#!/usr/bin/perl
use strict;
use threads;
use Thread::Semaphore;

my $semaphore = new Thread::Semaphore;
$semaphore->down;

sub code {
  my $job = $_[0];
  $semaphore->down;
  print "$job\n";
}

foreach (1..10) {
  threads->new(\&code, $_);
}

sleep 5;
$semaphore->up(10);