Re: get_toplevel to reach derived toplevel window's members

["Onur Tugcu" <onur tugcu gmail com>]

I'm sorry, ignore it please.

I forgot Gtk::Main in the testcase.

On Dec 22, 2007 1:54 AM, Onur Tugcu <onur tugcu gmail com> wrote:
> Hi,
>
> Say a derived widget's member function has to reach the derived
> toplevel window's member and call its member function.
>
> #include <iostream>
> #include <gtkmm/main.h>
> #include <gtkmm/entry.h>
> #include <gtkmm/textview.h>
> #include <gtkmm/window.h>
> #include <gtkmm/box.h>
>
> struct mywindow;
>
> struct myentry: Gtk::Entry
> {
>   void reach_textview();
> };
>
> struct mywindow: Gtk::Window
> {
>   Gtk::VBox vbox;
>   myentry entry;
>   Gtk::TextView textview;
>
>   mywindow()
>   {
>     vbox.pack_start(textview);
>     vbox.pack_start(entry);
>     add(vbox);
>     show_all();
>   }
> };
>
> void myentry::reach_textview()
> {
>   mywindow* pwin= dynamic_cast<mywindow*>(get_toplevel());
>   pwin-> textview.get_buffer()-> set_text("hello");
> }
>
> int main()
> {
>   mywindow win;
>   win.entry.reach_textview();
> }
>
>
>
> But this causes GLib runtime messages and then a segfault
> (process:18811): GLib-GObject-CRITICAL **:
> /build/buildd/glib2.0-2.14.0/gobject/gtype.c:2242: initialization
> assertion failed, use IA__g_type_init() prior to this function
>
> (process:18811): GLib-CRITICAL **: g_once_init_leave: assertion
> `initialization_value != 0' failed
>
> (process:18811): GLib-GObject-CRITICAL **:
> /build/buildd/glib2.0-2.14.0/gobject/gtype.c:2242: initialization
> assertion failed, use IA__g_type_init() prior to this function
>
> (process:18811): GLib-GObject-CRITICAL **:
> /build/buildd/glib2.0-2.14.0/gobject/gtype.c:2242: initialization
> assertion failed, use IA__g_type_init() prior to this function
>
> (process:18811): GLib-GObject-CRITICAL **:
> /build/buildd/glib2.0-2.14.0/gobject/gtype.c:2242: initialization
> assertion failed, use IA__g_type_init() prior to this function
>
> (process:18811): GLib-GObject-CRITICAL **:
> g_type_add_interface_static: assertion `G_TYPE_IS_INSTANTIATABLE
> (instance_type)' failed
>
> (process:18811): GLib-GObject-CRITICAL **:
> /build/buildd/glib2.0-2.14.0/gobject/gtype.c:2242: initialization
> assertion failed, use IA__g_type_init() prior to this function
>
> (process:18811): GLib-GObject-CRITICAL **:
> /build/buildd/glib2.0-2.14.0/gobject/gtype.c:2242: initialization
> assertion failed, use IA__g_type_init() prior to this function
>
> (process:18811): GLib-GObject-CRITICAL **:
> /build/buildd/glib2.0-2.14.0/gobject/gtype.c:2242: initialization
> assertion failed, use IA__g_type_init() prior to this function
>
> Program received signal SIGSEGV, Segmentation fault.
>
> And gdb says:
>
> (gdb) bt
> #0  0x00002b9b771e79e0 in strlen () from /lib/libc.so.6
> #1  0x00002b9b7449138c in Glib::ustring::operator+= ()
>    from /usr/lib/libglibmm-2.4.so.1
> #2  0x00002b9b744873d9 in Glib::Class::register_derived_type ()
>    from /usr/lib/libglibmm-2.4.so.1
> #3  0x00002b9b732e4385 in Gtk::Window_Class::init ()
>    from /usr/lib/libgtkmm-2.4.so.1
> #4  0x00002b9b732e582c in Gtk::Window::Window ()
>    from /usr/lib/libgtkmm-2.4.so.1
> #5  0x0000000000406a7c in mywindow (this=0x7fff37cf9620) at gtkmain.cpp:22
> #6  0x0000000000406490 in main () at gtkmain.cpp:38
>
>
>
> I will try showing what I'm doing in a simpler scenario:
> #include <iostream>
>
> struct container;
>
> struct widget
> {
>   container* parent;
>   void f(){ std::cout<< "widget::f()"; }
>   virtual ~widget(){}
> };
>
> struct mywidget: widget
> {
>   void reach_widget_two();
> };
>
> struct container: widget{};
> struct bin: container{};
> struct window: bin{};
>
> struct mywindow: window
> {
>   mywidget one;
>   widget two;
> };
>
> void mywidget::reach_widget_two()
> {
>   mywindow* pwin= dynamic_cast<mywindow*>(parent);
>   pwin-> two.f();
> }
>
> int main()
> {
>   mywindow win;
>   win.one.parent= dynamic_cast<container*>(&win);
>   win.two.parent= dynamic_cast<container*>(&win);
>   win.one.reach_widget_two();
> }
>
> output:
> widget::f()
>
>
> Thanks for your time
>