Hello,
I made a custom container (sort of a modified notebook widget) following the
gtkmm tutorial, overriding all the functions mentioned in there. The control
has tabs (which are internal children) and pages (added by the top-level
window).
There is no ambiguity in the on_size_request, on_size_allocate,
on_expose_event or the child_type_vfunc overrides. on_add and on_remove also
seems to go well. However while closing the application the debug console is
full of the following messages.
(Commander.exe:7480): GLib-GObject-WARNING **: invalid uninstantiatable type
`(null)' in cast to `GtkContainer'
(Commander.exe:7480): Gtk-CRITICAL **: gtk_container_remove: assertion
`GTK_IS_CONTAINER (container)' failed
(Commander.exe:7480): GLib-GObject-WARNING **: invalid uninstantiatable type
`(null)' in cast to `GtkContainer'
(Commander.exe:7480): Gtk-CRITICAL **: gtk_container_remove: assertion
`GTK_IS_CONTAINER (container)' failed
.................
.................
And not just 4 lines: One for each widget that is a child or grand child of
my custom container. To test, I removed the custom container and added one
of the pages (that contained most number of child widgets) directly to the
top level window (this page also happens to be a custom control derived from
Gtk::VBox). Nothing crashed this time.
On debugging the app what I noticed is while closing gdb detects
segmentation fault in the for_all_vfunc override of the custom container and
stalls. The callstack says this
Thread [1] (Suspended: Signal 'SIGSEGV' received. Description: Segmentation
fault.)
16 gtk_widget_propagate_hierarchy_changed_recurse() 0x61990115
15 MM::CMMNotebook::forall_vfunc() D:\****\Projects\Custom
Controls\UI\MMNotebook.cpp:1059 0x004157b6
14 Gtk::Container_Class::forall_vfunc_callback()
D:\Software\Linux\Source\gtkmm-2.14.3\gtk\gtkmm\container.cc:476
0x00f42ba1
13 gtk_container_forall() 0x617d7a30
12 gtk_widget_propagate_hierarchy_changed_recurse() 0x61990251
11 gtk_box_forall() 0x6179fcfb
10 Gtk::Container_Class::forall_vfunc_callback()
D:\Software\Linux\Source\gtkmm-2.14.3\gtk\gtkmm\container.cc:494
0x00f42c11
9 gtk_container_forall() 0x617d7a30
8 gtk_widget_propagate_hierarchy_changed_recurse() 0x61990251
7 _gtk_widget_propagate_hierarchy_changed() 0x619909da
6 gtk_widget_unparent() 0x61990c5a
5 gtk_bin_remove() 0x6179b36c
4 Gtk::Container_Class::remove_callback()
D:\Software\Linux\Source\gtkmm-2.14.3\gtk\gtkmm\container.cc:177
0x00f4232e
3 g_closure_invoke() 0x63a43955
2 signal_emit_unlocked_R() 0x63a578a2
1 <symbol is not available> 0x00000000
The segmentation fault always happens at this particular line where the
callback is called for this particular widget. But like all other pages
added to this custom container, this widget is also a member of the
top-level window and is not deleted and for that matter does not go out of
scope.
what am I missing?
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