#!/usr/bin/perl
use strict;
use warnings;

use Proc::Queue 'waitpids', size => 4, debug => 1;

my @pids;
foreach ( 1 .. 10 ) {
    my $f = fork;
    if ( defined($f) and $f == 0 ) {
        print "-- I'm a forked process $$\n";
        sleep rand 5;
        print "-- I'm tired, going away $$\n";
        exit(0);
    }
    push @pids, $f if defined $f;
}

waitpids(@pids);

print "--- FINISHED\n";