… | |
… | |
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 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-08" "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 |
… | |
… | |
854 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
889 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
855 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
890 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
856 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
891 | 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 |
892 | 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 |
893 | 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 |
894 | \&\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). |
895 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
896 | it). |
861 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
897 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
862 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
898 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
863 | Returns the callback currently set on the watcher. |
899 | Returns the callback currently set on the watcher. |
864 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
900 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
865 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
901 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
866 | Change the callback. You can change the callback at virtually any time |
902 | Change the callback. You can change the callback at virtually any time |
867 | (modulo threads). |
903 | (modulo threads). |
|
|
904 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
905 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
906 | .PD 0 |
|
|
907 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
908 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
909 | .PD |
|
|
910 | Set and query the priority of the watcher. The priority is a small |
|
|
911 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
912 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
913 | before watchers with lower priority, but priority will not keep watchers |
|
|
914 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
915 | .Sp |
|
|
916 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
917 | invocation after new events have been received. This is useful, for |
|
|
918 | example, to reduce latency after idling, or more often, to bind two |
|
|
919 | watchers on the same event and make sure one is called first. |
|
|
920 | .Sp |
|
|
921 | If you need to suppress invocation when higher priority events are pending |
|
|
922 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
923 | .Sp |
|
|
924 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
925 | pending. |
|
|
926 | .Sp |
|
|
927 | The default priority used by watchers when no priority has been set is |
|
|
928 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
929 | .Sp |
|
|
930 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
931 | fine, as long as you do not mind that the priority value you query might |
|
|
932 | or might not have been adjusted to be within valid range. |
|
|
933 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
934 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
935 | 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 |
|
|
936 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
937 | can deal with that fact. |
|
|
938 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
939 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
940 | If the watcher is pending, this function returns clears its pending status |
|
|
941 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
942 | 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" |
943 | .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" |
944 | .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 |
945 | 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 |
946 | 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 |
947 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
893 | \& struct my_io *w = (struct my_io *)w_; |
968 | \& struct my_io *w = (struct my_io *)w_; |
894 | \& ... |
969 | \& ... |
895 | \& } |
970 | \& } |
896 | .Ve |
971 | .Ve |
897 | .PP |
972 | .PP |
898 | More interesting and less C\-conformant ways of catsing your callback type |
973 | More interesting and less C\-conformant ways of casting your callback type |
899 | have been omitted.... |
974 | instead have been omitted. |
|
|
975 | .PP |
|
|
976 | Another common scenario is having some data structure with multiple |
|
|
977 | watchers: |
|
|
978 | .PP |
|
|
979 | .Vb 6 |
|
|
980 | \& struct my_biggy |
|
|
981 | \& { |
|
|
982 | \& int some_data; |
|
|
983 | \& ev_timer t1; |
|
|
984 | \& ev_timer t2; |
|
|
985 | \& } |
|
|
986 | .Ve |
|
|
987 | .PP |
|
|
988 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
989 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
990 | .PP |
|
|
991 | .Vb 1 |
|
|
992 | \& #include <stddef.h> |
|
|
993 | .Ve |
|
|
994 | .PP |
|
|
995 | .Vb 6 |
|
|
996 | \& static void |
|
|
997 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
998 | \& { |
|
|
999 | \& struct my_biggy big = (struct my_biggy * |
|
|
1000 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
1001 | \& } |
|
|
1002 | .Ve |
|
|
1003 | .PP |
|
|
1004 | .Vb 6 |
|
|
1005 | \& static void |
|
|
1006 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1007 | \& { |
|
|
1008 | \& struct my_biggy big = (struct my_biggy * |
|
|
1009 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
1010 | \& } |
|
|
1011 | .Ve |
900 | .SH "WATCHER TYPES" |
1012 | .SH "WATCHER TYPES" |
901 | .IX Header "WATCHER TYPES" |
1013 | .IX Header "WATCHER TYPES" |
902 | This section describes each watcher in detail, but will not repeat |
1014 | This section describes each watcher in detail, but will not repeat |
903 | information given in the last section. Any initialisation/set macros, |
1015 | information given in the last section. Any initialisation/set macros, |
904 | functions and members specific to the watcher type are explained. |
1016 | functions and members specific to the watcher type are explained. |
… | |
… | |
946 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1058 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
947 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1059 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
948 | .PP |
1060 | .PP |
949 | If you cannot run the fd in non-blocking mode (for example you should not |
1061 | If you cannot run the fd in non-blocking mode (for example you should not |
950 | play around with an Xlib connection), then you have to seperately re-test |
1062 | play around with an Xlib connection), then you have to seperately re-test |
951 | wether a file descriptor is really ready with a known-to-be good interface |
1063 | whether a file descriptor is really ready with a known-to-be good interface |
952 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1064 | such as poll (fortunately in our Xlib example, Xlib already does this on |
953 | its own, so its quite safe to use). |
1065 | its own, so its quite safe to use). |
954 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1066 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
955 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1067 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
956 | .PD 0 |
1068 | .PD 0 |
… | |
… | |
1032 | .IP "ev_timer_again (loop)" 4 |
1144 | .IP "ev_timer_again (loop)" 4 |
1033 | .IX Item "ev_timer_again (loop)" |
1145 | .IX Item "ev_timer_again (loop)" |
1034 | This will act as if the timer timed out and restart it again if it is |
1146 | This will act as if the timer timed out and restart it again if it is |
1035 | repeating. The exact semantics are: |
1147 | repeating. The exact semantics are: |
1036 | .Sp |
1148 | .Sp |
|
|
1149 | If the timer is pending, its pending status is cleared. |
|
|
1150 | .Sp |
1037 | If the timer is started but nonrepeating, stop it. |
1151 | If the timer is started but nonrepeating, stop it (as if it timed out). |
1038 | .Sp |
1152 | .Sp |
1039 | If the timer is repeating, either start it if necessary (with the repeat |
1153 | If the timer is repeating, either start it if necessary (with the |
1040 | value), or reset the running timer to the repeat value. |
1154 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1041 | .Sp |
1155 | .Sp |
1042 | This sounds a bit complicated, but here is a useful and typical |
1156 | This sounds a bit complicated, but here is a useful and typical |
1043 | example: Imagine you have a tcp connection and you want a so-called |
1157 | example: Imagine you have a tcp connection and you want a so-called idle |
1044 | idle timeout, that is, you want to be called when there have been, |
1158 | timeout, that is, you want to be called when there have been, say, 60 |
1045 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1159 | seconds of inactivity on the socket. The easiest way to do this is to |
1046 | 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 |
1160 | 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 |
1047 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1161 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1048 | you go into an idle state where you do not expect data to travel on the |
1162 | you go into an idle state where you do not expect data to travel on the |
1049 | socket, you can stop the timer, and again will automatically restart it if |
1163 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
1050 | need be. |
1164 | automatically restart it if need be. |
1051 | .Sp |
1165 | .Sp |
1052 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1166 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
1053 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
1167 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
1054 | .Sp |
1168 | .Sp |
1055 | .Vb 8 |
1169 | .Vb 8 |
1056 | \& ev_timer_init (timer, callback, 0., 5.); |
1170 | \& ev_timer_init (timer, callback, 0., 5.); |
1057 | \& ev_timer_again (loop, timer); |
1171 | \& ev_timer_again (loop, timer); |
1058 | \& ... |
1172 | \& ... |
… | |
… | |
1061 | \& ... |
1175 | \& ... |
1062 | \& timer->again = 10.; |
1176 | \& timer->again = 10.; |
1063 | \& ev_timer_again (loop, timer); |
1177 | \& ev_timer_again (loop, timer); |
1064 | .Ve |
1178 | .Ve |
1065 | .Sp |
1179 | .Sp |
1066 | This is more efficient then stopping/starting the timer eahc time you want |
1180 | This is more slightly efficient then stopping/starting the timer each time |
1067 | to modify its timeout value. |
1181 | you want to modify its timeout value. |
1068 | .IP "ev_tstamp repeat [read\-write]" 4 |
1182 | .IP "ev_tstamp repeat [read\-write]" 4 |
1069 | .IX Item "ev_tstamp repeat [read-write]" |
1183 | .IX Item "ev_tstamp repeat [read-write]" |
1070 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1184 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1071 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1185 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1072 | which is also when any modifications are taken into account. |
1186 | which is also when any modifications are taken into account. |
… | |
… | |
1345 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1459 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1346 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1460 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1347 | otherwise always forced to be at least one) and all the other fields of |
1461 | otherwise always forced to be at least one) and all the other fields of |
1348 | the stat buffer having unspecified contents. |
1462 | the stat buffer having unspecified contents. |
1349 | .PP |
1463 | .PP |
|
|
1464 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1465 | relative and your working directory changes, the behaviour is undefined. |
|
|
1466 | .PP |
1350 | Since there is no standard to do this, the portable implementation simply |
1467 | Since there is no standard to do this, the portable implementation simply |
1351 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
1468 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
1352 | can specify a recommended polling interval for this case. If you specify |
1469 | can specify a recommended polling interval for this case. If you specify |
1353 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1470 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1354 | unspecified default\fR value will be used (which you can expect to be around |
1471 | unspecified default\fR value will be used (which you can expect to be around |
1355 | five seconds, although this might change dynamically). Libev will also |
1472 | five seconds, although this might change dynamically). Libev will also |
1356 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
1473 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
… | |
… | |
1358 | .PP |
1475 | .PP |
1359 | This watcher type is not meant for massive numbers of stat watchers, |
1476 | This watcher type is not meant for massive numbers of stat watchers, |
1360 | as even with OS-supported change notifications, this can be |
1477 | as even with OS-supported change notifications, this can be |
1361 | resource\-intensive. |
1478 | resource\-intensive. |
1362 | .PP |
1479 | .PP |
1363 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
1480 | At the time of this writing, only the Linux inotify interface is |
1364 | if demand increases, at least a kqueue and inotify backend will be added. |
1481 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1482 | reader). Inotify will be used to give hints only and should not change the |
|
|
1483 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1484 | to fall back to regular polling again even with inotify, but changes are |
|
|
1485 | usually detected immediately, and if the file exists there will be no |
|
|
1486 | polling. |
1365 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1487 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1366 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1488 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1367 | .PD 0 |
1489 | .PD 0 |
1368 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1490 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1369 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1491 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
1430 | \& ev_stat_start (loop, &passwd); |
1552 | \& ev_stat_start (loop, &passwd); |
1431 | .Ve |
1553 | .Ve |
1432 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1554 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1433 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1555 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1434 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1556 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1435 | Idle watchers trigger events when there are no other events are pending |
1557 | Idle watchers trigger events when no other events of the same or higher |
1436 | (prepare, check and other idle watchers do not count). That is, as long |
1558 | priority are pending (prepare, check and other idle watchers do not |
1437 | as your process is busy handling sockets or timeouts (or even signals, |
1559 | count). |
1438 | imagine) it will not be triggered. But when your process is idle all idle |
1560 | .PP |
1439 | watchers are being called again and again, once per event loop iteration \- |
1561 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1562 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1563 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1564 | are pending), the idle watchers are being called once per event loop |
1440 | until stopped, that is, or your process receives more events and becomes |
1565 | iteration \- until stopped, that is, or your process receives more events |
1441 | busy. |
1566 | and becomes busy again with higher priority stuff. |
1442 | .PP |
1567 | .PP |
1443 | The most noteworthy effect is that as long as any idle watchers are |
1568 | The most noteworthy effect is that as long as any idle watchers are |
1444 | active, the process will not block when waiting for new events. |
1569 | active, the process will not block when waiting for new events. |
1445 | .PP |
1570 | .PP |
1446 | Apart from keeping your process non-blocking (which is a useful |
1571 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1541 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1666 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1542 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1667 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1543 | \& } |
1668 | \& } |
1544 | .Ve |
1669 | .Ve |
1545 | .PP |
1670 | .PP |
1546 | .Vb 7 |
1671 | .Vb 8 |
1547 | \& // create io watchers for each fd and a timer before blocking |
1672 | \& // create io watchers for each fd and a timer before blocking |
1548 | \& static void |
1673 | \& static void |
1549 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1674 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1550 | \& { |
1675 | \& { |
1551 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1676 | \& int timeout = 3600000; |
|
|
1677 | \& struct pollfd fds [nfd]; |
1552 | \& // actual code will need to loop here and realloc etc. |
1678 | \& // actual code will need to loop here and realloc etc. |
1553 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1679 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1554 | .Ve |
1680 | .Ve |
1555 | .PP |
1681 | .PP |
1556 | .Vb 3 |
1682 | .Vb 3 |
… | |
… | |
1782 | .PP |
1908 | .PP |
1783 | .Vb 1 |
1909 | .Vb 1 |
1784 | \& #include <ev++.h> |
1910 | \& #include <ev++.h> |
1785 | .Ve |
1911 | .Ve |
1786 | .PP |
1912 | .PP |
1787 | (it is not installed by default). This automatically includes \fIev.h\fR |
1913 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1788 | and puts all of its definitions (many of them macros) into the global |
1914 | of them macros) into the global namespace. All \*(C+ specific things are |
1789 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
1915 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
1916 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1790 | .PP |
1917 | .PP |
1791 | It should support all the same embedding options as \fIev.h\fR, most notably |
1918 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1792 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1919 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
1920 | that the watcher is associated with (or no additional members at all if |
|
|
1921 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
1922 | .PP |
|
|
1923 | Currently, functions, and static and non-static member functions can be |
|
|
1924 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1925 | need one additional pointer for context. If you need support for other |
|
|
1926 | types of functors please contact the author (preferably after implementing |
|
|
1927 | it). |
1793 | .PP |
1928 | .PP |
1794 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1929 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1795 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1930 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1796 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1931 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1797 | .IX Item "ev::READ, ev::WRITE etc." |
1932 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1809 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1944 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1810 | defines by many implementations. |
1945 | defines by many implementations. |
1811 | .Sp |
1946 | .Sp |
1812 | All of those classes have these methods: |
1947 | All of those classes have these methods: |
1813 | .RS 4 |
1948 | .RS 4 |
1814 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
1949 | .IP "ev::TYPE::TYPE ()" 4 |
1815 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
1950 | .IX Item "ev::TYPE::TYPE ()" |
1816 | .PD 0 |
1951 | .PD 0 |
1817 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
1952 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1818 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
1953 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1819 | .IP "ev::TYPE::~TYPE" 4 |
1954 | .IP "ev::TYPE::~TYPE" 4 |
1820 | .IX Item "ev::TYPE::~TYPE" |
1955 | .IX Item "ev::TYPE::~TYPE" |
1821 | .PD |
1956 | .PD |
1822 | The constructor takes a pointer to an object and a method pointer to |
1957 | The constructor (optionally) takes an event loop to associate the watcher |
1823 | the event handler callback to call in this class. The constructor calls |
1958 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1824 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
1959 | .Sp |
1825 | before starting it. If you do not specify a loop then the constructor |
1960 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1826 | automatically associates the default loop with this watcher. |
1961 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
1962 | .Sp |
|
|
1963 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
1964 | method to set a callback before you can start the watcher. |
|
|
1965 | .Sp |
|
|
1966 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
1967 | not allow explicit template arguments for constructors). |
1827 | .Sp |
1968 | .Sp |
1828 | The destructor automatically stops the watcher if it is active. |
1969 | The destructor automatically stops the watcher if it is active. |
|
|
1970 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
1971 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
1972 | This method sets the callback method to call. The method has to have a |
|
|
1973 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
1974 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
1975 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
1976 | .Sp |
|
|
1977 | This method synthesizes efficient thunking code to call your method from |
|
|
1978 | the C callback that libev requires. If your compiler can inline your |
|
|
1979 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
1980 | your compiler is good :), then the method will be fully inlined into the |
|
|
1981 | thunking function, making it as fast as a direct C callback. |
|
|
1982 | .Sp |
|
|
1983 | Example: simple class declaration and watcher initialisation |
|
|
1984 | .Sp |
|
|
1985 | .Vb 4 |
|
|
1986 | \& struct myclass |
|
|
1987 | \& { |
|
|
1988 | \& void io_cb (ev::io &w, int revents) { } |
|
|
1989 | \& } |
|
|
1990 | .Ve |
|
|
1991 | .Sp |
|
|
1992 | .Vb 3 |
|
|
1993 | \& myclass obj; |
|
|
1994 | \& ev::io iow; |
|
|
1995 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1996 | .Ve |
|
|
1997 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
1998 | .IX Item "w->set<function> (void *data = 0)" |
|
|
1999 | Also sets a callback, but uses a static method or plain function as |
|
|
2000 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2001 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2002 | .Sp |
|
|
2003 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2004 | .Sp |
|
|
2005 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2006 | .Sp |
|
|
2007 | Example: |
|
|
2008 | .Sp |
|
|
2009 | .Vb 2 |
|
|
2010 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2011 | \& iow.set <io_cb> (); |
|
|
2012 | .Ve |
1829 | .IP "w\->set (struct ev_loop *)" 4 |
2013 | .IP "w\->set (struct ev_loop *)" 4 |
1830 | .IX Item "w->set (struct ev_loop *)" |
2014 | .IX Item "w->set (struct ev_loop *)" |
1831 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2015 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1832 | do this when the watcher is inactive (and not pending either). |
2016 | do this when the watcher is inactive (and not pending either). |
1833 | .IP "w\->set ([args])" 4 |
2017 | .IP "w\->set ([args])" 4 |
1834 | .IX Item "w->set ([args])" |
2018 | .IX Item "w->set ([args])" |
1835 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2019 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1836 | called at least once. Unlike the C counterpart, an active watcher gets |
2020 | called at least once. Unlike the C counterpart, an active watcher gets |
1837 | automatically stopped and restarted. |
2021 | automatically stopped and restarted when reconfiguring it with this |
|
|
2022 | method. |
1838 | .IP "w\->start ()" 4 |
2023 | .IP "w\->start ()" 4 |
1839 | .IX Item "w->start ()" |
2024 | .IX Item "w->start ()" |
1840 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2025 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1841 | constructor already takes the loop. |
2026 | constructor already stores the event loop. |
1842 | .IP "w\->stop ()" 4 |
2027 | .IP "w\->stop ()" 4 |
1843 | .IX Item "w->stop ()" |
2028 | .IX Item "w->stop ()" |
1844 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2029 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1845 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2030 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1846 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2031 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1872 | .Vb 2 |
2057 | .Vb 2 |
1873 | \& myclass (); |
2058 | \& myclass (); |
1874 | \& } |
2059 | \& } |
1875 | .Ve |
2060 | .Ve |
1876 | .PP |
2061 | .PP |
1877 | .Vb 6 |
2062 | .Vb 4 |
1878 | \& myclass::myclass (int fd) |
2063 | \& myclass::myclass (int fd) |
1879 | \& : io (this, &myclass::io_cb), |
|
|
1880 | \& idle (this, &myclass::idle_cb) |
|
|
1881 | \& { |
2064 | \& { |
|
|
2065 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2066 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2067 | .Ve |
|
|
2068 | .PP |
|
|
2069 | .Vb 2 |
1882 | \& io.start (fd, ev::READ); |
2070 | \& io.start (fd, ev::READ); |
1883 | \& } |
2071 | \& } |
1884 | .Ve |
2072 | .Ve |
1885 | .SH "MACRO MAGIC" |
2073 | .SH "MACRO MAGIC" |
1886 | .IX Header "MACRO MAGIC" |
2074 | .IX Header "MACRO MAGIC" |
1887 | Libev can be compiled with a variety of options, the most fundemantal is |
2075 | Libev can be compiled with a variety of options, the most fundemantal is |
1888 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
2076 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
1889 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2077 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1890 | .PP |
2078 | .PP |
1891 | To make it easier to write programs that cope with either variant, the |
2079 | To make it easier to write programs that cope with either variant, the |
1892 | following macros are defined: |
2080 | following macros are defined: |
1893 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2081 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
… | |
… | |
1928 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
2116 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1929 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2117 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1930 | Similar to the other two macros, this gives you the value of the default |
2118 | Similar to the other two macros, this gives you the value of the default |
1931 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
2119 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
1932 | .PP |
2120 | .PP |
1933 | Example: Declare and initialise a check watcher, working regardless of |
2121 | Example: Declare and initialise a check watcher, utilising the above |
1934 | wether multiple loops are supported or not. |
2122 | macros so it will work regardless of whether multiple loops are supported |
|
|
2123 | or not. |
1935 | .PP |
2124 | .PP |
1936 | .Vb 5 |
2125 | .Vb 5 |
1937 | \& static void |
2126 | \& static void |
1938 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2127 | \& check_cb (EV_P_ ev_timer *w, int revents) |
1939 | \& { |
2128 | \& { |
… | |
… | |
2002 | .Vb 1 |
2191 | .Vb 1 |
2003 | \& ev_win32.c required on win32 platforms only |
2192 | \& ev_win32.c required on win32 platforms only |
2004 | .Ve |
2193 | .Ve |
2005 | .PP |
2194 | .PP |
2006 | .Vb 5 |
2195 | .Vb 5 |
2007 | \& ev_select.c only when select backend is enabled (which is by default) |
2196 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
2008 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2197 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2009 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2198 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2010 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2199 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2011 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2200 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2012 | .Ve |
2201 | .Ve |
… | |
… | |
2133 | otherwise another method will be used as fallback. This is the preferred |
2322 | otherwise another method will be used as fallback. This is the preferred |
2134 | backend for Solaris 10 systems. |
2323 | backend for Solaris 10 systems. |
2135 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2324 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2136 | .IX Item "EV_USE_DEVPOLL" |
2325 | .IX Item "EV_USE_DEVPOLL" |
2137 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2326 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2327 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2328 | .IX Item "EV_USE_INOTIFY" |
|
|
2329 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2330 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2331 | be detected at runtime. |
2138 | .IP "\s-1EV_H\s0" 4 |
2332 | .IP "\s-1EV_H\s0" 4 |
2139 | .IX Item "EV_H" |
2333 | .IX Item "EV_H" |
2140 | The name of the \fIev.h\fR header file used to include it. The default if |
2334 | The name of the \fIev.h\fR header file used to include it. The default if |
2141 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2335 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2142 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2336 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
2160 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2354 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2161 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2355 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2162 | additional independent event loops. Otherwise there will be no support |
2356 | additional independent event loops. Otherwise there will be no support |
2163 | for multiple event loops and there is no first event loop pointer |
2357 | for multiple event loops and there is no first event loop pointer |
2164 | argument. Instead, all functions act on the single default loop. |
2358 | argument. Instead, all functions act on the single default loop. |
|
|
2359 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2360 | .IX Item "EV_MINPRI" |
|
|
2361 | .PD 0 |
|
|
2362 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2363 | .IX Item "EV_MAXPRI" |
|
|
2364 | .PD |
|
|
2365 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2366 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2367 | provide for more priorities by overriding those symbols (usually defined |
|
|
2368 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2369 | .Sp |
|
|
2370 | When doing priority-based operations, libev usually has to linearly search |
|
|
2371 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2372 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2373 | fine. |
|
|
2374 | .Sp |
|
|
2375 | If your embedding app does not need any priorities, defining these both to |
|
|
2376 | \&\f(CW0\fR will save some memory and cpu. |
2165 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2377 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2166 | .IX Item "EV_PERIODIC_ENABLE" |
2378 | .IX Item "EV_PERIODIC_ENABLE" |
2167 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2379 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2380 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2381 | code. |
|
|
2382 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2383 | .IX Item "EV_IDLE_ENABLE" |
|
|
2384 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
2168 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2385 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2169 | code. |
2386 | code. |
2170 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2387 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2171 | .IX Item "EV_EMBED_ENABLE" |
2388 | .IX Item "EV_EMBED_ENABLE" |
2172 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2389 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
… | |
… | |
2187 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
2404 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
2188 | .IX Item "EV_PID_HASHSIZE" |
2405 | .IX Item "EV_PID_HASHSIZE" |
2189 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
2406 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
2190 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
2407 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
2191 | than enough. If you need to manage thousands of children you might want to |
2408 | than enough. If you need to manage thousands of children you might want to |
2192 | increase this value. |
2409 | increase this value (\fImust\fR be a power of two). |
|
|
2410 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2411 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2412 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2413 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2414 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2415 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2416 | two). |
2193 | .IP "\s-1EV_COMMON\s0" 4 |
2417 | .IP "\s-1EV_COMMON\s0" 4 |
2194 | .IX Item "EV_COMMON" |
2418 | .IX Item "EV_COMMON" |
2195 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2419 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2196 | this macro to a something else you can include more and other types of |
2420 | this macro to a something else you can include more and other types of |
2197 | members. You have to define it each time you include one of the files, |
2421 | members. You have to define it each time you include one of the files, |
… | |
… | |
2227 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2451 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2228 | will be compiled. It is pretty complex because it provides its own header |
2452 | will be compiled. It is pretty complex because it provides its own header |
2229 | file. |
2453 | file. |
2230 | .Sp |
2454 | .Sp |
2231 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2455 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2232 | that everybody includes and which overrides some autoconf choices: |
2456 | that everybody includes and which overrides some configure choices: |
2233 | .Sp |
2457 | .Sp |
2234 | .Vb 4 |
2458 | .Vb 9 |
|
|
2459 | \& #define EV_MINIMAL 1 |
2235 | \& #define EV_USE_POLL 0 |
2460 | \& #define EV_USE_POLL 0 |
2236 | \& #define EV_MULTIPLICITY 0 |
2461 | \& #define EV_MULTIPLICITY 0 |
2237 | \& #define EV_PERIODICS 0 |
2462 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2463 | \& #define EV_STAT_ENABLE 0 |
|
|
2464 | \& #define EV_FORK_ENABLE 0 |
2238 | \& #define EV_CONFIG_H <config.h> |
2465 | \& #define EV_CONFIG_H <config.h> |
|
|
2466 | \& #define EV_MINPRI 0 |
|
|
2467 | \& #define EV_MAXPRI 0 |
2239 | .Ve |
2468 | .Ve |
2240 | .Sp |
2469 | .Sp |
2241 | .Vb 1 |
2470 | .Vb 1 |
2242 | \& #include "ev++.h" |
2471 | \& #include "ev++.h" |
2243 | .Ve |
2472 | .Ve |
… | |
… | |
2251 | .SH "COMPLEXITIES" |
2480 | .SH "COMPLEXITIES" |
2252 | .IX Header "COMPLEXITIES" |
2481 | .IX Header "COMPLEXITIES" |
2253 | In this section the complexities of (many of) the algorithms used inside |
2482 | In this section the complexities of (many of) the algorithms used inside |
2254 | libev will be explained. For complexity discussions about backends see the |
2483 | libev will be explained. For complexity discussions about backends see the |
2255 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2484 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2485 | .Sp |
|
|
2486 | All of the following are about amortised time: If an array needs to be |
|
|
2487 | extended, libev needs to realloc and move the whole array, but this |
|
|
2488 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2489 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2490 | it is much faster and asymptotically approaches constant time. |
2256 | .RS 4 |
2491 | .RS 4 |
2257 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2492 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2258 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2493 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2259 | .PD 0 |
2494 | This means that, when you have a watcher that triggers in one hour and |
|
|
2495 | there are 100 watchers that would trigger before that then inserting will |
|
|
2496 | have to skip those 100 watchers. |
2260 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2497 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2261 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2498 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2499 | That means that for changing a timer costs less than removing/adding them |
|
|
2500 | as only the relative motion in the event queue has to be paid for. |
2262 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2501 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2263 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2502 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2264 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2503 | These just add the watcher into an array or at the head of a list. |
2265 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2504 | =item Stopping check/prepare/idle watchers: O(1) |
2266 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 |
2505 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2267 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" |
2506 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2507 | These watchers are stored in lists then need to be walked to find the |
|
|
2508 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2509 | have many watchers waiting for the same fd or signal). |
2268 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2510 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2269 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2511 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2512 | .PD 0 |
2270 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2513 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2271 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2514 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2515 | .PD |
|
|
2516 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2517 | libev to recalculate its status (and possibly tell the kernel). |
2272 | .IP "Activating one watcher: O(1)" 4 |
2518 | .IP "Activating one watcher: O(1)" 4 |
2273 | .IX Item "Activating one watcher: O(1)" |
2519 | .IX Item "Activating one watcher: O(1)" |
|
|
2520 | .PD 0 |
|
|
2521 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2522 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2523 | .PD |
|
|
2524 | Priorities are implemented by allocating some space for each |
|
|
2525 | priority. When doing priority-based operations, libev usually has to |
|
|
2526 | linearly search all the priorities. |
2274 | .RE |
2527 | .RE |
2275 | .RS 4 |
2528 | .RS 4 |
2276 | .PD |
|
|
2277 | .SH "AUTHOR" |
2529 | .SH "AUTHOR" |
2278 | .IX Header "AUTHOR" |
2530 | .IX Header "AUTHOR" |
2279 | Marc Lehmann <libev@schmorp.de>. |
2531 | Marc Lehmann <libev@schmorp.de>. |