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Revision 1.132 by root, Sun May 25 01:05:27 2008 UTC

1=head1 NAME 1=head1 => NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6 6
7=head1 SYNOPSIS 7=head1 SYNOPSIS
8 8
9 use AnyEvent; 9 use AnyEvent;
10 10
15 my $w = AnyEvent->timer (after => $seconds, cb => sub { 15 my $w = AnyEvent->timer (after => $seconds, cb => sub {
16 ... 16 ...
17 }); 17 });
18 18
19 my $w = AnyEvent->condvar; # stores whether a condition was flagged 19 my $w = AnyEvent->condvar; # stores whether a condition was flagged
20 $w->send; # wake up current and all future recv's
20 $w->wait; # enters "main loop" till $condvar gets ->broadcast 21 $w->recv; # enters "main loop" till $condvar gets ->send
21 $w->broadcast; # wake up current and all future wait's
22 22
23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24 24
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent? 26nowadays. So what is different about AnyEvent?
57as those use one of the supported event loops. It is trivial to add new 57as those use one of the supported event loops. It is trivial to add new
58event loops to AnyEvent, too, so it is future-proof). 58event loops to AnyEvent, too, so it is future-proof).
59 59
60In addition to being free of having to use I<the one and only true event 60In addition to being free of having to use I<the one and only true event
61model>, AnyEvent also is free of bloat and policy: with POE or similar 61model>, AnyEvent also is free of bloat and policy: with POE or similar
62modules, you get an enourmous amount of code and strict rules you have to 62modules, you get an enormous amount of code and strict rules you have to
63follow. AnyEvent, on the other hand, is lean and up to the point, by only 63follow. AnyEvent, on the other hand, is lean and up to the point, by only
64offering the functionality that is necessary, in as thin as a wrapper as 64offering the functionality that is necessary, in as thin as a wrapper as
65technically possible. 65technically possible.
66 66
67Of course, if you want lots of policy (this can arguably be somewhat 67Of course, if you want lots of policy (this can arguably be somewhat
78The interface itself is vaguely similar, but not identical to the L<Event> 78The interface itself is vaguely similar, but not identical to the L<Event>
79module. 79module.
80 80
81During the first call of any watcher-creation method, the module tries 81During the first call of any watcher-creation method, the module tries
82to detect the currently loaded event loop by probing whether one of the 82to detect the currently loaded event loop by probing whether one of the
83following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, 83following modules is already loaded: L<EV>,
84L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, 84L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
85L<POE>. The first one found is used. If none are found, the module tries 85L<POE>. The first one found is used. If none are found, the module tries
86to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl 86to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
87adaptor should always succeed) in the order given. The first one that can 87adaptor should always succeed) in the order given. The first one that can
88be successfully loaded will be used. If, after this, still none could be 88be successfully loaded will be used. If, after this, still none could be
108 108
109=head1 WATCHERS 109=head1 WATCHERS
110 110
111AnyEvent has the central concept of a I<watcher>, which is an object that 111AnyEvent has the central concept of a I<watcher>, which is an object that
112stores relevant data for each kind of event you are waiting for, such as 112stores relevant data for each kind of event you are waiting for, such as
113the callback to call, the filehandle to watch, etc. 113the callback to call, the file handle to watch, etc.
114 114
115These watchers are normal Perl objects with normal Perl lifetime. After 115These watchers are normal Perl objects with normal Perl lifetime. After
116creating a watcher it will immediately "watch" for events and invoke the 116creating a watcher it will immediately "watch" for events and invoke the
117callback when the event occurs (of course, only when the event model 117callback when the event occurs (of course, only when the event model
118is in control). 118is in control).
237 237
238Although the callback might get passed parameters, their value and 238Although the callback might get passed parameters, their value and
239presence is undefined and you cannot rely on them. Portable AnyEvent 239presence is undefined and you cannot rely on them. Portable AnyEvent
240callbacks cannot use arguments passed to signal watcher callbacks. 240callbacks cannot use arguments passed to signal watcher callbacks.
241 241
242Multiple signal occurances can be clumped together into one callback 242Multiple signal occurrences can be clumped together into one callback
243invocation, and callback invocation will be synchronous. synchronous means 243invocation, and callback invocation will be synchronous. Synchronous means
244that it might take a while until the signal gets handled by the process, 244that it might take a while until the signal gets handled by the process,
245but it is guarenteed not to interrupt any other callbacks. 245but it is guaranteed not to interrupt any other callbacks.
246 246
247The main advantage of using these watchers is that you can share a signal 247The main advantage of using these watchers is that you can share a signal
248between multiple watchers. 248between multiple watchers.
249 249
250This watcher might use C<%SIG>, so programs overwriting those signals 250This watcher might use C<%SIG>, so programs overwriting those signals
279 279
280Example: fork a process and wait for it 280Example: fork a process and wait for it
281 281
282 my $done = AnyEvent->condvar; 282 my $done = AnyEvent->condvar;
283 283
284 AnyEvent::detect; # force event module to be initialised
285
286 my $pid = fork or exit 5; 284 my $pid = fork or exit 5;
287 285
288 my $w = AnyEvent->child ( 286 my $w = AnyEvent->child (
289 pid => $pid, 287 pid => $pid,
290 cb => sub { 288 cb => sub {
291 my ($pid, $status) = @_; 289 my ($pid, $status) = @_;
292 warn "pid $pid exited with status $status"; 290 warn "pid $pid exited with status $status";
293 $done->broadcast; 291 $done->send;
294 }, 292 },
295 ); 293 );
296 294
297 # do something else, then wait for process exit 295 # do something else, then wait for process exit
298 $done->wait; 296 $done->recv;
299 297
300=head2 CONDITION VARIABLES 298=head2 CONDITION VARIABLES
301 299
302If you are familiar with some event loops you will know that all of them 300If you are familiar with some event loops you will know that all of them
303require you to run some blocking "loop", "run" or similar function that 301require you to run some blocking "loop", "run" or similar function that
312Condition variables can be created by calling the C<< AnyEvent->condvar 310Condition variables can be created by calling the C<< AnyEvent->condvar
313>> method, usually without arguments. The only argument pair allowed is 311>> method, usually without arguments. The only argument pair allowed is
314C<cb>, which specifies a callback to be called when the condition variable 312C<cb>, which specifies a callback to be called when the condition variable
315becomes true. 313becomes true.
316 314
317After creation, the conditon variable is "false" until it becomes "true" 315After creation, the condition variable is "false" until it becomes "true"
318by calling the C<broadcast> method. 316by calling the C<send> method (or calling the condition variable as if it
317were a callback).
319 318
320Condition variables are similar to callbacks, except that you can 319Condition variables are similar to callbacks, except that you can
321optionally wait for them. They can also be called merge points - points 320optionally wait for them. They can also be called merge points - points
322in time where multiple outstandign events have been processed. And yet 321in time where multiple outstanding events have been processed. And yet
323another way to call them is transations - each condition variable can be 322another way to call them is transactions - each condition variable can be
324used to represent a transaction, which finishes at some point and delivers 323used to represent a transaction, which finishes at some point and delivers
325a result. 324a result.
326 325
327Condition variables are very useful to signal that something has finished, 326Condition variables are very useful to signal that something has finished,
328for example, if you write a module that does asynchronous http requests, 327for example, if you write a module that does asynchronous http requests,
329then a condition variable would be the ideal candidate to signal the 328then a condition variable would be the ideal candidate to signal the
330availability of results. The user can either act when the callback is 329availability of results. The user can either act when the callback is
331called or can synchronously C<< ->wait >> for the results. 330called or can synchronously C<< ->recv >> for the results.
332 331
333You can also use them to simulate traditional event loops - for example, 332You can also use them to simulate traditional event loops - for example,
334you can block your main program until an event occurs - for example, you 333you can block your main program until an event occurs - for example, you
335could C<< ->wait >> in your main program until the user clicks the Quit 334could C<< ->recv >> in your main program until the user clicks the Quit
336button of your app, which would C<< ->broadcast >> the "quit" event. 335button of your app, which would C<< ->send >> the "quit" event.
337 336
338Note that condition variables recurse into the event loop - if you have 337Note that condition variables recurse into the event loop - if you have
339two pieces of code that call C<< ->wait >> in a round-robbin fashion, you 338two pieces of code that call C<< ->recv >> in a round-robin fashion, you
340lose. Therefore, condition variables are good to export to your caller, but 339lose. Therefore, condition variables are good to export to your caller, but
341you should avoid making a blocking wait yourself, at least in callbacks, 340you should avoid making a blocking wait yourself, at least in callbacks,
342as this asks for trouble. 341as this asks for trouble.
343 342
344Condition variables are represented by hash refs in perl, and the keys 343Condition variables are represented by hash refs in perl, and the keys
346easy (it is often useful to build your own transaction class on top of 345easy (it is often useful to build your own transaction class on top of
347AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call 346AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
348it's C<new> method in your own C<new> method. 347it's C<new> method in your own C<new> method.
349 348
350There are two "sides" to a condition variable - the "producer side" which 349There are two "sides" to a condition variable - the "producer side" which
351eventually calls C<< -> broadcast >>, and the "consumer side", which waits 350eventually calls C<< -> send >>, and the "consumer side", which waits
352for the broadcast to occur. 351for the send to occur.
353 352
354Example: 353Example: wait for a timer.
355 354
356 # wait till the result is ready 355 # wait till the result is ready
357 my $result_ready = AnyEvent->condvar; 356 my $result_ready = AnyEvent->condvar;
358 357
359 # do something such as adding a timer 358 # do something such as adding a timer
360 # or socket watcher the calls $result_ready->broadcast 359 # or socket watcher the calls $result_ready->send
361 # when the "result" is ready. 360 # when the "result" is ready.
362 # in this case, we simply use a timer: 361 # in this case, we simply use a timer:
363 my $w = AnyEvent->timer ( 362 my $w = AnyEvent->timer (
364 after => 1, 363 after => 1,
365 cb => sub { $result_ready->broadcast }, 364 cb => sub { $result_ready->send },
366 ); 365 );
367 366
368 # this "blocks" (while handling events) till the callback 367 # this "blocks" (while handling events) till the callback
369 # calls broadcast 368 # calls send
370 $result_ready->wait; 369 $result_ready->recv;
370
371Example: wait for a timer, but take advantage of the fact that
372condition variables are also code references.
373
374 my $done = AnyEvent->condvar;
375 my $delay = AnyEvent->timer (after => 5, cb => $done);
376 $done->recv;
371 377
372=head3 METHODS FOR PRODUCERS 378=head3 METHODS FOR PRODUCERS
373 379
374These methods should only be used by the producing side, i.e. the 380These methods should only be used by the producing side, i.e. the
375code/module that eventually broadcasts the signal. Note that it is also 381code/module that eventually sends the signal. Note that it is also
376the producer side which creates the condvar in most cases, but it isn't 382the producer side which creates the condvar in most cases, but it isn't
377uncommon for the consumer to create it as well. 383uncommon for the consumer to create it as well.
378 384
379=over 4 385=over 4
380 386
381=item $cv->broadcast (...) 387=item $cv->send (...)
382 388
383Flag the condition as ready - a running C<< ->wait >> and all further 389Flag the condition as ready - a running C<< ->recv >> and all further
384calls to C<wait> will (eventually) return after this method has been 390calls to C<recv> will (eventually) return after this method has been
385called. If nobody is waiting the broadcast will be remembered. 391called. If nobody is waiting the send will be remembered.
386 392
387If a callback has been set on the condition variable, it is called 393If a callback has been set on the condition variable, it is called
388immediately from within broadcast. 394immediately from within send.
389 395
390Any arguments passed to the C<broadcast> call will be returned by all 396Any arguments passed to the C<send> call will be returned by all
391future C<< ->wait >> calls. 397future C<< ->recv >> calls.
398
399Condition variables are overloaded so one can call them directly (as a
400code reference). Calling them directly is the same as calling C<send>.
392 401
393=item $cv->croak ($error) 402=item $cv->croak ($error)
394 403
395Similar to broadcast, but causes all call's wait C<< ->wait >> to invoke 404Similar to send, but causes all call's to C<< ->recv >> to invoke
396C<Carp::croak> with the given error message/object/scalar. 405C<Carp::croak> with the given error message/object/scalar.
397 406
398This can be used to signal any errors to the condition variable 407This can be used to signal any errors to the condition variable
399user/consumer. 408user/consumer.
400 409
401=item $cv->begin ([group callback]) 410=item $cv->begin ([group callback])
402 411
403=item $cv->end 412=item $cv->end
413
414These two methods are EXPERIMENTAL and MIGHT CHANGE.
404 415
405These two methods can be used to combine many transactions/events into 416These two methods can be used to combine many transactions/events into
406one. For example, a function that pings many hosts in parallel might want 417one. For example, a function that pings many hosts in parallel might want
407to use a condition variable for the whole process. 418to use a condition variable for the whole process.
408 419
409Every call to C<< ->begin >> will increment a counter, and every call to 420Every call to C<< ->begin >> will increment a counter, and every call to
410C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 421C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
411>>, the (last) callback passed to C<begin> will be executed. That callback 422>>, the (last) callback passed to C<begin> will be executed. That callback
412is I<supposed> to call C<< ->broadcast >>, but that is not required. If no 423is I<supposed> to call C<< ->send >>, but that is not required. If no
413callback was set, C<broadcast> will be called without any arguments. 424callback was set, C<send> will be called without any arguments.
414 425
415Let's clarify this with the ping example: 426Let's clarify this with the ping example:
416 427
417 my $cv = AnyEvent->condvar; 428 my $cv = AnyEvent->condvar;
418 429
419 my %result; 430 my %result;
420 $cv->begin (sub { $cv->broadcast (\%result) }); 431 $cv->begin (sub { $cv->send (\%result) });
421 432
422 for my $host (@list_of_hosts) { 433 for my $host (@list_of_hosts) {
423 $cv->begin; 434 $cv->begin;
424 ping_host_then_call_callback $host, sub { 435 ping_host_then_call_callback $host, sub {
425 $result{$host} = ...; 436 $result{$host} = ...;
428 } 439 }
429 440
430 $cv->end; 441 $cv->end;
431 442
432This code fragment supposedly pings a number of hosts and calls 443This code fragment supposedly pings a number of hosts and calls
433C<broadcast> after results for all then have have been gathered - in any 444C<send> after results for all then have have been gathered - in any
434order. To achieve this, the code issues a call to C<begin> when it starts 445order. To achieve this, the code issues a call to C<begin> when it starts
435each ping request and calls C<end> when it has received some result for 446each ping request and calls C<end> when it has received some result for
436it. Since C<begin> and C<end> only maintain a counter, the order in which 447it. Since C<begin> and C<end> only maintain a counter, the order in which
437results arrive is not relevant. 448results arrive is not relevant.
438 449
439There is an additional bracketing call to C<begin> and C<end> outside the 450There is an additional bracketing call to C<begin> and C<end> outside the
440loop, which serves two important purposes: first, it sets the callback 451loop, which serves two important purposes: first, it sets the callback
441to be called once the counter reaches C<0>, and second, it ensures that 452to be called once the counter reaches C<0>, and second, it ensures that
442broadcast is called even when C<no> hosts are being pinged (the loop 453C<send> is called even when C<no> hosts are being pinged (the loop
443doesn't execute once). 454doesn't execute once).
444 455
445This is the general pattern when you "fan out" into multiple subrequests: 456This is the general pattern when you "fan out" into multiple subrequests:
446use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 457use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447is called at least once, and then, for each subrequest you start, call 458is called at least once, and then, for each subrequest you start, call
448C<begin> and for eahc subrequest you finish, call C<end>. 459C<begin> and for each subrequest you finish, call C<end>.
449 460
450=back 461=back
451 462
452=head3 METHODS FOR CONSUMERS 463=head3 METHODS FOR CONSUMERS
453 464
454These methods should only be used by the consuming side, i.e. the 465These methods should only be used by the consuming side, i.e. the
455code awaits the condition. 466code awaits the condition.
456 467
457=item $cv->wait 468=over 4
458 469
470=item $cv->recv
471
459Wait (blocking if necessary) until the C<< ->broadcast >> or C<< ->croak 472Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
460>> methods have been called on c<$cv>, while servicing other watchers 473>> methods have been called on c<$cv>, while servicing other watchers
461normally. 474normally.
462 475
463You can only wait once on a condition - additional calls are valid but 476You can only wait once on a condition - additional calls are valid but
464will return immediately. 477will return immediately.
465 478
466If an error condition has been set by calling C<< ->croak >>, then this 479If an error condition has been set by calling C<< ->croak >>, then this
467function will call C<croak>. 480function will call C<croak>.
468 481
469In list context, all parameters passed to C<broadcast> will be returned, 482In list context, all parameters passed to C<send> will be returned,
470in scalar context only the first one will be returned. 483in scalar context only the first one will be returned.
471 484
472Not all event models support a blocking wait - some die in that case 485Not all event models support a blocking wait - some die in that case
473(programs might want to do that to stay interactive), so I<if you are 486(programs might want to do that to stay interactive), so I<if you are
474using this from a module, never require a blocking wait>, but let the 487using this from a module, never require a blocking wait>, but let the
475caller decide whether the call will block or not (for example, by coupling 488caller decide whether the call will block or not (for example, by coupling
476condition variables with some kind of request results and supporting 489condition variables with some kind of request results and supporting
477callbacks so the caller knows that getting the result will not block, 490callbacks so the caller knows that getting the result will not block,
478while still suppporting blocking waits if the caller so desires). 491while still supporting blocking waits if the caller so desires).
479 492
480Another reason I<never> to C<< ->wait >> in a module is that you cannot 493Another reason I<never> to C<< ->recv >> in a module is that you cannot
481sensibly have two C<< ->wait >>'s in parallel, as that would require 494sensibly have two C<< ->recv >>'s in parallel, as that would require
482multiple interpreters or coroutines/threads, none of which C<AnyEvent> 495multiple interpreters or coroutines/threads, none of which C<AnyEvent>
483can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and 496can supply.
484L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
485from different coroutines, however).
486 497
498The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
499fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
500versions and also integrates coroutines into AnyEvent, making blocking
501C<< ->recv >> calls perfectly safe as long as they are done from another
502coroutine (one that doesn't run the event loop).
503
487You can ensure that C<< -wait >> never blocks by setting a callback and 504You can ensure that C<< -recv >> never blocks by setting a callback and
488only calling C<< ->wait >> from within that callback (or at a later 505only calling C<< ->recv >> from within that callback (or at a later
489time). This will work even when the event loop does not support blocking 506time). This will work even when the event loop does not support blocking
490waits otherwise. 507waits otherwise.
508
509=item $bool = $cv->ready
510
511Returns true when the condition is "true", i.e. whether C<send> or
512C<croak> have been called.
513
514=item $cb = $cv->cb ([new callback])
515
516This is a mutator function that returns the callback set and optionally
517replaces it before doing so.
518
519The callback will be called when the condition becomes "true", i.e. when
520C<send> or C<croak> are called. Calling C<recv> inside the callback
521or at any later time is guaranteed not to block.
491 522
492=back 523=back
493 524
494=head1 GLOBAL VARIABLES AND FUNCTIONS 525=head1 GLOBAL VARIABLES AND FUNCTIONS
495 526
503C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 534C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
504AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 535AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
505 536
506The known classes so far are: 537The known classes so far are:
507 538
508 AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
509 AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
510 AnyEvent::Impl::EV based on EV (an interface to libev, best choice). 539 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
511 AnyEvent::Impl::Event based on Event, second best choice. 540 AnyEvent::Impl::Event based on Event, second best choice.
512 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 541 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
513 AnyEvent::Impl::Glib based on Glib, third-best choice. 542 AnyEvent::Impl::Glib based on Glib, third-best choice.
514 AnyEvent::Impl::Tk based on Tk, very bad choice. 543 AnyEvent::Impl::Tk based on Tk, very bad choice.
531Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 560Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
532if necessary. You should only call this function right before you would 561if necessary. You should only call this function right before you would
533have created an AnyEvent watcher anyway, that is, as late as possible at 562have created an AnyEvent watcher anyway, that is, as late as possible at
534runtime. 563runtime.
535 564
565=item $guard = AnyEvent::post_detect { BLOCK }
566
567Arranges for the code block to be executed as soon as the event model is
568autodetected (or immediately if this has already happened).
569
570If called in scalar or list context, then it creates and returns an object
571that automatically removes the callback again when it is destroyed. See
572L<Coro::BDB> for a case where this is useful.
573
574=item @AnyEvent::post_detect
575
576If there are any code references in this array (you can C<push> to it
577before or after loading AnyEvent), then they will called directly after
578the event loop has been chosen.
579
580You should check C<$AnyEvent::MODEL> before adding to this array, though:
581if it contains a true value then the event loop has already been detected,
582and the array will be ignored.
583
584Best use C<AnyEvent::post_detect { BLOCK }> instead.
585
536=back 586=back
537 587
538=head1 WHAT TO DO IN A MODULE 588=head1 WHAT TO DO IN A MODULE
539 589
540As a module author, you should C<use AnyEvent> and call AnyEvent methods 590As a module author, you should C<use AnyEvent> and call AnyEvent methods
543Be careful when you create watchers in the module body - AnyEvent will 593Be careful when you create watchers in the module body - AnyEvent will
544decide which event module to use as soon as the first method is called, so 594decide which event module to use as soon as the first method is called, so
545by calling AnyEvent in your module body you force the user of your module 595by calling AnyEvent in your module body you force the user of your module
546to load the event module first. 596to load the event module first.
547 597
548Never call C<< ->wait >> on a condition variable unless you I<know> that 598Never call C<< ->recv >> on a condition variable unless you I<know> that
549the C<< ->broadcast >> method has been called on it already. This is 599the C<< ->send >> method has been called on it already. This is
550because it will stall the whole program, and the whole point of using 600because it will stall the whole program, and the whole point of using
551events is to stay interactive. 601events is to stay interactive.
552 602
553It is fine, however, to call C<< ->wait >> when the user of your module 603It is fine, however, to call C<< ->recv >> when the user of your module
554requests it (i.e. if you create a http request object ad have a method 604requests it (i.e. if you create a http request object ad have a method
555called C<results> that returns the results, it should call C<< ->wait >> 605called C<results> that returns the results, it should call C<< ->recv >>
556freely, as the user of your module knows what she is doing. always). 606freely, as the user of your module knows what she is doing. always).
557 607
558=head1 WHAT TO DO IN THE MAIN PROGRAM 608=head1 WHAT TO DO IN THE MAIN PROGRAM
559 609
560There will always be a single main program - the only place that should 610There will always be a single main program - the only place that should
594 644
595Provide read and write buffers and manages watchers for reads and writes. 645Provide read and write buffers and manages watchers for reads and writes.
596 646
597=item L<AnyEvent::Socket> 647=item L<AnyEvent::Socket>
598 648
599Provides a means to do non-blocking connects, accepts etc. 649Provides various utility functions for (internet protocol) sockets,
650addresses and name resolution. Also functions to create non-blocking tcp
651connections or tcp servers, with IPv6 and SRV record support and more.
600 652
601=item L<AnyEvent::HTTPD> 653=item L<AnyEvent::HTTPD>
602 654
603Provides a simple web application server framework. 655Provides a simple web application server framework.
604 656
605=item L<AnyEvent::DNS> 657=item L<AnyEvent::DNS>
606 658
607Provides asynchronous DNS resolver capabilities, beyond what 659Provides rich asynchronous DNS resolver capabilities.
608L<AnyEvent::Util> offers.
609 660
610=item L<AnyEvent::FastPing> 661=item L<AnyEvent::FastPing>
611 662
612The fastest ping in the west. 663The fastest ping in the west.
613 664
628 679
629High level API for event-based execution flow control. 680High level API for event-based execution flow control.
630 681
631=item L<Coro> 682=item L<Coro>
632 683
633Has special support for AnyEvent. 684Has special support for AnyEvent via L<Coro::AnyEvent>.
685
686=item L<AnyEvent::AIO>, L<IO::AIO>
687
688Truly asynchronous I/O, should be in the toolbox of every event
689programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
690together.
691
692=item L<AnyEvent::BDB>, L<BDB>
693
694Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
695IO::AIO and AnyEvent together.
634 696
635=item L<IO::Lambda> 697=item L<IO::Lambda>
636 698
637The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 699The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
638
639=item L<IO::AIO>
640
641Truly asynchronous I/O, should be in the toolbox of every event
642programmer. Can be trivially made to use AnyEvent.
643
644=item L<BDB>
645
646Truly asynchronous Berkeley DB access. Can be trivially made to use
647AnyEvent.
648 700
649=back 701=back
650 702
651=cut 703=cut
652 704
655no warnings; 707no warnings;
656use strict; 708use strict;
657 709
658use Carp; 710use Carp;
659 711
660our $VERSION = '3.3'; 712our $VERSION = '4.03';
661our $MODEL; 713our $MODEL;
662 714
663our $AUTOLOAD; 715our $AUTOLOAD;
664our @ISA; 716our @ISA;
665 717
666our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 718our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
667 719
668our @REGISTRY; 720our @REGISTRY;
669 721
722our %PROTOCOL; # (ipv4|ipv6) => (1|2)
723
724{
725 my $idx;
726 $PROTOCOL{$_} = ++$idx
727 for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
728}
729
670my @models = ( 730my @models = (
671 [Coro::EV:: => AnyEvent::Impl::CoroEV::],
672 [Coro::Event:: => AnyEvent::Impl::CoroEvent::],
673 [EV:: => AnyEvent::Impl::EV::], 731 [EV:: => AnyEvent::Impl::EV::],
674 [Event:: => AnyEvent::Impl::Event::], 732 [Event:: => AnyEvent::Impl::Event::],
675 [Tk:: => AnyEvent::Impl::Tk::], 733 [Tk:: => AnyEvent::Impl::Tk::],
676 [Wx:: => AnyEvent::Impl::POE::], 734 [Wx:: => AnyEvent::Impl::POE::],
677 [Prima:: => AnyEvent::Impl::POE::], 735 [Prima:: => AnyEvent::Impl::POE::],
681 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 739 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
682 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 740 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
683 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 741 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
684); 742);
685 743
686our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); 744our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
745
746our @post_detect;
747
748sub post_detect(&) {
749 my ($cb) = @_;
750
751 if ($MODEL) {
752 $cb->();
753
754 1
755 } else {
756 push @post_detect, $cb;
757
758 defined wantarray
759 ? bless \$cb, "AnyEvent::Util::PostDetect"
760 : ()
761 }
762}
763
764sub AnyEvent::Util::PostDetect::DESTROY {
765 @post_detect = grep $_ != ${$_[0]}, @post_detect;
766}
687 767
688sub detect() { 768sub detect() {
689 unless ($MODEL) { 769 unless ($MODEL) {
690 no strict 'refs'; 770 no strict 'refs';
691 771
725 last; 805 last;
726 } 806 }
727 } 807 }
728 808
729 $MODEL 809 $MODEL
730 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; 810 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
731 } 811 }
732 } 812 }
733 813
734 unshift @ISA, $MODEL; 814 unshift @ISA, $MODEL;
735 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 815 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
816
817 (shift @post_detect)->() while @post_detect;
736 } 818 }
737 819
738 $MODEL 820 $MODEL
739} 821}
740 822
750 $class->$func (@_); 832 $class->$func (@_);
751} 833}
752 834
753package AnyEvent::Base; 835package AnyEvent::Base;
754 836
755# default implementation for ->condvar, ->wait, ->broadcast 837# default implementation for ->condvar
756 838
757sub condvar { 839sub condvar {
758 bless \my $flag, "AnyEvent::Base::CondVar" 840 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
759}
760
761sub AnyEvent::Base::CondVar::broadcast {
762 ${$_[0]}++;
763}
764
765sub AnyEvent::Base::CondVar::wait {
766 AnyEvent->one_event while !${$_[0]};
767} 841}
768 842
769# default implementation for ->signal 843# default implementation for ->signal
770 844
771our %SIG_CB; 845our %SIG_CB;
845 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 919 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
846 920
847 undef $CHLD_W unless keys %PID_CB; 921 undef $CHLD_W unless keys %PID_CB;
848} 922}
849 923
924package AnyEvent::CondVar;
925
926our @ISA = AnyEvent::CondVar::Base::;
927
928package AnyEvent::CondVar::Base;
929
930use overload
931 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
932 fallback => 1;
933
934sub _send {
935 # nop
936}
937
938sub send {
939 my $cv = shift;
940 $cv->{_ae_sent} = [@_];
941 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
942 $cv->_send;
943}
944
945sub croak {
946 $_[0]{_ae_croak} = $_[1];
947 $_[0]->send;
948}
949
950sub ready {
951 $_[0]{_ae_sent}
952}
953
954sub _wait {
955 AnyEvent->one_event while !$_[0]{_ae_sent};
956}
957
958sub recv {
959 $_[0]->_wait;
960
961 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
962 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
963}
964
965sub cb {
966 $_[0]{_ae_cb} = $_[1] if @_ > 1;
967 $_[0]{_ae_cb}
968}
969
970sub begin {
971 ++$_[0]{_ae_counter};
972 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
973}
974
975sub end {
976 return if --$_[0]{_ae_counter};
977 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
978}
979
980# undocumented/compatibility with pre-3.4
981*broadcast = \&send;
982*wait = \&_wait;
983
850=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 984=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
851 985
852This is an advanced topic that you do not normally need to use AnyEvent in 986This is an advanced topic that you do not normally need to use AnyEvent in
853a module. This section is only of use to event loop authors who want to 987a module. This section is only of use to event loop authors who want to
854provide AnyEvent compatibility. 988provide AnyEvent compatibility.
910model it chooses. 1044model it chooses.
911 1045
912=item C<PERL_ANYEVENT_MODEL> 1046=item C<PERL_ANYEVENT_MODEL>
913 1047
914This can be used to specify the event model to be used by AnyEvent, before 1048This can be used to specify the event model to be used by AnyEvent, before
915autodetection and -probing kicks in. It must be a string consisting 1049auto detection and -probing kicks in. It must be a string consisting
916entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1050entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
917and the resulting module name is loaded and if the load was successful, 1051and the resulting module name is loaded and if the load was successful,
918used as event model. If it fails to load AnyEvent will proceed with 1052used as event model. If it fails to load AnyEvent will proceed with
919autodetection and -probing. 1053auto detection and -probing.
920 1054
921This functionality might change in future versions. 1055This functionality might change in future versions.
922 1056
923For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1057For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
924could start your program like this: 1058could start your program like this:
925 1059
926 PERL_ANYEVENT_MODEL=Perl perl ... 1060 PERL_ANYEVENT_MODEL=Perl perl ...
1061
1062=item C<PERL_ANYEVENT_PROTOCOLS>
1063
1064Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1065for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1066of auto probing).
1067
1068Must be set to a comma-separated list of protocols or address families,
1069current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1070used, and preference will be given to protocols mentioned earlier in the
1071list.
1072
1073This variable can effectively be used for denial-of-service attacks
1074against local programs (e.g. when setuid), although the impact is likely
1075small, as the program has to handle connection errors already-
1076
1077Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1078but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1079- only support IPv4, never try to resolve or contact IPv6
1080addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1081IPv6, but prefer IPv6 over IPv4.
1082
1083=item C<PERL_ANYEVENT_EDNS0>
1084
1085Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1086for DNS. This extension is generally useful to reduce DNS traffic, but
1087some (broken) firewalls drop such DNS packets, which is why it is off by
1088default.
1089
1090Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1091EDNS0 in its DNS requests.
927 1092
928=back 1093=back
929 1094
930=head1 EXAMPLE PROGRAM 1095=head1 EXAMPLE PROGRAM
931 1096
942 poll => 'r', 1107 poll => 'r',
943 cb => sub { 1108 cb => sub {
944 warn "io event <$_[0]>\n"; # will always output <r> 1109 warn "io event <$_[0]>\n"; # will always output <r>
945 chomp (my $input = <STDIN>); # read a line 1110 chomp (my $input = <STDIN>); # read a line
946 warn "read: $input\n"; # output what has been read 1111 warn "read: $input\n"; # output what has been read
947 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 1112 $cv->send if $input =~ /^q/i; # quit program if /^q/i
948 }, 1113 },
949 ); 1114 );
950 1115
951 my $time_watcher; # can only be used once 1116 my $time_watcher; # can only be used once
952 1117
957 }); 1122 });
958 } 1123 }
959 1124
960 new_timer; # create first timer 1125 new_timer; # create first timer
961 1126
962 $cv->wait; # wait until user enters /^q/i 1127 $cv->recv; # wait until user enters /^q/i
963 1128
964=head1 REAL-WORLD EXAMPLE 1129=head1 REAL-WORLD EXAMPLE
965 1130
966Consider the L<Net::FCP> module. It features (among others) the following 1131Consider the L<Net::FCP> module. It features (among others) the following
967API calls, which are to freenet what HTTP GET requests are to http: 1132API calls, which are to freenet what HTTP GET requests are to http:
1017 syswrite $txn->{fh}, $txn->{request} 1182 syswrite $txn->{fh}, $txn->{request}
1018 or die "connection or write error"; 1183 or die "connection or write error";
1019 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); 1184 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1020 1185
1021Again, C<fh_ready_r> waits till all data has arrived, and then stores the 1186Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1022result and signals any possible waiters that the request ahs finished: 1187result and signals any possible waiters that the request has finished:
1023 1188
1024 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1189 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1025 1190
1026 if (end-of-file or data complete) { 1191 if (end-of-file or data complete) {
1027 $txn->{result} = $txn->{buf}; 1192 $txn->{result} = $txn->{buf};
1028 $txn->{finished}->broadcast; 1193 $txn->{finished}->send;
1029 $txb->{cb}->($txn) of $txn->{cb}; # also call callback 1194 $txb->{cb}->($txn) of $txn->{cb}; # also call callback
1030 } 1195 }
1031 1196
1032The C<result> method, finally, just waits for the finished signal (if the 1197The C<result> method, finally, just waits for the finished signal (if the
1033request was already finished, it doesn't wait, of course, and returns the 1198request was already finished, it doesn't wait, of course, and returns the
1034data: 1199data:
1035 1200
1036 $txn->{finished}->wait; 1201 $txn->{finished}->recv;
1037 return $txn->{result}; 1202 return $txn->{result};
1038 1203
1039The actual code goes further and collects all errors (C<die>s, exceptions) 1204The actual code goes further and collects all errors (C<die>s, exceptions)
1040that occured during request processing. The C<result> method detects 1205that occurred during request processing. The C<result> method detects
1041whether an exception as thrown (it is stored inside the $txn object) 1206whether an exception as thrown (it is stored inside the $txn object)
1042and just throws the exception, which means connection errors and other 1207and just throws the exception, which means connection errors and other
1043problems get reported tot he code that tries to use the result, not in a 1208problems get reported tot he code that tries to use the result, not in a
1044random callback. 1209random callback.
1045 1210
1076 1241
1077 my $quit = AnyEvent->condvar; 1242 my $quit = AnyEvent->condvar;
1078 1243
1079 $fcp->txn_client_get ($url)->cb (sub { 1244 $fcp->txn_client_get ($url)->cb (sub {
1080 ... 1245 ...
1081 $quit->broadcast; 1246 $quit->send;
1082 }); 1247 });
1083 1248
1084 $quit->wait; 1249 $quit->recv;
1085 1250
1086 1251
1087=head1 BENCHMARKS 1252=head1 BENCHMARKS
1088 1253
1089To give you an idea of the performance and overheads that AnyEvent adds 1254To give you an idea of the performance and overheads that AnyEvent adds
1091of various event loops I prepared some benchmarks. 1256of various event loops I prepared some benchmarks.
1092 1257
1093=head2 BENCHMARKING ANYEVENT OVERHEAD 1258=head2 BENCHMARKING ANYEVENT OVERHEAD
1094 1259
1095Here is a benchmark of various supported event models used natively and 1260Here is a benchmark of various supported event models used natively and
1096through anyevent. The benchmark creates a lot of timers (with a zero 1261through AnyEvent. The benchmark creates a lot of timers (with a zero
1097timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1262timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1098which it is), lets them fire exactly once and destroys them again. 1263which it is), lets them fire exactly once and destroys them again.
1099 1264
1100Source code for this benchmark is found as F<eg/bench> in the AnyEvent 1265Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1101distribution. 1266distribution.
1118all watchers, to avoid adding memory overhead. That means closure creation 1283all watchers, to avoid adding memory overhead. That means closure creation
1119and memory usage is not included in the figures. 1284and memory usage is not included in the figures.
1120 1285
1121I<invoke> is the time, in microseconds, used to invoke a simple 1286I<invoke> is the time, in microseconds, used to invoke a simple
1122callback. The callback simply counts down a Perl variable and after it was 1287callback. The callback simply counts down a Perl variable and after it was
1123invoked "watcher" times, it would C<< ->broadcast >> a condvar once to 1288invoked "watcher" times, it would C<< ->send >> a condvar once to
1124signal the end of this phase. 1289signal the end of this phase.
1125 1290
1126I<destroy> is the time, in microseconds, that it takes to destroy a single 1291I<destroy> is the time, in microseconds, that it takes to destroy a single
1127watcher. 1292watcher.
1128 1293
1224 1389
1225=back 1390=back
1226 1391
1227=head2 BENCHMARKING THE LARGE SERVER CASE 1392=head2 BENCHMARKING THE LARGE SERVER CASE
1228 1393
1229This benchmark atcually benchmarks the event loop itself. It works by 1394This benchmark actually benchmarks the event loop itself. It works by
1230creating a number of "servers": each server consists of a socketpair, a 1395creating a number of "servers": each server consists of a socket pair, a
1231timeout watcher that gets reset on activity (but never fires), and an I/O 1396timeout watcher that gets reset on activity (but never fires), and an I/O
1232watcher waiting for input on one side of the socket. Each time the socket 1397watcher waiting for input on one side of the socket. Each time the socket
1233watcher reads a byte it will write that byte to a random other "server". 1398watcher reads a byte it will write that byte to a random other "server".
1234 1399
1235The effect is that there will be a lot of I/O watchers, only part of which 1400The effect is that there will be a lot of I/O watchers, only part of which
1236are active at any one point (so there is a constant number of active 1401are active at any one point (so there is a constant number of active
1237fds for each loop iterstaion, but which fds these are is random). The 1402fds for each loop iteration, but which fds these are is random). The
1238timeout is reset each time something is read because that reflects how 1403timeout is reset each time something is read because that reflects how
1239most timeouts work (and puts extra pressure on the event loops). 1404most timeouts work (and puts extra pressure on the event loops).
1240 1405
1241In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1406In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1242(1%) are active. This mirrors the activity of large servers with many 1407(1%) are active. This mirrors the activity of large servers with many
1243connections, most of which are idle at any one point in time. 1408connections, most of which are idle at any one point in time.
1244 1409
1245Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 1410Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1246distribution. 1411distribution.
1248=head3 Explanation of the columns 1413=head3 Explanation of the columns
1249 1414
1250I<sockets> is the number of sockets, and twice the number of "servers" (as 1415I<sockets> is the number of sockets, and twice the number of "servers" (as
1251each server has a read and write socket end). 1416each server has a read and write socket end).
1252 1417
1253I<create> is the time it takes to create a socketpair (which is 1418I<create> is the time it takes to create a socket pair (which is
1254nontrivial) and two watchers: an I/O watcher and a timeout watcher. 1419nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1255 1420
1256I<request>, the most important value, is the time it takes to handle a 1421I<request>, the most important value, is the time it takes to handle a
1257single "request", that is, reading the token from the pipe and forwarding 1422single "request", that is, reading the token from the pipe and forwarding
1258it to another server. This includes deleting the old timeout and creating 1423it to another server. This includes deleting the old timeout and creating
1331speed most when you have lots of watchers, not when you only have a few of 1496speed most when you have lots of watchers, not when you only have a few of
1332them). 1497them).
1333 1498
1334EV is again fastest. 1499EV is again fastest.
1335 1500
1336Perl again comes second. It is noticably faster than the C-based event 1501Perl again comes second. It is noticeably faster than the C-based event
1337loops Event and Glib, although the difference is too small to really 1502loops Event and Glib, although the difference is too small to really
1338matter. 1503matter.
1339 1504
1340POE also performs much better in this case, but is is still far behind the 1505POE also performs much better in this case, but is is still far behind the
1341others. 1506others.
1374 1539
1375 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1540 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1376 1541
1377 use AnyEvent; 1542 use AnyEvent;
1378 1543
1544Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1545be used to probe what backend is used and gain other information (which is
1546probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1547
1379 1548
1380=head1 SEE ALSO 1549=head1 SEE ALSO
1381 1550
1382Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, 1551Utility functions: L<AnyEvent::Util>.
1383L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, 1552
1553Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1384L<Event::Lib>, L<Qt>, L<POE>. 1554L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1385 1555
1386Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, 1556Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1387L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, 1557L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1388L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, 1558L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1389L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. 1559L<AnyEvent::Impl::POE>.
1390 1560
1561Non-blocking file handles, sockets, TCP clients and
1562servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1563
1564Asynchronous DNS: L<AnyEvent::DNS>.
1565
1566Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1567
1391Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1568Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1392 1569
1393 1570
1394=head1 AUTHOR 1571=head1 AUTHOR
1395 1572
1396 Marc Lehmann <schmorp@schmorp.de> 1573 Marc Lehmann <schmorp@schmorp.de>

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