build_gui();   ## sets up the gui_interface
exit;
 
sub build_gui { ## sets up a button and other widget)}

  ## invoked when user pressed a button
  sub event_handler {
  $handle = IO::Socket::INET->new("$host:$port");

  while (<$handle>) # my program freezes here as it
                    # waits for data in the socket
  {
      ## do stuff and then updates the GUI interface
  }
}