use strict;
use X11::Protocol;

my $X = X11::Protocol->new;

my $window = $X->new_rsrc;
$X->CreateWindow ($window,
                  $X->root,         
                  'InputOutput',    
                  0,                
                  0,                
                  0,0,              
                  300,100,          
                  0,                
                  background_pixel => $X->black_pixel,
                  event_mask       => $X->pack_event_mask('Exposure',
                                                          'ButtonPress'),
                 );

my $gc = $X->new_rsrc;
$X->CreateGC ($gc, $window,
              foreground => $X->white_pixel);

$X->{'event_handler'} = sub {
  my %event = @_;
  my $event_name = $event{'name'};

  if ($event_name eq 'Expose') {
    $X->PolyRectangle ($window, $gc, [ 10,10,     
                                       30,20 ]);  
    $X->PolyText8 ($window, $gc,
                   10, 55,    
                   [ 0,  
                     'Hello ... click mouse button to exit.' ]);

  } elsif ($event_name eq 'ButtonPress') {
    exit 0;
  }
};

$X->MapWindow ($window);
for (;;) {
  $X->handle_input;
}