On Fri, Jul 21, 2006 at 10:22:19PM +0200, Tomasz Jankowski wrote: > > I read few times "Gobject tutorial" provided with GLib's documentation but I > don't understood it enouhg good, maybe because I don't like (and know) > object languages, I know only C++ basics. So these are my questions: > > I. What the Interfaces are? I don't understood their predestination? I > understood them as other type of Methods, but I'm know, that Interfaces > aren't Methods, can someone explain me it?
[quote from Sun] An interface is a contract in the form of a collection of method and constant declarations. When a class implements an interface, it promises to implement all of the methods declared in that interface. [/quote] This sums it up nicely, except in GObject there are other things that can be part of an interface, namely signals. But the principle is the same, an interface is a collection of APIs a class can claim it provides. For example, GtkTreeModel is an interface. So if you write a new tree model it claims `I am a tree model' and it does not have to derive from a specific parent class for that (OK, interface in fact can impose parent class restrictions, but that's a technical detail). C++ has no direct analogue because it has multiple inheritance so it doesn't need it. > II. For example, object "XXX" inherits from object "ZZZ" Objects do not inherit, classes do. > and I defined > *_finalize () functions for object ZZZ, but I didn't define any *finalize > functions for object XXX. What will happen if I'll try to destroy XXX > object? Will ZZZ's *_finalize functions will be used? Yes, it will. Moreover, if the class of XXX *does* define a finalize method, it has to explicitly call the parent's class finalize: G_OBJECT_CLASS(parent_class)->finalize(object); (see Gtk+ source code for examples). > III. What 'GTypeInstance' is? GTypeInstance is a low-level construct in the type system, it is `an instance of something that has a GType'. You should never need it. Yeti -- Anonyms eat their boogers. _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
