… | |
… | |
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 "2007-12-07" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-09" "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 |
… | |
… | |
196 | \& return 0; |
196 | \& return 0; |
197 | \& } |
197 | \& } |
198 | .Ve |
198 | .Ve |
199 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
|
|
201 | The newest version of this document is also available as a html-formatted |
|
|
202 | web page you might find easier to navigate when reading it for the first |
|
|
203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
|
|
204 | .PP |
201 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
202 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occuring), and it will manage |
203 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
204 | .PP |
208 | .PP |
205 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
… | |
… | |
255 | .IX Item "int ev_version_major ()" |
259 | .IX Item "int ev_version_major ()" |
256 | .PD 0 |
260 | .PD 0 |
257 | .IP "int ev_version_minor ()" 4 |
261 | .IP "int ev_version_minor ()" 4 |
258 | .IX Item "int ev_version_minor ()" |
262 | .IX Item "int ev_version_minor ()" |
259 | .PD |
263 | .PD |
260 | You can find out the major and minor version numbers of the library |
264 | You can find out the major and minor \s-1ABI\s0 version numbers of the library |
261 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
265 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
262 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
266 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
263 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
267 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
264 | version of the library your program was compiled against. |
268 | version of the library your program was compiled against. |
265 | .Sp |
269 | .Sp |
|
|
270 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
|
|
271 | release version. |
|
|
272 | .Sp |
266 | Usually, it's a good idea to terminate if the major versions mismatch, |
273 | Usually, it's a good idea to terminate if the major versions mismatch, |
267 | as this indicates an incompatible change. Minor versions are usually |
274 | as this indicates an incompatible change. Minor versions are usually |
268 | compatible to older versions, so a larger minor version alone is usually |
275 | compatible to older versions, so a larger minor version alone is usually |
269 | not a problem. |
276 | not a problem. |
270 | .Sp |
277 | .Sp |
271 | Example: Make sure we haven't accidentally been linked against the wrong |
278 | Example: Make sure we haven't accidentally been linked against the wrong |
272 | version. |
279 | version. |
… | |
… | |
630 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
637 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
631 | usually a better approach for this kind of thing. |
638 | usually a better approach for this kind of thing. |
632 | .Sp |
639 | .Sp |
633 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
640 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
634 | .Sp |
641 | .Sp |
635 | .Vb 18 |
642 | .Vb 19 |
|
|
643 | \& - Before the first iteration, call any pending watchers. |
636 | \& * If there are no active watchers (reference count is zero), return. |
644 | \& * If there are no active watchers (reference count is zero), return. |
637 | \& - Queue prepare watchers and then call all outstanding watchers. |
645 | \& - Queue all prepare watchers and then call all outstanding watchers. |
638 | \& - If we have been forked, recreate the kernel state. |
646 | \& - If we have been forked, recreate the kernel state. |
639 | \& - Update the kernel state with all outstanding changes. |
647 | \& - Update the kernel state with all outstanding changes. |
640 | \& - Update the "event loop time". |
648 | \& - Update the "event loop time". |
641 | \& - Calculate for how long to block. |
649 | \& - Calculate for how long to block. |
642 | \& - Block the process, waiting for any events. |
650 | \& - Block the process, waiting for any events. |
… | |
… | |
885 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
893 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
886 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
894 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
887 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
895 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
888 | events but its callback has not yet been invoked). As long as a watcher |
896 | events but its callback has not yet been invoked). As long as a watcher |
889 | is pending (but not active) you must not call an init function on it (but |
897 | is pending (but not active) you must not call an init function on it (but |
890 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
898 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
891 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
899 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
900 | it). |
892 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
901 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
893 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
902 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
894 | Returns the callback currently set on the watcher. |
903 | Returns the callback currently set on the watcher. |
895 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
904 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
896 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
905 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
… | |
… | |
914 | watchers on the same event and make sure one is called first. |
923 | watchers on the same event and make sure one is called first. |
915 | .Sp |
924 | .Sp |
916 | If you need to suppress invocation when higher priority events are pending |
925 | If you need to suppress invocation when higher priority events are pending |
917 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
926 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
918 | .Sp |
927 | .Sp |
|
|
928 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
929 | pending. |
|
|
930 | .Sp |
919 | The default priority used by watchers when no priority has been set is |
931 | The default priority used by watchers when no priority has been set is |
920 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
932 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
921 | .Sp |
933 | .Sp |
922 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
934 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
923 | fine, as long as you do not mind that the priority value you query might |
935 | fine, as long as you do not mind that the priority value you query might |
924 | or might not have been adjusted to be within valid range. |
936 | or might not have been adjusted to be within valid range. |
|
|
937 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
938 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
939 | Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither |
|
|
940 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
941 | can deal with that fact. |
|
|
942 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
943 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
944 | If the watcher is pending, this function returns clears its pending status |
|
|
945 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
946 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
925 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
947 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
926 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
948 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
927 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
949 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
928 | and read at any time, libev will completely ignore it. This can be used |
950 | and read at any time, libev will completely ignore it. This can be used |
929 | to associate arbitrary data with your watcher. If you need more data and |
951 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
1216 | but on wallclock time (absolute time). You can tell a periodic watcher |
1238 | but on wallclock time (absolute time). You can tell a periodic watcher |
1217 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1239 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1218 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1240 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1219 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1241 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1220 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1242 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1221 | roughly 10 seconds later and of course not if you reset your system time |
1243 | roughly 10 seconds later). |
1222 | again). |
|
|
1223 | .PP |
1244 | .PP |
1224 | They can also be used to implement vastly more complex timers, such as |
1245 | They can also be used to implement vastly more complex timers, such as |
1225 | triggering an event on eahc midnight, local time. |
1246 | triggering an event on each midnight, local time or other, complicated, |
|
|
1247 | rules. |
1226 | .PP |
1248 | .PP |
1227 | As with timers, the callback is guarenteed to be invoked only when the |
1249 | As with timers, the callback is guarenteed to be invoked only when the |
1228 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1250 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1229 | during the same loop iteration then order of execution is undefined. |
1251 | during the same loop iteration then order of execution is undefined. |
1230 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1252 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
… | |
… | |
1234 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1256 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1235 | .PD |
1257 | .PD |
1236 | Lots of arguments, lets sort it out... There are basically three modes of |
1258 | Lots of arguments, lets sort it out... There are basically three modes of |
1237 | operation, and we will explain them from simplest to complex: |
1259 | operation, and we will explain them from simplest to complex: |
1238 | .RS 4 |
1260 | .RS 4 |
1239 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1261 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1240 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1262 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1241 | In this configuration the watcher triggers an event at the wallclock time |
1263 | In this configuration the watcher triggers an event at the wallclock time |
1242 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1264 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1243 | that is, if it is to be run at January 1st 2011 then it will run when the |
1265 | that is, if it is to be run at January 1st 2011 then it will run when the |
1244 | system time reaches or surpasses this time. |
1266 | system time reaches or surpasses this time. |
1245 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1267 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1246 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1268 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1247 | In this mode the watcher will always be scheduled to time out at the next |
1269 | In this mode the watcher will always be scheduled to time out at the next |
1248 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1270 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1249 | of any time jumps. |
1271 | and then repeat, regardless of any time jumps. |
1250 | .Sp |
1272 | .Sp |
1251 | This can be used to create timers that do not drift with respect to system |
1273 | This can be used to create timers that do not drift with respect to system |
1252 | time: |
1274 | time: |
1253 | .Sp |
1275 | .Sp |
1254 | .Vb 1 |
1276 | .Vb 1 |
… | |
… | |
1261 | by 3600. |
1283 | by 3600. |
1262 | .Sp |
1284 | .Sp |
1263 | Another way to think about it (for the mathematically inclined) is that |
1285 | Another way to think about it (for the mathematically inclined) is that |
1264 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1286 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1265 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1287 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1288 | .Sp |
|
|
1289 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1290 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1291 | this value. |
1266 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1292 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1267 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1293 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1268 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1294 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1269 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1295 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1270 | reschedule callback will be called with the watcher as first, and the |
1296 | reschedule callback will be called with the watcher as first, and the |
1271 | current time as second argument. |
1297 | current time as second argument. |
1272 | .Sp |
1298 | .Sp |
1273 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1299 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1274 | ever, or make any event loop modifications\fR. If you need to stop it, |
1300 | ever, or make any event loop modifications\fR. If you need to stop it, |
1275 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1301 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1276 | starting a prepare watcher). |
1302 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1277 | .Sp |
1303 | .Sp |
1278 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1304 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1279 | ev_tstamp now)\*(C'\fR, e.g.: |
1305 | ev_tstamp now)\*(C'\fR, e.g.: |
1280 | .Sp |
1306 | .Sp |
1281 | .Vb 4 |
1307 | .Vb 4 |
… | |
… | |
1305 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1331 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1306 | Simply stops and restarts the periodic watcher again. This is only useful |
1332 | Simply stops and restarts the periodic watcher again. This is only useful |
1307 | when you changed some parameters or the reschedule callback would return |
1333 | when you changed some parameters or the reschedule callback would return |
1308 | a different time than the last time it was called (e.g. in a crond like |
1334 | a different time than the last time it was called (e.g. in a crond like |
1309 | program when the crontabs have changed). |
1335 | program when the crontabs have changed). |
|
|
1336 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1337 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1338 | When repeating, this contains the offset value, otherwise this is the |
|
|
1339 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1340 | .Sp |
|
|
1341 | Can be modified any time, but changes only take effect when the periodic |
|
|
1342 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1310 | .IP "ev_tstamp interval [read\-write]" 4 |
1343 | .IP "ev_tstamp interval [read\-write]" 4 |
1311 | .IX Item "ev_tstamp interval [read-write]" |
1344 | .IX Item "ev_tstamp interval [read-write]" |
1312 | The current interval value. Can be modified any time, but changes only |
1345 | The current interval value. Can be modified any time, but changes only |
1313 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1346 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1314 | called. |
1347 | called. |
… | |
… | |
1616 | are ready to run (it's actually more complicated: it only runs coroutines |
1649 | are ready to run (it's actually more complicated: it only runs coroutines |
1617 | with priority higher than or equal to the event loop and one coroutine |
1650 | with priority higher than or equal to the event loop and one coroutine |
1618 | of lower priority, but only once, using idle watchers to keep the event |
1651 | of lower priority, but only once, using idle watchers to keep the event |
1619 | loop from blocking if lower-priority coroutines are active, thus mapping |
1652 | loop from blocking if lower-priority coroutines are active, thus mapping |
1620 | low-priority coroutines to idle/background tasks). |
1653 | low-priority coroutines to idle/background tasks). |
|
|
1654 | .PP |
|
|
1655 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1656 | priority, to ensure that they are being run before any other watchers |
|
|
1657 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1658 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1659 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1660 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1661 | loops those other event loops might be in an unusable state until their |
|
|
1662 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1663 | others). |
1621 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1664 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1622 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1665 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1623 | .PD 0 |
1666 | .PD 0 |
1624 | .IP "ev_check_init (ev_check *, callback)" 4 |
1667 | .IP "ev_check_init (ev_check *, callback)" 4 |
1625 | .IX Item "ev_check_init (ev_check *, callback)" |
1668 | .IX Item "ev_check_init (ev_check *, callback)" |
1626 | .PD |
1669 | .PD |
1627 | Initialises and configures the prepare or check watcher \- they have no |
1670 | Initialises and configures the prepare or check watcher \- they have no |
1628 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1671 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1629 | macros, but using them is utterly, utterly and completely pointless. |
1672 | macros, but using them is utterly, utterly and completely pointless. |
1630 | .PP |
1673 | .PP |
1631 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1674 | There are a number of principal ways to embed other event loops or modules |
1632 | and a timeout watcher in a prepare handler, as required by libadns, and |
1675 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1676 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1677 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1678 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1679 | into the Glib event loop). |
|
|
1680 | .PP |
|
|
1681 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1633 | in a check watcher, destroy them and call into libadns. What follows is |
1682 | and in a check watcher, destroy them and call into libadns. What follows |
1634 | pseudo-code only of course: |
1683 | is pseudo-code only of course. This requires you to either use a low |
|
|
1684 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1685 | the callbacks for the IO/timeout watchers might not have been called yet. |
1635 | .PP |
1686 | .PP |
1636 | .Vb 2 |
1687 | .Vb 2 |
1637 | \& static ev_io iow [nfd]; |
1688 | \& static ev_io iow [nfd]; |
1638 | \& static ev_timer tw; |
1689 | \& static ev_timer tw; |
1639 | .Ve |
1690 | .Ve |
1640 | .PP |
1691 | .PP |
1641 | .Vb 9 |
1692 | .Vb 4 |
1642 | \& static void |
1693 | \& static void |
1643 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1694 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1644 | \& { |
1695 | \& { |
1645 | \& // set the relevant poll flags |
|
|
1646 | \& // could also call adns_processreadable etc. here |
|
|
1647 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1648 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1649 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1650 | \& } |
1696 | \& } |
1651 | .Ve |
1697 | .Ve |
1652 | .PP |
1698 | .PP |
1653 | .Vb 8 |
1699 | .Vb 8 |
1654 | \& // create io watchers for each fd and a timer before blocking |
1700 | \& // create io watchers for each fd and a timer before blocking |
… | |
… | |
1666 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1712 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1667 | \& ev_timer_start (loop, &tw); |
1713 | \& ev_timer_start (loop, &tw); |
1668 | .Ve |
1714 | .Ve |
1669 | .PP |
1715 | .PP |
1670 | .Vb 6 |
1716 | .Vb 6 |
1671 | \& // create on ev_io per pollfd |
1717 | \& // create one ev_io per pollfd |
1672 | \& for (int i = 0; i < nfd; ++i) |
1718 | \& for (int i = 0; i < nfd; ++i) |
1673 | \& { |
1719 | \& { |
1674 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1720 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1675 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1721 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1676 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1722 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1677 | .Ve |
1723 | .Ve |
1678 | .PP |
1724 | .PP |
1679 | .Vb 5 |
1725 | .Vb 4 |
1680 | \& fds [i].revents = 0; |
1726 | \& fds [i].revents = 0; |
1681 | \& iow [i].data = fds + i; |
|
|
1682 | \& ev_io_start (loop, iow + i); |
1727 | \& ev_io_start (loop, iow + i); |
1683 | \& } |
1728 | \& } |
1684 | \& } |
1729 | \& } |
1685 | .Ve |
1730 | .Ve |
1686 | .PP |
1731 | .PP |
… | |
… | |
1690 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1735 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1691 | \& { |
1736 | \& { |
1692 | \& ev_timer_stop (loop, &tw); |
1737 | \& ev_timer_stop (loop, &tw); |
1693 | .Ve |
1738 | .Ve |
1694 | .PP |
1739 | .PP |
1695 | .Vb 2 |
1740 | .Vb 8 |
1696 | \& for (int i = 0; i < nfd; ++i) |
1741 | \& for (int i = 0; i < nfd; ++i) |
|
|
1742 | \& { |
|
|
1743 | \& // set the relevant poll flags |
|
|
1744 | \& // could also call adns_processreadable etc. here |
|
|
1745 | \& struct pollfd *fd = fds + i; |
|
|
1746 | \& int revents = ev_clear_pending (iow + i); |
|
|
1747 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1748 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1749 | .Ve |
|
|
1750 | .PP |
|
|
1751 | .Vb 3 |
|
|
1752 | \& // now stop the watcher |
1697 | \& ev_io_stop (loop, iow + i); |
1753 | \& ev_io_stop (loop, iow + i); |
|
|
1754 | \& } |
1698 | .Ve |
1755 | .Ve |
1699 | .PP |
1756 | .PP |
1700 | .Vb 2 |
1757 | .Vb 2 |
1701 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1758 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1759 | \& } |
|
|
1760 | .Ve |
|
|
1761 | .PP |
|
|
1762 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1763 | in the prepare watcher and would dispose of the check watcher. |
|
|
1764 | .PP |
|
|
1765 | Method 3: If the module to be embedded supports explicit event |
|
|
1766 | notification (adns does), you can also make use of the actual watcher |
|
|
1767 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1768 | .PP |
|
|
1769 | .Vb 5 |
|
|
1770 | \& static void |
|
|
1771 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1772 | \& { |
|
|
1773 | \& adns_state ads = (adns_state)w->data; |
|
|
1774 | \& update_now (EV_A); |
|
|
1775 | .Ve |
|
|
1776 | .PP |
|
|
1777 | .Vb 2 |
|
|
1778 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1779 | \& } |
|
|
1780 | .Ve |
|
|
1781 | .PP |
|
|
1782 | .Vb 5 |
|
|
1783 | \& static void |
|
|
1784 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1785 | \& { |
|
|
1786 | \& adns_state ads = (adns_state)w->data; |
|
|
1787 | \& update_now (EV_A); |
|
|
1788 | .Ve |
|
|
1789 | .PP |
|
|
1790 | .Vb 3 |
|
|
1791 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1792 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1793 | \& } |
|
|
1794 | .Ve |
|
|
1795 | .PP |
|
|
1796 | .Vb 1 |
|
|
1797 | \& // do not ever call adns_afterpoll |
|
|
1798 | .Ve |
|
|
1799 | .PP |
|
|
1800 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1801 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1802 | their poll function. The drawback with this solution is that the main |
|
|
1803 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1804 | this. |
|
|
1805 | .PP |
|
|
1806 | .Vb 4 |
|
|
1807 | \& static gint |
|
|
1808 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1809 | \& { |
|
|
1810 | \& int got_events = 0; |
|
|
1811 | .Ve |
|
|
1812 | .PP |
|
|
1813 | .Vb 2 |
|
|
1814 | \& for (n = 0; n < nfds; ++n) |
|
|
1815 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1816 | .Ve |
|
|
1817 | .PP |
|
|
1818 | .Vb 2 |
|
|
1819 | \& if (timeout >= 0) |
|
|
1820 | \& // create/start timer |
|
|
1821 | .Ve |
|
|
1822 | .PP |
|
|
1823 | .Vb 2 |
|
|
1824 | \& // poll |
|
|
1825 | \& ev_loop (EV_A_ 0); |
|
|
1826 | .Ve |
|
|
1827 | .PP |
|
|
1828 | .Vb 3 |
|
|
1829 | \& // stop timer again |
|
|
1830 | \& if (timeout >= 0) |
|
|
1831 | \& ev_timer_stop (EV_A_ &to); |
|
|
1832 | .Ve |
|
|
1833 | .PP |
|
|
1834 | .Vb 3 |
|
|
1835 | \& // stop io watchers again - their callbacks should have set |
|
|
1836 | \& for (n = 0; n < nfds; ++n) |
|
|
1837 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1838 | .Ve |
|
|
1839 | .PP |
|
|
1840 | .Vb 2 |
|
|
1841 | \& return got_events; |
1702 | \& } |
1842 | \& } |
1703 | .Ve |
1843 | .Ve |
1704 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1844 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1705 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1845 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1706 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1846 | .IX Subsection "ev_embed - when one backend isn't enough..." |
… | |
… | |
1890 | .PP |
2030 | .PP |
1891 | .Vb 1 |
2031 | .Vb 1 |
1892 | \& #include <ev++.h> |
2032 | \& #include <ev++.h> |
1893 | .Ve |
2033 | .Ve |
1894 | .PP |
2034 | .PP |
1895 | (it is not installed by default). This automatically includes \fIev.h\fR |
2035 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1896 | and puts all of its definitions (many of them macros) into the global |
2036 | of them macros) into the global namespace. All \*(C+ specific things are |
1897 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2037 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2038 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1898 | .PP |
2039 | .PP |
1899 | It should support all the same embedding options as \fIev.h\fR, most notably |
2040 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1900 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2041 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2042 | that the watcher is associated with (or no additional members at all if |
|
|
2043 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2044 | .PP |
|
|
2045 | Currently, functions, and static and non-static member functions can be |
|
|
2046 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2047 | need one additional pointer for context. If you need support for other |
|
|
2048 | types of functors please contact the author (preferably after implementing |
|
|
2049 | it). |
1901 | .PP |
2050 | .PP |
1902 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2051 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1903 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2052 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1904 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2053 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1905 | .IX Item "ev::READ, ev::WRITE etc." |
2054 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1917 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2066 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1918 | defines by many implementations. |
2067 | defines by many implementations. |
1919 | .Sp |
2068 | .Sp |
1920 | All of those classes have these methods: |
2069 | All of those classes have these methods: |
1921 | .RS 4 |
2070 | .RS 4 |
1922 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2071 | .IP "ev::TYPE::TYPE ()" 4 |
1923 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2072 | .IX Item "ev::TYPE::TYPE ()" |
1924 | .PD 0 |
2073 | .PD 0 |
1925 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2074 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1926 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2075 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1927 | .IP "ev::TYPE::~TYPE" 4 |
2076 | .IP "ev::TYPE::~TYPE" 4 |
1928 | .IX Item "ev::TYPE::~TYPE" |
2077 | .IX Item "ev::TYPE::~TYPE" |
1929 | .PD |
2078 | .PD |
1930 | The constructor takes a pointer to an object and a method pointer to |
2079 | The constructor (optionally) takes an event loop to associate the watcher |
1931 | the event handler callback to call in this class. The constructor calls |
2080 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1932 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2081 | .Sp |
1933 | before starting it. If you do not specify a loop then the constructor |
2082 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1934 | automatically associates the default loop with this watcher. |
2083 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2084 | .Sp |
|
|
2085 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2086 | method to set a callback before you can start the watcher. |
|
|
2087 | .Sp |
|
|
2088 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2089 | not allow explicit template arguments for constructors). |
1935 | .Sp |
2090 | .Sp |
1936 | The destructor automatically stops the watcher if it is active. |
2091 | The destructor automatically stops the watcher if it is active. |
|
|
2092 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2093 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2094 | This method sets the callback method to call. The method has to have a |
|
|
2095 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2096 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2097 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2098 | .Sp |
|
|
2099 | This method synthesizes efficient thunking code to call your method from |
|
|
2100 | the C callback that libev requires. If your compiler can inline your |
|
|
2101 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2102 | your compiler is good :), then the method will be fully inlined into the |
|
|
2103 | thunking function, making it as fast as a direct C callback. |
|
|
2104 | .Sp |
|
|
2105 | Example: simple class declaration and watcher initialisation |
|
|
2106 | .Sp |
|
|
2107 | .Vb 4 |
|
|
2108 | \& struct myclass |
|
|
2109 | \& { |
|
|
2110 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2111 | \& } |
|
|
2112 | .Ve |
|
|
2113 | .Sp |
|
|
2114 | .Vb 3 |
|
|
2115 | \& myclass obj; |
|
|
2116 | \& ev::io iow; |
|
|
2117 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2118 | .Ve |
|
|
2119 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2120 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2121 | Also sets a callback, but uses a static method or plain function as |
|
|
2122 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2123 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2124 | .Sp |
|
|
2125 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2126 | .Sp |
|
|
2127 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2128 | .Sp |
|
|
2129 | Example: |
|
|
2130 | .Sp |
|
|
2131 | .Vb 2 |
|
|
2132 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2133 | \& iow.set <io_cb> (); |
|
|
2134 | .Ve |
1937 | .IP "w\->set (struct ev_loop *)" 4 |
2135 | .IP "w\->set (struct ev_loop *)" 4 |
1938 | .IX Item "w->set (struct ev_loop *)" |
2136 | .IX Item "w->set (struct ev_loop *)" |
1939 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2137 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1940 | do this when the watcher is inactive (and not pending either). |
2138 | do this when the watcher is inactive (and not pending either). |
1941 | .IP "w\->set ([args])" 4 |
2139 | .IP "w\->set ([args])" 4 |
1942 | .IX Item "w->set ([args])" |
2140 | .IX Item "w->set ([args])" |
1943 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2141 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1944 | called at least once. Unlike the C counterpart, an active watcher gets |
2142 | called at least once. Unlike the C counterpart, an active watcher gets |
1945 | automatically stopped and restarted. |
2143 | automatically stopped and restarted when reconfiguring it with this |
|
|
2144 | method. |
1946 | .IP "w\->start ()" 4 |
2145 | .IP "w\->start ()" 4 |
1947 | .IX Item "w->start ()" |
2146 | .IX Item "w->start ()" |
1948 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2147 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1949 | constructor already takes the loop. |
2148 | constructor already stores the event loop. |
1950 | .IP "w\->stop ()" 4 |
2149 | .IP "w\->stop ()" 4 |
1951 | .IX Item "w->stop ()" |
2150 | .IX Item "w->stop ()" |
1952 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2151 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1953 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2152 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1954 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2153 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1980 | .Vb 2 |
2179 | .Vb 2 |
1981 | \& myclass (); |
2180 | \& myclass (); |
1982 | \& } |
2181 | \& } |
1983 | .Ve |
2182 | .Ve |
1984 | .PP |
2183 | .PP |
1985 | .Vb 6 |
2184 | .Vb 4 |
1986 | \& myclass::myclass (int fd) |
2185 | \& myclass::myclass (int fd) |
1987 | \& : io (this, &myclass::io_cb), |
|
|
1988 | \& idle (this, &myclass::idle_cb) |
|
|
1989 | \& { |
2186 | \& { |
|
|
2187 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2188 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2189 | .Ve |
|
|
2190 | .PP |
|
|
2191 | .Vb 2 |
1990 | \& io.start (fd, ev::READ); |
2192 | \& io.start (fd, ev::READ); |
1991 | \& } |
2193 | \& } |
1992 | .Ve |
2194 | .Ve |
1993 | .SH "MACRO MAGIC" |
2195 | .SH "MACRO MAGIC" |
1994 | .IX Header "MACRO MAGIC" |
2196 | .IX Header "MACRO MAGIC" |
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2274 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2476 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2275 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2477 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2276 | additional independent event loops. Otherwise there will be no support |
2478 | additional independent event loops. Otherwise there will be no support |
2277 | for multiple event loops and there is no first event loop pointer |
2479 | for multiple event loops and there is no first event loop pointer |
2278 | argument. Instead, all functions act on the single default loop. |
2480 | argument. Instead, all functions act on the single default loop. |
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2481 | .IP "\s-1EV_MINPRI\s0" 4 |
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2482 | .IX Item "EV_MINPRI" |
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2483 | .PD 0 |
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2484 | .IP "\s-1EV_MAXPRI\s0" 4 |
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2485 | .IX Item "EV_MAXPRI" |
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2486 | .PD |
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2487 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
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2488 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
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2489 | provide for more priorities by overriding those symbols (usually defined |
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2490 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
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2491 | .Sp |
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2492 | When doing priority-based operations, libev usually has to linearly search |
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2493 | all the priorities, so having many of them (hundreds) uses a lot of space |
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2494 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
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2495 | fine. |
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2496 | .Sp |
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2497 | If your embedding app does not need any priorities, defining these both to |
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2498 | \&\f(CW0\fR will save some memory and cpu. |
2279 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2499 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2280 | .IX Item "EV_PERIODIC_ENABLE" |
2500 | .IX Item "EV_PERIODIC_ENABLE" |
2281 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2501 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2282 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2502 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2283 | code. |
2503 | code. |
… | |
… | |
2382 | .SH "COMPLEXITIES" |
2602 | .SH "COMPLEXITIES" |
2383 | .IX Header "COMPLEXITIES" |
2603 | .IX Header "COMPLEXITIES" |
2384 | In this section the complexities of (many of) the algorithms used inside |
2604 | In this section the complexities of (many of) the algorithms used inside |
2385 | libev will be explained. For complexity discussions about backends see the |
2605 | libev will be explained. For complexity discussions about backends see the |
2386 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2606 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
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2607 | .Sp |
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2608 | All of the following are about amortised time: If an array needs to be |
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2609 | extended, libev needs to realloc and move the whole array, but this |
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2610 | happens asymptotically never with higher number of elements, so O(1) might |
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2611 | mean it might do a lengthy realloc operation in rare cases, but on average |
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2612 | it is much faster and asymptotically approaches constant time. |
2387 | .RS 4 |
2613 | .RS 4 |
2388 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2614 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2389 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2615 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2390 | .PD 0 |
2616 | This means that, when you have a watcher that triggers in one hour and |
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2617 | there are 100 watchers that would trigger before that then inserting will |
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2618 | have to skip those 100 watchers. |
2391 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2619 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2392 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2620 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
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2621 | That means that for changing a timer costs less than removing/adding them |
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2622 | as only the relative motion in the event queue has to be paid for. |
2393 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2623 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2394 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2624 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2395 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2625 | These just add the watcher into an array or at the head of a list. |
2396 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2626 | =item Stopping check/prepare/idle watchers: O(1) |
2397 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2627 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2398 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2628 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
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2629 | These watchers are stored in lists then need to be walked to find the |
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2630 | correct watcher to remove. The lists are usually short (you don't usually |
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2631 | have many watchers waiting for the same fd or signal). |
2399 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2632 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2400 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2633 | .IX Item "Finding the next timer per loop iteration: O(1)" |
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2634 | .PD 0 |
2401 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2635 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2402 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2636 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
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2637 | .PD |
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2638 | A change means an I/O watcher gets started or stopped, which requires |
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2639 | libev to recalculate its status (and possibly tell the kernel). |
2403 | .IP "Activating one watcher: O(1)" 4 |
2640 | .IP "Activating one watcher: O(1)" 4 |
2404 | .IX Item "Activating one watcher: O(1)" |
2641 | .IX Item "Activating one watcher: O(1)" |
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2642 | .PD 0 |
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2643 | .IP "Priority handling: O(number_of_priorities)" 4 |
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2644 | .IX Item "Priority handling: O(number_of_priorities)" |
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2645 | .PD |
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2646 | Priorities are implemented by allocating some space for each |
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2647 | priority. When doing priority-based operations, libev usually has to |
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2648 | linearly search all the priorities. |
2405 | .RE |
2649 | .RE |
2406 | .RS 4 |
2650 | .RS 4 |
2407 | .PD |
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2408 | .SH "AUTHOR" |
2651 | .SH "AUTHOR" |
2409 | .IX Header "AUTHOR" |
2652 | .IX Header "AUTHOR" |
2410 | Marc Lehmann <libev@schmorp.de>. |
2653 | Marc Lehmann <libev@schmorp.de>. |