IS_A Type Question.

[Pat Suwalski <pat suwalski net>]

Hello,

I'm trying to recycle a callback function. The UI element comes in as a 
GtkWidget*.

The possible types I'm looking at right now are GtkCheckButton and 
GtkCheckMenuItem. Specifically, I'm looking at an attribute they have in 
common, "active."

So, where the attribute is accessed, I'd like to assert if the object is 
of one type or the other, and read the attribute accordingly. In a 
language like Java, I can easily find the is_a relationship. Is there 
something in the gtk library that will do the same? It seems like I've 
looked everywhere! :)

Thanks.
--Pat