… | |
… | |
2 | |
2 | |
3 | libev - a high performance full-featured event loop written in C |
3 | libev - a high performance full-featured event loop written in C |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | /* this is the only header you need */ |
|
|
8 | #include <ev.h> |
7 | #include <ev.h> |
9 | |
8 | |
10 | /* what follows is a fully working example program */ |
9 | =head1 EXAMPLE PROGRAM |
|
|
10 | |
|
|
11 | #include <ev.h> |
|
|
12 | |
11 | ev_io stdin_watcher; |
13 | ev_io stdin_watcher; |
12 | ev_timer timeout_watcher; |
14 | ev_timer timeout_watcher; |
13 | |
15 | |
14 | /* called when data readable on stdin */ |
16 | /* called when data readable on stdin */ |
15 | static void |
17 | static void |
… | |
… | |
61 | details of the event, and then hand it over to libev by I<starting> the |
63 | details of the event, and then hand it over to libev by I<starting> the |
62 | watcher. |
64 | watcher. |
63 | |
65 | |
64 | =head1 FEATURES |
66 | =head1 FEATURES |
65 | |
67 | |
66 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
68 | Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the |
67 | kqueue mechanisms for file descriptor events, relative timers, absolute |
69 | BSD-specific C<kqueue> and the Solaris-specific event port mechanisms |
68 | timers with customised rescheduling, signal events, process status change |
70 | for file descriptor events (C<ev_io>), the Linux C<inotify> interface |
69 | events (related to SIGCHLD), and event watchers dealing with the event |
71 | (for C<ev_stat>), relative timers (C<ev_timer>), absolute timers |
70 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
72 | with customised rescheduling (C<ev_periodic>), synchronous signals |
|
|
73 | (C<ev_signal>), process status change events (C<ev_child>), and event |
|
|
74 | watchers dealing with the event loop mechanism itself (C<ev_idle>, |
|
|
75 | C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as |
|
|
76 | file watchers (C<ev_stat>) and even limited support for fork events |
|
|
77 | (C<ev_fork>). |
|
|
78 | |
|
|
79 | It also is quite fast (see this |
71 | fast (see this L<benchmark|http://libev.schmorp.de/bench.html> comparing |
80 | L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent |
72 | it to libevent for example). |
81 | for example). |
73 | |
82 | |
74 | =head1 CONVENTIONS |
83 | =head1 CONVENTIONS |
75 | |
84 | |
76 | Libev is very configurable. In this manual the default configuration |
85 | Libev is very configurable. In this manual the default configuration will |
77 | will be described, which supports multiple event loops. For more info |
86 | be described, which supports multiple event loops. For more info about |
78 | about various configuration options please have a look at the file |
87 | various configuration options please have a look at B<EMBED> section in |
79 | F<README.embed> in the libev distribution. If libev was configured without |
88 | this manual. If libev was configured without support for multiple event |
80 | support for multiple event loops, then all functions taking an initial |
89 | loops, then all functions taking an initial argument of name C<loop> |
81 | argument of name C<loop> (which is always of type C<struct ev_loop *>) |
90 | (which is always of type C<struct ev_loop *>) will not have this argument. |
82 | will not have this argument. |
|
|
83 | |
91 | |
84 | =head1 TIME REPRESENTATION |
92 | =head1 TIME REPRESENTATION |
85 | |
93 | |
86 | Libev represents time as a single floating point number, representing the |
94 | Libev represents time as a single floating point number, representing the |
87 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
95 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
… | |
… | |
116 | Usually, it's a good idea to terminate if the major versions mismatch, |
124 | Usually, it's a good idea to terminate if the major versions mismatch, |
117 | as this indicates an incompatible change. Minor versions are usually |
125 | as this indicates an incompatible change. Minor versions are usually |
118 | compatible to older versions, so a larger minor version alone is usually |
126 | compatible to older versions, so a larger minor version alone is usually |
119 | not a problem. |
127 | not a problem. |
120 | |
128 | |
121 | Example: make sure we haven't accidentally been linked against the wrong |
129 | Example: Make sure we haven't accidentally been linked against the wrong |
122 | version: |
130 | version. |
123 | |
131 | |
124 | assert (("libev version mismatch", |
132 | assert (("libev version mismatch", |
125 | ev_version_major () == EV_VERSION_MAJOR |
133 | ev_version_major () == EV_VERSION_MAJOR |
126 | && ev_version_minor () >= EV_VERSION_MINOR)); |
134 | && ev_version_minor () >= EV_VERSION_MINOR)); |
127 | |
135 | |
… | |
… | |
155 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
163 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
156 | recommended ones. |
164 | recommended ones. |
157 | |
165 | |
158 | See the description of C<ev_embed> watchers for more info. |
166 | See the description of C<ev_embed> watchers for more info. |
159 | |
167 | |
160 | =item ev_set_allocator (void *(*cb)(void *ptr, size_t size)) |
168 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
161 | |
169 | |
162 | Sets the allocation function to use (the prototype and semantics are |
170 | Sets the allocation function to use (the prototype is similar - the |
163 | identical to the realloc C function). It is used to allocate and free |
171 | semantics is identical - to the realloc C function). It is used to |
164 | memory (no surprises here). If it returns zero when memory needs to be |
172 | allocate and free memory (no surprises here). If it returns zero when |
165 | allocated, the library might abort or take some potentially destructive |
173 | memory needs to be allocated, the library might abort or take some |
166 | action. The default is your system realloc function. |
174 | potentially destructive action. The default is your system realloc |
|
|
175 | function. |
167 | |
176 | |
168 | You could override this function in high-availability programs to, say, |
177 | You could override this function in high-availability programs to, say, |
169 | free some memory if it cannot allocate memory, to use a special allocator, |
178 | free some memory if it cannot allocate memory, to use a special allocator, |
170 | or even to sleep a while and retry until some memory is available. |
179 | or even to sleep a while and retry until some memory is available. |
171 | |
180 | |
172 | Example: replace the libev allocator with one that waits a bit and then |
181 | Example: Replace the libev allocator with one that waits a bit and then |
173 | retries: better than mine). |
182 | retries). |
174 | |
183 | |
175 | static void * |
184 | static void * |
176 | persistent_realloc (void *ptr, size_t size) |
185 | persistent_realloc (void *ptr, size_t size) |
177 | { |
186 | { |
178 | for (;;) |
187 | for (;;) |
… | |
… | |
197 | callback is set, then libev will expect it to remedy the sitution, no |
206 | callback is set, then libev will expect it to remedy the sitution, no |
198 | matter what, when it returns. That is, libev will generally retry the |
207 | matter what, when it returns. That is, libev will generally retry the |
199 | requested operation, or, if the condition doesn't go away, do bad stuff |
208 | requested operation, or, if the condition doesn't go away, do bad stuff |
200 | (such as abort). |
209 | (such as abort). |
201 | |
210 | |
202 | Example: do the same thing as libev does internally: |
211 | Example: This is basically the same thing that libev does internally, too. |
203 | |
212 | |
204 | static void |
213 | static void |
205 | fatal_error (const char *msg) |
214 | fatal_error (const char *msg) |
206 | { |
215 | { |
207 | perror (msg); |
216 | perror (msg); |
… | |
… | |
257 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
266 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
258 | override the flags completely if it is found in the environment. This is |
267 | override the flags completely if it is found in the environment. This is |
259 | useful to try out specific backends to test their performance, or to work |
268 | useful to try out specific backends to test their performance, or to work |
260 | around bugs. |
269 | around bugs. |
261 | |
270 | |
|
|
271 | =item C<EVFLAG_FORKCHECK> |
|
|
272 | |
|
|
273 | Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after |
|
|
274 | a fork, you can also make libev check for a fork in each iteration by |
|
|
275 | enabling this flag. |
|
|
276 | |
|
|
277 | This works by calling C<getpid ()> on every iteration of the loop, |
|
|
278 | and thus this might slow down your event loop if you do a lot of loop |
|
|
279 | iterations and little real work, but is usually not noticeable (on my |
|
|
280 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
|
|
281 | without a syscall and thus I<very> fast, but my Linux system also has |
|
|
282 | C<pthread_atfork> which is even faster). |
|
|
283 | |
|
|
284 | The big advantage of this flag is that you can forget about fork (and |
|
|
285 | forget about forgetting to tell libev about forking) when you use this |
|
|
286 | flag. |
|
|
287 | |
|
|
288 | This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS> |
|
|
289 | environment variable. |
|
|
290 | |
262 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
291 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
263 | |
292 | |
264 | This is your standard select(2) backend. Not I<completely> standard, as |
293 | This is your standard select(2) backend. Not I<completely> standard, as |
265 | libev tries to roll its own fd_set with no limits on the number of fds, |
294 | libev tries to roll its own fd_set with no limits on the number of fds, |
266 | but if that fails, expect a fairly low limit on the number of fds when |
295 | but if that fails, expect a fairly low limit on the number of fds when |
… | |
… | |
353 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
382 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
354 | always distinct from the default loop. Unlike the default loop, it cannot |
383 | always distinct from the default loop. Unlike the default loop, it cannot |
355 | handle signal and child watchers, and attempts to do so will be greeted by |
384 | handle signal and child watchers, and attempts to do so will be greeted by |
356 | undefined behaviour (or a failed assertion if assertions are enabled). |
385 | undefined behaviour (or a failed assertion if assertions are enabled). |
357 | |
386 | |
358 | Example: try to create a event loop that uses epoll and nothing else. |
387 | Example: Try to create a event loop that uses epoll and nothing else. |
359 | |
388 | |
360 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
389 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
361 | if (!epoller) |
390 | if (!epoller) |
362 | fatal ("no epoll found here, maybe it hides under your chair"); |
391 | fatal ("no epoll found here, maybe it hides under your chair"); |
363 | |
392 | |
… | |
… | |
400 | =item ev_loop_fork (loop) |
429 | =item ev_loop_fork (loop) |
401 | |
430 | |
402 | Like C<ev_default_fork>, but acts on an event loop created by |
431 | Like C<ev_default_fork>, but acts on an event loop created by |
403 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
432 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
404 | after fork, and how you do this is entirely your own problem. |
433 | after fork, and how you do this is entirely your own problem. |
|
|
434 | |
|
|
435 | =item unsigned int ev_loop_count (loop) |
|
|
436 | |
|
|
437 | Returns the count of loop iterations for the loop, which is identical to |
|
|
438 | the number of times libev did poll for new events. It starts at C<0> and |
|
|
439 | happily wraps around with enough iterations. |
|
|
440 | |
|
|
441 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
442 | "ticks" the number of loop iterations), as it roughly corresponds with |
|
|
443 | C<ev_prepare> and C<ev_check> calls. |
405 | |
444 | |
406 | =item unsigned int ev_backend (loop) |
445 | =item unsigned int ev_backend (loop) |
407 | |
446 | |
408 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
447 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
409 | use. |
448 | use. |
… | |
… | |
462 | Signals and child watchers are implemented as I/O watchers, and will |
501 | Signals and child watchers are implemented as I/O watchers, and will |
463 | be handled here by queueing them when their watcher gets executed. |
502 | be handled here by queueing them when their watcher gets executed. |
464 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
503 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
465 | were used, return, otherwise continue with step *. |
504 | were used, return, otherwise continue with step *. |
466 | |
505 | |
467 | Example: queue some jobs and then loop until no events are outsanding |
506 | Example: Queue some jobs and then loop until no events are outsanding |
468 | anymore. |
507 | anymore. |
469 | |
508 | |
470 | ... queue jobs here, make sure they register event watchers as long |
509 | ... queue jobs here, make sure they register event watchers as long |
471 | ... as they still have work to do (even an idle watcher will do..) |
510 | ... as they still have work to do (even an idle watcher will do..) |
472 | ev_loop (my_loop, 0); |
511 | ev_loop (my_loop, 0); |
… | |
… | |
492 | visible to the libev user and should not keep C<ev_loop> from exiting if |
531 | visible to the libev user and should not keep C<ev_loop> from exiting if |
493 | no event watchers registered by it are active. It is also an excellent |
532 | no event watchers registered by it are active. It is also an excellent |
494 | way to do this for generic recurring timers or from within third-party |
533 | way to do this for generic recurring timers or from within third-party |
495 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
534 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
496 | |
535 | |
497 | Example: create a signal watcher, but keep it from keeping C<ev_loop> |
536 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
498 | running when nothing else is active. |
537 | running when nothing else is active. |
499 | |
538 | |
500 | struct dv_signal exitsig; |
539 | struct ev_signal exitsig; |
501 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
540 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
502 | ev_signal_start (myloop, &exitsig); |
541 | ev_signal_start (loop, &exitsig); |
503 | evf_unref (myloop); |
542 | evf_unref (loop); |
504 | |
543 | |
505 | Example: for some weird reason, unregister the above signal handler again. |
544 | Example: For some weird reason, unregister the above signal handler again. |
506 | |
545 | |
507 | ev_ref (myloop); |
546 | ev_ref (loop); |
508 | ev_signal_stop (myloop, &exitsig); |
547 | ev_signal_stop (loop, &exitsig); |
509 | |
548 | |
510 | =back |
549 | =back |
511 | |
550 | |
512 | |
551 | |
513 | =head1 ANATOMY OF A WATCHER |
552 | =head1 ANATOMY OF A WATCHER |
… | |
… | |
696 | events but its callback has not yet been invoked). As long as a watcher |
735 | events but its callback has not yet been invoked). As long as a watcher |
697 | is pending (but not active) you must not call an init function on it (but |
736 | is pending (but not active) you must not call an init function on it (but |
698 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
737 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
699 | libev (e.g. you cnanot C<free ()> it). |
738 | libev (e.g. you cnanot C<free ()> it). |
700 | |
739 | |
701 | =item callback = ev_cb (ev_TYPE *watcher) |
740 | =item callback ev_cb (ev_TYPE *watcher) |
702 | |
741 | |
703 | Returns the callback currently set on the watcher. |
742 | Returns the callback currently set on the watcher. |
704 | |
743 | |
705 | =item ev_cb_set (ev_TYPE *watcher, callback) |
744 | =item ev_cb_set (ev_TYPE *watcher, callback) |
706 | |
745 | |
707 | Change the callback. You can change the callback at virtually any time |
746 | Change the callback. You can change the callback at virtually any time |
708 | (modulo threads). |
747 | (modulo threads). |
|
|
748 | |
|
|
749 | =item ev_set_priority (ev_TYPE *watcher, priority) |
|
|
750 | |
|
|
751 | =item int ev_priority (ev_TYPE *watcher) |
|
|
752 | |
|
|
753 | Set and query the priority of the watcher. The priority is a small |
|
|
754 | integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> |
|
|
755 | (default: C<-2>). Pending watchers with higher priority will be invoked |
|
|
756 | before watchers with lower priority, but priority will not keep watchers |
|
|
757 | from being executed (except for C<ev_idle> watchers). |
|
|
758 | |
|
|
759 | This means that priorities are I<only> used for ordering callback |
|
|
760 | invocation after new events have been received. This is useful, for |
|
|
761 | example, to reduce latency after idling, or more often, to bind two |
|
|
762 | watchers on the same event and make sure one is called first. |
|
|
763 | |
|
|
764 | If you need to suppress invocation when higher priority events are pending |
|
|
765 | you need to look at C<ev_idle> watchers, which provide this functionality. |
|
|
766 | |
|
|
767 | The default priority used by watchers when no priority has been set is |
|
|
768 | always C<0>, which is supposed to not be too high and not be too low :). |
|
|
769 | |
|
|
770 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
|
|
771 | fine, as long as you do not mind that the priority value you query might |
|
|
772 | or might not have been adjusted to be within valid range. |
709 | |
773 | |
710 | =back |
774 | =back |
711 | |
775 | |
712 | |
776 | |
713 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
777 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
734 | { |
798 | { |
735 | struct my_io *w = (struct my_io *)w_; |
799 | struct my_io *w = (struct my_io *)w_; |
736 | ... |
800 | ... |
737 | } |
801 | } |
738 | |
802 | |
739 | More interesting and less C-conformant ways of catsing your callback type |
803 | More interesting and less C-conformant ways of casting your callback type |
740 | have been omitted.... |
804 | instead have been omitted. |
|
|
805 | |
|
|
806 | Another common scenario is having some data structure with multiple |
|
|
807 | watchers: |
|
|
808 | |
|
|
809 | struct my_biggy |
|
|
810 | { |
|
|
811 | int some_data; |
|
|
812 | ev_timer t1; |
|
|
813 | ev_timer t2; |
|
|
814 | } |
|
|
815 | |
|
|
816 | In this case getting the pointer to C<my_biggy> is a bit more complicated, |
|
|
817 | you need to use C<offsetof>: |
|
|
818 | |
|
|
819 | #include <stddef.h> |
|
|
820 | |
|
|
821 | static void |
|
|
822 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
823 | { |
|
|
824 | struct my_biggy big = (struct my_biggy * |
|
|
825 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
826 | } |
|
|
827 | |
|
|
828 | static void |
|
|
829 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
830 | { |
|
|
831 | struct my_biggy big = (struct my_biggy * |
|
|
832 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
833 | } |
741 | |
834 | |
742 | |
835 | |
743 | =head1 WATCHER TYPES |
836 | =head1 WATCHER TYPES |
744 | |
837 | |
745 | This section describes each watcher in detail, but will not repeat |
838 | This section describes each watcher in detail, but will not repeat |
… | |
… | |
814 | |
907 | |
815 | The events being watched. |
908 | The events being watched. |
816 | |
909 | |
817 | =back |
910 | =back |
818 | |
911 | |
819 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
912 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
820 | readable, but only once. Since it is likely line-buffered, you could |
913 | readable, but only once. Since it is likely line-buffered, you could |
821 | attempt to read a whole line in the callback: |
914 | attempt to read a whole line in the callback. |
822 | |
915 | |
823 | static void |
916 | static void |
824 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
917 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
825 | { |
918 | { |
826 | ev_io_stop (loop, w); |
919 | ev_io_stop (loop, w); |
… | |
… | |
878 | =item ev_timer_again (loop) |
971 | =item ev_timer_again (loop) |
879 | |
972 | |
880 | This will act as if the timer timed out and restart it again if it is |
973 | This will act as if the timer timed out and restart it again if it is |
881 | repeating. The exact semantics are: |
974 | repeating. The exact semantics are: |
882 | |
975 | |
|
|
976 | If the timer is pending, its pending status is cleared. |
|
|
977 | |
883 | If the timer is started but nonrepeating, stop it. |
978 | If the timer is started but nonrepeating, stop it (as if it timed out). |
884 | |
979 | |
885 | If the timer is repeating, either start it if necessary (with the repeat |
980 | If the timer is repeating, either start it if necessary (with the |
886 | value), or reset the running timer to the repeat value. |
981 | C<repeat> value), or reset the running timer to the C<repeat> value. |
887 | |
982 | |
888 | This sounds a bit complicated, but here is a useful and typical |
983 | This sounds a bit complicated, but here is a useful and typical |
889 | example: Imagine you have a tcp connection and you want a so-called |
984 | example: Imagine you have a tcp connection and you want a so-called idle |
890 | idle timeout, that is, you want to be called when there have been, |
985 | timeout, that is, you want to be called when there have been, say, 60 |
891 | say, 60 seconds of inactivity on the socket. The easiest way to do |
986 | seconds of inactivity on the socket. The easiest way to do this is to |
892 | this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling |
987 | configure an C<ev_timer> with a C<repeat> value of C<60> and then call |
893 | C<ev_timer_again> each time you successfully read or write some data. If |
988 | C<ev_timer_again> each time you successfully read or write some data. If |
894 | you go into an idle state where you do not expect data to travel on the |
989 | you go into an idle state where you do not expect data to travel on the |
895 | socket, you can stop the timer, and again will automatically restart it if |
990 | socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will |
896 | need be. |
991 | automatically restart it if need be. |
897 | |
992 | |
898 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
993 | That means you can ignore the C<after> value and C<ev_timer_start> |
899 | and only ever use the C<repeat> value: |
994 | altogether and only ever use the C<repeat> value and C<ev_timer_again>: |
900 | |
995 | |
901 | ev_timer_init (timer, callback, 0., 5.); |
996 | ev_timer_init (timer, callback, 0., 5.); |
902 | ev_timer_again (loop, timer); |
997 | ev_timer_again (loop, timer); |
903 | ... |
998 | ... |
904 | timer->again = 17.; |
999 | timer->again = 17.; |
905 | ev_timer_again (loop, timer); |
1000 | ev_timer_again (loop, timer); |
906 | ... |
1001 | ... |
907 | timer->again = 10.; |
1002 | timer->again = 10.; |
908 | ev_timer_again (loop, timer); |
1003 | ev_timer_again (loop, timer); |
909 | |
1004 | |
910 | This is more efficient then stopping/starting the timer eahc time you want |
1005 | This is more slightly efficient then stopping/starting the timer each time |
911 | to modify its timeout value. |
1006 | you want to modify its timeout value. |
912 | |
1007 | |
913 | =item ev_tstamp repeat [read-write] |
1008 | =item ev_tstamp repeat [read-write] |
914 | |
1009 | |
915 | The current C<repeat> value. Will be used each time the watcher times out |
1010 | The current C<repeat> value. Will be used each time the watcher times out |
916 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1011 | or C<ev_timer_again> is called and determines the next timeout (if any), |
917 | which is also when any modifications are taken into account. |
1012 | which is also when any modifications are taken into account. |
918 | |
1013 | |
919 | =back |
1014 | =back |
920 | |
1015 | |
921 | Example: create a timer that fires after 60 seconds. |
1016 | Example: Create a timer that fires after 60 seconds. |
922 | |
1017 | |
923 | static void |
1018 | static void |
924 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1019 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
925 | { |
1020 | { |
926 | .. one minute over, w is actually stopped right here |
1021 | .. one minute over, w is actually stopped right here |
… | |
… | |
928 | |
1023 | |
929 | struct ev_timer mytimer; |
1024 | struct ev_timer mytimer; |
930 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1025 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
931 | ev_timer_start (loop, &mytimer); |
1026 | ev_timer_start (loop, &mytimer); |
932 | |
1027 | |
933 | Example: create a timeout timer that times out after 10 seconds of |
1028 | Example: Create a timeout timer that times out after 10 seconds of |
934 | inactivity. |
1029 | inactivity. |
935 | |
1030 | |
936 | static void |
1031 | static void |
937 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1032 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
938 | { |
1033 | { |
… | |
… | |
1063 | switched off. Can be changed any time, but changes only take effect when |
1158 | switched off. Can be changed any time, but changes only take effect when |
1064 | the periodic timer fires or C<ev_periodic_again> is being called. |
1159 | the periodic timer fires or C<ev_periodic_again> is being called. |
1065 | |
1160 | |
1066 | =back |
1161 | =back |
1067 | |
1162 | |
1068 | Example: call a callback every hour, or, more precisely, whenever the |
1163 | Example: Call a callback every hour, or, more precisely, whenever the |
1069 | system clock is divisible by 3600. The callback invocation times have |
1164 | system clock is divisible by 3600. The callback invocation times have |
1070 | potentially a lot of jittering, but good long-term stability. |
1165 | potentially a lot of jittering, but good long-term stability. |
1071 | |
1166 | |
1072 | static void |
1167 | static void |
1073 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1168 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
1077 | |
1172 | |
1078 | struct ev_periodic hourly_tick; |
1173 | struct ev_periodic hourly_tick; |
1079 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1174 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1080 | ev_periodic_start (loop, &hourly_tick); |
1175 | ev_periodic_start (loop, &hourly_tick); |
1081 | |
1176 | |
1082 | Example: the same as above, but use a reschedule callback to do it: |
1177 | Example: The same as above, but use a reschedule callback to do it: |
1083 | |
1178 | |
1084 | #include <math.h> |
1179 | #include <math.h> |
1085 | |
1180 | |
1086 | static ev_tstamp |
1181 | static ev_tstamp |
1087 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1182 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
1089 | return fmod (now, 3600.) + 3600.; |
1184 | return fmod (now, 3600.) + 3600.; |
1090 | } |
1185 | } |
1091 | |
1186 | |
1092 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1187 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1093 | |
1188 | |
1094 | Example: call a callback every hour, starting now: |
1189 | Example: Call a callback every hour, starting now: |
1095 | |
1190 | |
1096 | struct ev_periodic hourly_tick; |
1191 | struct ev_periodic hourly_tick; |
1097 | ev_periodic_init (&hourly_tick, clock_cb, |
1192 | ev_periodic_init (&hourly_tick, clock_cb, |
1098 | fmod (ev_now (loop), 3600.), 3600., 0); |
1193 | fmod (ev_now (loop), 3600.), 3600., 0); |
1099 | ev_periodic_start (loop, &hourly_tick); |
1194 | ev_periodic_start (loop, &hourly_tick); |
… | |
… | |
1160 | The process exit/trace status caused by C<rpid> (see your systems |
1255 | The process exit/trace status caused by C<rpid> (see your systems |
1161 | C<waitpid> and C<sys/wait.h> documentation for details). |
1256 | C<waitpid> and C<sys/wait.h> documentation for details). |
1162 | |
1257 | |
1163 | =back |
1258 | =back |
1164 | |
1259 | |
1165 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1260 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1166 | |
1261 | |
1167 | static void |
1262 | static void |
1168 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1263 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1169 | { |
1264 | { |
1170 | ev_unloop (loop, EVUNLOOP_ALL); |
1265 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
1185 | not exist" is a status change like any other. The condition "path does |
1280 | not exist" is a status change like any other. The condition "path does |
1186 | not exist" is signified by the C<st_nlink> field being zero (which is |
1281 | not exist" is signified by the C<st_nlink> field being zero (which is |
1187 | otherwise always forced to be at least one) and all the other fields of |
1282 | otherwise always forced to be at least one) and all the other fields of |
1188 | the stat buffer having unspecified contents. |
1283 | the stat buffer having unspecified contents. |
1189 | |
1284 | |
|
|
1285 | The path I<should> be absolute and I<must not> end in a slash. If it is |
|
|
1286 | relative and your working directory changes, the behaviour is undefined. |
|
|
1287 | |
1190 | Since there is no standard to do this, the portable implementation simply |
1288 | Since there is no standard to do this, the portable implementation simply |
1191 | calls C<stat (2)> regulalry on the path to see if it changed somehow. You |
1289 | calls C<stat (2)> regularly on the path to see if it changed somehow. You |
1192 | can specify a recommended polling interval for this case. If you specify |
1290 | can specify a recommended polling interval for this case. If you specify |
1193 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1291 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1194 | unspecified default> value will be used (which you can expect to be around |
1292 | unspecified default> value will be used (which you can expect to be around |
1195 | five seconds, although this might change dynamically). Libev will also |
1293 | five seconds, although this might change dynamically). Libev will also |
1196 | impose a minimum interval which is currently around C<0.1>, but thats |
1294 | impose a minimum interval which is currently around C<0.1>, but thats |
… | |
… | |
1198 | |
1296 | |
1199 | This watcher type is not meant for massive numbers of stat watchers, |
1297 | This watcher type is not meant for massive numbers of stat watchers, |
1200 | as even with OS-supported change notifications, this can be |
1298 | as even with OS-supported change notifications, this can be |
1201 | resource-intensive. |
1299 | resource-intensive. |
1202 | |
1300 | |
1203 | At the time of this writing, no specific OS backends are implemented, but |
1301 | At the time of this writing, only the Linux inotify interface is |
1204 | if demand increases, at least a kqueue and inotify backend will be added. |
1302 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1303 | reader). Inotify will be used to give hints only and should not change the |
|
|
1304 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
|
|
1305 | to fall back to regular polling again even with inotify, but changes are |
|
|
1306 | usually detected immediately, and if the file exists there will be no |
|
|
1307 | polling. |
1205 | |
1308 | |
1206 | =over 4 |
1309 | =over 4 |
1207 | |
1310 | |
1208 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1311 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1209 | |
1312 | |
… | |
… | |
1273 | ev_stat_start (loop, &passwd); |
1376 | ev_stat_start (loop, &passwd); |
1274 | |
1377 | |
1275 | |
1378 | |
1276 | =head2 C<ev_idle> - when you've got nothing better to do... |
1379 | =head2 C<ev_idle> - when you've got nothing better to do... |
1277 | |
1380 | |
1278 | Idle watchers trigger events when there are no other events are pending |
1381 | Idle watchers trigger events when no other events of the same or higher |
1279 | (prepare, check and other idle watchers do not count). That is, as long |
1382 | priority are pending (prepare, check and other idle watchers do not |
1280 | as your process is busy handling sockets or timeouts (or even signals, |
1383 | count). |
1281 | imagine) it will not be triggered. But when your process is idle all idle |
1384 | |
1282 | watchers are being called again and again, once per event loop iteration - |
1385 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1386 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1387 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1388 | are pending), the idle watchers are being called once per event loop |
1283 | until stopped, that is, or your process receives more events and becomes |
1389 | iteration - until stopped, that is, or your process receives more events |
1284 | busy. |
1390 | and becomes busy again with higher priority stuff. |
1285 | |
1391 | |
1286 | The most noteworthy effect is that as long as any idle watchers are |
1392 | The most noteworthy effect is that as long as any idle watchers are |
1287 | active, the process will not block when waiting for new events. |
1393 | active, the process will not block when waiting for new events. |
1288 | |
1394 | |
1289 | Apart from keeping your process non-blocking (which is a useful |
1395 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1299 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1405 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1300 | believe me. |
1406 | believe me. |
1301 | |
1407 | |
1302 | =back |
1408 | =back |
1303 | |
1409 | |
1304 | Example: dynamically allocate an C<ev_idle>, start it, and in the |
1410 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1305 | callback, free it. Alos, use no error checking, as usual. |
1411 | callback, free it. Also, use no error checking, as usual. |
1306 | |
1412 | |
1307 | static void |
1413 | static void |
1308 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1414 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1309 | { |
1415 | { |
1310 | free (w); |
1416 | free (w); |
… | |
… | |
1389 | |
1495 | |
1390 | // create io watchers for each fd and a timer before blocking |
1496 | // create io watchers for each fd and a timer before blocking |
1391 | static void |
1497 | static void |
1392 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1498 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1393 | { |
1499 | { |
1394 | int timeout = 3600000;truct pollfd fds [nfd]; |
1500 | int timeout = 3600000; |
|
|
1501 | struct pollfd fds [nfd]; |
1395 | // actual code will need to loop here and realloc etc. |
1502 | // actual code will need to loop here and realloc etc. |
1396 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1503 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1397 | |
1504 | |
1398 | /* the callback is illegal, but won't be called as we stop during check */ |
1505 | /* the callback is illegal, but won't be called as we stop during check */ |
1399 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1506 | ev_timer_init (&tw, 0, timeout * 1e-3); |
… | |
… | |
1780 | Similar to the other two macros, this gives you the value of the default |
1887 | Similar to the other two macros, this gives you the value of the default |
1781 | loop, if multiple loops are supported ("ev loop default"). |
1888 | loop, if multiple loops are supported ("ev loop default"). |
1782 | |
1889 | |
1783 | =back |
1890 | =back |
1784 | |
1891 | |
1785 | Example: Declare and initialise a check watcher, working regardless of |
1892 | Example: Declare and initialise a check watcher, utilising the above |
1786 | wether multiple loops are supported or not. |
1893 | macros so it will work regardless of wether multiple loops are supported |
|
|
1894 | or not. |
1787 | |
1895 | |
1788 | static void |
1896 | static void |
1789 | check_cb (EV_P_ ev_timer *w, int revents) |
1897 | check_cb (EV_P_ ev_timer *w, int revents) |
1790 | { |
1898 | { |
1791 | ev_check_stop (EV_A_ w); |
1899 | ev_check_stop (EV_A_ w); |
… | |
… | |
1793 | |
1901 | |
1794 | ev_check check; |
1902 | ev_check check; |
1795 | ev_check_init (&check, check_cb); |
1903 | ev_check_init (&check, check_cb); |
1796 | ev_check_start (EV_DEFAULT_ &check); |
1904 | ev_check_start (EV_DEFAULT_ &check); |
1797 | ev_loop (EV_DEFAULT_ 0); |
1905 | ev_loop (EV_DEFAULT_ 0); |
1798 | |
|
|
1799 | |
1906 | |
1800 | =head1 EMBEDDING |
1907 | =head1 EMBEDDING |
1801 | |
1908 | |
1802 | Libev can (and often is) directly embedded into host |
1909 | Libev can (and often is) directly embedded into host |
1803 | applications. Examples of applications that embed it include the Deliantra |
1910 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1843 | ev_vars.h |
1950 | ev_vars.h |
1844 | ev_wrap.h |
1951 | ev_wrap.h |
1845 | |
1952 | |
1846 | ev_win32.c required on win32 platforms only |
1953 | ev_win32.c required on win32 platforms only |
1847 | |
1954 | |
1848 | ev_select.c only when select backend is enabled (which is by default) |
1955 | ev_select.c only when select backend is enabled (which is enabled by default) |
1849 | ev_poll.c only when poll backend is enabled (disabled by default) |
1956 | ev_poll.c only when poll backend is enabled (disabled by default) |
1850 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1957 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1851 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1958 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1852 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1959 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1853 | |
1960 | |
… | |
… | |
1978 | |
2085 | |
1979 | =item EV_USE_DEVPOLL |
2086 | =item EV_USE_DEVPOLL |
1980 | |
2087 | |
1981 | reserved for future expansion, works like the USE symbols above. |
2088 | reserved for future expansion, works like the USE symbols above. |
1982 | |
2089 | |
|
|
2090 | =item EV_USE_INOTIFY |
|
|
2091 | |
|
|
2092 | If defined to be C<1>, libev will compile in support for the Linux inotify |
|
|
2093 | interface to speed up C<ev_stat> watchers. Its actual availability will |
|
|
2094 | be detected at runtime. |
|
|
2095 | |
1983 | =item EV_H |
2096 | =item EV_H |
1984 | |
2097 | |
1985 | The name of the F<ev.h> header file used to include it. The default if |
2098 | The name of the F<ev.h> header file used to include it. The default if |
1986 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
2099 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
1987 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
2100 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
… | |
… | |
2016 | |
2129 | |
2017 | If undefined or defined to be C<1>, then periodic timers are supported. If |
2130 | If undefined or defined to be C<1>, then periodic timers are supported. If |
2018 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2131 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2019 | code. |
2132 | code. |
2020 | |
2133 | |
|
|
2134 | =item EV_IDLE_ENABLE |
|
|
2135 | |
|
|
2136 | If undefined or defined to be C<1>, then idle watchers are supported. If |
|
|
2137 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2138 | code. |
|
|
2139 | |
2021 | =item EV_EMBED_ENABLE |
2140 | =item EV_EMBED_ENABLE |
2022 | |
2141 | |
2023 | If undefined or defined to be C<1>, then embed watchers are supported. If |
2142 | If undefined or defined to be C<1>, then embed watchers are supported. If |
2024 | defined to be C<0>, then they are not. |
2143 | defined to be C<0>, then they are not. |
2025 | |
2144 | |
… | |
… | |
2042 | =item EV_PID_HASHSIZE |
2161 | =item EV_PID_HASHSIZE |
2043 | |
2162 | |
2044 | C<ev_child> watchers use a small hash table to distribute workload by |
2163 | C<ev_child> watchers use a small hash table to distribute workload by |
2045 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
2164 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
2046 | than enough. If you need to manage thousands of children you might want to |
2165 | than enough. If you need to manage thousands of children you might want to |
2047 | increase this value. |
2166 | increase this value (I<must> be a power of two). |
|
|
2167 | |
|
|
2168 | =item EV_INOTIFY_HASHSIZE |
|
|
2169 | |
|
|
2170 | C<ev_staz> watchers use a small hash table to distribute workload by |
|
|
2171 | inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>), |
|
|
2172 | usually more than enough. If you need to manage thousands of C<ev_stat> |
|
|
2173 | watchers you might want to increase this value (I<must> be a power of |
|
|
2174 | two). |
2048 | |
2175 | |
2049 | =item EV_COMMON |
2176 | =item EV_COMMON |
2050 | |
2177 | |
2051 | By default, all watchers have a C<void *data> member. By redefining |
2178 | By default, all watchers have a C<void *data> member. By redefining |
2052 | this macro to a something else you can include more and other types of |
2179 | this macro to a something else you can include more and other types of |
… | |
… | |
2081 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2208 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2082 | will be compiled. It is pretty complex because it provides its own header |
2209 | will be compiled. It is pretty complex because it provides its own header |
2083 | file. |
2210 | file. |
2084 | |
2211 | |
2085 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2212 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2086 | that everybody includes and which overrides some autoconf choices: |
2213 | that everybody includes and which overrides some configure choices: |
2087 | |
2214 | |
|
|
2215 | #define EV_MINIMAL 1 |
2088 | #define EV_USE_POLL 0 |
2216 | #define EV_USE_POLL 0 |
2089 | #define EV_MULTIPLICITY 0 |
2217 | #define EV_MULTIPLICITY 0 |
2090 | #define EV_PERIODICS 0 |
2218 | #define EV_PERIODIC_ENABLE 0 |
|
|
2219 | #define EV_STAT_ENABLE 0 |
|
|
2220 | #define EV_FORK_ENABLE 0 |
2091 | #define EV_CONFIG_H <config.h> |
2221 | #define EV_CONFIG_H <config.h> |
|
|
2222 | #define EV_MINPRI 0 |
|
|
2223 | #define EV_MAXPRI 0 |
2092 | |
2224 | |
2093 | #include "ev++.h" |
2225 | #include "ev++.h" |
2094 | |
2226 | |
2095 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2227 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2096 | |
2228 | |
… | |
… | |
2112 | |
2244 | |
2113 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2245 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2114 | |
2246 | |
2115 | =item Stopping check/prepare/idle watchers: O(1) |
2247 | =item Stopping check/prepare/idle watchers: O(1) |
2116 | |
2248 | |
2117 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16)) |
2249 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2118 | |
2250 | |
2119 | =item Finding the next timer per loop iteration: O(1) |
2251 | =item Finding the next timer per loop iteration: O(1) |
2120 | |
2252 | |
2121 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2253 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2122 | |
2254 | |