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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 $guard = AnyEvent::post_detect { BLOCK }
753 868
754Arranges for the code block to be executed as soon as the event model is 869Arranges for the code block to be executed as soon as the event model is
755autodetected (or immediately if this has already happened). 870autodetected (or immediately if this has already happened).
756 871
872The block will be executed I<after> the actual backend has been detected
873(C<$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.
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 (or
885C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759L<Coro::BDB> for a case where this is useful. 886a case where this is useful.
887
888Example: Create a watcher for the IO::AIO module and store it in
889C<$WATCHER>. Only do so after the event loop is initialised, though.
890
891 our WATCHER;
892
893 my $guard = AnyEvent::post_detect {
894 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
895 };
896
897 # the ||= is important in case post_detect immediately runs the block,
898 # as to not clobber the newly-created watcher. assigning both watcher and
899 # post_detect guard to the same variable has the advantage of users being
900 # able to just C<undef $WATCHER> if the watcher causes them grief.
901
902 $WATCHER ||= $guard;
760 903
761=item @AnyEvent::post_detect 904=item @AnyEvent::post_detect
762 905
763If there are any code references in this array (you can C<push> to it 906If there are any code references in this array (you can C<push> to it
764before or after loading AnyEvent), then they will called directly after 907before or after loading AnyEvent), then they will called directly after
765the event loop has been chosen. 908the event loop has been chosen.
766 909
767You should check C<$AnyEvent::MODEL> before adding to this array, though: 910You 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, 911if it is defined then the event loop has already been detected, and the
769and the array will be ignored. 912array will be ignored.
770 913
771Best use C<AnyEvent::post_detect { BLOCK }> instead. 914Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
915it,as it takes care of these details.
916
917This variable is mainly useful for modules that can do something useful
918when AnyEvent is used and thus want to know when it is initialised, but do
919not need to even load it by default. This array provides the means to hook
920into AnyEvent passively, without loading it.
772 921
773=back 922=back
774 923
775=head1 WHAT TO DO IN A MODULE 924=head1 WHAT TO DO IN A MODULE
776 925
831 980
832 981
833=head1 OTHER MODULES 982=head1 OTHER MODULES
834 983
835The following is a non-exhaustive list of additional modules that use 984The following is a non-exhaustive list of additional modules that use
836AnyEvent and can therefore be mixed easily with other AnyEvent modules 985AnyEvent 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 986modules and other event loops in the same program. Some of the modules
838available via CPAN. 987come with AnyEvent, most are available via CPAN.
839 988
840=over 4 989=over 4
841 990
842=item L<AnyEvent::Util> 991=item L<AnyEvent::Util>
843 992
852 1001
853=item L<AnyEvent::Handle> 1002=item L<AnyEvent::Handle>
854 1003
855Provide read and write buffers, manages watchers for reads and writes, 1004Provide read and write buffers, manages watchers for reads and writes,
856supports raw and formatted I/O, I/O queued and fully transparent and 1005supports raw and formatted I/O, I/O queued and fully transparent and
857non-blocking SSL/TLS. 1006non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858 1007
859=item L<AnyEvent::DNS> 1008=item L<AnyEvent::DNS>
860 1009
861Provides rich asynchronous DNS resolver capabilities. 1010Provides rich asynchronous DNS resolver capabilities.
862 1011
890 1039
891=item L<AnyEvent::GPSD> 1040=item L<AnyEvent::GPSD>
892 1041
893A non-blocking interface to gpsd, a daemon delivering GPS information. 1042A non-blocking interface to gpsd, a daemon delivering GPS information.
894 1043
1044=item L<AnyEvent::IRC>
1045
1046AnyEvent based IRC client module family (replacing the older Net::IRC3).
1047
1048=item L<AnyEvent::XMPP>
1049
1050AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1051Net::XMPP2>.
1052
895=item L<AnyEvent::IGS> 1053=item L<AnyEvent::IGS>
896 1054
897A non-blocking interface to the Internet Go Server protocol (used by 1055A non-blocking interface to the Internet Go Server protocol (used by
898L<App::IGS>). 1056L<App::IGS>).
899 1057
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> 1058=item L<Net::FCP>
909 1059
910AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1060AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911of AnyEvent. 1061of AnyEvent.
912 1062
916 1066
917=item L<Coro> 1067=item L<Coro>
918 1068
919Has special support for AnyEvent via L<Coro::AnyEvent>. 1069Has special support for AnyEvent via L<Coro::AnyEvent>.
920 1070
921=item L<IO::Lambda>
922
923The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925=back 1071=back
926 1072
927=cut 1073=cut
928 1074
929package AnyEvent; 1075package AnyEvent;
930 1076
1077# basically a tuned-down version of common::sense
1078sub common_sense {
931no warnings; 1079 # no warnings
1080 ${^WARNING_BITS} ^= ${^WARNING_BITS};
932use strict qw(vars subs); 1081 # use strict vars subs
1082 $^H |= 0x00000600;
1083}
933 1084
1085BEGIN { AnyEvent::common_sense }
1086
934use Carp; 1087use Carp ();
935 1088
936our $VERSION = 4.411; 1089our $VERSION = 4.86;
937our $MODEL; 1090our $MODEL;
938 1091
939our $AUTOLOAD; 1092our $AUTOLOAD;
940our @ISA; 1093our @ISA;
941 1094
942our @REGISTRY; 1095our @REGISTRY;
943 1096
944our $WIN32; 1097our $WIN32;
945 1098
1099our $VERBOSE;
1100
946BEGIN { 1101BEGIN {
947 my $win32 = ! ! ($^O =~ /mswin32/i); 1102 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948 eval "sub WIN32(){ $win32 }"; 1103 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949}
950 1104
1105 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1106 if ${^TAINT};
1107
951our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1108 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1109
1110}
1111
1112our $MAX_SIGNAL_LATENCY = 10;
952 1113
953our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1114our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
954 1115
955{ 1116{
956 my $idx; 1117 my $idx;
964 [Event:: => AnyEvent::Impl::Event::], 1125 [Event:: => AnyEvent::Impl::Event::],
965 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1126 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
966 # everything below here will not be autoprobed 1127 # everything below here will not be autoprobed
967 # as the pureperl backend should work everywhere 1128 # as the pureperl backend should work everywhere
968 # and is usually faster 1129 # and is usually faster
969 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
970 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1130 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
971 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1131 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1132 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
972 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1133 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
973 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1134 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
974 [Wx:: => AnyEvent::Impl::POE::], 1135 [Wx:: => AnyEvent::Impl::POE::],
975 [Prima:: => AnyEvent::Impl::POE::], 1136 [Prima:: => AnyEvent::Impl::POE::],
1137 # IO::Async is just too broken - we would need workarounds for its
1138 # byzantine signal and broken child handling, among others.
1139 # IO::Async is rather hard to detect, as it doesn't have any
1140 # obvious default class.
1141# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1142# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1143# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
976); 1144);
977 1145
978our %method = map +($_ => 1), 1146our %method = map +($_ => 1),
979 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1147 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
980 1148
1000 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1168 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1001} 1169}
1002 1170
1003sub detect() { 1171sub detect() {
1004 unless ($MODEL) { 1172 unless ($MODEL) {
1005 no strict 'refs';
1006 local $SIG{__DIE__}; 1173 local $SIG{__DIE__};
1007 1174
1008 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1175 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1009 my $model = "AnyEvent::Impl::$1"; 1176 my $model = "AnyEvent::Impl::$1";
1010 if (eval "require $model") { 1177 if (eval "require $model") {
1011 $MODEL = $model; 1178 $MODEL = $model;
1012 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1179 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1013 } else { 1180 } else {
1014 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1181 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1015 } 1182 }
1016 } 1183 }
1017 1184
1018 # check for already loaded models 1185 # check for already loaded models
1019 unless ($MODEL) { 1186 unless ($MODEL) {
1020 for (@REGISTRY, @models) { 1187 for (@REGISTRY, @models) {
1021 my ($package, $model) = @$_; 1188 my ($package, $model) = @$_;
1022 if (${"$package\::VERSION"} > 0) { 1189 if (${"$package\::VERSION"} > 0) {
1023 if (eval "require $model") { 1190 if (eval "require $model") {
1024 $MODEL = $model; 1191 $MODEL = $model;
1025 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1192 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1026 last; 1193 last;
1027 } 1194 }
1028 } 1195 }
1029 } 1196 }
1030 1197
1035 my ($package, $model) = @$_; 1202 my ($package, $model) = @$_;
1036 if (eval "require $package" 1203 if (eval "require $package"
1037 and ${"$package\::VERSION"} > 0 1204 and ${"$package\::VERSION"} > 0
1038 and eval "require $model") { 1205 and eval "require $model") {
1039 $MODEL = $model; 1206 $MODEL = $model;
1040 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1207 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1041 last; 1208 last;
1042 } 1209 }
1043 } 1210 }
1044 1211
1045 $MODEL 1212 $MODEL
1061 1228
1062sub AUTOLOAD { 1229sub AUTOLOAD {
1063 (my $func = $AUTOLOAD) =~ s/.*://; 1230 (my $func = $AUTOLOAD) =~ s/.*://;
1064 1231
1065 $method{$func} 1232 $method{$func}
1066 or croak "$func: not a valid method for AnyEvent objects"; 1233 or Carp::croak "$func: not a valid method for AnyEvent objects";
1067 1234
1068 detect unless $MODEL; 1235 detect unless $MODEL;
1069 1236
1070 my $class = shift; 1237 my $class = shift;
1071 $class->$func (@_); 1238 $class->$func (@_);
1072} 1239}
1073 1240
1074# utility function to dup a filehandle. this is used by many backends 1241# utility function to dup a filehandle. this is used by many backends
1075# to support binding more than one watcher per filehandle (they usually 1242# to support binding more than one watcher per filehandle (they usually
1076# allow only one watcher per fd, so we dup it to get a different one). 1243# allow only one watcher per fd, so we dup it to get a different one).
1077sub _dupfh($$$$) { 1244sub _dupfh($$;$$) {
1078 my ($poll, $fh, $r, $w) = @_; 1245 my ($poll, $fh, $r, $w) = @_;
1079 1246
1080 # cygwin requires the fh mode to be matching, unix doesn't 1247 # cygwin requires the fh mode to be matching, unix doesn't
1081 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1248 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1082 : $poll eq "w" ? ($w, ">")
1083 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1084 1249
1085 open my $fh2, "$mode&" . fileno $fh 1250 open my $fh2, $mode, $fh
1086 or die "cannot dup() filehandle: $!,"; 1251 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1087 1252
1088 # we assume CLOEXEC is already set by perl in all important cases 1253 # we assume CLOEXEC is already set by perl in all important cases
1089 1254
1090 ($fh2, $rw) 1255 ($fh2, $rw)
1091} 1256}
1092 1257
1093package AnyEvent::Base; 1258package AnyEvent::Base;
1094 1259
1095# default implementations for many methods 1260# default implementations for many methods
1096 1261
1097BEGIN { 1262sub _time {
1263 # probe for availability of Time::HiRes
1098 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1264 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1265 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1099 *_time = \&Time::HiRes::time; 1266 *_time = \&Time::HiRes::time;
1100 # if (eval "use POSIX (); (POSIX::times())... 1267 # if (eval "use POSIX (); (POSIX::times())...
1101 } else { 1268 } else {
1269 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1102 *_time = sub { time }; # epic fail 1270 *_time = sub { time }; # epic fail
1103 } 1271 }
1272
1273 &_time
1104} 1274}
1105 1275
1106sub time { _time } 1276sub time { _time }
1107sub now { _time } 1277sub now { _time }
1108sub now_update { } 1278sub now_update { }
1113 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1283 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1114} 1284}
1115 1285
1116# default implementation for ->signal 1286# default implementation for ->signal
1117 1287
1288our $HAVE_ASYNC_INTERRUPT;
1118our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1289our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1290our (%SIG_ASY, %SIG_ASY_W);
1291our ($SIG_COUNT, $SIG_TW);
1119 1292
1120sub _signal_exec { 1293sub _signal_exec {
1294 $HAVE_ASYNC_INTERRUPT
1295 ? $SIGPIPE_R->drain
1121 sysread $SIGPIPE_R, my $dummy, 4; 1296 : sysread $SIGPIPE_R, my $dummy, 9;
1122 1297
1123 while (%SIG_EV) { 1298 while (%SIG_EV) {
1124 for (keys %SIG_EV) { 1299 for (keys %SIG_EV) {
1125 delete $SIG_EV{$_}; 1300 delete $SIG_EV{$_};
1126 $_->() for values %{ $SIG_CB{$_} || {} }; 1301 $_->() for values %{ $SIG_CB{$_} || {} };
1127 } 1302 }
1128 } 1303 }
1129} 1304}
1130 1305
1306# install a dumym wakeupw atcher to reduce signal catching latency
1307sub _sig_add() {
1308 unless ($SIG_COUNT++) {
1309 # try to align timer on a full-second boundary, if possible
1310 my $NOW = AnyEvent->now;
1311
1312 $SIG_TW = AnyEvent->timer (
1313 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1314 interval => $MAX_SIGNAL_LATENCY,
1315 cb => sub { }, # just for the PERL_ASYNC_CHECK
1316 );
1317 }
1318}
1319
1320sub _sig_del {
1321 undef $SIG_TW
1322 unless --$SIG_COUNT;
1323}
1324
1325sub _signal {
1326 my (undef, %arg) = @_;
1327
1328 my $signal = uc $arg{signal}
1329 or Carp::croak "required option 'signal' is missing";
1330
1331 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1332
1333 if ($HAVE_ASYNC_INTERRUPT) {
1334 # async::interrupt
1335
1336 $SIG_ASY{$signal} ||= do {
1337 my $asy = new Async::Interrupt
1338 cb => sub { undef $SIG_EV{$signal} },
1339 signal => $signal,
1340 pipe => [$SIGPIPE_R->filenos],
1341 ;
1342 $asy->pipe_autodrain (0);
1343
1344 $asy
1345 };
1346
1347 } else {
1348 # pure perl
1349
1350 $SIG{$signal} ||= sub {
1351 local $!;
1352 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1353 undef $SIG_EV{$signal};
1354 };
1355
1356 # can't do signal processing without introducing races in pure perl,
1357 # so limit the signal latency.
1358 _sig_add;
1359 }
1360
1361 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1362}
1363
1131sub signal { 1364sub signal {
1132 my (undef, %arg) = @_; 1365 # probe for availability of Async::Interrupt
1366 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1367 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1133 1368
1134 unless ($SIGPIPE_R) { 1369 $HAVE_ASYNC_INTERRUPT = 1;
1370 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1371 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1372
1373 } else {
1374 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1375
1135 require Fcntl; 1376 require Fcntl;
1136 1377
1137 if (AnyEvent::WIN32) { 1378 if (AnyEvent::WIN32) {
1138 require AnyEvent::Util; 1379 require AnyEvent::Util;
1139 1380
1154 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1395 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1155 1396
1156 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); 1397 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1157 } 1398 }
1158 1399
1159 my $signal = uc $arg{signal} 1400 *signal = \&_signal;
1160 or Carp::croak "required option 'signal' is missing"; 1401 &signal
1161
1162 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1163 $SIG{$signal} ||= sub {
1164 local $!;
1165 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1166 undef $SIG_EV{$signal};
1167 };
1168
1169 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1170} 1402}
1171 1403
1172sub AnyEvent::Base::signal::DESTROY { 1404sub AnyEvent::Base::signal::DESTROY {
1173 my ($signal, $cb) = @{$_[0]}; 1405 my ($signal, $cb) = @{$_[0]};
1174 1406
1407 _sig_del;
1408
1175 delete $SIG_CB{$signal}{$cb}; 1409 delete $SIG_CB{$signal}{$cb};
1176 1410
1411 $HAVE_ASYNC_INTERRUPT
1412 ? delete $SIG_ASY{$signal}
1177 # delete doesn't work with older perls - they then 1413 : # delete doesn't work with older perls - they then
1178 # print weird messages, or just unconditionally exit 1414 # print weird messages, or just unconditionally exit
1179 # instead of getting the default action. 1415 # instead of getting the default action.
1416 undef $SIG{$signal}
1180 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1417 unless keys %{ $SIG_CB{$signal} };
1181} 1418}
1182 1419
1183# default implementation for ->child 1420# default implementation for ->child
1184 1421
1185our %PID_CB; 1422our %PID_CB;
1187our $CHLD_DELAY_W; 1424our $CHLD_DELAY_W;
1188our $WNOHANG; 1425our $WNOHANG;
1189 1426
1190sub _sigchld { 1427sub _sigchld {
1191 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1428 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1429 $_->($pid, $?)
1192 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1430 for values %{ $PID_CB{$pid} || {} },
1193 (values %{ $PID_CB{0} || {} }); 1431 values %{ $PID_CB{0} || {} };
1194 } 1432 }
1195} 1433}
1196 1434
1197sub child { 1435sub child {
1198 my (undef, %arg) = @_; 1436 my (undef, %arg) = @_;
1200 defined (my $pid = $arg{pid} + 0) 1438 defined (my $pid = $arg{pid} + 0)
1201 or Carp::croak "required option 'pid' is missing"; 1439 or Carp::croak "required option 'pid' is missing";
1202 1440
1203 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1441 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1204 1442
1443 # WNOHANG is almost cetrainly 1 everywhere
1444 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1445 ? 1
1205 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1446 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1206 1447
1207 unless ($CHLD_W) { 1448 unless ($CHLD_W) {
1208 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1449 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1209 # child could be a zombie already, so make at least one round 1450 # child could be a zombie already, so make at least one round
1210 &_sigchld; 1451 &_sigchld;
1262 1503
1263our @ISA = AnyEvent::CondVar::Base::; 1504our @ISA = AnyEvent::CondVar::Base::;
1264 1505
1265package AnyEvent::CondVar::Base; 1506package AnyEvent::CondVar::Base;
1266 1507
1267use overload 1508#use overload
1268 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1509# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1269 fallback => 1; 1510# fallback => 1;
1511
1512# save 300+ kilobytes by dirtily hardcoding overloading
1513${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1514*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1515*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1516${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1517
1518our $WAITING;
1270 1519
1271sub _send { 1520sub _send {
1272 # nop 1521 # nop
1273} 1522}
1274 1523
1287sub ready { 1536sub ready {
1288 $_[0]{_ae_sent} 1537 $_[0]{_ae_sent}
1289} 1538}
1290 1539
1291sub _wait { 1540sub _wait {
1541 $WAITING
1542 and !$_[0]{_ae_sent}
1543 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1544
1545 local $WAITING = 1;
1292 AnyEvent->one_event while !$_[0]{_ae_sent}; 1546 AnyEvent->one_event while !$_[0]{_ae_sent};
1293} 1547}
1294 1548
1295sub recv { 1549sub recv {
1296 $_[0]->_wait; 1550 $_[0]->_wait;
1337so on. 1591so on.
1338 1592
1339=head1 ENVIRONMENT VARIABLES 1593=head1 ENVIRONMENT VARIABLES
1340 1594
1341The following environment variables are used by this module or its 1595The following environment variables are used by this module or its
1342submodules: 1596submodules.
1597
1598Note that AnyEvent will remove I<all> environment variables starting with
1599C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
1600enabled.
1343 1601
1344=over 4 1602=over 4
1345 1603
1346=item C<PERL_ANYEVENT_VERBOSE> 1604=item C<PERL_ANYEVENT_VERBOSE>
1347 1605
1354C<PERL_ANYEVENT_MODEL>. 1612C<PERL_ANYEVENT_MODEL>.
1355 1613
1356When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1614When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1357model it chooses. 1615model it chooses.
1358 1616
1617When set to C<8> or higher, then AnyEvent will report extra information on
1618which optional modules it loads and how it implements certain features.
1619
1359=item C<PERL_ANYEVENT_STRICT> 1620=item C<PERL_ANYEVENT_STRICT>
1360 1621
1361AnyEvent does not do much argument checking by default, as thorough 1622AnyEvent does not do much argument checking by default, as thorough
1362argument checking is very costly. Setting this variable to a true value 1623argument checking is very costly. Setting this variable to a true value
1363will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1624will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1364check the arguments passed to most method calls. If it finds any problems 1625check the arguments passed to most method calls. If it finds any problems,
1365it will croak. 1626it will croak.
1366 1627
1367In other words, enables "strict" mode. 1628In other words, enables "strict" mode.
1368 1629
1369Unlike C<use strict>, it is definitely recommended ot keep it off in 1630Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1370production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1631>>, it is definitely recommended to keep it off in production. Keeping
1371developing programs can be very useful, however. 1632C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1633can be very useful, however.
1372 1634
1373=item C<PERL_ANYEVENT_MODEL> 1635=item C<PERL_ANYEVENT_MODEL>
1374 1636
1375This can be used to specify the event model to be used by AnyEvent, before 1637This can be used to specify the event model to be used by AnyEvent, before
1376auto detection and -probing kicks in. It must be a string consisting 1638auto detection and -probing kicks in. It must be a string consisting
1419 1681
1420=item C<PERL_ANYEVENT_MAX_FORKS> 1682=item C<PERL_ANYEVENT_MAX_FORKS>
1421 1683
1422The maximum number of child processes that C<AnyEvent::Util::fork_call> 1684The maximum number of child processes that C<AnyEvent::Util::fork_call>
1423will create in parallel. 1685will create in parallel.
1686
1687=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1688
1689The default value for the C<max_outstanding> parameter for the default DNS
1690resolver - this is the maximum number of parallel DNS requests that are
1691sent to the DNS server.
1692
1693=item C<PERL_ANYEVENT_RESOLV_CONF>
1694
1695The file to use instead of F</etc/resolv.conf> (or OS-specific
1696configuration) in the default resolver. When set to the empty string, no
1697default config will be used.
1698
1699=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1700
1701When neither C<ca_file> nor C<ca_path> was specified during
1702L<AnyEvent::TLS> context creation, and either of these environment
1703variables exist, they will be used to specify CA certificate locations
1704instead of a system-dependent default.
1705
1706=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1707
1708When these are set to C<1>, then the respective modules are not
1709loaded. Mostly good for testing AnyEvent itself.
1424 1710
1425=back 1711=back
1426 1712
1427=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1713=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1428 1714
1673 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 1959 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1674 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 1960 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1675 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 1961 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1676 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 1962 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1677 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 1963 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1964 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
1965 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1678 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 1966 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1679 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 1967 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1680 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 1968 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1681 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 1969 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1682 1970
1711performance becomes really bad with lots of file descriptors (and few of 1999performance becomes really bad with lots of file descriptors (and few of
1712them active), of course, but this was not subject of this benchmark. 2000them active), of course, but this was not subject of this benchmark.
1713 2001
1714The C<Event> module has a relatively high setup and callback invocation 2002The C<Event> module has a relatively high setup and callback invocation
1715cost, but overall scores in on the third place. 2003cost, but overall scores in on the third place.
2004
2005C<IO::Async> performs admirably well, about on par with C<Event>, even
2006when using its pure perl backend.
1716 2007
1717C<Glib>'s memory usage is quite a bit higher, but it features a 2008C<Glib>'s memory usage is quite a bit higher, but it features a
1718faster callback invocation and overall ends up in the same class as 2009faster callback invocation and overall ends up in the same class as
1719C<Event>. However, Glib scales extremely badly, doubling the number of 2010C<Event>. However, Glib scales extremely badly, doubling the number of
1720watchers increases the processing time by more than a factor of four, 2011watchers increases the processing time by more than a factor of four,
1798it to another server. This includes deleting the old timeout and creating 2089it to another server. This includes deleting the old timeout and creating
1799a new one that moves the timeout into the future. 2090a new one that moves the timeout into the future.
1800 2091
1801=head3 Results 2092=head3 Results
1802 2093
1803 name sockets create request 2094 name sockets create request
1804 EV 20000 69.01 11.16 2095 EV 20000 69.01 11.16
1805 Perl 20000 73.32 35.87 2096 Perl 20000 73.32 35.87
2097 IOAsync 20000 157.00 98.14 epoll
2098 IOAsync 20000 159.31 616.06 poll
1806 Event 20000 212.62 257.32 2099 Event 20000 212.62 257.32
1807 Glib 20000 651.16 1896.30 2100 Glib 20000 651.16 1896.30
1808 POE 20000 349.67 12317.24 uses POE::Loop::Event 2101 POE 20000 349.67 12317.24 uses POE::Loop::Event
1809 2102
1810=head3 Discussion 2103=head3 Discussion
1811 2104
1812This benchmark I<does> measure scalability and overall performance of the 2105This benchmark I<does> measure scalability and overall performance of the
1813particular event loop. 2106particular event loop.
1815EV is again fastest. Since it is using epoll on my system, the setup time 2108EV is again fastest. Since it is using epoll on my system, the setup time
1816is relatively high, though. 2109is relatively high, though.
1817 2110
1818Perl surprisingly comes second. It is much faster than the C-based event 2111Perl surprisingly comes second. It is much faster than the C-based event
1819loops Event and Glib. 2112loops Event and Glib.
2113
2114IO::Async performs very well when using its epoll backend, and still quite
2115good compared to Glib when using its pure perl backend.
1820 2116
1821Event suffers from high setup time as well (look at its code and you will 2117Event suffers from high setup time as well (look at its code and you will
1822understand why). Callback invocation also has a high overhead compared to 2118understand why). Callback invocation also has a high overhead compared to
1823the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 2119the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1824uses select or poll in basically all documented configurations. 2120uses select or poll in basically all documented configurations.
1887=item * C-based event loops perform very well with small number of 2183=item * C-based event loops perform very well with small number of
1888watchers, as the management overhead dominates. 2184watchers, as the management overhead dominates.
1889 2185
1890=back 2186=back
1891 2187
2188=head2 THE IO::Lambda BENCHMARK
2189
2190Recently I was told about the benchmark in the IO::Lambda manpage, which
2191could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
2192simply compares IO::Lambda with POE, and IO::Lambda looks better (which
2193shouldn't come as a surprise to anybody). As such, the benchmark is
2194fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
2195very optimal. But how would AnyEvent compare when used without the extra
2196baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
2197
2198The benchmark itself creates an echo-server, and then, for 500 times,
2199connects to the echo server, sends a line, waits for the reply, and then
2200creates the next connection. This is a rather bad benchmark, as it doesn't
2201test the efficiency of the framework or much non-blocking I/O, but it is a
2202benchmark nevertheless.
2203
2204 name runtime
2205 Lambda/select 0.330 sec
2206 + optimized 0.122 sec
2207 Lambda/AnyEvent 0.327 sec
2208 + optimized 0.138 sec
2209 Raw sockets/select 0.077 sec
2210 POE/select, components 0.662 sec
2211 POE/select, raw sockets 0.226 sec
2212 POE/select, optimized 0.404 sec
2213
2214 AnyEvent/select/nb 0.085 sec
2215 AnyEvent/EV/nb 0.068 sec
2216 +state machine 0.134 sec
2217
2218The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
2219benchmarks actually make blocking connects and use 100% blocking I/O,
2220defeating the purpose of an event-based solution. All of the newly
2221written AnyEvent benchmarks use 100% non-blocking connects (using
2222AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
2223resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
2224generally require a lot more bookkeeping and event handling than blocking
2225connects (which involve a single syscall only).
2226
2227The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
2228offers similar expressive power as POE and IO::Lambda, using conventional
2229Perl syntax. This means that both the echo server and the client are 100%
2230non-blocking, further placing it at a disadvantage.
2231
2232As you can see, the AnyEvent + EV combination even beats the
2233hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2234backend easily beats IO::Lambda and POE.
2235
2236And even the 100% non-blocking version written using the high-level (and
2237slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
2238large margin, even though it does all of DNS, tcp-connect and socket I/O
2239in a non-blocking way.
2240
2241The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2242F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2243part of the IO::lambda distribution and were used without any changes.
2244
1892 2245
1893=head1 SIGNALS 2246=head1 SIGNALS
1894 2247
1895AnyEvent currently installs handlers for these signals: 2248AnyEvent currently installs handlers for these signals:
1896 2249
1899=item SIGCHLD 2252=item SIGCHLD
1900 2253
1901A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2254A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1902emulation for event loops that do not support them natively. Also, some 2255emulation for event loops that do not support them natively. Also, some
1903event loops install a similar handler. 2256event loops install a similar handler.
2257
2258Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2259AnyEvent will reset it to default, to avoid losing child exit statuses.
1904 2260
1905=item SIGPIPE 2261=item SIGPIPE
1906 2262
1907A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2263A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1908when AnyEvent gets loaded. 2264when AnyEvent gets loaded.
1920 2276
1921=back 2277=back
1922 2278
1923=cut 2279=cut
1924 2280
2281undef $SIG{CHLD}
2282 if $SIG{CHLD} eq 'IGNORE';
2283
1925$SIG{PIPE} = sub { } 2284$SIG{PIPE} = sub { }
1926 unless defined $SIG{PIPE}; 2285 unless defined $SIG{PIPE};
2286
2287=head1 RECOMMENDED/OPTIONAL MODULES
2288
2289One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2290it's built-in modules) are required to use it.
2291
2292That does not mean that AnyEvent won't take advantage of some additional
2293modules if they are installed.
2294
2295This section epxlains which additional modules will be used, and how they
2296affect AnyEvent's operetion.
2297
2298=over 4
2299
2300=item L<Async::Interrupt>
2301
2302This slightly arcane module is used to implement fast signal handling: To
2303my knowledge, there is no way to do completely race-free and quick
2304signal handling in pure perl. To ensure that signals still get
2305delivered, AnyEvent will start an interval timer to wake up perl (and
2306catch the signals) with some delay (default is 10 seconds, look for
2307C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2308
2309If this module is available, then it will be used to implement signal
2310catching, which means that signals will not be delayed, and the event loop
2311will not be interrupted regularly, which is more efficient (And good for
2312battery life on laptops).
2313
2314This affects not just the pure-perl event loop, but also other event loops
2315that have no signal handling on their own (e.g. Glib, Tk, Qt).
2316
2317Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2318and either employ their own workarounds (POE) or use AnyEvent's workaround
2319(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2320does nothing for those backends.
2321
2322=item L<EV>
2323
2324This module isn't really "optional", as it is simply one of the backend
2325event loops that AnyEvent can use. However, it is simply the best event
2326loop available in terms of features, speed and stability: It supports
2327the AnyEvent API optimally, implements all the watcher types in XS, does
2328automatic timer adjustments even when no monotonic clock is available,
2329can take avdantage of advanced kernel interfaces such as C<epoll> and
2330C<kqueue>, and is the fastest backend I<by far>. You can even embed
2331L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2332
2333=item L<Guard>
2334
2335The guard module, when used, will be used to implement
2336C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2337lot less memory), but otherwise doesn't affect guard operation much. It is
2338purely used for performance.
2339
2340=item L<JSON> and L<JSON::XS>
2341
2342This module is required when you want to read or write JSON data via
2343L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2344advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2345
2346In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2347installed.
2348
2349=item L<Net::SSLeay>
2350
2351Implementing TLS/SSL in Perl is certainly interesting, but not very
2352worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2353the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2354
2355=item L<Time::HiRes>
2356
2357This module is part of perl since release 5.008. It will be used when the
2358chosen event library does not come with a timing source on it's own. The
2359pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2360try to use a monotonic clock for timing stability.
2361
2362=back
1927 2363
1928 2364
1929=head1 FORK 2365=head1 FORK
1930 2366
1931Most event libraries are not fork-safe. The ones who are usually are 2367Most event libraries are not fork-safe. The ones who are usually are
1932because they rely on inefficient but fork-safe C<select> or C<poll> 2368because they rely on inefficient but fork-safe C<select> or C<poll>
1933calls. Only L<EV> is fully fork-aware. 2369calls. Only L<EV> is fully fork-aware.
1934 2370
1935If you have to fork, you must either do so I<before> creating your first 2371If you have to fork, you must either do so I<before> creating your first
1936watcher OR you must not use AnyEvent at all in the child. 2372watcher OR you must not use AnyEvent at all in the child OR you must do
2373something completely out of the scope of AnyEvent.
1937 2374
1938 2375
1939=head1 SECURITY CONSIDERATIONS 2376=head1 SECURITY CONSIDERATIONS
1940 2377
1941AnyEvent can be forced to load any event model via 2378AnyEvent can be forced to load any event model via
1955Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2392Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1956be used to probe what backend is used and gain other information (which is 2393be used to probe what backend is used and gain other information (which is
1957probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2394probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1958$ENV{PERL_ANYEVENT_STRICT}. 2395$ENV{PERL_ANYEVENT_STRICT}.
1959 2396
2397Note that AnyEvent will remove I<all> environment variables starting with
2398C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2399enabled.
2400
1960 2401
1961=head1 BUGS 2402=head1 BUGS
1962 2403
1963Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2404Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1964to work around. If you suffer from memleaks, first upgrade to Perl 5.10 2405to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1975L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2416L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1976 2417
1977Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2418Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1978L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2419L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1979L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2420L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1980L<AnyEvent::Impl::POE>. 2421L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1981 2422
1982Non-blocking file handles, sockets, TCP clients and 2423Non-blocking file handles, sockets, TCP clients and
1983servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2424servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1984 2425
1985Asynchronous DNS: L<AnyEvent::DNS>. 2426Asynchronous DNS: L<AnyEvent::DNS>.
1986 2427
1987Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2428Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2429L<Coro::Event>,
1988 2430
1989Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2431Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2432L<AnyEvent::HTTP>.
1990 2433
1991 2434
1992=head1 AUTHOR 2435=head1 AUTHOR
1993 2436
1994 Marc Lehmann <schmorp@schmorp.de> 2437 Marc Lehmann <schmorp@schmorp.de>

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