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1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - events independent of event loop implementation
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
6event loops. 6event loops.
7 7
8=head1 SYNOPSIS 8=head1 SYNOPSIS
40=head1 INTRODUCTION/TUTORIAL 40=head1 INTRODUCTION/TUTORIAL
41 41
42This manpage is mainly a reference manual. If you are interested 42This manpage is mainly a reference manual. If you are interested
43in a tutorial or some gentle introduction, have a look at the 43in a tutorial or some gentle introduction, have a look at the
44L<AnyEvent::Intro> manpage. 44L<AnyEvent::Intro> manpage.
45
46=head1 SUPPORT
47
48There is a mailinglist for discussing all things AnyEvent, and an IRC
49channel, too.
50
51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52Respository>, at L<http://anyevent.schmorp.de>, for more info.
45 53
46=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47 55
48Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49nowadays. So what is different about AnyEvent? 57nowadays. So what is different about AnyEvent?
176=head2 I/O WATCHERS 184=head2 I/O WATCHERS
177 185
178You can create an I/O watcher by calling the C<< AnyEvent->io >> method 186You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179with the following mandatory key-value pairs as arguments: 187with the following mandatory key-value pairs as arguments:
180 188
181C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch 189C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182for events (AnyEvent might or might not keep a reference to this file 190for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which 191handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets, 192non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files 193most character devices, pipes, fifos and so on, but not for example files
186or block devices. 194or block devices.
361invocation, and callback invocation will be synchronous. Synchronous means 369invocation, and callback invocation will be synchronous. Synchronous means
362that it might take a while until the signal gets handled by the process, 370that it might take a while until the signal gets handled by the process,
363but it is guaranteed not to interrupt any other callbacks. 371but it is guaranteed not to interrupt any other callbacks.
364 372
365The main advantage of using these watchers is that you can share a signal 373The main advantage of using these watchers is that you can share a signal
366between multiple watchers. 374between multiple watchers, and AnyEvent will ensure that signals will not
375interrupt your program at bad times.
367 376
368This watcher might use C<%SIG>, so programs overwriting those signals 377This watcher might use C<%SIG> (depending on the event loop used),
369directly will likely not work correctly. 378so programs overwriting those signals directly will likely not work
379correctly.
370 380
371Example: exit on SIGINT 381Example: exit on SIGINT
372 382
373 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 383 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384
385=head3 Signal Races, Delays and Workarounds
386
387Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
388callbacks to signals in a generic way, which is a pity, as you cannot do
389race-free signal handling in perl. AnyEvent will try to do it's best, but
390in some cases, signals will be delayed. The maximum time a signal might
391be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
392seconds). This variable can be changed only before the first signal
393watcher is created, and should be left alone otherwise. Higher values
394will cause fewer spurious wake-ups, which is better for power and CPU
395saving. All these problems can be avoided by installing the optional
396L<Async::Interrupt> module. This will not work with inherently broken
397event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
398currently, as POE does it's own workaround with one-second latency). With
399those, you just have to suffer the delays.
374 400
375=head2 CHILD PROCESS WATCHERS 401=head2 CHILD PROCESS WATCHERS
376 402
377You can also watch on a child process exit and catch its exit status. 403You can also watch on a child process exit and catch its exit status.
378 404
403 429
404This means you cannot create a child watcher as the very first 430This means you cannot create a child watcher as the very first
405thing in an AnyEvent program, you I<have> to create at least one 431thing in an AnyEvent program, you I<have> to create at least one
406watcher before you C<fork> the child (alternatively, you can call 432watcher before you C<fork> the child (alternatively, you can call
407C<AnyEvent::detect>). 433C<AnyEvent::detect>).
434
435As most event loops do not support waiting for child events, they will be
436emulated by AnyEvent in most cases, in which the latency and race problems
437mentioned in the description of signal watchers apply.
408 438
409Example: fork a process and wait for it 439Example: fork a process and wait for it
410 440
411 my $done = AnyEvent->condvar; 441 my $done = AnyEvent->condvar;
412 442
463 493
464If you are familiar with some event loops you will know that all of them 494If you are familiar with some event loops you will know that all of them
465require you to run some blocking "loop", "run" or similar function that 495require you to run some blocking "loop", "run" or similar function that
466will actively watch for new events and call your callbacks. 496will actively watch for new events and call your callbacks.
467 497
468AnyEvent is different, it expects somebody else to run the event loop and 498AnyEvent is slightly different: it expects somebody else to run the event
469will only block when necessary (usually when told by the user). 499loop and will only block when necessary (usually when told by the user).
470 500
471The instrument to do that is called a "condition variable", so called 501The instrument to do that is called a "condition variable", so called
472because they represent a condition that must become true. 502because they represent a condition that must become true.
473 503
504Now is probably a good time to look at the examples further below.
505
474Condition variables can be created by calling the C<< AnyEvent->condvar 506Condition variables can be created by calling the C<< AnyEvent->condvar
475>> method, usually without arguments. The only argument pair allowed is 507>> method, usually without arguments. The only argument pair allowed is
476
477C<cb>, which specifies a callback to be called when the condition variable 508C<cb>, which specifies a callback to be called when the condition variable
478becomes true, with the condition variable as the first argument (but not 509becomes true, with the condition variable as the first argument (but not
479the results). 510the results).
480 511
481After creation, the condition variable is "false" until it becomes "true" 512After creation, the condition variable is "false" until it becomes "true"
486Condition variables are similar to callbacks, except that you can 517Condition variables are similar to callbacks, except that you can
487optionally wait for them. They can also be called merge points - points 518optionally wait for them. They can also be called merge points - points
488in time where multiple outstanding events have been processed. And yet 519in time where multiple outstanding events have been processed. And yet
489another way to call them is transactions - each condition variable can be 520another way to call them is transactions - each condition variable can be
490used to represent a transaction, which finishes at some point and delivers 521used to represent a transaction, which finishes at some point and delivers
491a result. 522a result. And yet some people know them as "futures" - a promise to
523compute/deliver something that you can wait for.
492 524
493Condition variables are very useful to signal that something has finished, 525Condition variables are very useful to signal that something has finished,
494for example, if you write a module that does asynchronous http requests, 526for example, if you write a module that does asynchronous http requests,
495then a condition variable would be the ideal candidate to signal the 527then a condition variable would be the ideal candidate to signal the
496availability of results. The user can either act when the callback is 528availability of results. The user can either act when the callback is
530 after => 1, 562 after => 1,
531 cb => sub { $result_ready->send }, 563 cb => sub { $result_ready->send },
532 ); 564 );
533 565
534 # this "blocks" (while handling events) till the callback 566 # this "blocks" (while handling events) till the callback
535 # calls send 567 # calls -<send
536 $result_ready->recv; 568 $result_ready->recv;
537 569
538Example: wait for a timer, but take advantage of the fact that 570Example: wait for a timer, but take advantage of the fact that condition
539condition variables are also code references. 571variables are also callable directly.
540 572
541 my $done = AnyEvent->condvar; 573 my $done = AnyEvent->condvar;
542 my $delay = AnyEvent->timer (after => 5, cb => $done); 574 my $delay = AnyEvent->timer (after => 5, cb => $done);
543 $done->recv; 575 $done->recv;
544 576
550 582
551 ... 583 ...
552 584
553 my @info = $couchdb->info->recv; 585 my @info = $couchdb->info->recv;
554 586
555And this is how you would just ste a callback to be called whenever the 587And this is how you would just set a callback to be called whenever the
556results are available: 588results are available:
557 589
558 $couchdb->info->cb (sub { 590 $couchdb->info->cb (sub {
559 my @info = $_[0]->recv; 591 my @info = $_[0]->recv;
560 }); 592 });
578immediately from within send. 610immediately from within send.
579 611
580Any arguments passed to the C<send> call will be returned by all 612Any arguments passed to the C<send> call will be returned by all
581future C<< ->recv >> calls. 613future C<< ->recv >> calls.
582 614
583Condition variables are overloaded so one can call them directly 615Condition variables are overloaded so one can call them directly (as if
584(as a code reference). Calling them directly is the same as calling 616they were a code reference). Calling them directly is the same as calling
585C<send>. Note, however, that many C-based event loops do not handle 617C<send>.
586overloading, so as tempting as it may be, passing a condition variable
587instead of a callback does not work. Both the pure perl and EV loops
588support overloading, however, as well as all functions that use perl to
589invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590example).
591 618
592=item $cv->croak ($error) 619=item $cv->croak ($error)
593 620
594Similar to send, but causes all call's to C<< ->recv >> to invoke 621Similar to send, but causes all call's to C<< ->recv >> to invoke
595C<Carp::croak> with the given error message/object/scalar. 622C<Carp::croak> with the given error message/object/scalar.
596 623
597This can be used to signal any errors to the condition variable 624This can be used to signal any errors to the condition variable
598user/consumer. 625user/consumer. Doing it this way instead of calling C<croak> directly
626delays the error detetcion, but has the overwhelmign advantage that it
627diagnoses the error at the place where the result is expected, and not
628deep in some event clalback without connection to the actual code causing
629the problem.
599 630
600=item $cv->begin ([group callback]) 631=item $cv->begin ([group callback])
601 632
602=item $cv->end 633=item $cv->end
603 634
699function will call C<croak>. 730function will call C<croak>.
700 731
701In list context, all parameters passed to C<send> will be returned, 732In list context, all parameters passed to C<send> will be returned,
702in scalar context only the first one will be returned. 733in scalar context only the first one will be returned.
703 734
735Note that doing a blocking wait in a callback is not supported by any
736event loop, that is, recursive invocation of a blocking C<< ->recv
737>> is not allowed, and the C<recv> call will C<croak> if such a
738condition is detected. This condition can be slightly loosened by using
739L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
740any thread that doesn't run the event loop itself.
741
704Not all event models support a blocking wait - some die in that case 742Not all event models support a blocking wait - some die in that case
705(programs might want to do that to stay interactive), so I<if you are 743(programs might want to do that to stay interactive), so I<if you are
706using this from a module, never require a blocking wait>, but let the 744using this from a module, never require a blocking wait>. Instead, let the
707caller decide whether the call will block or not (for example, by coupling 745caller decide whether the call will block or not (for example, by coupling
708condition variables with some kind of request results and supporting 746condition variables with some kind of request results and supporting
709callbacks so the caller knows that getting the result will not block, 747callbacks so the caller knows that getting the result will not block,
710while still supporting blocking waits if the caller so desires). 748while still supporting blocking waits if the caller so desires).
711 749
712Another reason I<never> to C<< ->recv >> in a module is that you cannot
713sensibly have two C<< ->recv >>'s in parallel, as that would require
714multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715can supply.
716
717The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719versions and also integrates coroutines into AnyEvent, making blocking
720C<< ->recv >> calls perfectly safe as long as they are done from another
721coroutine (one that doesn't run the event loop).
722
723You can ensure that C<< -recv >> never blocks by setting a callback and 750You can ensure that C<< -recv >> never blocks by setting a callback and
724only calling C<< ->recv >> from within that callback (or at a later 751only calling C<< ->recv >> from within that callback (or at a later
725time). This will work even when the event loop does not support blocking 752time). This will work even when the event loop does not support blocking
726waits otherwise. 753waits otherwise.
727 754
740variable itself. Calling C<recv> inside the callback or at any later time 767variable itself. Calling C<recv> inside the callback or at any later time
741is guaranteed not to block. 768is guaranteed not to block.
742 769
743=back 770=back
744 771
772=head1 SUPPORTED EVENT LOOPS/BACKENDS
773
774The available backend classes are (every class has its own manpage):
775
776=over 4
777
778=item Backends that are autoprobed when no other event loop can be found.
779
780EV is the preferred backend when no other event loop seems to be in
781use. If EV is not installed, then AnyEvent will try Event, and, failing
782that, will fall back to its own pure-perl implementation, which is
783available everywhere as it comes with AnyEvent itself.
784
785 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
786 AnyEvent::Impl::Event based on Event, very stable, few glitches.
787 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
788
789=item Backends that are transparently being picked up when they are used.
790
791These will be used when they are currently loaded when the first watcher
792is created, in which case it is assumed that the application is using
793them. This means that AnyEvent will automatically pick the right backend
794when the main program loads an event module before anything starts to
795create watchers. Nothing special needs to be done by the main program.
796
797 AnyEvent::Impl::Glib based on Glib, slow but very stable.
798 AnyEvent::Impl::Tk based on Tk, very broken.
799 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
800 AnyEvent::Impl::POE based on POE, very slow, some limitations.
801
802=item Backends with special needs.
803
804Qt requires the Qt::Application to be instantiated first, but will
805otherwise be picked up automatically. As long as the main program
806instantiates the application before any AnyEvent watchers are created,
807everything should just work.
808
809 AnyEvent::Impl::Qt based on Qt.
810
811Support for IO::Async can only be partial, as it is too broken and
812architecturally limited to even support the AnyEvent API. It also
813is the only event loop that needs the loop to be set explicitly, so
814it can only be used by a main program knowing about AnyEvent. See
815L<AnyEvent::Impl::Async> for the gory details.
816
817 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
818
819=item Event loops that are indirectly supported via other backends.
820
821Some event loops can be supported via other modules:
822
823There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
824
825B<WxWidgets> has no support for watching file handles. However, you can
826use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
827polls 20 times per second, which was considered to be too horrible to even
828consider for AnyEvent.
829
830B<Prima> is not supported as nobody seems to be using it, but it has a POE
831backend, so it can be supported through POE.
832
833AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
834load L<POE> when detecting them, in the hope that POE will pick them up,
835in which case everything will be automatic.
836
837=back
838
745=head1 GLOBAL VARIABLES AND FUNCTIONS 839=head1 GLOBAL VARIABLES AND FUNCTIONS
746 840
841These are not normally required to use AnyEvent, but can be useful to
842write AnyEvent extension modules.
843
747=over 4 844=over 4
748 845
749=item $AnyEvent::MODEL 846=item $AnyEvent::MODEL
750 847
751Contains C<undef> until the first watcher is being created. Then it 848Contains C<undef> until the first watcher is being created, before the
849backend has been autodetected.
850
752contains the event model that is being used, which is the name of the 851Afterwards it contains the event model that is being used, which is the
753Perl class implementing the model. This class is usually one of the 852name of the Perl class implementing the model. This class is usually one
754C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 853of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
755AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 854case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756 855will be C<urxvt::anyevent>).
757The known classes so far are:
758
759 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760 AnyEvent::Impl::Event based on Event, second best choice.
761 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762 AnyEvent::Impl::Glib based on Glib, third-best choice.
763 AnyEvent::Impl::Tk based on Tk, very bad choice.
764 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766 AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768 # warning, support for IO::Async is only partial, as it is too broken
769 # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772There is no support for WxWidgets, as WxWidgets has no support for
773watching file handles. However, you can use WxWidgets through the
774POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775second, which was considered to be too horrible to even consider for
776AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777it's adaptor.
778
779AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780autodetecting them.
781 856
782=item AnyEvent::detect 857=item AnyEvent::detect
783 858
784Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 859Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785if necessary. You should only call this function right before you would 860if necessary. You should only call this function right before you would
786have created an AnyEvent watcher anyway, that is, as late as possible at 861have created an AnyEvent watcher anyway, that is, as late as possible at
787runtime. 862runtime, and not e.g. while initialising of your module.
863
864If you need to do some initialisation before AnyEvent watchers are
865created, use C<post_detect>.
788 866
789=item $guard = AnyEvent::post_detect { BLOCK } 867=item $guard = AnyEvent::post_detect { BLOCK }
790 868
791Arranges for the code block to be executed as soon as the event model is 869Arranges for the code block to be executed as soon as the event model is
792autodetected (or immediately if this has already happened). 870autodetected (or immediately if this has already happened).
871
872The block will be executed I<after> the actual backend has been detected
873(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
874created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
875other initialisations - see the sources of L<AnyEvent::Strict> or
876L<AnyEvent::AIO> to see how this is used.
877
878The most common usage is to create some global watchers, without forcing
879event module detection too early, for example, L<AnyEvent::AIO> creates
880and installs the global L<IO::AIO> watcher in a C<post_detect> block to
881avoid autodetecting the event module at load time.
793 882
794If called in scalar or list context, then it creates and returns an object 883If called in scalar or list context, then it creates and returns an object
795that automatically removes the callback again when it is destroyed. See 884that automatically removes the callback again when it is destroyed. See
796L<Coro::BDB> for a case where this is useful. 885L<Coro::BDB> for a case where this is useful.
797 886
800If there are any code references in this array (you can C<push> to it 889If 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 890before or after loading AnyEvent), then they will called directly after
802the event loop has been chosen. 891the event loop has been chosen.
803 892
804You should check C<$AnyEvent::MODEL> before adding to this array, though: 893You should check C<$AnyEvent::MODEL> before adding to this array, though:
805if it contains a true value then the event loop has already been detected, 894if it is defined then the event loop has already been detected, and the
806and the array will be ignored. 895array will be ignored.
807 896
808Best use C<AnyEvent::post_detect { BLOCK }> instead. 897Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
898it,as it takes care of these details.
899
900This variable is mainly useful for modules that can do something useful
901when AnyEvent is used and thus want to know when it is initialised, but do
902not need to even load it by default. This array provides the means to hook
903into AnyEvent passively, without loading it.
809 904
810=back 905=back
811 906
812=head1 WHAT TO DO IN A MODULE 907=head1 WHAT TO DO IN A MODULE
813 908
868 963
869 964
870=head1 OTHER MODULES 965=head1 OTHER MODULES
871 966
872The following is a non-exhaustive list of additional modules that use 967The following is a non-exhaustive list of additional modules that use
873AnyEvent and can therefore be mixed easily with other AnyEvent modules 968AnyEvent 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 969modules and other event loops in the same program. Some of the modules
875available via CPAN. 970come with AnyEvent, most are available via CPAN.
876 971
877=over 4 972=over 4
878 973
879=item L<AnyEvent::Util> 974=item L<AnyEvent::Util>
880 975
889 984
890=item L<AnyEvent::Handle> 985=item L<AnyEvent::Handle>
891 986
892Provide read and write buffers, manages watchers for reads and writes, 987Provide read and write buffers, manages watchers for reads and writes,
893supports raw and formatted I/O, I/O queued and fully transparent and 988supports raw and formatted I/O, I/O queued and fully transparent and
894non-blocking SSL/TLS. 989non-blocking SSL/TLS (via L<AnyEvent::TLS>.
895 990
896=item L<AnyEvent::DNS> 991=item L<AnyEvent::DNS>
897 992
898Provides rich asynchronous DNS resolver capabilities. 993Provides rich asynchronous DNS resolver capabilities.
899 994
927 1022
928=item L<AnyEvent::GPSD> 1023=item L<AnyEvent::GPSD>
929 1024
930A non-blocking interface to gpsd, a daemon delivering GPS information. 1025A non-blocking interface to gpsd, a daemon delivering GPS information.
931 1026
1027=item L<AnyEvent::IRC>
1028
1029AnyEvent based IRC client module family (replacing the older Net::IRC3).
1030
1031=item L<AnyEvent::XMPP>
1032
1033AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1034Net::XMPP2>.
1035
932=item L<AnyEvent::IGS> 1036=item L<AnyEvent::IGS>
933 1037
934A non-blocking interface to the Internet Go Server protocol (used by 1038A non-blocking interface to the Internet Go Server protocol (used by
935L<App::IGS>). 1039L<App::IGS>).
936 1040
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> 1041=item L<Net::FCP>
946 1042
947AnyEvent-based implementation of the Freenet Client Protocol, birthplace 1043AnyEvent-based implementation of the Freenet Client Protocol, birthplace
948of AnyEvent. 1044of AnyEvent.
949 1045
953 1049
954=item L<Coro> 1050=item L<Coro>
955 1051
956Has special support for AnyEvent via L<Coro::AnyEvent>. 1052Has special support for AnyEvent via L<Coro::AnyEvent>.
957 1053
958=item L<IO::Lambda>
959
960The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
961
962=back 1054=back
963 1055
964=cut 1056=cut
965 1057
966package AnyEvent; 1058package AnyEvent;
967 1059
1060# basically a tuned-down version of common::sense
1061sub common_sense {
968no warnings; 1062 # no warnings
1063 ${^WARNING_BITS} ^= ${^WARNING_BITS};
969use strict qw(vars subs); 1064 # use strict vars subs
1065 $^H |= 0x00000600;
1066}
970 1067
1068BEGIN { AnyEvent::common_sense }
1069
971use Carp; 1070use Carp ();
972 1071
973our $VERSION = 4.45; 1072our $VERSION = 4.86;
974our $MODEL; 1073our $MODEL;
975 1074
976our $AUTOLOAD; 1075our $AUTOLOAD;
977our @ISA; 1076our @ISA;
978 1077
979our @REGISTRY; 1078our @REGISTRY;
980 1079
981our $WIN32; 1080our $WIN32;
1081
1082our $VERBOSE;
982 1083
983BEGIN { 1084BEGIN {
984 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1085 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
985 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1086 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
986 1087
987 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1088 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
988 if ${^TAINT}; 1089 if ${^TAINT};
989}
990 1090
991our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1091 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1092
1093}
1094
1095our $MAX_SIGNAL_LATENCY = 10;
992 1096
993our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1097our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
994 1098
995{ 1099{
996 my $idx; 1100 my $idx;
1004 [Event:: => AnyEvent::Impl::Event::], 1108 [Event:: => AnyEvent::Impl::Event::],
1005 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1109 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1006 # everything below here will not be autoprobed 1110 # everything below here will not be autoprobed
1007 # as the pureperl backend should work everywhere 1111 # as the pureperl backend should work everywhere
1008 # and is usually faster 1112 # and is usually faster
1009 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1010 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1113 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1011 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1114 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1115 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1012 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1116 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1013 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1117 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1014 [Wx:: => AnyEvent::Impl::POE::], 1118 [Wx:: => AnyEvent::Impl::POE::],
1015 [Prima:: => AnyEvent::Impl::POE::], 1119 [Prima:: => AnyEvent::Impl::POE::],
1016 # IO::Async is just too broken - we would need workaorunds for its 1120 # IO::Async is just too broken - we would need workarounds for its
1017 # byzantine signal and broken child handling, among others. 1121 # byzantine signal and broken child handling, among others.
1018 # IO::Async is rather hard to detect, as it doesn't have any 1122 # IO::Async is rather hard to detect, as it doesn't have any
1019 # obvious default class. 1123 # obvious default class.
1020# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1124# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1021# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1125# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1047 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1151 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1048} 1152}
1049 1153
1050sub detect() { 1154sub detect() {
1051 unless ($MODEL) { 1155 unless ($MODEL) {
1052 no strict 'refs';
1053 local $SIG{__DIE__}; 1156 local $SIG{__DIE__};
1054 1157
1055 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1158 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1056 my $model = "AnyEvent::Impl::$1"; 1159 my $model = "AnyEvent::Impl::$1";
1057 if (eval "require $model") { 1160 if (eval "require $model") {
1058 $MODEL = $model; 1161 $MODEL = $model;
1059 warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; 1162 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1060 } else { 1163 } else {
1061 warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; 1164 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1062 } 1165 }
1063 } 1166 }
1064 1167
1065 # check for already loaded models 1168 # check for already loaded models
1066 unless ($MODEL) { 1169 unless ($MODEL) {
1067 for (@REGISTRY, @models) { 1170 for (@REGISTRY, @models) {
1068 my ($package, $model) = @$_; 1171 my ($package, $model) = @$_;
1069 if (${"$package\::VERSION"} > 0) { 1172 if (${"$package\::VERSION"} > 0) {
1070 if (eval "require $model") { 1173 if (eval "require $model") {
1071 $MODEL = $model; 1174 $MODEL = $model;
1072 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1175 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1073 last; 1176 last;
1074 } 1177 }
1075 } 1178 }
1076 } 1179 }
1077 1180
1082 my ($package, $model) = @$_; 1185 my ($package, $model) = @$_;
1083 if (eval "require $package" 1186 if (eval "require $package"
1084 and ${"$package\::VERSION"} > 0 1187 and ${"$package\::VERSION"} > 0
1085 and eval "require $model") { 1188 and eval "require $model") {
1086 $MODEL = $model; 1189 $MODEL = $model;
1087 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1190 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1088 last; 1191 last;
1089 } 1192 }
1090 } 1193 }
1091 1194
1092 $MODEL 1195 $MODEL
1108 1211
1109sub AUTOLOAD { 1212sub AUTOLOAD {
1110 (my $func = $AUTOLOAD) =~ s/.*://; 1213 (my $func = $AUTOLOAD) =~ s/.*://;
1111 1214
1112 $method{$func} 1215 $method{$func}
1113 or croak "$func: not a valid method for AnyEvent objects"; 1216 or Carp::croak "$func: not a valid method for AnyEvent objects";
1114 1217
1115 detect unless $MODEL; 1218 detect unless $MODEL;
1116 1219
1117 my $class = shift; 1220 my $class = shift;
1118 $class->$func (@_); 1221 $class->$func (@_);
1123# allow only one watcher per fd, so we dup it to get a different one). 1226# allow only one watcher per fd, so we dup it to get a different one).
1124sub _dupfh($$;$$) { 1227sub _dupfh($$;$$) {
1125 my ($poll, $fh, $r, $w) = @_; 1228 my ($poll, $fh, $r, $w) = @_;
1126 1229
1127 # cygwin requires the fh mode to be matching, unix doesn't 1230 # cygwin requires the fh mode to be matching, unix doesn't
1128 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1231 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1129 : $poll eq "w" ? ($w, ">")
1130 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1131 1232
1132 open my $fh2, "$mode&" . fileno $fh 1233 open my $fh2, $mode, $fh
1133 or die "cannot dup() filehandle: $!,"; 1234 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1134 1235
1135 # we assume CLOEXEC is already set by perl in all important cases 1236 # we assume CLOEXEC is already set by perl in all important cases
1136 1237
1137 ($fh2, $rw) 1238 ($fh2, $rw)
1138} 1239}
1139 1240
1140package AnyEvent::Base; 1241package AnyEvent::Base;
1141 1242
1142# default implementations for many methods 1243# default implementations for many methods
1143 1244
1144BEGIN { 1245sub _time {
1246 # probe for availability of Time::HiRes
1145 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1247 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1248 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1146 *_time = \&Time::HiRes::time; 1249 *_time = \&Time::HiRes::time;
1147 # if (eval "use POSIX (); (POSIX::times())... 1250 # if (eval "use POSIX (); (POSIX::times())...
1148 } else { 1251 } else {
1252 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1149 *_time = sub { time }; # epic fail 1253 *_time = sub { time }; # epic fail
1150 } 1254 }
1255
1256 &_time
1151} 1257}
1152 1258
1153sub time { _time } 1259sub time { _time }
1154sub now { _time } 1260sub now { _time }
1155sub now_update { } 1261sub now_update { }
1160 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1266 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1161} 1267}
1162 1268
1163# default implementation for ->signal 1269# default implementation for ->signal
1164 1270
1271our $HAVE_ASYNC_INTERRUPT;
1165our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1272our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1273our (%SIG_ASY, %SIG_ASY_W);
1274our ($SIG_COUNT, $SIG_TW);
1166 1275
1167sub _signal_exec { 1276sub _signal_exec {
1277 $HAVE_ASYNC_INTERRUPT
1278 ? $SIGPIPE_R->drain
1168 sysread $SIGPIPE_R, my $dummy, 4; 1279 : sysread $SIGPIPE_R, my $dummy, 9;
1169 1280
1170 while (%SIG_EV) { 1281 while (%SIG_EV) {
1171 for (keys %SIG_EV) { 1282 for (keys %SIG_EV) {
1172 delete $SIG_EV{$_}; 1283 delete $SIG_EV{$_};
1173 $_->() for values %{ $SIG_CB{$_} || {} }; 1284 $_->() for values %{ $SIG_CB{$_} || {} };
1174 } 1285 }
1175 } 1286 }
1176} 1287}
1177 1288
1289# install a dumym wakeupw atcher to reduce signal catching latency
1290sub _sig_add() {
1291 unless ($SIG_COUNT++) {
1292 # try to align timer on a full-second boundary, if possible
1293 my $NOW = AnyEvent->now;
1294
1295 $SIG_TW = AnyEvent->timer (
1296 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1297 interval => $MAX_SIGNAL_LATENCY,
1298 cb => sub { }, # just for the PERL_ASYNC_CHECK
1299 );
1300 }
1301}
1302
1303sub _sig_del {
1304 undef $SIG_TW
1305 unless --$SIG_COUNT;
1306}
1307
1308sub _signal {
1309 my (undef, %arg) = @_;
1310
1311 my $signal = uc $arg{signal}
1312 or Carp::croak "required option 'signal' is missing";
1313
1314 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1315
1316 if ($HAVE_ASYNC_INTERRUPT) {
1317 # async::interrupt
1318
1319 $SIG_ASY{$signal} ||= do {
1320 my $asy = new Async::Interrupt
1321 cb => sub { undef $SIG_EV{$signal} },
1322 signal => $signal,
1323 pipe => [$SIGPIPE_R->filenos],
1324 ;
1325 $asy->pipe_autodrain (0);
1326
1327 $asy
1328 };
1329
1330 } else {
1331 # pure perl
1332
1333 $SIG{$signal} ||= sub {
1334 local $!;
1335 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1336 undef $SIG_EV{$signal};
1337 };
1338
1339 # can't do signal processing without introducing races in pure perl,
1340 # so limit the signal latency.
1341 _sig_add;
1342 }
1343
1344 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1345}
1346
1178sub signal { 1347sub signal {
1179 my (undef, %arg) = @_; 1348 # probe for availability of Async::Interrupt
1349 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1350 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1180 1351
1181 unless ($SIGPIPE_R) { 1352 $HAVE_ASYNC_INTERRUPT = 1;
1353 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1354 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1355
1356 } else {
1357 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1358
1182 require Fcntl; 1359 require Fcntl;
1183 1360
1184 if (AnyEvent::WIN32) { 1361 if (AnyEvent::WIN32) {
1185 require AnyEvent::Util; 1362 require AnyEvent::Util;
1186 1363
1201 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1378 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1202 1379
1203 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); 1380 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1204 } 1381 }
1205 1382
1206 my $signal = uc $arg{signal} 1383 *signal = \&_signal;
1207 or Carp::croak "required option 'signal' is missing"; 1384 &signal
1208
1209 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1210 $SIG{$signal} ||= sub {
1211 local $!;
1212 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1213 undef $SIG_EV{$signal};
1214 };
1215
1216 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1217} 1385}
1218 1386
1219sub AnyEvent::Base::signal::DESTROY { 1387sub AnyEvent::Base::signal::DESTROY {
1220 my ($signal, $cb) = @{$_[0]}; 1388 my ($signal, $cb) = @{$_[0]};
1221 1389
1390 _sig_del;
1391
1222 delete $SIG_CB{$signal}{$cb}; 1392 delete $SIG_CB{$signal}{$cb};
1223 1393
1394 $HAVE_ASYNC_INTERRUPT
1395 ? delete $SIG_ASY{$signal}
1224 # delete doesn't work with older perls - they then 1396 : # delete doesn't work with older perls - they then
1225 # print weird messages, or just unconditionally exit 1397 # print weird messages, or just unconditionally exit
1226 # instead of getting the default action. 1398 # instead of getting the default action.
1399 undef $SIG{$signal}
1227 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1400 unless keys %{ $SIG_CB{$signal} };
1228} 1401}
1229 1402
1230# default implementation for ->child 1403# default implementation for ->child
1231 1404
1232our %PID_CB; 1405our %PID_CB;
1234our $CHLD_DELAY_W; 1407our $CHLD_DELAY_W;
1235our $WNOHANG; 1408our $WNOHANG;
1236 1409
1237sub _sigchld { 1410sub _sigchld {
1238 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1411 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1412 $_->($pid, $?)
1239 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1413 for values %{ $PID_CB{$pid} || {} },
1240 (values %{ $PID_CB{0} || {} }); 1414 values %{ $PID_CB{0} || {} };
1241 } 1415 }
1242} 1416}
1243 1417
1244sub child { 1418sub child {
1245 my (undef, %arg) = @_; 1419 my (undef, %arg) = @_;
1247 defined (my $pid = $arg{pid} + 0) 1421 defined (my $pid = $arg{pid} + 0)
1248 or Carp::croak "required option 'pid' is missing"; 1422 or Carp::croak "required option 'pid' is missing";
1249 1423
1250 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1424 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1251 1425
1426 # WNOHANG is almost cetrainly 1 everywhere
1427 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1428 ? 1
1252 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1429 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1253 1430
1254 unless ($CHLD_W) { 1431 unless ($CHLD_W) {
1255 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1432 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1256 # child could be a zombie already, so make at least one round 1433 # child could be a zombie already, so make at least one round
1257 &_sigchld; 1434 &_sigchld;
1309 1486
1310our @ISA = AnyEvent::CondVar::Base::; 1487our @ISA = AnyEvent::CondVar::Base::;
1311 1488
1312package AnyEvent::CondVar::Base; 1489package AnyEvent::CondVar::Base;
1313 1490
1314use overload 1491#use overload
1315 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1492# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1316 fallback => 1; 1493# fallback => 1;
1494
1495# save 300+ kilobytes by dirtily hardcoding overloading
1496${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1497*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1498*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1499${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1500
1501our $WAITING;
1317 1502
1318sub _send { 1503sub _send {
1319 # nop 1504 # nop
1320} 1505}
1321 1506
1334sub ready { 1519sub ready {
1335 $_[0]{_ae_sent} 1520 $_[0]{_ae_sent}
1336} 1521}
1337 1522
1338sub _wait { 1523sub _wait {
1524 $WAITING
1525 and !$_[0]{_ae_sent}
1526 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1527
1528 local $WAITING = 1;
1339 AnyEvent->one_event while !$_[0]{_ae_sent}; 1529 AnyEvent->one_event while !$_[0]{_ae_sent};
1340} 1530}
1341 1531
1342sub recv { 1532sub recv {
1343 $_[0]->_wait; 1533 $_[0]->_wait;
1405C<PERL_ANYEVENT_MODEL>. 1595C<PERL_ANYEVENT_MODEL>.
1406 1596
1407When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1597When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1408model it chooses. 1598model it chooses.
1409 1599
1600When set to C<8> or higher, then AnyEvent will report extra information on
1601which optional modules it loads and how it implements certain features.
1602
1410=item C<PERL_ANYEVENT_STRICT> 1603=item C<PERL_ANYEVENT_STRICT>
1411 1604
1412AnyEvent does not do much argument checking by default, as thorough 1605AnyEvent does not do much argument checking by default, as thorough
1413argument checking is very costly. Setting this variable to a true value 1606argument checking is very costly. Setting this variable to a true value
1414will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1607will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1415check the arguments passed to most method calls. If it finds any problems, 1608check the arguments passed to most method calls. If it finds any problems,
1416it will croak. 1609it will croak.
1417 1610
1418In other words, enables "strict" mode. 1611In other words, enables "strict" mode.
1419 1612
1420Unlike C<use strict>, it is definitely recommended to keep it off in 1613Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1421production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1614>>, it is definitely recommended to keep it off in production. Keeping
1422developing programs can be very useful, however. 1615C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1616can be very useful, however.
1423 1617
1424=item C<PERL_ANYEVENT_MODEL> 1618=item C<PERL_ANYEVENT_MODEL>
1425 1619
1426This can be used to specify the event model to be used by AnyEvent, before 1620This can be used to specify the event model to be used by AnyEvent, before
1427auto detection and -probing kicks in. It must be a string consisting 1621auto detection and -probing kicks in. It must be a string consisting
1470 1664
1471=item C<PERL_ANYEVENT_MAX_FORKS> 1665=item C<PERL_ANYEVENT_MAX_FORKS>
1472 1666
1473The maximum number of child processes that C<AnyEvent::Util::fork_call> 1667The maximum number of child processes that C<AnyEvent::Util::fork_call>
1474will create in parallel. 1668will create in parallel.
1669
1670=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1671
1672The default value for the C<max_outstanding> parameter for the default DNS
1673resolver - this is the maximum number of parallel DNS requests that are
1674sent to the DNS server.
1675
1676=item C<PERL_ANYEVENT_RESOLV_CONF>
1677
1678The file to use instead of F</etc/resolv.conf> (or OS-specific
1679configuration) in the default resolver. When set to the empty string, no
1680default config will be used.
1681
1682=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1683
1684When neither C<ca_file> nor C<ca_path> was specified during
1685L<AnyEvent::TLS> context creation, and either of these environment
1686variables exist, they will be used to specify CA certificate locations
1687instead of a system-dependent default.
1688
1689=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1690
1691When these are set to C<1>, then the respective modules are not
1692loaded. Mostly good for testing AnyEvent itself.
1475 1693
1476=back 1694=back
1477 1695
1478=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1696=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1479 1697
2018 2236
2019A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 2237A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2020emulation for event loops that do not support them natively. Also, some 2238emulation for event loops that do not support them natively. Also, some
2021event loops install a similar handler. 2239event loops install a similar handler.
2022 2240
2023If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will 2241Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2024reset it to default, to avoid losing child exit statuses. 2242AnyEvent will reset it to default, to avoid losing child exit statuses.
2025 2243
2026=item SIGPIPE 2244=item SIGPIPE
2027 2245
2028A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 2246A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2029when AnyEvent gets loaded. 2247when AnyEvent gets loaded.
2047 if $SIG{CHLD} eq 'IGNORE'; 2265 if $SIG{CHLD} eq 'IGNORE';
2048 2266
2049$SIG{PIPE} = sub { } 2267$SIG{PIPE} = sub { }
2050 unless defined $SIG{PIPE}; 2268 unless defined $SIG{PIPE};
2051 2269
2270=head1 RECOMMENDED/OPTIONAL MODULES
2271
2272One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2273it's built-in modules) are required to use it.
2274
2275That does not mean that AnyEvent won't take advantage of some additional
2276modules if they are installed.
2277
2278This section epxlains which additional modules will be used, and how they
2279affect AnyEvent's operetion.
2280
2281=over 4
2282
2283=item L<Async::Interrupt>
2284
2285This slightly arcane module is used to implement fast signal handling: To
2286my knowledge, there is no way to do completely race-free and quick
2287signal handling in pure perl. To ensure that signals still get
2288delivered, AnyEvent will start an interval timer to wake up perl (and
2289catch the signals) with some delay (default is 10 seconds, look for
2290C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2291
2292If this module is available, then it will be used to implement signal
2293catching, which means that signals will not be delayed, and the event loop
2294will not be interrupted regularly, which is more efficient (And good for
2295battery life on laptops).
2296
2297This affects not just the pure-perl event loop, but also other event loops
2298that have no signal handling on their own (e.g. Glib, Tk, Qt).
2299
2300Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2301and either employ their own workarounds (POE) or use AnyEvent's workaround
2302(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2303does nothing for those backends.
2304
2305=item L<EV>
2306
2307This module isn't really "optional", as it is simply one of the backend
2308event loops that AnyEvent can use. However, it is simply the best event
2309loop available in terms of features, speed and stability: It supports
2310the AnyEvent API optimally, implements all the watcher types in XS, does
2311automatic timer adjustments even when no monotonic clock is available,
2312can take avdantage of advanced kernel interfaces such as C<epoll> and
2313C<kqueue>, and is the fastest backend I<by far>. You can even embed
2314L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2315
2316=item L<Guard>
2317
2318The guard module, when used, will be used to implement
2319C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2320lot less memory), but otherwise doesn't affect guard operation much. It is
2321purely used for performance.
2322
2323=item L<JSON> and L<JSON::XS>
2324
2325This module is required when you want to read or write JSON data via
2326L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2327advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2328
2329In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2330installed.
2331
2332=item L<Net::SSLeay>
2333
2334Implementing TLS/SSL in Perl is certainly interesting, but not very
2335worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2336the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2337
2338=item L<Time::HiRes>
2339
2340This module is part of perl since release 5.008. It will be used when the
2341chosen event library does not come with a timing source on it's own. The
2342pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2343try to use a monotonic clock for timing stability.
2344
2345=back
2346
2347
2052=head1 FORK 2348=head1 FORK
2053 2349
2054Most event libraries are not fork-safe. The ones who are usually are 2350Most event libraries are not fork-safe. The ones who are usually are
2055because they rely on inefficient but fork-safe C<select> or C<poll> 2351because they rely on inefficient but fork-safe C<select> or C<poll>
2056calls. Only L<EV> is fully fork-aware. 2352calls. Only L<EV> is fully fork-aware.
2057 2353
2058If you have to fork, you must either do so I<before> creating your first 2354If you have to fork, you must either do so I<before> creating your first
2059watcher OR you must not use AnyEvent at all in the child. 2355watcher OR you must not use AnyEvent at all in the child OR you must do
2356something completely out of the scope of AnyEvent.
2060 2357
2061 2358
2062=head1 SECURITY CONSIDERATIONS 2359=head1 SECURITY CONSIDERATIONS
2063 2360
2064AnyEvent can be forced to load any event model via 2361AnyEvent can be forced to load any event model via
2102L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2399L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2103 2400
2104Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2401Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2105L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2402L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2106L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2403L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2107L<AnyEvent::Impl::POE>. 2404L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
2108 2405
2109Non-blocking file handles, sockets, TCP clients and 2406Non-blocking file handles, sockets, TCP clients and
2110servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2407servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2111 2408
2112Asynchronous DNS: L<AnyEvent::DNS>. 2409Asynchronous DNS: L<AnyEvent::DNS>.
2113 2410
2114Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2411Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2412L<Coro::Event>,
2115 2413
2116Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2414Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2415L<AnyEvent::HTTP>.
2117 2416
2118 2417
2119=head1 AUTHOR 2418=head1 AUTHOR
2120 2419
2121 Marc Lehmann <schmorp@schmorp.de> 2420 Marc Lehmann <schmorp@schmorp.de>

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