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Revision 1.275 by root, Sun Aug 9 00:24:35 2009 UTC vs.
Revision 1.316 by root, Mon Mar 15 18:51:30 2010 UTC

363might affect timers and time-outs. 363might affect timers and time-outs.
364 364
365When 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
366event loop's idea of "current time". 366event loop's idea of "current time".
367 367
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
368Note 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.
369 376
370=back 377=back
371 378
372=head2 SIGNAL WATCHERS 379=head2 SIGNAL WATCHERS
395correctly. 402correctly.
396 403
397Example: exit on SIGINT 404Example: exit on SIGINT
398 405
399 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 406 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
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).
400 424
401=head3 Signal Races, Delays and Workarounds 425=head3 Signal Races, Delays and Workarounds
402 426
403Many 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
404callbacks to signals in a generic way, which is a pity, as you cannot 428callbacks to signals in a generic way, which is a pity, as you cannot
479 503
480=head2 IDLE WATCHERS 504=head2 IDLE WATCHERS
481 505
482 $w = AnyEvent->idle (cb => <callback>); 506 $w = AnyEvent->idle (cb => <callback>);
483 507
484Sometimes there is a need to do something, but it is not so important 508Repeatedly invoke the callback after the process becomes idle, until
485to do it instantly, but only when there is nothing better to do. This 509either the watcher is destroyed or new events have been detected.
486"nothing better to do" is usually defined to be "no other events need
487attention by the event loop".
488 510
489Idle watchers ideally get invoked when the event loop has nothing 511Idle watchers are useful when there is a need to do something, but it
490better to do, just before it would block the process to wait for new 512is not so important (or wise) to do it instantly. The callback will be
491events. Instead of blocking, the idle watcher is invoked. 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.
492 519
493Most event loops unfortunately do not really support idle watchers (only 520Unfortunately, most event loops do not really support idle watchers (only
494EV, 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
495will simply call the callback "from time to time". 522will simply call the callback "from time to time".
496 523
497Example: read lines from STDIN, but only process them when the 524Example: read lines from STDIN, but only process them when the
498program is otherwise idle: 525program is otherwise idle:
592 after => 1, 619 after => 1,
593 cb => sub { $result_ready->send }, 620 cb => sub { $result_ready->send },
594 ); 621 );
595 622
596 # this "blocks" (while handling events) till the callback 623 # this "blocks" (while handling events) till the callback
597 # calls -<send 624 # calls ->send
598 $result_ready->recv; 625 $result_ready->recv;
599 626
600Example: 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
601variables are also callable directly. 628variables are also callable directly.
602 629
666one. 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
667to use a condition variable for the whole process. 694to use a condition variable for the whole process.
668 695
669Every 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
670C<< ->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
671>>, 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
672is 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
673callback 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.
674 702
675You 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
676sends), 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
677condition (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).
678 706
705begung can potentially be zero: 733begung can potentially be zero:
706 734
707 my $cv = AnyEvent->condvar; 735 my $cv = AnyEvent->condvar;
708 736
709 my %result; 737 my %result;
710 $cv->begin (sub { $cv->send (\%result) }); 738 $cv->begin (sub { shift->send (\%result) });
711 739
712 for my $host (@list_of_hosts) { 740 for my $host (@list_of_hosts) {
713 $cv->begin; 741 $cv->begin;
714 ping_host_then_call_callback $host, sub { 742 ping_host_then_call_callback $host, sub {
715 $result{$host} = ...; 743 $result{$host} = ...;
806=over 4 834=over 4
807 835
808=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.
809 837
810EV 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
811use. 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
812that, will fall back to its own pure-perl implementation, which is 840pure-perl implementation, which is available everywhere as it comes with
813available everywhere as it comes with AnyEvent itself. 841AnyEvent itself.
814 842
815 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 843 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
816 AnyEvent::Impl::Event based on Event, very stable, few glitches.
817 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 844 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
818 845
819=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.
820 847
821These 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
822is 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
823them. This means that AnyEvent will automatically pick the right backend 850them. This means that AnyEvent will automatically pick the right backend
824when the main program loads an event module before anything starts to 851when the main program loads an event module before anything starts to
825create watchers. Nothing special needs to be done by the main program. 852create watchers. Nothing special needs to be done by the main program.
826 853
854 AnyEvent::Impl::Event based on Event, very stable, few glitches.
827 AnyEvent::Impl::Glib based on Glib, slow but very stable. 855 AnyEvent::Impl::Glib based on Glib, slow but very stable.
828 AnyEvent::Impl::Tk based on Tk, very broken. 856 AnyEvent::Impl::Tk based on Tk, very broken.
829 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 857 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
830 AnyEvent::Impl::POE based on POE, very slow, some limitations. 858 AnyEvent::Impl::POE based on POE, very slow, some limitations.
831 AnyEvent::Impl::Irssi used when running within irssi. 859 AnyEvent::Impl::Irssi used when running within irssi.
941You should check C<$AnyEvent::MODEL> before adding to this array, though: 969You should check C<$AnyEvent::MODEL> before adding to this array, though:
942if 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
943array will be ignored. 971array will be ignored.
944 972
945Best use C<AnyEvent::post_detect { BLOCK }> when your application allows 973Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
946it,as it takes care of these details. 974it, as it takes care of these details.
947 975
948This variable is mainly useful for modules that can do something useful 976This variable is mainly useful for modules that can do something useful
949when 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
950not 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
951into 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 }
952 993
953=back 994=back
954 995
955=head1 WHAT TO DO IN A MODULE 996=head1 WHAT TO DO IN A MODULE
956 997
1105 1146
1106package AnyEvent; 1147package AnyEvent;
1107 1148
1108# basically a tuned-down version of common::sense 1149# basically a tuned-down version of common::sense
1109sub common_sense { 1150sub common_sense {
1110 # no warnings 1151 # from common:.sense 1.0
1111 ${^WARNING_BITS} ^= ${^WARNING_BITS}; 1152 ${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
1112 # use strict vars subs 1153 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1113 $^H |= 0x00000600; 1154 $^H |= 0x00000600;
1114} 1155}
1115 1156
1116BEGIN { AnyEvent::common_sense } 1157BEGIN { AnyEvent::common_sense }
1117 1158
1118use Carp (); 1159use Carp ();
1119 1160
1120our $VERSION = 4.92; 1161our $VERSION = '5.251';
1121our $MODEL; 1162our $MODEL;
1122 1163
1123our $AUTOLOAD; 1164our $AUTOLOAD;
1124our @ISA; 1165our @ISA;
1125 1166
1126our @REGISTRY; 1167our @REGISTRY;
1127 1168
1128our $WIN32;
1129
1130our $VERBOSE; 1169our $VERBOSE;
1131 1170
1132BEGIN { 1171BEGIN {
1133 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1172 require "AnyEvent/constants.pl";
1173
1134 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1174 eval "sub TAINT (){" . (${^TAINT} *1) . "}";
1135 1175
1136 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1176 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1137 if ${^TAINT}; 1177 if ${^TAINT};
1138 1178
1139 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1179 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1151 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1191 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1152} 1192}
1153 1193
1154my @models = ( 1194my @models = (
1155 [EV:: => AnyEvent::Impl::EV:: , 1], 1195 [EV:: => AnyEvent::Impl::EV:: , 1],
1156 [Event:: => AnyEvent::Impl::Event::, 1],
1157 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], 1196 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1158 # everything below here will not (normally) be autoprobed 1197 # everything below here will not (normally) be autoprobed
1159 # as the pureperl backend should work everywhere 1198 # as the pureperl backend should work everywhere
1160 # and is usually faster 1199 # and is usually faster
1200 [Event:: => AnyEvent::Impl::Event::, 1],
1161 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers 1201 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1162 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1202 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1163 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package 1203 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1164 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1204 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1165 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1205 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1168 [Prima:: => AnyEvent::Impl::POE::], 1208 [Prima:: => AnyEvent::Impl::POE::],
1169 # IO::Async is just too broken - we would need workarounds for its 1209 # IO::Async is just too broken - we would need workarounds for its
1170 # byzantine signal and broken child handling, among others. 1210 # byzantine signal and broken child handling, among others.
1171 # IO::Async is rather hard to detect, as it doesn't have any 1211 # IO::Async is rather hard to detect, as it doesn't have any
1172 # obvious default class. 1212 # obvious default class.
1173# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1213 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1174# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1214 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1175# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program 1215 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1216 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1176); 1217);
1177 1218
1178our %method = map +($_ => 1), 1219our %method = map +($_ => 1),
1179 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1220 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1180 1221
1199sub AnyEvent::Util::postdetect::DESTROY { 1240sub AnyEvent::Util::postdetect::DESTROY {
1200 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1241 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1201} 1242}
1202 1243
1203sub detect() { 1244sub detect() {
1245 # free some memory
1246 *detect = sub () { $MODEL };
1247
1248 local $!; # for good measure
1249 local $SIG{__DIE__};
1250
1251 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1252 my $model = "AnyEvent::Impl::$1";
1253 if (eval "require $model") {
1254 $MODEL = $model;
1255 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1256 } else {
1257 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1258 }
1259 }
1260
1261 # check for already loaded models
1204 unless ($MODEL) { 1262 unless ($MODEL) {
1205 local $SIG{__DIE__}; 1263 for (@REGISTRY, @models) {
1206 1264 my ($package, $model) = @$_;
1207 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1265 if (${"$package\::VERSION"} > 0) {
1208 my $model = "AnyEvent::Impl::$1";
1209 if (eval "require $model") { 1266 if (eval "require $model") {
1210 $MODEL = $model; 1267 $MODEL = $model;
1211 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; 1268 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1212 } else { 1269 last;
1213 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; 1270 }
1214 } 1271 }
1215 } 1272 }
1216 1273
1217 # check for already loaded models
1218 unless ($MODEL) { 1274 unless ($MODEL) {
1275 # try to autoload a model
1219 for (@REGISTRY, @models) { 1276 for (@REGISTRY, @models) {
1220 my ($package, $model) = @$_; 1277 my ($package, $model, $autoload) = @$_;
1278 if (
1279 $autoload
1280 and eval "require $package"
1221 if (${"$package\::VERSION"} > 0) { 1281 and ${"$package\::VERSION"} > 0
1222 if (eval "require $model") { 1282 and eval "require $model"
1283 ) {
1223 $MODEL = $model; 1284 $MODEL = $model;
1224 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2; 1285 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1225 last; 1286 last;
1226 }
1227 } 1287 }
1228 } 1288 }
1229 1289
1230 unless ($MODEL) {
1231 # try to autoload a model
1232 for (@REGISTRY, @models) {
1233 my ($package, $model, $autoload) = @$_;
1234 if (
1235 $autoload
1236 and eval "require $package"
1237 and ${"$package\::VERSION"} > 0
1238 and eval "require $model"
1239 ) {
1240 $MODEL = $model;
1241 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1242 last;
1243 }
1244 }
1245
1246 $MODEL 1290 $MODEL
1247 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; 1291 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1248 }
1249 } 1292 }
1250
1251 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1252
1253 unshift @ISA, $MODEL;
1254
1255 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1256
1257 (shift @post_detect)->() while @post_detect;
1258 } 1293 }
1294
1295 @models = (); # free probe data
1296
1297 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1298 unshift @ISA, $MODEL;
1299
1300 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1301
1302 (shift @post_detect)->() while @post_detect;
1259 1303
1260 $MODEL 1304 $MODEL
1261} 1305}
1262 1306
1263sub AUTOLOAD { 1307sub AUTOLOAD {
1264 (my $func = $AUTOLOAD) =~ s/.*://; 1308 (my $func = $AUTOLOAD) =~ s/.*://;
1265 1309
1266 $method{$func} 1310 $method{$func}
1267 or Carp::croak "$func: not a valid method for AnyEvent objects"; 1311 or Carp::croak "$func: not a valid AnyEvent class method";
1268 1312
1269 detect unless $MODEL; 1313 detect;
1270 1314
1271 my $class = shift; 1315 my $class = shift;
1272 $class->$func (@_); 1316 $class->$func (@_);
1273} 1317}
1274 1318
1287 # we assume CLOEXEC is already set by perl in all important cases 1331 # we assume CLOEXEC is already set by perl in all important cases
1288 1332
1289 ($fh2, $rw) 1333 ($fh2, $rw)
1290} 1334}
1291 1335
1292############################################################################# 1336=head1 SIMPLIFIED AE API
1293# "new" API, currently only emulation of it 1337
1294############################################################################# 1338Starting with version 5.0, AnyEvent officially supports a second, much
1339simpler, API that is designed to reduce the calling, typing and memory
1340overhead.
1341
1342See the L<AE> manpage for details.
1343
1344=cut
1295 1345
1296package AE; 1346package AE;
1297 1347
1298our $VERSION = $AnyEvent::VERSION; 1348our $VERSION = $AnyEvent::VERSION;
1299 1349
1300sub io($$$) { 1350sub io($$$) {
1301 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) 1351 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1302} 1352}
1303 1353
1304sub timer($$$) { 1354sub timer($$$) {
1305 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]); 1355 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1306} 1356}
1307 1357
1308sub signal($$) { 1358sub signal($$) {
1309 AnyEvent->signal (signal => $_[0], cb => $_[1]); 1359 AnyEvent->signal (signal => $_[0], cb => $_[1])
1310} 1360}
1311 1361
1312sub child($$) { 1362sub child($$) {
1313 AnyEvent->child (pid => $_[0], cb => $_[1]); 1363 AnyEvent->child (pid => $_[0], cb => $_[1])
1314} 1364}
1315 1365
1316sub idle($) { 1366sub idle($) {
1317 AnyEvent->idle (cb => $_[0]); 1367 AnyEvent->idle (cb => $_[0])
1318} 1368}
1319 1369
1320sub cv(;&) { 1370sub cv(;&) {
1321 AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) 1371 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1322} 1372}
1335 1385
1336package AnyEvent::Base; 1386package AnyEvent::Base;
1337 1387
1338# default implementations for many methods 1388# default implementations for many methods
1339 1389
1340sub _time { 1390sub _time() {
1391 eval q{ # poor man's autoloading
1341 # probe for availability of Time::HiRes 1392 # probe for availability of Time::HiRes
1342 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1393 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1343 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1394 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1344 *_time = \&Time::HiRes::time; 1395 *_time = \&Time::HiRes::time;
1345 # if (eval "use POSIX (); (POSIX::times())... 1396 # if (eval "use POSIX (); (POSIX::times())...
1346 } else { 1397 } else {
1347 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; 1398 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1348 *_time = sub { time }; # epic fail 1399 *_time = sub (){ time }; # epic fail
1400 }
1349 } 1401 };
1402 die if $@;
1350 1403
1351 &_time 1404 &_time
1352} 1405}
1353 1406
1354sub time { _time } 1407sub time { _time }
1365 1418
1366our $HAVE_ASYNC_INTERRUPT; 1419our $HAVE_ASYNC_INTERRUPT;
1367 1420
1368sub _have_async_interrupt() { 1421sub _have_async_interrupt() {
1369 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} 1422 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1370 && eval "use Async::Interrupt 1.0 (); 1") 1423 && eval "use Async::Interrupt 1.02 (); 1")
1371 unless defined $HAVE_ASYNC_INTERRUPT; 1424 unless defined $HAVE_ASYNC_INTERRUPT;
1372 1425
1373 $HAVE_ASYNC_INTERRUPT 1426 $HAVE_ASYNC_INTERRUPT
1374} 1427}
1375 1428
1376our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1429our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1377our (%SIG_ASY, %SIG_ASY_W); 1430our (%SIG_ASY, %SIG_ASY_W);
1378our ($SIG_COUNT, $SIG_TW); 1431our ($SIG_COUNT, $SIG_TW);
1379 1432
1380sub _signal_exec {
1381 $HAVE_ASYNC_INTERRUPT
1382 ? $SIGPIPE_R->drain
1383 : sysread $SIGPIPE_R, my $dummy, 9;
1384
1385 while (%SIG_EV) {
1386 for (keys %SIG_EV) {
1387 delete $SIG_EV{$_};
1388 $_->() for values %{ $SIG_CB{$_} || {} };
1389 }
1390 }
1391}
1392
1393# install a dummy wakeup watcher to reduce signal catching latency 1433# install a dummy wakeup watcher to reduce signal catching latency
1434# used by Impls
1394sub _sig_add() { 1435sub _sig_add() {
1395 unless ($SIG_COUNT++) { 1436 unless ($SIG_COUNT++) {
1396 # try to align timer on a full-second boundary, if possible 1437 # try to align timer on a full-second boundary, if possible
1397 my $NOW = AE::now; 1438 my $NOW = AE::now;
1398 1439
1450 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec; 1491 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1451 1492
1452 } else { 1493 } else {
1453 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8; 1494 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1454 1495
1455 require Fcntl;
1456
1457 if (AnyEvent::WIN32) { 1496 if (AnyEvent::WIN32) {
1458 require AnyEvent::Util; 1497 require AnyEvent::Util;
1459 1498
1460 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); 1499 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1461 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R; 1500 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1462 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case 1501 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1463 } else { 1502 } else {
1464 pipe $SIGPIPE_R, $SIGPIPE_W; 1503 pipe $SIGPIPE_R, $SIGPIPE_W;
1465 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1504 fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1466 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case 1505 fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1467 1506
1468 # not strictly required, as $^F is normally 2, but let's make sure... 1507 # not strictly required, as $^F is normally 2, but let's make sure...
1469 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1508 fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1470 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1509 fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1471 } 1510 }
1472 1511
1473 $SIGPIPE_R 1512 $SIGPIPE_R
1474 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1513 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1475 1514
1529 # print weird messages, or just unconditionally exit 1568 # print weird messages, or just unconditionally exit
1530 # instead of getting the default action. 1569 # instead of getting the default action.
1531 undef $SIG{$signal} 1570 undef $SIG{$signal}
1532 unless keys %{ $SIG_CB{$signal} }; 1571 unless keys %{ $SIG_CB{$signal} };
1533 }; 1572 };
1573
1574 *_signal_exec = sub {
1575 $HAVE_ASYNC_INTERRUPT
1576 ? $SIGPIPE_R->drain
1577 : sysread $SIGPIPE_R, (my $dummy), 9;
1578
1579 while (%SIG_EV) {
1580 for (keys %SIG_EV) {
1581 delete $SIG_EV{$_};
1582 $_->() for values %{ $SIG_CB{$_} || {} };
1583 }
1584 }
1585 };
1534 }; 1586 };
1535 die if $@; 1587 die if $@;
1588
1536 &signal 1589 &signal
1537} 1590}
1538 1591
1539# default implementation for ->child 1592# default implementation for ->child
1540 1593
1541our %PID_CB; 1594our %PID_CB;
1542our $CHLD_W; 1595our $CHLD_W;
1543our $CHLD_DELAY_W; 1596our $CHLD_DELAY_W;
1544our $WNOHANG; 1597our $WNOHANG;
1545 1598
1599# used by many Impl's
1546sub _emit_childstatus($$) { 1600sub _emit_childstatus($$) {
1547 my (undef, $rpid, $rstatus) = @_; 1601 my (undef, $rpid, $rstatus) = @_;
1548 1602
1549 $_->($rpid, $rstatus) 1603 $_->($rpid, $rstatus)
1550 for values %{ $PID_CB{$rpid} || {} }, 1604 for values %{ $PID_CB{$rpid} || {} },
1551 values %{ $PID_CB{0} || {} }; 1605 values %{ $PID_CB{0} || {} };
1552} 1606}
1553 1607
1554sub _sigchld {
1555 my $pid;
1556
1557 AnyEvent->_emit_childstatus ($pid, $?)
1558 while ($pid = waitpid -1, $WNOHANG) > 0;
1559}
1560
1561sub child { 1608sub child {
1609 eval q{ # poor man's autoloading {}
1610 *_sigchld = sub {
1611 my $pid;
1612
1613 AnyEvent->_emit_childstatus ($pid, $?)
1614 while ($pid = waitpid -1, $WNOHANG) > 0;
1615 };
1616
1617 *child = sub {
1562 my (undef, %arg) = @_; 1618 my (undef, %arg) = @_;
1563 1619
1564 defined (my $pid = $arg{pid} + 0) 1620 defined (my $pid = $arg{pid} + 0)
1565 or Carp::croak "required option 'pid' is missing"; 1621 or Carp::croak "required option 'pid' is missing";
1566 1622
1567 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1623 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1568 1624
1569 # WNOHANG is almost cetrainly 1 everywhere 1625 # WNOHANG is almost cetrainly 1 everywhere
1570 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/ 1626 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1571 ? 1 1627 ? 1
1572 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1628 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1573 1629
1574 unless ($CHLD_W) { 1630 unless ($CHLD_W) {
1575 $CHLD_W = AE::signal CHLD => \&_sigchld; 1631 $CHLD_W = AE::signal CHLD => \&_sigchld;
1576 # child could be a zombie already, so make at least one round 1632 # child could be a zombie already, so make at least one round
1577 &_sigchld; 1633 &_sigchld;
1578 } 1634 }
1579 1635
1580 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1636 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1581} 1637 };
1582 1638
1583sub AnyEvent::Base::child::DESTROY { 1639 *AnyEvent::Base::child::DESTROY = sub {
1584 my ($pid, $cb) = @{$_[0]}; 1640 my ($pid, $cb) = @{$_[0]};
1585 1641
1586 delete $PID_CB{$pid}{$cb}; 1642 delete $PID_CB{$pid}{$cb};
1587 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1643 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1588 1644
1589 undef $CHLD_W unless keys %PID_CB; 1645 undef $CHLD_W unless keys %PID_CB;
1646 };
1647 };
1648 die if $@;
1649
1650 &child
1590} 1651}
1591 1652
1592# idle emulation is done by simply using a timer, regardless 1653# idle emulation is done by simply using a timer, regardless
1593# of whether the process is idle or not, and not letting 1654# of whether the process is idle or not, and not letting
1594# the callback use more than 50% of the time. 1655# the callback use more than 50% of the time.
1595sub idle { 1656sub idle {
1657 eval q{ # poor man's autoloading {}
1658 *idle = sub {
1596 my (undef, %arg) = @_; 1659 my (undef, %arg) = @_;
1597 1660
1598 my ($cb, $w, $rcb) = $arg{cb}; 1661 my ($cb, $w, $rcb) = $arg{cb};
1599 1662
1600 $rcb = sub { 1663 $rcb = sub {
1601 if ($cb) { 1664 if ($cb) {
1602 $w = _time; 1665 $w = _time;
1603 &$cb; 1666 &$cb;
1604 $w = _time - $w; 1667 $w = _time - $w;
1605 1668
1606 # never use more then 50% of the time for the idle watcher, 1669 # never use more then 50% of the time for the idle watcher,
1607 # within some limits 1670 # within some limits
1608 $w = 0.0001 if $w < 0.0001; 1671 $w = 0.0001 if $w < 0.0001;
1609 $w = 5 if $w > 5; 1672 $w = 5 if $w > 5;
1610 1673
1611 $w = AE::timer $w, 0, $rcb; 1674 $w = AE::timer $w, 0, $rcb;
1612 } else { 1675 } else {
1613 # clean up... 1676 # clean up...
1614 undef $w; 1677 undef $w;
1615 undef $rcb; 1678 undef $rcb;
1679 }
1680 };
1681
1682 $w = AE::timer 0.05, 0, $rcb;
1683
1684 bless \\$cb, "AnyEvent::Base::idle"
1616 } 1685 };
1686
1687 *AnyEvent::Base::idle::DESTROY = sub {
1688 undef $${$_[0]};
1689 };
1617 }; 1690 };
1691 die if $@;
1618 1692
1619 $w = AE::timer 0.05, 0, $rcb; 1693 &idle
1620
1621 bless \\$cb, "AnyEvent::Base::idle"
1622}
1623
1624sub AnyEvent::Base::idle::DESTROY {
1625 undef $${$_[0]};
1626} 1694}
1627 1695
1628package AnyEvent::CondVar; 1696package AnyEvent::CondVar;
1629 1697
1630our @ISA = AnyEvent::CondVar::Base::; 1698our @ISA = AnyEvent::CondVar::Base::;
1904 warn "read: $input\n"; # output what has been read 1972 warn "read: $input\n"; # output what has been read
1905 $cv->send if $input =~ /^q/i; # quit program if /^q/i 1973 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1906 }, 1974 },
1907 ); 1975 );
1908 1976
1909 my $time_watcher; # can only be used once
1910
1911 sub new_timer {
1912 $timer = AnyEvent->timer (after => 1, cb => sub { 1977 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1913 warn "timeout\n"; # print 'timeout' about every second 1978 warn "timeout\n"; # print 'timeout' at most every second
1914 &new_timer; # and restart the time
1915 }); 1979 });
1916 }
1917
1918 new_timer; # create first timer
1919 1980
1920 $cv->recv; # wait until user enters /^q/i 1981 $cv->recv; # wait until user enters /^q/i
1921 1982
1922=head1 REAL-WORLD EXAMPLE 1983=head1 REAL-WORLD EXAMPLE
1923 1984
2054through AnyEvent. The benchmark creates a lot of timers (with a zero 2115through AnyEvent. The benchmark creates a lot of timers (with a zero
2055timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2116timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
2056which it is), lets them fire exactly once and destroys them again. 2117which it is), lets them fire exactly once and destroys them again.
2057 2118
2058Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2119Source code for this benchmark is found as F<eg/bench> in the AnyEvent
2059distribution. 2120distribution. It uses the L<AE> interface, which makes a real difference
2121for the EV and Perl backends only.
2060 2122
2061=head3 Explanation of the columns 2123=head3 Explanation of the columns
2062 2124
2063I<watcher> is the number of event watchers created/destroyed. Since 2125I<watcher> is the number of event watchers created/destroyed. Since
2064different event models feature vastly different performances, each event 2126different event models feature vastly different performances, each event
2085watcher. 2147watcher.
2086 2148
2087=head3 Results 2149=head3 Results
2088 2150
2089 name watchers bytes create invoke destroy comment 2151 name watchers bytes create invoke destroy comment
2090 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2152 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
2091 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2153 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
2092 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2154 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
2093 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2155 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
2094 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2156 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
2095 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2157 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2096 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll 2158 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2097 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll 2159 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
2098 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2160 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
2099 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2161 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
2100 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2162 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
2101 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2163 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
2102 2164
2103=head3 Discussion 2165=head3 Discussion
2104 2166
2105The benchmark does I<not> measure scalability of the event loop very 2167The benchmark does I<not> measure scalability of the event loop very
2106well. For example, a select-based event loop (such as the pure perl one) 2168well. For example, a select-based event loop (such as the pure perl one)
2118benchmark machine, handling an event takes roughly 1600 CPU cycles with 2180benchmark machine, handling an event takes roughly 1600 CPU cycles with
2119EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2181EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2120cycles with POE. 2182cycles with POE.
2121 2183
2122C<EV> is the sole leader regarding speed and memory use, which are both 2184C<EV> is the sole leader regarding speed and memory use, which are both
2123maximal/minimal, respectively. Even when going through AnyEvent, it uses 2185maximal/minimal, respectively. When using the L<AE> API there is zero
2186overhead (when going through the AnyEvent API create is about 5-6 times
2187slower, with other times being equal, so still uses far less memory than
2124far less memory than any other event loop and is still faster than Event 2188any other event loop and is still faster than Event natively).
2125natively.
2126 2189
2127The pure perl implementation is hit in a few sweet spots (both the 2190The pure perl implementation is hit in a few sweet spots (both the
2128constant timeout and the use of a single fd hit optimisations in the perl 2191constant timeout and the use of a single fd hit optimisations in the perl
2129interpreter and the backend itself). Nevertheless this shows that it 2192interpreter and the backend itself). Nevertheless this shows that it
2130adds very little overhead in itself. Like any select-based backend its 2193adds very little overhead in itself. Like any select-based backend its
2204In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2267In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2205(1%) are active. This mirrors the activity of large servers with many 2268(1%) are active. This mirrors the activity of large servers with many
2206connections, most of which are idle at any one point in time. 2269connections, most of which are idle at any one point in time.
2207 2270
2208Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2271Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2209distribution. 2272distribution. It uses the L<AE> interface, which makes a real difference
2273for the EV and Perl backends only.
2210 2274
2211=head3 Explanation of the columns 2275=head3 Explanation of the columns
2212 2276
2213I<sockets> is the number of sockets, and twice the number of "servers" (as 2277I<sockets> is the number of sockets, and twice the number of "servers" (as
2214each server has a read and write socket end). 2278each server has a read and write socket end).
2222a new one that moves the timeout into the future. 2286a new one that moves the timeout into the future.
2223 2287
2224=head3 Results 2288=head3 Results
2225 2289
2226 name sockets create request 2290 name sockets create request
2227 EV 20000 69.01 11.16 2291 EV 20000 62.66 7.99
2228 Perl 20000 73.32 35.87 2292 Perl 20000 68.32 32.64
2229 IOAsync 20000 157.00 98.14 epoll 2293 IOAsync 20000 174.06 101.15 epoll
2230 IOAsync 20000 159.31 616.06 poll 2294 IOAsync 20000 174.67 610.84 poll
2231 Event 20000 212.62 257.32 2295 Event 20000 202.69 242.91
2232 Glib 20000 651.16 1896.30 2296 Glib 20000 557.01 1689.52
2233 POE 20000 349.67 12317.24 uses POE::Loop::Event 2297 POE 20000 341.54 12086.32 uses POE::Loop::Event
2234 2298
2235=head3 Discussion 2299=head3 Discussion
2236 2300
2237This benchmark I<does> measure scalability and overall performance of the 2301This benchmark I<does> measure scalability and overall performance of the
2238particular event loop. 2302particular event loop.
2364As you can see, the AnyEvent + EV combination even beats the 2428As you can see, the AnyEvent + EV combination even beats the
2365hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl 2429hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2366backend easily beats IO::Lambda and POE. 2430backend easily beats IO::Lambda and POE.
2367 2431
2368And even the 100% non-blocking version written using the high-level (and 2432And even the 100% non-blocking version written using the high-level (and
2369slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a 2433slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2370large margin, even though it does all of DNS, tcp-connect and socket I/O 2434higher level ("unoptimised") abstractions by a large margin, even though
2371in a non-blocking way. 2435it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2372 2436
2373The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and 2437The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2374F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are 2438F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2375part of the IO::lambda distribution and were used without any changes. 2439part of the IO::Lambda distribution and were used without any changes.
2376 2440
2377 2441
2378=head1 SIGNALS 2442=head1 SIGNALS
2379 2443
2380AnyEvent currently installs handlers for these signals: 2444AnyEvent currently installs handlers for these signals:
2422it's built-in modules) are required to use it. 2486it's built-in modules) are required to use it.
2423 2487
2424That does not mean that AnyEvent won't take advantage of some additional 2488That does not mean that AnyEvent won't take advantage of some additional
2425modules if they are installed. 2489modules if they are installed.
2426 2490
2427This section epxlains which additional modules will be used, and how they 2491This section explains which additional modules will be used, and how they
2428affect AnyEvent's operetion. 2492affect AnyEvent's operation.
2429 2493
2430=over 4 2494=over 4
2431 2495
2432=item L<Async::Interrupt> 2496=item L<Async::Interrupt>
2433 2497
2438catch the signals) with some delay (default is 10 seconds, look for 2502catch the signals) with some delay (default is 10 seconds, look for
2439C<$AnyEvent::MAX_SIGNAL_LATENCY>). 2503C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2440 2504
2441If this module is available, then it will be used to implement signal 2505If this module is available, then it will be used to implement signal
2442catching, which means that signals will not be delayed, and the event loop 2506catching, which means that signals will not be delayed, and the event loop
2443will not be interrupted regularly, which is more efficient (And good for 2507will not be interrupted regularly, which is more efficient (and good for
2444battery life on laptops). 2508battery life on laptops).
2445 2509
2446This affects not just the pure-perl event loop, but also other event loops 2510This affects not just the pure-perl event loop, but also other event loops
2447that have no signal handling on their own (e.g. Glib, Tk, Qt). 2511that have no signal handling on their own (e.g. Glib, Tk, Qt).
2448 2512
2460automatic timer adjustments even when no monotonic clock is available, 2524automatic timer adjustments even when no monotonic clock is available,
2461can take avdantage of advanced kernel interfaces such as C<epoll> and 2525can take avdantage of advanced kernel interfaces such as C<epoll> and
2462C<kqueue>, and is the fastest backend I<by far>. You can even embed 2526C<kqueue>, and is the fastest backend I<by far>. You can even embed
2463L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>). 2527L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2464 2528
2529If you only use backends that rely on another event loop (e.g. C<Tk>),
2530then this module will do nothing for you.
2531
2465=item L<Guard> 2532=item L<Guard>
2466 2533
2467The guard module, when used, will be used to implement 2534The guard module, when used, will be used to implement
2468C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a 2535C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2469lot less memory), but otherwise doesn't affect guard operation much. It is 2536lot less memory), but otherwise doesn't affect guard operation much. It is
2470purely used for performance. 2537purely used for performance.
2471 2538
2472=item L<JSON> and L<JSON::XS> 2539=item L<JSON> and L<JSON::XS>
2473 2540
2474This module is required when you want to read or write JSON data via 2541One of these modules is required when you want to read or write JSON data
2475L<AnyEvent::Handle>. It is also written in pure-perl, but can take 2542via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2476advantage of the ultra-high-speed L<JSON::XS> module when it is installed. 2543advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2477
2478In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2479installed.
2480 2544
2481=item L<Net::SSLeay> 2545=item L<Net::SSLeay>
2482 2546
2483Implementing TLS/SSL in Perl is certainly interesting, but not very 2547Implementing TLS/SSL in Perl is certainly interesting, but not very
2484worthwhile: If this module is installed, then L<AnyEvent::Handle> (with 2548worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2495 2559
2496 2560
2497=head1 FORK 2561=head1 FORK
2498 2562
2499Most event libraries are not fork-safe. The ones who are usually are 2563Most event libraries are not fork-safe. The ones who are usually are
2500because they rely on inefficient but fork-safe C<select> or C<poll> 2564because they rely on inefficient but fork-safe C<select> or C<poll> calls
2501calls. Only L<EV> is fully fork-aware. 2565- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2566are usually badly thought-out hacks that are incompatible with fork in
2567one way or another. Only L<EV> is fully fork-aware and ensures that you
2568continue event-processing in both parent and child (or both, if you know
2569what you are doing).
2570
2571This means that, in general, you cannot fork and do event processing in
2572the child if the event library was initialised before the fork (which
2573usually happens when the first AnyEvent watcher is created, or the library
2574is loaded).
2502 2575
2503If you have to fork, you must either do so I<before> creating your first 2576If you have to fork, you must either do so I<before> creating your first
2504watcher OR you must not use AnyEvent at all in the child OR you must do 2577watcher OR you must not use AnyEvent at all in the child OR you must do
2505something completely out of the scope of AnyEvent. 2578something completely out of the scope of AnyEvent.
2579
2580The problem of doing event processing in the parent I<and> the child
2581is much more complicated: even for backends that I<are> fork-aware or
2582fork-safe, their behaviour is not usually what you want: fork clones all
2583watchers, that means all timers, I/O watchers etc. are active in both
2584parent and child, which is almost never what you want. USing C<exec>
2585to start worker children from some kind of manage rprocess is usually
2586preferred, because it is much easier and cleaner, at the expense of having
2587to have another binary.
2506 2588
2507 2589
2508=head1 SECURITY CONSIDERATIONS 2590=head1 SECURITY CONSIDERATIONS
2509 2591
2510AnyEvent can be forced to load any event model via 2592AnyEvent can be forced to load any event model via

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