Clever way to share file data across threads in Perl
#!/usr/bin/env perl

use strict;
use warnings;

use threads;
use Thread::Queue;

use constant MAX_THREADS => 5;

sub process_data
{
    my( $q ) = @_;
    while( defined( my $data = $q->dequeue() ) )
    {
        print "Thread[".threads->tid()."]: Processing data($data)n";
    }

    print "Thread[".threads->tid()."]: Got end messagen";
} # END process_data

# Main program
{
    my @threads;
    my $q = Thread::Queue->new();
    foreach ( 1 .. MAX_THREAD )
    {
        push( @threads, async { process_data($q) } );
    }

    while( my $line = <STDIN> )
    {
        chop( $line );
        $q->enqueue( $line );
    }

    foreach my $thread ( @threads )
    {
        $q->enqueue( undef );
    }

    foreach my $thread ( @threads )
    {
        $thread->join();
    }
}

use strict;
use warnings;
use Coro;

my $sem = Coro::Semaphore->new(10); # maximum of ten semaphores
while my $line ( <$FILE> ) {
    $sem->down;
    async {
        dostuff($line);
        $sem->up;
    };
}