… | |
… | |
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 "2007-11-29" "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 |
… | |
… | |
409 | or setgid) then libev will \fInot\fR look at the environment variable |
411 | 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 |
412 | \&\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 |
413 | 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 |
414 | useful to try out specific backends to test their performance, or to work |
413 | around bugs. |
415 | around bugs. |
|
|
416 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
|
|
417 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
|
|
418 | .IX Item "EVFLAG_FORKCHECK" |
|
|
419 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
|
|
420 | a fork, you can also make libev check for a fork in each iteration by |
|
|
421 | enabling this flag. |
|
|
422 | .Sp |
|
|
423 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
|
|
424 | and thus this might slow down your event loop if you do a lot of loop |
|
|
425 | iterations and little real work, but is usually not noticable (on my |
|
|
426 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
|
|
427 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
|
|
428 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
|
|
429 | .Sp |
|
|
430 | The big advantage of this flag is that you can forget about fork (and |
|
|
431 | forget about forgetting to tell libev about forking) when you use this |
|
|
432 | flag. |
|
|
433 | .Sp |
|
|
434 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
|
|
435 | environment variable. |
414 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
436 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
415 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
437 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
416 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
438 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
417 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
439 | 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, |
440 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
1069 | .IP "ev_timer_again (loop)" 4 |
1091 | .IP "ev_timer_again (loop)" 4 |
1070 | .IX Item "ev_timer_again (loop)" |
1092 | .IX Item "ev_timer_again (loop)" |
1071 | This will act as if the timer timed out and restart it again if it is |
1093 | This will act as if the timer timed out and restart it again if it is |
1072 | repeating. The exact semantics are: |
1094 | repeating. The exact semantics are: |
1073 | .Sp |
1095 | .Sp |
|
|
1096 | If the timer is pending, its pending status is cleared. |
|
|
1097 | .Sp |
1074 | If the timer is started but nonrepeating, stop it. |
1098 | If the timer is started but nonrepeating, stop it (as if it timed out). |
1075 | .Sp |
1099 | .Sp |
1076 | If the timer is repeating, either start it if necessary (with the repeat |
1100 | If the timer is repeating, either start it if necessary (with the |
1077 | value), or reset the running timer to the repeat value. |
1101 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1078 | .Sp |
1102 | .Sp |
1079 | This sounds a bit complicated, but here is a useful and typical |
1103 | 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 |
1104 | 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, |
1105 | 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 |
1106 | 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 |
1107 | 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 |
1108 | \&\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 |
1109 | 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 |
1110 | 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. |
1111 | automatically restart it if need be. |
1088 | .Sp |
1112 | .Sp |
1089 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1113 | 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: |
1114 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
1091 | .Sp |
1115 | .Sp |
1092 | .Vb 8 |
1116 | .Vb 8 |
1093 | \& ev_timer_init (timer, callback, 0., 5.); |
1117 | \& ev_timer_init (timer, callback, 0., 5.); |
1094 | \& ev_timer_again (loop, timer); |
1118 | \& ev_timer_again (loop, timer); |
1095 | \& ... |
1119 | \& ... |
… | |
… | |
1098 | \& ... |
1122 | \& ... |
1099 | \& timer->again = 10.; |
1123 | \& timer->again = 10.; |
1100 | \& ev_timer_again (loop, timer); |
1124 | \& ev_timer_again (loop, timer); |
1101 | .Ve |
1125 | .Ve |
1102 | .Sp |
1126 | .Sp |
1103 | This is more efficient then stopping/starting the timer eahc time you want |
1127 | This is more slightly efficient then stopping/starting the timer each time |
1104 | to modify its timeout value. |
1128 | you want to modify its timeout value. |
1105 | .IP "ev_tstamp repeat [read\-write]" 4 |
1129 | .IP "ev_tstamp repeat [read\-write]" 4 |
1106 | .IX Item "ev_tstamp repeat [read-write]" |
1130 | .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 |
1131 | 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), |
1132 | 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. |
1133 | 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 |
1406 | 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 |
1407 | 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 |
1408 | otherwise always forced to be at least one) and all the other fields of |
1385 | the stat buffer having unspecified contents. |
1409 | the stat buffer having unspecified contents. |
1386 | .PP |
1410 | .PP |
|
|
1411 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1412 | relative and your working directory changes, the behaviour is undefined. |
|
|
1413 | .PP |
1387 | Since there is no standard to do this, the portable implementation simply |
1414 | 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 |
1415 | 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 |
1416 | 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, |
1417 | 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 |
1418 | unspecified default\fR value will be used (which you can expect to be around |
… | |
… | |
1970 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1997 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1971 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1998 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1972 | Similar to the other two macros, this gives you the value of the default |
1999 | 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"). |
2000 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
1974 | .PP |
2001 | .PP |
1975 | Example: Declare and initialise a check watcher, working regardless of |
2002 | Example: Declare and initialise a check watcher, utilising the above |
1976 | wether multiple loops are supported or not. |
2003 | macros so it will work regardless of wether multiple loops are supported |
|
|
2004 | or not. |
1977 | .PP |
2005 | .PP |
1978 | .Vb 5 |
2006 | .Vb 5 |
1979 | \& static void |
2007 | \& static void |
1980 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2008 | \& check_cb (EV_P_ ev_timer *w, int revents) |
1981 | \& { |
2009 | \& { |
… | |
… | |
2044 | .Vb 1 |
2072 | .Vb 1 |
2045 | \& ev_win32.c required on win32 platforms only |
2073 | \& ev_win32.c required on win32 platforms only |
2046 | .Ve |
2074 | .Ve |
2047 | .PP |
2075 | .PP |
2048 | .Vb 5 |
2076 | .Vb 5 |
2049 | \& ev_select.c only when select backend is enabled (which is by default) |
2077 | \& 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) |
2078 | \& 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) |
2079 | \& 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) |
2080 | \& 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) |
2081 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2054 | .Ve |
2082 | .Ve |
… | |
… | |
2281 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2309 | 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 |
2310 | will be compiled. It is pretty complex because it provides its own header |
2283 | file. |
2311 | file. |
2284 | .Sp |
2312 | .Sp |
2285 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2313 | 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: |
2314 | that everybody includes and which overrides some configure choices: |
2287 | .Sp |
2315 | .Sp |
2288 | .Vb 4 |
2316 | .Vb 9 |
|
|
2317 | \& #define EV_MINIMAL 1 |
2289 | \& #define EV_USE_POLL 0 |
2318 | \& #define EV_USE_POLL 0 |
2290 | \& #define EV_MULTIPLICITY 0 |
2319 | \& #define EV_MULTIPLICITY 0 |
2291 | \& #define EV_PERIODICS 0 |
2320 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2321 | \& #define EV_STAT_ENABLE 0 |
|
|
2322 | \& #define EV_FORK_ENABLE 0 |
2292 | \& #define EV_CONFIG_H <config.h> |
2323 | \& #define EV_CONFIG_H <config.h> |
|
|
2324 | \& #define EV_MINPRI 0 |
|
|
2325 | \& #define EV_MAXPRI 0 |
2293 | .Ve |
2326 | .Ve |
2294 | .Sp |
2327 | .Sp |
2295 | .Vb 1 |
2328 | .Vb 1 |
2296 | \& #include "ev++.h" |
2329 | \& #include "ev++.h" |
2297 | .Ve |
2330 | .Ve |