<?xml version='1.0' encoding="ISO-8859-1"?>
<partintro>
  <para>
    Several useful developer tools have been build around GObject
    technology.  The next sections briefly introduce them and link to
    the respective project pages.
  </para>

  <para>
    For example, writing GObjects is often seen as a tedious task. It
    requires a lot of typing and just doing a copy/paste requires a
    great deal of care. A lot of projects and scripts have been
    written to generate GObject skeleton form boilerplate code, or
    even translating higher-level language into plain C.
  </para>
</partintro>

<chapter id="tools-vala">
  <title>Vala</title>
  <para>
    From the <ulink url="http://live.gnome.org/Vala">Vala
    homepage</ulink> itself: <quote>Vala is a new programming language
    that aims to bring modern programming language features to GNOME
    developers without imposing any additional runtime requirements
    and without using a different ABI compared to applications and
    libraries written in C.</quote>
  </para>

  <para>
    The syntax of Vala is similar to C#. The available compiler
    translates Vala into GObject C code. It can also compile
    non-GObject C, using plain C API.
  </para>
</chapter>

<chapter id="tools-gob">
  <title>GObject builder</title>

  <para>
    In order to help a GObject class developper, one obvious idea is
    to use some sort of templates for the skeletons.  and then run
    them through a special tool to generate the real C files.  <ulink
    url="http://www.5z.com/jirka/gob.html">GOB</ulink> (or GOB2) is
    such a tool. It is a preprocessor which can be used to build
    GObjects with inline C code so that there is no need to edit the
    generated C code.  The syntax is inspired by Java and Yacc or
    Lex. The implementation is intentionally kept simple: the inline C
    code provided by the user is not parsed.
  </para>
</chapter>

<chapter id="tools-ginspector">
    <title>Graphical inspection of GObjects</title>

    <para>
      Yet another tool that you may find helpful when working with
      GObjects is <ulink
      url="http://sourceforge.net/projects/g-inspector">G-Inspector</ulink>. It
      is able to display GLib/GTK+ objects and their properties.
    </para>
</chapter>

<chapter id="tools-refdb">
  <title>Debugging reference count problems</title>

  <para>
    The reference counting scheme used by GObject does solve quite 
    a few memory management problems but also introduces new sources of bugs.
    In large applications, finding the exact spot where the reference count
    of an Object is not properly handled can be very difficult. Hopefully, 
    there exist a tool named <ulink url="http://refdbg.sf.net/">refdbg</ulink>
    which can be used to automate the task of tracking down the location
    of invalid code with regard to reference counting. This application 
    intercepts the reference counting calls and tries to detect invalid behavior. 
    It supports a filter-rule mechanism to let you trace only the objects you are 
    interested in and it can be used together with GDB.
  </para>
  <para>
    <indexterm><primary>g_trap_object_ref</primary></indexterm>
    Note that if GObject has been compiled with <option>--enable-debug=yes</option>,
    it exports a trap variable 
    <programlisting>
static volatile GObject *g_trap_object_ref;
    </programlisting>
    If set to a non-NULL value, <link linkend="g-object-ref">g_object_ref</link>()
    and <link linkend="g-object-unref">g_object_unref</link>() will be intercepted
    when called with that value. 
  </para>
</chapter>
  
<chapter id="tools-gtkdoc">
  <title>Writing API docs</title>

  <para>The API documentation for most of the GLib, GObject, GTK+ and GNOME
  libraries is built with a combination of complex tools. Typically, the part of 
  the documentation which describes the behavior of each function is extracted
  from the specially-formatted source code comments by a tool named gtk-doc which
  generates DocBook XML and merges this DocBook XML with a set of master XML 
  DocBook files. These XML DocBook files are finally processed with xsltproc
  (a small program part of the libxslt library) to generate the final HTML
  output. Other tools can be used to generate PDF output from the source XML.
  The following code excerpt shows what these comments look like.
<programlisting>
/**
 * gtk_widget_freeze_child_notify:
 * @widget: a #GtkWidget
 * 
 * Stops emission of "child-notify" signals on @widget. The signals are
 * queued until gtk_widget_thaw_child_notify() is called on @widget. 
 *
 * This is the analogue of g_object_freeze_notify() for child properties.
 **/
void
gtk_widget_freeze_child_notify (GtkWidget *widget)
{
...
</programlisting>
  </para>
  <para>
  Thorough
  <ulink url="http://developer.gnome.org/arch/doc/authors.html">documentation</ulink> 
  on how to set up and use gtk-doc in your
  project is provided on the GNOME developer website.
  </para>
</chapter>
