… | |
… | |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | #include <ev.h> |
7 | #include <ev.h> |
8 | |
8 | |
|
|
9 | =head1 EXAMPLE PROGRAM |
|
|
10 | |
|
|
11 | #include <ev.h> |
|
|
12 | |
|
|
13 | ev_io stdin_watcher; |
|
|
14 | ev_timer timeout_watcher; |
|
|
15 | |
|
|
16 | /* called when data readable on stdin */ |
|
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17 | static void |
|
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18 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
|
|
19 | { |
|
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20 | /* puts ("stdin ready"); */ |
|
|
21 | ev_io_stop (EV_A_ w); /* just a syntax example */ |
|
|
22 | ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
|
|
23 | } |
|
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24 | |
|
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25 | static void |
|
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26 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
|
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27 | { |
|
|
28 | /* puts ("timeout"); */ |
|
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29 | ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
|
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30 | } |
|
|
31 | |
|
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32 | int |
|
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33 | main (void) |
|
|
34 | { |
|
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35 | struct ev_loop *loop = ev_default_loop (0); |
|
|
36 | |
|
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37 | /* initialise an io watcher, then start it */ |
|
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38 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
|
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39 | ev_io_start (loop, &stdin_watcher); |
|
|
40 | |
|
|
41 | /* simple non-repeating 5.5 second timeout */ |
|
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42 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
|
|
43 | ev_timer_start (loop, &timeout_watcher); |
|
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44 | |
|
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45 | /* loop till timeout or data ready */ |
|
|
46 | ev_loop (loop, 0); |
|
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47 | |
|
|
48 | return 0; |
|
|
49 | } |
|
|
50 | |
9 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
|
|
52 | |
|
|
53 | The newest version of this document is also available as a html-formatted |
|
|
54 | web page you might find easier to navigate when reading it for the first |
|
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55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
10 | |
56 | |
11 | Libev is an event loop: you register interest in certain events (such as a |
57 | Libev is an event loop: you register interest in certain events (such as a |
12 | file descriptor being readable or a timeout occuring), and it will manage |
58 | file descriptor being readable or a timeout occuring), and it will manage |
13 | these event sources and provide your program with events. |
59 | these event sources and provide your program with events. |
14 | |
60 | |
… | |
… | |
21 | details of the event, and then hand it over to libev by I<starting> the |
67 | details of the event, and then hand it over to libev by I<starting> the |
22 | watcher. |
68 | watcher. |
23 | |
69 | |
24 | =head1 FEATURES |
70 | =head1 FEATURES |
25 | |
71 | |
26 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
72 | Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the |
27 | kqueue mechanisms for file descriptor events, relative timers, absolute |
73 | BSD-specific C<kqueue> and the Solaris-specific event port mechanisms |
28 | timers with customised rescheduling, signal events, process status change |
74 | for file descriptor events (C<ev_io>), the Linux C<inotify> interface |
29 | events (related to SIGCHLD), and event watchers dealing with the event |
75 | (for C<ev_stat>), relative timers (C<ev_timer>), absolute timers |
30 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
76 | with customised rescheduling (C<ev_periodic>), synchronous signals |
|
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77 | (C<ev_signal>), process status change events (C<ev_child>), and event |
|
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78 | watchers dealing with the event loop mechanism itself (C<ev_idle>, |
|
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79 | C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as |
|
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80 | file watchers (C<ev_stat>) and even limited support for fork events |
|
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81 | (C<ev_fork>). |
|
|
82 | |
|
|
83 | It also is quite fast (see this |
31 | fast (see this L<benchmark|http://libev.schmorp.de/bench.html> comparing |
84 | L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent |
32 | it to libevent for example). |
85 | for example). |
33 | |
86 | |
34 | =head1 CONVENTIONS |
87 | =head1 CONVENTIONS |
35 | |
88 | |
36 | Libev is very configurable. In this manual the default configuration |
89 | Libev is very configurable. In this manual the default configuration will |
37 | will be described, which supports multiple event loops. For more info |
90 | be described, which supports multiple event loops. For more info about |
38 | about various configuration options please have a look at the file |
91 | various configuration options please have a look at B<EMBED> section in |
39 | F<README.embed> in the libev distribution. If libev was configured without |
92 | this manual. If libev was configured without support for multiple event |
40 | support for multiple event loops, then all functions taking an initial |
93 | loops, then all functions taking an initial argument of name C<loop> |
41 | argument of name C<loop> (which is always of type C<struct ev_loop *>) |
94 | (which is always of type C<struct ev_loop *>) will not have this argument. |
42 | will not have this argument. |
|
|
43 | |
95 | |
44 | =head1 TIME REPRESENTATION |
96 | =head1 TIME REPRESENTATION |
45 | |
97 | |
46 | Libev represents time as a single floating point number, representing the |
98 | Libev represents time as a single floating point number, representing the |
47 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
99 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
… | |
… | |
76 | Usually, it's a good idea to terminate if the major versions mismatch, |
128 | Usually, it's a good idea to terminate if the major versions mismatch, |
77 | as this indicates an incompatible change. Minor versions are usually |
129 | as this indicates an incompatible change. Minor versions are usually |
78 | compatible to older versions, so a larger minor version alone is usually |
130 | compatible to older versions, so a larger minor version alone is usually |
79 | not a problem. |
131 | not a problem. |
80 | |
132 | |
81 | Example: make sure we haven't accidentally been linked against the wrong |
133 | Example: Make sure we haven't accidentally been linked against the wrong |
82 | version: |
134 | version. |
83 | |
135 | |
84 | assert (("libev version mismatch", |
136 | assert (("libev version mismatch", |
85 | ev_version_major () == EV_VERSION_MAJOR |
137 | ev_version_major () == EV_VERSION_MAJOR |
86 | && ev_version_minor () >= EV_VERSION_MINOR)); |
138 | && ev_version_minor () >= EV_VERSION_MINOR)); |
87 | |
139 | |
… | |
… | |
115 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
167 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
116 | recommended ones. |
168 | recommended ones. |
117 | |
169 | |
118 | See the description of C<ev_embed> watchers for more info. |
170 | See the description of C<ev_embed> watchers for more info. |
119 | |
171 | |
120 | =item ev_set_allocator (void *(*cb)(void *ptr, size_t size)) |
172 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
121 | |
173 | |
122 | Sets the allocation function to use (the prototype and semantics are |
174 | Sets the allocation function to use (the prototype is similar - the |
123 | identical to the realloc C function). It is used to allocate and free |
175 | semantics is identical - to the realloc C function). It is used to |
124 | memory (no surprises here). If it returns zero when memory needs to be |
176 | allocate and free memory (no surprises here). If it returns zero when |
125 | allocated, the library might abort or take some potentially destructive |
177 | memory needs to be allocated, the library might abort or take some |
126 | action. The default is your system realloc function. |
178 | potentially destructive action. The default is your system realloc |
|
|
179 | function. |
127 | |
180 | |
128 | You could override this function in high-availability programs to, say, |
181 | You could override this function in high-availability programs to, say, |
129 | free some memory if it cannot allocate memory, to use a special allocator, |
182 | free some memory if it cannot allocate memory, to use a special allocator, |
130 | or even to sleep a while and retry until some memory is available. |
183 | or even to sleep a while and retry until some memory is available. |
131 | |
184 | |
132 | Example: replace the libev allocator with one that waits a bit and then |
185 | Example: Replace the libev allocator with one that waits a bit and then |
133 | retries: better than mine). |
186 | retries). |
134 | |
187 | |
135 | static void * |
188 | static void * |
136 | persistent_realloc (void *ptr, size_t size) |
189 | persistent_realloc (void *ptr, size_t size) |
137 | { |
190 | { |
138 | for (;;) |
191 | for (;;) |
… | |
… | |
157 | callback is set, then libev will expect it to remedy the sitution, no |
210 | callback is set, then libev will expect it to remedy the sitution, no |
158 | matter what, when it returns. That is, libev will generally retry the |
211 | matter what, when it returns. That is, libev will generally retry the |
159 | requested operation, or, if the condition doesn't go away, do bad stuff |
212 | requested operation, or, if the condition doesn't go away, do bad stuff |
160 | (such as abort). |
213 | (such as abort). |
161 | |
214 | |
162 | Example: do the same thing as libev does internally: |
215 | Example: This is basically the same thing that libev does internally, too. |
163 | |
216 | |
164 | static void |
217 | static void |
165 | fatal_error (const char *msg) |
218 | fatal_error (const char *msg) |
166 | { |
219 | { |
167 | perror (msg); |
220 | perror (msg); |
… | |
… | |
217 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
270 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
218 | override the flags completely if it is found in the environment. This is |
271 | override the flags completely if it is found in the environment. This is |
219 | useful to try out specific backends to test their performance, or to work |
272 | useful to try out specific backends to test their performance, or to work |
220 | around bugs. |
273 | around bugs. |
221 | |
274 | |
|
|
275 | =item C<EVFLAG_FORKCHECK> |
|
|
276 | |
|
|
277 | Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after |
|
|
278 | a fork, you can also make libev check for a fork in each iteration by |
|
|
279 | enabling this flag. |
|
|
280 | |
|
|
281 | This works by calling C<getpid ()> on every iteration of the loop, |
|
|
282 | and thus this might slow down your event loop if you do a lot of loop |
|
|
283 | iterations and little real work, but is usually not noticeable (on my |
|
|
284 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
|
|
285 | without a syscall and thus I<very> fast, but my Linux system also has |
|
|
286 | C<pthread_atfork> which is even faster). |
|
|
287 | |
|
|
288 | The big advantage of this flag is that you can forget about fork (and |
|
|
289 | forget about forgetting to tell libev about forking) when you use this |
|
|
290 | flag. |
|
|
291 | |
|
|
292 | This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS> |
|
|
293 | environment variable. |
|
|
294 | |
222 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
295 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
223 | |
296 | |
224 | This is your standard select(2) backend. Not I<completely> standard, as |
297 | This is your standard select(2) backend. Not I<completely> standard, as |
225 | libev tries to roll its own fd_set with no limits on the number of fds, |
298 | libev tries to roll its own fd_set with no limits on the number of fds, |
226 | but if that fails, expect a fairly low limit on the number of fds when |
299 | but if that fails, expect a fairly low limit on the number of fds when |
… | |
… | |
313 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
386 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
314 | always distinct from the default loop. Unlike the default loop, it cannot |
387 | always distinct from the default loop. Unlike the default loop, it cannot |
315 | handle signal and child watchers, and attempts to do so will be greeted by |
388 | handle signal and child watchers, and attempts to do so will be greeted by |
316 | undefined behaviour (or a failed assertion if assertions are enabled). |
389 | undefined behaviour (or a failed assertion if assertions are enabled). |
317 | |
390 | |
318 | Example: try to create a event loop that uses epoll and nothing else. |
391 | Example: Try to create a event loop that uses epoll and nothing else. |
319 | |
392 | |
320 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
393 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
321 | if (!epoller) |
394 | if (!epoller) |
322 | fatal ("no epoll found here, maybe it hides under your chair"); |
395 | fatal ("no epoll found here, maybe it hides under your chair"); |
323 | |
396 | |
… | |
… | |
360 | =item ev_loop_fork (loop) |
433 | =item ev_loop_fork (loop) |
361 | |
434 | |
362 | Like C<ev_default_fork>, but acts on an event loop created by |
435 | Like C<ev_default_fork>, but acts on an event loop created by |
363 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
436 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
364 | after fork, and how you do this is entirely your own problem. |
437 | after fork, and how you do this is entirely your own problem. |
|
|
438 | |
|
|
439 | =item unsigned int ev_loop_count (loop) |
|
|
440 | |
|
|
441 | Returns the count of loop iterations for the loop, which is identical to |
|
|
442 | the number of times libev did poll for new events. It starts at C<0> and |
|
|
443 | happily wraps around with enough iterations. |
|
|
444 | |
|
|
445 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
446 | "ticks" the number of loop iterations), as it roughly corresponds with |
|
|
447 | C<ev_prepare> and C<ev_check> calls. |
365 | |
448 | |
366 | =item unsigned int ev_backend (loop) |
449 | =item unsigned int ev_backend (loop) |
367 | |
450 | |
368 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
451 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
369 | use. |
452 | use. |
… | |
… | |
422 | Signals and child watchers are implemented as I/O watchers, and will |
505 | Signals and child watchers are implemented as I/O watchers, and will |
423 | be handled here by queueing them when their watcher gets executed. |
506 | be handled here by queueing them when their watcher gets executed. |
424 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
507 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
425 | were used, return, otherwise continue with step *. |
508 | were used, return, otherwise continue with step *. |
426 | |
509 | |
427 | Example: queue some jobs and then loop until no events are outsanding |
510 | Example: Queue some jobs and then loop until no events are outsanding |
428 | anymore. |
511 | anymore. |
429 | |
512 | |
430 | ... queue jobs here, make sure they register event watchers as long |
513 | ... queue jobs here, make sure they register event watchers as long |
431 | ... as they still have work to do (even an idle watcher will do..) |
514 | ... as they still have work to do (even an idle watcher will do..) |
432 | ev_loop (my_loop, 0); |
515 | ev_loop (my_loop, 0); |
… | |
… | |
452 | visible to the libev user and should not keep C<ev_loop> from exiting if |
535 | visible to the libev user and should not keep C<ev_loop> from exiting if |
453 | no event watchers registered by it are active. It is also an excellent |
536 | no event watchers registered by it are active. It is also an excellent |
454 | way to do this for generic recurring timers or from within third-party |
537 | way to do this for generic recurring timers or from within third-party |
455 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
538 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
456 | |
539 | |
457 | Example: create a signal watcher, but keep it from keeping C<ev_loop> |
540 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
458 | running when nothing else is active. |
541 | running when nothing else is active. |
459 | |
542 | |
460 | struct dv_signal exitsig; |
543 | struct ev_signal exitsig; |
461 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
544 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
462 | ev_signal_start (myloop, &exitsig); |
545 | ev_signal_start (loop, &exitsig); |
463 | evf_unref (myloop); |
546 | evf_unref (loop); |
464 | |
547 | |
465 | Example: for some weird reason, unregister the above signal handler again. |
548 | Example: For some weird reason, unregister the above signal handler again. |
466 | |
549 | |
467 | ev_ref (myloop); |
550 | ev_ref (loop); |
468 | ev_signal_stop (myloop, &exitsig); |
551 | ev_signal_stop (loop, &exitsig); |
469 | |
552 | |
470 | =back |
553 | =back |
471 | |
554 | |
472 | |
555 | |
473 | =head1 ANATOMY OF A WATCHER |
556 | =head1 ANATOMY OF A WATCHER |
… | |
… | |
656 | events but its callback has not yet been invoked). As long as a watcher |
739 | events but its callback has not yet been invoked). As long as a watcher |
657 | is pending (but not active) you must not call an init function on it (but |
740 | is pending (but not active) you must not call an init function on it (but |
658 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
741 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
659 | libev (e.g. you cnanot C<free ()> it). |
742 | libev (e.g. you cnanot C<free ()> it). |
660 | |
743 | |
661 | =item callback = ev_cb (ev_TYPE *watcher) |
744 | =item callback ev_cb (ev_TYPE *watcher) |
662 | |
745 | |
663 | Returns the callback currently set on the watcher. |
746 | Returns the callback currently set on the watcher. |
664 | |
747 | |
665 | =item ev_cb_set (ev_TYPE *watcher, callback) |
748 | =item ev_cb_set (ev_TYPE *watcher, callback) |
666 | |
749 | |
667 | Change the callback. You can change the callback at virtually any time |
750 | Change the callback. You can change the callback at virtually any time |
668 | (modulo threads). |
751 | (modulo threads). |
|
|
752 | |
|
|
753 | =item ev_set_priority (ev_TYPE *watcher, priority) |
|
|
754 | |
|
|
755 | =item int ev_priority (ev_TYPE *watcher) |
|
|
756 | |
|
|
757 | Set and query the priority of the watcher. The priority is a small |
|
|
758 | integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> |
|
|
759 | (default: C<-2>). Pending watchers with higher priority will be invoked |
|
|
760 | before watchers with lower priority, but priority will not keep watchers |
|
|
761 | from being executed (except for C<ev_idle> watchers). |
|
|
762 | |
|
|
763 | This means that priorities are I<only> used for ordering callback |
|
|
764 | invocation after new events have been received. This is useful, for |
|
|
765 | example, to reduce latency after idling, or more often, to bind two |
|
|
766 | watchers on the same event and make sure one is called first. |
|
|
767 | |
|
|
768 | If you need to suppress invocation when higher priority events are pending |
|
|
769 | you need to look at C<ev_idle> watchers, which provide this functionality. |
|
|
770 | |
|
|
771 | The default priority used by watchers when no priority has been set is |
|
|
772 | always C<0>, which is supposed to not be too high and not be too low :). |
|
|
773 | |
|
|
774 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
|
|
775 | fine, as long as you do not mind that the priority value you query might |
|
|
776 | or might not have been adjusted to be within valid range. |
669 | |
777 | |
670 | =back |
778 | =back |
671 | |
779 | |
672 | |
780 | |
673 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
781 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
694 | { |
802 | { |
695 | struct my_io *w = (struct my_io *)w_; |
803 | struct my_io *w = (struct my_io *)w_; |
696 | ... |
804 | ... |
697 | } |
805 | } |
698 | |
806 | |
699 | More interesting and less C-conformant ways of catsing your callback type |
807 | More interesting and less C-conformant ways of casting your callback type |
700 | have been omitted.... |
808 | instead have been omitted. |
|
|
809 | |
|
|
810 | Another common scenario is having some data structure with multiple |
|
|
811 | watchers: |
|
|
812 | |
|
|
813 | struct my_biggy |
|
|
814 | { |
|
|
815 | int some_data; |
|
|
816 | ev_timer t1; |
|
|
817 | ev_timer t2; |
|
|
818 | } |
|
|
819 | |
|
|
820 | In this case getting the pointer to C<my_biggy> is a bit more complicated, |
|
|
821 | you need to use C<offsetof>: |
|
|
822 | |
|
|
823 | #include <stddef.h> |
|
|
824 | |
|
|
825 | static void |
|
|
826 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
827 | { |
|
|
828 | struct my_biggy big = (struct my_biggy * |
|
|
829 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
830 | } |
|
|
831 | |
|
|
832 | static void |
|
|
833 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
834 | { |
|
|
835 | struct my_biggy big = (struct my_biggy * |
|
|
836 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
837 | } |
701 | |
838 | |
702 | |
839 | |
703 | =head1 WATCHER TYPES |
840 | =head1 WATCHER TYPES |
704 | |
841 | |
705 | This section describes each watcher in detail, but will not repeat |
842 | This section describes each watcher in detail, but will not repeat |
… | |
… | |
750 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
887 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
751 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
888 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
752 | |
889 | |
753 | If you cannot run the fd in non-blocking mode (for example you should not |
890 | If you cannot run the fd in non-blocking mode (for example you should not |
754 | play around with an Xlib connection), then you have to seperately re-test |
891 | play around with an Xlib connection), then you have to seperately re-test |
755 | wether a file descriptor is really ready with a known-to-be good interface |
892 | whether a file descriptor is really ready with a known-to-be good interface |
756 | such as poll (fortunately in our Xlib example, Xlib already does this on |
893 | such as poll (fortunately in our Xlib example, Xlib already does this on |
757 | its own, so its quite safe to use). |
894 | its own, so its quite safe to use). |
758 | |
895 | |
759 | =over 4 |
896 | =over 4 |
760 | |
897 | |
… | |
… | |
774 | |
911 | |
775 | The events being watched. |
912 | The events being watched. |
776 | |
913 | |
777 | =back |
914 | =back |
778 | |
915 | |
779 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
916 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
780 | readable, but only once. Since it is likely line-buffered, you could |
917 | readable, but only once. Since it is likely line-buffered, you could |
781 | attempt to read a whole line in the callback: |
918 | attempt to read a whole line in the callback. |
782 | |
919 | |
783 | static void |
920 | static void |
784 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
921 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
785 | { |
922 | { |
786 | ev_io_stop (loop, w); |
923 | ev_io_stop (loop, w); |
… | |
… | |
838 | =item ev_timer_again (loop) |
975 | =item ev_timer_again (loop) |
839 | |
976 | |
840 | This will act as if the timer timed out and restart it again if it is |
977 | This will act as if the timer timed out and restart it again if it is |
841 | repeating. The exact semantics are: |
978 | repeating. The exact semantics are: |
842 | |
979 | |
|
|
980 | If the timer is pending, its pending status is cleared. |
|
|
981 | |
843 | If the timer is started but nonrepeating, stop it. |
982 | If the timer is started but nonrepeating, stop it (as if it timed out). |
844 | |
983 | |
845 | If the timer is repeating, either start it if necessary (with the repeat |
984 | If the timer is repeating, either start it if necessary (with the |
846 | value), or reset the running timer to the repeat value. |
985 | C<repeat> value), or reset the running timer to the C<repeat> value. |
847 | |
986 | |
848 | This sounds a bit complicated, but here is a useful and typical |
987 | This sounds a bit complicated, but here is a useful and typical |
849 | example: Imagine you have a tcp connection and you want a so-called |
988 | example: Imagine you have a tcp connection and you want a so-called idle |
850 | idle timeout, that is, you want to be called when there have been, |
989 | timeout, that is, you want to be called when there have been, say, 60 |
851 | say, 60 seconds of inactivity on the socket. The easiest way to do |
990 | seconds of inactivity on the socket. The easiest way to do this is to |
852 | this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling |
991 | configure an C<ev_timer> with a C<repeat> value of C<60> and then call |
853 | C<ev_timer_again> each time you successfully read or write some data. If |
992 | C<ev_timer_again> each time you successfully read or write some data. If |
854 | you go into an idle state where you do not expect data to travel on the |
993 | you go into an idle state where you do not expect data to travel on the |
855 | socket, you can stop the timer, and again will automatically restart it if |
994 | socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will |
856 | need be. |
995 | automatically restart it if need be. |
857 | |
996 | |
858 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
997 | That means you can ignore the C<after> value and C<ev_timer_start> |
859 | and only ever use the C<repeat> value: |
998 | altogether and only ever use the C<repeat> value and C<ev_timer_again>: |
860 | |
999 | |
861 | ev_timer_init (timer, callback, 0., 5.); |
1000 | ev_timer_init (timer, callback, 0., 5.); |
862 | ev_timer_again (loop, timer); |
1001 | ev_timer_again (loop, timer); |
863 | ... |
1002 | ... |
864 | timer->again = 17.; |
1003 | timer->again = 17.; |
865 | ev_timer_again (loop, timer); |
1004 | ev_timer_again (loop, timer); |
866 | ... |
1005 | ... |
867 | timer->again = 10.; |
1006 | timer->again = 10.; |
868 | ev_timer_again (loop, timer); |
1007 | ev_timer_again (loop, timer); |
869 | |
1008 | |
870 | This is more efficient then stopping/starting the timer eahc time you want |
1009 | This is more slightly efficient then stopping/starting the timer each time |
871 | to modify its timeout value. |
1010 | you want to modify its timeout value. |
872 | |
1011 | |
873 | =item ev_tstamp repeat [read-write] |
1012 | =item ev_tstamp repeat [read-write] |
874 | |
1013 | |
875 | The current C<repeat> value. Will be used each time the watcher times out |
1014 | The current C<repeat> value. Will be used each time the watcher times out |
876 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1015 | or C<ev_timer_again> is called and determines the next timeout (if any), |
877 | which is also when any modifications are taken into account. |
1016 | which is also when any modifications are taken into account. |
878 | |
1017 | |
879 | =back |
1018 | =back |
880 | |
1019 | |
881 | Example: create a timer that fires after 60 seconds. |
1020 | Example: Create a timer that fires after 60 seconds. |
882 | |
1021 | |
883 | static void |
1022 | static void |
884 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1023 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
885 | { |
1024 | { |
886 | .. one minute over, w is actually stopped right here |
1025 | .. one minute over, w is actually stopped right here |
… | |
… | |
888 | |
1027 | |
889 | struct ev_timer mytimer; |
1028 | struct ev_timer mytimer; |
890 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1029 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
891 | ev_timer_start (loop, &mytimer); |
1030 | ev_timer_start (loop, &mytimer); |
892 | |
1031 | |
893 | Example: create a timeout timer that times out after 10 seconds of |
1032 | Example: Create a timeout timer that times out after 10 seconds of |
894 | inactivity. |
1033 | inactivity. |
895 | |
1034 | |
896 | static void |
1035 | static void |
897 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1036 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
898 | { |
1037 | { |
… | |
… | |
1023 | switched off. Can be changed any time, but changes only take effect when |
1162 | switched off. Can be changed any time, but changes only take effect when |
1024 | the periodic timer fires or C<ev_periodic_again> is being called. |
1163 | the periodic timer fires or C<ev_periodic_again> is being called. |
1025 | |
1164 | |
1026 | =back |
1165 | =back |
1027 | |
1166 | |
1028 | Example: call a callback every hour, or, more precisely, whenever the |
1167 | Example: Call a callback every hour, or, more precisely, whenever the |
1029 | system clock is divisible by 3600. The callback invocation times have |
1168 | system clock is divisible by 3600. The callback invocation times have |
1030 | potentially a lot of jittering, but good long-term stability. |
1169 | potentially a lot of jittering, but good long-term stability. |
1031 | |
1170 | |
1032 | static void |
1171 | static void |
1033 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1172 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
1037 | |
1176 | |
1038 | struct ev_periodic hourly_tick; |
1177 | struct ev_periodic hourly_tick; |
1039 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1178 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1040 | ev_periodic_start (loop, &hourly_tick); |
1179 | ev_periodic_start (loop, &hourly_tick); |
1041 | |
1180 | |
1042 | Example: the same as above, but use a reschedule callback to do it: |
1181 | Example: The same as above, but use a reschedule callback to do it: |
1043 | |
1182 | |
1044 | #include <math.h> |
1183 | #include <math.h> |
1045 | |
1184 | |
1046 | static ev_tstamp |
1185 | static ev_tstamp |
1047 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1186 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
1049 | return fmod (now, 3600.) + 3600.; |
1188 | return fmod (now, 3600.) + 3600.; |
1050 | } |
1189 | } |
1051 | |
1190 | |
1052 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1191 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1053 | |
1192 | |
1054 | Example: call a callback every hour, starting now: |
1193 | Example: Call a callback every hour, starting now: |
1055 | |
1194 | |
1056 | struct ev_periodic hourly_tick; |
1195 | struct ev_periodic hourly_tick; |
1057 | ev_periodic_init (&hourly_tick, clock_cb, |
1196 | ev_periodic_init (&hourly_tick, clock_cb, |
1058 | fmod (ev_now (loop), 3600.), 3600., 0); |
1197 | fmod (ev_now (loop), 3600.), 3600., 0); |
1059 | ev_periodic_start (loop, &hourly_tick); |
1198 | ev_periodic_start (loop, &hourly_tick); |
… | |
… | |
1120 | The process exit/trace status caused by C<rpid> (see your systems |
1259 | The process exit/trace status caused by C<rpid> (see your systems |
1121 | C<waitpid> and C<sys/wait.h> documentation for details). |
1260 | C<waitpid> and C<sys/wait.h> documentation for details). |
1122 | |
1261 | |
1123 | =back |
1262 | =back |
1124 | |
1263 | |
1125 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1264 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1126 | |
1265 | |
1127 | static void |
1266 | static void |
1128 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1267 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1129 | { |
1268 | { |
1130 | ev_unloop (loop, EVUNLOOP_ALL); |
1269 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
1145 | not exist" is a status change like any other. The condition "path does |
1284 | not exist" is a status change like any other. The condition "path does |
1146 | not exist" is signified by the C<st_nlink> field being zero (which is |
1285 | not exist" is signified by the C<st_nlink> field being zero (which is |
1147 | otherwise always forced to be at least one) and all the other fields of |
1286 | otherwise always forced to be at least one) and all the other fields of |
1148 | the stat buffer having unspecified contents. |
1287 | the stat buffer having unspecified contents. |
1149 | |
1288 | |
|
|
1289 | The path I<should> be absolute and I<must not> end in a slash. If it is |
|
|
1290 | relative and your working directory changes, the behaviour is undefined. |
|
|
1291 | |
1150 | Since there is no standard to do this, the portable implementation simply |
1292 | Since there is no standard to do this, the portable implementation simply |
1151 | calls C<stat (2)> regulalry on the path to see if it changed somehow. You |
1293 | calls C<stat (2)> regularly on the path to see if it changed somehow. You |
1152 | can specify a recommended polling interval for this case. If you specify |
1294 | can specify a recommended polling interval for this case. If you specify |
1153 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1295 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1154 | unspecified default> value will be used (which you can expect to be around |
1296 | unspecified default> value will be used (which you can expect to be around |
1155 | five seconds, although this might change dynamically). Libev will also |
1297 | five seconds, although this might change dynamically). Libev will also |
1156 | impose a minimum interval which is currently around C<0.1>, but thats |
1298 | impose a minimum interval which is currently around C<0.1>, but thats |
… | |
… | |
1158 | |
1300 | |
1159 | This watcher type is not meant for massive numbers of stat watchers, |
1301 | This watcher type is not meant for massive numbers of stat watchers, |
1160 | as even with OS-supported change notifications, this can be |
1302 | as even with OS-supported change notifications, this can be |
1161 | resource-intensive. |
1303 | resource-intensive. |
1162 | |
1304 | |
1163 | At the time of this writing, no specific OS backends are implemented, but |
1305 | At the time of this writing, only the Linux inotify interface is |
1164 | if demand increases, at least a kqueue and inotify backend will be added. |
1306 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1307 | reader). Inotify will be used to give hints only and should not change the |
|
|
1308 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
|
|
1309 | to fall back to regular polling again even with inotify, but changes are |
|
|
1310 | usually detected immediately, and if the file exists there will be no |
|
|
1311 | polling. |
1165 | |
1312 | |
1166 | =over 4 |
1313 | =over 4 |
1167 | |
1314 | |
1168 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1315 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1169 | |
1316 | |
… | |
… | |
1233 | ev_stat_start (loop, &passwd); |
1380 | ev_stat_start (loop, &passwd); |
1234 | |
1381 | |
1235 | |
1382 | |
1236 | =head2 C<ev_idle> - when you've got nothing better to do... |
1383 | =head2 C<ev_idle> - when you've got nothing better to do... |
1237 | |
1384 | |
1238 | Idle watchers trigger events when there are no other events are pending |
1385 | Idle watchers trigger events when no other events of the same or higher |
1239 | (prepare, check and other idle watchers do not count). That is, as long |
1386 | priority are pending (prepare, check and other idle watchers do not |
1240 | as your process is busy handling sockets or timeouts (or even signals, |
1387 | count). |
1241 | imagine) it will not be triggered. But when your process is idle all idle |
1388 | |
1242 | watchers are being called again and again, once per event loop iteration - |
1389 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1390 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1391 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1392 | are pending), the idle watchers are being called once per event loop |
1243 | until stopped, that is, or your process receives more events and becomes |
1393 | iteration - until stopped, that is, or your process receives more events |
1244 | busy. |
1394 | and becomes busy again with higher priority stuff. |
1245 | |
1395 | |
1246 | The most noteworthy effect is that as long as any idle watchers are |
1396 | The most noteworthy effect is that as long as any idle watchers are |
1247 | active, the process will not block when waiting for new events. |
1397 | active, the process will not block when waiting for new events. |
1248 | |
1398 | |
1249 | Apart from keeping your process non-blocking (which is a useful |
1399 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1259 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1409 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1260 | believe me. |
1410 | believe me. |
1261 | |
1411 | |
1262 | =back |
1412 | =back |
1263 | |
1413 | |
1264 | Example: dynamically allocate an C<ev_idle>, start it, and in the |
1414 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1265 | callback, free it. Alos, use no error checking, as usual. |
1415 | callback, free it. Also, use no error checking, as usual. |
1266 | |
1416 | |
1267 | static void |
1417 | static void |
1268 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1418 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1269 | { |
1419 | { |
1270 | free (w); |
1420 | free (w); |
… | |
… | |
1349 | |
1499 | |
1350 | // create io watchers for each fd and a timer before blocking |
1500 | // create io watchers for each fd and a timer before blocking |
1351 | static void |
1501 | static void |
1352 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1502 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1353 | { |
1503 | { |
1354 | int timeout = 3600000;truct pollfd fds [nfd]; |
1504 | int timeout = 3600000; |
|
|
1505 | struct pollfd fds [nfd]; |
1355 | // actual code will need to loop here and realloc etc. |
1506 | // actual code will need to loop here and realloc etc. |
1356 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1507 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1357 | |
1508 | |
1358 | /* the callback is illegal, but won't be called as we stop during check */ |
1509 | /* the callback is illegal, but won't be called as we stop during check */ |
1359 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1510 | ev_timer_init (&tw, 0, timeout * 1e-3); |
… | |
… | |
1697 | |
1848 | |
1698 | |
1849 | |
1699 | =head1 MACRO MAGIC |
1850 | =head1 MACRO MAGIC |
1700 | |
1851 | |
1701 | Libev can be compiled with a variety of options, the most fundemantal is |
1852 | Libev can be compiled with a variety of options, the most fundemantal is |
1702 | C<EV_MULTIPLICITY>. This option determines wether (most) functions and |
1853 | C<EV_MULTIPLICITY>. This option determines whether (most) functions and |
1703 | callbacks have an initial C<struct ev_loop *> argument. |
1854 | callbacks have an initial C<struct ev_loop *> argument. |
1704 | |
1855 | |
1705 | To make it easier to write programs that cope with either variant, the |
1856 | To make it easier to write programs that cope with either variant, the |
1706 | following macros are defined: |
1857 | following macros are defined: |
1707 | |
1858 | |
… | |
… | |
1740 | Similar to the other two macros, this gives you the value of the default |
1891 | Similar to the other two macros, this gives you the value of the default |
1741 | loop, if multiple loops are supported ("ev loop default"). |
1892 | loop, if multiple loops are supported ("ev loop default"). |
1742 | |
1893 | |
1743 | =back |
1894 | =back |
1744 | |
1895 | |
1745 | Example: Declare and initialise a check watcher, working regardless of |
1896 | Example: Declare and initialise a check watcher, utilising the above |
1746 | wether multiple loops are supported or not. |
1897 | macros so it will work regardless of whether multiple loops are supported |
|
|
1898 | or not. |
1747 | |
1899 | |
1748 | static void |
1900 | static void |
1749 | check_cb (EV_P_ ev_timer *w, int revents) |
1901 | check_cb (EV_P_ ev_timer *w, int revents) |
1750 | { |
1902 | { |
1751 | ev_check_stop (EV_A_ w); |
1903 | ev_check_stop (EV_A_ w); |
… | |
… | |
1754 | ev_check check; |
1906 | ev_check check; |
1755 | ev_check_init (&check, check_cb); |
1907 | ev_check_init (&check, check_cb); |
1756 | ev_check_start (EV_DEFAULT_ &check); |
1908 | ev_check_start (EV_DEFAULT_ &check); |
1757 | ev_loop (EV_DEFAULT_ 0); |
1909 | ev_loop (EV_DEFAULT_ 0); |
1758 | |
1910 | |
1759 | |
|
|
1760 | =head1 EMBEDDING |
1911 | =head1 EMBEDDING |
1761 | |
1912 | |
1762 | Libev can (and often is) directly embedded into host |
1913 | Libev can (and often is) directly embedded into host |
1763 | applications. Examples of applications that embed it include the Deliantra |
1914 | applications. Examples of applications that embed it include the Deliantra |
1764 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1915 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
… | |
… | |
1803 | ev_vars.h |
1954 | ev_vars.h |
1804 | ev_wrap.h |
1955 | ev_wrap.h |
1805 | |
1956 | |
1806 | ev_win32.c required on win32 platforms only |
1957 | ev_win32.c required on win32 platforms only |
1807 | |
1958 | |
1808 | ev_select.c only when select backend is enabled (which is by default) |
1959 | ev_select.c only when select backend is enabled (which is enabled by default) |
1809 | ev_poll.c only when poll backend is enabled (disabled by default) |
1960 | ev_poll.c only when poll backend is enabled (disabled by default) |
1810 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1961 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1811 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1962 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1812 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1963 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1813 | |
1964 | |
… | |
… | |
1938 | |
2089 | |
1939 | =item EV_USE_DEVPOLL |
2090 | =item EV_USE_DEVPOLL |
1940 | |
2091 | |
1941 | reserved for future expansion, works like the USE symbols above. |
2092 | reserved for future expansion, works like the USE symbols above. |
1942 | |
2093 | |
|
|
2094 | =item EV_USE_INOTIFY |
|
|
2095 | |
|
|
2096 | If defined to be C<1>, libev will compile in support for the Linux inotify |
|
|
2097 | interface to speed up C<ev_stat> watchers. Its actual availability will |
|
|
2098 | be detected at runtime. |
|
|
2099 | |
1943 | =item EV_H |
2100 | =item EV_H |
1944 | |
2101 | |
1945 | The name of the F<ev.h> header file used to include it. The default if |
2102 | The name of the F<ev.h> header file used to include it. The default if |
1946 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
2103 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
1947 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
2104 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
… | |
… | |
1970 | will have the C<struct ev_loop *> as first argument, and you can create |
2127 | will have the C<struct ev_loop *> as first argument, and you can create |
1971 | additional independent event loops. Otherwise there will be no support |
2128 | additional independent event loops. Otherwise there will be no support |
1972 | for multiple event loops and there is no first event loop pointer |
2129 | for multiple event loops and there is no first event loop pointer |
1973 | argument. Instead, all functions act on the single default loop. |
2130 | argument. Instead, all functions act on the single default loop. |
1974 | |
2131 | |
|
|
2132 | =item EV_MINPRI |
|
|
2133 | |
|
|
2134 | =item EV_MAXPRI |
|
|
2135 | |
|
|
2136 | The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to |
|
|
2137 | C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can |
|
|
2138 | provide for more priorities by overriding those symbols (usually defined |
|
|
2139 | to be C<-2> and C<2>, respectively). |
|
|
2140 | |
|
|
2141 | When doing priority-based operations, libev usually has to linearly search |
|
|
2142 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2143 | and time, so using the defaults of five priorities (-2 .. +2) is usually |
|
|
2144 | fine. |
|
|
2145 | |
|
|
2146 | If your embedding app does not need any priorities, defining these both to |
|
|
2147 | C<0> will save some memory and cpu. |
|
|
2148 | |
1975 | =item EV_PERIODIC_ENABLE |
2149 | =item EV_PERIODIC_ENABLE |
1976 | |
2150 | |
1977 | If undefined or defined to be C<1>, then periodic timers are supported. If |
2151 | If undefined or defined to be C<1>, then periodic timers are supported. If |
1978 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2152 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
1979 | code. |
2153 | code. |
1980 | |
2154 | |
|
|
2155 | =item EV_IDLE_ENABLE |
|
|
2156 | |
|
|
2157 | If undefined or defined to be C<1>, then idle watchers are supported. If |
|
|
2158 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2159 | code. |
|
|
2160 | |
1981 | =item EV_EMBED_ENABLE |
2161 | =item EV_EMBED_ENABLE |
1982 | |
2162 | |
1983 | If undefined or defined to be C<1>, then embed watchers are supported. If |
2163 | If undefined or defined to be C<1>, then embed watchers are supported. If |
1984 | defined to be C<0>, then they are not. |
2164 | defined to be C<0>, then they are not. |
1985 | |
2165 | |
… | |
… | |
2002 | =item EV_PID_HASHSIZE |
2182 | =item EV_PID_HASHSIZE |
2003 | |
2183 | |
2004 | C<ev_child> watchers use a small hash table to distribute workload by |
2184 | C<ev_child> watchers use a small hash table to distribute workload by |
2005 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
2185 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
2006 | than enough. If you need to manage thousands of children you might want to |
2186 | than enough. If you need to manage thousands of children you might want to |
2007 | increase this value. |
2187 | increase this value (I<must> be a power of two). |
|
|
2188 | |
|
|
2189 | =item EV_INOTIFY_HASHSIZE |
|
|
2190 | |
|
|
2191 | C<ev_staz> watchers use a small hash table to distribute workload by |
|
|
2192 | inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>), |
|
|
2193 | usually more than enough. If you need to manage thousands of C<ev_stat> |
|
|
2194 | watchers you might want to increase this value (I<must> be a power of |
|
|
2195 | two). |
2008 | |
2196 | |
2009 | =item EV_COMMON |
2197 | =item EV_COMMON |
2010 | |
2198 | |
2011 | By default, all watchers have a C<void *data> member. By redefining |
2199 | By default, all watchers have a C<void *data> member. By redefining |
2012 | this macro to a something else you can include more and other types of |
2200 | this macro to a something else you can include more and other types of |
… | |
… | |
2041 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2229 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2042 | will be compiled. It is pretty complex because it provides its own header |
2230 | will be compiled. It is pretty complex because it provides its own header |
2043 | file. |
2231 | file. |
2044 | |
2232 | |
2045 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2233 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2046 | that everybody includes and which overrides some autoconf choices: |
2234 | that everybody includes and which overrides some configure choices: |
2047 | |
2235 | |
|
|
2236 | #define EV_MINIMAL 1 |
2048 | #define EV_USE_POLL 0 |
2237 | #define EV_USE_POLL 0 |
2049 | #define EV_MULTIPLICITY 0 |
2238 | #define EV_MULTIPLICITY 0 |
2050 | #define EV_PERIODICS 0 |
2239 | #define EV_PERIODIC_ENABLE 0 |
|
|
2240 | #define EV_STAT_ENABLE 0 |
|
|
2241 | #define EV_FORK_ENABLE 0 |
2051 | #define EV_CONFIG_H <config.h> |
2242 | #define EV_CONFIG_H <config.h> |
|
|
2243 | #define EV_MINPRI 0 |
|
|
2244 | #define EV_MAXPRI 0 |
2052 | |
2245 | |
2053 | #include "ev++.h" |
2246 | #include "ev++.h" |
2054 | |
2247 | |
2055 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2248 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2056 | |
2249 | |
… | |
… | |
2062 | |
2255 | |
2063 | In this section the complexities of (many of) the algorithms used inside |
2256 | In this section the complexities of (many of) the algorithms used inside |
2064 | libev will be explained. For complexity discussions about backends see the |
2257 | libev will be explained. For complexity discussions about backends see the |
2065 | documentation for C<ev_default_init>. |
2258 | documentation for C<ev_default_init>. |
2066 | |
2259 | |
|
|
2260 | All of the following are about amortised time: If an array needs to be |
|
|
2261 | extended, libev needs to realloc and move the whole array, but this |
|
|
2262 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2263 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2264 | it is much faster and asymptotically approaches constant time. |
|
|
2265 | |
2067 | =over 4 |
2266 | =over 4 |
2068 | |
2267 | |
2069 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2268 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2070 | |
2269 | |
|
|
2270 | This means that, when you have a watcher that triggers in one hour and |
|
|
2271 | there are 100 watchers that would trigger before that then inserting will |
|
|
2272 | have to skip those 100 watchers. |
|
|
2273 | |
2071 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2274 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2072 | |
2275 | |
|
|
2276 | That means that for changing a timer costs less than removing/adding them |
|
|
2277 | as only the relative motion in the event queue has to be paid for. |
|
|
2278 | |
2073 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2279 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2074 | |
2280 | |
|
|
2281 | These just add the watcher into an array or at the head of a list. |
2075 | =item Stopping check/prepare/idle watchers: O(1) |
2282 | =item Stopping check/prepare/idle watchers: O(1) |
2076 | |
2283 | |
2077 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16)) |
2284 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
|
|
2285 | |
|
|
2286 | These watchers are stored in lists then need to be walked to find the |
|
|
2287 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2288 | have many watchers waiting for the same fd or signal). |
2078 | |
2289 | |
2079 | =item Finding the next timer per loop iteration: O(1) |
2290 | =item Finding the next timer per loop iteration: O(1) |
2080 | |
2291 | |
2081 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2292 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2082 | |
2293 | |
|
|
2294 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2295 | libev to recalculate its status (and possibly tell the kernel). |
|
|
2296 | |
2083 | =item Activating one watcher: O(1) |
2297 | =item Activating one watcher: O(1) |
2084 | |
2298 | |
|
|
2299 | =item Priority handling: O(number_of_priorities) |
|
|
2300 | |
|
|
2301 | Priorities are implemented by allocating some space for each |
|
|
2302 | priority. When doing priority-based operations, libev usually has to |
|
|
2303 | linearly search all the priorities. |
|
|
2304 | |
2085 | =back |
2305 | =back |
2086 | |
2306 | |
2087 | |
2307 | |
2088 | =head1 AUTHOR |
2308 | =head1 AUTHOR |
2089 | |
2309 | |