#!perl -slw use strict; use threads qw[ async ]; use Thread::Queue; ## A shared var to communicate progess between work thread and TK my $Q = new Thread::Queue; sub work{ open PROC, 'perl -le"$|=1; print and select(undef,undef,undef,0.1) for 1 .. 1000" |' or die $!; while( ) { $Q->enqueue( $_ ); } close PROC; } threads->new( \&work )->detach; ## For lowest memory consumption require (not use) ## Tk::* after you've started the work thread. require Tk::ProgressBar; my $mw = MainWindow->new; my $pb = $mw->ProgressBar()->pack(); my $repeat; $repeat = $mw->repeat( 100 => sub { while( $Q->pending ) { my $progress = $Q->dequeue; return unless $progress; $repeat->cancel if $progress == 100; $pb->value( $progress ) } } ); $mw->MainLoop;