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1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - the DBI of event loop programming 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt 5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6and POE are various supported event loops/environments. 6FLTK and POE are various supported event loops/environments.
7 7
8=head1 SYNOPSIS 8=head1 SYNOPSIS
9 9
10 use AnyEvent; 10 use AnyEvent;
11 11
12 # if you prefer function calls, look at the AE manpage for
13 # an alternative API.
14
12 # file descriptor readable 15 # file handle or descriptor readable
13 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); 16 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14 17
15 # one-shot or repeating timers 18 # one-shot or repeating timers
16 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); 19 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... 20 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18 21
19 print AnyEvent->now; # prints current event loop time 22 print AnyEvent->now; # prints current event loop time
20 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. 23 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21 24
22 # POSIX signal 25 # POSIX signal
43in a tutorial or some gentle introduction, have a look at the 46in a tutorial or some gentle introduction, have a look at the
44L<AnyEvent::Intro> manpage. 47L<AnyEvent::Intro> manpage.
45 48
46=head1 SUPPORT 49=head1 SUPPORT
47 50
51An FAQ document is available as L<AnyEvent::FAQ>.
52
48There is a mailinglist for discussing all things AnyEvent, and an IRC 53There also is a mailinglist for discussing all things AnyEvent, and an IRC
49channel, too. 54channel, too.
50 55
51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software 56See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52Repository>, at L<http://anyevent.schmorp.de>, for more info. 57Repository>, at L<http://anyevent.schmorp.de>, for more info.
53 58
73module users into the same thing by forcing them to use the same event 78module users into the same thing by forcing them to use the same event
74model you use. 79model you use.
75 80
76For modules like POE or IO::Async (which is a total misnomer as it is 81For modules like POE or IO::Async (which is a total misnomer as it is
77actually doing all I/O I<synchronously>...), using them in your module is 82actually doing all I/O I<synchronously>...), using them in your module is
78like joining a cult: After you joined, you are dependent on them and you 83like joining a cult: After you join, you are dependent on them and you
79cannot use anything else, as they are simply incompatible to everything 84cannot use anything else, as they are simply incompatible to everything
80that isn't them. What's worse, all the potential users of your 85that isn't them. What's worse, all the potential users of your
81module are I<also> forced to use the same event loop you use. 86module are I<also> forced to use the same event loop you use.
82 87
83AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 88AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84fine. AnyEvent + Tk works fine etc. etc. but none of these work together 89fine. AnyEvent + Tk works fine etc. etc. but none of these work together
85with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if 90with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
86your module uses one of those, every user of your module has to use it, 91uses one of those, every user of your module has to use it, too. But if
87too. But if your module uses AnyEvent, it works transparently with all 92your module uses AnyEvent, it works transparently with all event models it
88event models it supports (including stuff like IO::Async, as long as those 93supports (including stuff like IO::Async, as long as those use one of the
89use one of the supported event loops. It is trivial to add new event loops 94supported event loops. It is easy to add new event loops to AnyEvent, too,
90to AnyEvent, too, so it is future-proof). 95so it is future-proof).
91 96
92In addition to being free of having to use I<the one and only true event 97In addition to being free of having to use I<the one and only true event
93model>, AnyEvent also is free of bloat and policy: with POE or similar 98model>, AnyEvent also is free of bloat and policy: with POE or similar
94modules, you get an enormous amount of code and strict rules you have to 99modules, you get an enormous amount of code and strict rules you have to
95follow. AnyEvent, on the other hand, is lean and up to the point, by only 100follow. AnyEvent, on the other hand, is lean and to the point, by only
96offering the functionality that is necessary, in as thin as a wrapper as 101offering the functionality that is necessary, in as thin as a wrapper as
97technically possible. 102technically possible.
98 103
99Of course, AnyEvent comes with a big (and fully optional!) toolbox 104Of course, AnyEvent comes with a big (and fully optional!) toolbox
100of useful functionality, such as an asynchronous DNS resolver, 100% 105of useful functionality, such as an asynchronous DNS resolver, 100%
106useful) and you want to force your users to use the one and only event 111useful) and you want to force your users to use the one and only event
107model, you should I<not> use this module. 112model, you should I<not> use this module.
108 113
109=head1 DESCRIPTION 114=head1 DESCRIPTION
110 115
111L<AnyEvent> provides an identical interface to multiple event loops. This 116L<AnyEvent> provides a uniform interface to various event loops. This
112allows module authors to utilise an event loop without forcing module 117allows module authors to use event loop functionality without forcing
113users to use the same event loop (as only a single event loop can coexist 118module users to use a specific event loop implementation (since more
114peacefully at any one time). 119than one event loop cannot coexist peacefully).
115 120
116The interface itself is vaguely similar, but not identical to the L<Event> 121The interface itself is vaguely similar, but not identical to the L<Event>
117module. 122module.
118 123
119During the first call of any watcher-creation method, the module tries 124During the first call of any watcher-creation method, the module tries
120to detect the currently loaded event loop by probing whether one of the 125to detect the currently loaded event loop by probing whether one of the
121following modules is already loaded: L<EV>, 126following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
122L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, 127L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
123L<POE>. The first one found is used. If none are found, the module tries 128found is used. If none are detected, the module tries to load the first
124to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl 129four modules in the order given; but note that if L<EV> is not
125adaptor should always succeed) in the order given. The first one that can 130available, the pure-perl L<AnyEvent::Loop> should always work, so
126be successfully loaded will be used. If, after this, still none could be 131the other two are not normally tried.
127found, AnyEvent will fall back to a pure-perl event loop, which is not
128very efficient, but should work everywhere.
129 132
130Because AnyEvent first checks for modules that are already loaded, loading 133Because AnyEvent first checks for modules that are already loaded, loading
131an event model explicitly before first using AnyEvent will likely make 134an event model explicitly before first using AnyEvent will likely make
132that model the default. For example: 135that model the default. For example:
133 136
135 use AnyEvent; 138 use AnyEvent;
136 139
137 # .. AnyEvent will likely default to Tk 140 # .. AnyEvent will likely default to Tk
138 141
139The I<likely> means that, if any module loads another event model and 142The I<likely> means that, if any module loads another event model and
140starts using it, all bets are off. Maybe you should tell their authors to 143starts using it, all bets are off - this case should be very rare though,
141use AnyEvent so their modules work together with others seamlessly... 144as very few modules hardcode event loops without announcing this very
145loudly.
142 146
143The pure-perl implementation of AnyEvent is called 147The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
144C<AnyEvent::Impl::Perl>. Like other event modules you can load it 148other event modules you can load it explicitly and enjoy the high
145explicitly and enjoy the high availability of that event loop :) 149availability of that event loop :)
146 150
147=head1 WATCHERS 151=head1 WATCHERS
148 152
149AnyEvent has the central concept of a I<watcher>, which is an object that 153AnyEvent has the central concept of a I<watcher>, which is an object that
150stores relevant data for each kind of event you are waiting for, such as 154stores relevant data for each kind of event you are waiting for, such as
155callback when the event occurs (of course, only when the event model 159callback when the event occurs (of course, only when the event model
156is in control). 160is in control).
157 161
158Note that B<callbacks must not permanently change global variables> 162Note that B<callbacks must not permanently change global variables>
159potentially in use by the event loop (such as C<$_> or C<$[>) and that B<< 163potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
160callbacks must not C<die> >>. The former is good programming practise in 164callbacks must not C<die> >>. The former is good programming practice in
161Perl and the latter stems from the fact that exception handling differs 165Perl and the latter stems from the fact that exception handling differs
162widely between event loops. 166widely between event loops.
163 167
164To disable the watcher you have to destroy it (e.g. by setting the 168To disable a watcher you have to destroy it (e.g. by setting the
165variable you store it in to C<undef> or otherwise deleting all references 169variable you store it in to C<undef> or otherwise deleting all references
166to it). 170to it).
167 171
168All watchers are created by calling a method on the C<AnyEvent> class. 172All watchers are created by calling a method on the C<AnyEvent> class.
169 173
170Many watchers either are used with "recursion" (repeating timers for 174Many watchers either are used with "recursion" (repeating timers for
171example), or need to refer to their watcher object in other ways. 175example), or need to refer to their watcher object in other ways.
172 176
173An any way to achieve that is this pattern: 177One way to achieve that is this pattern:
174 178
175 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 179 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176 # you can use $w here, for example to undef it 180 # you can use $w here, for example to undef it
177 undef $w; 181 undef $w;
178 }); 182 });
210 214
211The I/O watcher might use the underlying file descriptor or a copy of it. 215The I/O watcher might use the underlying file descriptor or a copy of it.
212You must not close a file handle as long as any watcher is active on the 216You must not close a file handle as long as any watcher is active on the
213underlying file descriptor. 217underlying file descriptor.
214 218
215Some event loops issue spurious readyness notifications, so you should 219Some event loops issue spurious readiness notifications, so you should
216always use non-blocking calls when reading/writing from/to your file 220always use non-blocking calls when reading/writing from/to your file
217handles. 221handles.
218 222
219Example: wait for readability of STDIN, then read a line and disable the 223Example: wait for readability of STDIN, then read a line and disable the
220watcher. 224watcher.
244 248
245Although the callback might get passed parameters, their value and 249Although the callback might get passed parameters, their value and
246presence is undefined and you cannot rely on them. Portable AnyEvent 250presence is undefined and you cannot rely on them. Portable AnyEvent
247callbacks cannot use arguments passed to time watcher callbacks. 251callbacks cannot use arguments passed to time watcher callbacks.
248 252
249The callback will normally be invoked once only. If you specify another 253The callback will normally be invoked only once. If you specify another
250parameter, C<interval>, as a strictly positive number (> 0), then the 254parameter, C<interval>, as a strictly positive number (> 0), then the
251callback will be invoked regularly at that interval (in fractional 255callback will be invoked regularly at that interval (in fractional
252seconds) after the first invocation. If C<interval> is specified with a 256seconds) after the first invocation. If C<interval> is specified with a
253false value, then it is treated as if it were missing. 257false value, then it is treated as if it were not specified at all.
254 258
255The callback will be rescheduled before invoking the callback, but no 259The callback will be rescheduled before invoking the callback, but no
256attempt is done to avoid timer drift in most backends, so the interval is 260attempt is made to avoid timer drift in most backends, so the interval is
257only approximate. 261only approximate.
258 262
259Example: fire an event after 7.7 seconds. 263Example: fire an event after 7.7 seconds.
260 264
261 my $w = AnyEvent->timer (after => 7.7, cb => sub { 265 my $w = AnyEvent->timer (after => 7.7, cb => sub {
279 283
280While most event loops expect timers to specified in a relative way, they 284While most event loops expect timers to specified in a relative way, they
281use absolute time internally. This makes a difference when your clock 285use absolute time internally. This makes a difference when your clock
282"jumps", for example, when ntp decides to set your clock backwards from 286"jumps", for example, when ntp decides to set your clock backwards from
283the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to 287the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
284fire "after" a second might actually take six years to finally fire. 288fire "after a second" might actually take six years to finally fire.
285 289
286AnyEvent cannot compensate for this. The only event loop that is conscious 290AnyEvent cannot compensate for this. The only event loop that is conscious
287about these issues is L<EV>, which offers both relative (ev_timer, based 291of these issues is L<EV>, which offers both relative (ev_timer, based
288on true relative time) and absolute (ev_periodic, based on wallclock time) 292on true relative time) and absolute (ev_periodic, based on wallclock time)
289timers. 293timers.
290 294
291AnyEvent always prefers relative timers, if available, matching the 295AnyEvent always prefers relative timers, if available, matching the
292AnyEvent API. 296AnyEvent API.
314I<In almost all cases (in all cases if you don't care), this is the 318I<In almost all cases (in all cases if you don't care), this is the
315function to call when you want to know the current time.> 319function to call when you want to know the current time.>
316 320
317This function is also often faster then C<< AnyEvent->time >>, and 321This function is also often faster then C<< AnyEvent->time >>, and
318thus the preferred method if you want some timestamp (for example, 322thus the preferred method if you want some timestamp (for example,
319L<AnyEvent::Handle> uses this to update it's activity timeouts). 323L<AnyEvent::Handle> uses this to update its activity timeouts).
320 324
321The rest of this section is only of relevance if you try to be very exact 325The rest of this section is only of relevance if you try to be very exact
322with your timing, you can skip it without bad conscience. 326with your timing; you can skip it without a bad conscience.
323 327
324For a practical example of when these times differ, consider L<Event::Lib> 328For a practical example of when these times differ, consider L<Event::Lib>
325and L<EV> and the following set-up: 329and L<EV> and the following set-up:
326 330
327The event loop is running and has just invoked one of your callback at 331The event loop is running and has just invoked one of your callbacks at
328time=500 (assume no other callbacks delay processing). In your callback, 332time=500 (assume no other callbacks delay processing). In your callback,
329you wait a second by executing C<sleep 1> (blocking the process for a 333you wait a second by executing C<sleep 1> (blocking the process for a
330second) and then (at time=501) you create a relative timer that fires 334second) and then (at time=501) you create a relative timer that fires
331after three seconds. 335after three seconds.
332 336
352difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 356difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
353account. 357account.
354 358
355=item AnyEvent->now_update 359=item AnyEvent->now_update
356 360
357Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache 361Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
358the current time for each loop iteration (see the discussion of L<< 362time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
359AnyEvent->now >>, above). 363above).
360 364
361When a callback runs for a long time (or when the process sleeps), then 365When a callback runs for a long time (or when the process sleeps), then
362this "current" time will differ substantially from the real time, which 366this "current" time will differ substantially from the real time, which
363might affect timers and time-outs. 367might affect timers and time-outs.
364 368
365When this is the case, you can call this method, which will update the 369When this is the case, you can call this method, which will update the
366event loop's idea of "current time". 370event loop's idea of "current time".
371
372A typical example would be a script in a web server (e.g. C<mod_perl>) -
373when mod_perl executes the script, then the event loop will have the wrong
374idea about the "current time" (being potentially far in the past, when the
375script ran the last time). In that case you should arrange a call to C<<
376AnyEvent->now_update >> each time the web server process wakes up again
377(e.g. at the start of your script, or in a handler).
367 378
368Note that updating the time I<might> cause some events to be handled. 379Note that updating the time I<might> cause some events to be handled.
369 380
370=back 381=back
371 382
396 407
397Example: exit on SIGINT 408Example: exit on SIGINT
398 409
399 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 410 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
400 411
412=head3 Restart Behaviour
413
414While restart behaviour is up to the event loop implementation, most will
415not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
416pure perl implementation).
417
418=head3 Safe/Unsafe Signals
419
420Perl signals can be either "safe" (synchronous to opcode handling)
421or "unsafe" (asynchronous) - the former might delay signal delivery
422indefinitely, the latter might corrupt your memory.
423
424AnyEvent signal handlers are, in addition, synchronous to the event loop,
425i.e. they will not interrupt your running perl program but will only be
426called as part of the normal event handling (just like timer, I/O etc.
427callbacks, too).
428
401=head3 Signal Races, Delays and Workarounds 429=head3 Signal Races, Delays and Workarounds
402 430
403Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching 431Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
404callbacks to signals in a generic way, which is a pity, as you cannot 432attaching callbacks to signals in a generic way, which is a pity,
405do race-free signal handling in perl, requiring C libraries for 433as you cannot do race-free signal handling in perl, requiring
406this. AnyEvent will try to do it's best, which means in some cases, 434C libraries for this. AnyEvent will try to do its best, which
407signals will be delayed. The maximum time a signal might be delayed is 435means in some cases, signals will be delayed. The maximum time
408specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This 436a signal might be delayed is 10 seconds by default, but can
409variable can be changed only before the first signal watcher is created, 437be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
410and should be left alone otherwise. This variable determines how often 438C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
411AnyEvent polls for signals (in case a wake-up was missed). Higher values 439section for details.
412will cause fewer spurious wake-ups, which is better for power and CPU
413saving.
414 440
415All these problems can be avoided by installing the optional 441All these problems can be avoided by installing the optional
416L<Async::Interrupt> module, which works with most event loops. It will not 442L<Async::Interrupt> module, which works with most event loops. It will not
417work with inherently broken event loops such as L<Event> or L<Event::Lib> 443work with inherently broken event loops such as L<Event> or L<Event::Lib>
418(and not with L<POE> currently, as POE does it's own workaround with 444(and not with L<POE> currently). For those, you just have to suffer the
419one-second latency). For those, you just have to suffer the delays. 445delays.
420 446
421=head2 CHILD PROCESS WATCHERS 447=head2 CHILD PROCESS WATCHERS
422 448
423 $w = AnyEvent->child (pid => <process id>, cb => <callback>); 449 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
424 450
425You can also watch on a child process exit and catch its exit status. 451You can also watch for a child process exit and catch its exit status.
426 452
427The child process is specified by the C<pid> argument (one some backends, 453The child process is specified by the C<pid> argument (on some backends,
428using C<0> watches for any child process exit, on others this will 454using C<0> watches for any child process exit, on others this will
429croak). The watcher will be triggered only when the child process has 455croak). The watcher will be triggered only when the child process has
430finished and an exit status is available, not on any trace events 456finished and an exit status is available, not on any trace events
431(stopped/continued). 457(stopped/continued).
432 458
454thing in an AnyEvent program, you I<have> to create at least one 480thing in an AnyEvent program, you I<have> to create at least one
455watcher before you C<fork> the child (alternatively, you can call 481watcher before you C<fork> the child (alternatively, you can call
456C<AnyEvent::detect>). 482C<AnyEvent::detect>).
457 483
458As most event loops do not support waiting for child events, they will be 484As most event loops do not support waiting for child events, they will be
459emulated by AnyEvent in most cases, in which the latency and race problems 485emulated by AnyEvent in most cases, in which case the latency and race
460mentioned in the description of signal watchers apply. 486problems mentioned in the description of signal watchers apply.
461 487
462Example: fork a process and wait for it 488Example: fork a process and wait for it
463 489
464 my $done = AnyEvent->condvar; 490 my $done = AnyEvent->condvar;
465 491
479 505
480=head2 IDLE WATCHERS 506=head2 IDLE WATCHERS
481 507
482 $w = AnyEvent->idle (cb => <callback>); 508 $w = AnyEvent->idle (cb => <callback>);
483 509
484Sometimes there is a need to do something, but it is not so important 510This will repeatedly invoke the callback after the process becomes idle,
485to do it instantly, but only when there is nothing better to do. This 511until either the watcher is destroyed or new events have been detected.
486"nothing better to do" is usually defined to be "no other events need
487attention by the event loop".
488 512
489Idle watchers ideally get invoked when the event loop has nothing 513Idle watchers are useful when there is a need to do something, but it
490better to do, just before it would block the process to wait for new 514is not so important (or wise) to do it instantly. The callback will be
491events. Instead of blocking, the idle watcher is invoked. 515invoked only when there is "nothing better to do", which is usually
516defined as "all outstanding events have been handled and no new events
517have been detected". That means that idle watchers ideally get invoked
518when the event loop has just polled for new events but none have been
519detected. Instead of blocking to wait for more events, the idle watchers
520will be invoked.
492 521
493Most event loops unfortunately do not really support idle watchers (only 522Unfortunately, most event loops do not really support idle watchers (only
494EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent 523EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
495will simply call the callback "from time to time". 524will simply call the callback "from time to time".
496 525
497Example: read lines from STDIN, but only process them when the 526Example: read lines from STDIN, but only process them when the
498program is otherwise idle: 527program is otherwise idle:
526will actively watch for new events and call your callbacks. 555will actively watch for new events and call your callbacks.
527 556
528AnyEvent is slightly different: it expects somebody else to run the event 557AnyEvent is slightly different: it expects somebody else to run the event
529loop and will only block when necessary (usually when told by the user). 558loop and will only block when necessary (usually when told by the user).
530 559
531The instrument to do that is called a "condition variable", so called 560The tool to do that is called a "condition variable", so called because
532because they represent a condition that must become true. 561they represent a condition that must become true.
533 562
534Now is probably a good time to look at the examples further below. 563Now is probably a good time to look at the examples further below.
535 564
536Condition variables can be created by calling the C<< AnyEvent->condvar 565Condition variables can be created by calling the C<< AnyEvent->condvar
537>> method, usually without arguments. The only argument pair allowed is 566>> method, usually without arguments. The only argument pair allowed is
542After creation, the condition variable is "false" until it becomes "true" 571After creation, the condition variable is "false" until it becomes "true"
543by calling the C<send> method (or calling the condition variable as if it 572by calling the C<send> method (or calling the condition variable as if it
544were a callback, read about the caveats in the description for the C<< 573were a callback, read about the caveats in the description for the C<<
545->send >> method). 574->send >> method).
546 575
547Condition variables are similar to callbacks, except that you can 576Since condition variables are the most complex part of the AnyEvent API, here are
548optionally wait for them. They can also be called merge points - points 577some different mental models of what they are - pick the ones you can connect to:
549in time where multiple outstanding events have been processed. And yet 578
550another way to call them is transactions - each condition variable can be 579=over 4
551used to represent a transaction, which finishes at some point and delivers 580
552a result. And yet some people know them as "futures" - a promise to 581=item * Condition variables are like callbacks - you can call them (and pass them instead
553compute/deliver something that you can wait for. 582of callbacks). Unlike callbacks however, you can also wait for them to be called.
583
584=item * Condition variables are signals - one side can emit or send them,
585the other side can wait for them, or install a handler that is called when
586the signal fires.
587
588=item * Condition variables are like "Merge Points" - points in your program
589where you merge multiple independent results/control flows into one.
590
591=item * Condition variables represent a transaction - functions that start
592some kind of transaction can return them, leaving the caller the choice
593between waiting in a blocking fashion, or setting a callback.
594
595=item * Condition variables represent future values, or promises to deliver
596some result, long before the result is available.
597
598=back
554 599
555Condition variables are very useful to signal that something has finished, 600Condition variables are very useful to signal that something has finished,
556for example, if you write a module that does asynchronous http requests, 601for example, if you write a module that does asynchronous http requests,
557then a condition variable would be the ideal candidate to signal the 602then a condition variable would be the ideal candidate to signal the
558availability of results. The user can either act when the callback is 603availability of results. The user can either act when the callback is
571 616
572Condition variables are represented by hash refs in perl, and the keys 617Condition variables are represented by hash refs in perl, and the keys
573used by AnyEvent itself are all named C<_ae_XXX> to make subclassing 618used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
574easy (it is often useful to build your own transaction class on top of 619easy (it is often useful to build your own transaction class on top of
575AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call 620AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
576it's C<new> method in your own C<new> method. 621its C<new> method in your own C<new> method.
577 622
578There are two "sides" to a condition variable - the "producer side" which 623There are two "sides" to a condition variable - the "producer side" which
579eventually calls C<< -> send >>, and the "consumer side", which waits 624eventually calls C<< -> send >>, and the "consumer side", which waits
580for the send to occur. 625for the send to occur.
581 626
582Example: wait for a timer. 627Example: wait for a timer.
583 628
584 # wait till the result is ready 629 # condition: "wait till the timer is fired"
585 my $result_ready = AnyEvent->condvar; 630 my $timer_fired = AnyEvent->condvar;
586 631
587 # do something such as adding a timer 632 # create the timer - we could wait for, say
588 # or socket watcher the calls $result_ready->send 633 # a handle becomign ready, or even an
589 # when the "result" is ready. 634 # AnyEvent::HTTP request to finish, but
590 # in this case, we simply use a timer: 635 # in this case, we simply use a timer:
591 my $w = AnyEvent->timer ( 636 my $w = AnyEvent->timer (
592 after => 1, 637 after => 1,
593 cb => sub { $result_ready->send }, 638 cb => sub { $timer_fired->send },
594 ); 639 );
595 640
596 # this "blocks" (while handling events) till the callback 641 # this "blocks" (while handling events) till the callback
597 # calls -<send 642 # calls ->send
598 $result_ready->recv; 643 $timer_fired->recv;
599 644
600Example: wait for a timer, but take advantage of the fact that condition 645Example: wait for a timer, but take advantage of the fact that condition
601variables are also callable directly. 646variables are also callable directly.
602 647
603 my $done = AnyEvent->condvar; 648 my $done = AnyEvent->condvar;
646they were a code reference). Calling them directly is the same as calling 691they were a code reference). Calling them directly is the same as calling
647C<send>. 692C<send>.
648 693
649=item $cv->croak ($error) 694=item $cv->croak ($error)
650 695
651Similar to send, but causes all call's to C<< ->recv >> to invoke 696Similar to send, but causes all calls to C<< ->recv >> to invoke
652C<Carp::croak> with the given error message/object/scalar. 697C<Carp::croak> with the given error message/object/scalar.
653 698
654This can be used to signal any errors to the condition variable 699This can be used to signal any errors to the condition variable
655user/consumer. Doing it this way instead of calling C<croak> directly 700user/consumer. Doing it this way instead of calling C<croak> directly
656delays the error detetcion, but has the overwhelmign advantage that it 701delays the error detection, but has the overwhelming advantage that it
657diagnoses the error at the place where the result is expected, and not 702diagnoses the error at the place where the result is expected, and not
658deep in some event clalback without connection to the actual code causing 703deep in some event callback with no connection to the actual code causing
659the problem. 704the problem.
660 705
661=item $cv->begin ([group callback]) 706=item $cv->begin ([group callback])
662 707
663=item $cv->end 708=item $cv->end
701one call to C<begin>, so the condvar waits for all calls to C<end> before 746one call to C<begin>, so the condvar waits for all calls to C<end> before
702sending. 747sending.
703 748
704The ping example mentioned above is slightly more complicated, as the 749The ping example mentioned above is slightly more complicated, as the
705there are results to be passwd back, and the number of tasks that are 750there are results to be passwd back, and the number of tasks that are
706begung can potentially be zero: 751begun can potentially be zero:
707 752
708 my $cv = AnyEvent->condvar; 753 my $cv = AnyEvent->condvar;
709 754
710 my %result; 755 my %result;
711 $cv->begin (sub { shift->send (\%result) }); 756 $cv->begin (sub { shift->send (\%result) });
718 }; 763 };
719 } 764 }
720 765
721 $cv->end; 766 $cv->end;
722 767
768 ...
769
770 my $results = $cv->recv;
771
723This code fragment supposedly pings a number of hosts and calls 772This code fragment supposedly pings a number of hosts and calls
724C<send> after results for all then have have been gathered - in any 773C<send> after results for all then have have been gathered - in any
725order. To achieve this, the code issues a call to C<begin> when it starts 774order. To achieve this, the code issues a call to C<begin> when it starts
726each ping request and calls C<end> when it has received some result for 775each ping request and calls C<end> when it has received some result for
727it. Since C<begin> and C<end> only maintain a counter, the order in which 776it. Since C<begin> and C<end> only maintain a counter, the order in which
732to be called once the counter reaches C<0>, and second, it ensures that 781to be called once the counter reaches C<0>, and second, it ensures that
733C<send> is called even when C<no> hosts are being pinged (the loop 782C<send> is called even when C<no> hosts are being pinged (the loop
734doesn't execute once). 783doesn't execute once).
735 784
736This is the general pattern when you "fan out" into multiple (but 785This is the general pattern when you "fan out" into multiple (but
737potentially none) subrequests: use an outer C<begin>/C<end> pair to set 786potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
738the callback and ensure C<end> is called at least once, and then, for each 787the callback and ensure C<end> is called at least once, and then, for each
739subrequest you start, call C<begin> and for each subrequest you finish, 788subrequest you start, call C<begin> and for each subrequest you finish,
740call C<end>. 789call C<end>.
741 790
742=back 791=back
749=over 4 798=over 4
750 799
751=item $cv->recv 800=item $cv->recv
752 801
753Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 802Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
754>> methods have been called on c<$cv>, while servicing other watchers 803>> methods have been called on C<$cv>, while servicing other watchers
755normally. 804normally.
756 805
757You can only wait once on a condition - additional calls are valid but 806You can only wait once on a condition - additional calls are valid but
758will return immediately. 807will return immediately.
759 808
776caller decide whether the call will block or not (for example, by coupling 825caller decide whether the call will block or not (for example, by coupling
777condition variables with some kind of request results and supporting 826condition variables with some kind of request results and supporting
778callbacks so the caller knows that getting the result will not block, 827callbacks so the caller knows that getting the result will not block,
779while still supporting blocking waits if the caller so desires). 828while still supporting blocking waits if the caller so desires).
780 829
781You can ensure that C<< -recv >> never blocks by setting a callback and 830You can ensure that C<< ->recv >> never blocks by setting a callback and
782only calling C<< ->recv >> from within that callback (or at a later 831only calling C<< ->recv >> from within that callback (or at a later
783time). This will work even when the event loop does not support blocking 832time). This will work even when the event loop does not support blocking
784waits otherwise. 833waits otherwise.
785 834
786=item $bool = $cv->ready 835=item $bool = $cv->ready
791=item $cb = $cv->cb ($cb->($cv)) 840=item $cb = $cv->cb ($cb->($cv))
792 841
793This is a mutator function that returns the callback set and optionally 842This is a mutator function that returns the callback set and optionally
794replaces it before doing so. 843replaces it before doing so.
795 844
796The callback will be called when the condition becomes (or already was) 845The callback will be called when the condition becomes "true", i.e. when
797"true", i.e. when C<send> or C<croak> are called (or were called), with 846C<send> or C<croak> are called, with the only argument being the
798the only argument being the condition variable itself. Calling C<recv> 847condition variable itself. If the condition is already true, the
848callback is called immediately when it is set. Calling C<recv> inside
799inside the callback or at any later time is guaranteed not to block. 849the callback or at any later time is guaranteed not to block.
800 850
801=back 851=back
802 852
803=head1 SUPPORTED EVENT LOOPS/BACKENDS 853=head1 SUPPORTED EVENT LOOPS/BACKENDS
804 854
812use. If EV is not installed, then AnyEvent will fall back to its own 862use. If EV is not installed, then AnyEvent will fall back to its own
813pure-perl implementation, which is available everywhere as it comes with 863pure-perl implementation, which is available everywhere as it comes with
814AnyEvent itself. 864AnyEvent itself.
815 865
816 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 866 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
817 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 867 AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
818 868
819=item Backends that are transparently being picked up when they are used. 869=item Backends that are transparently being picked up when they are used.
820 870
821These will be used when they are currently loaded when the first watcher 871These will be used if they are already loaded when the first watcher
822is created, in which case it is assumed that the application is using 872is created, in which case it is assumed that the application is using
823them. This means that AnyEvent will automatically pick the right backend 873them. This means that AnyEvent will automatically pick the right backend
824when the main program loads an event module before anything starts to 874when the main program loads an event module before anything starts to
825create watchers. Nothing special needs to be done by the main program. 875create watchers. Nothing special needs to be done by the main program.
826 876
828 AnyEvent::Impl::Glib based on Glib, slow but very stable. 878 AnyEvent::Impl::Glib based on Glib, slow but very stable.
829 AnyEvent::Impl::Tk based on Tk, very broken. 879 AnyEvent::Impl::Tk based on Tk, very broken.
830 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 880 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
831 AnyEvent::Impl::POE based on POE, very slow, some limitations. 881 AnyEvent::Impl::POE based on POE, very slow, some limitations.
832 AnyEvent::Impl::Irssi used when running within irssi. 882 AnyEvent::Impl::Irssi used when running within irssi.
883 AnyEvent::Impl::IOAsync based on IO::Async.
884 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
885 AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
833 886
834=item Backends with special needs. 887=item Backends with special needs.
835 888
836Qt requires the Qt::Application to be instantiated first, but will 889Qt requires the Qt::Application to be instantiated first, but will
837otherwise be picked up automatically. As long as the main program 890otherwise be picked up automatically. As long as the main program
838instantiates the application before any AnyEvent watchers are created, 891instantiates the application before any AnyEvent watchers are created,
839everything should just work. 892everything should just work.
840 893
841 AnyEvent::Impl::Qt based on Qt. 894 AnyEvent::Impl::Qt based on Qt.
842 895
843Support for IO::Async can only be partial, as it is too broken and
844architecturally limited to even support the AnyEvent API. It also
845is the only event loop that needs the loop to be set explicitly, so
846it can only be used by a main program knowing about AnyEvent. See
847L<AnyEvent::Impl::Async> for the gory details.
848
849 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
850
851=item Event loops that are indirectly supported via other backends. 896=item Event loops that are indirectly supported via other backends.
852 897
853Some event loops can be supported via other modules: 898Some event loops can be supported via other modules:
854 899
855There is no direct support for WxWidgets (L<Wx>) or L<Prima>. 900There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
880Contains C<undef> until the first watcher is being created, before the 925Contains C<undef> until the first watcher is being created, before the
881backend has been autodetected. 926backend has been autodetected.
882 927
883Afterwards it contains the event model that is being used, which is the 928Afterwards it contains the event model that is being used, which is the
884name of the Perl class implementing the model. This class is usually one 929name of the Perl class implementing the model. This class is usually one
885of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the 930of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
886case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it 931case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
887will be C<urxvt::anyevent>). 932will be C<urxvt::anyevent>).
888 933
889=item AnyEvent::detect 934=item AnyEvent::detect
890 935
891Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 936Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
892if necessary. You should only call this function right before you would 937if necessary. You should only call this function right before you would
893have created an AnyEvent watcher anyway, that is, as late as possible at 938have created an AnyEvent watcher anyway, that is, as late as possible at
894runtime, and not e.g. while initialising of your module. 939runtime, and not e.g. during initialisation of your module.
940
941The effect of calling this function is as if a watcher had been created
942(specifically, actions that happen "when the first watcher is created"
943happen when calling detetc as well).
895 944
896If you need to do some initialisation before AnyEvent watchers are 945If you need to do some initialisation before AnyEvent watchers are
897created, use C<post_detect>. 946created, use C<post_detect>.
898 947
899=item $guard = AnyEvent::post_detect { BLOCK } 948=item $guard = AnyEvent::post_detect { BLOCK }
900 949
901Arranges for the code block to be executed as soon as the event model is 950Arranges for the code block to be executed as soon as the event model is
902autodetected (or immediately if this has already happened). 951autodetected (or immediately if that has already happened).
903 952
904The block will be executed I<after> the actual backend has been detected 953The block will be executed I<after> the actual backend has been detected
905(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been 954(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
906created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do 955created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
907other initialisations - see the sources of L<AnyEvent::Strict> or 956other initialisations - see the sources of L<AnyEvent::Strict> or
916that automatically removes the callback again when it is destroyed (or 965that automatically removes the callback again when it is destroyed (or
917C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for 966C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
918a case where this is useful. 967a case where this is useful.
919 968
920Example: Create a watcher for the IO::AIO module and store it in 969Example: Create a watcher for the IO::AIO module and store it in
921C<$WATCHER>. Only do so after the event loop is initialised, though. 970C<$WATCHER>, but do so only do so after the event loop is initialised.
922 971
923 our WATCHER; 972 our WATCHER;
924 973
925 my $guard = AnyEvent::post_detect { 974 my $guard = AnyEvent::post_detect {
926 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); 975 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
934 $WATCHER ||= $guard; 983 $WATCHER ||= $guard;
935 984
936=item @AnyEvent::post_detect 985=item @AnyEvent::post_detect
937 986
938If there are any code references in this array (you can C<push> to it 987If there are any code references in this array (you can C<push> to it
939before or after loading AnyEvent), then they will called directly after 988before or after loading AnyEvent), then they will be called directly
940the event loop has been chosen. 989after the event loop has been chosen.
941 990
942You should check C<$AnyEvent::MODEL> before adding to this array, though: 991You should check C<$AnyEvent::MODEL> before adding to this array, though:
943if it is defined then the event loop has already been detected, and the 992if it is defined then the event loop has already been detected, and the
944array will be ignored. 993array will be ignored.
945 994
946Best use C<AnyEvent::post_detect { BLOCK }> when your application allows 995Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
947it,as it takes care of these details. 996it, as it takes care of these details.
948 997
949This variable is mainly useful for modules that can do something useful 998This variable is mainly useful for modules that can do something useful
950when AnyEvent is used and thus want to know when it is initialised, but do 999when AnyEvent is used and thus want to know when it is initialised, but do
951not need to even load it by default. This array provides the means to hook 1000not need to even load it by default. This array provides the means to hook
952into AnyEvent passively, without loading it. 1001into AnyEvent passively, without loading it.
953 1002
1003Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
1004together, you could put this into Coro (this is the actual code used by
1005Coro to accomplish this):
1006
1007 if (defined $AnyEvent::MODEL) {
1008 # AnyEvent already initialised, so load Coro::AnyEvent
1009 require Coro::AnyEvent;
1010 } else {
1011 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
1012 # as soon as it is
1013 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
1014 }
1015
1016=item AnyEvent::postpone { BLOCK }
1017
1018Arranges for the block to be executed as soon as possible, but not before
1019the call itself returns. In practise, the block will be executed just
1020before the event loop polls for new events, or shortly afterwards.
1021
1022This function never returns anything (to make the C<return postpone { ...
1023}> idiom more useful.
1024
1025To understand the usefulness of this function, consider a function that
1026asynchronously does something for you and returns some transaction
1027object or guard to let you cancel the operation. For example,
1028C<AnyEvent::Socket::tcp_connect>:
1029
1030 # start a conenction attempt unless one is active
1031 $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
1032 delete $self->{connect_guard};
1033 ...
1034 };
1035
1036Imagine that this function could instantly call the callback, for
1037example, because it detects an obvious error such as a negative port
1038number. Invoking the callback before the function returns causes problems
1039however: the callback will be called and will try to delete the guard
1040object. But since the function hasn't returned yet, there is nothing to
1041delete. When the function eventually returns it will assign the guard
1042object to C<< $self->{connect_guard} >>, where it will likely never be
1043deleted, so the program thinks it is still trying to connect.
1044
1045This is where C<AnyEvent::postpone> should be used. Instead of calling the
1046callback directly on error:
1047
1048 $cb->(undef), return # signal error to callback, BAD!
1049 if $some_error_condition;
1050
1051It should use C<postpone>:
1052
1053 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1054 if $some_error_condition;
1055
1056=item AnyEvent::log $level, $msg[, @args]
1057
1058Log the given C<$msg> at the given C<$level>.
1059
1060If L<AnyEvent::Log> is not loaded then this function makes a simple test
1061to see whether the message will be logged. If the test succeeds it will
1062load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
1063the L<AnyEvent::Log> documentation for details.
1064
1065If the test fails it will simply return. Right now this happens when a
1066numerical loglevel is used and it is larger than the level specified via
1067C<$ENV{PERL_ANYEVENT_VERBOSE}>.
1068
1069If you want to sprinkle loads of logging calls around your code, consider
1070creating a logger callback with the C<AnyEvent::Log::logger> function,
1071which can reduce typing, codesize and can reduce the logging overhead
1072enourmously.
1073
954=back 1074=back
955 1075
956=head1 WHAT TO DO IN A MODULE 1076=head1 WHAT TO DO IN A MODULE
957 1077
958As a module author, you should C<use AnyEvent> and call AnyEvent methods 1078As a module author, you should C<use AnyEvent> and call AnyEvent methods
968because it will stall the whole program, and the whole point of using 1088because it will stall the whole program, and the whole point of using
969events is to stay interactive. 1089events is to stay interactive.
970 1090
971It is fine, however, to call C<< ->recv >> when the user of your module 1091It is fine, however, to call C<< ->recv >> when the user of your module
972requests it (i.e. if you create a http request object ad have a method 1092requests it (i.e. if you create a http request object ad have a method
973called C<results> that returns the results, it should call C<< ->recv >> 1093called C<results> that returns the results, it may call C<< ->recv >>
974freely, as the user of your module knows what she is doing. always). 1094freely, as the user of your module knows what she is doing. Always).
975 1095
976=head1 WHAT TO DO IN THE MAIN PROGRAM 1096=head1 WHAT TO DO IN THE MAIN PROGRAM
977 1097
978There will always be a single main program - the only place that should 1098There will always be a single main program - the only place that should
979dictate which event model to use. 1099dictate which event model to use.
980 1100
981If it doesn't care, it can just "use AnyEvent" and use it itself, or not 1101If the program is not event-based, it need not do anything special, even
982do anything special (it does not need to be event-based) and let AnyEvent 1102when it depends on a module that uses an AnyEvent. If the program itself
983decide which implementation to chose if some module relies on it. 1103uses AnyEvent, but does not care which event loop is used, all it needs
1104to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
1105available loop implementation.
984 1106
985If the main program relies on a specific event model - for example, in 1107If the main program relies on a specific event model - for example, in
986Gtk2 programs you have to rely on the Glib module - you should load the 1108Gtk2 programs you have to rely on the Glib module - you should load the
987event module before loading AnyEvent or any module that uses it: generally 1109event module before loading AnyEvent or any module that uses it: generally
988speaking, you should load it as early as possible. The reason is that 1110speaking, you should load it as early as possible. The reason is that
989modules might create watchers when they are loaded, and AnyEvent will 1111modules might create watchers when they are loaded, and AnyEvent will
990decide on the event model to use as soon as it creates watchers, and it 1112decide on the event model to use as soon as it creates watchers, and it
991might chose the wrong one unless you load the correct one yourself. 1113might choose the wrong one unless you load the correct one yourself.
992 1114
993You can chose to use a pure-perl implementation by loading the 1115You can chose to use a pure-perl implementation by loading the
994C<AnyEvent::Impl::Perl> module, which gives you similar behaviour 1116C<AnyEvent::Loop> module, which gives you similar behaviour
995everywhere, but letting AnyEvent chose the model is generally better. 1117everywhere, but letting AnyEvent chose the model is generally better.
996 1118
997=head2 MAINLOOP EMULATION 1119=head2 MAINLOOP EMULATION
998 1120
999Sometimes (often for short test scripts, or even standalone programs who 1121Sometimes (often for short test scripts, or even standalone programs who
1012 1134
1013 1135
1014=head1 OTHER MODULES 1136=head1 OTHER MODULES
1015 1137
1016The following is a non-exhaustive list of additional modules that use 1138The following is a non-exhaustive list of additional modules that use
1017AnyEvent as a client and can therefore be mixed easily with other AnyEvent 1139AnyEvent as a client and can therefore be mixed easily with other
1018modules and other event loops in the same program. Some of the modules 1140AnyEvent modules and other event loops in the same program. Some of the
1019come with AnyEvent, most are available via CPAN. 1141modules come as part of AnyEvent, the others are available via CPAN (see
1142L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
1143a longer non-exhaustive list), and the list is heavily biased towards
1144modules of the AnyEvent author himself :)
1020 1145
1021=over 4 1146=over 4
1022 1147
1023=item L<AnyEvent::Util> 1148=item L<AnyEvent::Util>
1024 1149
1025Contains various utility functions that replace often-used but blocking 1150Contains various utility functions that replace often-used blocking
1026functions such as C<inet_aton> by event-/callback-based versions. 1151functions such as C<inet_aton> with event/callback-based versions.
1027 1152
1028=item L<AnyEvent::Socket> 1153=item L<AnyEvent::Socket>
1029 1154
1030Provides various utility functions for (internet protocol) sockets, 1155Provides various utility functions for (internet protocol) sockets,
1031addresses and name resolution. Also functions to create non-blocking tcp 1156addresses and name resolution. Also functions to create non-blocking tcp
1033 1158
1034=item L<AnyEvent::Handle> 1159=item L<AnyEvent::Handle>
1035 1160
1036Provide read and write buffers, manages watchers for reads and writes, 1161Provide read and write buffers, manages watchers for reads and writes,
1037supports raw and formatted I/O, I/O queued and fully transparent and 1162supports raw and formatted I/O, I/O queued and fully transparent and
1038non-blocking SSL/TLS (via L<AnyEvent::TLS>. 1163non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1039 1164
1040=item L<AnyEvent::DNS> 1165=item L<AnyEvent::DNS>
1041 1166
1042Provides rich asynchronous DNS resolver capabilities. 1167Provides rich asynchronous DNS resolver capabilities.
1043 1168
1169=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
1170
1171Implement event-based interfaces to the protocols of the same name (for
1172the curious, IGS is the International Go Server and FCP is the Freenet
1173Client Protocol).
1174
1044=item L<AnyEvent::HTTP> 1175=item L<AnyEvent::AIO>
1045 1176
1046A simple-to-use HTTP library that is capable of making a lot of concurrent 1177Truly asynchronous (as opposed to non-blocking) I/O, should be in the
1047HTTP requests. 1178toolbox of every event programmer. AnyEvent::AIO transparently fuses
1179L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
1180file I/O, and much more.
1181
1182=item L<AnyEvent::Filesys::Notify>
1183
1184AnyEvent is good for non-blocking stuff, but it can't detect file or
1185path changes (e.g. "watch this directory for new files", "watch this
1186file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
1187do just that in a portbale fashion, supporting inotify on GNU/Linux and
1188some weird, without doubt broken, stuff on OS X to monitor files. It can
1189fall back to blocking scans at regular intervals transparently on other
1190platforms, so it's about as portable as it gets.
1191
1192(I haven't used it myself, but I haven't heard anybody complaining about
1193it yet).
1194
1195=item L<AnyEvent::DBI>
1196
1197Executes L<DBI> requests asynchronously in a proxy process for you,
1198notifying you in an event-based way when the operation is finished.
1048 1199
1049=item L<AnyEvent::HTTPD> 1200=item L<AnyEvent::HTTPD>
1050 1201
1051Provides a simple web application server framework. 1202A simple embedded webserver.
1052 1203
1053=item L<AnyEvent::FastPing> 1204=item L<AnyEvent::FastPing>
1054 1205
1055The fastest ping in the west. 1206The fastest ping in the west.
1056 1207
1057=item L<AnyEvent::DBI>
1058
1059Executes L<DBI> requests asynchronously in a proxy process.
1060
1061=item L<AnyEvent::AIO>
1062
1063Truly asynchronous I/O, should be in the toolbox of every event
1064programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1065together.
1066
1067=item L<AnyEvent::BDB>
1068
1069Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1070L<BDB> and AnyEvent together.
1071
1072=item L<AnyEvent::GPSD>
1073
1074A non-blocking interface to gpsd, a daemon delivering GPS information.
1075
1076=item L<AnyEvent::IRC>
1077
1078AnyEvent based IRC client module family (replacing the older Net::IRC3).
1079
1080=item L<AnyEvent::XMPP>
1081
1082AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1083Net::XMPP2>.
1084
1085=item L<AnyEvent::IGS>
1086
1087A non-blocking interface to the Internet Go Server protocol (used by
1088L<App::IGS>).
1089
1090=item L<Net::FCP>
1091
1092AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1093of AnyEvent.
1094
1095=item L<Event::ExecFlow>
1096
1097High level API for event-based execution flow control.
1098
1099=item L<Coro> 1208=item L<Coro>
1100 1209
1101Has special support for AnyEvent via L<Coro::AnyEvent>. 1210Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
1211to simply invert the flow control - don't call us, we will call you:
1212
1213 async {
1214 Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
1215 print "5 seconds later!\n";
1216
1217 Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
1218 my $line = <STDIN>; # works for ttys
1219
1220 AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
1221 my ($body, $hdr) = Coro::rouse_wait;
1222 };
1102 1223
1103=back 1224=back
1104 1225
1105=cut 1226=cut
1106 1227
1107package AnyEvent; 1228package AnyEvent;
1108 1229
1109# basically a tuned-down version of common::sense 1230# basically a tuned-down version of common::sense
1110sub common_sense { 1231sub common_sense {
1111 # no warnings 1232 # from common:.sense 3.5
1112 ${^WARNING_BITS} ^= ${^WARNING_BITS}; 1233 local $^W;
1113 # use strict vars subs 1234 ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1235 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1114 $^H |= 0x00000600; 1236 $^H |= 0x00000600;
1115} 1237}
1116 1238
1117BEGIN { AnyEvent::common_sense } 1239BEGIN { AnyEvent::common_sense }
1118 1240
1119use Carp (); 1241use Carp ();
1120 1242
1121our $VERSION = '5.0'; 1243our $VERSION = '7.04';
1122our $MODEL; 1244our $MODEL;
1123
1124our $AUTOLOAD;
1125our @ISA; 1245our @ISA;
1126
1127our @REGISTRY; 1246our @REGISTRY;
1128
1129our $WIN32;
1130
1131our $VERBOSE; 1247our $VERBOSE;
1248our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1249our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1132 1250
1133BEGIN { 1251BEGIN {
1134 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1252 require "AnyEvent/constants.pl";
1253
1135 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1254 eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1136 1255
1137 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1256 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1138 if ${^TAINT}; 1257 if ${^TAINT};
1139 1258
1140 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1259 $ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
1260 for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1141 1261
1142} 1262 @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
1263 if ${^TAINT};
1143 1264
1144our $MAX_SIGNAL_LATENCY = 10; 1265 # $ENV{PERL_ANYEVENT_xxx} now valid
1145 1266
1146our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1267 $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1147 1268
1148{
1149 my $idx; 1269 my $idx;
1150 $PROTOCOL{$_} = ++$idx 1270 $PROTOCOL{$_} = ++$idx
1151 for reverse split /\s*,\s*/, 1271 for reverse split /\s*,\s*/,
1152 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1272 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1153} 1273}
1154 1274
1275our @post_detect;
1276
1277sub post_detect(&) {
1278 my ($cb) = @_;
1279
1280 push @post_detect, $cb;
1281
1282 defined wantarray
1283 ? bless \$cb, "AnyEvent::Util::postdetect"
1284 : ()
1285}
1286
1287sub AnyEvent::Util::postdetect::DESTROY {
1288 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1289}
1290
1291our $POSTPONE_W;
1292our @POSTPONE;
1293
1294sub _postpone_exec {
1295 undef $POSTPONE_W;
1296
1297 &{ shift @POSTPONE }
1298 while @POSTPONE;
1299}
1300
1301sub postpone(&) {
1302 push @POSTPONE, shift;
1303
1304 $POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
1305
1306 ()
1307}
1308
1309sub log($$;@) {
1310 # only load the big bloated module when we actually are about to log something
1311 if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
1312 local ($!, $@);
1313 require AnyEvent::Log; # among other things, sets $VERBOSE to 9
1314 # AnyEvent::Log overwrites this function
1315 goto &log;
1316 }
1317
1318 0 # not logged
1319}
1320
1321sub _logger($;$) {
1322 my ($level, $renabled) = @_;
1323
1324 $$renabled = $level <= $VERBOSE;
1325
1326 my $logger = [(caller)[0], $level, $renabled];
1327
1328 $AnyEvent::Log::LOGGER{$logger+0} = $logger;
1329
1330# return unless defined wantarray;
1331#
1332# require AnyEvent::Util;
1333# my $guard = AnyEvent::Util::guard (sub {
1334# # "clean up"
1335# delete $LOGGER{$logger+0};
1336# });
1337#
1338# sub {
1339# return 0 unless $$renabled;
1340#
1341# $guard if 0; # keep guard alive, but don't cause runtime overhead
1342# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
1343# package AnyEvent::Log;
1344# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
1345# }
1346}
1347
1348if (length $ENV{PERL_ANYEVENT_LOG}) {
1349 require AnyEvent::Log; # AnyEvent::Log does the thing for us
1350}
1351
1155my @models = ( 1352our @models = (
1156 [EV:: => AnyEvent::Impl::EV:: , 1], 1353 [EV:: => AnyEvent::Impl::EV::],
1157 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], 1354 [AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1158 # everything below here will not (normally) be autoprobed 1355 # everything below here will not (normally) be autoprobed
1159 # as the pureperl backend should work everywhere 1356 # as the pure perl backend should work everywhere
1160 # and is usually faster 1357 # and is usually faster
1358 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
1161 [Event:: => AnyEvent::Impl::Event::, 1], 1359 [Event:: => AnyEvent::Impl::Event::], # slow, stable
1162 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers 1360 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1361 # everything below here should not be autoloaded
1163 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1362 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1164 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1165 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1363 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1166 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1364 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1167 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1365 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1168 [Wx:: => AnyEvent::Impl::POE::], 1366 [Wx:: => AnyEvent::Impl::POE::],
1169 [Prima:: => AnyEvent::Impl::POE::], 1367 [Prima:: => AnyEvent::Impl::POE::],
1170 # IO::Async is just too broken - we would need workarounds for its 1368 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1171 # byzantine signal and broken child handling, among others. 1369 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1172 # IO::Async is rather hard to detect, as it doesn't have any 1370 [FLTK:: => AnyEvent::Impl::FLTK::],
1173 # obvious default class.
1174 [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1175 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1176 [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1177 [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1178); 1371);
1179 1372
1180our %method = map +($_ => 1), 1373our @isa_hook;
1374
1375sub _isa_set {
1376 my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
1377
1378 @{"$pkg[$_-1]::ISA"} = $pkg[$_]
1379 for 1 .. $#pkg;
1380
1381 grep $_ && $_->[1], @isa_hook
1382 and AE::_reset ();
1383}
1384
1385# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
1386sub _isa_hook($$;$) {
1387 my ($i, $pkg, $reset_ae) = @_;
1388
1389 $isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
1390
1391 _isa_set;
1392}
1393
1394# all autoloaded methods reserve the complete glob, not just the method slot.
1395# due to bugs in perls method cache implementation.
1181 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1396our @methods = qw(io timer time now now_update signal child idle condvar);
1182 1397
1183our @post_detect;
1184
1185sub post_detect(&) { 1398sub detect() {
1186 my ($cb) = @_; 1399 return $MODEL if $MODEL; # some programs keep references to detect
1187 1400
1188 if ($MODEL) { 1401 # IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1189 $cb->(); 1402 # the author knows about the problems and what it does to AnyEvent as a whole
1403 # (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
1404 # anyway.
1405 AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
1406 . "design, abuses internals and breaks AnyEvent - will not continue."
1407 if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1190 1408
1191 undef 1409 local $!; # for good measure
1410 local $SIG{__DIE__}; # we use eval
1411
1412 # free some memory
1413 *detect = sub () { $MODEL };
1414 # undef &func doesn't correctly update the method cache. grmbl.
1415 # so we delete the whole glob. grmbl.
1416 # otoh, perl doesn't let me undef an active usb, but it lets me free
1417 # a glob with an active sub. hrm. i hope it works, but perl is
1418 # usually buggy in this department. sigh.
1419 delete @{"AnyEvent::"}{@methods};
1420 undef @methods;
1421
1422 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
1423 my $model = $1;
1424 $model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
1425 if (eval "require $model") {
1426 AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
1427 $MODEL = $model;
1192 } else { 1428 } else {
1193 push @post_detect, $cb; 1429 AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1194 1430 }
1195 defined wantarray
1196 ? bless \$cb, "AnyEvent::Util::postdetect"
1197 : ()
1198 } 1431 }
1199}
1200 1432
1201sub AnyEvent::Util::postdetect::DESTROY { 1433 # check for already loaded models
1202 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1203}
1204
1205sub detect() {
1206 unless ($MODEL) { 1434 unless ($MODEL) {
1207 local $SIG{__DIE__}; 1435 for (@REGISTRY, @models) {
1208 1436 my ($package, $model) = @$_;
1209 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1437 if (${"$package\::VERSION"} > 0) {
1210 my $model = "AnyEvent::Impl::$1";
1211 if (eval "require $model") { 1438 if (eval "require $model") {
1439 AnyEvent::log 7 => "Autodetected model '$model', using it.";
1212 $MODEL = $model; 1440 $MODEL = $model;
1213 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; 1441 last;
1214 } else { 1442 } else {
1215 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; 1443 AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
1444 }
1216 } 1445 }
1217 } 1446 }
1218 1447
1219 # check for already loaded models
1220 unless ($MODEL) { 1448 unless ($MODEL) {
1449 # try to autoload a model
1221 for (@REGISTRY, @models) { 1450 for (@REGISTRY, @models) {
1222 my ($package, $model) = @$_; 1451 my ($package, $model) = @$_;
1452 if (
1453 eval "require $package"
1223 if (${"$package\::VERSION"} > 0) { 1454 and ${"$package\::VERSION"} > 0
1224 if (eval "require $model") { 1455 and eval "require $model"
1456 ) {
1457 AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1225 $MODEL = $model; 1458 $MODEL = $model;
1226 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1227 last; 1459 last;
1228 }
1229 } 1460 }
1230 } 1461 }
1231 1462
1232 unless ($MODEL) {
1233 # try to autoload a model
1234 for (@REGISTRY, @models) {
1235 my ($package, $model, $autoload) = @$_;
1236 if (
1237 $autoload
1238 and eval "require $package"
1239 and ${"$package\::VERSION"} > 0
1240 and eval "require $model"
1241 ) {
1242 $MODEL = $model;
1243 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1244 last;
1245 }
1246 }
1247
1248 $MODEL 1463 $MODEL
1249 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; 1464 or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1250 }
1251 } 1465 }
1252
1253 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1254
1255 unshift @ISA, $MODEL;
1256
1257 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1258
1259 (shift @post_detect)->() while @post_detect;
1260 } 1466 }
1261 1467
1468 # free memory only needed for probing
1469 undef @models;
1470 undef @REGISTRY;
1471
1472 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1473
1474 # now nuke some methods that are overridden by the backend.
1475 # SUPER usage is not allowed in these.
1476 for (qw(time signal child idle)) {
1477 undef &{"AnyEvent::Base::$_"}
1478 if defined &{"$MODEL\::$_"};
1479 }
1480
1481 _isa_set;
1482
1483 # we're officially open!
1484
1485 if ($ENV{PERL_ANYEVENT_STRICT}) {
1486 require AnyEvent::Strict;
1487 }
1488
1489 if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
1490 require AnyEvent::Debug;
1491 AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
1492 }
1493
1494 if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
1495 require AnyEvent::Socket;
1496 require AnyEvent::Debug;
1497
1498 my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
1499 $shell =~ s/\$\$/$$/g;
1500
1501 my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
1502 $AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
1503 }
1504
1505 # now the anyevent environment is set up as the user told us to, so
1506 # call the actual user code - post detects
1507
1508 (shift @post_detect)->() while @post_detect;
1509 undef @post_detect;
1510
1511 *post_detect = sub(&) {
1512 shift->();
1513
1514 undef
1515 };
1516
1262 $MODEL 1517 $MODEL
1263} 1518}
1264 1519
1265sub AUTOLOAD { 1520for my $name (@methods) {
1266 (my $func = $AUTOLOAD) =~ s/.*://; 1521 *$name = sub {
1267 1522 detect;
1268 $method{$func} 1523 # we use goto because
1269 or Carp::croak "$func: not a valid method for AnyEvent objects"; 1524 # a) it makes the thunk more transparent
1270 1525 # b) it allows us to delete the thunk later
1271 detect unless $MODEL; 1526 goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1272 1527 };
1273 my $class = shift;
1274 $class->$func (@_);
1275} 1528}
1276 1529
1277# utility function to dup a filehandle. this is used by many backends 1530# utility function to dup a filehandle. this is used by many backends
1278# to support binding more than one watcher per filehandle (they usually 1531# to support binding more than one watcher per filehandle (they usually
1279# allow only one watcher per fd, so we dup it to get a different one). 1532# allow only one watcher per fd, so we dup it to get a different one).
1293 1546
1294=head1 SIMPLIFIED AE API 1547=head1 SIMPLIFIED AE API
1295 1548
1296Starting with version 5.0, AnyEvent officially supports a second, much 1549Starting with version 5.0, AnyEvent officially supports a second, much
1297simpler, API that is designed to reduce the calling, typing and memory 1550simpler, API that is designed to reduce the calling, typing and memory
1298overhead. 1551overhead by using function call syntax and a fixed number of parameters.
1299 1552
1300See the L<AE> manpage for details. 1553See the L<AE> manpage for details.
1301 1554
1302=cut 1555=cut
1303 1556
1304package AE; 1557package AE;
1305 1558
1306our $VERSION = $AnyEvent::VERSION; 1559our $VERSION = $AnyEvent::VERSION;
1307 1560
1561sub _reset() {
1562 eval q{
1563 # fall back to the main API by default - backends and AnyEvent::Base
1564 # implementations can overwrite these.
1565
1308sub io($$$) { 1566 sub io($$$) {
1309 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) 1567 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1310} 1568 }
1311 1569
1312sub timer($$$) { 1570 sub timer($$$) {
1313 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]) 1571 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1314} 1572 }
1315 1573
1316sub signal($$) { 1574 sub signal($$) {
1317 AnyEvent->signal (signal => $_[0], cb => $_[1]) 1575 AnyEvent->signal (signal => $_[0], cb => $_[1])
1318} 1576 }
1319 1577
1320sub child($$) { 1578 sub child($$) {
1321 AnyEvent->child (pid => $_[0], cb => $_[1]) 1579 AnyEvent->child (pid => $_[0], cb => $_[1])
1322} 1580 }
1323 1581
1324sub idle($) { 1582 sub idle($) {
1325 AnyEvent->idle (cb => $_[0]) 1583 AnyEvent->idle (cb => $_[0]);
1326} 1584 }
1327 1585
1328sub cv(;&) { 1586 sub cv(;&) {
1329 AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) 1587 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1330} 1588 }
1331 1589
1332sub now() { 1590 sub now() {
1333 AnyEvent->now 1591 AnyEvent->now
1334} 1592 }
1335 1593
1336sub now_update() { 1594 sub now_update() {
1337 AnyEvent->now_update 1595 AnyEvent->now_update
1338} 1596 }
1339 1597
1340sub time() { 1598 sub time() {
1341 AnyEvent->time 1599 AnyEvent->time
1600 }
1601
1602 *postpone = \&AnyEvent::postpone;
1603 *log = \&AnyEvent::log;
1604 };
1605 die if $@;
1342} 1606}
1607
1608BEGIN { _reset }
1343 1609
1344package AnyEvent::Base; 1610package AnyEvent::Base;
1345 1611
1346# default implementations for many methods 1612# default implementations for many methods
1347 1613
1348sub _time { 1614sub time {
1615 eval q{ # poor man's autoloading {}
1349 # probe for availability of Time::HiRes 1616 # probe for availability of Time::HiRes
1350 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1617 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1351 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1618 *time = sub { Time::HiRes::time () };
1352 *_time = \&Time::HiRes::time; 1619 *AE::time = \& Time::HiRes::time ;
1620 *now = \&time;
1621 AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1353 # if (eval "use POSIX (); (POSIX::times())... 1622 # if (eval "use POSIX (); (POSIX::times())...
1354 } else { 1623 } else {
1355 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; 1624 *time = sub { CORE::time };
1356 *_time = sub { time }; # epic fail 1625 *AE::time = sub (){ CORE::time };
1626 *now = \&time;
1627 AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
1628 }
1357 } 1629 };
1630 die if $@;
1358 1631
1359 &_time 1632 &time
1360} 1633}
1361 1634
1362sub time { _time } 1635*now = \&time;
1363sub now { _time }
1364sub now_update { } 1636sub now_update { }
1365 1637
1638sub _poll {
1639 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
1640}
1641
1366# default implementation for ->condvar 1642# default implementation for ->condvar
1643# in fact, the default should not be overwritten
1367 1644
1368sub condvar { 1645sub condvar {
1646 eval q{ # poor man's autoloading {}
1647 *condvar = sub {
1369 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1648 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1649 };
1650
1651 *AE::cv = sub (;&) {
1652 bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
1653 };
1654 };
1655 die if $@;
1656
1657 &condvar
1370} 1658}
1371 1659
1372# default implementation for ->signal 1660# default implementation for ->signal
1373 1661
1374our $HAVE_ASYNC_INTERRUPT; 1662our $HAVE_ASYNC_INTERRUPT;
1375 1663
1376sub _have_async_interrupt() { 1664sub _have_async_interrupt() {
1377 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} 1665 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1378 && eval "use Async::Interrupt 1.0 (); 1") 1666 && eval "use Async::Interrupt 1.02 (); 1")
1379 unless defined $HAVE_ASYNC_INTERRUPT; 1667 unless defined $HAVE_ASYNC_INTERRUPT;
1380 1668
1381 $HAVE_ASYNC_INTERRUPT 1669 $HAVE_ASYNC_INTERRUPT
1382} 1670}
1383 1671
1384our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1672our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1385our (%SIG_ASY, %SIG_ASY_W); 1673our (%SIG_ASY, %SIG_ASY_W);
1386our ($SIG_COUNT, $SIG_TW); 1674our ($SIG_COUNT, $SIG_TW);
1387 1675
1388sub _signal_exec {
1389 $HAVE_ASYNC_INTERRUPT
1390 ? $SIGPIPE_R->drain
1391 : sysread $SIGPIPE_R, my $dummy, 9;
1392
1393 while (%SIG_EV) {
1394 for (keys %SIG_EV) {
1395 delete $SIG_EV{$_};
1396 $_->() for values %{ $SIG_CB{$_} || {} };
1397 }
1398 }
1399}
1400
1401# install a dummy wakeup watcher to reduce signal catching latency 1676# install a dummy wakeup watcher to reduce signal catching latency
1677# used by Impls
1402sub _sig_add() { 1678sub _sig_add() {
1403 unless ($SIG_COUNT++) { 1679 unless ($SIG_COUNT++) {
1404 # try to align timer on a full-second boundary, if possible 1680 # try to align timer on a full-second boundary, if possible
1405 my $NOW = AE::now; 1681 my $NOW = AE::now;
1406 1682
1416 undef $SIG_TW 1692 undef $SIG_TW
1417 unless --$SIG_COUNT; 1693 unless --$SIG_COUNT;
1418} 1694}
1419 1695
1420our $_sig_name_init; $_sig_name_init = sub { 1696our $_sig_name_init; $_sig_name_init = sub {
1421 eval q{ # poor man's autoloading 1697 eval q{ # poor man's autoloading {}
1422 undef $_sig_name_init; 1698 undef $_sig_name_init;
1423 1699
1424 if (_have_async_interrupt) { 1700 if (_have_async_interrupt) {
1425 *sig2num = \&Async::Interrupt::sig2num; 1701 *sig2num = \&Async::Interrupt::sig2num;
1426 *sig2name = \&Async::Interrupt::sig2name; 1702 *sig2name = \&Async::Interrupt::sig2name;
1450 1726
1451sub signal { 1727sub signal {
1452 eval q{ # poor man's autoloading {} 1728 eval q{ # poor man's autoloading {}
1453 # probe for availability of Async::Interrupt 1729 # probe for availability of Async::Interrupt
1454 if (_have_async_interrupt) { 1730 if (_have_async_interrupt) {
1455 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8; 1731 AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1456 1732
1457 $SIGPIPE_R = new Async::Interrupt::EventPipe; 1733 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1458 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec; 1734 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1459 1735
1460 } else { 1736 } else {
1461 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8; 1737 AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1462
1463 require Fcntl;
1464 1738
1465 if (AnyEvent::WIN32) { 1739 if (AnyEvent::WIN32) {
1466 require AnyEvent::Util; 1740 require AnyEvent::Util;
1467 1741
1468 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); 1742 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1469 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R; 1743 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1470 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case 1744 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1471 } else { 1745 } else {
1472 pipe $SIGPIPE_R, $SIGPIPE_W; 1746 pipe $SIGPIPE_R, $SIGPIPE_W;
1473 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1747 fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1474 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case 1748 fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1475 1749
1476 # not strictly required, as $^F is normally 2, but let's make sure... 1750 # not strictly required, as $^F is normally 2, but let's make sure...
1477 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1751 fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1478 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1752 fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1479 } 1753 }
1480 1754
1481 $SIGPIPE_R 1755 $SIGPIPE_R
1482 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1756 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1483 1757
1484 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec; 1758 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1485 } 1759 }
1486 1760
1487 *signal = sub { 1761 *signal = $HAVE_ASYNC_INTERRUPT
1762 ? sub {
1488 my (undef, %arg) = @_; 1763 my (undef, %arg) = @_;
1489 1764
1490 my $signal = uc $arg{signal}
1491 or Carp::croak "required option 'signal' is missing";
1492
1493 if ($HAVE_ASYNC_INTERRUPT) {
1494 # async::interrupt 1765 # async::interrupt
1495
1496 $signal = sig2num $signal; 1766 my $signal = sig2num $arg{signal};
1497 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1767 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1498 1768
1499 $SIG_ASY{$signal} ||= new Async::Interrupt 1769 $SIG_ASY{$signal} ||= new Async::Interrupt
1500 cb => sub { undef $SIG_EV{$signal} }, 1770 cb => sub { undef $SIG_EV{$signal} },
1501 signal => $signal, 1771 signal => $signal,
1502 pipe => [$SIGPIPE_R->filenos], 1772 pipe => [$SIGPIPE_R->filenos],
1503 pipe_autodrain => 0, 1773 pipe_autodrain => 0,
1504 ; 1774 ;
1505 1775
1506 } else { 1776 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1777 }
1778 : sub {
1779 my (undef, %arg) = @_;
1780
1507 # pure perl 1781 # pure perl
1508
1509 # AE::Util has been loaded in signal
1510 $signal = sig2name $signal; 1782 my $signal = sig2name $arg{signal};
1511 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1783 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1512 1784
1513 $SIG{$signal} ||= sub { 1785 $SIG{$signal} ||= sub {
1514 local $!; 1786 local $!;
1515 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1787 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1516 undef $SIG_EV{$signal}; 1788 undef $SIG_EV{$signal};
1517 }; 1789 };
1518 1790
1519 # can't do signal processing without introducing races in pure perl, 1791 # can't do signal processing without introducing races in pure perl,
1520 # so limit the signal latency. 1792 # so limit the signal latency.
1521 _sig_add; 1793 _sig_add;
1522 }
1523 1794
1524 bless [$signal, $arg{cb}], "AnyEvent::Base::signal" 1795 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1796 }
1525 }; 1797 ;
1526 1798
1527 *AnyEvent::Base::signal::DESTROY = sub { 1799 *AnyEvent::Base::signal::DESTROY = sub {
1528 my ($signal, $cb) = @{$_[0]}; 1800 my ($signal, $cb) = @{$_[0]};
1529 1801
1530 _sig_del; 1802 _sig_del;
1537 # print weird messages, or just unconditionally exit 1809 # print weird messages, or just unconditionally exit
1538 # instead of getting the default action. 1810 # instead of getting the default action.
1539 undef $SIG{$signal} 1811 undef $SIG{$signal}
1540 unless keys %{ $SIG_CB{$signal} }; 1812 unless keys %{ $SIG_CB{$signal} };
1541 }; 1813 };
1814
1815 *_signal_exec = sub {
1816 $HAVE_ASYNC_INTERRUPT
1817 ? $SIGPIPE_R->drain
1818 : sysread $SIGPIPE_R, (my $dummy), 9;
1819
1820 while (%SIG_EV) {
1821 for (keys %SIG_EV) {
1822 delete $SIG_EV{$_};
1823 &$_ for values %{ $SIG_CB{$_} || {} };
1824 }
1825 }
1826 };
1542 }; 1827 };
1543 die if $@; 1828 die if $@;
1829
1544 &signal 1830 &signal
1545} 1831}
1546 1832
1547# default implementation for ->child 1833# default implementation for ->child
1548 1834
1549our %PID_CB; 1835our %PID_CB;
1550our $CHLD_W; 1836our $CHLD_W;
1551our $CHLD_DELAY_W; 1837our $CHLD_DELAY_W;
1552our $WNOHANG;
1553 1838
1839# used by many Impl's
1554sub _emit_childstatus($$) { 1840sub _emit_childstatus($$) {
1555 my (undef, $rpid, $rstatus) = @_; 1841 my (undef, $rpid, $rstatus) = @_;
1556 1842
1557 $_->($rpid, $rstatus) 1843 $_->($rpid, $rstatus)
1558 for values %{ $PID_CB{$rpid} || {} }, 1844 for values %{ $PID_CB{$rpid} || {} },
1559 values %{ $PID_CB{0} || {} }; 1845 values %{ $PID_CB{0} || {} };
1560} 1846}
1561 1847
1562sub _sigchld {
1563 my $pid;
1564
1565 AnyEvent->_emit_childstatus ($pid, $?)
1566 while ($pid = waitpid -1, $WNOHANG) > 0;
1567}
1568
1569sub child { 1848sub child {
1849 eval q{ # poor man's autoloading {}
1850 *_sigchld = sub {
1851 my $pid;
1852
1853 AnyEvent->_emit_childstatus ($pid, $?)
1854 while ($pid = waitpid -1, WNOHANG) > 0;
1855 };
1856
1857 *child = sub {
1570 my (undef, %arg) = @_; 1858 my (undef, %arg) = @_;
1571 1859
1572 defined (my $pid = $arg{pid} + 0) 1860 my $pid = $arg{pid};
1573 or Carp::croak "required option 'pid' is missing"; 1861 my $cb = $arg{cb};
1574 1862
1575 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1863 $PID_CB{$pid}{$cb+0} = $cb;
1576 1864
1577 # WNOHANG is almost cetrainly 1 everywhere
1578 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1579 ? 1
1580 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1581
1582 unless ($CHLD_W) { 1865 unless ($CHLD_W) {
1583 $CHLD_W = AE::signal CHLD => \&_sigchld; 1866 $CHLD_W = AE::signal CHLD => \&_sigchld;
1584 # child could be a zombie already, so make at least one round 1867 # child could be a zombie already, so make at least one round
1585 &_sigchld; 1868 &_sigchld;
1586 } 1869 }
1587 1870
1588 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1871 bless [$pid, $cb+0], "AnyEvent::Base::child"
1589} 1872 };
1590 1873
1591sub AnyEvent::Base::child::DESTROY { 1874 *AnyEvent::Base::child::DESTROY = sub {
1592 my ($pid, $cb) = @{$_[0]}; 1875 my ($pid, $icb) = @{$_[0]};
1593 1876
1594 delete $PID_CB{$pid}{$cb}; 1877 delete $PID_CB{$pid}{$icb};
1595 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1878 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1596 1879
1597 undef $CHLD_W unless keys %PID_CB; 1880 undef $CHLD_W unless keys %PID_CB;
1881 };
1882 };
1883 die if $@;
1884
1885 &child
1598} 1886}
1599 1887
1600# idle emulation is done by simply using a timer, regardless 1888# idle emulation is done by simply using a timer, regardless
1601# of whether the process is idle or not, and not letting 1889# of whether the process is idle or not, and not letting
1602# the callback use more than 50% of the time. 1890# the callback use more than 50% of the time.
1603sub idle { 1891sub idle {
1892 eval q{ # poor man's autoloading {}
1893 *idle = sub {
1604 my (undef, %arg) = @_; 1894 my (undef, %arg) = @_;
1605 1895
1606 my ($cb, $w, $rcb) = $arg{cb}; 1896 my ($cb, $w, $rcb) = $arg{cb};
1607 1897
1608 $rcb = sub { 1898 $rcb = sub {
1609 if ($cb) { 1899 if ($cb) {
1610 $w = _time; 1900 $w = AE::time;
1611 &$cb; 1901 &$cb;
1612 $w = _time - $w; 1902 $w = AE::time - $w;
1613 1903
1614 # never use more then 50% of the time for the idle watcher, 1904 # never use more then 50% of the time for the idle watcher,
1615 # within some limits 1905 # within some limits
1616 $w = 0.0001 if $w < 0.0001; 1906 $w = 0.0001 if $w < 0.0001;
1617 $w = 5 if $w > 5; 1907 $w = 5 if $w > 5;
1618 1908
1619 $w = AE::timer $w, 0, $rcb; 1909 $w = AE::timer $w, 0, $rcb;
1620 } else { 1910 } else {
1621 # clean up... 1911 # clean up...
1622 undef $w; 1912 undef $w;
1623 undef $rcb; 1913 undef $rcb;
1914 }
1915 };
1916
1917 $w = AE::timer 0.05, 0, $rcb;
1918
1919 bless \\$cb, "AnyEvent::Base::idle"
1624 } 1920 };
1921
1922 *AnyEvent::Base::idle::DESTROY = sub {
1923 undef $${$_[0]};
1924 };
1625 }; 1925 };
1926 die if $@;
1626 1927
1627 $w = AE::timer 0.05, 0, $rcb; 1928 &idle
1628
1629 bless \\$cb, "AnyEvent::Base::idle"
1630}
1631
1632sub AnyEvent::Base::idle::DESTROY {
1633 undef $${$_[0]};
1634} 1929}
1635 1930
1636package AnyEvent::CondVar; 1931package AnyEvent::CondVar;
1637 1932
1638our @ISA = AnyEvent::CondVar::Base::; 1933our @ISA = AnyEvent::CondVar::Base::;
1934
1935# only to be used for subclassing
1936sub new {
1937 my $class = shift;
1938 bless AnyEvent->condvar (@_), $class
1939}
1639 1940
1640package AnyEvent::CondVar::Base; 1941package AnyEvent::CondVar::Base;
1641 1942
1642#use overload 1943#use overload
1643# '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1944# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1653 1954
1654sub _send { 1955sub _send {
1655 # nop 1956 # nop
1656} 1957}
1657 1958
1959sub _wait {
1960 AnyEvent->_poll until $_[0]{_ae_sent};
1961}
1962
1658sub send { 1963sub send {
1659 my $cv = shift; 1964 my $cv = shift;
1660 $cv->{_ae_sent} = [@_]; 1965 $cv->{_ae_sent} = [@_];
1661 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; 1966 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1662 $cv->_send; 1967 $cv->_send;
1669 1974
1670sub ready { 1975sub ready {
1671 $_[0]{_ae_sent} 1976 $_[0]{_ae_sent}
1672} 1977}
1673 1978
1674sub _wait {
1675 $WAITING
1676 and !$_[0]{_ae_sent}
1677 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1678
1679 local $WAITING = 1;
1680 AnyEvent->one_event while !$_[0]{_ae_sent};
1681}
1682
1683sub recv { 1979sub recv {
1980 unless ($_[0]{_ae_sent}) {
1981 $WAITING
1982 and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
1983
1984 local $WAITING = 1;
1684 $_[0]->_wait; 1985 $_[0]->_wait;
1986 }
1685 1987
1686 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1988 $_[0]{_ae_croak}
1687 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1989 and Carp::croak $_[0]{_ae_croak};
1990
1991 wantarray
1992 ? @{ $_[0]{_ae_sent} }
1993 : $_[0]{_ae_sent}[0]
1688} 1994}
1689 1995
1690sub cb { 1996sub cb {
1691 my $cv = shift; 1997 my $cv = shift;
1692 1998
1708 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; 2014 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1709} 2015}
1710 2016
1711# undocumented/compatibility with pre-3.4 2017# undocumented/compatibility with pre-3.4
1712*broadcast = \&send; 2018*broadcast = \&send;
1713*wait = \&_wait; 2019*wait = \&recv;
1714 2020
1715=head1 ERROR AND EXCEPTION HANDLING 2021=head1 ERROR AND EXCEPTION HANDLING
1716 2022
1717In general, AnyEvent does not do any error handling - it relies on the 2023In general, AnyEvent does not do any error handling - it relies on the
1718caller to do that if required. The L<AnyEvent::Strict> module (see also 2024caller to do that if required. The L<AnyEvent::Strict> module (see also
1730$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and 2036$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1731so on. 2037so on.
1732 2038
1733=head1 ENVIRONMENT VARIABLES 2039=head1 ENVIRONMENT VARIABLES
1734 2040
1735The following environment variables are used by this module or its 2041AnyEvent supports a number of environment variables that tune the
1736submodules. 2042runtime behaviour. They are usually evaluated when AnyEvent is
2043loaded, initialised, or a submodule that uses them is loaded. Many of
2044them also cause AnyEvent to load additional modules - for example,
2045C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
2046loaded.
1737 2047
1738Note that AnyEvent will remove I<all> environment variables starting with 2048All the environment variables documented here start with
1739C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is 2049C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1740enabled. 2050namespace. Other modules are encouraged (but by no means required) to use
2051C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
2052namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
2053be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
2054variables starting with C<AE_>, see below).
2055
2056All variables can also be set via the C<AE_> prefix, that is, instead
2057of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
2058case there is a clash btween anyevent and another program that uses
2059C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
2060variable to the empty string, as those variables take precedence.
2061
2062When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
2063to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
2064exists. If taint mode is on, then AnyEvent will remove I<all> environment
2065variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
2066with C<undef> or the empty string, if the corresaponding C<AE_> variable
2067is set).
2068
2069The exact algorithm is currently:
2070
2071 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
2072 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
2073 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
2074
2075This ensures that child processes will not see the C<AE_> variables.
2076
2077The following environment variables are currently known to AnyEvent:
1741 2078
1742=over 4 2079=over 4
1743 2080
1744=item C<PERL_ANYEVENT_VERBOSE> 2081=item C<PERL_ANYEVENT_VERBOSE>
1745 2082
1746By default, AnyEvent will be completely silent except in fatal 2083By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1747conditions. You can set this environment variable to make AnyEvent more 2084higher (see L<AnyEvent::Log>). You can set this environment variable to a
1748talkative. 2085numerical loglevel to make AnyEvent more (or less) talkative.
1749 2086
2087If you want to do more than just set the global logging level
2088you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
2089complex specifications.
2090
2091When set to C<0> (C<off>), then no messages whatsoever will be logged with
2092everything else at defaults.
2093
1750When set to C<1> or higher, causes AnyEvent to warn about unexpected 2094When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1751conditions, such as not being able to load the event model specified by 2095conditions, such as not being able to load the event model specified by
1752C<PERL_ANYEVENT_MODEL>. 2096C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
2097is the minimum recommended level for use during development.
1753 2098
1754When set to C<2> or higher, cause AnyEvent to report to STDERR which event 2099When set to C<7> or higher (info), AnyEvent reports which event model it
1755model it chooses. 2100chooses.
1756 2101
1757When set to C<8> or higher, then AnyEvent will report extra information on 2102When set to C<8> or higher (debug), then AnyEvent will report extra
1758which optional modules it loads and how it implements certain features. 2103information on which optional modules it loads and how it implements
2104certain features.
2105
2106=item C<PERL_ANYEVENT_LOG>
2107
2108Accepts rather complex logging specifications. For example, you could log
2109all C<debug> messages of some module to stderr, warnings and above to
2110stderr, and errors and above to syslog, with:
2111
2112 PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
2113
2114For the rather extensive details, see L<AnyEvent::Log>.
2115
2116This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
2117so will take effect even before AnyEvent has initialised itself.
2118
2119Note that specifying this environment variable causes the L<AnyEvent::Log>
2120module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
2121using the latter saves a few hundred kB of memory unless a module
2122explicitly needs the extra features of AnyEvent::Log.
1759 2123
1760=item C<PERL_ANYEVENT_STRICT> 2124=item C<PERL_ANYEVENT_STRICT>
1761 2125
1762AnyEvent does not do much argument checking by default, as thorough 2126AnyEvent does not do much argument checking by default, as thorough
1763argument checking is very costly. Setting this variable to a true value 2127argument checking is very costly. Setting this variable to a true value
1765check the arguments passed to most method calls. If it finds any problems, 2129check the arguments passed to most method calls. If it finds any problems,
1766it will croak. 2130it will croak.
1767 2131
1768In other words, enables "strict" mode. 2132In other words, enables "strict" mode.
1769 2133
1770Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense> 2134Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1771>>, it is definitely recommended to keep it off in production. Keeping 2135>>, it is definitely recommended to keep it off in production. Keeping
1772C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs 2136C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1773can be very useful, however. 2137can be very useful, however.
1774 2138
2139=item C<PERL_ANYEVENT_DEBUG_SHELL>
2140
2141If this env variable is nonempty, then its contents will be interpreted by
2142C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
2143replacing every occurance of C<$$> by the process pid). The shell object
2144is saved in C<$AnyEvent::Debug::SHELL>.
2145
2146This happens when the first watcher is created.
2147
2148For example, to bind a debug shell on a unix domain socket in
2149F<< /tmp/debug<pid>.sock >>, you could use this:
2150
2151 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
2152 # connect with e.g.: socat readline /tmp/debug123.sock
2153
2154Or to bind to tcp port 4545 on localhost:
2155
2156 PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
2157 # connect with e.g.: telnet localhost 4545
2158
2159Note that creating sockets in F</tmp> or on localhost is very unsafe on
2160multiuser systems.
2161
2162=item C<PERL_ANYEVENT_DEBUG_WRAP>
2163
2164Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
2165debugging purposes. See C<AnyEvent::Debug::wrap> for details.
2166
1775=item C<PERL_ANYEVENT_MODEL> 2167=item C<PERL_ANYEVENT_MODEL>
1776 2168
1777This can be used to specify the event model to be used by AnyEvent, before 2169This can be used to specify the event model to be used by AnyEvent, before
1778auto detection and -probing kicks in. It must be a string consisting 2170auto detection and -probing kicks in.
1779entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 2171
2172It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
2173or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1780and the resulting module name is loaded and if the load was successful, 2174resulting module name is loaded and - if the load was successful - used as
1781used as event model. If it fails to load AnyEvent will proceed with 2175event model backend. If it fails to load then AnyEvent will proceed with
1782auto detection and -probing. 2176auto detection and -probing.
1783 2177
1784This functionality might change in future versions. 2178If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
2179nothing gets prepended and the module name is used as-is (hint: C<::> at
2180the end of a string designates a module name and quotes it appropriately).
1785 2181
1786For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 2182For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1787could start your program like this: 2183could start your program like this:
1788 2184
1789 PERL_ANYEVENT_MODEL=Perl perl ... 2185 PERL_ANYEVENT_MODEL=Perl perl ...
2186
2187=item C<PERL_ANYEVENT_IO_MODEL>
2188
2189The current file I/O model - see L<AnyEvent::IO> for more info.
2190
2191At the moment, only C<Perl> (small, pure-perl, synchronous) and
2192C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
2193L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1790 2194
1791=item C<PERL_ANYEVENT_PROTOCOLS> 2195=item C<PERL_ANYEVENT_PROTOCOLS>
1792 2196
1793Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences 2197Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1794for IPv4 or IPv6. The default is unspecified (and might change, or be the result 2198for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1807but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 2211but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1808- only support IPv4, never try to resolve or contact IPv6 2212- only support IPv4, never try to resolve or contact IPv6
1809addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 2213addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1810IPv6, but prefer IPv6 over IPv4. 2214IPv6, but prefer IPv6 over IPv4.
1811 2215
2216=item C<PERL_ANYEVENT_HOSTS>
2217
2218This variable, if specified, overrides the F</etc/hosts> file used by
2219L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
2220from that file instead.
2221
1812=item C<PERL_ANYEVENT_EDNS0> 2222=item C<PERL_ANYEVENT_EDNS0>
1813 2223
1814Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension 2224Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1815for DNS. This extension is generally useful to reduce DNS traffic, but 2225DNS. This extension is generally useful to reduce DNS traffic, especially
1816some (broken) firewalls drop such DNS packets, which is why it is off by 2226when DNSSEC is involved, but some (broken) firewalls drop such DNS
1817default. 2227packets, which is why it is off by default.
1818 2228
1819Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 2229Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1820EDNS0 in its DNS requests. 2230EDNS0 in its DNS requests.
1821 2231
1822=item C<PERL_ANYEVENT_MAX_FORKS> 2232=item C<PERL_ANYEVENT_MAX_FORKS>
1828 2238
1829The default value for the C<max_outstanding> parameter for the default DNS 2239The default value for the C<max_outstanding> parameter for the default DNS
1830resolver - this is the maximum number of parallel DNS requests that are 2240resolver - this is the maximum number of parallel DNS requests that are
1831sent to the DNS server. 2241sent to the DNS server.
1832 2242
2243=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
2244
2245Perl has inherently racy signal handling (you can basically choose between
2246losing signals and memory corruption) - pure perl event loops (including
2247C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
2248have to poll regularly to avoid losing signals.
2249
2250Some event loops are racy, but don't poll regularly, and some event loops
2251are written in C but are still racy. For those event loops, AnyEvent
2252installs a timer that regularly wakes up the event loop.
2253
2254By default, the interval for this timer is C<10> seconds, but you can
2255override this delay with this environment variable (or by setting
2256the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
2257watchers).
2258
2259Lower values increase CPU (and energy) usage, higher values can introduce
2260long delays when reaping children or waiting for signals.
2261
2262The L<AnyEvent::Async> module, if available, will be used to avoid this
2263polling (with most event loops).
2264
1833=item C<PERL_ANYEVENT_RESOLV_CONF> 2265=item C<PERL_ANYEVENT_RESOLV_CONF>
1834 2266
1835The file to use instead of F</etc/resolv.conf> (or OS-specific 2267The absolute path to a F<resolv.conf>-style file to use instead of
1836configuration) in the default resolver. When set to the empty string, no 2268F</etc/resolv.conf> (or the OS-specific configuration) in the default
1837default config will be used. 2269resolver, or the empty string to select the default configuration.
1838 2270
1839=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. 2271=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1840 2272
1841When neither C<ca_file> nor C<ca_path> was specified during 2273When neither C<ca_file> nor C<ca_path> was specified during
1842L<AnyEvent::TLS> context creation, and either of these environment 2274L<AnyEvent::TLS> context creation, and either of these environment
1843variables exist, they will be used to specify CA certificate locations 2275variables are nonempty, they will be used to specify CA certificate
1844instead of a system-dependent default. 2276locations instead of a system-dependent default.
1845 2277
1846=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT> 2278=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1847 2279
1848When these are set to C<1>, then the respective modules are not 2280When these are set to C<1>, then the respective modules are not
1849loaded. Mostly good for testing AnyEvent itself. 2281loaded. Mostly good for testing AnyEvent itself.
1912 warn "read: $input\n"; # output what has been read 2344 warn "read: $input\n"; # output what has been read
1913 $cv->send if $input =~ /^q/i; # quit program if /^q/i 2345 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1914 }, 2346 },
1915 ); 2347 );
1916 2348
1917 my $time_watcher; # can only be used once
1918
1919 sub new_timer {
1920 $timer = AnyEvent->timer (after => 1, cb => sub { 2349 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1921 warn "timeout\n"; # print 'timeout' about every second 2350 warn "timeout\n"; # print 'timeout' at most every second
1922 &new_timer; # and restart the time
1923 }); 2351 });
1924 }
1925
1926 new_timer; # create first timer
1927 2352
1928 $cv->recv; # wait until user enters /^q/i 2353 $cv->recv; # wait until user enters /^q/i
1929 2354
1930=head1 REAL-WORLD EXAMPLE 2355=head1 REAL-WORLD EXAMPLE
1931 2356
2004 2429
2005The actual code goes further and collects all errors (C<die>s, exceptions) 2430The actual code goes further and collects all errors (C<die>s, exceptions)
2006that occurred during request processing. The C<result> method detects 2431that occurred during request processing. The C<result> method detects
2007whether an exception as thrown (it is stored inside the $txn object) 2432whether an exception as thrown (it is stored inside the $txn object)
2008and just throws the exception, which means connection errors and other 2433and just throws the exception, which means connection errors and other
2009problems get reported tot he code that tries to use the result, not in a 2434problems get reported to the code that tries to use the result, not in a
2010random callback. 2435random callback.
2011 2436
2012All of this enables the following usage styles: 2437All of this enables the following usage styles:
2013 2438
20141. Blocking: 24391. Blocking:
2188(even when used without AnyEvent), but most event loops have acceptable 2613(even when used without AnyEvent), but most event loops have acceptable
2189performance with or without AnyEvent. 2614performance with or without AnyEvent.
2190 2615
2191=item * The overhead AnyEvent adds is usually much smaller than the overhead of 2616=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2192the actual event loop, only with extremely fast event loops such as EV 2617the actual event loop, only with extremely fast event loops such as EV
2193adds AnyEvent significant overhead. 2618does AnyEvent add significant overhead.
2194 2619
2195=item * You should avoid POE like the plague if you want performance or 2620=item * You should avoid POE like the plague if you want performance or
2196reasonable memory usage. 2621reasonable memory usage.
2197 2622
2198=back 2623=back
2375As you can see, the AnyEvent + EV combination even beats the 2800As you can see, the AnyEvent + EV combination even beats the
2376hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl 2801hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2377backend easily beats IO::Lambda and POE. 2802backend easily beats IO::Lambda and POE.
2378 2803
2379And even the 100% non-blocking version written using the high-level (and 2804And even the 100% non-blocking version written using the high-level (and
2380slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a 2805slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2381large margin, even though it does all of DNS, tcp-connect and socket I/O 2806higher level ("unoptimised") abstractions by a large margin, even though
2382in a non-blocking way. 2807it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2383 2808
2384The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and 2809The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2385F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are 2810F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2386part of the IO::lambda distribution and were used without any changes. 2811part of the IO::Lambda distribution and were used without any changes.
2387 2812
2388 2813
2389=head1 SIGNALS 2814=head1 SIGNALS
2390 2815
2391AnyEvent currently installs handlers for these signals: 2816AnyEvent currently installs handlers for these signals:
2428 unless defined $SIG{PIPE}; 2853 unless defined $SIG{PIPE};
2429 2854
2430=head1 RECOMMENDED/OPTIONAL MODULES 2855=head1 RECOMMENDED/OPTIONAL MODULES
2431 2856
2432One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and 2857One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2433it's built-in modules) are required to use it. 2858its built-in modules) are required to use it.
2434 2859
2435That does not mean that AnyEvent won't take advantage of some additional 2860That does not mean that AnyEvent won't take advantage of some additional
2436modules if they are installed. 2861modules if they are installed.
2437 2862
2438This section epxlains which additional modules will be used, and how they 2863This section explains which additional modules will be used, and how they
2439affect AnyEvent's operetion. 2864affect AnyEvent's operation.
2440 2865
2441=over 4 2866=over 4
2442 2867
2443=item L<Async::Interrupt> 2868=item L<Async::Interrupt>
2444 2869
2449catch the signals) with some delay (default is 10 seconds, look for 2874catch the signals) with some delay (default is 10 seconds, look for
2450C<$AnyEvent::MAX_SIGNAL_LATENCY>). 2875C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2451 2876
2452If this module is available, then it will be used to implement signal 2877If this module is available, then it will be used to implement signal
2453catching, which means that signals will not be delayed, and the event loop 2878catching, which means that signals will not be delayed, and the event loop
2454will not be interrupted regularly, which is more efficient (And good for 2879will not be interrupted regularly, which is more efficient (and good for
2455battery life on laptops). 2880battery life on laptops).
2456 2881
2457This affects not just the pure-perl event loop, but also other event loops 2882This affects not just the pure-perl event loop, but also other event loops
2458that have no signal handling on their own (e.g. Glib, Tk, Qt). 2883that have no signal handling on their own (e.g. Glib, Tk, Qt).
2459 2884
2471automatic timer adjustments even when no monotonic clock is available, 2896automatic timer adjustments even when no monotonic clock is available,
2472can take avdantage of advanced kernel interfaces such as C<epoll> and 2897can take avdantage of advanced kernel interfaces such as C<epoll> and
2473C<kqueue>, and is the fastest backend I<by far>. You can even embed 2898C<kqueue>, and is the fastest backend I<by far>. You can even embed
2474L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>). 2899L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2475 2900
2901If you only use backends that rely on another event loop (e.g. C<Tk>),
2902then this module will do nothing for you.
2903
2476=item L<Guard> 2904=item L<Guard>
2477 2905
2478The guard module, when used, will be used to implement 2906The guard module, when used, will be used to implement
2479C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a 2907C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2480lot less memory), but otherwise doesn't affect guard operation much. It is 2908lot less memory), but otherwise doesn't affect guard operation much. It is
2481purely used for performance. 2909purely used for performance.
2482 2910
2483=item L<JSON> and L<JSON::XS> 2911=item L<JSON> and L<JSON::XS>
2484 2912
2485This module is required when you want to read or write JSON data via 2913One of these modules is required when you want to read or write JSON data
2486L<AnyEvent::Handle>. It is also written in pure-perl, but can take 2914via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2487advantage of the ultra-high-speed L<JSON::XS> module when it is installed. 2915advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2488
2489In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2490installed.
2491 2916
2492=item L<Net::SSLeay> 2917=item L<Net::SSLeay>
2493 2918
2494Implementing TLS/SSL in Perl is certainly interesting, but not very 2919Implementing TLS/SSL in Perl is certainly interesting, but not very
2495worthwhile: If this module is installed, then L<AnyEvent::Handle> (with 2920worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2496the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL. 2921the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2497 2922
2498=item L<Time::HiRes> 2923=item L<Time::HiRes>
2499 2924
2500This module is part of perl since release 5.008. It will be used when the 2925This module is part of perl since release 5.008. It will be used when the
2501chosen event library does not come with a timing source on it's own. The 2926chosen event library does not come with a timing source of its own. The
2502pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to 2927pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2503try to use a monotonic clock for timing stability. 2928try to use a monotonic clock for timing stability.
2504 2929
2505=back 2930=back
2506 2931
2507 2932
2508=head1 FORK 2933=head1 FORK
2509 2934
2510Most event libraries are not fork-safe. The ones who are usually are 2935Most event libraries are not fork-safe. The ones who are usually are
2511because they rely on inefficient but fork-safe C<select> or C<poll> 2936because they rely on inefficient but fork-safe C<select> or C<poll> calls
2512calls. Only L<EV> is fully fork-aware. 2937- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2938are usually badly thought-out hacks that are incompatible with fork in
2939one way or another. Only L<EV> is fully fork-aware and ensures that you
2940continue event-processing in both parent and child (or both, if you know
2941what you are doing).
2942
2943This means that, in general, you cannot fork and do event processing in
2944the child if the event library was initialised before the fork (which
2945usually happens when the first AnyEvent watcher is created, or the library
2946is loaded).
2513 2947
2514If you have to fork, you must either do so I<before> creating your first 2948If you have to fork, you must either do so I<before> creating your first
2515watcher OR you must not use AnyEvent at all in the child OR you must do 2949watcher OR you must not use AnyEvent at all in the child OR you must do
2516something completely out of the scope of AnyEvent. 2950something completely out of the scope of AnyEvent.
2951
2952The problem of doing event processing in the parent I<and> the child
2953is much more complicated: even for backends that I<are> fork-aware or
2954fork-safe, their behaviour is not usually what you want: fork clones all
2955watchers, that means all timers, I/O watchers etc. are active in both
2956parent and child, which is almost never what you want. USing C<exec>
2957to start worker children from some kind of manage rprocess is usually
2958preferred, because it is much easier and cleaner, at the expense of having
2959to have another binary.
2517 2960
2518 2961
2519=head1 SECURITY CONSIDERATIONS 2962=head1 SECURITY CONSIDERATIONS
2520 2963
2521AnyEvent can be forced to load any event model via 2964AnyEvent can be forced to load any event model via
2551pronounced). 2994pronounced).
2552 2995
2553 2996
2554=head1 SEE ALSO 2997=head1 SEE ALSO
2555 2998
2556Utility functions: L<AnyEvent::Util>. 2999Tutorial/Introduction: L<AnyEvent::Intro>.
2557 3000
2558Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 3001FAQ: L<AnyEvent::FAQ>.
2559L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 3002
3003Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
3004(simply logging).
3005
3006Development/Debugging: L<AnyEvent::Strict> (stricter checking),
3007L<AnyEvent::Debug> (interactive shell, watcher tracing).
3008
3009Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
3010L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
3011L<Qt>, L<POE>, L<FLTK>.
2560 3012
2561Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 3013Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2562L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 3014L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2563L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 3015L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2564L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>. 3016L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
3017L<AnyEvent::Impl::FLTK>.
2565 3018
2566Non-blocking file handles, sockets, TCP clients and 3019Non-blocking handles, pipes, stream sockets, TCP clients and
2567servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 3020servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2568 3021
3022Asynchronous File I/O: L<AnyEvent::IO>.
3023
2569Asynchronous DNS: L<AnyEvent::DNS>. 3024Asynchronous DNS: L<AnyEvent::DNS>.
2570 3025
2571Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, 3026Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2572L<Coro::Event>,
2573 3027
2574Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>, 3028Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2575L<AnyEvent::HTTP>. 3029L<AnyEvent::HTTP>.
2576 3030
2577 3031
2578=head1 AUTHOR 3032=head1 AUTHOR
2579 3033
2580 Marc Lehmann <schmorp@schmorp.de> 3034 Marc Lehmann <schmorp@schmorp.de>
2581 http://home.schmorp.de/ 3035 http://anyevent.schmorp.de
2582 3036
2583=cut 3037=cut
2584 3038
25851 30391
2586 3040

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