Re: Gtk::Widget::on_hide

[Kjell Ahlstedt <kjell ahlstedt bredband net>]

Yes, G_OBJECT_GET_CLASS(gobject_) dereferences gobject_.
on_hide() should not be called when gobject_ is 0. Two possible reasons 
it is called:

1. There is a bug in gtkmm 3.7.12 and 3.8.0 that can make such a call 
happen.
See https://bugzilla.gnome.org/show_bug.cgi?id=605728#c5
That bug was fixed in 3.8.1.

2. Your program calls Gtk::Widget::on_hide(). You should not do that 
unless you really know what you're doing. on_hide() is the default 
signal handler of the hide signal. If you want to, you can override it 
in a derived class, and wait for it to be called when the hide signal is 
emitted, but don't call it yourself.

Kjell

2013-11-18 15:59, Alan Mazer skrev:
> The G_OBJECT_GET_CLASS macro is probably dereferencing gobject_, e.g., 
> replacing it with gobject_->class or some such...
>
> -- Alan
>
>
> On 11/18/2013 6:53 AM, John Emmas wrote:
> > I'm trying to debug a program which keeps crashing in 
> > 'Gtk::Widget::on_hide()'.  Here's what that function looks like:-
> >
> >     void Gtk::Widget::on_hide()
> >     {
> >       BaseClassType *const base = static_cast<BaseClassType*>(
> >           g_type_class_peek_parent(G_OBJECT_GET_CLASS(gobject_)) // 
> > Get the parent class of the object class (The original underlying C 
> > class).
> >       );
> >
> >       if(base && base->hide)
> >         (*base->hide)(gobj());
> >     }
> >
> > Every time the crash occurs, variable 'gobject_' is always NULL. 
> > Although I'm currently trying to figure out why, the above code looks 
> > (to my untrained eye) as though it should be reasonably well behaved 
> > with a NULL gobject_.  It looks as if that function should be safe, 
> > even when gobject_ is NULL.  Is that a reasonable assessment or just 
> > wishful thinking on my part?
> >
> > John
> > _______________________________________________
> > gtkmm-list mailing list
> > gtkmm-list gnome org
> > https://mail.gnome.org/mailman/listinfo/gtkmm-list
>
> _______________________________________________
> gtkmm-list mailing list
> gtkmm-list gnome org
> https://mail.gnome.org/mailman/listinfo/gtkmm-list