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1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported 5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6event loops. 6FLTK and POE are various supported event loops/environments.
7 7
8=head1 SYNOPSIS 8=head1 SYNOPSIS
9 9
10 use AnyEvent; 10 use AnyEvent;
11 11
12 # if you prefer function calls, look at the AE manpage for
13 # an alternative API.
14
12 # file descriptor readable 15 # file handle or descriptor readable
13 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); 16 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14 17
15 # one-shot or repeating timers 18 # one-shot or repeating timers
16 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); 19 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... 20 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18 21
19 print AnyEvent->now; # prints current event loop time 22 print AnyEvent->now; # prints current event loop time
20 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. 23 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21 24
22 # POSIX signal 25 # POSIX signal
40=head1 INTRODUCTION/TUTORIAL 43=head1 INTRODUCTION/TUTORIAL
41 44
42This manpage is mainly a reference manual. If you are interested 45This manpage is mainly a reference manual. If you are interested
43in a tutorial or some gentle introduction, have a look at the 46in a tutorial or some gentle introduction, have a look at the
44L<AnyEvent::Intro> manpage. 47L<AnyEvent::Intro> manpage.
48
49=head1 SUPPORT
50
51An FAQ document is available as L<AnyEvent::FAQ>.
52
53There also is a mailinglist for discussing all things AnyEvent, and an IRC
54channel, too.
55
56See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
57Repository>, at L<http://anyevent.schmorp.de>, for more info.
45 58
46=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 59=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47 60
48Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 61Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49nowadays. So what is different about AnyEvent? 62nowadays. So what is different about AnyEvent?
65module 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
66model you use. 79model you use.
67 80
68For 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
69actually 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
70like 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
71cannot use anything else, as they are simply incompatible to everything 84cannot use anything else, as they are simply incompatible to everything
72that 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
73module 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.
74 87
75AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 88AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76fine. 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
77with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if 90with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78your module uses one of those, every user of your module has to use it, 91uses one of those, every user of your module has to use it, too. But if
79too. But if your module uses AnyEvent, it works transparently with all 92your module uses AnyEvent, it works transparently with all event models it
80event models it supports (including stuff like IO::Async, as long as those 93supports (including stuff like IO::Async, as long as those use one of the
81use one of the supported event loops. It is trivial to add new event loops 94supported event loops. It is easy to add new event loops to AnyEvent, too,
82to AnyEvent, too, so it is future-proof). 95so it is future-proof).
83 96
84In 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
85model>, 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
86modules, 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
87follow. 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
88offering 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
89technically possible. 102technically possible.
90 103
91Of course, AnyEvent comes with a big (and fully optional!) toolbox 104Of course, AnyEvent comes with a big (and fully optional!) toolbox
92of useful functionality, such as an asynchronous DNS resolver, 100% 105of useful functionality, such as an asynchronous DNS resolver, 100%
98useful) 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
99model, you should I<not> use this module. 112model, you should I<not> use this module.
100 113
101=head1 DESCRIPTION 114=head1 DESCRIPTION
102 115
103L<AnyEvent> provides an identical interface to multiple event loops. This 116L<AnyEvent> provides a uniform interface to various event loops. This
104allows module authors to utilise an event loop without forcing module 117allows module authors to use event loop functionality without forcing
105users 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
106peacefully at any one time). 119than one event loop cannot coexist peacefully).
107 120
108The 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>
109module. 122module.
110 123
111During the first call of any watcher-creation method, the module tries 124During the first call of any watcher-creation method, the module tries
112to 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
113following modules is already loaded: L<EV>, 126following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114L<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
115L<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
116to 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
117adaptor should always succeed) in the order given. The first one that can 130available, the pure-perl L<AnyEvent::Loop> should always work, so
118be successfully loaded will be used. If, after this, still none could be 131the other two are not normally tried.
119found, AnyEvent will fall back to a pure-perl event loop, which is not
120very efficient, but should work everywhere.
121 132
122Because AnyEvent first checks for modules that are already loaded, loading 133Because AnyEvent first checks for modules that are already loaded, loading
123an event model explicitly before first using AnyEvent will likely make 134an event model explicitly before first using AnyEvent will likely make
124that model the default. For example: 135that model the default. For example:
125 136
127 use AnyEvent; 138 use AnyEvent;
128 139
129 # .. AnyEvent will likely default to Tk 140 # .. AnyEvent will likely default to Tk
130 141
131The 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
132starts 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,
133use AnyEvent so their modules work together with others seamlessly... 144as very few modules hardcode event loops without announcing this very
145loudly.
134 146
135The pure-perl implementation of AnyEvent is called 147The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136C<AnyEvent::Impl::Perl>. Like other event modules you can load it 148other event modules you can load it explicitly and enjoy the high
137explicitly and enjoy the high availability of that event loop :) 149availability of that event loop :)
138 150
139=head1 WATCHERS 151=head1 WATCHERS
140 152
141AnyEvent has the central concept of a I<watcher>, which is an object that 153AnyEvent has the central concept of a I<watcher>, which is an object that
142stores relevant data for each kind of event you are waiting for, such as 154stores relevant data for each kind of event you are waiting for, such as
147callback when the event occurs (of course, only when the event model 159callback when the event occurs (of course, only when the event model
148is in control). 160is in control).
149 161
150Note that B<callbacks must not permanently change global variables> 162Note that B<callbacks must not permanently change global variables>
151potentially 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<<
152callbacks must not C<die> >>. The former is good programming practise in 164callbacks must not C<die> >>. The former is good programming practice in
153Perl and the latter stems from the fact that exception handling differs 165Perl and the latter stems from the fact that exception handling differs
154widely between event loops. 166widely between event loops.
155 167
156To 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
157variable 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
158to it). 170to it).
159 171
160All 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.
161 173
162Many watchers either are used with "recursion" (repeating timers for 174Many watchers either are used with "recursion" (repeating timers for
163example), or need to refer to their watcher object in other ways. 175example), or need to refer to their watcher object in other ways.
164 176
165An any way to achieve that is this pattern: 177One way to achieve that is this pattern:
166 178
167 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 179 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168 # you can use $w here, for example to undef it 180 # you can use $w here, for example to undef it
169 undef $w; 181 undef $w;
170 }); 182 });
172Note that C<my $w; $w => combination. This is necessary because in Perl, 184Note that C<my $w; $w => combination. This is necessary because in Perl,
173my variables are only visible after the statement in which they are 185my variables are only visible after the statement in which they are
174declared. 186declared.
175 187
176=head2 I/O WATCHERS 188=head2 I/O WATCHERS
189
190 $w = AnyEvent->io (
191 fh => <filehandle_or_fileno>,
192 poll => <"r" or "w">,
193 cb => <callback>,
194 );
177 195
178You can create an I/O watcher by calling the C<< AnyEvent->io >> method 196You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179with the following mandatory key-value pairs as arguments: 197with the following mandatory key-value pairs as arguments:
180 198
181C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch 199C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
196 214
197The 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.
198You 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
199underlying file descriptor. 217underlying file descriptor.
200 218
201Some event loops issue spurious readyness notifications, so you should 219Some event loops issue spurious readiness notifications, so you should
202always use non-blocking calls when reading/writing from/to your file 220always use non-blocking calls when reading/writing from/to your file
203handles. 221handles.
204 222
205Example: 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
206watcher. 224watcher.
211 undef $w; 229 undef $w;
212 }); 230 });
213 231
214=head2 TIME WATCHERS 232=head2 TIME WATCHERS
215 233
234 $w = AnyEvent->timer (after => <seconds>, cb => <callback>);
235
236 $w = AnyEvent->timer (
237 after => <fractional_seconds>,
238 interval => <fractional_seconds>,
239 cb => <callback>,
240 );
241
216You can create a time watcher by calling the C<< AnyEvent->timer >> 242You can create a time watcher by calling the C<< AnyEvent->timer >>
217method with the following mandatory arguments: 243method with the following mandatory arguments:
218 244
219C<after> specifies after how many seconds (fractional values are 245C<after> specifies after how many seconds (fractional values are
220supported) the callback should be invoked. C<cb> is the callback to invoke 246supported) the callback should be invoked. C<cb> is the callback to invoke
222 248
223Although the callback might get passed parameters, their value and 249Although the callback might get passed parameters, their value and
224presence is undefined and you cannot rely on them. Portable AnyEvent 250presence is undefined and you cannot rely on them. Portable AnyEvent
225callbacks cannot use arguments passed to time watcher callbacks. 251callbacks cannot use arguments passed to time watcher callbacks.
226 252
227The callback will normally be invoked once only. If you specify another 253The callback will normally be invoked only once. If you specify another
228parameter, C<interval>, as a strictly positive number (> 0), then the 254parameter, C<interval>, as a strictly positive number (> 0), then the
229callback will be invoked regularly at that interval (in fractional 255callback will be invoked regularly at that interval (in fractional
230seconds) after the first invocation. If C<interval> is specified with a 256seconds) after the first invocation. If C<interval> is specified with a
231false value, then it is treated as if it were missing. 257false value, then it is treated as if it were not specified at all.
232 258
233The callback will be rescheduled before invoking the callback, but no 259The callback will be rescheduled before invoking the callback, but no
234attempt 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
235only approximate. 261only approximate.
236 262
237Example: fire an event after 7.7 seconds. 263Example: fire an event after 7.7 seconds.
238 264
239 my $w = AnyEvent->timer (after => 7.7, cb => sub { 265 my $w = AnyEvent->timer (after => 7.7, cb => sub {
257 283
258While 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
259use absolute time internally. This makes a difference when your clock 285use absolute time internally. This makes a difference when your clock
260"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
261the 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
262fire "after" a second might actually take six years to finally fire. 288fire "after a second" might actually take six years to finally fire.
263 289
264AnyEvent cannot compensate for this. The only event loop that is conscious 290AnyEvent cannot compensate for this. The only event loop that is conscious
265about 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
266on true relative time) and absolute (ev_periodic, based on wallclock time) 292on true relative time) and absolute (ev_periodic, based on wallclock time)
267timers. 293timers.
268 294
269AnyEvent always prefers relative timers, if available, matching the 295AnyEvent always prefers relative timers, if available, matching the
270AnyEvent API. 296AnyEvent API.
292I<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
293function to call when you want to know the current time.> 319function to call when you want to know the current time.>
294 320
295This function is also often faster then C<< AnyEvent->time >>, and 321This function is also often faster then C<< AnyEvent->time >>, and
296thus the preferred method if you want some timestamp (for example, 322thus the preferred method if you want some timestamp (for example,
297L<AnyEvent::Handle> uses this to update it's activity timeouts). 323L<AnyEvent::Handle> uses this to update its activity timeouts).
298 324
299The 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
300with your timing, you can skip it without bad conscience. 326with your timing; you can skip it without a bad conscience.
301 327
302For 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>
303and L<EV> and the following set-up: 329and L<EV> and the following set-up:
304 330
305The 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
306time=500 (assume no other callbacks delay processing). In your callback, 332time=500 (assume no other callbacks delay processing). In your callback,
307you 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
308second) 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
309after three seconds. 335after three seconds.
310 336
330difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 356difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331account. 357account.
332 358
333=item AnyEvent->now_update 359=item AnyEvent->now_update
334 360
335Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache 361Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
336the current time for each loop iteration (see the discussion of L<< 362time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
337AnyEvent->now >>, above). 363above).
338 364
339When a callback runs for a long time (or when the process sleeps), then 365When a callback runs for a long time (or when the process sleeps), then
340this "current" time will differ substantially from the real time, which 366this "current" time will differ substantially from the real time, which
341might affect timers and time-outs. 367might affect timers and time-outs.
342 368
343When this is the case, you can call this method, which will update the 369When this is the case, you can call this method, which will update the
344event loop's idea of "current time". 370event loop's idea of "current time".
345 371
372A typical example would be a script in a web server (e.g. C<mod_perl>) -
373when mod_perl executes the script, then the event loop will have the wrong
374idea about the "current time" (being potentially far in the past, when the
375script ran the last time). In that case you should arrange a call to C<<
376AnyEvent->now_update >> each time the web server process wakes up again
377(e.g. at the start of your script, or in a handler).
378
346Note that updating the time I<might> cause some events to be handled. 379Note that updating the time I<might> cause some events to be handled.
347 380
348=back 381=back
349 382
350=head2 SIGNAL WATCHERS 383=head2 SIGNAL WATCHERS
384
385 $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351 386
352You can watch for signals using a signal watcher, C<signal> is the signal 387You can watch for signals using a signal watcher, C<signal> is the signal
353I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl 388I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354callback to be invoked whenever a signal occurs. 389callback to be invoked whenever a signal occurs.
355 390
368 403
369This watcher might use C<%SIG> (depending on the event loop used), 404This watcher might use C<%SIG> (depending on the event loop used),
370so programs overwriting those signals directly will likely not work 405so programs overwriting those signals directly will likely not work
371correctly. 406correctly.
372 407
373Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not
374support attaching callbacks to signals, which is a pity, as you cannot do
375race-free signal handling in perl. AnyEvent will try to do it's best, but
376in some cases, signals will be delayed. The maximum time a signal might
377be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
378seconds). This variable can be changed only before the first signal
379watcher is created, and should be left alone otherwise. Higher values
380will cause fewer spurious wake-ups, which is better for power and CPU
381saving. All these problems can be avoided by installing the optional
382L<Async::Interrupt> module.
383
384Example: exit on SIGINT 408Example: exit on SIGINT
385 409
386 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 410 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
387 411
412=head3 Restart Behaviour
413
414While restart behaviour is up to the event loop implementation, most will
415not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
416pure perl implementation).
417
418=head3 Safe/Unsafe Signals
419
420Perl signals can be either "safe" (synchronous to opcode handling)
421or "unsafe" (asynchronous) - the former might delay signal delivery
422indefinitely, the latter might corrupt your memory.
423
424AnyEvent signal handlers are, in addition, synchronous to the event loop,
425i.e. they will not interrupt your running perl program but will only be
426called as part of the normal event handling (just like timer, I/O etc.
427callbacks, too).
428
429=head3 Signal Races, Delays and Workarounds
430
431Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
432attaching callbacks to signals in a generic way, which is a pity,
433as you cannot do race-free signal handling in perl, requiring
434C libraries for this. AnyEvent will try to do its best, which
435means in some cases, signals will be delayed. The maximum time
436a signal might be delayed is 10 seconds by default, but can
437be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
438C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
439section for details.
440
441All these problems can be avoided by installing the optional
442L<Async::Interrupt> module, which works with most event loops. It will not
443work with inherently broken event loops such as L<Event> or L<Event::Lib>
444(and not with L<POE> currently). For those, you just have to suffer the
445delays.
446
388=head2 CHILD PROCESS WATCHERS 447=head2 CHILD PROCESS WATCHERS
389 448
449 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
450
390You can also watch on a child process exit and catch its exit status. 451You can also watch for a child process exit and catch its exit status.
391 452
392The child process is specified by the C<pid> argument (if set to C<0>, it 453The child process is specified by the C<pid> argument (on some backends,
393watches for any child process exit). The watcher will triggered only when 454using C<0> watches for any child process exit, on others this will
394the child process has finished and an exit status is available, not on 455croak). The watcher will be triggered only when the child process has
395any trace events (stopped/continued). 456finished and an exit status is available, not on any trace events
457(stopped/continued).
396 458
397The callback will be called with the pid and exit status (as returned by 459The callback will be called with the pid and exit status (as returned by
398waitpid), so unlike other watcher types, you I<can> rely on child watcher 460waitpid), so unlike other watcher types, you I<can> rely on child watcher
399callback arguments. 461callback arguments.
400 462
418thing in an AnyEvent program, you I<have> to create at least one 480thing in an AnyEvent program, you I<have> to create at least one
419watcher before you C<fork> the child (alternatively, you can call 481watcher before you C<fork> the child (alternatively, you can call
420C<AnyEvent::detect>). 482C<AnyEvent::detect>).
421 483
422As most event loops do not support waiting for child events, they will be 484As most event loops do not support waiting for child events, they will be
423emulated by AnyEvent in most cases, in which the latency and race problems 485emulated by AnyEvent in most cases, in which case the latency and race
424mentioned in the description of signal watchers apply. 486problems mentioned in the description of signal watchers apply.
425 487
426Example: fork a process and wait for it 488Example: fork a process and wait for it
427 489
428 my $done = AnyEvent->condvar; 490 my $done = AnyEvent->condvar;
429 491
441 # do something else, then wait for process exit 503 # do something else, then wait for process exit
442 $done->recv; 504 $done->recv;
443 505
444=head2 IDLE WATCHERS 506=head2 IDLE WATCHERS
445 507
446Sometimes there is a need to do something, but it is not so important 508 $w = AnyEvent->idle (cb => <callback>);
447to do it instantly, but only when there is nothing better to do. This
448"nothing better to do" is usually defined to be "no other events need
449attention by the event loop".
450 509
451Idle watchers ideally get invoked when the event loop has nothing 510This will repeatedly invoke the callback after the process becomes idle,
452better to do, just before it would block the process to wait for new 511until either the watcher is destroyed or new events have been detected.
453events. Instead of blocking, the idle watcher is invoked.
454 512
455Most event loops unfortunately do not really support idle watchers (only 513Idle watchers are useful when there is a need to do something, but it
514is not so important (or wise) to do it instantly. The callback will be
515invoked only when there is "nothing better to do", which is usually
516defined as "all outstanding events have been handled and no new events
517have been detected". That means that idle watchers ideally get invoked
518when the event loop has just polled for new events but none have been
519detected. Instead of blocking to wait for more events, the idle watchers
520will be invoked.
521
522Unfortunately, most event loops do not really support idle watchers (only
456EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent 523EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
457will simply call the callback "from time to time". 524will simply call the callback "from time to time".
458 525
459Example: read lines from STDIN, but only process them when the 526Example: read lines from STDIN, but only process them when the
460program is otherwise idle: 527program is otherwise idle:
476 }); 543 });
477 }); 544 });
478 545
479=head2 CONDITION VARIABLES 546=head2 CONDITION VARIABLES
480 547
548 $cv = AnyEvent->condvar;
549
550 $cv->send (<list>);
551 my @res = $cv->recv;
552
481If you are familiar with some event loops you will know that all of them 553If you are familiar with some event loops you will know that all of them
482require you to run some blocking "loop", "run" or similar function that 554require you to run some blocking "loop", "run" or similar function that
483will actively watch for new events and call your callbacks. 555will actively watch for new events and call your callbacks.
484 556
485AnyEvent is slightly different: it expects somebody else to run the event 557AnyEvent is slightly different: it expects somebody else to run the event
486loop and will only block when necessary (usually when told by the user). 558loop and will only block when necessary (usually when told by the user).
487 559
488The instrument to do that is called a "condition variable", so called 560The tool to do that is called a "condition variable", so called because
489because they represent a condition that must become true. 561they represent a condition that must become true.
490 562
491Now is probably a good time to look at the examples further below. 563Now is probably a good time to look at the examples further below.
492 564
493Condition variables can be created by calling the C<< AnyEvent->condvar 565Condition variables can be created by calling the C<< AnyEvent->condvar
494>> method, usually without arguments. The only argument pair allowed is 566>> method, usually without arguments. The only argument pair allowed is
499After creation, the condition variable is "false" until it becomes "true" 571After creation, the condition variable is "false" until it becomes "true"
500by calling the C<send> method (or calling the condition variable as if it 572by calling the C<send> method (or calling the condition variable as if it
501were a callback, read about the caveats in the description for the C<< 573were a callback, read about the caveats in the description for the C<<
502->send >> method). 574->send >> method).
503 575
504Condition variables are similar to callbacks, except that you can 576Since condition variables are the most complex part of the AnyEvent API, here are
505optionally wait for them. They can also be called merge points - points 577some different mental models of what they are - pick the ones you can connect to:
506in time where multiple outstanding events have been processed. And yet 578
507another way to call them is transactions - each condition variable can be 579=over 4
508used to represent a transaction, which finishes at some point and delivers 580
509a result. 581=item * Condition variables are like callbacks - you can call them (and pass them instead
582of callbacks). Unlike callbacks however, you can also wait for them to be called.
583
584=item * Condition variables are signals - one side can emit or send them,
585the other side can wait for them, or install a handler that is called when
586the signal fires.
587
588=item * Condition variables are like "Merge Points" - points in your program
589where you merge multiple independent results/control flows into one.
590
591=item * Condition variables represent a transaction - functions that start
592some kind of transaction can return them, leaving the caller the choice
593between waiting in a blocking fashion, or setting a callback.
594
595=item * Condition variables represent future values, or promises to deliver
596some result, long before the result is available.
597
598=back
510 599
511Condition variables are very useful to signal that something has finished, 600Condition variables are very useful to signal that something has finished,
512for example, if you write a module that does asynchronous http requests, 601for example, if you write a module that does asynchronous http requests,
513then a condition variable would be the ideal candidate to signal the 602then a condition variable would be the ideal candidate to signal the
514availability of results. The user can either act when the callback is 603availability of results. The user can either act when the callback is
527 616
528Condition variables are represented by hash refs in perl, and the keys 617Condition variables are represented by hash refs in perl, and the keys
529used by AnyEvent itself are all named C<_ae_XXX> to make subclassing 618used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
530easy (it is often useful to build your own transaction class on top of 619easy (it is often useful to build your own transaction class on top of
531AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call 620AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
532it's C<new> method in your own C<new> method. 621its C<new> method in your own C<new> method.
533 622
534There are two "sides" to a condition variable - the "producer side" which 623There are two "sides" to a condition variable - the "producer side" which
535eventually calls C<< -> send >>, and the "consumer side", which waits 624eventually calls C<< -> send >>, and the "consumer side", which waits
536for the send to occur. 625for the send to occur.
537 626
538Example: wait for a timer. 627Example: wait for a timer.
539 628
540 # wait till the result is ready 629 # condition: "wait till the timer is fired"
541 my $result_ready = AnyEvent->condvar; 630 my $timer_fired = AnyEvent->condvar;
542 631
543 # do something such as adding a timer 632 # create the timer - we could wait for, say
544 # or socket watcher the calls $result_ready->send 633 # a handle becomign ready, or even an
545 # when the "result" is ready. 634 # AnyEvent::HTTP request to finish, but
546 # in this case, we simply use a timer: 635 # in this case, we simply use a timer:
547 my $w = AnyEvent->timer ( 636 my $w = AnyEvent->timer (
548 after => 1, 637 after => 1,
549 cb => sub { $result_ready->send }, 638 cb => sub { $timer_fired->send },
550 ); 639 );
551 640
552 # this "blocks" (while handling events) till the callback 641 # this "blocks" (while handling events) till the callback
553 # calls -<send 642 # calls ->send
554 $result_ready->recv; 643 $timer_fired->recv;
555 644
556Example: wait for a timer, but take advantage of the fact that condition 645Example: wait for a timer, but take advantage of the fact that condition
557variables are also callable directly. 646variables are also callable directly.
558 647
559 my $done = AnyEvent->condvar; 648 my $done = AnyEvent->condvar;
602they were a code reference). Calling them directly is the same as calling 691they were a code reference). Calling them directly is the same as calling
603C<send>. 692C<send>.
604 693
605=item $cv->croak ($error) 694=item $cv->croak ($error)
606 695
607Similar to send, but causes all call's to C<< ->recv >> to invoke 696Similar to send, but causes all calls to C<< ->recv >> to invoke
608C<Carp::croak> with the given error message/object/scalar. 697C<Carp::croak> with the given error message/object/scalar.
609 698
610This can be used to signal any errors to the condition variable 699This can be used to signal any errors to the condition variable
611user/consumer. Doing it this way instead of calling C<croak> directly 700user/consumer. Doing it this way instead of calling C<croak> directly
612delays the error detetcion, but has the overwhelmign advantage that it 701delays the error detection, but has the overwhelming advantage that it
613diagnoses the error at the place where the result is expected, and not 702diagnoses the error at the place where the result is expected, and not
614deep in some event clalback without connection to the actual code causing 703deep in some event callback with no connection to the actual code causing
615the problem. 704the problem.
616 705
617=item $cv->begin ([group callback]) 706=item $cv->begin ([group callback])
618 707
619=item $cv->end 708=item $cv->end
622one. For example, a function that pings many hosts in parallel might want 711one. For example, a function that pings many hosts in parallel might want
623to use a condition variable for the whole process. 712to use a condition variable for the whole process.
624 713
625Every call to C<< ->begin >> will increment a counter, and every call to 714Every call to C<< ->begin >> will increment a counter, and every call to
626C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 715C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
627>>, the (last) callback passed to C<begin> will be executed. That callback 716>>, the (last) callback passed to C<begin> will be executed, passing the
628is I<supposed> to call C<< ->send >>, but that is not required. If no 717condvar as first argument. That callback is I<supposed> to call C<< ->send
629callback was set, C<send> will be called without any arguments. 718>>, but that is not required. If no group callback was set, C<send> will
719be called without any arguments.
630 720
631You can think of C<< $cv->send >> giving you an OR condition (one call 721You can think of C<< $cv->send >> giving you an OR condition (one call
632sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND 722sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
633condition (all C<begin> calls must be C<end>'ed before the condvar sends). 723condition (all C<begin> calls must be C<end>'ed before the condvar sends).
634 724
656one call to C<begin>, so the condvar waits for all calls to C<end> before 746one call to C<begin>, so the condvar waits for all calls to C<end> before
657sending. 747sending.
658 748
659The ping example mentioned above is slightly more complicated, as the 749The ping example mentioned above is slightly more complicated, as the
660there are results to be passwd back, and the number of tasks that are 750there are results to be passwd back, and the number of tasks that are
661begung can potentially be zero: 751begun can potentially be zero:
662 752
663 my $cv = AnyEvent->condvar; 753 my $cv = AnyEvent->condvar;
664 754
665 my %result; 755 my %result;
666 $cv->begin (sub { $cv->send (\%result) }); 756 $cv->begin (sub { shift->send (\%result) });
667 757
668 for my $host (@list_of_hosts) { 758 for my $host (@list_of_hosts) {
669 $cv->begin; 759 $cv->begin;
670 ping_host_then_call_callback $host, sub { 760 ping_host_then_call_callback $host, sub {
671 $result{$host} = ...; 761 $result{$host} = ...;
687to be called once the counter reaches C<0>, and second, it ensures that 777to be called once the counter reaches C<0>, and second, it ensures that
688C<send> is called even when C<no> hosts are being pinged (the loop 778C<send> is called even when C<no> hosts are being pinged (the loop
689doesn't execute once). 779doesn't execute once).
690 780
691This is the general pattern when you "fan out" into multiple (but 781This is the general pattern when you "fan out" into multiple (but
692potentially none) subrequests: use an outer C<begin>/C<end> pair to set 782potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
693the callback and ensure C<end> is called at least once, and then, for each 783the callback and ensure C<end> is called at least once, and then, for each
694subrequest you start, call C<begin> and for each subrequest you finish, 784subrequest you start, call C<begin> and for each subrequest you finish,
695call C<end>. 785call C<end>.
696 786
697=back 787=back
704=over 4 794=over 4
705 795
706=item $cv->recv 796=item $cv->recv
707 797
708Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 798Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
709>> methods have been called on c<$cv>, while servicing other watchers 799>> methods have been called on C<$cv>, while servicing other watchers
710normally. 800normally.
711 801
712You can only wait once on a condition - additional calls are valid but 802You can only wait once on a condition - additional calls are valid but
713will return immediately. 803will return immediately.
714 804
731caller decide whether the call will block or not (for example, by coupling 821caller decide whether the call will block or not (for example, by coupling
732condition variables with some kind of request results and supporting 822condition variables with some kind of request results and supporting
733callbacks so the caller knows that getting the result will not block, 823callbacks so the caller knows that getting the result will not block,
734while still supporting blocking waits if the caller so desires). 824while still supporting blocking waits if the caller so desires).
735 825
736You can ensure that C<< -recv >> never blocks by setting a callback and 826You can ensure that C<< ->recv >> never blocks by setting a callback and
737only calling C<< ->recv >> from within that callback (or at a later 827only calling C<< ->recv >> from within that callback (or at a later
738time). This will work even when the event loop does not support blocking 828time). This will work even when the event loop does not support blocking
739waits otherwise. 829waits otherwise.
740 830
741=item $bool = $cv->ready 831=item $bool = $cv->ready
747 837
748This is a mutator function that returns the callback set and optionally 838This is a mutator function that returns the callback set and optionally
749replaces it before doing so. 839replaces it before doing so.
750 840
751The callback will be called when the condition becomes "true", i.e. when 841The callback will be called when the condition becomes "true", i.e. when
752C<send> or C<croak> are called, with the only argument being the condition 842C<send> or C<croak> are called, with the only argument being the
753variable itself. Calling C<recv> inside the callback or at any later time 843condition variable itself. If the condition is already true, the
754is guaranteed not to block. 844callback is called immediately when it is set. Calling C<recv> inside
845the callback or at any later time is guaranteed not to block.
755 846
756=back 847=back
757 848
758=head1 SUPPORTED EVENT LOOPS/BACKENDS 849=head1 SUPPORTED EVENT LOOPS/BACKENDS
759 850
762=over 4 853=over 4
763 854
764=item Backends that are autoprobed when no other event loop can be found. 855=item Backends that are autoprobed when no other event loop can be found.
765 856
766EV is the preferred backend when no other event loop seems to be in 857EV is the preferred backend when no other event loop seems to be in
767use. If EV is not installed, then AnyEvent will try Event, and, failing 858use. If EV is not installed, then AnyEvent will fall back to its own
768that, will fall back to its own pure-perl implementation, which is 859pure-perl implementation, which is available everywhere as it comes with
769available everywhere as it comes with AnyEvent itself. 860AnyEvent itself.
770 861
771 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 862 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
772 AnyEvent::Impl::Event based on Event, very stable, few glitches.
773 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 863 AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
774 864
775=item Backends that are transparently being picked up when they are used. 865=item Backends that are transparently being picked up when they are used.
776 866
777These will be used when they are currently loaded when the first watcher 867These will be used if they are already loaded when the first watcher
778is created, in which case it is assumed that the application is using 868is created, in which case it is assumed that the application is using
779them. This means that AnyEvent will automatically pick the right backend 869them. This means that AnyEvent will automatically pick the right backend
780when the main program loads an event module before anything starts to 870when the main program loads an event module before anything starts to
781create watchers. Nothing special needs to be done by the main program. 871create watchers. Nothing special needs to be done by the main program.
782 872
873 AnyEvent::Impl::Event based on Event, very stable, few glitches.
783 AnyEvent::Impl::Glib based on Glib, slow but very stable. 874 AnyEvent::Impl::Glib based on Glib, slow but very stable.
784 AnyEvent::Impl::Tk based on Tk, very broken. 875 AnyEvent::Impl::Tk based on Tk, very broken.
785 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 876 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
786 AnyEvent::Impl::POE based on POE, very slow, some limitations. 877 AnyEvent::Impl::POE based on POE, very slow, some limitations.
878 AnyEvent::Impl::Irssi used when running within irssi.
879 AnyEvent::Impl::IOAsync based on IO::Async.
880 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
881 AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
787 882
788=item Backends with special needs. 883=item Backends with special needs.
789 884
790Qt requires the Qt::Application to be instantiated first, but will 885Qt requires the Qt::Application to be instantiated first, but will
791otherwise be picked up automatically. As long as the main program 886otherwise be picked up automatically. As long as the main program
792instantiates the application before any AnyEvent watchers are created, 887instantiates the application before any AnyEvent watchers are created,
793everything should just work. 888everything should just work.
794 889
795 AnyEvent::Impl::Qt based on Qt. 890 AnyEvent::Impl::Qt based on Qt.
796 891
797Support for IO::Async can only be partial, as it is too broken and
798architecturally limited to even support the AnyEvent API. It also
799is the only event loop that needs the loop to be set explicitly, so
800it can only be used by a main program knowing about AnyEvent. See
801L<AnyEvent::Impl::Async> for the gory details.
802
803 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
804
805=item Event loops that are indirectly supported via other backends. 892=item Event loops that are indirectly supported via other backends.
806 893
807Some event loops can be supported via other modules: 894Some event loops can be supported via other modules:
808 895
809There is no direct support for WxWidgets (L<Wx>) or L<Prima>. 896There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
834Contains C<undef> until the first watcher is being created, before the 921Contains C<undef> until the first watcher is being created, before the
835backend has been autodetected. 922backend has been autodetected.
836 923
837Afterwards it contains the event model that is being used, which is the 924Afterwards it contains the event model that is being used, which is the
838name of the Perl class implementing the model. This class is usually one 925name of the Perl class implementing the model. This class is usually one
839of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the 926of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
840case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it 927case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
841will be C<urxvt::anyevent>). 928will be C<urxvt::anyevent>).
842 929
843=item AnyEvent::detect 930=item AnyEvent::detect
844 931
845Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 932Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
846if necessary. You should only call this function right before you would 933if necessary. You should only call this function right before you would
847have created an AnyEvent watcher anyway, that is, as late as possible at 934have created an AnyEvent watcher anyway, that is, as late as possible at
848runtime, and not e.g. while initialising of your module. 935runtime, and not e.g. during initialisation of your module.
936
937The effect of calling this function is as if a watcher had been created
938(specifically, actions that happen "when the first watcher is created"
939happen when calling detetc as well).
849 940
850If you need to do some initialisation before AnyEvent watchers are 941If you need to do some initialisation before AnyEvent watchers are
851created, use C<post_detect>. 942created, use C<post_detect>.
852 943
853=item $guard = AnyEvent::post_detect { BLOCK } 944=item $guard = AnyEvent::post_detect { BLOCK }
854 945
855Arranges for the code block to be executed as soon as the event model is 946Arranges for the code block to be executed as soon as the event model is
856autodetected (or immediately if this has already happened). 947autodetected (or immediately if that has already happened).
857 948
858The block will be executed I<after> the actual backend has been detected 949The block will be executed I<after> the actual backend has been detected
859(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been 950(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
860created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do 951created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
861other initialisations - see the sources of L<AnyEvent::Strict> or 952other initialisations - see the sources of L<AnyEvent::Strict> or
865event module detection too early, for example, L<AnyEvent::AIO> creates 956event module detection too early, for example, L<AnyEvent::AIO> creates
866and installs the global L<IO::AIO> watcher in a C<post_detect> block to 957and installs the global L<IO::AIO> watcher in a C<post_detect> block to
867avoid autodetecting the event module at load time. 958avoid autodetecting the event module at load time.
868 959
869If called in scalar or list context, then it creates and returns an object 960If called in scalar or list context, then it creates and returns an object
870that automatically removes the callback again when it is destroyed. See 961that automatically removes the callback again when it is destroyed (or
962C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
871L<Coro::BDB> for a case where this is useful. 963a case where this is useful.
964
965Example: Create a watcher for the IO::AIO module and store it in
966C<$WATCHER>, but do so only do so after the event loop is initialised.
967
968 our WATCHER;
969
970 my $guard = AnyEvent::post_detect {
971 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
972 };
973
974 # the ||= is important in case post_detect immediately runs the block,
975 # as to not clobber the newly-created watcher. assigning both watcher and
976 # post_detect guard to the same variable has the advantage of users being
977 # able to just C<undef $WATCHER> if the watcher causes them grief.
978
979 $WATCHER ||= $guard;
872 980
873=item @AnyEvent::post_detect 981=item @AnyEvent::post_detect
874 982
875If there are any code references in this array (you can C<push> to it 983If there are any code references in this array (you can C<push> to it
876before or after loading AnyEvent), then they will called directly after 984before or after loading AnyEvent), then they will be called directly
877the event loop has been chosen. 985after the event loop has been chosen.
878 986
879You should check C<$AnyEvent::MODEL> before adding to this array, though: 987You should check C<$AnyEvent::MODEL> before adding to this array, though:
880if it is defined then the event loop has already been detected, and the 988if it is defined then the event loop has already been detected, and the
881array will be ignored. 989array will be ignored.
882 990
883Best use C<AnyEvent::post_detect { BLOCK }> when your application allows 991Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
884it,as it takes care of these details. 992it, as it takes care of these details.
885 993
886This variable is mainly useful for modules that can do something useful 994This variable is mainly useful for modules that can do something useful
887when AnyEvent is used and thus want to know when it is initialised, but do 995when AnyEvent is used and thus want to know when it is initialised, but do
888not need to even load it by default. This array provides the means to hook 996not need to even load it by default. This array provides the means to hook
889into AnyEvent passively, without loading it. 997into AnyEvent passively, without loading it.
890 998
999Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
1000together, you could put this into Coro (this is the actual code used by
1001Coro to accomplish this):
1002
1003 if (defined $AnyEvent::MODEL) {
1004 # AnyEvent already initialised, so load Coro::AnyEvent
1005 require Coro::AnyEvent;
1006 } else {
1007 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
1008 # as soon as it is
1009 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
1010 }
1011
1012=item AnyEvent::postpone { BLOCK }
1013
1014Arranges for the block to be executed as soon as possible, but not before
1015the call itself returns. In practise, the block will be executed just
1016before the event loop polls for new events, or shortly afterwards.
1017
1018This function never returns anything (to make the C<return postpone { ...
1019}> idiom more useful.
1020
1021To understand the usefulness of this function, consider a function that
1022asynchronously does something for you and returns some transaction
1023object or guard to let you cancel the operation. For example,
1024C<AnyEvent::Socket::tcp_connect>:
1025
1026 # start a conenction attempt unless one is active
1027 $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
1028 delete $self->{connect_guard};
1029 ...
1030 };
1031
1032Imagine that this function could instantly call the callback, for
1033example, because it detects an obvious error such as a negative port
1034number. Invoking the callback before the function returns causes problems
1035however: the callback will be called and will try to delete the guard
1036object. But since the function hasn't returned yet, there is nothing to
1037delete. When the function eventually returns it will assign the guard
1038object to C<< $self->{connect_guard} >>, where it will likely never be
1039deleted, so the program thinks it is still trying to connect.
1040
1041This is where C<AnyEvent::postpone> should be used. Instead of calling the
1042callback directly on error:
1043
1044 $cb->(undef), return # signal error to callback, BAD!
1045 if $some_error_condition;
1046
1047It should use C<postpone>:
1048
1049 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1050 if $some_error_condition;
1051
1052=item AnyEvent::log $level, $msg[, @args]
1053
1054Log the given C<$msg> at the given C<$level>.
1055
1056If L<AnyEvent::Log> is not loaded then this function makes a simple test
1057to see whether the message will be logged. If the test succeeds it will
1058load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
1059the L<AnyEvent::Log> documentation for details.
1060
1061If the test fails it will simply return. Right now this happens when a
1062numerical loglevel is used and it is larger than the level specified via
1063C<$ENV{PERL_ANYEVENT_VERBOSE}>.
1064
1065If you want to sprinkle loads of logging calls around your code, consider
1066creating a logger callback with the C<AnyEvent::Log::logger> function,
1067which can reduce typing, codesize and can reduce the logging overhead
1068enourmously.
1069
891=back 1070=back
892 1071
893=head1 WHAT TO DO IN A MODULE 1072=head1 WHAT TO DO IN A MODULE
894 1073
895As a module author, you should C<use AnyEvent> and call AnyEvent methods 1074As a module author, you should C<use AnyEvent> and call AnyEvent methods
905because it will stall the whole program, and the whole point of using 1084because it will stall the whole program, and the whole point of using
906events is to stay interactive. 1085events is to stay interactive.
907 1086
908It is fine, however, to call C<< ->recv >> when the user of your module 1087It is fine, however, to call C<< ->recv >> when the user of your module
909requests it (i.e. if you create a http request object ad have a method 1088requests it (i.e. if you create a http request object ad have a method
910called C<results> that returns the results, it should call C<< ->recv >> 1089called C<results> that returns the results, it may call C<< ->recv >>
911freely, as the user of your module knows what she is doing. always). 1090freely, as the user of your module knows what she is doing. Always).
912 1091
913=head1 WHAT TO DO IN THE MAIN PROGRAM 1092=head1 WHAT TO DO IN THE MAIN PROGRAM
914 1093
915There will always be a single main program - the only place that should 1094There will always be a single main program - the only place that should
916dictate which event model to use. 1095dictate which event model to use.
917 1096
918If it doesn't care, it can just "use AnyEvent" and use it itself, or not 1097If the program is not event-based, it need not do anything special, even
919do anything special (it does not need to be event-based) and let AnyEvent 1098when it depends on a module that uses an AnyEvent. If the program itself
920decide which implementation to chose if some module relies on it. 1099uses AnyEvent, but does not care which event loop is used, all it needs
1100to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
1101available loop implementation.
921 1102
922If the main program relies on a specific event model - for example, in 1103If the main program relies on a specific event model - for example, in
923Gtk2 programs you have to rely on the Glib module - you should load the 1104Gtk2 programs you have to rely on the Glib module - you should load the
924event module before loading AnyEvent or any module that uses it: generally 1105event module before loading AnyEvent or any module that uses it: generally
925speaking, you should load it as early as possible. The reason is that 1106speaking, you should load it as early as possible. The reason is that
926modules might create watchers when they are loaded, and AnyEvent will 1107modules might create watchers when they are loaded, and AnyEvent will
927decide on the event model to use as soon as it creates watchers, and it 1108decide on the event model to use as soon as it creates watchers, and it
928might chose the wrong one unless you load the correct one yourself. 1109might choose the wrong one unless you load the correct one yourself.
929 1110
930You can chose to use a pure-perl implementation by loading the 1111You can chose to use a pure-perl implementation by loading the
931C<AnyEvent::Impl::Perl> module, which gives you similar behaviour 1112C<AnyEvent::Loop> module, which gives you similar behaviour
932everywhere, but letting AnyEvent chose the model is generally better. 1113everywhere, but letting AnyEvent chose the model is generally better.
933 1114
934=head2 MAINLOOP EMULATION 1115=head2 MAINLOOP EMULATION
935 1116
936Sometimes (often for short test scripts, or even standalone programs who 1117Sometimes (often for short test scripts, or even standalone programs who
949 1130
950 1131
951=head1 OTHER MODULES 1132=head1 OTHER MODULES
952 1133
953The following is a non-exhaustive list of additional modules that use 1134The following is a non-exhaustive list of additional modules that use
954AnyEvent as a client and can therefore be mixed easily with other AnyEvent 1135AnyEvent as a client and can therefore be mixed easily with other
955modules and other event loops in the same program. Some of the modules 1136AnyEvent modules and other event loops in the same program. Some of the
956come with AnyEvent, most are available via CPAN. 1137modules come as part of AnyEvent, the others are available via CPAN (see
1138L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
1139a longer non-exhaustive list), and the list is heavily biased towards
1140modules of the AnyEvent author himself :)
957 1141
958=over 4 1142=over 4
959 1143
960=item L<AnyEvent::Util> 1144=item L<AnyEvent::Util>
961 1145
962Contains various utility functions that replace often-used but blocking 1146Contains various utility functions that replace often-used blocking
963functions such as C<inet_aton> by event-/callback-based versions. 1147functions such as C<inet_aton> with event/callback-based versions.
964 1148
965=item L<AnyEvent::Socket> 1149=item L<AnyEvent::Socket>
966 1150
967Provides various utility functions for (internet protocol) sockets, 1151Provides various utility functions for (internet protocol) sockets,
968addresses and name resolution. Also functions to create non-blocking tcp 1152addresses and name resolution. Also functions to create non-blocking tcp
970 1154
971=item L<AnyEvent::Handle> 1155=item L<AnyEvent::Handle>
972 1156
973Provide read and write buffers, manages watchers for reads and writes, 1157Provide read and write buffers, manages watchers for reads and writes,
974supports raw and formatted I/O, I/O queued and fully transparent and 1158supports raw and formatted I/O, I/O queued and fully transparent and
975non-blocking SSL/TLS (via L<AnyEvent::TLS>. 1159non-blocking SSL/TLS (via L<AnyEvent::TLS>).
976 1160
977=item L<AnyEvent::DNS> 1161=item L<AnyEvent::DNS>
978 1162
979Provides rich asynchronous DNS resolver capabilities. 1163Provides rich asynchronous DNS resolver capabilities.
980 1164
1165=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
1166
1167Implement event-based interfaces to the protocols of the same name (for
1168the curious, IGS is the International Go Server and FCP is the Freenet
1169Client Protocol).
1170
981=item L<AnyEvent::HTTP> 1171=item L<AnyEvent::AIO>
982 1172
983A simple-to-use HTTP library that is capable of making a lot of concurrent 1173Truly asynchronous (as opposed to non-blocking) I/O, should be in the
984HTTP requests. 1174toolbox of every event programmer. AnyEvent::AIO transparently fuses
1175L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
1176file I/O, and much more.
1177
1178=item L<AnyEvent::Filesys::Notify>
1179
1180AnyEvent is good for non-blocking stuff, but it can't detect file or
1181path changes (e.g. "watch this directory for new files", "watch this
1182file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
1183do just that in a portbale fashion, supporting inotify on GNU/Linux and
1184some weird, without doubt broken, stuff on OS X to monitor files. It can
1185fall back to blocking scans at regular intervals transparently on other
1186platforms, so it's about as portable as it gets.
1187
1188(I haven't used it myself, but I haven't heard anybody complaining about
1189it yet).
1190
1191=item L<AnyEvent::DBI>
1192
1193Executes L<DBI> requests asynchronously in a proxy process for you,
1194notifying you in an event-based way when the operation is finished.
985 1195
986=item L<AnyEvent::HTTPD> 1196=item L<AnyEvent::HTTPD>
987 1197
988Provides a simple web application server framework. 1198A simple embedded webserver.
989 1199
990=item L<AnyEvent::FastPing> 1200=item L<AnyEvent::FastPing>
991 1201
992The fastest ping in the west. 1202The fastest ping in the west.
993 1203
994=item L<AnyEvent::DBI>
995
996Executes L<DBI> requests asynchronously in a proxy process.
997
998=item L<AnyEvent::AIO>
999
1000Truly asynchronous I/O, should be in the toolbox of every event
1001programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1002together.
1003
1004=item L<AnyEvent::BDB>
1005
1006Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1007L<BDB> and AnyEvent together.
1008
1009=item L<AnyEvent::GPSD>
1010
1011A non-blocking interface to gpsd, a daemon delivering GPS information.
1012
1013=item L<AnyEvent::IRC>
1014
1015AnyEvent based IRC client module family (replacing the older Net::IRC3).
1016
1017=item L<AnyEvent::XMPP>
1018
1019AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1020Net::XMPP2>.
1021
1022=item L<AnyEvent::IGS>
1023
1024A non-blocking interface to the Internet Go Server protocol (used by
1025L<App::IGS>).
1026
1027=item L<Net::FCP>
1028
1029AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1030of AnyEvent.
1031
1032=item L<Event::ExecFlow>
1033
1034High level API for event-based execution flow control.
1035
1036=item L<Coro> 1204=item L<Coro>
1037 1205
1038Has special support for AnyEvent via L<Coro::AnyEvent>. 1206Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
1207to simply invert the flow control - don't call us, we will call you:
1208
1209 async {
1210 Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
1211 print "5 seconds later!\n";
1212
1213 Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
1214 my $line = <STDIN>; # works for ttys
1215
1216 AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
1217 my ($body, $hdr) = Coro::rouse_wait;
1218 };
1039 1219
1040=back 1220=back
1041 1221
1042=cut 1222=cut
1043 1223
1044package AnyEvent; 1224package AnyEvent;
1045 1225
1046# basically a tuned-down version of common::sense 1226# basically a tuned-down version of common::sense
1047sub common_sense { 1227sub common_sense {
1048 # no warnings 1228 # from common:.sense 3.5
1049 ${^WARNING_BITS} ^= ${^WARNING_BITS}; 1229 local $^W;
1050 # use strict vars subs 1230 ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1231 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1051 $^H |= 0x00000600; 1232 $^H |= 0x00000600;
1052} 1233}
1053 1234
1054BEGIN { AnyEvent::common_sense } 1235BEGIN { AnyEvent::common_sense }
1055 1236
1056use Carp (); 1237use Carp ();
1057 1238
1058our $VERSION = 4.83; 1239our $VERSION = '6.14';
1059our $MODEL; 1240our $MODEL;
1060
1061our $AUTOLOAD;
1062our @ISA; 1241our @ISA;
1063
1064our @REGISTRY; 1242our @REGISTRY;
1065
1066our $WIN32;
1067
1068our $VERBOSE; 1243our $VERBOSE;
1244our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1245our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1069 1246
1070BEGIN { 1247BEGIN {
1071 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1248 require "AnyEvent/constants.pl";
1249
1072 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1250 eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1073 1251
1074 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1252 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1075 if ${^TAINT}; 1253 if ${^TAINT};
1076 1254
1077 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1255 $ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
1256 for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1078 1257
1079} 1258 @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
1259 if ${^TAINT};
1080 1260
1081our $MAX_SIGNAL_LATENCY = 10; 1261 # $ENV{PERL_ANYEVENT_xxx} now valid
1082 1262
1083our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1263 $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1084 1264
1085{
1086 my $idx; 1265 my $idx;
1087 $PROTOCOL{$_} = ++$idx 1266 $PROTOCOL{$_} = ++$idx
1088 for reverse split /\s*,\s*/, 1267 for reverse split /\s*,\s*/,
1089 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1268 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1090} 1269}
1091 1270
1271our @post_detect;
1272
1273sub post_detect(&) {
1274 my ($cb) = @_;
1275
1276 push @post_detect, $cb;
1277
1278 defined wantarray
1279 ? bless \$cb, "AnyEvent::Util::postdetect"
1280 : ()
1281}
1282
1283sub AnyEvent::Util::postdetect::DESTROY {
1284 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1285}
1286
1287our $POSTPONE_W;
1288our @POSTPONE;
1289
1290sub _postpone_exec {
1291 undef $POSTPONE_W;
1292
1293 &{ shift @POSTPONE }
1294 while @POSTPONE;
1295}
1296
1297sub postpone(&) {
1298 push @POSTPONE, shift;
1299
1300 $POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
1301
1302 ()
1303}
1304
1305sub log($$;@) {
1306 # only load the big bloated module when we actually are about to log something
1307 if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
1308 local ($!, $@);
1309 require AnyEvent::Log; # among other things, sets $VERBOSE to 9
1310 # AnyEvent::Log overwrites this function
1311 goto &log;
1312 }
1313
1314 0 # not logged
1315}
1316
1317sub _logger($;$) {
1318 my ($level, $renabled) = @_;
1319
1320 $$renabled = $level <= $VERBOSE;
1321
1322 my $logger = [(caller)[0], $level, $renabled];
1323
1324 $AnyEvent::Log::LOGGER{$logger+0} = $logger;
1325
1326# return unless defined wantarray;
1327#
1328# require AnyEvent::Util;
1329# my $guard = AnyEvent::Util::guard (sub {
1330# # "clean up"
1331# delete $LOGGER{$logger+0};
1332# });
1333#
1334# sub {
1335# return 0 unless $$renabled;
1336#
1337# $guard if 0; # keep guard alive, but don't cause runtime overhead
1338# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
1339# package AnyEvent::Log;
1340# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
1341# }
1342}
1343
1344if (length $ENV{PERL_ANYEVENT_LOG}) {
1345 require AnyEvent::Log; # AnyEvent::Log does the thing for us
1346}
1347
1092my @models = ( 1348our @models = (
1093 [EV:: => AnyEvent::Impl::EV::], 1349 [EV:: => AnyEvent::Impl::EV::],
1094 [Event:: => AnyEvent::Impl::Event::],
1095 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1350 [AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1096 # everything below here will not be autoprobed 1351 # everything below here will not (normally) be autoprobed
1097 # as the pureperl backend should work everywhere 1352 # as the pure perl backend should work everywhere
1098 # and is usually faster 1353 # and is usually faster
1354 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
1355 [Event:: => AnyEvent::Impl::Event::], # slow, stable
1099 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1356 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1357 # everything below here should not be autoloaded
1100 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1358 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1101 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1359 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1102 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1360 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1103 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1361 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1104 [Wx:: => AnyEvent::Impl::POE::], 1362 [Wx:: => AnyEvent::Impl::POE::],
1105 [Prima:: => AnyEvent::Impl::POE::], 1363 [Prima:: => AnyEvent::Impl::POE::],
1106 # IO::Async is just too broken - we would need workarounds for its 1364 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1107 # byzantine signal and broken child handling, among others. 1365 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1108 # IO::Async is rather hard to detect, as it doesn't have any 1366 [FLTK:: => AnyEvent::Impl::FLTK::],
1109 # obvious default class.
1110# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1111# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1112# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1113); 1367);
1114 1368
1115our %method = map +($_ => 1), 1369our @isa_hook;
1370
1371sub _isa_set {
1372 my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
1373
1374 @{"$pkg[$_-1]::ISA"} = $pkg[$_]
1375 for 1 .. $#pkg;
1376
1377 grep $_ && $_->[1], @isa_hook
1378 and AE::_reset ();
1379}
1380
1381# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
1382sub _isa_hook($$;$) {
1383 my ($i, $pkg, $reset_ae) = @_;
1384
1385 $isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
1386
1387 _isa_set;
1388}
1389
1390# all autoloaded methods reserve the complete glob, not just the method slot.
1391# due to bugs in perls method cache implementation.
1116 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1392our @methods = qw(io timer time now now_update signal child idle condvar);
1117 1393
1118our @post_detect;
1119
1120sub post_detect(&) { 1394sub detect() {
1121 my ($cb) = @_; 1395 return $MODEL if $MODEL; # some programs keep references to detect
1122 1396
1123 if ($MODEL) { 1397 # IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1124 $cb->(); 1398 # the author knows about the problems and what it does to AnyEvent as a whole
1399 # (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
1400 # anyway.
1401 AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
1402 . "design, abuses internals and breaks AnyEvent - will not continue."
1403 if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1125 1404
1126 1 1405 local $!; # for good measure
1406 local $SIG{__DIE__}; # we use eval
1407
1408 # free some memory
1409 *detect = sub () { $MODEL };
1410 # undef &func doesn't correctly update the method cache. grmbl.
1411 # so we delete the whole glob. grmbl.
1412 # otoh, perl doesn't let me undef an active usb, but it lets me free
1413 # a glob with an active sub. hrm. i hope it works, but perl is
1414 # usually buggy in this department. sigh.
1415 delete @{"AnyEvent::"}{@methods};
1416 undef @methods;
1417
1418 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
1419 my $model = $1;
1420 $model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
1421 if (eval "require $model") {
1422 AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
1423 $MODEL = $model;
1127 } else { 1424 } else {
1128 push @post_detect, $cb; 1425 AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1129 1426 }
1130 defined wantarray
1131 ? bless \$cb, "AnyEvent::Util::postdetect"
1132 : ()
1133 } 1427 }
1134}
1135 1428
1136sub AnyEvent::Util::postdetect::DESTROY { 1429 # check for already loaded models
1137 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1138}
1139
1140sub detect() {
1141 unless ($MODEL) { 1430 unless ($MODEL) {
1142 local $SIG{__DIE__}; 1431 for (@REGISTRY, @models) {
1143 1432 my ($package, $model) = @$_;
1144 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1433 if (${"$package\::VERSION"} > 0) {
1145 my $model = "AnyEvent::Impl::$1";
1146 if (eval "require $model") { 1434 if (eval "require $model") {
1435 AnyEvent::log 7 => "Autodetected model '$model', using it.";
1147 $MODEL = $model; 1436 $MODEL = $model;
1148 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; 1437 last;
1149 } else { 1438 } else {
1150 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; 1439 AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
1440 }
1151 } 1441 }
1152 } 1442 }
1153 1443
1154 # check for already loaded models
1155 unless ($MODEL) { 1444 unless ($MODEL) {
1445 # try to autoload a model
1156 for (@REGISTRY, @models) { 1446 for (@REGISTRY, @models) {
1157 my ($package, $model) = @$_; 1447 my ($package, $model) = @$_;
1448 if (
1449 eval "require $package"
1158 if (${"$package\::VERSION"} > 0) { 1450 and ${"$package\::VERSION"} > 0
1159 if (eval "require $model") { 1451 and eval "require $model"
1452 ) {
1453 AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1160 $MODEL = $model; 1454 $MODEL = $model;
1161 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1162 last; 1455 last;
1163 }
1164 } 1456 }
1165 } 1457 }
1166 1458
1167 unless ($MODEL) {
1168 # try to load a model
1169
1170 for (@REGISTRY, @models) {
1171 my ($package, $model) = @$_;
1172 if (eval "require $package"
1173 and ${"$package\::VERSION"} > 0
1174 and eval "require $model") {
1175 $MODEL = $model;
1176 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1177 last;
1178 }
1179 }
1180
1181 $MODEL 1459 $MODEL
1182 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; 1460 or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1183 }
1184 } 1461 }
1185
1186 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1187
1188 unshift @ISA, $MODEL;
1189
1190 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1191
1192 (shift @post_detect)->() while @post_detect;
1193 } 1462 }
1194 1463
1464 # free memory only needed for probing
1465 undef @models;
1466 undef @REGISTRY;
1467
1468 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1469
1470 # now nuke some methods that are overridden by the backend.
1471 # SUPER usage is not allowed in these.
1472 for (qw(time signal child idle)) {
1473 undef &{"AnyEvent::Base::$_"}
1474 if defined &{"$MODEL\::$_"};
1475 }
1476
1477 _isa_set;
1478
1479 # we're officially open!
1480
1481 if ($ENV{PERL_ANYEVENT_STRICT}) {
1482 require AnyEvent::Strict;
1483 }
1484
1485 if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
1486 require AnyEvent::Debug;
1487 AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
1488 }
1489
1490 if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
1491 require AnyEvent::Socket;
1492 require AnyEvent::Debug;
1493
1494 my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
1495 $shell =~ s/\$\$/$$/g;
1496
1497 my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
1498 $AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
1499 }
1500
1501 # now the anyevent environment is set up as the user told us to, so
1502 # call the actual user code - post detects
1503
1504 (shift @post_detect)->() while @post_detect;
1505 undef @post_detect;
1506
1507 *post_detect = sub(&) {
1508 shift->();
1509
1510 undef
1511 };
1512
1195 $MODEL 1513 $MODEL
1196} 1514}
1197 1515
1198sub AUTOLOAD { 1516for my $name (@methods) {
1199 (my $func = $AUTOLOAD) =~ s/.*://; 1517 *$name = sub {
1200 1518 detect;
1201 $method{$func} 1519 # we use goto because
1202 or Carp::croak "$func: not a valid method for AnyEvent objects"; 1520 # a) it makes the thunk more transparent
1203 1521 # b) it allows us to delete the thunk later
1204 detect unless $MODEL; 1522 goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1205 1523 };
1206 my $class = shift;
1207 $class->$func (@_);
1208} 1524}
1209 1525
1210# utility function to dup a filehandle. this is used by many backends 1526# utility function to dup a filehandle. this is used by many backends
1211# to support binding more than one watcher per filehandle (they usually 1527# to support binding more than one watcher per filehandle (they usually
1212# allow only one watcher per fd, so we dup it to get a different one). 1528# allow only one watcher per fd, so we dup it to get a different one).
1222 # we assume CLOEXEC is already set by perl in all important cases 1538 # we assume CLOEXEC is already set by perl in all important cases
1223 1539
1224 ($fh2, $rw) 1540 ($fh2, $rw)
1225} 1541}
1226 1542
1543=head1 SIMPLIFIED AE API
1544
1545Starting with version 5.0, AnyEvent officially supports a second, much
1546simpler, API that is designed to reduce the calling, typing and memory
1547overhead by using function call syntax and a fixed number of parameters.
1548
1549See the L<AE> manpage for details.
1550
1551=cut
1552
1553package AE;
1554
1555our $VERSION = $AnyEvent::VERSION;
1556
1557sub _reset() {
1558 eval q{
1559 # fall back to the main API by default - backends and AnyEvent::Base
1560 # implementations can overwrite these.
1561
1562 sub io($$$) {
1563 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1564 }
1565
1566 sub timer($$$) {
1567 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1568 }
1569
1570 sub signal($$) {
1571 AnyEvent->signal (signal => $_[0], cb => $_[1])
1572 }
1573
1574 sub child($$) {
1575 AnyEvent->child (pid => $_[0], cb => $_[1])
1576 }
1577
1578 sub idle($) {
1579 AnyEvent->idle (cb => $_[0]);
1580 }
1581
1582 sub cv(;&) {
1583 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1584 }
1585
1586 sub now() {
1587 AnyEvent->now
1588 }
1589
1590 sub now_update() {
1591 AnyEvent->now_update
1592 }
1593
1594 sub time() {
1595 AnyEvent->time
1596 }
1597
1598 *postpone = \&AnyEvent::postpone;
1599 *log = \&AnyEvent::log;
1600 };
1601 die if $@;
1602}
1603
1604BEGIN { _reset }
1605
1227package AnyEvent::Base; 1606package AnyEvent::Base;
1228 1607
1229# default implementations for many methods 1608# default implementations for many methods
1230 1609
1231sub _time { 1610sub time {
1611 eval q{ # poor man's autoloading {}
1232 # probe for availability of Time::HiRes 1612 # probe for availability of Time::HiRes
1233 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1613 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1234 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1614 *time = sub { Time::HiRes::time () };
1235 *_time = \&Time::HiRes::time; 1615 *AE::time = \& Time::HiRes::time ;
1616 *now = \&time;
1617 AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1236 # if (eval "use POSIX (); (POSIX::times())... 1618 # if (eval "use POSIX (); (POSIX::times())...
1237 } else { 1619 } else {
1238 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; 1620 *time = sub { CORE::time };
1239 *_time = sub { time }; # epic fail 1621 *AE::time = sub (){ CORE::time };
1622 *now = \&time;
1623 AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
1624 }
1240 } 1625 };
1626 die if $@;
1241 1627
1242 &_time 1628 &time
1243} 1629}
1244 1630
1245sub time { _time } 1631*now = \&time;
1246sub now { _time }
1247sub now_update { } 1632sub now_update { }
1248 1633
1634sub _poll {
1635 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
1636}
1637
1249# default implementation for ->condvar 1638# default implementation for ->condvar
1639# in fact, the default should not be overwritten
1250 1640
1251sub condvar { 1641sub condvar {
1642 eval q{ # poor man's autoloading {}
1643 *condvar = sub {
1252 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1644 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1645 };
1646
1647 *AE::cv = sub (;&) {
1648 bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
1649 };
1650 };
1651 die if $@;
1652
1653 &condvar
1253} 1654}
1254 1655
1255# default implementation for ->signal 1656# default implementation for ->signal
1256 1657
1257our $HAVE_ASYNC_INTERRUPT; 1658our $HAVE_ASYNC_INTERRUPT;
1659
1660sub _have_async_interrupt() {
1661 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1662 && eval "use Async::Interrupt 1.02 (); 1")
1663 unless defined $HAVE_ASYNC_INTERRUPT;
1664
1665 $HAVE_ASYNC_INTERRUPT
1666}
1667
1258our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1668our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1259our (%SIG_ASY, %SIG_ASY_W); 1669our (%SIG_ASY, %SIG_ASY_W);
1260our ($SIG_COUNT, $SIG_TW); 1670our ($SIG_COUNT, $SIG_TW);
1261 1671
1262sub _signal_exec { 1672# install a dummy wakeup watcher to reduce signal catching latency
1263 $HAVE_ASYNC_INTERRUPT 1673# used by Impls
1264 ? $SIGPIPE_R->drain 1674sub _sig_add() {
1265 : sysread $SIGPIPE_R, my $dummy, 9; 1675 unless ($SIG_COUNT++) {
1676 # try to align timer on a full-second boundary, if possible
1677 my $NOW = AE::now;
1266 1678
1267 while (%SIG_EV) { 1679 $SIG_TW = AE::timer
1268 for (keys %SIG_EV) { 1680 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1269 delete $SIG_EV{$_}; 1681 $MAX_SIGNAL_LATENCY,
1270 $_->() for values %{ $SIG_CB{$_} || {} }; 1682 sub { } # just for the PERL_ASYNC_CHECK
1271 } 1683 ;
1272 } 1684 }
1273} 1685}
1274 1686
1275sub _signal { 1687sub _sig_del {
1276 my (undef, %arg) = @_;
1277
1278 my $signal = uc $arg{signal}
1279 or Carp::croak "required option 'signal' is missing";
1280
1281 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1282
1283 if ($HAVE_ASYNC_INTERRUPT) {
1284 # async::interrupt
1285
1286 $SIG_ASY{$signal} ||= do {
1287 my $asy = new Async::Interrupt
1288 cb => sub { undef $SIG_EV{$signal} },
1289 signal => $signal,
1290 pipe => [$SIGPIPE_R->filenos],
1291 ;
1292 $asy->pipe_autodrain (0);
1293
1294 $asy
1295 };
1296
1297 } else {
1298 # pure perl
1299
1300 $SIG{$signal} ||= sub {
1301 local $!;
1302 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1303 undef $SIG_EV{$signal};
1304 };
1305
1306 # can't do signal processing without introducing races in pure perl,
1307 # so limit the signal latency.
1308 ++$SIG_COUNT;
1309 $SIG_TW ||= AnyEvent->timer (
1310 after => $MAX_SIGNAL_LATENCY,
1311 interval => $MAX_SIGNAL_LATENCY,
1312 cb => sub { }, # just for the PERL_ASYNC_CHECK
1313 );
1314 }
1315
1316 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1317}
1318
1319sub signal {
1320 # probe for availability of Async::Interrupt
1321 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1322 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1323
1324 $HAVE_ASYNC_INTERRUPT = 1;
1325 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1326 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1327
1328 } else {
1329 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1330
1331 require Fcntl;
1332
1333 if (AnyEvent::WIN32) {
1334 require AnyEvent::Util;
1335
1336 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1337 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1338 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1339 } else {
1340 pipe $SIGPIPE_R, $SIGPIPE_W;
1341 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1342 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1343
1344 # not strictly required, as $^F is normally 2, but let's make sure...
1345 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1346 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1347 }
1348
1349 $SIGPIPE_R
1350 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1351
1352 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1353 }
1354
1355 *signal = \&_signal;
1356 &signal
1357}
1358
1359sub AnyEvent::Base::signal::DESTROY {
1360 my ($signal, $cb) = @{$_[0]};
1361
1362 undef $SIG_TW 1688 undef $SIG_TW
1363 unless --$SIG_COUNT; 1689 unless --$SIG_COUNT;
1690}
1364 1691
1692our $_sig_name_init; $_sig_name_init = sub {
1693 eval q{ # poor man's autoloading {}
1694 undef $_sig_name_init;
1695
1696 if (_have_async_interrupt) {
1697 *sig2num = \&Async::Interrupt::sig2num;
1698 *sig2name = \&Async::Interrupt::sig2name;
1699 } else {
1700 require Config;
1701
1702 my %signame2num;
1703 @signame2num{ split ' ', $Config::Config{sig_name} }
1704 = split ' ', $Config::Config{sig_num};
1705
1706 my @signum2name;
1707 @signum2name[values %signame2num] = keys %signame2num;
1708
1709 *sig2num = sub($) {
1710 $_[0] > 0 ? shift : $signame2num{+shift}
1711 };
1712 *sig2name = sub ($) {
1713 $_[0] > 0 ? $signum2name[+shift] : shift
1714 };
1715 }
1716 };
1717 die if $@;
1718};
1719
1720sub sig2num ($) { &$_sig_name_init; &sig2num }
1721sub sig2name($) { &$_sig_name_init; &sig2name }
1722
1723sub signal {
1724 eval q{ # poor man's autoloading {}
1725 # probe for availability of Async::Interrupt
1726 if (_have_async_interrupt) {
1727 AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1728
1729 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1730 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1731
1732 } else {
1733 AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1734
1735 if (AnyEvent::WIN32) {
1736 require AnyEvent::Util;
1737
1738 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1739 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1740 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1741 } else {
1742 pipe $SIGPIPE_R, $SIGPIPE_W;
1743 fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1744 fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1745
1746 # not strictly required, as $^F is normally 2, but let's make sure...
1747 fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1748 fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1749 }
1750
1751 $SIGPIPE_R
1752 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1753
1754 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1755 }
1756
1757 *signal = $HAVE_ASYNC_INTERRUPT
1758 ? sub {
1759 my (undef, %arg) = @_;
1760
1761 # async::interrupt
1762 my $signal = sig2num $arg{signal};
1763 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1764
1765 $SIG_ASY{$signal} ||= new Async::Interrupt
1766 cb => sub { undef $SIG_EV{$signal} },
1767 signal => $signal,
1768 pipe => [$SIGPIPE_R->filenos],
1769 pipe_autodrain => 0,
1770 ;
1771
1772 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1773 }
1774 : sub {
1775 my (undef, %arg) = @_;
1776
1777 # pure perl
1778 my $signal = sig2name $arg{signal};
1779 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1780
1781 $SIG{$signal} ||= sub {
1782 local $!;
1783 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1784 undef $SIG_EV{$signal};
1785 };
1786
1787 # can't do signal processing without introducing races in pure perl,
1788 # so limit the signal latency.
1789 _sig_add;
1790
1791 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1792 }
1793 ;
1794
1795 *AnyEvent::Base::signal::DESTROY = sub {
1796 my ($signal, $cb) = @{$_[0]};
1797
1798 _sig_del;
1799
1365 delete $SIG_CB{$signal}{$cb}; 1800 delete $SIG_CB{$signal}{$cb};
1366 1801
1802 $HAVE_ASYNC_INTERRUPT
1803 ? delete $SIG_ASY{$signal}
1367 # delete doesn't work with older perls - they then 1804 : # delete doesn't work with older perls - they then
1368 # print weird messages, or just unconditionally exit 1805 # print weird messages, or just unconditionally exit
1369 # instead of getting the default action. 1806 # instead of getting the default action.
1370 undef $SIG{$signal} 1807 undef $SIG{$signal}
1371 unless keys %{ $SIG_CB{$signal} }; 1808 unless keys %{ $SIG_CB{$signal} };
1809 };
1810
1811 *_signal_exec = sub {
1812 $HAVE_ASYNC_INTERRUPT
1813 ? $SIGPIPE_R->drain
1814 : sysread $SIGPIPE_R, (my $dummy), 9;
1815
1816 while (%SIG_EV) {
1817 for (keys %SIG_EV) {
1818 delete $SIG_EV{$_};
1819 &$_ for values %{ $SIG_CB{$_} || {} };
1820 }
1821 }
1822 };
1823 };
1824 die if $@;
1825
1826 &signal
1372} 1827}
1373 1828
1374# default implementation for ->child 1829# default implementation for ->child
1375 1830
1376our %PID_CB; 1831our %PID_CB;
1377our $CHLD_W; 1832our $CHLD_W;
1378our $CHLD_DELAY_W; 1833our $CHLD_DELAY_W;
1379our $WNOHANG;
1380 1834
1381sub _sigchld { 1835# used by many Impl's
1382 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1836sub _emit_childstatus($$) {
1383 $_->($pid, $?) 1837 my (undef, $rpid, $rstatus) = @_;
1838
1839 $_->($rpid, $rstatus)
1384 for values %{ $PID_CB{$pid} || {} }, 1840 for values %{ $PID_CB{$rpid} || {} },
1385 values %{ $PID_CB{0} || {} }; 1841 values %{ $PID_CB{0} || {} };
1386 }
1387} 1842}
1388 1843
1389sub child { 1844sub child {
1845 eval q{ # poor man's autoloading {}
1846 *_sigchld = sub {
1847 my $pid;
1848
1849 AnyEvent->_emit_childstatus ($pid, $?)
1850 while ($pid = waitpid -1, WNOHANG) > 0;
1851 };
1852
1853 *child = sub {
1390 my (undef, %arg) = @_; 1854 my (undef, %arg) = @_;
1391 1855
1392 defined (my $pid = $arg{pid} + 0) 1856 my $pid = $arg{pid};
1393 or Carp::croak "required option 'pid' is missing"; 1857 my $cb = $arg{cb};
1394 1858
1395 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1859 $PID_CB{$pid}{$cb+0} = $cb;
1396 1860
1397 # WNOHANG is almost cetrainly 1 everywhere
1398 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1399 ? 1
1400 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1401
1402 unless ($CHLD_W) { 1861 unless ($CHLD_W) {
1403 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1862 $CHLD_W = AE::signal CHLD => \&_sigchld;
1404 # child could be a zombie already, so make at least one round 1863 # child could be a zombie already, so make at least one round
1405 &_sigchld; 1864 &_sigchld;
1406 } 1865 }
1407 1866
1408 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1867 bless [$pid, $cb+0], "AnyEvent::Base::child"
1409} 1868 };
1410 1869
1411sub AnyEvent::Base::child::DESTROY { 1870 *AnyEvent::Base::child::DESTROY = sub {
1412 my ($pid, $cb) = @{$_[0]}; 1871 my ($pid, $icb) = @{$_[0]};
1413 1872
1414 delete $PID_CB{$pid}{$cb}; 1873 delete $PID_CB{$pid}{$icb};
1415 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1874 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1416 1875
1417 undef $CHLD_W unless keys %PID_CB; 1876 undef $CHLD_W unless keys %PID_CB;
1877 };
1878 };
1879 die if $@;
1880
1881 &child
1418} 1882}
1419 1883
1420# idle emulation is done by simply using a timer, regardless 1884# idle emulation is done by simply using a timer, regardless
1421# of whether the process is idle or not, and not letting 1885# of whether the process is idle or not, and not letting
1422# the callback use more than 50% of the time. 1886# the callback use more than 50% of the time.
1423sub idle { 1887sub idle {
1888 eval q{ # poor man's autoloading {}
1889 *idle = sub {
1424 my (undef, %arg) = @_; 1890 my (undef, %arg) = @_;
1425 1891
1426 my ($cb, $w, $rcb) = $arg{cb}; 1892 my ($cb, $w, $rcb) = $arg{cb};
1427 1893
1428 $rcb = sub { 1894 $rcb = sub {
1429 if ($cb) { 1895 if ($cb) {
1430 $w = _time; 1896 $w = AE::time;
1431 &$cb; 1897 &$cb;
1432 $w = _time - $w; 1898 $w = AE::time - $w;
1433 1899
1434 # never use more then 50% of the time for the idle watcher, 1900 # never use more then 50% of the time for the idle watcher,
1435 # within some limits 1901 # within some limits
1436 $w = 0.0001 if $w < 0.0001; 1902 $w = 0.0001 if $w < 0.0001;
1437 $w = 5 if $w > 5; 1903 $w = 5 if $w > 5;
1438 1904
1439 $w = AnyEvent->timer (after => $w, cb => $rcb); 1905 $w = AE::timer $w, 0, $rcb;
1440 } else { 1906 } else {
1441 # clean up... 1907 # clean up...
1442 undef $w; 1908 undef $w;
1443 undef $rcb; 1909 undef $rcb;
1910 }
1911 };
1912
1913 $w = AE::timer 0.05, 0, $rcb;
1914
1915 bless \\$cb, "AnyEvent::Base::idle"
1444 } 1916 };
1917
1918 *AnyEvent::Base::idle::DESTROY = sub {
1919 undef $${$_[0]};
1920 };
1445 }; 1921 };
1922 die if $@;
1446 1923
1447 $w = AnyEvent->timer (after => 0.05, cb => $rcb); 1924 &idle
1448
1449 bless \\$cb, "AnyEvent::Base::idle"
1450}
1451
1452sub AnyEvent::Base::idle::DESTROY {
1453 undef $${$_[0]};
1454} 1925}
1455 1926
1456package AnyEvent::CondVar; 1927package AnyEvent::CondVar;
1457 1928
1458our @ISA = AnyEvent::CondVar::Base::; 1929our @ISA = AnyEvent::CondVar::Base::;
1930
1931# only to be used for subclassing
1932sub new {
1933 my $class = shift;
1934 bless AnyEvent->condvar (@_), $class
1935}
1459 1936
1460package AnyEvent::CondVar::Base; 1937package AnyEvent::CondVar::Base;
1461 1938
1462#use overload 1939#use overload
1463# '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1940# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1473 1950
1474sub _send { 1951sub _send {
1475 # nop 1952 # nop
1476} 1953}
1477 1954
1955sub _wait {
1956 AnyEvent->_poll until $_[0]{_ae_sent};
1957}
1958
1478sub send { 1959sub send {
1479 my $cv = shift; 1960 my $cv = shift;
1480 $cv->{_ae_sent} = [@_]; 1961 $cv->{_ae_sent} = [@_];
1481 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; 1962 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1482 $cv->_send; 1963 $cv->_send;
1489 1970
1490sub ready { 1971sub ready {
1491 $_[0]{_ae_sent} 1972 $_[0]{_ae_sent}
1492} 1973}
1493 1974
1494sub _wait {
1495 $WAITING
1496 and !$_[0]{_ae_sent}
1497 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1498
1499 local $WAITING = 1;
1500 AnyEvent->one_event while !$_[0]{_ae_sent};
1501}
1502
1503sub recv { 1975sub recv {
1976 unless ($_[0]{_ae_sent}) {
1977 $WAITING
1978 and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
1979
1980 local $WAITING = 1;
1504 $_[0]->_wait; 1981 $_[0]->_wait;
1982 }
1505 1983
1506 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1984 $_[0]{_ae_croak}
1507 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1985 and Carp::croak $_[0]{_ae_croak};
1986
1987 wantarray
1988 ? @{ $_[0]{_ae_sent} }
1989 : $_[0]{_ae_sent}[0]
1508} 1990}
1509 1991
1510sub cb { 1992sub cb {
1511 $_[0]{_ae_cb} = $_[1] if @_ > 1; 1993 my $cv = shift;
1994
1995 @_
1996 and $cv->{_ae_cb} = shift
1997 and $cv->{_ae_sent}
1998 and (delete $cv->{_ae_cb})->($cv);
1999
1512 $_[0]{_ae_cb} 2000 $cv->{_ae_cb}
1513} 2001}
1514 2002
1515sub begin { 2003sub begin {
1516 ++$_[0]{_ae_counter}; 2004 ++$_[0]{_ae_counter};
1517 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 2005 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1522 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; 2010 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1523} 2011}
1524 2012
1525# undocumented/compatibility with pre-3.4 2013# undocumented/compatibility with pre-3.4
1526*broadcast = \&send; 2014*broadcast = \&send;
1527*wait = \&_wait; 2015*wait = \&recv;
1528 2016
1529=head1 ERROR AND EXCEPTION HANDLING 2017=head1 ERROR AND EXCEPTION HANDLING
1530 2018
1531In general, AnyEvent does not do any error handling - it relies on the 2019In general, AnyEvent does not do any error handling - it relies on the
1532caller to do that if required. The L<AnyEvent::Strict> module (see also 2020caller to do that if required. The L<AnyEvent::Strict> module (see also
1544$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and 2032$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1545so on. 2033so on.
1546 2034
1547=head1 ENVIRONMENT VARIABLES 2035=head1 ENVIRONMENT VARIABLES
1548 2036
1549The following environment variables are used by this module or its 2037AnyEvent supports a number of environment variables that tune the
1550submodules. 2038runtime behaviour. They are usually evaluated when AnyEvent is
2039loaded, initialised, or a submodule that uses them is loaded. Many of
2040them also cause AnyEvent to load additional modules - for example,
2041C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
2042loaded.
1551 2043
1552Note that AnyEvent will remove I<all> environment variables starting with 2044All the environment variables documented here start with
1553C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is 2045C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1554enabled. 2046namespace. Other modules are encouraged (but by no means required) to use
2047C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
2048namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
2049be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
2050variables starting with C<AE_>, see below).
2051
2052All variables can also be set via the C<AE_> prefix, that is, instead
2053of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
2054case there is a clash btween anyevent and another program that uses
2055C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
2056variable to the empty string, as those variables take precedence.
2057
2058When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
2059to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
2060exists. If taint mode is on, then AnyEvent will remove I<all> environment
2061variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
2062with C<undef> or the empty string, if the corresaponding C<AE_> variable
2063is set).
2064
2065The exact algorithm is currently:
2066
2067 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
2068 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
2069 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
2070
2071This ensures that child processes will not see the C<AE_> variables.
2072
2073The following environment variables are currently known to AnyEvent:
1555 2074
1556=over 4 2075=over 4
1557 2076
1558=item C<PERL_ANYEVENT_VERBOSE> 2077=item C<PERL_ANYEVENT_VERBOSE>
1559 2078
1560By default, AnyEvent will be completely silent except in fatal 2079By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1561conditions. You can set this environment variable to make AnyEvent more 2080higher (see L<AnyEvent::Log>). You can set this environment variable to a
1562talkative. 2081numerical loglevel to make AnyEvent more (or less) talkative.
1563 2082
2083If you want to do more than just set the global logging level
2084you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
2085complex specifications.
2086
2087When set to C<0> (C<off>), then no messages whatsoever will be logged with
2088everything else at defaults.
2089
1564When set to C<1> or higher, causes AnyEvent to warn about unexpected 2090When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1565conditions, such as not being able to load the event model specified by 2091conditions, such as not being able to load the event model specified by
1566C<PERL_ANYEVENT_MODEL>. 2092C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
2093is the minimum recommended level for use during development.
1567 2094
1568When set to C<2> or higher, cause AnyEvent to report to STDERR which event 2095When set to C<7> or higher (info), AnyEvent reports which event model it
1569model it chooses. 2096chooses.
1570 2097
1571When set to C<8> or higher, then AnyEvent will report extra information on 2098When set to C<8> or higher (debug), then AnyEvent will report extra
1572which optional modules it loads and how it implements certain features. 2099information on which optional modules it loads and how it implements
2100certain features.
2101
2102=item C<PERL_ANYEVENT_LOG>
2103
2104Accepts rather complex logging specifications. For example, you could log
2105all C<debug> messages of some module to stderr, warnings and above to
2106stderr, and errors and above to syslog, with:
2107
2108 PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
2109
2110For the rather extensive details, see L<AnyEvent::Log>.
2111
2112This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
2113so will take effect even before AnyEvent has initialised itself.
2114
2115Note that specifying this environment variable causes the L<AnyEvent::Log>
2116module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
2117using the latter saves a few hundred kB of memory unless a module
2118explicitly needs the extra features of AnyEvent::Log.
1573 2119
1574=item C<PERL_ANYEVENT_STRICT> 2120=item C<PERL_ANYEVENT_STRICT>
1575 2121
1576AnyEvent does not do much argument checking by default, as thorough 2122AnyEvent does not do much argument checking by default, as thorough
1577argument checking is very costly. Setting this variable to a true value 2123argument checking is very costly. Setting this variable to a true value
1579check the arguments passed to most method calls. If it finds any problems, 2125check the arguments passed to most method calls. If it finds any problems,
1580it will croak. 2126it will croak.
1581 2127
1582In other words, enables "strict" mode. 2128In other words, enables "strict" mode.
1583 2129
1584Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense> 2130Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1585>>, it is definitely recommended to keep it off in production. Keeping 2131>>, it is definitely recommended to keep it off in production. Keeping
1586C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs 2132C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1587can be very useful, however. 2133can be very useful, however.
1588 2134
2135=item C<PERL_ANYEVENT_DEBUG_SHELL>
2136
2137If this env variable is nonempty, then its contents will be interpreted by
2138C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
2139replacing every occurance of C<$$> by the process pid). The shell object
2140is saved in C<$AnyEvent::Debug::SHELL>.
2141
2142This happens when the first watcher is created.
2143
2144For example, to bind a debug shell on a unix domain socket in
2145F<< /tmp/debug<pid>.sock >>, you could use this:
2146
2147 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
2148 # connect with e.g.: socat readline /tmp/debug123.sock
2149
2150Or to bind to tcp port 4545 on localhost:
2151
2152 PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
2153 # connect with e.g.: telnet localhost 4545
2154
2155Note that creating sockets in F</tmp> or on localhost is very unsafe on
2156multiuser systems.
2157
2158=item C<PERL_ANYEVENT_DEBUG_WRAP>
2159
2160Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
2161debugging purposes. See C<AnyEvent::Debug::wrap> for details.
2162
1589=item C<PERL_ANYEVENT_MODEL> 2163=item C<PERL_ANYEVENT_MODEL>
1590 2164
1591This can be used to specify the event model to be used by AnyEvent, before 2165This can be used to specify the event model to be used by AnyEvent, before
1592auto detection and -probing kicks in. It must be a string consisting 2166auto detection and -probing kicks in.
1593entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 2167
2168It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
2169or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1594and the resulting module name is loaded and if the load was successful, 2170resulting module name is loaded and - if the load was successful - used as
1595used as event model. If it fails to load AnyEvent will proceed with 2171event model backend. If it fails to load then AnyEvent will proceed with
1596auto detection and -probing. 2172auto detection and -probing.
1597 2173
1598This functionality might change in future versions. 2174If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
2175nothing gets prepended and the module name is used as-is (hint: C<::> at
2176the end of a string designates a module name and quotes it appropriately).
1599 2177
1600For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 2178For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1601could start your program like this: 2179could start your program like this:
1602 2180
1603 PERL_ANYEVENT_MODEL=Perl perl ... 2181 PERL_ANYEVENT_MODEL=Perl perl ...
2182
2183=item C<PERL_ANYEVENT_IO_MODEL>
2184
2185The current file I/O model - see L<AnyEvent::IO> for more info.
2186
2187At the moment, only C<Perl> (small, pure-perl, synchronous) and
2188C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
2189L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1604 2190
1605=item C<PERL_ANYEVENT_PROTOCOLS> 2191=item C<PERL_ANYEVENT_PROTOCOLS>
1606 2192
1607Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences 2193Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1608for IPv4 or IPv6. The default is unspecified (and might change, or be the result 2194for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1621but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 2207but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1622- only support IPv4, never try to resolve or contact IPv6 2208- only support IPv4, never try to resolve or contact IPv6
1623addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 2209addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1624IPv6, but prefer IPv6 over IPv4. 2210IPv6, but prefer IPv6 over IPv4.
1625 2211
2212=item C<PERL_ANYEVENT_HOSTS>
2213
2214This variable, if specified, overrides the F</etc/hosts> file used by
2215L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
2216from that file instead.
2217
1626=item C<PERL_ANYEVENT_EDNS0> 2218=item C<PERL_ANYEVENT_EDNS0>
1627 2219
1628Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension 2220Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1629for DNS. This extension is generally useful to reduce DNS traffic, but 2221DNS. This extension is generally useful to reduce DNS traffic, especially
1630some (broken) firewalls drop such DNS packets, which is why it is off by 2222when DNSSEC is involved, but some (broken) firewalls drop such DNS
1631default. 2223packets, which is why it is off by default.
1632 2224
1633Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 2225Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1634EDNS0 in its DNS requests. 2226EDNS0 in its DNS requests.
1635 2227
1636=item C<PERL_ANYEVENT_MAX_FORKS> 2228=item C<PERL_ANYEVENT_MAX_FORKS>
1642 2234
1643The default value for the C<max_outstanding> parameter for the default DNS 2235The default value for the C<max_outstanding> parameter for the default DNS
1644resolver - this is the maximum number of parallel DNS requests that are 2236resolver - this is the maximum number of parallel DNS requests that are
1645sent to the DNS server. 2237sent to the DNS server.
1646 2238
2239=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
2240
2241Perl has inherently racy signal handling (you can basically choose between
2242losing signals and memory corruption) - pure perl event loops (including
2243C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
2244have to poll regularly to avoid losing signals.
2245
2246Some event loops are racy, but don't poll regularly, and some event loops
2247are written in C but are still racy. For those event loops, AnyEvent
2248installs a timer that regularly wakes up the event loop.
2249
2250By default, the interval for this timer is C<10> seconds, but you can
2251override this delay with this environment variable (or by setting
2252the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
2253watchers).
2254
2255Lower values increase CPU (and energy) usage, higher values can introduce
2256long delays when reaping children or waiting for signals.
2257
2258The L<AnyEvent::Async> module, if available, will be used to avoid this
2259polling (with most event loops).
2260
1647=item C<PERL_ANYEVENT_RESOLV_CONF> 2261=item C<PERL_ANYEVENT_RESOLV_CONF>
1648 2262
1649The file to use instead of F</etc/resolv.conf> (or OS-specific 2263The absolute path to a F<resolv.conf>-style file to use instead of
1650configuration) in the default resolver. When set to the empty string, no 2264F</etc/resolv.conf> (or the OS-specific configuration) in the default
1651default config will be used. 2265resolver, or the empty string to select the default configuration.
1652 2266
1653=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. 2267=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1654 2268
1655When neither C<ca_file> nor C<ca_path> was specified during 2269When neither C<ca_file> nor C<ca_path> was specified during
1656L<AnyEvent::TLS> context creation, and either of these environment 2270L<AnyEvent::TLS> context creation, and either of these environment
1657variables exist, they will be used to specify CA certificate locations 2271variables are nonempty, they will be used to specify CA certificate
1658instead of a system-dependent default. 2272locations instead of a system-dependent default.
1659 2273
1660=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT> 2274=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1661 2275
1662When these are set to C<1>, then the respective modules are not 2276When these are set to C<1>, then the respective modules are not
1663loaded. Mostly good for testing AnyEvent itself. 2277loaded. Mostly good for testing AnyEvent itself.
1726 warn "read: $input\n"; # output what has been read 2340 warn "read: $input\n"; # output what has been read
1727 $cv->send if $input =~ /^q/i; # quit program if /^q/i 2341 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1728 }, 2342 },
1729 ); 2343 );
1730 2344
1731 my $time_watcher; # can only be used once
1732
1733 sub new_timer {
1734 $timer = AnyEvent->timer (after => 1, cb => sub { 2345 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1735 warn "timeout\n"; # print 'timeout' about every second 2346 warn "timeout\n"; # print 'timeout' at most every second
1736 &new_timer; # and restart the time
1737 }); 2347 });
1738 }
1739
1740 new_timer; # create first timer
1741 2348
1742 $cv->recv; # wait until user enters /^q/i 2349 $cv->recv; # wait until user enters /^q/i
1743 2350
1744=head1 REAL-WORLD EXAMPLE 2351=head1 REAL-WORLD EXAMPLE
1745 2352
1818 2425
1819The actual code goes further and collects all errors (C<die>s, exceptions) 2426The actual code goes further and collects all errors (C<die>s, exceptions)
1820that occurred during request processing. The C<result> method detects 2427that occurred during request processing. The C<result> method detects
1821whether an exception as thrown (it is stored inside the $txn object) 2428whether an exception as thrown (it is stored inside the $txn object)
1822and just throws the exception, which means connection errors and other 2429and just throws the exception, which means connection errors and other
1823problems get reported tot he code that tries to use the result, not in a 2430problems get reported to the code that tries to use the result, not in a
1824random callback. 2431random callback.
1825 2432
1826All of this enables the following usage styles: 2433All of this enables the following usage styles:
1827 2434
18281. Blocking: 24351. Blocking:
1876through AnyEvent. The benchmark creates a lot of timers (with a zero 2483through AnyEvent. The benchmark creates a lot of timers (with a zero
1877timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2484timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1878which it is), lets them fire exactly once and destroys them again. 2485which it is), lets them fire exactly once and destroys them again.
1879 2486
1880Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2487Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1881distribution. 2488distribution. It uses the L<AE> interface, which makes a real difference
2489for the EV and Perl backends only.
1882 2490
1883=head3 Explanation of the columns 2491=head3 Explanation of the columns
1884 2492
1885I<watcher> is the number of event watchers created/destroyed. Since 2493I<watcher> is the number of event watchers created/destroyed. Since
1886different event models feature vastly different performances, each event 2494different event models feature vastly different performances, each event
1907watcher. 2515watcher.
1908 2516
1909=head3 Results 2517=head3 Results
1910 2518
1911 name watchers bytes create invoke destroy comment 2519 name watchers bytes create invoke destroy comment
1912 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2520 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1913 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2521 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1914 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2522 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1915 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2523 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1916 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2524 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1917 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2525 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1918 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll 2526 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1919 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll 2527 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1920 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2528 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1921 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2529 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1922 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2530 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1923 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2531 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1924 2532
1925=head3 Discussion 2533=head3 Discussion
1926 2534
1927The benchmark does I<not> measure scalability of the event loop very 2535The benchmark does I<not> measure scalability of the event loop very
1928well. For example, a select-based event loop (such as the pure perl one) 2536well. For example, a select-based event loop (such as the pure perl one)
1940benchmark machine, handling an event takes roughly 1600 CPU cycles with 2548benchmark machine, handling an event takes roughly 1600 CPU cycles with
1941EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2549EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1942cycles with POE. 2550cycles with POE.
1943 2551
1944C<EV> is the sole leader regarding speed and memory use, which are both 2552C<EV> is the sole leader regarding speed and memory use, which are both
1945maximal/minimal, respectively. Even when going through AnyEvent, it uses 2553maximal/minimal, respectively. When using the L<AE> API there is zero
2554overhead (when going through the AnyEvent API create is about 5-6 times
2555slower, with other times being equal, so still uses far less memory than
1946far less memory than any other event loop and is still faster than Event 2556any other event loop and is still faster than Event natively).
1947natively.
1948 2557
1949The pure perl implementation is hit in a few sweet spots (both the 2558The pure perl implementation is hit in a few sweet spots (both the
1950constant timeout and the use of a single fd hit optimisations in the perl 2559constant timeout and the use of a single fd hit optimisations in the perl
1951interpreter and the backend itself). Nevertheless this shows that it 2560interpreter and the backend itself). Nevertheless this shows that it
1952adds very little overhead in itself. Like any select-based backend its 2561adds very little overhead in itself. Like any select-based backend its
2000(even when used without AnyEvent), but most event loops have acceptable 2609(even when used without AnyEvent), but most event loops have acceptable
2001performance with or without AnyEvent. 2610performance with or without AnyEvent.
2002 2611
2003=item * The overhead AnyEvent adds is usually much smaller than the overhead of 2612=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2004the actual event loop, only with extremely fast event loops such as EV 2613the actual event loop, only with extremely fast event loops such as EV
2005adds AnyEvent significant overhead. 2614does AnyEvent add significant overhead.
2006 2615
2007=item * You should avoid POE like the plague if you want performance or 2616=item * You should avoid POE like the plague if you want performance or
2008reasonable memory usage. 2617reasonable memory usage.
2009 2618
2010=back 2619=back
2026In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2635In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2027(1%) are active. This mirrors the activity of large servers with many 2636(1%) are active. This mirrors the activity of large servers with many
2028connections, most of which are idle at any one point in time. 2637connections, most of which are idle at any one point in time.
2029 2638
2030Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2639Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2031distribution. 2640distribution. It uses the L<AE> interface, which makes a real difference
2641for the EV and Perl backends only.
2032 2642
2033=head3 Explanation of the columns 2643=head3 Explanation of the columns
2034 2644
2035I<sockets> is the number of sockets, and twice the number of "servers" (as 2645I<sockets> is the number of sockets, and twice the number of "servers" (as
2036each server has a read and write socket end). 2646each server has a read and write socket end).
2044a new one that moves the timeout into the future. 2654a new one that moves the timeout into the future.
2045 2655
2046=head3 Results 2656=head3 Results
2047 2657
2048 name sockets create request 2658 name sockets create request
2049 EV 20000 69.01 11.16 2659 EV 20000 62.66 7.99
2050 Perl 20000 73.32 35.87 2660 Perl 20000 68.32 32.64
2051 IOAsync 20000 157.00 98.14 epoll 2661 IOAsync 20000 174.06 101.15 epoll
2052 IOAsync 20000 159.31 616.06 poll 2662 IOAsync 20000 174.67 610.84 poll
2053 Event 20000 212.62 257.32 2663 Event 20000 202.69 242.91
2054 Glib 20000 651.16 1896.30 2664 Glib 20000 557.01 1689.52
2055 POE 20000 349.67 12317.24 uses POE::Loop::Event 2665 POE 20000 341.54 12086.32 uses POE::Loop::Event
2056 2666
2057=head3 Discussion 2667=head3 Discussion
2058 2668
2059This benchmark I<does> measure scalability and overall performance of the 2669This benchmark I<does> measure scalability and overall performance of the
2060particular event loop. 2670particular event loop.
2186As you can see, the AnyEvent + EV combination even beats the 2796As you can see, the AnyEvent + EV combination even beats the
2187hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl 2797hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2188backend easily beats IO::Lambda and POE. 2798backend easily beats IO::Lambda and POE.
2189 2799
2190And even the 100% non-blocking version written using the high-level (and 2800And even the 100% non-blocking version written using the high-level (and
2191slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a 2801slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2192large margin, even though it does all of DNS, tcp-connect and socket I/O 2802higher level ("unoptimised") abstractions by a large margin, even though
2193in a non-blocking way. 2803it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2194 2804
2195The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and 2805The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2196F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are 2806F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2197part of the IO::lambda distribution and were used without any changes. 2807part of the IO::Lambda distribution and were used without any changes.
2198 2808
2199 2809
2200=head1 SIGNALS 2810=head1 SIGNALS
2201 2811
2202AnyEvent currently installs handlers for these signals: 2812AnyEvent currently installs handlers for these signals:
2239 unless defined $SIG{PIPE}; 2849 unless defined $SIG{PIPE};
2240 2850
2241=head1 RECOMMENDED/OPTIONAL MODULES 2851=head1 RECOMMENDED/OPTIONAL MODULES
2242 2852
2243One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and 2853One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2244it's built-in modules) are required to use it. 2854its built-in modules) are required to use it.
2245 2855
2246That does not mean that AnyEvent won't take advantage of some additional 2856That does not mean that AnyEvent won't take advantage of some additional
2247modules if they are installed. 2857modules if they are installed.
2248 2858
2249This section epxlains which additional modules will be used, and how they 2859This section explains which additional modules will be used, and how they
2250affect AnyEvent's operetion. 2860affect AnyEvent's operation.
2251 2861
2252=over 4 2862=over 4
2253 2863
2254=item L<Async::Interrupt> 2864=item L<Async::Interrupt>
2255 2865
2256This slightly arcane module is used to implement fast signal handling: To 2866This slightly arcane module is used to implement fast signal handling: To
2257my knowledge, there is no way to do completely race-free and quick 2867my knowledge, there is no way to do completely race-free and quick
2258signal handling in pure perl. To ensure that signals still get 2868signal handling in pure perl. To ensure that signals still get
2259delivered, AnyEvent will start an interval timer to wake up perl (and 2869delivered, AnyEvent will start an interval timer to wake up perl (and
2260catch the signals) with soemd elay (default is 10 seconds, look for 2870catch the signals) with some delay (default is 10 seconds, look for
2261C<$AnyEvent::MAX_SIGNAL_LATENCY>). 2871C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2262 2872
2263If this module is available, then it will be used to implement signal 2873If this module is available, then it will be used to implement signal
2264catching, which means that signals will not be delayed, and the event loop 2874catching, which means that signals will not be delayed, and the event loop
2265will not be interrupted regularly, which is more efficient (And good for 2875will not be interrupted regularly, which is more efficient (and good for
2266battery life on laptops). 2876battery life on laptops).
2267 2877
2268This affects not just the pure-perl event loop, but also other event loops 2878This affects not just the pure-perl event loop, but also other event loops
2269that have no signal handling on their own (e.g. Glib, Tk, Qt). 2879that have no signal handling on their own (e.g. Glib, Tk, Qt).
2880
2881Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
2882and either employ their own workarounds (POE) or use AnyEvent's workaround
2883(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
2884does nothing for those backends.
2270 2885
2271=item L<EV> 2886=item L<EV>
2272 2887
2273This module isn't really "optional", as it is simply one of the backend 2888This module isn't really "optional", as it is simply one of the backend
2274event loops that AnyEvent can use. However, it is simply the best event 2889event loops that AnyEvent can use. However, it is simply the best event
2277automatic timer adjustments even when no monotonic clock is available, 2892automatic timer adjustments even when no monotonic clock is available,
2278can take avdantage of advanced kernel interfaces such as C<epoll> and 2893can take avdantage of advanced kernel interfaces such as C<epoll> and
2279C<kqueue>, and is the fastest backend I<by far>. You can even embed 2894C<kqueue>, and is the fastest backend I<by far>. You can even embed
2280L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>). 2895L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2281 2896
2897If you only use backends that rely on another event loop (e.g. C<Tk>),
2898then this module will do nothing for you.
2899
2282=item L<Guard> 2900=item L<Guard>
2283 2901
2284The guard module, when used, will be used to implement 2902The guard module, when used, will be used to implement
2285C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a 2903C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2286lot less memory), but otherwise doesn't affect guard operation much. It is 2904lot less memory), but otherwise doesn't affect guard operation much. It is
2287purely used for performance. 2905purely used for performance.
2288 2906
2289=item L<JSON> and L<JSON::XS> 2907=item L<JSON> and L<JSON::XS>
2290 2908
2291This module is required when you want to read or write JSON data via 2909One of these modules is required when you want to read or write JSON data
2292L<AnyEvent::Handle>. It is also written in pure-perl, but can take 2910via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2293advantage of the ulta-high-speed L<JSON::XS> module when it is installed. 2911advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2294
2295In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2296installed.
2297 2912
2298=item L<Net::SSLeay> 2913=item L<Net::SSLeay>
2299 2914
2300Implementing TLS/SSL in Perl is certainly interesting, but not very 2915Implementing TLS/SSL in Perl is certainly interesting, but not very
2301worthwhile: If this module is installed, then L<AnyEvent::Handle> (with 2916worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2302the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL. 2917the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2303 2918
2304=item L<Time::HiRes> 2919=item L<Time::HiRes>
2305 2920
2306This module is part of perl since release 5.008. It will be used when the 2921This module is part of perl since release 5.008. It will be used when the
2307chosen event library does not come with a timing source on it's own. The 2922chosen event library does not come with a timing source of its own. The
2308pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to 2923pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2309try to use a monotonic clock for timing stability. 2924try to use a monotonic clock for timing stability.
2310 2925
2311=back 2926=back
2312 2927
2313 2928
2314=head1 FORK 2929=head1 FORK
2315 2930
2316Most event libraries are not fork-safe. The ones who are usually are 2931Most event libraries are not fork-safe. The ones who are usually are
2317because they rely on inefficient but fork-safe C<select> or C<poll> 2932because they rely on inefficient but fork-safe C<select> or C<poll> calls
2318calls. Only L<EV> is fully fork-aware. 2933- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2934are usually badly thought-out hacks that are incompatible with fork in
2935one way or another. Only L<EV> is fully fork-aware and ensures that you
2936continue event-processing in both parent and child (or both, if you know
2937what you are doing).
2938
2939This means that, in general, you cannot fork and do event processing in
2940the child if the event library was initialised before the fork (which
2941usually happens when the first AnyEvent watcher is created, or the library
2942is loaded).
2319 2943
2320If you have to fork, you must either do so I<before> creating your first 2944If you have to fork, you must either do so I<before> creating your first
2321watcher OR you must not use AnyEvent at all in the child OR you must do 2945watcher OR you must not use AnyEvent at all in the child OR you must do
2322something completely out of the scope of AnyEvent. 2946something completely out of the scope of AnyEvent.
2947
2948The problem of doing event processing in the parent I<and> the child
2949is much more complicated: even for backends that I<are> fork-aware or
2950fork-safe, their behaviour is not usually what you want: fork clones all
2951watchers, that means all timers, I/O watchers etc. are active in both
2952parent and child, which is almost never what you want. USing C<exec>
2953to start worker children from some kind of manage rprocess is usually
2954preferred, because it is much easier and cleaner, at the expense of having
2955to have another binary.
2323 2956
2324 2957
2325=head1 SECURITY CONSIDERATIONS 2958=head1 SECURITY CONSIDERATIONS
2326 2959
2327AnyEvent can be forced to load any event model via 2960AnyEvent can be forced to load any event model via
2357pronounced). 2990pronounced).
2358 2991
2359 2992
2360=head1 SEE ALSO 2993=head1 SEE ALSO
2361 2994
2362Utility functions: L<AnyEvent::Util>. 2995Tutorial/Introduction: L<AnyEvent::Intro>.
2363 2996
2364Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 2997FAQ: L<AnyEvent::FAQ>.
2365L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2998
2999Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
3000(simply logging).
3001
3002Development/Debugging: L<AnyEvent::Strict> (stricter checking),
3003L<AnyEvent::Debug> (interactive shell, watcher tracing).
3004
3005Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
3006L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
3007L<Qt>, L<POE>, L<FLTK>.
2366 3008
2367Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 3009Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2368L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 3010L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2369L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 3011L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2370L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>. 3012L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
3013L<AnyEvent::Impl::FLTK>.
2371 3014
2372Non-blocking file handles, sockets, TCP clients and 3015Non-blocking handles, pipes, stream sockets, TCP clients and
2373servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 3016servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2374 3017
3018Asynchronous File I/O: L<AnyEvent::IO>.
3019
2375Asynchronous DNS: L<AnyEvent::DNS>. 3020Asynchronous DNS: L<AnyEvent::DNS>.
2376 3021
2377Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, 3022Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2378L<Coro::Event>,
2379 3023
2380Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>, 3024Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2381L<AnyEvent::HTTP>. 3025L<AnyEvent::HTTP>.
2382 3026
2383 3027
2384=head1 AUTHOR 3028=head1 AUTHOR
2385 3029
2386 Marc Lehmann <schmorp@schmorp.de> 3030 Marc Lehmann <schmorp@schmorp.de>
2387 http://home.schmorp.de/ 3031 http://anyevent.schmorp.de
2388 3032
2389=cut 3033=cut
2390 3034
23911 30351
2392 3036

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