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15 # file handle or descriptor readable 15 # file handle or descriptor readable
16 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); 16 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
17 17
18 # one-shot or repeating timers 18 # one-shot or repeating timers
19 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); 19 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
20 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... 20 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
21 21
22 print AnyEvent->now; # prints current event loop time 22 print AnyEvent->now; # prints current event loop time
23 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. 23 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
24 24
25 # POSIX signal 25 # POSIX signal
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46in a tutorial or some gentle introduction, have a look at the 46in a tutorial or some gentle introduction, have a look at the
47L<AnyEvent::Intro> manpage. 47L<AnyEvent::Intro> manpage.
48 48
49=head1 SUPPORT 49=head1 SUPPORT
50 50
51An FAQ document is available as L<AnyEvent::FAQ>.
52
51There is a mailinglist for discussing all things AnyEvent, and an IRC 53There also is a mailinglist for discussing all things AnyEvent, and an IRC
52channel, too. 54channel, too.
53 55
54See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software 56See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
55Repository>, at L<http://anyevent.schmorp.de>, for more info. 57Repository>, at L<http://anyevent.schmorp.de>, for more info.
56 58
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76module 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
77model you use. 79model you use.
78 80
79For 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
80actually 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
81like 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
82cannot use anything else, as they are simply incompatible to everything 84cannot use anything else, as they are simply incompatible to everything
83that 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
84module 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.
85 87
86AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 88AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
87fine. 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
88with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if 90with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
89your module uses one of those, every user of your module has to use it, 91your module uses one of those, every user of your module has to use it,
90too. But if your module uses AnyEvent, it works transparently with all 92too. But if your module uses AnyEvent, it works transparently with all
91event models it supports (including stuff like IO::Async, as long as those 93event models it supports (including stuff like IO::Async, as long as those
92use one of the supported event loops. It is trivial to add new event loops 94use one of the supported event loops. It is easy to add new event loops
93to AnyEvent, too, so it is future-proof). 95to AnyEvent, too, so it is future-proof).
94 96
95In 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
96model>, 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
97modules, 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
98follow. 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
99offering 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
100technically possible. 102technically possible.
101 103
102Of course, AnyEvent comes with a big (and fully optional!) toolbox 104Of course, AnyEvent comes with a big (and fully optional!) toolbox
103of useful functionality, such as an asynchronous DNS resolver, 100% 105of useful functionality, such as an asynchronous DNS resolver, 100%
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109useful) 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
110model, you should I<not> use this module. 112model, you should I<not> use this module.
111 113
112=head1 DESCRIPTION 114=head1 DESCRIPTION
113 115
114L<AnyEvent> provides an identical interface to multiple event loops. This 116L<AnyEvent> provides a uniform interface to various event loops. This
115allows module authors to utilise an event loop without forcing module 117allows module authors to use event loop functionality without forcing
116users 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
117peacefully at any one time). 119than one event loop cannot coexist peacefully).
118 120
119The 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>
120module. 122module.
121 123
122During the first call of any watcher-creation method, the module tries 124During the first call of any watcher-creation method, the module tries
123to 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
124following modules is already loaded: L<EV>, 126following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
125L<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
126L<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
127to 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
128adaptor should always succeed) in the order given. The first one that can 130available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
129be successfully loaded will be used. If, after this, still none could be 131the other two are not normally tried.
130found, AnyEvent will fall back to a pure-perl event loop, which is not
131very efficient, but should work everywhere.
132 132
133Because AnyEvent first checks for modules that are already loaded, loading 133Because AnyEvent first checks for modules that are already loaded, loading
134an event model explicitly before first using AnyEvent will likely make 134an event model explicitly before first using AnyEvent will likely make
135that model the default. For example: 135that model the default. For example:
136 136
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138 use AnyEvent; 138 use AnyEvent;
139 139
140 # .. AnyEvent will likely default to Tk 140 # .. AnyEvent will likely default to Tk
141 141
142The 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
143starts 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,
144use AnyEvent so their modules work together with others seamlessly... 144as very few modules hardcode event loops without announcing this very
145loudly.
145 146
146The pure-perl implementation of AnyEvent is called 147The pure-perl implementation of AnyEvent is called
147C<AnyEvent::Impl::Perl>. Like other event modules you can load it 148C<AnyEvent::Impl::Perl>. Like other event modules you can load it
148explicitly and enjoy the high availability of that event loop :) 149explicitly and enjoy the high availability of that event loop :)
149 150
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158callback when the event occurs (of course, only when the event model 159callback when the event occurs (of course, only when the event model
159is in control). 160is in control).
160 161
161Note that B<callbacks must not permanently change global variables> 162Note that B<callbacks must not permanently change global variables>
162potentially 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<<
163callbacks must not C<die> >>. The former is good programming practise in 164callbacks must not C<die> >>. The former is good programming practice in
164Perl and the latter stems from the fact that exception handling differs 165Perl and the latter stems from the fact that exception handling differs
165widely between event loops. 166widely between event loops.
166 167
167To 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
168variable 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
169to it). 170to it).
170 171
171All 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.
172 173
173Many watchers either are used with "recursion" (repeating timers for 174Many watchers either are used with "recursion" (repeating timers for
174example), or need to refer to their watcher object in other ways. 175example), or need to refer to their watcher object in other ways.
175 176
176An any way to achieve that is this pattern: 177One way to achieve that is this pattern:
177 178
178 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 179 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
179 # you can use $w here, for example to undef it 180 # you can use $w here, for example to undef it
180 undef $w; 181 undef $w;
181 }); 182 });
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213 214
214The 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.
215You 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
216underlying file descriptor. 217underlying file descriptor.
217 218
218Some event loops issue spurious readyness notifications, so you should 219Some event loops issue spurious readiness notifications, so you should
219always use non-blocking calls when reading/writing from/to your file 220always use non-blocking calls when reading/writing from/to your file
220handles. 221handles.
221 222
222Example: 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
223watcher. 224watcher.
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247 248
248Although the callback might get passed parameters, their value and 249Although the callback might get passed parameters, their value and
249presence is undefined and you cannot rely on them. Portable AnyEvent 250presence is undefined and you cannot rely on them. Portable AnyEvent
250callbacks cannot use arguments passed to time watcher callbacks. 251callbacks cannot use arguments passed to time watcher callbacks.
251 252
252The callback will normally be invoked once only. If you specify another 253The callback will normally be invoked only once. If you specify another
253parameter, C<interval>, as a strictly positive number (> 0), then the 254parameter, C<interval>, as a strictly positive number (> 0), then the
254callback will be invoked regularly at that interval (in fractional 255callback will be invoked regularly at that interval (in fractional
255seconds) after the first invocation. If C<interval> is specified with a 256seconds) after the first invocation. If C<interval> is specified with a
256false value, then it is treated as if it were missing. 257false value, then it is treated as if it were not specified at all.
257 258
258The callback will be rescheduled before invoking the callback, but no 259The callback will be rescheduled before invoking the callback, but no
259attempt 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
260only approximate. 261only approximate.
261 262
262Example: fire an event after 7.7 seconds. 263Example: fire an event after 7.7 seconds.
263 264
264 my $w = AnyEvent->timer (after => 7.7, cb => sub { 265 my $w = AnyEvent->timer (after => 7.7, cb => sub {
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282 283
283While 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
284use absolute time internally. This makes a difference when your clock 285use absolute time internally. This makes a difference when your clock
285"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
286the 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
287fire "after" a second might actually take six years to finally fire. 288fire "after a second" might actually take six years to finally fire.
288 289
289AnyEvent cannot compensate for this. The only event loop that is conscious 290AnyEvent cannot compensate for this. The only event loop that is conscious
290about 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
291on true relative time) and absolute (ev_periodic, based on wallclock time) 292on true relative time) and absolute (ev_periodic, based on wallclock time)
292timers. 293timers.
293 294
294AnyEvent always prefers relative timers, if available, matching the 295AnyEvent always prefers relative timers, if available, matching the
295AnyEvent API. 296AnyEvent API.
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317I<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
318function to call when you want to know the current time.> 319function to call when you want to know the current time.>
319 320
320This function is also often faster then C<< AnyEvent->time >>, and 321This function is also often faster then C<< AnyEvent->time >>, and
321thus the preferred method if you want some timestamp (for example, 322thus the preferred method if you want some timestamp (for example,
322L<AnyEvent::Handle> uses this to update it's activity timeouts). 323L<AnyEvent::Handle> uses this to update its activity timeouts).
323 324
324The 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
325with your timing, you can skip it without bad conscience. 326with your timing; you can skip it without a bad conscience.
326 327
327For 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>
328and L<EV> and the following set-up: 329and L<EV> and the following set-up:
329 330
330The 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
331time=500 (assume no other callbacks delay processing). In your callback, 332time=500 (assume no other callbacks delay processing). In your callback,
332you 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
333second) 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
334after three seconds. 335after three seconds.
335 336
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428=head3 Signal Races, Delays and Workarounds 429=head3 Signal Races, Delays and Workarounds
429 430
430Many 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
431callbacks 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
432do race-free signal handling in perl, requiring C libraries for 433do race-free signal handling in perl, requiring C libraries for
433this. 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,
434signals 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
435specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This 436specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
436variable can be changed only before the first signal watcher is created, 437variable can be changed only before the first signal watcher is created,
437and should be left alone otherwise. This variable determines how often 438and should be left alone otherwise. This variable determines how often
438AnyEvent 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
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440saving. 441saving.
441 442
442All these problems can be avoided by installing the optional 443All these problems can be avoided by installing the optional
443L<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
444work 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>
445(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
446one-second latency). For those, you just have to suffer the delays. 447one-second latency). For those, you just have to suffer the delays.
447 448
448=head2 CHILD PROCESS WATCHERS 449=head2 CHILD PROCESS WATCHERS
449 450
450 $w = AnyEvent->child (pid => <process id>, cb => <callback>); 451 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
451 452
452You 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.
453 454
454The 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,
455using 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
456croak). The watcher will be triggered only when the child process has 457croak). The watcher will be triggered only when the child process has
457finished and an exit status is available, not on any trace events 458finished and an exit status is available, not on any trace events
458(stopped/continued). 459(stopped/continued).
459 460
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506 507
507=head2 IDLE WATCHERS 508=head2 IDLE WATCHERS
508 509
509 $w = AnyEvent->idle (cb => <callback>); 510 $w = AnyEvent->idle (cb => <callback>);
510 511
511Repeatedly invoke the callback after the process becomes idle, until 512This will repeatedly invoke the callback after the process becomes idle,
512either the watcher is destroyed or new events have been detected. 513until either the watcher is destroyed or new events have been detected.
513 514
514Idle watchers are useful when there is a need to do something, but it 515Idle watchers are useful when there is a need to do something, but it
515is not so important (or wise) to do it instantly. The callback will be 516is not so important (or wise) to do it instantly. The callback will be
516invoked only when there is "nothing better to do", which is usually 517invoked only when there is "nothing better to do", which is usually
517defined as "all outstanding events have been handled and no new events 518defined as "all outstanding events have been handled and no new events
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556will actively watch for new events and call your callbacks. 557will actively watch for new events and call your callbacks.
557 558
558AnyEvent is slightly different: it expects somebody else to run the event 559AnyEvent is slightly different: it expects somebody else to run the event
559loop 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).
560 561
561The instrument to do that is called a "condition variable", so called 562The tool to do that is called a "condition variable", so called because
562because they represent a condition that must become true. 563they represent a condition that must become true.
563 564
564Now 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.
565 566
566Condition variables can be created by calling the C<< AnyEvent->condvar 567Condition variables can be created by calling the C<< AnyEvent->condvar
567>> method, usually without arguments. The only argument pair allowed is 568>> method, usually without arguments. The only argument pair allowed is
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572After creation, the condition variable is "false" until it becomes "true" 573After creation, the condition variable is "false" until it becomes "true"
573by 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
574were 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<<
575->send >> method). 576->send >> method).
576 577
577Condition variables are similar to callbacks, except that you can 578Since condition variables are the most complex part of the AnyEvent API, here are
578optionally 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:
579in time where multiple outstanding events have been processed. And yet 580
580another way to call them is transactions - each condition variable can be 581=over 4
581used to represent a transaction, which finishes at some point and delivers 582
582a 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
583compute/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
584 601
585Condition variables are very useful to signal that something has finished, 602Condition variables are very useful to signal that something has finished,
586for example, if you write a module that does asynchronous http requests, 603for example, if you write a module that does asynchronous http requests,
587then a condition variable would be the ideal candidate to signal the 604then a condition variable would be the ideal candidate to signal the
588availability of results. The user can either act when the callback is 605availability of results. The user can either act when the callback is
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601 618
602Condition variables are represented by hash refs in perl, and the keys 619Condition variables are represented by hash refs in perl, and the keys
603used 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
604easy (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
605AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call 622AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
606it's C<new> method in your own C<new> method. 623its C<new> method in your own C<new> method.
607 624
608There are two "sides" to a condition variable - the "producer side" which 625There are two "sides" to a condition variable - the "producer side" which
609eventually calls C<< -> send >>, and the "consumer side", which waits 626eventually calls C<< -> send >>, and the "consumer side", which waits
610for the send to occur. 627for the send to occur.
611 628
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676they 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
677C<send>. 694C<send>.
678 695
679=item $cv->croak ($error) 696=item $cv->croak ($error)
680 697
681Similar to send, but causes all call's to C<< ->recv >> to invoke 698Similar to send, but causes all calls to C<< ->recv >> to invoke
682C<Carp::croak> with the given error message/object/scalar. 699C<Carp::croak> with the given error message/object/scalar.
683 700
684This can be used to signal any errors to the condition variable 701This can be used to signal any errors to the condition variable
685user/consumer. Doing it this way instead of calling C<croak> directly 702user/consumer. Doing it this way instead of calling C<croak> directly
686delays the error detetcion, but has the overwhelmign advantage that it 703delays the error detection, but has the overwhelming advantage that it
687diagnoses 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
688deep in some event clalback without connection to the actual code causing 705deep in some event callback with no connection to the actual code causing
689the problem. 706the problem.
690 707
691=item $cv->begin ([group callback]) 708=item $cv->begin ([group callback])
692 709
693=item $cv->end 710=item $cv->end
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731one 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
732sending. 749sending.
733 750
734The ping example mentioned above is slightly more complicated, as the 751The ping example mentioned above is slightly more complicated, as the
735there 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
736begung can potentially be zero: 753begun can potentially be zero:
737 754
738 my $cv = AnyEvent->condvar; 755 my $cv = AnyEvent->condvar;
739 756
740 my %result; 757 my %result;
741 $cv->begin (sub { shift->send (\%result) }); 758 $cv->begin (sub { shift->send (\%result) });
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762to 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
763C<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
764doesn't execute once). 781doesn't execute once).
765 782
766This is the general pattern when you "fan out" into multiple (but 783This is the general pattern when you "fan out" into multiple (but
767potentially 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
768the 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
769subrequest you start, call C<begin> and for each subrequest you finish, 786subrequest you start, call C<begin> and for each subrequest you finish,
770call C<end>. 787call C<end>.
771 788
772=back 789=back
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779=over 4 796=over 4
780 797
781=item $cv->recv 798=item $cv->recv
782 799
783Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 800Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
784>> methods have been called on c<$cv>, while servicing other watchers 801>> methods have been called on C<$cv>, while servicing other watchers
785normally. 802normally.
786 803
787You 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
788will return immediately. 805will return immediately.
789 806
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806caller 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
807condition variables with some kind of request results and supporting 824condition variables with some kind of request results and supporting
808callbacks so the caller knows that getting the result will not block, 825callbacks so the caller knows that getting the result will not block,
809while still supporting blocking waits if the caller so desires). 826while still supporting blocking waits if the caller so desires).
810 827
811You 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
812only calling C<< ->recv >> from within that callback (or at a later 829only calling C<< ->recv >> from within that callback (or at a later
813time). 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
814waits otherwise. 831waits otherwise.
815 832
816=item $bool = $cv->ready 833=item $bool = $cv->ready
… …
821=item $cb = $cv->cb ($cb->($cv)) 838=item $cb = $cv->cb ($cb->($cv))
822 839
823This is a mutator function that returns the callback set and optionally 840This is a mutator function that returns the callback set and optionally
824replaces it before doing so. 841replaces it before doing so.
825 842
826The callback will be called when the condition becomes (or already was) 843The callback will be called when the condition becomes "true", i.e. when
827"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
828the 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
829inside the callback or at any later time is guaranteed not to block. 847the callback or at any later time is guaranteed not to block.
830 848
831=back 849=back
832 850
833=head1 SUPPORTED EVENT LOOPS/BACKENDS 851=head1 SUPPORTED EVENT LOOPS/BACKENDS
834 852
… …
846 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 864 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
847 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 865 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
848 866
849=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.
850 868
851These 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
852is 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
853them. This means that AnyEvent will automatically pick the right backend 871them. This means that AnyEvent will automatically pick the right backend
854when the main program loads an event module before anything starts to 872when the main program loads an event module before anything starts to
855create watchers. Nothing special needs to be done by the main program. 873create watchers. Nothing special needs to be done by the main program.
856 874
… …
872 890
873Support for IO::Async can only be partial, as it is too broken and 891Support for IO::Async can only be partial, as it is too broken and
874architecturally limited to even support the AnyEvent API. It also 892architecturally limited to even support the AnyEvent API. It also
875is the only event loop that needs the loop to be set explicitly, so 893is the only event loop that needs the loop to be set explicitly, so
876it can only be used by a main program knowing about AnyEvent. See 894it can only be used by a main program knowing about AnyEvent. See
877L<AnyEvent::Impl::Async> for the gory details. 895L<AnyEvent::Impl::IOAsync> for the gory details.
878 896
879 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed. 897 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
880 898
881=item Event loops that are indirectly supported via other backends. 899=item Event loops that are indirectly supported via other backends.
882 900
… …
910Contains C<undef> until the first watcher is being created, before the 928Contains C<undef> until the first watcher is being created, before the
911backend has been autodetected. 929backend has been autodetected.
912 930
913Afterwards it contains the event model that is being used, which is the 931Afterwards it contains the event model that is being used, which is the
914name of the Perl class implementing the model. This class is usually one 932name of the Perl class implementing the model. This class is usually one
915of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the 933of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
916case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it 934case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
917will be C<urxvt::anyevent>). 935will be C<urxvt::anyevent>).
918 936
919=item AnyEvent::detect 937=item AnyEvent::detect
920 938
921Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 939Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
922if necessary. You should only call this function right before you would 940if necessary. You should only call this function right before you would
923have created an AnyEvent watcher anyway, that is, as late as possible at 941have created an AnyEvent watcher anyway, that is, as late as possible at
924runtime, and not e.g. while initialising of your module. 942runtime, and not e.g. during initialisation of your module.
925 943
926If you need to do some initialisation before AnyEvent watchers are 944If you need to do some initialisation before AnyEvent watchers are
927created, use C<post_detect>. 945created, use C<post_detect>.
928 946
929=item $guard = AnyEvent::post_detect { BLOCK } 947=item $guard = AnyEvent::post_detect { BLOCK }
930 948
931Arranges for the code block to be executed as soon as the event model is 949Arranges for the code block to be executed as soon as the event model is
932autodetected (or immediately if this has already happened). 950autodetected (or immediately if that has already happened).
933 951
934The block will be executed I<after> the actual backend has been detected 952The block will be executed I<after> the actual backend has been detected
935(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been 953(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
936created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do 954created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
937other initialisations - see the sources of L<AnyEvent::Strict> or 955other initialisations - see the sources of L<AnyEvent::Strict> or
… …
946that automatically removes the callback again when it is destroyed (or 964that automatically removes the callback again when it is destroyed (or
947C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for 965C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
948a case where this is useful. 966a case where this is useful.
949 967
950Example: Create a watcher for the IO::AIO module and store it in 968Example: Create a watcher for the IO::AIO module and store it in
951C<$WATCHER>. Only do so after the event loop is initialised, though. 969C<$WATCHER>, but do so only do so after the event loop is initialised.
952 970
953 our WATCHER; 971 our WATCHER;
954 972
955 my $guard = AnyEvent::post_detect { 973 my $guard = AnyEvent::post_detect {
956 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); 974 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
… …
964 $WATCHER ||= $guard; 982 $WATCHER ||= $guard;
965 983
966=item @AnyEvent::post_detect 984=item @AnyEvent::post_detect
967 985
968If there are any code references in this array (you can C<push> to it 986If there are any code references in this array (you can C<push> to it
969before or after loading AnyEvent), then they will called directly after 987before or after loading AnyEvent), then they will be called directly
970the event loop has been chosen. 988after the event loop has been chosen.
971 989
972You should check C<$AnyEvent::MODEL> before adding to this array, though: 990You should check C<$AnyEvent::MODEL> before adding to this array, though:
973if it is defined then the event loop has already been detected, and the 991if it is defined then the event loop has already been detected, and the
974array will be ignored. 992array will be ignored.
975 993
… …
1011because it will stall the whole program, and the whole point of using 1029because it will stall the whole program, and the whole point of using
1012events is to stay interactive. 1030events is to stay interactive.
1013 1031
1014It is fine, however, to call C<< ->recv >> when the user of your module 1032It is fine, however, to call C<< ->recv >> when the user of your module
1015requests it (i.e. if you create a http request object ad have a method 1033requests it (i.e. if you create a http request object ad have a method
1016called C<results> that returns the results, it should call C<< ->recv >> 1034called C<results> that returns the results, it may call C<< ->recv >>
1017freely, as the user of your module knows what she is doing. always). 1035freely, as the user of your module knows what she is doing. Always).
1018 1036
1019=head1 WHAT TO DO IN THE MAIN PROGRAM 1037=head1 WHAT TO DO IN THE MAIN PROGRAM
1020 1038
1021There will always be a single main program - the only place that should 1039There will always be a single main program - the only place that should
1022dictate which event model to use. 1040dictate which event model to use.
1023 1041
1024If it doesn't care, it can just "use AnyEvent" and use it itself, or not 1042If the program is not event-based, it need not do anything special, even
1025do anything special (it does not need to be event-based) and let AnyEvent 1043when it depends on a module that uses an AnyEvent. If the program itself
1026decide which implementation to chose if some module relies on it. 1044uses AnyEvent, but does not care which event loop is used, all it needs
1045to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
1046available loop implementation.
1027 1047
1028If the main program relies on a specific event model - for example, in 1048If the main program relies on a specific event model - for example, in
1029Gtk2 programs you have to rely on the Glib module - you should load the 1049Gtk2 programs you have to rely on the Glib module - you should load the
1030event module before loading AnyEvent or any module that uses it: generally 1050event module before loading AnyEvent or any module that uses it: generally
1031speaking, you should load it as early as possible. The reason is that 1051speaking, you should load it as early as possible. The reason is that
1032modules might create watchers when they are loaded, and AnyEvent will 1052modules might create watchers when they are loaded, and AnyEvent will
1033decide on the event model to use as soon as it creates watchers, and it 1053decide on the event model to use as soon as it creates watchers, and it
1034might chose the wrong one unless you load the correct one yourself. 1054might choose the wrong one unless you load the correct one yourself.
1035 1055
1036You can chose to use a pure-perl implementation by loading the 1056You can chose to use a pure-perl implementation by loading the
1037C<AnyEvent::Impl::Perl> module, which gives you similar behaviour 1057C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
1038everywhere, but letting AnyEvent chose the model is generally better. 1058everywhere, but letting AnyEvent chose the model is generally better.
1039 1059
… …
1057=head1 OTHER MODULES 1077=head1 OTHER MODULES
1058 1078
1059The following is a non-exhaustive list of additional modules that use 1079The following is a non-exhaustive list of additional modules that use
1060AnyEvent as a client and can therefore be mixed easily with other AnyEvent 1080AnyEvent as a client and can therefore be mixed easily with other AnyEvent
1061modules and other event loops in the same program. Some of the modules 1081modules and other event loops in the same program. Some of the modules
1062come with AnyEvent, the others are available via CPAN. 1082come as part of AnyEvent, the others are available via CPAN.
1063 1083
1064=over 4 1084=over 4
1065 1085
1066=item L<AnyEvent::Util> 1086=item L<AnyEvent::Util>
1067 1087
1068Contains various utility functions that replace often-used but blocking 1088Contains various utility functions that replace often-used blocking
1069functions such as C<inet_aton> by event-/callback-based versions. 1089functions such as C<inet_aton> with event/callback-based versions.
1070 1090
1071=item L<AnyEvent::Socket> 1091=item L<AnyEvent::Socket>
1072 1092
1073Provides various utility functions for (internet protocol) sockets, 1093Provides various utility functions for (internet protocol) sockets,
1074addresses and name resolution. Also functions to create non-blocking tcp 1094addresses and name resolution. Also functions to create non-blocking tcp
… …
1076 1096
1077=item L<AnyEvent::Handle> 1097=item L<AnyEvent::Handle>
1078 1098
1079Provide read and write buffers, manages watchers for reads and writes, 1099Provide read and write buffers, manages watchers for reads and writes,
1080supports raw and formatted I/O, I/O queued and fully transparent and 1100supports raw and formatted I/O, I/O queued and fully transparent and
1081non-blocking SSL/TLS (via L<AnyEvent::TLS>. 1101non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1082 1102
1083=item L<AnyEvent::DNS> 1103=item L<AnyEvent::DNS>
1084 1104
1085Provides rich asynchronous DNS resolver capabilities. 1105Provides rich asynchronous DNS resolver capabilities.
1086 1106
… …
1094 1114
1095Here be danger! 1115Here be danger!
1096 1116
1097As Pauli would put it, "Not only is it not right, it's not even wrong!" - 1117As Pauli would put it, "Not only is it not right, it's not even wrong!" -
1098there are so many things wrong with AnyEvent::Handle::UDP, most notably 1118there are so many things wrong with AnyEvent::Handle::UDP, most notably
1099it's use of a stream-based API with a protocol that isn't streamable, that 1119its use of a stream-based API with a protocol that isn't streamable, that
1100the only way to improve it is to delete it. 1120the only way to improve it is to delete it.
1101 1121
1102It features data corruption (but typically only under load) and general 1122It features data corruption (but typically only under load) and general
1103confusion. On top, the author is not only clueless about UDP but also 1123confusion. On top, the author is not only clueless about UDP but also
1104fact-resistant - some gems of his understanding: "connect doesn't work 1124fact-resistant - some gems of his understanding: "connect doesn't work
… …
1108wrong with his module when it is explained to him. 1128wrong with his module when it is explained to him.
1109 1129
1110=item L<AnyEvent::DBI> 1130=item L<AnyEvent::DBI>
1111 1131
1112Executes L<DBI> requests asynchronously in a proxy process for you, 1132Executes L<DBI> requests asynchronously in a proxy process for you,
1113notifying you in an event-bnased way when the operation is finished. 1133notifying you in an event-based way when the operation is finished.
1114 1134
1115=item L<AnyEvent::AIO> 1135=item L<AnyEvent::AIO>
1116 1136
1117Truly asynchronous (as opposed to non-blocking) I/O, should be in the 1137Truly asynchronous (as opposed to non-blocking) I/O, should be in the
1118toolbox of every event programmer. AnyEvent::AIO transparently fuses 1138toolbox of every event programmer. AnyEvent::AIO transparently fuses
… …
1137 1157
1138package AnyEvent; 1158package AnyEvent;
1139 1159
1140# basically a tuned-down version of common::sense 1160# basically a tuned-down version of common::sense
1141sub common_sense { 1161sub common_sense {
1142 # from common:.sense 1.0 1162 # from common:.sense 3.3
1143 ${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00"; 1163 ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf3\x0f\xc0\xf0\xfc\x33\x00";
1144 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl) 1164 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1145 $^H |= 0x00000600; 1165 $^H |= 0x00000600;
1146} 1166}
1147 1167
1148BEGIN { AnyEvent::common_sense } 1168BEGIN { AnyEvent::common_sense }
1149 1169
1150use Carp (); 1170use Carp ();
1151 1171
1152our $VERSION = '5.261'; 1172our $VERSION = '5.29';
1153our $MODEL; 1173our $MODEL;
1154 1174
1155our $AUTOLOAD; 1175our $AUTOLOAD;
1156our @ISA; 1176our @ISA;
1157 1177
… …
1271 last; 1291 last;
1272 } 1292 }
1273 } 1293 }
1274 1294
1275 $MODEL 1295 $MODEL
1276 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; 1296 or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1277 } 1297 }
1278 } 1298 }
1279 1299
1280 @models = (); # free probe data 1300 @models = (); # free probe data
1281 1301
1282 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1302 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1283 unshift @ISA, $MODEL; 1303 unshift @ISA, $MODEL;
1284 1304
1285 # now nuke some methods that are overriden by the backend. 1305 # now nuke some methods that are overridden by the backend.
1286 # SUPER is not allowed. 1306 # SUPER is not allowed.
1287 for (qw(time signal child idle)) { 1307 for (qw(time signal child idle)) {
1288 undef &{"AnyEvent::Base::$_"} 1308 undef &{"AnyEvent::Base::$_"}
1289 if defined &{"$MODEL\::$_"}; 1309 if defined &{"$MODEL\::$_"};
1290 } 1310 }
… …
1707 1727
1708package AnyEvent::CondVar; 1728package AnyEvent::CondVar;
1709 1729
1710our @ISA = AnyEvent::CondVar::Base::; 1730our @ISA = AnyEvent::CondVar::Base::;
1711 1731
1732# only to be used for subclassing
1733sub new {
1734 my $class = shift;
1735 bless AnyEvent->condvar (@_), $class
1736}
1737
1712package AnyEvent::CondVar::Base; 1738package AnyEvent::CondVar::Base;
1713 1739
1714#use overload 1740#use overload
1715# '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1741# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1716# fallback => 1; 1742# fallback => 1;
… …
1837check the arguments passed to most method calls. If it finds any problems, 1863check the arguments passed to most method calls. If it finds any problems,
1838it will croak. 1864it will croak.
1839 1865
1840In other words, enables "strict" mode. 1866In other words, enables "strict" mode.
1841 1867
1842Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense> 1868Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1843>>, it is definitely recommended to keep it off in production. Keeping 1869>>, it is definitely recommended to keep it off in production. Keeping
1844C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs 1870C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1845can be very useful, however. 1871can be very useful, however.
1846 1872
1847=item C<PERL_ANYEVENT_MODEL> 1873=item C<PERL_ANYEVENT_MODEL>
… …
2493 unless defined $SIG{PIPE}; 2519 unless defined $SIG{PIPE};
2494 2520
2495=head1 RECOMMENDED/OPTIONAL MODULES 2521=head1 RECOMMENDED/OPTIONAL MODULES
2496 2522
2497One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and 2523One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2498it's built-in modules) are required to use it. 2524its built-in modules) are required to use it.
2499 2525
2500That does not mean that AnyEvent won't take advantage of some additional 2526That does not mean that AnyEvent won't take advantage of some additional
2501modules if they are installed. 2527modules if they are installed.
2502 2528
2503This section explains which additional modules will be used, and how they 2529This section explains which additional modules will be used, and how they
… …
2561the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL. 2587the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2562 2588
2563=item L<Time::HiRes> 2589=item L<Time::HiRes>
2564 2590
2565This module is part of perl since release 5.008. It will be used when the 2591This module is part of perl since release 5.008. It will be used when the
2566chosen event library does not come with a timing source on it's own. The 2592chosen event library does not come with a timing source of its own. The
2567pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to 2593pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2568try to use a monotonic clock for timing stability. 2594try to use a monotonic clock for timing stability.
2569 2595
2570=back 2596=back
2571 2597
… …
2634pronounced). 2660pronounced).
2635 2661
2636 2662
2637=head1 SEE ALSO 2663=head1 SEE ALSO
2638 2664
2665Tutorial/Introduction: L<AnyEvent::Intro>.
2666
2667FAQ: L<AnyEvent::FAQ>.
2668
2639Utility functions: L<AnyEvent::Util>. 2669Utility functions: L<AnyEvent::Util>.
2640 2670
2641Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 2671Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
2642L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2672L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2643 2673
… …
2649Non-blocking file handles, sockets, TCP clients and 2679Non-blocking file handles, sockets, TCP clients and
2650servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 2680servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2651 2681
2652Asynchronous DNS: L<AnyEvent::DNS>. 2682Asynchronous DNS: L<AnyEvent::DNS>.
2653 2683
2654Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, 2684Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2655L<Coro::Event>,
2656 2685
2657Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>, 2686Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2658L<AnyEvent::HTTP>. 2687L<AnyEvent::HTTP>.
2659 2688
2660 2689
2661=head1 AUTHOR 2690=head1 AUTHOR
2662 2691

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