1 | =head1 NAME |
1 | =head1 => NAME |
2 | |
2 | |
3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - provide framework for multiple event loops |
4 | |
4 | |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
6 | |
6 | |
… | |
… | |
57 | as those use one of the supported event loops. It is trivial to add new |
57 | as those use one of the supported event loops. It is trivial to add new |
58 | event loops to AnyEvent, too, so it is future-proof). |
58 | event loops to AnyEvent, too, so it is future-proof). |
59 | |
59 | |
60 | In addition to being free of having to use I<the one and only true event |
60 | In addition to being free of having to use I<the one and only true event |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
62 | modules, you get an enourmous amount of code and strict rules you have to |
62 | modules, you get an enormous amount of code and strict rules you have to |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
65 | technically possible. |
66 | |
66 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
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108 | |
108 | |
109 | =head1 WATCHERS |
109 | =head1 WATCHERS |
110 | |
110 | |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
112 | stores relevant data for each kind of event you are waiting for, such as |
112 | stores relevant data for each kind of event you are waiting for, such as |
113 | the callback to call, the filehandle to watch, etc. |
113 | the callback to call, the file handle to watch, etc. |
114 | |
114 | |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
116 | creating a watcher it will immediately "watch" for events and invoke the |
116 | creating a watcher it will immediately "watch" for events and invoke the |
117 | callback when the event occurs (of course, only when the event model |
117 | callback when the event occurs (of course, only when the event model |
118 | is in control). |
118 | is in control). |
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237 | |
237 | |
238 | Although the callback might get passed parameters, their value and |
238 | Although the callback might get passed parameters, their value and |
239 | presence is undefined and you cannot rely on them. Portable AnyEvent |
239 | presence is undefined and you cannot rely on them. Portable AnyEvent |
240 | callbacks cannot use arguments passed to signal watcher callbacks. |
240 | callbacks cannot use arguments passed to signal watcher callbacks. |
241 | |
241 | |
242 | Multiple signal occurances can be clumped together into one callback |
242 | Multiple signal occurrences can be clumped together into one callback |
243 | invocation, and callback invocation will be synchronous. synchronous means |
243 | invocation, and callback invocation will be synchronous. Synchronous means |
244 | that it might take a while until the signal gets handled by the process, |
244 | that it might take a while until the signal gets handled by the process, |
245 | but it is guarenteed not to interrupt any other callbacks. |
245 | but it is guaranteed not to interrupt any other callbacks. |
246 | |
246 | |
247 | The main advantage of using these watchers is that you can share a signal |
247 | The main advantage of using these watchers is that you can share a signal |
248 | between multiple watchers. |
248 | between multiple watchers. |
249 | |
249 | |
250 | This watcher might use C<%SIG>, so programs overwriting those signals |
250 | This watcher might use C<%SIG>, so programs overwriting those signals |
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310 | Condition variables can be created by calling the C<< AnyEvent->condvar |
310 | Condition variables can be created by calling the C<< AnyEvent->condvar |
311 | >> method, usually without arguments. The only argument pair allowed is |
311 | >> method, usually without arguments. The only argument pair allowed is |
312 | C<cb>, which specifies a callback to be called when the condition variable |
312 | C<cb>, which specifies a callback to be called when the condition variable |
313 | becomes true. |
313 | becomes true. |
314 | |
314 | |
315 | After creation, the conditon variable is "false" until it becomes "true" |
315 | After creation, the condition variable is "false" until it becomes "true" |
316 | by calling the C<send> method. |
316 | by calling the C<send> method (or calling the condition variable as if it |
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317 | were a callback, read about the caveats in the description for the C<< |
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318 | ->send >> method). |
317 | |
319 | |
318 | Condition variables are similar to callbacks, except that you can |
320 | Condition variables are similar to callbacks, except that you can |
319 | optionally wait for them. They can also be called merge points - points |
321 | optionally wait for them. They can also be called merge points - points |
320 | in time where multiple outstandign events have been processed. And yet |
322 | in time where multiple outstanding events have been processed. And yet |
321 | another way to call them is transations - each condition variable can be |
323 | another way to call them is transactions - each condition variable can be |
322 | used to represent a transaction, which finishes at some point and delivers |
324 | used to represent a transaction, which finishes at some point and delivers |
323 | a result. |
325 | a result. |
324 | |
326 | |
325 | Condition variables are very useful to signal that something has finished, |
327 | Condition variables are very useful to signal that something has finished, |
326 | for example, if you write a module that does asynchronous http requests, |
328 | for example, if you write a module that does asynchronous http requests, |
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332 | you can block your main program until an event occurs - for example, you |
334 | you can block your main program until an event occurs - for example, you |
333 | could C<< ->recv >> in your main program until the user clicks the Quit |
335 | could C<< ->recv >> in your main program until the user clicks the Quit |
334 | button of your app, which would C<< ->send >> the "quit" event. |
336 | button of your app, which would C<< ->send >> the "quit" event. |
335 | |
337 | |
336 | Note that condition variables recurse into the event loop - if you have |
338 | Note that condition variables recurse into the event loop - if you have |
337 | two pieces of code that call C<< ->recv >> in a round-robbin fashion, you |
339 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
338 | lose. Therefore, condition variables are good to export to your caller, but |
340 | lose. Therefore, condition variables are good to export to your caller, but |
339 | you should avoid making a blocking wait yourself, at least in callbacks, |
341 | you should avoid making a blocking wait yourself, at least in callbacks, |
340 | as this asks for trouble. |
342 | as this asks for trouble. |
341 | |
343 | |
342 | Condition variables are represented by hash refs in perl, and the keys |
344 | Condition variables are represented by hash refs in perl, and the keys |
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347 | |
349 | |
348 | There are two "sides" to a condition variable - the "producer side" which |
350 | There are two "sides" to a condition variable - the "producer side" which |
349 | eventually calls C<< -> send >>, and the "consumer side", which waits |
351 | eventually calls C<< -> send >>, and the "consumer side", which waits |
350 | for the send to occur. |
352 | for the send to occur. |
351 | |
353 | |
352 | Example: |
354 | Example: wait for a timer. |
353 | |
355 | |
354 | # wait till the result is ready |
356 | # wait till the result is ready |
355 | my $result_ready = AnyEvent->condvar; |
357 | my $result_ready = AnyEvent->condvar; |
356 | |
358 | |
357 | # do something such as adding a timer |
359 | # do something such as adding a timer |
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365 | |
367 | |
366 | # this "blocks" (while handling events) till the callback |
368 | # this "blocks" (while handling events) till the callback |
367 | # calls send |
369 | # calls send |
368 | $result_ready->recv; |
370 | $result_ready->recv; |
369 | |
371 | |
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372 | Example: wait for a timer, but take advantage of the fact that |
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373 | condition variables are also code references. |
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374 | |
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375 | my $done = AnyEvent->condvar; |
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376 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
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377 | $done->recv; |
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378 | |
370 | =head3 METHODS FOR PRODUCERS |
379 | =head3 METHODS FOR PRODUCERS |
371 | |
380 | |
372 | These methods should only be used by the producing side, i.e. the |
381 | These methods should only be used by the producing side, i.e. the |
373 | code/module that eventually sends the signal. Note that it is also |
382 | code/module that eventually sends the signal. Note that it is also |
374 | the producer side which creates the condvar in most cases, but it isn't |
383 | the producer side which creates the condvar in most cases, but it isn't |
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385 | If a callback has been set on the condition variable, it is called |
394 | If a callback has been set on the condition variable, it is called |
386 | immediately from within send. |
395 | immediately from within send. |
387 | |
396 | |
388 | Any arguments passed to the C<send> call will be returned by all |
397 | Any arguments passed to the C<send> call will be returned by all |
389 | future C<< ->recv >> calls. |
398 | future C<< ->recv >> calls. |
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399 | |
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400 | Condition variables are overloaded so one can call them directly |
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401 | (as a code reference). Calling them directly is the same as calling |
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402 | C<send>. Note, however, that many C-based event loops do not handle |
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403 | overloading, so as tempting as it may be, passing a condition variable |
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404 | instead of a callback does not work. Both the pure perl and EV loops |
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405 | support overloading, however, as well as all functions that use perl to |
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406 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
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407 | example). |
390 | |
408 | |
391 | =item $cv->croak ($error) |
409 | =item $cv->croak ($error) |
392 | |
410 | |
393 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
411 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
394 | C<Carp::croak> with the given error message/object/scalar. |
412 | C<Carp::croak> with the given error message/object/scalar. |
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443 | doesn't execute once). |
461 | doesn't execute once). |
444 | |
462 | |
445 | This is the general pattern when you "fan out" into multiple subrequests: |
463 | This is the general pattern when you "fan out" into multiple subrequests: |
446 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
464 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
447 | is called at least once, and then, for each subrequest you start, call |
465 | is called at least once, and then, for each subrequest you start, call |
448 | C<begin> and for eahc subrequest you finish, call C<end>. |
466 | C<begin> and for each subrequest you finish, call C<end>. |
449 | |
467 | |
450 | =back |
468 | =back |
451 | |
469 | |
452 | =head3 METHODS FOR CONSUMERS |
470 | =head3 METHODS FOR CONSUMERS |
453 | |
471 | |
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475 | (programs might want to do that to stay interactive), so I<if you are |
493 | (programs might want to do that to stay interactive), so I<if you are |
476 | using this from a module, never require a blocking wait>, but let the |
494 | using this from a module, never require a blocking wait>, but let the |
477 | caller decide whether the call will block or not (for example, by coupling |
495 | caller decide whether the call will block or not (for example, by coupling |
478 | condition variables with some kind of request results and supporting |
496 | condition variables with some kind of request results and supporting |
479 | callbacks so the caller knows that getting the result will not block, |
497 | callbacks so the caller knows that getting the result will not block, |
480 | while still suppporting blocking waits if the caller so desires). |
498 | while still supporting blocking waits if the caller so desires). |
481 | |
499 | |
482 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
500 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
483 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
501 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
484 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
502 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
485 | can supply. |
503 | can supply. |
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601 | |
619 | |
602 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
620 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
603 | do anything special (it does not need to be event-based) and let AnyEvent |
621 | do anything special (it does not need to be event-based) and let AnyEvent |
604 | decide which implementation to chose if some module relies on it. |
622 | decide which implementation to chose if some module relies on it. |
605 | |
623 | |
606 | If the main program relies on a specific event model. For example, in |
624 | If the main program relies on a specific event model - for example, in |
607 | Gtk2 programs you have to rely on the Glib module. You should load the |
625 | Gtk2 programs you have to rely on the Glib module - you should load the |
608 | event module before loading AnyEvent or any module that uses it: generally |
626 | event module before loading AnyEvent or any module that uses it: generally |
609 | speaking, you should load it as early as possible. The reason is that |
627 | speaking, you should load it as early as possible. The reason is that |
610 | modules might create watchers when they are loaded, and AnyEvent will |
628 | modules might create watchers when they are loaded, and AnyEvent will |
611 | decide on the event model to use as soon as it creates watchers, and it |
629 | decide on the event model to use as soon as it creates watchers, and it |
612 | might chose the wrong one unless you load the correct one yourself. |
630 | might chose the wrong one unless you load the correct one yourself. |
613 | |
631 | |
614 | You can chose to use a rather inefficient pure-perl implementation by |
632 | You can chose to use a pure-perl implementation by loading the |
615 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
633 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
616 | behaviour everywhere, but letting AnyEvent chose is generally better. |
634 | everywhere, but letting AnyEvent chose the model is generally better. |
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635 | |
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636 | =head2 MAINLOOP EMULATION |
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637 | |
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638 | Sometimes (often for short test scripts, or even standalone programs who |
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639 | only want to use AnyEvent), you do not want to run a specific event loop. |
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640 | |
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641 | In that case, you can use a condition variable like this: |
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642 | |
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643 | AnyEvent->condvar->recv; |
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644 | |
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645 | This has the effect of entering the event loop and looping forever. |
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646 | |
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647 | Note that usually your program has some exit condition, in which case |
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648 | it is better to use the "traditional" approach of storing a condition |
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649 | variable somewhere, waiting for it, and sending it when the program should |
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650 | exit cleanly. |
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651 | |
617 | |
652 | |
618 | =head1 OTHER MODULES |
653 | =head1 OTHER MODULES |
619 | |
654 | |
620 | The following is a non-exhaustive list of additional modules that use |
655 | The following is a non-exhaustive list of additional modules that use |
621 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
656 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
… | |
… | |
631 | |
666 | |
632 | =item L<AnyEvent::Handle> |
667 | =item L<AnyEvent::Handle> |
633 | |
668 | |
634 | Provide read and write buffers and manages watchers for reads and writes. |
669 | Provide read and write buffers and manages watchers for reads and writes. |
635 | |
670 | |
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671 | =item L<AnyEvent::Socket> |
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672 | |
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673 | Provides various utility functions for (internet protocol) sockets, |
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674 | addresses and name resolution. Also functions to create non-blocking tcp |
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675 | connections or tcp servers, with IPv6 and SRV record support and more. |
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676 | |
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677 | =item L<AnyEvent::DNS> |
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678 | |
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679 | Provides rich asynchronous DNS resolver capabilities. |
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680 | |
636 | =item L<AnyEvent::HTTPD> |
681 | =item L<AnyEvent::HTTPD> |
637 | |
682 | |
638 | Provides a simple web application server framework. |
683 | Provides a simple web application server framework. |
639 | |
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640 | =item L<AnyEvent::DNS> |
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641 | |
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642 | Provides asynchronous DNS resolver capabilities, beyond what |
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643 | L<AnyEvent::Util> offers. |
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644 | |
684 | |
645 | =item L<AnyEvent::FastPing> |
685 | =item L<AnyEvent::FastPing> |
646 | |
686 | |
647 | The fastest ping in the west. |
687 | The fastest ping in the west. |
648 | |
688 | |
… | |
… | |
691 | no warnings; |
731 | no warnings; |
692 | use strict; |
732 | use strict; |
693 | |
733 | |
694 | use Carp; |
734 | use Carp; |
695 | |
735 | |
696 | our $VERSION = '3.4'; |
736 | our $VERSION = '4.03'; |
697 | our $MODEL; |
737 | our $MODEL; |
698 | |
738 | |
699 | our $AUTOLOAD; |
739 | our $AUTOLOAD; |
700 | our @ISA; |
740 | our @ISA; |
701 | |
741 | |
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742 | our @REGISTRY; |
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743 | |
702 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
744 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
703 | |
745 | |
704 | our @REGISTRY; |
746 | our %PROTOCOL; # (ipv4|ipv6) => (1|2) |
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747 | |
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748 | { |
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749 | my $idx; |
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750 | $PROTOCOL{$_} = ++$idx |
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751 | for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
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752 | } |
705 | |
753 | |
706 | my @models = ( |
754 | my @models = ( |
707 | [EV:: => AnyEvent::Impl::EV::], |
755 | [EV:: => AnyEvent::Impl::EV::], |
708 | [Event:: => AnyEvent::Impl::Event::], |
756 | [Event:: => AnyEvent::Impl::Event::], |
709 | [Tk:: => AnyEvent::Impl::Tk::], |
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710 | [Wx:: => AnyEvent::Impl::POE::], |
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711 | [Prima:: => AnyEvent::Impl::POE::], |
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712 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
757 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
713 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
758 | # everything below here will not be autoprobed |
714 | [Glib:: => AnyEvent::Impl::Glib::], |
759 | # as the pureperl backend should work everywhere |
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760 | # and is usually faster |
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761 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
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762 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
715 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
763 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
716 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
764 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
717 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
765 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
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766 | [Wx:: => AnyEvent::Impl::POE::], |
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767 | [Prima:: => AnyEvent::Impl::POE::], |
718 | ); |
768 | ); |
719 | |
769 | |
720 | our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); |
770 | our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); |
721 | |
771 | |
722 | our @post_detect; |
772 | our @post_detect; |
… | |
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730 | 1 |
780 | 1 |
731 | } else { |
781 | } else { |
732 | push @post_detect, $cb; |
782 | push @post_detect, $cb; |
733 | |
783 | |
734 | defined wantarray |
784 | defined wantarray |
735 | ? bless \$cb, "AnyEvent::Util::Guard" |
785 | ? bless \$cb, "AnyEvent::Util::PostDetect" |
736 | : () |
786 | : () |
737 | } |
787 | } |
738 | } |
788 | } |
739 | |
789 | |
740 | sub AnyEvent::Util::Guard::DESTROY { |
790 | sub AnyEvent::Util::PostDetect::DESTROY { |
741 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
791 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
742 | } |
792 | } |
743 | |
793 | |
744 | sub detect() { |
794 | sub detect() { |
745 | unless ($MODEL) { |
795 | unless ($MODEL) { |
… | |
… | |
811 | package AnyEvent::Base; |
861 | package AnyEvent::Base; |
812 | |
862 | |
813 | # default implementation for ->condvar |
863 | # default implementation for ->condvar |
814 | |
864 | |
815 | sub condvar { |
865 | sub condvar { |
816 | bless {}, "AnyEvent::Base::CondVar" |
866 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
817 | } |
867 | } |
818 | |
868 | |
819 | # default implementation for ->signal |
869 | # default implementation for ->signal |
820 | |
870 | |
821 | our %SIG_CB; |
871 | our %SIG_CB; |
… | |
… | |
895 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
945 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
896 | |
946 | |
897 | undef $CHLD_W unless keys %PID_CB; |
947 | undef $CHLD_W unless keys %PID_CB; |
898 | } |
948 | } |
899 | |
949 | |
900 | package AnyEvent::Base::CondVar; |
950 | package AnyEvent::CondVar; |
901 | |
951 | |
902 | # wake up the waiter |
952 | our @ISA = AnyEvent::CondVar::Base::; |
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953 | |
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954 | package AnyEvent::CondVar::Base; |
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955 | |
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956 | use overload |
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957 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
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958 | fallback => 1; |
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959 | |
903 | sub _send { |
960 | sub _send { |
904 | &{ delete $_[0]{_ae_cb} } if $_[0]{_ae_cb}; |
961 | # nop |
905 | } |
962 | } |
906 | |
963 | |
907 | sub send { |
964 | sub send { |
908 | my $cv = shift; |
965 | my $cv = shift; |
909 | $cv->{_ae_sent} = [@_]; |
966 | $cv->{_ae_sent} = [@_]; |
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967 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
910 | $cv->_send; |
968 | $cv->_send; |
911 | } |
969 | } |
912 | |
970 | |
913 | sub croak { |
971 | sub croak { |
914 | $_[0]{_ae_croak} = $_[1]; |
972 | $_[0]{_ae_croak} = $_[1]; |
… | |
… | |
917 | |
975 | |
918 | sub ready { |
976 | sub ready { |
919 | $_[0]{_ae_sent} |
977 | $_[0]{_ae_sent} |
920 | } |
978 | } |
921 | |
979 | |
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980 | sub _wait { |
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981 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
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982 | } |
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983 | |
922 | sub recv { |
984 | sub recv { |
923 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
985 | $_[0]->_wait; |
924 | |
986 | |
925 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
987 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
926 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
988 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
927 | } |
989 | } |
928 | |
990 | |
… | |
… | |
936 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
998 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
937 | } |
999 | } |
938 | |
1000 | |
939 | sub end { |
1001 | sub end { |
940 | return if --$_[0]{_ae_counter}; |
1002 | return if --$_[0]{_ae_counter}; |
941 | &{ $_[0]{_ae_end_cb} } if $_[0]{_ae_end_cb}; |
1003 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
942 | } |
1004 | } |
943 | |
1005 | |
944 | # undocumented/compatibility with pre-3.4 |
1006 | # undocumented/compatibility with pre-3.4 |
945 | *broadcast = \&send; |
1007 | *broadcast = \&send; |
946 | *wait = \&recv; |
1008 | *wait = \&_wait; |
947 | |
1009 | |
948 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1010 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
949 | |
1011 | |
950 | This is an advanced topic that you do not normally need to use AnyEvent in |
1012 | This is an advanced topic that you do not normally need to use AnyEvent in |
951 | a module. This section is only of use to event loop authors who want to |
1013 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
1008 | model it chooses. |
1070 | model it chooses. |
1009 | |
1071 | |
1010 | =item C<PERL_ANYEVENT_MODEL> |
1072 | =item C<PERL_ANYEVENT_MODEL> |
1011 | |
1073 | |
1012 | This can be used to specify the event model to be used by AnyEvent, before |
1074 | This can be used to specify the event model to be used by AnyEvent, before |
1013 | autodetection and -probing kicks in. It must be a string consisting |
1075 | auto detection and -probing kicks in. It must be a string consisting |
1014 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1076 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1015 | and the resulting module name is loaded and if the load was successful, |
1077 | and the resulting module name is loaded and if the load was successful, |
1016 | used as event model. If it fails to load AnyEvent will proceed with |
1078 | used as event model. If it fails to load AnyEvent will proceed with |
1017 | autodetection and -probing. |
1079 | auto detection and -probing. |
1018 | |
1080 | |
1019 | This functionality might change in future versions. |
1081 | This functionality might change in future versions. |
1020 | |
1082 | |
1021 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1083 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1022 | could start your program like this: |
1084 | could start your program like this: |
1023 | |
1085 | |
1024 | PERL_ANYEVENT_MODEL=Perl perl ... |
1086 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1087 | |
|
|
1088 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1089 | |
|
|
1090 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1091 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1092 | of auto probing). |
|
|
1093 | |
|
|
1094 | Must be set to a comma-separated list of protocols or address families, |
|
|
1095 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1096 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1097 | list. |
|
|
1098 | |
|
|
1099 | This variable can effectively be used for denial-of-service attacks |
|
|
1100 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1101 | small, as the program has to handle connection errors already- |
|
|
1102 | |
|
|
1103 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1104 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1105 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1106 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1107 | IPv6, but prefer IPv6 over IPv4. |
|
|
1108 | |
|
|
1109 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1110 | |
|
|
1111 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1112 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1113 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1114 | default. |
|
|
1115 | |
|
|
1116 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1117 | EDNS0 in its DNS requests. |
1025 | |
1118 | |
1026 | =back |
1119 | =back |
1027 | |
1120 | |
1028 | =head1 EXAMPLE PROGRAM |
1121 | =head1 EXAMPLE PROGRAM |
1029 | |
1122 | |
… | |
… | |
1040 | poll => 'r', |
1133 | poll => 'r', |
1041 | cb => sub { |
1134 | cb => sub { |
1042 | warn "io event <$_[0]>\n"; # will always output <r> |
1135 | warn "io event <$_[0]>\n"; # will always output <r> |
1043 | chomp (my $input = <STDIN>); # read a line |
1136 | chomp (my $input = <STDIN>); # read a line |
1044 | warn "read: $input\n"; # output what has been read |
1137 | warn "read: $input\n"; # output what has been read |
1045 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1138 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
1046 | }, |
1139 | }, |
1047 | ); |
1140 | ); |
1048 | |
1141 | |
1049 | my $time_watcher; # can only be used once |
1142 | my $time_watcher; # can only be used once |
1050 | |
1143 | |
… | |
… | |
1055 | }); |
1148 | }); |
1056 | } |
1149 | } |
1057 | |
1150 | |
1058 | new_timer; # create first timer |
1151 | new_timer; # create first timer |
1059 | |
1152 | |
1060 | $cv->wait; # wait until user enters /^q/i |
1153 | $cv->recv; # wait until user enters /^q/i |
1061 | |
1154 | |
1062 | =head1 REAL-WORLD EXAMPLE |
1155 | =head1 REAL-WORLD EXAMPLE |
1063 | |
1156 | |
1064 | Consider the L<Net::FCP> module. It features (among others) the following |
1157 | Consider the L<Net::FCP> module. It features (among others) the following |
1065 | API calls, which are to freenet what HTTP GET requests are to http: |
1158 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
1115 | syswrite $txn->{fh}, $txn->{request} |
1208 | syswrite $txn->{fh}, $txn->{request} |
1116 | or die "connection or write error"; |
1209 | or die "connection or write error"; |
1117 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1210 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1118 | |
1211 | |
1119 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1212 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1120 | result and signals any possible waiters that the request ahs finished: |
1213 | result and signals any possible waiters that the request has finished: |
1121 | |
1214 | |
1122 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1215 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1123 | |
1216 | |
1124 | if (end-of-file or data complete) { |
1217 | if (end-of-file or data complete) { |
1125 | $txn->{result} = $txn->{buf}; |
1218 | $txn->{result} = $txn->{buf}; |
1126 | $txn->{finished}->broadcast; |
1219 | $txn->{finished}->send; |
1127 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1220 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1128 | } |
1221 | } |
1129 | |
1222 | |
1130 | The C<result> method, finally, just waits for the finished signal (if the |
1223 | The C<result> method, finally, just waits for the finished signal (if the |
1131 | request was already finished, it doesn't wait, of course, and returns the |
1224 | request was already finished, it doesn't wait, of course, and returns the |
1132 | data: |
1225 | data: |
1133 | |
1226 | |
1134 | $txn->{finished}->wait; |
1227 | $txn->{finished}->recv; |
1135 | return $txn->{result}; |
1228 | return $txn->{result}; |
1136 | |
1229 | |
1137 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1230 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1138 | that occured during request processing. The C<result> method detects |
1231 | that occurred during request processing. The C<result> method detects |
1139 | whether an exception as thrown (it is stored inside the $txn object) |
1232 | whether an exception as thrown (it is stored inside the $txn object) |
1140 | and just throws the exception, which means connection errors and other |
1233 | and just throws the exception, which means connection errors and other |
1141 | problems get reported tot he code that tries to use the result, not in a |
1234 | problems get reported tot he code that tries to use the result, not in a |
1142 | random callback. |
1235 | random callback. |
1143 | |
1236 | |
… | |
… | |
1174 | |
1267 | |
1175 | my $quit = AnyEvent->condvar; |
1268 | my $quit = AnyEvent->condvar; |
1176 | |
1269 | |
1177 | $fcp->txn_client_get ($url)->cb (sub { |
1270 | $fcp->txn_client_get ($url)->cb (sub { |
1178 | ... |
1271 | ... |
1179 | $quit->broadcast; |
1272 | $quit->send; |
1180 | }); |
1273 | }); |
1181 | |
1274 | |
1182 | $quit->wait; |
1275 | $quit->recv; |
1183 | |
1276 | |
1184 | |
1277 | |
1185 | =head1 BENCHMARKS |
1278 | =head1 BENCHMARKS |
1186 | |
1279 | |
1187 | To give you an idea of the performance and overheads that AnyEvent adds |
1280 | To give you an idea of the performance and overheads that AnyEvent adds |
… | |
… | |
1189 | of various event loops I prepared some benchmarks. |
1282 | of various event loops I prepared some benchmarks. |
1190 | |
1283 | |
1191 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1284 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1192 | |
1285 | |
1193 | Here is a benchmark of various supported event models used natively and |
1286 | Here is a benchmark of various supported event models used natively and |
1194 | through anyevent. The benchmark creates a lot of timers (with a zero |
1287 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
1195 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1288 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1196 | which it is), lets them fire exactly once and destroys them again. |
1289 | which it is), lets them fire exactly once and destroys them again. |
1197 | |
1290 | |
1198 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1291 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1199 | distribution. |
1292 | distribution. |
… | |
… | |
1216 | all watchers, to avoid adding memory overhead. That means closure creation |
1309 | all watchers, to avoid adding memory overhead. That means closure creation |
1217 | and memory usage is not included in the figures. |
1310 | and memory usage is not included in the figures. |
1218 | |
1311 | |
1219 | I<invoke> is the time, in microseconds, used to invoke a simple |
1312 | I<invoke> is the time, in microseconds, used to invoke a simple |
1220 | callback. The callback simply counts down a Perl variable and after it was |
1313 | callback. The callback simply counts down a Perl variable and after it was |
1221 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1314 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
1222 | signal the end of this phase. |
1315 | signal the end of this phase. |
1223 | |
1316 | |
1224 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1317 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1225 | watcher. |
1318 | watcher. |
1226 | |
1319 | |
… | |
… | |
1322 | |
1415 | |
1323 | =back |
1416 | =back |
1324 | |
1417 | |
1325 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1418 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1326 | |
1419 | |
1327 | This benchmark atcually benchmarks the event loop itself. It works by |
1420 | This benchmark actually benchmarks the event loop itself. It works by |
1328 | creating a number of "servers": each server consists of a socketpair, a |
1421 | creating a number of "servers": each server consists of a socket pair, a |
1329 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1422 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1330 | watcher waiting for input on one side of the socket. Each time the socket |
1423 | watcher waiting for input on one side of the socket. Each time the socket |
1331 | watcher reads a byte it will write that byte to a random other "server". |
1424 | watcher reads a byte it will write that byte to a random other "server". |
1332 | |
1425 | |
1333 | The effect is that there will be a lot of I/O watchers, only part of which |
1426 | The effect is that there will be a lot of I/O watchers, only part of which |
1334 | are active at any one point (so there is a constant number of active |
1427 | are active at any one point (so there is a constant number of active |
1335 | fds for each loop iterstaion, but which fds these are is random). The |
1428 | fds for each loop iteration, but which fds these are is random). The |
1336 | timeout is reset each time something is read because that reflects how |
1429 | timeout is reset each time something is read because that reflects how |
1337 | most timeouts work (and puts extra pressure on the event loops). |
1430 | most timeouts work (and puts extra pressure on the event loops). |
1338 | |
1431 | |
1339 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1432 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1340 | (1%) are active. This mirrors the activity of large servers with many |
1433 | (1%) are active. This mirrors the activity of large servers with many |
1341 | connections, most of which are idle at any one point in time. |
1434 | connections, most of which are idle at any one point in time. |
1342 | |
1435 | |
1343 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1436 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1344 | distribution. |
1437 | distribution. |
… | |
… | |
1346 | =head3 Explanation of the columns |
1439 | =head3 Explanation of the columns |
1347 | |
1440 | |
1348 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1441 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1349 | each server has a read and write socket end). |
1442 | each server has a read and write socket end). |
1350 | |
1443 | |
1351 | I<create> is the time it takes to create a socketpair (which is |
1444 | I<create> is the time it takes to create a socket pair (which is |
1352 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1445 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1353 | |
1446 | |
1354 | I<request>, the most important value, is the time it takes to handle a |
1447 | I<request>, the most important value, is the time it takes to handle a |
1355 | single "request", that is, reading the token from the pipe and forwarding |
1448 | single "request", that is, reading the token from the pipe and forwarding |
1356 | it to another server. This includes deleting the old timeout and creating |
1449 | it to another server. This includes deleting the old timeout and creating |
… | |
… | |
1429 | speed most when you have lots of watchers, not when you only have a few of |
1522 | speed most when you have lots of watchers, not when you only have a few of |
1430 | them). |
1523 | them). |
1431 | |
1524 | |
1432 | EV is again fastest. |
1525 | EV is again fastest. |
1433 | |
1526 | |
1434 | Perl again comes second. It is noticably faster than the C-based event |
1527 | Perl again comes second. It is noticeably faster than the C-based event |
1435 | loops Event and Glib, although the difference is too small to really |
1528 | loops Event and Glib, although the difference is too small to really |
1436 | matter. |
1529 | matter. |
1437 | |
1530 | |
1438 | POE also performs much better in this case, but is is still far behind the |
1531 | POE also performs much better in this case, but is is still far behind the |
1439 | others. |
1532 | others. |
… | |
… | |
1479 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
1572 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
1480 | |
1573 | |
1481 | |
1574 | |
1482 | =head1 SEE ALSO |
1575 | =head1 SEE ALSO |
1483 | |
1576 | |
|
|
1577 | Utility functions: L<AnyEvent::Util>. |
|
|
1578 | |
1484 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1579 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1485 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1580 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1486 | |
1581 | |
1487 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1582 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1488 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1583 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1489 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1584 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1490 | L<AnyEvent::Impl::POE>. |
1585 | L<AnyEvent::Impl::POE>. |
1491 | |
1586 | |
|
|
1587 | Non-blocking file handles, sockets, TCP clients and |
|
|
1588 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
1589 | |
|
|
1590 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
1591 | |
1492 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
1592 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
1493 | |
1593 | |
1494 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1594 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1495 | |
1595 | |
1496 | |
1596 | |
1497 | =head1 AUTHOR |
1597 | =head1 AUTHOR |
1498 | |
1598 | |
1499 | Marc Lehmann <schmorp@schmorp.de> |
1599 | Marc Lehmann <schmorp@schmorp.de> |