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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 $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
400 411
412=head3 Restart Behaviour
413
414While restart behaviour is up to the event loop implementation, most will
415not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
416pure perl implementation).
417
418=head3 Safe/Unsafe Signals
419
420Perl signals can be either "safe" (synchronous to opcode handling) or
421"unsafe" (asynchronous) - the former might get delayed indefinitely, the
422latter might corrupt your memory.
423
424AnyEvent signal handlers are, in addition, synchronous to the event loop,
425i.e. they will not interrupt your running perl program but will only be
426called as part of the normal event handling (just like timer, I/O etc.
427callbacks, too).
428
401=head3 Signal Races, Delays and Workarounds 429=head3 Signal Races, Delays and Workarounds
402 430
403Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching 431Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
404callbacks to signals in a generic way, which is a pity, as you cannot 432callbacks to signals in a generic way, which is a pity, as you cannot
405do race-free signal handling in perl, requiring C libraries for 433do race-free signal handling in perl, requiring C libraries for
406this. AnyEvent will try to do it's best, which means in some cases, 434this. AnyEvent will try to do its best, which means in some cases,
407signals will be delayed. The maximum time a signal might be delayed is 435signals will be delayed. The maximum time a signal might be delayed is
408specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This 436specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
409variable can be changed only before the first signal watcher is created, 437variable can be changed only before the first signal watcher is created,
410and should be left alone otherwise. This variable determines how often 438and should be left alone otherwise. This variable determines how often
411AnyEvent polls for signals (in case a wake-up was missed). Higher values 439AnyEvent polls for signals (in case a wake-up was missed). Higher values
413saving. 441saving.
414 442
415All these problems can be avoided by installing the optional 443All these problems can be avoided by installing the optional
416L<Async::Interrupt> module, which works with most event loops. It will not 444L<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> 445work 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 446(and not with L<POE> currently, as POE does its own workaround with
419one-second latency). For those, you just have to suffer the delays. 447one-second latency). For those, you just have to suffer the delays.
420 448
421=head2 CHILD PROCESS WATCHERS 449=head2 CHILD PROCESS WATCHERS
422 450
423 $w = AnyEvent->child (pid => <process id>, cb => <callback>); 451 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
424 452
425You can also watch on a child process exit and catch its exit status. 453You can also watch for a child process exit and catch its exit status.
426 454
427The child process is specified by the C<pid> argument (one some backends, 455The 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 456using C<0> watches for any child process exit, on others this will
429croak). The watcher will be triggered only when the child process has 457croak). The watcher will be triggered only when the child process has
430finished and an exit status is available, not on any trace events 458finished and an exit status is available, not on any trace events
431(stopped/continued). 459(stopped/continued).
432 460
454thing in an AnyEvent program, you I<have> to create at least one 482thing in an AnyEvent program, you I<have> to create at least one
455watcher before you C<fork> the child (alternatively, you can call 483watcher before you C<fork> the child (alternatively, you can call
456C<AnyEvent::detect>). 484C<AnyEvent::detect>).
457 485
458As most event loops do not support waiting for child events, they will be 486As 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 487emulated by AnyEvent in most cases, in which case the latency and race
460mentioned in the description of signal watchers apply. 488problems mentioned in the description of signal watchers apply.
461 489
462Example: fork a process and wait for it 490Example: fork a process and wait for it
463 491
464 my $done = AnyEvent->condvar; 492 my $done = AnyEvent->condvar;
465 493
479 507
480=head2 IDLE WATCHERS 508=head2 IDLE WATCHERS
481 509
482 $w = AnyEvent->idle (cb => <callback>); 510 $w = AnyEvent->idle (cb => <callback>);
483 511
484Sometimes there is a need to do something, but it is not so important 512This will repeatedly invoke the callback after the process becomes idle,
485to do it instantly, but only when there is nothing better to do. This 513until 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".
488 514
489Idle watchers ideally get invoked when the event loop has nothing 515Idle 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 516is not so important (or wise) to do it instantly. The callback will be
491events. Instead of blocking, the idle watcher is invoked. 517invoked only when there is "nothing better to do", which is usually
518defined as "all outstanding events have been handled and no new events
519have been detected". That means that idle watchers ideally get invoked
520when the event loop has just polled for new events but none have been
521detected. Instead of blocking to wait for more events, the idle watchers
522will be invoked.
492 523
493Most event loops unfortunately do not really support idle watchers (only 524Unfortunately, most event loops do not really support idle watchers (only
494EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent 525EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
495will simply call the callback "from time to time". 526will simply call the callback "from time to time".
496 527
497Example: read lines from STDIN, but only process them when the 528Example: read lines from STDIN, but only process them when the
498program is otherwise idle: 529program is otherwise idle:
526will actively watch for new events and call your callbacks. 557will actively watch for new events and call your callbacks.
527 558
528AnyEvent is slightly different: it expects somebody else to run the event 559AnyEvent is slightly different: it expects somebody else to run the event
529loop and will only block when necessary (usually when told by the user). 560loop and will only block when necessary (usually when told by the user).
530 561
531The instrument to do that is called a "condition variable", so called 562The tool to do that is called a "condition variable", so called because
532because they represent a condition that must become true. 563they represent a condition that must become true.
533 564
534Now is probably a good time to look at the examples further below. 565Now is probably a good time to look at the examples further below.
535 566
536Condition variables can be created by calling the C<< AnyEvent->condvar 567Condition variables can be created by calling the C<< AnyEvent->condvar
537>> method, usually without arguments. The only argument pair allowed is 568>> method, usually without arguments. The only argument pair allowed is
542After creation, the condition variable is "false" until it becomes "true" 573After creation, the condition variable is "false" until it becomes "true"
543by calling the C<send> method (or calling the condition variable as if it 574by 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<< 575were a callback, read about the caveats in the description for the C<<
545->send >> method). 576->send >> method).
546 577
547Condition variables are similar to callbacks, except that you can 578Since 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 579some 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 580
550another way to call them is transactions - each condition variable can be 581=over 4
551used to represent a transaction, which finishes at some point and delivers 582
552a result. And yet some people know them as "futures" - a promise to 583=item * Condition variables are like callbacks - you can call them (and pass them instead
553compute/deliver something that you can wait for. 584of callbacks). Unlike callbacks however, you can also wait for them to be called.
585
586=item * Condition variables are signals - one side can emit or send them,
587the other side can wait for them, or install a handler that is called when
588the signal fires.
589
590=item * Condition variables are like "Merge Points" - points in your program
591where you merge multiple independent results/control flows into one.
592
593=item * Condition variables represent a transaction - functions that start
594some kind of transaction can return them, leaving the caller the choice
595between waiting in a blocking fashion, or setting a callback.
596
597=item * Condition variables represent future values, or promises to deliver
598some result, long before the result is available.
599
600=back
554 601
555Condition variables are very useful to signal that something has finished, 602Condition variables are very useful to signal that something has finished,
556for example, if you write a module that does asynchronous http requests, 603for example, if you write a module that does asynchronous http requests,
557then a condition variable would be the ideal candidate to signal the 604then a condition variable would be the ideal candidate to signal the
558availability of results. The user can either act when the callback is 605availability of results. The user can either act when the callback is
571 618
572Condition variables are represented by hash refs in perl, and the keys 619Condition variables are represented by hash refs in perl, and the keys
573used by AnyEvent itself are all named C<_ae_XXX> to make subclassing 620used 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 621easy (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 622AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
576it's C<new> method in your own C<new> method. 623its C<new> method in your own C<new> method.
577 624
578There are two "sides" to a condition variable - the "producer side" which 625There are two "sides" to a condition variable - the "producer side" which
579eventually calls C<< -> send >>, and the "consumer side", which waits 626eventually calls C<< -> send >>, and the "consumer side", which waits
580for the send to occur. 627for the send to occur.
581 628
582Example: wait for a timer. 629Example: wait for a timer.
583 630
584 # wait till the result is ready 631 # condition: "wait till the timer is fired"
585 my $result_ready = AnyEvent->condvar; 632 my $timer_fired = AnyEvent->condvar;
586 633
587 # do something such as adding a timer 634 # create the timer - we could wait for, say
588 # or socket watcher the calls $result_ready->send 635 # a handle becomign ready, or even an
589 # when the "result" is ready. 636 # AnyEvent::HTTP request to finish, but
590 # in this case, we simply use a timer: 637 # in this case, we simply use a timer:
591 my $w = AnyEvent->timer ( 638 my $w = AnyEvent->timer (
592 after => 1, 639 after => 1,
593 cb => sub { $result_ready->send }, 640 cb => sub { $timer_fired->send },
594 ); 641 );
595 642
596 # this "blocks" (while handling events) till the callback 643 # this "blocks" (while handling events) till the callback
597 # calls ->send 644 # calls ->send
598 $result_ready->recv; 645 $timer_fired->recv;
599 646
600Example: wait for a timer, but take advantage of the fact that condition 647Example: wait for a timer, but take advantage of the fact that condition
601variables are also callable directly. 648variables are also callable directly.
602 649
603 my $done = AnyEvent->condvar; 650 my $done = AnyEvent->condvar;
646they were a code reference). Calling them directly is the same as calling 693they were a code reference). Calling them directly is the same as calling
647C<send>. 694C<send>.
648 695
649=item $cv->croak ($error) 696=item $cv->croak ($error)
650 697
651Similar to send, but causes all call's to C<< ->recv >> to invoke 698Similar to send, but causes all calls to C<< ->recv >> to invoke
652C<Carp::croak> with the given error message/object/scalar. 699C<Carp::croak> with the given error message/object/scalar.
653 700
654This can be used to signal any errors to the condition variable 701This can be used to signal any errors to the condition variable
655user/consumer. Doing it this way instead of calling C<croak> directly 702user/consumer. Doing it this way instead of calling C<croak> directly
656delays the error detetcion, but has the overwhelmign advantage that it 703delays the error detection, but has the overwhelming advantage that it
657diagnoses the error at the place where the result is expected, and not 704diagnoses the error at the place where the result is expected, and not
658deep in some event clalback without connection to the actual code causing 705deep in some event callback with no connection to the actual code causing
659the problem. 706the problem.
660 707
661=item $cv->begin ([group callback]) 708=item $cv->begin ([group callback])
662 709
663=item $cv->end 710=item $cv->end
701one call to C<begin>, so the condvar waits for all calls to C<end> before 748one call to C<begin>, so the condvar waits for all calls to C<end> before
702sending. 749sending.
703 750
704The ping example mentioned above is slightly more complicated, as the 751The ping example mentioned above is slightly more complicated, as the
705there are results to be passwd back, and the number of tasks that are 752there are results to be passwd back, and the number of tasks that are
706begung can potentially be zero: 753begun can potentially be zero:
707 754
708 my $cv = AnyEvent->condvar; 755 my $cv = AnyEvent->condvar;
709 756
710 my %result; 757 my %result;
711 $cv->begin (sub { shift->send (\%result) }); 758 $cv->begin (sub { shift->send (\%result) });
732to be called once the counter reaches C<0>, and second, it ensures that 779to 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 780C<send> is called even when C<no> hosts are being pinged (the loop
734doesn't execute once). 781doesn't execute once).
735 782
736This is the general pattern when you "fan out" into multiple (but 783This is the general pattern when you "fan out" into multiple (but
737potentially none) subrequests: use an outer C<begin>/C<end> pair to set 784potentially 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 785the 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, 786subrequest you start, call C<begin> and for each subrequest you finish,
740call C<end>. 787call C<end>.
741 788
742=back 789=back
749=over 4 796=over 4
750 797
751=item $cv->recv 798=item $cv->recv
752 799
753Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 800Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
754>> methods have been called on c<$cv>, while servicing other watchers 801>> methods have been called on C<$cv>, while servicing other watchers
755normally. 802normally.
756 803
757You can only wait once on a condition - additional calls are valid but 804You can only wait once on a condition - additional calls are valid but
758will return immediately. 805will return immediately.
759 806
776caller decide whether the call will block or not (for example, by coupling 823caller decide whether the call will block or not (for example, by coupling
777condition variables with some kind of request results and supporting 824condition variables with some kind of request results and supporting
778callbacks so the caller knows that getting the result will not block, 825callbacks so the caller knows that getting the result will not block,
779while still supporting blocking waits if the caller so desires). 826while still supporting blocking waits if the caller so desires).
780 827
781You can ensure that C<< -recv >> never blocks by setting a callback and 828You can ensure that C<< ->recv >> never blocks by setting a callback and
782only calling C<< ->recv >> from within that callback (or at a later 829only calling C<< ->recv >> from within that callback (or at a later
783time). This will work even when the event loop does not support blocking 830time). This will work even when the event loop does not support blocking
784waits otherwise. 831waits otherwise.
785 832
786=item $bool = $cv->ready 833=item $bool = $cv->ready
791=item $cb = $cv->cb ($cb->($cv)) 838=item $cb = $cv->cb ($cb->($cv))
792 839
793This is a mutator function that returns the callback set and optionally 840This is a mutator function that returns the callback set and optionally
794replaces it before doing so. 841replaces it before doing so.
795 842
796The callback will be called when the condition becomes (or already was) 843The 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 844C<send> or C<croak> are called, with the only argument being the
798the only argument being the condition variable itself. Calling C<recv> 845condition variable itself. If the condition is already true, the
846callback is called immediately when it is set. Calling C<recv> inside
799inside the callback or at any later time is guaranteed not to block. 847the callback or at any later time is guaranteed not to block.
800 848
801=back 849=back
802 850
803=head1 SUPPORTED EVENT LOOPS/BACKENDS 851=head1 SUPPORTED EVENT LOOPS/BACKENDS
804 852
812use. If EV is not installed, then AnyEvent will fall back to its own 860use. If EV is not installed, then AnyEvent will fall back to its own
813pure-perl implementation, which is available everywhere as it comes with 861pure-perl implementation, which is available everywhere as it comes with
814AnyEvent itself. 862AnyEvent itself.
815 863
816 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 864 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
817 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 865 AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
818 866
819=item Backends that are transparently being picked up when they are used. 867=item Backends that are transparently being picked up when they are used.
820 868
821These will be used when they are currently loaded when the first watcher 869These 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 870is created, in which case it is assumed that the application is using
823them. This means that AnyEvent will automatically pick the right backend 871them. This means that AnyEvent will automatically pick the right backend
824when the main program loads an event module before anything starts to 872when the main program loads an event module before anything starts to
825create watchers. Nothing special needs to be done by the main program. 873create watchers. Nothing special needs to be done by the main program.
826 874
828 AnyEvent::Impl::Glib based on Glib, slow but very stable. 876 AnyEvent::Impl::Glib based on Glib, slow but very stable.
829 AnyEvent::Impl::Tk based on Tk, very broken. 877 AnyEvent::Impl::Tk based on Tk, very broken.
830 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 878 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
831 AnyEvent::Impl::POE based on POE, very slow, some limitations. 879 AnyEvent::Impl::POE based on POE, very slow, some limitations.
832 AnyEvent::Impl::Irssi used when running within irssi. 880 AnyEvent::Impl::Irssi used when running within irssi.
881 AnyEvent::Impl::IOAsync based on IO::Async.
882 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
883 AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
833 884
834=item Backends with special needs. 885=item Backends with special needs.
835 886
836Qt requires the Qt::Application to be instantiated first, but will 887Qt requires the Qt::Application to be instantiated first, but will
837otherwise be picked up automatically. As long as the main program 888otherwise be picked up automatically. As long as the main program
838instantiates the application before any AnyEvent watchers are created, 889instantiates the application before any AnyEvent watchers are created,
839everything should just work. 890everything should just work.
840 891
841 AnyEvent::Impl::Qt based on Qt. 892 AnyEvent::Impl::Qt based on Qt.
842 893
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. 894=item Event loops that are indirectly supported via other backends.
852 895
853Some event loops can be supported via other modules: 896Some event loops can be supported via other modules:
854 897
855There is no direct support for WxWidgets (L<Wx>) or L<Prima>. 898There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
880Contains C<undef> until the first watcher is being created, before the 923Contains C<undef> until the first watcher is being created, before the
881backend has been autodetected. 924backend has been autodetected.
882 925
883Afterwards it contains the event model that is being used, which is the 926Afterwards 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 927name 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 928of 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 929case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
887will be C<urxvt::anyevent>). 930will be C<urxvt::anyevent>).
888 931
889=item AnyEvent::detect 932=item AnyEvent::detect
890 933
891Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 934Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
892if necessary. You should only call this function right before you would 935if necessary. You should only call this function right before you would
893have created an AnyEvent watcher anyway, that is, as late as possible at 936have created an AnyEvent watcher anyway, that is, as late as possible at
894runtime, and not e.g. while initialising of your module. 937runtime, and not e.g. during initialisation of your module.
938
939The effect of calling this function is as if a watcher had been created
940(specifically, actions that happen "when the first watcher is created"
941happen when calling detetc as well).
895 942
896If you need to do some initialisation before AnyEvent watchers are 943If you need to do some initialisation before AnyEvent watchers are
897created, use C<post_detect>. 944created, use C<post_detect>.
898 945
899=item $guard = AnyEvent::post_detect { BLOCK } 946=item $guard = AnyEvent::post_detect { BLOCK }
900 947
901Arranges for the code block to be executed as soon as the event model is 948Arranges for the code block to be executed as soon as the event model is
902autodetected (or immediately if this has already happened). 949autodetected (or immediately if that has already happened).
903 950
904The block will be executed I<after> the actual backend has been detected 951The block will be executed I<after> the actual backend has been detected
905(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been 952(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
906created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do 953created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
907other initialisations - see the sources of L<AnyEvent::Strict> or 954other initialisations - see the sources of L<AnyEvent::Strict> or
916that automatically removes the callback again when it is destroyed (or 963that automatically removes the callback again when it is destroyed (or
917C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for 964C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
918a case where this is useful. 965a case where this is useful.
919 966
920Example: Create a watcher for the IO::AIO module and store it in 967Example: Create a watcher for the IO::AIO module and store it in
921C<$WATCHER>. Only do so after the event loop is initialised, though. 968C<$WATCHER>, but do so only do so after the event loop is initialised.
922 969
923 our WATCHER; 970 our WATCHER;
924 971
925 my $guard = AnyEvent::post_detect { 972 my $guard = AnyEvent::post_detect {
926 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); 973 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
934 $WATCHER ||= $guard; 981 $WATCHER ||= $guard;
935 982
936=item @AnyEvent::post_detect 983=item @AnyEvent::post_detect
937 984
938If there are any code references in this array (you can C<push> to it 985If there are any code references in this array (you can C<push> to it
939before or after loading AnyEvent), then they will called directly after 986before or after loading AnyEvent), then they will be called directly
940the event loop has been chosen. 987after the event loop has been chosen.
941 988
942You should check C<$AnyEvent::MODEL> before adding to this array, though: 989You 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 990if it is defined then the event loop has already been detected, and the
944array will be ignored. 991array will be ignored.
945 992
946Best use C<AnyEvent::post_detect { BLOCK }> when your application allows 993Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
947it,as it takes care of these details. 994it, as it takes care of these details.
948 995
949This variable is mainly useful for modules that can do something useful 996This 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 997when 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 998not need to even load it by default. This array provides the means to hook
952into AnyEvent passively, without loading it. 999into AnyEvent passively, without loading it.
953 1000
1001Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
1002together, you could put this into Coro (this is the actual code used by
1003Coro to accomplish this):
1004
1005 if (defined $AnyEvent::MODEL) {
1006 # AnyEvent already initialised, so load Coro::AnyEvent
1007 require Coro::AnyEvent;
1008 } else {
1009 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
1010 # as soon as it is
1011 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
1012 }
1013
1014=item AnyEvent::postpone { BLOCK }
1015
1016Arranges for the block to be executed as soon as possible, but not before
1017the call itself returns. In practise, the block will be executed just
1018before the event loop polls for new events, or shortly afterwards.
1019
1020This function never returns anything (to make the C<return postpone { ...
1021}> idiom more useful.
1022
1023To understand the usefulness of this function, consider a function that
1024asynchronously does something for you and returns some transaction
1025object or guard to let you cancel the operation. For example,
1026C<AnyEvent::Socket::tcp_connect>:
1027
1028 # start a conenction attempt unless one is active
1029 $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
1030 delete $self->{connect_guard};
1031 ...
1032 };
1033
1034Imagine that this function could instantly call the callback, for
1035example, because it detects an obvious error such as a negative port
1036number. Invoking the callback before the function returns causes problems
1037however: the callback will be called and will try to delete the guard
1038object. But since the function hasn't returned yet, there is nothing to
1039delete. When the function eventually returns it will assign the guard
1040object to C<< $self->{connect_guard} >>, where it will likely never be
1041deleted, so the program thinks it is still trying to connect.
1042
1043This is where C<AnyEvent::postpone> should be used. Instead of calling the
1044callback directly on error:
1045
1046 $cb->(undef), return # signal error to callback, BAD!
1047 if $some_error_condition;
1048
1049It should use C<postpone>:
1050
1051 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1052 if $some_error_condition;
1053
1054=item AnyEvent::log $level, $msg[, @args]
1055
1056Log the given C<$msg> at the given C<$level>.
1057
1058If L<AnyEvent::Log> is not loaded then this function makes a simple test
1059to see whether the message will be logged. If the test succeeds it will
1060load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
1061the L<AnyEvent::Log> documentation for details.
1062
1063If the test fails it will simply return.
1064
1065If you want to sprinkle loads of logging calls around your code, consider
1066creating a logger callback with the C<AnyEvent::Log::logger> function,
1067which can reduce typing, codesize and can reduce the logging overhead
1068enourmously.
1069
954=back 1070=back
955 1071
956=head1 WHAT TO DO IN A MODULE 1072=head1 WHAT TO DO IN A MODULE
957 1073
958As a module author, you should C<use AnyEvent> and call AnyEvent methods 1074As 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 1084because it will stall the whole program, and the whole point of using
969events is to stay interactive. 1085events is to stay interactive.
970 1086
971It is fine, however, to call C<< ->recv >> when the user of your module 1087It 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 1088requests 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 >> 1089called C<results> that returns the results, it may call C<< ->recv >>
974freely, as the user of your module knows what she is doing. always). 1090freely, as the user of your module knows what she is doing. Always).
975 1091
976=head1 WHAT TO DO IN THE MAIN PROGRAM 1092=head1 WHAT TO DO IN THE MAIN PROGRAM
977 1093
978There will always be a single main program - the only place that should 1094There will always be a single main program - the only place that should
979dictate which event model to use. 1095dictate which event model to use.
980 1096
981If it doesn't care, it can just "use AnyEvent" and use it itself, or not 1097If 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 1098when it depends on a module that uses an AnyEvent. If the program itself
983decide which implementation to chose if some module relies on it. 1099uses AnyEvent, but does not care which event loop is used, all it needs
1100to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
1101available loop implementation.
984 1102
985If the main program relies on a specific event model - for example, in 1103If 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 1104Gtk2 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 1105event module before loading AnyEvent or any module that uses it: generally
988speaking, you should load it as early as possible. The reason is that 1106speaking, you should load it as early as possible. The reason is that
989modules might create watchers when they are loaded, and AnyEvent will 1107modules 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 1108decide 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. 1109might choose the wrong one unless you load the correct one yourself.
992 1110
993You can chose to use a pure-perl implementation by loading the 1111You can chose to use a pure-perl implementation by loading the
994C<AnyEvent::Impl::Perl> module, which gives you similar behaviour 1112C<AnyEvent::Loop> module, which gives you similar behaviour
995everywhere, but letting AnyEvent chose the model is generally better. 1113everywhere, but letting AnyEvent chose the model is generally better.
996 1114
997=head2 MAINLOOP EMULATION 1115=head2 MAINLOOP EMULATION
998 1116
999Sometimes (often for short test scripts, or even standalone programs who 1117Sometimes (often for short test scripts, or even standalone programs who
1012 1130
1013 1131
1014=head1 OTHER MODULES 1132=head1 OTHER MODULES
1015 1133
1016The following is a non-exhaustive list of additional modules that use 1134The following is a non-exhaustive list of additional modules that use
1017AnyEvent as a client and can therefore be mixed easily with other AnyEvent 1135AnyEvent as a client and can therefore be mixed easily with other
1018modules and other event loops in the same program. Some of the modules 1136AnyEvent modules and other event loops in the same program. Some of the
1019come with AnyEvent, most are available via CPAN. 1137modules come as part of AnyEvent, the others are available via CPAN (see
1138L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
1139a longer non-exhaustive list), and the list is heavily biased towards
1140modules of the AnyEvent author himself :)
1020 1141
1021=over 4 1142=over 4
1022 1143
1023=item L<AnyEvent::Util> 1144=item L<AnyEvent::Util>
1024 1145
1025Contains various utility functions that replace often-used but blocking 1146Contains various utility functions that replace often-used blocking
1026functions such as C<inet_aton> by event-/callback-based versions. 1147functions such as C<inet_aton> with event/callback-based versions.
1027 1148
1028=item L<AnyEvent::Socket> 1149=item L<AnyEvent::Socket>
1029 1150
1030Provides various utility functions for (internet protocol) sockets, 1151Provides various utility functions for (internet protocol) sockets,
1031addresses and name resolution. Also functions to create non-blocking tcp 1152addresses and name resolution. Also functions to create non-blocking tcp
1033 1154
1034=item L<AnyEvent::Handle> 1155=item L<AnyEvent::Handle>
1035 1156
1036Provide read and write buffers, manages watchers for reads and writes, 1157Provide read and write buffers, manages watchers for reads and writes,
1037supports raw and formatted I/O, I/O queued and fully transparent and 1158supports raw and formatted I/O, I/O queued and fully transparent and
1038non-blocking SSL/TLS (via L<AnyEvent::TLS>. 1159non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1039 1160
1040=item L<AnyEvent::DNS> 1161=item L<AnyEvent::DNS>
1041 1162
1042Provides rich asynchronous DNS resolver capabilities. 1163Provides rich asynchronous DNS resolver capabilities.
1043 1164
1165=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
1166
1167Implement event-based interfaces to the protocols of the same name (for
1168the curious, IGS is the International Go Server and FCP is the Freenet
1169Client Protocol).
1170
1044=item L<AnyEvent::HTTP> 1171=item L<AnyEvent::AIO>
1045 1172
1046A simple-to-use HTTP library that is capable of making a lot of concurrent 1173Truly asynchronous (as opposed to non-blocking) I/O, should be in the
1047HTTP requests. 1174toolbox of every event programmer. AnyEvent::AIO transparently fuses
1175L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
1176file I/O, and much more.
1177
1178=item L<AnyEvent::Filesys::Notify>
1179
1180AnyEvent is good for non-blocking stuff, but it can't detect file or
1181path changes (e.g. "watch this directory for new files", "watch this
1182file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
1183do just that in a portbale fashion, supporting inotify on GNU/Linux and
1184some weird, without doubt broken, stuff on OS X to monitor files. It can
1185fall back to blocking scans at regular intervals transparently on other
1186platforms, so it's about as portable as it gets.
1187
1188(I haven't used it myself, but I haven't heard anybody complaining about
1189it yet).
1190
1191=item L<AnyEvent::DBI>
1192
1193Executes L<DBI> requests asynchronously in a proxy process for you,
1194notifying you in an event-based way when the operation is finished.
1048 1195
1049=item L<AnyEvent::HTTPD> 1196=item L<AnyEvent::HTTPD>
1050 1197
1051Provides a simple web application server framework. 1198A simple embedded webserver.
1052 1199
1053=item L<AnyEvent::FastPing> 1200=item L<AnyEvent::FastPing>
1054 1201
1055The fastest ping in the west. 1202The fastest ping in the west.
1056 1203
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> 1204=item L<Coro>
1100 1205
1101Has special support for AnyEvent via L<Coro::AnyEvent>. 1206Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
1207to simply invert the flow control - don't call us, we will call you:
1208
1209 async {
1210 Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
1211 print "5 seconds later!\n";
1212
1213 Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
1214 my $line = <STDIN>; # works for ttys
1215
1216 AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
1217 my ($body, $hdr) = Coro::rouse_wait;
1218 };
1102 1219
1103=back 1220=back
1104 1221
1105=cut 1222=cut
1106 1223
1107package AnyEvent; 1224package AnyEvent;
1108 1225
1109# basically a tuned-down version of common::sense 1226# basically a tuned-down version of common::sense
1110sub common_sense { 1227sub common_sense {
1111 # from common:.sense 1.0 1228 # from common:.sense 3.4
1112 ${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03"; 1229 ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1113 # use strict vars subs 1230 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1114 $^H |= 0x00000600; 1231 $^H |= 0x00000600;
1115} 1232}
1116 1233
1117BEGIN { AnyEvent::common_sense } 1234BEGIN { AnyEvent::common_sense }
1118 1235
1119use Carp (); 1236use Carp ();
1120 1237
1121our $VERSION = '5.112'; 1238our $VERSION = '6.02';
1122our $MODEL; 1239our $MODEL;
1123 1240
1124our $AUTOLOAD;
1125our @ISA; 1241our @ISA;
1126 1242
1127our @REGISTRY; 1243our @REGISTRY;
1128 1244
1129our $WIN32;
1130
1131our $VERBOSE; 1245our $VERBOSE;
1132 1246
1133BEGIN { 1247BEGIN {
1134 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1248 require "AnyEvent/constants.pl";
1249
1135 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1250 eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1136 1251
1137 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1252 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1138 if ${^TAINT}; 1253 if ${^TAINT};
1139 1254
1255 $ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
1256 for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1257
1258 @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
1259 if ${^TAINT};
1260
1140 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1261 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1141
1142} 1262}
1143 1263
1144our $MAX_SIGNAL_LATENCY = 10; 1264our $MAX_SIGNAL_LATENCY = 10;
1145 1265
1146our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1266our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
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) { # also catches non-numeric levels(!)
1312 require AnyEvent::Log;
1313 # AnyEvent::Log overwrites this function
1314 goto &log;
1315 }
1316
1317 0 # not logged
1318}
1319
1320if (length $ENV{PERL_ANYEVENT_LOG}) {
1321 require AnyEvent::Log; # AnyEvent::Log does the thing for us
1322}
1323
1155my @models = ( 1324our @models = (
1156 [EV:: => AnyEvent::Impl::EV:: , 1], 1325 [EV:: => AnyEvent::Impl::EV:: , 1],
1157 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], 1326 [AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1158 # everything below here will not (normally) be autoprobed 1327 # everything below here will not (normally) be autoprobed
1159 # as the pureperl backend should work everywhere 1328 # as the pure perl backend should work everywhere
1160 # and is usually faster 1329 # and is usually faster
1161 [Event:: => AnyEvent::Impl::Event::, 1], 1330 [Event:: => AnyEvent::Impl::Event::, 1],
1162 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers 1331 [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1163 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1332 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1164 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package 1333 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1165 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1334 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1166 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1335 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1167 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1336 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1168 [Wx:: => AnyEvent::Impl::POE::], 1337 [Wx:: => AnyEvent::Impl::POE::],
1169 [Prima:: => AnyEvent::Impl::POE::], 1338 [Prima:: => AnyEvent::Impl::POE::],
1170 # IO::Async is just too broken - we would need workarounds for its 1339 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1171 # byzantine signal and broken child handling, among others. 1340 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1172 # IO::Async is rather hard to detect, as it doesn't have any 1341 [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); 1342);
1179 1343
1180our %method = map +($_ => 1), 1344our @isa_hook;
1345
1346sub _isa_set {
1347 my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
1348
1349 @{"$pkg[$_-1]::ISA"} = $pkg[$_]
1350 for 1 .. $#pkg;
1351
1352 grep $_ && $_->[1], @isa_hook
1353 and AE::_reset ();
1354}
1355
1356# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
1357sub _isa_hook($$;$) {
1358 my ($i, $pkg, $reset_ae) = @_;
1359
1360 $isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
1361
1362 _isa_set;
1363}
1364
1365# all autoloaded methods reserve the complete glob, not just the method slot.
1366# due to bugs in perls method cache implementation.
1181 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1367our @methods = qw(io timer time now now_update signal child idle condvar);
1182 1368
1183our @post_detect;
1184
1185sub post_detect(&) { 1369sub detect() {
1186 my ($cb) = @_; 1370 return $MODEL if $MODEL; # some programs keep references to detect
1187 1371
1188 if ($MODEL) { 1372 local $!; # for good measure
1189 $cb->(); 1373 local $SIG{__DIE__}; # we use eval
1190 1374
1191 undef 1375 # free some memory
1376 *detect = sub () { $MODEL };
1377 # undef &func doesn't correctly update the method cache. grmbl.
1378 # so we delete the whole glob. grmbl.
1379 # otoh, perl doesn't let me undef an active usb, but it lets me free
1380 # a glob with an active sub. hrm. i hope it works, but perl is
1381 # usually buggy in this department. sigh.
1382 delete @{"AnyEvent::"}{@methods};
1383 undef @methods;
1384
1385 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
1386 my $model = $1;
1387 $model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
1388 if (eval "require $model") {
1389 AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
1390 $MODEL = $model;
1192 } else { 1391 } else {
1193 push @post_detect, $cb; 1392 AnyEvent::log 5 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1194 1393 }
1195 defined wantarray
1196 ? bless \$cb, "AnyEvent::Util::postdetect"
1197 : ()
1198 } 1394 }
1199}
1200 1395
1201sub AnyEvent::Util::postdetect::DESTROY { 1396 # check for already loaded models
1202 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1203}
1204
1205sub detect() {
1206 unless ($MODEL) { 1397 unless ($MODEL) {
1207 local $SIG{__DIE__}; 1398 for (@REGISTRY, @models) {
1208 1399 my ($package, $model) = @$_;
1209 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1400 if (${"$package\::VERSION"} > 0) {
1210 my $model = "AnyEvent::Impl::$1";
1211 if (eval "require $model") { 1401 if (eval "require $model") {
1402 AnyEvent::log 7 => "autodetected model '$model', using it.";
1212 $MODEL = $model; 1403 $MODEL = $model;
1213 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; 1404 last;
1214 } else { 1405 }
1215 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1216 } 1406 }
1217 } 1407 }
1218 1408
1219 # check for already loaded models
1220 unless ($MODEL) { 1409 unless ($MODEL) {
1410 # try to autoload a model
1221 for (@REGISTRY, @models) { 1411 for (@REGISTRY, @models) {
1222 my ($package, $model) = @$_; 1412 my ($package, $model, $autoload) = @$_;
1413 if (
1414 $autoload
1415 and eval "require $package"
1223 if (${"$package\::VERSION"} > 0) { 1416 and ${"$package\::VERSION"} > 0
1224 if (eval "require $model") { 1417 and eval "require $model"
1418 ) {
1419 AnyEvent::log 7 => "autoloaded model '$model', using it.";
1225 $MODEL = $model; 1420 $MODEL = $model;
1226 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1227 last; 1421 last;
1228 }
1229 } 1422 }
1230 } 1423 }
1231 1424
1232 unless ($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 1425 $MODEL
1249 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; 1426 or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1250 }
1251 } 1427 }
1252
1253 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1254
1255 unshift @ISA, $MODEL;
1256
1257 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1258
1259 (shift @post_detect)->() while @post_detect;
1260 } 1428 }
1261 1429
1430 # free memory only needed for probing
1431 undef @models;
1432 undef @REGISTRY;
1433
1434 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1435
1436 # now nuke some methods that are overridden by the backend.
1437 # SUPER usage is not allowed in these.
1438 for (qw(time signal child idle)) {
1439 undef &{"AnyEvent::Base::$_"}
1440 if defined &{"$MODEL\::$_"};
1441 }
1442
1443 _isa_set;
1444
1445 # we're officially open!
1446
1447 if ($ENV{PERL_ANYEVENT_STRICT}) {
1448 require AnyEvent::Strict;
1449 }
1450
1451 if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
1452 require AnyEvent::Debug;
1453 AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
1454 }
1455
1456 if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
1457 require AnyEvent::Socket;
1458 require AnyEvent::Debug;
1459
1460 my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
1461 $shell =~ s/\$\$/$$/g;
1462
1463 my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
1464 $AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
1465 }
1466
1467 # now the anyevent environment is set up as the user told us to, so
1468 # call the actual user code - post detects
1469
1470 (shift @post_detect)->() while @post_detect;
1471 undef @post_detect;
1472
1473 *post_detect = sub(&) {
1474 shift->();
1475
1476 undef
1477 };
1478
1262 $MODEL 1479 $MODEL
1263} 1480}
1264 1481
1265sub AUTOLOAD { 1482for my $name (@methods) {
1266 (my $func = $AUTOLOAD) =~ s/.*://; 1483 *$name = sub {
1267 1484 detect;
1268 $method{$func} 1485 # we use goto because
1269 or Carp::croak "$func: not a valid method for AnyEvent objects"; 1486 # a) it makes the thunk more transparent
1270 1487 # b) it allows us to delete the thunk later
1271 detect unless $MODEL; 1488 goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1272 1489 };
1273 my $class = shift;
1274 $class->$func (@_);
1275} 1490}
1276 1491
1277# utility function to dup a filehandle. this is used by many backends 1492# utility function to dup a filehandle. this is used by many backends
1278# to support binding more than one watcher per filehandle (they usually 1493# 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). 1494# allow only one watcher per fd, so we dup it to get a different one).
1293 1508
1294=head1 SIMPLIFIED AE API 1509=head1 SIMPLIFIED AE API
1295 1510
1296Starting with version 5.0, AnyEvent officially supports a second, much 1511Starting with version 5.0, AnyEvent officially supports a second, much
1297simpler, API that is designed to reduce the calling, typing and memory 1512simpler, API that is designed to reduce the calling, typing and memory
1298overhead. 1513overhead by using function call syntax and a fixed number of parameters.
1299 1514
1300See the L<AE> manpage for details. 1515See the L<AE> manpage for details.
1301 1516
1302=cut 1517=cut
1303 1518
1304package AE; 1519package AE;
1305 1520
1306our $VERSION = $AnyEvent::VERSION; 1521our $VERSION = $AnyEvent::VERSION;
1307 1522
1523sub _reset() {
1524 eval q{
1525 # fall back to the main API by default - backends and AnyEvent::Base
1526 # implementations can overwrite these.
1527
1308sub io($$$) { 1528 sub io($$$) {
1309 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) 1529 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1310} 1530 }
1311 1531
1312sub timer($$$) { 1532 sub timer($$$) {
1313 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]) 1533 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1314} 1534 }
1315 1535
1316sub signal($$) { 1536 sub signal($$) {
1317 AnyEvent->signal (signal => $_[0], cb => $_[1]) 1537 AnyEvent->signal (signal => $_[0], cb => $_[1])
1318} 1538 }
1319 1539
1320sub child($$) { 1540 sub child($$) {
1321 AnyEvent->child (pid => $_[0], cb => $_[1]) 1541 AnyEvent->child (pid => $_[0], cb => $_[1])
1322} 1542 }
1323 1543
1324sub idle($) { 1544 sub idle($) {
1325 AnyEvent->idle (cb => $_[0]) 1545 AnyEvent->idle (cb => $_[0]);
1326} 1546 }
1327 1547
1328sub cv(;&) { 1548 sub cv(;&) {
1329 AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) 1549 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1330} 1550 }
1331 1551
1332sub now() { 1552 sub now() {
1333 AnyEvent->now 1553 AnyEvent->now
1334} 1554 }
1335 1555
1336sub now_update() { 1556 sub now_update() {
1337 AnyEvent->now_update 1557 AnyEvent->now_update
1338} 1558 }
1339 1559
1340sub time() { 1560 sub time() {
1341 AnyEvent->time 1561 AnyEvent->time
1562 }
1563
1564 *postpone = \&AnyEvent::postpone;
1565 *log = \&AnyEvent::log;
1566 };
1567 die if $@;
1342} 1568}
1569
1570BEGIN { _reset }
1343 1571
1344package AnyEvent::Base; 1572package AnyEvent::Base;
1345 1573
1346# default implementations for many methods 1574# default implementations for many methods
1347 1575
1348sub _time() { 1576sub time {
1577 eval q{ # poor man's autoloading {}
1349 # probe for availability of Time::HiRes 1578 # probe for availability of Time::HiRes
1350 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1579 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1351 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1580 *time = sub { Time::HiRes::time () };
1352 *_time = \&Time::HiRes::time; 1581 *AE::time = \& Time::HiRes::time ;
1582 *now = \&time;
1583 AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1353 # if (eval "use POSIX (); (POSIX::times())... 1584 # if (eval "use POSIX (); (POSIX::times())...
1354 } else { 1585 } else {
1586 *time = sub { CORE::time };
1587 *AE::time = sub (){ CORE::time };
1588 *now = \&time;
1355 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; 1589 AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
1356 *_time = sub { time }; # epic fail 1590 }
1357 } 1591 };
1592 die if $@;
1358 1593
1359 &_time 1594 &time
1360} 1595}
1361 1596
1362sub time { _time } 1597*now = \&time;
1363sub now { _time }
1364sub now_update { } 1598sub now_update { }
1365 1599
1600sub _poll {
1601 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
1602}
1603
1366# default implementation for ->condvar 1604# default implementation for ->condvar
1605# in fact, the default should not be overwritten
1367 1606
1368sub condvar { 1607sub condvar {
1608 eval q{ # poor man's autoloading {}
1609 *condvar = sub {
1369 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1610 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1611 };
1612
1613 *AE::cv = sub (;&) {
1614 bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
1615 };
1616 };
1617 die if $@;
1618
1619 &condvar
1370} 1620}
1371 1621
1372# default implementation for ->signal 1622# default implementation for ->signal
1373 1623
1374our $HAVE_ASYNC_INTERRUPT; 1624our $HAVE_ASYNC_INTERRUPT;
1383 1633
1384our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1634our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1385our (%SIG_ASY, %SIG_ASY_W); 1635our (%SIG_ASY, %SIG_ASY_W);
1386our ($SIG_COUNT, $SIG_TW); 1636our ($SIG_COUNT, $SIG_TW);
1387 1637
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 1638# install a dummy wakeup watcher to reduce signal catching latency
1639# used by Impls
1402sub _sig_add() { 1640sub _sig_add() {
1403 unless ($SIG_COUNT++) { 1641 unless ($SIG_COUNT++) {
1404 # try to align timer on a full-second boundary, if possible 1642 # try to align timer on a full-second boundary, if possible
1405 my $NOW = AE::now; 1643 my $NOW = AE::now;
1406 1644
1416 undef $SIG_TW 1654 undef $SIG_TW
1417 unless --$SIG_COUNT; 1655 unless --$SIG_COUNT;
1418} 1656}
1419 1657
1420our $_sig_name_init; $_sig_name_init = sub { 1658our $_sig_name_init; $_sig_name_init = sub {
1421 eval q{ # poor man's autoloading 1659 eval q{ # poor man's autoloading {}
1422 undef $_sig_name_init; 1660 undef $_sig_name_init;
1423 1661
1424 if (_have_async_interrupt) { 1662 if (_have_async_interrupt) {
1425 *sig2num = \&Async::Interrupt::sig2num; 1663 *sig2num = \&Async::Interrupt::sig2num;
1426 *sig2name = \&Async::Interrupt::sig2name; 1664 *sig2name = \&Async::Interrupt::sig2name;
1450 1688
1451sub signal { 1689sub signal {
1452 eval q{ # poor man's autoloading {} 1690 eval q{ # poor man's autoloading {}
1453 # probe for availability of Async::Interrupt 1691 # probe for availability of Async::Interrupt
1454 if (_have_async_interrupt) { 1692 if (_have_async_interrupt) {
1455 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8; 1693 AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
1456 1694
1457 $SIGPIPE_R = new Async::Interrupt::EventPipe; 1695 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1458 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec; 1696 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1459 1697
1460 } else { 1698 } else {
1461 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8; 1699 AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
1462
1463 require Fcntl;
1464 1700
1465 if (AnyEvent::WIN32) { 1701 if (AnyEvent::WIN32) {
1466 require AnyEvent::Util; 1702 require AnyEvent::Util;
1467 1703
1468 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); 1704 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1469 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R; 1705 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1470 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case 1706 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1471 } else { 1707 } else {
1472 pipe $SIGPIPE_R, $SIGPIPE_W; 1708 pipe $SIGPIPE_R, $SIGPIPE_W;
1473 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1709 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 1710 fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1475 1711
1476 # not strictly required, as $^F is normally 2, but let's make sure... 1712 # not strictly required, as $^F is normally 2, but let's make sure...
1477 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1713 fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1478 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; 1714 fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1479 } 1715 }
1480 1716
1481 $SIGPIPE_R 1717 $SIGPIPE_R
1482 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1718 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1483 1719
1484 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec; 1720 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1485 } 1721 }
1486 1722
1487 *signal = sub { 1723 *signal = $HAVE_ASYNC_INTERRUPT
1724 ? sub {
1488 my (undef, %arg) = @_; 1725 my (undef, %arg) = @_;
1489 1726
1490 my $signal = uc $arg{signal}
1491 or Carp::croak "required option 'signal' is missing";
1492
1493 if ($HAVE_ASYNC_INTERRUPT) {
1494 # async::interrupt 1727 # async::interrupt
1495
1496 $signal = sig2num $signal; 1728 my $signal = sig2num $arg{signal};
1497 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1729 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1498 1730
1499 $SIG_ASY{$signal} ||= new Async::Interrupt 1731 $SIG_ASY{$signal} ||= new Async::Interrupt
1500 cb => sub { undef $SIG_EV{$signal} }, 1732 cb => sub { undef $SIG_EV{$signal} },
1501 signal => $signal, 1733 signal => $signal,
1502 pipe => [$SIGPIPE_R->filenos], 1734 pipe => [$SIGPIPE_R->filenos],
1503 pipe_autodrain => 0, 1735 pipe_autodrain => 0,
1504 ; 1736 ;
1505 1737
1506 } else { 1738 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1739 }
1740 : sub {
1741 my (undef, %arg) = @_;
1742
1507 # pure perl 1743 # pure perl
1508
1509 # AE::Util has been loaded in signal
1510 $signal = sig2name $signal; 1744 my $signal = sig2name $arg{signal};
1511 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1745 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1512 1746
1513 $SIG{$signal} ||= sub { 1747 $SIG{$signal} ||= sub {
1514 local $!; 1748 local $!;
1515 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1749 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1516 undef $SIG_EV{$signal}; 1750 undef $SIG_EV{$signal};
1517 }; 1751 };
1518 1752
1519 # can't do signal processing without introducing races in pure perl, 1753 # can't do signal processing without introducing races in pure perl,
1520 # so limit the signal latency. 1754 # so limit the signal latency.
1521 _sig_add; 1755 _sig_add;
1522 }
1523 1756
1524 bless [$signal, $arg{cb}], "AnyEvent::Base::signal" 1757 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1758 }
1525 }; 1759 ;
1526 1760
1527 *AnyEvent::Base::signal::DESTROY = sub { 1761 *AnyEvent::Base::signal::DESTROY = sub {
1528 my ($signal, $cb) = @{$_[0]}; 1762 my ($signal, $cb) = @{$_[0]};
1529 1763
1530 _sig_del; 1764 _sig_del;
1537 # print weird messages, or just unconditionally exit 1771 # print weird messages, or just unconditionally exit
1538 # instead of getting the default action. 1772 # instead of getting the default action.
1539 undef $SIG{$signal} 1773 undef $SIG{$signal}
1540 unless keys %{ $SIG_CB{$signal} }; 1774 unless keys %{ $SIG_CB{$signal} };
1541 }; 1775 };
1776
1777 *_signal_exec = sub {
1778 $HAVE_ASYNC_INTERRUPT
1779 ? $SIGPIPE_R->drain
1780 : sysread $SIGPIPE_R, (my $dummy), 9;
1781
1782 while (%SIG_EV) {
1783 for (keys %SIG_EV) {
1784 delete $SIG_EV{$_};
1785 &$_ for values %{ $SIG_CB{$_} || {} };
1786 }
1787 }
1788 };
1542 }; 1789 };
1543 die if $@; 1790 die if $@;
1791
1544 &signal 1792 &signal
1545} 1793}
1546 1794
1547# default implementation for ->child 1795# default implementation for ->child
1548 1796
1549our %PID_CB; 1797our %PID_CB;
1550our $CHLD_W; 1798our $CHLD_W;
1551our $CHLD_DELAY_W; 1799our $CHLD_DELAY_W;
1552our $WNOHANG;
1553 1800
1801# used by many Impl's
1554sub _emit_childstatus($$) { 1802sub _emit_childstatus($$) {
1555 my (undef, $rpid, $rstatus) = @_; 1803 my (undef, $rpid, $rstatus) = @_;
1556 1804
1557 $_->($rpid, $rstatus) 1805 $_->($rpid, $rstatus)
1558 for values %{ $PID_CB{$rpid} || {} }, 1806 for values %{ $PID_CB{$rpid} || {} },
1559 values %{ $PID_CB{0} || {} }; 1807 values %{ $PID_CB{0} || {} };
1560} 1808}
1561 1809
1562sub _sigchld {
1563 my $pid;
1564
1565 AnyEvent->_emit_childstatus ($pid, $?)
1566 while ($pid = waitpid -1, $WNOHANG) > 0;
1567}
1568
1569sub child { 1810sub child {
1811 eval q{ # poor man's autoloading {}
1812 *_sigchld = sub {
1813 my $pid;
1814
1815 AnyEvent->_emit_childstatus ($pid, $?)
1816 while ($pid = waitpid -1, WNOHANG) > 0;
1817 };
1818
1819 *child = sub {
1570 my (undef, %arg) = @_; 1820 my (undef, %arg) = @_;
1571 1821
1572 defined (my $pid = $arg{pid} + 0) 1822 my $pid = $arg{pid};
1573 or Carp::croak "required option 'pid' is missing"; 1823 my $cb = $arg{cb};
1574 1824
1575 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1825 $PID_CB{$pid}{$cb+0} = $cb;
1576 1826
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) { 1827 unless ($CHLD_W) {
1583 $CHLD_W = AE::signal CHLD => \&_sigchld; 1828 $CHLD_W = AE::signal CHLD => \&_sigchld;
1584 # child could be a zombie already, so make at least one round 1829 # child could be a zombie already, so make at least one round
1585 &_sigchld; 1830 &_sigchld;
1586 } 1831 }
1587 1832
1588 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1833 bless [$pid, $cb+0], "AnyEvent::Base::child"
1589} 1834 };
1590 1835
1591sub AnyEvent::Base::child::DESTROY { 1836 *AnyEvent::Base::child::DESTROY = sub {
1592 my ($pid, $cb) = @{$_[0]}; 1837 my ($pid, $icb) = @{$_[0]};
1593 1838
1594 delete $PID_CB{$pid}{$cb}; 1839 delete $PID_CB{$pid}{$icb};
1595 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1840 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1596 1841
1597 undef $CHLD_W unless keys %PID_CB; 1842 undef $CHLD_W unless keys %PID_CB;
1843 };
1844 };
1845 die if $@;
1846
1847 &child
1598} 1848}
1599 1849
1600# idle emulation is done by simply using a timer, regardless 1850# idle emulation is done by simply using a timer, regardless
1601# of whether the process is idle or not, and not letting 1851# of whether the process is idle or not, and not letting
1602# the callback use more than 50% of the time. 1852# the callback use more than 50% of the time.
1603sub idle { 1853sub idle {
1854 eval q{ # poor man's autoloading {}
1855 *idle = sub {
1604 my (undef, %arg) = @_; 1856 my (undef, %arg) = @_;
1605 1857
1606 my ($cb, $w, $rcb) = $arg{cb}; 1858 my ($cb, $w, $rcb) = $arg{cb};
1607 1859
1608 $rcb = sub { 1860 $rcb = sub {
1609 if ($cb) { 1861 if ($cb) {
1610 $w = _time; 1862 $w = AE::time;
1611 &$cb; 1863 &$cb;
1612 $w = _time - $w; 1864 $w = AE::time - $w;
1613 1865
1614 # never use more then 50% of the time for the idle watcher, 1866 # never use more then 50% of the time for the idle watcher,
1615 # within some limits 1867 # within some limits
1616 $w = 0.0001 if $w < 0.0001; 1868 $w = 0.0001 if $w < 0.0001;
1617 $w = 5 if $w > 5; 1869 $w = 5 if $w > 5;
1618 1870
1619 $w = AE::timer $w, 0, $rcb; 1871 $w = AE::timer $w, 0, $rcb;
1620 } else { 1872 } else {
1621 # clean up... 1873 # clean up...
1622 undef $w; 1874 undef $w;
1623 undef $rcb; 1875 undef $rcb;
1876 }
1877 };
1878
1879 $w = AE::timer 0.05, 0, $rcb;
1880
1881 bless \\$cb, "AnyEvent::Base::idle"
1624 } 1882 };
1883
1884 *AnyEvent::Base::idle::DESTROY = sub {
1885 undef $${$_[0]};
1886 };
1625 }; 1887 };
1888 die if $@;
1626 1889
1627 $w = AE::timer 0.05, 0, $rcb; 1890 &idle
1628
1629 bless \\$cb, "AnyEvent::Base::idle"
1630}
1631
1632sub AnyEvent::Base::idle::DESTROY {
1633 undef $${$_[0]};
1634} 1891}
1635 1892
1636package AnyEvent::CondVar; 1893package AnyEvent::CondVar;
1637 1894
1638our @ISA = AnyEvent::CondVar::Base::; 1895our @ISA = AnyEvent::CondVar::Base::;
1896
1897# only to be used for subclassing
1898sub new {
1899 my $class = shift;
1900 bless AnyEvent->condvar (@_), $class
1901}
1639 1902
1640package AnyEvent::CondVar::Base; 1903package AnyEvent::CondVar::Base;
1641 1904
1642#use overload 1905#use overload
1643# '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1906# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1653 1916
1654sub _send { 1917sub _send {
1655 # nop 1918 # nop
1656} 1919}
1657 1920
1921sub _wait {
1922 AnyEvent->_poll until $_[0]{_ae_sent};
1923}
1924
1658sub send { 1925sub send {
1659 my $cv = shift; 1926 my $cv = shift;
1660 $cv->{_ae_sent} = [@_]; 1927 $cv->{_ae_sent} = [@_];
1661 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; 1928 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1662 $cv->_send; 1929 $cv->_send;
1669 1936
1670sub ready { 1937sub ready {
1671 $_[0]{_ae_sent} 1938 $_[0]{_ae_sent}
1672} 1939}
1673 1940
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 { 1941sub recv {
1942 unless ($_[0]{_ae_sent}) {
1943 $WAITING
1944 and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
1945
1946 local $WAITING = 1;
1684 $_[0]->_wait; 1947 $_[0]->_wait;
1948 }
1685 1949
1686 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1950 $_[0]{_ae_croak}
1687 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1951 and Carp::croak $_[0]{_ae_croak};
1952
1953 wantarray
1954 ? @{ $_[0]{_ae_sent} }
1955 : $_[0]{_ae_sent}[0]
1688} 1956}
1689 1957
1690sub cb { 1958sub cb {
1691 my $cv = shift; 1959 my $cv = shift;
1692 1960
1708 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; 1976 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1709} 1977}
1710 1978
1711# undocumented/compatibility with pre-3.4 1979# undocumented/compatibility with pre-3.4
1712*broadcast = \&send; 1980*broadcast = \&send;
1713*wait = \&_wait; 1981*wait = \&recv;
1714 1982
1715=head1 ERROR AND EXCEPTION HANDLING 1983=head1 ERROR AND EXCEPTION HANDLING
1716 1984
1717In general, AnyEvent does not do any error handling - it relies on the 1985In 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 1986caller to do that if required. The L<AnyEvent::Strict> module (see also
1730$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and 1998$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1731so on. 1999so on.
1732 2000
1733=head1 ENVIRONMENT VARIABLES 2001=head1 ENVIRONMENT VARIABLES
1734 2002
1735The following environment variables are used by this module or its 2003AnyEvent supports a number of environment variables that tune the
1736submodules. 2004runtime behaviour. They are usually evaluated when AnyEvent is
2005loaded, initialised, or a submodule that uses them is loaded. Many of
2006them also cause AnyEvent to load additional modules - for example,
2007C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
2008loaded.
1737 2009
1738Note that AnyEvent will remove I<all> environment variables starting with 2010All the environment variables documented here start with
1739C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is 2011C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1740enabled. 2012namespace. Other modules are encouraged (but by no means required) to use
2013C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
2014namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
2015be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
2016variables starting with C<AE_>, see below).
2017
2018All variables can also be set via the C<AE_> prefix, that is, instead
2019of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
2020case there is a clash btween anyevent and another program that uses
2021C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
2022variable to the empty string, as those variables take precedence.
2023
2024When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
2025to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
2026exists. If taint mode is on, then AnyEvent will remove I<all> environment
2027variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
2028with C<undef> or the empty string, if the corresaponding C<AE_> variable
2029is set).
2030
2031The exact algorithm is currently:
2032
2033 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
2034 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
2035 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
2036
2037This ensures that child processes will not see the C<AE_> variables.
2038
2039The following environment variables are currently known to AnyEvent:
1741 2040
1742=over 4 2041=over 4
1743 2042
1744=item C<PERL_ANYEVENT_VERBOSE> 2043=item C<PERL_ANYEVENT_VERBOSE>
1745 2044
1746By default, AnyEvent will be completely silent except in fatal 2045By default, AnyEvent will be completely silent except in fatal
1747conditions. You can set this environment variable to make AnyEvent more 2046conditions. You can set this environment variable to make AnyEvent more
1748talkative. 2047talkative. If you want to do more than just set the global logging level
2048you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
2049complex specifications.
1749 2050
1750When set to C<1> or higher, causes AnyEvent to warn about unexpected 2051When set to C<5> or higher (warn), causes AnyEvent to warn about unexpected
1751conditions, such as not being able to load the event model specified by 2052conditions, such as not being able to load the event model specified by
1752C<PERL_ANYEVENT_MODEL>. 2053C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
2054is the minimum recommended level.
1753 2055
1754When set to C<2> or higher, cause AnyEvent to report to STDERR which event 2056When set to C<7> or higher (info), cause AnyEvent to report which event model it
1755model it chooses. 2057chooses.
1756 2058
1757When set to C<8> or higher, then AnyEvent will report extra information on 2059When set to C<8> or higher (debug), then AnyEvent will report extra information on
1758which optional modules it loads and how it implements certain features. 2060which optional modules it loads and how it implements certain features.
2061
2062=item C<PERL_ANYEVENT_LOG>
2063
2064Accepts rather complex logging specifications. For example, you could log
2065all C<debug> messages of some module to stderr, warnings and above to
2066stderr, and errors and above to syslog, with:
2067
2068 PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
2069
2070For the rather extensive details, see L<AnyEvent::Log>.
2071
2072This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
2073so will take effect even before AnyEvent has initialised itself.
2074
2075Note that specifying this environment variable causes the L<AnyEvent::Log>
2076module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
2077using the latter saves a few hundred kB of memory until the first message
2078is being logged.
1759 2079
1760=item C<PERL_ANYEVENT_STRICT> 2080=item C<PERL_ANYEVENT_STRICT>
1761 2081
1762AnyEvent does not do much argument checking by default, as thorough 2082AnyEvent does not do much argument checking by default, as thorough
1763argument checking is very costly. Setting this variable to a true value 2083argument checking is very costly. Setting this variable to a true value
1765check the arguments passed to most method calls. If it finds any problems, 2085check the arguments passed to most method calls. If it finds any problems,
1766it will croak. 2086it will croak.
1767 2087
1768In other words, enables "strict" mode. 2088In other words, enables "strict" mode.
1769 2089
1770Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense> 2090Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1771>>, it is definitely recommended to keep it off in production. Keeping 2091>>, it is definitely recommended to keep it off in production. Keeping
1772C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs 2092C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1773can be very useful, however. 2093can be very useful, however.
1774 2094
2095=item C<PERL_ANYEVENT_DEBUG_SHELL>
2096
2097If this env variable is set, then its contents will be interpreted by
2098C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
2099C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
2100that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
2101
2102This happens when the first watcher is created.
2103
2104For example, to bind a debug shell on a unix domain socket in
2105F<< /tmp/debug<pid>.sock >>, you could use this:
2106
2107 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
2108
2109Note that creating sockets in F</tmp> is very unsafe on multiuser
2110systems.
2111
2112=item C<PERL_ANYEVENT_DEBUG_WRAP>
2113
2114Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
2115debugging purposes. See C<AnyEvent::Debug::wrap> for details.
2116
1775=item C<PERL_ANYEVENT_MODEL> 2117=item C<PERL_ANYEVENT_MODEL>
1776 2118
1777This can be used to specify the event model to be used by AnyEvent, before 2119This 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 2120auto detection and -probing kicks in.
1779entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 2121
2122It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
2123or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1780and the resulting module name is loaded and if the load was successful, 2124resulting 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 2125event model backend. If it fails to load then AnyEvent will proceed with
1782auto detection and -probing. 2126auto detection and -probing.
1783 2127
1784This functionality might change in future versions. 2128If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
2129nothing gets prepended and the module name is used as-is (hint: C<::> at
2130the end of a string designates a module name and quotes it appropriately).
1785 2131
1786For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 2132For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1787could start your program like this: 2133could start your program like this:
1788 2134
1789 PERL_ANYEVENT_MODEL=Perl perl ... 2135 PERL_ANYEVENT_MODEL=Perl perl ...
1790 2136
1791=item C<PERL_ANYEVENT_PROTOCOLS> 2137=item C<PERL_ANYEVENT_PROTOCOLS>
1807but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 2153but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1808- only support IPv4, never try to resolve or contact IPv6 2154- only support IPv4, never try to resolve or contact IPv6
1809addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 2155addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1810IPv6, but prefer IPv6 over IPv4. 2156IPv6, but prefer IPv6 over IPv4.
1811 2157
2158=item C<PERL_ANYEVENT_HOSTS>
2159
2160This variable, if specified, overrides the F</etc/hosts> file used by
2161L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
2162from that file instead.
2163
1812=item C<PERL_ANYEVENT_EDNS0> 2164=item C<PERL_ANYEVENT_EDNS0>
1813 2165
1814Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension 2166Used 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 2167DNS. This extension is generally useful to reduce DNS traffic, especially
1816some (broken) firewalls drop such DNS packets, which is why it is off by 2168when DNSSEC is involved, but some (broken) firewalls drop such DNS
1817default. 2169packets, which is why it is off by default.
1818 2170
1819Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 2171Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1820EDNS0 in its DNS requests. 2172EDNS0 in its DNS requests.
1821 2173
1822=item C<PERL_ANYEVENT_MAX_FORKS> 2174=item C<PERL_ANYEVENT_MAX_FORKS>
1830resolver - this is the maximum number of parallel DNS requests that are 2182resolver - this is the maximum number of parallel DNS requests that are
1831sent to the DNS server. 2183sent to the DNS server.
1832 2184
1833=item C<PERL_ANYEVENT_RESOLV_CONF> 2185=item C<PERL_ANYEVENT_RESOLV_CONF>
1834 2186
1835The file to use instead of F</etc/resolv.conf> (or OS-specific 2187The 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 2188F</etc/resolv.conf> (or the OS-specific configuration) in the default
1837default config will be used. 2189resolver, or the empty string to select the default configuration.
1838 2190
1839=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. 2191=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1840 2192
1841When neither C<ca_file> nor C<ca_path> was specified during 2193When neither C<ca_file> nor C<ca_path> was specified during
1842L<AnyEvent::TLS> context creation, and either of these environment 2194L<AnyEvent::TLS> context creation, and either of these environment
1843variables exist, they will be used to specify CA certificate locations 2195variables are nonempty, they will be used to specify CA certificate
1844instead of a system-dependent default. 2196locations instead of a system-dependent default.
1845 2197
1846=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT> 2198=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1847 2199
1848When these are set to C<1>, then the respective modules are not 2200When these are set to C<1>, then the respective modules are not
1849loaded. Mostly good for testing AnyEvent itself. 2201loaded. Mostly good for testing AnyEvent itself.
1997 2349
1998The actual code goes further and collects all errors (C<die>s, exceptions) 2350The actual code goes further and collects all errors (C<die>s, exceptions)
1999that occurred during request processing. The C<result> method detects 2351that occurred during request processing. The C<result> method detects
2000whether an exception as thrown (it is stored inside the $txn object) 2352whether an exception as thrown (it is stored inside the $txn object)
2001and just throws the exception, which means connection errors and other 2353and just throws the exception, which means connection errors and other
2002problems get reported tot he code that tries to use the result, not in a 2354problems get reported to the code that tries to use the result, not in a
2003random callback. 2355random callback.
2004 2356
2005All of this enables the following usage styles: 2357All of this enables the following usage styles:
2006 2358
20071. Blocking: 23591. Blocking:
2181(even when used without AnyEvent), but most event loops have acceptable 2533(even when used without AnyEvent), but most event loops have acceptable
2182performance with or without AnyEvent. 2534performance with or without AnyEvent.
2183 2535
2184=item * The overhead AnyEvent adds is usually much smaller than the overhead of 2536=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2185the actual event loop, only with extremely fast event loops such as EV 2537the actual event loop, only with extremely fast event loops such as EV
2186adds AnyEvent significant overhead. 2538does AnyEvent add significant overhead.
2187 2539
2188=item * You should avoid POE like the plague if you want performance or 2540=item * You should avoid POE like the plague if you want performance or
2189reasonable memory usage. 2541reasonable memory usage.
2190 2542
2191=back 2543=back
2421 unless defined $SIG{PIPE}; 2773 unless defined $SIG{PIPE};
2422 2774
2423=head1 RECOMMENDED/OPTIONAL MODULES 2775=head1 RECOMMENDED/OPTIONAL MODULES
2424 2776
2425One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and 2777One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2426it's built-in modules) are required to use it. 2778its built-in modules) are required to use it.
2427 2779
2428That does not mean that AnyEvent won't take advantage of some additional 2780That does not mean that AnyEvent won't take advantage of some additional
2429modules if they are installed. 2781modules if they are installed.
2430 2782
2431This section epxlains which additional modules will be used, and how they 2783This section explains which additional modules will be used, and how they
2432affect AnyEvent's operetion. 2784affect AnyEvent's operation.
2433 2785
2434=over 4 2786=over 4
2435 2787
2436=item L<Async::Interrupt> 2788=item L<Async::Interrupt>
2437 2789
2442catch the signals) with some delay (default is 10 seconds, look for 2794catch the signals) with some delay (default is 10 seconds, look for
2443C<$AnyEvent::MAX_SIGNAL_LATENCY>). 2795C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2444 2796
2445If this module is available, then it will be used to implement signal 2797If this module is available, then it will be used to implement signal
2446catching, which means that signals will not be delayed, and the event loop 2798catching, which means that signals will not be delayed, and the event loop
2447will not be interrupted regularly, which is more efficient (And good for 2799will not be interrupted regularly, which is more efficient (and good for
2448battery life on laptops). 2800battery life on laptops).
2449 2801
2450This affects not just the pure-perl event loop, but also other event loops 2802This affects not just the pure-perl event loop, but also other event loops
2451that have no signal handling on their own (e.g. Glib, Tk, Qt). 2803that have no signal handling on their own (e.g. Glib, Tk, Qt).
2452 2804
2464automatic timer adjustments even when no monotonic clock is available, 2816automatic timer adjustments even when no monotonic clock is available,
2465can take avdantage of advanced kernel interfaces such as C<epoll> and 2817can take avdantage of advanced kernel interfaces such as C<epoll> and
2466C<kqueue>, and is the fastest backend I<by far>. You can even embed 2818C<kqueue>, and is the fastest backend I<by far>. You can even embed
2467L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>). 2819L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2468 2820
2821If you only use backends that rely on another event loop (e.g. C<Tk>),
2822then this module will do nothing for you.
2823
2469=item L<Guard> 2824=item L<Guard>
2470 2825
2471The guard module, when used, will be used to implement 2826The guard module, when used, will be used to implement
2472C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a 2827C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2473lot less memory), but otherwise doesn't affect guard operation much. It is 2828lot less memory), but otherwise doesn't affect guard operation much. It is
2474purely used for performance. 2829purely used for performance.
2475 2830
2476=item L<JSON> and L<JSON::XS> 2831=item L<JSON> and L<JSON::XS>
2477 2832
2478This module is required when you want to read or write JSON data via 2833One of these modules is required when you want to read or write JSON data
2479L<AnyEvent::Handle>. It is also written in pure-perl, but can take 2834via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2480advantage of the ultra-high-speed L<JSON::XS> module when it is installed. 2835advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2481
2482In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2483installed.
2484 2836
2485=item L<Net::SSLeay> 2837=item L<Net::SSLeay>
2486 2838
2487Implementing TLS/SSL in Perl is certainly interesting, but not very 2839Implementing TLS/SSL in Perl is certainly interesting, but not very
2488worthwhile: If this module is installed, then L<AnyEvent::Handle> (with 2840worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2489the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL. 2841the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2490 2842
2491=item L<Time::HiRes> 2843=item L<Time::HiRes>
2492 2844
2493This module is part of perl since release 5.008. It will be used when the 2845This module is part of perl since release 5.008. It will be used when the
2494chosen event library does not come with a timing source on it's own. The 2846chosen event library does not come with a timing source of its own. The
2495pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to 2847pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2496try to use a monotonic clock for timing stability. 2848try to use a monotonic clock for timing stability.
2497 2849
2498=back 2850=back
2499 2851
2500 2852
2501=head1 FORK 2853=head1 FORK
2502 2854
2503Most event libraries are not fork-safe. The ones who are usually are 2855Most event libraries are not fork-safe. The ones who are usually are
2504because they rely on inefficient but fork-safe C<select> or C<poll> 2856because they rely on inefficient but fork-safe C<select> or C<poll> calls
2505calls. Only L<EV> is fully fork-aware. 2857- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2858are usually badly thought-out hacks that are incompatible with fork in
2859one way or another. Only L<EV> is fully fork-aware and ensures that you
2860continue event-processing in both parent and child (or both, if you know
2861what you are doing).
2862
2863This means that, in general, you cannot fork and do event processing in
2864the child if the event library was initialised before the fork (which
2865usually happens when the first AnyEvent watcher is created, or the library
2866is loaded).
2506 2867
2507If you have to fork, you must either do so I<before> creating your first 2868If you have to fork, you must either do so I<before> creating your first
2508watcher OR you must not use AnyEvent at all in the child OR you must do 2869watcher OR you must not use AnyEvent at all in the child OR you must do
2509something completely out of the scope of AnyEvent. 2870something completely out of the scope of AnyEvent.
2871
2872The problem of doing event processing in the parent I<and> the child
2873is much more complicated: even for backends that I<are> fork-aware or
2874fork-safe, their behaviour is not usually what you want: fork clones all
2875watchers, that means all timers, I/O watchers etc. are active in both
2876parent and child, which is almost never what you want. USing C<exec>
2877to start worker children from some kind of manage rprocess is usually
2878preferred, because it is much easier and cleaner, at the expense of having
2879to have another binary.
2510 2880
2511 2881
2512=head1 SECURITY CONSIDERATIONS 2882=head1 SECURITY CONSIDERATIONS
2513 2883
2514AnyEvent can be forced to load any event model via 2884AnyEvent can be forced to load any event model via
2544pronounced). 2914pronounced).
2545 2915
2546 2916
2547=head1 SEE ALSO 2917=head1 SEE ALSO
2548 2918
2549Utility functions: L<AnyEvent::Util>. 2919Tutorial/Introduction: L<AnyEvent::Intro>.
2550 2920
2551Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 2921FAQ: L<AnyEvent::FAQ>.
2552L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2922
2923Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
2924(simply logging).
2925
2926Development/Debugging: L<AnyEvent::Strict> (stricter checking),
2927L<AnyEvent::Debug> (interactive shell, watcher tracing).
2928
2929Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
2930L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
2931L<Qt>, L<POE>, L<FLTK>.
2553 2932
2554Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2933Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2555L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2934L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2556L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2935L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2557L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>. 2936L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
2937L<AnyEvent::Impl::FLTK>.
2558 2938
2559Non-blocking file handles, sockets, TCP clients and 2939Non-blocking handles, pipes, stream sockets, TCP clients and
2560servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 2940servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2561 2941
2562Asynchronous DNS: L<AnyEvent::DNS>. 2942Asynchronous DNS: L<AnyEvent::DNS>.
2563 2943
2564Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, 2944Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2565L<Coro::Event>,
2566 2945
2567Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>, 2946Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2568L<AnyEvent::HTTP>. 2947L<AnyEvent::HTTP>.
2569 2948
2570 2949
2571=head1 AUTHOR 2950=head1 AUTHOR
2572 2951

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