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Jarkko Hietaniemi > perl-5.7.3 > threads



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Module Version: 0.05   Source   Latest Release: perl-5.8.8


threads - Perl extension allowing use of interpreter based threads from perl


use threads;

sub start_thread { print "Thread started\n"; }

my $thread = threads->create("start_thread","argument");

$thread->create(sub { print "I am a thread"},"argument");



$thread = threads->self();

threads->tid(); threads->self->tid();



Perl 5.6 introduced something called interpreter threads. Interpreter threads are different from "5005threads" (the thread model of Perl 5.005) by creating a new perl interpreter per thread and not sharing any data or state between threads.

Prior to perl 5.8 this has only been available to people embedding perl and for emulating fork() on windows.

The threads API is loosely based on the old API. It is very important to note that variables are not shared between threads, all variables are per default thread local. To use shared variables one must use threads::shared.

It is also important to note that you preferably enable threads by doing use threads as early as possible and that it is not possible to enable threading inside an eval ""; In particular, if you are intending to share variables with threads::shared, you must use threads before you use threads::shared and threads will emit a warning if you do it the other way around.

$thread = threads->create(function, LIST)

This will create a new thread with the entry point function and give it LIST as parameters. It will return the corresponding threads object.


This will wait for the corresponding thread to join. When it finishes join will return the return values of the entry point function. If a thread has been detached, join will return without wait.


Will throw away the return value from the thread and make it non-joinable.


This will return the object for the current thread.


This will return the id of the thread. threads->self->tid() is a quick way to get current thread id.


Fix so the return value is returned when you join.
Add join_all.
Fix memory leaks!


Arthur Bergman <arthur at>

threads is released under the same license as Perl.

Thanks to

Richard Soderberg <rs at> Helping me out tons, trying to find reasons for races and other weird bugs!

Simon Cozens <simon at> Being there to answer zillions of annoying questions

Rocco Caputo <troc at>

Vipul Ved Prakash <mail at> Helping with debugging.

please join for more information


creating a thread from within a thread is unsafe under win32
PERL_OLD_SIGNALS are not threadsafe, will not be.


perl, threads::shared, perlcall, perlembed, perlguts

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