#! perl -slw
# This is perl, v5.10.1 (*) built for x86_64-linux-gnu-thread-multi
use strict;
use threads;
use Thread::Conveyor;

my $belt = Thread::Conveyor->new( {
    maxboxes => 50,
    minboxes => 25,
    optimize => 'memory', # or 'cpu'
});

threads->new(sub {
    print while defined( $_ = $belt->take );
},
{ stack_size => 4096 })->detach;

$belt->put( $_ ) for 1 .. 10;
$belt->put( undef );