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Revision 1.180 by root, Sat Sep 6 07:00:45 2008 UTC vs.
Revision 1.241 by root, Fri Jul 17 18:08:35 2009 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
6event loops.
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 $condvar gets ->send
29 # use a condvar in callback mode: 37 # use a condvar in callback mode:
137These watchers are normal Perl objects with normal Perl lifetime. After 145These watchers are normal Perl objects with normal Perl lifetime. After
138creating a watcher it will immediately "watch" for events and invoke the 146creating a watcher it will immediately "watch" for events and invoke the
139callback when the event occurs (of course, only when the event model 147callback when the event occurs (of course, only when the event model
140is in control). 148is in control).
141 149
150Note that B<callbacks must not permanently change global variables>
151potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152callbacks must not C<die> >>. The former is good programming practise in
153Perl and the latter stems from the fact that exception handling differs
154widely between event loops.
155
142To disable the watcher you have to destroy it (e.g. by setting the 156To disable the watcher you have to destroy it (e.g. by setting the
143variable you store it in to C<undef> or otherwise deleting all references 157variable you store it in to C<undef> or otherwise deleting all references
144to it). 158to it).
145 159
146All watchers are created by calling a method on the C<AnyEvent> class. 160All watchers are created by calling a method on the C<AnyEvent> class.
162=head2 I/O WATCHERS 176=head2 I/O WATCHERS
163 177
164You can create an I/O watcher by calling the C<< AnyEvent->io >> method 178You can create an I/O watcher by calling the C<< AnyEvent->io >> method
165with the following mandatory key-value pairs as arguments: 179with the following mandatory key-value pairs as arguments:
166 180
167C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events 181C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
168(AnyEvent might or might not keep a reference to this file handle). C<poll> 182for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files
186or block devices.
187
169must be a string that is either C<r> or C<w>, which creates a watcher 188C<poll> must be a string that is either C<r> or C<w>, which creates a
170waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the 189watcher waiting for "r"eadable or "w"ritable events, respectively.
190
171callback to invoke each time the file handle becomes ready. 191C<cb> is the callback to invoke each time the file handle becomes ready.
172 192
173Although the callback might get passed parameters, their value and 193Although the callback might get passed parameters, their value and
174presence is undefined and you cannot rely on them. Portable AnyEvent 194presence is undefined and you cannot rely on them. Portable AnyEvent
175callbacks cannot use arguments passed to I/O watcher callbacks. 195callbacks cannot use arguments passed to I/O watcher callbacks.
176 196
308In either case, if you care (and in most cases, you don't), then you 328In either case, if you care (and in most cases, you don't), then you
309can get whatever behaviour you want with any event loop, by taking the 329can get whatever behaviour you want with any event loop, by taking the
310difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 330difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311account. 331account.
312 332
333=item AnyEvent->now_update
334
335Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
336the current time for each loop iteration (see the discussion of L<<
337AnyEvent->now >>, above).
338
339When a callback runs for a long time (or when the process sleeps), then
340this "current" time will differ substantially from the real time, which
341might affect timers and time-outs.
342
343When this is the case, you can call this method, which will update the
344event loop's idea of "current time".
345
346Note that updating the time I<might> cause some events to be handled.
347
313=back 348=back
314 349
315=head2 SIGNAL WATCHERS 350=head2 SIGNAL WATCHERS
316 351
317You can watch for signals using a signal watcher, C<signal> is the signal 352You can watch for signals using a signal watcher, C<signal> is the signal
340=head2 CHILD PROCESS WATCHERS 375=head2 CHILD PROCESS WATCHERS
341 376
342You can also watch on a child process exit and catch its exit status. 377You can also watch on a child process exit and catch its exit status.
343 378
344The child process is specified by the C<pid> argument (if set to C<0>, it 379The child process is specified by the C<pid> argument (if set to C<0>, it
345watches for any child process exit). The watcher will trigger as often 380watches for any child process exit). The watcher will triggered only when
346as status change for the child are received. This works by installing a 381the child process has finished and an exit status is available, not on
347signal handler for C<SIGCHLD>. The callback will be called with the pid 382any trace events (stopped/continued).
348and exit status (as returned by waitpid), so unlike other watcher types, 383
349you I<can> rely on child watcher callback arguments. 384The callback will be called with the pid and exit status (as returned by
385waitpid), so unlike other watcher types, you I<can> rely on child watcher
386callback arguments.
387
388This watcher type works by installing a signal handler for C<SIGCHLD>,
389and since it cannot be shared, nothing else should use SIGCHLD or reap
390random child processes (waiting for specific child processes, e.g. inside
391C<system>, is just fine).
350 392
351There is a slight catch to child watchers, however: you usually start them 393There is a slight catch to child watchers, however: you usually start them
352I<after> the child process was created, and this means the process could 394I<after> the child process was created, and this means the process could
353have exited already (and no SIGCHLD will be sent anymore). 395have exited already (and no SIGCHLD will be sent anymore).
354 396
355Not all event models handle this correctly (POE doesn't), but even for 397Not all event models handle this correctly (neither POE nor IO::Async do,
398see their AnyEvent::Impl manpages for details), but even for event models
356event models that I<do> handle this correctly, they usually need to be 399that I<do> handle this correctly, they usually need to be loaded before
357loaded before the process exits (i.e. before you fork in the first place). 400the process exits (i.e. before you fork in the first place). AnyEvent's
401pure perl event loop handles all cases correctly regardless of when you
402start the watcher.
358 403
359This means you cannot create a child watcher as the very first thing in an 404This means you cannot create a child watcher as the very first
360AnyEvent program, you I<have> to create at least one watcher before you 405thing in an AnyEvent program, you I<have> to create at least one
361C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 406watcher before you C<fork> the child (alternatively, you can call
407C<AnyEvent::detect>).
362 408
363Example: fork a process and wait for it 409Example: fork a process and wait for it
364 410
365 my $done = AnyEvent->condvar; 411 my $done = AnyEvent->condvar;
366 412
376 ); 422 );
377 423
378 # do something else, then wait for process exit 424 # do something else, then wait for process exit
379 $done->recv; 425 $done->recv;
380 426
427=head2 IDLE WATCHERS
428
429Sometimes there is a need to do something, but it is not so important
430to do it instantly, but only when there is nothing better to do. This
431"nothing better to do" is usually defined to be "no other events need
432attention by the event loop".
433
434Idle watchers ideally get invoked when the event loop has nothing
435better to do, just before it would block the process to wait for new
436events. Instead of blocking, the idle watcher is invoked.
437
438Most event loops unfortunately do not really support idle watchers (only
439EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440will simply call the callback "from time to time".
441
442Example: read lines from STDIN, but only process them when the
443program is otherwise idle:
444
445 my @lines; # read data
446 my $idle_w;
447 my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
448 push @lines, scalar <STDIN>;
449
450 # start an idle watcher, if not already done
451 $idle_w ||= AnyEvent->idle (cb => sub {
452 # handle only one line, when there are lines left
453 if (my $line = shift @lines) {
454 print "handled when idle: $line";
455 } else {
456 # otherwise disable the idle watcher again
457 undef $idle_w;
458 }
459 });
460 });
461
381=head2 CONDITION VARIABLES 462=head2 CONDITION VARIABLES
382 463
383If you are familiar with some event loops you will know that all of them 464If you are familiar with some event loops you will know that all of them
384require you to run some blocking "loop", "run" or similar function that 465require you to run some blocking "loop", "run" or similar function that
385will actively watch for new events and call your callbacks. 466will actively watch for new events and call your callbacks.
386 467
387AnyEvent is different, it expects somebody else to run the event loop and 468AnyEvent is slightly different: it expects somebody else to run the event
388will only block when necessary (usually when told by the user). 469loop and will only block when necessary (usually when told by the user).
389 470
390The instrument to do that is called a "condition variable", so called 471The instrument to do that is called a "condition variable", so called
391because they represent a condition that must become true. 472because they represent a condition that must become true.
392 473
474Now is probably a good time to look at the examples further below.
475
393Condition variables can be created by calling the C<< AnyEvent->condvar 476Condition variables can be created by calling the C<< AnyEvent->condvar
394>> method, usually without arguments. The only argument pair allowed is 477>> method, usually without arguments. The only argument pair allowed is
395
396C<cb>, which specifies a callback to be called when the condition variable 478C<cb>, which specifies a callback to be called when the condition variable
397becomes true, with the condition variable as the first argument (but not 479becomes true, with the condition variable as the first argument (but not
398the results). 480the results).
399 481
400After creation, the condition variable is "false" until it becomes "true" 482After creation, the condition variable is "false" until it becomes "true"
449 after => 1, 531 after => 1,
450 cb => sub { $result_ready->send }, 532 cb => sub { $result_ready->send },
451 ); 533 );
452 534
453 # this "blocks" (while handling events) till the callback 535 # this "blocks" (while handling events) till the callback
454 # calls send 536 # calls -<send
455 $result_ready->recv; 537 $result_ready->recv;
456 538
457Example: wait for a timer, but take advantage of the fact that 539Example: wait for a timer, but take advantage of the fact that condition
458condition variables are also code references. 540variables are also callable directly.
459 541
460 my $done = AnyEvent->condvar; 542 my $done = AnyEvent->condvar;
461 my $delay = AnyEvent->timer (after => 5, cb => $done); 543 my $delay = AnyEvent->timer (after => 5, cb => $done);
462 $done->recv; 544 $done->recv;
463 545
469 551
470 ... 552 ...
471 553
472 my @info = $couchdb->info->recv; 554 my @info = $couchdb->info->recv;
473 555
474And this is how you would just ste a callback to be called whenever the 556And this is how you would just set a callback to be called whenever the
475results are available: 557results are available:
476 558
477 $couchdb->info->cb (sub { 559 $couchdb->info->cb (sub {
478 my @info = $_[0]->recv; 560 my @info = $_[0]->recv;
479 }); 561 });
497immediately from within send. 579immediately from within send.
498 580
499Any arguments passed to the C<send> call will be returned by all 581Any arguments passed to the C<send> call will be returned by all
500future C<< ->recv >> calls. 582future C<< ->recv >> calls.
501 583
502Condition variables are overloaded so one can call them directly 584Condition variables are overloaded so one can call them directly (as if
503(as a code reference). Calling them directly is the same as calling 585they were a code reference). Calling them directly is the same as calling
504C<send>. Note, however, that many C-based event loops do not handle 586C<send>.
505overloading, so as tempting as it may be, passing a condition variable
506instead of a callback does not work. Both the pure perl and EV loops
507support overloading, however, as well as all functions that use perl to
508invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
509example).
510 587
511=item $cv->croak ($error) 588=item $cv->croak ($error)
512 589
513Similar to send, but causes all call's to C<< ->recv >> to invoke 590Similar to send, but causes all call's to C<< ->recv >> to invoke
514C<Carp::croak> with the given error message/object/scalar. 591C<Carp::croak> with the given error message/object/scalar.
515 592
516This can be used to signal any errors to the condition variable 593This can be used to signal any errors to the condition variable
517user/consumer. 594user/consumer. Doing it this way instead of calling C<croak> directly
595delays the error detetcion, but has the overwhelmign advantage that it
596diagnoses the error at the place where the result is expected, and not
597deep in some event clalback without connection to the actual code causing
598the problem.
518 599
519=item $cv->begin ([group callback]) 600=item $cv->begin ([group callback])
520 601
521=item $cv->end 602=item $cv->end
522
523These two methods are EXPERIMENTAL and MIGHT CHANGE.
524 603
525These two methods can be used to combine many transactions/events into 604These two methods can be used to combine many transactions/events into
526one. For example, a function that pings many hosts in parallel might want 605one. For example, a function that pings many hosts in parallel might want
527to use a condition variable for the whole process. 606to use a condition variable for the whole process.
528 607
530C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 609C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
531>>, the (last) callback passed to C<begin> will be executed. That callback 610>>, the (last) callback passed to C<begin> will be executed. That callback
532is I<supposed> to call C<< ->send >>, but that is not required. If no 611is I<supposed> to call C<< ->send >>, but that is not required. If no
533callback was set, C<send> will be called without any arguments. 612callback was set, C<send> will be called without any arguments.
534 613
535Let's clarify this with the ping example: 614You can think of C<< $cv->send >> giving you an OR condition (one call
615sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617
618Let's start with a simple example: you have two I/O watchers (for example,
619STDOUT and STDERR for a program), and you want to wait for both streams to
620close before activating a condvar:
621
622 my $cv = AnyEvent->condvar;
623
624 $cv->begin; # first watcher
625 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
626 defined sysread $fh1, my $buf, 4096
627 or $cv->end;
628 });
629
630 $cv->begin; # second watcher
631 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
632 defined sysread $fh2, my $buf, 4096
633 or $cv->end;
634 });
635
636 $cv->recv;
637
638This works because for every event source (EOF on file handle), there is
639one call to C<begin>, so the condvar waits for all calls to C<end> before
640sending.
641
642The ping example mentioned above is slightly more complicated, as the
643there are results to be passwd back, and the number of tasks that are
644begung can potentially be zero:
536 645
537 my $cv = AnyEvent->condvar; 646 my $cv = AnyEvent->condvar;
538 647
539 my %result; 648 my %result;
540 $cv->begin (sub { $cv->send (\%result) }); 649 $cv->begin (sub { $cv->send (\%result) });
560loop, which serves two important purposes: first, it sets the callback 669loop, which serves two important purposes: first, it sets the callback
561to be called once the counter reaches C<0>, and second, it ensures that 670to be called once the counter reaches C<0>, and second, it ensures that
562C<send> is called even when C<no> hosts are being pinged (the loop 671C<send> is called even when C<no> hosts are being pinged (the loop
563doesn't execute once). 672doesn't execute once).
564 673
565This is the general pattern when you "fan out" into multiple subrequests: 674This is the general pattern when you "fan out" into multiple (but
566use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 675potentially none) subrequests: use an outer C<begin>/C<end> pair to set
567is called at least once, and then, for each subrequest you start, call 676the callback and ensure C<end> is called at least once, and then, for each
568C<begin> and for each subrequest you finish, call C<end>. 677subrequest you start, call C<begin> and for each subrequest you finish,
678call C<end>.
569 679
570=back 680=back
571 681
572=head3 METHODS FOR CONSUMERS 682=head3 METHODS FOR CONSUMERS
573 683
589function will call C<croak>. 699function will call C<croak>.
590 700
591In list context, all parameters passed to C<send> will be returned, 701In list context, all parameters passed to C<send> will be returned,
592in scalar context only the first one will be returned. 702in scalar context only the first one will be returned.
593 703
704Note that doing a blocking wait in a callback is not supported by any
705event loop, that is, recursive invocation of a blocking C<< ->recv
706>> is not allowed, and the C<recv> call will C<croak> if such a
707condition is detected. This condition can be slightly loosened by using
708L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
709any thread that doesn't run the event loop itself.
710
594Not all event models support a blocking wait - some die in that case 711Not all event models support a blocking wait - some die in that case
595(programs might want to do that to stay interactive), so I<if you are 712(programs might want to do that to stay interactive), so I<if you are
596using this from a module, never require a blocking wait>, but let the 713using this from a module, never require a blocking wait>. Instead, let the
597caller decide whether the call will block or not (for example, by coupling 714caller decide whether the call will block or not (for example, by coupling
598condition variables with some kind of request results and supporting 715condition variables with some kind of request results and supporting
599callbacks so the caller knows that getting the result will not block, 716callbacks so the caller knows that getting the result will not block,
600while still supporting blocking waits if the caller so desires). 717while still supporting blocking waits if the caller so desires).
601 718
602Another reason I<never> to C<< ->recv >> in a module is that you cannot
603sensibly have two C<< ->recv >>'s in parallel, as that would require
604multiple interpreters or coroutines/threads, none of which C<AnyEvent>
605can supply.
606
607The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
608fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
609versions and also integrates coroutines into AnyEvent, making blocking
610C<< ->recv >> calls perfectly safe as long as they are done from another
611coroutine (one that doesn't run the event loop).
612
613You can ensure that C<< -recv >> never blocks by setting a callback and 719You can ensure that C<< -recv >> never blocks by setting a callback and
614only calling C<< ->recv >> from within that callback (or at a later 720only calling C<< ->recv >> from within that callback (or at a later
615time). This will work even when the event loop does not support blocking 721time). This will work even when the event loop does not support blocking
616waits otherwise. 722waits otherwise.
617 723
630variable itself. Calling C<recv> inside the callback or at any later time 736variable itself. Calling C<recv> inside the callback or at any later time
631is guaranteed not to block. 737is guaranteed not to block.
632 738
633=back 739=back
634 740
741=head1 SUPPORTED EVENT LOOPS/BACKENDS
742
743The available backend classes are (every class has its own manpage):
744
745=over 4
746
747=item Backends that are autoprobed when no other event loop can be found.
748
749EV is the preferred backend when no other event loop seems to be in
750use. If EV is not installed, then AnyEvent will try Event, and, failing
751that, will fall back to its own pure-perl implementation, which is
752available everywhere as it comes with AnyEvent itself.
753
754 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
755 AnyEvent::Impl::Event based on Event, very stable, few glitches.
756 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
757
758=item Backends that are transparently being picked up when they are used.
759
760These will be used when they are currently loaded when the first watcher
761is created, in which case it is assumed that the application is using
762them. This means that AnyEvent will automatically pick the right backend
763when the main program loads an event module before anything starts to
764create watchers. Nothing special needs to be done by the main program.
765
766 AnyEvent::Impl::Glib based on Glib, slow but very stable.
767 AnyEvent::Impl::Tk based on Tk, very broken.
768 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
769 AnyEvent::Impl::POE based on POE, very slow, some limitations.
770
771=item Backends with special needs.
772
773Qt requires the Qt::Application to be instantiated first, but will
774otherwise be picked up automatically. As long as the main program
775instantiates the application before any AnyEvent watchers are created,
776everything should just work.
777
778 AnyEvent::Impl::Qt based on Qt.
779
780Support for IO::Async can only be partial, as it is too broken and
781architecturally limited to even support the AnyEvent API. It also
782is the only event loop that needs the loop to be set explicitly, so
783it can only be used by a main program knowing about AnyEvent. See
784L<AnyEvent::Impl::Async> for the gory details.
785
786 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
787
788=item Event loops that are indirectly supported via other backends.
789
790Some event loops can be supported via other modules:
791
792There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
793
794B<WxWidgets> has no support for watching file handles. However, you can
795use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
796polls 20 times per second, which was considered to be too horrible to even
797consider for AnyEvent.
798
799B<Prima> is not supported as nobody seems to be using it, but it has a POE
800backend, so it can be supported through POE.
801
802AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
803load L<POE> when detecting them, in the hope that POE will pick them up,
804in which case everything will be automatic.
805
806=back
807
635=head1 GLOBAL VARIABLES AND FUNCTIONS 808=head1 GLOBAL VARIABLES AND FUNCTIONS
636 809
810These are not normally required to use AnyEvent, but can be useful to
811write AnyEvent extension modules.
812
637=over 4 813=over 4
638 814
639=item $AnyEvent::MODEL 815=item $AnyEvent::MODEL
640 816
641Contains C<undef> until the first watcher is being created. Then it 817Contains C<undef> until the first watcher is being created, before the
818backend has been autodetected.
819
642contains the event model that is being used, which is the name of the 820Afterwards it contains the event model that is being used, which is the
643Perl class implementing the model. This class is usually one of the 821name of the Perl class implementing the model. This class is usually one
644C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 822of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
645AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 823case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
646 824will be C<urxvt::anyevent>).
647The known classes so far are:
648
649 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
650 AnyEvent::Impl::Event based on Event, second best choice.
651 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
652 AnyEvent::Impl::Glib based on Glib, third-best choice.
653 AnyEvent::Impl::Tk based on Tk, very bad choice.
654 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
655 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
656 AnyEvent::Impl::POE based on POE, not generic enough for full support.
657
658There is no support for WxWidgets, as WxWidgets has no support for
659watching file handles. However, you can use WxWidgets through the
660POE Adaptor, as POE has a Wx backend that simply polls 20 times per
661second, which was considered to be too horrible to even consider for
662AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
663it's adaptor.
664
665AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
666autodetecting them.
667 825
668=item AnyEvent::detect 826=item AnyEvent::detect
669 827
670Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 828Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
671if necessary. You should only call this function right before you would 829if necessary. You should only call this function right before you would
672have created an AnyEvent watcher anyway, that is, as late as possible at 830have created an AnyEvent watcher anyway, that is, as late as possible at
673runtime. 831runtime, and not e.g. while initialising of your module.
832
833If you need to do some initialisation before AnyEvent watchers are
834created, use C<post_detect>.
674 835
675=item $guard = AnyEvent::post_detect { BLOCK } 836=item $guard = AnyEvent::post_detect { BLOCK }
676 837
677Arranges for the code block to be executed as soon as the event model is 838Arranges for the code block to be executed as soon as the event model is
678autodetected (or immediately if this has already happened). 839autodetected (or immediately if this has already happened).
840
841The block will be executed I<after> the actual backend has been detected
842(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
843created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
844other initialisations - see the sources of L<AnyEvent::Strict> or
845L<AnyEvent::AIO> to see how this is used.
846
847The most common usage is to create some global watchers, without forcing
848event module detection too early, for example, L<AnyEvent::AIO> creates
849and installs the global L<IO::AIO> watcher in a C<post_detect> block to
850avoid autodetecting the event module at load time.
679 851
680If called in scalar or list context, then it creates and returns an object 852If called in scalar or list context, then it creates and returns an object
681that automatically removes the callback again when it is destroyed. See 853that automatically removes the callback again when it is destroyed. See
682L<Coro::BDB> for a case where this is useful. 854L<Coro::BDB> for a case where this is useful.
683 855
686If there are any code references in this array (you can C<push> to it 858If there are any code references in this array (you can C<push> to it
687before or after loading AnyEvent), then they will called directly after 859before or after loading AnyEvent), then they will called directly after
688the event loop has been chosen. 860the event loop has been chosen.
689 861
690You should check C<$AnyEvent::MODEL> before adding to this array, though: 862You should check C<$AnyEvent::MODEL> before adding to this array, though:
691if it contains a true value then the event loop has already been detected, 863if it is defined then the event loop has already been detected, and the
692and the array will be ignored. 864array will be ignored.
693 865
694Best use C<AnyEvent::post_detect { BLOCK }> instead. 866Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
867it,as it takes care of these details.
868
869This variable is mainly useful for modules that can do something useful
870when AnyEvent is used and thus want to know when it is initialised, but do
871not need to even load it by default. This array provides the means to hook
872into AnyEvent passively, without loading it.
695 873
696=back 874=back
697 875
698=head1 WHAT TO DO IN A MODULE 876=head1 WHAT TO DO IN A MODULE
699 877
754 932
755 933
756=head1 OTHER MODULES 934=head1 OTHER MODULES
757 935
758The following is a non-exhaustive list of additional modules that use 936The following is a non-exhaustive list of additional modules that use
759AnyEvent and can therefore be mixed easily with other AnyEvent modules 937AnyEvent as a client and can therefore be mixed easily with other AnyEvent
760in the same program. Some of the modules come with AnyEvent, some are 938modules and other event loops in the same program. Some of the modules
761available via CPAN. 939come with AnyEvent, most are available via CPAN.
762 940
763=over 4 941=over 4
764 942
765=item L<AnyEvent::Util> 943=item L<AnyEvent::Util>
766 944
775 953
776=item L<AnyEvent::Handle> 954=item L<AnyEvent::Handle>
777 955
778Provide read and write buffers, manages watchers for reads and writes, 956Provide read and write buffers, manages watchers for reads and writes,
779supports raw and formatted I/O, I/O queued and fully transparent and 957supports raw and formatted I/O, I/O queued and fully transparent and
780non-blocking SSL/TLS. 958non-blocking SSL/TLS (via L<AnyEvent::TLS>.
781 959
782=item L<AnyEvent::DNS> 960=item L<AnyEvent::DNS>
783 961
784Provides rich asynchronous DNS resolver capabilities. 962Provides rich asynchronous DNS resolver capabilities.
785 963
813 991
814=item L<AnyEvent::GPSD> 992=item L<AnyEvent::GPSD>
815 993
816A non-blocking interface to gpsd, a daemon delivering GPS information. 994A non-blocking interface to gpsd, a daemon delivering GPS information.
817 995
996=item L<AnyEvent::IRC>
997
998AnyEvent based IRC client module family (replacing the older Net::IRC3).
999
1000=item L<AnyEvent::XMPP>
1001
1002AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1003Net::XMPP2>.
1004
818=item L<AnyEvent::IGS> 1005=item L<AnyEvent::IGS>
819 1006
820A non-blocking interface to the Internet Go Server protocol (used by 1007A non-blocking interface to the Internet Go Server protocol (used by
821L<App::IGS>). 1008L<App::IGS>).
822 1009
823=item L<Net::IRC3>
824
825AnyEvent based IRC client module family.
826
827=item L<Net::XMPP2>
828
829AnyEvent based XMPP (Jabber protocol) module family.
830
831=item L<Net::FCP> 1010=item L<Net::FCP>
832 1011
833AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1012AnyEvent-based implementation of the Freenet Client Protocol, birthplace
834of AnyEvent. 1013of AnyEvent.
835 1014
839 1018
840=item L<Coro> 1019=item L<Coro>
841 1020
842Has special support for AnyEvent via L<Coro::AnyEvent>. 1021Has special support for AnyEvent via L<Coro::AnyEvent>.
843 1022
844=item L<IO::Lambda>
845
846The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
847
848=back 1023=back
849 1024
850=cut 1025=cut
851 1026
852package AnyEvent; 1027package AnyEvent;
853 1028
854no warnings; 1029no warnings;
855use strict qw(vars subs); 1030use strict qw(vars subs);
856 1031
857use Carp; 1032use Carp ();
858 1033
859our $VERSION = 4.233; 1034our $VERSION = 4.83;
860our $MODEL; 1035our $MODEL;
861 1036
862our $AUTOLOAD; 1037our $AUTOLOAD;
863our @ISA; 1038our @ISA;
864 1039
865our @REGISTRY; 1040our @REGISTRY;
866 1041
867our $WIN32; 1042our $WIN32;
868 1043
869BEGIN { 1044BEGIN {
870 my $win32 = ! ! ($^O =~ /mswin32/i); 1045 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
871 eval "sub WIN32(){ $win32 }"; 1046 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
1047
1048 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1049 if ${^TAINT};
872} 1050}
873 1051
874our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1052our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
875 1053
876our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1054our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
887 [Event:: => AnyEvent::Impl::Event::], 1065 [Event:: => AnyEvent::Impl::Event::],
888 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1066 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
889 # everything below here will not be autoprobed 1067 # everything below here will not be autoprobed
890 # as the pureperl backend should work everywhere 1068 # as the pureperl backend should work everywhere
891 # and is usually faster 1069 # and is usually faster
892 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
893 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1070 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
894 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1071 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1072 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
895 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1073 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
896 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1074 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897 [Wx:: => AnyEvent::Impl::POE::], 1075 [Wx:: => AnyEvent::Impl::POE::],
898 [Prima:: => AnyEvent::Impl::POE::], 1076 [Prima:: => AnyEvent::Impl::POE::],
1077 # IO::Async is just too broken - we would need workarounds for its
1078 # byzantine signal and broken child handling, among others.
1079 # IO::Async is rather hard to detect, as it doesn't have any
1080 # obvious default class.
1081# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1082# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1083# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
899); 1084);
900 1085
901our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 1086our %method = map +($_ => 1),
1087 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
902 1088
903our @post_detect; 1089our @post_detect;
904 1090
905sub post_detect(&) { 1091sub post_detect(&) {
906 my ($cb) = @_; 1092 my ($cb) = @_;
911 1 1097 1
912 } else { 1098 } else {
913 push @post_detect, $cb; 1099 push @post_detect, $cb;
914 1100
915 defined wantarray 1101 defined wantarray
916 ? bless \$cb, "AnyEvent::Util::PostDetect" 1102 ? bless \$cb, "AnyEvent::Util::postdetect"
917 : () 1103 : ()
918 } 1104 }
919} 1105}
920 1106
921sub AnyEvent::Util::PostDetect::DESTROY { 1107sub AnyEvent::Util::postdetect::DESTROY {
922 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1108 @post_detect = grep $_ != ${$_[0]}, @post_detect;
923} 1109}
924 1110
925sub detect() { 1111sub detect() {
926 unless ($MODEL) { 1112 unless ($MODEL) {
929 1115
930 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1116 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
931 my $model = "AnyEvent::Impl::$1"; 1117 my $model = "AnyEvent::Impl::$1";
932 if (eval "require $model") { 1118 if (eval "require $model") {
933 $MODEL = $model; 1119 $MODEL = $model;
934 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1120 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1;
935 } else { 1121 } else {
936 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1122 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose;
937 } 1123 }
938 } 1124 }
939 1125
940 # check for already loaded models 1126 # check for already loaded models
941 unless ($MODEL) { 1127 unless ($MODEL) {
963 last; 1149 last;
964 } 1150 }
965 } 1151 }
966 1152
967 $MODEL 1153 $MODEL
968 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1154 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
969 } 1155 }
970 } 1156 }
971 1157
972 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1158 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973 1159
983 1169
984sub AUTOLOAD { 1170sub AUTOLOAD {
985 (my $func = $AUTOLOAD) =~ s/.*://; 1171 (my $func = $AUTOLOAD) =~ s/.*://;
986 1172
987 $method{$func} 1173 $method{$func}
988 or croak "$func: not a valid method for AnyEvent objects"; 1174 or Carp::croak "$func: not a valid method for AnyEvent objects";
989 1175
990 detect unless $MODEL; 1176 detect unless $MODEL;
991 1177
992 my $class = shift; 1178 my $class = shift;
993 $class->$func (@_); 1179 $class->$func (@_);
994} 1180}
995 1181
996# utility function to dup a filehandle. this is used by many backends 1182# utility function to dup a filehandle. this is used by many backends
997# to support binding more than one watcher per filehandle (they usually 1183# to support binding more than one watcher per filehandle (they usually
998# allow only one watcher per fd, so we dup it to get a different one). 1184# allow only one watcher per fd, so we dup it to get a different one).
999sub _dupfh($$$$) { 1185sub _dupfh($$;$$) {
1000 my ($poll, $fh, $r, $w) = @_; 1186 my ($poll, $fh, $r, $w) = @_;
1001 1187
1002 require Fcntl;
1003
1004 # cygwin requires the fh mode to be matching, unix doesn't 1188 # cygwin requires the fh mode to be matching, unix doesn't
1005 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1189 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1006 : $poll eq "w" ? ($w, ">")
1007 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1008 1190
1009 open my $fh2, "$mode&" . fileno $fh 1191 open my $fh2, $mode, $fh
1010 or die "cannot dup() filehandle: $!"; 1192 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1011 1193
1012 # we assume CLOEXEC is already set by perl in all important cases 1194 # we assume CLOEXEC is already set by perl in all important cases
1013 1195
1014 ($fh2, $rw) 1196 ($fh2, $rw)
1015} 1197}
1016 1198
1017package AnyEvent::Base; 1199package AnyEvent::Base;
1018 1200
1019# default implementation for now and time 1201# default implementations for many methods
1020 1202
1021BEGIN { 1203BEGIN {
1022 if (eval "use Time::HiRes (); time (); 1") { 1204 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1023 *_time = \&Time::HiRes::time; 1205 *_time = \&Time::HiRes::time;
1024 # if (eval "use POSIX (); (POSIX::times())... 1206 # if (eval "use POSIX (); (POSIX::times())...
1025 } else { 1207 } else {
1026 *_time = \&CORE::time; # epic fail 1208 *_time = sub { time }; # epic fail
1027 } 1209 }
1028} 1210}
1029 1211
1030sub time { _time } 1212sub time { _time }
1031sub now { _time } 1213sub now { _time }
1214sub now_update { }
1032 1215
1033# default implementation for ->condvar 1216# default implementation for ->condvar
1034 1217
1035sub condvar { 1218sub condvar {
1036 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1219 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1037} 1220}
1038 1221
1039# default implementation for ->signal 1222# default implementation for ->signal
1040 1223
1041our %SIG_CB; 1224our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1225
1226sub _signal_exec {
1227 sysread $SIGPIPE_R, my $dummy, 4;
1228
1229 while (%SIG_EV) {
1230 for (keys %SIG_EV) {
1231 delete $SIG_EV{$_};
1232 $_->() for values %{ $SIG_CB{$_} || {} };
1233 }
1234 }
1235}
1042 1236
1043sub signal { 1237sub signal {
1044 my (undef, %arg) = @_; 1238 my (undef, %arg) = @_;
1045 1239
1240 unless ($SIGPIPE_R) {
1241 require Fcntl;
1242
1243 if (AnyEvent::WIN32) {
1244 require AnyEvent::Util;
1245
1246 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1247 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1248 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1249 } else {
1250 pipe $SIGPIPE_R, $SIGPIPE_W;
1251 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1252 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1253
1254 # not strictly required, as $^F is normally 2, but let's make sure...
1255 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1256 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1257 }
1258
1259 $SIGPIPE_R
1260 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1261
1262 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1263 }
1264
1046 my $signal = uc $arg{signal} 1265 my $signal = uc $arg{signal}
1047 or Carp::croak "required option 'signal' is missing"; 1266 or Carp::croak "required option 'signal' is missing";
1048 1267
1049 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1268 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1050 $SIG{$signal} ||= sub { 1269 $SIG{$signal} ||= sub {
1051 $_->() for values %{ $SIG_CB{$signal} || {} }; 1270 local $!;
1271 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1272 undef $SIG_EV{$signal};
1052 }; 1273 };
1053 1274
1054 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1275 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1055} 1276}
1056 1277
1057sub AnyEvent::Base::Signal::DESTROY { 1278sub AnyEvent::Base::signal::DESTROY {
1058 my ($signal, $cb) = @{$_[0]}; 1279 my ($signal, $cb) = @{$_[0]};
1059 1280
1060 delete $SIG_CB{$signal}{$cb}; 1281 delete $SIG_CB{$signal}{$cb};
1061 1282
1283 # delete doesn't work with older perls - they then
1284 # print weird messages, or just unconditionally exit
1285 # instead of getting the default action.
1062 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1286 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1063} 1287}
1064 1288
1065# default implementation for ->child 1289# default implementation for ->child
1066 1290
1067our %PID_CB; 1291our %PID_CB;
1068our $CHLD_W; 1292our $CHLD_W;
1069our $CHLD_DELAY_W; 1293our $CHLD_DELAY_W;
1070our $PID_IDLE;
1071our $WNOHANG; 1294our $WNOHANG;
1072 1295
1073sub _child_wait { 1296sub _sigchld {
1074 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1297 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1075 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1298 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1076 (values %{ $PID_CB{0} || {} }); 1299 (values %{ $PID_CB{0} || {} });
1077 } 1300 }
1078
1079 undef $PID_IDLE;
1080}
1081
1082sub _sigchld {
1083 # make sure we deliver these changes "synchronous" with the event loop.
1084 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1085 undef $CHLD_DELAY_W;
1086 &_child_wait;
1087 });
1088} 1301}
1089 1302
1090sub child { 1303sub child {
1091 my (undef, %arg) = @_; 1304 my (undef, %arg) = @_;
1092 1305
1093 defined (my $pid = $arg{pid} + 0) 1306 defined (my $pid = $arg{pid} + 0)
1094 or Carp::croak "required option 'pid' is missing"; 1307 or Carp::croak "required option 'pid' is missing";
1095 1308
1096 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1309 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1097 1310
1098 unless ($WNOHANG) {
1099 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1311 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1100 }
1101 1312
1102 unless ($CHLD_W) { 1313 unless ($CHLD_W) {
1103 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1314 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1104 # child could be a zombie already, so make at least one round 1315 # child could be a zombie already, so make at least one round
1105 &_sigchld; 1316 &_sigchld;
1106 } 1317 }
1107 1318
1108 bless [$pid, $arg{cb}], "AnyEvent::Base::Child" 1319 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1109} 1320}
1110 1321
1111sub AnyEvent::Base::Child::DESTROY { 1322sub AnyEvent::Base::child::DESTROY {
1112 my ($pid, $cb) = @{$_[0]}; 1323 my ($pid, $cb) = @{$_[0]};
1113 1324
1114 delete $PID_CB{$pid}{$cb}; 1325 delete $PID_CB{$pid}{$cb};
1115 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1326 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1116 1327
1117 undef $CHLD_W unless keys %PID_CB; 1328 undef $CHLD_W unless keys %PID_CB;
1329}
1330
1331# idle emulation is done by simply using a timer, regardless
1332# of whether the process is idle or not, and not letting
1333# the callback use more than 50% of the time.
1334sub idle {
1335 my (undef, %arg) = @_;
1336
1337 my ($cb, $w, $rcb) = $arg{cb};
1338
1339 $rcb = sub {
1340 if ($cb) {
1341 $w = _time;
1342 &$cb;
1343 $w = _time - $w;
1344
1345 # never use more then 50% of the time for the idle watcher,
1346 # within some limits
1347 $w = 0.0001 if $w < 0.0001;
1348 $w = 5 if $w > 5;
1349
1350 $w = AnyEvent->timer (after => $w, cb => $rcb);
1351 } else {
1352 # clean up...
1353 undef $w;
1354 undef $rcb;
1355 }
1356 };
1357
1358 $w = AnyEvent->timer (after => 0.05, cb => $rcb);
1359
1360 bless \\$cb, "AnyEvent::Base::idle"
1361}
1362
1363sub AnyEvent::Base::idle::DESTROY {
1364 undef $${$_[0]};
1118} 1365}
1119 1366
1120package AnyEvent::CondVar; 1367package AnyEvent::CondVar;
1121 1368
1122our @ISA = AnyEvent::CondVar::Base::; 1369our @ISA = AnyEvent::CondVar::Base::;
1124package AnyEvent::CondVar::Base; 1371package AnyEvent::CondVar::Base;
1125 1372
1126use overload 1373use overload
1127 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1374 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1128 fallback => 1; 1375 fallback => 1;
1376
1377our $WAITING;
1129 1378
1130sub _send { 1379sub _send {
1131 # nop 1380 # nop
1132} 1381}
1133 1382
1146sub ready { 1395sub ready {
1147 $_[0]{_ae_sent} 1396 $_[0]{_ae_sent}
1148} 1397}
1149 1398
1150sub _wait { 1399sub _wait {
1400 $WAITING
1401 and !$_[0]{_ae_sent}
1402 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1403
1404 local $WAITING = 1;
1151 AnyEvent->one_event while !$_[0]{_ae_sent}; 1405 AnyEvent->one_event while !$_[0]{_ae_sent};
1152} 1406}
1153 1407
1154sub recv { 1408sub recv {
1155 $_[0]->_wait; 1409 $_[0]->_wait;
1196so on. 1450so on.
1197 1451
1198=head1 ENVIRONMENT VARIABLES 1452=head1 ENVIRONMENT VARIABLES
1199 1453
1200The following environment variables are used by this module or its 1454The following environment variables are used by this module or its
1201submodules: 1455submodules.
1456
1457Note that AnyEvent will remove I<all> environment variables starting with
1458C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
1459enabled.
1202 1460
1203=over 4 1461=over 4
1204 1462
1205=item C<PERL_ANYEVENT_VERBOSE> 1463=item C<PERL_ANYEVENT_VERBOSE>
1206 1464
1218=item C<PERL_ANYEVENT_STRICT> 1476=item C<PERL_ANYEVENT_STRICT>
1219 1477
1220AnyEvent does not do much argument checking by default, as thorough 1478AnyEvent does not do much argument checking by default, as thorough
1221argument checking is very costly. Setting this variable to a true value 1479argument checking is very costly. Setting this variable to a true value
1222will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1480will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1223check the arguments passed to most method calls. If it finds any problems 1481check the arguments passed to most method calls. If it finds any problems,
1224it will croak. 1482it will croak.
1225 1483
1226In other words, enables "strict" mode. 1484In other words, enables "strict" mode.
1227 1485
1228Unlike C<use strict>, it is definitely recommended ot keep it off in 1486Unlike C<use strict>, it is definitely recommended to keep it off in
1229production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1487production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1230developing programs can be very useful, however. 1488developing programs can be very useful, however.
1231 1489
1232=item C<PERL_ANYEVENT_MODEL> 1490=item C<PERL_ANYEVENT_MODEL>
1233 1491
1256used, and preference will be given to protocols mentioned earlier in the 1514used, and preference will be given to protocols mentioned earlier in the
1257list. 1515list.
1258 1516
1259This variable can effectively be used for denial-of-service attacks 1517This variable can effectively be used for denial-of-service attacks
1260against local programs (e.g. when setuid), although the impact is likely 1518against local programs (e.g. when setuid), although the impact is likely
1261small, as the program has to handle connection errors already- 1519small, as the program has to handle conenction and other failures anyways.
1262 1520
1263Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, 1521Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1264but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 1522but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1265- only support IPv4, never try to resolve or contact IPv6 1523- only support IPv4, never try to resolve or contact IPv6
1266addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 1524addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1278 1536
1279=item C<PERL_ANYEVENT_MAX_FORKS> 1537=item C<PERL_ANYEVENT_MAX_FORKS>
1280 1538
1281The maximum number of child processes that C<AnyEvent::Util::fork_call> 1539The maximum number of child processes that C<AnyEvent::Util::fork_call>
1282will create in parallel. 1540will create in parallel.
1541
1542=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1543
1544The default value for the C<max_outstanding> parameter for the default DNS
1545resolver - this is the maximum number of parallel DNS requests that are
1546sent to the DNS server.
1547
1548=item C<PERL_ANYEVENT_RESOLV_CONF>
1549
1550The file to use instead of F</etc/resolv.conf> (or OS-specific
1551configuration) in the default resolver. When set to the empty string, no
1552default config will be used.
1553
1554=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1555
1556When neither C<ca_file> nor C<ca_path> was specified during
1557L<AnyEvent::TLS> context creation, and either of these environment
1558variables exist, they will be used to specify CA certificate locations
1559instead of a system-dependent default.
1283 1560
1284=back 1561=back
1285 1562
1286=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1563=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1287 1564
1526watcher. 1803watcher.
1527 1804
1528=head3 Results 1805=head3 Results
1529 1806
1530 name watchers bytes create invoke destroy comment 1807 name watchers bytes create invoke destroy comment
1531 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 1808 EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1532 EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers 1809 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1533 CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal 1810 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1534 Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation 1811 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1535 Event/Event 16000 516 31.88 31.30 0.85 Event native interface 1812 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1536 Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers 1813 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1814 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
1815 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1537 Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour 1816 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1538 Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers 1817 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1539 POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event 1818 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1540 POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select 1819 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1541 1820
1542=head3 Discussion 1821=head3 Discussion
1543 1822
1544The benchmark does I<not> measure scalability of the event loop very 1823The benchmark does I<not> measure scalability of the event loop very
1545well. For example, a select-based event loop (such as the pure perl one) 1824well. For example, a select-based event loop (such as the pure perl one)
1570performance becomes really bad with lots of file descriptors (and few of 1849performance becomes really bad with lots of file descriptors (and few of
1571them active), of course, but this was not subject of this benchmark. 1850them active), of course, but this was not subject of this benchmark.
1572 1851
1573The C<Event> module has a relatively high setup and callback invocation 1852The C<Event> module has a relatively high setup and callback invocation
1574cost, but overall scores in on the third place. 1853cost, but overall scores in on the third place.
1854
1855C<IO::Async> performs admirably well, about on par with C<Event>, even
1856when using its pure perl backend.
1575 1857
1576C<Glib>'s memory usage is quite a bit higher, but it features a 1858C<Glib>'s memory usage is quite a bit higher, but it features a
1577faster callback invocation and overall ends up in the same class as 1859faster callback invocation and overall ends up in the same class as
1578C<Event>. However, Glib scales extremely badly, doubling the number of 1860C<Event>. However, Glib scales extremely badly, doubling the number of
1579watchers increases the processing time by more than a factor of four, 1861watchers increases the processing time by more than a factor of four,
1657it to another server. This includes deleting the old timeout and creating 1939it to another server. This includes deleting the old timeout and creating
1658a new one that moves the timeout into the future. 1940a new one that moves the timeout into the future.
1659 1941
1660=head3 Results 1942=head3 Results
1661 1943
1662 name sockets create request 1944 name sockets create request
1663 EV 20000 69.01 11.16 1945 EV 20000 69.01 11.16
1664 Perl 20000 73.32 35.87 1946 Perl 20000 73.32 35.87
1947 IOAsync 20000 157.00 98.14 epoll
1948 IOAsync 20000 159.31 616.06 poll
1665 Event 20000 212.62 257.32 1949 Event 20000 212.62 257.32
1666 Glib 20000 651.16 1896.30 1950 Glib 20000 651.16 1896.30
1667 POE 20000 349.67 12317.24 uses POE::Loop::Event 1951 POE 20000 349.67 12317.24 uses POE::Loop::Event
1668 1952
1669=head3 Discussion 1953=head3 Discussion
1670 1954
1671This benchmark I<does> measure scalability and overall performance of the 1955This benchmark I<does> measure scalability and overall performance of the
1672particular event loop. 1956particular event loop.
1674EV is again fastest. Since it is using epoll on my system, the setup time 1958EV is again fastest. Since it is using epoll on my system, the setup time
1675is relatively high, though. 1959is relatively high, though.
1676 1960
1677Perl surprisingly comes second. It is much faster than the C-based event 1961Perl surprisingly comes second. It is much faster than the C-based event
1678loops Event and Glib. 1962loops Event and Glib.
1963
1964IO::Async performs very well when using its epoll backend, and still quite
1965good compared to Glib when using its pure perl backend.
1679 1966
1680Event suffers from high setup time as well (look at its code and you will 1967Event suffers from high setup time as well (look at its code and you will
1681understand why). Callback invocation also has a high overhead compared to 1968understand why). Callback invocation also has a high overhead compared to
1682the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 1969the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1683uses select or poll in basically all documented configurations. 1970uses select or poll in basically all documented configurations.
1746=item * C-based event loops perform very well with small number of 2033=item * C-based event loops perform very well with small number of
1747watchers, as the management overhead dominates. 2034watchers, as the management overhead dominates.
1748 2035
1749=back 2036=back
1750 2037
2038=head2 THE IO::Lambda BENCHMARK
2039
2040Recently I was told about the benchmark in the IO::Lambda manpage, which
2041could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
2042simply compares IO::Lambda with POE, and IO::Lambda looks better (which
2043shouldn't come as a surprise to anybody). As such, the benchmark is
2044fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
2045very optimal. But how would AnyEvent compare when used without the extra
2046baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
2047
2048The benchmark itself creates an echo-server, and then, for 500 times,
2049connects to the echo server, sends a line, waits for the reply, and then
2050creates the next connection. This is a rather bad benchmark, as it doesn't
2051test the efficiency of the framework or much non-blocking I/O, but it is a
2052benchmark nevertheless.
2053
2054 name runtime
2055 Lambda/select 0.330 sec
2056 + optimized 0.122 sec
2057 Lambda/AnyEvent 0.327 sec
2058 + optimized 0.138 sec
2059 Raw sockets/select 0.077 sec
2060 POE/select, components 0.662 sec
2061 POE/select, raw sockets 0.226 sec
2062 POE/select, optimized 0.404 sec
2063
2064 AnyEvent/select/nb 0.085 sec
2065 AnyEvent/EV/nb 0.068 sec
2066 +state machine 0.134 sec
2067
2068The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
2069benchmarks actually make blocking connects and use 100% blocking I/O,
2070defeating the purpose of an event-based solution. All of the newly
2071written AnyEvent benchmarks use 100% non-blocking connects (using
2072AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
2073resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
2074generally require a lot more bookkeeping and event handling than blocking
2075connects (which involve a single syscall only).
2076
2077The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
2078offers similar expressive power as POE and IO::Lambda, using conventional
2079Perl syntax. This means that both the echo server and the client are 100%
2080non-blocking, further placing it at a disadvantage.
2081
2082As you can see, the AnyEvent + EV combination even beats the
2083hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2084backend easily beats IO::Lambda and POE.
2085
2086And even the 100% non-blocking version written using the high-level (and
2087slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
2088large margin, even though it does all of DNS, tcp-connect and socket I/O
2089in a non-blocking way.
2090
2091The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2092F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2093part of the IO::lambda distribution and were used without any changes.
2094
2095
2096=head1 SIGNALS
2097
2098AnyEvent currently installs handlers for these signals:
2099
2100=over 4
2101
2102=item SIGCHLD
2103
2104A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2105emulation for event loops that do not support them natively. Also, some
2106event loops install a similar handler.
2107
2108Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2109AnyEvent will reset it to default, to avoid losing child exit statuses.
2110
2111=item SIGPIPE
2112
2113A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2114when AnyEvent gets loaded.
2115
2116The rationale for this is that AnyEvent users usually do not really depend
2117on SIGPIPE delivery (which is purely an optimisation for shell use, or
2118badly-written programs), but C<SIGPIPE> can cause spurious and rare
2119program exits as a lot of people do not expect C<SIGPIPE> when writing to
2120some random socket.
2121
2122The rationale for installing a no-op handler as opposed to ignoring it is
2123that this way, the handler will be restored to defaults on exec.
2124
2125Feel free to install your own handler, or reset it to defaults.
2126
2127=back
2128
2129=cut
2130
2131undef $SIG{CHLD}
2132 if $SIG{CHLD} eq 'IGNORE';
2133
2134$SIG{PIPE} = sub { }
2135 unless defined $SIG{PIPE};
1751 2136
1752=head1 FORK 2137=head1 FORK
1753 2138
1754Most event libraries are not fork-safe. The ones who are usually are 2139Most event libraries are not fork-safe. The ones who are usually are
1755because they rely on inefficient but fork-safe C<select> or C<poll> 2140because they rely on inefficient but fork-safe C<select> or C<poll>
1776 use AnyEvent; 2161 use AnyEvent;
1777 2162
1778Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2163Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1779be used to probe what backend is used and gain other information (which is 2164be used to probe what backend is used and gain other information (which is
1780probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2165probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1781$ENV{PERL_ANYEGENT_STRICT}. 2166$ENV{PERL_ANYEVENT_STRICT}.
2167
2168Note that AnyEvent will remove I<all> environment variables starting with
2169C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2170enabled.
1782 2171
1783 2172
1784=head1 BUGS 2173=head1 BUGS
1785 2174
1786Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2175Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1787to work around. If you suffer from memleaks, first upgrade to Perl 5.10 2176to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1788and check wether the leaks still show up. (Perl 5.10.0 has other annoying 2177and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1789mamleaks, such as leaking on C<map> and C<grep> but it is usually not as 2178memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1790pronounced). 2179pronounced).
1791 2180
1792 2181
1793=head1 SEE ALSO 2182=head1 SEE ALSO
1794 2183
1798L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2187L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1799 2188
1800Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2189Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1801L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2190L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1802L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2191L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1803L<AnyEvent::Impl::POE>. 2192L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1804 2193
1805Non-blocking file handles, sockets, TCP clients and 2194Non-blocking file handles, sockets, TCP clients and
1806servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2195servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1807 2196
1808Asynchronous DNS: L<AnyEvent::DNS>. 2197Asynchronous DNS: L<AnyEvent::DNS>.
1809 2198
1810Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2199Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2200L<Coro::Event>,
1811 2201
1812Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2202Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2203L<AnyEvent::HTTP>.
1813 2204
1814 2205
1815=head1 AUTHOR 2206=head1 AUTHOR
1816 2207
1817 Marc Lehmann <schmorp@schmorp.de> 2208 Marc Lehmann <schmorp@schmorp.de>

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