Accessing multiple widgets

[Dieter Oelofse <Dieter_o1 Verifone Com>]

I am new to GTK+ development. My problem is how to access multiple widgets from
a callback. I want to take the text of two entry boxes, do some processing in
the callback function that belongs to a button and put the result in a third
entrybox. I just can't seem to figure out how to access these entry boxes from a
callback that does not own any reference to these entry boxes. I don't think
declaring these boxes globally is a good idea, but it might solve my problem.

Thanks
Dieter Oelofse