Re: How can I check if a GtkWidget exists?

[David NeÄas <yeti physics muni cz>]

On Fri, Jul 20, 2012 at 10:15:54AM +0200, Miroslav Rajcic wrote:
> Not sure, but perhaps GTK_IS_WIDGET(widget) macro would help.

If you have the pointer to a GObject instance and want to know whether
it is an instance of GtkWidget (including subclasses) then
GTK_IS_WIDGET() is the right thing to use.

But if you use this macro with a random pointer (e.g. one pointing to a
memory location where some GObject might be some time ago) do not expect
anything more useful than a CRITICAL error/crash.

To deal with objects that may or may not exist use one of the several
mechanisms (weak pointers/weak refs/destroy callbacks/...) for keeping
track of the object existence.  And, generally, use these mechanisms to
avoid even the possibility of dangling pointers in your code.

Yeti