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Revision 1.149 by root, Sat May 31 01:41:22 2008 UTC vs.
Revision 1.205 by root, Sun Apr 19 12:09:46 2009 UTC

1=head1 => NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6 6
7=head1 SYNOPSIS 7=head1 SYNOPSIS
8 8
9 use AnyEvent; 9 use AnyEvent;
10 10
11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { 11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });
12 ...
13 });
14 12
15 my $w = AnyEvent->timer (after => $seconds, cb => sub { 13 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15
16 print AnyEvent->now; # prints current event loop time
17 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18
19 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20
21 my $w = AnyEvent->child (pid => $pid, cb => sub {
22 my ($pid, $status) = @_;
16 ... 23 ...
17 }); 24 });
18 25
19 my $w = AnyEvent->condvar; # stores whether a condition was flagged 26 my $w = AnyEvent->condvar; # stores whether a condition was flagged
20 $w->send; # wake up current and all future recv's 27 $w->send; # wake up current and all future recv's
21 $w->recv; # enters "main loop" till $condvar gets ->send 28 $w->recv; # enters "main loop" till $condvar gets ->send
29 # use a condvar in callback mode:
30 $w->cb (sub { $_[0]->recv });
22 31
23=head1 INTRODUCTION/TUTORIAL 32=head1 INTRODUCTION/TUTORIAL
24 33
25This manpage is mainly a reference manual. If you are interested 34This manpage is mainly a reference manual. If you are interested
26in a tutorial or some gentle introduction, have a look at the 35in a tutorial or some gentle introduction, have a look at the
33 42
34Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of 43Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
35policy> and AnyEvent is I<small and efficient>. 44policy> and AnyEvent is I<small and efficient>.
36 45
37First and foremost, I<AnyEvent is not an event model> itself, it only 46First and foremost, I<AnyEvent is not an event model> itself, it only
38interfaces to whatever event model the main program happens to use in a 47interfaces to whatever event model the main program happens to use, in a
39pragmatic way. For event models and certain classes of immortals alike, 48pragmatic way. For event models and certain classes of immortals alike,
40the statement "there can only be one" is a bitter reality: In general, 49the statement "there can only be one" is a bitter reality: In general,
41only one event loop can be active at the same time in a process. AnyEvent 50only one event loop can be active at the same time in a process. AnyEvent
42helps hiding the differences between those event loops. 51cannot change this, but it can hide the differences between those event
52loops.
43 53
44The goal of AnyEvent is to offer module authors the ability to do event 54The goal of AnyEvent is to offer module authors the ability to do event
45programming (waiting for I/O or timer events) without subscribing to a 55programming (waiting for I/O or timer events) without subscribing to a
46religion, a way of living, and most importantly: without forcing your 56religion, a way of living, and most importantly: without forcing your
47module users into the same thing by forcing them to use the same event 57module users into the same thing by forcing them to use the same event
48model you use. 58model you use.
49 59
50For modules like POE or IO::Async (which is a total misnomer as it is 60For modules like POE or IO::Async (which is a total misnomer as it is
51actually doing all I/O I<synchronously>...), using them in your module is 61actually doing all I/O I<synchronously>...), using them in your module is
52like joining a cult: After you joined, you are dependent on them and you 62like joining a cult: After you joined, you are dependent on them and you
53cannot use anything else, as it is simply incompatible to everything that 63cannot use anything else, as they are simply incompatible to everything
54isn't itself. What's worse, all the potential users of your module are 64that isn't them. What's worse, all the potential users of your
55I<also> forced to use the same event loop you use. 65module are I<also> forced to use the same event loop you use.
56 66
57AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 67AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
58fine. AnyEvent + Tk works fine etc. etc. but none of these work together 68fine. AnyEvent + Tk works fine etc. etc. but none of these work together
59with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if 69with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
60your module uses one of those, every user of your module has to use it, 70your module uses one of those, every user of your module has to use it,
61too. But if your module uses AnyEvent, it works transparently with all 71too. But if your module uses AnyEvent, it works transparently with all
62event models it supports (including stuff like POE and IO::Async, as long 72event models it supports (including stuff like IO::Async, as long as those
63as those use one of the supported event loops. It is trivial to add new 73use one of the supported event loops. It is trivial to add new event loops
64event loops to AnyEvent, too, so it is future-proof). 74to AnyEvent, too, so it is future-proof).
65 75
66In addition to being free of having to use I<the one and only true event 76In addition to being free of having to use I<the one and only true event
67model>, AnyEvent also is free of bloat and policy: with POE or similar 77model>, AnyEvent also is free of bloat and policy: with POE or similar
68modules, you get an enormous amount of code and strict rules you have to 78modules, you get an enormous amount of code and strict rules you have to
69follow. AnyEvent, on the other hand, is lean and up to the point, by only 79follow. AnyEvent, on the other hand, is lean and up to the point, by only
127These watchers are normal Perl objects with normal Perl lifetime. After 137These watchers are normal Perl objects with normal Perl lifetime. After
128creating a watcher it will immediately "watch" for events and invoke the 138creating a watcher it will immediately "watch" for events and invoke the
129callback when the event occurs (of course, only when the event model 139callback when the event occurs (of course, only when the event model
130is in control). 140is in control).
131 141
142Note that B<callbacks must not permanently change global variables>
143potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
144callbacks must not C<die> >>. The former is good programming practise in
145Perl and the latter stems from the fact that exception handling differs
146widely between event loops.
147
132To disable the watcher you have to destroy it (e.g. by setting the 148To disable the watcher you have to destroy it (e.g. by setting the
133variable you store it in to C<undef> or otherwise deleting all references 149variable you store it in to C<undef> or otherwise deleting all references
134to it). 150to it).
135 151
136All watchers are created by calling a method on the C<AnyEvent> class. 152All watchers are created by calling a method on the C<AnyEvent> class.
138Many watchers either are used with "recursion" (repeating timers for 154Many watchers either are used with "recursion" (repeating timers for
139example), or need to refer to their watcher object in other ways. 155example), or need to refer to their watcher object in other ways.
140 156
141An any way to achieve that is this pattern: 157An any way to achieve that is this pattern:
142 158
143 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 159 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
144 # you can use $w here, for example to undef it 160 # you can use $w here, for example to undef it
145 undef $w; 161 undef $w;
146 }); 162 });
147 163
148Note that C<my $w; $w => combination. This is necessary because in Perl, 164Note that C<my $w; $w => combination. This is necessary because in Perl,
149my variables are only visible after the statement in which they are 165my variables are only visible after the statement in which they are
150declared. 166declared.
151 167
152=head2 I/O WATCHERS 168=head2 I/O WATCHERS
153 169
154You can create an I/O watcher by calling the C<< AnyEvent->io >> method 170You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155with the following mandatory key-value pairs as arguments: 171with the following mandatory key-value pairs as arguments:
156 172
157C<fh> the Perl I<file handle> (I<not> file descriptor) to watch 173C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
174for events (AnyEvent might or might not keep a reference to this file
175handle). Note that only file handles pointing to things for which
176non-blocking operation makes sense are allowed. This includes sockets,
177most character devices, pipes, fifos and so on, but not for example files
178or block devices.
179
158for events. C<poll> must be a string that is either C<r> or C<w>, 180C<poll> must be a string that is either C<r> or C<w>, which creates a
159which creates a watcher waiting for "r"eadable or "w"ritable events, 181watcher waiting for "r"eadable or "w"ritable events, respectively.
182
160respectively. C<cb> is the callback to invoke each time the file handle 183C<cb> is the callback to invoke each time the file handle becomes ready.
161becomes ready.
162 184
163Although the callback might get passed parameters, their value and 185Although the callback might get passed parameters, their value and
164presence is undefined and you cannot rely on them. Portable AnyEvent 186presence is undefined and you cannot rely on them. Portable AnyEvent
165callbacks cannot use arguments passed to I/O watcher callbacks. 187callbacks cannot use arguments passed to I/O watcher callbacks.
166 188
170 192
171Some event loops issue spurious readyness notifications, so you should 193Some event loops issue spurious readyness notifications, so you should
172always use non-blocking calls when reading/writing from/to your file 194always use non-blocking calls when reading/writing from/to your file
173handles. 195handles.
174 196
175Example:
176
177 # wait for readability of STDIN, then read a line and disable the watcher 197Example: wait for readability of STDIN, then read a line and disable the
198watcher.
199
178 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { 200 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
179 chomp (my $input = <STDIN>); 201 chomp (my $input = <STDIN>);
180 warn "read: $input\n"; 202 warn "read: $input\n";
181 undef $w; 203 undef $w;
182 }); 204 });
192 214
193Although the callback might get passed parameters, their value and 215Although the callback might get passed parameters, their value and
194presence is undefined and you cannot rely on them. Portable AnyEvent 216presence is undefined and you cannot rely on them. Portable AnyEvent
195callbacks cannot use arguments passed to time watcher callbacks. 217callbacks cannot use arguments passed to time watcher callbacks.
196 218
197The timer callback will be invoked at most once: if you want a repeating 219The callback will normally be invoked once only. If you specify another
198timer you have to create a new watcher (this is a limitation by both Tk 220parameter, C<interval>, as a strictly positive number (> 0), then the
199and Glib). 221callback will be invoked regularly at that interval (in fractional
222seconds) after the first invocation. If C<interval> is specified with a
223false value, then it is treated as if it were missing.
200 224
201Example: 225The callback will be rescheduled before invoking the callback, but no
226attempt is done to avoid timer drift in most backends, so the interval is
227only approximate.
202 228
203 # fire an event after 7.7 seconds 229Example: fire an event after 7.7 seconds.
230
204 my $w = AnyEvent->timer (after => 7.7, cb => sub { 231 my $w = AnyEvent->timer (after => 7.7, cb => sub {
205 warn "timeout\n"; 232 warn "timeout\n";
206 }); 233 });
207 234
208 # to cancel the timer: 235 # to cancel the timer:
209 undef $w; 236 undef $w;
210 237
211Example 2:
212
213 # fire an event after 0.5 seconds, then roughly every second 238Example 2: fire an event after 0.5 seconds, then roughly every second.
214 my $w;
215 239
216 my $cb = sub {
217 # cancel the old timer while creating a new one
218 $w = AnyEvent->timer (after => 1, cb => $cb); 240 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
241 warn "timeout\n";
219 }; 242 };
220
221 # start the "loop" by creating the first watcher
222 $w = AnyEvent->timer (after => 0.5, cb => $cb);
223 243
224=head3 TIMING ISSUES 244=head3 TIMING ISSUES
225 245
226There are two ways to handle timers: based on real time (relative, "fire 246There are two ways to handle timers: based on real time (relative, "fire
227in 10 seconds") and based on wallclock time (absolute, "fire at 12 247in 10 seconds") and based on wallclock time (absolute, "fire at 12
300In either case, if you care (and in most cases, you don't), then you 320In either case, if you care (and in most cases, you don't), then you
301can get whatever behaviour you want with any event loop, by taking the 321can get whatever behaviour you want with any event loop, by taking the
302difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 322difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
303account. 323account.
304 324
325=item AnyEvent->now_update
326
327Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
328the current time for each loop iteration (see the discussion of L<<
329AnyEvent->now >>, above).
330
331When a callback runs for a long time (or when the process sleeps), then
332this "current" time will differ substantially from the real time, which
333might affect timers and time-outs.
334
335When this is the case, you can call this method, which will update the
336event loop's idea of "current time".
337
338Note that updating the time I<might> cause some events to be handled.
339
305=back 340=back
306 341
307=head2 SIGNAL WATCHERS 342=head2 SIGNAL WATCHERS
308 343
309You can watch for signals using a signal watcher, C<signal> is the signal 344You can watch for signals using a signal watcher, C<signal> is the signal
310I<name> without any C<SIG> prefix, C<cb> is the Perl callback to 345I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
311be invoked whenever a signal occurs. 346callback to be invoked whenever a signal occurs.
312 347
313Although the callback might get passed parameters, their value and 348Although the callback might get passed parameters, their value and
314presence is undefined and you cannot rely on them. Portable AnyEvent 349presence is undefined and you cannot rely on them. Portable AnyEvent
315callbacks cannot use arguments passed to signal watcher callbacks. 350callbacks cannot use arguments passed to signal watcher callbacks.
316 351
332=head2 CHILD PROCESS WATCHERS 367=head2 CHILD PROCESS WATCHERS
333 368
334You can also watch on a child process exit and catch its exit status. 369You can also watch on a child process exit and catch its exit status.
335 370
336The child process is specified by the C<pid> argument (if set to C<0>, it 371The child process is specified by the C<pid> argument (if set to C<0>, it
337watches for any child process exit). The watcher will trigger as often 372watches for any child process exit). The watcher will triggered only when
338as status change for the child are received. This works by installing a 373the child process has finished and an exit status is available, not on
339signal handler for C<SIGCHLD>. The callback will be called with the pid 374any trace events (stopped/continued).
340and exit status (as returned by waitpid), so unlike other watcher types, 375
341you I<can> rely on child watcher callback arguments. 376The callback will be called with the pid and exit status (as returned by
377waitpid), so unlike other watcher types, you I<can> rely on child watcher
378callback arguments.
379
380This watcher type works by installing a signal handler for C<SIGCHLD>,
381and since it cannot be shared, nothing else should use SIGCHLD or reap
382random child processes (waiting for specific child processes, e.g. inside
383C<system>, is just fine).
342 384
343There is a slight catch to child watchers, however: you usually start them 385There is a slight catch to child watchers, however: you usually start them
344I<after> the child process was created, and this means the process could 386I<after> the child process was created, and this means the process could
345have exited already (and no SIGCHLD will be sent anymore). 387have exited already (and no SIGCHLD will be sent anymore).
346 388
352AnyEvent program, you I<have> to create at least one watcher before you 394AnyEvent program, you I<have> to create at least one watcher before you
353C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 395C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
354 396
355Example: fork a process and wait for it 397Example: fork a process and wait for it
356 398
357 my $done = AnyEvent->condvar; 399 my $done = AnyEvent->condvar;
358 400
359 my $pid = fork or exit 5; 401 my $pid = fork or exit 5;
360 402
361 my $w = AnyEvent->child ( 403 my $w = AnyEvent->child (
362 pid => $pid, 404 pid => $pid,
363 cb => sub { 405 cb => sub {
364 my ($pid, $status) = @_; 406 my ($pid, $status) = @_;
365 warn "pid $pid exited with status $status"; 407 warn "pid $pid exited with status $status";
366 $done->send; 408 $done->send;
367 }, 409 },
368 ); 410 );
369 411
370 # do something else, then wait for process exit 412 # do something else, then wait for process exit
371 $done->recv; 413 $done->recv;
372 414
373=head2 CONDITION VARIABLES 415=head2 CONDITION VARIABLES
374 416
375If you are familiar with some event loops you will know that all of them 417If you are familiar with some event loops you will know that all of them
376require you to run some blocking "loop", "run" or similar function that 418require you to run some blocking "loop", "run" or similar function that
382The instrument to do that is called a "condition variable", so called 424The instrument to do that is called a "condition variable", so called
383because they represent a condition that must become true. 425because they represent a condition that must become true.
384 426
385Condition variables can be created by calling the C<< AnyEvent->condvar 427Condition variables can be created by calling the C<< AnyEvent->condvar
386>> method, usually without arguments. The only argument pair allowed is 428>> method, usually without arguments. The only argument pair allowed is
429
387C<cb>, which specifies a callback to be called when the condition variable 430C<cb>, which specifies a callback to be called when the condition variable
388becomes true. 431becomes true, with the condition variable as the first argument (but not
432the results).
389 433
390After creation, the condition variable is "false" until it becomes "true" 434After creation, the condition variable is "false" until it becomes "true"
391by calling the C<send> method (or calling the condition variable as if it 435by calling the C<send> method (or calling the condition variable as if it
392were a callback, read about the caveats in the description for the C<< 436were a callback, read about the caveats in the description for the C<<
393->send >> method). 437->send >> method).
449 493
450 my $done = AnyEvent->condvar; 494 my $done = AnyEvent->condvar;
451 my $delay = AnyEvent->timer (after => 5, cb => $done); 495 my $delay = AnyEvent->timer (after => 5, cb => $done);
452 $done->recv; 496 $done->recv;
453 497
498Example: Imagine an API that returns a condvar and doesn't support
499callbacks. This is how you make a synchronous call, for example from
500the main program:
501
502 use AnyEvent::CouchDB;
503
504 ...
505
506 my @info = $couchdb->info->recv;
507
508And this is how you would just ste a callback to be called whenever the
509results are available:
510
511 $couchdb->info->cb (sub {
512 my @info = $_[0]->recv;
513 });
514
454=head3 METHODS FOR PRODUCERS 515=head3 METHODS FOR PRODUCERS
455 516
456These methods should only be used by the producing side, i.e. the 517These methods should only be used by the producing side, i.e. the
457code/module that eventually sends the signal. Note that it is also 518code/module that eventually sends the signal. Note that it is also
458the producer side which creates the condvar in most cases, but it isn't 519the producer side which creates the condvar in most cases, but it isn't
591=item $bool = $cv->ready 652=item $bool = $cv->ready
592 653
593Returns true when the condition is "true", i.e. whether C<send> or 654Returns true when the condition is "true", i.e. whether C<send> or
594C<croak> have been called. 655C<croak> have been called.
595 656
596=item $cb = $cv->cb ([new callback]) 657=item $cb = $cv->cb ($cb->($cv))
597 658
598This is a mutator function that returns the callback set and optionally 659This is a mutator function that returns the callback set and optionally
599replaces it before doing so. 660replaces it before doing so.
600 661
601The callback will be called when the condition becomes "true", i.e. when 662The callback will be called when the condition becomes "true", i.e. when
738=item L<AnyEvent::Util> 799=item L<AnyEvent::Util>
739 800
740Contains various utility functions that replace often-used but blocking 801Contains various utility functions that replace often-used but blocking
741functions such as C<inet_aton> by event-/callback-based versions. 802functions such as C<inet_aton> by event-/callback-based versions.
742 803
743=item L<AnyEvent::Handle>
744
745Provide read and write buffers and manages watchers for reads and writes.
746
747=item L<AnyEvent::Socket> 804=item L<AnyEvent::Socket>
748 805
749Provides various utility functions for (internet protocol) sockets, 806Provides various utility functions for (internet protocol) sockets,
750addresses and name resolution. Also functions to create non-blocking tcp 807addresses and name resolution. Also functions to create non-blocking tcp
751connections or tcp servers, with IPv6 and SRV record support and more. 808connections or tcp servers, with IPv6 and SRV record support and more.
752 809
810=item L<AnyEvent::Handle>
811
812Provide read and write buffers, manages watchers for reads and writes,
813supports raw and formatted I/O, I/O queued and fully transparent and
814non-blocking SSL/TLS.
815
753=item L<AnyEvent::DNS> 816=item L<AnyEvent::DNS>
754 817
755Provides rich asynchronous DNS resolver capabilities. 818Provides rich asynchronous DNS resolver capabilities.
756 819
820=item L<AnyEvent::HTTP>
821
822A simple-to-use HTTP library that is capable of making a lot of concurrent
823HTTP requests.
824
757=item L<AnyEvent::HTTPD> 825=item L<AnyEvent::HTTPD>
758 826
759Provides a simple web application server framework. 827Provides a simple web application server framework.
760 828
761=item L<AnyEvent::FastPing> 829=item L<AnyEvent::FastPing>
762 830
763The fastest ping in the west. 831The fastest ping in the west.
764 832
833=item L<AnyEvent::DBI>
834
835Executes L<DBI> requests asynchronously in a proxy process.
836
837=item L<AnyEvent::AIO>
838
839Truly asynchronous I/O, should be in the toolbox of every event
840programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
841together.
842
843=item L<AnyEvent::BDB>
844
845Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
846L<BDB> and AnyEvent together.
847
848=item L<AnyEvent::GPSD>
849
850A non-blocking interface to gpsd, a daemon delivering GPS information.
851
852=item L<AnyEvent::IGS>
853
854A non-blocking interface to the Internet Go Server protocol (used by
855L<App::IGS>).
856
765=item L<Net::IRC3> 857=item L<AnyEvent::IRC>
766 858
767AnyEvent based IRC client module family. 859AnyEvent based IRC client module family (replacing the older Net::IRC3).
768 860
769=item L<Net::XMPP2> 861=item L<Net::XMPP2>
770 862
771AnyEvent based XMPP (Jabber protocol) module family. 863AnyEvent based XMPP (Jabber protocol) module family.
772 864
781 873
782=item L<Coro> 874=item L<Coro>
783 875
784Has special support for AnyEvent via L<Coro::AnyEvent>. 876Has special support for AnyEvent via L<Coro::AnyEvent>.
785 877
786=item L<AnyEvent::AIO>, L<IO::AIO>
787
788Truly asynchronous I/O, should be in the toolbox of every event
789programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
790together.
791
792=item L<AnyEvent::BDB>, L<BDB>
793
794Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
795IO::AIO and AnyEvent together.
796
797=item L<IO::Lambda> 878=item L<IO::Lambda>
798 879
799The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 880The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
800 881
801=back 882=back
803=cut 884=cut
804 885
805package AnyEvent; 886package AnyEvent;
806 887
807no warnings; 888no warnings;
808use strict; 889use strict qw(vars subs);
809 890
810use Carp; 891use Carp;
811 892
812our $VERSION = 4.11; 893our $VERSION = 4.351;
813our $MODEL; 894our $MODEL;
814 895
815our $AUTOLOAD; 896our $AUTOLOAD;
816our @ISA; 897our @ISA;
817 898
849 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 930 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
850 [Wx:: => AnyEvent::Impl::POE::], 931 [Wx:: => AnyEvent::Impl::POE::],
851 [Prima:: => AnyEvent::Impl::POE::], 932 [Prima:: => AnyEvent::Impl::POE::],
852); 933);
853 934
854our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 935our %method = map +($_ => 1),
936 qw(io timer time now now_update signal child condvar one_event DESTROY);
855 937
856our @post_detect; 938our @post_detect;
857 939
858sub post_detect(&) { 940sub post_detect(&) {
859 my ($cb) = @_; 941 my ($cb) = @_;
916 last; 998 last;
917 } 999 }
918 } 1000 }
919 1001
920 $MODEL 1002 $MODEL
921 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1003 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
922 } 1004 }
923 } 1005 }
924 1006
1007 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1008
925 unshift @ISA, $MODEL; 1009 unshift @ISA, $MODEL;
926 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1010
1011 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
927 1012
928 (shift @post_detect)->() while @post_detect; 1013 (shift @post_detect)->() while @post_detect;
929 } 1014 }
930 1015
931 $MODEL 1016 $MODEL
941 1026
942 my $class = shift; 1027 my $class = shift;
943 $class->$func (@_); 1028 $class->$func (@_);
944} 1029}
945 1030
1031# utility function to dup a filehandle. this is used by many backends
1032# to support binding more than one watcher per filehandle (they usually
1033# allow only one watcher per fd, so we dup it to get a different one).
1034sub _dupfh($$$$) {
1035 my ($poll, $fh, $r, $w) = @_;
1036
1037 # cygwin requires the fh mode to be matching, unix doesn't
1038 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1039 : $poll eq "w" ? ($w, ">")
1040 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1041
1042 open my $fh2, "$mode&" . fileno $fh
1043 or die "cannot dup() filehandle: $!,";
1044
1045 # we assume CLOEXEC is already set by perl in all important cases
1046
1047 ($fh2, $rw)
1048}
1049
946package AnyEvent::Base; 1050package AnyEvent::Base;
947 1051
948# default implementation for now and time 1052# default implementations for many methods
949 1053
950use Time::HiRes (); 1054BEGIN {
1055 if (eval "use Time::HiRes (); time (); 1") {
1056 *_time = \&Time::HiRes::time;
1057 # if (eval "use POSIX (); (POSIX::times())...
1058 } else {
1059 *_time = sub { time }; # epic fail
1060 }
1061}
951 1062
952sub time { Time::HiRes::time } 1063sub time { _time }
953sub now { Time::HiRes::time } 1064sub now { _time }
1065sub now_update { }
954 1066
955# default implementation for ->condvar 1067# default implementation for ->condvar
956 1068
957sub condvar { 1069sub condvar {
958 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1070 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
959} 1071}
960 1072
961# default implementation for ->signal 1073# default implementation for ->signal
962 1074
963our %SIG_CB; 1075our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1076
1077sub _signal_exec {
1078 sysread $SIGPIPE_R, my $dummy, 4;
1079
1080 while (%SIG_EV) {
1081 for (keys %SIG_EV) {
1082 delete $SIG_EV{$_};
1083 $_->() for values %{ $SIG_CB{$_} || {} };
1084 }
1085 }
1086}
964 1087
965sub signal { 1088sub signal {
966 my (undef, %arg) = @_; 1089 my (undef, %arg) = @_;
967 1090
1091 unless ($SIGPIPE_R) {
1092 require Fcntl;
1093
1094 if (AnyEvent::WIN32) {
1095 require AnyEvent::Util;
1096
1097 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1098 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1099 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1100 } else {
1101 pipe $SIGPIPE_R, $SIGPIPE_W;
1102 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1103 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1104 }
1105
1106 $SIGPIPE_R
1107 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1108
1109 # not strictly required, as $^F is normally 2, but let's make sure...
1110 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1111 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1112
1113 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1114 }
1115
968 my $signal = uc $arg{signal} 1116 my $signal = uc $arg{signal}
969 or Carp::croak "required option 'signal' is missing"; 1117 or Carp::croak "required option 'signal' is missing";
970 1118
971 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1119 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
972 $SIG{$signal} ||= sub { 1120 $SIG{$signal} ||= sub {
973 $_->() for values %{ $SIG_CB{$signal} || {} }; 1121 local $!;
1122 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1123 undef $SIG_EV{$signal};
974 }; 1124 };
975 1125
976 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1126 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
977} 1127}
978 1128
979sub AnyEvent::Base::Signal::DESTROY { 1129sub AnyEvent::Base::Signal::DESTROY {
980 my ($signal, $cb) = @{$_[0]}; 1130 my ($signal, $cb) = @{$_[0]};
981 1131
982 delete $SIG_CB{$signal}{$cb}; 1132 delete $SIG_CB{$signal}{$cb};
983 1133
984 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; 1134 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
985} 1135}
986 1136
987# default implementation for ->child 1137# default implementation for ->child
988 1138
989our %PID_CB; 1139our %PID_CB;
1097 1247
1098# undocumented/compatibility with pre-3.4 1248# undocumented/compatibility with pre-3.4
1099*broadcast = \&send; 1249*broadcast = \&send;
1100*wait = \&_wait; 1250*wait = \&_wait;
1101 1251
1252=head1 ERROR AND EXCEPTION HANDLING
1253
1254In general, AnyEvent does not do any error handling - it relies on the
1255caller to do that if required. The L<AnyEvent::Strict> module (see also
1256the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
1257checking of all AnyEvent methods, however, which is highly useful during
1258development.
1259
1260As for exception handling (i.e. runtime errors and exceptions thrown while
1261executing a callback), this is not only highly event-loop specific, but
1262also not in any way wrapped by this module, as this is the job of the main
1263program.
1264
1265The pure perl event loop simply re-throws the exception (usually
1266within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
1267$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1268so on.
1269
1270=head1 ENVIRONMENT VARIABLES
1271
1272The following environment variables are used by this module or its
1273submodules:
1274
1275=over 4
1276
1277=item C<PERL_ANYEVENT_VERBOSE>
1278
1279By default, AnyEvent will be completely silent except in fatal
1280conditions. You can set this environment variable to make AnyEvent more
1281talkative.
1282
1283When set to C<1> or higher, causes AnyEvent to warn about unexpected
1284conditions, such as not being able to load the event model specified by
1285C<PERL_ANYEVENT_MODEL>.
1286
1287When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1288model it chooses.
1289
1290=item C<PERL_ANYEVENT_STRICT>
1291
1292AnyEvent does not do much argument checking by default, as thorough
1293argument checking is very costly. Setting this variable to a true value
1294will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1295check the arguments passed to most method calls. If it finds any problems
1296it will croak.
1297
1298In other words, enables "strict" mode.
1299
1300Unlike C<use strict>, it is definitely recommended ot keep it off in
1301production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1302developing programs can be very useful, however.
1303
1304=item C<PERL_ANYEVENT_MODEL>
1305
1306This can be used to specify the event model to be used by AnyEvent, before
1307auto detection and -probing kicks in. It must be a string consisting
1308entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1309and the resulting module name is loaded and if the load was successful,
1310used as event model. If it fails to load AnyEvent will proceed with
1311auto detection and -probing.
1312
1313This functionality might change in future versions.
1314
1315For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1316could start your program like this:
1317
1318 PERL_ANYEVENT_MODEL=Perl perl ...
1319
1320=item C<PERL_ANYEVENT_PROTOCOLS>
1321
1322Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1323for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1324of auto probing).
1325
1326Must be set to a comma-separated list of protocols or address families,
1327current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1328used, and preference will be given to protocols mentioned earlier in the
1329list.
1330
1331This variable can effectively be used for denial-of-service attacks
1332against local programs (e.g. when setuid), although the impact is likely
1333small, as the program has to handle conenction and other failures anyways.
1334
1335Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1336but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1337- only support IPv4, never try to resolve or contact IPv6
1338addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1339IPv6, but prefer IPv6 over IPv4.
1340
1341=item C<PERL_ANYEVENT_EDNS0>
1342
1343Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1344for DNS. This extension is generally useful to reduce DNS traffic, but
1345some (broken) firewalls drop such DNS packets, which is why it is off by
1346default.
1347
1348Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1349EDNS0 in its DNS requests.
1350
1351=item C<PERL_ANYEVENT_MAX_FORKS>
1352
1353The maximum number of child processes that C<AnyEvent::Util::fork_call>
1354will create in parallel.
1355
1356=back
1357
1102=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1358=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1103 1359
1104This is an advanced topic that you do not normally need to use AnyEvent in 1360This is an advanced topic that you do not normally need to use AnyEvent in
1105a module. This section is only of use to event loop authors who want to 1361a module. This section is only of use to event loop authors who want to
1106provide AnyEvent compatibility. 1362provide AnyEvent compatibility.
1139 1395
1140I<rxvt-unicode> also cheats a bit by not providing blocking access to 1396I<rxvt-unicode> also cheats a bit by not providing blocking access to
1141condition variables: code blocking while waiting for a condition will 1397condition variables: code blocking while waiting for a condition will
1142C<die>. This still works with most modules/usages, and blocking calls must 1398C<die>. This still works with most modules/usages, and blocking calls must
1143not be done in an interactive application, so it makes sense. 1399not be done in an interactive application, so it makes sense.
1144
1145=head1 ENVIRONMENT VARIABLES
1146
1147The following environment variables are used by this module:
1148
1149=over 4
1150
1151=item C<PERL_ANYEVENT_VERBOSE>
1152
1153By default, AnyEvent will be completely silent except in fatal
1154conditions. You can set this environment variable to make AnyEvent more
1155talkative.
1156
1157When set to C<1> or higher, causes AnyEvent to warn about unexpected
1158conditions, such as not being able to load the event model specified by
1159C<PERL_ANYEVENT_MODEL>.
1160
1161When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1162model it chooses.
1163
1164=item C<PERL_ANYEVENT_MODEL>
1165
1166This can be used to specify the event model to be used by AnyEvent, before
1167auto detection and -probing kicks in. It must be a string consisting
1168entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1169and the resulting module name is loaded and if the load was successful,
1170used as event model. If it fails to load AnyEvent will proceed with
1171auto detection and -probing.
1172
1173This functionality might change in future versions.
1174
1175For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1176could start your program like this:
1177
1178 PERL_ANYEVENT_MODEL=Perl perl ...
1179
1180=item C<PERL_ANYEVENT_PROTOCOLS>
1181
1182Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1183for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1184of auto probing).
1185
1186Must be set to a comma-separated list of protocols or address families,
1187current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1188used, and preference will be given to protocols mentioned earlier in the
1189list.
1190
1191This variable can effectively be used for denial-of-service attacks
1192against local programs (e.g. when setuid), although the impact is likely
1193small, as the program has to handle connection errors already-
1194
1195Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1196but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1197- only support IPv4, never try to resolve or contact IPv6
1198addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1199IPv6, but prefer IPv6 over IPv4.
1200
1201=item C<PERL_ANYEVENT_EDNS0>
1202
1203Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1204for DNS. This extension is generally useful to reduce DNS traffic, but
1205some (broken) firewalls drop such DNS packets, which is why it is off by
1206default.
1207
1208Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1209EDNS0 in its DNS requests.
1210
1211=item C<PERL_ANYEVENT_MAX_FORKS>
1212
1213The maximum number of child processes that C<AnyEvent::Util::fork_call>
1214will create in parallel.
1215
1216=back
1217 1400
1218=head1 EXAMPLE PROGRAM 1401=head1 EXAMPLE PROGRAM
1219 1402
1220The following program uses an I/O watcher to read data from STDIN, a timer 1403The following program uses an I/O watcher to read data from STDIN, a timer
1221to display a message once per second, and a condition variable to quit the 1404to display a message once per second, and a condition variable to quit the
1415watcher. 1598watcher.
1416 1599
1417=head3 Results 1600=head3 Results
1418 1601
1419 name watchers bytes create invoke destroy comment 1602 name watchers bytes create invoke destroy comment
1420 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 1603 EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1421 EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers 1604 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1422 CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal 1605 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1423 Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation 1606 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1424 Event/Event 16000 516 31.88 31.30 0.85 Event native interface 1607 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1425 Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers 1608 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1426 Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour 1609 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1427 Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers 1610 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1428 POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event 1611 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1429 POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select 1612 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1430 1613
1431=head3 Discussion 1614=head3 Discussion
1432 1615
1433The benchmark does I<not> measure scalability of the event loop very 1616The benchmark does I<not> measure scalability of the event loop very
1434well. For example, a select-based event loop (such as the pure perl one) 1617well. For example, a select-based event loop (such as the pure perl one)
1636watchers, as the management overhead dominates. 1819watchers, as the management overhead dominates.
1637 1820
1638=back 1821=back
1639 1822
1640 1823
1824=head1 SIGNALS
1825
1826AnyEvent currently installs handlers for these signals:
1827
1828=over 4
1829
1830=item SIGCHLD
1831
1832A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1833emulation for event loops that do not support them natively. Also, some
1834event loops install a similar handler.
1835
1836=item SIGPIPE
1837
1838A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1839when AnyEvent gets loaded.
1840
1841The rationale for this is that AnyEvent users usually do not really depend
1842on SIGPIPE delivery (which is purely an optimisation for shell use, or
1843badly-written programs), but C<SIGPIPE> can cause spurious and rare
1844program exits as a lot of people do not expect C<SIGPIPE> when writing to
1845some random socket.
1846
1847The rationale for installing a no-op handler as opposed to ignoring it is
1848that this way, the handler will be restored to defaults on exec.
1849
1850Feel free to install your own handler, or reset it to defaults.
1851
1852=back
1853
1854=cut
1855
1856$SIG{PIPE} = sub { }
1857 unless defined $SIG{PIPE};
1858
1859
1641=head1 FORK 1860=head1 FORK
1642 1861
1643Most event libraries are not fork-safe. The ones who are usually are 1862Most event libraries are not fork-safe. The ones who are usually are
1644because they rely on inefficient but fork-safe C<select> or C<poll> 1863because they rely on inefficient but fork-safe C<select> or C<poll>
1645calls. Only L<EV> is fully fork-aware. 1864calls. Only L<EV> is fully fork-aware.
1658specified in the variable. 1877specified in the variable.
1659 1878
1660You can make AnyEvent completely ignore this variable by deleting it 1879You can make AnyEvent completely ignore this variable by deleting it
1661before the first watcher gets created, e.g. with a C<BEGIN> block: 1880before the first watcher gets created, e.g. with a C<BEGIN> block:
1662 1881
1663 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1882 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1664 1883
1665 use AnyEvent; 1884 use AnyEvent;
1666 1885
1667Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1886Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1668be used to probe what backend is used and gain other information (which is 1887be used to probe what backend is used and gain other information (which is
1669probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1888probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1889$ENV{PERL_ANYEGENT_STRICT}.
1890
1891
1892=head1 BUGS
1893
1894Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1895to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1896and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1897memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1898pronounced).
1670 1899
1671 1900
1672=head1 SEE ALSO 1901=head1 SEE ALSO
1673 1902
1674Utility functions: L<AnyEvent::Util>. 1903Utility functions: L<AnyEvent::Util>.
1691Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 1920Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1692 1921
1693 1922
1694=head1 AUTHOR 1923=head1 AUTHOR
1695 1924
1696 Marc Lehmann <schmorp@schmorp.de> 1925 Marc Lehmann <schmorp@schmorp.de>
1697 http://home.schmorp.de/ 1926 http://home.schmorp.de/
1698 1927
1699=cut 1928=cut
1700 1929
17011 19301
1702 1931

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