socketpair(CHILD, PARENT, AF_UNIX, SOCK_STREAM, PF_UNSPEC)
                                or  die "socketpair: $!";


##</code><code>##


#!/usr/bin/perl -w
    # pipe1 - bidirectional communication using two pipe pairs
    #         designed for the socketpair-challenged

    use IO::Handle;

    pipe(PARENT_RDR, CHILD_WTR);
    pipe(CHILD_RDR,  PARENT_WTR);

    CHILD_WTR->autoflush(1);
    PARENT_WTR->autoflush(1);

    if ($pid = fork) {

       close PARENT_RDR; close PARENT_WTR;

       send_message(CHILD_WTR,HELLO,1234);

       my ($code1,$msg1) = receive_message(CHILD_RDR);
       print "Parent Received:" . $code1 . "\t" . $msg1 . "\n";

       close CHILD_RDR; close CHILD_WTR;

       waitpid($pid,0);
    }
    else {

        die "cannot fork: $!" unless defined $pid;
        close CHILD_RDR; close CHILD_WTR;

        my ($code,$msg) = receive_message(PARENT_RDR);

        print "Child Received:" . $code . "\t" . $msg . "\n";

        send_message(PARENT_WTR,Hi,1234);

       close PARENT_RDR; close PARENT_WTR;
       exit;

    }


    sub send_message {

     my $handle  = shift;
     my $code    = shift;
     my $msg   = shift;

     $message = join(':' , $code,$msg);

     print $handle $message;

    }

   sub receive_message {

      my $handle = shift;
      my $msg;

      chomp($msg = <$handle>);

      ($code,$msg) = split (/:/,$msg);

      return ($code,$msg);
    }