1 | NAME |
1 | NAME |
2 | AnyEvent - provide framework for multiple event loops |
2 | AnyEvent - the DBI of event loop programming |
3 | |
3 | |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, IO::Async, Qt and POE are |
5 | event loops. |
5 | various supported event loops/environments. |
6 | |
6 | |
7 | SYNOPSIS |
7 | SYNOPSIS |
8 | use AnyEvent; |
8 | use AnyEvent; |
9 | |
9 | |
10 | # file descriptor readable |
10 | # file descriptor readable |
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37 | |
37 | |
38 | INTRODUCTION/TUTORIAL |
38 | INTRODUCTION/TUTORIAL |
39 | This manpage is mainly a reference manual. If you are interested in a |
39 | This manpage is mainly a reference manual. If you are interested in a |
40 | tutorial or some gentle introduction, have a look at the AnyEvent::Intro |
40 | tutorial or some gentle introduction, have a look at the AnyEvent::Intro |
41 | manpage. |
41 | manpage. |
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42 | |
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43 | SUPPORT |
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44 | There is a mailinglist for discussing all things AnyEvent, and an IRC |
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45 | channel, too. |
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46 | |
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47 | See the AnyEvent project page at the Schmorpforge Ta-Sa Software |
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48 | Repository, at <http://anyevent.schmorp.de>, for more info. |
42 | |
49 | |
43 | WHY YOU SHOULD USE THIS MODULE (OR NOT) |
50 | WHY YOU SHOULD USE THIS MODULE (OR NOT) |
44 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
51 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
45 | nowadays. So what is different about AnyEvent? |
52 | nowadays. So what is different about AnyEvent? |
46 | |
53 | |
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350 | invocation, and callback invocation will be synchronous. Synchronous |
357 | invocation, and callback invocation will be synchronous. Synchronous |
351 | means that it might take a while until the signal gets handled by the |
358 | means that it might take a while until the signal gets handled by the |
352 | process, but it is guaranteed not to interrupt any other callbacks. |
359 | process, but it is guaranteed not to interrupt any other callbacks. |
353 | |
360 | |
354 | The main advantage of using these watchers is that you can share a |
361 | The main advantage of using these watchers is that you can share a |
355 | signal between multiple watchers. |
362 | signal between multiple watchers, and AnyEvent will ensure that signals |
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363 | will not interrupt your program at bad times. |
356 | |
364 | |
357 | This watcher might use %SIG, so programs overwriting those signals |
365 | This watcher might use %SIG (depending on the event loop used), so |
358 | directly will likely not work correctly. |
366 | programs overwriting those signals directly will likely not work |
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367 | correctly. |
359 | |
368 | |
360 | Example: exit on SIGINT |
369 | Example: exit on SIGINT |
361 | |
370 | |
362 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
371 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
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372 | |
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373 | Signal Races, Delays and Workarounds |
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374 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
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375 | callbacks to signals in a generic way, which is a pity, as you cannot do |
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376 | race-free signal handling in perl. AnyEvent will try to do it's best, |
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377 | but in some cases, signals will be delayed. The maximum time a signal |
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378 | might be delayed is specified in $AnyEvent::MAX_SIGNAL_LATENCY (default: |
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379 | 10 seconds). This variable can be changed only before the first signal |
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380 | watcher is created, and should be left alone otherwise. Higher values |
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381 | will cause fewer spurious wake-ups, which is better for power and CPU |
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382 | saving. All these problems can be avoided by installing the optional |
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383 | Async::Interrupt module. This will not work with inherently broken event |
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384 | loops such as Event or Event::Lib (and not with POE currently, as POE |
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385 | does it's own workaround with one-second latency). With those, you just |
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386 | have to suffer the delays. |
363 | |
387 | |
364 | CHILD PROCESS WATCHERS |
388 | CHILD PROCESS WATCHERS |
365 | You can also watch on a child process exit and catch its exit status. |
389 | You can also watch on a child process exit and catch its exit status. |
366 | |
390 | |
367 | The child process is specified by the "pid" argument (if set to 0, it |
391 | The child process is specified by the "pid" argument (one some backends, |
368 | watches for any child process exit). The watcher will triggered only |
392 | using 0 watches for any child process exit, on others this will croak). |
369 | when the child process has finished and an exit status is available, not |
393 | The watcher will be triggered only when the child process has finished |
370 | on any trace events (stopped/continued). |
394 | and an exit status is available, not on any trace events |
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395 | (stopped/continued). |
371 | |
396 | |
372 | The callback will be called with the pid and exit status (as returned by |
397 | The callback will be called with the pid and exit status (as returned by |
373 | waitpid), so unlike other watcher types, you *can* rely on child watcher |
398 | waitpid), so unlike other watcher types, you *can* rely on child watcher |
374 | callback arguments. |
399 | callback arguments. |
375 | |
400 | |
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390 | of when you start the watcher. |
415 | of when you start the watcher. |
391 | |
416 | |
392 | This means you cannot create a child watcher as the very first thing in |
417 | This means you cannot create a child watcher as the very first thing in |
393 | an AnyEvent program, you *have* to create at least one watcher before |
418 | an AnyEvent program, you *have* to create at least one watcher before |
394 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
419 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
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420 | |
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421 | As most event loops do not support waiting for child events, they will |
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422 | be emulated by AnyEvent in most cases, in which the latency and race |
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423 | problems mentioned in the description of signal watchers apply. |
395 | |
424 | |
396 | Example: fork a process and wait for it |
425 | Example: fork a process and wait for it |
397 | |
426 | |
398 | my $done = AnyEvent->condvar; |
427 | my $done = AnyEvent->condvar; |
399 | |
428 | |
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448 | CONDITION VARIABLES |
477 | CONDITION VARIABLES |
449 | If you are familiar with some event loops you will know that all of them |
478 | If you are familiar with some event loops you will know that all of them |
450 | require you to run some blocking "loop", "run" or similar function that |
479 | require you to run some blocking "loop", "run" or similar function that |
451 | will actively watch for new events and call your callbacks. |
480 | will actively watch for new events and call your callbacks. |
452 | |
481 | |
453 | AnyEvent is different, it expects somebody else to run the event loop |
482 | AnyEvent is slightly different: it expects somebody else to run the |
454 | and will only block when necessary (usually when told by the user). |
483 | event loop and will only block when necessary (usually when told by the |
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484 | user). |
455 | |
485 | |
456 | The instrument to do that is called a "condition variable", so called |
486 | The instrument to do that is called a "condition variable", so called |
457 | because they represent a condition that must become true. |
487 | because they represent a condition that must become true. |
458 | |
488 | |
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489 | Now is probably a good time to look at the examples further below. |
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490 | |
459 | Condition variables can be created by calling the "AnyEvent->condvar" |
491 | Condition variables can be created by calling the "AnyEvent->condvar" |
460 | method, usually without arguments. The only argument pair allowed is |
492 | method, usually without arguments. The only argument pair allowed is |
461 | |
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462 | "cb", which specifies a callback to be called when the condition |
493 | "cb", which specifies a callback to be called when the condition |
463 | variable becomes true, with the condition variable as the first argument |
494 | variable becomes true, with the condition variable as the first argument |
464 | (but not the results). |
495 | (but not the results). |
465 | |
496 | |
466 | After creation, the condition variable is "false" until it becomes |
497 | After creation, the condition variable is "false" until it becomes |
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471 | Condition variables are similar to callbacks, except that you can |
502 | Condition variables are similar to callbacks, except that you can |
472 | optionally wait for them. They can also be called merge points - points |
503 | optionally wait for them. They can also be called merge points - points |
473 | in time where multiple outstanding events have been processed. And yet |
504 | in time where multiple outstanding events have been processed. And yet |
474 | another way to call them is transactions - each condition variable can |
505 | another way to call them is transactions - each condition variable can |
475 | be used to represent a transaction, which finishes at some point and |
506 | be used to represent a transaction, which finishes at some point and |
476 | delivers a result. |
507 | delivers a result. And yet some people know them as "futures" - a |
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508 | promise to compute/deliver something that you can wait for. |
477 | |
509 | |
478 | Condition variables are very useful to signal that something has |
510 | Condition variables are very useful to signal that something has |
479 | finished, for example, if you write a module that does asynchronous http |
511 | finished, for example, if you write a module that does asynchronous http |
480 | requests, then a condition variable would be the ideal candidate to |
512 | requests, then a condition variable would be the ideal candidate to |
481 | signal the availability of results. The user can either act when the |
513 | signal the availability of results. The user can either act when the |
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515 | after => 1, |
547 | after => 1, |
516 | cb => sub { $result_ready->send }, |
548 | cb => sub { $result_ready->send }, |
517 | ); |
549 | ); |
518 | |
550 | |
519 | # this "blocks" (while handling events) till the callback |
551 | # this "blocks" (while handling events) till the callback |
520 | # calls send |
552 | # calls -<send |
521 | $result_ready->recv; |
553 | $result_ready->recv; |
522 | |
554 | |
523 | Example: wait for a timer, but take advantage of the fact that condition |
555 | Example: wait for a timer, but take advantage of the fact that condition |
524 | variables are also code references. |
556 | variables are also callable directly. |
525 | |
557 | |
526 | my $done = AnyEvent->condvar; |
558 | my $done = AnyEvent->condvar; |
527 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
559 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
528 | $done->recv; |
560 | $done->recv; |
529 | |
561 | |
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535 | |
567 | |
536 | ... |
568 | ... |
537 | |
569 | |
538 | my @info = $couchdb->info->recv; |
570 | my @info = $couchdb->info->recv; |
539 | |
571 | |
540 | And this is how you would just ste a callback to be called whenever the |
572 | And this is how you would just set a callback to be called whenever the |
541 | results are available: |
573 | results are available: |
542 | |
574 | |
543 | $couchdb->info->cb (sub { |
575 | $couchdb->info->cb (sub { |
544 | my @info = $_[0]->recv; |
576 | my @info = $_[0]->recv; |
545 | }); |
577 | }); |
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560 | |
592 | |
561 | Any arguments passed to the "send" call will be returned by all |
593 | Any arguments passed to the "send" call will be returned by all |
562 | future "->recv" calls. |
594 | future "->recv" calls. |
563 | |
595 | |
564 | Condition variables are overloaded so one can call them directly (as |
596 | Condition variables are overloaded so one can call them directly (as |
565 | a code reference). Calling them directly is the same as calling |
597 | if they were a code reference). Calling them directly is the same as |
566 | "send". Note, however, that many C-based event loops do not handle |
598 | calling "send". |
567 | overloading, so as tempting as it may be, passing a condition |
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568 | variable instead of a callback does not work. Both the pure perl and |
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569 | EV loops support overloading, however, as well as all functions that |
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570 | use perl to invoke a callback (as in AnyEvent::Socket and |
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571 | AnyEvent::DNS for example). |
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572 | |
599 | |
573 | $cv->croak ($error) |
600 | $cv->croak ($error) |
574 | Similar to send, but causes all call's to "->recv" to invoke |
601 | Similar to send, but causes all call's to "->recv" to invoke |
575 | "Carp::croak" with the given error message/object/scalar. |
602 | "Carp::croak" with the given error message/object/scalar. |
576 | |
603 | |
577 | This can be used to signal any errors to the condition variable |
604 | This can be used to signal any errors to the condition variable |
578 | user/consumer. |
605 | user/consumer. Doing it this way instead of calling "croak" directly |
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606 | delays the error detetcion, but has the overwhelmign advantage that |
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607 | it diagnoses the error at the place where the result is expected, |
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608 | and not deep in some event clalback without connection to the actual |
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609 | code causing the problem. |
579 | |
610 | |
580 | $cv->begin ([group callback]) |
611 | $cv->begin ([group callback]) |
581 | $cv->end |
612 | $cv->end |
582 | These two methods can be used to combine many transactions/events |
613 | These two methods can be used to combine many transactions/events |
583 | into one. For example, a function that pings many hosts in parallel |
614 | into one. For example, a function that pings many hosts in parallel |
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671 | function will call "croak". |
702 | function will call "croak". |
672 | |
703 | |
673 | In list context, all parameters passed to "send" will be returned, |
704 | In list context, all parameters passed to "send" will be returned, |
674 | in scalar context only the first one will be returned. |
705 | in scalar context only the first one will be returned. |
675 | |
706 | |
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707 | Note that doing a blocking wait in a callback is not supported by |
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708 | any event loop, that is, recursive invocation of a blocking "->recv" |
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709 | is not allowed, and the "recv" call will "croak" if such a condition |
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710 | is detected. This condition can be slightly loosened by using |
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711 | Coro::AnyEvent, which allows you to do a blocking "->recv" from any |
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712 | thread that doesn't run the event loop itself. |
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713 | |
676 | Not all event models support a blocking wait - some die in that case |
714 | Not all event models support a blocking wait - some die in that case |
677 | (programs might want to do that to stay interactive), so *if you are |
715 | (programs might want to do that to stay interactive), so *if you are |
678 | using this from a module, never require a blocking wait*, but let |
716 | using this from a module, never require a blocking wait*. Instead, |
679 | the caller decide whether the call will block or not (for example, |
717 | let the caller decide whether the call will block or not (for |
680 | by coupling condition variables with some kind of request results |
718 | example, by coupling condition variables with some kind of request |
681 | and supporting callbacks so the caller knows that getting the result |
719 | results and supporting callbacks so the caller knows that getting |
682 | will not block, while still supporting blocking waits if the caller |
720 | the result will not block, while still supporting blocking waits if |
683 | so desires). |
721 | the caller so desires). |
684 | |
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685 | Another reason *never* to "->recv" in a module is that you cannot |
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686 | sensibly have two "->recv"'s in parallel, as that would require |
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687 | multiple interpreters or coroutines/threads, none of which |
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688 | "AnyEvent" can supply. |
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689 | |
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690 | The Coro module, however, *can* and *does* supply coroutines and, in |
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691 | fact, Coro::AnyEvent replaces AnyEvent's condvars by coroutine-safe |
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692 | versions and also integrates coroutines into AnyEvent, making |
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693 | blocking "->recv" calls perfectly safe as long as they are done from |
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694 | another coroutine (one that doesn't run the event loop). |
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695 | |
722 | |
696 | You can ensure that "-recv" never blocks by setting a callback and |
723 | You can ensure that "-recv" never blocks by setting a callback and |
697 | only calling "->recv" from within that callback (or at a later |
724 | only calling "->recv" from within that callback (or at a later |
698 | time). This will work even when the event loop does not support |
725 | time). This will work even when the event loop does not support |
699 | blocking waits otherwise. |
726 | blocking waits otherwise. |
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734 | |
761 | |
735 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
762 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
736 | AnyEvent::Impl::Tk based on Tk, very broken. |
763 | AnyEvent::Impl::Tk based on Tk, very broken. |
737 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
764 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
738 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
765 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
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766 | AnyEvent::Impl::Irssi used when running within irssi. |
739 | |
767 | |
740 | Backends with special needs. |
768 | Backends with special needs. |
741 | Qt requires the Qt::Application to be instantiated first, but will |
769 | Qt requires the Qt::Application to be instantiated first, but will |
742 | otherwise be picked up automatically. As long as the main program |
770 | otherwise be picked up automatically. As long as the main program |
743 | instantiates the application before any AnyEvent watchers are |
771 | instantiates the application before any AnyEvent watchers are |
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808 | creates and installs the global IO::AIO watcher in a "post_detect" |
836 | creates and installs the global IO::AIO watcher in a "post_detect" |
809 | block to avoid autodetecting the event module at load time. |
837 | block to avoid autodetecting the event module at load time. |
810 | |
838 | |
811 | If called in scalar or list context, then it creates and returns an |
839 | If called in scalar or list context, then it creates and returns an |
812 | object that automatically removes the callback again when it is |
840 | object that automatically removes the callback again when it is |
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841 | destroyed (or "undef" when the hook was immediately executed). See |
813 | destroyed. See Coro::BDB for a case where this is useful. |
842 | AnyEvent::AIO for a case where this is useful. |
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843 | |
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844 | Example: Create a watcher for the IO::AIO module and store it in |
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845 | $WATCHER. Only do so after the event loop is initialised, though. |
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846 | |
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847 | our WATCHER; |
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848 | |
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849 | my $guard = AnyEvent::post_detect { |
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850 | $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); |
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851 | }; |
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852 | |
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853 | # the ||= is important in case post_detect immediately runs the block, |
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854 | # as to not clobber the newly-created watcher. assigning both watcher and |
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855 | # post_detect guard to the same variable has the advantage of users being |
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856 | # able to just C<undef $WATCHER> if the watcher causes them grief. |
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857 | |
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858 | $WATCHER ||= $guard; |
814 | |
859 | |
815 | @AnyEvent::post_detect |
860 | @AnyEvent::post_detect |
816 | If there are any code references in this array (you can "push" to it |
861 | If there are any code references in this array (you can "push" to it |
817 | before or after loading AnyEvent), then they will called directly |
862 | before or after loading AnyEvent), then they will called directly |
818 | after the event loop has been chosen. |
863 | after the event loop has been chosen. |
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994 | by "PERL_ANYEVENT_MODEL". |
1039 | by "PERL_ANYEVENT_MODEL". |
995 | |
1040 | |
996 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
1041 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
997 | event model it chooses. |
1042 | event model it chooses. |
998 | |
1043 | |
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1044 | When set to 8 or higher, then AnyEvent will report extra information |
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1045 | on which optional modules it loads and how it implements certain |
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1046 | features. |
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1047 | |
999 | "PERL_ANYEVENT_STRICT" |
1048 | "PERL_ANYEVENT_STRICT" |
1000 | AnyEvent does not do much argument checking by default, as thorough |
1049 | AnyEvent does not do much argument checking by default, as thorough |
1001 | argument checking is very costly. Setting this variable to a true |
1050 | argument checking is very costly. Setting this variable to a true |
1002 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1051 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1003 | thoroughly check the arguments passed to most method calls. If it |
1052 | thoroughly check the arguments passed to most method calls. If it |
1004 | finds any problems, it will croak. |
1053 | finds any problems, it will croak. |
1005 | |
1054 | |
1006 | In other words, enables "strict" mode. |
1055 | In other words, enables "strict" mode. |
1007 | |
1056 | |
1008 | Unlike "use strict", it is definitely recommended to keep it off in |
1057 | Unlike "use strict" (or it's modern cousin, "use common::sense", it |
1009 | production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment |
1058 | is definitely recommended to keep it off in production. Keeping |
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1059 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1010 | while developing programs can be very useful, however. |
1060 | programs can be very useful, however. |
1011 | |
1061 | |
1012 | "PERL_ANYEVENT_MODEL" |
1062 | "PERL_ANYEVENT_MODEL" |
1013 | This can be used to specify the event model to be used by AnyEvent, |
1063 | This can be used to specify the event model to be used by AnyEvent, |
1014 | before auto detection and -probing kicks in. It must be a string |
1064 | before auto detection and -probing kicks in. It must be a string |
1015 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
1065 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
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1072 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1122 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1073 | When neither "ca_file" nor "ca_path" was specified during |
1123 | When neither "ca_file" nor "ca_path" was specified during |
1074 | AnyEvent::TLS context creation, and either of these environment |
1124 | AnyEvent::TLS context creation, and either of these environment |
1075 | variables exist, they will be used to specify CA certificate |
1125 | variables exist, they will be used to specify CA certificate |
1076 | locations instead of a system-dependent default. |
1126 | locations instead of a system-dependent default. |
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1127 | |
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1128 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
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1129 | When these are set to 1, then the respective modules are not loaded. |
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1130 | Mostly good for testing AnyEvent itself. |
1077 | |
1131 | |
1078 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1132 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1079 | This is an advanced topic that you do not normally need to use AnyEvent |
1133 | This is an advanced topic that you do not normally need to use AnyEvent |
1080 | in a module. This section is only of use to event loop authors who want |
1134 | in a module. This section is only of use to event loop authors who want |
1081 | to provide AnyEvent compatibility. |
1135 | to provide AnyEvent compatibility. |
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1586 | SIGCHLD |
1640 | SIGCHLD |
1587 | A handler for "SIGCHLD" is installed by AnyEvent's child watcher |
1641 | A handler for "SIGCHLD" is installed by AnyEvent's child watcher |
1588 | emulation for event loops that do not support them natively. Also, |
1642 | emulation for event loops that do not support them natively. Also, |
1589 | some event loops install a similar handler. |
1643 | some event loops install a similar handler. |
1590 | |
1644 | |
1591 | If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent |
1645 | Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, |
1592 | will reset it to default, to avoid losing child exit statuses. |
1646 | then AnyEvent will reset it to default, to avoid losing child exit |
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1647 | statuses. |
1593 | |
1648 | |
1594 | SIGPIPE |
1649 | SIGPIPE |
1595 | A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is |
1650 | A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is |
1596 | "undef" when AnyEvent gets loaded. |
1651 | "undef" when AnyEvent gets loaded. |
1597 | |
1652 | |
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… | |
1605 | it is that this way, the handler will be restored to defaults on |
1660 | it is that this way, the handler will be restored to defaults on |
1606 | exec. |
1661 | exec. |
1607 | |
1662 | |
1608 | Feel free to install your own handler, or reset it to defaults. |
1663 | Feel free to install your own handler, or reset it to defaults. |
1609 | |
1664 | |
|
|
1665 | RECOMMENDED/OPTIONAL MODULES |
|
|
1666 | One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and |
|
|
1667 | it's built-in modules) are required to use it. |
|
|
1668 | |
|
|
1669 | That does not mean that AnyEvent won't take advantage of some additional |
|
|
1670 | modules if they are installed. |
|
|
1671 | |
|
|
1672 | This section epxlains which additional modules will be used, and how |
|
|
1673 | they affect AnyEvent's operetion. |
|
|
1674 | |
|
|
1675 | Async::Interrupt |
|
|
1676 | This slightly arcane module is used to implement fast signal |
|
|
1677 | handling: To my knowledge, there is no way to do completely |
|
|
1678 | race-free and quick signal handling in pure perl. To ensure that |
|
|
1679 | signals still get delivered, AnyEvent will start an interval timer |
|
|
1680 | to wake up perl (and catch the signals) with some delay (default is |
|
|
1681 | 10 seconds, look for $AnyEvent::MAX_SIGNAL_LATENCY). |
|
|
1682 | |
|
|
1683 | If this module is available, then it will be used to implement |
|
|
1684 | signal catching, which means that signals will not be delayed, and |
|
|
1685 | the event loop will not be interrupted regularly, which is more |
|
|
1686 | efficient (And good for battery life on laptops). |
|
|
1687 | |
|
|
1688 | This affects not just the pure-perl event loop, but also other event |
|
|
1689 | loops that have no signal handling on their own (e.g. Glib, Tk, Qt). |
|
|
1690 | |
|
|
1691 | Some event loops (POE, Event, Event::Lib) offer signal watchers |
|
|
1692 | natively, and either employ their own workarounds (POE) or use |
|
|
1693 | AnyEvent's workaround (using $AnyEvent::MAX_SIGNAL_LATENCY). |
|
|
1694 | Installing Async::Interrupt does nothing for those backends. |
|
|
1695 | |
|
|
1696 | EV This module isn't really "optional", as it is simply one of the |
|
|
1697 | backend event loops that AnyEvent can use. However, it is simply the |
|
|
1698 | best event loop available in terms of features, speed and stability: |
|
|
1699 | It supports the AnyEvent API optimally, implements all the watcher |
|
|
1700 | types in XS, does automatic timer adjustments even when no monotonic |
|
|
1701 | clock is available, can take avdantage of advanced kernel interfaces |
|
|
1702 | such as "epoll" and "kqueue", and is the fastest backend *by far*. |
|
|
1703 | You can even embed Glib/Gtk2 in it (or vice versa, see EV::Glib and |
|
|
1704 | Glib::EV). |
|
|
1705 | |
|
|
1706 | Guard |
|
|
1707 | The guard module, when used, will be used to implement |
|
|
1708 | "AnyEvent::Util::guard". This speeds up guards considerably (and |
|
|
1709 | uses a lot less memory), but otherwise doesn't affect guard |
|
|
1710 | operation much. It is purely used for performance. |
|
|
1711 | |
|
|
1712 | JSON and JSON::XS |
|
|
1713 | This module is required when you want to read or write JSON data via |
|
|
1714 | AnyEvent::Handle. It is also written in pure-perl, but can take |
|
|
1715 | advantage of the ultra-high-speed JSON::XS module when it is |
|
|
1716 | installed. |
|
|
1717 | |
|
|
1718 | In fact, AnyEvent::Handle will use JSON::XS by default if it is |
|
|
1719 | installed. |
|
|
1720 | |
|
|
1721 | Net::SSLeay |
|
|
1722 | Implementing TLS/SSL in Perl is certainly interesting, but not very |
|
|
1723 | worthwhile: If this module is installed, then AnyEvent::Handle (with |
|
|
1724 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
|
|
1725 | |
|
|
1726 | Time::HiRes |
|
|
1727 | This module is part of perl since release 5.008. It will be used |
|
|
1728 | when the chosen event library does not come with a timing source on |
|
|
1729 | it's own. The pure-perl event loop (AnyEvent::Impl::Perl) will |
|
|
1730 | additionally use it to try to use a monotonic clock for timing |
|
|
1731 | stability. |
|
|
1732 | |
1610 | FORK |
1733 | FORK |
1611 | Most event libraries are not fork-safe. The ones who are usually are |
1734 | Most event libraries are not fork-safe. The ones who are usually are |
1612 | because they rely on inefficient but fork-safe "select" or "poll" calls. |
1735 | because they rely on inefficient but fork-safe "select" or "poll" calls. |
1613 | Only EV is fully fork-aware. |
1736 | Only EV is fully fork-aware. |
1614 | |
1737 | |
1615 | If you have to fork, you must either do so *before* creating your first |
1738 | If you have to fork, you must either do so *before* creating your first |
1616 | watcher OR you must not use AnyEvent at all in the child. |
1739 | watcher OR you must not use AnyEvent at all in the child OR you must do |
|
|
1740 | something completely out of the scope of AnyEvent. |
1617 | |
1741 | |
1618 | SECURITY CONSIDERATIONS |
1742 | SECURITY CONSIDERATIONS |
1619 | AnyEvent can be forced to load any event model via |
1743 | AnyEvent can be forced to load any event model via |
1620 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
1744 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
1621 | to execute arbitrary code or directly gain access, it can easily be used |
1745 | to execute arbitrary code or directly gain access, it can easily be used |
… | |
… | |
1653 | Event::Lib, Qt, POE. |
1777 | Event::Lib, Qt, POE. |
1654 | |
1778 | |
1655 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1779 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1656 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1780 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1657 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
1781 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
1658 | AnyEvent::Impl::IOAsync. |
1782 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. |
1659 | |
1783 | |
1660 | Non-blocking file handles, sockets, TCP clients and servers: |
1784 | Non-blocking file handles, sockets, TCP clients and servers: |
1661 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
1785 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
1662 | |
1786 | |
1663 | Asynchronous DNS: AnyEvent::DNS. |
1787 | Asynchronous DNS: AnyEvent::DNS. |