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 1.61
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 != $thr2) {
400 print("Threads differ\n");
403 (Thread comparison is based on thread IDs.)
407 C<async> creates a thread to execute the block immediately following
408 it. This block is treated as an anonymous subroutine, and so must have a
409 semicolon after the closing brace. Like C<threads-E<gt>create()>, C<async>
410 returns a I<threads> object.
414 Threads are executed in an C<eval> context. This method will return C<undef>
415 if the thread terminates I<normally>. Otherwise, it returns the value of
416 C<$@> 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' => 'threads_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 only the
500 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 change its own behavior for C<exit()>.
509 The I<main> thread is unaffected by this call.
515 The following boolean methods are useful in determining the I<state> of a
520 =item $thr->is_running()
522 Returns true if a thread is still running (i.e., if its entry point function
523 has not yet finished or exited).
525 =item $thr->is_joinable()
527 Returns true if the thread has finished running, is not detached and has not
528 yet been joined. In other words, the thread is ready to be joined, and a call
529 to C<$thr-E<gt>join()> will not I<block>.
531 =item $thr->is_detached()
533 Returns true if the thread has been detached.
535 =item threads->is_detached()
537 Class method that allows a thread to determine whether or not it is detached.
541 =head1 THREAD CONTEXT
543 As with subroutines, the type of value returned from a thread's entry point
544 function may be determined by the thread's I<context>: list, scalar or void.
545 The thread's context is determined at thread creation. This is necessary so
546 that the context is available to the entry point function via
547 L<wantarray()|perlfunc/"wantarray">. The thread may then specify a value of
548 the appropriate type to be returned from C<-E<gt>join()>.
550 =head2 Explicit context
552 Because thread creation and thread joining may occur in different contexts, it
553 may be desirable to state the context explicitly to the thread's entry point
554 function. This may be done by calling C<-E<gt>create()> with a hash reference
555 as the first argument:
557 my $thr = threads->create({'context' => 'list'}, \&foo);
559 my @results = $thr->join();
561 In the above, the threads object is returned to the parent thread in scalar
562 context, and the thread's entry point function C<foo> will be called in list
563 (array) context such that the parent thread can receive a list (array) from
564 the C<-E<gt>join()> call. (C<'array'> is synonymous with C<'list'>.)
566 Similarly, if you need the threads object, but your thread will not be
567 returning a value (i.e., I<void> context), you would do the following:
569 my $thr = threads->create({'context' => 'void'}, \&foo);
573 The context type may also be used as the I<key> in the hash reference followed
576 threads->create({'scalar' => 1}, \&foo);
578 my ($thr) = threads->list();
579 my $result = $thr->join();
581 =head2 Implicit context
583 If not explicitly stated, the thread's context is implied from the context
584 of the C<-E<gt>create()> call:
586 # Create thread in list context
587 my ($thr) = threads->create(...);
589 # Create thread in scalar context
590 my $thr = threads->create(...);
592 # Create thread in void context
593 threads->create(...);
595 =head2 $thr->wantarray()
597 This returns the thread's context in the same manner as
598 L<wantarray()|perlfunc/"wantarray">.
600 =head2 threads->wantarray()
602 Class method to return the current thread's context. This returns the same
603 value as running L<wantarray()|perlfunc/"wantarray"> inside the current
604 thread's entry point function.
606 =head1 THREAD STACK SIZE
608 The default per-thread stack size for different platforms varies
609 significantly, and is almost always far more than is needed for most
610 applications. On Win32, Perl's makefile explicitly sets the default stack to
611 16 MB; on most other platforms, the system default is used, which again may be
612 much larger than is needed.
614 By tuning the stack size to more accurately reflect your application's needs,
615 you may significantly reduce your application's memory usage, and increase the
616 number of simultaneously running threads.
618 Note that on Windows, address space allocation granularity is 64 KB,
619 therefore, setting the stack smaller than that on Win32 Perl will not save any
624 =item threads->get_stack_size();
626 Returns the current default per-thread stack size. The default is zero, which
627 means the system default stack size is currently in use.
629 =item $size = $thr->get_stack_size();
631 Returns the stack size for a particular thread. A return value of zero
632 indicates the system default stack size was used for the thread.
634 =item $old_size = threads->set_stack_size($new_size);
636 Sets a new default per-thread stack size, and returns the previous setting.
638 Some platforms have a minimum thread stack size. Trying to set the stack size
639 below this value will result in a warning, and the minimum stack size will be
642 Some Linux platforms have a maximum stack size. Setting too large of a stack
643 size will cause thread creation to fail.
645 If needed, C<$new_size> will be rounded up to the next multiple of the memory
646 page size (usually 4096 or 8192).
648 Threads created after the stack size is set will then either call
649 C<pthread_attr_setstacksize()> I<(for pthreads platforms)>, or supply the
650 stack size to C<CreateThread()> I<(for Win32 Perl)>.
652 (Obviously, this call does not affect any currently extant threads.)
654 =item use threads ('stack_size' => VALUE);
656 This sets the default per-thread stack size at the start of the application.
658 =item $ENV{'PERL5_ITHREADS_STACK_SIZE'}
660 The default per-thread stack size may be set at the start of the application
661 through the use of the environment variable C<PERL5_ITHREADS_STACK_SIZE>:
663 PERL5_ITHREADS_STACK_SIZE=1048576
664 export PERL5_ITHREADS_STACK_SIZE
665 perl -e'use threads; print(threads->get_stack_size(), "\n")'
667 This value overrides any C<stack_size> parameter given to C<use threads>. Its
668 primary purpose is to permit setting the per-thread stack size for legacy
669 threaded applications.
671 =item threads->create({'stack_size' => VALUE}, FUNCTION, ARGS)
673 To specify a particular stack size for any individual thread, call
674 C<-E<gt>create()> with a hash reference as the first argument:
676 my $thr = threads->create({'stack_size' => 32*4096}, \&foo, @args);
678 =item $thr2 = $thr1->create(FUNCTION, ARGS)
680 This creates a new thread (C<$thr2>) that inherits the stack size from an
681 existing thread (C<$thr1>). This is shorthand for the following:
683 my $stack_size = $thr1->get_stack_size();
684 my $thr2 = threads->create({'stack_size' => $stack_size}, FUNCTION, ARGS);
688 =head1 THREAD SIGNALLING
690 When safe signals is in effect (the default behavior - see L</"Unsafe signals">
691 for more details), then signals may be sent and acted upon by individual
696 =item $thr->kill('SIG...');
698 Sends the specified signal to the thread. Signal names and (positive) signal
699 numbers are the same as those supported by
700 L<kill()|perlfunc/"kill SIGNAL, LIST">. For example, 'SIGTERM', 'TERM' and
701 (depending on the OS) 15 are all valid arguments to C<-E<gt>kill()>.
703 Returns the thread object to allow for method chaining:
705 $thr->kill('SIG...')->join();
709 Signal handlers need to be set up in the threads for the signals they are
710 expected to act upon. Here's an example for I<cancelling> a thread:
716 # Thread 'cancellation' signal handler
717 $SIG{'KILL'} = sub { threads->exit(); };
723 my $thr = threads->create('thr_func');
727 # Signal the thread to terminate, and then detach
728 # it so that it will get cleaned up automatically
729 $thr->kill('KILL')->detach();
731 Here's another simplistic example that illustrates the use of thread
732 signalling in conjunction with a semaphore to provide rudimentary I<suspend>
733 and I<resume> capabilities:
736 use Thread::Semaphore;
742 # Thread 'suspend/resume' signal handler
744 $sema->down(); # Thread suspended
745 $sema->up(); # Thread resumes
751 # Create a semaphore and pass it to a thread
752 my $sema = Thread::Semaphore->new();
753 my $thr = threads->create('thr_func', $sema);
761 # Allow the thread to continue
764 CAVEAT: The thread signalling capability provided by this module does not
765 actually send signals via the OS. It I<emulates> signals at the Perl-level
766 such that signal handlers are called in the appropriate thread. For example,
767 sending C<$thr-E<gt>kill('STOP')> does not actually suspend a thread (or the
768 whole process), but does cause a C<$SIG{'STOP'}> handler to be called in that
769 thread (as illustrated above).
771 As such, signals that would normally not be appropriate to use in the
772 C<kill()> command (e.g., C<kill('KILL', $$)>) are okay to use with the
773 C<-E<gt>kill()> method (again, as illustrated above).
775 Correspondingly, sending a signal to a thread does not disrupt the operation
776 the thread is currently working on: The signal will be acted upon after the
777 current operation has completed. For instance, if the thread is I<stuck> on
778 an I/O call, sending it a signal will not cause the I/O call to be interrupted
779 such that the signal is acted up immediately.
781 Sending a signal to a terminated thread is ignored.
787 =item Perl exited with active threads:
789 If the program exits without all threads having either been joined or
790 detached, then this warning will be issued.
792 NOTE: If the I<main> thread exits, then this warning cannot be suppressed
793 using C<no warnings 'threads';> as suggested below.
795 =item Thread creation failed: pthread_create returned #
797 See the appropriate I<man> page for C<pthread_create> to determine the actual
798 cause for the failure.
800 =item Thread # terminated abnormally: ...
802 A thread terminated in some manner other than just returning from its entry
803 point function, or by using C<threads-E<gt>exit()>. For example, the thread
804 may have terminated because of an error, or by using C<die>.
806 =item Using minimum thread stack size of #
808 Some platforms have a minimum thread stack size. Trying to set the stack size
809 below this value will result in the above warning, and the stack size will be
812 =item Thread creation failed: pthread_attr_setstacksize(I<SIZE>) returned 22
814 The specified I<SIZE> exceeds the system's maximum stack size. Use a smaller
815 value for the stack size.
819 If needed, thread warnings can be suppressed by using:
821 no warnings 'threads';
823 in the appropriate scope.
829 =item This Perl not built to support threads
831 The particular copy of Perl that you're trying to use was not built using the
832 C<useithreads> configuration option.
834 Having threads support requires all of Perl and all of the XS modules in the
835 Perl installation to be rebuilt; it is not just a question of adding the
836 L<threads> module (i.e., threaded and non-threaded Perls are binary
839 =item Cannot change stack size of an existing thread
841 The stack size of currently extant threads cannot be changed, therefore, the
842 following results in the above error:
844 $thr->set_stack_size($size);
846 =item Cannot signal threads without safe signals
848 Safe signals must be in effect to use the C<-E<gt>kill()> signalling method.
849 See L</"Unsafe signals"> for more details.
851 =item Unrecognized signal name: ...
853 The particular copy of Perl that you're trying to use does not support the
854 specified signal being used in a C<-E<gt>kill()> call.
858 =head1 BUGS AND LIMITATIONS
860 Before you consider posting a bug report, please consult, and possibly post a
861 message to the discussion forum to see if what you've encountered is a known
866 =item Using non-threadsafe modules
868 Unfortunately, you may encounter Perl modules that are not I<threadsafe>. For
869 example, they may crash the Perl interpreter during execution, or may dump
870 core on termination. Depending on the module and the requirements of your
871 application, it may be possible to work around such difficulties.
873 If the module will only be used inside a thread, you can try loading the
874 module from inside the thread entry point function using C<require> (and
875 C<import> if needed):
879 require Unsafe::Module
880 # import Unsafe::Module ...;
885 If the module is needed inside the I<main> thread, try modifying your
886 application so that the module is loaded (again using C<require> and
887 C<import>) after any threads are started, and in such a way that no other
888 threads are started afterwards.
890 If the above does not work, or is not adequate for your application, then file
891 a bug report on L<http://rt.cpan.org/Public/> against the problematic module.
893 =item Parent-child threads
895 On some platforms, it might not be possible to destroy I<parent> threads while
896 there are still existing I<child> threads.
898 =item Creating threads inside special blocks
900 Creating threads inside C<BEGIN>, C<CHECK> or C<INIT> blocks should not be
901 relied upon. Depending on the Perl version and the application code, results
902 may range from success, to (apparently harmless) warnings of leaked scalar, or
903 all the way up to crashing of the Perl interpreter.
907 Since Perl 5.8.0, signals have been made safer in Perl by postponing their
908 handling until the interpreter is in a I<safe> state. See
909 L<perl58delta/"Safe Signals"> and L<perlipc/"Deferred Signals (Safe Signals)">
912 Safe signals is the default behavior, and the old, immediate, unsafe
913 signalling behavior is only in effect in the following situations:
917 =item * Perl has been built with C<PERL_OLD_SIGNALS> (see C<perl -V>).
919 =item * The environment variable C<PERL_SIGNALS> is set to C<unsafe> (see L<perlrun/"PERL_SIGNALS">).
921 =item * The module L<Perl::Unsafe::Signals> is used.
925 If unsafe signals is in effect, then signal handling is not thread-safe, and
926 the C<-E<gt>kill()> signalling method cannot be used.
928 =item Returning closures from threads
930 Returning closures from threads should not be relied upon. Depending of the
931 Perl version and the application code, results may range from success, to
932 (apparently harmless) warnings of leaked scalar, or all the way up to crashing
933 of the Perl interpreter.
935 =item Returning objects from threads
937 Returning objects from threads does not work. Depending on the classes
938 involved, you may be able to work around this by returning a serialized
939 version of the object (e.g., using L<Data::Dumper> or L<Storable>), and then
940 reconstituting it in the joining thread.
942 =item Perl Bugs and the CPAN Version of L<threads>
944 Support for threads extends beyond the code in this module (i.e.,
945 F<threads.pm> and F<threads.xs>), and into the Perl iterpreter itself. Older
946 versions of Perl contain bugs that may manifest themselves despite using the
947 latest version of L<threads> from CPAN. There is no workaround for this other
948 than upgrading to the lastest version of Perl.
958 L<threads> Discussion Forum on CPAN:
959 L<http://www.cpanforum.com/dist/threads>
961 Annotated POD for L<threads>:
962 L<http://annocpan.org/~JDHEDDEN/threads-1.61/threads.pm>
964 L<threads::shared>, L<perlthrtut>
966 L<http://www.perl.com/pub/a/2002/06/11/threads.html> and
967 L<http://www.perl.com/pub/a/2002/09/04/threads.html>
969 Perl threads mailing list:
970 L<http://lists.cpan.org/showlist.cgi?name=iThreads>
972 Stack size discussion:
973 L<http://www.perlmonks.org/?node_id=532956>
977 Artur Bergman E<lt>sky AT crucially DOT netE<gt>
979 threads is released under the same license as Perl.
981 CPAN version produced by Jerry D. Hedden <jdhedden AT cpan DOT org>
983 =head1 ACKNOWLEDGEMENTS
985 Richard Soderberg E<lt>perl AT crystalflame DOT netE<gt> -
986 Helping me out tons, trying to find reasons for races and other weird bugs!
988 Simon Cozens E<lt>simon AT brecon DOT co DOT ukE<gt> -
989 Being there to answer zillions of annoying questions
991 Rocco Caputo E<lt>troc AT netrus DOT netE<gt>
993 Vipul Ved Prakash E<lt>mail AT vipul DOT netE<gt> -
994 Helping with debugging
996 Dean Arnold E<lt>darnold AT presicient DOT comE<gt> -