… | |
… | |
126 | . ds Ae AE |
126 | . ds Ae AE |
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 "EV 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-08" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH EV 1 "2007-12-19" "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 |
… | |
… | |
243 | Libev represents time as a single floating point number, representing the |
243 | Libev represents time as a single floating point number, representing the |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
246 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
246 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
247 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
247 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
248 | it, you should treat it as such. |
248 | it, you should treat it as some floatingpoint value. Unlike the name |
|
|
249 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
|
|
250 | throughout libev. |
249 | .SH "GLOBAL FUNCTIONS" |
251 | .SH "GLOBAL FUNCTIONS" |
250 | .IX Header "GLOBAL FUNCTIONS" |
252 | .IX Header "GLOBAL FUNCTIONS" |
251 | These functions can be called anytime, even before initialising the |
253 | These functions can be called anytime, even before initialising the |
252 | library in any way. |
254 | library in any way. |
253 | .IP "ev_tstamp ev_time ()" 4 |
255 | .IP "ev_tstamp ev_time ()" 4 |
… | |
… | |
259 | .IX Item "int ev_version_major ()" |
261 | .IX Item "int ev_version_major ()" |
260 | .PD 0 |
262 | .PD 0 |
261 | .IP "int ev_version_minor ()" 4 |
263 | .IP "int ev_version_minor ()" 4 |
262 | .IX Item "int ev_version_minor ()" |
264 | .IX Item "int ev_version_minor ()" |
263 | .PD |
265 | .PD |
264 | You can find out the major and minor version numbers of the library |
266 | You can find out the major and minor \s-1ABI\s0 version numbers of the library |
265 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
267 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
266 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
268 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
267 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
269 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
268 | version of the library your program was compiled against. |
270 | version of the library your program was compiled against. |
269 | .Sp |
271 | .Sp |
|
|
272 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
|
|
273 | release version. |
|
|
274 | .Sp |
270 | Usually, it's a good idea to terminate if the major versions mismatch, |
275 | Usually, it's a good idea to terminate if the major versions mismatch, |
271 | as this indicates an incompatible change. Minor versions are usually |
276 | as this indicates an incompatible change. Minor versions are usually |
272 | compatible to older versions, so a larger minor version alone is usually |
277 | compatible to older versions, so a larger minor version alone is usually |
273 | not a problem. |
278 | not a problem. |
274 | .Sp |
279 | .Sp |
275 | Example: Make sure we haven't accidentally been linked against the wrong |
280 | Example: Make sure we haven't accidentally been linked against the wrong |
276 | version. |
281 | version. |
… | |
… | |
552 | Destroys the default loop again (frees all memory and kernel state |
557 | Destroys the default loop again (frees all memory and kernel state |
553 | etc.). None of the active event watchers will be stopped in the normal |
558 | etc.). None of the active event watchers will be stopped in the normal |
554 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
559 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
555 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
560 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
556 | calling this function, or cope with the fact afterwards (which is usually |
561 | calling this function, or cope with the fact afterwards (which is usually |
557 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
562 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
558 | for example). |
563 | for example). |
|
|
564 | .Sp |
|
|
565 | Not that certain global state, such as signal state, will not be freed by |
|
|
566 | this function, and related watchers (such as signal and child watchers) |
|
|
567 | would need to be stopped manually. |
|
|
568 | .Sp |
|
|
569 | In general it is not advisable to call this function except in the |
|
|
570 | rare occasion where you really need to free e.g. the signal handling |
|
|
571 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
572 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). |
559 | .IP "ev_loop_destroy (loop)" 4 |
573 | .IP "ev_loop_destroy (loop)" 4 |
560 | .IX Item "ev_loop_destroy (loop)" |
574 | .IX Item "ev_loop_destroy (loop)" |
561 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
575 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
562 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
576 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
563 | .IP "ev_default_fork ()" 4 |
577 | .IP "ev_default_fork ()" 4 |
… | |
… | |
634 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
648 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
635 | usually a better approach for this kind of thing. |
649 | usually a better approach for this kind of thing. |
636 | .Sp |
650 | .Sp |
637 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
651 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
638 | .Sp |
652 | .Sp |
639 | .Vb 18 |
653 | .Vb 19 |
|
|
654 | \& - Before the first iteration, call any pending watchers. |
640 | \& * If there are no active watchers (reference count is zero), return. |
655 | \& * If there are no active watchers (reference count is zero), return. |
641 | \& - Queue prepare watchers and then call all outstanding watchers. |
656 | \& - Queue all prepare watchers and then call all outstanding watchers. |
642 | \& - If we have been forked, recreate the kernel state. |
657 | \& - If we have been forked, recreate the kernel state. |
643 | \& - Update the kernel state with all outstanding changes. |
658 | \& - Update the kernel state with all outstanding changes. |
644 | \& - Update the "event loop time". |
659 | \& - Update the "event loop time". |
645 | \& - Calculate for how long to block. |
660 | \& - Calculate for how long to block. |
646 | \& - Block the process, waiting for any events. |
661 | \& - Block the process, waiting for any events. |
… | |
… | |
1061 | If you cannot run the fd in non-blocking mode (for example you should not |
1076 | If you cannot run the fd in non-blocking mode (for example you should not |
1062 | play around with an Xlib connection), then you have to seperately re-test |
1077 | play around with an Xlib connection), then you have to seperately re-test |
1063 | whether a file descriptor is really ready with a known-to-be good interface |
1078 | whether a file descriptor is really ready with a known-to-be good interface |
1064 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1079 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1065 | its own, so its quite safe to use). |
1080 | its own, so its quite safe to use). |
|
|
1081 | .PP |
|
|
1082 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1083 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1084 | .PP |
|
|
1085 | Some backends (e.g kqueue, epoll) need to be told about closing a file |
|
|
1086 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1087 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1088 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1089 | this interest. If another file descriptor with the same number then is |
|
|
1090 | registered with libev, there is no efficient way to see that this is, in |
|
|
1091 | fact, a different file descriptor. |
|
|
1092 | .PP |
|
|
1093 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1094 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1095 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1096 | it is assumed that the file descriptor stays the same. That means that |
|
|
1097 | you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the |
|
|
1098 | descriptor even if the file descriptor number itself did not change. |
|
|
1099 | .PP |
|
|
1100 | This is how one would do it normally anyway, the important point is that |
|
|
1101 | the libev application should not optimise around libev but should leave |
|
|
1102 | optimisations to libev. |
|
|
1103 | .PP |
|
|
1104 | \fIWatcher-Specific Functions\fR |
|
|
1105 | .IX Subsection "Watcher-Specific Functions" |
1066 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1106 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1067 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1107 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1068 | .PD 0 |
1108 | .PD 0 |
1069 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1109 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1070 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1110 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
… | |
… | |
1123 | .Ve |
1163 | .Ve |
1124 | .PP |
1164 | .PP |
1125 | The callback is guarenteed to be invoked only when its timeout has passed, |
1165 | The callback is guarenteed to be invoked only when its timeout has passed, |
1126 | but if multiple timers become ready during the same loop iteration then |
1166 | but if multiple timers become ready during the same loop iteration then |
1127 | order of execution is undefined. |
1167 | order of execution is undefined. |
|
|
1168 | .PP |
|
|
1169 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1170 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1128 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1171 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1129 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1172 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1130 | .PD 0 |
1173 | .PD 0 |
1131 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1174 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1132 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1175 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
1234 | but on wallclock time (absolute time). You can tell a periodic watcher |
1277 | but on wallclock time (absolute time). You can tell a periodic watcher |
1235 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1278 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1236 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1279 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1237 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1280 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1238 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1281 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1239 | roughly 10 seconds later and of course not if you reset your system time |
1282 | roughly 10 seconds later). |
1240 | again). |
|
|
1241 | .PP |
1283 | .PP |
1242 | They can also be used to implement vastly more complex timers, such as |
1284 | They can also be used to implement vastly more complex timers, such as |
1243 | triggering an event on eahc midnight, local time. |
1285 | triggering an event on each midnight, local time or other, complicated, |
|
|
1286 | rules. |
1244 | .PP |
1287 | .PP |
1245 | As with timers, the callback is guarenteed to be invoked only when the |
1288 | As with timers, the callback is guarenteed to be invoked only when the |
1246 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1289 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1247 | during the same loop iteration then order of execution is undefined. |
1290 | during the same loop iteration then order of execution is undefined. |
|
|
1291 | .PP |
|
|
1292 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1293 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1248 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1294 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1249 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1295 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1250 | .PD 0 |
1296 | .PD 0 |
1251 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1297 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1252 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1298 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1253 | .PD |
1299 | .PD |
1254 | Lots of arguments, lets sort it out... There are basically three modes of |
1300 | Lots of arguments, lets sort it out... There are basically three modes of |
1255 | operation, and we will explain them from simplest to complex: |
1301 | operation, and we will explain them from simplest to complex: |
1256 | .RS 4 |
1302 | .RS 4 |
1257 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1303 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1258 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1304 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1259 | In this configuration the watcher triggers an event at the wallclock time |
1305 | In this configuration the watcher triggers an event at the wallclock time |
1260 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1306 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1261 | that is, if it is to be run at January 1st 2011 then it will run when the |
1307 | that is, if it is to be run at January 1st 2011 then it will run when the |
1262 | system time reaches or surpasses this time. |
1308 | system time reaches or surpasses this time. |
1263 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1309 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1264 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1310 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1265 | In this mode the watcher will always be scheduled to time out at the next |
1311 | In this mode the watcher will always be scheduled to time out at the next |
1266 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1312 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1267 | of any time jumps. |
1313 | and then repeat, regardless of any time jumps. |
1268 | .Sp |
1314 | .Sp |
1269 | This can be used to create timers that do not drift with respect to system |
1315 | This can be used to create timers that do not drift with respect to system |
1270 | time: |
1316 | time: |
1271 | .Sp |
1317 | .Sp |
1272 | .Vb 1 |
1318 | .Vb 1 |
… | |
… | |
1279 | by 3600. |
1325 | by 3600. |
1280 | .Sp |
1326 | .Sp |
1281 | Another way to think about it (for the mathematically inclined) is that |
1327 | Another way to think about it (for the mathematically inclined) is that |
1282 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1328 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1283 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1329 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1330 | .Sp |
|
|
1331 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1332 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1333 | this value. |
1284 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1334 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1285 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1335 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1286 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1336 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1287 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1337 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1288 | reschedule callback will be called with the watcher as first, and the |
1338 | reschedule callback will be called with the watcher as first, and the |
1289 | current time as second argument. |
1339 | current time as second argument. |
1290 | .Sp |
1340 | .Sp |
1291 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1341 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1292 | ever, or make any event loop modifications\fR. If you need to stop it, |
1342 | ever, or make any event loop modifications\fR. If you need to stop it, |
1293 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1343 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1294 | starting a prepare watcher). |
1344 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1295 | .Sp |
1345 | .Sp |
1296 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1346 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1297 | ev_tstamp now)\*(C'\fR, e.g.: |
1347 | ev_tstamp now)\*(C'\fR, e.g.: |
1298 | .Sp |
1348 | .Sp |
1299 | .Vb 4 |
1349 | .Vb 4 |
… | |
… | |
1323 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1373 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1324 | Simply stops and restarts the periodic watcher again. This is only useful |
1374 | Simply stops and restarts the periodic watcher again. This is only useful |
1325 | when you changed some parameters or the reschedule callback would return |
1375 | when you changed some parameters or the reschedule callback would return |
1326 | a different time than the last time it was called (e.g. in a crond like |
1376 | a different time than the last time it was called (e.g. in a crond like |
1327 | program when the crontabs have changed). |
1377 | program when the crontabs have changed). |
|
|
1378 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1379 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1380 | When repeating, this contains the offset value, otherwise this is the |
|
|
1381 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1382 | .Sp |
|
|
1383 | Can be modified any time, but changes only take effect when the periodic |
|
|
1384 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1328 | .IP "ev_tstamp interval [read\-write]" 4 |
1385 | .IP "ev_tstamp interval [read\-write]" 4 |
1329 | .IX Item "ev_tstamp interval [read-write]" |
1386 | .IX Item "ev_tstamp interval [read-write]" |
1330 | The current interval value. Can be modified any time, but changes only |
1387 | The current interval value. Can be modified any time, but changes only |
1331 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1388 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1332 | called. |
1389 | called. |
1333 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1390 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1334 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1391 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1335 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1392 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1336 | switched off. Can be changed any time, but changes only take effect when |
1393 | switched off. Can be changed any time, but changes only take effect when |
1337 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1394 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1395 | .IP "ev_tstamp at [read\-only]" 4 |
|
|
1396 | .IX Item "ev_tstamp at [read-only]" |
|
|
1397 | When active, contains the absolute time that the watcher is supposed to |
|
|
1398 | trigger next. |
1338 | .PP |
1399 | .PP |
1339 | Example: Call a callback every hour, or, more precisely, whenever the |
1400 | Example: Call a callback every hour, or, more precisely, whenever the |
1340 | system clock is divisible by 3600. The callback invocation times have |
1401 | system clock is divisible by 3600. The callback invocation times have |
1341 | potentially a lot of jittering, but good long-term stability. |
1402 | potentially a lot of jittering, but good long-term stability. |
1342 | .PP |
1403 | .PP |
… | |
… | |
1392 | first watcher gets started will libev actually register a signal watcher |
1453 | first watcher gets started will libev actually register a signal watcher |
1393 | with the kernel (thus it coexists with your own signal handlers as long |
1454 | with the kernel (thus it coexists with your own signal handlers as long |
1394 | as you don't register any with libev). Similarly, when the last signal |
1455 | as you don't register any with libev). Similarly, when the last signal |
1395 | watcher for a signal is stopped libev will reset the signal handler to |
1456 | watcher for a signal is stopped libev will reset the signal handler to |
1396 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1457 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1458 | .PP |
|
|
1459 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1460 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1397 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1461 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1398 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1462 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1399 | .PD 0 |
1463 | .PD 0 |
1400 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1464 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1401 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1465 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
… | |
… | |
1408 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1472 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1409 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1473 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1410 | .IX Subsection "ev_child - watch out for process status changes" |
1474 | .IX Subsection "ev_child - watch out for process status changes" |
1411 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1475 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1412 | some child status changes (most typically when a child of yours dies). |
1476 | some child status changes (most typically when a child of yours dies). |
|
|
1477 | .PP |
|
|
1478 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1479 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1413 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1480 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1414 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1481 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1415 | .PD 0 |
1482 | .PD 0 |
1416 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1483 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1417 | .IX Item "ev_child_set (ev_child *, int pid)" |
1484 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1482 | reader). Inotify will be used to give hints only and should not change the |
1549 | reader). Inotify will be used to give hints only and should not change the |
1483 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1550 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1484 | to fall back to regular polling again even with inotify, but changes are |
1551 | to fall back to regular polling again even with inotify, but changes are |
1485 | usually detected immediately, and if the file exists there will be no |
1552 | usually detected immediately, and if the file exists there will be no |
1486 | polling. |
1553 | polling. |
|
|
1554 | .PP |
|
|
1555 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1556 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1487 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1557 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1488 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1558 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1489 | .PD 0 |
1559 | .PD 0 |
1490 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1560 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1491 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1561 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
1570 | .PP |
1640 | .PP |
1571 | Apart from keeping your process non-blocking (which is a useful |
1641 | Apart from keeping your process non-blocking (which is a useful |
1572 | effect on its own sometimes), idle watchers are a good place to do |
1642 | effect on its own sometimes), idle watchers are a good place to do |
1573 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1643 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1574 | event loop has handled all outstanding events. |
1644 | event loop has handled all outstanding events. |
|
|
1645 | .PP |
|
|
1646 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1647 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1575 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1648 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1576 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1649 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1577 | Initialises and configures the idle watcher \- it has no parameters of any |
1650 | Initialises and configures the idle watcher \- it has no parameters of any |
1578 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1651 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1579 | believe me. |
1652 | believe me. |
… | |
… | |
1634 | are ready to run (it's actually more complicated: it only runs coroutines |
1707 | are ready to run (it's actually more complicated: it only runs coroutines |
1635 | with priority higher than or equal to the event loop and one coroutine |
1708 | with priority higher than or equal to the event loop and one coroutine |
1636 | of lower priority, but only once, using idle watchers to keep the event |
1709 | of lower priority, but only once, using idle watchers to keep the event |
1637 | loop from blocking if lower-priority coroutines are active, thus mapping |
1710 | loop from blocking if lower-priority coroutines are active, thus mapping |
1638 | low-priority coroutines to idle/background tasks). |
1711 | low-priority coroutines to idle/background tasks). |
|
|
1712 | .PP |
|
|
1713 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1714 | priority, to ensure that they are being run before any other watchers |
|
|
1715 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1716 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1717 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1718 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1719 | loops those other event loops might be in an unusable state until their |
|
|
1720 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1721 | others). |
|
|
1722 | .PP |
|
|
1723 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1724 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1639 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1725 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1640 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1726 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1641 | .PD 0 |
1727 | .PD 0 |
1642 | .IP "ev_check_init (ev_check *, callback)" 4 |
1728 | .IP "ev_check_init (ev_check *, callback)" 4 |
1643 | .IX Item "ev_check_init (ev_check *, callback)" |
1729 | .IX Item "ev_check_init (ev_check *, callback)" |
… | |
… | |
1890 | \& ev_embed_start (loop_hi, &embed); |
1976 | \& ev_embed_start (loop_hi, &embed); |
1891 | \& } |
1977 | \& } |
1892 | \& else |
1978 | \& else |
1893 | \& loop_lo = loop_hi; |
1979 | \& loop_lo = loop_hi; |
1894 | .Ve |
1980 | .Ve |
|
|
1981 | .PP |
|
|
1982 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1983 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1895 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1984 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1896 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1985 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1897 | .PD 0 |
1986 | .PD 0 |
1898 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1987 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1899 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1988 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1919 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
2008 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
1920 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
2009 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
1921 | and only in the child after the fork. If whoever good citizen calling |
2010 | and only in the child after the fork. If whoever good citizen calling |
1922 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
2011 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
1923 | handlers will be invoked, too, of course. |
2012 | handlers will be invoked, too, of course. |
|
|
2013 | .PP |
|
|
2014 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2015 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1924 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2016 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
1925 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2017 | .IX Item "ev_fork_init (ev_signal *, callback)" |
1926 | Initialises and configures the fork watcher \- it has no parameters of any |
2018 | Initialises and configures the fork watcher \- it has no parameters of any |
1927 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
2019 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
1928 | believe me. |
2020 | believe me. |
… | |
… | |
2122 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
2214 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
2123 | constructor already stores the event loop. |
2215 | constructor already stores the event loop. |
2124 | .IP "w\->stop ()" 4 |
2216 | .IP "w\->stop ()" 4 |
2125 | .IX Item "w->stop ()" |
2217 | .IX Item "w->stop ()" |
2126 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2218 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2127 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2219 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
2128 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2220 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
2129 | .IX Item "w->again () ev::timer, ev::periodic only" |
2221 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
2130 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2222 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2131 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2223 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2132 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2224 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
2133 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2225 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
2134 | .IX Item "w->sweep () ev::embed only" |
2226 | .IX Item "w->sweep () (ev::embed only)" |
2135 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2227 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2136 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
2228 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
2137 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
2229 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
2138 | .IX Item "w->update () ev::stat only" |
2230 | .IX Item "w->update () (ev::stat only)" |
2139 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2231 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2140 | .RE |
2232 | .RE |
2141 | .RS 4 |
2233 | .RS 4 |
2142 | .RE |
2234 | .RE |
2143 | .PP |
2235 | .PP |
… | |
… | |
2167 | \& io.start (fd, ev::READ); |
2259 | \& io.start (fd, ev::READ); |
2168 | \& } |
2260 | \& } |
2169 | .Ve |
2261 | .Ve |
2170 | .SH "MACRO MAGIC" |
2262 | .SH "MACRO MAGIC" |
2171 | .IX Header "MACRO MAGIC" |
2263 | .IX Header "MACRO MAGIC" |
2172 | Libev can be compiled with a variety of options, the most fundemantal is |
2264 | Libev can be compiled with a variety of options, the most fundamantal |
2173 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
2265 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
2174 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2266 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2175 | .PP |
2267 | .PP |
2176 | To make it easier to write programs that cope with either variant, the |
2268 | To make it easier to write programs that cope with either variant, the |
2177 | following macros are defined: |
2269 | following macros are defined: |
2178 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2270 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2179 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
2271 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
… | |
… | |
2537 | and the way callbacks are invoked and set. Must expand to a struct member |
2629 | and the way callbacks are invoked and set. Must expand to a struct member |
2538 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2630 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2539 | their default definitions. One possible use for overriding these is to |
2631 | their default definitions. One possible use for overriding these is to |
2540 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2632 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2541 | method calls instead of plain function calls in \*(C+. |
2633 | method calls instead of plain function calls in \*(C+. |
|
|
2634 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
|
|
2635 | .IX Subsection "EXPORTED API SYMBOLS" |
|
|
2636 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
|
|
2637 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
|
|
2638 | all public symbols, one per line: |
|
|
2639 | .Sp |
|
|
2640 | .Vb 2 |
|
|
2641 | \& Symbols.ev for libev proper |
|
|
2642 | \& Symbols.event for the libevent emulation |
|
|
2643 | .Ve |
|
|
2644 | .Sp |
|
|
2645 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2646 | multiple versions of libev linked together (which is obviously bad in |
|
|
2647 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2648 | .Sp |
|
|
2649 | A sed comamnd like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
|
|
2650 | include before including \fIev.h\fR: |
|
|
2651 | .Sp |
|
|
2652 | .Vb 1 |
|
|
2653 | \& <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2654 | .Ve |
|
|
2655 | .Sp |
|
|
2656 | This would create a file \fIwrap.h\fR which essentially looks like this: |
|
|
2657 | .Sp |
|
|
2658 | .Vb 4 |
|
|
2659 | \& #define ev_backend myprefix_ev_backend |
|
|
2660 | \& #define ev_check_start myprefix_ev_check_start |
|
|
2661 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2662 | \& ... |
|
|
2663 | .Ve |
2542 | .Sh "\s-1EXAMPLES\s0" |
2664 | .Sh "\s-1EXAMPLES\s0" |
2543 | .IX Subsection "EXAMPLES" |
2665 | .IX Subsection "EXAMPLES" |
2544 | For a real-world example of a program the includes libev |
2666 | For a real-world example of a program the includes libev |
2545 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2667 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2546 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2668 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |