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Revision 1.248 by root, Sat Jul 18 22:27:10 2009 UTC

176=head2 I/O WATCHERS 176=head2 I/O WATCHERS
177 177
178You 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
179with the following mandatory key-value pairs as arguments: 179with the following mandatory key-value pairs as arguments:
180 180
181C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch 181C<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 182for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which 183handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets, 184non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files 185most character devices, pipes, fifos and so on, but not for example files
186or block devices. 186or block devices.
361invocation, and callback invocation will be synchronous. Synchronous means 361invocation, and callback invocation will be synchronous. Synchronous means
362that it might take a while until the signal gets handled by the process, 362that it might take a while until the signal gets handled by the process,
363but it is guaranteed not to interrupt any other callbacks. 363but it is guaranteed not to interrupt any other callbacks.
364 364
365The main advantage of using these watchers is that you can share a signal 365The main advantage of using these watchers is that you can share a signal
366between multiple watchers. 366between multiple watchers, and AnyEvent will ensure that signals will not
367interrupt your program at bad times.
367 368
368This watcher might use C<%SIG>, so programs overwriting those signals 369This watcher might use C<%SIG> (depending on the event loop used),
369directly will likely not work correctly. 370so programs overwriting those signals directly will likely not work
371correctly.
370 372
371Example: exit on SIGINT 373Example: exit on SIGINT
372 374
373 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 375 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
376
377=head3 Signal Races, Delays and Workarounds
378
379Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
380callbacks to signals in a generic way, which is a pity, as you cannot do
381race-free signal handling in perl. AnyEvent will try to do it's best, but
382in some cases, signals will be delayed. The maximum time a signal might
383be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
384seconds). This variable can be changed only before the first signal
385watcher is created, and should be left alone otherwise. Higher values
386will cause fewer spurious wake-ups, which is better for power and CPU
387saving. All these problems can be avoided by installing the optional
388L<Async::Interrupt> module. This will not work with inherently broken
389event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
390currently, as POE does it's own workaround with one-second latency). With
391those, you just have to suffer the delays.
374 392
375=head2 CHILD PROCESS WATCHERS 393=head2 CHILD PROCESS WATCHERS
376 394
377You can also watch on a child process exit and catch its exit status. 395You can also watch on a child process exit and catch its exit status.
378 396
392 410
393There is a slight catch to child watchers, however: you usually start them 411There 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 412I<after> the child process was created, and this means the process could
395have exited already (and no SIGCHLD will be sent anymore). 413have exited already (and no SIGCHLD will be sent anymore).
396 414
397Not all event models handle this correctly (POE doesn't), but even for 415Not all event models handle this correctly (neither POE nor IO::Async do,
416see their AnyEvent::Impl manpages for details), but even for event models
398event models that I<do> handle this correctly, they usually need to be 417that 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). 418the process exits (i.e. before you fork in the first place). AnyEvent's
419pure perl event loop handles all cases correctly regardless of when you
420start the watcher.
400 421
401This means you cannot create a child watcher as the very first thing in an 422This means you cannot create a child watcher as the very first
402AnyEvent program, you I<have> to create at least one watcher before you 423thing in an AnyEvent program, you I<have> to create at least one
403C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 424watcher before you C<fork> the child (alternatively, you can call
425C<AnyEvent::detect>).
426
427As most event loops do not support waiting for child events, they will be
428emulated by AnyEvent in most cases, in which the latency and race problems
429mentioned in the description of signal watchers apply.
404 430
405Example: fork a process and wait for it 431Example: fork a process and wait for it
406 432
407 my $done = AnyEvent->condvar; 433 my $done = AnyEvent->condvar;
408 434
459 485
460If you are familiar with some event loops you will know that all of them 486If 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 487require you to run some blocking "loop", "run" or similar function that
462will actively watch for new events and call your callbacks. 488will actively watch for new events and call your callbacks.
463 489
464AnyEvent is different, it expects somebody else to run the event loop and 490AnyEvent is slightly different: it expects somebody else to run the event
465will only block when necessary (usually when told by the user). 491loop and will only block when necessary (usually when told by the user).
466 492
467The instrument to do that is called a "condition variable", so called 493The instrument to do that is called a "condition variable", so called
468because they represent a condition that must become true. 494because they represent a condition that must become true.
469 495
496Now is probably a good time to look at the examples further below.
497
470Condition variables can be created by calling the C<< AnyEvent->condvar 498Condition variables can be created by calling the C<< AnyEvent->condvar
471>> method, usually without arguments. The only argument pair allowed is 499>> method, usually without arguments. The only argument pair allowed is
472
473C<cb>, which specifies a callback to be called when the condition variable 500C<cb>, which specifies a callback to be called when the condition variable
474becomes true, with the condition variable as the first argument (but not 501becomes true, with the condition variable as the first argument (but not
475the results). 502the results).
476 503
477After creation, the condition variable is "false" until it becomes "true" 504After creation, the condition variable is "false" until it becomes "true"
526 after => 1, 553 after => 1,
527 cb => sub { $result_ready->send }, 554 cb => sub { $result_ready->send },
528 ); 555 );
529 556
530 # this "blocks" (while handling events) till the callback 557 # this "blocks" (while handling events) till the callback
531 # calls send 558 # calls -<send
532 $result_ready->recv; 559 $result_ready->recv;
533 560
534Example: wait for a timer, but take advantage of the fact that 561Example: wait for a timer, but take advantage of the fact that condition
535condition variables are also code references. 562variables are also callable directly.
536 563
537 my $done = AnyEvent->condvar; 564 my $done = AnyEvent->condvar;
538 my $delay = AnyEvent->timer (after => 5, cb => $done); 565 my $delay = AnyEvent->timer (after => 5, cb => $done);
539 $done->recv; 566 $done->recv;
540 567
546 573
547 ... 574 ...
548 575
549 my @info = $couchdb->info->recv; 576 my @info = $couchdb->info->recv;
550 577
551And this is how you would just ste a callback to be called whenever the 578And this is how you would just set a callback to be called whenever the
552results are available: 579results are available:
553 580
554 $couchdb->info->cb (sub { 581 $couchdb->info->cb (sub {
555 my @info = $_[0]->recv; 582 my @info = $_[0]->recv;
556 }); 583 });
574immediately from within send. 601immediately from within send.
575 602
576Any arguments passed to the C<send> call will be returned by all 603Any arguments passed to the C<send> call will be returned by all
577future C<< ->recv >> calls. 604future C<< ->recv >> calls.
578 605
579Condition variables are overloaded so one can call them directly 606Condition variables are overloaded so one can call them directly (as if
580(as a code reference). Calling them directly is the same as calling 607they 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 608C<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).
587 609
588=item $cv->croak ($error) 610=item $cv->croak ($error)
589 611
590Similar to send, but causes all call's to C<< ->recv >> to invoke 612Similar to send, but causes all call's to C<< ->recv >> to invoke
591C<Carp::croak> with the given error message/object/scalar. 613C<Carp::croak> with the given error message/object/scalar.
592 614
593This can be used to signal any errors to the condition variable 615This can be used to signal any errors to the condition variable
594user/consumer. 616user/consumer. Doing it this way instead of calling C<croak> directly
617delays the error detetcion, but has the overwhelmign advantage that it
618diagnoses the error at the place where the result is expected, and not
619deep in some event clalback without connection to the actual code causing
620the problem.
595 621
596=item $cv->begin ([group callback]) 622=item $cv->begin ([group callback])
597 623
598=item $cv->end 624=item $cv->end
599
600These two methods are EXPERIMENTAL and MIGHT CHANGE.
601 625
602These two methods can be used to combine many transactions/events into 626These two methods can be used to combine many transactions/events into
603one. For example, a function that pings many hosts in parallel might want 627one. For example, a function that pings many hosts in parallel might want
604to use a condition variable for the whole process. 628to use a condition variable for the whole process.
605 629
607C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 631C<< ->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 632>>, 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 633is I<supposed> to call C<< ->send >>, but that is not required. If no
610callback was set, C<send> will be called without any arguments. 634callback was set, C<send> will be called without any arguments.
611 635
612Let's clarify this with the ping example: 636You can think of C<< $cv->send >> giving you an OR condition (one call
637sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
638condition (all C<begin> calls must be C<end>'ed before the condvar sends).
639
640Let's start with a simple example: you have two I/O watchers (for example,
641STDOUT and STDERR for a program), and you want to wait for both streams to
642close before activating a condvar:
643
644 my $cv = AnyEvent->condvar;
645
646 $cv->begin; # first watcher
647 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
648 defined sysread $fh1, my $buf, 4096
649 or $cv->end;
650 });
651
652 $cv->begin; # second watcher
653 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
654 defined sysread $fh2, my $buf, 4096
655 or $cv->end;
656 });
657
658 $cv->recv;
659
660This works because for every event source (EOF on file handle), there is
661one call to C<begin>, so the condvar waits for all calls to C<end> before
662sending.
663
664The ping example mentioned above is slightly more complicated, as the
665there are results to be passwd back, and the number of tasks that are
666begung can potentially be zero:
613 667
614 my $cv = AnyEvent->condvar; 668 my $cv = AnyEvent->condvar;
615 669
616 my %result; 670 my %result;
617 $cv->begin (sub { $cv->send (\%result) }); 671 $cv->begin (sub { $cv->send (\%result) });
637loop, which serves two important purposes: first, it sets the callback 691loop, which serves two important purposes: first, it sets the callback
638to be called once the counter reaches C<0>, and second, it ensures that 692to 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 693C<send> is called even when C<no> hosts are being pinged (the loop
640doesn't execute once). 694doesn't execute once).
641 695
642This is the general pattern when you "fan out" into multiple subrequests: 696This 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> 697potentially 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 698the 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>. 699subrequest you start, call C<begin> and for each subrequest you finish,
700call C<end>.
646 701
647=back 702=back
648 703
649=head3 METHODS FOR CONSUMERS 704=head3 METHODS FOR CONSUMERS
650 705
666function will call C<croak>. 721function will call C<croak>.
667 722
668In list context, all parameters passed to C<send> will be returned, 723In list context, all parameters passed to C<send> will be returned,
669in scalar context only the first one will be returned. 724in scalar context only the first one will be returned.
670 725
726Note that doing a blocking wait in a callback is not supported by any
727event loop, that is, recursive invocation of a blocking C<< ->recv
728>> is not allowed, and the C<recv> call will C<croak> if such a
729condition is detected. This condition can be slightly loosened by using
730L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
731any thread that doesn't run the event loop itself.
732
671Not all event models support a blocking wait - some die in that case 733Not 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 734(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 735using 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 736caller decide whether the call will block or not (for example, by coupling
675condition variables with some kind of request results and supporting 737condition variables with some kind of request results and supporting
676callbacks so the caller knows that getting the result will not block, 738callbacks so the caller knows that getting the result will not block,
677while still supporting blocking waits if the caller so desires). 739while still supporting blocking waits if the caller so desires).
678 740
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 741You can ensure that C<< -recv >> never blocks by setting a callback and
691only calling C<< ->recv >> from within that callback (or at a later 742only calling C<< ->recv >> from within that callback (or at a later
692time). This will work even when the event loop does not support blocking 743time). This will work even when the event loop does not support blocking
693waits otherwise. 744waits otherwise.
694 745
707variable itself. Calling C<recv> inside the callback or at any later time 758variable itself. Calling C<recv> inside the callback or at any later time
708is guaranteed not to block. 759is guaranteed not to block.
709 760
710=back 761=back
711 762
763=head1 SUPPORTED EVENT LOOPS/BACKENDS
764
765The available backend classes are (every class has its own manpage):
766
767=over 4
768
769=item Backends that are autoprobed when no other event loop can be found.
770
771EV is the preferred backend when no other event loop seems to be in
772use. If EV is not installed, then AnyEvent will try Event, and, failing
773that, will fall back to its own pure-perl implementation, which is
774available everywhere as it comes with AnyEvent itself.
775
776 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
777 AnyEvent::Impl::Event based on Event, very stable, few glitches.
778 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
779
780=item Backends that are transparently being picked up when they are used.
781
782These will be used when they are currently loaded when the first watcher
783is created, in which case it is assumed that the application is using
784them. This means that AnyEvent will automatically pick the right backend
785when the main program loads an event module before anything starts to
786create watchers. Nothing special needs to be done by the main program.
787
788 AnyEvent::Impl::Glib based on Glib, slow but very stable.
789 AnyEvent::Impl::Tk based on Tk, very broken.
790 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
791 AnyEvent::Impl::POE based on POE, very slow, some limitations.
792
793=item Backends with special needs.
794
795Qt requires the Qt::Application to be instantiated first, but will
796otherwise be picked up automatically. As long as the main program
797instantiates the application before any AnyEvent watchers are created,
798everything should just work.
799
800 AnyEvent::Impl::Qt based on Qt.
801
802Support for IO::Async can only be partial, as it is too broken and
803architecturally limited to even support the AnyEvent API. It also
804is the only event loop that needs the loop to be set explicitly, so
805it can only be used by a main program knowing about AnyEvent. See
806L<AnyEvent::Impl::Async> for the gory details.
807
808 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
809
810=item Event loops that are indirectly supported via other backends.
811
812Some event loops can be supported via other modules:
813
814There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
815
816B<WxWidgets> has no support for watching file handles. However, you can
817use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
818polls 20 times per second, which was considered to be too horrible to even
819consider for AnyEvent.
820
821B<Prima> is not supported as nobody seems to be using it, but it has a POE
822backend, so it can be supported through POE.
823
824AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
825load L<POE> when detecting them, in the hope that POE will pick them up,
826in which case everything will be automatic.
827
828=back
829
712=head1 GLOBAL VARIABLES AND FUNCTIONS 830=head1 GLOBAL VARIABLES AND FUNCTIONS
713 831
832These are not normally required to use AnyEvent, but can be useful to
833write AnyEvent extension modules.
834
714=over 4 835=over 4
715 836
716=item $AnyEvent::MODEL 837=item $AnyEvent::MODEL
717 838
718Contains C<undef> until the first watcher is being created. Then it 839Contains C<undef> until the first watcher is being created, before the
840backend has been autodetected.
841
719contains the event model that is being used, which is the name of the 842Afterwards it contains the event model that is being used, which is the
720Perl class implementing the model. This class is usually one of the 843name of the Perl class implementing the model. This class is usually one
721C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 844of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 845case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723 846will be C<urxvt::anyevent>).
724The known classes so far are:
725
726 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727 AnyEvent::Impl::Event based on Event, second best choice.
728 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729 AnyEvent::Impl::Glib based on Glib, third-best choice.
730 AnyEvent::Impl::Tk based on Tk, very bad choice.
731 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733 AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735There is no support for WxWidgets, as WxWidgets has no support for
736watching file handles. However, you can use WxWidgets through the
737POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738second, which was considered to be too horrible to even consider for
739AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740it's adaptor.
741
742AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743autodetecting them.
744 847
745=item AnyEvent::detect 848=item AnyEvent::detect
746 849
747Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 850Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748if necessary. You should only call this function right before you would 851if necessary. You should only call this function right before you would
749have created an AnyEvent watcher anyway, that is, as late as possible at 852have created an AnyEvent watcher anyway, that is, as late as possible at
750runtime. 853runtime, and not e.g. while initialising of your module.
854
855If you need to do some initialisation before AnyEvent watchers are
856created, use C<post_detect>.
751 857
752=item $guard = AnyEvent::post_detect { BLOCK } 858=item $guard = AnyEvent::post_detect { BLOCK }
753 859
754Arranges for the code block to be executed as soon as the event model is 860Arranges for the code block to be executed as soon as the event model is
755autodetected (or immediately if this has already happened). 861autodetected (or immediately if this has already happened).
862
863The block will be executed I<after> the actual backend has been detected
864(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
865created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
866other initialisations - see the sources of L<AnyEvent::Strict> or
867L<AnyEvent::AIO> to see how this is used.
868
869The most common usage is to create some global watchers, without forcing
870event module detection too early, for example, L<AnyEvent::AIO> creates
871and installs the global L<IO::AIO> watcher in a C<post_detect> block to
872avoid autodetecting the event module at load time.
756 873
757If called in scalar or list context, then it creates and returns an object 874If called in scalar or list context, then it creates and returns an object
758that automatically removes the callback again when it is destroyed. See 875that automatically removes the callback again when it is destroyed. See
759L<Coro::BDB> for a case where this is useful. 876L<Coro::BDB> for a case where this is useful.
760 877
763If there are any code references in this array (you can C<push> to it 880If 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 881before or after loading AnyEvent), then they will called directly after
765the event loop has been chosen. 882the event loop has been chosen.
766 883
767You should check C<$AnyEvent::MODEL> before adding to this array, though: 884You should check C<$AnyEvent::MODEL> before adding to this array, though:
768if it contains a true value then the event loop has already been detected, 885if it is defined then the event loop has already been detected, and the
769and the array will be ignored. 886array will be ignored.
770 887
771Best use C<AnyEvent::post_detect { BLOCK }> instead. 888Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
889it,as it takes care of these details.
890
891This variable is mainly useful for modules that can do something useful
892when AnyEvent is used and thus want to know when it is initialised, but do
893not need to even load it by default. This array provides the means to hook
894into AnyEvent passively, without loading it.
772 895
773=back 896=back
774 897
775=head1 WHAT TO DO IN A MODULE 898=head1 WHAT TO DO IN A MODULE
776 899
831 954
832 955
833=head1 OTHER MODULES 956=head1 OTHER MODULES
834 957
835The following is a non-exhaustive list of additional modules that use 958The following is a non-exhaustive list of additional modules that use
836AnyEvent and can therefore be mixed easily with other AnyEvent modules 959AnyEvent 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 960modules and other event loops in the same program. Some of the modules
838available via CPAN. 961come with AnyEvent, most are available via CPAN.
839 962
840=over 4 963=over 4
841 964
842=item L<AnyEvent::Util> 965=item L<AnyEvent::Util>
843 966
852 975
853=item L<AnyEvent::Handle> 976=item L<AnyEvent::Handle>
854 977
855Provide read and write buffers, manages watchers for reads and writes, 978Provide read and write buffers, manages watchers for reads and writes,
856supports raw and formatted I/O, I/O queued and fully transparent and 979supports raw and formatted I/O, I/O queued and fully transparent and
857non-blocking SSL/TLS. 980non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858 981
859=item L<AnyEvent::DNS> 982=item L<AnyEvent::DNS>
860 983
861Provides rich asynchronous DNS resolver capabilities. 984Provides rich asynchronous DNS resolver capabilities.
862 985
890 1013
891=item L<AnyEvent::GPSD> 1014=item L<AnyEvent::GPSD>
892 1015
893A non-blocking interface to gpsd, a daemon delivering GPS information. 1016A non-blocking interface to gpsd, a daemon delivering GPS information.
894 1017
1018=item L<AnyEvent::IRC>
1019
1020AnyEvent based IRC client module family (replacing the older Net::IRC3).
1021
1022=item L<AnyEvent::XMPP>
1023
1024AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1025Net::XMPP2>.
1026
895=item L<AnyEvent::IGS> 1027=item L<AnyEvent::IGS>
896 1028
897A non-blocking interface to the Internet Go Server protocol (used by 1029A non-blocking interface to the Internet Go Server protocol (used by
898L<App::IGS>). 1030L<App::IGS>).
899 1031
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> 1032=item L<Net::FCP>
909 1033
910AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1034AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911of AnyEvent. 1035of AnyEvent.
912 1036
916 1040
917=item L<Coro> 1041=item L<Coro>
918 1042
919Has special support for AnyEvent via L<Coro::AnyEvent>. 1043Has special support for AnyEvent via L<Coro::AnyEvent>.
920 1044
921=item L<IO::Lambda>
922
923The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925=back 1045=back
926 1046
927=cut 1047=cut
928 1048
929package AnyEvent; 1049package AnyEvent;
930 1050
1051# basically a tuned-down version of common::sense
1052sub common_sense {
931no warnings; 1053 # no warnings
1054 ${^WARNING_BITS} ^= ${^WARNING_BITS};
932use strict qw(vars subs); 1055 # use strict vars subs
1056 $^H |= 0x00000600;
1057}
933 1058
1059BEGIN { AnyEvent::common_sense }
1060
934use Carp; 1061use Carp ();
935 1062
936our $VERSION = 4.411; 1063our $VERSION = 4.85;
937our $MODEL; 1064our $MODEL;
938 1065
939our $AUTOLOAD; 1066our $AUTOLOAD;
940our @ISA; 1067our @ISA;
941 1068
942our @REGISTRY; 1069our @REGISTRY;
943 1070
944our $WIN32; 1071our $WIN32;
1072
1073our $VERBOSE;
945 1074
946BEGIN { 1075BEGIN {
947 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1076 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1077 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949 1078
950 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1079 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951 if ${^TAINT}; 1080 if ${^TAINT};
952}
953 1081
954our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1082 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1083
1084}
1085
1086our $MAX_SIGNAL_LATENCY = 10;
955 1087
956our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1088our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
957 1089
958{ 1090{
959 my $idx; 1091 my $idx;
967 [Event:: => AnyEvent::Impl::Event::], 1099 [Event:: => AnyEvent::Impl::Event::],
968 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1100 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
969 # everything below here will not be autoprobed 1101 # everything below here will not be autoprobed
970 # as the pureperl backend should work everywhere 1102 # as the pureperl backend should work everywhere
971 # and is usually faster 1103 # and is usually faster
972 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
973 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1104 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
974 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1105 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1106 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
975 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1107 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1108 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977 [Wx:: => AnyEvent::Impl::POE::], 1109 [Wx:: => AnyEvent::Impl::POE::],
978 [Prima:: => AnyEvent::Impl::POE::], 1110 [Prima:: => AnyEvent::Impl::POE::],
1111 # IO::Async is just too broken - we would need workarounds for its
1112 # byzantine signal and broken child handling, among others.
1113 # IO::Async is rather hard to detect, as it doesn't have any
1114 # obvious default class.
1115# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1116# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1117# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
979); 1118);
980 1119
981our %method = map +($_ => 1), 1120our %method = map +($_ => 1),
982 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1121 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983 1122
1003 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1142 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1004} 1143}
1005 1144
1006sub detect() { 1145sub detect() {
1007 unless ($MODEL) { 1146 unless ($MODEL) {
1008 no strict 'refs';
1009 local $SIG{__DIE__}; 1147 local $SIG{__DIE__};
1010 1148
1011 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1149 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012 my $model = "AnyEvent::Impl::$1"; 1150 my $model = "AnyEvent::Impl::$1";
1013 if (eval "require $model") { 1151 if (eval "require $model") {
1014 $MODEL = $model; 1152 $MODEL = $model;
1015 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1153 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1016 } else { 1154 } else {
1017 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1155 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1018 } 1156 }
1019 } 1157 }
1020 1158
1021 # check for already loaded models 1159 # check for already loaded models
1022 unless ($MODEL) { 1160 unless ($MODEL) {
1023 for (@REGISTRY, @models) { 1161 for (@REGISTRY, @models) {
1024 my ($package, $model) = @$_; 1162 my ($package, $model) = @$_;
1025 if (${"$package\::VERSION"} > 0) { 1163 if (${"$package\::VERSION"} > 0) {
1026 if (eval "require $model") { 1164 if (eval "require $model") {
1027 $MODEL = $model; 1165 $MODEL = $model;
1028 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1166 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1029 last; 1167 last;
1030 } 1168 }
1031 } 1169 }
1032 } 1170 }
1033 1171
1038 my ($package, $model) = @$_; 1176 my ($package, $model) = @$_;
1039 if (eval "require $package" 1177 if (eval "require $package"
1040 and ${"$package\::VERSION"} > 0 1178 and ${"$package\::VERSION"} > 0
1041 and eval "require $model") { 1179 and eval "require $model") {
1042 $MODEL = $model; 1180 $MODEL = $model;
1043 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1181 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1044 last; 1182 last;
1045 } 1183 }
1046 } 1184 }
1047 1185
1048 $MODEL 1186 $MODEL
1064 1202
1065sub AUTOLOAD { 1203sub AUTOLOAD {
1066 (my $func = $AUTOLOAD) =~ s/.*://; 1204 (my $func = $AUTOLOAD) =~ s/.*://;
1067 1205
1068 $method{$func} 1206 $method{$func}
1069 or croak "$func: not a valid method for AnyEvent objects"; 1207 or Carp::croak "$func: not a valid method for AnyEvent objects";
1070 1208
1071 detect unless $MODEL; 1209 detect unless $MODEL;
1072 1210
1073 my $class = shift; 1211 my $class = shift;
1074 $class->$func (@_); 1212 $class->$func (@_);
1075} 1213}
1076 1214
1077# utility function to dup a filehandle. this is used by many backends 1215# utility function to dup a filehandle. this is used by many backends
1078# to support binding more than one watcher per filehandle (they usually 1216# 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). 1217# allow only one watcher per fd, so we dup it to get a different one).
1080sub _dupfh($$$$) { 1218sub _dupfh($$;$$) {
1081 my ($poll, $fh, $r, $w) = @_; 1219 my ($poll, $fh, $r, $w) = @_;
1082 1220
1083 # cygwin requires the fh mode to be matching, unix doesn't 1221 # cygwin requires the fh mode to be matching, unix doesn't
1084 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1222 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 1223
1088 open my $fh2, "$mode&" . fileno $fh 1224 open my $fh2, $mode, $fh
1089 or die "cannot dup() filehandle: $!,"; 1225 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090 1226
1091 # we assume CLOEXEC is already set by perl in all important cases 1227 # we assume CLOEXEC is already set by perl in all important cases
1092 1228
1093 ($fh2, $rw) 1229 ($fh2, $rw)
1094} 1230}
1095 1231
1096package AnyEvent::Base; 1232package AnyEvent::Base;
1097 1233
1098# default implementations for many methods 1234# default implementations for many methods
1099 1235
1100BEGIN { 1236sub _time {
1237 # probe for availability of Time::HiRes
1101 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1238 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1239 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102 *_time = \&Time::HiRes::time; 1240 *_time = \&Time::HiRes::time;
1103 # if (eval "use POSIX (); (POSIX::times())... 1241 # if (eval "use POSIX (); (POSIX::times())...
1104 } else { 1242 } else {
1243 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105 *_time = sub { time }; # epic fail 1244 *_time = sub { time }; # epic fail
1106 } 1245 }
1246
1247 &_time
1107} 1248}
1108 1249
1109sub time { _time } 1250sub time { _time }
1110sub now { _time } 1251sub now { _time }
1111sub now_update { } 1252sub now_update { }
1116 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1257 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117} 1258}
1118 1259
1119# default implementation for ->signal 1260# default implementation for ->signal
1120 1261
1262our $HAVE_ASYNC_INTERRUPT;
1121our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1263our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1264our (%SIG_ASY, %SIG_ASY_W);
1265our ($SIG_COUNT, $SIG_TW);
1122 1266
1123sub _signal_exec { 1267sub _signal_exec {
1268 $HAVE_ASYNC_INTERRUPT
1269 ? $SIGPIPE_R->drain
1124 sysread $SIGPIPE_R, my $dummy, 4; 1270 : sysread $SIGPIPE_R, my $dummy, 9;
1125 1271
1126 while (%SIG_EV) { 1272 while (%SIG_EV) {
1127 for (keys %SIG_EV) { 1273 for (keys %SIG_EV) {
1128 delete $SIG_EV{$_}; 1274 delete $SIG_EV{$_};
1129 $_->() for values %{ $SIG_CB{$_} || {} }; 1275 $_->() for values %{ $SIG_CB{$_} || {} };
1130 } 1276 }
1131 } 1277 }
1132} 1278}
1133 1279
1280# install a dumym wakeupw atcher to reduce signal catching latency
1281sub _sig_add() {
1282 unless ($SIG_COUNT++) {
1283 # try to align timer on a full-second boundary, if possible
1284 my $NOW = AnyEvent->now;
1285
1286 $SIG_TW = AnyEvent->timer (
1287 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1288 interval => $MAX_SIGNAL_LATENCY,
1289 cb => sub { }, # just for the PERL_ASYNC_CHECK
1290 );
1291 }
1292}
1293
1294sub _sig_del {
1295 undef $SIG_TW
1296 unless --$SIG_COUNT;
1297}
1298
1299sub _signal {
1300 my (undef, %arg) = @_;
1301
1302 my $signal = uc $arg{signal}
1303 or Carp::croak "required option 'signal' is missing";
1304
1305 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1306
1307 if ($HAVE_ASYNC_INTERRUPT) {
1308 # async::interrupt
1309
1310 $SIG_ASY{$signal} ||= do {
1311 my $asy = new Async::Interrupt
1312 cb => sub { undef $SIG_EV{$signal} },
1313 signal => $signal,
1314 pipe => [$SIGPIPE_R->filenos],
1315 ;
1316 $asy->pipe_autodrain (0);
1317
1318 $asy
1319 };
1320
1321 } else {
1322 # pure perl
1323
1324 $SIG{$signal} ||= sub {
1325 local $!;
1326 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1327 undef $SIG_EV{$signal};
1328 };
1329
1330 # can't do signal processing without introducing races in pure perl,
1331 # so limit the signal latency.
1332 _sig_add;
1333 }
1334
1335 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1336}
1337
1134sub signal { 1338sub signal {
1135 my (undef, %arg) = @_; 1339 # probe for availability of Async::Interrupt
1340 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1341 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136 1342
1137 unless ($SIGPIPE_R) { 1343 $HAVE_ASYNC_INTERRUPT = 1;
1344 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1345 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1346
1347 } else {
1348 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1349
1138 require Fcntl; 1350 require Fcntl;
1139 1351
1140 if (AnyEvent::WIN32) { 1352 if (AnyEvent::WIN32) {
1141 require AnyEvent::Util; 1353 require AnyEvent::Util;
1142 1354
1157 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1369 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1158 1370
1159 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); 1371 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1160 } 1372 }
1161 1373
1162 my $signal = uc $arg{signal} 1374 *signal = \&_signal;
1163 or Carp::croak "required option 'signal' is missing"; 1375 &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, $arg{cb}], "AnyEvent::Base::signal"
1173} 1376}
1174 1377
1175sub AnyEvent::Base::signal::DESTROY { 1378sub AnyEvent::Base::signal::DESTROY {
1176 my ($signal, $cb) = @{$_[0]}; 1379 my ($signal, $cb) = @{$_[0]};
1177 1380
1381 _sig_del;
1382
1178 delete $SIG_CB{$signal}{$cb}; 1383 delete $SIG_CB{$signal}{$cb};
1179 1384
1385 $HAVE_ASYNC_INTERRUPT
1386 ? delete $SIG_ASY{$signal}
1180 # delete doesn't work with older perls - they then 1387 : # delete doesn't work with older perls - they then
1181 # print weird messages, or just unconditionally exit 1388 # print weird messages, or just unconditionally exit
1182 # instead of getting the default action. 1389 # instead of getting the default action.
1390 undef $SIG{$signal}
1183 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1391 unless keys %{ $SIG_CB{$signal} };
1184} 1392}
1185 1393
1186# default implementation for ->child 1394# default implementation for ->child
1187 1395
1188our %PID_CB; 1396our %PID_CB;
1190our $CHLD_DELAY_W; 1398our $CHLD_DELAY_W;
1191our $WNOHANG; 1399our $WNOHANG;
1192 1400
1193sub _sigchld { 1401sub _sigchld {
1194 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1402 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1403 $_->($pid, $?)
1195 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1404 for values %{ $PID_CB{$pid} || {} },
1196 (values %{ $PID_CB{0} || {} }); 1405 values %{ $PID_CB{0} || {} };
1197 } 1406 }
1198} 1407}
1199 1408
1200sub child { 1409sub child {
1201 my (undef, %arg) = @_; 1410 my (undef, %arg) = @_;
1203 defined (my $pid = $arg{pid} + 0) 1412 defined (my $pid = $arg{pid} + 0)
1204 or Carp::croak "required option 'pid' is missing"; 1413 or Carp::croak "required option 'pid' is missing";
1205 1414
1206 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1415 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207 1416
1417 # WNOHANG is almost cetrainly 1 everywhere
1418 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1419 ? 1
1208 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1420 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1209 1421
1210 unless ($CHLD_W) { 1422 unless ($CHLD_W) {
1211 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1423 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1212 # child could be a zombie already, so make at least one round 1424 # child could be a zombie already, so make at least one round
1213 &_sigchld; 1425 &_sigchld;
1265 1477
1266our @ISA = AnyEvent::CondVar::Base::; 1478our @ISA = AnyEvent::CondVar::Base::;
1267 1479
1268package AnyEvent::CondVar::Base; 1480package AnyEvent::CondVar::Base;
1269 1481
1270use overload 1482#use overload
1271 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1483# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272 fallback => 1; 1484# fallback => 1;
1485
1486# save 300+ kilobytes by dirtily hardcoding overloading
1487${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1488*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1489*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1490${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1491
1492our $WAITING;
1273 1493
1274sub _send { 1494sub _send {
1275 # nop 1495 # nop
1276} 1496}
1277 1497
1290sub ready { 1510sub ready {
1291 $_[0]{_ae_sent} 1511 $_[0]{_ae_sent}
1292} 1512}
1293 1513
1294sub _wait { 1514sub _wait {
1515 $WAITING
1516 and !$_[0]{_ae_sent}
1517 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1518
1519 local $WAITING = 1;
1295 AnyEvent->one_event while !$_[0]{_ae_sent}; 1520 AnyEvent->one_event while !$_[0]{_ae_sent};
1296} 1521}
1297 1522
1298sub recv { 1523sub recv {
1299 $_[0]->_wait; 1524 $_[0]->_wait;
1361C<PERL_ANYEVENT_MODEL>. 1586C<PERL_ANYEVENT_MODEL>.
1362 1587
1363When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1588When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364model it chooses. 1589model it chooses.
1365 1590
1591When set to C<8> or higher, then AnyEvent will report extra information on
1592which optional modules it loads and how it implements certain features.
1593
1366=item C<PERL_ANYEVENT_STRICT> 1594=item C<PERL_ANYEVENT_STRICT>
1367 1595
1368AnyEvent does not do much argument checking by default, as thorough 1596AnyEvent does not do much argument checking by default, as thorough
1369argument checking is very costly. Setting this variable to a true value 1597argument checking is very costly. Setting this variable to a true value
1370will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1598will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371check the arguments passed to most method calls. If it finds any problems 1599check the arguments passed to most method calls. If it finds any problems,
1372it will croak. 1600it will croak.
1373 1601
1374In other words, enables "strict" mode. 1602In other words, enables "strict" mode.
1375 1603
1376Unlike C<use strict>, it is definitely recommended ot keep it off in 1604Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1377production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1605>>, it is definitely recommended to keep it off in production. Keeping
1378developing programs can be very useful, however. 1606C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1607can be very useful, however.
1379 1608
1380=item C<PERL_ANYEVENT_MODEL> 1609=item C<PERL_ANYEVENT_MODEL>
1381 1610
1382This can be used to specify the event model to be used by AnyEvent, before 1611This 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 1612auto detection and -probing kicks in. It must be a string consisting
1426 1655
1427=item C<PERL_ANYEVENT_MAX_FORKS> 1656=item C<PERL_ANYEVENT_MAX_FORKS>
1428 1657
1429The maximum number of child processes that C<AnyEvent::Util::fork_call> 1658The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430will create in parallel. 1659will create in parallel.
1660
1661=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1662
1663The default value for the C<max_outstanding> parameter for the default DNS
1664resolver - this is the maximum number of parallel DNS requests that are
1665sent to the DNS server.
1666
1667=item C<PERL_ANYEVENT_RESOLV_CONF>
1668
1669The file to use instead of F</etc/resolv.conf> (or OS-specific
1670configuration) in the default resolver. When set to the empty string, no
1671default config will be used.
1672
1673=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1674
1675When neither C<ca_file> nor C<ca_path> was specified during
1676L<AnyEvent::TLS> context creation, and either of these environment
1677variables exist, they will be used to specify CA certificate locations
1678instead of a system-dependent default.
1679
1680=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1681
1682When these are set to C<1>, then the respective modules are not
1683loaded. Mostly good for testing AnyEvent itself.
1431 1684
1432=back 1685=back
1433 1686
1434=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1687=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435 1688
1680 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 1933 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 1934 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 1935 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 1936 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 1937 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1938 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
1939 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 1940 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 1941 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 1942 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 1943 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1689 1944
1718performance becomes really bad with lots of file descriptors (and few of 1973performance becomes really bad with lots of file descriptors (and few of
1719them active), of course, but this was not subject of this benchmark. 1974them active), of course, but this was not subject of this benchmark.
1720 1975
1721The C<Event> module has a relatively high setup and callback invocation 1976The C<Event> module has a relatively high setup and callback invocation
1722cost, but overall scores in on the third place. 1977cost, but overall scores in on the third place.
1978
1979C<IO::Async> performs admirably well, about on par with C<Event>, even
1980when using its pure perl backend.
1723 1981
1724C<Glib>'s memory usage is quite a bit higher, but it features a 1982C<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 1983faster callback invocation and overall ends up in the same class as
1726C<Event>. However, Glib scales extremely badly, doubling the number of 1984C<Event>. However, Glib scales extremely badly, doubling the number of
1727watchers increases the processing time by more than a factor of four, 1985watchers increases the processing time by more than a factor of four,
1805it to another server. This includes deleting the old timeout and creating 2063it to another server. This includes deleting the old timeout and creating
1806a new one that moves the timeout into the future. 2064a new one that moves the timeout into the future.
1807 2065
1808=head3 Results 2066=head3 Results
1809 2067
1810 name sockets create request 2068 name sockets create request
1811 EV 20000 69.01 11.16 2069 EV 20000 69.01 11.16
1812 Perl 20000 73.32 35.87 2070 Perl 20000 73.32 35.87
2071 IOAsync 20000 157.00 98.14 epoll
2072 IOAsync 20000 159.31 616.06 poll
1813 Event 20000 212.62 257.32 2073 Event 20000 212.62 257.32
1814 Glib 20000 651.16 1896.30 2074 Glib 20000 651.16 1896.30
1815 POE 20000 349.67 12317.24 uses POE::Loop::Event 2075 POE 20000 349.67 12317.24 uses POE::Loop::Event
1816 2076
1817=head3 Discussion 2077=head3 Discussion
1818 2078
1819This benchmark I<does> measure scalability and overall performance of the 2079This benchmark I<does> measure scalability and overall performance of the
1820particular event loop. 2080particular event loop.
1822EV is again fastest. Since it is using epoll on my system, the setup time 2082EV is again fastest. Since it is using epoll on my system, the setup time
1823is relatively high, though. 2083is relatively high, though.
1824 2084
1825Perl surprisingly comes second. It is much faster than the C-based event 2085Perl surprisingly comes second. It is much faster than the C-based event
1826loops Event and Glib. 2086loops Event and Glib.
2087
2088IO::Async performs very well when using its epoll backend, and still quite
2089good compared to Glib when using its pure perl backend.
1827 2090
1828Event suffers from high setup time as well (look at its code and you will 2091Event 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 2092understand why). Callback invocation also has a high overhead compared to
1830the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 2093the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831uses select or poll in basically all documented configurations. 2094uses select or poll in basically all documented configurations.
1900 2163
1901Recently I was told about the benchmark in the IO::Lambda manpage, which 2164Recently I was told about the benchmark in the IO::Lambda manpage, which
1902could be misinterpreted to make AnyEvent look bad. In fact, the benchmark 2165could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
1903simply compares IO::Lambda with POE, and IO::Lambda looks better (which 2166simply compares IO::Lambda with POE, and IO::Lambda looks better (which
1904shouldn't come as a surprise to anybody). As such, the benchmark is 2167shouldn'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 2168fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
1906optimal. But how would AnyEvent compare when used without the extra 2169very optimal. But how would AnyEvent compare when used without the extra
1907baggage? To explore this, I wrote the equivalent benchmark for AnyEvent. 2170baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
1908 2171
1909The benchmark itself creates an echo-server, and then, for 500 times, 2172The 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 2173connects 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 2174creates 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. 2175test the efficiency of the framework or much non-blocking I/O, but it is a
2176benchmark nevertheless.
1913 2177
1914 name runtime 2178 name runtime
1915 Lambda/select 0.330 sec 2179 Lambda/select 0.330 sec
1916 + optimized 0.122 sec 2180 + optimized 0.122 sec
1917 Lambda/AnyEvent 0.327 sec 2181 Lambda/AnyEvent 0.327 sec
1923 2187
1924 AnyEvent/select/nb 0.085 sec 2188 AnyEvent/select/nb 0.085 sec
1925 AnyEvent/EV/nb 0.068 sec 2189 AnyEvent/EV/nb 0.068 sec
1926 +state machine 0.134 sec 2190 +state machine 0.134 sec
1927 2191
1928The benchmark is also a bit unfair (my fault) - the IO::Lambda 2192The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
1929benchmarks actually make blocking connects and use 100% blocking I/O, 2193benchmarks actually make blocking connects and use 100% blocking I/O,
1930defeating the purpose of an event-based solution. All of the newly 2194defeating the purpose of an event-based solution. All of the newly
1931written AnyEvent benchmarks use 100% non-blocking connects (using 2195written AnyEvent benchmarks use 100% non-blocking connects (using
1932AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS 2196AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
1933resolver), so AnyEvent is at a disadvantage here as non-blocking connects 2197resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
1934generally require a lot more bookkeeping and event handling than blocking 2198generally require a lot more bookkeeping and event handling than blocking
1935connects (which involve a single syscall only). 2199connects (which involve a single syscall only).
1936 2200
1937The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which 2201The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
1938offers similar expressive power as POE and IO::Lambda (using conventional 2202offers similar expressive power as POE and IO::Lambda, using conventional
1939Perl syntax), which means both the echo server and the client are 100% 2203Perl 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. 2204non-blocking, further placing it at a disadvantage.
1941 2205
1942As you can see, AnyEvent + EV even beats the hand-optimised "raw sockets 2206As you can see, the AnyEvent + EV combination even beats the
1943benchmark", while AnyEvent + its pure perl backend easily beats 2207hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1944IO::Lambda and POE. 2208backend easily beats IO::Lambda and POE.
1945 2209
1946And even the 100% non-blocking version written using the high-level (and 2210And even the 100% non-blocking version written using the high-level (and
1947slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda, 2211slow :) 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 2212large margin, even though it does all of DNS, tcp-connect and socket I/O
1949non-blocking way. 2213in a non-blocking way.
2214
2215The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2216F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2217part of the IO::lambda distribution and were used without any changes.
1950 2218
1951 2219
1952=head1 SIGNALS 2220=head1 SIGNALS
1953 2221
1954AnyEvent currently installs handlers for these signals: 2222AnyEvent currently installs handlers for these signals:
1958=item SIGCHLD 2226=item SIGCHLD
1959 2227
1960A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2228A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1961emulation for event loops that do not support them natively. Also, some 2229emulation for event loops that do not support them natively. Also, some
1962event loops install a similar handler. 2230event loops install a similar handler.
2231
2232Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2233AnyEvent will reset it to default, to avoid losing child exit statuses.
1963 2234
1964=item SIGPIPE 2235=item SIGPIPE
1965 2236
1966A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2237A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1967when AnyEvent gets loaded. 2238when AnyEvent gets loaded.
1979 2250
1980=back 2251=back
1981 2252
1982=cut 2253=cut
1983 2254
2255undef $SIG{CHLD}
2256 if $SIG{CHLD} eq 'IGNORE';
2257
1984$SIG{PIPE} = sub { } 2258$SIG{PIPE} = sub { }
1985 unless defined $SIG{PIPE}; 2259 unless defined $SIG{PIPE};
2260
2261=head1 RECOMMENDED/OPTIONAL MODULES
2262
2263One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2264it's built-in modules) are required to use it.
2265
2266That does not mean that AnyEvent won't take advantage of some additional
2267modules if they are installed.
2268
2269This section epxlains which additional modules will be used, and how they
2270affect AnyEvent's operetion.
2271
2272=over 4
2273
2274=item L<Async::Interrupt>
2275
2276This slightly arcane module is used to implement fast signal handling: To
2277my knowledge, there is no way to do completely race-free and quick
2278signal handling in pure perl. To ensure that signals still get
2279delivered, AnyEvent will start an interval timer to wake up perl (and
2280catch the signals) with some delay (default is 10 seconds, look for
2281C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2282
2283If this module is available, then it will be used to implement signal
2284catching, which means that signals will not be delayed, and the event loop
2285will not be interrupted regularly, which is more efficient (And good for
2286battery life on laptops).
2287
2288This affects not just the pure-perl event loop, but also other event loops
2289that have no signal handling on their own (e.g. Glib, Tk, Qt).
2290
2291Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2292and either employ their own workarounds (POE) or use AnyEvent's workaround
2293(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2294does nothing for those backends.
2295
2296=item L<EV>
2297
2298This module isn't really "optional", as it is simply one of the backend
2299event loops that AnyEvent can use. However, it is simply the best event
2300loop available in terms of features, speed and stability: It supports
2301the AnyEvent API optimally, implements all the watcher types in XS, does
2302automatic timer adjustments even when no monotonic clock is available,
2303can take avdantage of advanced kernel interfaces such as C<epoll> and
2304C<kqueue>, and is the fastest backend I<by far>. You can even embed
2305L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2306
2307=item L<Guard>
2308
2309The guard module, when used, will be used to implement
2310C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2311lot less memory), but otherwise doesn't affect guard operation much. It is
2312purely used for performance.
2313
2314=item L<JSON> and L<JSON::XS>
2315
2316This module is required when you want to read or write JSON data via
2317L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2318advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2319
2320In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2321installed.
2322
2323=item L<Net::SSLeay>
2324
2325Implementing TLS/SSL in Perl is certainly interesting, but not very
2326worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2327the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2328
2329=item L<Time::HiRes>
2330
2331This module is part of perl since release 5.008. It will be used when the
2332chosen event library does not come with a timing source on it's own. The
2333pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2334try to use a monotonic clock for timing stability.
2335
2336=back
1986 2337
1987 2338
1988=head1 FORK 2339=head1 FORK
1989 2340
1990Most event libraries are not fork-safe. The ones who are usually are 2341Most 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> 2342because they rely on inefficient but fork-safe C<select> or C<poll>
1992calls. Only L<EV> is fully fork-aware. 2343calls. Only L<EV> is fully fork-aware.
1993 2344
1994If you have to fork, you must either do so I<before> creating your first 2345If 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. 2346watcher OR you must not use AnyEvent at all in the child OR you must do
2347something completely out of the scope of AnyEvent.
1996 2348
1997 2349
1998=head1 SECURITY CONSIDERATIONS 2350=head1 SECURITY CONSIDERATIONS
1999 2351
2000AnyEvent can be forced to load any event model via 2352AnyEvent can be forced to load any event model via
2014Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2366Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
2015be used to probe what backend is used and gain other information (which is 2367be used to probe what backend is used and gain other information (which is
2016probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2368probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
2017$ENV{PERL_ANYEVENT_STRICT}. 2369$ENV{PERL_ANYEVENT_STRICT}.
2018 2370
2371Note that AnyEvent will remove I<all> environment variables starting with
2372C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2373enabled.
2374
2019 2375
2020=head1 BUGS 2376=head1 BUGS
2021 2377
2022Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2378Perl 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 2379to work around. If you suffer from memleaks, first upgrade to Perl 5.10
2034L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2390L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2035 2391
2036Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2392Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2037L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2393L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2038L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2394L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2039L<AnyEvent::Impl::POE>. 2395L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
2040 2396
2041Non-blocking file handles, sockets, TCP clients and 2397Non-blocking file handles, sockets, TCP clients and
2042servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2398servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2043 2399
2044Asynchronous DNS: L<AnyEvent::DNS>. 2400Asynchronous DNS: L<AnyEvent::DNS>.
2045 2401
2046Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2402Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2403L<Coro::Event>,
2047 2404
2048Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2405Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2406L<AnyEvent::HTTP>.
2049 2407
2050 2408
2051=head1 AUTHOR 2409=head1 AUTHOR
2052 2410
2053 Marc Lehmann <schmorp@schmorp.de> 2411 Marc Lehmann <schmorp@schmorp.de>

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