9 my $XS_VERSION = $VERSION;
10 $VERSION = eval $VERSION;
14 # Verify this Perl supports threads
16 if (! $Config{useithreads}) {
17 die("This Perl not built to support threads\n");
20 # Complain if 'threads' is loaded after 'threads::shared'
21 if ($threads::shared::threads_shared) {
23 Warning, threads::shared has already been loaded. To
24 enable shared variables, 'use threads' must be called
25 before threads::shared or any module that uses it.
31 # Declare that we have been loaded
32 $threads::threads = 1;
36 XSLoader::load('threads', $XS_VERSION);
43 my $class = shift; # Not used
45 # Exported subroutines
46 my @EXPORT = qw(async);
49 while (my $sym = shift) {
50 if ($sym =~ /^(?:stack|exit)/i) {
51 if (defined(my $arg = shift)) {
52 if ($sym =~ /^stack/i) {
53 threads->set_stack_size($arg);
55 $threads::thread_exit_only = $arg =~ /^thread/i;
59 Carp::croak("threads: Missing argument for option: $sym");
62 } elsif ($sym =~ /^str/i) {
63 import overload ('""' => \&tid);
65 } elsif ($sym =~ /^(?:all|yield)$/) {
66 push(@EXPORT, qw(yield));
70 Carp::croak("threads: Unknown import option: $sym");
74 # Export subroutine names
75 my $caller = caller();
76 foreach my $sym (@EXPORT) {
78 *{$caller.'::'.$sym} = \&{$sym};
81 # Set stack size via environment variable
82 if (exists($ENV{'PERL5_ITHREADS_STACK_SIZE'})) {
83 threads->set_stack_size($ENV{'PERL5_ITHREADS_STACK_SIZE'});
90 # Exit from a thread (only)
93 my ($class, $status) = @_;
94 if (! defined($status)) {
101 Carp::croak("Usage: threads->exit(status)");
104 $class->set_thread_exit_only(1);
108 # 'Constant' args for threads->list()
110 sub threads::running { 1 }
111 sub threads::joinable { 0 }
113 # 'new' is an alias for 'create'
116 # 'async' is a function alias for the 'threads->create()' method
119 unshift(@_, 'threads');
120 # Use "goto" trick to avoid pad problems from 5.8.1 (fixed in 5.8.2)
124 # Thread object equality checking
127 '!=' => sub { ! equal(@_) },
137 threads - Perl interpreter-based threads
141 This document describes threads version 1.58
145 use threads ('yield',
146 'stack_size' => 64*4096,
147 'exit' => 'threads_only',
152 print('Thread started: ', join(' ', @args), "\n");
154 my $thr = threads->create('start_thread', 'argument');
157 threads->create(sub { print("I am a thread\n"); })->join();
159 my $thr2 = async { foreach (@files) { ... } };
161 if (my $err = $thr2->error()) {
162 warn("Thread error: $err\n");
165 # Invoke thread in list context (implicit) so it can return a list
166 my ($thr) = threads->create(sub { return (qw/a b c/); });
167 # or specify list context explicitly
168 my $thr = threads->create({'context' => 'list'},
169 sub { return (qw/a b c/); });
170 my @results = $thr->join();
174 # Get a thread's object
175 $thr = threads->self();
176 $thr = threads->object($tid);
179 $tid = threads->tid();
183 # Give other threads a chance to run
187 # Lists of non-detached threads
188 my @threads = threads->list();
189 my $thread_count = threads->list();
191 my @running = threads->list(threads::running);
192 my @joinable = threads->list(threads::joinable);
194 # Test thread objects
195 if ($thr1 == $thr2) {
199 # Manage thread stack size
200 $stack_size = threads->get_stack_size();
201 $old_size = threads->set_stack_size(32*4096);
203 # Create a thread with a specific context and stack size
204 my $thr = threads->create({ 'context' => 'list',
205 'stack_size' => 32*4096,
206 'exit' => 'thread_only' },
209 # Get thread's context
210 my $wantarray = $thr->wantarray();
212 # Check thread's state
213 if ($thr->is_running()) {
216 if ($thr->is_joinable()) {
220 # Send a signal to a thread
221 $thr->kill('SIGUSR1');
228 Perl 5.6 introduced something called interpreter threads. Interpreter threads
229 are different from I<5005threads> (the thread model of Perl 5.005) by creating
230 a new Perl interpreter per thread, and not sharing any data or state between
233 Prior to Perl 5.8, this has only been available to people embedding Perl, and
234 for emulating fork() on Windows.
236 The I<threads> API is loosely based on the old Thread.pm API. It is very
237 important to note that variables are not shared between threads, all variables
238 are by default thread local. To use shared variables one must also use
244 It is also important to note that you must enable threads by doing C<use
245 threads> as early as possible in the script itself, and that it is not
246 possible to enable threading inside an C<eval "">, C<do>, C<require>, or
247 C<use>. In particular, if you are intending to share variables with
248 L<threads::shared>, you must C<use threads> before you C<use threads::shared>.
249 (C<threads> will emit a warning if you do it the other way around.)
253 =item $thr = threads->create(FUNCTION, ARGS)
255 This will create a new thread that will begin execution with the specified
256 entry point function, and give it the I<ARGS> list as parameters. It will
257 return the corresponding threads object, or C<undef> if thread creation failed.
259 I<FUNCTION> may either be the name of a function, an anonymous subroutine, or
262 my $thr = threads->create('func_name', ...);
264 my $thr = threads->create(sub { ... }, ...);
266 my $thr = threads->create(\&func, ...);
268 The C<-E<gt>new()> method is an alias for C<-E<gt>create()>.
272 This will wait for the corresponding thread to complete its execution. When
273 the thread finishes, C<-E<gt>join()> will return the return value(s) of the
274 entry point function.
276 The context (void, scalar or list) for the return value(s) for C<-E<gt>join()>
277 is determined at the time of thread creation.
279 # Create thread in list context (implicit)
280 my ($thr1) = threads->create(sub {
281 my @results = qw(a b c);
285 my $thr1 = threads->create({'context' => 'list'},
287 my @results = qw(a b c);
290 # Retrieve list results from thread
291 my @res1 = $thr1->join();
293 # Create thread in scalar context (implicit)
294 my $thr2 = threads->create(sub {
298 # Retrieve scalar result from thread
299 my $res2 = $thr2->join();
301 # Create a thread in void context (explicit)
302 my $thr3 = threads->create({'void' => 1},
303 sub { print("Hello, world\n"); });
304 # Join the thread in void context (i.e., no return value)
307 See L</"THREAD CONTEXT"> for more details.
309 If the program exits without all threads having either been joined or
310 detached, then a warning will be issued.
312 Calling C<-E<gt>join()> or C<-E<gt>detach()> on an already joined thread will
313 cause an error to be thrown.
317 Makes the thread unjoinable, and causes any eventual return value to be
318 discarded. When the program exits, any detached threads that are still
319 running are silently terminated.
321 If the program exits without all threads having either been joined or
322 detached, then a warning will be issued.
324 Calling C<-E<gt>join()> or C<-E<gt>detach()> on an already detached thread
325 will cause an error to be thrown.
327 =item threads->detach()
329 Class method that allows a thread to detach itself.
331 =item threads->self()
333 Class method that allows a thread to obtain its own I<threads> object.
337 Returns the ID of the thread. Thread IDs are unique integers with the main
338 thread in a program being 0, and incrementing by 1 for every thread created.
342 Class method that allows a thread to obtain its own ID.
346 If you add the C<stringify> import option to your C<use threads> declaration,
347 then using a threads object in a string or a string context (e.g., as a hash
348 key) will cause its ID to be used as the value:
350 use threads qw(stringify);
352 my $thr = threads->create(...);
353 print("Thread $thr started...\n"); # Prints out: Thread 1 started...
355 =item threads->object($tid)
357 This will return the I<threads> object for the I<active> thread associated
358 with the specified thread ID. Returns C<undef> if there is no thread
359 associated with the TID, if the thread is joined or detached, if no TID is
360 specified or if the specified TID is undef.
362 =item threads->yield()
364 This is a suggestion to the OS to let this thread yield CPU time to other
365 threads. What actually happens is highly dependent upon the underlying
366 thread implementation.
368 You may do C<use threads qw(yield)>, and then just use C<yield()> in your
371 =item threads->list()
373 =item threads->list(threads::all)
375 =item threads->list(threads::running)
377 =item threads->list(threads::joinable)
379 With no arguments (or using C<threads::all>) and in a list context, returns a
380 list of all non-joined, non-detached I<threads> objects. In a scalar context,
381 returns a count of the same.
383 With a I<true> argument (using C<threads::running>), returns a list of all
384 non-joined, non-detached I<threads> objects that are still running.
386 With a I<false> argument (using C<threads::joinable>), returns a list of all
387 non-joined, non-detached I<threads> objects that have finished running (i.e.,
388 for which C<-E<gt>join()> will not I<block>).
390 =item $thr1->equal($thr2)
392 Tests if two threads objects are the same thread or not. This is overloaded
393 to the more natural forms:
395 if ($thr1 == $thr2) {
396 print("Threads are the same\n");
399 if ($thr1 != $thr2) {
400 print("Threads differ\n");
403 (Thread comparison is based on thread IDs.)
407 C<async> creates a thread to execute the block immediately following
408 it. This block is treated as an anonymous subroutine, and so must have a
409 semi-colon after the closing brace. Like C<threads->create()>, C<async>
410 returns a I<threads> object.
414 Threads are executed in an C<eval> context. This method will return C<undef>
415 if the thread terminates I<normally>. Otherwise, it returns the value of
416 C<$@> associated with the thread's execution status in its C<eval> context.
418 =item $thr->_handle()
420 This I<private> method returns the memory location of the internal thread
421 structure associated with a threads object. For Win32, this is a pointer to
422 the C<HANDLE> value returned by C<CreateThread> (i.e., C<HANDLE *>); for other
423 platforms, it is a pointer to the C<pthread_t> structure used in the
424 C<pthread_create> call (i.e., C<pthread_t *>).
426 This method is of no use for general Perl threads programming. Its intent is
427 to provide other (XS-based) thread modules with the capability to access, and
428 possibly manipulate, the underlying thread structure associated with a Perl
431 =item threads->_handle()
433 Class method that allows a thread to obtain its own I<handle>.
437 =head1 EXITING A THREAD
439 The usual method for terminating a thread is to
440 L<return()|perlfunc/"return EXPR"> from the entry point function with the
441 appropriate return value(s).
445 =item threads->exit()
447 If needed, a thread can be exited at any time by calling
448 C<threads-E<gt>exit()>. This will cause the thread to return C<undef> in a
449 scalar context, or the empty list in a list context.
451 When called from the I<main> thread, this behaves the same as C<exit(0)>.
453 =item threads->exit(status)
455 When called from a thread, this behaves like C<threads-E<gt>exit()> (i.e., the
456 exit status code is ignored).
458 When called from the I<main> thread, this behaves the same as C<exit(status)>.
462 Calling C<die()> in a thread indicates an abnormal exit for the thread. Any
463 C<$SIG{__DIE__}> handler in the thread will be called first, and then the
464 thread will exit with a warning message that will contain any arguments passed
465 in the C<die()> call.
469 Calling L<exit()|perlfunc/"exit EXPR"> inside a thread causes the whole
470 application to terminate. Because of this, the use of C<exit()> inside
471 threaded code, or in modules that might be used in threaded applications, is
472 strongly discouraged.
474 If C<exit()> really is needed, then consider using the following:
476 threads->exit() if threads->can('exit'); # Thread friendly
479 =item use threads 'exit' => 'thread_only'
481 This globally overrides the default behavior of calling C<exit()> inside a
482 thread, and effectively causes such calls to behave the same as
483 C<threads-E<gt>exit()>. In other words, with this setting, calling C<exit()>
484 causes only the thread to terminate.
486 Because of its global effect, this setting should not be used inside modules
489 The I<main> thread is unaffected by this setting.
491 =item threads->create({'exit' => 'thread_only'}, ...)
493 This overrides the default behavior of C<exit()> inside the newly created
496 =item $thr->set_thread_exit_only(boolean)
498 This can be used to change the I<exit thread only> behavior for a thread after
499 it has been created. With a I<true> argument, C<exit()> will cause the only
500 the thread to exit. With a I<false> argument, C<exit()> will terminate the
503 The I<main> thread is unaffected by this call.
505 =item threads->set_thread_exit_only(boolean)
507 Class method for use inside a thread to changes its own behavior for
510 The I<main> thread is unaffected by this call.
516 The following boolean methods are useful in determining the I<state> of a
521 =item $thr->is_running()
523 Returns true if a thread is still running (i.e., if its entry point function
524 has not yet finished/exited).
526 =item $thr->is_joinable()
528 Returns true if the thread has finished running, is not detached and has not
529 yet been joined. In other works, the thread is ready to be joined and will
532 =item $thr->is_detached()
534 Returns true if the thread has been detached.
536 =item threads->is_detached()
538 Class method that allows a thread to determine whether or not it is detached.
542 =head1 THREAD CONTEXT
544 As with subroutines, the type of value returned from a thread's entry point
545 function may be determined by the thread's I<context>: list, scalar or void.
546 The thread's context is determined at thread creation. This is necessary so
547 that the context is available to the entry point function via
548 L<wantarray()|perlfunc/"wantarray">. The thread may then specify a value of
549 the appropriate type to be returned from C<-E<gt>join()>.
551 =head2 Explicit context
553 Because thread creation and thread joining may occur in different contexts, it
554 may be desirable to state the context explicitly to the thread's entry point
555 function. This may be done by calling C<-E<gt>create()> with a parameter hash
556 as the first argument:
558 my $thr = threads->create({'context' => 'list'}, \&foo);
560 my @results = $thr->join();
562 In the above, the threads object is returned to the parent thread in scalar
563 context, and the thread's entry point function C<foo> will be called in list
564 context such that the parent thread can receive a list from the C<-E<gt>join()>
565 call. Similarly, if you need the threads object, but your thread will not be
566 returning a value (i.e., I<void> context), you would do the following:
568 my $thr = threads->create({'context' => 'void'}, \&foo);
572 The context type may also be used as the I<key> in the parameter hash followed
575 threads->create({'scalar' => 1}, \&foo);
577 my ($thr) = threads->list();
578 my $result = $thr->join();
580 =head2 Implicit context
582 If not explicitly stated, the thread's context is implied from the context
583 of the C<-E<gt>create()> call:
585 # Create thread in list context
586 my ($thr) = threads->create(...);
588 # Create thread in scalar context
589 my $thr = threads->create(...);
591 # Create thread in void context
592 threads->create(...);
594 =head2 $thr->wantarray()
596 This returns the thread's context in the same manner as
597 L<wantarray()|perlfunc/"wantarray">.
599 =head2 threads->wantarray()
601 Class method to return the current thread's context. This is the same as
602 running L<wantarray()|perlfunc/"wantarray"> in the current thread.
604 =head1 THREAD STACK SIZE
606 The default per-thread stack size for different platforms varies
607 significantly, and is almost always far more than is needed for most
608 applications. On Win32, Perl's makefile explicitly sets the default stack to
609 16 MB; on most other platforms, the system default is used, which again may be
610 much larger than is needed.
612 By tuning the stack size to more accurately reflect your application's needs,
613 you may significantly reduce your application's memory usage, and increase the
614 number of simultaneously running threads.
616 N.B., on Windows, Address space allocation granularity is 64 KB, therefore,
617 setting the stack smaller than that on Win32 Perl will not save any more
622 =item threads->get_stack_size();
624 Returns the current default per-thread stack size. The default is zero, which
625 means the system default stack size is currently in use.
627 =item $size = $thr->get_stack_size();
629 Returns the stack size for a particular thread. A return value of zero
630 indicates the system default stack size was used for the thread.
632 =item $old_size = threads->set_stack_size($new_size);
634 Sets a new default per-thread stack size, and returns the previous setting.
636 Some platforms have a minimum thread stack size. Trying to set the stack size
637 below this value will result in a warning, and the minimum stack size will be
640 Some Linux platforms have a maximum stack size. Setting too large of a stack
641 size will cause thread creation to fail.
643 If needed, C<$new_size> will be rounded up to the next multiple of the memory
644 page size (usually 4096 or 8192).
646 Threads created after the stack size is set will then either call
647 C<pthread_attr_setstacksize()> I<(for pthreads platforms)>, or supply the
648 stack size to C<CreateThread()> I<(for Win32 Perl)>.
650 (Obviously, this call does not affect any currently extant threads.)
652 =item use threads ('stack_size' => VALUE);
654 This sets the default per-thread stack size at the start of the application.
656 =item $ENV{'PERL5_ITHREADS_STACK_SIZE'}
658 The default per-thread stack size may be set at the start of the application
659 through the use of the environment variable C<PERL5_ITHREADS_STACK_SIZE>:
661 PERL5_ITHREADS_STACK_SIZE=1048576
662 export PERL5_ITHREADS_STACK_SIZE
663 perl -e'use threads; print(threads->get_stack_size(), "\n")'
665 This value overrides any C<stack_size> parameter given to C<use threads>. Its
666 primary purpose is to permit setting the per-thread stack size for legacy
667 threaded applications.
669 =item threads->create({'stack_size' => VALUE}, FUNCTION, ARGS)
671 The stack size an individual threads may also be specified. This may be done
672 by calling C<-E<gt>create()> with a parameter hash as the first argument:
674 my $thr = threads->create({'stack_size' => 32*4096}, \&foo, @args);
676 =item $thr2 = $thr1->create(FUNCTION, ARGS)
678 This creates a new thread (C<$thr2>) that inherits the stack size from an
679 existing thread (C<$thr1>). This is shorthand for the following:
681 my $stack_size = $thr1->get_stack_size();
682 my $thr2 = threads->create({'stack_size' => $stack_size}, FUNCTION, ARGS);
686 =head1 THREAD SIGNALLING
688 When safe signals is in effect (the default behavior - see L</"Unsafe signals">
689 for more details), then signals may be sent and acted upon by individual
694 =item $thr->kill('SIG...');
696 Sends the specified signal to the thread. Signal names and (positive) signal
697 numbers are the same as those supported by
698 L<kill()|perlfunc/"kill SIGNAL, LIST">. For example, 'SIGTERM', 'TERM' and
699 (depending on the OS) 15 are all valid arguments to C<-E<gt>kill()>.
701 Returns the thread object to allow for method chaining:
703 $thr->kill('SIG...')->join();
707 Signal handlers need to be set up in the threads for the signals they are
708 expected to act upon. Here's an example for I<cancelling> a thread:
714 # Thread 'cancellation' signal handler
715 $SIG{'KILL'} = sub { threads->exit(); };
721 my $thr = threads->create('thr_func');
725 # Signal the thread to terminate, and then detach
726 # it so that it will get cleaned up automatically
727 $thr->kill('KILL')->detach();
729 Here's another simplistic example that illustrates the use of thread
730 signalling in conjunction with a semaphore to provide rudimentary I<suspend>
731 and I<resume> capabilities:
734 use Thread::Semaphore;
740 # Thread 'suspend/resume' signal handler
742 $sema->down(); # Thread suspended
743 $sema->up(); # Thread resumes
749 # Create a semaphore and send it to a thread
750 my $sema = Thread::Semaphore->new();
751 my $thr = threads->create('thr_func', $sema);
759 # Allow the thread to continue
762 CAVEAT: The thread signalling capability provided by this module does not
763 actually send signals via the OS. It I<emulates> signals at the Perl-level
764 such that signal handlers are called in the appropriate thread. For example,
765 sending C<$thr-E<gt>kill('STOP')> does not actually suspend a thread (or the
766 whole process), but does cause a C<$SIG{'STOP'}> handler to be called in that
767 thread (as illustrated above).
769 As such, signals that would normally not be appropriate to use in the
770 C<kill()> command (e.g., C<kill('KILL', $$)>) are okay to use with the
771 C<-E<gt>kill()> method (again, as illustrated above).
773 Correspondingly, sending a signal to a thread does not disrupt the operation
774 the thread is currently working on: The signal will be acted upon after the
775 current operation has completed. For instance, if the thread is I<stuck> on
776 an I/O call, sending it a signal will not cause the I/O call to be interrupted
777 such that the signal is acted up immediately.
779 Sending a signal to a terminated thread is ignored.
785 =item Perl exited with active threads:
787 If the program exits without all threads having either been joined or
788 detached, then this warning will be issued.
790 NOTE: If the I<main> thread exits, then this warning cannot be suppressed
791 using C<no warnings 'threads';> as suggested below.
793 =item Thread creation failed: pthread_create returned #
795 See the appropriate I<man> page for C<pthread_create> to determine the actual
796 cause for the failure.
798 =item Thread # terminated abnormally: ...
800 A thread terminated in some manner other than just returning from its entry
801 point function, or by using C<threads-E<gt>exit()>. For example, the thread
802 may have terminated because of a error, or by using C<die>.
804 =item Using minimum thread stack size of #
806 Some platforms have a minimum thread stack size. Trying to set the stack size
807 below this value will result in the above warning, and the stack size will be
810 =item Thread creation failed: pthread_attr_setstacksize(I<SIZE>) returned 22
812 The specified I<SIZE> exceeds the system's maximum stack size. Use a smaller
813 value for the stack size.
817 If needed, thread warnings can be suppressed by using:
819 no warnings 'threads';
821 in the appropriate scope.
827 =item This Perl not built to support threads
829 The particular copy of Perl that you're trying to use was not built using the
830 C<useithreads> configuration option.
832 Having threads support requires all of Perl and all of the XS modules in the
833 Perl installation to be rebuilt; it is not just a question of adding the
834 L<threads> module (i.e., threaded and non-threaded Perls are binary
837 =item Cannot change stack size of an existing thread
839 The stack size of currently extant threads cannot be changed, therefore, the
840 following results in the above error:
842 $thr->set_stack_size($size);
844 =item Cannot signal threads without safe signals
846 Safe signals must be in effect to use the C<-E<gt>kill()> signalling method.
847 See L</"Unsafe signals"> for more details.
849 =item Unrecognized signal name: ...
851 The particular copy of Perl that you're trying to use does not support the
852 specified signal being used in a C<-E<gt>kill()> call.
856 =head1 BUGS AND LIMITATIONS
858 Before you consider posting a bug report, please consult, and possibly post a
859 message to the discussion forum to see if what you've encountered is a known
864 =item Using non-threadsafe modules
866 Unfortunately, you may encounter Perl modules are not I<threadsafe>. For
867 example, they may crash the Perl interpreter during execution, or may dump
868 core on termination. Depending on the module and the requirements of your
869 application, it may be possible to work around such difficulties.
871 If the module will only be used inside a thread, you can try loading the
872 module from inside the thread entry point function using C<require> (and
873 C<import> if needed):
877 require Unsafe::Module
878 # import Unsafe::Module ...;
883 If the module is needed inside the I<main> thread, try modifying your
884 application so that the module is loaded (again using C<require> and
885 C<import>) after any threads are started, and in such a way that no other
886 threads are started afterwards.
888 If the above does not work, or is not adequate for your application, then file
889 a bug report on L<http://rt.cpan.org/Public/> against the problematic module.
891 =item Parent-child threads
893 On some platforms, it might not be possible to destroy I<parent> threads while
894 there are still existing I<child> threads.
896 =item Creating threads inside special blocks
898 Creating threads inside C<BEGIN>, C<CHECK> or C<INIT> blocks should not be
899 relied upon. Depending on the Perl version and the application code, results
900 may range from success, to (apparently harmless) warnings of leaked scalar, or
901 all the way up to crashing of the Perl interpreter.
905 Since Perl 5.8.0, signals have been made safer in Perl by postponing their
906 handling until the interpreter is in a I<safe> state. See
907 L<perl58delta/"Safe Signals"> and L<perlipc/"Deferred Signals (Safe Signals)">
910 Safe signals is the default behavior, and the old, immediate, unsafe
911 signalling behavior is only in effect in the following situations:
915 =item * Perl was been built with C<PERL_OLD_SIGNALS> (see C<perl -V>).
917 =item * The environment variable C<PERL_SIGNALS> is set to C<unsafe> (see L<perlrun/"PERL_SIGNALS">).
919 =item * The module L<Perl::Unsafe::Signals> is used.
923 If unsafe signals is in effect, then signal handling is not thread-safe, and
924 the C<-E<gt>kill()> signalling method cannot be used.
926 =item Returning closures from threads
928 Returning closures from threads should not be relied upon. Depending of the
929 Perl version and the application code, results may range from success, to
930 (apparently harmless) warnings of leaked scalar, or all the way up to crashing
931 of the Perl interpreter.
933 =item Returning objects from threads
935 Returning objects from threads does not work. Depending on the classes
936 involved, you may be able to work around this by returning a serialized
937 version of the object (e.g., using L<Data::Dumper> or L<Storable>), and then
938 reconstituting it in the joining thread.
940 =item Perl Bugs and the CPAN Version of L<threads>
942 Support for threads extents beyond the code in this module (i.e.,
943 F<threads.pm> and F<threads.xs>), and into the Perl iterpreter itself. Older
944 versions of Perl contain bugs that may manifest themselves despite using the
945 latest version of L<threads> from CPAN. There is no workaround for this other
946 than upgrading to the lastest version of Perl.
956 L<threads> Discussion Forum on CPAN:
957 L<http://www.cpanforum.com/dist/threads>
959 Annotated POD for L<threads>:
960 L<http://annocpan.org/~JDHEDDEN/threads-1.58/threads.pm>
962 L<threads::shared>, L<perlthrtut>
964 L<http://www.perl.com/pub/a/2002/06/11/threads.html> and
965 L<http://www.perl.com/pub/a/2002/09/04/threads.html>
967 Perl threads mailing list:
968 L<http://lists.cpan.org/showlist.cgi?name=iThreads>
970 Stack size discussion:
971 L<http://www.perlmonks.org/?node_id=532956>
975 Artur Bergman E<lt>sky AT crucially DOT netE<gt>
977 threads is released under the same license as Perl.
979 CPAN version produced by Jerry D. Hedden <jdhedden AT cpan DOT org>
981 =head1 ACKNOWLEDGEMENTS
983 Richard Soderberg E<lt>perl AT crystalflame DOT netE<gt> -
984 Helping me out tons, trying to find reasons for races and other weird bugs!
986 Simon Cozens E<lt>simon AT brecon DOT co DOT ukE<gt> -
987 Being there to answer zillions of annoying questions
989 Rocco Caputo E<lt>troc AT netrus DOT netE<gt>
991 Vipul Ved Prakash E<lt>mail AT vipul DOT netE<gt> -
992 Helping with debugging
994 Dean Arnold E<lt>darnold AT presicient DOT comE<gt> -