1 | NAME |
1 | NAME |
2 | AnyEvent - provide framework for multiple event loops |
2 | AnyEvent - the DBI of event loop programming |
3 | |
3 | |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, |
5 | event loops. |
5 | Qt and POE are various supported event loops/environments. |
6 | |
6 | |
7 | SYNOPSIS |
7 | SYNOPSIS |
8 | use AnyEvent; |
8 | use AnyEvent; |
9 | |
9 | |
10 | # file descriptor readable |
10 | # file descriptor readable |
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37 | |
37 | |
38 | INTRODUCTION/TUTORIAL |
38 | INTRODUCTION/TUTORIAL |
39 | This manpage is mainly a reference manual. If you are interested in a |
39 | This manpage is mainly a reference manual. If you are interested in a |
40 | tutorial or some gentle introduction, have a look at the AnyEvent::Intro |
40 | tutorial or some gentle introduction, have a look at the AnyEvent::Intro |
41 | manpage. |
41 | manpage. |
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42 | |
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43 | SUPPORT |
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44 | There is a mailinglist for discussing all things AnyEvent, and an IRC |
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45 | channel, too. |
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46 | |
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47 | See the AnyEvent project page at the Schmorpforge Ta-Sa Software |
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48 | Repository, at <http://anyevent.schmorp.de>, for more info. |
42 | |
49 | |
43 | WHY YOU SHOULD USE THIS MODULE (OR NOT) |
50 | WHY YOU SHOULD USE THIS MODULE (OR NOT) |
44 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
51 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
45 | nowadays. So what is different about AnyEvent? |
52 | nowadays. So what is different about AnyEvent? |
46 | |
53 | |
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166 | Note that "my $w; $w =" combination. This is necessary because in Perl, |
173 | Note that "my $w; $w =" combination. This is necessary because in Perl, |
167 | my variables are only visible after the statement in which they are |
174 | my variables are only visible after the statement in which they are |
168 | declared. |
175 | declared. |
169 | |
176 | |
170 | I/O WATCHERS |
177 | I/O WATCHERS |
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178 | $w = AnyEvent->io ( |
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179 | fh => <filehandle_or_fileno>, |
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180 | poll => <"r" or "w">, |
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181 | cb => <callback>, |
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182 | ); |
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183 | |
171 | You can create an I/O watcher by calling the "AnyEvent->io" method with |
184 | You can create an I/O watcher by calling the "AnyEvent->io" method with |
172 | the following mandatory key-value pairs as arguments: |
185 | the following mandatory key-value pairs as arguments: |
173 | |
186 | |
174 | "fh" is the Perl *file handle* (*not* file descriptor) to watch for |
187 | "fh" is the Perl *file handle* (or a naked file descriptor) to watch for |
175 | events (AnyEvent might or might not keep a reference to this file |
188 | events (AnyEvent might or might not keep a reference to this file |
176 | handle). Note that only file handles pointing to things for which |
189 | handle). Note that only file handles pointing to things for which |
177 | non-blocking operation makes sense are allowed. This includes sockets, |
190 | non-blocking operation makes sense are allowed. This includes sockets, |
178 | most character devices, pipes, fifos and so on, but not for example |
191 | most character devices, pipes, fifos and so on, but not for example |
179 | files or block devices. |
192 | files or block devices. |
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203 | warn "read: $input\n"; |
216 | warn "read: $input\n"; |
204 | undef $w; |
217 | undef $w; |
205 | }); |
218 | }); |
206 | |
219 | |
207 | TIME WATCHERS |
220 | TIME WATCHERS |
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221 | $w = AnyEvent->timer (after => <seconds>, cb => <callback>); |
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222 | |
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223 | $w = AnyEvent->timer ( |
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224 | after => <fractional_seconds>, |
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225 | interval => <fractional_seconds>, |
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226 | cb => <callback>, |
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227 | ); |
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228 | |
208 | You can create a time watcher by calling the "AnyEvent->timer" method |
229 | You can create a time watcher by calling the "AnyEvent->timer" method |
209 | with the following mandatory arguments: |
230 | with the following mandatory arguments: |
210 | |
231 | |
211 | "after" specifies after how many seconds (fractional values are |
232 | "after" specifies after how many seconds (fractional values are |
212 | supported) the callback should be invoked. "cb" is the callback to |
233 | supported) the callback should be invoked. "cb" is the callback to |
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333 | time, which might affect timers and time-outs. |
354 | time, which might affect timers and time-outs. |
334 | |
355 | |
335 | When this is the case, you can call this method, which will update |
356 | When this is the case, you can call this method, which will update |
336 | the event loop's idea of "current time". |
357 | the event loop's idea of "current time". |
337 | |
358 | |
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359 | A typical example would be a script in a web server (e.g. |
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360 | "mod_perl") - when mod_perl executes the script, then the event loop |
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361 | will have the wrong idea about the "current time" (being potentially |
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362 | far in the past, when the script ran the last time). In that case |
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363 | you should arrange a call to "AnyEvent->now_update" each time the |
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364 | web server process wakes up again (e.g. at the start of your script, |
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365 | or in a handler). |
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366 | |
338 | Note that updating the time *might* cause some events to be handled. |
367 | Note that updating the time *might* cause some events to be handled. |
339 | |
368 | |
340 | SIGNAL WATCHERS |
369 | SIGNAL WATCHERS |
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370 | $w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>); |
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371 | |
341 | You can watch for signals using a signal watcher, "signal" is the signal |
372 | You can watch for signals using a signal watcher, "signal" is the signal |
342 | *name* in uppercase and without any "SIG" prefix, "cb" is the Perl |
373 | *name* in uppercase and without any "SIG" prefix, "cb" is the Perl |
343 | callback to be invoked whenever a signal occurs. |
374 | callback to be invoked whenever a signal occurs. |
344 | |
375 | |
345 | Although the callback might get passed parameters, their value and |
376 | Although the callback might get passed parameters, their value and |
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350 | invocation, and callback invocation will be synchronous. Synchronous |
381 | invocation, and callback invocation will be synchronous. Synchronous |
351 | means that it might take a while until the signal gets handled by the |
382 | means that it might take a while until the signal gets handled by the |
352 | process, but it is guaranteed not to interrupt any other callbacks. |
383 | process, but it is guaranteed not to interrupt any other callbacks. |
353 | |
384 | |
354 | The main advantage of using these watchers is that you can share a |
385 | The main advantage of using these watchers is that you can share a |
355 | signal between multiple watchers. |
386 | signal between multiple watchers, and AnyEvent will ensure that signals |
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387 | will not interrupt your program at bad times. |
356 | |
388 | |
357 | This watcher might use %SIG, so programs overwriting those signals |
389 | This watcher might use %SIG (depending on the event loop used), so |
358 | directly will likely not work correctly. |
390 | programs overwriting those signals directly will likely not work |
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391 | correctly. |
359 | |
392 | |
360 | Example: exit on SIGINT |
393 | Example: exit on SIGINT |
361 | |
394 | |
362 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
395 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
363 | |
396 | |
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397 | Restart Behaviour |
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398 | While restart behaviour is up to the event loop implementation, most |
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399 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
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400 | pure perl implementation). |
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401 | |
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402 | Safe/Unsafe Signals |
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403 | Perl signals can be either "safe" (synchronous to opcode handling) or |
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404 | "unsafe" (asynchronous) - the former might get delayed indefinitely, the |
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405 | latter might corrupt your memory. |
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406 | |
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407 | AnyEvent signal handlers are, in addition, synchronous to the event |
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408 | loop, i.e. they will not interrupt your running perl program but will |
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409 | only be called as part of the normal event handling (just like timer, |
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410 | I/O etc. callbacks, too). |
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411 | |
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412 | Signal Races, Delays and Workarounds |
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413 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
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414 | callbacks to signals in a generic way, which is a pity, as you cannot do |
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415 | race-free signal handling in perl, requiring C libraries for this. |
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416 | AnyEvent will try to do it's best, which means in some cases, signals |
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417 | will be delayed. The maximum time a signal might be delayed is specified |
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418 | in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable |
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419 | can be changed only before the first signal watcher is created, and |
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420 | should be left alone otherwise. This variable determines how often |
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421 | AnyEvent polls for signals (in case a wake-up was missed). Higher values |
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422 | will cause fewer spurious wake-ups, which is better for power and CPU |
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423 | saving. |
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424 | |
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425 | All these problems can be avoided by installing the optional |
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426 | Async::Interrupt module, which works with most event loops. It will not |
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427 | work with inherently broken event loops such as Event or Event::Lib (and |
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428 | not with POE currently, as POE does it's own workaround with one-second |
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429 | latency). For those, you just have to suffer the delays. |
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430 | |
364 | CHILD PROCESS WATCHERS |
431 | CHILD PROCESS WATCHERS |
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432 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
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433 | |
365 | You can also watch on a child process exit and catch its exit status. |
434 | You can also watch on a child process exit and catch its exit status. |
366 | |
435 | |
367 | The child process is specified by the "pid" argument (if set to 0, it |
436 | The child process is specified by the "pid" argument (one some backends, |
368 | watches for any child process exit). The watcher will triggered only |
437 | using 0 watches for any child process exit, on others this will croak). |
369 | when the child process has finished and an exit status is available, not |
438 | The watcher will be triggered only when the child process has finished |
370 | on any trace events (stopped/continued). |
439 | and an exit status is available, not on any trace events |
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440 | (stopped/continued). |
371 | |
441 | |
372 | The callback will be called with the pid and exit status (as returned by |
442 | The callback will be called with the pid and exit status (as returned by |
373 | waitpid), so unlike other watcher types, you *can* rely on child watcher |
443 | waitpid), so unlike other watcher types, you *can* rely on child watcher |
374 | callback arguments. |
444 | callback arguments. |
375 | |
445 | |
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390 | of when you start the watcher. |
460 | of when you start the watcher. |
391 | |
461 | |
392 | This means you cannot create a child watcher as the very first thing in |
462 | This means you cannot create a child watcher as the very first thing in |
393 | an AnyEvent program, you *have* to create at least one watcher before |
463 | an AnyEvent program, you *have* to create at least one watcher before |
394 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
464 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
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465 | |
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466 | As most event loops do not support waiting for child events, they will |
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467 | be emulated by AnyEvent in most cases, in which the latency and race |
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468 | problems mentioned in the description of signal watchers apply. |
395 | |
469 | |
396 | Example: fork a process and wait for it |
470 | Example: fork a process and wait for it |
397 | |
471 | |
398 | my $done = AnyEvent->condvar; |
472 | my $done = AnyEvent->condvar; |
399 | |
473 | |
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410 | |
484 | |
411 | # do something else, then wait for process exit |
485 | # do something else, then wait for process exit |
412 | $done->recv; |
486 | $done->recv; |
413 | |
487 | |
414 | IDLE WATCHERS |
488 | IDLE WATCHERS |
415 | Sometimes there is a need to do something, but it is not so important to |
489 | $w = AnyEvent->idle (cb => <callback>); |
416 | do it instantly, but only when there is nothing better to do. This |
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417 | "nothing better to do" is usually defined to be "no other events need |
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418 | attention by the event loop". |
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419 | |
490 | |
420 | Idle watchers ideally get invoked when the event loop has nothing better |
491 | Repeatedly invoke the callback after the process becomes idle, until |
421 | to do, just before it would block the process to wait for new events. |
492 | either the watcher is destroyed or new events have been detected. |
422 | Instead of blocking, the idle watcher is invoked. |
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423 | |
493 | |
424 | Most event loops unfortunately do not really support idle watchers (only |
494 | Idle watchers are useful when there is a need to do something, but it is |
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495 | not so important (or wise) to do it instantly. The callback will be |
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496 | invoked only when there is "nothing better to do", which is usually |
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497 | defined as "all outstanding events have been handled and no new events |
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498 | have been detected". That means that idle watchers ideally get invoked |
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499 | when the event loop has just polled for new events but none have been |
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500 | detected. Instead of blocking to wait for more events, the idle watchers |
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501 | will be invoked. |
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502 | |
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503 | Unfortunately, most event loops do not really support idle watchers |
425 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
504 | (only EV, Event and Glib do it in a usable fashion) - for the rest, |
426 | will simply call the callback "from time to time". |
505 | AnyEvent will simply call the callback "from time to time". |
427 | |
506 | |
428 | Example: read lines from STDIN, but only process them when the program |
507 | Example: read lines from STDIN, but only process them when the program |
429 | is otherwise idle: |
508 | is otherwise idle: |
430 | |
509 | |
431 | my @lines; # read data |
510 | my @lines; # read data |
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444 | } |
523 | } |
445 | }); |
524 | }); |
446 | }); |
525 | }); |
447 | |
526 | |
448 | CONDITION VARIABLES |
527 | CONDITION VARIABLES |
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528 | $cv = AnyEvent->condvar; |
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529 | |
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530 | $cv->send (<list>); |
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531 | my @res = $cv->recv; |
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532 | |
449 | If you are familiar with some event loops you will know that all of them |
533 | If you are familiar with some event loops you will know that all of them |
450 | require you to run some blocking "loop", "run" or similar function that |
534 | require you to run some blocking "loop", "run" or similar function that |
451 | will actively watch for new events and call your callbacks. |
535 | will actively watch for new events and call your callbacks. |
452 | |
536 | |
453 | AnyEvent is different, it expects somebody else to run the event loop |
537 | AnyEvent is slightly different: it expects somebody else to run the |
454 | and will only block when necessary (usually when told by the user). |
538 | event loop and will only block when necessary (usually when told by the |
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539 | user). |
455 | |
540 | |
456 | The instrument to do that is called a "condition variable", so called |
541 | The instrument to do that is called a "condition variable", so called |
457 | because they represent a condition that must become true. |
542 | because they represent a condition that must become true. |
458 | |
543 | |
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544 | Now is probably a good time to look at the examples further below. |
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545 | |
459 | Condition variables can be created by calling the "AnyEvent->condvar" |
546 | Condition variables can be created by calling the "AnyEvent->condvar" |
460 | method, usually without arguments. The only argument pair allowed is |
547 | method, usually without arguments. The only argument pair allowed is |
461 | |
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462 | "cb", which specifies a callback to be called when the condition |
548 | "cb", which specifies a callback to be called when the condition |
463 | variable becomes true, with the condition variable as the first argument |
549 | variable becomes true, with the condition variable as the first argument |
464 | (but not the results). |
550 | (but not the results). |
465 | |
551 | |
466 | After creation, the condition variable is "false" until it becomes |
552 | After creation, the condition variable is "false" until it becomes |
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471 | Condition variables are similar to callbacks, except that you can |
557 | Condition variables are similar to callbacks, except that you can |
472 | optionally wait for them. They can also be called merge points - points |
558 | optionally wait for them. They can also be called merge points - points |
473 | in time where multiple outstanding events have been processed. And yet |
559 | in time where multiple outstanding events have been processed. And yet |
474 | another way to call them is transactions - each condition variable can |
560 | another way to call them is transactions - each condition variable can |
475 | be used to represent a transaction, which finishes at some point and |
561 | be used to represent a transaction, which finishes at some point and |
476 | delivers a result. |
562 | delivers a result. And yet some people know them as "futures" - a |
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563 | promise to compute/deliver something that you can wait for. |
477 | |
564 | |
478 | Condition variables are very useful to signal that something has |
565 | Condition variables are very useful to signal that something has |
479 | finished, for example, if you write a module that does asynchronous http |
566 | finished, for example, if you write a module that does asynchronous http |
480 | requests, then a condition variable would be the ideal candidate to |
567 | requests, then a condition variable would be the ideal candidate to |
481 | signal the availability of results. The user can either act when the |
568 | signal the availability of results. The user can either act when the |
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515 | after => 1, |
602 | after => 1, |
516 | cb => sub { $result_ready->send }, |
603 | cb => sub { $result_ready->send }, |
517 | ); |
604 | ); |
518 | |
605 | |
519 | # this "blocks" (while handling events) till the callback |
606 | # this "blocks" (while handling events) till the callback |
520 | # calls send |
607 | # calls ->send |
521 | $result_ready->recv; |
608 | $result_ready->recv; |
522 | |
609 | |
523 | Example: wait for a timer, but take advantage of the fact that condition |
610 | Example: wait for a timer, but take advantage of the fact that condition |
524 | variables are also code references. |
611 | variables are also callable directly. |
525 | |
612 | |
526 | my $done = AnyEvent->condvar; |
613 | my $done = AnyEvent->condvar; |
527 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
614 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
528 | $done->recv; |
615 | $done->recv; |
529 | |
616 | |
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535 | |
622 | |
536 | ... |
623 | ... |
537 | |
624 | |
538 | my @info = $couchdb->info->recv; |
625 | my @info = $couchdb->info->recv; |
539 | |
626 | |
540 | And this is how you would just ste a callback to be called whenever the |
627 | And this is how you would just set a callback to be called whenever the |
541 | results are available: |
628 | results are available: |
542 | |
629 | |
543 | $couchdb->info->cb (sub { |
630 | $couchdb->info->cb (sub { |
544 | my @info = $_[0]->recv; |
631 | my @info = $_[0]->recv; |
545 | }); |
632 | }); |
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560 | |
647 | |
561 | Any arguments passed to the "send" call will be returned by all |
648 | Any arguments passed to the "send" call will be returned by all |
562 | future "->recv" calls. |
649 | future "->recv" calls. |
563 | |
650 | |
564 | Condition variables are overloaded so one can call them directly (as |
651 | Condition variables are overloaded so one can call them directly (as |
565 | a code reference). Calling them directly is the same as calling |
652 | if they were a code reference). Calling them directly is the same as |
566 | "send". Note, however, that many C-based event loops do not handle |
653 | calling "send". |
567 | overloading, so as tempting as it may be, passing a condition |
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568 | variable instead of a callback does not work. Both the pure perl and |
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569 | EV loops support overloading, however, as well as all functions that |
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570 | use perl to invoke a callback (as in AnyEvent::Socket and |
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571 | AnyEvent::DNS for example). |
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572 | |
654 | |
573 | $cv->croak ($error) |
655 | $cv->croak ($error) |
574 | Similar to send, but causes all call's to "->recv" to invoke |
656 | Similar to send, but causes all call's to "->recv" to invoke |
575 | "Carp::croak" with the given error message/object/scalar. |
657 | "Carp::croak" with the given error message/object/scalar. |
576 | |
658 | |
577 | This can be used to signal any errors to the condition variable |
659 | This can be used to signal any errors to the condition variable |
578 | user/consumer. |
660 | user/consumer. Doing it this way instead of calling "croak" directly |
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661 | delays the error detetcion, but has the overwhelmign advantage that |
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662 | it diagnoses the error at the place where the result is expected, |
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663 | and not deep in some event clalback without connection to the actual |
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664 | code causing the problem. |
579 | |
665 | |
580 | $cv->begin ([group callback]) |
666 | $cv->begin ([group callback]) |
581 | $cv->end |
667 | $cv->end |
582 | These two methods can be used to combine many transactions/events |
668 | These two methods can be used to combine many transactions/events |
583 | into one. For example, a function that pings many hosts in parallel |
669 | into one. For example, a function that pings many hosts in parallel |
584 | might want to use a condition variable for the whole process. |
670 | might want to use a condition variable for the whole process. |
585 | |
671 | |
586 | Every call to "->begin" will increment a counter, and every call to |
672 | Every call to "->begin" will increment a counter, and every call to |
587 | "->end" will decrement it. If the counter reaches 0 in "->end", the |
673 | "->end" will decrement it. If the counter reaches 0 in "->end", the |
588 | (last) callback passed to "begin" will be executed. That callback is |
674 | (last) callback passed to "begin" will be executed, passing the |
589 | *supposed* to call "->send", but that is not required. If no |
675 | condvar as first argument. That callback is *supposed* to call |
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676 | "->send", but that is not required. If no group callback was set, |
590 | callback was set, "send" will be called without any arguments. |
677 | "send" will be called without any arguments. |
591 | |
678 | |
592 | You can think of "$cv->send" giving you an OR condition (one call |
679 | You can think of "$cv->send" giving you an OR condition (one call |
593 | sends), while "$cv->begin" and "$cv->end" giving you an AND |
680 | sends), while "$cv->begin" and "$cv->end" giving you an AND |
594 | condition (all "begin" calls must be "end"'ed before the condvar |
681 | condition (all "begin" calls must be "end"'ed before the condvar |
595 | sends). |
682 | sends). |
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623 | that are begung can potentially be zero: |
710 | that are begung can potentially be zero: |
624 | |
711 | |
625 | my $cv = AnyEvent->condvar; |
712 | my $cv = AnyEvent->condvar; |
626 | |
713 | |
627 | my %result; |
714 | my %result; |
628 | $cv->begin (sub { $cv->send (\%result) }); |
715 | $cv->begin (sub { shift->send (\%result) }); |
629 | |
716 | |
630 | for my $host (@list_of_hosts) { |
717 | for my $host (@list_of_hosts) { |
631 | $cv->begin; |
718 | $cv->begin; |
632 | ping_host_then_call_callback $host, sub { |
719 | ping_host_then_call_callback $host, sub { |
633 | $result{$host} = ...; |
720 | $result{$host} = ...; |
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671 | function will call "croak". |
758 | function will call "croak". |
672 | |
759 | |
673 | In list context, all parameters passed to "send" will be returned, |
760 | In list context, all parameters passed to "send" will be returned, |
674 | in scalar context only the first one will be returned. |
761 | in scalar context only the first one will be returned. |
675 | |
762 | |
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763 | Note that doing a blocking wait in a callback is not supported by |
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|
764 | any event loop, that is, recursive invocation of a blocking "->recv" |
|
|
765 | is not allowed, and the "recv" call will "croak" if such a condition |
|
|
766 | is detected. This condition can be slightly loosened by using |
|
|
767 | Coro::AnyEvent, which allows you to do a blocking "->recv" from any |
|
|
768 | thread that doesn't run the event loop itself. |
|
|
769 | |
676 | Not all event models support a blocking wait - some die in that case |
770 | Not all event models support a blocking wait - some die in that case |
677 | (programs might want to do that to stay interactive), so *if you are |
771 | (programs might want to do that to stay interactive), so *if you are |
678 | using this from a module, never require a blocking wait*, but let |
772 | using this from a module, never require a blocking wait*. Instead, |
679 | the caller decide whether the call will block or not (for example, |
773 | let the caller decide whether the call will block or not (for |
680 | by coupling condition variables with some kind of request results |
774 | example, by coupling condition variables with some kind of request |
681 | and supporting callbacks so the caller knows that getting the result |
775 | results and supporting callbacks so the caller knows that getting |
682 | will not block, while still supporting blocking waits if the caller |
776 | the result will not block, while still supporting blocking waits if |
683 | so desires). |
777 | the caller so desires). |
684 | |
|
|
685 | Another reason *never* to "->recv" in a module is that you cannot |
|
|
686 | sensibly have two "->recv"'s in parallel, as that would require |
|
|
687 | multiple interpreters or coroutines/threads, none of which |
|
|
688 | "AnyEvent" can supply. |
|
|
689 | |
|
|
690 | The Coro module, however, *can* and *does* supply coroutines and, in |
|
|
691 | fact, Coro::AnyEvent replaces AnyEvent's condvars by coroutine-safe |
|
|
692 | versions and also integrates coroutines into AnyEvent, making |
|
|
693 | blocking "->recv" calls perfectly safe as long as they are done from |
|
|
694 | another coroutine (one that doesn't run the event loop). |
|
|
695 | |
778 | |
696 | You can ensure that "-recv" never blocks by setting a callback and |
779 | You can ensure that "-recv" never blocks by setting a callback and |
697 | only calling "->recv" from within that callback (or at a later |
780 | only calling "->recv" from within that callback (or at a later |
698 | time). This will work even when the event loop does not support |
781 | time). This will work even when the event loop does not support |
699 | blocking waits otherwise. |
782 | blocking waits otherwise. |
… | |
… | |
704 | |
787 | |
705 | $cb = $cv->cb ($cb->($cv)) |
788 | $cb = $cv->cb ($cb->($cv)) |
706 | This is a mutator function that returns the callback set and |
789 | This is a mutator function that returns the callback set and |
707 | optionally replaces it before doing so. |
790 | optionally replaces it before doing so. |
708 | |
791 | |
709 | The callback will be called when the condition becomes "true", i.e. |
792 | The callback will be called when the condition becomes (or already |
710 | when "send" or "croak" are called, with the only argument being the |
793 | was) "true", i.e. when "send" or "croak" are called (or were |
711 | condition variable itself. Calling "recv" inside the callback or at |
794 | called), with the only argument being the condition variable itself. |
|
|
795 | Calling "recv" inside the callback or at any later time is |
712 | any later time is guaranteed not to block. |
796 | guaranteed not to block. |
|
|
797 | |
|
|
798 | SUPPORTED EVENT LOOPS/BACKENDS |
|
|
799 | The available backend classes are (every class has its own manpage): |
|
|
800 | |
|
|
801 | Backends that are autoprobed when no other event loop can be found. |
|
|
802 | EV is the preferred backend when no other event loop seems to be in |
|
|
803 | use. If EV is not installed, then AnyEvent will fall back to its own |
|
|
804 | pure-perl implementation, which is available everywhere as it comes |
|
|
805 | with AnyEvent itself. |
|
|
806 | |
|
|
807 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
|
|
808 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
|
|
809 | |
|
|
810 | Backends that are transparently being picked up when they are used. |
|
|
811 | These will be used when they are currently loaded when the first |
|
|
812 | watcher is created, in which case it is assumed that the application |
|
|
813 | is using them. This means that AnyEvent will automatically pick the |
|
|
814 | right backend when the main program loads an event module before |
|
|
815 | anything starts to create watchers. Nothing special needs to be done |
|
|
816 | by the main program. |
|
|
817 | |
|
|
818 | AnyEvent::Impl::Event based on Event, very stable, few glitches. |
|
|
819 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
|
|
820 | AnyEvent::Impl::Tk based on Tk, very broken. |
|
|
821 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
|
|
822 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
|
|
823 | AnyEvent::Impl::Irssi used when running within irssi. |
|
|
824 | |
|
|
825 | Backends with special needs. |
|
|
826 | Qt requires the Qt::Application to be instantiated first, but will |
|
|
827 | otherwise be picked up automatically. As long as the main program |
|
|
828 | instantiates the application before any AnyEvent watchers are |
|
|
829 | created, everything should just work. |
|
|
830 | |
|
|
831 | AnyEvent::Impl::Qt based on Qt. |
|
|
832 | |
|
|
833 | Support for IO::Async can only be partial, as it is too broken and |
|
|
834 | architecturally limited to even support the AnyEvent API. It also is |
|
|
835 | the only event loop that needs the loop to be set explicitly, so it |
|
|
836 | can only be used by a main program knowing about AnyEvent. See |
|
|
837 | AnyEvent::Impl::Async for the gory details. |
|
|
838 | |
|
|
839 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed. |
|
|
840 | |
|
|
841 | Event loops that are indirectly supported via other backends. |
|
|
842 | Some event loops can be supported via other modules: |
|
|
843 | |
|
|
844 | There is no direct support for WxWidgets (Wx) or Prima. |
|
|
845 | |
|
|
846 | WxWidgets has no support for watching file handles. However, you can |
|
|
847 | use WxWidgets through the POE adaptor, as POE has a Wx backend that |
|
|
848 | simply polls 20 times per second, which was considered to be too |
|
|
849 | horrible to even consider for AnyEvent. |
|
|
850 | |
|
|
851 | Prima is not supported as nobody seems to be using it, but it has a |
|
|
852 | POE backend, so it can be supported through POE. |
|
|
853 | |
|
|
854 | AnyEvent knows about both Prima and Wx, however, and will try to |
|
|
855 | load POE when detecting them, in the hope that POE will pick them |
|
|
856 | up, in which case everything will be automatic. |
713 | |
857 | |
714 | GLOBAL VARIABLES AND FUNCTIONS |
858 | GLOBAL VARIABLES AND FUNCTIONS |
|
|
859 | These are not normally required to use AnyEvent, but can be useful to |
|
|
860 | write AnyEvent extension modules. |
|
|
861 | |
715 | $AnyEvent::MODEL |
862 | $AnyEvent::MODEL |
716 | Contains "undef" until the first watcher is being created. Then it |
863 | Contains "undef" until the first watcher is being created, before |
|
|
864 | the backend has been autodetected. |
|
|
865 | |
717 | contains the event model that is being used, which is the name of |
866 | Afterwards it contains the event model that is being used, which is |
718 | the Perl class implementing the model. This class is usually one of |
867 | the name of the Perl class implementing the model. This class is |
719 | the "AnyEvent::Impl:xxx" modules, but can be any other class in the |
868 | usually one of the "AnyEvent::Impl:xxx" modules, but can be any |
720 | case AnyEvent has been extended at runtime (e.g. in *rxvt-unicode*). |
869 | other class in the case AnyEvent has been extended at runtime (e.g. |
721 | |
870 | in *rxvt-unicode* it will be "urxvt::anyevent"). |
722 | The known classes so far are: |
|
|
723 | |
|
|
724 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
|
|
725 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
726 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
|
|
727 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
|
|
728 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
|
|
729 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
|
|
730 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
|
|
731 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
|
|
732 | |
|
|
733 | # warning, support for IO::Async is only partial, as it is too broken |
|
|
734 | # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async. |
|
|
735 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs). |
|
|
736 | |
|
|
737 | There is no support for WxWidgets, as WxWidgets has no support for |
|
|
738 | watching file handles. However, you can use WxWidgets through the |
|
|
739 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
|
|
740 | second, which was considered to be too horrible to even consider for |
|
|
741 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by |
|
|
742 | using it's adaptor. |
|
|
743 | |
|
|
744 | AnyEvent knows about Prima and Wx and will try to use POE when |
|
|
745 | autodetecting them. |
|
|
746 | |
871 | |
747 | AnyEvent::detect |
872 | AnyEvent::detect |
748 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
873 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
749 | if necessary. You should only call this function right before you |
874 | if necessary. You should only call this function right before you |
750 | would have created an AnyEvent watcher anyway, that is, as late as |
875 | would have created an AnyEvent watcher anyway, that is, as late as |
751 | possible at runtime. |
876 | possible at runtime, and not e.g. while initialising of your module. |
|
|
877 | |
|
|
878 | If you need to do some initialisation before AnyEvent watchers are |
|
|
879 | created, use "post_detect". |
752 | |
880 | |
753 | $guard = AnyEvent::post_detect { BLOCK } |
881 | $guard = AnyEvent::post_detect { BLOCK } |
754 | Arranges for the code block to be executed as soon as the event |
882 | Arranges for the code block to be executed as soon as the event |
755 | model is autodetected (or immediately if this has already happened). |
883 | model is autodetected (or immediately if this has already happened). |
756 | |
884 | |
|
|
885 | The block will be executed *after* the actual backend has been |
|
|
886 | detected ($AnyEvent::MODEL is set), but *before* any watchers have |
|
|
887 | been created, so it is possible to e.g. patch @AnyEvent::ISA or do |
|
|
888 | other initialisations - see the sources of AnyEvent::Strict or |
|
|
889 | AnyEvent::AIO to see how this is used. |
|
|
890 | |
|
|
891 | The most common usage is to create some global watchers, without |
|
|
892 | forcing event module detection too early, for example, AnyEvent::AIO |
|
|
893 | creates and installs the global IO::AIO watcher in a "post_detect" |
|
|
894 | block to avoid autodetecting the event module at load time. |
|
|
895 | |
757 | If called in scalar or list context, then it creates and returns an |
896 | If called in scalar or list context, then it creates and returns an |
758 | object that automatically removes the callback again when it is |
897 | object that automatically removes the callback again when it is |
|
|
898 | destroyed (or "undef" when the hook was immediately executed). See |
759 | destroyed. See Coro::BDB for a case where this is useful. |
899 | AnyEvent::AIO for a case where this is useful. |
|
|
900 | |
|
|
901 | Example: Create a watcher for the IO::AIO module and store it in |
|
|
902 | $WATCHER. Only do so after the event loop is initialised, though. |
|
|
903 | |
|
|
904 | our WATCHER; |
|
|
905 | |
|
|
906 | my $guard = AnyEvent::post_detect { |
|
|
907 | $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); |
|
|
908 | }; |
|
|
909 | |
|
|
910 | # the ||= is important in case post_detect immediately runs the block, |
|
|
911 | # as to not clobber the newly-created watcher. assigning both watcher and |
|
|
912 | # post_detect guard to the same variable has the advantage of users being |
|
|
913 | # able to just C<undef $WATCHER> if the watcher causes them grief. |
|
|
914 | |
|
|
915 | $WATCHER ||= $guard; |
760 | |
916 | |
761 | @AnyEvent::post_detect |
917 | @AnyEvent::post_detect |
762 | If there are any code references in this array (you can "push" to it |
918 | If there are any code references in this array (you can "push" to it |
763 | before or after loading AnyEvent), then they will called directly |
919 | before or after loading AnyEvent), then they will called directly |
764 | after the event loop has been chosen. |
920 | after the event loop has been chosen. |
765 | |
921 | |
766 | You should check $AnyEvent::MODEL before adding to this array, |
922 | You should check $AnyEvent::MODEL before adding to this array, |
767 | though: if it contains a true value then the event loop has already |
923 | though: if it is defined then the event loop has already been |
768 | been detected, and the array will be ignored. |
924 | detected, and the array will be ignored. |
769 | |
925 | |
770 | Best use "AnyEvent::post_detect { BLOCK }" instead. |
926 | Best use "AnyEvent::post_detect { BLOCK }" when your application |
|
|
927 | allows it, as it takes care of these details. |
|
|
928 | |
|
|
929 | This variable is mainly useful for modules that can do something |
|
|
930 | useful when AnyEvent is used and thus want to know when it is |
|
|
931 | initialised, but do not need to even load it by default. This array |
|
|
932 | provides the means to hook into AnyEvent passively, without loading |
|
|
933 | it. |
|
|
934 | |
|
|
935 | Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used |
|
|
936 | together, you could put this into Coro (this is the actual code used |
|
|
937 | by Coro to accomplish this): |
|
|
938 | |
|
|
939 | if (defined $AnyEvent::MODEL) { |
|
|
940 | # AnyEvent already initialised, so load Coro::AnyEvent |
|
|
941 | require Coro::AnyEvent; |
|
|
942 | } else { |
|
|
943 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
|
|
944 | # as soon as it is |
|
|
945 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
|
|
946 | } |
771 | |
947 | |
772 | WHAT TO DO IN A MODULE |
948 | WHAT TO DO IN A MODULE |
773 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
949 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
774 | freely, but you should not load a specific event module or rely on it. |
950 | freely, but you should not load a specific event module or rely on it. |
775 | |
951 | |
… | |
… | |
826 | variable somewhere, waiting for it, and sending it when the program |
1002 | variable somewhere, waiting for it, and sending it when the program |
827 | should exit cleanly. |
1003 | should exit cleanly. |
828 | |
1004 | |
829 | OTHER MODULES |
1005 | OTHER MODULES |
830 | The following is a non-exhaustive list of additional modules that use |
1006 | The following is a non-exhaustive list of additional modules that use |
831 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
1007 | AnyEvent as a client and can therefore be mixed easily with other |
832 | in the same program. Some of the modules come with AnyEvent, some are |
1008 | AnyEvent modules and other event loops in the same program. Some of the |
833 | available via CPAN. |
1009 | modules come with AnyEvent, most are available via CPAN. |
834 | |
1010 | |
835 | AnyEvent::Util |
1011 | AnyEvent::Util |
836 | Contains various utility functions that replace often-used but |
1012 | Contains various utility functions that replace often-used but |
837 | blocking functions such as "inet_aton" by event-/callback-based |
1013 | blocking functions such as "inet_aton" by event-/callback-based |
838 | versions. |
1014 | versions. |
… | |
… | |
844 | more. |
1020 | more. |
845 | |
1021 | |
846 | AnyEvent::Handle |
1022 | AnyEvent::Handle |
847 | Provide read and write buffers, manages watchers for reads and |
1023 | Provide read and write buffers, manages watchers for reads and |
848 | writes, supports raw and formatted I/O, I/O queued and fully |
1024 | writes, supports raw and formatted I/O, I/O queued and fully |
849 | transparent and non-blocking SSL/TLS. |
1025 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS. |
850 | |
1026 | |
851 | AnyEvent::DNS |
1027 | AnyEvent::DNS |
852 | Provides rich asynchronous DNS resolver capabilities. |
1028 | Provides rich asynchronous DNS resolver capabilities. |
853 | |
1029 | |
854 | AnyEvent::HTTP |
1030 | AnyEvent::HTTP |
… | |
… | |
875 | |
1051 | |
876 | AnyEvent::GPSD |
1052 | AnyEvent::GPSD |
877 | A non-blocking interface to gpsd, a daemon delivering GPS |
1053 | A non-blocking interface to gpsd, a daemon delivering GPS |
878 | information. |
1054 | information. |
879 | |
1055 | |
|
|
1056 | AnyEvent::IRC |
|
|
1057 | AnyEvent based IRC client module family (replacing the older |
|
|
1058 | Net::IRC3). |
|
|
1059 | |
|
|
1060 | AnyEvent::XMPP |
|
|
1061 | AnyEvent based XMPP (Jabber protocol) module family (replacing the |
|
|
1062 | older Net::XMPP2>. |
|
|
1063 | |
880 | AnyEvent::IGS |
1064 | AnyEvent::IGS |
881 | A non-blocking interface to the Internet Go Server protocol (used by |
1065 | A non-blocking interface to the Internet Go Server protocol (used by |
882 | App::IGS). |
1066 | App::IGS). |
883 | |
1067 | |
884 | AnyEvent::IRC |
|
|
885 | AnyEvent based IRC client module family (replacing the older |
|
|
886 | Net::IRC3). |
|
|
887 | |
|
|
888 | Net::XMPP2 |
|
|
889 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
890 | |
|
|
891 | Net::FCP |
1068 | Net::FCP |
892 | AnyEvent-based implementation of the Freenet Client Protocol, |
1069 | AnyEvent-based implementation of the Freenet Client Protocol, |
893 | birthplace of AnyEvent. |
1070 | birthplace of AnyEvent. |
894 | |
1071 | |
895 | Event::ExecFlow |
1072 | Event::ExecFlow |
896 | High level API for event-based execution flow control. |
1073 | High level API for event-based execution flow control. |
897 | |
1074 | |
898 | Coro |
1075 | Coro |
899 | Has special support for AnyEvent via Coro::AnyEvent. |
1076 | Has special support for AnyEvent via Coro::AnyEvent. |
900 | |
1077 | |
901 | IO::Lambda |
1078 | SIMPLIFIED AE API |
902 | The lambda approach to I/O - don't ask, look there. Can use |
1079 | Starting with version 5.0, AnyEvent officially supports a second, much |
903 | AnyEvent. |
1080 | simpler, API that is designed to reduce the calling, typing and memory |
|
|
1081 | overhead. |
|
|
1082 | |
|
|
1083 | See the AE manpage for details. |
904 | |
1084 | |
905 | ERROR AND EXCEPTION HANDLING |
1085 | ERROR AND EXCEPTION HANDLING |
906 | In general, AnyEvent does not do any error handling - it relies on the |
1086 | In general, AnyEvent does not do any error handling - it relies on the |
907 | caller to do that if required. The AnyEvent::Strict module (see also the |
1087 | caller to do that if required. The AnyEvent::Strict module (see also the |
908 | "PERL_ANYEVENT_STRICT" environment variable, below) provides strict |
1088 | "PERL_ANYEVENT_STRICT" environment variable, below) provides strict |
… | |
… | |
936 | by "PERL_ANYEVENT_MODEL". |
1116 | by "PERL_ANYEVENT_MODEL". |
937 | |
1117 | |
938 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
1118 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
939 | event model it chooses. |
1119 | event model it chooses. |
940 | |
1120 | |
|
|
1121 | When set to 8 or higher, then AnyEvent will report extra information |
|
|
1122 | on which optional modules it loads and how it implements certain |
|
|
1123 | features. |
|
|
1124 | |
941 | "PERL_ANYEVENT_STRICT" |
1125 | "PERL_ANYEVENT_STRICT" |
942 | AnyEvent does not do much argument checking by default, as thorough |
1126 | AnyEvent does not do much argument checking by default, as thorough |
943 | argument checking is very costly. Setting this variable to a true |
1127 | argument checking is very costly. Setting this variable to a true |
944 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1128 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
945 | thoroughly check the arguments passed to most method calls. If it |
1129 | thoroughly check the arguments passed to most method calls. If it |
946 | finds any problems, it will croak. |
1130 | finds any problems, it will croak. |
947 | |
1131 | |
948 | In other words, enables "strict" mode. |
1132 | In other words, enables "strict" mode. |
949 | |
1133 | |
950 | Unlike "use strict", it is definitely recommended to keep it off in |
1134 | Unlike "use strict" (or it's modern cousin, "use common::sense", it |
951 | production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment |
1135 | is definitely recommended to keep it off in production. Keeping |
|
|
1136 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
952 | while developing programs can be very useful, however. |
1137 | programs can be very useful, however. |
953 | |
1138 | |
954 | "PERL_ANYEVENT_MODEL" |
1139 | "PERL_ANYEVENT_MODEL" |
955 | This can be used to specify the event model to be used by AnyEvent, |
1140 | This can be used to specify the event model to be used by AnyEvent, |
956 | before auto detection and -probing kicks in. It must be a string |
1141 | before auto detection and -probing kicks in. It must be a string |
957 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
1142 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
… | |
… | |
998 | EDNS0 in its DNS requests. |
1183 | EDNS0 in its DNS requests. |
999 | |
1184 | |
1000 | "PERL_ANYEVENT_MAX_FORKS" |
1185 | "PERL_ANYEVENT_MAX_FORKS" |
1001 | The maximum number of child processes that |
1186 | The maximum number of child processes that |
1002 | "AnyEvent::Util::fork_call" will create in parallel. |
1187 | "AnyEvent::Util::fork_call" will create in parallel. |
|
|
1188 | |
|
|
1189 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
|
|
1190 | The default value for the "max_outstanding" parameter for the |
|
|
1191 | default DNS resolver - this is the maximum number of parallel DNS |
|
|
1192 | requests that are sent to the DNS server. |
|
|
1193 | |
|
|
1194 | "PERL_ANYEVENT_RESOLV_CONF" |
|
|
1195 | The file to use instead of /etc/resolv.conf (or OS-specific |
|
|
1196 | configuration) in the default resolver. When set to the empty |
|
|
1197 | string, no default config will be used. |
|
|
1198 | |
|
|
1199 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
|
|
1200 | When neither "ca_file" nor "ca_path" was specified during |
|
|
1201 | AnyEvent::TLS context creation, and either of these environment |
|
|
1202 | variables exist, they will be used to specify CA certificate |
|
|
1203 | locations instead of a system-dependent default. |
|
|
1204 | |
|
|
1205 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
|
|
1206 | When these are set to 1, then the respective modules are not loaded. |
|
|
1207 | Mostly good for testing AnyEvent itself. |
1003 | |
1208 | |
1004 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1209 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1005 | This is an advanced topic that you do not normally need to use AnyEvent |
1210 | This is an advanced topic that you do not normally need to use AnyEvent |
1006 | in a module. This section is only of use to event loop authors who want |
1211 | in a module. This section is only of use to event loop authors who want |
1007 | to provide AnyEvent compatibility. |
1212 | to provide AnyEvent compatibility. |
… | |
… | |
1062 | warn "read: $input\n"; # output what has been read |
1267 | warn "read: $input\n"; # output what has been read |
1063 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
1268 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
1064 | }, |
1269 | }, |
1065 | ); |
1270 | ); |
1066 | |
1271 | |
1067 | my $time_watcher; # can only be used once |
|
|
1068 | |
|
|
1069 | sub new_timer { |
|
|
1070 | $timer = AnyEvent->timer (after => 1, cb => sub { |
1272 | my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub { |
1071 | warn "timeout\n"; # print 'timeout' about every second |
1273 | warn "timeout\n"; # print 'timeout' at most every second |
1072 | &new_timer; # and restart the time |
|
|
1073 | }); |
|
|
1074 | } |
1274 | }); |
1075 | |
|
|
1076 | new_timer; # create first timer |
|
|
1077 | |
1275 | |
1078 | $cv->recv; # wait until user enters /^q/i |
1276 | $cv->recv; # wait until user enters /^q/i |
1079 | |
1277 | |
1080 | REAL-WORLD EXAMPLE |
1278 | REAL-WORLD EXAMPLE |
1081 | Consider the Net::FCP module. It features (among others) the following |
1279 | Consider the Net::FCP module. It features (among others) the following |
… | |
… | |
1208 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
1406 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
1209 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1407 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1210 | which it is), lets them fire exactly once and destroys them again. |
1408 | which it is), lets them fire exactly once and destroys them again. |
1211 | |
1409 | |
1212 | Source code for this benchmark is found as eg/bench in the AnyEvent |
1410 | Source code for this benchmark is found as eg/bench in the AnyEvent |
1213 | distribution. |
1411 | distribution. It uses the AE interface, which makes a real difference |
|
|
1412 | for the EV and Perl backends only. |
1214 | |
1413 | |
1215 | Explanation of the columns |
1414 | Explanation of the columns |
1216 | *watcher* is the number of event watchers created/destroyed. Since |
1415 | *watcher* is the number of event watchers created/destroyed. Since |
1217 | different event models feature vastly different performances, each event |
1416 | different event models feature vastly different performances, each event |
1218 | loop was given a number of watchers so that overall runtime is |
1417 | loop was given a number of watchers so that overall runtime is |
… | |
… | |
1237 | *destroy* is the time, in microseconds, that it takes to destroy a |
1436 | *destroy* is the time, in microseconds, that it takes to destroy a |
1238 | single watcher. |
1437 | single watcher. |
1239 | |
1438 | |
1240 | Results |
1439 | Results |
1241 | name watchers bytes create invoke destroy comment |
1440 | name watchers bytes create invoke destroy comment |
1242 | EV/EV 400000 224 0.47 0.35 0.27 EV native interface |
1441 | EV/EV 100000 223 0.47 0.43 0.27 EV native interface |
1243 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
1442 | EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers |
1244 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
1443 | Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal |
1245 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
1444 | Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation |
1246 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
1445 | Event/Event 16000 516 31.16 31.84 0.82 Event native interface |
1247 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
1446 | Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers |
1248 | IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll |
1447 | IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll |
1249 | IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll |
1448 | IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll |
1250 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
1449 | Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour |
1251 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
1450 | Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers |
1252 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
1451 | POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event |
1253 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
1452 | POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select |
1254 | |
1453 | |
1255 | Discussion |
1454 | Discussion |
1256 | The benchmark does *not* measure scalability of the event loop very |
1455 | The benchmark does *not* measure scalability of the event loop very |
1257 | well. For example, a select-based event loop (such as the pure perl one) |
1456 | well. For example, a select-based event loop (such as the pure perl one) |
1258 | can never compete with an event loop that uses epoll when the number of |
1457 | can never compete with an event loop that uses epoll when the number of |
… | |
… | |
1269 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
1468 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
1270 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 |
1469 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 |
1271 | CPU cycles with POE. |
1470 | CPU cycles with POE. |
1272 | |
1471 | |
1273 | "EV" is the sole leader regarding speed and memory use, which are both |
1472 | "EV" is the sole leader regarding speed and memory use, which are both |
1274 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
1473 | maximal/minimal, respectively. When using the AE API there is zero |
|
|
1474 | overhead (when going through the AnyEvent API create is about 5-6 times |
|
|
1475 | slower, with other times being equal, so still uses far less memory than |
1275 | far less memory than any other event loop and is still faster than Event |
1476 | any other event loop and is still faster than Event natively). |
1276 | natively. |
|
|
1277 | |
1477 | |
1278 | The pure perl implementation is hit in a few sweet spots (both the |
1478 | The pure perl implementation is hit in a few sweet spots (both the |
1279 | constant timeout and the use of a single fd hit optimisations in the |
1479 | constant timeout and the use of a single fd hit optimisations in the |
1280 | perl interpreter and the backend itself). Nevertheless this shows that |
1480 | perl interpreter and the backend itself). Nevertheless this shows that |
1281 | it adds very little overhead in itself. Like any select-based backend |
1481 | it adds very little overhead in itself. Like any select-based backend |
… | |
… | |
1351 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which |
1551 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which |
1352 | 100 (1%) are active. This mirrors the activity of large servers with |
1552 | 100 (1%) are active. This mirrors the activity of large servers with |
1353 | many connections, most of which are idle at any one point in time. |
1553 | many connections, most of which are idle at any one point in time. |
1354 | |
1554 | |
1355 | Source code for this benchmark is found as eg/bench2 in the AnyEvent |
1555 | Source code for this benchmark is found as eg/bench2 in the AnyEvent |
1356 | distribution. |
1556 | distribution. It uses the AE interface, which makes a real difference |
|
|
1557 | for the EV and Perl backends only. |
1357 | |
1558 | |
1358 | Explanation of the columns |
1559 | Explanation of the columns |
1359 | *sockets* is the number of sockets, and twice the number of "servers" |
1560 | *sockets* is the number of sockets, and twice the number of "servers" |
1360 | (as each server has a read and write socket end). |
1561 | (as each server has a read and write socket end). |
1361 | |
1562 | |
… | |
… | |
1367 | forwarding it to another server. This includes deleting the old timeout |
1568 | forwarding it to another server. This includes deleting the old timeout |
1368 | and creating a new one that moves the timeout into the future. |
1569 | and creating a new one that moves the timeout into the future. |
1369 | |
1570 | |
1370 | Results |
1571 | Results |
1371 | name sockets create request |
1572 | name sockets create request |
1372 | EV 20000 69.01 11.16 |
1573 | EV 20000 62.66 7.99 |
1373 | Perl 20000 73.32 35.87 |
1574 | Perl 20000 68.32 32.64 |
1374 | IOAsync 20000 157.00 98.14 epoll |
1575 | IOAsync 20000 174.06 101.15 epoll |
1375 | IOAsync 20000 159.31 616.06 poll |
1576 | IOAsync 20000 174.67 610.84 poll |
1376 | Event 20000 212.62 257.32 |
1577 | Event 20000 202.69 242.91 |
1377 | Glib 20000 651.16 1896.30 |
1578 | Glib 20000 557.01 1689.52 |
1378 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1579 | POE 20000 341.54 12086.32 uses POE::Loop::Event |
1379 | |
1580 | |
1380 | Discussion |
1581 | Discussion |
1381 | This benchmark *does* measure scalability and overall performance of the |
1582 | This benchmark *does* measure scalability and overall performance of the |
1382 | particular event loop. |
1583 | particular event loop. |
1383 | |
1584 | |
… | |
… | |
1496 | As you can see, the AnyEvent + EV combination even beats the |
1697 | As you can see, the AnyEvent + EV combination even beats the |
1497 | hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl |
1698 | hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl |
1498 | backend easily beats IO::Lambda and POE. |
1699 | backend easily beats IO::Lambda and POE. |
1499 | |
1700 | |
1500 | And even the 100% non-blocking version written using the high-level (and |
1701 | And even the 100% non-blocking version written using the high-level (and |
1501 | slow :) AnyEvent::Handle abstraction beats both POE and IO::Lambda by a |
1702 | slow :) AnyEvent::Handle abstraction beats both POE and IO::Lambda |
1502 | large margin, even though it does all of DNS, tcp-connect and socket I/O |
1703 | higher level ("unoptimised") abstractions by a large margin, even though |
1503 | in a non-blocking way. |
1704 | it does all of DNS, tcp-connect and socket I/O in a non-blocking way. |
1504 | |
1705 | |
1505 | The two AnyEvent benchmarks programs can be found as eg/ae0.pl and |
1706 | The two AnyEvent benchmarks programs can be found as eg/ae0.pl and |
1506 | eg/ae2.pl in the AnyEvent distribution, the remaining benchmarks are |
1707 | eg/ae2.pl in the AnyEvent distribution, the remaining benchmarks are |
1507 | part of the IO::lambda distribution and were used without any changes. |
1708 | part of the IO::Lambda distribution and were used without any changes. |
1508 | |
1709 | |
1509 | SIGNALS |
1710 | SIGNALS |
1510 | AnyEvent currently installs handlers for these signals: |
1711 | AnyEvent currently installs handlers for these signals: |
1511 | |
1712 | |
1512 | SIGCHLD |
1713 | SIGCHLD |
1513 | A handler for "SIGCHLD" is installed by AnyEvent's child watcher |
1714 | A handler for "SIGCHLD" is installed by AnyEvent's child watcher |
1514 | emulation for event loops that do not support them natively. Also, |
1715 | emulation for event loops that do not support them natively. Also, |
1515 | some event loops install a similar handler. |
1716 | some event loops install a similar handler. |
1516 | |
1717 | |
1517 | If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent |
1718 | Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, |
1518 | will reset it to default, to avoid losing child exit statuses. |
1719 | then AnyEvent will reset it to default, to avoid losing child exit |
|
|
1720 | statuses. |
1519 | |
1721 | |
1520 | SIGPIPE |
1722 | SIGPIPE |
1521 | A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is |
1723 | A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is |
1522 | "undef" when AnyEvent gets loaded. |
1724 | "undef" when AnyEvent gets loaded. |
1523 | |
1725 | |
… | |
… | |
1531 | it is that this way, the handler will be restored to defaults on |
1733 | it is that this way, the handler will be restored to defaults on |
1532 | exec. |
1734 | exec. |
1533 | |
1735 | |
1534 | Feel free to install your own handler, or reset it to defaults. |
1736 | Feel free to install your own handler, or reset it to defaults. |
1535 | |
1737 | |
|
|
1738 | RECOMMENDED/OPTIONAL MODULES |
|
|
1739 | One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and |
|
|
1740 | it's built-in modules) are required to use it. |
|
|
1741 | |
|
|
1742 | That does not mean that AnyEvent won't take advantage of some additional |
|
|
1743 | modules if they are installed. |
|
|
1744 | |
|
|
1745 | This section explains which additional modules will be used, and how |
|
|
1746 | they affect AnyEvent's operation. |
|
|
1747 | |
|
|
1748 | Async::Interrupt |
|
|
1749 | This slightly arcane module is used to implement fast signal |
|
|
1750 | handling: To my knowledge, there is no way to do completely |
|
|
1751 | race-free and quick signal handling in pure perl. To ensure that |
|
|
1752 | signals still get delivered, AnyEvent will start an interval timer |
|
|
1753 | to wake up perl (and catch the signals) with some delay (default is |
|
|
1754 | 10 seconds, look for $AnyEvent::MAX_SIGNAL_LATENCY). |
|
|
1755 | |
|
|
1756 | If this module is available, then it will be used to implement |
|
|
1757 | signal catching, which means that signals will not be delayed, and |
|
|
1758 | the event loop will not be interrupted regularly, which is more |
|
|
1759 | efficient (and good for battery life on laptops). |
|
|
1760 | |
|
|
1761 | This affects not just the pure-perl event loop, but also other event |
|
|
1762 | loops that have no signal handling on their own (e.g. Glib, Tk, Qt). |
|
|
1763 | |
|
|
1764 | Some event loops (POE, Event, Event::Lib) offer signal watchers |
|
|
1765 | natively, and either employ their own workarounds (POE) or use |
|
|
1766 | AnyEvent's workaround (using $AnyEvent::MAX_SIGNAL_LATENCY). |
|
|
1767 | Installing Async::Interrupt does nothing for those backends. |
|
|
1768 | |
|
|
1769 | EV This module isn't really "optional", as it is simply one of the |
|
|
1770 | backend event loops that AnyEvent can use. However, it is simply the |
|
|
1771 | best event loop available in terms of features, speed and stability: |
|
|
1772 | It supports the AnyEvent API optimally, implements all the watcher |
|
|
1773 | types in XS, does automatic timer adjustments even when no monotonic |
|
|
1774 | clock is available, can take avdantage of advanced kernel interfaces |
|
|
1775 | such as "epoll" and "kqueue", and is the fastest backend *by far*. |
|
|
1776 | You can even embed Glib/Gtk2 in it (or vice versa, see EV::Glib and |
|
|
1777 | Glib::EV). |
|
|
1778 | |
|
|
1779 | Guard |
|
|
1780 | The guard module, when used, will be used to implement |
|
|
1781 | "AnyEvent::Util::guard". This speeds up guards considerably (and |
|
|
1782 | uses a lot less memory), but otherwise doesn't affect guard |
|
|
1783 | operation much. It is purely used for performance. |
|
|
1784 | |
|
|
1785 | JSON and JSON::XS |
|
|
1786 | One of these modules is required when you want to read or write JSON |
|
|
1787 | data via AnyEvent::Handle. It is also written in pure-perl, but can |
|
|
1788 | take advantage of the ultra-high-speed JSON::XS module when it is |
|
|
1789 | installed. |
|
|
1790 | |
|
|
1791 | In fact, AnyEvent::Handle will use JSON::XS by default if it is |
|
|
1792 | installed. |
|
|
1793 | |
|
|
1794 | Net::SSLeay |
|
|
1795 | Implementing TLS/SSL in Perl is certainly interesting, but not very |
|
|
1796 | worthwhile: If this module is installed, then AnyEvent::Handle (with |
|
|
1797 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
|
|
1798 | |
|
|
1799 | Time::HiRes |
|
|
1800 | This module is part of perl since release 5.008. It will be used |
|
|
1801 | when the chosen event library does not come with a timing source on |
|
|
1802 | it's own. The pure-perl event loop (AnyEvent::Impl::Perl) will |
|
|
1803 | additionally use it to try to use a monotonic clock for timing |
|
|
1804 | stability. |
|
|
1805 | |
1536 | FORK |
1806 | FORK |
1537 | Most event libraries are not fork-safe. The ones who are usually are |
1807 | Most event libraries are not fork-safe. The ones who are usually are |
1538 | because they rely on inefficient but fork-safe "select" or "poll" calls. |
1808 | because they rely on inefficient but fork-safe "select" or "poll" calls |
1539 | Only EV is fully fork-aware. |
1809 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
|
|
1810 | epoll are usually badly thought-out hacks that are incompatible with |
|
|
1811 | fork in one way or another. Only EV is fully fork-aware and ensures that |
|
|
1812 | you continue event-processing in both parent and child (or both, if you |
|
|
1813 | know what you are doing). |
|
|
1814 | |
|
|
1815 | This means that, in general, you cannot fork and do event processing in |
|
|
1816 | the child if the event library was initialised before the fork (which |
|
|
1817 | usually happens when the first AnyEvent watcher is created, or the |
|
|
1818 | library is loaded). |
1540 | |
1819 | |
1541 | If you have to fork, you must either do so *before* creating your first |
1820 | If you have to fork, you must either do so *before* creating your first |
1542 | watcher OR you must not use AnyEvent at all in the child. |
1821 | watcher OR you must not use AnyEvent at all in the child OR you must do |
|
|
1822 | something completely out of the scope of AnyEvent. |
|
|
1823 | |
|
|
1824 | The problem of doing event processing in the parent *and* the child is |
|
|
1825 | much more complicated: even for backends that *are* fork-aware or |
|
|
1826 | fork-safe, their behaviour is not usually what you want: fork clones all |
|
|
1827 | watchers, that means all timers, I/O watchers etc. are active in both |
|
|
1828 | parent and child, which is almost never what you want. USing "exec" to |
|
|
1829 | start worker children from some kind of manage rprocess is usually |
|
|
1830 | preferred, because it is much easier and cleaner, at the expense of |
|
|
1831 | having to have another binary. |
1543 | |
1832 | |
1544 | SECURITY CONSIDERATIONS |
1833 | SECURITY CONSIDERATIONS |
1545 | AnyEvent can be forced to load any event model via |
1834 | AnyEvent can be forced to load any event model via |
1546 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
1835 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
1547 | to execute arbitrary code or directly gain access, it can easily be used |
1836 | to execute arbitrary code or directly gain access, it can easily be used |
… | |
… | |
1578 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
1867 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
1579 | Event::Lib, Qt, POE. |
1868 | Event::Lib, Qt, POE. |
1580 | |
1869 | |
1581 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1870 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1582 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1871 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1583 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE. |
1872 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
|
|
1873 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. |
1584 | |
1874 | |
1585 | Non-blocking file handles, sockets, TCP clients and servers: |
1875 | Non-blocking file handles, sockets, TCP clients and servers: |
1586 | AnyEvent::Handle, AnyEvent::Socket. |
1876 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
1587 | |
1877 | |
1588 | Asynchronous DNS: AnyEvent::DNS. |
1878 | Asynchronous DNS: AnyEvent::DNS. |
1589 | |
1879 | |
1590 | Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event, |
1880 | Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event, |
1591 | |
1881 | |
1592 | Nontrivial usage examples: Net::FCP, Net::XMPP2, AnyEvent::DNS. |
1882 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::XMPP, |
|
|
1883 | AnyEvent::HTTP. |
1593 | |
1884 | |
1594 | AUTHOR |
1885 | AUTHOR |
1595 | Marc Lehmann <schmorp@schmorp.de> |
1886 | Marc Lehmann <schmorp@schmorp.de> |
1596 | http://home.schmorp.de/ |
1887 | http://home.schmorp.de/ |
1597 | |
1888 | |