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132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "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" |
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137 | .Vb 1 |
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138 | \& #include <ev.h> |
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139 | .Ve |
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140 | .SH "EXAMPLE PROGRAM" |
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141 | .IX Header "EXAMPLE PROGRAM" |
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142 | .Vb 1 |
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143 | \& #include <ev.h> |
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144 | .Ve |
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145 | .PP |
137 | .Vb 2 |
146 | .Vb 2 |
138 | \& /* this is the only header you need */ |
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139 | \& #include <ev.h> |
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140 | .Ve |
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141 | .PP |
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142 | .Vb 3 |
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143 | \& /* what follows is a fully working example program */ |
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144 | \& ev_io stdin_watcher; |
147 | \& ev_io stdin_watcher; |
145 | \& ev_timer timeout_watcher; |
148 | \& ev_timer timeout_watcher; |
146 | .Ve |
149 | .Ve |
147 | .PP |
150 | .PP |
148 | .Vb 8 |
151 | .Vb 8 |
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207 | 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 |
208 | 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 |
209 | watcher. |
212 | watcher. |
210 | .SH "FEATURES" |
213 | .SH "FEATURES" |
211 | .IX Header "FEATURES" |
214 | .IX Header "FEATURES" |
212 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
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 |
213 | kqueue mechanisms for file descriptor events, relative timers, absolute |
216 | bsd-specific \f(CW\*(C`kqueue\*(C'\fR and the solaris-specific event port mechanisms |
214 | timers with customised rescheduling, signal events, process status change |
217 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), |
215 | events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event |
218 | absolute timers with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous |
216 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
219 | signals (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and |
217 | fast (see this benchmark comparing |
220 | event watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
218 | it to libevent for example). |
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 |
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222 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
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223 | (\f(CW\*(C`ev_fork\*(C'\fR). |
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224 | .PP |
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225 | It also is quite fast (see this |
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226 | benchmark comparing it to libevent |
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227 | for example). |
219 | .SH "CONVENTIONS" |
228 | .SH "CONVENTIONS" |
220 | .IX Header "CONVENTIONS" |
229 | .IX Header "CONVENTIONS" |
221 | Libev is very configurable. In this manual the default configuration |
230 | Libev is very configurable. In this manual the default configuration will |
222 | will be described, which supports multiple event loops. For more info |
231 | be described, which supports multiple event loops. For more info about |
223 | about various configuration options please have a look at the file |
232 | various configuration options please have a look at \fB\s-1EMBED\s0\fR section in |
224 | \&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without |
233 | this manual. If libev was configured without support for multiple event |
225 | support for multiple event loops, then all functions taking an initial |
234 | loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR |
226 | argument of name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) |
235 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
227 | will not have this argument. |
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228 | .SH "TIME REPRESENTATION" |
236 | .SH "TIME REPRESENTATION" |
229 | .IX Header "TIME REPRESENTATION" |
237 | .IX Header "TIME REPRESENTATION" |
230 | Libev represents time as a single floating point number, representing the |
238 | Libev represents time as a single floating point number, representing the |
231 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
239 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
232 | the beginning of 1970, details are complicated, don't ask). This type is |
240 | the beginning of 1970, details are complicated, don't ask). This type is |
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257 | Usually, it's a good idea to terminate if the major versions mismatch, |
265 | Usually, it's a good idea to terminate if the major versions mismatch, |
258 | as this indicates an incompatible change. Minor versions are usually |
266 | as this indicates an incompatible change. Minor versions are usually |
259 | compatible to older versions, so a larger minor version alone is usually |
267 | compatible to older versions, so a larger minor version alone is usually |
260 | not a problem. |
268 | not a problem. |
261 | .Sp |
269 | .Sp |
262 | Example: make sure we haven't accidentally been linked against the wrong |
270 | Example: Make sure we haven't accidentally been linked against the wrong |
263 | version: |
271 | version. |
264 | .Sp |
272 | .Sp |
265 | .Vb 3 |
273 | .Vb 3 |
266 | \& assert (("libev version mismatch", |
274 | \& assert (("libev version mismatch", |
267 | \& ev_version_major () == EV_VERSION_MAJOR |
275 | \& ev_version_major () == EV_VERSION_MAJOR |
268 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
276 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
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308 | .Sp |
316 | .Sp |
309 | You could override this function in high-availability programs to, say, |
317 | You could override this function in high-availability programs to, say, |
310 | free some memory if it cannot allocate memory, to use a special allocator, |
318 | free some memory if it cannot allocate memory, to use a special allocator, |
311 | or even to sleep a while and retry until some memory is available. |
319 | or even to sleep a while and retry until some memory is available. |
312 | .Sp |
320 | .Sp |
313 | Example: replace the libev allocator with one that waits a bit and then |
321 | Example: Replace the libev allocator with one that waits a bit and then |
314 | retries: better than mine). |
322 | retries). |
315 | .Sp |
323 | .Sp |
316 | .Vb 6 |
324 | .Vb 6 |
317 | \& static void * |
325 | \& static void * |
318 | \& persistent_realloc (void *ptr, size_t size) |
326 | \& persistent_realloc (void *ptr, size_t size) |
319 | \& { |
327 | \& { |
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345 | callback is set, then libev will expect it to remedy the sitution, no |
353 | callback is set, then libev will expect it to remedy the sitution, no |
346 | matter what, when it returns. That is, libev will generally retry the |
354 | matter what, when it returns. That is, libev will generally retry the |
347 | requested operation, or, if the condition doesn't go away, do bad stuff |
355 | requested operation, or, if the condition doesn't go away, do bad stuff |
348 | (such as abort). |
356 | (such as abort). |
349 | .Sp |
357 | .Sp |
350 | Example: do the same thing as libev does internally: |
358 | Example: This is basically the same thing that libev does internally, too. |
351 | .Sp |
359 | .Sp |
352 | .Vb 6 |
360 | .Vb 6 |
353 | \& static void |
361 | \& static void |
354 | \& fatal_error (const char *msg) |
362 | \& fatal_error (const char *msg) |
355 | \& { |
363 | \& { |
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504 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
512 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
505 | always distinct from the default loop. Unlike the default loop, it cannot |
513 | always distinct from the default loop. Unlike the default loop, it cannot |
506 | handle signal and child watchers, and attempts to do so will be greeted by |
514 | handle signal and child watchers, and attempts to do so will be greeted by |
507 | undefined behaviour (or a failed assertion if assertions are enabled). |
515 | undefined behaviour (or a failed assertion if assertions are enabled). |
508 | .Sp |
516 | .Sp |
509 | Example: try to create a event loop that uses epoll and nothing else. |
517 | Example: Try to create a event loop that uses epoll and nothing else. |
510 | .Sp |
518 | .Sp |
511 | .Vb 3 |
519 | .Vb 3 |
512 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
520 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
513 | \& if (!epoller) |
521 | \& if (!epoller) |
514 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
522 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
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612 | \& be handled here by queueing them when their watcher gets executed. |
620 | \& be handled here by queueing them when their watcher gets executed. |
613 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
621 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
614 | \& were used, return, otherwise continue with step *. |
622 | \& were used, return, otherwise continue with step *. |
615 | .Ve |
623 | .Ve |
616 | .Sp |
624 | .Sp |
617 | Example: queue some jobs and then loop until no events are outsanding |
625 | Example: Queue some jobs and then loop until no events are outsanding |
618 | anymore. |
626 | anymore. |
619 | .Sp |
627 | .Sp |
620 | .Vb 4 |
628 | .Vb 4 |
621 | \& ... queue jobs here, make sure they register event watchers as long |
629 | \& ... queue jobs here, make sure they register event watchers as long |
622 | \& ... as they still have work to do (even an idle watcher will do..) |
630 | \& ... as they still have work to do (even an idle watcher will do..) |
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644 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
652 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
645 | no event watchers registered by it are active. It is also an excellent |
653 | no event watchers registered by it are active. It is also an excellent |
646 | way to do this for generic recurring timers or from within third-party |
654 | way to do this for generic recurring timers or from within third-party |
647 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
655 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
648 | .Sp |
656 | .Sp |
649 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
657 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
650 | running when nothing else is active. |
658 | running when nothing else is active. |
651 | .Sp |
659 | .Sp |
652 | .Vb 4 |
660 | .Vb 4 |
653 | \& struct dv_signal exitsig; |
661 | \& struct ev_signal exitsig; |
654 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
662 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
655 | \& ev_signal_start (myloop, &exitsig); |
663 | \& ev_signal_start (loop, &exitsig); |
656 | \& evf_unref (myloop); |
664 | \& evf_unref (loop); |
657 | .Ve |
665 | .Ve |
658 | .Sp |
666 | .Sp |
659 | Example: for some weird reason, unregister the above signal handler again. |
667 | Example: For some weird reason, unregister the above signal handler again. |
660 | .Sp |
668 | .Sp |
661 | .Vb 2 |
669 | .Vb 2 |
662 | \& ev_ref (myloop); |
670 | \& ev_ref (loop); |
663 | \& ev_signal_stop (myloop, &exitsig); |
671 | \& ev_signal_stop (loop, &exitsig); |
664 | .Ve |
672 | .Ve |
665 | .SH "ANATOMY OF A WATCHER" |
673 | .SH "ANATOMY OF A WATCHER" |
666 | .IX Header "ANATOMY OF A WATCHER" |
674 | .IX Header "ANATOMY OF A WATCHER" |
667 | A watcher is a structure that you create and register to record your |
675 | A watcher is a structure that you create and register to record your |
668 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
676 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
… | |
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957 | The file descriptor being watched. |
965 | The file descriptor being watched. |
958 | .IP "int events [read\-only]" 4 |
966 | .IP "int events [read\-only]" 4 |
959 | .IX Item "int events [read-only]" |
967 | .IX Item "int events [read-only]" |
960 | The events being watched. |
968 | The events being watched. |
961 | .PP |
969 | .PP |
962 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
970 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
963 | readable, but only once. Since it is likely line\-buffered, you could |
971 | readable, but only once. Since it is likely line\-buffered, you could |
964 | attempt to read a whole line in the callback: |
972 | attempt to read a whole line in the callback. |
965 | .PP |
973 | .PP |
966 | .Vb 6 |
974 | .Vb 6 |
967 | \& static void |
975 | \& static void |
968 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
976 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
969 | \& { |
977 | \& { |
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1061 | .IX Item "ev_tstamp repeat [read-write]" |
1069 | .IX Item "ev_tstamp repeat [read-write]" |
1062 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1070 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1063 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1071 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1064 | which is also when any modifications are taken into account. |
1072 | which is also when any modifications are taken into account. |
1065 | .PP |
1073 | .PP |
1066 | Example: create a timer that fires after 60 seconds. |
1074 | Example: Create a timer that fires after 60 seconds. |
1067 | .PP |
1075 | .PP |
1068 | .Vb 5 |
1076 | .Vb 5 |
1069 | \& static void |
1077 | \& static void |
1070 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1078 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1071 | \& { |
1079 | \& { |
… | |
… | |
1077 | \& struct ev_timer mytimer; |
1085 | \& struct ev_timer mytimer; |
1078 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1086 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1079 | \& ev_timer_start (loop, &mytimer); |
1087 | \& ev_timer_start (loop, &mytimer); |
1080 | .Ve |
1088 | .Ve |
1081 | .PP |
1089 | .PP |
1082 | Example: create a timeout timer that times out after 10 seconds of |
1090 | Example: Create a timeout timer that times out after 10 seconds of |
1083 | inactivity. |
1091 | inactivity. |
1084 | .PP |
1092 | .PP |
1085 | .Vb 5 |
1093 | .Vb 5 |
1086 | \& static void |
1094 | \& static void |
1087 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1095 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
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1212 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1220 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1213 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1221 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1214 | switched off. Can be changed any time, but changes only take effect when |
1222 | switched off. Can be changed any time, but changes only take effect when |
1215 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1223 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1216 | .PP |
1224 | .PP |
1217 | Example: call a callback every hour, or, more precisely, whenever the |
1225 | Example: Call a callback every hour, or, more precisely, whenever the |
1218 | system clock is divisible by 3600. The callback invocation times have |
1226 | system clock is divisible by 3600. The callback invocation times have |
1219 | potentially a lot of jittering, but good long-term stability. |
1227 | potentially a lot of jittering, but good long-term stability. |
1220 | .PP |
1228 | .PP |
1221 | .Vb 5 |
1229 | .Vb 5 |
1222 | \& static void |
1230 | \& static void |
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1230 | \& struct ev_periodic hourly_tick; |
1238 | \& struct ev_periodic hourly_tick; |
1231 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1239 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1232 | \& ev_periodic_start (loop, &hourly_tick); |
1240 | \& ev_periodic_start (loop, &hourly_tick); |
1233 | .Ve |
1241 | .Ve |
1234 | .PP |
1242 | .PP |
1235 | Example: the same as above, but use a reschedule callback to do it: |
1243 | Example: The same as above, but use a reschedule callback to do it: |
1236 | .PP |
1244 | .PP |
1237 | .Vb 1 |
1245 | .Vb 1 |
1238 | \& #include <math.h> |
1246 | \& #include <math.h> |
1239 | .Ve |
1247 | .Ve |
1240 | .PP |
1248 | .PP |
… | |
… | |
1248 | .PP |
1256 | .PP |
1249 | .Vb 1 |
1257 | .Vb 1 |
1250 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1258 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1251 | .Ve |
1259 | .Ve |
1252 | .PP |
1260 | .PP |
1253 | Example: call a callback every hour, starting now: |
1261 | Example: Call a callback every hour, starting now: |
1254 | .PP |
1262 | .PP |
1255 | .Vb 4 |
1263 | .Vb 4 |
1256 | \& struct ev_periodic hourly_tick; |
1264 | \& struct ev_periodic hourly_tick; |
1257 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1265 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1258 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1266 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
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1309 | .IP "int rstatus [read\-write]" 4 |
1317 | .IP "int rstatus [read\-write]" 4 |
1310 | .IX Item "int rstatus [read-write]" |
1318 | .IX Item "int rstatus [read-write]" |
1311 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
1319 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
1312 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1320 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1313 | .PP |
1321 | .PP |
1314 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1322 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1315 | .PP |
1323 | .PP |
1316 | .Vb 5 |
1324 | .Vb 5 |
1317 | \& static void |
1325 | \& static void |
1318 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1326 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1319 | \& { |
1327 | \& { |
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1443 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1451 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1444 | Initialises and configures the idle watcher \- it has no parameters of any |
1452 | Initialises and configures the idle watcher \- it has no parameters of any |
1445 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1453 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1446 | believe me. |
1454 | believe me. |
1447 | .PP |
1455 | .PP |
1448 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1456 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1449 | callback, free it. Alos, use no error checking, as usual. |
1457 | callback, free it. Also, use no error checking, as usual. |
1450 | .PP |
1458 | .PP |
1451 | .Vb 7 |
1459 | .Vb 7 |
1452 | \& static void |
1460 | \& static void |
1453 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1461 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1454 | \& { |
1462 | \& { |