#!/usr/bin/perl

use strict;
use warnings;

use Tk;

use threads;
use threads::shared;

my $mw = new MainWindow;

my $button = $mw->Button('-relief' => 'raised',
						 '-text' => 'CreateNumbers',
						 '-command' => sub
						 {
							 &createNumberThread(0);
						 });

$button->pack();

MainLoop();


BEGIN
{
	my $nb_thread = undef;
	my $run :shared = 1;
	
	sub createNumberThread
    {
		my $nb = $_[0];
		

		# delete currently active thread if one is available
		if( defined $nb_thread )
		{
			$run = 0;
		}
		
		$nb_thread = threads->new(\&createNumbers, $nb);
		$nb_thread->detach();
		$run = 1;

		sub createNumbers
		{
			my $nb = $_[0];

			while($run)
			{
				print $nb . "\n";
				$nb++;
			}	
		}
	}
}

##</code><code>##

Attempt to free non-existent shared string '_XEvent_', Perl interpreter: 0x1ca69ac at c:/Perl/site/lib/Tk/Widget.pm line 98 during global destruction.
Free to wrong pool 1ca6060 not 246f88 at c:/Perl/site/lib/Tk/Widget.pm line 98 during global destruction.