… | |
… | |
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 "2007-12-07" "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 |
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202 | web page you might find easier to navigate when reading it for the first |
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203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
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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 |
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|
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 |
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|
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 |
… | |
… | |
863 | Returns the callback currently set on the watcher. |
898 | Returns the callback currently set on the watcher. |
864 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
899 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
865 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
900 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
866 | Change the callback. You can change the callback at virtually any time |
901 | Change the callback. You can change the callback at virtually any time |
867 | (modulo threads). |
902 | (modulo threads). |
|
|
903 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
904 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
905 | .PD 0 |
|
|
906 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
907 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
908 | .PD |
|
|
909 | Set and query the priority of the watcher. The priority is a small |
|
|
910 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
911 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
912 | before watchers with lower priority, but priority will not keep watchers |
|
|
913 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
914 | .Sp |
|
|
915 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
916 | invocation after new events have been received. This is useful, for |
|
|
917 | example, to reduce latency after idling, or more often, to bind two |
|
|
918 | watchers on the same event and make sure one is called first. |
|
|
919 | .Sp |
|
|
920 | If you need to suppress invocation when higher priority events are pending |
|
|
921 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
922 | .Sp |
|
|
923 | The default priority used by watchers when no priority has been set is |
|
|
924 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
925 | .Sp |
|
|
926 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
927 | fine, as long as you do not mind that the priority value you query might |
|
|
928 | or might not have been adjusted to be within valid range. |
868 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
929 | .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" |
930 | .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 |
931 | 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 |
932 | 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 |
933 | 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 |
1044 | 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. |
1045 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
985 | .PP |
1046 | .PP |
986 | If you cannot run the fd in non-blocking mode (for example you should not |
1047 | 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 |
1048 | 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 |
1049 | 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 |
1050 | such as poll (fortunately in our Xlib example, Xlib already does this on |
990 | its own, so its quite safe to use). |
1051 | its own, so its quite safe to use). |
991 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1052 | .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)" |
1053 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
993 | .PD 0 |
1054 | .PD 0 |
… | |
… | |
1069 | .IP "ev_timer_again (loop)" 4 |
1130 | .IP "ev_timer_again (loop)" 4 |
1070 | .IX Item "ev_timer_again (loop)" |
1131 | .IX Item "ev_timer_again (loop)" |
1071 | This will act as if the timer timed out and restart it again if it is |
1132 | This will act as if the timer timed out and restart it again if it is |
1072 | repeating. The exact semantics are: |
1133 | repeating. The exact semantics are: |
1073 | .Sp |
1134 | .Sp |
|
|
1135 | If the timer is pending, its pending status is cleared. |
|
|
1136 | .Sp |
1074 | If the timer is started but nonrepeating, stop it. |
1137 | If the timer is started but nonrepeating, stop it (as if it timed out). |
1075 | .Sp |
1138 | .Sp |
1076 | If the timer is repeating, either start it if necessary (with the repeat |
1139 | If the timer is repeating, either start it if necessary (with the |
1077 | value), or reset the running timer to the repeat value. |
1140 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1078 | .Sp |
1141 | .Sp |
1079 | This sounds a bit complicated, but here is a useful and typical |
1142 | 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 |
1143 | 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, |
1144 | 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 |
1145 | 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 |
1146 | 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 |
1147 | \&\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 |
1148 | 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 |
1149 | 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. |
1150 | automatically restart it if need be. |
1088 | .Sp |
1151 | .Sp |
1089 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1152 | 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: |
1153 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
1091 | .Sp |
1154 | .Sp |
1092 | .Vb 8 |
1155 | .Vb 8 |
1093 | \& ev_timer_init (timer, callback, 0., 5.); |
1156 | \& ev_timer_init (timer, callback, 0., 5.); |
1094 | \& ev_timer_again (loop, timer); |
1157 | \& ev_timer_again (loop, timer); |
1095 | \& ... |
1158 | \& ... |
… | |
… | |
1098 | \& ... |
1161 | \& ... |
1099 | \& timer->again = 10.; |
1162 | \& timer->again = 10.; |
1100 | \& ev_timer_again (loop, timer); |
1163 | \& ev_timer_again (loop, timer); |
1101 | .Ve |
1164 | .Ve |
1102 | .Sp |
1165 | .Sp |
1103 | This is more efficient then stopping/starting the timer eahc time you want |
1166 | This is more slightly efficient then stopping/starting the timer each time |
1104 | to modify its timeout value. |
1167 | you want to modify its timeout value. |
1105 | .IP "ev_tstamp repeat [read\-write]" 4 |
1168 | .IP "ev_tstamp repeat [read\-write]" 4 |
1106 | .IX Item "ev_tstamp repeat [read-write]" |
1169 | .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 |
1170 | 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), |
1171 | 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. |
1172 | which is also when any modifications are taken into account. |
… | |
… | |
1382 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1445 | 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 |
1446 | 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 |
1447 | otherwise always forced to be at least one) and all the other fields of |
1385 | the stat buffer having unspecified contents. |
1448 | the stat buffer having unspecified contents. |
1386 | .PP |
1449 | .PP |
|
|
1450 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1451 | relative and your working directory changes, the behaviour is undefined. |
|
|
1452 | .PP |
1387 | Since there is no standard to do this, the portable implementation simply |
1453 | 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 |
1454 | 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 |
1455 | 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, |
1456 | 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 |
1457 | unspecified default\fR value will be used (which you can expect to be around |
… | |
… | |
1472 | \& ev_stat_start (loop, &passwd); |
1538 | \& ev_stat_start (loop, &passwd); |
1473 | .Ve |
1539 | .Ve |
1474 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1540 | .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..." |
1541 | .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..." |
1542 | .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 |
1543 | 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 |
1544 | priority are pending (prepare, check and other idle watchers do not |
1479 | as your process is busy handling sockets or timeouts (or even signals, |
1545 | count). |
1480 | imagine) it will not be triggered. But when your process is idle all idle |
1546 | .PP |
1481 | watchers are being called again and again, once per event loop iteration \- |
1547 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1548 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1549 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1550 | 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 |
1551 | iteration \- until stopped, that is, or your process receives more events |
1483 | busy. |
1552 | and becomes busy again with higher priority stuff. |
1484 | .PP |
1553 | .PP |
1485 | The most noteworthy effect is that as long as any idle watchers are |
1554 | 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. |
1555 | active, the process will not block when waiting for new events. |
1487 | .PP |
1556 | .PP |
1488 | Apart from keeping your process non-blocking (which is a useful |
1557 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1583 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1652 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1584 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1653 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1585 | \& } |
1654 | \& } |
1586 | .Ve |
1655 | .Ve |
1587 | .PP |
1656 | .PP |
1588 | .Vb 7 |
1657 | .Vb 8 |
1589 | \& // create io watchers for each fd and a timer before blocking |
1658 | \& // create io watchers for each fd and a timer before blocking |
1590 | \& static void |
1659 | \& static void |
1591 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1660 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1592 | \& { |
1661 | \& { |
1593 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1662 | \& int timeout = 3600000; |
|
|
1663 | \& struct pollfd fds [nfd]; |
1594 | \& // actual code will need to loop here and realloc etc. |
1664 | \& // actual code will need to loop here and realloc etc. |
1595 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1665 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1596 | .Ve |
1666 | .Ve |
1597 | .PP |
1667 | .PP |
1598 | .Vb 3 |
1668 | .Vb 3 |
… | |
… | |
1824 | .PP |
1894 | .PP |
1825 | .Vb 1 |
1895 | .Vb 1 |
1826 | \& #include <ev++.h> |
1896 | \& #include <ev++.h> |
1827 | .Ve |
1897 | .Ve |
1828 | .PP |
1898 | .PP |
1829 | (it is not installed by default). This automatically includes \fIev.h\fR |
1899 | 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 |
1900 | 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. |
1901 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
1902 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1832 | .PP |
1903 | .PP |
1833 | It should support all the same embedding options as \fIev.h\fR, most notably |
1904 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1834 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1905 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
1906 | that the watcher is associated with (or no additional members at all if |
|
|
1907 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
1908 | .PP |
|
|
1909 | Currently, functions, and static and non-static member functions can be |
|
|
1910 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1911 | need one additional pointer for context. If you need support for other |
|
|
1912 | types of functors please contact the author (preferably after implementing |
|
|
1913 | it). |
1835 | .PP |
1914 | .PP |
1836 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1915 | 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 |
1916 | .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 |
1917 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1839 | .IX Item "ev::READ, ev::WRITE etc." |
1918 | .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 |
1930 | 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. |
1931 | defines by many implementations. |
1853 | .Sp |
1932 | .Sp |
1854 | All of those classes have these methods: |
1933 | All of those classes have these methods: |
1855 | .RS 4 |
1934 | .RS 4 |
1856 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
1935 | .IP "ev::TYPE::TYPE ()" 4 |
1857 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
1936 | .IX Item "ev::TYPE::TYPE ()" |
1858 | .PD 0 |
1937 | .PD 0 |
1859 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
1938 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1860 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
1939 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1861 | .IP "ev::TYPE::~TYPE" 4 |
1940 | .IP "ev::TYPE::~TYPE" 4 |
1862 | .IX Item "ev::TYPE::~TYPE" |
1941 | .IX Item "ev::TYPE::~TYPE" |
1863 | .PD |
1942 | .PD |
1864 | The constructor takes a pointer to an object and a method pointer to |
1943 | The constructor (optionally) takes an event loop to associate the watcher |
1865 | the event handler callback to call in this class. The constructor calls |
1944 | 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 |
1945 | .Sp |
1867 | before starting it. If you do not specify a loop then the constructor |
1946 | 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. |
1947 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
1948 | .Sp |
|
|
1949 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
1950 | method to set a callback before you can start the watcher. |
|
|
1951 | .Sp |
|
|
1952 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
1953 | not allow explicit template arguments for constructors). |
1869 | .Sp |
1954 | .Sp |
1870 | The destructor automatically stops the watcher if it is active. |
1955 | The destructor automatically stops the watcher if it is active. |
|
|
1956 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
1957 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
1958 | This method sets the callback method to call. The method has to have a |
|
|
1959 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
1960 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
1961 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
1962 | .Sp |
|
|
1963 | This method synthesizes efficient thunking code to call your method from |
|
|
1964 | the C callback that libev requires. If your compiler can inline your |
|
|
1965 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
1966 | your compiler is good :), then the method will be fully inlined into the |
|
|
1967 | thunking function, making it as fast as a direct C callback. |
|
|
1968 | .Sp |
|
|
1969 | Example: simple class declaration and watcher initialisation |
|
|
1970 | .Sp |
|
|
1971 | .Vb 4 |
|
|
1972 | \& struct myclass |
|
|
1973 | \& { |
|
|
1974 | \& void io_cb (ev::io &w, int revents) { } |
|
|
1975 | \& } |
|
|
1976 | .Ve |
|
|
1977 | .Sp |
|
|
1978 | .Vb 3 |
|
|
1979 | \& myclass obj; |
|
|
1980 | \& ev::io iow; |
|
|
1981 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1982 | .Ve |
|
|
1983 | .IP "w\->set (void (*function)(watcher &w, int), void *data = 0)" 4 |
|
|
1984 | .IX Item "w->set (void (*function)(watcher &w, int), void *data = 0)" |
|
|
1985 | Also sets a callback, but uses a static method or plain function as |
|
|
1986 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
1987 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
1988 | .Sp |
|
|
1989 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
1871 | .IP "w\->set (struct ev_loop *)" 4 |
1990 | .IP "w\->set (struct ev_loop *)" 4 |
1872 | .IX Item "w->set (struct ev_loop *)" |
1991 | .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 |
1992 | 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). |
1993 | do this when the watcher is inactive (and not pending either). |
1875 | .IP "w\->set ([args])" 4 |
1994 | .IP "w\->set ([args])" 4 |
1876 | .IX Item "w->set ([args])" |
1995 | .IX Item "w->set ([args])" |
1877 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1996 | 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 |
1997 | called at least once. Unlike the C counterpart, an active watcher gets |
1879 | automatically stopped and restarted. |
1998 | automatically stopped and restarted when reconfiguring it with this |
|
|
1999 | method. |
1880 | .IP "w\->start ()" 4 |
2000 | .IP "w\->start ()" 4 |
1881 | .IX Item "w->start ()" |
2001 | .IX Item "w->start ()" |
1882 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2002 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1883 | constructor already takes the loop. |
2003 | constructor already stores the event loop. |
1884 | .IP "w\->stop ()" 4 |
2004 | .IP "w\->stop ()" 4 |
1885 | .IX Item "w->stop ()" |
2005 | .IX Item "w->stop ()" |
1886 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2006 | 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 |
2007 | .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 |
2008 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1914 | .Vb 2 |
2034 | .Vb 2 |
1915 | \& myclass (); |
2035 | \& myclass (); |
1916 | \& } |
2036 | \& } |
1917 | .Ve |
2037 | .Ve |
1918 | .PP |
2038 | .PP |
1919 | .Vb 6 |
2039 | .Vb 4 |
1920 | \& myclass::myclass (int fd) |
2040 | \& myclass::myclass (int fd) |
1921 | \& : io (this, &myclass::io_cb), |
|
|
1922 | \& idle (this, &myclass::idle_cb) |
|
|
1923 | \& { |
2041 | \& { |
|
|
2042 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2043 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2044 | .Ve |
|
|
2045 | .PP |
|
|
2046 | .Vb 2 |
1924 | \& io.start (fd, ev::READ); |
2047 | \& io.start (fd, ev::READ); |
1925 | \& } |
2048 | \& } |
1926 | .Ve |
2049 | .Ve |
1927 | .SH "MACRO MAGIC" |
2050 | .SH "MACRO MAGIC" |
1928 | .IX Header "MACRO MAGIC" |
2051 | .IX Header "MACRO MAGIC" |
1929 | Libev can be compiled with a variety of options, the most fundemantal is |
2052 | 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 |
2053 | \&\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. |
2054 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1932 | .PP |
2055 | .PP |
1933 | To make it easier to write programs that cope with either variant, the |
2056 | To make it easier to write programs that cope with either variant, the |
1934 | following macros are defined: |
2057 | following macros are defined: |
1935 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2058 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
… | |
… | |
1970 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
2093 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1971 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2094 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1972 | Similar to the other two macros, this gives you the value of the default |
2095 | 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"). |
2096 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
1974 | .PP |
2097 | .PP |
1975 | Example: Declare and initialise a check watcher, working regardless of |
2098 | Example: Declare and initialise a check watcher, utilising the above |
1976 | wether multiple loops are supported or not. |
2099 | macros so it will work regardless of whether multiple loops are supported |
|
|
2100 | or not. |
1977 | .PP |
2101 | .PP |
1978 | .Vb 5 |
2102 | .Vb 5 |
1979 | \& static void |
2103 | \& static void |
1980 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2104 | \& check_cb (EV_P_ ev_timer *w, int revents) |
1981 | \& { |
2105 | \& { |
… | |
… | |
2044 | .Vb 1 |
2168 | .Vb 1 |
2045 | \& ev_win32.c required on win32 platforms only |
2169 | \& ev_win32.c required on win32 platforms only |
2046 | .Ve |
2170 | .Ve |
2047 | .PP |
2171 | .PP |
2048 | .Vb 5 |
2172 | .Vb 5 |
2049 | \& ev_select.c only when select backend is enabled (which is by default) |
2173 | \& 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) |
2174 | \& 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) |
2175 | \& 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) |
2176 | \& 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) |
2177 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2054 | .Ve |
2178 | .Ve |
… | |
… | |
2207 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2331 | 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 |
2332 | 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 |
2333 | additional independent event loops. Otherwise there will be no support |
2210 | for multiple event loops and there is no first event loop pointer |
2334 | for multiple event loops and there is no first event loop pointer |
2211 | argument. Instead, all functions act on the single default loop. |
2335 | argument. Instead, all functions act on the single default loop. |
|
|
2336 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2337 | .IX Item "EV_MINPRI" |
|
|
2338 | .PD 0 |
|
|
2339 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2340 | .IX Item "EV_MAXPRI" |
|
|
2341 | .PD |
|
|
2342 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2343 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2344 | provide for more priorities by overriding those symbols (usually defined |
|
|
2345 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2346 | .Sp |
|
|
2347 | When doing priority-based operations, libev usually has to linearly search |
|
|
2348 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2349 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2350 | fine. |
|
|
2351 | .Sp |
|
|
2352 | If your embedding app does not need any priorities, defining these both to |
|
|
2353 | \&\f(CW0\fR will save some memory and cpu. |
2212 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2354 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2213 | .IX Item "EV_PERIODIC_ENABLE" |
2355 | .IX Item "EV_PERIODIC_ENABLE" |
2214 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2356 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2357 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2358 | code. |
|
|
2359 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2360 | .IX Item "EV_IDLE_ENABLE" |
|
|
2361 | 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 |
2362 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2216 | code. |
2363 | code. |
2217 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2364 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2218 | .IX Item "EV_EMBED_ENABLE" |
2365 | .IX Item "EV_EMBED_ENABLE" |
2219 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2366 | 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 |
2428 | 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 |
2429 | will be compiled. It is pretty complex because it provides its own header |
2283 | file. |
2430 | file. |
2284 | .Sp |
2431 | .Sp |
2285 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2432 | 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: |
2433 | that everybody includes and which overrides some configure choices: |
2287 | .Sp |
2434 | .Sp |
2288 | .Vb 4 |
2435 | .Vb 9 |
|
|
2436 | \& #define EV_MINIMAL 1 |
2289 | \& #define EV_USE_POLL 0 |
2437 | \& #define EV_USE_POLL 0 |
2290 | \& #define EV_MULTIPLICITY 0 |
2438 | \& #define EV_MULTIPLICITY 0 |
2291 | \& #define EV_PERIODICS 0 |
2439 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2440 | \& #define EV_STAT_ENABLE 0 |
|
|
2441 | \& #define EV_FORK_ENABLE 0 |
2292 | \& #define EV_CONFIG_H <config.h> |
2442 | \& #define EV_CONFIG_H <config.h> |
|
|
2443 | \& #define EV_MINPRI 0 |
|
|
2444 | \& #define EV_MAXPRI 0 |
2293 | .Ve |
2445 | .Ve |
2294 | .Sp |
2446 | .Sp |
2295 | .Vb 1 |
2447 | .Vb 1 |
2296 | \& #include "ev++.h" |
2448 | \& #include "ev++.h" |
2297 | .Ve |
2449 | .Ve |
… | |
… | |
2305 | .SH "COMPLEXITIES" |
2457 | .SH "COMPLEXITIES" |
2306 | .IX Header "COMPLEXITIES" |
2458 | .IX Header "COMPLEXITIES" |
2307 | In this section the complexities of (many of) the algorithms used inside |
2459 | In this section the complexities of (many of) the algorithms used inside |
2308 | libev will be explained. For complexity discussions about backends see the |
2460 | libev will be explained. For complexity discussions about backends see the |
2309 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2461 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
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2462 | .Sp |
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2463 | All of the following are about amortised time: If an array needs to be |
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2464 | extended, libev needs to realloc and move the whole array, but this |
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2465 | happens asymptotically never with higher number of elements, so O(1) might |
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2466 | mean it might do a lengthy realloc operation in rare cases, but on average |
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2467 | it is much faster and asymptotically approaches constant time. |
2310 | .RS 4 |
2468 | .RS 4 |
2311 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2469 | .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)" |
2470 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2313 | .PD 0 |
2471 | This means that, when you have a watcher that triggers in one hour and |
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2472 | there are 100 watchers that would trigger before that then inserting will |
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2473 | have to skip those 100 watchers. |
2314 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2474 | .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)" |
2475 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
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2476 | That means that for changing a timer costs less than removing/adding them |
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2477 | 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 |
2478 | .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)" |
2479 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2318 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2480 | 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)" |
2481 | =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 |
2482 | .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))" |
2483 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
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2484 | These watchers are stored in lists then need to be walked to find the |
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2485 | correct watcher to remove. The lists are usually short (you don't usually |
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2486 | have many watchers waiting for the same fd or signal). |
2322 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2487 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2323 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2488 | .IX Item "Finding the next timer per loop iteration: O(1)" |
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2489 | .PD 0 |
2324 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2490 | .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)" |
2491 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
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2492 | .PD |
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2493 | A change means an I/O watcher gets started or stopped, which requires |
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2494 | libev to recalculate its status (and possibly tell the kernel). |
2326 | .IP "Activating one watcher: O(1)" 4 |
2495 | .IP "Activating one watcher: O(1)" 4 |
2327 | .IX Item "Activating one watcher: O(1)" |
2496 | .IX Item "Activating one watcher: O(1)" |
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2497 | .PD 0 |
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2498 | .IP "Priority handling: O(number_of_priorities)" 4 |
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2499 | .IX Item "Priority handling: O(number_of_priorities)" |
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2500 | .PD |
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2501 | Priorities are implemented by allocating some space for each |
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2502 | priority. When doing priority-based operations, libev usually has to |
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2503 | linearly search all the priorities. |
2328 | .RE |
2504 | .RE |
2329 | .RS 4 |
2505 | .RS 4 |
2330 | .PD |
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2331 | .SH "AUTHOR" |
2506 | .SH "AUTHOR" |
2332 | .IX Header "AUTHOR" |
2507 | .IX Header "AUTHOR" |
2333 | Marc Lehmann <libev@schmorp.de>. |
2508 | Marc Lehmann <libev@schmorp.de>. |