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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"
530 after => 1, 561 after => 1,
531 cb => sub { $result_ready->send }, 562 cb => sub { $result_ready->send },
532 ); 563 );
533 564
534 # this "blocks" (while handling events) till the callback 565 # this "blocks" (while handling events) till the callback
535 # calls send 566 # calls -<send
536 $result_ready->recv; 567 $result_ready->recv;
537 568
538Example: wait for a timer, but take advantage of the fact that 569Example: wait for a timer, but take advantage of the fact that condition
539condition variables are also code references. 570variables are also callable directly.
540 571
541 my $done = AnyEvent->condvar; 572 my $done = AnyEvent->condvar;
542 my $delay = AnyEvent->timer (after => 5, cb => $done); 573 my $delay = AnyEvent->timer (after => 5, cb => $done);
543 $done->recv; 574 $done->recv;
544 575
550 581
551 ... 582 ...
552 583
553 my @info = $couchdb->info->recv; 584 my @info = $couchdb->info->recv;
554 585
555And 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
556results are available: 587results are available:
557 588
558 $couchdb->info->cb (sub { 589 $couchdb->info->cb (sub {
559 my @info = $_[0]->recv; 590 my @info = $_[0]->recv;
560 }); 591 });
578immediately from within send. 609immediately from within send.
579 610
580Any 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
581future C<< ->recv >> calls. 612future C<< ->recv >> calls.
582 613
583Condition variables are overloaded so one can call them directly 614Condition variables are overloaded so one can call them directly (as if
584(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
585C<send>. Note, however, that many C-based event loops do not handle 616C<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).
591 617
592=item $cv->croak ($error) 618=item $cv->croak ($error)
593 619
594Similar 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
595C<Carp::croak> with the given error message/object/scalar. 621C<Carp::croak> with the given error message/object/scalar.
596 622
597This can be used to signal any errors to the condition variable 623This can be used to signal any errors to the condition variable
598user/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.
599 629
600=item $cv->begin ([group callback]) 630=item $cv->begin ([group callback])
601 631
602=item $cv->end 632=item $cv->end
603 633
699function will call C<croak>. 729function will call C<croak>.
700 730
701In list context, all parameters passed to C<send> will be returned, 731In list context, all parameters passed to C<send> will be returned,
702in scalar context only the first one will be returned. 732in scalar context only the first one will be returned.
703 733
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
704Not 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
705(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
706using 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
707caller 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
708condition variables with some kind of request results and supporting 745condition variables with some kind of request results and supporting
709callbacks so the caller knows that getting the result will not block, 746callbacks so the caller knows that getting the result will not block,
710while still supporting blocking waits if the caller so desires). 747while still supporting blocking waits if the caller so desires).
711 748
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 749You can ensure that C<< -recv >> never blocks by setting a callback and
724only calling C<< ->recv >> from within that callback (or at a later 750only calling C<< ->recv >> from within that callback (or at a later
725time). 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
726waits otherwise. 752waits otherwise.
727 753
740variable 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
741is guaranteed not to block. 767is guaranteed not to block.
742 768
743=back 769=back
744 770
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
745=head1 GLOBAL VARIABLES AND FUNCTIONS 838=head1 GLOBAL VARIABLES AND FUNCTIONS
746 839
840These are not normally required to use AnyEvent, but can be useful to
841write AnyEvent extension modules.
842
747=over 4 843=over 4
748 844
749=item $AnyEvent::MODEL 845=item $AnyEvent::MODEL
750 846
751Contains 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
752contains 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
753Perl class implementing the model. This class is usually one of the 851name 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 852of 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>). 853case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756 854will 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.
781 855
782=item AnyEvent::detect 856=item AnyEvent::detect
783 857
784Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 858Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785if necessary. You should only call this function right before you would 859if necessary. You should only call this function right before you would
786have 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
787runtime. 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>.
788 865
789=item $guard = AnyEvent::post_detect { BLOCK } 866=item $guard = AnyEvent::post_detect { BLOCK }
790 867
791Arranges for the code block to be executed as soon as the event model is 868Arranges for the code block to be executed as soon as the event model is
792autodetected (or immediately if this has already happened). 869autodetected (or immediately if this has already happened).
870
871The block will be executed I<after> the actual backend has been detected
872(C<$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.
793 881
794If 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
795that automatically removes the callback again when it is destroyed. See 883that automatically removes the callback again when it is destroyed. See
796L<Coro::BDB> for a case where this is useful. 884L<Coro::BDB> for a case where this is useful.
797 885
800If 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
801before or after loading AnyEvent), then they will called directly after 889before or after loading AnyEvent), then they will called directly after
802the event loop has been chosen. 890the event loop has been chosen.
803 891
804You should check C<$AnyEvent::MODEL> before adding to this array, though: 892You should check C<$AnyEvent::MODEL> before adding to this array, though:
805if it contains a true value then the event loop has already been detected, 893if it is defined then the event loop has already been detected, and the
806and the array will be ignored. 894array will be ignored.
807 895
808Best 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.
809 903
810=back 904=back
811 905
812=head1 WHAT TO DO IN A MODULE 906=head1 WHAT TO DO IN A MODULE
813 907
868 962
869 963
870=head1 OTHER MODULES 964=head1 OTHER MODULES
871 965
872The following is a non-exhaustive list of additional modules that use 966The following is a non-exhaustive list of additional modules that use
873AnyEvent and can therefore be mixed easily with other AnyEvent modules 967AnyEvent 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 968modules and other event loops in the same program. Some of the modules
875available via CPAN. 969come with AnyEvent, most are available via CPAN.
876 970
877=over 4 971=over 4
878 972
879=item L<AnyEvent::Util> 973=item L<AnyEvent::Util>
880 974
889 983
890=item L<AnyEvent::Handle> 984=item L<AnyEvent::Handle>
891 985
892Provide read and write buffers, manages watchers for reads and writes, 986Provide read and write buffers, manages watchers for reads and writes,
893supports 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
894non-blocking SSL/TLS. 988non-blocking SSL/TLS (via L<AnyEvent::TLS>.
895 989
896=item L<AnyEvent::DNS> 990=item L<AnyEvent::DNS>
897 991
898Provides rich asynchronous DNS resolver capabilities. 992Provides rich asynchronous DNS resolver capabilities.
899 993
927 1021
928=item L<AnyEvent::GPSD> 1022=item L<AnyEvent::GPSD>
929 1023
930A non-blocking interface to gpsd, a daemon delivering GPS information. 1024A non-blocking interface to gpsd, a daemon delivering GPS information.
931 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
932=item L<AnyEvent::IGS> 1035=item L<AnyEvent::IGS>
933 1036
934A non-blocking interface to the Internet Go Server protocol (used by 1037A non-blocking interface to the Internet Go Server protocol (used by
935L<App::IGS>). 1038L<App::IGS>).
936 1039
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> 1040=item L<Net::FCP>
946 1041
947AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1042AnyEvent-based implementation of the Freenet Client Protocol, birthplace
948of AnyEvent. 1043of AnyEvent.
949 1044
953 1048
954=item L<Coro> 1049=item L<Coro>
955 1050
956Has special support for AnyEvent via L<Coro::AnyEvent>. 1051Has special support for AnyEvent via L<Coro::AnyEvent>.
957 1052
958=item L<IO::Lambda>
959
960The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
961
962=back 1053=back
963 1054
964=cut 1055=cut
965 1056
966package AnyEvent; 1057package AnyEvent;
967 1058
1059# basically a tuned-down version of common::sense
1060sub common_sense {
968no warnings; 1061 # no warnings
1062 ${^WARNING_BITS} ^= ${^WARNING_BITS};
969use strict qw(vars subs); 1063 # use strict vars subs
1064 $^H |= 0x00000600;
1065}
970 1066
1067BEGIN { AnyEvent::common_sense }
1068
971use Carp; 1069use Carp ();
972 1070
973our $VERSION = 4.8; 1071our $VERSION = 4.85;
974our $MODEL; 1072our $MODEL;
975 1073
976our $AUTOLOAD; 1074our $AUTOLOAD;
977our @ISA; 1075our @ISA;
978 1076
979our @REGISTRY; 1077our @REGISTRY;
980 1078
981our $WIN32; 1079our $WIN32;
1080
1081our $VERBOSE;
982 1082
983BEGIN { 1083BEGIN {
984 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1084 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
985 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1085 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
986 1086
987 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1087 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
988 if ${^TAINT}; 1088 if ${^TAINT};
989}
990 1089
991our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1090 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1091
1092}
1093
1094our $MAX_SIGNAL_LATENCY = 10;
992 1095
993our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1096our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
994 1097
995{ 1098{
996 my $idx; 1099 my $idx;
1004 [Event:: => AnyEvent::Impl::Event::], 1107 [Event:: => AnyEvent::Impl::Event::],
1005 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1108 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1006 # everything below here will not be autoprobed 1109 # everything below here will not be autoprobed
1007 # as the pureperl backend should work everywhere 1110 # as the pureperl backend should work everywhere
1008 # and is usually faster 1111 # and is usually faster
1009 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1010 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1112 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1011 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1113 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1114 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1012 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1115 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1013 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1116 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1014 [Wx:: => AnyEvent::Impl::POE::], 1117 [Wx:: => AnyEvent::Impl::POE::],
1015 [Prima:: => AnyEvent::Impl::POE::], 1118 [Prima:: => AnyEvent::Impl::POE::],
1016 # IO::Async is just too broken - we would need workaorunds for its 1119 # IO::Async is just too broken - we would need workarounds for its
1017 # byzantine signal and broken child handling, among others. 1120 # byzantine signal and broken child handling, among others.
1018 # IO::Async is rather hard to detect, as it doesn't have any 1121 # IO::Async is rather hard to detect, as it doesn't have any
1019 # obvious default class. 1122 # obvious default class.
1020# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1123# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1021# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1124# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1047 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1150 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1048} 1151}
1049 1152
1050sub detect() { 1153sub detect() {
1051 unless ($MODEL) { 1154 unless ($MODEL) {
1052 no strict 'refs';
1053 local $SIG{__DIE__}; 1155 local $SIG{__DIE__};
1054 1156
1055 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1157 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1056 my $model = "AnyEvent::Impl::$1"; 1158 my $model = "AnyEvent::Impl::$1";
1057 if (eval "require $model") { 1159 if (eval "require $model") {
1058 $MODEL = $model; 1160 $MODEL = $model;
1059 warn "AnyEvent: loaded model '$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 $VERBOSE >= 2;
1060 } else { 1162 } else {
1061 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1163 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1062 } 1164 }
1063 } 1165 }
1064 1166
1065 # check for already loaded models 1167 # check for already loaded models
1066 unless ($MODEL) { 1168 unless ($MODEL) {
1067 for (@REGISTRY, @models) { 1169 for (@REGISTRY, @models) {
1068 my ($package, $model) = @$_; 1170 my ($package, $model) = @$_;
1069 if (${"$package\::VERSION"} > 0) { 1171 if (${"$package\::VERSION"} > 0) {
1070 if (eval "require $model") { 1172 if (eval "require $model") {
1071 $MODEL = $model; 1173 $MODEL = $model;
1072 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1174 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1073 last; 1175 last;
1074 } 1176 }
1075 } 1177 }
1076 } 1178 }
1077 1179
1082 my ($package, $model) = @$_; 1184 my ($package, $model) = @$_;
1083 if (eval "require $package" 1185 if (eval "require $package"
1084 and ${"$package\::VERSION"} > 0 1186 and ${"$package\::VERSION"} > 0
1085 and eval "require $model") { 1187 and eval "require $model") {
1086 $MODEL = $model; 1188 $MODEL = $model;
1087 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1189 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1088 last; 1190 last;
1089 } 1191 }
1090 } 1192 }
1091 1193
1092 $MODEL 1194 $MODEL
1108 1210
1109sub AUTOLOAD { 1211sub AUTOLOAD {
1110 (my $func = $AUTOLOAD) =~ s/.*://; 1212 (my $func = $AUTOLOAD) =~ s/.*://;
1111 1213
1112 $method{$func} 1214 $method{$func}
1113 or croak "$func: not a valid method for AnyEvent objects"; 1215 or Carp::croak "$func: not a valid method for AnyEvent objects";
1114 1216
1115 detect unless $MODEL; 1217 detect unless $MODEL;
1116 1218
1117 my $class = shift; 1219 my $class = shift;
1118 $class->$func (@_); 1220 $class->$func (@_);
1123# 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).
1124sub _dupfh($$;$$) { 1226sub _dupfh($$;$$) {
1125 my ($poll, $fh, $r, $w) = @_; 1227 my ($poll, $fh, $r, $w) = @_;
1126 1228
1127 # cygwin requires the fh mode to be matching, unix doesn't 1229 # cygwin requires the fh mode to be matching, unix doesn't
1128 my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">"); 1230 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1129 1231
1130 open my $fh2, "$mode&", $fh 1232 open my $fh2, $mode, $fh
1131 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,"; 1233 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1132 1234
1133 # we assume CLOEXEC is already set by perl in all important cases 1235 # we assume CLOEXEC is already set by perl in all important cases
1134 1236
1135 ($fh2, $rw) 1237 ($fh2, $rw)
1137 1239
1138package AnyEvent::Base; 1240package AnyEvent::Base;
1139 1241
1140# default implementations for many methods 1242# default implementations for many methods
1141 1243
1142BEGIN { 1244sub _time {
1245 # probe for availability of Time::HiRes
1143 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;
1144 *_time = \&Time::HiRes::time; 1248 *_time = \&Time::HiRes::time;
1145 # if (eval "use POSIX (); (POSIX::times())... 1249 # if (eval "use POSIX (); (POSIX::times())...
1146 } else { 1250 } else {
1251 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1147 *_time = sub { time }; # epic fail 1252 *_time = sub { time }; # epic fail
1148 } 1253 }
1254
1255 &_time
1149} 1256}
1150 1257
1151sub time { _time } 1258sub time { _time }
1152sub now { _time } 1259sub now { _time }
1153sub now_update { } 1260sub now_update { }
1158 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1265 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1159} 1266}
1160 1267
1161# default implementation for ->signal 1268# default implementation for ->signal
1162 1269
1270our $HAVE_ASYNC_INTERRUPT;
1163our ($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);
1164 1274
1165sub _signal_exec { 1275sub _signal_exec {
1276 $HAVE_ASYNC_INTERRUPT
1277 ? $SIGPIPE_R->drain
1166 sysread $SIGPIPE_R, my $dummy, 4; 1278 : sysread $SIGPIPE_R, my $dummy, 9;
1167 1279
1168 while (%SIG_EV) { 1280 while (%SIG_EV) {
1169 for (keys %SIG_EV) { 1281 for (keys %SIG_EV) {
1170 delete $SIG_EV{$_}; 1282 delete $SIG_EV{$_};
1171 $_->() for values %{ $SIG_CB{$_} || {} }; 1283 $_->() for values %{ $SIG_CB{$_} || {} };
1172 } 1284 }
1173 } 1285 }
1174} 1286}
1175 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, $arg{cb}], "AnyEvent::Base::signal"
1344}
1345
1176sub signal { 1346sub signal {
1177 my (undef, %arg) = @_; 1347 # probe for availability of Async::Interrupt
1348 if (!$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 $VERBOSE >= 8;
1178 1350
1179 unless ($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
1180 require Fcntl; 1358 require Fcntl;
1181 1359
1182 if (AnyEvent::WIN32) { 1360 if (AnyEvent::WIN32) {
1183 require AnyEvent::Util; 1361 require AnyEvent::Util;
1184 1362
1199 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";
1200 1378
1201 $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);
1202 } 1380 }
1203 1381
1204 my $signal = uc $arg{signal} 1382 *signal = \&_signal;
1205 or Carp::croak "required option 'signal' is missing"; 1383 &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, $arg{cb}], "AnyEvent::Base::signal"
1215} 1384}
1216 1385
1217sub AnyEvent::Base::signal::DESTROY { 1386sub AnyEvent::Base::signal::DESTROY {
1218 my ($signal, $cb) = @{$_[0]}; 1387 my ($signal, $cb) = @{$_[0]};
1219 1388
1389 _sig_del;
1390
1220 delete $SIG_CB{$signal}{$cb}; 1391 delete $SIG_CB{$signal}{$cb};
1221 1392
1393 $HAVE_ASYNC_INTERRUPT
1394 ? delete $SIG_ASY{$signal}
1222 # delete doesn't work with older perls - they then 1395 : # delete doesn't work with older perls - they then
1223 # print weird messages, or just unconditionally exit 1396 # print weird messages, or just unconditionally exit
1224 # instead of getting the default action. 1397 # instead of getting the default action.
1398 undef $SIG{$signal}
1225 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1399 unless keys %{ $SIG_CB{$signal} };
1226} 1400}
1227 1401
1228# default implementation for ->child 1402# default implementation for ->child
1229 1403
1230our %PID_CB; 1404our %PID_CB;
1232our $CHLD_DELAY_W; 1406our $CHLD_DELAY_W;
1233our $WNOHANG; 1407our $WNOHANG;
1234 1408
1235sub _sigchld { 1409sub _sigchld {
1236 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1410 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1411 $_->($pid, $?)
1237 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1412 for values %{ $PID_CB{$pid} || {} },
1238 (values %{ $PID_CB{0} || {} }); 1413 values %{ $PID_CB{0} || {} };
1239 } 1414 }
1240} 1415}
1241 1416
1242sub child { 1417sub child {
1243 my (undef, %arg) = @_; 1418 my (undef, %arg) = @_;
1245 defined (my $pid = $arg{pid} + 0) 1420 defined (my $pid = $arg{pid} + 0)
1246 or Carp::croak "required option 'pid' is missing"; 1421 or Carp::croak "required option 'pid' is missing";
1247 1422
1248 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1423 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1249 1424
1425 # WNOHANG is almost cetrainly 1 everywhere
1426 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1427 ? 1
1250 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1428 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1251 1429
1252 unless ($CHLD_W) { 1430 unless ($CHLD_W) {
1253 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1431 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1254 # 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
1255 &_sigchld; 1433 &_sigchld;
1307 1485
1308our @ISA = AnyEvent::CondVar::Base::; 1486our @ISA = AnyEvent::CondVar::Base::;
1309 1487
1310package AnyEvent::CondVar::Base; 1488package AnyEvent::CondVar::Base;
1311 1489
1312use overload 1490#use overload
1313 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1491# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1314 fallback => 1; 1492# fallback => 1;
1493
1494# save 300+ kilobytes by dirtily hardcoding overloading
1495${"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;
1315 1501
1316sub _send { 1502sub _send {
1317 # nop 1503 # nop
1318} 1504}
1319 1505
1332sub ready { 1518sub ready {
1333 $_[0]{_ae_sent} 1519 $_[0]{_ae_sent}
1334} 1520}
1335 1521
1336sub _wait { 1522sub _wait {
1523 $WAITING
1524 and !$_[0]{_ae_sent}
1525 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1526
1527 local $WAITING = 1;
1337 AnyEvent->one_event while !$_[0]{_ae_sent}; 1528 AnyEvent->one_event while !$_[0]{_ae_sent};
1338} 1529}
1339 1530
1340sub recv { 1531sub recv {
1341 $_[0]->_wait; 1532 $_[0]->_wait;
1403C<PERL_ANYEVENT_MODEL>. 1594C<PERL_ANYEVENT_MODEL>.
1404 1595
1405When 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
1406model it chooses. 1597model it chooses.
1407 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
1408=item C<PERL_ANYEVENT_STRICT> 1602=item C<PERL_ANYEVENT_STRICT>
1409 1603
1410AnyEvent does not do much argument checking by default, as thorough 1604AnyEvent does not do much argument checking by default, as thorough
1411argument checking is very costly. Setting this variable to a true value 1605argument checking is very costly. Setting this variable to a true value
1412will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1606will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1413check 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,
1414it will croak. 1608it will croak.
1415 1609
1416In other words, enables "strict" mode. 1610In other words, enables "strict" mode.
1417 1611
1418Unlike C<use strict>, it is definitely recommended to keep it off in 1612Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1419production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1613>>, it is definitely recommended to keep it off in production. Keeping
1420developing programs can be very useful, however. 1614C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1615can be very useful, however.
1421 1616
1422=item C<PERL_ANYEVENT_MODEL> 1617=item C<PERL_ANYEVENT_MODEL>
1423 1618
1424This 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
1425auto detection and -probing kicks in. It must be a string consisting 1620auto detection and -probing kicks in. It must be a string consisting
1487 1682
1488When neither C<ca_file> nor C<ca_path> was specified during 1683When neither C<ca_file> nor C<ca_path> was specified during
1489L<AnyEvent::TLS> context creation, and either of these environment 1684L<AnyEvent::TLS> context creation, and either of these environment
1490variables exist, they will be used to specify CA certificate locations 1685variables exist, they will be used to specify CA certificate locations
1491instead of a system-dependent default. 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.
1492 1692
1493=back 1693=back
1494 1694
1495=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1695=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1496 1696
2035 2235
2036A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2236A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2037emulation for event loops that do not support them natively. Also, some 2237emulation for event loops that do not support them natively. Also, some
2038event loops install a similar handler. 2238event loops install a similar handler.
2039 2239
2040If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will 2240Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2041reset it to default, to avoid losing child exit statuses. 2241AnyEvent will reset it to default, to avoid losing child exit statuses.
2042 2242
2043=item SIGPIPE 2243=item SIGPIPE
2044 2244
2045A 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>
2046when AnyEvent gets loaded. 2246when AnyEvent gets loaded.
2064 if $SIG{CHLD} eq 'IGNORE'; 2264 if $SIG{CHLD} eq 'IGNORE';
2065 2265
2066$SIG{PIPE} = sub { } 2266$SIG{PIPE} = sub { }
2067 unless defined $SIG{PIPE}; 2267 unless defined $SIG{PIPE};
2068 2268
2269=head1 RECOMMENDED/OPTIONAL MODULES
2270
2271One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2272it's built-in modules) are required to use it.
2273
2274That does not mean that AnyEvent won't take advantage of some additional
2275modules if they are installed.
2276
2277This section epxlains which additional modules will be used, and how they
2278affect AnyEvent's operetion.
2279
2280=over 4
2281
2282=item L<Async::Interrupt>
2283
2284This slightly arcane module is used to implement fast signal handling: To
2285my knowledge, there is no way to do completely race-free and quick
2286signal handling in pure perl. To ensure that signals still get
2287delivered, AnyEvent will start an interval timer to wake up perl (and
2288catch the signals) with some delay (default is 10 seconds, look for
2289C<$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
2345
2346
2069=head1 FORK 2347=head1 FORK
2070 2348
2071Most 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
2072because 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>
2073calls. Only L<EV> is fully fork-aware. 2351calls. Only L<EV> is fully fork-aware.
2074 2352
2075If 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
2076watcher 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.
2077 2356
2078 2357
2079=head1 SECURITY CONSIDERATIONS 2358=head1 SECURITY CONSIDERATIONS
2080 2359
2081AnyEvent can be forced to load any event model via 2360AnyEvent can be forced to load any event model via
2119L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2398L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2120 2399
2121Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2400Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2122L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2401L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2123L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2402L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2124L<AnyEvent::Impl::POE>. 2403L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
2125 2404
2126Non-blocking file handles, sockets, TCP clients and 2405Non-blocking file handles, sockets, TCP clients and
2127servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2406servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2128 2407
2129Asynchronous DNS: L<AnyEvent::DNS>. 2408Asynchronous DNS: L<AnyEvent::DNS>.
2130 2409
2131Coroutine 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>,
2132 2412
2133Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2413Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2414L<AnyEvent::HTTP>.
2134 2415
2135 2416
2136=head1 AUTHOR 2417=head1 AUTHOR
2137 2418
2138 Marc Lehmann <schmorp@schmorp.de> 2419 Marc Lehmann <schmorp@schmorp.de>

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