Use IO::Handle;

pipe(THISREADHANDLE, THISWRITEHANDLE);

THISWRITEHANDLE->autoflush(1);
THISREADHANDLE->autoflush(1);

if ($processed = fork) {
   close THISWRITEHANDLE;
   while (defined($text = <THISREADHANDLE>)) {
      print $text;
   }
   close THISREADHANDLE;
   waitpid($processed, 0);
} else {
   close THISREADHANDLE;
   print THISWRITEHANDLE "This is a text message";
   exit;
}