How to access Window Manager protocol

[Laurent Besson <laurent besson st com>]

Hi Folks,

I'm quite new to Gtk-Perl and I was wondering how to get a window which
can't be closed by the window manager.

Back in the old days when I was using Tk, I used to do:

$top = MainWindow->new;
$top->protocol(WM_DELETE_WINDOW,sub { } );

and that was it!

Searching in GTK documentation and also in the excellent tutorial by 
Stephen Wilhelm, I have not been able to find what I'm searching for.

Any clue ?

Laurent.