… | |
… | |
63 | you linked against by calling the functions C<ev_version_major> and |
63 | you linked against by calling the functions C<ev_version_major> and |
64 | C<ev_version_minor>. If you want, you can compare against the global |
64 | C<ev_version_minor>. If you want, you can compare against the global |
65 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
65 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
66 | version of the library your program was compiled against. |
66 | version of the library your program was compiled against. |
67 | |
67 | |
68 | Usually, its a good idea to terminate if the major versions mismatch, |
68 | Usually, it's a good idea to terminate if the major versions mismatch, |
69 | as this indicates an incompatible change. Minor versions are usually |
69 | as this indicates an incompatible change. Minor versions are usually |
70 | compatible to older versions, so a larger minor version alone is usually |
70 | compatible to older versions, so a larger minor version alone is usually |
71 | not a problem. |
71 | not a problem. |
72 | |
72 | |
73 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
73 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
… | |
… | |
103 | If you use threads, a common model is to run the default event loop |
103 | If you use threads, a common model is to run the default event loop |
104 | in your main thread (or in a separate thrad) and for each thread you |
104 | in your main thread (or in a separate thrad) and for each thread you |
105 | create, you also create another event loop. Libev itself does no locking |
105 | create, you also create another event loop. Libev itself does no locking |
106 | whatsoever, so if you mix calls to the same event loop in different |
106 | whatsoever, so if you mix calls to the same event loop in different |
107 | threads, make sure you lock (this is usually a bad idea, though, even if |
107 | threads, make sure you lock (this is usually a bad idea, though, even if |
108 | done correctly, because its hideous and inefficient). |
108 | done correctly, because it's hideous and inefficient). |
109 | |
109 | |
110 | =over 4 |
110 | =over 4 |
111 | |
111 | |
112 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
112 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
113 | |
113 | |
… | |
… | |
118 | |
118 | |
119 | If you don't know what event loop to use, use the one returned from this |
119 | If you don't know what event loop to use, use the one returned from this |
120 | function. |
120 | function. |
121 | |
121 | |
122 | The flags argument can be used to specify special behaviour or specific |
122 | The flags argument can be used to specify special behaviour or specific |
123 | backends to use, and is usually specified as 0 (or EVFLAG_AUTO) |
123 | backends to use, and is usually specified as 0 (or EVFLAG_AUTO). |
124 | |
124 | |
125 | It supports the following flags: |
125 | It supports the following flags: |
126 | |
126 | |
127 | =over 4 |
127 | =over 4 |
128 | |
128 | |
129 | =item EVFLAG_AUTO |
129 | =item C<EVFLAG_AUTO> |
130 | |
130 | |
131 | The default flags value. Use this if you have no clue (its the right |
131 | The default flags value. Use this if you have no clue (it's the right |
132 | thing, believe me). |
132 | thing, believe me). |
133 | |
133 | |
134 | =item EVFLAG_NOENV |
134 | =item C<EVFLAG_NOENV> |
135 | |
135 | |
136 | If this flag bit is ored into the flag value then libev will I<not> look |
136 | If this flag bit is ored into the flag value (or the program runs setuid |
137 | at the environment variable C<LIBEV_FLAGS>. Otherwise (the default), this |
137 | or setgid) then libev will I<not> look at the environment variable |
138 | environment variable will override the flags completely. This is useful |
138 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
|
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139 | override the flags completely if it is found in the environment. This is |
139 | to try out specific backends to tets their performance, or to work around |
140 | useful to try out specific backends to test their performance, or to work |
140 | bugs. |
141 | around bugs. |
141 | |
142 | |
142 | =item EVMETHOD_SELECT portable select backend |
143 | =item C<EVMETHOD_SELECT> (portable select backend) |
143 | |
144 | |
144 | =item EVMETHOD_POLL poll backend (everywhere except windows) |
145 | =item C<EVMETHOD_POLL> (poll backend, available everywhere except on windows) |
145 | |
146 | |
146 | =item EVMETHOD_EPOLL linux only |
147 | =item C<EVMETHOD_EPOLL> (linux only) |
147 | |
148 | |
148 | =item EVMETHOD_KQUEUE some bsds only |
149 | =item C<EVMETHOD_KQUEUE> (some bsds only) |
149 | |
150 | |
150 | =item EVMETHOD_DEVPOLL solaris 8 only |
151 | =item C<EVMETHOD_DEVPOLL> (solaris 8 only) |
151 | |
152 | |
152 | =item EVMETHOD_PORT solaris 10 only |
153 | =item C<EVMETHOD_PORT> (solaris 10 only) |
153 | |
154 | |
154 | If one or more of these are ored into the flags value, then only these |
155 | If one or more of these are ored into the flags value, then only these |
155 | backends will be tried (in the reverse order as given here). If one are |
156 | backends will be tried (in the reverse order as given here). If one are |
156 | specified, any backend will do. |
157 | specified, any backend will do. |
157 | |
158 | |
… | |
… | |
166 | |
167 | |
167 | =item ev_default_destroy () |
168 | =item ev_default_destroy () |
168 | |
169 | |
169 | Destroys the default loop again (frees all memory and kernel state |
170 | Destroys the default loop again (frees all memory and kernel state |
170 | etc.). This stops all registered event watchers (by not touching them in |
171 | etc.). This stops all registered event watchers (by not touching them in |
171 | any way whatsoever, although you cnanot rely on this :). |
172 | any way whatsoever, although you cannot rely on this :). |
172 | |
173 | |
173 | =item ev_loop_destroy (loop) |
174 | =item ev_loop_destroy (loop) |
174 | |
175 | |
175 | Like C<ev_default_destroy>, but destroys an event loop created by an |
176 | Like C<ev_default_destroy>, but destroys an event loop created by an |
176 | earlier call to C<ev_loop_new>. |
177 | earlier call to C<ev_loop_new>. |
… | |
… | |
184 | |
185 | |
185 | You I<must> call this function after forking if and only if you want to |
186 | You I<must> call this function after forking if and only if you want to |
186 | use the event library in both processes. If you just fork+exec, you don't |
187 | use the event library in both processes. If you just fork+exec, you don't |
187 | have to call it. |
188 | have to call it. |
188 | |
189 | |
189 | The function itself is quite fast and its usually not a problem to call |
190 | The function itself is quite fast and it's usually not a problem to call |
190 | it just in case after a fork. To make this easy, the function will fit in |
191 | it just in case after a fork. To make this easy, the function will fit in |
191 | quite nicely into a call to C<pthread_atfork>: |
192 | quite nicely into a call to C<pthread_atfork>: |
192 | |
193 | |
193 | pthread_atfork (0, 0, ev_default_fork); |
194 | pthread_atfork (0, 0, ev_default_fork); |
194 | |
195 | |
… | |
… | |
201 | =item unsigned int ev_method (loop) |
202 | =item unsigned int ev_method (loop) |
202 | |
203 | |
203 | Returns one of the C<EVMETHOD_*> flags indicating the event backend in |
204 | Returns one of the C<EVMETHOD_*> flags indicating the event backend in |
204 | use. |
205 | use. |
205 | |
206 | |
206 | =item ev_tstamp = ev_now (loop) |
207 | =item ev_tstamp ev_now (loop) |
207 | |
208 | |
208 | Returns the current "event loop time", which is the time the event loop |
209 | Returns the current "event loop time", which is the time the event loop |
209 | got events and started processing them. This timestamp does not change |
210 | got events and started processing them. This timestamp does not change |
210 | as long as callbacks are being processed, and this is also the base time |
211 | as long as callbacks are being processed, and this is also the base time |
211 | used for relative timers. You can treat it as the timestamp of the event |
212 | used for relative timers. You can treat it as the timestamp of the event |
… | |
… | |
220 | If the flags argument is specified as 0, it will not return until either |
221 | If the flags argument is specified as 0, it will not return until either |
221 | no event watchers are active anymore or C<ev_unloop> was called. |
222 | no event watchers are active anymore or C<ev_unloop> was called. |
222 | |
223 | |
223 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
224 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
224 | those events and any outstanding ones, but will not block your process in |
225 | those events and any outstanding ones, but will not block your process in |
225 | case there are no events. |
226 | case there are no events and will return after one iteration of the loop. |
226 | |
227 | |
227 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
228 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
228 | neccessary) and will handle those and any outstanding ones. It will block |
229 | neccessary) and will handle those and any outstanding ones. It will block |
229 | your process until at least one new event arrives. |
230 | your process until at least one new event arrives, and will return after |
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231 | one iteration of the loop. |
230 | |
232 | |
231 | This flags value could be used to implement alternative looping |
233 | This flags value could be used to implement alternative looping |
232 | constructs, but the C<prepare> and C<check> watchers provide a better and |
234 | constructs, but the C<prepare> and C<check> watchers provide a better and |
233 | more generic mechanism. |
235 | more generic mechanism. |
234 | |
236 | |
235 | =item ev_unloop (loop, how) |
237 | =item ev_unloop (loop, how) |
236 | |
238 | |
237 | Can be used to make a call to C<ev_loop> return early. The C<how> argument |
239 | Can be used to make a call to C<ev_loop> return early (but only after it |
|
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240 | has processed all outstanding events). The C<how> argument must be either |
238 | must be either C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> |
241 | C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> call return, or |
239 | call return, or C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> |
242 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
240 | calls return. |
|
|
241 | |
243 | |
242 | =item ev_ref (loop) |
244 | =item ev_ref (loop) |
243 | |
245 | |
244 | =item ev_unref (loop) |
246 | =item ev_unref (loop) |
245 | |
247 | |
246 | Ref/unref can be used to add or remove a refcount on the event loop: Every |
248 | Ref/unref can be used to add or remove a reference count on the event |
247 | watcher keeps one reference. If you have a long-runing watcher you never |
249 | loop: Every watcher keeps one reference, and as long as the reference |
248 | unregister that should not keep ev_loop from running, ev_unref() after |
250 | count is nonzero, C<ev_loop> will not return on its own. If you have |
249 | starting, and ev_ref() before stopping it. Libev itself uses this for |
251 | a watcher you never unregister that should not keep C<ev_loop> from |
250 | example for its internal signal pipe: It is not visible to you as a user |
252 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
251 | and should not keep C<ev_loop> from exiting if the work is done. It is |
253 | example, libev itself uses this for its internal signal pipe: It is not |
252 | also an excellent way to do this for generic recurring timers or from |
254 | visible to the libev user and should not keep C<ev_loop> from exiting if |
253 | within third-party libraries. Just remember to unref after start and ref |
255 | no event watchers registered by it are active. It is also an excellent |
254 | before stop. |
256 | way to do this for generic recurring timers or from within third-party |
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257 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
255 | |
258 | |
256 | =back |
259 | =back |
257 | |
260 | |
258 | =head1 ANATOMY OF A WATCHER |
261 | =head1 ANATOMY OF A WATCHER |
259 | |
262 | |
260 | A watcher is a structure that you create and register to record your |
263 | A watcher is a structure that you create and register to record your |
261 | interest in some event. For instance, if you want to wait for STDIN to |
264 | interest in some event. For instance, if you want to wait for STDIN to |
262 | become readable, you would create an ev_io watcher for that: |
265 | become readable, you would create an C<ev_io> watcher for that: |
263 | |
266 | |
264 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
267 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
265 | { |
268 | { |
266 | ev_io_stop (w); |
269 | ev_io_stop (w); |
267 | ev_unloop (loop, EVUNLOOP_ALL); |
270 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
311 | (you can receive multiple events at the same time). The possible bit masks |
314 | (you can receive multiple events at the same time). The possible bit masks |
312 | are: |
315 | are: |
313 | |
316 | |
314 | =over 4 |
317 | =over 4 |
315 | |
318 | |
316 | =item EV_READ |
319 | =item C<EV_READ> |
317 | |
320 | |
318 | =item EV_WRITE |
321 | =item C<EV_WRITE> |
319 | |
322 | |
320 | The file descriptor in the ev_io watcher has become readable and/or |
323 | The file descriptor in the C<ev_io> watcher has become readable and/or |
321 | writable. |
324 | writable. |
322 | |
325 | |
323 | =item EV_TIMEOUT |
326 | =item C<EV_TIMEOUT> |
324 | |
327 | |
325 | The ev_timer watcher has timed out. |
328 | The C<ev_timer> watcher has timed out. |
326 | |
329 | |
327 | =item EV_PERIODIC |
330 | =item C<EV_PERIODIC> |
328 | |
331 | |
329 | The ev_periodic watcher has timed out. |
332 | The C<ev_periodic> watcher has timed out. |
330 | |
333 | |
331 | =item EV_SIGNAL |
334 | =item C<EV_SIGNAL> |
332 | |
335 | |
333 | The signal specified in the ev_signal watcher has been received by a thread. |
336 | The signal specified in the C<ev_signal> watcher has been received by a thread. |
334 | |
337 | |
335 | =item EV_CHILD |
338 | =item C<EV_CHILD> |
336 | |
339 | |
337 | The pid specified in the ev_child watcher has received a status change. |
340 | The pid specified in the C<ev_child> watcher has received a status change. |
338 | |
341 | |
339 | =item EV_IDLE |
342 | =item C<EV_IDLE> |
340 | |
343 | |
341 | The ev_idle watcher has determined that you have nothing better to do. |
344 | The C<ev_idle> watcher has determined that you have nothing better to do. |
342 | |
345 | |
343 | =item EV_PREPARE |
346 | =item C<EV_PREPARE> |
344 | |
347 | |
345 | =item EV_CHECK |
348 | =item C<EV_CHECK> |
346 | |
349 | |
347 | All ev_prepare watchers are invoked just I<before> C<ev_loop> starts |
350 | All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts |
348 | to gather new events, and all ev_check watchers are invoked just after |
351 | to gather new events, and all C<ev_check> watchers are invoked just after |
349 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
352 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
350 | received events. Callbacks of both watcher types can start and stop as |
353 | received events. Callbacks of both watcher types can start and stop as |
351 | many watchers as they want, and all of them will be taken into account |
354 | many watchers as they want, and all of them will be taken into account |
352 | (for example, a ev_prepare watcher might start an idle watcher to keep |
355 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
353 | C<ev_loop> from blocking). |
356 | C<ev_loop> from blocking). |
354 | |
357 | |
355 | =item EV_ERROR |
358 | =item C<EV_ERROR> |
356 | |
359 | |
357 | An unspecified error has occured, the watcher has been stopped. This might |
360 | An unspecified error has occured, the watcher has been stopped. This might |
358 | happen because the watcher could not be properly started because libev |
361 | happen because the watcher could not be properly started because libev |
359 | ran out of memory, a file descriptor was found to be closed or any other |
362 | ran out of memory, a file descriptor was found to be closed or any other |
360 | problem. You best act on it by reporting the problem and somehow coping |
363 | problem. You best act on it by reporting the problem and somehow coping |
… | |
… | |
401 | =head1 WATCHER TYPES |
404 | =head1 WATCHER TYPES |
402 | |
405 | |
403 | This section describes each watcher in detail, but will not repeat |
406 | This section describes each watcher in detail, but will not repeat |
404 | information given in the last section. |
407 | information given in the last section. |
405 | |
408 | |
406 | =head2 struct ev_io - is my file descriptor readable or writable |
409 | =head2 C<ev_io> - is this file descriptor readable or writable |
407 | |
410 | |
408 | I/O watchers check whether a file descriptor is readable or writable |
411 | I/O watchers check whether a file descriptor is readable or writable |
409 | in each iteration of the event loop (This behaviour is called |
412 | in each iteration of the event loop (This behaviour is called |
410 | level-triggering because you keep receiving events as long as the |
413 | level-triggering because you keep receiving events as long as the |
411 | condition persists. Remember you cna stop the watcher if you don't want to |
414 | condition persists. Remember you cna stop the watcher if you don't want to |
412 | act on the event and neither want to receive future events). |
415 | act on the event and neither want to receive future events). |
413 | |
416 | |
|
|
417 | In general you can register as many read and/or write event watchers oer |
|
|
418 | fd as you want (as long as you don't confuse yourself). Setting all file |
|
|
419 | descriptors to non-blocking mode is also usually a good idea (but not |
|
|
420 | required if you know what you are doing). |
|
|
421 | |
|
|
422 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
423 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
424 | descriptors correctly if you register interest in two or more fds pointing |
|
|
425 | to the same file/socket etc. description. |
|
|
426 | |
|
|
427 | If you must do this, then force the use of a known-to-be-good backend |
|
|
428 | (at the time of this writing, this includes only EVMETHOD_SELECT and |
|
|
429 | EVMETHOD_POLL). |
|
|
430 | |
414 | =over 4 |
431 | =over 4 |
415 | |
432 | |
416 | =item ev_io_init (ev_io *, callback, int fd, int events) |
433 | =item ev_io_init (ev_io *, callback, int fd, int events) |
417 | |
434 | |
418 | =item ev_io_set (ev_io *, int fd, int events) |
435 | =item ev_io_set (ev_io *, int fd, int events) |
419 | |
436 | |
420 | Configures an ev_io watcher. The fd is the file descriptor to rceeive |
437 | Configures an C<ev_io> watcher. The fd is the file descriptor to rceeive |
421 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
438 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
422 | EV_WRITE> to receive the given events. |
439 | EV_WRITE> to receive the given events. |
423 | |
440 | |
424 | =back |
441 | =back |
425 | |
442 | |
426 | =head2 struct ev_timer - relative and optionally recurring timeouts |
443 | =head2 C<ev_timer> - relative and optionally recurring timeouts |
427 | |
444 | |
428 | Timer watchers are simple relative timers that generate an event after a |
445 | Timer watchers are simple relative timers that generate an event after a |
429 | given time, and optionally repeating in regular intervals after that. |
446 | given time, and optionally repeating in regular intervals after that. |
430 | |
447 | |
431 | The timers are based on real time, that is, if you register an event that |
448 | The timers are based on real time, that is, if you register an event that |
432 | times out after an hour and youreset your system clock to last years |
449 | times out after an hour and youreset your system clock to last years |
433 | time, it will still time out after (roughly) and hour. "Roughly" because |
450 | time, it will still time out after (roughly) and hour. "Roughly" because |
434 | detecting time jumps is hard, and soem inaccuracies are unavoidable (the |
451 | detecting time jumps is hard, and soem inaccuracies are unavoidable (the |
435 | monotonic clock option helps a lot here). |
452 | monotonic clock option helps a lot here). |
436 | |
453 | |
|
|
454 | The relative timeouts are calculated relative to the C<ev_now ()> |
|
|
455 | time. This is usually the right thing as this timestamp refers to the time |
|
|
456 | of the event triggering whatever timeout you are modifying/starting. If |
|
|
457 | you suspect event processing to be delayed and you *need* to base the timeout |
|
|
458 | ion the current time, use something like this to adjust for this: |
|
|
459 | |
|
|
460 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
|
|
461 | |
437 | =over 4 |
462 | =over 4 |
438 | |
463 | |
439 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
464 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
440 | |
465 | |
441 | =item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat) |
466 | =item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat) |
… | |
… | |
463 | |
488 | |
464 | This sounds a bit complicated, but here is a useful and typical |
489 | This sounds a bit complicated, but here is a useful and typical |
465 | example: Imagine you have a tcp connection and you want a so-called idle |
490 | example: Imagine you have a tcp connection and you want a so-called idle |
466 | timeout, that is, you want to be called when there have been, say, 60 |
491 | timeout, that is, you want to be called when there have been, say, 60 |
467 | seconds of inactivity on the socket. The easiest way to do this is to |
492 | seconds of inactivity on the socket. The easiest way to do this is to |
468 | configure an ev_timer with after=repeat=60 and calling ev_timer_again each |
493 | configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each |
469 | time you successfully read or write some data. If you go into an idle |
494 | time you successfully read or write some data. If you go into an idle |
470 | state where you do not expect data to travel on the socket, you can stop |
495 | state where you do not expect data to travel on the socket, you can stop |
471 | the timer, and again will automatically restart it if need be. |
496 | the timer, and again will automatically restart it if need be. |
472 | |
497 | |
473 | =back |
498 | =back |
474 | |
499 | |
475 | =head2 ev_periodic - to cron or not to cron it |
500 | =head2 C<ev_periodic> - to cron or not to cron it |
476 | |
501 | |
477 | Periodic watchers are also timers of a kind, but they are very versatile |
502 | Periodic watchers are also timers of a kind, but they are very versatile |
478 | (and unfortunately a bit complex). |
503 | (and unfortunately a bit complex). |
479 | |
504 | |
480 | Unlike ev_timer's, they are not based on real time (or relative time) |
505 | Unlike C<ev_timer>'s, they are not based on real time (or relative time) |
481 | but on wallclock time (absolute time). You can tell a periodic watcher |
506 | but on wallclock time (absolute time). You can tell a periodic watcher |
482 | to trigger "at" some specific point in time. For example, if you tell a |
507 | to trigger "at" some specific point in time. For example, if you tell a |
483 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
508 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
484 | + 10.>) and then reset your system clock to the last year, then it will |
509 | + 10.>) and then reset your system clock to the last year, then it will |
485 | take a year to trigger the event (unlike an ev_timer, which would trigger |
510 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
486 | roughly 10 seconds later and of course not if you reset your system time |
511 | roughly 10 seconds later and of course not if you reset your system time |
487 | again). |
512 | again). |
488 | |
513 | |
489 | They can also be used to implement vastly more complex timers, such as |
514 | They can also be used to implement vastly more complex timers, such as |
490 | triggering an event on eahc midnight, local time. |
515 | triggering an event on eahc midnight, local time. |
… | |
… | |
523 | but only that the the callback will be called when the system time shows a |
548 | but only that the the callback will be called when the system time shows a |
524 | full hour (UTC), or more correct, when the system time is evenly divisible |
549 | full hour (UTC), or more correct, when the system time is evenly divisible |
525 | by 3600. |
550 | by 3600. |
526 | |
551 | |
527 | Another way to think about it (for the mathematically inclined) is that |
552 | Another way to think about it (for the mathematically inclined) is that |
528 | ev_periodic will try to run the callback in this mode at the next possible |
553 | C<ev_periodic> will try to run the callback in this mode at the next possible |
529 | time where C<time = at (mod interval)>, regardless of any time jumps. |
554 | time where C<time = at (mod interval)>, regardless of any time jumps. |
530 | |
555 | |
531 | =item * manual reschedule mode (reschedule_cb = callback) |
556 | =item * manual reschedule mode (reschedule_cb = callback) |
532 | |
557 | |
533 | In this mode the values for C<interval> and C<at> are both being |
558 | In this mode the values for C<interval> and C<at> are both being |
… | |
… | |
566 | a different time than the last time it was called (e.g. in a crond like |
591 | a different time than the last time it was called (e.g. in a crond like |
567 | program when the crontabs have changed). |
592 | program when the crontabs have changed). |
568 | |
593 | |
569 | =back |
594 | =back |
570 | |
595 | |
571 | =head2 ev_signal - signal me when a signal gets signalled |
596 | =head2 C<ev_signal> - signal me when a signal gets signalled |
572 | |
597 | |
573 | Signal watchers will trigger an event when the process receives a specific |
598 | Signal watchers will trigger an event when the process receives a specific |
574 | signal one or more times. Even though signals are very asynchronous, libev |
599 | signal one or more times. Even though signals are very asynchronous, libev |
575 | will try its best to deliver signals synchronously, i.e. as part of the |
600 | will try it's best to deliver signals synchronously, i.e. as part of the |
576 | normal event processing, like any other event. |
601 | normal event processing, like any other event. |
577 | |
602 | |
578 | You cna configure as many watchers as you like per signal. Only when the |
603 | You cna configure as many watchers as you like per signal. Only when the |
579 | first watcher gets started will libev actually register a signal watcher |
604 | first watcher gets started will libev actually register a signal watcher |
580 | with the kernel (thus it coexists with your own signal handlers as long |
605 | with the kernel (thus it coexists with your own signal handlers as long |
… | |
… | |
591 | Configures the watcher to trigger on the given signal number (usually one |
616 | Configures the watcher to trigger on the given signal number (usually one |
592 | of the C<SIGxxx> constants). |
617 | of the C<SIGxxx> constants). |
593 | |
618 | |
594 | =back |
619 | =back |
595 | |
620 | |
596 | =head2 ev_child - wait for pid status changes |
621 | =head2 C<ev_child> - wait for pid status changes |
597 | |
622 | |
598 | Child watchers trigger when your process receives a SIGCHLD in response to |
623 | Child watchers trigger when your process receives a SIGCHLD in response to |
599 | some child status changes (most typically when a child of yours dies). |
624 | some child status changes (most typically when a child of yours dies). |
600 | |
625 | |
601 | =over 4 |
626 | =over 4 |
… | |
… | |
610 | the status word (use the macros from C<sys/wait.h>). The C<rpid> member |
635 | the status word (use the macros from C<sys/wait.h>). The C<rpid> member |
611 | contains the pid of the process causing the status change. |
636 | contains the pid of the process causing the status change. |
612 | |
637 | |
613 | =back |
638 | =back |
614 | |
639 | |
615 | =head2 ev_idle - when you've got nothing better to do |
640 | =head2 C<ev_idle> - when you've got nothing better to do |
616 | |
641 | |
617 | Idle watchers trigger events when there are no other I/O or timer (or |
642 | Idle watchers trigger events when there are no other I/O or timer (or |
618 | periodic) events pending. That is, as long as your process is busy |
643 | periodic) events pending. That is, as long as your process is busy |
619 | handling sockets or timeouts it will not be called. But when your process |
644 | handling sockets or timeouts it will not be called. But when your process |
620 | is idle all idle watchers are being called again and again - until |
645 | is idle all idle watchers are being called again and again - until |
… | |
… | |
647 | Their main purpose is to integrate other event mechanisms into libev. This |
672 | Their main purpose is to integrate other event mechanisms into libev. This |
648 | could be used, for example, to track variable changes, implement your own |
673 | could be used, for example, to track variable changes, implement your own |
649 | watchers, integrate net-snmp or a coroutine library and lots more. |
674 | watchers, integrate net-snmp or a coroutine library and lots more. |
650 | |
675 | |
651 | This is done by examining in each prepare call which file descriptors need |
676 | This is done by examining in each prepare call which file descriptors need |
652 | to be watched by the other library, registering ev_io watchers for them |
677 | to be watched by the other library, registering C<ev_io> watchers for them |
653 | and starting an ev_timer watcher for any timeouts (many libraries provide |
678 | and starting an C<ev_timer> watcher for any timeouts (many libraries provide |
654 | just this functionality). Then, in the check watcher you check for any |
679 | just this functionality). Then, in the check watcher you check for any |
655 | events that occured (by making your callbacks set soem flags for example) |
680 | events that occured (by making your callbacks set soem flags for example) |
656 | and call back into the library. |
681 | and call back into the library. |
657 | |
682 | |
658 | As another example, the perl Coro module uses these hooks to integrate |
683 | As another example, the perl Coro module uses these hooks to integrate |
… | |
… | |
685 | watchers. This is useful if you want to wait for a single event on an fd |
710 | watchers. This is useful if you want to wait for a single event on an fd |
686 | or timeout without havign to allocate/configure/start/stop/free one or |
711 | or timeout without havign to allocate/configure/start/stop/free one or |
687 | more watchers yourself. |
712 | more watchers yourself. |
688 | |
713 | |
689 | If C<fd> is less than 0, then no I/O watcher will be started and events is |
714 | If C<fd> is less than 0, then no I/O watcher will be started and events is |
690 | ignored. Otherwise, an ev_io watcher for the given C<fd> and C<events> set |
715 | ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and C<events> set |
691 | will be craeted and started. |
716 | will be craeted and started. |
692 | |
717 | |
693 | If C<timeout> is less than 0, then no timeout watcher will be |
718 | If C<timeout> is less than 0, then no timeout watcher will be |
694 | started. Otherwise an ev_timer watcher with after = C<timeout> (and repeat |
719 | started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and repeat |
695 | = 0) will be started. |
720 | = 0) will be started. |
696 | |
721 | |
697 | The callback has the type C<void (*cb)(int revents, void *arg)> and |
722 | The callback has the type C<void (*cb)(int revents, void *arg)> and |
698 | gets passed an events set (normally a combination of EV_ERROR, EV_READ, |
723 | gets passed an events set (normally a combination of C<EV_ERROR>, C<EV_READ>, |
699 | EV_WRITE or EV_TIMEOUT) and the C<arg> value passed to C<ev_once>: |
724 | C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg> value passed to C<ev_once>: |
700 | |
725 | |
701 | static void stdin_ready (int revents, void *arg) |
726 | static void stdin_ready (int revents, void *arg) |
702 | { |
727 | { |
703 | if (revents & EV_TIMEOUT) |
728 | if (revents & EV_TIMEOUT) |
704 | /* doh, nothing entered */ |
729 | /* doh, nothing entered */ |