Re: gtk_widget_ref() /gtk_widget_unref() ?

[Tristan Van Berkom <vantr touchtunes com>]

> Can someone tell me the aim of gtk_widget_ref/gtk_widget_unref?

g_object_ref/g_object_unref
are methods of the GObjectClass.

I'm not sure about the implementation history
of gtk_widget_ref/unref but I think they were either
wrappers to G_OBJECT(widget)->ref/unref or a seperate
reference count implemented at the GtkWidget level when
GtkWidget was derived from GtkObject. (still is but
GtkObject now is derived from GObject which already
implemets ref/unref etc...).

So in short the GObject is now the base class of
all widgets and the reference count is stored in
the GObject level.

> In online docs (in docs downloaded they are ok...) are signed as deprecated
> in favour of g_widget_ref/g_widget_unref, but they don't say what is their
> use.

when creating an object; your object has a reference
count of 1. if you add your object to a container;
your container will "hold a reference" on that object
(call g_object_ref) untill the container is destroyed or
the object is removed from the container.

If you create an object and add it to a container and
than call g_object_unref on the object; the container
"owns" the object and you dont have the right to depend on
its existance (seeing as you dont "hold a reference" on it
anymore).

When a reference count falls to 0 the object is
finalized (the resources are freed). 

The correct way to destroy widgets you dont need
is to call g_object_unref(G_OBJECT(widget));

Cheers,
        -Tristan