… | |
… | |
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 "2007-11-28" "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 |
… | |
… | |
210 | watchers\fR, which are relatively small C structures you initialise with the |
210 | 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 |
211 | details of the event, and then hand it over to libev by \fIstarting\fR the |
212 | watcher. |
212 | watcher. |
213 | .SH "FEATURES" |
213 | .SH "FEATURES" |
214 | .IX Header "FEATURES" |
214 | .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 |
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 |
216 | bsd-specific \f(CW\*(C`kqueue\*(C'\fR and the solaris-specific event port mechanisms |
216 | 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), |
217 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
|
|
218 | (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 |
219 | 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 |
220 | (\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, |
221 | 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 |
222 | \&\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 |
223 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
223 | (\f(CW\*(C`ev_fork\*(C'\fR). |
224 | (\f(CW\*(C`ev_fork\*(C'\fR). |
224 | .PP |
225 | .PP |
225 | It also is quite fast (see this |
226 | It also is quite fast (see this |
… | |
… | |
304 | might be supported on the current system, you would need to look at |
305 | 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 |
306 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
306 | recommended ones. |
307 | recommended ones. |
307 | .Sp |
308 | .Sp |
308 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
309 | 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 |
310 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
310 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" |
311 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
311 | Sets the allocation function to use (the prototype and semantics are |
312 | 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 |
313 | 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 |
314 | allocate and free memory (no surprises here). If it returns zero when |
314 | allocated, the library might abort or take some potentially destructive |
315 | memory needs to be allocated, the library might abort or take some |
315 | action. The default is your system realloc function. |
316 | potentially destructive action. The default is your system realloc |
|
|
317 | function. |
316 | .Sp |
318 | .Sp |
317 | You could override this function in high-availability programs to, say, |
319 | 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, |
320 | 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. |
321 | or even to sleep a while and retry until some memory is available. |
320 | .Sp |
322 | .Sp |
… | |
… | |
856 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
858 | 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 |
859 | 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 |
860 | 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 |
861 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
860 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
862 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
861 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
863 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
862 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
864 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
863 | Returns the callback currently set on the watcher. |
865 | Returns the callback currently set on the watcher. |
864 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
866 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
865 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
867 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
866 | Change the callback. You can change the callback at virtually any time |
868 | Change the callback. You can change the callback at virtually any time |
867 | (modulo threads). |
869 | (modulo threads). |
… | |
… | |
893 | \& struct my_io *w = (struct my_io *)w_; |
895 | \& struct my_io *w = (struct my_io *)w_; |
894 | \& ... |
896 | \& ... |
895 | \& } |
897 | \& } |
896 | .Ve |
898 | .Ve |
897 | .PP |
899 | .PP |
898 | More interesting and less C\-conformant ways of catsing your callback type |
900 | More interesting and less C\-conformant ways of casting your callback type |
899 | have been omitted.... |
901 | instead have been omitted. |
|
|
902 | .PP |
|
|
903 | Another common scenario is having some data structure with multiple |
|
|
904 | watchers: |
|
|
905 | .PP |
|
|
906 | .Vb 6 |
|
|
907 | \& struct my_biggy |
|
|
908 | \& { |
|
|
909 | \& int some_data; |
|
|
910 | \& ev_timer t1; |
|
|
911 | \& ev_timer t2; |
|
|
912 | \& } |
|
|
913 | .Ve |
|
|
914 | .PP |
|
|
915 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
916 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
917 | .PP |
|
|
918 | .Vb 1 |
|
|
919 | \& #include <stddef.h> |
|
|
920 | .Ve |
|
|
921 | .PP |
|
|
922 | .Vb 6 |
|
|
923 | \& static void |
|
|
924 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
925 | \& { |
|
|
926 | \& struct my_biggy big = (struct my_biggy * |
|
|
927 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
928 | \& } |
|
|
929 | .Ve |
|
|
930 | .PP |
|
|
931 | .Vb 6 |
|
|
932 | \& static void |
|
|
933 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
934 | \& { |
|
|
935 | \& struct my_biggy big = (struct my_biggy * |
|
|
936 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
937 | \& } |
|
|
938 | .Ve |
900 | .SH "WATCHER TYPES" |
939 | .SH "WATCHER TYPES" |
901 | .IX Header "WATCHER TYPES" |
940 | .IX Header "WATCHER TYPES" |
902 | This section describes each watcher in detail, but will not repeat |
941 | This section describes each watcher in detail, but will not repeat |
903 | information given in the last section. Any initialisation/set macros, |
942 | information given in the last section. Any initialisation/set macros, |
904 | functions and members specific to the watcher type are explained. |
943 | functions and members specific to the watcher type are explained. |
… | |
… | |
1345 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1384 | 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 |
1385 | 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 |
1386 | otherwise always forced to be at least one) and all the other fields of |
1348 | the stat buffer having unspecified contents. |
1387 | the stat buffer having unspecified contents. |
1349 | .PP |
1388 | .PP |
|
|
1389 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1390 | relative and your working directory changes, the behaviour is undefined. |
|
|
1391 | .PP |
1350 | Since there is no standard to do this, the portable implementation simply |
1392 | 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 |
1393 | 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 |
1394 | 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, |
1395 | 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 |
1396 | 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 |
1397 | 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 |
1398 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
… | |
… | |
1358 | .PP |
1400 | .PP |
1359 | This watcher type is not meant for massive numbers of stat watchers, |
1401 | This watcher type is not meant for massive numbers of stat watchers, |
1360 | as even with OS-supported change notifications, this can be |
1402 | as even with OS-supported change notifications, this can be |
1361 | resource\-intensive. |
1403 | resource\-intensive. |
1362 | .PP |
1404 | .PP |
1363 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
1405 | 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. |
1406 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1407 | reader). Inotify will be used to give hints only and should not change the |
|
|
1408 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1409 | to fall back to regular polling again even with inotify, but changes are |
|
|
1410 | usually detected immediately, and if the file exists there will be no |
|
|
1411 | polling. |
1365 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1412 | .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)" |
1413 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1367 | .PD 0 |
1414 | .PD 0 |
1368 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1415 | .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)" |
1416 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
2133 | otherwise another method will be used as fallback. This is the preferred |
2180 | otherwise another method will be used as fallback. This is the preferred |
2134 | backend for Solaris 10 systems. |
2181 | backend for Solaris 10 systems. |
2135 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2182 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2136 | .IX Item "EV_USE_DEVPOLL" |
2183 | .IX Item "EV_USE_DEVPOLL" |
2137 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2184 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2185 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2186 | .IX Item "EV_USE_INOTIFY" |
|
|
2187 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2188 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2189 | be detected at runtime. |
2138 | .IP "\s-1EV_H\s0" 4 |
2190 | .IP "\s-1EV_H\s0" 4 |
2139 | .IX Item "EV_H" |
2191 | .IX Item "EV_H" |
2140 | The name of the \fIev.h\fR header file used to include it. The default if |
2192 | 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 |
2193 | 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. |
2194 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
2187 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
2239 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
2188 | .IX Item "EV_PID_HASHSIZE" |
2240 | .IX Item "EV_PID_HASHSIZE" |
2189 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
2241 | \&\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 |
2242 | 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 |
2243 | than enough. If you need to manage thousands of children you might want to |
2192 | increase this value. |
2244 | increase this value (\fImust\fR be a power of two). |
|
|
2245 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2246 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2247 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2248 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2249 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2250 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2251 | two). |
2193 | .IP "\s-1EV_COMMON\s0" 4 |
2252 | .IP "\s-1EV_COMMON\s0" 4 |
2194 | .IX Item "EV_COMMON" |
2253 | .IX Item "EV_COMMON" |
2195 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2254 | 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 |
2255 | 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, |
2256 | members. You have to define it each time you include one of the files, |
… | |
… | |
2261 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2320 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2262 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2321 | .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)" |
2322 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2264 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2323 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2265 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2324 | .IX 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 |
2325 | .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))" |
2326 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2268 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2327 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2269 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2328 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2270 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2329 | .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)" |
2330 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2272 | .IP "Activating one watcher: O(1)" 4 |
2331 | .IP "Activating one watcher: O(1)" 4 |