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Revision 1.350 by root, Tue Aug 2 20:02:44 2011 UTC vs.
Revision 1.417 by root, Tue Dec 17 18:36:22 2013 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, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6and POE are various supported event loops/environments. 6FLTK 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
878 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 888 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
879 AnyEvent::Impl::POE based on POE, very slow, some limitations. 889 AnyEvent::Impl::POE based on POE, very slow, some limitations.
880 AnyEvent::Impl::Irssi used when running within irssi. 890 AnyEvent::Impl::Irssi used when running within irssi.
881 AnyEvent::Impl::IOAsync based on IO::Async. 891 AnyEvent::Impl::IOAsync based on IO::Async.
882 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. 892 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
883 AnyEvent::Impl::FLTK based on FLTK. 893 AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
884 894
885=item Backends with special needs. 895=item Backends with special needs.
886 896
887Qt requires the Qt::Application to be instantiated first, but will 897Qt requires the Qt::Application to be instantiated first, but will
888otherwise be picked up automatically. As long as the main program 898otherwise be picked up automatically. As long as the main program
933 943
934Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 944Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
935if necessary. You should only call this function right before you would 945if necessary. You should only call this function right before you would
936have created an AnyEvent watcher anyway, that is, as late as possible at 946have created an AnyEvent watcher anyway, that is, as late as possible at
937runtime, and not e.g. during initialisation of your module. 947runtime, and not e.g. during initialisation of your module.
948
949The effect of calling this function is as if a watcher had been created
950(specifically, actions that happen "when the first watcher is created"
951happen when calling detetc as well).
938 952
939If you need to do some initialisation before AnyEvent watchers are 953If you need to do some initialisation before AnyEvent watchers are
940created, use C<post_detect>. 954created, use C<post_detect>.
941 955
942=item $guard = AnyEvent::post_detect { BLOCK } 956=item $guard = AnyEvent::post_detect { BLOCK }
1005 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent 1019 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
1006 # as soon as it is 1020 # as soon as it is
1007 push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; 1021 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
1008 } 1022 }
1009 1023
1024=item AnyEvent::postpone { BLOCK }
1025
1026Arranges for the block to be executed as soon as possible, but not before
1027the call itself returns. In practise, the block will be executed just
1028before the event loop polls for new events, or shortly afterwards.
1029
1030This function never returns anything (to make the C<return postpone { ...
1031}> idiom more useful.
1032
1033To understand the usefulness of this function, consider a function that
1034asynchronously does something for you and returns some transaction
1035object or guard to let you cancel the operation. For example,
1036C<AnyEvent::Socket::tcp_connect>:
1037
1038 # start a conenction attempt unless one is active
1039 $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
1040 delete $self->{connect_guard};
1041 ...
1042 };
1043
1044Imagine that this function could instantly call the callback, for
1045example, because it detects an obvious error such as a negative port
1046number. Invoking the callback before the function returns causes problems
1047however: the callback will be called and will try to delete the guard
1048object. But since the function hasn't returned yet, there is nothing to
1049delete. When the function eventually returns it will assign the guard
1050object to C<< $self->{connect_guard} >>, where it will likely never be
1051deleted, so the program thinks it is still trying to connect.
1052
1053This is where C<AnyEvent::postpone> should be used. Instead of calling the
1054callback directly on error:
1055
1056 $cb->(undef), return # signal error to callback, BAD!
1057 if $some_error_condition;
1058
1059It should use C<postpone>:
1060
1061 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1062 if $some_error_condition;
1063
1064=item AnyEvent::log $level, $msg[, @args]
1065
1066Log the given C<$msg> at the given C<$level>.
1067
1068If L<AnyEvent::Log> is not loaded then this function makes a simple test
1069to see whether the message will be logged. If the test succeeds it will
1070load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
1071the L<AnyEvent::Log> documentation for details.
1072
1073If the test fails it will simply return. Right now this happens when a
1074numerical loglevel is used and it is larger than the level specified via
1075C<$ENV{PERL_ANYEVENT_VERBOSE}>.
1076
1077If you want to sprinkle loads of logging calls around your code, consider
1078creating a logger callback with the C<AnyEvent::Log::logger> function,
1079which can reduce typing, codesize and can reduce the logging overhead
1080enourmously.
1081
1010=back 1082=back
1011 1083
1012=head1 WHAT TO DO IN A MODULE 1084=head1 WHAT TO DO IN A MODULE
1013 1085
1014As a module author, you should C<use AnyEvent> and call AnyEvent methods 1086As a module author, you should C<use AnyEvent> and call AnyEvent methods
1047modules might create watchers when they are loaded, and AnyEvent will 1119modules 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 1120decide 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. 1121might choose the wrong one unless you load the correct one yourself.
1050 1122
1051You can chose to use a pure-perl implementation by loading the 1123You can chose to use a pure-perl implementation by loading the
1052C<AnyEvent::Impl::Perl> module, which gives you similar behaviour 1124C<AnyEvent::Loop> module, which gives you similar behaviour
1053everywhere, but letting AnyEvent chose the model is generally better. 1125everywhere, but letting AnyEvent chose the model is generally better.
1054 1126
1055=head2 MAINLOOP EMULATION 1127=head2 MAINLOOP EMULATION
1056 1128
1057Sometimes (often for short test scripts, or even standalone programs who 1129Sometimes (often for short test scripts, or even standalone programs who
1070 1142
1071 1143
1072=head1 OTHER MODULES 1144=head1 OTHER MODULES
1073 1145
1074The following is a non-exhaustive list of additional modules that use 1146The following is a non-exhaustive list of additional modules that use
1075AnyEvent as a client and can therefore be mixed easily with other AnyEvent 1147AnyEvent as a client and can therefore be mixed easily with other
1076modules and other event loops in the same program. Some of the modules 1148AnyEvent modules and other event loops in the same program. Some of the
1077come as part of AnyEvent, the others are available via CPAN. 1149modules come as part of AnyEvent, the others are available via CPAN (see
1150L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
1151a longer non-exhaustive list), and the list is heavily biased towards
1152modules of the AnyEvent author himself :)
1078 1153
1079=over 4 1154=over 4
1080 1155
1081=item L<AnyEvent::Util> 1156=item L<AnyEvent::Util> (part of the AnyEvent distribution)
1082 1157
1083Contains various utility functions that replace often-used blocking 1158Contains various utility functions that replace often-used blocking
1084functions such as C<inet_aton> with event/callback-based versions. 1159functions such as C<inet_aton> with event/callback-based versions.
1085 1160
1086=item L<AnyEvent::Socket> 1161=item L<AnyEvent::Socket> (part of the AnyEvent distribution)
1087 1162
1088Provides various utility functions for (internet protocol) sockets, 1163Provides various utility functions for (internet protocol) sockets,
1089addresses and name resolution. Also functions to create non-blocking tcp 1164addresses and name resolution. Also functions to create non-blocking tcp
1090connections or tcp servers, with IPv6 and SRV record support and more. 1165connections or tcp servers, with IPv6 and SRV record support and more.
1091 1166
1092=item L<AnyEvent::Handle> 1167=item L<AnyEvent::Handle> (part of the AnyEvent distribution)
1093 1168
1094Provide read and write buffers, manages watchers for reads and writes, 1169Provide read and write buffers, manages watchers for reads and writes,
1095supports raw and formatted I/O, I/O queued and fully transparent and 1170supports raw and formatted I/O, I/O queued and fully transparent and
1096non-blocking SSL/TLS (via L<AnyEvent::TLS>). 1171non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1097 1172
1098=item L<AnyEvent::DNS> 1173=item L<AnyEvent::DNS> (part of the AnyEvent distribution)
1099 1174
1100Provides rich asynchronous DNS resolver capabilities. 1175Provides rich asynchronous DNS resolver capabilities.
1101 1176
1102=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP> 1177=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
1103 1178
1104Implement event-based interfaces to the protocols of the same name (for 1179Implement event-based interfaces to the protocols of the same name (for
1105the curious, IGS is the International Go Server and FCP is the Freenet 1180the curious, IGS is the International Go Server and FCP is the Freenet
1106Client Protocol). 1181Client Protocol).
1107 1182
1108=item L<AnyEvent::Handle::UDP> 1183=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 1184
1132Truly asynchronous (as opposed to non-blocking) I/O, should be in the 1185Truly asynchronous (as opposed to non-blocking) I/O, should be in the
1133toolbox of every event programmer. AnyEvent::AIO transparently fuses 1186toolbox of every event programmer. AnyEvent::AIO transparently fuses
1134L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based 1187L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
1135file I/O, and much more. 1188file I/O, and much more.
1136 1189
1190=item L<AnyEvent::Fork>, L<AnyEvent::Fork::RPC>, L<AnyEvent::Fork::Pool>, L<AnyEvent::Fork::Remote>
1191
1192These let you safely fork new subprocesses, either locally or
1193remotely (e.g.v ia ssh), using some RPC protocol or not, without
1194the limitations normally imposed by fork (AnyEvent works fine for
1195example). Dynamically-resized worker pools are obviously included as well.
1196
1197And they are quite tiny and fast as well - "abusing" L<AnyEvent::Fork>
1198just to exec external programs can easily beat using C<fork> and C<exec>
1199(or even C<system>) in most programs.
1200
1201=item L<AnyEvent::Filesys::Notify>
1202
1203AnyEvent is good for non-blocking stuff, but it can't detect file or
1204path changes (e.g. "watch this directory for new files", "watch this
1205file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
1206do just that in a portbale fashion, supporting inotify on GNU/Linux and
1207some weird, without doubt broken, stuff on OS X to monitor files. It can
1208fall back to blocking scans at regular intervals transparently on other
1209platforms, so it's about as portable as it gets.
1210
1211(I haven't used it myself, but it seems the biggest problem with it is
1212it quite bad performance).
1213
1137=item L<AnyEvent::HTTPD> 1214=item L<AnyEvent::DBI>
1138 1215
1139A simple embedded webserver. 1216Executes L<DBI> requests asynchronously in a proxy process for you,
1217notifying you in an event-based way when the operation is finished.
1140 1218
1141=item L<AnyEvent::FastPing> 1219=item L<AnyEvent::FastPing>
1142 1220
1143The fastest ping in the west. 1221The fastest ping in the west.
1144 1222
1145=item L<Coro> 1223=item L<Coro>
1146 1224
1147Has special support for AnyEvent via L<Coro::AnyEvent>. 1225Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
1226to simply invert the flow control - don't call us, we will call you:
1227
1228 async {
1229 Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
1230 print "5 seconds later!\n";
1231
1232 Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
1233 my $line = <STDIN>; # works for ttys
1234
1235 AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
1236 my ($body, $hdr) = Coro::rouse_wait;
1237 };
1148 1238
1149=back 1239=back
1150 1240
1151=cut 1241=cut
1152 1242
1153package AnyEvent; 1243package 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 1244
1177BEGIN { 1245BEGIN {
1178 require "AnyEvent/constants.pl"; 1246 require "AnyEvent/constants.pl";
1247 &AnyEvent::common_sense;
1248}
1179 1249
1250use Carp ();
1251
1252our $VERSION = '7.07';
1253our $MODEL;
1254our @ISA;
1255our @REGISTRY;
1256our $VERBOSE;
1257our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1258our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1259
1260BEGIN {
1180 eval "sub TAINT (){" . (${^TAINT}*1) . "}"; 1261 eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1181 1262
1182 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1263 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1183 if ${^TAINT}; 1264 if ${^TAINT};
1184 1265
1185 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1266 $ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
1267 for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1186 1268
1187} 1269 @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
1270 if ${^TAINT};
1188 1271
1189our $MAX_SIGNAL_LATENCY = 10; 1272 # $ENV{PERL_ANYEVENT_xxx} now valid
1190 1273
1191our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1274 $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1192 1275
1193{
1194 my $idx; 1276 my $idx;
1195 $PROTOCOL{$_} = ++$idx 1277 $PROTOCOL{$_} = ++$idx
1196 for reverse split /\s*,\s*/, 1278 for reverse split /\s*,\s*/,
1197 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1279 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1198} 1280}
1199 1281
1282our @post_detect;
1283
1284sub post_detect(&) {
1285 my ($cb) = @_;
1286
1287 push @post_detect, $cb;
1288
1289 defined wantarray
1290 ? bless \$cb, "AnyEvent::Util::postdetect"
1291 : ()
1292}
1293
1294sub AnyEvent::Util::postdetect::DESTROY {
1295 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1296}
1297
1298our $POSTPONE_W;
1299our @POSTPONE;
1300
1301sub _postpone_exec {
1302 undef $POSTPONE_W;
1303
1304 &{ shift @POSTPONE }
1305 while @POSTPONE;
1306}
1307
1308sub postpone(&) {
1309 push @POSTPONE, shift;
1310
1311 $POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
1312
1313 ()
1314}
1315
1316sub log($$;@) {
1317 # only load the big bloated module when we actually are about to log something
1318 if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
1319 local ($!, $@);
1320 require AnyEvent::Log; # among other things, sets $VERBOSE to 9
1321 # AnyEvent::Log overwrites this function
1322 goto &log;
1323 }
1324
1325 0 # not logged
1326}
1327
1328sub _logger($;$) {
1329 my ($level, $renabled) = @_;
1330
1331 $$renabled = $level <= $VERBOSE;
1332
1333 my $logger = [(caller)[0], $level, $renabled];
1334
1335 $AnyEvent::Log::LOGGER{$logger+0} = $logger;
1336
1337# return unless defined wantarray;
1338#
1339# require AnyEvent::Util;
1340# my $guard = AnyEvent::Util::guard (sub {
1341# # "clean up"
1342# delete $LOGGER{$logger+0};
1343# });
1344#
1345# sub {
1346# return 0 unless $$renabled;
1347#
1348# $guard if 0; # keep guard alive, but don't cause runtime overhead
1349# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
1350# package AnyEvent::Log;
1351# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
1352# }
1353}
1354
1355if (length $ENV{PERL_ANYEVENT_LOG}) {
1356 require AnyEvent::Log; # AnyEvent::Log does the thing for us
1357}
1358
1200my @models = ( 1359our @models = (
1201 [EV:: => AnyEvent::Impl::EV:: , 1], 1360 [EV:: => AnyEvent::Impl::EV::],
1202 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], 1361 [AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1203 # everything below here will not (normally) be autoprobed 1362 # everything below here will not (normally) be autoprobed
1204 # as the pureperl backend should work everywhere 1363 # as the pure perl backend should work everywhere
1205 # and is usually faster 1364 # and is usually faster
1365 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
1206 [Event:: => AnyEvent::Impl::Event::, 1], 1366 [Event:: => AnyEvent::Impl::Event::], # slow, stable
1207 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers 1367 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1368 # everything below here should not be autoloaded
1208 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1369 [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 1370 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1211 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1371 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1212 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1372 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1213 [Wx:: => AnyEvent::Impl::POE::], 1373 [Wx:: => AnyEvent::Impl::POE::],
1214 [Prima:: => AnyEvent::Impl::POE::], 1374 [Prima:: => AnyEvent::Impl::POE::],
1215 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], 1375 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1216 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::], 1376 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1217 [FLTK:: => AnyEvent::Impl::FLTK::], 1377 [FLTK:: => AnyEvent::Impl::FLTK::],
1218); 1378);
1219 1379
1220our %method = map +($_ => 1), 1380our @isa_hook;
1381
1382sub _isa_set {
1383 my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
1384
1385 @{"$pkg[$_-1]::ISA"} = $pkg[$_]
1386 for 1 .. $#pkg;
1387
1388 grep $_ && $_->[1], @isa_hook
1389 and AE::_reset ();
1390}
1391
1392# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
1393sub _isa_hook($$;$) {
1394 my ($i, $pkg, $reset_ae) = @_;
1395
1396 $isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
1397
1398 _isa_set;
1399}
1400
1401# all autoloaded methods reserve the complete glob, not just the method slot.
1402# due to bugs in perls method cache implementation.
1221 qw(io timer time now now_update signal child idle condvar DESTROY); 1403our @methods = qw(io timer time now now_update signal child idle condvar);
1222
1223our @post_detect;
1224
1225sub post_detect(&) {
1226 my ($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 1404
1239sub detect() { 1405sub detect() {
1406 return $MODEL if $MODEL; # some programs keep references to detect
1407
1408 # IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1409 # the author knows about the problems and what it does to AnyEvent as a whole
1410 # (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
1411 # anyway.
1412 AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
1413 . "design, abuses internals and breaks AnyEvent - will not continue."
1414 if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1415
1416 local $!; # for good measure
1417 local $SIG{__DIE__}; # we use eval
1418
1240 # free some memory 1419 # free some memory
1241 *detect = sub () { $MODEL }; 1420 *detect = sub () { $MODEL };
1421 # undef &func doesn't correctly update the method cache. grmbl.
1422 # so we delete the whole glob. grmbl.
1423 # otoh, perl doesn't let me undef an active usb, but it lets me free
1424 # a glob with an active sub. hrm. i hope it works, but perl is
1425 # usually buggy in this department. sigh.
1426 delete @{"AnyEvent::"}{@methods};
1427 undef @methods;
1242 1428
1243 local $!; # for good measure
1244 local $SIG{__DIE__};
1245
1246 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1429 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
1247 my $model = "AnyEvent::Impl::$1"; 1430 my $model = $1;
1431 $model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
1248 if (eval "require $model") { 1432 if (eval "require $model") {
1433 AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
1249 $MODEL = $model; 1434 $MODEL = $model;
1250 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1251 } else { 1435 } else {
1252 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; 1436 AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1253 } 1437 }
1254 } 1438 }
1255 1439
1256 # check for already loaded models 1440 # check for already loaded models
1257 unless ($MODEL) { 1441 unless ($MODEL) {
1258 for (@REGISTRY, @models) { 1442 for (@REGISTRY, @models) {
1259 my ($package, $model) = @$_; 1443 my ($package, $model) = @$_;
1260 if (${"$package\::VERSION"} > 0) { 1444 if (${"$package\::VERSION"} > 0) {
1261 if (eval "require $model") { 1445 if (eval "require $model") {
1446 AnyEvent::log 7 => "Autodetected model '$model', using it.";
1262 $MODEL = $model; 1447 $MODEL = $model;
1263 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2; 1448 last;
1449 } else {
1450 AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
1451 }
1452 }
1453 }
1454
1455 unless ($MODEL) {
1456 # try to autoload a model
1457 for (@REGISTRY, @models) {
1458 my ($package, $model) = @$_;
1459 if (
1460 eval "require $package"
1461 and ${"$package\::VERSION"} > 0
1462 and eval "require $model"
1463 ) {
1464 AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1465 $MODEL = $model;
1264 last; 1466 last;
1265 } 1467 }
1266 } 1468 }
1267 }
1268
1269 unless ($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 1469
1285 $MODEL 1470 $MODEL
1286 or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n"; 1471 or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1287 } 1472 }
1288 } 1473 }
1289 1474
1290 @models = (); # free probe data 1475 # free memory only needed for probing
1476 undef @models;
1477 undef @REGISTRY;
1291 1478
1292 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1479 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1293 unshift @ISA, $MODEL;
1294 1480
1295 # now nuke some methods that are overridden by the backend. 1481 # now nuke some methods that are overridden by the backend.
1296 # SUPER is not allowed. 1482 # SUPER usage is not allowed in these.
1297 for (qw(time signal child idle)) { 1483 for (qw(time signal child idle)) {
1298 undef &{"AnyEvent::Base::$_"} 1484 undef &{"AnyEvent::Base::$_"}
1299 if defined &{"$MODEL\::$_"}; 1485 if defined &{"$MODEL\::$_"};
1300 } 1486 }
1301 1487
1488 _isa_set;
1489
1490 # we're officially open!
1491
1302 if ($ENV{PERL_ANYEVENT_STRICT}) { 1492 if ($ENV{PERL_ANYEVENT_STRICT}) {
1303 eval { require AnyEvent::Strict }; 1493 require AnyEvent::Strict;
1304 warn "AnyEvent: cannot load AnyEvent::Strict: $@"
1305 if $@ && $VERBOSE;
1306 } 1494 }
1307 1495
1496 if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
1497 require AnyEvent::Debug;
1498 AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
1499 }
1500
1501 if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
1502 require AnyEvent::Socket;
1503 require AnyEvent::Debug;
1504
1505 my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
1506 $shell =~ s/\$\$/$$/g;
1507
1508 my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
1509 $AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
1510 }
1511
1512 # now the anyevent environment is set up as the user told us to, so
1513 # call the actual user code - post detects
1514
1308 (shift @post_detect)->() while @post_detect; 1515 (shift @post_detect)->() while @post_detect;
1516 undef @post_detect;
1309 1517
1310 *post_detect = sub(&) { 1518 *post_detect = sub(&) {
1311 shift->(); 1519 shift->();
1312 1520
1313 undef 1521 undef
1314 }; 1522 };
1315 1523
1316 $MODEL 1524 $MODEL
1317} 1525}
1318 1526
1319sub AUTOLOAD { 1527for my $name (@methods) {
1320 (my $func = $AUTOLOAD) =~ s/.*://; 1528 *$name = sub {
1321
1322 $method{$func}
1323 or Carp::croak "$func: not a valid AnyEvent class method";
1324
1325 detect; 1529 detect;
1326 1530 # we use goto because
1327 my $class = shift; 1531 # a) it makes the thunk more transparent
1328 $class->$func (@_); 1532 # b) it allows us to delete the thunk later
1533 goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1534 };
1329} 1535}
1330 1536
1331# utility function to dup a filehandle. this is used by many backends 1537# utility function to dup a filehandle. this is used by many backends
1332# to support binding more than one watcher per filehandle (they usually 1538# to support binding more than one watcher per filehandle (they usually
1333# allow only one watcher per fd, so we dup it to get a different one). 1539# allow only one watcher per fd, so we dup it to get a different one).
1357 1563
1358package AE; 1564package AE;
1359 1565
1360our $VERSION = $AnyEvent::VERSION; 1566our $VERSION = $AnyEvent::VERSION;
1361 1567
1568sub _reset() {
1569 eval q{
1362# fall back to the main API by default - backends and AnyEvent::Base 1570 # fall back to the main API by default - backends and AnyEvent::Base
1363# implementations can overwrite these. 1571 # implementations can overwrite these.
1364 1572
1365sub io($$$) { 1573 sub io($$$) {
1366 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) 1574 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1367} 1575 }
1368 1576
1369sub timer($$$) { 1577 sub timer($$$) {
1370 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]) 1578 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1371} 1579 }
1372 1580
1373sub signal($$) { 1581 sub signal($$) {
1374 AnyEvent->signal (signal => $_[0], cb => $_[1]) 1582 AnyEvent->signal (signal => $_[0], cb => $_[1])
1375} 1583 }
1376 1584
1377sub child($$) { 1585 sub child($$) {
1378 AnyEvent->child (pid => $_[0], cb => $_[1]) 1586 AnyEvent->child (pid => $_[0], cb => $_[1])
1379} 1587 }
1380 1588
1381sub idle($) { 1589 sub idle($) {
1382 AnyEvent->idle (cb => $_[0]) 1590 AnyEvent->idle (cb => $_[0]);
1383} 1591 }
1384 1592
1385sub cv(;&) { 1593 sub cv(;&) {
1386 AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) 1594 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1387} 1595 }
1388 1596
1389sub now() { 1597 sub now() {
1390 AnyEvent->now 1598 AnyEvent->now
1391} 1599 }
1392 1600
1393sub now_update() { 1601 sub now_update() {
1394 AnyEvent->now_update 1602 AnyEvent->now_update
1395} 1603 }
1396 1604
1397sub time() { 1605 sub time() {
1398 AnyEvent->time 1606 AnyEvent->time
1607 }
1608
1609 *postpone = \&AnyEvent::postpone;
1610 *log = \&AnyEvent::log;
1611 };
1612 die if $@;
1399} 1613}
1614
1615BEGIN { _reset }
1400 1616
1401package AnyEvent::Base; 1617package AnyEvent::Base;
1402 1618
1403# default implementations for many methods 1619# default implementations for many methods
1404 1620
1405sub time { 1621sub time {
1406 eval q{ # poor man's autoloading {} 1622 eval q{ # poor man's autoloading {}
1407 # probe for availability of Time::HiRes 1623 # probe for availability of Time::HiRes
1408 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1624 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1409 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1625 *time = sub { Time::HiRes::time () };
1410 *AE::time = \&Time::HiRes::time; 1626 *AE::time = \& Time::HiRes::time ;
1627 *now = \&time;
1628 AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1411 # if (eval "use POSIX (); (POSIX::times())... 1629 # if (eval "use POSIX (); (POSIX::times())...
1412 } else { 1630 } else {
1413 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; 1631 *time = sub { CORE::time };
1414 *AE::time = sub (){ time }; # epic fail 1632 *AE::time = sub (){ CORE::time };
1633 *now = \&time;
1634 AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
1415 } 1635 }
1416
1417 *time = sub { AE::time }; # different prototypes
1418 }; 1636 };
1419 die if $@; 1637 die if $@;
1420 1638
1421 &time 1639 &time
1422} 1640}
1423 1641
1424*now = \&time; 1642*now = \&time;
1425
1426sub now_update { } 1643sub now_update { }
1427 1644
1645sub _poll {
1646 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
1647}
1648
1428# default implementation for ->condvar 1649# default implementation for ->condvar
1650# in fact, the default should not be overwritten
1429 1651
1430sub condvar { 1652sub condvar {
1431 eval q{ # poor man's autoloading {} 1653 eval q{ # poor man's autoloading {}
1432 *condvar = sub { 1654 *condvar = sub {
1433 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1655 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1511 1733
1512sub signal { 1734sub signal {
1513 eval q{ # poor man's autoloading {} 1735 eval q{ # poor man's autoloading {}
1514 # probe for availability of Async::Interrupt 1736 # probe for availability of Async::Interrupt
1515 if (_have_async_interrupt) { 1737 if (_have_async_interrupt) {
1516 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8; 1738 AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1517 1739
1518 $SIGPIPE_R = new Async::Interrupt::EventPipe; 1740 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1519 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec; 1741 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1520 1742
1521 } else { 1743 } else {
1522 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8; 1744 AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1523 1745
1524 if (AnyEvent::WIN32) { 1746 if (AnyEvent::WIN32) {
1525 require AnyEvent::Util; 1747 require AnyEvent::Util;
1526 1748
1527 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); 1749 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1603 : sysread $SIGPIPE_R, (my $dummy), 9; 1825 : sysread $SIGPIPE_R, (my $dummy), 9;
1604 1826
1605 while (%SIG_EV) { 1827 while (%SIG_EV) {
1606 for (keys %SIG_EV) { 1828 for (keys %SIG_EV) {
1607 delete $SIG_EV{$_}; 1829 delete $SIG_EV{$_};
1608 $_->() for values %{ $SIG_CB{$_} || {} }; 1830 &$_ for values %{ $SIG_CB{$_} || {} };
1609 } 1831 }
1610 } 1832 }
1611 }; 1833 };
1612 }; 1834 };
1613 die if $@; 1835 die if $@;
1640 }; 1862 };
1641 1863
1642 *child = sub { 1864 *child = sub {
1643 my (undef, %arg) = @_; 1865 my (undef, %arg) = @_;
1644 1866
1645 defined (my $pid = $arg{pid} + 0) 1867 my $pid = $arg{pid};
1646 or Carp::croak "required option 'pid' is missing"; 1868 my $cb = $arg{cb};
1647 1869
1648 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1870 $PID_CB{$pid}{$cb+0} = $cb;
1649 1871
1650 unless ($CHLD_W) { 1872 unless ($CHLD_W) {
1651 $CHLD_W = AE::signal CHLD => \&_sigchld; 1873 $CHLD_W = AE::signal CHLD => \&_sigchld;
1652 # child could be a zombie already, so make at least one round 1874 # child could be a zombie already, so make at least one round
1653 &_sigchld; 1875 &_sigchld;
1654 } 1876 }
1655 1877
1656 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1878 bless [$pid, $cb+0], "AnyEvent::Base::child"
1657 }; 1879 };
1658 1880
1659 *AnyEvent::Base::child::DESTROY = sub { 1881 *AnyEvent::Base::child::DESTROY = sub {
1660 my ($pid, $cb) = @{$_[0]}; 1882 my ($pid, $icb) = @{$_[0]};
1661 1883
1662 delete $PID_CB{$pid}{$cb}; 1884 delete $PID_CB{$pid}{$icb};
1663 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1885 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1664 1886
1665 undef $CHLD_W unless keys %PID_CB; 1887 undef $CHLD_W unless keys %PID_CB;
1666 }; 1888 };
1667 }; 1889 };
1680 1902
1681 my ($cb, $w, $rcb) = $arg{cb}; 1903 my ($cb, $w, $rcb) = $arg{cb};
1682 1904
1683 $rcb = sub { 1905 $rcb = sub {
1684 if ($cb) { 1906 if ($cb) {
1685 $w = _time; 1907 $w = AE::time;
1686 &$cb; 1908 &$cb;
1687 $w = _time - $w; 1909 $w = AE::time - $w;
1688 1910
1689 # never use more then 50% of the time for the idle watcher, 1911 # never use more then 50% of the time for the idle watcher,
1690 # within some limits 1912 # within some limits
1691 $w = 0.0001 if $w < 0.0001; 1913 $w = 0.0001 if $w < 0.0001;
1692 $w = 5 if $w > 5; 1914 $w = 5 if $w > 5;
1740sub _send { 1962sub _send {
1741 # nop 1963 # nop
1742} 1964}
1743 1965
1744sub _wait { 1966sub _wait {
1745 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught"; 1967 AnyEvent->_poll until $_[0]{_ae_sent};
1746} 1968}
1747 1969
1748sub send { 1970sub send {
1749 my $cv = shift; 1971 my $cv = shift;
1750 $cv->{_ae_sent} = [@_]; 1972 $cv->{_ae_sent} = [@_];
1762} 1984}
1763 1985
1764sub recv { 1986sub recv {
1765 unless ($_[0]{_ae_sent}) { 1987 unless ($_[0]{_ae_sent}) {
1766 $WAITING 1988 $WAITING
1767 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected"; 1989 and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
1768 1990
1769 local $WAITING = 1; 1991 local $WAITING = 1;
1770 $_[0]->_wait; 1992 $_[0]->_wait;
1771 } 1993 }
1772 1994
1821$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and 2043$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1822so on. 2044so on.
1823 2045
1824=head1 ENVIRONMENT VARIABLES 2046=head1 ENVIRONMENT VARIABLES
1825 2047
1826The following environment variables are used by this module or its 2048AnyEvent supports a number of environment variables that tune the
1827submodules. 2049runtime behaviour. They are usually evaluated when AnyEvent is
2050loaded, initialised, or a submodule that uses them is loaded. Many of
2051them also cause AnyEvent to load additional modules - for example,
2052C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
2053loaded.
1828 2054
1829Note that AnyEvent will remove I<all> environment variables starting with 2055All the environment variables documented here start with
1830C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is 2056C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1831enabled. 2057namespace. Other modules are encouraged (but by no means required) to use
2058C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
2059namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
2060be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
2061variables starting with C<AE_>, see below).
2062
2063All variables can also be set via the C<AE_> prefix, that is, instead
2064of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
2065case there is a clash btween anyevent and another program that uses
2066C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
2067variable to the empty string, as those variables take precedence.
2068
2069When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
2070to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
2071exists. If taint mode is on, then AnyEvent will remove I<all> environment
2072variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
2073with C<undef> or the empty string, if the corresaponding C<AE_> variable
2074is set).
2075
2076The exact algorithm is currently:
2077
2078 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
2079 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
2080 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
2081
2082This ensures that child processes will not see the C<AE_> variables.
2083
2084The following environment variables are currently known to AnyEvent:
1832 2085
1833=over 4 2086=over 4
1834 2087
1835=item C<PERL_ANYEVENT_VERBOSE> 2088=item C<PERL_ANYEVENT_VERBOSE>
1836 2089
1837By default, AnyEvent will be completely silent except in fatal 2090By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1838conditions. You can set this environment variable to make AnyEvent more 2091higher (see L<AnyEvent::Log>). You can set this environment variable to a
1839talkative. 2092numerical loglevel to make AnyEvent more (or less) talkative.
1840 2093
2094If you want to do more than just set the global logging level
2095you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
2096complex specifications.
2097
2098When set to C<0> (C<off>), then no messages whatsoever will be logged with
2099everything else at defaults.
2100
1841When set to C<1> or higher, causes AnyEvent to warn about unexpected 2101When 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 2102conditions, such as not being able to load the event model specified by
1843C<PERL_ANYEVENT_MODEL>. 2103C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
2104is the minimum recommended level for use during development.
1844 2105
1845When set to C<2> or higher, cause AnyEvent to report to STDERR which event 2106When set to C<7> or higher (info), AnyEvent reports which event model it
1846model it chooses. 2107chooses.
1847 2108
1848When set to C<8> or higher, then AnyEvent will report extra information on 2109When set to C<8> or higher (debug), then AnyEvent will report extra
1849which optional modules it loads and how it implements certain features. 2110information on which optional modules it loads and how it implements
2111certain features.
2112
2113=item C<PERL_ANYEVENT_LOG>
2114
2115Accepts rather complex logging specifications. For example, you could log
2116all C<debug> messages of some module to stderr, warnings and above to
2117stderr, and errors and above to syslog, with:
2118
2119 PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
2120
2121For the rather extensive details, see L<AnyEvent::Log>.
2122
2123This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
2124so will take effect even before AnyEvent has initialised itself.
2125
2126Note that specifying this environment variable causes the L<AnyEvent::Log>
2127module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
2128using the latter saves a few hundred kB of memory unless a module
2129explicitly needs the extra features of AnyEvent::Log.
1850 2130
1851=item C<PERL_ANYEVENT_STRICT> 2131=item C<PERL_ANYEVENT_STRICT>
1852 2132
1853AnyEvent does not do much argument checking by default, as thorough 2133AnyEvent does not do much argument checking by default, as thorough
1854argument checking is very costly. Setting this variable to a true value 2134argument checking is very costly. Setting this variable to a true value
1861Unlike C<use strict> (or its modern cousin, C<< use L<common::sense> 2141Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1862>>, it is definitely recommended to keep it off in production. Keeping 2142>>, it is definitely recommended to keep it off in production. Keeping
1863C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs 2143C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1864can be very useful, however. 2144can be very useful, however.
1865 2145
2146=item C<PERL_ANYEVENT_DEBUG_SHELL>
2147
2148If this env variable is nonempty, then its contents will be interpreted by
2149C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
2150replacing every occurance of C<$$> by the process pid). The shell object
2151is saved in C<$AnyEvent::Debug::SHELL>.
2152
2153This happens when the first watcher is created.
2154
2155For example, to bind a debug shell on a unix domain socket in
2156F<< /tmp/debug<pid>.sock >>, you could use this:
2157
2158 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
2159 # connect with e.g.: socat readline /tmp/debug123.sock
2160
2161Or to bind to tcp port 4545 on localhost:
2162
2163 PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
2164 # connect with e.g.: telnet localhost 4545
2165
2166Note that creating sockets in F</tmp> or on localhost is very unsafe on
2167multiuser systems.
2168
2169=item C<PERL_ANYEVENT_DEBUG_WRAP>
2170
2171Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
2172debugging purposes. See C<AnyEvent::Debug::wrap> for details.
2173
1866=item C<PERL_ANYEVENT_MODEL> 2174=item C<PERL_ANYEVENT_MODEL>
1867 2175
1868This can be used to specify the event model to be used by AnyEvent, before 2176This 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 2177auto detection and -probing kicks in.
1870entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 2178
2179It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
2180or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1871and the resulting module name is loaded and if the load was successful, 2181resulting 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 2182event model backend. If it fails to load then AnyEvent will proceed with
1873auto detection and -probing. 2183auto detection and -probing.
1874 2184
1875This functionality might change in future versions. 2185If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
2186nothing gets prepended and the module name is used as-is (hint: C<::> at
2187the end of a string designates a module name and quotes it appropriately).
1876 2188
1877For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 2189For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1878could start your program like this: 2190could start your program like this:
1879 2191
1880 PERL_ANYEVENT_MODEL=Perl perl ... 2192 PERL_ANYEVENT_MODEL=Perl perl ...
2193
2194=item C<PERL_ANYEVENT_IO_MODEL>
2195
2196The current file I/O model - see L<AnyEvent::IO> for more info.
2197
2198At the moment, only C<Perl> (small, pure-perl, synchronous) and
2199C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
2200L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1881 2201
1882=item C<PERL_ANYEVENT_PROTOCOLS> 2202=item C<PERL_ANYEVENT_PROTOCOLS>
1883 2203
1884Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences 2204Used 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 2205for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1898but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 2218but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1899- only support IPv4, never try to resolve or contact IPv6 2219- only support IPv4, never try to resolve or contact IPv6
1900addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 2220addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1901IPv6, but prefer IPv6 over IPv4. 2221IPv6, but prefer IPv6 over IPv4.
1902 2222
2223=item C<PERL_ANYEVENT_HOSTS>
2224
2225This variable, if specified, overrides the F</etc/hosts> file used by
2226L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
2227from that file instead.
2228
1903=item C<PERL_ANYEVENT_EDNS0> 2229=item C<PERL_ANYEVENT_EDNS0>
1904 2230
1905Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension 2231Used 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 2232DNS. This extension is generally useful to reduce DNS traffic, especially
1907some (broken) firewalls drop such DNS packets, which is why it is off by 2233when DNSSEC is involved, but some (broken) firewalls drop such DNS
1908default. 2234packets, which is why it is off by default.
1909 2235
1910Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 2236Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1911EDNS0 in its DNS requests. 2237EDNS0 in its DNS requests.
1912 2238
1913=item C<PERL_ANYEVENT_MAX_FORKS> 2239=item C<PERL_ANYEVENT_MAX_FORKS>
1919 2245
1920The default value for the C<max_outstanding> parameter for the default DNS 2246The default value for the C<max_outstanding> parameter for the default DNS
1921resolver - this is the maximum number of parallel DNS requests that are 2247resolver - this is the maximum number of parallel DNS requests that are
1922sent to the DNS server. 2248sent to the DNS server.
1923 2249
2250=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
2251
2252Perl has inherently racy signal handling (you can basically choose between
2253losing signals and memory corruption) - pure perl event loops (including
2254C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
2255have to poll regularly to avoid losing signals.
2256
2257Some event loops are racy, but don't poll regularly, and some event loops
2258are written in C but are still racy. For those event loops, AnyEvent
2259installs a timer that regularly wakes up the event loop.
2260
2261By default, the interval for this timer is C<10> seconds, but you can
2262override this delay with this environment variable (or by setting
2263the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
2264watchers).
2265
2266Lower values increase CPU (and energy) usage, higher values can introduce
2267long delays when reaping children or waiting for signals.
2268
2269The L<AnyEvent::Async> module, if available, will be used to avoid this
2270polling (with most event loops).
2271
1924=item C<PERL_ANYEVENT_RESOLV_CONF> 2272=item C<PERL_ANYEVENT_RESOLV_CONF>
1925 2273
1926The file to use instead of F</etc/resolv.conf> (or OS-specific 2274The 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 2275F</etc/resolv.conf> (or the OS-specific configuration) in the default
1928default config will be used. 2276resolver, or the empty string to select the default configuration.
1929 2277
1930=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. 2278=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1931 2279
1932When neither C<ca_file> nor C<ca_path> was specified during 2280When neither C<ca_file> nor C<ca_path> was specified during
1933L<AnyEvent::TLS> context creation, and either of these environment 2281L<AnyEvent::TLS> context creation, and either of these environment
1934variables exist, they will be used to specify CA certificate locations 2282variables are nonempty, they will be used to specify CA certificate
1935instead of a system-dependent default. 2283locations instead of a system-dependent default.
1936 2284
1937=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT> 2285=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1938 2286
1939When these are set to C<1>, then the respective modules are not 2287When these are set to C<1>, then the respective modules are not
1940loaded. Mostly good for testing AnyEvent itself. 2288loaded. Mostly good for testing AnyEvent itself.
2272(even when used without AnyEvent), but most event loops have acceptable 2620(even when used without AnyEvent), but most event loops have acceptable
2273performance with or without AnyEvent. 2621performance with or without AnyEvent.
2274 2622
2275=item * The overhead AnyEvent adds is usually much smaller than the overhead of 2623=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 2624the actual event loop, only with extremely fast event loops such as EV
2277adds AnyEvent significant overhead. 2625does AnyEvent add significant overhead.
2278 2626
2279=item * You should avoid POE like the plague if you want performance or 2627=item * You should avoid POE like the plague if you want performance or
2280reasonable memory usage. 2628reasonable memory usage.
2281 2629
2282=back 2630=back
2581 2929
2582=item L<Time::HiRes> 2930=item L<Time::HiRes>
2583 2931
2584This module is part of perl since release 5.008. It will be used when the 2932This 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 2933chosen 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 2934pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2587try to use a monotonic clock for timing stability. 2935try to use a monotonic clock for timing stability.
2936
2937=item L<AnyEvent::AIO> (and L<IO::AIO>)
2938
2939The default implementation of L<AnyEvent::IO> is to do I/O synchronously,
2940stopping programs while they access the disk, which is fine for a lot of
2941programs.
2942
2943Installing AnyEvent::AIO (and its IO::AIO dependency) makes it switch to
2944a true asynchronous implementation, so event processing can continue even
2945while waiting for disk I/O.
2588 2946
2589=back 2947=back
2590 2948
2591 2949
2592=head1 FORK 2950=head1 FORK
2604usually happens when the first AnyEvent watcher is created, or the library 2962usually happens when the first AnyEvent watcher is created, or the library
2605is loaded). 2963is loaded).
2606 2964
2607If you have to fork, you must either do so I<before> creating your first 2965If 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 2966watcher OR you must not use AnyEvent at all in the child OR you must do
2609something completely out of the scope of AnyEvent. 2967something completely out of the scope of AnyEvent (see below).
2610 2968
2611The problem of doing event processing in the parent I<and> the child 2969The 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 2970is 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 2971fork-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 2972watchers, 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> 2973parent and child, which is almost never what you want. Using C<exec>
2616to start worker children from some kind of manage rprocess is usually 2974to start worker children from some kind of manage prrocess is usually
2617preferred, because it is much easier and cleaner, at the expense of having 2975preferred, because it is much easier and cleaner, at the expense of having
2618to have another binary. 2976to have another binary.
2977
2978In addition to logical problems with fork, there are also implementation
2979problems. For example, on POSIX systems, you cannot fork at all in Perl
2980code if a thread (I am talking of pthreads here) was ever created in the
2981process, and this is just the tip of the iceberg. In general, using fork
2982from Perl is difficult, and attempting to use fork without an exec to
2983implement some kind of parallel processing is almost certainly doomed.
2984
2985To safely fork and exec, you should use a module such as
2986L<Proc::FastSpawn> that let's you safely fork and exec new processes.
2987
2988If you want to do multiprocessing using processes, you can
2989look at the L<AnyEvent::Fork> module (and some related modules
2990such as L<AnyEvent::Fork::RPC>, L<AnyEvent::Fork::Pool> and
2991L<AnyEvent::Fork::Remote>). This module allows you to safely create
2992subprocesses without any limitations - you can use X11 toolkits or
2993AnyEvent in the children created by L<AnyEvent::Fork> safely and without
2994any special precautions.
2619 2995
2620 2996
2621=head1 SECURITY CONSIDERATIONS 2997=head1 SECURITY CONSIDERATIONS
2622 2998
2623AnyEvent can be forced to load any event model via 2999AnyEvent can be forced to load any event model via
2657 3033
2658Tutorial/Introduction: L<AnyEvent::Intro>. 3034Tutorial/Introduction: L<AnyEvent::Intro>.
2659 3035
2660FAQ: L<AnyEvent::FAQ>. 3036FAQ: L<AnyEvent::FAQ>.
2661 3037
2662Utility functions: L<AnyEvent::Util>. 3038Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
3039(simply logging).
2663 3040
2664Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 3041Development/Debugging: L<AnyEvent::Strict> (stricter checking),
2665L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 3042L<AnyEvent::Debug> (interactive shell, watcher tracing).
3043
3044Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
3045L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
3046L<Qt>, L<POE>, L<FLTK>.
2666 3047
2667Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 3048Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2668L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 3049L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2669L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 3050L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2670L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>. 3051L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
3052L<AnyEvent::Impl::FLTK>.
2671 3053
2672Non-blocking file handles, sockets, TCP clients and 3054Non-blocking handles, pipes, stream sockets, TCP clients and
2673servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 3055servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
3056
3057Asynchronous File I/O: L<AnyEvent::IO>.
2674 3058
2675Asynchronous DNS: L<AnyEvent::DNS>. 3059Asynchronous DNS: L<AnyEvent::DNS>.
2676 3060
2677Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. 3061Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2678 3062
2681 3065
2682 3066
2683=head1 AUTHOR 3067=head1 AUTHOR
2684 3068
2685 Marc Lehmann <schmorp@schmorp.de> 3069 Marc Lehmann <schmorp@schmorp.de>
2686 http://home.schmorp.de/ 3070 http://anyevent.schmorp.de
2687 3071
2688=cut 3072=cut
2689 3073
26901 30741
2691 3075

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