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Revision 1.209 by root, Wed May 13 13:36:49 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 # file descriptor readable
11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { 12 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
13
14 # one-shot or repeating timers
15 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
16 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
17
18 print AnyEvent->now; # prints current event loop time
19 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
20
21 # POSIX signal
22 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
23
24 # child process exit
25 my $w = AnyEvent->child (pid => $pid, cb => sub {
26 my ($pid, $status) = @_;
12 ... 27 ...
13 }); 28 });
14 29
15 my $w = AnyEvent->timer (after => $seconds, cb => sub { 30 # called when event loop idle (if applicable)
16 ... 31 my $w = AnyEvent->idle (cb => sub { ... });
17 });
18 32
19 my $w = AnyEvent->condvar; # stores whether a condition was flagged 33 my $w = AnyEvent->condvar; # stores whether a condition was flagged
20 $w->send; # wake up current and all future recv's 34 $w->send; # wake up current and all future recv's
21 $w->recv; # enters "main loop" till $condvar gets ->send 35 $w->recv; # enters "main loop" till $condvar gets ->send
36 # use a condvar in callback mode:
37 $w->cb (sub { $_[0]->recv });
38
39=head1 INTRODUCTION/TUTORIAL
40
41This manpage is mainly a reference manual. If you are interested
42in a tutorial or some gentle introduction, have a look at the
43L<AnyEvent::Intro> manpage.
22 44
23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 45=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24 46
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 47Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent? 48nowadays. So what is different about AnyEvent?
27 49
28Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of 50Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29policy> and AnyEvent is I<small and efficient>. 51policy> and AnyEvent is I<small and efficient>.
30 52
31First and foremost, I<AnyEvent is not an event model> itself, it only 53First and foremost, I<AnyEvent is not an event model> itself, it only
32interfaces to whatever event model the main program happens to use in a 54interfaces to whatever event model the main program happens to use, in a
33pragmatic way. For event models and certain classes of immortals alike, 55pragmatic way. For event models and certain classes of immortals alike,
34the statement "there can only be one" is a bitter reality: In general, 56the statement "there can only be one" is a bitter reality: In general,
35only one event loop can be active at the same time in a process. AnyEvent 57only one event loop can be active at the same time in a process. AnyEvent
36helps hiding the differences between those event loops. 58cannot change this, but it can hide the differences between those event
59loops.
37 60
38The goal of AnyEvent is to offer module authors the ability to do event 61The goal of AnyEvent is to offer module authors the ability to do event
39programming (waiting for I/O or timer events) without subscribing to a 62programming (waiting for I/O or timer events) without subscribing to a
40religion, a way of living, and most importantly: without forcing your 63religion, a way of living, and most importantly: without forcing your
41module users into the same thing by forcing them to use the same event 64module users into the same thing by forcing them to use the same event
42model you use. 65model you use.
43 66
44For modules like POE or IO::Async (which is a total misnomer as it is 67For modules like POE or IO::Async (which is a total misnomer as it is
45actually doing all I/O I<synchronously>...), using them in your module is 68actually doing all I/O I<synchronously>...), using them in your module is
46like joining a cult: After you joined, you are dependent on them and you 69like joining a cult: After you joined, you are dependent on them and you
47cannot use anything else, as it is simply incompatible to everything that 70cannot use anything else, as they are simply incompatible to everything
48isn't itself. What's worse, all the potential users of your module are 71that isn't them. What's worse, all the potential users of your
49I<also> forced to use the same event loop you use. 72module are I<also> forced to use the same event loop you use.
50 73
51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 74AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52fine. AnyEvent + Tk works fine etc. etc. but none of these work together 75fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if 76with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54your module uses one of those, every user of your module has to use it, 77your module uses one of those, every user of your module has to use it,
55too. But if your module uses AnyEvent, it works transparently with all 78too. But if your module uses AnyEvent, it works transparently with all
56event models it supports (including stuff like POE and IO::Async, as long 79event models it supports (including stuff like IO::Async, as long as those
57as those use one of the supported event loops. It is trivial to add new 80use one of the supported event loops. It is trivial to add new event loops
58event loops to AnyEvent, too, so it is future-proof). 81to AnyEvent, too, so it is future-proof).
59 82
60In addition to being free of having to use I<the one and only true event 83In addition to being free of having to use I<the one and only true event
61model>, AnyEvent also is free of bloat and policy: with POE or similar 84model>, AnyEvent also is free of bloat and policy: with POE or similar
62modules, you get an enormous amount of code and strict rules you have to 85modules, you get an enormous amount of code and strict rules you have to
63follow. AnyEvent, on the other hand, is lean and up to the point, by only 86follow. AnyEvent, on the other hand, is lean and up to the point, by only
121These watchers are normal Perl objects with normal Perl lifetime. After 144These watchers are normal Perl objects with normal Perl lifetime. After
122creating a watcher it will immediately "watch" for events and invoke the 145creating a watcher it will immediately "watch" for events and invoke the
123callback when the event occurs (of course, only when the event model 146callback when the event occurs (of course, only when the event model
124is in control). 147is in control).
125 148
149Note that B<callbacks must not permanently change global variables>
150potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
151callbacks must not C<die> >>. The former is good programming practise in
152Perl and the latter stems from the fact that exception handling differs
153widely between event loops.
154
126To disable the watcher you have to destroy it (e.g. by setting the 155To disable the watcher you have to destroy it (e.g. by setting the
127variable you store it in to C<undef> or otherwise deleting all references 156variable you store it in to C<undef> or otherwise deleting all references
128to it). 157to it).
129 158
130All watchers are created by calling a method on the C<AnyEvent> class. 159All watchers are created by calling a method on the C<AnyEvent> class.
132Many watchers either are used with "recursion" (repeating timers for 161Many watchers either are used with "recursion" (repeating timers for
133example), or need to refer to their watcher object in other ways. 162example), or need to refer to their watcher object in other ways.
134 163
135An any way to achieve that is this pattern: 164An any way to achieve that is this pattern:
136 165
137 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 166 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
138 # you can use $w here, for example to undef it 167 # you can use $w here, for example to undef it
139 undef $w; 168 undef $w;
140 }); 169 });
141 170
142Note that C<my $w; $w => combination. This is necessary because in Perl, 171Note that C<my $w; $w => combination. This is necessary because in Perl,
143my variables are only visible after the statement in which they are 172my variables are only visible after the statement in which they are
144declared. 173declared.
145 174
146=head2 I/O WATCHERS 175=head2 I/O WATCHERS
147 176
148You can create an I/O watcher by calling the C<< AnyEvent->io >> method 177You can create an I/O watcher by calling the C<< AnyEvent->io >> method
149with the following mandatory key-value pairs as arguments: 178with the following mandatory key-value pairs as arguments:
150 179
151C<fh> the Perl I<file handle> (I<not> file descriptor) to watch 180C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
181for events (AnyEvent might or might not keep a reference to this file
182handle). Note that only file handles pointing to things for which
183non-blocking operation makes sense are allowed. This includes sockets,
184most character devices, pipes, fifos and so on, but not for example files
185or block devices.
186
152for events. C<poll> must be a string that is either C<r> or C<w>, 187C<poll> must be a string that is either C<r> or C<w>, which creates a
153which creates a watcher waiting for "r"eadable or "w"ritable events, 188watcher waiting for "r"eadable or "w"ritable events, respectively.
189
154respectively. C<cb> is the callback to invoke each time the file handle 190C<cb> is the callback to invoke each time the file handle becomes ready.
155becomes ready.
156 191
157Although the callback might get passed parameters, their value and 192Although the callback might get passed parameters, their value and
158presence is undefined and you cannot rely on them. Portable AnyEvent 193presence is undefined and you cannot rely on them. Portable AnyEvent
159callbacks cannot use arguments passed to I/O watcher callbacks. 194callbacks cannot use arguments passed to I/O watcher callbacks.
160 195
164 199
165Some event loops issue spurious readyness notifications, so you should 200Some event loops issue spurious readyness notifications, so you should
166always use non-blocking calls when reading/writing from/to your file 201always use non-blocking calls when reading/writing from/to your file
167handles. 202handles.
168 203
169Example:
170
171 # wait for readability of STDIN, then read a line and disable the watcher 204Example: wait for readability of STDIN, then read a line and disable the
205watcher.
206
172 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { 207 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
173 chomp (my $input = <STDIN>); 208 chomp (my $input = <STDIN>);
174 warn "read: $input\n"; 209 warn "read: $input\n";
175 undef $w; 210 undef $w;
176 }); 211 });
186 221
187Although the callback might get passed parameters, their value and 222Although the callback might get passed parameters, their value and
188presence is undefined and you cannot rely on them. Portable AnyEvent 223presence is undefined and you cannot rely on them. Portable AnyEvent
189callbacks cannot use arguments passed to time watcher callbacks. 224callbacks cannot use arguments passed to time watcher callbacks.
190 225
191The timer callback will be invoked at most once: if you want a repeating 226The callback will normally be invoked once only. If you specify another
192timer you have to create a new watcher (this is a limitation by both Tk 227parameter, C<interval>, as a strictly positive number (> 0), then the
193and Glib). 228callback will be invoked regularly at that interval (in fractional
229seconds) after the first invocation. If C<interval> is specified with a
230false value, then it is treated as if it were missing.
194 231
195Example: 232The callback will be rescheduled before invoking the callback, but no
233attempt is done to avoid timer drift in most backends, so the interval is
234only approximate.
196 235
197 # fire an event after 7.7 seconds 236Example: fire an event after 7.7 seconds.
237
198 my $w = AnyEvent->timer (after => 7.7, cb => sub { 238 my $w = AnyEvent->timer (after => 7.7, cb => sub {
199 warn "timeout\n"; 239 warn "timeout\n";
200 }); 240 });
201 241
202 # to cancel the timer: 242 # to cancel the timer:
203 undef $w; 243 undef $w;
204 244
205Example 2:
206
207 # fire an event after 0.5 seconds, then roughly every second 245Example 2: fire an event after 0.5 seconds, then roughly every second.
208 my $w;
209 246
210 my $cb = sub {
211 # cancel the old timer while creating a new one
212 $w = AnyEvent->timer (after => 1, cb => $cb); 247 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
248 warn "timeout\n";
213 }; 249 };
214
215 # start the "loop" by creating the first watcher
216 $w = AnyEvent->timer (after => 0.5, cb => $cb);
217 250
218=head3 TIMING ISSUES 251=head3 TIMING ISSUES
219 252
220There are two ways to handle timers: based on real time (relative, "fire 253There are two ways to handle timers: based on real time (relative, "fire
221in 10 seconds") and based on wallclock time (absolute, "fire at 12 254in 10 seconds") and based on wallclock time (absolute, "fire at 12
294In either case, if you care (and in most cases, you don't), then you 327In either case, if you care (and in most cases, you don't), then you
295can get whatever behaviour you want with any event loop, by taking the 328can get whatever behaviour you want with any event loop, by taking the
296difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 329difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
297account. 330account.
298 331
332=item AnyEvent->now_update
333
334Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
335the current time for each loop iteration (see the discussion of L<<
336AnyEvent->now >>, above).
337
338When a callback runs for a long time (or when the process sleeps), then
339this "current" time will differ substantially from the real time, which
340might affect timers and time-outs.
341
342When this is the case, you can call this method, which will update the
343event loop's idea of "current time".
344
345Note that updating the time I<might> cause some events to be handled.
346
299=back 347=back
300 348
301=head2 SIGNAL WATCHERS 349=head2 SIGNAL WATCHERS
302 350
303You can watch for signals using a signal watcher, C<signal> is the signal 351You can watch for signals using a signal watcher, C<signal> is the signal
304I<name> without any C<SIG> prefix, C<cb> is the Perl callback to 352I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
305be invoked whenever a signal occurs. 353callback to be invoked whenever a signal occurs.
306 354
307Although the callback might get passed parameters, their value and 355Although the callback might get passed parameters, their value and
308presence is undefined and you cannot rely on them. Portable AnyEvent 356presence is undefined and you cannot rely on them. Portable AnyEvent
309callbacks cannot use arguments passed to signal watcher callbacks. 357callbacks cannot use arguments passed to signal watcher callbacks.
310 358
326=head2 CHILD PROCESS WATCHERS 374=head2 CHILD PROCESS WATCHERS
327 375
328You can also watch on a child process exit and catch its exit status. 376You can also watch on a child process exit and catch its exit status.
329 377
330The child process is specified by the C<pid> argument (if set to C<0>, it 378The child process is specified by the C<pid> argument (if set to C<0>, it
331watches for any child process exit). The watcher will trigger as often 379watches for any child process exit). The watcher will triggered only when
332as status change for the child are received. This works by installing a 380the child process has finished and an exit status is available, not on
333signal handler for C<SIGCHLD>. The callback will be called with the pid 381any trace events (stopped/continued).
334and exit status (as returned by waitpid), so unlike other watcher types, 382
335you I<can> rely on child watcher callback arguments. 383The callback will be called with the pid and exit status (as returned by
384waitpid), so unlike other watcher types, you I<can> rely on child watcher
385callback arguments.
386
387This watcher type works by installing a signal handler for C<SIGCHLD>,
388and since it cannot be shared, nothing else should use SIGCHLD or reap
389random child processes (waiting for specific child processes, e.g. inside
390C<system>, is just fine).
336 391
337There is a slight catch to child watchers, however: you usually start them 392There is a slight catch to child watchers, however: you usually start them
338I<after> the child process was created, and this means the process could 393I<after> the child process was created, and this means the process could
339have exited already (and no SIGCHLD will be sent anymore). 394have exited already (and no SIGCHLD will be sent anymore).
340 395
346AnyEvent program, you I<have> to create at least one watcher before you 401AnyEvent program, you I<have> to create at least one watcher before you
347C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 402C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
348 403
349Example: fork a process and wait for it 404Example: fork a process and wait for it
350 405
351 my $done = AnyEvent->condvar; 406 my $done = AnyEvent->condvar;
352 407
353 my $pid = fork or exit 5; 408 my $pid = fork or exit 5;
354 409
355 my $w = AnyEvent->child ( 410 my $w = AnyEvent->child (
356 pid => $pid, 411 pid => $pid,
357 cb => sub { 412 cb => sub {
358 my ($pid, $status) = @_; 413 my ($pid, $status) = @_;
359 warn "pid $pid exited with status $status"; 414 warn "pid $pid exited with status $status";
360 $done->send; 415 $done->send;
361 }, 416 },
362 ); 417 );
363 418
364 # do something else, then wait for process exit 419 # do something else, then wait for process exit
365 $done->recv; 420 $done->recv;
421
422=head2 IDLE WATCHERS
423
424Sometimes there is a need to do something, but it is not so important
425to do it instantly, but only when there is nothing better to do. This
426"nothing better to do" is usually defined to be "no other events need
427attention by the event loop".
428
429Idle watchers ideally get invoked when the event loop has nothing
430better to do, just before it would block the process to wait for new
431events. Instead of blocking, the idle watcher is invoked.
432
433Most event loops unfortunately do not really support idle watchers (only
434EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
435will simply call the callback "from time to time".
436
437Example: read lines from STDIN, but only process them when the
438program is otherwise idle:
439
440 my @lines; # read data
441 my $idle_w;
442 my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
443 push @lines, scalar <STDIN>;
444
445 # start an idle watcher, if not already done
446 $idle_w ||= AnyEvent->idle (cb => sub {
447 # handle only one line, when there are lines left
448 if (my $line = shift @lines) {
449 print "handled when idle: $line";
450 } else {
451 # otherwise disable the idle watcher again
452 undef $idle_w;
453 }
454 });
455 });
366 456
367=head2 CONDITION VARIABLES 457=head2 CONDITION VARIABLES
368 458
369If you are familiar with some event loops you will know that all of them 459If you are familiar with some event loops you will know that all of them
370require you to run some blocking "loop", "run" or similar function that 460require you to run some blocking "loop", "run" or similar function that
376The instrument to do that is called a "condition variable", so called 466The instrument to do that is called a "condition variable", so called
377because they represent a condition that must become true. 467because they represent a condition that must become true.
378 468
379Condition variables can be created by calling the C<< AnyEvent->condvar 469Condition variables can be created by calling the C<< AnyEvent->condvar
380>> method, usually without arguments. The only argument pair allowed is 470>> method, usually without arguments. The only argument pair allowed is
471
381C<cb>, which specifies a callback to be called when the condition variable 472C<cb>, which specifies a callback to be called when the condition variable
382becomes true. 473becomes true, with the condition variable as the first argument (but not
474the results).
383 475
384After creation, the condition variable is "false" until it becomes "true" 476After creation, the condition variable is "false" until it becomes "true"
385by calling the C<send> method (or calling the condition variable as if it 477by calling the C<send> method (or calling the condition variable as if it
386were a callback, read about the caveats in the description for the C<< 478were a callback, read about the caveats in the description for the C<<
387->send >> method). 479->send >> method).
443 535
444 my $done = AnyEvent->condvar; 536 my $done = AnyEvent->condvar;
445 my $delay = AnyEvent->timer (after => 5, cb => $done); 537 my $delay = AnyEvent->timer (after => 5, cb => $done);
446 $done->recv; 538 $done->recv;
447 539
540Example: Imagine an API that returns a condvar and doesn't support
541callbacks. This is how you make a synchronous call, for example from
542the main program:
543
544 use AnyEvent::CouchDB;
545
546 ...
547
548 my @info = $couchdb->info->recv;
549
550And this is how you would just ste a callback to be called whenever the
551results are available:
552
553 $couchdb->info->cb (sub {
554 my @info = $_[0]->recv;
555 });
556
448=head3 METHODS FOR PRODUCERS 557=head3 METHODS FOR PRODUCERS
449 558
450These methods should only be used by the producing side, i.e. the 559These methods should only be used by the producing side, i.e. the
451code/module that eventually sends the signal. Note that it is also 560code/module that eventually sends the signal. Note that it is also
452the producer side which creates the condvar in most cases, but it isn't 561the producer side which creates the condvar in most cases, but it isn't
585=item $bool = $cv->ready 694=item $bool = $cv->ready
586 695
587Returns true when the condition is "true", i.e. whether C<send> or 696Returns true when the condition is "true", i.e. whether C<send> or
588C<croak> have been called. 697C<croak> have been called.
589 698
590=item $cb = $cv->cb ([new callback]) 699=item $cb = $cv->cb ($cb->($cv))
591 700
592This is a mutator function that returns the callback set and optionally 701This is a mutator function that returns the callback set and optionally
593replaces it before doing so. 702replaces it before doing so.
594 703
595The callback will be called when the condition becomes "true", i.e. when 704The callback will be called when the condition becomes "true", i.e. when
596C<send> or C<croak> are called. Calling C<recv> inside the callback 705C<send> or C<croak> are called, with the only argument being the condition
597or at any later time is guaranteed not to block. 706variable itself. Calling C<recv> inside the callback or at any later time
707is guaranteed not to block.
598 708
599=back 709=back
600 710
601=head1 GLOBAL VARIABLES AND FUNCTIONS 711=head1 GLOBAL VARIABLES AND FUNCTIONS
602 712
731=item L<AnyEvent::Util> 841=item L<AnyEvent::Util>
732 842
733Contains various utility functions that replace often-used but blocking 843Contains various utility functions that replace often-used but blocking
734functions such as C<inet_aton> by event-/callback-based versions. 844functions such as C<inet_aton> by event-/callback-based versions.
735 845
736=item L<AnyEvent::Handle>
737
738Provide read and write buffers and manages watchers for reads and writes.
739
740=item L<AnyEvent::Socket> 846=item L<AnyEvent::Socket>
741 847
742Provides various utility functions for (internet protocol) sockets, 848Provides various utility functions for (internet protocol) sockets,
743addresses and name resolution. Also functions to create non-blocking tcp 849addresses and name resolution. Also functions to create non-blocking tcp
744connections or tcp servers, with IPv6 and SRV record support and more. 850connections or tcp servers, with IPv6 and SRV record support and more.
745 851
852=item L<AnyEvent::Handle>
853
854Provide read and write buffers, manages watchers for reads and writes,
855supports raw and formatted I/O, I/O queued and fully transparent and
856non-blocking SSL/TLS.
857
746=item L<AnyEvent::DNS> 858=item L<AnyEvent::DNS>
747 859
748Provides rich asynchronous DNS resolver capabilities. 860Provides rich asynchronous DNS resolver capabilities.
749 861
862=item L<AnyEvent::HTTP>
863
864A simple-to-use HTTP library that is capable of making a lot of concurrent
865HTTP requests.
866
750=item L<AnyEvent::HTTPD> 867=item L<AnyEvent::HTTPD>
751 868
752Provides a simple web application server framework. 869Provides a simple web application server framework.
753 870
754=item L<AnyEvent::FastPing> 871=item L<AnyEvent::FastPing>
755 872
756The fastest ping in the west. 873The fastest ping in the west.
757 874
875=item L<AnyEvent::DBI>
876
877Executes L<DBI> requests asynchronously in a proxy process.
878
879=item L<AnyEvent::AIO>
880
881Truly asynchronous I/O, should be in the toolbox of every event
882programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
883together.
884
885=item L<AnyEvent::BDB>
886
887Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
888L<BDB> and AnyEvent together.
889
890=item L<AnyEvent::GPSD>
891
892A non-blocking interface to gpsd, a daemon delivering GPS information.
893
894=item L<AnyEvent::IGS>
895
896A non-blocking interface to the Internet Go Server protocol (used by
897L<App::IGS>).
898
758=item L<Net::IRC3> 899=item L<AnyEvent::IRC>
759 900
760AnyEvent based IRC client module family. 901AnyEvent based IRC client module family (replacing the older Net::IRC3).
761 902
762=item L<Net::XMPP2> 903=item L<Net::XMPP2>
763 904
764AnyEvent based XMPP (Jabber protocol) module family. 905AnyEvent based XMPP (Jabber protocol) module family.
765 906
774 915
775=item L<Coro> 916=item L<Coro>
776 917
777Has special support for AnyEvent via L<Coro::AnyEvent>. 918Has special support for AnyEvent via L<Coro::AnyEvent>.
778 919
779=item L<AnyEvent::AIO>, L<IO::AIO>
780
781Truly asynchronous I/O, should be in the toolbox of every event
782programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
783together.
784
785=item L<AnyEvent::BDB>, L<BDB>
786
787Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
788IO::AIO and AnyEvent together.
789
790=item L<IO::Lambda> 920=item L<IO::Lambda>
791 921
792The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 922The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
793 923
794=back 924=back
796=cut 926=cut
797 927
798package AnyEvent; 928package AnyEvent;
799 929
800no warnings; 930no warnings;
801use strict; 931use strict qw(vars subs);
802 932
803use Carp; 933use Carp;
804 934
805our $VERSION = '4.05'; 935our $VERSION = 4.41;
806our $MODEL; 936our $MODEL;
807 937
808our $AUTOLOAD; 938our $AUTOLOAD;
809our @ISA; 939our @ISA;
810 940
842 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 972 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
843 [Wx:: => AnyEvent::Impl::POE::], 973 [Wx:: => AnyEvent::Impl::POE::],
844 [Prima:: => AnyEvent::Impl::POE::], 974 [Prima:: => AnyEvent::Impl::POE::],
845); 975);
846 976
847our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 977our %method = map +($_ => 1),
978 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
848 979
849our @post_detect; 980our @post_detect;
850 981
851sub post_detect(&) { 982sub post_detect(&) {
852 my ($cb) = @_; 983 my ($cb) = @_;
857 1 988 1
858 } else { 989 } else {
859 push @post_detect, $cb; 990 push @post_detect, $cb;
860 991
861 defined wantarray 992 defined wantarray
862 ? bless \$cb, "AnyEvent::Util::PostDetect" 993 ? bless \$cb, "AnyEvent::Util::postdetect"
863 : () 994 : ()
864 } 995 }
865} 996}
866 997
867sub AnyEvent::Util::PostDetect::DESTROY { 998sub AnyEvent::Util::postdetect::DESTROY {
868 @post_detect = grep $_ != ${$_[0]}, @post_detect; 999 @post_detect = grep $_ != ${$_[0]}, @post_detect;
869} 1000}
870 1001
871sub detect() { 1002sub detect() {
872 unless ($MODEL) { 1003 unless ($MODEL) {
909 last; 1040 last;
910 } 1041 }
911 } 1042 }
912 1043
913 $MODEL 1044 $MODEL
914 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1045 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
915 } 1046 }
916 } 1047 }
917 1048
1049 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1050
918 unshift @ISA, $MODEL; 1051 unshift @ISA, $MODEL;
919 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1052
1053 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
920 1054
921 (shift @post_detect)->() while @post_detect; 1055 (shift @post_detect)->() while @post_detect;
922 } 1056 }
923 1057
924 $MODEL 1058 $MODEL
934 1068
935 my $class = shift; 1069 my $class = shift;
936 $class->$func (@_); 1070 $class->$func (@_);
937} 1071}
938 1072
1073# utility function to dup a filehandle. this is used by many backends
1074# to support binding more than one watcher per filehandle (they usually
1075# allow only one watcher per fd, so we dup it to get a different one).
1076sub _dupfh($$$$) {
1077 my ($poll, $fh, $r, $w) = @_;
1078
1079 # cygwin requires the fh mode to be matching, unix doesn't
1080 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1081 : $poll eq "w" ? ($w, ">")
1082 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083
1084 open my $fh2, "$mode&" . fileno $fh
1085 or die "cannot dup() filehandle: $!,";
1086
1087 # we assume CLOEXEC is already set by perl in all important cases
1088
1089 ($fh2, $rw)
1090}
1091
939package AnyEvent::Base; 1092package AnyEvent::Base;
940 1093
941# default implementation for now and time 1094# default implementations for many methods
942 1095
943use Time::HiRes (); 1096BEGIN {
1097 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1098 *_time = \&Time::HiRes::time;
1099 # if (eval "use POSIX (); (POSIX::times())...
1100 } else {
1101 *_time = sub { time }; # epic fail
1102 }
1103}
944 1104
945sub time { Time::HiRes::time } 1105sub time { _time }
946sub now { Time::HiRes::time } 1106sub now { _time }
1107sub now_update { }
947 1108
948# default implementation for ->condvar 1109# default implementation for ->condvar
949 1110
950sub condvar { 1111sub condvar {
951 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1112 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
952} 1113}
953 1114
954# default implementation for ->signal 1115# default implementation for ->signal
955 1116
956our %SIG_CB; 1117our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1118
1119sub _signal_exec {
1120 sysread $SIGPIPE_R, my $dummy, 4;
1121
1122 while (%SIG_EV) {
1123 for (keys %SIG_EV) {
1124 delete $SIG_EV{$_};
1125 $_->() for values %{ $SIG_CB{$_} || {} };
1126 }
1127 }
1128}
957 1129
958sub signal { 1130sub signal {
959 my (undef, %arg) = @_; 1131 my (undef, %arg) = @_;
960 1132
1133 unless ($SIGPIPE_R) {
1134 require Fcntl;
1135
1136 if (AnyEvent::WIN32) {
1137 require AnyEvent::Util;
1138
1139 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1140 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1141 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1142 } else {
1143 pipe $SIGPIPE_R, $SIGPIPE_W;
1144 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1145 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1146 }
1147
1148 $SIGPIPE_R
1149 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1150
1151 # not strictly required, as $^F is normally 2, but let's make sure...
1152 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154
1155 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1156 }
1157
961 my $signal = uc $arg{signal} 1158 my $signal = uc $arg{signal}
962 or Carp::croak "required option 'signal' is missing"; 1159 or Carp::croak "required option 'signal' is missing";
963 1160
964 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1161 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
965 $SIG{$signal} ||= sub { 1162 $SIG{$signal} ||= sub {
966 $_->() for values %{ $SIG_CB{$signal} || {} }; 1163 local $!;
1164 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1165 undef $SIG_EV{$signal};
967 }; 1166 };
968 1167
969 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1168 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
970} 1169}
971 1170
972sub AnyEvent::Base::Signal::DESTROY { 1171sub AnyEvent::Base::signal::DESTROY {
973 my ($signal, $cb) = @{$_[0]}; 1172 my ($signal, $cb) = @{$_[0]};
974 1173
975 delete $SIG_CB{$signal}{$cb}; 1174 delete $SIG_CB{$signal}{$cb};
976 1175
977 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; 1176 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
1018 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1217 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1019 # child could be a zombie already, so make at least one round 1218 # child could be a zombie already, so make at least one round
1020 &_sigchld; 1219 &_sigchld;
1021 } 1220 }
1022 1221
1023 bless [$pid, $arg{cb}], "AnyEvent::Base::Child" 1222 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1024} 1223}
1025 1224
1026sub AnyEvent::Base::Child::DESTROY { 1225sub AnyEvent::Base::child::DESTROY {
1027 my ($pid, $cb) = @{$_[0]}; 1226 my ($pid, $cb) = @{$_[0]};
1028 1227
1029 delete $PID_CB{$pid}{$cb}; 1228 delete $PID_CB{$pid}{$cb};
1030 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1229 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1031 1230
1032 undef $CHLD_W unless keys %PID_CB; 1231 undef $CHLD_W unless keys %PID_CB;
1232}
1233
1234# idle emulation is done by simply using a timer, regardless
1235# of whether the proces sis idle or not, and not letting
1236# the callback use more than 50% of the time.
1237sub idle {
1238 my (undef, %arg) = @_;
1239
1240 my ($cb, $w, $rcb) = $arg{cb};
1241
1242 $rcb = sub {
1243 if ($cb) {
1244 $w = _time;
1245 &$cb;
1246 $w = _time - $w;
1247
1248 # never use more then 50% of the time for the idle watcher,
1249 # within some limits
1250 $w = 0.0001 if $w < 0.0001;
1251 $w = 5 if $w > 5;
1252
1253 $w = AnyEvent->timer (after => $w, cb => $rcb);
1254 } else {
1255 # clean up...
1256 undef $w;
1257 undef $rcb;
1258 }
1259 };
1260
1261 $w = AnyEvent->timer (after => 0.05, cb => $rcb);
1262
1263 bless \\$cb, "AnyEvent::Base::idle"
1264}
1265
1266sub AnyEvent::Base::idle::DESTROY {
1267 undef $${$_[0]};
1033} 1268}
1034 1269
1035package AnyEvent::CondVar; 1270package AnyEvent::CondVar;
1036 1271
1037our @ISA = AnyEvent::CondVar::Base::; 1272our @ISA = AnyEvent::CondVar::Base::;
1089} 1324}
1090 1325
1091# undocumented/compatibility with pre-3.4 1326# undocumented/compatibility with pre-3.4
1092*broadcast = \&send; 1327*broadcast = \&send;
1093*wait = \&_wait; 1328*wait = \&_wait;
1329
1330=head1 ERROR AND EXCEPTION HANDLING
1331
1332In general, AnyEvent does not do any error handling - it relies on the
1333caller to do that if required. The L<AnyEvent::Strict> module (see also
1334the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
1335checking of all AnyEvent methods, however, which is highly useful during
1336development.
1337
1338As for exception handling (i.e. runtime errors and exceptions thrown while
1339executing a callback), this is not only highly event-loop specific, but
1340also not in any way wrapped by this module, as this is the job of the main
1341program.
1342
1343The pure perl event loop simply re-throws the exception (usually
1344within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
1345$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1346so on.
1347
1348=head1 ENVIRONMENT VARIABLES
1349
1350The following environment variables are used by this module or its
1351submodules:
1352
1353=over 4
1354
1355=item C<PERL_ANYEVENT_VERBOSE>
1356
1357By default, AnyEvent will be completely silent except in fatal
1358conditions. You can set this environment variable to make AnyEvent more
1359talkative.
1360
1361When set to C<1> or higher, causes AnyEvent to warn about unexpected
1362conditions, such as not being able to load the event model specified by
1363C<PERL_ANYEVENT_MODEL>.
1364
1365When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1366model it chooses.
1367
1368=item C<PERL_ANYEVENT_STRICT>
1369
1370AnyEvent does not do much argument checking by default, as thorough
1371argument checking is very costly. Setting this variable to a true value
1372will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1373check the arguments passed to most method calls. If it finds any problems
1374it will croak.
1375
1376In other words, enables "strict" mode.
1377
1378Unlike C<use strict>, it is definitely recommended ot keep it off in
1379production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1380developing programs can be very useful, however.
1381
1382=item C<PERL_ANYEVENT_MODEL>
1383
1384This can be used to specify the event model to be used by AnyEvent, before
1385auto detection and -probing kicks in. It must be a string consisting
1386entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1387and the resulting module name is loaded and if the load was successful,
1388used as event model. If it fails to load AnyEvent will proceed with
1389auto detection and -probing.
1390
1391This functionality might change in future versions.
1392
1393For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1394could start your program like this:
1395
1396 PERL_ANYEVENT_MODEL=Perl perl ...
1397
1398=item C<PERL_ANYEVENT_PROTOCOLS>
1399
1400Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1401for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1402of auto probing).
1403
1404Must be set to a comma-separated list of protocols or address families,
1405current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1406used, and preference will be given to protocols mentioned earlier in the
1407list.
1408
1409This variable can effectively be used for denial-of-service attacks
1410against local programs (e.g. when setuid), although the impact is likely
1411small, as the program has to handle conenction and other failures anyways.
1412
1413Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1414but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1415- only support IPv4, never try to resolve or contact IPv6
1416addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1417IPv6, but prefer IPv6 over IPv4.
1418
1419=item C<PERL_ANYEVENT_EDNS0>
1420
1421Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1422for DNS. This extension is generally useful to reduce DNS traffic, but
1423some (broken) firewalls drop such DNS packets, which is why it is off by
1424default.
1425
1426Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1427EDNS0 in its DNS requests.
1428
1429=item C<PERL_ANYEVENT_MAX_FORKS>
1430
1431The maximum number of child processes that C<AnyEvent::Util::fork_call>
1432will create in parallel.
1433
1434=back
1094 1435
1095=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1436=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1096 1437
1097This is an advanced topic that you do not normally need to use AnyEvent in 1438This is an advanced topic that you do not normally need to use AnyEvent in
1098a module. This section is only of use to event loop authors who want to 1439a module. This section is only of use to event loop authors who want to
1132 1473
1133I<rxvt-unicode> also cheats a bit by not providing blocking access to 1474I<rxvt-unicode> also cheats a bit by not providing blocking access to
1134condition variables: code blocking while waiting for a condition will 1475condition variables: code blocking while waiting for a condition will
1135C<die>. This still works with most modules/usages, and blocking calls must 1476C<die>. This still works with most modules/usages, and blocking calls must
1136not be done in an interactive application, so it makes sense. 1477not be done in an interactive application, so it makes sense.
1137
1138=head1 ENVIRONMENT VARIABLES
1139
1140The following environment variables are used by this module:
1141
1142=over 4
1143
1144=item C<PERL_ANYEVENT_VERBOSE>
1145
1146By default, AnyEvent will be completely silent except in fatal
1147conditions. You can set this environment variable to make AnyEvent more
1148talkative.
1149
1150When set to C<1> or higher, causes AnyEvent to warn about unexpected
1151conditions, such as not being able to load the event model specified by
1152C<PERL_ANYEVENT_MODEL>.
1153
1154When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1155model it chooses.
1156
1157=item C<PERL_ANYEVENT_MODEL>
1158
1159This can be used to specify the event model to be used by AnyEvent, before
1160auto detection and -probing kicks in. It must be a string consisting
1161entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1162and the resulting module name is loaded and if the load was successful,
1163used as event model. If it fails to load AnyEvent will proceed with
1164auto detection and -probing.
1165
1166This functionality might change in future versions.
1167
1168For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1169could start your program like this:
1170
1171 PERL_ANYEVENT_MODEL=Perl perl ...
1172
1173=item C<PERL_ANYEVENT_PROTOCOLS>
1174
1175Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1176for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1177of auto probing).
1178
1179Must be set to a comma-separated list of protocols or address families,
1180current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1181used, and preference will be given to protocols mentioned earlier in the
1182list.
1183
1184This variable can effectively be used for denial-of-service attacks
1185against local programs (e.g. when setuid), although the impact is likely
1186small, as the program has to handle connection errors already-
1187
1188Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1189but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1190- only support IPv4, never try to resolve or contact IPv6
1191addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1192IPv6, but prefer IPv6 over IPv4.
1193
1194=item C<PERL_ANYEVENT_EDNS0>
1195
1196Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1197for DNS. This extension is generally useful to reduce DNS traffic, but
1198some (broken) firewalls drop such DNS packets, which is why it is off by
1199default.
1200
1201Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1202EDNS0 in its DNS requests.
1203
1204=item C<PERL_ANYEVENT_MAX_FORKS>
1205
1206The maximum number of child processes that C<AnyEvent::Util::fork_call>
1207will create in parallel.
1208
1209=back
1210 1478
1211=head1 EXAMPLE PROGRAM 1479=head1 EXAMPLE PROGRAM
1212 1480
1213The following program uses an I/O watcher to read data from STDIN, a timer 1481The following program uses an I/O watcher to read data from STDIN, a timer
1214to display a message once per second, and a condition variable to quit the 1482to display a message once per second, and a condition variable to quit the
1408watcher. 1676watcher.
1409 1677
1410=head3 Results 1678=head3 Results
1411 1679
1412 name watchers bytes create invoke destroy comment 1680 name watchers bytes create invoke destroy comment
1413 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 1681 EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1414 EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers 1682 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1415 CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal 1683 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1416 Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation 1684 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1417 Event/Event 16000 516 31.88 31.30 0.85 Event native interface 1685 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1418 Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers 1686 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1419 Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour 1687 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1420 Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers 1688 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1421 POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event 1689 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1422 POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select 1690 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1423 1691
1424=head3 Discussion 1692=head3 Discussion
1425 1693
1426The benchmark does I<not> measure scalability of the event loop very 1694The benchmark does I<not> measure scalability of the event loop very
1427well. For example, a select-based event loop (such as the pure perl one) 1695well. For example, a select-based event loop (such as the pure perl one)
1629watchers, as the management overhead dominates. 1897watchers, as the management overhead dominates.
1630 1898
1631=back 1899=back
1632 1900
1633 1901
1902=head1 SIGNALS
1903
1904AnyEvent currently installs handlers for these signals:
1905
1906=over 4
1907
1908=item SIGCHLD
1909
1910A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1911emulation for event loops that do not support them natively. Also, some
1912event loops install a similar handler.
1913
1914=item SIGPIPE
1915
1916A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1917when AnyEvent gets loaded.
1918
1919The rationale for this is that AnyEvent users usually do not really depend
1920on SIGPIPE delivery (which is purely an optimisation for shell use, or
1921badly-written programs), but C<SIGPIPE> can cause spurious and rare
1922program exits as a lot of people do not expect C<SIGPIPE> when writing to
1923some random socket.
1924
1925The rationale for installing a no-op handler as opposed to ignoring it is
1926that this way, the handler will be restored to defaults on exec.
1927
1928Feel free to install your own handler, or reset it to defaults.
1929
1930=back
1931
1932=cut
1933
1934$SIG{PIPE} = sub { }
1935 unless defined $SIG{PIPE};
1936
1937
1634=head1 FORK 1938=head1 FORK
1635 1939
1636Most event libraries are not fork-safe. The ones who are usually are 1940Most event libraries are not fork-safe. The ones who are usually are
1637because they rely on inefficient but fork-safe C<select> or C<poll> 1941because they rely on inefficient but fork-safe C<select> or C<poll>
1638calls. Only L<EV> is fully fork-aware. 1942calls. Only L<EV> is fully fork-aware.
1651specified in the variable. 1955specified in the variable.
1652 1956
1653You can make AnyEvent completely ignore this variable by deleting it 1957You can make AnyEvent completely ignore this variable by deleting it
1654before the first watcher gets created, e.g. with a C<BEGIN> block: 1958before the first watcher gets created, e.g. with a C<BEGIN> block:
1655 1959
1656 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1960 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1657 1961
1658 use AnyEvent; 1962 use AnyEvent;
1659 1963
1660Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1964Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1661be used to probe what backend is used and gain other information (which is 1965be used to probe what backend is used and gain other information (which is
1662probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1966probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1967$ENV{PERL_ANYEGENT_STRICT}.
1968
1969
1970=head1 BUGS
1971
1972Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1973to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1974and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1975memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1976pronounced).
1663 1977
1664 1978
1665=head1 SEE ALSO 1979=head1 SEE ALSO
1666 1980
1667Utility functions: L<AnyEvent::Util>. 1981Utility functions: L<AnyEvent::Util>.
1684Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 1998Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1685 1999
1686 2000
1687=head1 AUTHOR 2001=head1 AUTHOR
1688 2002
1689 Marc Lehmann <schmorp@schmorp.de> 2003 Marc Lehmann <schmorp@schmorp.de>
1690 http://home.schmorp.de/ 2004 http://home.schmorp.de/
1691 2005
1692=cut 2006=cut
1693 2007
16941 20081
1695 2009

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