Question

I am using Glade-3. I made this tool:

I saved the project with the name tut.glade and opened the file in a text editor, here’s the code of it:

<?xml version="1.0"?>
<interface>
  <requires lib="gtk+" version="2.16"/>
  <!-- interface-naming-policy project-wide -->
  <object class="GtkListStore" id="liststore1"/>
  <object class="GtkWindow" id="Home">
    <property name="destroy_with_parent">True</property>
    <signal name="destroy" handler="gtk_main_quit"/>
    <child>
      <object class="GtkVBox" id="vbox1">
        <property name="visible">True</property>
        <property name="orientation">vertical</property>
        <child>
          <object class="GtkHBox" id="hbox1">
            <property name="visible">True</property>
            <child>
              <object class="GtkScrolledWindow" id="scrolledwindow1">
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="hscrollbar_policy">automatic</property>
                <property name="vscrollbar_policy">automatic</property>
                <child>
                  <object class="GtkTreeView" id="treeview2">
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
                    <property name="model">liststore1</property>
                  </object>
                </child>
              </object>
              <packing>
                <property name="position">0</property>
              </packing>
            </child>
            <child>
              <object class="GtkVButtonBox" id="vbuttonbox2">
                <property name="visible">True</property>
                <property name="orientation">vertical</property>
                <property name="spacing">2</property>
                <property name="layout_style">center</property>
                <child>
                  <object class="GtkButton" id="button1">
                    <property name="label">gtk-goto-top</property>
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
                    <property name="receives_default">True</property>
                    <property name="use_stock">True</property>
                  </object>
                  <packing>
                    <property name="expand">False</property>
                    <property name="fill">False</property>
                    <property name="position">0</property>
                  </packing>
                </child>
                <child>
                  <object class="GtkButton" id="button2">
                    <property name="label">gtk-go-up</property>
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
                    <property name="receives_default">True</property>
                    <property name="use_stock">True</property>
                  </object>
                  <packing>
                    <property name="expand">False</property>
                    <property name="fill">False</property>
                    <property name="position">1</property>
                  </packing>
                </child>
                <child>
                  <object class="GtkButton" id="button3">
                    <property name="label">gtk-add</property>
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
                    <property name="receives_default">True</property>
                    <property name="use_stock">True</property>
                  </object>
                  <packing>
                    <property name="expand">False</property>
                    <property name="fill">False</property>
                    <property name="position">2</property>
                  </packing>
                </child>
                <child>
                  <object class="GtkButton" id="button4">
                    <property name="label">gtk-remove</property>
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
                    <property name="receives_default">True</property>
                    <property name="use_stock">True</property>
                  </object>
                  <packing>
                    <property name="expand">False</property>
                    <property name="fill">False</property>
                    <property name="position">3</property>
                  </packing>
                </child>
                <child>
                  <object class="GtkButton" id="button5">
                    <property name="label">gtk-go-down</property>
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
                    <property name="receives_default">True</property>
                    <property name="use_stock">True</property>
                  </object>
                  <packing>
                    <property name="expand">False</property>
                    <property name="fill">False</property>
                    <property name="position">4</property>
                  </packing>
                </child>
                <child>
                  <object class="GtkButton" id="button6">
                    <property name="label">gtk-goto-bottom</property>
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
                    <property name="receives_default">True</property>
                    <property name="use_stock">True</property>
                  </object>
                  <packing>
                    <property name="expand">False</property>
                    <property name="fill">False</property>
                    <property name="position">5</property>
                  </packing>
                </child>
              </object>
              <packing>
                <property name="position">1</property>
              </packing>
            </child>
            <child>
              <object class="GtkVBox" id="vbox2">
                <property name="visible">True</property>
                <property name="orientation">vertical</property>
                <child>
                  <object class="GtkViewport" id="viewport1">
                    <property name="visible">True</property>
                    <property name="resize_mode">queue</property>
                    <child>
                      <object class="GtkAlignment" id="alignment1">
                        <property name="width_request">0</property>
                        <property name="height_request">0</property>
                        <property name="visible">True</property>
                        <property name="xscale">0</property>
                        <property name="yscale">0</property>
                        <child>
                          <object class="GtkFrame" id="frame1">
                            <property name="visible">True</property>
                            <property name="label_xalign">0</property>
                            <property name="shadow_type">in</property>
                            <child>
                              <object class="GtkDrawingArea" id="drawingarea1">
                                <property name="width_request">300</property>
                                <property name="height_request">200</property>
                                <property name="visible">True</property>
                              </object>
                            </child>
                            <child type="label_item">
                              <placeholder/>
                            </child>
                          </object>
                        </child>
                      </object>
                    </child>
                  </object>
                  <packing>
                    <property name="position">0</property>
                  </packing>
                </child>
                <child>
                  <object class="GtkHButtonBox" id="hbuttonbox1">
                    <property name="visible">True</property>
                    <property name="spacing">2</property>
                    <property name="homogeneous">True</property>
                    <property name="layout_style">center</property>
                    <child>
                      <object class="GtkCheckButton" id="checkbutton2">
                        <property name="label" translatable="yes">Show points</property>
                        <property name="visible">True</property>
                        <property name="can_focus">True</property>
                        <property name="receives_default">False</property>
                        <property name="draw_indicator">True</property>
                      </object>
                      <packing>
                        <property name="expand">False</property>
                        <property name="fill">False</property>
                        <property name="position">0</property>
                      </packing>
                    </child>
                    <child>
                      <object class="GtkCheckButton" id="checkbutton1">
                        <property name="label" translatable="yes">Show lines</property>
                        <property name="visible">True</property>
                        <property name="can_focus">True</property>
                        <property name="receives_default">False</property>
                        <property name="draw_indicator">True</property>
                      </object>
                      <packing>
                        <property name="expand">False</property>
                        <property name="fill">False</property>
                        <property name="position">1</property>
                      </packing>
                    </child>
                  </object>
                  <packing>
                    <property name="expand">False</property>
                    <property name="position">1</property>
                  </packing>
                </child>
              </object>
              <packing>
                <property name="position">2</property>
              </packing>
            </child>
          </object>
          <packing>
            <property name="position">1</property>
          </packing>
        </child>
        <child>
          <object class="GtkStatusbar" id="statusbar1">
            <property name="visible">True</property>
            <property name="spacing">2</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="pack_type">end</property>
            <property name="position">0</property>
          </packing>
        </child>
      </object>
    </child>
  </object>
</interface>

Then I made a C program named as tut.c which has the following code:

#include <gtk/gtk.h>

int
main( int    argc,
      char **argv )
{
    GtkBuilder *builder;
    GtkWidget  *window;
    GError     *error = NULL;

    /* Init GTK+ */
    gtk_init( &argc, &argv );

    /* Create new GtkBuilder object */
    builder = gtk_builder_new();
    /* Load UI from file. If error occurs, report it and quit application.
 *      * Replace "tut.glade" with your saved project. */
    if( ! gtk_builder_add_from_file( builder, "tut.glade", &error ) )
    {
        g_warning( "%s", error->message );
        g_free( error );
        return( 1 );
    }

    /* Get main window pointer from UI */
    window = GTK_WIDGET( gtk_builder_get_object( builder, "window1" ) );

    /* Connect signals */
    gtk_builder_connect_signals( builder, NULL );

    /* Destroy builder, since we don't need it anymore */
    g_object_unref( G_OBJECT( builder ) );

    /* Show window. All other widgets are automatically shown by GtkBuilder */
    gtk_widget_show( window );

    /* Start main loop */
    gtk_main();

    return( 0 );
}

I then compiled it using

gcc -o tut tut.c $(pkg-config --cflags --libs gtk+-2.0 gmodule-2.0)

then I got the executable file named as tut. I executed it using

./tut

and I got this error:

(tut:19516): Gtk-CRITICAL **: gtk_widget_show: assertion `GTK_IS_WIDGET (widget)' failed

Answer 1

You’re asking for the object named "window1" but there is nothing like that in your tut.glade file. There’s only one window in that XML:

<object class="GtkWindow" id="Home">

So try replacing this:

window = GTK_WIDGET( gtk_builder_get_object( builder, "window1" ) );

with this:

window = GTK_WIDGET( gtk_builder_get_object( builder, "Home" ) );

And maybe a NULL check on window would be a good idea too.