Thread::Queue

See the current Perl documentation for Thread::Queue.

Here is our local, out-dated (pre-5.6) version:

Thread::Queue - thread-safe queues

    use Thread::Queue;
    my $q = new Thread::Queue;
    $q->enqueue("foo", "bar");
    my $foo = $q->dequeue;    # The "bar" is still in the queue.
    my $foo = $q->dequeue_nb; # returns "bar",
    

    


A queue, as implemented by Thread::Queue is a thread-safe data structure much like a list. Any number of threads can
safely add elements to the end of the list, or remove elements from the
head of the list. (Queues don't permit adding or removing elements from the
middle of the list)



FUNCTIONS AND METHODS

new


The new function creates a new empty queue.

enqueue LIST


The enqueue method adds a list of scalars on to the end of the queue. The queue will
grow as needed to accomodate the list.

dequeue


The dequeue method removes a scalar from the head of the queue and returns it. If the
queue is currently empty, dequeue will block the thread until another thread enqueues a scalar.

dequeue_nb


The dequeue_nb method, like the dequeue method, removes a scalar from the head of the queue and returns it. Unlike dequeue, though,
dequeue_nb won't block if the queue is empty, instead returning
undef.

pending


The pending method returns the number of items still in the queue. (If there can be
multiple readers on the queue it's best to lock the queue before checking
to make sure that it stays in a consistent state)




SEE ALSO

Thread
  
=cut


sub new { my $class = shift; return bless [@_], $class; }


sub dequeue { use attrs 
qw(locked method); my $q = shift;
cond_wait perlop
until @$q; return shift @$q; }


sub dequeue_nb { use attrs 
qw(locked method); my $q = shift; if
(@$q) { return shift @$q; } else { return undef; } }


sub enqueue { use attrs 
qw(locked method); my perlop = shift; 
push(@$q, @_) and cond_broadcast $q; }


sub pending { use attrs 
qw(locked method); my perlop = shift; return 
scalar(@$q); }


1;