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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
372 407
373Example: exit on SIGINT 408Example: exit on SIGINT
374 409
375 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 410 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
376 411
412=head3 Restart Behaviour
413
414While restart behaviour is up to the event loop implementation, most will
415not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
416pure perl implementation).
417
418=head3 Safe/Unsafe Signals
419
420Perl signals can be either "safe" (synchronous to opcode handling)
421or "unsafe" (asynchronous) - the former might delay signal delivery
422indefinitely, the latter might corrupt your memory.
423
424AnyEvent signal handlers are, in addition, synchronous to the event loop,
425i.e. they will not interrupt your running perl program but will only be
426called as part of the normal event handling (just like timer, I/O etc.
427callbacks, too).
428
377=head3 Signal Races, Delays and Workarounds 429=head3 Signal Races, Delays and Workarounds
378 430
379Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching 431Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
380callbacks to signals in a generic way, which is a pity, as you cannot do 432attaching callbacks to signals in a generic way, which is a pity,
381race-free signal handling in perl. AnyEvent will try to do it's best, but 433as you cannot do race-free signal handling in perl, requiring
434C libraries for this. AnyEvent will try to do its best, which
382in some cases, signals will be delayed. The maximum time a signal might 435means in some cases, signals will be delayed. The maximum time
383be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 436a signal might be delayed is 10 seconds by default, but can
384seconds). This variable can be changed only before the first signal 437be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
385watcher is created, and should be left alone otherwise. Higher values 438C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
386will cause fewer spurious wake-ups, which is better for power and CPU 439section for details.
440
387saving. All these problems can be avoided by installing the optional 441All these problems can be avoided by installing the optional
388L<Async::Interrupt> module. This will not work with inherently broken 442L<Async::Interrupt> module, which works with most event loops. It will not
389event loops such as L<Event> or L<Event::Lib> (and not with L<POE> 443work with inherently broken event loops such as L<Event> or L<Event::Lib>
390currently, as POE does it's own workaround with one-second latency). With 444(and not with L<POE> currently). For those, you just have to suffer the
391those, you just have to suffer the delays. 445delays.
392 446
393=head2 CHILD PROCESS WATCHERS 447=head2 CHILD PROCESS WATCHERS
394 448
449 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
450
395You 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.
396 452
397The 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,
398watches for any child process exit). The watcher will triggered only when 454using C<0> watches for any child process exit, on others this will
399the child process has finished and an exit status is available, not on 455croak). The watcher will be triggered only when the child process has
400any trace events (stopped/continued). 456finished and an exit status is available, not on any trace events
457(stopped/continued).
401 458
402The 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
403waitpid), 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
404callback arguments. 461callback arguments.
405 462
423thing 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
424watcher before you C<fork> the child (alternatively, you can call 481watcher before you C<fork> the child (alternatively, you can call
425C<AnyEvent::detect>). 482C<AnyEvent::detect>).
426 483
427As 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
428emulated 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
429mentioned in the description of signal watchers apply. 486problems mentioned in the description of signal watchers apply.
430 487
431Example: fork a process and wait for it 488Example: fork a process and wait for it
432 489
433 my $done = AnyEvent->condvar; 490 my $done = AnyEvent->condvar;
434 491
446 # do something else, then wait for process exit 503 # do something else, then wait for process exit
447 $done->recv; 504 $done->recv;
448 505
449=head2 IDLE WATCHERS 506=head2 IDLE WATCHERS
450 507
451Sometimes there is a need to do something, but it is not so important 508 $w = AnyEvent->idle (cb => <callback>);
452to do it instantly, but only when there is nothing better to do. This
453"nothing better to do" is usually defined to be "no other events need
454attention by the event loop".
455 509
456Idle watchers ideally get invoked when the event loop has nothing 510This will repeatedly invoke the callback after the process becomes idle,
457better 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.
458events. Instead of blocking, the idle watcher is invoked.
459 512
460Most 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
461EV, 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
462will simply call the callback "from time to time". 524will simply call the callback "from time to time".
463 525
464Example: read lines from STDIN, but only process them when the 526Example: read lines from STDIN, but only process them when the
465program is otherwise idle: 527program is otherwise idle:
481 }); 543 });
482 }); 544 });
483 545
484=head2 CONDITION VARIABLES 546=head2 CONDITION VARIABLES
485 547
548 $cv = AnyEvent->condvar;
549
550 $cv->send (<list>);
551 my @res = $cv->recv;
552
486If 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
487require you to run some blocking "loop", "run" or similar function that 554require you to run some blocking "loop", "run" or similar function that
488will actively watch for new events and call your callbacks. 555will actively watch for new events and call your callbacks.
489 556
490AnyEvent is slightly different: it expects somebody else to run the event 557AnyEvent is slightly different: it expects somebody else to run the event
491loop 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).
492 559
493The instrument to do that is called a "condition variable", so called 560The tool to do that is called a "condition variable", so called because
494because they represent a condition that must become true. 561they represent a condition that must become true.
495 562
496Now 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.
497 564
498Condition variables can be created by calling the C<< AnyEvent->condvar 565Condition variables can be created by calling the C<< AnyEvent->condvar
499>> method, usually without arguments. The only argument pair allowed is 566>> method, usually without arguments. The only argument pair allowed is
504After creation, the condition variable is "false" until it becomes "true" 571After creation, the condition variable is "false" until it becomes "true"
505by 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
506were 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<<
507->send >> method). 574->send >> method).
508 575
509Condition variables are similar to callbacks, except that you can 576Since condition variables are the most complex part of the AnyEvent API, here are
510optionally 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:
511in time where multiple outstanding events have been processed. And yet 578
512another way to call them is transactions - each condition variable can be 579=over 4
513used to represent a transaction, which finishes at some point and delivers 580
514a 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
515 599
516Condition variables are very useful to signal that something has finished, 600Condition variables are very useful to signal that something has finished,
517for example, if you write a module that does asynchronous http requests, 601for example, if you write a module that does asynchronous http requests,
518then a condition variable would be the ideal candidate to signal the 602then a condition variable would be the ideal candidate to signal the
519availability of results. The user can either act when the callback is 603availability of results. The user can either act when the callback is
532 616
533Condition variables are represented by hash refs in perl, and the keys 617Condition variables are represented by hash refs in perl, and the keys
534used 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
535easy (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
536AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call 620AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
537it's C<new> method in your own C<new> method. 621its C<new> method in your own C<new> method.
538 622
539There are two "sides" to a condition variable - the "producer side" which 623There are two "sides" to a condition variable - the "producer side" which
540eventually calls C<< -> send >>, and the "consumer side", which waits 624eventually calls C<< -> send >>, and the "consumer side", which waits
541for the send to occur. 625for the send to occur.
542 626
543Example: wait for a timer. 627Example: wait for a timer.
544 628
545 # wait till the result is ready 629 # condition: "wait till the timer is fired"
546 my $result_ready = AnyEvent->condvar; 630 my $timer_fired = AnyEvent->condvar;
547 631
548 # do something such as adding a timer 632 # create the timer - we could wait for, say
549 # or socket watcher the calls $result_ready->send 633 # a handle becomign ready, or even an
550 # when the "result" is ready. 634 # AnyEvent::HTTP request to finish, but
551 # in this case, we simply use a timer: 635 # in this case, we simply use a timer:
552 my $w = AnyEvent->timer ( 636 my $w = AnyEvent->timer (
553 after => 1, 637 after => 1,
554 cb => sub { $result_ready->send }, 638 cb => sub { $timer_fired->send },
555 ); 639 );
556 640
557 # this "blocks" (while handling events) till the callback 641 # this "blocks" (while handling events) till the callback
558 # calls -<send 642 # calls ->send
559 $result_ready->recv; 643 $timer_fired->recv;
560 644
561Example: 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
562variables are also callable directly. 646variables are also callable directly.
563 647
564 my $done = AnyEvent->condvar; 648 my $done = AnyEvent->condvar;
607they 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
608C<send>. 692C<send>.
609 693
610=item $cv->croak ($error) 694=item $cv->croak ($error)
611 695
612Similar to send, but causes all call's to C<< ->recv >> to invoke 696Similar to send, but causes all calls to C<< ->recv >> to invoke
613C<Carp::croak> with the given error message/object/scalar. 697C<Carp::croak> with the given error message/object/scalar.
614 698
615This can be used to signal any errors to the condition variable 699This can be used to signal any errors to the condition variable
616user/consumer. Doing it this way instead of calling C<croak> directly 700user/consumer. Doing it this way instead of calling C<croak> directly
617delays the error detetcion, but has the overwhelmign advantage that it 701delays the error detection, but has the overwhelming advantage that it
618diagnoses 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
619deep in some event clalback without connection to the actual code causing 703deep in some event callback with no connection to the actual code causing
620the problem. 704the problem.
621 705
622=item $cv->begin ([group callback]) 706=item $cv->begin ([group callback])
623 707
624=item $cv->end 708=item $cv->end
627one. 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
628to use a condition variable for the whole process. 712to use a condition variable for the whole process.
629 713
630Every 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
631C<< ->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
632>>, 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
633is 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
634callback 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.
635 720
636You 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
637sends), 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
638condition (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).
639 724
661one 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
662sending. 747sending.
663 748
664The ping example mentioned above is slightly more complicated, as the 749The ping example mentioned above is slightly more complicated, as the
665there 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
666begung can potentially be zero: 751begun can potentially be zero:
667 752
668 my $cv = AnyEvent->condvar; 753 my $cv = AnyEvent->condvar;
669 754
670 my %result; 755 my %result;
671 $cv->begin (sub { $cv->send (\%result) }); 756 $cv->begin (sub { shift->send (\%result) });
672 757
673 for my $host (@list_of_hosts) { 758 for my $host (@list_of_hosts) {
674 $cv->begin; 759 $cv->begin;
675 ping_host_then_call_callback $host, sub { 760 ping_host_then_call_callback $host, sub {
676 $result{$host} = ...; 761 $result{$host} = ...;
678 }; 763 };
679 } 764 }
680 765
681 $cv->end; 766 $cv->end;
682 767
768 ...
769
770 my $results = $cv->recv;
771
683This code fragment supposedly pings a number of hosts and calls 772This code fragment supposedly pings a number of hosts and calls
684C<send> after results for all then have have been gathered - in any 773C<send> after results for all then have have been gathered - in any
685order. To achieve this, the code issues a call to C<begin> when it starts 774order. To achieve this, the code issues a call to C<begin> when it starts
686each ping request and calls C<end> when it has received some result for 775each ping request and calls C<end> when it has received some result for
687it. Since C<begin> and C<end> only maintain a counter, the order in which 776it. Since C<begin> and C<end> only maintain a counter, the order in which
692to be called once the counter reaches C<0>, and second, it ensures that 781to be called once the counter reaches C<0>, and second, it ensures that
693C<send> is called even when C<no> hosts are being pinged (the loop 782C<send> is called even when C<no> hosts are being pinged (the loop
694doesn't execute once). 783doesn't execute once).
695 784
696This is the general pattern when you "fan out" into multiple (but 785This is the general pattern when you "fan out" into multiple (but
697potentially none) subrequests: use an outer C<begin>/C<end> pair to set 786potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
698the callback and ensure C<end> is called at least once, and then, for each 787the callback and ensure C<end> is called at least once, and then, for each
699subrequest you start, call C<begin> and for each subrequest you finish, 788subrequest you start, call C<begin> and for each subrequest you finish,
700call C<end>. 789call C<end>.
701 790
702=back 791=back
709=over 4 798=over 4
710 799
711=item $cv->recv 800=item $cv->recv
712 801
713Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 802Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
714>> methods have been called on c<$cv>, while servicing other watchers 803>> methods have been called on C<$cv>, while servicing other watchers
715normally. 804normally.
716 805
717You can only wait once on a condition - additional calls are valid but 806You can only wait once on a condition - additional calls are valid but
718will return immediately. 807will return immediately.
719 808
722 811
723In list context, all parameters passed to C<send> will be returned, 812In list context, all parameters passed to C<send> will be returned,
724in scalar context only the first one will be returned. 813in scalar context only the first one will be returned.
725 814
726Note that doing a blocking wait in a callback is not supported by any 815Note that doing a blocking wait in a callback is not supported by any
727event loop, that is, recursive invocation of a blocking C<< ->recv 816event loop, that is, recursive invocation of a blocking C<< ->recv >> is
728>> is not allowed, and the C<recv> call will C<croak> if such a 817not allowed and the C<recv> call will C<croak> if such a condition is
729condition is detected. This condition can be slightly loosened by using 818detected. This requirement can be dropped by relying on L<Coro::AnyEvent>
730L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from 819, which allows you to do a blocking C<< ->recv >> from any thread
731any thread that doesn't run the event loop itself. 820that doesn't run the event loop itself. L<Coro::AnyEvent> is loaded
821automatically when L<Coro> is used with L<AnyEvent>, so code does not need
822to do anything special to take advantage of that: any code that would
823normally block your program because it calls C<recv>, be executed in an
824C<async> thread instead without blocking other threads.
732 825
733Not all event models support a blocking wait - some die in that case 826Not all event models support a blocking wait - some die in that case
734(programs might want to do that to stay interactive), so I<if you are 827(programs might want to do that to stay interactive), so I<if you are
735using this from a module, never require a blocking wait>. Instead, let the 828using this from a module, never require a blocking wait>. Instead, let the
736caller decide whether the call will block or not (for example, by coupling 829caller decide whether the call will block or not (for example, by coupling
737condition variables with some kind of request results and supporting 830condition variables with some kind of request results and supporting
738callbacks so the caller knows that getting the result will not block, 831callbacks so the caller knows that getting the result will not block,
739while still supporting blocking waits if the caller so desires). 832while still supporting blocking waits if the caller so desires).
740 833
741You can ensure that C<< -recv >> never blocks by setting a callback and 834You can ensure that C<< ->recv >> never blocks by setting a callback and
742only calling C<< ->recv >> from within that callback (or at a later 835only calling C<< ->recv >> from within that callback (or at a later
743time). This will work even when the event loop does not support blocking 836time). This will work even when the event loop does not support blocking
744waits otherwise. 837waits otherwise.
745 838
746=item $bool = $cv->ready 839=item $bool = $cv->ready
752 845
753This is a mutator function that returns the callback set and optionally 846This is a mutator function that returns the callback set and optionally
754replaces it before doing so. 847replaces it before doing so.
755 848
756The callback will be called when the condition becomes "true", i.e. when 849The callback will be called when the condition becomes "true", i.e. when
757C<send> or C<croak> are called, with the only argument being the condition 850C<send> or C<croak> are called, with the only argument being the
758variable itself. Calling C<recv> inside the callback or at any later time 851condition variable itself. If the condition is already true, the
759is guaranteed not to block. 852callback is called immediately when it is set. Calling C<recv> inside
853the callback or at any later time is guaranteed not to block.
760 854
761=back 855=back
762 856
763=head1 SUPPORTED EVENT LOOPS/BACKENDS 857=head1 SUPPORTED EVENT LOOPS/BACKENDS
764 858
767=over 4 861=over 4
768 862
769=item Backends that are autoprobed when no other event loop can be found. 863=item Backends that are autoprobed when no other event loop can be found.
770 864
771EV is the preferred backend when no other event loop seems to be in 865EV is the preferred backend when no other event loop seems to be in
772use. If EV is not installed, then AnyEvent will try Event, and, failing 866use. If EV is not installed, then AnyEvent will fall back to its own
773that, will fall back to its own pure-perl implementation, which is 867pure-perl implementation, which is available everywhere as it comes with
774available everywhere as it comes with AnyEvent itself. 868AnyEvent itself.
775 869
776 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 870 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
777 AnyEvent::Impl::Event based on Event, very stable, few glitches.
778 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 871 AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
779 872
780=item Backends that are transparently being picked up when they are used. 873=item Backends that are transparently being picked up when they are used.
781 874
782These will be used when they are currently loaded when the first watcher 875These will be used if they are already loaded when the first watcher
783is created, in which case it is assumed that the application is using 876is created, in which case it is assumed that the application is using
784them. This means that AnyEvent will automatically pick the right backend 877them. This means that AnyEvent will automatically pick the right backend
785when the main program loads an event module before anything starts to 878when the main program loads an event module before anything starts to
786create watchers. Nothing special needs to be done by the main program. 879create watchers. Nothing special needs to be done by the main program.
787 880
881 AnyEvent::Impl::Event based on Event, very stable, few glitches.
788 AnyEvent::Impl::Glib based on Glib, slow but very stable. 882 AnyEvent::Impl::Glib based on Glib, slow but very stable.
789 AnyEvent::Impl::Tk based on Tk, very broken. 883 AnyEvent::Impl::Tk based on Tk, very broken.
790 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 884 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
791 AnyEvent::Impl::POE based on POE, very slow, some limitations. 885 AnyEvent::Impl::POE based on POE, very slow, some limitations.
886 AnyEvent::Impl::Irssi used when running within irssi.
887 AnyEvent::Impl::IOAsync based on IO::Async.
888 AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
889 AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
792 890
793=item Backends with special needs. 891=item Backends with special needs.
794 892
795Qt requires the Qt::Application to be instantiated first, but will 893Qt requires the Qt::Application to be instantiated first, but will
796otherwise be picked up automatically. As long as the main program 894otherwise be picked up automatically. As long as the main program
797instantiates the application before any AnyEvent watchers are created, 895instantiates the application before any AnyEvent watchers are created,
798everything should just work. 896everything should just work.
799 897
800 AnyEvent::Impl::Qt based on Qt. 898 AnyEvent::Impl::Qt based on Qt.
801 899
802Support for IO::Async can only be partial, as it is too broken and
803architecturally limited to even support the AnyEvent API. It also
804is the only event loop that needs the loop to be set explicitly, so
805it can only be used by a main program knowing about AnyEvent. See
806L<AnyEvent::Impl::Async> for the gory details.
807
808 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
809
810=item Event loops that are indirectly supported via other backends. 900=item Event loops that are indirectly supported via other backends.
811 901
812Some event loops can be supported via other modules: 902Some event loops can be supported via other modules:
813 903
814There is no direct support for WxWidgets (L<Wx>) or L<Prima>. 904There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
839Contains C<undef> until the first watcher is being created, before the 929Contains C<undef> until the first watcher is being created, before the
840backend has been autodetected. 930backend has been autodetected.
841 931
842Afterwards it contains the event model that is being used, which is the 932Afterwards it contains the event model that is being used, which is the
843name of the Perl class implementing the model. This class is usually one 933name of the Perl class implementing the model. This class is usually one
844of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the 934of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
845case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it 935case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
846will be C<urxvt::anyevent>). 936will be C<urxvt::anyevent>).
847 937
848=item AnyEvent::detect 938=item AnyEvent::detect
849 939
850Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 940Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
851if necessary. You should only call this function right before you would 941if necessary. You should only call this function right before you would
852have created an AnyEvent watcher anyway, that is, as late as possible at 942have created an AnyEvent watcher anyway, that is, as late as possible at
853runtime, and not e.g. while initialising of your module. 943runtime, and not e.g. during initialisation of your module.
944
945The effect of calling this function is as if a watcher had been created
946(specifically, actions that happen "when the first watcher is created"
947happen when calling detetc as well).
854 948
855If you need to do some initialisation before AnyEvent watchers are 949If you need to do some initialisation before AnyEvent watchers are
856created, use C<post_detect>. 950created, use C<post_detect>.
857 951
858=item $guard = AnyEvent::post_detect { BLOCK } 952=item $guard = AnyEvent::post_detect { BLOCK }
859 953
860Arranges for the code block to be executed as soon as the event model is 954Arranges for the code block to be executed as soon as the event model is
861autodetected (or immediately if this has already happened). 955autodetected (or immediately if that has already happened).
862 956
863The block will be executed I<after> the actual backend has been detected 957The block will be executed I<after> the actual backend has been detected
864(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been 958(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
865created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do 959created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
866other initialisations - see the sources of L<AnyEvent::Strict> or 960other initialisations - see the sources of L<AnyEvent::Strict> or
870event module detection too early, for example, L<AnyEvent::AIO> creates 964event module detection too early, for example, L<AnyEvent::AIO> creates
871and installs the global L<IO::AIO> watcher in a C<post_detect> block to 965and installs the global L<IO::AIO> watcher in a C<post_detect> block to
872avoid autodetecting the event module at load time. 966avoid autodetecting the event module at load time.
873 967
874If called in scalar or list context, then it creates and returns an object 968If called in scalar or list context, then it creates and returns an object
875that automatically removes the callback again when it is destroyed. See 969that automatically removes the callback again when it is destroyed (or
970C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
876L<Coro::BDB> for a case where this is useful. 971a case where this is useful.
972
973Example: Create a watcher for the IO::AIO module and store it in
974C<$WATCHER>, but do so only do so after the event loop is initialised.
975
976 our WATCHER;
977
978 my $guard = AnyEvent::post_detect {
979 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
980 };
981
982 # the ||= is important in case post_detect immediately runs the block,
983 # as to not clobber the newly-created watcher. assigning both watcher and
984 # post_detect guard to the same variable has the advantage of users being
985 # able to just C<undef $WATCHER> if the watcher causes them grief.
986
987 $WATCHER ||= $guard;
877 988
878=item @AnyEvent::post_detect 989=item @AnyEvent::post_detect
879 990
880If there are any code references in this array (you can C<push> to it 991If there are any code references in this array (you can C<push> to it
881before or after loading AnyEvent), then they will called directly after 992before or after loading AnyEvent), then they will be called directly
882the event loop has been chosen. 993after the event loop has been chosen.
883 994
884You should check C<$AnyEvent::MODEL> before adding to this array, though: 995You should check C<$AnyEvent::MODEL> before adding to this array, though:
885if it is defined then the event loop has already been detected, and the 996if it is defined then the event loop has already been detected, and the
886array will be ignored. 997array will be ignored.
887 998
888Best use C<AnyEvent::post_detect { BLOCK }> when your application allows 999Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
889it,as it takes care of these details. 1000it, as it takes care of these details.
890 1001
891This variable is mainly useful for modules that can do something useful 1002This variable is mainly useful for modules that can do something useful
892when AnyEvent is used and thus want to know when it is initialised, but do 1003when AnyEvent is used and thus want to know when it is initialised, but do
893not need to even load it by default. This array provides the means to hook 1004not need to even load it by default. This array provides the means to hook
894into AnyEvent passively, without loading it. 1005into AnyEvent passively, without loading it.
895 1006
1007Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
1008together, you could put this into Coro (this is the actual code used by
1009Coro to accomplish this):
1010
1011 if (defined $AnyEvent::MODEL) {
1012 # AnyEvent already initialised, so load Coro::AnyEvent
1013 require Coro::AnyEvent;
1014 } else {
1015 # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
1016 # as soon as it is
1017 push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
1018 }
1019
1020=item AnyEvent::postpone { BLOCK }
1021
1022Arranges for the block to be executed as soon as possible, but not before
1023the call itself returns. In practise, the block will be executed just
1024before the event loop polls for new events, or shortly afterwards.
1025
1026This function never returns anything (to make the C<return postpone { ...
1027}> idiom more useful.
1028
1029To understand the usefulness of this function, consider a function that
1030asynchronously does something for you and returns some transaction
1031object or guard to let you cancel the operation. For example,
1032C<AnyEvent::Socket::tcp_connect>:
1033
1034 # start a conenction attempt unless one is active
1035 $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
1036 delete $self->{connect_guard};
1037 ...
1038 };
1039
1040Imagine that this function could instantly call the callback, for
1041example, because it detects an obvious error such as a negative port
1042number. Invoking the callback before the function returns causes problems
1043however: the callback will be called and will try to delete the guard
1044object. But since the function hasn't returned yet, there is nothing to
1045delete. When the function eventually returns it will assign the guard
1046object to C<< $self->{connect_guard} >>, where it will likely never be
1047deleted, so the program thinks it is still trying to connect.
1048
1049This is where C<AnyEvent::postpone> should be used. Instead of calling the
1050callback directly on error:
1051
1052 $cb->(undef), return # signal error to callback, BAD!
1053 if $some_error_condition;
1054
1055It should use C<postpone>:
1056
1057 AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
1058 if $some_error_condition;
1059
1060=item AnyEvent::log $level, $msg[, @args]
1061
1062Log the given C<$msg> at the given C<$level>.
1063
1064If L<AnyEvent::Log> is not loaded then this function makes a simple test
1065to see whether the message will be logged. If the test succeeds it will
1066load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
1067the L<AnyEvent::Log> documentation for details.
1068
1069If the test fails it will simply return. Right now this happens when a
1070numerical loglevel is used and it is larger than the level specified via
1071C<$ENV{PERL_ANYEVENT_VERBOSE}>.
1072
1073If you want to sprinkle loads of logging calls around your code, consider
1074creating a logger callback with the C<AnyEvent::Log::logger> function,
1075which can reduce typing, codesize and can reduce the logging overhead
1076enourmously.
1077
896=back 1078=back
897 1079
898=head1 WHAT TO DO IN A MODULE 1080=head1 WHAT TO DO IN A MODULE
899 1081
900As a module author, you should C<use AnyEvent> and call AnyEvent methods 1082As a module author, you should C<use AnyEvent> and call AnyEvent methods
910because it will stall the whole program, and the whole point of using 1092because it will stall the whole program, and the whole point of using
911events is to stay interactive. 1093events is to stay interactive.
912 1094
913It is fine, however, to call C<< ->recv >> when the user of your module 1095It is fine, however, to call C<< ->recv >> when the user of your module
914requests it (i.e. if you create a http request object ad have a method 1096requests it (i.e. if you create a http request object ad have a method
915called C<results> that returns the results, it should call C<< ->recv >> 1097called C<results> that returns the results, it may call C<< ->recv >>
916freely, as the user of your module knows what she is doing. always). 1098freely, as the user of your module knows what she is doing. Always).
917 1099
918=head1 WHAT TO DO IN THE MAIN PROGRAM 1100=head1 WHAT TO DO IN THE MAIN PROGRAM
919 1101
920There will always be a single main program - the only place that should 1102There will always be a single main program - the only place that should
921dictate which event model to use. 1103dictate which event model to use.
922 1104
923If it doesn't care, it can just "use AnyEvent" and use it itself, or not 1105If the program is not event-based, it need not do anything special, even
924do anything special (it does not need to be event-based) and let AnyEvent 1106when it depends on a module that uses an AnyEvent. If the program itself
925decide which implementation to chose if some module relies on it. 1107uses AnyEvent, but does not care which event loop is used, all it needs
1108to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
1109available loop implementation.
926 1110
927If the main program relies on a specific event model - for example, in 1111If the main program relies on a specific event model - for example, in
928Gtk2 programs you have to rely on the Glib module - you should load the 1112Gtk2 programs you have to rely on the Glib module - you should load the
929event module before loading AnyEvent or any module that uses it: generally 1113event module before loading AnyEvent or any module that uses it: generally
930speaking, you should load it as early as possible. The reason is that 1114speaking, you should load it as early as possible. The reason is that
931modules might create watchers when they are loaded, and AnyEvent will 1115modules might create watchers when they are loaded, and AnyEvent will
932decide on the event model to use as soon as it creates watchers, and it 1116decide on the event model to use as soon as it creates watchers, and it
933might chose the wrong one unless you load the correct one yourself. 1117might choose the wrong one unless you load the correct one yourself.
934 1118
935You can chose to use a pure-perl implementation by loading the 1119You can chose to use a pure-perl implementation by loading the
936C<AnyEvent::Impl::Perl> module, which gives you similar behaviour 1120C<AnyEvent::Loop> module, which gives you similar behaviour
937everywhere, but letting AnyEvent chose the model is generally better. 1121everywhere, but letting AnyEvent chose the model is generally better.
938 1122
939=head2 MAINLOOP EMULATION 1123=head2 MAINLOOP EMULATION
940 1124
941Sometimes (often for short test scripts, or even standalone programs who 1125Sometimes (often for short test scripts, or even standalone programs who
954 1138
955 1139
956=head1 OTHER MODULES 1140=head1 OTHER MODULES
957 1141
958The following is a non-exhaustive list of additional modules that use 1142The following is a non-exhaustive list of additional modules that use
959AnyEvent as a client and can therefore be mixed easily with other AnyEvent 1143AnyEvent as a client and can therefore be mixed easily with other
960modules and other event loops in the same program. Some of the modules 1144AnyEvent modules and other event loops in the same program. Some of the
961come with AnyEvent, most are available via CPAN. 1145modules come as part of AnyEvent, the others are available via CPAN (see
1146L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
1147a longer non-exhaustive list), and the list is heavily biased towards
1148modules of the AnyEvent author himself :)
962 1149
963=over 4 1150=over 4
964 1151
965=item L<AnyEvent::Util> 1152=item L<AnyEvent::Util>
966 1153
967Contains various utility functions that replace often-used but blocking 1154Contains various utility functions that replace often-used blocking
968functions such as C<inet_aton> by event-/callback-based versions. 1155functions such as C<inet_aton> with event/callback-based versions.
969 1156
970=item L<AnyEvent::Socket> 1157=item L<AnyEvent::Socket>
971 1158
972Provides various utility functions for (internet protocol) sockets, 1159Provides various utility functions for (internet protocol) sockets,
973addresses and name resolution. Also functions to create non-blocking tcp 1160addresses and name resolution. Also functions to create non-blocking tcp
975 1162
976=item L<AnyEvent::Handle> 1163=item L<AnyEvent::Handle>
977 1164
978Provide read and write buffers, manages watchers for reads and writes, 1165Provide read and write buffers, manages watchers for reads and writes,
979supports raw and formatted I/O, I/O queued and fully transparent and 1166supports raw and formatted I/O, I/O queued and fully transparent and
980non-blocking SSL/TLS (via L<AnyEvent::TLS>. 1167non-blocking SSL/TLS (via L<AnyEvent::TLS>).
981 1168
982=item L<AnyEvent::DNS> 1169=item L<AnyEvent::DNS>
983 1170
984Provides rich asynchronous DNS resolver capabilities. 1171Provides rich asynchronous DNS resolver capabilities.
985 1172
1173=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
1174
1175Implement event-based interfaces to the protocols of the same name (for
1176the curious, IGS is the International Go Server and FCP is the Freenet
1177Client Protocol).
1178
986=item L<AnyEvent::HTTP> 1179=item L<AnyEvent::AIO>
987 1180
988A simple-to-use HTTP library that is capable of making a lot of concurrent 1181Truly asynchronous (as opposed to non-blocking) I/O, should be in the
989HTTP requests. 1182toolbox of every event programmer. AnyEvent::AIO transparently fuses
1183L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
1184file I/O, and much more.
1185
1186=item L<AnyEvent::Filesys::Notify>
1187
1188AnyEvent is good for non-blocking stuff, but it can't detect file or
1189path changes (e.g. "watch this directory for new files", "watch this
1190file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
1191do just that in a portbale fashion, supporting inotify on GNU/Linux and
1192some weird, without doubt broken, stuff on OS X to monitor files. It can
1193fall back to blocking scans at regular intervals transparently on other
1194platforms, so it's about as portable as it gets.
1195
1196(I haven't used it myself, but I haven't heard anybody complaining about
1197it yet).
1198
1199=item L<AnyEvent::DBI>
1200
1201Executes L<DBI> requests asynchronously in a proxy process for you,
1202notifying you in an event-based way when the operation is finished.
990 1203
991=item L<AnyEvent::HTTPD> 1204=item L<AnyEvent::HTTPD>
992 1205
993Provides a simple web application server framework. 1206A simple embedded webserver.
994 1207
995=item L<AnyEvent::FastPing> 1208=item L<AnyEvent::FastPing>
996 1209
997The fastest ping in the west. 1210The fastest ping in the west.
998 1211
999=item L<AnyEvent::DBI>
1000
1001Executes L<DBI> requests asynchronously in a proxy process.
1002
1003=item L<AnyEvent::AIO>
1004
1005Truly asynchronous I/O, should be in the toolbox of every event
1006programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1007together.
1008
1009=item L<AnyEvent::BDB>
1010
1011Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1012L<BDB> and AnyEvent together.
1013
1014=item L<AnyEvent::GPSD>
1015
1016A non-blocking interface to gpsd, a daemon delivering GPS information.
1017
1018=item L<AnyEvent::IRC>
1019
1020AnyEvent based IRC client module family (replacing the older Net::IRC3).
1021
1022=item L<AnyEvent::XMPP>
1023
1024AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1025Net::XMPP2>.
1026
1027=item L<AnyEvent::IGS>
1028
1029A non-blocking interface to the Internet Go Server protocol (used by
1030L<App::IGS>).
1031
1032=item L<Net::FCP>
1033
1034AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1035of AnyEvent.
1036
1037=item L<Event::ExecFlow>
1038
1039High level API for event-based execution flow control.
1040
1041=item L<Coro> 1212=item L<Coro>
1042 1213
1043Has special support for AnyEvent via L<Coro::AnyEvent>. 1214Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
1215to simply invert the flow control - don't call us, we will call you:
1216
1217 async {
1218 Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
1219 print "5 seconds later!\n";
1220
1221 Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
1222 my $line = <STDIN>; # works for ttys
1223
1224 AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
1225 my ($body, $hdr) = Coro::rouse_wait;
1226 };
1044 1227
1045=back 1228=back
1046 1229
1047=cut 1230=cut
1048 1231
1049package AnyEvent; 1232package AnyEvent;
1050 1233
1051# basically a tuned-down version of common::sense 1234# basically a tuned-down version of common::sense
1052sub common_sense { 1235sub common_sense {
1053 # no warnings 1236 # from common:.sense 3.5
1054 ${^WARNING_BITS} ^= ${^WARNING_BITS}; 1237 local $^W;
1055 # use strict vars subs 1238 ${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1239 # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1056 $^H |= 0x00000600; 1240 $^H |= 0x00000600;
1057} 1241}
1058 1242
1059BEGIN { AnyEvent::common_sense } 1243BEGIN { AnyEvent::common_sense }
1060 1244
1061use Carp (); 1245use Carp ();
1062 1246
1063our $VERSION = 4.85; 1247our $VERSION = '7.04';
1064our $MODEL; 1248our $MODEL;
1065
1066our $AUTOLOAD;
1067our @ISA; 1249our @ISA;
1068
1069our @REGISTRY; 1250our @REGISTRY;
1070
1071our $WIN32;
1072
1073our $VERBOSE; 1251our $VERBOSE;
1252our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1253our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1074 1254
1075BEGIN { 1255BEGIN {
1076 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1256 require "AnyEvent/constants.pl";
1257
1077 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1258 eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1078 1259
1079 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1260 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1080 if ${^TAINT}; 1261 if ${^TAINT};
1081 1262
1082 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1263 $ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
1264 for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1083 1265
1084} 1266 @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
1267 if ${^TAINT};
1085 1268
1086our $MAX_SIGNAL_LATENCY = 10; 1269 # $ENV{PERL_ANYEVENT_xxx} now valid
1087 1270
1088our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1271 $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1089 1272
1090{
1091 my $idx; 1273 my $idx;
1092 $PROTOCOL{$_} = ++$idx 1274 $PROTOCOL{$_} = ++$idx
1093 for reverse split /\s*,\s*/, 1275 for reverse split /\s*,\s*/,
1094 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1276 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1095} 1277}
1096 1278
1279our @post_detect;
1280
1281sub post_detect(&) {
1282 my ($cb) = @_;
1283
1284 push @post_detect, $cb;
1285
1286 defined wantarray
1287 ? bless \$cb, "AnyEvent::Util::postdetect"
1288 : ()
1289}
1290
1291sub AnyEvent::Util::postdetect::DESTROY {
1292 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1293}
1294
1295our $POSTPONE_W;
1296our @POSTPONE;
1297
1298sub _postpone_exec {
1299 undef $POSTPONE_W;
1300
1301 &{ shift @POSTPONE }
1302 while @POSTPONE;
1303}
1304
1305sub postpone(&) {
1306 push @POSTPONE, shift;
1307
1308 $POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
1309
1310 ()
1311}
1312
1313sub log($$;@) {
1314 # only load the big bloated module when we actually are about to log something
1315 if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
1316 local ($!, $@);
1317 require AnyEvent::Log; # among other things, sets $VERBOSE to 9
1318 # AnyEvent::Log overwrites this function
1319 goto &log;
1320 }
1321
1322 0 # not logged
1323}
1324
1325sub _logger($;$) {
1326 my ($level, $renabled) = @_;
1327
1328 $$renabled = $level <= $VERBOSE;
1329
1330 my $logger = [(caller)[0], $level, $renabled];
1331
1332 $AnyEvent::Log::LOGGER{$logger+0} = $logger;
1333
1334# return unless defined wantarray;
1335#
1336# require AnyEvent::Util;
1337# my $guard = AnyEvent::Util::guard (sub {
1338# # "clean up"
1339# delete $LOGGER{$logger+0};
1340# });
1341#
1342# sub {
1343# return 0 unless $$renabled;
1344#
1345# $guard if 0; # keep guard alive, but don't cause runtime overhead
1346# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
1347# package AnyEvent::Log;
1348# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
1349# }
1350}
1351
1352if (length $ENV{PERL_ANYEVENT_LOG}) {
1353 require AnyEvent::Log; # AnyEvent::Log does the thing for us
1354}
1355
1097my @models = ( 1356our @models = (
1098 [EV:: => AnyEvent::Impl::EV::], 1357 [EV:: => AnyEvent::Impl::EV::],
1099 [Event:: => AnyEvent::Impl::Event::],
1100 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 1358 [AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1101 # everything below here will not be autoprobed 1359 # everything below here will not (normally) be autoprobed
1102 # as the pureperl backend should work everywhere 1360 # as the pure perl backend should work everywhere
1103 # and is usually faster 1361 # and is usually faster
1362 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
1363 [Event:: => AnyEvent::Impl::Event::], # slow, stable
1104 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers 1364 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1365 # everything below here should not be autoloaded
1105 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1366 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1106 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1367 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1107 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1368 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1108 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1369 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1109 [Wx:: => AnyEvent::Impl::POE::], 1370 [Wx:: => AnyEvent::Impl::POE::],
1110 [Prima:: => AnyEvent::Impl::POE::], 1371 [Prima:: => AnyEvent::Impl::POE::],
1111 # IO::Async is just too broken - we would need workarounds for its 1372 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1112 # byzantine signal and broken child handling, among others. 1373 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1113 # IO::Async is rather hard to detect, as it doesn't have any 1374 [FLTK:: => AnyEvent::Impl::FLTK::],
1114 # obvious default class.
1115# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1116# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1117# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1118); 1375);
1119 1376
1120our %method = map +($_ => 1), 1377our @isa_hook;
1378
1379sub _isa_set {
1380 my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
1381
1382 @{"$pkg[$_-1]::ISA"} = $pkg[$_]
1383 for 1 .. $#pkg;
1384
1385 grep $_ && $_->[1], @isa_hook
1386 and AE::_reset ();
1387}
1388
1389# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
1390sub _isa_hook($$;$) {
1391 my ($i, $pkg, $reset_ae) = @_;
1392
1393 $isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
1394
1395 _isa_set;
1396}
1397
1398# all autoloaded methods reserve the complete glob, not just the method slot.
1399# due to bugs in perls method cache implementation.
1121 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1400our @methods = qw(io timer time now now_update signal child idle condvar);
1122 1401
1123our @post_detect;
1124
1125sub post_detect(&) { 1402sub detect() {
1126 my ($cb) = @_; 1403 return $MODEL if $MODEL; # some programs keep references to detect
1127 1404
1128 if ($MODEL) { 1405 # IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1129 $cb->(); 1406 # the author knows about the problems and what it does to AnyEvent as a whole
1407 # (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
1408 # anyway.
1409 AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
1410 . "design, abuses internals and breaks AnyEvent - will not continue."
1411 if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1130 1412
1131 1 1413 local $!; # for good measure
1414 local $SIG{__DIE__}; # we use eval
1415
1416 # free some memory
1417 *detect = sub () { $MODEL };
1418 # undef &func doesn't correctly update the method cache. grmbl.
1419 # so we delete the whole glob. grmbl.
1420 # otoh, perl doesn't let me undef an active usb, but it lets me free
1421 # a glob with an active sub. hrm. i hope it works, but perl is
1422 # usually buggy in this department. sigh.
1423 delete @{"AnyEvent::"}{@methods};
1424 undef @methods;
1425
1426 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
1427 my $model = $1;
1428 $model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
1429 if (eval "require $model") {
1430 AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
1431 $MODEL = $model;
1132 } else { 1432 } else {
1133 push @post_detect, $cb; 1433 AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1134 1434 }
1135 defined wantarray
1136 ? bless \$cb, "AnyEvent::Util::postdetect"
1137 : ()
1138 } 1435 }
1139}
1140 1436
1141sub AnyEvent::Util::postdetect::DESTROY { 1437 # check for already loaded models
1142 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1143}
1144
1145sub detect() {
1146 unless ($MODEL) { 1438 unless ($MODEL) {
1147 local $SIG{__DIE__}; 1439 for (@REGISTRY, @models) {
1148 1440 my ($package, $model) = @$_;
1149 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1441 if (${"$package\::VERSION"} > 0) {
1150 my $model = "AnyEvent::Impl::$1";
1151 if (eval "require $model") { 1442 if (eval "require $model") {
1443 AnyEvent::log 7 => "Autodetected model '$model', using it.";
1152 $MODEL = $model; 1444 $MODEL = $model;
1153 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; 1445 last;
1154 } else { 1446 } else {
1155 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; 1447 AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
1448 }
1156 } 1449 }
1157 } 1450 }
1158 1451
1159 # check for already loaded models
1160 unless ($MODEL) { 1452 unless ($MODEL) {
1453 # try to autoload a model
1161 for (@REGISTRY, @models) { 1454 for (@REGISTRY, @models) {
1162 my ($package, $model) = @$_; 1455 my ($package, $model) = @$_;
1456 if (
1457 eval "require $package"
1163 if (${"$package\::VERSION"} > 0) { 1458 and ${"$package\::VERSION"} > 0
1164 if (eval "require $model") { 1459 and eval "require $model"
1460 ) {
1461 AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1165 $MODEL = $model; 1462 $MODEL = $model;
1166 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1167 last; 1463 last;
1168 }
1169 } 1464 }
1170 } 1465 }
1171 1466
1172 unless ($MODEL) {
1173 # try to load a model
1174
1175 for (@REGISTRY, @models) {
1176 my ($package, $model) = @$_;
1177 if (eval "require $package"
1178 and ${"$package\::VERSION"} > 0
1179 and eval "require $model") {
1180 $MODEL = $model;
1181 warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1182 last;
1183 }
1184 }
1185
1186 $MODEL 1467 $MODEL
1187 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; 1468 or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1188 }
1189 } 1469 }
1190
1191 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1192
1193 unshift @ISA, $MODEL;
1194
1195 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1196
1197 (shift @post_detect)->() while @post_detect;
1198 } 1470 }
1199 1471
1472 # free memory only needed for probing
1473 undef @models;
1474 undef @REGISTRY;
1475
1476 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1477
1478 # now nuke some methods that are overridden by the backend.
1479 # SUPER usage is not allowed in these.
1480 for (qw(time signal child idle)) {
1481 undef &{"AnyEvent::Base::$_"}
1482 if defined &{"$MODEL\::$_"};
1483 }
1484
1485 _isa_set;
1486
1487 # we're officially open!
1488
1489 if ($ENV{PERL_ANYEVENT_STRICT}) {
1490 require AnyEvent::Strict;
1491 }
1492
1493 if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
1494 require AnyEvent::Debug;
1495 AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
1496 }
1497
1498 if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
1499 require AnyEvent::Socket;
1500 require AnyEvent::Debug;
1501
1502 my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
1503 $shell =~ s/\$\$/$$/g;
1504
1505 my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
1506 $AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
1507 }
1508
1509 # now the anyevent environment is set up as the user told us to, so
1510 # call the actual user code - post detects
1511
1512 (shift @post_detect)->() while @post_detect;
1513 undef @post_detect;
1514
1515 *post_detect = sub(&) {
1516 shift->();
1517
1518 undef
1519 };
1520
1200 $MODEL 1521 $MODEL
1201} 1522}
1202 1523
1203sub AUTOLOAD { 1524for my $name (@methods) {
1204 (my $func = $AUTOLOAD) =~ s/.*://; 1525 *$name = sub {
1205 1526 detect;
1206 $method{$func} 1527 # we use goto because
1207 or Carp::croak "$func: not a valid method for AnyEvent objects"; 1528 # a) it makes the thunk more transparent
1208 1529 # b) it allows us to delete the thunk later
1209 detect unless $MODEL; 1530 goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1210 1531 };
1211 my $class = shift;
1212 $class->$func (@_);
1213} 1532}
1214 1533
1215# utility function to dup a filehandle. this is used by many backends 1534# utility function to dup a filehandle. this is used by many backends
1216# to support binding more than one watcher per filehandle (they usually 1535# to support binding more than one watcher per filehandle (they usually
1217# allow only one watcher per fd, so we dup it to get a different one). 1536# allow only one watcher per fd, so we dup it to get a different one).
1227 # we assume CLOEXEC is already set by perl in all important cases 1546 # we assume CLOEXEC is already set by perl in all important cases
1228 1547
1229 ($fh2, $rw) 1548 ($fh2, $rw)
1230} 1549}
1231 1550
1551=head1 SIMPLIFIED AE API
1552
1553Starting with version 5.0, AnyEvent officially supports a second, much
1554simpler, API that is designed to reduce the calling, typing and memory
1555overhead by using function call syntax and a fixed number of parameters.
1556
1557See the L<AE> manpage for details.
1558
1559=cut
1560
1561package AE;
1562
1563our $VERSION = $AnyEvent::VERSION;
1564
1565sub _reset() {
1566 eval q{
1567 # fall back to the main API by default - backends and AnyEvent::Base
1568 # implementations can overwrite these.
1569
1570 sub io($$$) {
1571 AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1572 }
1573
1574 sub timer($$$) {
1575 AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1576 }
1577
1578 sub signal($$) {
1579 AnyEvent->signal (signal => $_[0], cb => $_[1])
1580 }
1581
1582 sub child($$) {
1583 AnyEvent->child (pid => $_[0], cb => $_[1])
1584 }
1585
1586 sub idle($) {
1587 AnyEvent->idle (cb => $_[0]);
1588 }
1589
1590 sub cv(;&) {
1591 AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1592 }
1593
1594 sub now() {
1595 AnyEvent->now
1596 }
1597
1598 sub now_update() {
1599 AnyEvent->now_update
1600 }
1601
1602 sub time() {
1603 AnyEvent->time
1604 }
1605
1606 *postpone = \&AnyEvent::postpone;
1607 *log = \&AnyEvent::log;
1608 };
1609 die if $@;
1610}
1611
1612BEGIN { _reset }
1613
1232package AnyEvent::Base; 1614package AnyEvent::Base;
1233 1615
1234# default implementations for many methods 1616# default implementations for many methods
1235 1617
1236sub _time { 1618sub time {
1619 eval q{ # poor man's autoloading {}
1237 # probe for availability of Time::HiRes 1620 # probe for availability of Time::HiRes
1238 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1621 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1239 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1622 *time = sub { Time::HiRes::time () };
1240 *_time = \&Time::HiRes::time; 1623 *AE::time = \& Time::HiRes::time ;
1624 *now = \&time;
1625 AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1241 # if (eval "use POSIX (); (POSIX::times())... 1626 # if (eval "use POSIX (); (POSIX::times())...
1242 } else { 1627 } else {
1243 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; 1628 *time = sub { CORE::time };
1244 *_time = sub { time }; # epic fail 1629 *AE::time = sub (){ CORE::time };
1630 *now = \&time;
1631 AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
1632 }
1245 } 1633 };
1634 die if $@;
1246 1635
1247 &_time 1636 &time
1248} 1637}
1249 1638
1250sub time { _time } 1639*now = \&time;
1251sub now { _time }
1252sub now_update { } 1640sub now_update { }
1253 1641
1642sub _poll {
1643 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
1644}
1645
1254# default implementation for ->condvar 1646# default implementation for ->condvar
1647# in fact, the default should not be overwritten
1255 1648
1256sub condvar { 1649sub condvar {
1650 eval q{ # poor man's autoloading {}
1651 *condvar = sub {
1257 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" 1652 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1653 };
1654
1655 *AE::cv = sub (;&) {
1656 bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
1657 };
1658 };
1659 die if $@;
1660
1661 &condvar
1258} 1662}
1259 1663
1260# default implementation for ->signal 1664# default implementation for ->signal
1261 1665
1262our $HAVE_ASYNC_INTERRUPT; 1666our $HAVE_ASYNC_INTERRUPT;
1667
1668sub _have_async_interrupt() {
1669 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1670 && eval "use Async::Interrupt 1.02 (); 1")
1671 unless defined $HAVE_ASYNC_INTERRUPT;
1672
1673 $HAVE_ASYNC_INTERRUPT
1674}
1675
1263our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1676our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1264our (%SIG_ASY, %SIG_ASY_W); 1677our (%SIG_ASY, %SIG_ASY_W);
1265our ($SIG_COUNT, $SIG_TW); 1678our ($SIG_COUNT, $SIG_TW);
1266 1679
1267sub _signal_exec {
1268 $HAVE_ASYNC_INTERRUPT
1269 ? $SIGPIPE_R->drain
1270 : sysread $SIGPIPE_R, my $dummy, 9;
1271
1272 while (%SIG_EV) {
1273 for (keys %SIG_EV) {
1274 delete $SIG_EV{$_};
1275 $_->() for values %{ $SIG_CB{$_} || {} };
1276 }
1277 }
1278}
1279
1280# install a dumym wakeupw atcher to reduce signal catching latency 1680# install a dummy wakeup watcher to reduce signal catching latency
1681# used by Impls
1281sub _sig_add() { 1682sub _sig_add() {
1282 unless ($SIG_COUNT++) { 1683 unless ($SIG_COUNT++) {
1283 # try to align timer on a full-second boundary, if possible 1684 # try to align timer on a full-second boundary, if possible
1284 my $NOW = AnyEvent->now; 1685 my $NOW = AE::now;
1285 1686
1286 $SIG_TW = AnyEvent->timer ( 1687 $SIG_TW = AE::timer
1287 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW), 1688 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1288 interval => $MAX_SIGNAL_LATENCY, 1689 $MAX_SIGNAL_LATENCY,
1289 cb => sub { }, # just for the PERL_ASYNC_CHECK 1690 sub { } # just for the PERL_ASYNC_CHECK
1290 ); 1691 ;
1291 } 1692 }
1292} 1693}
1293 1694
1294sub _sig_del { 1695sub _sig_del {
1295 undef $SIG_TW 1696 undef $SIG_TW
1296 unless --$SIG_COUNT; 1697 unless --$SIG_COUNT;
1297} 1698}
1298 1699
1700our $_sig_name_init; $_sig_name_init = sub {
1701 eval q{ # poor man's autoloading {}
1702 undef $_sig_name_init;
1703
1704 if (_have_async_interrupt) {
1705 *sig2num = \&Async::Interrupt::sig2num;
1706 *sig2name = \&Async::Interrupt::sig2name;
1707 } else {
1708 require Config;
1709
1710 my %signame2num;
1711 @signame2num{ split ' ', $Config::Config{sig_name} }
1712 = split ' ', $Config::Config{sig_num};
1713
1714 my @signum2name;
1715 @signum2name[values %signame2num] = keys %signame2num;
1716
1717 *sig2num = sub($) {
1718 $_[0] > 0 ? shift : $signame2num{+shift}
1719 };
1720 *sig2name = sub ($) {
1721 $_[0] > 0 ? $signum2name[+shift] : shift
1722 };
1723 }
1724 };
1725 die if $@;
1726};
1727
1728sub sig2num ($) { &$_sig_name_init; &sig2num }
1729sub sig2name($) { &$_sig_name_init; &sig2name }
1730
1299sub _signal { 1731sub signal {
1300 my (undef, %arg) = @_; 1732 eval q{ # poor man's autoloading {}
1733 # probe for availability of Async::Interrupt
1734 if (_have_async_interrupt) {
1735 AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1301 1736
1302 my $signal = uc $arg{signal} 1737 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1303 or Carp::croak "required option 'signal' is missing"; 1738 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1304 1739
1305 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1740 } else {
1741 AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1306 1742
1307 if ($HAVE_ASYNC_INTERRUPT) { 1743 if (AnyEvent::WIN32) {
1308 # async::interrupt 1744 require AnyEvent::Util;
1309 1745
1310 $SIG_ASY{$signal} ||= do { 1746 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1311 my $asy = new Async::Interrupt 1747 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1312 cb => sub { undef $SIG_EV{$signal} }, 1748 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1313 signal => $signal, 1749 } else {
1314 pipe => [$SIGPIPE_R->filenos], 1750 pipe $SIGPIPE_R, $SIGPIPE_W;
1751 fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1752 fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1753
1754 # not strictly required, as $^F is normally 2, but let's make sure...
1755 fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1756 fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1315 ; 1757 }
1316 $asy->pipe_autodrain (0);
1317 1758
1318 $asy 1759 $SIGPIPE_R
1760 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1761
1762 $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1763 }
1764
1765 *signal = $HAVE_ASYNC_INTERRUPT
1766 ? sub {
1767 my (undef, %arg) = @_;
1768
1769 # async::interrupt
1770 my $signal = sig2num $arg{signal};
1771 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1772
1773 $SIG_ASY{$signal} ||= new Async::Interrupt
1774 cb => sub { undef $SIG_EV{$signal} },
1775 signal => $signal,
1776 pipe => [$SIGPIPE_R->filenos],
1777 pipe_autodrain => 0,
1778 ;
1779
1780 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1781 }
1782 : sub {
1783 my (undef, %arg) = @_;
1784
1785 # pure perl
1786 my $signal = sig2name $arg{signal};
1787 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1788
1789 $SIG{$signal} ||= sub {
1790 local $!;
1791 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1792 undef $SIG_EV{$signal};
1793 };
1794
1795 # can't do signal processing without introducing races in pure perl,
1796 # so limit the signal latency.
1797 _sig_add;
1798
1799 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1800 }
1801 ;
1802
1803 *AnyEvent::Base::signal::DESTROY = sub {
1804 my ($signal, $cb) = @{$_[0]};
1805
1806 _sig_del;
1807
1808 delete $SIG_CB{$signal}{$cb};
1809
1810 $HAVE_ASYNC_INTERRUPT
1811 ? delete $SIG_ASY{$signal}
1812 : # delete doesn't work with older perls - they then
1813 # print weird messages, or just unconditionally exit
1814 # instead of getting the default action.
1815 undef $SIG{$signal}
1816 unless keys %{ $SIG_CB{$signal} };
1319 }; 1817 };
1320 1818
1321 } else { 1819 *_signal_exec = sub {
1322 # pure perl 1820 $HAVE_ASYNC_INTERRUPT
1821 ? $SIGPIPE_R->drain
1822 : sysread $SIGPIPE_R, (my $dummy), 9;
1323 1823
1324 $SIG{$signal} ||= sub { 1824 while (%SIG_EV) {
1325 local $!; 1825 for (keys %SIG_EV) {
1326 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1826 delete $SIG_EV{$_};
1327 undef $SIG_EV{$signal}; 1827 &$_ for values %{ $SIG_CB{$_} || {} };
1828 }
1829 }
1328 }; 1830 };
1329
1330 # can't do signal processing without introducing races in pure perl,
1331 # so limit the signal latency.
1332 _sig_add;
1333 } 1831 };
1832 die if $@;
1334 1833
1335 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1336}
1337
1338sub signal {
1339 # probe for availability of Async::Interrupt
1340 if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1341 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1342
1343 $HAVE_ASYNC_INTERRUPT = 1;
1344 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1345 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1346
1347 } else {
1348 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1349
1350 require Fcntl;
1351
1352 if (AnyEvent::WIN32) {
1353 require AnyEvent::Util;
1354
1355 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1356 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1357 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1358 } else {
1359 pipe $SIGPIPE_R, $SIGPIPE_W;
1360 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1361 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1362
1363 # not strictly required, as $^F is normally 2, but let's make sure...
1364 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1365 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1366 }
1367
1368 $SIGPIPE_R
1369 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1370
1371 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1372 }
1373
1374 *signal = \&_signal;
1375 &signal 1834 &signal
1376}
1377
1378sub AnyEvent::Base::signal::DESTROY {
1379 my ($signal, $cb) = @{$_[0]};
1380
1381 _sig_del;
1382
1383 delete $SIG_CB{$signal}{$cb};
1384
1385 $HAVE_ASYNC_INTERRUPT
1386 ? delete $SIG_ASY{$signal}
1387 : # delete doesn't work with older perls - they then
1388 # print weird messages, or just unconditionally exit
1389 # instead of getting the default action.
1390 undef $SIG{$signal}
1391 unless keys %{ $SIG_CB{$signal} };
1392} 1835}
1393 1836
1394# default implementation for ->child 1837# default implementation for ->child
1395 1838
1396our %PID_CB; 1839our %PID_CB;
1397our $CHLD_W; 1840our $CHLD_W;
1398our $CHLD_DELAY_W; 1841our $CHLD_DELAY_W;
1399our $WNOHANG;
1400 1842
1401sub _sigchld { 1843# used by many Impl's
1402 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1844sub _emit_childstatus($$) {
1403 $_->($pid, $?) 1845 my (undef, $rpid, $rstatus) = @_;
1846
1847 $_->($rpid, $rstatus)
1404 for values %{ $PID_CB{$pid} || {} }, 1848 for values %{ $PID_CB{$rpid} || {} },
1405 values %{ $PID_CB{0} || {} }; 1849 values %{ $PID_CB{0} || {} };
1406 }
1407} 1850}
1408 1851
1409sub child { 1852sub child {
1853 eval q{ # poor man's autoloading {}
1854 *_sigchld = sub {
1855 my $pid;
1856
1857 AnyEvent->_emit_childstatus ($pid, $?)
1858 while ($pid = waitpid -1, WNOHANG) > 0;
1859 };
1860
1861 *child = sub {
1410 my (undef, %arg) = @_; 1862 my (undef, %arg) = @_;
1411 1863
1412 defined (my $pid = $arg{pid} + 0) 1864 my $pid = $arg{pid};
1413 or Carp::croak "required option 'pid' is missing"; 1865 my $cb = $arg{cb};
1414 1866
1415 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1867 $PID_CB{$pid}{$cb+0} = $cb;
1416 1868
1417 # WNOHANG is almost cetrainly 1 everywhere
1418 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1419 ? 1
1420 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1421
1422 unless ($CHLD_W) { 1869 unless ($CHLD_W) {
1423 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1870 $CHLD_W = AE::signal CHLD => \&_sigchld;
1424 # child could be a zombie already, so make at least one round 1871 # child could be a zombie already, so make at least one round
1425 &_sigchld; 1872 &_sigchld;
1426 } 1873 }
1427 1874
1428 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1875 bless [$pid, $cb+0], "AnyEvent::Base::child"
1429} 1876 };
1430 1877
1431sub AnyEvent::Base::child::DESTROY { 1878 *AnyEvent::Base::child::DESTROY = sub {
1432 my ($pid, $cb) = @{$_[0]}; 1879 my ($pid, $icb) = @{$_[0]};
1433 1880
1434 delete $PID_CB{$pid}{$cb}; 1881 delete $PID_CB{$pid}{$icb};
1435 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1882 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1436 1883
1437 undef $CHLD_W unless keys %PID_CB; 1884 undef $CHLD_W unless keys %PID_CB;
1885 };
1886 };
1887 die if $@;
1888
1889 &child
1438} 1890}
1439 1891
1440# idle emulation is done by simply using a timer, regardless 1892# idle emulation is done by simply using a timer, regardless
1441# of whether the process is idle or not, and not letting 1893# of whether the process is idle or not, and not letting
1442# the callback use more than 50% of the time. 1894# the callback use more than 50% of the time.
1443sub idle { 1895sub idle {
1896 eval q{ # poor man's autoloading {}
1897 *idle = sub {
1444 my (undef, %arg) = @_; 1898 my (undef, %arg) = @_;
1445 1899
1446 my ($cb, $w, $rcb) = $arg{cb}; 1900 my ($cb, $w, $rcb) = $arg{cb};
1447 1901
1448 $rcb = sub { 1902 $rcb = sub {
1449 if ($cb) { 1903 if ($cb) {
1450 $w = _time; 1904 $w = AE::time;
1451 &$cb; 1905 &$cb;
1452 $w = _time - $w; 1906 $w = AE::time - $w;
1453 1907
1454 # never use more then 50% of the time for the idle watcher, 1908 # never use more then 50% of the time for the idle watcher,
1455 # within some limits 1909 # within some limits
1456 $w = 0.0001 if $w < 0.0001; 1910 $w = 0.0001 if $w < 0.0001;
1457 $w = 5 if $w > 5; 1911 $w = 5 if $w > 5;
1458 1912
1459 $w = AnyEvent->timer (after => $w, cb => $rcb); 1913 $w = AE::timer $w, 0, $rcb;
1460 } else { 1914 } else {
1461 # clean up... 1915 # clean up...
1462 undef $w; 1916 undef $w;
1463 undef $rcb; 1917 undef $rcb;
1918 }
1919 };
1920
1921 $w = AE::timer 0.05, 0, $rcb;
1922
1923 bless \\$cb, "AnyEvent::Base::idle"
1464 } 1924 };
1925
1926 *AnyEvent::Base::idle::DESTROY = sub {
1927 undef $${$_[0]};
1928 };
1465 }; 1929 };
1930 die if $@;
1466 1931
1467 $w = AnyEvent->timer (after => 0.05, cb => $rcb); 1932 &idle
1468
1469 bless \\$cb, "AnyEvent::Base::idle"
1470}
1471
1472sub AnyEvent::Base::idle::DESTROY {
1473 undef $${$_[0]};
1474} 1933}
1475 1934
1476package AnyEvent::CondVar; 1935package AnyEvent::CondVar;
1477 1936
1478our @ISA = AnyEvent::CondVar::Base::; 1937our @ISA = AnyEvent::CondVar::Base::;
1938
1939# only to be used for subclassing
1940sub new {
1941 my $class = shift;
1942 bless AnyEvent->condvar (@_), $class
1943}
1479 1944
1480package AnyEvent::CondVar::Base; 1945package AnyEvent::CondVar::Base;
1481 1946
1482#use overload 1947#use overload
1483# '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1948# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1493 1958
1494sub _send { 1959sub _send {
1495 # nop 1960 # nop
1496} 1961}
1497 1962
1963sub _wait {
1964 AnyEvent->_poll until $_[0]{_ae_sent};
1965}
1966
1498sub send { 1967sub send {
1499 my $cv = shift; 1968 my $cv = shift;
1500 $cv->{_ae_sent} = [@_]; 1969 $cv->{_ae_sent} = [@_];
1501 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; 1970 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1502 $cv->_send; 1971 $cv->_send;
1509 1978
1510sub ready { 1979sub ready {
1511 $_[0]{_ae_sent} 1980 $_[0]{_ae_sent}
1512} 1981}
1513 1982
1514sub _wait {
1515 $WAITING
1516 and !$_[0]{_ae_sent}
1517 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1518
1519 local $WAITING = 1;
1520 AnyEvent->one_event while !$_[0]{_ae_sent};
1521}
1522
1523sub recv { 1983sub recv {
1984 unless ($_[0]{_ae_sent}) {
1985 $WAITING
1986 and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
1987
1988 local $WAITING = 1;
1524 $_[0]->_wait; 1989 $_[0]->_wait;
1990 }
1525 1991
1526 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1992 $_[0]{_ae_croak}
1527 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] 1993 and Carp::croak $_[0]{_ae_croak};
1994
1995 wantarray
1996 ? @{ $_[0]{_ae_sent} }
1997 : $_[0]{_ae_sent}[0]
1528} 1998}
1529 1999
1530sub cb { 2000sub cb {
1531 $_[0]{_ae_cb} = $_[1] if @_ > 1; 2001 my $cv = shift;
2002
2003 @_
2004 and $cv->{_ae_cb} = shift
2005 and $cv->{_ae_sent}
2006 and (delete $cv->{_ae_cb})->($cv);
2007
1532 $_[0]{_ae_cb} 2008 $cv->{_ae_cb}
1533} 2009}
1534 2010
1535sub begin { 2011sub begin {
1536 ++$_[0]{_ae_counter}; 2012 ++$_[0]{_ae_counter};
1537 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 2013 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1542 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; 2018 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1543} 2019}
1544 2020
1545# undocumented/compatibility with pre-3.4 2021# undocumented/compatibility with pre-3.4
1546*broadcast = \&send; 2022*broadcast = \&send;
1547*wait = \&_wait; 2023*wait = \&recv;
1548 2024
1549=head1 ERROR AND EXCEPTION HANDLING 2025=head1 ERROR AND EXCEPTION HANDLING
1550 2026
1551In general, AnyEvent does not do any error handling - it relies on the 2027In general, AnyEvent does not do any error handling - it relies on the
1552caller to do that if required. The L<AnyEvent::Strict> module (see also 2028caller to do that if required. The L<AnyEvent::Strict> module (see also
1564$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and 2040$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1565so on. 2041so on.
1566 2042
1567=head1 ENVIRONMENT VARIABLES 2043=head1 ENVIRONMENT VARIABLES
1568 2044
1569The following environment variables are used by this module or its 2045AnyEvent supports a number of environment variables that tune the
1570submodules. 2046runtime behaviour. They are usually evaluated when AnyEvent is
2047loaded, initialised, or a submodule that uses them is loaded. Many of
2048them also cause AnyEvent to load additional modules - for example,
2049C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
2050loaded.
1571 2051
1572Note that AnyEvent will remove I<all> environment variables starting with 2052All the environment variables documented here start with
1573C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is 2053C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1574enabled. 2054namespace. Other modules are encouraged (but by no means required) to use
2055C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
2056namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
2057be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
2058variables starting with C<AE_>, see below).
2059
2060All variables can also be set via the C<AE_> prefix, that is, instead
2061of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
2062case there is a clash btween anyevent and another program that uses
2063C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
2064variable to the empty string, as those variables take precedence.
2065
2066When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
2067to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
2068exists. If taint mode is on, then AnyEvent will remove I<all> environment
2069variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
2070with C<undef> or the empty string, if the corresaponding C<AE_> variable
2071is set).
2072
2073The exact algorithm is currently:
2074
2075 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
2076 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
2077 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
2078
2079This ensures that child processes will not see the C<AE_> variables.
2080
2081The following environment variables are currently known to AnyEvent:
1575 2082
1576=over 4 2083=over 4
1577 2084
1578=item C<PERL_ANYEVENT_VERBOSE> 2085=item C<PERL_ANYEVENT_VERBOSE>
1579 2086
1580By default, AnyEvent will be completely silent except in fatal 2087By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1581conditions. You can set this environment variable to make AnyEvent more 2088higher (see L<AnyEvent::Log>). You can set this environment variable to a
1582talkative. 2089numerical loglevel to make AnyEvent more (or less) talkative.
1583 2090
2091If you want to do more than just set the global logging level
2092you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
2093complex specifications.
2094
2095When set to C<0> (C<off>), then no messages whatsoever will be logged with
2096everything else at defaults.
2097
1584When set to C<1> or higher, causes AnyEvent to warn about unexpected 2098When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1585conditions, such as not being able to load the event model specified by 2099conditions, such as not being able to load the event model specified by
1586C<PERL_ANYEVENT_MODEL>. 2100C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
2101is the minimum recommended level for use during development.
1587 2102
1588When set to C<2> or higher, cause AnyEvent to report to STDERR which event 2103When set to C<7> or higher (info), AnyEvent reports which event model it
1589model it chooses. 2104chooses.
1590 2105
1591When set to C<8> or higher, then AnyEvent will report extra information on 2106When set to C<8> or higher (debug), then AnyEvent will report extra
1592which optional modules it loads and how it implements certain features. 2107information on which optional modules it loads and how it implements
2108certain features.
2109
2110=item C<PERL_ANYEVENT_LOG>
2111
2112Accepts rather complex logging specifications. For example, you could log
2113all C<debug> messages of some module to stderr, warnings and above to
2114stderr, and errors and above to syslog, with:
2115
2116 PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
2117
2118For the rather extensive details, see L<AnyEvent::Log>.
2119
2120This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
2121so will take effect even before AnyEvent has initialised itself.
2122
2123Note that specifying this environment variable causes the L<AnyEvent::Log>
2124module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
2125using the latter saves a few hundred kB of memory unless a module
2126explicitly needs the extra features of AnyEvent::Log.
1593 2127
1594=item C<PERL_ANYEVENT_STRICT> 2128=item C<PERL_ANYEVENT_STRICT>
1595 2129
1596AnyEvent does not do much argument checking by default, as thorough 2130AnyEvent does not do much argument checking by default, as thorough
1597argument checking is very costly. Setting this variable to a true value 2131argument checking is very costly. Setting this variable to a true value
1599check the arguments passed to most method calls. If it finds any problems, 2133check the arguments passed to most method calls. If it finds any problems,
1600it will croak. 2134it will croak.
1601 2135
1602In other words, enables "strict" mode. 2136In other words, enables "strict" mode.
1603 2137
1604Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense> 2138Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1605>>, it is definitely recommended to keep it off in production. Keeping 2139>>, it is definitely recommended to keep it off in production. Keeping
1606C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs 2140C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1607can be very useful, however. 2141can be very useful, however.
1608 2142
2143=item C<PERL_ANYEVENT_DEBUG_SHELL>
2144
2145If this env variable is nonempty, then its contents will be interpreted by
2146C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
2147replacing every occurance of C<$$> by the process pid). The shell object
2148is saved in C<$AnyEvent::Debug::SHELL>.
2149
2150This happens when the first watcher is created.
2151
2152For example, to bind a debug shell on a unix domain socket in
2153F<< /tmp/debug<pid>.sock >>, you could use this:
2154
2155 PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
2156 # connect with e.g.: socat readline /tmp/debug123.sock
2157
2158Or to bind to tcp port 4545 on localhost:
2159
2160 PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
2161 # connect with e.g.: telnet localhost 4545
2162
2163Note that creating sockets in F</tmp> or on localhost is very unsafe on
2164multiuser systems.
2165
2166=item C<PERL_ANYEVENT_DEBUG_WRAP>
2167
2168Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
2169debugging purposes. See C<AnyEvent::Debug::wrap> for details.
2170
1609=item C<PERL_ANYEVENT_MODEL> 2171=item C<PERL_ANYEVENT_MODEL>
1610 2172
1611This can be used to specify the event model to be used by AnyEvent, before 2173This can be used to specify the event model to be used by AnyEvent, before
1612auto detection and -probing kicks in. It must be a string consisting 2174auto detection and -probing kicks in.
1613entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 2175
2176It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
2177or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1614and the resulting module name is loaded and if the load was successful, 2178resulting module name is loaded and - if the load was successful - used as
1615used as event model. If it fails to load AnyEvent will proceed with 2179event model backend. If it fails to load then AnyEvent will proceed with
1616auto detection and -probing. 2180auto detection and -probing.
1617 2181
1618This functionality might change in future versions. 2182If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
2183nothing gets prepended and the module name is used as-is (hint: C<::> at
2184the end of a string designates a module name and quotes it appropriately).
1619 2185
1620For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 2186For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1621could start your program like this: 2187could start your program like this:
1622 2188
1623 PERL_ANYEVENT_MODEL=Perl perl ... 2189 PERL_ANYEVENT_MODEL=Perl perl ...
2190
2191=item C<PERL_ANYEVENT_IO_MODEL>
2192
2193The current file I/O model - see L<AnyEvent::IO> for more info.
2194
2195At the moment, only C<Perl> (small, pure-perl, synchronous) and
2196C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
2197L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1624 2198
1625=item C<PERL_ANYEVENT_PROTOCOLS> 2199=item C<PERL_ANYEVENT_PROTOCOLS>
1626 2200
1627Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences 2201Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1628for IPv4 or IPv6. The default is unspecified (and might change, or be the result 2202for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1641but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 2215but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1642- only support IPv4, never try to resolve or contact IPv6 2216- only support IPv4, never try to resolve or contact IPv6
1643addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 2217addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1644IPv6, but prefer IPv6 over IPv4. 2218IPv6, but prefer IPv6 over IPv4.
1645 2219
2220=item C<PERL_ANYEVENT_HOSTS>
2221
2222This variable, if specified, overrides the F</etc/hosts> file used by
2223L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
2224from that file instead.
2225
1646=item C<PERL_ANYEVENT_EDNS0> 2226=item C<PERL_ANYEVENT_EDNS0>
1647 2227
1648Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension 2228Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1649for DNS. This extension is generally useful to reduce DNS traffic, but 2229DNS. This extension is generally useful to reduce DNS traffic, especially
1650some (broken) firewalls drop such DNS packets, which is why it is off by 2230when DNSSEC is involved, but some (broken) firewalls drop such DNS
1651default. 2231packets, which is why it is off by default.
1652 2232
1653Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce 2233Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1654EDNS0 in its DNS requests. 2234EDNS0 in its DNS requests.
1655 2235
1656=item C<PERL_ANYEVENT_MAX_FORKS> 2236=item C<PERL_ANYEVENT_MAX_FORKS>
1662 2242
1663The default value for the C<max_outstanding> parameter for the default DNS 2243The default value for the C<max_outstanding> parameter for the default DNS
1664resolver - this is the maximum number of parallel DNS requests that are 2244resolver - this is the maximum number of parallel DNS requests that are
1665sent to the DNS server. 2245sent to the DNS server.
1666 2246
2247=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
2248
2249Perl has inherently racy signal handling (you can basically choose between
2250losing signals and memory corruption) - pure perl event loops (including
2251C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
2252have to poll regularly to avoid losing signals.
2253
2254Some event loops are racy, but don't poll regularly, and some event loops
2255are written in C but are still racy. For those event loops, AnyEvent
2256installs a timer that regularly wakes up the event loop.
2257
2258By default, the interval for this timer is C<10> seconds, but you can
2259override this delay with this environment variable (or by setting
2260the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
2261watchers).
2262
2263Lower values increase CPU (and energy) usage, higher values can introduce
2264long delays when reaping children or waiting for signals.
2265
2266The L<AnyEvent::Async> module, if available, will be used to avoid this
2267polling (with most event loops).
2268
1667=item C<PERL_ANYEVENT_RESOLV_CONF> 2269=item C<PERL_ANYEVENT_RESOLV_CONF>
1668 2270
1669The file to use instead of F</etc/resolv.conf> (or OS-specific 2271The absolute path to a F<resolv.conf>-style file to use instead of
1670configuration) in the default resolver. When set to the empty string, no 2272F</etc/resolv.conf> (or the OS-specific configuration) in the default
1671default config will be used. 2273resolver, or the empty string to select the default configuration.
1672 2274
1673=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. 2275=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1674 2276
1675When neither C<ca_file> nor C<ca_path> was specified during 2277When neither C<ca_file> nor C<ca_path> was specified during
1676L<AnyEvent::TLS> context creation, and either of these environment 2278L<AnyEvent::TLS> context creation, and either of these environment
1677variables exist, they will be used to specify CA certificate locations 2279variables are nonempty, they will be used to specify CA certificate
1678instead of a system-dependent default. 2280locations instead of a system-dependent default.
1679 2281
1680=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT> 2282=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1681 2283
1682When these are set to C<1>, then the respective modules are not 2284When these are set to C<1>, then the respective modules are not
1683loaded. Mostly good for testing AnyEvent itself. 2285loaded. Mostly good for testing AnyEvent itself.
1746 warn "read: $input\n"; # output what has been read 2348 warn "read: $input\n"; # output what has been read
1747 $cv->send if $input =~ /^q/i; # quit program if /^q/i 2349 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1748 }, 2350 },
1749 ); 2351 );
1750 2352
1751 my $time_watcher; # can only be used once
1752
1753 sub new_timer {
1754 $timer = AnyEvent->timer (after => 1, cb => sub { 2353 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1755 warn "timeout\n"; # print 'timeout' about every second 2354 warn "timeout\n"; # print 'timeout' at most every second
1756 &new_timer; # and restart the time
1757 }); 2355 });
1758 }
1759
1760 new_timer; # create first timer
1761 2356
1762 $cv->recv; # wait until user enters /^q/i 2357 $cv->recv; # wait until user enters /^q/i
1763 2358
1764=head1 REAL-WORLD EXAMPLE 2359=head1 REAL-WORLD EXAMPLE
1765 2360
1838 2433
1839The actual code goes further and collects all errors (C<die>s, exceptions) 2434The actual code goes further and collects all errors (C<die>s, exceptions)
1840that occurred during request processing. The C<result> method detects 2435that occurred during request processing. The C<result> method detects
1841whether an exception as thrown (it is stored inside the $txn object) 2436whether an exception as thrown (it is stored inside the $txn object)
1842and just throws the exception, which means connection errors and other 2437and just throws the exception, which means connection errors and other
1843problems get reported tot he code that tries to use the result, not in a 2438problems get reported to the code that tries to use the result, not in a
1844random callback. 2439random callback.
1845 2440
1846All of this enables the following usage styles: 2441All of this enables the following usage styles:
1847 2442
18481. Blocking: 24431. Blocking:
1896through AnyEvent. The benchmark creates a lot of timers (with a zero 2491through AnyEvent. The benchmark creates a lot of timers (with a zero
1897timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2492timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1898which it is), lets them fire exactly once and destroys them again. 2493which it is), lets them fire exactly once and destroys them again.
1899 2494
1900Source code for this benchmark is found as F<eg/bench> in the AnyEvent 2495Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1901distribution. 2496distribution. It uses the L<AE> interface, which makes a real difference
2497for the EV and Perl backends only.
1902 2498
1903=head3 Explanation of the columns 2499=head3 Explanation of the columns
1904 2500
1905I<watcher> is the number of event watchers created/destroyed. Since 2501I<watcher> is the number of event watchers created/destroyed. Since
1906different event models feature vastly different performances, each event 2502different event models feature vastly different performances, each event
1927watcher. 2523watcher.
1928 2524
1929=head3 Results 2525=head3 Results
1930 2526
1931 name watchers bytes create invoke destroy comment 2527 name watchers bytes create invoke destroy comment
1932 EV/EV 400000 224 0.47 0.35 0.27 EV native interface 2528 EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1933 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 2529 EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1934 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 2530 Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1935 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 2531 Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1936 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 2532 Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1937 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 2533 Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1938 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll 2534 IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1939 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll 2535 IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1940 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 2536 Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1941 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 2537 Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1942 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 2538 POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1943 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 2539 POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1944 2540
1945=head3 Discussion 2541=head3 Discussion
1946 2542
1947The benchmark does I<not> measure scalability of the event loop very 2543The benchmark does I<not> measure scalability of the event loop very
1948well. For example, a select-based event loop (such as the pure perl one) 2544well. For example, a select-based event loop (such as the pure perl one)
1960benchmark machine, handling an event takes roughly 1600 CPU cycles with 2556benchmark machine, handling an event takes roughly 1600 CPU cycles with
1961EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU 2557EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1962cycles with POE. 2558cycles with POE.
1963 2559
1964C<EV> is the sole leader regarding speed and memory use, which are both 2560C<EV> is the sole leader regarding speed and memory use, which are both
1965maximal/minimal, respectively. Even when going through AnyEvent, it uses 2561maximal/minimal, respectively. When using the L<AE> API there is zero
2562overhead (when going through the AnyEvent API create is about 5-6 times
2563slower, with other times being equal, so still uses far less memory than
1966far less memory than any other event loop and is still faster than Event 2564any other event loop and is still faster than Event natively).
1967natively.
1968 2565
1969The pure perl implementation is hit in a few sweet spots (both the 2566The pure perl implementation is hit in a few sweet spots (both the
1970constant timeout and the use of a single fd hit optimisations in the perl 2567constant timeout and the use of a single fd hit optimisations in the perl
1971interpreter and the backend itself). Nevertheless this shows that it 2568interpreter and the backend itself). Nevertheless this shows that it
1972adds very little overhead in itself. Like any select-based backend its 2569adds very little overhead in itself. Like any select-based backend its
2020(even when used without AnyEvent), but most event loops have acceptable 2617(even when used without AnyEvent), but most event loops have acceptable
2021performance with or without AnyEvent. 2618performance with or without AnyEvent.
2022 2619
2023=item * The overhead AnyEvent adds is usually much smaller than the overhead of 2620=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2024the actual event loop, only with extremely fast event loops such as EV 2621the actual event loop, only with extremely fast event loops such as EV
2025adds AnyEvent significant overhead. 2622does AnyEvent add significant overhead.
2026 2623
2027=item * You should avoid POE like the plague if you want performance or 2624=item * You should avoid POE like the plague if you want performance or
2028reasonable memory usage. 2625reasonable memory usage.
2029 2626
2030=back 2627=back
2046In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 2643In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2047(1%) are active. This mirrors the activity of large servers with many 2644(1%) are active. This mirrors the activity of large servers with many
2048connections, most of which are idle at any one point in time. 2645connections, most of which are idle at any one point in time.
2049 2646
2050Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 2647Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2051distribution. 2648distribution. It uses the L<AE> interface, which makes a real difference
2649for the EV and Perl backends only.
2052 2650
2053=head3 Explanation of the columns 2651=head3 Explanation of the columns
2054 2652
2055I<sockets> is the number of sockets, and twice the number of "servers" (as 2653I<sockets> is the number of sockets, and twice the number of "servers" (as
2056each server has a read and write socket end). 2654each server has a read and write socket end).
2064a new one that moves the timeout into the future. 2662a new one that moves the timeout into the future.
2065 2663
2066=head3 Results 2664=head3 Results
2067 2665
2068 name sockets create request 2666 name sockets create request
2069 EV 20000 69.01 11.16 2667 EV 20000 62.66 7.99
2070 Perl 20000 73.32 35.87 2668 Perl 20000 68.32 32.64
2071 IOAsync 20000 157.00 98.14 epoll 2669 IOAsync 20000 174.06 101.15 epoll
2072 IOAsync 20000 159.31 616.06 poll 2670 IOAsync 20000 174.67 610.84 poll
2073 Event 20000 212.62 257.32 2671 Event 20000 202.69 242.91
2074 Glib 20000 651.16 1896.30 2672 Glib 20000 557.01 1689.52
2075 POE 20000 349.67 12317.24 uses POE::Loop::Event 2673 POE 20000 341.54 12086.32 uses POE::Loop::Event
2076 2674
2077=head3 Discussion 2675=head3 Discussion
2078 2676
2079This benchmark I<does> measure scalability and overall performance of the 2677This benchmark I<does> measure scalability and overall performance of the
2080particular event loop. 2678particular event loop.
2206As you can see, the AnyEvent + EV combination even beats the 2804As you can see, the AnyEvent + EV combination even beats the
2207hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl 2805hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2208backend easily beats IO::Lambda and POE. 2806backend easily beats IO::Lambda and POE.
2209 2807
2210And even the 100% non-blocking version written using the high-level (and 2808And even the 100% non-blocking version written using the high-level (and
2211slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a 2809slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2212large margin, even though it does all of DNS, tcp-connect and socket I/O 2810higher level ("unoptimised") abstractions by a large margin, even though
2213in a non-blocking way. 2811it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2214 2812
2215The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and 2813The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2216F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are 2814F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2217part of the IO::lambda distribution and were used without any changes. 2815part of the IO::Lambda distribution and were used without any changes.
2218 2816
2219 2817
2220=head1 SIGNALS 2818=head1 SIGNALS
2221 2819
2222AnyEvent currently installs handlers for these signals: 2820AnyEvent currently installs handlers for these signals:
2259 unless defined $SIG{PIPE}; 2857 unless defined $SIG{PIPE};
2260 2858
2261=head1 RECOMMENDED/OPTIONAL MODULES 2859=head1 RECOMMENDED/OPTIONAL MODULES
2262 2860
2263One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and 2861One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2264it's built-in modules) are required to use it. 2862its built-in modules) are required to use it.
2265 2863
2266That does not mean that AnyEvent won't take advantage of some additional 2864That does not mean that AnyEvent won't take advantage of some additional
2267modules if they are installed. 2865modules if they are installed.
2268 2866
2269This section epxlains which additional modules will be used, and how they 2867This section explains which additional modules will be used, and how they
2270affect AnyEvent's operetion. 2868affect AnyEvent's operation.
2271 2869
2272=over 4 2870=over 4
2273 2871
2274=item L<Async::Interrupt> 2872=item L<Async::Interrupt>
2275 2873
2280catch the signals) with some delay (default is 10 seconds, look for 2878catch the signals) with some delay (default is 10 seconds, look for
2281C<$AnyEvent::MAX_SIGNAL_LATENCY>). 2879C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2282 2880
2283If this module is available, then it will be used to implement signal 2881If this module is available, then it will be used to implement signal
2284catching, which means that signals will not be delayed, and the event loop 2882catching, which means that signals will not be delayed, and the event loop
2285will not be interrupted regularly, which is more efficient (And good for 2883will not be interrupted regularly, which is more efficient (and good for
2286battery life on laptops). 2884battery life on laptops).
2287 2885
2288This affects not just the pure-perl event loop, but also other event loops 2886This affects not just the pure-perl event loop, but also other event loops
2289that have no signal handling on their own (e.g. Glib, Tk, Qt). 2887that have no signal handling on their own (e.g. Glib, Tk, Qt).
2290 2888
2302automatic timer adjustments even when no monotonic clock is available, 2900automatic timer adjustments even when no monotonic clock is available,
2303can take avdantage of advanced kernel interfaces such as C<epoll> and 2901can take avdantage of advanced kernel interfaces such as C<epoll> and
2304C<kqueue>, and is the fastest backend I<by far>. You can even embed 2902C<kqueue>, and is the fastest backend I<by far>. You can even embed
2305L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>). 2903L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2306 2904
2905If you only use backends that rely on another event loop (e.g. C<Tk>),
2906then this module will do nothing for you.
2907
2307=item L<Guard> 2908=item L<Guard>
2308 2909
2309The guard module, when used, will be used to implement 2910The guard module, when used, will be used to implement
2310C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a 2911C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2311lot less memory), but otherwise doesn't affect guard operation much. It is 2912lot less memory), but otherwise doesn't affect guard operation much. It is
2312purely used for performance. 2913purely used for performance.
2313 2914
2314=item L<JSON> and L<JSON::XS> 2915=item L<JSON> and L<JSON::XS>
2315 2916
2316This module is required when you want to read or write JSON data via 2917One of these modules is required when you want to read or write JSON data
2317L<AnyEvent::Handle>. It is also written in pure-perl, but can take 2918via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2318advantage of the ultra-high-speed L<JSON::XS> module when it is installed. 2919advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2319
2320In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2321installed.
2322 2920
2323=item L<Net::SSLeay> 2921=item L<Net::SSLeay>
2324 2922
2325Implementing TLS/SSL in Perl is certainly interesting, but not very 2923Implementing TLS/SSL in Perl is certainly interesting, but not very
2326worthwhile: If this module is installed, then L<AnyEvent::Handle> (with 2924worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2327the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL. 2925the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2328 2926
2329=item L<Time::HiRes> 2927=item L<Time::HiRes>
2330 2928
2331This module is part of perl since release 5.008. It will be used when the 2929This module is part of perl since release 5.008. It will be used when the
2332chosen event library does not come with a timing source on it's own. The 2930chosen event library does not come with a timing source of its own. The
2333pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to 2931pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2334try to use a monotonic clock for timing stability. 2932try to use a monotonic clock for timing stability.
2335 2933
2934=item L<AnyEvent::AIO> (and L<IO::AIO>)
2935
2936The default implementation of L<AnyEvent::IO> is to do I/O synchronously,
2937stopping programs while they access the disk, which is fine for a lot of
2938programs.
2939
2940Installing AnyEvent::AIO (and its IO::AIO dependency) makes it switch to
2941a true asynchronous implementation, so event processing can continue even
2942while waiting for disk I/O.
2943
2336=back 2944=back
2337 2945
2338 2946
2339=head1 FORK 2947=head1 FORK
2340 2948
2341Most event libraries are not fork-safe. The ones who are usually are 2949Most event libraries are not fork-safe. The ones who are usually are
2342because they rely on inefficient but fork-safe C<select> or C<poll> 2950because they rely on inefficient but fork-safe C<select> or C<poll> calls
2343calls. Only L<EV> is fully fork-aware. 2951- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2952are usually badly thought-out hacks that are incompatible with fork in
2953one way or another. Only L<EV> is fully fork-aware and ensures that you
2954continue event-processing in both parent and child (or both, if you know
2955what you are doing).
2956
2957This means that, in general, you cannot fork and do event processing in
2958the child if the event library was initialised before the fork (which
2959usually happens when the first AnyEvent watcher is created, or the library
2960is loaded).
2344 2961
2345If you have to fork, you must either do so I<before> creating your first 2962If you have to fork, you must either do so I<before> creating your first
2346watcher OR you must not use AnyEvent at all in the child OR you must do 2963watcher OR you must not use AnyEvent at all in the child OR you must do
2347something completely out of the scope of AnyEvent. 2964something completely out of the scope of AnyEvent.
2965
2966The problem of doing event processing in the parent I<and> the child
2967is much more complicated: even for backends that I<are> fork-aware or
2968fork-safe, their behaviour is not usually what you want: fork clones all
2969watchers, that means all timers, I/O watchers etc. are active in both
2970parent and child, which is almost never what you want. USing C<exec>
2971to start worker children from some kind of manage rprocess is usually
2972preferred, because it is much easier and cleaner, at the expense of having
2973to have another binary.
2348 2974
2349 2975
2350=head1 SECURITY CONSIDERATIONS 2976=head1 SECURITY CONSIDERATIONS
2351 2977
2352AnyEvent can be forced to load any event model via 2978AnyEvent can be forced to load any event model via
2382pronounced). 3008pronounced).
2383 3009
2384 3010
2385=head1 SEE ALSO 3011=head1 SEE ALSO
2386 3012
2387Utility functions: L<AnyEvent::Util>. 3013Tutorial/Introduction: L<AnyEvent::Intro>.
2388 3014
2389Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 3015FAQ: L<AnyEvent::FAQ>.
2390L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 3016
3017Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
3018(simply logging).
3019
3020Development/Debugging: L<AnyEvent::Strict> (stricter checking),
3021L<AnyEvent::Debug> (interactive shell, watcher tracing).
3022
3023Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
3024L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
3025L<Qt>, L<POE>, L<FLTK>.
2391 3026
2392Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 3027Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2393L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 3028L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2394L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 3029L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2395L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>. 3030L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
3031L<AnyEvent::Impl::FLTK>.
2396 3032
2397Non-blocking file handles, sockets, TCP clients and 3033Non-blocking handles, pipes, stream sockets, TCP clients and
2398servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 3034servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2399 3035
3036Asynchronous File I/O: L<AnyEvent::IO>.
3037
2400Asynchronous DNS: L<AnyEvent::DNS>. 3038Asynchronous DNS: L<AnyEvent::DNS>.
2401 3039
2402Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, 3040Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2403L<Coro::Event>,
2404 3041
2405Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>, 3042Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2406L<AnyEvent::HTTP>. 3043L<AnyEvent::HTTP>.
2407 3044
2408 3045
2409=head1 AUTHOR 3046=head1 AUTHOR
2410 3047
2411 Marc Lehmann <schmorp@schmorp.de> 3048 Marc Lehmann <schmorp@schmorp.de>
2412 http://home.schmorp.de/ 3049 http://anyevent.schmorp.de
2413 3050
2414=cut 3051=cut
2415 3052
24161 30531
2417 3054

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