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<book id="index" lang="en-GB">
  <bookinfo>
    <title>GTK-Doc Manual</title>
    <edition>1.24.1</edition>
    <abstract role="description"><para>User manual for developers with instructions on GTK-Doc usage.</para></abstract>
    <authorgroup>
      <author>
        <firstname>Chris</firstname>
        <surname>Lyttle</surname>
        <affiliation>
          <address>
            <email>chris@wilddev.net</email>
          </address>
        </affiliation>
      </author>
      <author>
        <firstname>Dan</firstname>
        <surname>Mueth</surname>
        <affiliation>
          <address>
            <email>d-mueth@uchicago.edu</email>
          </address>
        </affiliation>
      </author>
      <author>
        <firstname>Stefan</firstname>
        <surname>Sauer (Kost)</surname>
        <affiliation>
          <address>
            <email>ensonic@users.sf.net</email>
          </address>
        </affiliation>
      </author>
    </authorgroup>
    <publisher role="maintainer">
      <publishername>GTK-Doc project</publishername>
      <address><email>gtk-doc-list@gnome.org</email></address>
    </publisher>
    <copyright>
      <year>2000, 2005</year>
      <holder>Dan Mueth and Chris Lyttle</holder>
    </copyright>
    <copyright>
      <year>2007-2019</year>
      <holder>Stefan Sauer (Kost)</holder>
    </copyright>

    <!-- translators: uncomment this:
    <copyright>
      <year>2000</year>
      <holder>ME-THE-TRANSLATOR (Latin translation)</holder>
    </copyright>
    -->

    <legalnotice>
      <para>Permission is granted to copy, distribute and/or modify this document under the terms of the <citetitle>GNU Free Documentation Licence</citetitle>, Version 1.1 or any later version published by the Free Software Foundation with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the licence is <link linkend="fdl">included</link>.</para>
      <para>Many of the names used by companies to distinguish their products and services are claimed as trademarks. Where those names appear in any GNOME documentation, and those trademarks are made aware to the members of the GNOME Documentation Project, the names have been printed in caps or initial caps.</para>
    </legalnotice>

    <revhistory>
      <revision>
         <revnumber>1.32</revnumber>
         <date>15 Aug 2019</date>
         <authorinitials>ss</authorinitials>
         <revremark>hotfix release</revremark>
      </revision>
      <revision>
         <revnumber>1.31</revnumber>
         <date>05 Aug 2019</date>
         <authorinitials>ss</authorinitials>
         <revremark>refactorings and more test coverage</revremark>
      </revision>
      <revision>
         <revnumber>1.30</revnumber>
         <date>08 May 2019</date>
         <authorinitials>ss</authorinitials>
         <revremark>more test coverage</revremark>
      </revision>
      <revision>
         <revnumber>1.29</revnumber>
         <date>28 Aug 2018</date>
         <authorinitials>ss</authorinitials>
         <revremark>bug fixes</revremark>
      </revision>
      <revision>
         <revnumber>1.28</revnumber>
         <date>24 Mar 2018</date>
         <authorinitials>ss</authorinitials>
         <revremark>bug fixes</revremark>
      </revision>
      <revision>
         <revnumber>1.27</revnumber>
         <date>07 Dec 2017</date>
         <authorinitials>ss</authorinitials>
         <revremark>fine tuning of the python port</revremark>
      </revision>
      <revision>
         <revnumber>1.26</revnumber>
         <date>11 Aug 2017</date>
         <authorinitials>ss</authorinitials>
         <revremark>port all tools from perl/bash to python</revremark>
      </revision>
      <revision>
        <revnumber>1.25</revnumber>
        <date>21 March 2016</date>
        <authorinitials>ss</authorinitials>
        <revremark>bug fixes, test cleanups</revremark>
      </revision>
      <revision>
        <revnumber>1.24</revnumber>
        <date>29 May 2015</date>
        <authorinitials>ss</authorinitials>
        <revremark>bug fix</revremark>
      </revision>
      <revision>
        <revnumber>1.23</revnumber>
        <date>17 May 2015</date>
        <authorinitials>ss</authorinitials>
        <revremark>bug fix</revremark>
      </revision>
      <revision>
        <revnumber>1.22</revnumber>
        <date>07 May 2015</date>
        <authorinitials>ss</authorinitials>
        <revremark>bug fixes, dropping deprecated features</revremark>
      </revision>
      <revision>
        <revnumber>1.21</revnumber>
        <date>17 Jul 2014</date>
        <authorinitials>ss</authorinitials>
        <revremark>bug fixes, dropping deprecated features</revremark>
      </revision>
      <revision>
        <revnumber>1.20</revnumber>
        <date>16 Feb 2014</date>
        <authorinitials>ss</authorinitials>
        <revremark>bug fixes, markdown support, style improvements</revremark>
      </revision>
      <revision>
        <revnumber>1.19</revnumber>
        <date>05 Jun 2013</date>
        <authorinitials>ss</authorinitials>
        <revremark>bug fixes</revremark>
      </revision>
      <revision>
        <revnumber>1.18</revnumber>
        <date>14 Sep 2011</date>
        <authorinitials>ss</authorinitials>
        <revremark>bug fixes, speedups, markdown support</revremark>
      </revision>
      <revision>
        <revnumber>1.17</revnumber>
        <date>26 Feb 2011</date>
        <authorinitials>sk</authorinitials>
        <revremark>urgent bug fix update</revremark>
      </revision>
      <revision>
        <revnumber>1.16</revnumber>
        <date>14 Jan 2011</date>
        <authorinitials>sk</authorinitials>
        <revremark>bugfixes, layout improvements</revremark>
      </revision>
      <revision>
        <revnumber>1.15</revnumber>
        <date>21 May 2010</date>
        <authorinitials>sk</authorinitials>
        <revremark>bug and regression fixes</revremark>
      </revision>
      <revision>
        <revnumber>1.14</revnumber>
        <date>28 March 2010</date>
        <authorinitials>sk</authorinitials>
        <revremark>bugfixes and performance improvements</revremark>
      </revision>
      <revision>
        <revnumber>1.13</revnumber>
        <date>18 December 2009</date>
        <authorinitials>sk</authorinitials>
        <revremark>broken tarball update</revremark>
      </revision>
      <revision>
        <revnumber>1.12</revnumber>
        <date>18 December 2009</date>
        <authorinitials>sk</authorinitials>
        <revremark>new tool features and bugfixes</revremark>
      </revision>
      <revision>
        <revnumber>1.11</revnumber>
        <date>16 November 2008</date>
        <authorinitials>mal</authorinitials>
        <revremark>GNOME doc-utils migration</revremark>
      </revision>
    </revhistory>

  </bookinfo>

  <!-- ======== Chapter 1: Introduction ======================== -->

  <chapter id="introduction">
    <title>Introduction</title>

    <para>This chapter introduces GTK-Doc and gives an overview of what it is and how it is used.</para>

    <sect1 id="whatisgtkdoc">
      <title>What is GTK-Doc?</title>

      <para>GTK-Doc is used to document C code. It is typically used to document the public API of libraries, such as the GTK+ and GNOME libraries, but it can also be used to document application code.</para>
    </sect1>

    <sect1 id="howdoesgtkdocwork">
      <title>How Does GTK-Doc Work?</title>

      <para>GTK-Doc works by using documentation of functions placed inside the source files in specially-formatted comment blocks, or documentation added to the template files which GTK-Doc uses (though note that GTK-Doc will only document functions that are declared in header files; it won't produce output for static functions).</para>

      <para>
        GTK-Doc consists of a number of python scripts, each performing a different step
        in the process.
      </para>

      <para>There are 5 main steps in the process:</para>

      <orderedlist>

        <listitem>
          <para>
            <guilabel>Writing the documentation.</guilabel>

            The author fills in the source files with the documentation for each
            function, macro, structs or unions, etc.
          </para>
        </listitem>

        <listitem>
          <para>
            <guilabel>Gathering information about the code.</guilabel>

            <application>gtkdoc-scan</application> scans the header files of the
            code looking for declarations of functions, macros, enums, structs, and unions.
            It creates the file <filename>&lt;module&gt;-decl-list.txt</filename> containing a list of the
            declarations, placing them into sections according to which header file they
            are in. On the first run this file is copied to <filename>&lt;module&gt;-sections.txt</filename>.
            The author can rearrange the sections, and the order of the
            declarations within them, to produce the final desired order.
            The second file it generates is <filename>&lt;module&gt;-decl.txt</filename>.
            This file contains the full declarations found by the scanner. If for
            some reason one would like some symbols to show up in the docs, where
            the full declaration cannot be found by the scanner or the declaration
            should appear differently, one can place entities similar to the ones in
            <filename>&lt;module&gt;-decl.txt</filename> into <filename>&lt;module&gt;-overrides.txt</filename>.
         </para>
         <para>
            <application>gtkdoc-scangobj</application> can also be used to dynamically query a library about
            any GObject subclasses it exports. It saves information about each
            object's position in the class hierarchy and about any GObject properties
            and signals it provides.
          </para>
         <para>
            <application>gtkdoc-scanobj</application> should not be used anymore.
            It was needed in the past when GObject was still GtkObject inside gtk+.
         </para>
        </listitem>

        <listitem>
          <para>
            <guilabel>Generating the XML and HTML/PDF.</guilabel>

            <application>gtkdoc-mkdb</application> turns the template files into
            XML files in the <filename class="directory">xml/</filename> subdirectory.
            If the source code contains documentation on functions, using the
            special comment blocks, it gets merged in here. If there are no tmpl files used
            it only reads docs from sources and introspection data.
          </para>
          <para>
            <application>gtkdoc-mkhtml</application> turns the XML files into HTML
            files in the <filename class="directory">html/</filename> subdirectory.
            Likewise <application>gtkdoc-mkpdf</application> turns the XML files into a PDF
            document called <filename>&lt;package&gt;.pdf</filename>.
          </para>
          <para>
            Files in <filename class="directory">xml/</filename> and
            <filename class="directory">html/</filename> directories are always
            overwritten. One should never edit them directly.
          </para>
        </listitem>

        <listitem>
          <para><guilabel>Fixing up cross-references between documents.</guilabel> After installing the HTML files, <application>gtkdoc-fixxref</application> can be run to fix up any cross-references between separate documents. For example, the GTK+ documentation contains many cross-references to types documented in the GLib manual. When creating the source tarball for distribution, <application>gtkdoc-rebase</application> turns all external links into web-links. When installing distributed (pre-generated) docs the same application will try to turn links back to local links (where those docs are installed).</para>
        </listitem>
      </orderedlist>

    </sect1>

    <sect1 id="gettinggtkdoc">
      <title>Getting GTK-Doc</title>

      <sect2 id="requirements">
        <title>Requirements</title>
        <para>
          <guilabel>python 2/3</guilabel> - the main scripts are written in python.
        </para>
        <para>
          <guilabel>xsltproc</guilabel> - the xslt processor from libxslt
          <ulink url="http://xmlsoft.org/XSLT/" type="http">xmlsoft.org/XSLT/</ulink>
        </para>
        <para>
          <guilabel>docbook-xsl</guilabel> - the docbook xsl stylesheets
          <ulink url="http://sourceforge.net/projects/docbook/files/docbook-xsl/" type="http">sourceforge.net/projects/docbook/files/docbook-xsl</ulink>
        </para>
        <para>
          One of <guilabel>source-highlight</guilabel>, <guilabel>highlight</guilabel> or
          <guilabel>vim</guilabel> - optional - used for syntax highlighting of examples
        </para>
      </sect2>
    </sect1>

    <sect1 id="aboutgtkdoc">
      <title>About GTK-Doc</title>

      <para>
        Historically GTK-Doc was used to generate template files from the sources
        code. These template files could be used by developers to enter the
        API documentation. This approach was rather inconvenient because it
        required to keep the generated files under version control.
        Since GTK-Doc 1.9 it became possible to place all API information
        into source comments, which made the template support obsolete.
        In version 1.26 template support has been removed.
      </para>

      <para>(FIXME)</para>

      <para>
        (authors, web pages, mailing list, license, future plans,
        comparison with other similar systems.)
      </para>

    </sect1>

    <sect1 id="aboutthismanual">
      <title>About this Manual</title>

      <para>(FIXME)</para>

      <para>(who it is meant for, where you can get it, licence)</para>

    </sect1>

  </chapter>

  <chapter id="settingup">
    <title>Project Setup</title>

    <para>
      This Chapter describes the steps that are necessary to integrate GTK-Doc
      into your project. The integration of GTK-Doc into a project includes the
      following steps:
    </para>

    <itemizedlist>
      <listitem>
        <para>
          Preparation of the directory structure and creating required
          configuration files for your GTK-Doc documentation (see
          <link linkend="settingup_docfiles">
            Setting up a skeleton documentation</link>).
        </para>
      </listitem>
      <listitem>
        <para>
          Adjusting the build system to build your documentation using the
          GTK-Doc tools. Multiple build systems are supported, in
          this manual we describe how to integrate GTK-Doc with
          <link linkend="settingup_autotools">Autotools</link>,
          <link linkend="settingup_cmake">CMake</link>, and
          <link linkend="settingup_plain_makefiles">plain Makefiles</link>.
        </para>
      </listitem>
      <listitem>
        <para>
          Adding GTK-Doc specific files to version control and deciding which
          files to ignore (see <link linkend="settingup_vcs">
            Integration with version control systems</link>).
        </para>
      </listitem>
    </itemizedlist>

    <para>
      The following sections assume we work on a project called
      <code>meep</code>.
      This project contains two packages (or modules),
      a library called <code>libmeep</code> and an end-user app
      called <code>meeper</code>.
    </para>

    <sect1 id="settingup_docfiles">
      <title>Setting up a skeleton documentation</title>

      <para>
        A common convention is to place documentation into a folder called
        <code>docs</code> inside your top-level project directory.
        We usually distinguish between <emphasis>reference
        documentation</emphasis> intended for developers and an
        <emphasis>user manual</emphasis> intended for end-users.
        Again the convention is to have separate folders for both.
        We usually place the reference documentation in a folder named
        <code>reference</code> and the end-user manual in a folder named
        <code>help</code> as.

        According to the above convention the documentation for our
        <code>libmeep</code> package would be placed into:
        <code>docs/reference/libmeep</code>.

        For packages with just one library or application
        the documentation could also be placed directly into
        <code>docs/reference</code>.

        It is not mandatory to use the above convention, but if you
        choose to use a different directory structure you must adjust
        your build system configuration to match your directory
        structure.
      </para>

      <para>
        In the following sections we will assume a directory structure
        for our <emphasis>meep</emphasis> project that uses the above
        conventions.

        <example>
          <title>Example directory structure of <emphasis>meep</emphasis>
            project</title>
          <programlisting><![CDATA[
meep/
  docs/
    reference/  # reference documentation
      libmeep/
      meeper/
    help/       # optional: user manual
      meeper/
  src/
    libmeep/
    meeper/
]]></programlisting>
        </example>
      </para>
    </sect1>

    <sect1 id="settingup_autotools">
      <title>Integration with Autotools</title>
      <para>
        Integration of GTK-Doc into an autotools-based build system requires the
        following steps:
      </para>
      <itemizedlist>
        <listitem>
          <para>
            Ensure that <application>gtkdocize</application> is run once before
            the <filename>configure</filename> script. If an
            <filename>autogen.sh</filename> script is present, adjust it to
            check for GTK-Doc and add a call to
            <application>gtkdocize</application>.
          </para>

          <para>
            The main purpose of <application>gtkdocize</application> is to
            make the <filename>gtk-doc.make</filename> Makefile and the
            <filename>gtk-doc.m4</filename> macro definition file available
            to the build system, either by copying or linking it
            into the project.
          </para>
        </listitem>
        <listitem>
          <para>
            Add the necessary <application>autoconf</application> macros to
            <filename>configure.ac</filename> to enable GTK-Doc in your build
            system to allow configuration of GTK-Doc via the generated
            <filename>configure</filename> script.
          </para>
          <para>
            Among others with registers the <code>--enable-gtk-doc</code>
            option with the <filename>configure</filename> script.
          </para>
        </listitem>
        <listitem>
          <para>
            Create an <application>automake</application> script for each
            application or library in your project. In the example used in this
            documentation this step applies to both <code>meeper</code> and
            <code>libmeep</code>.
          </para>
        </listitem>
      </itemizedlist>

      <para>
        In the following sections, we will perform the above steps in reverse
        order. We start with the <application>automake</application> scripts
        and work our way up to <filename>configure.ac</filename> and
        <filename>autogen.sh</filename>.
        Then we show how enable Gtk-Doc in the build system and
        how to build the documentation.
      </para>

      <sect2 id="settingup_automake">
        <title>Integration with automake</title>

        <para>
          First copy the <filename>Makefile.am</filename> from the
          <filename class="directory">examples</filename> sub-directory of the
          <ulink url="https://gitlab.gnome.org/GNOME/gtk-doc/raw/master/examples/Makefile.am">
            gtkdoc-sources</ulink>
          to your project's reference documentation directory (e.g.
          <filename class="directory">docs/reference/&lt;package&gt;</filename>).
          A local copy should be available under e.g.
          <filename>/usr/share/doc/gtk-doc-tools/examples/Makefile.am</filename>.
          If you have multiple packages repeat this for each one.
        </para>

        <note>
          <simpara>
            Do not forget to add each <filename>Makefile.am</filename>
            to the <function>AC_CONFIG_FILES</function> macro in
            <filename>configure.ac</filename>. For
            <filename>docs/reference/libmeep/Makefile.am</filename> you will
            need to add the entry
            <filename>docs/reference/libmeep/Makefile</filename>
            to <function>AC_CONFIG_FILES</function>.
          </simpara>
        </note>

        <example>
          <title>
            Example directory structure with <filename>Makefiles.am</filename>
          </title>
          <programlisting>
meep/
  docs/
    reference/  # reference documentation
      libmeep/
        Makefile.am
      meeper/
        Makefile.am
    help/       # optional: user manual
      meeper/
  src/
    libmeep/
    meeper/
</programlisting>
        </example>

        <para>
          Next, you need to customize the copied Makefiles
          and provide values for the various parameters in each
          <filename>Makefile.am</filename>.

          All settings have a comment above them that describes their purpose
          and how to customize the setting.

          Most settings are used to supply extra flags to the respective tools
          to which they apply. Every tool
          has a variable of the form <option>&lt;TOOLNAME&gt;_OPTIONS</option>
          (e.g. the tool <application>gtkdoc-mkhtml</application> has
          an option named <code>MKHTML_OPTIONS</code>).

          All the tools support <option>--help</option> to list the supported
          options.
        </para>

        <para>
          The following list explains the most relevant options. Check the
          example <filename>Makefile.am</filename> for additional options.

          <itemizedlist>
            <listitem>
              <para>
                <option>DOC_MODULE</option> is used to provide the name of the
                package that is being documentated (e.g. <code>meeper</code>, or
                <code>libmeep</code>).
              </para>
            </listitem>
            <listitem>
              <para>
                <option>DOC_SOURCE_DIR</option>
                is used to specify the location
                of source directory which GTK-Doc searches for your API
                documentation. This will usually be
                <code>
                  DOC_SOURCE_DIR=$(top_srcdir)/src
                </code>
                or a sub-directory of that directory.
              </para>
            </listitem>

            <listitem>
              <para>
                <option>HFILE_GLOB</option>
                and
                <option>CFILE_GLOB</option>
                are used for dependencies. Each option take a file-glob (e.g.
                <code>HFILE_GLOB=$(top_srcdir)/src/*.c</code>).
                The documentation will be rebuilt if any of the matched files
                change.
              </para>
            </listitem>

            <listitem>
              <para>
                <option>EXTRA_HFILES</option>
                allows to specify extra header files
                to include when scanning for API documentation, which are not
                found under <code>DOC_SOURCE_DIR</code> (e.g. <code>
                EXTRA_HFILES=$(top_srcdir}/contrib/extra.h</code>).
              </para>
            </listitem>

            <listitem>
              <para>
                <option>IGNORE_HFILES</option>
                allows to specify header files
                or directories to ignore when scanning for API documentation.
                Use the basename of the file or directory (e.g. <code>
                IGNORE_HFILES=gtkdebug.h gtkintl.h private_code_folder</code>).
              </para>
            </listitem>

            <listitem>
              <para>
                <option>HTML_IMAGES</option>
                allows to specify images files which
                will be copied into the <filename>html/</filename> directory of
                the generated documentation.
                If your API documentation includes any images they need to be
                added to this
                option (e.g. <code>
                HTML_IMAGES=$(top_srcdir)/gtk/stock-icons/stock_about_24.png</code>).
              </para>
            </listitem>

            <listitem>
              <para>
                <option>content_files</option>
                allows to specify extra files
                that are included by
                <code>$(DOC_MAIN_SGML_FILE)</code>
                (e.g. <code>
                content_files=running.xml building.xml changes-2.0.xml</code>).
              </para>
            </listitem>

            <listitem>
              <para>
                <option>expand_content_files</option>
                allows to specify files
                where <emphasis>gtk-doc abbreviations</emphasis> such as
                <code>#GtkWidget</code>
                are expanded (e.g. <code>
                expand_content_files=running.xml</code>).
              </para>
            </listitem>
          </itemizedlist>
        </para>

      </sect2>

      <sect2 id="settingup_autoconf">
        <title>Integration with autoconf</title>

        <para>
          Integration with <application>autoconf</application> is very simple
          and includes one required step and an additional optional
          (but recommended) step.

          The first step is to add the <function>GTK_DOC_CHECK</function> macro
          to your <filename>configure.ac</filename> script. This registers
          several configure options to enable GTK-Doc and allows you
          to set default arguments for <application>gtkdocize</application>.
        </para>

        <warning>
          <simpara>
            Make sure that the <code>GTK_DOC_CHECK</code> macro is not indented.
            The macro must start at the beginning of the line and should not
            start with whitespace.
          </simpara>
        </warning>

        <para>
          The second step is to add the <code>AC_CONFIG_MACRO_DIR(m4)</code>
          to your <filename>configure.ac</filename>. This is not required
          but helps <application>gtkdocize</application> to automatically copy
          the macro definition (e.g <filename>gtk-doc.m4</filename>) which
          contains the <function>GTK_DOC_CHECK</function> macro to your
          project's macro directory. Without this, the GTK_DOC_CHECK macro
          might not be found and you would need to explicitly tell the
          <application>aclocal</application> tool where to find the macro
          definition file.
        </para>

        <para>
          <example><title>Minimal integration with autoconf</title>
            <programlisting><![CDATA[
# recommended: set m4 directory
AC_CONFIG_MACRO_DIR(m4)
# optional: register gtk-doc in configure
GTK_DOC_CHECK([1.28])
]]></programlisting>
          </example>
        </para>

        <para>
          The above example works, but will require all developers to have
          gtk-doc installed. A better way is to make building the documentation
          optional as shown in the next example:

          <example>
            <title>Integration with optional gtk-doc dependency</title>
            <programlisting><![CDATA[
m4_ifdef([GTK_DOC_CHECK], [
# recommended: set m4 directory
AC_CONFIG_MACRO_DIR(m4)
# optional: register gtk-doc in configure
GTK_DOC_CHECK([1.28])
],[
AM_CONDITIONAL([ENABLE_GTK_DOC], false)
])
]]></programlisting>
          </example>
        </para>

        <para>
          The first argument is used to check for the Gtk-Doc version at
          configure time. The 2nd, optional argument is used by
          <application>gtkdocize</application>.
          The <symbol>GTK_DOC_CHECK</symbol> macro also adds several configure
          switches:
        </para>

        <orderedlist>
          <listitem><para>--with-html-dir=PATH : path to installed docs</para></listitem>
          <listitem><para>--enable-gtk-doc : use gtk-doc to build documentation [default=no]</para></listitem>
          <listitem><para>--enable-gtk-doc-html : build documentation in html format [default=yes]</para></listitem>
          <listitem><para>--enable-gtk-doc-pdf : build documentation in pdf format [default=no]</para></listitem>
        </orderedlist>

        <important>
          <para>
            GTK-Doc is disabled by default! Remember to pass the option
            <option>'--enable-gtk-doc'</option> to the next
            <filename>configure</filename> run. Otherwise pregenerated documentation is installed
            (which makes sense for users but not for developers).
          </para>
        </important>

        <para>
          After all changes to <filename>configure.ac</filename> are made,
          update the <filename>configure</filename> file. This can be done by
          re-running <code>autogen.sh</code>.
        </para>
      </sect2>

      <sect2 id="settingup_autogen">
        <title>Integration with autogen</title>

        <para>
          Most projects will have an <filename>autogen.sh</filename> script to
          setup the build infrastructure after the project was checked out from
          a version control system (such as git or svn). GTK-Doc comes with a
          script called <application>gtkdocize</application> which can be used
          to copy the necessary files needed by Gtk-Doc to the source directory.
        </para>

        <para>
          It should be run before autoreconf, autoheader, automake or autoconf.
        </para>

        <para>
          <example><title>Running gtkdocize from autogen.sh</title>
            <programlisting><![CDATA[
gtkdocize || exit 1
]]></programlisting>
          </example>
        </para>

        <para>
          <example>
            <title>Conditionally run gtkdocize from autogen.sh</title>
            <programlisting><![CDATA[
GTKDOCIZE=$(which gtkdocize 2>/dev/null)
if test $? -ne 0; then
  echo "No gtk-doc support found. You can't build the docs."
else
  $GTKDOCIZE || exit 1
fi
]]></programlisting>
          </example>
        </para>

        <para>
          When running <application>gtkdocize</application> it copies
          <filename>gtk-doc.make</filename> to your project root (or any
          directory specified by the <option>--docdir</option> option).
        </para>

        <para>
          <application>gtkdocize</application> checks your
          <filename>configure.ac</filename> script for
          the <function>GTK_DOC_CHECK</function> macro.
          The <function>GTK_DOC_CHECK</function> macro can be used to pass
          extra arguments to the <application>gtkdocize</application> script.
          the 2nd parameter in the <function>GTK_DOC_CHECK</function> macro.
        </para>

        <para>
          Alternatively, additional arguments can also be passed to
          <application>gtkdocize</application> via the
          <function>GTKDOCIZE_FLAGS</function> environment variable, or by
          directly specifying them to <application>gtkdocize</application>
          in <filename>autogen.sh</filename>.
        </para>

      </sect2>

      <sect2 id="settingup_firstrun">
        <title>Executing GTK-Doc from the Build System</title>

        <para>After the previous steps it is time to run the build. First we need to rerun <filename>autogen.sh</filename>. If this script runs <filename>configure</filename> for you, then give it the <option>--enable-gtk-doc</option> option. Otherwise manually run <filename>configure</filename> with this option afterwards.</para>
        <para>
          The first make run generates several additional files in the doc-directories.
          The important ones are:
          <filename>&lt;package&gt;.types</filename>,
          <filename>&lt;package&gt;-docs.xml</filename> (in the past .sgml),
          <filename>&lt;package&gt;-sections.txt</filename>.
        </para>
        <para>
          <example><title>Running the doc build</title>
            <programlisting><![CDATA[
./autogen.sh --enable-gtk-doc
make
]]></programlisting>
          </example>
        </para>

        <para>
          Now you can point your browser to
          <filename>docs/reference/&lt;package&gt;/index.html</filename>.
          With this initial setup you will only see a very simple document.
          The next chapter will teach you how to add API documentation to your
          code via special comment blocks. The Chapter afterwards introduces
          <link linkend="metafiles">additional files</link> and shows how to
          edit the <link linkend="metafiles_master">master template</link> to
          add additional chapters and sections to your documentation files.
        </para>

      </sect2>

    </sect1>

    <sect1 id="settingup_cmake">
      <title>Integration with CMake build systems</title>

      <para>
        GTK-Doc now provides a <filename>GtkDocConfig.cmake</filename> module
        (and the corresponding <filename>GtkDocConfigVersion.cmake</filename>
        module). This provides a <literal>gtk_doc_add_module</literal>
        command that you can set in your <filename>CMakeLists.txt</filename>
        file.
      </para>

      <para>
        The following example shows how to use this command.
        <example><title>Example of using GTK-Doc from CMake</title>
          <programlisting><![CDATA[
find_package(GtkDoc 1.25 REQUIRED)

# Create the doc-libmeep target.
gtk_doc_add_module(
   libmeep ${CMAKE_SOURCE_DIR}/libmeep
      XML meep-docs.xml
      LIBRARIES libmeep
)

# Build doc-libmeep as part of the default target. Without this, you would
# have to explicitly run something like `make doc-libmeep` to build the docs.
add_custom_target(documentation ALL DEPENDS doc-libmeep)

# Install the docs. (This assumes you're using the GNUInstallDirs CMake module
# to set the CMAKE_INSTALL_DOCDIR variable correctly).
install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/libmeep/html
        DESTINATION ${CMAKE_INSTALL_DOCDIR})
]]></programlisting>
        </example>
      </para>
    </sect1>

    <sect1 id="settingup_plain_makefiles">
      <title>Integration with plain makefiles or other build systems</title>

      <para>
        In the case one does not want to use automake and therefore
        <filename>gtk-doc.mak</filename> one will need to call the gtkdoc tools
        in the right order in own makefiles (or other build tools).
      </para>

      <para>
        <example><title>Documentation build steps</title>
          <programlisting><![CDATA[
DOC_MODULE=meep
// sources have changed
gtkdoc-scan --module=$(DOC_MODULE) <source-dir>
gtkdoc-scangobj --module=$(DOC_MODULE)
gtkdoc-mkdb --module=$(DOC_MODULE) --output-format=xml --source-dir=<source-dir>
// xml files have changed
mkdir html
cd html && gtkdoc-mkhtml $(DOC_MODULE) ../meep-docs.xml
gtkdoc-fixxref --module=$(DOC_MODULE) --module-dir=html
]]></programlisting>
        </example>
      </para>

      <para>
        One will need to look at the <filename>Makefile.am</filename> and
        <filename>gtk-doc.mak</filename> to pick the extra options needed.
      </para>
    </sect1>

    <sect1 id="settingup_vcs">
      <title>Integration with version control systems</title>

      <para>
        As a rule of thumb, it's the files you edit which should go under
        version control. For typical projects it's these files:
        <filename>&lt;package&gt;.types</filename>,
        <filename>&lt;package&gt;-docs.xml</filename> (in the past .sgml),
        <filename>&lt;package&gt;-sections.txt</filename>,
        <filename>Makefile.am</filename>.
      </para>
      <para>
        Files in the <filename>xml/</filename> and <filename>html/</filename>
        directories should not go under version control. Neither should any of
        the <filename>.stamp</filename> files.
      </para>
    </sect1>

  </chapter>

  <chapter id="documenting">
    <title>Documenting the code</title>

    <para>
      GTK-Doc uses source code comment with a special syntax for code documentation.
      Further it retrieves information about your project structure from other
      sources. During the next section you will find all information about the
      syntax of the comments.
    </para>

    <para>
      The GTK-Doc scanner can handle the majority of C headers fine. In the
      case of receiving warnings from the scanner that look like a special
      case, one can hint GTK-Doc to skip over them.
      <example><title>GTK-Doc comment block</title>
        <programlisting><![CDATA[
#ifndef __GTK_DOC_IGNORE__
/* unparseable code here */
#endif
]]></programlisting>
      </example>
    </para>

    <note>
      <title>Limitations</title>
      <para>
        Note, that GTK-Doc's supports
        <code>#ifndef(__GTK_DOC_IGNORE__)</code> but not
        <code>#if !defined(__GTK_DOC_IGNORE__)</code> or other combinations.
      </para>
    </note>

    <!--  -->

    <sect1 id="documenting_syntax">
      <title>Documentation comments</title>

      <para>
        A multiline comment that starts with an additional '*' marks a
        documentation block that will be processed by the GTK-Doc tools.
        <example><title>GTK-Doc comment block</title>
          <programlisting><![CDATA[
/**
 * identifier:
 * documentation ...
 */
]]></programlisting>
        </example>
      </para>

      <para>The 'identifier' is one line with the name of the item to which the comment is related. The syntax differs a little depending on the item. (TODO add table showing identifiers)</para>

      <para>
        The 'documentation' block is also different for each symbol type. Symbol
        types that get parameters such as functions or macros have the parameter
        description first followed by a blank line (just a '*').
        Afterwards follows the detailed description. All lines (outside program
        listings and CDATA sections) just containing a ' *' (blank-asterisk) are
        converted to paragraph breaks.
        If you don't want a paragraph break, change that into ' *  '
        (blank-asterisk-blank-blank). This is useful in preformatted text (code
        listings).
      </para>

      <tip>
        <para>
          When documenting code, describe two aspects:
          <itemizedlist>
             <listitem>
               <para>
                 What it is: The name for a class or function can sometimes
                 be misleading for people coming from a different background.
                </para>
             </listitem>
             <listitem>
               <para>
                 What it does: Tell about common uses. Put it in relation
                 with the other API.
               </para>
             </listitem>
           </itemizedlist>
        </para>
      </tip>

      <para>
        One advantage of hyper-text over plain-text is the ability to have links
        in the document. Writing the correct markup for a link can be tedious
        though. GTK-Doc comes to help by providing several useful abbreviations.
        <itemizedlist>
          <listitem>
            <para>
              Use function() to refer to functions or macros which take arguments.
            </para>
          </listitem>
          <listitem>
            <para>
              Use @param to refer to parameters. Also use this when referring to
              parameters of other functions, related to the one being described.
            </para>
          </listitem>
          <listitem>
            <para>
              Use %constant to refer to a constant, e.g. %G_TRAVERSE_LEAFS.
            </para>
          </listitem>
          <listitem>
            <para>
              Use #symbol to refer to other types of symbol, e.g. structs and
              enums and macros which don't take arguments.
            </para>
          </listitem>
          <listitem>
            <para>
              Use #Object::signal to refer to a GObject signal.
            </para>
          </listitem>
          <listitem>
            <para>
              Use #Object:property to refer to a GObject property.
            </para>
          </listitem>
          <listitem>
            <para>
              Use #Struct.field to refer to a field inside a structure and
              #GObjectClass.foo_bar() to refer to a vmethod.
            </para>
          </listitem>
        </itemizedlist>
      </para>

      <tip>
        <para>
          If you need to use the special characters '&lt;', '&gt;', '()', '@',
          '%', or '#' in your documentation without GTK-Doc changing them you
          can use the XML entities "&amp;lt;", "&amp;gt;", "&amp;lpar;",
          "&amp;rpar;", "&amp;commat;", "&amp;percnt;" and "&amp;num;"
          respectively or escape them with a backslash '\'.
        </para>
      </tip>

      <para>
        DocBook can do more than just links. One can also have lists,
        examples, headings, and images. As of version 1.20, the
        preferred way is to use a subset of the basic text formatting
        syntax called
        <ulink url="http://daringfireball.net/projects/markdown/">Markdown</ulink>.
        On older GTK-Doc versions any documentation that includes
        Markdown will be rendered as is.  For example, list items will
        appear as lines starting with a dash.
      </para>

      <para>
        While markdown is now preferred one can mix both. One limitation here is
        that one can use docbook xml within markdown, but markdown within
        docbook xml is not supported.
      </para>

      <para>
        In older GTK-Doc releases, if you need support for additional
        formatting, you would need to enable the usage of docbook
        XML tags inside doc-comments by putting <option>--xml-mode</option>
        (or <option>--sgml-mode</option>) in the variable
        <symbol>MKDB_OPTIONS</symbol> inside <filename>Makefile.am</filename>.
      </para>

      <para>
        <example><title>GTK-Doc comment block using Markdown</title>
          <programlisting><![CDATA[
/**
 * identifier:
 *
 * documentation paragraph ...
 *
 * # Sub Heading #
 *
 * ## Second Sub Heading
 *
 * # Sub Heading With a Link Anchor # {#heading-two}
 *
 * more documentation:
 *
 * - list item 1
 *
 *   Paragraph inside a list item.
 *
 * - list item 2
 *
 * 1. numbered list item
 *
 * 2. another numbered list item
 *
 * Another paragraph. [A Link to the GNOME Website](http://www.gnome.org/)
 *
 * ![an inline image](plot-result.png)
 *
 * [A link to the heading anchor above][heading-two]
 *
 * A C-language example:
 * |[<!-- language="C" -->
 * GtkWidget *label = gtk_label_new ("Gorgeous!");
 * ]|
 */
]]></programlisting>
        </example>
      </para>

      <para>
        More examples of what markdown tags are supported can be found in the
        <ulink url="https://wiki.gnome.org/Projects/GTK%2B/DocumentationSyntax/Markdown">GTK+ Documentation Markdown Syntax Reference</ulink>.
      </para>

      <tip>
        <para>
          As already mentioned earlier GTK-Doc is for documenting public API. Thus
          one cannot write documentation for static symbols. Nevertheless it is good
          to comment those symbols too. This helps other developers to understand
          your code.
          Therefore we recommend to comment these using normal comments (without the
          2nd '*' in the first line).
          If later the function needs to be made public, all one needs to do is to
          add another '*' in the comment block and insert the symbol name at the
          right place inside the sections file.
        </para>
      </tip>
    </sect1>

    <sect1 id="documenting_sections">
      <title>Documenting sections</title>

      <para>
        Each section of the documentation contains information about one class
        or module. To introduce the component one can write a section block.
        The short description is also used inside the table of contents.
        All the @fields are optional.
      </para>

      <para>
        <example><title>Section comment block</title>
          <programlisting><![CDATA[
/**
 * SECTION:meepapp
 * @short_description: the application class
 * @title: Meep application
 * @section_id:
 * @see_also: #MeepSettings
 * @stability: Stable
 * @include: meep/app.h
 * @image: application.png
 *
 * The application class handles ...
 */
]]></programlisting>
        </example>
      </para>

      <variablelist>
        <varlistentry>
          <term>SECTION:&lt;name&gt;</term>
          <listitem>
            <para>
              The name links the section documentation to the respective part in
              the <filename>&lt;package&gt;-sections.txt</filename> file. The
              name given here should match the &lt;FILE&gt; tag in the
              <filename>&lt;package&gt;-sections.txt</filename> file.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>@short_description</term>
          <listitem>
            <para>A one line description of the section that later will appear after the links in the TOC and at the top of the section page.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>@title</term>
          <listitem>
            <para>
              The section title defaults to &lt;name&gt; from the SECTION
              declaration. It can be overridden with the @title field.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>@section_id</term>
          <listitem>
            <para>
              Overrides the use of title as a section identifier. For GObjects
              the &lt;title&gt; is used as a section_id and for other sections
              it is &lt;MODULE&gt;-&lt;title&gt;.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>@see_also</term>
          <listitem>
            <para>
              A list of symbols that are related to this section.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>@stability</term>
          <listitem>
            <para>
              An informal description of the stability level this API has.
              We recommend the use of one of these terms:
              <itemizedlist>
                <listitem>
                  <para>
                    Stable
                    - The intention of a Stable interface is to enable arbitrary
                    third parties to develop applications to these interfaces,
                    release them, and have confidence that they will run on all
                    minor releases of the product (after the one in which the
                    interface was introduced, and within the same major release).
                    Even at a major release, incompatible changes are expected
                    to be rare, and to have strong justifications.
                  </para>
                </listitem>
                <listitem>
                  <para>
                    Unstable
                    - Unstable interfaces are experimental or transitional.
                    They are typically used to give outside developers early
                    access to new or rapidly changing technology, or to provide
                    an interim solution to a problem where a more general
                    solution is anticipated.
                    No claims are made about either source or binary
                    compatibility from one minor release to the next.
                  </para>
                </listitem>
                <listitem>
                  <para>
                    Private
                    - An interface that can be used within the GNOME stack
                    itself, but that is not documented for end-users. Such
                    functions should only be used in specified and documented
                    ways.
                  </para>
                </listitem>
                <listitem>
                  <para>
                    Internal
                    - An interface that is internal to a module and does not
                    require end-user documentation. Functions that are
                    undocumented are assumed to be Internal.
                  </para>
                </listitem>
              </itemizedlist>
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>@include</term>
          <listitem>
            <para>The <literal>#include</literal> files to show in the section synopsis (a comma-separated list), overriding the global value from the <link linkend="metafiles_sections">section file</link> or command line. This item is optional.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>@image</term>
          <listitem>
            <para>
              The image to display at the top of the reference page for this
              section.  This will often be some sort of a diagram to illustrate
              the visual appearance of a class or a diagram of its relationship
              to other classes.  This item is optional.
            </para>
          </listitem>
        </varlistentry>
      </variablelist>

      <tip>
        <para>To avoid unnecessary recompilation after doc-changes put the section docs into the C source where possible.</para>
      </tip>

    </sect1>

    <sect1 id="documenting_symbols">
      <title>Documenting symbols</title>

      <para>
        Each symbol (function, macro, struct, enum, signal and property) is
        documented in a separate block. The block is best placed close to the
        definition of the symbols so that it is easy to keep them in sync.
        Thus functions are usually documented in the c-source and macros,
        structs and enums in the header file.
      </para>

      <sect2><title>General tags</title>

        <para>
          You can add versioning information to all documentation elements to tell
          when an API was introduced, or when it was deprecated.
        </para>

        <variablelist><title>Versioning Tags</title>
          <varlistentry><term>Since:</term>
            <listitem>
              <para>Description since which version of the code the API is available.</para>
            </listitem>
          </varlistentry>
          <varlistentry><term>Deprecated:</term>
            <listitem>
              <para>Paragraph denoting that this function should no be used any more. The description should point the reader to the new API.</para>
            </listitem>
          </varlistentry>
        </variablelist>

        <para>
          You can also add stability information to all documentation elements
          to indicate whether API stability is guaranteed for them for all
          future minor releases of the project.
        </para>

        <para>
          The default stability level for all documentation elements can be set
          by passing the <option>--default-stability</option> argument to
          <application>gtkdoc-mkdb</application> with one of the values below.
        </para>

        <variablelist><title>Stability Tags</title>
          <varlistentry><term>Stability: Stable</term>
            <listitem>
              <para>
                Mark the element as stable. This is for public APIs which are
                guaranteed to remain stable for all future minor releases of the
                project.
              </para>
            </listitem>
          </varlistentry>
          <varlistentry><term>Stability: Unstable</term>
            <listitem>
              <para>
                Mark the element as unstable. This is for public APIs which are
                released as a preview before being stabilised.
              </para>
            </listitem>
          </varlistentry>
          <varlistentry><term>Stability: Private</term>
            <listitem>
              <para>
                Mark the element as private. This is for interfaces which can be
                used by tightly coupled modules, but not by arbitrary third
                parties.
              </para>
            </listitem>
          </varlistentry>
        </variablelist>

        <example><title>General tags</title>
          <programlisting><![CDATA[
/**
 * foo_get_bar:
 * @foo: some foo
 *
 * Retrieves @foo's bar.
 *
 * Returns: @foo's bar
 *
 * Since: 2.6
 * Deprecated: 2.12: Use foo_baz_get_bar() instead.
 */
Bar *
foo_get_bar(Foo *foo)
{
...
]]></programlisting>
        </example>
      </sect2>

      <sect2><title>Annotations</title>

        <para>
          Documentation blocks can contain annotation-tags. These tags will be
          rendered with tooltips describing their meaning. The tags are used by
          gobject-introspection to generate language bindings. A detailed list
          of the supported tags can be found on
          <ulink url="http://live.gnome.org/GObjectIntrospection/Annotations" type="http">the wiki</ulink>.
        </para>

        <example><title>Annotations</title>
          <programlisting><![CDATA[
/**
 * foo_get_bar: (annotation)
 * @foo: (annotation): some foo
 *
 * Retrieves @foo's bar.
 *
 * Returns: (annotation): @foo's bar
 */
...
/**
 * foo_set_bar_using_the_frobnicator: (annotation) (another annotation)
 *                                    (and another annotation)
 * @foo: (annotation) (another annotation): some foo
 *
 * Sets bar on @foo.
 */
]]></programlisting>
        </example>
      </sect2>

      <sect2><title>Function comment block</title>

        <para>
          Please remember to:
          <itemizedlist>
            <listitem>
              <para>
                Document whether returned objects, lists, strings, etc, should be
                freed/unrefed/released.
              </para>
            </listitem>
            <listitem>
              <para>
                Document whether parameters can be NULL, and what happens if they are.
              </para>
            </listitem>
            <listitem>
              <para>
                Mention interesting pre-conditions and post-conditions where appropriate.
              </para>
            </listitem>
          </itemizedlist>
        </para>

        <para>GTK-Doc assumes all symbols (macros, functions) starting with <literal>_</literal> are private. They are treated like static functions.</para>

        <example><title>Function comment block</title>
          <programlisting><![CDATA[
/**
 * function_name:
 * @par1:  description of parameter 1. These can extend over more than
 * one line.
 * @par2:  description of parameter 2
 * @...: a %NULL-terminated list of bars
 *
 * The function description goes here. You can use @par1 to refer to parameters
 * so that they are highlighted in the output. You can also use %constant
 * for constants, function_name2() for functions and #GtkWidget for links to
 * other declarations (which may be documented elsewhere).
 *
 * Returns: an integer.
 *
 * Since: 2.2
 * Deprecated: 2.18: Use other_function() instead.
 */
]]></programlisting>
        </example>

        <variablelist><title>Function tags</title>
          <varlistentry><term>Returns:</term>
            <listitem>
              <para>Paragraph describing the returned result.</para>
            </listitem>
          </varlistentry>
          <varlistentry><term>@...:</term>
            <listitem>
              <para>
                In case the function has variadic arguments, you should use this
                tag (@Varargs: does also work for historic reasons).
              </para>
            </listitem>
          </varlistentry>
        </variablelist>

      </sect2>

      <sect2><title>Property comment block</title>

        <example><title>Property comment block</title>
          <programlisting><![CDATA[
/**
 * SomeWidget:some-property:
 *
 * Here you can document a property.
 */
g_object_class_install_property (object_class, PROP_SOME_PROPERTY, ...);
]]></programlisting>
        </example>

      </sect2>

      <sect2><title>Signal comment block</title>

        <para>
          Please remember to:
          <itemizedlist>
            <listitem>
              <para>
                Document when the signal is emitted and whether it is emitted before
                or after other signals.
              </para>
            </listitem>
            <listitem>
              <para>
                Document what an application might do in the signal handler.
              </para>
            </listitem>
          </itemizedlist>
        </para>

        <example><title>Signal comment block</title>
          <programlisting><![CDATA[
/**
 * FooWidget::foobarized:
 * @widget: the widget that received the signal
 * @foo: some foo
 * @bar: some bar
 *
 * The ::foobarized signal is emitted each time someone tries to foobarize @widget.
 */
foo_signals[FOOBARIZED] =
  g_signal_new ("foobarized",
                ...
]]></programlisting>
        </example>

      </sect2>

      <sect2><title>Struct comment block</title>
        <example><title>Struct comment block</title>
          <programlisting><![CDATA[
/**
 * FooWidget:
 * @bar: some #gboolean
 *
 * This is the best widget, ever.
 */
typedef struct _FooWidget {
  GtkWidget parent_instance;

  gboolean bar;
} FooWidget;
]]></programlisting>
        </example>

        <para>
          Use <code>/*&lt; private &gt;*/</code> before the private struct fields
          you want to hide. Use <code>/*&lt; public &gt;*/</code> for the reverse
          behaviour.
        </para>

        <para>
          If the first field is "g_iface", "parent_instance" or "parent_class"
          it will be considered private automatically and doesn't need to be
          mentioned in the comment block.
        </para>

        <para>
          Struct comment blocks can also be used for GObjects and GObjectClasses.
          It is usually a good idea to add a comment block for a class, if it has
          vmethods (as this is how they can be documented). For the GObject
          itself one can use the related section docs, having a separate block
          for the instance struct would be useful if the instance has public
          fields. One disadvantage here is that this creates two index entries
          of the same name (the structure and the section).
        </para>

      </sect2>

      <sect2><title>Enum comment block</title>
        <example><title>Enum comment block</title>
          <programlisting><![CDATA[
/**
 * Something:
 * @SOMETHING_FOO: something foo
 * @SOMETHING_BAR: something bar
 *
 * Enum values used for the thing, to specify the thing.
 */
typedef enum {
  SOMETHING_FOO,
  SOMETHING_BAR,
  /*< private >*/
  SOMETHING_COUNT
} Something;
]]></programlisting>
        </example>

        <para>
          Use <code>/*&lt; private &gt;*/</code> before the private enum values
          you want to hide. Use <code>/*&lt; public &gt;*/</code> for the reverse
          behaviour.
        </para>

      </sect2>
    </sect1>


    <sect1 id="documenting_inline_program">
      <title>Inline program documentation</title>
      <para>
         You can document programs and their commandline interface using inline
         documentation.
      </para>

      <variablelist>
      <title>Tags</title>

      <varlistentry><term>PROGRAM</term>

      <listitem>
      <para>
         Defines the start of a program documentation.
      </para>
      </listitem>
      </varlistentry>

      <varlistentry>
      <term>@short_description:</term>
      <listitem>
      <para>
         Defines a short description of the program. (Optional)
      </para>
      </listitem>
      </varlistentry>

      <varlistentry>
      <term>@synopsis:</term>
      <listitem>
      <para>
         Defines the arguments, or list of arguments that the program can take.
         (Optional)
      </para>
      </listitem>
      </varlistentry>

      <varlistentry>
      <term>@see_also:</term>
      <listitem>
      <para>
          See Also manual page section. (Optional)
      </para>
      </listitem>
      </varlistentry>

      <varlistentry>
      <term>@arg:</term>
      <listitem>
      <para>
          Argument(s) passed to the program and their description. (Optional)
      </para>
      </listitem>
      </varlistentry>

      <varlistentry>
      <term>Description:</term>
      <listitem>
      <para>
          A longer description of the program.
      </para>
      </listitem>
      </varlistentry>

      <varlistentry>
      <term>Returns:</term>
      <listitem>
      <para>
          Specify what value(s) the program returns. (Optional)
      </para>
      </listitem>
      </varlistentry>

      </variablelist>

      <sect2>
        <title>Example of program documentation.</title>
        <example><title>Program documentation block</title>
        <programlisting><![CDATA[
/**
 * PROGRAM:test-program
 * @short_description: A test program
 * @synopsis: test-program [*OPTIONS*...] --arg1 *arg* *FILE*
 * @see_also: test(1)
 * @--arg1 *arg*: set arg1 to *arg*
 * @--arg2 *arg*: set arg2 to *arg*
 * @-v, --version: Print the version number
 * @-h, --help: Print the help message
 *
 * Long description of program.
 *
 * Returns: Zero on success, non-zero on failure
 */
int main(int argc, char *argv[])
{
	return 0;
}
]]></programlisting>
        </example>

      </sect2>
    </sect1>

    <sect1 id="documenting_docbook">
      <title>Useful DocBook tags</title>

      <para>Here are some DocBook tags which are most useful when documenting the code.</para>

      <para>
        To link to another section in the GTK docs:

        <informalexample>
          <programlisting><![CDATA[
<link linkend="glib-Hash-Tables">Hash Tables</link>
]]></programlisting>
        </informalexample>
        The linkend is the SGML/XML id on the top item of the page you want to link to.
        For most pages this is currently the part ("gtk", "gdk", "glib") and then
        the page title ("Hash Tables"). For widgets it is just the class name.
        Spaces and underscores are converted to '-' to conform to SGML/XML.
      </para>

      <para>
        To refer to an external function, e.g. a standard C function:
        <informalexample>
          <programlisting><![CDATA[
<function>...</function>
]]></programlisting>
        </informalexample>
      </para>

      <para>
        To include example code:
        <informalexample>
          <programlisting><![CDATA[
<example>
  <title>Using a GHashTable.</title>
  <programlisting language="C">
      ...
  </programlisting>
</example>
]]></programlisting>
        </informalexample>
        or possibly this, for very short code fragments which don't need a title:
        <informalexample>
          <programlisting><![CDATA[
<informalexample>
  <programlisting language="C">
  ...
  </programlisting>
</informalexample>
]]></programlisting>
        </informalexample>
        In both cases, the language attribute is optional and is used as a hint
        to the syntax highlighting engine (pygments for html output).
        For the latter GTK-Doc also supports an abbreviation:
        <informalexample>
          <programlisting><![CDATA[
|[<!-- language="C" -->
  ...
]|
]]></programlisting>
        </informalexample>
      </para>

      <para>
        To include bulleted lists:
        <informalexample>
          <programlisting><![CDATA[
<itemizedlist>
  <listitem>
    <para>
      ...
    </para>
  </listitem>
  <listitem>
    <para>
      ...
    </para>
  </listitem>
</itemizedlist>
]]></programlisting>
        </informalexample>
      </para>

      <para>
        To include a note which stands out from the text:
        <informalexample>
          <programlisting><![CDATA[
<note>
  <para>
    Make sure you free the data after use.
  </para>
</note>
]]></programlisting>
        </informalexample>
      </para>

      <para>
        To refer to a type:
        <informalexample>
          <programlisting><![CDATA[
<type>unsigned char</type>
]]></programlisting>
        </informalexample>
      </para>

      <para>
        To refer to an external structure (not one described in the GTK docs):
        <informalexample>
          <programlisting><![CDATA[
<structname>XFontStruct</structname>
]]></programlisting>
        </informalexample>
      </para>

      <para>
        To refer to a field of a structure:
        <informalexample>
          <programlisting><![CDATA[
<structfield>len</structfield>
]]></programlisting>
        </informalexample>
      </para>

      <para>
        To refer to a class name, we could possibly use:
        <informalexample>
          <programlisting><![CDATA[
<classname>GtkWidget</classname>
]]></programlisting>
        </informalexample>
        but you'll probably be using #GtkWidget instead (to automatically create
        a link to the GtkWidget page - see <link linkend="documenting_syntax">the abbreviations</link>).
      </para>

      <para>
        To emphasize text:
        <informalexample>
          <programlisting><![CDATA[
<emphasis>This is important</emphasis>
]]></programlisting>
        </informalexample>
      </para>

      <para>
        For filenames use:
        <informalexample>
          <programlisting><![CDATA[
<filename>/home/user/documents</filename>
]]></programlisting>
        </informalexample>
      </para>

      <para>
        To refer to keys use:
        <informalexample>
          <programlisting><![CDATA[
<keycombo><keycap>Control</keycap><keycap>L</keycap></keycombo>
]]></programlisting>
        </informalexample>
      </para>

    </sect1>
  </chapter>

  <chapter id="metafiles">
    <title>Filling the extra files</title>

    <para>
      There are a couple of extra files, that need to be maintained along with
      the inline source code comments:
      <filename>&lt;package&gt;.types</filename>,
      <filename>&lt;package&gt;-docs.xml</filename> (in the past .sgml),
      <filename>&lt;package&gt;-sections.txt</filename>.
    </para>

    <sect1 id="metafiles_types">
      <title>Editing the types file</title>

      <para>
        If your library or application includes GObjects, you want
        their signals, arguments/parameters and position in the hierarchy to be
        shown in the documentation. All you need to do, is to list the
        <function>xxx_get_type</function> functions together with their include
        inside the <filename>&lt;package&gt;.types</filename> file.
      </para>

      <para>
        <example><title>Example &lt;package&gt;.types file</title>
          <programlisting><![CDATA[
#include <gtk/gtk.h>

gtk_accel_label_get_type
gtk_adjustment_get_type
gtk_alignment_get_type
gtk_arrow_get_type
]]></programlisting>
        </example>
      </para>

      <para>
        Since GTK-Doc 1.8 <application>gtkdoc-scan</application> can generate this list for you.
        Just add "--rebuild-types" to SCAN_OPTIONS in <filename>Makefile.am</filename>. If you
        use this approach you should not dist the types file nor have it under version control.
      </para>

    </sect1>

    <sect1 id="metafiles_master">
      <title>Editing the master document</title>

      <para>
        GTK-Doc produces documentation in DocBook SGML/XML. When processing the
        inline source comments, the GTK-Doc tools generate one documentation
        page per class or module as a separate file. The master document
        includes them and place them in an order.
      </para>

      <para>
        While GTK-Doc creates a template master document for you, later runs will
        not touch it again. This means that one can freely structure the
        documentation. That includes grouping pages and adding extra pages.
        GTK-Doc has now a test suite, where also the master-document is recreated from scratch.
        Its a good idea to look at this from time to time to see if there are
        some new goodies introduced there.
      </para>

      <tip>
        <para>Do not create tutorials as extra documents. Just write extra chapters. The benefit of directly embedding the tutorial for your library into the API documentation is that it is easy to link for the tutorial to symbol documentation. Also, chances are higher that the tutorial gets updates along with the library.</para>
      </tip>

      <para>So what are the things to change inside the master document? There are some placeholders (text in square brackets) there which you should take care of.</para>

      <para>
        <example><title>Master document header</title>
          <programlisting><![CDATA[
<bookinfo>
  <title>MODULENAME Reference Manual</title>
  <releaseinfo>
    for MODULENAME [VERSION]
    The latest version of this documentation can be found on-line at
    <ulink role="online-location" url="http://[SERVER]/MODULENAME/index.html">http://[SERVER]/MODULENAME/</ulink>.
  </releaseinfo>
</bookinfo>

<chapter>
  <title>[Insert title here]</title>
]]></programlisting>
        </example>
      </para>

      <para>
        In addition a few option elements are created in commented form. You can
        review these and enable them as you like.
      </para>

      <para>
        <example><title>Optional part in the master document</title>
          <programlisting><![CDATA[
  <!-- enable this when you use gobject introspection annotations
  <xi:include href="xml/annotation-glossary.xml"><xi:fallback /></xi:include>
  -->
]]></programlisting>
        </example>
      </para>

      <para>
        Finally you need to add new section whenever you introduce one. The
        <link linkend="modernizing-gtk-doc-1-16">gtkdoc-check</link> tool will
        remind you of newly generated xml files that are not yet included into
        the doc.
      </para>

      <para>
        <example><title>Including generated sections</title>
          <programlisting><![CDATA[
  <chapter>
    <title>my library</title>
      <xi:include href="xml/object.xml"/>
      ...
]]></programlisting>
        </example>
      </para>

    </sect1>

    <sect1 id="metafiles_sections">
      <title>Editing the section file</title>

      <para>
        The section file is used to organise the documentation output by
        GTK-Doc. Here one specifies which symbol belongs to which module or
        class and control the visibility (public or private).
      </para>

      <para>
        The section file is a plain text file with tags delimiting sections.
        Blank lines are ignored and lines starting with a '#' are treated as
        comment lines.
      </para>

      <note>
        <para>
          While the tags make the file look like xml, it is not. Please do not
          close tags like &lt;SUBSECTION&gt;.
        </para>
      </note>

      <para>
        <example><title>Including generated sections</title>
          <programlisting><![CDATA[
<INCLUDE>libmeep/meep.h</INCLUDE>

<SECTION>
<FILE>meepapp</FILE>
<TITLE>MeepApp</TITLE>
MeepApp
<SUBSECTION Standard>
MEEP_APP
...
MeepAppClass
meep_app_get_type
</SECTION>
]]></programlisting>
        </example>
      </para>

      <para>
        The &lt;FILE&gt; ... &lt;/FILE&gt; tag is used to specify the file name,
        without any suffix. For example, using '&lt;FILE&gt;gnome-config&lt;/FILE&gt;'
        will result in the section declarations being output in the template
        file <filename>tmpl/gnome-config.sgml</filename>, which will be
        converted into the DocBook XML file <filename>xml/gnome-config.sgml</filename>
        or the DocBook XML file <filename>xml/gnome-config.xml</filename>.
        (The name of the HTML file is based on the module name and the section
        title, or for GObjects it is based on the GObjects class name converted
        to lower case).
      </para>

      <para>
        The &lt;TITLE&gt; ... &lt;/TITLE&gt; tag is used to specify the title of
        the section. It is only useful before the templates (if used) are
        initially created, since the title set in the template file overrides
        this. Also if one uses SECTION comment in the sources, this is obsolete.
      </para>

      <para>
        You can group items in the section by using the &lt;SUBSECTION&gt; tag.
        Currently it outputs a blank line between subsections in the synopsis
        section.
        You can also use &lt;SUBSECTION Standard&gt; for standard GObject
        declarations (e.g. the functions like g_object_get_type and macros like
        G_OBJECT(), G_IS_OBJECT() etc.).
        Currently these are left out of the documentation.
        You can also use &lt;SUBSECTION Private&gt; for private declarations
        which will not be output (it is a handy way to avoid warning messages
        about unused declarations).
        If your library contains private types which you don't want to appear in
        the object hierarchy and the list of implemented or required interfaces,
        add them to a Private subsection.
        Whether you would place GObject and GObjectClass like structs in public
        or Standard section depends if they have public entries (variables,
        vmethods).
      </para>

      <para>You can also use &lt;INCLUDE&gt; ... &lt;/INCLUDE&gt; to specify the <literal>#include</literal> files which are shown in the synopsis sections. It contains a comma-separated list of <literal>#include</literal> files, without the angle brackets. If you set it outside of any sections, it acts for all sections until the end of the file. If you set it within a section, it only applies to that section.</para>

    </sect1>

  </chapter>

  <chapter id="reports">
    <title>Controlling the result</title>

    <para>
      A GTK-Doc run generates report files inside the documentation directory.
      The generated files are named:
      <filename>&lt;package&gt;-undocumented.txt</filename>,
      <filename>&lt;package&gt;-undeclared.txt</filename> and
      <filename>&lt;package&gt;-unused.txt</filename>.
      All those are plain text files that can be viewed and postprocessed easily.
    </para>

    <para>The <filename><replaceable>package</replaceable>-undocumented.txt</filename> file starts with the documentation coverage summary. Below are two sections divided by blank lines. The first section lists undocumented or incomplete symbols. The second section does the same for section docs. Incomplete entries are those, which have documentation, but where e.g. a new parameter has been added.</para>

    <para>
      The <filename>&lt;package&gt;-undeclared.txt</filename> file lists symbols
      given in the <filename>&lt;package&gt;-sections.txt</filename> but not
      found in the sources. Check if they have been removed or if they are
      misspelled.
    </para>

    <para>
      The <filename>&lt;package&gt;-unused.txt</filename> file lists symbol
      names, where the GTK-Doc scanner has found documentation, but does not
      know where to put it. This means that the symbol has not yet been added to
      the <filename>&lt;package&gt;-sections.txt</filename> file.
    </para>

    <tip>
      <para>
        Enable or add the <option>TESTS=$(GTKDOC_CHECK)</option> line in Makefile.am.
        If at least GTK-Doc 1.9 is installed, this will run sanity checks during
        <command>make check</command> run.
      </para>
    </tip>

    <para>
      One can also look at the files produced by the source code scanner:
      <filename>&lt;package&gt;-decl-list.txt</filename> and
      <filename>&lt;package&gt;-decl.txt</filename>. The first one can be
      compared with the section file if that is manually maintained. The second
      lists all declarations from the headers. If a symbol is missing one could
      check if this file contains it.
    </para>

    <para>
      If the project is GObject based, one can also look into the files produced
      by the object scanner:
      <filename>&lt;package&gt;.args.txt</filename>,
      <filename>&lt;package&gt;.hierarchy.txt</filename>,
      <filename>&lt;package&gt;.interfaces.txt</filename>,
      <filename>&lt;package&gt;.prerequisites.txt</filename> and
      <filename>&lt;package&gt;.signals.txt</filename>. If there are missing
      symbols in any of those, one can ask GTK-Doc to keep the intermediate
      scanner file for further analysis, by running it as
      <command>GTK_DOC_KEEP_INTERMEDIATE=1 make</command>.
    </para>
  </chapter>

  <chapter id="modernizing">
    <title>Modernizing the documentation</title>

    <para>
      GTK-Doc has been around for quite some time. In this section we list new
      features together with the version since when it is available.
    </para>

    <sect1 id="modernizing-gtk-doc-1-9">
      <title>GTK-Doc 1.9</title>

      <para>
        When using xml instead of sgml, one can actually name the master
        document <filename>&lt;package&gt;-docs.xml</filename>.
      </para>

      <para>
        This version supports <option>SCAN_OPTIONS=--rebuild-sections</option>
        in <filename>Makefile.am</filename>. When this is enabled, the
        <filename>&lt;package&gt;-sections.txt</filename> is autogenerated and
        can be removed from the vcs. This only works nicely for projects that
        have a very regular structure (e.g. each .{c,h} pair will create new
        section). If one organize a project close to that updating a manually
        maintained section file can be as simple as running
        <code>meld &lt;package&gt;-decl-list.txt &lt;package&gt;-sections.txt</code>.
      </para>

      <para>
        Version 1.8 already introduced the syntax for documenting sections in
        the sources instead of the separate files under <filename class="directory">tmpl</filename>.
        This version adds options to switch the whole doc module to not use the
        extra tmpl build step at all, by using <option>--flavour no-tmpl</option>
        in <filename>configure.ac</filename>. If you don't have a <filename class="directory">tmpl</filename>
        checked into your source control system and haven't yet switched, just
        add the flag to <filename>configure.ac</filename> and you are done.
      </para>
    </sect1>

    <sect1 id="modernizing-gtk-doc-1-10">
      <title>GTK-Doc 1.10</title>

      <para>
        This version supports <option>SCAN_OPTIONS=--rebuild-types</option> in
        <filename>Makefile.am</filename>. When this is enabled, the
        <filename>&lt;package&gt;.types</filename> is autogenerated and can be
        removed from the vcs. When using this feature it is important to also
        setup the <varname>IGNORE_HFILES</varname> in
        <filename>Makefile.am</filename> for code that is build conditionally.
      </para>
    </sect1>

    <sect1 id="modernizing-gtk-doc-1-16">
      <title>GTK-Doc 1.16</title>

      <para>
        This version includes a new tool called gtkdoc-check. This tool can run
        a set of sanity checks on your documentation. It is enabled by adding
        these lines to the end of <filename>Makefile.am</filename>.
        <example><title>Enable gtkdoc-check</title>
          <programlisting><![CDATA[
if ENABLE_GTK_DOC
TESTS_ENVIRONMENT = \
  DOC_MODULE=$(DOC_MODULE) DOC_MAIN_SGML_FILE=$(DOC_MAIN_SGML_FILE) \
  SRCDIR=$(abs_srcdir) BUILDDIR=$(abs_builddir)
TESTS = $(GTKDOC_CHECK)
endif
]]></programlisting>
        </example>
      </para>
    </sect1>

    <sect1 id="modernizing-gtk-doc-1-20">
      <title>GTK-Doc 1.20</title>

      <para>
        Version 1.18 brought some initial markdown support. Using markdown in
        doc comments is less intrusive than writing docbook xml. This version
        improves a lot on this and add a lot more styles. The section that
        explains the <link linkend="documenting_syntax">comment syntax</link>
        has all the details.
      </para>
    </sect1>

    <sect1 id="modernizing-gtk-doc-1-25">
      <title>GTK-Doc 1.25</title>

      <para>
        The makefiles shipped with this version generate an entity file at <filename>xml/gtkdocentities.ent</filename>,
        containing entities for e.g. package_name and package_version. You can
        use this e.g. in the main xml file to avoid hardcoding the version
        number. Below is an example that shows how the entity file is included
        in the master template and how the entities are used.
        The entities can also be used in all
        generated files, GTK-Doc will use the same xml header in generated xml
        files.
        <example><title>Use pre-generated entities</title>
          <programlisting><![CDATA[
<?xml version="1.0"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
               "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd"
[
  <!ENTITY % local.common.attrib "xmlns:xi  CDATA  #FIXED 'http://www.w3.org/2003/XInclude'">
  <!ENTITY % gtkdocentities SYSTEM "xml/gtkdocentities.ent">
  %gtkdocentities;
]>
<book id="index" xmlns:xi="http://www.w3.org/2003/XInclude">
  <bookinfo>
    <title>&package_name; Reference Manual</title>
    <releaseinfo>
      for &package_string;.
      The latest version of this documentation can be found on-line at
      <ulink role="online-location" url="http://[SERVER]/&package_name;/index.html">http://[SERVER]/&package_name;/</ulink>.
    </releaseinfo>
  </bookinfo>
]]></programlisting>
        </example>
      </para>
    </sect1>
  </chapter>

  <chapter id="documenting-others">
    <title>Documenting other interfaces</title>

    <para>
      So far we have been using GTK-Doc to document the API of code. The next
      sections contain suggestions how the tools can be used to document other
      interfaces too.
    </para>

    <sect1 id="commandline-interfaces">
      <title>Command line options and man pages</title>

      <para>
        As one can generate man pages for a docbook refentry as well, it sounds
        like a good idea to use it for that purpose. This way the interface is
        part of the reference and one gets the man-page for free.
      </para>

      <sect2 id="commandline-interfaces-file">
        <title>Document the tool</title>

        <para>
          Create one refentry file per tool. Following
          <link linkend="settingup_docfiles">our example</link> we would call it
          <filename>meep/docs/reference/meeper/meep.xml</filename>. For the xml
          tags that should be used and can look at generated file in the xml
          subdirectory as well as examples e.g. in glib.
        </para>
      </sect2>

      <sect2 id="commandline-interfaces-configure">
        <title>Adding the extra configure check</title>

        <para>
          <example><title>Extra configure checks</title>
            <programlisting><![CDATA[
AC_ARG_ENABLE(man,
              [AC_HELP_STRING([--enable-man],
                              [regenerate man pages from Docbook [default=no]])],enable_man=yes,
              enable_man=no)

AC_PATH_PROG([XSLTPROC], [xsltproc])
AM_CONDITIONAL(ENABLE_MAN, test x$enable_man != xno)
]]></programlisting>
          </example>
        </para>
      </sect2>

      <sect2 id="commandline-interfaces-make">
        <title>Adding the extra makefile rules</title>

        <para>
          <example><title>Extra configure checks</title>
            <programlisting><![CDATA[
man_MANS = \
       meeper.1

if ENABLE_GTK_DOC
if ENABLE_MAN

%.1 : %.xml
        @XSLTPROC@ -nonet http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl $<

endif
endif

BUILT_EXTRA_DIST = $(man_MANS)
EXTRA_DIST += meep.xml
]]></programlisting>
          </example>
        </para>
      </sect2>
    </sect1>

    <sect1 id="dbus-interfaces">
      <title>DBus interfaces</title>

      <para>
        (FIXME: http://hal.freedesktop.org/docs/DeviceKit/DeviceKit.html,
http://cgit.freedesktop.org/DeviceKit/DeviceKit/tree/doc/dbus)
      </para>
    </sect1>

  </chapter>

  <chapter id="faq">
    <title>Frequently asked questions</title>

    <segmentedlist>
      <?dbhtml list-presentation="list"?>
      <segtitle>Question</segtitle>
      <segtitle>Answer</segtitle>
      <seglistitem>
        <seg>No class hierarchy.</seg>
        <seg>
          The objects <function>xxx_get_type()</function> function has not been
          entered into the <filename>&lt;package&gt;.types</filename> file.
        </seg>
      </seglistitem>
      <seglistitem>
        <seg>Still no class hierarchy.</seg>
        <seg>
          Missing or wrong naming in <filename>&lt;package&gt;-sections.txt</filename>
          file (see <ulink url="http://mail.gnome.org/archives/gtk-doc-list/2003-October/msg00006.html">explanation</ulink>).
        </seg>
      </seglistitem>
      <seglistitem>
        <seg>Damn, I still have no class hierarchy.</seg>
        <seg>
          Is the object name (name of the instance struct, e.g. <type>GtkWidget</type>)
          part of the normal section (don't put this into Standard or Private
          subsections).
        </seg>
      </seglistitem>
      <seglistitem>
        <seg>No symbol index.</seg>
        <seg>
          Does the <filename>&lt;package&gt;-docs.{xml,sgml}</filename> contain a
          index that xi:includes the generated index?
        </seg>
      </seglistitem>
      <seglistitem>
        <seg>Symbols are not linked to their doc-section.</seg>
        <seg>
          Is the doc-comment using the correct markup (added #,% or ())?
          Check if the gtkdoc-fixxref warns about unresolvable xrefs.
        </seg>
      </seglistitem>
      <seglistitem>
        <seg>A new class does not appear in the docs.</seg>
        <seg>
          Is the new page xi:included from
          <filename>&lt;package&gt;-docs.{xml,sgml}</filename>.
        </seg>
      </seglistitem>
      <seglistitem>
        <seg>A new symbol does not appear in the docs.</seg>
        <seg>
          Is the doc-comment properly formatted. Check for spelling mistakes in
          the begin of the comment. Check if the gtkdoc-fixxref warns about
          unresolvable xrefs. Check if the symbol is correctly listed in the
          <filename>&lt;package&gt;-sections.txt</filename> in a public subsection.
        </seg>
      </seglistitem>
      <seglistitem>
        <seg>A type is missing from the class hierarchy.</seg>
        <seg>
          If the type is listed in <filename>&lt;package&gt;.hierarchy</filename>
          but not in <filename>xml/tree_index.sgml</filename> then double check
          that the type is correctly placed in the <filename>&lt;package&gt;-sections.txt</filename>.
          If the type instance (e.g. <type>GtkWidget</type>) is not listed or
          incidentally marked private it will not be shown.
        </seg>
      </seglistitem>
      <seglistitem>
        <seg>I get foldoc links for all gobject annotations.</seg>
        <seg>
          Check that <filename>xml/annotation-glossary.xml</filename> is
          xi:included from <filename>&lt;package&gt;-docs.{xml,sgml}</filename>.
        </seg>
      </seglistitem>

      <!-- gtk-doc warnings: -->
      <seglistitem>
        <seg>Parameter described in source code comment block but does not exist</seg>
        <seg>Check if the prototype in the header has different parameter names to the source.</seg>
      </seglistitem>

      <!-- docbook warnings: -->
      <seglistitem>
        <seg>multiple "IDs" for constraint linkend: XYZ</seg>
        <seg>Symbol XYZ appears twice in <filename>&lt;package&gt;-sections.txt</filename> file.</seg>
      </seglistitem>
      <seglistitem>
        <seg>Element typename in namespace '' encountered in para, but no template matches.</seg>
        <seg/>
      </seglistitem>
    </segmentedlist>
  </chapter>

  <chapter id="contrib">
    <title>Tools related to gtk-doc</title>

    <para>
      GtkDocPlugin - a <ulink url="http://trac-hacks.org/wiki/GtkDocPlugin">Trac GTK-Doc</ulink>
      integration plugin, that adds API docs to a trac site and integrates with
      the trac search.
    </para>
    <para>
      Gtkdoc-depscan - a tool (part of gtk-doc) to check used API against since
      tags in the API to determine the minimum required version.
    </para>

  </chapter>

  <!-- ======== Appendix: FDL ================================== -->
  <!--  
     The GNU Free Documentation License 1.1 in DocBook
     Markup by Eric Baudais <baudais@okstate.edu>
     Maintained by the GNOME Documentation Project
     http://developer.gnome.org/projects/gdp
     Version: 1.0.1
     Last Modified: Nov 16, 2000
-->

<appendix id="fdl">
  <appendixinfo>
    <releaseinfo>Version 1.1, March 2000</releaseinfo>
    <copyright>
      <year>2000</year><holder>Free Software Foundation, Inc.</holder>
    </copyright>
    <legalnotice id="fdl-legalnotice">
      <para>
	<address>Free Software Foundation, Inc. <street>51 Franklin Street, 
        Suite 330</street>, <city>Boston</city>, <state>MA</state>  
        <postcode>02110-1301</postcode>  <country>USA</country></address> 
	Everyone is permitted to copy and distribute verbatim copies of this 
        license document, but changing it is not allowed.
      </para>
    </legalnotice>
  </appendixinfo>
  <title>GNU Free Documentation Licence</title>

  <sect1 id="fdl-preamble">
    <title>0. PREAMBLE</title>
    <para>The purpose of this Licence is to make a manual, textbook, or other written document <quote>free</quote> in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this Licence preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.</para>
    
    <para>This Licence is a kind of <quote>copyleft</quote>, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public Licence, which is a copyleft licence designed for free software.</para>
    
    <para>We have designed this Licence in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this Licence is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this Licence principally for works whose purpose is instruction or reference.</para>
  </sect1>
  <sect1 id="fdl-section1">
    <title>1. APPLICABILITY AND DEFINITIONS</title>
    <para id="fdl-document">This Licence applies to any manual or other work that contains a notice placed by the copyright holder saying it can be distributed under the terms of this Licence. The <quote>Document</quote>, below, refers to any such manual or work. Any member of the public is a licencee, and is addressed as <quote>you</quote>.</para>
    
    <para id="fdl-modified">A <quote>Modified Version</quote> of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.</para>
	
    <para id="fdl-secondary">A <quote>Secondary Section</quote> is a named appendix or a front-matter section of the <link linkend="fdl-document">Document</link> that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (For example, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.</para>

    <para id="fdl-invariant">The <quote>Invariant Sections</quote> are certain <link linkend="fdl-secondary"> Secondary Sections</link> whose titles are designated, as being those of Invariant Sections, in the notice that says that the <link linkend="fdl-document">Document</link> is released under this Licence.</para>
    
    <para id="fdl-cover-texts">The <quote>Cover Texts</quote> are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the <link linkend="fdl-document">Document</link> is released under this Licence.</para>
	
    <para id="fdl-transparent">A <quote>Transparent</quote> copy of the <link linkend="fdl-document"> Document</link> means a machine-readable copy, represented in a format whose specification is available to the general public, whose contents can be viewed and edited directly and straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup has been designed to thwart or discourage subsequent modification by readers is not Transparent. A copy that is not <quote>Transparent</quote> is called <quote>Opaque</quote>.</para>
    
    <para>Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML designed for human modification. Opaque formats include PostScript, PDF, proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML produced by some word processors for output purposes only.</para>
    
    <para id="fdl-title-page">The <quote>Title Page</quote> means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this Licence requires to appear in the title page. For works in formats which do not have any title page as such, <quote>Title Page</quote> means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text.</para>
  </sect1>
    
  <sect1 id="fdl-section2">
    <title>2. VERBATIM COPYING</title>
    <para>You may copy and distribute the <link linkend="fdl-document">Document</link> in any medium, either commercially or noncommercially, provided that this Licence, the copyright notices, and the licence notice saying this Licence applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this Licence. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in <link linkend="fdl-section3">section 3</link>.</para>
    
    <para>You may also lend copies, under the same conditions stated above, and you may publicly display copies.</para>
    </sect1>
    
  <sect1 id="fdl-section3">
    <title>3. COPYING IN QUANTITY</title>
    <para>If you publish printed copies of the <link linkend="fdl-document">Document</link> numbering more than 100, and the Document's licence notice requires <link linkend="fdl-cover-texts">Cover Texts</link>, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the <link linkend="fdl-document">Document</link> and satisfy these conditions, can be treated as verbatim copying in other respects.</para>
    
    <para>If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.</para>
    
    <para>If you publish or distribute <link linkend="fdl-transparent">Opaque</link> copies of the <link linkend="fdl-document">Document</link> numbering more than 100, you must either include a machine-readable <link linkend="fdl-transparent">Transparent</link> copy along with each Opaque copy, or state in or with each Opaque copy a publicly-accessible computer-network location containing a complete Transparent copy of the Document, free of added material, which the general network-using public has access to download anonymously at no charge using public-standard network protocols. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.</para>
    
    <para>It is requested, but not required, that you contact the authors of the <link linkend="fdl-document">Document</link> well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.</para>
    </sect1>
    
  <sect1 id="fdl-section4">
    <title>4. MODIFICATIONS</title>
    <para>You may copy and distribute a <link linkend="fdl-modified">Modified Version</link> of the <link linkend="fdl-document">Document</link> under the conditions of sections <link linkend="fdl-section2">2</link> and <link linkend="fdl-section3">3</link> above, provided that you release the Modified Version under precisely this Licence, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:</para>
    
    <itemizedlist mark="opencircle">
      <listitem>
	<formalpara>
	  <title>A</title>
	  <para>Use in the <link linkend="fdl-title-page">Title Page</link> (and on the covers, if any) a title distinct from that of the <link linkend="fdl-document">Document</link>, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>B</title>
	  <para>List on the <link linkend="fdl-title-page">Title Page</link>, as authors, one or more persons or entities responsible for authorship of the modifications in the <link linkend="fdl-modified">Modified Version</link>, together with at least five of the principal authors of the <link linkend="fdl-document">Document</link> (all of its principal authors, if it has less than five).</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>C</title>
	  <para>State on the <link linkend="fdl-title-page">Title Page</link> the name of the publisher of the <link linkend="fdl-modified">Modified Version</link>, as the publisher.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>D</title>
	  <para>Preserve all the copyright notices of the <link linkend="fdl-document">Document</link>.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>E</title>
	  <para>Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>F</title>
	  <para>Include, immediately after the copyright notices, a licence notice giving the public permission to use the <link linkend="fdl-modified">Modified Version</link> under the terms of this Licence, in the form shown in the Addendum below.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>G</title>
	  <para>Preserve in that licence notice the full lists of <link linkend="fdl-invariant"> Invariant Sections</link> and required <link linkend="fdl-cover-texts">Cover Texts</link> given in the <link linkend="fdl-document">Document's</link> licence notice.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>H</title>
	  <para>Include an unaltered copy of this Licence.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>I</title>
	  <para>
	    Preserve the section entitled <quote>History</quote>, and
	    its title, and add to it an item stating at least the
	    title, year, new authors, and publisher of the <link linkend="fdl-modified">Modified Version</link> as given on
	    the <link linkend="fdl-title-page">Title Page</link>.  If
	    there is no section entitled <quote>History</quote> in the
	    <link linkend="fdl-document">Document</link>, create one
	    stating the title, year, authors, and publisher of the
	    Document as given on its Title Page, then add an item
	    describing the Modified Version as stated in the previous
	    sentence.
	  </para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>J</title>
	  <para>Preserve the network location, if any, given in the <link linkend="fdl-document">Document</link> for public access to a <link linkend="fdl-transparent">Transparent</link> copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the <quote>History</quote> section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>K</title>
	  <para>In any section entitled <quote>Acknowledgements</quote> or <quote>Dedications</quote>, preserve the section's title, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>L</title>
	  <para>Preserve all the <link linkend="fdl-invariant">Invariant Sections</link> of the <link linkend="fdl-document">Document</link>, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>M</title>
	  <para>Delete any section entitled <quote>Endorsements</quote>. Such a section may not be included in the <link linkend="fdl-modified">Modified Version</link>.</para>
	</formalpara>
      </listitem>
      
      <listitem>
	<formalpara>
	  <title>N</title>
	  <para>Do not retitle any existing section as <quote>Endorsements</quote> or to conflict in title with any <link linkend="fdl-invariant">Invariant Section</link>.</para>
	</formalpara>
      </listitem>
    </itemizedlist>
    
    <para>If the <link linkend="fdl-modified">Modified Version</link> includes new front-matter sections or appendices that qualify as <link linkend="fdl-secondary">Secondary Sections</link> and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of <link linkend="fdl-invariant">Invariant Sections</link> in the Modified Version's licence notice. These titles must be distinct from any other section titles.</para>
    
    <para>You may add a section entitled <quote>Endorsements</quote>, provided it contains nothing but endorsements of your <link linkend="fdl-modified">Modified Version</link> by various parties--for example, statements of peer review or that the text has been approved by an organisation as the authoritative definition of a standard.</para>
    
    <para>You may add a passage of up to five words as a <link linkend="fdl-cover-texts">Front-Cover Text</link>, and a passage of up to 25 words as a <link linkend="fdl-cover-texts">Back-Cover Text</link>, to the end of the list of <link linkend="fdl-cover-texts">Cover Texts</link> in the <link linkend="fdl-modified">Modified Version</link>. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the <link linkend="fdl-document">Document</link> already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.</para>
    
    <para>The author(s) and publisher(s) of the <link linkend="fdl-document">Document</link> do not by this Licence give permission to use their names for publicity for or to assert or imply endorsement of any <link linkend="fdl-modified">Modified Version </link>.</para>
  </sect1>
    
  <sect1 id="fdl-section5">
    <title>5. COMBINING DOCUMENTS</title>
    <para>You may combine the <link linkend="fdl-document">Document</link> with other documents released under this Licence, under the terms defined in <link linkend="fdl-section4">section 4</link> above for modified versions, provided that you include in the combination all of the <link linkend="fdl-invariant">Invariant Sections</link> of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its licence notice.</para>
    
    <para>The combined work need only contain one copy of this Licence, and multiple identical <link linkend="fdl-invariant">Invariant Sections</link> may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the licence notice of the combined work.</para>
    
    <para>In the combination, you must combine any sections entitled <quote>History</quote> in the various original documents, forming one section entitled <quote>History</quote>; likewise combine any sections entitled <quote>Acknowledgements</quote>, and any sections entitled <quote>Dedications</quote>. You must delete all sections entitled <quote>Endorsements.</quote></para>
    </sect1>
    
  <sect1 id="fdl-section6">
    <title>6. COLLECTIONS OF DOCUMENTS</title>
    <para>You may make a collection consisting of the <link linkend="fdl-document">Document</link> and other documents released under this Licence, and replace the individual copies of this Licence in the various documents with a single copy that is included in the collection, provided that you follow the rules of this Licence for verbatim copying of each of the documents in all other respects.</para>
    
    <para>
      You may extract a single document from such a collection, and
      distribute it individually under this License, provided you
      insert a copy of this License into the extracted document, and
      follow this License in all other respects regarding verbatim
      copying of that document.
    </para>
    </sect1>
    
  <sect1 id="fdl-section7">
    <title>7. AGGREGATION WITH INDEPENDENT WORKS</title>
    <para>A compilation of the <link linkend="fdl-document">Document</link> or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, does not as a whole count as a <link linkend="fdl-modified">Modified Version</link> of the Document, provided no compilation copyright is claimed for the compilation. Such a compilation is called an <quote>aggregate</quote>, and this Licence does not apply to the other self-contained works thus compiled with the Document , on account of their being thus compiled, if they are not themselves derivative works of the Document. If the <link linkend="fdl-cover-texts">Cover Text</link> requirement of <link linkend="fdl-section3">section 3</link> is applicable to these copies of the Document, then if the Document is less than one quarter of the entire aggregate, the Document's Cover Texts may be placed on covers that surround only the Document within the aggregate. Otherwise they must appear on covers around the whole aggregate.</para>
    </sect1>
    
  <sect1 id="fdl-section8">
    <title>8. TRANSLATION</title>
    <para>Translation is considered a kind of modification, so you may distribute translations of the <link linkend="fdl-document">Document</link> under the terms of <link linkend="fdl-section4">section 4</link>. Replacing <link linkend="fdl-invariant"> Invariant Sections</link> with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this Licence provided that you also include the original English version of this Licence. In case of a disagreement between the translation and the original English version of this Licence, the original English version will prevail.</para>
    </sect1>
    
  <sect1 id="fdl-section9">
    <title>9. TERMINATION</title>
    <para>You may not copy, modify, sublicence, or distribute the <link linkend="fdl-document">Document</link> except as expressly provided for under this Licence. Any other attempt to copy, modify, sublicence or distribute the Document is void, and will automatically terminate your rights under this Licence. However, parties who have received copies, or rights, from you under this Licence will not have their licences terminated so long as such parties remain in full compliance.</para>
    </sect1>
    
  <sect1 id="fdl-section10">
    <title>10. FUTURE REVISIONS OF THIS LICENCE</title>
    <para>The <ulink type="http" url="http://www.gnu.org/fsf/fsf.html">Free Software Foundation</ulink> may publish new, revised versions of the GNU Free Documentation Licence from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See <ulink type="http" url="http://www.gnu.org/copyleft">http://www.gnu.org/copyleft/</ulink>.</para>
    
    <para>Each version of the Licence is given a distinguishing version number. If the <link linkend="fdl-document">Document</link> specifies that a particular numbered version of this Licence <quote>or any later version</quote> applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this Licence, you may choose any version ever published (not as a draft) by the Free Software Foundation.</para>
  </sect1>

  <sect1 id="fdl-using">
    <title>Addendum</title>
    <para>To use this Licence in a document you have written, include a copy of the Licence in the document and put the following copyright and licence notices just after the title page:</para>
    
    <blockquote>
      <para>Copyright YEAR YOUR NAME.</para>
      <para>Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation Licence, Version 1.1 or any later version published by the Free Software Foundation; with the <link linkend="fdl-invariant">Invariant Sections</link> being LIST THEIR TITLES, with the <link linkend="fdl-cover-texts">Front-Cover Texts</link> being LIST, and with the <link linkend="fdl-cover-texts">Back-Cover Texts</link> being LIST. A copy of the licence is included in the section entitled <quote>GNU Free Documentation Licence</quote>.</para>
    </blockquote>
      
    <para>If you have no <link linkend="fdl-invariant">Invariant Sections</link>, write <quote>with no Invariant Sections</quote> instead of saying which ones are invariant. If you have no <link linkend="fdl-cover-texts">Front-Cover Texts</link>, write <quote>no Front-Cover Texts</quote> instead of <quote>Front-Cover Texts being LIST</quote>; likewise for <link linkend="fdl-cover-texts">Back-Cover Texts</link>.</para>
    
    <para>If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software licence, such as the <ulink type="http" url="http://www.gnu.org/copyleft/gpl.html"> GNU General Public Licence</ulink>, to permit their use in free software.</para>
  </sect1>
</appendix>  








</book>
