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1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - the DBI of event loop programming 3AnyEvent - the DBI of event loop programming
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt 5EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6and POE are various supported event loops/environments. 6FLTK and POE are various supported event loops/environments.
7 7
8=head1 SYNOPSIS 8=head1 SYNOPSIS
9 9
10 use AnyEvent; 10 use AnyEvent;
11 11
12 # if you prefer function calls, look at the AE manpage for
13 # an alternative API.
14
12 # file descriptor readable 15 # file handle or descriptor readable
13 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); 16 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14 17
15 # one-shot or repeating timers 18 # one-shot or repeating timers
16 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); 19 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... 20 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18 21
19 print AnyEvent->now; # prints current event loop time 22 print AnyEvent->now; # prints current event loop time
20 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. 23 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21 24
22 # POSIX signal 25 # POSIX signal
43in a tutorial or some gentle introduction, have a look at the 46in a tutorial or some gentle introduction, have a look at the
44L<AnyEvent::Intro> manpage. 47L<AnyEvent::Intro> manpage.
45 48
46=head1 SUPPORT 49=head1 SUPPORT
47 50
51An FAQ document is available as L<AnyEvent::FAQ>.
52
48There is a mailinglist for discussing all things AnyEvent, and an IRC 53There also is a mailinglist for discussing all things AnyEvent, and an IRC
49channel, too. 54channel, too.
50 55
51See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software 56See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52Repository>, at L<http://anyevent.schmorp.de>, for more info. 57Repository>, at L<http://anyevent.schmorp.de>, for more info.
53 58
73module users into the same thing by forcing them to use the same event 78module users into the same thing by forcing them to use the same event
74model you use. 79model you use.
75 80
76For modules like POE or IO::Async (which is a total misnomer as it is 81For modules like POE or IO::Async (which is a total misnomer as it is
77actually doing all I/O I<synchronously>...), using them in your module is 82actually doing all I/O I<synchronously>...), using them in your module is
78like joining a cult: After you joined, you are dependent on them and you 83like joining a cult: After you join, you are dependent on them and you
79cannot use anything else, as they are simply incompatible to everything 84cannot use anything else, as they are simply incompatible to everything
80that isn't them. What's worse, all the potential users of your 85that isn't them. What's worse, all the potential users of your
81module are I<also> forced to use the same event loop you use. 86module are I<also> forced to use the same event loop you use.
82 87
83AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 88AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84fine. AnyEvent + Tk works fine etc. etc. but none of these work together 89fine. AnyEvent + Tk works fine etc. etc. but none of these work together
85with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if 90with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
86your module uses one of those, every user of your module has to use it, 91uses one of those, every user of your module has to use it, too. But if
87too. But if your module uses AnyEvent, it works transparently with all 92your module uses AnyEvent, it works transparently with all event models it
88event models it supports (including stuff like IO::Async, as long as those 93supports (including stuff like IO::Async, as long as those use one of the
89use one of the supported event loops. It is trivial to add new event loops 94supported event loops. It is easy to add new event loops to AnyEvent, too,
90to AnyEvent, too, so it is future-proof). 95so it is future-proof).
91 96
92In addition to being free of having to use I<the one and only true event 97In addition to being free of having to use I<the one and only true event
93model>, AnyEvent also is free of bloat and policy: with POE or similar 98model>, AnyEvent also is free of bloat and policy: with POE or similar
94modules, you get an enormous amount of code and strict rules you have to 99modules, you get an enormous amount of code and strict rules you have to
95follow. AnyEvent, on the other hand, is lean and up to the point, by only 100follow. AnyEvent, on the other hand, is lean and to the point, by only
96offering the functionality that is necessary, in as thin as a wrapper as 101offering the functionality that is necessary, in as thin as a wrapper as
97technically possible. 102technically possible.
98 103
99Of course, AnyEvent comes with a big (and fully optional!) toolbox 104Of course, AnyEvent comes with a big (and fully optional!) toolbox
100of useful functionality, such as an asynchronous DNS resolver, 100% 105of useful functionality, such as an asynchronous DNS resolver, 100%
106useful) and you want to force your users to use the one and only event 111useful) and you want to force your users to use the one and only event
107model, you should I<not> use this module. 112model, you should I<not> use this module.
108 113
109=head1 DESCRIPTION 114=head1 DESCRIPTION
110 115
111L<AnyEvent> provides an identical interface to multiple event loops. This 116L<AnyEvent> provides a uniform interface to various event loops. This
112allows module authors to utilise an event loop without forcing module 117allows module authors to use event loop functionality without forcing
113users to use the same event loop (as only a single event loop can coexist 118module users to use a specific event loop implementation (since more
114peacefully at any one time). 119than one event loop cannot coexist peacefully).
115 120
116The interface itself is vaguely similar, but not identical to the L<Event> 121The interface itself is vaguely similar, but not identical to the L<Event>
117module. 122module.
118 123
119During the first call of any watcher-creation method, the module tries 124During the first call of any watcher-creation method, the module tries
120to detect the currently loaded event loop by probing whether one of the 125to detect the currently loaded event loop by probing whether one of the
121following modules is already loaded: L<EV>, 126following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
122L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, 127L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
123L<POE>. The first one found is used. If none are found, the module tries 128found is used. If none are detected, the module tries to load the first
124to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl 129four modules in the order given; but note that if L<EV> is not
125adaptor should always succeed) in the order given. The first one that can 130available, the pure-perl L<AnyEvent::Loop> should always work, so
126be successfully loaded will be used. If, after this, still none could be 131the other two are not normally tried.
127found, AnyEvent will fall back to a pure-perl event loop, which is not
128very efficient, but should work everywhere.
129 132
130Because AnyEvent first checks for modules that are already loaded, loading 133Because AnyEvent first checks for modules that are already loaded, loading
131an event model explicitly before first using AnyEvent will likely make 134an event model explicitly before first using AnyEvent will likely make
132that model the default. For example: 135that model the default. For example:
133 136
135 use AnyEvent; 138 use AnyEvent;
136 139
137 # .. AnyEvent will likely default to Tk 140 # .. AnyEvent will likely default to Tk
138 141
139The I<likely> means that, if any module loads another event model and 142The I<likely> means that, if any module loads another event model and
140starts using it, all bets are off. Maybe you should tell their authors to 143starts using it, all bets are off - this case should be very rare though,
141use AnyEvent so their modules work together with others seamlessly... 144as very few modules hardcode event loops without announcing this very
145loudly.
142 146
143The pure-perl implementation of AnyEvent is called 147The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
144C<AnyEvent::Impl::Perl>. Like other event modules you can load it 148other event modules you can load it explicitly and enjoy the high
145explicitly and enjoy the high availability of that event loop :) 149availability of that event loop :)
146 150
147=head1 WATCHERS 151=head1 WATCHERS
148 152
149AnyEvent has the central concept of a I<watcher>, which is an object that 153AnyEvent has the central concept of a I<watcher>, which is an object that
150stores relevant data for each kind of event you are waiting for, such as 154stores relevant data for each kind of event you are waiting for, such as
155callback when the event occurs (of course, only when the event model 159callback when the event occurs (of course, only when the event model
156is in control). 160is in control).
157 161
158Note that B<callbacks must not permanently change global variables> 162Note that B<callbacks must not permanently change global variables>
159potentially in use by the event loop (such as C<$_> or C<$[>) and that B<< 163potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
160callbacks must not C<die> >>. The former is good programming practise in 164callbacks must not C<die> >>. The former is good programming practice in
161Perl and the latter stems from the fact that exception handling differs 165Perl and the latter stems from the fact that exception handling differs
162widely between event loops. 166widely between event loops.
163 167
164To disable the watcher you have to destroy it (e.g. by setting the 168To disable a watcher you have to destroy it (e.g. by setting the
165variable you store it in to C<undef> or otherwise deleting all references 169variable you store it in to C<undef> or otherwise deleting all references
166to it). 170to it).
167 171
168All watchers are created by calling a method on the C<AnyEvent> class. 172All watchers are created by calling a method on the C<AnyEvent> class.
169 173
170Many watchers either are used with "recursion" (repeating timers for 174Many watchers either are used with "recursion" (repeating timers for
171example), or need to refer to their watcher object in other ways. 175example), or need to refer to their watcher object in other ways.
172 176
173An any way to achieve that is this pattern: 177One way to achieve that is this pattern:
174 178
175 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 179 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176 # you can use $w here, for example to undef it 180 # you can use $w here, for example to undef it
177 undef $w; 181 undef $w;
178 }); 182 });
180Note 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,
181my variables are only visible after the statement in which they are 185my variables are only visible after the statement in which they are
182declared. 186declared.
183 187
184=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 );
185 195
186You 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
187with the following mandatory key-value pairs as arguments: 197with the following mandatory key-value pairs as arguments:
188 198
189C<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
204 214
205The 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.
206You 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
207underlying file descriptor. 217underlying file descriptor.
208 218
209Some event loops issue spurious readyness notifications, so you should 219Some event loops issue spurious readiness notifications, so you should
210always use non-blocking calls when reading/writing from/to your file 220always use non-blocking calls when reading/writing from/to your file
211handles. 221handles.
212 222
213Example: 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
214watcher. 224watcher.
219 undef $w; 229 undef $w;
220 }); 230 });
221 231
222=head2 TIME WATCHERS 232=head2 TIME WATCHERS
223 233
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
224You can create a time watcher by calling the C<< AnyEvent->timer >> 242You can create a time watcher by calling the C<< AnyEvent->timer >>
225method with the following mandatory arguments: 243method with the following mandatory arguments:
226 244
227C<after> specifies after how many seconds (fractional values are 245C<after> specifies after how many seconds (fractional values are
228supported) 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
230 248
231Although the callback might get passed parameters, their value and 249Although the callback might get passed parameters, their value and
232presence is undefined and you cannot rely on them. Portable AnyEvent 250presence is undefined and you cannot rely on them. Portable AnyEvent
233callbacks cannot use arguments passed to time watcher callbacks. 251callbacks cannot use arguments passed to time watcher callbacks.
234 252
235The callback will normally be invoked once only. If you specify another 253The callback will normally be invoked only once. If you specify another
236parameter, C<interval>, as a strictly positive number (> 0), then the 254parameter, C<interval>, as a strictly positive number (> 0), then the
237callback will be invoked regularly at that interval (in fractional 255callback will be invoked regularly at that interval (in fractional
238seconds) after the first invocation. If C<interval> is specified with a 256seconds) after the first invocation. If C<interval> is specified with a
239false value, then it is treated as if it were missing. 257false value, then it is treated as if it were not specified at all.
240 258
241The callback will be rescheduled before invoking the callback, but no 259The callback will be rescheduled before invoking the callback, but no
242attempt 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
243only approximate. 261only approximate.
244 262
245Example: fire an event after 7.7 seconds. 263Example: fire an event after 7.7 seconds.
246 264
247 my $w = AnyEvent->timer (after => 7.7, cb => sub { 265 my $w = AnyEvent->timer (after => 7.7, cb => sub {
265 283
266While 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
267use absolute time internally. This makes a difference when your clock 285use absolute time internally. This makes a difference when your clock
268"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
269the 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
270fire "after" a second might actually take six years to finally fire. 288fire "after a second" might actually take six years to finally fire.
271 289
272AnyEvent cannot compensate for this. The only event loop that is conscious 290AnyEvent cannot compensate for this. The only event loop that is conscious
273about 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
274on true relative time) and absolute (ev_periodic, based on wallclock time) 292on true relative time) and absolute (ev_periodic, based on wallclock time)
275timers. 293timers.
276 294
277AnyEvent always prefers relative timers, if available, matching the 295AnyEvent always prefers relative timers, if available, matching the
278AnyEvent API. 296AnyEvent API.
300I<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
301function to call when you want to know the current time.> 319function to call when you want to know the current time.>
302 320
303This function is also often faster then C<< AnyEvent->time >>, and 321This function is also often faster then C<< AnyEvent->time >>, and
304thus the preferred method if you want some timestamp (for example, 322thus the preferred method if you want some timestamp (for example,
305L<AnyEvent::Handle> uses this to update it's activity timeouts). 323L<AnyEvent::Handle> uses this to update its activity timeouts).
306 324
307The 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
308with your timing, you can skip it without bad conscience. 326with your timing; you can skip it without a bad conscience.
309 327
310For 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>
311and L<EV> and the following set-up: 329and L<EV> and the following set-up:
312 330
313The 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
314time=500 (assume no other callbacks delay processing). In your callback, 332time=500 (assume no other callbacks delay processing). In your callback,
315you 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
316second) 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
317after three seconds. 335after three seconds.
318 336
338difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 356difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
339account. 357account.
340 358
341=item AnyEvent->now_update 359=item AnyEvent->now_update
342 360
343Some 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
344the current time for each loop iteration (see the discussion of L<< 362time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
345AnyEvent->now >>, above). 363above).
346 364
347When 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
348this "current" time will differ substantially from the real time, which 366this "current" time will differ substantially from the real time, which
349might affect timers and time-outs. 367might affect timers and time-outs.
350 368
351When 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
352event loop's idea of "current time". 370event loop's idea of "current time".
353 371
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
354Note 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.
355 380
356=back 381=back
357 382
358=head2 SIGNAL WATCHERS 383=head2 SIGNAL WATCHERS
384
385 $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
359 386
360You 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
361I<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
362callback to be invoked whenever a signal occurs. 389callback to be invoked whenever a signal occurs.
363 390
380 407
381Example: exit on SIGINT 408Example: exit on SIGINT
382 409
383 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); 410 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384 411
412=head3 Restart Behaviour
413
414While restart behaviour is up to the event loop implementation, most will
415not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
416pure perl implementation).
417
418=head3 Safe/Unsafe Signals
419
420Perl signals can be either "safe" (synchronous to opcode handling)
421or "unsafe" (asynchronous) - the former might delay signal delivery
422indefinitely, the latter might corrupt your memory.
423
424AnyEvent signal handlers are, in addition, synchronous to the event loop,
425i.e. they will not interrupt your running perl program but will only be
426called as part of the normal event handling (just like timer, I/O etc.
427callbacks, too).
428
385=head3 Signal Races, Delays and Workarounds 429=head3 Signal Races, Delays and Workarounds
386 430
387Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching 431Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
388callbacks to signals in a generic way, which is a pity, as you cannot do 432attaching callbacks to signals in a generic way, which is a pity,
389race-free signal handling in perl. AnyEvent will try to do it's best, but 433as you cannot do race-free signal handling in perl, requiring
434C libraries for this. AnyEvent will try to do its best, which
390in some cases, signals will be delayed. The maximum time a signal might 435means in some cases, signals will be delayed. The maximum time
391be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 436a signal might be delayed is 10 seconds by default, but can
392seconds). This variable can be changed only before the first signal 437be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
393watcher is created, and should be left alone otherwise. Higher values 438C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
394will cause fewer spurious wake-ups, which is better for power and CPU 439section for details.
440
395saving. All these problems can be avoided by installing the optional 441All these problems can be avoided by installing the optional
396L<Async::Interrupt> module. This will not work with inherently broken 442L<Async::Interrupt> module, which works with most event loops. It will not
397event 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>
398currently, 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
399those, you just have to suffer the delays. 445delays.
400 446
401=head2 CHILD PROCESS WATCHERS 447=head2 CHILD PROCESS WATCHERS
402 448
449 $w = AnyEvent->child (pid => <process id>, cb => <callback>);
450
403You 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.
404 452
405The child process is specified by the C<pid> argument (one some backends, 453The child process is specified by the C<pid> argument (on some backends,
406using C<0> watches for any child process exit, on others this will 454using C<0> watches for any child process exit, on others this will
407croak). The watcher will be triggered only when the child process has 455croak). The watcher will be triggered only when the child process has
408finished and an exit status is available, not on any trace events 456finished and an exit status is available, not on any trace events
409(stopped/continued). 457(stopped/continued).
410 458
432thing 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
433watcher before you C<fork> the child (alternatively, you can call 481watcher before you C<fork> the child (alternatively, you can call
434C<AnyEvent::detect>). 482C<AnyEvent::detect>).
435 483
436As 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
437emulated 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
438mentioned in the description of signal watchers apply. 486problems mentioned in the description of signal watchers apply.
439 487
440Example: fork a process and wait for it 488Example: fork a process and wait for it
441 489
442 my $done = AnyEvent->condvar; 490 my $done = AnyEvent->condvar;
443 491
455 # do something else, then wait for process exit 503 # do something else, then wait for process exit
456 $done->recv; 504 $done->recv;
457 505
458=head2 IDLE WATCHERS 506=head2 IDLE WATCHERS
459 507
460Sometimes there is a need to do something, but it is not so important 508 $w = AnyEvent->idle (cb => <callback>);
461to do it instantly, but only when there is nothing better to do. This
462"nothing better to do" is usually defined to be "no other events need
463attention by the event loop".
464 509
465Idle watchers ideally get invoked when the event loop has nothing 510This will repeatedly invoke the callback after the process becomes idle,
466better 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.
467events. Instead of blocking, the idle watcher is invoked.
468 512
469Most 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
470EV, 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
471will simply call the callback "from time to time". 524will simply call the callback "from time to time".
472 525
473Example: read lines from STDIN, but only process them when the 526Example: read lines from STDIN, but only process them when the
474program is otherwise idle: 527program is otherwise idle:
490 }); 543 });
491 }); 544 });
492 545
493=head2 CONDITION VARIABLES 546=head2 CONDITION VARIABLES
494 547
548 $cv = AnyEvent->condvar;
549
550 $cv->send (<list>);
551 my @res = $cv->recv;
552
495If 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
496require you to run some blocking "loop", "run" or similar function that 554require you to run some blocking "loop", "run" or similar function that
497will actively watch for new events and call your callbacks. 555will actively watch for new events and call your callbacks.
498 556
499AnyEvent is slightly different: it expects somebody else to run the event 557AnyEvent is slightly different: it expects somebody else to run the event
500loop 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).
501 559
502The instrument to do that is called a "condition variable", so called 560The tool to do that is called a "condition variable", so called because
503because they represent a condition that must become true. 561they represent a condition that must become true.
504 562
505Now 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.
506 564
507Condition variables can be created by calling the C<< AnyEvent->condvar 565Condition variables can be created by calling the C<< AnyEvent->condvar
508>> method, usually without arguments. The only argument pair allowed is 566>> method, usually without arguments. The only argument pair allowed is
513After creation, the condition variable is "false" until it becomes "true" 571After creation, the condition variable is "false" until it becomes "true"
514by 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
515were 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<<
516->send >> method). 574->send >> method).
517 575
518Condition variables are similar to callbacks, except that you can 576Since condition variables are the most complex part of the AnyEvent API, here are
519optionally 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:
520in time where multiple outstanding events have been processed. And yet 578
521another way to call them is transactions - each condition variable can be 579=over 4
522used to represent a transaction, which finishes at some point and delivers 580
523a result. And yet some people know them as "futures" - a promise to 581=item * Condition variables are like callbacks - you can call them (and pass them instead
524compute/deliver something that you can wait for. 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
525 599
526Condition variables are very useful to signal that something has finished, 600Condition variables are very useful to signal that something has finished,
527for example, if you write a module that does asynchronous http requests, 601for example, if you write a module that does asynchronous http requests,
528then a condition variable would be the ideal candidate to signal the 602then a condition variable would be the ideal candidate to signal the
529availability of results. The user can either act when the callback is 603availability of results. The user can either act when the callback is
542 616
543Condition variables are represented by hash refs in perl, and the keys 617Condition variables are represented by hash refs in perl, and the keys
544used 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
545easy (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
546AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call 620AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
547it's C<new> method in your own C<new> method. 621its C<new> method in your own C<new> method.
548 622
549There are two "sides" to a condition variable - the "producer side" which 623There are two "sides" to a condition variable - the "producer side" which
550eventually calls C<< -> send >>, and the "consumer side", which waits 624eventually calls C<< -> send >>, and the "consumer side", which waits
551for the send to occur. 625for the send to occur.
552 626
553Example: wait for a timer. 627Example: wait for a timer.
554 628
555 # wait till the result is ready 629 # condition: "wait till the timer is fired"
556 my $result_ready = AnyEvent->condvar; 630 my $timer_fired = AnyEvent->condvar;
557 631
558 # do something such as adding a timer 632 # create the timer - we could wait for, say
559 # or socket watcher the calls $result_ready->send 633 # a handle becomign ready, or even an
560 # when the "result" is ready. 634 # AnyEvent::HTTP request to finish, but
561 # in this case, we simply use a timer: 635 # in this case, we simply use a timer:
562 my $w = AnyEvent->timer ( 636 my $w = AnyEvent->timer (
563 after => 1, 637 after => 1,
564 cb => sub { $result_ready->send }, 638 cb => sub { $timer_fired->send },
565 ); 639 );
566 640
567 # this "blocks" (while handling events) till the callback 641 # this "blocks" (while handling events) till the callback
568 # calls -<send 642 # calls ->send
569 $result_ready->recv; 643 $timer_fired->recv;
570 644
571Example: 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
572variables are also callable directly. 646variables are also callable directly.
573 647
574 my $done = AnyEvent->condvar; 648 my $done = AnyEvent->condvar;
617they 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
618C<send>. 692C<send>.
619 693
620=item $cv->croak ($error) 694=item $cv->croak ($error)
621 695
622Similar to send, but causes all call's to C<< ->recv >> to invoke 696Similar to send, but causes all calls to C<< ->recv >> to invoke
623C<Carp::croak> with the given error message/object/scalar. 697C<Carp::croak> with the given error message/object/scalar.
624 698
625This can be used to signal any errors to the condition variable 699This can be used to signal any errors to the condition variable
626user/consumer. Doing it this way instead of calling C<croak> directly 700user/consumer. Doing it this way instead of calling C<croak> directly
627delays the error detetcion, but has the overwhelmign advantage that it 701delays the error detection, but has the overwhelming advantage that it
628diagnoses 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
629deep in some event clalback without connection to the actual code causing 703deep in some event callback with no connection to the actual code causing
630the problem. 704the problem.
631 705
632=item $cv->begin ([group callback]) 706=item $cv->begin ([group callback])
633 707
634=item $cv->end 708=item $cv->end
637one. 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
638to use a condition variable for the whole process. 712to use a condition variable for the whole process.
639 713
640Every 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
641C<< ->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
642>>, 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
643is 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
644callback 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.
645 720
646You 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
647sends), 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
648condition (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).
649 724
671one 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
672sending. 747sending.
673 748
674The ping example mentioned above is slightly more complicated, as the 749The ping example mentioned above is slightly more complicated, as the
675there 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
676begung can potentially be zero: 751begun can potentially be zero:
677 752
678 my $cv = AnyEvent->condvar; 753 my $cv = AnyEvent->condvar;
679 754
680 my %result; 755 my %result;
681 $cv->begin (sub { $cv->send (\%result) }); 756 $cv->begin (sub { shift->send (\%result) });
682 757
683 for my $host (@list_of_hosts) { 758 for my $host (@list_of_hosts) {
684 $cv->begin; 759 $cv->begin;
685 ping_host_then_call_callback $host, sub { 760 ping_host_then_call_callback $host, sub {
686 $result{$host} = ...; 761 $result{$host} = ...;
688 }; 763 };
689 } 764 }
690 765
691 $cv->end; 766 $cv->end;
692 767
768 ...
769
770 my $results = $cv->recv;
771
693This code fragment supposedly pings a number of hosts and calls 772This code fragment supposedly pings a number of hosts and calls
694C<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
695order. 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
696each 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
697it. 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
702to 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
703C<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
704doesn't execute once). 783doesn't execute once).
705 784
706This is the general pattern when you "fan out" into multiple (but 785This is the general pattern when you "fan out" into multiple (but
707potentially 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
708the 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
709subrequest you start, call C<begin> and for each subrequest you finish, 788subrequest you start, call C<begin> and for each subrequest you finish,
710call C<end>. 789call C<end>.
711 790
712=back 791=back
719=over 4 798=over 4
720 799
721=item $cv->recv 800=item $cv->recv
722 801
723Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 802Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
724>> methods have been called on c<$cv>, while servicing other watchers 803>> methods have been called on C<$cv>, while servicing other watchers
725normally. 804normally.
726 805
727You 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
728will return immediately. 807will return immediately.
729 808
732 811
733In list context, all parameters passed to C<send> will be returned, 812In list context, all parameters passed to C<send> will be returned,
734in scalar context only the first one will be returned. 813in scalar context only the first one will be returned.
735 814
736Note 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
737event loop, that is, recursive invocation of a blocking C<< ->recv 816event loop, that is, recursive invocation of a blocking C<< ->recv >> is
738>> 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
739condition is detected. This condition can be slightly loosened by using 818detected. This requirement can be dropped by relying on L<Coro::AnyEvent>
740L<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
741any 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.
742 825
743Not 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
744(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
745using 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
746caller 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
747condition variables with some kind of request results and supporting 830condition variables with some kind of request results and supporting
748callbacks so the caller knows that getting the result will not block, 831callbacks so the caller knows that getting the result will not block,
749while still supporting blocking waits if the caller so desires). 832while still supporting blocking waits if the caller so desires).
750 833
751You 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
752only calling C<< ->recv >> from within that callback (or at a later 835only calling C<< ->recv >> from within that callback (or at a later
753time). 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
754waits otherwise. 837waits otherwise.
755 838
756=item $bool = $cv->ready 839=item $bool = $cv->ready
762 845
763This is a mutator function that returns the callback set and optionally 846This is a mutator function that returns the callback set and optionally
764replaces it before doing so. 847replaces it before doing so.
765 848
766The 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
767C<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
768variable itself. Calling C<recv> inside the callback or at any later time 851condition variable itself. If the condition is already true, the
769is 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.
770 854
771=back 855=back
772 856
773=head1 SUPPORTED EVENT LOOPS/BACKENDS 857=head1 SUPPORTED EVENT LOOPS/BACKENDS
774 858
777=over 4 861=over 4
778 862
779=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.
780 864
781EV 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
782use. 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
783that, will fall back to its own pure-perl implementation, which is 867pure-perl implementation, which is available everywhere as it comes with
784available everywhere as it comes with AnyEvent itself. 868AnyEvent itself.
785 869
786 AnyEvent::Impl::EV based on EV (interface to libev, best choice). 870 AnyEvent::Impl::EV based on EV (interface to libev, best choice).
787 AnyEvent::Impl::Event based on Event, very stable, few glitches.
788 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 871 AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
789 872
790=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.
791 874
792These 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
793is 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
794them. This means that AnyEvent will automatically pick the right backend 877them. This means that AnyEvent will automatically pick the right backend
795when the main program loads an event module before anything starts to 878when the main program loads an event module before anything starts to
796create watchers. Nothing special needs to be done by the main program. 879create watchers. Nothing special needs to be done by the main program.
797 880
881 AnyEvent::Impl::Event based on Event, very stable, few glitches.
798 AnyEvent::Impl::Glib based on Glib, slow but very stable. 882 AnyEvent::Impl::Glib based on Glib, slow but very stable.
799 AnyEvent::Impl::Tk based on Tk, very broken. 883 AnyEvent::Impl::Tk based on Tk, very broken.
800 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 884 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
801 AnyEvent::Impl::POE based on POE, very slow, some limitations. 885 AnyEvent::Impl::POE based on POE, very slow, some limitations.
802 AnyEvent::Impl::Irssi used when running within irssi. 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).
803 890
804=item Backends with special needs. 891=item Backends with special needs.
805 892
806Qt requires the Qt::Application to be instantiated first, but will 893Qt requires the Qt::Application to be instantiated first, but will
807otherwise be picked up automatically. As long as the main program 894otherwise be picked up automatically. As long as the main program
808instantiates the application before any AnyEvent watchers are created, 895instantiates the application before any AnyEvent watchers are created,
809everything should just work. 896everything should just work.
810 897
811 AnyEvent::Impl::Qt based on Qt. 898 AnyEvent::Impl::Qt based on Qt.
812 899
813Support for IO::Async can only be partial, as it is too broken and
814architecturally limited to even support the AnyEvent API. It also
815is the only event loop that needs the loop to be set explicitly, so
816it can only be used by a main program knowing about AnyEvent. See
817L<AnyEvent::Impl::Async> for the gory details.
818
819 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
820
821=item Event loops that are indirectly supported via other backends. 900=item Event loops that are indirectly supported via other backends.
822 901
823Some event loops can be supported via other modules: 902Some event loops can be supported via other modules:
824 903
825There is no direct support for WxWidgets (L<Wx>) or L<Prima>. 904There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
850Contains C<undef> until the first watcher is being created, before the 929Contains C<undef> until the first watcher is being created, before the
851backend has been autodetected. 930backend has been autodetected.
852 931
853Afterwards 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
854name 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
855of 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
856case 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
857will be C<urxvt::anyevent>). 936will be C<urxvt::anyevent>).
858 937
859=item AnyEvent::detect 938=item AnyEvent::detect
860 939
861Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 940Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
862if necessary. You should only call this function right before you would 941if necessary. You should only call this function right before you would
863have 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
864runtime, 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).
865 948
866If you need to do some initialisation before AnyEvent watchers are 949If you need to do some initialisation before AnyEvent watchers are
867created, use C<post_detect>. 950created, use C<post_detect>.
868 951
869=item $guard = AnyEvent::post_detect { BLOCK } 952=item $guard = AnyEvent::post_detect { BLOCK }
870 953
871Arranges for the code block to be executed as soon as the event model is 954Arranges for the code block to be executed as soon as the event model is
872autodetected (or immediately if this has already happened). 955autodetected (or immediately if that has already happened).
873 956
874The block will be executed I<after> the actual backend has been detected 957The block will be executed I<after> the actual backend has been detected
875(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been 958(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
876created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do 959created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
877other initialisations - see the sources of L<AnyEvent::Strict> or 960other initialisations - see the sources of L<AnyEvent::Strict> or
886that automatically removes the callback again when it is destroyed (or 969that automatically removes the callback again when it is destroyed (or
887C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for 970C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
888a case where this is useful. 971a case where this is useful.
889 972
890Example: Create a watcher for the IO::AIO module and store it in 973Example: Create a watcher for the IO::AIO module and store it in
891C<$WATCHER>. Only do so after the event loop is initialised, though. 974C<$WATCHER>, but do so only do so after the event loop is initialised.
892 975
893 our WATCHER; 976 our WATCHER;
894 977
895 my $guard = AnyEvent::post_detect { 978 my $guard = AnyEvent::post_detect {
896 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); 979 $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
904 $WATCHER ||= $guard; 987 $WATCHER ||= $guard;
905 988
906=item @AnyEvent::post_detect 989=item @AnyEvent::post_detect
907 990
908If there are any code references in this array (you can C<push> to it 991If there are any code references in this array (you can C<push> to it
909before or after loading AnyEvent), then they will called directly after 992before or after loading AnyEvent), then they will be called directly
910the event loop has been chosen. 993after the event loop has been chosen.
911 994
912You should check C<$AnyEvent::MODEL> before adding to this array, though: 995You should check C<$AnyEvent::MODEL> before adding to this array, though:
913if 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
914array will be ignored. 997array will be ignored.
915 998
916Best use C<AnyEvent::post_detect { BLOCK }> when your application allows 999Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
917it,as it takes care of these details. 1000it, as it takes care of these details.
918 1001
919This variable is mainly useful for modules that can do something useful 1002This variable is mainly useful for modules that can do something useful
920when 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
921not 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
922into AnyEvent passively, without loading it. 1005into AnyEvent passively, without loading it.
923 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
924=back 1078=back
925 1079
926=head1 WHAT TO DO IN A MODULE 1080=head1 WHAT TO DO IN A MODULE
927 1081
928As 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
938because 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
939events is to stay interactive. 1093events is to stay interactive.
940 1094
941It 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
942requests 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
943called C<results> that returns the results, it should call C<< ->recv >> 1097called C<results> that returns the results, it may call C<< ->recv >>
944freely, 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).
945 1099
946=head1 WHAT TO DO IN THE MAIN PROGRAM 1100=head1 WHAT TO DO IN THE MAIN PROGRAM
947 1101
948There 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
949dictate which event model to use. 1103dictate which event model to use.
950 1104
951If 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
952do 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
953decide 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.
954 1110
955If 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
956Gtk2 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
957event module before loading AnyEvent or any module that uses it: generally 1113event module before loading AnyEvent or any module that uses it: generally
958speaking, 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
959modules might create watchers when they are loaded, and AnyEvent will 1115modules might create watchers when they are loaded, and AnyEvent will
960decide 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
961might chose the wrong one unless you load the correct one yourself. 1117might choose the wrong one unless you load the correct one yourself.
962 1118
963You can chose to use a pure-perl implementation by loading the 1119You can chose to use a pure-perl implementation by loading the
964C<AnyEvent::Impl::Perl> module, which gives you similar behaviour 1120C<AnyEvent::Loop> module, which gives you similar behaviour
965everywhere, but letting AnyEvent chose the model is generally better. 1121everywhere, but letting AnyEvent chose the model is generally better.
966 1122
967=head2 MAINLOOP EMULATION 1123=head2 MAINLOOP EMULATION
968 1124
969Sometimes (often for short test scripts, or even standalone programs who 1125Sometimes (often for short test scripts, or even standalone programs who
982 1138
983 1139
984=head1 OTHER MODULES 1140=head1 OTHER MODULES
985 1141
986The following is a non-exhaustive list of additional modules that use 1142The following is a non-exhaustive list of additional modules that use
987AnyEvent as a client and can therefore be mixed easily with other AnyEvent 1143AnyEvent as a client and can therefore be mixed easily with other
988modules 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
989come 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 :)
990 1149
991=over 4 1150=over 4
992 1151
993=item L<AnyEvent::Util> 1152=item L<AnyEvent::Util>
994 1153
995Contains various utility functions that replace often-used but blocking 1154Contains various utility functions that replace often-used blocking
996functions such as C<inet_aton> by event-/callback-based versions. 1155functions such as C<inet_aton> with event/callback-based versions.
997 1156
998=item L<AnyEvent::Socket> 1157=item L<AnyEvent::Socket>
999 1158
1000Provides various utility functions for (internet protocol) sockets, 1159Provides various utility functions for (internet protocol) sockets,
1001addresses and name resolution. Also functions to create non-blocking tcp 1160addresses and name resolution. Also functions to create non-blocking tcp
1003 1162
1004=item L<AnyEvent::Handle> 1163=item L<AnyEvent::Handle>
1005 1164
1006Provide read and write buffers, manages watchers for reads and writes, 1165Provide read and write buffers, manages watchers for reads and writes,
1007supports 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
1008non-blocking SSL/TLS (via L<AnyEvent::TLS>. 1167non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1009 1168
1010=item L<AnyEvent::DNS> 1169=item L<AnyEvent::DNS>
1011 1170
1012Provides rich asynchronous DNS resolver capabilities. 1171Provides rich asynchronous DNS resolver capabilities.
1013 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
1014=item L<AnyEvent::HTTP> 1179=item L<AnyEvent::AIO>
1015 1180
1016A 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
1017HTTP 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.
1018 1203
1019=item L<AnyEvent::HTTPD> 1204=item L<AnyEvent::HTTPD>
1020 1205
1021Provides a simple web application server framework. 1206A simple embedded webserver.
1022 1207
1023=item L<AnyEvent::FastPing> 1208=item L<AnyEvent::FastPing>
1024 1209
1025The fastest ping in the west. 1210The fastest ping in the west.
1026 1211
1027=item L<AnyEvent::DBI>
1028
1029Executes L<DBI> requests asynchronously in a proxy process.
1030
1031=item L<AnyEvent::AIO>
1032
1033Truly asynchronous I/O, should be in the toolbox of every event
1034programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1035together.
1036
1037=item L<AnyEvent::BDB>
1038
1039Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1040L<BDB> and AnyEvent together.
1041
1042=item L<AnyEvent::GPSD>
1043
1044A non-blocking interface to gpsd, a daemon delivering GPS information.
1045
1046=item L<AnyEvent::IRC>
1047
1048AnyEvent based IRC client module family (replacing the older Net::IRC3).
1049
1050=item L<AnyEvent::XMPP>
1051
1052AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1053Net::XMPP2>.
1054
1055=item L<AnyEvent::IGS>
1056
1057A non-blocking interface to the Internet Go Server protocol (used by
1058L<App::IGS>).
1059
1060=item L<Net::FCP>
1061
1062AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1063of AnyEvent.
1064
1065=item L<Event::ExecFlow>
1066
1067High level API for event-based execution flow control.
1068
1069=item L<Coro> 1212=item L<Coro>
1070 1213
1071Has 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 };
1072 1227
1073=back 1228=back
1074 1229
1075=cut 1230=cut
1076 1231
1077package AnyEvent; 1232package AnyEvent;
1078 1233
1079# basically a tuned-down version of common::sense 1234# basically a tuned-down version of common::sense
1080sub common_sense { 1235sub common_sense {
1081 # no warnings 1236 # from common:.sense 3.5
1082 ${^WARNING_BITS} ^= ${^WARNING_BITS}; 1237 local $^W;
1083 # 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)
1084 $^H |= 0x00000600; 1240 $^H |= 0x00000600;
1085} 1241}
1086 1242
1087BEGIN { AnyEvent::common_sense } 1243BEGIN { AnyEvent::common_sense }
1088 1244
1089use Carp (); 1245use Carp ();
1090 1246
1091our $VERSION = 4.881; 1247our $VERSION = '7.04';
1092our $MODEL; 1248our $MODEL;
1093
1094our $AUTOLOAD;
1095our @ISA; 1249our @ISA;
1096
1097our @REGISTRY; 1250our @REGISTRY;
1098
1099our $WIN32;
1100
1101our $VERBOSE; 1251our $VERBOSE;
1252our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1253our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1102 1254
1103BEGIN { 1255BEGIN {
1104 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; 1256 require "AnyEvent/constants.pl";
1257
1105 eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; 1258 eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1106 1259
1107 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} 1260 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1108 if ${^TAINT}; 1261 if ${^TAINT};
1109 1262
1110 $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; 1263 $ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
1264 for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1111 1265
1112} 1266 @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
1267 if ${^TAINT};
1113 1268
1114our $MAX_SIGNAL_LATENCY = 10; 1269 # $ENV{PERL_ANYEVENT_xxx} now valid
1115 1270
1116our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 1271 $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1117 1272
1118{
1119 my $idx; 1273 my $idx;
1120 $PROTOCOL{$_} = ++$idx 1274 $PROTOCOL{$_} = ++$idx
1121 for reverse split /\s*,\s*/, 1275 for reverse split /\s*,\s*/,
1122 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; 1276 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1123} 1277}
1124 1278
1279our @post_detect;
1280
1281sub post_detect(&) {
1282 my ($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
1125my @models = ( 1356our @models = (
1126 [EV:: => AnyEvent::Impl::EV:: , 1], 1357 [EV:: => AnyEvent::Impl::EV::],
1127 [Event:: => AnyEvent::Impl::Event::, 1], 1358 [AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1128 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1129 # everything below here will not (normally) be autoprobed 1359 # everything below here will not (normally) be autoprobed
1130 # as the pureperl backend should work everywhere 1360 # as the pure perl backend should work everywhere
1131 # 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
1132 [Glib:: => AnyEvent::Impl::Glib:: , 1], # 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
1133 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 1366 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1134 [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1135 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles 1367 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1136 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 1368 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1137 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 1369 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1138 [Wx:: => AnyEvent::Impl::POE::], 1370 [Wx:: => AnyEvent::Impl::POE::],
1139 [Prima:: => AnyEvent::Impl::POE::], 1371 [Prima:: => AnyEvent::Impl::POE::],
1140 # IO::Async is just too broken - we would need workarounds for its 1372 [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1141 # byzantine signal and broken child handling, among others. 1373 [Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1142 # IO::Async is rather hard to detect, as it doesn't have any 1374 [FLTK:: => AnyEvent::Impl::FLTK::],
1143 # obvious default class.
1144# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1145# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1146# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1147); 1375);
1148 1376
1149our %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, $reset_ae] : undef;
1394
1395 _isa_set;
1396}
1397
1398# all autoloaded methods reserve the complete glob, not just the method slot.
1399# due to bugs in perls method cache implementation.
1150 qw(io timer time now now_update signal child idle condvar one_event DESTROY); 1400our @methods = qw(io timer time now now_update signal child idle condvar);
1151 1401
1152our @post_detect;
1153
1154sub post_detect(&) { 1402sub detect() {
1155 my ($cb) = @_; 1403 return $MODEL if $MODEL; # some programs keep references to detect
1156 1404
1157 if ($MODEL) { 1405 # IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1158 $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"};
1159 1412
1160 undef 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;
1161 } else { 1432 } else {
1162 push @post_detect, $cb; 1433 AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1163 1434 }
1164 defined wantarray
1165 ? bless \$cb, "AnyEvent::Util::postdetect"
1166 : ()
1167 } 1435 }
1168}
1169 1436
1170sub AnyEvent::Util::postdetect::DESTROY { 1437 # check for already loaded models
1171 @post_detect = grep $_ != ${$_[0]}, @post_detect;
1172}
1173
1174sub detect() {
1175 unless ($MODEL) { 1438 unless ($MODEL) {
1176 local $SIG{__DIE__}; 1439 for (@REGISTRY, @models) {
1177 1440 my ($package, $model) = @$_;
1178 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 1441 if (${"$package\::VERSION"} > 0) {
1179 my $model = "AnyEvent::Impl::$1";
1180 if (eval "require $model") { 1442 if (eval "require $model") {
1443 AnyEvent::log 7 => "Autodetected model '$model', using it.";
1181 $MODEL = $model; 1444 $MODEL = $model;
1182 warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; 1445 last;
1183 } else { 1446 } else {
1184 warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; 1447 AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
1448 }
1185 } 1449 }
1186 } 1450 }
1187 1451
1188 # check for already loaded models
1189 unless ($MODEL) { 1452 unless ($MODEL) {
1453 # try to autoload a model
1190 for (@REGISTRY, @models) { 1454 for (@REGISTRY, @models) {
1191 my ($package, $model) = @$_; 1455 my ($package, $model) = @$_;
1456 if (
1457 eval "require $package"
1192 if (${"$package\::VERSION"} > 0) { 1458 and ${"$package\::VERSION"} > 0
1193 if (eval "require $model") { 1459 and eval "require $model"
1460 ) {
1461 AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1194 $MODEL = $model; 1462 $MODEL = $model;
1195 warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1196 last; 1463 last;
1197 }
1198 } 1464 }
1199 } 1465 }
1200 1466
1201 unless ($MODEL) {
1202 # try to autoload a model
1203 for (@REGISTRY, @models) {
1204 my ($package, $model, $autoload) = @$_;
1205 if (
1206 $autoload
1207 and eval "require $package"
1208 and ${"$package\::VERSION"} > 0
1209 and eval "require $model"
1210 ) {
1211 $MODEL = $model;
1212 warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1213 last;
1214 }
1215 }
1216
1217 $MODEL 1467 $MODEL
1218 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; 1468 or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1219 }
1220 } 1469 }
1221
1222 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1223
1224 unshift @ISA, $MODEL;
1225
1226 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1227
1228 (shift @post_detect)->() while @post_detect;
1229 } 1470 }
1230 1471
1472 # free memory only needed for probing
1473 undef @models;
1474 undef @REGISTRY;
1475
1476 push @{"$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
1231 $MODEL 1521 $MODEL
1232} 1522}
1233 1523
1234sub AUTOLOAD { 1524for my $name (@methods) {
1235 (my $func = $AUTOLOAD) =~ s/.*://; 1525 *$name = sub {
1236 1526 detect;
1237 $method{$func} 1527 # we use goto because
1238 or Carp::croak "$func: not a valid method for AnyEvent objects"; 1528 # a) it makes the thunk more transparent
1239 1529 # b) it allows us to delete the thunk later
1240 detect unless $MODEL; 1530 goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1241 1531 };
1242 my $class = shift;
1243 $class->$func (@_);
1244} 1532}
1245 1533
1246# 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
1247# to support binding more than one watcher per filehandle (they usually 1535# to support binding more than one watcher per filehandle (they usually
1248# 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).
1258 # 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
1259 1547
1260 ($fh2, $rw) 1548 ($fh2, $rw)
1261} 1549}
1262 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
1263package AnyEvent::Base; 1614package AnyEvent::Base;
1264 1615
1265# default implementations for many methods 1616# default implementations for many methods
1266 1617
1267sub _time { 1618sub time {
1619 eval q{ # poor man's autoloading {}
1268 # probe for availability of Time::HiRes 1620 # probe for availability of Time::HiRes
1269 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { 1621 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1270 warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; 1622 *time = sub { Time::HiRes::time () };
1271 *_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.";
1272 # if (eval "use POSIX (); (POSIX::times())... 1626 # if (eval "use POSIX (); (POSIX::times())...
1273 } else { 1627 } else {
1274 warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; 1628 *time = sub { CORE::time };
1275 *_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 }
1276 } 1633 };
1634 die if $@;
1277 1635
1278 &_time 1636 &time
1279} 1637}
1280 1638
1281sub time { _time } 1639*now = \&time;
1282sub now { _time }
1283sub now_update { } 1640sub now_update { }
1284 1641
1642sub _poll {
1643 Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
1644}
1645
1285# default implementation for ->condvar 1646# default implementation for ->condvar
1647# in fact, the default should not be overwritten
1286 1648
1287sub condvar { 1649sub condvar {
1650 eval q{ # poor man's autoloading {}
1651 *condvar = sub {
1288 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
1289} 1662}
1290 1663
1291# default implementation for ->signal 1664# default implementation for ->signal
1292 1665
1293our $HAVE_ASYNC_INTERRUPT; 1666our $HAVE_ASYNC_INTERRUPT;
1294 1667
1295sub _have_async_interrupt() { 1668sub _have_async_interrupt() {
1296 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} 1669 $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1297 && eval "use Async::Interrupt 1.0 (); 1") 1670 && eval "use Async::Interrupt 1.02 (); 1")
1298 unless defined $HAVE_ASYNC_INTERRUPT; 1671 unless defined $HAVE_ASYNC_INTERRUPT;
1299 1672
1300 $HAVE_ASYNC_INTERRUPT 1673 $HAVE_ASYNC_INTERRUPT
1301} 1674}
1302 1675
1303our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1676our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1304our (%SIG_ASY, %SIG_ASY_W); 1677our (%SIG_ASY, %SIG_ASY_W);
1305our ($SIG_COUNT, $SIG_TW); 1678our ($SIG_COUNT, $SIG_TW);
1306 1679
1307sub _signal_exec {
1308 $HAVE_ASYNC_INTERRUPT
1309 ? $SIGPIPE_R->drain
1310 : sysread $SIGPIPE_R, my $dummy, 9;
1311
1312 while (%SIG_EV) {
1313 for (keys %SIG_EV) {
1314 delete $SIG_EV{$_};
1315 $_->() for values %{ $SIG_CB{$_} || {} };
1316 }
1317 }
1318}
1319
1320# install a dummy wakeup watcher to reduce signal catching latency 1680# install a dummy wakeup watcher to reduce signal catching latency
1681# used by Impls
1321sub _sig_add() { 1682sub _sig_add() {
1322 unless ($SIG_COUNT++) { 1683 unless ($SIG_COUNT++) {
1323 # try to align timer on a full-second boundary, if possible 1684 # try to align timer on a full-second boundary, if possible
1324 my $NOW = AnyEvent->now; 1685 my $NOW = AE::now;
1325 1686
1326 $SIG_TW = AnyEvent->timer ( 1687 $SIG_TW = AE::timer
1327 after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW), 1688 $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1328 interval => $MAX_SIGNAL_LATENCY, 1689 $MAX_SIGNAL_LATENCY,
1329 cb => sub { }, # just for the PERL_ASYNC_CHECK 1690 sub { } # just for the PERL_ASYNC_CHECK
1330 ); 1691 ;
1331 } 1692 }
1332} 1693}
1333 1694
1334sub _sig_del { 1695sub _sig_del {
1335 undef $SIG_TW 1696 undef $SIG_TW
1336 unless --$SIG_COUNT; 1697 unless --$SIG_COUNT;
1337} 1698}
1338 1699
1339our %SIGNAME2NUM;
1340our @SIGNUM2NAME;
1341our $_sig_name_init; $_sig_name_init = sub { 1700our $_sig_name_init; $_sig_name_init = sub {
1701 eval q{ # poor man's autoloading {}
1342 undef $_sig_name_init; 1702 undef $_sig_name_init;
1343 1703
1344 if (_have_async_interrupt) { 1704 if (_have_async_interrupt) {
1345 *sig2num = \&Async::Interrupt::sig2num; 1705 *sig2num = \&Async::Interrupt::sig2num;
1346 *sig2name = \&Async::Interrupt::sig2name; 1706 *sig2name = \&Async::Interrupt::sig2name;
1347 } else { 1707 } else {
1348 require Config; 1708 require Config;
1349 1709
1710 my %signame2num;
1350 @SIGNAME2NUM{ split ' ', $Config::Config{sig_name} } 1711 @signame2num{ split ' ', $Config::Config{sig_name} }
1351 = split ' ', $Config::Config{sig_num}; 1712 = split ' ', $Config::Config{sig_num};
1352 @SIGNUM2NAME[values %SIGNAME2NUM] = keys %SIGNAME2NUM;
1353 1713
1714 my @signum2name;
1715 @signum2name[values %signame2num] = keys %signame2num;
1716
1354 *sig2num = sub($) { 1717 *sig2num = sub($) {
1355 $_[0] > 0 ? shift : $SIGNAME2NUM{+shift} 1718 $_[0] > 0 ? shift : $signame2num{+shift}
1356 }; 1719 };
1357 *sig2name = sub ($) { 1720 *sig2name = sub ($) {
1358 $_[0] > 0 ? $SIGNUM2NAME[+shift] : shift 1721 $_[0] > 0 ? $signum2name[+shift] : shift
1722 };
1359 }; 1723 }
1360 } 1724 };
1725 die if $@;
1361}; 1726};
1362 1727
1363sub sig2num ($) { &$_sig_name_init; &sig2num } 1728sub sig2num ($) { &$_sig_name_init; &sig2num }
1364sub sig2name($) { &$_sig_name_init; &sig2name } 1729sub sig2name($) { &$_sig_name_init; &sig2name }
1365 1730
1366sub _signal { 1731sub signal {
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.";
1736
1737 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1738 $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1739
1740 } else {
1741 AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1742
1743 if (AnyEvent::WIN32) {
1744 require AnyEvent::Util;
1745
1746 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1747 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1748 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1749 } else {
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;
1757 }
1758
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 {
1367 my (undef, %arg) = @_; 1767 my (undef, %arg) = @_;
1368 1768
1369 my $signal = uc $arg{signal}
1370 or Carp::croak "required option 'signal' is missing";
1371
1372 if ($HAVE_ASYNC_INTERRUPT) {
1373 # async::interrupt 1769 # async::interrupt
1374
1375 $signal = sig2num $signal; 1770 my $signal = sig2num $arg{signal};
1376 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1771 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1377 1772
1378 $SIG_ASY{$signal} ||= new Async::Interrupt 1773 $SIG_ASY{$signal} ||= new Async::Interrupt
1379 cb => sub { undef $SIG_EV{$signal} }, 1774 cb => sub { undef $SIG_EV{$signal} },
1380 signal => $signal, 1775 signal => $signal,
1381 pipe => [$SIGPIPE_R->filenos], 1776 pipe => [$SIGPIPE_R->filenos],
1382 pipe_autodrain => 0, 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 }
1383 ; 1801 ;
1384 1802
1385 } else { 1803 *AnyEvent::Base::signal::DESTROY = sub {
1386 # pure perl 1804 my ($signal, $cb) = @{$_[0]};
1387 1805
1388 # AE::Util has been loaded in signal 1806 _sig_del;
1389 $signal = sig2name $signal;
1390 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1391 1807
1392 $SIG{$signal} ||= sub { 1808 delete $SIG_CB{$signal}{$cb};
1393 local $!; 1809
1394 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 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.
1395 undef $SIG_EV{$signal}; 1815 undef $SIG{$signal}
1816 unless keys %{ $SIG_CB{$signal} };
1396 }; 1817 };
1397 1818
1398 # can't do signal processing without introducing races in pure perl, 1819 *_signal_exec = sub {
1399 # so limit the signal latency. 1820 $HAVE_ASYNC_INTERRUPT
1400 _sig_add; 1821 ? $SIGPIPE_R->drain
1401 } 1822 : sysread $SIGPIPE_R, (my $dummy), 9;
1402 1823
1403 bless [$signal, $arg{cb}], "AnyEvent::Base::signal" 1824 while (%SIG_EV) {
1404} 1825 for (keys %SIG_EV) {
1405 1826 delete $SIG_EV{$_};
1406sub signal { 1827 &$_ for values %{ $SIG_CB{$_} || {} };
1407 # probe for availability of Async::Interrupt 1828 }
1408 if (_have_async_interrupt) { 1829 }
1409 warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1410
1411 $SIGPIPE_R = new Async::Interrupt::EventPipe;
1412 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1413
1414 } else {
1415 warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1416
1417 require Fcntl;
1418
1419 if (AnyEvent::WIN32) {
1420 require AnyEvent::Util;
1421
1422 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1423 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1424 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1425 } else {
1426 pipe $SIGPIPE_R, $SIGPIPE_W;
1427 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1428 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1429
1430 # not strictly required, as $^F is normally 2, but let's make sure...
1431 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1432 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1433 } 1830 };
1434
1435 $SIGPIPE_R
1436 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1437
1438 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1439 } 1831 };
1832 die if $@;
1440 1833
1441 *signal = \&_signal;
1442 &signal 1834 &signal
1443}
1444
1445sub AnyEvent::Base::signal::DESTROY {
1446 my ($signal, $cb) = @{$_[0]};
1447
1448 _sig_del;
1449
1450 delete $SIG_CB{$signal}{$cb};
1451
1452 $HAVE_ASYNC_INTERRUPT
1453 ? delete $SIG_ASY{$signal}
1454 : # delete doesn't work with older perls - they then
1455 # print weird messages, or just unconditionally exit
1456 # instead of getting the default action.
1457 undef $SIG{$signal}
1458 unless keys %{ $SIG_CB{$signal} };
1459} 1835}
1460 1836
1461# default implementation for ->child 1837# default implementation for ->child
1462 1838
1463our %PID_CB; 1839our %PID_CB;
1464our $CHLD_W; 1840our $CHLD_W;
1465our $CHLD_DELAY_W; 1841our $CHLD_DELAY_W;
1466our $WNOHANG;
1467 1842
1843# used by many Impl's
1468sub _emit_childstatus($$) { 1844sub _emit_childstatus($$) {
1469 my (undef, $rpid, $rstatus) = @_; 1845 my (undef, $rpid, $rstatus) = @_;
1470 1846
1471 $_->($rpid, $rstatus) 1847 $_->($rpid, $rstatus)
1472 for values %{ $PID_CB{$rpid} || {} }, 1848 for values %{ $PID_CB{$rpid} || {} },
1473 values %{ $PID_CB{0} || {} }; 1849 values %{ $PID_CB{0} || {} };
1474} 1850}
1475 1851
1476sub _sigchld {
1477 my $pid;
1478
1479 AnyEvent->_emit_childstatus ($pid, $?)
1480 while ($pid = waitpid -1, $WNOHANG) > 0;
1481}
1482
1483sub 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 {
1484 my (undef, %arg) = @_; 1862 my (undef, %arg) = @_;
1485 1863
1486 defined (my $pid = $arg{pid} + 0) 1864 my $pid = $arg{pid};
1487 or Carp::croak "required option 'pid' is missing"; 1865 my $cb = $arg{cb};
1488 1866
1489 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1867 $PID_CB{$pid}{$cb+0} = $cb;
1490 1868
1491 # WNOHANG is almost cetrainly 1 everywhere
1492 $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1493 ? 1
1494 : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1495
1496 unless ($CHLD_W) { 1869 unless ($CHLD_W) {
1497 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1870 $CHLD_W = AE::signal CHLD => \&_sigchld;
1498 # 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
1499 &_sigchld; 1872 &_sigchld;
1500 } 1873 }
1501 1874
1502 bless [$pid, $arg{cb}], "AnyEvent::Base::child" 1875 bless [$pid, $cb+0], "AnyEvent::Base::child"
1503} 1876 };
1504 1877
1505sub AnyEvent::Base::child::DESTROY { 1878 *AnyEvent::Base::child::DESTROY = sub {
1506 my ($pid, $cb) = @{$_[0]}; 1879 my ($pid, $icb) = @{$_[0]};
1507 1880
1508 delete $PID_CB{$pid}{$cb}; 1881 delete $PID_CB{$pid}{$icb};
1509 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1882 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1510 1883
1511 undef $CHLD_W unless keys %PID_CB; 1884 undef $CHLD_W unless keys %PID_CB;
1885 };
1886 };
1887 die if $@;
1888
1889 &child
1512} 1890}
1513 1891
1514# idle emulation is done by simply using a timer, regardless 1892# idle emulation is done by simply using a timer, regardless
1515# of whether the process is idle or not, and not letting 1893# of whether the process is idle or not, and not letting
1516# the callback use more than 50% of the time. 1894# the callback use more than 50% of the time.
1517sub idle { 1895sub idle {
1896 eval q{ # poor man's autoloading {}
1897 *idle = sub {
1518 my (undef, %arg) = @_; 1898 my (undef, %arg) = @_;
1519 1899
1520 my ($cb, $w, $rcb) = $arg{cb}; 1900 my ($cb, $w, $rcb) = $arg{cb};
1521 1901
1522 $rcb = sub { 1902 $rcb = sub {
1523 if ($cb) { 1903 if ($cb) {
1524 $w = _time; 1904 $w = AE::time;
1525 &$cb; 1905 &$cb;
1526 $w = _time - $w; 1906 $w = AE::time - $w;
1527 1907
1528 # 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,
1529 # within some limits 1909 # within some limits
1530 $w = 0.0001 if $w < 0.0001; 1910 $w = 0.0001 if $w < 0.0001;
1531 $w = 5 if $w > 5; 1911 $w = 5 if $w > 5;
1532 1912
1533 $w = AnyEvent->timer (after => $w, cb => $rcb); 1913 $w = AE::timer $w, 0, $rcb;
1534 } else { 1914 } else {
1535 # clean up... 1915 # clean up...
1536 undef $w; 1916 undef $w;
1537 undef $rcb; 1917 undef $rcb;
1918 }
1919 };
1920
1921 $w = AE::timer 0.05, 0, $rcb;
1922
1923 bless \\$cb, "AnyEvent::Base::idle"
1538 } 1924 };
1925
1926 *AnyEvent::Base::idle::DESTROY = sub {
1927 undef $${$_[0]};
1928 };
1539 }; 1929 };
1930 die if $@;
1540 1931
1541 $w = AnyEvent->timer (after => 0.05, cb => $rcb); 1932 &idle
1542
1543 bless \\$cb, "AnyEvent::Base::idle"
1544}
1545
1546sub AnyEvent::Base::idle::DESTROY {
1547 undef $${$_[0]};
1548} 1933}
1549 1934
1550package AnyEvent::CondVar; 1935package AnyEvent::CondVar;
1551 1936
1552our @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}
1553 1944
1554package AnyEvent::CondVar::Base; 1945package AnyEvent::CondVar::Base;
1555 1946
1556#use overload 1947#use overload
1557# '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, 1948# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1567 1958
1568sub _send { 1959sub _send {
1569 # nop 1960 # nop
1570} 1961}
1571 1962
1963sub _wait {
1964 AnyEvent->_poll until $_[0]{_ae_sent};
1965}
1966
1572sub send { 1967sub send {
1573 my $cv = shift; 1968 my $cv = shift;
1574 $cv->{_ae_sent} = [@_]; 1969 $cv->{_ae_sent} = [@_];
1575 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; 1970 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1576 $cv->_send; 1971 $cv->_send;
1583 1978
1584sub ready { 1979sub ready {
1585 $_[0]{_ae_sent} 1980 $_[0]{_ae_sent}
1586} 1981}
1587 1982
1588sub _wait {
1589 $WAITING
1590 and !$_[0]{_ae_sent}
1591 and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1592
1593 local $WAITING = 1;
1594 AnyEvent->one_event while !$_[0]{_ae_sent};
1595}
1596
1597sub 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;
1598 $_[0]->_wait; 1989 $_[0]->_wait;
1990 }
1599 1991
1600 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; 1992 $_[0]{_ae_croak}
1601 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]
1602} 1998}
1603 1999
1604sub cb { 2000sub cb {
1605 $_[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
1606 $_[0]{_ae_cb} 2008 $cv->{_ae_cb}
1607} 2009}
1608 2010
1609sub begin { 2011sub begin {
1610 ++$_[0]{_ae_counter}; 2012 ++$_[0]{_ae_counter};
1611 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 2013 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1616 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; 2018 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1617} 2019}
1618 2020
1619# undocumented/compatibility with pre-3.4 2021# undocumented/compatibility with pre-3.4
1620*broadcast = \&send; 2022*broadcast = \&send;
1621*wait = \&_wait; 2023*wait = \&recv;
1622 2024
1623=head1 ERROR AND EXCEPTION HANDLING 2025=head1 ERROR AND EXCEPTION HANDLING
1624 2026
1625In 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
1626caller 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
1638$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and 2040$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1639so on. 2041so on.
1640 2042
1641=head1 ENVIRONMENT VARIABLES 2043=head1 ENVIRONMENT VARIABLES
1642 2044
1643The following environment variables are used by this module or its 2045AnyEvent supports a number of environment variables that tune the
1644submodules. 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.
1645 2051
1646Note that AnyEvent will remove I<all> environment variables starting with 2052All the environment variables documented here start with
1647C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is 2053C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1648enabled. 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:
1649 2082
1650=over 4 2083=over 4
1651 2084
1652=item C<PERL_ANYEVENT_VERBOSE> 2085=item C<PERL_ANYEVENT_VERBOSE>
1653 2086
1654By default, AnyEvent will be completely silent except in fatal 2087By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1655conditions. You can set this environment variable to make AnyEvent more 2088higher (see L<AnyEvent::Log>). You can set this environment variable to a
1656talkative. 2089numerical loglevel to make AnyEvent more (or less) talkative.
1657 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
1658When 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
1659conditions, 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
1660C<PERL_ANYEVENT_MODEL>. 2100C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
2101is the minimum recommended level for use during development.
1661 2102
1662When 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
1663model it chooses. 2104chooses.
1664 2105
1665When 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
1666which 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.
1667 2127
1668=item C<PERL_ANYEVENT_STRICT> 2128=item C<PERL_ANYEVENT_STRICT>
1669 2129
1670AnyEvent does not do much argument checking by default, as thorough 2130AnyEvent does not do much argument checking by default, as thorough
1671argument checking is very costly. Setting this variable to a true value 2131argument checking is very costly. Setting this variable to a true value
1673check 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,
1674it will croak. 2134it will croak.
1675 2135
1676In other words, enables "strict" mode. 2136In other words, enables "strict" mode.
1677 2137
1678Unlike 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>
1679>>, it is definitely recommended to keep it off in production. Keeping 2139>>, it is definitely recommended to keep it off in production. Keeping
1680C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs 2140C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1681can be very useful, however. 2141can be very useful, however.
1682 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
1683=item C<PERL_ANYEVENT_MODEL> 2171=item C<PERL_ANYEVENT_MODEL>
1684 2172
1685This 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
1686auto detection and -probing kicks in. It must be a string consisting 2174auto detection and -probing kicks in.
1687entirely 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
1688and 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
1689used 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
1690auto detection and -probing. 2180auto detection and -probing.
1691 2181
1692This 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).
1693 2185
1694For 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
1695could start your program like this: 2187could start your program like this:
1696 2188
1697 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>.
1698 2198
1699=item C<PERL_ANYEVENT_PROTOCOLS> 2199=item C<PERL_ANYEVENT_PROTOCOLS>
1700 2200
1701Used 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
1702for 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
1715but 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>
1716- only support IPv4, never try to resolve or contact IPv6 2216- only support IPv4, never try to resolve or contact IPv6
1717addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 2217addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1718IPv6, but prefer IPv6 over IPv4. 2218IPv6, but prefer IPv6 over IPv4.
1719 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
1720=item C<PERL_ANYEVENT_EDNS0> 2226=item C<PERL_ANYEVENT_EDNS0>
1721 2227
1722Used 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
1723for DNS. This extension is generally useful to reduce DNS traffic, but 2229DNS. This extension is generally useful to reduce DNS traffic, especially
1724some (broken) firewalls drop such DNS packets, which is why it is off by 2230when DNSSEC is involved, but some (broken) firewalls drop such DNS
1725default. 2231packets, which is why it is off by default.
1726 2232
1727Setting 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
1728EDNS0 in its DNS requests. 2234EDNS0 in its DNS requests.
1729 2235
1730=item C<PERL_ANYEVENT_MAX_FORKS> 2236=item C<PERL_ANYEVENT_MAX_FORKS>
1736 2242
1737The 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
1738resolver - this is the maximum number of parallel DNS requests that are 2244resolver - this is the maximum number of parallel DNS requests that are
1739sent to the DNS server. 2245sent to the DNS server.
1740 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
1741=item C<PERL_ANYEVENT_RESOLV_CONF> 2269=item C<PERL_ANYEVENT_RESOLV_CONF>
1742 2270
1743The 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
1744configuration) in the default resolver. When set to the empty string, no 2272F</etc/resolv.conf> (or the OS-specific configuration) in the default
1745default config will be used. 2273resolver, or the empty string to select the default configuration.
1746 2274
1747=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. 2275=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1748 2276
1749When neither C<ca_file> nor C<ca_path> was specified during 2277When neither C<ca_file> nor C<ca_path> was specified during
1750L<AnyEvent::TLS> context creation, and either of these environment 2278L<AnyEvent::TLS> context creation, and either of these environment
1751variables exist, they will be used to specify CA certificate locations 2279variables are nonempty, they will be used to specify CA certificate
1752instead of a system-dependent default. 2280locations instead of a system-dependent default.
1753 2281
1754=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>
1755 2283
1756When 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
1757loaded. Mostly good for testing AnyEvent itself. 2285loaded. Mostly good for testing AnyEvent itself.
1820 warn "read: $input\n"; # output what has been read 2348 warn "read: $input\n"; # output what has been read
1821 $cv->send if $input =~ /^q/i; # quit program if /^q/i 2349 $cv->send if $input =~ /^q/i; # quit program if /^q/i
1822 }, 2350 },
1823 ); 2351 );
1824 2352
1825 my $time_watcher; # can only be used once
1826
1827 sub new_timer {
1828 $timer = AnyEvent->timer (after => 1, cb => sub { 2353 my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1829 warn "timeout\n"; # print 'timeout' about every second 2354 warn "timeout\n"; # print 'timeout' at most every second
1830 &new_timer; # and restart the time
1831 }); 2355 });
1832 }
1833
1834 new_timer; # create first timer
1835 2356
1836 $cv->recv; # wait until user enters /^q/i 2357 $cv->recv; # wait until user enters /^q/i
1837 2358
1838=head1 REAL-WORLD EXAMPLE 2359=head1 REAL-WORLD EXAMPLE
1839 2360
1912 2433
1913The 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)
1914that occurred during request processing. The C<result> method detects 2435that occurred during request processing. The C<result> method detects
1915whether an exception as thrown (it is stored inside the $txn object) 2436whether an exception as thrown (it is stored inside the $txn object)
1916and just throws the exception, which means connection errors and other 2437and just throws the exception, which means connection errors and other
1917problems 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
1918random callback. 2439random callback.
1919 2440
1920All of this enables the following usage styles: 2441All of this enables the following usage styles:
1921 2442
19221. Blocking: 24431. Blocking:
1970through AnyEvent. The benchmark creates a lot of timers (with a zero 2491through AnyEvent. The benchmark creates a lot of timers (with a zero
1971timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 2492timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1972which it is), lets them fire exactly once and destroys them again. 2493which it is), lets them fire exactly once and destroys them again.
1973 2494
1974Source 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
1975distribution. 2496distribution. It uses the L<AE> interface, which makes a real difference
2497for the EV and Perl backends only.
1976 2498
1977=head3 Explanation of the columns 2499=head3 Explanation of the columns
1978 2500
1979I<watcher> is the number of event watchers created/destroyed. Since 2501I<watcher> is the number of event watchers created/destroyed. Since
1980different event models feature vastly different performances, each event 2502different event models feature vastly different performances, each event
2001watcher. 2523watcher.
2002 2524
2003=head3 Results 2525=head3 Results
2004 2526
2005 name watchers bytes create invoke destroy comment 2527 name watchers bytes create invoke destroy comment
2006 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
2007 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
2008 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
2009 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
2010 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
2011 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
2012 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
2013 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
2014 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
2015 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
2016 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
2017 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
2018 2540
2019=head3 Discussion 2541=head3 Discussion
2020 2542
2021The benchmark does I<not> measure scalability of the event loop very 2543The benchmark does I<not> measure scalability of the event loop very
2022well. 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)
2034benchmark machine, handling an event takes roughly 1600 CPU cycles with 2556benchmark machine, handling an event takes roughly 1600 CPU cycles with
2035EV, 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
2036cycles with POE. 2558cycles with POE.
2037 2559
2038C<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
2039maximal/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
2040far less memory than any other event loop and is still faster than Event 2564any other event loop and is still faster than Event natively).
2041natively.
2042 2565
2043The 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
2044constant 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
2045interpreter and the backend itself). Nevertheless this shows that it 2568interpreter and the backend itself). Nevertheless this shows that it
2046adds very little overhead in itself. Like any select-based backend its 2569adds very little overhead in itself. Like any select-based backend its
2094(even when used without AnyEvent), but most event loops have acceptable 2617(even when used without AnyEvent), but most event loops have acceptable
2095performance with or without AnyEvent. 2618performance with or without AnyEvent.
2096 2619
2097=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
2098the 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
2099adds AnyEvent significant overhead. 2622does AnyEvent add significant overhead.
2100 2623
2101=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
2102reasonable memory usage. 2625reasonable memory usage.
2103 2626
2104=back 2627=back
2120In 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
2121(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
2122connections, most of which are idle at any one point in time. 2645connections, most of which are idle at any one point in time.
2123 2646
2124Source 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
2125distribution. 2648distribution. It uses the L<AE> interface, which makes a real difference
2649for the EV and Perl backends only.
2126 2650
2127=head3 Explanation of the columns 2651=head3 Explanation of the columns
2128 2652
2129I<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
2130each server has a read and write socket end). 2654each server has a read and write socket end).
2138a new one that moves the timeout into the future. 2662a new one that moves the timeout into the future.
2139 2663
2140=head3 Results 2664=head3 Results
2141 2665
2142 name sockets create request 2666 name sockets create request
2143 EV 20000 69.01 11.16 2667 EV 20000 62.66 7.99
2144 Perl 20000 73.32 35.87 2668 Perl 20000 68.32 32.64
2145 IOAsync 20000 157.00 98.14 epoll 2669 IOAsync 20000 174.06 101.15 epoll
2146 IOAsync 20000 159.31 616.06 poll 2670 IOAsync 20000 174.67 610.84 poll
2147 Event 20000 212.62 257.32 2671 Event 20000 202.69 242.91
2148 Glib 20000 651.16 1896.30 2672 Glib 20000 557.01 1689.52
2149 POE 20000 349.67 12317.24 uses POE::Loop::Event 2673 POE 20000 341.54 12086.32 uses POE::Loop::Event
2150 2674
2151=head3 Discussion 2675=head3 Discussion
2152 2676
2153This benchmark I<does> measure scalability and overall performance of the 2677This benchmark I<does> measure scalability and overall performance of the
2154particular event loop. 2678particular event loop.
2280As you can see, the AnyEvent + EV combination even beats the 2804As you can see, the AnyEvent + EV combination even beats the
2281hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl 2805hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2282backend easily beats IO::Lambda and POE. 2806backend easily beats IO::Lambda and POE.
2283 2807
2284And 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
2285slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a 2809slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2286large margin, even though it does all of DNS, tcp-connect and socket I/O 2810higher level ("unoptimised") abstractions by a large margin, even though
2287in a non-blocking way. 2811it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2288 2812
2289The 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
2290F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are 2814F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2291part of the IO::lambda distribution and were used without any changes. 2815part of the IO::Lambda distribution and were used without any changes.
2292 2816
2293 2817
2294=head1 SIGNALS 2818=head1 SIGNALS
2295 2819
2296AnyEvent currently installs handlers for these signals: 2820AnyEvent currently installs handlers for these signals:
2333 unless defined $SIG{PIPE}; 2857 unless defined $SIG{PIPE};
2334 2858
2335=head1 RECOMMENDED/OPTIONAL MODULES 2859=head1 RECOMMENDED/OPTIONAL MODULES
2336 2860
2337One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and 2861One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2338it's built-in modules) are required to use it. 2862its built-in modules) are required to use it.
2339 2863
2340That does not mean that AnyEvent won't take advantage of some additional 2864That does not mean that AnyEvent won't take advantage of some additional
2341modules if they are installed. 2865modules if they are installed.
2342 2866
2343This section epxlains which additional modules will be used, and how they 2867This section explains which additional modules will be used, and how they
2344affect AnyEvent's operetion. 2868affect AnyEvent's operation.
2345 2869
2346=over 4 2870=over 4
2347 2871
2348=item L<Async::Interrupt> 2872=item L<Async::Interrupt>
2349 2873
2354catch the signals) with some delay (default is 10 seconds, look for 2878catch the signals) with some delay (default is 10 seconds, look for
2355C<$AnyEvent::MAX_SIGNAL_LATENCY>). 2879C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2356 2880
2357If 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
2358catching, 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
2359will not be interrupted regularly, which is more efficient (And good for 2883will not be interrupted regularly, which is more efficient (and good for
2360battery life on laptops). 2884battery life on laptops).
2361 2885
2362This 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
2363that 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).
2364 2888
2376automatic timer adjustments even when no monotonic clock is available, 2900automatic timer adjustments even when no monotonic clock is available,
2377can take avdantage of advanced kernel interfaces such as C<epoll> and 2901can take avdantage of advanced kernel interfaces such as C<epoll> and
2378C<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
2379L<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>).
2380 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
2381=item L<Guard> 2908=item L<Guard>
2382 2909
2383The guard module, when used, will be used to implement 2910The guard module, when used, will be used to implement
2384C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a 2911C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2385lot 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
2386purely used for performance. 2913purely used for performance.
2387 2914
2388=item L<JSON> and L<JSON::XS> 2915=item L<JSON> and L<JSON::XS>
2389 2916
2390This 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
2391L<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
2392advantage 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.
2393
2394In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2395installed.
2396 2920
2397=item L<Net::SSLeay> 2921=item L<Net::SSLeay>
2398 2922
2399Implementing TLS/SSL in Perl is certainly interesting, but not very 2923Implementing TLS/SSL in Perl is certainly interesting, but not very
2400worthwhile: If this module is installed, then L<AnyEvent::Handle> (with 2924worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2401the 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.
2402 2926
2403=item L<Time::HiRes> 2927=item L<Time::HiRes>
2404 2928
2405This 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
2406chosen 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
2407pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to 2931pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2408try to use a monotonic clock for timing stability. 2932try to use a monotonic clock for timing stability.
2409 2933
2410=back 2934=back
2411 2935
2412 2936
2413=head1 FORK 2937=head1 FORK
2414 2938
2415Most event libraries are not fork-safe. The ones who are usually are 2939Most event libraries are not fork-safe. The ones who are usually are
2416because they rely on inefficient but fork-safe C<select> or C<poll> 2940because they rely on inefficient but fork-safe C<select> or C<poll> calls
2417calls. Only L<EV> is fully fork-aware. 2941- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
2942are usually badly thought-out hacks that are incompatible with fork in
2943one way or another. Only L<EV> is fully fork-aware and ensures that you
2944continue event-processing in both parent and child (or both, if you know
2945what you are doing).
2946
2947This means that, in general, you cannot fork and do event processing in
2948the child if the event library was initialised before the fork (which
2949usually happens when the first AnyEvent watcher is created, or the library
2950is loaded).
2418 2951
2419If you have to fork, you must either do so I<before> creating your first 2952If you have to fork, you must either do so I<before> creating your first
2420watcher OR you must not use AnyEvent at all in the child OR you must do 2953watcher OR you must not use AnyEvent at all in the child OR you must do
2421something completely out of the scope of AnyEvent. 2954something completely out of the scope of AnyEvent.
2955
2956The problem of doing event processing in the parent I<and> the child
2957is much more complicated: even for backends that I<are> fork-aware or
2958fork-safe, their behaviour is not usually what you want: fork clones all
2959watchers, that means all timers, I/O watchers etc. are active in both
2960parent and child, which is almost never what you want. USing C<exec>
2961to start worker children from some kind of manage rprocess is usually
2962preferred, because it is much easier and cleaner, at the expense of having
2963to have another binary.
2422 2964
2423 2965
2424=head1 SECURITY CONSIDERATIONS 2966=head1 SECURITY CONSIDERATIONS
2425 2967
2426AnyEvent can be forced to load any event model via 2968AnyEvent can be forced to load any event model via
2456pronounced). 2998pronounced).
2457 2999
2458 3000
2459=head1 SEE ALSO 3001=head1 SEE ALSO
2460 3002
2461Utility functions: L<AnyEvent::Util>. 3003Tutorial/Introduction: L<AnyEvent::Intro>.
2462 3004
2463Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 3005FAQ: L<AnyEvent::FAQ>.
2464L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 3006
3007Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
3008(simply logging).
3009
3010Development/Debugging: L<AnyEvent::Strict> (stricter checking),
3011L<AnyEvent::Debug> (interactive shell, watcher tracing).
3012
3013Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
3014L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
3015L<Qt>, L<POE>, L<FLTK>.
2465 3016
2466Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 3017Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2467L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 3018L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2468L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 3019L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2469L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>. 3020L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
3021L<AnyEvent::Impl::FLTK>.
2470 3022
2471Non-blocking file handles, sockets, TCP clients and 3023Non-blocking handles, pipes, stream sockets, TCP clients and
2472servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>. 3024servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2473 3025
3026Asynchronous File I/O: L<AnyEvent::IO>.
3027
2474Asynchronous DNS: L<AnyEvent::DNS>. 3028Asynchronous DNS: L<AnyEvent::DNS>.
2475 3029
2476Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, 3030Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2477L<Coro::Event>,
2478 3031
2479Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>, 3032Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2480L<AnyEvent::HTTP>. 3033L<AnyEvent::HTTP>.
2481 3034
2482 3035
2483=head1 AUTHOR 3036=head1 AUTHOR
2484 3037
2485 Marc Lehmann <schmorp@schmorp.de> 3038 Marc Lehmann <schmorp@schmorp.de>
2486 http://home.schmorp.de/ 3039 http://anyevent.schmorp.de
2487 3040
2488=cut 3041=cut
2489 3042
24901 30431
2491 3044

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