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Revision 1.251 by root, Mon Jul 20 22:39:57 2009 UTC vs.
Revision 1.302 by root, Fri Dec 4 16:31:57 2009 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - events independent of event loop implementation 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported 5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6event loops. 6and 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
47 47
48There is a mailinglist for discussing all things AnyEvent, and an IRC 48There is a mailinglist for discussing all things AnyEvent, and an IRC
49channel, too. 49channel, too.
50 50
51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software 51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52Respository>, at L<http://anyevent.schmorp.de>, for more info. 52Repository>, at L<http://anyevent.schmorp.de>, for more info.
53 53
54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
55 55
56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
57nowadays. So what is different about AnyEvent? 57nowadays. So what is different about AnyEvent?
181my variables are only visible after the statement in which they are 181my variables are only visible after the statement in which they are
182declared. 182declared.
183 183
184=head2 I/O WATCHERS 184=head2 I/O WATCHERS
185 185
186 $w = AnyEvent->io (
187 fh => <filehandle_or_fileno>,
188 poll => <"r" or "w">,
189 cb => <callback>,
190 );
191
186You can create an I/O watcher by calling the C<< AnyEvent->io >> method 192You can create an I/O watcher by calling the C<< AnyEvent->io >> method
187with the following mandatory key-value pairs as arguments: 193with the following mandatory key-value pairs as arguments:
188 194
189C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch 195C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
190for events (AnyEvent might or might not keep a reference to this file 196for events (AnyEvent might or might not keep a reference to this file
219 undef $w; 225 undef $w;
220 }); 226 });
221 227
222=head2 TIME WATCHERS 228=head2 TIME WATCHERS
223 229
230 $w = AnyEvent->timer (after => <seconds>, cb => <callback>);
231
232 $w = AnyEvent->timer (
233 after => <fractional_seconds>,
234 interval => <fractional_seconds>,
235 cb => <callback>,
236 );
237
224You can create a time watcher by calling the C<< AnyEvent->timer >> 238You can create a time watcher by calling the C<< AnyEvent->timer >>
225method with the following mandatory arguments: 239method with the following mandatory arguments:
226 240
227C<after> specifies after how many seconds (fractional values are 241C<after> specifies after how many seconds (fractional values are
228supported) the callback should be invoked. C<cb> is the callback to invoke 242supported) the callback should be invoked. C<cb> is the callback to invoke
349might affect timers and time-outs. 363might affect timers and time-outs.
350 364
351When this is the case, you can call this method, which will update the 365When this is the case, you can call this method, which will update the
352event loop's idea of "current time". 366event loop's idea of "current time".
353 367
368A typical example would be a script in a web server (e.g. C<mod_perl>) -
369when mod_perl executes the script, then the event loop will have the wrong
370idea about the "current time" (being potentially far in the past, when the
371script ran the last time). In that case you should arrange a call to C<<
372AnyEvent->now_update >> each time the web server process wakes up again
373(e.g. at the start of your script, or in a handler).
374
354Note that updating the time I<might> cause some events to be handled. 375Note that updating the time I<might> cause some events to be handled.
355 376
356=back 377=back
357 378
358=head2 SIGNAL WATCHERS 379=head2 SIGNAL WATCHERS
380
381 $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
359 382
360You can watch for signals using a signal watcher, C<signal> is the signal 383You can watch for signals using a signal watcher, C<signal> is the signal
361I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl 384I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
362callback to be invoked whenever a signal occurs. 385callback to be invoked whenever a signal occurs.
363 386
380 403
381Example: exit on SIGINT 404Example: exit on SIGINT
382 405
383 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 406 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384 407
408=head3 Restart Behaviour
409
410While restart behaviour is up to the event loop implementation, most will
411not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
412pure perl implementation).
413
414=head3 Safe/Unsafe Signals
415
416Perl signals can be either "safe" (synchronous to opcode handling) or
417"unsafe" (asynchronous) - the former might get delayed indefinitely, the
418latter might corrupt your memory.
419
420AnyEvent signal handlers are, in addition, synchronous to the event loop,
421i.e. they will not interrupt your running perl program but will only be
422called as part of the normal event handling (just like timer, I/O etc.
423callbacks, too).
424
385=head3 Signal Races, Delays and Workarounds 425=head3 Signal Races, Delays and Workarounds
386 426
387Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching 427Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
388callbacks to signals in a generic way, which is a pity, as you cannot do 428callbacks to signals in a generic way, which is a pity, as you cannot
389race-free signal handling in perl. AnyEvent will try to do it's best, but 429do race-free signal handling in perl, requiring C libraries for
430this. AnyEvent will try to do it's best, which means in some cases,
390in some cases, signals will be delayed. The maximum time a signal might 431signals will be delayed. The maximum time a signal might be delayed is
391be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 432specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
392seconds). This variable can be changed only before the first signal 433variable can be changed only before the first signal watcher is created,
393watcher is created, and should be left alone otherwise. Higher values 434and should be left alone otherwise. This variable determines how often
435AnyEvent polls for signals (in case a wake-up was missed). Higher values
394will cause fewer spurious wake-ups, which is better for power and CPU 436will cause fewer spurious wake-ups, which is better for power and CPU
437saving.
438
395saving. All these problems can be avoided by installing the optional 439All these problems can be avoided by installing the optional
396L<Async::Interrupt> module. This will not work with inherently broken 440L<Async::Interrupt> module, which works with most event loops. It will not
397event loops such as L<Event> or L<Event::Lib> (and not with L<POE> 441work with inherently broken event loops such as L<Event> or L<Event::Lib>
398currently, as POE does it's own workaround with one-second latency). With 442(and not with L<POE> currently, as POE does it's own workaround with
399those, you just have to suffer the delays. 443one-second latency). For those, you just have to suffer the delays.
400 444
401=head2 CHILD PROCESS WATCHERS 445=head2 CHILD PROCESS WATCHERS
402 446
447 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
448
403You can also watch on a child process exit and catch its exit status. 449You can also watch on a child process exit and catch its exit status.
404 450
405The child process is specified by the C<pid> argument (if set to C<0>, it 451The child process is specified by the C<pid> argument (one some backends,
406watches for any child process exit). The watcher will triggered only when 452using C<0> watches for any child process exit, on others this will
407the child process has finished and an exit status is available, not on 453croak). The watcher will be triggered only when the child process has
408any trace events (stopped/continued). 454finished and an exit status is available, not on any trace events
455(stopped/continued).
409 456
410The callback will be called with the pid and exit status (as returned by 457The callback will be called with the pid and exit status (as returned by
411waitpid), so unlike other watcher types, you I<can> rely on child watcher 458waitpid), so unlike other watcher types, you I<can> rely on child watcher
412callback arguments. 459callback arguments.
413 460
454 # do something else, then wait for process exit 501 # do something else, then wait for process exit
455 $done->recv; 502 $done->recv;
456 503
457=head2 IDLE WATCHERS 504=head2 IDLE WATCHERS
458 505
506 $w = AnyEvent->idle (cb => <callback>);
507
459Sometimes there is a need to do something, but it is not so important 508Sometimes there is a need to do something, but it is not so important
460to do it instantly, but only when there is nothing better to do. This 509to do it instantly, but only when there is nothing better to do. This
461"nothing better to do" is usually defined to be "no other events need 510"nothing better to do" is usually defined to be "no other events need
462attention by the event loop". 511attention by the event loop".
463 512
489 }); 538 });
490 }); 539 });
491 540
492=head2 CONDITION VARIABLES 541=head2 CONDITION VARIABLES
493 542
543 $cv = AnyEvent->condvar;
544
545 $cv->send (<list>);
546 my @res = $cv->recv;
547
494If you are familiar with some event loops you will know that all of them 548If you are familiar with some event loops you will know that all of them
495require you to run some blocking "loop", "run" or similar function that 549require you to run some blocking "loop", "run" or similar function that
496will actively watch for new events and call your callbacks. 550will actively watch for new events and call your callbacks.
497 551
498AnyEvent is slightly different: it expects somebody else to run the event 552AnyEvent is slightly different: it expects somebody else to run the event
562 after => 1, 616 after => 1,
563 cb => sub { $result_ready->send }, 617 cb => sub { $result_ready->send },
564 ); 618 );
565 619
566 # this "blocks" (while handling events) till the callback 620 # this "blocks" (while handling events) till the callback
567 # calls -<send 621 # calls ->send
568 $result_ready->recv; 622 $result_ready->recv;
569 623
570Example: wait for a timer, but take advantage of the fact that condition 624Example: wait for a timer, but take advantage of the fact that condition
571variables are also callable directly. 625variables are also callable directly.
572 626
636one. For example, a function that pings many hosts in parallel might want 690one. For example, a function that pings many hosts in parallel might want
637to use a condition variable for the whole process. 691to use a condition variable for the whole process.
638 692
639Every call to C<< ->begin >> will increment a counter, and every call to 693Every call to C<< ->begin >> will increment a counter, and every call to
640C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 694C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
641>>, the (last) callback passed to C<begin> will be executed. That callback 695>>, the (last) callback passed to C<begin> will be executed, passing the
642is I<supposed> to call C<< ->send >>, but that is not required. If no 696condvar as first argument. That callback is I<supposed> to call C<< ->send
643callback was set, C<send> will be called without any arguments. 697>>, but that is not required. If no group callback was set, C<send> will
698be called without any arguments.
644 699
645You can think of C<< $cv->send >> giving you an OR condition (one call 700You can think of C<< $cv->send >> giving you an OR condition (one call
646sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND 701sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
647condition (all C<begin> calls must be C<end>'ed before the condvar sends). 702condition (all C<begin> calls must be C<end>'ed before the condvar sends).
648 703
675begung can potentially be zero: 730begung can potentially be zero:
676 731
677 my $cv = AnyEvent->condvar; 732 my $cv = AnyEvent->condvar;
678 733
679 my %result; 734 my %result;
680 $cv->begin (sub { $cv->send (\%result) }); 735 $cv->begin (sub { shift->send (\%result) });
681 736
682 for my $host (@list_of_hosts) { 737 for my $host (@list_of_hosts) {
683 $cv->begin; 738 $cv->begin;
684 ping_host_then_call_callback $host, sub { 739 ping_host_then_call_callback $host, sub {
685 $result{$host} = ...; 740 $result{$host} = ...;
760=item $cb = $cv->cb ($cb->($cv)) 815=item $cb = $cv->cb ($cb->($cv))
761 816
762This is a mutator function that returns the callback set and optionally 817This is a mutator function that returns the callback set and optionally
763replaces it before doing so. 818replaces it before doing so.
764 819
765The callback will be called when the condition becomes "true", i.e. when 820The callback will be called when the condition becomes (or already was)
766C<send> or C<croak> are called, with the only argument being the condition 821"true", i.e. when C<send> or C<croak> are called (or were called), with
767variable itself. Calling C<recv> inside the callback or at any later time 822the only argument being the condition variable itself. Calling C<recv>
768is guaranteed not to block. 823inside the callback or at any later time is guaranteed not to block.
769 824
770=back 825=back
771 826
772=head1 SUPPORTED EVENT LOOPS/BACKENDS 827=head1 SUPPORTED EVENT LOOPS/BACKENDS
773 828
776=over 4 831=over 4
777 832
778=item Backends that are autoprobed when no other event loop can be found. 833=item Backends that are autoprobed when no other event loop can be found.
779 834
780EV is the preferred backend when no other event loop seems to be in 835EV is the preferred backend when no other event loop seems to be in
781use. If EV is not installed, then AnyEvent will try Event, and, failing 836use. If EV is not installed, then AnyEvent will fall back to its own
782that, will fall back to its own pure-perl implementation, which is 837pure-perl implementation, which is available everywhere as it comes with
783available everywhere as it comes with AnyEvent itself. 838AnyEvent itself.
784 839
785 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 840 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
786 AnyEvent::Impl::Event based on Event, very stable, few glitches.
787 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 841 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
788 842
789=item Backends that are transparently being picked up when they are used. 843=item Backends that are transparently being picked up when they are used.
790 844
791These will be used when they are currently loaded when the first watcher 845These will be used when they are currently loaded when the first watcher
792is created, in which case it is assumed that the application is using 846is created, in which case it is assumed that the application is using
793them. This means that AnyEvent will automatically pick the right backend 847them. This means that AnyEvent will automatically pick the right backend
794when the main program loads an event module before anything starts to 848when the main program loads an event module before anything starts to
795create watchers. Nothing special needs to be done by the main program. 849create watchers. Nothing special needs to be done by the main program.
796 850
851 AnyEvent::Impl::Event based on Event, very stable, few glitches.
797 AnyEvent::Impl::Glib based on Glib, slow but very stable. 852 AnyEvent::Impl::Glib based on Glib, slow but very stable.
798 AnyEvent::Impl::Tk based on Tk, very broken. 853 AnyEvent::Impl::Tk based on Tk, very broken.
799 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 854 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
800 AnyEvent::Impl::POE based on POE, very slow, some limitations. 855 AnyEvent::Impl::POE based on POE, very slow, some limitations.
856 AnyEvent::Impl::Irssi used when running within irssi.
801 857
802=item Backends with special needs. 858=item Backends with special needs.
803 859
804Qt requires the Qt::Application to be instantiated first, but will 860Qt requires the Qt::Application to be instantiated first, but will
805otherwise be picked up automatically. As long as the main program 861otherwise be picked up automatically. As long as the main program
879event module detection too early, for example, L<AnyEvent::AIO> creates 935event module detection too early, for example, L<AnyEvent::AIO> creates
880and installs the global L<IO::AIO> watcher in a C<post_detect> block to 936and installs the global L<IO::AIO> watcher in a C<post_detect> block to
881avoid autodetecting the event module at load time. 937avoid autodetecting the event module at load time.
882 938
883If called in scalar or list context, then it creates and returns an object 939If called in scalar or list context, then it creates and returns an object
884that automatically removes the callback again when it is destroyed. See 940that automatically removes the callback again when it is destroyed (or
941C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
885L<Coro::BDB> for a case where this is useful. 942a case where this is useful.
943
944Example: Create a watcher for the IO::AIO module and store it in
945C<$WATCHER>. Only do so after the event loop is initialised, though.
946
947 our WATCHER;
948
949 my $guard = AnyEvent::post_detect {
950 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
951 };
952
953 # the ||= is important in case post_detect immediately runs the block,
954 # as to not clobber the newly-created watcher. assigning both watcher and
955 # post_detect guard to the same variable has the advantage of users being
956 # able to just C<undef $WATCHER> if the watcher causes them grief.
957
958 $WATCHER ||= $guard;
886 959
887=item @AnyEvent::post_detect 960=item @AnyEvent::post_detect
888 961
889If there are any code references in this array (you can C<push> to it 962If there are any code references in this array (you can C<push> to it
890before or after loading AnyEvent), then they will called directly after 963before or after loading AnyEvent), then they will called directly after
1057 1130
1058package AnyEvent; 1131package AnyEvent;
1059 1132
1060# basically a tuned-down version of common::sense 1133# basically a tuned-down version of common::sense
1061sub common_sense { 1134sub common_sense {
1062 # no warnings 1135 # from common:.sense 1.0
1063 ${^WARNING_BITS} ^= ${^WARNING_BITS}; 1136 ${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";
1064 # use strict vars subs 1137 # use strict vars subs
1065 $^H |= 0x00000600; 1138 $^H |= 0x00000600;
1066} 1139}
1067 1140
1068BEGIN { AnyEvent::common_sense } 1141BEGIN { AnyEvent::common_sense }
1069 1142
1070use Carp (); 1143use Carp ();
1071 1144
1072our $VERSION = 4.86; 1145our $VERSION = '5.21';
1073our $MODEL; 1146our $MODEL;
1074 1147
1075our $AUTOLOAD; 1148our $AUTOLOAD;
1076our @ISA; 1149our @ISA;
1077 1150
1078our @REGISTRY; 1151our @REGISTRY;
1079
1080our $WIN32;
1081 1152
1082our $VERBOSE; 1153our $VERBOSE;
1083 1154
1084BEGIN { 1155BEGIN {
1085 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1156 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
1102 for reverse split /\s*,\s*/, 1173 for reverse split /\s*,\s*/,
1103 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1174 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1104} 1175}
1105 1176
1106my @models = ( 1177my @models = (
1107 [EV:: => AnyEvent::Impl::EV::], 1178 [EV:: => AnyEvent::Impl::EV:: , 1],
1108 [Event:: => AnyEvent::Impl::Event::],
1109 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1179 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1110 # everything below here will not be autoprobed 1180 # everything below here will not (normally) be autoprobed
1111 # as the pureperl backend should work everywhere 1181 # as the pureperl backend should work everywhere
1112 # and is usually faster 1182 # and is usually faster
1183 [Event:: => AnyEvent::Impl::Event::, 1],
1113 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1184 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1114 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1185 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1186 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1115 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1187 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1116 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1188 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1117 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1189 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1118 [Wx:: => AnyEvent::Impl::POE::], 1190 [Wx:: => AnyEvent::Impl::POE::],
1119 [Prima:: => AnyEvent::Impl::POE::], 1191 [Prima:: => AnyEvent::Impl::POE::],
1120 # IO::Async is just too broken - we would need workarounds for its 1192 # IO::Async is just too broken - we would need workarounds for its
1121 # byzantine signal and broken child handling, among others. 1193 # byzantine signal and broken child handling, among others.
1122 # IO::Async is rather hard to detect, as it doesn't have any 1194 # IO::Async is rather hard to detect, as it doesn't have any
1123 # obvious default class. 1195 # obvious default class.
1124# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1196 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1125# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1197 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1126# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program 1198 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1199 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1127); 1200);
1128 1201
1129our %method = map +($_ => 1), 1202our %method = map +($_ => 1),
1130 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1203 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1131 1204
1135 my ($cb) = @_; 1208 my ($cb) = @_;
1136 1209
1137 if ($MODEL) { 1210 if ($MODEL) {
1138 $cb->(); 1211 $cb->();
1139 1212
1140 1 1213 undef
1141 } else { 1214 } else {
1142 push @post_detect, $cb; 1215 push @post_detect, $cb;
1143 1216
1144 defined wantarray 1217 defined wantarray
1145 ? bless \$cb, "AnyEvent::Util::postdetect" 1218 ? bless \$cb, "AnyEvent::Util::postdetect"
1177 } 1250 }
1178 } 1251 }
1179 } 1252 }
1180 1253
1181 unless ($MODEL) { 1254 unless ($MODEL) {
1182 # try to load a model 1255 # try to autoload a model
1183
1184 for (@REGISTRY, @models) { 1256 for (@REGISTRY, @models) {
1185 my ($package, $model) = @$_; 1257 my ($package, $model, $autoload) = @$_;
1258 if (
1259 $autoload
1186 if (eval "require $package" 1260 and eval "require $package"
1187 and ${"$package\::VERSION"} > 0 1261 and ${"$package\::VERSION"} > 0
1188 and eval "require $model") { 1262 and eval "require $model"
1263 ) {
1189 $MODEL = $model; 1264 $MODEL = $model;
1190 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2; 1265 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1191 last; 1266 last;
1192 } 1267 }
1193 } 1268 }
1194 1269
1195 $MODEL 1270 $MODEL
1236 # we assume CLOEXEC is already set by perl in all important cases 1311 # we assume CLOEXEC is already set by perl in all important cases
1237 1312
1238 ($fh2, $rw) 1313 ($fh2, $rw)
1239} 1314}
1240 1315
1316=head1 SIMPLIFIED AE API
1317
1318Starting with version 5.0, AnyEvent officially supports a second, much
1319simpler, API that is designed to reduce the calling, typing and memory
1320overhead.
1321
1322See the L<AE> manpage for details.
1323
1324=cut
1325
1326package AE;
1327
1328our $VERSION = $AnyEvent::VERSION;
1329
1330sub io($$$) {
1331 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1332}
1333
1334sub timer($$$) {
1335 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1336}
1337
1338sub signal($$) {
1339 AnyEvent->signal (signal => $_[0], cb => $_[1])
1340}
1341
1342sub child($$) {
1343 AnyEvent->child (pid => $_[0], cb => $_[1])
1344}
1345
1346sub idle($) {
1347 AnyEvent->idle (cb => $_[0])
1348}
1349
1350sub cv(;&) {
1351 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1352}
1353
1354sub now() {
1355 AnyEvent->now
1356}
1357
1358sub now_update() {
1359 AnyEvent->now_update
1360}
1361
1362sub time() {
1363 AnyEvent->time
1364}
1365
1241package AnyEvent::Base; 1366package AnyEvent::Base;
1242 1367
1243# default implementations for many methods 1368# default implementations for many methods
1244 1369
1245sub _time { 1370sub _time() {
1246 # probe for availability of Time::HiRes 1371 # probe for availability of Time::HiRes
1247 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1372 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1248 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1373 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1249 *_time = \&Time::HiRes::time; 1374 *_time = \&Time::HiRes::time;
1250 # if (eval "use POSIX (); (POSIX::times())... 1375 # if (eval "use POSIX (); (POSIX::times())...
1267} 1392}
1268 1393
1269# default implementation for ->signal 1394# default implementation for ->signal
1270 1395
1271our $HAVE_ASYNC_INTERRUPT; 1396our $HAVE_ASYNC_INTERRUPT;
1397
1398sub _have_async_interrupt() {
1399 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1400 && eval "use Async::Interrupt 1.02 (); 1")
1401 unless defined $HAVE_ASYNC_INTERRUPT;
1402
1403 $HAVE_ASYNC_INTERRUPT
1404}
1405
1272our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1406our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1273our (%SIG_ASY, %SIG_ASY_W); 1407our (%SIG_ASY, %SIG_ASY_W);
1274our ($SIG_COUNT, $SIG_TW); 1408our ($SIG_COUNT, $SIG_TW);
1275 1409
1276sub _signal_exec { 1410sub _signal_exec {
1277 $HAVE_ASYNC_INTERRUPT 1411 $HAVE_ASYNC_INTERRUPT
1278 ? $SIGPIPE_R->drain 1412 ? $SIGPIPE_R->drain
1279 : sysread $SIGPIPE_R, my $dummy, 9; 1413 : sysread $SIGPIPE_R, (my $dummy), 9;
1280 1414
1281 while (%SIG_EV) { 1415 while (%SIG_EV) {
1282 for (keys %SIG_EV) { 1416 for (keys %SIG_EV) {
1283 delete $SIG_EV{$_}; 1417 delete $SIG_EV{$_};
1284 $_->() for values %{ $SIG_CB{$_} || {} }; 1418 $_->() for values %{ $SIG_CB{$_} || {} };
1285 } 1419 }
1286 } 1420 }
1287} 1421}
1288 1422
1289# install a dumym wakeupw atcher to reduce signal catching latency 1423# install a dummy wakeup watcher to reduce signal catching latency
1290sub _sig_add() { 1424sub _sig_add() {
1291 unless ($SIG_COUNT++) { 1425 unless ($SIG_COUNT++) {
1292 # try to align timer on a full-second boundary, if possible 1426 # try to align timer on a full-second boundary, if possible
1293 my $NOW = AnyEvent->now; 1427 my $NOW = AE::now;
1294 1428
1295 $SIG_TW = AnyEvent->timer ( 1429 $SIG_TW = AE::timer
1296 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW), 1430 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1297 interval => $MAX_SIGNAL_LATENCY, 1431 $MAX_SIGNAL_LATENCY,
1298 cb => sub { }, # just for the PERL_ASYNC_CHECK 1432 sub { } # just for the PERL_ASYNC_CHECK
1299 ); 1433 ;
1300 } 1434 }
1301} 1435}
1302 1436
1303sub _sig_del { 1437sub _sig_del {
1304 undef $SIG_TW 1438 undef $SIG_TW
1305 unless --$SIG_COUNT; 1439 unless --$SIG_COUNT;
1306} 1440}
1307 1441
1442our $_sig_name_init; $_sig_name_init = sub {
1443 eval q{ # poor man's autoloading
1444 undef $_sig_name_init;
1445
1446 if (_have_async_interrupt) {
1447 *sig2num = \&Async::Interrupt::sig2num;
1448 *sig2name = \&Async::Interrupt::sig2name;
1449 } else {
1450 require Config;
1451
1452 my %signame2num;
1453 @signame2num{ split ' ', $Config::Config{sig_name} }
1454 = split ' ', $Config::Config{sig_num};
1455
1456 my @signum2name;
1457 @signum2name[values %signame2num] = keys %signame2num;
1458
1459 *sig2num = sub($) {
1460 $_[0] > 0 ? shift : $signame2num{+shift}
1461 };
1462 *sig2name = sub ($) {
1463 $_[0] > 0 ? $signum2name[+shift] : shift
1464 };
1465 }
1466 };
1467 die if $@;
1468};
1469
1470sub sig2num ($) { &$_sig_name_init; &sig2num }
1471sub sig2name($) { &$_sig_name_init; &sig2name }
1472
1308sub _signal { 1473sub signal {
1474 eval q{ # poor man's autoloading {}
1475 # probe for availability of Async::Interrupt
1476 if (_have_async_interrupt) {
1477 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1478
1479 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1480 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1481
1482 } else {
1483 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1484
1485 require Fcntl;
1486
1487 if (AnyEvent::WIN32) {
1488 require AnyEvent::Util;
1489
1490 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1491 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1492 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1493 } else {
1494 pipe $SIGPIPE_R, $SIGPIPE_W;
1495 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1496 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1497
1498 # not strictly required, as $^F is normally 2, but let's make sure...
1499 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1500 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1501 }
1502
1503 $SIGPIPE_R
1504 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1505
1506 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1507 }
1508
1509 *signal = sub {
1309 my (undef, %arg) = @_; 1510 my (undef, %arg) = @_;
1310 1511
1311 my $signal = uc $arg{signal} 1512 my $signal = uc $arg{signal}
1312 or Carp::croak "required option 'signal' is missing"; 1513 or Carp::croak "required option 'signal' is missing";
1313 1514
1314 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1315
1316 if ($HAVE_ASYNC_INTERRUPT) { 1515 if ($HAVE_ASYNC_INTERRUPT) {
1317 # async::interrupt 1516 # async::interrupt
1318 1517
1319 $SIG_ASY{$signal} ||= do { 1518 $signal = sig2num $signal;
1320 my $asy = new Async::Interrupt 1519 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1520
1521 $SIG_ASY{$signal} ||= new Async::Interrupt
1321 cb => sub { undef $SIG_EV{$signal} }, 1522 cb => sub { undef $SIG_EV{$signal} },
1322 signal => $signal, 1523 signal => $signal,
1323 pipe => [$SIGPIPE_R->filenos], 1524 pipe => [$SIGPIPE_R->filenos],
1525 pipe_autodrain => 0,
1526 ;
1527
1528 } else {
1529 # pure perl
1530
1531 # AE::Util has been loaded in signal
1532 $signal = sig2name $signal;
1533 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1534
1535 $SIG{$signal} ||= sub {
1536 local $!;
1537 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1538 undef $SIG_EV{$signal};
1539 };
1540
1541 # can't do signal processing without introducing races in pure perl,
1542 # so limit the signal latency.
1543 _sig_add;
1324 ; 1544 }
1325 $asy->pipe_autodrain (0);
1326 1545
1327 $asy 1546 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1328 }; 1547 };
1329 1548
1330 } else { 1549 *AnyEvent::Base::signal::DESTROY = sub {
1331 # pure perl 1550 my ($signal, $cb) = @{$_[0]};
1332 1551
1333 $SIG{$signal} ||= sub { 1552 _sig_del;
1334 local $!; 1553
1335 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1554 delete $SIG_CB{$signal}{$cb};
1555
1556 $HAVE_ASYNC_INTERRUPT
1557 ? delete $SIG_ASY{$signal}
1558 : # delete doesn't work with older perls - they then
1559 # print weird messages, or just unconditionally exit
1560 # instead of getting the default action.
1336 undef $SIG_EV{$signal}; 1561 undef $SIG{$signal}
1562 unless keys %{ $SIG_CB{$signal} };
1337 }; 1563 };
1338
1339 # can't do signal processing without introducing races in pure perl,
1340 # so limit the signal latency.
1341 _sig_add;
1342 } 1564 };
1343 1565 die if $@;
1344 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1345}
1346
1347sub signal {
1348 # probe for availability of Async::Interrupt
1349 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1350 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1351
1352 $HAVE_ASYNC_INTERRUPT = 1;
1353 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1354 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1355
1356 } else {
1357 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1358
1359 require Fcntl;
1360
1361 if (AnyEvent::WIN32) {
1362 require AnyEvent::Util;
1363
1364 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1365 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1366 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1367 } else {
1368 pipe $SIGPIPE_R, $SIGPIPE_W;
1369 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1370 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1371
1372 # not strictly required, as $^F is normally 2, but let's make sure...
1373 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1374 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1375 }
1376
1377 $SIGPIPE_R
1378 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1379
1380 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1381 }
1382
1383 *signal = \&_signal;
1384 &signal 1566 &signal
1385}
1386
1387sub AnyEvent::Base::signal::DESTROY {
1388 my ($signal, $cb) = @{$_[0]};
1389
1390 _sig_del;
1391
1392 delete $SIG_CB{$signal}{$cb};
1393
1394 $HAVE_ASYNC_INTERRUPT
1395 ? delete $SIG_ASY{$signal}
1396 : # delete doesn't work with older perls - they then
1397 # print weird messages, or just unconditionally exit
1398 # instead of getting the default action.
1399 undef $SIG{$signal}
1400 unless keys %{ $SIG_CB{$signal} };
1401} 1567}
1402 1568
1403# default implementation for ->child 1569# default implementation for ->child
1404 1570
1405our %PID_CB; 1571our %PID_CB;
1406our $CHLD_W; 1572our $CHLD_W;
1407our $CHLD_DELAY_W; 1573our $CHLD_DELAY_W;
1408our $WNOHANG; 1574our $WNOHANG;
1409 1575
1576sub _emit_childstatus($$) {
1577 my (undef, $rpid, $rstatus) = @_;
1578
1579 $_->($rpid, $rstatus)
1580 for values %{ $PID_CB{$rpid} || {} },
1581 values %{ $PID_CB{0} || {} };
1582}
1583
1410sub _sigchld { 1584sub _sigchld {
1585 my $pid;
1586
1587 AnyEvent->_emit_childstatus ($pid, $?)
1411 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1588 while ($pid = waitpid -1, $WNOHANG) > 0;
1412 $_->($pid, $?)
1413 for values %{ $PID_CB{$pid} || {} },
1414 values %{ $PID_CB{0} || {} };
1415 }
1416} 1589}
1417 1590
1418sub child { 1591sub child {
1419 my (undef, %arg) = @_; 1592 my (undef, %arg) = @_;
1420 1593
1427 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/ 1600 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1428 ? 1 1601 ? 1
1429 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1602 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1430 1603
1431 unless ($CHLD_W) { 1604 unless ($CHLD_W) {
1432 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1605 $CHLD_W = AE::signal CHLD => \&_sigchld;
1433 # child could be a zombie already, so make at least one round 1606 # child could be a zombie already, so make at least one round
1434 &_sigchld; 1607 &_sigchld;
1435 } 1608 }
1436 1609
1437 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1610 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1463 # never use more then 50% of the time for the idle watcher, 1636 # never use more then 50% of the time for the idle watcher,
1464 # within some limits 1637 # within some limits
1465 $w = 0.0001 if $w < 0.0001; 1638 $w = 0.0001 if $w < 0.0001;
1466 $w = 5 if $w > 5; 1639 $w = 5 if $w > 5;
1467 1640
1468 $w = AnyEvent->timer (after => $w, cb => $rcb); 1641 $w = AE::timer $w, 0, $rcb;
1469 } else { 1642 } else {
1470 # clean up... 1643 # clean up...
1471 undef $w; 1644 undef $w;
1472 undef $rcb; 1645 undef $rcb;
1473 } 1646 }
1474 }; 1647 };
1475 1648
1476 $w = AnyEvent->timer (after => 0.05, cb => $rcb); 1649 $w = AE::timer 0.05, 0, $rcb;
1477 1650
1478 bless \\$cb, "AnyEvent::Base::idle" 1651 bless \\$cb, "AnyEvent::Base::idle"
1479} 1652}
1480 1653
1481sub AnyEvent::Base::idle::DESTROY { 1654sub AnyEvent::Base::idle::DESTROY {
1535 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1708 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1536 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1709 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1537} 1710}
1538 1711
1539sub cb { 1712sub cb {
1540 $_[0]{_ae_cb} = $_[1] if @_ > 1; 1713 my $cv = shift;
1714
1715 @_
1716 and $cv->{_ae_cb} = shift
1717 and $cv->{_ae_sent}
1718 and (delete $cv->{_ae_cb})->($cv);
1719
1541 $_[0]{_ae_cb} 1720 $cv->{_ae_cb}
1542} 1721}
1543 1722
1544sub begin { 1723sub begin {
1545 ++$_[0]{_ae_counter}; 1724 ++$_[0]{_ae_counter};
1546 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1725 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1755 warn "read: $input\n"; # output what has been read 1934 warn "read: $input\n"; # output what has been read
1756 $cv->send if $input =~ /^q/i; # quit program if /^q/i 1935 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1757 }, 1936 },
1758 ); 1937 );
1759 1938
1760 my $time_watcher; # can only be used once
1761
1762 sub new_timer {
1763 $timer = AnyEvent->timer (after => 1, cb => sub { 1939 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1764 warn "timeout\n"; # print 'timeout' about every second 1940 warn "timeout\n"; # print 'timeout' at most every second
1765 &new_timer; # and restart the time
1766 }); 1941 });
1767 }
1768
1769 new_timer; # create first timer
1770 1942
1771 $cv->recv; # wait until user enters /^q/i 1943 $cv->recv; # wait until user enters /^q/i
1772 1944
1773=head1 REAL-WORLD EXAMPLE 1945=head1 REAL-WORLD EXAMPLE
1774 1946
1905through AnyEvent. The benchmark creates a lot of timers (with a zero 2077through AnyEvent. The benchmark creates a lot of timers (with a zero
1906timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2078timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1907which it is), lets them fire exactly once and destroys them again. 2079which it is), lets them fire exactly once and destroys them again.
1908 2080
1909Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2081Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1910distribution. 2082distribution. It uses the L<AE> interface, which makes a real difference
2083for the EV and Perl backends only.
1911 2084
1912=head3 Explanation of the columns 2085=head3 Explanation of the columns
1913 2086
1914I<watcher> is the number of event watchers created/destroyed. Since 2087I<watcher> is the number of event watchers created/destroyed. Since
1915different event models feature vastly different performances, each event 2088different event models feature vastly different performances, each event
1936watcher. 2109watcher.
1937 2110
1938=head3 Results 2111=head3 Results
1939 2112
1940 name watchers bytes create invoke destroy comment 2113 name watchers bytes create invoke destroy comment
1941 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2114 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1942 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2115 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1943 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2116 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1944 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2117 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1945 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2118 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1946 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2119 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1947 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll 2120 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1948 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll 2121 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1949 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2122 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1950 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2123 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1951 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2124 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1952 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2125 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1953 2126
1954=head3 Discussion 2127=head3 Discussion
1955 2128
1956The benchmark does I<not> measure scalability of the event loop very 2129The benchmark does I<not> measure scalability of the event loop very
1957well. For example, a select-based event loop (such as the pure perl one) 2130well. For example, a select-based event loop (such as the pure perl one)
1969benchmark machine, handling an event takes roughly 1600 CPU cycles with 2142benchmark machine, handling an event takes roughly 1600 CPU cycles with
1970EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2143EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1971cycles with POE. 2144cycles with POE.
1972 2145
1973C<EV> is the sole leader regarding speed and memory use, which are both 2146C<EV> is the sole leader regarding speed and memory use, which are both
1974maximal/minimal, respectively. Even when going through AnyEvent, it uses 2147maximal/minimal, respectively. When using the L<AE> API there is zero
2148overhead (when going through the AnyEvent API create is about 5-6 times
2149slower, with other times being equal, so still uses far less memory than
1975far less memory than any other event loop and is still faster than Event 2150any other event loop and is still faster than Event natively).
1976natively.
1977 2151
1978The pure perl implementation is hit in a few sweet spots (both the 2152The pure perl implementation is hit in a few sweet spots (both the
1979constant timeout and the use of a single fd hit optimisations in the perl 2153constant timeout and the use of a single fd hit optimisations in the perl
1980interpreter and the backend itself). Nevertheless this shows that it 2154interpreter and the backend itself). Nevertheless this shows that it
1981adds very little overhead in itself. Like any select-based backend its 2155adds very little overhead in itself. Like any select-based backend its
2055In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2229In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2056(1%) are active. This mirrors the activity of large servers with many 2230(1%) are active. This mirrors the activity of large servers with many
2057connections, most of which are idle at any one point in time. 2231connections, most of which are idle at any one point in time.
2058 2232
2059Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2233Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2060distribution. 2234distribution. It uses the L<AE> interface, which makes a real difference
2235for the EV and Perl backends only.
2061 2236
2062=head3 Explanation of the columns 2237=head3 Explanation of the columns
2063 2238
2064I<sockets> is the number of sockets, and twice the number of "servers" (as 2239I<sockets> is the number of sockets, and twice the number of "servers" (as
2065each server has a read and write socket end). 2240each server has a read and write socket end).
2073a new one that moves the timeout into the future. 2248a new one that moves the timeout into the future.
2074 2249
2075=head3 Results 2250=head3 Results
2076 2251
2077 name sockets create request 2252 name sockets create request
2078 EV 20000 69.01 11.16 2253 EV 20000 62.66 7.99
2079 Perl 20000 73.32 35.87 2254 Perl 20000 68.32 32.64
2080 IOAsync 20000 157.00 98.14 epoll 2255 IOAsync 20000 174.06 101.15 epoll
2081 IOAsync 20000 159.31 616.06 poll 2256 IOAsync 20000 174.67 610.84 poll
2082 Event 20000 212.62 257.32 2257 Event 20000 202.69 242.91
2083 Glib 20000 651.16 1896.30 2258 Glib 20000 557.01 1689.52
2084 POE 20000 349.67 12317.24 uses POE::Loop::Event 2259 POE 20000 341.54 12086.32 uses POE::Loop::Event
2085 2260
2086=head3 Discussion 2261=head3 Discussion
2087 2262
2088This benchmark I<does> measure scalability and overall performance of the 2263This benchmark I<does> measure scalability and overall performance of the
2089particular event loop. 2264particular event loop.
2215As you can see, the AnyEvent + EV combination even beats the 2390As you can see, the AnyEvent + EV combination even beats the
2216hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl 2391hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2217backend easily beats IO::Lambda and POE. 2392backend easily beats IO::Lambda and POE.
2218 2393
2219And even the 100% non-blocking version written using the high-level (and 2394And even the 100% non-blocking version written using the high-level (and
2220slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a 2395slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2221large margin, even though it does all of DNS, tcp-connect and socket I/O 2396higher level ("unoptimised") abstractions by a large margin, even though
2222in a non-blocking way. 2397it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2223 2398
2224The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and 2399The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2225F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are 2400F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2226part of the IO::lambda distribution and were used without any changes. 2401part of the IO::Lambda distribution and were used without any changes.
2227 2402
2228 2403
2229=head1 SIGNALS 2404=head1 SIGNALS
2230 2405
2231AnyEvent currently installs handlers for these signals: 2406AnyEvent currently installs handlers for these signals:
2273it's built-in modules) are required to use it. 2448it's built-in modules) are required to use it.
2274 2449
2275That does not mean that AnyEvent won't take advantage of some additional 2450That does not mean that AnyEvent won't take advantage of some additional
2276modules if they are installed. 2451modules if they are installed.
2277 2452
2278This section epxlains which additional modules will be used, and how they 2453This section explains which additional modules will be used, and how they
2279affect AnyEvent's operetion. 2454affect AnyEvent's operation.
2280 2455
2281=over 4 2456=over 4
2282 2457
2283=item L<Async::Interrupt> 2458=item L<Async::Interrupt>
2284 2459
2289catch the signals) with some delay (default is 10 seconds, look for 2464catch the signals) with some delay (default is 10 seconds, look for
2290C<$AnyEvent::MAX_SIGNAL_LATENCY>). 2465C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2291 2466
2292If this module is available, then it will be used to implement signal 2467If this module is available, then it will be used to implement signal
2293catching, which means that signals will not be delayed, and the event loop 2468catching, which means that signals will not be delayed, and the event loop
2294will not be interrupted regularly, which is more efficient (And good for 2469will not be interrupted regularly, which is more efficient (and good for
2295battery life on laptops). 2470battery life on laptops).
2296 2471
2297This affects not just the pure-perl event loop, but also other event loops 2472This affects not just the pure-perl event loop, but also other event loops
2298that have no signal handling on their own (e.g. Glib, Tk, Qt). 2473that have no signal handling on their own (e.g. Glib, Tk, Qt).
2299 2474
2320lot less memory), but otherwise doesn't affect guard operation much. It is 2495lot less memory), but otherwise doesn't affect guard operation much. It is
2321purely used for performance. 2496purely used for performance.
2322 2497
2323=item L<JSON> and L<JSON::XS> 2498=item L<JSON> and L<JSON::XS>
2324 2499
2325This module is required when you want to read or write JSON data via 2500One of these modules is required when you want to read or write JSON data
2326L<AnyEvent::Handle>. It is also written in pure-perl, but can take 2501via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2327advantage of the ultra-high-speed L<JSON::XS> module when it is installed. 2502advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2328 2503
2329In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is 2504In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2330installed. 2505installed.
2331 2506
2349 2524
2350Most event libraries are not fork-safe. The ones who are usually are 2525Most event libraries are not fork-safe. The ones who are usually are
2351because they rely on inefficient but fork-safe C<select> or C<poll> 2526because they rely on inefficient but fork-safe C<select> or C<poll>
2352calls. Only L<EV> is fully fork-aware. 2527calls. Only L<EV> is fully fork-aware.
2353 2528
2529This means that, in general, you cannot fork and do event processing
2530in the child if a watcher was created before the fork (which in turn
2531initialises the event library).
2532
2354If you have to fork, you must either do so I<before> creating your first 2533If you have to fork, you must either do so I<before> creating your first
2355watcher OR you must not use AnyEvent at all in the child OR you must do 2534watcher OR you must not use AnyEvent at all in the child OR you must do
2356something completely out of the scope of AnyEvent. 2535something completely out of the scope of AnyEvent.
2536
2537The problem of doing event processing in the parent I<and> the child
2538is much more complicated: even for backends that I<are> fork-aware or
2539fork-safe, their behaviour is not usually what you want: fork clones all
2540watchers, that means all timers, I/O watchers etc. are active in both
2541parent and child, which is almost never what you want.
2357 2542
2358 2543
2359=head1 SECURITY CONSIDERATIONS 2544=head1 SECURITY CONSIDERATIONS
2360 2545
2361AnyEvent can be forced to load any event model via 2546AnyEvent can be forced to load any event model via
2399L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2584L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2400 2585
2401Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2586Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2402L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2587L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2403L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2588L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2404L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>. 2589L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2405 2590
2406Non-blocking file handles, sockets, TCP clients and 2591Non-blocking file handles, sockets, TCP clients and
2407servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 2592servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2408 2593
2409Asynchronous DNS: L<AnyEvent::DNS>. 2594Asynchronous DNS: L<AnyEvent::DNS>.

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