#!/usr/local/bin/perl

use Tk;
use strict;
use warnings;

my $main = new Tk::MainWindow();

my $entry_test = $main->Entry()->pack();
my $btn_test = $main->Button( -text => ' Test ', 
                              -command => sub { 
                                               my $text = $entry_test->get(); 
                                               eval { utf8::downgrade($text); };
                                               &msg($main, $@) if ($@);                                                                                                 
                                              } )->pack();

sub msg
 {
  my ($parent, $msg) = @_;
  $parent->messageBox( -title => 'Event', -message => $msg, -type => 'ok', -icon => 'info' );
 }


MainLoop();

 „