Processing show signal

[Esteban Quijano Vincenzi <equijano videotek tv>]

I tried to make a hook function that is connected to the show event of a
widget.
This function should evaluate an expression, and depending on its
result, let the
widget to be shown or not. However, no matter if I return TRUE or FALSE
from the hook function, the widget will always be shown.

How do I know if a hook function connected with gtk_signal_connect(...),
not
gtk_signal_connect_after(...), will be called before the "standard"
function for
that event?

As I know, if a hook function returns FALSE -like when processing
"delete-event"
when closing a GTK program- it will make the default action to be taken.
Is that true
for all event handlers?

By the way, what's the difference between "delete-event" and
"destroy-event"?

Esteban Q.