use strict;
use warnings;
use 5.010;

use threads;
use threads::shared;
use Thread::Queue;

my $q : shared;
$q = Thread::Queue->new;    #a Queue is thread safe, which means 
                            #threads can read from it without
                            #interfering with each other.

my @files = (
    'file1',
    'file2',
    'file3',
    'file4',
    'file5',
);


my $thread_count = 2;
my @threads;

for (1 .. $thread_count) {
    my $thread_name = "thread$_";
    push @threads, threads->create(\&do_stuff, $thread_name);
}

$q->enqueue(@files); #...and the starting gun sounds!

for (1 .. $thread_count) {
    $q->enqueue("END_OF_QUEUE");
}

for my $thr (@threads) {
    $thr->join();
}



sub do_stuff {
    my $thr_name = shift;

    while ( (my $file = $q->dequeue) ne "END_OF_QUEUE" ) {

        #$q->dequeue() blocks until there is something to retrieve
        #from the queue.

        say "$thr_name is opening file: $file";

        #doing some work:
        sleep int(rand 4);

        say "$thr_name is is done with: $file";
    }
}


--output:--
thread1 is opening file: file1
thread2 is opening file: file2
thread2 is is done with: file2
thread2 is opening file: file3
thread1 is is done with: file1
thread1 is opening file: file4
thread2 is is done with: file3
thread2 is opening file: file5
thread2 is is done with: file5
thread1 is is done with: file4