… | |
… | |
127 | .\} |
127 | .\} |
128 | .rm #[ #] #H #V #F C |
128 | .rm #[ #] #H #V #F C |
129 | .\" ======================================================================== |
129 | .\" ======================================================================== |
130 | .\" |
130 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-28" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-09" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
137 | .Vb 1 |
… | |
… | |
196 | \& return 0; |
196 | \& return 0; |
197 | \& } |
197 | \& } |
198 | .Ve |
198 | .Ve |
199 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
|
|
201 | The newest version of this document is also available as a html-formatted |
|
|
202 | web page you might find easier to navigate when reading it for the first |
|
|
203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
|
|
204 | .PP |
201 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
202 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occuring), and it will manage |
203 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
204 | .PP |
208 | .PP |
205 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
… | |
… | |
210 | watchers\fR, which are relatively small C structures you initialise with the |
214 | watchers\fR, which are relatively small C structures you initialise with the |
211 | details of the event, and then hand it over to libev by \fIstarting\fR the |
215 | details of the event, and then hand it over to libev by \fIstarting\fR the |
212 | watcher. |
216 | watcher. |
213 | .SH "FEATURES" |
217 | .SH "FEATURES" |
214 | .IX Header "FEATURES" |
218 | .IX Header "FEATURES" |
215 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
219 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
216 | bsd-specific \f(CW\*(C`kqueue\*(C'\fR and the solaris-specific event port mechanisms |
220 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
217 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), |
221 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
|
|
222 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
218 | absolute timers with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous |
223 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
219 | signals (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and |
224 | (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and event |
220 | event watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
225 | watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
221 | \&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as |
226 | \&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as |
222 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
227 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
223 | (\f(CW\*(C`ev_fork\*(C'\fR). |
228 | (\f(CW\*(C`ev_fork\*(C'\fR). |
224 | .PP |
229 | .PP |
225 | It also is quite fast (see this |
230 | It also is quite fast (see this |
… | |
… | |
304 | might be supported on the current system, you would need to look at |
309 | might be supported on the current system, you would need to look at |
305 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
310 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
306 | recommended ones. |
311 | recommended ones. |
307 | .Sp |
312 | .Sp |
308 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
313 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
309 | .IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4 |
314 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
310 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" |
315 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
311 | Sets the allocation function to use (the prototype and semantics are |
316 | Sets the allocation function to use (the prototype is similar \- the |
312 | identical to the realloc C function). It is used to allocate and free |
317 | semantics is identical \- to the realloc C function). It is used to |
313 | memory (no surprises here). If it returns zero when memory needs to be |
318 | allocate and free memory (no surprises here). If it returns zero when |
314 | allocated, the library might abort or take some potentially destructive |
319 | memory needs to be allocated, the library might abort or take some |
315 | action. The default is your system realloc function. |
320 | potentially destructive action. The default is your system realloc |
|
|
321 | function. |
316 | .Sp |
322 | .Sp |
317 | You could override this function in high-availability programs to, say, |
323 | You could override this function in high-availability programs to, say, |
318 | free some memory if it cannot allocate memory, to use a special allocator, |
324 | free some memory if it cannot allocate memory, to use a special allocator, |
319 | or even to sleep a while and retry until some memory is available. |
325 | or even to sleep a while and retry until some memory is available. |
320 | .Sp |
326 | .Sp |
… | |
… | |
409 | or setgid) then libev will \fInot\fR look at the environment variable |
415 | or setgid) then libev will \fInot\fR look at the environment variable |
410 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
416 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
411 | override the flags completely if it is found in the environment. This is |
417 | override the flags completely if it is found in the environment. This is |
412 | useful to try out specific backends to test their performance, or to work |
418 | useful to try out specific backends to test their performance, or to work |
413 | around bugs. |
419 | around bugs. |
|
|
420 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
|
|
421 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
|
|
422 | .IX Item "EVFLAG_FORKCHECK" |
|
|
423 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
|
|
424 | a fork, you can also make libev check for a fork in each iteration by |
|
|
425 | enabling this flag. |
|
|
426 | .Sp |
|
|
427 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
|
|
428 | and thus this might slow down your event loop if you do a lot of loop |
|
|
429 | iterations and little real work, but is usually not noticeable (on my |
|
|
430 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
|
|
431 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
|
|
432 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
|
|
433 | .Sp |
|
|
434 | The big advantage of this flag is that you can forget about fork (and |
|
|
435 | forget about forgetting to tell libev about forking) when you use this |
|
|
436 | flag. |
|
|
437 | .Sp |
|
|
438 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
|
|
439 | environment variable. |
414 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
440 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
415 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
441 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
416 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
442 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
417 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
443 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
418 | libev tries to roll its own fd_set with no limits on the number of fds, |
444 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
559 | .IP "ev_loop_fork (loop)" 4 |
585 | .IP "ev_loop_fork (loop)" 4 |
560 | .IX Item "ev_loop_fork (loop)" |
586 | .IX Item "ev_loop_fork (loop)" |
561 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
587 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
562 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
588 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
563 | after fork, and how you do this is entirely your own problem. |
589 | after fork, and how you do this is entirely your own problem. |
|
|
590 | .IP "unsigned int ev_loop_count (loop)" 4 |
|
|
591 | .IX Item "unsigned int ev_loop_count (loop)" |
|
|
592 | Returns the count of loop iterations for the loop, which is identical to |
|
|
593 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
|
|
594 | happily wraps around with enough iterations. |
|
|
595 | .Sp |
|
|
596 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
597 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
|
|
598 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
564 | .IP "unsigned int ev_backend (loop)" 4 |
599 | .IP "unsigned int ev_backend (loop)" 4 |
565 | .IX Item "unsigned int ev_backend (loop)" |
600 | .IX Item "unsigned int ev_backend (loop)" |
566 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
601 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
567 | use. |
602 | use. |
568 | .IP "ev_tstamp ev_now (loop)" 4 |
603 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
599 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
634 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
600 | usually a better approach for this kind of thing. |
635 | usually a better approach for this kind of thing. |
601 | .Sp |
636 | .Sp |
602 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
637 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
603 | .Sp |
638 | .Sp |
604 | .Vb 18 |
639 | .Vb 19 |
|
|
640 | \& - Before the first iteration, call any pending watchers. |
605 | \& * If there are no active watchers (reference count is zero), return. |
641 | \& * If there are no active watchers (reference count is zero), return. |
606 | \& - Queue prepare watchers and then call all outstanding watchers. |
642 | \& - Queue all prepare watchers and then call all outstanding watchers. |
607 | \& - If we have been forked, recreate the kernel state. |
643 | \& - If we have been forked, recreate the kernel state. |
608 | \& - Update the kernel state with all outstanding changes. |
644 | \& - Update the kernel state with all outstanding changes. |
609 | \& - Update the "event loop time". |
645 | \& - Update the "event loop time". |
610 | \& - Calculate for how long to block. |
646 | \& - Calculate for how long to block. |
611 | \& - Block the process, waiting for any events. |
647 | \& - Block the process, waiting for any events. |
… | |
… | |
854 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
890 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
855 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
891 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
856 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
892 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
857 | events but its callback has not yet been invoked). As long as a watcher |
893 | events but its callback has not yet been invoked). As long as a watcher |
858 | is pending (but not active) you must not call an init function on it (but |
894 | is pending (but not active) you must not call an init function on it (but |
859 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
895 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
860 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
896 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
897 | it). |
861 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
898 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
862 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
899 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
863 | Returns the callback currently set on the watcher. |
900 | Returns the callback currently set on the watcher. |
864 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
901 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
865 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
902 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
866 | Change the callback. You can change the callback at virtually any time |
903 | Change the callback. You can change the callback at virtually any time |
867 | (modulo threads). |
904 | (modulo threads). |
|
|
905 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
906 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
907 | .PD 0 |
|
|
908 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
909 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
910 | .PD |
|
|
911 | Set and query the priority of the watcher. The priority is a small |
|
|
912 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
913 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
914 | before watchers with lower priority, but priority will not keep watchers |
|
|
915 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
916 | .Sp |
|
|
917 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
918 | invocation after new events have been received. This is useful, for |
|
|
919 | example, to reduce latency after idling, or more often, to bind two |
|
|
920 | watchers on the same event and make sure one is called first. |
|
|
921 | .Sp |
|
|
922 | If you need to suppress invocation when higher priority events are pending |
|
|
923 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
924 | .Sp |
|
|
925 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
926 | pending. |
|
|
927 | .Sp |
|
|
928 | The default priority used by watchers when no priority has been set is |
|
|
929 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
930 | .Sp |
|
|
931 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
932 | fine, as long as you do not mind that the priority value you query might |
|
|
933 | or might not have been adjusted to be within valid range. |
|
|
934 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
935 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
936 | Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither |
|
|
937 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
938 | can deal with that fact. |
|
|
939 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
940 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
941 | If the watcher is pending, this function returns clears its pending status |
|
|
942 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
943 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
868 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
944 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
869 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
945 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
870 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
946 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
871 | and read at any time, libev will completely ignore it. This can be used |
947 | and read at any time, libev will completely ignore it. This can be used |
872 | to associate arbitrary data with your watcher. If you need more data and |
948 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
983 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1059 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
984 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1060 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
985 | .PP |
1061 | .PP |
986 | If you cannot run the fd in non-blocking mode (for example you should not |
1062 | If you cannot run the fd in non-blocking mode (for example you should not |
987 | play around with an Xlib connection), then you have to seperately re-test |
1063 | play around with an Xlib connection), then you have to seperately re-test |
988 | wether a file descriptor is really ready with a known-to-be good interface |
1064 | whether a file descriptor is really ready with a known-to-be good interface |
989 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1065 | such as poll (fortunately in our Xlib example, Xlib already does this on |
990 | its own, so its quite safe to use). |
1066 | its own, so its quite safe to use). |
991 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1067 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
992 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1068 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
993 | .PD 0 |
1069 | .PD 0 |
… | |
… | |
1069 | .IP "ev_timer_again (loop)" 4 |
1145 | .IP "ev_timer_again (loop)" 4 |
1070 | .IX Item "ev_timer_again (loop)" |
1146 | .IX Item "ev_timer_again (loop)" |
1071 | This will act as if the timer timed out and restart it again if it is |
1147 | This will act as if the timer timed out and restart it again if it is |
1072 | repeating. The exact semantics are: |
1148 | repeating. The exact semantics are: |
1073 | .Sp |
1149 | .Sp |
|
|
1150 | If the timer is pending, its pending status is cleared. |
|
|
1151 | .Sp |
1074 | If the timer is started but nonrepeating, stop it. |
1152 | If the timer is started but nonrepeating, stop it (as if it timed out). |
1075 | .Sp |
1153 | .Sp |
1076 | If the timer is repeating, either start it if necessary (with the repeat |
1154 | If the timer is repeating, either start it if necessary (with the |
1077 | value), or reset the running timer to the repeat value. |
1155 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1078 | .Sp |
1156 | .Sp |
1079 | This sounds a bit complicated, but here is a useful and typical |
1157 | This sounds a bit complicated, but here is a useful and typical |
1080 | example: Imagine you have a tcp connection and you want a so-called |
1158 | example: Imagine you have a tcp connection and you want a so-called idle |
1081 | idle timeout, that is, you want to be called when there have been, |
1159 | timeout, that is, you want to be called when there have been, say, 60 |
1082 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1160 | seconds of inactivity on the socket. The easiest way to do this is to |
1083 | this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling |
1161 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
1084 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1162 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1085 | you go into an idle state where you do not expect data to travel on the |
1163 | you go into an idle state where you do not expect data to travel on the |
1086 | socket, you can stop the timer, and again will automatically restart it if |
1164 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
1087 | need be. |
1165 | automatically restart it if need be. |
1088 | .Sp |
1166 | .Sp |
1089 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1167 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
1090 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
1168 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
1091 | .Sp |
1169 | .Sp |
1092 | .Vb 8 |
1170 | .Vb 8 |
1093 | \& ev_timer_init (timer, callback, 0., 5.); |
1171 | \& ev_timer_init (timer, callback, 0., 5.); |
1094 | \& ev_timer_again (loop, timer); |
1172 | \& ev_timer_again (loop, timer); |
1095 | \& ... |
1173 | \& ... |
… | |
… | |
1098 | \& ... |
1176 | \& ... |
1099 | \& timer->again = 10.; |
1177 | \& timer->again = 10.; |
1100 | \& ev_timer_again (loop, timer); |
1178 | \& ev_timer_again (loop, timer); |
1101 | .Ve |
1179 | .Ve |
1102 | .Sp |
1180 | .Sp |
1103 | This is more efficient then stopping/starting the timer eahc time you want |
1181 | This is more slightly efficient then stopping/starting the timer each time |
1104 | to modify its timeout value. |
1182 | you want to modify its timeout value. |
1105 | .IP "ev_tstamp repeat [read\-write]" 4 |
1183 | .IP "ev_tstamp repeat [read\-write]" 4 |
1106 | .IX Item "ev_tstamp repeat [read-write]" |
1184 | .IX Item "ev_tstamp repeat [read-write]" |
1107 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1185 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1108 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1186 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1109 | which is also when any modifications are taken into account. |
1187 | which is also when any modifications are taken into account. |
… | |
… | |
1157 | but on wallclock time (absolute time). You can tell a periodic watcher |
1235 | but on wallclock time (absolute time). You can tell a periodic watcher |
1158 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1236 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1159 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1237 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1160 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1238 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1161 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1239 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1162 | roughly 10 seconds later and of course not if you reset your system time |
1240 | roughly 10 seconds later). |
1163 | again). |
|
|
1164 | .PP |
1241 | .PP |
1165 | They can also be used to implement vastly more complex timers, such as |
1242 | They can also be used to implement vastly more complex timers, such as |
1166 | triggering an event on eahc midnight, local time. |
1243 | triggering an event on each midnight, local time or other, complicated, |
|
|
1244 | rules. |
1167 | .PP |
1245 | .PP |
1168 | As with timers, the callback is guarenteed to be invoked only when the |
1246 | As with timers, the callback is guarenteed to be invoked only when the |
1169 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1247 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1170 | during the same loop iteration then order of execution is undefined. |
1248 | during the same loop iteration then order of execution is undefined. |
1171 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1249 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
… | |
… | |
1175 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1253 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1176 | .PD |
1254 | .PD |
1177 | Lots of arguments, lets sort it out... There are basically three modes of |
1255 | Lots of arguments, lets sort it out... There are basically three modes of |
1178 | operation, and we will explain them from simplest to complex: |
1256 | operation, and we will explain them from simplest to complex: |
1179 | .RS 4 |
1257 | .RS 4 |
1180 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1258 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1181 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1259 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1182 | In this configuration the watcher triggers an event at the wallclock time |
1260 | In this configuration the watcher triggers an event at the wallclock time |
1183 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1261 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1184 | that is, if it is to be run at January 1st 2011 then it will run when the |
1262 | that is, if it is to be run at January 1st 2011 then it will run when the |
1185 | system time reaches or surpasses this time. |
1263 | system time reaches or surpasses this time. |
1186 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1264 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1187 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1265 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1188 | In this mode the watcher will always be scheduled to time out at the next |
1266 | In this mode the watcher will always be scheduled to time out at the next |
1189 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1267 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1190 | of any time jumps. |
1268 | and then repeat, regardless of any time jumps. |
1191 | .Sp |
1269 | .Sp |
1192 | This can be used to create timers that do not drift with respect to system |
1270 | This can be used to create timers that do not drift with respect to system |
1193 | time: |
1271 | time: |
1194 | .Sp |
1272 | .Sp |
1195 | .Vb 1 |
1273 | .Vb 1 |
… | |
… | |
1202 | by 3600. |
1280 | by 3600. |
1203 | .Sp |
1281 | .Sp |
1204 | Another way to think about it (for the mathematically inclined) is that |
1282 | Another way to think about it (for the mathematically inclined) is that |
1205 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1283 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1206 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1284 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1285 | .Sp |
|
|
1286 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1287 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1288 | this value. |
1207 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1289 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1208 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1290 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1209 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1291 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1210 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1292 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1211 | reschedule callback will be called with the watcher as first, and the |
1293 | reschedule callback will be called with the watcher as first, and the |
1212 | current time as second argument. |
1294 | current time as second argument. |
1213 | .Sp |
1295 | .Sp |
1214 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1296 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1215 | ever, or make any event loop modifications\fR. If you need to stop it, |
1297 | ever, or make any event loop modifications\fR. If you need to stop it, |
1216 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1298 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1217 | starting a prepare watcher). |
1299 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1218 | .Sp |
1300 | .Sp |
1219 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1301 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1220 | ev_tstamp now)\*(C'\fR, e.g.: |
1302 | ev_tstamp now)\*(C'\fR, e.g.: |
1221 | .Sp |
1303 | .Sp |
1222 | .Vb 4 |
1304 | .Vb 4 |
… | |
… | |
1246 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1328 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1247 | Simply stops and restarts the periodic watcher again. This is only useful |
1329 | Simply stops and restarts the periodic watcher again. This is only useful |
1248 | when you changed some parameters or the reschedule callback would return |
1330 | when you changed some parameters or the reschedule callback would return |
1249 | a different time than the last time it was called (e.g. in a crond like |
1331 | a different time than the last time it was called (e.g. in a crond like |
1250 | program when the crontabs have changed). |
1332 | program when the crontabs have changed). |
|
|
1333 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1334 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1335 | When repeating, this contains the offset value, otherwise this is the |
|
|
1336 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1337 | .Sp |
|
|
1338 | Can be modified any time, but changes only take effect when the periodic |
|
|
1339 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1251 | .IP "ev_tstamp interval [read\-write]" 4 |
1340 | .IP "ev_tstamp interval [read\-write]" 4 |
1252 | .IX Item "ev_tstamp interval [read-write]" |
1341 | .IX Item "ev_tstamp interval [read-write]" |
1253 | The current interval value. Can be modified any time, but changes only |
1342 | The current interval value. Can be modified any time, but changes only |
1254 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1343 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1255 | called. |
1344 | called. |
… | |
… | |
1382 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1471 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1383 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1472 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1384 | otherwise always forced to be at least one) and all the other fields of |
1473 | otherwise always forced to be at least one) and all the other fields of |
1385 | the stat buffer having unspecified contents. |
1474 | the stat buffer having unspecified contents. |
1386 | .PP |
1475 | .PP |
|
|
1476 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1477 | relative and your working directory changes, the behaviour is undefined. |
|
|
1478 | .PP |
1387 | Since there is no standard to do this, the portable implementation simply |
1479 | Since there is no standard to do this, the portable implementation simply |
1388 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
1480 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
1389 | can specify a recommended polling interval for this case. If you specify |
1481 | can specify a recommended polling interval for this case. If you specify |
1390 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1482 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1391 | unspecified default\fR value will be used (which you can expect to be around |
1483 | unspecified default\fR value will be used (which you can expect to be around |
… | |
… | |
1472 | \& ev_stat_start (loop, &passwd); |
1564 | \& ev_stat_start (loop, &passwd); |
1473 | .Ve |
1565 | .Ve |
1474 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1566 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1475 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1567 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1476 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1568 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1477 | Idle watchers trigger events when there are no other events are pending |
1569 | Idle watchers trigger events when no other events of the same or higher |
1478 | (prepare, check and other idle watchers do not count). That is, as long |
1570 | priority are pending (prepare, check and other idle watchers do not |
1479 | as your process is busy handling sockets or timeouts (or even signals, |
1571 | count). |
1480 | imagine) it will not be triggered. But when your process is idle all idle |
1572 | .PP |
1481 | watchers are being called again and again, once per event loop iteration \- |
1573 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1574 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1575 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1576 | are pending), the idle watchers are being called once per event loop |
1482 | until stopped, that is, or your process receives more events and becomes |
1577 | iteration \- until stopped, that is, or your process receives more events |
1483 | busy. |
1578 | and becomes busy again with higher priority stuff. |
1484 | .PP |
1579 | .PP |
1485 | The most noteworthy effect is that as long as any idle watchers are |
1580 | The most noteworthy effect is that as long as any idle watchers are |
1486 | active, the process will not block when waiting for new events. |
1581 | active, the process will not block when waiting for new events. |
1487 | .PP |
1582 | .PP |
1488 | Apart from keeping your process non-blocking (which is a useful |
1583 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1551 | are ready to run (it's actually more complicated: it only runs coroutines |
1646 | are ready to run (it's actually more complicated: it only runs coroutines |
1552 | with priority higher than or equal to the event loop and one coroutine |
1647 | with priority higher than or equal to the event loop and one coroutine |
1553 | of lower priority, but only once, using idle watchers to keep the event |
1648 | of lower priority, but only once, using idle watchers to keep the event |
1554 | loop from blocking if lower-priority coroutines are active, thus mapping |
1649 | loop from blocking if lower-priority coroutines are active, thus mapping |
1555 | low-priority coroutines to idle/background tasks). |
1650 | low-priority coroutines to idle/background tasks). |
|
|
1651 | .PP |
|
|
1652 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1653 | priority, to ensure that they are being run before any other watchers |
|
|
1654 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1655 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1656 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1657 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1658 | loops those other event loops might be in an unusable state until their |
|
|
1659 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1660 | others). |
1556 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1661 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1557 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1662 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1558 | .PD 0 |
1663 | .PD 0 |
1559 | .IP "ev_check_init (ev_check *, callback)" 4 |
1664 | .IP "ev_check_init (ev_check *, callback)" 4 |
1560 | .IX Item "ev_check_init (ev_check *, callback)" |
1665 | .IX Item "ev_check_init (ev_check *, callback)" |
1561 | .PD |
1666 | .PD |
1562 | Initialises and configures the prepare or check watcher \- they have no |
1667 | Initialises and configures the prepare or check watcher \- they have no |
1563 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1668 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1564 | macros, but using them is utterly, utterly and completely pointless. |
1669 | macros, but using them is utterly, utterly and completely pointless. |
1565 | .PP |
1670 | .PP |
1566 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1671 | There are a number of principal ways to embed other event loops or modules |
1567 | and a timeout watcher in a prepare handler, as required by libadns, and |
1672 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1673 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1674 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1675 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1676 | into the Glib event loop). |
|
|
1677 | .PP |
|
|
1678 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1568 | in a check watcher, destroy them and call into libadns. What follows is |
1679 | and in a check watcher, destroy them and call into libadns. What follows |
1569 | pseudo-code only of course: |
1680 | is pseudo-code only of course. This requires you to either use a low |
|
|
1681 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1682 | the callbacks for the IO/timeout watchers might not have been called yet. |
1570 | .PP |
1683 | .PP |
1571 | .Vb 2 |
1684 | .Vb 2 |
1572 | \& static ev_io iow [nfd]; |
1685 | \& static ev_io iow [nfd]; |
1573 | \& static ev_timer tw; |
1686 | \& static ev_timer tw; |
1574 | .Ve |
1687 | .Ve |
1575 | .PP |
1688 | .PP |
1576 | .Vb 9 |
1689 | .Vb 4 |
1577 | \& static void |
1690 | \& static void |
1578 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1691 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1579 | \& { |
1692 | \& { |
1580 | \& // set the relevant poll flags |
|
|
1581 | \& // could also call adns_processreadable etc. here |
|
|
1582 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1583 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1584 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1585 | \& } |
1693 | \& } |
1586 | .Ve |
1694 | .Ve |
1587 | .PP |
1695 | .PP |
1588 | .Vb 7 |
1696 | .Vb 8 |
1589 | \& // create io watchers for each fd and a timer before blocking |
1697 | \& // create io watchers for each fd and a timer before blocking |
1590 | \& static void |
1698 | \& static void |
1591 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1699 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1592 | \& { |
1700 | \& { |
1593 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1701 | \& int timeout = 3600000; |
|
|
1702 | \& struct pollfd fds [nfd]; |
1594 | \& // actual code will need to loop here and realloc etc. |
1703 | \& // actual code will need to loop here and realloc etc. |
1595 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1704 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1596 | .Ve |
1705 | .Ve |
1597 | .PP |
1706 | .PP |
1598 | .Vb 3 |
1707 | .Vb 3 |
… | |
… | |
1600 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1709 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1601 | \& ev_timer_start (loop, &tw); |
1710 | \& ev_timer_start (loop, &tw); |
1602 | .Ve |
1711 | .Ve |
1603 | .PP |
1712 | .PP |
1604 | .Vb 6 |
1713 | .Vb 6 |
1605 | \& // create on ev_io per pollfd |
1714 | \& // create one ev_io per pollfd |
1606 | \& for (int i = 0; i < nfd; ++i) |
1715 | \& for (int i = 0; i < nfd; ++i) |
1607 | \& { |
1716 | \& { |
1608 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1717 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1609 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1718 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1610 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1719 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1611 | .Ve |
1720 | .Ve |
1612 | .PP |
1721 | .PP |
1613 | .Vb 5 |
1722 | .Vb 4 |
1614 | \& fds [i].revents = 0; |
1723 | \& fds [i].revents = 0; |
1615 | \& iow [i].data = fds + i; |
|
|
1616 | \& ev_io_start (loop, iow + i); |
1724 | \& ev_io_start (loop, iow + i); |
1617 | \& } |
1725 | \& } |
1618 | \& } |
1726 | \& } |
1619 | .Ve |
1727 | .Ve |
1620 | .PP |
1728 | .PP |
… | |
… | |
1624 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1732 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1625 | \& { |
1733 | \& { |
1626 | \& ev_timer_stop (loop, &tw); |
1734 | \& ev_timer_stop (loop, &tw); |
1627 | .Ve |
1735 | .Ve |
1628 | .PP |
1736 | .PP |
1629 | .Vb 2 |
1737 | .Vb 8 |
1630 | \& for (int i = 0; i < nfd; ++i) |
1738 | \& for (int i = 0; i < nfd; ++i) |
|
|
1739 | \& { |
|
|
1740 | \& // set the relevant poll flags |
|
|
1741 | \& // could also call adns_processreadable etc. here |
|
|
1742 | \& struct pollfd *fd = fds + i; |
|
|
1743 | \& int revents = ev_clear_pending (iow + i); |
|
|
1744 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1745 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1746 | .Ve |
|
|
1747 | .PP |
|
|
1748 | .Vb 3 |
|
|
1749 | \& // now stop the watcher |
1631 | \& ev_io_stop (loop, iow + i); |
1750 | \& ev_io_stop (loop, iow + i); |
|
|
1751 | \& } |
1632 | .Ve |
1752 | .Ve |
1633 | .PP |
1753 | .PP |
1634 | .Vb 2 |
1754 | .Vb 2 |
1635 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1755 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1756 | \& } |
|
|
1757 | .Ve |
|
|
1758 | .PP |
|
|
1759 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1760 | in the prepare watcher and would dispose of the check watcher. |
|
|
1761 | .PP |
|
|
1762 | Method 3: If the module to be embedded supports explicit event |
|
|
1763 | notification (adns does), you can also make use of the actual watcher |
|
|
1764 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1765 | .PP |
|
|
1766 | .Vb 5 |
|
|
1767 | \& static void |
|
|
1768 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1769 | \& { |
|
|
1770 | \& adns_state ads = (adns_state)w->data; |
|
|
1771 | \& update_now (EV_A); |
|
|
1772 | .Ve |
|
|
1773 | .PP |
|
|
1774 | .Vb 2 |
|
|
1775 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1776 | \& } |
|
|
1777 | .Ve |
|
|
1778 | .PP |
|
|
1779 | .Vb 5 |
|
|
1780 | \& static void |
|
|
1781 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1782 | \& { |
|
|
1783 | \& adns_state ads = (adns_state)w->data; |
|
|
1784 | \& update_now (EV_A); |
|
|
1785 | .Ve |
|
|
1786 | .PP |
|
|
1787 | .Vb 3 |
|
|
1788 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1789 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1790 | \& } |
|
|
1791 | .Ve |
|
|
1792 | .PP |
|
|
1793 | .Vb 1 |
|
|
1794 | \& // do not ever call adns_afterpoll |
|
|
1795 | .Ve |
|
|
1796 | .PP |
|
|
1797 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1798 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1799 | their poll function. The drawback with this solution is that the main |
|
|
1800 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1801 | this. |
|
|
1802 | .PP |
|
|
1803 | .Vb 4 |
|
|
1804 | \& static gint |
|
|
1805 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1806 | \& { |
|
|
1807 | \& int got_events = 0; |
|
|
1808 | .Ve |
|
|
1809 | .PP |
|
|
1810 | .Vb 2 |
|
|
1811 | \& for (n = 0; n < nfds; ++n) |
|
|
1812 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1813 | .Ve |
|
|
1814 | .PP |
|
|
1815 | .Vb 2 |
|
|
1816 | \& if (timeout >= 0) |
|
|
1817 | \& // create/start timer |
|
|
1818 | .Ve |
|
|
1819 | .PP |
|
|
1820 | .Vb 2 |
|
|
1821 | \& // poll |
|
|
1822 | \& ev_loop (EV_A_ 0); |
|
|
1823 | .Ve |
|
|
1824 | .PP |
|
|
1825 | .Vb 3 |
|
|
1826 | \& // stop timer again |
|
|
1827 | \& if (timeout >= 0) |
|
|
1828 | \& ev_timer_stop (EV_A_ &to); |
|
|
1829 | .Ve |
|
|
1830 | .PP |
|
|
1831 | .Vb 3 |
|
|
1832 | \& // stop io watchers again - their callbacks should have set |
|
|
1833 | \& for (n = 0; n < nfds; ++n) |
|
|
1834 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1835 | .Ve |
|
|
1836 | .PP |
|
|
1837 | .Vb 2 |
|
|
1838 | \& return got_events; |
1636 | \& } |
1839 | \& } |
1637 | .Ve |
1840 | .Ve |
1638 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1841 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1639 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1842 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1640 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1843 | .IX Subsection "ev_embed - when one backend isn't enough..." |
… | |
… | |
1824 | .PP |
2027 | .PP |
1825 | .Vb 1 |
2028 | .Vb 1 |
1826 | \& #include <ev++.h> |
2029 | \& #include <ev++.h> |
1827 | .Ve |
2030 | .Ve |
1828 | .PP |
2031 | .PP |
1829 | (it is not installed by default). This automatically includes \fIev.h\fR |
2032 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1830 | and puts all of its definitions (many of them macros) into the global |
2033 | of them macros) into the global namespace. All \*(C+ specific things are |
1831 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2034 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2035 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1832 | .PP |
2036 | .PP |
1833 | It should support all the same embedding options as \fIev.h\fR, most notably |
2037 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1834 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2038 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2039 | that the watcher is associated with (or no additional members at all if |
|
|
2040 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2041 | .PP |
|
|
2042 | Currently, functions, and static and non-static member functions can be |
|
|
2043 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2044 | need one additional pointer for context. If you need support for other |
|
|
2045 | types of functors please contact the author (preferably after implementing |
|
|
2046 | it). |
1835 | .PP |
2047 | .PP |
1836 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2048 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1837 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2049 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1838 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2050 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1839 | .IX Item "ev::READ, ev::WRITE etc." |
2051 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1851 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2063 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1852 | defines by many implementations. |
2064 | defines by many implementations. |
1853 | .Sp |
2065 | .Sp |
1854 | All of those classes have these methods: |
2066 | All of those classes have these methods: |
1855 | .RS 4 |
2067 | .RS 4 |
1856 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2068 | .IP "ev::TYPE::TYPE ()" 4 |
1857 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2069 | .IX Item "ev::TYPE::TYPE ()" |
1858 | .PD 0 |
2070 | .PD 0 |
1859 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2071 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1860 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2072 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1861 | .IP "ev::TYPE::~TYPE" 4 |
2073 | .IP "ev::TYPE::~TYPE" 4 |
1862 | .IX Item "ev::TYPE::~TYPE" |
2074 | .IX Item "ev::TYPE::~TYPE" |
1863 | .PD |
2075 | .PD |
1864 | The constructor takes a pointer to an object and a method pointer to |
2076 | The constructor (optionally) takes an event loop to associate the watcher |
1865 | the event handler callback to call in this class. The constructor calls |
2077 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1866 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2078 | .Sp |
1867 | before starting it. If you do not specify a loop then the constructor |
2079 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1868 | automatically associates the default loop with this watcher. |
2080 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2081 | .Sp |
|
|
2082 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2083 | method to set a callback before you can start the watcher. |
|
|
2084 | .Sp |
|
|
2085 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2086 | not allow explicit template arguments for constructors). |
1869 | .Sp |
2087 | .Sp |
1870 | The destructor automatically stops the watcher if it is active. |
2088 | The destructor automatically stops the watcher if it is active. |
|
|
2089 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2090 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2091 | This method sets the callback method to call. The method has to have a |
|
|
2092 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2093 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2094 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2095 | .Sp |
|
|
2096 | This method synthesizes efficient thunking code to call your method from |
|
|
2097 | the C callback that libev requires. If your compiler can inline your |
|
|
2098 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2099 | your compiler is good :), then the method will be fully inlined into the |
|
|
2100 | thunking function, making it as fast as a direct C callback. |
|
|
2101 | .Sp |
|
|
2102 | Example: simple class declaration and watcher initialisation |
|
|
2103 | .Sp |
|
|
2104 | .Vb 4 |
|
|
2105 | \& struct myclass |
|
|
2106 | \& { |
|
|
2107 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2108 | \& } |
|
|
2109 | .Ve |
|
|
2110 | .Sp |
|
|
2111 | .Vb 3 |
|
|
2112 | \& myclass obj; |
|
|
2113 | \& ev::io iow; |
|
|
2114 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2115 | .Ve |
|
|
2116 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2117 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2118 | Also sets a callback, but uses a static method or plain function as |
|
|
2119 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2120 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2121 | .Sp |
|
|
2122 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2123 | .Sp |
|
|
2124 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2125 | .Sp |
|
|
2126 | Example: |
|
|
2127 | .Sp |
|
|
2128 | .Vb 2 |
|
|
2129 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2130 | \& iow.set <io_cb> (); |
|
|
2131 | .Ve |
1871 | .IP "w\->set (struct ev_loop *)" 4 |
2132 | .IP "w\->set (struct ev_loop *)" 4 |
1872 | .IX Item "w->set (struct ev_loop *)" |
2133 | .IX Item "w->set (struct ev_loop *)" |
1873 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2134 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1874 | do this when the watcher is inactive (and not pending either). |
2135 | do this when the watcher is inactive (and not pending either). |
1875 | .IP "w\->set ([args])" 4 |
2136 | .IP "w\->set ([args])" 4 |
1876 | .IX Item "w->set ([args])" |
2137 | .IX Item "w->set ([args])" |
1877 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2138 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1878 | called at least once. Unlike the C counterpart, an active watcher gets |
2139 | called at least once. Unlike the C counterpart, an active watcher gets |
1879 | automatically stopped and restarted. |
2140 | automatically stopped and restarted when reconfiguring it with this |
|
|
2141 | method. |
1880 | .IP "w\->start ()" 4 |
2142 | .IP "w\->start ()" 4 |
1881 | .IX Item "w->start ()" |
2143 | .IX Item "w->start ()" |
1882 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2144 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1883 | constructor already takes the loop. |
2145 | constructor already stores the event loop. |
1884 | .IP "w\->stop ()" 4 |
2146 | .IP "w\->stop ()" 4 |
1885 | .IX Item "w->stop ()" |
2147 | .IX Item "w->stop ()" |
1886 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2148 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1887 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2149 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1888 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2150 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1914 | .Vb 2 |
2176 | .Vb 2 |
1915 | \& myclass (); |
2177 | \& myclass (); |
1916 | \& } |
2178 | \& } |
1917 | .Ve |
2179 | .Ve |
1918 | .PP |
2180 | .PP |
1919 | .Vb 6 |
2181 | .Vb 4 |
1920 | \& myclass::myclass (int fd) |
2182 | \& myclass::myclass (int fd) |
1921 | \& : io (this, &myclass::io_cb), |
|
|
1922 | \& idle (this, &myclass::idle_cb) |
|
|
1923 | \& { |
2183 | \& { |
|
|
2184 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2185 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2186 | .Ve |
|
|
2187 | .PP |
|
|
2188 | .Vb 2 |
1924 | \& io.start (fd, ev::READ); |
2189 | \& io.start (fd, ev::READ); |
1925 | \& } |
2190 | \& } |
1926 | .Ve |
2191 | .Ve |
1927 | .SH "MACRO MAGIC" |
2192 | .SH "MACRO MAGIC" |
1928 | .IX Header "MACRO MAGIC" |
2193 | .IX Header "MACRO MAGIC" |
1929 | Libev can be compiled with a variety of options, the most fundemantal is |
2194 | Libev can be compiled with a variety of options, the most fundemantal is |
1930 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
2195 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
1931 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2196 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1932 | .PP |
2197 | .PP |
1933 | To make it easier to write programs that cope with either variant, the |
2198 | To make it easier to write programs that cope with either variant, the |
1934 | following macros are defined: |
2199 | following macros are defined: |
1935 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2200 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
… | |
… | |
1970 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
2235 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1971 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2236 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1972 | Similar to the other two macros, this gives you the value of the default |
2237 | Similar to the other two macros, this gives you the value of the default |
1973 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
2238 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
1974 | .PP |
2239 | .PP |
1975 | Example: Declare and initialise a check watcher, working regardless of |
2240 | Example: Declare and initialise a check watcher, utilising the above |
1976 | wether multiple loops are supported or not. |
2241 | macros so it will work regardless of whether multiple loops are supported |
|
|
2242 | or not. |
1977 | .PP |
2243 | .PP |
1978 | .Vb 5 |
2244 | .Vb 5 |
1979 | \& static void |
2245 | \& static void |
1980 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2246 | \& check_cb (EV_P_ ev_timer *w, int revents) |
1981 | \& { |
2247 | \& { |
… | |
… | |
2044 | .Vb 1 |
2310 | .Vb 1 |
2045 | \& ev_win32.c required on win32 platforms only |
2311 | \& ev_win32.c required on win32 platforms only |
2046 | .Ve |
2312 | .Ve |
2047 | .PP |
2313 | .PP |
2048 | .Vb 5 |
2314 | .Vb 5 |
2049 | \& ev_select.c only when select backend is enabled (which is by default) |
2315 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
2050 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2316 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2051 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2317 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2052 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2318 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2053 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2319 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2054 | .Ve |
2320 | .Ve |
… | |
… | |
2207 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2473 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2208 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2474 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2209 | additional independent event loops. Otherwise there will be no support |
2475 | additional independent event loops. Otherwise there will be no support |
2210 | for multiple event loops and there is no first event loop pointer |
2476 | for multiple event loops and there is no first event loop pointer |
2211 | argument. Instead, all functions act on the single default loop. |
2477 | argument. Instead, all functions act on the single default loop. |
|
|
2478 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2479 | .IX Item "EV_MINPRI" |
|
|
2480 | .PD 0 |
|
|
2481 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2482 | .IX Item "EV_MAXPRI" |
|
|
2483 | .PD |
|
|
2484 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2485 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2486 | provide for more priorities by overriding those symbols (usually defined |
|
|
2487 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2488 | .Sp |
|
|
2489 | When doing priority-based operations, libev usually has to linearly search |
|
|
2490 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2491 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2492 | fine. |
|
|
2493 | .Sp |
|
|
2494 | If your embedding app does not need any priorities, defining these both to |
|
|
2495 | \&\f(CW0\fR will save some memory and cpu. |
2212 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2496 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2213 | .IX Item "EV_PERIODIC_ENABLE" |
2497 | .IX Item "EV_PERIODIC_ENABLE" |
2214 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2498 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2499 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2500 | code. |
|
|
2501 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2502 | .IX Item "EV_IDLE_ENABLE" |
|
|
2503 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
2215 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2504 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2216 | code. |
2505 | code. |
2217 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2506 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2218 | .IX Item "EV_EMBED_ENABLE" |
2507 | .IX Item "EV_EMBED_ENABLE" |
2219 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2508 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
… | |
… | |
2281 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2570 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2282 | will be compiled. It is pretty complex because it provides its own header |
2571 | will be compiled. It is pretty complex because it provides its own header |
2283 | file. |
2572 | file. |
2284 | .Sp |
2573 | .Sp |
2285 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2574 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2286 | that everybody includes and which overrides some autoconf choices: |
2575 | that everybody includes and which overrides some configure choices: |
2287 | .Sp |
2576 | .Sp |
2288 | .Vb 4 |
2577 | .Vb 9 |
|
|
2578 | \& #define EV_MINIMAL 1 |
2289 | \& #define EV_USE_POLL 0 |
2579 | \& #define EV_USE_POLL 0 |
2290 | \& #define EV_MULTIPLICITY 0 |
2580 | \& #define EV_MULTIPLICITY 0 |
2291 | \& #define EV_PERIODICS 0 |
2581 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2582 | \& #define EV_STAT_ENABLE 0 |
|
|
2583 | \& #define EV_FORK_ENABLE 0 |
2292 | \& #define EV_CONFIG_H <config.h> |
2584 | \& #define EV_CONFIG_H <config.h> |
|
|
2585 | \& #define EV_MINPRI 0 |
|
|
2586 | \& #define EV_MAXPRI 0 |
2293 | .Ve |
2587 | .Ve |
2294 | .Sp |
2588 | .Sp |
2295 | .Vb 1 |
2589 | .Vb 1 |
2296 | \& #include "ev++.h" |
2590 | \& #include "ev++.h" |
2297 | .Ve |
2591 | .Ve |
… | |
… | |
2305 | .SH "COMPLEXITIES" |
2599 | .SH "COMPLEXITIES" |
2306 | .IX Header "COMPLEXITIES" |
2600 | .IX Header "COMPLEXITIES" |
2307 | In this section the complexities of (many of) the algorithms used inside |
2601 | In this section the complexities of (many of) the algorithms used inside |
2308 | libev will be explained. For complexity discussions about backends see the |
2602 | libev will be explained. For complexity discussions about backends see the |
2309 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2603 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2604 | .Sp |
|
|
2605 | All of the following are about amortised time: If an array needs to be |
|
|
2606 | extended, libev needs to realloc and move the whole array, but this |
|
|
2607 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2608 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2609 | it is much faster and asymptotically approaches constant time. |
2310 | .RS 4 |
2610 | .RS 4 |
2311 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2611 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2312 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2612 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2313 | .PD 0 |
2613 | This means that, when you have a watcher that triggers in one hour and |
|
|
2614 | there are 100 watchers that would trigger before that then inserting will |
|
|
2615 | have to skip those 100 watchers. |
2314 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2616 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2315 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2617 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2618 | That means that for changing a timer costs less than removing/adding them |
|
|
2619 | as only the relative motion in the event queue has to be paid for. |
2316 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2620 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2317 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2621 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2318 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2622 | These just add the watcher into an array or at the head of a list. |
2319 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2623 | =item Stopping check/prepare/idle watchers: O(1) |
2320 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2624 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2321 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2625 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2626 | These watchers are stored in lists then need to be walked to find the |
|
|
2627 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2628 | have many watchers waiting for the same fd or signal). |
2322 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2629 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2323 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2630 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2631 | .PD 0 |
2324 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2632 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2325 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2633 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2634 | .PD |
|
|
2635 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2636 | libev to recalculate its status (and possibly tell the kernel). |
2326 | .IP "Activating one watcher: O(1)" 4 |
2637 | .IP "Activating one watcher: O(1)" 4 |
2327 | .IX Item "Activating one watcher: O(1)" |
2638 | .IX Item "Activating one watcher: O(1)" |
|
|
2639 | .PD 0 |
|
|
2640 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2641 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2642 | .PD |
|
|
2643 | Priorities are implemented by allocating some space for each |
|
|
2644 | priority. When doing priority-based operations, libev usually has to |
|
|
2645 | linearly search all the priorities. |
2328 | .RE |
2646 | .RE |
2329 | .RS 4 |
2647 | .RS 4 |
2330 | .PD |
|
|
2331 | .SH "AUTHOR" |
2648 | .SH "AUTHOR" |
2332 | .IX Header "AUTHOR" |
2649 | .IX Header "AUTHOR" |
2333 | Marc Lehmann <libev@schmorp.de>. |
2650 | Marc Lehmann <libev@schmorp.de>. |