use Tk;

my $var = foo();
print "profil:" . $$var;
#print "profil:" . $var;

sub foo(){

	my $text = "Welches Profil soll bearbeitet werden?";
	my $mw = tkinit(-title=> 'Profil');
	
	my $frame1 = $mw -> Frame() -> pack();
	$frame1->Label( -text => $text)->pack( -side => 'left' );
	
	my $campus_frame = $mw->Frame()->pack();
    my $campus_but = $campus_frame -> Button(-text=>"HAW_Campus", -command => sub {$mw->destroy(); my $var = "A"; return \$var}) -> pack();
    #bzw. ohne \
    $mw->focusForce();
    $campus_but->focus();
    
	MainLoop();
}

my $var = 'X';
foo(\$var);
print $var;

sub foo
{
   my $out = shift;
   # ..
   my $campus_but = $campus_frame -> Button(-text=>"HAW_Campus", -command => sub {$mw->destroy(); $$out = 'A'; }) -> pack();
   # ...    
}