#!/usr/bin/perl -w
#

# Libraries
use strict;
use warnings;
use threads;
use Tk;
use Tk::Font;
use Tk::ROText;


# Main Program
my $mw  = new MainWindow(-title => 'Tk thread example');
my $fnt = $mw->Font(-family => 'tahoma', -size => '24');
my $btn = $mw->Button(-text => 'Press Me', -font => $fnt)->pack(-fill => 'x');
$btn->configure(-bg => '#ff7f3f', -command => \&button_press);
my $txt = $mw->ROText(-bg => 'white')->pack(-fill => 'both');
$mw->bind('<Escape>' => sub { exit });
$mw->repeat(1000 => \&gui_loop);
MainLoop;


# Subroutines
sub gui_loop {
    $txt->insert('end', sprintf "Time is %s\n", scalar localtime time());
    $txt->see('end');
}


sub button_press {
    my $sthread = threads->new(sub { worker_thread() });
    $sthread->detach();

    # Here we "return immediately" :)
    return;
}


sub worker_thread {
    my $tid = threads->tid;

    # But DON'T do this ... !!!
    # my $thread_mw = new MainWindow();

    for (my $i = 0; $i < 1024; $i++) {
        printf "Thread %s:  Doing more work ...\n", $tid;
        sleep 1;
    }
}