… | |
… | |
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 "2007-11-29" "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 |
… | |
… | |
1069 | .IP "ev_timer_again (loop)" 4 |
1071 | .IP "ev_timer_again (loop)" 4 |
1070 | .IX Item "ev_timer_again (loop)" |
1072 | .IX Item "ev_timer_again (loop)" |
1071 | This will act as if the timer timed out and restart it again if it is |
1073 | This will act as if the timer timed out and restart it again if it is |
1072 | repeating. The exact semantics are: |
1074 | repeating. The exact semantics are: |
1073 | .Sp |
1075 | .Sp |
|
|
1076 | If the timer is pending, its pending status is cleared. |
|
|
1077 | .Sp |
1074 | If the timer is started but nonrepeating, stop it. |
1078 | If the timer is started but nonrepeating, stop it (as if it timed out). |
1075 | .Sp |
1079 | .Sp |
1076 | If the timer is repeating, either start it if necessary (with the repeat |
1080 | If the timer is repeating, either start it if necessary (with the |
1077 | value), or reset the running timer to the repeat value. |
1081 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1078 | .Sp |
1082 | .Sp |
1079 | This sounds a bit complicated, but here is a useful and typical |
1083 | 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 |
1084 | 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, |
1085 | 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 |
1086 | 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 |
1087 | 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 |
1088 | \&\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 |
1089 | 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 |
1090 | 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. |
1091 | automatically restart it if need be. |
1088 | .Sp |
1092 | .Sp |
1089 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1093 | 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: |
1094 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
1091 | .Sp |
1095 | .Sp |
1092 | .Vb 8 |
1096 | .Vb 8 |
1093 | \& ev_timer_init (timer, callback, 0., 5.); |
1097 | \& ev_timer_init (timer, callback, 0., 5.); |
1094 | \& ev_timer_again (loop, timer); |
1098 | \& ev_timer_again (loop, timer); |
1095 | \& ... |
1099 | \& ... |
… | |
… | |
1098 | \& ... |
1102 | \& ... |
1099 | \& timer->again = 10.; |
1103 | \& timer->again = 10.; |
1100 | \& ev_timer_again (loop, timer); |
1104 | \& ev_timer_again (loop, timer); |
1101 | .Ve |
1105 | .Ve |
1102 | .Sp |
1106 | .Sp |
1103 | This is more efficient then stopping/starting the timer eahc time you want |
1107 | This is more slightly efficient then stopping/starting the timer each time |
1104 | to modify its timeout value. |
1108 | you want to modify its timeout value. |
1105 | .IP "ev_tstamp repeat [read\-write]" 4 |
1109 | .IP "ev_tstamp repeat [read\-write]" 4 |
1106 | .IX Item "ev_tstamp repeat [read-write]" |
1110 | .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 |
1111 | 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), |
1112 | 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. |
1113 | 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 |
1386 | 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 |
1387 | 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 |
1388 | otherwise always forced to be at least one) and all the other fields of |
1385 | the stat buffer having unspecified contents. |
1389 | the stat buffer having unspecified contents. |
1386 | .PP |
1390 | .PP |
|
|
1391 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1392 | relative and your working directory changes, the behaviour is undefined. |
|
|
1393 | .PP |
1387 | Since there is no standard to do this, the portable implementation simply |
1394 | Since there is no standard to do this, the portable implementation simply |
1388 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
1395 | 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 |
1396 | 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, |
1397 | 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 |
1398 | unspecified default\fR value will be used (which you can expect to be around |
1392 | five seconds, although this might change dynamically). Libev will also |
1399 | five seconds, although this might change dynamically). Libev will also |
1393 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
1400 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
… | |
… | |
1395 | .PP |
1402 | .PP |
1396 | This watcher type is not meant for massive numbers of stat watchers, |
1403 | This watcher type is not meant for massive numbers of stat watchers, |
1397 | as even with OS-supported change notifications, this can be |
1404 | as even with OS-supported change notifications, this can be |
1398 | resource\-intensive. |
1405 | resource\-intensive. |
1399 | .PP |
1406 | .PP |
1400 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
1407 | At the time of this writing, only the Linux inotify interface is |
1401 | if demand increases, at least a kqueue and inotify backend will be added. |
1408 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1409 | reader). Inotify will be used to give hints only and should not change the |
|
|
1410 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1411 | to fall back to regular polling again even with inotify, but changes are |
|
|
1412 | usually detected immediately, and if the file exists there will be no |
|
|
1413 | polling. |
1402 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1414 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1403 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1415 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1404 | .PD 0 |
1416 | .PD 0 |
1405 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1417 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1406 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1418 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
2170 | otherwise another method will be used as fallback. This is the preferred |
2182 | otherwise another method will be used as fallback. This is the preferred |
2171 | backend for Solaris 10 systems. |
2183 | backend for Solaris 10 systems. |
2172 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2184 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2173 | .IX Item "EV_USE_DEVPOLL" |
2185 | .IX Item "EV_USE_DEVPOLL" |
2174 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2186 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2187 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2188 | .IX Item "EV_USE_INOTIFY" |
|
|
2189 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2190 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2191 | be detected at runtime. |
2175 | .IP "\s-1EV_H\s0" 4 |
2192 | .IP "\s-1EV_H\s0" 4 |
2176 | .IX Item "EV_H" |
2193 | .IX Item "EV_H" |
2177 | The name of the \fIev.h\fR header file used to include it. The default if |
2194 | The name of the \fIev.h\fR header file used to include it. The default if |
2178 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2195 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2179 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2196 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
2224 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
2241 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
2225 | .IX Item "EV_PID_HASHSIZE" |
2242 | .IX Item "EV_PID_HASHSIZE" |
2226 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
2243 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
2227 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
2244 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
2228 | than enough. If you need to manage thousands of children you might want to |
2245 | than enough. If you need to manage thousands of children you might want to |
2229 | increase this value. |
2246 | increase this value (\fImust\fR be a power of two). |
|
|
2247 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2248 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2249 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2250 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2251 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2252 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2253 | two). |
2230 | .IP "\s-1EV_COMMON\s0" 4 |
2254 | .IP "\s-1EV_COMMON\s0" 4 |
2231 | .IX Item "EV_COMMON" |
2255 | .IX Item "EV_COMMON" |
2232 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2256 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2233 | this macro to a something else you can include more and other types of |
2257 | this macro to a something else you can include more and other types of |
2234 | members. You have to define it each time you include one of the files, |
2258 | members. You have to define it each time you include one of the files, |
… | |
… | |
2298 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2322 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2299 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2323 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2300 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2324 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2301 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2325 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2302 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2326 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2303 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 |
2327 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2304 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" |
2328 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2305 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2329 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2306 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2330 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2307 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2331 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2308 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2332 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2309 | .IP "Activating one watcher: O(1)" 4 |
2333 | .IP "Activating one watcher: O(1)" 4 |