my $thr = threads->create(\&function);
 $thr->join;

sub function {
}

##</code><code>##

use threads;
use threads::shared;
use Thread::Semaphore;

my $init = 0;
my $sem:shared;
$sem = new Thread::Semaphore($init);

my $thr = threads->new(\& process );

$sem->down;

sub process {

	lock($sem);
	$sem->up ;
	return;
	
}