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1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - events independent of event loop implementation
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
6event loops. 6event loops.
7 7
8=head1 SYNOPSIS 8=head1 SYNOPSIS
40=head1 INTRODUCTION/TUTORIAL 40=head1 INTRODUCTION/TUTORIAL
41 41
42This manpage is mainly a reference manual. If you are interested 42This manpage is mainly a reference manual. If you are interested
43in a tutorial or some gentle introduction, have a look at the 43in a tutorial or some gentle introduction, have a look at the
44L<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
52Respository>, at L<http://anyevent.schmorp.de>, for more info.
45 53
46=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47 55
48Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49nowadays. So what is different about AnyEvent? 57nowadays. So what is different about AnyEvent?
176=head2 I/O WATCHERS 184=head2 I/O WATCHERS
177 185
178You can create an I/O watcher by calling the C<< AnyEvent->io >> method 186You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179with the following mandatory key-value pairs as arguments: 187with the following mandatory key-value pairs as arguments:
180 188
181C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch 189C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182for events (AnyEvent might or might not keep a reference to this file 190for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which 191handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets, 192non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files 193most character devices, pipes, fifos and so on, but not for example files
186or block devices. 194or block devices.
361invocation, and callback invocation will be synchronous. Synchronous means 369invocation, and callback invocation will be synchronous. Synchronous means
362that it might take a while until the signal gets handled by the process, 370that it might take a while until the signal gets handled by the process,
363but it is guaranteed not to interrupt any other callbacks. 371but it is guaranteed not to interrupt any other callbacks.
364 372
365The main advantage of using these watchers is that you can share a signal 373The main advantage of using these watchers is that you can share a signal
366between multiple watchers. 374between multiple watchers, and AnyEvent will ensure that signals will not
375interrupt your program at bad times.
367 376
368This watcher might use C<%SIG>, so programs overwriting those signals 377This watcher might use C<%SIG> (depending on the event loop used),
369directly will likely not work correctly. 378so programs overwriting those signals directly will likely not work
379correctly.
370 380
371Example: exit on SIGINT 381Example: exit on SIGINT
372 382
373 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 383 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384
385=head3 Signal Races, Delays and Workarounds
386
387Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
388callbacks to signals in a generic way, which is a pity, as you cannot do
389race-free signal handling in perl. AnyEvent will try to do it's best, but
390in some cases, signals will be delayed. The maximum time a signal might
391be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
392seconds). This variable can be changed only before the first signal
393watcher is created, and should be left alone otherwise. Higher values
394will cause fewer spurious wake-ups, which is better for power and CPU
395saving. All these problems can be avoided by installing the optional
396L<Async::Interrupt> module. This will not work with inherently broken
397event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
398currently, as POE does it's own workaround with one-second latency). With
399those, you just have to suffer the delays.
374 400
375=head2 CHILD PROCESS WATCHERS 401=head2 CHILD PROCESS WATCHERS
376 402
377You can also watch on a child process exit and catch its exit status. 403You can also watch on a child process exit and catch its exit status.
378 404
392 418
393There is a slight catch to child watchers, however: you usually start them 419There is a slight catch to child watchers, however: you usually start them
394I<after> the child process was created, and this means the process could 420I<after> the child process was created, and this means the process could
395have exited already (and no SIGCHLD will be sent anymore). 421have exited already (and no SIGCHLD will be sent anymore).
396 422
397Not all event models handle this correctly (POE doesn't), but even for 423Not all event models handle this correctly (neither POE nor IO::Async do,
424see their AnyEvent::Impl manpages for details), but even for event models
398event models that I<do> handle this correctly, they usually need to be 425that I<do> handle this correctly, they usually need to be loaded before
399loaded before the process exits (i.e. before you fork in the first place). 426the process exits (i.e. before you fork in the first place). AnyEvent's
427pure perl event loop handles all cases correctly regardless of when you
428start the watcher.
400 429
401This means you cannot create a child watcher as the very first thing in an 430This means you cannot create a child watcher as the very first
402AnyEvent program, you I<have> to create at least one watcher before you 431thing in an AnyEvent program, you I<have> to create at least one
403C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 432watcher before you C<fork> the child (alternatively, you can call
433C<AnyEvent::detect>).
434
435As most event loops do not support waiting for child events, they will be
436emulated by AnyEvent in most cases, in which the latency and race problems
437mentioned in the description of signal watchers apply.
404 438
405Example: fork a process and wait for it 439Example: fork a process and wait for it
406 440
407 my $done = AnyEvent->condvar; 441 my $done = AnyEvent->condvar;
408 442
459 493
460If you are familiar with some event loops you will know that all of them 494If you are familiar with some event loops you will know that all of them
461require you to run some blocking "loop", "run" or similar function that 495require you to run some blocking "loop", "run" or similar function that
462will actively watch for new events and call your callbacks. 496will actively watch for new events and call your callbacks.
463 497
464AnyEvent is different, it expects somebody else to run the event loop and 498AnyEvent is slightly different: it expects somebody else to run the event
465will only block when necessary (usually when told by the user). 499loop and will only block when necessary (usually when told by the user).
466 500
467The instrument to do that is called a "condition variable", so called 501The instrument to do that is called a "condition variable", so called
468because they represent a condition that must become true. 502because they represent a condition that must become true.
469 503
504Now is probably a good time to look at the examples further below.
505
470Condition variables can be created by calling the C<< AnyEvent->condvar 506Condition variables can be created by calling the C<< AnyEvent->condvar
471>> method, usually without arguments. The only argument pair allowed is 507>> method, usually without arguments. The only argument pair allowed is
472
473C<cb>, which specifies a callback to be called when the condition variable 508C<cb>, which specifies a callback to be called when the condition variable
474becomes true, with the condition variable as the first argument (but not 509becomes true, with the condition variable as the first argument (but not
475the results). 510the results).
476 511
477After creation, the condition variable is "false" until it becomes "true" 512After creation, the condition variable is "false" until it becomes "true"
482Condition variables are similar to callbacks, except that you can 517Condition variables are similar to callbacks, except that you can
483optionally wait for them. They can also be called merge points - points 518optionally wait for them. They can also be called merge points - points
484in time where multiple outstanding events have been processed. And yet 519in time where multiple outstanding events have been processed. And yet
485another way to call them is transactions - each condition variable can be 520another way to call them is transactions - each condition variable can be
486used to represent a transaction, which finishes at some point and delivers 521used to represent a transaction, which finishes at some point and delivers
487a result. 522a result. And yet some people know them as "futures" - a promise to
523compute/deliver something that you can wait for.
488 524
489Condition variables are very useful to signal that something has finished, 525Condition variables are very useful to signal that something has finished,
490for example, if you write a module that does asynchronous http requests, 526for example, if you write a module that does asynchronous http requests,
491then a condition variable would be the ideal candidate to signal the 527then a condition variable would be the ideal candidate to signal the
492availability of results. The user can either act when the callback is 528availability of results. The user can either act when the callback is
526 after => 1, 562 after => 1,
527 cb => sub { $result_ready->send }, 563 cb => sub { $result_ready->send },
528 ); 564 );
529 565
530 # this "blocks" (while handling events) till the callback 566 # this "blocks" (while handling events) till the callback
531 # calls send 567 # calls -<send
532 $result_ready->recv; 568 $result_ready->recv;
533 569
534Example: wait for a timer, but take advantage of the fact that 570Example: wait for a timer, but take advantage of the fact that condition
535condition variables are also code references. 571variables are also callable directly.
536 572
537 my $done = AnyEvent->condvar; 573 my $done = AnyEvent->condvar;
538 my $delay = AnyEvent->timer (after => 5, cb => $done); 574 my $delay = AnyEvent->timer (after => 5, cb => $done);
539 $done->recv; 575 $done->recv;
540 576
546 582
547 ... 583 ...
548 584
549 my @info = $couchdb->info->recv; 585 my @info = $couchdb->info->recv;
550 586
551And this is how you would just ste a callback to be called whenever the 587And this is how you would just set a callback to be called whenever the
552results are available: 588results are available:
553 589
554 $couchdb->info->cb (sub { 590 $couchdb->info->cb (sub {
555 my @info = $_[0]->recv; 591 my @info = $_[0]->recv;
556 }); 592 });
574immediately from within send. 610immediately from within send.
575 611
576Any arguments passed to the C<send> call will be returned by all 612Any arguments passed to the C<send> call will be returned by all
577future C<< ->recv >> calls. 613future C<< ->recv >> calls.
578 614
579Condition variables are overloaded so one can call them directly 615Condition variables are overloaded so one can call them directly (as if
580(as a code reference). Calling them directly is the same as calling 616they were a code reference). Calling them directly is the same as calling
581C<send>. Note, however, that many C-based event loops do not handle 617C<send>.
582overloading, so as tempting as it may be, passing a condition variable
583instead of a callback does not work. Both the pure perl and EV loops
584support overloading, however, as well as all functions that use perl to
585invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
586example).
587 618
588=item $cv->croak ($error) 619=item $cv->croak ($error)
589 620
590Similar to send, but causes all call's to C<< ->recv >> to invoke 621Similar to send, but causes all call's to C<< ->recv >> to invoke
591C<Carp::croak> with the given error message/object/scalar. 622C<Carp::croak> with the given error message/object/scalar.
592 623
593This can be used to signal any errors to the condition variable 624This can be used to signal any errors to the condition variable
594user/consumer. 625user/consumer. Doing it this way instead of calling C<croak> directly
626delays the error detetcion, but has the overwhelmign advantage that it
627diagnoses the error at the place where the result is expected, and not
628deep in some event clalback without connection to the actual code causing
629the problem.
595 630
596=item $cv->begin ([group callback]) 631=item $cv->begin ([group callback])
597 632
598=item $cv->end 633=item $cv->end
599
600These two methods are EXPERIMENTAL and MIGHT CHANGE.
601 634
602These two methods can be used to combine many transactions/events into 635These two methods can be used to combine many transactions/events into
603one. For example, a function that pings many hosts in parallel might want 636one. For example, a function that pings many hosts in parallel might want
604to use a condition variable for the whole process. 637to use a condition variable for the whole process.
605 638
607C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 640C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
608>>, the (last) callback passed to C<begin> will be executed. That callback 641>>, the (last) callback passed to C<begin> will be executed. That callback
609is I<supposed> to call C<< ->send >>, but that is not required. If no 642is I<supposed> to call C<< ->send >>, but that is not required. If no
610callback was set, C<send> will be called without any arguments. 643callback was set, C<send> will be called without any arguments.
611 644
612Let's clarify this with the ping example: 645You can think of C<< $cv->send >> giving you an OR condition (one call
646sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
647condition (all C<begin> calls must be C<end>'ed before the condvar sends).
648
649Let's start with a simple example: you have two I/O watchers (for example,
650STDOUT and STDERR for a program), and you want to wait for both streams to
651close before activating a condvar:
652
653 my $cv = AnyEvent->condvar;
654
655 $cv->begin; # first watcher
656 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
657 defined sysread $fh1, my $buf, 4096
658 or $cv->end;
659 });
660
661 $cv->begin; # second watcher
662 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
663 defined sysread $fh2, my $buf, 4096
664 or $cv->end;
665 });
666
667 $cv->recv;
668
669This works because for every event source (EOF on file handle), there is
670one call to C<begin>, so the condvar waits for all calls to C<end> before
671sending.
672
673The ping example mentioned above is slightly more complicated, as the
674there are results to be passwd back, and the number of tasks that are
675begung can potentially be zero:
613 676
614 my $cv = AnyEvent->condvar; 677 my $cv = AnyEvent->condvar;
615 678
616 my %result; 679 my %result;
617 $cv->begin (sub { $cv->send (\%result) }); 680 $cv->begin (sub { $cv->send (\%result) });
637loop, which serves two important purposes: first, it sets the callback 700loop, which serves two important purposes: first, it sets the callback
638to be called once the counter reaches C<0>, and second, it ensures that 701to be called once the counter reaches C<0>, and second, it ensures that
639C<send> is called even when C<no> hosts are being pinged (the loop 702C<send> is called even when C<no> hosts are being pinged (the loop
640doesn't execute once). 703doesn't execute once).
641 704
642This is the general pattern when you "fan out" into multiple subrequests: 705This is the general pattern when you "fan out" into multiple (but
643use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 706potentially none) subrequests: use an outer C<begin>/C<end> pair to set
644is called at least once, and then, for each subrequest you start, call 707the callback and ensure C<end> is called at least once, and then, for each
645C<begin> and for each subrequest you finish, call C<end>. 708subrequest you start, call C<begin> and for each subrequest you finish,
709call C<end>.
646 710
647=back 711=back
648 712
649=head3 METHODS FOR CONSUMERS 713=head3 METHODS FOR CONSUMERS
650 714
666function will call C<croak>. 730function will call C<croak>.
667 731
668In list context, all parameters passed to C<send> will be returned, 732In list context, all parameters passed to C<send> will be returned,
669in scalar context only the first one will be returned. 733in scalar context only the first one will be returned.
670 734
735Note that doing a blocking wait in a callback is not supported by any
736event loop, that is, recursive invocation of a blocking C<< ->recv
737>> is not allowed, and the C<recv> call will C<croak> if such a
738condition is detected. This condition can be slightly loosened by using
739L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
740any thread that doesn't run the event loop itself.
741
671Not all event models support a blocking wait - some die in that case 742Not all event models support a blocking wait - some die in that case
672(programs might want to do that to stay interactive), so I<if you are 743(programs might want to do that to stay interactive), so I<if you are
673using this from a module, never require a blocking wait>, but let the 744using this from a module, never require a blocking wait>. Instead, let the
674caller decide whether the call will block or not (for example, by coupling 745caller decide whether the call will block or not (for example, by coupling
675condition variables with some kind of request results and supporting 746condition variables with some kind of request results and supporting
676callbacks so the caller knows that getting the result will not block, 747callbacks so the caller knows that getting the result will not block,
677while still supporting blocking waits if the caller so desires). 748while still supporting blocking waits if the caller so desires).
678 749
679Another reason I<never> to C<< ->recv >> in a module is that you cannot
680sensibly have two C<< ->recv >>'s in parallel, as that would require
681multiple interpreters or coroutines/threads, none of which C<AnyEvent>
682can supply.
683
684The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
685fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
686versions and also integrates coroutines into AnyEvent, making blocking
687C<< ->recv >> calls perfectly safe as long as they are done from another
688coroutine (one that doesn't run the event loop).
689
690You can ensure that C<< -recv >> never blocks by setting a callback and 750You can ensure that C<< -recv >> never blocks by setting a callback and
691only calling C<< ->recv >> from within that callback (or at a later 751only calling C<< ->recv >> from within that callback (or at a later
692time). This will work even when the event loop does not support blocking 752time). This will work even when the event loop does not support blocking
693waits otherwise. 753waits otherwise.
694 754
707variable itself. Calling C<recv> inside the callback or at any later time 767variable itself. Calling C<recv> inside the callback or at any later time
708is guaranteed not to block. 768is guaranteed not to block.
709 769
710=back 770=back
711 771
772=head1 SUPPORTED EVENT LOOPS/BACKENDS
773
774The available backend classes are (every class has its own manpage):
775
776=over 4
777
778=item Backends that are autoprobed when no other event loop can be found.
779
780EV is the preferred backend when no other event loop seems to be in
781use. If EV is not installed, then AnyEvent will try Event, and, failing
782that, will fall back to its own pure-perl implementation, which is
783available everywhere as it comes with AnyEvent itself.
784
785 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
786 AnyEvent::Impl::Event based on Event, very stable, few glitches.
787 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
788
789=item Backends that are transparently being picked up when they are used.
790
791These will be used when they are currently loaded when the first watcher
792is created, in which case it is assumed that the application is using
793them. This means that AnyEvent will automatically pick the right backend
794when the main program loads an event module before anything starts to
795create watchers. Nothing special needs to be done by the main program.
796
797 AnyEvent::Impl::Glib based on Glib, slow but very stable.
798 AnyEvent::Impl::Tk based on Tk, very broken.
799 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
800 AnyEvent::Impl::POE based on POE, very slow, some limitations.
801
802=item Backends with special needs.
803
804Qt requires the Qt::Application to be instantiated first, but will
805otherwise be picked up automatically. As long as the main program
806instantiates the application before any AnyEvent watchers are created,
807everything should just work.
808
809 AnyEvent::Impl::Qt based on Qt.
810
811Support for IO::Async can only be partial, as it is too broken and
812architecturally limited to even support the AnyEvent API. It also
813is the only event loop that needs the loop to be set explicitly, so
814it can only be used by a main program knowing about AnyEvent. See
815L<AnyEvent::Impl::Async> for the gory details.
816
817 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
818
819=item Event loops that are indirectly supported via other backends.
820
821Some event loops can be supported via other modules:
822
823There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
824
825B<WxWidgets> has no support for watching file handles. However, you can
826use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
827polls 20 times per second, which was considered to be too horrible to even
828consider for AnyEvent.
829
830B<Prima> is not supported as nobody seems to be using it, but it has a POE
831backend, so it can be supported through POE.
832
833AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
834load L<POE> when detecting them, in the hope that POE will pick them up,
835in which case everything will be automatic.
836
837=back
838
712=head1 GLOBAL VARIABLES AND FUNCTIONS 839=head1 GLOBAL VARIABLES AND FUNCTIONS
713 840
841These are not normally required to use AnyEvent, but can be useful to
842write AnyEvent extension modules.
843
714=over 4 844=over 4
715 845
716=item $AnyEvent::MODEL 846=item $AnyEvent::MODEL
717 847
718Contains C<undef> until the first watcher is being created. Then it 848Contains C<undef> until the first watcher is being created, before the
849backend has been autodetected.
850
719contains the event model that is being used, which is the name of the 851Afterwards it contains the event model that is being used, which is the
720Perl class implementing the model. This class is usually one of the 852name of the Perl class implementing the model. This class is usually one
721C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 853of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 854case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723 855will be C<urxvt::anyevent>).
724The known classes so far are:
725
726 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727 AnyEvent::Impl::Event based on Event, second best choice.
728 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729 AnyEvent::Impl::Glib based on Glib, third-best choice.
730 AnyEvent::Impl::Tk based on Tk, very bad choice.
731 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733 AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735There is no support for WxWidgets, as WxWidgets has no support for
736watching file handles. However, you can use WxWidgets through the
737POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738second, which was considered to be too horrible to even consider for
739AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740it's adaptor.
741
742AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743autodetecting them.
744 856
745=item AnyEvent::detect 857=item AnyEvent::detect
746 858
747Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 859Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748if necessary. You should only call this function right before you would 860if necessary. You should only call this function right before you would
749have created an AnyEvent watcher anyway, that is, as late as possible at 861have created an AnyEvent watcher anyway, that is, as late as possible at
750runtime. 862runtime, and not e.g. while initialising of your module.
863
864If you need to do some initialisation before AnyEvent watchers are
865created, use C<post_detect>.
751 866
752=item $guard = AnyEvent::post_detect { BLOCK } 867=item $guard = AnyEvent::post_detect { BLOCK }
753 868
754Arranges for the code block to be executed as soon as the event model is 869Arranges for the code block to be executed as soon as the event model is
755autodetected (or immediately if this has already happened). 870autodetected (or immediately if this has already happened).
871
872The block will be executed I<after> the actual backend has been detected
873(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
874created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
875other initialisations - see the sources of L<AnyEvent::Strict> or
876L<AnyEvent::AIO> to see how this is used.
877
878The most common usage is to create some global watchers, without forcing
879event module detection too early, for example, L<AnyEvent::AIO> creates
880and installs the global L<IO::AIO> watcher in a C<post_detect> block to
881avoid autodetecting the event module at load time.
756 882
757If called in scalar or list context, then it creates and returns an object 883If called in scalar or list context, then it creates and returns an object
758that automatically removes the callback again when it is destroyed. See 884that automatically removes the callback again when it is destroyed. See
759L<Coro::BDB> for a case where this is useful. 885L<Coro::BDB> for a case where this is useful.
760 886
763If there are any code references in this array (you can C<push> to it 889If there are any code references in this array (you can C<push> to it
764before or after loading AnyEvent), then they will called directly after 890before or after loading AnyEvent), then they will called directly after
765the event loop has been chosen. 891the event loop has been chosen.
766 892
767You should check C<$AnyEvent::MODEL> before adding to this array, though: 893You should check C<$AnyEvent::MODEL> before adding to this array, though:
768if it contains a true value then the event loop has already been detected, 894if it is defined then the event loop has already been detected, and the
769and the array will be ignored. 895array will be ignored.
770 896
771Best use C<AnyEvent::post_detect { BLOCK }> instead. 897Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
898it,as it takes care of these details.
899
900This variable is mainly useful for modules that can do something useful
901when AnyEvent is used and thus want to know when it is initialised, but do
902not need to even load it by default. This array provides the means to hook
903into AnyEvent passively, without loading it.
772 904
773=back 905=back
774 906
775=head1 WHAT TO DO IN A MODULE 907=head1 WHAT TO DO IN A MODULE
776 908
831 963
832 964
833=head1 OTHER MODULES 965=head1 OTHER MODULES
834 966
835The following is a non-exhaustive list of additional modules that use 967The following is a non-exhaustive list of additional modules that use
836AnyEvent and can therefore be mixed easily with other AnyEvent modules 968AnyEvent as a client and can therefore be mixed easily with other AnyEvent
837in the same program. Some of the modules come with AnyEvent, some are 969modules and other event loops in the same program. Some of the modules
838available via CPAN. 970come with AnyEvent, most are available via CPAN.
839 971
840=over 4 972=over 4
841 973
842=item L<AnyEvent::Util> 974=item L<AnyEvent::Util>
843 975
852 984
853=item L<AnyEvent::Handle> 985=item L<AnyEvent::Handle>
854 986
855Provide read and write buffers, manages watchers for reads and writes, 987Provide read and write buffers, manages watchers for reads and writes,
856supports raw and formatted I/O, I/O queued and fully transparent and 988supports raw and formatted I/O, I/O queued and fully transparent and
857non-blocking SSL/TLS. 989non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858 990
859=item L<AnyEvent::DNS> 991=item L<AnyEvent::DNS>
860 992
861Provides rich asynchronous DNS resolver capabilities. 993Provides rich asynchronous DNS resolver capabilities.
862 994
890 1022
891=item L<AnyEvent::GPSD> 1023=item L<AnyEvent::GPSD>
892 1024
893A non-blocking interface to gpsd, a daemon delivering GPS information. 1025A non-blocking interface to gpsd, a daemon delivering GPS information.
894 1026
1027=item L<AnyEvent::IRC>
1028
1029AnyEvent based IRC client module family (replacing the older Net::IRC3).
1030
1031=item L<AnyEvent::XMPP>
1032
1033AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1034Net::XMPP2>.
1035
895=item L<AnyEvent::IGS> 1036=item L<AnyEvent::IGS>
896 1037
897A non-blocking interface to the Internet Go Server protocol (used by 1038A non-blocking interface to the Internet Go Server protocol (used by
898L<App::IGS>). 1039L<App::IGS>).
899 1040
900=item L<AnyEvent::IRC>
901
902AnyEvent based IRC client module family (replacing the older Net::IRC3).
903
904=item L<Net::XMPP2>
905
906AnyEvent based XMPP (Jabber protocol) module family.
907
908=item L<Net::FCP> 1041=item L<Net::FCP>
909 1042
910AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1043AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911of AnyEvent. 1044of AnyEvent.
912 1045
916 1049
917=item L<Coro> 1050=item L<Coro>
918 1051
919Has special support for AnyEvent via L<Coro::AnyEvent>. 1052Has special support for AnyEvent via L<Coro::AnyEvent>.
920 1053
921=item L<IO::Lambda>
922
923The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925=back 1054=back
926 1055
927=cut 1056=cut
928 1057
929package AnyEvent; 1058package AnyEvent;
930 1059
1060# basically a tuned-down version of common::sense
1061sub common_sense {
931no warnings; 1062 # no warnings
1063 ${^WARNING_BITS} ^= ${^WARNING_BITS};
932use strict qw(vars subs); 1064 # use strict vars subs
1065 $^H |= 0x00000600;
1066}
933 1067
1068BEGIN { AnyEvent::common_sense }
1069
934use Carp; 1070use Carp ();
935 1071
936our $VERSION = 4.411; 1072our $VERSION = 4.85;
937our $MODEL; 1073our $MODEL;
938 1074
939our $AUTOLOAD; 1075our $AUTOLOAD;
940our @ISA; 1076our @ISA;
941 1077
942our @REGISTRY; 1078our @REGISTRY;
943 1079
944our $WIN32; 1080our $WIN32;
1081
1082our $VERBOSE;
945 1083
946BEGIN { 1084BEGIN {
947 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1085 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1086 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949 1087
950 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1088 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951 if ${^TAINT}; 1089 if ${^TAINT};
952}
953 1090
954our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1091 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1092
1093}
1094
1095our $MAX_SIGNAL_LATENCY = 10;
955 1096
956our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1097our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
957 1098
958{ 1099{
959 my $idx; 1100 my $idx;
967 [Event:: => AnyEvent::Impl::Event::], 1108 [Event:: => AnyEvent::Impl::Event::],
968 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1109 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
969 # everything below here will not be autoprobed 1110 # everything below here will not be autoprobed
970 # as the pureperl backend should work everywhere 1111 # as the pureperl backend should work everywhere
971 # and is usually faster 1112 # and is usually faster
972 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
973 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1113 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
974 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1114 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1115 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
975 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1116 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1117 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977 [Wx:: => AnyEvent::Impl::POE::], 1118 [Wx:: => AnyEvent::Impl::POE::],
978 [Prima:: => AnyEvent::Impl::POE::], 1119 [Prima:: => AnyEvent::Impl::POE::],
1120 # IO::Async is just too broken - we would need workarounds for its
1121 # byzantine signal and broken child handling, among others.
1122 # IO::Async is rather hard to detect, as it doesn't have any
1123 # obvious default class.
1124# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1125# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1126# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
979); 1127);
980 1128
981our %method = map +($_ => 1), 1129our %method = map +($_ => 1),
982 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1130 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983 1131
1003 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1151 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1004} 1152}
1005 1153
1006sub detect() { 1154sub detect() {
1007 unless ($MODEL) { 1155 unless ($MODEL) {
1008 no strict 'refs';
1009 local $SIG{__DIE__}; 1156 local $SIG{__DIE__};
1010 1157
1011 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1158 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012 my $model = "AnyEvent::Impl::$1"; 1159 my $model = "AnyEvent::Impl::$1";
1013 if (eval "require $model") { 1160 if (eval "require $model") {
1014 $MODEL = $model; 1161 $MODEL = $model;
1015 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1162 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1016 } else { 1163 } else {
1017 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1164 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1018 } 1165 }
1019 } 1166 }
1020 1167
1021 # check for already loaded models 1168 # check for already loaded models
1022 unless ($MODEL) { 1169 unless ($MODEL) {
1023 for (@REGISTRY, @models) { 1170 for (@REGISTRY, @models) {
1024 my ($package, $model) = @$_; 1171 my ($package, $model) = @$_;
1025 if (${"$package\::VERSION"} > 0) { 1172 if (${"$package\::VERSION"} > 0) {
1026 if (eval "require $model") { 1173 if (eval "require $model") {
1027 $MODEL = $model; 1174 $MODEL = $model;
1028 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1175 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1029 last; 1176 last;
1030 } 1177 }
1031 } 1178 }
1032 } 1179 }
1033 1180
1038 my ($package, $model) = @$_; 1185 my ($package, $model) = @$_;
1039 if (eval "require $package" 1186 if (eval "require $package"
1040 and ${"$package\::VERSION"} > 0 1187 and ${"$package\::VERSION"} > 0
1041 and eval "require $model") { 1188 and eval "require $model") {
1042 $MODEL = $model; 1189 $MODEL = $model;
1043 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1190 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1044 last; 1191 last;
1045 } 1192 }
1046 } 1193 }
1047 1194
1048 $MODEL 1195 $MODEL
1064 1211
1065sub AUTOLOAD { 1212sub AUTOLOAD {
1066 (my $func = $AUTOLOAD) =~ s/.*://; 1213 (my $func = $AUTOLOAD) =~ s/.*://;
1067 1214
1068 $method{$func} 1215 $method{$func}
1069 or croak "$func: not a valid method for AnyEvent objects"; 1216 or Carp::croak "$func: not a valid method for AnyEvent objects";
1070 1217
1071 detect unless $MODEL; 1218 detect unless $MODEL;
1072 1219
1073 my $class = shift; 1220 my $class = shift;
1074 $class->$func (@_); 1221 $class->$func (@_);
1075} 1222}
1076 1223
1077# utility function to dup a filehandle. this is used by many backends 1224# utility function to dup a filehandle. this is used by many backends
1078# to support binding more than one watcher per filehandle (they usually 1225# to support binding more than one watcher per filehandle (they usually
1079# allow only one watcher per fd, so we dup it to get a different one). 1226# allow only one watcher per fd, so we dup it to get a different one).
1080sub _dupfh($$$$) { 1227sub _dupfh($$;$$) {
1081 my ($poll, $fh, $r, $w) = @_; 1228 my ($poll, $fh, $r, $w) = @_;
1082 1229
1083 # cygwin requires the fh mode to be matching, unix doesn't 1230 # cygwin requires the fh mode to be matching, unix doesn't
1084 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1231 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1085 : $poll eq "w" ? ($w, ">")
1086 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087 1232
1088 open my $fh2, "$mode&" . fileno $fh 1233 open my $fh2, $mode, $fh
1089 or die "cannot dup() filehandle: $!,"; 1234 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090 1235
1091 # we assume CLOEXEC is already set by perl in all important cases 1236 # we assume CLOEXEC is already set by perl in all important cases
1092 1237
1093 ($fh2, $rw) 1238 ($fh2, $rw)
1094} 1239}
1095 1240
1096package AnyEvent::Base; 1241package AnyEvent::Base;
1097 1242
1098# default implementations for many methods 1243# default implementations for many methods
1099 1244
1100BEGIN { 1245sub _time {
1246 # probe for availability of Time::HiRes
1101 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1247 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1248 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102 *_time = \&Time::HiRes::time; 1249 *_time = \&Time::HiRes::time;
1103 # if (eval "use POSIX (); (POSIX::times())... 1250 # if (eval "use POSIX (); (POSIX::times())...
1104 } else { 1251 } else {
1252 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105 *_time = sub { time }; # epic fail 1253 *_time = sub { time }; # epic fail
1106 } 1254 }
1255
1256 &_time
1107} 1257}
1108 1258
1109sub time { _time } 1259sub time { _time }
1110sub now { _time } 1260sub now { _time }
1111sub now_update { } 1261sub now_update { }
1116 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1266 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117} 1267}
1118 1268
1119# default implementation for ->signal 1269# default implementation for ->signal
1120 1270
1271our $HAVE_ASYNC_INTERRUPT;
1121our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1272our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1273our (%SIG_ASY, %SIG_ASY_W);
1274our ($SIG_COUNT, $SIG_TW);
1122 1275
1123sub _signal_exec { 1276sub _signal_exec {
1277 $HAVE_ASYNC_INTERRUPT
1278 ? $SIGPIPE_R->drain
1124 sysread $SIGPIPE_R, my $dummy, 4; 1279 : sysread $SIGPIPE_R, my $dummy, 9;
1125 1280
1126 while (%SIG_EV) { 1281 while (%SIG_EV) {
1127 for (keys %SIG_EV) { 1282 for (keys %SIG_EV) {
1128 delete $SIG_EV{$_}; 1283 delete $SIG_EV{$_};
1129 $_->() for values %{ $SIG_CB{$_} || {} }; 1284 $_->() for values %{ $SIG_CB{$_} || {} };
1130 } 1285 }
1131 } 1286 }
1132} 1287}
1133 1288
1289# install a dumym wakeupw atcher to reduce signal catching latency
1290sub _sig_add() {
1291 unless ($SIG_COUNT++) {
1292 # try to align timer on a full-second boundary, if possible
1293 my $NOW = AnyEvent->now;
1294
1295 $SIG_TW = AnyEvent->timer (
1296 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1297 interval => $MAX_SIGNAL_LATENCY,
1298 cb => sub { }, # just for the PERL_ASYNC_CHECK
1299 );
1300 }
1301}
1302
1303sub _sig_del {
1304 undef $SIG_TW
1305 unless --$SIG_COUNT;
1306}
1307
1308sub _signal {
1309 my (undef, %arg) = @_;
1310
1311 my $signal = uc $arg{signal}
1312 or Carp::croak "required option 'signal' is missing";
1313
1314 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1315
1316 if ($HAVE_ASYNC_INTERRUPT) {
1317 # async::interrupt
1318
1319 $SIG_ASY{$signal} ||= do {
1320 my $asy = new Async::Interrupt
1321 cb => sub { undef $SIG_EV{$signal} },
1322 signal => $signal,
1323 pipe => [$SIGPIPE_R->filenos],
1324 ;
1325 $asy->pipe_autodrain (0);
1326
1327 $asy
1328 };
1329
1330 } else {
1331 # pure perl
1332
1333 $SIG{$signal} ||= sub {
1334 local $!;
1335 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1336 undef $SIG_EV{$signal};
1337 };
1338
1339 # can't do signal processing without introducing races in pure perl,
1340 # so limit the signal latency.
1341 _sig_add;
1342 }
1343
1344 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1345}
1346
1134sub signal { 1347sub signal {
1135 my (undef, %arg) = @_; 1348 # probe for availability of Async::Interrupt
1349 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1350 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136 1351
1137 unless ($SIGPIPE_R) { 1352 $HAVE_ASYNC_INTERRUPT = 1;
1353 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1354 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1355
1356 } else {
1357 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1358
1138 require Fcntl; 1359 require Fcntl;
1139 1360
1140 if (AnyEvent::WIN32) { 1361 if (AnyEvent::WIN32) {
1141 require AnyEvent::Util; 1362 require AnyEvent::Util;
1142 1363
1157 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1378 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1158 1379
1159 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); 1380 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1160 } 1381 }
1161 1382
1162 my $signal = uc $arg{signal} 1383 *signal = \&_signal;
1163 or Carp::croak "required option 'signal' is missing"; 1384 &signal
1164
1165 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1166 $SIG{$signal} ||= sub {
1167 local $!;
1168 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169 undef $SIG_EV{$signal};
1170 };
1171
1172 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1173} 1385}
1174 1386
1175sub AnyEvent::Base::signal::DESTROY { 1387sub AnyEvent::Base::signal::DESTROY {
1176 my ($signal, $cb) = @{$_[0]}; 1388 my ($signal, $cb) = @{$_[0]};
1177 1389
1390 _sig_del;
1391
1178 delete $SIG_CB{$signal}{$cb}; 1392 delete $SIG_CB{$signal}{$cb};
1179 1393
1394 $HAVE_ASYNC_INTERRUPT
1395 ? delete $SIG_ASY{$signal}
1180 # delete doesn't work with older perls - they then 1396 : # delete doesn't work with older perls - they then
1181 # print weird messages, or just unconditionally exit 1397 # print weird messages, or just unconditionally exit
1182 # instead of getting the default action. 1398 # instead of getting the default action.
1399 undef $SIG{$signal}
1183 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1400 unless keys %{ $SIG_CB{$signal} };
1184} 1401}
1185 1402
1186# default implementation for ->child 1403# default implementation for ->child
1187 1404
1188our %PID_CB; 1405our %PID_CB;
1190our $CHLD_DELAY_W; 1407our $CHLD_DELAY_W;
1191our $WNOHANG; 1408our $WNOHANG;
1192 1409
1193sub _sigchld { 1410sub _sigchld {
1194 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1411 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1412 $_->($pid, $?)
1195 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1413 for values %{ $PID_CB{$pid} || {} },
1196 (values %{ $PID_CB{0} || {} }); 1414 values %{ $PID_CB{0} || {} };
1197 } 1415 }
1198} 1416}
1199 1417
1200sub child { 1418sub child {
1201 my (undef, %arg) = @_; 1419 my (undef, %arg) = @_;
1203 defined (my $pid = $arg{pid} + 0) 1421 defined (my $pid = $arg{pid} + 0)
1204 or Carp::croak "required option 'pid' is missing"; 1422 or Carp::croak "required option 'pid' is missing";
1205 1423
1206 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1424 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207 1425
1426 # WNOHANG is almost cetrainly 1 everywhere
1427 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1428 ? 1
1208 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1429 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1209 1430
1210 unless ($CHLD_W) { 1431 unless ($CHLD_W) {
1211 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1432 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1212 # child could be a zombie already, so make at least one round 1433 # child could be a zombie already, so make at least one round
1213 &_sigchld; 1434 &_sigchld;
1265 1486
1266our @ISA = AnyEvent::CondVar::Base::; 1487our @ISA = AnyEvent::CondVar::Base::;
1267 1488
1268package AnyEvent::CondVar::Base; 1489package AnyEvent::CondVar::Base;
1269 1490
1270use overload 1491#use overload
1271 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1492# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272 fallback => 1; 1493# fallback => 1;
1494
1495# save 300+ kilobytes by dirtily hardcoding overloading
1496${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1497*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1498*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1499${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1500
1501our $WAITING;
1273 1502
1274sub _send { 1503sub _send {
1275 # nop 1504 # nop
1276} 1505}
1277 1506
1290sub ready { 1519sub ready {
1291 $_[0]{_ae_sent} 1520 $_[0]{_ae_sent}
1292} 1521}
1293 1522
1294sub _wait { 1523sub _wait {
1524 $WAITING
1525 and !$_[0]{_ae_sent}
1526 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1527
1528 local $WAITING = 1;
1295 AnyEvent->one_event while !$_[0]{_ae_sent}; 1529 AnyEvent->one_event while !$_[0]{_ae_sent};
1296} 1530}
1297 1531
1298sub recv { 1532sub recv {
1299 $_[0]->_wait; 1533 $_[0]->_wait;
1361C<PERL_ANYEVENT_MODEL>. 1595C<PERL_ANYEVENT_MODEL>.
1362 1596
1363When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1597When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364model it chooses. 1598model it chooses.
1365 1599
1600When set to C<8> or higher, then AnyEvent will report extra information on
1601which optional modules it loads and how it implements certain features.
1602
1366=item C<PERL_ANYEVENT_STRICT> 1603=item C<PERL_ANYEVENT_STRICT>
1367 1604
1368AnyEvent does not do much argument checking by default, as thorough 1605AnyEvent does not do much argument checking by default, as thorough
1369argument checking is very costly. Setting this variable to a true value 1606argument checking is very costly. Setting this variable to a true value
1370will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1607will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371check the arguments passed to most method calls. If it finds any problems 1608check the arguments passed to most method calls. If it finds any problems,
1372it will croak. 1609it will croak.
1373 1610
1374In other words, enables "strict" mode. 1611In other words, enables "strict" mode.
1375 1612
1376Unlike C<use strict>, it is definitely recommended ot keep it off in 1613Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1377production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1614>>, it is definitely recommended to keep it off in production. Keeping
1378developing programs can be very useful, however. 1615C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1616can be very useful, however.
1379 1617
1380=item C<PERL_ANYEVENT_MODEL> 1618=item C<PERL_ANYEVENT_MODEL>
1381 1619
1382This can be used to specify the event model to be used by AnyEvent, before 1620This can be used to specify the event model to be used by AnyEvent, before
1383auto detection and -probing kicks in. It must be a string consisting 1621auto detection and -probing kicks in. It must be a string consisting
1426 1664
1427=item C<PERL_ANYEVENT_MAX_FORKS> 1665=item C<PERL_ANYEVENT_MAX_FORKS>
1428 1666
1429The maximum number of child processes that C<AnyEvent::Util::fork_call> 1667The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430will create in parallel. 1668will create in parallel.
1669
1670=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1671
1672The default value for the C<max_outstanding> parameter for the default DNS
1673resolver - this is the maximum number of parallel DNS requests that are
1674sent to the DNS server.
1675
1676=item C<PERL_ANYEVENT_RESOLV_CONF>
1677
1678The file to use instead of F</etc/resolv.conf> (or OS-specific
1679configuration) in the default resolver. When set to the empty string, no
1680default config will be used.
1681
1682=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1683
1684When neither C<ca_file> nor C<ca_path> was specified during
1685L<AnyEvent::TLS> context creation, and either of these environment
1686variables exist, they will be used to specify CA certificate locations
1687instead of a system-dependent default.
1688
1689=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1690
1691When these are set to C<1>, then the respective modules are not
1692loaded. Mostly good for testing AnyEvent itself.
1431 1693
1432=back 1694=back
1433 1695
1434=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1696=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435 1697
1680 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 1942 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1681 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 1943 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1682 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 1944 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1683 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 1945 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1684 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 1946 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1947 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
1948 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1685 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 1949 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1686 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 1950 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1687 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 1951 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1688 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 1952 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1689 1953
1718performance becomes really bad with lots of file descriptors (and few of 1982performance becomes really bad with lots of file descriptors (and few of
1719them active), of course, but this was not subject of this benchmark. 1983them active), of course, but this was not subject of this benchmark.
1720 1984
1721The C<Event> module has a relatively high setup and callback invocation 1985The C<Event> module has a relatively high setup and callback invocation
1722cost, but overall scores in on the third place. 1986cost, but overall scores in on the third place.
1987
1988C<IO::Async> performs admirably well, about on par with C<Event>, even
1989when using its pure perl backend.
1723 1990
1724C<Glib>'s memory usage is quite a bit higher, but it features a 1991C<Glib>'s memory usage is quite a bit higher, but it features a
1725faster callback invocation and overall ends up in the same class as 1992faster callback invocation and overall ends up in the same class as
1726C<Event>. However, Glib scales extremely badly, doubling the number of 1993C<Event>. However, Glib scales extremely badly, doubling the number of
1727watchers increases the processing time by more than a factor of four, 1994watchers increases the processing time by more than a factor of four,
1805it to another server. This includes deleting the old timeout and creating 2072it to another server. This includes deleting the old timeout and creating
1806a new one that moves the timeout into the future. 2073a new one that moves the timeout into the future.
1807 2074
1808=head3 Results 2075=head3 Results
1809 2076
1810 name sockets create request 2077 name sockets create request
1811 EV 20000 69.01 11.16 2078 EV 20000 69.01 11.16
1812 Perl 20000 73.32 35.87 2079 Perl 20000 73.32 35.87
2080 IOAsync 20000 157.00 98.14 epoll
2081 IOAsync 20000 159.31 616.06 poll
1813 Event 20000 212.62 257.32 2082 Event 20000 212.62 257.32
1814 Glib 20000 651.16 1896.30 2083 Glib 20000 651.16 1896.30
1815 POE 20000 349.67 12317.24 uses POE::Loop::Event 2084 POE 20000 349.67 12317.24 uses POE::Loop::Event
1816 2085
1817=head3 Discussion 2086=head3 Discussion
1818 2087
1819This benchmark I<does> measure scalability and overall performance of the 2088This benchmark I<does> measure scalability and overall performance of the
1820particular event loop. 2089particular event loop.
1822EV is again fastest. Since it is using epoll on my system, the setup time 2091EV is again fastest. Since it is using epoll on my system, the setup time
1823is relatively high, though. 2092is relatively high, though.
1824 2093
1825Perl surprisingly comes second. It is much faster than the C-based event 2094Perl surprisingly comes second. It is much faster than the C-based event
1826loops Event and Glib. 2095loops Event and Glib.
2096
2097IO::Async performs very well when using its epoll backend, and still quite
2098good compared to Glib when using its pure perl backend.
1827 2099
1828Event suffers from high setup time as well (look at its code and you will 2100Event suffers from high setup time as well (look at its code and you will
1829understand why). Callback invocation also has a high overhead compared to 2101understand why). Callback invocation also has a high overhead compared to
1830the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 2102the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831uses select or poll in basically all documented configurations. 2103uses select or poll in basically all documented configurations.
1900 2172
1901Recently I was told about the benchmark in the IO::Lambda manpage, which 2173Recently I was told about the benchmark in the IO::Lambda manpage, which
1902could be misinterpreted to make AnyEvent look bad. In fact, the benchmark 2174could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
1903simply compares IO::Lambda with POE, and IO::Lambda looks better (which 2175simply compares IO::Lambda with POE, and IO::Lambda looks better (which
1904shouldn't come as a surprise to anybody). As such, the benchmark is 2176shouldn't come as a surprise to anybody). As such, the benchmark is
1905fine, and shows that the AnyEvent backend from IO::Lambda isn't very 2177fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
1906optimal. But how would AnyEvent compare when used without the extra 2178very optimal. But how would AnyEvent compare when used without the extra
1907baggage? To explore this, I wrote the equivalent benchmark for AnyEvent. 2179baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
1908 2180
1909The benchmark itself creates an echo-server, and then, for 500 times, 2181The benchmark itself creates an echo-server, and then, for 500 times,
1910connects to the echo server, sends a line, waits for the reply, and then 2182connects to the echo server, sends a line, waits for the reply, and then
1911creates the next connection. This is a rather bad benchmark, as it doesn't 2183creates the next connection. This is a rather bad benchmark, as it doesn't
1912test the efficiency of the framework, but it is a benchmark nevertheless. 2184test the efficiency of the framework or much non-blocking I/O, but it is a
2185benchmark nevertheless.
1913 2186
1914 name runtime 2187 name runtime
1915 Lambda/select 0.330 sec 2188 Lambda/select 0.330 sec
1916 + optimized 0.122 sec 2189 + optimized 0.122 sec
1917 Lambda/AnyEvent 0.327 sec 2190 Lambda/AnyEvent 0.327 sec
1923 2196
1924 AnyEvent/select/nb 0.085 sec 2197 AnyEvent/select/nb 0.085 sec
1925 AnyEvent/EV/nb 0.068 sec 2198 AnyEvent/EV/nb 0.068 sec
1926 +state machine 0.134 sec 2199 +state machine 0.134 sec
1927 2200
1928The benchmark is also a bit unfair (my fault) - the IO::Lambda 2201The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
1929benchmarks actually make blocking connects and use 100% blocking I/O, 2202benchmarks actually make blocking connects and use 100% blocking I/O,
1930defeating the purpose of an event-based solution. All of the newly 2203defeating the purpose of an event-based solution. All of the newly
1931written AnyEvent benchmarks use 100% non-blocking connects (using 2204written AnyEvent benchmarks use 100% non-blocking connects (using
1932AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS 2205AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
1933resolver), so AnyEvent is at a disadvantage here as non-blocking connects 2206resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
1934generally require a lot more bookkeeping and event handling than blocking 2207generally require a lot more bookkeeping and event handling than blocking
1935connects (which involve a single syscall only). 2208connects (which involve a single syscall only).
1936 2209
1937The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which 2210The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
1938offers similar expressive power as POE and IO::Lambda (using conventional 2211offers similar expressive power as POE and IO::Lambda, using conventional
1939Perl syntax), which means both the echo server and the client are 100% 2212Perl syntax. This means that both the echo server and the client are 100%
1940non-blocking w.r.t. I/O, further placing it at a disadvantage. 2213non-blocking, further placing it at a disadvantage.
1941 2214
1942As you can see, AnyEvent + EV even beats the hand-optimised "raw sockets 2215As you can see, the AnyEvent + EV combination even beats the
1943benchmark", while AnyEvent + its pure perl backend easily beats 2216hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1944IO::Lambda and POE. 2217backend easily beats IO::Lambda and POE.
1945 2218
1946And even the 100% non-blocking version written using the high-level (and 2219And even the 100% non-blocking version written using the high-level (and
1947slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda, 2220slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
1948even thought it does all of DNS, tcp-connect and socket I/O in a 2221large margin, even though it does all of DNS, tcp-connect and socket I/O
1949non-blocking way. 2222in a non-blocking way.
2223
2224The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2225F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2226part of the IO::lambda distribution and were used without any changes.
1950 2227
1951 2228
1952=head1 SIGNALS 2229=head1 SIGNALS
1953 2230
1954AnyEvent currently installs handlers for these signals: 2231AnyEvent currently installs handlers for these signals:
1958=item SIGCHLD 2235=item SIGCHLD
1959 2236
1960A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2237A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1961emulation for event loops that do not support them natively. Also, some 2238emulation for event loops that do not support them natively. Also, some
1962event loops install a similar handler. 2239event loops install a similar handler.
2240
2241Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2242AnyEvent will reset it to default, to avoid losing child exit statuses.
1963 2243
1964=item SIGPIPE 2244=item SIGPIPE
1965 2245
1966A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2246A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1967when AnyEvent gets loaded. 2247when AnyEvent gets loaded.
1979 2259
1980=back 2260=back
1981 2261
1982=cut 2262=cut
1983 2263
2264undef $SIG{CHLD}
2265 if $SIG{CHLD} eq 'IGNORE';
2266
1984$SIG{PIPE} = sub { } 2267$SIG{PIPE} = sub { }
1985 unless defined $SIG{PIPE}; 2268 unless defined $SIG{PIPE};
2269
2270=head1 RECOMMENDED/OPTIONAL MODULES
2271
2272One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2273it's built-in modules) are required to use it.
2274
2275That does not mean that AnyEvent won't take advantage of some additional
2276modules if they are installed.
2277
2278This section epxlains which additional modules will be used, and how they
2279affect AnyEvent's operetion.
2280
2281=over 4
2282
2283=item L<Async::Interrupt>
2284
2285This slightly arcane module is used to implement fast signal handling: To
2286my knowledge, there is no way to do completely race-free and quick
2287signal handling in pure perl. To ensure that signals still get
2288delivered, AnyEvent will start an interval timer to wake up perl (and
2289catch the signals) with some delay (default is 10 seconds, look for
2290C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2291
2292If this module is available, then it will be used to implement signal
2293catching, which means that signals will not be delayed, and the event loop
2294will not be interrupted regularly, which is more efficient (And good for
2295battery life on laptops).
2296
2297This affects not just the pure-perl event loop, but also other event loops
2298that have no signal handling on their own (e.g. Glib, Tk, Qt).
2299
2300Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2301and either employ their own workarounds (POE) or use AnyEvent's workaround
2302(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2303does nothing for those backends.
2304
2305=item L<EV>
2306
2307This module isn't really "optional", as it is simply one of the backend
2308event loops that AnyEvent can use. However, it is simply the best event
2309loop available in terms of features, speed and stability: It supports
2310the AnyEvent API optimally, implements all the watcher types in XS, does
2311automatic timer adjustments even when no monotonic clock is available,
2312can take avdantage of advanced kernel interfaces such as C<epoll> and
2313C<kqueue>, and is the fastest backend I<by far>. You can even embed
2314L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2315
2316=item L<Guard>
2317
2318The guard module, when used, will be used to implement
2319C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2320lot less memory), but otherwise doesn't affect guard operation much. It is
2321purely used for performance.
2322
2323=item L<JSON> and L<JSON::XS>
2324
2325This module is required when you want to read or write JSON data via
2326L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2327advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2328
2329In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2330installed.
2331
2332=item L<Net::SSLeay>
2333
2334Implementing TLS/SSL in Perl is certainly interesting, but not very
2335worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2336the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2337
2338=item L<Time::HiRes>
2339
2340This module is part of perl since release 5.008. It will be used when the
2341chosen event library does not come with a timing source on it's own. The
2342pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2343try to use a monotonic clock for timing stability.
2344
2345=back
1986 2346
1987 2347
1988=head1 FORK 2348=head1 FORK
1989 2349
1990Most event libraries are not fork-safe. The ones who are usually are 2350Most event libraries are not fork-safe. The ones who are usually are
1991because they rely on inefficient but fork-safe C<select> or C<poll> 2351because they rely on inefficient but fork-safe C<select> or C<poll>
1992calls. Only L<EV> is fully fork-aware. 2352calls. Only L<EV> is fully fork-aware.
1993 2353
1994If you have to fork, you must either do so I<before> creating your first 2354If you have to fork, you must either do so I<before> creating your first
1995watcher OR you must not use AnyEvent at all in the child. 2355watcher OR you must not use AnyEvent at all in the child OR you must do
2356something completely out of the scope of AnyEvent.
1996 2357
1997 2358
1998=head1 SECURITY CONSIDERATIONS 2359=head1 SECURITY CONSIDERATIONS
1999 2360
2000AnyEvent can be forced to load any event model via 2361AnyEvent can be forced to load any event model via
2014Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2375Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
2015be used to probe what backend is used and gain other information (which is 2376be used to probe what backend is used and gain other information (which is
2016probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2377probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
2017$ENV{PERL_ANYEVENT_STRICT}. 2378$ENV{PERL_ANYEVENT_STRICT}.
2018 2379
2380Note that AnyEvent will remove I<all> environment variables starting with
2381C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2382enabled.
2383
2019 2384
2020=head1 BUGS 2385=head1 BUGS
2021 2386
2022Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2387Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
2023to work around. If you suffer from memleaks, first upgrade to Perl 5.10 2388to work around. If you suffer from memleaks, first upgrade to Perl 5.10
2034L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2399L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2035 2400
2036Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2401Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2037L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2402L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2038L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2403L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2039L<AnyEvent::Impl::POE>. 2404L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
2040 2405
2041Non-blocking file handles, sockets, TCP clients and 2406Non-blocking file handles, sockets, TCP clients and
2042servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2407servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2043 2408
2044Asynchronous DNS: L<AnyEvent::DNS>. 2409Asynchronous DNS: L<AnyEvent::DNS>.
2045 2410
2046Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2411Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2412L<Coro::Event>,
2047 2413
2048Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2414Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2415L<AnyEvent::HTTP>.
2049 2416
2050 2417
2051=head1 AUTHOR 2418=head1 AUTHOR
2052 2419
2053 Marc Lehmann <schmorp@schmorp.de> 2420 Marc Lehmann <schmorp@schmorp.de>

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