I wrote the following bit of code using Tk: 
use strict;
use Win32::Clipboard;
use Tk;


my $change_mode = \&change_mode;
my $mode = 0;
my $clip = Win32::Clipboard();

my $main = new MainWindow;
$main->Label(-text => 'Clipboard Case Changer'
             )->pack;
$main->Button(-text => 'On/Off Toggle',
              -command => $change_mode
              )->pack;
                         
MainLoop;

sub change_mode {
    $mode = !$mode;
}

#Change clipboard contents to uppercase, if $mode == 1;
while(1) {
    $clip->WaitForChange();
    my $contents = $clip->Get();
    if ($mode) {
        $clip->Set(uc($contents));
    }
}

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Even though I'm new to Tk, I was pretty sure the above code wouldn't work. Sure enough, it doesn't. I'm guessing it's because the infinite loop, outside of the 'MainLoop,' never gets executed. So am I going to need a thread here? I've dabbled with threads in Java. But I'm not familiar with threading at all with Perl and I hear it's kind of a nightmare. Is there a more obvious technique I could be using that I'm missing?

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In reply to Does this Tk program require a thread? by nysus

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