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1NAME 1NAME
2 AnyEvent - the DBI of event loop programming 2 AnyEvent - the DBI of event loop programming
3 3
4 EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, 4 EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async,
5 Qt and POE are various supported event loops/environments. 5 Qt, FLTK and POE are various supported event loops/environments.
6 6
7SYNOPSIS 7SYNOPSIS
8 use AnyEvent; 8 use AnyEvent;
9 9
10 # if you prefer function calls, look at the L<AE> manpage for 10 # if you prefer function calls, look at the AE manpage for
11 # an alternative API. 11 # an alternative API.
12 12
13 # file handle or descriptor readable 13 # file handle or descriptor readable
14 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); 14 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
15 15
16 # one-shot or repeating timers 16 # one-shot or repeating timers
17 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); 17 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
18 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... 18 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
19 19
20 print AnyEvent->now; # prints current event loop time 20 print AnyEvent->now; # prints current event loop time
21 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. 21 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
22 22
23 # POSIX signal 23 # POSIX signal
42 This manpage is mainly a reference manual. If you are interested in a 42 This manpage is mainly a reference manual. If you are interested in a
43 tutorial or some gentle introduction, have a look at the AnyEvent::Intro 43 tutorial or some gentle introduction, have a look at the AnyEvent::Intro
44 manpage. 44 manpage.
45 45
46SUPPORT 46SUPPORT
47 An FAQ document is available as AnyEvent::FAQ.
48
47 There is a mailinglist for discussing all things AnyEvent, and an IRC 49 There also is a mailinglist for discussing all things AnyEvent, and an
48 channel, too. 50 IRC channel, too.
49 51
50 See the AnyEvent project page at the Schmorpforge Ta-Sa Software 52 See the AnyEvent project page at the Schmorpforge Ta-Sa Software
51 Repository, at <http://anyevent.schmorp.de>, for more info. 53 Repository, at <http://anyevent.schmorp.de>, for more info.
52 54
53WHY YOU SHOULD USE THIS MODULE (OR NOT) 55WHY YOU SHOULD USE THIS MODULE (OR NOT)
71 module users into the same thing by forcing them to use the same event 73 module users into the same thing by forcing them to use the same event
72 model you use. 74 model you use.
73 75
74 For modules like POE or IO::Async (which is a total misnomer as it is 76 For modules like POE or IO::Async (which is a total misnomer as it is
75 actually doing all I/O *synchronously*...), using them in your module is 77 actually doing all I/O *synchronously*...), using them in your module is
76 like joining a cult: After you joined, you are dependent on them and you 78 like joining a cult: After you join, you are dependent on them and you
77 cannot use anything else, as they are simply incompatible to everything 79 cannot use anything else, as they are simply incompatible to everything
78 that isn't them. What's worse, all the potential users of your module 80 that isn't them. What's worse, all the potential users of your module
79 are *also* forced to use the same event loop you use. 81 are *also* forced to use the same event loop you use.
80 82
81 AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 83 AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
82 fine. AnyEvent + Tk works fine etc. etc. but none of these work together 84 fine. AnyEvent + Tk works fine etc. etc. but none of these work together
83 with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your 85 with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
84 module uses one of those, every user of your module has to use it, too. 86 uses one of those, every user of your module has to use it, too. But if
85 But if your module uses AnyEvent, it works transparently with all event 87 your module uses AnyEvent, it works transparently with all event models
86 models it supports (including stuff like IO::Async, as long as those use 88 it supports (including stuff like IO::Async, as long as those use one of
87 one of the supported event loops. It is trivial to add new event loops 89 the supported event loops. It is easy to add new event loops to
88 to AnyEvent, too, so it is future-proof). 90 AnyEvent, too, so it is future-proof).
89 91
90 In addition to being free of having to use *the one and only true event 92 In addition to being free of having to use *the one and only true event
91 model*, AnyEvent also is free of bloat and policy: with POE or similar 93 model*, AnyEvent also is free of bloat and policy: with POE or similar
92 modules, you get an enormous amount of code and strict rules you have to 94 modules, you get an enormous amount of code and strict rules you have to
93 follow. AnyEvent, on the other hand, is lean and up to the point, by 95 follow. AnyEvent, on the other hand, is lean and to the point, by only
94 only offering the functionality that is necessary, in as thin as a 96 offering the functionality that is necessary, in as thin as a wrapper as
95 wrapper as technically possible. 97 technically possible.
96 98
97 Of course, AnyEvent comes with a big (and fully optional!) toolbox of 99 Of course, AnyEvent comes with a big (and fully optional!) toolbox of
98 useful functionality, such as an asynchronous DNS resolver, 100% 100 useful functionality, such as an asynchronous DNS resolver, 100%
99 non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms 101 non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
100 such as Windows) and lots of real-world knowledge and workarounds for 102 such as Windows) and lots of real-world knowledge and workarounds for
103 Now, if you *do want* lots of policy (this can arguably be somewhat 105 Now, if you *do want* lots of policy (this can arguably be somewhat
104 useful) and you want to force your users to use the one and only event 106 useful) and you want to force your users to use the one and only event
105 model, you should *not* use this module. 107 model, you should *not* use this module.
106 108
107DESCRIPTION 109DESCRIPTION
108 AnyEvent provides an identical interface to multiple event loops. This 110 AnyEvent provides a uniform interface to various event loops. This
109 allows module authors to utilise an event loop without forcing module 111 allows module authors to use event loop functionality without forcing
110 users to use the same event loop (as only a single event loop can 112 module users to use a specific event loop implementation (since more
111 coexist peacefully at any one time). 113 than one event loop cannot coexist peacefully).
112 114
113 The interface itself is vaguely similar, but not identical to the Event 115 The interface itself is vaguely similar, but not identical to the Event
114 module. 116 module.
115 117
116 During the first call of any watcher-creation method, the module tries 118 During the first call of any watcher-creation method, the module tries
117 to detect the currently loaded event loop by probing whether one of the 119 to detect the currently loaded event loop by probing whether one of the
118 following modules is already loaded: EV, Event, Glib, 120 following modules is already loaded: EV, AnyEvent::Loop, Event, Glib,
119 AnyEvent::Impl::Perl, Tk, Event::Lib, Qt, POE. The first one found is 121 Tk, Event::Lib, Qt, POE. The first one found is used. If none are
120 used. If none are found, the module tries to load these modules 122 detected, the module tries to load the first four modules in the order
121 (excluding Tk, Event::Lib, Qt and POE as the pure perl adaptor should 123 given; but note that if EV is not available, the pure-perl
122 always succeed) in the order given. The first one that can be 124 AnyEvent::Loop should always work, so the other two are not normally
123 successfully loaded will be used. If, after this, still none could be 125 tried.
124 found, AnyEvent will fall back to a pure-perl event loop, which is not
125 very efficient, but should work everywhere.
126 126
127 Because AnyEvent first checks for modules that are already loaded, 127 Because AnyEvent first checks for modules that are already loaded,
128 loading an event model explicitly before first using AnyEvent will 128 loading an event model explicitly before first using AnyEvent will
129 likely make that model the default. For example: 129 likely make that model the default. For example:
130 130
132 use AnyEvent; 132 use AnyEvent;
133 133
134 # .. AnyEvent will likely default to Tk 134 # .. AnyEvent will likely default to Tk
135 135
136 The *likely* means that, if any module loads another event model and 136 The *likely* means that, if any module loads another event model and
137 starts using it, all bets are off. Maybe you should tell their authors 137 starts using it, all bets are off - this case should be very rare
138 to use AnyEvent so their modules work together with others seamlessly... 138 though, as very few modules hardcode event loops without announcing this
139 very loudly.
139 140
140 The pure-perl implementation of AnyEvent is called 141 The pure-perl implementation of AnyEvent is called "AnyEvent::Loop".
141 "AnyEvent::Impl::Perl". Like other event modules you can load it 142 Like other event modules you can load it explicitly and enjoy the high
142 explicitly and enjoy the high availability of that event loop :) 143 availability of that event loop :)
143 144
144WATCHERS 145WATCHERS
145 AnyEvent has the central concept of a *watcher*, which is an object that 146 AnyEvent has the central concept of a *watcher*, which is an object that
146 stores relevant data for each kind of event you are waiting for, such as 147 stores relevant data for each kind of event you are waiting for, such as
147 the callback to call, the file handle to watch, etc. 148 the callback to call, the file handle to watch, etc.
151 callback when the event occurs (of course, only when the event model is 152 callback when the event occurs (of course, only when the event model is
152 in control). 153 in control).
153 154
154 Note that callbacks must not permanently change global variables 155 Note that callbacks must not permanently change global variables
155 potentially in use by the event loop (such as $_ or $[) and that 156 potentially in use by the event loop (such as $_ or $[) and that
156 callbacks must not "die". The former is good programming practise in 157 callbacks must not "die". The former is good programming practice in
157 Perl and the latter stems from the fact that exception handling differs 158 Perl and the latter stems from the fact that exception handling differs
158 widely between event loops. 159 widely between event loops.
159 160
160 To disable the watcher you have to destroy it (e.g. by setting the 161 To disable a watcher you have to destroy it (e.g. by setting the
161 variable you store it in to "undef" or otherwise deleting all references 162 variable you store it in to "undef" or otherwise deleting all references
162 to it). 163 to it).
163 164
164 All watchers are created by calling a method on the "AnyEvent" class. 165 All watchers are created by calling a method on the "AnyEvent" class.
165 166
166 Many watchers either are used with "recursion" (repeating timers for 167 Many watchers either are used with "recursion" (repeating timers for
167 example), or need to refer to their watcher object in other ways. 168 example), or need to refer to their watcher object in other ways.
168 169
169 An any way to achieve that is this pattern: 170 One way to achieve that is this pattern:
170 171
171 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 172 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
172 # you can use $w here, for example to undef it 173 # you can use $w here, for example to undef it
173 undef $w; 174 undef $w;
174 }); 175 });
205 206
206 The I/O watcher might use the underlying file descriptor or a copy of 207 The I/O watcher might use the underlying file descriptor or a copy of
207 it. You must not close a file handle as long as any watcher is active on 208 it. You must not close a file handle as long as any watcher is active on
208 the underlying file descriptor. 209 the underlying file descriptor.
209 210
210 Some event loops issue spurious readyness notifications, so you should 211 Some event loops issue spurious readiness notifications, so you should
211 always use non-blocking calls when reading/writing from/to your file 212 always use non-blocking calls when reading/writing from/to your file
212 handles. 213 handles.
213 214
214 Example: wait for readability of STDIN, then read a line and disable the 215 Example: wait for readability of STDIN, then read a line and disable the
215 watcher. 216 watcher.
238 239
239 Although the callback might get passed parameters, their value and 240 Although the callback might get passed parameters, their value and
240 presence is undefined and you cannot rely on them. Portable AnyEvent 241 presence is undefined and you cannot rely on them. Portable AnyEvent
241 callbacks cannot use arguments passed to time watcher callbacks. 242 callbacks cannot use arguments passed to time watcher callbacks.
242 243
243 The callback will normally be invoked once only. If you specify another 244 The callback will normally be invoked only once. If you specify another
244 parameter, "interval", as a strictly positive number (> 0), then the 245 parameter, "interval", as a strictly positive number (> 0), then the
245 callback will be invoked regularly at that interval (in fractional 246 callback will be invoked regularly at that interval (in fractional
246 seconds) after the first invocation. If "interval" is specified with a 247 seconds) after the first invocation. If "interval" is specified with a
247 false value, then it is treated as if it were missing. 248 false value, then it is treated as if it were not specified at all.
248 249
249 The callback will be rescheduled before invoking the callback, but no 250 The callback will be rescheduled before invoking the callback, but no
250 attempt is done to avoid timer drift in most backends, so the interval 251 attempt is made to avoid timer drift in most backends, so the interval
251 is only approximate. 252 is only approximate.
252 253
253 Example: fire an event after 7.7 seconds. 254 Example: fire an event after 7.7 seconds.
254 255
255 my $w = AnyEvent->timer (after => 7.7, cb => sub { 256 my $w = AnyEvent->timer (after => 7.7, cb => sub {
272 273
273 While most event loops expect timers to specified in a relative way, 274 While most event loops expect timers to specified in a relative way,
274 they use absolute time internally. This makes a difference when your 275 they use absolute time internally. This makes a difference when your
275 clock "jumps", for example, when ntp decides to set your clock backwards 276 clock "jumps", for example, when ntp decides to set your clock backwards
276 from the wrong date of 2014-01-01 to 2008-01-01, a watcher that is 277 from the wrong date of 2014-01-01 to 2008-01-01, a watcher that is
277 supposed to fire "after" a second might actually take six years to 278 supposed to fire "after a second" might actually take six years to
278 finally fire. 279 finally fire.
279 280
280 AnyEvent cannot compensate for this. The only event loop that is 281 AnyEvent cannot compensate for this. The only event loop that is
281 conscious about these issues is EV, which offers both relative 282 conscious of these issues is EV, which offers both relative (ev_timer,
282 (ev_timer, based on true relative time) and absolute (ev_periodic, based 283 based on true relative time) and absolute (ev_periodic, based on
283 on wallclock time) timers. 284 wallclock time) timers.
284 285
285 AnyEvent always prefers relative timers, if available, matching the 286 AnyEvent always prefers relative timers, if available, matching the
286 AnyEvent API. 287 AnyEvent API.
287 288
288 AnyEvent has two additional methods that return the "current time": 289 AnyEvent has two additional methods that return the "current time":
307 *In almost all cases (in all cases if you don't care), this is the 308 *In almost all cases (in all cases if you don't care), this is the
308 function to call when you want to know the current time.* 309 function to call when you want to know the current time.*
309 310
310 This function is also often faster then "AnyEvent->time", and thus 311 This function is also often faster then "AnyEvent->time", and thus
311 the preferred method if you want some timestamp (for example, 312 the preferred method if you want some timestamp (for example,
312 AnyEvent::Handle uses this to update it's activity timeouts). 313 AnyEvent::Handle uses this to update its activity timeouts).
313 314
314 The rest of this section is only of relevance if you try to be very 315 The rest of this section is only of relevance if you try to be very
315 exact with your timing, you can skip it without bad conscience. 316 exact with your timing; you can skip it without a bad conscience.
316 317
317 For a practical example of when these times differ, consider 318 For a practical example of when these times differ, consider
318 Event::Lib and EV and the following set-up: 319 Event::Lib and EV and the following set-up:
319 320
320 The event loop is running and has just invoked one of your callback 321 The event loop is running and has just invoked one of your callbacks
321 at time=500 (assume no other callbacks delay processing). In your 322 at time=500 (assume no other callbacks delay processing). In your
322 callback, you wait a second by executing "sleep 1" (blocking the 323 callback, you wait a second by executing "sleep 1" (blocking the
323 process for a second) and then (at time=501) you create a relative 324 process for a second) and then (at time=501) you create a relative
324 timer that fires after three seconds. 325 timer that fires after three seconds.
325 326
346 can get whatever behaviour you want with any event loop, by taking 347 can get whatever behaviour you want with any event loop, by taking
347 the difference between "AnyEvent->time" and "AnyEvent->now" into 348 the difference between "AnyEvent->time" and "AnyEvent->now" into
348 account. 349 account.
349 350
350 AnyEvent->now_update 351 AnyEvent->now_update
351 Some event loops (such as EV or AnyEvent::Impl::Perl) cache the 352 Some event loops (such as EV or AnyEvent::Loop) cache the current
352 current time for each loop iteration (see the discussion of 353 time for each loop iteration (see the discussion of AnyEvent->now,
353 AnyEvent->now, above). 354 above).
354 355
355 When a callback runs for a long time (or when the process sleeps), 356 When a callback runs for a long time (or when the process sleeps),
356 then this "current" time will differ substantially from the real 357 then this "current" time will differ substantially from the real
357 time, which might affect timers and time-outs. 358 time, which might affect timers and time-outs.
358 359
402 will not restart syscalls (that includes Async::Interrupt and AnyEvent's 403 will not restart syscalls (that includes Async::Interrupt and AnyEvent's
403 pure perl implementation). 404 pure perl implementation).
404 405
405 Safe/Unsafe Signals 406 Safe/Unsafe Signals
406 Perl signals can be either "safe" (synchronous to opcode handling) or 407 Perl signals can be either "safe" (synchronous to opcode handling) or
407 "unsafe" (asynchronous) - the former might get delayed indefinitely, the 408 "unsafe" (asynchronous) - the former might delay signal delivery
408 latter might corrupt your memory. 409 indefinitely, the latter might corrupt your memory.
409 410
410 AnyEvent signal handlers are, in addition, synchronous to the event 411 AnyEvent signal handlers are, in addition, synchronous to the event
411 loop, i.e. they will not interrupt your running perl program but will 412 loop, i.e. they will not interrupt your running perl program but will
412 only be called as part of the normal event handling (just like timer, 413 only be called as part of the normal event handling (just like timer,
413 I/O etc. callbacks, too). 414 I/O etc. callbacks, too).
414 415
415 Signal Races, Delays and Workarounds 416 Signal Races, Delays and Workarounds
416 Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching 417 Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
417 callbacks to signals in a generic way, which is a pity, as you cannot do 418 callbacks to signals in a generic way, which is a pity, as you cannot do
418 race-free signal handling in perl, requiring C libraries for this. 419 race-free signal handling in perl, requiring C libraries for this.
419 AnyEvent will try to do it's best, which means in some cases, signals 420 AnyEvent will try to do its best, which means in some cases, signals
420 will be delayed. The maximum time a signal might be delayed is specified 421 will be delayed. The maximum time a signal might be delayed is 10
421 in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable 422 seconds by default, but can be overriden via
422 can be changed only before the first signal watcher is created, and 423 $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} or $AnyEvent::MAX_SIGNAL_LATENCY
423 should be left alone otherwise. This variable determines how often 424 - see the Ö<ENVIRONMENT VARIABLES> section for details.
424 AnyEvent polls for signals (in case a wake-up was missed). Higher values
425 will cause fewer spurious wake-ups, which is better for power and CPU
426 saving.
427 425
428 All these problems can be avoided by installing the optional 426 All these problems can be avoided by installing the optional
429 Async::Interrupt module, which works with most event loops. It will not 427 Async::Interrupt module, which works with most event loops. It will not
430 work with inherently broken event loops such as Event or Event::Lib (and 428 work with inherently broken event loops such as Event or Event::Lib (and
431 not with POE currently, as POE does it's own workaround with one-second
432 latency). For those, you just have to suffer the delays. 429 not with POE currently). For those, you just have to suffer the delays.
433 430
434 CHILD PROCESS WATCHERS 431 CHILD PROCESS WATCHERS
435 $w = AnyEvent->child (pid => <process id>, cb => <callback>); 432 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
436 433
437 You can also watch on a child process exit and catch its exit status. 434 You can also watch for a child process exit and catch its exit status.
438 435
439 The child process is specified by the "pid" argument (one some backends, 436 The child process is specified by the "pid" argument (on some backends,
440 using 0 watches for any child process exit, on others this will croak). 437 using 0 watches for any child process exit, on others this will croak).
441 The watcher will be triggered only when the child process has finished 438 The watcher will be triggered only when the child process has finished
442 and an exit status is available, not on any trace events 439 and an exit status is available, not on any trace events
443 (stopped/continued). 440 (stopped/continued).
444 441
465 This means you cannot create a child watcher as the very first thing in 462 This means you cannot create a child watcher as the very first thing in
466 an AnyEvent program, you *have* to create at least one watcher before 463 an AnyEvent program, you *have* to create at least one watcher before
467 you "fork" the child (alternatively, you can call "AnyEvent::detect"). 464 you "fork" the child (alternatively, you can call "AnyEvent::detect").
468 465
469 As most event loops do not support waiting for child events, they will 466 As most event loops do not support waiting for child events, they will
470 be emulated by AnyEvent in most cases, in which the latency and race 467 be emulated by AnyEvent in most cases, in which case the latency and
471 problems mentioned in the description of signal watchers apply. 468 race problems mentioned in the description of signal watchers apply.
472 469
473 Example: fork a process and wait for it 470 Example: fork a process and wait for it
474 471
475 my $done = AnyEvent->condvar; 472 my $done = AnyEvent->condvar;
476 473
477 my $pid = fork or exit 5; 474 my $pid = fork or exit 5;
478 475
479 my $w = AnyEvent->child ( 476 my $w = AnyEvent->child (
480 pid => $pid, 477 pid => $pid,
481 cb => sub { 478 cb => sub {
482 my ($pid, $status) = @_; 479 my ($pid, $status) = @_;
483 warn "pid $pid exited with status $status"; 480 warn "pid $pid exited with status $status";
484 $done->send; 481 $done->send;
485 }, 482 },
486 ); 483 );
487 484
488 # do something else, then wait for process exit 485 # do something else, then wait for process exit
489 $done->recv; 486 $done->recv;
490 487
491 IDLE WATCHERS 488 IDLE WATCHERS
492 $w = AnyEvent->idle (cb => <callback>); 489 $w = AnyEvent->idle (cb => <callback>);
493 490
494 Repeatedly invoke the callback after the process becomes idle, until 491 This will repeatedly invoke the callback after the process becomes idle,
495 either the watcher is destroyed or new events have been detected. 492 until either the watcher is destroyed or new events have been detected.
496 493
497 Idle watchers are useful when there is a need to do something, but it is 494 Idle watchers are useful when there is a need to do something, but it is
498 not so important (or wise) to do it instantly. The callback will be 495 not so important (or wise) to do it instantly. The callback will be
499 invoked only when there is "nothing better to do", which is usually 496 invoked only when there is "nothing better to do", which is usually
500 defined as "all outstanding events have been handled and no new events 497 defined as "all outstanding events have been handled and no new events
539 536
540 AnyEvent is slightly different: it expects somebody else to run the 537 AnyEvent is slightly different: it expects somebody else to run the
541 event loop and will only block when necessary (usually when told by the 538 event loop and will only block when necessary (usually when told by the
542 user). 539 user).
543 540
544 The instrument to do that is called a "condition variable", so called 541 The tool to do that is called a "condition variable", so called because
545 because they represent a condition that must become true. 542 they represent a condition that must become true.
546 543
547 Now is probably a good time to look at the examples further below. 544 Now is probably a good time to look at the examples further below.
548 545
549 Condition variables can be created by calling the "AnyEvent->condvar" 546 Condition variables can be created by calling the "AnyEvent->condvar"
550 method, usually without arguments. The only argument pair allowed is 547 method, usually without arguments. The only argument pair allowed is
555 After creation, the condition variable is "false" until it becomes 552 After creation, the condition variable is "false" until it becomes
556 "true" by calling the "send" method (or calling the condition variable 553 "true" by calling the "send" method (or calling the condition variable
557 as if it were a callback, read about the caveats in the description for 554 as if it were a callback, read about the caveats in the description for
558 the "->send" method). 555 the "->send" method).
559 556
560 Condition variables are similar to callbacks, except that you can 557 Since condition variables are the most complex part of the AnyEvent API,
561 optionally wait for them. They can also be called merge points - points 558 here are some different mental models of what they are - pick the ones
562 in time where multiple outstanding events have been processed. And yet 559 you can connect to:
563 another way to call them is transactions - each condition variable can 560
564 be used to represent a transaction, which finishes at some point and 561 * Condition variables are like callbacks - you can call them (and pass
565 delivers a result. And yet some people know them as "futures" - a 562 them instead of callbacks). Unlike callbacks however, you can also
566 promise to compute/deliver something that you can wait for. 563 wait for them to be called.
564
565 * Condition variables are signals - one side can emit or send them,
566 the other side can wait for them, or install a handler that is
567 called when the signal fires.
568
569 * Condition variables are like "Merge Points" - points in your program
570 where you merge multiple independent results/control flows into one.
571
572 * Condition variables represent a transaction - functions that start
573 some kind of transaction can return them, leaving the caller the
574 choice between waiting in a blocking fashion, or setting a callback.
575
576 * Condition variables represent future values, or promises to deliver
577 some result, long before the result is available.
567 578
568 Condition variables are very useful to signal that something has 579 Condition variables are very useful to signal that something has
569 finished, for example, if you write a module that does asynchronous http 580 finished, for example, if you write a module that does asynchronous http
570 requests, then a condition variable would be the ideal candidate to 581 requests, then a condition variable would be the ideal candidate to
571 signal the availability of results. The user can either act when the 582 signal the availability of results. The user can either act when the
584 595
585 Condition variables are represented by hash refs in perl, and the keys 596 Condition variables are represented by hash refs in perl, and the keys
586 used by AnyEvent itself are all named "_ae_XXX" to make subclassing easy 597 used by AnyEvent itself are all named "_ae_XXX" to make subclassing easy
587 (it is often useful to build your own transaction class on top of 598 (it is often useful to build your own transaction class on top of
588 AnyEvent). To subclass, use "AnyEvent::CondVar" as base class and call 599 AnyEvent). To subclass, use "AnyEvent::CondVar" as base class and call
589 it's "new" method in your own "new" method. 600 its "new" method in your own "new" method.
590 601
591 There are two "sides" to a condition variable - the "producer side" 602 There are two "sides" to a condition variable - the "producer side"
592 which eventually calls "-> send", and the "consumer side", which waits 603 which eventually calls "-> send", and the "consumer side", which waits
593 for the send to occur. 604 for the send to occur.
594 605
654 Condition variables are overloaded so one can call them directly (as 665 Condition variables are overloaded so one can call them directly (as
655 if they were a code reference). Calling them directly is the same as 666 if they were a code reference). Calling them directly is the same as
656 calling "send". 667 calling "send".
657 668
658 $cv->croak ($error) 669 $cv->croak ($error)
659 Similar to send, but causes all call's to "->recv" to invoke 670 Similar to send, but causes all calls to "->recv" to invoke
660 "Carp::croak" with the given error message/object/scalar. 671 "Carp::croak" with the given error message/object/scalar.
661 672
662 This can be used to signal any errors to the condition variable 673 This can be used to signal any errors to the condition variable
663 user/consumer. Doing it this way instead of calling "croak" directly 674 user/consumer. Doing it this way instead of calling "croak" directly
664 delays the error detetcion, but has the overwhelmign advantage that 675 delays the error detection, but has the overwhelming advantage that
665 it diagnoses the error at the place where the result is expected, 676 it diagnoses the error at the place where the result is expected,
666 and not deep in some event clalback without connection to the actual 677 and not deep in some event callback with no connection to the actual
667 code causing the problem. 678 code causing the problem.
668 679
669 $cv->begin ([group callback]) 680 $cv->begin ([group callback])
670 $cv->end 681 $cv->end
671 These two methods can be used to combine many transactions/events 682 These two methods can be used to combine many transactions/events
708 there is one call to "begin", so the condvar waits for all calls to 719 there is one call to "begin", so the condvar waits for all calls to
709 "end" before sending. 720 "end" before sending.
710 721
711 The ping example mentioned above is slightly more complicated, as 722 The ping example mentioned above is slightly more complicated, as
712 the there are results to be passwd back, and the number of tasks 723 the there are results to be passwd back, and the number of tasks
713 that are begung can potentially be zero: 724 that are begun can potentially be zero:
714 725
715 my $cv = AnyEvent->condvar; 726 my $cv = AnyEvent->condvar;
716 727
717 my %result; 728 my %result;
718 $cv->begin (sub { shift->send (\%result) }); 729 $cv->begin (sub { shift->send (\%result) });
739 callback to be called once the counter reaches 0, and second, it 750 callback to be called once the counter reaches 0, and second, it
740 ensures that "send" is called even when "no" hosts are being pinged 751 ensures that "send" is called even when "no" hosts are being pinged
741 (the loop doesn't execute once). 752 (the loop doesn't execute once).
742 753
743 This is the general pattern when you "fan out" into multiple (but 754 This is the general pattern when you "fan out" into multiple (but
744 potentially none) subrequests: use an outer "begin"/"end" pair to 755 potentially zero) subrequests: use an outer "begin"/"end" pair to
745 set the callback and ensure "end" is called at least once, and then, 756 set the callback and ensure "end" is called at least once, and then,
746 for each subrequest you start, call "begin" and for each subrequest 757 for each subrequest you start, call "begin" and for each subrequest
747 you finish, call "end". 758 you finish, call "end".
748 759
749 METHODS FOR CONSUMERS 760 METHODS FOR CONSUMERS
750 These methods should only be used by the consuming side, i.e. the code 761 These methods should only be used by the consuming side, i.e. the code
751 awaits the condition. 762 awaits the condition.
752 763
753 $cv->recv 764 $cv->recv
754 Wait (blocking if necessary) until the "->send" or "->croak" methods 765 Wait (blocking if necessary) until the "->send" or "->croak" methods
755 have been called on c<$cv>, while servicing other watchers normally. 766 have been called on $cv, while servicing other watchers normally.
756 767
757 You can only wait once on a condition - additional calls are valid 768 You can only wait once on a condition - additional calls are valid
758 but will return immediately. 769 but will return immediately.
759 770
760 If an error condition has been set by calling "->croak", then this 771 If an error condition has been set by calling "->croak", then this
777 example, by coupling condition variables with some kind of request 788 example, by coupling condition variables with some kind of request
778 results and supporting callbacks so the caller knows that getting 789 results and supporting callbacks so the caller knows that getting
779 the result will not block, while still supporting blocking waits if 790 the result will not block, while still supporting blocking waits if
780 the caller so desires). 791 the caller so desires).
781 792
782 You can ensure that "-recv" never blocks by setting a callback and 793 You can ensure that "->recv" never blocks by setting a callback and
783 only calling "->recv" from within that callback (or at a later 794 only calling "->recv" from within that callback (or at a later
784 time). This will work even when the event loop does not support 795 time). This will work even when the event loop does not support
785 blocking waits otherwise. 796 blocking waits otherwise.
786 797
787 $bool = $cv->ready 798 $bool = $cv->ready
790 801
791 $cb = $cv->cb ($cb->($cv)) 802 $cb = $cv->cb ($cb->($cv))
792 This is a mutator function that returns the callback set and 803 This is a mutator function that returns the callback set and
793 optionally replaces it before doing so. 804 optionally replaces it before doing so.
794 805
795 The callback will be called when the condition becomes (or already 806 The callback will be called when the condition becomes "true", i.e.
796 was) "true", i.e. when "send" or "croak" are called (or were 807 when "send" or "croak" are called, with the only argument being the
797 called), with the only argument being the condition variable itself. 808 condition variable itself. If the condition is already true, the
798 Calling "recv" inside the callback or at any later time is 809 callback is called immediately when it is set. Calling "recv" inside
799 guaranteed not to block. 810 the callback or at any later time is guaranteed not to block.
800 811
801SUPPORTED EVENT LOOPS/BACKENDS 812SUPPORTED EVENT LOOPS/BACKENDS
802 The available backend classes are (every class has its own manpage): 813 The available backend classes are (every class has its own manpage):
803 814
804 Backends that are autoprobed when no other event loop can be found. 815 Backends that are autoprobed when no other event loop can be found.
806 use. If EV is not installed, then AnyEvent will fall back to its own 817 use. If EV is not installed, then AnyEvent will fall back to its own
807 pure-perl implementation, which is available everywhere as it comes 818 pure-perl implementation, which is available everywhere as it comes
808 with AnyEvent itself. 819 with AnyEvent itself.
809 820
810 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 821 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
811 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 822 AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
812 823
813 Backends that are transparently being picked up when they are used. 824 Backends that are transparently being picked up when they are used.
814 These will be used when they are currently loaded when the first 825 These will be used if they are already loaded when the first watcher
815 watcher is created, in which case it is assumed that the application 826 is created, in which case it is assumed that the application is
816 is using them. This means that AnyEvent will automatically pick the 827 using them. This means that AnyEvent will automatically pick the
817 right backend when the main program loads an event module before 828 right backend when the main program loads an event module before
818 anything starts to create watchers. Nothing special needs to be done 829 anything starts to create watchers. Nothing special needs to be done
819 by the main program. 830 by the main program.
820 831
821 AnyEvent::Impl::Event based on Event, very stable, few glitches. 832 AnyEvent::Impl::Event based on Event, very stable, few glitches.
822 AnyEvent::Impl::Glib based on Glib, slow but very stable. 833 AnyEvent::Impl::Glib based on Glib, slow but very stable.
823 AnyEvent::Impl::Tk based on Tk, very broken. 834 AnyEvent::Impl::Tk based on Tk, very broken.
824 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 835 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
825 AnyEvent::Impl::POE based on POE, very slow, some limitations. 836 AnyEvent::Impl::POE based on POE, very slow, some limitations.
826 AnyEvent::Impl::Irssi used when running within irssi. 837 AnyEvent::Impl::Irssi used when running within irssi.
838 AnyEvent::Impl::IOAsync based on IO::Async.
839 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
840 AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
827 841
828 Backends with special needs. 842 Backends with special needs.
829 Qt requires the Qt::Application to be instantiated first, but will 843 Qt requires the Qt::Application to be instantiated first, but will
830 otherwise be picked up automatically. As long as the main program 844 otherwise be picked up automatically. As long as the main program
831 instantiates the application before any AnyEvent watchers are 845 instantiates the application before any AnyEvent watchers are
832 created, everything should just work. 846 created, everything should just work.
833 847
834 AnyEvent::Impl::Qt based on Qt. 848 AnyEvent::Impl::Qt based on Qt.
835 849
836 Support for IO::Async can only be partial, as it is too broken and
837 architecturally limited to even support the AnyEvent API. It also is
838 the only event loop that needs the loop to be set explicitly, so it
839 can only be used by a main program knowing about AnyEvent. See
840 AnyEvent::Impl::Async for the gory details.
841
842 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
843
844 Event loops that are indirectly supported via other backends. 850 Event loops that are indirectly supported via other backends.
845 Some event loops can be supported via other modules: 851 Some event loops can be supported via other modules:
846 852
847 There is no direct support for WxWidgets (Wx) or Prima. 853 There is no direct support for WxWidgets (Wx) or Prima.
848 854
866 Contains "undef" until the first watcher is being created, before 872 Contains "undef" until the first watcher is being created, before
867 the backend has been autodetected. 873 the backend has been autodetected.
868 874
869 Afterwards it contains the event model that is being used, which is 875 Afterwards it contains the event model that is being used, which is
870 the name of the Perl class implementing the model. This class is 876 the name of the Perl class implementing the model. This class is
871 usually one of the "AnyEvent::Impl:xxx" modules, but can be any 877 usually one of the "AnyEvent::Impl::xxx" modules, but can be any
872 other class in the case AnyEvent has been extended at runtime (e.g. 878 other class in the case AnyEvent has been extended at runtime (e.g.
873 in *rxvt-unicode* it will be "urxvt::anyevent"). 879 in *rxvt-unicode* it will be "urxvt::anyevent").
874 880
875 AnyEvent::detect 881 AnyEvent::detect
876 Returns $AnyEvent::MODEL, forcing autodetection of the event model 882 Returns $AnyEvent::MODEL, forcing autodetection of the event model
877 if necessary. You should only call this function right before you 883 if necessary. You should only call this function right before you
878 would have created an AnyEvent watcher anyway, that is, as late as 884 would have created an AnyEvent watcher anyway, that is, as late as
879 possible at runtime, and not e.g. while initialising of your module. 885 possible at runtime, and not e.g. during initialisation of your
886 module.
887
888 The effect of calling this function is as if a watcher had been
889 created (specifically, actions that happen "when the first watcher
890 is created" happen when calling detetc as well).
880 891
881 If you need to do some initialisation before AnyEvent watchers are 892 If you need to do some initialisation before AnyEvent watchers are
882 created, use "post_detect". 893 created, use "post_detect".
883 894
884 $guard = AnyEvent::post_detect { BLOCK } 895 $guard = AnyEvent::post_detect { BLOCK }
885 Arranges for the code block to be executed as soon as the event 896 Arranges for the code block to be executed as soon as the event
886 model is autodetected (or immediately if this has already happened). 897 model is autodetected (or immediately if that has already happened).
887 898
888 The block will be executed *after* the actual backend has been 899 The block will be executed *after* the actual backend has been
889 detected ($AnyEvent::MODEL is set), but *before* any watchers have 900 detected ($AnyEvent::MODEL is set), but *before* any watchers have
890 been created, so it is possible to e.g. patch @AnyEvent::ISA or do 901 been created, so it is possible to e.g. patch @AnyEvent::ISA or do
891 other initialisations - see the sources of AnyEvent::Strict or 902 other initialisations - see the sources of AnyEvent::Strict or
900 object that automatically removes the callback again when it is 911 object that automatically removes the callback again when it is
901 destroyed (or "undef" when the hook was immediately executed). See 912 destroyed (or "undef" when the hook was immediately executed). See
902 AnyEvent::AIO for a case where this is useful. 913 AnyEvent::AIO for a case where this is useful.
903 914
904 Example: Create a watcher for the IO::AIO module and store it in 915 Example: Create a watcher for the IO::AIO module and store it in
905 $WATCHER. Only do so after the event loop is initialised, though. 916 $WATCHER, but do so only do so after the event loop is initialised.
906 917
907 our WATCHER; 918 our WATCHER;
908 919
909 my $guard = AnyEvent::post_detect { 920 my $guard = AnyEvent::post_detect {
910 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); 921 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
917 928
918 $WATCHER ||= $guard; 929 $WATCHER ||= $guard;
919 930
920 @AnyEvent::post_detect 931 @AnyEvent::post_detect
921 If there are any code references in this array (you can "push" to it 932 If there are any code references in this array (you can "push" to it
922 before or after loading AnyEvent), then they will called directly 933 before or after loading AnyEvent), then they will be called directly
923 after the event loop has been chosen. 934 after the event loop has been chosen.
924 935
925 You should check $AnyEvent::MODEL before adding to this array, 936 You should check $AnyEvent::MODEL before adding to this array,
926 though: if it is defined then the event loop has already been 937 though: if it is defined then the event loop has already been
927 detected, and the array will be ignored. 938 detected, and the array will be ignored.
946 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent 957 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
947 # as soon as it is 958 # as soon as it is
948 push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; 959 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
949 } 960 }
950 961
962 AnyEvent::postpone { BLOCK }
963 Arranges for the block to be executed as soon as possible, but not
964 before the call itself returns. In practise, the block will be
965 executed just before the event loop polls for new events, or shortly
966 afterwards.
967
968 This function never returns anything (to make the "return postpone {
969 ... }" idiom more useful.
970
971 To understand the usefulness of this function, consider a function
972 that asynchronously does something for you and returns some
973 transaction object or guard to let you cancel the operation. For
974 example, "AnyEvent::Socket::tcp_connect":
975
976 # start a conenction attempt unless one is active
977 $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
978 delete $self->{connect_guard};
979 ...
980 };
981
982 Imagine that this function could instantly call the callback, for
983 example, because it detects an obvious error such as a negative port
984 number. Invoking the callback before the function returns causes
985 problems however: the callback will be called and will try to delete
986 the guard object. But since the function hasn't returned yet, there
987 is nothing to delete. When the function eventually returns it will
988 assign the guard object to "$self->{connect_guard}", where it will
989 likely never be deleted, so the program thinks it is still trying to
990 connect.
991
992 This is where "AnyEvent::postpone" should be used. Instead of
993 calling the callback directly on error:
994
995 $cb->(undef), return # signal error to callback, BAD!
996 if $some_error_condition;
997
998 It should use "postpone":
999
1000 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1001 if $some_error_condition;
1002
1003 AnyEvent::log $level, $msg[, @args]
1004 Log the given $msg at the given $level.
1005
1006 If AnyEvent::Log is not loaded then this function makes a simple
1007 test to see whether the message will be logged. If the test succeeds
1008 it will load AnyEvent::Log and call "AnyEvent::Log::log" -
1009 consequently, look at the AnyEvent::Log documentation for details.
1010
1011 If the test fails it will simply return. Right now this happens when
1012 a numerical loglevel is used and it is larger than the level
1013 specified via $ENV{PERL_ANYEVENT_VERBOSE}.
1014
1015 If you want to sprinkle loads of logging calls around your code,
1016 consider creating a logger callback with the "AnyEvent::Log::logger"
1017 function, which can reduce typing, codesize and can reduce the
1018 logging overhead enourmously.
1019
951WHAT TO DO IN A MODULE 1020WHAT TO DO IN A MODULE
952 As a module author, you should "use AnyEvent" and call AnyEvent methods 1021 As a module author, you should "use AnyEvent" and call AnyEvent methods
953 freely, but you should not load a specific event module or rely on it. 1022 freely, but you should not load a specific event module or rely on it.
954 1023
955 Be careful when you create watchers in the module body - AnyEvent will 1024 Be careful when you create watchers in the module body - AnyEvent will
962 stall the whole program, and the whole point of using events is to stay 1031 stall the whole program, and the whole point of using events is to stay
963 interactive. 1032 interactive.
964 1033
965 It is fine, however, to call "->recv" when the user of your module 1034 It is fine, however, to call "->recv" when the user of your module
966 requests it (i.e. if you create a http request object ad have a method 1035 requests it (i.e. if you create a http request object ad have a method
967 called "results" that returns the results, it should call "->recv" 1036 called "results" that returns the results, it may call "->recv" freely,
968 freely, as the user of your module knows what she is doing. always). 1037 as the user of your module knows what she is doing. Always).
969 1038
970WHAT TO DO IN THE MAIN PROGRAM 1039WHAT TO DO IN THE MAIN PROGRAM
971 There will always be a single main program - the only place that should 1040 There will always be a single main program - the only place that should
972 dictate which event model to use. 1041 dictate which event model to use.
973 1042
974 If it doesn't care, it can just "use AnyEvent" and use it itself, or not 1043 If the program is not event-based, it need not do anything special, even
975 do anything special (it does not need to be event-based) and let 1044 when it depends on a module that uses an AnyEvent. If the program itself
976 AnyEvent decide which implementation to chose if some module relies on 1045 uses AnyEvent, but does not care which event loop is used, all it needs
977 it. 1046 to do is "use AnyEvent". In either case, AnyEvent will choose the best
1047 available loop implementation.
978 1048
979 If the main program relies on a specific event model - for example, in 1049 If the main program relies on a specific event model - for example, in
980 Gtk2 programs you have to rely on the Glib module - you should load the 1050 Gtk2 programs you have to rely on the Glib module - you should load the
981 event module before loading AnyEvent or any module that uses it: 1051 event module before loading AnyEvent or any module that uses it:
982 generally speaking, you should load it as early as possible. The reason 1052 generally speaking, you should load it as early as possible. The reason
983 is that modules might create watchers when they are loaded, and AnyEvent 1053 is that modules might create watchers when they are loaded, and AnyEvent
984 will decide on the event model to use as soon as it creates watchers, 1054 will decide on the event model to use as soon as it creates watchers,
985 and it might chose the wrong one unless you load the correct one 1055 and it might choose the wrong one unless you load the correct one
986 yourself. 1056 yourself.
987 1057
988 You can chose to use a pure-perl implementation by loading the 1058 You can chose to use a pure-perl implementation by loading the
989 "AnyEvent::Impl::Perl" module, which gives you similar behaviour 1059 "AnyEvent::Loop" module, which gives you similar behaviour everywhere,
990 everywhere, but letting AnyEvent chose the model is generally better. 1060 but letting AnyEvent chose the model is generally better.
991 1061
992 MAINLOOP EMULATION 1062 MAINLOOP EMULATION
993 Sometimes (often for short test scripts, or even standalone programs who 1063 Sometimes (often for short test scripts, or even standalone programs who
994 only want to use AnyEvent), you do not want to run a specific event 1064 only want to use AnyEvent), you do not want to run a specific event
995 loop. 1065 loop.
1007 1077
1008OTHER MODULES 1078OTHER MODULES
1009 The following is a non-exhaustive list of additional modules that use 1079 The following is a non-exhaustive list of additional modules that use
1010 AnyEvent as a client and can therefore be mixed easily with other 1080 AnyEvent as a client and can therefore be mixed easily with other
1011 AnyEvent modules and other event loops in the same program. Some of the 1081 AnyEvent modules and other event loops in the same program. Some of the
1012 modules come with AnyEvent, most are available via CPAN. 1082 modules come as part of AnyEvent, the others are available via CPAN (see
1083 <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer
1084 non-exhaustive list), and the list is heavily biased towards modules of
1085 the AnyEvent author himself :)
1013 1086
1014 AnyEvent::Util 1087 AnyEvent::Util
1015 Contains various utility functions that replace often-used but 1088 Contains various utility functions that replace often-used blocking
1016 blocking functions such as "inet_aton" by event-/callback-based 1089 functions such as "inet_aton" with event/callback-based versions.
1017 versions.
1018 1090
1019 AnyEvent::Socket 1091 AnyEvent::Socket
1020 Provides various utility functions for (internet protocol) sockets, 1092 Provides various utility functions for (internet protocol) sockets,
1021 addresses and name resolution. Also functions to create non-blocking 1093 addresses and name resolution. Also functions to create non-blocking
1022 tcp connections or tcp servers, with IPv6 and SRV record support and 1094 tcp connections or tcp servers, with IPv6 and SRV record support and
1023 more. 1095 more.
1024 1096
1025 AnyEvent::Handle 1097 AnyEvent::Handle
1026 Provide read and write buffers, manages watchers for reads and 1098 Provide read and write buffers, manages watchers for reads and
1027 writes, supports raw and formatted I/O, I/O queued and fully 1099 writes, supports raw and formatted I/O, I/O queued and fully
1028 transparent and non-blocking SSL/TLS (via AnyEvent::TLS. 1100 transparent and non-blocking SSL/TLS (via AnyEvent::TLS).
1029 1101
1030 AnyEvent::DNS 1102 AnyEvent::DNS
1031 Provides rich asynchronous DNS resolver capabilities. 1103 Provides rich asynchronous DNS resolver capabilities.
1032 1104
1105 AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD,
1106 AnyEvent::IGS, AnyEvent::FCP
1107 Implement event-based interfaces to the protocols of the same name
1108 (for the curious, IGS is the International Go Server and FCP is the
1109 Freenet Client Protocol).
1110
1033 AnyEvent::HTTP 1111 AnyEvent::AIO
1034 A simple-to-use HTTP library that is capable of making a lot of 1112 Truly asynchronous (as opposed to non-blocking) I/O, should be in
1035 concurrent HTTP requests. 1113 the toolbox of every event programmer. AnyEvent::AIO transparently
1114 fuses IO::AIO and AnyEvent together, giving AnyEvent access to
1115 event-based file I/O, and much more.
1116
1117 AnyEvent::Filesys::Notify
1118 AnyEvent is good for non-blocking stuff, but it can't detect file or
1119 path changes (e.g. "watch this directory for new files", "watch this
1120 file for changes"). The AnyEvent::Filesys::Notify module promises to
1121 do just that in a portbale fashion, supporting inotify on GNU/Linux
1122 and some weird, without doubt broken, stuff on OS X to monitor
1123 files. It can fall back to blocking scans at regular intervals
1124 transparently on other platforms, so it's about as portable as it
1125 gets.
1126
1127 (I haven't used it myself, but I haven't heard anybody complaining
1128 about it yet).
1129
1130 AnyEvent::DBI
1131 Executes DBI requests asynchronously in a proxy process for you,
1132 notifying you in an event-based way when the operation is finished.
1036 1133
1037 AnyEvent::HTTPD 1134 AnyEvent::HTTPD
1038 Provides a simple web application server framework. 1135 A simple embedded webserver.
1039 1136
1040 AnyEvent::FastPing 1137 AnyEvent::FastPing
1041 The fastest ping in the west. 1138 The fastest ping in the west.
1042 1139
1043 AnyEvent::DBI
1044 Executes DBI requests asynchronously in a proxy process.
1045
1046 AnyEvent::AIO
1047 Truly asynchronous I/O, should be in the toolbox of every event
1048 programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
1049 together.
1050
1051 AnyEvent::BDB
1052 Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently
1053 fuses BDB and AnyEvent together.
1054
1055 AnyEvent::GPSD
1056 A non-blocking interface to gpsd, a daemon delivering GPS
1057 information.
1058
1059 AnyEvent::IRC
1060 AnyEvent based IRC client module family (replacing the older
1061 Net::IRC3).
1062
1063 AnyEvent::XMPP
1064 AnyEvent based XMPP (Jabber protocol) module family (replacing the
1065 older Net::XMPP2>.
1066
1067 AnyEvent::IGS
1068 A non-blocking interface to the Internet Go Server protocol (used by
1069 App::IGS).
1070
1071 Net::FCP
1072 AnyEvent-based implementation of the Freenet Client Protocol,
1073 birthplace of AnyEvent.
1074
1075 Event::ExecFlow
1076 High level API for event-based execution flow control.
1077
1078 Coro 1140 Coro
1079 Has special support for AnyEvent via Coro::AnyEvent. 1141 Has special support for AnyEvent via Coro::AnyEvent, which allows
1142 you to simply invert the flow control - don't call us, we will call
1143 you:
1144
1145 async {
1146 Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
1147 print "5 seconds later!\n";
1148
1149 Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
1150 my $line = <STDIN>; # works for ttys
1151
1152 AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
1153 my ($body, $hdr) = Coro::rouse_wait;
1154 };
1080 1155
1081SIMPLIFIED AE API 1156SIMPLIFIED AE API
1082 Starting with version 5.0, AnyEvent officially supports a second, much 1157 Starting with version 5.0, AnyEvent officially supports a second, much
1083 simpler, API that is designed to reduce the calling, typing and memory 1158 simpler, API that is designed to reduce the calling, typing and memory
1084 overhead by using function call syntax and a fixed number of parameters. 1159 overhead by using function call syntax and a fixed number of parameters.
1100 The pure perl event loop simply re-throws the exception (usually within 1175 The pure perl event loop simply re-throws the exception (usually within
1101 "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", 1176 "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()",
1102 Glib uses "install_exception_handler" and so on. 1177 Glib uses "install_exception_handler" and so on.
1103 1178
1104ENVIRONMENT VARIABLES 1179ENVIRONMENT VARIABLES
1105 The following environment variables are used by this module or its 1180 AnyEvent supports a number of environment variables that tune the
1106 submodules. 1181 runtime behaviour. They are usually evaluated when AnyEvent is loaded,
1182 initialised, or a submodule that uses them is loaded. Many of them also
1183 cause AnyEvent to load additional modules - for example,
1184 "PERL_ANYEVENT_DEBUG_WRAP" causes the AnyEvent::Debug module to be
1185 loaded.
1107 1186
1108 Note that AnyEvent will remove *all* environment variables starting with 1187 All the environment variables documented here start with
1109 "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is 1188 "PERL_ANYEVENT_", which is what AnyEvent considers its own namespace.
1110 enabled. 1189 Other modules are encouraged (but by no means required) to use
1190 "PERL_ANYEVENT_SUBMODULE" if they have registered the
1191 AnyEvent::Submodule namespace on CPAN, for any submodule. For example,
1192 AnyEvent::HTTP could be expected to use "PERL_ANYEVENT_HTTP_PROXY" (it
1193 should not access env variables starting with "AE_", see below).
1194
1195 All variables can also be set via the "AE_" prefix, that is, instead of
1196 setting "PERL_ANYEVENT_VERBOSE" you can also set "AE_VERBOSE". In case
1197 there is a clash btween anyevent and another program that uses
1198 "AE_something" you can set the corresponding "PERL_ANYEVENT_something"
1199 variable to the empty string, as those variables take precedence.
1200
1201 When AnyEvent is first loaded, it copies all "AE_xxx" env variables to
1202 their "PERL_ANYEVENT_xxx" counterpart unless that variable already
1203 exists. If taint mode is on, then AnyEvent will remove *all* environment
1204 variables starting with "PERL_ANYEVENT_" from %ENV (or replace them with
1205 "undef" or the empty string, if the corresaponding "AE_" variable is
1206 set).
1207
1208 The exact algorithm is currently:
1209
1210 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
1211 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
1212 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
1213
1214 This ensures that child processes will not see the "AE_" variables.
1215
1216 The following environment variables are currently known to AnyEvent:
1111 1217
1112 "PERL_ANYEVENT_VERBOSE" 1218 "PERL_ANYEVENT_VERBOSE"
1113 By default, AnyEvent will be completely silent except in fatal 1219 By default, AnyEvent will only log messages with loglevel 3
1114 conditions. You can set this environment variable to make AnyEvent 1220 ("critical") or higher (see AnyEvent::Log). You can set this
1221 environment variable to a numerical loglevel to make AnyEvent more
1115 more talkative. 1222 (or less) talkative.
1116 1223
1224 If you want to do more than just set the global logging level you
1225 should have a look at "PERL_ANYEVENT_LOG", which allows much more
1226 complex specifications.
1227
1228 When set to 0 ("off"), then no messages whatsoever will be logged
1229 with the default logging settings.
1230
1117 When set to 1 or higher, causes AnyEvent to warn about unexpected 1231 When set to 5 or higher ("warn"), causes AnyEvent to warn about
1118 conditions, such as not being able to load the event model specified 1232 unexpected conditions, such as not being able to load the event
1119 by "PERL_ANYEVENT_MODEL". 1233 model specified by "PERL_ANYEVENT_MODEL", or a guard callback
1234 throwing an exception - this is the minimum recommended level.
1120 1235
1121 When set to 2 or higher, cause AnyEvent to report to STDERR which 1236 When set to 7 or higher (info), cause AnyEvent to report which event
1122 event model it chooses. 1237 model it chooses.
1123 1238
1124 When set to 8 or higher, then AnyEvent will report extra information 1239 When set to 8 or higher (debug), then AnyEvent will report extra
1125 on which optional modules it loads and how it implements certain 1240 information on which optional modules it loads and how it implements
1126 features. 1241 certain features.
1242
1243 "PERL_ANYEVENT_LOG"
1244 Accepts rather complex logging specifications. For example, you
1245 could log all "debug" messages of some module to stderr, warnings
1246 and above to stderr, and errors and above to syslog, with:
1247
1248 PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
1249
1250 For the rather extensive details, see AnyEvent::Log.
1251
1252 This variable is evaluated when AnyEvent (or AnyEvent::Log) is
1253 loaded, so will take effect even before AnyEvent has initialised
1254 itself.
1255
1256 Note that specifying this environment variable causes the
1257 AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE"
1258 does not, so only using the latter saves a few hundred kB of memory
1259 until the first message is being logged.
1127 1260
1128 "PERL_ANYEVENT_STRICT" 1261 "PERL_ANYEVENT_STRICT"
1129 AnyEvent does not do much argument checking by default, as thorough 1262 AnyEvent does not do much argument checking by default, as thorough
1130 argument checking is very costly. Setting this variable to a true 1263 argument checking is very costly. Setting this variable to a true
1131 value will cause AnyEvent to load "AnyEvent::Strict" and then to 1264 value will cause AnyEvent to load "AnyEvent::Strict" and then to
1132 thoroughly check the arguments passed to most method calls. If it 1265 thoroughly check the arguments passed to most method calls. If it
1133 finds any problems, it will croak. 1266 finds any problems, it will croak.
1134 1267
1135 In other words, enables "strict" mode. 1268 In other words, enables "strict" mode.
1136 1269
1137 Unlike "use strict" (or it's modern cousin, "use common::sense", it 1270 Unlike "use strict" (or its modern cousin, "use common::sense", it
1138 is definitely recommended to keep it off in production. Keeping 1271 is definitely recommended to keep it off in production. Keeping
1139 "PERL_ANYEVENT_STRICT=1" in your environment while developing 1272 "PERL_ANYEVENT_STRICT=1" in your environment while developing
1140 programs can be very useful, however. 1273 programs can be very useful, however.
1141 1274
1275 "PERL_ANYEVENT_DEBUG_SHELL"
1276 If this env variable is nonempty, then its contents will be
1277 interpreted by "AnyEvent::Socket::parse_hostport" and
1278 "AnyEvent::Debug::shell" (after replacing every occurance of $$ by
1279 the process pid). The shell object is saved in
1280 $AnyEvent::Debug::SHELL.
1281
1282 This happens when the first watcher is created.
1283
1284 For example, to bind a debug shell on a unix domain socket in
1285 /tmp/debug<pid>.sock, you could use this:
1286
1287 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
1288 # connect with e.g.: socat readline /tmp/debug123.sock
1289
1290 Or to bind to tcp port 4545 on localhost:
1291
1292 PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
1293 # connect with e.g.: telnet localhost 4545
1294
1295 Note that creating sockets in /tmp or on localhost is very unsafe on
1296 multiuser systems.
1297
1298 "PERL_ANYEVENT_DEBUG_WRAP"
1299 Can be set to 0, 1 or 2 and enables wrapping of all watchers for
1300 debugging purposes. See "AnyEvent::Debug::wrap" for details.
1301
1142 "PERL_ANYEVENT_MODEL" 1302 "PERL_ANYEVENT_MODEL"
1143 This can be used to specify the event model to be used by AnyEvent, 1303 This can be used to specify the event model to be used by AnyEvent,
1144 before auto detection and -probing kicks in. It must be a string 1304 before auto detection and -probing kicks in.
1145 consisting entirely of ASCII letters. The string "AnyEvent::Impl::" 1305
1146 gets prepended and the resulting module name is loaded and if the 1306 It normally is a string consisting entirely of ASCII letters (e.g.
1147 load was successful, used as event model. If it fails to load 1307 "EV" or "IOAsync"). The string "AnyEvent::Impl::" gets prepended and
1308 the resulting module name is loaded and - if the load was successful
1309 - used as event model backend. If it fails to load then AnyEvent
1148 AnyEvent will proceed with auto detection and -probing. 1310 will proceed with auto detection and -probing.
1149 1311
1150 This functionality might change in future versions. 1312 If the string ends with "::" instead (e.g. "AnyEvent::Impl::EV::")
1313 then nothing gets prepended and the module name is used as-is (hint:
1314 "::" at the end of a string designates a module name and quotes it
1315 appropriately).
1151 1316
1152 For example, to force the pure perl model (AnyEvent::Impl::Perl) you 1317 For example, to force the pure perl model (AnyEvent::Loop::Perl) you
1153 could start your program like this: 1318 could start your program like this:
1154 1319
1155 PERL_ANYEVENT_MODEL=Perl perl ... 1320 PERL_ANYEVENT_MODEL=Perl perl ...
1156 1321
1157 "PERL_ANYEVENT_PROTOCOLS" 1322 "PERL_ANYEVENT_PROTOCOLS"
1174 "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to 1339 "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to
1175 resolve or contact IPv6 addresses. 1340 resolve or contact IPv6 addresses.
1176 "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but 1341 "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but
1177 prefer IPv6 over IPv4. 1342 prefer IPv6 over IPv4.
1178 1343
1344 "PERL_ANYEVENT_HOSTS"
1345 This variable, if specified, overrides the /etc/hosts file used by
1346 AnyEvent::Socket"::resolve_sockaddr", i.e. hosts aliases will be
1347 read from that file instead.
1348
1179 "PERL_ANYEVENT_EDNS0" 1349 "PERL_ANYEVENT_EDNS0"
1180 Used by AnyEvent::DNS to decide whether to use the EDNS0 extension 1350 Used by AnyEvent::DNS to decide whether to use the EDNS0 extension
1181 for DNS. This extension is generally useful to reduce DNS traffic, 1351 for DNS. This extension is generally useful to reduce DNS traffic,
1182 but some (broken) firewalls drop such DNS packets, which is why it 1352 especially when DNSSEC is involved, but some (broken) firewalls drop
1183 is off by default. 1353 such DNS packets, which is why it is off by default.
1184 1354
1185 Setting this variable to 1 will cause AnyEvent::DNS to announce 1355 Setting this variable to 1 will cause AnyEvent::DNS to announce
1186 EDNS0 in its DNS requests. 1356 EDNS0 in its DNS requests.
1187 1357
1188 "PERL_ANYEVENT_MAX_FORKS" 1358 "PERL_ANYEVENT_MAX_FORKS"
1192 "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" 1362 "PERL_ANYEVENT_MAX_OUTSTANDING_DNS"
1193 The default value for the "max_outstanding" parameter for the 1363 The default value for the "max_outstanding" parameter for the
1194 default DNS resolver - this is the maximum number of parallel DNS 1364 default DNS resolver - this is the maximum number of parallel DNS
1195 requests that are sent to the DNS server. 1365 requests that are sent to the DNS server.
1196 1366
1367 "PERL_ANYEVENT_MAX_SIGNAL_LATENCY"
1368 Perl has inherently racy signal handling (you can basically choose
1369 between losing signals and memory corruption) - pure perl event
1370 loops (including "AnyEvent::Loop", when "Async::Interrupt" isn't
1371 available) therefore have to poll regularly to avoid losing signals.
1372
1373 Some event loops are racy, but don't poll regularly, and some event
1374 loops are written in C but are still racy. For those event loops,
1375 AnyEvent installs a timer that regularly wakes up the event loop.
1376
1377 By default, the interval for this timer is 10 seconds, but you can
1378 override this delay with this environment variable (or by setting
1379 the $AnyEvent::MAX_SIGNAL_LATENCY variable before creating signal
1380 watchers).
1381
1382 Lower values increase CPU (and energy) usage, higher values can
1383 introduce long delays when reaping children or waiting for signals.
1384
1385 The AnyEvent::Async module, if available, will be used to avoid this
1386 polling (with most event loops).
1387
1197 "PERL_ANYEVENT_RESOLV_CONF" 1388 "PERL_ANYEVENT_RESOLV_CONF"
1198 The file to use instead of /etc/resolv.conf (or OS-specific 1389 The absolute path to a resolv.conf-style file to use instead of
1199 configuration) in the default resolver. When set to the empty 1390 /etc/resolv.conf (or the OS-specific configuration) in the default
1200 string, no default config will be used. 1391 resolver, or the empty string to select the default configuration.
1201 1392
1202 "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". 1393 "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH".
1203 When neither "ca_file" nor "ca_path" was specified during 1394 When neither "ca_file" nor "ca_path" was specified during
1204 AnyEvent::TLS context creation, and either of these environment 1395 AnyEvent::TLS context creation, and either of these environment
1205 variables exist, they will be used to specify CA certificate 1396 variables are nonempty, they will be used to specify CA certificate
1206 locations instead of a system-dependent default. 1397 locations instead of a system-dependent default.
1207 1398
1208 "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" 1399 "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT"
1209 When these are set to 1, then the respective modules are not loaded. 1400 When these are set to 1, then the respective modules are not loaded.
1210 Mostly good for testing AnyEvent itself. 1401 Mostly good for testing AnyEvent itself.
1530 when used without AnyEvent), but most event loops have acceptable 1721 when used without AnyEvent), but most event loops have acceptable
1531 performance with or without AnyEvent. 1722 performance with or without AnyEvent.
1532 1723
1533 * The overhead AnyEvent adds is usually much smaller than the overhead 1724 * The overhead AnyEvent adds is usually much smaller than the overhead
1534 of the actual event loop, only with extremely fast event loops such 1725 of the actual event loop, only with extremely fast event loops such
1535 as EV adds AnyEvent significant overhead. 1726 as EV does AnyEvent add significant overhead.
1536 1727
1537 * You should avoid POE like the plague if you want performance or 1728 * You should avoid POE like the plague if you want performance or
1538 reasonable memory usage. 1729 reasonable memory usage.
1539 1730
1540 BENCHMARKING THE LARGE SERVER CASE 1731 BENCHMARKING THE LARGE SERVER CASE
1738 1929
1739 Feel free to install your own handler, or reset it to defaults. 1930 Feel free to install your own handler, or reset it to defaults.
1740 1931
1741RECOMMENDED/OPTIONAL MODULES 1932RECOMMENDED/OPTIONAL MODULES
1742 One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and 1933 One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
1743 it's built-in modules) are required to use it. 1934 its built-in modules) are required to use it.
1744 1935
1745 That does not mean that AnyEvent won't take advantage of some additional 1936 That does not mean that AnyEvent won't take advantage of some additional
1746 modules if they are installed. 1937 modules if they are installed.
1747 1938
1748 This section explains which additional modules will be used, and how 1939 This section explains which additional modules will be used, and how
1799 worthwhile: If this module is installed, then AnyEvent::Handle (with 1990 worthwhile: If this module is installed, then AnyEvent::Handle (with
1800 the help of AnyEvent::TLS), gains the ability to do TLS/SSL. 1991 the help of AnyEvent::TLS), gains the ability to do TLS/SSL.
1801 1992
1802 Time::HiRes 1993 Time::HiRes
1803 This module is part of perl since release 5.008. It will be used 1994 This module is part of perl since release 5.008. It will be used
1804 when the chosen event library does not come with a timing source on 1995 when the chosen event library does not come with a timing source of
1805 it's own. The pure-perl event loop (AnyEvent::Impl::Perl) will 1996 its own. The pure-perl event loop (AnyEvent::Loop) will additionally
1806 additionally use it to try to use a monotonic clock for timing 1997 load it to try to use a monotonic clock for timing stability.
1807 stability.
1808 1998
1809FORK 1999FORK
1810 Most event libraries are not fork-safe. The ones who are usually are 2000 Most event libraries are not fork-safe. The ones who are usually are
1811 because they rely on inefficient but fork-safe "select" or "poll" calls 2001 because they rely on inefficient but fork-safe "select" or "poll" calls
1812 - higher performance APIs such as BSD's kqueue or the dreaded Linux 2002 - higher performance APIs such as BSD's kqueue or the dreaded Linux
1843 2033
1844 You can make AnyEvent completely ignore this variable by deleting it 2034 You can make AnyEvent completely ignore this variable by deleting it
1845 before the first watcher gets created, e.g. with a "BEGIN" block: 2035 before the first watcher gets created, e.g. with a "BEGIN" block:
1846 2036
1847 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 2037 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1848 2038
1849 use AnyEvent; 2039 use AnyEvent;
1850 2040
1851 Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2041 Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1852 be used to probe what backend is used and gain other information (which 2042 be used to probe what backend is used and gain other information (which
1853 is probably even less useful to an attacker than PERL_ANYEVENT_MODEL), 2043 is probably even less useful to an attacker than PERL_ANYEVENT_MODEL),
1854 and $ENV{PERL_ANYEVENT_STRICT}. 2044 and $ENV{PERL_ANYEVENT_STRICT}.
1863 5.10 and check wether the leaks still show up. (Perl 5.10.0 has other 2053 5.10 and check wether the leaks still show up. (Perl 5.10.0 has other
1864 annoying memleaks, such as leaking on "map" and "grep" but it is usually 2054 annoying memleaks, such as leaking on "map" and "grep" but it is usually
1865 not as pronounced). 2055 not as pronounced).
1866 2056
1867SEE ALSO 2057SEE ALSO
1868 Utility functions: AnyEvent::Util. 2058 Tutorial/Introduction: AnyEvent::Intro.
1869 2059
1870 Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, 2060 FAQ: AnyEvent::FAQ.
1871 Event::Lib, Qt, POE. 2061
2062 Utility functions: AnyEvent::Util (misc. grab-bag), AnyEvent::Log
2063 (simply logging).
2064
2065 Development/Debugging: AnyEvent::Strict (stricter checking),
2066 AnyEvent::Debug (interactive shell, watcher tracing).
2067
2068 Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event,
2069 Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK.
1872 2070
1873 Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, 2071 Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event,
1874 AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, 2072 AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl,
1875 AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, 2073 AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE,
1876 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. 2074 AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK.
1877 2075
1878 Non-blocking file handles, sockets, TCP clients and servers: 2076 Non-blocking handles, pipes, stream sockets, TCP clients and servers:
1879 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. 2077 AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS.
1880 2078
1881 Asynchronous DNS: AnyEvent::DNS. 2079 Asynchronous DNS: AnyEvent::DNS.
1882 2080
1883 Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event, 2081 Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event.
1884 2082
1885 Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::XMPP, 2083 Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC,
1886 AnyEvent::HTTP. 2084 AnyEvent::HTTP.
1887 2085
1888AUTHOR 2086AUTHOR
1889 Marc Lehmann <schmorp@schmorp.de> 2087 Marc Lehmann <schmorp@schmorp.de>
1890 http://home.schmorp.de/ 2088 http://home.schmorp.de/

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