#!/usr/bin/perl -w

use strict;
use IPC::Open3;

{
  my %pidlist;

  sub my_open3
  {
    my $pid=open3(@_);
    $pidlist{$pid}=1 if $pid;
    warn "my_open3: Started process $pid\n";
    $pid;
  }

  sub my_killkids
  {
    my($signal) = shift;
    warn "my_killkids: Killing processes ",join(" ",keys %pidlist),"\n";
    kill $signal, keys %pidlist;
  }
  sub my_chld
  {
    my $pid = wait;
    warn "my_chld: Child $pid finished.\n";
    delete $pidlist{$pid};
  }
}


$SIG{CHLD} = \&my_chld;

my_open3(\*STDOUT,\*STDIN,\*STDOUT,"sleep 10");
my_open3(\*STDOUT,\*STDIN,\*STDOUT,"sleep 10");
my_open3(\*STDOUT,\*STDIN,\*STDOUT,"sleep 10");

my_killkids('INT');

sleep(1); sleep(1); sleep(1);

my_killkids('KILL');