#!/usr/bin/perl -w
use strict;
use diagnostics;

use Gtk2 -init;

my $mw = Gtk2::Window->new();
$mw->signal_connect( 'delete_event' => sub { Gtk2->main_quit; } );

my $button=Gtk2::Button->new_from_stock( 'gtk-add' );

$button->add_events( 'key-press-mask' );
$button->signal_connect( 'clicked' => sub {
  
                                          my ( $widget, $event ) = @_;
                                          action( $widget, $event )

                                       } );

   $mw->add( $button );
   $mw->show_all;
  
   Gtk2->main;
                                      
sub action {
  
   my ( $widget, $event ) = @_;
  
      if ( ($event->state() & GDK_SHIFT_MASK) == GDK_SHIFT_MASK ) {
       
         print "The shift key was pressed\n";
        
      }
      else {
        
         print "The shift key was NOT pressed\n";
                
      }
  
  
}