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Revision 1.240 by root, Fri Jul 17 14:57:03 2009 UTC vs.
Revision 1.277 by root, Sun Aug 9 13:27:23 2009 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported 5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6event loops. 6and POE are various supported event loops/environments.
7 7
8=head1 SYNOPSIS 8=head1 SYNOPSIS
9 9
10 use AnyEvent; 10 use AnyEvent;
11 11
40=head1 INTRODUCTION/TUTORIAL 40=head1 INTRODUCTION/TUTORIAL
41 41
42This manpage is mainly a reference manual. If you are interested 42This manpage is mainly a reference manual. If you are interested
43in a tutorial or some gentle introduction, have a look at the 43in a tutorial or some gentle introduction, have a look at the
44L<AnyEvent::Intro> manpage. 44L<AnyEvent::Intro> manpage.
45
46=head1 SUPPORT
47
48There is a mailinglist for discussing all things AnyEvent, and an IRC
49channel, too.
50
51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52Repository>, at L<http://anyevent.schmorp.de>, for more info.
45 53
46=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 54=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47 55
48Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 56Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49nowadays. So what is different about AnyEvent? 57nowadays. So what is different about AnyEvent?
173my variables are only visible after the statement in which they are 181my variables are only visible after the statement in which they are
174declared. 182declared.
175 183
176=head2 I/O WATCHERS 184=head2 I/O WATCHERS
177 185
186 $w = AnyEvent->io (
187 fh => <filehandle_or_fileno>,
188 poll => <"r" or "w">,
189 cb => <callback>,
190 );
191
178You 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
179with the following mandatory key-value pairs as arguments: 193with the following mandatory key-value pairs as arguments:
180 194
181C<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
182for 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
211 undef $w; 225 undef $w;
212 }); 226 });
213 227
214=head2 TIME WATCHERS 228=head2 TIME WATCHERS
215 229
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
216You can create a time watcher by calling the C<< AnyEvent->timer >> 238You can create a time watcher by calling the C<< AnyEvent->timer >>
217method with the following mandatory arguments: 239method with the following mandatory arguments:
218 240
219C<after> specifies after how many seconds (fractional values are 241C<after> specifies after how many seconds (fractional values are
220supported) 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
347 369
348=back 370=back
349 371
350=head2 SIGNAL WATCHERS 372=head2 SIGNAL WATCHERS
351 373
374 $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
375
352You can watch for signals using a signal watcher, C<signal> is the signal 376You can watch for signals using a signal watcher, C<signal> is the signal
353I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl 377I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354callback to be invoked whenever a signal occurs. 378callback to be invoked whenever a signal occurs.
355 379
356Although the callback might get passed parameters, their value and 380Although the callback might get passed parameters, their value and
361invocation, and callback invocation will be synchronous. Synchronous means 385invocation, and callback invocation will be synchronous. Synchronous means
362that it might take a while until the signal gets handled by the process, 386that it might take a while until the signal gets handled by the process,
363but it is guaranteed not to interrupt any other callbacks. 387but it is guaranteed not to interrupt any other callbacks.
364 388
365The main advantage of using these watchers is that you can share a signal 389The main advantage of using these watchers is that you can share a signal
366between multiple watchers. 390between multiple watchers, and AnyEvent will ensure that signals will not
391interrupt your program at bad times.
367 392
368This watcher might use C<%SIG>, so programs overwriting those signals 393This watcher might use C<%SIG> (depending on the event loop used),
369directly will likely not work correctly. 394so programs overwriting those signals directly will likely not work
395correctly.
370 396
371Example: exit on SIGINT 397Example: exit on SIGINT
372 398
373 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 399 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374 400
401=head3 Signal Races, Delays and Workarounds
402
403Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
404callbacks to signals in a generic way, which is a pity, as you cannot
405do race-free signal handling in perl, requiring C libraries for
406this. AnyEvent will try to do it's best, which means in some cases,
407signals will be delayed. The maximum time a signal might be delayed is
408specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
409variable can be changed only before the first signal watcher is created,
410and should be left alone otherwise. This variable determines how often
411AnyEvent polls for signals (in case a wake-up was missed). Higher values
412will cause fewer spurious wake-ups, which is better for power and CPU
413saving.
414
415All these problems can be avoided by installing the optional
416L<Async::Interrupt> module, which works with most event loops. It will not
417work with inherently broken event loops such as L<Event> or L<Event::Lib>
418(and not with L<POE> currently, as POE does it's own workaround with
419one-second latency). For those, you just have to suffer the delays.
420
375=head2 CHILD PROCESS WATCHERS 421=head2 CHILD PROCESS WATCHERS
376 422
423 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
424
377You can also watch on a child process exit and catch its exit status. 425You can also watch on a child process exit and catch its exit status.
378 426
379The child process is specified by the C<pid> argument (if set to C<0>, it 427The child process is specified by the C<pid> argument (one some backends,
380watches for any child process exit). The watcher will triggered only when 428using C<0> watches for any child process exit, on others this will
381the child process has finished and an exit status is available, not on 429croak). The watcher will be triggered only when the child process has
382any trace events (stopped/continued). 430finished and an exit status is available, not on any trace events
431(stopped/continued).
383 432
384The callback will be called with the pid and exit status (as returned by 433The callback will be called with the pid and exit status (as returned by
385waitpid), so unlike other watcher types, you I<can> rely on child watcher 434waitpid), so unlike other watcher types, you I<can> rely on child watcher
386callback arguments. 435callback arguments.
387 436
403 452
404This means you cannot create a child watcher as the very first 453This means you cannot create a child watcher as the very first
405thing in an AnyEvent program, you I<have> to create at least one 454thing in an AnyEvent program, you I<have> to create at least one
406watcher before you C<fork> the child (alternatively, you can call 455watcher before you C<fork> the child (alternatively, you can call
407C<AnyEvent::detect>). 456C<AnyEvent::detect>).
457
458As most event loops do not support waiting for child events, they will be
459emulated by AnyEvent in most cases, in which the latency and race problems
460mentioned in the description of signal watchers apply.
408 461
409Example: fork a process and wait for it 462Example: fork a process and wait for it
410 463
411 my $done = AnyEvent->condvar; 464 my $done = AnyEvent->condvar;
412 465
424 # do something else, then wait for process exit 477 # do something else, then wait for process exit
425 $done->recv; 478 $done->recv;
426 479
427=head2 IDLE WATCHERS 480=head2 IDLE WATCHERS
428 481
482 $w = AnyEvent->idle (cb => <callback>);
483
429Sometimes there is a need to do something, but it is not so important 484Sometimes there is a need to do something, but it is not so important
430to do it instantly, but only when there is nothing better to do. This 485to do it instantly, but only when there is nothing better to do. This
431"nothing better to do" is usually defined to be "no other events need 486"nothing better to do" is usually defined to be "no other events need
432attention by the event loop". 487attention by the event loop".
433 488
459 }); 514 });
460 }); 515 });
461 516
462=head2 CONDITION VARIABLES 517=head2 CONDITION VARIABLES
463 518
519 $cv = AnyEvent->condvar;
520
521 $cv->send (<list>);
522 my @res = $cv->recv;
523
464If you are familiar with some event loops you will know that all of them 524If you are familiar with some event loops you will know that all of them
465require you to run some blocking "loop", "run" or similar function that 525require you to run some blocking "loop", "run" or similar function that
466will actively watch for new events and call your callbacks. 526will actively watch for new events and call your callbacks.
467 527
468AnyEvent is slightly different: it expects somebody else to run the event 528AnyEvent is slightly different: it expects somebody else to run the event
487Condition variables are similar to callbacks, except that you can 547Condition variables are similar to callbacks, except that you can
488optionally wait for them. They can also be called merge points - points 548optionally wait for them. They can also be called merge points - points
489in time where multiple outstanding events have been processed. And yet 549in time where multiple outstanding events have been processed. And yet
490another way to call them is transactions - each condition variable can be 550another way to call them is transactions - each condition variable can be
491used to represent a transaction, which finishes at some point and delivers 551used to represent a transaction, which finishes at some point and delivers
492a result. 552a result. And yet some people know them as "futures" - a promise to
553compute/deliver something that you can wait for.
493 554
494Condition variables are very useful to signal that something has finished, 555Condition variables are very useful to signal that something has finished,
495for example, if you write a module that does asynchronous http requests, 556for example, if you write a module that does asynchronous http requests,
496then a condition variable would be the ideal candidate to signal the 557then a condition variable would be the ideal candidate to signal the
497availability of results. The user can either act when the callback is 558availability of results. The user can either act when the callback is
729=item $cb = $cv->cb ($cb->($cv)) 790=item $cb = $cv->cb ($cb->($cv))
730 791
731This is a mutator function that returns the callback set and optionally 792This is a mutator function that returns the callback set and optionally
732replaces it before doing so. 793replaces it before doing so.
733 794
734The callback will be called when the condition becomes "true", i.e. when 795The callback will be called when the condition becomes (or already was)
735C<send> or C<croak> are called, with the only argument being the condition 796"true", i.e. when C<send> or C<croak> are called (or were called), with
736variable itself. Calling C<recv> inside the callback or at any later time 797the only argument being the condition variable itself. Calling C<recv>
737is guaranteed not to block. 798inside the callback or at any later time is guaranteed not to block.
738 799
739=back 800=back
740 801
741=head1 SUPPORTED EVENT LOOPS/BACKENDS 802=head1 SUPPORTED EVENT LOOPS/BACKENDS
742 803
745=over 4 806=over 4
746 807
747=item Backends that are autoprobed when no other event loop can be found. 808=item Backends that are autoprobed when no other event loop can be found.
748 809
749EV is the preferred backend when no other event loop seems to be in 810EV is the preferred backend when no other event loop seems to be in
750use. If EV is not installed, then AnyEvent will try Event, and, failing 811use. If EV is not installed, then AnyEvent will fall back to its own
751that, will fall back to its own pure-perl implementation, which is 812pure-perl implementation, which is available everywhere as it comes with
752available everywhere as it comes with AnyEvent itself. 813AnyEvent itself.
753 814
754 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 815 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
755 AnyEvent::Impl::Event based on Event, very stable, few glitches.
756 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 816 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
757 817
758=item Backends that are transparently being picked up when they are used. 818=item Backends that are transparently being picked up when they are used.
759 819
760These will be used when they are currently loaded when the first watcher 820These will be used when they are currently loaded when the first watcher
761is created, in which case it is assumed that the application is using 821is created, in which case it is assumed that the application is using
762them. This means that AnyEvent will automatically pick the right backend 822them. This means that AnyEvent will automatically pick the right backend
763when the main program loads an event module before anything starts to 823when the main program loads an event module before anything starts to
764create watchers. Nothing special needs to be done by the main program. 824create watchers. Nothing special needs to be done by the main program.
765 825
826 AnyEvent::Impl::Event based on Event, very stable, few glitches.
766 AnyEvent::Impl::Glib based on Glib, slow but very stable. 827 AnyEvent::Impl::Glib based on Glib, slow but very stable.
767 AnyEvent::Impl::Tk based on Tk, very broken. 828 AnyEvent::Impl::Tk based on Tk, very broken.
768 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 829 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
769 AnyEvent::Impl::POE based on POE, very slow, some limitations. 830 AnyEvent::Impl::POE based on POE, very slow, some limitations.
831 AnyEvent::Impl::Irssi used when running within irssi.
770 832
771=item Backends with special needs. 833=item Backends with special needs.
772 834
773Qt requires the Qt::Application to be instantiated first, but will 835Qt requires the Qt::Application to be instantiated first, but will
774otherwise be picked up automatically. As long as the main program 836otherwise be picked up automatically. As long as the main program
848event module detection too early, for example, L<AnyEvent::AIO> creates 910event module detection too early, for example, L<AnyEvent::AIO> creates
849and installs the global L<IO::AIO> watcher in a C<post_detect> block to 911and installs the global L<IO::AIO> watcher in a C<post_detect> block to
850avoid autodetecting the event module at load time. 912avoid autodetecting the event module at load time.
851 913
852If called in scalar or list context, then it creates and returns an object 914If called in scalar or list context, then it creates and returns an object
853that automatically removes the callback again when it is destroyed. See 915that automatically removes the callback again when it is destroyed (or
916C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
854L<Coro::BDB> for a case where this is useful. 917a case where this is useful.
918
919Example: Create a watcher for the IO::AIO module and store it in
920C<$WATCHER>. Only do so after the event loop is initialised, though.
921
922 our WATCHER;
923
924 my $guard = AnyEvent::post_detect {
925 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
926 };
927
928 # the ||= is important in case post_detect immediately runs the block,
929 # as to not clobber the newly-created watcher. assigning both watcher and
930 # post_detect guard to the same variable has the advantage of users being
931 # able to just C<undef $WATCHER> if the watcher causes them grief.
932
933 $WATCHER ||= $guard;
855 934
856=item @AnyEvent::post_detect 935=item @AnyEvent::post_detect
857 936
858If there are any code references in this array (you can C<push> to it 937If there are any code references in this array (you can C<push> to it
859before or after loading AnyEvent), then they will called directly after 938before or after loading AnyEvent), then they will called directly after
1024 1103
1025=cut 1104=cut
1026 1105
1027package AnyEvent; 1106package AnyEvent;
1028 1107
1108# basically a tuned-down version of common::sense
1109sub common_sense {
1029no warnings; 1110 # no warnings
1111 ${^WARNING_BITS} ^= ${^WARNING_BITS};
1030use strict qw(vars subs); 1112 # use strict vars subs
1113 $^H |= 0x00000600;
1114}
1115
1116BEGIN { AnyEvent::common_sense }
1031 1117
1032use Carp (); 1118use Carp ();
1033 1119
1034our $VERSION = 4.83; 1120our $VERSION = 4.92;
1035our $MODEL; 1121our $MODEL;
1036 1122
1037our $AUTOLOAD; 1123our $AUTOLOAD;
1038our @ISA; 1124our @ISA;
1039 1125
1040our @REGISTRY; 1126our @REGISTRY;
1041 1127
1042our $WIN32; 1128our $WIN32;
1129
1130our $VERBOSE;
1043 1131
1044BEGIN { 1132BEGIN {
1045 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1133 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
1046 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1134 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
1047 1135
1048 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1136 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1049 if ${^TAINT}; 1137 if ${^TAINT};
1050}
1051 1138
1052our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1139 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1140
1141}
1142
1143our $MAX_SIGNAL_LATENCY = 10;
1053 1144
1054our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1145our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1055 1146
1056{ 1147{
1057 my $idx; 1148 my $idx;
1059 for reverse split /\s*,\s*/, 1150 for reverse split /\s*,\s*/,
1060 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1151 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1061} 1152}
1062 1153
1063my @models = ( 1154my @models = (
1064 [EV:: => AnyEvent::Impl::EV::], 1155 [EV:: => AnyEvent::Impl::EV:: , 1],
1065 [Event:: => AnyEvent::Impl::Event::],
1066 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1156 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1067 # everything below here will not be autoprobed 1157 # everything below here will not (normally) be autoprobed
1068 # as the pureperl backend should work everywhere 1158 # as the pureperl backend should work everywhere
1069 # and is usually faster 1159 # and is usually faster
1160 [Event:: => AnyEvent::Impl::Event::, 1],
1070 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1161 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1071 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1162 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1163 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1072 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1164 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1073 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1165 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1074 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1166 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1075 [Wx:: => AnyEvent::Impl::POE::], 1167 [Wx:: => AnyEvent::Impl::POE::],
1076 [Prima:: => AnyEvent::Impl::POE::], 1168 [Prima:: => AnyEvent::Impl::POE::],
1077 # IO::Async is just too broken - we would need workarounds for its 1169 # IO::Async is just too broken - we would need workarounds for its
1078 # byzantine signal and broken child handling, among others. 1170 # byzantine signal and broken child handling, among others.
1079 # IO::Async is rather hard to detect, as it doesn't have any 1171 # IO::Async is rather hard to detect, as it doesn't have any
1080 # obvious default class. 1172 # obvious default class.
1081# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program 1173 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1082# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program 1174 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1083# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program 1175 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1176 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1084); 1177);
1085 1178
1086our %method = map +($_ => 1), 1179our %method = map +($_ => 1),
1087 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1180 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1088 1181
1092 my ($cb) = @_; 1185 my ($cb) = @_;
1093 1186
1094 if ($MODEL) { 1187 if ($MODEL) {
1095 $cb->(); 1188 $cb->();
1096 1189
1097 1 1190 undef
1098 } else { 1191 } else {
1099 push @post_detect, $cb; 1192 push @post_detect, $cb;
1100 1193
1101 defined wantarray 1194 defined wantarray
1102 ? bless \$cb, "AnyEvent::Util::postdetect" 1195 ? bless \$cb, "AnyEvent::Util::postdetect"
1108 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1201 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1109} 1202}
1110 1203
1111sub detect() { 1204sub detect() {
1112 unless ($MODEL) { 1205 unless ($MODEL) {
1113 no strict 'refs';
1114 local $SIG{__DIE__}; 1206 local $SIG{__DIE__};
1115 1207
1116 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1208 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1117 my $model = "AnyEvent::Impl::$1"; 1209 my $model = "AnyEvent::Impl::$1";
1118 if (eval "require $model") { 1210 if (eval "require $model") {
1119 $MODEL = $model; 1211 $MODEL = $model;
1120 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1; 1212 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1121 } else { 1213 } else {
1122 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose; 1214 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1123 } 1215 }
1124 } 1216 }
1125 1217
1126 # check for already loaded models 1218 # check for already loaded models
1127 unless ($MODEL) { 1219 unless ($MODEL) {
1128 for (@REGISTRY, @models) { 1220 for (@REGISTRY, @models) {
1129 my ($package, $model) = @$_; 1221 my ($package, $model) = @$_;
1130 if (${"$package\::VERSION"} > 0) { 1222 if (${"$package\::VERSION"} > 0) {
1131 if (eval "require $model") { 1223 if (eval "require $model") {
1132 $MODEL = $model; 1224 $MODEL = $model;
1133 warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; 1225 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1134 last; 1226 last;
1135 } 1227 }
1136 } 1228 }
1137 } 1229 }
1138 1230
1139 unless ($MODEL) { 1231 unless ($MODEL) {
1140 # try to load a model 1232 # try to autoload a model
1141
1142 for (@REGISTRY, @models) { 1233 for (@REGISTRY, @models) {
1143 my ($package, $model) = @$_; 1234 my ($package, $model, $autoload) = @$_;
1235 if (
1236 $autoload
1144 if (eval "require $package" 1237 and eval "require $package"
1145 and ${"$package\::VERSION"} > 0 1238 and ${"$package\::VERSION"} > 0
1146 and eval "require $model") { 1239 and eval "require $model"
1240 ) {
1147 $MODEL = $model; 1241 $MODEL = $model;
1148 warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; 1242 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1149 last; 1243 last;
1150 } 1244 }
1151 } 1245 }
1152 1246
1153 $MODEL 1247 $MODEL
1184# allow only one watcher per fd, so we dup it to get a different one). 1278# allow only one watcher per fd, so we dup it to get a different one).
1185sub _dupfh($$;$$) { 1279sub _dupfh($$;$$) {
1186 my ($poll, $fh, $r, $w) = @_; 1280 my ($poll, $fh, $r, $w) = @_;
1187 1281
1188 # cygwin requires the fh mode to be matching, unix doesn't 1282 # cygwin requires the fh mode to be matching, unix doesn't
1189 my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">"); 1283 my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1190 1284
1191 open my $fh2, "$mode&", $fh 1285 open my $fh2, $mode, $fh
1192 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,"; 1286 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1193 1287
1194 # we assume CLOEXEC is already set by perl in all important cases 1288 # we assume CLOEXEC is already set by perl in all important cases
1195 1289
1196 ($fh2, $rw) 1290 ($fh2, $rw)
1197} 1291}
1198 1292
1293#############################################################################
1294# "new" API, currently only emulation of it
1295#############################################################################
1296
1297package AE;
1298
1299our $VERSION = $AnyEvent::VERSION;
1300
1301sub io($$$) {
1302 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1303}
1304
1305sub timer($$$) {
1306 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1307}
1308
1309sub signal($$) {
1310 AnyEvent->signal (signal => $_[0], cb => $_[1])
1311}
1312
1313sub child($$) {
1314 AnyEvent->child (pid => $_[0], cb => $_[1])
1315}
1316
1317sub idle($) {
1318 AnyEvent->idle (cb => $_[0])
1319}
1320
1321sub cv(;&) {
1322 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1323}
1324
1325sub now() {
1326 AnyEvent->now
1327}
1328
1329sub now_update() {
1330 AnyEvent->now_update
1331}
1332
1333sub time() {
1334 AnyEvent->time
1335}
1336
1199package AnyEvent::Base; 1337package AnyEvent::Base;
1200 1338
1201# default implementations for many methods 1339# default implementations for many methods
1202 1340
1203BEGIN { 1341sub _time {
1342 # probe for availability of Time::HiRes
1204 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1343 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1344 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1205 *_time = \&Time::HiRes::time; 1345 *_time = \&Time::HiRes::time;
1206 # if (eval "use POSIX (); (POSIX::times())... 1346 # if (eval "use POSIX (); (POSIX::times())...
1207 } else { 1347 } else {
1348 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1208 *_time = sub { time }; # epic fail 1349 *_time = sub { time }; # epic fail
1209 } 1350 }
1351
1352 &_time
1210} 1353}
1211 1354
1212sub time { _time } 1355sub time { _time }
1213sub now { _time } 1356sub now { _time }
1214sub now_update { } 1357sub now_update { }
1219 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1362 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1220} 1363}
1221 1364
1222# default implementation for ->signal 1365# default implementation for ->signal
1223 1366
1367our $HAVE_ASYNC_INTERRUPT;
1368
1369sub _have_async_interrupt() {
1370 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1371 && eval "use Async::Interrupt 1.0 (); 1")
1372 unless defined $HAVE_ASYNC_INTERRUPT;
1373
1374 $HAVE_ASYNC_INTERRUPT
1375}
1376
1224our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1377our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1378our (%SIG_ASY, %SIG_ASY_W);
1379our ($SIG_COUNT, $SIG_TW);
1225 1380
1226sub _signal_exec { 1381sub _signal_exec {
1382 $HAVE_ASYNC_INTERRUPT
1383 ? $SIGPIPE_R->drain
1227 sysread $SIGPIPE_R, my $dummy, 4; 1384 : sysread $SIGPIPE_R, my $dummy, 9;
1228 1385
1229 while (%SIG_EV) { 1386 while (%SIG_EV) {
1230 for (keys %SIG_EV) { 1387 for (keys %SIG_EV) {
1231 delete $SIG_EV{$_}; 1388 delete $SIG_EV{$_};
1232 $_->() for values %{ $SIG_CB{$_} || {} }; 1389 $_->() for values %{ $SIG_CB{$_} || {} };
1233 } 1390 }
1234 } 1391 }
1235} 1392}
1236 1393
1394# install a dummy wakeup watcher to reduce signal catching latency
1395sub _sig_add() {
1396 unless ($SIG_COUNT++) {
1397 # try to align timer on a full-second boundary, if possible
1398 my $NOW = AE::now;
1399
1400 $SIG_TW = AE::timer
1401 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1402 $MAX_SIGNAL_LATENCY,
1403 sub { } # just for the PERL_ASYNC_CHECK
1404 ;
1405 }
1406}
1407
1408sub _sig_del {
1409 undef $SIG_TW
1410 unless --$SIG_COUNT;
1411}
1412
1413our $_sig_name_init; $_sig_name_init = sub {
1414 eval q{ # poor man's autoloading
1415 undef $_sig_name_init;
1416
1417 if (_have_async_interrupt) {
1418 *sig2num = \&Async::Interrupt::sig2num;
1419 *sig2name = \&Async::Interrupt::sig2name;
1420 } else {
1421 require Config;
1422
1423 my %signame2num;
1424 @signame2num{ split ' ', $Config::Config{sig_name} }
1425 = split ' ', $Config::Config{sig_num};
1426
1427 my @signum2name;
1428 @signum2name[values %signame2num] = keys %signame2num;
1429
1430 *sig2num = sub($) {
1431 $_[0] > 0 ? shift : $signame2num{+shift}
1432 };
1433 *sig2name = sub ($) {
1434 $_[0] > 0 ? $signum2name[+shift] : shift
1435 };
1436 }
1437 };
1438 die if $@;
1439};
1440
1441sub sig2num ($) { &$_sig_name_init; &sig2num }
1442sub sig2name($) { &$_sig_name_init; &sig2name }
1443
1237sub signal { 1444sub signal {
1238 my (undef, %arg) = @_; 1445 eval q{ # poor man's autoloading {}
1446 # probe for availability of Async::Interrupt
1447 if (_have_async_interrupt) {
1448 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1239 1449
1240 unless ($SIGPIPE_R) { 1450 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1241 require Fcntl; 1451 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1242 1452
1243 if (AnyEvent::WIN32) {
1244 require AnyEvent::Util;
1245
1246 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1247 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1248 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1249 } else { 1453 } else {
1454 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1455
1456 require Fcntl;
1457
1458 if (AnyEvent::WIN32) {
1459 require AnyEvent::Util;
1460
1461 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1462 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1463 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1464 } else {
1250 pipe $SIGPIPE_R, $SIGPIPE_W; 1465 pipe $SIGPIPE_R, $SIGPIPE_W;
1251 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1466 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1252 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case 1467 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1253 1468
1254 # not strictly required, as $^F is normally 2, but let's make sure... 1469 # not strictly required, as $^F is normally 2, but let's make sure...
1255 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1470 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1256 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1471 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1472 }
1473
1474 $SIGPIPE_R
1475 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1476
1477 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1257 } 1478 }
1258 1479
1259 $SIGPIPE_R 1480 *signal = sub {
1260 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1481 my (undef, %arg) = @_;
1261 1482
1262 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1263 }
1264
1265 my $signal = uc $arg{signal} 1483 my $signal = uc $arg{signal}
1266 or Carp::croak "required option 'signal' is missing"; 1484 or Carp::croak "required option 'signal' is missing";
1267 1485
1486 if ($HAVE_ASYNC_INTERRUPT) {
1487 # async::interrupt
1488
1489 $signal = sig2num $signal;
1268 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1490 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1491
1492 $SIG_ASY{$signal} ||= new Async::Interrupt
1493 cb => sub { undef $SIG_EV{$signal} },
1494 signal => $signal,
1495 pipe => [$SIGPIPE_R->filenos],
1496 pipe_autodrain => 0,
1497 ;
1498
1499 } else {
1500 # pure perl
1501
1502 # AE::Util has been loaded in signal
1503 $signal = sig2name $signal;
1504 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1505
1269 $SIG{$signal} ||= sub { 1506 $SIG{$signal} ||= sub {
1270 local $!; 1507 local $!;
1271 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1508 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1272 undef $SIG_EV{$signal}; 1509 undef $SIG_EV{$signal};
1510 };
1511
1512 # can't do signal processing without introducing races in pure perl,
1513 # so limit the signal latency.
1514 _sig_add;
1515 }
1516
1517 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1518 };
1519
1520 *AnyEvent::Base::signal::DESTROY = sub {
1521 my ($signal, $cb) = @{$_[0]};
1522
1523 _sig_del;
1524
1525 delete $SIG_CB{$signal}{$cb};
1526
1527 $HAVE_ASYNC_INTERRUPT
1528 ? delete $SIG_ASY{$signal}
1529 : # delete doesn't work with older perls - they then
1530 # print weird messages, or just unconditionally exit
1531 # instead of getting the default action.
1532 undef $SIG{$signal}
1533 unless keys %{ $SIG_CB{$signal} };
1534 };
1273 }; 1535 };
1274 1536 die if $@;
1275 bless [$signal, $arg{cb}], "AnyEvent::Base::signal" 1537 &signal
1276}
1277
1278sub AnyEvent::Base::signal::DESTROY {
1279 my ($signal, $cb) = @{$_[0]};
1280
1281 delete $SIG_CB{$signal}{$cb};
1282
1283 # delete doesn't work with older perls - they then
1284 # print weird messages, or just unconditionally exit
1285 # instead of getting the default action.
1286 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1287} 1538}
1288 1539
1289# default implementation for ->child 1540# default implementation for ->child
1290 1541
1291our %PID_CB; 1542our %PID_CB;
1292our $CHLD_W; 1543our $CHLD_W;
1293our $CHLD_DELAY_W; 1544our $CHLD_DELAY_W;
1294our $WNOHANG; 1545our $WNOHANG;
1295 1546
1547sub _emit_childstatus($$) {
1548 my (undef, $rpid, $rstatus) = @_;
1549
1550 $_->($rpid, $rstatus)
1551 for values %{ $PID_CB{$rpid} || {} },
1552 values %{ $PID_CB{0} || {} };
1553}
1554
1296sub _sigchld { 1555sub _sigchld {
1556 my $pid;
1557
1558 AnyEvent->_emit_childstatus ($pid, $?)
1297 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1559 while ($pid = waitpid -1, $WNOHANG) > 0;
1298 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1299 (values %{ $PID_CB{0} || {} });
1300 }
1301} 1560}
1302 1561
1303sub child { 1562sub child {
1304 my (undef, %arg) = @_; 1563 my (undef, %arg) = @_;
1305 1564
1306 defined (my $pid = $arg{pid} + 0) 1565 defined (my $pid = $arg{pid} + 0)
1307 or Carp::croak "required option 'pid' is missing"; 1566 or Carp::croak "required option 'pid' is missing";
1308 1567
1309 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1568 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1310 1569
1570 # WNOHANG is almost cetrainly 1 everywhere
1571 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1572 ? 1
1311 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1573 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1312 1574
1313 unless ($CHLD_W) { 1575 unless ($CHLD_W) {
1314 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1576 $CHLD_W = AE::signal CHLD => \&_sigchld;
1315 # child could be a zombie already, so make at least one round 1577 # child could be a zombie already, so make at least one round
1316 &_sigchld; 1578 &_sigchld;
1317 } 1579 }
1318 1580
1319 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1581 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1345 # never use more then 50% of the time for the idle watcher, 1607 # never use more then 50% of the time for the idle watcher,
1346 # within some limits 1608 # within some limits
1347 $w = 0.0001 if $w < 0.0001; 1609 $w = 0.0001 if $w < 0.0001;
1348 $w = 5 if $w > 5; 1610 $w = 5 if $w > 5;
1349 1611
1350 $w = AnyEvent->timer (after => $w, cb => $rcb); 1612 $w = AE::timer $w, 0, $rcb;
1351 } else { 1613 } else {
1352 # clean up... 1614 # clean up...
1353 undef $w; 1615 undef $w;
1354 undef $rcb; 1616 undef $rcb;
1355 } 1617 }
1356 }; 1618 };
1357 1619
1358 $w = AnyEvent->timer (after => 0.05, cb => $rcb); 1620 $w = AE::timer 0.05, 0, $rcb;
1359 1621
1360 bless \\$cb, "AnyEvent::Base::idle" 1622 bless \\$cb, "AnyEvent::Base::idle"
1361} 1623}
1362 1624
1363sub AnyEvent::Base::idle::DESTROY { 1625sub AnyEvent::Base::idle::DESTROY {
1368 1630
1369our @ISA = AnyEvent::CondVar::Base::; 1631our @ISA = AnyEvent::CondVar::Base::;
1370 1632
1371package AnyEvent::CondVar::Base; 1633package AnyEvent::CondVar::Base;
1372 1634
1373use overload 1635#use overload
1374 '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1636# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1375 fallback => 1; 1637# fallback => 1;
1638
1639# save 300+ kilobytes by dirtily hardcoding overloading
1640${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
1641*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
1642*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
1643${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1376 1644
1377our $WAITING; 1645our $WAITING;
1378 1646
1379sub _send { 1647sub _send {
1380 # nop 1648 # nop
1411 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1679 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1412 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1680 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1413} 1681}
1414 1682
1415sub cb { 1683sub cb {
1416 $_[0]{_ae_cb} = $_[1] if @_ > 1; 1684 my $cv = shift;
1685
1686 @_
1687 and $cv->{_ae_cb} = shift
1688 and $cv->{_ae_sent}
1689 and (delete $cv->{_ae_cb})->($cv);
1690
1417 $_[0]{_ae_cb} 1691 $cv->{_ae_cb}
1418} 1692}
1419 1693
1420sub begin { 1694sub begin {
1421 ++$_[0]{_ae_counter}; 1695 ++$_[0]{_ae_counter};
1422 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 1696 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1471C<PERL_ANYEVENT_MODEL>. 1745C<PERL_ANYEVENT_MODEL>.
1472 1746
1473When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1747When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1474model it chooses. 1748model it chooses.
1475 1749
1750When set to C<8> or higher, then AnyEvent will report extra information on
1751which optional modules it loads and how it implements certain features.
1752
1476=item C<PERL_ANYEVENT_STRICT> 1753=item C<PERL_ANYEVENT_STRICT>
1477 1754
1478AnyEvent does not do much argument checking by default, as thorough 1755AnyEvent does not do much argument checking by default, as thorough
1479argument checking is very costly. Setting this variable to a true value 1756argument checking is very costly. Setting this variable to a true value
1480will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1757will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1481check the arguments passed to most method calls. If it finds any problems, 1758check the arguments passed to most method calls. If it finds any problems,
1482it will croak. 1759it will croak.
1483 1760
1484In other words, enables "strict" mode. 1761In other words, enables "strict" mode.
1485 1762
1486Unlike C<use strict>, it is definitely recommended to keep it off in 1763Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1487production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1764>>, it is definitely recommended to keep it off in production. Keeping
1488developing programs can be very useful, however. 1765C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1766can be very useful, however.
1489 1767
1490=item C<PERL_ANYEVENT_MODEL> 1768=item C<PERL_ANYEVENT_MODEL>
1491 1769
1492This can be used to specify the event model to be used by AnyEvent, before 1770This can be used to specify the event model to be used by AnyEvent, before
1493auto detection and -probing kicks in. It must be a string consisting 1771auto detection and -probing kicks in. It must be a string consisting
1555 1833
1556When neither C<ca_file> nor C<ca_path> was specified during 1834When neither C<ca_file> nor C<ca_path> was specified during
1557L<AnyEvent::TLS> context creation, and either of these environment 1835L<AnyEvent::TLS> context creation, and either of these environment
1558variables exist, they will be used to specify CA certificate locations 1836variables exist, they will be used to specify CA certificate locations
1559instead of a system-dependent default. 1837instead of a system-dependent default.
1838
1839=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1840
1841When these are set to C<1>, then the respective modules are not
1842loaded. Mostly good for testing AnyEvent itself.
1560 1843
1561=back 1844=back
1562 1845
1563=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1846=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1564 1847
2132 if $SIG{CHLD} eq 'IGNORE'; 2415 if $SIG{CHLD} eq 'IGNORE';
2133 2416
2134$SIG{PIPE} = sub { } 2417$SIG{PIPE} = sub { }
2135 unless defined $SIG{PIPE}; 2418 unless defined $SIG{PIPE};
2136 2419
2420=head1 RECOMMENDED/OPTIONAL MODULES
2421
2422One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2423it's built-in modules) are required to use it.
2424
2425That does not mean that AnyEvent won't take advantage of some additional
2426modules if they are installed.
2427
2428This section epxlains which additional modules will be used, and how they
2429affect AnyEvent's operetion.
2430
2431=over 4
2432
2433=item L<Async::Interrupt>
2434
2435This slightly arcane module is used to implement fast signal handling: To
2436my knowledge, there is no way to do completely race-free and quick
2437signal handling in pure perl. To ensure that signals still get
2438delivered, AnyEvent will start an interval timer to wake up perl (and
2439catch the signals) with some delay (default is 10 seconds, look for
2440C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2441
2442If this module is available, then it will be used to implement signal
2443catching, which means that signals will not be delayed, and the event loop
2444will not be interrupted regularly, which is more efficient (And good for
2445battery life on laptops).
2446
2447This affects not just the pure-perl event loop, but also other event loops
2448that have no signal handling on their own (e.g. Glib, Tk, Qt).
2449
2450Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2451and either employ their own workarounds (POE) or use AnyEvent's workaround
2452(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2453does nothing for those backends.
2454
2455=item L<EV>
2456
2457This module isn't really "optional", as it is simply one of the backend
2458event loops that AnyEvent can use. However, it is simply the best event
2459loop available in terms of features, speed and stability: It supports
2460the AnyEvent API optimally, implements all the watcher types in XS, does
2461automatic timer adjustments even when no monotonic clock is available,
2462can take avdantage of advanced kernel interfaces such as C<epoll> and
2463C<kqueue>, and is the fastest backend I<by far>. You can even embed
2464L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2465
2466=item L<Guard>
2467
2468The guard module, when used, will be used to implement
2469C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2470lot less memory), but otherwise doesn't affect guard operation much. It is
2471purely used for performance.
2472
2473=item L<JSON> and L<JSON::XS>
2474
2475This module is required when you want to read or write JSON data via
2476L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2477advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2478
2479In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2480installed.
2481
2482=item L<Net::SSLeay>
2483
2484Implementing TLS/SSL in Perl is certainly interesting, but not very
2485worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2486the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2487
2488=item L<Time::HiRes>
2489
2490This module is part of perl since release 5.008. It will be used when the
2491chosen event library does not come with a timing source on it's own. The
2492pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2493try to use a monotonic clock for timing stability.
2494
2495=back
2496
2497
2137=head1 FORK 2498=head1 FORK
2138 2499
2139Most event libraries are not fork-safe. The ones who are usually are 2500Most event libraries are not fork-safe. The ones who are usually are
2140because they rely on inefficient but fork-safe C<select> or C<poll> 2501because they rely on inefficient but fork-safe C<select> or C<poll>
2141calls. Only L<EV> is fully fork-aware. 2502calls. Only L<EV> is fully fork-aware.
2142 2503
2143If you have to fork, you must either do so I<before> creating your first 2504If you have to fork, you must either do so I<before> creating your first
2144watcher OR you must not use AnyEvent at all in the child. 2505watcher OR you must not use AnyEvent at all in the child OR you must do
2506something completely out of the scope of AnyEvent.
2145 2507
2146 2508
2147=head1 SECURITY CONSIDERATIONS 2509=head1 SECURITY CONSIDERATIONS
2148 2510
2149AnyEvent can be forced to load any event model via 2511AnyEvent can be forced to load any event model via
2187L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2549L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2188 2550
2189Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2551Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2190L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2552L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2191L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2553L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2192L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>. 2554L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2193 2555
2194Non-blocking file handles, sockets, TCP clients and 2556Non-blocking file handles, sockets, TCP clients and
2195servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 2557servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2196 2558
2197Asynchronous DNS: L<AnyEvent::DNS>. 2559Asynchronous DNS: L<AnyEvent::DNS>.

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