On Tue, 2009-11-03 at 23:47 -0600, Cody Russell wrote: > On Wed, 2009-11-04 at 06:23 +0100, Javier Jardón wrote: > > The question: why is it normal for GTK widget "constructors" to return > > GtkWidget and not their real type? > > > > For instance I would expect: > > > > gtk_menu_item_new () > > > > To return GtkMenuItem*. But it doesn't, it returns GtkWidget*. > > IMHO is much clear that constructors return their real type, instead > > GtkWidget. But maybe there is a technical reason for this. > > Almost invariably you're going to be doing something with the return > value as a GtkWidget, such as calling gtk_widget_show() on it or packing > it into a container. If that method above returned GtkMenuItem* then > that guarantees a cast, whereas if it returns a GtkWidget* then it may > just get packed into a container and that's the end of it.
What Cody is trying to say is that the pointer type returned is a convention for convenience, since C doesn't have the idea of type inheritance. If you were to call G_OBJECT_TYPE() it would return GTK_TYPE_MENU_ITEM. -- Danielle Madeley Collabora Ltd., Melbourne, Australia http://www.collabora.co.uk/ _______________________________________________ gtk-devel-list mailing list gtk-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-devel-list
