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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?
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
403 429
404This means you cannot create a child watcher as the very first 430This means you cannot create a child watcher as the very first
405thing in an AnyEvent program, you I<have> to create at least one 431thing in an AnyEvent program, you I<have> to create at least one
406watcher before you C<fork> the child (alternatively, you can call 432watcher before you C<fork> the child (alternatively, you can call
407C<AnyEvent::detect>). 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.
408 438
409Example: fork a process and wait for it 439Example: fork a process and wait for it
410 440
411 my $done = AnyEvent->condvar; 441 my $done = AnyEvent->condvar;
412 442
463 493
464If 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
465require you to run some blocking "loop", "run" or similar function that 495require you to run some blocking "loop", "run" or similar function that
466will actively watch for new events and call your callbacks. 496will actively watch for new events and call your callbacks.
467 497
468AnyEvent is different, it expects somebody else to run the event loop and 498AnyEvent is slightly different: it expects somebody else to run the event
469will only block when necessary (usually when told by the user). 499loop and will only block when necessary (usually when told by the user).
470 500
471The instrument to do that is called a "condition variable", so called 501The instrument to do that is called a "condition variable", so called
472because they represent a condition that must become true. 502because they represent a condition that must become true.
473 503
504Now is probably a good time to look at the examples further below.
505
474Condition variables can be created by calling the C<< AnyEvent->condvar 506Condition variables can be created by calling the C<< AnyEvent->condvar
475>> method, usually without arguments. The only argument pair allowed is 507>> method, usually without arguments. The only argument pair allowed is
476
477C<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
478becomes true, with the condition variable as the first argument (but not 509becomes true, with the condition variable as the first argument (but not
479the results). 510the results).
480 511
481After creation, the condition variable is "false" until it becomes "true" 512After creation, the condition variable is "false" until it becomes "true"
486Condition variables are similar to callbacks, except that you can 517Condition variables are similar to callbacks, except that you can
487optionally wait for them. They can also be called merge points - points 518optionally wait for them. They can also be called merge points - points
488in time where multiple outstanding events have been processed. And yet 519in time where multiple outstanding events have been processed. And yet
489another way to call them is transactions - each condition variable can be 520another way to call them is transactions - each condition variable can be
490used to represent a transaction, which finishes at some point and delivers 521used to represent a transaction, which finishes at some point and delivers
491a result. 522a result. And yet some people know them as "futures" - a promise to
523compute/deliver something that you can wait for.
492 524
493Condition variables are very useful to signal that something has finished, 525Condition variables are very useful to signal that something has finished,
494for example, if you write a module that does asynchronous http requests, 526for example, if you write a module that does asynchronous http requests,
495then a condition variable would be the ideal candidate to signal the 527then a condition variable would be the ideal candidate to signal the
496availability of results. The user can either act when the callback is 528availability of results. The user can either act when the callback is
530 after => 1, 562 after => 1,
531 cb => sub { $result_ready->send }, 563 cb => sub { $result_ready->send },
532 ); 564 );
533 565
534 # this "blocks" (while handling events) till the callback 566 # this "blocks" (while handling events) till the callback
535 # calls send 567 # calls -<send
536 $result_ready->recv; 568 $result_ready->recv;
537 569
538Example: wait for a timer, but take advantage of the fact that 570Example: wait for a timer, but take advantage of the fact that condition
539condition variables are also code references. 571variables are also callable directly.
540 572
541 my $done = AnyEvent->condvar; 573 my $done = AnyEvent->condvar;
542 my $delay = AnyEvent->timer (after => 5, cb => $done); 574 my $delay = AnyEvent->timer (after => 5, cb => $done);
543 $done->recv; 575 $done->recv;
544 576
550 582
551 ... 583 ...
552 584
553 my @info = $couchdb->info->recv; 585 my @info = $couchdb->info->recv;
554 586
555And 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
556results are available: 588results are available:
557 589
558 $couchdb->info->cb (sub { 590 $couchdb->info->cb (sub {
559 my @info = $_[0]->recv; 591 my @info = $_[0]->recv;
560 }); 592 });
578immediately from within send. 610immediately from within send.
579 611
580Any 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
581future C<< ->recv >> calls. 613future C<< ->recv >> calls.
582 614
583Condition variables are overloaded so one can call them directly 615Condition variables are overloaded so one can call them directly (as if
584(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
585C<send>. Note, however, that many C-based event loops do not handle 617C<send>.
586overloading, so as tempting as it may be, passing a condition variable
587instead of a callback does not work. Both the pure perl and EV loops
588support overloading, however, as well as all functions that use perl to
589invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590example).
591 618
592=item $cv->croak ($error) 619=item $cv->croak ($error)
593 620
594Similar 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
595C<Carp::croak> with the given error message/object/scalar. 622C<Carp::croak> with the given error message/object/scalar.
596 623
597This can be used to signal any errors to the condition variable 624This can be used to signal any errors to the condition variable
598user/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.
599 630
600=item $cv->begin ([group callback]) 631=item $cv->begin ([group callback])
601 632
602=item $cv->end 633=item $cv->end
603 634
699function will call C<croak>. 730function will call C<croak>.
700 731
701In list context, all parameters passed to C<send> will be returned, 732In list context, all parameters passed to C<send> will be returned,
702in scalar context only the first one will be returned. 733in scalar context only the first one will be returned.
703 734
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
704Not 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
705(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
706using 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
707caller 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
708condition variables with some kind of request results and supporting 746condition variables with some kind of request results and supporting
709callbacks so the caller knows that getting the result will not block, 747callbacks so the caller knows that getting the result will not block,
710while still supporting blocking waits if the caller so desires). 748while still supporting blocking waits if the caller so desires).
711 749
712Another reason I<never> to C<< ->recv >> in a module is that you cannot
713sensibly have two C<< ->recv >>'s in parallel, as that would require
714multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715can supply.
716
717The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719versions and also integrates coroutines into AnyEvent, making blocking
720C<< ->recv >> calls perfectly safe as long as they are done from another
721coroutine (one that doesn't run the event loop).
722
723You 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
724only calling C<< ->recv >> from within that callback (or at a later 751only calling C<< ->recv >> from within that callback (or at a later
725time). 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
726waits otherwise. 753waits otherwise.
727 754
740variable 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
741is guaranteed not to block. 768is guaranteed not to block.
742 769
743=back 770=back
744 771
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
745=head1 GLOBAL VARIABLES AND FUNCTIONS 839=head1 GLOBAL VARIABLES AND FUNCTIONS
746 840
841These are not normally required to use AnyEvent, but can be useful to
842write AnyEvent extension modules.
843
747=over 4 844=over 4
748 845
749=item $AnyEvent::MODEL 846=item $AnyEvent::MODEL
750 847
751Contains 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
752contains 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
753Perl class implementing the model. This class is usually one of the 852name of the Perl class implementing the model. This class is usually one
754C<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
755AnyEvent 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
756 855will be C<urxvt::anyevent>).
757The known classes so far are:
758
759 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760 AnyEvent::Impl::Event based on Event, second best choice.
761 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762 AnyEvent::Impl::Glib based on Glib, third-best choice.
763 AnyEvent::Impl::Tk based on Tk, very bad choice.
764 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766 AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768 # warning, support for IO::Async is only partial, as it is too broken
769 # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772There is no support for WxWidgets, as WxWidgets has no support for
773watching file handles. However, you can use WxWidgets through the
774POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775second, which was considered to be too horrible to even consider for
776AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777it's adaptor.
778
779AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780autodetecting them.
781 856
782=item AnyEvent::detect 857=item AnyEvent::detect
783 858
784Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 859Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785if necessary. You should only call this function right before you would 860if necessary. You should only call this function right before you would
786have 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
787runtime. 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>.
788 866
789=item $guard = AnyEvent::post_detect { BLOCK } 867=item $guard = AnyEvent::post_detect { BLOCK }
790 868
791Arranges for the code block to be executed as soon as the event model is 869Arranges for the code block to be executed as soon as the event model is
792autodetected (or immediately if this has already happened). 870autodetected (or immediately if this has already happened).
793 871
872The block will be executed I<after> the actual backend has been detected
873(C<$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
794If 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
795that 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
796L<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 ||= $guard;
797 903
798=item @AnyEvent::post_detect 904=item @AnyEvent::post_detect
799 905
800If there are any code references in this array (you can C<push> to it 906If there are any code references in this array (you can C<push> to it
801before or after loading AnyEvent), then they will called directly after 907before or after loading AnyEvent), then they will called directly after
802the event loop has been chosen. 908the event loop has been chosen.
803 909
804You should check C<$AnyEvent::MODEL> before adding to this array, though: 910You should check C<$AnyEvent::MODEL> before adding to this array, though:
805if 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
806and the array will be ignored. 912array will be ignored.
807 913
808Best 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.
809 921
810=back 922=back
811 923
812=head1 WHAT TO DO IN A MODULE 924=head1 WHAT TO DO IN A MODULE
813 925
868 980
869 981
870=head1 OTHER MODULES 982=head1 OTHER MODULES
871 983
872The following is a non-exhaustive list of additional modules that use 984The following is a non-exhaustive list of additional modules that use
873AnyEvent and can therefore be mixed easily with other AnyEvent modules 985AnyEvent as a client and can therefore be mixed easily with other AnyEvent
874in 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
875available via CPAN. 987come with AnyEvent, most are available via CPAN.
876 988
877=over 4 989=over 4
878 990
879=item L<AnyEvent::Util> 991=item L<AnyEvent::Util>
880 992
889 1001
890=item L<AnyEvent::Handle> 1002=item L<AnyEvent::Handle>
891 1003
892Provide read and write buffers, manages watchers for reads and writes, 1004Provide read and write buffers, manages watchers for reads and writes,
893supports 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
894non-blocking SSL/TLS. 1006non-blocking SSL/TLS (via L<AnyEvent::TLS>.
895 1007
896=item L<AnyEvent::DNS> 1008=item L<AnyEvent::DNS>
897 1009
898Provides rich asynchronous DNS resolver capabilities. 1010Provides rich asynchronous DNS resolver capabilities.
899 1011
927 1039
928=item L<AnyEvent::GPSD> 1040=item L<AnyEvent::GPSD>
929 1041
930A non-blocking interface to gpsd, a daemon delivering GPS information. 1042A non-blocking interface to gpsd, a daemon delivering GPS information.
931 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
932=item L<AnyEvent::IGS> 1053=item L<AnyEvent::IGS>
933 1054
934A non-blocking interface to the Internet Go Server protocol (used by 1055A non-blocking interface to the Internet Go Server protocol (used by
935L<App::IGS>). 1056L<App::IGS>).
936 1057
937=item L<AnyEvent::IRC>
938
939AnyEvent based IRC client module family (replacing the older Net::IRC3).
940
941=item L<Net::XMPP2>
942
943AnyEvent based XMPP (Jabber protocol) module family.
944
945=item L<Net::FCP> 1058=item L<Net::FCP>
946 1059
947AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1060AnyEvent-based implementation of the Freenet Client Protocol, birthplace
948of AnyEvent. 1061of AnyEvent.
949 1062
953 1066
954=item L<Coro> 1067=item L<Coro>
955 1068
956Has special support for AnyEvent via L<Coro::AnyEvent>. 1069Has special support for AnyEvent via L<Coro::AnyEvent>.
957 1070
958=item L<IO::Lambda>
959
960The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
961
962=back 1071=back
963 1072
964=cut 1073=cut
965 1074
966package AnyEvent; 1075package AnyEvent;
967 1076
1077# basically a tuned-down version of common::sense
1078sub common_sense {
968no warnings; 1079 # no warnings
1080 ${^WARNING_BITS} ^= ${^WARNING_BITS};
969use strict qw(vars subs); 1081 # use strict vars subs
1082 $^H |= 0x00000600;
1083}
970 1084
1085BEGIN { AnyEvent::common_sense }
1086
971use Carp; 1087use Carp ();
972 1088
973our $VERSION = 4.8; 1089our $VERSION = 4.86;
974our $MODEL; 1090our $MODEL;
975 1091
976our $AUTOLOAD; 1092our $AUTOLOAD;
977our @ISA; 1093our @ISA;
978 1094
979our @REGISTRY; 1095our @REGISTRY;
980 1096
981our $WIN32; 1097our $WIN32;
1098
1099our $VERBOSE;
982 1100
983BEGIN { 1101BEGIN {
984 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1102 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
985 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1103 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
986 1104
987 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1105 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
988 if ${^TAINT}; 1106 if ${^TAINT};
989}
990 1107
991our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1108 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1109
1110}
1111
1112our $MAX_SIGNAL_LATENCY = 10;
992 1113
993our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1114our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
994 1115
995{ 1116{
996 my $idx; 1117 my $idx;
1004 [Event:: => AnyEvent::Impl::Event::], 1125 [Event:: => AnyEvent::Impl::Event::],
1005 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1126 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1006 # everything below here will not be autoprobed 1127 # everything below here will not be autoprobed
1007 # as the pureperl backend should work everywhere 1128 # as the pureperl backend should work everywhere
1008 # and is usually faster 1129 # and is usually faster
1009 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1010 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1130 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1011 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1131 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1132 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1012 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1133 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1013 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1134 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1014 [Wx:: => AnyEvent::Impl::POE::], 1135 [Wx:: => AnyEvent::Impl::POE::],
1015 [Prima:: => AnyEvent::Impl::POE::], 1136 [Prima:: => AnyEvent::Impl::POE::],
1016 # IO::Async is just too broken - we would need workaorunds for its 1137 # IO::Async is just too broken - we would need workarounds for its
1017 # byzantine signal and broken child handling, among others. 1138 # byzantine signal and broken child handling, among others.
1018 # IO::Async is rather hard to detect, as it doesn't have any 1139 # IO::Async is rather hard to detect, as it doesn't have any
1019 # obvious default class. 1140 # obvious default class.
1020# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1141# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1021# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1142# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1031 my ($cb) = @_; 1152 my ($cb) = @_;
1032 1153
1033 if ($MODEL) { 1154 if ($MODEL) {
1034 $cb->(); 1155 $cb->();
1035 1156
1036 1 1157 undef
1037 } else { 1158 } else {
1038 push @post_detect, $cb; 1159 push @post_detect, $cb;
1039 1160
1040 defined wantarray 1161 defined wantarray
1041 ? bless \$cb, "AnyEvent::Util::postdetect" 1162 ? bless \$cb, "AnyEvent::Util::postdetect"
1047 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1168 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1048} 1169}
1049 1170
1050sub detect() { 1171sub detect() {
1051 unless ($MODEL) { 1172 unless ($MODEL) {
1052 no strict 'refs';
1053 local $SIG{__DIE__}; 1173 local $SIG{__DIE__};
1054 1174
1055 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1175 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1056 my $model = "AnyEvent::Impl::$1"; 1176 my $model = "AnyEvent::Impl::$1";
1057 if (eval "require $model") { 1177 if (eval "require $model") {
1058 $MODEL = $model; 1178 $MODEL = $model;
1059 warn "AnyEvent: loaded model '$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 $VERBOSE >= 2;
1060 } else { 1180 } else {
1061 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1181 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1062 } 1182 }
1063 } 1183 }
1064 1184
1065 # check for already loaded models 1185 # check for already loaded models
1066 unless ($MODEL) { 1186 unless ($MODEL) {
1067 for (@REGISTRY, @models) { 1187 for (@REGISTRY, @models) {
1068 my ($package, $model) = @$_; 1188 my ($package, $model) = @$_;
1069 if (${"$package\::VERSION"} > 0) { 1189 if (${"$package\::VERSION"} > 0) {
1070 if (eval "require $model") { 1190 if (eval "require $model") {
1071 $MODEL = $model; 1191 $MODEL = $model;
1072 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1192 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1073 last; 1193 last;
1074 } 1194 }
1075 } 1195 }
1076 } 1196 }
1077 1197
1082 my ($package, $model) = @$_; 1202 my ($package, $model) = @$_;
1083 if (eval "require $package" 1203 if (eval "require $package"
1084 and ${"$package\::VERSION"} > 0 1204 and ${"$package\::VERSION"} > 0
1085 and eval "require $model") { 1205 and eval "require $model") {
1086 $MODEL = $model; 1206 $MODEL = $model;
1087 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1207 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1088 last; 1208 last;
1089 } 1209 }
1090 } 1210 }
1091 1211
1092 $MODEL 1212 $MODEL
1108 1228
1109sub AUTOLOAD { 1229sub AUTOLOAD {
1110 (my $func = $AUTOLOAD) =~ s/.*://; 1230 (my $func = $AUTOLOAD) =~ s/.*://;
1111 1231
1112 $method{$func} 1232 $method{$func}
1113 or croak "$func: not a valid method for AnyEvent objects"; 1233 or Carp::croak "$func: not a valid method for AnyEvent objects";
1114 1234
1115 detect unless $MODEL; 1235 detect unless $MODEL;
1116 1236
1117 my $class = shift; 1237 my $class = shift;
1118 $class->$func (@_); 1238 $class->$func (@_);
1123# 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).
1124sub _dupfh($$;$$) { 1244sub _dupfh($$;$$) {
1125 my ($poll, $fh, $r, $w) = @_; 1245 my ($poll, $fh, $r, $w) = @_;
1126 1246
1127 # cygwin requires the fh mode to be matching, unix doesn't 1247 # cygwin requires the fh mode to be matching, unix doesn't
1128 my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">"); 1248 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1129 1249
1130 open my $fh2, "$mode&", $fh 1250 open my $fh2, $mode, $fh
1131 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,"; 1251 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1132 1252
1133 # we assume CLOEXEC is already set by perl in all important cases 1253 # we assume CLOEXEC is already set by perl in all important cases
1134 1254
1135 ($fh2, $rw) 1255 ($fh2, $rw)
1137 1257
1138package AnyEvent::Base; 1258package AnyEvent::Base;
1139 1259
1140# default implementations for many methods 1260# default implementations for many methods
1141 1261
1142BEGIN { 1262sub _time {
1263 # probe for availability of Time::HiRes
1143 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;
1144 *_time = \&Time::HiRes::time; 1266 *_time = \&Time::HiRes::time;
1145 # if (eval "use POSIX (); (POSIX::times())... 1267 # if (eval "use POSIX (); (POSIX::times())...
1146 } else { 1268 } else {
1269 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1147 *_time = sub { time }; # epic fail 1270 *_time = sub { time }; # epic fail
1148 } 1271 }
1272
1273 &_time
1149} 1274}
1150 1275
1151sub time { _time } 1276sub time { _time }
1152sub now { _time } 1277sub now { _time }
1153sub now_update { } 1278sub now_update { }
1158 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1283 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1159} 1284}
1160 1285
1161# default implementation for ->signal 1286# default implementation for ->signal
1162 1287
1288our $HAVE_ASYNC_INTERRUPT;
1163our ($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);
1164 1292
1165sub _signal_exec { 1293sub _signal_exec {
1294 $HAVE_ASYNC_INTERRUPT
1295 ? $SIGPIPE_R->drain
1166 sysread $SIGPIPE_R, my $dummy, 4; 1296 : sysread $SIGPIPE_R, my $dummy, 9;
1167 1297
1168 while (%SIG_EV) { 1298 while (%SIG_EV) {
1169 for (keys %SIG_EV) { 1299 for (keys %SIG_EV) {
1170 delete $SIG_EV{$_}; 1300 delete $SIG_EV{$_};
1171 $_->() for values %{ $SIG_CB{$_} || {} }; 1301 $_->() for values %{ $SIG_CB{$_} || {} };
1172 } 1302 }
1173 } 1303 }
1174} 1304}
1175 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, $arg{cb}], "AnyEvent::Base::signal"
1362}
1363
1176sub signal { 1364sub signal {
1177 my (undef, %arg) = @_; 1365 # probe for availability of Async::Interrupt
1366 if (!$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 $VERBOSE >= 8;
1178 1368
1179 unless ($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
1180 require Fcntl; 1376 require Fcntl;
1181 1377
1182 if (AnyEvent::WIN32) { 1378 if (AnyEvent::WIN32) {
1183 require AnyEvent::Util; 1379 require AnyEvent::Util;
1184 1380
1199 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";
1200 1396
1201 $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);
1202 } 1398 }
1203 1399
1204 my $signal = uc $arg{signal} 1400 *signal = \&_signal;
1205 or Carp::croak "required option 'signal' is missing"; 1401 &signal
1206
1207 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1208 $SIG{$signal} ||= sub {
1209 local $!;
1210 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1211 undef $SIG_EV{$signal};
1212 };
1213
1214 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1215} 1402}
1216 1403
1217sub AnyEvent::Base::signal::DESTROY { 1404sub AnyEvent::Base::signal::DESTROY {
1218 my ($signal, $cb) = @{$_[0]}; 1405 my ($signal, $cb) = @{$_[0]};
1219 1406
1407 _sig_del;
1408
1220 delete $SIG_CB{$signal}{$cb}; 1409 delete $SIG_CB{$signal}{$cb};
1221 1410
1411 $HAVE_ASYNC_INTERRUPT
1412 ? delete $SIG_ASY{$signal}
1222 # delete doesn't work with older perls - they then 1413 : # delete doesn't work with older perls - they then
1223 # print weird messages, or just unconditionally exit 1414 # print weird messages, or just unconditionally exit
1224 # instead of getting the default action. 1415 # instead of getting the default action.
1416 undef $SIG{$signal}
1225 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1417 unless keys %{ $SIG_CB{$signal} };
1226} 1418}
1227 1419
1228# default implementation for ->child 1420# default implementation for ->child
1229 1421
1230our %PID_CB; 1422our %PID_CB;
1232our $CHLD_DELAY_W; 1424our $CHLD_DELAY_W;
1233our $WNOHANG; 1425our $WNOHANG;
1234 1426
1235sub _sigchld { 1427sub _sigchld {
1236 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1428 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1429 $_->($pid, $?)
1237 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1430 for values %{ $PID_CB{$pid} || {} },
1238 (values %{ $PID_CB{0} || {} }); 1431 values %{ $PID_CB{0} || {} };
1239 } 1432 }
1240} 1433}
1241 1434
1242sub child { 1435sub child {
1243 my (undef, %arg) = @_; 1436 my (undef, %arg) = @_;
1245 defined (my $pid = $arg{pid} + 0) 1438 defined (my $pid = $arg{pid} + 0)
1246 or Carp::croak "required option 'pid' is missing"; 1439 or Carp::croak "required option 'pid' is missing";
1247 1440
1248 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1441 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1249 1442
1443 # WNOHANG is almost cetrainly 1 everywhere
1444 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1445 ? 1
1250 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1446 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1251 1447
1252 unless ($CHLD_W) { 1448 unless ($CHLD_W) {
1253 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1449 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1254 # 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
1255 &_sigchld; 1451 &_sigchld;
1307 1503
1308our @ISA = AnyEvent::CondVar::Base::; 1504our @ISA = AnyEvent::CondVar::Base::;
1309 1505
1310package AnyEvent::CondVar::Base; 1506package AnyEvent::CondVar::Base;
1311 1507
1312use overload 1508#use overload
1313 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1509# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1314 fallback => 1; 1510# fallback => 1;
1511
1512# save 300+ kilobytes by dirtily hardcoding overloading
1513${"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;
1315 1519
1316sub _send { 1520sub _send {
1317 # nop 1521 # nop
1318} 1522}
1319 1523
1332sub ready { 1536sub ready {
1333 $_[0]{_ae_sent} 1537 $_[0]{_ae_sent}
1334} 1538}
1335 1539
1336sub _wait { 1540sub _wait {
1541 $WAITING
1542 and !$_[0]{_ae_sent}
1543 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1544
1545 local $WAITING = 1;
1337 AnyEvent->one_event while !$_[0]{_ae_sent}; 1546 AnyEvent->one_event while !$_[0]{_ae_sent};
1338} 1547}
1339 1548
1340sub recv { 1549sub recv {
1341 $_[0]->_wait; 1550 $_[0]->_wait;
1403C<PERL_ANYEVENT_MODEL>. 1612C<PERL_ANYEVENT_MODEL>.
1404 1613
1405When 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
1406model it chooses. 1615model it chooses.
1407 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
1408=item C<PERL_ANYEVENT_STRICT> 1620=item C<PERL_ANYEVENT_STRICT>
1409 1621
1410AnyEvent does not do much argument checking by default, as thorough 1622AnyEvent does not do much argument checking by default, as thorough
1411argument checking is very costly. Setting this variable to a true value 1623argument checking is very costly. Setting this variable to a true value
1412will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1624will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1413check 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,
1414it will croak. 1626it will croak.
1415 1627
1416In other words, enables "strict" mode. 1628In other words, enables "strict" mode.
1417 1629
1418Unlike C<use strict>, it is definitely recommended to keep it off in 1630Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1419production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1631>>, it is definitely recommended to keep it off in production. Keeping
1420developing programs can be very useful, however. 1632C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1633can be very useful, however.
1421 1634
1422=item C<PERL_ANYEVENT_MODEL> 1635=item C<PERL_ANYEVENT_MODEL>
1423 1636
1424This 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
1425auto detection and -probing kicks in. It must be a string consisting 1638auto detection and -probing kicks in. It must be a string consisting
1487 1700
1488When neither C<ca_file> nor C<ca_path> was specified during 1701When neither C<ca_file> nor C<ca_path> was specified during
1489L<AnyEvent::TLS> context creation, and either of these environment 1702L<AnyEvent::TLS> context creation, and either of these environment
1490variables exist, they will be used to specify CA certificate locations 1703variables exist, they will be used to specify CA certificate locations
1491instead of a system-dependent default. 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.
1492 1710
1493=back 1711=back
1494 1712
1495=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1713=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1496 1714
2035 2253
2036A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2254A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2037emulation for event loops that do not support them natively. Also, some 2255emulation for event loops that do not support them natively. Also, some
2038event loops install a similar handler. 2256event loops install a similar handler.
2039 2257
2040If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will 2258Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2041reset it to default, to avoid losing child exit statuses. 2259AnyEvent will reset it to default, to avoid losing child exit statuses.
2042 2260
2043=item SIGPIPE 2261=item SIGPIPE
2044 2262
2045A 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>
2046when AnyEvent gets loaded. 2264when AnyEvent gets loaded.
2064 if $SIG{CHLD} eq 'IGNORE'; 2282 if $SIG{CHLD} eq 'IGNORE';
2065 2283
2066$SIG{PIPE} = sub { } 2284$SIG{PIPE} = sub { }
2067 unless defined $SIG{PIPE}; 2285 unless defined $SIG{PIPE};
2068 2286
2287=head1 RECOMMENDED/OPTIONAL MODULES
2288
2289One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2290it's built-in modules) are required to use it.
2291
2292That does not mean that AnyEvent won't take advantage of some additional
2293modules if they are installed.
2294
2295This section epxlains which additional modules will be used, and how they
2296affect AnyEvent's operetion.
2297
2298=over 4
2299
2300=item L<Async::Interrupt>
2301
2302This slightly arcane module is used to implement fast signal handling: To
2303my knowledge, there is no way to do completely race-free and quick
2304signal handling in pure perl. To ensure that signals still get
2305delivered, AnyEvent will start an interval timer to wake up perl (and
2306catch the signals) with some delay (default is 10 seconds, look for
2307C<$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
2363
2364
2069=head1 FORK 2365=head1 FORK
2070 2366
2071Most 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
2072because 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>
2073calls. Only L<EV> is fully fork-aware. 2369calls. Only L<EV> is fully fork-aware.
2074 2370
2075If 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
2076watcher 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.
2077 2374
2078 2375
2079=head1 SECURITY CONSIDERATIONS 2376=head1 SECURITY CONSIDERATIONS
2080 2377
2081AnyEvent can be forced to load any event model via 2378AnyEvent can be forced to load any event model via
2119L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2416L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2120 2417
2121Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2418Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2122L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2419L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2123L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2420L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2124L<AnyEvent::Impl::POE>. 2421L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
2125 2422
2126Non-blocking file handles, sockets, TCP clients and 2423Non-blocking file handles, sockets, TCP clients and
2127servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2424servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2128 2425
2129Asynchronous DNS: L<AnyEvent::DNS>. 2426Asynchronous DNS: L<AnyEvent::DNS>.
2130 2427
2131Coroutine 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>,
2132 2430
2133Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2431Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2432L<AnyEvent::HTTP>.
2134 2433
2135 2434
2136=head1 AUTHOR 2435=head1 AUTHOR
2137 2436
2138 Marc Lehmann <schmorp@schmorp.de> 2437 Marc Lehmann <schmorp@schmorp.de>

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