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Revision 1.229 by root, Wed Jul 8 02:01:12 2009 UTC vs.
Revision 1.248 by root, Sat Jul 18 22:27:10 2009 UTC

361invocation, and callback invocation will be synchronous. Synchronous means 361invocation, and callback invocation will be synchronous. Synchronous means
362that it might take a while until the signal gets handled by the process, 362that it might take a while until the signal gets handled by the process,
363but it is guaranteed not to interrupt any other callbacks. 363but it is guaranteed not to interrupt any other callbacks.
364 364
365The main advantage of using these watchers is that you can share a signal 365The main advantage of using these watchers is that you can share a signal
366between multiple watchers. 366between multiple watchers, and AnyEvent will ensure that signals will not
367interrupt your program at bad times.
367 368
368This watcher might use C<%SIG>, so programs overwriting those signals 369This watcher might use C<%SIG> (depending on the event loop used),
369directly will likely not work correctly. 370so programs overwriting those signals directly will likely not work
371correctly.
370 372
371Example: exit on SIGINT 373Example: exit on SIGINT
372 374
373 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 375 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
376
377=head3 Signal Races, Delays and Workarounds
378
379Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
380callbacks to signals in a generic way, which is a pity, as you cannot do
381race-free signal handling in perl. AnyEvent will try to do it's best, but
382in some cases, signals will be delayed. The maximum time a signal might
383be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
384seconds). This variable can be changed only before the first signal
385watcher is created, and should be left alone otherwise. Higher values
386will cause fewer spurious wake-ups, which is better for power and CPU
387saving. All these problems can be avoided by installing the optional
388L<Async::Interrupt> module. This will not work with inherently broken
389event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
390currently, as POE does it's own workaround with one-second latency). With
391those, you just have to suffer the delays.
374 392
375=head2 CHILD PROCESS WATCHERS 393=head2 CHILD PROCESS WATCHERS
376 394
377You can also watch on a child process exit and catch its exit status. 395You can also watch on a child process exit and catch its exit status.
378 396
403 421
404This means you cannot create a child watcher as the very first 422This means you cannot create a child watcher as the very first
405thing in an AnyEvent program, you I<have> to create at least one 423thing in an AnyEvent program, you I<have> to create at least one
406watcher before you C<fork> the child (alternatively, you can call 424watcher before you C<fork> the child (alternatively, you can call
407C<AnyEvent::detect>). 425C<AnyEvent::detect>).
426
427As most event loops do not support waiting for child events, they will be
428emulated by AnyEvent in most cases, in which the latency and race problems
429mentioned in the description of signal watchers apply.
408 430
409Example: fork a process and wait for it 431Example: fork a process and wait for it
410 432
411 my $done = AnyEvent->condvar; 433 my $done = AnyEvent->condvar;
412 434
463 485
464If you are familiar with some event loops you will know that all of them 486If you are familiar with some event loops you will know that all of them
465require you to run some blocking "loop", "run" or similar function that 487require you to run some blocking "loop", "run" or similar function that
466will actively watch for new events and call your callbacks. 488will actively watch for new events and call your callbacks.
467 489
468AnyEvent is different, it expects somebody else to run the event loop and 490AnyEvent is slightly different: it expects somebody else to run the event
469will only block when necessary (usually when told by the user). 491loop and will only block when necessary (usually when told by the user).
470 492
471The instrument to do that is called a "condition variable", so called 493The instrument to do that is called a "condition variable", so called
472because they represent a condition that must become true. 494because they represent a condition that must become true.
473 495
496Now is probably a good time to look at the examples further below.
497
474Condition variables can be created by calling the C<< AnyEvent->condvar 498Condition variables can be created by calling the C<< AnyEvent->condvar
475>> method, usually without arguments. The only argument pair allowed is 499>> method, usually without arguments. The only argument pair allowed is
476
477C<cb>, which specifies a callback to be called when the condition variable 500C<cb>, which specifies a callback to be called when the condition variable
478becomes true, with the condition variable as the first argument (but not 501becomes true, with the condition variable as the first argument (but not
479the results). 502the results).
480 503
481After creation, the condition variable is "false" until it becomes "true" 504After creation, the condition variable is "false" until it becomes "true"
530 after => 1, 553 after => 1,
531 cb => sub { $result_ready->send }, 554 cb => sub { $result_ready->send },
532 ); 555 );
533 556
534 # this "blocks" (while handling events) till the callback 557 # this "blocks" (while handling events) till the callback
535 # calls send 558 # calls -<send
536 $result_ready->recv; 559 $result_ready->recv;
537 560
538Example: wait for a timer, but take advantage of the fact that 561Example: wait for a timer, but take advantage of the fact that condition
539condition variables are also code references. 562variables are also callable directly.
540 563
541 my $done = AnyEvent->condvar; 564 my $done = AnyEvent->condvar;
542 my $delay = AnyEvent->timer (after => 5, cb => $done); 565 my $delay = AnyEvent->timer (after => 5, cb => $done);
543 $done->recv; 566 $done->recv;
544 567
550 573
551 ... 574 ...
552 575
553 my @info = $couchdb->info->recv; 576 my @info = $couchdb->info->recv;
554 577
555And this is how you would just ste a callback to be called whenever the 578And this is how you would just set a callback to be called whenever the
556results are available: 579results are available:
557 580
558 $couchdb->info->cb (sub { 581 $couchdb->info->cb (sub {
559 my @info = $_[0]->recv; 582 my @info = $_[0]->recv;
560 }); 583 });
578immediately from within send. 601immediately from within send.
579 602
580Any arguments passed to the C<send> call will be returned by all 603Any arguments passed to the C<send> call will be returned by all
581future C<< ->recv >> calls. 604future C<< ->recv >> calls.
582 605
583Condition variables are overloaded so one can call them directly 606Condition variables are overloaded so one can call them directly (as if
584(as a code reference). Calling them directly is the same as calling 607they were a code reference). Calling them directly is the same as calling
585C<send>. Note, however, that many C-based event loops do not handle 608C<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).
591 609
592=item $cv->croak ($error) 610=item $cv->croak ($error)
593 611
594Similar to send, but causes all call's to C<< ->recv >> to invoke 612Similar to send, but causes all call's to C<< ->recv >> to invoke
595C<Carp::croak> with the given error message/object/scalar. 613C<Carp::croak> with the given error message/object/scalar.
596 614
597This can be used to signal any errors to the condition variable 615This can be used to signal any errors to the condition variable
598user/consumer. 616user/consumer. Doing it this way instead of calling C<croak> directly
617delays the error detetcion, but has the overwhelmign advantage that it
618diagnoses the error at the place where the result is expected, and not
619deep in some event clalback without connection to the actual code causing
620the problem.
599 621
600=item $cv->begin ([group callback]) 622=item $cv->begin ([group callback])
601 623
602=item $cv->end 624=item $cv->end
603 625
699function will call C<croak>. 721function will call C<croak>.
700 722
701In list context, all parameters passed to C<send> will be returned, 723In list context, all parameters passed to C<send> will be returned,
702in scalar context only the first one will be returned. 724in scalar context only the first one will be returned.
703 725
726Note that doing a blocking wait in a callback is not supported by any
727event loop, that is, recursive invocation of a blocking C<< ->recv
728>> is not allowed, and the C<recv> call will C<croak> if such a
729condition is detected. This condition can be slightly loosened by using
730L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
731any thread that doesn't run the event loop itself.
732
704Not all event models support a blocking wait - some die in that case 733Not all event models support a blocking wait - some die in that case
705(programs might want to do that to stay interactive), so I<if you are 734(programs might want to do that to stay interactive), so I<if you are
706using this from a module, never require a blocking wait>, but let the 735using this from a module, never require a blocking wait>. Instead, let the
707caller decide whether the call will block or not (for example, by coupling 736caller decide whether the call will block or not (for example, by coupling
708condition variables with some kind of request results and supporting 737condition variables with some kind of request results and supporting
709callbacks so the caller knows that getting the result will not block, 738callbacks so the caller knows that getting the result will not block,
710while still supporting blocking waits if the caller so desires). 739while still supporting blocking waits if the caller so desires).
711 740
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 741You can ensure that C<< -recv >> never blocks by setting a callback and
724only calling C<< ->recv >> from within that callback (or at a later 742only calling C<< ->recv >> from within that callback (or at a later
725time). This will work even when the event loop does not support blocking 743time). This will work even when the event loop does not support blocking
726waits otherwise. 744waits otherwise.
727 745
740variable itself. Calling C<recv> inside the callback or at any later time 758variable itself. Calling C<recv> inside the callback or at any later time
741is guaranteed not to block. 759is guaranteed not to block.
742 760
743=back 761=back
744 762
763=head1 SUPPORTED EVENT LOOPS/BACKENDS
764
765The available backend classes are (every class has its own manpage):
766
767=over 4
768
769=item Backends that are autoprobed when no other event loop can be found.
770
771EV is the preferred backend when no other event loop seems to be in
772use. If EV is not installed, then AnyEvent will try Event, and, failing
773that, will fall back to its own pure-perl implementation, which is
774available everywhere as it comes with AnyEvent itself.
775
776 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
777 AnyEvent::Impl::Event based on Event, very stable, few glitches.
778 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
779
780=item Backends that are transparently being picked up when they are used.
781
782These will be used when they are currently loaded when the first watcher
783is created, in which case it is assumed that the application is using
784them. This means that AnyEvent will automatically pick the right backend
785when the main program loads an event module before anything starts to
786create watchers. Nothing special needs to be done by the main program.
787
788 AnyEvent::Impl::Glib based on Glib, slow but very stable.
789 AnyEvent::Impl::Tk based on Tk, very broken.
790 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
791 AnyEvent::Impl::POE based on POE, very slow, some limitations.
792
793=item Backends with special needs.
794
795Qt requires the Qt::Application to be instantiated first, but will
796otherwise be picked up automatically. As long as the main program
797instantiates the application before any AnyEvent watchers are created,
798everything should just work.
799
800 AnyEvent::Impl::Qt based on Qt.
801
802Support for IO::Async can only be partial, as it is too broken and
803architecturally limited to even support the AnyEvent API. It also
804is the only event loop that needs the loop to be set explicitly, so
805it can only be used by a main program knowing about AnyEvent. See
806L<AnyEvent::Impl::Async> for the gory details.
807
808 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
809
810=item Event loops that are indirectly supported via other backends.
811
812Some event loops can be supported via other modules:
813
814There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
815
816B<WxWidgets> has no support for watching file handles. However, you can
817use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
818polls 20 times per second, which was considered to be too horrible to even
819consider for AnyEvent.
820
821B<Prima> is not supported as nobody seems to be using it, but it has a POE
822backend, so it can be supported through POE.
823
824AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
825load L<POE> when detecting them, in the hope that POE will pick them up,
826in which case everything will be automatic.
827
828=back
829
745=head1 GLOBAL VARIABLES AND FUNCTIONS 830=head1 GLOBAL VARIABLES AND FUNCTIONS
746 831
832These are not normally required to use AnyEvent, but can be useful to
833write AnyEvent extension modules.
834
747=over 4 835=over 4
748 836
749=item $AnyEvent::MODEL 837=item $AnyEvent::MODEL
750 838
751Contains C<undef> until the first watcher is being created. Then it 839Contains C<undef> until the first watcher is being created, before the
840backend has been autodetected.
841
752contains the event model that is being used, which is the name of the 842Afterwards it contains the event model that is being used, which is the
753Perl class implementing the model. This class is usually one of the 843name 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 844of 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>). 845case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756 846will 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.
781 847
782=item AnyEvent::detect 848=item AnyEvent::detect
783 849
784Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 850Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785if necessary. You should only call this function right before you would 851if necessary. You should only call this function right before you would
786have created an AnyEvent watcher anyway, that is, as late as possible at 852have created an AnyEvent watcher anyway, that is, as late as possible at
787runtime. 853runtime, and not e.g. while initialising of your module.
854
855If you need to do some initialisation before AnyEvent watchers are
856created, use C<post_detect>.
788 857
789=item $guard = AnyEvent::post_detect { BLOCK } 858=item $guard = AnyEvent::post_detect { BLOCK }
790 859
791Arranges for the code block to be executed as soon as the event model is 860Arranges for the code block to be executed as soon as the event model is
792autodetected (or immediately if this has already happened). 861autodetected (or immediately if this has already happened).
862
863The block will be executed I<after> the actual backend has been detected
864(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
865created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
866other initialisations - see the sources of L<AnyEvent::Strict> or
867L<AnyEvent::AIO> to see how this is used.
868
869The most common usage is to create some global watchers, without forcing
870event module detection too early, for example, L<AnyEvent::AIO> creates
871and installs the global L<IO::AIO> watcher in a C<post_detect> block to
872avoid autodetecting the event module at load time.
793 873
794If called in scalar or list context, then it creates and returns an object 874If called in scalar or list context, then it creates and returns an object
795that automatically removes the callback again when it is destroyed. See 875that automatically removes the callback again when it is destroyed. See
796L<Coro::BDB> for a case where this is useful. 876L<Coro::BDB> for a case where this is useful.
797 877
800If there are any code references in this array (you can C<push> to it 880If there are any code references in this array (you can C<push> to it
801before or after loading AnyEvent), then they will called directly after 881before or after loading AnyEvent), then they will called directly after
802the event loop has been chosen. 882the event loop has been chosen.
803 883
804You should check C<$AnyEvent::MODEL> before adding to this array, though: 884You should check C<$AnyEvent::MODEL> before adding to this array, though:
805if it contains a true value then the event loop has already been detected, 885if it is defined then the event loop has already been detected, and the
806and the array will be ignored. 886array will be ignored.
807 887
808Best use C<AnyEvent::post_detect { BLOCK }> instead. 888Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
889it,as it takes care of these details.
890
891This variable is mainly useful for modules that can do something useful
892when AnyEvent is used and thus want to know when it is initialised, but do
893not need to even load it by default. This array provides the means to hook
894into AnyEvent passively, without loading it.
809 895
810=back 896=back
811 897
812=head1 WHAT TO DO IN A MODULE 898=head1 WHAT TO DO IN A MODULE
813 899
868 954
869 955
870=head1 OTHER MODULES 956=head1 OTHER MODULES
871 957
872The following is a non-exhaustive list of additional modules that use 958The following is a non-exhaustive list of additional modules that use
873AnyEvent and can therefore be mixed easily with other AnyEvent modules 959AnyEvent 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 960modules and other event loops in the same program. Some of the modules
875available via CPAN. 961come with AnyEvent, most are available via CPAN.
876 962
877=over 4 963=over 4
878 964
879=item L<AnyEvent::Util> 965=item L<AnyEvent::Util>
880 966
889 975
890=item L<AnyEvent::Handle> 976=item L<AnyEvent::Handle>
891 977
892Provide read and write buffers, manages watchers for reads and writes, 978Provide read and write buffers, manages watchers for reads and writes,
893supports raw and formatted I/O, I/O queued and fully transparent and 979supports raw and formatted I/O, I/O queued and fully transparent and
894non-blocking SSL/TLS. 980non-blocking SSL/TLS (via L<AnyEvent::TLS>.
895 981
896=item L<AnyEvent::DNS> 982=item L<AnyEvent::DNS>
897 983
898Provides rich asynchronous DNS resolver capabilities. 984Provides rich asynchronous DNS resolver capabilities.
899 985
927 1013
928=item L<AnyEvent::GPSD> 1014=item L<AnyEvent::GPSD>
929 1015
930A non-blocking interface to gpsd, a daemon delivering GPS information. 1016A non-blocking interface to gpsd, a daemon delivering GPS information.
931 1017
1018=item L<AnyEvent::IRC>
1019
1020AnyEvent based IRC client module family (replacing the older Net::IRC3).
1021
1022=item L<AnyEvent::XMPP>
1023
1024AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1025Net::XMPP2>.
1026
932=item L<AnyEvent::IGS> 1027=item L<AnyEvent::IGS>
933 1028
934A non-blocking interface to the Internet Go Server protocol (used by 1029A non-blocking interface to the Internet Go Server protocol (used by
935L<App::IGS>). 1030L<App::IGS>).
936 1031
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> 1032=item L<Net::FCP>
946 1033
947AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1034AnyEvent-based implementation of the Freenet Client Protocol, birthplace
948of AnyEvent. 1035of AnyEvent.
949 1036
953 1040
954=item L<Coro> 1041=item L<Coro>
955 1042
956Has special support for AnyEvent via L<Coro::AnyEvent>. 1043Has special support for AnyEvent via L<Coro::AnyEvent>.
957 1044
958=item L<IO::Lambda>
959
960The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
961
962=back 1045=back
963 1046
964=cut 1047=cut
965 1048
966package AnyEvent; 1049package AnyEvent;
967 1050
1051# basically a tuned-down version of common::sense
1052sub common_sense {
968no warnings; 1053 # no warnings
1054 ${^WARNING_BITS} ^= ${^WARNING_BITS};
969use strict qw(vars subs); 1055 # use strict vars subs
1056 $^H |= 0x00000600;
1057}
970 1058
1059BEGIN { AnyEvent::common_sense }
1060
971use Carp; 1061use Carp ();
972 1062
973our $VERSION = 4.8; 1063our $VERSION = 4.85;
974our $MODEL; 1064our $MODEL;
975 1065
976our $AUTOLOAD; 1066our $AUTOLOAD;
977our @ISA; 1067our @ISA;
978 1068
979our @REGISTRY; 1069our @REGISTRY;
980 1070
981our $WIN32; 1071our $WIN32;
1072
1073our $VERBOSE;
982 1074
983BEGIN { 1075BEGIN {
984 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1076 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
985 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1077 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
986 1078
987 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1079 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
988 if ${^TAINT}; 1080 if ${^TAINT};
989}
990 1081
991our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1082 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1083
1084}
1085
1086our $MAX_SIGNAL_LATENCY = 10;
992 1087
993our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1088our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
994 1089
995{ 1090{
996 my $idx; 1091 my $idx;
1004 [Event:: => AnyEvent::Impl::Event::], 1099 [Event:: => AnyEvent::Impl::Event::],
1005 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1100 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1006 # everything below here will not be autoprobed 1101 # everything below here will not be autoprobed
1007 # as the pureperl backend should work everywhere 1102 # as the pureperl backend should work everywhere
1008 # and is usually faster 1103 # and is usually faster
1009 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1010 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1104 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1011 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1105 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1106 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1012 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1107 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1013 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1108 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1014 [Wx:: => AnyEvent::Impl::POE::], 1109 [Wx:: => AnyEvent::Impl::POE::],
1015 [Prima:: => AnyEvent::Impl::POE::], 1110 [Prima:: => AnyEvent::Impl::POE::],
1016 # IO::Async is just too broken - we would need workaorunds for its 1111 # IO::Async is just too broken - we would need workarounds for its
1017 # byzantine signal and broken child handling, among others. 1112 # byzantine signal and broken child handling, among others.
1018 # IO::Async is rather hard to detect, as it doesn't have any 1113 # IO::Async is rather hard to detect, as it doesn't have any
1019 # obvious default class. 1114 # obvious default class.
1020# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1115# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1021# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1116# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1047 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1142 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1048} 1143}
1049 1144
1050sub detect() { 1145sub detect() {
1051 unless ($MODEL) { 1146 unless ($MODEL) {
1052 no strict 'refs';
1053 local $SIG{__DIE__}; 1147 local $SIG{__DIE__};
1054 1148
1055 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1149 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1056 my $model = "AnyEvent::Impl::$1"; 1150 my $model = "AnyEvent::Impl::$1";
1057 if (eval "require $model") { 1151 if (eval "require $model") {
1058 $MODEL = $model; 1152 $MODEL = $model;
1059 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1153 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1060 } else { 1154 } else {
1061 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1155 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1062 } 1156 }
1063 } 1157 }
1064 1158
1065 # check for already loaded models 1159 # check for already loaded models
1066 unless ($MODEL) { 1160 unless ($MODEL) {
1067 for (@REGISTRY, @models) { 1161 for (@REGISTRY, @models) {
1068 my ($package, $model) = @$_; 1162 my ($package, $model) = @$_;
1069 if (${"$package\::VERSION"} > 0) { 1163 if (${"$package\::VERSION"} > 0) {
1070 if (eval "require $model") { 1164 if (eval "require $model") {
1071 $MODEL = $model; 1165 $MODEL = $model;
1072 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1166 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1073 last; 1167 last;
1074 } 1168 }
1075 } 1169 }
1076 } 1170 }
1077 1171
1082 my ($package, $model) = @$_; 1176 my ($package, $model) = @$_;
1083 if (eval "require $package" 1177 if (eval "require $package"
1084 and ${"$package\::VERSION"} > 0 1178 and ${"$package\::VERSION"} > 0
1085 and eval "require $model") { 1179 and eval "require $model") {
1086 $MODEL = $model; 1180 $MODEL = $model;
1087 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1181 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1088 last; 1182 last;
1089 } 1183 }
1090 } 1184 }
1091 1185
1092 $MODEL 1186 $MODEL
1108 1202
1109sub AUTOLOAD { 1203sub AUTOLOAD {
1110 (my $func = $AUTOLOAD) =~ s/.*://; 1204 (my $func = $AUTOLOAD) =~ s/.*://;
1111 1205
1112 $method{$func} 1206 $method{$func}
1113 or croak "$func: not a valid method for AnyEvent objects"; 1207 or Carp::croak "$func: not a valid method for AnyEvent objects";
1114 1208
1115 detect unless $MODEL; 1209 detect unless $MODEL;
1116 1210
1117 my $class = shift; 1211 my $class = shift;
1118 $class->$func (@_); 1212 $class->$func (@_);
1123# allow only one watcher per fd, so we dup it to get a different one). 1217# allow only one watcher per fd, so we dup it to get a different one).
1124sub _dupfh($$;$$) { 1218sub _dupfh($$;$$) {
1125 my ($poll, $fh, $r, $w) = @_; 1219 my ($poll, $fh, $r, $w) = @_;
1126 1220
1127 # cygwin requires the fh mode to be matching, unix doesn't 1221 # cygwin requires the fh mode to be matching, unix doesn't
1128 my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">"); 1222 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1129 1223
1130 open my $fh2, "$mode&", $fh 1224 open my $fh2, $mode, $fh
1131 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,"; 1225 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1132 1226
1133 # we assume CLOEXEC is already set by perl in all important cases 1227 # we assume CLOEXEC is already set by perl in all important cases
1134 1228
1135 ($fh2, $rw) 1229 ($fh2, $rw)
1137 1231
1138package AnyEvent::Base; 1232package AnyEvent::Base;
1139 1233
1140# default implementations for many methods 1234# default implementations for many methods
1141 1235
1142BEGIN { 1236sub _time {
1237 # probe for availability of Time::HiRes
1143 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1238 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1239 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1144 *_time = \&Time::HiRes::time; 1240 *_time = \&Time::HiRes::time;
1145 # if (eval "use POSIX (); (POSIX::times())... 1241 # if (eval "use POSIX (); (POSIX::times())...
1146 } else { 1242 } else {
1243 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1147 *_time = sub { time }; # epic fail 1244 *_time = sub { time }; # epic fail
1148 } 1245 }
1246
1247 &_time
1149} 1248}
1150 1249
1151sub time { _time } 1250sub time { _time }
1152sub now { _time } 1251sub now { _time }
1153sub now_update { } 1252sub now_update { }
1158 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1257 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1159} 1258}
1160 1259
1161# default implementation for ->signal 1260# default implementation for ->signal
1162 1261
1262our $HAVE_ASYNC_INTERRUPT;
1163our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1263our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1264our (%SIG_ASY, %SIG_ASY_W);
1265our ($SIG_COUNT, $SIG_TW);
1164 1266
1165sub _signal_exec { 1267sub _signal_exec {
1268 $HAVE_ASYNC_INTERRUPT
1269 ? $SIGPIPE_R->drain
1166 sysread $SIGPIPE_R, my $dummy, 4; 1270 : sysread $SIGPIPE_R, my $dummy, 9;
1167 1271
1168 while (%SIG_EV) { 1272 while (%SIG_EV) {
1169 for (keys %SIG_EV) { 1273 for (keys %SIG_EV) {
1170 delete $SIG_EV{$_}; 1274 delete $SIG_EV{$_};
1171 $_->() for values %{ $SIG_CB{$_} || {} }; 1275 $_->() for values %{ $SIG_CB{$_} || {} };
1172 } 1276 }
1173 } 1277 }
1174} 1278}
1175 1279
1280# install a dumym wakeupw atcher to reduce signal catching latency
1281sub _sig_add() {
1282 unless ($SIG_COUNT++) {
1283 # try to align timer on a full-second boundary, if possible
1284 my $NOW = AnyEvent->now;
1285
1286 $SIG_TW = AnyEvent->timer (
1287 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1288 interval => $MAX_SIGNAL_LATENCY,
1289 cb => sub { }, # just for the PERL_ASYNC_CHECK
1290 );
1291 }
1292}
1293
1294sub _sig_del {
1295 undef $SIG_TW
1296 unless --$SIG_COUNT;
1297}
1298
1299sub _signal {
1300 my (undef, %arg) = @_;
1301
1302 my $signal = uc $arg{signal}
1303 or Carp::croak "required option 'signal' is missing";
1304
1305 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1306
1307 if ($HAVE_ASYNC_INTERRUPT) {
1308 # async::interrupt
1309
1310 $SIG_ASY{$signal} ||= do {
1311 my $asy = new Async::Interrupt
1312 cb => sub { undef $SIG_EV{$signal} },
1313 signal => $signal,
1314 pipe => [$SIGPIPE_R->filenos],
1315 ;
1316 $asy->pipe_autodrain (0);
1317
1318 $asy
1319 };
1320
1321 } else {
1322 # pure perl
1323
1324 $SIG{$signal} ||= sub {
1325 local $!;
1326 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1327 undef $SIG_EV{$signal};
1328 };
1329
1330 # can't do signal processing without introducing races in pure perl,
1331 # so limit the signal latency.
1332 _sig_add;
1333 }
1334
1335 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1336}
1337
1176sub signal { 1338sub signal {
1177 my (undef, %arg) = @_; 1339 # probe for availability of Async::Interrupt
1340 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1341 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1178 1342
1179 unless ($SIGPIPE_R) { 1343 $HAVE_ASYNC_INTERRUPT = 1;
1344 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1345 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1346
1347 } else {
1348 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1349
1180 require Fcntl; 1350 require Fcntl;
1181 1351
1182 if (AnyEvent::WIN32) { 1352 if (AnyEvent::WIN32) {
1183 require AnyEvent::Util; 1353 require AnyEvent::Util;
1184 1354
1199 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1369 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1200 1370
1201 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); 1371 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1202 } 1372 }
1203 1373
1204 my $signal = uc $arg{signal} 1374 *signal = \&_signal;
1205 or Carp::croak "required option 'signal' is missing"; 1375 &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, $arg{cb}], "AnyEvent::Base::signal"
1215} 1376}
1216 1377
1217sub AnyEvent::Base::signal::DESTROY { 1378sub AnyEvent::Base::signal::DESTROY {
1218 my ($signal, $cb) = @{$_[0]}; 1379 my ($signal, $cb) = @{$_[0]};
1219 1380
1381 _sig_del;
1382
1220 delete $SIG_CB{$signal}{$cb}; 1383 delete $SIG_CB{$signal}{$cb};
1221 1384
1385 $HAVE_ASYNC_INTERRUPT
1386 ? delete $SIG_ASY{$signal}
1222 # delete doesn't work with older perls - they then 1387 : # delete doesn't work with older perls - they then
1223 # print weird messages, or just unconditionally exit 1388 # print weird messages, or just unconditionally exit
1224 # instead of getting the default action. 1389 # instead of getting the default action.
1390 undef $SIG{$signal}
1225 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1391 unless keys %{ $SIG_CB{$signal} };
1226} 1392}
1227 1393
1228# default implementation for ->child 1394# default implementation for ->child
1229 1395
1230our %PID_CB; 1396our %PID_CB;
1232our $CHLD_DELAY_W; 1398our $CHLD_DELAY_W;
1233our $WNOHANG; 1399our $WNOHANG;
1234 1400
1235sub _sigchld { 1401sub _sigchld {
1236 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1402 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1403 $_->($pid, $?)
1237 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1404 for values %{ $PID_CB{$pid} || {} },
1238 (values %{ $PID_CB{0} || {} }); 1405 values %{ $PID_CB{0} || {} };
1239 } 1406 }
1240} 1407}
1241 1408
1242sub child { 1409sub child {
1243 my (undef, %arg) = @_; 1410 my (undef, %arg) = @_;
1245 defined (my $pid = $arg{pid} + 0) 1412 defined (my $pid = $arg{pid} + 0)
1246 or Carp::croak "required option 'pid' is missing"; 1413 or Carp::croak "required option 'pid' is missing";
1247 1414
1248 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1415 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1249 1416
1417 # WNOHANG is almost cetrainly 1 everywhere
1418 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1419 ? 1
1250 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1420 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1251 1421
1252 unless ($CHLD_W) { 1422 unless ($CHLD_W) {
1253 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1423 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1254 # child could be a zombie already, so make at least one round 1424 # child could be a zombie already, so make at least one round
1255 &_sigchld; 1425 &_sigchld;
1307 1477
1308our @ISA = AnyEvent::CondVar::Base::; 1478our @ISA = AnyEvent::CondVar::Base::;
1309 1479
1310package AnyEvent::CondVar::Base; 1480package AnyEvent::CondVar::Base;
1311 1481
1312use overload 1482#use overload
1313 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1483# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1314 fallback => 1; 1484# fallback => 1;
1485
1486# save 300+ kilobytes by dirtily hardcoding overloading
1487${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1488*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1489*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1490${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1491
1492our $WAITING;
1315 1493
1316sub _send { 1494sub _send {
1317 # nop 1495 # nop
1318} 1496}
1319 1497
1332sub ready { 1510sub ready {
1333 $_[0]{_ae_sent} 1511 $_[0]{_ae_sent}
1334} 1512}
1335 1513
1336sub _wait { 1514sub _wait {
1515 $WAITING
1516 and !$_[0]{_ae_sent}
1517 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1518
1519 local $WAITING = 1;
1337 AnyEvent->one_event while !$_[0]{_ae_sent}; 1520 AnyEvent->one_event while !$_[0]{_ae_sent};
1338} 1521}
1339 1522
1340sub recv { 1523sub recv {
1341 $_[0]->_wait; 1524 $_[0]->_wait;
1403C<PERL_ANYEVENT_MODEL>. 1586C<PERL_ANYEVENT_MODEL>.
1404 1587
1405When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1588When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1406model it chooses. 1589model it chooses.
1407 1590
1591When set to C<8> or higher, then AnyEvent will report extra information on
1592which optional modules it loads and how it implements certain features.
1593
1408=item C<PERL_ANYEVENT_STRICT> 1594=item C<PERL_ANYEVENT_STRICT>
1409 1595
1410AnyEvent does not do much argument checking by default, as thorough 1596AnyEvent does not do much argument checking by default, as thorough
1411argument checking is very costly. Setting this variable to a true value 1597argument checking is very costly. Setting this variable to a true value
1412will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1598will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1413check the arguments passed to most method calls. If it finds any problems, 1599check the arguments passed to most method calls. If it finds any problems,
1414it will croak. 1600it will croak.
1415 1601
1416In other words, enables "strict" mode. 1602In other words, enables "strict" mode.
1417 1603
1418Unlike C<use strict>, it is definitely recommended to keep it off in 1604Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1419production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1605>>, it is definitely recommended to keep it off in production. Keeping
1420developing programs can be very useful, however. 1606C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1607can be very useful, however.
1421 1608
1422=item C<PERL_ANYEVENT_MODEL> 1609=item C<PERL_ANYEVENT_MODEL>
1423 1610
1424This can be used to specify the event model to be used by AnyEvent, before 1611This can be used to specify the event model to be used by AnyEvent, before
1425auto detection and -probing kicks in. It must be a string consisting 1612auto detection and -probing kicks in. It must be a string consisting
1487 1674
1488When neither C<ca_file> nor C<ca_path> was specified during 1675When neither C<ca_file> nor C<ca_path> was specified during
1489L<AnyEvent::TLS> context creation, and either of these environment 1676L<AnyEvent::TLS> context creation, and either of these environment
1490variables exist, they will be used to specify CA certificate locations 1677variables exist, they will be used to specify CA certificate locations
1491instead of a system-dependent default. 1678instead of a system-dependent default.
1679
1680=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1681
1682When these are set to C<1>, then the respective modules are not
1683loaded. Mostly good for testing AnyEvent itself.
1492 1684
1493=back 1685=back
1494 1686
1495=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1687=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1496 1688
2035 2227
2036A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2228A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2037emulation for event loops that do not support them natively. Also, some 2229emulation for event loops that do not support them natively. Also, some
2038event loops install a similar handler. 2230event loops install a similar handler.
2039 2231
2040If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will 2232Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2041reset it to default, to avoid losing child exit statuses. 2233AnyEvent will reset it to default, to avoid losing child exit statuses.
2042 2234
2043=item SIGPIPE 2235=item SIGPIPE
2044 2236
2045A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2237A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2046when AnyEvent gets loaded. 2238when AnyEvent gets loaded.
2064 if $SIG{CHLD} eq 'IGNORE'; 2256 if $SIG{CHLD} eq 'IGNORE';
2065 2257
2066$SIG{PIPE} = sub { } 2258$SIG{PIPE} = sub { }
2067 unless defined $SIG{PIPE}; 2259 unless defined $SIG{PIPE};
2068 2260
2261=head1 RECOMMENDED/OPTIONAL MODULES
2262
2263One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2264it's built-in modules) are required to use it.
2265
2266That does not mean that AnyEvent won't take advantage of some additional
2267modules if they are installed.
2268
2269This section epxlains which additional modules will be used, and how they
2270affect AnyEvent's operetion.
2271
2272=over 4
2273
2274=item L<Async::Interrupt>
2275
2276This slightly arcane module is used to implement fast signal handling: To
2277my knowledge, there is no way to do completely race-free and quick
2278signal handling in pure perl. To ensure that signals still get
2279delivered, AnyEvent will start an interval timer to wake up perl (and
2280catch the signals) with some delay (default is 10 seconds, look for
2281C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2282
2283If this module is available, then it will be used to implement signal
2284catching, which means that signals will not be delayed, and the event loop
2285will not be interrupted regularly, which is more efficient (And good for
2286battery life on laptops).
2287
2288This affects not just the pure-perl event loop, but also other event loops
2289that have no signal handling on their own (e.g. Glib, Tk, Qt).
2290
2291Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2292and either employ their own workarounds (POE) or use AnyEvent's workaround
2293(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2294does nothing for those backends.
2295
2296=item L<EV>
2297
2298This module isn't really "optional", as it is simply one of the backend
2299event loops that AnyEvent can use. However, it is simply the best event
2300loop available in terms of features, speed and stability: It supports
2301the AnyEvent API optimally, implements all the watcher types in XS, does
2302automatic timer adjustments even when no monotonic clock is available,
2303can take avdantage of advanced kernel interfaces such as C<epoll> and
2304C<kqueue>, and is the fastest backend I<by far>. You can even embed
2305L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2306
2307=item L<Guard>
2308
2309The guard module, when used, will be used to implement
2310C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2311lot less memory), but otherwise doesn't affect guard operation much. It is
2312purely used for performance.
2313
2314=item L<JSON> and L<JSON::XS>
2315
2316This module is required when you want to read or write JSON data via
2317L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2318advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2319
2320In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2321installed.
2322
2323=item L<Net::SSLeay>
2324
2325Implementing TLS/SSL in Perl is certainly interesting, but not very
2326worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2327the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2328
2329=item L<Time::HiRes>
2330
2331This module is part of perl since release 5.008. It will be used when the
2332chosen event library does not come with a timing source on it's own. The
2333pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2334try to use a monotonic clock for timing stability.
2335
2336=back
2337
2338
2069=head1 FORK 2339=head1 FORK
2070 2340
2071Most event libraries are not fork-safe. The ones who are usually are 2341Most event libraries are not fork-safe. The ones who are usually are
2072because they rely on inefficient but fork-safe C<select> or C<poll> 2342because they rely on inefficient but fork-safe C<select> or C<poll>
2073calls. Only L<EV> is fully fork-aware. 2343calls. Only L<EV> is fully fork-aware.
2074 2344
2075If you have to fork, you must either do so I<before> creating your first 2345If you have to fork, you must either do so I<before> creating your first
2076watcher OR you must not use AnyEvent at all in the child. 2346watcher OR you must not use AnyEvent at all in the child OR you must do
2347something completely out of the scope of AnyEvent.
2077 2348
2078 2349
2079=head1 SECURITY CONSIDERATIONS 2350=head1 SECURITY CONSIDERATIONS
2080 2351
2081AnyEvent can be forced to load any event model via 2352AnyEvent can be forced to load any event model via
2119L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2390L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2120 2391
2121Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2392Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2122L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2393L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2123L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2394L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2124L<AnyEvent::Impl::POE>. 2395L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
2125 2396
2126Non-blocking file handles, sockets, TCP clients and 2397Non-blocking file handles, sockets, TCP clients and
2127servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2398servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2128 2399
2129Asynchronous DNS: L<AnyEvent::DNS>. 2400Asynchronous DNS: L<AnyEvent::DNS>.
2130 2401
2131Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2402Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2403L<Coro::Event>,
2132 2404
2133Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2405Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2406L<AnyEvent::HTTP>.
2134 2407
2135 2408
2136=head1 AUTHOR 2409=head1 AUTHOR
2137 2410
2138 Marc Lehmann <schmorp@schmorp.de> 2411 Marc Lehmann <schmorp@schmorp.de>

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