#! /usr/bin/env perl
package Foo::Child;
use strict; use warnings;
use FileHandle;
 
sub new {
  my ($class, $pfh, $cfh, $f, @args) = @_;
  bless {pfh => $pfh, cfh => $cfh, f => $f,
         args => [$pfh, @args]}, $class;
}
sub run_and_die {
  my ($fc) = @_;
  close $fc->{cfh};
  $fc->{f}->($fc, @{$fc->{args}});
  close $fc->{pfh};
  exit;
}
sub cfh { $_[0]->{cfh} }
sub pfh { $_[0]->{pfh} }
 
 
package Foo;
use strict; use warnings;
use Socket;
use FileHandle;
 
sub new { bless {children => []}, shift }
sub add_child {
  my ($foo, $f, @args) = @_;
  my ($cfh, $pfh) = (FileHandle->new, FileHandle->new);
  $_->autoflush(1) for ($cfh, $pfh);
  socketpair $cfh, $pfh, AF_UNIX, SOCK_STREAM, PF_UNSPEC
    or die "socketpair: $!";
  push @{$foo->{children}}, Foo::Child->new($pfh, $cfh, $f, @args);
  $foo
}
sub run {
  my ($foo) = @_;
  for my $c (@{$foo->{children}}) {
    for (fork) {
      die "fork failed: $!" unless defined;
      $c->run_and_die unless $_;
      close $c->pfh;
    }
  }
  $foo
}
sub to_all {
  my ($foo, $s) = @_;
  print { $_->cfh } $s for @{$foo->{children}};
  $foo
}
sub from_all {
  my ($foo, @r) = (shift);
  for (@{$foo->{children}}) {
    chomp(my $s = readline($_->cfh));
    push @r, $s
  }
  @r
}
 
package main;
 
sub echo_reverse {
  my ($self, $pfh, $times) = @_;
  while ($times--) {
    chomp(my $line = readline($pfh));
    print $pfh reverse($line) . "\n";
  }
}
 
my $echos = new Foo;
$echos->add_child(\&echo_reverse, 1) for (1..10);
$echos->run;
$echos->to_all("hello world!\n");
print "Read this from a child: $_\n" for $echos->from_all;
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If you want to have a really good time, set the number of children to 1 or 2 and then run this program through the perl debugger. In X, at least, I thought this very cool.

Also, a koders search for socketpair in Perl code.