glib/docs/reference/gobject/glib-mkenums.xml

<refentry id="glib-mkenums" lang="en">

<refentryinfo>
  <title>gdbus</title>
  <productname>GObject</productname>
  <authorgroup>
    <author>
      <contrib>Developer</contrib>
      <firstname>Owen</firstname>
      <surname>Taylor</surname>
    </author>
  </authorgroup>
</refentryinfo>

<refmeta>
<refentrytitle>glib-mkenums</refentrytitle>
<manvolnum>1</manvolnum>
<refmiscinfo class="manual">User Commands</refmiscinfo>
</refmeta>

<refnamediv>
<refname>glib-mkenums</refname>
<refpurpose>C language enum description generation utility</refpurpose>
</refnamediv>

<refsynopsisdiv>
<cmdsynopsis>
<command>glib-mkenums</command>
<arg choice="opt" rep="repeat">OPTION</arg>
<arg choice="opt" rep="repeat">FILE</arg>
</cmdsynopsis>
</refsynopsisdiv>

<refsect1><title>Description</title>
<para><command>glib-mkenums</command> is a small perl-script utility that
parses C code to extract enum definitions and produces enum descriptions based
on text templates specified by the user. Most frequently this script is used to
produce C code that contains enum values as strings so programs can provide
value name strings for introspection.
</para>

<para><command>glib-mkenums</command> takes a list of valid C code files as
input. The options specified control the text that is output, certain
substitutions are performed on the text templates for keywords enclosed
in @ characters.
</para>

<refsect2><title>Production text substitutions</title>
<para>
Certain keywords enclosed in @ characters will be substituted in the
emitted text. For the substitution examples of the keywords below,
the following example enum definition is assumed:
<informalexample><programlisting>
typedef enum
{
  PREFIX_THE_XVALUE    = 1 &lt;&lt; 3,
  PREFIX_ANOTHER_VALUE = 1 &lt;&lt; 4
} PrefixTheXEnum;
</programlisting></informalexample>
<variablelist>
<varlistentry>
<term>@EnumName@</term>
<listitem><para>
The name of the enum currently being processed, enum names are assumed to be
properly namespaced and to use mixed capitalization to separate
words (e.g. PrefixTheXEnum).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@enum_name@</term>
<listitem><para>
The enum name with words lowercase and word-separated by underscores
(e.g. prefix_the_xenum).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@ENUMNAME@</term>
<listitem><para>
The enum name with words uppercase and word-separated by underscores
(e.g. PREFIX_THE_XENUM).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@ENUMSHORT@</term>
<listitem><para>
The enum name with words uppercase and word-separated by underscores,
prefix stripped (e.g. THE_XENUM).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@ENUMPREFIX@</term>
<listitem><para>
The prefix of the enum name (e.g. PREFIX).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@VALUENAME@</term>
<listitem><para>
The enum value name currently being processed with words uppercase and
word-separated by underscores,
this is the assumed literal notation of enum values in the C sources
(e.g. PREFIX_THE_XVALUE).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@valuenick@</term>
<listitem><para>
A nick name for the enum value currently being processed, this is usually
generated by stripping common prefix words of all the enum values of the
current enum, the words are lowercase and underscores are substituted by a
minus (e.g. the-xvalue).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@valuenum@</term>
<listitem><para>
The integer value for the enum value currently being processed.  This is
calculated by using <command>perl</command> to attempt to evaluate the
expression as it appears in the C source code.  If evaluation fails then
<command>glib-mkenums</command> will exit with an error status, but this
only happens if <literal>@valuenum@</literal> appears in your value
production template.  (Since: 2.26)
</para></listitem>
</varlistentry>

<varlistentry>
<term>@type@</term>
<listitem><para>
This is substituted either by "enum" or "flags", depending on whether the
enum value definitions contained bit-shift operators or not (e.g. flags).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@Type@</term>
<listitem><para>
The same as <literal>@type@</literal> with the first letter capitalized (e.g. Flags).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@TYPE@</term>
<listitem><para>
The same as <literal>@type@</literal> with all letters uppercased (e.g. FLAGS).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@filename@</term>
<listitem><para>
The name of the input file currently being processed (e.g. foo.h).
</para></listitem>
</varlistentry>

<varlistentry>
<term>@basename@</term>
<listitem><para>
The base name of the input file currently being processed (e.g. foo.h). (Since: 2.22)
</para></listitem>
</varlistentry>
</variablelist>
</para>
</refsect2>
<refsect2><title>Trigraph extensions</title>
<para>
Some C comments are treated specially in the parsed enum definitions,
such comments start out with the trigraph sequence <literal>/*&lt;</literal>
and end with the trigraph sequence <literal>&gt;*/</literal>.
Per enum definition, the options "skip" and "flags" can be specified, to
indicate this enum definition to be skipped, or for it to be treated as
a flags definition, or to specify the common prefix to be stripped from
all values to generate value nicknames, respectively. The "underscore_name"
option can be used to specify the word separation used in the *_get_type()
function. For instance, /*&lt; underscore_name=gnome_vfs_uri_hide_options &gt;*/.
</para>
<para>
Per value definition, the options "skip" and "nick" are supported.
The former causes the value to be skipped, and the latter can be used to
specify the otherwise auto-generated nickname.
Examples:
<informalexample><programlisting>
typedef enum /*&lt; skip &gt;*/
{
  PREFIX_FOO
} PrefixThisEnumWillBeSkipped;
typedef enum /*&lt; flags,prefix=PREFIX &gt;*/
{
  PREFIX_THE_ZEROTH_VALUE,	/*&lt; skip &gt;*/
  PREFIX_THE_FIRST_VALUE,
  PREFIX_THE_SECOND_VALUE,
  PREFIX_THE_THIRD_VALUE,	/*&lt; nick=the-last-value &gt;*/
} PrefixTheFlagsEnum;
</programlisting></informalexample>
</para>
</refsect2>
</refsect1>

<refsect1><title>Options</title>
<variablelist>

<varlistentry>
<term><option>--fhead</option> <replaceable>TEXT</replaceable></term>
<listitem><para>
Emits <replaceable>TEXT</replaceable> prior to processing input files.
</para>
<para>
You can specify this option multiple times, and the <replaceable>TEXT</replaceable>
will be concatenated.
</para>
<para>
When used along with a template file, <replaceable>TEXT</replaceable>
will be prepended to the template's <literal>file-header</literal> section.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--fprod</option> <replaceable>TEXT</replaceable></term>
<listitem><para>
Emits <replaceable>TEXT</replaceable> every time a new input file
is being processed.
</para>
<para>
You can specify this option multiple times, and the <replaceable>TEXT</replaceable>
will be concatenated.
</para>
<para>
When used along with a template file, <replaceable>TEXT</replaceable>
will be appended to the template's <literal>file-production</literal> section.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--ftail</option> <replaceable>TEXT</replaceable></term>
<listitem><para>
Emits <replaceable>TEXT</replaceable> after all input files have been
processed.
</para>
<para>
You can specify this option multiple times, and the <replaceable>TEXT</replaceable>
will be concatenated.
</para>
<para>
When used along with a template file, <replaceable>TEXT</replaceable>
will be appended to the template's <literal>file-tail</literal> section.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--eprod</option> <replaceable>TEXT</replaceable></term>
<listitem><para>
Emits <replaceable>TEXT</replaceable> everytime an enum is encountered
in the input files.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--vhead</option> <replaceable>TEXT</replaceable></term>
<listitem><para>
Emits <replaceable>TEXT</replaceable> before iterating over the set of
values of an enum.
</para>
<para>
You can specify this option multiple times, and the <replaceable>TEXT</replaceable>
will be concatenated.
</para>
<para>
When used along with a template file, <replaceable>TEXT</replaceable>
will be prepended to the template's <literal>value-header</literal> section.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--vprod</option> <replaceable>TEXT</replaceable></term>
<listitem><para>
Emits <replaceable>TEXT</replaceable> for every value of an enum.
</para>
<para>
You can specify this option multiple times, and the <replaceable>TEXT</replaceable>
will be concatenated.
</para>
<para>
When used along with a template file, <replaceable>TEXT</replaceable>
will be appended to the template's <literal>value-production</literal> section.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--vtail</option> <replaceable>TEXT</replaceable></term>
<listitem><para>
Emits <replaceable>TEXT</replaceable> after iterating over all values
of an enum.
</para>
<para>
You can specify this option multiple times, and the <replaceable>TEXT</replaceable>
will be concatenated.
</para>
<para>
When used along with a template file, <replaceable>TEXT</replaceable>
will be appended to the template's <literal>value-tail</literal> section.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--comments</option> <replaceable>TEXT</replaceable></term>
<listitem><para>
Template for auto-generated comments, the default (for C code generations) is
<literal>"/* @comment@ */"</literal>.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--template</option> <replaceable>FILE</replaceable></term>
<listitem><para>
Read templates from the given file. The templates are enclosed in
specially-formatted C comments
<informalexample><programlisting>
/*** BEGIN section ***/
/*** END section ***/
</programlisting></informalexample>
where section may be <literal>file-header</literal>,
<literal>file-production</literal>, <literal>file-tail</literal>,
<literal>enumeration-production</literal>, <literal>value-header</literal>,
<literal>value-production</literal>, <literal>value-tail</literal> or
<literal>comment</literal>.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--identifier-prefix</option> <replaceable>PREFIX</replaceable></term>
<listitem><para>
Indicates what portion of the enum name should be intepreted as the
prefix (eg, the "<literal>Gtk</literal>" in
"<literal>GtkDirectionType</literal>"). Normally this will be figured
out automatically, but you may need to override the default if your
namespace is capitalized oddly.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--symbol-prefix</option> <replaceable>PREFIX</replaceable></term>
<listitem><para>
Indicates what prefix should be used to correspond to the identifier
prefix in related C function names (eg, the "<literal>gtk</literal>"
in "<literal>gtk_direction_type_get_type</literal>". Equivalently,
this is the lowercase version of the prefix component of the enum
value names (eg, the "<literal>GTK</literal>" in
"<literal>GTK_DIR_UP</literal>". The default value is the identifier
prefix, converted to lowercase.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--help</option></term>
<listitem><para>
Print brief help and exit.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--version</option></term>
<listitem><para>
Print version and exit.
</para></listitem>
</varlistentry>

<varlistentry>
<term><option>--output=FILE</option></term>
<listitem><para>
Write output to FILE instead of stdout.
</para></listitem>
</varlistentry>

</variablelist>
</refsect1>

<refsect1><title>Using glib-mkenums with Autotools</title>
<para>
In order to use <command>glib-mkenums</command> in your project when using
Autotools as the build system, you will first need to modify your
<filename>configure.ac</filename> file to ensure you find the appropriate
command using <command>pkg-config</command>, similarly as to how you discover
the compiler and linker flags for GLib.
</para>
<informalexample><programlisting>
PKG_PROG_PKG_CONFIG([0.28])

PKG_CHECK_VAR([GLIB_MKENUMS], [glib-2.0], [glib_mkenums])
</programlisting></informalexample>
<para>
In your <filename>Makefile.am</filename> file you will typically use rules
like these:
</para>
<informalexample><programlisting>
# A list of headers to inspect
project_headers = \
        project-foo.h \
        project-bar.h \
        project-baz.h

enum-types.h: $(project_headers) enum-types.h.in
        $(AM_V_GEN)$(GLIB_MKENUMS) \
                --template=enum-types.h.in \
                --output=$@ \
                $(project_headers)

enum-types.c: $(project_headers) enum-types.c.in enum-types.h
        $(AM_V_GEN)$(GLIB_MKENUMS) \
                --template=enum-types.c.in \
                --output=$@ \
                $(project_headers)

BUILT_SOURCES += enum-types.h enum-types.c
CLEANFILES += enum-types.h enum-types.c
EXTRA_DIST += enum-types.h.in enum-types.c.in
</programlisting></informalexample>
<para>
In the example above, we have a variable called <literal>project_headers</literal>
where we reference all header files we want to inspect for generating enumeration
GTypes. In the <filename>enum-types.h</filename> rule we use <command>glib-mkenums</command>
with a template called <filename>enum-types.h.in</filename> in order to generate the
header file; a header template file will typically look like this:
</para>
<informalexample><programlisting>
/*** BEGIN file-header ***/
#pragma once

/* Include the main project header */
#include "project.h"

G_BEGIN_DECLS
/*** END file-header ***/

/*** BEGIN file-production ***/

/* enumerations from "@filename@" */
/*** END file-production ***/

/*** BEGIN value-header ***/
GType @enum_name@_get_type (void) G_GNUC_CONST;
#define @ENUMPREFIX@_TYPE_@ENUMSHORT@ (@enum_name@_get_type ())
/*** END value-header ***/

/*** BEGIN file-tail ***/
G_END_DECLS
/*** END file-tail ***/
</programlisting></informalexample>
<para>
The <filename>enum-types.c</filename> rule is similar to the rule for the
header file, but will use a different <filename>enum-types.c.in</filename> template
file, similar to this:
</para>
<informalexample><programlisting>
/*** BEGIN file-header ***/
#include "config.h"
#include "enum-types.h"

/*** END file-header ***/

/*** BEGIN file-production ***/
/* enumerations from "@filename@" */
/*** END file-production ***/

/*** BEGIN value-header ***/
GType
@enum_name@_get_type (void)
{
  static volatile gsize g_@type@_type_id__volatile;

  if (g_once_init_enter (&amp;g_define_type_id__volatile))
    {
      static const G@Type@Value values[] = {
/*** END value-header ***/

/*** BEGIN value-production ***/
            { @VALUENAME@, "@VALUENAME@", "@valuenick@" },
/*** END value-production ***/

/*** BEGIN value-tail ***/
            { 0, NULL, NULL }
      };

      GType g_@type@_type_id =
        g_@type@_register_static (g_intern_static_string ("@EnumName@"), values);

      g_once_init_leave (&amp;g_@type@_type_id__volatile, g_@type@_type_id);
    }
  return g_@type@_type_id__volatile;
}

/*** END value-tail ***/
</programlisting></informalexample>
</refsect1>

<refsect1><title>See also</title>
<para>
<citerefentry>
<refentrytitle>glib-genmarshal</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry>
</para>
</refsect1>
</refentry>