diff --git a/3.0.2.tar.gz b/3.0.2.tar.gz deleted file mode 100644 index 5009442..0000000 --- a/3.0.2.tar.gz +++ /dev/null @@ -1,3 +0,0 @@ -version https://git-lfs.github.com/spec/v1 -oid sha256:c2c2dc505969bdb0797e1d3725f300ac796e4a0a140db137d3065b8f2ae1d27f -size 5496414 diff --git a/3.0.3.tar.gz b/3.0.3.tar.gz new file mode 100644 index 0000000..6c14598 --- /dev/null +++ b/3.0.3.tar.gz @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:5d96f6c411849420d4053643a2837c8411b331be60670e4590ad0e4c0a536e02 +size 5497106 diff --git a/scons-user.html b/scons-user.html new file mode 100644 index 0000000..a769f9e --- /dev/null +++ b/scons-user.html @@ -0,0 +1,21579 @@ +
version 3.0.3
Copyright © 2004 - 2019 The SCons Foundation
2004 - 2019
Table of Contents
Glob
Decider
FunctionDecider
Function$CPPPATH
Construction VariableDepends
FunctionParseDepends
+ FunctionIgnore
FunctionRequires
FunctionAlwaysBuild
FunctionConstruction Environment
: the Environment
FunctionConstruction Environment
Construction Environment
: the subst
MethodConstruction Environment
: the DefaultEnvironment
FunctionConstruction Environments
Construction Environments
: the Clone
MethodReplace
MethodSetDefault
MethodAppend
MethodAppendUnique
MethodPrepend
MethodPrependUnique
MethodSCONSFLAGS
Environment VariableGetOption
FunctionSetOption
FunctionAddOption
Functionvariable
=value
Build VariablesUnknownVariables
FunctionInstall
BuilderCopy
FactoryDelete
FactoryMove
FactoryTouch
FactoryMkdir
FactoryChmod
FactoryExecute
FunctionSConscript
CallVariantDir
FunctionVariantDir
With an SConscript
FileGlob
with VariantDir
Construction Environment
Generator
Emitter
Command
BuilderConfigure Contexts
typedef
EnsurePythonVersion
FunctionEnsureSConsVersion
FunctionSConscript
Files: the Exit
FunctionFindFile
FunctionFlatten
FunctionGetLaunchDir
Function--debug=explain
OptionDump
Method--tree
Option--debug=presub
Option--debug=findlibs
Option--debug=stacktrace
Option--taskmastertrace
Option--debug=prepare
OptionList of Examples
+ + Thank you for taking the time to read about SCons. + SCons is a next-generation + software construction tool, + or make tool--that is, a software utility + for building software (or other files) + and keeping built software up-to-date + whenever the underlying input files change. + +
+ + The most distinctive thing about SCons + is that its configuration files are + actually scripts, + written in the Python programming language. + This is in contrast to most alternative build tools, + which typically invent a new language to + configure the build. + SCons still has a learning curve, of course, + because you have to know what functions to call + to set up your build properly, + but the underlying syntax used should be familiar + to anyone who has ever looked at a Python script. + +
+ + Paradoxically, + using Python as the configuration file format + makes SCons + easier + for non-programmers to learn + than the cryptic languages of other build tools, + which are usually invented by programmers for other programmers. + This is in no small part due to the + consistency and readability that are hallmarks of Python. + It just so happens that making a real, live + scripting language the basis for the + configuration files + makes it a snap for more accomplished programmers + to do more complicated things with builds, + as necessary. + +
+ + There are a few overriding principles + we try to live up to in designing and implementing SCons: + +
+ + First and foremost, + by default, SCons guarantees a correct build + even if it means sacrificing performance a little. + We strive to guarantee the build is correct + regardless of how the software being built is structured, + how it may have been written, + or how unusual the tools are that build it. + +
+ + Given that the build is correct, + we try to make SCons build software + as quickly as possible. + In particular, wherever we may have needed to slow + down the default SCons behavior to guarantee a correct build, + we also try to make it easy to speed up SCons + through optimization options that let you trade off + guaranteed correctness in all end cases for + a speedier build in the usual cases. + +
+ + SCons tries to do as much for you out of the box as reasonable, + including detecting the right tools on your system + and using them correctly to build the software. + +
+ + In a nutshell, we try hard to make SCons just + "do the right thing" and build software correctly, + with a minimum of hassles. + +
+ + One word of warning as you read through this Guide: + Like too much Open Source software out there, + the SCons documentation isn't always + kept up-to-date with the available features. + In other words, + there's a lot that SCons can do that + isn't yet covered in this User's Guide. + (Come to think of it, + that also describes a lot of proprietary software, doesn't it?) + +
+ + Although this User's Guide isn't as complete as we'd like it to be, + our development process does emphasize + making sure that the SCons man page is kept up-to-date + with new features. + So if you're trying to figure out how to do something + that SCons supports + but can't find enough (or any) information here, + it would be worth your while to look + at the man page to see if the information is covered there. + And if you do, + maybe you'd even consider contributing + a section to the User's Guide + so the next person looking for + that information won't have to + go through the same thing...? + +
+ + SCons would not exist without a lot of help + from a lot of people, + many of whom may not even be aware + that they helped or served as inspiration. + So in no particular order, + and at the risk of leaving out someone: + +
+ + First and foremost, + SCons owes a tremendous debt to Bob Sidebotham, + the original author of the classic Perl-based Cons tool + which Bob first released to the world back around 1996. + Bob's work on Cons classic provided the underlying architecture + and model of specifying a build configuration + using a real scripting language. + My real-world experience working on Cons + informed many of the design decisions in SCons, + including the improved parallel build support, + making Builder objects easily definable by users, + and separating the build engine from the wrapping interface. + +
+ + Greg Wilson was instrumental in getting + SCons started as a real project + when he initiated the Software Carpentry design + competition in February 2000. + Without that nudge, + marrying the advantages of the Cons classic + architecture with the readability of Python + might have just stayed no more than a nice idea. + +
+ + The entire SCons team have been + absolutely wonderful to work with, + and SCons would be nowhere near as useful a + tool without the energy, enthusiasm + and time people have contributed over the past few years. + The "core team" + of Chad Austin, Anthony Roach, + Bill Deegan, Charles Crain, Steve Leblanc, Greg Noel, + Gary Oberbrunner, Greg Spencer and Christoph Wiedemann + have been great about reviewing my (and other) changes + and catching problems before they get in the code base. + Of particular technical note: + Anthony's outstanding and innovative work on the tasking engine + has given SCons a vastly superior parallel build model; + Charles has been the master of the crucial Node infrastructure; + Christoph's work on the Configure infrastructure + has added crucial Autoconf-like functionality; + and Greg has provided excellent support + for Microsoft Visual Studio. + +
+ + Special thanks to David Snopek for contributing + his underlying "Autoscons" code that formed + the basis of Christoph's work with the Configure functionality. + David was extremely generous in making + this code available to SCons, + given that he initially released it under the GPL + and SCons is released under a less-restrictive MIT-style license. + +
+ + Thanks to Peter Miller + for his splendid change management system, Aegis, + which has provided the SCons project + with a robust development methodology from day one, + and which showed me how you could + integrate incremental regression tests into + a practical development cycle + (years before eXtreme Programming arrived on the scene). + +
+ + And last, thanks to Guido van Rossum + for his elegant scripting language, + which is the basis not only for the SCons implementation, + but for the interface itself. + +
+ + The best way to contact people involved with SCons, + including the author, + is through the SCons mailing lists. + +
+
+ If you want to ask general questions about how to use SCons
+ send email to scons-users@scons.org
.
+
+
+
+ If you want to contact the SCons development community directly,
+ send email to scons-dev@scons.org
.
+
+
+
+ If you want to receive announcements about SCons,
+ join the low-volume announce@scons.tigris.org
mailing list.
+
+
+ + This chapter will take you through the basic steps + of installing SCons on your system, + and building SCons if you don't have a + pre-built package available + (or simply prefer the flexibility of building it yourself). + Before that, however, this chapter will also describe the basic steps + involved in installing Python on your system, + in case that is necessary. + Fortunately, both SCons and Python + are very easy to install on almost any system, + and Python already comes installed on many systems. + +
+ Because SCons is written in Python,
+ you need to have Python installed on your system
+ to use SCons.
+ Before you try to install Python,
+ you should check to see if Python is already
+ available on your system by typing
+ python -V
+ (capital 'V')
+ or
+ python --version
+ at your system's command-line prompt.
+ For Linux/Unix/MacOS/BSD type systems this looks like:
+
+$ python -V
+Python 3.7.1
+
+ In a cmd shell or PowerShell on a Windows system + (note PoweShell needs it spelled "python.exe" rather than "python"): +
+C:\>python -V
+Python 3.7.1
+
+ If Python is not installed on your system, + you will see an error message + stating something like "command not found" + (on UNIX or Linux) + or "'python' is not recognized + as an internal or external command, operable progam or batch file" + (on Windows). + In that case, you need to install Python + before you can install SCons. +
+ The standard location for information + about downloading and installing Python is + http://www.python.org/download/. + See that page and associated links to get started. +
+ For Linux systems, Python is + almost certainly available as a supported package, possibly + installed by default; this is often preferred to installing + by other means, and is easier than installing from source code. + Many such systems have separate packages for + Python 2 and Python 3. Building from source may still be a + useful option if you need a version that is not offered by + the distribution you are using. +
+ SCons will work with Python 2.7.x or with Python 3.5 or later. + If you need to install Python and have a choice, + we recommend using the most recent Python version available. + Newer Pythons have significant improvements + that help speed up the performance of SCons. +
+ The canonical way to install SCons is from the Python Package + Index (PyPi): +
+% python -m pip install scons
+
+ If you prefer not to install to the Python system location, + or do not have privileges to do so, you can add a flag to + install to a location specific to your own account: +
+% python -m pip install --user scons
+
+ SCons comes pre-packaged for installation on many Linux systems
+ Check your package installation system
+ to see if there is an SCons package available.
+ Many people prefer to install distribution-native packages if available,
+ as they provide a central point for management and updating.
+ Some distributions have two SCons packages available, one which
+ uses Python 2 and one which uses Python 3. If you need a specific
+ version of SCons that is different from the package available,
+ pip
has a version option or you can follow
+ the instructions in the next section.
+
+ If a pre-built SCons package is not available for your system,
+ and installing using pip
is not suitable,
+ then you can still easily build and install SCons using the native
+ Python distutils
package.
+
+ The first step is to download either the
+ scons-3.0.3.tar.gz
+ or scons-3.0.3.zip
,
+ which are available from the SCons download page at
+ http://www.scons.org/download.html.
+
+ Unpack the archive you downloaded,
+ using a utility like tar
+ on Linux or UNIX,
+ or WinZip on Windows.
+ This will create a directory called
+ scons-3.0.3
,
+ usually in your local directory.
+ Then change your working directory to that directory
+ and install SCons by executing the following commands:
+
+#cd scons-3.0.3
+#python setup.py install
+
+
+ This will build SCons,
+ install the scons
script
+ in the python which is used to run the setup.py's scripts directory
+ (/usr/local/bin
or
+ C:\Python27\Scripts
),
+ and will install the SCons build engine
+ in the corresponding library directory for the python used
+ (/usr/local/lib/scons
or
+ C:\Python27\scons
).
+ Because these are system directories,
+ you may need root (on Linux or UNIX) or Administrator (on Windows)
+ privileges to install SCons like this.
+
+
+
+ The SCons setup.py
script
+ has some extensions that support
+ easy installation of multiple versions of SCons
+ in side-by-side locations.
+ This makes it easier to download and
+ experiment with different versions of SCons
+ before moving your official build process to a new version,
+ for example.
+
+
+
+ To install SCons in a version-specific location,
+ add the --version-lib
option
+ when you call setup.py
:
+
+
+# python setup.py install --version-lib
+
+
+ This will install the SCons build engine
+ in the
+ /usr/lib/scons-3.0.3
+ or
+ C:\Python27\scons-3.0.3
+ directory, for example.
+
+
+
+ If you use the --version-lib
option
+ the first time you install SCons,
+ you do not need to specify it each time you install
+ a new version.
+ The SCons setup.py
script
+ will detect the version-specific directory name(s)
+ and assume you want to install all versions
+ in version-specific directories.
+ You can override that assumption in the future
+ by explicitly specifying the --standalone-lib
option.
+
+
+
+ You can install SCons in locations other than
+ the default by specifying the --prefix=
option:
+
+
+# python setup.py install --prefix=/opt/scons
+
+
+ This would
+ install the scons script in
+ /opt/scons/bin
+ and the build engine in
+ /opt/scons/lib/scons
,
+
+
+
+ Note that you can specify both the --prefix=
+ and the --version-lib
options
+ at the same type,
+ in which case setup.py
+ will install the build engine
+ in a version-specific directory
+ relative to the specified prefix.
+ Adding --version-lib
to the
+ above example would install the build engine in
+ /opt/scons/lib/scons-3.0.3
.
+
+
+
+ If you don't have the right privileges to install SCons
+ in a system location,
+ simply use the --prefix=
option
+ to install it in a location of your choosing.
+ For example,
+ to install SCons in appropriate locations
+ relative to the user's $HOME
directory,
+ the scons
script in
+ $HOME/bin
+ and the build engine in
+ $HOME/lib/scons
,
+ simply type:
+
+
+$ python setup.py install --prefix=$HOME
+
+
+ You may, of course, specify any other location you prefer,
+ and may use the --version-lib
option
+ if you would like to install version-specific directories
+ relative to the specified prefix.
+
+
+
+ This can also be used to experiment with a newer
+ version of SCons than the one installed
+ in your system locations.
+ Of course, the location in which you install the
+ newer version of the scons
script
+ ($HOME/bin
in the above example)
+ must be configured in your PATH
variable
+ before the directory containing
+ the system-installed version
+ of the scons
script.
+
+
+ + In this chapter, + you will see several examples of + very simple build configurations using SCons, + which will demonstrate how easy + it is to use SCons to + build programs from several different programming languages + on different types of systems. + +
+ + Here's the famous "Hello, World!" program in C: + +
+int +main() +{ + printf("Hello, world!\n"); +} +
+
+ And here's how to build it using SCons.
+ Enter the following into a file named SConstruct
:
+
+
+Program('hello.c') +
+
+ This minimal configuration file gives
+ SCons two pieces of information:
+ what you want to build
+ (an executable program),
+ and the input file from
+ which you want it built
+ (the hello.c
file).
+ Program
is a builder_method,
+ a Python call that tells SCons that you want to build an
+ executable program.
+
+
+
+ That's it. Now run the scons
command to build the program.
+ On a POSIX-compliant system like Linux or UNIX,
+ you'll see something like:
+
+
% scons
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+scons: Building targets ...
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+scons: done building targets.
+
+ + On a Windows system with the Microsoft Visual C++ compiler, + you'll see something like: + +
C:\>scons
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+scons: Building targets ...
+cl /Fohello.obj /c hello.c /nologo
+link /nologo /OUT:hello.exe hello.obj
+embedManifestExeCheck(target, source, env)
+scons: done building targets.
+
+ + First, notice that you only need + to specify the name of the source file, + and that SCons correctly deduces the names of + the object and executable files to be built + from the base of the source file name. + +
+
+ Second, notice that the same input SConstruct
file,
+ without any changes,
+ generates the correct output file names on both systems:
+ hello.o
and hello
+ on POSIX systems,
+ hello.obj
and hello.exe
+ on Windows systems.
+ This is a simple example of how SCons
+ makes it extremely easy to
+ write portable software builds.
+
+
+ + (Note that we won't provide duplicate side-by-side + POSIX and Windows output for all of the examples in this guide; + just keep in mind that, unless otherwise specified, + any of the examples should work equally well on both types of systems.) + +
+
+ The Program
builder method is only one of
+ many builder methods that SCons provides
+ to build different types of files.
+ Another is the Object
builder method,
+ which tells SCons to build an object file
+ from the specified source file:
+
+
+Object('hello.c') +
+
+ Now when you run the scons
command to build the program,
+ it will build just the hello.o
object file on a POSIX system:
+
+
% scons
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+scons: Building targets ...
+cc -o hello.o -c hello.c
+scons: done building targets.
+
+
+ And just the hello.obj
object file
+ on a Windows system (with the Microsoft Visual C++ compiler):
+
+
C:\>scons
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+scons: Building targets ...
+cl /Fohello.obj /c hello.c /nologo
+scons: done building targets.
+
+
+ SCons also makes building with Java extremely easy.
+ Unlike the Program
and Object
builder methods,
+ however, the Java
builder method
+ requires that you specify
+ the name of a destination directory in which
+ you want the class files placed,
+ followed by the source directory
+ in which the .java
files live:
+
+
+Java('classes', 'src') +
+
+ If the src
directory
+ contains a single hello.java
file,
+ then the output from running the scons
command
+ would look something like this
+ (on a POSIX system):
+
+
% scons
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+scons: Building targets ...
+javac -d classes -sourcepath src src/hello.java
+scons: done building targets.
+
+
+ We'll cover Java builds in more detail,
+ including building Java archive (.jar
)
+ and other types of file,
+ in Chapter 26, Java Builds.
+
+
+
+ When using SCons, it is unnecessary to add special
+ commands or target names to clean up after a build.
+ Instead, you simply use the
+ -c
or --clean
+ option when you invoke SCons,
+ and SCons removes the appropriate built files.
+ So if we build our example above
+ and then invoke scons -c
+ afterwards, the output on POSIX looks like:
+
+
%scons
+scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Building targets ... +cc -o hello.o -c hello.c +cc -o hello hello.o +scons: done building targets. +%scons -c
+scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Cleaning targets ... +Removed hello.o +Removed hello +scons: done cleaning targets. +
+ + And the output on Windows looks like: + +
C:\>scons
+scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Building targets ... +cl /Fohello.obj /c hello.c /nologo +link /nologo /OUT:hello.exe hello.obj +embedManifestExeCheck(target, source, env) +scons: done building targets. +C:\>scons -c
+scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Cleaning targets ... +Removed hello.obj +Removed hello.exe +scons: done cleaning targets. +
+
+ Notice that SCons changes its output to tell you that it
+ is Cleaning targets ...
and
+ done cleaning targets.
+
+
+
+ If you're used to build systems like Make
+ you've already figured out that the SConstruct
file
+ is the SCons equivalent of a Makefile
.
+ That is, the SConstruct
file is the input file
+ that SCons reads to control the build.
+
+
+
+ There is, however, an important difference between
+ an SConstruct
file and a Makefile
:
+ the SConstruct
file is actually a Python script.
+ If you're not already familiar with Python, don't worry.
+ This User's Guide will introduce you step-by-step
+ to the relatively small amount of Python you'll
+ need to know to be able to use SCons effectively.
+ And Python is very easy to learn.
+
+
+
+ One aspect of using Python as the
+ scripting language is that you can put comments
+ in your SConstruct
file using Python's commenting convention;
+ that is, everything between a '#' and the end of the line
+ will be ignored:
+
+
+# Arrange to build the "hello" program. +Program('hello.c') # "hello.c" is the source file. +
+ + You'll see throughout the remainder of this Guide + that being able to use the power of a + real scripting language + can greatly simplify the solutions + to complex requirements of real-world builds. + +
+
+ One important way in which the SConstruct
+ file is not exactly like a normal Python script,
+ and is more like a Makefile
,
+ is that the order in which
+ the SCons functions are called in
+ the SConstruct
file
+ does not
+ affect the order in which SCons
+ actually builds the programs and object files
+ you want it to build.[1]
+ In other words, when you call the Program
builder
+ (or any other builder method),
+ you're not telling SCons to build
+ the program at the instant the builder method is called.
+ Instead, you're telling SCons to build the program
+ that you want, for example,
+ a program built from a file named hello.c
,
+ and it's up to SCons to build that program
+ (and any other files) whenever it's necessary.
+ (We'll learn more about how
+ SCons decides when building or rebuilding a file
+ is necessary in Chapter 6, Dependencies, below.)
+
+
+
+ SCons reflects this distinction between
+ calling a builder method like Program
+ and actually building the program
+ by printing the status messages that indicate
+ when it's "just reading" the SConstruct
file,
+ and when it's actually building the target files.
+ This is to make it clear when SCons is
+ executing the Python statements that make up the SConstruct
file,
+ and when SCons is actually executing the
+ commands or other actions to
+ build the necessary files.
+
+
+
+ Let's clarify this with an example.
+ Python has a print
statement that
+ prints a string of characters to the screen.
+ If we put print
statements around
+ our calls to the Program
builder method:
+
+
+print("Calling Program('hello.c')") +Program('hello.c') +print("Calling Program('goodbye.c')") +Program('goodbye.c') +print("Finished calling Program()") +
+
+ Then when we execute SCons,
+ we see the output from the print
+ statements in between the messages about
+ reading the SConscript
files,
+ indicating that that is when the
+ Python statements are being executed:
+
+
% scons
+scons: Reading SConscript files ...
+Calling Program('hello.c')
+Calling Program('goodbye.c')
+Finished calling Program()
+scons: done reading SConscript files.
+scons: Building targets ...
+cc -o goodbye.o -c goodbye.c
+cc -o goodbye goodbye.o
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+scons: done building targets.
+
+
+ Notice also that SCons built the goodbye
program first,
+ even though the "reading SConscript
" output
+ shows that we called Program('hello.c')
+ first in the SConstruct
file.
+
+
+ + You've already seen how SCons prints + some messages about what it's doing, + surrounding the actual commands used to build the software: + +
C:\>scons
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+scons: Building targets ...
+cl /Fohello.obj /c hello.c /nologo
+link /nologo /OUT:hello.exe hello.obj
+embedManifestExeCheck(target, source, env)
+scons: done building targets.
+
+
+ These messages emphasize the
+ order in which SCons does its work:
+ all of the configuration files
+ (generically referred to as SConscript
files)
+ are read and executed first,
+ and only then are the target files built.
+ Among other benefits, these messages help to distinguish between
+ errors that occur while the configuration files are read,
+ and errors that occur while targets are being built.
+
+
+
+ One drawback, of course, is that these messages clutter the output.
+ Fortunately, they're easily disabled by using
+ the -Q
option when invoking SCons:
+
+
C:\>scons -Q
+cl /Fohello.obj /c hello.c /nologo
+link /nologo /OUT:hello.exe hello.obj
+embedManifestExeCheck(target, source, env)
+
+
+ Because we want this User's Guide to focus
+ on what SCons is actually doing,
+ we're going to use the -Q
option
+ to remove these messages from the
+ output of all the remaining examples in this Guide.
+
+
[1] In programming parlance,
+ the SConstruct
file is
+ declarative,
+ meaning you tell SCons what you want done
+ and let it figure out the order in which to do it,
+ rather than strictly imperative,
+ where you specify explicitly the order in
+ which to do things.
+
+ + In this chapter, + you will see several examples of + very simple build configurations using SCons, + which will demonstrate how easy + it is to use SCons to + build programs from several different programming languages + on different types of systems. + +
+
+ You've seen that when you call the Program
builder method,
+ it builds the resulting program with the same
+ base name as the source file.
+ That is, the following call to build an
+ executable program from the hello.c
source file
+ will build an executable program named hello
on POSIX systems,
+ and an executable program named hello.exe
on Windows systems:
+
+
+Program('hello.c') +
+ + If you want to build a program with + a different name than the base of the source file name, + you simply put the target file name + to the left of the source file name: + +
+Program('new_hello', 'hello.c') +
+
+ (SCons requires the target file name first,
+ followed by the source file name,
+ so that the order mimics that of an
+ assignment statement in most programming languages,
+ including Python:
+ "program = source files"
.)
+
+
+
+ Now SCons will build an executable program
+ named new_hello
when run on a POSIX system:
+
+
% scons -Q
+cc -o hello.o -c hello.c
+cc -o new_hello hello.o
+
+
+ And SCons will build an executable program
+ named new_hello.exe
when run on a Windows system:
+
+
C:\>scons -Q
+cl /Fohello.obj /c hello.c /nologo
+link /nologo /OUT:new_hello.exe hello.obj
+embedManifestExeCheck(target, source, env)
+
+ + You've just seen how to configure SCons + to compile a program from a single source file. + It's more common, of course, + that you'll need to build a program from + many input source files, not just one. + To do this, you need to put the + source files in a Python list + (enclosed in square brackets), + like so: + +
+Program(['prog.c', 'file1.c', 'file2.c']) +
+ + A build of the above example would look like: + +
% scons -Q
+cc -o file1.o -c file1.c
+cc -o file2.o -c file2.c
+cc -o prog.o -c prog.c
+cc -o prog prog.o file1.o file2.o
+
+
+ Notice that SCons
+ deduces the output program name
+ from the first source file specified
+ in the list--that is,
+ because the first source file was prog.c
,
+ SCons will name the resulting program prog
+ (or prog.exe
on a Windows system).
+ If you want to specify a different program name,
+ then (as we've seen in the previous section)
+ you slide the list of source files
+ over to the right
+ to make room for the output program file name.
+ (SCons puts the output file name to the left
+ of the source file names
+ so that the order mimics that of an
+ assignment statement: "program = source files".)
+ This makes our example:
+
+
+Program('program', ['prog.c', 'file1.c', 'file2.c']) +
+ + On Linux, a build of this example would look like: + +
% scons -Q
+cc -o file1.o -c file1.c
+cc -o file2.o -c file2.c
+cc -o prog.o -c prog.c
+cc -o program prog.o file1.o file2.o
+
+ + Or on Windows: + +
C:\>scons -Q
+cl /Fofile1.obj /c file1.c /nologo
+cl /Fofile2.obj /c file2.c /nologo
+cl /Foprog.obj /c prog.c /nologo
+link /nologo /OUT:program.exe prog.obj file1.obj file2.obj
+embedManifestExeCheck(target, source, env)
+
+
+ You can also use the Glob
function to find all files matching a
+ certain template, using the standard shell pattern matching
+ characters *
, ?
+ and [abc]
to match any of
+ a
, b
or c
.
+ [!abc]
is also supported,
+ to match any character except
+ a
, b
or c
.
+ This makes many multi-source-file builds quite easy:
+
+
+Program('program', Glob('*.c')) +
+
+ The SCons man page has more details on using Glob
+ with variant directories
+ (see Chapter 16, Variant Builds, below)
+ and repositories
+ (see Chapter 22, Building From Code Repositories, below),
+ excluding some files
+ and returning strings rather than Nodes.
+
+
+ + We've now shown you two ways to specify + the source for a program, + one with a list of files: + +
+Program('hello', ['file1.c', 'file2.c']) +
+ + And one with a single file: + +
+Program('hello', 'hello.c') +
+ + You could actually put a single file name in a list, too, + which you might prefer just for the sake of consistency: + +
+Program('hello', ['hello.c']) +
+ + SCons functions will accept a single file name in either form. + In fact, internally, SCons treats all input as lists of files, + but allows you to omit the square brackets + to cut down a little on the typing + when there's only a single file name. + +
+ + Although SCons functions + are forgiving about whether or not you + use a string vs. a list for a single file name, + Python itself is more strict about + treating lists and strings differently. + So where SCons allows either + a string or list: + +
+# The following two calls both work correctly: +Program('program1', 'program1.c') +Program('program2', ['program2.c']) +
+ + Trying to do "Python things" that mix strings and + lists will cause errors or lead to incorrect results: + +
+common_sources = ['file1.c', 'file2.c'] + +# THE FOLLOWING IS INCORRECT AND GENERATES A PYTHON ERROR +# BECAUSE IT TRIES TO ADD A STRING TO A LIST: +Program('program1', common_sources + 'program1.c') + +# The following works correctly, because it's adding two +# lists together to make another list. +Program('program2', common_sources + ['program2.c']) +
+
+ One drawback to the use of a Python list
+ for source files is that
+ each file name must be enclosed in quotes
+ (either single quotes or double quotes).
+ This can get cumbersome and difficult to read
+ when the list of file names is long.
+ Fortunately, SCons and Python provide a number of ways
+ to make sure that
+ the SConstruct
file stays easy to read.
+
+
+
+ To make long lists of file names
+ easier to deal with, SCons provides a
+ Split
function
+ that takes a quoted list of file names,
+ with the names separated by spaces or other white-space characters,
+ and turns it into a list of separate file names.
+ Using the Split
function turns the
+ previous example into:
+
+
+Program('program', Split('main.c file1.c file2.c')) +
+
+ (If you're already familiar with Python,
+ you'll have realized that this is similar to the
+ split()
method
+ in the Python standard string
module.
+ Unlike the split()
member function of strings,
+ however, the Split
function
+ does not require a string as input
+ and will wrap up a single non-string object in a list,
+ or return its argument untouched if it's already a list.
+ This comes in handy as a way to make sure
+ arbitrary values can be passed to SCons functions
+ without having to check the type of the variable by hand.)
+
+
+
+ Putting the call to the Split
function
+ inside the Program
call
+ can also be a little unwieldy.
+ A more readable alternative is to
+ assign the output from the Split
call
+ to a variable name,
+ and then use the variable when calling the
+ Program
function:
+
+
+src_files = Split('main.c file1.c file2.c') +Program('program', src_files) +
+
+ Lastly, the Split
function
+ doesn't care how much white space separates
+ the file names in the quoted string.
+ This allows you to create lists of file
+ names that span multiple lines,
+ which often makes for easier editing:
+
+
+src_files = Split("""main.c + file1.c + file2.c""") +Program('program', src_files) +
+ + (Note in this example that we used + the Python "triple-quote" syntax, + which allows a string to contain + multiple lines. + The three quotes can be either + single or double quotes.) + +
+ + SCons also allows you to identify + the output file and input source files + using Python keyword arguments. + The output file is known as the + target, + and the source file(s) are known (logically enough) as the + source. + The Python syntax for this is: + +
+src_files = Split('main.c file1.c file2.c') +Program(target = 'program', source = src_files) +
+ + Because the keywords explicitly identify + what each argument is, + you can actually reverse the order if you prefer: + +
+src_files = Split('main.c file1.c file2.c') +Program(source = src_files, target = 'program') +
+ + Whether or not you choose to use keyword arguments + to identify the target and source files, + and the order in which you specify them + when using keywords, + are purely personal choices; + SCons functions the same regardless. + +
+
+ In order to compile multiple programs
+ within the same SConstruct
file,
+ simply call the Program
method
+ multiple times,
+ once for each program you need to build:
+
+
+Program('foo.c') +Program('bar', ['bar1.c', 'bar2.c']) +
+ + SCons would then build the programs as follows: + +
% scons -Q
+cc -o bar1.o -c bar1.c
+cc -o bar2.o -c bar2.c
+cc -o bar bar1.o bar2.o
+cc -o foo.o -c foo.c
+cc -o foo foo.o
+
+
+ Notice that SCons does not necessarily build the
+ programs in the same order in which you specify
+ them in the SConstruct
file.
+ SCons does, however, recognize that
+ the individual object files must be built
+ before the resulting program can be built.
+ We'll discuss this in greater detail in
+ the "Dependencies" section, below.
+
+
+ + It's common to re-use code by sharing source files + between multiple programs. + One way to do this is to create a library + from the common source files, + which can then be linked into resulting programs. + (Creating libraries is discussed in + Chapter 4, Building and Linking with Libraries, below.) + +
+ + A more straightforward, but perhaps less convenient, + way to share source files between multiple programs + is simply to include the common files + in the lists of source files for each program: + +
+Program(Split('foo.c common1.c common2.c')) +Program('bar', Split('bar1.c bar2.c common1.c common2.c')) +
+
+ SCons recognizes that the object files for
+ the common1.c
and common2.c
source files
+ each need to be built only once,
+ even though the resulting object files are
+ each linked in to both of the resulting executable programs:
+
+
% scons -Q
+cc -o bar1.o -c bar1.c
+cc -o bar2.o -c bar2.c
+cc -o common1.o -c common1.c
+cc -o common2.o -c common2.c
+cc -o bar bar1.o bar2.o common1.o common2.o
+cc -o foo.o -c foo.c
+cc -o foo foo.o common1.o common2.o
+
+
+ If two or more programs
+ share a lot of common source files,
+ repeating the common files in the list for each program
+ can be a maintenance problem when you need to change the
+ list of common files.
+ You can simplify this by creating a separate Python list
+ to hold the common file names,
+ and concatenating it with other lists
+ using the Python +
operator:
+
+
+common = ['common1.c', 'common2.c'] +foo_files = ['foo.c'] + common +bar_files = ['bar1.c', 'bar2.c'] + common +Program('foo', foo_files) +Program('bar', bar_files) +
+ + This is functionally equivalent to the previous example. + +
+ + It is possible to override or add construction variables + when calling a builder method by passing additional keyword arguments. + These overridden or added variables will only be in effect when + building the target, so they will not affect other parts of the build. + For example, if you want to add additional libraries for just one program: + +
+env.Program('hello', 'hello.c', LIBS=['gl', 'glut']) +
+ + or generate a shared library with a non-standard suffix: + +
+env.SharedLibrary('word', 'word.cpp', + SHLIBSUFFIX='.ocx', + LIBSUFFIXES=['.ocx']) +
+
+ It is also possible to use the parse_flags
keyword argument in an
+ override:
+
+
+
+ This example adds 'include' to $CPPPATH
,
+ 'EBUG' to $CPPDEFINES
, and 'm' to $LIBS
.
+
+
+env = Program('hello', 'hello.c', parse_flags = '-Iinclude -DEBUG -lm') +
+ + Within the call to the builder action the environment is not cloned, + instead an OverrideEnvironment() is created which is more + light weight than a whole Environment() + +
+ + It's often useful to organize large software projects + by collecting parts of the software into one or more libraries. + SCons makes it easy to create libraries + and to use them in the programs. + +
+
+ You build your own libraries by specifying Library
+ instead of Program
:
+
+
+Library('foo', ['f1.c', 'f2.c', 'f3.c']) +
+ + SCons uses the appropriate library prefix and suffix for your system. + So on POSIX or Linux systems, + the above example would build as follows + (although ranlib may not be called on all systems): + +
% scons -Q
+cc -o f1.o -c f1.c
+cc -o f2.o -c f2.c
+cc -o f3.o -c f3.c
+ar rc libfoo.a f1.o f2.o f3.o
+ranlib libfoo.a
+
+ + On a Windows system, + a build of the above example would look like: + +
C:\>scons -Q
+cl /Fof1.obj /c f1.c /nologo
+cl /Fof2.obj /c f2.c /nologo
+cl /Fof3.obj /c f3.c /nologo
+lib /nologo /OUT:foo.lib f1.obj f2.obj f3.obj
+
+ + The rules for the target name of the library + are similar to those for programs: + if you don't explicitly specify a target library name, + SCons will deduce one from the + name of the first source file specified, + and SCons will add an appropriate + file prefix and suffix if you leave them off. + +
+
+ The previous example shows building a library from a
+ list of source files.
+ You can, however, also give the Library
call
+ object files,
+ and it will correctly realize they are object files.
+ In fact, you can arbitrarily mix source code files
+ and object files in the source list:
+
+
+Library('foo', ['f1.c', 'f2.o', 'f3.c', 'f4.o']) +
+ + And SCons realizes that only the source code files + must be compiled into object files + before creating the final library: + +
% scons -Q
+cc -o f1.o -c f1.c
+cc -o f3.o -c f3.c
+ar rc libfoo.a f1.o f2.o f3.o f4.o
+ranlib libfoo.a
+
+ + Of course, in this example, the object files + must already exist for the build to succeed. + See Chapter 5, Node Objects, below, + for information about how you can + build object files explicitly + and include the built files in a library. + +
+
+ The Library
function builds a traditional static library.
+ If you want to be explicit about the type of library being built,
+ you can use the synonym StaticLibrary
function
+ instead of Library
:
+
+
+StaticLibrary('foo', ['f1.c', 'f2.c', 'f3.c']) +
+
+ There is no functional difference between the
+ StaticLibrary
and Library
functions.
+
+
+
+ If you want to build a shared library (on POSIX systems)
+ or a DLL file (on Windows systems),
+ you use the SharedLibrary
function:
+
+
+SharedLibrary('foo', ['f1.c', 'f2.c', 'f3.c']) +
+ + The output on POSIX: + +
% scons -Q
+cc -o f1.os -c f1.c
+cc -o f2.os -c f2.c
+cc -o f3.os -c f3.c
+cc -o libfoo.so -shared f1.os f2.os f3.os
+
+ + And the output on Windows: + +
C:\>scons -Q
+cl /Fof1.obj /c f1.c /nologo
+cl /Fof2.obj /c f2.c /nologo
+cl /Fof3.obj /c f3.c /nologo
+link /nologo /dll /out:foo.dll /implib:foo.lib f1.obj f2.obj f3.obj
+RegServerFunc(target, source, env)
+embedManifestDllCheck(target, source, env)
+
+
+ Notice again that SCons takes care of
+ building the output file correctly,
+ adding the -shared
option
+ for a POSIX compilation,
+ and the /dll
option on Windows.
+
+
+
+ Usually, you build a library
+ because you want to link it with one or more programs.
+ You link libraries with a program by specifying
+ the libraries in the $LIBS
construction variable,
+ and by specifying the directory in which
+ the library will be found in the
+ $LIBPATH
construction variable:
+
+
+
+
+Library('foo', ['f1.c', 'f2.c', 'f3.c']) +Program('prog.c', LIBS=['foo', 'bar'], LIBPATH='.') +
+
+ Notice, of course, that you don't need to specify a library
+ prefix (like lib
)
+ or suffix (like .a
or .lib
).
+ SCons uses the correct prefix or suffix for the current system.
+
+
+ + On a POSIX or Linux system, + a build of the above example would look like: + +
% scons -Q
+cc -o f1.o -c f1.c
+cc -o f2.o -c f2.c
+cc -o f3.o -c f3.c
+ar rc libfoo.a f1.o f2.o f3.o
+ranlib libfoo.a
+cc -o prog.o -c prog.c
+cc -o prog prog.o -L. -lfoo -lbar
+
+ + On a Windows system, + a build of the above example would look like: + +
C:\>scons -Q
+cl /Fof1.obj /c f1.c /nologo
+cl /Fof2.obj /c f2.c /nologo
+cl /Fof3.obj /c f3.c /nologo
+lib /nologo /OUT:foo.lib f1.obj f2.obj f3.obj
+cl /Foprog.obj /c prog.c /nologo
+link /nologo /OUT:prog.exe /LIBPATH:. foo.lib bar.lib prog.obj
+embedManifestExeCheck(target, source, env)
+
+ + As usual, notice that SCons has taken care + of constructing the correct command lines + to link with the specified library on each system. + +
+ + Note also that, + if you only have a single library to link with, + you can specify the library name in single string, + instead of a Python list, + so that: + +
+Program('prog.c', LIBS='foo', LIBPATH='.') +
+ + is equivalent to: + +
+Program('prog.c', LIBS=['foo'], LIBPATH='.') +
+ + This is similar to the way that SCons + handles either a string or a list to + specify a single source file. + +
+
+ By default, the linker will only look in
+ certain system-defined directories for libraries.
+ SCons knows how to look for libraries
+ in directories that you specify with the
+ $LIBPATH
construction variable.
+ $LIBPATH
consists of a list of
+ directory names, like so:
+
+
+Program('prog.c', LIBS = 'm', + LIBPATH = ['/usr/lib', '/usr/local/lib']) +
+ + Using a Python list is preferred because it's portable + across systems. Alternatively, you could put all of + the directory names in a single string, separated by the + system-specific path separator character: + a colon on POSIX systems: + +
+LIBPATH = '/usr/lib:/usr/local/lib' +
+ + or a semi-colon on Windows systems: + +
+LIBPATH = 'C:\\lib;D:\\lib' +
+ + (Note that Python requires that the backslash + separators in a Windows path name + be escaped within strings.) + +
+ + When the linker is executed, + SCons will create appropriate flags + so that the linker will look for + libraries in the same directories as SCons. + So on a POSIX or Linux system, + a build of the above example would look like: + +
% scons -Q
+cc -o prog.o -c prog.c
+cc -o prog prog.o -L/usr/lib -L/usr/local/lib -lm
+
+ + On a Windows system, + a build of the above example would look like: + +
C:\>scons -Q
+cl /Foprog.obj /c prog.c /nologo
+link /nologo /OUT:prog.exe /LIBPATH:\usr\lib /LIBPATH:\usr\local\lib m.lib prog.obj
+embedManifestExeCheck(target, source, env)
+
+ + Note again that SCons has taken care of + the system-specific details of creating + the right command-line options. + +
+
+ Internally, SCons represents all of the files
+ and directories it knows about as Nodes
.
+ These internal objects
+ (not object files)
+ can be used in a variety of ways
+ to make your SConscript
+ files portable and easy to read.
+
+
+
+ All builder methods return a list of
+ Node
objects that identify the
+ target file or files that will be built.
+ These returned Nodes
can be passed
+ as arguments to other builder methods.
+
+
+
+ For example, suppose that we want to build
+ the two object files that make up a program with different options.
+ This would mean calling the Object
+ builder once for each object file,
+ specifying the desired options:
+
+
+Object('hello.c', CCFLAGS='-DHELLO') +Object('goodbye.c', CCFLAGS='-DGOODBYE') +
+
+ One way to combine these object files
+ into the resulting program
+ would be to call the Program
+ builder with the names of the object files
+ listed as sources:
+
+
+Object('hello.c', CCFLAGS='-DHELLO') +Object('goodbye.c', CCFLAGS='-DGOODBYE') +Program(['hello.o', 'goodbye.o']) +
+
+ The problem with specifying the names as strings
+ is that our SConstruct
file is no longer portable
+ across operating systems.
+ It won't, for example, work on Windows
+ because the object files there would be
+ named hello.obj
and goodbye.obj
,
+ not hello.o
and goodbye.o
.
+
+
+
+ A better solution is to assign the lists of targets
+ returned by the calls to the Object
builder to variables,
+ which we can then concatenate in our
+ call to the Program
builder:
+
+
+hello_list = Object('hello.c', CCFLAGS='-DHELLO') +goodbye_list = Object('goodbye.c', CCFLAGS='-DGOODBYE') +Program(hello_list + goodbye_list) +
+
+ This makes our SConstruct
file portable again,
+ the build output on Linux looking like:
+
+
% scons -Q
+cc -o goodbye.o -c -DGOODBYE goodbye.c
+cc -o hello.o -c -DHELLO hello.c
+cc -o hello hello.o goodbye.o
+
+ + And on Windows: + +
C:\>scons -Q
+cl /Fogoodbye.obj /c goodbye.c -DGOODBYE
+cl /Fohello.obj /c hello.c -DHELLO
+link /nologo /OUT:hello.exe hello.obj goodbye.obj
+embedManifestExeCheck(target, source, env)
+
+ + We'll see examples of using the list of nodes + returned by builder methods throughout + the rest of this guide. + +
+
+ It's worth mentioning here that
+ SCons maintains a clear distinction
+ between Nodes that represent files
+ and Nodes that represent directories.
+ SCons supports File
and Dir
+ functions that, respectively,
+ return a file or directory Node:
+
+
+hello_c = File('hello.c') +Program(hello_c) + +classes = Dir('classes') +Java(classes, 'src') +
+
+ Normally, you don't need to call
+ File
or Dir
directly,
+ because calling a builder method automatically
+ treats strings as the names of files or directories,
+ and translates them into
+ the Node objects for you.
+ The File
and Dir
functions can come in handy
+ in situations where you need to explicitly
+ instruct SCons about the type of Node being
+ passed to a builder or other function,
+ or unambiguously refer to a specific
+ file in a directory tree.
+
+
+
+
+ There are also times when you may need to
+ refer to an entry in a file system
+ without knowing in advance
+ whether it's a file or a directory.
+ For those situations,
+ SCons also supports an Entry
function,
+ which returns a Node
+ that can represent either a file or a directory.
+
+
+xyzzy = Entry('xyzzy') +
+
+ The returned xyzzy
Node
+ will be turned into a file or directory Node
+ the first time it is used by a builder method
+ or other function that
+ requires one vs. the other.
+
+
+
+ One of the most common things you can do
+ with a Node is use it to print the
+ file name that the node represents.
+ Keep in mind, though, that because the object
+ returned by a builder call
+ is a list of Nodes,
+ you must use Python subscripts
+ to fetch individual Nodes from the list.
+ For example, the following SConstruct
file:
+
+
+object_list = Object('hello.c') +program_list = Program(object_list) +print("The object file is: %s"%object_list[0]) +print("The program file is: %s"%program_list[0]) +
+ + Would print the following file names on a POSIX system: + +
% scons -Q
+The object file is: hello.o
+The program file is: hello
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+
+ + And the following file names on a Windows system: + +
C:\>scons -Q
+The object file is: hello.obj
+The program file is: hello.exe
+cl /Fohello.obj /c hello.c /nologo
+link /nologo /OUT:hello.exe hello.obj
+embedManifestExeCheck(target, source, env)
+
+
+ Note that in the above example,
+ the object_list[0]
+ extracts an actual Node object
+ from the list,
+ and the Python print
statement
+ converts the object to a string for printing.
+
+
+
+ Printing a Node
's name
+ as described in the previous section
+ works because the string representation of a Node
object
+ is the name of the file.
+ If you want to do something other than
+ print the name of the file,
+ you can fetch it by using the builtin Python
+ str
function.
+ For example, if you want to use the Python
+ os.path.exists
+ to figure out whether a file
+ exists while the SConstruct
file
+ is being read and executed,
+ you can fetch the string as follows:
+
+
+import os.path +program_list = Program('hello.c') +program_name = str(program_list[0]) +if not os.path.exists(program_name): + print("%s does not exist!"%program_name) +
+ + Which executes as follows on a POSIX system: + +
% scons -Q
+hello does not exist!
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+
+
+ env.GetBuildPath(file_or_list)
+ returns the path of a Node
or a string representing a
+ path. It can also take a list of Node
s and/or strings, and
+ returns the list of paths. If passed a single Node
, the result
+ is the same as calling str(node)
(see above).
+ The string(s) can have embedded construction variables, which are
+ expanded as usual, using the calling environment's set of
+ variables. The paths can be files or directories, and do not have
+ to exist.
+
+
+env=Environment(VAR="value") +n=File("foo.c") +print(env.GetBuildPath([n, "sub/dir/$VAR"])) +
+ + Would print the following file names: + +
% scons -Q
+['foo.c', 'sub/dir/value']
+scons: `.' is up to date.
+
+
+ There is also a function version of GetBuildPath
which can
+ be called without an Environment
; that uses the default SCons
+ Environment
to do substitution on any string arguments.
+
+
+
+ So far we've seen how SCons handles one-time builds.
+ But one of the main functions of a build tool like SCons
+ is to rebuild only what is necessary
+ when source files change--or, put another way,
+ SCons should not
+ waste time rebuilding things that don't need to be rebuilt.
+ You can see this at work simply by re-invoking SCons
+ after building our simple hello
example:
+
+
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q
+scons: `.' is up to date. +
+
+ The second time it is executed,
+ SCons realizes that the hello
program
+ is up-to-date with respect to the current hello.c
source file,
+ and avoids rebuilding it.
+ You can see this more clearly by naming
+ the hello
program explicitly on the command line:
+
+
%scons -Q hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q hello
+scons: `hello' is up to date. +
+
+ Note that SCons reports "...is up to date"
+ only for target files named explicitly on the command line,
+ to avoid cluttering the output.
+
+
+
+ Another aspect of avoiding unnecessary rebuilds
+ is the fundamental build tool behavior
+ of rebuilding
+ things when an input file changes,
+ so that the built software is up to date.
+ By default,
+ SCons keeps track of this through an
+ MD5 signature
, or checksum, of the contents of each file,
+ although you can easily configure
+ SCons to use the
+ modification times (or time stamps)
+ instead.
+ You can even specify your own Python function
+ for deciding if an input file has changed.
+
+
+ + By default, + SCons keeps track of whether a file has changed + based on an MD5 checksum of the file's contents, + not the file's modification time. + This means that you may be surprised by the + default SCons behavior if you are used to the + Make convention of forcing + a rebuild by updating the file's modification time + (using the touch command, for example): + +
%scons -Q hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +%touch hello.c
+%scons -Q hello
+scons: `hello' is up to date. +
+
+ Even though the file's modification time has changed,
+ SCons realizes that the contents of the
+ hello.c
file have not changed,
+ and therefore that the hello
program
+ need not be rebuilt.
+ This avoids unnecessary rebuilds when,
+ for example, someone rewrites the
+ contents of a file without making a change.
+ But if the contents of the file really do change,
+ then SCons detects the change
+ and rebuilds the program as required:
+
+
%scons -Q hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +% [CHANGE THE CONTENTS OF hello.c] +%scons -Q hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +
+
+ Note that you can, if you wish,
+ specify this default behavior
+ (MD5 signatures) explicitly
+ using the Decider
function as follows:
+
+
+Program('hello.c') +Decider('MD5') +
+
+ You can also use the string 'content'
+ as a synonym for 'MD5'
+ when calling the Decider
function.
+
+
+ + Using MD5 signatures to decide if an input file has changed + has one surprising benefit: + if a source file has been changed + in such a way that the contents of the + rebuilt target file(s) + will be exactly the same as the last time + the file was built, + then any "downstream" target files + that depend on the rebuilt-but-not-changed target + file actually need not be rebuilt. + +
+
+ So if, for example,
+ a user were to only change a comment in a hello.c
file,
+ then the rebuilt hello.o
file
+ would be exactly the same as the one previously built
+ (assuming the compiler doesn't put any build-specific
+ information in the object file).
+ SCons would then realize that it would not
+ need to rebuild the hello
program as follows:
+
+
%scons -Q hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +% [CHANGE A COMMENT IN hello.c] +%scons -Q hello
+cc -o hello.o -c hello.c +scons: `hello' is up to date. +
+
+ In essence, SCons
+ "short-circuits" any dependent builds
+ when it realizes that a target file
+ has been rebuilt to exactly the same file as the last build.
+ This does take some extra processing time
+ to read the contents of the target (hello.o
) file,
+ but often saves time when the rebuild that was avoided
+ would have been time-consuming and expensive.
+
+
+ + If you prefer, you can + configure SCons to use the modification time + of a file, not the file contents, + when deciding if a target needs to be rebuilt. + SCons gives you two ways to use time stamps + to decide if an input file has changed + since the last time a target has been built. + +
+
+ The most familiar way to use time stamps
+ is the way Make does:
+ that is, have SCons decide
+ that a target must be rebuilt
+ if a source file's modification time is
+ newer
+ than the target file.
+ To do this, call the Decider
+ function as follows:
+
+
+Object('hello.c') +Decider('timestamp-newer') +
+ + This makes SCons act like Make + when a file's modification time is updated + (using the touch command, for example): + +
%scons -Q hello.o
+cc -o hello.o -c hello.c +%touch hello.c
+%scons -Q hello.o
+cc -o hello.o -c hello.c +
+
+ And, in fact, because this behavior is the same
+ as the behavior of Make,
+ you can also use the string 'make'
+ as a synonym for 'timestamp-newer'
+ when calling the Decider
function:
+
+
+Object('hello.c') +Decider('make') +
+ + One drawback to using times stamps exactly like Make + is that if an input file's modification time suddenly + becomes older than a target file, + the target file will not be rebuilt. + This can happen if an old copy of a source file is restored + from a backup archive, for example. + The contents of the restored file will likely be different + than they were the last time a dependent target was built, + but the target won't be rebuilt + because the modification time of the source file + is not newer than the target. + +
+
+ Because SCons actually stores information
+ about the source files' time stamps whenever a target is built,
+ it can handle this situation by checking for
+ an exact match of the source file time stamp,
+ instead of just whether or not the source file
+ is newer than the target file.
+ To do this, specify the argument
+ 'timestamp-match'
+ when calling the Decider
function:
+
+
+Object('hello.c') +Decider('timestamp-match') +
+
+ When configured this way,
+ SCons will rebuild a target whenever
+ a source file's modification time has changed.
+ So if we use the touch -t
+ option to change the modification time of
+ hello.c
to an old date (January 1, 1989),
+ SCons will still rebuild the target file:
+
+
%scons -Q hello.o
+cc -o hello.o -c hello.c +%touch -t 198901010000 hello.c
+%scons -Q hello.o
+cc -o hello.o -c hello.c +
+
+ In general, the only reason to prefer
+ timestamp-newer
+ instead of
+ timestamp-match
,
+ would be if you have some specific reason
+ to require this Make-like behavior of
+ not rebuilding a target when an otherwise-modified
+ source file is older.
+
+
+
+ As a performance enhancement,
+ SCons provides a way to use
+ MD5 checksums of file contents
+ but to read those contents
+ only when the file's timestamp has changed.
+ To do this, call the Decider
+ function with 'MD5-timestamp'
+ argument as follows:
+
+
+Program('hello.c') +Decider('MD5-timestamp') +
+
+ So configured, SCons will still behave like
+ it does when using Decider('MD5')
:
+
+
+%scons -Q hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +%touch hello.c
+%scons -Q hello
+scons: `hello' is up to date. +%edit hello.c
+ [CHANGE THE CONTENTS OF hello.c] +%scons -Q hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +
+
+ However, the second call to SCons in the above output,
+ when the build is up-to-date,
+ will have been performed by simply looking at the
+ modification time of the hello.c
file,
+ not by opening it and performing
+ an MD5 checksum calcuation on its contents.
+ This can significantly speed up many up-to-date builds.
+
+
+
+ The only drawback to using
+ Decider('MD5-timestamp')
+ is that SCons will not
+ rebuild a target file if a source file was modified
+ within one second of the last time SCons built the file.
+ While most developers are programming,
+ this isn't a problem in practice,
+ since it's unlikely that someone will have built
+ and then thought quickly enough to make a substantive
+ change to a source file within one second.
+ Certain build scripts or
+ continuous integration tools may, however,
+ rely on the ability to apply changes to files
+ automatically and then rebuild as quickly as possible,
+ in which case use of
+ Decider('MD5-timestamp')
+ may not be appropriate.
+
+
+
+ The different string values that we've passed to
+ the Decider
function are essentially used by SCons
+ to pick one of several specific internal functions
+ that implement various ways of deciding if a dependency
+ (usually a source file)
+ has changed since a target file has been built.
+ As it turns out,
+ you can also supply your own function
+ to decide if a dependency has changed.
+
+
+
+ For example, suppose we have an input file
+ that contains a lot of data,
+ in some specific regular format,
+ that is used to rebuild a lot of different target files,
+ but each target file really only depends on
+ one particular section of the input file.
+ We'd like to have each target file depend on
+ only its section of the input file.
+ However, since the input file may contain a lot of data,
+ we want to open the input file only if its timestamp has changed.
+ This could be done with a custom
+ Decider
function that might look something like this:
+
+
+Program('hello.c') +def decide_if_changed(dependency, target, prev_ni): + if dependency.get_timestamp() != prev_ni.timestamp: + dep = str(dependency) + tgt = str(target) + if specific_part_of_file_has_changed(dep, tgt): + return True + return False +Decider(decide_if_changed) +
+
+ Note that in the function definition,
+ the dependency
+ (input file) is the first argument,
+ and then the target
.
+ Both of these are passed to the functions as
+ SCons Node
objects,
+ which we convert to strings using the Python
+ str()
.
+
+
+
+ The third argument, prev_ni
,
+ is an object that holds the
+ signature or timestamp information
+ that was recorded about the dependency
+ the last time the target was built.
+ A prev_ni
object can hold
+ different information,
+ depending on the type of thing that the
+ dependency
argument represents.
+ For normal files,
+ the prev_ni
object
+ has the following attributes:
+
+
+ The content signature,
+ or MD5 checksum, of the contents of the
+ dependency
+ file the last time the target
was built.
+
+ The size in bytes of the dependency
+ file the last time the target was built.
+
+ The modification time of the dependency
+ file the last time the target
was built.
+
+
+ Note that ignoring some of the arguments
+ in your custom Decider
function
+ is a perfectly normal thing to do,
+ if they don't impact the way you want to
+ decide if the dependency file has changed.
+
+
+
+ Another thing to look out for is the fact that the three
+ attributes above may not be present at the time of the first run.
+ Without any prior build, no targets have been created and no
+ .sconsign
DB file exists yet.
+ So, you should always check whether the
+ prev_ni
attribute in question is available.
+
+
+
+ We finally present a small example for a
+ csig
-based decider function. Note how the
+ signature information for the dependency
file
+ has to get initialized via get_csig
+ during each function call (this is mandatory!).
+
+
+env = Environment() + +def config_file_decider(dependency, target, prev_ni): + import os.path + + # We always have to init the .csig value... + dep_csig = dependency.get_csig() + # .csig may not exist, because no target was built yet... + if 'csig' not in dir(prev_ni): + return True + # Target file may not exist yet + if not os.path.exists(str(target.abspath)): + return True + if dep_csig != prev_ni.csig: + # Some change on source file => update installed one + return True + return False + +def update_file(): + f = open("test.txt","a") + f.write("some line\n") + f.close() + +update_file() + +# Activate our own decider function +env.Decider(config_file_decider) + +env.Install("install","test.txt") +
+
+ The previous examples have all demonstrated calling
+ the global Decider
function
+ to configure all dependency decisions that SCons makes.
+ Sometimes, however, you want to be able to configure
+ different decision-making for different targets.
+ When that's necessary, you can use the
+ env.Decider
+ method to affect only the configuration
+ decisions for targets built with a
+ specific construction environment.
+
+
+ + For example, if we arbitrarily want to build + one program using MD5 checkums + and another using file modification times + from the same source + we might configure it this way: + +
+env1 = Environment(CPPPATH = ['.']) +env2 = env1.Clone() +env2.Decider('timestamp-match') +env1.Program('prog-MD5', 'program1.c') +env2.Program('prog-timestamp', 'program2.c') +
+
+ If both of the programs include the same
+ inc.h
file,
+ then updating the modification time of
+ inc.h
+ (using the touch command)
+ will cause only prog-timestamp
+ to be rebuilt:
+
+
%scons -Q
+cc -o program1.o -c -I. program1.c +cc -o prog-MD5 program1.o +cc -o program2.o -c -I. program2.c +cc -o prog-timestamp program2.o +%touch inc.h
+%scons -Q
+cc -o program2.o -c -I. program2.c +cc -o prog-timestamp program2.o +
+
+ SCons still supports two functions that used to be the
+ primary methods for configuring the
+ decision about whether or not an input file has changed.
+ These functions have been officially deprecated
+ as SCons version 2.0,
+ and their use is discouraged,
+ mainly because they rely on a somewhat
+ confusing distinction between how
+ source files and target files are handled.
+ These functions are documented here mainly in case you
+ encounter them in older SConscript
files.
+
+
+
+ The SourceSignatures
function is fairly straightforward,
+ and supports two different argument values
+ to configure whether source file changes should be decided
+ using MD5 signatures:
+
+
+Program('hello.c') +SourceSignatures('MD5') +
+ + Or using time stamps: + +
+Program('hello.c') +SourceSignatures('timestamp') +
+
+ These are roughly equivalent to specifying
+ Decider('MD5')
+ or
+ Decider('timestamp-match')
,
+ respectively,
+ although it only affects how SCons makes
+ decisions about dependencies on
+ source files--that is,
+ files that are not built from any other files.
+
+
+
+ The TargetSignatures
function
+ specifies how SCons decides
+ when a target file has changed
+ when it is used as a
+ dependency of (input to) another target--that is,
+ the TargetSignatures
function configures
+ how the signatures of "intermediate" target files
+ are used when deciding if a "downstream" target file
+ must be rebuilt.
+ [2]
+
+
+
+ The TargetSignatures
function supports the same
+ 'MD5'
and 'timestamp'
+ argument values that are supported by the SourceSignatures
,
+ with the same meanings, but applied to target files.
+ That is, in the example:
+
+
+Program('hello.c') +TargetSignatures('MD5') +
+
+ The MD5 checksum of the hello.o
target file
+ will be used to decide if it has changed since the last
+ time the "downstream" hello
target file was built.
+ And in the example:
+
+
+Program('hello.c') +TargetSignatures('timestamp') +
+
+ The modification time of the hello.o
target file
+ will be used to decide if it has changed since the last
+ time the "downstream" hello
target file was built.
+
+
+
+ The TargetSignatures
function supports
+ two additional argument values:
+ 'source'
and 'build'
.
+ The 'source'
argument
+ specifies that decisions involving
+ whether target files have changed
+ since a previous build
+ should use the same behavior
+ for the decisions configured for source files
+ (using the SourceSignatures
function).
+ So in the example:
+
+
+Program('hello.c') +TargetSignatures('source') +SourceSignatures('timestamp') +
+ + All files, both targets and sources, + will use modification times + when deciding if an input file + has changed since the last + time a target was built. + +
+
+ Lastly, the 'build'
argument
+ specifies that SCons should examine
+ the build status of a target file
+ and always rebuild a "downstream" target
+ if the target file was itself rebuilt,
+ without re-examining the contents or timestamp
+ of the newly-built target file.
+ If the target file was not rebuilt during
+ this scons
invocation,
+ then the target file will be examined
+ the same way as configured by
+ the SourceSignature
call
+ to decide if it has changed.
+
+
+
+ This mimics the behavior of
+ build signatures
+ in earlier versions of SCons.
+ A build signature
re-combined
+ signatures of all the input files
+ that went into making the target file,
+ so that the target file itself
+ did not need to have its contents read
+ to compute an MD5 signature.
+ This can improve performance for some configurations,
+ but is generally not as effective as using
+ Decider('MD5-timestamp')
.
+
+
+
+ Now suppose that our "Hello, World!" program
+ actually has an #include
line
+ to include the hello.h
file in the compilation:
+
+
+#include <hello.h> +int +main() +{ + printf("Hello, %s!\n", string); +} +
+
+ And, for completeness, the hello.h
file looks like this:
+
+
+#define string "world" + +
+
+ In this case, we want SCons to recognize that,
+ if the contents of the hello.h
file change,
+ the hello
program must be recompiled.
+ To do this, we need to modify the
+ SConstruct
file like so:
+
+
+Program('hello.c', CPPPATH = '.') + +
+
+ The $CPPPATH
value
+ tells SCons to look in the current directory
+ ('.'
)
+ for any files included by C source files
+ (.c
or .h
files).
+ With this assignment in the SConstruct
file:
+
+
%scons -Q hello
+cc -o hello.o -c -I. hello.c +cc -o hello hello.o +%scons -Q hello
+scons: `hello' is up to date. +% [CHANGE THE CONTENTS OF hello.h] +%scons -Q hello
+cc -o hello.o -c -I. hello.c +cc -o hello hello.o +
+
+ First, notice that SCons
+ added the -I.
argument
+ from the $CPPPATH
variable
+ so that the compilation would find the
+ hello.h
file in the local directory.
+
+
+
+ Second, realize that SCons knows that the hello
+ program must be rebuilt
+ because it scans the contents of
+ the hello.c
file
+ for the #include
lines that indicate
+ another file is being included in the compilation.
+ SCons records these as
+ implicit dependencies
+ of the target file,
+ Consequently,
+ when the hello.h
file changes,
+ SCons realizes that the hello.c
file includes it,
+ and rebuilds the resulting hello
program
+ that depends on both the hello.c
and hello.h
files.
+
+
+
+ Like the $LIBPATH
variable,
+ the $CPPPATH
variable
+ may be a list of directories,
+ or a string separated by
+ the system-specific path separation character
+ (':' on POSIX/Linux, ';' on Windows).
+ Either way, SCons creates the
+ right command-line options
+ so that the following example:
+
+
+Program('hello.c', CPPPATH = ['include', '/home/project/inc']) +
+ + Will look like this on POSIX or Linux: + +
% scons -Q hello
+cc -o hello.o -c -Iinclude -I/home/project/inc hello.c
+cc -o hello hello.o
+
+ + And like this on Windows: + +
C:\>scons -Q hello.exe
+cl /Fohello.obj /c hello.c /nologo /Iinclude /I\home\project\inc
+link /nologo /OUT:hello.exe hello.obj
+embedManifestExeCheck(target, source, env)
+
+
+ Scanning each file for #include
lines
+ does take some extra processing time.
+ When you're doing a full build of a large system,
+ the scanning time is usually a very small percentage
+ of the overall time spent on the build.
+ You're most likely to notice the scanning time,
+ however, when you rebuild
+ all or part of a large system:
+ SCons will likely take some extra time to "think about"
+ what must be built before it issues the
+ first build command
+ (or decides that everything is up to date
+ and nothing must be rebuilt).
+
+
+
+
+
+ In practice, having SCons scan files saves time
+ relative to the amount of potential time
+ lost to tracking down subtle problems
+ introduced by incorrect dependencies.
+ Nevertheless, the "waiting time"
+ while SCons scans files can annoy
+ individual developers waiting for their builds to finish.
+ Consequently, SCons lets you cache
+ the implicit dependencies
+ that its scanners find,
+ for use by later builds.
+ You can do this by specifying the
+ --implicit-cache
option on the command line:
+
+
%scons -Q --implicit-cache hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q hello
+scons: `hello' is up to date. +
+
+ If you don't want to specify --implicit-cache
+ on the command line each time,
+ you can make it the default behavior for your build
+ by setting the implicit_cache
option
+ in an SConscript
file:
+
+
+SetOption('implicit_cache', 1) +
+
+ SCons does not cache implicit dependencies like this by default
+ because the --implicit-cache
causes SCons to simply use the implicit
+ dependencies stored during the last run, without any checking
+ for whether or not those dependencies are still correct.
+ Specifically, this means --implicit-cache
instructs SCons
+ to not rebuild "correctly" in the
+ following cases:
+
+
+
+
+ When --implicit-cache
is used, SCons will ignore any changes that
+ may have been made to search paths
+ (like $CPPPATH
or $LIBPATH
,).
+ This can lead to SCons not rebuilding a file if a change to
+ $CPPPATH
would normally cause a different, same-named file from
+ a different directory to be used.
+
+
+
+ When --implicit-cache
is used, SCons will not detect if a
+ same-named file has been added to a directory that is earlier in
+ the search path than the directory in which the file was found
+ last time.
+
+
+
+ When using cached implicit dependencies,
+ sometimes you want to "start fresh"
+ and have SCons re-scan the files
+ for which it previously cached the dependencies.
+ For example,
+ if you have recently installed a new version of
+ external code that you use for compilation,
+ the external header files will have changed
+ and the previously-cached implicit dependencies
+ will be out of date.
+ You can update them by
+ running SCons with the --implicit-deps-changed
option:
+
+
%scons -Q --implicit-deps-changed hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q hello
+scons: `hello' is up to date. +
+ + In this case, SCons will re-scan all of the implicit dependencies + and cache updated copies of the information. + +
+
+ By default when caching dependencies,
+ SCons notices when a file has been modified
+ and re-scans the file for any updated
+ implicit dependency information.
+ Sometimes, however, you may want
+ to force SCons to use the cached implicit dependencies,
+ even if the source files changed.
+ This can speed up a build for example,
+ when you have changed your source files
+ but know that you haven't changed
+ any #include
lines.
+ In this case,
+ you can use the --implicit-deps-unchanged
option:
+
+
%scons -Q --implicit-deps-unchanged hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q hello
+scons: `hello' is up to date. +
+ + In this case, + SCons will assume that the cached implicit + dependencies are correct and + will not bother to re-scan changed files. + For typical builds after small, + incremental changes to source files, + the savings may not be very big, + but sometimes every bit of + improved performance counts. + +
+
+ Sometimes a file depends on another file
+ that is not detected by an SCons scanner.
+ For this situation,
+ SCons allows you to specific explicitly that one file
+ depends on another file,
+ and must be rebuilt whenever that file changes.
+ This is specified using the Depends
method:
+
+
+hello = Program('hello.c') +Depends(hello, 'other_file') +
+%scons -Q hello
+cc -c hello.c -o hello.o +cc -o hello hello.o +%scons -Q hello
+scons: `hello' is up to date. +%edit other_file
+ [CHANGE THE CONTENTS OF other_file] +%scons -Q hello
+cc -c hello.c -o hello.o +cc -o hello hello.o +
+
+ Note that the dependency
+ (the second argument to Depends
)
+ may also be a list of Node objects
+ (for example, as returned by a call to a Builder):
+
+
+hello = Program('hello.c') +goodbye = Program('goodbye.c') +Depends(hello, goodbye) +
+ + in which case the dependency or dependencies + will be built before the target(s): + +
+% scons -Q hello
+cc -c goodbye.c -o goodbye.o
+cc -o goodbye goodbye.o
+cc -c hello.c -o hello.o
+cc -o hello hello.o
+
+ + SCons has built-in scanners for a number of languages. Sometimes + these scanners fail to extract certain implicit dependencies due + to limitations of the scanner implementation. + +
+ + The following example illustrates a case where the built-in C + scanner is unable to extract the implicit dependency on a header + file. + +
+#define FOO_HEADER <foo.h> +#include FOO_HEADER + +int main() { + return FOO; +} +
%scons -Q
+cc -o hello.o -c -I. hello.c +cc -o hello hello.o +% [CHANGE CONTENTS OF foo.h] +%scons -Q
+scons: `.' is up to date. +
+ + Apparently, the scanner does not know about the header dependency. + Being not a full-fledged C preprocessor, the scanner does not + expand the macro. + +
+
+ In these cases, you may also use the compiler to extract the
+ implicit dependencies. ParseDepends
can parse the contents of
+ the compiler output in the style of Make, and explicitly
+ establish all of the listed dependencies.
+
+
+
+ The following example uses ParseDepends
to process a compiler
+ generated dependency file which is generated as a side effect
+ during compilation of the object file:
+
+
+obj = Object('hello.c', CCFLAGS='-MD -MF hello.d', CPPPATH='.') +SideEffect('hello.d', obj) +ParseDepends('hello.d') +Program('hello', obj) +
%scons -Q
+cc -o hello.o -c -MD -MF hello.d -I. hello.c +cc -o hello hello.o +% [CHANGE CONTENTS OF foo.h] +%scons -Q
+cc -o hello.o -c -MD -MF hello.d -I. hello.c +
+
+ Parsing dependencies from a compiler-generated
+ .d
file has a chicken-and-egg problem, that
+ causes unnecessary rebuilds:
+
+
+%scons -Q
+cc -o hello.o -c -MD -MF hello.d -I. hello.c +cc -o hello hello.o +%scons -Q --debug=explain
+scons: rebuilding `hello.o' because `foo.h' is a new dependency +cc -o hello.o -c -MD -MF hello.d -I. hello.c +%scons -Q
+scons: `.' is up to date. +
+
+ In the first pass, the dependency file is generated while the
+ object file is compiled. At that time, SCons does not know about
+ the dependency on foo.h
. In the second pass,
+ the object file is regenerated because foo.h
+ is detected as a new dependency.
+
+
+
+ ParseDepends
immediately reads the specified file at invocation
+ time and just returns if the file does not exist. A dependency
+ file generated during the build process is not automatically
+ parsed again. Hence, the compiler-extracted dependencies are not
+ stored in the signature database during the same build pass. This
+ limitation of ParseDepends
leads to unnecessary recompilations.
+ Therefore, ParseDepends
should only be used if scanners are not
+ available for the employed language or not powerful enough for the
+ specific task.
+
+
+ + Sometimes it makes sense + to not rebuild a program, + even if a dependency file changes. + In this case, + you would tell SCons specifically + to ignore a dependency as follows: + +
+hello_obj=Object('hello.c') +hello = Program(hello_obj) +Ignore(hello_obj, 'hello.h') +
+%scons -Q hello
+cc -c -o hello.o hello.c +cc -o hello hello.o +%scons -Q hello
+scons: `hello' is up to date. +%edit hello.h
+ [CHANGE THE CONTENTS OF hello.h] +%scons -Q hello
+scons: `hello' is up to date. +
+
+ Now, the above example is a little contrived,
+ because it's hard to imagine a real-world situation
+ where you wouldn't want to rebuild hello
+ if the hello.h
file changed.
+ A more realistic example
+ might be if the hello
+ program is being built in a
+ directory that is shared between multiple systems
+ that have different copies of the
+ stdio.h
include file.
+ In that case,
+ SCons would notice the differences between
+ the different systems' copies of stdio.h
+ and would rebuild hello
+ each time you change systems.
+ You could avoid these rebuilds as follows:
+
+
+hello = Program('hello.c', CPPPATH=['/usr/include']) +Ignore(hello, '/usr/include/stdio.h') +
+ Ignore
can also be used to prevent a generated file from being built
+ by default. This is due to the fact that directories depend on
+ their contents. So to ignore a generated file from the default build,
+ you specify that the directory should ignore the generated file.
+ Note that the file will still be built if the user specifically
+ requests the target on scons command line, or if the file is
+ a dependency of another file which is requested and/or is built
+ by default.
+
+hello_obj=Object('hello.c') +hello = Program(hello_obj) +Ignore('.',[hello,hello_obj]) +
%scons -Q
+scons: `.' is up to date. +%scons -Q hello
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q hello
+scons: `hello' is up to date. +
+ + Occasionally, + it may be useful to specify that a certain + file or directory must, if necessary, + be built or created before some other target is built, + but that changes to that file or directory + do not + require that the target itself be rebuilt. + Such a relationship is called an + order-only dependency + because it only affects the order in which + things must be built--the dependency before the target--but + it is not a strict dependency relationship + because the target should not + change in response to changes in the dependent file. + +
+
+ For example, suppose that you want to create a file
+ every time you run a build
+ that identifies the time the build was performed,
+ the version number, etc.,
+ and which is included in every program that you build.
+ The version file's contents will change every build.
+ If you specify a normal dependency relationship,
+ then every program that depends on
+ that file would be rebuilt every time you ran SCons.
+ For example, we could use some Python code in
+ a SConstruct
file to create a new version.c
file
+ with a string containing the current date every time
+ we run SCons,
+ and then link a program with the resulting object file
+ by listing version.c
in the sources:
+
+
+import time + +version_c_text = """ +char *date = "%s"; +""" % time.ctime(time.time()) +open('version.c', 'w').write(version_c_text) + +hello = Program(['hello.c', 'version.c']) +
+
+ If we list version.c
as an actual source file,
+ though, then the version.o
file
+ will get rebuilt every time we run SCons
+ (because the SConstruct
file itself changes
+ the contents of version.c
)
+ and the hello
executable
+ will get re-linked every time
+ (because the version.o
file changes):
+
+
%scons -Q hello
+cc -o hello.o -c hello.c +cc -o version.o -c version.c +cc -o hello hello.o version.o +%sleep 1
+%scons -Q hello
+cc -o version.o -c version.c +cc -o hello hello.o version.o +%sleep 1
+%scons -Q hello
+cc -o version.o -c version.c +cc -o hello hello.o version.o +
+
+ (Note that for the above example to work,
+ we sleep for one second in between each run,
+ so that the SConstruct
file will create a
+ version.c
file with a time string
+ that's one second later than the previous run.)
+
+
+
+ One solution is to use the Requires
function
+ to specify that the version.o
+ must be rebuilt before it is used by the link step,
+ but that changes to version.o
+ should not actually cause the hello
+ executable to be re-linked:
+
+
+import time + +version_c_text = """ +char *date = "%s"; +""" % time.ctime(time.time()) +open('version.c', 'w').write(version_c_text) + +version_obj = Object('version.c') + +hello = Program('hello.c', + LINKFLAGS = str(version_obj[0])) + +Requires(hello, version_obj) +
+
+ Notice that because we can no longer list version.c
+ as one of the sources for the hello
program,
+ we have to find some other way to get it into the link command line.
+ For this example, we're cheating a bit and stuffing the
+ object file name (extracted from version_obj
+ list returned by the Object
call)
+ into the $LINKFLAGS
variable,
+ because $LINKFLAGS
is already included
+ in the $LINKCOM
command line.
+
+
+
+ With these changes,
+ we get the desired behavior of only
+ re-linking the hello
executable
+ when the hello.c
has changed,
+ even though the version.o
is rebuilt
+ (because the SConstruct
file still changes the
+ version.c
contents directly each run):
+
+
%scons -Q hello
+cc -o version.o -c version.c +cc -o hello.o -c hello.c +cc -o hello version.o hello.o +%sleep 1
+%scons -Q hello
+cc -o version.o -c version.c +scons: `hello' is up to date. +%sleep 1
+% [CHANGE THE CONTENTS OF hello.c] +%scons -Q hello
+cc -o version.o -c version.c +cc -o hello.o -c hello.c +cc -o hello version.o hello.o +%sleep 1
+%scons -Q hello
+cc -o version.o -c version.c +scons: `hello' is up to date. +
+
+ How SCons handles dependencies can also be affected
+ by the AlwaysBuild
method.
+ When a file is passed to the AlwaysBuild
method,
+ like so:
+
+
+hello = Program('hello.c') +AlwaysBuild(hello) +
+
+ Then the specified target file (hello
in our example)
+ will always be considered out-of-date and
+ rebuilt whenever that target file is evaluated
+ while walking the dependency graph:
+
+
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q
+cc -o hello hello.o +
+
+ The AlwaysBuild
function has a somewhat misleading name,
+ because it does not actually mean the target file will
+ be rebuilt every single time SCons is invoked.
+ Instead, it means that the target will, in fact,
+ be rebuilt whenever the target file is encountered
+ while evaluating the targets specified on
+ the command line (and their dependencies).
+ So specifying some other target on the command line,
+ a target that does not
+ itself depend on the AlwaysBuild
target,
+ will still be rebuilt only if it's out-of-date
+ with respect to its dependencies:
+
+
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q hello.o
+scons: `hello.o' is up to date. +
[2]
+ This easily-overlooked distinction between
+ how SCons decides if the target itself must be rebuilt
+ and how the target is then used to decide if a different
+ target must be rebuilt is one of the confusing
+ things that has led to the TargetSignatures
+ and SourceSignatures
functions being
+ replaced by the simpler Decider
function.
+
+
+ An environment
+ is a collection of values that
+ can affect how a program executes.
+ SCons distinguishes between three
+ different types of environments
+ that can affect the behavior of SCons itself
+ (subject to the configuration in the SConscript
files),
+ as well as the compilers and other tools it executes:
+
+
+
+ The external environment
+ is the set of variables in the user's environment
+ at the time the user runs SCons.
+ These variables are available within the SConscript
files
+ through the Python os.environ
dictionary.
+ See Section 7.1, “Using Values From the External Environment”, below.
+
+
Construction Environment
+
+ A construction environment
+ is a distinct object created within
+ a SConscript
file and
+ which contains values that
+ affect how SCons decides
+ what action to use to build a target,
+ and even to define which targets
+ should be built from which sources.
+ One of the most powerful features of SCons
+ is the ability to create multiple construction environments
,
+ including the ability to clone a new, customized
+ construction environment
from an existing construction environment
.
+ See Section 7.2, “Construction Environments”, below.
+
+
+
+ An execution environment
+ is the values that SCons sets
+ when executing an external
+ command (such as a compiler or linker)
+ to build one or more targets.
+ Note that this is not the same as
+ the external environment
+ (see above).
+ See Section 7.3, “Controlling the Execution Environment for Issued Commands”, below.
+
+
+
+ Unlike Make, SCons does not automatically
+ copy or import values between different environments
+ (with the exception of explicit clones of construction environments
,
+ which inherit values from their parent).
+ This is a deliberate design choice
+ to make sure that builds are,
+ by default, repeatable regardless of
+ the values in the user's external environment.
+ This avoids a whole class of problems with builds
+ where a developer's local build works
+ because a custom variable setting
+ causes a different compiler or build option to be used,
+ but the checked-in change breaks the official build
+ because it uses different environment variable settings.
+
+
+
+ Note that the SConscript
writer can
+ easily arrange for variables to be
+ copied or imported between environments,
+ and this is often very useful
+ (or even downright necessary)
+ to make it easy for developers
+ to customize the build in appropriate ways.
+ The point is not
+ that copying variables between different environments
+ is evil and must always be avoided.
+ Instead, it should be up to the
+ implementer of the build system
+ to make conscious choices
+ about how and when to import
+ a variable from one environment to another,
+ making informed decisions about
+ striking the right balance
+ between making the build
+ repeatable on the one hand
+ and convenient to use on the other.
+
+
+
+ The external environment
+ variable settings that
+ the user has in force
+ when executing SCons
+ are available through the normal Python
+ os.environ
+ dictionary.
+ This means that you must add an
+ import os
statement
+ to any SConscript
file
+ in which you want to use
+ values from the user's external environment.
+
+
+import os +
+
+ More usefully, you can use the
+ os.environ
+ dictionary in your SConscript
+ files to initialize construction environments
+ with values from the user's external environment.
+ See the next section,
+ Section 7.2, “Construction Environments”,
+ for information on how to do this.
+
+
+
+ It is rare that all of the software in a large,
+ complicated system needs to be built the same way.
+ For example, different source files may need different options
+ enabled on the command line,
+ or different executable programs need to be linked
+ with different libraries.
+ SCons accommodates these different build
+ requirements by allowing you to create and
+ configure multiple construction environments
+ that control how the software is built.
+ A construction environment
is an object
+ that has a number of associated
+ construction variables
, each with a name and a value.
+ (A construction environment also has an attached
+ set of Builder
methods,
+ about which we'll learn more later.)
+
+
+
+ A construction environment
is created by the Environment
method:
+
+
+env = Environment() +
+
+ By default, SCons initializes every
+ new construction environment
+ with a set of construction variables
+ based on the tools that it finds on your system,
+ plus the default set of builder methods
+ necessary for using those tools.
+ The construction variables
+ are initialized with values describing
+ the C compiler,
+ the Fortran compiler,
+ the linker,
+ etc.,
+ as well as the command lines to invoke them.
+
+
+
+ When you initialize a construction environment
+ you can set the values of the
+ environment's construction variables
+ to control how a program is built.
+ For example:
+
+
+ env = Environment(CC = 'gcc', + CCFLAGS = '-O2') + + env.Program('foo.c') +
+
+ The construction environment in this example
+ is still initialized with the same default
+ construction variable values,
+ except that the user has explicitly specified use of the
+ GNU C compiler gcc,
+ and further specifies that the -O2
+ (optimization level two)
+ flag should be used when compiling the object file.
+ In other words, the explicit initializations of
+ $CC
and $CCFLAGS
+ override the default values in the newly-created
+ construction environment.
+ So a run from this example would look like:
+
+
% scons -Q
+gcc -o foo.o -c -O2 foo.c
+gcc -o foo foo.o
+
+ + You can fetch individual construction variables + using the normal syntax + for accessing individual named items in a Python dictionary: + +
+env = Environment() +print("CC is: %s"%env['CC']) +
+
+ This example SConstruct
file doesn't build anything,
+ but because it's actually a Python script,
+ it will print the value of $CC
for us:
+
+
% scons -Q
+CC is: cc
+scons: `.' is up to date.
+
+
+ A construction environment, however,
+ is actually an object with associated methods, etc.
+ If you want to have direct access to only the
+ dictionary of construction variables,
+ you can fetch this using the Dictionary
method:
+
+
+env = Environment(FOO = 'foo', BAR = 'bar') +dict = env.Dictionary() +for key in ['OBJSUFFIX', 'LIBSUFFIX', 'PROGSUFFIX']: + print("key = %s, value = %s" % (key, dict[key])) +
+
+ This SConstruct
file
+ will print the specified dictionary items for us on POSIX
+ systems as follows:
+
+
% scons -Q
+key = OBJSUFFIX, value = .o
+key = LIBSUFFIX, value = .a
+key = PROGSUFFIX, value =
+scons: `.' is up to date.
+
+ + And on Windows: + +
C:\>scons -Q
+key = OBJSUFFIX, value = .obj
+key = LIBSUFFIX, value = .lib
+key = PROGSUFFIX, value = .exe
+scons: `.' is up to date.
+
+ + If you want to loop and print the values of + all of the construction variables in a construction environment, + the Python code to do that in sorted order might look something like: + +
+env = Environment() +for item in sorted(env.Dictionary().items()): + print("construction variable = '%s', value = '%s'" % item) +
+
+ Another way to get information from
+ a construction environment
+ is to use the subst
method
+ on a string containing $
expansions
+ of construction variable names.
+ As a simple example,
+ the example from the previous
+ section that used
+ env['CC']
+ to fetch the value of $CC
+ could also be written as:
+
+
+env = Environment() +print("CC is: %s"%env.subst('$CC')) +
+
+ One advantage of using
+ subst
to expand strings is
+ that construction variables
+ in the result get re-expanded until
+ there are no expansions left in the string.
+ So a simple fetch of a value like
+ $CCCOM
:
+
+
+env = Environment(CCFLAGS = '-DFOO') +print("CCCOM is: %s"%env['CCCOM']) +
+
+ Will print the unexpanded value of $CCCOM
,
+ showing us the construction
+ variables that still need to be expanded:
+
+
+% scons -Q
+CCCOM is: $CC $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES
+scons: `.' is up to date.
+
+
+ Calling the subst
method on $CCOM
,
+ however:
+
+
+env = Environment(CCFLAGS = '-DFOO') +print("CCCOM is: %s"%env.subst('$CCCOM')) +
+
+ Will recursively expand all of
+ the construction variables prefixed
+ with $
(dollar signs),
+ showing us the final output:
+
+
+% scons -Q
+CCCOM is: gcc -DFOO -c -o
+scons: `.' is up to date.
+
+
+ Note that because we're not expanding this
+ in the context of building something
+ there are no target or source files
+ for $TARGET
and $SOURCES
to expand.
+
+
+
+ If a problem occurs when expanding a construction variable,
+ by default it is expanded to ''
+ (a null string), and will not cause scons to fail.
+
+env = Environment() +print("value is: %s"%env.subst( '->$MISSING<-' )) +
% scons -Q
+value is: -><-
+scons: `.' is up to date.
+
+ This default behaviour can be changed using the AllowSubstExceptions
+ function.
+ When a problem occurs with a variable expansion it generates
+ an exception, and the AllowSubstExceptions
function controls
+ which of these exceptions are actually fatal and which are
+ allowed to occur safely. By default, NameError
and IndexError
+ are the two exceptions that are allowed to occur: so instead of
+ causing scons to fail, these are caught, the variable expanded to
+ ''
+ and scons execution continues.
+ To require that all construction variable names exist, and that
+ indexes out of range are not allowed, call AllowSubstExceptions
+ with no extra arguments.
+
+AllowSubstExceptions() +env = Environment() +print("value is: %s"%env.subst( '->$MISSING<-' )) +
% scons -Q
+
+scons: *** NameError `MISSING' trying to evaluate `$MISSING'
+File "/home/my/project/SConstruct", line 3, in <module>
+
+ This can also be used to allow other exceptions that might occur,
+ most usefully with the ${...}
construction
+ variable syntax. For example, this would allow zero-division to
+ occur in a variable expansion in addition to the default exceptions
+ allowed
+
+AllowSubstExceptions(IndexError, NameError, ZeroDivisionError) +env = Environment() +print("value is: %s"%env.subst( '->${1 / 0}<-' )) +
% scons -Q
+value is: -><-
+scons: `.' is up to date.
+
+ If AllowSubstExceptions
is called multiple times, each call
+ completely overwrites the previous list of allowed exceptions.
+
+
+ All of the Builder
functions that we've introduced so far,
+ like Program
and Library
,
+ actually use a default construction environment
+ that contains settings
+ for the various compilers
+ and other tools that
+ SCons configures by default,
+ or otherwise knows about
+ and has discovered on your system.
+ The goal of the default construction environment
+ is to make many configurations to "just work"
+ to build software using
+ readily available tools
+ with a minimum of configuration changes.
+
+
+
+ You can, however, control the settings
+ in the default construction environment
+ by using the DefaultEnvironment
function
+ to initialize various settings:
+
+
+DefaultEnvironment(CC = '/usr/local/bin/gcc') +
+
+ When configured as above,
+ all calls to the Program
+ or Object
Builder
+ will build object files with the
+ /usr/local/bin/gcc
+ compiler.
+
+
+
+ Note that the DefaultEnvironment
function
+ returns the initialized
+ default construction environment object,
+ which can then be manipulated like any
+ other construction environment.
+ So the following
+ would be equivalent to the
+ previous example,
+ setting the $CC
+ variable to /usr/local/bin/gcc
+ but as a separate step after
+ the default construction environment has been initialized:
+
+
+env = DefaultEnvironment() +env['CC'] = '/usr/local/bin/gcc' +
+
+ One very common use of the DefaultEnvironment
function
+ is to speed up SCons initialization.
+ As part of trying to make most default
+ configurations "just work,"
+ SCons will actually
+ search the local system for installed
+ compilers and other utilities.
+ This search can take time,
+ especially on systems with
+ slow or networked file systems.
+ If you know which compiler(s) and/or
+ other utilities you want to configure,
+ you can control the search
+ that SCons performs
+ by specifying some specific
+ tool modules with which to
+ initialize the default construction environment:
+
+
+env = DefaultEnvironment(tools = ['gcc', 'gnulink'], + CC = '/usr/local/bin/gcc') +
+
+ So the above example would tell SCons
+ to explicitly configure the default environment
+ to use its normal GNU Compiler and GNU Linker settings
+ (without having to search for them,
+ or any other utilities for that matter),
+ and specifically to use the compiler found at
+ /usr/local/bin/gcc
.
+
+
+
+ The real advantage of construction environments
+ is that you can create as many different construction
+ environments as you need,
+ each tailored to a different way to build
+ some piece of software or other file.
+ If, for example, we need to build
+ one program with the -O2
flag
+ and another with the -g
(debug) flag,
+ we would do this like so:
+
+
+opt = Environment(CCFLAGS = '-O2') +dbg = Environment(CCFLAGS = '-g') + +opt.Program('foo', 'foo.c') + +dbg.Program('bar', 'bar.c') +
% scons -Q
+cc -o bar.o -c -g bar.c
+cc -o bar bar.o
+cc -o foo.o -c -O2 foo.c
+cc -o foo foo.o
+
+
+ We can even use multiple construction environments to build
+ multiple versions of a single program.
+ If you do this by simply trying to use the
+ Program
builder with both environments, though,
+ like this:
+
+
+opt = Environment(CCFLAGS = '-O2') +dbg = Environment(CCFLAGS = '-g') + +opt.Program('foo', 'foo.c') + +dbg.Program('foo', 'foo.c') +
+ + Then SCons generates the following error: + +
% scons -Q
+
+scons: *** Two environments with different actions were specified for the same target: foo.o
+File "/home/my/project/SConstruct", line 6, in <module>
+
+
+ This is because the two Program
calls have
+ each implicitly told SCons to generate an object file named
+ foo.o
,
+ one with a $CCFLAGS
value of
+ -O2
+ and one with a $CCFLAGS
value of
+ -g
.
+ SCons can't just decide that one of them
+ should take precedence over the other,
+ so it generates the error.
+ To avoid this problem,
+ we must explicitly specify
+ that each environment compile
+ foo.c
+ to a separately-named object file
+ using the Object
builder, like so:
+
+
+opt = Environment(CCFLAGS = '-O2') +dbg = Environment(CCFLAGS = '-g') + +o = opt.Object('foo-opt', 'foo.c') +opt.Program(o) + +d = dbg.Object('foo-dbg', 'foo.c') +dbg.Program(d) +
+
+ Notice that each call to the Object
builder
+ returns a value,
+ an internal SCons object that
+ represents the object file that will be built.
+ We then use that object
+ as input to the Program
builder.
+ This avoids having to specify explicitly
+ the object file name in multiple places,
+ and makes for a compact, readable
+ SConstruct
file.
+ Our SCons output then looks like:
+
+
% scons -Q
+cc -o foo-dbg.o -c -g foo.c
+cc -o foo-dbg foo-dbg.o
+cc -o foo-opt.o -c -O2 foo.c
+cc -o foo-opt foo-opt.o
+
+
+ Sometimes you want more than one construction environment
+ to share the same values for one or more variables.
+ Rather than always having to repeat all of the common
+ variables when you create each construction environment,
+ you can use the Clone
method
+ to create a copy of a construction environment.
+
+
+
+ Like the Environment
call that creates a construction environment,
+ the Clone
method takes construction variable
assignments,
+ which will override the values in the copied construction environment.
+ For example, suppose we want to use gcc
+ to create three versions of a program,
+ one optimized, one debug, and one with neither.
+ We could do this by creating a "base" construction environment
+ that sets $CC
to gcc,
+ and then creating two copies,
+ one which sets $CCFLAGS
for optimization
+ and the other which sets $CCFLAGS
for debugging:
+
+
+env = Environment(CC = 'gcc') +opt = env.Clone(CCFLAGS = '-O2') +dbg = env.Clone(CCFLAGS = '-g') + +env.Program('foo', 'foo.c') + +o = opt.Object('foo-opt', 'foo.c') +opt.Program(o) + +d = dbg.Object('foo-dbg', 'foo.c') +dbg.Program(d) +
+ + Then our output would look like: + +
% scons -Q
+gcc -o foo.o -c foo.c
+gcc -o foo foo.o
+gcc -o foo-dbg.o -c -g foo.c
+gcc -o foo-dbg foo-dbg.o
+gcc -o foo-opt.o -c -O2 foo.c
+gcc -o foo-opt foo-opt.o
+
+
+ You can replace existing construction variable values
+ using the Replace
method:
+
+
+env = Environment(CCFLAGS = '-DDEFINE1') +env.Replace(CCFLAGS = '-DDEFINE2') +env.Program('foo.c') +
+
+ The replacing value
+ (-DDEFINE2
in the above example)
+ completely replaces the value in the
+ construction environment:
+
+
% scons -Q
+cc -o foo.o -c -DDEFINE2 foo.c
+cc -o foo foo.o
+
+
+ You can safely call Replace
+ for construction variables that
+ don't exist in the construction environment:
+
+
+env = Environment() +env.Replace(NEW_VARIABLE = 'xyzzy') +print("NEW_VARIABLE = %s"%env['NEW_VARIABLE']) +
+ + In this case, + the construction variable simply + gets added to the construction environment: + +
% scons -Q
+NEW_VARIABLE = xyzzy
+scons: `.' is up to date.
+
+ + Because the variables + aren't expanded until the construction environment + is actually used to build the targets, + and because SCons function and method calls + are order-independent, + the last replacement "wins" + and is used to build all targets, + regardless of the order in which + the calls to Replace() are + interspersed with calls to + builder methods: + +
+env = Environment(CCFLAGS = '-DDEFINE1') +print("CCFLAGS = %s"%env['CCFLAGS']) +env.Program('foo.c') + +env.Replace(CCFLAGS = '-DDEFINE2') +print("CCFLAGS = %s"%env['CCFLAGS']) +env.Program('bar.c') +
+
+ The timing of when the replacement
+ actually occurs relative
+ to when the targets get built
+ becomes apparent
+ if we run scons
without the -Q
+ option:
+
+
% scons
+scons: Reading SConscript files ...
+CCFLAGS = -DDEFINE1
+CCFLAGS = -DDEFINE2
+scons: done reading SConscript files.
+scons: Building targets ...
+cc -o bar.o -c -DDEFINE2 bar.c
+cc -o bar bar.o
+cc -o foo.o -c -DDEFINE2 foo.c
+cc -o foo foo.o
+scons: done building targets.
+
+
+ Because the replacement occurs while
+ the SConscript
files are being read,
+ the $CCFLAGS
+ variable has already been set to
+ -DDEFINE2
+ by the time the foo.o
target is built,
+ even though the call to the Replace
+ method does not occur until later in
+ the SConscript
file.
+
+
+
+ Sometimes it's useful to be able to specify
+ that a construction variable should be
+ set to a value only if the construction environment
+ does not already have that variable defined
+ You can do this with the SetDefault
method,
+ which behaves similarly to the set_default
+ method of Python dictionary objects:
+
+
+env.SetDefault(SPECIAL_FLAG = '-extra-option') +
+
+ This is especially useful
+ when writing your own Tool
modules
+ to apply variables to construction environments.
+
+
+
+
+ You can append a value to
+ an existing construction variable
+ using the Append
method:
+
+
+env = Environment(CCFLAGS = ['-DMY_VALUE']) +env.Append(CCFLAGS = ['-DLAST']) +env.Program('foo.c') +
+
+ SCons then supplies both the -DMY_VALUE
and
+ -DLAST
flags when compiling the object file:
+
+
% scons -Q
+cc -o foo.o -c -DMY_VALUE -DLAST foo.c
+cc -o foo foo.o
+
+
+ If the construction variable doesn't already exist,
+ the Append
method will create it:
+
+
+env = Environment() +env.Append(NEW_VARIABLE = 'added') +print("NEW_VARIABLE = %s"%env['NEW_VARIABLE']) +
+ + Which yields: + +
% scons -Q
+NEW_VARIABLE = added
+scons: `.' is up to date.
+
+
+ Note that the Append
function tries to be "smart"
+ about how the new value is appended to the old value.
+ If both are strings, the previous and new strings
+ are simply concatenated.
+ Similarly, if both are lists,
+ the lists are concatenated.
+ If, however, one is a string and the other is a list,
+ the string is added as a new element to the list.
+
+
+
+ Some times it's useful to add a new value
+ only if the existing construction variable
+ doesn't already contain the value.
+ This can be done using the AppendUnique
method:
+
+
+env.AppendUnique(CCFLAGS=['-g']) +
+
+ In the above example,
+ the -g
would be added
+ only if the $CCFLAGS
variable
+ does not already contain a -g
value.
+
+
+
+ You can append a value to the beginning of
+ an existing construction variable
+ using the Prepend
method:
+
+
+env = Environment(CCFLAGS = ['-DMY_VALUE']) +env.Prepend(CCFLAGS = ['-DFIRST']) +env.Program('foo.c') +
+
+ SCons then supplies both the -DFIRST
and
+ -DMY_VALUE
flags when compiling the object file:
+
+
% scons -Q
+cc -o foo.o -c -DFIRST -DMY_VALUE foo.c
+cc -o foo foo.o
+
+
+ If the construction variable doesn't already exist,
+ the Prepend
method will create it:
+
+
+env = Environment() +env.Prepend(NEW_VARIABLE = 'added') +print("NEW_VARIABLE = %s"%env['NEW_VARIABLE']) +
+ + Which yields: + +
% scons -Q
+NEW_VARIABLE = added
+scons: `.' is up to date.
+
+
+ Like the Append
function,
+ the Prepend
function tries to be "smart"
+ about how the new value is appended to the old value.
+ If both are strings, the previous and new strings
+ are simply concatenated.
+ Similarly, if both are lists,
+ the lists are concatenated.
+ If, however, one is a string and the other is a list,
+ the string is added as a new element to the list.
+
+
+
+ Some times it's useful to add a new value
+ to the beginning of a construction variable
+ only if the existing value
+ doesn't already contain the to-be-added value.
+ This can be done using the PrependUnique
method:
+
+
+env.PrependUnique(CCFLAGS=['-g']) +
+
+ In the above example,
+ the -g
would be added
+ only if the $CCFLAGS
variable
+ does not already contain a -g
value.
+
+
+
+ When SCons builds a target file,
+ it does not execute the commands with
+ the same external environment
+ that you used to execute SCons.
+ Instead, it uses the dictionary
+ stored in the $ENV
construction variable
+ as the external environment
+ for executing commands.
+
+
+
+ The most important ramification of this behavior
+ is that the PATH
environment variable,
+ which controls where the operating system
+ will look for commands and utilities,
+ is not the same as in the external environment
+ from which you called SCons.
+ This means that SCons will not, by default,
+ necessarily find all of the tools
+ that you can execute from the command line.
+
+
+
+ The default value of the PATH
environment variable
+ on a POSIX system
+ is /usr/local/bin:/bin:/usr/bin
.
+ The default value of the PATH
environment variable
+ on a Windows system comes from the Windows registry
+ value for the command interpreter.
+ If you want to execute any commands--compilers, linkers, etc.--that
+ are not in these default locations,
+ you need to set the PATH
value
+ in the $ENV
dictionary
+ in your construction environment.
+
+
+ + The simplest way to do this is to initialize explicitly + the value when you create the construction environment; + this is one way to do that: + +
+path = ['/usr/local/bin', '/bin', '/usr/bin'] +env = Environment(ENV = {'PATH' : path}) +
+
+ Assign a dictionary to the $ENV
+ construction variable in this way
+ completely resets the external environment
+ so that the only variable that will be
+ set when external commands are executed
+ will be the PATH
value.
+ If you want to use the rest of
+ the values in $ENV
and only
+ set the value of PATH
,
+ the most straightforward way is probably:
+
+
+env['ENV']['PATH'] = ['/usr/local/bin', '/bin', '/usr/bin'] +
+
+ Note that SCons does allow you to define
+ the directories in the PATH
in a string,
+ separated by the pathname-separator character
+ for your system (':' on POSIX systems, ';' on Windows):
+
+
+env['ENV']['PATH'] = '/usr/local/bin:/bin:/usr/bin' +
+
+ But doing so makes your SConscript
file less portable,
+ (although in this case that may not be a huge concern
+ since the directories you list are likely system-specific, anyway).
+
+
+
+ You may want to propagate the external PATH
+ to the execution environment for commands.
+ You do this by initializing the PATH
+ variable with the PATH
value from
+ the os.environ
+ dictionary,
+ which is Python's way of letting you
+ get at the external environment:
+
+
+import os +env = Environment(ENV = {'PATH' : os.environ['PATH']}) +
+
+ Alternatively, you may find it easier
+ to just propagate the entire external
+ environment to the execution environment
+ for commands.
+ This is simpler to code than explicity
+ selecting the PATH
value:
+
+
+import os +env = Environment(ENV = os.environ) +
+
+ Either of these will guarantee that
+ SCons will be able to execute
+ any command that you can execute from the command line.
+ The drawback is that the build can behave
+ differently if it's run by people with
+ different PATH
values in their environment--for example,
+ if both the /bin
and
+ /usr/local/bin
directories
+ have different cc commands,
+ then which one will be used to compile programs
+ will depend on which directory is listed
+ first in the user's PATH
variable.
+
+
+
+ One of the most common requirements
+ for manipulating a variable in the execution environment
+ is to add one or more custom directories to a search
+ like the $PATH
variable on Linux or POSIX systems,
+ or the %PATH%
variable on Windows,
+ so that a locally-installed compiler or other utility
+ can be found when SCons tries to execute it to update a target.
+ SCons provides PrependENVPath
and AppendENVPath
functions
+ to make adding things to execution variables convenient.
+ You call these functions by specifying the variable
+ to which you want the value added,
+ and then value itself.
+ So to add some /usr/local
directories
+ to the $PATH
and $LIB
variables,
+ you might:
+
+
+env = Environment(ENV = os.environ) +env.PrependENVPath('PATH', '/usr/local/bin') +env.AppendENVPath('LIB', '/usr/local/lib') +
+
+ Note that the added values are strings,
+ and if you want to add multiple directories to
+ a variable like $PATH
,
+ you must include the path separate character
+ (:
on Linux or POSIX,
+ ;
on Windows)
+ in the string.
+
+
+ Normally when using a tool from the construction environment,
+ several different search locations are checked by default.
+ This includes the Scons/Tools/
directory
+ inbuilt to scons and the directory site_scons/site_tools
+ relative to the root SConstruct file.
+
+# Builtin tool or tool located within site_tools +env = Environment(tools = ['SomeTool']) +env.SomeTool(targets, sources) + +# The search locations would include by default +SCons/Tool/SomeTool.py +SCons/Tool/SomeTool/__init__.py +./site_scons/site_tools/SomeTool.py +./site_scons/site_tools/SomeTool/__init__.py +
+ In some cases you may want to specify a different location to search for tools. + The Environment constructor contains an option for this called toolpath + This can be used to add additional search directories. +
+# Tool located within the toolpath directory option +env = Environment(tools = ['SomeTool'], toolpath = ['/opt/SomeToolPath', '/opt/SomeToolPath2']) +env.SomeTool(targets, sources) + +# The search locations in this example would include: +/opt/SomeToolPath/SomeTool.py +/opt/SomeToolPath/SomeTool/__init__.py +/opt/SomeToolPath2/SomeTool.py +/opt/SomeToolPath2/SomeTool/__init__.py +SCons/Tool/SomeTool.py +SCons/Tool/SomeTool/__init__.py +./site_scons/site_tools/SomeTool.py +./site_scons/site_tools/SomeTool/__init__.py +
+ SCons 3.0 now supports the ability for a Builder to be located + within a sub-directory / sub-package of the toolpath. + This is similar to namespacing within python. + With nested or namespaced tools we can use the dot notation + to specify a sub-directory that the tool is located under. +
+# namespaced target +env = Environment(tools = ['SubDir1.SubDir2.SomeTool'], toolpath = ['/opt/SomeToolPath']) +env.SomeTool(targets, sources) + +# With this example the search locations would include +/opt/SomeToolPath/SubDir1/SubDir2/SomeTool.py +/opt/SomeToolPath/SubDir1/SubDir2/SomeTool/__init__.py +SCons/Tool/SubDir1/SubDir2/SomeTool.py +SCons/Tool/SubDir1/SubDir2/SomeTool/__init__.py +./site_scons/site_tools/SubDir1/SubDir2/SomeTool.py +./site_scons/site_tools/SubDir1/SubDir2/SomeTool/__init__.py +
+ For python2 It's important to note when creating tools within sub-directories, + there needs to be a __init__.py file within each directory. + This file can just be empty. + This is the same constraint used by python when loading modules + from within sub-directories (packages). + For python3 this appears to be no longer a requirement. +
+ If we want to access tools externally to scons on the sys.path + (one example would be tools installed via the pip package manager) + One way to do this is to use sys.path with the toolpath. + + One thing to watch out for with this approach is that sys.path + can sometimes contains paths to .egg files instead of directories. + So we need to filter those out with this approach. +
+# namespaced target using sys.path within toolpath + +searchpaths = [] +for item in sys.path: + if os.path.isdir(item): searchpaths.append(item) + +env = Environment(tools = ['someinstalledpackage.SomeTool'], toolpath = searchpaths) +env.SomeTool(targets, sources) +
+ By using sys.path with the toolpath argument + and by using the nested syntax we can have scons search + packages installed via pip for Tools. +
+# For Windows based on the python version and install directory, this may be something like +C:\Python35\Lib\site-packages\someinstalledpackage\SomeTool.py +C:\Python35\Lib\site-packages\someinstalledpackage\SomeTool\__init__.py + +# For Linux this could be something like: +/usr/lib/python3/dist-packages/someinstalledpackage/SomeTool.py +/usr/lib/python3/dist-packages/someinstalledpackage/SomeTool/__init__.py +
+ In some cases you may want to use a tool + located within a installed external pip package. + This is possible by the use of sys.path with the toolpath. + However in that situation you need to provide a prefix to the toolname + to indicate where it is located within sys.path +
+searchpaths = [] +for item in sys.path: + if os.path.isdir(item): searchpaths.append(item) +env = Environment(tools = ['tools_example.subdir1.subdir2.SomeTool'], toolpath = searchpaths) +env.SomeTool(targets, sources) +
+ To avoid the use of a prefix within the name of the tool or filtering sys.path for directories,
+ we can use the PyPackageDir(modulename)
function to locate the directory of the python package.
+ PyPackageDir
returns a Dir object which represents the path of the directory
+ for the python package / module specified as a parameter.
+
+# namespaced target using sys.path +env = Environment(tools = ['SomeTool'], toolpath = [PyPackageDir('tools_example.subdir1.subdir2')]) +env.SomeTool(targets, sources) +
+ This chapter describes the MergeFlags
, ParseFlags
, and ParseConfig
methods of a construction environment
.
+
+
+ SCons construction environments have a MergeFlags
method
+ that merges a dictionary of values into the construction environment.
+ MergeFlags
treats each value in the dictionary
+ as a list of options such as one might pass to a command
+ (such as a compiler or linker).
+ MergeFlags
will not duplicate an option
+ if it already exists in the construction environment variable.
+
+
+
+ MergeFlags
tries to be intelligent about merging options.
+ When merging options to any variable
+ whose name ends in PATH
,
+ MergeFlags
keeps the leftmost occurrence of the option,
+ because in typical lists of directory paths,
+ the first occurrence "wins."
+ When merging options to any other variable name,
+ MergeFlags
keeps the rightmost occurrence of the option,
+ because in a list of typical command-line options,
+ the last occurrence "wins."
+
+
+env = Environment() +env.Append(CCFLAGS = '-option -O3 -O1') +flags = { 'CCFLAGS' : '-whatever -O3' } +env.MergeFlags(flags) +print env['CCFLAGS'] +
% scons -Q
+['-option', '-O1', '-whatever', '-O3']
+scons: `.' is up to date.
+
+
+ Note that the default value for $CCFLAGS
+
+ is an internal SCons object
+ which automatically converts
+ the options we specified as a string into a list.
+
+
+env = Environment() +env.Append(CPPPATH = ['/include', '/usr/local/include', '/usr/include']) +flags = { 'CPPPATH' : ['/usr/opt/include', '/usr/local/include'] } +env.MergeFlags(flags) +print env['CPPPATH'] +
% scons -Q
+['/include', '/usr/local/include', '/usr/include', '/usr/opt/include']
+scons: `.' is up to date.
+
+
+ Note that the default value for $CPPPATH
+
+ is a normal Python list,
+ so we must specify its values as a list
+ in the dictionary we pass to the MergeFlags
function.
+
+
+
+ If MergeFlags
is passed anything other than a dictionary,
+ it calls the ParseFlags
method to convert it into a dictionary.
+
+
+env = Environment() +env.Append(CCFLAGS = '-option -O3 -O1') +env.Append(CPPPATH = ['/include', '/usr/local/include', '/usr/include']) +env.MergeFlags('-whatever -I/usr/opt/include -O3 -I/usr/local/include') +print env['CCFLAGS'] +print env['CPPPATH'] +
% scons -Q
+['-option', '-O1', '-whatever', '-O3']
+['/include', '/usr/local/include', '/usr/include', '/usr/opt/include']
+scons: `.' is up to date.
+
+
+ In the combined example above,
+ ParseFlags
has sorted the options into their corresponding variables
+ and returned a dictionary for MergeFlags
to apply
+ to the construction variables
+ in the specified construction environment.
+
+
+ + SCons has a bewildering array of construction variables + for different types of options when building programs. + Sometimes you may not know exactly which variable + should be used for a particular option. + +
+
+ SCons construction environments have a ParseFlags
method
+ that takes a set of typical command-line options
+ and distributes them into the appropriate construction variables.
+ Historically, it was created to support the ParseConfig
method,
+ so it focuses on options used by the GNU Compiler Collection (GCC)
+ for the C and C++ toolchains.
+
+
+
+ ParseFlags
returns a dictionary containing the options
+ distributed into their respective construction variables.
+ Normally, this dictionary would be passed to MergeFlags
+ to merge the options into a construction environment
,
+ but the dictionary can be edited if desired to provide
+ additional functionality.
+ (Note that if the flags are not going to be edited,
+ calling MergeFlags
with the options directly
+ will avoid an additional step.)
+
+
+env = Environment() +d = env.ParseFlags("-I/opt/include -L/opt/lib -lfoo") +for k,v in sorted(d.items()): + if v: + print k, v +env.MergeFlags(d) +env.Program('f1.c') +
% scons -Q
+CPPPATH ['/opt/include']
+LIBPATH ['/opt/lib']
+LIBS ['foo']
+cc -o f1.o -c -I/opt/include f1.c
+cc -o f1 f1.o -L/opt/lib -lfoo
+
+ + Note that if the options are limited to generic types + like those above, + they will be correctly translated for other platform types: + +
C:\>scons -Q
+CPPPATH ['/opt/include']
+LIBPATH ['/opt/lib']
+LIBS ['foo']
+cl /Fof1.obj /c f1.c /nologo /I\opt\include
+link /nologo /OUT:f1.exe /LIBPATH:\opt\lib foo.lib f1.obj
+embedManifestExeCheck(target, source, env)
+
+
+ Since the assumption is that the flags are used for the GCC toolchain,
+ unrecognized flags are placed in $CCFLAGS
+ so they will be used for both C and C++ compiles:
+
+
+env = Environment() +d = env.ParseFlags("-whatever") +for k,v in sorted(d.items()): + if v: + print k, v +env.MergeFlags(d) +env.Program('f1.c') +
% scons -Q
+CCFLAGS -whatever
+cc -o f1.o -c -whatever f1.c
+cc -o f1 f1.o
+
+
+ ParseFlags
will also accept a (recursive) list of strings as input;
+ the list is flattened before the strings are processed:
+
+
+env = Environment() +d = env.ParseFlags(["-I/opt/include", ["-L/opt/lib", "-lfoo"]]) +for k,v in sorted(d.items()): + if v: + print k, v +env.MergeFlags(d) +env.Program('f1.c') +
% scons -Q
+CPPPATH ['/opt/include']
+LIBPATH ['/opt/lib']
+LIBS ['foo']
+cc -o f1.o -c -I/opt/include f1.c
+cc -o f1 f1.o -L/opt/lib -lfoo
+
+ + If a string begins with a "!" (an exclamation mark, often called a bang), + the string is passed to the shell for execution. + The output of the command is then parsed: + +
+env = Environment() +d = env.ParseFlags(["!echo -I/opt/include", "!echo -L/opt/lib", "-lfoo"]) +for k,v in sorted(d.items()): + if v: + print k, v +env.MergeFlags(d) +env.Program('f1.c') +
% scons -Q
+CPPPATH ['/opt/include']
+LIBPATH ['/opt/lib']
+LIBS ['foo']
+cc -o f1.o -c -I/opt/include f1.c
+cc -o f1 f1.o -L/opt/lib -lfoo
+
+
+ ParseFlags
is regularly updated for new options;
+ consult the man page for details about those currently recognized.
+
+
+
+ Configuring the right options to build programs to work with
+ libraries--especially shared libraries--that are available
+ on POSIX systems can be very complicated.
+ To help this situation,
+ various utilies with names that end in config
+ return the command-line options for the GNU Compiler Collection (GCC)
+ that are needed to use these libraries;
+ for example, the command-line options
+ to use a library named lib
+ would be found by calling a utility named lib-config
.
+
+
+
+ A more recent convention is that these options
+ are available from the generic pkg-config
program,
+ which has common framework, error handling, and the like,
+ so that all the package creator has to do is provide the set of strings
+ for his particular package.
+
+
+
+ SCons construction environments have a ParseConfig
method
+ that executes a *config
utility
+ (either pkg-config
or a
+ more specific utility)
+ and configures the appropriate construction variables
+ in the environment
+ based on the command-line options
+ returned by the specified command.
+
+
+env = Environment() +env['CPPPATH'] = ['/lib/compat'] +env.ParseConfig("pkg-config x11 --cflags --libs") +print env['CPPPATH'] +
+ + SCons will execute the specified command string, + parse the resultant flags, + and add the flags to the appropriate environment variables. + +
+% scons -Q
+['/lib/compat', '/usr/X11/include']
+scons: `.' is up to date.
+
+
+ In the example above, SCons has added the include directory to
+ CPPPATH
.
+ (Depending upon what other flags are emitted by the
+ pkg-config
command,
+ other variables may have been extended as well.)
+
+
+
+ Note that the options are merged with existing options using
+ the MergeFlags
method,
+ so that each option only occurs once in the construction variable:
+
+
+env = Environment() +env.ParseConfig("pkg-config x11 --cflags --libs") +env.ParseConfig("pkg-config x11 --cflags --libs") +print env['CPPPATH'] +
+% scons -Q
+['/usr/X11/include']
+scons: `.' is up to date.
+
+ + A key aspect of creating a usable build configuration + is providing good output from the build + so its users can readily understand + what the build is doing + and get information about how to control the build. + SCons provides several ways of + controlling output from the build configuration + to help make the build + more useful and understandable. + +
+
+ It's often very useful to be able to give
+ users some help that describes the
+ specific targets, build options, etc.,
+ that can be used for your build.
+ SCons provides the Help
function
+ to allow you to specify this help text:
+
+
+Help(""" +Type: 'scons program' to build the production program, + 'scons debug' to build the debug version. +""") +
+ + Optionally, one can specify the append flag: + +
+Help(""" +Type: 'scons program' to build the production program, + 'scons debug' to build the debug version. +""", append=True) +
+ + (Note the above use of the Python triple-quote syntax, + which comes in very handy for + specifying multi-line strings like help text.) + +
+
+ When the SConstruct
or SConscript
files
+ contain such a call to the Help
function,
+ the specified help text will be displayed in response to
+ the SCons -h
option:
+
+
% scons -h
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+
+Type: 'scons program' to build the production program,
+ 'scons debug' to build the debug version.
+
+Use scons -H for help about command-line options.
+
+
+ The SConscript
files may contain
+ multiple calls to the Help
function,
+ in which case the specified text(s)
+ will be concatenated when displayed.
+ This allows you to split up the
+ help text across multiple SConscript
files.
+ In this situation, the order in
+ which the SConscript
files are called
+ will determine the order in which the Help
functions are called,
+ which will determine the order in which
+ the various bits of text will get concatenated.
+
+
+
+ When used with AddOption
Help("text", append=False) will clobber any help output associated with AddOption().
+ To preserve the help output from AddOption(), set append=True.
+
+
+
+ Another use would be to make the help text conditional
+ on some variable.
+ For example, suppose you only want to display
+ a line about building a Windows-only
+ version of a program when actually
+ run on Windows.
+ The following SConstruct
file:
+
+
+env = Environment() + +Help("\nType: 'scons program' to build the production program.\n") + +if env['PLATFORM'] == 'win32': + Help("\nType: 'scons windebug' to build the Windows debug version.\n") +
+ + Will display the complete help text on Windows: + +
C:\>scons -h
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+
+Type: 'scons program' to build the production program.
+
+Type: 'scons windebug' to build the Windows debug version.
+
+Use scons -H for help about command-line options.
+
+ + But only show the relevant option on a Linux or UNIX system: + +
% scons -h
+scons: Reading SConscript files ...
+scons: done reading SConscript files.
+
+Type: 'scons program' to build the production program.
+
+Use scons -H for help about command-line options.
+
+
+ If there is no Help
text in the SConstruct
or
+ SConscript
files,
+ SCons will revert to displaying its
+ standard list that describes the SCons command-line
+ options.
+ This list is also always displayed whenever
+ the -H
option is used.
+
+
+
+ Sometimes the commands executed
+ to compile object files or link programs
+ (or build other targets)
+ can get very long,
+ long enough to make it difficult for users
+ to distinguish error messages or
+ other important build output
+ from the commands themselves.
+ All of the default $*COM
variables
+ that specify the command lines
+ used to build various types of target files
+ have a corresponding $*COMSTR
variable
+ that can be set to an alternative
+ string that will be displayed
+ when the target is built.
+
+
+
+ For example, suppose you want to
+ have SCons display a
+ "Compiling"
+ message whenever it's compiling an object file,
+ and a
+ "Linking"
+ when it's linking an executable.
+ You could write a SConstruct
file
+ that looks like:
+
+
+env = Environment(CCCOMSTR = "Compiling $TARGET", + LINKCOMSTR = "Linking $TARGET") +env.Program('foo.c') +
+ + Which would then yield the output: + +
+% scons -Q
+Compiling foo.o
+Linking foo
+
+
+ SCons performs complete variable substitution
+ on $*COMSTR
variables,
+ so they have access to all of the
+ standard variables like $TARGET
$SOURCES
, etc.,
+ as well as any construction variables
+ that happen to be configured in
+ the construction environment
+ used to build a specific target.
+
+
+ + Of course, sometimes it's still important to + be able to see the exact command + that SCons will execute to build a target. + For example, you may simply need to verify + that SCons is configured to supply + the right options to the compiler, + or a developer may want to + cut-and-paste a compile command + to add a few options + for a custom test. + +
+
+ One common way to give users
+ control over whether or not
+ SCons should print the actual command line
+ or a short, configured summary
+ is to add support for a
+ VERBOSE
+ command-line variable to your SConstruct
file.
+ A simple configuration for this might look like:
+
+
+env = Environment() +if ARGUMENTS.get('VERBOSE') != "1': + env['CCCOMSTR'] = "Compiling $TARGET" + env['LINKCOMSTR'] = "Linking $TARGET" +env.Program('foo.c') +
+
+
+ By only setting the appropriate
+ $*COMSTR
variables
+ if the user specifies
+ VERBOSE=1
+ on the command line,
+ the user has control
+ over how SCons
+ displays these particular command lines:
+
+
+%scons -Q
+Compiling foo.o +Linking foo +%scons -Q -c
+Removed foo.o +Removed foo +%scons -Q VERBOSE=1
+cc -o foo.o -c foo.c +cc -o foo foo.o +
+ + Another aspect of providing good build output + is to give the user feedback + about what SCons is doing + even when nothing is being built at the moment. + This can be especially true for large builds + when most of the targets are already up-to-date. + Because SCons can take a long time + making absolutely sure that every + target is, in fact, up-to-date + with respect to a lot of dependency files, + it can be easy for users to mistakenly + conclude that SCons is hung + or that there is some other problem with the build. + +
+
+ One way to deal with this perception
+ is to configure SCons to print something to
+ let the user know what it's "thinking about."
+ The Progress
function
+ allows you to specify a string
+ that will be printed for every file
+ that SCons is "considering"
+ while it is traversing the dependency graph
+ to decide what targets are or are not up-to-date.
+
+
+Progress('Evaluating $TARGET\n') +Program('f1.c') +Program('f2.c') +
+
+ Note that the Progress
function does not
+ arrange for a newline to be printed automatically
+ at the end of the string (as does the Python
+ print
statement),
+ and we must specify the
+ \n
+ that we want printed at the end of the configured string.
+ This configuration, then,
+ will have SCons
+ print that it is Evaluating
+ each file that it encounters
+ in turn as it traverses the dependency graph:
+
+
% scons -Q
+Evaluating SConstruct
+Evaluating f1.c
+Evaluating f1.o
+cc -o f1.o -c f1.c
+Evaluating f1
+cc -o f1 f1.o
+Evaluating f2.c
+Evaluating f2.o
+cc -o f2.o -c f2.c
+Evaluating f2
+cc -o f2 f2.o
+Evaluating .
+
+
+ Of course, normally you don't want to add
+ all of these additional lines to your build output,
+ as that can make it difficult for the user
+ to find errors or other important messages.
+ A more useful way to display
+ this progress might be
+ to have the file names printed
+ directly to the user's screen,
+ not to the same standard output
+ stream where build output is printed,
+ and to use a carriage return character
+ (\r
)
+ so that each file name gets re-printed on the same line.
+ Such a configuration would look like:
+
+
+Progress('$TARGET\r', + file=open('/dev/tty', 'w'), + overwrite=True) +Program('f1.c') +Program('f2.c') +
+
+ Note that we also specified the
+ overwrite=True
argument
+ to the Progress
function,
+ which causes SCons to
+ "wipe out" the previous string with space characters
+ before printing the next Progress
string.
+ Without the
+ overwrite=True
argument,
+ a shorter file name would not overwrite
+ all of the charactes in a longer file name that
+ precedes it,
+ making it difficult to tell what the
+ actual file name is on the output.
+ Also note that we opened up the
+ /dev/tty
file
+ for direct access (on POSIX) to
+ the user's screen.
+ On Windows, the equivalent would be to open
+ the con:
file name.
+
+
+
+ Also, it's important to know that although you can use
+ $TARGET
to substitute the name of
+ the node in the string,
+ the Progress
function does not
+ perform general variable substitution
+ (because there's not necessarily a construction
+ environment involved in evaluating a node
+ like a source file, for example).
+
+
+
+ You can also specify a list of strings
+ to the Progress
function,
+ in which case SCons will
+ display each string in turn.
+ This can be used to implement a "spinner"
+ by having SCons cycle through a
+ sequence of strings:
+
+
+Progress(['-\r', '\\\r', '|\r', '/\r'], interval=5) +Program('f1.c') +Program('f2.c') +
+
+ Note that here we have also used the
+ interval=
+ keyword argument to have SCons
+ only print a new "spinner" string
+ once every five evaluated nodes.
+ Using an interval=
count,
+ even with strings that use $TARGET
like
+ our examples above,
+ can be a good way to lessen the
+ work that SCons expends printing Progress
strings,
+ while still giving the user feedback
+ that indicates SCons is still
+ working on evaluating the build.
+
+
+
+ Lastly, you can have direct control
+ over how to print each evaluated node
+ by passing a Python function
+ (or other Python callable)
+ to the Progress
function.
+ Your function will be called
+ for each evaluated node,
+ allowing you to
+ implement more sophisticated logic
+ like adding a counter:
+
+
+screen = open('/dev/tty', 'w') +count = 0 +def progress_function(node) + count += 1 + screen.write('Node %4d: %s\r' % (count, node)) + +Progress(progress_function) +
+
+ Of course, if you choose,
+ you could completely ignore the
+ node
argument to the function,
+ and just print a count,
+ or anything else you wish.
+
+
+ + (Note that there's an obvious follow-on question here: + how would you find the total number of nodes + that will be + evaluated so you can tell the user how + close the build is to finishing? + Unfortunately, in the general case, + there isn't a good way to do that, + short of having SCons evaluate its + dependency graph twice, + first to count the total and + the second time to actually build the targets. + This would be necessary because + you can't know in advance which + target(s) the user actually requested + to be built. + The entire build may consist of thousands of Nodes, + for example, + but maybe the user specifically requested + that only a single object file be built.) + +
+ + SCons, like most build tools, returns zero status to + the shell on success and nonzero status on failure. + Sometimes it's useful to give more information about + the build status at the end of the run, for instance + to print an informative message, send an email, or + page the poor slob who broke the build. + +
+
+ SCons provides a GetBuildFailures
method that
+ you can use in a python atexit
function
+ to get a list of objects describing the actions that failed
+ while attempting to build targets. There can be more
+ than one if you're using -j
. Here's a
+ simple example:
+
+
+import atexit + +def print_build_failures(): + from SCons.Script import GetBuildFailures + for bf in GetBuildFailures(): + print("%s failed: %s" % (bf.node, bf.errstr)) +atexit.register(print_build_failures) +
+
+ The atexit.register
call
+ registers print_build_failures
+ as an atexit
callback, to be called
+ before SCons exits. When that function is called,
+ it calls GetBuildFailures
to fetch the list of failed objects.
+ See the man page
+ for the detailed contents of the returned objects;
+ some of the more useful attributes are
+ .node
,
+ .errstr
,
+ .filename
, and
+ .command
.
+ The filename
is not necessarily
+ the same file as the node
; the
+ node
is the target that was
+ being built when the error occurred, while the
+ filename
is the file or dir that
+ actually caused the error.
+ Note: only call GetBuildFailures
at the end of the
+ build; calling it at any other time is undefined.
+
+
+
+ Here is a more complete example showing how to
+ turn each element of GetBuildFailures
into a string:
+
+
+# Make the build fail if we pass fail=1 on the command line +if ARGUMENTS.get('fail', 0): + Command('target', 'source', ['/bin/false']) + +def bf_to_str(bf): + """Convert an element of GetBuildFailures() to a string + in a useful way.""" + import SCons.Errors + if bf is None: # unknown targets product None in list + return '(unknown tgt)' + elif isinstance(bf, SCons.Errors.StopError): + return str(bf) + elif bf.node: + return str(bf.node) + ': ' + bf.errstr + elif bf.filename: + return bf.filename + ': ' + bf.errstr + return 'unknown failure: ' + bf.errstr +import atexit + +def build_status(): + """Convert the build status to a 2-tuple, (status, msg).""" + from SCons.Script import GetBuildFailures + bf = GetBuildFailures() + if bf: + # bf is normally a list of build failures; if an element is None, + # it's because of a target that scons doesn't know anything about. + status = 'failed' + failures_message = "\n".join(["Failed building %s" % bf_to_str(x) + for x in bf if x is not None]) + else: + # if bf is None, the build completed successfully. + status = 'ok' + failures_message = '' + return (status, failures_message) + +def display_build_status(): + """Display the build status. Called by atexit. + Here you could do all kinds of complicated things.""" + status, failures_message = build_status() + if status == 'failed': + print("FAILED!!!!") # could display alert, ring bell, etc. + elif status == 'ok': + print("Build succeeded.") + print(failures_message) + +atexit.register(display_build_status) +
+ + When this runs, you'll see the appropriate output: + +
%scons -Q
+scons: `.' is up to date. +Build succeeded. +%scons -Q fail=1
+scons: *** [target] Source `source' not found, needed by target `target'. +FAILED!!!! +Failed building target: Source `source' not found, needed by target `target'. +
+
+ SCons provides a number of ways
+ for the writer of the SConscript
files
+ to give the users who will run SCons
+ a great deal of control over the build execution.
+ The arguments that the user can specify on
+ the command line are broken down into three types:
+
+
+
+ Command-line options always begin with
+ one or two -
(hyphen) characters.
+ SCons provides ways for you to examine
+ and set options values from within your SConscript
files,
+ as well as the ability to define your own
+ custom options.
+ See Section 10.1, “Command-Line Options”, below.
+
+
+
+ Any command-line argument containing an =
+ (equal sign) is considered a variable setting with the form
+ variable
=value
.
+ SCons provides direct access to
+ all of the command-line variable settings,
+ the ability to apply command-line variable settings
+ to construction environments,
+ and functions for configuring
+ specific types of variables
+ (Boolean values, path names, etc.)
+ with automatic validation of the user's specified values.
+ See Section 10.2, “Command-Line variable
=value
Build Variables”, below.
+
+
+
+ Any command-line argument that is not an option
+ or a variable setting
+ (does not begin with a hyphen
+ and does not contain an equal sign)
+ is considered a target that the user
+ (presumably) wants SCons to build.
+ A list of Node objects representing
+ the target or targets to build.
+ SCons provides access to the list of specified targets,
+ as well as ways to set the default list of targets
+ from within the SConscript
files.
+ See Section 10.3, “Command-Line Targets”, below.
+
+
+
+ SCons has many command-line options
+ that control its behavior.
+ A SCons command-line option
+ always begins with one or two -
(hyphen)
+ characters.
+
+
+
+ Users may find themselves supplying
+ the same command-line options every time
+ they run SCons.
+ For example, you might find it saves time
+ to specify a value of -j 2
+ to have SCons run up to two build commands in parallel.
+ To avoid having to type -j 2
by hand
+ every time,
+ you can set the external environment variable
+ SCONSFLAGS
to a string containing
+ command-line options that you want SCons to use.
+
+
+
+ If, for example,
+ you're using a POSIX shell that's
+ compatible with the Bourne shell,
+ and you always want SCons to use the
+ -Q
option,
+ you can set the SCONSFLAGS
+ environment as follows:
+
+
%scons
+scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Building targets ... + ... [build output] ... +scons: done building targets. +%export SCONSFLAGS="-Q"
+%scons
+ ... [build output] ... +
+
+ Users of csh-style shells on POSIX systems
+ can set the SCONSFLAGS
environment as follows:
+
+
+$ setenv SCONSFLAGS "-Q"
+
+
+ Windows users may typically want to set the
+ SCONSFLAGS
in the appropriate tab of the
+ System Properties
window.
+
+
+
+ SCons provides the GetOption
function
+ to get the values set by the various command-line options.
+ One common use of this is to check whether or not
+ the -h
or --help
option
+ has been specified.
+ Normally, SCons does not print its help text
+ until after it has read all of the SConscript
files,
+ because it's possible that help text has been added
+ by some subsidiary SConscript
file deep in the
+ source tree hierarchy.
+ Of course, reading all of the SConscript
files
+ takes extra time.
+
+
+
+ If you know that your configuration does not define
+ any additional help text in subsidiary SConscript
files,
+ you can speed up the command-line help available to users
+ by using the GetOption
function to load the
+ subsidiary SConscript
files only if the
+ the user has not specified
+ the -h
or --help
option,
+ like so:
+
+
+if not GetOption('help'): + SConscript('src/SConscript', export='env') +
+
+ In general, the string that you pass to the
+ GetOption
function to fetch the value of a command-line
+ option setting is the same as the "most common" long option name
+ (beginning with two hyphen characters),
+ although there are some exceptions.
+ The list of SCons command-line options
+ and the GetOption
strings for fetching them,
+ are available in the
+ Section 10.1.4, “Strings for Getting or Setting Values of SCons Command-Line Options” section,
+ below.
+
+
+
+ You can also set the values of SCons
+ command-line options from within the SConscript
files
+ by using the SetOption
function.
+ The strings that you use to set the values of SCons
+ command-line options are available in the
+ Section 10.1.4, “Strings for Getting or Setting Values of SCons Command-Line Options” section,
+ below.
+
+
+
+ One use of the SetOption
function is to
+ specify a value for the -j
+ or --jobs
option,
+ so that users get the improved performance
+ of a parallel build without having to specify the option by hand.
+ A complicating factor is that a good value
+ for the -j
option is
+ somewhat system-dependent.
+ One rough guideline is that the more processors
+ your system has,
+ the higher you want to set the
+ -j
value,
+ in order to take advantage of the number of CPUs.
+
+
+
+ For example, suppose the administrators
+ of your development systems
+ have standardized on setting a
+ NUM_CPU
environment variable
+ to the number of processors on each system.
+ A little bit of Python code
+ to access the environment variable
+ and the SetOption
function
+ provide the right level of flexibility:
+
+
+import os +num_cpu = int(os.environ.get('NUM_CPU', 2)) +SetOption('num_jobs', num_cpu) +print("running with -j %s"%GetOption('num_jobs')) +
+
+ The above snippet of code
+ sets the value of the --jobs
option
+ to the value specified in the
+ $NUM_CPU
environment variable.
+ (This is one of the exception cases
+ where the string is spelled differently from
+ the from command-line option.
+ The string for fetching or setting the --jobs
+ value is num_jobs
+ for historical reasons.)
+ The code in this example prints the num_jobs
+ value for illustrative purposes.
+ It uses a default value of 2
+ to provide some minimal parallelism even on
+ single-processor systems:
+
+
% scons -Q
+running with -j 2
+scons: `.' is up to date.
+
+
+ But if the $NUM_CPU
+ environment variable is set,
+ then we use that for the default number of jobs:
+
+
%export NUM_CPU="4"
+%scons -Q
+running with -j 4 +scons: `.' is up to date. +
+
+ But any explicit
+ -j
or --jobs
+ value the user specifies an the command line is used first,
+ regardless of whether or not
+ the $NUM_CPU
environment
+ variable is set:
+
+
%scons -Q -j 7
+running with -j 7 +scons: `.' is up to date. +%export NUM_CPU="4"
+%scons -Q -j 3
+running with -j 3 +scons: `.' is up to date. +
+
+ The strings that you can pass to the GetOption
+ and SetOption
functions usually correspond to the
+ first long-form option name
+ (beginning with two hyphen characters: --
),
+ after replacing any remaining hyphen characters
+ with underscores.
+
+
+ + The full list of strings and the variables they + correspond to is as follows: + +
String for GetOption and SetOption | Command-Line Option(s) |
---|---|
cache_debug | --cache-debug |
cache_disable | --cache-disable |
cache_force | --cache-force |
cache_show | --cache-show |
clean | -c ,
+ --clean ,
+ --remove |
config | --config |
directory | -C ,
+ --directory |
diskcheck | --diskcheck |
duplicate | --duplicate |
file | -f ,
+ --file ,
+ --makefile ,
+ --sconstruct |
help | -h ,
+ --help |
ignore_errors | --ignore-errors |
implicit_cache | --implicit-cache |
implicit_deps_changed | --implicit-deps-changed |
implicit_deps_unchanged | --implicit-deps-unchanged |
interactive | --interact ,
+ --interactive |
keep_going | -k ,
+ --keep-going |
max_drift | --max-drift |
no_exec | -n ,
+ --no-exec ,
+ --just-print ,
+ --dry-run ,
+ --recon |
no_site_dir | --no-site-dir |
num_jobs | -j ,
+ --jobs |
profile_file | --profile |
question | -q ,
+ --question |
random | --random |
repository | -Y ,
+ --repository ,
+ --srcdir |
silent | -s ,
+ --silent ,
+ --quiet |
site_dir | --site-dir |
stack_size | --stack-size |
taskmastertrace_file | --taskmastertrace |
warn | --warn --warning |
+
+ SCons also allows you to define your own
+ command-line options with the AddOption
function.
+ The AddOption
function takes the same arguments
+ as the optparse.add_option
function
+ from the standard Python library.
+ [3]
+ Once you have added a custom command-line option
+ with the AddOption
function,
+ the value of the option (if any) is immediately available
+ using the standard GetOption
function.
+ (The value can also be set using SetOption
,
+ although that's not very useful in practice
+ because a default value can be specified in
+ directly in the AddOption
call.)
+
+
+
+ One useful example of using this functionality
+ is to provide a --prefix
for users:
+
+
+AddOption('--prefix', + dest='prefix', + type='string', + nargs=1, + action='store', + metavar='DIR', + help='installation prefix') + +env = Environment(PREFIX = GetOption('prefix')) + +installed_foo = env.Install('$PREFIX/usr/bin', 'foo.in') +Default(installed_foo) +
+
+ The above code uses the GetOption
function
+ to set the $PREFIX
+ construction variable to any
+ value that the user specifies with a command-line
+ option of --prefix
.
+ Because $PREFIX
+ will expand to a null string if it's not initialized,
+ running SCons without the
+ option of --prefix
+ will install the file in the
+ /usr/bin/
directory:
+
+
% scons -Q -n
+Install file: "foo.in" as "/usr/bin/foo.in"
+
+
+ But specifying --prefix=/tmp/install
+ on the command line causes the file to be installed in the
+ /tmp/install/usr/bin/
directory:
+
+
% scons -Q -n --prefix=/tmp/install
+Install file: "foo.in" as "/tmp/install/usr/bin/foo.in"
+
+
+ You may want to control various aspects
+ of your build by allowing the user
+ to specify variable
=value
+ values on the command line.
+ For example, suppose you
+ want users to be able to
+ build a debug version of a program
+ by running SCons as follows:
+
+
+% scons -Q debug=1
+
+
+ SCons provides an ARGUMENTS
dictionary
+ that stores all of the
+ variable
=value
+ assignments from the command line.
+ This allows you to modify
+ aspects of your build in response
+ to specifications on the command line.
+ (Note that unless you want to require
+ that users always
+ specify a variable,
+ you probably want to use
+ the Python
+ ARGUMENTS.get()
function,
+ which allows you to specify a default value
+ to be used if there is no specification
+ on the command line.)
+
+
+
+ The following code sets the $CCFLAGS
construction
+ variable in response to the debug
+ flag being set in the ARGUMENTS
dictionary:
+
+
+env = Environment() +debug = ARGUMENTS.get('debug', 0) +if int(debug): + env.Append(CCFLAGS = '-g') +env.Program('prog.c') +
+
+ This results in the -g
+ compiler option being used when
+ debug=1
+ is used on the command line:
+
+
%scons -Q debug=0
+cc -o prog.o -c prog.c +cc -o prog prog.o +%scons -Q debug=0
+scons: `.' is up to date. +%scons -Q debug=1
+cc -o prog.o -c -g prog.c +cc -o prog prog.o +%scons -Q debug=1
+scons: `.' is up to date. +
+
+ Notice that SCons keeps track of
+ the last values used to build the object files,
+ and as a result correctly rebuilds
+ the object and executable files
+ only when the value of the debug
+ argument has changed.
+
+
+
+ The ARGUMENTS
dictionary has two minor drawbacks.
+ First, because it is a dictionary,
+ it can only store one value for each specified keyword,
+ and thus only "remembers" the last setting
+ for each keyword on the command line.
+ This makes the ARGUMENTS
dictionary
+ inappropriate if users should be able to
+ specify multiple values
+ on the command line for a given keyword.
+ Second, it does not preserve
+ the order in which the variable settings
+ were specified,
+ which is a problem if
+ you want the configuration to
+ behave differently in response
+ to the order in which the build
+ variable settings were specified on the command line.
+
+
+
+ To accomodate these requirements,
+ SCons provides an ARGLIST
variable
+ that gives you direct access to
+ variable
=value
+ settings on the command line,
+ in the exact order they were specified,
+ and without removing any duplicate settings.
+ Each element in the ARGLIST
variable
+ is itself a two-element list
+ containing the keyword and the value
+ of the setting,
+ and you must loop through,
+ or otherwise select from,
+ the elements of ARGLIST
to
+ process the specific settings you want
+ in whatever way is appropriate for your configuration.
+ For example,
+ the following code to let the user
+ add to the CPPDEFINES
construction variable
+ by specifying multiple
+ define=
+ settings on the command line:
+
+
+cppdefines = [] +for key, value in ARGLIST: + if key == 'define': + cppdefines.append(value) +env = Environment(CPPDEFINES = cppdefines) +env.Object('prog.c') +
+ + Yields the following output: + +
%scons -Q define=FOO
+cc -o prog.o -c -DFOO prog.c +%scons -Q define=FOO define=BAR
+cc -o prog.o -c -DFOO -DBAR prog.c +
+
+ Note that the ARGLIST
and ARGUMENTS
+ variables do not interfere with each other,
+ but merely provide slightly different views
+ into how the user specified
+ variable
=value
+ settings on the command line.
+ You can use both variables in the same
+ SCons configuration.
+ In general, the ARGUMENTS
dictionary
+ is more convenient to use,
+ (since you can just fetch variable
+ settings through a dictionary access),
+ and the ARGLIST
list
+ is more flexible
+ (since you can examine the
+ specific order in which
+ the user's command-line variabe settings).
+
+
+
+ Being able to use a command-line build variable like
+ debug=1
is handy,
+ but it can be a chore to write specific Python code
+ to recognize each such variable,
+ check for errors and provide appropriate messages,
+ and apply the values to a construction variable.
+ To help with this,
+ SCons supports a class to
+ define such build variables easily,
+ and a mechanism to apply the
+ build variables to a construction environment.
+ This allows you to control how the build variables affect
+ construction environments.
+
+
+
+ For example, suppose that you want users to set
+ a RELEASE
construction variable on the
+ command line whenever the time comes to build
+ a program for release,
+ and that the value of this variable
+ should be added to the command line
+ with the appropriate -D
option
+ (or other command line option)
+ to pass the value to the C compiler.
+ Here's how you might do that by setting
+ the appropriate value in a dictionary for the
+ $CPPDEFINES
construction variable:
+
+
+vars = Variables(None, ARGUMENTS) +vars.Add('RELEASE', 'Set to 1 to build for release', 0) +env = Environment(variables = vars, + CPPDEFINES={'RELEASE_BUILD' : '${RELEASE}'}) +env.Program(['foo.c', 'bar.c']) +
+
+ This SConstruct
file first creates a Variables
object
+ which uses the values from the command-line options dictionary ARGUMENTS
+ (the vars = Variables(None, ARGUMENTS)
call).
+ It then uses the object's Add
+ method to indicate that the RELEASE
+ variable can be set on the command line,
+ and that its default value will be 0
+ (the third argument to the Add
method).
+ The second argument is a line of help text;
+ we'll learn how to use it in the next section.
+
+
+
+ We then pass the created Variables
+ object as a variables
keyword argument
+ to the Environment
call
+ used to create the construction environment.
+ This then allows a user to set the
+ RELEASE
build variable on the command line
+ and have the variable show up in
+ the command line used to build each object from
+ a C source file:
+
+
% scons -Q RELEASE=1
+cc -o bar.o -c -DRELEASE_BUILD=1 bar.c
+cc -o foo.o -c -DRELEASE_BUILD=1 foo.c
+cc -o foo foo.o bar.o
+
+
+ NOTE: Before SCons release 0.98.1, these build variables
+ were known as "command-line build options."
+ The class was actually named the Options
class,
+ and in the sections below,
+ the various functions were named
+ BoolOption
, EnumOption
, ListOption
,
+ PathOption
, PackageOption
and AddOptions
.
+ These older names still work,
+ and you may encounter them in older
+ SConscript
files,
+ but they have been officially deprecated
+ as of SCons version 2.0.
+
+
+
+ To make command-line build variables most useful,
+ you ideally want to provide
+ some help text that will describe
+ the available variables
+ when the user runs scons -h
.
+ You could write this text by hand,
+ but SCons provides an easier way.
+ Variables
objects support a
+ GenerateHelpText
method
+ that will, as its name suggests,
+ generate text that describes
+ the various variables that
+ have been added to it.
+ You then pass the output from this method to
+ the Help
function:
+
+
+vars = Variables(None, ARGUMENTS) +vars.Add('RELEASE', 'Set to 1 to build for release', 0) +env = Environment(variables = vars) +Help(vars.GenerateHelpText(env)) +
+
+ SCons will now display some useful text
+ when the -h
option is used:
+
+
% scons -Q -h
+
+RELEASE: Set to 1 to build for release
+ default: 0
+ actual: 0
+
+Use scons -H for help about command-line options.
+
+ + Notice that the help output shows the default value, + and the current actual value of the build variable. + +
+
+ Giving the user a way to specify the
+ value of a build variable on the command line
+ is useful,
+ but can still be tedious
+ if users must specify the variable
+ every time they run SCons.
+ We can let users provide customized build variable settings
+ in a local file by providing a
+ file name when we create the
+ Variables
object:
+
+
+vars = Variables('custom.py') +vars.Add('RELEASE', 'Set to 1 to build for release', 0) +env = Environment(variables = vars, + CPPDEFINES={'RELEASE_BUILD' : '${RELEASE}'}) +env.Program(['foo.c', 'bar.c']) +Help(vars.GenerateHelpText(env)) +
+
+ This then allows the user to control the RELEASE
+ variable by setting it in the custom.py
file:
+
+
+RELEASE = 1 + +
+ + Note that this file is actually executed + like a Python script. + Now when we run SCons: + +
% scons -Q
+cc -o bar.o -c -DRELEASE_BUILD=1 bar.c
+cc -o foo.o -c -DRELEASE_BUILD=1 foo.c
+cc -o foo foo.o bar.o
+
+
+ And if we change the contents of custom.py
to:
+
+
+RELEASE = 0 +
+ + The object files are rebuilt appropriately + with the new variable: + +
% scons -Q
+cc -o bar.o -c -DRELEASE_BUILD=0 bar.c
+cc -o foo.o -c -DRELEASE_BUILD=0 foo.c
+cc -o foo foo.o bar.o
+
+ + Finally, you can combine both methods with: + +
+vars = Variables('custom.py', ARGUMENTS) +
+
+ where values in the option file custom.py
get overwritten
+ by the ones specified on the command line.
+
+
+ + SCons provides a number of functions + that provide ready-made behaviors + for various types of command-line build variables. + +
+
+ It's often handy to be able to specify a
+ variable that controls a simple Boolean variable
+ with a true
or false
value.
+ It would be even more handy to accomodate
+ users who have different preferences for how to represent
+ true
or false
values.
+ The BoolVariable
function
+ makes it easy to accomodate these
+ common representations of
+ true
or false
.
+
+
+
+ The BoolVariable
function takes three arguments:
+ the name of the build variable,
+ the default value of the build variable,
+ and the help string for the variable.
+ It then returns appropriate information for
+ passing to the Add
method of a Variables
object, like so:
+
+
+vars = Variables('custom.py') +vars.Add(BoolVariable('RELEASE', 'Set to build for release', 0)) +env = Environment(variables = vars, + CPPDEFINES={'RELEASE_BUILD' : '${RELEASE}'}) +env.Program('foo.c') +
+
+ With this build variable,
+ the RELEASE
variable can now be enabled by
+ setting it to the value yes
+ or t
:
+
+
% scons -Q RELEASE=yes foo.o
+cc -o foo.o -c -DRELEASE_BUILD=True foo.c
+
% scons -Q RELEASE=t foo.o
+cc -o foo.o -c -DRELEASE_BUILD=True foo.c
+
+
+ Other values that equate to true
include
+ y
,
+ 1
,
+ on
+ and
+ all
.
+
+
+
+ Conversely, RELEASE
may now be given a false
+ value by setting it to
+ no
+ or
+ f
:
+
+
% scons -Q RELEASE=no foo.o
+cc -o foo.o -c -DRELEASE_BUILD=False foo.c
+
% scons -Q RELEASE=f foo.o
+cc -o foo.o -c -DRELEASE_BUILD=False foo.c
+
+
+ Other values that equate to false
include
+ n
,
+ 0
,
+ off
+ and
+ none
.
+
+
+ + Lastly, if a user tries to specify + any other value, + SCons supplies an appropriate error message: + +
% scons -Q RELEASE=bad_value foo.o
+
+scons: *** Error converting option: RELEASE
+Invalid value for boolean option: bad_value
+File "/home/my/project/SConstruct", line 4, in <module>
+
+
+ Suppose that we want a user to be able to
+ set a COLOR
variable
+ that selects a background color to be
+ displayed by an application,
+ but that we want to restrict the
+ choices to a specific set of allowed colors.
+ This can be set up quite easily
+ using the EnumVariable
,
+ which takes a list of allowed_values
+ in addition to the variable name,
+ default value,
+ and help text arguments:
+
+
+vars = Variables('custom.py') +vars.Add(EnumVariable('COLOR', 'Set background color', 'red', + allowed_values=('red', 'green', 'blue'))) +env = Environment(variables = vars, + CPPDEFINES={'COLOR' : '"${COLOR}"'}) +env.Program('foo.c') +
+
+ The user can now explicity set the COLOR
build variable
+ to any of the specified allowed values:
+
+
%scons -Q COLOR=red foo.o
+cc -o foo.o -c -DCOLOR="red" foo.c +%scons -Q COLOR=blue foo.o
+cc -o foo.o -c -DCOLOR="blue" foo.c +%scons -Q COLOR=green foo.o
+cc -o foo.o -c -DCOLOR="green" foo.c +
+
+ But, almost more importantly,
+ an attempt to set COLOR
+ to a value that's not in the list
+ generates an error message:
+
+
% scons -Q COLOR=magenta foo.o
+
+scons: *** Invalid value for option COLOR: magenta. Valid values are: ('red', 'green', 'blue')
+File "/home/my/project/SConstruct", line 5, in <module>
+
+
+ The EnumVariable
function also supports a way
+ to map alternate names to allowed values.
+ Suppose, for example,
+ that we want to allow the user
+ to use the word navy
as a synonym for
+ blue
.
+ We do this by adding a map
dictionary
+ that will map its key values
+ to the desired legal value:
+
+
+vars = Variables('custom.py') +vars.Add(EnumVariable('COLOR', 'Set background color', 'red', + allowed_values=('red', 'green', 'blue'), + map={'navy':'blue'})) +env = Environment(variables = vars, + CPPDEFINES={'COLOR' : '"${COLOR}"'}) +env.Program('foo.c') +
+
+ As desired, the user can then use
+ navy
on the command line,
+ and SCons will translate it into blue
+ when it comes time to use the COLOR
+ variable to build a target:
+
+
% scons -Q COLOR=navy foo.o
+cc -o foo.o -c -DCOLOR="blue" foo.c
+
+
+ By default, when using the EnumVariable
function,
+ arguments that differ
+ from the legal values
+ only in case
+ are treated as illegal values:
+
+
%scons -Q COLOR=Red foo.o
+ +scons: *** Invalid value for option COLOR: Red. Valid values are: ('red', 'green', 'blue') +File "/home/my/project/SConstruct", line 5, in <module> +%scons -Q COLOR=BLUE foo.o
+ +scons: *** Invalid value for option COLOR: BLUE. Valid values are: ('red', 'green', 'blue') +File "/home/my/project/SConstruct", line 5, in <module> +%scons -Q COLOR=nAvY foo.o
+ +scons: *** Invalid value for option COLOR: nAvY. Valid values are: ('red', 'green', 'blue') +File "/home/my/project/SConstruct", line 5, in <module> +
+
+ The EnumVariable
function can take an additional
+ ignorecase
keyword argument that,
+ when set to 1
,
+ tells SCons to allow case differences
+ when the values are specified:
+
+
+vars = Variables('custom.py') +vars.Add(EnumVariable('COLOR', 'Set background color', 'red', + allowed_values=('red', 'green', 'blue'), + map={'navy':'blue'}, + ignorecase=1)) +env = Environment(variables = vars, + CPPDEFINES={'COLOR' : '"${COLOR}"'}) +env.Program('foo.c') +
+ + Which yields the output: + +
%scons -Q COLOR=Red foo.o
+cc -o foo.o -c -DCOLOR="Red" foo.c +%scons -Q COLOR=BLUE foo.o
+cc -o foo.o -c -DCOLOR="BLUE" foo.c +%scons -Q COLOR=nAvY foo.o
+cc -o foo.o -c -DCOLOR="blue" foo.c +%scons -Q COLOR=green foo.o
+cc -o foo.o -c -DCOLOR="green" foo.c +
+
+ Notice that an ignorecase
value of 1
+ preserves the case-spelling that the user supplied.
+ If you want SCons to translate the names
+ into lower-case,
+ regardless of the case used by the user,
+ specify an ignorecase
value of 2
:
+
+
+vars = Variables('custom.py') +vars.Add(EnumVariable('COLOR', 'Set background color', 'red', + allowed_values=('red', 'green', 'blue'), + map={'navy':'blue'}, + ignorecase=2)) +env = Environment(variables = vars, + CPPDEFINES={'COLOR' : '"${COLOR}"'}) +env.Program('foo.c') +
+
+ Now SCons will use values of
+ red
,
+ green
or
+ blue
+ regardless of how the user spells
+ those values on the command line:
+
+
%scons -Q COLOR=Red foo.o
+cc -o foo.o -c -DCOLOR="red" foo.c +%scons -Q COLOR=nAvY foo.o
+cc -o foo.o -c -DCOLOR="blue" foo.c +%scons -Q COLOR=GREEN foo.o
+cc -o foo.o -c -DCOLOR="green" foo.c +
+
+ Another way in which you might want to allow users
+ to control a build variable is to
+ specify a list of one or more legal values.
+ SCons supports this through the ListVariable
function.
+ If, for example, we want a user to be able to set a
+ COLORS
variable to one or more of the legal list of values:
+
+
+vars = Variables('custom.py') +vars.Add(ListVariable('COLORS', 'List of colors', 0, + ['red', 'green', 'blue'])) +env = Environment(variables = vars, + CPPDEFINES={'COLORS' : '"${COLORS}"'}) +env.Program('foo.c') +
+ + A user can now specify a comma-separated list + of legal values, + which will get translated into a space-separated + list for passing to the any build commands: + +
%scons -Q COLORS=red,blue foo.o
+cc -o foo.o -c -DCOLORS="red blue" foo.c +%scons -Q COLORS=blue,green,red foo.o
+cc -o foo.o -c -DCOLORS="blue green red" foo.c +
+
+ In addition, the ListVariable
function
+ allows the user to specify explicit keywords of
+ all
or none
+ to select all of the legal values,
+ or none of them, respectively:
+
+
%scons -Q COLORS=all foo.o
+cc -o foo.o -c -DCOLORS="red green blue" foo.c +%scons -Q COLORS=none foo.o
+cc -o foo.o -c -DCOLORS="" foo.c +
+ + And, of course, an illegal value + still generates an error message: + +
% scons -Q COLORS=magenta foo.o
+
+scons: *** Error converting option: COLORS
+Invalid value(s) for option: magenta
+File "/home/my/project/SConstruct", line 5, in <module>
+
+
+ SCons supports a PathVariable
function
+ to make it easy to create a build variable
+ to control an expected path name.
+ If, for example, you need to
+ define a variable in the preprocessor
+ that controls the location of a
+ configuration file:
+
+
+vars = Variables('custom.py') +vars.Add(PathVariable('CONFIG', + 'Path to configuration file', + '/etc/my_config')) +env = Environment(variables = vars, + CPPDEFINES={'CONFIG_FILE' : '"$CONFIG"'}) +env.Program('foo.c') +
+
+ This then allows the user to
+ override the CONFIG
build variable
+ on the command line as necessary:
+
+
%scons -Q foo.o
+cc -o foo.o -c -DCONFIG_FILE="/etc/my_config" foo.c +%scons -Q CONFIG=/usr/local/etc/other_config foo.o
+scons: `foo.o' is up to date. +
+
+ By default, PathVariable
checks to make sure
+ that the specified path exists and generates an error if it
+ doesn't:
+
+
% scons -Q CONFIG=/does/not/exist foo.o
+
+scons: *** Path for option CONFIG does not exist: /does/not/exist
+File "/home/my/project/SConstruct", line 6, in <module>
+
+
+ PathVariable
provides a number of methods
+ that you can use to change this behavior.
+ If you want to ensure that any specified paths are,
+ in fact, files and not directories,
+ use the PathVariable.PathIsFile
method:
+
+
+vars = Variables('custom.py') +vars.Add(PathVariable('CONFIG', + 'Path to configuration file', + '/etc/my_config', + PathVariable.PathIsFile)) +env = Environment(variables = vars, + CPPDEFINES={'CONFIG_FILE' : '"$CONFIG"'}) +env.Program('foo.c') +
+
+ Conversely, to ensure that any specified paths are
+ directories and not files,
+ use the PathVariable.PathIsDir
method:
+
+
+vars = Variables('custom.py') +vars.Add(PathVariable('DBDIR', + 'Path to database directory', + '/var/my_dbdir', + PathVariable.PathIsDir)) +env = Environment(variables = vars, + CPPDEFINES={'DBDIR' : '"$DBDIR"'}) +env.Program('foo.c') +
+
+ If you want to make sure that any specified paths
+ are directories,
+ and you would like the directory created
+ if it doesn't already exist,
+ use the PathVariable.PathIsDirCreate
method:
+
+
+vars = Variables('custom.py') +vars.Add(PathVariable('DBDIR', + 'Path to database directory', + '/var/my_dbdir', + PathVariable.PathIsDirCreate)) +env = Environment(variables = vars, + CPPDEFINES={'DBDIR' : '"$DBDIR"'}) +env.Program('foo.c') +
+
+ Lastly, if you don't care whether the path exists,
+ is a file, or a directory,
+ use the PathVariable.PathAccept
method
+ to accept any path that the user supplies:
+
+
+vars = Variables('custom.py') +vars.Add(PathVariable('OUTPUT', + 'Path to output file or directory', + None, + PathVariable.PathAccept)) +env = Environment(variables = vars, + CPPDEFINES={'OUTPUT' : '"$OUTPUT"'}) +env.Program('foo.c') +
+
+ Sometimes you want to give users
+ even more control over a path name variable,
+ allowing them to explicitly enable or
+ disable the path name
+ by using yes
or no
keywords,
+ in addition to allow them
+ to supply an explicit path name.
+ SCons supports the PackageVariable
+ function to support this:
+
+
+vars = Variables('custom.py') +vars.Add(PackageVariable('PACKAGE', + 'Location package', + '/opt/location')) +env = Environment(variables = vars, + CPPDEFINES={'PACKAGE' : '"$PACKAGE"'}) +env.Program('foo.c') +
+
+ When the SConscript
file uses the PackageVariable
funciton,
+ user can now still use the default
+ or supply an overriding path name,
+ but can now explicitly set the
+ specified variable to a value
+ that indicates the package should be enabled
+ (in which case the default should be used)
+ or disabled:
+
+
%scons -Q foo.o
+cc -o foo.o -c -DPACKAGE="/opt/location" foo.c +%scons -Q PACKAGE=/usr/local/location foo.o
+cc -o foo.o -c -DPACKAGE="/usr/local/location" foo.c +%scons -Q PACKAGE=yes foo.o
+cc -o foo.o -c -DPACKAGE="True" foo.c +%scons -Q PACKAGE=no foo.o
+cc -o foo.o -c -DPACKAGE="False" foo.c +
+
+ Lastly, SCons provides a way to add
+ multiple build variables to a Variables
object at once.
+ Instead of having to call the Add
method
+ multiple times,
+ you can call the AddVariables
+ method with a list of build variables
+ to be added to the object.
+ Each build variable is specified
+ as either a tuple of arguments,
+ just like you'd pass to the Add
method itself,
+ or as a call to one of the pre-defined
+ functions for pre-packaged command-line build variables.
+ in any order:
+
+
+vars = Variables() +vars.AddVariables( + ('RELEASE', 'Set to 1 to build for release', 0), + ('CONFIG', 'Configuration file', '/etc/my_config'), + BoolVariable('warnings', 'compilation with -Wall and similiar', 1), + EnumVariable('debug', 'debug output and symbols', 'no', + allowed_values=('yes', 'no', 'full'), + map={}, ignorecase=0), # case sensitive + ListVariable('shared', + 'libraries to build as shared libraries', + 'all', + names = list_of_libs), + PackageVariable('x11', + 'use X11 installed here (yes = search some places)', + 'yes'), + PathVariable('qtdir', 'where the root of Qt is installed', qtdir), +) +
+
+
+ Users may, of course,
+ occasionally misspell variable names in their command-line settings.
+ SCons does not generate an error or warning
+ for any unknown variables the users specifies on the command line.
+ (This is in no small part because you may be
+ processing the arguments directly using the ARGUMENTS
dictionary,
+ and therefore SCons can't know in the general case
+ whether a given "misspelled" variable is
+ really unknown and a potential problem,
+ or something that your SConscript
file
+ will handle directly with some Python code.)
+
+
+
+ If, however, you're using a Variables
object to
+ define a specific set of command-line build variables
+ that you expect users to be able to set,
+ you may want to provide an error
+ message or warning of your own
+ if the user supplies a variable setting
+ that is not among
+ the defined list of variable names known to the Variables
object.
+ You can do this by calling the UnknownVariables
+ method of the Variables
object:
+
+
+vars = Variables(None) +vars.Add('RELEASE', 'Set to 1 to build for release', 0) +env = Environment(variables = vars, + CPPDEFINES={'RELEASE_BUILD' : '${RELEASE}'}) +unknown = vars.UnknownVariables() +if unknown: + print("Unknown variables: %s"%unknown.keys()) + Exit(1) +env.Program('foo.c') +
+
+ The UnknownVariables
method returns a dictionary
+ containing the keywords and values
+ of any variables the user specified on the command line
+ that are not
+ among the variables known to the Variables
object
+ (from having been specified using
+ the Variables
object'sAdd
method).
+ In the examble above,
+ we check for whether the dictionary
+ returned by the UnknownVariables
is non-empty,
+ and if so print the Python list
+ containing the names of the unknwown variables
+ and then call the Exit
function
+ to terminate SCons:
+
+
% scons -Q NOT_KNOWN=foo
+Unknown variables: ['NOT_KNOWN']
+
+
+ Of course, you can process the items in the
+ dictionary returned by the UnknownVariables
function
+ in any way appropriate to your build configuration,
+ including just printing a warning message
+ but not exiting,
+ logging an error somewhere,
+ etc.
+
+
+
+ Note that you must delay the call of UnknownVariables
+ until after you have applied the Variables
object
+ to a construction environment
+ with the variables=
+ keyword argument of an Environment
call.
+
+
+
+ SCons supports a COMMAND_LINE_TARGETS
variable
+ that lets you fetch the list of targets that the
+ user specified on the command line.
+ You can use the targets to manipulate the
+ build in any way you wish.
+ As a simple example,
+ suppose that you want to print a reminder
+ to the user whenever a specific program is built.
+ You can do this by checking for the
+ target in the COMMAND_LINE_TARGETS
list:
+
+
+if 'bar' in COMMAND_LINE_TARGETS: + print("Don't forget to copy `bar' to the archive!") +Default(Program('foo.c')) +Program('bar.c') +
+
+ Then, running SCons with the default target
+ works as it always does,
+ but explicity specifying the bar
target
+ on the command line generates the warning message:
+
+
%scons -Q
+cc -o foo.o -c foo.c +cc -o foo foo.o +%scons -Q bar
+Don't forget to copy `bar' to the archive! +cc -o bar.o -c bar.c +cc -o bar bar.o +
+
+ Another practical use for the COMMAND_LINE_TARGETS
variable
+ might be to speed up a build
+ by only reading certain subsidiary SConscript
+ files if a specific target is requested.
+
+
+
+ One of the most basic things you can control
+ is which targets SCons will build by default--that is,
+ when there are no targets specified on the command line.
+ As mentioned previously,
+ SCons will normally build every target
+ in or below the current directory
+ by default--that is, when you don't
+ explicitly specify one or more targets
+ on the command line.
+ Sometimes, however, you may want
+ to specify explicitly that only
+ certain programs, or programs in certain directories,
+ should be built by default.
+ You do this with the Default
function:
+
+
+env = Environment() +hello = env.Program('hello.c') +env.Program('goodbye.c') +Default(hello) +
+
+ This SConstruct
file knows how to build two programs,
+ hello
and goodbye
,
+ but only builds the
+ hello
program by default:
+
+
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q
+scons: `hello' is up to date. +%scons -Q goodbye
+cc -o goodbye.o -c goodbye.c +cc -o goodbye goodbye.o +
+
+ Note that, even when you use the Default
+ function in your SConstruct
file,
+ you can still explicitly specify the current directory
+ (.
) on the command line
+ to tell SCons to build
+ everything in (or below) the current directory:
+
+
% scons -Q .
+cc -o goodbye.o -c goodbye.c
+cc -o goodbye goodbye.o
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+
+
+ You can also call the Default
+ function more than once,
+ in which case each call
+ adds to the list of targets to be built by default:
+
+
+env = Environment() +prog1 = env.Program('prog1.c') +Default(prog1) +prog2 = env.Program('prog2.c') +prog3 = env.Program('prog3.c') +Default(prog3) +
+
+ Or you can specify more than one target
+ in a single call to the Default
function:
+
+
+env = Environment() +prog1 = env.Program('prog1.c') +prog2 = env.Program('prog2.c') +prog3 = env.Program('prog3.c') +Default(prog1, prog3) +
+ + Either of these last two examples + will build only the + prog1 + and + prog3 + programs by default: + +
%scons -Q
+cc -o prog1.o -c prog1.c +cc -o prog1 prog1.o +cc -o prog3.o -c prog3.c +cc -o prog3 prog3.o +%scons -Q .
+cc -o prog2.o -c prog2.c +cc -o prog2 prog2.o +
+
+ You can list a directory as
+ an argument to Default
:
+
+
+env = Environment() +env.Program(['prog1/main.c', 'prog1/foo.c']) +env.Program(['prog2/main.c', 'prog2/bar.c']) +Default('prog1') +
+ + In which case only the target(s) in that + directory will be built by default: + +
%scons -Q
+cc -o prog1/foo.o -c prog1/foo.c +cc -o prog1/main.o -c prog1/main.c +cc -o prog1/main prog1/main.o prog1/foo.o +%scons -Q
+scons: `prog1' is up to date. +%scons -Q .
+cc -o prog2/bar.o -c prog2/bar.c +cc -o prog2/main.o -c prog2/main.c +cc -o prog2/main prog2/main.o prog2/bar.o +
+
+ Lastly, if for some reason you don't want
+ any targets built by default,
+ you can use the Python None
+ variable:
+
+
+env = Environment() +prog1 = env.Program('prog1.c') +prog2 = env.Program('prog2.c') +Default(None) +
+ + Which would produce build output like: + +
%scons -Q
+scons: *** No targets specified and no Default() targets found. Stop. +Found nothing to build +%scons -Q .
+cc -o prog1.o -c prog1.c +cc -o prog1 prog1.o +cc -o prog2.o -c prog2.c +cc -o prog2 prog2.o +
+
+ SCons supports a DEFAULT_TARGETS
variable
+ that lets you get at the current list of default targets.
+ The DEFAULT_TARGETS
variable has
+ two important differences from the COMMAND_LINE_TARGETS
variable.
+ First, the DEFAULT_TARGETS
variable is a list of
+ internal SCons nodes,
+ so you need to convert the list elements to strings
+ if you want to print them or look for a specific target name.
+ You can do this easily by calling the str
+ on the elements in a list comprehension:
+
+
+prog1 = Program('prog1.c') +Default(prog1) +print("DEFAULT_TARGETS is %s" % [str(t) for t in DEFAULT_TARGETS]) +
+
+ (Keep in mind that all of the manipulation of the
+ DEFAULT_TARGETS
list takes place during the
+ first phase when SCons is reading up the SConscript
files,
+ which is obvious if
+ we leave off the -Q
flag when we run SCons:)
+
+
% scons
+scons: Reading SConscript files ...
+DEFAULT_TARGETS is ['prog1']
+scons: done reading SConscript files.
+scons: Building targets ...
+cc -o prog1.o -c prog1.c
+cc -o prog1 prog1.o
+scons: done building targets.
+
+
+ Second,
+ the contents of the DEFAULT_TARGETS
list change
+ in response to calls to the Default
function,
+ as you can see from the following SConstruct
file:
+
+
+prog1 = Program('prog1.c') +Default(prog1) +print("DEFAULT_TARGETS is now %s" % [str(t) for t in DEFAULT_TARGETS]) +prog2 = Program('prog2.c') +Default(prog2) +print("DEFAULT_TARGETS is now %s" % [str(t) for t in DEFAULT_TARGETS]) +
+ + Which yields the output: + +
% scons
+scons: Reading SConscript files ...
+DEFAULT_TARGETS is now ['prog1']
+DEFAULT_TARGETS is now ['prog1', 'prog2']
+scons: done reading SConscript files.
+scons: Building targets ...
+cc -o prog1.o -c prog1.c
+cc -o prog1 prog1.o
+cc -o prog2.o -c prog2.c
+cc -o prog2 prog2.o
+scons: done building targets.
+
+
+ In practice, this simply means that you
+ need to pay attention to the order in
+ which you call the Default
function
+ and refer to the DEFAULT_TARGETS
list,
+ to make sure that you don't examine the
+ list before you've added the default targets
+ you expect to find in it.
+
+
+
+ We've already been introduced to the
+ COMMAND_LINE_TARGETS
variable,
+ which contains a list of targets specified on the command line,
+ and the DEFAULT_TARGETS
variable,
+ which contains a list of targets specified
+ via calls to the Default
method or function.
+ Sometimes, however,
+ you want a list of whatever targets
+ SCons will try to build,
+ regardless of whether the targets came from the
+ command line or a Default
call.
+ You could code this up by hand, as follows:
+
+
+if COMMAND_LINE_TARGETS: + targets = COMMAND_LINE_TARGETS +else: + targets = DEFAULT_TARGETS +
+
+ SCons, however, provides a convenient
+ BUILD_TARGETS
variable
+ that eliminates the need for this by-hand manipulation.
+ Essentially, the BUILD_TARGETS
variable
+ contains a list of the command-line targets,
+ if any were specified,
+ and if no command-line targets were specified,
+ it contains a list of the targets specified
+ via the Default
method or function.
+
+
+
+ Because BUILD_TARGETS
may contain a list of SCons nodes,
+ you must convert the list elements to strings
+ if you want to print them or look for a specific target name,
+ just like the DEFAULT_TARGETS
list:
+
+
+prog1 = Program('prog1.c') +Program('prog2.c') +Default(prog1) +print ("BUILD_TARGETS is %s" % [str(t) for t in BUILD_TARGETS]) +
+
+ Notice how the value of BUILD_TARGETS
+ changes depending on whether a target is
+ specified on the command line:
+
+
%scons -Q
+BUILD_TARGETS is ['prog1'] +cc -o prog1.o -c prog1.c +cc -o prog1 prog1.o +%scons -Q prog2
+BUILD_TARGETS is ['prog2'] +cc -o prog2.o -c prog2.c +cc -o prog2 prog2.o +%scons -Q -c .
+BUILD_TARGETS is ['.'] +Removed prog1.o +Removed prog1 +Removed prog2.o +Removed prog2 +
[3]
+ The AddOption
function is,
+ in fact, implemented using a subclass
+ of the optparse.OptionParser
.
+
+
+ Once a program is built,
+ it is often appropriate to install it in another
+ directory for public use.
+ You use the Install
method
+ to arrange for a program, or any other file,
+ to be copied into a destination directory:
+
+
+env = Environment() +hello = env.Program('hello.c') +env.Install('/usr/bin', hello) +
+
+ Note, however, that installing a file is
+ still considered a type of file "build."
+ This is important when you remember that
+ the default behavior of SCons is
+ to build files in or below the current directory.
+ If, as in the example above,
+ you are installing files in a directory
+ outside of the top-level SConstruct
file's directory tree,
+ you must specify that directory
+ (or a higher directory, such as /
)
+ for it to install anything there:
+
+
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q /usr/bin
+Install file: "hello" as "/usr/bin/hello" +
+
+ It can, however, be cumbersome to remember
+ (and type) the specific destination directory
+ in which the program (or any other file)
+ should be installed.
+ This is an area where the Alias
+ function comes in handy,
+ allowing you, for example,
+ to create a pseudo-target named install
+ that can expand to the specified destination directory:
+
+
+env = Environment() +hello = env.Program('hello.c') +env.Install('/usr/bin', hello) +env.Alias('install', '/usr/bin') +
+ + This then yields the more natural + ability to install the program + in its destination as follows: + +
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q install
+Install file: "hello" as "/usr/bin/hello" +
+
+ You can install multiple files into a directory
+ simply by calling the Install
function multiple times:
+
+
+env = Environment() +hello = env.Program('hello.c') +goodbye = env.Program('goodbye.c') +env.Install('/usr/bin', hello) +env.Install('/usr/bin', goodbye) +env.Alias('install', '/usr/bin') +
+ + Or, more succinctly, listing the multiple input + files in a list + (just like you can do with any other builder): + +
+env = Environment() +hello = env.Program('hello.c') +goodbye = env.Program('goodbye.c') +env.Install('/usr/bin', [hello, goodbye]) +env.Alias('install', '/usr/bin') +
+ + Either of these two examples yields: + +
% scons -Q install
+cc -o goodbye.o -c goodbye.c
+cc -o goodbye goodbye.o
+Install file: "goodbye" as "/usr/bin/goodbye"
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+Install file: "hello" as "/usr/bin/hello"
+
+
+ The Install
method preserves the name
+ of the file when it is copied into the
+ destination directory.
+ If you need to change the name of the file
+ when you copy it, use the InstallAs
function:
+
+
+env = Environment() +hello = env.Program('hello.c') +env.InstallAs('/usr/bin/hello-new', hello) +env.Alias('install', '/usr/bin') +
+
+ This installs the hello
+ program with the name hello-new
+ as follows:
+
+
% scons -Q install
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+Install file: "hello" as "/usr/bin/hello-new"
+
+
+ Lastly, if you have multiple files that all
+ need to be installed with different file names,
+ you can either call the InstallAs
function
+ multiple times, or as a shorthand,
+ you can supply same-length lists
+ for both the target and source arguments:
+
+
+env = Environment() +hello = env.Program('hello.c') +goodbye = env.Program('goodbye.c') +env.InstallAs(['/usr/bin/hello-new', + '/usr/bin/goodbye-new'], + [hello, goodbye]) +env.Alias('install', '/usr/bin') +
+
+ In this case, the InstallAs
function
+ loops through both lists simultaneously,
+ and copies each source file into its corresponding
+ target file name:
+
+
% scons -Q install
+cc -o goodbye.o -c goodbye.c
+cc -o goodbye goodbye.o
+Install file: "goodbye" as "/usr/bin/goodbye-new"
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+Install file: "hello" as "/usr/bin/hello-new"
+
+
+ SCons provides a number of platform-independent functions,
+ called factories
,
+ that perform common file system manipulations
+ like copying, moving or deleting files and directories,
+ or making directories.
+ These functions are factories
+ because they don't perform the action
+ at the time they're called,
+ they each return an Action
object
+ that can be executed at the appropriate time.
+
+
+
+ Suppose you want to arrange to make a copy of a file,
+ and don't have a suitable pre-existing builder.
+ [4]
+ One way would be to use the Copy
action factory
+ in conjunction with the Command
builder:
+
+
+Command("file.out", "file.in", Copy("$TARGET", "$SOURCE")) +
+
+ Notice that the action returned by the Copy
factory
+ will expand the $TARGET
and $SOURCE
strings
+ at the time file.out
is built,
+ and that the order of the arguments
+ is the same as that of a builder itself--that is,
+ target first, followed by source:
+
+
% scons -Q
+Copy("file.out", "file.in")
+
+
+ You can, of course, name a file explicitly
+ instead of using $TARGET
or $SOURCE
:
+
+
+Command("file.out", [], Copy("$TARGET", "file.in")) +
+ + Which executes as: + +
% scons -Q
+Copy("file.out", "file.in")
+
+
+ The usefulness of the Copy
factory
+ becomes more apparent when
+ you use it in a list of actions
+ passed to the Command
builder.
+ For example, suppose you needed to run a
+ file through a utility that only modifies files in-place,
+ and can't "pipe" input to output.
+ One solution is to copy the source file
+ to a temporary file name,
+ run the utility,
+ and then copy the modified temporary file to the target,
+ which the Copy
factory makes extremely easy:
+
+
+Command("file.out", "file.in", + [ + Copy("tempfile", "$SOURCE"), + "modify tempfile", + Copy("$TARGET", "tempfile"), + ]) +
+ + The output then looks like: + +
% scons -Q
+Copy("tempfile", "file.in")
+modify tempfile
+Copy("file.out", "tempfile")
+
+ The Copy
factory has a third optional argument which controls
+ how symlinks are copied.
+
+
+# Symbolic link shallow copied as a new symbolic link: +Command("LinkIn", "LinkOut", Copy("$TARGET", "$SOURCE"[, True])) + +# Symbolic link target copied as a file or directory: +Command("LinkIn", "FileOrDirectoryOut", Copy("$TARGET", "$SOURCE", False)) +
+
+ If you need to delete a file,
+ then the Delete
factory
+ can be used in much the same way as
+ the Copy
factory.
+ For example, if we want to make sure that
+ the temporary file
+ in our last example doesn't exist before
+ we copy to it,
+ we could add Delete
to the beginning
+ of the command list:
+
+
+Command("file.out", "file.in", + [ + Delete("tempfile"), + Copy("tempfile", "$SOURCE"), + "modify tempfile", + Copy("$TARGET", "tempfile"), + ]) +
+ + Which then executes as follows: + +
% scons -Q
+Delete("tempfile")
+Copy("tempfile", "file.in")
+modify tempfile
+Copy("file.out", "tempfile")
+
+
+ Of course, like all of these Action
factories,
+ the Delete
factory also expands
+ $TARGET
and $SOURCE
variables appropriately.
+ For example:
+
+
+Command("file.out", "file.in", + [ + Delete("$TARGET"), + Copy("$TARGET", "$SOURCE") + ]) +
+ + Executes as: + +
% scons -Q
+Delete("file.out")
+Copy("file.out", "file.in")
+
+
+ Note, however, that you typically don't need to
+ call the Delete
factory explicitly in this way;
+ by default, SCons deletes its target(s)
+ for you before executing any action.
+
+
+
+ One word of caution about using the Delete
factory:
+ it has the same variable expansions available
+ as any other factory, including the $SOURCE
variable.
+ Specifying Delete("$SOURCE")
+ is not something you usually want to do!
+
+
+
+ The Move
factory
+ allows you to rename a file or directory.
+ For example, if we don't want to copy the temporary file,
+ we could use:
+
+
+Command("file.out", "file.in", + [ + Copy("tempfile", "$SOURCE"), + "modify tempfile", + Move("$TARGET", "tempfile"), + ]) +
+ + Which would execute as: + +
% scons -Q
+Copy("tempfile", "file.in")
+modify tempfile
+Move("file.out", "tempfile")
+
+
+ If you just need to update the
+ recorded modification time for a file,
+ use the Touch
factory:
+
+
+Command("file.out", "file.in", + [ + Copy("$TARGET", "$SOURCE"), + Touch("$TARGET"), + ]) +
+ + Which executes as: + +
% scons -Q
+Copy("file.out", "file.in")
+Touch("file.out")
+
+
+ If you need to create a directory,
+ use the Mkdir
factory.
+ For example, if we need to process
+ a file in a temporary directory
+ in which the processing tool
+ will create other files that we don't care about,
+ you could use:
+
+
+Command("file.out", "file.in", + [ + Delete("tempdir"), + Mkdir("tempdir"), + Copy("tempdir/${SOURCE.file}", "$SOURCE"), + "process tempdir", + Move("$TARGET", "tempdir/output_file"), + Delete("tempdir"), + ]) +
+ + Which executes as: + +
% scons -Q
+Delete("tempdir")
+Mkdir("tempdir")
+Copy("tempdir/file.in", "file.in")
+process tempdir
+Move("file.out", "tempdir/output_file")
+scons: *** [file.out] tempdir/output_file: No such file or directory
+
+
+ To change permissions on a file or directory,
+ use the Chmod
factory.
+ The permission argument uses POSIX-style
+ permission bits and should typically
+ be expressed as an octal,
+ not decimal, number:
+
+
+Command("file.out", "file.in", + [ + Copy("$TARGET", "$SOURCE"), + Chmod("$TARGET", 0755), + ]) +
+ + Which executes: + +
% scons -Q
+Copy("file.out", "file.in")
+Chmod("file.out", 0755)
+
+
+ We've been showing you how to use Action
factories
+ in the Command
function.
+ You can also execute an Action
returned by a factory
+ (or actually, any Action
)
+ at the time the SConscript
file is read
+ by using the Execute
function.
+ For example, if we need to make sure that
+ a directory exists before we build any targets,
+
+
+Execute(Mkdir('/tmp/my_temp_directory')) +
+
+ Notice that this will
+ create the directory while
+ the SConscript
file is being read:
+
+
% scons
+scons: Reading SConscript files ...
+Mkdir("/tmp/my_temp_directory")
+scons: done reading SConscript files.
+scons: Building targets ...
+scons: `.' is up to date.
+scons: done building targets.
+
+
+ If you're familiar with Python,
+ you may wonder why you would want to use this
+ instead of just calling the native Python
+ os.mkdir()
function.
+ The advantage here is that the Mkdir
+ action will behave appropriately if the user
+ specifies the SCons -n
or
+ -q
options--that is,
+ it will print the action but not actually
+ make the directory when -n
is specified,
+ or make the directory but not print the action
+ when -q
is specified.
+
+
+
+ The Execute
function returns the exit status
+ or return value of the underlying action being executed.
+ It will also print an error message if the action
+ fails and returns a non-zero value.
+ SCons will not, however,
+ actually stop the build if the action fails.
+ If you want the build to stop
+ in response to a failure in an action called by Execute
,
+ you must do so by explicitly
+ checking the return value
+ and calling the Exit
function
+ (or a Python equivalent):
+
+
+if Execute(Mkdir('/tmp/my_temp_directory')): + # A problem occurred while making the temp directory. + Exit(1) +
[4]
+ Unfortunately, in the early days of SCons design,
+ we used the name Copy
for the function that
+ returns a copy of the environment,
+ otherwise that would be the logical choice for
+ a Builder that copies a file or directory tree
+ to a target location.
+
+
+ There are two occasions when SCons will,
+ by default, remove target files.
+ The first is when SCons determines that
+ an target file needs to be rebuilt
+ and removes the existing version of the target
+ before executing
+ The second is when SCons is invoked with the
+ -c
option to "clean"
+ a tree of its built targets.
+
+ These behaviours can be suppressed with the
+ Precious
and NoClean
functions, respectively.
+
+
+
+ By default, SCons removes targets before building them.
+ Sometimes, however, this is not what you want.
+ For example, you may want to update a library incrementally,
+ not by having it deleted and then rebuilt from all
+ of the constituent object files.
+ In such cases, you can use the
+ Precious
method to prevent
+ SCons from removing the target before it is built:
+
+
+ env = Environment(RANLIBCOM='') + lib = env.Library('foo', ['f1.c', 'f2.c', 'f3.c']) + env.Precious(lib) +
+ + Although the output doesn't look any different, + SCons does not, in fact, + delete the target library before rebuilding it: + +
% scons -Q
+cc -o f1.o -c f1.c
+cc -o f2.o -c f2.c
+cc -o f3.o -c f3.c
+ar rc libfoo.a f1.o f2.o f3.o
+
+
+ SCons will, however, still delete files marked as Precious
+ when the -c
option is used.
+
+
+
+ By default, SCons removes all built targets when invoked
+ with the -c
option to clean a source tree
+ of built targets.
+ Sometimes, however, this is not what you want.
+ For example, you may want to remove only intermediate generated files
+ (such as object files),
+ but leave the final targets
+ (the libraries)
+ untouched.
+
+ In such cases, you can use the NoClean
method to prevent SCons
+ from removing a target during a clean:
+
+
+env = Environment(RANLIBCOM='') +lib = env.Library('foo', ['f1.c', 'f2.c', 'f3.c']) +env.NoClean(lib) +
+
+ Notice that the libfoo.a
+ is not listed as a removed file:
+
+
%scons -Q
+cc -o f1.o -c f1.c +cc -o f2.o -c f2.c +cc -o f3.o -c f3.c +ar rc libfoo.a f1.o f2.o f3.o +%scons -c
+scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Cleaning targets ... +Removed f1.o +Removed f2.o +Removed f3.o +scons: done cleaning targets. +
+
+ There may be additional files that you want removed
+ when the -c
option is used,
+ but which SCons doesn't know about
+ because they're not normal target files.
+ For example, perhaps a command you invoke
+ creates a log file as
+ part of building the target file you want.
+ You would like the log file cleaned,
+ but you don't want to have to teach
+ SCons that the command
+ "builds" two files.
+
+
+
+ You can use the Clean
function to arrange for additional files
+ to be removed when the -c
option is used.
+ Notice, however, that the Clean
function takes two arguments,
+ and the second argument
+ is the name of the additional file you want cleaned
+ (foo.log
in this example):
+
+
+t = Command('foo.out', 'foo.in', 'build -o $TARGET $SOURCE') +Clean(t, 'foo.log') +
+
+ The first argument is the target with which you want
+ the cleaning of this additional file associated.
+ In the above example,
+ we've used the return value from the
+ Command
function,
+ which represents the
+ foo.out
+ target.
+ Now whenever the
+ foo.out
target is cleaned
+ by the -c
option,
+ the foo.log
file
+ will be removed as well:
+
+
%scons -Q
+build -o foo.out foo.in +%scons -Q -c
+Removed foo.out +Removed foo.log +
+
+ The source code for large software projects
+ rarely stays in a single directory,
+ but is nearly always divided into a
+ hierarchy of directories.
+ Organizing a large software build using SCons
+ involves creating a hierarchy of build scripts
+ using the SConscript
function.
+
+
+
+ As we've already seen,
+ the build script at the top of the tree is called SConstruct
.
+ The top-level SConstruct
file can
+ use the SConscript
function to
+ include other subsidiary scripts in the build.
+ These subsidiary scripts can, in turn,
+ use the SConscript
function
+ to include still other scripts in the build.
+ By convention, these subsidiary scripts are usually
+ named SConscript
.
+ For example, a top-level SConstruct
file might
+ arrange for four subsidiary scripts to be included
+ in the build as follows:
+
+
+SConscript(['drivers/display/SConscript', + 'drivers/mouse/SConscript', + 'parser/SConscript', + 'utilities/SConscript']) +
+
+ In this case, the SConstruct
file
+ lists all of the SConscript
files in the build explicitly.
+ (Note, however, that not every directory in the tree
+ necessarily has an SConscript
file.)
+ Alternatively, the drivers
+ subdirectory might contain an intermediate
+ SConscript
file,
+ in which case the SConscript
call in
+ the top-level SConstruct
file
+ would look like:
+
+
+SConscript(['drivers/SConscript', + 'parser/SConscript', + 'utilities/SConscript']) +
+
+ And the subsidiary SConscript
file in the
+ drivers
subdirectory
+ would look like:
+
+
+SConscript(['display/SConscript', + 'mouse/SConscript']) +
+
+ Whether you list all of the SConscript
files in the
+ top-level SConstruct
file,
+ or place a subsidiary SConscript
file in
+ intervening directories,
+ or use some mix of the two schemes,
+ is up to you and the needs of your software.
+
+
+
+ Subsidiary SConscript
files make it easy to create a build
+ hierarchy because all of the file and directory names
+ in a subsidiary SConscript
files are interpreted
+ relative to the directory in which the SConscript
file lives.
+ Typically, this allows the SConscript
file containing the
+ instructions to build a target file
+ to live in the same directory as the source files
+ from which the target will be built,
+ making it easy to update how the software is built
+ whenever files are added or deleted
+ (or other changes are made).
+
+
+
+ For example, suppose we want to build two programs
+ prog1
and prog2
in two separate directories
+ with the same names as the programs.
+ One typical way to do this would be
+ with a top-level SConstruct
file like this:
+
+
+SConscript(['prog1/SConscript', + 'prog2/SConscript']) +
+
+ And subsidiary SConscript
files that look like this:
+
+
+env = Environment() +env.Program('prog1', ['main.c', 'foo1.c', 'foo2.c']) + +
+ + And this: + +
+env = Environment() +env.Program('prog2', ['main.c', 'bar1.c', 'bar2.c']) + +
+ + Then, when we run SCons in the top-level directory, + our build looks like: + +
% scons -Q
+cc -o prog1/foo1.o -c prog1/foo1.c
+cc -o prog1/foo2.o -c prog1/foo2.c
+cc -o prog1/main.o -c prog1/main.c
+cc -o prog1/prog1 prog1/main.o prog1/foo1.o prog1/foo2.o
+cc -o prog2/bar1.o -c prog2/bar1.c
+cc -o prog2/bar2.o -c prog2/bar2.c
+cc -o prog2/main.o -c prog2/main.c
+cc -o prog2/prog2 prog2/main.o prog2/bar1.o prog2/bar2.o
+
+
+ Notice the following:
+
+ First, you can have files with the same names
+ in multiple directories, like main.c in the above example.
+
+ Second, unlike standard recursive use of Make,
+ SCons stays in the top-level directory
+ (where the SConstruct
file lives)
+ and issues commands that use the path names
+ from the top-level directory to the
+ target and source files within the hierarchy.
+
+
+
+ If you need to use a file from another directory,
+ it's sometimes more convenient to specify
+ the path to a file in another directory
+ from the top-level SConstruct
directory,
+ even when you're using that file in
+ a subsidiary SConscript
file in a subdirectory.
+ You can tell SCons to interpret a path name
+ as relative to the top-level SConstruct
directory,
+ not the local directory of the SConscript
file,
+ by appending a #
(hash mark)
+ to the beginning of the path name:
+
+
+env = Environment() +env.Program('prog', ['main.c', '#lib/foo1.c', 'foo2.c']) +
+
+ In this example,
+ the lib
directory is
+ directly underneath the top-level SConstruct
directory.
+ If the above SConscript
file is in a subdirectory
+ named src/prog
,
+ the output would look like:
+
+
% scons -Q
+cc -o lib/foo1.o -c lib/foo1.c
+cc -o src/prog/foo2.o -c src/prog/foo2.c
+cc -o src/prog/main.o -c src/prog/main.c
+cc -o src/prog/prog src/prog/main.o lib/foo1.o src/prog/foo2.o
+
+
+ (Notice that the lib/foo1.o
object file
+ is built in the same directory as its source file.
+ See Chapter 15, Separating Source and Build Directories, below,
+ for information about
+ how to build the object file in a different subdirectory.)
+
+
+ + Of course, you can always specify + an absolute path name for a file--for example: + +
+env = Environment() +env.Program('prog', ['main.c', '/usr/joe/lib/foo1.c', 'foo2.c']) +
+ + Which, when executed, would yield: + +
% scons -Q
+cc -o src/prog/foo2.o -c src/prog/foo2.c
+cc -o src/prog/main.o -c src/prog/main.c
+cc -o /usr/joe/lib/foo1.o -c /usr/joe/lib/foo1.c
+cc -o src/prog/prog src/prog/main.o /usr/joe/lib/foo1.o src/prog/foo2.o
+
+
+ (As was the case with top-relative path names,
+ notice that the /usr/joe/lib/foo1.o
object file
+ is built in the same directory as its source file.
+ See Chapter 15, Separating Source and Build Directories, below,
+ for information about
+ how to build the object file in a different subdirectory.)
+
+
+
+ In the previous example,
+ each of the subsidiary SConscript
files
+ created its own construction environment
+ by calling Environment
separately.
+ This obviously works fine,
+ but if each program must be built
+ with the same construction variables,
+ it's cumbersome and error-prone to initialize
+ separate construction environments
+ in the same way over and over in each subsidiary
+ SConscript
file.
+
+
+
+ SCons supports the ability to export variables
+ from a parent SConscript
file
+ to its subsidiary SConscript
files,
+ which allows you to share common initialized
+ values throughout your build hierarchy.
+
+
+
+ There are two ways to export a variable,
+ such as a construction environment,
+ from an SConscript
file,
+ so that it may be used by other SConscript
files.
+ First, you can call the Export
+ function with a list of variables,
+ or a string of white-space separated variable names.
+ Each call to Export
adds one
+ or more variables to a global list
+ of variables that are available for import
+ by other SConscript
files.
+
+
+env = Environment() +Export('env') +
+ + You may export more than one variable name at a time: + +
+env = Environment() +debug = ARGUMENTS['debug'] +Export('env', 'debug') +
+
+ Because white space is not legal in Python variable names,
+ the Export
function will even automatically split
+ a string into separate names for you:
+
+
+Export('env debug') +
+
+ Second, you can specify a list of
+ variables to export as a second argument
+ to the SConscript
function call:
+
+
+SConscript('src/SConscript', 'env') +
+
+ Or as the exports
keyword argument:
+
+
+SConscript('src/SConscript', exports='env') +
+
+ These calls export the specified variables
+ to only the listed SConscript
files.
+ You may, however, specify more than one
+ SConscript
file in a list:
+
+
+SConscript(['src1/SConscript', + 'src2/SConscript'], exports='env') +
+
+ This is functionally equivalent to
+ calling the SConscript
function
+ multiple times with the same exports
argument,
+ one per SConscript
file.
+
+
+
+ Once a variable has been exported from a calling
+ SConscript
file,
+ it may be used in other SConscript
files
+ by calling the Import
function:
+
+
+Import('env') +env.Program('prog', ['prog.c']) +
+
+ The Import
call makes the env
construction
+ environment available to the SConscript
file,
+ after which the variable can be used to build
+ programs, libraries, etc.
+
+
+
+ Like the Export
function,
+ the Import
function can be used
+ with multiple variable names:
+
+
+Import('env', 'debug') +env = env.Clone(DEBUG = debug) +env.Program('prog', ['prog.c']) +
+
+ And the Import
function will similarly
+ split a string along white-space
+ into separate variable names:
+
+
+Import('env debug') +env = env.Clone(DEBUG = debug) +env.Program('prog', ['prog.c']) +
+
+ Lastly, as a special case,
+ you may import all of the variables that
+ have been exported by supplying an asterisk
+ to the Import
function:
+
+
+Import('*') +env = env.Clone(DEBUG = debug) +env.Program('prog', ['prog.c']) +
+
+ If you're dealing with a lot of SConscript
files,
+ this can be a lot simpler than keeping
+ arbitrary lists of imported variables in each file.
+
+
+
+ Sometimes, you would like to be able to
+ use information from a subsidiary
+ SConscript
file in some way.
+ For example,
+ suppose that you want to create one
+ library from source files
+ scattered throughout a number
+ of subsidiary SConscript
files.
+ You can do this by using the Return
+ function to return values
+ from the subsidiary SConscript
files
+ to the calling file.
+
+
+
+ If, for example, we have two subdirectories
+ foo
and bar
+ that should each contribute a source
+ file to a Library,
+ what we'd like to be able to do is
+ collect the object files
+ from the subsidiary SConscript
calls
+ like this:
+
+
+env = Environment() +Export('env') +objs = [] +for subdir in ['foo', 'bar']: + o = SConscript('%s/SConscript' % subdir) + objs.append(o) +env.Library('prog', objs) +
+
+ We can do this by using the Return
+ function in the
+ foo/SConscript
file like this:
+
+
+Import('env') +obj = env.Object('foo.c') +Return('obj') + +
+
+ (The corresponding
+ bar/SConscript
+ file should be pretty obvious.)
+ Then when we run SCons,
+ the object files from the subsidiary subdirectories
+ are all correctly archived in the desired library:
+
+
% scons -Q
+cc -o bar/bar.o -c bar/bar.c
+cc -o foo/foo.o -c foo/foo.c
+ar rc libprog.a foo/foo.o bar/bar.o
+ranlib libprog.a
+
+
+ It's often useful to keep any built files completely
+ separate from the source files.
+ In SCons, this is usually done by creating one or more separate
+ variant directory trees
+ that are used to hold the built objects files, libraries,
+ and executable programs, etc.
+ for a specific flavor, or variant, of build.
+ SCons provides two ways to do this,
+ one through the SConscript
function that we've already seen,
+ and the second through a more flexible VariantDir
function.
+
+
+
+ One historical note: the VariantDir
function
+ used to be called BuildDir
.
+ That name is still supported
+ but has been deprecated
+ because the SCons functionality
+ differs from the model of a "build directory"
+ implemented by other build systems like the GNU Autotools.
+
+
+
+ The most straightforward way to establish a variant directory tree
+ uses the fact that the usual way to
+ set up a build hierarchy is to have an
+ SConscript
file in the source subdirectory.
+ If you then pass a variant_dir
argument to the
+ SConscript
function call:
+
+
+SConscript('src/SConscript', variant_dir='build') +
+
+ SCons will then build all of the files in
+ the build
subdirectory:
+
+
%ls src
+SConscript hello.c +%scons -Q
+cc -o build/hello.o -c build/hello.c +cc -o build/hello build/hello.o +%ls build
+SConscript hello hello.c hello.o +
+
+ But wait a minute--what's going on here?
+ SCons created the object file
+ build/hello.o
+ in the build
subdirectory,
+ as expected.
+ But even though our hello.c
file lives in the src
subdirectory,
+ SCons has actually compiled a
+ build/hello.c
file
+ to create the object file.
+
+
+
+ What's happened is that SCons has duplicated
+ the hello.c
file from the src
subdirectory
+ to the build
subdirectory,
+ and built the program from there.
+ The next section explains why SCons does this.
+
+
+ + SCons duplicates source files in variant directory trees + because it's the most straightforward way to guarantee a correct build + regardless of include-file directory paths, + relative references between files, + or tool support for putting files in different locations, + and the SCons philosophy is to, by default, + guarantee a correct build in all cases. + +
+ + The most direct reason to duplicate source files + in variant directories + is simply that some tools (mostly older versions) + are written to only build their output files + in the same directory as the source files. + In this case, the choices are either + to build the output file in the source directory + and move it to the variant directory, + or to duplicate the source files in the variant directory. + +
+
+ Additionally,
+ relative references between files
+ can cause problems if we don't
+ just duplicate the hierarchy of source files
+ in the variant directory.
+ You can see this at work in
+ use of the C preprocessor #include
+ mechanism with double quotes, not angle brackets:
+
+
+#include "file.h" +
+
+ The de facto standard behavior
+ for most C compilers in this case
+ is to first look in the same directory
+ as the source file that contains the #include
line,
+ then to look in the directories in the preprocessor search path.
+ Add to this that the SCons implementation of
+ support for code repositories
+ (described below)
+ means not all of the files
+ will be found in the same directory hierarchy,
+ and the simplest way to make sure
+ that the right include file is found
+ is to duplicate the source files into the variant directory,
+ which provides a correct build
+ regardless of the original location(s) of the source files.
+
+
+ + Although source-file duplication guarantees a correct build + even in these end-cases, + it can usually be safely disabled. + The next section describes + how you can disable the duplication of source files + in the variant directory. + +
+
+ In most cases and with most tool sets,
+ SCons can place its target files in a build subdirectory
+ without
+ duplicating the source files
+ and everything will work just fine.
+ You can disable the default SCons behavior
+ by specifying duplicate=0
+ when you call the SConscript
function:
+
+
+SConscript('src/SConscript', variant_dir='build', duplicate=0) +
+ + When this flag is specified, + SCons uses the variant directory + like most people expect--that is, + the output files are placed in the variant directory + while the source files stay in the source directory: + +
+%ls src
+SConscript +hello.c +%scons -Q
+cc -c src/hello.c -o build/hello.o +cc -o build/hello build/hello.o +%ls build
+hello +hello.o +
+
+ Use the VariantDir
function to establish that target
+ files should be built in a separate directory
+ from the source files:
+
+
+VariantDir('build', 'src') +env = Environment() +env.Program('build/hello.c') +
+
+ Note that when you're not using
+ an SConscript
file in the src
subdirectory,
+ you must actually specify that
+ the program must be built from
+ the build/hello.c
+ file that SCons will duplicate in the
+ build
subdirectory.
+
+
+
+ When using the VariantDir
function directly,
+ SCons still duplicates the source files
+ in the variant directory by default:
+
+
%ls src
+hello.c +%scons -Q
+cc -o build/hello.o -c build/hello.c +cc -o build/hello build/hello.o +%ls build
+hello hello.c hello.o +
+
+ You can specify the same duplicate=0
argument
+ that you can specify for an SConscript
call:
+
+
+VariantDir('build', 'src', duplicate=0) +env = Environment() +env.Program('build/hello.c') +
+ + In which case SCons + will disable duplication of the source files: + +
%ls src
+hello.c +%scons -Q
+cc -o build/hello.o -c src/hello.c +cc -o build/hello build/hello.o +%ls build
+hello hello.o +
+
+ Even when using the VariantDir
function,
+ it's much more natural to use it with
+ a subsidiary SConscript
file.
+ For example, if the
+ src/SConscript
+ looks like this:
+
+
+env = Environment() +env.Program('hello.c') +
+
+ Then our SConstruct
file could look like:
+
+
+VariantDir('build', 'src') +SConscript('build/SConscript') + +
+ + Yielding the following output: + +
%ls src
+SConscript hello.c +%scons -Q
+cc -o build/hello.o -c build/hello.c +cc -o build/hello build/hello.o +%ls build
+SConscript hello hello.c hello.o +
+
+ Notice that this is completely equivalent
+ to the use of SConscript
that we
+ learned about in the previous section.
+
+
+
+ The Glob
file name pattern matching function
+ works just as usual when using VariantDir
.
+ For example, if the
+ src/SConscript
+ looks like this:
+
+
+env = Environment() +env.Program('hello', Glob('*.c')) +
+
+ Then with the same SConstruct
file as in the previous section,
+ and source files f1.c
+ and f2.c
in src,
+ we would see the following output:
+
+
%ls src
+SConscript f1.c f2.c f2.h +%scons -Q
+cc -o build/f1.o -c build/f1.c +cc -o build/f2.o -c build/f2.c +cc -o build/hello build/f1.o build/f2.o +%ls build
+SConscript f1.c f1.o f2.c f2.h f2.o hello +
+
+ The Glob
function returns Nodes in the
+ build/
tree, as you'd expect.
+
+
+
+ The variant_dir
keyword argument of
+ the SConscript
function provides everything
+ we need to show how easy it is to create
+ variant builds using SCons.
+ Suppose, for example, that we want to
+ build a program for both Windows and Linux platforms,
+ but that we want to build it in a shared directory
+ with separate side-by-side build directories
+ for the Windows and Linux versions of the program.
+
+
+platform = ARGUMENTS.get('OS', Platform()) + +include = "#export/$PLATFORM/include" +lib = "#export/$PLATFORM/lib" +bin = "#export/$PLATFORM/bin" + +env = Environment(PLATFORM = platform, + BINDIR = bin, + INCDIR = include, + LIBDIR = lib, + CPPPATH = [include], + LIBPATH = [lib], + LIBS = 'world') + +Export('env') + +env.SConscript('src/SConscript', variant_dir='build/$PLATFORM') +
+ + This SConstruct file, + when run on a Linux system, yields: + +
% scons -Q OS=linux
+Install file: "build/linux/world/world.h" as "export/linux/include/world.h"
+cc -o build/linux/hello/hello.o -c -Iexport/linux/include build/linux/hello/hello.c
+cc -o build/linux/world/world.o -c -Iexport/linux/include build/linux/world/world.c
+ar rc build/linux/world/libworld.a build/linux/world/world.o
+ranlib build/linux/world/libworld.a
+Install file: "build/linux/world/libworld.a" as "export/linux/lib/libworld.a"
+cc -o build/linux/hello/hello build/linux/hello/hello.o -Lexport/linux/lib -lworld
+Install file: "build/linux/hello/hello" as "export/linux/bin/hello"
+
+ + The same SConstruct file on Windows would build: + +
C:\>scons -Q OS=windows
+Install file: "build/windows/world/world.h" as "export/windows/include/world.h"
+cl /Fobuild\windows\hello\hello.obj /c build\windows\hello\hello.c /nologo /Iexport\windows\include
+cl /Fobuild\windows\world\world.obj /c build\windows\world\world.c /nologo /Iexport\windows\include
+lib /nologo /OUT:build\windows\world\world.lib build\windows\world\world.obj
+Install file: "build/windows/world/world.lib" as "export/windows/lib/world.lib"
+link /nologo /OUT:build\windows\hello\hello.exe /LIBPATH:export\windows\lib world.lib build\windows\hello\hello.obj
+embedManifestExeCheck(target, source, env)
+Install file: "build/windows/hello/hello.exe" as "export/windows/bin/hello.exe"
+
+ The gettext
toolset supports internationalization and localization
+ of SCons-based projects. Builders provided by gettext
automatize
+ generation and updates of translation files. You can manage translations and
+ translation templates similarly to how it's done with autotools.
+
+ To follow examples provided in this chapter set up your operating system to
+ support two or more languages. In following examples we use locales
+ en_US
, de_DE
, and
+ pl_PL
.
+
+ Ensure, that you have GNU gettext + utilities installed on your system. +
+ To edit translation files you may wish to install poedit editor. +
+ Let's start with a very simple project, the "Hello world" program + for example + +
+/* hello.c */ +#include <stdio.h> +int main(int argc, char* argv[]) +{ + printf("Hello world\n"); + return 0; +} +
+
+
+ Prepare a SConstruct
to compile the program
+ as usual.
+
+
+# SConstruct +env = Environment() +hello = Program(["hello.c"]) +
+ +
+ Now we'll convert the project to a multi-lingual one. If you don't
+ already have GNU gettext
+ utilities installed, install them from your preffered
+ package repository, or download from
+ http://ftp.gnu.org/gnu/gettext/. For the purpose of this example,
+ you should have following three locales installed on your system:
+ en_US
, de_DE
and
+ pl_PL
. On debian, for example, you may enable certain
+ locales through dpkg-reconfigure locales.
+
+ First prepare the hello.c
program for
+ internationalization. Change the previous code so it reads as follows:
+
+
+/* hello.c */ +#include <stdio.h> +#include <libintl.h> +#include <locale.h> +int main(int argc, char* argv[]) +{ + bindtextdomain("hello", "locale"); + setlocale(LC_ALL, ""); + textdomain("hello"); + printf(gettext("Hello world\n")); + return 0; +} +
+
+ Detailed recipes for such conversion can
+ be found at
+ http://www.gnu.org/software/gettext/manual/gettext.html#Sources.
+ The gettext("...")
has two purposes.
+ First, it marks messages for the xgettext(1) program, which
+ we will use to extract from the sources the messages for localization.
+ Second, it calls the gettext
library internals to
+ translate the message at runtime.
+
+ Now we shall instruct SCons how to generate and maintain translation files.
+ For that, use the Translate
builder and MOFiles
builder.
+ The first one takes source files, extracts internationalized
+ messages from them, creates so-called POT
file
+ (translation template), and then creates PO
translation
+ files, one for each requested language. Later, during the development
+ lifecycle, the builder keeps all these files up-to date. The
+ MOFiles
builder compiles the PO
files to binary
+ form. Then install the MO
files under directory
+ called locale
.
+
The completed
+ SConstruct
is as follows:
+
+
+# SConstruct +env = Environment( tools = ['default', 'gettext'] ) +hello = env.Program(["hello.c"]) +env['XGETTEXTFLAGS'] = [ + '--package-name=%s' % 'hello', + '--package-version=%s' % '1.0', +] +po = env.Translate(["pl","en", "de"], ["hello.c"], POAUTOINIT = 1) +mo = env.MOFiles(po) +InstallAs(["locale/en/LC_MESSAGES/hello.mo"], ["en.mo"]) +InstallAs(["locale/pl/LC_MESSAGES/hello.mo"], ["pl.mo"]) +InstallAs(["locale/de/LC_MESSAGES/hello.mo"], ["de.mo"]) +
+ +
+ Generate the translation files with scons po-update. + You should see the output from SCons simillar to this: +
+user@host:$ scons po-update +scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Building targets ... +Entering '/home/ptomulik/projects/tmp' +xgettext --package-name=hello --package-version=1.0 -o - hello.c +Leaving '/home/ptomulik/projects/tmp' +Writting 'messages.pot' (new file) +msginit --no-translator -l pl -i messages.pot -o pl.po +Created pl.po. +msginit --no-translator -l en -i messages.pot -o en.po +Created en.po. +msginit --no-translator -l de -i messages.pot -o de.po +Created de.po. +scons: done building targets. +
+
+ If everything is right, you should see following new files. +
+user@host:$ ls *.po* +de.po en.po messages.pot pl.po +
+
+ Open en.po
in poedit and provide
+ the English translation to message "Hello world\n"
. Do the
+ same for de.po
(deutsch) and
+ pl.po
(polish). Let the translations be, for example:
+
+ en: "Welcome to beautiful world!\n"
+
+ de: "Hallo Welt!\n"
+
+ pl: "Witaj swiecie!\n"
+
+
+ Now compile the project by executing scons. The + output should be similar to this: +
+user@host:$ scons +scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Building targets ... +msgfmt -c -o de.mo de.po +msgfmt -c -o en.mo en.po +gcc -o hello.o -c hello.c +gcc -o hello hello.o +Install file: "de.mo" as "locale/de/LC_MESSAGES/hello.mo" +Install file: "en.mo" as "locale/en/LC_MESSAGES/hello.mo" +msgfmt -c -o pl.mo pl.po +Install file: "pl.mo" as "locale/pl/LC_MESSAGES/hello.mo" +scons: done building targets. +
+ SCons automatically compiled the PO
files to binary format
+ MO
, and the InstallAs
lines installed
+ these files under locale
folder.
+
+ Your program should be now ready. You may try it as follows (linux): +
+user@host:$ LANG=en_US.UTF-8 ./hello +Welcome to beautiful world +
+
+user@host:$ LANG=de_DE.UTF-8 ./hello +Hallo Welt +
+
+user@host:$ LANG=pl_PL.UTF-8 ./hello +Witaj swiecie +
+
+ To demonstrate the further life of translation files, let's change Polish
+ translation (poedit pl.po) to "Witaj drogi
+ swiecie\n"
. Run scons to see how scons
+ reacts to this
+
+user@host:$scons +scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Building targets ... +msgfmt -c -o pl.mo pl.po +Install file: "pl.mo" as "locale/pl/LC_MESSAGES/hello.mo" +scons: done building targets. +
+
+ Now, open hello.c
and add another one
+ printf
line with new message.
+
+
+/* hello.c */ +#include <stdio.h> +#include <libintl.h> +#include <locale.h> +int main(int argc, char* argv[]) +{ + bindtextdomain("hello", "locale"); + setlocale(LC_ALL, ""); + textdomain("hello"); + printf(gettext("Hello world\n")); + printf(gettext("and good bye\n")); + return 0; +} +
+ +
+ Compile project with scons. This time, the
+ msgmerge(1) program is used by SCons to update
+ PO
file. The output from compilation is like:
+
+user@host:$scons +scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Building targets ... +Entering '/home/ptomulik/projects/tmp' +xgettext --package-name=hello --package-version=1.0 -o - hello.c +Leaving '/home/ptomulik/projects/tmp' +Writting 'messages.pot' (messages in file were outdated) +msgmerge --update de.po messages.pot +... done. +msgfmt -c -o de.mo de.po +msgmerge --update en.po messages.pot +... done. +msgfmt -c -o en.mo en.po +gcc -o hello.o -c hello.c +gcc -o hello hello.o +Install file: "de.mo" as "locale/de/LC_MESSAGES/hello.mo" +Install file: "en.mo" as "locale/en/LC_MESSAGES/hello.mo" +msgmerge --update pl.po messages.pot +... done. +msgfmt -c -o pl.mo pl.po +Install file: "pl.mo" as "locale/pl/LC_MESSAGES/hello.mo" +scons: done building targets. +
+
+ The next example demonstrates what happens if we change the source code
+ in such way that the internationalized messages do not change. The answer
+ is that none of translation files (POT
,
+ PO
) are touched (i.e. no content changes, no
+ creation/modification time changed and so on). Let's append another
+ line to the program (after the last printf), so its code becomes:
+
+
+/* hello.c */ +#include <stdio.h> +#include <libintl.h> +#include <locale.h> +int main(int argc, char* argv[]) +{ + bindtextdomain("hello", "locale"); + setlocale(LC_ALL, ""); + textdomain("hello"); + printf(gettext("Hello world\n")); + printf(gettext("and good bye\n")); + printf("----------------\n"); + return a; +} +
+ + Compile the project. You'll see on your screen +
+user@host:$scons +scons: Reading SConscript files ... +scons: done reading SConscript files. +scons: Building targets ... +Entering '/home/ptomulik/projects/tmp' +xgettext --package-name=hello --package-version=1.0 -o - hello.c +Leaving '/home/ptomulik/projects/tmp' +Not writting 'messages.pot' (messages in file found to be up-to-date) +gcc -o hello.o -c hello.c +gcc -o hello hello.o +scons: done building targets. +
+ As you see, the internationalized messages ditn't change, so the
+ POT
and the rest of translation files have not
+ even been touched.
+
+
+ Although SCons provides many useful methods
+ for building common software products
+ (programs, libraries, documents, etc.),
+ you frequently want to be
+ able to build some other type of file
+ not supported directly by SCons.
+ Fortunately, SCons makes it very easy
+ to define your own Builder
objects
+ for any custom file types you want to build.
+ (In fact, the SCons interfaces for creating
+ Builder
objects are flexible enough and easy enough to use
+ that all of the the SCons built-in Builder
objects
+ are created using the mechanisms described in this section.)
+
+
+
+ The simplest Builder
to create is
+ one that executes an external command.
+ For example, if we want to build
+ an output file by running the contents
+ of the input file through a command named
+ foobuild
,
+ creating that Builder
might look like:
+
+
+bld = Builder(action = 'foobuild < $SOURCE > $TARGET') +
+
+ All the above line does is create a free-standing
+ Builder
object.
+ The next section will show us how to actually use it.
+
+
+
+ A Builder
object isn't useful
+ until it's attached to a construction environment
+ so that we can call it to arrange
+ for files to be built.
+ This is done through the $BUILDERS
+ construction variable
in an environment.
+ The $BUILDERS
variable is a Python dictionary
+ that maps the names by which you want to call
+ various Builder
objects to the objects themselves.
+ For example, if we want to call the
+ Builder
we just defined by the name
+ Foo
,
+ our SConstruct
file might look like:
+
+
+bld = Builder(action = 'foobuild < $SOURCE > $TARGET') +env = Environment(BUILDERS = {'Foo' : bld}) +
+
+ With the Builder
attached to our construction environment
+ with the name Foo
,
+ we can now actually call it like so:
+
+
+env.Foo('file.foo', 'file.input') +
+ + Then when we run SCons it looks like: + +
% scons -Q
+foobuild < file.input > file.foo
+
+
+ Note, however, that the default $BUILDERS
+ variable in a construction environment
+ comes with a default set of Builder
objects
+ already defined:
+ Program
, Library
, etc.
+ And when we explicitly set the $BUILDERS
variable
+ when we create the construction environment
,
+ the default Builder
s are no longer part of
+ the environment:
+
+
+bld = Builder(action = 'foobuild < $SOURCE > $TARGET') +env = Environment(BUILDERS = {'Foo' : bld}) +env.Foo('file.foo', 'file.input') +env.Program('hello.c') +
% scons -Q
+AttributeError: 'SConsEnvironment' object has no attribute 'Program':
+ File "/home/my/project/SConstruct", line 4:
+ env.Program('hello.c')
+
+
+ To be able to use both our own defined Builder
objects
+ and the default Builder
objects in the same construction environment
,
+ you can either add to the $BUILDERS
variable
+ using the Append
function:
+
+
+env = Environment() +bld = Builder(action = 'foobuild < $SOURCE > $TARGET') +env.Append(BUILDERS = {'Foo' : bld}) +env.Foo('file.foo', 'file.input') +env.Program('hello.c') +
+
+ Or you can explicitly set the appropriately-named
+ key in the $BUILDERS
dictionary:
+
+
+env = Environment() +bld = Builder(action = 'foobuild < $SOURCE > $TARGET') +env['BUILDERS']['Foo'] = bld +env.Foo('file.foo', 'file.input') +env.Program('hello.c') +
+
+ Either way, the same construction environment
+ can then use both the newly-defined
+ Foo
Builder
+ and the default Program
Builder
:
+
+
% scons -Q
+foobuild < file.input > file.foo
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+
+
+ By supplying additional information
+ when you create a Builder
,
+ you can let SCons add appropriate file
+ suffixes to the target and/or the source file.
+ For example, rather than having to specify
+ explicitly that you want the Foo
+ Builder
to build the file.foo
+ target file from the file.input
source file,
+ you can give the .foo
+ and .input
suffixes to the Builder
,
+ making for more compact and readable calls to
+ the Foo
Builder
:
+
+
+bld = Builder(action = 'foobuild < $SOURCE > $TARGET', + suffix = '.foo', + src_suffix = '.input') +env = Environment(BUILDERS = {'Foo' : bld}) +env.Foo('file1') +env.Foo('file2') +
% scons -Q
+foobuild < file1.input > file1.foo
+foobuild < file2.input > file2.foo
+
+
+ You can also supply a prefix
keyword argument
+ if it's appropriate to have SCons append a prefix
+ to the beginning of target file names.
+
+
+
+ In SCons, you don't have to call an external command
+ to build a file.
+ You can, instead, define a Python function
+ that a Builder
object can invoke
+ to build your target file (or files).
+ Such a builder function
definition looks like:
+
+
+def build_function(target, source, env): + # Code to build "target" from "source" + return None +
+
+ The arguments of a builder function
are:
+
+
+
+ A list of Node objects representing
+ the target or targets to be
+ built by this builder function.
+ The file names of these target(s)
+ may be extracted using the Python str
function.
+
+
+
+ A list of Node objects representing
+ the sources to be
+ used by this builder function to build the targets.
+ The file names of these source(s)
+ may be extracted using the Python str
function.
+
+
+
+ The construction environment
used for building the target(s).
+ The builder function may use any of the
+ environment's construction variables
+ in any way to affect how it builds the targets.
+
+
+
+ The builder function must
+ return a 0
or None
value
+ if the target(s) are built successfully.
+ The builder function
+ may raise an exception
+ or return any non-zero value
+ to indicate that the build is unsuccessful.
+
+
+
+ Once you've defined the Python function
+ that will build your target file,
+ defining a Builder
object for it is as
+ simple as specifying the name of the function,
+ instead of an external command,
+ as the Builder
's
+ action
+ argument:
+
+
+def build_function(target, source, env): + # Code to build "target" from "source" + return None +bld = Builder(action = build_function, + suffix = '.foo', + src_suffix = '.input') +env = Environment(BUILDERS = {'Foo' : bld}) +env.Foo('file') +
+ + And notice that the output changes slightly, + reflecting the fact that a Python function, + not an external command, + is now called to build the target file: + +
% scons -Q
+build_function(["file.foo"], ["file.input"])
+
+
+ SCons Builder objects can create an action "on the fly"
+ by using a function called a generator
.
+ This provides a great deal of flexibility to
+ construct just the right list of commands
+ to build your target.
+ A generator
looks like:
+
+
+def generate_actions(source, target, env, for_signature): + return 'foobuild < %s > %s' % (target[0], source[0]) +
+
+ The arguments of a generator
are:
+
+
+
+ A list of Node objects representing
+ the sources to be built
+ by the command or other action
+ generated by this function.
+ The file names of these source(s)
+ may be extracted using the Python str
function.
+
+
+
+ A list of Node objects representing
+ the target or targets to be built
+ by the command or other action
+ generated by this function.
+ The file names of these target(s)
+ may be extracted using the Python str
function.
+
+
+
+ The construction environment
used for building the target(s).
+ The generator may use any of the
+ environment's construction variables
+ in any way to determine what command
+ or other action to return.
+
+
+ + A flag that specifies whether the + generator is being called to contribute to a build signature, + as opposed to actually executing the command. + + + +
+
+ The generator
must return a
+ command string or other action that will be used to
+ build the specified target(s) from the specified source(s).
+
+
+
+ Once you've defined a generator
,
+ you create a Builder
to use it
+ by specifying the generator keyword argument
+ instead of action
.
+
+
+def generate_actions(source, target, env, for_signature): + return 'foobuild < %s > %s' % (source[0], target[0]) +bld = Builder(generator = generate_actions, + suffix = '.foo', + src_suffix = '.input') +env = Environment(BUILDERS = {'Foo' : bld}) +env.Foo('file') +
% scons -Q
+foobuild < file.input > file.foo
+
+
+ Note that it's illegal to specify both an
+ action
+ and a
+ generator
+ for a Builder
.
+
+
+
+ SCons supports the ability for a Builder to modify the
+ lists of target(s) from the specified source(s).
+ You do this by defining an emitter
function
+ that takes as its arguments
+ the list of the targets passed to the builder,
+ the list of the sources passed to the builder,
+ and the construction environment.
+ The emitter function should return the modified
+ lists of targets that should be built
+ and sources from which the targets will be built.
+
+
+
+ For example, suppose you want to define a Builder
+ that always calls a foobuild
program,
+ and you want to automatically add
+ a new target file named
+ new_target
+ and a new source file named
+ new_source
+ whenever it's called.
+ The SConstruct
file might look like this:
+
+
+def modify_targets(target, source, env): + target.append('new_target') + source.append('new_source') + return target, source +bld = Builder(action = 'foobuild $TARGETS - $SOURCES', + suffix = '.foo', + src_suffix = '.input', + emitter = modify_targets) +env = Environment(BUILDERS = {'Foo' : bld}) +env.Foo('file') +
+ + And would yield the following output: + +
% scons -Q
+foobuild file.foo new_target - file.input new_source
+
+
+ One very flexible thing that you can do is
+ use a construction variable to specify
+ different emitter functions for different
+ construction variable.
+ To do this, specify a string
+ containing a construction variable
+ expansion as the emitter when you call
+ the Builder
function,
+ and set that construction variable to
+ the desired emitter function
+ in different construction environments:
+
+
+bld = Builder(action = './my_command $SOURCES > $TARGET', + suffix = '.foo', + src_suffix = '.input', + emitter = '$MY_EMITTER') +def modify1(target, source, env): + return target, source + ['modify1.in'] +def modify2(target, source, env): + return target, source + ['modify2.in'] +env1 = Environment(BUILDERS = {'Foo' : bld}, + MY_EMITTER = modify1) +env2 = Environment(BUILDERS = {'Foo' : bld}, + MY_EMITTER = modify2) +env1.Foo('file1') +env2.Foo('file2') +
+
+ In this example, the modify1.in
+ and modify2.in
files
+ get added to the source lists
+ of the different commands:
+
+
% scons -Q
+./my_command file1.input modify1.in > file1.foo
+./my_command file2.input modify2.in > file2.foo
+
+
+ The site_scons
directories give you a place to
+ put Python modules and packages that you can import into your SConscript
files
+ (site_scons
),
+ add-on tools that can integrate into SCons
+ (site_scons/site_tools
),
+ and a site_scons/site_init.py
file that
+ gets read before any SConstruct
or SConscript
file,
+ allowing you to change SCons's default behavior.
+
+
+ + Each system type (Windows, Mac, Linux, etc.) searches a canonical + set of directories for site_scons; see the man page for details. + The top-level SConstruct's site_scons dir is always searched last, + and its dir is placed first in the tool path so it overrides all + others. + +
+
+ If you get a tool from somewhere (the SCons wiki or a third party,
+ for instance) and you'd like to use it in your project, a
+ site_scons
dir is the simplest place to put it.
+ Tools come in two flavors; either a Python function that operates on
+ an Environment
or a Python module or package containing two functions,
+ exists()
and generate()
.
+
+
+
+ A single-function Tool can just be included in your
+ site_scons/site_init.py
file where it will be
+ parsed and made available for use. For instance, you could have a
+ site_scons/site_init.py
file like this:
+
+
+def TOOL_ADD_HEADER(env): + """A Tool to add a header from $HEADER to the source file""" + add_header = Builder(action=['echo "$HEADER" > $TARGET', + 'cat $SOURCE >> $TARGET']) + env.Append(BUILDERS = {'AddHeader' : add_header}) + env['HEADER'] = '' # set default value +
+
+ and a SConstruct
like this:
+
+
+# Use TOOL_ADD_HEADER from site_scons/site_init.py +env=Environment(tools=['default', TOOL_ADD_HEADER], HEADER="=====") +env.AddHeader('tgt', 'src') +
+
+ The TOOL_ADD_HEADER
tool method will be
+ called to add the AddHeader
tool to the
+ environment.
+
+
+ A more full-fledged tool with
+ exists()
and generate()
+ methods can be installed either as a module in the file
+ site_scons/site_tools/toolname.py
or as a
+ package in the
+ directory site_scons/site_tools/toolname
. In
+ the case of using a package, the exists()
+ and generate()
are in the
+ file site_scons/site_tools/toolname/__init__.py
.
+ (In all the above case toolname
is replaced
+ by the name of the tool.)
+ Since site_scons/site_tools
is automatically
+ added to the head of the tool search path, any tool found there
+ will be available to all environments. Furthermore, a tool found
+ there will override a built-in tool of the same name, so if you
+ need to change the behavior of a built-in
+ tool, site_scons
gives you the hook you need.
+
+ Many people have a library of utility Python functions they'd like
+ to include in SConscript
s; just put that module in
+ site_scons/my_utils.py
or any valid Python module name of your
+ choice. For instance you can do something like this in
+ site_scons/my_utils.py
to add
+ build_id
and MakeWorkDir
+ functions:
+
+from SCons.Script import * # for Execute and Mkdir +def build_id(): + """Return a build ID (stub version)""" + return "100" +def MakeWorkDir(workdir): + """Create the specified dir immediately""" + Execute(Mkdir(workdir)) +
+
+ And then in your SConscript
or any sub-SConscript
anywhere in
+ your build, you can import my_utils
and use it:
+
+
+import my_utils +print("build_id=" + my_utils.build_id()) +my_utils.MakeWorkDir('/tmp/work') +
+ Note that although you can put this library in
+ site_scons/site_init.py
,
+ it is no better there than site_scons/my_utils.py
+ since you still have to import that module into your SConscript
.
+ Also note that in order to refer to objects in the SCons namespace
+ such as Environment
or Mkdir
or Execute
in any file other
+ than a SConstruct
or SConscript
you always need to do
+
+from SCons.Script import * +
+ This is true in modules in site_scons
such as
+ site_scons/site_init.py
as well.
+
+
+ You can use any of the user- or machine-wide site dirs such as
+ ~/.scons/site_scons
instead of
+ ./site_scons
, or use the
+ --site-dir
option to point to your own dir.
+ site_init.py
and
+ site_tools
will be located under that dir.
+ To avoid using a site_scons
dir at all,
+ even if it exists, use the --no-site-dir
+ option.
+
+
+
+ Creating a Builder
and attaching it to a construction environment
+ allows for a lot of flexibility when you
+ want to re-use actions
+ to build multiple files of the same type.
+ This can, however, be cumbersome
+ if you only need to execute one specific command
+ to build a single file (or group of files).
+ For these situations, SCons supports a
+ Command
Builder
that arranges
+ for a specific action to be executed
+ to build a specific file or files.
+ This looks a lot like the other builders
+ (like Program
, Object
, etc.),
+ but takes as an additional argument
+ the command to be executed to build the file:
+
+
+env = Environment() +env.Command('foo.out', 'foo.in', "sed 's/x/y/' < $SOURCE > $TARGET") +
+
+ When executed,
+ SCons runs the specified command,
+ substituting $SOURCE
and $TARGET
+ as expected:
+
+
% scons -Q
+sed 's/x/y/' < foo.in > foo.out
+
+
+ This is often more convenient than
+ creating a Builder
object
+ and adding it to the $BUILDERS
variable
+ of a construction environment
+
+
+
+ Note that the action you specify to the
+ Command
Builder
can be any legal SCons Action
,
+ such as a Python function:
+
+
+env = Environment() +def build(target, source, env): + # Whatever it takes to build + return None +env.Command('foo.out', 'foo.in', build) +
+ + Which executes as follows: + +
% scons -Q
+build(["foo.out"], ["foo.in"])
+
+
+ Note that $SOURCE
and $TARGET
are expanded
+ in the source and target as well as of SCons 1.1,
+ so you can write:
+
+
+env.Command('${SOURCE.basename}.out', 'foo.in', build) +
+ + which does the same thing as the previous example, but allows you + to avoid repeating yourself. + +
+
+ The AddMethod
function is used to add a method
+ to an environment. It's typically used to add a "pseudo-builder,"
+ a function that looks like a Builder
but
+ wraps up calls to multiple other Builder
s
+ or otherwise processes its arguments
+ before calling one or more Builder
s.
+ In the following example,
+ we want to install the program into the standard
+ /usr/bin
directory hierarchy,
+ but also copy it into a local install/bin
+ directory from which a package might be built:
+
+
+def install_in_bin_dirs(env, source): + """Install source in both bin dirs""" + i1 = env.Install("$BIN", source) + i2 = env.Install("$LOCALBIN", source) + return [i1[0], i2[0]] # Return a list, like a normal builder +env = Environment(BIN='/usr/bin', LOCALBIN='#install/bin') +env.AddMethod(install_in_bin_dirs, "InstallInBinDirs") +env.InstallInBinDirs(Program('hello.c')) # installs hello in both bin dirs +
+ This produces the following: +
% scons -Q /
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+Install file: "hello" as "/usr/bin/hello"
+Install file: "hello" as "install/bin/hello"
+
+
+ As mentioned, a pseudo-builder also provides more flexibility
+ in parsing arguments than you can get with a Builder
.
+ The next example shows a pseudo-builder with a
+ named argument that modifies the filename, and a separate argument
+ for the resource file (rather than having the builder figure it out
+ by file extension). This example also demonstrates using the global
+ AddMethod
function to add a method to the global Environment class,
+ so it will be used in all subsequently created environments.
+
+
+def BuildTestProg(env, testfile, resourcefile, testdir="tests"): + """Build the test program; + prepends "test_" to src and target, + and puts target into testdir.""" + srcfile = "test_%s.c" % testfile + target = "%s/test_%s" % (testdir, testfile) + if env['PLATFORM'] == 'win32': + resfile = env.RES(resourcefile) + p = env.Program(target, [srcfile, resfile]) + else: + p = env.Program(target, srcfile) + return p +AddMethod(Environment, BuildTestProg) + +env = Environment() +env.BuildTestProg('stuff', resourcefile='res.rc') +
+ This produces the following on Linux: +
% scons -Q
+cc -o test_stuff.o -c test_stuff.c
+cc -o tests/test_stuff test_stuff.o
+
+ And the following on Windows: +
C:\>scons -Q
+rc /fores.res res.rc
+cl /Fotest_stuff.obj /c test_stuff.c /nologo
+link /nologo /OUT:tests\test_stuff.exe test_stuff.obj res.res
+embedManifestExeCheck(target, source, env)
+
+ Using AddMethod
is better than just adding an instance method
+ to a construction environment
because it gets called as a proper method,
+ and because AddMethod
provides for copying the method
+ to any clones of the construction environment
instance.
+
+
+ SCons has built-in scanners that know how to look in
+ C, Fortran and IDL source files for information about
+ other files that targets built from those files depend on--for example,
+ in the case of files that use the C preprocessor,
+ the .h
files that are specified
+ using #include
lines in the source.
+ You can use the same mechanisms that SCons uses to create
+ its built-in scanners to write scanners of your own for file types
+ that SCons does not know how to scan "out of the box."
+
+
+
+ Suppose, for example, that we want to create a simple scanner
+ for .foo
files.
+ A .foo
file contains some text that
+ will be processed,
+ and can include other files on lines that begin
+ with include
+ followed by a file name:
+
+
+include filename.foo +
+
+ Scanning a file will be handled by a Python function
+ that you must supply.
+ Here is a function that will use the Python
+ re
module
+ to scan for the include
lines in our example:
+
+
+import re + +include_re = re.compile(r'^include\s+(\S+)$', re.M) + +def kfile_scan(node, env, path, arg): + contents = node.get_text_contents() + return env.File(include_re.findall(contents)) +
+
+ It is important to note that you
+ have to return a list of File nodes from the scanner function, simple
+ strings for the file names won't do. As in the examples we are showing here,
+ you can use the File
+ function of your current Environment in order to create nodes on the fly from
+ a sequence of file names with relative paths.
+
+
+ + The scanner function must + accept the four specified arguments + and return a list of implicit dependencies. + Presumably, these would be dependencies found + from examining the contents of the file, + although the function can perform any + manipulation at all to generate the list of + dependencies. + +
+
+ An SCons node object representing the file being scanned.
+ The path name to the file can be
+ used by converting the node to a string
+ using the str()
function,
+ or an internal SCons get_text_contents()
+ object method can be used to fetch the contents.
+
+
+ + The construction environment in effect for this scan. + The scanner function may choose to use construction + variables from this environment to affect its behavior. + +
+
+ A list of directories that form the search path for included files
+ for this scanner.
+ This is how SCons handles the $CPPPATH
and $LIBPATH
+ variables.
+
+
+ + An optional argument that you can choose to + have passed to this scanner function by + various scanner instances. + +
+
+ A Scanner object is created using the Scanner
function,
+ which typically takes an skeys
argument
+ to associate the type of file suffix with this scanner.
+ The Scanner object must then be associated with the
+ $SCANNERS
construction variable of a construction environment,
+ typically by using the Append
method:
+
+
+kscan = Scanner(function = kfile_scan, + skeys = ['.k']) +env.Append(SCANNERS = kscan) +
+ + When we put it all together, it looks like: + +
+ import re + + include_re = re.compile(r'^include\s+(\S+)$', re.M) + + def kfile_scan(node, env, path): + contents = node.get_text_contents() + includes = include_re.findall(contents) + return env.File(includes) + + kscan = Scanner(function = kfile_scan, + skeys = ['.k']) + + env = Environment(ENV = {'PATH' : '/usr/local/bin'}) + env.Append(SCANNERS = kscan) + + env.Command('foo', 'foo.k', 'kprocess < $SOURCES > $TARGET') +
+
+ Many scanners need to search for included files or dependencies
+ using a path variable; this is how $CPPPATH
and
+ $LIBPATH
work. The path to search is passed to your
+ scanner as the path
argument. Path variables
+ may be lists of nodes, semicolon-separated strings, or even
+ contain SCons variables which need to be expanded. Fortunately,
+ SCons provides the FindPathDirs
function which itself returns
+ a function to expand a given path (given as a SCons construction
+ variable name) to a list of paths at the time the scanner is
+ called. Deferring evaluation until that point allows, for
+ instance, the path to contain $TARGET references which differ for
+ each file scanned.
+
+
+
+ Using FindPathDirs
is quite easy. Continuing the above example,
+ using KPATH as the construction variable with the search path
+ (analogous to $CPPPATH
), we just modify the Scanner
+ constructor call to include a path keyword arg:
+
+
+kscan = Scanner(function = kfile_scan, + skeys = ['.k'], + path_function = FindPathDirs('KPATH')) +
+ + FindPathDirs returns a callable object that, when called, will + essentially expand the elements in env['KPATH'] and tell the + scanner to search in those dirs. It will also properly add + related repository and variant dirs to the search list. As a side + note, the returned method stores the path in an efficient way so + lookups are fast even when variable substitutions may be needed. + This is important since many files get scanned in a typical build. + +
+
+ One approach for the use of scanners is with builders.
+ There are two optional parameters we can use with a builder
+ source_scanner
and target_scanner
.
+
+
+ +def kfile_scan(node, env, path, arg): + contents = node.get_text_contents() + return env.File(include_re.findall(contents)) + +kscan = Scanner(function = kfile_scan, + skeys = ['.k'], + path_function = FindPathDirs('KPATH')) + +def build_function(target, source, env): + # Code to build "target" from "source" + return None + +bld = Builder(action = build_function, + suffix = '.foo', + source_scanner = kscan + src_suffix = '.input') +env = Environment(BUILDERS = {'Foo' : bld}) +env.Foo('file') + +
+ + An emitter function can modify the list of sources or targets + passed to the action function when the builder is triggered. + +
+ + A scanner function will not affect the list of sources or targets + seen by the builder during the build action. The scanner function + will however affect if the builder should be rebuilt (if any of + the files sourced by the scanner have changed for example). + +
+ + Often, a software project will have + one or more central repositories, + directory trees that contain + source code, or derived files, or both. + You can eliminate additional unnecessary + rebuilds of files by having SCons + use files from one or more code repositories + to build files in your local build tree. + +
+
+ It's often useful to allow multiple programmers working
+ on a project to build software from
+ source files and/or derived files that
+ are stored in a centrally-accessible repository,
+ a directory copy of the source code tree.
+ (Note that this is not the sort of repository
+ maintained by a source code management system
+ like BitKeeper, CVS, or Subversion.)
+
+ You use the Repository
method
+ to tell SCons to search one or more
+ central code repositories (in order)
+ for any source files and derived files
+ that are not present in the local build tree:
+
+
+env = Environment() +env.Program('hello.c') +Repository('/usr/repository1', '/usr/repository2') +
+
+ Multiple calls to the Repository
method
+ will simply add repositories to the global list
+ that SCons maintains,
+ with the exception that SCons will automatically eliminate
+ the current directory and any non-existent
+ directories from the list.
+
+
+
+ The above example
+ specifies that SCons
+ will first search for files under
+ the /usr/repository1
tree
+ and next under the /usr/repository2
tree.
+ SCons expects that any files it searches
+ for will be found in the same position
+ relative to the top-level directory.
+ In the above example, if the hello.c
file is not
+ found in the local build tree,
+ SCons will search first for
+ a /usr/repository1/hello.c
file
+ and then for a /usr/repository2/hello.c
file
+ to use in its place.
+
+
+
+ So given the SConstruct
file above,
+ if the hello.c
file exists in the local
+ build directory,
+ SCons will rebuild the hello
program
+ as normal:
+
+
% scons -Q
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+
+
+ If, however, there is no local hello.c
file,
+ but one exists in /usr/repository1
,
+ SCons will recompile the hello
program
+ from the source file it finds in the repository:
+
+
% scons -Q
+cc -o hello.o -c /usr/repository1/hello.c
+cc -o hello hello.o
+
+
+ And similarly, if there is no local hello.c
file
+ and no /usr/repository1/hello.c
,
+ but one exists in /usr/repository2
:
+
+
% scons -Q
+cc -o hello.o -c /usr/repository2/hello.c
+cc -o hello hello.o
+
+ +
+
+ We've already seen that SCons will scan the contents of
+ a source file for #include
file names
+ and realize that targets built from that source file
+ also depend on the #include
file(s).
+ For each directory in the $CPPPATH
list,
+ SCons will actually search the corresponding directories
+ in any repository trees and establish the
+ correct dependencies on any
+ #include
files that it finds
+ in repository directory.
+
+
+
+ Unless the C compiler also knows about these directories
+ in the repository trees, though,
+ it will be unable to find the #include
files.
+ If, for example, the hello.c
file in
+ our previous example includes the hello.h
+ in its current directory,
+ and the hello.h
only exists in the repository:
+
+
+% scons -Q
+cc -o hello.o -c hello.c
+hello.c:1: hello.h: No such file or directory
+
+
+ In order to inform the C compiler about the repositories,
+ SCons will add appropriate
+ -I
flags to the compilation commands
+ for each directory in the $CPPPATH
list.
+ So if we add the current directory to the
+ construction environment $CPPPATH
like so:
+
+
+env = Environment(CPPPATH = ['.']) +env.Program('hello.c') +Repository('/usr/repository1') +
+ + Then re-executing SCons yields: + +
% scons -Q
+cc -o hello.o -c -I. -I/usr/repository1 hello.c
+cc -o hello hello.o
+
+
+ The order of the -I
options replicates,
+ for the C preprocessor,
+ the same repository-directory search path
+ that SCons uses for its own dependency analysis.
+ If there are multiple repositories and multiple $CPPPATH
+ directories, SCons will add the repository directories
+ to the beginning of each $CPPPATH
directory,
+ rapidly multiplying the number of -I
flags.
+ If, for example, the $CPPPATH
contains three directories
+ (and shorter repository path names!):
+
+
+env = Environment(CPPPATH = ['dir1', 'dir2', 'dir3']) +env.Program('hello.c') +Repository('/r1', '/r2') +
+
+ Then we'll end up with nine -I
options
+ on the command line,
+ three (for each of the $CPPPATH
directories)
+ times three (for the local directory plus the two repositories):
+
+
% scons -Q
+cc -o hello.o -c -Idir1 -I/r1/dir1 -I/r2/dir1 -Idir2 -I/r1/dir2 -I/r2/dir2 -Idir3 -I/r1/dir3 -I/r2/dir3 hello.c
+cc -o hello hello.o
+
+
+ SCons relies on the C compiler's
+ -I
options to control the order in which
+ the preprocessor will search the repository directories
+ for #include
files.
+ This causes a problem, however, with how the C preprocessor
+ handles #include
lines with
+ the file name included in double-quotes.
+
+
+
+ As we've seen,
+ SCons will compile the hello.c
file from
+ the repository if it doesn't exist in
+ the local directory.
+ If, however, the hello.c
file in the repository contains
+ a #include
line with the file name in
+ double quotes:
+
+
+#include "hello.h" +int +main(int argc, char *argv[]) +{ + printf(HELLO_MESSAGE); + return (0); +} +
+
+ Then the C preprocessor will always
+ use a hello.h
file from the repository directory first,
+ even if there is a hello.h
file in the local directory,
+ despite the fact that the command line specifies
+ -I
as the first option:
+
+
% scons -Q
+cc -o hello.o -c -I. -I/usr/repository1 /usr/repository1/hello.c
+cc -o hello hello.o
+
+
+ This behavior of the C preprocessor--always search
+ for a #include
file in double-quotes
+ first in the same directory as the source file,
+ and only then search the -I
--can
+ not, in general, be changed.
+ In other words, it's a limitation
+ that must be lived with if you want to use
+ code repositories in this way.
+ There are three ways you can possibly
+ work around this C preprocessor behavior:
+
+
+
+ Some modern versions of C compilers do have an option
+ to disable or control this behavior.
+ If so, add that option to $CFLAGS
+ (or $CXXFLAGS
or both) in your construction environment(s).
+ Make sure the option is used for all construction
+ environments that use C preprocessing!
+
+
+
+ Change all occurrences of #include "file.h"
+ to #include <file.h>
.
+ Use of #include
with angle brackets
+ does not have the same behavior--the -I
+ directories are searched first
+ for #include
files--which
+ gives SCons direct control over the list of
+ directories the C preprocessor will search.
+
+
+ + Require that everyone working with compilation from + repositories check out and work on entire directories of files, + not individual files. + (If you use local wrapper scripts around + your source code control system's command, + you could add logic to enforce this restriction there. + +
+
+ SCons will also search in repositories
+ for the SConstruct
file and any specified SConscript
files.
+ This poses a problem, though: how can SCons search a
+ repository tree for an SConstruct
file
+ if the SConstruct
file itself contains the information
+ about the pathname of the repository?
+ To solve this problem, SCons allows you
+ to specify repository directories
+ on the command line using the -Y
option:
+
+
+% scons -Q -Y /usr/repository1 -Y /usr/repository2
+
+
+ When looking for source or derived files,
+ SCons will first search the repositories
+ specified on the command line,
+ and then search the repositories
+ specified in the SConstruct
or SConscript
files.
+
+
+
+ If a repository contains not only source files,
+ but also derived files (such as object files,
+ libraries, or executables), SCons will perform
+ its normal MD5 signature calculation to
+ decide if a derived file in a repository is up-to-date,
+ or the derived file must be rebuilt in the local build directory.
+ For the SCons signature calculation to work correctly,
+ a repository tree must contain the .sconsign
files
+ that SCons uses to keep track of signature information.
+
+
+
+ Usually, this would be done by a build integrator
+ who would run SCons in the repository
+ to create all of its derived files and .sconsign
files,
+ or who would run SCons in a separate build directory
+ and copy the resulting tree to the desired repository:
+
+
%cd /usr/repository1
+%scons -Q
+cc -o file1.o -c file1.c +cc -o file2.o -c file2.c +cc -o hello.o -c hello.c +cc -o hello hello.o file1.o file2.o +
+
+ (Note that this is safe even if the SConstruct
file
+ lists /usr/repository1
as a repository,
+ because SCons will remove the current build directory
+ from its repository list for that invocation.)
+
+
+
+ Now, with the repository populated,
+ we only need to create the one local source file
+ we're interested in working with at the moment,
+ and use the -Y
option to
+ tell SCons to fetch any other files it needs
+ from the repository:
+
+
+%cd $HOME/build
+%edit hello.c
+%scons -Q -Y /usr/repository1
+cc -c -o hello.o hello.c +cc -o hello hello.o /usr/repository1/file1.o /usr/repository1/file2.o +
+
+ Notice that SCons realizes that it does not need to
+ rebuild local copies file1.o
and file2.o
files,
+ but instead uses the already-compiled files
+ from the repository.
+
+
+ + If the repository tree contains the complete results of a build, + and we try to build from the repository + without any files in our local tree, + something moderately surprising happens: + +
+%mkdir $HOME/build2
+%cd $HOME/build2
+%scons -Q -Y /usr/all/repository hello
+scons: `hello' is up-to-date. +
+
+ Why does SCons say that the hello
program
+ is up-to-date when there is no hello
program
+ in the local build directory?
+ Because the repository (not the local directory)
+ contains the up-to-date hello
program,
+ and SCons correctly determines that nothing
+ needs to be done to rebuild that
+ up-to-date copy of the file.
+
+
+
+ There are, however, many times when you want to ensure that a
+ local copy of a file always exists.
+ A packaging or testing script, for example,
+ may assume that certain generated files exist locally.
+ To tell SCons to make a copy of any up-to-date repository
+ file in the local build directory,
+ use the Local
function:
+
+
+env = Environment() +hello = env.Program('hello.c') +Local(hello) +
+ + If we then run the same command, + SCons will make a local copy of the program + from the repository copy, + and tell you that it is doing so: + +
+% scons -Y /usr/all/repository hello
+Local copy of hello from /usr/all/repository/hello
+scons: `hello' is up-to-date.
+
+
+ (Notice that, because the act of making the local copy
+ is not considered a "build" of the hello
file,
+ SCons still reports that it is up-to-date.)
+
+
+ + SCons has integrated support for multi-platform build configuration + similar to that offered by GNU Autoconf, + such as + figuring out what libraries or header files + are available on the local system. + This section describes how to use + this SCons feature. + +
+ This chapter is still under development, + so not everything is explained as well as it should be. + See the SCons man page for additional information. +
+
+ The basic framework for multi-platform build configuration
+ in SCons is to attach a configure context
to a
+ construction environment by calling the Configure
function,
+ perform a number of checks for
+ libraries, functions, header files, etc.,
+ and to then call the configure context's Finish
method
+ to finish off the configuration:
+
+
+env = Environment() +conf = Configure(env) +# Checks for libraries, header files, etc. go here! +env = conf.Finish() +
+ + SCons provides a number of basic checks, + as well as a mechanism for adding your own custom checks. + +
+ + Note that SCons uses its own dependency + mechanism to determine when a check + needs to be run--that is, + SCons does not run the checks + every time it is invoked, + but caches the values returned by previous checks + and uses the cached values unless something has changed. + This saves a tremendous amount + of developer time while working on + cross-platform build issues. + +
+ + The next sections describe + the basic checks that SCons supports, + as well as how to add your own custom checks. + +
+
+ Testing the existence of a header file
+ requires knowing what language the header file is.
+ A configure context has a CheckCHeader
method
+ that checks for the existence of a C header file:
+
+
+env = Environment() +conf = Configure(env) +if not conf.CheckCHeader('math.h'): + print 'Math.h must be installed!' + Exit(1) +if conf.CheckCHeader('foo.h'): + conf.env.Append('-DHAS_FOO_H') +env = conf.Finish() +
+ + Note that you can choose to terminate + the build if a given header file doesn't exist, + or you can modify the construction environment + based on the existence of a header file. + +
+
+ If you need to check for the existence
+ a C++ header file,
+ use the CheckCXXHeader
method:
+
+
+env = Environment() +conf = Configure(env) +if not conf.CheckCXXHeader('vector.h'): + print 'vector.h must be installed!' + Exit(1) +env = conf.Finish() +
+
+ Check for the availability of a specific function
+ using the CheckFunc
method:
+
+
+env = Environment() +conf = Configure(env) +if not conf.CheckFunc('strcpy'): + print 'Did not find strcpy(), using local version' + conf.env.Append(CPPDEFINES = '-Dstrcpy=my_local_strcpy') +env = conf.Finish() +
+
+ Check for the availability of a library
+ using the CheckLib
method.
+ You only specify the basename of the library,
+ you don't need to add a lib
+ prefix or a .a
or .lib
suffix:
+
+
+env = Environment() +conf = Configure(env) +if not conf.CheckLib('m'): + print 'Did not find libm.a or m.lib, exiting!' + Exit(1) +env = conf.Finish() +
+
+ Because the ability to use a library successfully
+ often depends on having access to a header file
+ that describes the library's interface,
+ you can check for a library
+ and a header file
+ at the same time by using the
+ CheckLibWithHeader
method:
+
+
+env = Environment() +conf = Configure(env) +if not conf.CheckLibWithHeader('m', 'math.h', 'c'): + print 'Did not find libm.a or m.lib, exiting!' + Exit(1) +env = conf.Finish() +
+
+ This is essentially shorthand for
+ separate calls to the CheckHeader
and CheckLib
+ functions.
+
+
+
+ Check for the availability of a typedef
+ by using the CheckType
method:
+
+
+env = Environment() +conf = Configure(env) +if not conf.CheckType('off_t'): + print 'Did not find off_t typedef, assuming int' + conf.env.Append(CCFLAGS = '-Doff_t=int') +env = conf.Finish() +
+
+ You can also add a string that will be
+ placed at the beginning of the test file
+ that will be used to check for the typedef
.
+ This provide a way to specify
+ files that must be included to find the typedef
:
+
+
+env = Environment() +conf = Configure(env) +if not conf.CheckType('off_t', '#include <sys/types.h>\n'): + print 'Did not find off_t typedef, assuming int' + conf.env.Append(CCFLAGS = '-Doff_t=int') +env = conf.Finish() +
+ Check the size of a datatype by using the CheckTypeSize
method:
+
+env = Environment() +conf = Configure(env) +int_size = conf.CheckTypeSize('unsigned int') +print 'sizeof unsigned int is', int_size +env = conf.Finish() +
+% scons -Q
+sizeof unsigned int is 4
+scons: `.' is up to date.
+
+
+ Check for the presence of a program
+ by using the CheckProg
method:
+
+
+env = Environment() +conf = Configure(env) +if not conf.CheckProg('foobar'): + print 'Unable to find the program foobar on the system' + Exit(1) +env = conf.Finish() +
+ + A custom check is a Python function + that checks for a certain condition to exist + on the running system, + usually using methods that SCons + supplies to take care of the details + of checking whether a compilation succeeds, + a link succeeds, + a program is runnable, + etc. + A simple custom check for the existence of + a specific library might look as follows: + +
+mylib_test_source_file = """ +#include <mylib.h> +int main(int argc, char **argv) +{ + MyLibrary mylib(argc, argv); + return 0; +} +""" + +def CheckMyLibrary(context): + context.Message('Checking for MyLibrary...') + result = context.TryLink(mylib_test_source_file, '.c') + context.Result(result) + return result +
+
+ The Message
and Result
methods
+ should typically begin and end a custom check to
+ let the user know what's going on:
+ the Message
call prints the
+ specified message (with no trailing newline)
+ and the Result
call prints
+ yes
if the check succeeds and
+ no
if it doesn't.
+ The TryLink
method
+ actually tests for whether the
+ specified program text
+ will successfully link.
+
+
+
+ (Note that a custom check can modify
+ its check based on any arguments you
+ choose to pass it,
+ or by using or modifying the configure context environment
+ in the context.env
attribute.)
+
+
+
+ This custom check function is
+ then attached to the configure context
+ by passing a dictionary
+ to the Configure
call
+ that maps a name of the check
+ to the underlying function:
+
+
+env = Environment() +conf = Configure(env, custom_tests = {'CheckMyLibrary' : CheckMyLibrary}) +
+ + You'll typically want to make + the check and the function name the same, + as we've done here, + to avoid potential confusion. + +
+
+ We can then put these pieces together
+ and actually call the CheckMyLibrary
check
+ as follows:
+
+
+mylib_test_source_file = """ +#include <mylib.h> +int main(int argc, char **argv) +{ + MyLibrary mylib(argc, argv); + return 0; +} +""" + +def CheckMyLibrary(context): + context.Message('Checking for MyLibrary... ') + result = context.TryLink(mylib_test_source_file, '.c') + context.Result(result) + return result + +env = Environment() +conf = Configure(env, custom_tests = {'CheckMyLibrary' : CheckMyLibrary}) +if not conf.CheckMyLibrary(): + print 'MyLibrary is not installed!' + Exit(1) +env = conf.Finish() + +# We would then add actual calls like Program() to build +# something using the "env" construction environment. +
+ + If MyLibrary is not installed on the system, + the output will look like: + +
+% scons
+scons: Reading SConscript file ...
+Checking for MyLibrary... no
+MyLibrary is not installed!
+
+ + If MyLibrary is installed, + the output will look like: + +
+% scons
+scons: Reading SConscript file ...
+Checking for MyLibrary... yes
+scons: done reading SConscript
+scons: Building targets ...
+ .
+ .
+ .
+
+
+ Using multi-platform configuration
+ as described in the previous sections
+ will run the configuration commands
+ even when invoking
+ scons -c
+ to clean targets:
+
+
+% scons -Q -c
+Checking for MyLibrary... yes
+Removed foo.o
+Removed foo
+
+
+ Although running the platform checks
+ when removing targets doesn't hurt anything,
+ it's usually unnecessary.
+ You can avoid this by using the
+ GetOption
method to
+ check whether the -c
(clean)
+ option has been invoked on the command line:
+
+
+env = Environment() +if not env.GetOption('clean'): + conf = Configure(env, custom_tests = {'CheckMyLibrary' : CheckMyLibrary}) + if not conf.CheckMyLibrary(): + print 'MyLibrary is not installed!' + Exit(1) + env = conf.Finish() +
+% scons -Q -c
+Removed foo.o
+Removed foo
+
+ + On multi-developer software projects, + you can sometimes speed up every developer's builds a lot by + allowing them to share the derived files that they build. + SCons makes this easy, as well as reliable. + +
+
+ To enable sharing of derived files,
+ use the CacheDir
function
+ in any SConscript
file:
+
+
+CacheDir('/usr/local/build_cache') +
+ + Note that the directory you specify must already exist + and be readable and writable by all developers + who will be sharing derived files. + It should also be in some central location + that all builds will be able to access. + In environments where developers are using separate systems + (like individual workstations) for builds, + this directory would typically be + on a shared or NFS-mounted file system. + +
+
+ Here's what happens:
+ When a build has a CacheDir
specified,
+ every time a file is built,
+ it is stored in the shared cache directory
+ along with its MD5 build signature.
+ [5]
+ On subsequent builds,
+ before an action is invoked to build a file,
+ SCons will check the shared cache directory
+ to see if a file with the exact same build
+ signature already exists.
+ If so, the derived file will not be built locally,
+ but will be copied into the local build directory
+ from the shared cache directory,
+ like so:
+
+
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q -c
+Removed hello.o +Removed hello +%scons -Q
+Retrieved `hello.o' from cache +Retrieved `hello' from cache +
+
+ Note that the CacheDir
feature still calculates
+ MD5 build sigantures for the shared cache file names
+ even if you configure SCons to use timestamps
+ to decide if files are up to date.
+ (See the Chapter 6, Dependencies
+ chapter for information about the Decider
function.)
+ Consequently, using CacheDir
may reduce or eliminate any
+ potential performance improvements
+ from using timestamps for up-to-date decisions.
+
+
+ + One potential drawback to using a shared cache + is that the output printed by SCons + can be inconsistent from invocation to invocation, + because any given file may be rebuilt one time + and retrieved from the shared cache the next time. + This can make analyzing build output more difficult, + especially for automated scripts that + expect consistent output each time. + +
+
+ If, however, you use the --cache-show
option,
+ SCons will print the command line that it
+ would have executed
+ to build the file,
+ even when it is retrieving the file from the shared cache.
+ This makes the build output consistent
+ every time the build is run:
+
+
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q -c
+Removed hello.o +Removed hello +%scons -Q --cache-show
+cc -o hello.o -c hello.c +cc -o hello hello.o +
+ + The trade-off, of course, is that you no longer + know whether or not SCons + has retrieved a derived file from cache + or has rebuilt it locally. + +
+
+ You may want to disable caching for certain
+ specific files in your configuration.
+ For example, if you only want to put
+ executable files in a central cache,
+ but not the intermediate object files,
+ you can use the NoCache
+ function to specify that the
+ object files should not be cached:
+
+
+env = Environment() +obj = env.Object('hello.c') +env.Program('hello.c') +CacheDir('cache') +NoCache('hello.o') +
+
+ Then when you run scons
after cleaning
+ the built targets,
+ it will recompile the object file locally
+ (since it doesn't exist in the shared cache directory),
+ but still realize that the shared cache directory
+ contains an up-to-date executable program
+ that can be retrieved instead of re-linking:
+
+
+%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q -c
+Removed hello.o +Removed hello +%scons -Q
+cc -o hello.o -c hello.c +Retrieved `hello' from cache +
+ + Retrieving an already-built file + from the shared cache + is usually a significant time-savings + over rebuilding the file, + but how much of a savings + (or even whether it saves time at all) + can depend a great deal on your + system or network configuration. + For example, retrieving cached files + from a busy server over a busy network + might end up being slower than + rebuilding the files locally. + +
+
+ In these cases, you can specify
+ the --cache-disable
+ command-line option to tell SCons
+ to not retrieve already-built files from the
+ shared cache directory:
+
+
%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q -c
+Removed hello.o +Removed hello +%scons -Q
+Retrieved `hello.o' from cache +Retrieved `hello' from cache +%scons -Q -c
+Removed hello.o +Removed hello +%scons -Q --cache-disable
+cc -o hello.o -c hello.c +cc -o hello hello.o +
+ + Sometimes, you may have one or more derived files + already built in your local build tree + that you wish to make available to other people doing builds. + For example, you may find it more effective to perform + integration builds with the cache disabled + (per the previous section) + and only populate the shared cache directory + with the built files after the integration build + has completed successfully. + This way, the cache will only get filled up + with derived files that are part of a complete, successful build + not with files that might be later overwritten + while you debug integration problems. + +
+
+ In this case, you can use the
+ the --cache-force
option
+ to tell SCons to put all derived files in the cache,
+ even if the files already exist in your local tree
+ from having been built by a previous invocation:
+
+
%scons -Q --cache-disable
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q -c
+Removed hello.o +Removed hello +%scons -Q --cache-disable
+cc -o hello.o -c hello.c +cc -o hello hello.o +%scons -Q --cache-force
+scons: `.' is up to date. +%scons -Q
+scons: `.' is up to date. +
+
+ Notice how the above sample run
+ demonstrates that the --cache-disable
+ option avoids putting the built
+ hello.o
+ and
+ hello
files in the cache,
+ but after using the --cache-force
option,
+ the files have been put in the cache
+ for the next invocation to retrieve.
+
+
+ + If you allow multiple builds to update the + shared cache directory simultaneously, + two builds that occur at the same time + can sometimes start "racing" + with one another to build the same files + in the same order. + If, for example, + you are linking multiple files into an executable program: + +
+Program('prog', + ['f1.c', 'f2.c', 'f3.c', 'f4.c', 'f5.c']) +
+ + SCons will normally build the input object files + on which the program depends in their normal, sorted order: + +
% scons -Q
+cc -o f3.o -c f3.c
+cc -o f4.o -c f4.c
+cc -o f1.o -c f1.c
+cc -o f5.o -c f5.c
+cc -o f2.o -c f2.c
+cc -o prog f1.o f2.o f3.o f4.o f5.o
+
+
+ But if two such builds take place simultaneously,
+ they may each look in the cache at nearly the same
+ time and both decide that f1.o
+ must be rebuilt and pushed into the shared cache directory,
+ then both decide that f2.o
+ must be rebuilt (and pushed into the shared cache directory),
+ then both decide that f3.o
+ must be rebuilt...
+ This won't cause any actual build problems--both
+ builds will succeed,
+ generate correct output files,
+ and populate the cache--but
+ it does represent wasted effort.
+
+
+
+ To alleviate such contention for the cache,
+ you can use the --random
command-line option
+ to tell SCons to build dependencies
+ in a random order:
+
+
+ % scons -Q --random
+ cc -o f3.o -c f3.c
+ cc -o f1.o -c f1.c
+ cc -o f5.o -c f5.c
+ cc -o f2.o -c f2.c
+ cc -o f4.o -c f4.c
+ cc -o prog f1.o f2.o f3.o f4.o f5.o
+
+
+ Multiple builds using the --random
option
+ will usually build their dependencies in different,
+ random orders,
+ which minimizes the chances for a lot of
+ contention for same-named files
+ in the shared cache directory.
+ Multiple simultaneous builds might still race to try to build
+ the same target file on occasion,
+ but long sequences of inefficient contention
+ should be rare.
+
+
+
+ Note, of course,
+ the --random
option
+ will cause the output that SCons prints
+ to be inconsistent from invocation to invocation,
+ which may be an issue when
+ trying to compare output from different build runs.
+
+
+
+ If you want to make sure dependencies will be built
+ in a random order without having to specify
+ the --random
on very command line,
+ you can use the SetOption
function to
+ set the random
option
+ within any SConscript
file:
+
+
+SetOption('random', 1) +Program('prog', + ['f1.c', 'f2.c', 'f3.c', 'f4.c', 'f5.c']) +
[5] + Actually, the MD5 signature is used as the name of the file + in the shared cache directory in which the contents are stored. +
+
+ We've already seen how you can use the Alias
+ function to create a target named install
:
+
+
+env = Environment() +hello = env.Program('hello.c') +env.Install('/usr/bin', hello) +env.Alias('install', '/usr/bin') +
+ + You can then use this alias on the command line + to tell SCons more naturally that you want to install files: + +
% scons -Q install
+cc -o hello.o -c hello.c
+cc -o hello hello.o
+Install file: "hello" as "/usr/bin/hello"
+
+
+ Like other Builder
methods, though,
+ the Alias
method returns an object
+ representing the alias being built.
+ You can then use this object as input to anothother Builder
.
+ This is especially useful if you use such an object
+ as input to another call to the Alias
Builder
,
+ allowing you to create a hierarchy
+ of nested aliases:
+
+
+env = Environment() +p = env.Program('foo.c') +l = env.Library('bar.c') +env.Install('/usr/bin', p) +env.Install('/usr/lib', l) +ib = env.Alias('install-bin', '/usr/bin') +il = env.Alias('install-lib', '/usr/lib') +env.Alias('install', [ib, il]) +
+
+ This example defines separate install
,
+ install-bin
,
+ and install-lib
aliases,
+ allowing you finer control over what gets installed:
+
+
%scons -Q install-bin
+cc -o foo.o -c foo.c +cc -o foo foo.o +Install file: "foo" as "/usr/bin/foo" +%scons -Q install-lib
+cc -o bar.o -c bar.c +ar rc libbar.a bar.o +ranlib libbar.a +Install file: "libbar.a" as "/usr/lib/libbar.a" +%scons -Q -c /
+Removed foo.o +Removed foo +Removed /usr/bin/foo +Removed bar.o +Removed libbar.a +Removed /usr/lib/libbar.a +%scons -Q install
+cc -o foo.o -c foo.c +cc -o foo foo.o +Install file: "foo" as "/usr/bin/foo" +cc -o bar.o -c bar.c +ar rc libbar.a bar.o +ranlib libbar.a +Install file: "libbar.a" as "/usr/lib/libbar.a" +
+ + So far, we've been using examples of + building C and C++ programs + to demonstrate the features of SCons. + SCons also supports building Java programs, + but Java builds are handled slightly differently, + which reflects the ways in which + the Java compiler and tools + build programs differently than + other languages' tool chains. + +
+
+ The basic activity when programming in Java,
+ of course, is to take one or more .java
files
+ containing Java source code
+ and to call the Java compiler
+ to turn them into one or more
+ .class
files.
+ In SCons, you do this
+ by giving the Java
Builder
+ a target directory in which
+ to put the .class
files,
+ and a source directory that contains
+ the .java
files:
+
+
+Java('classes', 'src') +
+
+ If the src
directory contains
+ three .java
source files,
+ then running SCons might look like this:
+
+
% scons -Q
+javac -d classes -sourcepath src src/Example1.java src/Example2.java src/Example3.java
+
+
+ SCons will actually search the src
+ directory tree for all of the .java
files.
+ The Java compiler will then create the
+ necessary class files in the classes
subdirectory,
+ based on the class names found in the .java
files.
+
+
+
+ In addition to searching the source directory for
+ .java
files,
+ SCons actually runs the .java
files
+ through a stripped-down Java parser that figures out
+ what classes are defined.
+ In other words, SCons knows,
+ without you having to tell it,
+ what .class
files
+ will be produced by the javac call.
+ So our one-liner example from the preceding section:
+
+
+Java('classes', 'src') +
+
+ Will not only tell you reliably
+ that the .class
files
+ in the classes
subdirectory
+ are up-to-date:
+
+
%scons -Q
+javac -d classes -sourcepath src src/Example1.java src/Example2.java src/Example3.java +%scons -Q classes
+scons: `classes' is up to date. +
+
+ But it will also remove all of the generated
+ .class
files,
+ even for inner classes,
+ without you having to specify them manually.
+ For example, if our
+ Example1.java
+ and
+ Example3.java
+ files both define additional classes,
+ and the class defined in Example2.java
+ has an inner class,
+ running scons -c
+ will clean up all of those .class
files
+ as well:
+
+
%scons -Q
+javac -d classes -sourcepath src src/Example1.java src/Example2.java src/Example3.java +%scons -Q -c classes
+Removed classes/Example1.class +Removed classes/AdditionalClass1.class +Removed classes/Example2$Inner2.class +Removed classes/Example2.class +Removed classes/Example3.class +Removed classes/AdditionalClass3.class +
+
+ To ensure correct handling of .class
+ dependencies in all cases, you need to tell SCons which Java
+ version is being used. This is needed because Java 1.5 changed
+ the .class
file names for nested anonymous
+ inner classes. Use the JAVAVERSION
construction
+ variable to specify the version in use. With Java 1.6, the
+ one-liner example can then be defined like this:
+
+
+Java('classes', 'src', JAVAVERSION='1.6') +
+ See JAVAVERSION
in the man page for more information.
+
+
+ After building the class files,
+ it's common to collect them into
+ a Java archive (.jar
) file,
+ which you do by calling the Jar
Builder method.
+ If you want to just collect all of the
+ class files within a subdirectory,
+ you can just specify that subdirectory
+ as the Jar
source:
+
+
+Java(target = 'classes', source = 'src') +Jar(target = 'test.jar', source = 'classes') +
+
+ SCons will then pass that directory
+ to the jar command,
+ which will collect all of the underlying
+ .class
files:
+
+
% scons -Q
+javac -d classes -sourcepath src src/Example1.java src/Example2.java src/Example3.java
+jar cf test.jar classes
+
+
+ If you want to keep all of the
+ .class
files
+ for multiple programs in one location,
+ and only archive some of them in
+ each .jar
file,
+ you can pass the Jar
builder a
+ list of files as its source.
+ It's extremely simple to create multiple
+ .jar
files this way,
+ using the lists of target class files created
+ by calls to the Java
builder
+ as sources to the various Jar
calls:
+
+
+prog1_class_files = Java(target = 'classes', source = 'prog1') +prog2_class_files = Java(target = 'classes', source = 'prog2') +Jar(target = 'prog1.jar', source = prog1_class_files) +Jar(target = 'prog2.jar', source = prog2_class_files) +
+
+ This will then create
+ prog1.jar
+ and prog2.jar
+ next to the subdirectories
+ that contain their .java
files:
+
+
% scons -Q
+javac -d classes -sourcepath prog1 prog1/Example1.java prog1/Example2.java
+javac -d classes -sourcepath prog2 prog2/Example3.java prog2/Example4.java
+jar cf prog1.jar -C classes Example1.class -C classes Example2.class
+jar cf prog2.jar -C classes Example3.class -C classes Example4.class
+
+
+ You can generate C header and source files
+ for implementing native methods,
+ by using the JavaH
Builder.
+ There are several ways of using the JavaH
Builder.
+ One typical invocation might look like:
+
+
+classes = Java(target = 'classes', source = 'src/pkg/sub') +JavaH(target = 'native', source = classes) +
+
+ The source is a list of class files generated by the
+ call to the Java
Builder,
+ and the target is the output directory in
+ which we want the C header files placed.
+ The target
+ gets converted into the -d
+ when SCons runs javah:
+
+
% scons -Q
+javac -d classes -sourcepath src/pkg/sub src/pkg/sub/Example1.java src/pkg/sub/Example2.java src/pkg/sub/Example3.java
+javah -d native -classpath classes pkg.sub.Example1 pkg.sub.Example2 pkg.sub.Example3
+
+
+ In this case,
+ the call to javah
+ will generate the header files
+ native/pkg_sub_Example1.h
,
+ native/pkg_sub_Example2.h
+ and
+ native/pkg_sub_Example3.h
.
+ Notice that SCons remembered that the class
+ files were generated with a target directory of
+ classes
,
+ and that it then specified that target directory
+ as the -classpath
option
+ to the call to javah.
+
+
+
+ Although it's more convenient to use
+ the list of class files returned by
+ the Java
Builder
+ as the source of a call to the JavaH
Builder,
+ you can
+ specify the list of class files
+ by hand, if you prefer.
+ If you do,
+ you need to set the
+ $JAVACLASSDIR
construction variable
+ when calling JavaH
:
+
+
+Java(target = 'classes', source = 'src/pkg/sub') +class_file_list = ['classes/pkg/sub/Example1.class', + 'classes/pkg/sub/Example2.class', + 'classes/pkg/sub/Example3.class'] +JavaH(target = 'native', source = class_file_list, JAVACLASSDIR = 'classes') +
+
+ The $JAVACLASSDIR
value then
+ gets converted into the -classpath
+ when SCons runs javah:
+
+
% scons -Q
+javac -d classes -sourcepath src/pkg/sub src/pkg/sub/Example1.java src/pkg/sub/Example2.java src/pkg/sub/Example3.java
+javah -d native -classpath classes pkg.sub.Example1 pkg.sub.Example2 pkg.sub.Example3
+
+
+ Lastly, if you don't want a separate header file
+ generated for each source file,
+ you can specify an explicit File Node
+ as the target of the JavaH
Builder:
+
+
+classes = Java(target = 'classes', source = 'src/pkg/sub') +JavaH(target = File('native.h'), source = classes) +
+
+ Because SCons assumes by default
+ that the target of the JavaH
builder is a directory,
+ you need to use the File
function
+ to make sure that SCons doesn't
+ create a directory named native.h
.
+ When a file is used, though,
+ SCons correctly converts the file name
+ into the javah -o
option:
+
+
% scons -Q
+javac -d classes -sourcepath src/pkg/sub src/pkg/sub/Example1.java src/pkg/sub/Example2.java src/pkg/sub/Example3.java
+javah -o native.h -classpath classes pkg.sub.Example1 pkg.sub.Example2 pkg.sub.Example3
+
+
+ You can generate Remote Method Invocation stubs
+ by using the RMIC
Builder.
+ The source is a list of directories,
+ typically returned by a call to the Java
Builder,
+ and the target is an output directory
+ where the _Stub.class
+ and _Skel.class
files will
+ be placed:
+
+
+classes = Java(target = 'classes', source = 'src/pkg/sub') +RMIC(target = 'outdir', source = classes) +
+
+ As it did with the JavaH
Builder,
+ SCons remembers the class directory
+ and passes it as the -classpath
option
+ to rmic:
+
+
% scons -Q
+javac -d classes -sourcepath src/pkg/sub src/pkg/sub/Example1.java src/pkg/sub/Example2.java
+rmic -d outdir -classpath classes pkg.sub.Example1 pkg.sub.Example2
+
+
+ This example would generate the files
+ outdir/pkg/sub/Example1_Skel.class
,
+ outdir/pkg/sub/Example1_Stub.class
,
+ outdir/pkg/sub/Example2_Skel.class
and
+ outdir/pkg/sub/Example2_Stub.class
.
+
+
+ + SCons supports a lot of additional functionality + that doesn't readily fit into the other chapters. + +
+
+ Although the SCons code itself will run
+ on any 2.x Python version 2.7 or later,
+ you are perfectly free to make use of
+ Python syntax and modules from later versions
+ when writing your SConscript
files
+ or your own local modules.
+ If you do this, it's usually helpful to
+ configure SCons to exit gracefully with an error message
+ if it's being run with a version of Python
+ that simply won't work with your code.
+ This is especially true if you're going to use SCons
+ to build source code that you plan to distribute publicly,
+ where you can't be sure of the Python version
+ that an anonymous remote user might use
+ to try to build your software.
+
+
+
+ SCons provides an EnsurePythonVersion
function for this.
+ You simply pass it the major and minor versions
+ numbers of the version of Python you require:
+
+
+EnsurePythonVersion(2, 5) +
+ + And then SCons will exit with the following error + message when a user runs it with an unsupported + earlier version of Python: + +
+% scons -Q
+Python 2.5 or greater required, but you have Python 2.3.6
+
+
+ You may, of course, write your SConscript
files
+ to use features that were only added in
+ recent versions of SCons.
+ When you publicly distribute software that is built using SCons,
+ it's helpful to have SCons
+ verify the version being used and
+ exit gracefully with an error message
+ if the user's version of SCons won't work
+ with your SConscript
files.
+ SCons provides an EnsureSConsVersion
function
+ that verifies the version of SCons
+ in the same
+ the EnsurePythonVersion
function
+ verifies the version of Python,
+ by passing in the major and minor versions
+ numbers of the version of SCons you require:
+
+
+EnsureSConsVersion(1, 0) +
+ + And then SCons will exit with the following error + message when a user runs it with an unsupported + earlier version of SCons: + +
+% scons -Q
+SCons 1.0 or greater required, but you have SCons 0.98.5
+
+
+ SCons supports an Exit
function
+ which can be used to terminate SCons
+ while reading the SConscript
files,
+ usually because you've detected a condition
+ under which it doesn't make sense to proceed:
+
+
+if ARGUMENTS.get('FUTURE'): + print("The FUTURE option is not supported yet!") + Exit(2) +env = Environment() +env.Program('hello.c') +
%scons -Q FUTURE=1
+The FUTURE option is not supported yet! +%scons -Q
+cc -o hello.o -c hello.c +cc -o hello hello.o +
+
+ The Exit
function takes as an argument
+ the (numeric) exit status that you want SCons to exit with.
+ If you don't specify a value,
+ the default is to exit with 0
,
+ which indicates successful execution.
+
+
+
+ Note that the Exit
function
+ is equivalent to calling the Python
+ sys.exit
function
+ (which the it actually calls),
+ but because Exit
is a SCons function,
+ you don't have to import the Python
+ sys
module to use it.
+
+
+
+ The FindFile
function searches for a file in a list of directories.
+ If there is only one directory, it can be given as a simple string.
+ The function returns a File node if a matching file exists,
+ or None if no file is found.
+ (See the documentation for the Glob
function for an alternative way
+ of searching for entries in a directory.)
+
+
+# one directory +print("%s"%FindFile('missing', '.')) +t = FindFile('exists', '.') +print("%s %s"%(t.__class__, t)) +
% scons -Q
+None
+<class 'SCons.Node.FS.File'> exists
+scons: `.' is up to date.
+
+# several directories +includes = [ '.', 'include', 'src/include'] +headers = [ 'nonesuch.h', 'config.h', 'private.h', 'dist.h'] +for hdr in headers: + print('%-12s: %s'%(hdr, FindFile(hdr, includes))) +
% scons -Q
+nonesuch.h : None
+config.h : config.h
+private.h : src/include/private.h
+dist.h : include/dist.h
+scons: `.' is up to date.
+
+ + If the file exists in more than one directory, + only the first occurrence is returned. + +
+print(FindFile('multiple', ['sub1', 'sub2', 'sub3'])) +print(FindFile('multiple', ['sub2', 'sub3', 'sub1'])) +print(FindFile('multiple', ['sub3', 'sub1', 'sub2'])) +
% scons -Q
+sub1/multiple
+sub2/multiple
+sub3/multiple
+scons: `.' is up to date.
+
+
+ In addition to existing files, FindFile
will also find derived files
+ (that is, non-leaf files) that haven't been built yet.
+ (Leaf files should already exist, or the build will fail!)
+
+
+# Neither file exists, so build will fail +Command('derived', 'leaf', 'cat >$TARGET $SOURCE') +print(FindFile('leaf', '.')) +print(FindFile('derived', '.')) +
% scons -Q
+leaf
+derived
+cat > derived leaf
+
+# Only 'leaf' exists +Command('derived', 'leaf', 'cat >$TARGET $SOURCE') +print(FindFile('leaf', '.')) +print(FindFile('derived', '.')) +
% scons -Q
+leaf
+derived
+cat > derived leaf
+
+
+ If a source file exists, FindFile
will correctly return the name
+ in the build directory.
+
+
+# Only 'src/leaf' exists +VariantDir('build', 'src') +print(FindFile('leaf', 'build')) +
% scons -Q
+build/leaf
+scons: `.' is up to date.
+
+
+ SCons supports a Flatten
function
+ which takes an input Python sequence
+ (list or tuple)
+ and returns a flattened list
+ containing just the individual elements of
+ the sequence.
+ This can be handy when trying to examine
+ a list composed of the lists
+ returned by calls to various Builders.
+ For example, you might collect
+ object files built in different ways
+ into one call to the Program
Builder
+ by just enclosing them in a list, as follows:
+
+
+objects = [ + Object('prog1.c'), + Object('prog2.c', CCFLAGS='-DFOO'), +] +Program(objects) +
+ + Because the Builder calls in SCons + flatten their input lists, + this works just fine to build the program: + +
% scons -Q
+cc -o prog1.o -c prog1.c
+cc -o prog2.o -c -DFOO prog2.c
+cc -o prog1 prog1.o prog2.o
+
+
+ But if you were debugging your build
+ and wanted to print the absolute path
+ of each object file in the
+ objects
list,
+ you might try the following simple approach,
+ trying to print each Node's
+ abspath
+ attribute:
+
+
+objects = [ + Object('prog1.c'), + Object('prog2.c', CCFLAGS='-DFOO'), +] +Program(objects) + +for object_file in objects: + print(object_file.abspath) +
+
+ This does not work as expected
+ because each call to str
+ is operating an embedded list returned by
+ each Object
call,
+ not on the underlying Nodes within those lists:
+
+
% scons -Q
+AttributeError: 'NodeList' object has no attribute 'abspath':
+ File "/home/my/project/SConstruct", line 8:
+ print(object_file.abspath)
+
+
+ The solution is to use the Flatten
function
+ so that you can pass each Node to
+ the str
separately:
+
+
+objects = [ + Object('prog1.c'), + Object('prog2.c', CCFLAGS='-DFOO'), +] +Program(objects) + +for object_file in Flatten(objects): + print(object_file.abspath) +
+% scons -Q
+/home/me/project/prog1.o
+/home/me/project/prog2.o
+cc -o prog1.o -c prog1.c
+cc -o prog2.o -c -DFOO prog2.c
+cc -o prog1 prog1.o prog2.o
+
+
+ If you need to find the directory from
+ which the user invoked the scons
command,
+ you can use the GetLaunchDir
function:
+
+
+env = Environment( + LAUNCHDIR = GetLaunchDir(), +) +env.Command('directory_build_info', + '$LAUNCHDIR/build_info' + Copy('$TARGET', '$SOURCE')) +
+
+ Because SCons is usually invoked from the top-level
+ directory in which the SConstruct
file lives,
+ the Python os.getcwd()
+ is often equivalent.
+ However, the SCons
+ -u
,
+ -U
+ and
+ -D
+ command-line options,
+ when invoked from a subdirectory,
+ will cause SCons to change to the directory
+ in which the SConstruct
file is found.
+ When those options are used,
+ GetLaunchDir
will still return the path to the
+ user's invoking subdirectory,
+ allowing the SConscript
configuration
+ to still get at configuration (or other) files
+ from the originating directory.
+
+
+ + Virtualenv is a tool to create isolated Python environments. + A python application (such as SCons) may be executed within + an activated virtualenv. The activation of virtualenv modifies + current environment by defining some virtualenv-specific variables + and modifying search PATH, such that executables installed within + virtualenv's home directory are preferred over the ones installed + outside of it. + +
+ + Normally, SCons uses hard-coded PATH when searching for external + executables, so it always picks-up executables from these pre-defined + locations. This applies also to python interpreter, which is invoked + by some custom SCons tools or test suites. This means, when running + SCons in a virtualenv, an eventual invocation of python interpreter from + SCons script will most probably jump out of virtualenv and execute + python executable found in hard-coded SCons PATH, not the one which is + executing SCons. Some users may consider this as an inconsistency. + +
+ This issue may be overcome by using --enable-virtualenv
+ option. The option automatically imports virtualenv-related environment
+ variables to all created construction environment env['ENV']
,
+ and modifies SCons PATH appropriately to prefer virtualenv's executables.
+ Setting environment variable SCONS_ENABLE_VIRTUALENV=1
+ will have same effect. If virtualenv support is enabled system-vide
+ by the environment variable, it may be suppressed with
+ --ignore-virtualenv
option.
+
+ Inside of SConscript, a global function Virtualenv
is
+ available. It returns a path to virtualenv's home directory, or
+ None
if SCons is not running from virtualenv. Note,
+ that this function returns a path even if SCons is run from an
+ unactivated virtualenv.
+
+ + The experience of configuring any + software build tool to build a large code base + usually, at some point, + involves trying to figure out why + the tool is behaving a certain way, + and how to get it to behave the way you want. + SCons is no different. + This appendix contains a number of + different ways in which you can + get some additional insight into SCons' behavior. + +
+ + Note that we're always interested in trying to + improve how you can troubleshoot configuration problems. + If you run into a problem that has + you scratching your head, + and which there just doesn't seem to be a good way to debug, + odds are pretty good that someone else will run into + the same problem, too. + If so, please let the SCons development team know + (preferably by filing a bug report + or feature request at our project pages at tigris.org) + so that we can use your feedback + to try to come up with a better way to help you, + and others, get the necessary insight into SCons behavior + to help identify and fix configuration issues. + +
+ + Let's look at a simple example of + a misconfigured build + that causes a target to be rebuilt + every time SCons is run: + +
+# Intentionally misspell the output file name in the +# command used to create the file: +Command('file.out', 'file.in', 'cp $SOURCE file.oout') +
+
+ (Note to Windows users: The POSIX cp command
+ copies the first file named on the command line
+ to the second file.
+ In our example, it copies the file.in
file
+ to the file.out
file.)
+
+
+ + Now if we run SCons multiple times on this example, + we see that it re-runs the cp + command every time: + +
%scons -Q
+cp file.in file.oout +%scons -Q
+cp file.in file.oout +%scons -Q
+cp file.in file.oout +
+
+ In this example,
+ the underlying cause is obvious:
+ we've intentionally misspelled the output file name
+ in the cp command,
+ so the command doesn't actually
+ build the file.out
file that we've told SCons to expect.
+ But if the problem weren't obvious,
+ it would be helpful
+ to specify the --debug=explain
option
+ on the command line
+ to have SCons tell us very specifically
+ why it's decided to rebuild the target:
+
+
% scons -Q --debug=explain
+scons: building `file.out' because it doesn't exist
+cp file.in file.oout
+
+ + If this had been a more complicated example + involving a lot of build output, + having SCons tell us that + it's trying to rebuild the target file + because it doesn't exist + would be an important clue + that something was wrong with + the command that we invoked to build it. + +
+ Note that you can also use --warn=target-not-built which checks + whether or not expected targets exist after a build rule is + executed. +
% scons -Q --warn=target-not-built
+cp file.in file.oout
+
+scons: warning: Cannot find target file.out after building
+File "/home/bdbaddog/scons/git/as_scons/src/script/scons.py", line 204, in <module>
+
+
+ The --debug=explain
option also comes in handy
+ to help figure out what input file changed.
+ Given a simple configuration that builds
+ a program from three source files,
+ changing one of the source files
+ and rebuilding with the --debug=explain
+ option shows very specifically
+ why SCons rebuilds the files that it does:
+
+
%scons -Q
+cc -o file1.o -c file1.c +cc -o file2.o -c file2.c +cc -o file3.o -c file3.c +cc -o prog file1.o file2.o file3.o +% [CHANGE THE CONTENTS OF file2.c] +%scons -Q --debug=explain
+scons: rebuilding `file2.o' because `file2.c' changed +cc -o file2.o -c file2.c +scons: rebuilding `prog' because `file2.o' changed +cc -o prog file1.o file2.o file3.o +
+
+ This becomes even more helpful
+ in identifying when a file is rebuilt
+ due to a change in an implicit dependency,
+ such as an incuded .h
file.
+ If the file1.c
+ and file3.c
files
+ in our example
+ both included a hello.h
file,
+ then changing that included file
+ and re-running SCons with the --debug=explain
option
+ will pinpoint that it's the change to the included file
+ that starts the chain of rebuilds:
+
+
%scons -Q
+cc -o file1.o -c -I. file1.c +cc -o file2.o -c -I. file2.c +cc -o file3.o -c -I. file3.c +cc -o prog file1.o file2.o file3.o +% [CHANGE THE CONTENTS OF hello.h] +%scons -Q --debug=explain
+scons: rebuilding `file1.o' because `hello.h' changed +cc -o file1.o -c -I. file1.c +scons: rebuilding `file3.o' because `hello.h' changed +cc -o file3.o -c -I. file3.c +scons: rebuilding `prog' because: + `file1.o' changed + `file3.o' changed +cc -o prog file1.o file2.o file3.o +
+
+ (Note that the --debug=explain
option will only tell you
+ why SCons decided to rebuild necessary targets.
+ It does not tell you what files it examined
+ when deciding not
+ to rebuild a target file,
+ which is often a more valuable question to answer.)
+
+
+
+ When you create a construction environment,
+ SCons populates it
+ with construction variables that are set up
+ for various compilers, linkers and utilities
+ that it finds on your system.
+ Although this is usually helpful and what you want,
+ it might be frustrating if SCons
+ doesn't set certain variables that you
+ expect to be set.
+ In situations like this,
+ it's sometimes helpful to use the
+ construction environment Dump
method
+ to print all or some of
+ the construction variables.
+ Note that the Dump
method
+ returns
+ the representation of the variables
+ in the environment
+ for you to print (or otherwise manipulate):
+
+
+env = Environment() +print env.Dump() +
+ + On a POSIX system with gcc installed, + this might generate: + +
% scons
+scons: Reading SConscript files ...
+{ 'BUILDERS': {'_InternalInstall': <function InstallBuilderWrapper at 0x700000>, '_InternalInstallVersionedLib': <function InstallVersionedBuilderWrapper at 0x700000>, '_InternalInstallAs': <function InstallAsBuilderWrapper at 0x700000>},
+ 'CONFIGUREDIR': '#/.sconf_temp',
+ 'CONFIGURELOG': '#/config.log',
+ 'CPPSUFFIXES': [ '.c',
+ '.C',
+ '.cxx',
+ '.cpp',
+ '.c++',
+ '.cc',
+ '.h',
+ '.H',
+ '.hxx',
+ '.hpp',
+ '.hh',
+ '.F',
+ '.fpp',
+ '.FPP',
+ '.m',
+ '.mm',
+ '.S',
+ '.spp',
+ '.SPP',
+ '.sx'],
+ 'DSUFFIXES': ['.d'],
+ 'Dir': <SCons.Defaults.Variable_Method_Caller object at 0x700000>,
+ 'Dirs': <SCons.Defaults.Variable_Method_Caller object at 0x700000>,
+ 'ENV': { 'PATH': '/usr/local/bin:/opt/bin:/bin:/usr/bin'},
+ 'ESCAPE': <function escape at 0x700000>,
+ 'File': <SCons.Defaults.Variable_Method_Caller object at 0x700000>,
+ 'HOST_ARCH': None,
+ 'HOST_OS': None,
+ 'IDLSUFFIXES': ['.idl', '.IDL'],
+ 'INSTALL': <function copyFunc at 0x700000>,
+ 'INSTALLVERSIONEDLIB': <function copyFuncVersionedLib at 0x700000>,
+ 'LIBPREFIX': 'lib',
+ 'LIBPREFIXES': ['$LIBPREFIX'],
+ 'LIBSUFFIX': '.a',
+ 'LIBSUFFIXES': ['$LIBSUFFIX', '$SHLIBSUFFIX'],
+ 'MAXLINELENGTH': 128072,
+ 'OBJPREFIX': '',
+ 'OBJSUFFIX': '.o',
+ 'PLATFORM': 'posix',
+ 'PROGPREFIX': '',
+ 'PROGSUFFIX': '',
+ 'PSPAWN': <function piped_env_spawn at 0x700000>,
+ 'RDirs': <SCons.Defaults.Variable_Method_Caller object at 0x700000>,
+ 'SCANNERS': [<SCons.Scanner.Base object at 0x700000>],
+ 'SHELL': 'sh',
+ 'SHLIBPREFIX': '$LIBPREFIX',
+ 'SHLIBSUFFIX': '.so',
+ 'SHOBJPREFIX': '$OBJPREFIX',
+ 'SHOBJSUFFIX': '$OBJSUFFIX',
+ 'SPAWN': <function subprocess_spawn at 0x700000>,
+ 'TARGET_ARCH': None,
+ 'TARGET_OS': None,
+ 'TEMPFILE': <class 'SCons.Platform.TempFileMunge'>,
+ 'TEMPFILEPREFIX': '@',
+ 'TOOLS': ['install', 'install'],
+ '_CPPDEFFLAGS': '${_defines(CPPDEFPREFIX, CPPDEFINES, CPPDEFSUFFIX, __env__)}',
+ '_CPPINCFLAGS': '$( ${_concat(INCPREFIX, CPPPATH, INCSUFFIX, __env__, RDirs, TARGET, SOURCE)} $)',
+ '_LIBDIRFLAGS': '$( ${_concat(LIBDIRPREFIX, LIBPATH, LIBDIRSUFFIX, __env__, RDirs, TARGET, SOURCE)} $)',
+ '_LIBFLAGS': '${_concat(LIBLINKPREFIX, LIBS, LIBLINKSUFFIX, __env__)}',
+ '__DRPATH': '$_DRPATH',
+ '__DSHLIBVERSIONFLAGS': '${__libversionflags(__env__,"DSHLIBVERSION","_DSHLIBVERSIONFLAGS")}',
+ '__LDMODULEVERSIONFLAGS': '${__libversionflags(__env__,"LDMODULEVERSION","_LDMODULEVERSIONFLAGS")}',
+ '__RPATH': '$_RPATH',
+ '__SHLIBVERSIONFLAGS': '${__libversionflags(__env__,"SHLIBVERSION","_SHLIBVERSIONFLAGS")}',
+ '__libversionflags': <function __libversionflags at 0x700000>,
+ '_concat': <function _concat at 0x700000>,
+ '_defines': <function _defines at 0x700000>,
+ '_stripixes': <function _stripixes at 0x700000>}
+scons: done reading SConscript files.
+scons: Building targets ...
+scons: `.' is up to date.
+scons: done building targets.
+
+ + On a Windows system with Visual C++ + the output might look like: + +
C:\>scons
+scons: Reading SConscript files ...
+{ 'BUILDERS': {'_InternalInstallVersionedLib': <function InstallVersionedBuilderWrapper at 0x700000>, '_InternalInstall': <function InstallBuilderWrapper at 0x700000>, 'Object': <SCons.Builder.CompositeBuilder object at 0x700000>, 'PCH': <SCons.Builder.BuilderBase object at 0x700000>, 'RES': <SCons.Builder.BuilderBase object at 0x700000>, 'SharedObject': <SCons.Builder.CompositeBuilder object at 0x700000>, 'StaticObject': <SCons.Builder.CompositeBuilder object at 0x700000>, '_InternalInstallAs': <function InstallAsBuilderWrapper at 0x700000>},
+ 'CC': 'cl',
+ 'CCCOM': <SCons.Action.FunctionAction object at 0x700000>,
+ 'CCFLAGS': ['/nologo'],
+ 'CCPCHFLAGS': ['${(PCH and "/Yu%s \\"/Fp%s\\""%(PCHSTOP or "",File(PCH))) or ""}'],
+ 'CCPDBFLAGS': ['${(PDB and "/Z7") or ""}'],
+ 'CFILESUFFIX': '.c',
+ 'CFLAGS': [],
+ 'CONFIGUREDIR': '#/.sconf_temp',
+ 'CONFIGURELOG': '#/config.log',
+ 'CPPDEFPREFIX': '/D',
+ 'CPPDEFSUFFIX': '',
+ 'CPPSUFFIXES': [ '.c',
+ '.C',
+ '.cxx',
+ '.cpp',
+ '.c++',
+ '.cc',
+ '.h',
+ '.H',
+ '.hxx',
+ '.hpp',
+ '.hh',
+ '.F',
+ '.fpp',
+ '.FPP',
+ '.m',
+ '.mm',
+ '.S',
+ '.spp',
+ '.SPP',
+ '.sx'],
+ 'CXX': '$CC',
+ 'CXXCOM': '${TEMPFILE("$CXX $_MSVC_OUTPUT_FLAG /c $CHANGED_SOURCES $CXXFLAGS $CCFLAGS $_CCCOMCOM","$CXXCOMSTR")}',
+ 'CXXFILESUFFIX': '.cc',
+ 'CXXFLAGS': ['$(', '/TP', '$)'],
+ 'DSUFFIXES': ['.d'],
+ 'Dir': <SCons.Defaults.Variable_Method_Caller object at 0x700000>,
+ 'Dirs': <SCons.Defaults.Variable_Method_Caller object at 0x700000>,
+ 'ENV': { 'PATH': 'C:\\WINDOWS\\System32',
+ 'PATHEXT': '.COM;.EXE;.BAT;.CMD',
+ 'SystemRoot': 'C:\\WINDOWS'},
+ 'ESCAPE': <function escape at 0x700000>,
+ 'File': <SCons.Defaults.Variable_Method_Caller object at 0x700000>,
+ 'HOST_ARCH': '',
+ 'HOST_OS': 'win32',
+ 'IDLSUFFIXES': ['.idl', '.IDL'],
+ 'INCPREFIX': '/I',
+ 'INCSUFFIX': '',
+ 'INSTALL': <function copyFunc at 0x700000>,
+ 'INSTALLVERSIONEDLIB': <function copyFuncVersionedLib at 0x700000>,
+ 'LIBPREFIX': '',
+ 'LIBPREFIXES': ['$LIBPREFIX'],
+ 'LIBSUFFIX': '.lib',
+ 'LIBSUFFIXES': ['$LIBSUFFIX'],
+ 'MAXLINELENGTH': 2048,
+ 'MSVC_SETUP_RUN': True,
+ 'OBJPREFIX': '',
+ 'OBJSUFFIX': '.obj',
+ 'PCHCOM': '$CXX /Fo${TARGETS[1]} $CXXFLAGS $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS /c $SOURCES /Yc$PCHSTOP /Fp${TARGETS[0]} $CCPDBFLAGS $PCHPDBFLAGS',
+ 'PCHPDBFLAGS': ['${(PDB and "/Yd") or ""}'],
+ 'PLATFORM': 'win32',
+ 'PROGPREFIX': '',
+ 'PROGSUFFIX': '.exe',
+ 'PSPAWN': <function piped_spawn at 0x700000>,
+ 'RC': 'rc',
+ 'RCCOM': <SCons.Action.FunctionAction object at 0x700000>,
+ 'RCFLAGS': [],
+ 'RCSUFFIXES': ['.rc', '.rc2'],
+ 'RDirs': <SCons.Defaults.Variable_Method_Caller object at 0x700000>,
+ 'SCANNERS': [<SCons.Scanner.Base object at 0x700000>],
+ 'SHCC': '$CC',
+ 'SHCCCOM': <SCons.Action.FunctionAction object at 0x700000>,
+ 'SHCCFLAGS': ['$CCFLAGS'],
+ 'SHCFLAGS': ['$CFLAGS'],
+ 'SHCXX': '$CXX',
+ 'SHCXXCOM': '${TEMPFILE("$SHCXX $_MSVC_OUTPUT_FLAG /c $CHANGED_SOURCES $SHCXXFLAGS $SHCCFLAGS $_CCCOMCOM","$SHCXXCOMSTR")}',
+ 'SHCXXFLAGS': ['$CXXFLAGS'],
+ 'SHELL': None,
+ 'SHLIBPREFIX': '',
+ 'SHLIBSUFFIX': '.dll',
+ 'SHOBJPREFIX': '$OBJPREFIX',
+ 'SHOBJSUFFIX': '$OBJSUFFIX',
+ 'SPAWN': <function spawn at 0x700000>,
+ 'STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME': 1,
+ 'TARGET_ARCH': None,
+ 'TARGET_OS': None,
+ 'TEMPFILE': <class 'SCons.Platform.TempFileMunge'>,
+ 'TEMPFILEPREFIX': '@',
+ 'TOOLS': ['msvc', 'install', 'install'],
+ '_CCCOMCOM': '$CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS $CCPCHFLAGS $CCPDBFLAGS',
+ '_CPPDEFFLAGS': '${_defines(CPPDEFPREFIX, CPPDEFINES, CPPDEFSUFFIX, __env__)}',
+ '_CPPINCFLAGS': '$( ${_concat(INCPREFIX, CPPPATH, INCSUFFIX, __env__, RDirs, TARGET, SOURCE)} $)',
+ '_LIBDIRFLAGS': '$( ${_concat(LIBDIRPREFIX, LIBPATH, LIBDIRSUFFIX, __env__, RDirs, TARGET, SOURCE)} $)',
+ '_LIBFLAGS': '${_concat(LIBLINKPREFIX, LIBS, LIBLINKSUFFIX, __env__)}',
+ '_MSVC_OUTPUT_FLAG': <function msvc_output_flag at 0x700000>,
+ '__DSHLIBVERSIONFLAGS': '${__libversionflags(__env__,"DSHLIBVERSION","_DSHLIBVERSIONFLAGS")}',
+ '__LDMODULEVERSIONFLAGS': '${__libversionflags(__env__,"LDMODULEVERSION","_LDMODULEVERSIONFLAGS")}',
+ '__SHLIBVERSIONFLAGS': '${__libversionflags(__env__,"SHLIBVERSION","_SHLIBVERSIONFLAGS")}',
+ '__libversionflags': <function __libversionflags at 0x700000>,
+ '_concat': <function _concat at 0x700000>,
+ '_defines': <function _defines at 0x700000>,
+ '_stripixes': <function _stripixes at 0x700000>}
+scons: done reading SConscript files.
+scons: Building targets ...
+scons: `.' is up to date.
+scons: done building targets.
+
+ + The construction environments in these examples have + actually been restricted to just gcc and Visual C++, + respectively. + In a real-life situation, + the construction environments will + likely contain a great many more variables. + Also note that we've massaged the example output above + to make the memory address of all objects a constant 0x700000. + In reality, you would see a different hexadecimal + number for each object. + +
+
+ To make it easier to see just what you're
+ interested in,
+ the Dump
method allows you to
+ specify a specific constrcution variable
+ that you want to disply.
+ For example,
+ it's not unusual to want to verify
+ the external environment used to execute build commands,
+ to make sure that the PATH and other
+ environment variables are set up the way they should be.
+ You can do this as follows:
+
+
+env = Environment() +print env.Dump('ENV') +
+ + Which might display the following when executed on a POSIX system: + +
% scons
+scons: Reading SConscript files ...
+{ 'PATH': '/usr/local/bin:/opt/bin:/bin:/usr/bin'}
+scons: done reading SConscript files.
+scons: Building targets ...
+scons: `.' is up to date.
+scons: done building targets.
+
+ + And the following when executed on a Windows system: + +
C:\>scons
+scons: Reading SConscript files ...
+{ 'PATH': 'C:\\WINDOWS\\System32:/usr/bin',
+ 'PATHEXT': '.COM;.EXE;.BAT;.CMD',
+ 'SystemRoot': 'C:\\WINDOWS'}
+scons: done reading SConscript files.
+scons: Building targets ...
+scons: `.' is up to date.
+scons: done building targets.
+
+
+ Sometimes the best way to try to figure out what
+ SCons is doing is simply to take a look at the
+ dependency graph that it constructs
+ based on your SConscript
files.
+ The --tree
option
+ will display all or part of the
+ SCons dependency graph in an
+ "ASCII art" graphical format
+ that shows the dependency hierarchy.
+
+
+
+ For example, given the following input SConstruct
file:
+
+
+env = Environment(CPPPATH = ['.']) +env.Program('prog', ['f1.c', 'f2.c', 'f3.c']) +
+
+ Running SCons with the --tree=all
+ option yields:
+
+
% scons -Q --tree=all
+cc -o f1.o -c -I. f1.c
+cc -o f2.o -c -I. f2.c
+cc -o f3.o -c -I. f3.c
+cc -o prog f1.o f2.o f3.o
++-.
+ +-SConstruct
+ +-f1.c
+ +-f1.o
+ | +-f1.c
+ | +-inc.h
+ +-f2.c
+ +-f2.o
+ | +-f2.c
+ | +-inc.h
+ +-f3.c
+ +-f3.o
+ | +-f3.c
+ | +-inc.h
+ +-inc.h
+ +-prog
+ +-f1.o
+ | +-f1.c
+ | +-inc.h
+ +-f2.o
+ | +-f2.c
+ | +-inc.h
+ +-f3.o
+ +-f3.c
+ +-inc.h
+
+
+ The tree will also be printed when the
+ -n
(no execute) option is used,
+ which allows you to examine the dependency graph
+ for a configuration without actually
+ rebuilding anything in the tree.
+
+
+
+ The --tree
option only prints
+ the dependency graph for the specified targets
+ (or the default target(s) if none are specified on the command line).
+ So if you specify a target like f2.o
+ on the command line,
+ the --tree
option will only
+ print the dependency graph for that file:
+
+
% scons -Q --tree=all f2.o
+cc -o f2.o -c -I. f2.c
++-f2.o
+ +-f2.c
+ +-inc.h
+
+ + This is, of course, useful for + restricting the output from a very large + build configuration to just a + portion in which you're interested. + Multiple targets are fine, + in which case a tree will be printed + for each specified target: + +
% scons -Q --tree=all f1.o f3.o
+cc -o f1.o -c -I. f1.c
++-f1.o
+ +-f1.c
+ +-inc.h
+cc -o f3.o -c -I. f3.c
++-f3.o
+ +-f3.c
+ +-inc.h
+
+
+ The status
argument may be used
+ to tell SCons to print status information about
+ each file in the dependency graph:
+
+
% scons -Q --tree=status
+cc -o f1.o -c -I. f1.c
+cc -o f2.o -c -I. f2.c
+cc -o f3.o -c -I. f3.c
+cc -o prog f1.o f2.o f3.o
+ E = exists
+ R = exists in repository only
+ b = implicit builder
+ B = explicit builder
+ S = side effect
+ P = precious
+ A = always build
+ C = current
+ N = no clean
+ H = no cache
+
+[E b ]+-.
+[E C ] +-SConstruct
+[E C ] +-f1.c
+[E B C ] +-f1.o
+[E C ] | +-f1.c
+[E C ] | +-inc.h
+[E C ] +-f2.c
+[E B C ] +-f2.o
+[E C ] | +-f2.c
+[E C ] | +-inc.h
+[E C ] +-f3.c
+[E B C ] +-f3.o
+[E C ] | +-f3.c
+[E C ] | +-inc.h
+[E C ] +-inc.h
+[E B C ] +-prog
+[E B C ] +-f1.o
+[E C ] | +-f1.c
+[E C ] | +-inc.h
+[E B C ] +-f2.o
+[E C ] | +-f2.c
+[E C ] | +-inc.h
+[E B C ] +-f3.o
+[E C ] +-f3.c
+[E C ] +-inc.h
+
+
+ Note that --tree=all,status
is equivalent;
+ the all
+ is assumed if only status
is present.
+ As an alternative to all
,
+ you can specify --tree=derived
+ to have SCons only print derived targets
+ in the tree output,
+ skipping source files
+ (like .c
and .h
files):
+
+
% scons -Q --tree=derived
+cc -o f1.o -c -I. f1.c
+cc -o f2.o -c -I. f2.c
+cc -o f3.o -c -I. f3.c
+cc -o prog f1.o f2.o f3.o
++-.
+ +-f1.o
+ +-f2.o
+ +-f3.o
+ +-prog
+ +-f1.o
+ +-f2.o
+ +-f3.o
+
+
+ You can use the status
+ modifier with derived
as well:
+
+
% scons -Q --tree=derived,status
+cc -o f1.o -c -I. f1.c
+cc -o f2.o -c -I. f2.c
+cc -o f3.o -c -I. f3.c
+cc -o prog f1.o f2.o f3.o
+ E = exists
+ R = exists in repository only
+ b = implicit builder
+ B = explicit builder
+ S = side effect
+ P = precious
+ A = always build
+ C = current
+ N = no clean
+ H = no cache
+
+[E b ]+-.
+[E B C ] +-f1.o
+[E B C ] +-f2.o
+[E B C ] +-f3.o
+[E B C ] +-prog
+[E B C ] +-f1.o
+[E B C ] +-f2.o
+[E B C ] +-f3.o
+
+
+ Note that the order of the --tree=
+ arguments doesn't matter;
+ --tree=status,derived
is
+ completely equivalent.
+
+
+
+ The default behavior of the --tree
option
+ is to repeat all of the dependencies each time the library dependency
+ (or any other dependency file) is encountered in the tree.
+ If certain target files share other target files,
+ such as two programs that use the same library:
+
+
+env = Environment(CPPPATH = ['.'], + LIBS = ['foo'], + LIBPATH = ['.']) +env.Library('foo', ['f1.c', 'f2.c', 'f3.c']) +env.Program('prog1.c') +env.Program('prog2.c') +
+
+ Then there can be a lot of repetition in the
+ --tree=
output:
+
+
% scons -Q --tree=all
+cc -o f1.o -c -I. f1.c
+cc -o f2.o -c -I. f2.c
+cc -o f3.o -c -I. f3.c
+ar rc libfoo.a f1.o f2.o f3.o
+ranlib libfoo.a
+cc -o prog1.o -c -I. prog1.c
+cc -o prog1 prog1.o -L. -lfoo
+cc -o prog2.o -c -I. prog2.c
+cc -o prog2 prog2.o -L. -lfoo
++-.
+ +-SConstruct
+ +-f1.c
+ +-f1.o
+ | +-f1.c
+ | +-inc.h
+ +-f2.c
+ +-f2.o
+ | +-f2.c
+ | +-inc.h
+ +-f3.c
+ +-f3.o
+ | +-f3.c
+ | +-inc.h
+ +-inc.h
+ +-libfoo.a
+ | +-f1.o
+ | | +-f1.c
+ | | +-inc.h
+ | +-f2.o
+ | | +-f2.c
+ | | +-inc.h
+ | +-f3.o
+ | +-f3.c
+ | +-inc.h
+ +-prog1
+ | +-prog1.o
+ | | +-prog1.c
+ | | +-inc.h
+ | +-libfoo.a
+ | +-f1.o
+ | | +-f1.c
+ | | +-inc.h
+ | +-f2.o
+ | | +-f2.c
+ | | +-inc.h
+ | +-f3.o
+ | +-f3.c
+ | +-inc.h
+ +-prog1.c
+ +-prog1.o
+ | +-prog1.c
+ | +-inc.h
+ +-prog2
+ | +-prog2.o
+ | | +-prog2.c
+ | | +-inc.h
+ | +-libfoo.a
+ | +-f1.o
+ | | +-f1.c
+ | | +-inc.h
+ | +-f2.o
+ | | +-f2.c
+ | | +-inc.h
+ | +-f3.o
+ | +-f3.c
+ | +-inc.h
+ +-prog2.c
+ +-prog2.o
+ +-prog2.c
+ +-inc.h
+
+
+ In a large configuration with many internal libraries
+ and include files,
+ this can very quickly lead to huge output trees.
+ To help make this more manageable,
+ a prune
modifier may
+ be added to the option list,
+ in which case SCons
+ will print the name of a target that has
+ already been visited during the tree-printing
+ in [square brackets]
+ as an indication that the dependencies
+ of the target file may be found
+ by looking farther up the tree:
+
+
% scons -Q --tree=prune
+cc -o f1.o -c -I. f1.c
+cc -o f2.o -c -I. f2.c
+cc -o f3.o -c -I. f3.c
+ar rc libfoo.a f1.o f2.o f3.o
+ranlib libfoo.a
+cc -o prog1.o -c -I. prog1.c
+cc -o prog1 prog1.o -L. -lfoo
+cc -o prog2.o -c -I. prog2.c
+cc -o prog2 prog2.o -L. -lfoo
++-.
+ +-SConstruct
+ +-f1.c
+ +-f1.o
+ | +-f1.c
+ | +-inc.h
+ +-f2.c
+ +-f2.o
+ | +-f2.c
+ | +-inc.h
+ +-f3.c
+ +-f3.o
+ | +-f3.c
+ | +-inc.h
+ +-inc.h
+ +-libfoo.a
+ | +-[f1.o]
+ | +-[f2.o]
+ | +-[f3.o]
+ +-prog1
+ | +-prog1.o
+ | | +-prog1.c
+ | | +-inc.h
+ | +-[libfoo.a]
+ +-prog1.c
+ +-[prog1.o]
+ +-prog2
+ | +-prog2.o
+ | | +-prog2.c
+ | | +-inc.h
+ | +-[libfoo.a]
+ +-prog2.c
+ +-[prog2.o]
+
+
+ Like the status
keyword,
+ the prune
argument by itself
+ is equivalent to --tree=all,prune
.
+
+
+
+ Sometimes it's useful to look at the
+ pre-substitution string
+ that SCons uses to generate
+ the command lines it executes.
+ This can be done with the --debug=presub
option:
+
+
+% scons -Q --debug=presub
+Building prog.o with action:
+ $CC -o $TARGET -c $CFLAGS $CCFLAGS $_CCOMCOM $SOURCES
+cc -o prog.o -c -I. prog.c
+Building prog with action:
+ $SMART_LINKCOM
+cc -o prog prog.o
+
+
+ To get some insight into what library names
+ SCons is searching for,
+ and in which directories it is searching,
+ Use the --debug=findlibs
option.
+ Given the following input SConstruct
file:
+
+
+env = Environment(LIBPATH = ['libs1', 'libs2']) +env.Program('prog.c', LIBS=['foo', 'bar']) +
+
+ And the libraries libfoo.a
+ and libbar.a
+ in libs1
and libs2
,
+ respectively,
+ use of the --debug=findlibs
option yields:
+
+
% scons -Q --debug=findlibs
+ findlibs: looking for 'libfoo.a' in 'libs1' ...
+ findlibs: ... FOUND 'libfoo.a' in 'libs1'
+ findlibs: looking for 'libfoo.so' in 'libs1' ...
+ findlibs: looking for 'libfoo.so' in 'libs2' ...
+ findlibs: looking for 'libbar.a' in 'libs1' ...
+ findlibs: looking for 'libbar.a' in 'libs2' ...
+ findlibs: ... FOUND 'libbar.a' in 'libs2'
+ findlibs: looking for 'libbar.so' in 'libs1' ...
+ findlibs: looking for 'libbar.so' in 'libs2' ...
+cc -o prog.o -c prog.c
+cc -o prog prog.o -Llibs1 -Llibs2 -lfoo -lbar
+
+ + In general, SCons tries to keep its error + messages short and informative. + That means we usually try to avoid showing + the stack traces that are familiar + to experienced Python programmers, + since they usually contain much more + information than is useful to most people. + +
+
+ For example, the following SConstruct
file:
+
+
+Program('prog.c') +
+
+ Generates the following error if the
+ prog.c
file
+ does not exist:
+
+
% scons -Q
+scons: *** [prog.o] Source `prog.c' not found, needed by target `prog.o'.
+
+
+ In this case,
+ the error is pretty obvious.
+ But if it weren't,
+ and you wanted to try to get more information
+ about the error,
+ the --debug=stacktrace
option
+ would show you exactly where in the SCons source code
+ the problem occurs:
+
+
% scons -Q --debug=stacktrace
+scons: *** [prog.o] Source `prog.c' not found, needed by target `prog.o'.
+scons: internal stack trace:
+ File "bootstrap/src/engine/SCons/Job.py", line 199, in start
+ task.prepare()
+ File "bootstrap/src/engine/SCons/Script/Main.py", line 177, in prepare
+ return SCons.Taskmaster.OutOfDateTask.prepare(self)
+ File "bootstrap/src/engine/SCons/Taskmaster.py", line 198, in prepare
+ executor.prepare()
+ File "bootstrap/src/engine/SCons/Executor.py", line 430, in prepare
+ raise SCons.Errors.StopError(msg % (s, self.batches[0].targets[0]))
+
+ + Of course, if you do need to dive into the SCons source code, + we'd like to know if, or how, + the error messages or troubleshooting options + could have been improved to avoid that. + Not everyone has the necessary time or + Python skill to dive into the source code, + and we'd like to improve SCons + for those people as well... + +
+
+ The internal SCons subsystem that handles walking
+ the dependency graph
+ and controls the decision-making about what to rebuild
+ is the Taskmaster
.
+ SCons supports a --taskmastertrace
+ option that tells the Taskmaster to print
+ information about the children (dependencies)
+ of the various Nodes on its walk down the graph,
+ which specific dependent Nodes are being evaluated,
+ and in what order.
+
+
+
+ The --taskmastertrace
option
+ takes as an argument the name of a file in
+ which to put the trace output,
+ with -
(a single hyphen)
+ indicating that the trace messages
+ should be printed to the standard output:
+
+
+env = Environment(CPPPATH = ['.']) +env.Program('prog.c') +
% scons -Q --taskmastertrace=- prog
+
+Taskmaster: Looking for a node to evaluate
+Taskmaster: Considering node <no_state 0 'prog'> and its children:
+Taskmaster: <no_state 0 'prog.o'>
+Taskmaster: adjusted ref count: <pending 1 'prog'>, child 'prog.o'
+Taskmaster: Considering node <no_state 0 'prog.o'> and its children:
+Taskmaster: <no_state 0 'prog.c'>
+Taskmaster: <no_state 0 'inc.h'>
+Taskmaster: adjusted ref count: <pending 1 'prog.o'>, child 'prog.c'
+Taskmaster: adjusted ref count: <pending 2 'prog.o'>, child 'inc.h'
+Taskmaster: Considering node <no_state 0 'prog.c'> and its children:
+Taskmaster: Evaluating <pending 0 'prog.c'>
+
+Task.make_ready_current(): node <pending 0 'prog.c'>
+Task.prepare(): node <up_to_date 0 'prog.c'>
+Task.executed_with_callbacks(): node <up_to_date 0 'prog.c'>
+Task.postprocess(): node <up_to_date 0 'prog.c'>
+Task.postprocess(): removing <up_to_date 0 'prog.c'>
+Task.postprocess(): adjusted parent ref count <pending 1 'prog.o'>
+
+Taskmaster: Looking for a node to evaluate
+Taskmaster: Considering node <no_state 0 'inc.h'> and its children:
+Taskmaster: Evaluating <pending 0 'inc.h'>
+
+Task.make_ready_current(): node <pending 0 'inc.h'>
+Task.prepare(): node <up_to_date 0 'inc.h'>
+Task.executed_with_callbacks(): node <up_to_date 0 'inc.h'>
+Task.postprocess(): node <up_to_date 0 'inc.h'>
+Task.postprocess(): removing <up_to_date 0 'inc.h'>
+Task.postprocess(): adjusted parent ref count <pending 0 'prog.o'>
+
+Taskmaster: Looking for a node to evaluate
+Taskmaster: Considering node <pending 0 'prog.o'> and its children:
+Taskmaster: <up_to_date 0 'prog.c'>
+Taskmaster: <up_to_date 0 'inc.h'>
+Taskmaster: Evaluating <pending 0 'prog.o'>
+
+Task.make_ready_current(): node <pending 0 'prog.o'>
+Task.prepare(): node <executing 0 'prog.o'>
+Task.execute(): node <executing 0 'prog.o'>
+cc -o prog.o -c -I. prog.c
+Task.executed_with_callbacks(): node <executing 0 'prog.o'>
+Task.postprocess(): node <executed 0 'prog.o'>
+Task.postprocess(): removing <executed 0 'prog.o'>
+Task.postprocess(): adjusted parent ref count <pending 0 'prog'>
+
+Taskmaster: Looking for a node to evaluate
+Taskmaster: Considering node <pending 0 'prog'> and its children:
+Taskmaster: <executed 0 'prog.o'>
+Taskmaster: Evaluating <pending 0 'prog'>
+
+Task.make_ready_current(): node <pending 0 'prog'>
+Task.prepare(): node <executing 0 'prog'>
+Task.execute(): node <executing 0 'prog'>
+cc -o prog prog.o
+Task.executed_with_callbacks(): node <executing 0 'prog'>
+Task.postprocess(): node <executed 0 'prog'>
+
+Taskmaster: Looking for a node to evaluate
+Taskmaster: No candidate anymore.
+
+
+ The --taskmastertrace
option
+ doesn't provide information about the actual
+ calculations involved in deciding if a file is up-to-date,
+ but it does show all of the dependencies
+ it knows about for each Node,
+ and the order in which those dependencies are evaluated.
+ This can be useful as an alternate way to determine
+ whether or not your SCons configuration,
+ or the implicit dependency scan,
+ has actually identified all the correct dependencies
+ you want it to.
+
+
+
+ Sometimes SCons doesn't build the target you want
+ and it's difficult to figure out why. You can use
+ the --debug=prepare
option
+ to see all the targets SCons is considering, whether
+ they are already up-to-date or not. The message is
+ printed before SCons decides whether to build the target.
+
+
+ When using the Duplicate
option to create variant dirs,
+ sometimes you may find files not getting copied to where you
+ expect (or not at all), or files mysteriously disappearing. These
+ are usually because of a misconfiguration of some kind in the
+ SConstruct/SConscript, but they can be tricky to debug. The
+ --debug=duplicate option shows each time a variant file is
+ unlinked and relinked from its source (or copied, depending on
+ settings), and also shows a message for removing "stale"
+ variant-dir files that no longer have a corresponding source file.
+ It also prints a line for each target that's removed just before
+ building, since that can also be mistaken for the same thing.
+
+
+ +This appendix contains descriptions of all of the +construction variables that are potentially +available "out of the box" in this version of SCons. +Whether or not setting a construction variable +in a construction environment +will actually have an effect depends on +whether any of the Tools and/or Builders +that use the variable have been +included in the construction environment. + +
+
+In this appendix, we have
+appended the initial $
+(dollar sign) to the beginning of each
+variable name when it appears in the text,
+but left off the dollar sign
+in the left-hand column
+where the name appears for each entry.
+
+
+This construction variable automatically introduces $_LDMODULEVERSIONFLAGS
+if $LDMODULEVERSION
is set. Othervise it evaluates to an empty string.
+
+This construction variable automatically introduces $_SHLIBVERSIONFLAGS
+if $SHLIBVERSION
is set. Othervise it evaluates to an empty string.
+
+ A macro (by default a generator function) used to create the linker flags to specify
+ apple's linker's -compatibility_version flag.
+ The default generator uses $APPLELINK_COMPATIBILITY_VERSION
+ and $APPLELINK_NO_COMPATIBILITY_VERSION
and $SHLIBVERSION
+ to determine the correct flag.
+
+ On Mac OS X this is used to set the linker flag: + + -compatibility_version +
+ The value is specified as X[.Y[.Z]] where X is between 1 and 65535, Y can be omitted or between 1 and
+ 255, Z can be omitted or between 1 and 255. This value will be derived from $SHLIBVERSION
if
+ not
+ specified. The lowest digit will be dropped and replaced by a 0.
+
+ If the $APPLELINK_NO_COMPATIBILITY_VERSION
is set then no -compatibility_version will be
+ output.
+
See MacOS's ld manpage for more details
+ A macro (by default a generator function) used to create the linker flags to specify apple's linker's
+ -current_version flag. The default generator uses $APPLELINK_CURRENT_VERSION
and
+ $APPLELINK_NO_CURRENT_VERSION
and $SHLIBVERSION
to determine the correct flag.
+
+ On Mac OS X this is used to set the linker flag: + + -current_version +
+ The value is specified as X[.Y[.Z]] where X is between 1 and 65535, Y can be omitted or between 1 and
+ 255, Z can be omitted or between 1 and 255. This value will be set to $SHLIBVERSION
if not
+ specified.
+
+ If the $APPLELINK_NO_CURRENT_VERSION
is set then no -current_version will be
+ output.
+
See MacOS's ld manpage for more details
+ Set this to any True (1|True|non-empty string) value to disable adding -compatibility_version flag when + generating versioned shared libraries. +
+ This overrides $APPLELINK_COMPATIBILITY_VERSION
.
+
+ Set this to any True (1|True|non-empty string) value to disable adding -current_version flag when + generating versioned shared libraries. +
+ This overrides $APPLELINK_CURRENT_VERSION
.
+
+The static library archiver. +
+Specifies the system architecture for which
+the package is being built.
+The default is the system architecture
+of the machine on which SCons is running.
+This is used to fill in the
+Architecture:
+field in an Ipkg
+control
file,
+and the BuildArch:
field
+in the RPM .spec
file,
+as well as forming part of the name of a generated RPM package file.
+
+The command line used to generate a static library from object files. +
+The string displayed when an object file
+is generated from an assembly-language source file.
+If this is not set, then $ARCOM
(the command line) is displayed.
+
+env = Environment(ARCOMSTR = "Archiving $TARGET") +
+General options passed to the static library archiver. +
+The assembler. +
+The command line used to generate an object file +from an assembly-language source file. +
+The string displayed when an object file
+is generated from an assembly-language source file.
+If this is not set, then $ASCOM
(the command line) is displayed.
+
+env = Environment(ASCOMSTR = "Assembling $TARGET") +
+General options passed to the assembler. +
+The command line used to assemble an assembly-language
+source file into an object file
+after first running the file through the C preprocessor.
+Any options specified
+in the $ASFLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+
+The string displayed when an object file
+is generated from an assembly-language source file
+after first running the file through the C preprocessor.
+If this is not set, then $ASPPCOM
(the command line) is displayed.
+
+env = Environment(ASPPCOMSTR = "Assembling $TARGET") +
+General options when an assembling an assembly-language
+source file into an object file
+after first running the file through the C preprocessor.
+The default is to use the value of $ASFLAGS
.
+
+The bibliography generator for the TeX formatter and typesetter and the +LaTeX structured formatter and typesetter. +
+The command line used to call the bibliography generator for the +TeX formatter and typesetter and the LaTeX structured formatter and +typesetter. +
+The string displayed when generating a bibliography
+for TeX or LaTeX.
+If this is not set, then $BIBTEXCOM
(the command line) is displayed.
+
+env = Environment(BIBTEXCOMSTR = "Generating bibliography $TARGET") +
+General options passed to the bibliography generator for the TeX formatter +and typesetter and the LaTeX structured formatter and typesetter. +
+A dictionary mapping the names of the builders +available through this environment +to underlying Builder objects. +Builders named +Alias, CFile, CXXFile, DVI, Library, Object, PDF, PostScript, and Program +are available by default. +If you initialize this variable when an +Environment is created: +
+env = Environment(BUILDERS = {'NewBuilder' : foo}) +
+the default Builders will no longer be available. +To use a new Builder object in addition to the default Builders, +add your new Builder object like this: +
+env = Environment() +env.Append(BUILDERS = {'NewBuilder' : foo}) +
+or this: +
+env = Environment() +env['BUILDERS']['NewBuilder'] = foo +
+The C compiler. +
+The command line used to compile a C source file to a (static) object
+file. Any options specified in the $CFLAGS
, $CCFLAGS
and
+$CPPFLAGS
construction variables are included on this command
+line.
+
+The string displayed when a C source file
+is compiled to a (static) object file.
+If this is not set, then $CCCOM
(the command line) is displayed.
+
+env = Environment(CCCOMSTR = "Compiling static object $TARGET") +
+General options that are passed to the C and C++ compilers. +
+Options added to the compiler command line
+to support building with precompiled headers.
+The default value expands expands to the appropriate
+Microsoft Visual C++ command-line options
+when the $PCH
construction variable is set.
+
+Options added to the compiler command line
+to support storing debugging information in a
+Microsoft Visual C++ PDB file.
+The default value expands expands to appropriate
+Microsoft Visual C++ command-line options
+when the $PDB
construction variable is set.
+
+The Visual C++ compiler option that SCons uses by default
+to generate PDB information is /Z7
.
+This works correctly with parallel (-j
) builds
+because it embeds the debug information in the intermediate object files,
+as opposed to sharing a single PDB file between multiple object files.
+This is also the only way to get debug information
+embedded into a static library.
+Using the /Zi
instead may yield improved
+link-time performance,
+although parallel builds will no longer work.
+
+You can generate PDB files with the /Zi
+switch by overriding the default $CCPDBFLAGS
variable as follows:
+
+env['CCPDBFLAGS'] = ['${(PDB and "/Zi /Fd%s" % File(PDB)) or ""}'] +
+An alternative would be to use the /Zi
+to put the debugging information in a separate .pdb
+file for each object file by overriding
+the $CCPDBFLAGS
variable as follows:
+
+env['CCPDBFLAGS'] = '/Zi /Fd${TARGET}.pdb' +
+The version number of the C compiler. +This may or may not be set, +depending on the specific C compiler being used. +
+The suffix for C source files.
+This is used by the internal CFile builder
+when generating C files from Lex (.l) or YACC (.y) input files.
+The default suffix, of course, is
+.c
+(lower case).
+On case-insensitive systems (like Windows),
+SCons also treats
+.C
+(upper case) files
+as C files.
+
+General options that are passed to the C compiler (C only; not C++). +
+A hook for modifying the file that controls the packaging build
+(the .spec
for RPM,
+the control
for Ipkg,
+the .wxs
for MSI).
+If set, the function will be called
+after the SCons template for the file has been written.
+
+A reserved variable name +that may not be set or used in a construction environment. +(See "Variable Substitution," below.) +
+A reserved variable name +that may not be set or used in a construction environment. +(See "Variable Substitution," below.) +
+The name of a file containing the change log text
+to be included in the package.
+This is included as the
+%changelog
+section of the RPM
+.spec
file.
+
+A function used to produce variables like $_CPPINCFLAGS
. It takes
+four or five
+arguments: a prefix to concatenate onto each element, a list of
+elements, a suffix to concatenate onto each element, an environment
+for variable interpolation, and an optional function that will be
+called to transform the list before concatenation.
+
+env['_CPPINCFLAGS'] = '$( ${_concat(INCPREFIX, CPPPATH, INCSUFFIX, __env__, RDirs)} $)', +
+The name of the directory in which
+Configure context test files are written.
+The default is
+.sconf_temp
+in the top-level directory
+containing the
+SConstruct
+file.
+
+The name of the Configure context log file.
+The default is
+config.log
+in the top-level directory
+containing the
+SConstruct
+file.
+
+An automatically-generated construction variable
+containing the C preprocessor command-line options
+to define values.
+The value of $_CPPDEFFLAGS
is created
+by respectively prepending and appending
+$CPPDEFPREFIX
and $CPPDEFSUFFIX
+to the beginning and end
+of each definition in $CPPDEFINES
.
+
+A platform independent specification of C preprocessor definitions.
+The definitions will be added to command lines
+through the automatically-generated
+$_CPPDEFFLAGS
construction variable (see above),
+which is constructed according to
+the type of value of $CPPDEFINES
:
+
+If $CPPDEFINES
is a string,
+the values of the
+$CPPDEFPREFIX
and $CPPDEFSUFFIX
+construction variables
+will be respectively prepended and appended to the beginning and end
+of each definition in $CPPDEFINES
.
+
+# Will add -Dxyz to POSIX compiler command lines, +# and /Dxyz to Microsoft Visual C++ command lines. +env = Environment(CPPDEFINES='xyz') +
+If $CPPDEFINES
is a list,
+the values of the
+$CPPDEFPREFIX
and $CPPDEFSUFFIX
+construction variables
+will be respectively prepended and appended to the beginning and end
+of each element in the list.
+If any element is a list or tuple,
+then the first item is the name being
+defined and the second item is its value:
+
+# Will add -DB=2 -DA to POSIX compiler command lines, +# and /DB=2 /DA to Microsoft Visual C++ command lines. +env = Environment(CPPDEFINES=[('B', 2), 'A']) +
+If $CPPDEFINES
is a dictionary,
+the values of the
+$CPPDEFPREFIX
and $CPPDEFSUFFIX
+construction variables
+will be respectively prepended and appended to the beginning and end
+of each item from the dictionary.
+The key of each dictionary item
+is a name being defined
+to the dictionary item's corresponding value;
+if the value is
+None
,
+then the name is defined without an explicit value.
+Note that the resulting flags are sorted by keyword
+to ensure that the order of the options on the
+command line is consistent each time
+scons
+is run.
+
+# Will add -DA -DB=2 to POSIX compiler command lines, +# and /DA /DB=2 to Microsoft Visual C++ command lines. +env = Environment(CPPDEFINES={'B':2, 'A':None}) +
+The prefix used to specify preprocessor definitions
+on the C compiler command line.
+This will be prepended to the beginning of each definition
+in the $CPPDEFINES
construction variable
+when the $_CPPDEFFLAGS
variable is automatically generated.
+
+The suffix used to specify preprocessor definitions
+on the C compiler command line.
+This will be appended to the end of each definition
+in the $CPPDEFINES
construction variable
+when the $_CPPDEFFLAGS
variable is automatically generated.
+
+User-specified C preprocessor options.
+These will be included in any command that uses the C preprocessor,
+including not just compilation of C and C++ source files
+via the $CCCOM
,
+$SHCCCOM
,
+$CXXCOM
and
+$SHCXXCOM
command lines,
+but also the $FORTRANPPCOM
,
+$SHFORTRANPPCOM
,
+$F77PPCOM
and
+$SHF77PPCOM
command lines
+used to compile a Fortran source file,
+and the $ASPPCOM
command line
+used to assemble an assembly language source file,
+after first running each file through the C preprocessor.
+Note that this variable does
+not
+contain
+-I
+(or similar) include search path options
+that scons generates automatically from $CPPPATH
.
+See $_CPPINCFLAGS
, below,
+for the variable that expands to those options.
+
+An automatically-generated construction variable
+containing the C preprocessor command-line options
+for specifying directories to be searched for include files.
+The value of $_CPPINCFLAGS
is created
+by respectively prepending and appending $INCPREFIX
and $INCSUFFIX
+to the beginning and end
+of each directory in $CPPPATH
.
+
+The list of directories that the C preprocessor will search for include
+directories. The C/C++ implicit dependency scanner will search these
+directories for include files. Don't explicitly put include directory
+arguments in CCFLAGS or CXXFLAGS because the result will be non-portable
+and the directories will not be searched by the dependency scanner. Note:
+directory names in CPPPATH will be looked-up relative to the SConscript
+directory when they are used in a command. To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+
+env = Environment(CPPPATH='#/include') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+include = Dir('include') +env = Environment(CPPPATH=include) +
+The directory list will be added to command lines
+through the automatically-generated
+$_CPPINCFLAGS
+construction variable,
+which is constructed by
+respectively prepending and appending the value of the
+$INCPREFIX
and $INCSUFFIX
+construction variables
+to the beginning and end
+of each directory in $CPPPATH
.
+Any command lines you define that need
+the CPPPATH directory list should
+include $_CPPINCFLAGS
:
+
+env = Environment(CCCOM="my_compiler $_CPPINCFLAGS -c -o $TARGET $SOURCE") +
+The list of suffixes of files that will be scanned +for C preprocessor implicit dependencies +(#include lines). +The default list is: +
+[".c", ".C", ".cxx", ".cpp", ".c++", ".cc", + ".h", ".H", ".hxx", ".hpp", ".hh", + ".F", ".fpp", ".FPP", + ".m", ".mm", + ".S", ".spp", ".SPP"] +
+The C++ compiler. +
+The command line used to compile a C++ source file to an object file.
+Any options specified in the $CXXFLAGS
and
+$CPPFLAGS
construction variables
+are included on this command line.
+
+The string displayed when a C++ source file
+is compiled to a (static) object file.
+If this is not set, then $CXXCOM
(the command line) is displayed.
+
+env = Environment(CXXCOMSTR = "Compiling static object $TARGET") +
+The suffix for C++ source files.
+This is used by the internal CXXFile builder
+when generating C++ files from Lex (.ll) or YACC (.yy) input files.
+The default suffix is
+.cc
.
+SCons also treats files with the suffixes
+.cpp
,
+.cxx
,
+.c++
,
+and
+.C++
+as C++ files,
+and files with
+.mm
+suffixes as Objective C++ files.
+On case-sensitive systems (Linux, UNIX, and other POSIX-alikes),
+SCons also treats
+.C
+(upper case) files
+as C++ files.
+
+General options that are passed to the C++ compiler.
+By default, this includes the value of $CCFLAGS
,
+so that setting $CCFLAGS
affects both C and C++ compilation.
+If you want to add C++-specific flags,
+you must set or override the value of $CXXFLAGS
.
+
+The version number of the C++ compiler. +This may or may not be set, +depending on the specific C++ compiler being used. +
+The D compiler to use. +
+The D compiler to use. +
+The D compiler to use. +
+ The command line used to compile a D file to an object file.
+ Any options specified in the $DFLAGS
construction variable
+ is included on this command line.
+
+ The command line used to compile a D file to an object file.
+ Any options specified in the $DFLAGS
construction variable
+ is included on this command line.
+
+ The command line used to compile a D file to an object file.
+ Any options specified in the $DFLAGS
construction variable
+ is included on this command line.
+
+ List of debug tags to enable when compiling. +
+ List of debug tags to enable when compiling. +
+ List of debug tags to enable when compiling. +
+ DDEBUGPREFIX. +
+ DDEBUGPREFIX. +
+ DDEBUGPREFIX. +
+ DDEBUGSUFFIX. +
+ DDEBUGSUFFIX. +
+ DDEBUGSUFFIX. +
+A long description of the project being packaged. +This is included in the relevant section +of the file that controls the packaging build. +
+A language-specific long description for
+the specified lang
.
+This is used to populate a
+%description -l
+section of an RPM
+.spec
file.
+
+ DFILESUFFIX. +
+ DFILESUFFIX. +
+ DFILESUFFIX. +
+ DFLAGPREFIX. +
+ DFLAGPREFIX. +
+ DFLAGPREFIX. +
+ General options that are passed to the D compiler. +
+ General options that are passed to the D compiler. +
+ General options that are passed to the D compiler. +
+ DFLAGSUFFIX. +
+ DFLAGSUFFIX. +
+ DFLAGSUFFIX. +
+ DINCPREFIX. +
+ DINCPREFIX. +
+ DINCPREFIX. +
+ DLIBFLAGSUFFIX. +
+ DLIBFLAGSUFFIX. +
+ DLIBFLAGSUFFIX. +
+A function that converts a string +into a Dir instance relative to the target being built. +
+A function that converts a string +into a Dir instance relative to the target being built. +
+A function that converts a list of strings +into a list of Dir instances relative to the target being built. +
+ Name of the lib tool to use for D codes. +
+ Name of the lib tool to use for D codes. +
+ Name of the lib tool to use for D codes. +
+ The command line to use when creating libraries. +
+ The command line to use when creating libraries. +
+ The command line to use when creating libraries. +
+ DLIBLINKPREFIX. +
+ DLIBLINKPREFIX. +
+ DLIBLINKPREFIX. +
+ DLIBLINKSUFFIX. +
+ DLIBLINKSUFFIX. +
+ DLIBLINKSUFFIX. +
+ DLIBFLAGPREFIX. +
+ DLIBFLAGPREFIX. +
+ DLIBFLAGPREFIX. +
+ DLIBFLAGSUFFIX. +
+ DLIBFLAGSUFFIX. +
+ DLIBFLAGSUFFIX. +
+ DLIBLINKPREFIX. +
+ DLIBLINKPREFIX. +
+ DLIBLINKPREFIX. +
+ DLIBLINKSUFFIX. +
+ DLIBLINKSUFFIX. +
+ DLIBLINKSUFFIX. +
+ Name of the linker to use for linking systems including D sources. +
+ Name of the linker to use for linking systems including D sources. +
+ Name of the linker to use for linking systems including D sources. +
+ The command line to use when linking systems including D sources. +
+ The command line to use when linking systems including D sources. +
+ The command line to use when linking systems including D sources. +
+ DLINKFLAGPREFIX. +
+ DLINKFLAGPREFIX. +
+ DLINKFLAGPREFIX. +
+List of linker flags. +
+List of linker flags. +
+List of linker flags. +
+ DLINKFLAGSUFFIX. +
+ DLINKFLAGSUFFIX. +
+ DLINKFLAGSUFFIX. +
+The default XSLT file for the DocbookEpub
builder within the
+current environment, if no other XSLT gets specified via keyword.
+
+The default XSLT file for the DocbookHtml
builder within the
+current environment, if no other XSLT gets specified via keyword.
+
+The default XSLT file for the DocbookHtmlChunked
builder within the
+current environment, if no other XSLT gets specified via keyword.
+
+The default XSLT file for the DocbookHtmlhelp
builder within the
+current environment, if no other XSLT gets specified via keyword.
+
+The default XSLT file for the DocbookMan
builder within the
+current environment, if no other XSLT gets specified via keyword.
+
+The default XSLT file for the DocbookPdf
builder within the
+current environment, if no other XSLT gets specified via keyword.
+
+The default XSLT file for the DocbookSlidesHtml
builder within the
+current environment, if no other XSLT gets specified via keyword.
+
+The default XSLT file for the DocbookSlidesPdf
builder within the
+current environment, if no other XSLT gets specified via keyword.
+
+The path to the PDF renderer fop
or xep
,
+if one of them is installed (fop
gets checked first).
+
+The full command-line for the
+PDF renderer fop
or xep
.
+
+The string displayed when a renderer like fop
or
+xep
is used to create PDF output from an XML file.
+
+Additonal command-line flags for the
+PDF renderer fop
or xep
.
+
+The path to the external executable xmllint
, if it's installed.
+Note, that this is only used as last fallback for resolving
+XIncludes, if no libxml2 or lxml Python binding can be imported
+in the current system.
+
+The full command-line for the external executable
+xmllint
.
+
+The string displayed when xmllint
is used to resolve
+XIncludes for a given XML file.
+
+Additonal command-line flags for the external executable
+xmllint
.
+
+The path to the external executable xsltproc
+(or saxon
, xalan
), if one of them
+is installed.
+Note, that this is only used as last fallback for XSL transformations, if
+no libxml2 or lxml Python binding can be imported in the current system.
+
+The full command-line for the external executable
+xsltproc
(or saxon
,
+xalan
).
+
+The string displayed when xsltproc
is used to transform
+an XML file via a given XSLT stylesheet.
+
+Additonal command-line flags for the external executable
+xsltproc
(or saxon
,
+xalan
).
+
+Additonal parameters that are not intended for the XSLT processor executable, but
+the XSL processing itself. By default, they get appended at the end of the command line
+for saxon
and saxon-xslt
, respectively.
+
+ List of paths to search for import modules. +
+ List of paths to search for import modules. +
+ List of paths to search for import modules. +
+ DRPATHPREFIX. +
+ DRPATHSUFFIX. +
+ DShLibSonameGenerator. +
+The list of suffixes of files that will be scanned +for imported D package files. +The default list is: +
+['.d'] +
+ DVERPREFIX. +
+ DVERPREFIX. +
+ DVERPREFIX. +
+ List of version tags to enable when compiling. +
+ List of version tags to enable when compiling. +
+ List of version tags to enable when compiling. +
+ DVERSUFFIX. +
+ DVERSUFFIX. +
+ DVERSUFFIX. +
+The TeX DVI file to PDF file converter. +
+The command line used to convert TeX DVI files into a PDF file. +
+The string displayed when a TeX DVI file
+is converted into a PDF file.
+If this is not set, then $DVIPDFCOM
(the command line) is displayed.
+
+General options passed to the TeX DVI file to PDF file converter. +
+The TeX DVI file to PostScript converter. +
+General options passed to the TeX DVI file to PostScript converter. +
+A dictionary of environment variables
+to use when invoking commands. When
+$ENV
is used in a command all list
+values will be joined using the path separator and any other non-string
+values will simply be coerced to a string.
+Note that, by default,
+scons
+does
+not
+propagate the environment in force when you
+execute
+scons
+to the commands used to build target files.
+This is so that builds will be guaranteed
+repeatable regardless of the environment
+variables set at the time
+scons
+is invoked.
+
+If you want to propagate your +environment variables +to the commands executed +to build target files, +you must do so explicitly: +
+import os +env = Environment(ENV = os.environ) +
+Note that you can choose only to propagate
+certain environment variables.
+A common example is
+the system
+PATH
+environment variable,
+so that
+scons
+uses the same utilities
+as the invoking shell (or other process):
+
+import os +env = Environment(ENV = {'PATH' : os.environ['PATH']}) +
+A function that will be called to escape shell special characters in +command lines. The function should take one argument: the command line +string to escape; and should return the escaped command line. +
+The Fortran 03 compiler.
+You should normally set the $FORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $F03
if you need to use a specific compiler
+or compiler version for Fortran 03 files.
+
+The command line used to compile a Fortran 03 source file to an object file.
+You only need to set $F03COM
if you need to use a specific
+command line for Fortran 03 files.
+You should normally set the $FORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 03 source file
+is compiled to an object file.
+If this is not set, then $F03COM
or $FORTRANCOM
+(the command line) is displayed.
+
+The list of file extensions for which the F03 dialect will be used. By +default, this is ['.f03'] +
+General user-specified options that are passed to the Fortran 03 compiler.
+Note that this variable does
+not
+contain
+-I
+(or similar) include search path options
+that scons generates automatically from $F03PATH
.
+See
+$_F03INCFLAGS
+below,
+for the variable that expands to those options.
+You only need to set $F03FLAGS
if you need to define specific
+user options for Fortran 03 files.
+You should normally set the $FORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+An automatically-generated construction variable
+containing the Fortran 03 compiler command-line options
+for specifying directories to be searched for include files.
+The value of $_F03INCFLAGS
is created
+by appending $INCPREFIX
and $INCSUFFIX
+to the beginning and end
+of each directory in $F03PATH
.
+
+The list of directories that the Fortran 03 compiler will search for include
+directories. The implicit dependency scanner will search these
+directories for include files. Don't explicitly put include directory
+arguments in $F03FLAGS
because the result will be non-portable
+and the directories will not be searched by the dependency scanner. Note:
+directory names in $F03PATH
will be looked-up relative to the SConscript
+directory when they are used in a command. To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+You only need to set $F03PATH
if you need to define a specific
+include path for Fortran 03 files.
+You should normally set the $FORTRANPATH
variable,
+which specifies the include path
+for the default Fortran compiler
+for all Fortran versions.
+
+env = Environment(F03PATH='#/include') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+include = Dir('include') +env = Environment(F03PATH=include) +
+The directory list will be added to command lines
+through the automatically-generated
+$_F03INCFLAGS
+construction variable,
+which is constructed by
+appending the values of the
+$INCPREFIX
and $INCSUFFIX
+construction variables
+to the beginning and end
+of each directory in $F03PATH
.
+Any command lines you define that need
+the F03PATH directory list should
+include $_F03INCFLAGS
:
+
+env = Environment(F03COM="my_compiler $_F03INCFLAGS -c -o $TARGET $SOURCE") +
+The command line used to compile a Fortran 03 source file to an object file
+after first running the file through the C preprocessor.
+Any options specified in the $F03FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $F03PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 03 files.
+You should normally set the $FORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 03 source file
+is compiled to an object file
+after first running the file through the C preprocessor.
+If this is not set, then $F03PPCOM
or $FORTRANPPCOM
+(the command line) is displayed.
+
+The list of file extensions for which the compilation + preprocessor pass for +F03 dialect will be used. By default, this is empty +
+The Fortran 08 compiler.
+You should normally set the $FORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $F08
if you need to use a specific compiler
+or compiler version for Fortran 08 files.
+
+The command line used to compile a Fortran 08 source file to an object file.
+You only need to set $F08COM
if you need to use a specific
+command line for Fortran 08 files.
+You should normally set the $FORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 08 source file
+is compiled to an object file.
+If this is not set, then $F08COM
or $FORTRANCOM
+(the command line) is displayed.
+
+The list of file extensions for which the F08 dialect will be used. By +default, this is ['.f08'] +
+General user-specified options that are passed to the Fortran 08 compiler.
+Note that this variable does
+not
+contain
+-I
+(or similar) include search path options
+that scons generates automatically from $F08PATH
.
+See
+$_F08INCFLAGS
+below,
+for the variable that expands to those options.
+You only need to set $F08FLAGS
if you need to define specific
+user options for Fortran 08 files.
+You should normally set the $FORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+An automatically-generated construction variable
+containing the Fortran 08 compiler command-line options
+for specifying directories to be searched for include files.
+The value of $_F08INCFLAGS
is created
+by appending $INCPREFIX
and $INCSUFFIX
+to the beginning and end
+of each directory in $F08PATH
.
+
+The list of directories that the Fortran 08 compiler will search for include
+directories. The implicit dependency scanner will search these
+directories for include files. Don't explicitly put include directory
+arguments in $F08FLAGS
because the result will be non-portable
+and the directories will not be searched by the dependency scanner. Note:
+directory names in $F08PATH
will be looked-up relative to the SConscript
+directory when they are used in a command. To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+You only need to set $F08PATH
if you need to define a specific
+include path for Fortran 08 files.
+You should normally set the $FORTRANPATH
variable,
+which specifies the include path
+for the default Fortran compiler
+for all Fortran versions.
+
+env = Environment(F08PATH='#/include') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+include = Dir('include') +env = Environment(F08PATH=include) +
+The directory list will be added to command lines
+through the automatically-generated
+$_F08INCFLAGS
+construction variable,
+which is constructed by
+appending the values of the
+$INCPREFIX
and $INCSUFFIX
+construction variables
+to the beginning and end
+of each directory in $F08PATH
.
+Any command lines you define that need
+the F08PATH directory list should
+include $_F08INCFLAGS
:
+
+env = Environment(F08COM="my_compiler $_F08INCFLAGS -c -o $TARGET $SOURCE") +
+The command line used to compile a Fortran 08 source file to an object file
+after first running the file through the C preprocessor.
+Any options specified in the $F08FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $F08PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 08 files.
+You should normally set the $FORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 08 source file
+is compiled to an object file
+after first running the file through the C preprocessor.
+If this is not set, then $F08PPCOM
or $FORTRANPPCOM
+(the command line) is displayed.
+
+The list of file extensions for which the compilation + preprocessor pass for +F08 dialect will be used. By default, this is empty +
+The Fortran 77 compiler.
+You should normally set the $FORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $F77
if you need to use a specific compiler
+or compiler version for Fortran 77 files.
+
+The command line used to compile a Fortran 77 source file to an object file.
+You only need to set $F77COM
if you need to use a specific
+command line for Fortran 77 files.
+You should normally set the $FORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 77 source file
+is compiled to an object file.
+If this is not set, then $F77COM
or $FORTRANCOM
+(the command line) is displayed.
+
+The list of file extensions for which the F77 dialect will be used. By +default, this is ['.f77'] +
+General user-specified options that are passed to the Fortran 77 compiler.
+Note that this variable does
+not
+contain
+-I
+(or similar) include search path options
+that scons generates automatically from $F77PATH
.
+See
+$_F77INCFLAGS
+below,
+for the variable that expands to those options.
+You only need to set $F77FLAGS
if you need to define specific
+user options for Fortran 77 files.
+You should normally set the $FORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+An automatically-generated construction variable
+containing the Fortran 77 compiler command-line options
+for specifying directories to be searched for include files.
+The value of $_F77INCFLAGS
is created
+by appending $INCPREFIX
and $INCSUFFIX
+to the beginning and end
+of each directory in $F77PATH
.
+
+The list of directories that the Fortran 77 compiler will search for include
+directories. The implicit dependency scanner will search these
+directories for include files. Don't explicitly put include directory
+arguments in $F77FLAGS
because the result will be non-portable
+and the directories will not be searched by the dependency scanner. Note:
+directory names in $F77PATH
will be looked-up relative to the SConscript
+directory when they are used in a command. To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+You only need to set $F77PATH
if you need to define a specific
+include path for Fortran 77 files.
+You should normally set the $FORTRANPATH
variable,
+which specifies the include path
+for the default Fortran compiler
+for all Fortran versions.
+
+env = Environment(F77PATH='#/include') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+include = Dir('include') +env = Environment(F77PATH=include) +
+The directory list will be added to command lines
+through the automatically-generated
+$_F77INCFLAGS
+construction variable,
+which is constructed by
+appending the values of the
+$INCPREFIX
and $INCSUFFIX
+construction variables
+to the beginning and end
+of each directory in $F77PATH
.
+Any command lines you define that need
+the F77PATH directory list should
+include $_F77INCFLAGS
:
+
+env = Environment(F77COM="my_compiler $_F77INCFLAGS -c -o $TARGET $SOURCE") +
+The command line used to compile a Fortran 77 source file to an object file
+after first running the file through the C preprocessor.
+Any options specified in the $F77FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $F77PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 77 files.
+You should normally set the $FORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 77 source file
+is compiled to an object file
+after first running the file through the C preprocessor.
+If this is not set, then $F77PPCOM
or $FORTRANPPCOM
+(the command line) is displayed.
+
+The list of file extensions for which the compilation + preprocessor pass for +F77 dialect will be used. By default, this is empty +
+The Fortran 90 compiler.
+You should normally set the $FORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $F90
if you need to use a specific compiler
+or compiler version for Fortran 90 files.
+
+The command line used to compile a Fortran 90 source file to an object file.
+You only need to set $F90COM
if you need to use a specific
+command line for Fortran 90 files.
+You should normally set the $FORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 90 source file
+is compiled to an object file.
+If this is not set, then $F90COM
or $FORTRANCOM
+(the command line) is displayed.
+
+The list of file extensions for which the F90 dialect will be used. By +default, this is ['.f90'] +
+General user-specified options that are passed to the Fortran 90 compiler.
+Note that this variable does
+not
+contain
+-I
+(or similar) include search path options
+that scons generates automatically from $F90PATH
.
+See
+$_F90INCFLAGS
+below,
+for the variable that expands to those options.
+You only need to set $F90FLAGS
if you need to define specific
+user options for Fortran 90 files.
+You should normally set the $FORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+An automatically-generated construction variable
+containing the Fortran 90 compiler command-line options
+for specifying directories to be searched for include files.
+The value of $_F90INCFLAGS
is created
+by appending $INCPREFIX
and $INCSUFFIX
+to the beginning and end
+of each directory in $F90PATH
.
+
+The list of directories that the Fortran 90 compiler will search for include
+directories. The implicit dependency scanner will search these
+directories for include files. Don't explicitly put include directory
+arguments in $F90FLAGS
because the result will be non-portable
+and the directories will not be searched by the dependency scanner. Note:
+directory names in $F90PATH
will be looked-up relative to the SConscript
+directory when they are used in a command. To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+You only need to set $F90PATH
if you need to define a specific
+include path for Fortran 90 files.
+You should normally set the $FORTRANPATH
variable,
+which specifies the include path
+for the default Fortran compiler
+for all Fortran versions.
+
+env = Environment(F90PATH='#/include') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+include = Dir('include') +env = Environment(F90PATH=include) +
+The directory list will be added to command lines
+through the automatically-generated
+$_F90INCFLAGS
+construction variable,
+which is constructed by
+appending the values of the
+$INCPREFIX
and $INCSUFFIX
+construction variables
+to the beginning and end
+of each directory in $F90PATH
.
+Any command lines you define that need
+the F90PATH directory list should
+include $_F90INCFLAGS
:
+
+env = Environment(F90COM="my_compiler $_F90INCFLAGS -c -o $TARGET $SOURCE") +
+The command line used to compile a Fortran 90 source file to an object file
+after first running the file through the C preprocessor.
+Any options specified in the $F90FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $F90PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 90 files.
+You should normally set the $FORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 90 source file
+is compiled after first running the file through the C preprocessor.
+If this is not set, then $F90PPCOM
or $FORTRANPPCOM
+(the command line) is displayed.
+
+The list of file extensions for which the compilation + preprocessor pass for +F90 dialect will be used. By default, this is empty +
+The Fortran 95 compiler.
+You should normally set the $FORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $F95
if you need to use a specific compiler
+or compiler version for Fortran 95 files.
+
+The command line used to compile a Fortran 95 source file to an object file.
+You only need to set $F95COM
if you need to use a specific
+command line for Fortran 95 files.
+You should normally set the $FORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 95 source file
+is compiled to an object file.
+If this is not set, then $F95COM
or $FORTRANCOM
+(the command line) is displayed.
+
+The list of file extensions for which the F95 dialect will be used. By +default, this is ['.f95'] +
+General user-specified options that are passed to the Fortran 95 compiler.
+Note that this variable does
+not
+contain
+-I
+(or similar) include search path options
+that scons generates automatically from $F95PATH
.
+See
+$_F95INCFLAGS
+below,
+for the variable that expands to those options.
+You only need to set $F95FLAGS
if you need to define specific
+user options for Fortran 95 files.
+You should normally set the $FORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+An automatically-generated construction variable
+containing the Fortran 95 compiler command-line options
+for specifying directories to be searched for include files.
+The value of $_F95INCFLAGS
is created
+by appending $INCPREFIX
and $INCSUFFIX
+to the beginning and end
+of each directory in $F95PATH
.
+
+The list of directories that the Fortran 95 compiler will search for include
+directories. The implicit dependency scanner will search these
+directories for include files. Don't explicitly put include directory
+arguments in $F95FLAGS
because the result will be non-portable
+and the directories will not be searched by the dependency scanner. Note:
+directory names in $F95PATH
will be looked-up relative to the SConscript
+directory when they are used in a command. To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+You only need to set $F95PATH
if you need to define a specific
+include path for Fortran 95 files.
+You should normally set the $FORTRANPATH
variable,
+which specifies the include path
+for the default Fortran compiler
+for all Fortran versions.
+
+env = Environment(F95PATH='#/include') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+include = Dir('include') +env = Environment(F95PATH=include) +
+The directory list will be added to command lines
+through the automatically-generated
+$_F95INCFLAGS
+construction variable,
+which is constructed by
+appending the values of the
+$INCPREFIX
and $INCSUFFIX
+construction variables
+to the beginning and end
+of each directory in $F95PATH
.
+Any command lines you define that need
+the F95PATH directory list should
+include $_F95INCFLAGS
:
+
+env = Environment(F95COM="my_compiler $_F95INCFLAGS -c -o $TARGET $SOURCE") +
+The command line used to compile a Fortran 95 source file to an object file
+after first running the file through the C preprocessor.
+Any options specified in the $F95FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $F95PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 95 files.
+You should normally set the $FORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 95 source file
+is compiled to an object file
+after first running the file through the C preprocessor.
+If this is not set, then $F95PPCOM
or $FORTRANPPCOM
+(the command line) is displayed.
+
+The list of file extensions for which the compilation + preprocessor pass for +F95 dialect will be used. By default, this is empty +
+A function that converts a string into a File instance relative to the +target being built. +
+A function that converts a string into a File instance relative to the +target being built. +
+The default Fortran compiler +for all versions of Fortran. +
+The command line used to compile a Fortran source file to an object file.
+By default, any options specified
+in the $FORTRANFLAGS
,
+$CPPFLAGS
,
+$_CPPDEFFLAGS
,
+$_FORTRANMODFLAG
, and
+$_FORTRANINCFLAGS
construction variables
+are included on this command line.
+
+The string displayed when a Fortran source file
+is compiled to an object file.
+If this is not set, then $FORTRANCOM
+(the command line) is displayed.
+
+The list of file extensions for which the FORTRAN dialect will be used. By +default, this is ['.f', '.for', '.ftn'] +
+General user-specified options that are passed to the Fortran compiler.
+Note that this variable does
+not
+contain
+-I
+(or similar) include or module search path options
+that scons generates automatically from $FORTRANPATH
.
+See
+$_FORTRANINCFLAGS
and $_FORTRANMODFLAG
,
+below,
+for the variables that expand those options.
+
+An automatically-generated construction variable
+containing the Fortran compiler command-line options
+for specifying directories to be searched for include
+files and module files.
+The value of $_FORTRANINCFLAGS
is created
+by respectively prepending and appending
+$INCPREFIX
and $INCSUFFIX
+to the beginning and end
+of each directory in $FORTRANPATH
.
+
+Directory location where the Fortran compiler should place +any module files it generates. This variable is empty, by default. Some +Fortran compilers will internally append this directory in the search path +for module files, as well. +
+The prefix used to specify a module directory on the Fortran compiler command
+line.
+This will be prepended to the beginning of the directory
+in the $FORTRANMODDIR
construction variables
+when the $_FORTRANMODFLAG
variables is automatically generated.
+
+The suffix used to specify a module directory on the Fortran compiler command
+line.
+This will be appended to the end of the directory
+in the $FORTRANMODDIR
construction variables
+when the $_FORTRANMODFLAG
variables is automatically generated.
+
+An automatically-generated construction variable
+containing the Fortran compiler command-line option
+for specifying the directory location where the Fortran
+compiler should place any module files that happen to get
+generated during compilation.
+The value of $_FORTRANMODFLAG
is created
+by respectively prepending and appending
+$FORTRANMODDIRPREFIX
and $FORTRANMODDIRSUFFIX
+to the beginning and end of the directory in $FORTRANMODDIR
.
+
+The module file prefix used by the Fortran compiler. SCons assumes that
+the Fortran compiler follows the quasi-standard naming convention for
+module files of
+module_name.mod
.
+As a result, this variable is left empty, by default. For situations in
+which the compiler does not necessarily follow the normal convention,
+the user may use this variable. Its value will be appended to every
+module file name as scons attempts to resolve dependencies.
+
+The module file suffix used by the Fortran compiler. SCons assumes that
+the Fortran compiler follows the quasi-standard naming convention for
+module files of
+module_name.mod
.
+As a result, this variable is set to ".mod", by default. For situations
+in which the compiler does not necessarily follow the normal convention,
+the user may use this variable. Its value will be appended to every
+module file name as scons attempts to resolve dependencies.
+
+The list of directories that the Fortran compiler will search for
+include files and (for some compilers) module files. The Fortran implicit
+dependency scanner will search these directories for include files (but
+not module files since they are autogenerated and, as such, may not
+actually exist at the time the scan takes place). Don't explicitly put
+include directory arguments in FORTRANFLAGS because the result will be
+non-portable and the directories will not be searched by the dependency
+scanner. Note: directory names in FORTRANPATH will be looked-up relative
+to the SConscript directory when they are used in a command. To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+
+env = Environment(FORTRANPATH='#/include') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+include = Dir('include') +env = Environment(FORTRANPATH=include) +
+The directory list will be added to command lines
+through the automatically-generated
+$_FORTRANINCFLAGS
+construction variable,
+which is constructed by
+respectively prepending and appending the values of the
+$INCPREFIX
and $INCSUFFIX
+construction variables
+to the beginning and end
+of each directory in $FORTRANPATH
.
+Any command lines you define that need
+the FORTRANPATH directory list should
+include $_FORTRANINCFLAGS
:
+
+env = Environment(FORTRANCOM="my_compiler $_FORTRANINCFLAGS -c -o $TARGET $SOURCE") +
+The command line used to compile a Fortran source file to an object file
+after first running the file through the C preprocessor.
+By default, any options specified in the $FORTRANFLAGS
,
+$CPPFLAGS
,
+$_CPPDEFFLAGS
,
+$_FORTRANMODFLAG
, and
+$_FORTRANINCFLAGS
+construction variables are included on this command line.
+
+The string displayed when a Fortran source file
+is compiled to an object file
+after first running the file through the C preprocessor.
+If this is not set, then $FORTRANPPCOM
+(the command line) is displayed.
+
+The list of file extensions for which the compilation + preprocessor pass for +FORTRAN dialect will be used. By default, this is ['.fpp', '.FPP'] +
+The list of suffixes of files that will be scanned +for Fortran implicit dependencies +(INCLUDE lines and USE statements). +The default list is: +
+[".f", ".F", ".for", ".FOR", ".ftn", ".FTN", ".fpp", ".FPP", +".f77", ".F77", ".f90", ".F90", ".f95", ".F95"] +
+ On Mac OS X with gcc,
+ a list containing the paths to search for frameworks.
+ Used by the compiler to find framework-style includes like
+ #include <Fmwk/Header.h>.
+ Used by the linker to find user-specified frameworks when linking (see
+ $FRAMEWORKS
).
+ For example:
+
+ env.AppendUnique(FRAMEWORKPATH='#myframeworkdir') +
+ will add +
+ ... -Fmyframeworkdir +
+ to the compiler and linker command lines. +
+ On Mac OS X with gcc, an automatically-generated construction variable
+ containing the linker command-line options corresponding to
+ $FRAMEWORKPATH
.
+
+ On Mac OS X with gcc, the prefix to be used for the FRAMEWORKPATH entries.
+ (see $FRAMEWORKPATH
).
+ The default value is
+ -F
.
+
+ On Mac OS X with gcc,
+ the prefix to be used for linking in frameworks
+ (see $FRAMEWORKS
).
+ The default value is
+ -framework
.
+
+ On Mac OS X with gcc, + an automatically-generated construction variable + containing the linker command-line options + for linking with FRAMEWORKS. +
+ On Mac OS X with gcc, a list of the framework names to be linked into a + program or shared library or bundle. + The default value is the empty list. + For example: +
+ env.AppendUnique(FRAMEWORKS=Split('System Cocoa SystemConfiguration')) +
+ On Mac OS X with gcc,
+ general user-supplied frameworks options to be added at
+ the end of a command
+ line building a loadable module.
+ (This has been largely superseded by
+ the $FRAMEWORKPATH
, $FRAMEWORKPATHPREFIX
,
+ $FRAMEWORKPREFIX
and $FRAMEWORKS
variables
+ described above.)
+
+The Ghostscript program used, e.g. to convert PostScript to PDF files. +
+The full Ghostscript command line used for the conversion process. Its default
+value is “$GS $GSFLAGS -sOutputFile=$TARGET $SOURCES
”.
+
+The string displayed when
+Ghostscript is called for the conversion process.
+If this is not set (the default), then $GSCOM
(the command line) is displayed.
+
+General options passed to the Ghostscript program,
+when converting PostScript to PDF files for example. Its default value
+is “-dNOPAUSE -dBATCH -sDEVICE=pdfwrite
”
+
+ The name of the host hardware architecture used to create the Environment. + If a platform is specified when creating the Environment, then + that Platform's logic will handle setting this value. + This value is immutable, and should not be changed by the user after + the Environment is initialized. + Currently only set for Win32. +
+Sets the host architecture for Visual Studio compiler. If not set, +default to the detected host architecture: note that this may depend +on the python you are using. +This variable must be passed as an argument to the Environment() +constructor; setting it later has no effect. +
+Valid values are the same as for $TARGET_ARCH
.
+
+This is currently only used on Windows, but in the future it will be +used on other OSes as well. +
+ The name of the host operating system used to create the Environment. + If a platform is specified when creating the Environment, then + that Platform's logic will handle setting this value. + This value is immutable, and should not be changed by the user after + the Environment is initialized. + Currently only set for Win32. +
+The list of suffixes of files that will be scanned +for IDL implicit dependencies +(#include or import lines). +The default list is: +
+[".idl", ".IDL"] +
+Used to override $SHLIBNOVERSIONSYMLINKS
/$LDMODULENOVERSIONSYMLINKS
when
+creating versioned import library for a shared library/loadable module. If not defined,
+then $SHLIBNOVERSIONSYMLINKS
/$LDMODULENOVERSIONSYMLINKS
is used to determine
+whether to disable symlink generation or not.
+
+The prefix used for import library names. For example, cygwin uses import
+libraries (libfoo.dll.a
) in pair with dynamic libraries
+(cygfoo.dll
). The cyglink
linker sets
+$IMPLIBPREFIX
to 'lib'
and $SHLIBPREFIX
+to 'cyg'
.
+
+The suffix used for import library names. For example, cygwin uses import
+libraries (libfoo.dll.a
) in pair with dynamic libraries
+(cygfoo.dll
). The cyglink
linker sets
+$IMPLIBSUFFIX
to '.dll.a'
and $SHLIBSUFFIX
+to '.dll'
.
+
+Used to override $SHLIBVERSION
/$LDMODULEVERSION
when
+generating versioned import library for a shared library/loadable module. If
+undefined, the $SHLIBVERSION
/$LDMODULEVERSION
is used to
+determine the version of versioned import library.
+
+Controls whether or not SCons will +add implicit dependencies for the commands +executed to build targets. +
+By default, SCons will add
+to each target
+an implicit dependency on the command
+represented by the first argument on any
+command line it executes.
+The specific file for the dependency is
+found by searching the
+PATH
+variable in the
+ENV
+environment used to execute the command.
+
+If the construction variable
+$IMPLICIT_COMMAND_DEPENDENCIES
+is set to a false value
+(None
,
+False
,
+0
,
+etc.),
+then the implicit dependency will
+not be added to the targets
+built with that construction environment.
+
+env = Environment(IMPLICIT_COMMAND_DEPENDENCIES = 0) +
+The prefix used to specify an include directory on the C compiler command
+line.
+This will be prepended to the beginning of each directory
+in the $CPPPATH
and $FORTRANPATH
construction variables
+when the $_CPPINCFLAGS
and $_FORTRANINCFLAGS
+variables are automatically generated.
+
+The suffix used to specify an include directory on the C compiler command
+line.
+This will be appended to the end of each directory
+in the $CPPPATH
and $FORTRANPATH
construction variables
+when the $_CPPINCFLAGS
and $_FORTRANINCFLAGS
+variables are automatically generated.
+
+A function to be called to install a file into a +destination file name. +The default function copies the file into the destination +(and sets the destination file's mode and permission bits +to match the source file's). +The function takes the following arguments: +
+def install(dest, source, env): +
+dest
+is the path name of the destination file.
+source
+is the path name of the source file.
+env
+is the construction environment
+(a dictionary of construction values)
+in force for this file installation.
+
+The string displayed when a file is +installed into a destination file name. +The default is: +
+Install file: "$SOURCE" as "$TARGET" +
+Set by the "intelc" Tool +to the major version number of the Intel C compiler +selected for use. +
+The Java archive tool. +
+The Java archive tool. +
+The directory to which the Java archive tool should change
+(using the
+-C
+option).
+
+The directory to which the Java archive tool should change
+(using the
+-C
+option).
+
+The command line used to call the Java archive tool. +
+The command line used to call the Java archive tool. +
+The string displayed when the Java archive tool
+is called
+If this is not set, then $JARCOM
(the command line) is displayed.
+
+env = Environment(JARCOMSTR = "JARchiving $SOURCES into $TARGET") +
+The string displayed when the Java archive tool
+is called
+If this is not set, then $JARCOM
(the command line) is displayed.
+
+env = Environment(JARCOMSTR = "JARchiving $SOURCES into $TARGET") +
+General options passed to the Java archive tool.
+By default this is set to
+cf
+to create the necessary
+jar
+file.
+
+General options passed to the Java archive tool.
+By default this is set to
+cf
+to create the necessary
+jar
+file.
+
+The suffix for Java archives:
+.jar
+by default.
+
+The suffix for Java archives:
+.jar
+by default.
+
+ Specifies the list of directories that
+ will be added to the
+ javac command line
+ via the -bootclasspath
option.
+ The individual directory names will be
+ separated by the operating system's path separate character
+ (:
on UNIX/Linux/POSIX,
+ ;
+ on Windows).
+
+ The Java compiler. +
+ The command line used to compile a directory tree containing
+ Java source files to
+ corresponding Java class files.
+ Any options specified in the $JAVACFLAGS
construction variable
+ are included on this command line.
+
+ The string displayed when compiling
+ a directory tree of Java source files to
+ corresponding Java class files.
+ If this is not set, then $JAVACCOM
(the command line) is displayed.
+
+ env = Environment(JAVACCOMSTR = "Compiling class files $TARGETS from $SOURCES") +
+ General options that are passed to the Java compiler. +
+ The directory in which Java class files may be found.
+ This is stripped from the beginning of any Java .class
+ file names supplied to the
+ JavaH
+ builder.
+
+ Specifies the list of directories that
+ will be searched for Java
+ .class
+ file.
+ The directories in this list will be added to the
+ javac and javah command lines
+ via the -classpath
option.
+ The individual directory names will be
+ separated by the operating system's path separate character
+ (:
on UNIX/Linux/POSIX,
+ ;
+ on Windows).
+
+ Note that this currently just adds the specified
+ directory via the -classpath
option.
+ SCons does not currently search the
+ $JAVACLASSPATH
directories for dependency
+ .class
+ files.
+
+ The suffix for Java class files;
+ .class
+ by default.
+
+The Java generator for C header and stub files. +
+The command line used to generate C header and stub files
+from Java classes.
+Any options specified in the $JAVAHFLAGS
construction variable
+are included on this command line.
+
+The string displayed when C header and stub files
+are generated from Java classes.
+If this is not set, then $JAVAHCOM
(the command line) is displayed.
+
+env = Environment(JAVAHCOMSTR = "Generating header/stub file(s) $TARGETS from $SOURCES") +
+General options passed to the C header and stub file generator +for Java classes. +
+ Include path for Java header files (such as jni.h) +
+ Specifies the list of directories that
+ will be searched for input
+ .java
+ file.
+ The directories in this list will be added to the
+ javac command line
+ via the -sourcepath
option.
+ The individual directory names will be
+ separated by the operating system's path separate character
+ (:
on UNIX/Linux/POSIX,
+ ;
+ on Windows).
+
+ Note that this currently just adds the specified
+ directory via the -sourcepath
option.
+ SCons does not currently search the
+ $JAVASOURCEPATH
directories for dependency
+ .java
+ files.
+
+ The suffix for Java files;
+ .java
+ by default.
+
+ Specifies the Java version being used by the Java
builder.
+ This is not currently used to select one
+ version of the Java compiler vs. another.
+ Instead, you should set this to specify the version of Java
+ supported by your javac compiler.
+ The default is 1.4
.
+
+ This is sometimes necessary because
+ Java 1.5 changed the file names that are created
+ for nested anonymous inner classes,
+ which can cause a mismatch with the files
+ that SCons expects will be generated by the javac compiler.
+ Setting $JAVAVERSION
to
+ 1.5
+ (or 1.6
, as appropriate)
+ can make SCons realize that a Java 1.5 or 1.6
+ build is actually up to date.
+
+The LaTeX structured formatter and typesetter. +
+The command line used to call the LaTeX structured formatter and typesetter. +
+The string displayed when calling
+the LaTeX structured formatter and typesetter.
+If this is not set, then $LATEXCOM
(the command line) is displayed.
+
+env = Environment(LATEXCOMSTR = "Building $TARGET from LaTeX input $SOURCES") +
+General options passed to the LaTeX structured formatter and typesetter. +
+The maximum number of times that LaTeX
+will be re-run if the
+.log
+generated by the $LATEXCOM
command
+indicates that there are undefined references.
+The default is to try to resolve undefined references
+by re-running LaTeX up to three times.
+
+The list of suffixes of files that will be scanned
+for LaTeX implicit dependencies
+(\include
or \import
files).
+The default list is:
+
+[".tex", ".ltx", ".latex"] +
+The linker for building loadable modules.
+By default, this is the same as $SHLINK
.
+
+The command line for building loadable modules.
+On Mac OS X, this uses the $LDMODULE
,
+$LDMODULEFLAGS
and
+$FRAMEWORKSFLAGS
variables.
+On other systems, this is the same as $SHLINK
.
+
+The string displayed when building loadable modules.
+If this is not set, then $LDMODULECOM
(the command line) is displayed.
+
+General user options passed to the linker for building loadable modules. +
+Instructs the LoadableModule
builder to not automatically create symlinks
+for versioned modules. Defaults to $SHLIBNOVERSIONSYMLINKS
+
+The prefix used for loadable module file names.
+On Mac OS X, this is null;
+on other systems, this is
+the same as $SHLIBPREFIX
.
+
+A macro that automatically generates loadable module's SONAME based on $TARGET,
+$LDMODULEVERSION and $LDMODULESUFFIX. Used by LoadableModule
builder
+when the linker tool supports SONAME (e.g. gnulink
).
+
+The suffix used for loadable module file names. +On Mac OS X, this is null; +on other systems, this is +the same as $SHLIBSUFFIX. +
+When this construction variable is defined, a versioned loadable module
+is created by LoadableModule
builder. This activates the
+$_LDMODULEVERSIONFLAGS
and thus modifies the $LDMODULECOM
as
+required, adds the version number to the library name, and creates the symlinks
+that are needed. $LDMODULEVERSION
versions should exist in the same
+format as $SHLIBVERSION
.
+
+Extra flags added to $LDMODULECOM
when building versioned
+LoadableModule
. These flags are only used when $LDMODULEVERSION
is
+set.
+
+This macro automatically introduces extra flags to $LDMODULECOM
when
+building versioned LoadableModule
(that is when
+$LDMODULEVERSION
is set). _LDMODULEVERSIONFLAGS
+usually adds $SHLIBVERSIONFLAGS
and some extra dynamically generated
+options (such as -Wl,-soname=$_LDMODULESONAME
). It is unused
+by plain (unversioned) loadable modules.
+
+The lexical analyzer generator. +
+The command line used to call the lexical analyzer generator +to generate a source file. +
+The string displayed when generating a source file
+using the lexical analyzer generator.
+If this is not set, then $LEXCOM
(the command line) is displayed.
+
+env = Environment(LEXCOMSTR = "Lex'ing $TARGET from $SOURCES") +
+General options passed to the lexical analyzer generator. +
+An automatically-generated construction variable
+containing the linker command-line options
+for specifying directories to be searched for library.
+The value of $_LIBDIRFLAGS
is created
+by respectively prepending and appending $LIBDIRPREFIX
and $LIBDIRSUFFIX
+to the beginning and end
+of each directory in $LIBPATH
.
+
+The prefix used to specify a library directory on the linker command line.
+This will be prepended to the beginning of each directory
+in the $LIBPATH
construction variable
+when the $_LIBDIRFLAGS
variable is automatically generated.
+
+The suffix used to specify a library directory on the linker command line.
+This will be appended to the end of each directory
+in the $LIBPATH
construction variable
+when the $_LIBDIRFLAGS
variable is automatically generated.
+
+TODO +
+An automatically-generated construction variable
+containing the linker command-line options
+for specifying libraries to be linked with the resulting target.
+The value of $_LIBFLAGS
is created
+by respectively prepending and appending $LIBLINKPREFIX
and $LIBLINKSUFFIX
+to the beginning and end
+of each filename in $LIBS
.
+
+The prefix used to specify a library to link on the linker command line.
+This will be prepended to the beginning of each library
+in the $LIBS
construction variable
+when the $_LIBFLAGS
variable is automatically generated.
+
+The suffix used to specify a library to link on the linker command line.
+This will be appended to the end of each library
+in the $LIBS
construction variable
+when the $_LIBFLAGS
variable is automatically generated.
+
+The list of directories that will be searched for libraries.
+The implicit dependency scanner will search these
+directories for include files. Don't explicitly put include directory
+arguments in $LINKFLAGS
or $SHLINKFLAGS
+because the result will be non-portable
+and the directories will not be searched by the dependency scanner. Note:
+directory names in LIBPATH will be looked-up relative to the SConscript
+directory when they are used in a command. To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+
+env = Environment(LIBPATH='#/libs') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+libs = Dir('libs') +env = Environment(LIBPATH=libs) +
+The directory list will be added to command lines
+through the automatically-generated
+$_LIBDIRFLAGS
+construction variable,
+which is constructed by
+respectively prepending and appending the values of the
+$LIBDIRPREFIX
and $LIBDIRSUFFIX
+construction variables
+to the beginning and end
+of each directory in $LIBPATH
.
+Any command lines you define that need
+the LIBPATH directory list should
+include $_LIBDIRFLAGS
:
+
+env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE") +
+The prefix used for (static) library file names. +A default value is set for each platform +(posix, win32, os2, etc.), +but the value is overridden by individual tools +(ar, mslib, sgiar, sunar, tlib, etc.) +to reflect the names of the libraries they create. +
+A list of all legal prefixes for library file names.
+When searching for library dependencies,
+SCons will look for files with these prefixes,
+the base library name,
+and suffixes in the $LIBSUFFIXES
list.
+
+A list of one or more libraries +that will be linked with +any executable programs +created by this environment. +
+The library list will be added to command lines
+through the automatically-generated
+$_LIBFLAGS
+construction variable,
+which is constructed by
+respectively prepending and appending the values of the
+$LIBLINKPREFIX
and $LIBLINKSUFFIX
+construction variables
+to the beginning and end
+of each filename in $LIBS
.
+Any command lines you define that need
+the LIBS library list should
+include $_LIBFLAGS
:
+
+env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE") +
+If you add a
+File
+object to the
+$LIBS
+list, the name of that file will be added to
+$_LIBFLAGS
,
+and thus the link line, as is, without
+$LIBLINKPREFIX
+or
+$LIBLINKSUFFIX
.
+For example:
+
+env.Append(LIBS=File('/tmp/mylib.so')) +
+In all cases, scons will add dependencies from the executable program to +all the libraries in this list. +
+The suffix used for (static) library file names. +A default value is set for each platform +(posix, win32, os2, etc.), +but the value is overridden by individual tools +(ar, mslib, sgiar, sunar, tlib, etc.) +to reflect the names of the libraries they create. +
+A list of all legal suffixes for library file names.
+When searching for library dependencies,
+SCons will look for files with prefixes, in the $LIBPREFIXES
list,
+the base library name,
+and these suffixes.
+
+The abbreviated name, preferably the SPDX code, of the license under which +this project is released (GPL-3.0, LGPL-2.1, BSD-2-Clause etc.). +See http://www.opensource.org/licenses/alphabetical +for a list of license names and SPDX codes. +
+The separator used by the Substfile
and Textfile
builders.
+This value is used between sources when constructing the target.
+It defaults to the current system line separator.
+
+The $LINGUAS_FILE
defines file(s) containing list of additional linguas
+to be processed by POInit
, POUpdate
or MOFiles
+builders. It also affects Translate
builder. If the variable contains
+a string, it defines name of the list file. The $LINGUAS_FILE
may be a
+list of file names as well. If $LINGUAS_FILE
is set to
+True
(or non-zero numeric value), the list will be read from
+default file named
+LINGUAS
.
+
+The linker. +
+The command line used to link object files into an executable. +
+The string displayed when object files
+are linked into an executable.
+If this is not set, then $LINKCOM
(the command line) is displayed.
+
+env = Environment(LINKCOMSTR = "Linking $TARGET") +
+General user options passed to the linker.
+Note that this variable should
+not
+contain
+-l
+(or similar) options for linking with the libraries listed in $LIBS
,
+nor
+-L
+(or similar) library search path options
+that scons generates automatically from $LIBPATH
.
+See
+$_LIBFLAGS
+above,
+for the variable that expands to library-link options,
+and
+$_LIBDIRFLAGS
+above,
+for the variable that expands to library search path options.
+
+The M4 macro preprocessor. +
+The command line used to pass files through the M4 macro preprocessor. +
+The string displayed when
+a file is passed through the M4 macro preprocessor.
+If this is not set, then $M4COM
(the command line) is displayed.
+
+General options passed to the M4 macro preprocessor. +
+The makeindex generator for the TeX formatter and typesetter and the +LaTeX structured formatter and typesetter. +
+The command line used to call the makeindex generator for the +TeX formatter and typesetter and the LaTeX structured formatter and +typesetter. +
+The string displayed when calling the makeindex generator for the
+TeX formatter and typesetter
+and the LaTeX structured formatter and typesetter.
+If this is not set, then $MAKEINDEXCOM
(the command line) is displayed.
+
+General options passed to the makeindex generator for the TeX formatter +and typesetter and the LaTeX structured formatter and typesetter. +
+The maximum number of characters allowed on an external command line. +On Win32 systems, +link lines longer than this many characters +are linked via a temporary file name. +
+The Microsoft IDL compiler. +
+The command line used to pass files to the Microsoft IDL compiler. +
+The string displayed when
+the Microsoft IDL copmiler is called.
+If this is not set, then $MIDLCOM
(the command line) is displayed.
+
+General options passed to the Microsoft IDL compiler. +
+Suffix used for MO
files (default: '.mo'
).
+See msgfmt
tool and MOFiles
builder.
+
+Absolute path to msgfmt(1) binary, found by
+Detect()
.
+See msgfmt
tool and MOFiles
builder.
+
+Complete command line to run msgfmt(1) program.
+See msgfmt
tool and MOFiles
builder.
+
+String to display when msgfmt(1) is invoked
+(default: ''
, which means ``print $MSGFMTCOM
'').
+See msgfmt
tool and MOFiles
builder.
+
+Additional flags to msgfmt(1).
+See msgfmt
tool and MOFiles
builder.
+
+Path to msginit(1) program (found via
+Detect()
).
+See msginit
tool and POInit
builder.
+
+Complete command line to run msginit(1) program.
+See msginit
tool and POInit
builder.
+
+String to display when msginit(1) is invoked
+(default: ''
, which means ``print $MSGINITCOM
'').
+See msginit
tool and POInit
builder.
+
+List of additional flags to msginit(1) (default:
+[]
).
+See msginit
tool and POInit
builder.
+
+Internal ``macro''. Computes locale (language) name based on target filename
+(default: '${TARGET.filebase}'
).
+
+Absolute path to msgmerge(1) binary as found by
+Detect()
.
+See msgmerge
tool and POUpdate
builder.
+
+Complete command line to run msgmerge(1) command.
+See msgmerge
tool and POUpdate
builder.
+
+String to be displayed when msgmerge(1) is invoked
+(default: ''
, which means ``print $MSGMERGECOM
'').
+See msgmerge
tool and POUpdate
builder.
+
+Additional flags to msgmerge(1) command.
+See msgmerge
tool and POUpdate
builder.
+
+The directory containing the Microsoft SDK +(either Platform SDK or Windows SDK) +to be used for compilation. +
+The version string of the Microsoft SDK
+(either Platform SDK or Windows SDK)
+to be used for compilation.
+Supported versions include
+6.1
,
+6.0A
,
+6.0
,
+2003R2
+and
+2003R1
.
+
+When set to any true value,
+specifies that SCons should batch
+compilation of object files
+when calling the Microsoft Visual C/C++ compiler.
+All compilations of source files from the same source directory
+that generate target files in a same output directory
+and were configured in SCons using the same construction environment
+will be built in a single call to the compiler.
+Only source files that have changed since their
+object files were built will be passed to each compiler invocation
+(via the $CHANGED_SOURCES
construction variable).
+Any compilations where the object (target) file base name
+(minus the .obj
)
+does not match the source file base name
+will be compiled separately.
+
+Use a batch script to set up Microsoft Visual Studio compiler +
+$MSVC_USE_SCRIPT
overrides $MSVC_VERSION
and $TARGET_ARCH
.
+If set to the name of a Visual Studio .bat file (e.g. vcvars.bat),
+SCons will run that bat file and extract the relevant variables from
+the result (typically %INCLUDE%, %LIB%, and %PATH%). Setting
+MSVC_USE_SCRIPT to None bypasses the Visual Studio autodetection
+entirely; use this if you are running SCons in a Visual Studio cmd
+window and importing the shell's environment variables.
+
+Build libraries for a Universal Windows Platform (UWP) Application. +
+If $MSVC_UWP_APP
is set, the Visual Studio environment will be set up to point
+to the Windows Store compatible libraries and Visual Studio runtimes. In doing so,
+any libraries that are built will be able to be used in a UWP App and published
+to the Windows Store.
+This flag will only have an effect with Visual Studio 2015+.
+This variable must be passed as an argument to the Environment()
+constructor; setting it later has no effect.
+
+Valid values are '1' or '0' +
+Sets the preferred version of Microsoft Visual C/C++ to use. +
+If $MSVC_VERSION
is not set, SCons will (by default) select the
+latest version of Visual C/C++ installed on your system. If the
+specified version isn't installed, tool initialization will fail.
+This variable must be passed as an argument to the Environment()
+constructor; setting it later has no effect.
+
+Valid values for Windows are
+14.0
,
+14.0Exp
,
+12.0
,
+12.0Exp
,
+11.0
,
+11.0Exp
,
+10.0
,
+10.0Exp
,
+9.0
,
+9.0Exp
,
+8.0
,
+8.0Exp
,
+7.1
,
+7.0
,
+and 6.0
.
+Versions ending in Exp
refer to "Express" or
+"Express for Desktop" editions.
+
+When the Microsoft Visual Studio tools are initialized, they set up this +dictionary with the following keys:
the version of MSVS being used (can be set via
+ $MSVS_VERSION
)
the available versions of MSVS installed
installed directory of Visual C++
installed directory of Visual Studio
installed directory of the .NET framework
list of installed versions of the .NET framework, sorted + latest to oldest.
latest installed version of the .NET + framework
installed location of the .NET SDK.
installed location of the Platform SDK.
dictionary of installed Platform SDK modules, where the + dictionary keys are keywords for the various modules, and the values + are 2-tuples where the first is the release date, and the second is + the version number.
If a value isn't set, it wasn't available in the +registry.
Sets +the architecture for which the generated project(s) should build.
The default value is x86
. amd64
is
+also supported by SCons for some Visual Studio versions. Trying to set
+$MSVS_ARCH
to an architecture that's not supported for a given Visual
+Studio version will generate an error.
The string placed in a generated
+Microsoft Visual Studio project file as the value of the
+ProjectGUID
attribute. There is no default value. If not
+defined, a new GUID is generated.
The path name placed in a generated
+Microsoft Visual Studio project file as the value of the
+SccAuxPath
attribute if the
+MSVS_SCC_PROVIDER
construction variable is also set. There is
+no default value.
The root path of projects in
+your SCC workspace, i.e the path under which all project and solution files
+will be generated. It is used as a reference path from which the relative
+paths of the generated Microsoft Visual Studio project and solution files are
+computed. The relative project file path is placed as the value of the
+SccLocalPath
attribute of the project file and as the
+values of the
+SccProjectFilePathRelativizedFromConnection[i]
(where [i]
+ranges from 0 to the number of projects in the solution) attributes of the
+GlobalSection(SourceCodeControl)
section of the Microsoft
+Visual Studio solution file. Similarly the relative solution file path is
+placed as the values of the SccLocalPath[i]
(where [i]
+ranges from 0 to the number of projects in the solution) attributes of the
+GlobalSection(SourceCodeControl)
section of the Microsoft
+Visual Studio solution file. This is used only if the
+MSVS_SCC_PROVIDER
construction variable is also set. The
+default value is the current working directory.
The project name placed in
+a generated Microsoft Visual Studio project file as the value of the
+SccProjectName
attribute if the
+MSVS_SCC_PROVIDER
construction variable is also set. In this
+case the string is also placed in the SccProjectName0
+attribute of the GlobalSection(SourceCodeControl)
section
+of the Microsoft Visual Studio solution file. There is no default value.
+
The
+string placed in a generated Microsoft Visual Studio project file as the value
+of the SccProvider
attribute. The string is also placed in
+the SccProvider0
attribute of the
+GlobalSection(SourceCodeControl)
section of the Microsoft
+Visual Studio solution file. There is no default value.
Sets the preferred version +of Microsoft Visual Studio to use.
If $MSVS_VERSION
is not
+set, SCons will (by default) select the latest version of Visual Studio
+installed on your system. So, if you have version 6 and version 7 (MSVS .NET)
+installed, it will prefer version 7. You can override this by specifying the
+MSVS_VERSION
variable in the Environment initialization,
+setting it to the appropriate version ('6.0' or '7.0', for example). If the
+specified version isn't installed, tool initialization will fail.
This is obsolete: use $MSVC_VERSION
instead. If $MSVS_VERSION
is
+set and $MSVC_VERSION
is not, $MSVC_VERSION
will be set automatically
+to $MSVS_VERSION
. If both are set to different values, scons will raise an
+error.
The build command line placed in a generated Microsoft Visual Studio +project file. The default is to have Visual Studio invoke SCons with any +specified build targets.
The clean command line placed in a generated Microsoft Visual +Studio project file. The default is to have Visual Studio invoke SCons with +the -c option to remove any specified targets.
The encoding string placed in a
+generated Microsoft Visual Studio project file. The default is encoding
+Windows-1252
.
The action used to generate Microsoft +Visual Studio project files.
The suffix used for Microsoft Visual
+Studio project (DSP) files. The default value is .vcproj
+when using Visual Studio version 7.x (.NET) or later version, and
+.dsp
when using earlier versions of Visual Studio.
+
The +rebuild command line placed in a generated Microsoft Visual Studio project +file. The default is to have Visual Studio invoke SCons with any specified +rebuild targets.
The SCons used in generated Microsoft Visual Studio project files. The +default is the version of SCons being used to generate the project file. +
The default +SCons command used in generated Microsoft Visual Studio project files.
The sconscript
+file (that is, SConstruct
or SConscript
file) that will be invoked by
+Visual Studio project files (through the $MSVSSCONSCOM
variable). The
+default is the same sconscript file that contains the call to MSVSProject
+to build the project file.
The +SCons flags used in generated Microsoft Visual Studio project files.
The action used to generate Microsoft +Visual Studio solution files.
The suffix used for Microsoft
+Visual Studio solution (DSW) files. The default value is
+.sln
when using Visual Studio version 7.x (.NET), and
+.dsw
when using earlier versions of Visual Studio.
+
+The program used on Windows systems to embed manifests into DLLs and EXEs.
+See also $WINDOWS_EMBED_MANIFEST
.
+
+The Windows command line used to embed manifests into executables.
+See also $MTSHLIBCOM
.
+
+Flags passed to the $MT
manifest embedding program (Windows only).
+
+The Windows command line used to embed manifests into shared libraries (DLLs).
+See also $MTEXECOM
.
+
+The version number of the MetroWerks CodeWarrior C compiler +to be used. +
+A list of installed versions of the MetroWerks CodeWarrior C compiler +on this system. +
+Specfies the name of the project to package. +
+When set to non-zero,
+suppresses creation of a corresponding Windows static import lib by the
+SharedLibrary
+builder when used with
+MinGW, Microsoft Visual Studio or Metrowerks.
+This also suppresses creation
+of an export (.exp) file
+when using Microsoft Visual Studio.
+
+The prefix used for (static) object file names. +
+The suffix used for (static) object file names. +
+Specifies the directory where all files in resulting archive will be +placed if applicable. The default value is "$NAME-$VERSION". +
+Selects the package type to build. Currently these are available: +
+ * msi - Microsoft Installer + * rpm - Redhat Package Manger + * ipkg - Itsy Package Management System + * tarbz2 - compressed tar + * targz - compressed tar + * zip - zip file + * src_tarbz2 - compressed tar source + * src_targz - compressed tar source + * src_zip - zip file source +
+This may be overridden with the "package_type" command line option. +
+The version of the package (not the underlying project). +This is currently only used by the rpm packager +and should reflect changes in the packaging, +not the underlying project code itself. +
+The Microsoft Visual C++ precompiled header that will be used when compiling +object files. This variable is ignored by tools other than Microsoft Visual C++. +When this variable is +defined SCons will add options to the compiler command line to +cause it to use the precompiled header, and will also set up the +dependencies for the PCH file. +Example: +
+env['PCH'] = 'StdAfx.pch' +
+The command line used by the
+PCH
+builder to generated a precompiled header.
+
+The string displayed when generating a precompiled header.
+If this is not set, then $PCHCOM
(the command line) is displayed.
+
+A construction variable that, when expanded,
+adds the /yD
flag to the command line
+only if the $PDB
construction variable is set.
+
+This variable specifies how much of a source file is precompiled. This +variable is ignored by tools other than Microsoft Visual C++, or when +the PCH variable is not being used. When this variable is define it +must be a string that is the name of the header that +is included at the end of the precompiled portion of the source files, or +the empty string if the "#pragma hrdstop" construct is being used: +
+env['PCHSTOP'] = 'StdAfx.h' +
+The Microsoft Visual C++ PDB file that will store debugging information for +object files, shared libraries, and programs. This variable is ignored by +tools other than Microsoft Visual C++. +When this variable is +defined SCons will add options to the compiler and linker command line to +cause them to generate external debugging information, and will also set up the +dependencies for the PDB file. +Example: +
+env['PDB'] = 'hello.pdb' +
+The Visual C++ compiler switch that SCons uses by default
+to generate PDB information is /Z7
.
+This works correctly with parallel (-j
) builds
+because it embeds the debug information in the intermediate object files,
+as opposed to sharing a single PDB file between multiple object files.
+This is also the only way to get debug information
+embedded into a static library.
+Using the /Zi
instead may yield improved
+link-time performance,
+although parallel builds will no longer work.
+You can generate PDB files with the /Zi
+switch by overriding the default $CCPDBFLAGS
variable;
+see the entry for that variable for specific examples.
+
+A deprecated synonym for $DVIPDFCOM
.
+
+The pdflatex utility. +
+The command line used to call the pdflatex utility. +
+The string displayed when calling the pdflatex utility.
+If this is not set, then $PDFLATEXCOM
(the command line) is displayed.
+
+env = Environment(PDFLATEX;COMSTR = "Building $TARGET from LaTeX input $SOURCES") +
+General options passed to the pdflatex utility. +
+The prefix used for PDF file names. +
+The suffix used for PDF file names. +
+The pdftex utility. +
+The command line used to call the pdftex utility. +
+The string displayed when calling the pdftex utility.
+If this is not set, then $PDFTEXCOM
(the command line) is displayed.
+
+env = Environment(PDFTEXCOMSTR = "Building $TARGET from TeX input $SOURCES") +
+General options passed to the pdftex utility. +
+On Solaris systems,
+the package-checking program that will
+be used (along with $PKGINFO
)
+to look for installed versions of
+the Sun PRO C++ compiler.
+The default is
+/usr/sbin/pgkchk
.
+
+On Solaris systems,
+the package information program that will
+be used (along with $PKGCHK
)
+to look for installed versions of
+the Sun PRO C++ compiler.
+The default is
+pkginfo
.
+
+The name of the platform used to create the Environment. If no platform is
+specified when the Environment is created,
+scons
+autodetects the platform.
+
+env = Environment(tools = []) +if env['PLATFORM'] == 'cygwin': + Tool('mingw')(env) +else: + Tool('msvc')(env) +
+The $POAUTOINIT
variable, if set to True
(on non-zero
+numeric value), let the msginit
tool to automatically initialize
+missing PO
files with
+msginit(1). This applies to both,
+POInit
and POUpdate
builders (and others that use any of
+them).
+
+Common alias for all PO
files created with POInit
+builder (default: 'po-create'
).
+See msginit
tool and POInit
builder.
+
+Suffix used for PO
files (default: '.po'
)
+See msginit
tool and POInit
builder.
+
+The $POTDOMAIN
defines default domain, used to generate
+POT
filename as
when
+no $POTDOMAIN
.potPOT
file name is provided by the user. This applies to
+POTUpdate
, POInit
and POUpdate
builders (and
+builders, that use them, e.g. Translate
). Normally (if $POTDOMAIN
is
+not defined), the builders use messages.pot
as default
+POT
file name.
+
+Suffix used for PO Template files (default: '.pot'
).
+See xgettext
tool and POTUpdate
builder.
+
+Name of the common phony target for all PO Templates created with
+POUpdate
(default: 'pot-update'
).
+See xgettext
tool and POTUpdate
builder.
+
+Common alias for all PO
files being defined with
+POUpdate
builder (default: 'po-update'
).
+See msgmerge
tool and POUpdate
builder.
+
+A Python function used to print the command lines as they are executed
+(assuming command printing is not disabled by the
+-q
+or
+-s
+options or their equivalents).
+The function should take four arguments:
+s
,
+the command being executed (a string),
+target
,
+the target being built (file node, list, or string name(s)),
+source
,
+the source(s) used (file node, list, or string name(s)), and
+env
,
+the environment being used.
+
+The function must do the printing itself. The default implementation, +used if this variable is not set or is None, is: +
+def print_cmd_line(s, target, source, env): + sys.stdout.write(s + "\n") +
+Here's an example of a more interesting function: +
+def print_cmd_line(s, target, source, env): + sys.stdout.write("Building %s -> %s...\n" % + (' and '.join([str(x) for x in source]), + ' and '.join([str(x) for x in target]))) +env=Environment(PRINT_CMD_LINE_FUNC=print_cmd_line) +env.Program('foo', 'foo.c') +
+This just prints "Building targetname
from sourcename
..." instead
+of the actual commands.
+Such a function could also log the actual commands to a log file,
+for example.
+
+TODO +
+The prefix used for executable file names. +
+The suffix used for executable file names. +
+The command line used to convert TeX DVI files into a PostScript file. +
+The string displayed when a TeX DVI file
+is converted into a PostScript file.
+If this is not set, then $PSCOM
(the command line) is displayed.
+
+The prefix used for PostScript file names. +
+The prefix used for PostScript file names. +
+Turn off scanning for mocable files. Use the Moc Builder to explicitly +specify files to run moc on. +
+The path where the qt binaries are installed.
+The default value is '$QTDIR
/bin'.
+
+The path where the qt header files are installed.
+The default value is '$QTDIR
/include'.
+Note: If you set this variable to None,
+the tool won't change the $CPPPATH
+construction variable.
+
+Prints lots of debugging information while scanning for moc files. +
+Default value is 'qt'. You may want to set this to 'qt-mt'. Note: If you set
+this variable to None, the tool won't change the $LIBS
variable.
+
+The path where the qt libraries are installed.
+The default value is '$QTDIR
/lib'.
+Note: If you set this variable to None,
+the tool won't change the $LIBPATH
+construction variable.
+
+Default value is '$QT_BINPATH
/moc'.
+
+Default value is ''. Prefix for moc output files, when source is a cxx file. +
+Default value is '.moc'. Suffix for moc output files, when source is a cxx +file. +
+Command to generate a moc file from a cpp file. +
+The string displayed when generating a moc file from a cpp file.
+If this is not set, then $QT_MOCFROMCXXCOM
(the command line) is displayed.
+
+Default value is '-i'. These flags are passed to moc, when moccing a +C++ file. +
+Command to generate a moc file from a header. +
+The string displayed when generating a moc file from a cpp file.
+If this is not set, then $QT_MOCFROMHCOM
(the command line) is displayed.
+
+Default value is ''. These flags are passed to moc, when moccing a header +file. +
+Default value is 'moc_'. Prefix for moc output files, when source is a header. +
+Default value is '$CXXFILESUFFIX
'. Suffix for moc output files, when source is
+a header.
+
+Default value is '$QT_BINPATH
/uic'.
+
+Command to generate header files from .ui files. +
+The string displayed when generating header files from .ui files.
+If this is not set, then $QT_UICCOM
(the command line) is displayed.
+
+Default value is ''. These flags are passed to uic, when creating a a h +file from a .ui file. +
+Default value is ''. Prefix for uic generated header files. +
+Default value is '.h'. Suffix for uic generated header files. +
+Default value is ''. These flags are passed to uic, when creating a cxx +file from a .ui file. +
+Default value is 'uic_'. Prefix for uic generated implementation files. +
+Default value is '$CXXFILESUFFIX
'. Suffix for uic generated implementation
+files.
+
+Default value is '.ui'. Suffix of designer input files. +
+The qt tool tries to take this from os.environ.
+It also initializes all QT_*
+construction variables listed below.
+(Note that all paths are constructed
+with python's os.path.join() method,
+but are listed here with the '/' separator
+for easier reading.)
+In addition, the construction environment
+variables $CPPPATH
,
+$LIBPATH
and
+$LIBS
may be modified
+and the variables
+$PROGEMITTER
, $SHLIBEMITTER
and $LIBEMITTER
+are modified. Because the build-performance is affected when using this tool,
+you have to explicitly specify it at Environment creation:
+
+Environment(tools=['default','qt']) +
+The qt tool supports the following operations: +
+Automatic moc file generation from header files.
+You do not have to specify moc files explicitly, the tool does it for you.
+However, there are a few preconditions to do so: Your header file must have
+the same filebase as your implementation file and must stay in the same
+directory. It must have one of the suffixes .h, .hpp, .H, .hxx, .hh. You
+can turn off automatic moc file generation by setting QT_AUTOSCAN to 0.
+See also the corresponding
+Moc
()
+builder method.
+
+Automatic moc file generation from cxx files.
+As stated in the qt documentation, include the moc file at the end of
+the cxx file. Note that you have to include the file, which is generated
+by the transformation ${QT_MOCCXXPREFIX}<basename>${QT_MOCCXXSUFFIX}, by default
+<basename>.moc. A warning is generated after building the moc file, if you
+do not include the correct file. If you are using VariantDir, you may
+need to specify duplicate=1. You can turn off automatic moc file generation
+by setting QT_AUTOSCAN to 0. See also the corresponding
+Moc
+builder method.
+
+Automatic handling of .ui files.
+The implementation files generated from .ui files are handled much the same
+as yacc or lex files. Each .ui file given as a source of Program, Library or
+SharedLibrary will generate three files, the declaration file, the
+implementation file and a moc file. Because there are also generated headers,
+you may need to specify duplicate=1 in calls to VariantDir.
+See also the corresponding
+Uic
+builder method.
+
+The archive indexer. +
+The command line used to index a static library archive. +
+The string displayed when a static library archive is indexed.
+If this is not set, then $RANLIBCOM
(the command line) is displayed.
+
+env = Environment(RANLIBCOMSTR = "Indexing $TARGET") +
+General options passed to the archive indexer. +
+The resource compiler used to build +a Microsoft Visual C++ resource file. +
+The command line used to build +a Microsoft Visual C++ resource file. +
+The string displayed when invoking the resource compiler
+to build a Microsoft Visual C++ resource file.
+If this is not set, then $RCCOM
(the command line) is displayed.
+
+The flags passed to the resource compiler by the RES builder. +
+An automatically-generated construction variable
+containing the command-line options
+for specifying directories to be searched
+by the resource compiler.
+The value of $RCINCFLAGS
is created
+by respectively prepending and appending
+$RCINCPREFIX
and $RCINCSUFFIX
+to the beginning and end
+of each directory in $CPPPATH
.
+
+The prefix (flag) used to specify an include directory
+on the resource compiler command line.
+This will be prepended to the beginning of each directory
+in the $CPPPATH
construction variable
+when the $RCINCFLAGS
variable is expanded.
+
+The suffix used to specify an include directory
+on the resource compiler command line.
+This will be appended to the end of each directory
+in the $CPPPATH
construction variable
+when the $RCINCFLAGS
variable is expanded.
+
+A function that converts a string into a list of Dir instances by +searching the repositories. +
+The program used on Windows systems
+to register a newly-built DLL library
+whenever the SharedLibrary
builder
+is passed a keyword argument of register=1
.
+
+The command line used on Windows systems
+to register a newly-built DLL library
+whenever the SharedLibrary
builder
+is passed a keyword argument of register=1
.
+
+The string displayed when registering a newly-built DLL file.
+If this is not set, then $REGSVRCOM
(the command line) is displayed.
+
+Flags passed to the DLL registration program
+on Windows systems when a newly-built DLL library is registered.
+By default,
+this includes the /s
+that prevents dialog boxes from popping up
+and requiring user attention.
+
+The Java RMI stub compiler. +
+The command line used to compile stub
+and skeleton class files
+from Java classes that contain RMI implementations.
+Any options specified in the $RMICFLAGS
construction variable
+are included on this command line.
+
+The string displayed when compiling
+stub and skeleton class files
+from Java classes that contain RMI implementations.
+If this is not set, then $RMICCOM
(the command line) is displayed.
+
+env = Environment(RMICCOMSTR = "Generating stub/skeleton class files $TARGETS from $SOURCES") +
+General options passed to the Java RMI stub compiler. +
+An automatically-generated construction variable
+containing the rpath flags to be used when linking
+a program with shared libraries.
+The value of $_RPATH
is created
+by respectively prepending $RPATHPREFIX
and appending $RPATHSUFFIX
+to the beginning and end
+of each directory in $RPATH
.
+
+A list of paths to search for shared libraries when running programs.
+Currently only used in the GNU (gnulink),
+IRIX (sgilink) and Sun (sunlink) linkers.
+Ignored on platforms and toolchains that don't support it.
+Note that the paths added to RPATH
+are not transformed by
+scons
+in any way: if you want an absolute
+path, you must make it absolute yourself.
+
+The prefix used to specify a directory to be searched for
+shared libraries when running programs.
+This will be prepended to the beginning of each directory
+in the $RPATH
construction variable
+when the $_RPATH
variable is automatically generated.
+
+The suffix used to specify a directory to be searched for
+shared libraries when running programs.
+This will be appended to the end of each directory
+in the $RPATH
construction variable
+when the $_RPATH
variable is automatically generated.
+
+The RPC protocol compiler. +
+Options passed to the RPC protocol compiler
+when generating client side stubs.
+These are in addition to any flags specified in the
+$RPCGENFLAGS
+construction variable.
+
+General options passed to the RPC protocol compiler. +
+Options passed to the RPC protocol compiler
+when generating a header file.
+These are in addition to any flags specified in the
+$RPCGENFLAGS
+construction variable.
+
+Options passed to the RPC protocol compiler
+when generating server side stubs.
+These are in addition to any flags specified in the
+$RPCGENFLAGS
+construction variable.
+
+Options passed to the RPC protocol compiler
+when generating XDR routines.
+These are in addition to any flags specified in the
+$RPCGENFLAGS
+construction variable.
+
+A list of the available implicit dependency scanners. +New file scanners may be added by +appending to this list, +although the more flexible approach +is to associate scanners +with a specific Builder. +See the sections "Builder Objects" +and "Scanner Objects," +below, for more information. +
The
+(optional) path to the SCons library directory, initialized from the external
+environment. If set, this is used to construct a shorter and more efficient
+search path in the $MSVSSCONS
command line executed from Microsoft
+Visual Studio project files.
+The C compiler used for generating shared-library objects. +
+The command line used to compile a C source file
+to a shared-library object file.
+Any options specified in the $SHCFLAGS
,
+$SHCCFLAGS
and
+$CPPFLAGS
construction variables
+are included on this command line.
+
+The string displayed when a C source file
+is compiled to a shared object file.
+If this is not set, then $SHCCCOM
(the command line) is displayed.
+
+env = Environment(SHCCCOMSTR = "Compiling shared object $TARGET") +
+Options that are passed to the C and C++ compilers +to generate shared-library objects. +
+Options that are passed to the C compiler (only; not C++) +to generate shared-library objects. +
+The C++ compiler used for generating shared-library objects. +
+The command line used to compile a C++ source file
+to a shared-library object file.
+Any options specified in the $SHCXXFLAGS
and
+$CPPFLAGS
construction variables
+are included on this command line.
+
+The string displayed when a C++ source file
+is compiled to a shared object file.
+If this is not set, then $SHCXXCOM
(the command line) is displayed.
+
+env = Environment(SHCXXCOMSTR = "Compiling shared object $TARGET") +
+Options that are passed to the C++ compiler +to generate shared-library objects. +
+ The name of the compiler to use when compiling D source + destined to be in a shared objects. +
+ The name of the compiler to use when compiling D source + destined to be in a shared objects. +
+ The name of the compiler to use when compiling D source + destined to be in a shared objects. +
+ The command line to use when compiling code to be part of shared objects. +
+ The command line to use when compiling code to be part of shared objects. +
+ The command line to use when compiling code to be part of shared objects. +
+ SHDLIBVERSION. +
+ SHDLIBVERSIONFLAGS. +
+ The linker to use when creating shared objects for code bases + include D sources. +
+ The linker to use when creating shared objects for code bases + include D sources. +
+ The linker to use when creating shared objects for code bases + include D sources. +
+ The command line to use when generating shared objects. +
+ The command line to use when generating shared objects. +
+ The command line to use when generating shared objects. +
+ The list of flags to use when generating a shared object. +
+ The list of flags to use when generating a shared object. +
+ The list of flags to use when generating a shared object. +
+A string naming the shell program that will be passed to the
+$SPAWN
+function.
+See the
+$SPAWN
+construction variable for more information.
+
+The Fortran 03 compiler used for generating shared-library objects.
+You should normally set the $SHFORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $SHF03
if you need to use a specific compiler
+or compiler version for Fortran 03 files.
+
+The command line used to compile a Fortran 03 source file
+to a shared-library object file.
+You only need to set $SHF03COM
if you need to use a specific
+command line for Fortran 03 files.
+You should normally set the $SHFORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 03 source file
+is compiled to a shared-library object file.
+If this is not set, then $SHF03COM
or $SHFORTRANCOM
+(the command line) is displayed.
+
+Options that are passed to the Fortran 03 compiler
+to generated shared-library objects.
+You only need to set $SHF03FLAGS
if you need to define specific
+user options for Fortran 03 files.
+You should normally set the $SHFORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+The command line used to compile a Fortran 03 source file to a
+shared-library object file
+after first running the file through the C preprocessor.
+Any options specified in the $SHF03FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $SHF03PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 03 files.
+You should normally set the $SHFORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 03 source file
+is compiled to a shared-library object file
+after first running the file through the C preprocessor.
+If this is not set, then $SHF03PPCOM
or $SHFORTRANPPCOM
+(the command line) is displayed.
+
+The Fortran 08 compiler used for generating shared-library objects.
+You should normally set the $SHFORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $SHF08
if you need to use a specific compiler
+or compiler version for Fortran 08 files.
+
+The command line used to compile a Fortran 08 source file
+to a shared-library object file.
+You only need to set $SHF08COM
if you need to use a specific
+command line for Fortran 08 files.
+You should normally set the $SHFORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 08 source file
+is compiled to a shared-library object file.
+If this is not set, then $SHF08COM
or $SHFORTRANCOM
+(the command line) is displayed.
+
+Options that are passed to the Fortran 08 compiler
+to generated shared-library objects.
+You only need to set $SHF08FLAGS
if you need to define specific
+user options for Fortran 08 files.
+You should normally set the $SHFORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+The command line used to compile a Fortran 08 source file to a
+shared-library object file
+after first running the file through the C preprocessor.
+Any options specified in the $SHF08FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $SHF08PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 08 files.
+You should normally set the $SHFORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 08 source file
+is compiled to a shared-library object file
+after first running the file through the C preprocessor.
+If this is not set, then $SHF08PPCOM
or $SHFORTRANPPCOM
+(the command line) is displayed.
+
+The Fortran 77 compiler used for generating shared-library objects.
+You should normally set the $SHFORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $SHF77
if you need to use a specific compiler
+or compiler version for Fortran 77 files.
+
+The command line used to compile a Fortran 77 source file
+to a shared-library object file.
+You only need to set $SHF77COM
if you need to use a specific
+command line for Fortran 77 files.
+You should normally set the $SHFORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 77 source file
+is compiled to a shared-library object file.
+If this is not set, then $SHF77COM
or $SHFORTRANCOM
+(the command line) is displayed.
+
+Options that are passed to the Fortran 77 compiler
+to generated shared-library objects.
+You only need to set $SHF77FLAGS
if you need to define specific
+user options for Fortran 77 files.
+You should normally set the $SHFORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+The command line used to compile a Fortran 77 source file to a
+shared-library object file
+after first running the file through the C preprocessor.
+Any options specified in the $SHF77FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $SHF77PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 77 files.
+You should normally set the $SHFORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 77 source file
+is compiled to a shared-library object file
+after first running the file through the C preprocessor.
+If this is not set, then $SHF77PPCOM
or $SHFORTRANPPCOM
+(the command line) is displayed.
+
+The Fortran 90 compiler used for generating shared-library objects.
+You should normally set the $SHFORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $SHF90
if you need to use a specific compiler
+or compiler version for Fortran 90 files.
+
+The command line used to compile a Fortran 90 source file
+to a shared-library object file.
+You only need to set $SHF90COM
if you need to use a specific
+command line for Fortran 90 files.
+You should normally set the $SHFORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 90 source file
+is compiled to a shared-library object file.
+If this is not set, then $SHF90COM
or $SHFORTRANCOM
+(the command line) is displayed.
+
+Options that are passed to the Fortran 90 compiler
+to generated shared-library objects.
+You only need to set $SHF90FLAGS
if you need to define specific
+user options for Fortran 90 files.
+You should normally set the $SHFORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+The command line used to compile a Fortran 90 source file to a
+shared-library object file
+after first running the file through the C preprocessor.
+Any options specified in the $SHF90FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $SHF90PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 90 files.
+You should normally set the $SHFORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 90 source file
+is compiled to a shared-library object file
+after first running the file through the C preprocessor.
+If this is not set, then $SHF90PPCOM
or $SHFORTRANPPCOM
+(the command line) is displayed.
+
+The Fortran 95 compiler used for generating shared-library objects.
+You should normally set the $SHFORTRAN
variable,
+which specifies the default Fortran compiler
+for all Fortran versions.
+You only need to set $SHF95
if you need to use a specific compiler
+or compiler version for Fortran 95 files.
+
+The command line used to compile a Fortran 95 source file
+to a shared-library object file.
+You only need to set $SHF95COM
if you need to use a specific
+command line for Fortran 95 files.
+You should normally set the $SHFORTRANCOM
variable,
+which specifies the default command line
+for all Fortran versions.
+
+The string displayed when a Fortran 95 source file
+is compiled to a shared-library object file.
+If this is not set, then $SHF95COM
or $SHFORTRANCOM
+(the command line) is displayed.
+
+Options that are passed to the Fortran 95 compiler
+to generated shared-library objects.
+You only need to set $SHF95FLAGS
if you need to define specific
+user options for Fortran 95 files.
+You should normally set the $SHFORTRANFLAGS
variable,
+which specifies the user-specified options
+passed to the default Fortran compiler
+for all Fortran versions.
+
+The command line used to compile a Fortran 95 source file to a
+shared-library object file
+after first running the file through the C preprocessor.
+Any options specified in the $SHF95FLAGS
and $CPPFLAGS
construction variables
+are included on this command line.
+You only need to set $SHF95PPCOM
if you need to use a specific
+C-preprocessor command line for Fortran 95 files.
+You should normally set the $SHFORTRANPPCOM
variable,
+which specifies the default C-preprocessor command line
+for all Fortran versions.
+
+The string displayed when a Fortran 95 source file
+is compiled to a shared-library object file
+after first running the file through the C preprocessor.
+If this is not set, then $SHF95PPCOM
or $SHFORTRANPPCOM
+(the command line) is displayed.
+
+The default Fortran compiler used for generating shared-library objects. +
+The command line used to compile a Fortran source file +to a shared-library object file. +
+The string displayed when a Fortran source file
+is compiled to a shared-library object file.
+If this is not set, then $SHFORTRANCOM
+(the command line) is displayed.
+
+Options that are passed to the Fortran compiler +to generate shared-library objects. +
+The command line used to compile a Fortran source file to a
+shared-library object file
+after first running the file through the C preprocessor.
+Any options specified
+in the $SHFORTRANFLAGS
and
+$CPPFLAGS
construction variables
+are included on this command line.
+
+The string displayed when a Fortran source file
+is compiled to a shared-library object file
+after first running the file through the C preprocessor.
+If this is not set, then $SHFORTRANPPCOM
+(the command line) is displayed.
+
+TODO +
+Instructs the SharedLibrary
builder to not create symlinks for versioned
+shared libraries.
+
+The prefix used for shared library file names. +
+A macro that automatically generates shared library's SONAME based on $TARGET,
+$SHLIBVERSION and $SHLIBSUFFIX. Used by SharedLibrary
builder when
+the linker tool supports SONAME (e.g. gnulink
).
+
+The suffix used for shared library file names. +
+When this construction variable is defined, a versioned shared library
+is created by SharedLibrary
builder. This activates the
+$_SHLIBVERSIONFLAGS
and thus modifies the $SHLINKCOM
as
+required, adds the version number to the library name, and creates the symlinks
+that are needed. $SHLIBVERSION
versions should exist as alpha-numeric,
+decimal-delimited values as defined by the regular expression "\w+[\.\w+]*".
+Example $SHLIBVERSION
values include '1', '1.2.3', and '1.2.gitaa412c8b'.
+
+Extra flags added to $SHLINKCOM
when building versioned
+SharedLibrary
. These flags are only used when $SHLIBVERSION
is
+set.
+
+This macro automatically introduces extra flags to $SHLINKCOM
when
+building versioned SharedLibrary
(that is when $SHLIBVERSION
+is set). _SHLIBVERSIONFLAGS
usually adds $SHLIBVERSIONFLAGS
+and some extra dynamically generated options (such as
+-Wl,-soname=$_SHLIBSONAME
. It is unused by "plain"
+(unversioned) shared libraries.
+
+The linker for programs that use shared libraries. +
+The command line used to link programs using shared libraries. +
+The string displayed when programs using shared libraries are linked.
+If this is not set, then $SHLINKCOM
(the command line) is displayed.
+
+env = Environment(SHLINKCOMSTR = "Linking shared $TARGET") +
+General user options passed to the linker for programs using shared libraries.
+Note that this variable should
+not
+contain
+-l
+(or similar) options for linking with the libraries listed in $LIBS
,
+nor
+-L
+(or similar) include search path options
+that scons generates automatically from $LIBPATH
.
+See
+$_LIBFLAGS
+above,
+for the variable that expands to library-link options,
+and
+$_LIBDIRFLAGS
+above,
+for the variable that expands to library search path options.
+
+The prefix used for shared object file names. +
+The suffix used for shared object file names. +
+Variable used to hard-code SONAME for versioned shared library/loadable module. +
+env.SharedLibrary('test', 'test.c', SHLIBVERSION='0.1.2', SONAME='libtest.so.2') +
+The variable is used, for example, by gnulink
linker tool.
+
+A reserved variable name +that may not be set or used in a construction environment. +(See "Variable Substitution," below.) +
+The URL
+(web address)
+of the location from which the project was retrieved.
+This is used to fill in the
+Source:
+field in the controlling information for Ipkg and RPM packages.
+
+A reserved variable name +that may not be set or used in a construction environment. +(See "Variable Substitution," below.) +
+A command interpreter function that will be called to execute command line +strings. The function must expect the following arguments: +
+def spawn(shell, escape, cmd, args, env): +
+sh
+is a string naming the shell program to use.
+escape
+is a function that can be called to escape shell special characters in
+the command line.
+cmd
+is the path to the command to be executed.
+args
+is the arguments to the command.
+env
+is a dictionary of the environment variables
+in which the command should be executed.
+
+ When this variable is true, static objects and shared objects are assumed to be the same; that is, SCons does not check for linking static objects into a shared library. +
+The dictionary used by the Substfile
or Textfile
builders
+for substitution values.
+It can be anything acceptable to the dict() constructor,
+so in addition to a dictionary,
+lists of tuples are also acceptable.
+
+The prefix used for Substfile
file names,
+the null string by default.
+
+The suffix used for Substfile
file names,
+the null string by default.
+
+A short summary of what the project is about.
+This is used to fill in the
+Summary:
+field in the controlling information for Ipkg and RPM packages,
+and as the
+Description:
+field in MSI packages.
+
+The scripting language wrapper and interface generator. +
+The suffix that will be used for intermediate C
+source files generated by
+the scripting language wrapper and interface generator.
+The default value is
+_wrap
$CFILESUFFIX
.
+By default, this value is used whenever the
+-c++
+option is
+not
+specified as part of the
+$SWIGFLAGS
+construction variable.
+
+The command line used to call +the scripting language wrapper and interface generator. +
+The string displayed when calling
+the scripting language wrapper and interface generator.
+If this is not set, then $SWIGCOM
(the command line) is displayed.
+
+The suffix that will be used for intermediate C++
+source files generated by
+the scripting language wrapper and interface generator.
+The default value is
+_wrap
$CFILESUFFIX
.
+By default, this value is used whenever the
+-c++
+option is specified as part of the
+$SWIGFLAGS
+construction variable.
+
+The suffix that will be used for intermediate C++ header
+files generated by the scripting language wrapper and interface generator.
+These are only generated for C++ code when the SWIG 'directors' feature is
+turned on.
+The default value is
+_wrap.h
.
+
+General options passed to
+the scripting language wrapper and interface generator.
+This is where you should set
+-python
,
+-perl5
,
+-tcl
,
+or whatever other options you want to specify to SWIG.
+If you set the
+-c++
+option in this variable,
+scons
+will, by default,
+generate a C++ intermediate source file
+with the extension that is specified as the
+$CXXFILESUFFIX
+variable.
+
+An automatically-generated construction variable
+containing the SWIG command-line options
+for specifying directories to be searched for included files.
+The value of $_SWIGINCFLAGS
is created
+by respectively prepending and appending
+$SWIGINCPREFIX
and $SWIGINCSUFFIX
+to the beginning and end
+of each directory in $SWIGPATH
.
+
+The prefix used to specify an include directory on the SWIG command line.
+This will be prepended to the beginning of each directory
+in the $SWIGPATH
construction variable
+when the $_SWIGINCFLAGS
variable is automatically generated.
+
+The suffix used to specify an include directory on the SWIG command line.
+This will be appended to the end of each directory
+in the $SWIGPATH
construction variable
+when the $_SWIGINCFLAGS
variable is automatically generated.
+
+Specifies the output directory in which
+the scripting language wrapper and interface generator
+should place generated language-specific files.
+This will be used by SCons to identify
+the files that will be generated by the swig call,
+and translated into the
+swig -outdir
option on the command line.
+
+The list of directories that the scripting language wrapper +and interface generate will search for included files. +The SWIG implicit dependency scanner will search these +directories for include files. The default value is an empty list. +
+Don't explicitly put include directory
+arguments in SWIGFLAGS;
+the result will be non-portable
+and the directories will not be searched by the dependency scanner.
+Note: directory names in SWIGPATH will be looked-up relative to the SConscript
+directory when they are used in a command.
+To force
+scons
+to look-up a directory relative to the root of the source tree use #:
+
+env = Environment(SWIGPATH='#/include') +
+The directory look-up can also be forced using the
+Dir
()
+function:
+
+include = Dir('include') +env = Environment(SWIGPATH=include) +
+The directory list will be added to command lines
+through the automatically-generated
+$_SWIGINCFLAGS
+construction variable,
+which is constructed by
+respectively prepending and appending the values of the
+$SWIGINCPREFIX
and $SWIGINCSUFFIX
+construction variables
+to the beginning and end
+of each directory in $SWIGPATH
.
+Any command lines you define that need
+the SWIGPATH directory list should
+include $_SWIGINCFLAGS
:
+
+env = Environment(SWIGCOM="my_swig -o $TARGET $_SWIGINCFLAGS $SOURCES") +
+The version number of the SWIG tool. +
+The tar archiver. +
+The command line used to call the tar archiver. +
+The string displayed when archiving files
+using the tar archiver.
+If this is not set, then $TARCOM
(the command line) is displayed.
+
+env = Environment(TARCOMSTR = "Archiving $TARGET") +
+General options passed to the tar archiver. +
+A reserved variable name +that may not be set or used in a construction environment. +(See "Variable Substitution," below.) +
+ The name of the target hardware architecture for the compiled objects + created by this Environment. + This defaults to the value of HOST_ARCH, and the user can override it. + Currently only set for Win32. +
+Sets the target architecture for Visual Studio compiler (i.e. the arch
+of the binaries generated by the compiler). If not set, default to
+$HOST_ARCH
, or, if that is unset, to the architecture of the
+running machine's OS (note that the python build or architecture has no
+effect).
+This variable must be passed as an argument to the Environment()
+constructor; setting it later has no effect.
+This is currently only used on Windows, but in the future it will be
+used on other OSes as well.
+
+Valid values for Windows are
+x86
,
+i386
+(for 32 bits);
+amd64
,
+emt64
,
+x86_64
+(for 64 bits);
+and ia64
(Itanium).
+For example, if you want to compile 64-bit binaries, you would set
+TARGET_ARCH='x86_64'
in your SCons environment.
+
+ The name of the target operating system for the compiled objects + created by this Environment. + This defaults to the value of HOST_OS, and the user can override it. + Currently only set for Win32. +
+A reserved variable name +that may not be set or used in a construction environment. +(See "Variable Substitution," below.) +
+The suffix used for tar file names. +
+The prefix for a temporary file used +to execute lines longer than $MAXLINELENGTH. +The default is '@'. +This may be set for toolchains that use other values, +such as '-@' for the diab compiler +or '-via' for ARM toolchain. +
+The TeX formatter and typesetter. +
+The command line used to call the TeX formatter and typesetter. +
+The string displayed when calling
+the TeX formatter and typesetter.
+If this is not set, then $TEXCOM
(the command line) is displayed.
+
+env = Environment(TEXCOMSTR = "Building $TARGET from TeX input $SOURCES") +
+General options passed to the TeX formatter and typesetter. +
+List of directories that the LaTeX program will search +for include directories. +The LaTeX implicit dependency scanner will search these +directories for \include and \import files. +
+The prefix used for Textfile
file names,
+the null string by default.
+
+The suffix used for Textfile
file names;
+.txt
by default.
+
+A list of the names of the Tool specifications +that are part of this construction environment. +
+A reserved variable name +that may not be set or used in a construction environment. +(See "Variable Substitution," below.) +
+A reserved variable name +that may not be set or used in a construction environment. +(See "Variable Substitution," below.) +
+The person or organization who supply the packaged software.
+This is used to fill in the
+Vendor:
+field in the controlling information for RPM packages,
+and the
+Manufacturer:
+field in the controlling information for MSI packages.
+
+The version of the project, specified as a string. +
+A deprecated synonym for $WINDOWS_INSERT_DEF
.
+
+A deprecated synonym for $WINDOWSDEFPREFIX
.
+
+A deprecated synonym for $WINDOWSDEFSUFFIX
.
+
+A deprecated synonym for $WINDOWSEXPSUFFIX
.
+
+A deprecated synonym for $WINDOWSEXPSUFFIX
.
+
+Set this variable to True or 1 to embed the compiler-generated manifest
+(normally ${TARGET}.manifest
)
+into all Windows exes and DLLs built with this environment,
+as a resource during their link step.
+This is done using $MT
and $MTEXECOM
and $MTSHLIBCOM
.
+
+When this is set to true,
+a library build of a Windows shared library
+(.dll
file)
+will also build a corresponding .def
file
+at the same time,
+if a .def
file
+is not already listed as a build target.
+The default is 0 (do not build a .def
file).
+
+When this is set to true,
+scons
+will be aware of the
+.manifest
+files generated by Microsoft Visua C/C++ 8.
+
+The prefix used for Windows .def
file names.
+
+The suffix used for Windows .def
file names.
+
+The prefix used for Windows .exp
file names.
+
+The suffix used for Windows .exp
file names.
+
+The prefix used for executable program .manifest
files
+generated by Microsoft Visual C/C++.
+
+The suffix used for executable program .manifest
files
+generated by Microsoft Visual C/C++.
+
+The prefix used for shared library .manifest
files
+generated by Microsoft Visual C/C++.
+
+The suffix used for shared library .manifest
files
+generated by Microsoft Visual C/C++.
+
+This is used to fill in the
+Depends:
+field in the controlling information for Ipkg packages.
+
+This is used to fill in the
+Description:
+field in the controlling information for Ipkg packages.
+The default value is
+$SUMMARY\n$DESCRIPTION
+
+This is used to fill in the
+Maintainer:
+field in the controlling information for Ipkg packages.
+
+This is used to fill in the
+Priority:
+field in the controlling information for Ipkg packages.
+
+This is used to fill in the
+Section:
+field in the controlling information for Ipkg packages.
+
+This is used to fill in the
+Language:
+attribute in the controlling information for MSI packages.
+
+The text of the software license in RTF format. +Carriage return characters will be +replaced with the RTF equivalent \\par. +
+TODO +
+This is used to fill in the
+AutoReqProv:
+field in the RPM
+.spec
file.
+
+internal, but overridable +
+This is used to fill in the
+BuildRequires:
+field in the RPM
+.spec
file.
+Note this should only be used on a host managed by rpm as the dependencies will not be resolvable at build time otherwise.
+
+internal, but overridable +
+internal, but overridable +
+This is used to fill in the
+Conflicts:
+field in the RPM
+.spec
file.
+
+This value is used as the default attributes
+for the files in the RPM package.
+The default value is
+(-,root,root)
.
+
+This is used to fill in the
+Distribution:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+Epoch:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+ExcludeArch:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+ExclusiveArch:
+field in the RPM
+.spec
file.
+
+A list used to supply extra defintions or flags
+to be added to the RPM .spec
file.
+Each item is added as-is with a carriage return appended.
+This is useful if some specific RPM feature not otherwise
+anticipated by SCons needs to be turned on or off.
+Note if this variable is omitted, SCons will by
+default supply the value
+'%global debug_package %{nil}'
+to disable debug package generation.
+To enable debug package generation, include this
+variable set either to None, or to a custom
+list that does not include the default line.
+Added in version 3.1.
+
+env.Package( + NAME = 'foo', +... + X_RPM_EXTRADEFS = [ + '%define _unpackaged_files_terminate_build 0' + '%define _missing_doc_files_terminate_build 0' + ], +... ) +
+This is used to fill in the
+Group:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+Group(lang):
+field in the RPM
+.spec
file.
+Note that
+lang
+is not literal
+and should be replaced by
+the appropriate language code.
+
+This is used to fill in the
+Icon:
+field in the RPM
+.spec
file.
+
+internal, but overridable +
+This is used to fill in the
+Packager:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+%post:
+section in the RPM
+.spec
file.
+
+This is used to fill in the
+%postun:
+section in the RPM
+.spec
file.
+
+This is used to fill in the
+Prefix:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+%pre:
+section in the RPM
+.spec
file.
+
+internal, but overridable +
+This is used to fill in the
+%preun:
+section in the RPM
+.spec
file.
+
+This is used to fill in the
+Provides:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+Requires:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+Serial:
+field in the RPM
+.spec
file.
+
+This is used to fill in the
+Url:
+field in the RPM
+.spec
file.
+
+Path to xgettext(1) program (found via
+Detect()
).
+See xgettext
tool and POTUpdate
builder.
+
+Complete xgettext command line.
+See xgettext
tool and POTUpdate
builder.
+
+A string that is shown when xgettext(1) command is invoked
+(default: ''
, which means "print $XGETTEXTCOM
").
+See xgettext
tool and POTUpdate
builder.
+
+Internal "macro". Generates xgettext domain name
+form source and target (default: '${TARGET.filebase}'
).
+
+Additional flags to xgettext(1).
+See xgettext
tool and POTUpdate
builder.
+
+Name of file containing list of xgettext(1)'s source
+files. Autotools' users know this as POTFILES.in
so they
+will in most cases set XGETTEXTFROM="POTFILES.in"
here.
+The $XGETTEXTFROM
files have same syntax and semantics as the well known
+GNU POTFILES.in
.
+See xgettext
tool and POTUpdate
builder.
+
+Internal "macro". Genrates list of -D<dir>
flags
+from the $XGETTEXTPATH
list.
+
+This flag is used to add single $XGETTEXTFROM
file to
+xgettext(1)'s commandline (default:
+'-f'
).
+
+(default: ''
)
+
+List of directories, there xgettext(1) will look for
+source files (default: []
).
+
+This variable works only together with $XGETTEXTFROM
+
+Internal "macro". Generates list of -f<file>
flags
+from $XGETTEXTFROM
.
+
+This flag is used to add single search path to
+xgettext(1)'s commandline (default:
+'-D'
).
+
+(default: ''
)
+
+The parser generator. +
+The command line used to call the parser generator +to generate a source file. +
+The string displayed when generating a source file
+using the parser generator.
+If this is not set, then $YACCCOM
(the command line) is displayed.
+
+env = Environment(YACCCOMSTR = "Yacc'ing $TARGET from $SOURCES") +
+General options passed to the parser generator.
+If $YACCFLAGS
contains a -d
option,
+SCons assumes that the call will also create a .h file
+(if the yacc source file ends in a .y suffix)
+or a .hpp file
+(if the yacc source file ends in a .yy suffix)
+
+The suffix of the C
+header file generated by the parser generator
+when the
+-d
+option is used.
+Note that setting this variable does not cause
+the parser generator to generate a header
+file with the specified suffix,
+it exists to allow you to specify
+what suffix the parser generator will use of its own accord.
+The default value is
+.h
.
+
+The suffix of the C++
+header file generated by the parser generator
+when the
+-d
+option is used.
+Note that setting this variable does not cause
+the parser generator to generate a header
+file with the specified suffix,
+it exists to allow you to specify
+what suffix the parser generator will use of its own accord.
+The default value is
+.hpp
,
+except on Mac OS X,
+where the default is
+${TARGET.suffix}.h
.
+because the default bison parser generator just
+appends .h
+to the name of the generated C++ file.
+
+The suffix of the file
+containing the VCG grammar automaton definition
+when the
+--graph=
+option is used.
+Note that setting this variable does not cause
+the parser generator to generate a VCG
+file with the specified suffix,
+it exists to allow you to specify
+what suffix the parser generator will use of its own accord.
+The default value is
+.vcg
.
+
+The zip compression and file packaging utility. +
+The command line used to call the zip utility, +or the internal Python function used to create a +zip archive. +
+The
+compression
+flag
+from the Python
+zipfile
+module used by the internal Python function
+to control whether the zip archive
+is compressed or not.
+The default value is
+zipfile.ZIP_DEFLATED
,
+which creates a compressed zip archive.
+This value has no effect if the
+zipfile
+module is unavailable.
+
+The string displayed when archiving files
+using the zip utility.
+If this is not set, then $ZIPCOM
+(the command line or internal Python function) is displayed.
+
+env = Environment(ZIPCOMSTR = "Zipping $TARGET") +
+General options passed to the zip utility. +
+An optional zip root directory (default empty). The filenames stored +in the zip file will be relative to this directory, if given. +Otherwise the filenames are relative to the current directory of the +command. +For instance: +
+env = Environment() +env.Zip('foo.zip', 'subdir1/subdir2/file1', ZIPROOT='subdir1') +
+will produce a zip file foo.zip
+containing a file with the name
+subdir2/file1
rather than
+subdir1/subdir2/file1
.
+
+The suffix used for zip file names. +
+ +This appendix contains descriptions of all of the +Builders that are potentially +available "out of the box" in this version of SCons. + +
CFile()
+ ,
+ env.CFile()
+
+Builds a C source file given a lex (.l
)
+or yacc (.y
) input file.
+The suffix specified by the $CFILESUFFIX
construction variable
+(.c
by default)
+is automatically added to the target
+if it is not already present.
+Example:
+
+# builds foo.c +env.CFile(target = 'foo.c', source = 'foo.l') +# builds bar.c +env.CFile(target = 'bar', source = 'bar.y') +
Command()
+ ,
+ env.Command()
+
+The Command
"Builder" is actually implemented
+as a function that looks like a Builder,
+but actually takes an additional argument of the action
+from which the Builder should be made.
+See the Command
function description
+for the calling syntax and details.
+
CXXFile()
+ ,
+ env.CXXFile()
+
+Builds a C++ source file given a lex (.ll
)
+or yacc (.yy
)
+input file.
+The suffix specified by the $CXXFILESUFFIX
construction variable
+(.cc
by default)
+is automatically added to the target
+if it is not already present.
+Example:
+
+# builds foo.cc +env.CXXFile(target = 'foo.cc', source = 'foo.ll') +# builds bar.cc +env.CXXFile(target = 'bar', source = 'bar.yy') +
DocbookEpub()
+ ,
+ env.DocbookEpub()
+ +A pseudo-Builder, providing a Docbook toolchain for EPUB output. +
env = Environment(tools=['docbook']) +env.DocbookEpub('manual.epub', 'manual.xml') +
+or simply +
env = Environment(tools=['docbook']) +env.DocbookEpub('manual') +
DocbookHtml()
+ ,
+ env.DocbookHtml()
+ +A pseudo-Builder, providing a Docbook toolchain for HTML output. +
env = Environment(tools=['docbook']) +env.DocbookHtml('manual.html', 'manual.xml') +
+or simply +
env = Environment(tools=['docbook']) +env.DocbookHtml('manual') +
DocbookHtmlChunked()
+ ,
+ env.DocbookHtmlChunked()
+
+A pseudo-Builder, providing a Docbook toolchain for chunked HTML output.
+It supports the base.dir
parameter. The
+chunkfast.xsl
file (requires "EXSLT") is used as the
+default stylesheet. Basic syntax:
+
env = Environment(tools=['docbook']) +env.DocbookHtmlChunked('manual') +
+where manual.xml
is the input file.
+
If you use the root.filename
+parameter in your own stylesheets you have to specify the new target name.
+This ensures that the dependencies get correct, especially for the cleanup via “scons -c
”:
+
env = Environment(tools=['docbook']) +env.DocbookHtmlChunked('mymanual.html', 'manual', xsl='htmlchunk.xsl') +
Some basic support for the base.dir
is provided. You
+can add the base_dir
keyword to your Builder
+call, and the given prefix gets prepended to all the created filenames:
+
env = Environment(tools=['docbook']) +env.DocbookHtmlChunked('manual', xsl='htmlchunk.xsl', base_dir='output/') +
Make sure that you don't forget the trailing slash for the base folder, else +your files get renamed only! +
DocbookHtmlhelp()
+ ,
+ env.DocbookHtmlhelp()
+ +A pseudo-Builder, providing a Docbook toolchain for HTMLHELP output. +Its basic syntax is: +
env = Environment(tools=['docbook']) +env.DocbookHtmlhelp('manual') +
+where manual.xml
is the input file.
+
If you use the root.filename
+parameter in your own stylesheets you have to specify the new target name.
+This ensures that the dependencies get correct, especially for the cleanup via “scons -c
”:
+
env = Environment(tools=['docbook']) +env.DocbookHtmlhelp('mymanual.html', 'manual', xsl='htmlhelp.xsl') +
Some basic support for the base.dir
parameter
+is provided. You can add the base_dir
keyword to
+your Builder call, and the given prefix gets prepended to all the
+created filenames:
+
env = Environment(tools=['docbook']) +env.DocbookHtmlhelp('manual', xsl='htmlhelp.xsl', base_dir='output/') +
Make sure that you don't forget the trailing slash for the base folder, else +your files get renamed only! +
DocbookMan()
+ ,
+ env.DocbookMan()
+ +A pseudo-Builder, providing a Docbook toolchain for Man page output. +Its basic syntax is: +
env = Environment(tools=['docbook']) +env.DocbookMan('manual') +
+where manual.xml
is the input file. Note, that
+you can specify a target name, but the actual output names are automatically
+set from the refname
entries in your XML source.
+
DocbookPdf()
+ ,
+ env.DocbookPdf()
+ +A pseudo-Builder, providing a Docbook toolchain for PDF output. +
env = Environment(tools=['docbook']) +env.DocbookPdf('manual.pdf', 'manual.xml') +
+or simply +
env = Environment(tools=['docbook']) +env.DocbookPdf('manual') +
DocbookSlidesHtml()
+ ,
+ env.DocbookSlidesHtml()
+ +A pseudo-Builder, providing a Docbook toolchain for HTML slides output. +
env = Environment(tools=['docbook']) +env.DocbookSlidesHtml('manual') +
If you use the titlefoil.html
parameter in
+your own stylesheets you have to give the new target name. This ensures
+that the dependencies get correct, especially for the cleanup via
+“scons -c
”:
+
env = Environment(tools=['docbook']) +env.DocbookSlidesHtml('mymanual.html','manual', xsl='slideshtml.xsl') +
Some basic support for the base.dir
parameter
+is provided. You
+can add the base_dir
keyword to your Builder
+call, and the given prefix gets prepended to all the created filenames:
+
env = Environment(tools=['docbook']) +env.DocbookSlidesHtml('manual', xsl='slideshtml.xsl', base_dir='output/') +
Make sure that you don't forget the trailing slash for the base folder, else +your files get renamed only! +
DocbookSlidesPdf()
+ ,
+ env.DocbookSlidesPdf()
+ +A pseudo-Builder, providing a Docbook toolchain for PDF slides output. +
env = Environment(tools=['docbook']) +env.DocbookSlidesPdf('manual.pdf', 'manual.xml') +
+or simply +
env = Environment(tools=['docbook']) +env.DocbookSlidesPdf('manual') +
DocbookXInclude()
+ ,
+ env.DocbookXInclude()
+ +A pseudo-Builder, for resolving XIncludes in a separate processing step. +
env = Environment(tools=['docbook']) +env.DocbookXInclude('manual_xincluded.xml', 'manual.xml') +
DocbookXslt()
+ ,
+ env.DocbookXslt()
+ +A pseudo-Builder, applying a given XSL transformation to the input file. +
env = Environment(tools=['docbook']) +env.DocbookXslt('manual_transformed.xml', 'manual.xml', xsl='transform.xslt') +
Note, that this builder requires the xsl
parameter
+to be set.
+
DVI()
+ ,
+ env.DVI()
+
+Builds a .dvi
file
+from a .tex
,
+.ltx
or .latex
input file.
+If the source file suffix is .tex
,
+scons
+will examine the contents of the file;
+if the string
+\documentclass
+or
+\documentstyle
+is found, the file is assumed to be a LaTeX file and
+the target is built by invoking the $LATEXCOM
command line;
+otherwise, the $TEXCOM
command line is used.
+If the file is a LaTeX file,
+the
+DVI
+builder method will also examine the contents
+of the
+.aux
+file and invoke the $BIBTEX
command line
+if the string
+bibdata
+is found,
+start $MAKEINDEX
to generate an index if a
+.ind
+file is found
+and will examine the contents
+.log
+file and re-run the $LATEXCOM
command
+if the log file says it is necessary.
+
+The suffix .dvi
+(hard-coded within TeX itself)
+is automatically added to the target
+if it is not already present.
+Examples:
+
+# builds from aaa.tex +env.DVI(target = 'aaa.dvi', source = 'aaa.tex') +# builds bbb.dvi +env.DVI(target = 'bbb', source = 'bbb.ltx') +# builds from ccc.latex +env.DVI(target = 'ccc.dvi', source = 'ccc.latex') +
Gs()
+ ,
+ env.Gs()
+
+A Builder for explicitly calling the gs
executable.
+Depending on the underlying OS, the different names gs
,
+gsos2
and gswin32c
+are tried.
+
env = Environment(tools=['gs']) +env.Gs('cover.jpg','scons-scons.pdf', + GSFLAGS='-dNOPAUSE -dBATCH -sDEVICE=jpeg -dFirstPage=1 -dLastPage=1 -q') + ) +
Install()
+ ,
+ env.Install()
+ +Installs one or more source files or directories +in the specified target, +which must be a directory. +The names of the specified source files or directories +remain the same within the destination directory. The +sources may be given as a string or as a node returned by +a builder. +
+env.Install('/usr/local/bin', source = ['foo', 'bar']) +
InstallAs()
+ ,
+ env.InstallAs()
+ +Installs one or more source files or directories +to specific names, +allowing changing a file or directory name +as part of the installation. +It is an error if the +target +and +source +arguments list different numbers of files or directories. +
+env.InstallAs(target = '/usr/local/bin/foo', + source = 'foo_debug') +env.InstallAs(target = ['../lib/libfoo.a', '../lib/libbar.a'], + source = ['libFOO.a', 'libBAR.a']) +
InstallVersionedLib()
+ ,
+ env.InstallVersionedLib()
+ +Installs a versioned shared library. The symlinks appropriate to the +architecture will be generated based on symlinks of the source library. +
+env.InstallVersionedLib(target = '/usr/local/bin/foo', + source = 'libxyz.1.5.2.so') +
Jar()
+ ,
+ env.Jar()
+
+Builds a Java archive (.jar
) file
+from the specified list of sources.
+Any directories in the source list
+will be searched for .class
files).
+Any .java
files in the source list
+will be compiled to .class
files
+by calling the Java
Builder.
+
+If the $JARCHDIR
value is set, the
+jar
+command will change to the specified directory using the
+-C
+option.
+If $JARCHDIR
is not set explicitly,
+SCons will use the top of any subdirectory tree
+in which Java .class
+were built by the Java
Builder.
+
+If the contents any of the source files begin with the string
+Manifest-Version
,
+the file is assumed to be a manifest
+and is passed to the
+jar
+command with the
+m
+option set.
+
+env.Jar(target = 'foo.jar', source = 'classes') + +env.Jar(target = 'bar.jar', + source = ['bar1.java', 'bar2.java']) +
Java()
+ ,
+ env.Java()
+
+ Builds one or more Java class files.
+ The sources may be any combination of explicit
+ .java
+ files,
+ or directory trees which will be scanned
+ for .java
files.
+
+ SCons will parse each source .java
file
+ to find the classes
+ (including inner classes)
+ defined within that file,
+ and from that figure out the
+ target .class
files that will be created.
+ The class files will be placed underneath
+ the specified target directory.
+
+ SCons will also search each Java file
+ for the Java package name,
+ which it assumes can be found on a line
+ beginning with the string
+ package
+ in the first column;
+ the resulting .class
files
+ will be placed in a directory reflecting
+ the specified package name.
+ For example,
+ the file
+ Foo.java
+ defining a single public
+ Foo
+ class and
+ containing a package name of
+ sub.dir
+ will generate a corresponding
+ sub/dir/Foo.class
+ class file.
+
+ Examples: +
+ env.Java(target = 'classes', source = 'src') + env.Java(target = 'classes', source = ['src1', 'src2']) + env.Java(target = 'classes', source = ['File1.java', 'File2.java']) +
+ Java source files can use the native encoding for the underlying OS.
+ Since SCons compiles in simple ASCII mode by default,
+ the compiler will generate warnings about unmappable characters,
+ which may lead to errors as the file is processed further.
+ In this case, the user must specify the
+ LANG
+ environment variable to tell the compiler what encoding is used.
+ For portibility, it's best if the encoding is hard-coded
+ so that the compile will work if it is done on a system
+ with a different encoding.
+
+ env = Environment() + env['ENV']['LANG'] = 'en_GB.UTF-8' +
JavaH()
+ ,
+ env.JavaH()
+
+Builds C header and source files for
+implementing Java native methods.
+The target can be either a directory
+in which the header files will be written,
+or a header file name which
+will contain all of the definitions.
+The source can be the names of .class
files,
+the names of .java
files
+to be compiled into .class
files
+by calling the Java
builder method,
+or the objects returned from the
+Java
+builder method.
+
+If the construction variable
+$JAVACLASSDIR
+is set, either in the environment
+or in the call to the
+JavaH
+builder method itself,
+then the value of the variable
+will be stripped from the
+beginning of any .class
file names.
+
+Examples: +
+# builds java_native.h +classes = env.Java(target = 'classdir', source = 'src') +env.JavaH(target = 'java_native.h', source = classes) + +# builds include/package_foo.h and include/package_bar.h +env.JavaH(target = 'include', + source = ['package/foo.class', 'package/bar.class']) + +# builds export/foo.h and export/bar.h +env.JavaH(target = 'export', + source = ['classes/foo.class', 'classes/bar.class'], + JAVACLASSDIR = 'classes') +
Library()
+ ,
+ env.Library()
+
+A synonym for the
+StaticLibrary
+builder method.
+
LoadableModule()
+ ,
+ env.LoadableModule()
+
+On most systems,
+this is the same as
+SharedLibrary
.
+On Mac OS X (Darwin) platforms,
+this creates a loadable module bundle.
+
M4()
+ ,
+ env.M4()
+
+Builds an output file from an M4 input file.
+This uses a default $M4FLAGS
value of
+-E
,
+which considers all warnings to be fatal
+and stops on the first warning
+when using the GNU version of m4.
+Example:
+
+env.M4(target = 'foo.c', source = 'foo.c.m4') +
Moc()
+ ,
+ env.Moc()
+
+Builds an output file from a moc input file. Moc input files are either
+header files or cxx files. This builder is only available after using the
+tool 'qt'. See the $QTDIR
variable for more information.
+Example:
+
+env.Moc('foo.h') # generates moc_foo.cc +env.Moc('foo.cpp') # generates foo.moc +
MOFiles()
+ ,
+ env.MOFiles()
+
+This builder belongs to msgfmt
tool. The builder compiles
+PO
files to MO
files.
+
+Example 1.
+Create pl.mo
and en.mo
by compiling
+pl.po
and en.po
:
+
+ # ... + env.MOFiles(['pl', 'en']) +
+Example 2.
+Compile files for languages defined in LINGUAS
file:
+
+ # ... + env.MOFiles(LINGUAS_FILE = 1) +
+Example 3.
+Create pl.mo
and en.mo
by compiling
+pl.po
and en.po
plus files for
+languages defined in LINGUAS
file:
+
+ # ... + env.MOFiles(['pl', 'en'], LINGUAS_FILE = 1) +
+Example 4.
+Compile files for languages defined in LINGUAS
file
+(another version):
+
+ # ... + env['LINGUAS_FILE'] = 1 + env.MOFiles() +
MSVSProject()
+ ,
+ env.MSVSProject()
+ Builds a Microsoft Visual Studio project +file, and by default builds a solution file as well.
This
+builds a Visual Studio project file, based on the version of Visual Studio
+that is configured (either the latest installed version, or the version
+specified by $MSVS_VERSION
in the Environment constructor). For
+Visual Studio 6, it will generate a .dsp
file. For Visual
+Studio 7 (.NET) and later versions, it will generate a
+.vcproj
file.
By default, this also
+generates a solution file for the specified project, a
+.dsw
file for Visual Studio 6 or a
+.sln
file for Visual Studio 7 (.NET). This behavior may
+be disabled by specifying auto_build_solution=0
when you
+call MSVSProject
, in which case you presumably want to build the solution
+file(s) by calling the MSVSSolution
Builder (see below).
+The MSVSProject
builder takes several lists of filenames to be placed into
+the project file. These are currently limited to srcs
,
+incs
, localincs
,
+resources
, and misc
. These are pretty
+self-explanatory, but it should be noted that these lists are added to the
+$SOURCES
construction variable as strings, NOT as SCons File Nodes.
+This is because they represent file names to be added to the project file, not
+the source files used to build the project file.
The above +filename lists are all optional, although at least one must be specified for +the resulting project file to be non-empty.
In addition to the +above lists of values, the following values may be specified: +
The name of the target .dsp
or
+ .vcproj
file. The correct suffix for the version
+ of Visual Studio must be used, but the $MSVSPROJECTSUFFIX
+ construction variable will be defined to the correct value (see
+ example below).
The name of this particular variant. For Visual Studio 7
+ projects, this can also be a list of variant names. These are
+ typically things like "Debug" or "Release", but really can be anything
+ you want. For Visual Studio 7 projects, they may also specify a target
+ platform separated from the variant name by a |
+ (vertical pipe) character: Debug|Xbox
. The default
+ target platform is Win32. Multiple calls to MSVSProject
with
+ different variants are allowed; all variants will be added to the
+ project file with their appropriate build targets and
+ sources.
Additional command line arguments for the different
+ variants. The number of cmdargs
entries must match
+ the number of variant
entries, or be empty (not
+ specified). If you give only one, it will automatically be propagated
+ to all variants.
An optional string, node, or list of strings or nodes (one
+ per build variant), to tell the Visual Studio debugger what output
+ target to use in what build variant. The number of
+ buildtarget
entries must match the number of
+ variant
entries.
The name of the file that Visual Studio 7 and later will
+ run and debug. This appears as the value of the
+ Output
field in the resulting Visual Studio project
+ file. If this is not specified, the default is the same as the
+ specified buildtarget
value.
Note that because SCons always executes its build
+commands from the directory in which the SConstruct
file is located, if you
+generate a project file in a different directory than the SConstruct
+directory, users will not be able to double-click on the file name in
+compilation error messages displayed in the Visual Studio console output
+window. This can be remedied by adding the Visual C/C++ /FC
+compiler option to the $CCFLAGS
variable so that the compiler will
+print the full path name of any files that cause compilation errors.
Example usage:
+barsrcs = ['bar.cpp'] +barincs = ['bar.h'] +barlocalincs = ['StdAfx.h'] +barresources = ['bar.rc','resource.h'] +barmisc = ['bar_readme.txt'] + +dll = env.SharedLibrary(target = 'bar.dll', + source = barsrcs) +buildtarget = [s for s in dll if str(s).endswith('dll')] +env.MSVSProject(target = 'Bar' + env['MSVSPROJECTSUFFIX'], + srcs = barsrcs, + incs = barincs, + localincs = barlocalincs, + resources = barresources, + misc = barmisc, + buildtarget = buildtarget, + variant = 'Release') +
Starting with version 2.4 of
+SCons it's also possible to specify the optional argument
+DebugSettings
, which creates files for debugging under
+Visual Studio:
A dictionary of debug settings that get written to the
+ .vcproj.user
or the
+ .vcxproj.user
file, depending on the version
+ installed. As it is done for cmdargs (see above), you can specify a
+ DebugSettings
dictionary per variant. If you
+ give only one, it will be propagated to all variants.
Currently, only Visual Studio v9.0 and Visual Studio
+version v11 are implemented, for other versions no file is generated. To
+generate the user file, you just need to add a
+DebugSettings
dictionary to the environment with the
+right parameters for your MSVS version. If the dictionary is empty, or does
+not contain any good value, no file will be generated.
Following +is a more contrived example, involving the setup of a project for variants and +DebugSettings:
# Assuming you store your defaults in a file +vars = Variables('variables.py') +msvcver = vars.args.get('vc', '9') + +# Check command args to force one Microsoft Visual Studio version +if msvcver == '9' or msvcver == '11': + env = Environment(MSVC_VERSION=msvcver+'.0', MSVC_BATCH=False) +else: + env = Environment() + +AddOption('--userfile', action='store_true', dest='userfile', default=False, + help="Create Visual Studio Project user file") + +# +# 1. Configure your Debug Setting dictionary with options you want in the list +# of allowed options, for instance if you want to create a user file to launch +# a specific application for testing your dll with Microsoft Visual Studio 2008 (v9): +# +V9DebugSettings = { + 'Command':'c:\\myapp\\using\\thisdll.exe', + 'WorkingDirectory': 'c:\\myapp\\using\\', + 'CommandArguments': '-p password', +# 'Attach':'false', +# 'DebuggerType':'3', +# 'Remote':'1', +# 'RemoteMachine': None, +# 'RemoteCommand': None, +# 'HttpUrl': None, +# 'PDBPath': None, +# 'SQLDebugging': None, +# 'Environment': '', +# 'EnvironmentMerge':'true', +# 'DebuggerFlavor': None, +# 'MPIRunCommand': None, +# 'MPIRunArguments': None, +# 'MPIRunWorkingDirectory': None, +# 'ApplicationCommand': None, +# 'ApplicationArguments': None, +# 'ShimCommand': None, +# 'MPIAcceptMode': None, +# 'MPIAcceptFilter': None, +} + +# +# 2. Because there are a lot of different options depending on the Microsoft +# Visual Studio version, if you use more than one version you have to +# define a dictionary per version, for instance if you want to create a user +# file to launch a specific application for testing your dll with Microsoft +# Visual Studio 2012 (v11): +# +V10DebugSettings = { + 'LocalDebuggerCommand': 'c:\\myapp\\using\\thisdll.exe', + 'LocalDebuggerWorkingDirectory': 'c:\\myapp\\using\\', + 'LocalDebuggerCommandArguments': '-p password', +# 'LocalDebuggerEnvironment': None, +# 'DebuggerFlavor': 'WindowsLocalDebugger', +# 'LocalDebuggerAttach': None, +# 'LocalDebuggerDebuggerType': None, +# 'LocalDebuggerMergeEnvironment': None, +# 'LocalDebuggerSQLDebugging': None, +# 'RemoteDebuggerCommand': None, +# 'RemoteDebuggerCommandArguments': None, +# 'RemoteDebuggerWorkingDirectory': None, +# 'RemoteDebuggerServerName': None, +# 'RemoteDebuggerConnection': None, +# 'RemoteDebuggerDebuggerType': None, +# 'RemoteDebuggerAttach': None, +# 'RemoteDebuggerSQLDebugging': None, +# 'DeploymentDirectory': None, +# 'AdditionalFiles': None, +# 'RemoteDebuggerDeployDebugCppRuntime': None, +# 'WebBrowserDebuggerHttpUrl': None, +# 'WebBrowserDebuggerDebuggerType': None, +# 'WebServiceDebuggerHttpUrl': None, +# 'WebServiceDebuggerDebuggerType': None, +# 'WebServiceDebuggerSQLDebugging': None, +} + +# +# 3. Select the dictionary you want depending on the version of visual Studio +# Files you want to generate. +# +if not env.GetOption('userfile'): + dbgSettings = None +elif env.get('MSVC_VERSION', None) == '9.0': + dbgSettings = V9DebugSettings +elif env.get('MSVC_VERSION', None) == '11.0': + dbgSettings = V10DebugSettings +else: + dbgSettings = None + +# +# 4. Add the dictionary to the DebugSettings keyword. +# +barsrcs = ['bar.cpp', 'dllmain.cpp', 'stdafx.cpp'] +barincs = ['targetver.h'] +barlocalincs = ['StdAfx.h'] +barresources = ['bar.rc','resource.h'] +barmisc = ['ReadMe.txt'] + +dll = env.SharedLibrary(target = 'bar.dll', + source = barsrcs) + +env.MSVSProject(target = 'Bar' + env['MSVSPROJECTSUFFIX'], + srcs = barsrcs, + incs = barincs, + localincs = barlocalincs, + resources = barresources, + misc = barmisc, + buildtarget = [dll[0]] * 2, + variant = ('Debug|Win32', 'Release|Win32'), + cmdargs = 'vc=%s' % msvcver, + DebugSettings = (dbgSettings, {})) +
MSVSSolution()
+ ,
+ env.MSVSSolution()
+ Builds a Microsoft Visual Studio solution +file.
This builds a Visual Studio solution file, based on the
+version of Visual Studio that is configured (either the latest installed
+version, or the version specified by $MSVS_VERSION
in the
+construction environment). For Visual Studio 6, it will generate a
+.dsw
file. For Visual Studio 7 (.NET), it will generate a
+.sln
file.
The following values must be +specified:
The name of the target .dsw or .sln file. The correct
+ suffix for the version of Visual Studio must be used, but the value
+ $MSVSSOLUTIONSUFFIX
will be defined to the correct value (see
+ example below).
The name of this particular variant, or a list of variant + names (the latter is only supported for MSVS 7 solutions). These are + typically things like "Debug" or "Release", but really can be anything + you want. For MSVS 7 they may also specify target platform, like this + "Debug|Xbox". Default platform is Win32.
A list of project file names, or Project nodes returned by
+ calls to the MSVSProject
Builder, to be placed into the solution
+ file. It should be noted that these file names are NOT added to the
+ $SOURCES environment variable in form of files, but rather as strings.
+ This is because they represent file names to be added to the solution
+ file, not the source files used to build the solution
+ file.
Example Usage:
+env.MSVSSolution(target = 'Bar' + env['MSVSSOLUTIONSUFFIX'], projects = ['bar' ++ env['MSVSPROJECTSUFFIX']], variant = 'Release') +
Object()
+ ,
+ env.Object()
+
+A synonym for the
+StaticObject
+builder method.
+
Package()
+ ,
+ env.Package()
+ +Builds a Binary Package of the given source files. +
+env.Package(source = FindInstalledFiles()) +
+Builds software distribution packages.
+Packages consist of files to install and packaging information.
+The former may be specified with the source
parameter and may be left out,
+in which case the FindInstalledFiles
function will collect
+all files that have an Install
or InstallAs
Builder attached.
+If the target
is not specified
+it will be deduced from additional information given to this Builder.
+
+The packaging information is specified
+with the help of construction variables documented below.
+This information is called a tag to stress that
+some of them can also be attached to files with the Tag
function.
+The mandatory ones will complain if they were not specified.
+They vary depending on chosen target packager.
+
+The target packager may be selected with the "PACKAGETYPE" command line
+option or with the $PACKAGETYPE
construction variable. Currently
+the following packagers available:
+
+ * msi - Microsoft Installer + * rpm - RPM Package Manger + * ipkg - Itsy Package Management System + * tarbz2 - bzip2 compressed tar + * targz - gzip compressed tar + * tarxz - xz compressed tar + * zip - zip file + * src_tarbz2 - bzip2 compressed tar source + * src_targz - gzip compressed tar source + * src_tarxz - xz compressed tar source + * src_zip - zip file source +
+An updated list is always available under the "package_type" option when +running "scons --help" on a project that has packaging activated. +
+env = Environment(tools=['default', 'packaging']) +env.Install('/bin/', 'my_program') +env.Package( NAME = 'foo', + VERSION = '1.2.3', + PACKAGEVERSION = 0, + PACKAGETYPE = 'rpm', + LICENSE = 'gpl', + SUMMARY = 'balalalalal', + DESCRIPTION = 'this should be really really long', + X_RPM_GROUP = 'Application/fu', + SOURCE_URL = 'http://foo.org/foo-1.2.3.tar.gz' + ) +
PCH()
+ ,
+ env.PCH()
+ +Builds a Microsoft Visual C++ precompiled header. +Calling this builder method +returns a list of two targets: the PCH as the first element, and the object +file as the second element. Normally the object file is ignored. +This builder method is only +provided when Microsoft Visual C++ is being used as the compiler. +The PCH builder method is generally used in +conjunction with the PCH construction variable to force object files to use +the precompiled header: +
+env['PCH'] = env.PCH('StdAfx.cpp')[0] +
PDF()
+ ,
+ env.PDF()
+
+Builds a .pdf
file
+from a .dvi
input file
+(or, by extension, a .tex
,
+.ltx
,
+or
+.latex
input file).
+The suffix specified by the $PDFSUFFIX
construction variable
+(.pdf
by default)
+is added automatically to the target
+if it is not already present. Example:
+
+# builds from aaa.tex +env.PDF(target = 'aaa.pdf', source = 'aaa.tex') +# builds bbb.pdf from bbb.dvi +env.PDF(target = 'bbb', source = 'bbb.dvi') +
POInit()
+ ,
+ env.POInit()
+
+This builder belongs to msginit
tool. The builder initializes missing
+PO
file(s) if $POAUTOINIT
is set. If
+$POAUTOINIT
is not set (default), POInit
prints instruction for
+user (that is supposed to be a translator), telling how the
+PO
file should be initialized. In normal projects
+you should not use POInit
and use POUpdate
+instead. POUpdate
chooses intelligently between
+msgmerge(1) and msginit(1). POInit
+always uses msginit(1) and should be regarded as builder for
+special purposes or for temporary use (e.g. for quick, one time initialization
+of a bunch of PO
files) or for tests.
+
+Target nodes defined through POInit
are not built by default (they're
+Ignore
d from '.'
node) but are added to
+special Alias
('po-create'
by default).
+The alias name may be changed through the $POCREATE_ALIAS
+construction variable. All PO
files defined through
+POInit
may be easily initialized by scons po-create.
+
+Example 1.
+Initialize en.po
and pl.po
from
+messages.pot
:
+
+ # ... + env.POInit(['en', 'pl']) # messages.pot --> [en.po, pl.po] +
+Example 2.
+Initialize en.po
and pl.po
from
+foo.pot
:
+
+ # ... + env.POInit(['en', 'pl'], ['foo']) # foo.pot --> [en.po, pl.po] +
+Example 3.
+Initialize en.po
and pl.po
from
+foo.pot
but using $POTDOMAIN
construction
+variable:
+
+ # ... + env.POInit(['en', 'pl'], POTDOMAIN='foo') # foo.pot --> [en.po, pl.po] +
+Example 4.
+Initialize PO
files for languages defined in
+LINGUAS
file. The files will be initialized from template
+messages.pot
:
+
+ # ... + env.POInit(LINGUAS_FILE = 1) # needs 'LINGUAS' file +
+Example 5.
+Initialize en.po
and pl.pl
+PO
files plus files for languages defined in
+LINGUAS
file. The files will be initialized from template
+messages.pot
:
+
+ # ... + env.POInit(['en', 'pl'], LINGUAS_FILE = 1) +
+Example 6.
+You may preconfigure your environment first, and then initialize
+PO
files:
+
+ # ... + env['POAUTOINIT'] = 1 + env['LINGUAS_FILE'] = 1 + env['POTDOMAIN'] = 'foo' + env.POInit() +
+which has same efect as: +
+ # ... + env.POInit(POAUTOINIT = 1, LINGUAS_FILE = 1, POTDOMAIN = 'foo') +
PostScript()
+ ,
+ env.PostScript()
+
+Builds a .ps
file
+from a .dvi
input file
+(or, by extension, a .tex
,
+.ltx
,
+or
+.latex
input file).
+The suffix specified by the $PSSUFFIX
construction variable
+(.ps
by default)
+is added automatically to the target
+if it is not already present. Example:
+
+# builds from aaa.tex +env.PostScript(target = 'aaa.ps', source = 'aaa.tex') +# builds bbb.ps from bbb.dvi +env.PostScript(target = 'bbb', source = 'bbb.dvi') +
POTUpdate()
+ ,
+ env.POTUpdate()
+
+The builder belongs to xgettext
tool. The builder updates target
+POT
file if exists or creates one if it doesn't. The node is
+not built by default (i.e. it is Ignore
d from
+'.'
), but only on demand (i.e. when given
+POT
file is required or when special alias is invoked). This
+builder adds its targe node (messages.pot
, say) to a
+special alias (pot-update
by default, see
+$POTUPDATE_ALIAS
) so you can update/create them easily with
+scons pot-update. The file is not written until there is no
+real change in internationalized messages (or in comments that enter
+POT
file).
+
+
You may see xgettext(1) being invoked by the
+xgettext
tool even if there is no real change in internationalized
+messages (so the POT
file is not being updated). This
+happens every time a source file has changed. In such case we invoke
+xgettext(1) and compare its output with the content of
+POT
file to decide whether the file should be updated or
+not.
+
+Example 1.
+Let's create po/
directory and place following
+SConstruct
script there:
+
+ # SConstruct in 'po/' subdir + env = Environment( tools = ['default', 'xgettext'] ) + env.POTUpdate(['foo'], ['../a.cpp', '../b.cpp']) + env.POTUpdate(['bar'], ['../c.cpp', '../d.cpp']) +
+Then invoke scons few times: +
+ user@host:$ scons # Does not create foo.pot nor bar.pot + user@host:$ scons foo.pot # Updates or creates foo.pot + user@host:$ scons pot-update # Updates or creates foo.pot and bar.pot + user@host:$ scons -c # Does not clean foo.pot nor bar.pot. +
+the results shall be as the comments above say. +
+Example 2.
+The POTUpdate
builder may be used with no target specified, in which
+case default target messages.pot
will be used. The
+default target may also be overridden by setting $POTDOMAIN
construction
+variable or providing it as an override to POTUpdate
builder:
+
+ # SConstruct script + env = Environment( tools = ['default', 'xgettext'] ) + env['POTDOMAIN'] = "foo" + env.POTUpdate(source = ["a.cpp", "b.cpp"]) # Creates foo.pot ... + env.POTUpdate(POTDOMAIN = "bar", source = ["c.cpp", "d.cpp"]) # and bar.pot +
+Example 3.
+The sources may be specified within separate file, for example
+POTFILES.in
:
+
+ # POTFILES.in in 'po/' subdirectory + ../a.cpp + ../b.cpp + # end of file +
+The name of the file (POTFILES.in
) containing the list of
+sources is provided via $XGETTEXTFROM
:
+
+ # SConstruct file in 'po/' subdirectory + env = Environment( tools = ['default', 'xgettext'] ) + env.POTUpdate(XGETTEXTFROM = 'POTFILES.in') +
+Example 4.
+You may use $XGETTEXTPATH
to define source search path. Assume, for
+example, that you have files a.cpp
,
+b.cpp
, po/SConstruct
,
+po/POTFILES.in
. Then your POT
-related
+files could look as below:
+
+ # POTFILES.in in 'po/' subdirectory + a.cpp + b.cpp + # end of file +
+ # SConstruct file in 'po/' subdirectory + env = Environment( tools = ['default', 'xgettext'] ) + env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH='../') +
+Example 5.
+Multiple search directories may be defined within a list, i.e.
+XGETTEXTPATH = ['dir1', 'dir2', ...]
. The order in the list
+determines the search order of source files. The path to the first file found
+is used.
+
+Let's create 0/1/po/SConstruct
script:
+
+ # SConstruct file in '0/1/po/' subdirectory + env = Environment( tools = ['default', 'xgettext'] ) + env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH=['../', '../../']) +
+and 0/1/po/POTFILES.in
:
+
+ # POTFILES.in in '0/1/po/' subdirectory + a.cpp + # end of file +
+Write two *.cpp
files, the first one is
+0/a.cpp
:
+
+ /* 0/a.cpp */ + gettext("Hello from ../../a.cpp") +
+and the second is 0/1/a.cpp
:
+
+ /* 0/1/a.cpp */ + gettext("Hello from ../a.cpp") +
+then run scons. You'll obtain 0/1/po/messages.pot
with the
+message "Hello from ../a.cpp"
. When you reverse order in
+$XGETTEXTFOM
, i.e. when you write SConscript as
+
+ # SConstruct file in '0/1/po/' subdirectory + env = Environment( tools = ['default', 'xgettext'] ) + env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH=['../../', '../']) +
+then the messages.pot
will contain
+msgid "Hello from ../../a.cpp"
line and not
+msgid "Hello from ../a.cpp"
.
+
POUpdate()
+ ,
+ env.POUpdate()
+
+The builder belongs to msgmerge
tool. The builder updates
+PO
files with msgmerge(1), or initializes
+missing PO
files as described in documentation of
+msginit
tool and POInit
builder (see also
+$POAUTOINIT
). Note, that POUpdate
does not add its
+targets to po-create
alias as POInit
+does.
+
+Target nodes defined through POUpdate
are not built by default
+(they're Ignore
d from '.'
node). Instead,
+they are added automatically to special Alias
+('po-update'
by default). The alias name may be changed
+through the $POUPDATE_ALIAS
construction variable. You can easily
+update PO
files in your project by scons
+po-update.
+
+Example 1.
+Update en.po
and pl.po
from
+messages.pot
template (see also $POTDOMAIN
),
+assuming that the later one exists or there is rule to build it (see
+POTUpdate
):
+
+ # ... + env.POUpdate(['en','pl']) # messages.pot --> [en.po, pl.po] +
+Example 2.
+Update en.po
and pl.po
from
+foo.pot
template:
+
+ # ... + env.POUpdate(['en', 'pl'], ['foo']) # foo.pot --> [en.po, pl.pl] +
+Example 3.
+Update en.po
and pl.po
from
+foo.pot
(another version):
+
+ # ... + env.POUpdate(['en', 'pl'], POTDOMAIN='foo') # foo.pot -- > [en.po, pl.pl] +
+Example 4.
+Update files for languages defined in LINGUAS
file. The
+files are updated from messages.pot
template:
+
+ # ... + env.POUpdate(LINGUAS_FILE = 1) # needs 'LINGUAS' file +
+Example 5.
+Same as above, but update from foo.pot
template:
+
+ # ... + env.POUpdate(LINGUAS_FILE = 1, source = ['foo']) +
+Example 6.
+Update en.po
and pl.po
plus files for
+languages defined in LINGUAS
file. The files are updated
+from messages.pot
template:
+
+ # produce 'en.po', 'pl.po' + files defined in 'LINGUAS': + env.POUpdate(['en', 'pl' ], LINGUAS_FILE = 1) +
+Example 7.
+Use $POAUTOINIT
to automatically initialize PO
file
+if it doesn't exist:
+
+ # ... + env.POUpdate(LINGUAS_FILE = 1, POAUTOINIT = 1) +
+Example 8.
+Update PO
files for languages defined in
+LINGUAS
file. The files are updated from
+foo.pot
template. All necessary settings are
+pre-configured via environment.
+
+ # ... + env['POAUTOINIT'] = 1 + env['LINGUAS_FILE'] = 1 + env['POTDOMAIN'] = 'foo' + env.POUpdate() +
Program()
+ ,
+ env.Program()
+
+Builds an executable given one or more object files
+or C, C++, D, or Fortran source files.
+If any C, C++, D or Fortran source files are specified,
+then they will be automatically
+compiled to object files using the
+Object
+builder method;
+see that builder method's description for
+a list of legal source file suffixes
+and how they are interpreted.
+The target executable file prefix
+(specified by the $PROGPREFIX
construction variable; nothing by default)
+and suffix
+(specified by the $PROGSUFFIX
construction variable;
+by default, .exe
on Windows systems,
+nothing on POSIX systems)
+are automatically added to the target if not already present.
+Example:
+
+env.Program(target = 'foo', source = ['foo.o', 'bar.c', 'baz.f']) +
ProgramAllAtOnce()
+ ,
+ env.ProgramAllAtOnce()
+ + Builds an executable from D sources without first creating individual + objects for each file. +
+ D sources can be compiled file-by-file as C and C++ source are, and
+ D is integrated into the scons
Object and Program builders for
+ this model of build. D codes can though do whole source
+ meta-programming (some of the testing frameworks do this). For this
+ it is imperative that all sources are compiled and linked in a single call of
+ the D compiler. This builder serves that purpose.
+
+ env.ProgramAllAtOnce('executable', ['mod_a.d, mod_b.d', 'mod_c.d']) +
+ This command will compile the modules mod_a, mod_b, and mod_c in a + single compilation process without first creating object files for + the modules. Some of the D compilers will create executable.o others + will not. +
+ Builds an executable from D sources without first creating individual + objects for each file. +
+ D sources can be compiled file-by-file as C and C++ source are, and
+ D is integrated into the scons
Object and Program builders for
+ this model of build. D codes can though do whole source
+ meta-programming (some of the testing frameworks do this). For this
+ it is imperative that all sources are compiled and linked in a single call of
+ the D compiler. This builder serves that purpose.
+
+ env.ProgramAllAtOnce('executable', ['mod_a.d, mod_b.d', 'mod_c.d']) +
+ This command will compile the modules mod_a, mod_b, and mod_c in a + single compilation process without first creating object files for + the modules. Some of the D compilers will create executable.o others + will not. +
+ Builds an executable from D sources without first creating individual + objects for each file. +
+ D sources can be compiled file-by-file as C and C++ source are, and
+ D is integrated into the scons
Object and Program builders for
+ this model of build. D codes can though do whole source
+ meta-programming (some of the testing frameworks do this). For this
+ it is imperative that all sources are compiled and linked in a single call of
+ the D compiler. This builder serves that purpose.
+
+ env.ProgramAllAtOnce('executable', ['mod_a.d, mod_b.d', 'mod_c.d']) +
+ This command will compile the modules mod_a, mod_b, and mod_c in a + single compilation process without first creating object files for + the modules. Some of the D compilers will create executable.o others + will not. +
RES()
+ ,
+ env.RES()
+
+Builds a Microsoft Visual C++ resource file.
+This builder method is only provided
+when Microsoft Visual C++ or MinGW is being used as the compiler. The
+.res
+(or
+.o
+for MinGW) suffix is added to the target name if no other suffix is given.
+The source
+file is scanned for implicit dependencies as though it were a C file.
+Example:
+
+env.RES('resource.rc') +
RMIC()
+ ,
+ env.RMIC()
+
+Builds stub and skeleton class files
+for remote objects
+from Java .class
files.
+The target is a directory
+relative to which the stub
+and skeleton class files will be written.
+The source can be the names of .class
files,
+or the objects return from the
+Java
+builder method.
+
+If the construction variable
+$JAVACLASSDIR
+is set, either in the environment
+or in the call to the
+RMIC
+builder method itself,
+then the value of the variable
+will be stripped from the
+beginning of any .class
+file names.
+
+classes = env.Java(target = 'classdir', source = 'src') +env.RMIC(target = 'outdir1', source = classes) + +env.RMIC(target = 'outdir2', + source = ['package/foo.class', 'package/bar.class']) + +env.RMIC(target = 'outdir3', + source = ['classes/foo.class', 'classes/bar.class'], + JAVACLASSDIR = 'classes') +
RPCGenClient()
+ ,
+ env.RPCGenClient()
+
+Generates an RPC client stub (_clnt.c
) file
+from a specified RPC (.x
) source file.
+Because rpcgen only builds output files
+in the local directory,
+the command will be executed
+in the source file's directory by default.
+
+# Builds src/rpcif_clnt.c +env.RPCGenClient('src/rpcif.x') +
RPCGenHeader()
+ ,
+ env.RPCGenHeader()
+
+Generates an RPC header (.h
) file
+from a specified RPC (.x
) source file.
+Because rpcgen only builds output files
+in the local directory,
+the command will be executed
+in the source file's directory by default.
+
+# Builds src/rpcif.h +env.RPCGenHeader('src/rpcif.x') +
RPCGenService()
+ ,
+ env.RPCGenService()
+
+Generates an RPC server-skeleton (_svc.c
) file
+from a specified RPC (.x
) source file.
+Because rpcgen only builds output files
+in the local directory,
+the command will be executed
+in the source file's directory by default.
+
+# Builds src/rpcif_svc.c +env.RPCGenClient('src/rpcif.x') +
RPCGenXDR()
+ ,
+ env.RPCGenXDR()
+
+Generates an RPC XDR routine (_xdr.c
) file
+from a specified RPC (.x
) source file.
+Because rpcgen only builds output files
+in the local directory,
+the command will be executed
+in the source file's directory by default.
+
+# Builds src/rpcif_xdr.c +env.RPCGenClient('src/rpcif.x') +
SharedLibrary()
+ ,
+ env.SharedLibrary()
+
+Builds a shared library
+(.so
on a POSIX system,
+.dll
on Windows)
+given one or more object files
+or C, C++, D or Fortran source files.
+If any source files are given,
+then they will be automatically
+compiled to object files.
+The static library prefix and suffix (if any)
+are automatically added to the target.
+The target library file prefix
+(specified by the $SHLIBPREFIX
construction variable;
+by default, lib
on POSIX systems,
+nothing on Windows systems)
+and suffix
+(specified by the $SHLIBSUFFIX
construction variable;
+by default, .dll
on Windows systems,
+.so
on POSIX systems)
+are automatically added to the target if not already present.
+Example:
+
+env.SharedLibrary(target = 'bar', source = ['bar.c', 'foo.o']) +
+On Windows systems, the
+SharedLibrary
+builder method will always build an import
+(.lib
) library
+in addition to the shared (.dll
) library,
+adding a .lib
library with the same basename
+if there is not already a .lib
file explicitly
+listed in the targets.
+
+On Cygwin systems, the
+SharedLibrary
+builder method will always build an import
+(.dll.a
) library
+in addition to the shared (.dll
) library,
+adding a .dll.a
library with the same basename
+if there is not already a .dll.a
file explicitly
+listed in the targets.
+
+Any object files listed in the
+source
+must have been built for a shared library
+(that is, using the
+SharedObject
+builder method).
+scons
+will raise an error if there is any mismatch.
+
+On some platforms, there is a distinction between a shared library
+(loaded automatically by the system to resolve external references)
+and a loadable module (explicitly loaded by user action).
+For maximum portability, use the LoadableModule
builder for the latter.
+
+When the $SHLIBVERSION
construction variable is defined a versioned
+shared library is created. This modifies the $SHLINKFLAGS
as required,
+adds the version number to the library name, and creates the symlinks that
+are needed.
+
+env.SharedLibrary(target = 'bar', source = ['bar.c', 'foo.o'], SHLIBVERSION='1.5.2') +
+On a POSIX system, versions with a single token create exactly one symlink: +libbar.so.6 would have symlinks libbar.so only. +On a POSIX system, versions with two or more +tokens create exactly two symlinks: libbar.so.2.3.1 would have symlinks +libbar.so and libbar.so.2; on a Darwin (OSX) system the library would be +libbar.2.3.1.dylib and the link would be libbar.dylib. +
+On Windows systems, specifying
+register=1
+will cause the .dll
to be
+registered after it is built using REGSVR32.
+The command that is run
+("regsvr32" by default) is determined by $REGSVR
construction
+variable, and the flags passed are determined by $REGSVRFLAGS
. By
+default, $REGSVRFLAGS
includes the /s
option,
+to prevent dialogs from popping
+up and requiring user attention when it is run. If you change
+$REGSVRFLAGS
, be sure to include the /s
option.
+For example,
+
+env.SharedLibrary(target = 'bar', + source = ['bar.cxx', 'foo.obj'], + register=1) +
+will register bar.dll
as a COM object
+when it is done linking it.
+
SharedObject()
+ ,
+ env.SharedObject()
+
+Builds an object file for
+inclusion in a shared library.
+Source files must have one of the same set of extensions
+specified above for the
+StaticObject
+builder method.
+On some platforms building a shared object requires additional
+compiler option
+(e.g. -fPIC
for gcc)
+in addition to those needed to build a
+normal (static) object, but on some platforms there is no difference between a
+shared object and a normal (static) one. When there is a difference, SCons
+will only allow shared objects to be linked into a shared library, and will
+use a different suffix for shared objects. On platforms where there is no
+difference, SCons will allow both normal (static)
+and shared objects to be linked into a
+shared library, and will use the same suffix for shared and normal
+(static) objects.
+The target object file prefix
+(specified by the $SHOBJPREFIX
construction variable;
+by default, the same as $OBJPREFIX
)
+and suffix
+(specified by the $SHOBJSUFFIX
construction variable)
+are automatically added to the target if not already present.
+Examples:
+
+env.SharedObject(target = 'ddd', source = 'ddd.c') +env.SharedObject(target = 'eee.o', source = 'eee.cpp') +env.SharedObject(target = 'fff.obj', source = 'fff.for') +
+Note that the source files will be scanned
+according to the suffix mappings in the
+SourceFileScanner
+object.
+See the section "Scanner Objects,"
+below, for more information.
+
StaticLibrary()
+ ,
+ env.StaticLibrary()
+
+Builds a static library given one or more object files
+or C, C++, D or Fortran source files.
+If any source files are given,
+then they will be automatically
+compiled to object files.
+The static library prefix and suffix (if any)
+are automatically added to the target.
+The target library file prefix
+(specified by the $LIBPREFIX
construction variable;
+by default, lib
on POSIX systems,
+nothing on Windows systems)
+and suffix
+(specified by the $LIBSUFFIX
construction variable;
+by default, .lib
on Windows systems,
+.a
on POSIX systems)
+are automatically added to the target if not already present.
+Example:
+
+env.StaticLibrary(target = 'bar', source = ['bar.c', 'foo.o']) +
+Any object files listed in the
+source
+must have been built for a static library
+(that is, using the
+StaticObject
+builder method).
+scons
+will raise an error if there is any mismatch.
+
StaticObject()
+ ,
+ env.StaticObject()
+ +Builds a static object file +from one or more C, C++, D, or Fortran source files. +Source files must have one of the following extensions: +
+ .asm assembly language file + .ASM assembly language file + .c C file + .C Windows: C file + POSIX: C++ file + .cc C++ file + .cpp C++ file + .cxx C++ file + .cxx C++ file + .c++ C++ file + .C++ C++ file + .d D file + .f Fortran file + .F Windows: Fortran file + POSIX: Fortran file + C pre-processor + .for Fortran file + .FOR Fortran file + .fpp Fortran file + C pre-processor + .FPP Fortran file + C pre-processor + .m Object C file + .mm Object C++ file + .s assembly language file + .S Windows: assembly language file + ARM: CodeSourcery Sourcery Lite + .sx assembly language file + C pre-processor + POSIX: assembly language file + C pre-processor + .spp assembly language file + C pre-processor + .SPP assembly language file + C pre-processor +
+The target object file prefix
+(specified by the $OBJPREFIX
construction variable; nothing by default)
+and suffix
+(specified by the $OBJSUFFIX
construction variable;
+.obj
on Windows systems,
+.o
on POSIX systems)
+are automatically added to the target if not already present.
+Examples:
+
+env.StaticObject(target = 'aaa', source = 'aaa.c') +env.StaticObject(target = 'bbb.o', source = 'bbb.c++') +env.StaticObject(target = 'ccc.obj', source = 'ccc.f') +
+Note that the source files will be scanned
+according to the suffix mappings in
+SourceFileScanner
+object.
+See the section "Scanner Objects,"
+below, for more information.
+
Substfile()
+ ,
+ env.Substfile()
+
+The Substfile
builder creates a single text file from another file or set of
+files by concatenating them with $LINESEPARATOR
and replacing text
+using the $SUBST_DICT
construction variable. Nested lists of source files
+are flattened. See also Textfile
.
+
+If a single source file is present with an .in
suffix,
+the suffix is stripped and the remainder is used as the default target name.
+
+The prefix and suffix specified by the $SUBSTFILEPREFIX
+and $SUBSTFILESUFFIX
construction variables
+(the null string by default in both cases)
+are automatically added to the target if they are not already present.
+
+If a construction variable named $SUBST_DICT
is present,
+it may be either a Python dictionary or a sequence of (key,value) tuples.
+If it is a dictionary it is converted into a list of tuples in an arbitrary order,
+so if one key is a prefix of another key
+or if one substitution could be further expanded by another subsitition,
+it is unpredictable whether the expansion will occur.
+
+Any occurrences of a key in the source +are replaced by the corresponding value, +which may be a Python callable function or a string. +If the value is a callable, it is called with no arguments to get a string. +Strings are subst-expanded +and the result replaces the key. +
+env = Environment(tools = ['default', 'textfile']) + +env['prefix'] = '/usr/bin' +script_dict = {'@prefix@': '/bin', '@exec_prefix@': '$prefix'} +env.Substfile('script.in', SUBST_DICT = script_dict) + +conf_dict = {'%VERSION%': '1.2.3', '%BASE%': 'MyProg'} +env.Substfile('config.h.in', conf_dict, SUBST_DICT = conf_dict) + +# UNPREDICTABLE - one key is a prefix of another +bad_foo = {'$foo': '$foo', '$foobar': '$foobar'} +env.Substfile('foo.in', SUBST_DICT = bad_foo) + +# PREDICTABLE - keys are applied longest first +good_foo = [('$foobar', '$foobar'), ('$foo', '$foo')] +env.Substfile('foo.in', SUBST_DICT = good_foo) + +# UNPREDICTABLE - one substitution could be futher expanded +bad_bar = {'@bar@': '@soap@', '@soap@': 'lye'} +env.Substfile('bar.in', SUBST_DICT = bad_bar) + +# PREDICTABLE - substitutions are expanded in order +good_bar = (('@bar@', '@soap@'), ('@soap@', 'lye')) +env.Substfile('bar.in', SUBST_DICT = good_bar) + +# the SUBST_DICT may be in common (and not an override) +substutions = {} +subst = Environment(tools = ['textfile'], SUBST_DICT = substitutions) +substitutions['@foo@'] = 'foo' +subst['SUBST_DICT']['@bar@'] = 'bar' +subst.Substfile('pgm1.c', [Value('#include "@foo@.h"'), + Value('#include "@bar@.h"'), + "common.in", + "pgm1.in" + ]) +subst.Substfile('pgm2.c', [Value('#include "@foo@.h"'), + Value('#include "@bar@.h"'), + "common.in", + "pgm2.in" + ]) + +
Tar()
+ ,
+ env.Tar()
+
+Builds a tar archive of the specified files
+and/or directories.
+Unlike most builder methods,
+the
+Tar
+builder method may be called multiple times
+for a given target;
+each additional call
+adds to the list of entries
+that will be built into the archive.
+Any source directories will
+be scanned for changes to
+any on-disk files,
+regardless of whether or not
+scons
+knows about them from other Builder or function calls.
+
+env.Tar('src.tar', 'src') + +# Create the stuff.tar file. +env.Tar('stuff', ['subdir1', 'subdir2']) +# Also add "another" to the stuff.tar file. +env.Tar('stuff', 'another') + +# Set TARFLAGS to create a gzip-filtered archive. +env = Environment(TARFLAGS = '-c -z') +env.Tar('foo.tar.gz', 'foo') + +# Also set the suffix to .tgz. +env = Environment(TARFLAGS = '-c -z', + TARSUFFIX = '.tgz') +env.Tar('foo') +
Textfile()
+ ,
+ env.Textfile()
+
+The Textfile
builder generates a single text file.
+The source strings constitute the lines;
+nested lists of sources are flattened.
+$LINESEPARATOR
is used to separate the strings.
+
+If present, the $SUBST_DICT
construction variable
+is used to modify the strings before they are written;
+see the Substfile
description for details.
+
+The prefix and suffix specified by the $TEXTFILEPREFIX
+and $TEXTFILESUFFIX
construction variables
+(the null string and .txt
by default, respectively)
+are automatically added to the target if they are not already present.
+Examples:
+
+# builds/writes foo.txt +env.Textfile(target = 'foo.txt', source = ['Goethe', 42, 'Schiller']) + +# builds/writes bar.txt +env.Textfile(target = 'bar', + source = ['lalala', 'tanteratei'], + LINESEPARATOR='|*') + +# nested lists are flattened automatically +env.Textfile(target = 'blob', + source = ['lalala', ['Goethe', 42 'Schiller'], 'tanteratei']) + +# files may be used as input by wraping them in File() +env.Textfile(target = 'concat', # concatenate files with a marker between + source = [File('concat1'), File('concat2')], + LINESEPARATOR = '====================\n') + +Results are: +foo.txt + ....8<---- + Goethe + 42 + Schiller + ....8<---- (no linefeed at the end) + +bar.txt: + ....8<---- + lalala|*tanteratei + ....8<---- (no linefeed at the end) + +blob.txt + ....8<---- + lalala + Goethe + 42 + Schiller + tanteratei + ....8<---- (no linefeed at the end) +
Translate()
+ ,
+ env.Translate()
+
+This pseudo-builder belongs to gettext
toolset. The builder extracts
+internationalized messages from source files, updates POT
+template (if necessary) and then updates PO
translations (if
+necessary). If $POAUTOINIT
is set, missing PO
files
+will be automatically created (i.e. without translator person intervention).
+The variables $LINGUAS_FILE
and $POTDOMAIN
are taken into
+acount too. All other construction variables used by POTUpdate
, and
+POUpdate
work here too.
+
+Example 1.
+The simplest way is to specify input files and output languages inline in
+a SCons script when invoking Translate
+
+# SConscript in 'po/' directory +env = Environment( tools = ["default", "gettext"] ) +env['POAUTOINIT'] = 1 +env.Translate(['en','pl'], ['../a.cpp','../b.cpp']) +
+Example 2.
+If you wish, you may also stick to conventional style known from
+autotools, i.e. using
+POTFILES.in
and LINGUAS
files
+
+# LINGUAS +en pl +#end +
+# POTFILES.in +a.cpp +b.cpp +# end +
+# SConscript +env = Environment( tools = ["default", "gettext"] ) +env['POAUTOINIT'] = 1 +env['XGETTEXTPATH'] = ['../'] +env.Translate(LINGUAS_FILE = 1, XGETTEXTFROM = 'POTFILES.in') +
+The last approach is perhaps the recommended one. It allows easily split
+internationalization/localization onto separate SCons scripts, where a script
+in source tree is responsible for translations (from sources to
+PO
files) and script(s) under variant directories are
+responsible for compilation of PO
to MO
+files to and for installation of MO
files. The "gluing
+factor" synchronizing these two scripts is then the content of
+LINGUAS
file. Note, that the updated
+POT
and PO
files are usually going to be
+committed back to the repository, so they must be updated within the source
+directory (and not in variant directories). Additionaly, the file listing of
+po/
directory contains LINGUAS
file,
+so the source tree looks familiar to translators, and they may work with the
+project in their usual way.
+
+Example 3. +Let's prepare a development tree as below +
+ project/ + + SConstruct + + build/ + + src/ + + po/ + + SConscript + + SConscript.i18n + + POTFILES.in + + LINGUAS +
+with build
being variant directory. Write the top-level
+SConstruct
script as follows
+
+ # SConstruct + env = Environment( tools = ["default", "gettext"] ) + VariantDir('build', 'src', duplicate = 0) + env['POAUTOINIT'] = 1 + SConscript('src/po/SConscript.i18n', exports = 'env') + SConscript('build/po/SConscript', exports = 'env') +
+the src/po/SConscript.i18n
as
+
+ # src/po/SConscript.i18n + Import('env') + env.Translate(LINGUAS_FILE=1, XGETTEXTFROM='POTFILES.in', XGETTEXTPATH=['../']) +
+and the src/po/SConscript
+
+ # src/po/SConscript + Import('env') + env.MOFiles(LINGUAS_FILE = 1) +
+Such setup produces POT
and PO
files
+under source tree in src/po/
and binary
+MO
files under variant tree in
+build/po/
. This way the POT
and
+PO
files are separated from other output files, which must
+not be committed back to source repositories (e.g. MO
+files).
+
+
In above example, the PO
files are not updated,
+nor created automatically when you issue scons '.' command.
+The files must be updated (created) by hand via scons
+po-update and then MO
files can be compiled by
+running scons '.'.
+
TypeLibrary()
+ ,
+ env.TypeLibrary()
+
+Builds a Windows type library (.tlb
)
+file from an input IDL file (.idl
).
+In addition, it will build the associated interface stub and
+proxy source files,
+naming them according to the base name of the .idl
file.
+For example,
+
+env.TypeLibrary(source="foo.idl") +
+Will create foo.tlb
,
+foo.h
,
+foo_i.c
,
+foo_p.c
+and
+foo_data.c
+files.
+
Uic()
+ ,
+ env.Uic()
+
+Builds a header file, an implementation file and a moc file from an ui file.
+and returns the corresponding nodes in the above order.
+This builder is only available after using the tool 'qt'. Note: you can
+specify .ui
files directly as source
+files to the Program
,
+Library
and SharedLibrary
builders
+without using this builder. Using this builder lets you override the standard
+naming conventions (be careful: prefixes are always prepended to names of
+built files; if you don't want prefixes, you may set them to ``).
+See the $QTDIR
variable for more information.
+Example:
+
+env.Uic('foo.ui') # -> ['foo.h', 'uic_foo.cc', 'moc_foo.cc'] +env.Uic(target = Split('include/foo.h gen/uicfoo.cc gen/mocfoo.cc'), + source = 'foo.ui') # -> ['include/foo.h', 'gen/uicfoo.cc', 'gen/mocfoo.cc'] +
Zip()
+ ,
+ env.Zip()
+
+Builds a zip archive of the specified files
+and/or directories.
+Unlike most builder methods,
+the
+Zip
+builder method may be called multiple times
+for a given target;
+each additional call
+adds to the list of entries
+that will be built into the archive.
+Any source directories will
+be scanned for changes to
+any on-disk files,
+regardless of whether or not
+scons
+knows about them from other Builder or function calls.
+
+env.Zip('src.zip', 'src') + +# Create the stuff.zip file. +env.Zip('stuff', ['subdir1', 'subdir2']) +# Also add "another" to the stuff.tar file. +env.Zip('stuff', 'another') +
+ +This appendix contains descriptions of all of the +Tools modules that are +available "out of the box" in this version of SCons. + +
+Sets construction variables for the 386ASM assembler +for the Phar Lap ETS embedded operating system. +
Sets: $AS
, $ASCOM
, $ASFLAGS
, $ASPPCOM
, $ASPPFLAGS
.
Uses: $CC
, $CPPFLAGS
, $_CPPDEFFLAGS
, $_CPPINCFLAGS
.
+Sets construction variables for the IMB xlc / Visual Age C++ compiler. +
Sets: $CXX
, $CXXVERSION
, $SHCXX
, $SHOBJSUFFIX
.
+Sets construction variables for the IBM xlc / Visual Age C compiler. +
Sets: $CC
, $CCVERSION
, $SHCC
.
+Sets construction variables for the IBM Visual Age f77 Fortran compiler. +
+Sets construction variables for the IBM Visual Age linker. +
Sets: $LINKFLAGS
, $SHLIBSUFFIX
, $SHLINKFLAGS
.
+ Sets construction variables for the Apple linker + (similar to the GNU linker). +
Sets: $APPLELINK_COMPATIBILITY_VERSION
, $APPLELINK_CURRENT_VERSION
, $APPLELINK_NO_COMPATIBILITY_VERSION
, $APPLELINK_NO_CURRENT_VERSION
, $FRAMEWORKPATHPREFIX
, $LDMODULECOM
, $LDMODULEFLAGS
, $LDMODULEPREFIX
, $LDMODULESUFFIX
, $LINKCOM
, $SHLINKCOM
, $SHLINKFLAGS
, $_APPLELINK_COMPATIBILITY_VERSION
, $_APPLELINK_CURRENT_VERSION
, $_FRAMEWORKPATH
, $_FRAMEWORKS
.
Uses: $FRAMEWORKSFLAGS
.
+Sets construction variables for the ar library archiver. +
Sets: $AR
, $ARCOM
, $ARFLAGS
, $LIBPREFIX
, $LIBSUFFIX
, $RANLIB
, $RANLIBCOM
, $RANLIBFLAGS
.
+Sets construction variables for the as assembler. +
Sets: $AS
, $ASCOM
, $ASFLAGS
, $ASPPCOM
, $ASPPFLAGS
.
Uses: $CC
, $CPPFLAGS
, $_CPPDEFFLAGS
, $_CPPINCFLAGS
.
+Sets construction variables for the bcc32 compiler. +
Sets: $CC
, $CCCOM
, $CCFLAGS
, $CFILESUFFIX
, $CFLAGS
, $CPPDEFPREFIX
, $CPPDEFSUFFIX
, $INCPREFIX
, $INCSUFFIX
, $SHCC
, $SHCCCOM
, $SHCCFLAGS
, $SHCFLAGS
, $SHOBJSUFFIX
.
Uses: $_CPPDEFFLAGS
, $_CPPINCFLAGS
.
+Sets construction variables for generic POSIX C copmilers. +
Sets: $CC
, $CCCOM
, $CCFLAGS
, $CFILESUFFIX
, $CFLAGS
, $CPPDEFPREFIX
, $CPPDEFSUFFIX
, $FRAMEWORKPATH
, $FRAMEWORKS
, $INCPREFIX
, $INCSUFFIX
, $SHCC
, $SHCCCOM
, $SHCCFLAGS
, $SHCFLAGS
, $SHOBJSUFFIX
.
Uses: $PLATFORM
.
+Set construction variables for the Clang C compiler. +
Sets: $CC
, $CCVERSION
, $SHCCFLAGS
.
+Set construction variables for the Clang C++ compiler. +
Sets: $CXX
, $CXXVERSION
, $SHCXXFLAGS
, $SHOBJSUFFIX
, $STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME
.
+Sets construction variables for the Compaq Visual Fortran compiler. +
Sets: $FORTRAN
, $FORTRANCOM
, $FORTRANMODDIR
, $FORTRANMODDIRPREFIX
, $FORTRANMODDIRSUFFIX
, $FORTRANPPCOM
, $OBJSUFFIX
, $SHFORTRANCOM
, $SHFORTRANPPCOM
.
Uses: $CPPFLAGS
, $FORTRANFLAGS
, $SHFORTRANFLAGS
, $_CPPDEFFLAGS
, $_FORTRANINCFLAGS
, $_FORTRANMODFLAG
.
+Sets construction variables for generic POSIX C++ compilers. +
Sets: $CPPDEFPREFIX
, $CPPDEFSUFFIX
, $CXX
, $CXXCOM
, $CXXFILESUFFIX
, $CXXFLAGS
, $INCPREFIX
, $INCSUFFIX
, $OBJSUFFIX
, $SHCXX
, $SHCXXCOM
, $SHCXXFLAGS
, $SHOBJSUFFIX
.
Uses: $CXXCOMSTR
.
+Set construction variables for cygwin linker/loader. +
Sets: $IMPLIBPREFIX
, $IMPLIBSUFFIX
, $LDMODULEVERSIONFLAGS
, $LINKFLAGS
, $RPATHPREFIX
, $RPATHSUFFIX
, $SHLIBPREFIX
, $SHLIBSUFFIX
, $SHLIBVERSIONFLAGS
, $SHLINKCOM
, $SHLINKFLAGS
, $_LDMODULEVERSIONFLAGS
, $_SHLIBVERSIONFLAGS
.
+Sets variables by calling a default list of Tool modules +for the platform on which SCons is running. +
+Sets construction variables for D language compiler DMD. +
Sets: $DC
, $DCOM
, $DDEBUG
, $DDEBUGPREFIX
, $DDEBUGSUFFIX
, $DFILESUFFIX
, $DFLAGPREFIX
, $DFLAGS
, $DFLAGSUFFIX
, $DINCPREFIX
, $DINCSUFFIX
, $DLIB
, $DLIBCOM
, $DLIBDIRPREFIX
, $DLIBDIRSUFFIX
, $DLIBFLAGPREFIX
, $DLIBFLAGSUFFIX
, $DLIBLINKPREFIX
, $DLIBLINKSUFFIX
, $DLINK
, $DLINKCOM
, $DLINKFLAGPREFIX
, $DLINKFLAGS
, $DLINKFLAGSUFFIX
, $DPATH
, $DRPATHPREFIX
, $DRPATHSUFFIX
, $DShLibSonameGenerator
, $DVERPREFIX
, $DVERSIONS
, $DVERSUFFIX
, $SHDC
, $SHDCOM
, $SHDLIBVERSION
, $SHDLIBVERSIONFLAGS
, $SHDLINK
, $SHDLINKCOM
, $SHDLINKFLAGS
.
This tool tries to make working with Docbook in SCons a little easier. +It provides several toolchains for creating different output formats, +like HTML or PDF. Contained in the package is +a distribution of the Docbook XSL stylesheets as of version 1.76.1. +As long as you don't specify your own stylesheets for customization, +these official versions are picked as default...which should reduce +the inevitable setup hassles for you. +
Implicit dependencies to images and XIncludes are detected automatically
+if you meet the HTML requirements. The additional
+stylesheet utils/xmldepend.xsl
by Paul DuBois is used for this purpose.
+
Note, that there is no support for XML catalog resolving offered! This tool calls +the XSLT processors and PDF renderers with the stylesheets you specified, that's it. +The rest lies in your hands and you still have to know what you're doing when +resolving names via a catalog. +
For activating the tool "docbook", you have to add its name to the Environment constructor, +like this +
env = Environment(tools=['docbook']) +
On its startup, the Docbook tool tries to find a required xsltproc
processor, and
+a PDF renderer, e.g. fop
. So make sure that these are added to your system's environment
+PATH
and can be called directly, without specifying their full path.
+
For the most basic processing of Docbook to HTML, you need to have installed +
the Python lxml
binding to libxml2
, or
+
the direct Python bindings for libxml2/libxslt
, or
+
a standalone XSLT processor, currently detected are xsltproc
, saxon
, saxon-xslt
+and xalan
.
+
Rendering to PDF requires you to have one of the applications
+fop
or xep
installed.
+
Creating a HTML or PDF document is very simple and straightforward. Say +
env = Environment(tools=['docbook']) +env.DocbookHtml('manual.html', 'manual.xml') +env.DocbookPdf('manual.pdf', 'manual.xml') +
to get both outputs from your XML source manual.xml
. As a shortcut, you can
+give the stem of the filenames alone, like this:
+
env = Environment(tools=['docbook']) +env.DocbookHtml('manual') +env.DocbookPdf('manual') +
and get the same result. Target and source lists are also supported: +
env = Environment(tools=['docbook']) +env.DocbookHtml(['manual.html','reference.html'], ['manual.xml','reference.xml']) +
or even +
env = Environment(tools=['docbook']) +env.DocbookHtml(['manual','reference']) +
Whenever you leave out the list of sources, you may not specify a file extension! The +Tool uses the given names as file stems, and adds the suffixes for target and source files +accordingly. +
The rules given above are valid for the Builders DocbookHtml
,
+DocbookPdf
, DocbookEpub
, DocbookSlidesPdf
and DocbookXInclude
. For the
+DocbookMan
transformation you
+can specify a target name, but the actual output names are automatically
+set from the refname
entries in your XML source.
+
The Builders DocbookHtmlChunked
, DocbookHtmlhelp
and
+DocbookSlidesHtml
are special, in that:
+
they create a large set of files, where the exact names and their number depend +on the content of the source file, and +
the main target is always named index.html
, i.e. the output name for the
+XSL transformation is not picked up by the stylesheets.
+
As a result, there is simply no use in specifying a target HTML name. +So the basic syntax for these builders is always: +
env = Environment(tools=['docbook']) +env.DocbookHtmlhelp('manual') +
If you want to use a specific XSL file, you can set the
+additional xsl
parameter to your
+Builder call as follows:
+
env.DocbookHtml('other.html', 'manual.xml', xsl='html.xsl') +
Since this may get tedious if you always use the same local naming for your customized XSL files,
+e.g. html.xsl
for HTML and pdf.xsl
for PDF output, a set of
+variables for setting the default XSL name is provided. These are:
+
DOCBOOK_DEFAULT_XSL_HTML +DOCBOOK_DEFAULT_XSL_HTMLCHUNKED +DOCBOOK_DEFAULT_XSL_HTMLHELP +DOCBOOK_DEFAULT_XSL_PDF +DOCBOOK_DEFAULT_XSL_EPUB +DOCBOOK_DEFAULT_XSL_MAN +DOCBOOK_DEFAULT_XSL_SLIDESPDF +DOCBOOK_DEFAULT_XSL_SLIDESHTML +
and you can set them when constructing your environment: +
env = Environment(tools=['docbook'], + DOCBOOK_DEFAULT_XSL_HTML='html.xsl', + DOCBOOK_DEFAULT_XSL_PDF='pdf.xsl') +env.DocbookHtml('manual') # now uses html.xsl +
Sets: $DOCBOOK_DEFAULT_XSL_EPUB
, $DOCBOOK_DEFAULT_XSL_HTML
, $DOCBOOK_DEFAULT_XSL_HTMLCHUNKED
, $DOCBOOK_DEFAULT_XSL_HTMLHELP
, $DOCBOOK_DEFAULT_XSL_MAN
, $DOCBOOK_DEFAULT_XSL_PDF
, $DOCBOOK_DEFAULT_XSL_SLIDESHTML
, $DOCBOOK_DEFAULT_XSL_SLIDESPDF
, $DOCBOOK_FOP
, $DOCBOOK_FOPCOM
, $DOCBOOK_FOPFLAGS
, $DOCBOOK_XMLLINT
, $DOCBOOK_XMLLINTCOM
, $DOCBOOK_XMLLINTFLAGS
, $DOCBOOK_XSLTPROC
, $DOCBOOK_XSLTPROCCOM
, $DOCBOOK_XSLTPROCFLAGS
, $DOCBOOK_XSLTPROCPARAMS
.
Uses: $DOCBOOK_FOPCOMSTR
, $DOCBOOK_XMLLINTCOMSTR
, $DOCBOOK_XSLTPROCCOMSTR
.
+Attaches the DVI
builder to the
+construction environment.
+
+Sets construction variables for the dvipdf utility. +
Sets: $DVIPDF
, $DVIPDFCOM
, $DVIPDFFLAGS
.
Uses: $DVIPDFCOMSTR
.
+Sets construction variables for the dvips utility. +
Sets: $DVIPS
, $DVIPSFLAGS
, $PSCOM
, $PSPREFIX
, $PSSUFFIX
.
Uses: $PSCOMSTR
.
+Set construction variables for generic POSIX Fortran 03 compilers. +
Sets: $F03
, $F03COM
, $F03FLAGS
, $F03PPCOM
, $SHF03
, $SHF03COM
, $SHF03FLAGS
, $SHF03PPCOM
, $_F03INCFLAGS
.
Uses: $F03COMSTR
, $F03PPCOMSTR
, $SHF03COMSTR
, $SHF03PPCOMSTR
.
+Set construction variables for generic POSIX Fortran 08 compilers. +
Sets: $F08
, $F08COM
, $F08FLAGS
, $F08PPCOM
, $SHF08
, $SHF08COM
, $SHF08FLAGS
, $SHF08PPCOM
, $_F08INCFLAGS
.
Uses: $F08COMSTR
, $F08PPCOMSTR
, $SHF08COMSTR
, $SHF08PPCOMSTR
.
+Set construction variables for generic POSIX Fortran 77 compilers. +
Sets: $F77
, $F77COM
, $F77FILESUFFIXES
, $F77FLAGS
, $F77PPCOM
, $F77PPFILESUFFIXES
, $FORTRAN
, $FORTRANCOM
, $FORTRANFLAGS
, $SHF77
, $SHF77COM
, $SHF77FLAGS
, $SHF77PPCOM
, $SHFORTRAN
, $SHFORTRANCOM
, $SHFORTRANFLAGS
, $SHFORTRANPPCOM
, $_F77INCFLAGS
.
Uses: $F77COMSTR
, $F77PPCOMSTR
, $FORTRANCOMSTR
, $FORTRANPPCOMSTR
, $SHF77COMSTR
, $SHF77PPCOMSTR
, $SHFORTRANCOMSTR
, $SHFORTRANPPCOMSTR
.
+Set construction variables for generic POSIX Fortran 90 compilers. +
Sets: $F90
, $F90COM
, $F90FLAGS
, $F90PPCOM
, $SHF90
, $SHF90COM
, $SHF90FLAGS
, $SHF90PPCOM
, $_F90INCFLAGS
.
Uses: $F90COMSTR
, $F90PPCOMSTR
, $SHF90COMSTR
, $SHF90PPCOMSTR
.
+Set construction variables for generic POSIX Fortran 95 compilers. +
Sets: $F95
, $F95COM
, $F95FLAGS
, $F95PPCOM
, $SHF95
, $SHF95COM
, $SHF95FLAGS
, $SHF95PPCOM
, $_F95INCFLAGS
.
Uses: $F95COMSTR
, $F95PPCOMSTR
, $SHF95COMSTR
, $SHF95PPCOMSTR
.
+Set construction variables for generic POSIX Fortran compilers. +
Sets: $FORTRAN
, $FORTRANCOM
, $FORTRANFLAGS
, $SHFORTRAN
, $SHFORTRANCOM
, $SHFORTRANFLAGS
, $SHFORTRANPPCOM
.
Uses: $FORTRANCOMSTR
, $FORTRANPPCOMSTR
, $SHFORTRANCOMSTR
, $SHFORTRANPPCOMSTR
.
+Set construction variables for the gXX C++ compiler. +
Sets: $CXX
, $CXXVERSION
, $SHCXXFLAGS
, $SHOBJSUFFIX
.
+Set construction variables for the g77 Fortran compiler.
+Calls the f77
Tool module
+to set variables.
+
+Sets construction variables for the gas assembler.
+Calls the as
module.
+
Sets: $AS
.
+Set construction variables for the gcc C compiler. +
Sets: $CC
, $CCVERSION
, $SHCCFLAGS
.
+Sets construction variables for the D language compiler GDC. +
Sets: $DC
, $DCOM
, $DDEBUG
, $DDEBUGPREFIX
, $DDEBUGSUFFIX
, $DFILESUFFIX
, $DFLAGPREFIX
, $DFLAGS
, $DFLAGSUFFIX
, $DINCPREFIX
, $DINCSUFFIX
, $DLIB
, $DLIBCOM
, $DLIBDIRPREFIX
, $DLIBDIRSUFFIX
, $DLIBFLAGPREFIX
, $DLIBFLAGSUFFIX
, $DLIBLINKPREFIX
, $DLIBLINKSUFFIX
, $DLINK
, $DLINKCOM
, $DLINKFLAGPREFIX
, $DLINKFLAGS
, $DLINKFLAGSUFFIX
, $DPATH
, $DRPATHPREFIX
, $DRPATHSUFFIX
, $DShLibSonameGenerator
, $DVERPREFIX
, $DVERSIONS
, $DVERSUFFIX
, $SHDC
, $SHDCOM
, $SHDLIBVERSION
, $SHDLIBVERSIONFLAGS
, $SHDLINK
, $SHDLINKCOM
, $SHDLINKFLAGS
.
+This is actually a toolset, which supports internationalization and +localization of software being constructed with SCons. The toolset loads +following tools: +
+
+ xgettext
- to extract internationalized messages from source code to
+ POT
file(s),
+
+ msginit
- may be optionally used to initialize PO
+ files,
+
+ msgmerge
- to update PO
files, that already contain
+ translated messages,
+ msgfmt
- to compile textual PO
file to binary
+ installable MO
file.
+
+
+When you enable gettext
, it internally loads all abovementioned tools,
+so you're encouraged to see their individual documentation.
+
+Each of the above tools provides its own builder(s) which may be used to
+perform particular activities related to software internationalization. You
+may be however interested in top-level builder
+Translate
described few paragraphs later.
+
+To use gettext
tools add 'gettext'
tool to your
+environment:
+
+ env = Environment( tools = ['default', 'gettext'] ) +
+Sets construction variables for the GNU F95/F2003 GNU compiler. +
Sets: $F77
, $F90
, $F95
, $FORTRAN
, $SHF77
, $SHF77FLAGS
, $SHF90
, $SHF90FLAGS
, $SHF95
, $SHF95FLAGS
, $SHFORTRAN
, $SHFORTRANFLAGS
.
+Set construction variables for GNU linker/loader. +
Sets: $LDMODULEVERSIONFLAGS
, $RPATHPREFIX
, $RPATHSUFFIX
, $SHLIBVERSIONFLAGS
, $SHLINKFLAGS
, $_LDMODULESONAME
, $_SHLIBSONAME
.
+This Tool sets the required construction variables for working with
+the Ghostscript command. It also registers an appropriate Action
+with the PDF Builder (PDF
), such that the conversion from
+PS/EPS to PDF happens automatically for the TeX/LaTeX toolchain.
+Finally, it adds an explicit Ghostscript Builder (Gs
) to the
+environment.
+
Uses: $GSCOMSTR
.
+Set construction variables for the compilers aCC on HP/UX systems. +
+Set construction variables for the
+aCC on HP/UX systems.
+Calls the cXX
tool for additional variables.
+
Sets: $CXX
, $CXXVERSION
, $SHCXXFLAGS
.
+Sets construction variables for the linker on HP/UX systems. +
Sets: $LINKFLAGS
, $SHLIBSUFFIX
, $SHLINKFLAGS
.
+Sets construction variables for the +icc compiler on OS/2 systems. +
Sets: $CC
, $CCCOM
, $CFILESUFFIX
, $CPPDEFPREFIX
, $CPPDEFSUFFIX
, $CXXCOM
, $CXXFILESUFFIX
, $INCPREFIX
, $INCSUFFIX
.
Uses: $CCFLAGS
, $CFLAGS
, $CPPFLAGS
, $_CPPDEFFLAGS
, $_CPPINCFLAGS
.
+Sets construction variables for the Intel C/C++ compiler.
+Calls the intelc
Tool module to set its variables.
+
+Sets construction variables for the Intel Fortran compiler. +
Sets: $FORTRAN
, $FORTRANCOM
, $FORTRANPPCOM
, $SHFORTRANCOM
, $SHFORTRANPPCOM
.
Uses: $CPPFLAGS
, $FORTRANFLAGS
, $_CPPDEFFLAGS
, $_FORTRANINCFLAGS
.
+Sets construction variables for newer versions +of the Intel Fortran compiler for Linux. +
Sets: $F77
, $F90
, $F95
, $FORTRAN
, $SHF77
, $SHF77FLAGS
, $SHF90
, $SHF90FLAGS
, $SHF95
, $SHF95FLAGS
, $SHFORTRAN
, $SHFORTRANFLAGS
.
+Sets construction variables for the +ilink linker on OS/2 systems. +
Sets: $LIBDIRPREFIX
, $LIBDIRSUFFIX
, $LIBLINKPREFIX
, $LIBLINKSUFFIX
, $LINK
, $LINKCOM
, $LINKFLAGS
.
+Sets construction variables for the Borland +ilink32 linker. +
Sets: $LIBDIRPREFIX
, $LIBDIRSUFFIX
, $LIBLINKPREFIX
, $LIBLINKSUFFIX
, $LINK
, $LINKCOM
, $LINKFLAGS
.
+Sets construction variables for file +and directory installation. +
Sets: $INSTALL
, $INSTALLSTR
.
+Sets construction variables for the Intel C/C++ compiler
+(Linux and Windows, version 7 and later).
+Calls the gcc
or msvc
+(on Linux and Windows, respectively)
+to set underlying variables.
+
Sets: $AR
, $CC
, $CXX
, $INTEL_C_COMPILER_VERSION
, $LINK
.
+Sets construction variables for the jar utility. +
Sets: $JAR
, $JARCOM
, $JARFLAGS
, $JARSUFFIX
.
Uses: $JARCOMSTR
.
+ Sets construction variables for the javac compiler. +
Sets: $JAVABOOTCLASSPATH
, $JAVAC
, $JAVACCOM
, $JAVACFLAGS
, $JAVACLASSPATH
, $JAVACLASSSUFFIX
, $JAVAINCLUDES
, $JAVASOURCEPATH
, $JAVASUFFIX
.
Uses: $JAVACCOMSTR
.
+Sets construction variables for the javah tool. +
Sets: $JAVACLASSSUFFIX
, $JAVAH
, $JAVAHCOM
, $JAVAHFLAGS
.
Uses: $JAVACLASSPATH
, $JAVAHCOMSTR
.
+Sets construction variables for the latex utility. +
Sets: $LATEX
, $LATEXCOM
, $LATEXFLAGS
.
Uses: $LATEXCOMSTR
.
+Sets construction variables for the D language compiler LDC2. +
Sets: $DC
, $DCOM
, $DDEBUG
, $DDEBUGPREFIX
, $DDEBUGSUFFIX
, $DFILESUFFIX
, $DFLAGPREFIX
, $DFLAGS
, $DFLAGSUFFIX
, $DINCPREFIX
, $DINCSUFFIX
, $DLIB
, $DLIBCOM
, $DLIBDIRPREFIX
, $DLIBDIRSUFFIX
, $DLIBFLAGPREFIX
, $DLIBFLAGSUFFIX
, $DLIBLINKPREFIX
, $DLIBLINKSUFFIX
, $DLINK
, $DLINKCOM
, $DLINKFLAGPREFIX
, $DLINKFLAGS
, $DLINKFLAGSUFFIX
, $DPATH
, $DRPATHPREFIX
, $DRPATHSUFFIX
, $DShLibSonameGenerator
, $DVERPREFIX
, $DVERSIONS
, $DVERSUFFIX
, $SHDC
, $SHDCOM
, $SHDLIBVERSION
, $SHDLIBVERSIONFLAGS
, $SHDLINK
, $SHDLINKCOM
, $SHDLINKFLAGS
.
+Sets construction variables for the lex lexical analyser. +
Sets: $LEX
, $LEXCOM
, $LEXFLAGS
.
Uses: $LEXCOMSTR
.
+Sets construction variables for generic POSIX linkers. +
Sets: $LDMODULE
, $LDMODULECOM
, $LDMODULEFLAGS
, $LDMODULENOVERSIONSYMLINKS
, $LDMODULEPREFIX
, $LDMODULESUFFIX
, $LDMODULEVERSION
, $LDMODULEVERSIONFLAGS
, $LIBDIRPREFIX
, $LIBDIRSUFFIX
, $LIBLINKPREFIX
, $LIBLINKSUFFIX
, $LINK
, $LINKCOM
, $LINKFLAGS
, $SHLIBSUFFIX
, $SHLINK
, $SHLINKCOM
, $SHLINKFLAGS
, $__LDMODULEVERSIONFLAGS
, $__SHLIBVERSIONFLAGS
.
Uses: $LDMODULECOMSTR
, $LINKCOMSTR
, $SHLINKCOMSTR
.
+Sets construction variables for the +LinkLoc +linker for the Phar Lap ETS embedded operating system. +
Sets: $LIBDIRPREFIX
, $LIBDIRSUFFIX
, $LIBLINKPREFIX
, $LIBLINKSUFFIX
, $LINK
, $LINKCOM
, $LINKFLAGS
, $SHLINK
, $SHLINKCOM
, $SHLINKFLAGS
.
Uses: $LINKCOMSTR
, $SHLINKCOMSTR
.
+Sets construction variables for the m4 macro processor. +
Uses: $M4COMSTR
.
+Sets construction variables for the Microsoft assembler. +
Sets: $AS
, $ASCOM
, $ASFLAGS
, $ASPPCOM
, $ASPPFLAGS
.
Uses: $ASCOMSTR
, $ASPPCOMSTR
, $CPPFLAGS
, $_CPPDEFFLAGS
, $_CPPINCFLAGS
.
+Sets construction variables for the Microsoft IDL compiler. +
Sets: $MIDL
, $MIDLCOM
, $MIDLFLAGS
.
Uses: $MIDLCOMSTR
.
+Sets construction variables for MinGW (Minimal Gnu on Windows). +
Sets: $AS
, $CC
, $CXX
, $LDMODULECOM
, $LIBPREFIX
, $LIBSUFFIX
, $OBJSUFFIX
, $RC
, $RCCOM
, $RCFLAGS
, $RCINCFLAGS
, $RCINCPREFIX
, $RCINCSUFFIX
, $SHCCFLAGS
, $SHCXXFLAGS
, $SHLINKCOM
, $SHLINKFLAGS
, $SHOBJSUFFIX
, $WINDOWSDEFPREFIX
, $WINDOWSDEFSUFFIX
.
Uses: $RCCOMSTR
, $SHLINKCOMSTR
.
+This scons tool is a part of scons gettext
toolset. It provides scons
+interface to msgfmt(1) command, which generates binary
+message catalog (MO
) from a textual translation description
+(PO
).
+
Sets: $MOSUFFIX
, $MSGFMT
, $MSGFMTCOM
, $MSGFMTCOMSTR
, $MSGFMTFLAGS
, $POSUFFIX
.
Uses: $LINGUAS_FILE
.
+This scons tool is a part of scons gettext
toolset. It provides
+scons interface to msginit(1) program, which creates new
+PO
file, initializing the meta information with values from
+user's environment (or options).
+
Sets: $MSGINIT
, $MSGINITCOM
, $MSGINITCOMSTR
, $MSGINITFLAGS
, $POAUTOINIT
, $POCREATE_ALIAS
, $POSUFFIX
, $POTSUFFIX
, $_MSGINITLOCALE
.
Uses: $LINGUAS_FILE
, $POAUTOINIT
, $POTDOMAIN
.
+This scons tool is a part of scons gettext
toolset. It provides
+scons interface to msgmerge(1) command, which merges two
+Uniform style .po
files together.
+
Sets: $MSGMERGE
, $MSGMERGECOM
, $MSGMERGECOMSTR
, $MSGMERGEFLAGS
, $POSUFFIX
, $POTSUFFIX
, $POUPDATE_ALIAS
.
Uses: $LINGUAS_FILE
, $POAUTOINIT
, $POTDOMAIN
.
+Sets construction variables for the Microsoft +mslib +library archiver. +
Sets: $AR
, $ARCOM
, $ARFLAGS
, $LIBPREFIX
, $LIBSUFFIX
.
Uses: $ARCOMSTR
.
+Sets construction variables for the Microsoft linker. +
Sets: $LDMODULE
, $LDMODULECOM
, $LDMODULEFLAGS
, $LDMODULEPREFIX
, $LDMODULESUFFIX
, $LIBDIRPREFIX
, $LIBDIRSUFFIX
, $LIBLINKPREFIX
, $LIBLINKSUFFIX
, $LINK
, $LINKCOM
, $LINKFLAGS
, $REGSVR
, $REGSVRCOM
, $REGSVRFLAGS
, $SHLINK
, $SHLINKCOM
, $SHLINKFLAGS
, $WIN32DEFPREFIX
, $WIN32DEFSUFFIX
, $WIN32EXPPREFIX
, $WIN32EXPSUFFIX
, $WINDOWSDEFPREFIX
, $WINDOWSDEFSUFFIX
, $WINDOWSEXPPREFIX
, $WINDOWSEXPSUFFIX
, $WINDOWSPROGMANIFESTPREFIX
, $WINDOWSPROGMANIFESTSUFFIX
, $WINDOWSSHLIBMANIFESTPREFIX
, $WINDOWSSHLIBMANIFESTSUFFIX
, $WINDOWS_INSERT_DEF
.
Uses: $LDMODULECOMSTR
, $LINKCOMSTR
, $REGSVRCOMSTR
, $SHLINKCOMSTR
.
+Sets variables for Microsoft Platform SDK and/or Windows SDK.
+Note that unlike most other Tool modules,
+mssdk does not set construction variables,
+but sets the environment variables
+in the environment SCons uses to execute
+the Microsoft toolchain:
+%INCLUDE%
,
+%LIB%
,
+%LIBPATH%
and
+%PATH%
.
+
Uses: $MSSDK_DIR
, $MSSDK_VERSION
, $MSVS_VERSION
.
+Sets construction variables for the Microsoft Visual C/C++ compiler. +
Sets: $BUILDERS
, $CC
, $CCCOM
, $CCFLAGS
, $CCPCHFLAGS
, $CCPDBFLAGS
, $CFILESUFFIX
, $CFLAGS
, $CPPDEFPREFIX
, $CPPDEFSUFFIX
, $CXX
, $CXXCOM
, $CXXFILESUFFIX
, $CXXFLAGS
, $INCPREFIX
, $INCSUFFIX
, $OBJPREFIX
, $OBJSUFFIX
, $PCHCOM
, $PCHPDBFLAGS
, $RC
, $RCCOM
, $RCFLAGS
, $SHCC
, $SHCCCOM
, $SHCCFLAGS
, $SHCFLAGS
, $SHCXX
, $SHCXXCOM
, $SHCXXFLAGS
, $SHOBJPREFIX
, $SHOBJSUFFIX
.
Uses: $CCCOMSTR
, $CXXCOMSTR
, $PCH
, $PCHSTOP
, $PDB
, $SHCCCOMSTR
, $SHCXXCOMSTR
.
+Sets construction variables for Microsoft Visual Studio.
Sets: $MSVSBUILDCOM
, $MSVSCLEANCOM
, $MSVSENCODING
, $MSVSPROJECTCOM
, $MSVSREBUILDCOM
, $MSVSSCONS
, $MSVSSCONSCOM
, $MSVSSCONSCRIPT
, $MSVSSCONSFLAGS
, $MSVSSOLUTIONCOM
.
+Sets construction variables for the Metrowerks CodeWarrior compiler. +
Sets: $CC
, $CCCOM
, $CFILESUFFIX
, $CPPDEFPREFIX
, $CPPDEFSUFFIX
, $CXX
, $CXXCOM
, $CXXFILESUFFIX
, $INCPREFIX
, $INCSUFFIX
, $MWCW_VERSION
, $MWCW_VERSIONS
, $SHCC
, $SHCCCOM
, $SHCCFLAGS
, $SHCFLAGS
, $SHCXX
, $SHCXXCOM
, $SHCXXFLAGS
.
Uses: $CCCOMSTR
, $CXXCOMSTR
, $SHCCCOMSTR
, $SHCXXCOMSTR
.
+Sets construction variables for the Metrowerks CodeWarrior linker. +
Sets: $AR
, $ARCOM
, $LIBDIRPREFIX
, $LIBDIRSUFFIX
, $LIBLINKPREFIX
, $LIBLINKSUFFIX
, $LINK
, $LINKCOM
, $SHLINK
, $SHLINKCOM
, $SHLINKFLAGS
.
+Sets construction variables for the +nasm Netwide Assembler. +
Sets: $AS
, $ASCOM
, $ASFLAGS
, $ASPPCOM
, $ASPPFLAGS
.
Uses: $ASCOMSTR
, $ASPPCOMSTR
.
+Sets construction variables for the Package
Builder.
+
+A framework for building binary and source packages. +
+Sets construction variables for the Portable Document Format builder. +
Sets: $PDFPREFIX
, $PDFSUFFIX
.
+Sets construction variables for the pdflatex utility. +
Sets: $LATEXRETRIES
, $PDFLATEX
, $PDFLATEXCOM
, $PDFLATEXFLAGS
.
Uses: $PDFLATEXCOMSTR
.
+Sets construction variables for the pdftex utility. +
Sets: $LATEXRETRIES
, $PDFLATEX
, $PDFLATEXCOM
, $PDFLATEXFLAGS
, $PDFTEX
, $PDFTEXCOM
, $PDFTEXFLAGS
.
Uses: $PDFLATEXCOMSTR
, $PDFTEXCOMSTR
.
+Sets construction variables for building Qt applications. +
Sets: $QTDIR
, $QT_AUTOSCAN
, $QT_BINPATH
, $QT_CPPPATH
, $QT_LIB
, $QT_LIBPATH
, $QT_MOC
, $QT_MOCCXXPREFIX
, $QT_MOCCXXSUFFIX
, $QT_MOCFROMCXXCOM
, $QT_MOCFROMCXXFLAGS
, $QT_MOCFROMHCOM
, $QT_MOCFROMHFLAGS
, $QT_MOCHPREFIX
, $QT_MOCHSUFFIX
, $QT_UIC
, $QT_UICCOM
, $QT_UICDECLFLAGS
, $QT_UICDECLPREFIX
, $QT_UICDECLSUFFIX
, $QT_UICIMPLFLAGS
, $QT_UICIMPLPREFIX
, $QT_UICIMPLSUFFIX
, $QT_UISUFFIX
.
+Sets construction variables for the rmic utility. +
Sets: $JAVACLASSSUFFIX
, $RMIC
, $RMICCOM
, $RMICFLAGS
.
Uses: $RMICCOMSTR
.
+Sets construction variables for building with RPCGEN. +
Sets: $RPCGEN
, $RPCGENCLIENTFLAGS
, $RPCGENFLAGS
, $RPCGENHEADERFLAGS
, $RPCGENSERVICEFLAGS
, $RPCGENXDRFLAGS
.
+Sets construction variables for the SGI library archiver. +
Sets: $AR
, $ARCOMSTR
, $ARFLAGS
, $LIBPREFIX
, $LIBSUFFIX
, $SHLINK
, $SHLINKFLAGS
.
Uses: $ARCOMSTR
, $SHLINKCOMSTR
.
+Sets construction variables for the SGI C++ compiler. +
Sets: $CXX
, $CXXFLAGS
, $SHCXX
, $SHOBJSUFFIX
.
+Sets construction variables for the SGI C compiler. +
Sets: $CXX
, $SHOBJSUFFIX
.
+Sets construction variables for the SGI linker. +
Sets: $LINK
, $RPATHPREFIX
, $RPATHSUFFIX
, $SHLINKFLAGS
.
+Sets construction variables for the Sun library archiver. +
Sets: $AR
, $ARCOM
, $ARFLAGS
, $LIBPREFIX
, $LIBSUFFIX
.
Uses: $ARCOMSTR
.
+Sets construction variables for the Sun C++ compiler. +
Sets: $CXX
, $CXXVERSION
, $SHCXX
, $SHCXXFLAGS
, $SHOBJPREFIX
, $SHOBJSUFFIX
.
+Sets construction variables for the Sun C compiler. +
Sets: $CXX
, $SHCCFLAGS
, $SHOBJPREFIX
, $SHOBJSUFFIX
.
+Set construction variables for the Sun f77 Fortran compiler. +
Sets: $F77
, $FORTRAN
, $SHF77
, $SHF77FLAGS
, $SHFORTRAN
, $SHFORTRANFLAGS
.
+Set construction variables for the Sun f90 Fortran compiler. +
Sets: $F90
, $FORTRAN
, $SHF90
, $SHF90FLAGS
, $SHFORTRAN
, $SHFORTRANFLAGS
.
+Set construction variables for the Sun f95 Fortran compiler. +
Sets: $F95
, $FORTRAN
, $SHF95
, $SHF95FLAGS
, $SHFORTRAN
, $SHFORTRANFLAGS
.
+Sets construction variables for the Sun linker. +
Sets: $RPATHPREFIX
, $RPATHSUFFIX
, $SHLINKFLAGS
.
+Sets construction variables for the SWIG interface generator. +
Sets: $SWIG
, $SWIGCFILESUFFIX
, $SWIGCOM
, $SWIGCXXFILESUFFIX
, $SWIGDIRECTORSUFFIX
, $SWIGFLAGS
, $SWIGINCPREFIX
, $SWIGINCSUFFIX
, $SWIGPATH
, $SWIGVERSION
, $_SWIGINCFLAGS
.
Uses: $SWIGCOMSTR
.
+Sets construction variables for the tar archiver. +
Sets: $TAR
, $TARCOM
, $TARFLAGS
, $TARSUFFIX
.
Uses: $TARCOMSTR
.
+Sets construction variables for the TeX formatter and typesetter. +
Sets: $BIBTEX
, $BIBTEXCOM
, $BIBTEXFLAGS
, $LATEX
, $LATEXCOM
, $LATEXFLAGS
, $MAKEINDEX
, $MAKEINDEXCOM
, $MAKEINDEXFLAGS
, $TEX
, $TEXCOM
, $TEXFLAGS
.
Uses: $BIBTEXCOMSTR
, $LATEXCOMSTR
, $MAKEINDEXCOMSTR
, $TEXCOMSTR
.
+Set construction variables for the Textfile
and Substfile
builders.
+
Sets: $LINESEPARATOR
, $SUBSTFILEPREFIX
, $SUBSTFILESUFFIX
, $TEXTFILEPREFIX
, $TEXTFILESUFFIX
.
Uses: $SUBST_DICT
.
+Sets construction variables for the Borlan +tib library archiver. +
Sets: $AR
, $ARCOM
, $ARFLAGS
, $LIBPREFIX
, $LIBSUFFIX
.
Uses: $ARCOMSTR
.
+This scons tool is a part of scons gettext
toolset. It provides
+scons interface to xgettext(1)
+program, which extracts internationalized messages from source code. The tool
+provides POTUpdate
builder to make PO
+Template files.
+
Sets: $POTSUFFIX
, $POTUPDATE_ALIAS
, $XGETTEXTCOM
, $XGETTEXTCOMSTR
, $XGETTEXTFLAGS
, $XGETTEXTFROM
, $XGETTEXTFROMPREFIX
, $XGETTEXTFROMSUFFIX
, $XGETTEXTPATH
, $XGETTEXTPATHPREFIX
, $XGETTEXTPATHSUFFIX
, $_XGETTEXTDOMAIN
, $_XGETTEXTFROMFLAGS
, $_XGETTEXTPATHFLAGS
.
Uses: $POTDOMAIN
.
+Sets construction variables for the yacc parse generator. +
Sets: $YACC
, $YACCCOM
, $YACCFLAGS
, $YACCHFILESUFFIX
, $YACCHXXFILESUFFIX
, $YACCVCGFILESUFFIX
.
Uses: $YACCCOMSTR
.
+Sets construction variables for the zip archiver. +
Sets: $ZIP
, $ZIPCOM
, $ZIPCOMPRESSION
, $ZIPFLAGS
, $ZIPSUFFIX
.
Uses: $ZIPCOMSTR
.
+ +This appendix contains descriptions of all of the +function and construction environment methods +in this version of SCons + +
Action(action, [cmd/str/fun, [var, ...]] [option=value, ...])
+ ,
+ env.Action(action, [cmd/str/fun, [var, ...]] [option=value, ...])
+
+Creates an Action object for
+the specified
+action
.
+See the section "Action Objects,"
+below, for a complete explanation of the arguments and behavior.
+
+Note that the
+env.Action
()
+form of the invocation will expand
+construction variables in any argument strings,
+including the
+action
+argument, at the time it is called
+using the construction variables in the
+env
+construction environment through which
+env.Action
()
+was called.
+The
+Action
()
+form delays all variable expansion
+until the Action object is actually used.
+
AddMethod(object, function, [name])
+ ,
+ env.AddMethod(function, [name])
+
+When called with the
+AddMethod
()
+form,
+adds the specified
+function
+to the specified
+object
+as the specified method
+name
.
+When called with the
+env.AddMethod
()
+form,
+adds the specified
+function
+to the construction environment
+env
+as the specified method
+name
.
+In both cases, if
+name
+is omitted or
+None
,
+the name of the
+specified
+function
+itself is used for the method name.
+
+Examples: +
+# Note that the first argument to the function to +# be attached as a method must be the object through +# which the method will be called; the Python +# convention is to call it 'self'. +def my_method(self, arg): + print("my_method() got", arg) + +# Use the global AddMethod() function to add a method +# to the Environment class. This +AddMethod(Environment, my_method) +env = Environment() +env.my_method('arg') + +# Add the function as a method, using the function +# name for the method call. +env = Environment() +env.AddMethod(my_method, 'other_method_name') +env.other_method_name('another arg') +
AddOption(arguments)
+
+This function adds a new command-line option to be recognized.
+The specified
+arguments
+are the same as supported by the standard Python
+optparse.add_option
()
+method (with a few additional capabilities noted below);
+see the documentation for
+optparse
+for a thorough discussion of its option-processing capabities.
+
+In addition to the arguments and values supported by the
+optparse.add_option
()
+method,
+the SCons
+AddOption
+function allows you to set the
+nargs
+keyword value to
+'?'
+(a string with just the question mark)
+to indicate that the specified long option(s) take(s) an
+optional
+argument.
+When
+nargs = '?'
+is passed to the
+AddOption
+function, the
+const
+keyword argument
+may be used to supply the "default"
+value that should be used when the
+option is specified on the command line
+without an explicit argument.
+
+If no
+default=
+keyword argument is supplied when calling
+AddOption
,
+the option will have a default value of
+None
.
+
+Once a new command-line option has been added with
+AddOption
,
+the option value may be accessed using
+GetOption
+or
+env.GetOption
().
+The value may also be set, using
+SetOption
+or
+env.SetOption
(),
+if conditions in a
+SConscript
+require overriding any default value.
+Note, however, that a
+value specified on the command line will
+always
+override a value set by any SConscript file.
+
+Any specified
+help=
+strings for the new option(s)
+will be displayed by the
+-H
+or
+-h
+options
+(the latter only if no other help text is
+specified in the SConscript files).
+The help text for the local options specified by
+AddOption
+will appear below the SCons options themselves,
+under a separate
+Local Options
+heading.
+The options will appear in the help text
+in the order in which the
+AddOption
+calls occur.
+
+Example: +
+AddOption('--prefix', + dest='prefix', + nargs=1, type='string', + action='store', + metavar='DIR', + help='installation prefix') +env = Environment(PREFIX = GetOption('prefix')) +
AddPostAction(target, action)
+ ,
+ env.AddPostAction(target, action)
+
+Arranges for the specified
+action
+to be performed
+after the specified
+target
+has been built.
+The specified action(s) may be
+an Action object, or anything that
+can be converted into an Action object
+(see below).
+
+When multiple targets are supplied, +the action may be called multiple times, +once after each action that generates +one or more targets in the list. +
AddPreAction(target, action)
+ ,
+ env.AddPreAction(target, action)
+
+Arranges for the specified
+action
+to be performed
+before the specified
+target
+is built.
+The specified action(s) may be
+an Action object, or anything that
+can be converted into an Action object
+(see below).
+
+When multiple targets are specified, +the action(s) may be called multiple times, +once before each action that generates +one or more targets in the list. +
+Note that if any of the targets are built in multiple steps,
+the action will be invoked just
+before the "final" action that specifically
+generates the specified target(s).
+For example, when building an executable program
+from a specified source
+.c
+file via an intermediate object file:
+
+foo = Program('foo.c') +AddPreAction(foo, 'pre_action') +
+The specified
+pre_action
+would be executed before
+scons
+calls the link command that actually
+generates the executable program binary
+foo
,
+not before compiling the
+foo.c
+file into an object file.
+
Alias(alias, [targets, [action]])
+ ,
+ env.Alias(alias, [targets, [action]])
+
+Creates one or more phony targets that
+expand to one or more other targets.
+An optional
+action
+(command)
+or list of actions
+can be specified that will be executed
+whenever the any of the alias targets are out-of-date.
+Returns the Node object representing the alias,
+which exists outside of any file system.
+This Node object, or the alias name,
+may be used as a dependency of any other target,
+including another alias.
+Alias
+can be called multiple times for the same
+alias to add additional targets to the alias,
+or additional actions to the list for this alias.
+
+Examples: +
+Alias('install') +Alias('install', '/usr/bin') +Alias(['install', 'install-lib'], '/usr/local/lib') + +env.Alias('install', ['/usr/local/bin', '/usr/local/lib']) +env.Alias('install', ['/usr/local/man']) + +env.Alias('update', ['file1', 'file2'], "update_database $SOURCES") +
AllowSubstExceptions([exception, ...])
+
+Specifies the exceptions that will be allowed
+when expanding construction variables.
+By default,
+any construction variable expansions that generate a
+NameError
+or
+IndexError
+exception will expand to a
+''
+(a null string) and not cause scons to fail.
+All exceptions not in the specified list
+will generate an error message
+and terminate processing.
+
+If
+AllowSubstExceptions
+is called multiple times,
+each call completely overwrites the previous list
+of allowed exceptions.
+
+Example: +
+# Requires that all construction variable names exist. +# (You may wish to do this if you want to enforce strictly +# that all construction variables must be defined before use.) +AllowSubstExceptions() + +# Also allow a string containing a zero-division expansion +# like '${1 / 0}' to evalute to ''. +AllowSubstExceptions(IndexError, NameError, ZeroDivisionError) +
AlwaysBuild(target, ...)
+ ,
+ env.AlwaysBuild(target, ...)
+
+Marks each given
+target
+so that it is always assumed to be out of date,
+and will always be rebuilt if needed.
+Note, however, that
+AlwaysBuild
+does not add its target(s) to the default target list,
+so the targets will only be built
+if they are specified on the command line,
+or are a dependent of a target specified on the command line--but
+they will
+always
+be built if so specified.
+Multiple targets can be passed in to a single call to
+AlwaysBuild
.
+
env.Append(key=val, [...])
+ +Appends the specified keyword arguments +to the end of construction variables in the environment. +If the Environment does not have +the specified construction variable, +it is simply added to the environment. +If the values of the construction variable +and the keyword argument are the same type, +then the two values will be simply added together. +Otherwise, the construction variable +and the value of the keyword argument +are both coerced to lists, +and the lists are added together. +(See also the Prepend method, below.) +
+Example: +
+env.Append(CCFLAGS = ' -g', FOO = ['foo.yyy']) +
env.AppendENVPath(name, newpath, [envname, sep, delete_existing])
+
+This appends new path elements to the given path in the
+specified external environment
+(ENV
+by default).
+This will only add
+any particular path once (leaving the last one it encounters and
+ignoring the rest, to preserve path order),
+and to help assure this,
+will normalize all paths (using
+os.path.normpath
+and
+os.path.normcase
).
+This can also handle the
+case where the given old path variable is a list instead of a
+string, in which case a list will be returned instead of a string.
+
+If
+delete_existing
+is 0, then adding a path that already exists
+will not move it to the end; it will stay where it is in the list.
+
+Example: +
+print 'before:',env['ENV']['INCLUDE'] +include_path = '/foo/bar:/foo' +env.AppendENVPath('INCLUDE', include_path) +print 'after:',env['ENV']['INCLUDE'] + +yields: +before: /foo:/biz +after: /biz:/foo/bar:/foo +
env.AppendUnique(key=val, [...], delete_existing=0)
+ +Appends the specified keyword arguments +to the end of construction variables in the environment. +If the Environment does not have +the specified construction variable, +it is simply added to the environment. +If the construction variable being appended to is a list, +then any value(s) that already exist in the +construction variable will +not +be added again to the list. +However, if delete_existing is 1, +existing matching values are removed first, so +existing values in the arg list move to the end of the list. +
+Example: +
+env.AppendUnique(CCFLAGS = '-g', FOO = ['foo.yyy']) +
BuildDir(build_dir, src_dir, [duplicate])
+ ,
+ env.BuildDir(build_dir, src_dir, [duplicate])
+
+Deprecated synonyms for
+VariantDir
+and
+env.VariantDir
().
+The
+build_dir
+argument becomes the
+variant_dir
+argument of
+VariantDir
+or
+env.VariantDir
().
+
Builder(action, [arguments])
+ ,
+ env.Builder(action, [arguments])
+
+Creates a Builder object for
+the specified
+action
.
+See the section "Builder Objects,"
+below, for a complete explanation of the arguments and behavior.
+
+Note that the
+env.Builder
()
+form of the invocation will expand
+construction variables in any arguments strings,
+including the
+action
+argument,
+at the time it is called
+using the construction variables in the
+env
+construction environment through which
+env.Builder
()
+was called.
+The
+Builder
+form delays all variable expansion
+until after the Builder object is actually called.
+
CacheDir(cache_dir)
+ ,
+ env.CacheDir(cache_dir)
+
+Specifies that
+scons
+will maintain a cache of derived files in
+cache_dir
.
+The derived files in the cache will be shared
+among all the builds using the same
+CacheDir
+call.
+Specifying a
+cache_dir
+of
+None
+disables derived file caching.
+
+Calling
+env.CacheDir
()
+will only affect targets built
+through the specified construction environment.
+Calling
+CacheDir
+sets a global default
+that will be used by all targets built
+through construction environments
+that do
+not
+have an
+env.CacheDir
()
+specified.
+
+When a
+CacheDir
()
+is being used and
+scons
+finds a derived file that needs to be rebuilt,
+it will first look in the cache to see if a
+derived file has already been built
+from identical input files and an identical build action
+(as incorporated into the MD5 build signature).
+If so,
+scons
+will retrieve the file from the cache.
+If the derived file is not present in the cache,
+scons
+will rebuild it and
+then place a copy of the built file in the cache
+(identified by its MD5 build signature),
+so that it may be retrieved by other
+builds that need to build the same derived file
+from identical inputs.
+
+Use of a specified
+CacheDir
+may be disabled for any invocation
+by using the
+--cache-disable
+option.
+
+If the
+--cache-force
+option is used,
+scons
+will place a copy of
+all
+derived files in the cache,
+even if they already existed
+and were not built by this invocation.
+This is useful to populate a cache
+the first time
+CacheDir
+is added to a build,
+or after using the
+--cache-disable
+option.
+
+When using
+CacheDir
,
+scons
+will report,
+"Retrieved `file' from cache,"
+unless the
+--cache-show
+option is being used.
+When the
+--cache-show
+option is used,
+scons
+will print the action that
+would
+have been used to build the file,
+without any indication that
+the file was actually retrieved from the cache.
+This is useful to generate build logs
+that are equivalent regardless of whether
+a given derived file has been built in-place
+or retrieved from the cache.
+
+The
+NoCache
+method can be used to disable caching of specific files. This can be
+useful if inputs and/or outputs of some tool are impossible to
+predict or prohibitively large.
+
Clean(targets, files_or_dirs)
+ ,
+ env.Clean(targets, files_or_dirs)
+
+This specifies a list of files or directories which should be removed
+whenever the targets are specified with the
+-c
+command line option.
+The specified targets may be a list
+or an individual target.
+Multiple calls to
+Clean
+are legal,
+and create new targets or add files and directories to the
+clean list for the specified targets.
+
+Multiple files or directories should be specified
+either as separate arguments to the
+Clean
+method, or as a list.
+Clean
+will also accept the return value of any of the construction environment
+Builder methods.
+Examples:
+
+The related
+NoClean
+function overrides calling
+Clean
+for the same target,
+and any targets passed to both functions will
+not
+be removed by the
+-c
+option.
+
+Examples: +
+Clean('foo', ['bar', 'baz']) +Clean('dist', env.Program('hello', 'hello.c')) +Clean(['foo', 'bar'], 'something_else_to_clean') +
+In this example, +installing the project creates a subdirectory for the documentation. +This statement causes the subdirectory to be removed +if the project is deinstalled. +
+Clean(docdir, os.path.join(docdir, projectname)) +
env.Clone([key=val, ...])
+ +Returns a separate copy of a construction environment. +If there are any keyword arguments specified, +they are added to the returned copy, +overwriting any existing values +for the keywords. +
+Example: +
+env2 = env.Clone() +env3 = env.Clone(CCFLAGS = '-g') +
+Additionally, a list of tools and a toolpath may be specified, as in +the Environment constructor: +
+def MyTool(env): env['FOO'] = 'bar' +env4 = env.Clone(tools = ['msvc', MyTool]) +
+The
+parse_flags
+keyword argument is also recognized:
+
+# create an environment for compiling programs that use wxWidgets +wx_env = env.Clone(parse_flags = '!wx-config --cflags --cxxflags') +
Command(target, source, action, [key=val, ...])
+ ,
+ env.Command(target, source, action, [key=val, ...])
+ +Executes a specific action +(or list of actions) +to build a target file or files. +This is more convenient +than defining a separate Builder object +for a single special-case build. +
+As a special case, the
+source_scanner
+keyword argument can
+be used to specify
+a Scanner object
+that will be used to scan the sources.
+(The global
+DirScanner
+object can be used
+if any of the sources will be directories
+that must be scanned on-disk for
+changes to files that aren't
+already specified in other Builder of function calls.)
+
+Any other keyword arguments specified override any +same-named existing construction variables. +
+An action can be an external command,
+specified as a string,
+or a callable Python object;
+see "Action Objects," below,
+for more complete information.
+Also note that a string specifying an external command
+may be preceded by an
+@
+(at-sign)
+to suppress printing the command in question,
+or by a
+-
+(hyphen)
+to ignore the exit status of the external command.
+
+Examples: +
+env.Command('foo.out', 'foo.in', + "$FOO_BUILD < $SOURCES > $TARGET") + +env.Command('bar.out', 'bar.in', + ["rm -f $TARGET", + "$BAR_BUILD < $SOURCES > $TARGET"], + ENV = {'PATH' : '/usr/local/bin/'}) + +def rename(env, target, source): + import os + os.rename('.tmp', str(target[0])) + +env.Command('baz.out', 'baz.in', + ["$BAZ_BUILD < $SOURCES > .tmp", + rename ]) +
+Note that the
+Command
+function will usually assume, by default,
+that the specified targets and/or sources are Files,
+if no other part of the configuration
+identifies what type of entry it is.
+If necessary, you can explicitly specify
+that targets or source nodes should
+be treated as directoriese
+by using the
+Dir
+or
+env.Dir
()
+functions.
+
+Examples: +
+env.Command('ddd.list', Dir('ddd'), 'ls -l $SOURCE > $TARGET') + +env['DISTDIR'] = 'destination/directory' +env.Command(env.Dir('$DISTDIR')), None, make_distdir) +
+(Also note that SCons will usually +automatically create any directory necessary to hold a target file, +so you normally don't need to create directories by hand.) +
Configure(env, [custom_tests, conf_dir, log_file, config_h])
+ ,
+ env.Configure([custom_tests, conf_dir, log_file, config_h])
+ +Creates a Configure object for integrated +functionality similar to GNU autoconf. +See the section "Configure Contexts," +below, for a complete explanation of the arguments and behavior. +
env.Copy([key=val, ...])
+
+A now-deprecated synonym for
+env.Clone
().
+
Decider(function)
+ ,
+ env.Decider(function)
+
+Specifies that all up-to-date decisions for
+targets built through this construction environment
+will be handled by the specified
+function
.
+The
+function
+can be one of the following strings
+that specify the type of decision function
+to be performed:
+
+
timestamp-newer
+Specifies that a target shall be considered out of date and rebuilt
+if the dependency's timestamp is newer than the target file's timestamp.
+This is the behavior of the classic Make utility,
+and
+make
+can be used a synonym for
+timestamp-newer
.
+
timestamp-match
+Specifies that a target shall be considered out of date and rebuilt +if the dependency's timestamp is different than the +timestamp recorded the last time the target was built. +This provides behavior very similar to the classic Make utility +(in particular, files are not opened up so that their +contents can be checksummed) +except that the target will also be rebuilt if a +dependency file has been restored to a version with an +earlier +timestamp, such as can happen when restoring files from backup archives. +
MD5
+Specifies that a target shall be considered out of date and rebuilt
+if the dependency's content has changed since the last time
+the target was built,
+as determined be performing an MD5 checksum
+on the dependency's contents
+and comparing it to the checksum recorded the
+last time the target was built.
+content
+can be used as a synonym for
+MD5
.
+
MD5-timestamp
+Specifies that a target shall be considered out of date and rebuilt
+if the dependency's content has changed since the last time
+the target was built,
+except that dependencies with a timestamp that matches
+the last time the target was rebuilt will be
+assumed to be up-to-date and
+not
+rebuilt.
+This provides behavior very similar
+to the
+MD5
+behavior of always checksumming file contents,
+with an optimization of not checking
+the contents of files whose timestamps haven't changed.
+The drawback is that SCons will
+not
+detect if a file's content has changed
+but its timestamp is the same,
+as might happen in an automated script
+that runs a build,
+updates a file,
+and runs the build again,
+all within a single second.
+
+
+Examples: +
+# Use exact timestamp matches by default. +Decider('timestamp-match') + +# Use MD5 content signatures for any targets built +# with the attached construction environment. +env.Decider('content') +
+In addition to the above already-available functions,
+the
+function
+argument may be an actual Python function
+that takes the following three arguments:
+
+
dependency
+The Node (file) which
+should cause the
+target
+to be rebuilt
+if it has "changed" since the last tme
+target
+was built.
+
target
+The Node (file) being built.
+In the normal case,
+this is what should get rebuilt
+if the
+dependency
+has "changed."
+
prev_ni
+Stored information about the state of the
+dependency
+the last time the
+target
+was built.
+This can be consulted to match various
+file characteristics
+such as the timestamp,
+size, or content signature.
+
+
+The
+function
+should return a
+True
+(non-zero)
+value if the
+dependency
+has "changed" since the last time
+the
+target
+was built
+(indicating that the target
+should
+be rebuilt),
+and
+False
+(zero)
+otherwise
+(indicating that the target should
+not
+be rebuilt).
+Note that the decision can be made
+using whatever criteria are appopriate.
+Ignoring some or all of the function arguments
+is perfectly normal.
+
+Example: +
+def my_decider(dependency, target, prev_ni): + return not os.path.exists(str(target)) + +env.Decider(my_decider) +
Default(targets)
+ ,
+ env.Default(targets)
+
+This specifies a list of default targets,
+which will be built by
+scons
+if no explicit targets are given on the command line.
+Multiple calls to
+Default
+are legal,
+and add to the list of default targets.
+
+Multiple targets should be specified as
+separate arguments to the
+Default
+method, or as a list.
+Default
+will also accept the Node returned by any
+of a construction environment's
+builder methods.
+
+Examples: +
+Default('foo', 'bar', 'baz') +env.Default(['a', 'b', 'c']) +hello = env.Program('hello', 'hello.c') +env.Default(hello) +
+An argument to
+Default
+of
+None
+will clear all default targets.
+Later calls to
+Default
+will add to the (now empty) default-target list
+like normal.
+
+The current list of targets added using the
+Default
+function or method is available in the
+DEFAULT_TARGETS
+list;
+see below.
+
DefaultEnvironment([args])
+ +Creates and returns a default construction environment object. +This construction environment is used internally by SCons +in order to execute many of the global functions in this list, +and to fetch source files transparently +from source code management systems. +
Depends(target, dependency)
+ ,
+ env.Depends(target, dependency)
+
+Specifies an explicit dependency;
+the
+target
+will be rebuilt
+whenever the
+dependency
+has changed.
+Both the specified
+target
+and
+dependency
+can be a string
+(usually the path name of a file or directory)
+or Node objects,
+or a list of strings or Node objects
+(such as returned by a Builder call).
+This should only be necessary
+for cases where the dependency
+is not caught by a Scanner
+for the file.
+
+Example: +
+env.Depends('foo', 'other-input-file-for-foo') + +mylib = env.Library('mylib.c') +installed_lib = env.Install('lib', mylib) +bar = env.Program('bar.c') + +# Arrange for the library to be copied into the installation +# directory before trying to build the "bar" program. +# (Note that this is for example only. A "real" library +# dependency would normally be configured through the $LIBS +# and $LIBPATH variables, not using an env.Depends() call.) + +env.Depends(bar, installed_lib) +
env.Dictionary([vars])
+ +Returns a dictionary object +containing copies of all of the +construction variables in the environment. +If there are any variable names specified, +only the specified construction +variables are returned in the dictionary. +
+Example: +
+dict = env.Dictionary() +cc_dict = env.Dictionary('CC', 'CCFLAGS', 'CCCOM') +
Dir(name, [directory])
+ ,
+ env.Dir(name, [directory])
+
+This returns a Directory Node,
+an object that represents the specified directory
+name
.
+name
+can be a relative or absolute path.
+directory
+is an optional directory that will be used as the parent directory.
+If no
+directory
+is specified, the current script's directory is used as the parent.
+
+If
+name
+is a list, SCons returns a list of Dir nodes.
+Construction variables are expanded in
+name
.
+
+Directory Nodes can be used anywhere you +would supply a string as a directory name +to a Builder method or function. +Directory Nodes have attributes and methods +that are useful in many situations; +see "File and Directory Nodes," below. +
env.Dump([key])
+
+Returns a pretty printable representation of the environment.
+key
,
+if not
+None
,
+should be a string containing the name of the variable of interest.
+
+This SConstruct: +
+env=Environment() +print env.Dump('CCCOM') +
+will print: +
+'$CC -c -o $TARGET $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS $SOURCES' +
+While this SConstruct: +
+env=Environment() +print env.Dump() +
+will print: +
+{ 'AR': 'ar', + 'ARCOM': '$AR $ARFLAGS $TARGET $SOURCES\n$RANLIB $RANLIBFLAGS $TARGET', + 'ARFLAGS': ['r'], + 'AS': 'as', + 'ASCOM': '$AS $ASFLAGS -o $TARGET $SOURCES', + 'ASFLAGS': [], + ... +
EnsurePythonVersion(major, minor)
+ ,
+ env.EnsurePythonVersion(major, minor)
+
+Ensure that the Python version is at least
+major
.minor
.
+This function will
+print out an error message and exit SCons with a non-zero exit code if the
+actual Python version is not late enough.
+
+Example: +
+EnsurePythonVersion(2,2) +
EnsureSConsVersion(major, minor, [revision])
+ ,
+ env.EnsureSConsVersion(major, minor, [revision])
+
+Ensure that the SCons version is at least
+major.minor
,
+or
+major.minor.revision
.
+if
+revision
+is specified.
+This function will
+print out an error message and exit SCons with a non-zero exit code if the
+actual SCons version is not late enough.
+
+Examples: +
+EnsureSConsVersion(0,14) + +EnsureSConsVersion(0,96,90) +
Environment([key=value, ...])
+ ,
+ env.Environment([key=value, ...])
+
+Return a new construction environment
+initialized with the specified
+key
=
value
+pairs.
+
Execute(action, [strfunction, varlist])
+ ,
+ env.Execute(action, [strfunction, varlist])
+
+Executes an Action object.
+The specified
+action
+may be an Action object
+(see the section "Action Objects,"
+below, for a complete explanation of the arguments and behavior),
+or it may be a command-line string,
+list of commands,
+or executable Python function,
+each of which will be converted
+into an Action object
+and then executed.
+The exit value of the command
+or return value of the Python function
+will be returned.
+
+Note that
+scons
+will print an error message if the executed
+action
+fails--that is,
+exits with or returns a non-zero value.
+scons
+will
+not,
+however,
+automatically terminate the build
+if the specified
+action
+fails.
+If you want the build to stop in response to a failed
+Execute
+call,
+you must explicitly check for a non-zero return value:
+
+Execute(Copy('file.out', 'file.in')) + +if Execute("mkdir sub/dir/ectory"): + # The mkdir failed, don't try to build. + Exit(1) +
Exit([value])
+ ,
+ env.Exit([value])
+
+This tells
+scons
+to exit immediately
+with the specified
+value
.
+A default exit value of
+0
+(zero)
+is used if no value is specified.
+
Export(vars)
+ ,
+ env.Export(vars)
+
+This tells
+scons
+to export a list of variables from the current
+SConscript file to all other SConscript files.
+The exported variables are kept in a global collection,
+so subsequent calls to
+Export
+will over-write previous exports that have the same name.
+Multiple variable names can be passed to
+Export
+as separate arguments or as a list.
+Keyword arguments can be used to provide names and their values.
+A dictionary can be used to map variables to a different name when exported.
+Both local variables and global variables can be exported.
+
+Examples: +
+env = Environment() +# Make env available for all SConscript files to Import(). +Export("env") + +package = 'my_name' +# Make env and package available for all SConscript files:. +Export("env", "package") + +# Make env and package available for all SConscript files: +Export(["env", "package"]) + +# Make env available using the name debug: +Export(debug = env) + +# Make env available using the name debug: +Export({"debug":env}) +
+Note that the
+SConscript
+function supports an
+exports
+argument that makes it easier to to export a variable or
+set of variables to a single SConscript file.
+See the description of the
+SConscript
+function, below.
+
File(name, [directory])
+ ,
+ env.File(name, [directory])
+
+This returns a
+File Node,
+an object that represents the specified file
+name
.
+name
+can be a relative or absolute path.
+directory
+is an optional directory that will be used as the parent directory.
+
+If
+name
+is a list, SCons returns a list of File nodes.
+Construction variables are expanded in
+name
.
+
+File Nodes can be used anywhere you +would supply a string as a file name +to a Builder method or function. +File Nodes have attributes and methods +that are useful in many situations; +see "File and Directory Nodes," below. +
FindFile(file, dirs)
+ ,
+ env.FindFile(file, dirs)
+
+Search for
+file
+in the path specified by
+dirs
.
+dirs
+may be a list of directory names or a single directory name.
+In addition to searching for files that exist in the filesystem,
+this function also searches for derived files
+that have not yet been built.
+
+Example: +
+foo = env.FindFile('foo', ['dir1', 'dir2']) +
FindInstalledFiles()
+ ,
+ env.FindInstalledFiles()
+
+Returns the list of targets set up by the
+Install
+or
+InstallAs
+builders.
+
+This function serves as a convenient method to select the contents of +a binary package. +
+Example: +
+Install( '/bin', [ 'executable_a', 'executable_b' ] ) + +# will return the file node list +# [ '/bin/executable_a', '/bin/executable_b' ] +FindInstalledFiles() + +Install( '/lib', [ 'some_library' ] ) + +# will return the file node list +# [ '/bin/executable_a', '/bin/executable_b', '/lib/some_library' ] +FindInstalledFiles() +
FindPathDirs(variable)
+
+Returns a function
+(actually a callable Python object)
+intended to be used as the
+path_function
+of a Scanner object.
+The returned object will look up the specified
+variable
+in a construction environment
+and treat the construction variable's value as a list of
+directory paths that should be searched
+(like
+$CPPPATH
,
+$LIBPATH
,
+etc.).
+
+Note that use of
+FindPathDirs
+is generally preferable to
+writing your own
+path_function
+for the following reasons:
+1) The returned list will contain all appropriate directories
+found in source trees
+(when
+VariantDir
+is used)
+or in code repositories
+(when
+Repository
+or the
+-Y
+option are used).
+2) scons will identify expansions of
+variable
+that evaluate to the same list of directories as,
+in fact, the same list,
+and avoid re-scanning the directories for files,
+when possible.
+
+Example: +
+def my_scan(node, env, path, arg): + # Code to scan file contents goes here... + return include_files + +scanner = Scanner(name = 'myscanner', + function = my_scan, + path_function = FindPathDirs('MYPATH')) +
FindSourceFiles(node='"."')
+ ,
+ env.FindSourceFiles(node='"."')
+
+Returns the list of nodes which serve as the source of the built files.
+It does so by inspecting the dependency tree starting at the optional
+argument
+node
+which defaults to the '"."'-node. It will then return all leaves of
+node
.
+These are all children which have no further children.
+
+This function is a convenient method to select the contents of a Source +Package. +
+Example: +
+Program( 'src/main_a.c' ) +Program( 'src/main_b.c' ) +Program( 'main_c.c' ) + +# returns ['main_c.c', 'src/main_a.c', 'SConstruct', 'src/main_b.c'] +FindSourceFiles() + +# returns ['src/main_b.c', 'src/main_a.c' ] +FindSourceFiles( 'src' ) +
+As you can see build support files (SConstruct in the above example) +will also be returned by this function. +
Flatten(sequence)
+ ,
+ env.Flatten(sequence)
+ +Takes a sequence (that is, a Python list or tuple) +that may contain nested sequences +and returns a flattened list containing +all of the individual elements in any sequence. +This can be helpful for collecting +the lists returned by calls to Builders; +other Builders will automatically +flatten lists specified as input, +but direct Python manipulation of +these lists does not. +
+Examples: +
+foo = Object('foo.c') +bar = Object('bar.c') + +# Because `foo' and `bar' are lists returned by the Object() Builder, +# `objects' will be a list containing nested lists: +objects = ['f1.o', foo, 'f2.o', bar, 'f3.o'] + +# Passing such a list to another Builder is all right because +# the Builder will flatten the list automatically: +Program(source = objects) + +# If you need to manipulate the list directly using Python, you need to +# call Flatten() yourself, or otherwise handle nested lists: +for object in Flatten(objects): + print str(object) +
GetBuildFailures()
+
+Returns a list of exceptions for the
+actions that failed while
+attempting to build targets.
+Each element in the returned list is a
+BuildError
+object
+with the following attributes
+that record various aspects
+of the build failure:
+
+.node
+The node that was being built
+when the build failure occurred.
+
+.status
+The numeric exit status
+returned by the command or Python function
+that failed when trying to build the
+specified Node.
+
+.errstr
+The SCons error string
+describing the build failure.
+(This is often a generic
+message like "Error 2"
+to indicate that an executed
+command exited with a status of 2.)
+
+.filename
+The name of the file or
+directory that actually caused the failure.
+This may be different from the
+.node
+attribute.
+For example,
+if an attempt to build a target named
+sub/dir/target
+fails because the
+sub/dir
+directory could not be created,
+then the
+.node
+attribute will be
+sub/dir/target
+but the
+.filename
+attribute will be
+sub/dir
.
+
+.executor
+The SCons Executor object
+for the target Node
+being built.
+This can be used to retrieve
+the construction environment used
+for the failed action.
+
+.action
+The actual SCons Action object that failed.
+This will be one specific action
+out of the possible list of
+actions that would have been
+executed to build the target.
+
+.command
+The actual expanded command that was executed and failed,
+after expansion of
+$TARGET
,
+$SOURCE
,
+and other construction variables.
+
+Note that the
+GetBuildFailures
+function
+will always return an empty list
+until any build failure has occurred,
+which means that
+GetBuildFailures
+will always return an empty list
+while the
+SConscript
+files are being read.
+Its primary intended use is
+for functions that will be
+executed before SCons exits
+by passing them to the
+standard Python
+atexit.register
()
+function.
+Example:
+
+import atexit + +def print_build_failures(): + from SCons.Script import GetBuildFailures + for bf in GetBuildFailures(): + print("%s failed: %s" % (bf.node, bf.errstr)) + +atexit.register(print_build_failures) +
GetBuildPath(file, [...])
+ ,
+ env.GetBuildPath(file, [...])
+
+Returns the
+scons
+path name (or names) for the specified
+file
+(or files).
+The specified
+file
+or files
+may be
+scons
+Nodes or strings representing path names.
+
GetLaunchDir()
+ ,
+ env.GetLaunchDir()
+
+Returns the absolute path name of the directory from which
+scons
+was initially invoked.
+This can be useful when using the
+-u
,
+-U
+or
+-D
+options, which internally
+change to the directory in which the
+SConstruct
+file is found.
+
GetOption(name)
+ ,
+ env.GetOption(name)
+
+This function provides a way to query the value of
+SCons options set on scons command line
+(or set using the
+SetOption
+function).
+The options supported are:
+
+
cache_debug
+which corresponds to --cache-debug; +
cache_disable
+which corresponds to --cache-disable; +
cache_force
+which corresponds to --cache-force; +
cache_show
+which corresponds to --cache-show; +
clean
+which corresponds to -c, --clean and --remove; +
config
+which corresponds to --config; +
directory
+which corresponds to -C and --directory; +
diskcheck
+which corresponds to --diskcheck +
duplicate
+which corresponds to --duplicate; +
file
+which corresponds to -f, --file, --makefile and --sconstruct; +
help
+which corresponds to -h and --help; +
ignore_errors
+which corresponds to --ignore-errors; +
implicit_cache
+which corresponds to --implicit-cache; +
implicit_deps_changed
+which corresponds to --implicit-deps-changed; +
implicit_deps_unchanged
+which corresponds to --implicit-deps-unchanged; +
interactive
+which corresponds to --interact and --interactive; +
keep_going
+which corresponds to -k and --keep-going; +
max_drift
+which corresponds to --max-drift; +
no_exec
+which corresponds to -n, --no-exec, --just-print, --dry-run and --recon; +
no_site_dir
+which corresponds to --no-site-dir; +
num_jobs
+which corresponds to -j and --jobs; +
profile_file
+which corresponds to --profile; +
question
+which corresponds to -q and --question; +
random
+which corresponds to --random; +
repository
+which corresponds to -Y, --repository and --srcdir; +
silent
+which corresponds to -s, --silent and --quiet; +
site_dir
+which corresponds to --site-dir; +
stack_size
+which corresponds to --stack-size; +
taskmastertrace_file
+which corresponds to --taskmastertrace; and +
warn
+which corresponds to --warn and --warning. +
+
+See the documentation for the +corresponding command line object for information about each specific +option. +
Glob(pattern, [ondisk, source, strings, exclude])
+ ,
+ env.Glob(pattern, [ondisk, source, strings, exclude])
+
+Returns Nodes (or strings) that match the specified
+pattern
,
+relative to the directory of the current
+SConscript
+file.
+The
+env.Glob
()
+form performs string substition on
+pattern
+and returns whatever matches
+the resulting expanded pattern.
+
+The specified
+pattern
+uses Unix shell style metacharacters for matching:
+
+ * matches everything + ? matches any single character + [seq] matches any character in seq + [!seq] matches any char not in seq +
+If the first character of a filename is a dot, +it must be matched explicitly. +Character matches do +not +span directory separators. +
+The
+Glob
+knows about
+repositories
+(see the
+Repository
+function)
+and source directories
+(see the
+VariantDir
+function)
+and
+returns a Node (or string, if so configured)
+in the local (SConscript) directory
+if matching Node is found
+anywhere in a corresponding
+repository or source directory.
+
+The
+ondisk
+argument may be set to
+False
+(or any other non-true value)
+to disable the search for matches on disk,
+thereby only returning matches among
+already-configured File or Dir Nodes.
+The default behavior is to
+return corresponding Nodes
+for any on-disk matches found.
+
+The
+source
+argument may be set to
+True
+(or any equivalent value)
+to specify that,
+when the local directory is a
+VariantDir
,
+the returned Nodes should be from the
+corresponding source directory,
+not the local directory.
+
+The
+strings
+argument may be set to
+True
+(or any equivalent value)
+to have the
+Glob
+function return strings, not Nodes,
+that represent the matched files or directories.
+The returned strings will be relative to
+the local (SConscript) directory.
+(Note that This may make it easier to perform
+arbitrary manipulation of file names,
+but if the returned strings are
+passed to a different
+SConscript
+file,
+any Node translation will be relative
+to the other
+SConscript
+directory,
+not the original
+SConscript
+directory.)
+
+The
+exclude
+argument may be set to a pattern or a list of patterns
+(following the same Unix shell semantics)
+which must be filtered out of returned elements.
+Elements matching a least one pattern of
+this list will be excluded.
+
+Examples: +
+Program('foo', Glob('*.c')) +Zip('/tmp/everything', Glob('.??*') + Glob('*')) +sources = Glob('*.cpp', exclude=['os_*_specific_*.cpp']) + Glob('os_%s_specific_*.cpp'%currentOS) +
Help(text, append=False)
+ ,
+ env.Help(text, append=False)
+
+This specifies help text to be printed if the
+-h
+argument is given to
+scons
.
+If
+Help
+is called multiple times, the text is appended together in the order that
+Help
+is called. With append set to False, any
+Help
+text generated with
+AddOption
+is clobbered. If append is True, the AddOption help is prepended to the help
+string, thus preserving the
+-h
+message.
+
Ignore(target, dependency)
+ ,
+ env.Ignore(target, dependency)
+ +The specified dependency file(s) +will be ignored when deciding if +the target file(s) need to be rebuilt. +
+You can also use
+Ignore
+to remove a target from the default build.
+In order to do this you must specify the directory the target will
+be built in as the target, and the file you want to skip building
+as the dependency.
+
+Note that this will only remove the dependencies listed from +the files built by default. It will still be built if that +dependency is needed by another object being built. +See the third and forth examples below. +
+Examples: +
+env.Ignore('foo', 'foo.c') +env.Ignore('bar', ['bar1.h', 'bar2.h']) +env.Ignore('.','foobar.obj') +env.Ignore('bar','bar/foobar.obj') +
Import(vars)
+ ,
+ env.Import(vars)
+
+This tells
+scons
+to import a list of variables into the current SConscript file. This
+will import variables that were exported with
+Export
+or in the
+exports
+argument to
+SConscript
.
+Variables exported by
+SConscript
+have precedence.
+Multiple variable names can be passed to
+Import
+as separate arguments or as a list. The variable "*" can be used
+to import all variables.
+
+Examples: +
+Import("env") +Import("env", "variable") +Import(["env", "variable"]) +Import("*") +
Literal(string)
+ ,
+ env.Literal(string)
+
+The specified
+string
+will be preserved as-is
+and not have construction variables expanded.
+
Local(targets)
+ ,
+ env.Local(targets)
+
+The specified
+targets
+will have copies made in the local tree,
+even if an already up-to-date copy
+exists in a repository.
+Returns a list of the target Node or Nodes.
+
env.MergeFlags(arg, [unique])
+
+Merges the specified
+arg
+values to the construction environment's construction variables.
+If the
+arg
+argument is not a dictionary,
+it is converted to one by calling
+env.ParseFlags
+on the argument
+before the values are merged.
+Note that
+arg
+must be a single value,
+so multiple strings must
+be passed in as a list,
+not as separate arguments to
+env.MergeFlags
.
+
+By default,
+duplicate values are eliminated;
+you can, however, specify
+unique=0
+to allow duplicate
+values to be added.
+When eliminating duplicate values,
+any construction variables that end with
+the string
+PATH
+keep the left-most unique value.
+All other construction variables keep
+the right-most unique value.
+
+Examples: +
+# Add an optimization flag to $CCFLAGS. +env.MergeFlags('-O3') + +# Combine the flags returned from running pkg-config with an optimization +# flag and merge the result into the construction variables. +env.MergeFlags(['!pkg-config gtk+-2.0 --cflags', '-O3']) + +# Combine an optimization flag with the flags returned from running pkg-config +# twice and merge the result into the construction variables. +env.MergeFlags(['-O3', + '!pkg-config gtk+-2.0 --cflags --libs', + '!pkg-config libpng12 --cflags --libs']) +
NoCache(target, ...)
+ ,
+ env.NoCache(target, ...)
+
+Specifies a list of files which should
+not
+be cached whenever the
+CacheDir
+method has been activated.
+The specified targets may be a list
+or an individual target.
+
+Multiple files should be specified
+either as separate arguments to the
+NoCache
+method, or as a list.
+NoCache
+will also accept the return value of any of the construction environment
+Builder methods.
+
+Calling
+NoCache
+on directories and other non-File Node types has no effect because
+only File Nodes are cached.
+
+Examples: +
+NoCache('foo.elf') +NoCache(env.Program('hello', 'hello.c')) +
NoClean(target, ...)
+ ,
+ env.NoClean(target, ...)
+
+Specifies a list of files or directories which should
+not
+be removed whenever the targets (or their dependencies)
+are specified with the
+-c
+command line option.
+The specified targets may be a list
+or an individual target.
+Multiple calls to
+NoClean
+are legal,
+and prevent each specified target
+from being removed by calls to the
+-c
+option.
+
+Multiple files or directories should be specified
+either as separate arguments to the
+NoClean
+method, or as a list.
+NoClean
+will also accept the return value of any of the construction environment
+Builder methods.
+
+Calling
+NoClean
+for a target overrides calling
+Clean
+for the same target,
+and any targets passed to both functions will
+not
+be removed by the
+-c
+option.
+
+Examples: +
+NoClean('foo.elf') +NoClean(env.Program('hello', 'hello.c')) +
env.ParseConfig(command, [function, unique])
+
+Calls the specified
+function
+to modify the environment as specified by the output of
+command
.
+The default
+function
+is
+env.MergeFlags
,
+which expects the output of a typical
+*-config
+command
+(for example,
+gtk-config)
+and adds the options
+to the appropriate construction variables.
+By default,
+duplicate values are not
+added to any construction variables;
+you can specify
+unique=0
+to allow duplicate
+values to be added.
+
+Interpreted options
+and the construction variables they affect
+are as specified for the
+env.ParseFlags
+method (which this method calls).
+See that method's description, below,
+for a table of options and construction variables.
+
ParseDepends(filename, [must_exist, only_one])
+ ,
+ env.ParseDepends(filename, [must_exist, only_one])
+
+Parses the contents of the specified
+filename
+as a list of dependencies in the style of
+Make
+or
+mkdep,
+and explicitly establishes all of the listed dependencies.
+
+By default,
+it is not an error
+if the specified
+filename
+does not exist.
+The optional
+must_exist
+argument may be set to a non-zero
+value to have
+scons
+throw an exception and
+generate an error if the file does not exist,
+or is otherwise inaccessible.
+
+The optional
+only_one
+argument may be set to a non-zero
+value to have
+scons
+thrown an exception and
+generate an error
+if the file contains dependency
+information for more than one target.
+This can provide a small sanity check
+for files intended to be generated
+by, for example, the
+gcc -M
+flag,
+which should typically only
+write dependency information for
+one output file into a corresponding
+.d
+file.
+
+The
+filename
+and all of the files listed therein
+will be interpreted relative to
+the directory of the
+SConscript
+file which calls the
+ParseDepends
+function.
+
env.ParseFlags(flags, ...)
+
+Parses one or more strings containing
+typical command-line flags for GCC tool chains
+and returns a dictionary with the flag values
+separated into the appropriate SCons construction variables.
+This is intended as a companion to the
+env.MergeFlags
+method, but allows for the values in the returned dictionary
+to be modified, if necessary,
+before merging them into the construction environment.
+(Note that
+env.MergeFlags
+will call this method if its argument is not a dictionary,
+so it is usually not necessary to call
+env.ParseFlags
+directly unless you want to manipulate the values.)
+
+If the first character in any string is +an exclamation mark (!), +the rest of the string is executed as a command, +and the output from the command is +parsed as GCC tool chain command-line flags +and added to the resulting dictionary. +
+Flag values are translated accordig to the prefix found, +and added to the following construction variables: +
+-arch CCFLAGS, LINKFLAGS +-D CPPDEFINES +-framework FRAMEWORKS +-frameworkdir= FRAMEWORKPATH +-include CCFLAGS +-isysroot CCFLAGS, LINKFLAGS +-I CPPPATH +-l LIBS +-L LIBPATH +-mno-cygwin CCFLAGS, LINKFLAGS +-mwindows LINKFLAGS +-pthread CCFLAGS, LINKFLAGS +-std= CFLAGS +-Wa, ASFLAGS, CCFLAGS +-Wl,-rpath= RPATH +-Wl,-R, RPATH +-Wl,-R RPATH +-Wl, LINKFLAGS +-Wp, CPPFLAGS +- CCFLAGS ++ CCFLAGS, LINKFLAGS +
+Any other strings not associated with options
+are assumed to be the names of libraries
+and added to the
+$LIBS
+construction variable.
+
+Examples (all of which produce the same result): +
+dict = env.ParseFlags('-O2 -Dfoo -Dbar=1') +dict = env.ParseFlags('-O2', '-Dfoo', '-Dbar=1') +dict = env.ParseFlags(['-O2', '-Dfoo -Dbar=1']) +dict = env.ParseFlags('-O2', '!echo -Dfoo -Dbar=1') +
Platform(string)
+
+The
+Platform
+form returns a callable object
+that can be used to initialize
+a construction environment using the
+platform keyword of the
+Environment
+function.
+
+Example: +
+env = Environment(platform = Platform('win32')) +
+The
+env.Platform
+form applies the callable object for the specified platform
+string
+to the environment through which the method was called.
+
+env.Platform('posix') +
+Note that the
+win32
+platform adds the
+SystemDrive
+and
+SystemRoot
+variables from the user's external environment
+to the construction environment's
+$ENV
+dictionary.
+This is so that any executed commands
+that use sockets to connect with other systems
+(such as fetching source files from
+external CVS repository specifications like
+:pserver:anonymous@cvs.sourceforge.net:/cvsroot/scons
)
+will work on Windows systems.
+
Precious(target, ...)
+ ,
+ env.Precious(target, ...)
+
+Marks each given
+target
+as precious so it is not deleted before it is rebuilt. Normally
+scons
+deletes a target before building it.
+Multiple targets can be passed in to a single call to
+Precious
.
+
env.Prepend(key=val, [...])
+ +Appends the specified keyword arguments +to the beginning of construction variables in the environment. +If the Environment does not have +the specified construction variable, +it is simply added to the environment. +If the values of the construction variable +and the keyword argument are the same type, +then the two values will be simply added together. +Otherwise, the construction variable +and the value of the keyword argument +are both coerced to lists, +and the lists are added together. +(See also the Append method, above.) +
+Example: +
+env.Prepend(CCFLAGS = '-g ', FOO = ['foo.yyy']) +
env.PrependENVPath(name, newpath, [envname, sep, delete_existing])
+
+This appends new path elements to the given path in the
+specified external environment
+($ENV
+by default).
+This will only add
+any particular path once (leaving the first one it encounters and
+ignoring the rest, to preserve path order),
+and to help assure this,
+will normalize all paths (using
+os.path.normpath
+and
+os.path.normcase
).
+This can also handle the
+case where the given old path variable is a list instead of a
+string, in which case a list will be returned instead of a string.
+
+If
+delete_existing
+is 0, then adding a path that already exists
+will not move it to the beginning;
+it will stay where it is in the list.
+
+Example: +
+print 'before:',env['ENV']['INCLUDE'] +include_path = '/foo/bar:/foo' +env.PrependENVPath('INCLUDE', include_path) +print 'after:',env['ENV']['INCLUDE'] +
+The above example will print: +
+before: /biz:/foo +after: /foo/bar:/foo:/biz +
env.PrependUnique(key=val, delete_existing=0, [...])
+ +Appends the specified keyword arguments +to the beginning of construction variables in the environment. +If the Environment does not have +the specified construction variable, +it is simply added to the environment. +If the construction variable being appended to is a list, +then any value(s) that already exist in the +construction variable will +not +be added again to the list. +However, if delete_existing is 1, +existing matching values are removed first, so +existing values in the arg list move to the front of the list. +
+Example: +
+env.PrependUnique(CCFLAGS = '-g', FOO = ['foo.yyy']) +
Progress(callable, [interval])
+ ,
+ Progress(string, [interval, file, overwrite])
+ ,
+ Progress(list_of_strings, [interval, file, overwrite])
+ +Allows SCons to show progress made during the build +by displaying a string or calling a function while +evaluating Nodes (e.g. files). +
+If the first specified argument is a Python callable
+(a function or an object that has a
+__call__
()
+method),
+the function will be called
+once every
+interval
+times a Node is evaluated.
+The callable will be passed the evaluated Node
+as its only argument.
+(For future compatibility,
+it's a good idea to also add
+*args
+and
+**kw
+as arguments to your function or method.
+This will prevent the code from breaking
+if SCons ever changes the interface
+to call the function with additional arguments in the future.)
+
+An example of a simple custom progress function +that prints a string containing the Node name +every 10 Nodes: +
+def my_progress_function(node, *args, **kw): + print('Evaluating node %s!' % node) +Progress(my_progress_function, interval=10) +
+A more complicated example of a custom progress display object
+that prints a string containing a count
+every 100 evaluated Nodes.
+Note the use of
+\r
+(a carriage return)
+at the end so that the string
+will overwrite itself on a display:
+
+import sys +class ProgressCounter(object): + count = 0 + def __call__(self, node, *args, **kw): + self.count += 100 + sys.stderr.write('Evaluated %s nodes\r' % self.count) +Progress(ProgressCounter(), interval=100) +
+If the first argument
+Progress
+is a string,
+the string will be displayed
+every
+interval
+evaluated Nodes.
+The default is to print the string on standard output;
+an alternate output stream
+may be specified with the
+file=
+argument.
+The following will print a series of dots
+on the error output,
+one dot for every 100 evaluated Nodes:
+
+import sys +Progress('.', interval=100, file=sys.stderr) +
+If the string contains the verbatim substring
+$TARGET
,
+it will be replaced with the Node.
+Note that, for performance reasons, this is
+not
+a regular SCons variable substition,
+so you can not use other variables
+or use curly braces.
+The following example will print the name of
+every evaluated Node,
+using a
+\r
+(carriage return) to cause each line to overwritten by the next line,
+and the
+overwrite=
+keyword argument to make sure the previously-printed
+file name is overwritten with blank spaces:
+
+import sys +Progress('$TARGET\r', overwrite=True) +
+If the first argument to
+Progress
+is a list of strings,
+then each string in the list will be displayed
+in rotating fashion every
+interval
+evaluated Nodes.
+This can be used to implement a "spinner"
+on the user's screen as follows:
+
+Progress(['-\r', '\\\r', '|\r', '/\r'], interval=5) +
Pseudo(target, ...)
+ ,
+ env.Pseudo(target, ...)
+
+This indicates that each given
+target
+should not be created by the build rule, and if the target is created,
+an error will be generated. This is similar to the gnu make .PHONY
+target. However, in the vast majority of cases, an
+Alias
+is more appropriate.
+
+Multiple targets can be passed in to a single call to
+Pseudo
.
+
PyPackageDir(modulename)
+ ,
+ env.PyPackageDir(modulename)
+
+This returns a Directory Node similar to Dir.
+The python module / package is looked up and if located
+the directory is returned for the location.
+modulename
+Is a named python package / module to
+lookup the directory for it's location.
+
+If
+modulename
+is a list, SCons returns a list of Dir nodes.
+Construction variables are expanded in
+modulename
.
+
env.Replace(key=val, [...])
+ +Replaces construction variables in the Environment +with the specified keyword arguments. +
+Example: +
+env.Replace(CCFLAGS = '-g', FOO = 'foo.xxx') +
Repository(directory)
+ ,
+ env.Repository(directory)
+
+Specifies that
+directory
+is a repository to be searched for files.
+Multiple calls to
+Repository
+are legal,
+and each one adds to the list of
+repositories that will be searched.
+
+To
+scons
,
+a repository is a copy of the source tree,
+from the top-level directory on down,
+which may contain
+both source files and derived files
+that can be used to build targets in
+the local source tree.
+The canonical example would be an
+official source tree maintained by an integrator.
+If the repository contains derived files,
+then the derived files should have been built using
+scons
,
+so that the repository contains the necessary
+signature information to allow
+scons
+to figure out when it is appropriate to
+use the repository copy of a derived file,
+instead of building one locally.
+
+Note that if an up-to-date derived file
+already exists in a repository,
+scons
+will
+not
+make a copy in the local directory tree.
+In order to guarantee that a local copy
+will be made,
+use the
+Local
+method.
+
Requires(target, prerequisite)
+ ,
+ env.Requires(target, prerequisite)
+ +Specifies an order-only relationship +between the specified target file(s) +and the specified prerequisite file(s). +The prerequisite file(s) +will be (re)built, if necessary, +before +the target file(s), +but the target file(s) do not actually +depend on the prerequisites +and will not be rebuilt simply because +the prerequisite file(s) change. +
+Example: +
+env.Requires('foo', 'file-that-must-be-built-before-foo') +
Return([vars..., stop=])
+
+By default,
+this stops processing the current SConscript
+file and returns to the calling SConscript file
+the values of the variables named in the
+vars
+string arguments.
+Multiple strings contaning variable names may be passed to
+Return
.
+Any strings that contain white space
+
+The optional
+stop=
+keyword argument may be set to a false value
+to continue processing the rest of the SConscript
+file after the
+Return
+call.
+This was the default behavior prior to SCons 0.98.
+However, the values returned
+are still the values of the variables in the named
+vars
+at the point
+Return
+is called.
+
+Examples: +
+# Returns without returning a value. +Return() + +# Returns the value of the 'foo' Python variable. +Return("foo") + +# Returns the values of the Python variables 'foo' and 'bar'. +Return("foo", "bar") + +# Returns the values of Python variables 'val1' and 'val2'. +Return('val1 val2') +
Scanner(function, [argument, keys, path_function, node_class, node_factory, scan_check, recursive])
+ ,
+ env.Scanner(function, [argument, keys, path_function, node_class, node_factory, scan_check, recursive])
+
+Creates a Scanner object for
+the specified
+function
.
+See the section "Scanner Objects,"
+below, for a complete explanation of the arguments and behavior.
+
SConscript(scripts, [exports, variant_dir, duplicate, must_exist])
+ ,
+ env.SConscript(scripts, [exports, variant_dir, duplicate, must_exist])
+ ,
+ SConscript(dirs=subdirs, [name=script, exports, variant_dir, duplicate, must_exist])
+ ,
+ env.SConscript(dirs=subdirs, [name=script, exports, variant_dir, duplicate, must_exist])
+
+This tells
+scons
+to execute
+one or more subsidiary SConscript (configuration) files.
+Any variables returned by a called script using
+Return
+will be returned by the call to
+SConscript
.
+There are two ways to call the
+SConscript
+function.
+
+The first way you can call
+SConscript
+is to explicitly specify one or more
+scripts
+as the first argument.
+A single script may be specified as a string;
+multiple scripts must be specified as a list
+(either explicitly or as created by
+a function like
+Split
).
+Examples:
+
+SConscript('SConscript') # run SConscript in the current directory +SConscript('src/SConscript') # run SConscript in the src directory +SConscript(['src/SConscript', 'doc/SConscript']) +config = SConscript('MyConfig.py') +
+The second way you can call
+SConscript
+is to specify a list of (sub)directory names
+as a
+dirs=
subdirs
+keyword argument.
+In this case,
+scons
+will, by default,
+execute a subsidiary configuration file named
+SConscript
+in each of the specified directories.
+You may specify a name other than
+SConscript
+by supplying an optional
+name=
script
+keyword argument.
+The first three examples below have the same effect
+as the first three examples above:
+
+SConscript(dirs='.') # run SConscript in the current directory +SConscript(dirs='src') # run SConscript in the src directory +SConscript(dirs=['src', 'doc']) +SConscript(dirs=['sub1', 'sub2'], name='MySConscript') +
+The optional
+exports
+argument provides a list of variable names or a dictionary of
+named values to export to the
+script(s)
.
+These variables are locally exported only to the specified
+script(s)
,
+and do not affect the global pool of variables used by the
+Export
+function.
+
+The subsidiary
+script(s)
+must use the
+Import
+function to import the variables.
+Examples:
+
+foo = SConscript('sub/SConscript', exports='env') +SConscript('dir/SConscript', exports=['env', 'variable']) +SConscript(dirs='subdir', exports='env variable') +SConscript(dirs=['one', 'two', 'three'], exports='shared_info') +
+If the optional
+variant_dir
+argument is present, it causes an effect equivalent to the
+VariantDir
+method described below.
+(If
+variant_dir
+is not present, the
+
+duplicate
+
+argument is ignored.)
+The
+variant_dir
+
+argument is interpreted relative to the directory of the calling
+SConscript
+file.
+See the description of the
+VariantDir
+function below for additional details and restrictions.
+
+If
+variant_dir
+is present,
+
+the source directory is the directory in which the
+SConscript
+file resides and the
+SConscript
+file is evaluated as if it were in the
+variant_dir
+directory:
+
+SConscript('src/SConscript', variant_dir = 'build') +
+is equivalent to +
+VariantDir('build', 'src') +SConscript('build/SConscript') +
+This later paradigm is often used when the sources are
+in the same directory as the
+SConstruct
:
+
+SConscript('SConscript', variant_dir = 'build') +
+is equivalent to +
+VariantDir('build', '.') +SConscript('build/SConscript') +
+ +
+The optional
+must_exist
+argument, if true, causes an exception to be raised if a requested
+SConscript
file is not found. The current default is false,
+causing only a warning to be omitted, but this behavior is deprecated.
+For scripts which truly intend to be optional, transition to
+explicty supplying
+must_exist=False
to the call.
+
+Here are some composite examples: +
+# collect the configuration information and use it to build src and doc +shared_info = SConscript('MyConfig.py') +SConscript('src/SConscript', exports='shared_info') +SConscript('doc/SConscript', exports='shared_info') +
+# build debugging and production versions. SConscript +# can use Dir('.').path to determine variant. +SConscript('SConscript', variant_dir='debug', duplicate=0) +SConscript('SConscript', variant_dir='prod', duplicate=0) +
+# build debugging and production versions. SConscript +# is passed flags to use. +opts = { 'CPPDEFINES' : ['DEBUG'], 'CCFLAGS' : '-pgdb' } +SConscript('SConscript', variant_dir='debug', duplicate=0, exports=opts) +opts = { 'CPPDEFINES' : ['NODEBUG'], 'CCFLAGS' : '-O' } +SConscript('SConscript', variant_dir='prod', duplicate=0, exports=opts) +
+# build common documentation and compile for different architectures +SConscript('doc/SConscript', variant_dir='build/doc', duplicate=0) +SConscript('src/SConscript', variant_dir='build/x86', duplicate=0) +SConscript('src/SConscript', variant_dir='build/ppc', duplicate=0) +
SConscriptChdir(value)
+ ,
+ env.SConscriptChdir(value)
+
+By default,
+scons
+changes its working directory
+to the directory in which each
+subsidiary SConscript file lives.
+This behavior may be disabled
+by specifying either:
+
+SConscriptChdir(0) +env.SConscriptChdir(0) +
+in which case
+scons
+will stay in the top-level directory
+while reading all SConscript files.
+(This may be necessary when building from repositories,
+when all the directories in which SConscript files may be found
+don't necessarily exist locally.)
+You may enable and disable
+this ability by calling
+SConscriptChdir()
+multiple times.
+
+Example: +
+env = Environment() +SConscriptChdir(0) +SConscript('foo/SConscript') # will not chdir to foo +env.SConscriptChdir(1) +SConscript('bar/SConscript') # will chdir to bar +
SConsignFile([file, dbm_module])
+ ,
+ env.SConsignFile([file, dbm_module])
+
+This tells
+scons
+to store all file signatures
+in the specified database
+file
.
+If the
+file
+name is omitted,
+.sconsign
+is used by default.
+(The actual file name(s) stored on disk
+may have an appropriated suffix appended
+by the
+ dbm_module
.)
+If
+file
+is not an absolute path name,
+the file is placed in the same directory as the top-level
+SConstruct
+file.
+
+If
+file
+is
+None
,
+then
+scons
+will store file signatures
+in a separate
+.sconsign
+file in each directory,
+not in one global database file.
+(This was the default behavior
+prior to SCons 0.96.91 and 0.97.)
+
+The optional
+dbm_module
+argument can be used to specify
+which Python database module
+The default is to use a custom
+SCons.dblite
+module that uses pickled
+Python data structures,
+and which works on all Python versions.
+
+Examples: +
+# Explicitly stores signatures in ".sconsign.dblite" +# in the top-level SConstruct directory (the +# default behavior). +SConsignFile() + +# Stores signatures in the file "etc/scons-signatures" +# relative to the top-level SConstruct directory. +SConsignFile("etc/scons-signatures") + +# Stores signatures in the specified absolute file name. +SConsignFile("/home/me/SCons/signatures") + +# Stores signatures in a separate .sconsign file +# in each directory. +SConsignFile(None) +
env.SetDefault(key=val, [...])
+ +Sets construction variables to default values specified with the keyword +arguments if (and only if) the variables are not already set. +The following statements are equivalent: +
+env.SetDefault(FOO = 'foo') + +if 'FOO' not in env: env['FOO'] = 'foo' +
SetOption(name, value)
+ ,
+ env.SetOption(name, value)
+ +This function provides a way to set a select subset of the scons command +line options from a SConscript file. The options supported are: +
+
clean
+which corresponds to -c, --clean and --remove; +
duplicate
+which corresponds to --duplicate; +
help
+which corresponds to -h and --help; +
implicit_cache
+which corresponds to --implicit-cache; +
max_drift
+which corresponds to --max-drift; +
no_exec
+which corresponds to -n, --no-exec, --just-print, --dry-run and --recon; +
num_jobs
+which corresponds to -j and --jobs; +
random
+which corresponds to --random; and +
silent
+which corresponds to --silent. +
stack_size
+which corresponds to --stack-size. +
+
+See the documentation for the +corresponding command line object for information about each specific +option. +
+Example: +
+SetOption('max_drift', 1) +
SideEffect(side_effect, target)
+ ,
+ env.SideEffect(side_effect, target)
+
+Declares
+side_effect
+as a side effect of building
+target
.
+Both
+side_effect
+and
+target
+can be a list, a file name, or a node.
+A side effect is a target file that is created or updated
+as a side effect of building other targets.
+For example, a Windows PDB
+file is created as a side effect of building the .obj
+files for a static library,
+and various log files are created updated
+as side effects of various TeX commands.
+If a target is a side effect of multiple build commands,
+scons
+will ensure that only one set of commands
+is executed at a time.
+Consequently, you only need to use this method
+for side-effect targets that are built as a result of
+multiple build commands.
+
+Because multiple build commands may update
+the same side effect file,
+by default the
+side_effect
+target is
+not
+automatically removed
+when the
+target
+is removed by the
+-c
+option.
+(Note, however, that the
+side_effect
+might be removed as part of
+cleaning the directory in which it lives.)
+If you want to make sure the
+side_effect
+is cleaned whenever a specific
+target
+is cleaned,
+you must specify this explicitly
+with the
+Clean
+or
+env.Clean
+function.
+
SourceCode(entries, builder)
+ ,
+ env.SourceCode(entries, builder)
+ +This function and its associate factory functions are deprecated. +There is no replacement. +The intended use was to keep a local tree in sync with an archive, +but in actuality the function only causes the archive +to be fetched on the first run. +Synchronizing with the archive is best done external to SCons. +
+Arrange for non-existent source files to
+be fetched from a source code management system
+using the specified
+builder
.
+The specified
+entries
+may be a Node, string or list of both,
+and may represent either individual
+source files or directories in which
+source files can be found.
+
+For any non-existent source files,
+scons
+will search up the directory tree
+and use the first
+SourceCode
+builder it finds.
+The specified
+builder
+may be
+None
,
+in which case
+scons
+will not use a builder to fetch
+source files for the specified
+entries
,
+even if a
+SourceCode
+builder has been specified
+for a directory higher up the tree.
+
+scons
+will, by default,
+fetch files from SCCS or RCS subdirectories
+without explicit configuration.
+This takes some extra processing time
+to search for the necessary
+source code management files on disk.
+You can avoid these extra searches
+and speed up your build a little
+by disabling these searches as follows:
+
+env.SourceCode('.', None) +
+Note that if the specified
+builder
+is one you create by hand,
+it must have an associated
+construction environment to use
+when fetching a source file.
+
+scons
+provides a set of canned factory
+functions that return appropriate
+Builders for various popular
+source code management systems.
+Canonical examples of invocation include:
+
+env.SourceCode('.', env.BitKeeper('/usr/local/BKsources')) +env.SourceCode('src', env.CVS('/usr/local/CVSROOT')) +env.SourceCode('/', env.RCS()) +env.SourceCode(['f1.c', 'f2.c'], env.SCCS()) +env.SourceCode('no_source.c', None) +
+ +
SourceSignatures(type)
+ ,
+ env.SourceSignatures(type)
+
+Note: Although it is not yet officially deprecated,
+use of this function is discouraged.
+See the
+Decider
+function for a more flexible and straightforward way
+to configure SCons' decision-making.
+
+The
+SourceSignatures
+function tells
+scons
+how to decide if a source file
+(a file that is not built from any other files)
+has changed since the last time it
+was used to build a particular target file.
+Legal values are
+MD5
+or
+timestamp
.
+
+If the environment method is used, +the specified type of source signature +is only used when deciding whether targets +built with that environment are up-to-date or must be rebuilt. +If the global function is used, +the specified type of source signature becomes the default +used for all decisions +about whether targets are up-to-date. +
+MD5
+means
+scons
+decides that a source file has changed
+if the MD5 checksum of its contents has changed since
+the last time it was used to rebuild a particular target file.
+
+timestamp
+means
+scons
+decides that a source file has changed
+if its timestamp (modification time) has changed since
+the last time it was used to rebuild a particular target file.
+(Note that although this is similar to the behavior of Make,
+by default it will also rebuild if the dependency is
+older
+than the last time it was used to rebuild the target file.)
+
+There is no different between the two behaviors
+for Python
+Value
+node objects.
+
+MD5
+signatures take longer to compute,
+but are more accurate than
+timestamp
+signatures.
+The default value is
+MD5
.
+
+Note that the default
+TargetSignatures
+setting (see below)
+is to use this
+SourceSignatures
+setting for any target files that are used
+to build other target files.
+Consequently, changing the value of
+SourceSignatures
+will, by default,
+affect the up-to-date decision for all files in the build
+(or all files built with a specific construction environment
+when
+env.SourceSignatures
+is used).
+
Split(arg)
+ ,
+ env.Split(arg)
+ +Returns a list of file names or other objects. +If arg is a string, +it will be split on strings of white-space characters +within the string, +making it easier to write long lists of file names. +If arg is already a list, +the list will be returned untouched. +If arg is any other type of object, +it will be returned as a list +containing just the object. +
+Example: +
+files = Split("f1.c f2.c f3.c") +files = env.Split("f4.c f5.c f6.c") +files = Split(""" + f7.c + f8.c + f9.c +""") +
env.subst(input, [raw, target, source, conv])
+
+Performs construction variable interpolation
+on the specified string or sequence argument
+input
.
+
+By default,
+leading or trailing white space will
+be removed from the result.
+and all sequences of white space
+will be compressed to a single space character.
+Additionally, any
+$(
+and
+$)
+character sequences will be stripped from the returned string,
+The optional
+raw
+argument may be set to
+1
+if you want to preserve white space and
+$(
-$)
+sequences.
+The
+raw
+argument may be set to
+2
+if you want to strip
+all characters between
+any
+$(
+and
+$)
+pairs
+(as is done for signature calculation).
+
+If the input is a sequence +(list or tuple), +the individual elements of +the sequence will be expanded, +and the results will be returned as a list. +
+The optional
+target
+and
+source
+keyword arguments
+must be set to lists of
+target and source nodes, respectively,
+if you want the
+$TARGET
,
+$TARGETS
,
+$SOURCE
+and
+$SOURCES
+to be available for expansion.
+This is usually necessary if you are
+calling
+env.subst
+from within a Python function used
+as an SCons action.
+
+Returned string values or sequence elements
+are converted to their string representation by default.
+The optional
+conv
+argument
+may specify a conversion function
+that will be used in place of
+the default.
+For example, if you want Python objects
+(including SCons Nodes)
+to be returned as Python objects,
+you can use the Python
+Λ
+idiom to pass in an unnamed function
+that simply returns its unconverted argument.
+
+Example: +
+print env.subst("The C compiler is: $CC") + +def compile(target, source, env): + sourceDir = env.subst("${SOURCE.srcdir}", + target=target, + source=source) + +source_nodes = env.subst('$EXPAND_TO_NODELIST', + conv=lambda x: x) +
Tag(node, tags)
+
+Annotates file or directory Nodes with
+information about how the
+Package
+Builder should package those files or directories.
+All tags are optional.
+
+Examples: +
+# makes sure the built library will be installed with 0644 file +# access mode +Tag( Library( 'lib.c' ), UNIX_ATTR="0644" ) + +# marks file2.txt to be a documentation file +Tag( 'file2.txt', DOC ) +
TargetSignatures(type)
+ ,
+ env.TargetSignatures(type)
+
+Note: Although it is not yet officially deprecated,
+use of this function is discouraged.
+See the
+Decider
+function for a more flexible and straightforward way
+to configure SCons' decision-making.
+
+The
+TargetSignatures
+function tells
+scons
+how to decide if a target file
+(a file that
+is
+built from any other files)
+has changed since the last time it
+was used to build some other target file.
+Legal values are
+"build"
;
+"content"
+(or its synonym
+"MD5"
);
+"timestamp"
;
+or
+"source"
.
+
+If the environment method is used, +the specified type of target signature is only used +for targets built with that environment. +If the global function is used, +the specified type of signature becomes the default +used for all target files that +don't have an explicit target signature type +specified for their environments. +
+"content"
+(or its synonym
+"MD5"
)
+means
+scons
+decides that a target file has changed
+if the MD5 checksum of its contents has changed since
+the last time it was used to rebuild some other target file.
+This means
+scons
+will open up
+MD5 sum the contents
+of target files after they're built,
+and may decide that it does not need to rebuild
+"downstream" target files if a file was
+rebuilt with exactly the same contents as the last time.
+
+"timestamp"
+means
+scons
+decides that a target file has changed
+if its timestamp (modification time) has changed since
+the last time it was used to rebuild some other target file.
+(Note that although this is similar to the behavior of Make,
+by default it will also rebuild if the dependency is
+older
+than the last time it was used to rebuild the target file.)
+
+"source"
+means
+scons
+decides that a target file has changed
+as specified by the corresponding
+SourceSignatures
+setting
+("MD5"
+or
+"timestamp"
).
+This means that
+scons
+will treat all input files to a target the same way,
+regardless of whether they are source files
+or have been built from other files.
+
+"build"
+means
+scons
+decides that a target file has changed
+if it has been rebuilt in this invocation
+or if its content or timestamp have changed
+as specified by the corresponding
+SourceSignatures
+setting.
+This "propagates" the status of a rebuilt file
+so that other "downstream" target files
+will always be rebuilt,
+even if the contents or the timestamp
+have not changed.
+
+"build"
+signatures are fastest because
+"content"
+(or
+"MD5"
)
+signatures take longer to compute,
+but are more accurate than
+"timestamp"
+signatures,
+and can prevent unnecessary "downstream" rebuilds
+when a target file is rebuilt to the exact same contents
+as the previous build.
+The
+"source"
+setting provides the most consistent behavior
+when other target files may be rebuilt from
+both source and target input files.
+The default value is
+"source"
.
+
+Because the default setting is
+"source"
,
+using
+SourceSignatures
+is generally preferable to
+TargetSignatures
,
+so that the up-to-date decision
+will be consistent for all files
+(or all files built with a specific construction environment).
+Use of
+TargetSignatures
+provides specific control for how built target files
+affect their "downstream" dependencies.
+
Tool(string, [toolpath, **kw])
+ ,
+ env.Tool(string, [toolpath, **kw])
+
+The
+Tool
+form of the function
+returns a callable object
+that can be used to initialize
+a construction environment using the
+tools keyword of the Environment() method.
+The object may be called with a construction
+environment as an argument,
+in which case the object will
+add the necessary variables
+to the construction environment
+and the name of the tool will be added to the
+$TOOLS
+construction variable.
+
+Additional keyword arguments are passed to the tool's
+generate
()
+method.
+
+Examples: +
+env = Environment(tools = [ Tool('msvc') ]) + +env = Environment() +t = Tool('msvc') +t(env) # adds 'msvc' to the TOOLS variable +u = Tool('opengl', toolpath = ['tools']) +u(env) # adds 'opengl' to the TOOLS variable +
+The
+env.Tool
+form of the function
+applies the callable object for the specified tool
+string
+to the environment through which the method was called.
+
+Additional keyword arguments are passed to the tool's
+generate
()
+method.
+
+env.Tool('gcc') +env.Tool('opengl', toolpath = ['build/tools']) +
Value(value, [built_value])
+ ,
+ env.Value(value, [built_value])
+
+Returns a Node object representing the specified Python value. Value
+Nodes can be used as dependencies of targets. If the result of
+calling
+str
(value
)
+changes between SCons runs, any targets depending on
+Value
(value
)
+will be rebuilt.
+(This is true even when using timestamps to decide if
+files are up-to-date.)
+When using timestamp source signatures, Value Nodes'
+timestamps are equal to the system time when the Node is created.
+
+The returned Value Node object has a
+write
()
+method that can be used to "build" a Value Node
+by setting a new value.
+The optional
+built_value
+argument can be specified
+when the Value Node is created
+to indicate the Node should already be considered
+"built."
+There is a corresponding
+read
()
+method that will return the built value of the Node.
+
+Examples: +
+env = Environment() + +def create(target, source, env): + # A function that will write a 'prefix=$SOURCE' + # string into the file name specified as the + # $TARGET. + f = open(str(target[0]), 'wb') + f.write('prefix=' + source[0].get_contents()) + +# Fetch the prefix= argument, if any, from the command +# line, and use /usr/local as the default. +prefix = ARGUMENTS.get('prefix', '/usr/local') + +# Attach a .Config() builder for the above function action +# to the construction environment. +env['BUILDERS']['Config'] = Builder(action = create) +env.Config(target = 'package-config', source = Value(prefix)) + +def build_value(target, source, env): + # A function that "builds" a Python Value by updating + # the the Python value with the contents of the file + # specified as the source of the Builder call ($SOURCE). + target[0].write(source[0].get_contents()) + +output = env.Value('before') +input = env.Value('after') + +# Attach a .UpdateValue() builder for the above function +# action to the construction environment. +env['BUILDERS']['UpdateValue'] = Builder(action = build_value) +env.UpdateValue(target = Value(output), source = Value(input)) +
VariantDir(variant_dir, src_dir, [duplicate])
+ ,
+ env.VariantDir(variant_dir, src_dir, [duplicate])
+
+Use the
+VariantDir
+function to create a copy of your sources in another location:
+if a name under
+variant_dir
+is not found but exists under
+src_dir
,
+the file or directory is copied to
+variant_dir
.
+Target files can be built in a different directory
+than the original sources by simply refering to the sources (and targets)
+within the variant tree.
+
+VariantDir
+can be called multiple times with the same
+src_dir
+to set up multiple builds with different options
+(variants
).
+The
+src_dir
+location must be in or underneath the SConstruct file's directory, and
+variant_dir
+may not be underneath
+src_dir
.
+
+
+The default behavior is for
+scons
+to physically duplicate the source files in the variant tree.
+Thus, a build performed in the variant tree is guaranteed to be identical
+to a build performed in the source tree even if
+intermediate source files are generated during the build,
+or preprocessors or other scanners search for included files
+relative to the source file,
+or individual compilers or other invoked tools are hard-coded
+to put derived files in the same directory as source files.
+
+If possible on the platform,
+the duplication is performed by linking rather than copying;
+see also the
+--duplicate
+command-line option.
+Moreover, only the files needed for the build are duplicated;
+files and directories that are not used are not present in
+variant_dir
.
+
+Duplicating the source tree may be disabled by setting the
+duplicate
+argument to
+0
+(zero).
+This will cause
+scons
+to invoke Builders using the path names of source files in
+src_dir
+and the path names of derived files within
+variant_dir
.
+This is always more efficient than
+duplicate=1
,
+and is usually safe for most builds
+(but see above for cases that may cause problems).
+
+Note that
+VariantDir
+works most naturally with a subsidiary SConscript file.
+However, you would then call the subsidiary SConscript file
+not in the source directory, but in the
+variant_dir
,
+regardless of the value of
+duplicate
.
+This is how you tell
+scons
+which variant of a source tree to build:
+
+# run src/SConscript in two variant directories +VariantDir('build/variant1', 'src') +SConscript('build/variant1/SConscript') +VariantDir('build/variant2', 'src') +SConscript('build/variant2/SConscript') +
+See also the
+SConscript
+function, described above,
+for another way to specify a variant directory
+in conjunction with calling a subsidiary SConscript file.
+
+Examples: +
+# use names in the build directory, not the source directory +VariantDir('build', 'src', duplicate=0) +Program('build/prog', 'build/source.c') +
+# this builds both the source and docs in a separate subtree +VariantDir('build', '.', duplicate=0) +SConscript(dirs=['build/src','build/doc']) +
+# same as previous example, but only uses SConscript +SConscript(dirs='src', variant_dir='build/src', duplicate=0) +SConscript(dirs='doc', variant_dir='build/doc', duplicate=0) +
WhereIs(program, [path, pathext, reject])
+ ,
+ env.WhereIs(program, [path, pathext, reject])
+
+Searches for the specified executable
+program
,
+returning the full path name to the program
+if it is found,
+and returning None if not.
+Searches the specified
+path
,
+the value of the calling environment's PATH
+(env['ENV']['PATH']
),
+or the user's current external PATH
+(os.environ['PATH']
)
+by default.
+On Windows systems, searches for executable
+programs with any of the file extensions
+listed in the specified
+pathext
,
+the calling environment's PATHEXT
+(env['ENV']['PATHEXT']
)
+or the user's current PATHEXT
+(os.environ['PATHEXT']
)
+by default.
+Will not select any
+path name or names
+in the specified
+reject
+list, if any.
+
+There is a common set of simple tasks that many build configurations rely
+on as they become more complex. Most build tools have special
+purpose constructs for performing these tasks, but since SConscript
+files are Python scripts, you can use more flexible built-in Python
+services to perform these tasks. This appendix lists a number of these
+tasks and how to implement them in Python and SCons.
+
Example E.2. Filename extension substitution
+import os.path +filename = os.path.splitext(filename)[0]+extension +
Example E.3. Appending a path prefix to a list of filenames
+import os.path +filenames = [os.path.join(prefix, x) for x in filenames] +
Example E.4. Substituting a path prefix with another one
+if filename.find(old_prefix) == 0: + filename = filename.replace(old_prefix, new_prefix) +
Example E.5. Filtering a filename list to exclude/retain only a specific set +of extensions
+import os.path +filenames = [x for x in filenames if os.path.splitext(x)[1] in extensions] +
Example E.6. The "backtick function": run a shell command and capture the +output
import subprocess +output = subprocess.check_output(command) +
Example E.7. Generating source code: how code can be generated and used by SCons
+ +The Copy builders here could be any arbitrary shell or python function +that produces one or more files. This example shows how to create +those files and use them in SCons. + +
+#### SConstruct +env = Environment() +env.Append(CPPPATH = "#") + +## Header example +env.Append(BUILDERS = + {'Copy1' : Builder(action = 'cat < $SOURCE > $TARGET', + suffix='.h', src_suffix='.bar')}) +env.Copy1('test.bar') # produces test.h from test.bar. +env.Program('app','main.cpp') # indirectly depends on test.bar + +## Source file example +env.Append(BUILDERS = + {'Copy2' : Builder(action = 'cat < $SOURCE > $TARGET', + suffix='.cpp', src_suffix='.bar2')}) +foo = env.Copy2('foo.bar2') # produces foo.cpp from foo.bar2. +env.Program('app2',['main2.cpp'] + foo) # compiles main2.cpp and foo.cpp into app2. +
+ +Where main.cpp looks like this: + +
+#include "test.h" + +
+produces this: +
% scons -Q
+cat < test.bar > test.h
+cc -o app main.cpp
+cat < foo.bar2 > foo.cpp
+cc -o app2 main2.cpp foo.cpp
+