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Revision 1.350 by root, Tue Aug 2 20:02:44 2011 UTC vs.
Revision 1.420 by root, Fri Sep 5 22:17:26 2014 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - the DBI of event loop programming 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt 5EV, Event, Glib, Tk, UV, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async,
6and POE are various supported event loops/environments. 6Qt, FLTK and POE are various supported event loops/environments.
7 7
8=head1 SYNOPSIS 8=head1 SYNOPSIS
9 9
10 use AnyEvent; 10 use AnyEvent;
11 11
121The interface itself is vaguely similar, but not identical to the L<Event> 121The interface itself is vaguely similar, but not identical to the L<Event>
122module. 122module.
123 123
124During the first call of any watcher-creation method, the module tries 124During the first call of any watcher-creation method, the module tries
125to detect the currently loaded event loop by probing whether one of the 125to detect the currently loaded event loop by probing whether one of the
126following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>, 126following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
127L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one 127L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
128found is used. If none are detected, the module tries to load the first 128found is used. If none are detected, the module tries to load the first
129four modules in the order given; but note that if L<EV> is not 129four modules in the order given; but note that if L<EV> is not
130available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so 130available, the pure-perl L<AnyEvent::Loop> should always work, so
131the other two are not normally tried. 131the other two are not normally tried.
132 132
133Because AnyEvent first checks for modules that are already loaded, loading 133Because AnyEvent first checks for modules that are already loaded, loading
134an event model explicitly before first using AnyEvent will likely make 134an event model explicitly before first using AnyEvent will likely make
135that model the default. For example: 135that model the default. For example:
142The I<likely> means that, if any module loads another event model and 142The I<likely> means that, if any module loads another event model and
143starts using it, all bets are off - this case should be very rare though, 143starts using it, all bets are off - this case should be very rare though,
144as very few modules hardcode event loops without announcing this very 144as very few modules hardcode event loops without announcing this very
145loudly. 145loudly.
146 146
147The pure-perl implementation of AnyEvent is called 147The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
148C<AnyEvent::Impl::Perl>. Like other event modules you can load it 148other event modules you can load it explicitly and enjoy the high
149explicitly and enjoy the high availability of that event loop :) 149availability of that event loop :)
150 150
151=head1 WATCHERS 151=head1 WATCHERS
152 152
153AnyEvent has the central concept of a I<watcher>, which is an object that 153AnyEvent has the central concept of a I<watcher>, which is an object that
154stores relevant data for each kind of event you are waiting for, such as 154stores relevant data for each kind of event you are waiting for, such as
271 271
272Example 2: fire an event after 0.5 seconds, then roughly every second. 272Example 2: fire an event after 0.5 seconds, then roughly every second.
273 273
274 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { 274 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
275 warn "timeout\n"; 275 warn "timeout\n";
276 }; 276 });
277 277
278=head3 TIMING ISSUES 278=head3 TIMING ISSUES
279 279
280There are two ways to handle timers: based on real time (relative, "fire 280There are two ways to handle timers: based on real time (relative, "fire
281in 10 seconds") and based on wallclock time (absolute, "fire at 12 281in 10 seconds") and based on wallclock time (absolute, "fire at 12
356difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 356difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
357account. 357account.
358 358
359=item AnyEvent->now_update 359=item AnyEvent->now_update
360 360
361Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache 361Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
362the current time for each loop iteration (see the discussion of L<< 362time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
363AnyEvent->now >>, above). 363above).
364 364
365When a callback runs for a long time (or when the process sleeps), then 365When a callback runs for a long time (or when the process sleeps), then
366this "current" time will differ substantially from the real time, which 366this "current" time will differ substantially from the real time, which
367might affect timers and time-outs. 367might affect timers and time-outs.
368 368
415not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's 415not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
416pure perl implementation). 416pure perl implementation).
417 417
418=head3 Safe/Unsafe Signals 418=head3 Safe/Unsafe Signals
419 419
420Perl signals can be either "safe" (synchronous to opcode handling) or 420Perl signals can be either "safe" (synchronous to opcode handling)
421"unsafe" (asynchronous) - the former might get delayed indefinitely, the 421or "unsafe" (asynchronous) - the former might delay signal delivery
422latter might corrupt your memory. 422indefinitely, the latter might corrupt your memory.
423 423
424AnyEvent signal handlers are, in addition, synchronous to the event loop, 424AnyEvent signal handlers are, in addition, synchronous to the event loop,
425i.e. they will not interrupt your running perl program but will only be 425i.e. they will not interrupt your running perl program but will only be
426called as part of the normal event handling (just like timer, I/O etc. 426called as part of the normal event handling (just like timer, I/O etc.
427callbacks, too). 427callbacks, too).
428 428
429=head3 Signal Races, Delays and Workarounds 429=head3 Signal Races, Delays and Workarounds
430 430
431Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching 431Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
432callbacks to signals in a generic way, which is a pity, as you cannot 432attaching callbacks to signals in a generic way, which is a pity,
433do race-free signal handling in perl, requiring C libraries for 433as you cannot do race-free signal handling in perl, requiring
434this. AnyEvent will try to do its best, which means in some cases, 434C libraries for this. AnyEvent will try to do its best, which
435signals will be delayed. The maximum time a signal might be delayed is 435means in some cases, signals will be delayed. The maximum time
436specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This 436a signal might be delayed is 10 seconds by default, but can
437variable can be changed only before the first signal watcher is created, 437be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
438and should be left alone otherwise. This variable determines how often 438C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
439AnyEvent polls for signals (in case a wake-up was missed). Higher values 439section for details.
440will cause fewer spurious wake-ups, which is better for power and CPU
441saving.
442 440
443All these problems can be avoided by installing the optional 441All these problems can be avoided by installing the optional
444L<Async::Interrupt> module, which works with most event loops. It will not 442L<Async::Interrupt> module, which works with most event loops. It will not
445work with inherently broken event loops such as L<Event> or L<Event::Lib> 443work with inherently broken event loops such as L<Event> or L<Event::Lib>
446(and not with L<POE> currently, as POE does its own workaround with 444(and not with L<POE> currently). For those, you just have to suffer the
447one-second latency). For those, you just have to suffer the delays. 445delays.
448 446
449=head2 CHILD PROCESS WATCHERS 447=head2 CHILD PROCESS WATCHERS
450 448
451 $w = AnyEvent->child (pid => <process id>, cb => <callback>); 449 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
452 450
482thing in an AnyEvent program, you I<have> to create at least one 480thing in an AnyEvent program, you I<have> to create at least one
483watcher before you C<fork> the child (alternatively, you can call 481watcher before you C<fork> the child (alternatively, you can call
484C<AnyEvent::detect>). 482C<AnyEvent::detect>).
485 483
486As most event loops do not support waiting for child events, they will be 484As most event loops do not support waiting for child events, they will be
487emulated by AnyEvent in most cases, in which the latency and race problems 485emulated by AnyEvent in most cases, in which case the latency and race
488mentioned in the description of signal watchers apply. 486problems mentioned in the description of signal watchers apply.
489 487
490Example: fork a process and wait for it 488Example: fork a process and wait for it
491 489
492 my $done = AnyEvent->condvar; 490 my $done = AnyEvent->condvar;
493 491
492 # this forks and immediately calls exit in the child. this
493 # normally has all sorts of bad consequences for your parent,
494 # so take this as an example only. always fork and exec,
495 # or call POSIX::_exit, in real code.
494 my $pid = fork or exit 5; 496 my $pid = fork or exit 5;
495 497
496 my $w = AnyEvent->child ( 498 my $w = AnyEvent->child (
497 pid => $pid, 499 pid => $pid,
498 cb => sub { 500 cb => sub {
747This works because for every event source (EOF on file handle), there is 749This works because for every event source (EOF on file handle), there is
748one call to C<begin>, so the condvar waits for all calls to C<end> before 750one call to C<begin>, so the condvar waits for all calls to C<end> before
749sending. 751sending.
750 752
751The ping example mentioned above is slightly more complicated, as the 753The ping example mentioned above is slightly more complicated, as the
752there are results to be passwd back, and the number of tasks that are 754there are results to be passed back, and the number of tasks that are
753begun can potentially be zero: 755begun can potentially be zero:
754 756
755 my $cv = AnyEvent->condvar; 757 my $cv = AnyEvent->condvar;
756 758
757 my %result; 759 my %result;
765 }; 767 };
766 } 768 }
767 769
768 $cv->end; 770 $cv->end;
769 771
772 ...
773
774 my $results = $cv->recv;
775
770This code fragment supposedly pings a number of hosts and calls 776This code fragment supposedly pings a number of hosts and calls
771C<send> after results for all then have have been gathered - in any 777C<send> after results for all then have have been gathered - in any
772order. To achieve this, the code issues a call to C<begin> when it starts 778order. To achieve this, the code issues a call to C<begin> when it starts
773each ping request and calls C<end> when it has received some result for 779each ping request and calls C<end> when it has received some result for
774it. Since C<begin> and C<end> only maintain a counter, the order in which 780it. Since C<begin> and C<end> only maintain a counter, the order in which
809 815
810In list context, all parameters passed to C<send> will be returned, 816In list context, all parameters passed to C<send> will be returned,
811in scalar context only the first one will be returned. 817in scalar context only the first one will be returned.
812 818
813Note that doing a blocking wait in a callback is not supported by any 819Note that doing a blocking wait in a callback is not supported by any
814event loop, that is, recursive invocation of a blocking C<< ->recv 820event loop, that is, recursive invocation of a blocking C<< ->recv >> is
815>> is not allowed, and the C<recv> call will C<croak> if such a 821not allowed and the C<recv> call will C<croak> if such a condition is
816condition is detected. This condition can be slightly loosened by using 822detected. This requirement can be dropped by relying on L<Coro::AnyEvent>
817L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from 823, which allows you to do a blocking C<< ->recv >> from any thread
818any thread that doesn't run the event loop itself. 824that doesn't run the event loop itself. L<Coro::AnyEvent> is loaded
825automatically when L<Coro> is used with L<AnyEvent>, so code does not need
826to do anything special to take advantage of that: any code that would
827normally block your program because it calls C<recv>, be executed in an
828C<async> thread instead without blocking other threads.
819 829
820Not all event models support a blocking wait - some die in that case 830Not all event models support a blocking wait - some die in that case
821(programs might want to do that to stay interactive), so I<if you are 831(programs might want to do that to stay interactive), so I<if you are
822using this from a module, never require a blocking wait>. Instead, let the 832using this from a module, never require a blocking wait>. Instead, let the
823caller decide whether the call will block or not (for example, by coupling 833caller decide whether the call will block or not (for example, by coupling
860use. If EV is not installed, then AnyEvent will fall back to its own 870use. If EV is not installed, then AnyEvent will fall back to its own
861pure-perl implementation, which is available everywhere as it comes with 871pure-perl implementation, which is available everywhere as it comes with
862AnyEvent itself. 872AnyEvent itself.
863 873
864 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 874 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
865 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 875 AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
866 876
867=item Backends that are transparently being picked up when they are used. 877=item Backends that are transparently being picked up when they are used.
868 878
869These will be used if they are already loaded when the first watcher 879These will be used if they are already loaded when the first watcher
870is created, in which case it is assumed that the application is using 880is created, in which case it is assumed that the application is using
873create watchers. Nothing special needs to be done by the main program. 883create watchers. Nothing special needs to be done by the main program.
874 884
875 AnyEvent::Impl::Event based on Event, very stable, few glitches. 885 AnyEvent::Impl::Event based on Event, very stable, few glitches.
876 AnyEvent::Impl::Glib based on Glib, slow but very stable. 886 AnyEvent::Impl::Glib based on Glib, slow but very stable.
877 AnyEvent::Impl::Tk based on Tk, very broken. 887 AnyEvent::Impl::Tk based on Tk, very broken.
888 AnyEvent::Impl::UV based on UV, innovated square wheels.
878 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 889 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
879 AnyEvent::Impl::POE based on POE, very slow, some limitations. 890 AnyEvent::Impl::POE based on POE, very slow, some limitations.
880 AnyEvent::Impl::Irssi used when running within irssi. 891 AnyEvent::Impl::Irssi used when running within irssi.
881 AnyEvent::Impl::IOAsync based on IO::Async. 892 AnyEvent::Impl::IOAsync based on IO::Async.
882 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. 893 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
883 AnyEvent::Impl::FLTK based on FLTK. 894 AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
884 895
885=item Backends with special needs. 896=item Backends with special needs.
886 897
887Qt requires the Qt::Application to be instantiated first, but will 898Qt requires the Qt::Application to be instantiated first, but will
888otherwise be picked up automatically. As long as the main program 899otherwise be picked up automatically. As long as the main program
933 944
934Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 945Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
935if necessary. You should only call this function right before you would 946if necessary. You should only call this function right before you would
936have created an AnyEvent watcher anyway, that is, as late as possible at 947have created an AnyEvent watcher anyway, that is, as late as possible at
937runtime, and not e.g. during initialisation of your module. 948runtime, and not e.g. during initialisation of your module.
949
950The effect of calling this function is as if a watcher had been created
951(specifically, actions that happen "when the first watcher is created"
952happen when calling detetc as well).
938 953
939If you need to do some initialisation before AnyEvent watchers are 954If you need to do some initialisation before AnyEvent watchers are
940created, use C<post_detect>. 955created, use C<post_detect>.
941 956
942=item $guard = AnyEvent::post_detect { BLOCK } 957=item $guard = AnyEvent::post_detect { BLOCK }
1005 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent 1020 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
1006 # as soon as it is 1021 # as soon as it is
1007 push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; 1022 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
1008 } 1023 }
1009 1024
1025=item AnyEvent::postpone { BLOCK }
1026
1027Arranges for the block to be executed as soon as possible, but not before
1028the call itself returns. In practise, the block will be executed just
1029before the event loop polls for new events, or shortly afterwards.
1030
1031This function never returns anything (to make the C<return postpone { ...
1032}> idiom more useful.
1033
1034To understand the usefulness of this function, consider a function that
1035asynchronously does something for you and returns some transaction
1036object or guard to let you cancel the operation. For example,
1037C<AnyEvent::Socket::tcp_connect>:
1038
1039 # start a connection attempt unless one is active
1040 $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
1041 delete $self->{connect_guard};
1042 ...
1043 };
1044
1045Imagine that this function could instantly call the callback, for
1046example, because it detects an obvious error such as a negative port
1047number. Invoking the callback before the function returns causes problems
1048however: the callback will be called and will try to delete the guard
1049object. But since the function hasn't returned yet, there is nothing to
1050delete. When the function eventually returns it will assign the guard
1051object to C<< $self->{connect_guard} >>, where it will likely never be
1052deleted, so the program thinks it is still trying to connect.
1053
1054This is where C<AnyEvent::postpone> should be used. Instead of calling the
1055callback directly on error:
1056
1057 $cb->(undef), return # signal error to callback, BAD!
1058 if $some_error_condition;
1059
1060It should use C<postpone>:
1061
1062 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1063 if $some_error_condition;
1064
1065=item AnyEvent::log $level, $msg[, @args]
1066
1067Log the given C<$msg> at the given C<$level>.
1068
1069If L<AnyEvent::Log> is not loaded then this function makes a simple test
1070to see whether the message will be logged. If the test succeeds it will
1071load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
1072the L<AnyEvent::Log> documentation for details.
1073
1074If the test fails it will simply return. Right now this happens when a
1075numerical loglevel is used and it is larger than the level specified via
1076C<$ENV{PERL_ANYEVENT_VERBOSE}>.
1077
1078If you want to sprinkle loads of logging calls around your code, consider
1079creating a logger callback with the C<AnyEvent::Log::logger> function,
1080which can reduce typing, codesize and can reduce the logging overhead
1081enourmously.
1082
1010=back 1083=back
1011 1084
1012=head1 WHAT TO DO IN A MODULE 1085=head1 WHAT TO DO IN A MODULE
1013 1086
1014As a module author, you should C<use AnyEvent> and call AnyEvent methods 1087As a module author, you should C<use AnyEvent> and call AnyEvent methods
1047modules might create watchers when they are loaded, and AnyEvent will 1120modules might create watchers when they are loaded, and AnyEvent will
1048decide on the event model to use as soon as it creates watchers, and it 1121decide on the event model to use as soon as it creates watchers, and it
1049might choose the wrong one unless you load the correct one yourself. 1122might choose the wrong one unless you load the correct one yourself.
1050 1123
1051You can chose to use a pure-perl implementation by loading the 1124You can chose to use a pure-perl implementation by loading the
1052C<AnyEvent::Impl::Perl> module, which gives you similar behaviour 1125C<AnyEvent::Loop> module, which gives you similar behaviour
1053everywhere, but letting AnyEvent chose the model is generally better. 1126everywhere, but letting AnyEvent chose the model is generally better.
1054 1127
1055=head2 MAINLOOP EMULATION 1128=head2 MAINLOOP EMULATION
1056 1129
1057Sometimes (often for short test scripts, or even standalone programs who 1130Sometimes (often for short test scripts, or even standalone programs who
1070 1143
1071 1144
1072=head1 OTHER MODULES 1145=head1 OTHER MODULES
1073 1146
1074The following is a non-exhaustive list of additional modules that use 1147The following is a non-exhaustive list of additional modules that use
1075AnyEvent as a client and can therefore be mixed easily with other AnyEvent 1148AnyEvent as a client and can therefore be mixed easily with other
1076modules and other event loops in the same program. Some of the modules 1149AnyEvent modules and other event loops in the same program. Some of the
1077come as part of AnyEvent, the others are available via CPAN. 1150modules come as part of AnyEvent, the others are available via CPAN (see
1151L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
1152a longer non-exhaustive list), and the list is heavily biased towards
1153modules of the AnyEvent author himself :)
1078 1154
1079=over 4 1155=over 4
1080 1156
1081=item L<AnyEvent::Util> 1157=item L<AnyEvent::Util> (part of the AnyEvent distribution)
1082 1158
1083Contains various utility functions that replace often-used blocking 1159Contains various utility functions that replace often-used blocking
1084functions such as C<inet_aton> with event/callback-based versions. 1160functions such as C<inet_aton> with event/callback-based versions.
1085 1161
1086=item L<AnyEvent::Socket> 1162=item L<AnyEvent::Socket> (part of the AnyEvent distribution)
1087 1163
1088Provides various utility functions for (internet protocol) sockets, 1164Provides various utility functions for (internet protocol) sockets,
1089addresses and name resolution. Also functions to create non-blocking tcp 1165addresses and name resolution. Also functions to create non-blocking tcp
1090connections or tcp servers, with IPv6 and SRV record support and more. 1166connections or tcp servers, with IPv6 and SRV record support and more.
1091 1167
1092=item L<AnyEvent::Handle> 1168=item L<AnyEvent::Handle> (part of the AnyEvent distribution)
1093 1169
1094Provide read and write buffers, manages watchers for reads and writes, 1170Provide read and write buffers, manages watchers for reads and writes,
1095supports raw and formatted I/O, I/O queued and fully transparent and 1171supports raw and formatted I/O, I/O queued and fully transparent and
1096non-blocking SSL/TLS (via L<AnyEvent::TLS>). 1172non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1097 1173
1098=item L<AnyEvent::DNS> 1174=item L<AnyEvent::DNS> (part of the AnyEvent distribution)
1099 1175
1100Provides rich asynchronous DNS resolver capabilities. 1176Provides rich asynchronous DNS resolver capabilities.
1101 1177
1102=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP> 1178=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
1103 1179
1104Implement event-based interfaces to the protocols of the same name (for 1180Implement event-based interfaces to the protocols of the same name (for
1105the curious, IGS is the International Go Server and FCP is the Freenet 1181the curious, IGS is the International Go Server and FCP is the Freenet
1106Client Protocol). 1182Client Protocol).
1107 1183
1108=item L<AnyEvent::Handle::UDP> 1184=item L<AnyEvent::AIO> (part of the AnyEvent distribution)
1109
1110Here be danger!
1111
1112As Pauli would put it, "Not only is it not right, it's not even wrong!" -
1113there are so many things wrong with AnyEvent::Handle::UDP, most notably
1114its use of a stream-based API with a protocol that isn't streamable, that
1115the only way to improve it is to delete it.
1116
1117It features data corruption (but typically only under load) and general
1118confusion. On top, the author is not only clueless about UDP but also
1119fact-resistant - some gems of his understanding: "connect doesn't work
1120with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
1121packets", "I don't need to implement proper error checking as UDP doesn't
1122support error checking" and so on - he doesn't even understand what's
1123wrong with his module when it is explained to him.
1124
1125=item L<AnyEvent::DBI>
1126
1127Executes L<DBI> requests asynchronously in a proxy process for you,
1128notifying you in an event-based way when the operation is finished.
1129
1130=item L<AnyEvent::AIO>
1131 1185
1132Truly asynchronous (as opposed to non-blocking) I/O, should be in the 1186Truly asynchronous (as opposed to non-blocking) I/O, should be in the
1133toolbox of every event programmer. AnyEvent::AIO transparently fuses 1187toolbox of every event programmer. AnyEvent::AIO transparently fuses
1134L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based 1188L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
1135file I/O, and much more. 1189file I/O, and much more.
1136 1190
1191=item L<AnyEvent::Fork>, L<AnyEvent::Fork::RPC>, L<AnyEvent::Fork::Pool>, L<AnyEvent::Fork::Remote>
1192
1193These let you safely fork new subprocesses, either locally or
1194remotely (e.g.v ia ssh), using some RPC protocol or not, without
1195the limitations normally imposed by fork (AnyEvent works fine for
1196example). Dynamically-resized worker pools are obviously included as well.
1197
1198And they are quite tiny and fast as well - "abusing" L<AnyEvent::Fork>
1199just to exec external programs can easily beat using C<fork> and C<exec>
1200(or even C<system>) in most programs.
1201
1202=item L<AnyEvent::Filesys::Notify>
1203
1204AnyEvent is good for non-blocking stuff, but it can't detect file or
1205path changes (e.g. "watch this directory for new files", "watch this
1206file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
1207do just that in a portbale fashion, supporting inotify on GNU/Linux and
1208some weird, without doubt broken, stuff on OS X to monitor files. It can
1209fall back to blocking scans at regular intervals transparently on other
1210platforms, so it's about as portable as it gets.
1211
1212(I haven't used it myself, but it seems the biggest problem with it is
1213it quite bad performance).
1214
1137=item L<AnyEvent::HTTPD> 1215=item L<AnyEvent::DBI>
1138 1216
1139A simple embedded webserver. 1217Executes L<DBI> requests asynchronously in a proxy process for you,
1218notifying you in an event-based way when the operation is finished.
1140 1219
1141=item L<AnyEvent::FastPing> 1220=item L<AnyEvent::FastPing>
1142 1221
1143The fastest ping in the west. 1222The fastest ping in the west.
1144 1223
1145=item L<Coro> 1224=item L<Coro>
1146 1225
1147Has special support for AnyEvent via L<Coro::AnyEvent>. 1226Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
1227to simply invert the flow control - don't call us, we will call you:
1228
1229 async {
1230 Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
1231 print "5 seconds later!\n";
1232
1233 Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
1234 my $line = <STDIN>; # works for ttys
1235
1236 AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
1237 my ($body, $hdr) = Coro::rouse_wait;
1238 };
1148 1239
1149=back 1240=back
1150 1241
1151=cut 1242=cut
1152 1243
1153package AnyEvent; 1244package AnyEvent;
1154
1155# basically a tuned-down version of common::sense
1156sub common_sense {
1157 # from common:.sense 3.4
1158 ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1159 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1160 $^H |= 0x00000600;
1161}
1162
1163BEGIN { AnyEvent::common_sense }
1164
1165use Carp ();
1166
1167our $VERSION = '5.34';
1168our $MODEL;
1169
1170our $AUTOLOAD;
1171our @ISA;
1172
1173our @REGISTRY;
1174
1175our $VERBOSE;
1176 1245
1177BEGIN { 1246BEGIN {
1178 require "AnyEvent/constants.pl"; 1247 require "AnyEvent/constants.pl";
1248 &AnyEvent::common_sense;
1249}
1179 1250
1251use Carp ();
1252
1253our $VERSION = '7.07';
1254our $MODEL;
1255our @ISA;
1256our @REGISTRY;
1257our $VERBOSE;
1258our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1259our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1260
1261BEGIN {
1180 eval "sub TAINT (){" . (${^TAINT}*1) . "}"; 1262 eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1181 1263
1182 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1264 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1183 if ${^TAINT}; 1265 if ${^TAINT};
1184 1266
1185 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1267 $ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
1268 for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1186 1269
1187} 1270 @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
1271 if ${^TAINT};
1188 1272
1189our $MAX_SIGNAL_LATENCY = 10; 1273 # $ENV{PERL_ANYEVENT_xxx} now valid
1190 1274
1191our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1275 $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1192 1276
1193{
1194 my $idx; 1277 my $idx;
1195 $PROTOCOL{$_} = ++$idx 1278 $PROTOCOL{$_} = ++$idx
1196 for reverse split /\s*,\s*/, 1279 for reverse split /\s*,\s*/,
1197 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1280 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1198} 1281}
1199 1282
1283our @post_detect;
1284
1285sub post_detect(&) {
1286 my ($cb) = @_;
1287
1288 push @post_detect, $cb;
1289
1290 defined wantarray
1291 ? bless \$cb, "AnyEvent::Util::postdetect"
1292 : ()
1293}
1294
1295sub AnyEvent::Util::postdetect::DESTROY {
1296 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1297}
1298
1299our $POSTPONE_W;
1300our @POSTPONE;
1301
1302sub _postpone_exec {
1303 undef $POSTPONE_W;
1304
1305 &{ shift @POSTPONE }
1306 while @POSTPONE;
1307}
1308
1309sub postpone(&) {
1310 push @POSTPONE, shift;
1311
1312 $POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
1313
1314 ()
1315}
1316
1317sub log($$;@) {
1318 # only load the big bloated module when we actually are about to log something
1319 if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
1320 local ($!, $@);
1321 require AnyEvent::Log; # among other things, sets $VERBOSE to 9
1322 # AnyEvent::Log overwrites this function
1323 goto &log;
1324 }
1325
1326 0 # not logged
1327}
1328
1329sub _logger($;$) {
1330 my ($level, $renabled) = @_;
1331
1332 $$renabled = $level <= $VERBOSE;
1333
1334 my $logger = [(caller)[0], $level, $renabled];
1335
1336 $AnyEvent::Log::LOGGER{$logger+0} = $logger;
1337
1338# return unless defined wantarray;
1339#
1340# require AnyEvent::Util;
1341# my $guard = AnyEvent::Util::guard (sub {
1342# # "clean up"
1343# delete $LOGGER{$logger+0};
1344# });
1345#
1346# sub {
1347# return 0 unless $$renabled;
1348#
1349# $guard if 0; # keep guard alive, but don't cause runtime overhead
1350# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
1351# package AnyEvent::Log;
1352# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
1353# }
1354}
1355
1356if (length $ENV{PERL_ANYEVENT_LOG}) {
1357 require AnyEvent::Log; # AnyEvent::Log does the thing for us
1358}
1359
1200my @models = ( 1360our @models = (
1201 [EV:: => AnyEvent::Impl::EV:: , 1], 1361 [EV:: => AnyEvent::Impl::EV::],
1202 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], 1362 [AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1203 # everything below here will not (normally) be autoprobed 1363 # everything below here will not (normally) be autoprobed
1204 # as the pureperl backend should work everywhere 1364 # as the pure perl backend should work everywhere
1205 # and is usually faster 1365 # and is usually faster
1366 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
1206 [Event:: => AnyEvent::Impl::Event::, 1], 1367 [Event:: => AnyEvent::Impl::Event::], # slow, stable
1207 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers 1368 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1369 # everything below here should not be autoloaded
1208 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1370 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1209 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1210 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1371 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1372 [UV:: => AnyEvent::Impl::UV::], # switched from libev, added back all bugs imaginable
1211 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1373 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1212 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1374 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1213 [Wx:: => AnyEvent::Impl::POE::], 1375 [Wx:: => AnyEvent::Impl::POE::],
1214 [Prima:: => AnyEvent::Impl::POE::], 1376 [Prima:: => AnyEvent::Impl::POE::],
1215 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], 1377 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1216 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::], 1378 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1217 [FLTK:: => AnyEvent::Impl::FLTK::], 1379 [FLTK:: => AnyEvent::Impl::FLTK::],
1218); 1380);
1219 1381
1220our %method = map +($_ => 1), 1382our @isa_hook;
1383
1384sub _isa_set {
1385 my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
1386
1387 @{"$pkg[$_-1]::ISA"} = $pkg[$_]
1388 for 1 .. $#pkg;
1389
1390 grep $_ && $_->[1], @isa_hook
1391 and AE::_reset ();
1392}
1393
1394# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
1395sub _isa_hook($$;$) {
1396 my ($i, $pkg, $reset_ae) = @_;
1397
1398 $isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
1399
1400 _isa_set;
1401}
1402
1403# all autoloaded methods reserve the complete glob, not just the method slot.
1404# due to bugs in perls method cache implementation.
1221 qw(io timer time now now_update signal child idle condvar DESTROY); 1405our @methods = qw(io timer time now now_update signal child idle condvar);
1222
1223our @post_detect;
1224
1225sub post_detect(&) {
1226 my ($cb) = @_;
1227
1228 push @post_detect, $cb;
1229
1230 defined wantarray
1231 ? bless \$cb, "AnyEvent::Util::postdetect"
1232 : ()
1233}
1234
1235sub AnyEvent::Util::postdetect::DESTROY {
1236 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1237}
1238 1406
1239sub detect() { 1407sub detect() {
1408 return $MODEL if $MODEL; # some programs keep references to detect
1409
1410 # IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1411 # the author knows about the problems and what it does to AnyEvent as a whole
1412 # (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
1413 # anyway.
1414 AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
1415 . "design, abuses internals and breaks AnyEvent - will not continue."
1416 if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1417
1418 local $!; # for good measure
1419 local $SIG{__DIE__}; # we use eval
1420
1240 # free some memory 1421 # free some memory
1241 *detect = sub () { $MODEL }; 1422 *detect = sub () { $MODEL };
1423 # undef &func doesn't correctly update the method cache. grmbl.
1424 # so we delete the whole glob. grmbl.
1425 # otoh, perl doesn't let me undef an active usb, but it lets me free
1426 # a glob with an active sub. hrm. i hope it works, but perl is
1427 # usually buggy in this department. sigh.
1428 delete @{"AnyEvent::"}{@methods};
1429 undef @methods;
1242 1430
1243 local $!; # for good measure
1244 local $SIG{__DIE__};
1245
1246 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1431 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
1247 my $model = "AnyEvent::Impl::$1"; 1432 my $model = $1;
1433 $model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
1248 if (eval "require $model") { 1434 if (eval "require $model") {
1435 AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
1249 $MODEL = $model; 1436 $MODEL = $model;
1250 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1251 } else { 1437 } else {
1252 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; 1438 AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1253 } 1439 }
1254 } 1440 }
1255 1441
1256 # check for already loaded models 1442 # check for already loaded models
1257 unless ($MODEL) { 1443 unless ($MODEL) {
1258 for (@REGISTRY, @models) { 1444 for (@REGISTRY, @models) {
1259 my ($package, $model) = @$_; 1445 my ($package, $model) = @$_;
1260 if (${"$package\::VERSION"} > 0) { 1446 if (${"$package\::VERSION"} > 0) {
1261 if (eval "require $model") { 1447 if (eval "require $model") {
1448 AnyEvent::log 7 => "Autodetected model '$model', using it.";
1262 $MODEL = $model; 1449 $MODEL = $model;
1263 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2; 1450 last;
1451 } else {
1452 AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
1453 }
1454 }
1455 }
1456
1457 unless ($MODEL) {
1458 # try to autoload a model
1459 for (@REGISTRY, @models) {
1460 my ($package, $model) = @$_;
1461 if (
1462 eval "require $package"
1463 and ${"$package\::VERSION"} > 0
1464 and eval "require $model"
1465 ) {
1466 AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1467 $MODEL = $model;
1264 last; 1468 last;
1265 } 1469 }
1266 } 1470 }
1267 }
1268
1269 unless ($MODEL) {
1270 # try to autoload a model
1271 for (@REGISTRY, @models) {
1272 my ($package, $model, $autoload) = @$_;
1273 if (
1274 $autoload
1275 and eval "require $package"
1276 and ${"$package\::VERSION"} > 0
1277 and eval "require $model"
1278 ) {
1279 $MODEL = $model;
1280 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1281 last;
1282 }
1283 }
1284 1471
1285 $MODEL 1472 $MODEL
1286 or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n"; 1473 or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1287 } 1474 }
1288 } 1475 }
1289 1476
1290 @models = (); # free probe data 1477 # free memory only needed for probing
1478 undef @models;
1479 undef @REGISTRY;
1291 1480
1292 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1481 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1293 unshift @ISA, $MODEL;
1294 1482
1295 # now nuke some methods that are overridden by the backend. 1483 # now nuke some methods that are overridden by the backend.
1296 # SUPER is not allowed. 1484 # SUPER usage is not allowed in these.
1297 for (qw(time signal child idle)) { 1485 for (qw(time signal child idle)) {
1298 undef &{"AnyEvent::Base::$_"} 1486 undef &{"AnyEvent::Base::$_"}
1299 if defined &{"$MODEL\::$_"}; 1487 if defined &{"$MODEL\::$_"};
1300 } 1488 }
1301 1489
1490 _isa_set;
1491
1492 # we're officially open!
1493
1302 if ($ENV{PERL_ANYEVENT_STRICT}) { 1494 if ($ENV{PERL_ANYEVENT_STRICT}) {
1303 eval { require AnyEvent::Strict }; 1495 require AnyEvent::Strict;
1304 warn "AnyEvent: cannot load AnyEvent::Strict: $@"
1305 if $@ && $VERBOSE;
1306 } 1496 }
1307 1497
1498 if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
1499 require AnyEvent::Debug;
1500 AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
1501 }
1502
1503 if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
1504 require AnyEvent::Socket;
1505 require AnyEvent::Debug;
1506
1507 my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
1508 $shell =~ s/\$\$/$$/g;
1509
1510 my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
1511 $AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
1512 }
1513
1514 # now the anyevent environment is set up as the user told us to, so
1515 # call the actual user code - post detects
1516
1308 (shift @post_detect)->() while @post_detect; 1517 (shift @post_detect)->() while @post_detect;
1518 undef @post_detect;
1309 1519
1310 *post_detect = sub(&) { 1520 *post_detect = sub(&) {
1311 shift->(); 1521 shift->();
1312 1522
1313 undef 1523 undef
1314 }; 1524 };
1315 1525
1316 $MODEL 1526 $MODEL
1317} 1527}
1318 1528
1319sub AUTOLOAD { 1529for my $name (@methods) {
1320 (my $func = $AUTOLOAD) =~ s/.*://; 1530 *$name = sub {
1321
1322 $method{$func}
1323 or Carp::croak "$func: not a valid AnyEvent class method";
1324
1325 detect; 1531 detect;
1326 1532 # we use goto because
1327 my $class = shift; 1533 # a) it makes the thunk more transparent
1328 $class->$func (@_); 1534 # b) it allows us to delete the thunk later
1535 goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1536 };
1329} 1537}
1330 1538
1331# utility function to dup a filehandle. this is used by many backends 1539# utility function to dup a filehandle. this is used by many backends
1332# to support binding more than one watcher per filehandle (they usually 1540# to support binding more than one watcher per filehandle (they usually
1333# allow only one watcher per fd, so we dup it to get a different one). 1541# allow only one watcher per fd, so we dup it to get a different one).
1357 1565
1358package AE; 1566package AE;
1359 1567
1360our $VERSION = $AnyEvent::VERSION; 1568our $VERSION = $AnyEvent::VERSION;
1361 1569
1570sub _reset() {
1571 eval q{
1362# fall back to the main API by default - backends and AnyEvent::Base 1572 # fall back to the main API by default - backends and AnyEvent::Base
1363# implementations can overwrite these. 1573 # implementations can overwrite these.
1364 1574
1365sub io($$$) { 1575 sub io($$$) {
1366 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) 1576 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1367} 1577 }
1368 1578
1369sub timer($$$) { 1579 sub timer($$$) {
1370 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]) 1580 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1371} 1581 }
1372 1582
1373sub signal($$) { 1583 sub signal($$) {
1374 AnyEvent->signal (signal => $_[0], cb => $_[1]) 1584 AnyEvent->signal (signal => $_[0], cb => $_[1])
1375} 1585 }
1376 1586
1377sub child($$) { 1587 sub child($$) {
1378 AnyEvent->child (pid => $_[0], cb => $_[1]) 1588 AnyEvent->child (pid => $_[0], cb => $_[1])
1379} 1589 }
1380 1590
1381sub idle($) { 1591 sub idle($) {
1382 AnyEvent->idle (cb => $_[0]) 1592 AnyEvent->idle (cb => $_[0]);
1383} 1593 }
1384 1594
1385sub cv(;&) { 1595 sub cv(;&) {
1386 AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) 1596 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1387} 1597 }
1388 1598
1389sub now() { 1599 sub now() {
1390 AnyEvent->now 1600 AnyEvent->now
1391} 1601 }
1392 1602
1393sub now_update() { 1603 sub now_update() {
1394 AnyEvent->now_update 1604 AnyEvent->now_update
1395} 1605 }
1396 1606
1397sub time() { 1607 sub time() {
1398 AnyEvent->time 1608 AnyEvent->time
1609 }
1610
1611 *postpone = \&AnyEvent::postpone;
1612 *log = \&AnyEvent::log;
1613 };
1614 die if $@;
1399} 1615}
1616
1617BEGIN { _reset }
1400 1618
1401package AnyEvent::Base; 1619package AnyEvent::Base;
1402 1620
1403# default implementations for many methods 1621# default implementations for many methods
1404 1622
1405sub time { 1623sub time {
1406 eval q{ # poor man's autoloading {} 1624 eval q{ # poor man's autoloading {}
1407 # probe for availability of Time::HiRes 1625 # probe for availability of Time::HiRes
1408 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1626 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1409 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1627 *time = sub { Time::HiRes::time () };
1410 *AE::time = \&Time::HiRes::time; 1628 *AE::time = \& Time::HiRes::time ;
1629 *now = \&time;
1630 AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1411 # if (eval "use POSIX (); (POSIX::times())... 1631 # if (eval "use POSIX (); (POSIX::times())...
1412 } else { 1632 } else {
1413 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; 1633 *time = sub { CORE::time };
1414 *AE::time = sub (){ time }; # epic fail 1634 *AE::time = sub (){ CORE::time };
1635 *now = \&time;
1636 AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
1415 } 1637 }
1416
1417 *time = sub { AE::time }; # different prototypes
1418 }; 1638 };
1419 die if $@; 1639 die if $@;
1420 1640
1421 &time 1641 &time
1422} 1642}
1423 1643
1424*now = \&time; 1644*now = \&time;
1425
1426sub now_update { } 1645sub now_update { }
1427 1646
1647sub _poll {
1648 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
1649}
1650
1428# default implementation for ->condvar 1651# default implementation for ->condvar
1652# in fact, the default should not be overwritten
1429 1653
1430sub condvar { 1654sub condvar {
1431 eval q{ # poor man's autoloading {} 1655 eval q{ # poor man's autoloading {}
1432 *condvar = sub { 1656 *condvar = sub {
1433 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1657 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1511 1735
1512sub signal { 1736sub signal {
1513 eval q{ # poor man's autoloading {} 1737 eval q{ # poor man's autoloading {}
1514 # probe for availability of Async::Interrupt 1738 # probe for availability of Async::Interrupt
1515 if (_have_async_interrupt) { 1739 if (_have_async_interrupt) {
1516 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8; 1740 AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1517 1741
1518 $SIGPIPE_R = new Async::Interrupt::EventPipe; 1742 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1519 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec; 1743 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1520 1744
1521 } else { 1745 } else {
1522 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8; 1746 AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1523 1747
1524 if (AnyEvent::WIN32) { 1748 if (AnyEvent::WIN32) {
1525 require AnyEvent::Util; 1749 require AnyEvent::Util;
1526 1750
1527 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); 1751 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1603 : sysread $SIGPIPE_R, (my $dummy), 9; 1827 : sysread $SIGPIPE_R, (my $dummy), 9;
1604 1828
1605 while (%SIG_EV) { 1829 while (%SIG_EV) {
1606 for (keys %SIG_EV) { 1830 for (keys %SIG_EV) {
1607 delete $SIG_EV{$_}; 1831 delete $SIG_EV{$_};
1608 $_->() for values %{ $SIG_CB{$_} || {} }; 1832 &$_ for values %{ $SIG_CB{$_} || {} };
1609 } 1833 }
1610 } 1834 }
1611 }; 1835 };
1612 }; 1836 };
1613 die if $@; 1837 die if $@;
1640 }; 1864 };
1641 1865
1642 *child = sub { 1866 *child = sub {
1643 my (undef, %arg) = @_; 1867 my (undef, %arg) = @_;
1644 1868
1645 defined (my $pid = $arg{pid} + 0) 1869 my $pid = $arg{pid};
1646 or Carp::croak "required option 'pid' is missing"; 1870 my $cb = $arg{cb};
1647 1871
1648 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1872 $PID_CB{$pid}{$cb+0} = $cb;
1649 1873
1650 unless ($CHLD_W) { 1874 unless ($CHLD_W) {
1651 $CHLD_W = AE::signal CHLD => \&_sigchld; 1875 $CHLD_W = AE::signal CHLD => \&_sigchld;
1652 # child could be a zombie already, so make at least one round 1876 # child could be a zombie already, so make at least one round
1653 &_sigchld; 1877 &_sigchld;
1654 } 1878 }
1655 1879
1656 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1880 bless [$pid, $cb+0], "AnyEvent::Base::child"
1657 }; 1881 };
1658 1882
1659 *AnyEvent::Base::child::DESTROY = sub { 1883 *AnyEvent::Base::child::DESTROY = sub {
1660 my ($pid, $cb) = @{$_[0]}; 1884 my ($pid, $icb) = @{$_[0]};
1661 1885
1662 delete $PID_CB{$pid}{$cb}; 1886 delete $PID_CB{$pid}{$icb};
1663 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1887 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1664 1888
1665 undef $CHLD_W unless keys %PID_CB; 1889 undef $CHLD_W unless keys %PID_CB;
1666 }; 1890 };
1667 }; 1891 };
1680 1904
1681 my ($cb, $w, $rcb) = $arg{cb}; 1905 my ($cb, $w, $rcb) = $arg{cb};
1682 1906
1683 $rcb = sub { 1907 $rcb = sub {
1684 if ($cb) { 1908 if ($cb) {
1685 $w = _time; 1909 $w = AE::time;
1686 &$cb; 1910 &$cb;
1687 $w = _time - $w; 1911 $w = AE::time - $w;
1688 1912
1689 # never use more then 50% of the time for the idle watcher, 1913 # never use more then 50% of the time for the idle watcher,
1690 # within some limits 1914 # within some limits
1691 $w = 0.0001 if $w < 0.0001; 1915 $w = 0.0001 if $w < 0.0001;
1692 $w = 5 if $w > 5; 1916 $w = 5 if $w > 5;
1740sub _send { 1964sub _send {
1741 # nop 1965 # nop
1742} 1966}
1743 1967
1744sub _wait { 1968sub _wait {
1745 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught"; 1969 AnyEvent->_poll until $_[0]{_ae_sent};
1746} 1970}
1747 1971
1748sub send { 1972sub send {
1749 my $cv = shift; 1973 my $cv = shift;
1750 $cv->{_ae_sent} = [@_]; 1974 $cv->{_ae_sent} = [@_];
1762} 1986}
1763 1987
1764sub recv { 1988sub recv {
1765 unless ($_[0]{_ae_sent}) { 1989 unless ($_[0]{_ae_sent}) {
1766 $WAITING 1990 $WAITING
1767 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected"; 1991 and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
1768 1992
1769 local $WAITING = 1; 1993 local $WAITING = 1;
1770 $_[0]->_wait; 1994 $_[0]->_wait;
1771 } 1995 }
1772 1996
1821$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and 2045$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1822so on. 2046so on.
1823 2047
1824=head1 ENVIRONMENT VARIABLES 2048=head1 ENVIRONMENT VARIABLES
1825 2049
1826The following environment variables are used by this module or its 2050AnyEvent supports a number of environment variables that tune the
1827submodules. 2051runtime behaviour. They are usually evaluated when AnyEvent is
2052loaded, initialised, or a submodule that uses them is loaded. Many of
2053them also cause AnyEvent to load additional modules - for example,
2054C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
2055loaded.
1828 2056
1829Note that AnyEvent will remove I<all> environment variables starting with 2057All the environment variables documented here start with
1830C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is 2058C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1831enabled. 2059namespace. Other modules are encouraged (but by no means required) to use
2060C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
2061namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
2062be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
2063variables starting with C<AE_>, see below).
2064
2065All variables can also be set via the C<AE_> prefix, that is, instead
2066of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
2067case there is a clash btween anyevent and another program that uses
2068C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
2069variable to the empty string, as those variables take precedence.
2070
2071When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
2072to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
2073exists. If taint mode is on, then AnyEvent will remove I<all> environment
2074variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
2075with C<undef> or the empty string, if the corresaponding C<AE_> variable
2076is set).
2077
2078The exact algorithm is currently:
2079
2080 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
2081 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
2082 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
2083
2084This ensures that child processes will not see the C<AE_> variables.
2085
2086The following environment variables are currently known to AnyEvent:
1832 2087
1833=over 4 2088=over 4
1834 2089
1835=item C<PERL_ANYEVENT_VERBOSE> 2090=item C<PERL_ANYEVENT_VERBOSE>
1836 2091
1837By default, AnyEvent will be completely silent except in fatal 2092By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1838conditions. You can set this environment variable to make AnyEvent more 2093higher (see L<AnyEvent::Log>). You can set this environment variable to a
1839talkative. 2094numerical loglevel to make AnyEvent more (or less) talkative.
1840 2095
2096If you want to do more than just set the global logging level
2097you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
2098complex specifications.
2099
2100When set to C<0> (C<off>), then no messages whatsoever will be logged with
2101everything else at defaults.
2102
1841When set to C<1> or higher, causes AnyEvent to warn about unexpected 2103When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1842conditions, such as not being able to load the event model specified by 2104conditions, such as not being able to load the event model specified by
1843C<PERL_ANYEVENT_MODEL>. 2105C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
2106is the minimum recommended level for use during development.
1844 2107
1845When set to C<2> or higher, cause AnyEvent to report to STDERR which event 2108When set to C<7> or higher (info), AnyEvent reports which event model it
1846model it chooses. 2109chooses.
1847 2110
1848When set to C<8> or higher, then AnyEvent will report extra information on 2111When set to C<8> or higher (debug), then AnyEvent will report extra
1849which optional modules it loads and how it implements certain features. 2112information on which optional modules it loads and how it implements
2113certain features.
2114
2115=item C<PERL_ANYEVENT_LOG>
2116
2117Accepts rather complex logging specifications. For example, you could log
2118all C<debug> messages of some module to stderr, warnings and above to
2119stderr, and errors and above to syslog, with:
2120
2121 PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
2122
2123For the rather extensive details, see L<AnyEvent::Log>.
2124
2125This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
2126so will take effect even before AnyEvent has initialised itself.
2127
2128Note that specifying this environment variable causes the L<AnyEvent::Log>
2129module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
2130using the latter saves a few hundred kB of memory unless a module
2131explicitly needs the extra features of AnyEvent::Log.
1850 2132
1851=item C<PERL_ANYEVENT_STRICT> 2133=item C<PERL_ANYEVENT_STRICT>
1852 2134
1853AnyEvent does not do much argument checking by default, as thorough 2135AnyEvent does not do much argument checking by default, as thorough
1854argument checking is very costly. Setting this variable to a true value 2136argument checking is very costly. Setting this variable to a true value
1861Unlike C<use strict> (or its modern cousin, C<< use L<common::sense> 2143Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1862>>, it is definitely recommended to keep it off in production. Keeping 2144>>, it is definitely recommended to keep it off in production. Keeping
1863C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs 2145C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1864can be very useful, however. 2146can be very useful, however.
1865 2147
2148=item C<PERL_ANYEVENT_DEBUG_SHELL>
2149
2150If this env variable is nonempty, then its contents will be interpreted by
2151C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
2152replacing every occurance of C<$$> by the process pid). The shell object
2153is saved in C<$AnyEvent::Debug::SHELL>.
2154
2155This happens when the first watcher is created.
2156
2157For example, to bind a debug shell on a unix domain socket in
2158F<< /tmp/debug<pid>.sock >>, you could use this:
2159
2160 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
2161 # connect with e.g.: socat readline /tmp/debug123.sock
2162
2163Or to bind to tcp port 4545 on localhost:
2164
2165 PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
2166 # connect with e.g.: telnet localhost 4545
2167
2168Note that creating sockets in F</tmp> or on localhost is very unsafe on
2169multiuser systems.
2170
2171=item C<PERL_ANYEVENT_DEBUG_WRAP>
2172
2173Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
2174debugging purposes. See C<AnyEvent::Debug::wrap> for details.
2175
1866=item C<PERL_ANYEVENT_MODEL> 2176=item C<PERL_ANYEVENT_MODEL>
1867 2177
1868This can be used to specify the event model to be used by AnyEvent, before 2178This can be used to specify the event model to be used by AnyEvent, before
1869auto detection and -probing kicks in. It must be a string consisting 2179auto detection and -probing kicks in.
1870entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 2180
2181It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
2182or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1871and the resulting module name is loaded and if the load was successful, 2183resulting module name is loaded and - if the load was successful - used as
1872used as event model. If it fails to load AnyEvent will proceed with 2184event model backend. If it fails to load then AnyEvent will proceed with
1873auto detection and -probing. 2185auto detection and -probing.
1874 2186
1875This functionality might change in future versions. 2187If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
2188nothing gets prepended and the module name is used as-is (hint: C<::> at
2189the end of a string designates a module name and quotes it appropriately).
1876 2190
1877For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 2191For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1878could start your program like this: 2192could start your program like this:
1879 2193
1880 PERL_ANYEVENT_MODEL=Perl perl ... 2194 PERL_ANYEVENT_MODEL=Perl perl ...
2195
2196=item C<PERL_ANYEVENT_IO_MODEL>
2197
2198The current file I/O model - see L<AnyEvent::IO> for more info.
2199
2200At the moment, only C<Perl> (small, pure-perl, synchronous) and
2201C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
2202L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1881 2203
1882=item C<PERL_ANYEVENT_PROTOCOLS> 2204=item C<PERL_ANYEVENT_PROTOCOLS>
1883 2205
1884Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences 2206Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1885for IPv4 or IPv6. The default is unspecified (and might change, or be the result 2207for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1890used, and preference will be given to protocols mentioned earlier in the 2212used, and preference will be given to protocols mentioned earlier in the
1891list. 2213list.
1892 2214
1893This variable can effectively be used for denial-of-service attacks 2215This variable can effectively be used for denial-of-service attacks
1894against local programs (e.g. when setuid), although the impact is likely 2216against local programs (e.g. when setuid), although the impact is likely
1895small, as the program has to handle conenction and other failures anyways. 2217small, as the program has to handle connection and other failures anyways.
1896 2218
1897Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, 2219Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1898but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 2220but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1899- only support IPv4, never try to resolve or contact IPv6 2221- only support IPv4, never try to resolve or contact IPv6
1900addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 2222addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1901IPv6, but prefer IPv6 over IPv4. 2223IPv6, but prefer IPv6 over IPv4.
1902 2224
2225=item C<PERL_ANYEVENT_HOSTS>
2226
2227This variable, if specified, overrides the F</etc/hosts> file used by
2228L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
2229from that file instead.
2230
1903=item C<PERL_ANYEVENT_EDNS0> 2231=item C<PERL_ANYEVENT_EDNS0>
1904 2232
1905Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension 2233Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1906for DNS. This extension is generally useful to reduce DNS traffic, but 2234DNS. This extension is generally useful to reduce DNS traffic, especially
1907some (broken) firewalls drop such DNS packets, which is why it is off by 2235when DNSSEC is involved, but some (broken) firewalls drop such DNS
1908default. 2236packets, which is why it is off by default.
1909 2237
1910Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 2238Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1911EDNS0 in its DNS requests. 2239EDNS0 in its DNS requests.
1912 2240
1913=item C<PERL_ANYEVENT_MAX_FORKS> 2241=item C<PERL_ANYEVENT_MAX_FORKS>
1919 2247
1920The default value for the C<max_outstanding> parameter for the default DNS 2248The default value for the C<max_outstanding> parameter for the default DNS
1921resolver - this is the maximum number of parallel DNS requests that are 2249resolver - this is the maximum number of parallel DNS requests that are
1922sent to the DNS server. 2250sent to the DNS server.
1923 2251
2252=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
2253
2254Perl has inherently racy signal handling (you can basically choose between
2255losing signals and memory corruption) - pure perl event loops (including
2256C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
2257have to poll regularly to avoid losing signals.
2258
2259Some event loops are racy, but don't poll regularly, and some event loops
2260are written in C but are still racy. For those event loops, AnyEvent
2261installs a timer that regularly wakes up the event loop.
2262
2263By default, the interval for this timer is C<10> seconds, but you can
2264override this delay with this environment variable (or by setting
2265the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
2266watchers).
2267
2268Lower values increase CPU (and energy) usage, higher values can introduce
2269long delays when reaping children or waiting for signals.
2270
2271The L<AnyEvent::Async> module, if available, will be used to avoid this
2272polling (with most event loops).
2273
1924=item C<PERL_ANYEVENT_RESOLV_CONF> 2274=item C<PERL_ANYEVENT_RESOLV_CONF>
1925 2275
1926The file to use instead of F</etc/resolv.conf> (or OS-specific 2276The absolute path to a F<resolv.conf>-style file to use instead of
1927configuration) in the default resolver. When set to the empty string, no 2277F</etc/resolv.conf> (or the OS-specific configuration) in the default
1928default config will be used. 2278resolver, or the empty string to select the default configuration.
1929 2279
1930=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. 2280=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1931 2281
1932When neither C<ca_file> nor C<ca_path> was specified during 2282When neither C<ca_file> nor C<ca_path> was specified during
1933L<AnyEvent::TLS> context creation, and either of these environment 2283L<AnyEvent::TLS> context creation, and either of these environment
1934variables exist, they will be used to specify CA certificate locations 2284variables are nonempty, they will be used to specify CA certificate
1935instead of a system-dependent default. 2285locations instead of a system-dependent default.
1936 2286
1937=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT> 2287=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1938 2288
1939When these are set to C<1>, then the respective modules are not 2289When these are set to C<1>, then the respective modules are not
1940loaded. Mostly good for testing AnyEvent itself. 2290loaded. Mostly good for testing AnyEvent itself.
2272(even when used without AnyEvent), but most event loops have acceptable 2622(even when used without AnyEvent), but most event loops have acceptable
2273performance with or without AnyEvent. 2623performance with or without AnyEvent.
2274 2624
2275=item * The overhead AnyEvent adds is usually much smaller than the overhead of 2625=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2276the actual event loop, only with extremely fast event loops such as EV 2626the actual event loop, only with extremely fast event loops such as EV
2277adds AnyEvent significant overhead. 2627does AnyEvent add significant overhead.
2278 2628
2279=item * You should avoid POE like the plague if you want performance or 2629=item * You should avoid POE like the plague if you want performance or
2280reasonable memory usage. 2630reasonable memory usage.
2281 2631
2282=back 2632=back
2581 2931
2582=item L<Time::HiRes> 2932=item L<Time::HiRes>
2583 2933
2584This module is part of perl since release 5.008. It will be used when the 2934This module is part of perl since release 5.008. It will be used when the
2585chosen event library does not come with a timing source of its own. The 2935chosen event library does not come with a timing source of its own. The
2586pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to 2936pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2587try to use a monotonic clock for timing stability. 2937try to use a monotonic clock for timing stability.
2938
2939=item L<AnyEvent::AIO> (and L<IO::AIO>)
2940
2941The default implementation of L<AnyEvent::IO> is to do I/O synchronously,
2942stopping programs while they access the disk, which is fine for a lot of
2943programs.
2944
2945Installing AnyEvent::AIO (and its IO::AIO dependency) makes it switch to
2946a true asynchronous implementation, so event processing can continue even
2947while waiting for disk I/O.
2588 2948
2589=back 2949=back
2590 2950
2591 2951
2592=head1 FORK 2952=head1 FORK
2604usually happens when the first AnyEvent watcher is created, or the library 2964usually happens when the first AnyEvent watcher is created, or the library
2605is loaded). 2965is loaded).
2606 2966
2607If you have to fork, you must either do so I<before> creating your first 2967If you have to fork, you must either do so I<before> creating your first
2608watcher OR you must not use AnyEvent at all in the child OR you must do 2968watcher OR you must not use AnyEvent at all in the child OR you must do
2609something completely out of the scope of AnyEvent. 2969something completely out of the scope of AnyEvent (see below).
2610 2970
2611The problem of doing event processing in the parent I<and> the child 2971The problem of doing event processing in the parent I<and> the child
2612is much more complicated: even for backends that I<are> fork-aware or 2972is much more complicated: even for backends that I<are> fork-aware or
2613fork-safe, their behaviour is not usually what you want: fork clones all 2973fork-safe, their behaviour is not usually what you want: fork clones all
2614watchers, that means all timers, I/O watchers etc. are active in both 2974watchers, that means all timers, I/O watchers etc. are active in both
2615parent and child, which is almost never what you want. USing C<exec> 2975parent and child, which is almost never what you want. Using C<exec>
2616to start worker children from some kind of manage rprocess is usually 2976to start worker children from some kind of manage prrocess is usually
2617preferred, because it is much easier and cleaner, at the expense of having 2977preferred, because it is much easier and cleaner, at the expense of having
2618to have another binary. 2978to have another binary.
2979
2980In addition to logical problems with fork, there are also implementation
2981problems. For example, on POSIX systems, you cannot fork at all in Perl
2982code if a thread (I am talking of pthreads here) was ever created in the
2983process, and this is just the tip of the iceberg. In general, using fork
2984from Perl is difficult, and attempting to use fork without an exec to
2985implement some kind of parallel processing is almost certainly doomed.
2986
2987To safely fork and exec, you should use a module such as
2988L<Proc::FastSpawn> that let's you safely fork and exec new processes.
2989
2990If you want to do multiprocessing using processes, you can
2991look at the L<AnyEvent::Fork> module (and some related modules
2992such as L<AnyEvent::Fork::RPC>, L<AnyEvent::Fork::Pool> and
2993L<AnyEvent::Fork::Remote>). This module allows you to safely create
2994subprocesses without any limitations - you can use X11 toolkits or
2995AnyEvent in the children created by L<AnyEvent::Fork> safely and without
2996any special precautions.
2619 2997
2620 2998
2621=head1 SECURITY CONSIDERATIONS 2999=head1 SECURITY CONSIDERATIONS
2622 3000
2623AnyEvent can be forced to load any event model via 3001AnyEvent can be forced to load any event model via
2657 3035
2658Tutorial/Introduction: L<AnyEvent::Intro>. 3036Tutorial/Introduction: L<AnyEvent::Intro>.
2659 3037
2660FAQ: L<AnyEvent::FAQ>. 3038FAQ: L<AnyEvent::FAQ>.
2661 3039
2662Utility functions: L<AnyEvent::Util>. 3040Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
3041(simply logging).
2663 3042
2664Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 3043Development/Debugging: L<AnyEvent::Strict> (stricter checking),
2665L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 3044L<AnyEvent::Debug> (interactive shell, watcher tracing).
3045
3046Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
3047L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
3048L<Qt>, L<POE>, L<FLTK>.
2666 3049
2667Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 3050Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2668L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 3051L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2669L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 3052L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2670L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>. 3053L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
3054L<AnyEvent::Impl::FLTK>.
2671 3055
2672Non-blocking file handles, sockets, TCP clients and 3056Non-blocking handles, pipes, stream sockets, TCP clients and
2673servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 3057servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
3058
3059Asynchronous File I/O: L<AnyEvent::IO>.
2674 3060
2675Asynchronous DNS: L<AnyEvent::DNS>. 3061Asynchronous DNS: L<AnyEvent::DNS>.
2676 3062
2677Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. 3063Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2678 3064
2681 3067
2682 3068
2683=head1 AUTHOR 3069=head1 AUTHOR
2684 3070
2685 Marc Lehmann <schmorp@schmorp.de> 3071 Marc Lehmann <schmorp@schmorp.de>
2686 http://home.schmorp.de/ 3072 http://anyevent.schmorp.de
2687 3073
2688=cut 3074=cut
2689 3075
26901 30761
2691 3077

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