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1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6and POE are various supported event loops/environments.
6 7
7=head1 SYNOPSIS 8=head1 SYNOPSIS
8 9
9 use AnyEvent; 10 use AnyEvent;
10 11
12 # file descriptor readable
11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... }); 13 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12 14
15 # one-shot or repeating timers
13 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); 16 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... 17 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15 18
16 print AnyEvent->now; # prints current event loop time 19 print AnyEvent->now; # prints current event loop time
17 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. 20 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18 21
22 # POSIX signal
19 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... }); 23 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20 24
25 # child process exit
21 my $w = AnyEvent->child (pid => $pid, cb => sub { 26 my $w = AnyEvent->child (pid => $pid, cb => sub {
22 my ($pid, $status) = @_; 27 my ($pid, $status) = @_;
23 ... 28 ...
24 }); 29 });
30
31 # called when event loop idle (if applicable)
32 my $w = AnyEvent->idle (cb => sub { ... });
25 33
26 my $w = AnyEvent->condvar; # stores whether a condition was flagged 34 my $w = AnyEvent->condvar; # stores whether a condition was flagged
27 $w->send; # wake up current and all future recv's 35 $w->send; # wake up current and all future recv's
28 $w->recv; # enters "main loop" till $condvar gets ->send 36 $w->recv; # enters "main loop" till $condvar gets ->send
29 # use a condvar in callback mode: 37 # use a condvar in callback mode:
32=head1 INTRODUCTION/TUTORIAL 40=head1 INTRODUCTION/TUTORIAL
33 41
34This manpage is mainly a reference manual. If you are interested 42This manpage is mainly a reference manual. If you are interested
35in a tutorial or some gentle introduction, have a look at the 43in a tutorial or some gentle introduction, have a look at the
36L<AnyEvent::Intro> manpage. 44L<AnyEvent::Intro> manpage.
45
46=head1 SUPPORT
47
48There is a mailinglist for discussing all things AnyEvent, and an IRC
49channel, too.
50
51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52Repository>, at L<http://anyevent.schmorp.de>, for more info.
37 53
38=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39 55
40Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41nowadays. So what is different about AnyEvent? 57nowadays. So what is different about AnyEvent?
165my variables are only visible after the statement in which they are 181my variables are only visible after the statement in which they are
166declared. 182declared.
167 183
168=head2 I/O WATCHERS 184=head2 I/O WATCHERS
169 185
186 $w = AnyEvent->io (
187 fh => <filehandle_or_fileno>,
188 poll => <"r" or "w">,
189 cb => <callback>,
190 );
191
170You can create an I/O watcher by calling the C<< AnyEvent->io >> method 192You can create an I/O watcher by calling the C<< AnyEvent->io >> method
171with the following mandatory key-value pairs as arguments: 193with the following mandatory key-value pairs as arguments:
172 194
173C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch 195C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
174for events (AnyEvent might or might not keep a reference to this file 196for events (AnyEvent might or might not keep a reference to this file
175handle). Note that only file handles pointing to things for which 197handle). Note that only file handles pointing to things for which
176non-blocking operation makes sense are allowed. This includes sockets, 198non-blocking operation makes sense are allowed. This includes sockets,
177most character devices, pipes, fifos and so on, but not for example files 199most character devices, pipes, fifos and so on, but not for example files
178or block devices. 200or block devices.
203 undef $w; 225 undef $w;
204 }); 226 });
205 227
206=head2 TIME WATCHERS 228=head2 TIME WATCHERS
207 229
230 $w = AnyEvent->timer (after => <seconds>, cb => <callback>);
231
232 $w = AnyEvent->timer (
233 after => <fractional_seconds>,
234 interval => <fractional_seconds>,
235 cb => <callback>,
236 );
237
208You can create a time watcher by calling the C<< AnyEvent->timer >> 238You can create a time watcher by calling the C<< AnyEvent->timer >>
209method with the following mandatory arguments: 239method with the following mandatory arguments:
210 240
211C<after> specifies after how many seconds (fractional values are 241C<after> specifies after how many seconds (fractional values are
212supported) the callback should be invoked. C<cb> is the callback to invoke 242supported) the callback should be invoked. C<cb> is the callback to invoke
320In either case, if you care (and in most cases, you don't), then you 350In either case, if you care (and in most cases, you don't), then you
321can get whatever behaviour you want with any event loop, by taking the 351can get whatever behaviour you want with any event loop, by taking the
322difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 352difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
323account. 353account.
324 354
355=item AnyEvent->now_update
356
357Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
358the current time for each loop iteration (see the discussion of L<<
359AnyEvent->now >>, above).
360
361When a callback runs for a long time (or when the process sleeps), then
362this "current" time will differ substantially from the real time, which
363might affect timers and time-outs.
364
365When this is the case, you can call this method, which will update the
366event loop's idea of "current time".
367
368Note that updating the time I<might> cause some events to be handled.
369
325=back 370=back
326 371
327=head2 SIGNAL WATCHERS 372=head2 SIGNAL WATCHERS
373
374 $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
328 375
329You can watch for signals using a signal watcher, C<signal> is the signal 376You can watch for signals using a signal watcher, C<signal> is the signal
330I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl 377I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
331callback to be invoked whenever a signal occurs. 378callback to be invoked whenever a signal occurs.
332 379
338invocation, and callback invocation will be synchronous. Synchronous means 385invocation, and callback invocation will be synchronous. Synchronous means
339that it might take a while until the signal gets handled by the process, 386that it might take a while until the signal gets handled by the process,
340but it is guaranteed not to interrupt any other callbacks. 387but it is guaranteed not to interrupt any other callbacks.
341 388
342The main advantage of using these watchers is that you can share a signal 389The main advantage of using these watchers is that you can share a signal
343between multiple watchers. 390between multiple watchers, and AnyEvent will ensure that signals will not
391interrupt your program at bad times.
344 392
345This watcher might use C<%SIG>, so programs overwriting those signals 393This watcher might use C<%SIG> (depending on the event loop used),
346directly will likely not work correctly. 394so programs overwriting those signals directly will likely not work
395correctly.
347 396
348Example: exit on SIGINT 397Example: exit on SIGINT
349 398
350 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 399 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
351 400
401=head3 Signal Races, Delays and Workarounds
402
403Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
404callbacks to signals in a generic way, which is a pity, as you cannot
405do race-free signal handling in perl, requiring C libraries for
406this. AnyEvent will try to do it's best, which means in some cases,
407signals will be delayed. The maximum time a signal might be delayed is
408specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
409variable can be changed only before the first signal watcher is created,
410and should be left alone otherwise. This variable determines how often
411AnyEvent polls for signals (in case a wake-up was missed). Higher values
412will cause fewer spurious wake-ups, which is better for power and CPU
413saving.
414
415All these problems can be avoided by installing the optional
416L<Async::Interrupt> module, which works with most event loops. It will not
417work with inherently broken event loops such as L<Event> or L<Event::Lib>
418(and not with L<POE> currently, as POE does it's own workaround with
419one-second latency). For those, you just have to suffer the delays.
420
352=head2 CHILD PROCESS WATCHERS 421=head2 CHILD PROCESS WATCHERS
353 422
423 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
424
354You can also watch on a child process exit and catch its exit status. 425You can also watch on a child process exit and catch its exit status.
355 426
356The child process is specified by the C<pid> argument (if set to C<0>, it 427The child process is specified by the C<pid> argument (one some backends,
357watches for any child process exit). The watcher will triggered only when 428using C<0> watches for any child process exit, on others this will
358the child process has finished and an exit status is available, not on 429croak). The watcher will be triggered only when the child process has
359any trace events (stopped/continued). 430finished and an exit status is available, not on any trace events
431(stopped/continued).
360 432
361The callback will be called with the pid and exit status (as returned by 433The callback will be called with the pid and exit status (as returned by
362waitpid), so unlike other watcher types, you I<can> rely on child watcher 434waitpid), so unlike other watcher types, you I<can> rely on child watcher
363callback arguments. 435callback arguments.
364 436
369 441
370There is a slight catch to child watchers, however: you usually start them 442There is a slight catch to child watchers, however: you usually start them
371I<after> the child process was created, and this means the process could 443I<after> the child process was created, and this means the process could
372have exited already (and no SIGCHLD will be sent anymore). 444have exited already (and no SIGCHLD will be sent anymore).
373 445
374Not all event models handle this correctly (POE doesn't), but even for 446Not all event models handle this correctly (neither POE nor IO::Async do,
447see their AnyEvent::Impl manpages for details), but even for event models
375event models that I<do> handle this correctly, they usually need to be 448that I<do> handle this correctly, they usually need to be loaded before
376loaded before the process exits (i.e. before you fork in the first place). 449the process exits (i.e. before you fork in the first place). AnyEvent's
450pure perl event loop handles all cases correctly regardless of when you
451start the watcher.
377 452
378This means you cannot create a child watcher as the very first thing in an 453This means you cannot create a child watcher as the very first
379AnyEvent program, you I<have> to create at least one watcher before you 454thing in an AnyEvent program, you I<have> to create at least one
380C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 455watcher before you C<fork> the child (alternatively, you can call
456C<AnyEvent::detect>).
457
458As most event loops do not support waiting for child events, they will be
459emulated by AnyEvent in most cases, in which the latency and race problems
460mentioned in the description of signal watchers apply.
381 461
382Example: fork a process and wait for it 462Example: fork a process and wait for it
383 463
384 my $done = AnyEvent->condvar; 464 my $done = AnyEvent->condvar;
385 465
395 ); 475 );
396 476
397 # do something else, then wait for process exit 477 # do something else, then wait for process exit
398 $done->recv; 478 $done->recv;
399 479
480=head2 IDLE WATCHERS
481
482 $w = AnyEvent->idle (cb => <callback>);
483
484Sometimes there is a need to do something, but it is not so important
485to do it instantly, but only when there is nothing better to do. This
486"nothing better to do" is usually defined to be "no other events need
487attention by the event loop".
488
489Idle watchers ideally get invoked when the event loop has nothing
490better to do, just before it would block the process to wait for new
491events. Instead of blocking, the idle watcher is invoked.
492
493Most event loops unfortunately do not really support idle watchers (only
494EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
495will simply call the callback "from time to time".
496
497Example: read lines from STDIN, but only process them when the
498program is otherwise idle:
499
500 my @lines; # read data
501 my $idle_w;
502 my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
503 push @lines, scalar <STDIN>;
504
505 # start an idle watcher, if not already done
506 $idle_w ||= AnyEvent->idle (cb => sub {
507 # handle only one line, when there are lines left
508 if (my $line = shift @lines) {
509 print "handled when idle: $line";
510 } else {
511 # otherwise disable the idle watcher again
512 undef $idle_w;
513 }
514 });
515 });
516
400=head2 CONDITION VARIABLES 517=head2 CONDITION VARIABLES
518
519 $cv = AnyEvent->condvar;
520
521 $cv->send (<list>);
522 my @res = $cv->recv;
401 523
402If you are familiar with some event loops you will know that all of them 524If you are familiar with some event loops you will know that all of them
403require you to run some blocking "loop", "run" or similar function that 525require you to run some blocking "loop", "run" or similar function that
404will actively watch for new events and call your callbacks. 526will actively watch for new events and call your callbacks.
405 527
406AnyEvent is different, it expects somebody else to run the event loop and 528AnyEvent is slightly different: it expects somebody else to run the event
407will only block when necessary (usually when told by the user). 529loop and will only block when necessary (usually when told by the user).
408 530
409The instrument to do that is called a "condition variable", so called 531The instrument to do that is called a "condition variable", so called
410because they represent a condition that must become true. 532because they represent a condition that must become true.
411 533
534Now is probably a good time to look at the examples further below.
535
412Condition variables can be created by calling the C<< AnyEvent->condvar 536Condition variables can be created by calling the C<< AnyEvent->condvar
413>> method, usually without arguments. The only argument pair allowed is 537>> method, usually without arguments. The only argument pair allowed is
414
415C<cb>, which specifies a callback to be called when the condition variable 538C<cb>, which specifies a callback to be called when the condition variable
416becomes true, with the condition variable as the first argument (but not 539becomes true, with the condition variable as the first argument (but not
417the results). 540the results).
418 541
419After creation, the condition variable is "false" until it becomes "true" 542After creation, the condition variable is "false" until it becomes "true"
424Condition variables are similar to callbacks, except that you can 547Condition variables are similar to callbacks, except that you can
425optionally wait for them. They can also be called merge points - points 548optionally wait for them. They can also be called merge points - points
426in time where multiple outstanding events have been processed. And yet 549in time where multiple outstanding events have been processed. And yet
427another way to call them is transactions - each condition variable can be 550another way to call them is transactions - each condition variable can be
428used to represent a transaction, which finishes at some point and delivers 551used to represent a transaction, which finishes at some point and delivers
429a result. 552a result. And yet some people know them as "futures" - a promise to
553compute/deliver something that you can wait for.
430 554
431Condition variables are very useful to signal that something has finished, 555Condition variables are very useful to signal that something has finished,
432for example, if you write a module that does asynchronous http requests, 556for example, if you write a module that does asynchronous http requests,
433then a condition variable would be the ideal candidate to signal the 557then a condition variable would be the ideal candidate to signal the
434availability of results. The user can either act when the callback is 558availability of results. The user can either act when the callback is
468 after => 1, 592 after => 1,
469 cb => sub { $result_ready->send }, 593 cb => sub { $result_ready->send },
470 ); 594 );
471 595
472 # this "blocks" (while handling events) till the callback 596 # this "blocks" (while handling events) till the callback
473 # calls send 597 # calls -<send
474 $result_ready->recv; 598 $result_ready->recv;
475 599
476Example: wait for a timer, but take advantage of the fact that 600Example: wait for a timer, but take advantage of the fact that condition
477condition variables are also code references. 601variables are also callable directly.
478 602
479 my $done = AnyEvent->condvar; 603 my $done = AnyEvent->condvar;
480 my $delay = AnyEvent->timer (after => 5, cb => $done); 604 my $delay = AnyEvent->timer (after => 5, cb => $done);
481 $done->recv; 605 $done->recv;
482 606
488 612
489 ... 613 ...
490 614
491 my @info = $couchdb->info->recv; 615 my @info = $couchdb->info->recv;
492 616
493And this is how you would just ste a callback to be called whenever the 617And this is how you would just set a callback to be called whenever the
494results are available: 618results are available:
495 619
496 $couchdb->info->cb (sub { 620 $couchdb->info->cb (sub {
497 my @info = $_[0]->recv; 621 my @info = $_[0]->recv;
498 }); 622 });
516immediately from within send. 640immediately from within send.
517 641
518Any arguments passed to the C<send> call will be returned by all 642Any arguments passed to the C<send> call will be returned by all
519future C<< ->recv >> calls. 643future C<< ->recv >> calls.
520 644
521Condition variables are overloaded so one can call them directly 645Condition variables are overloaded so one can call them directly (as if
522(as a code reference). Calling them directly is the same as calling 646they were a code reference). Calling them directly is the same as calling
523C<send>. Note, however, that many C-based event loops do not handle 647C<send>.
524overloading, so as tempting as it may be, passing a condition variable
525instead of a callback does not work. Both the pure perl and EV loops
526support overloading, however, as well as all functions that use perl to
527invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
528example).
529 648
530=item $cv->croak ($error) 649=item $cv->croak ($error)
531 650
532Similar to send, but causes all call's to C<< ->recv >> to invoke 651Similar to send, but causes all call's to C<< ->recv >> to invoke
533C<Carp::croak> with the given error message/object/scalar. 652C<Carp::croak> with the given error message/object/scalar.
534 653
535This can be used to signal any errors to the condition variable 654This can be used to signal any errors to the condition variable
536user/consumer. 655user/consumer. Doing it this way instead of calling C<croak> directly
656delays the error detetcion, but has the overwhelmign advantage that it
657diagnoses the error at the place where the result is expected, and not
658deep in some event clalback without connection to the actual code causing
659the problem.
537 660
538=item $cv->begin ([group callback]) 661=item $cv->begin ([group callback])
539 662
540=item $cv->end 663=item $cv->end
541
542These two methods are EXPERIMENTAL and MIGHT CHANGE.
543 664
544These two methods can be used to combine many transactions/events into 665These two methods can be used to combine many transactions/events into
545one. For example, a function that pings many hosts in parallel might want 666one. For example, a function that pings many hosts in parallel might want
546to use a condition variable for the whole process. 667to use a condition variable for the whole process.
547 668
549C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 670C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
550>>, the (last) callback passed to C<begin> will be executed. That callback 671>>, the (last) callback passed to C<begin> will be executed. That callback
551is I<supposed> to call C<< ->send >>, but that is not required. If no 672is I<supposed> to call C<< ->send >>, but that is not required. If no
552callback was set, C<send> will be called without any arguments. 673callback was set, C<send> will be called without any arguments.
553 674
554Let's clarify this with the ping example: 675You can think of C<< $cv->send >> giving you an OR condition (one call
676sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
677condition (all C<begin> calls must be C<end>'ed before the condvar sends).
678
679Let's start with a simple example: you have two I/O watchers (for example,
680STDOUT and STDERR for a program), and you want to wait for both streams to
681close before activating a condvar:
682
683 my $cv = AnyEvent->condvar;
684
685 $cv->begin; # first watcher
686 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
687 defined sysread $fh1, my $buf, 4096
688 or $cv->end;
689 });
690
691 $cv->begin; # second watcher
692 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
693 defined sysread $fh2, my $buf, 4096
694 or $cv->end;
695 });
696
697 $cv->recv;
698
699This works because for every event source (EOF on file handle), there is
700one call to C<begin>, so the condvar waits for all calls to C<end> before
701sending.
702
703The ping example mentioned above is slightly more complicated, as the
704there are results to be passwd back, and the number of tasks that are
705begung can potentially be zero:
555 706
556 my $cv = AnyEvent->condvar; 707 my $cv = AnyEvent->condvar;
557 708
558 my %result; 709 my %result;
559 $cv->begin (sub { $cv->send (\%result) }); 710 $cv->begin (sub { $cv->send (\%result) });
579loop, which serves two important purposes: first, it sets the callback 730loop, which serves two important purposes: first, it sets the callback
580to be called once the counter reaches C<0>, and second, it ensures that 731to be called once the counter reaches C<0>, and second, it ensures that
581C<send> is called even when C<no> hosts are being pinged (the loop 732C<send> is called even when C<no> hosts are being pinged (the loop
582doesn't execute once). 733doesn't execute once).
583 734
584This is the general pattern when you "fan out" into multiple subrequests: 735This is the general pattern when you "fan out" into multiple (but
585use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 736potentially none) subrequests: use an outer C<begin>/C<end> pair to set
586is called at least once, and then, for each subrequest you start, call 737the callback and ensure C<end> is called at least once, and then, for each
587C<begin> and for each subrequest you finish, call C<end>. 738subrequest you start, call C<begin> and for each subrequest you finish,
739call C<end>.
588 740
589=back 741=back
590 742
591=head3 METHODS FOR CONSUMERS 743=head3 METHODS FOR CONSUMERS
592 744
608function will call C<croak>. 760function will call C<croak>.
609 761
610In list context, all parameters passed to C<send> will be returned, 762In list context, all parameters passed to C<send> will be returned,
611in scalar context only the first one will be returned. 763in scalar context only the first one will be returned.
612 764
765Note that doing a blocking wait in a callback is not supported by any
766event loop, that is, recursive invocation of a blocking C<< ->recv
767>> is not allowed, and the C<recv> call will C<croak> if such a
768condition is detected. This condition can be slightly loosened by using
769L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
770any thread that doesn't run the event loop itself.
771
613Not all event models support a blocking wait - some die in that case 772Not all event models support a blocking wait - some die in that case
614(programs might want to do that to stay interactive), so I<if you are 773(programs might want to do that to stay interactive), so I<if you are
615using this from a module, never require a blocking wait>, but let the 774using this from a module, never require a blocking wait>. Instead, let the
616caller decide whether the call will block or not (for example, by coupling 775caller decide whether the call will block or not (for example, by coupling
617condition variables with some kind of request results and supporting 776condition variables with some kind of request results and supporting
618callbacks so the caller knows that getting the result will not block, 777callbacks so the caller knows that getting the result will not block,
619while still supporting blocking waits if the caller so desires). 778while still supporting blocking waits if the caller so desires).
620 779
621Another reason I<never> to C<< ->recv >> in a module is that you cannot
622sensibly have two C<< ->recv >>'s in parallel, as that would require
623multiple interpreters or coroutines/threads, none of which C<AnyEvent>
624can supply.
625
626The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
627fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
628versions and also integrates coroutines into AnyEvent, making blocking
629C<< ->recv >> calls perfectly safe as long as they are done from another
630coroutine (one that doesn't run the event loop).
631
632You can ensure that C<< -recv >> never blocks by setting a callback and 780You can ensure that C<< -recv >> never blocks by setting a callback and
633only calling C<< ->recv >> from within that callback (or at a later 781only calling C<< ->recv >> from within that callback (or at a later
634time). This will work even when the event loop does not support blocking 782time). This will work even when the event loop does not support blocking
635waits otherwise. 783waits otherwise.
636 784
642=item $cb = $cv->cb ($cb->($cv)) 790=item $cb = $cv->cb ($cb->($cv))
643 791
644This is a mutator function that returns the callback set and optionally 792This is a mutator function that returns the callback set and optionally
645replaces it before doing so. 793replaces it before doing so.
646 794
647The callback will be called when the condition becomes "true", i.e. when 795The callback will be called when the condition becomes (or already was)
648C<send> or C<croak> are called, with the only argument being the condition 796"true", i.e. when C<send> or C<croak> are called (or were called), with
649variable itself. Calling C<recv> inside the callback or at any later time 797the only argument being the condition variable itself. Calling C<recv>
650is guaranteed not to block. 798inside the callback or at any later time is guaranteed not to block.
651 799
652=back 800=back
653 801
802=head1 SUPPORTED EVENT LOOPS/BACKENDS
803
804The available backend classes are (every class has its own manpage):
805
806=over 4
807
808=item Backends that are autoprobed when no other event loop can be found.
809
810EV is the preferred backend when no other event loop seems to be in
811use. If EV is not installed, then AnyEvent will fall back to its own
812pure-perl implementation, which is available everywhere as it comes with
813AnyEvent itself.
814
815 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
816 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
817
818=item Backends that are transparently being picked up when they are used.
819
820These will be used when they are currently loaded when the first watcher
821is created, in which case it is assumed that the application is using
822them. This means that AnyEvent will automatically pick the right backend
823when the main program loads an event module before anything starts to
824create watchers. Nothing special needs to be done by the main program.
825
826 AnyEvent::Impl::Event based on Event, very stable, few glitches.
827 AnyEvent::Impl::Glib based on Glib, slow but very stable.
828 AnyEvent::Impl::Tk based on Tk, very broken.
829 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
830 AnyEvent::Impl::POE based on POE, very slow, some limitations.
831 AnyEvent::Impl::Irssi used when running within irssi.
832
833=item Backends with special needs.
834
835Qt requires the Qt::Application to be instantiated first, but will
836otherwise be picked up automatically. As long as the main program
837instantiates the application before any AnyEvent watchers are created,
838everything should just work.
839
840 AnyEvent::Impl::Qt based on Qt.
841
842Support for IO::Async can only be partial, as it is too broken and
843architecturally limited to even support the AnyEvent API. It also
844is the only event loop that needs the loop to be set explicitly, so
845it can only be used by a main program knowing about AnyEvent. See
846L<AnyEvent::Impl::Async> for the gory details.
847
848 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
849
850=item Event loops that are indirectly supported via other backends.
851
852Some event loops can be supported via other modules:
853
854There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
855
856B<WxWidgets> has no support for watching file handles. However, you can
857use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
858polls 20 times per second, which was considered to be too horrible to even
859consider for AnyEvent.
860
861B<Prima> is not supported as nobody seems to be using it, but it has a POE
862backend, so it can be supported through POE.
863
864AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
865load L<POE> when detecting them, in the hope that POE will pick them up,
866in which case everything will be automatic.
867
868=back
869
654=head1 GLOBAL VARIABLES AND FUNCTIONS 870=head1 GLOBAL VARIABLES AND FUNCTIONS
655 871
872These are not normally required to use AnyEvent, but can be useful to
873write AnyEvent extension modules.
874
656=over 4 875=over 4
657 876
658=item $AnyEvent::MODEL 877=item $AnyEvent::MODEL
659 878
660Contains C<undef> until the first watcher is being created. Then it 879Contains C<undef> until the first watcher is being created, before the
880backend has been autodetected.
881
661contains the event model that is being used, which is the name of the 882Afterwards it contains the event model that is being used, which is the
662Perl class implementing the model. This class is usually one of the 883name of the Perl class implementing the model. This class is usually one
663C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 884of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
664AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 885case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
665 886will be C<urxvt::anyevent>).
666The known classes so far are:
667
668 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
669 AnyEvent::Impl::Event based on Event, second best choice.
670 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
671 AnyEvent::Impl::Glib based on Glib, third-best choice.
672 AnyEvent::Impl::Tk based on Tk, very bad choice.
673 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
674 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
675 AnyEvent::Impl::POE based on POE, not generic enough for full support.
676
677There is no support for WxWidgets, as WxWidgets has no support for
678watching file handles. However, you can use WxWidgets through the
679POE Adaptor, as POE has a Wx backend that simply polls 20 times per
680second, which was considered to be too horrible to even consider for
681AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
682it's adaptor.
683
684AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
685autodetecting them.
686 887
687=item AnyEvent::detect 888=item AnyEvent::detect
688 889
689Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 890Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
690if necessary. You should only call this function right before you would 891if necessary. You should only call this function right before you would
691have created an AnyEvent watcher anyway, that is, as late as possible at 892have created an AnyEvent watcher anyway, that is, as late as possible at
692runtime. 893runtime, and not e.g. while initialising of your module.
894
895If you need to do some initialisation before AnyEvent watchers are
896created, use C<post_detect>.
693 897
694=item $guard = AnyEvent::post_detect { BLOCK } 898=item $guard = AnyEvent::post_detect { BLOCK }
695 899
696Arranges for the code block to be executed as soon as the event model is 900Arranges for the code block to be executed as soon as the event model is
697autodetected (or immediately if this has already happened). 901autodetected (or immediately if this has already happened).
698 902
903The block will be executed I<after> the actual backend has been detected
904(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
905created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
906other initialisations - see the sources of L<AnyEvent::Strict> or
907L<AnyEvent::AIO> to see how this is used.
908
909The most common usage is to create some global watchers, without forcing
910event module detection too early, for example, L<AnyEvent::AIO> creates
911and installs the global L<IO::AIO> watcher in a C<post_detect> block to
912avoid autodetecting the event module at load time.
913
699If called in scalar or list context, then it creates and returns an object 914If called in scalar or list context, then it creates and returns an object
700that automatically removes the callback again when it is destroyed. See 915that automatically removes the callback again when it is destroyed (or
916C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
701L<Coro::BDB> for a case where this is useful. 917a case where this is useful.
918
919Example: Create a watcher for the IO::AIO module and store it in
920C<$WATCHER>. Only do so after the event loop is initialised, though.
921
922 our WATCHER;
923
924 my $guard = AnyEvent::post_detect {
925 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
926 };
927
928 # the ||= is important in case post_detect immediately runs the block,
929 # as to not clobber the newly-created watcher. assigning both watcher and
930 # post_detect guard to the same variable has the advantage of users being
931 # able to just C<undef $WATCHER> if the watcher causes them grief.
932
933 $WATCHER ||= $guard;
702 934
703=item @AnyEvent::post_detect 935=item @AnyEvent::post_detect
704 936
705If there are any code references in this array (you can C<push> to it 937If there are any code references in this array (you can C<push> to it
706before or after loading AnyEvent), then they will called directly after 938before or after loading AnyEvent), then they will called directly after
707the event loop has been chosen. 939the event loop has been chosen.
708 940
709You should check C<$AnyEvent::MODEL> before adding to this array, though: 941You should check C<$AnyEvent::MODEL> before adding to this array, though:
710if it contains a true value then the event loop has already been detected, 942if it is defined then the event loop has already been detected, and the
711and the array will be ignored. 943array will be ignored.
712 944
713Best use C<AnyEvent::post_detect { BLOCK }> instead. 945Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
946it,as it takes care of these details.
947
948This variable is mainly useful for modules that can do something useful
949when AnyEvent is used and thus want to know when it is initialised, but do
950not need to even load it by default. This array provides the means to hook
951into AnyEvent passively, without loading it.
714 952
715=back 953=back
716 954
717=head1 WHAT TO DO IN A MODULE 955=head1 WHAT TO DO IN A MODULE
718 956
773 1011
774 1012
775=head1 OTHER MODULES 1013=head1 OTHER MODULES
776 1014
777The following is a non-exhaustive list of additional modules that use 1015The following is a non-exhaustive list of additional modules that use
778AnyEvent and can therefore be mixed easily with other AnyEvent modules 1016AnyEvent as a client and can therefore be mixed easily with other AnyEvent
779in the same program. Some of the modules come with AnyEvent, some are 1017modules and other event loops in the same program. Some of the modules
780available via CPAN. 1018come with AnyEvent, most are available via CPAN.
781 1019
782=over 4 1020=over 4
783 1021
784=item L<AnyEvent::Util> 1022=item L<AnyEvent::Util>
785 1023
794 1032
795=item L<AnyEvent::Handle> 1033=item L<AnyEvent::Handle>
796 1034
797Provide read and write buffers, manages watchers for reads and writes, 1035Provide read and write buffers, manages watchers for reads and writes,
798supports raw and formatted I/O, I/O queued and fully transparent and 1036supports raw and formatted I/O, I/O queued and fully transparent and
799non-blocking SSL/TLS. 1037non-blocking SSL/TLS (via L<AnyEvent::TLS>.
800 1038
801=item L<AnyEvent::DNS> 1039=item L<AnyEvent::DNS>
802 1040
803Provides rich asynchronous DNS resolver capabilities. 1041Provides rich asynchronous DNS resolver capabilities.
804 1042
832 1070
833=item L<AnyEvent::GPSD> 1071=item L<AnyEvent::GPSD>
834 1072
835A non-blocking interface to gpsd, a daemon delivering GPS information. 1073A non-blocking interface to gpsd, a daemon delivering GPS information.
836 1074
1075=item L<AnyEvent::IRC>
1076
1077AnyEvent based IRC client module family (replacing the older Net::IRC3).
1078
1079=item L<AnyEvent::XMPP>
1080
1081AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1082Net::XMPP2>.
1083
837=item L<AnyEvent::IGS> 1084=item L<AnyEvent::IGS>
838 1085
839A non-blocking interface to the Internet Go Server protocol (used by 1086A non-blocking interface to the Internet Go Server protocol (used by
840L<App::IGS>). 1087L<App::IGS>).
841 1088
842=item L<AnyEvent::IRC>
843
844AnyEvent based IRC client module family (replacing the older Net::IRC3).
845
846=item L<Net::XMPP2>
847
848AnyEvent based XMPP (Jabber protocol) module family.
849
850=item L<Net::FCP> 1089=item L<Net::FCP>
851 1090
852AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1091AnyEvent-based implementation of the Freenet Client Protocol, birthplace
853of AnyEvent. 1092of AnyEvent.
854 1093
858 1097
859=item L<Coro> 1098=item L<Coro>
860 1099
861Has special support for AnyEvent via L<Coro::AnyEvent>. 1100Has special support for AnyEvent via L<Coro::AnyEvent>.
862 1101
863=item L<IO::Lambda>
864
865The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
866
867=back 1102=back
868 1103
869=cut 1104=cut
870 1105
871package AnyEvent; 1106package AnyEvent;
872 1107
1108# basically a tuned-down version of common::sense
1109sub common_sense {
873no warnings; 1110 # no warnings
1111 ${^WARNING_BITS} ^= ${^WARNING_BITS};
874use strict qw(vars subs); 1112 # use strict vars subs
1113 $^H |= 0x00000600;
1114}
875 1115
1116BEGIN { AnyEvent::common_sense }
1117
876use Carp; 1118use Carp ();
877 1119
878our $VERSION = 4.35; 1120our $VERSION = '5.0';
879our $MODEL; 1121our $MODEL;
880 1122
881our $AUTOLOAD; 1123our $AUTOLOAD;
882our @ISA; 1124our @ISA;
883 1125
884our @REGISTRY; 1126our @REGISTRY;
885 1127
886our $WIN32; 1128our $WIN32;
887 1129
1130our $VERBOSE;
1131
888BEGIN { 1132BEGIN {
889 my $win32 = ! ! ($^O =~ /mswin32/i); 1133 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
890 eval "sub WIN32(){ $win32 }"; 1134 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
891}
892 1135
1136 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1137 if ${^TAINT};
1138
893our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1139 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1140
1141}
1142
1143our $MAX_SIGNAL_LATENCY = 10;
894 1144
895our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1145our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
896 1146
897{ 1147{
898 my $idx; 1148 my $idx;
900 for reverse split /\s*,\s*/, 1150 for reverse split /\s*,\s*/,
901 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1151 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
902} 1152}
903 1153
904my @models = ( 1154my @models = (
905 [EV:: => AnyEvent::Impl::EV::], 1155 [EV:: => AnyEvent::Impl::EV:: , 1],
906 [Event:: => AnyEvent::Impl::Event::],
907 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1156 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
908 # everything below here will not be autoprobed 1157 # everything below here will not (normally) be autoprobed
909 # as the pureperl backend should work everywhere 1158 # as the pureperl backend should work everywhere
910 # and is usually faster 1159 # and is usually faster
1160 [Event:: => AnyEvent::Impl::Event::, 1],
1161 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1162 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1163 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
911 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1164 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
912 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
913 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
914 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1165 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
915 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1166 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
916 [Wx:: => AnyEvent::Impl::POE::], 1167 [Wx:: => AnyEvent::Impl::POE::],
917 [Prima:: => AnyEvent::Impl::POE::], 1168 [Prima:: => AnyEvent::Impl::POE::],
1169 # IO::Async is just too broken - we would need workarounds for its
1170 # byzantine signal and broken child handling, among others.
1171 # IO::Async is rather hard to detect, as it doesn't have any
1172 # obvious default class.
1173 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1174 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1175 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1176 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
918); 1177);
919 1178
920our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 1179our %method = map +($_ => 1),
1180 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
921 1181
922our @post_detect; 1182our @post_detect;
923 1183
924sub post_detect(&) { 1184sub post_detect(&) {
925 my ($cb) = @_; 1185 my ($cb) = @_;
926 1186
927 if ($MODEL) { 1187 if ($MODEL) {
928 $cb->(); 1188 $cb->();
929 1189
930 1 1190 undef
931 } else { 1191 } else {
932 push @post_detect, $cb; 1192 push @post_detect, $cb;
933 1193
934 defined wantarray 1194 defined wantarray
935 ? bless \$cb, "AnyEvent::Util::PostDetect" 1195 ? bless \$cb, "AnyEvent::Util::postdetect"
936 : () 1196 : ()
937 } 1197 }
938} 1198}
939 1199
940sub AnyEvent::Util::PostDetect::DESTROY { 1200sub AnyEvent::Util::postdetect::DESTROY {
941 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1201 @post_detect = grep $_ != ${$_[0]}, @post_detect;
942} 1202}
943 1203
944sub detect() { 1204sub detect() {
945 unless ($MODEL) { 1205 unless ($MODEL) {
946 no strict 'refs';
947 local $SIG{__DIE__}; 1206 local $SIG{__DIE__};
948 1207
949 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1208 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
950 my $model = "AnyEvent::Impl::$1"; 1209 my $model = "AnyEvent::Impl::$1";
951 if (eval "require $model") { 1210 if (eval "require $model") {
952 $MODEL = $model; 1211 $MODEL = $model;
953 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1212 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
954 } else { 1213 } else {
955 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1214 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
956 } 1215 }
957 } 1216 }
958 1217
959 # check for already loaded models 1218 # check for already loaded models
960 unless ($MODEL) { 1219 unless ($MODEL) {
961 for (@REGISTRY, @models) { 1220 for (@REGISTRY, @models) {
962 my ($package, $model) = @$_; 1221 my ($package, $model) = @$_;
963 if (${"$package\::VERSION"} > 0) { 1222 if (${"$package\::VERSION"} > 0) {
964 if (eval "require $model") { 1223 if (eval "require $model") {
965 $MODEL = $model; 1224 $MODEL = $model;
966 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1225 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
967 last; 1226 last;
968 } 1227 }
969 } 1228 }
970 } 1229 }
971 1230
972 unless ($MODEL) { 1231 unless ($MODEL) {
973 # try to load a model 1232 # try to autoload a model
974
975 for (@REGISTRY, @models) { 1233 for (@REGISTRY, @models) {
976 my ($package, $model) = @$_; 1234 my ($package, $model, $autoload) = @$_;
1235 if (
1236 $autoload
977 if (eval "require $package" 1237 and eval "require $package"
978 and ${"$package\::VERSION"} > 0 1238 and ${"$package\::VERSION"} > 0
979 and eval "require $model") { 1239 and eval "require $model"
1240 ) {
980 $MODEL = $model; 1241 $MODEL = $model;
981 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1242 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
982 last; 1243 last;
983 } 1244 }
984 } 1245 }
985 1246
986 $MODEL 1247 $MODEL
987 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1248 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
988 } 1249 }
989 } 1250 }
990 1251
991 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1252 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
992 1253
1002 1263
1003sub AUTOLOAD { 1264sub AUTOLOAD {
1004 (my $func = $AUTOLOAD) =~ s/.*://; 1265 (my $func = $AUTOLOAD) =~ s/.*://;
1005 1266
1006 $method{$func} 1267 $method{$func}
1007 or croak "$func: not a valid method for AnyEvent objects"; 1268 or Carp::croak "$func: not a valid method for AnyEvent objects";
1008 1269
1009 detect unless $MODEL; 1270 detect unless $MODEL;
1010 1271
1011 my $class = shift; 1272 my $class = shift;
1012 $class->$func (@_); 1273 $class->$func (@_);
1013} 1274}
1014 1275
1015# utility function to dup a filehandle. this is used by many backends 1276# utility function to dup a filehandle. this is used by many backends
1016# to support binding more than one watcher per filehandle (they usually 1277# to support binding more than one watcher per filehandle (they usually
1017# allow only one watcher per fd, so we dup it to get a different one). 1278# allow only one watcher per fd, so we dup it to get a different one).
1018sub _dupfh($$$$) { 1279sub _dupfh($$;$$) {
1019 my ($poll, $fh, $r, $w) = @_; 1280 my ($poll, $fh, $r, $w) = @_;
1020 1281
1021 # cygwin requires the fh mode to be matching, unix doesn't 1282 # cygwin requires the fh mode to be matching, unix doesn't
1022 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1283 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1023 : $poll eq "w" ? ($w, ">")
1024 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1025 1284
1026 open my $fh2, "$mode&" . fileno $fh 1285 open my $fh2, $mode, $fh
1027 or die "cannot dup() filehandle: $!"; 1286 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1028 1287
1029 # we assume CLOEXEC is already set by perl in all important cases 1288 # we assume CLOEXEC is already set by perl in all important cases
1030 1289
1031 ($fh2, $rw) 1290 ($fh2, $rw)
1032} 1291}
1033 1292
1293=head1 SIMPLIFIED AE API
1294
1295Starting with version 5.0, AnyEvent officially supports a second, much
1296simpler, API that is designed to reduce the calling, typing and memory
1297overhead.
1298
1299See the L<AE> manpage for details.
1300
1301=cut
1302
1303package AE;
1304
1305our $VERSION = $AnyEvent::VERSION;
1306
1307sub io($$$) {
1308 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1309}
1310
1311sub timer($$$) {
1312 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1313}
1314
1315sub signal($$) {
1316 AnyEvent->signal (signal => $_[0], cb => $_[1])
1317}
1318
1319sub child($$) {
1320 AnyEvent->child (pid => $_[0], cb => $_[1])
1321}
1322
1323sub idle($) {
1324 AnyEvent->idle (cb => $_[0])
1325}
1326
1327sub cv(;&) {
1328 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1329}
1330
1331sub now() {
1332 AnyEvent->now
1333}
1334
1335sub now_update() {
1336 AnyEvent->now_update
1337}
1338
1339sub time() {
1340 AnyEvent->time
1341}
1342
1034package AnyEvent::Base; 1343package AnyEvent::Base;
1035 1344
1036# default implementation for now and time 1345# default implementations for many methods
1037 1346
1038BEGIN { 1347sub _time {
1348 # probe for availability of Time::HiRes
1039 if (eval "use Time::HiRes (); time (); 1") { 1349 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1350 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1040 *_time = \&Time::HiRes::time; 1351 *_time = \&Time::HiRes::time;
1041 # if (eval "use POSIX (); (POSIX::times())... 1352 # if (eval "use POSIX (); (POSIX::times())...
1042 } else { 1353 } else {
1354 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1043 *_time = sub { time }; # epic fail 1355 *_time = sub { time }; # epic fail
1044 } 1356 }
1357
1358 &_time
1045} 1359}
1046 1360
1047sub time { _time } 1361sub time { _time }
1048sub now { _time } 1362sub now { _time }
1363sub now_update { }
1049 1364
1050# default implementation for ->condvar 1365# default implementation for ->condvar
1051 1366
1052sub condvar { 1367sub condvar {
1053 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1368 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1054} 1369}
1055 1370
1056# default implementation for ->signal 1371# default implementation for ->signal
1057 1372
1373our $HAVE_ASYNC_INTERRUPT;
1374
1375sub _have_async_interrupt() {
1376 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1377 && eval "use Async::Interrupt 1.0 (); 1")
1378 unless defined $HAVE_ASYNC_INTERRUPT;
1379
1380 $HAVE_ASYNC_INTERRUPT
1381}
1382
1058our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1383our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1384our (%SIG_ASY, %SIG_ASY_W);
1385our ($SIG_COUNT, $SIG_TW);
1059 1386
1060sub _signal_exec { 1387sub _signal_exec {
1388 $HAVE_ASYNC_INTERRUPT
1389 ? $SIGPIPE_R->drain
1061 sysread $SIGPIPE_R, my $dummy, 4; 1390 : sysread $SIGPIPE_R, my $dummy, 9;
1062 1391
1063 while (%SIG_EV) { 1392 while (%SIG_EV) {
1064 for (keys %SIG_EV) { 1393 for (keys %SIG_EV) {
1065 delete $SIG_EV{$_}; 1394 delete $SIG_EV{$_};
1066 $_->() for values %{ $SIG_CB{$_} || {} }; 1395 $_->() for values %{ $SIG_CB{$_} || {} };
1067 } 1396 }
1068 } 1397 }
1069} 1398}
1070 1399
1400# install a dummy wakeup watcher to reduce signal catching latency
1401sub _sig_add() {
1402 unless ($SIG_COUNT++) {
1403 # try to align timer on a full-second boundary, if possible
1404 my $NOW = AE::now;
1405
1406 $SIG_TW = AE::timer
1407 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1408 $MAX_SIGNAL_LATENCY,
1409 sub { } # just for the PERL_ASYNC_CHECK
1410 ;
1411 }
1412}
1413
1414sub _sig_del {
1415 undef $SIG_TW
1416 unless --$SIG_COUNT;
1417}
1418
1419our $_sig_name_init; $_sig_name_init = sub {
1420 eval q{ # poor man's autoloading
1421 undef $_sig_name_init;
1422
1423 if (_have_async_interrupt) {
1424 *sig2num = \&Async::Interrupt::sig2num;
1425 *sig2name = \&Async::Interrupt::sig2name;
1426 } else {
1427 require Config;
1428
1429 my %signame2num;
1430 @signame2num{ split ' ', $Config::Config{sig_name} }
1431 = split ' ', $Config::Config{sig_num};
1432
1433 my @signum2name;
1434 @signum2name[values %signame2num] = keys %signame2num;
1435
1436 *sig2num = sub($) {
1437 $_[0] > 0 ? shift : $signame2num{+shift}
1438 };
1439 *sig2name = sub ($) {
1440 $_[0] > 0 ? $signum2name[+shift] : shift
1441 };
1442 }
1443 };
1444 die if $@;
1445};
1446
1447sub sig2num ($) { &$_sig_name_init; &sig2num }
1448sub sig2name($) { &$_sig_name_init; &sig2name }
1449
1071sub signal { 1450sub signal {
1072 my (undef, %arg) = @_; 1451 eval q{ # poor man's autoloading {}
1452 # probe for availability of Async::Interrupt
1453 if (_have_async_interrupt) {
1454 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1073 1455
1074 unless ($SIGPIPE_R) { 1456 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1075 require Fcntl; 1457 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1076 1458
1077 if (AnyEvent::WIN32) {
1078 require AnyEvent::Util;
1079
1080 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1081 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1082 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1083 } else { 1459 } else {
1460 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1461
1462 require Fcntl;
1463
1464 if (AnyEvent::WIN32) {
1465 require AnyEvent::Util;
1466
1467 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1468 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1469 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1470 } else {
1084 pipe $SIGPIPE_R, $SIGPIPE_W; 1471 pipe $SIGPIPE_R, $SIGPIPE_W;
1085 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1472 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1086 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case 1473 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1474
1475 # not strictly required, as $^F is normally 2, but let's make sure...
1476 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1477 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1478 }
1479
1480 $SIGPIPE_R
1481 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1482
1483 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1087 } 1484 }
1088 1485
1089 $SIGPIPE_R 1486 *signal = sub {
1090 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1487 my (undef, %arg) = @_;
1091 1488
1092 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1093 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094
1095 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1096 }
1097
1098 my $signal = uc $arg{signal} 1489 my $signal = uc $arg{signal}
1099 or Carp::croak "required option 'signal' is missing"; 1490 or Carp::croak "required option 'signal' is missing";
1100 1491
1492 if ($HAVE_ASYNC_INTERRUPT) {
1493 # async::interrupt
1494
1495 $signal = sig2num $signal;
1101 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1496 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1497
1498 $SIG_ASY{$signal} ||= new Async::Interrupt
1499 cb => sub { undef $SIG_EV{$signal} },
1500 signal => $signal,
1501 pipe => [$SIGPIPE_R->filenos],
1502 pipe_autodrain => 0,
1503 ;
1504
1505 } else {
1506 # pure perl
1507
1508 # AE::Util has been loaded in signal
1509 $signal = sig2name $signal;
1510 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1511
1102 $SIG{$signal} ||= sub { 1512 $SIG{$signal} ||= sub {
1513 local $!;
1103 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1514 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1104 undef $SIG_EV{$signal}; 1515 undef $SIG_EV{$signal};
1516 };
1517
1518 # can't do signal processing without introducing races in pure perl,
1519 # so limit the signal latency.
1520 _sig_add;
1521 }
1522
1523 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1524 };
1525
1526 *AnyEvent::Base::signal::DESTROY = sub {
1527 my ($signal, $cb) = @{$_[0]};
1528
1529 _sig_del;
1530
1531 delete $SIG_CB{$signal}{$cb};
1532
1533 $HAVE_ASYNC_INTERRUPT
1534 ? delete $SIG_ASY{$signal}
1535 : # delete doesn't work with older perls - they then
1536 # print weird messages, or just unconditionally exit
1537 # instead of getting the default action.
1538 undef $SIG{$signal}
1539 unless keys %{ $SIG_CB{$signal} };
1540 };
1105 }; 1541 };
1106 1542 die if $@;
1107 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1543 &signal
1108}
1109
1110sub AnyEvent::Base::Signal::DESTROY {
1111 my ($signal, $cb) = @{$_[0]};
1112
1113 delete $SIG_CB{$signal}{$cb};
1114
1115 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1116} 1544}
1117 1545
1118# default implementation for ->child 1546# default implementation for ->child
1119 1547
1120our %PID_CB; 1548our %PID_CB;
1121our $CHLD_W; 1549our $CHLD_W;
1122our $CHLD_DELAY_W; 1550our $CHLD_DELAY_W;
1123our $PID_IDLE;
1124our $WNOHANG; 1551our $WNOHANG;
1125 1552
1126sub _child_wait { 1553sub _emit_childstatus($$) {
1127 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1554 my (undef, $rpid, $rstatus) = @_;
1555
1556 $_->($rpid, $rstatus)
1128 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1557 for values %{ $PID_CB{$rpid} || {} },
1129 (values %{ $PID_CB{0} || {} }); 1558 values %{ $PID_CB{0} || {} };
1130 }
1131
1132 undef $PID_IDLE;
1133} 1559}
1134 1560
1135sub _sigchld { 1561sub _sigchld {
1136 # make sure we deliver these changes "synchronous" with the event loop. 1562 my $pid;
1137 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { 1563
1138 undef $CHLD_DELAY_W; 1564 AnyEvent->_emit_childstatus ($pid, $?)
1139 &_child_wait; 1565 while ($pid = waitpid -1, $WNOHANG) > 0;
1140 });
1141} 1566}
1142 1567
1143sub child { 1568sub child {
1144 my (undef, %arg) = @_; 1569 my (undef, %arg) = @_;
1145 1570
1146 defined (my $pid = $arg{pid} + 0) 1571 defined (my $pid = $arg{pid} + 0)
1147 or Carp::croak "required option 'pid' is missing"; 1572 or Carp::croak "required option 'pid' is missing";
1148 1573
1149 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1574 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1150 1575
1151 unless ($WNOHANG) { 1576 # WNOHANG is almost cetrainly 1 everywhere
1577 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1578 ? 1
1152 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1579 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1153 }
1154 1580
1155 unless ($CHLD_W) { 1581 unless ($CHLD_W) {
1156 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1582 $CHLD_W = AE::signal CHLD => \&_sigchld;
1157 # child could be a zombie already, so make at least one round 1583 # child could be a zombie already, so make at least one round
1158 &_sigchld; 1584 &_sigchld;
1159 } 1585 }
1160 1586
1161 bless [$pid, $arg{cb}], "AnyEvent::Base::Child" 1587 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1162} 1588}
1163 1589
1164sub AnyEvent::Base::Child::DESTROY { 1590sub AnyEvent::Base::child::DESTROY {
1165 my ($pid, $cb) = @{$_[0]}; 1591 my ($pid, $cb) = @{$_[0]};
1166 1592
1167 delete $PID_CB{$pid}{$cb}; 1593 delete $PID_CB{$pid}{$cb};
1168 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1594 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1169 1595
1170 undef $CHLD_W unless keys %PID_CB; 1596 undef $CHLD_W unless keys %PID_CB;
1171} 1597}
1172 1598
1599# idle emulation is done by simply using a timer, regardless
1600# of whether the process is idle or not, and not letting
1601# the callback use more than 50% of the time.
1602sub idle {
1603 my (undef, %arg) = @_;
1604
1605 my ($cb, $w, $rcb) = $arg{cb};
1606
1607 $rcb = sub {
1608 if ($cb) {
1609 $w = _time;
1610 &$cb;
1611 $w = _time - $w;
1612
1613 # never use more then 50% of the time for the idle watcher,
1614 # within some limits
1615 $w = 0.0001 if $w < 0.0001;
1616 $w = 5 if $w > 5;
1617
1618 $w = AE::timer $w, 0, $rcb;
1619 } else {
1620 # clean up...
1621 undef $w;
1622 undef $rcb;
1623 }
1624 };
1625
1626 $w = AE::timer 0.05, 0, $rcb;
1627
1628 bless \\$cb, "AnyEvent::Base::idle"
1629}
1630
1631sub AnyEvent::Base::idle::DESTROY {
1632 undef $${$_[0]};
1633}
1634
1173package AnyEvent::CondVar; 1635package AnyEvent::CondVar;
1174 1636
1175our @ISA = AnyEvent::CondVar::Base::; 1637our @ISA = AnyEvent::CondVar::Base::;
1176 1638
1177package AnyEvent::CondVar::Base; 1639package AnyEvent::CondVar::Base;
1178 1640
1179use overload 1641#use overload
1180 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1642# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1181 fallback => 1; 1643# fallback => 1;
1644
1645# save 300+ kilobytes by dirtily hardcoding overloading
1646${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1647*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1648*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1649${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1650
1651our $WAITING;
1182 1652
1183sub _send { 1653sub _send {
1184 # nop 1654 # nop
1185} 1655}
1186 1656
1199sub ready { 1669sub ready {
1200 $_[0]{_ae_sent} 1670 $_[0]{_ae_sent}
1201} 1671}
1202 1672
1203sub _wait { 1673sub _wait {
1674 $WAITING
1675 and !$_[0]{_ae_sent}
1676 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1677
1678 local $WAITING = 1;
1204 AnyEvent->one_event while !$_[0]{_ae_sent}; 1679 AnyEvent->one_event while !$_[0]{_ae_sent};
1205} 1680}
1206 1681
1207sub recv { 1682sub recv {
1208 $_[0]->_wait; 1683 $_[0]->_wait;
1210 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1685 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1211 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1686 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1212} 1687}
1213 1688
1214sub cb { 1689sub cb {
1215 $_[0]{_ae_cb} = $_[1] if @_ > 1; 1690 my $cv = shift;
1691
1692 @_
1693 and $cv->{_ae_cb} = shift
1694 and $cv->{_ae_sent}
1695 and (delete $cv->{_ae_cb})->($cv);
1696
1216 $_[0]{_ae_cb} 1697 $cv->{_ae_cb}
1217} 1698}
1218 1699
1219sub begin { 1700sub begin {
1220 ++$_[0]{_ae_counter}; 1701 ++$_[0]{_ae_counter};
1221 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1702 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1249so on. 1730so on.
1250 1731
1251=head1 ENVIRONMENT VARIABLES 1732=head1 ENVIRONMENT VARIABLES
1252 1733
1253The following environment variables are used by this module or its 1734The following environment variables are used by this module or its
1254submodules: 1735submodules.
1736
1737Note that AnyEvent will remove I<all> environment variables starting with
1738C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
1739enabled.
1255 1740
1256=over 4 1741=over 4
1257 1742
1258=item C<PERL_ANYEVENT_VERBOSE> 1743=item C<PERL_ANYEVENT_VERBOSE>
1259 1744
1266C<PERL_ANYEVENT_MODEL>. 1751C<PERL_ANYEVENT_MODEL>.
1267 1752
1268When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1753When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1269model it chooses. 1754model it chooses.
1270 1755
1756When set to C<8> or higher, then AnyEvent will report extra information on
1757which optional modules it loads and how it implements certain features.
1758
1271=item C<PERL_ANYEVENT_STRICT> 1759=item C<PERL_ANYEVENT_STRICT>
1272 1760
1273AnyEvent does not do much argument checking by default, as thorough 1761AnyEvent does not do much argument checking by default, as thorough
1274argument checking is very costly. Setting this variable to a true value 1762argument checking is very costly. Setting this variable to a true value
1275will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1763will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1276check the arguments passed to most method calls. If it finds any problems 1764check the arguments passed to most method calls. If it finds any problems,
1277it will croak. 1765it will croak.
1278 1766
1279In other words, enables "strict" mode. 1767In other words, enables "strict" mode.
1280 1768
1281Unlike C<use strict>, it is definitely recommended ot keep it off in 1769Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1282production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1770>>, it is definitely recommended to keep it off in production. Keeping
1283developing programs can be very useful, however. 1771C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1772can be very useful, however.
1284 1773
1285=item C<PERL_ANYEVENT_MODEL> 1774=item C<PERL_ANYEVENT_MODEL>
1286 1775
1287This can be used to specify the event model to be used by AnyEvent, before 1776This can be used to specify the event model to be used by AnyEvent, before
1288auto detection and -probing kicks in. It must be a string consisting 1777auto detection and -probing kicks in. It must be a string consisting
1331 1820
1332=item C<PERL_ANYEVENT_MAX_FORKS> 1821=item C<PERL_ANYEVENT_MAX_FORKS>
1333 1822
1334The maximum number of child processes that C<AnyEvent::Util::fork_call> 1823The maximum number of child processes that C<AnyEvent::Util::fork_call>
1335will create in parallel. 1824will create in parallel.
1825
1826=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1827
1828The default value for the C<max_outstanding> parameter for the default DNS
1829resolver - this is the maximum number of parallel DNS requests that are
1830sent to the DNS server.
1831
1832=item C<PERL_ANYEVENT_RESOLV_CONF>
1833
1834The file to use instead of F</etc/resolv.conf> (or OS-specific
1835configuration) in the default resolver. When set to the empty string, no
1836default config will be used.
1837
1838=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1839
1840When neither C<ca_file> nor C<ca_path> was specified during
1841L<AnyEvent::TLS> context creation, and either of these environment
1842variables exist, they will be used to specify CA certificate locations
1843instead of a system-dependent default.
1844
1845=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1846
1847When these are set to C<1>, then the respective modules are not
1848loaded. Mostly good for testing AnyEvent itself.
1336 1849
1337=back 1850=back
1338 1851
1339=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1852=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1340 1853
1548through AnyEvent. The benchmark creates a lot of timers (with a zero 2061through AnyEvent. The benchmark creates a lot of timers (with a zero
1549timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2062timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1550which it is), lets them fire exactly once and destroys them again. 2063which it is), lets them fire exactly once and destroys them again.
1551 2064
1552Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2065Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1553distribution. 2066distribution. It uses the L<AE> interface, which makes a real difference
2067for the EV and Perl backends only.
1554 2068
1555=head3 Explanation of the columns 2069=head3 Explanation of the columns
1556 2070
1557I<watcher> is the number of event watchers created/destroyed. Since 2071I<watcher> is the number of event watchers created/destroyed. Since
1558different event models feature vastly different performances, each event 2072different event models feature vastly different performances, each event
1579watcher. 2093watcher.
1580 2094
1581=head3 Results 2095=head3 Results
1582 2096
1583 name watchers bytes create invoke destroy comment 2097 name watchers bytes create invoke destroy comment
1584 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2098 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1585 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2099 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1586 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2100 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1587 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2101 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1588 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2102 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1589 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2103 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2104 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2105 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1590 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2106 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1591 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2107 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1592 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2108 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1593 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2109 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1594 2110
1595=head3 Discussion 2111=head3 Discussion
1596 2112
1597The benchmark does I<not> measure scalability of the event loop very 2113The benchmark does I<not> measure scalability of the event loop very
1598well. For example, a select-based event loop (such as the pure perl one) 2114well. For example, a select-based event loop (such as the pure perl one)
1610benchmark machine, handling an event takes roughly 1600 CPU cycles with 2126benchmark machine, handling an event takes roughly 1600 CPU cycles with
1611EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2127EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1612cycles with POE. 2128cycles with POE.
1613 2129
1614C<EV> is the sole leader regarding speed and memory use, which are both 2130C<EV> is the sole leader regarding speed and memory use, which are both
1615maximal/minimal, respectively. Even when going through AnyEvent, it uses 2131maximal/minimal, respectively. When using the L<AE> API there is zero
2132overhead (when going through the AnyEvent API create is about 5-6 times
2133slower, with other times being equal, so still uses far less memory than
1616far less memory than any other event loop and is still faster than Event 2134any other event loop and is still faster than Event natively).
1617natively.
1618 2135
1619The pure perl implementation is hit in a few sweet spots (both the 2136The pure perl implementation is hit in a few sweet spots (both the
1620constant timeout and the use of a single fd hit optimisations in the perl 2137constant timeout and the use of a single fd hit optimisations in the perl
1621interpreter and the backend itself). Nevertheless this shows that it 2138interpreter and the backend itself). Nevertheless this shows that it
1622adds very little overhead in itself. Like any select-based backend its 2139adds very little overhead in itself. Like any select-based backend its
1623performance becomes really bad with lots of file descriptors (and few of 2140performance becomes really bad with lots of file descriptors (and few of
1624them active), of course, but this was not subject of this benchmark. 2141them active), of course, but this was not subject of this benchmark.
1625 2142
1626The C<Event> module has a relatively high setup and callback invocation 2143The C<Event> module has a relatively high setup and callback invocation
1627cost, but overall scores in on the third place. 2144cost, but overall scores in on the third place.
2145
2146C<IO::Async> performs admirably well, about on par with C<Event>, even
2147when using its pure perl backend.
1628 2148
1629C<Glib>'s memory usage is quite a bit higher, but it features a 2149C<Glib>'s memory usage is quite a bit higher, but it features a
1630faster callback invocation and overall ends up in the same class as 2150faster callback invocation and overall ends up in the same class as
1631C<Event>. However, Glib scales extremely badly, doubling the number of 2151C<Event>. However, Glib scales extremely badly, doubling the number of
1632watchers increases the processing time by more than a factor of four, 2152watchers increases the processing time by more than a factor of four,
1693In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2213In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1694(1%) are active. This mirrors the activity of large servers with many 2214(1%) are active. This mirrors the activity of large servers with many
1695connections, most of which are idle at any one point in time. 2215connections, most of which are idle at any one point in time.
1696 2216
1697Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2217Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1698distribution. 2218distribution. It uses the L<AE> interface, which makes a real difference
2219for the EV and Perl backends only.
1699 2220
1700=head3 Explanation of the columns 2221=head3 Explanation of the columns
1701 2222
1702I<sockets> is the number of sockets, and twice the number of "servers" (as 2223I<sockets> is the number of sockets, and twice the number of "servers" (as
1703each server has a read and write socket end). 2224each server has a read and write socket end).
1710it to another server. This includes deleting the old timeout and creating 2231it to another server. This includes deleting the old timeout and creating
1711a new one that moves the timeout into the future. 2232a new one that moves the timeout into the future.
1712 2233
1713=head3 Results 2234=head3 Results
1714 2235
1715 name sockets create request 2236 name sockets create request
1716 EV 20000 69.01 11.16 2237 EV 20000 62.66 7.99
1717 Perl 20000 73.32 35.87 2238 Perl 20000 68.32 32.64
1718 Event 20000 212.62 257.32 2239 IOAsync 20000 174.06 101.15 epoll
1719 Glib 20000 651.16 1896.30 2240 IOAsync 20000 174.67 610.84 poll
2241 Event 20000 202.69 242.91
2242 Glib 20000 557.01 1689.52
1720 POE 20000 349.67 12317.24 uses POE::Loop::Event 2243 POE 20000 341.54 12086.32 uses POE::Loop::Event
1721 2244
1722=head3 Discussion 2245=head3 Discussion
1723 2246
1724This benchmark I<does> measure scalability and overall performance of the 2247This benchmark I<does> measure scalability and overall performance of the
1725particular event loop. 2248particular event loop.
1727EV is again fastest. Since it is using epoll on my system, the setup time 2250EV is again fastest. Since it is using epoll on my system, the setup time
1728is relatively high, though. 2251is relatively high, though.
1729 2252
1730Perl surprisingly comes second. It is much faster than the C-based event 2253Perl surprisingly comes second. It is much faster than the C-based event
1731loops Event and Glib. 2254loops Event and Glib.
2255
2256IO::Async performs very well when using its epoll backend, and still quite
2257good compared to Glib when using its pure perl backend.
1732 2258
1733Event suffers from high setup time as well (look at its code and you will 2259Event suffers from high setup time as well (look at its code and you will
1734understand why). Callback invocation also has a high overhead compared to 2260understand why). Callback invocation also has a high overhead compared to
1735the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 2261the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1736uses select or poll in basically all documented configurations. 2262uses select or poll in basically all documented configurations.
1799=item * C-based event loops perform very well with small number of 2325=item * C-based event loops perform very well with small number of
1800watchers, as the management overhead dominates. 2326watchers, as the management overhead dominates.
1801 2327
1802=back 2328=back
1803 2329
2330=head2 THE IO::Lambda BENCHMARK
2331
2332Recently I was told about the benchmark in the IO::Lambda manpage, which
2333could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
2334simply compares IO::Lambda with POE, and IO::Lambda looks better (which
2335shouldn't come as a surprise to anybody). As such, the benchmark is
2336fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
2337very optimal. But how would AnyEvent compare when used without the extra
2338baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
2339
2340The benchmark itself creates an echo-server, and then, for 500 times,
2341connects to the echo server, sends a line, waits for the reply, and then
2342creates the next connection. This is a rather bad benchmark, as it doesn't
2343test the efficiency of the framework or much non-blocking I/O, but it is a
2344benchmark nevertheless.
2345
2346 name runtime
2347 Lambda/select 0.330 sec
2348 + optimized 0.122 sec
2349 Lambda/AnyEvent 0.327 sec
2350 + optimized 0.138 sec
2351 Raw sockets/select 0.077 sec
2352 POE/select, components 0.662 sec
2353 POE/select, raw sockets 0.226 sec
2354 POE/select, optimized 0.404 sec
2355
2356 AnyEvent/select/nb 0.085 sec
2357 AnyEvent/EV/nb 0.068 sec
2358 +state machine 0.134 sec
2359
2360The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
2361benchmarks actually make blocking connects and use 100% blocking I/O,
2362defeating the purpose of an event-based solution. All of the newly
2363written AnyEvent benchmarks use 100% non-blocking connects (using
2364AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
2365resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
2366generally require a lot more bookkeeping and event handling than blocking
2367connects (which involve a single syscall only).
2368
2369The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
2370offers similar expressive power as POE and IO::Lambda, using conventional
2371Perl syntax. This means that both the echo server and the client are 100%
2372non-blocking, further placing it at a disadvantage.
2373
2374As you can see, the AnyEvent + EV combination even beats the
2375hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2376backend easily beats IO::Lambda and POE.
2377
2378And even the 100% non-blocking version written using the high-level (and
2379slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
2380large margin, even though it does all of DNS, tcp-connect and socket I/O
2381in a non-blocking way.
2382
2383The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2384F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2385part of the IO::lambda distribution and were used without any changes.
2386
1804 2387
1805=head1 SIGNALS 2388=head1 SIGNALS
1806 2389
1807AnyEvent currently installs handlers for these signals: 2390AnyEvent currently installs handlers for these signals:
1808 2391
1811=item SIGCHLD 2394=item SIGCHLD
1812 2395
1813A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2396A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1814emulation for event loops that do not support them natively. Also, some 2397emulation for event loops that do not support them natively. Also, some
1815event loops install a similar handler. 2398event loops install a similar handler.
2399
2400Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2401AnyEvent will reset it to default, to avoid losing child exit statuses.
1816 2402
1817=item SIGPIPE 2403=item SIGPIPE
1818 2404
1819A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2405A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1820when AnyEvent gets loaded. 2406when AnyEvent gets loaded.
1832 2418
1833=back 2419=back
1834 2420
1835=cut 2421=cut
1836 2422
2423undef $SIG{CHLD}
2424 if $SIG{CHLD} eq 'IGNORE';
2425
1837$SIG{PIPE} = sub { } 2426$SIG{PIPE} = sub { }
1838 unless defined $SIG{PIPE}; 2427 unless defined $SIG{PIPE};
2428
2429=head1 RECOMMENDED/OPTIONAL MODULES
2430
2431One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2432it's built-in modules) are required to use it.
2433
2434That does not mean that AnyEvent won't take advantage of some additional
2435modules if they are installed.
2436
2437This section epxlains which additional modules will be used, and how they
2438affect AnyEvent's operetion.
2439
2440=over 4
2441
2442=item L<Async::Interrupt>
2443
2444This slightly arcane module is used to implement fast signal handling: To
2445my knowledge, there is no way to do completely race-free and quick
2446signal handling in pure perl. To ensure that signals still get
2447delivered, AnyEvent will start an interval timer to wake up perl (and
2448catch the signals) with some delay (default is 10 seconds, look for
2449C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2450
2451If this module is available, then it will be used to implement signal
2452catching, which means that signals will not be delayed, and the event loop
2453will not be interrupted regularly, which is more efficient (And good for
2454battery life on laptops).
2455
2456This affects not just the pure-perl event loop, but also other event loops
2457that have no signal handling on their own (e.g. Glib, Tk, Qt).
2458
2459Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2460and either employ their own workarounds (POE) or use AnyEvent's workaround
2461(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2462does nothing for those backends.
2463
2464=item L<EV>
2465
2466This module isn't really "optional", as it is simply one of the backend
2467event loops that AnyEvent can use. However, it is simply the best event
2468loop available in terms of features, speed and stability: It supports
2469the AnyEvent API optimally, implements all the watcher types in XS, does
2470automatic timer adjustments even when no monotonic clock is available,
2471can take avdantage of advanced kernel interfaces such as C<epoll> and
2472C<kqueue>, and is the fastest backend I<by far>. You can even embed
2473L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2474
2475=item L<Guard>
2476
2477The guard module, when used, will be used to implement
2478C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2479lot less memory), but otherwise doesn't affect guard operation much. It is
2480purely used for performance.
2481
2482=item L<JSON> and L<JSON::XS>
2483
2484This module is required when you want to read or write JSON data via
2485L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2486advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2487
2488In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2489installed.
2490
2491=item L<Net::SSLeay>
2492
2493Implementing TLS/SSL in Perl is certainly interesting, but not very
2494worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2495the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2496
2497=item L<Time::HiRes>
2498
2499This module is part of perl since release 5.008. It will be used when the
2500chosen event library does not come with a timing source on it's own. The
2501pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2502try to use a monotonic clock for timing stability.
2503
2504=back
1839 2505
1840 2506
1841=head1 FORK 2507=head1 FORK
1842 2508
1843Most event libraries are not fork-safe. The ones who are usually are 2509Most event libraries are not fork-safe. The ones who are usually are
1844because they rely on inefficient but fork-safe C<select> or C<poll> 2510because they rely on inefficient but fork-safe C<select> or C<poll>
1845calls. Only L<EV> is fully fork-aware. 2511calls. Only L<EV> is fully fork-aware.
1846 2512
1847If you have to fork, you must either do so I<before> creating your first 2513If you have to fork, you must either do so I<before> creating your first
1848watcher OR you must not use AnyEvent at all in the child. 2514watcher OR you must not use AnyEvent at all in the child OR you must do
2515something completely out of the scope of AnyEvent.
1849 2516
1850 2517
1851=head1 SECURITY CONSIDERATIONS 2518=head1 SECURITY CONSIDERATIONS
1852 2519
1853AnyEvent can be forced to load any event model via 2520AnyEvent can be forced to load any event model via
1865 use AnyEvent; 2532 use AnyEvent;
1866 2533
1867Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2534Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1868be used to probe what backend is used and gain other information (which is 2535be used to probe what backend is used and gain other information (which is
1869probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2536probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1870$ENV{PERL_ANYEGENT_STRICT}. 2537$ENV{PERL_ANYEVENT_STRICT}.
2538
2539Note that AnyEvent will remove I<all> environment variables starting with
2540C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2541enabled.
1871 2542
1872 2543
1873=head1 BUGS 2544=head1 BUGS
1874 2545
1875Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2546Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1887L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2558L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1888 2559
1889Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2560Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1890L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2561L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1891L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2562L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1892L<AnyEvent::Impl::POE>. 2563L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1893 2564
1894Non-blocking file handles, sockets, TCP clients and 2565Non-blocking file handles, sockets, TCP clients and
1895servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2566servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1896 2567
1897Asynchronous DNS: L<AnyEvent::DNS>. 2568Asynchronous DNS: L<AnyEvent::DNS>.
1898 2569
1899Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2570Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2571L<Coro::Event>,
1900 2572
1901Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2573Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2574L<AnyEvent::HTTP>.
1902 2575
1903 2576
1904=head1 AUTHOR 2577=head1 AUTHOR
1905 2578
1906 Marc Lehmann <schmorp@schmorp.de> 2579 Marc Lehmann <schmorp@schmorp.de>

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