1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | Coro - real threads in perl |
3 | Coro - the only real threads in perl |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
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29 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
30 | |
30 | |
31 | For a tutorial-style introduction, please read the L<Coro::Intro> |
31 | For a tutorial-style introduction, please read the L<Coro::Intro> |
32 | manpage. This manpage mainly contains reference information. |
32 | manpage. This manpage mainly contains reference information. |
33 | |
33 | |
34 | This module collection manages coroutines, that is, cooperative |
34 | This module collection manages continuations in general, most often |
35 | threads. Coroutines are similar to kernel threads but don't (in general) |
35 | in the form of cooperative threads (also called coroutines in the |
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36 | documentation). They are similar to kernel threads but don't (in general) |
36 | run in parallel at the same time even on SMP machines. The specific flavor |
37 | run in parallel at the same time even on SMP machines. The specific flavor |
37 | of coroutine used in this module also guarantees you that it will not |
38 | of thread offered by this module also guarantees you that it will not |
38 | switch between coroutines unless necessary, at easily-identified points |
39 | switch between threads unless necessary, at easily-identified points in |
39 | in your program, so locking and parallel access are rarely an issue, |
40 | your program, so locking and parallel access are rarely an issue, making |
40 | making coroutine programming much safer and easier than using other thread |
41 | thread programming much safer and easier than using other thread models. |
41 | models. |
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42 | |
42 | |
43 | Unlike the so-called "Perl threads" (which are not actually real threads |
43 | Unlike the so-called "Perl threads" (which are not actually real threads |
44 | but only the windows process emulation ported to unix), Coro provides a |
44 | but only the windows process emulation ported to unix), Coro provides a |
45 | full shared address space, which makes communication between coroutines |
45 | full shared address space, which makes communication between threads |
46 | very easy. And coroutines are fast, too: disabling the Windows process |
46 | very easy. And threads are fast, too: disabling the Windows process |
47 | emulation code in your perl and using Coro can easily result in a two to |
47 | emulation code in your perl and using Coro can easily result in a two to |
48 | four times speed increase for your programs. |
48 | four times speed increase for your programs. |
49 | |
49 | |
50 | Coro achieves that by supporting multiple running interpreters that share |
50 | Coro achieves that by supporting multiple running interpreters that share |
51 | data, which is especially useful to code pseudo-parallel processes and |
51 | data, which is especially useful to code pseudo-parallel processes and |
52 | for event-based programming, such as multiple HTTP-GET requests running |
52 | for event-based programming, such as multiple HTTP-GET requests running |
53 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
53 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
54 | into an event-based environment. |
54 | into an event-based environment. |
55 | |
55 | |
56 | In this module, a coroutines is defined as "callchain + lexical variables |
56 | In this module, a thread is defined as "callchain + lexical variables + |
57 | + @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own |
57 | @_ + $_ + $@ + $/ + C stack), that is, a thread has its own callchain, |
58 | callchain, its own set of lexicals and its own set of perls most important |
58 | its own set of lexicals and its own set of perls most important global |
59 | global variables (see L<Coro::State> for more configuration and background |
59 | variables (see L<Coro::State> for more configuration and background info). |
60 | info). |
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61 | |
60 | |
62 | See also the C<SEE ALSO> section at the end of this document - the Coro |
61 | See also the C<SEE ALSO> section at the end of this document - the Coro |
63 | module family is quite large. |
62 | module family is quite large. |
64 | |
63 | |
65 | =cut |
64 | =cut |
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75 | |
74 | |
76 | our $idle; # idle handler |
75 | our $idle; # idle handler |
77 | our $main; # main coroutine |
76 | our $main; # main coroutine |
78 | our $current; # current coroutine |
77 | our $current; # current coroutine |
79 | |
78 | |
80 | our $VERSION = "5.0"; |
79 | our $VERSION = 5.12; |
81 | |
80 | |
82 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
81 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
83 | our %EXPORT_TAGS = ( |
82 | our %EXPORT_TAGS = ( |
84 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
83 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
85 | ); |
84 | ); |
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115 | sub current() { $current } # [DEPRECATED] |
114 | sub current() { $current } # [DEPRECATED] |
116 | |
115 | |
117 | =item $Coro::idle |
116 | =item $Coro::idle |
118 | |
117 | |
119 | This variable is mainly useful to integrate Coro into event loops. It is |
118 | This variable is mainly useful to integrate Coro into event loops. It is |
120 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
119 | usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is |
121 | pretty low-level functionality. |
120 | pretty low-level functionality. |
122 | |
121 | |
123 | This variable stores a callback that is called whenever the scheduler |
122 | This variable stores either a coroutine or a callback. |
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123 | |
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124 | If it is a callback, the it is called whenever the scheduler finds no |
124 | finds no ready coroutines to run. The default implementation prints |
125 | ready coroutines to run. The default implementation prints "FATAL: |
125 | "FATAL: deadlock detected" and exits, because the program has no other way |
126 | deadlock detected" and exits, because the program has no other way to |
126 | to continue. |
127 | continue. |
127 | |
128 | |
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129 | If it is a coroutine object, then this object will be readied (without |
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130 | invoking any ready hooks, however) when the scheduler finds no other ready |
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131 | coroutines to run. |
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132 | |
128 | This hook is overwritten by modules such as C<Coro::Timer> and |
133 | This hook is overwritten by modules such as C<Coro::EV> and |
129 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
134 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
130 | coroutine so the scheduler can run it. |
135 | coroutine so the scheduler can run it. |
131 | |
136 | |
132 | Note that the callback I<must not>, under any circumstances, block |
137 | Note that the callback I<must not>, under any circumstances, block |
133 | the current coroutine. Normally, this is achieved by having an "idle |
138 | the current coroutine. Normally, this is achieved by having an "idle |
134 | coroutine" that calls the event loop and then blocks again, and then |
139 | coroutine" that calls the event loop and then blocks again, and then |
135 | readying that coroutine in the idle handler. |
140 | readying that coroutine in the idle handler, or by simply placing the idle |
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141 | coroutine in this variable. |
136 | |
142 | |
137 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
143 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
138 | technique. |
144 | technique. |
139 | |
145 | |
140 | Please note that if your callback recursively invokes perl (e.g. for event |
146 | Please note that if your callback recursively invokes perl (e.g. for event |
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169 | |
175 | |
170 | =over 4 |
176 | =over 4 |
171 | |
177 | |
172 | =item async { ... } [@args...] |
178 | =item async { ... } [@args...] |
173 | |
179 | |
174 | Create a new coroutine and return it's coroutine object (usually |
180 | Create a new coroutine and return its coroutine object (usually |
175 | unused). The coroutine will be put into the ready queue, so |
181 | unused). The coroutine will be put into the ready queue, so |
176 | it will start running automatically on the next scheduler run. |
182 | it will start running automatically on the next scheduler run. |
177 | |
183 | |
178 | The first argument is a codeblock/closure that should be executed in the |
184 | The first argument is a codeblock/closure that should be executed in the |
179 | coroutine. When it returns argument returns the coroutine is automatically |
185 | coroutine. When it returns argument returns the coroutine is automatically |
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346 | See C<async> and C<Coro::State::new> for additional info about the |
352 | See C<async> and C<Coro::State::new> for additional info about the |
347 | coroutine environment. |
353 | coroutine environment. |
348 | |
354 | |
349 | =cut |
355 | =cut |
350 | |
356 | |
351 | sub _terminate { |
357 | sub _coro_run { |
352 | terminate &{+shift}; |
358 | terminate &{+shift}; |
353 | } |
359 | } |
354 | |
360 | |
355 | =item $success = $coroutine->ready |
361 | =item $success = $coroutine->ready |
356 | |
362 | |
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531 | would cause a deadlock unless there is an idle handler that wakes up some |
537 | would cause a deadlock unless there is an idle handler that wakes up some |
532 | coroutines. |
538 | coroutines. |
533 | |
539 | |
534 | =item my $guard = Coro::guard { ... } |
540 | =item my $guard = Coro::guard { ... } |
535 | |
541 | |
536 | This creates and returns a guard object. Nothing happens until the object |
542 | This function still exists, but is deprecated. Please use the |
537 | gets destroyed, in which case the codeblock given as argument will be |
543 | C<Guard::guard> function instead. |
538 | executed. This is useful to free locks or other resources in case of a |
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539 | runtime error or when the coroutine gets canceled, as in both cases the |
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540 | guard block will be executed. The guard object supports only one method, |
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541 | C<< ->cancel >>, which will keep the codeblock from being executed. |
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542 | |
544 | |
543 | Example: set some flag and clear it again when the coroutine gets canceled |
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544 | or the function returns: |
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545 | |
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546 | sub do_something { |
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547 | my $guard = Coro::guard { $busy = 0 }; |
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548 | $busy = 1; |
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549 | |
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550 | # do something that requires $busy to be true |
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551 | } |
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552 | |
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553 | =cut |
545 | =cut |
554 | |
546 | |
555 | sub guard(&) { |
547 | BEGIN { *guard = \&Guard::guard } |
556 | bless \(my $cb = $_[0]), "Coro::guard" |
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557 | } |
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558 | |
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559 | sub Coro::guard::cancel { |
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560 | ${$_[0]} = sub { }; |
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561 | } |
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562 | |
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563 | sub Coro::guard::DESTROY { |
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564 | ${$_[0]}->(); |
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565 | } |
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566 | |
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567 | |
548 | |
568 | =item unblock_sub { ... } |
549 | =item unblock_sub { ... } |
569 | |
550 | |
570 | This utility function takes a BLOCK or code reference and "unblocks" it, |
551 | This utility function takes a BLOCK or code reference and "unblocks" it, |
571 | returning a new coderef. Unblocking means that calling the new coderef |
552 | returning a new coderef. Unblocking means that calling the new coderef |
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573 | original code ref will be called (with parameters) from within another |
554 | original code ref will be called (with parameters) from within another |
574 | coroutine. |
555 | coroutine. |
575 | |
556 | |
576 | The reason this function exists is that many event libraries (such as the |
557 | The reason this function exists is that many event libraries (such as the |
577 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
558 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
578 | of thread-safety). This means you must not block within event callbacks, |
559 | of reentrancy). This means you must not block within event callbacks, |
579 | otherwise you might suffer from crashes or worse. The only event library |
560 | otherwise you might suffer from crashes or worse. The only event library |
580 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
561 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
581 | |
562 | |
582 | This function allows your callbacks to block by executing them in another |
563 | This function allows your callbacks to block by executing them in another |
583 | coroutine where it is safe to block. One example where blocking is handy |
564 | coroutine where it is safe to block. One example where blocking is handy |
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629 | } |
610 | } |
630 | } |
611 | } |
631 | |
612 | |
632 | =item $cb = Coro::rouse_cb |
613 | =item $cb = Coro::rouse_cb |
633 | |
614 | |
634 | Create and return a "rouse callback". That's a code reference that, when |
615 | Create and return a "rouse callback". That's a code reference that, |
635 | called, will save its arguments and notify the owner coroutine of the |
616 | when called, will remember a copy of its arguments and notify the owner |
636 | callback. |
617 | coroutine of the callback. |
637 | |
618 | |
638 | See the next function. |
619 | See the next function. |
639 | |
620 | |
640 | =item @args = Coro::rouse_wait [$cb] |
621 | =item @args = Coro::rouse_wait [$cb] |
641 | |
622 | |
642 | Wait for the specified rouse callback (or the last one tht was created in |
623 | Wait for the specified rouse callback (or the last one that was created in |
643 | this coroutine). |
624 | this coroutine). |
644 | |
625 | |
645 | As soon as the callback is invoked (or when the calback was invoked before |
626 | As soon as the callback is invoked (or when the callback was invoked |
646 | C<rouse_wait>), it will return a copy of the arguments originally passed |
627 | before C<rouse_wait>), it will return the arguments originally passed to |
647 | to the rouse callback. |
628 | the rouse callback. |
648 | |
629 | |
649 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
630 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
650 | |
631 | |
651 | =back |
632 | =back |
652 | |
633 | |
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675 | |
656 | |
676 | Coro offers two functions specifically designed to make this easy, |
657 | Coro offers two functions specifically designed to make this easy, |
677 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
658 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
678 | |
659 | |
679 | The first function, C<rouse_cb>, generates and returns a callback that, |
660 | The first function, C<rouse_cb>, generates and returns a callback that, |
680 | when invoked, will save it's arguments and notify the coroutine that |
661 | when invoked, will save its arguments and notify the coroutine that |
681 | created the callback. |
662 | created the callback. |
682 | |
663 | |
683 | The second function, C<rouse_wait>, waits for the callback to be called |
664 | The second function, C<rouse_wait>, waits for the callback to be called |
684 | (by calling C<schedule> to go to sleep) and returns the arguments |
665 | (by calling C<schedule> to go to sleep) and returns the arguments |
685 | originally passed to the callback. |
666 | originally passed to the callback. |
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732 | fix your libc and use a saner backend. |
713 | fix your libc and use a saner backend. |
733 | |
714 | |
734 | =item perl process emulation ("threads") |
715 | =item perl process emulation ("threads") |
735 | |
716 | |
736 | This module is not perl-pseudo-thread-safe. You should only ever use this |
717 | This module is not perl-pseudo-thread-safe. You should only ever use this |
737 | module from the same thread (this requirement might be removed in the |
718 | module from the first thread (this requirement might be removed in the |
738 | future to allow per-thread schedulers, but Coro::State does not yet allow |
719 | future to allow per-thread schedulers, but Coro::State does not yet allow |
739 | this). I recommend disabling thread support and using processes, as having |
720 | this). I recommend disabling thread support and using processes, as having |
740 | the windows process emulation enabled under unix roughly halves perl |
721 | the windows process emulation enabled under unix roughly halves perl |
741 | performance, even when not used. |
722 | performance, even when not used. |
742 | |
723 | |
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759 | |
740 | |
760 | Debugging: L<Coro::Debug>. |
741 | Debugging: L<Coro::Debug>. |
761 | |
742 | |
762 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
743 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
763 | |
744 | |
764 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
745 | Locking and IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
765 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
746 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
766 | |
747 | |
767 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
748 | I/O and Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
768 | |
749 | |
769 | Compatibility: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
750 | Compatibility with other modules: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
770 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
751 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
771 | L<Coro::Select>. |
752 | L<Coro::Select>. |
772 | |
753 | |
773 | XS API: L<Coro::MakeMaker>. |
754 | XS API: L<Coro::MakeMaker>. |
774 | |
755 | |
775 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
756 | Low level Configuration, Thread Environment, Continuations: L<Coro::State>. |
776 | |
757 | |
777 | =head1 AUTHOR |
758 | =head1 AUTHOR |
778 | |
759 | |
779 | Marc Lehmann <schmorp@schmorp.de> |
760 | Marc Lehmann <schmorp@schmorp.de> |
780 | http://home.schmorp.de/ |
761 | http://home.schmorp.de/ |