gstreamer/docs/manual/basics-init.xml

<chapter id="chapter-initialisation">
  <title>Initializing <application>GStreamer</application></title>
  <para> 
    When writing a <application>GStreamer</application> application, you can
    simply include <filename class='headerfile'>gst/gst.h</filename> to get 
    access to the library functions.
  </para> 
  <para> 
    Before the <application>GStreamer</application> libraries can be used,
    <function>gst_init</function> has to be called from the main application. 
    This call will perform the necessary initialization of the library as
    well as parse the GStreamer-specific command line options.
  </para>
  <para> 
    A typical program
    &EXAFOOT;
    would have code to initialize GStreamer that
    looks like this:
  </para>

  <programlisting>
<![CDATA[
/* example-begin init.c */

#include <gst/gst.h>

int
main (int argc, char *argv[])
{
  guint major, minor, micro;

  gst_init (&amp;argc, &amp;argv);

  gst_version (&amp;major, &amp;minor, &amp;micro);
  printf ("This program is linked against GStreamer %d.%d.%d\n",
          major, minor, micro);

  return 0;
}
/* example-end init.c */
]]>
  </programlisting>
  <para>
    Use the <symbol>GST_VERSION_MAJOR</symbol>,
    <symbol>GST_VERSION_MINOR</symbol> and <symbol>GST_VERSION_MICRO</symbol>
    macros to get the <application>GStreamer</application> version you are
    building against, or use the function <function>gst_version</function>
    to get the version your application is linked against.
<!--    FIXME: include an automatically generated list of these options. -->
  </para>
  <para>
    It is also possible to call the <function>gst_init</function> function
    with two <symbol>NULL</symbol> arguments, in which case no command line
    options will be parsed by <application>GStreamer</application>.
  </para>
  <sect1>
    <title>The popt interface</title>
    <para>
You can also use a popt table to initialize your own parameters as shown in the
next example:
    </para>
    <programlisting>
/* example-begin popt.c */

#include &lt;gst/gst.h&gt;

int
main(int argc, char *argv[])
{
  gboolean silent = FALSE;
  gchar *savefile = NULL;
  struct poptOption options[] = {
    {"silent",	's',  POPT_ARG_NONE|POPT_ARGFLAG_STRIP,   &amp;silent,   0,
     "do not output status information", NULL},
    {"output",	'o',  POPT_ARG_STRING|POPT_ARGFLAG_STRIP, &amp;savefile, 0,
     "save xml representation of pipeline to FILE and exit", "FILE"},
    POPT_TABLEEND
  };

  gst_init_with_popt_table (&amp;argc, &amp;argv, options);

  printf ("Run me with --help to see the Application options appended.\n");

  return 0;
}
/* example-end popt.c */
    </programlisting>
    <para>
      As shown in this fragment, you can use a <ulink
      url="http://developer.gnome.org/doc/guides/popt/"
      type="http">popt</ulink> table to define your application-specific
      command line options, and pass this table to the
      function <function>gst_init_with_popt_table</function>. Your
      application options will be parsed in addition to the standard
      <application>GStreamer</application> options.
    </para>
  </sect1>

</chapter>