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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
368A typical example would be a script in a web server (e.g. C<mod_perl>) -
369when mod_perl executes the script, then the event loop will have the wrong
370idea about the "current time" (being potentially far in the past, when the
371script ran the last time). In that case you should arrange a call to C<<
372AnyEvent->now_update >> each time the web server process wakes up again
373(e.g. at the start of your script, or in a handler).
374
375Note that updating the time I<might> cause some events to be handled.
376
325=back 377=back
326 378
327=head2 SIGNAL WATCHERS 379=head2 SIGNAL WATCHERS
380
381 $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
328 382
329You can watch for signals using a signal watcher, C<signal> is the signal 383You 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 384I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
331callback to be invoked whenever a signal occurs. 385callback to be invoked whenever a signal occurs.
332 386
338invocation, and callback invocation will be synchronous. Synchronous means 392invocation, and callback invocation will be synchronous. Synchronous means
339that it might take a while until the signal gets handled by the process, 393that it might take a while until the signal gets handled by the process,
340but it is guaranteed not to interrupt any other callbacks. 394but it is guaranteed not to interrupt any other callbacks.
341 395
342The main advantage of using these watchers is that you can share a signal 396The main advantage of using these watchers is that you can share a signal
343between multiple watchers. 397between multiple watchers, and AnyEvent will ensure that signals will not
398interrupt your program at bad times.
344 399
345This watcher might use C<%SIG>, so programs overwriting those signals 400This watcher might use C<%SIG> (depending on the event loop used),
346directly will likely not work correctly. 401so programs overwriting those signals directly will likely not work
402correctly.
347 403
348Example: exit on SIGINT 404Example: exit on SIGINT
349 405
350 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 406 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
351 407
408=head3 Signal Races, Delays and Workarounds
409
410Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
411callbacks to signals in a generic way, which is a pity, as you cannot
412do race-free signal handling in perl, requiring C libraries for
413this. AnyEvent will try to do it's best, which means in some cases,
414signals will be delayed. The maximum time a signal might be delayed is
415specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
416variable can be changed only before the first signal watcher is created,
417and should be left alone otherwise. This variable determines how often
418AnyEvent polls for signals (in case a wake-up was missed). Higher values
419will cause fewer spurious wake-ups, which is better for power and CPU
420saving.
421
422All these problems can be avoided by installing the optional
423L<Async::Interrupt> module, which works with most event loops. It will not
424work with inherently broken event loops such as L<Event> or L<Event::Lib>
425(and not with L<POE> currently, as POE does it's own workaround with
426one-second latency). For those, you just have to suffer the delays.
427
352=head2 CHILD PROCESS WATCHERS 428=head2 CHILD PROCESS WATCHERS
353 429
430 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
431
354You can also watch on a child process exit and catch its exit status. 432You can also watch on a child process exit and catch its exit status.
355 433
356The child process is specified by the C<pid> argument (if set to C<0>, it 434The child process is specified by the C<pid> argument (one some backends,
357watches for any child process exit). The watcher will triggered only when 435using 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 436croak). The watcher will be triggered only when the child process has
359any trace events (stopped/continued). 437finished and an exit status is available, not on any trace events
438(stopped/continued).
360 439
361The callback will be called with the pid and exit status (as returned by 440The 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 441waitpid), so unlike other watcher types, you I<can> rely on child watcher
363callback arguments. 442callback arguments.
364 443
369 448
370There is a slight catch to child watchers, however: you usually start them 449There 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 450I<after> the child process was created, and this means the process could
372have exited already (and no SIGCHLD will be sent anymore). 451have exited already (and no SIGCHLD will be sent anymore).
373 452
374Not all event models handle this correctly (POE doesn't), but even for 453Not all event models handle this correctly (neither POE nor IO::Async do,
454see their AnyEvent::Impl manpages for details), but even for event models
375event models that I<do> handle this correctly, they usually need to be 455that 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). 456the process exits (i.e. before you fork in the first place). AnyEvent's
457pure perl event loop handles all cases correctly regardless of when you
458start the watcher.
377 459
378This means you cannot create a child watcher as the very first thing in an 460This means you cannot create a child watcher as the very first
379AnyEvent program, you I<have> to create at least one watcher before you 461thing in an AnyEvent program, you I<have> to create at least one
380C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 462watcher before you C<fork> the child (alternatively, you can call
463C<AnyEvent::detect>).
464
465As most event loops do not support waiting for child events, they will be
466emulated by AnyEvent in most cases, in which the latency and race problems
467mentioned in the description of signal watchers apply.
381 468
382Example: fork a process and wait for it 469Example: fork a process and wait for it
383 470
384 my $done = AnyEvent->condvar; 471 my $done = AnyEvent->condvar;
385 472
395 ); 482 );
396 483
397 # do something else, then wait for process exit 484 # do something else, then wait for process exit
398 $done->recv; 485 $done->recv;
399 486
487=head2 IDLE WATCHERS
488
489 $w = AnyEvent->idle (cb => <callback>);
490
491Sometimes there is a need to do something, but it is not so important
492to do it instantly, but only when there is nothing better to do. This
493"nothing better to do" is usually defined to be "no other events need
494attention by the event loop".
495
496Idle watchers ideally get invoked when the event loop has nothing
497better to do, just before it would block the process to wait for new
498events. Instead of blocking, the idle watcher is invoked.
499
500Most event loops unfortunately do not really support idle watchers (only
501EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
502will simply call the callback "from time to time".
503
504Example: read lines from STDIN, but only process them when the
505program is otherwise idle:
506
507 my @lines; # read data
508 my $idle_w;
509 my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
510 push @lines, scalar <STDIN>;
511
512 # start an idle watcher, if not already done
513 $idle_w ||= AnyEvent->idle (cb => sub {
514 # handle only one line, when there are lines left
515 if (my $line = shift @lines) {
516 print "handled when idle: $line";
517 } else {
518 # otherwise disable the idle watcher again
519 undef $idle_w;
520 }
521 });
522 });
523
400=head2 CONDITION VARIABLES 524=head2 CONDITION VARIABLES
525
526 $cv = AnyEvent->condvar;
527
528 $cv->send (<list>);
529 my @res = $cv->recv;
401 530
402If you are familiar with some event loops you will know that all of them 531If 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 532require you to run some blocking "loop", "run" or similar function that
404will actively watch for new events and call your callbacks. 533will actively watch for new events and call your callbacks.
405 534
406AnyEvent is different, it expects somebody else to run the event loop and 535AnyEvent is slightly different: it expects somebody else to run the event
407will only block when necessary (usually when told by the user). 536loop and will only block when necessary (usually when told by the user).
408 537
409The instrument to do that is called a "condition variable", so called 538The instrument to do that is called a "condition variable", so called
410because they represent a condition that must become true. 539because they represent a condition that must become true.
411 540
541Now is probably a good time to look at the examples further below.
542
412Condition variables can be created by calling the C<< AnyEvent->condvar 543Condition variables can be created by calling the C<< AnyEvent->condvar
413>> method, usually without arguments. The only argument pair allowed is 544>> method, usually without arguments. The only argument pair allowed is
414
415C<cb>, which specifies a callback to be called when the condition variable 545C<cb>, which specifies a callback to be called when the condition variable
416becomes true, with the condition variable as the first argument (but not 546becomes true, with the condition variable as the first argument (but not
417the results). 547the results).
418 548
419After creation, the condition variable is "false" until it becomes "true" 549After creation, the condition variable is "false" until it becomes "true"
424Condition variables are similar to callbacks, except that you can 554Condition variables are similar to callbacks, except that you can
425optionally wait for them. They can also be called merge points - points 555optionally wait for them. They can also be called merge points - points
426in time where multiple outstanding events have been processed. And yet 556in time where multiple outstanding events have been processed. And yet
427another way to call them is transactions - each condition variable can be 557another way to call them is transactions - each condition variable can be
428used to represent a transaction, which finishes at some point and delivers 558used to represent a transaction, which finishes at some point and delivers
429a result. 559a result. And yet some people know them as "futures" - a promise to
560compute/deliver something that you can wait for.
430 561
431Condition variables are very useful to signal that something has finished, 562Condition variables are very useful to signal that something has finished,
432for example, if you write a module that does asynchronous http requests, 563for example, if you write a module that does asynchronous http requests,
433then a condition variable would be the ideal candidate to signal the 564then a condition variable would be the ideal candidate to signal the
434availability of results. The user can either act when the callback is 565availability of results. The user can either act when the callback is
468 after => 1, 599 after => 1,
469 cb => sub { $result_ready->send }, 600 cb => sub { $result_ready->send },
470 ); 601 );
471 602
472 # this "blocks" (while handling events) till the callback 603 # this "blocks" (while handling events) till the callback
473 # calls send 604 # calls ->send
474 $result_ready->recv; 605 $result_ready->recv;
475 606
476Example: wait for a timer, but take advantage of the fact that 607Example: wait for a timer, but take advantage of the fact that condition
477condition variables are also code references. 608variables are also callable directly.
478 609
479 my $done = AnyEvent->condvar; 610 my $done = AnyEvent->condvar;
480 my $delay = AnyEvent->timer (after => 5, cb => $done); 611 my $delay = AnyEvent->timer (after => 5, cb => $done);
481 $done->recv; 612 $done->recv;
482 613
488 619
489 ... 620 ...
490 621
491 my @info = $couchdb->info->recv; 622 my @info = $couchdb->info->recv;
492 623
493And this is how you would just ste a callback to be called whenever the 624And this is how you would just set a callback to be called whenever the
494results are available: 625results are available:
495 626
496 $couchdb->info->cb (sub { 627 $couchdb->info->cb (sub {
497 my @info = $_[0]->recv; 628 my @info = $_[0]->recv;
498 }); 629 });
516immediately from within send. 647immediately from within send.
517 648
518Any arguments passed to the C<send> call will be returned by all 649Any arguments passed to the C<send> call will be returned by all
519future C<< ->recv >> calls. 650future C<< ->recv >> calls.
520 651
521Condition variables are overloaded so one can call them directly 652Condition variables are overloaded so one can call them directly (as if
522(as a code reference). Calling them directly is the same as calling 653they 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 654C<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).
529 655
530=item $cv->croak ($error) 656=item $cv->croak ($error)
531 657
532Similar to send, but causes all call's to C<< ->recv >> to invoke 658Similar to send, but causes all call's to C<< ->recv >> to invoke
533C<Carp::croak> with the given error message/object/scalar. 659C<Carp::croak> with the given error message/object/scalar.
534 660
535This can be used to signal any errors to the condition variable 661This can be used to signal any errors to the condition variable
536user/consumer. 662user/consumer. Doing it this way instead of calling C<croak> directly
663delays the error detetcion, but has the overwhelmign advantage that it
664diagnoses the error at the place where the result is expected, and not
665deep in some event clalback without connection to the actual code causing
666the problem.
537 667
538=item $cv->begin ([group callback]) 668=item $cv->begin ([group callback])
539 669
540=item $cv->end 670=item $cv->end
541
542These two methods are EXPERIMENTAL and MIGHT CHANGE.
543 671
544These two methods can be used to combine many transactions/events into 672These two methods can be used to combine many transactions/events into
545one. For example, a function that pings many hosts in parallel might want 673one. For example, a function that pings many hosts in parallel might want
546to use a condition variable for the whole process. 674to use a condition variable for the whole process.
547 675
548Every call to C<< ->begin >> will increment a counter, and every call to 676Every call to C<< ->begin >> will increment a counter, and every call to
549C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 677C<< ->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 678>>, the (last) callback passed to C<begin> will be executed, passing the
551is I<supposed> to call C<< ->send >>, but that is not required. If no 679condvar as first argument. That callback is I<supposed> to call C<< ->send
552callback was set, C<send> will be called without any arguments. 680>>, but that is not required. If no group callback was set, C<send> will
681be called without any arguments.
553 682
554Let's clarify this with the ping example: 683You can think of C<< $cv->send >> giving you an OR condition (one call
684sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
685condition (all C<begin> calls must be C<end>'ed before the condvar sends).
686
687Let's start with a simple example: you have two I/O watchers (for example,
688STDOUT and STDERR for a program), and you want to wait for both streams to
689close before activating a condvar:
555 690
556 my $cv = AnyEvent->condvar; 691 my $cv = AnyEvent->condvar;
557 692
693 $cv->begin; # first watcher
694 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
695 defined sysread $fh1, my $buf, 4096
696 or $cv->end;
697 });
698
699 $cv->begin; # second watcher
700 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
701 defined sysread $fh2, my $buf, 4096
702 or $cv->end;
703 });
704
705 $cv->recv;
706
707This works because for every event source (EOF on file handle), there is
708one call to C<begin>, so the condvar waits for all calls to C<end> before
709sending.
710
711The ping example mentioned above is slightly more complicated, as the
712there are results to be passwd back, and the number of tasks that are
713begung can potentially be zero:
714
715 my $cv = AnyEvent->condvar;
716
558 my %result; 717 my %result;
559 $cv->begin (sub { $cv->send (\%result) }); 718 $cv->begin (sub { shift->send (\%result) });
560 719
561 for my $host (@list_of_hosts) { 720 for my $host (@list_of_hosts) {
562 $cv->begin; 721 $cv->begin;
563 ping_host_then_call_callback $host, sub { 722 ping_host_then_call_callback $host, sub {
564 $result{$host} = ...; 723 $result{$host} = ...;
579loop, which serves two important purposes: first, it sets the callback 738loop, which serves two important purposes: first, it sets the callback
580to be called once the counter reaches C<0>, and second, it ensures that 739to 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 740C<send> is called even when C<no> hosts are being pinged (the loop
582doesn't execute once). 741doesn't execute once).
583 742
584This is the general pattern when you "fan out" into multiple subrequests: 743This 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> 744potentially 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 745the 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>. 746subrequest you start, call C<begin> and for each subrequest you finish,
747call C<end>.
588 748
589=back 749=back
590 750
591=head3 METHODS FOR CONSUMERS 751=head3 METHODS FOR CONSUMERS
592 752
608function will call C<croak>. 768function will call C<croak>.
609 769
610In list context, all parameters passed to C<send> will be returned, 770In list context, all parameters passed to C<send> will be returned,
611in scalar context only the first one will be returned. 771in scalar context only the first one will be returned.
612 772
773Note that doing a blocking wait in a callback is not supported by any
774event loop, that is, recursive invocation of a blocking C<< ->recv
775>> is not allowed, and the C<recv> call will C<croak> if such a
776condition is detected. This condition can be slightly loosened by using
777L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
778any thread that doesn't run the event loop itself.
779
613Not all event models support a blocking wait - some die in that case 780Not 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 781(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 782using 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 783caller decide whether the call will block or not (for example, by coupling
617condition variables with some kind of request results and supporting 784condition variables with some kind of request results and supporting
618callbacks so the caller knows that getting the result will not block, 785callbacks so the caller knows that getting the result will not block,
619while still supporting blocking waits if the caller so desires). 786while still supporting blocking waits if the caller so desires).
620 787
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 788You can ensure that C<< -recv >> never blocks by setting a callback and
633only calling C<< ->recv >> from within that callback (or at a later 789only calling C<< ->recv >> from within that callback (or at a later
634time). This will work even when the event loop does not support blocking 790time). This will work even when the event loop does not support blocking
635waits otherwise. 791waits otherwise.
636 792
642=item $cb = $cv->cb ($cb->($cv)) 798=item $cb = $cv->cb ($cb->($cv))
643 799
644This is a mutator function that returns the callback set and optionally 800This is a mutator function that returns the callback set and optionally
645replaces it before doing so. 801replaces it before doing so.
646 802
647The callback will be called when the condition becomes "true", i.e. when 803The 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 804"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 805the only argument being the condition variable itself. Calling C<recv>
650is guaranteed not to block. 806inside the callback or at any later time is guaranteed not to block.
651 807
652=back 808=back
653 809
810=head1 SUPPORTED EVENT LOOPS/BACKENDS
811
812The available backend classes are (every class has its own manpage):
813
814=over 4
815
816=item Backends that are autoprobed when no other event loop can be found.
817
818EV is the preferred backend when no other event loop seems to be in
819use. If EV is not installed, then AnyEvent will fall back to its own
820pure-perl implementation, which is available everywhere as it comes with
821AnyEvent itself.
822
823 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
824 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
825
826=item Backends that are transparently being picked up when they are used.
827
828These will be used when they are currently loaded when the first watcher
829is created, in which case it is assumed that the application is using
830them. This means that AnyEvent will automatically pick the right backend
831when the main program loads an event module before anything starts to
832create watchers. Nothing special needs to be done by the main program.
833
834 AnyEvent::Impl::Event based on Event, very stable, few glitches.
835 AnyEvent::Impl::Glib based on Glib, slow but very stable.
836 AnyEvent::Impl::Tk based on Tk, very broken.
837 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
838 AnyEvent::Impl::POE based on POE, very slow, some limitations.
839 AnyEvent::Impl::Irssi used when running within irssi.
840
841=item Backends with special needs.
842
843Qt requires the Qt::Application to be instantiated first, but will
844otherwise be picked up automatically. As long as the main program
845instantiates the application before any AnyEvent watchers are created,
846everything should just work.
847
848 AnyEvent::Impl::Qt based on Qt.
849
850Support for IO::Async can only be partial, as it is too broken and
851architecturally limited to even support the AnyEvent API. It also
852is the only event loop that needs the loop to be set explicitly, so
853it can only be used by a main program knowing about AnyEvent. See
854L<AnyEvent::Impl::Async> for the gory details.
855
856 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
857
858=item Event loops that are indirectly supported via other backends.
859
860Some event loops can be supported via other modules:
861
862There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
863
864B<WxWidgets> has no support for watching file handles. However, you can
865use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
866polls 20 times per second, which was considered to be too horrible to even
867consider for AnyEvent.
868
869B<Prima> is not supported as nobody seems to be using it, but it has a POE
870backend, so it can be supported through POE.
871
872AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
873load L<POE> when detecting them, in the hope that POE will pick them up,
874in which case everything will be automatic.
875
876=back
877
654=head1 GLOBAL VARIABLES AND FUNCTIONS 878=head1 GLOBAL VARIABLES AND FUNCTIONS
655 879
880These are not normally required to use AnyEvent, but can be useful to
881write AnyEvent extension modules.
882
656=over 4 883=over 4
657 884
658=item $AnyEvent::MODEL 885=item $AnyEvent::MODEL
659 886
660Contains C<undef> until the first watcher is being created. Then it 887Contains C<undef> until the first watcher is being created, before the
888backend has been autodetected.
889
661contains the event model that is being used, which is the name of the 890Afterwards it contains the event model that is being used, which is the
662Perl class implementing the model. This class is usually one of the 891name of the Perl class implementing the model. This class is usually one
663C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 892of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
664AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 893case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
665 894will be C<urxvt::anyevent>).
666The known classes so far are:
667
668 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
669 AnyEvent::Impl::Event based on Event, second best choice.
670 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
671 AnyEvent::Impl::Glib based on Glib, third-best choice.
672 AnyEvent::Impl::Tk based on Tk, very bad choice.
673 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
674 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
675 AnyEvent::Impl::POE based on POE, not generic enough for full support.
676
677There is no support for WxWidgets, as WxWidgets has no support for
678watching file handles. However, you can use WxWidgets through the
679POE Adaptor, as POE has a Wx backend that simply polls 20 times per
680second, which was considered to be too horrible to even consider for
681AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
682it's adaptor.
683
684AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
685autodetecting them.
686 895
687=item AnyEvent::detect 896=item AnyEvent::detect
688 897
689Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 898Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
690if necessary. You should only call this function right before you would 899if necessary. You should only call this function right before you would
691have created an AnyEvent watcher anyway, that is, as late as possible at 900have created an AnyEvent watcher anyway, that is, as late as possible at
692runtime. 901runtime, and not e.g. while initialising of your module.
902
903If you need to do some initialisation before AnyEvent watchers are
904created, use C<post_detect>.
693 905
694=item $guard = AnyEvent::post_detect { BLOCK } 906=item $guard = AnyEvent::post_detect { BLOCK }
695 907
696Arranges for the code block to be executed as soon as the event model is 908Arranges for the code block to be executed as soon as the event model is
697autodetected (or immediately if this has already happened). 909autodetected (or immediately if this has already happened).
698 910
911The block will be executed I<after> the actual backend has been detected
912(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
913created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
914other initialisations - see the sources of L<AnyEvent::Strict> or
915L<AnyEvent::AIO> to see how this is used.
916
917The most common usage is to create some global watchers, without forcing
918event module detection too early, for example, L<AnyEvent::AIO> creates
919and installs the global L<IO::AIO> watcher in a C<post_detect> block to
920avoid autodetecting the event module at load time.
921
699If called in scalar or list context, then it creates and returns an object 922If called in scalar or list context, then it creates and returns an object
700that automatically removes the callback again when it is destroyed. See 923that automatically removes the callback again when it is destroyed (or
924C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
701L<Coro::BDB> for a case where this is useful. 925a case where this is useful.
926
927Example: Create a watcher for the IO::AIO module and store it in
928C<$WATCHER>. Only do so after the event loop is initialised, though.
929
930 our WATCHER;
931
932 my $guard = AnyEvent::post_detect {
933 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
934 };
935
936 # the ||= is important in case post_detect immediately runs the block,
937 # as to not clobber the newly-created watcher. assigning both watcher and
938 # post_detect guard to the same variable has the advantage of users being
939 # able to just C<undef $WATCHER> if the watcher causes them grief.
940
941 $WATCHER ||= $guard;
702 942
703=item @AnyEvent::post_detect 943=item @AnyEvent::post_detect
704 944
705If there are any code references in this array (you can C<push> to it 945If there are any code references in this array (you can C<push> to it
706before or after loading AnyEvent), then they will called directly after 946before or after loading AnyEvent), then they will called directly after
707the event loop has been chosen. 947the event loop has been chosen.
708 948
709You should check C<$AnyEvent::MODEL> before adding to this array, though: 949You 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, 950if it is defined then the event loop has already been detected, and the
711and the array will be ignored. 951array will be ignored.
712 952
713Best use C<AnyEvent::post_detect { BLOCK }> instead. 953Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
954it,as it takes care of these details.
955
956This variable is mainly useful for modules that can do something useful
957when AnyEvent is used and thus want to know when it is initialised, but do
958not need to even load it by default. This array provides the means to hook
959into AnyEvent passively, without loading it.
714 960
715=back 961=back
716 962
717=head1 WHAT TO DO IN A MODULE 963=head1 WHAT TO DO IN A MODULE
718 964
773 1019
774 1020
775=head1 OTHER MODULES 1021=head1 OTHER MODULES
776 1022
777The following is a non-exhaustive list of additional modules that use 1023The following is a non-exhaustive list of additional modules that use
778AnyEvent and can therefore be mixed easily with other AnyEvent modules 1024AnyEvent 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 1025modules and other event loops in the same program. Some of the modules
780available via CPAN. 1026come with AnyEvent, most are available via CPAN.
781 1027
782=over 4 1028=over 4
783 1029
784=item L<AnyEvent::Util> 1030=item L<AnyEvent::Util>
785 1031
794 1040
795=item L<AnyEvent::Handle> 1041=item L<AnyEvent::Handle>
796 1042
797Provide read and write buffers, manages watchers for reads and writes, 1043Provide read and write buffers, manages watchers for reads and writes,
798supports raw and formatted I/O, I/O queued and fully transparent and 1044supports raw and formatted I/O, I/O queued and fully transparent and
799non-blocking SSL/TLS. 1045non-blocking SSL/TLS (via L<AnyEvent::TLS>.
800 1046
801=item L<AnyEvent::DNS> 1047=item L<AnyEvent::DNS>
802 1048
803Provides rich asynchronous DNS resolver capabilities. 1049Provides rich asynchronous DNS resolver capabilities.
804 1050
832 1078
833=item L<AnyEvent::GPSD> 1079=item L<AnyEvent::GPSD>
834 1080
835A non-blocking interface to gpsd, a daemon delivering GPS information. 1081A non-blocking interface to gpsd, a daemon delivering GPS information.
836 1082
1083=item L<AnyEvent::IRC>
1084
1085AnyEvent based IRC client module family (replacing the older Net::IRC3).
1086
1087=item L<AnyEvent::XMPP>
1088
1089AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1090Net::XMPP2>.
1091
837=item L<AnyEvent::IGS> 1092=item L<AnyEvent::IGS>
838 1093
839A non-blocking interface to the Internet Go Server protocol (used by 1094A non-blocking interface to the Internet Go Server protocol (used by
840L<App::IGS>). 1095L<App::IGS>).
841 1096
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> 1097=item L<Net::FCP>
851 1098
852AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1099AnyEvent-based implementation of the Freenet Client Protocol, birthplace
853of AnyEvent. 1100of AnyEvent.
854 1101
858 1105
859=item L<Coro> 1106=item L<Coro>
860 1107
861Has special support for AnyEvent via L<Coro::AnyEvent>. 1108Has special support for AnyEvent via L<Coro::AnyEvent>.
862 1109
863=item L<IO::Lambda>
864
865The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
866
867=back 1110=back
868 1111
869=cut 1112=cut
870 1113
871package AnyEvent; 1114package AnyEvent;
872 1115
873no warnings; 1116# basically a tuned-down version of common::sense
1117sub common_sense {
1118 # from common:.sense 1.0
1119 ${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";
874use strict qw(vars subs); 1120 # use strict vars subs
1121 $^H |= 0x00000600;
1122}
875 1123
1124BEGIN { AnyEvent::common_sense }
1125
876use Carp; 1126use Carp ();
877 1127
878our $VERSION = 4.35; 1128our $VERSION = '5.21';
879our $MODEL; 1129our $MODEL;
880 1130
881our $AUTOLOAD; 1131our $AUTOLOAD;
882our @ISA; 1132our @ISA;
883 1133
884our @REGISTRY; 1134our @REGISTRY;
885 1135
886our $WIN32; 1136our $VERBOSE;
887 1137
888BEGIN { 1138BEGIN {
889 my $win32 = ! ! ($^O =~ /mswin32/i); 1139 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
890 eval "sub WIN32(){ $win32 }"; 1140 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
891}
892 1141
1142 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1143 if ${^TAINT};
1144
893our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1145 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1146
1147}
1148
1149our $MAX_SIGNAL_LATENCY = 10;
894 1150
895our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1151our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
896 1152
897{ 1153{
898 my $idx; 1154 my $idx;
900 for reverse split /\s*,\s*/, 1156 for reverse split /\s*,\s*/,
901 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1157 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
902} 1158}
903 1159
904my @models = ( 1160my @models = (
905 [EV:: => AnyEvent::Impl::EV::], 1161 [EV:: => AnyEvent::Impl::EV:: , 1],
906 [Event:: => AnyEvent::Impl::Event::],
907 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1162 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
908 # everything below here will not be autoprobed 1163 # everything below here will not (normally) be autoprobed
909 # as the pureperl backend should work everywhere 1164 # as the pureperl backend should work everywhere
910 # and is usually faster 1165 # and is usually faster
1166 [Event:: => AnyEvent::Impl::Event::, 1],
1167 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1168 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1169 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
911 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1170 [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 1171 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
915 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1172 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
916 [Wx:: => AnyEvent::Impl::POE::], 1173 [Wx:: => AnyEvent::Impl::POE::],
917 [Prima:: => AnyEvent::Impl::POE::], 1174 [Prima:: => AnyEvent::Impl::POE::],
1175 # IO::Async is just too broken - we would need workarounds for its
1176 # byzantine signal and broken child handling, among others.
1177 # IO::Async is rather hard to detect, as it doesn't have any
1178 # obvious default class.
1179 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1180 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1181 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1182 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
918); 1183);
919 1184
920our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 1185our %method = map +($_ => 1),
1186 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
921 1187
922our @post_detect; 1188our @post_detect;
923 1189
924sub post_detect(&) { 1190sub post_detect(&) {
925 my ($cb) = @_; 1191 my ($cb) = @_;
926 1192
927 if ($MODEL) { 1193 if ($MODEL) {
928 $cb->(); 1194 $cb->();
929 1195
930 1 1196 undef
931 } else { 1197 } else {
932 push @post_detect, $cb; 1198 push @post_detect, $cb;
933 1199
934 defined wantarray 1200 defined wantarray
935 ? bless \$cb, "AnyEvent::Util::PostDetect" 1201 ? bless \$cb, "AnyEvent::Util::postdetect"
936 : () 1202 : ()
937 } 1203 }
938} 1204}
939 1205
940sub AnyEvent::Util::PostDetect::DESTROY { 1206sub AnyEvent::Util::postdetect::DESTROY {
941 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1207 @post_detect = grep $_ != ${$_[0]}, @post_detect;
942} 1208}
943 1209
944sub detect() { 1210sub detect() {
945 unless ($MODEL) { 1211 unless ($MODEL) {
946 no strict 'refs';
947 local $SIG{__DIE__}; 1212 local $SIG{__DIE__};
948 1213
949 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1214 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
950 my $model = "AnyEvent::Impl::$1"; 1215 my $model = "AnyEvent::Impl::$1";
951 if (eval "require $model") { 1216 if (eval "require $model") {
952 $MODEL = $model; 1217 $MODEL = $model;
953 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1218 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
954 } else { 1219 } else {
955 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1220 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
956 } 1221 }
957 } 1222 }
958 1223
959 # check for already loaded models 1224 # check for already loaded models
960 unless ($MODEL) { 1225 unless ($MODEL) {
961 for (@REGISTRY, @models) { 1226 for (@REGISTRY, @models) {
962 my ($package, $model) = @$_; 1227 my ($package, $model) = @$_;
963 if (${"$package\::VERSION"} > 0) { 1228 if (${"$package\::VERSION"} > 0) {
964 if (eval "require $model") { 1229 if (eval "require $model") {
965 $MODEL = $model; 1230 $MODEL = $model;
966 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1231 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
967 last; 1232 last;
968 } 1233 }
969 } 1234 }
970 } 1235 }
971 1236
972 unless ($MODEL) { 1237 unless ($MODEL) {
973 # try to load a model 1238 # try to autoload a model
974
975 for (@REGISTRY, @models) { 1239 for (@REGISTRY, @models) {
976 my ($package, $model) = @$_; 1240 my ($package, $model, $autoload) = @$_;
1241 if (
1242 $autoload
977 if (eval "require $package" 1243 and eval "require $package"
978 and ${"$package\::VERSION"} > 0 1244 and ${"$package\::VERSION"} > 0
979 and eval "require $model") { 1245 and eval "require $model"
1246 ) {
980 $MODEL = $model; 1247 $MODEL = $model;
981 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1248 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
982 last; 1249 last;
983 } 1250 }
984 } 1251 }
985 1252
986 $MODEL 1253 $MODEL
987 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1254 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
988 } 1255 }
989 } 1256 }
990 1257
991 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1258 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
992 1259
1002 1269
1003sub AUTOLOAD { 1270sub AUTOLOAD {
1004 (my $func = $AUTOLOAD) =~ s/.*://; 1271 (my $func = $AUTOLOAD) =~ s/.*://;
1005 1272
1006 $method{$func} 1273 $method{$func}
1007 or croak "$func: not a valid method for AnyEvent objects"; 1274 or Carp::croak "$func: not a valid method for AnyEvent objects";
1008 1275
1009 detect unless $MODEL; 1276 detect unless $MODEL;
1010 1277
1011 my $class = shift; 1278 my $class = shift;
1012 $class->$func (@_); 1279 $class->$func (@_);
1013} 1280}
1014 1281
1015# utility function to dup a filehandle. this is used by many backends 1282# utility function to dup a filehandle. this is used by many backends
1016# to support binding more than one watcher per filehandle (they usually 1283# 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). 1284# allow only one watcher per fd, so we dup it to get a different one).
1018sub _dupfh($$$$) { 1285sub _dupfh($$;$$) {
1019 my ($poll, $fh, $r, $w) = @_; 1286 my ($poll, $fh, $r, $w) = @_;
1020 1287
1021 # cygwin requires the fh mode to be matching, unix doesn't 1288 # cygwin requires the fh mode to be matching, unix doesn't
1022 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1289 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1023 : $poll eq "w" ? ($w, ">")
1024 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1025 1290
1026 open my $fh2, "$mode&" . fileno $fh 1291 open my $fh2, $mode, $fh
1027 or die "cannot dup() filehandle: $!"; 1292 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1028 1293
1029 # we assume CLOEXEC is already set by perl in all important cases 1294 # we assume CLOEXEC is already set by perl in all important cases
1030 1295
1031 ($fh2, $rw) 1296 ($fh2, $rw)
1032} 1297}
1033 1298
1299=head1 SIMPLIFIED AE API
1300
1301Starting with version 5.0, AnyEvent officially supports a second, much
1302simpler, API that is designed to reduce the calling, typing and memory
1303overhead.
1304
1305See the L<AE> manpage for details.
1306
1307=cut
1308
1309package AE;
1310
1311our $VERSION = $AnyEvent::VERSION;
1312
1313sub io($$$) {
1314 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1315}
1316
1317sub timer($$$) {
1318 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1319}
1320
1321sub signal($$) {
1322 AnyEvent->signal (signal => $_[0], cb => $_[1])
1323}
1324
1325sub child($$) {
1326 AnyEvent->child (pid => $_[0], cb => $_[1])
1327}
1328
1329sub idle($) {
1330 AnyEvent->idle (cb => $_[0])
1331}
1332
1333sub cv(;&) {
1334 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1335}
1336
1337sub now() {
1338 AnyEvent->now
1339}
1340
1341sub now_update() {
1342 AnyEvent->now_update
1343}
1344
1345sub time() {
1346 AnyEvent->time
1347}
1348
1034package AnyEvent::Base; 1349package AnyEvent::Base;
1035 1350
1036# default implementation for now and time 1351# default implementations for many methods
1037 1352
1038BEGIN { 1353sub _time() {
1354 # probe for availability of Time::HiRes
1039 if (eval "use Time::HiRes (); time (); 1") { 1355 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1356 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1040 *_time = \&Time::HiRes::time; 1357 *_time = \&Time::HiRes::time;
1041 # if (eval "use POSIX (); (POSIX::times())... 1358 # if (eval "use POSIX (); (POSIX::times())...
1042 } else { 1359 } else {
1360 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1043 *_time = sub { time }; # epic fail 1361 *_time = sub { time }; # epic fail
1044 } 1362 }
1363
1364 &_time
1045} 1365}
1046 1366
1047sub time { _time } 1367sub time { _time }
1048sub now { _time } 1368sub now { _time }
1369sub now_update { }
1049 1370
1050# default implementation for ->condvar 1371# default implementation for ->condvar
1051 1372
1052sub condvar { 1373sub condvar {
1053 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1374 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1054} 1375}
1055 1376
1056# default implementation for ->signal 1377# default implementation for ->signal
1057 1378
1379our $HAVE_ASYNC_INTERRUPT;
1380
1381sub _have_async_interrupt() {
1382 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1383 && eval "use Async::Interrupt 1.02 (); 1")
1384 unless defined $HAVE_ASYNC_INTERRUPT;
1385
1386 $HAVE_ASYNC_INTERRUPT
1387}
1388
1058our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1389our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1390our (%SIG_ASY, %SIG_ASY_W);
1391our ($SIG_COUNT, $SIG_TW);
1059 1392
1060sub _signal_exec { 1393sub _signal_exec {
1394 $HAVE_ASYNC_INTERRUPT
1395 ? $SIGPIPE_R->drain
1061 sysread $SIGPIPE_R, my $dummy, 4; 1396 : sysread $SIGPIPE_R, (my $dummy), 9;
1062 1397
1063 while (%SIG_EV) { 1398 while (%SIG_EV) {
1064 for (keys %SIG_EV) { 1399 for (keys %SIG_EV) {
1065 delete $SIG_EV{$_}; 1400 delete $SIG_EV{$_};
1066 $_->() for values %{ $SIG_CB{$_} || {} }; 1401 $_->() for values %{ $SIG_CB{$_} || {} };
1067 } 1402 }
1068 } 1403 }
1069} 1404}
1070 1405
1406# install a dummy wakeup watcher to reduce signal catching latency
1407sub _sig_add() {
1408 unless ($SIG_COUNT++) {
1409 # try to align timer on a full-second boundary, if possible
1410 my $NOW = AE::now;
1411
1412 $SIG_TW = AE::timer
1413 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1414 $MAX_SIGNAL_LATENCY,
1415 sub { } # just for the PERL_ASYNC_CHECK
1416 ;
1417 }
1418}
1419
1420sub _sig_del {
1421 undef $SIG_TW
1422 unless --$SIG_COUNT;
1423}
1424
1425our $_sig_name_init; $_sig_name_init = sub {
1426 eval q{ # poor man's autoloading
1427 undef $_sig_name_init;
1428
1429 if (_have_async_interrupt) {
1430 *sig2num = \&Async::Interrupt::sig2num;
1431 *sig2name = \&Async::Interrupt::sig2name;
1432 } else {
1433 require Config;
1434
1435 my %signame2num;
1436 @signame2num{ split ' ', $Config::Config{sig_name} }
1437 = split ' ', $Config::Config{sig_num};
1438
1439 my @signum2name;
1440 @signum2name[values %signame2num] = keys %signame2num;
1441
1442 *sig2num = sub($) {
1443 $_[0] > 0 ? shift : $signame2num{+shift}
1444 };
1445 *sig2name = sub ($) {
1446 $_[0] > 0 ? $signum2name[+shift] : shift
1447 };
1448 }
1449 };
1450 die if $@;
1451};
1452
1453sub sig2num ($) { &$_sig_name_init; &sig2num }
1454sub sig2name($) { &$_sig_name_init; &sig2name }
1455
1071sub signal { 1456sub signal {
1072 my (undef, %arg) = @_; 1457 eval q{ # poor man's autoloading {}
1458 # probe for availability of Async::Interrupt
1459 if (_have_async_interrupt) {
1460 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1073 1461
1074 unless ($SIGPIPE_R) { 1462 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1075 require Fcntl; 1463 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1076 1464
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 { 1465 } else {
1466 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1467
1468 require Fcntl;
1469
1470 if (AnyEvent::WIN32) {
1471 require AnyEvent::Util;
1472
1473 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1474 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1475 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1476 } else {
1084 pipe $SIGPIPE_R, $SIGPIPE_W; 1477 pipe $SIGPIPE_R, $SIGPIPE_W;
1085 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1478 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 1479 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1480
1481 # not strictly required, as $^F is normally 2, but let's make sure...
1482 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1483 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1484 }
1485
1486 $SIGPIPE_R
1487 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1488
1489 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1087 } 1490 }
1088 1491
1089 $SIGPIPE_R 1492 *signal = sub {
1090 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1493 my (undef, %arg) = @_;
1091 1494
1092 # not strictly required, as $^F is normally 2, but let's make sure...
1093 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1095
1096 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1097 }
1098
1099 my $signal = uc $arg{signal} 1495 my $signal = uc $arg{signal}
1100 or Carp::croak "required option 'signal' is missing"; 1496 or Carp::croak "required option 'signal' is missing";
1101 1497
1498 if ($HAVE_ASYNC_INTERRUPT) {
1499 # async::interrupt
1500
1501 $signal = sig2num $signal;
1102 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1502 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1503
1504 $SIG_ASY{$signal} ||= new Async::Interrupt
1505 cb => sub { undef $SIG_EV{$signal} },
1506 signal => $signal,
1507 pipe => [$SIGPIPE_R->filenos],
1508 pipe_autodrain => 0,
1509 ;
1510
1511 } else {
1512 # pure perl
1513
1514 # AE::Util has been loaded in signal
1515 $signal = sig2name $signal;
1516 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1517
1103 $SIG{$signal} ||= sub { 1518 $SIG{$signal} ||= sub {
1104 local $!; 1519 local $!;
1105 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1520 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1106 undef $SIG_EV{$signal}; 1521 undef $SIG_EV{$signal};
1522 };
1523
1524 # can't do signal processing without introducing races in pure perl,
1525 # so limit the signal latency.
1526 _sig_add;
1527 }
1528
1529 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1530 };
1531
1532 *AnyEvent::Base::signal::DESTROY = sub {
1533 my ($signal, $cb) = @{$_[0]};
1534
1535 _sig_del;
1536
1537 delete $SIG_CB{$signal}{$cb};
1538
1539 $HAVE_ASYNC_INTERRUPT
1540 ? delete $SIG_ASY{$signal}
1541 : # delete doesn't work with older perls - they then
1542 # print weird messages, or just unconditionally exit
1543 # instead of getting the default action.
1544 undef $SIG{$signal}
1545 unless keys %{ $SIG_CB{$signal} };
1546 };
1107 }; 1547 };
1108 1548 die if $@;
1109 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1549 &signal
1110}
1111
1112sub AnyEvent::Base::Signal::DESTROY {
1113 my ($signal, $cb) = @{$_[0]};
1114
1115 delete $SIG_CB{$signal}{$cb};
1116
1117 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1118} 1550}
1119 1551
1120# default implementation for ->child 1552# default implementation for ->child
1121 1553
1122our %PID_CB; 1554our %PID_CB;
1123our $CHLD_W; 1555our $CHLD_W;
1124our $CHLD_DELAY_W; 1556our $CHLD_DELAY_W;
1125our $PID_IDLE;
1126our $WNOHANG; 1557our $WNOHANG;
1127 1558
1128sub _child_wait { 1559sub _emit_childstatus($$) {
1129 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1560 my (undef, $rpid, $rstatus) = @_;
1561
1562 $_->($rpid, $rstatus)
1130 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1563 for values %{ $PID_CB{$rpid} || {} },
1131 (values %{ $PID_CB{0} || {} }); 1564 values %{ $PID_CB{0} || {} };
1132 }
1133
1134 undef $PID_IDLE;
1135} 1565}
1136 1566
1137sub _sigchld { 1567sub _sigchld {
1138 # make sure we deliver these changes "synchronous" with the event loop. 1568 my $pid;
1139 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { 1569
1140 undef $CHLD_DELAY_W; 1570 AnyEvent->_emit_childstatus ($pid, $?)
1141 &_child_wait; 1571 while ($pid = waitpid -1, $WNOHANG) > 0;
1142 });
1143} 1572}
1144 1573
1145sub child { 1574sub child {
1146 my (undef, %arg) = @_; 1575 my (undef, %arg) = @_;
1147 1576
1148 defined (my $pid = $arg{pid} + 0) 1577 defined (my $pid = $arg{pid} + 0)
1149 or Carp::croak "required option 'pid' is missing"; 1578 or Carp::croak "required option 'pid' is missing";
1150 1579
1151 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1580 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1152 1581
1153 unless ($WNOHANG) { 1582 # WNOHANG is almost cetrainly 1 everywhere
1583 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1584 ? 1
1154 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1585 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1155 }
1156 1586
1157 unless ($CHLD_W) { 1587 unless ($CHLD_W) {
1158 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1588 $CHLD_W = AE::signal CHLD => \&_sigchld;
1159 # child could be a zombie already, so make at least one round 1589 # child could be a zombie already, so make at least one round
1160 &_sigchld; 1590 &_sigchld;
1161 } 1591 }
1162 1592
1163 bless [$pid, $arg{cb}], "AnyEvent::Base::Child" 1593 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1164} 1594}
1165 1595
1166sub AnyEvent::Base::Child::DESTROY { 1596sub AnyEvent::Base::child::DESTROY {
1167 my ($pid, $cb) = @{$_[0]}; 1597 my ($pid, $cb) = @{$_[0]};
1168 1598
1169 delete $PID_CB{$pid}{$cb}; 1599 delete $PID_CB{$pid}{$cb};
1170 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1600 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1171 1601
1172 undef $CHLD_W unless keys %PID_CB; 1602 undef $CHLD_W unless keys %PID_CB;
1173} 1603}
1174 1604
1605# idle emulation is done by simply using a timer, regardless
1606# of whether the process is idle or not, and not letting
1607# the callback use more than 50% of the time.
1608sub idle {
1609 my (undef, %arg) = @_;
1610
1611 my ($cb, $w, $rcb) = $arg{cb};
1612
1613 $rcb = sub {
1614 if ($cb) {
1615 $w = _time;
1616 &$cb;
1617 $w = _time - $w;
1618
1619 # never use more then 50% of the time for the idle watcher,
1620 # within some limits
1621 $w = 0.0001 if $w < 0.0001;
1622 $w = 5 if $w > 5;
1623
1624 $w = AE::timer $w, 0, $rcb;
1625 } else {
1626 # clean up...
1627 undef $w;
1628 undef $rcb;
1629 }
1630 };
1631
1632 $w = AE::timer 0.05, 0, $rcb;
1633
1634 bless \\$cb, "AnyEvent::Base::idle"
1635}
1636
1637sub AnyEvent::Base::idle::DESTROY {
1638 undef $${$_[0]};
1639}
1640
1175package AnyEvent::CondVar; 1641package AnyEvent::CondVar;
1176 1642
1177our @ISA = AnyEvent::CondVar::Base::; 1643our @ISA = AnyEvent::CondVar::Base::;
1178 1644
1179package AnyEvent::CondVar::Base; 1645package AnyEvent::CondVar::Base;
1180 1646
1181use overload 1647#use overload
1182 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1648# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1183 fallback => 1; 1649# fallback => 1;
1650
1651# save 300+ kilobytes by dirtily hardcoding overloading
1652${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1653*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1654*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1655${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1656
1657our $WAITING;
1184 1658
1185sub _send { 1659sub _send {
1186 # nop 1660 # nop
1187} 1661}
1188 1662
1201sub ready { 1675sub ready {
1202 $_[0]{_ae_sent} 1676 $_[0]{_ae_sent}
1203} 1677}
1204 1678
1205sub _wait { 1679sub _wait {
1680 $WAITING
1681 and !$_[0]{_ae_sent}
1682 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1683
1684 local $WAITING = 1;
1206 AnyEvent->one_event while !$_[0]{_ae_sent}; 1685 AnyEvent->one_event while !$_[0]{_ae_sent};
1207} 1686}
1208 1687
1209sub recv { 1688sub recv {
1210 $_[0]->_wait; 1689 $_[0]->_wait;
1212 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1691 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1213 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1692 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1214} 1693}
1215 1694
1216sub cb { 1695sub cb {
1217 $_[0]{_ae_cb} = $_[1] if @_ > 1; 1696 my $cv = shift;
1697
1698 @_
1699 and $cv->{_ae_cb} = shift
1700 and $cv->{_ae_sent}
1701 and (delete $cv->{_ae_cb})->($cv);
1702
1218 $_[0]{_ae_cb} 1703 $cv->{_ae_cb}
1219} 1704}
1220 1705
1221sub begin { 1706sub begin {
1222 ++$_[0]{_ae_counter}; 1707 ++$_[0]{_ae_counter};
1223 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1708 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1251so on. 1736so on.
1252 1737
1253=head1 ENVIRONMENT VARIABLES 1738=head1 ENVIRONMENT VARIABLES
1254 1739
1255The following environment variables are used by this module or its 1740The following environment variables are used by this module or its
1256submodules: 1741submodules.
1742
1743Note that AnyEvent will remove I<all> environment variables starting with
1744C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
1745enabled.
1257 1746
1258=over 4 1747=over 4
1259 1748
1260=item C<PERL_ANYEVENT_VERBOSE> 1749=item C<PERL_ANYEVENT_VERBOSE>
1261 1750
1268C<PERL_ANYEVENT_MODEL>. 1757C<PERL_ANYEVENT_MODEL>.
1269 1758
1270When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1759When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1271model it chooses. 1760model it chooses.
1272 1761
1762When set to C<8> or higher, then AnyEvent will report extra information on
1763which optional modules it loads and how it implements certain features.
1764
1273=item C<PERL_ANYEVENT_STRICT> 1765=item C<PERL_ANYEVENT_STRICT>
1274 1766
1275AnyEvent does not do much argument checking by default, as thorough 1767AnyEvent does not do much argument checking by default, as thorough
1276argument checking is very costly. Setting this variable to a true value 1768argument checking is very costly. Setting this variable to a true value
1277will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1769will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1278check the arguments passed to most method calls. If it finds any problems 1770check the arguments passed to most method calls. If it finds any problems,
1279it will croak. 1771it will croak.
1280 1772
1281In other words, enables "strict" mode. 1773In other words, enables "strict" mode.
1282 1774
1283Unlike C<use strict>, it is definitely recommended ot keep it off in 1775Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1284production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1776>>, it is definitely recommended to keep it off in production. Keeping
1285developing programs can be very useful, however. 1777C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1778can be very useful, however.
1286 1779
1287=item C<PERL_ANYEVENT_MODEL> 1780=item C<PERL_ANYEVENT_MODEL>
1288 1781
1289This can be used to specify the event model to be used by AnyEvent, before 1782This can be used to specify the event model to be used by AnyEvent, before
1290auto detection and -probing kicks in. It must be a string consisting 1783auto detection and -probing kicks in. It must be a string consisting
1333 1826
1334=item C<PERL_ANYEVENT_MAX_FORKS> 1827=item C<PERL_ANYEVENT_MAX_FORKS>
1335 1828
1336The maximum number of child processes that C<AnyEvent::Util::fork_call> 1829The maximum number of child processes that C<AnyEvent::Util::fork_call>
1337will create in parallel. 1830will create in parallel.
1831
1832=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1833
1834The default value for the C<max_outstanding> parameter for the default DNS
1835resolver - this is the maximum number of parallel DNS requests that are
1836sent to the DNS server.
1837
1838=item C<PERL_ANYEVENT_RESOLV_CONF>
1839
1840The file to use instead of F</etc/resolv.conf> (or OS-specific
1841configuration) in the default resolver. When set to the empty string, no
1842default config will be used.
1843
1844=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1845
1846When neither C<ca_file> nor C<ca_path> was specified during
1847L<AnyEvent::TLS> context creation, and either of these environment
1848variables exist, they will be used to specify CA certificate locations
1849instead of a system-dependent default.
1850
1851=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1852
1853When these are set to C<1>, then the respective modules are not
1854loaded. Mostly good for testing AnyEvent itself.
1338 1855
1339=back 1856=back
1340 1857
1341=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1858=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1342 1859
1400 warn "read: $input\n"; # output what has been read 1917 warn "read: $input\n"; # output what has been read
1401 $cv->send if $input =~ /^q/i; # quit program if /^q/i 1918 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1402 }, 1919 },
1403 ); 1920 );
1404 1921
1405 my $time_watcher; # can only be used once
1406
1407 sub new_timer {
1408 $timer = AnyEvent->timer (after => 1, cb => sub { 1922 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1409 warn "timeout\n"; # print 'timeout' about every second 1923 warn "timeout\n"; # print 'timeout' at most every second
1410 &new_timer; # and restart the time
1411 }); 1924 });
1412 }
1413
1414 new_timer; # create first timer
1415 1925
1416 $cv->recv; # wait until user enters /^q/i 1926 $cv->recv; # wait until user enters /^q/i
1417 1927
1418=head1 REAL-WORLD EXAMPLE 1928=head1 REAL-WORLD EXAMPLE
1419 1929
1550through AnyEvent. The benchmark creates a lot of timers (with a zero 2060through AnyEvent. The benchmark creates a lot of timers (with a zero
1551timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2061timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1552which it is), lets them fire exactly once and destroys them again. 2062which it is), lets them fire exactly once and destroys them again.
1553 2063
1554Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2064Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1555distribution. 2065distribution. It uses the L<AE> interface, which makes a real difference
2066for the EV and Perl backends only.
1556 2067
1557=head3 Explanation of the columns 2068=head3 Explanation of the columns
1558 2069
1559I<watcher> is the number of event watchers created/destroyed. Since 2070I<watcher> is the number of event watchers created/destroyed. Since
1560different event models feature vastly different performances, each event 2071different event models feature vastly different performances, each event
1581watcher. 2092watcher.
1582 2093
1583=head3 Results 2094=head3 Results
1584 2095
1585 name watchers bytes create invoke destroy comment 2096 name watchers bytes create invoke destroy comment
1586 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2097 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1587 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2098 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1588 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2099 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1589 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2100 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1590 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2101 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1591 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2102 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2103 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2104 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1592 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2105 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1593 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2106 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1594 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2107 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1595 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2108 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1596 2109
1597=head3 Discussion 2110=head3 Discussion
1598 2111
1599The benchmark does I<not> measure scalability of the event loop very 2112The benchmark does I<not> measure scalability of the event loop very
1600well. For example, a select-based event loop (such as the pure perl one) 2113well. For example, a select-based event loop (such as the pure perl one)
1612benchmark machine, handling an event takes roughly 1600 CPU cycles with 2125benchmark machine, handling an event takes roughly 1600 CPU cycles with
1613EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2126EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1614cycles with POE. 2127cycles with POE.
1615 2128
1616C<EV> is the sole leader regarding speed and memory use, which are both 2129C<EV> is the sole leader regarding speed and memory use, which are both
1617maximal/minimal, respectively. Even when going through AnyEvent, it uses 2130maximal/minimal, respectively. When using the L<AE> API there is zero
2131overhead (when going through the AnyEvent API create is about 5-6 times
2132slower, with other times being equal, so still uses far less memory than
1618far less memory than any other event loop and is still faster than Event 2133any other event loop and is still faster than Event natively).
1619natively.
1620 2134
1621The pure perl implementation is hit in a few sweet spots (both the 2135The pure perl implementation is hit in a few sweet spots (both the
1622constant timeout and the use of a single fd hit optimisations in the perl 2136constant timeout and the use of a single fd hit optimisations in the perl
1623interpreter and the backend itself). Nevertheless this shows that it 2137interpreter and the backend itself). Nevertheless this shows that it
1624adds very little overhead in itself. Like any select-based backend its 2138adds very little overhead in itself. Like any select-based backend its
1625performance becomes really bad with lots of file descriptors (and few of 2139performance becomes really bad with lots of file descriptors (and few of
1626them active), of course, but this was not subject of this benchmark. 2140them active), of course, but this was not subject of this benchmark.
1627 2141
1628The C<Event> module has a relatively high setup and callback invocation 2142The C<Event> module has a relatively high setup and callback invocation
1629cost, but overall scores in on the third place. 2143cost, but overall scores in on the third place.
2144
2145C<IO::Async> performs admirably well, about on par with C<Event>, even
2146when using its pure perl backend.
1630 2147
1631C<Glib>'s memory usage is quite a bit higher, but it features a 2148C<Glib>'s memory usage is quite a bit higher, but it features a
1632faster callback invocation and overall ends up in the same class as 2149faster callback invocation and overall ends up in the same class as
1633C<Event>. However, Glib scales extremely badly, doubling the number of 2150C<Event>. However, Glib scales extremely badly, doubling the number of
1634watchers increases the processing time by more than a factor of four, 2151watchers increases the processing time by more than a factor of four,
1695In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2212In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1696(1%) are active. This mirrors the activity of large servers with many 2213(1%) are active. This mirrors the activity of large servers with many
1697connections, most of which are idle at any one point in time. 2214connections, most of which are idle at any one point in time.
1698 2215
1699Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2216Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1700distribution. 2217distribution. It uses the L<AE> interface, which makes a real difference
2218for the EV and Perl backends only.
1701 2219
1702=head3 Explanation of the columns 2220=head3 Explanation of the columns
1703 2221
1704I<sockets> is the number of sockets, and twice the number of "servers" (as 2222I<sockets> is the number of sockets, and twice the number of "servers" (as
1705each server has a read and write socket end). 2223each server has a read and write socket end).
1712it to another server. This includes deleting the old timeout and creating 2230it to another server. This includes deleting the old timeout and creating
1713a new one that moves the timeout into the future. 2231a new one that moves the timeout into the future.
1714 2232
1715=head3 Results 2233=head3 Results
1716 2234
1717 name sockets create request 2235 name sockets create request
1718 EV 20000 69.01 11.16 2236 EV 20000 62.66 7.99
1719 Perl 20000 73.32 35.87 2237 Perl 20000 68.32 32.64
1720 Event 20000 212.62 257.32 2238 IOAsync 20000 174.06 101.15 epoll
1721 Glib 20000 651.16 1896.30 2239 IOAsync 20000 174.67 610.84 poll
2240 Event 20000 202.69 242.91
2241 Glib 20000 557.01 1689.52
1722 POE 20000 349.67 12317.24 uses POE::Loop::Event 2242 POE 20000 341.54 12086.32 uses POE::Loop::Event
1723 2243
1724=head3 Discussion 2244=head3 Discussion
1725 2245
1726This benchmark I<does> measure scalability and overall performance of the 2246This benchmark I<does> measure scalability and overall performance of the
1727particular event loop. 2247particular event loop.
1729EV is again fastest. Since it is using epoll on my system, the setup time 2249EV is again fastest. Since it is using epoll on my system, the setup time
1730is relatively high, though. 2250is relatively high, though.
1731 2251
1732Perl surprisingly comes second. It is much faster than the C-based event 2252Perl surprisingly comes second. It is much faster than the C-based event
1733loops Event and Glib. 2253loops Event and Glib.
2254
2255IO::Async performs very well when using its epoll backend, and still quite
2256good compared to Glib when using its pure perl backend.
1734 2257
1735Event suffers from high setup time as well (look at its code and you will 2258Event suffers from high setup time as well (look at its code and you will
1736understand why). Callback invocation also has a high overhead compared to 2259understand why). Callback invocation also has a high overhead compared to
1737the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 2260the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1738uses select or poll in basically all documented configurations. 2261uses select or poll in basically all documented configurations.
1801=item * C-based event loops perform very well with small number of 2324=item * C-based event loops perform very well with small number of
1802watchers, as the management overhead dominates. 2325watchers, as the management overhead dominates.
1803 2326
1804=back 2327=back
1805 2328
2329=head2 THE IO::Lambda BENCHMARK
2330
2331Recently I was told about the benchmark in the IO::Lambda manpage, which
2332could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
2333simply compares IO::Lambda with POE, and IO::Lambda looks better (which
2334shouldn't come as a surprise to anybody). As such, the benchmark is
2335fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
2336very optimal. But how would AnyEvent compare when used without the extra
2337baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
2338
2339The benchmark itself creates an echo-server, and then, for 500 times,
2340connects to the echo server, sends a line, waits for the reply, and then
2341creates the next connection. This is a rather bad benchmark, as it doesn't
2342test the efficiency of the framework or much non-blocking I/O, but it is a
2343benchmark nevertheless.
2344
2345 name runtime
2346 Lambda/select 0.330 sec
2347 + optimized 0.122 sec
2348 Lambda/AnyEvent 0.327 sec
2349 + optimized 0.138 sec
2350 Raw sockets/select 0.077 sec
2351 POE/select, components 0.662 sec
2352 POE/select, raw sockets 0.226 sec
2353 POE/select, optimized 0.404 sec
2354
2355 AnyEvent/select/nb 0.085 sec
2356 AnyEvent/EV/nb 0.068 sec
2357 +state machine 0.134 sec
2358
2359The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
2360benchmarks actually make blocking connects and use 100% blocking I/O,
2361defeating the purpose of an event-based solution. All of the newly
2362written AnyEvent benchmarks use 100% non-blocking connects (using
2363AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
2364resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
2365generally require a lot more bookkeeping and event handling than blocking
2366connects (which involve a single syscall only).
2367
2368The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
2369offers similar expressive power as POE and IO::Lambda, using conventional
2370Perl syntax. This means that both the echo server and the client are 100%
2371non-blocking, further placing it at a disadvantage.
2372
2373As you can see, the AnyEvent + EV combination even beats the
2374hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2375backend easily beats IO::Lambda and POE.
2376
2377And even the 100% non-blocking version written using the high-level (and
2378slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2379higher level ("unoptimised") abstractions by a large margin, even though
2380it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2381
2382The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2383F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2384part of the IO::Lambda distribution and were used without any changes.
2385
1806 2386
1807=head1 SIGNALS 2387=head1 SIGNALS
1808 2388
1809AnyEvent currently installs handlers for these signals: 2389AnyEvent currently installs handlers for these signals:
1810 2390
1813=item SIGCHLD 2393=item SIGCHLD
1814 2394
1815A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2395A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1816emulation for event loops that do not support them natively. Also, some 2396emulation for event loops that do not support them natively. Also, some
1817event loops install a similar handler. 2397event loops install a similar handler.
2398
2399Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2400AnyEvent will reset it to default, to avoid losing child exit statuses.
1818 2401
1819=item SIGPIPE 2402=item SIGPIPE
1820 2403
1821A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2404A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1822when AnyEvent gets loaded. 2405when AnyEvent gets loaded.
1834 2417
1835=back 2418=back
1836 2419
1837=cut 2420=cut
1838 2421
2422undef $SIG{CHLD}
2423 if $SIG{CHLD} eq 'IGNORE';
2424
1839$SIG{PIPE} = sub { } 2425$SIG{PIPE} = sub { }
1840 unless defined $SIG{PIPE}; 2426 unless defined $SIG{PIPE};
2427
2428=head1 RECOMMENDED/OPTIONAL MODULES
2429
2430One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2431it's built-in modules) are required to use it.
2432
2433That does not mean that AnyEvent won't take advantage of some additional
2434modules if they are installed.
2435
2436This section epxlains which additional modules will be used, and how they
2437affect AnyEvent's operetion.
2438
2439=over 4
2440
2441=item L<Async::Interrupt>
2442
2443This slightly arcane module is used to implement fast signal handling: To
2444my knowledge, there is no way to do completely race-free and quick
2445signal handling in pure perl. To ensure that signals still get
2446delivered, AnyEvent will start an interval timer to wake up perl (and
2447catch the signals) with some delay (default is 10 seconds, look for
2448C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2449
2450If this module is available, then it will be used to implement signal
2451catching, which means that signals will not be delayed, and the event loop
2452will not be interrupted regularly, which is more efficient (And good for
2453battery life on laptops).
2454
2455This affects not just the pure-perl event loop, but also other event loops
2456that have no signal handling on their own (e.g. Glib, Tk, Qt).
2457
2458Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2459and either employ their own workarounds (POE) or use AnyEvent's workaround
2460(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2461does nothing for those backends.
2462
2463=item L<EV>
2464
2465This module isn't really "optional", as it is simply one of the backend
2466event loops that AnyEvent can use. However, it is simply the best event
2467loop available in terms of features, speed and stability: It supports
2468the AnyEvent API optimally, implements all the watcher types in XS, does
2469automatic timer adjustments even when no monotonic clock is available,
2470can take avdantage of advanced kernel interfaces such as C<epoll> and
2471C<kqueue>, and is the fastest backend I<by far>. You can even embed
2472L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2473
2474=item L<Guard>
2475
2476The guard module, when used, will be used to implement
2477C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2478lot less memory), but otherwise doesn't affect guard operation much. It is
2479purely used for performance.
2480
2481=item L<JSON> and L<JSON::XS>
2482
2483One of these modules is required when you want to read or write JSON data
2484via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2485advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2486
2487In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2488installed.
2489
2490=item L<Net::SSLeay>
2491
2492Implementing TLS/SSL in Perl is certainly interesting, but not very
2493worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2494the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2495
2496=item L<Time::HiRes>
2497
2498This module is part of perl since release 5.008. It will be used when the
2499chosen event library does not come with a timing source on it's own. The
2500pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2501try to use a monotonic clock for timing stability.
2502
2503=back
1841 2504
1842 2505
1843=head1 FORK 2506=head1 FORK
1844 2507
1845Most event libraries are not fork-safe. The ones who are usually are 2508Most event libraries are not fork-safe. The ones who are usually are
1846because they rely on inefficient but fork-safe C<select> or C<poll> 2509because they rely on inefficient but fork-safe C<select> or C<poll>
1847calls. Only L<EV> is fully fork-aware. 2510calls. Only L<EV> is fully fork-aware.
1848 2511
1849If you have to fork, you must either do so I<before> creating your first 2512If you have to fork, you must either do so I<before> creating your first
1850watcher OR you must not use AnyEvent at all in the child. 2513watcher OR you must not use AnyEvent at all in the child OR you must do
2514something completely out of the scope of AnyEvent.
1851 2515
1852 2516
1853=head1 SECURITY CONSIDERATIONS 2517=head1 SECURITY CONSIDERATIONS
1854 2518
1855AnyEvent can be forced to load any event model via 2519AnyEvent can be forced to load any event model via
1867 use AnyEvent; 2531 use AnyEvent;
1868 2532
1869Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2533Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1870be used to probe what backend is used and gain other information (which is 2534be used to probe what backend is used and gain other information (which is
1871probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2535probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1872$ENV{PERL_ANYEGENT_STRICT}. 2536$ENV{PERL_ANYEVENT_STRICT}.
2537
2538Note that AnyEvent will remove I<all> environment variables starting with
2539C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2540enabled.
1873 2541
1874 2542
1875=head1 BUGS 2543=head1 BUGS
1876 2544
1877Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2545Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1889L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2557L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1890 2558
1891Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2559Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1892L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2560L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1893L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2561L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1894L<AnyEvent::Impl::POE>. 2562L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1895 2563
1896Non-blocking file handles, sockets, TCP clients and 2564Non-blocking file handles, sockets, TCP clients and
1897servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2565servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1898 2566
1899Asynchronous DNS: L<AnyEvent::DNS>. 2567Asynchronous DNS: L<AnyEvent::DNS>.
1900 2568
1901Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2569Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2570L<Coro::Event>,
1902 2571
1903Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2572Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2573L<AnyEvent::HTTP>.
1904 2574
1905 2575
1906=head1 AUTHOR 2576=head1 AUTHOR
1907 2577
1908 Marc Lehmann <schmorp@schmorp.de> 2578 Marc Lehmann <schmorp@schmorp.de>

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