… | |
… | |
127 | .\} |
127 | .\} |
128 | .rm #[ #] #H #V #F C |
128 | .rm #[ #] #H #V #F C |
129 | .\" ======================================================================== |
129 | .\" ======================================================================== |
130 | .\" |
130 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-28" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
137 | .Vb 1 |
138 | \& #include <ev.h> |
138 | \& #include <ev.h> |
139 | .Ve |
139 | .Ve |
|
|
140 | .SH "EXAMPLE PROGRAM" |
|
|
141 | .IX Header "EXAMPLE PROGRAM" |
|
|
142 | .Vb 1 |
|
|
143 | \& #include <ev.h> |
|
|
144 | .Ve |
|
|
145 | .PP |
|
|
146 | .Vb 2 |
|
|
147 | \& ev_io stdin_watcher; |
|
|
148 | \& ev_timer timeout_watcher; |
|
|
149 | .Ve |
|
|
150 | .PP |
|
|
151 | .Vb 8 |
|
|
152 | \& /* called when data readable on stdin */ |
|
|
153 | \& static void |
|
|
154 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
|
|
155 | \& { |
|
|
156 | \& /* puts ("stdin ready"); */ |
|
|
157 | \& ev_io_stop (EV_A_ w); /* just a syntax example */ |
|
|
158 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
|
|
159 | \& } |
|
|
160 | .Ve |
|
|
161 | .PP |
|
|
162 | .Vb 6 |
|
|
163 | \& static void |
|
|
164 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
165 | \& { |
|
|
166 | \& /* puts ("timeout"); */ |
|
|
167 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
|
|
168 | \& } |
|
|
169 | .Ve |
|
|
170 | .PP |
|
|
171 | .Vb 4 |
|
|
172 | \& int |
|
|
173 | \& main (void) |
|
|
174 | \& { |
|
|
175 | \& struct ev_loop *loop = ev_default_loop (0); |
|
|
176 | .Ve |
|
|
177 | .PP |
|
|
178 | .Vb 3 |
|
|
179 | \& /* initialise an io watcher, then start it */ |
|
|
180 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
|
|
181 | \& ev_io_start (loop, &stdin_watcher); |
|
|
182 | .Ve |
|
|
183 | .PP |
|
|
184 | .Vb 3 |
|
|
185 | \& /* simple non-repeating 5.5 second timeout */ |
|
|
186 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
|
|
187 | \& ev_timer_start (loop, &timeout_watcher); |
|
|
188 | .Ve |
|
|
189 | .PP |
|
|
190 | .Vb 2 |
|
|
191 | \& /* loop till timeout or data ready */ |
|
|
192 | \& ev_loop (loop, 0); |
|
|
193 | .Ve |
|
|
194 | .PP |
|
|
195 | .Vb 2 |
|
|
196 | \& return 0; |
|
|
197 | \& } |
|
|
198 | .Ve |
140 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
141 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
142 | Libev is an event loop: you register interest in certain events (such as a |
201 | Libev is an event loop: you register interest in certain events (such as a |
143 | file descriptor being readable or a timeout occuring), and it will manage |
202 | file descriptor being readable or a timeout occuring), and it will manage |
144 | these event sources and provide your program with events. |
203 | these event sources and provide your program with events. |
… | |
… | |
151 | watchers\fR, which are relatively small C structures you initialise with the |
210 | watchers\fR, which are relatively small C structures you initialise with the |
152 | details of the event, and then hand it over to libev by \fIstarting\fR the |
211 | details of the event, and then hand it over to libev by \fIstarting\fR the |
153 | watcher. |
212 | watcher. |
154 | .SH "FEATURES" |
213 | .SH "FEATURES" |
155 | .IX Header "FEATURES" |
214 | .IX Header "FEATURES" |
156 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
215 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
157 | kqueue mechanisms for file descriptor events, relative timers, absolute |
216 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
158 | timers with customised rescheduling, signal events, process status change |
217 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
159 | events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event |
218 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
160 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
219 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
161 | fast (see this benchmark comparing |
220 | (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and event |
162 | it to libevent for example). |
221 | watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
|
|
222 | \&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as |
|
|
223 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
|
|
224 | (\f(CW\*(C`ev_fork\*(C'\fR). |
|
|
225 | .PP |
|
|
226 | It also is quite fast (see this |
|
|
227 | benchmark comparing it to libevent |
|
|
228 | for example). |
163 | .SH "CONVENTIONS" |
229 | .SH "CONVENTIONS" |
164 | .IX Header "CONVENTIONS" |
230 | .IX Header "CONVENTIONS" |
165 | Libev is very configurable. In this manual the default configuration |
231 | Libev is very configurable. In this manual the default configuration will |
166 | will be described, which supports multiple event loops. For more info |
232 | be described, which supports multiple event loops. For more info about |
167 | about various configuration options please have a look at the file |
233 | various configuration options please have a look at \fB\s-1EMBED\s0\fR section in |
168 | \&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without |
234 | this manual. If libev was configured without support for multiple event |
169 | support for multiple event loops, then all functions taking an initial |
235 | loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR |
170 | argument of name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) |
236 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
171 | will not have this argument. |
|
|
172 | .SH "TIME REPRESENTATION" |
237 | .SH "TIME REPRESENTATION" |
173 | .IX Header "TIME REPRESENTATION" |
238 | .IX Header "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
239 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
240 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
176 | the beginning of 1970, details are complicated, don't ask). This type is |
241 | the beginning of 1970, details are complicated, don't ask). This type is |
… | |
… | |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
266 | Usually, it's a good idea to terminate if the major versions mismatch, |
202 | as this indicates an incompatible change. Minor versions are usually |
267 | as this indicates an incompatible change. Minor versions are usually |
203 | compatible to older versions, so a larger minor version alone is usually |
268 | compatible to older versions, so a larger minor version alone is usually |
204 | not a problem. |
269 | not a problem. |
205 | .Sp |
270 | .Sp |
206 | Example: make sure we haven't accidentally been linked against the wrong |
271 | Example: Make sure we haven't accidentally been linked against the wrong |
207 | version: |
272 | version. |
208 | .Sp |
273 | .Sp |
209 | .Vb 3 |
274 | .Vb 3 |
210 | \& assert (("libev version mismatch", |
275 | \& assert (("libev version mismatch", |
211 | \& ev_version_major () == EV_VERSION_MAJOR |
276 | \& ev_version_major () == EV_VERSION_MAJOR |
212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
277 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
… | |
… | |
242 | recommended ones. |
307 | recommended ones. |
243 | .Sp |
308 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
309 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
310 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
311 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
312 | Sets the allocation function to use (the prototype is similar \- the |
248 | realloc C function, the semantics are identical). It is used to allocate |
313 | semantics is identical \- to the realloc C function). It is used to |
249 | and free memory (no surprises here). If it returns zero when memory |
314 | allocate and free memory (no surprises here). If it returns zero when |
250 | needs to be allocated, the library might abort or take some potentially |
315 | memory needs to be allocated, the library might abort or take some |
251 | destructive action. The default is your system realloc function. |
316 | potentially destructive action. The default is your system realloc |
|
|
317 | function. |
252 | .Sp |
318 | .Sp |
253 | You could override this function in high-availability programs to, say, |
319 | You could override this function in high-availability programs to, say, |
254 | free some memory if it cannot allocate memory, to use a special allocator, |
320 | free some memory if it cannot allocate memory, to use a special allocator, |
255 | or even to sleep a while and retry until some memory is available. |
321 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
322 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
323 | Example: Replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
324 | retries). |
259 | .Sp |
325 | .Sp |
260 | .Vb 6 |
326 | .Vb 6 |
261 | \& static void * |
327 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
328 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
329 | \& { |
264 | \& for (;;) |
330 | \& for (;;) |
265 | \& { |
331 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
332 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
333 | .Ve |
… | |
… | |
289 | callback is set, then libev will expect it to remedy the sitution, no |
355 | callback is set, then libev will expect it to remedy the sitution, no |
290 | matter what, when it returns. That is, libev will generally retry the |
356 | matter what, when it returns. That is, libev will generally retry the |
291 | requested operation, or, if the condition doesn't go away, do bad stuff |
357 | requested operation, or, if the condition doesn't go away, do bad stuff |
292 | (such as abort). |
358 | (such as abort). |
293 | .Sp |
359 | .Sp |
294 | Example: do the same thing as libev does internally: |
360 | Example: This is basically the same thing that libev does internally, too. |
295 | .Sp |
361 | .Sp |
296 | .Vb 6 |
362 | .Vb 6 |
297 | \& static void |
363 | \& static void |
298 | \& fatal_error (const char *msg) |
364 | \& fatal_error (const char *msg) |
299 | \& { |
365 | \& { |
… | |
… | |
448 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
514 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
449 | always distinct from the default loop. Unlike the default loop, it cannot |
515 | always distinct from the default loop. Unlike the default loop, it cannot |
450 | handle signal and child watchers, and attempts to do so will be greeted by |
516 | handle signal and child watchers, and attempts to do so will be greeted by |
451 | undefined behaviour (or a failed assertion if assertions are enabled). |
517 | undefined behaviour (or a failed assertion if assertions are enabled). |
452 | .Sp |
518 | .Sp |
453 | Example: try to create a event loop that uses epoll and nothing else. |
519 | Example: Try to create a event loop that uses epoll and nothing else. |
454 | .Sp |
520 | .Sp |
455 | .Vb 3 |
521 | .Vb 3 |
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
522 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
457 | \& if (!epoller) |
523 | \& if (!epoller) |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
524 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
459 | .Ve |
525 | .Ve |
460 | .IP "ev_default_destroy ()" 4 |
526 | .IP "ev_default_destroy ()" 4 |
461 | .IX Item "ev_default_destroy ()" |
527 | .IX Item "ev_default_destroy ()" |
462 | Destroys the default loop again (frees all memory and kernel state |
528 | Destroys the default loop again (frees all memory and kernel state |
463 | etc.). This stops all registered event watchers (by not touching them in |
529 | etc.). None of the active event watchers will be stopped in the normal |
464 | any way whatsoever, although you cannot rely on this :). |
530 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
|
|
531 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
|
|
532 | calling this function, or cope with the fact afterwards (which is usually |
|
|
533 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
|
|
534 | for example). |
465 | .IP "ev_loop_destroy (loop)" 4 |
535 | .IP "ev_loop_destroy (loop)" 4 |
466 | .IX Item "ev_loop_destroy (loop)" |
536 | .IX Item "ev_loop_destroy (loop)" |
467 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
537 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
468 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
538 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
469 | .IP "ev_default_fork ()" 4 |
539 | .IP "ev_default_fork ()" 4 |
… | |
… | |
552 | \& be handled here by queueing them when their watcher gets executed. |
622 | \& be handled here by queueing them when their watcher gets executed. |
553 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
623 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
554 | \& were used, return, otherwise continue with step *. |
624 | \& were used, return, otherwise continue with step *. |
555 | .Ve |
625 | .Ve |
556 | .Sp |
626 | .Sp |
557 | Example: queue some jobs and then loop until no events are outsanding |
627 | Example: Queue some jobs and then loop until no events are outsanding |
558 | anymore. |
628 | anymore. |
559 | .Sp |
629 | .Sp |
560 | .Vb 4 |
630 | .Vb 4 |
561 | \& ... queue jobs here, make sure they register event watchers as long |
631 | \& ... queue jobs here, make sure they register event watchers as long |
562 | \& ... as they still have work to do (even an idle watcher will do..) |
632 | \& ... as they still have work to do (even an idle watcher will do..) |
… | |
… | |
584 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
654 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
585 | no event watchers registered by it are active. It is also an excellent |
655 | no event watchers registered by it are active. It is also an excellent |
586 | way to do this for generic recurring timers or from within third-party |
656 | way to do this for generic recurring timers or from within third-party |
587 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
657 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
588 | .Sp |
658 | .Sp |
589 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
659 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
590 | running when nothing else is active. |
660 | running when nothing else is active. |
591 | .Sp |
661 | .Sp |
592 | .Vb 4 |
662 | .Vb 4 |
593 | \& struct dv_signal exitsig; |
663 | \& struct ev_signal exitsig; |
594 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
664 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
595 | \& ev_signal_start (myloop, &exitsig); |
665 | \& ev_signal_start (loop, &exitsig); |
596 | \& evf_unref (myloop); |
666 | \& evf_unref (loop); |
597 | .Ve |
667 | .Ve |
598 | .Sp |
668 | .Sp |
599 | Example: for some weird reason, unregister the above signal handler again. |
669 | Example: For some weird reason, unregister the above signal handler again. |
600 | .Sp |
670 | .Sp |
601 | .Vb 2 |
671 | .Vb 2 |
602 | \& ev_ref (myloop); |
672 | \& ev_ref (loop); |
603 | \& ev_signal_stop (myloop, &exitsig); |
673 | \& ev_signal_stop (loop, &exitsig); |
604 | .Ve |
674 | .Ve |
605 | .SH "ANATOMY OF A WATCHER" |
675 | .SH "ANATOMY OF A WATCHER" |
606 | .IX Header "ANATOMY OF A WATCHER" |
676 | .IX Header "ANATOMY OF A WATCHER" |
607 | A watcher is a structure that you create and register to record your |
677 | A watcher is a structure that you create and register to record your |
608 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
678 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
… | |
… | |
645 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
715 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
646 | corresponding stop function (\f(CW\*(C`ev_<type>_stop (loop, watcher *)\*(C'\fR. |
716 | corresponding stop function (\f(CW\*(C`ev_<type>_stop (loop, watcher *)\*(C'\fR. |
647 | .PP |
717 | .PP |
648 | As long as your watcher is active (has been started but not stopped) you |
718 | As long as your watcher is active (has been started but not stopped) you |
649 | must not touch the values stored in it. Most specifically you must never |
719 | must not touch the values stored in it. Most specifically you must never |
650 | reinitialise it or call its set macro. |
720 | reinitialise it or call its \f(CW\*(C`set\*(C'\fR macro. |
651 | .PP |
|
|
652 | You can check whether an event is active by calling the \f(CW\*(C`ev_is_active |
|
|
653 | (watcher *)\*(C'\fR macro. To see whether an event is outstanding (but the |
|
|
654 | callback for it has not been called yet) you can use the \f(CW\*(C`ev_is_pending |
|
|
655 | (watcher *)\*(C'\fR macro. |
|
|
656 | .PP |
721 | .PP |
657 | Each and every callback receives the event loop pointer as first, the |
722 | Each and every callback receives the event loop pointer as first, the |
658 | registered watcher structure as second, and a bitset of received events as |
723 | registered watcher structure as second, and a bitset of received events as |
659 | third argument. |
724 | third argument. |
660 | .PP |
725 | .PP |
… | |
… | |
685 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
750 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
686 | .ie n .IP """EV_CHILD""" 4 |
751 | .ie n .IP """EV_CHILD""" 4 |
687 | .el .IP "\f(CWEV_CHILD\fR" 4 |
752 | .el .IP "\f(CWEV_CHILD\fR" 4 |
688 | .IX Item "EV_CHILD" |
753 | .IX Item "EV_CHILD" |
689 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
754 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
755 | .ie n .IP """EV_STAT""" 4 |
|
|
756 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
757 | .IX Item "EV_STAT" |
|
|
758 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
690 | .ie n .IP """EV_IDLE""" 4 |
759 | .ie n .IP """EV_IDLE""" 4 |
691 | .el .IP "\f(CWEV_IDLE\fR" 4 |
760 | .el .IP "\f(CWEV_IDLE\fR" 4 |
692 | .IX Item "EV_IDLE" |
761 | .IX Item "EV_IDLE" |
693 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
762 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
694 | .ie n .IP """EV_PREPARE""" 4 |
763 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
704 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
773 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
705 | received events. Callbacks of both watcher types can start and stop as |
774 | received events. Callbacks of both watcher types can start and stop as |
706 | many watchers as they want, and all of them will be taken into account |
775 | many watchers as they want, and all of them will be taken into account |
707 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
776 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
708 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
777 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
778 | .ie n .IP """EV_EMBED""" 4 |
|
|
779 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
780 | .IX Item "EV_EMBED" |
|
|
781 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
782 | .ie n .IP """EV_FORK""" 4 |
|
|
783 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
784 | .IX Item "EV_FORK" |
|
|
785 | The event loop has been resumed in the child process after fork (see |
|
|
786 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
709 | .ie n .IP """EV_ERROR""" 4 |
787 | .ie n .IP """EV_ERROR""" 4 |
710 | .el .IP "\f(CWEV_ERROR\fR" 4 |
788 | .el .IP "\f(CWEV_ERROR\fR" 4 |
711 | .IX Item "EV_ERROR" |
789 | .IX Item "EV_ERROR" |
712 | An unspecified error has occured, the watcher has been stopped. This might |
790 | An unspecified error has occured, the watcher has been stopped. This might |
713 | happen because the watcher could not be properly started because libev |
791 | happen because the watcher could not be properly started because libev |
… | |
… | |
718 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
796 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
719 | for example it might indicate that a fd is readable or writable, and if |
797 | for example it might indicate that a fd is readable or writable, and if |
720 | your callbacks is well-written it can just attempt the operation and cope |
798 | your callbacks is well-written it can just attempt the operation and cope |
721 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
799 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
722 | programs, though, so beware. |
800 | programs, though, so beware. |
|
|
801 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
|
|
802 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
|
|
803 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
|
|
804 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
|
|
805 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
|
|
806 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
|
|
807 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
|
|
808 | This macro initialises the generic portion of a watcher. The contents |
|
|
809 | of the watcher object can be arbitrary (so \f(CW\*(C`malloc\*(C'\fR will do). Only |
|
|
810 | the generic parts of the watcher are initialised, you \fIneed\fR to call |
|
|
811 | the type-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR macro afterwards to initialise the |
|
|
812 | type-specific parts. For each type there is also a \f(CW\*(C`ev_TYPE_init\*(C'\fR macro |
|
|
813 | which rolls both calls into one. |
|
|
814 | .Sp |
|
|
815 | You can reinitialise a watcher at any time as long as it has been stopped |
|
|
816 | (or never started) and there are no pending events outstanding. |
|
|
817 | .Sp |
|
|
818 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
|
|
819 | int revents)\*(C'\fR. |
|
|
820 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
|
|
821 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
|
|
822 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
|
|
823 | This macro initialises the type-specific parts of a watcher. You need to |
|
|
824 | call \f(CW\*(C`ev_init\*(C'\fR at least once before you call this macro, but you can |
|
|
825 | call \f(CW\*(C`ev_TYPE_set\*(C'\fR any number of times. You must not, however, call this |
|
|
826 | macro on a watcher that is active (it can be pending, however, which is a |
|
|
827 | difference to the \f(CW\*(C`ev_init\*(C'\fR macro). |
|
|
828 | .Sp |
|
|
829 | Although some watcher types do not have type-specific arguments |
|
|
830 | (e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro. |
|
|
831 | .ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4 |
|
|
832 | .el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4 |
|
|
833 | .IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])" |
|
|
834 | This convinience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro |
|
|
835 | calls into a single call. This is the most convinient method to initialise |
|
|
836 | a watcher. The same limitations apply, of course. |
|
|
837 | .ie n .IP """ev_TYPE_start"" (loop *, ev_TYPE *watcher)" 4 |
|
|
838 | .el .IP "\f(CWev_TYPE_start\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
839 | .IX Item "ev_TYPE_start (loop *, ev_TYPE *watcher)" |
|
|
840 | Starts (activates) the given watcher. Only active watchers will receive |
|
|
841 | events. If the watcher is already active nothing will happen. |
|
|
842 | .ie n .IP """ev_TYPE_stop"" (loop *, ev_TYPE *watcher)" 4 |
|
|
843 | .el .IP "\f(CWev_TYPE_stop\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
844 | .IX Item "ev_TYPE_stop (loop *, ev_TYPE *watcher)" |
|
|
845 | Stops the given watcher again (if active) and clears the pending |
|
|
846 | status. It is possible that stopped watchers are pending (for example, |
|
|
847 | non-repeating timers are being stopped when they become pending), but |
|
|
848 | \&\f(CW\*(C`ev_TYPE_stop\*(C'\fR ensures that the watcher is neither active nor pending. If |
|
|
849 | you want to free or reuse the memory used by the watcher it is therefore a |
|
|
850 | good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
|
|
851 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
|
|
852 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
|
|
853 | Returns a true value iff the watcher is active (i.e. it has been started |
|
|
854 | and not yet been stopped). As long as a watcher is active you must not modify |
|
|
855 | it. |
|
|
856 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
|
|
857 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
|
|
858 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
|
|
859 | events but its callback has not yet been invoked). As long as a watcher |
|
|
860 | is pending (but not active) you must not call an init function on it (but |
|
|
861 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
|
|
862 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
|
|
863 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
|
|
864 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
|
|
865 | Returns the callback currently set on the watcher. |
|
|
866 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
|
|
867 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
|
|
868 | Change the callback. You can change the callback at virtually any time |
|
|
869 | (modulo threads). |
723 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
870 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
724 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
871 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
725 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
872 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
726 | and read at any time, libev will completely ignore it. This can be used |
873 | and read at any time, libev will completely ignore it. This can be used |
727 | to associate arbitrary data with your watcher. If you need more data and |
874 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
748 | \& struct my_io *w = (struct my_io *)w_; |
895 | \& struct my_io *w = (struct my_io *)w_; |
749 | \& ... |
896 | \& ... |
750 | \& } |
897 | \& } |
751 | .Ve |
898 | .Ve |
752 | .PP |
899 | .PP |
753 | More interesting and less C\-conformant ways of catsing your callback type |
900 | More interesting and less C\-conformant ways of casting your callback type |
754 | have been omitted.... |
901 | instead have been omitted. |
|
|
902 | .PP |
|
|
903 | Another common scenario is having some data structure with multiple |
|
|
904 | watchers: |
|
|
905 | .PP |
|
|
906 | .Vb 6 |
|
|
907 | \& struct my_biggy |
|
|
908 | \& { |
|
|
909 | \& int some_data; |
|
|
910 | \& ev_timer t1; |
|
|
911 | \& ev_timer t2; |
|
|
912 | \& } |
|
|
913 | .Ve |
|
|
914 | .PP |
|
|
915 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
916 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
917 | .PP |
|
|
918 | .Vb 1 |
|
|
919 | \& #include <stddef.h> |
|
|
920 | .Ve |
|
|
921 | .PP |
|
|
922 | .Vb 6 |
|
|
923 | \& static void |
|
|
924 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
925 | \& { |
|
|
926 | \& struct my_biggy big = (struct my_biggy * |
|
|
927 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
928 | \& } |
|
|
929 | .Ve |
|
|
930 | .PP |
|
|
931 | .Vb 6 |
|
|
932 | \& static void |
|
|
933 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
934 | \& { |
|
|
935 | \& struct my_biggy big = (struct my_biggy * |
|
|
936 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
937 | \& } |
|
|
938 | .Ve |
755 | .SH "WATCHER TYPES" |
939 | .SH "WATCHER TYPES" |
756 | .IX Header "WATCHER TYPES" |
940 | .IX Header "WATCHER TYPES" |
757 | This section describes each watcher in detail, but will not repeat |
941 | This section describes each watcher in detail, but will not repeat |
758 | information given in the last section. |
942 | information given in the last section. Any initialisation/set macros, |
|
|
943 | functions and members specific to the watcher type are explained. |
|
|
944 | .PP |
|
|
945 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
946 | while the watcher is active, you can look at the member and expect some |
|
|
947 | sensible content, but you must not modify it (you can modify it while the |
|
|
948 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
949 | means you can expect it to have some sensible content while the watcher |
|
|
950 | is active, but you can also modify it. Modifying it may not do something |
|
|
951 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
952 | not crash or malfunction in any way. |
759 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
953 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
760 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable" |
954 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
761 | .IX Subsection "ev_io - is this file descriptor readable or writable" |
955 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
762 | I/O watchers check whether a file descriptor is readable or writable |
956 | I/O watchers check whether a file descriptor is readable or writable |
763 | in each iteration of the event loop (This behaviour is called |
957 | in each iteration of the event loop, or, more precisely, when reading |
764 | level-triggering because you keep receiving events as long as the |
958 | would not block the process and writing would at least be able to write |
765 | condition persists. Remember you can stop the watcher if you don't want to |
959 | some data. This behaviour is called level-triggering because you keep |
766 | act on the event and neither want to receive future events). |
960 | receiving events as long as the condition persists. Remember you can stop |
|
|
961 | the watcher if you don't want to act on the event and neither want to |
|
|
962 | receive future events. |
767 | .PP |
963 | .PP |
768 | In general you can register as many read and/or write event watchers per |
964 | In general you can register as many read and/or write event watchers per |
769 | fd as you want (as long as you don't confuse yourself). Setting all file |
965 | fd as you want (as long as you don't confuse yourself). Setting all file |
770 | descriptors to non-blocking mode is also usually a good idea (but not |
966 | descriptors to non-blocking mode is also usually a good idea (but not |
771 | required if you know what you are doing). |
967 | required if you know what you are doing). |
772 | .PP |
968 | .PP |
773 | You have to be careful with dup'ed file descriptors, though. Some backends |
969 | You have to be careful with dup'ed file descriptors, though. Some backends |
774 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
970 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
775 | descriptors correctly if you register interest in two or more fds pointing |
971 | descriptors correctly if you register interest in two or more fds pointing |
776 | to the same underlying file/socket etc. description (that is, they share |
972 | to the same underlying file/socket/etc. description (that is, they share |
777 | the same underlying \*(L"file open\*(R"). |
973 | the same underlying \*(L"file open\*(R"). |
778 | .PP |
974 | .PP |
779 | If you must do this, then force the use of a known-to-be-good backend |
975 | If you must do this, then force the use of a known-to-be-good backend |
780 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
976 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
781 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
977 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
|
|
978 | .PP |
|
|
979 | Another thing you have to watch out for is that it is quite easy to |
|
|
980 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
|
|
981 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
|
|
982 | because there is no data. Not only are some backends known to create a |
|
|
983 | lot of those (for example solaris ports), it is very easy to get into |
|
|
984 | this situation even with a relatively standard program structure. Thus |
|
|
985 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
|
|
986 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
|
|
987 | .PP |
|
|
988 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
989 | play around with an Xlib connection), then you have to seperately re-test |
|
|
990 | wether a file descriptor is really ready with a known-to-be good interface |
|
|
991 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
992 | its own, so its quite safe to use). |
782 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
993 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
783 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
994 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
784 | .PD 0 |
995 | .PD 0 |
785 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
996 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
786 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
997 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
787 | .PD |
998 | .PD |
788 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
999 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
789 | events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_READ | |
1000 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
790 | EV_WRITE\*(C'\fR to receive the given events. |
1001 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
791 | .Sp |
1002 | .IP "int fd [read\-only]" 4 |
792 | Please note that most of the more scalable backend mechanisms (for example |
1003 | .IX Item "int fd [read-only]" |
793 | epoll and solaris ports) can result in spurious readyness notifications |
1004 | The file descriptor being watched. |
794 | for file descriptors, so you practically need to use non-blocking I/O (and |
1005 | .IP "int events [read\-only]" 4 |
795 | treat callback invocation as hint only), or retest separately with a safe |
1006 | .IX Item "int events [read-only]" |
796 | interface before doing I/O (XLib can do this), or force the use of either |
1007 | The events being watched. |
797 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR, which don't suffer from this |
|
|
798 | problem. Also note that it is quite easy to have your callback invoked |
|
|
799 | when the readyness condition is no longer valid even when employing |
|
|
800 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
801 | I/O unconditionally. |
|
|
802 | .PP |
1008 | .PP |
803 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1009 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
804 | readable, but only once. Since it is likely line\-buffered, you could |
1010 | readable, but only once. Since it is likely line\-buffered, you could |
805 | attempt to read a whole line in the callback: |
1011 | attempt to read a whole line in the callback. |
806 | .PP |
1012 | .PP |
807 | .Vb 6 |
1013 | .Vb 6 |
808 | \& static void |
1014 | \& static void |
809 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1015 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
810 | \& { |
1016 | \& { |
… | |
… | |
819 | \& struct ev_io stdin_readable; |
1025 | \& struct ev_io stdin_readable; |
820 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1026 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
821 | \& ev_io_start (loop, &stdin_readable); |
1027 | \& ev_io_start (loop, &stdin_readable); |
822 | \& ev_loop (loop, 0); |
1028 | \& ev_loop (loop, 0); |
823 | .Ve |
1029 | .Ve |
824 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
1030 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
825 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
1031 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
826 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
1032 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
827 | Timer watchers are simple relative timers that generate an event after a |
1033 | Timer watchers are simple relative timers that generate an event after a |
828 | given time, and optionally repeating in regular intervals after that. |
1034 | given time, and optionally repeating in regular intervals after that. |
829 | .PP |
1035 | .PP |
830 | The timers are based on real time, that is, if you register an event that |
1036 | The timers are based on real time, that is, if you register an event that |
831 | times out after an hour and you reset your system clock to last years |
1037 | times out after an hour and you reset your system clock to last years |
… | |
… | |
871 | .Sp |
1077 | .Sp |
872 | If the timer is repeating, either start it if necessary (with the repeat |
1078 | If the timer is repeating, either start it if necessary (with the repeat |
873 | value), or reset the running timer to the repeat value. |
1079 | value), or reset the running timer to the repeat value. |
874 | .Sp |
1080 | .Sp |
875 | This sounds a bit complicated, but here is a useful and typical |
1081 | This sounds a bit complicated, but here is a useful and typical |
876 | example: Imagine you have a tcp connection and you want a so-called idle |
1082 | example: Imagine you have a tcp connection and you want a so-called |
877 | timeout, that is, you want to be called when there have been, say, 60 |
1083 | idle timeout, that is, you want to be called when there have been, |
878 | seconds of inactivity on the socket. The easiest way to do this is to |
1084 | say, 60 seconds of inactivity on the socket. The easiest way to do |
879 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1085 | this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling |
880 | time you successfully read or write some data. If you go into an idle |
1086 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
881 | state where you do not expect data to travel on the socket, you can stop |
1087 | you go into an idle state where you do not expect data to travel on the |
882 | the timer, and again will automatically restart it if need be. |
1088 | socket, you can stop the timer, and again will automatically restart it if |
|
|
1089 | need be. |
|
|
1090 | .Sp |
|
|
1091 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
|
|
1092 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
|
|
1093 | .Sp |
|
|
1094 | .Vb 8 |
|
|
1095 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
1096 | \& ev_timer_again (loop, timer); |
|
|
1097 | \& ... |
|
|
1098 | \& timer->again = 17.; |
|
|
1099 | \& ev_timer_again (loop, timer); |
|
|
1100 | \& ... |
|
|
1101 | \& timer->again = 10.; |
|
|
1102 | \& ev_timer_again (loop, timer); |
|
|
1103 | .Ve |
|
|
1104 | .Sp |
|
|
1105 | This is more efficient then stopping/starting the timer eahc time you want |
|
|
1106 | to modify its timeout value. |
|
|
1107 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1108 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1109 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1110 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1111 | which is also when any modifications are taken into account. |
883 | .PP |
1112 | .PP |
884 | Example: create a timer that fires after 60 seconds. |
1113 | Example: Create a timer that fires after 60 seconds. |
885 | .PP |
1114 | .PP |
886 | .Vb 5 |
1115 | .Vb 5 |
887 | \& static void |
1116 | \& static void |
888 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1117 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
889 | \& { |
1118 | \& { |
… | |
… | |
895 | \& struct ev_timer mytimer; |
1124 | \& struct ev_timer mytimer; |
896 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1125 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
897 | \& ev_timer_start (loop, &mytimer); |
1126 | \& ev_timer_start (loop, &mytimer); |
898 | .Ve |
1127 | .Ve |
899 | .PP |
1128 | .PP |
900 | Example: create a timeout timer that times out after 10 seconds of |
1129 | Example: Create a timeout timer that times out after 10 seconds of |
901 | inactivity. |
1130 | inactivity. |
902 | .PP |
1131 | .PP |
903 | .Vb 5 |
1132 | .Vb 5 |
904 | \& static void |
1133 | \& static void |
905 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1134 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
918 | .Vb 3 |
1147 | .Vb 3 |
919 | \& // and in some piece of code that gets executed on any "activity": |
1148 | \& // and in some piece of code that gets executed on any "activity": |
920 | \& // reset the timeout to start ticking again at 10 seconds |
1149 | \& // reset the timeout to start ticking again at 10 seconds |
921 | \& ev_timer_again (&mytimer); |
1150 | \& ev_timer_again (&mytimer); |
922 | .Ve |
1151 | .Ve |
923 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
1152 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
924 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
1153 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
925 | .IX Subsection "ev_periodic - to cron or not to cron" |
1154 | .IX Subsection "ev_periodic - to cron or not to cron?" |
926 | Periodic watchers are also timers of a kind, but they are very versatile |
1155 | Periodic watchers are also timers of a kind, but they are very versatile |
927 | (and unfortunately a bit complex). |
1156 | (and unfortunately a bit complex). |
928 | .PP |
1157 | .PP |
929 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1158 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
930 | but on wallclock time (absolute time). You can tell a periodic watcher |
1159 | but on wallclock time (absolute time). You can tell a periodic watcher |
931 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1160 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
932 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
1161 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
933 | + 10.>) and then reset your system clock to the last year, then it will |
1162 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
934 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1163 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
935 | roughly 10 seconds later and of course not if you reset your system time |
1164 | roughly 10 seconds later and of course not if you reset your system time |
936 | again). |
1165 | again). |
937 | .PP |
1166 | .PP |
938 | They can also be used to implement vastly more complex timers, such as |
1167 | They can also be used to implement vastly more complex timers, such as |
… | |
… | |
1019 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1248 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1020 | Simply stops and restarts the periodic watcher again. This is only useful |
1249 | Simply stops and restarts the periodic watcher again. This is only useful |
1021 | when you changed some parameters or the reschedule callback would return |
1250 | when you changed some parameters or the reschedule callback would return |
1022 | a different time than the last time it was called (e.g. in a crond like |
1251 | a different time than the last time it was called (e.g. in a crond like |
1023 | program when the crontabs have changed). |
1252 | program when the crontabs have changed). |
|
|
1253 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1254 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1255 | The current interval value. Can be modified any time, but changes only |
|
|
1256 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1257 | called. |
|
|
1258 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1259 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1260 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1261 | switched off. Can be changed any time, but changes only take effect when |
|
|
1262 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1024 | .PP |
1263 | .PP |
1025 | Example: call a callback every hour, or, more precisely, whenever the |
1264 | Example: Call a callback every hour, or, more precisely, whenever the |
1026 | system clock is divisible by 3600. The callback invocation times have |
1265 | system clock is divisible by 3600. The callback invocation times have |
1027 | potentially a lot of jittering, but good long-term stability. |
1266 | potentially a lot of jittering, but good long-term stability. |
1028 | .PP |
1267 | .PP |
1029 | .Vb 5 |
1268 | .Vb 5 |
1030 | \& static void |
1269 | \& static void |
… | |
… | |
1038 | \& struct ev_periodic hourly_tick; |
1277 | \& struct ev_periodic hourly_tick; |
1039 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1278 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1040 | \& ev_periodic_start (loop, &hourly_tick); |
1279 | \& ev_periodic_start (loop, &hourly_tick); |
1041 | .Ve |
1280 | .Ve |
1042 | .PP |
1281 | .PP |
1043 | Example: the same as above, but use a reschedule callback to do it: |
1282 | Example: The same as above, but use a reschedule callback to do it: |
1044 | .PP |
1283 | .PP |
1045 | .Vb 1 |
1284 | .Vb 1 |
1046 | \& #include <math.h> |
1285 | \& #include <math.h> |
1047 | .Ve |
1286 | .Ve |
1048 | .PP |
1287 | .PP |
… | |
… | |
1056 | .PP |
1295 | .PP |
1057 | .Vb 1 |
1296 | .Vb 1 |
1058 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1297 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1059 | .Ve |
1298 | .Ve |
1060 | .PP |
1299 | .PP |
1061 | Example: call a callback every hour, starting now: |
1300 | Example: Call a callback every hour, starting now: |
1062 | .PP |
1301 | .PP |
1063 | .Vb 4 |
1302 | .Vb 4 |
1064 | \& struct ev_periodic hourly_tick; |
1303 | \& struct ev_periodic hourly_tick; |
1065 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1304 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1066 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1305 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1067 | \& ev_periodic_start (loop, &hourly_tick); |
1306 | \& ev_periodic_start (loop, &hourly_tick); |
1068 | .Ve |
1307 | .Ve |
1069 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1308 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
1070 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1309 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
1071 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1310 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
1072 | Signal watchers will trigger an event when the process receives a specific |
1311 | Signal watchers will trigger an event when the process receives a specific |
1073 | signal one or more times. Even though signals are very asynchronous, libev |
1312 | signal one or more times. Even though signals are very asynchronous, libev |
1074 | will try it's best to deliver signals synchronously, i.e. as part of the |
1313 | will try it's best to deliver signals synchronously, i.e. as part of the |
1075 | normal event processing, like any other event. |
1314 | normal event processing, like any other event. |
1076 | .PP |
1315 | .PP |
… | |
… | |
1086 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1325 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1087 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1326 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1088 | .PD |
1327 | .PD |
1089 | Configures the watcher to trigger on the given signal number (usually one |
1328 | Configures the watcher to trigger on the given signal number (usually one |
1090 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1329 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1330 | .IP "int signum [read\-only]" 4 |
|
|
1331 | .IX Item "int signum [read-only]" |
|
|
1332 | The signal the watcher watches out for. |
1091 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1333 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1092 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1334 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1093 | .IX Subsection "ev_child - wait for pid status changes" |
1335 | .IX Subsection "ev_child - watch out for process status changes" |
1094 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1336 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1095 | some child status changes (most typically when a child of yours dies). |
1337 | some child status changes (most typically when a child of yours dies). |
1096 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1338 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1097 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1339 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1098 | .PD 0 |
1340 | .PD 0 |
… | |
… | |
1103 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1345 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1104 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1346 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1105 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1347 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1106 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1348 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1107 | process causing the status change. |
1349 | process causing the status change. |
|
|
1350 | .IP "int pid [read\-only]" 4 |
|
|
1351 | .IX Item "int pid [read-only]" |
|
|
1352 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1353 | .IP "int rpid [read\-write]" 4 |
|
|
1354 | .IX Item "int rpid [read-write]" |
|
|
1355 | The process id that detected a status change. |
|
|
1356 | .IP "int rstatus [read\-write]" 4 |
|
|
1357 | .IX Item "int rstatus [read-write]" |
|
|
1358 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1359 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1108 | .PP |
1360 | .PP |
1109 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1361 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1110 | .PP |
1362 | .PP |
1111 | .Vb 5 |
1363 | .Vb 5 |
1112 | \& static void |
1364 | \& static void |
1113 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1365 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1114 | \& { |
1366 | \& { |
… | |
… | |
1119 | .Vb 3 |
1371 | .Vb 3 |
1120 | \& struct ev_signal signal_watcher; |
1372 | \& struct ev_signal signal_watcher; |
1121 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1373 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1122 | \& ev_signal_start (loop, &sigint_cb); |
1374 | \& ev_signal_start (loop, &sigint_cb); |
1123 | .Ve |
1375 | .Ve |
|
|
1376 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1377 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1378 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1379 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1380 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1381 | compared to the last time, invoking the callback if it did. |
|
|
1382 | .PP |
|
|
1383 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1384 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1385 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1386 | otherwise always forced to be at least one) and all the other fields of |
|
|
1387 | the stat buffer having unspecified contents. |
|
|
1388 | .PP |
|
|
1389 | Since there is no standard to do this, the portable implementation simply |
|
|
1390 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
|
|
1391 | can specify a recommended polling interval for this case. If you specify |
|
|
1392 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1393 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1394 | five seconds, although this might change dynamically). Libev will also |
|
|
1395 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1396 | usually overkill. |
|
|
1397 | .PP |
|
|
1398 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1399 | as even with OS-supported change notifications, this can be |
|
|
1400 | resource\-intensive. |
|
|
1401 | .PP |
|
|
1402 | At the time of this writing, only the Linux inotify interface is |
|
|
1403 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1404 | reader). Inotify will be used to give hints only and should not change the |
|
|
1405 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1406 | to fall back to regular polling again even with inotify, but changes are |
|
|
1407 | usually detected immediately, and if the file exists there will be no |
|
|
1408 | polling. |
|
|
1409 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1410 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1411 | .PD 0 |
|
|
1412 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1413 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1414 | .PD |
|
|
1415 | Configures the watcher to wait for status changes of the given |
|
|
1416 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1417 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1418 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1419 | path for as long as the watcher is active. |
|
|
1420 | .Sp |
|
|
1421 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1422 | relative to the attributes at the time the watcher was started (or the |
|
|
1423 | last change was detected). |
|
|
1424 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1425 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1426 | Updates the stat buffer immediately with new values. If you change the |
|
|
1427 | watched path in your callback, you could call this fucntion to avoid |
|
|
1428 | detecting this change (while introducing a race condition). Can also be |
|
|
1429 | useful simply to find out the new values. |
|
|
1430 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1431 | .IX Item "ev_statdata attr [read-only]" |
|
|
1432 | The most-recently detected attributes of the file. Although the type is of |
|
|
1433 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1434 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1435 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1436 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1437 | .IX Item "ev_statdata prev [read-only]" |
|
|
1438 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1439 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1440 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1441 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1442 | The specified interval. |
|
|
1443 | .IP "const char *path [read\-only]" 4 |
|
|
1444 | .IX Item "const char *path [read-only]" |
|
|
1445 | The filesystem path that is being watched. |
|
|
1446 | .PP |
|
|
1447 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1448 | .PP |
|
|
1449 | .Vb 15 |
|
|
1450 | \& static void |
|
|
1451 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1452 | \& { |
|
|
1453 | \& /* /etc/passwd changed in some way */ |
|
|
1454 | \& if (w->attr.st_nlink) |
|
|
1455 | \& { |
|
|
1456 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1457 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1458 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1459 | \& } |
|
|
1460 | \& else |
|
|
1461 | \& /* you shalt not abuse printf for puts */ |
|
|
1462 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1463 | \& "if this is windows, they already arrived\en"); |
|
|
1464 | \& } |
|
|
1465 | .Ve |
|
|
1466 | .PP |
|
|
1467 | .Vb 2 |
|
|
1468 | \& ... |
|
|
1469 | \& ev_stat passwd; |
|
|
1470 | .Ve |
|
|
1471 | .PP |
|
|
1472 | .Vb 2 |
|
|
1473 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1474 | \& ev_stat_start (loop, &passwd); |
|
|
1475 | .Ve |
1124 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1476 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1125 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1477 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1126 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1478 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1127 | Idle watchers trigger events when there are no other events are pending |
1479 | Idle watchers trigger events when there are no other events are pending |
1128 | (prepare, check and other idle watchers do not count). That is, as long |
1480 | (prepare, check and other idle watchers do not count). That is, as long |
1129 | as your process is busy handling sockets or timeouts (or even signals, |
1481 | as your process is busy handling sockets or timeouts (or even signals, |
1130 | imagine) it will not be triggered. But when your process is idle all idle |
1482 | imagine) it will not be triggered. But when your process is idle all idle |
1131 | watchers are being called again and again, once per event loop iteration \- |
1483 | watchers are being called again and again, once per event loop iteration \- |
… | |
… | |
1143 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1495 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1144 | Initialises and configures the idle watcher \- it has no parameters of any |
1496 | Initialises and configures the idle watcher \- it has no parameters of any |
1145 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1497 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1146 | believe me. |
1498 | believe me. |
1147 | .PP |
1499 | .PP |
1148 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1500 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1149 | callback, free it. Alos, use no error checking, as usual. |
1501 | callback, free it. Also, use no error checking, as usual. |
1150 | .PP |
1502 | .PP |
1151 | .Vb 7 |
1503 | .Vb 7 |
1152 | \& static void |
1504 | \& static void |
1153 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1505 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1154 | \& { |
1506 | \& { |
… | |
… | |
1161 | .Vb 3 |
1513 | .Vb 3 |
1162 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1514 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1163 | \& ev_idle_init (idle_watcher, idle_cb); |
1515 | \& ev_idle_init (idle_watcher, idle_cb); |
1164 | \& ev_idle_start (loop, idle_cb); |
1516 | \& ev_idle_start (loop, idle_cb); |
1165 | .Ve |
1517 | .Ve |
1166 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1518 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
1167 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1519 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
1168 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1520 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1169 | Prepare and check watchers are usually (but not always) used in tandem: |
1521 | Prepare and check watchers are usually (but not always) used in tandem: |
1170 | prepare watchers get invoked before the process blocks and check watchers |
1522 | prepare watchers get invoked before the process blocks and check watchers |
1171 | afterwards. |
1523 | afterwards. |
1172 | .PP |
1524 | .PP |
|
|
1525 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1526 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1527 | watchers. Other loops than the current one are fine, however. The |
|
|
1528 | rationale behind this is that you do not need to check for recursion in |
|
|
1529 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1530 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1531 | called in pairs bracketing the blocking call. |
|
|
1532 | .PP |
1173 | Their main purpose is to integrate other event mechanisms into libev and |
1533 | Their main purpose is to integrate other event mechanisms into libev and |
1174 | their use is somewhat advanced. This could be used, for example, to track |
1534 | their use is somewhat advanced. This could be used, for example, to track |
1175 | variable changes, implement your own watchers, integrate net-snmp or a |
1535 | variable changes, implement your own watchers, integrate net-snmp or a |
1176 | coroutine library and lots more. |
1536 | coroutine library and lots more. They are also occasionally useful if |
|
|
1537 | you cache some data and want to flush it before blocking (for example, |
|
|
1538 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1539 | watcher). |
1177 | .PP |
1540 | .PP |
1178 | This is done by examining in each prepare call which file descriptors need |
1541 | This is done by examining in each prepare call which file descriptors need |
1179 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1542 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1180 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1543 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1181 | provide just this functionality). Then, in the check watcher you check for |
1544 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1200 | .PD |
1563 | .PD |
1201 | Initialises and configures the prepare or check watcher \- they have no |
1564 | Initialises and configures the prepare or check watcher \- they have no |
1202 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1565 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1203 | macros, but using them is utterly, utterly and completely pointless. |
1566 | macros, but using them is utterly, utterly and completely pointless. |
1204 | .PP |
1567 | .PP |
1205 | Example: *TODO*. |
1568 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
|
|
1569 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1570 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1571 | pseudo-code only of course: |
|
|
1572 | .PP |
|
|
1573 | .Vb 2 |
|
|
1574 | \& static ev_io iow [nfd]; |
|
|
1575 | \& static ev_timer tw; |
|
|
1576 | .Ve |
|
|
1577 | .PP |
|
|
1578 | .Vb 9 |
|
|
1579 | \& static void |
|
|
1580 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1581 | \& { |
|
|
1582 | \& // set the relevant poll flags |
|
|
1583 | \& // could also call adns_processreadable etc. here |
|
|
1584 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1585 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1586 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1587 | \& } |
|
|
1588 | .Ve |
|
|
1589 | .PP |
|
|
1590 | .Vb 7 |
|
|
1591 | \& // create io watchers for each fd and a timer before blocking |
|
|
1592 | \& static void |
|
|
1593 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1594 | \& { |
|
|
1595 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1596 | \& // actual code will need to loop here and realloc etc. |
|
|
1597 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1598 | .Ve |
|
|
1599 | .PP |
|
|
1600 | .Vb 3 |
|
|
1601 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1602 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1603 | \& ev_timer_start (loop, &tw); |
|
|
1604 | .Ve |
|
|
1605 | .PP |
|
|
1606 | .Vb 6 |
|
|
1607 | \& // create on ev_io per pollfd |
|
|
1608 | \& for (int i = 0; i < nfd; ++i) |
|
|
1609 | \& { |
|
|
1610 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1611 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1612 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1613 | .Ve |
|
|
1614 | .PP |
|
|
1615 | .Vb 5 |
|
|
1616 | \& fds [i].revents = 0; |
|
|
1617 | \& iow [i].data = fds + i; |
|
|
1618 | \& ev_io_start (loop, iow + i); |
|
|
1619 | \& } |
|
|
1620 | \& } |
|
|
1621 | .Ve |
|
|
1622 | .PP |
|
|
1623 | .Vb 5 |
|
|
1624 | \& // stop all watchers after blocking |
|
|
1625 | \& static void |
|
|
1626 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1627 | \& { |
|
|
1628 | \& ev_timer_stop (loop, &tw); |
|
|
1629 | .Ve |
|
|
1630 | .PP |
|
|
1631 | .Vb 2 |
|
|
1632 | \& for (int i = 0; i < nfd; ++i) |
|
|
1633 | \& ev_io_stop (loop, iow + i); |
|
|
1634 | .Ve |
|
|
1635 | .PP |
|
|
1636 | .Vb 2 |
|
|
1637 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1638 | \& } |
|
|
1639 | .Ve |
1206 | .ie n .Sh """ev_embed"" \- when one backend isn't enough" |
1640 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1207 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough" |
1641 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1208 | .IX Subsection "ev_embed - when one backend isn't enough" |
1642 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1209 | This is a rather advanced watcher type that lets you embed one event loop |
1643 | This is a rather advanced watcher type that lets you embed one event loop |
1210 | into another. |
1644 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
|
|
1645 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1646 | fashion and must not be used). |
1211 | .PP |
1647 | .PP |
1212 | There are primarily two reasons you would want that: work around bugs and |
1648 | There are primarily two reasons you would want that: work around bugs and |
1213 | prioritise I/O. |
1649 | prioritise I/O. |
1214 | .PP |
1650 | .PP |
1215 | As an example for a bug workaround, the kqueue backend might only support |
1651 | As an example for a bug workaround, the kqueue backend might only support |
… | |
… | |
1223 | As for prioritising I/O: rarely you have the case where some fds have |
1659 | As for prioritising I/O: rarely you have the case where some fds have |
1224 | to be watched and handled very quickly (with low latency), and even |
1660 | to be watched and handled very quickly (with low latency), and even |
1225 | priorities and idle watchers might have too much overhead. In this case |
1661 | priorities and idle watchers might have too much overhead. In this case |
1226 | you would put all the high priority stuff in one loop and all the rest in |
1662 | you would put all the high priority stuff in one loop and all the rest in |
1227 | a second one, and embed the second one in the first. |
1663 | a second one, and embed the second one in the first. |
|
|
1664 | .PP |
|
|
1665 | As long as the watcher is active, the callback will be invoked every time |
|
|
1666 | there might be events pending in the embedded loop. The callback must then |
|
|
1667 | call \f(CW\*(C`ev_embed_sweep (mainloop, watcher)\*(C'\fR to make a single sweep and invoke |
|
|
1668 | their callbacks (you could also start an idle watcher to give the embedded |
|
|
1669 | loop strictly lower priority for example). You can also set the callback |
|
|
1670 | to \f(CW0\fR, in which case the embed watcher will automatically execute the |
|
|
1671 | embedded loop sweep. |
1228 | .PP |
1672 | .PP |
1229 | As long as the watcher is started it will automatically handle events. The |
1673 | As long as the watcher is started it will automatically handle events. The |
1230 | callback will be invoked whenever some events have been handled. You can |
1674 | callback will be invoked whenever some events have been handled. You can |
1231 | set the callback to \f(CW0\fR to avoid having to specify one if you are not |
1675 | set the callback to \f(CW0\fR to avoid having to specify one if you are not |
1232 | interested in that. |
1676 | interested in that. |
… | |
… | |
1267 | \& ev_embed_start (loop_hi, &embed); |
1711 | \& ev_embed_start (loop_hi, &embed); |
1268 | \& } |
1712 | \& } |
1269 | \& else |
1713 | \& else |
1270 | \& loop_lo = loop_hi; |
1714 | \& loop_lo = loop_hi; |
1271 | .Ve |
1715 | .Ve |
1272 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *loop)" 4 |
1716 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1273 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *loop)" |
1717 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1274 | .PD 0 |
1718 | .PD 0 |
1275 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *loop)" 4 |
1719 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1276 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *loop)" |
1720 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1277 | .PD |
1721 | .PD |
1278 | Configures the watcher to embed the given loop, which must be embeddable. |
1722 | Configures the watcher to embed the given loop, which must be |
|
|
1723 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
|
|
1724 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1725 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1726 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1727 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
|
|
1728 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
|
|
1729 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1730 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
|
|
1731 | apropriate way for embedded loops. |
|
|
1732 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1733 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1734 | The embedded event loop. |
|
|
1735 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1736 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1737 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1738 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1739 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1740 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1741 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1742 | and only in the child after the fork. If whoever good citizen calling |
|
|
1743 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1744 | handlers will be invoked, too, of course. |
|
|
1745 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
1746 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
1747 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1748 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1749 | believe me. |
1279 | .SH "OTHER FUNCTIONS" |
1750 | .SH "OTHER FUNCTIONS" |
1280 | .IX Header "OTHER FUNCTIONS" |
1751 | .IX Header "OTHER FUNCTIONS" |
1281 | There are some other functions of possible interest. Described. Here. Now. |
1752 | There are some other functions of possible interest. Described. Here. Now. |
1282 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1753 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1283 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1754 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1312 | .Ve |
1783 | .Ve |
1313 | .Sp |
1784 | .Sp |
1314 | .Vb 1 |
1785 | .Vb 1 |
1315 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1786 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1316 | .Ve |
1787 | .Ve |
1317 | .IP "ev_feed_event (loop, watcher, int events)" 4 |
1788 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
1318 | .IX Item "ev_feed_event (loop, watcher, int events)" |
1789 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
1319 | Feeds the given event set into the event loop, as if the specified event |
1790 | Feeds the given event set into the event loop, as if the specified event |
1320 | had happened for the specified watcher (which must be a pointer to an |
1791 | had happened for the specified watcher (which must be a pointer to an |
1321 | initialised but not necessarily started event watcher). |
1792 | initialised but not necessarily started event watcher). |
1322 | .IP "ev_feed_fd_event (loop, int fd, int revents)" 4 |
1793 | .IP "ev_feed_fd_event (ev_loop *, int fd, int revents)" 4 |
1323 | .IX Item "ev_feed_fd_event (loop, int fd, int revents)" |
1794 | .IX Item "ev_feed_fd_event (ev_loop *, int fd, int revents)" |
1324 | Feed an event on the given fd, as if a file descriptor backend detected |
1795 | Feed an event on the given fd, as if a file descriptor backend detected |
1325 | the given events it. |
1796 | the given events it. |
1326 | .IP "ev_feed_signal_event (loop, int signum)" 4 |
1797 | .IP "ev_feed_signal_event (ev_loop *loop, int signum)" 4 |
1327 | .IX Item "ev_feed_signal_event (loop, int signum)" |
1798 | .IX Item "ev_feed_signal_event (ev_loop *loop, int signum)" |
1328 | Feed an event as if the given signal occured (loop must be the default loop!). |
1799 | Feed an event as if the given signal occured (\f(CW\*(C`loop\*(C'\fR must be the default |
|
|
1800 | loop!). |
1329 | .SH "LIBEVENT EMULATION" |
1801 | .SH "LIBEVENT EMULATION" |
1330 | .IX Header "LIBEVENT EMULATION" |
1802 | .IX Header "LIBEVENT EMULATION" |
1331 | Libev offers a compatibility emulation layer for libevent. It cannot |
1803 | Libev offers a compatibility emulation layer for libevent. It cannot |
1332 | emulate the internals of libevent, so here are some usage hints: |
1804 | emulate the internals of libevent, so here are some usage hints: |
1333 | .IP "* Use it by including <event.h>, as usual." 4 |
1805 | .IP "* Use it by including <event.h>, as usual." 4 |
… | |
… | |
1344 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1816 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1345 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1817 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1346 | .PD |
1818 | .PD |
1347 | .SH "\*(C+ SUPPORT" |
1819 | .SH "\*(C+ SUPPORT" |
1348 | .IX Header " SUPPORT" |
1820 | .IX Header " SUPPORT" |
1349 | \&\s-1TBD\s0. |
1821 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
|
|
1822 | you to use some convinience methods to start/stop watchers and also change |
|
|
1823 | the callback model to a model using method callbacks on objects. |
|
|
1824 | .PP |
|
|
1825 | To use it, |
|
|
1826 | .PP |
|
|
1827 | .Vb 1 |
|
|
1828 | \& #include <ev++.h> |
|
|
1829 | .Ve |
|
|
1830 | .PP |
|
|
1831 | (it is not installed by default). This automatically includes \fIev.h\fR |
|
|
1832 | and puts all of its definitions (many of them macros) into the global |
|
|
1833 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
|
|
1834 | .PP |
|
|
1835 | It should support all the same embedding options as \fIev.h\fR, most notably |
|
|
1836 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
|
|
1837 | .PP |
|
|
1838 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
|
|
1839 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
|
|
1840 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
|
|
1841 | .IX Item "ev::READ, ev::WRITE etc." |
|
|
1842 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
|
|
1843 | macros from \fIev.h\fR. |
|
|
1844 | .ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4 |
|
|
1845 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
|
|
1846 | .IX Item "ev::tstamp, ev::now" |
|
|
1847 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
|
|
1848 | .ie n .IP """ev::io""\fR, \f(CW""ev::timer""\fR, \f(CW""ev::periodic""\fR, \f(CW""ev::idle""\fR, \f(CW""ev::sig"" etc." 4 |
|
|
1849 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
|
|
1850 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
|
|
1851 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
|
|
1852 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
|
|
1853 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
|
|
1854 | defines by many implementations. |
|
|
1855 | .Sp |
|
|
1856 | All of those classes have these methods: |
|
|
1857 | .RS 4 |
|
|
1858 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
|
|
1859 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
|
|
1860 | .PD 0 |
|
|
1861 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
|
|
1862 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
|
|
1863 | .IP "ev::TYPE::~TYPE" 4 |
|
|
1864 | .IX Item "ev::TYPE::~TYPE" |
|
|
1865 | .PD |
|
|
1866 | The constructor takes a pointer to an object and a method pointer to |
|
|
1867 | the event handler callback to call in this class. The constructor calls |
|
|
1868 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
|
|
1869 | before starting it. If you do not specify a loop then the constructor |
|
|
1870 | automatically associates the default loop with this watcher. |
|
|
1871 | .Sp |
|
|
1872 | The destructor automatically stops the watcher if it is active. |
|
|
1873 | .IP "w\->set (struct ev_loop *)" 4 |
|
|
1874 | .IX Item "w->set (struct ev_loop *)" |
|
|
1875 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
|
|
1876 | do this when the watcher is inactive (and not pending either). |
|
|
1877 | .IP "w\->set ([args])" 4 |
|
|
1878 | .IX Item "w->set ([args])" |
|
|
1879 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
|
|
1880 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1881 | automatically stopped and restarted. |
|
|
1882 | .IP "w\->start ()" 4 |
|
|
1883 | .IX Item "w->start ()" |
|
|
1884 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
|
|
1885 | constructor already takes the loop. |
|
|
1886 | .IP "w\->stop ()" 4 |
|
|
1887 | .IX Item "w->stop ()" |
|
|
1888 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
|
|
1889 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
|
|
1890 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
|
|
1891 | .IX Item "w->again () ev::timer, ev::periodic only" |
|
|
1892 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
|
|
1893 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
|
|
1894 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
|
|
1895 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
|
|
1896 | .IX Item "w->sweep () ev::embed only" |
|
|
1897 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1898 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
1899 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
1900 | .IX Item "w->update () ev::stat only" |
|
|
1901 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
|
|
1902 | .RE |
|
|
1903 | .RS 4 |
|
|
1904 | .RE |
|
|
1905 | .PP |
|
|
1906 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
|
|
1907 | the constructor. |
|
|
1908 | .PP |
|
|
1909 | .Vb 4 |
|
|
1910 | \& class myclass |
|
|
1911 | \& { |
|
|
1912 | \& ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1913 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1914 | .Ve |
|
|
1915 | .PP |
|
|
1916 | .Vb 2 |
|
|
1917 | \& myclass (); |
|
|
1918 | \& } |
|
|
1919 | .Ve |
|
|
1920 | .PP |
|
|
1921 | .Vb 6 |
|
|
1922 | \& myclass::myclass (int fd) |
|
|
1923 | \& : io (this, &myclass::io_cb), |
|
|
1924 | \& idle (this, &myclass::idle_cb) |
|
|
1925 | \& { |
|
|
1926 | \& io.start (fd, ev::READ); |
|
|
1927 | \& } |
|
|
1928 | .Ve |
|
|
1929 | .SH "MACRO MAGIC" |
|
|
1930 | .IX Header "MACRO MAGIC" |
|
|
1931 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1932 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
|
|
1933 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
1934 | .PP |
|
|
1935 | To make it easier to write programs that cope with either variant, the |
|
|
1936 | following macros are defined: |
|
|
1937 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
1938 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
1939 | .IX Item "EV_A, EV_A_" |
|
|
1940 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
1941 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
1942 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
1943 | .Sp |
|
|
1944 | .Vb 3 |
|
|
1945 | \& ev_unref (EV_A); |
|
|
1946 | \& ev_timer_add (EV_A_ watcher); |
|
|
1947 | \& ev_loop (EV_A_ 0); |
|
|
1948 | .Ve |
|
|
1949 | .Sp |
|
|
1950 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
1951 | which is often provided by the following macro. |
|
|
1952 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
1953 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
1954 | .IX Item "EV_P, EV_P_" |
|
|
1955 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
1956 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
1957 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
1958 | .Sp |
|
|
1959 | .Vb 2 |
|
|
1960 | \& // this is how ev_unref is being declared |
|
|
1961 | \& static void ev_unref (EV_P); |
|
|
1962 | .Ve |
|
|
1963 | .Sp |
|
|
1964 | .Vb 2 |
|
|
1965 | \& // this is how you can declare your typical callback |
|
|
1966 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1967 | .Ve |
|
|
1968 | .Sp |
|
|
1969 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
1970 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
1971 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
1972 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
1973 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
1974 | Similar to the other two macros, this gives you the value of the default |
|
|
1975 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
1976 | .PP |
|
|
1977 | Example: Declare and initialise a check watcher, working regardless of |
|
|
1978 | wether multiple loops are supported or not. |
|
|
1979 | .PP |
|
|
1980 | .Vb 5 |
|
|
1981 | \& static void |
|
|
1982 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1983 | \& { |
|
|
1984 | \& ev_check_stop (EV_A_ w); |
|
|
1985 | \& } |
|
|
1986 | .Ve |
|
|
1987 | .PP |
|
|
1988 | .Vb 4 |
|
|
1989 | \& ev_check check; |
|
|
1990 | \& ev_check_init (&check, check_cb); |
|
|
1991 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
1992 | \& ev_loop (EV_DEFAULT_ 0); |
|
|
1993 | .Ve |
|
|
1994 | .SH "EMBEDDING" |
|
|
1995 | .IX Header "EMBEDDING" |
|
|
1996 | Libev can (and often is) directly embedded into host |
|
|
1997 | applications. Examples of applications that embed it include the Deliantra |
|
|
1998 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
|
|
1999 | and rxvt\-unicode. |
|
|
2000 | .PP |
|
|
2001 | The goal is to enable you to just copy the neecssary files into your |
|
|
2002 | source directory without having to change even a single line in them, so |
|
|
2003 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
2004 | libev somewhere in your source tree). |
|
|
2005 | .Sh "\s-1FILESETS\s0" |
|
|
2006 | .IX Subsection "FILESETS" |
|
|
2007 | Depending on what features you need you need to include one or more sets of files |
|
|
2008 | in your app. |
|
|
2009 | .PP |
|
|
2010 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
|
|
2011 | .IX Subsection "CORE EVENT LOOP" |
|
|
2012 | .PP |
|
|
2013 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
|
|
2014 | configuration (no autoconf): |
|
|
2015 | .PP |
|
|
2016 | .Vb 2 |
|
|
2017 | \& #define EV_STANDALONE 1 |
|
|
2018 | \& #include "ev.c" |
|
|
2019 | .Ve |
|
|
2020 | .PP |
|
|
2021 | This will automatically include \fIev.h\fR, too, and should be done in a |
|
|
2022 | single C source file only to provide the function implementations. To use |
|
|
2023 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
|
|
2024 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
|
|
2025 | where you can put other configuration options): |
|
|
2026 | .PP |
|
|
2027 | .Vb 2 |
|
|
2028 | \& #define EV_STANDALONE 1 |
|
|
2029 | \& #include "ev.h" |
|
|
2030 | .Ve |
|
|
2031 | .PP |
|
|
2032 | Both header files and implementation files can be compiled with a \*(C+ |
|
|
2033 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
2034 | as a bug). |
|
|
2035 | .PP |
|
|
2036 | You need the following files in your source tree, or in a directory |
|
|
2037 | in your include path (e.g. in libev/ when using \-Ilibev): |
|
|
2038 | .PP |
|
|
2039 | .Vb 4 |
|
|
2040 | \& ev.h |
|
|
2041 | \& ev.c |
|
|
2042 | \& ev_vars.h |
|
|
2043 | \& ev_wrap.h |
|
|
2044 | .Ve |
|
|
2045 | .PP |
|
|
2046 | .Vb 1 |
|
|
2047 | \& ev_win32.c required on win32 platforms only |
|
|
2048 | .Ve |
|
|
2049 | .PP |
|
|
2050 | .Vb 5 |
|
|
2051 | \& ev_select.c only when select backend is enabled (which is by default) |
|
|
2052 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
2053 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
2054 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
2055 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
2056 | .Ve |
|
|
2057 | .PP |
|
|
2058 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
|
|
2059 | to compile this single file. |
|
|
2060 | .PP |
|
|
2061 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
|
|
2062 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
|
|
2063 | .PP |
|
|
2064 | To include the libevent compatibility \s-1API\s0, also include: |
|
|
2065 | .PP |
|
|
2066 | .Vb 1 |
|
|
2067 | \& #include "event.c" |
|
|
2068 | .Ve |
|
|
2069 | .PP |
|
|
2070 | in the file including \fIev.c\fR, and: |
|
|
2071 | .PP |
|
|
2072 | .Vb 1 |
|
|
2073 | \& #include "event.h" |
|
|
2074 | .Ve |
|
|
2075 | .PP |
|
|
2076 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
|
|
2077 | .PP |
|
|
2078 | You need the following additional files for this: |
|
|
2079 | .PP |
|
|
2080 | .Vb 2 |
|
|
2081 | \& event.h |
|
|
2082 | \& event.c |
|
|
2083 | .Ve |
|
|
2084 | .PP |
|
|
2085 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
|
|
2086 | .IX Subsection "AUTOCONF SUPPORT" |
|
|
2087 | .PP |
|
|
2088 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
|
|
2089 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
|
|
2090 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
|
|
2091 | include \fIconfig.h\fR and configure itself accordingly. |
|
|
2092 | .PP |
|
|
2093 | For this of course you need the m4 file: |
|
|
2094 | .PP |
|
|
2095 | .Vb 1 |
|
|
2096 | \& libev.m4 |
|
|
2097 | .Ve |
|
|
2098 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
|
|
2099 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
|
|
2100 | Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
2101 | before including any of its files. The default is not to build for multiplicity |
|
|
2102 | and only include the select backend. |
|
|
2103 | .IP "\s-1EV_STANDALONE\s0" 4 |
|
|
2104 | .IX Item "EV_STANDALONE" |
|
|
2105 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
|
|
2106 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
|
|
2107 | implementations for some libevent functions (such as logging, which is not |
|
|
2108 | supported). It will also not define any of the structs usually found in |
|
|
2109 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
|
|
2110 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
|
|
2111 | .IX Item "EV_USE_MONOTONIC" |
|
|
2112 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2113 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
2114 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
2115 | usually have to link against librt or something similar. Enabling it when |
|
|
2116 | the functionality isn't available is safe, though, althoguh you have |
|
|
2117 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
|
|
2118 | function is hiding in (often \fI\-lrt\fR). |
|
|
2119 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
|
|
2120 | .IX Item "EV_USE_REALTIME" |
|
|
2121 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2122 | realtime clock option at compiletime (and assume its availability at |
|
|
2123 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
2124 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
|
|
2125 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
|
|
2126 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2127 | .IP "\s-1EV_USE_SELECT\s0" 4 |
|
|
2128 | .IX Item "EV_USE_SELECT" |
|
|
2129 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
|
|
2130 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
|
|
2131 | other method takes over, select will be it. Otherwise the select backend |
|
|
2132 | will not be compiled in. |
|
|
2133 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
|
|
2134 | .IX Item "EV_SELECT_USE_FD_SET" |
|
|
2135 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
|
|
2136 | structure. This is useful if libev doesn't compile due to a missing |
|
|
2137 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on |
|
|
2138 | exotic systems. This usually limits the range of file descriptors to some |
|
|
2139 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
2140 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
|
|
2141 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
|
|
2142 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
|
|
2143 | .IX Item "EV_SELECT_IS_WINSOCKET" |
|
|
2144 | When defined to \f(CW1\fR, the select backend will assume that |
|
|
2145 | select/socket/connect etc. don't understand file descriptors but |
|
|
2146 | wants osf handles on win32 (this is the case when the select to |
|
|
2147 | be used is the winsock select). This means that it will call |
|
|
2148 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
|
|
2149 | it is assumed that all these functions actually work on fds, even |
|
|
2150 | on win32. Should not be defined on non\-win32 platforms. |
|
|
2151 | .IP "\s-1EV_USE_POLL\s0" 4 |
|
|
2152 | .IX Item "EV_USE_POLL" |
|
|
2153 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
|
|
2154 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
|
|
2155 | takes precedence over select. |
|
|
2156 | .IP "\s-1EV_USE_EPOLL\s0" 4 |
|
|
2157 | .IX Item "EV_USE_EPOLL" |
|
|
2158 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
2159 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
|
|
2160 | otherwise another method will be used as fallback. This is the |
|
|
2161 | preferred backend for GNU/Linux systems. |
|
|
2162 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
|
|
2163 | .IX Item "EV_USE_KQUEUE" |
|
|
2164 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
|
|
2165 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
|
|
2166 | otherwise another method will be used as fallback. This is the preferred |
|
|
2167 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
|
|
2168 | supports some types of fds correctly (the only platform we found that |
|
|
2169 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
2170 | not be used unless explicitly requested. The best way to use it is to find |
|
|
2171 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
2172 | kqueue loop. |
|
|
2173 | .IP "\s-1EV_USE_PORT\s0" 4 |
|
|
2174 | .IX Item "EV_USE_PORT" |
|
|
2175 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
|
|
2176 | 10 port style backend. Its availability will be detected at runtime, |
|
|
2177 | otherwise another method will be used as fallback. This is the preferred |
|
|
2178 | backend for Solaris 10 systems. |
|
|
2179 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
|
|
2180 | .IX Item "EV_USE_DEVPOLL" |
|
|
2181 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2182 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2183 | .IX Item "EV_USE_INOTIFY" |
|
|
2184 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2185 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2186 | be detected at runtime. |
|
|
2187 | .IP "\s-1EV_H\s0" 4 |
|
|
2188 | .IX Item "EV_H" |
|
|
2189 | The name of the \fIev.h\fR header file used to include it. The default if |
|
|
2190 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
|
|
2191 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
|
|
2192 | .IP "\s-1EV_CONFIG_H\s0" 4 |
|
|
2193 | .IX Item "EV_CONFIG_H" |
|
|
2194 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
|
|
2195 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
|
|
2196 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
|
|
2197 | .IP "\s-1EV_EVENT_H\s0" 4 |
|
|
2198 | .IX Item "EV_EVENT_H" |
|
|
2199 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
|
|
2200 | of how the \fIevent.h\fR header can be found. |
|
|
2201 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
|
|
2202 | .IX Item "EV_PROTOTYPES" |
|
|
2203 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
|
|
2204 | prototypes, but still define all the structs and other symbols. This is |
|
|
2205 | occasionally useful if you want to provide your own wrapper functions |
|
|
2206 | around libev functions. |
|
|
2207 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
|
|
2208 | .IX Item "EV_MULTIPLICITY" |
|
|
2209 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
|
|
2210 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
|
|
2211 | additional independent event loops. Otherwise there will be no support |
|
|
2212 | for multiple event loops and there is no first event loop pointer |
|
|
2213 | argument. Instead, all functions act on the single default loop. |
|
|
2214 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
|
|
2215 | .IX Item "EV_PERIODIC_ENABLE" |
|
|
2216 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2217 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2218 | code. |
|
|
2219 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2220 | .IX Item "EV_EMBED_ENABLE" |
|
|
2221 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2222 | defined to be \f(CW0\fR, then they are not. |
|
|
2223 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2224 | .IX Item "EV_STAT_ENABLE" |
|
|
2225 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2226 | defined to be \f(CW0\fR, then they are not. |
|
|
2227 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2228 | .IX Item "EV_FORK_ENABLE" |
|
|
2229 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2230 | defined to be \f(CW0\fR, then they are not. |
|
|
2231 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2232 | .IX Item "EV_MINIMAL" |
|
|
2233 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2234 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2235 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2236 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2237 | .IX Item "EV_PID_HASHSIZE" |
|
|
2238 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2239 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2240 | than enough. If you need to manage thousands of children you might want to |
|
|
2241 | increase this value (\fImust\fR be a power of two). |
|
|
2242 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2243 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2244 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2245 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2246 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2247 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2248 | two). |
|
|
2249 | .IP "\s-1EV_COMMON\s0" 4 |
|
|
2250 | .IX Item "EV_COMMON" |
|
|
2251 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
|
|
2252 | this macro to a something else you can include more and other types of |
|
|
2253 | members. You have to define it each time you include one of the files, |
|
|
2254 | though, and it must be identical each time. |
|
|
2255 | .Sp |
|
|
2256 | For example, the perl \s-1EV\s0 module uses something like this: |
|
|
2257 | .Sp |
|
|
2258 | .Vb 3 |
|
|
2259 | \& #define EV_COMMON \e |
|
|
2260 | \& SV *self; /* contains this struct */ \e |
|
|
2261 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
2262 | .Ve |
|
|
2263 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
|
|
2264 | .IX Item "EV_CB_DECLARE (type)" |
|
|
2265 | .PD 0 |
|
|
2266 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
|
|
2267 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
|
|
2268 | .IP "ev_set_cb (ev, cb)" 4 |
|
|
2269 | .IX Item "ev_set_cb (ev, cb)" |
|
|
2270 | .PD |
|
|
2271 | Can be used to change the callback member declaration in each watcher, |
|
|
2272 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
2273 | definition and a statement, respectively. See the \fIev.v\fR header file for |
|
|
2274 | their default definitions. One possible use for overriding these is to |
|
|
2275 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
|
|
2276 | method calls instead of plain function calls in \*(C+. |
|
|
2277 | .Sh "\s-1EXAMPLES\s0" |
|
|
2278 | .IX Subsection "EXAMPLES" |
|
|
2279 | For a real-world example of a program the includes libev |
|
|
2280 | verbatim, you can have a look at the \s-1EV\s0 perl module |
|
|
2281 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
|
|
2282 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
|
|
2283 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
|
|
2284 | will be compiled. It is pretty complex because it provides its own header |
|
|
2285 | file. |
|
|
2286 | .Sp |
|
|
2287 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
|
|
2288 | that everybody includes and which overrides some autoconf choices: |
|
|
2289 | .Sp |
|
|
2290 | .Vb 4 |
|
|
2291 | \& #define EV_USE_POLL 0 |
|
|
2292 | \& #define EV_MULTIPLICITY 0 |
|
|
2293 | \& #define EV_PERIODICS 0 |
|
|
2294 | \& #define EV_CONFIG_H <config.h> |
|
|
2295 | .Ve |
|
|
2296 | .Sp |
|
|
2297 | .Vb 1 |
|
|
2298 | \& #include "ev++.h" |
|
|
2299 | .Ve |
|
|
2300 | .Sp |
|
|
2301 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
|
|
2302 | .Sp |
|
|
2303 | .Vb 2 |
|
|
2304 | \& #include "ev_cpp.h" |
|
|
2305 | \& #include "ev.c" |
|
|
2306 | .Ve |
|
|
2307 | .SH "COMPLEXITIES" |
|
|
2308 | .IX Header "COMPLEXITIES" |
|
|
2309 | In this section the complexities of (many of) the algorithms used inside |
|
|
2310 | libev will be explained. For complexity discussions about backends see the |
|
|
2311 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2312 | .RS 4 |
|
|
2313 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
|
|
2314 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
|
|
2315 | .PD 0 |
|
|
2316 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
|
|
2317 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2318 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2319 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2320 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
|
|
2321 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2322 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
|
|
2323 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2324 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
|
|
2325 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2326 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2327 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2328 | .IP "Activating one watcher: O(1)" 4 |
|
|
2329 | .IX Item "Activating one watcher: O(1)" |
|
|
2330 | .RE |
|
|
2331 | .RS 4 |
|
|
2332 | .PD |
1350 | .SH "AUTHOR" |
2333 | .SH "AUTHOR" |
1351 | .IX Header "AUTHOR" |
2334 | .IX Header "AUTHOR" |
1352 | Marc Lehmann <libev@schmorp.de>. |
2335 | Marc Lehmann <libev@schmorp.de>. |