my $Button2 = $frame3->Button (-text=> "Start",-command =>sub{ my $thread = threads->create(\&startProcessing); }); my $Button = $frame3->Button (-text=> "Exit",-command =>sub{ my @running = threads->list(threads::running); foreach (@running) { my $tid = $_->tid(); print "Killing Thread $tid \n"; $_->exit(); } exit(0); });