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

#set up our window and some interactive feature
my $mw = Tk::MainWindow->new();
my $button = $mw->Button( -text => 'Pop', -command => sub {print "pop!\n";} )->pack();

#set up our periodic task.
#this executes faithfully every x milliseconds
$mw->repeat(5000, \&waiting );

MainLoop;

sub waiting {
    print "waiting...\n";
}