glib/README.win32

General
=======

For more information about the port or GLib, GTk+ and the GIMP to
native Windows, and pre-built binaries (DLLs), surf to
http://www.gimp.org/win32/ . "Native" means that we use the Win32 API
only, and no POSIX (Unix) emulation layer except that provided by the
Microsoft runtime C library.

To build GLib on Win32, you can use either gcc or the Microsoft
compiler and tools. Both the compiler from MSVC 5.0 and from MSVC 6.0
have been used successfully.

But note that to just *use* GLib on Windows, there is no need to build
it, prebuilt DLLs are available from the webiste above.

The following preprocessor macros are used for conditional compilation
related to Win32:

- G_OS_WIN32 is defined when compiling for Win32, *and* without
  any POSIX emulation, other that to the extent provided by the
  bundled Microsoft C library (msvcrt.dll) and the pthreads-win32
  library. For instance, pathnames are in the native Windows syntax.

- G_WITH_CYGWIN is defined if compiling for the Cygwin
  environment. Note that G_OS_WIN32 is *not* defined in that case, as
  Cygwin is supposed to behave like Unix. G_OS_UNIX *is* defined when
  compiling for Cygwin.

- G_PLATFORM_WIN32 is defined when either G_OS_WIN32 or G_WITH_CYGWIN
  is defined.

The Win32 port of GLib and related software uses only G_OS_WIN32. As
G_OS_WIN32 is defined in glibconfig.h, it is available to all source
files that use GLib (or GTk+, which uses GLib).

Additionally, there are the compiler-specific macros:
- __GNUC__ is defined when using GCC
- _MSC_VER is defined when using the Microsoft compiler

G_OS_WIN32 implies using the Microsoft C runtime MSVCRT.DLL. GLib is
not known to work with the older CRTDLL.DLL runtime, or the static
Microsoft C runtime libraries.

Building software that use GLib or GTk+
=======================================

Even building software that just *use* GLib or GTk+ also require to
have the right compiler set up the right way, so if you intend to use
gcc, follow the relevant instructions below in that case, too.

Libiconv
========

Before building GLib you must also have the libiconv library, either
from the same website mentioned above, or from it's homepage at
http://clisp.cons.org/~haible/packages-libiconv.html. Libiconv has
makefiles for building with MS Visual C only, but as it is one source
file only, building it "by hand" with gcc isn't hard.

Where are the makefiles?
========================

If you are building from a CVS snapshot, you will not have any
makefile.mingw or makefile.msc file. You should copy the corresponding
makefile.mingw.in or makefile.msc.in file to that name, and edit the
@GLIB_VERSION@ strings to the correct version number.

This is done automatically when an official GLib source distribution
package is built.

Building GLib with gcc
======================

I use the latest gcc, gcc-2.95.3. Version 2.95.2 will most probably
also work.

You can either use gcc running on Cygwin, or the "pure" mingw
gcc. Using the latter is much easier. 

Just fetch the latest version of gcc for mingw and the msvcrt runtime,
from www.mingw.org.

Set up your PATH so that the gcc from the bin directory that got
created above is the one that gets used. Even if you run the mingw
gcc, you still want to have Cygwin to run make in.

Then run make -f makefile.mingw. 

I use the -fnative-struct flag, which means that in order to use the
prebuilt DLLs (especially of GTK+), you *must* also use that flag.
(This flag means that the struct layout is identical to that used by
MSVC. This is essential if the same DLLs are to be usable both from
gcc- and MSVC-compiled code, which definitely is a good thing.)

It is also possible to use the auto*, ./configure and libtool
mechanism when building for mingw. You should be running Cygwin, or
maybe cross-compiling from real Unix, for the configure script to
work, obviously. The same libtool issue has to be taken into account
as when building for Cygwin: You most probably should have a very new
libtool. Remember to invoke configure with CC='gcc -fnative-struct' if
you want to produce DLLs binary compatible with the "official" ones.

But please note that the ./configure mechanism should not blindly be
used to build a GLib to be distributed to potential developers because
it produces a compiler-dependent glibconfig.h (and config.h, but that
shouldn't matter). For instance, the typedef for gint64 is long long
with gcc, but __int64 with MSVC. Otherwise, there really shouldn't be
any reason to distribute separate GLib DLLs for gcc and MSVC users, as
both compiler+tools generate code that uses the same C runtime
library. Thus one either has to edit glibconfig.h afterwards, or use
the hand-written config.h.win32 and glibconfig.h.win32.

There are probably also other hickups when using auto* and configure
to build for mingw, sigh. Every now and then I try to get rid of the
hand-written makefiles and configuration headers for Win32, and start
fooling around with auto* etc, but after a while give up and fall
back. At least, it used to be like that. Lately I have again been
working on using auto*/configure/libtool on Win32, and it now seems to
work well enough (with some patches applied to the current CVS
libtool...).

The hand-written makefile.mingw(.in) files, and the stuff in the
"build" module has been updated to produce DLLs and import libraries
that match what Makefile.am and libtool produces.

If you want to run the Cygwin-based gcc, it gets a bit more
complicated. We still want gcc to produce code that does not use
Cygwin, but the msvcrt runtime. In theory it should work to use the
-no-cygwin flag, but I haven't tested that lately.

If you would want to use the Cygwin tools to generate a GLib that
*does* use the Cygwin runtime, the normal Unix configuration method
should work as if on Unix. Note that successfully producing shared
libraries (DLLs) most probably requires you to have a very new
libtool. (And a new libtool probably requires rather new autoconf and
automake.)

Building with MSVC
==================

If using the Microsoft toolchain, build with `nmake -f
makefile.msc`.

--Tor Lillqvist <tml@iki.fi>