# setup glib loop
our $loop = Glib::MainLoop->new(undef,0);

# handle tk events
sub tk_loop {
  my $c = Tk::MainWindow->Count;
  if ($c) {
    1 while (DoOneEvent(ALL_EVENTS | DONT_WAIT));
  }
  else {
    $loop->quit;  # quit glib loop if GUI is closed
  }
  $c;
}

Glib::Timeout->add(5,\&tk_loop);  # call tk_loop every 5 ms

$loop->run;