use strict; $|++;

if( $ARGV[0] eq 'child' )
{
  sleep 1; print STDOUT "stdout1\n";
  sleep 1; print STDOUT "stdout2\n";
  sleep 1; print STDOUT "stdout3\n";
  sleep 1; print STDOUT "stdout4\n";
  exit;
}

use Tk;
use Tk::ROText;
my $mw = MainWindow->new;
my $text = $mw->ROText()->pack( -fill => 'both', -expand => 1 );

use IO::Handle;
my $stdout = IO::Handle->new();

my $pid = open( $stdout, "$0 child |" ) || die;
$stdout->autoflush( 1 );

$mw->fileevent( $stdout, readable => \&read_stdout );

MainLoop;


sub read_stdout
{
  print "read_stdout()\n";
  my $num = $stdout->sysread( my $buffer, 1024 );
  print "sysread() got $num bytes:\n[$buffer]\n";
  $text->insert( 'end', $buffer );
}