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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, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
6event loops.
6 7
7=head1 SYNOPSIS 8=head1 SYNOPSIS
8 9
9 use AnyEvent; 10 use AnyEvent;
10 11
39=head1 INTRODUCTION/TUTORIAL 40=head1 INTRODUCTION/TUTORIAL
40 41
41This manpage is mainly a reference manual. If you are interested 42This manpage is mainly a reference manual. If you are interested
42in a tutorial or some gentle introduction, have a look at the 43in a tutorial or some gentle introduction, have a look at the
43L<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.
44 53
45=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
46 55
47Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
48nowadays. So what is different about AnyEvent? 57nowadays. So what is different about AnyEvent?
175=head2 I/O WATCHERS 184=head2 I/O WATCHERS
176 185
177You 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
178with the following mandatory key-value pairs as arguments: 187with the following mandatory key-value pairs as arguments:
179 188
180C<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
181for 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
182handle). Note that only file handles pointing to things for which 191handle). Note that only file handles pointing to things for which
183non-blocking operation makes sense are allowed. This includes sockets, 192non-blocking operation makes sense are allowed. This includes sockets,
184most 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
185or block devices. 194or block devices.
360invocation, and callback invocation will be synchronous. Synchronous means 369invocation, and callback invocation will be synchronous. Synchronous means
361that 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,
362but it is guaranteed not to interrupt any other callbacks. 371but it is guaranteed not to interrupt any other callbacks.
363 372
364The 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
365between multiple watchers. 374between multiple watchers, and AnyEvent will ensure that signals will not
375interrupt your program at bad times.
366 376
367This watcher might use C<%SIG>, so programs overwriting those signals 377This watcher might use C<%SIG> (depending on the event loop used),
368directly will likely not work correctly. 378so programs overwriting those signals directly will likely not work
379correctly.
369 380
370Example: exit on SIGINT 381Example: exit on SIGINT
371 382
372 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.
373 400
374=head2 CHILD PROCESS WATCHERS 401=head2 CHILD PROCESS WATCHERS
375 402
376You 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.
377 404
391 418
392There 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
393I<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
394have exited already (and no SIGCHLD will be sent anymore). 421have exited already (and no SIGCHLD will be sent anymore).
395 422
396Not 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
397event 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
398loaded 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.
399 429
400This 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
401AnyEvent 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
402C<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.
403 438
404Example: fork a process and wait for it 439Example: fork a process and wait for it
405 440
406 my $done = AnyEvent->condvar; 441 my $done = AnyEvent->condvar;
407 442
458 493
459If 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
460require you to run some blocking "loop", "run" or similar function that 495require you to run some blocking "loop", "run" or similar function that
461will actively watch for new events and call your callbacks. 496will actively watch for new events and call your callbacks.
462 497
463AnyEvent is different, it expects somebody else to run the event loop and 498AnyEvent is slightly different: it expects somebody else to run the event
464will only block when necessary (usually when told by the user). 499loop and will only block when necessary (usually when told by the user).
465 500
466The instrument to do that is called a "condition variable", so called 501The instrument to do that is called a "condition variable", so called
467because they represent a condition that must become true. 502because they represent a condition that must become true.
468 503
504Now is probably a good time to look at the examples further below.
505
469Condition variables can be created by calling the C<< AnyEvent->condvar 506Condition variables can be created by calling the C<< AnyEvent->condvar
470>> method, usually without arguments. The only argument pair allowed is 507>> method, usually without arguments. The only argument pair allowed is
471
472C<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
473becomes true, with the condition variable as the first argument (but not 509becomes true, with the condition variable as the first argument (but not
474the results). 510the results).
475 511
476After creation, the condition variable is "false" until it becomes "true" 512After creation, the condition variable is "false" until it becomes "true"
525 after => 1, 561 after => 1,
526 cb => sub { $result_ready->send }, 562 cb => sub { $result_ready->send },
527 ); 563 );
528 564
529 # this "blocks" (while handling events) till the callback 565 # this "blocks" (while handling events) till the callback
530 # calls send 566 # calls -<send
531 $result_ready->recv; 567 $result_ready->recv;
532 568
533Example: wait for a timer, but take advantage of the fact that 569Example: wait for a timer, but take advantage of the fact that condition
534condition variables are also code references. 570variables are also callable directly.
535 571
536 my $done = AnyEvent->condvar; 572 my $done = AnyEvent->condvar;
537 my $delay = AnyEvent->timer (after => 5, cb => $done); 573 my $delay = AnyEvent->timer (after => 5, cb => $done);
538 $done->recv; 574 $done->recv;
539 575
545 581
546 ... 582 ...
547 583
548 my @info = $couchdb->info->recv; 584 my @info = $couchdb->info->recv;
549 585
550And this is how you would just ste a callback to be called whenever the 586And this is how you would just set a callback to be called whenever the
551results are available: 587results are available:
552 588
553 $couchdb->info->cb (sub { 589 $couchdb->info->cb (sub {
554 my @info = $_[0]->recv; 590 my @info = $_[0]->recv;
555 }); 591 });
573immediately from within send. 609immediately from within send.
574 610
575Any arguments passed to the C<send> call will be returned by all 611Any arguments passed to the C<send> call will be returned by all
576future C<< ->recv >> calls. 612future C<< ->recv >> calls.
577 613
578Condition variables are overloaded so one can call them directly 614Condition variables are overloaded so one can call them directly (as if
579(as a code reference). Calling them directly is the same as calling 615they were a code reference). Calling them directly is the same as calling
580C<send>. Note, however, that many C-based event loops do not handle 616C<send>.
581overloading, so as tempting as it may be, passing a condition variable
582instead of a callback does not work. Both the pure perl and EV loops
583support overloading, however, as well as all functions that use perl to
584invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
585example).
586 617
587=item $cv->croak ($error) 618=item $cv->croak ($error)
588 619
589Similar to send, but causes all call's to C<< ->recv >> to invoke 620Similar to send, but causes all call's to C<< ->recv >> to invoke
590C<Carp::croak> with the given error message/object/scalar. 621C<Carp::croak> with the given error message/object/scalar.
591 622
592This can be used to signal any errors to the condition variable 623This can be used to signal any errors to the condition variable
593user/consumer. 624user/consumer. Doing it this way instead of calling C<croak> directly
625delays the error detetcion, but has the overwhelmign advantage that it
626diagnoses the error at the place where the result is expected, and not
627deep in some event clalback without connection to the actual code causing
628the problem.
594 629
595=item $cv->begin ([group callback]) 630=item $cv->begin ([group callback])
596 631
597=item $cv->end 632=item $cv->end
598
599These two methods are EXPERIMENTAL and MIGHT CHANGE.
600 633
601These two methods can be used to combine many transactions/events into 634These two methods can be used to combine many transactions/events into
602one. For example, a function that pings many hosts in parallel might want 635one. For example, a function that pings many hosts in parallel might want
603to use a condition variable for the whole process. 636to use a condition variable for the whole process.
604 637
606C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 639C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
607>>, the (last) callback passed to C<begin> will be executed. That callback 640>>, the (last) callback passed to C<begin> will be executed. That callback
608is I<supposed> to call C<< ->send >>, but that is not required. If no 641is I<supposed> to call C<< ->send >>, but that is not required. If no
609callback was set, C<send> will be called without any arguments. 642callback was set, C<send> will be called without any arguments.
610 643
611Let's clarify this with the ping example: 644You can think of C<< $cv->send >> giving you an OR condition (one call
645sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
646condition (all C<begin> calls must be C<end>'ed before the condvar sends).
647
648Let's start with a simple example: you have two I/O watchers (for example,
649STDOUT and STDERR for a program), and you want to wait for both streams to
650close before activating a condvar:
651
652 my $cv = AnyEvent->condvar;
653
654 $cv->begin; # first watcher
655 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
656 defined sysread $fh1, my $buf, 4096
657 or $cv->end;
658 });
659
660 $cv->begin; # second watcher
661 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
662 defined sysread $fh2, my $buf, 4096
663 or $cv->end;
664 });
665
666 $cv->recv;
667
668This works because for every event source (EOF on file handle), there is
669one call to C<begin>, so the condvar waits for all calls to C<end> before
670sending.
671
672The ping example mentioned above is slightly more complicated, as the
673there are results to be passwd back, and the number of tasks that are
674begung can potentially be zero:
612 675
613 my $cv = AnyEvent->condvar; 676 my $cv = AnyEvent->condvar;
614 677
615 my %result; 678 my %result;
616 $cv->begin (sub { $cv->send (\%result) }); 679 $cv->begin (sub { $cv->send (\%result) });
636loop, which serves two important purposes: first, it sets the callback 699loop, which serves two important purposes: first, it sets the callback
637to be called once the counter reaches C<0>, and second, it ensures that 700to be called once the counter reaches C<0>, and second, it ensures that
638C<send> is called even when C<no> hosts are being pinged (the loop 701C<send> is called even when C<no> hosts are being pinged (the loop
639doesn't execute once). 702doesn't execute once).
640 703
641This is the general pattern when you "fan out" into multiple subrequests: 704This is the general pattern when you "fan out" into multiple (but
642use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 705potentially none) subrequests: use an outer C<begin>/C<end> pair to set
643is called at least once, and then, for each subrequest you start, call 706the callback and ensure C<end> is called at least once, and then, for each
644C<begin> and for each subrequest you finish, call C<end>. 707subrequest you start, call C<begin> and for each subrequest you finish,
708call C<end>.
645 709
646=back 710=back
647 711
648=head3 METHODS FOR CONSUMERS 712=head3 METHODS FOR CONSUMERS
649 713
665function will call C<croak>. 729function will call C<croak>.
666 730
667In list context, all parameters passed to C<send> will be returned, 731In list context, all parameters passed to C<send> will be returned,
668in scalar context only the first one will be returned. 732in scalar context only the first one will be returned.
669 733
734Note that doing a blocking wait in a callback is not supported by any
735event loop, that is, recursive invocation of a blocking C<< ->recv
736>> is not allowed, and the C<recv> call will C<croak> if such a
737condition is detected. This condition can be slightly loosened by using
738L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
739any thread that doesn't run the event loop itself.
740
670Not all event models support a blocking wait - some die in that case 741Not all event models support a blocking wait - some die in that case
671(programs might want to do that to stay interactive), so I<if you are 742(programs might want to do that to stay interactive), so I<if you are
672using this from a module, never require a blocking wait>, but let the 743using this from a module, never require a blocking wait>. Instead, let the
673caller decide whether the call will block or not (for example, by coupling 744caller decide whether the call will block or not (for example, by coupling
674condition variables with some kind of request results and supporting 745condition variables with some kind of request results and supporting
675callbacks so the caller knows that getting the result will not block, 746callbacks so the caller knows that getting the result will not block,
676while still supporting blocking waits if the caller so desires). 747while still supporting blocking waits if the caller so desires).
677 748
678Another reason I<never> to C<< ->recv >> in a module is that you cannot
679sensibly have two C<< ->recv >>'s in parallel, as that would require
680multiple interpreters or coroutines/threads, none of which C<AnyEvent>
681can supply.
682
683The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
684fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
685versions and also integrates coroutines into AnyEvent, making blocking
686C<< ->recv >> calls perfectly safe as long as they are done from another
687coroutine (one that doesn't run the event loop).
688
689You can ensure that C<< -recv >> never blocks by setting a callback and 749You can ensure that C<< -recv >> never blocks by setting a callback and
690only calling C<< ->recv >> from within that callback (or at a later 750only calling C<< ->recv >> from within that callback (or at a later
691time). This will work even when the event loop does not support blocking 751time). This will work even when the event loop does not support blocking
692waits otherwise. 752waits otherwise.
693 753
706variable itself. Calling C<recv> inside the callback or at any later time 766variable itself. Calling C<recv> inside the callback or at any later time
707is guaranteed not to block. 767is guaranteed not to block.
708 768
709=back 769=back
710 770
771=head1 SUPPORTED EVENT LOOPS/BACKENDS
772
773The available backend classes are (every class has its own manpage):
774
775=over 4
776
777=item Backends that are autoprobed when no other event loop can be found.
778
779EV is the preferred backend when no other event loop seems to be in
780use. If EV is not installed, then AnyEvent will try Event, and, failing
781that, will fall back to its own pure-perl implementation, which is
782available everywhere as it comes with AnyEvent itself.
783
784 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
785 AnyEvent::Impl::Event based on Event, very stable, few glitches.
786 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
787
788=item Backends that are transparently being picked up when they are used.
789
790These will be used when they are currently loaded when the first watcher
791is created, in which case it is assumed that the application is using
792them. This means that AnyEvent will automatically pick the right backend
793when the main program loads an event module before anything starts to
794create watchers. Nothing special needs to be done by the main program.
795
796 AnyEvent::Impl::Glib based on Glib, slow but very stable.
797 AnyEvent::Impl::Tk based on Tk, very broken.
798 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
799 AnyEvent::Impl::POE based on POE, very slow, some limitations.
800
801=item Backends with special needs.
802
803Qt requires the Qt::Application to be instantiated first, but will
804otherwise be picked up automatically. As long as the main program
805instantiates the application before any AnyEvent watchers are created,
806everything should just work.
807
808 AnyEvent::Impl::Qt based on Qt.
809
810Support for IO::Async can only be partial, as it is too broken and
811architecturally limited to even support the AnyEvent API. It also
812is the only event loop that needs the loop to be set explicitly, so
813it can only be used by a main program knowing about AnyEvent. See
814L<AnyEvent::Impl::Async> for the gory details.
815
816 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
817
818=item Event loops that are indirectly supported via other backends.
819
820Some event loops can be supported via other modules:
821
822There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
823
824B<WxWidgets> has no support for watching file handles. However, you can
825use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
826polls 20 times per second, which was considered to be too horrible to even
827consider for AnyEvent.
828
829B<Prima> is not supported as nobody seems to be using it, but it has a POE
830backend, so it can be supported through POE.
831
832AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
833load L<POE> when detecting them, in the hope that POE will pick them up,
834in which case everything will be automatic.
835
836=back
837
711=head1 GLOBAL VARIABLES AND FUNCTIONS 838=head1 GLOBAL VARIABLES AND FUNCTIONS
712 839
840These are not normally required to use AnyEvent, but can be useful to
841write AnyEvent extension modules.
842
713=over 4 843=over 4
714 844
715=item $AnyEvent::MODEL 845=item $AnyEvent::MODEL
716 846
717Contains C<undef> until the first watcher is being created. Then it 847Contains C<undef> until the first watcher is being created, before the
848backend has been autodetected.
849
718contains the event model that is being used, which is the name of the 850Afterwards it contains the event model that is being used, which is the
719Perl class implementing the model. This class is usually one of the 851name of the Perl class implementing the model. This class is usually one
720C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 852of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
721AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 853case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
722 854will be C<urxvt::anyevent>).
723The known classes so far are:
724
725 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
726 AnyEvent::Impl::Event based on Event, second best choice.
727 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
728 AnyEvent::Impl::Glib based on Glib, third-best choice.
729 AnyEvent::Impl::Tk based on Tk, very bad choice.
730 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
731 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
732 AnyEvent::Impl::POE based on POE, not generic enough for full support.
733
734There is no support for WxWidgets, as WxWidgets has no support for
735watching file handles. However, you can use WxWidgets through the
736POE Adaptor, as POE has a Wx backend that simply polls 20 times per
737second, which was considered to be too horrible to even consider for
738AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
739it's adaptor.
740
741AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
742autodetecting them.
743 855
744=item AnyEvent::detect 856=item AnyEvent::detect
745 857
746Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 858Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
747if necessary. You should only call this function right before you would 859if necessary. You should only call this function right before you would
748have created an AnyEvent watcher anyway, that is, as late as possible at 860have created an AnyEvent watcher anyway, that is, as late as possible at
749runtime. 861runtime, and not e.g. while initialising of your module.
862
863If you need to do some initialisation before AnyEvent watchers are
864created, use C<post_detect>.
750 865
751=item $guard = AnyEvent::post_detect { BLOCK } 866=item $guard = AnyEvent::post_detect { BLOCK }
752 867
753Arranges for the code block to be executed as soon as the event model is 868Arranges for the code block to be executed as soon as the event model is
754autodetected (or immediately if this has already happened). 869autodetected (or immediately if this has already happened).
870
871The block will be executed I<after> the actual backend has been detected
872(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
873created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
874other initialisations - see the sources of L<AnyEvent::Strict> or
875L<AnyEvent::AIO> to see how this is used.
876
877The most common usage is to create some global watchers, without forcing
878event module detection too early, for example, L<AnyEvent::AIO> creates
879and installs the global L<IO::AIO> watcher in a C<post_detect> block to
880avoid autodetecting the event module at load time.
755 881
756If called in scalar or list context, then it creates and returns an object 882If called in scalar or list context, then it creates and returns an object
757that automatically removes the callback again when it is destroyed. See 883that automatically removes the callback again when it is destroyed. See
758L<Coro::BDB> for a case where this is useful. 884L<Coro::BDB> for a case where this is useful.
759 885
762If there are any code references in this array (you can C<push> to it 888If there are any code references in this array (you can C<push> to it
763before or after loading AnyEvent), then they will called directly after 889before or after loading AnyEvent), then they will called directly after
764the event loop has been chosen. 890the event loop has been chosen.
765 891
766You should check C<$AnyEvent::MODEL> before adding to this array, though: 892You should check C<$AnyEvent::MODEL> before adding to this array, though:
767if it contains a true value then the event loop has already been detected, 893if it is defined then the event loop has already been detected, and the
768and the array will be ignored. 894array will be ignored.
769 895
770Best use C<AnyEvent::post_detect { BLOCK }> instead. 896Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
897it,as it takes care of these details.
898
899This variable is mainly useful for modules that can do something useful
900when AnyEvent is used and thus want to know when it is initialised, but do
901not need to even load it by default. This array provides the means to hook
902into AnyEvent passively, without loading it.
771 903
772=back 904=back
773 905
774=head1 WHAT TO DO IN A MODULE 906=head1 WHAT TO DO IN A MODULE
775 907
830 962
831 963
832=head1 OTHER MODULES 964=head1 OTHER MODULES
833 965
834The following is a non-exhaustive list of additional modules that use 966The following is a non-exhaustive list of additional modules that use
835AnyEvent and can therefore be mixed easily with other AnyEvent modules 967AnyEvent as a client and can therefore be mixed easily with other AnyEvent
836in the same program. Some of the modules come with AnyEvent, some are 968modules and other event loops in the same program. Some of the modules
837available via CPAN. 969come with AnyEvent, most are available via CPAN.
838 970
839=over 4 971=over 4
840 972
841=item L<AnyEvent::Util> 973=item L<AnyEvent::Util>
842 974
851 983
852=item L<AnyEvent::Handle> 984=item L<AnyEvent::Handle>
853 985
854Provide read and write buffers, manages watchers for reads and writes, 986Provide read and write buffers, manages watchers for reads and writes,
855supports raw and formatted I/O, I/O queued and fully transparent and 987supports raw and formatted I/O, I/O queued and fully transparent and
856non-blocking SSL/TLS. 988non-blocking SSL/TLS (via L<AnyEvent::TLS>.
857 989
858=item L<AnyEvent::DNS> 990=item L<AnyEvent::DNS>
859 991
860Provides rich asynchronous DNS resolver capabilities. 992Provides rich asynchronous DNS resolver capabilities.
861 993
889 1021
890=item L<AnyEvent::GPSD> 1022=item L<AnyEvent::GPSD>
891 1023
892A non-blocking interface to gpsd, a daemon delivering GPS information. 1024A non-blocking interface to gpsd, a daemon delivering GPS information.
893 1025
1026=item L<AnyEvent::IRC>
1027
1028AnyEvent based IRC client module family (replacing the older Net::IRC3).
1029
1030=item L<AnyEvent::XMPP>
1031
1032AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1033Net::XMPP2>.
1034
894=item L<AnyEvent::IGS> 1035=item L<AnyEvent::IGS>
895 1036
896A non-blocking interface to the Internet Go Server protocol (used by 1037A non-blocking interface to the Internet Go Server protocol (used by
897L<App::IGS>). 1038L<App::IGS>).
898 1039
899=item L<AnyEvent::IRC>
900
901AnyEvent based IRC client module family (replacing the older Net::IRC3).
902
903=item L<Net::XMPP2>
904
905AnyEvent based XMPP (Jabber protocol) module family.
906
907=item L<Net::FCP> 1040=item L<Net::FCP>
908 1041
909AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1042AnyEvent-based implementation of the Freenet Client Protocol, birthplace
910of AnyEvent. 1043of AnyEvent.
911 1044
915 1048
916=item L<Coro> 1049=item L<Coro>
917 1050
918Has special support for AnyEvent via L<Coro::AnyEvent>. 1051Has special support for AnyEvent via L<Coro::AnyEvent>.
919 1052
920=item L<IO::Lambda>
921
922The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
923
924=back 1053=back
925 1054
926=cut 1055=cut
927 1056
928package AnyEvent; 1057package AnyEvent;
929 1058
1059# basically a tuned-down version of common::sense
1060sub common_sense {
930no warnings; 1061 # no warnings
1062 ${^WARNING_BITS} ^= ${^WARNING_BITS};
931use strict qw(vars subs); 1063 # use strict vars subs
1064 $^H |= 0x00000600;
1065}
932 1066
1067BEGIN { AnyEvent::common_sense }
1068
933use Carp; 1069use Carp ();
934 1070
935our $VERSION = 4.41; 1071our $VERSION = 4.85;
936our $MODEL; 1072our $MODEL;
937 1073
938our $AUTOLOAD; 1074our $AUTOLOAD;
939our @ISA; 1075our @ISA;
940 1076
941our @REGISTRY; 1077our @REGISTRY;
942 1078
943our $WIN32; 1079our $WIN32;
944 1080
1081our $VERBOSE;
1082
945BEGIN { 1083BEGIN {
946 my $win32 = ! ! ($^O =~ /mswin32/i); 1084 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
947 eval "sub WIN32(){ $win32 }"; 1085 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
948}
949 1086
1087 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1088 if ${^TAINT};
1089
950our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1090 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1091
1092}
1093
1094our $MAX_SIGNAL_LATENCY = 10;
951 1095
952our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1096our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
953 1097
954{ 1098{
955 my $idx; 1099 my $idx;
963 [Event:: => AnyEvent::Impl::Event::], 1107 [Event:: => AnyEvent::Impl::Event::],
964 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1108 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
965 # everything below here will not be autoprobed 1109 # everything below here will not be autoprobed
966 # as the pureperl backend should work everywhere 1110 # as the pureperl backend should work everywhere
967 # and is usually faster 1111 # and is usually faster
968 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
969 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1112 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
970 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1113 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1114 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
971 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1115 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
972 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1116 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
973 [Wx:: => AnyEvent::Impl::POE::], 1117 [Wx:: => AnyEvent::Impl::POE::],
974 [Prima:: => AnyEvent::Impl::POE::], 1118 [Prima:: => AnyEvent::Impl::POE::],
1119 # IO::Async is just too broken - we would need workarounds for its
1120 # byzantine signal and broken child handling, among others.
1121 # IO::Async is rather hard to detect, as it doesn't have any
1122 # obvious default class.
1123# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1124# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1125# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
975); 1126);
976 1127
977our %method = map +($_ => 1), 1128our %method = map +($_ => 1),
978 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1129 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
979 1130
999 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1150 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1000} 1151}
1001 1152
1002sub detect() { 1153sub detect() {
1003 unless ($MODEL) { 1154 unless ($MODEL) {
1004 no strict 'refs';
1005 local $SIG{__DIE__}; 1155 local $SIG{__DIE__};
1006 1156
1007 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1157 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1008 my $model = "AnyEvent::Impl::$1"; 1158 my $model = "AnyEvent::Impl::$1";
1009 if (eval "require $model") { 1159 if (eval "require $model") {
1010 $MODEL = $model; 1160 $MODEL = $model;
1011 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1161 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1012 } else { 1162 } else {
1013 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1163 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1014 } 1164 }
1015 } 1165 }
1016 1166
1017 # check for already loaded models 1167 # check for already loaded models
1018 unless ($MODEL) { 1168 unless ($MODEL) {
1019 for (@REGISTRY, @models) { 1169 for (@REGISTRY, @models) {
1020 my ($package, $model) = @$_; 1170 my ($package, $model) = @$_;
1021 if (${"$package\::VERSION"} > 0) { 1171 if (${"$package\::VERSION"} > 0) {
1022 if (eval "require $model") { 1172 if (eval "require $model") {
1023 $MODEL = $model; 1173 $MODEL = $model;
1024 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1174 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1025 last; 1175 last;
1026 } 1176 }
1027 } 1177 }
1028 } 1178 }
1029 1179
1034 my ($package, $model) = @$_; 1184 my ($package, $model) = @$_;
1035 if (eval "require $package" 1185 if (eval "require $package"
1036 and ${"$package\::VERSION"} > 0 1186 and ${"$package\::VERSION"} > 0
1037 and eval "require $model") { 1187 and eval "require $model") {
1038 $MODEL = $model; 1188 $MODEL = $model;
1039 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1189 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1040 last; 1190 last;
1041 } 1191 }
1042 } 1192 }
1043 1193
1044 $MODEL 1194 $MODEL
1060 1210
1061sub AUTOLOAD { 1211sub AUTOLOAD {
1062 (my $func = $AUTOLOAD) =~ s/.*://; 1212 (my $func = $AUTOLOAD) =~ s/.*://;
1063 1213
1064 $method{$func} 1214 $method{$func}
1065 or croak "$func: not a valid method for AnyEvent objects"; 1215 or Carp::croak "$func: not a valid method for AnyEvent objects";
1066 1216
1067 detect unless $MODEL; 1217 detect unless $MODEL;
1068 1218
1069 my $class = shift; 1219 my $class = shift;
1070 $class->$func (@_); 1220 $class->$func (@_);
1071} 1221}
1072 1222
1073# utility function to dup a filehandle. this is used by many backends 1223# utility function to dup a filehandle. this is used by many backends
1074# to support binding more than one watcher per filehandle (they usually 1224# to support binding more than one watcher per filehandle (they usually
1075# allow only one watcher per fd, so we dup it to get a different one). 1225# allow only one watcher per fd, so we dup it to get a different one).
1076sub _dupfh($$$$) { 1226sub _dupfh($$;$$) {
1077 my ($poll, $fh, $r, $w) = @_; 1227 my ($poll, $fh, $r, $w) = @_;
1078 1228
1079 # cygwin requires the fh mode to be matching, unix doesn't 1229 # cygwin requires the fh mode to be matching, unix doesn't
1080 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1230 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1081 : $poll eq "w" ? ($w, ">")
1082 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083 1231
1084 open my $fh2, "$mode&" . fileno $fh 1232 open my $fh2, $mode, $fh
1085 or die "cannot dup() filehandle: $!,"; 1233 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1086 1234
1087 # we assume CLOEXEC is already set by perl in all important cases 1235 # we assume CLOEXEC is already set by perl in all important cases
1088 1236
1089 ($fh2, $rw) 1237 ($fh2, $rw)
1090} 1238}
1091 1239
1092package AnyEvent::Base; 1240package AnyEvent::Base;
1093 1241
1094# default implementations for many methods 1242# default implementations for many methods
1095 1243
1096BEGIN { 1244sub _time {
1245 # probe for availability of Time::HiRes
1097 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1246 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1247 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1098 *_time = \&Time::HiRes::time; 1248 *_time = \&Time::HiRes::time;
1099 # if (eval "use POSIX (); (POSIX::times())... 1249 # if (eval "use POSIX (); (POSIX::times())...
1100 } else { 1250 } else {
1251 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1101 *_time = sub { time }; # epic fail 1252 *_time = sub { time }; # epic fail
1102 } 1253 }
1254
1255 &_time
1103} 1256}
1104 1257
1105sub time { _time } 1258sub time { _time }
1106sub now { _time } 1259sub now { _time }
1107sub now_update { } 1260sub now_update { }
1112 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1265 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1113} 1266}
1114 1267
1115# default implementation for ->signal 1268# default implementation for ->signal
1116 1269
1270our $HAVE_ASYNC_INTERRUPT;
1117our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1271our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1272our (%SIG_ASY, %SIG_ASY_W);
1273our ($SIG_COUNT, $SIG_TW);
1118 1274
1119sub _signal_exec { 1275sub _signal_exec {
1276 $HAVE_ASYNC_INTERRUPT
1277 ? $SIGPIPE_R->drain
1120 sysread $SIGPIPE_R, my $dummy, 4; 1278 : sysread $SIGPIPE_R, my $dummy, 9;
1121 1279
1122 while (%SIG_EV) { 1280 while (%SIG_EV) {
1123 for (keys %SIG_EV) { 1281 for (keys %SIG_EV) {
1124 delete $SIG_EV{$_}; 1282 delete $SIG_EV{$_};
1125 $_->() for values %{ $SIG_CB{$_} || {} }; 1283 $_->() for values %{ $SIG_CB{$_} || {} };
1126 } 1284 }
1127 } 1285 }
1128} 1286}
1129 1287
1288# install a dumym wakeupw atcher to reduce signal catching latency
1289sub _sig_add() {
1290 unless ($SIG_COUNT++) {
1291 # try to align timer on a full-second boundary, if possible
1292 my $NOW = AnyEvent->now;
1293
1294 $SIG_TW = AnyEvent->timer (
1295 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1296 interval => $MAX_SIGNAL_LATENCY,
1297 cb => sub { }, # just for the PERL_ASYNC_CHECK
1298 );
1299 }
1300}
1301
1302sub _sig_del {
1303 undef $SIG_TW
1304 unless --$SIG_COUNT;
1305}
1306
1307sub _signal {
1308 my (undef, %arg) = @_;
1309
1310 my $signal = uc $arg{signal}
1311 or Carp::croak "required option 'signal' is missing";
1312
1313 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1314
1315 if ($HAVE_ASYNC_INTERRUPT) {
1316 # async::interrupt
1317
1318 $SIG_ASY{$signal} ||= do {
1319 my $asy = new Async::Interrupt
1320 cb => sub { undef $SIG_EV{$signal} },
1321 signal => $signal,
1322 pipe => [$SIGPIPE_R->filenos],
1323 ;
1324 $asy->pipe_autodrain (0);
1325
1326 $asy
1327 };
1328
1329 } else {
1330 # pure perl
1331
1332 $SIG{$signal} ||= sub {
1333 local $!;
1334 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1335 undef $SIG_EV{$signal};
1336 };
1337
1338 # can't do signal processing without introducing races in pure perl,
1339 # so limit the signal latency.
1340 _sig_add;
1341 }
1342
1343 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1344}
1345
1130sub signal { 1346sub signal {
1131 my (undef, %arg) = @_; 1347 # probe for availability of Async::Interrupt
1348 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1349 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1132 1350
1133 unless ($SIGPIPE_R) { 1351 $HAVE_ASYNC_INTERRUPT = 1;
1352 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1353 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1354
1355 } else {
1356 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1357
1134 require Fcntl; 1358 require Fcntl;
1135 1359
1136 if (AnyEvent::WIN32) { 1360 if (AnyEvent::WIN32) {
1137 require AnyEvent::Util; 1361 require AnyEvent::Util;
1138 1362
1141 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case 1365 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1142 } else { 1366 } else {
1143 pipe $SIGPIPE_R, $SIGPIPE_W; 1367 pipe $SIGPIPE_R, $SIGPIPE_W;
1144 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1368 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1145 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case 1369 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1370
1371 # not strictly required, as $^F is normally 2, but let's make sure...
1372 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1373 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1146 } 1374 }
1147 1375
1148 $SIGPIPE_R 1376 $SIGPIPE_R
1149 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1377 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1150 1378
1151 # not strictly required, as $^F is normally 2, but let's make sure...
1152 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154
1155 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); 1379 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1156 } 1380 }
1157 1381
1158 my $signal = uc $arg{signal} 1382 *signal = \&_signal;
1159 or Carp::croak "required option 'signal' is missing"; 1383 &signal
1160
1161 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1162 $SIG{$signal} ||= sub {
1163 local $!;
1164 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1165 undef $SIG_EV{$signal};
1166 };
1167
1168 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1169} 1384}
1170 1385
1171sub AnyEvent::Base::signal::DESTROY { 1386sub AnyEvent::Base::signal::DESTROY {
1172 my ($signal, $cb) = @{$_[0]}; 1387 my ($signal, $cb) = @{$_[0]};
1173 1388
1389 _sig_del;
1390
1174 delete $SIG_CB{$signal}{$cb}; 1391 delete $SIG_CB{$signal}{$cb};
1175 1392
1176 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; 1393 $HAVE_ASYNC_INTERRUPT
1394 ? delete $SIG_ASY{$signal}
1395 : # delete doesn't work with older perls - they then
1396 # print weird messages, or just unconditionally exit
1397 # instead of getting the default action.
1398 undef $SIG{$signal}
1399 unless keys %{ $SIG_CB{$signal} };
1177} 1400}
1178 1401
1179# default implementation for ->child 1402# default implementation for ->child
1180 1403
1181our %PID_CB; 1404our %PID_CB;
1182our $CHLD_W; 1405our $CHLD_W;
1183our $CHLD_DELAY_W; 1406our $CHLD_DELAY_W;
1184our $PID_IDLE;
1185our $WNOHANG; 1407our $WNOHANG;
1186 1408
1187sub _child_wait { 1409sub _sigchld {
1188 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1410 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1411 $_->($pid, $?)
1189 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1412 for values %{ $PID_CB{$pid} || {} },
1190 (values %{ $PID_CB{0} || {} }); 1413 values %{ $PID_CB{0} || {} };
1191 } 1414 }
1192
1193 undef $PID_IDLE;
1194}
1195
1196sub _sigchld {
1197 # make sure we deliver these changes "synchronous" with the event loop.
1198 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1199 undef $CHLD_DELAY_W;
1200 &_child_wait;
1201 });
1202} 1415}
1203 1416
1204sub child { 1417sub child {
1205 my (undef, %arg) = @_; 1418 my (undef, %arg) = @_;
1206 1419
1207 defined (my $pid = $arg{pid} + 0) 1420 defined (my $pid = $arg{pid} + 0)
1208 or Carp::croak "required option 'pid' is missing"; 1421 or Carp::croak "required option 'pid' is missing";
1209 1422
1210 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1423 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1211 1424
1212 unless ($WNOHANG) { 1425 # WNOHANG is almost cetrainly 1 everywhere
1426 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1427 ? 1
1213 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1428 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1214 }
1215 1429
1216 unless ($CHLD_W) { 1430 unless ($CHLD_W) {
1217 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1431 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1218 # child could be a zombie already, so make at least one round 1432 # child could be a zombie already, so make at least one round
1219 &_sigchld; 1433 &_sigchld;
1230 1444
1231 undef $CHLD_W unless keys %PID_CB; 1445 undef $CHLD_W unless keys %PID_CB;
1232} 1446}
1233 1447
1234# idle emulation is done by simply using a timer, regardless 1448# idle emulation is done by simply using a timer, regardless
1235# of whether the proces sis idle or not, and not letting 1449# of whether the process is idle or not, and not letting
1236# the callback use more than 50% of the time. 1450# the callback use more than 50% of the time.
1237sub idle { 1451sub idle {
1238 my (undef, %arg) = @_; 1452 my (undef, %arg) = @_;
1239 1453
1240 my ($cb, $w, $rcb) = $arg{cb}; 1454 my ($cb, $w, $rcb) = $arg{cb};
1271 1485
1272our @ISA = AnyEvent::CondVar::Base::; 1486our @ISA = AnyEvent::CondVar::Base::;
1273 1487
1274package AnyEvent::CondVar::Base; 1488package AnyEvent::CondVar::Base;
1275 1489
1276use overload 1490#use overload
1277 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1491# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1278 fallback => 1; 1492# fallback => 1;
1493
1494# save 300+ kilobytes by dirtily hardcoding overloading
1495${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1496*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1497*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1498${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1499
1500our $WAITING;
1279 1501
1280sub _send { 1502sub _send {
1281 # nop 1503 # nop
1282} 1504}
1283 1505
1296sub ready { 1518sub ready {
1297 $_[0]{_ae_sent} 1519 $_[0]{_ae_sent}
1298} 1520}
1299 1521
1300sub _wait { 1522sub _wait {
1523 $WAITING
1524 and !$_[0]{_ae_sent}
1525 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1526
1527 local $WAITING = 1;
1301 AnyEvent->one_event while !$_[0]{_ae_sent}; 1528 AnyEvent->one_event while !$_[0]{_ae_sent};
1302} 1529}
1303 1530
1304sub recv { 1531sub recv {
1305 $_[0]->_wait; 1532 $_[0]->_wait;
1346so on. 1573so on.
1347 1574
1348=head1 ENVIRONMENT VARIABLES 1575=head1 ENVIRONMENT VARIABLES
1349 1576
1350The following environment variables are used by this module or its 1577The following environment variables are used by this module or its
1351submodules: 1578submodules.
1579
1580Note that AnyEvent will remove I<all> environment variables starting with
1581C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
1582enabled.
1352 1583
1353=over 4 1584=over 4
1354 1585
1355=item C<PERL_ANYEVENT_VERBOSE> 1586=item C<PERL_ANYEVENT_VERBOSE>
1356 1587
1363C<PERL_ANYEVENT_MODEL>. 1594C<PERL_ANYEVENT_MODEL>.
1364 1595
1365When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1596When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1366model it chooses. 1597model it chooses.
1367 1598
1599When set to C<8> or higher, then AnyEvent will report extra information on
1600which optional modules it loads and how it implements certain features.
1601
1368=item C<PERL_ANYEVENT_STRICT> 1602=item C<PERL_ANYEVENT_STRICT>
1369 1603
1370AnyEvent does not do much argument checking by default, as thorough 1604AnyEvent does not do much argument checking by default, as thorough
1371argument checking is very costly. Setting this variable to a true value 1605argument checking is very costly. Setting this variable to a true value
1372will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1606will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1373check the arguments passed to most method calls. If it finds any problems 1607check the arguments passed to most method calls. If it finds any problems,
1374it will croak. 1608it will croak.
1375 1609
1376In other words, enables "strict" mode. 1610In other words, enables "strict" mode.
1377 1611
1378Unlike C<use strict>, it is definitely recommended ot keep it off in 1612Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1379production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1613>>, it is definitely recommended to keep it off in production. Keeping
1380developing programs can be very useful, however. 1614C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1615can be very useful, however.
1381 1616
1382=item C<PERL_ANYEVENT_MODEL> 1617=item C<PERL_ANYEVENT_MODEL>
1383 1618
1384This can be used to specify the event model to be used by AnyEvent, before 1619This can be used to specify the event model to be used by AnyEvent, before
1385auto detection and -probing kicks in. It must be a string consisting 1620auto detection and -probing kicks in. It must be a string consisting
1428 1663
1429=item C<PERL_ANYEVENT_MAX_FORKS> 1664=item C<PERL_ANYEVENT_MAX_FORKS>
1430 1665
1431The maximum number of child processes that C<AnyEvent::Util::fork_call> 1666The maximum number of child processes that C<AnyEvent::Util::fork_call>
1432will create in parallel. 1667will create in parallel.
1668
1669=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1670
1671The default value for the C<max_outstanding> parameter for the default DNS
1672resolver - this is the maximum number of parallel DNS requests that are
1673sent to the DNS server.
1674
1675=item C<PERL_ANYEVENT_RESOLV_CONF>
1676
1677The file to use instead of F</etc/resolv.conf> (or OS-specific
1678configuration) in the default resolver. When set to the empty string, no
1679default config will be used.
1680
1681=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1682
1683When neither C<ca_file> nor C<ca_path> was specified during
1684L<AnyEvent::TLS> context creation, and either of these environment
1685variables exist, they will be used to specify CA certificate locations
1686instead of a system-dependent default.
1687
1688=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1689
1690When these are set to C<1>, then the respective modules are not
1691loaded. Mostly good for testing AnyEvent itself.
1433 1692
1434=back 1693=back
1435 1694
1436=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1695=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1437 1696
1682 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 1941 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1683 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 1942 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1684 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 1943 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1685 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 1944 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1686 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 1945 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1946 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
1947 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1687 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 1948 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1688 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 1949 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1689 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 1950 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1690 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 1951 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1691 1952
1720performance becomes really bad with lots of file descriptors (and few of 1981performance becomes really bad with lots of file descriptors (and few of
1721them active), of course, but this was not subject of this benchmark. 1982them active), of course, but this was not subject of this benchmark.
1722 1983
1723The C<Event> module has a relatively high setup and callback invocation 1984The C<Event> module has a relatively high setup and callback invocation
1724cost, but overall scores in on the third place. 1985cost, but overall scores in on the third place.
1986
1987C<IO::Async> performs admirably well, about on par with C<Event>, even
1988when using its pure perl backend.
1725 1989
1726C<Glib>'s memory usage is quite a bit higher, but it features a 1990C<Glib>'s memory usage is quite a bit higher, but it features a
1727faster callback invocation and overall ends up in the same class as 1991faster callback invocation and overall ends up in the same class as
1728C<Event>. However, Glib scales extremely badly, doubling the number of 1992C<Event>. However, Glib scales extremely badly, doubling the number of
1729watchers increases the processing time by more than a factor of four, 1993watchers increases the processing time by more than a factor of four,
1807it to another server. This includes deleting the old timeout and creating 2071it to another server. This includes deleting the old timeout and creating
1808a new one that moves the timeout into the future. 2072a new one that moves the timeout into the future.
1809 2073
1810=head3 Results 2074=head3 Results
1811 2075
1812 name sockets create request 2076 name sockets create request
1813 EV 20000 69.01 11.16 2077 EV 20000 69.01 11.16
1814 Perl 20000 73.32 35.87 2078 Perl 20000 73.32 35.87
2079 IOAsync 20000 157.00 98.14 epoll
2080 IOAsync 20000 159.31 616.06 poll
1815 Event 20000 212.62 257.32 2081 Event 20000 212.62 257.32
1816 Glib 20000 651.16 1896.30 2082 Glib 20000 651.16 1896.30
1817 POE 20000 349.67 12317.24 uses POE::Loop::Event 2083 POE 20000 349.67 12317.24 uses POE::Loop::Event
1818 2084
1819=head3 Discussion 2085=head3 Discussion
1820 2086
1821This benchmark I<does> measure scalability and overall performance of the 2087This benchmark I<does> measure scalability and overall performance of the
1822particular event loop. 2088particular event loop.
1824EV is again fastest. Since it is using epoll on my system, the setup time 2090EV is again fastest. Since it is using epoll on my system, the setup time
1825is relatively high, though. 2091is relatively high, though.
1826 2092
1827Perl surprisingly comes second. It is much faster than the C-based event 2093Perl surprisingly comes second. It is much faster than the C-based event
1828loops Event and Glib. 2094loops Event and Glib.
2095
2096IO::Async performs very well when using its epoll backend, and still quite
2097good compared to Glib when using its pure perl backend.
1829 2098
1830Event suffers from high setup time as well (look at its code and you will 2099Event suffers from high setup time as well (look at its code and you will
1831understand why). Callback invocation also has a high overhead compared to 2100understand why). Callback invocation also has a high overhead compared to
1832the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 2101the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1833uses select or poll in basically all documented configurations. 2102uses select or poll in basically all documented configurations.
1896=item * C-based event loops perform very well with small number of 2165=item * C-based event loops perform very well with small number of
1897watchers, as the management overhead dominates. 2166watchers, as the management overhead dominates.
1898 2167
1899=back 2168=back
1900 2169
2170=head2 THE IO::Lambda BENCHMARK
2171
2172Recently I was told about the benchmark in the IO::Lambda manpage, which
2173could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
2174simply compares IO::Lambda with POE, and IO::Lambda looks better (which
2175shouldn't come as a surprise to anybody). As such, the benchmark is
2176fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
2177very optimal. But how would AnyEvent compare when used without the extra
2178baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
2179
2180The benchmark itself creates an echo-server, and then, for 500 times,
2181connects to the echo server, sends a line, waits for the reply, and then
2182creates the next connection. This is a rather bad benchmark, as it doesn't
2183test the efficiency of the framework or much non-blocking I/O, but it is a
2184benchmark nevertheless.
2185
2186 name runtime
2187 Lambda/select 0.330 sec
2188 + optimized 0.122 sec
2189 Lambda/AnyEvent 0.327 sec
2190 + optimized 0.138 sec
2191 Raw sockets/select 0.077 sec
2192 POE/select, components 0.662 sec
2193 POE/select, raw sockets 0.226 sec
2194 POE/select, optimized 0.404 sec
2195
2196 AnyEvent/select/nb 0.085 sec
2197 AnyEvent/EV/nb 0.068 sec
2198 +state machine 0.134 sec
2199
2200The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
2201benchmarks actually make blocking connects and use 100% blocking I/O,
2202defeating the purpose of an event-based solution. All of the newly
2203written AnyEvent benchmarks use 100% non-blocking connects (using
2204AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
2205resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
2206generally require a lot more bookkeeping and event handling than blocking
2207connects (which involve a single syscall only).
2208
2209The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
2210offers similar expressive power as POE and IO::Lambda, using conventional
2211Perl syntax. This means that both the echo server and the client are 100%
2212non-blocking, further placing it at a disadvantage.
2213
2214As you can see, the AnyEvent + EV combination even beats the
2215hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2216backend easily beats IO::Lambda and POE.
2217
2218And even the 100% non-blocking version written using the high-level (and
2219slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
2220large margin, even though it does all of DNS, tcp-connect and socket I/O
2221in a non-blocking way.
2222
2223The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2224F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2225part of the IO::lambda distribution and were used without any changes.
2226
1901 2227
1902=head1 SIGNALS 2228=head1 SIGNALS
1903 2229
1904AnyEvent currently installs handlers for these signals: 2230AnyEvent currently installs handlers for these signals:
1905 2231
1908=item SIGCHLD 2234=item SIGCHLD
1909 2235
1910A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2236A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1911emulation for event loops that do not support them natively. Also, some 2237emulation for event loops that do not support them natively. Also, some
1912event loops install a similar handler. 2238event loops install a similar handler.
2239
2240Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2241AnyEvent will reset it to default, to avoid losing child exit statuses.
1913 2242
1914=item SIGPIPE 2243=item SIGPIPE
1915 2244
1916A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2245A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1917when AnyEvent gets loaded. 2246when AnyEvent gets loaded.
1929 2258
1930=back 2259=back
1931 2260
1932=cut 2261=cut
1933 2262
2263undef $SIG{CHLD}
2264 if $SIG{CHLD} eq 'IGNORE';
2265
1934$SIG{PIPE} = sub { } 2266$SIG{PIPE} = sub { }
1935 unless defined $SIG{PIPE}; 2267 unless defined $SIG{PIPE};
2268
2269=head1 RECOMMENDED/OPTIONAL MODULES
2270
2271One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2272it's built-in modules) are required to use it.
2273
2274That does not mean that AnyEvent won't take advantage of some additional
2275modules if they are installed.
2276
2277This section epxlains which additional modules will be used, and how they
2278affect AnyEvent's operetion.
2279
2280=over 4
2281
2282=item L<Async::Interrupt>
2283
2284This slightly arcane module is used to implement fast signal handling: To
2285my knowledge, there is no way to do completely race-free and quick
2286signal handling in pure perl. To ensure that signals still get
2287delivered, AnyEvent will start an interval timer to wake up perl (and
2288catch the signals) with some delay (default is 10 seconds, look for
2289C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2290
2291If this module is available, then it will be used to implement signal
2292catching, which means that signals will not be delayed, and the event loop
2293will not be interrupted regularly, which is more efficient (And good for
2294battery life on laptops).
2295
2296This affects not just the pure-perl event loop, but also other event loops
2297that have no signal handling on their own (e.g. Glib, Tk, Qt).
2298
2299Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2300and either employ their own workarounds (POE) or use AnyEvent's workaround
2301(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2302does nothing for those backends.
2303
2304=item L<EV>
2305
2306This module isn't really "optional", as it is simply one of the backend
2307event loops that AnyEvent can use. However, it is simply the best event
2308loop available in terms of features, speed and stability: It supports
2309the AnyEvent API optimally, implements all the watcher types in XS, does
2310automatic timer adjustments even when no monotonic clock is available,
2311can take avdantage of advanced kernel interfaces such as C<epoll> and
2312C<kqueue>, and is the fastest backend I<by far>. You can even embed
2313L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2314
2315=item L<Guard>
2316
2317The guard module, when used, will be used to implement
2318C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2319lot less memory), but otherwise doesn't affect guard operation much. It is
2320purely used for performance.
2321
2322=item L<JSON> and L<JSON::XS>
2323
2324This module is required when you want to read or write JSON data via
2325L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2326advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2327
2328In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2329installed.
2330
2331=item L<Net::SSLeay>
2332
2333Implementing TLS/SSL in Perl is certainly interesting, but not very
2334worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2335the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2336
2337=item L<Time::HiRes>
2338
2339This module is part of perl since release 5.008. It will be used when the
2340chosen event library does not come with a timing source on it's own. The
2341pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2342try to use a monotonic clock for timing stability.
2343
2344=back
1936 2345
1937 2346
1938=head1 FORK 2347=head1 FORK
1939 2348
1940Most event libraries are not fork-safe. The ones who are usually are 2349Most event libraries are not fork-safe. The ones who are usually are
1941because they rely on inefficient but fork-safe C<select> or C<poll> 2350because they rely on inefficient but fork-safe C<select> or C<poll>
1942calls. Only L<EV> is fully fork-aware. 2351calls. Only L<EV> is fully fork-aware.
1943 2352
1944If you have to fork, you must either do so I<before> creating your first 2353If you have to fork, you must either do so I<before> creating your first
1945watcher OR you must not use AnyEvent at all in the child. 2354watcher OR you must not use AnyEvent at all in the child OR you must do
2355something completely out of the scope of AnyEvent.
1946 2356
1947 2357
1948=head1 SECURITY CONSIDERATIONS 2358=head1 SECURITY CONSIDERATIONS
1949 2359
1950AnyEvent can be forced to load any event model via 2360AnyEvent can be forced to load any event model via
1962 use AnyEvent; 2372 use AnyEvent;
1963 2373
1964Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2374Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1965be used to probe what backend is used and gain other information (which is 2375be used to probe what backend is used and gain other information (which is
1966probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2376probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1967$ENV{PERL_ANYEGENT_STRICT}. 2377$ENV{PERL_ANYEVENT_STRICT}.
2378
2379Note that AnyEvent will remove I<all> environment variables starting with
2380C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2381enabled.
1968 2382
1969 2383
1970=head1 BUGS 2384=head1 BUGS
1971 2385
1972Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2386Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1984L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2398L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1985 2399
1986Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2400Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1987L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2401L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1988L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2402L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1989L<AnyEvent::Impl::POE>. 2403L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1990 2404
1991Non-blocking file handles, sockets, TCP clients and 2405Non-blocking file handles, sockets, TCP clients and
1992servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2406servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1993 2407
1994Asynchronous DNS: L<AnyEvent::DNS>. 2408Asynchronous DNS: L<AnyEvent::DNS>.
1995 2409
1996Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2410Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2411L<Coro::Event>,
1997 2412
1998Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2413Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2414L<AnyEvent::HTTP>.
1999 2415
2000 2416
2001=head1 AUTHOR 2417=head1 AUTHOR
2002 2418
2003 Marc Lehmann <schmorp@schmorp.de> 2419 Marc Lehmann <schmorp@schmorp.de>

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