[Glade-users] callback -> gpointer user_data problem (perhaps Bug)


I created a GUI window in glade and created a toolbar for it. In the
window I added a GtkTreeView that I like to modify from the toolbar
(delete/add/...). So I created a button on the toolbar and connected a
signal "clicked" to the button. As object I gave the GtkTreeview object
(here: treeview_menu). As I understand the the callback could access now
treeview_menu with a cast of "gpointer user_data". But see what hapens:

my apps sourcecode:
void on_toolbutton_del_clicked (GtkToolButton *toolbutton,
                                gpointer user_data)
  GtkWidget *treeview_menu;

  treeview_menu = (GtkWidget*) user_data;
  delete_table_row (treeview_menu);

This is printed if I click delete:

(e16menuedit2:23698): GLib-GObject-WARNING **: invalid cast from
`GtkToolButton' to `GtkTreeView'

(e16menuedit2:23698): Gtk-CRITICAL **: file gtktreeview.c: line 8693
(gtk_tree_view_get_model): assertion `GTK_IS_TREE_VIEW (tree_view)'

(e16menuedit2:23698): GLib-GObject-WARNING **: invalid cast from
`GtkToolButton' to `GtkTreeView'

(e16menuedit2:23698): Gtk-CRITICAL **: file gtktreeview.c: line 8860
(gtk_tree_view_get_selection): assertion `GTK_IS_TREE_VIEW (tree_view)'

(e16menuedit2:23698): Gtk-CRITICAL **: file gtktreeselection.c: line 362
(gtk_tree_selection_get_selected): assertion `GTK_IS_TREE_SELECTION
(selection)' failed

I use libglade to create the GUI, but looked into the created
interface.c to see what happens here:

This is how Glade connect the callback in interface.c:
  g_signal_connect_swapped ((gpointer) toolbutton_del, "clicked",
                            G_CALLBACK (on_toolbutton_del_clicked),
                            GTK_OBJECT (treeview_menu));

But this doesn't work (at least with libglade) I didn't test the
interface.c source. If I connect the toolbutton myself in sourcecode it
looks like this:

GtkWidget *toolitem1;

toolitem1 = glade_xml_get_widget (main_xml, "toolbutton_del");
g_signal_connect (toolitem1, "clicked",
                  G_CALLBACK (on_toolbutton_del_clicked),

And this works! I'm not a really perfect gkt2 hacker and doesn't
understand all aspects of callback connecting. But why use Glade the
_swapped version to connect callbacks? And why doesn't this work? Same
problems with menubars (and probability other widgets) if I use
user_data to send objects to a widget.

I don't think it's a Glade or libglade bug, because other I think other
people had noticed this before. But where is my problem?


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