z77.html

gtk_text program sample&eg

        after parsing, you have to combine a pair of flags with
        <span class="STRUCTNAME">POPT_ARG_CALLBACK</span>. For
        example, the following <span class="STRUCTNAME">struct
        poptOption</span> initializer specifies a callback to be
        invoked both before and after argument parsing:
      </p>
      <table border="0" bgcolor="#E0E0E0" width="100%">
        <tr>
          <td>
<pre class="PROGRAMLISTING">
&#13;{ NULL, '\0', POPT_ARG_CALLBACK|POPT_CBFLAG_PRE|POPT_CBFLAG_POST,
  &amp;parse_an_arg_callback, 0, NULL}&#13;
</pre>
          </td>
        </tr>
      </table>
      <p>
        The <span class="STRUCTNAME">opt</span> argument to the
        callback is the <span class="STRUCTNAME">struct
        poptOption</span> corresponding to the most recently-seen
        command line option (you can access the <span class= 
        "STRUCTNAME">val</span> member of this struct to determine
        which option you are looking at). The <span class= 
        "STRUCTNAME">arg</span> argument is the text of any
        argument passed to the command line option; the <span
        class="STRUCTNAME">data</span> argument is the callback
        data, given as the <span class="STRUCTNAME">descrip</span>
        member of the <span class="STRUCTNAME">struct
        poptOption</span> which specified the callback.
      </p>
      <p>
        The <span class="STRUCTNAME">flags</span> argument to <tt
        class="FUNCTION">gnome_init_with_popt_table()</tt> can
        basically be ignored in a Gnome context; the available
        flags are not very useful.
      </p>
      <p>
        If you pass a non-<span class="STRUCTNAME">NULL</span>
        pointer for <span class="STRUCTNAME">return_ctx</span>, the
        final argument to <tt class="FUNCTION">
        gnome_init_with_popt_table()</tt>, the current context will
        be returned; you can use this to extract the non-option
        components of the command line, such as filenames. This is
        done with the function <tt class="FUNCTION">
        poptGetArgs()</tt>---here's an example:
      </p>
      <table border="0" bgcolor="#E0E0E0" width="100%">
        <tr>
          <td>
<pre class="PROGRAMLISTING">
&#13;  char** args;
  poptContext ctx;
  int i;

  bindtextdomain (PACKAGE, GNOMELOCALEDIR);
  textdomain (PACKAGE);

  gnome_init_with_popt_table(APPNAME, VERSION, argc, argv, 
                             options, 0, &amp;ctx);

  args = poptGetArgs(ctx);

  if (args != NULL)
    {
      i = 0;
      while (args[i] != NULL) 
        {
          /* Do something with each argument */
          ++i;
        }
    }

  poptFreeContext(ctx);&#13;
</pre>
          </td>
        </tr>
      </table>
      <p>
        Notice that you must free the <span class="STRUCTNAME">
        poptContext</span> if you ask for it; however, if you pass
        <span class="STRUCTNAME">NULL</span> for <span class= 
        "STRUCTNAME">return_ctx</span> the library will free it for
        you. Also keep in mind that <tt class="FUNCTION">
        poptGetArgs()</tt> will return <span class="STRUCTNAME">
        NULL</span> if there are no arguments on the command line.
      </p>
      <div class="SECT2">
        <h2 class="SECT2">
          <a name="Z78">Argument Parsing in GnomeHello</a>
        </h2>
        <p>
          The GnomeHello application outputs the following if you
          invoke it with the <tt class="APPLICATION">--help</tt>
          option:
        </p>
        <table border="0" bgcolor="#E0E0E0" width="100%">
          <tr>
            <td>
<pre class="PROGRAMLISTING">
&#13;$ ./hello --help
Usage: hello [OPTION...]

GNOME Options
  --disable-sound             Disable sound server usage
  --enable-sound              Enable sound server usage
  --espeaker=HOSTNAME:PORT    Host:port on which the sound server to use is
                              running

Help options
  -?, --help                  Show this help message
  --usage                     Display brief usage message

GTK options
  --gdk-debug=FLAGS           Gdk debugging flags to set
  --gdk-no-debug=FLAGS        Gdk debugging flags to unset
  --display=DISPLAY           X display to use
  --sync                      Make X calls synchronous
  --no-xshm                   Don't use X shared memory extension
  --name=NAME                 Program name as used by the window manager
  --class=CLASS               Program class as used by the window manager
  --gxid_host=HOST
  --gxid_port=PORT
  --xim-preedit=STYLE
  --xim-status=STYLE
  --gtk-debug=FLAGS           Gtk+ debugging flags to set
  --gtk-no-debug=FLAGS        Gtk+ debugging flags to unset
  --g-fatal-warnings          Make all warnings fatal
  --gtk-module=MODULE         Load an additional Gtk module

GNOME GUI options
  -V, --version

Help options
  -?, --help                  Show this help message
  --usage                     Display brief usage message

Session management options
  --sm-client-id=ID           Specify session management ID
  --sm-config-prefix=PREFIX   Specify prefix of saved configuration
  --sm-disable                Disable connection to session manager

GnomeHello options
  -g, --greet                 Say hello to specific people listed on the
                              command line
  -m, --message=MESSAGE       Specify a message other than "Hello, World!"
  --geometry=GEOMETRY         Specify the geometry of the main window
$ &#13;
</pre>
            </td>
          </tr>
        </table>
        <p>
          Almost all of these options are common to all Gnome
          applications; only the last three, labelled "GnomeHello
          options," are specific to GnomeHello. The <tt class= 
          "APPLICATION">--greet</tt> or <tt class="APPLICATION">
          -g</tt> option turns on "greet mode"; GnomeHello will
          expect a list of names on the command line, and create a
          dialog to say hello to each person named. The <tt class= 
          "APPLICATION">--message</tt> option expects a string
          argument which replaces the usual "Hello, World!"
          message; the <tt class="APPLICATION">--geometry</tt>
          option expects a standard X geometry string, specifying
          the position and size of the main application window.
        </p>
        <p>
          Here are the variables and <tt class="APPLICATION">
          popt</tt> table GnomeHello uses to do its argument
          parsing:
        </p>
        <table border="0" bgcolor="#E0E0E0" width="100%">
          <tr>
            <td>
<pre class="PROGRAMLISTING">
&#13;static int greet_mode = FALSE;
static char* message  = NULL;
static char* geometry = NULL;

struct poptOption options[] = {
  {
    "greet",
    'g',
    POPT_ARG_NONE,
    &amp;greet_mode,
    0,
    N_("Say hello to specific people listed on the command line"),
    NULL
  },
  { 
    "message",
    'm',
    POPT_ARG_STRING,
    &amp;message,
    0,
    N_("Specify a message other than \"Hello, World!\""),
    N_("MESSAGE")
  },
  { 
    "geometry",
    '\0',
    POPT_ARG_STRING,
    &amp;geometry,
    0,
    N_("Specify the geometry of the main window"),
    N_("GEOMETRY")
  },
  {
    NULL,
    '\0',
    0,
    NULL,
    0,
    NULL,
    NULL
  }
};
&#13;
</pre>
            </td>
          </tr>
        </table>
        <p>
          And here's the first part of <tt class="FUNCTION">
          main()</tt>, where GnomeHello checks that the arguments
          are properly combined and assembles a list of people to
          greet:
        </p>
        <table border="0" bgcolor="#E0E0E0" width="100%">
          <tr>
            <td>
<pre class="PROGRAMLISTING">
&#13;  GtkWidget* app;
  
  poptContext pctx;

  char** args;
  int i;

  GSList* greet = NULL;

  GnomeClient* client;

  bindtextdomain(PACKAGE, GNOMELOCALEDIR);  
  textdomain(PACKAGE);

  gnome_init_with_popt_table(PACKAGE, VERSION, argc, argv, 
                             options, 0, &amp;pctx);  

  /* Argument parsing */

  args = poptGetArgs(pctx);

  if (greet_mode &amp;&amp; args)
    {
      i = 0;
      while (args[i] != NULL) 
        {
          greet = g_slist_prepend(greet, args[i]);
          ++i;
        }
      /* Put them in order */
      greet = g_slist_reverse(greet); 
    }
  else if (greet_mode &amp;&amp; args == NULL)
    {
      g_error(_("You must specify someone to greet."));
    }
  else if (args != NULL)
    {
      g_error(_("Command line arguments are only allowed with --greet."));
    }
  else
    { 
      g_assert(!greet_mode &amp;&amp; args == NULL);
    }

  poptFreeContext(pctx);
&#13;
</pre>
            </td>
          </tr>
        </table>
        <p>
          Again, complete source for GnomeHello is included in
          Appendix E.
        </p>
      </div>
    </div>
    <div class="NAVFOOTER">
      <br>
      <br>
      <table width="100%" border="0" bgcolor="#ffffff" cellpadding= 
      "1" cellspacing="0">
        <tr>
          <td width="25%" bgcolor="#ffffff" align="left">
            <a href="sec-i18n.html"><font color="#0000ff" size="2">
            <b>&lt;&lt;&lt; Previous</b></font></a>
          </td>
          <td width="25%" colspan="2" bgcolor="#ffffff" align= 
          "center">
            <font color="#0000ff" size="2"><b><a href="ggad.html">
            <font color="#0000ff" size="2"><b>
            Home</b></font></a></b></font>
          </td>
          <td width="25%" bgcolor="#ffffff" align="right">
            <a href="z79.html"><font color="#0000ff" size="2"><b>
            Next &gt;&gt;&gt;</b></font></a>
          </td>
        </tr>
        <tr>
          <td colspan="2" align="left">
            <font color="#000000" size="2"><b>
            Internationalization</b></font>
          </td>
          <td colspan="2" align="right">
            <font color="#000000" size="2"><b>Saving Configuration
            Information</b></font>
          </td>
        </tr>
      </table>
    </div>
  </body>
</html>