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Revision 1.258 by root, Sun Jul 26 05:57:05 2009 UTC vs.
Revision 1.309 by root, Sat Dec 26 08:59:35 2009 UTC

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
446
447 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
402 448
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 (one some backends, 451The child process is specified by the C<pid> argument (one some backends,
406using C<0> watches for any child process exit, on others this will 452using C<0> watches for any child process exit, on others this will
455 # do something else, then wait for process exit 501 # do something else, then wait for process exit
456 $done->recv; 502 $done->recv;
457 503
458=head2 IDLE WATCHERS 504=head2 IDLE WATCHERS
459 505
460Sometimes there is a need to do something, but it is not so important 506 $w = AnyEvent->idle (cb => <callback>);
461to do it instantly, but only when there is nothing better to do. This
462"nothing better to do" is usually defined to be "no other events need
463attention by the event loop".
464 507
465Idle watchers ideally get invoked when the event loop has nothing 508Repeatedly invoke the callback after the process becomes idle, until
466better to do, just before it would block the process to wait for new 509either the watcher is destroyed or new events have been detected.
467events. Instead of blocking, the idle watcher is invoked.
468 510
469Most event loops unfortunately do not really support idle watchers (only 511Idle watchers are useful when there is a need to do something, but it
512is not so important (or wise) to do it instantly. The callback will be
513invoked only when there is "nothing better to do", which is usually
514defined as "all outstanding events have been handled and no new events
515have been detected". That means that idle watchers ideally get invoked
516when the event loop has just polled for new events but none have been
517detected. Instead of blocking to wait for more events, the idle watchers
518will be invoked.
519
520Unfortunately, most event loops do not really support idle watchers (only
470EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent 521EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
471will simply call the callback "from time to time". 522will simply call the callback "from time to time".
472 523
473Example: read lines from STDIN, but only process them when the 524Example: read lines from STDIN, but only process them when the
474program is otherwise idle: 525program is otherwise idle:
490 }); 541 });
491 }); 542 });
492 543
493=head2 CONDITION VARIABLES 544=head2 CONDITION VARIABLES
494 545
546 $cv = AnyEvent->condvar;
547
548 $cv->send (<list>);
549 my @res = $cv->recv;
550
495If you are familiar with some event loops you will know that all of them 551If you are familiar with some event loops you will know that all of them
496require you to run some blocking "loop", "run" or similar function that 552require you to run some blocking "loop", "run" or similar function that
497will actively watch for new events and call your callbacks. 553will actively watch for new events and call your callbacks.
498 554
499AnyEvent is slightly different: it expects somebody else to run the event 555AnyEvent is slightly different: it expects somebody else to run the event
563 after => 1, 619 after => 1,
564 cb => sub { $result_ready->send }, 620 cb => sub { $result_ready->send },
565 ); 621 );
566 622
567 # this "blocks" (while handling events) till the callback 623 # this "blocks" (while handling events) till the callback
568 # calls -<send 624 # calls ->send
569 $result_ready->recv; 625 $result_ready->recv;
570 626
571Example: wait for a timer, but take advantage of the fact that condition 627Example: wait for a timer, but take advantage of the fact that condition
572variables are also callable directly. 628variables are also callable directly.
573 629
637one. For example, a function that pings many hosts in parallel might want 693one. For example, a function that pings many hosts in parallel might want
638to use a condition variable for the whole process. 694to use a condition variable for the whole process.
639 695
640Every call to C<< ->begin >> will increment a counter, and every call to 696Every call to C<< ->begin >> will increment a counter, and every call to
641C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 697C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
642>>, the (last) callback passed to C<begin> will be executed. That callback 698>>, the (last) callback passed to C<begin> will be executed, passing the
643is I<supposed> to call C<< ->send >>, but that is not required. If no 699condvar as first argument. That callback is I<supposed> to call C<< ->send
644callback was set, C<send> will be called without any arguments. 700>>, but that is not required. If no group callback was set, C<send> will
701be called without any arguments.
645 702
646You can think of C<< $cv->send >> giving you an OR condition (one call 703You can think of C<< $cv->send >> giving you an OR condition (one call
647sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND 704sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
648condition (all C<begin> calls must be C<end>'ed before the condvar sends). 705condition (all C<begin> calls must be C<end>'ed before the condvar sends).
649 706
676begung can potentially be zero: 733begung can potentially be zero:
677 734
678 my $cv = AnyEvent->condvar; 735 my $cv = AnyEvent->condvar;
679 736
680 my %result; 737 my %result;
681 $cv->begin (sub { $cv->send (\%result) }); 738 $cv->begin (sub { shift->send (\%result) });
682 739
683 for my $host (@list_of_hosts) { 740 for my $host (@list_of_hosts) {
684 $cv->begin; 741 $cv->begin;
685 ping_host_then_call_callback $host, sub { 742 ping_host_then_call_callback $host, sub {
686 $result{$host} = ...; 743 $result{$host} = ...;
761=item $cb = $cv->cb ($cb->($cv)) 818=item $cb = $cv->cb ($cb->($cv))
762 819
763This is a mutator function that returns the callback set and optionally 820This is a mutator function that returns the callback set and optionally
764replaces it before doing so. 821replaces it before doing so.
765 822
766The callback will be called when the condition becomes "true", i.e. when 823The callback will be called when the condition becomes (or already was)
767C<send> or C<croak> are called, with the only argument being the condition 824"true", i.e. when C<send> or C<croak> are called (or were called), with
768variable itself. Calling C<recv> inside the callback or at any later time 825the only argument being the condition variable itself. Calling C<recv>
769is guaranteed not to block. 826inside the callback or at any later time is guaranteed not to block.
770 827
771=back 828=back
772 829
773=head1 SUPPORTED EVENT LOOPS/BACKENDS 830=head1 SUPPORTED EVENT LOOPS/BACKENDS
774 831
777=over 4 834=over 4
778 835
779=item Backends that are autoprobed when no other event loop can be found. 836=item Backends that are autoprobed when no other event loop can be found.
780 837
781EV is the preferred backend when no other event loop seems to be in 838EV is the preferred backend when no other event loop seems to be in
782use. If EV is not installed, then AnyEvent will try Event, and, failing 839use. If EV is not installed, then AnyEvent will fall back to its own
783that, will fall back to its own pure-perl implementation, which is 840pure-perl implementation, which is available everywhere as it comes with
784available everywhere as it comes with AnyEvent itself. 841AnyEvent itself.
785 842
786 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 843 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
787 AnyEvent::Impl::Event based on Event, very stable, few glitches.
788 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 844 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
789 845
790=item Backends that are transparently being picked up when they are used. 846=item Backends that are transparently being picked up when they are used.
791 847
792These will be used when they are currently loaded when the first watcher 848These will be used when they are currently loaded when the first watcher
793is created, in which case it is assumed that the application is using 849is created, in which case it is assumed that the application is using
794them. This means that AnyEvent will automatically pick the right backend 850them. This means that AnyEvent will automatically pick the right backend
795when the main program loads an event module before anything starts to 851when the main program loads an event module before anything starts to
796create watchers. Nothing special needs to be done by the main program. 852create watchers. Nothing special needs to be done by the main program.
797 853
854 AnyEvent::Impl::Event based on Event, very stable, few glitches.
798 AnyEvent::Impl::Glib based on Glib, slow but very stable. 855 AnyEvent::Impl::Glib based on Glib, slow but very stable.
799 AnyEvent::Impl::Tk based on Tk, very broken. 856 AnyEvent::Impl::Tk based on Tk, very broken.
800 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 857 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
801 AnyEvent::Impl::POE based on POE, very slow, some limitations. 858 AnyEvent::Impl::POE based on POE, very slow, some limitations.
802 AnyEvent::Impl::Irssi used when running within irssi. 859 AnyEvent::Impl::Irssi used when running within irssi.
912You should check C<$AnyEvent::MODEL> before adding to this array, though: 969You should check C<$AnyEvent::MODEL> before adding to this array, though:
913if it is defined then the event loop has already been detected, and the 970if it is defined then the event loop has already been detected, and the
914array will be ignored. 971array will be ignored.
915 972
916Best use C<AnyEvent::post_detect { BLOCK }> when your application allows 973Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
917it,as it takes care of these details. 974it, as it takes care of these details.
918 975
919This variable is mainly useful for modules that can do something useful 976This variable is mainly useful for modules that can do something useful
920when AnyEvent is used and thus want to know when it is initialised, but do 977when AnyEvent is used and thus want to know when it is initialised, but do
921not need to even load it by default. This array provides the means to hook 978not need to even load it by default. This array provides the means to hook
922into AnyEvent passively, without loading it. 979into AnyEvent passively, without loading it.
980
981Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
982together, you could put this into Coro (this is the actual code used by
983Coro to accomplish this):
984
985 if (defined $AnyEvent::MODEL) {
986 # AnyEvent already initialised, so load Coro::AnyEvent
987 require Coro::AnyEvent;
988 } else {
989 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
990 # as soon as it is
991 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
992 }
923 993
924=back 994=back
925 995
926=head1 WHAT TO DO IN A MODULE 996=head1 WHAT TO DO IN A MODULE
927 997
1076 1146
1077package AnyEvent; 1147package AnyEvent;
1078 1148
1079# basically a tuned-down version of common::sense 1149# basically a tuned-down version of common::sense
1080sub common_sense { 1150sub common_sense {
1081 # no warnings 1151 # from common:.sense 1.0
1082 ${^WARNING_BITS} ^= ${^WARNING_BITS}; 1152 ${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
1083 # use strict vars subs 1153 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1084 $^H |= 0x00000600; 1154 $^H |= 0x00000600;
1085} 1155}
1086 1156
1087BEGIN { AnyEvent::common_sense } 1157BEGIN { AnyEvent::common_sense }
1088 1158
1089use Carp (); 1159use Carp ();
1090 1160
1091our $VERSION = 4.87; 1161our $VERSION = '5.23';
1092our $MODEL; 1162our $MODEL;
1093 1163
1094our $AUTOLOAD; 1164our $AUTOLOAD;
1095our @ISA; 1165our @ISA;
1096 1166
1097our @REGISTRY; 1167our @REGISTRY;
1098
1099our $WIN32;
1100 1168
1101our $VERBOSE; 1169our $VERBOSE;
1102 1170
1103BEGIN { 1171BEGIN {
1104 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1172 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
1122 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1190 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1123} 1191}
1124 1192
1125my @models = ( 1193my @models = (
1126 [EV:: => AnyEvent::Impl::EV:: , 1], 1194 [EV:: => AnyEvent::Impl::EV:: , 1],
1127 [Event:: => AnyEvent::Impl::Event::, 1],
1128 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], 1195 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1129 # everything below here will not (normally) be autoprobed 1196 # everything below here will not (normally) be autoprobed
1130 # as the pureperl backend should work everywhere 1197 # as the pureperl backend should work everywhere
1131 # and is usually faster 1198 # and is usually faster
1199 [Event:: => AnyEvent::Impl::Event::, 1],
1132 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers 1200 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1133 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1201 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1134 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package 1202 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1135 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1203 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1136 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1204 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1139 [Prima:: => AnyEvent::Impl::POE::], 1207 [Prima:: => AnyEvent::Impl::POE::],
1140 # IO::Async is just too broken - we would need workarounds for its 1208 # IO::Async is just too broken - we would need workarounds for its
1141 # byzantine signal and broken child handling, among others. 1209 # byzantine signal and broken child handling, among others.
1142 # IO::Async is rather hard to detect, as it doesn't have any 1210 # IO::Async is rather hard to detect, as it doesn't have any
1143 # obvious default class. 1211 # obvious default class.
1144# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1212 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1145# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1213 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1146# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program 1214 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1215 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1147); 1216);
1148 1217
1149our %method = map +($_ => 1), 1218our %method = map +($_ => 1),
1150 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1219 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1151 1220
1258 # we assume CLOEXEC is already set by perl in all important cases 1327 # we assume CLOEXEC is already set by perl in all important cases
1259 1328
1260 ($fh2, $rw) 1329 ($fh2, $rw)
1261} 1330}
1262 1331
1332=head1 SIMPLIFIED AE API
1333
1334Starting with version 5.0, AnyEvent officially supports a second, much
1335simpler, API that is designed to reduce the calling, typing and memory
1336overhead.
1337
1338See the L<AE> manpage for details.
1339
1340=cut
1341
1342package AE;
1343
1344our $VERSION = $AnyEvent::VERSION;
1345
1346sub io($$$) {
1347 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1348}
1349
1350sub timer($$$) {
1351 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1352}
1353
1354sub signal($$) {
1355 AnyEvent->signal (signal => $_[0], cb => $_[1])
1356}
1357
1358sub child($$) {
1359 AnyEvent->child (pid => $_[0], cb => $_[1])
1360}
1361
1362sub idle($) {
1363 AnyEvent->idle (cb => $_[0])
1364}
1365
1366sub cv(;&) {
1367 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1368}
1369
1370sub now() {
1371 AnyEvent->now
1372}
1373
1374sub now_update() {
1375 AnyEvent->now_update
1376}
1377
1378sub time() {
1379 AnyEvent->time
1380}
1381
1263package AnyEvent::Base; 1382package AnyEvent::Base;
1264 1383
1265# default implementations for many methods 1384# default implementations for many methods
1266 1385
1267sub _time { 1386sub _time() {
1268 # probe for availability of Time::HiRes 1387 # probe for availability of Time::HiRes
1269 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1388 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1270 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1389 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1271 *_time = \&Time::HiRes::time; 1390 *_time = \&Time::HiRes::time;
1272 # if (eval "use POSIX (); (POSIX::times())... 1391 # if (eval "use POSIX (); (POSIX::times())...
1289} 1408}
1290 1409
1291# default implementation for ->signal 1410# default implementation for ->signal
1292 1411
1293our $HAVE_ASYNC_INTERRUPT; 1412our $HAVE_ASYNC_INTERRUPT;
1413
1414sub _have_async_interrupt() {
1415 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1416 && eval "use Async::Interrupt 1.02 (); 1")
1417 unless defined $HAVE_ASYNC_INTERRUPT;
1418
1419 $HAVE_ASYNC_INTERRUPT
1420}
1421
1294our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1422our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1295our (%SIG_ASY, %SIG_ASY_W); 1423our (%SIG_ASY, %SIG_ASY_W);
1296our ($SIG_COUNT, $SIG_TW); 1424our ($SIG_COUNT, $SIG_TW);
1297 1425
1298sub _signal_exec { 1426sub _signal_exec {
1299 $HAVE_ASYNC_INTERRUPT 1427 $HAVE_ASYNC_INTERRUPT
1300 ? $SIGPIPE_R->drain 1428 ? $SIGPIPE_R->drain
1301 : sysread $SIGPIPE_R, my $dummy, 9; 1429 : sysread $SIGPIPE_R, (my $dummy), 9;
1302 1430
1303 while (%SIG_EV) { 1431 while (%SIG_EV) {
1304 for (keys %SIG_EV) { 1432 for (keys %SIG_EV) {
1305 delete $SIG_EV{$_}; 1433 delete $SIG_EV{$_};
1306 $_->() for values %{ $SIG_CB{$_} || {} }; 1434 $_->() for values %{ $SIG_CB{$_} || {} };
1307 } 1435 }
1308 } 1436 }
1309} 1437}
1310 1438
1311# install a dumym wakeupw atcher to reduce signal catching latency 1439# install a dummy wakeup watcher to reduce signal catching latency
1312sub _sig_add() { 1440sub _sig_add() {
1313 unless ($SIG_COUNT++) { 1441 unless ($SIG_COUNT++) {
1314 # try to align timer on a full-second boundary, if possible 1442 # try to align timer on a full-second boundary, if possible
1315 my $NOW = AnyEvent->now; 1443 my $NOW = AE::now;
1316 1444
1317 $SIG_TW = AnyEvent->timer ( 1445 $SIG_TW = AE::timer
1318 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW), 1446 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1319 interval => $MAX_SIGNAL_LATENCY, 1447 $MAX_SIGNAL_LATENCY,
1320 cb => sub { }, # just for the PERL_ASYNC_CHECK 1448 sub { } # just for the PERL_ASYNC_CHECK
1321 ); 1449 ;
1322 } 1450 }
1323} 1451}
1324 1452
1325sub _sig_del { 1453sub _sig_del {
1326 undef $SIG_TW 1454 undef $SIG_TW
1327 unless --$SIG_COUNT; 1455 unless --$SIG_COUNT;
1328} 1456}
1329 1457
1458our $_sig_name_init; $_sig_name_init = sub {
1459 eval q{ # poor man's autoloading
1460 undef $_sig_name_init;
1461
1462 if (_have_async_interrupt) {
1463 *sig2num = \&Async::Interrupt::sig2num;
1464 *sig2name = \&Async::Interrupt::sig2name;
1465 } else {
1466 require Config;
1467
1468 my %signame2num;
1469 @signame2num{ split ' ', $Config::Config{sig_name} }
1470 = split ' ', $Config::Config{sig_num};
1471
1472 my @signum2name;
1473 @signum2name[values %signame2num] = keys %signame2num;
1474
1475 *sig2num = sub($) {
1476 $_[0] > 0 ? shift : $signame2num{+shift}
1477 };
1478 *sig2name = sub ($) {
1479 $_[0] > 0 ? $signum2name[+shift] : shift
1480 };
1481 }
1482 };
1483 die if $@;
1484};
1485
1486sub sig2num ($) { &$_sig_name_init; &sig2num }
1487sub sig2name($) { &$_sig_name_init; &sig2name }
1488
1330sub _signal { 1489sub signal {
1490 eval q{ # poor man's autoloading {}
1491 # probe for availability of Async::Interrupt
1492 if (_have_async_interrupt) {
1493 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1494
1495 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1496 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1497
1498 } else {
1499 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1500
1501 require Fcntl;
1502
1503 if (AnyEvent::WIN32) {
1504 require AnyEvent::Util;
1505
1506 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1507 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1508 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1509 } else {
1510 pipe $SIGPIPE_R, $SIGPIPE_W;
1511 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1512 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1513
1514 # not strictly required, as $^F is normally 2, but let's make sure...
1515 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1516 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1517 }
1518
1519 $SIGPIPE_R
1520 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1521
1522 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1523 }
1524
1525 *signal = sub {
1331 my (undef, %arg) = @_; 1526 my (undef, %arg) = @_;
1332 1527
1333 my $signal = uc $arg{signal} 1528 my $signal = uc $arg{signal}
1334 or Carp::croak "required option 'signal' is missing"; 1529 or Carp::croak "required option 'signal' is missing";
1335 1530
1336 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1337
1338 if ($HAVE_ASYNC_INTERRUPT) { 1531 if ($HAVE_ASYNC_INTERRUPT) {
1339 # async::interrupt 1532 # async::interrupt
1340 1533
1341 $SIG_ASY{$signal} ||= do { 1534 $signal = sig2num $signal;
1342 my $asy = new Async::Interrupt 1535 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1536
1537 $SIG_ASY{$signal} ||= new Async::Interrupt
1343 cb => sub { undef $SIG_EV{$signal} }, 1538 cb => sub { undef $SIG_EV{$signal} },
1344 signal => $signal, 1539 signal => $signal,
1345 pipe => [$SIGPIPE_R->filenos], 1540 pipe => [$SIGPIPE_R->filenos],
1541 pipe_autodrain => 0,
1542 ;
1543
1544 } else {
1545 # pure perl
1546
1547 # AE::Util has been loaded in signal
1548 $signal = sig2name $signal;
1549 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1550
1551 $SIG{$signal} ||= sub {
1552 local $!;
1553 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1554 undef $SIG_EV{$signal};
1555 };
1556
1557 # can't do signal processing without introducing races in pure perl,
1558 # so limit the signal latency.
1559 _sig_add;
1346 ; 1560 }
1347 $asy->pipe_autodrain (0);
1348 1561
1349 $asy 1562 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1350 }; 1563 };
1351 1564
1352 } else { 1565 *AnyEvent::Base::signal::DESTROY = sub {
1353 # pure perl 1566 my ($signal, $cb) = @{$_[0]};
1354 1567
1355 $SIG{$signal} ||= sub { 1568 _sig_del;
1356 local $!; 1569
1357 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1570 delete $SIG_CB{$signal}{$cb};
1571
1572 $HAVE_ASYNC_INTERRUPT
1573 ? delete $SIG_ASY{$signal}
1574 : # delete doesn't work with older perls - they then
1575 # print weird messages, or just unconditionally exit
1576 # instead of getting the default action.
1358 undef $SIG_EV{$signal}; 1577 undef $SIG{$signal}
1578 unless keys %{ $SIG_CB{$signal} };
1359 }; 1579 };
1360
1361 # can't do signal processing without introducing races in pure perl,
1362 # so limit the signal latency.
1363 _sig_add;
1364 } 1580 };
1365 1581 die if $@;
1366 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1367}
1368
1369sub signal {
1370 # probe for availability of Async::Interrupt
1371 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1372 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1373
1374 $HAVE_ASYNC_INTERRUPT = 1;
1375 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1376 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1377
1378 } else {
1379 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1380
1381 require Fcntl;
1382
1383 if (AnyEvent::WIN32) {
1384 require AnyEvent::Util;
1385
1386 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1387 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1388 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1389 } else {
1390 pipe $SIGPIPE_R, $SIGPIPE_W;
1391 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1392 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1393
1394 # not strictly required, as $^F is normally 2, but let's make sure...
1395 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1396 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1397 }
1398
1399 $SIGPIPE_R
1400 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1401
1402 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1403 }
1404
1405 *signal = \&_signal;
1406 &signal 1582 &signal
1407}
1408
1409sub AnyEvent::Base::signal::DESTROY {
1410 my ($signal, $cb) = @{$_[0]};
1411
1412 _sig_del;
1413
1414 delete $SIG_CB{$signal}{$cb};
1415
1416 $HAVE_ASYNC_INTERRUPT
1417 ? delete $SIG_ASY{$signal}
1418 : # delete doesn't work with older perls - they then
1419 # print weird messages, or just unconditionally exit
1420 # instead of getting the default action.
1421 undef $SIG{$signal}
1422 unless keys %{ $SIG_CB{$signal} };
1423} 1583}
1424 1584
1425# default implementation for ->child 1585# default implementation for ->child
1426 1586
1427our %PID_CB; 1587our %PID_CB;
1456 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/ 1616 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1457 ? 1 1617 ? 1
1458 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1618 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1459 1619
1460 unless ($CHLD_W) { 1620 unless ($CHLD_W) {
1461 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1621 $CHLD_W = AE::signal CHLD => \&_sigchld;
1462 # child could be a zombie already, so make at least one round 1622 # child could be a zombie already, so make at least one round
1463 &_sigchld; 1623 &_sigchld;
1464 } 1624 }
1465 1625
1466 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1626 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1492 # never use more then 50% of the time for the idle watcher, 1652 # never use more then 50% of the time for the idle watcher,
1493 # within some limits 1653 # within some limits
1494 $w = 0.0001 if $w < 0.0001; 1654 $w = 0.0001 if $w < 0.0001;
1495 $w = 5 if $w > 5; 1655 $w = 5 if $w > 5;
1496 1656
1497 $w = AnyEvent->timer (after => $w, cb => $rcb); 1657 $w = AE::timer $w, 0, $rcb;
1498 } else { 1658 } else {
1499 # clean up... 1659 # clean up...
1500 undef $w; 1660 undef $w;
1501 undef $rcb; 1661 undef $rcb;
1502 } 1662 }
1503 }; 1663 };
1504 1664
1505 $w = AnyEvent->timer (after => 0.05, cb => $rcb); 1665 $w = AE::timer 0.05, 0, $rcb;
1506 1666
1507 bless \\$cb, "AnyEvent::Base::idle" 1667 bless \\$cb, "AnyEvent::Base::idle"
1508} 1668}
1509 1669
1510sub AnyEvent::Base::idle::DESTROY { 1670sub AnyEvent::Base::idle::DESTROY {
1564 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1724 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1565 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1725 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1566} 1726}
1567 1727
1568sub cb { 1728sub cb {
1569 $_[0]{_ae_cb} = $_[1] if @_ > 1; 1729 my $cv = shift;
1730
1731 @_
1732 and $cv->{_ae_cb} = shift
1733 and $cv->{_ae_sent}
1734 and (delete $cv->{_ae_cb})->($cv);
1735
1570 $_[0]{_ae_cb} 1736 $cv->{_ae_cb}
1571} 1737}
1572 1738
1573sub begin { 1739sub begin {
1574 ++$_[0]{_ae_counter}; 1740 ++$_[0]{_ae_counter};
1575 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1741 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1784 warn "read: $input\n"; # output what has been read 1950 warn "read: $input\n"; # output what has been read
1785 $cv->send if $input =~ /^q/i; # quit program if /^q/i 1951 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1786 }, 1952 },
1787 ); 1953 );
1788 1954
1789 my $time_watcher; # can only be used once
1790
1791 sub new_timer {
1792 $timer = AnyEvent->timer (after => 1, cb => sub { 1955 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1793 warn "timeout\n"; # print 'timeout' about every second 1956 warn "timeout\n"; # print 'timeout' at most every second
1794 &new_timer; # and restart the time
1795 }); 1957 });
1796 }
1797
1798 new_timer; # create first timer
1799 1958
1800 $cv->recv; # wait until user enters /^q/i 1959 $cv->recv; # wait until user enters /^q/i
1801 1960
1802=head1 REAL-WORLD EXAMPLE 1961=head1 REAL-WORLD EXAMPLE
1803 1962
1934through AnyEvent. The benchmark creates a lot of timers (with a zero 2093through AnyEvent. The benchmark creates a lot of timers (with a zero
1935timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2094timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1936which it is), lets them fire exactly once and destroys them again. 2095which it is), lets them fire exactly once and destroys them again.
1937 2096
1938Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2097Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1939distribution. 2098distribution. It uses the L<AE> interface, which makes a real difference
2099for the EV and Perl backends only.
1940 2100
1941=head3 Explanation of the columns 2101=head3 Explanation of the columns
1942 2102
1943I<watcher> is the number of event watchers created/destroyed. Since 2103I<watcher> is the number of event watchers created/destroyed. Since
1944different event models feature vastly different performances, each event 2104different event models feature vastly different performances, each event
1965watcher. 2125watcher.
1966 2126
1967=head3 Results 2127=head3 Results
1968 2128
1969 name watchers bytes create invoke destroy comment 2129 name watchers bytes create invoke destroy comment
1970 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2130 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1971 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2131 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1972 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2132 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1973 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2133 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1974 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2134 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1975 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2135 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1976 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll 2136 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1977 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll 2137 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1978 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2138 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1979 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2139 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1980 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2140 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1981 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2141 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1982 2142
1983=head3 Discussion 2143=head3 Discussion
1984 2144
1985The benchmark does I<not> measure scalability of the event loop very 2145The benchmark does I<not> measure scalability of the event loop very
1986well. For example, a select-based event loop (such as the pure perl one) 2146well. For example, a select-based event loop (such as the pure perl one)
1998benchmark machine, handling an event takes roughly 1600 CPU cycles with 2158benchmark machine, handling an event takes roughly 1600 CPU cycles with
1999EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2159EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2000cycles with POE. 2160cycles with POE.
2001 2161
2002C<EV> is the sole leader regarding speed and memory use, which are both 2162C<EV> is the sole leader regarding speed and memory use, which are both
2003maximal/minimal, respectively. Even when going through AnyEvent, it uses 2163maximal/minimal, respectively. When using the L<AE> API there is zero
2164overhead (when going through the AnyEvent API create is about 5-6 times
2165slower, with other times being equal, so still uses far less memory than
2004far less memory than any other event loop and is still faster than Event 2166any other event loop and is still faster than Event natively).
2005natively.
2006 2167
2007The pure perl implementation is hit in a few sweet spots (both the 2168The pure perl implementation is hit in a few sweet spots (both the
2008constant timeout and the use of a single fd hit optimisations in the perl 2169constant timeout and the use of a single fd hit optimisations in the perl
2009interpreter and the backend itself). Nevertheless this shows that it 2170interpreter and the backend itself). Nevertheless this shows that it
2010adds very little overhead in itself. Like any select-based backend its 2171adds very little overhead in itself. Like any select-based backend its
2084In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2245In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2085(1%) are active. This mirrors the activity of large servers with many 2246(1%) are active. This mirrors the activity of large servers with many
2086connections, most of which are idle at any one point in time. 2247connections, most of which are idle at any one point in time.
2087 2248
2088Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2249Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2089distribution. 2250distribution. It uses the L<AE> interface, which makes a real difference
2251for the EV and Perl backends only.
2090 2252
2091=head3 Explanation of the columns 2253=head3 Explanation of the columns
2092 2254
2093I<sockets> is the number of sockets, and twice the number of "servers" (as 2255I<sockets> is the number of sockets, and twice the number of "servers" (as
2094each server has a read and write socket end). 2256each server has a read and write socket end).
2102a new one that moves the timeout into the future. 2264a new one that moves the timeout into the future.
2103 2265
2104=head3 Results 2266=head3 Results
2105 2267
2106 name sockets create request 2268 name sockets create request
2107 EV 20000 69.01 11.16 2269 EV 20000 62.66 7.99
2108 Perl 20000 73.32 35.87 2270 Perl 20000 68.32 32.64
2109 IOAsync 20000 157.00 98.14 epoll 2271 IOAsync 20000 174.06 101.15 epoll
2110 IOAsync 20000 159.31 616.06 poll 2272 IOAsync 20000 174.67 610.84 poll
2111 Event 20000 212.62 257.32 2273 Event 20000 202.69 242.91
2112 Glib 20000 651.16 1896.30 2274 Glib 20000 557.01 1689.52
2113 POE 20000 349.67 12317.24 uses POE::Loop::Event 2275 POE 20000 341.54 12086.32 uses POE::Loop::Event
2114 2276
2115=head3 Discussion 2277=head3 Discussion
2116 2278
2117This benchmark I<does> measure scalability and overall performance of the 2279This benchmark I<does> measure scalability and overall performance of the
2118particular event loop. 2280particular event loop.
2244As you can see, the AnyEvent + EV combination even beats the 2406As you can see, the AnyEvent + EV combination even beats the
2245hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl 2407hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2246backend easily beats IO::Lambda and POE. 2408backend easily beats IO::Lambda and POE.
2247 2409
2248And even the 100% non-blocking version written using the high-level (and 2410And even the 100% non-blocking version written using the high-level (and
2249slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a 2411slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2250large margin, even though it does all of DNS, tcp-connect and socket I/O 2412higher level ("unoptimised") abstractions by a large margin, even though
2251in a non-blocking way. 2413it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2252 2414
2253The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and 2415The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2254F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are 2416F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2255part of the IO::lambda distribution and were used without any changes. 2417part of the IO::Lambda distribution and were used without any changes.
2256 2418
2257 2419
2258=head1 SIGNALS 2420=head1 SIGNALS
2259 2421
2260AnyEvent currently installs handlers for these signals: 2422AnyEvent currently installs handlers for these signals:
2302it's built-in modules) are required to use it. 2464it's built-in modules) are required to use it.
2303 2465
2304That does not mean that AnyEvent won't take advantage of some additional 2466That does not mean that AnyEvent won't take advantage of some additional
2305modules if they are installed. 2467modules if they are installed.
2306 2468
2307This section epxlains which additional modules will be used, and how they 2469This section explains which additional modules will be used, and how they
2308affect AnyEvent's operetion. 2470affect AnyEvent's operation.
2309 2471
2310=over 4 2472=over 4
2311 2473
2312=item L<Async::Interrupt> 2474=item L<Async::Interrupt>
2313 2475
2318catch the signals) with some delay (default is 10 seconds, look for 2480catch the signals) with some delay (default is 10 seconds, look for
2319C<$AnyEvent::MAX_SIGNAL_LATENCY>). 2481C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2320 2482
2321If this module is available, then it will be used to implement signal 2483If this module is available, then it will be used to implement signal
2322catching, which means that signals will not be delayed, and the event loop 2484catching, which means that signals will not be delayed, and the event loop
2323will not be interrupted regularly, which is more efficient (And good for 2485will not be interrupted regularly, which is more efficient (and good for
2324battery life on laptops). 2486battery life on laptops).
2325 2487
2326This affects not just the pure-perl event loop, but also other event loops 2488This affects not just the pure-perl event loop, but also other event loops
2327that have no signal handling on their own (e.g. Glib, Tk, Qt). 2489that have no signal handling on their own (e.g. Glib, Tk, Qt).
2328 2490
2349lot less memory), but otherwise doesn't affect guard operation much. It is 2511lot less memory), but otherwise doesn't affect guard operation much. It is
2350purely used for performance. 2512purely used for performance.
2351 2513
2352=item L<JSON> and L<JSON::XS> 2514=item L<JSON> and L<JSON::XS>
2353 2515
2354This module is required when you want to read or write JSON data via 2516One of these modules is required when you want to read or write JSON data
2355L<AnyEvent::Handle>. It is also written in pure-perl, but can take 2517via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2356advantage of the ultra-high-speed L<JSON::XS> module when it is installed. 2518advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2357 2519
2358In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is 2520In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2359installed. 2521installed.
2360 2522
2375 2537
2376 2538
2377=head1 FORK 2539=head1 FORK
2378 2540
2379Most event libraries are not fork-safe. The ones who are usually are 2541Most event libraries are not fork-safe. The ones who are usually are
2380because they rely on inefficient but fork-safe C<select> or C<poll> 2542because they rely on inefficient but fork-safe C<select> or C<poll> calls
2381calls. Only L<EV> is fully fork-aware. 2543- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2544are usually badly thought-out hacks that are incompatible with fork in
2545one way or another. Only L<EV> is fully fork-aware and ensures that you
2546continue event-processing in both parent and child (or both, if you know
2547what you are doing).
2548
2549This means that, in general, you cannot fork and do event processing in
2550the child if the event library was initialised before the fork (which
2551usually happens when the first AnyEvent watcher is created, or the library
2552is loaded).
2382 2553
2383If you have to fork, you must either do so I<before> creating your first 2554If you have to fork, you must either do so I<before> creating your first
2384watcher OR you must not use AnyEvent at all in the child OR you must do 2555watcher OR you must not use AnyEvent at all in the child OR you must do
2385something completely out of the scope of AnyEvent. 2556something completely out of the scope of AnyEvent.
2557
2558The problem of doing event processing in the parent I<and> the child
2559is much more complicated: even for backends that I<are> fork-aware or
2560fork-safe, their behaviour is not usually what you want: fork clones all
2561watchers, that means all timers, I/O watchers etc. are active in both
2562parent and child, which is almost never what you want. USing C<exec>
2563to start worker children from some kind of manage rprocess is usually
2564preferred, because it is much easier and cleaner, at the expense of having
2565to have another binary.
2386 2566
2387 2567
2388=head1 SECURITY CONSIDERATIONS 2568=head1 SECURITY CONSIDERATIONS
2389 2569
2390AnyEvent can be forced to load any event model via 2570AnyEvent can be forced to load any event model via

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