FORK: {
    if ($pid = fork) {
      #Parent here.
      #Child process pid is available in $pid
    } elsif (defined $pid) { #pid is zero here if defined
      #child here
      #parent process pid is available with getppid (Not available with Windows).
    } elsif ($! == EAGAIN) {
      #EAGAIN is supposedly recoverable fork error
      sleep 5;
      redo FORK;
    } else {
      #Weird fork error
      die "Can't fork: $!\n";
    }
  }

##</code><code>##

  if (open(TO, "|-")) {
    print TO $fromparent;
  } else {
    $tochild = <STDIN>;
    #Do whatever with $child
    exit;
  };

##</code><code>##

pipe(FROM_PARENT, TO_CHILD) or die "pipe: $!";
select((select(TO_CHILD), $| = 1))[0]);