use strict;
use Tk;
use Win32::MMF::Shareable;

print "Process starting...\n";

my $ns = tie my $wait, 'Win32::MMF::Shareable', 'wait' or die;
$wait = 0;

my $mw = MainWindow->new;
$mw->Button( -text => '$wait',                   -command => sub { print "\$wait is $wait\n" } )->pack;
$mw->Button( -text => 'waitVariable( \\$wait )', -command => \&start )->pack;
$mw->Button( -text => 'local $wait++',           -command => \&stop  )->pack;
$mw->Button( -text => 'remote $wait++',          -command => sub{ system "tkremote.pl" } )->pack;

MainLoop;

sub start
{
  print "waiting for \$wait (was $wait)\n";
  $mw->waitVariable( \$wait );
  print "finished waiting for \$wait (is now $wait)\n";
}

sub stop
{
  print "\$wait++ by pid $$\n";
  $wait++;
}

##</code><code>##

use strict;
use Tk;
use Win32::MMF::Shareable;

tie my $wait, 'Win32::MMF::Shareable', 'wait' or die;
print "Remote process $$ increment \$wait...\n";
$wait++;

##</code><code>##

Process starting...                 # 3008 is pid of main

3008 FETCHING...                    # pressed waitVariable
waiting for $wait (was 0)

$wait++ by pid 3008                 # pressed local++
3008 FETCHING...
3008 FETCHING...
3008 FETCHING...
finished waiting for $wait (is now 1)

3008 FETCHING...
waiting for $wait (was 1)
Remote process 3808 increment $wait...  # pressed remote++
3808 FETCHING...             # remote process incremented $wait

3008 FETCHING...             # pressed 'wait'
$wait is 2