… | |
… | |
117 | |
117 | |
118 | =item int ev_version_major () |
118 | =item int ev_version_major () |
119 | |
119 | |
120 | =item int ev_version_minor () |
120 | =item int ev_version_minor () |
121 | |
121 | |
122 | You can find out the major and minor version numbers of the library |
122 | You can find out the major and minor ABI version numbers of the library |
123 | you linked against by calling the functions C<ev_version_major> and |
123 | you linked against by calling the functions C<ev_version_major> and |
124 | C<ev_version_minor>. If you want, you can compare against the global |
124 | C<ev_version_minor>. If you want, you can compare against the global |
125 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
125 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
126 | version of the library your program was compiled against. |
126 | version of the library your program was compiled against. |
127 | |
127 | |
|
|
128 | These version numbers refer to the ABI version of the library, not the |
|
|
129 | release version. |
|
|
130 | |
128 | Usually, it's a good idea to terminate if the major versions mismatch, |
131 | Usually, it's a good idea to terminate if the major versions mismatch, |
129 | as this indicates an incompatible change. Minor versions are usually |
132 | as this indicates an incompatible change. Minor versions are usually |
130 | compatible to older versions, so a larger minor version alone is usually |
133 | compatible to older versions, so a larger minor version alone is usually |
131 | not a problem. |
134 | not a problem. |
132 | |
135 | |
133 | Example: Make sure we haven't accidentally been linked against the wrong |
136 | Example: Make sure we haven't accidentally been linked against the wrong |
134 | version. |
137 | version. |
… | |
… | |
486 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
489 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
487 | usually a better approach for this kind of thing. |
490 | usually a better approach for this kind of thing. |
488 | |
491 | |
489 | Here are the gory details of what C<ev_loop> does: |
492 | Here are the gory details of what C<ev_loop> does: |
490 | |
493 | |
|
|
494 | - Before the first iteration, call any pending watchers. |
491 | * If there are no active watchers (reference count is zero), return. |
495 | * If there are no active watchers (reference count is zero), return. |
492 | - Queue prepare watchers and then call all outstanding watchers. |
496 | - Queue all prepare watchers and then call all outstanding watchers. |
493 | - If we have been forked, recreate the kernel state. |
497 | - If we have been forked, recreate the kernel state. |
494 | - Update the kernel state with all outstanding changes. |
498 | - Update the kernel state with all outstanding changes. |
495 | - Update the "event loop time". |
499 | - Update the "event loop time". |
496 | - Calculate for how long to block. |
500 | - Calculate for how long to block. |
497 | - Block the process, waiting for any events. |
501 | - Block the process, waiting for any events. |
… | |
… | |
736 | =item bool ev_is_pending (ev_TYPE *watcher) |
740 | =item bool ev_is_pending (ev_TYPE *watcher) |
737 | |
741 | |
738 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
742 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
739 | events but its callback has not yet been invoked). As long as a watcher |
743 | events but its callback has not yet been invoked). As long as a watcher |
740 | is pending (but not active) you must not call an init function on it (but |
744 | is pending (but not active) you must not call an init function on it (but |
741 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
745 | C<ev_TYPE_set> is safe), you must not change its priority, and you must |
742 | libev (e.g. you cnanot C<free ()> it). |
746 | make sure the watcher is available to libev (e.g. you cannot C<free ()> |
|
|
747 | it). |
743 | |
748 | |
744 | =item callback ev_cb (ev_TYPE *watcher) |
749 | =item callback ev_cb (ev_TYPE *watcher) |
745 | |
750 | |
746 | Returns the callback currently set on the watcher. |
751 | Returns the callback currently set on the watcher. |
747 | |
752 | |
… | |
… | |
766 | watchers on the same event and make sure one is called first. |
771 | watchers on the same event and make sure one is called first. |
767 | |
772 | |
768 | If you need to suppress invocation when higher priority events are pending |
773 | If you need to suppress invocation when higher priority events are pending |
769 | you need to look at C<ev_idle> watchers, which provide this functionality. |
774 | you need to look at C<ev_idle> watchers, which provide this functionality. |
770 | |
775 | |
|
|
776 | You I<must not> change the priority of a watcher as long as it is active or |
|
|
777 | pending. |
|
|
778 | |
771 | The default priority used by watchers when no priority has been set is |
779 | The default priority used by watchers when no priority has been set is |
772 | always C<0>, which is supposed to not be too high and not be too low :). |
780 | always C<0>, which is supposed to not be too high and not be too low :). |
773 | |
781 | |
774 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
782 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
775 | fine, as long as you do not mind that the priority value you query might |
783 | fine, as long as you do not mind that the priority value you query might |
776 | or might not have been adjusted to be within valid range. |
784 | or might not have been adjusted to be within valid range. |
|
|
785 | |
|
|
786 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
|
|
787 | |
|
|
788 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
|
|
789 | C<loop> nor C<revents> need to be valid as long as the watcher callback |
|
|
790 | can deal with that fact. |
|
|
791 | |
|
|
792 | =item int ev_clear_pending (loop, ev_TYPE *watcher) |
|
|
793 | |
|
|
794 | If the watcher is pending, this function returns clears its pending status |
|
|
795 | and returns its C<revents> bitset (as if its callback was invoked). If the |
|
|
796 | watcher isn't pending it does nothing and returns C<0>. |
777 | |
797 | |
778 | =back |
798 | =back |
779 | |
799 | |
780 | |
800 | |
781 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
801 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
891 | play around with an Xlib connection), then you have to seperately re-test |
911 | play around with an Xlib connection), then you have to seperately re-test |
892 | whether a file descriptor is really ready with a known-to-be good interface |
912 | whether a file descriptor is really ready with a known-to-be good interface |
893 | such as poll (fortunately in our Xlib example, Xlib already does this on |
913 | such as poll (fortunately in our Xlib example, Xlib already does this on |
894 | its own, so its quite safe to use). |
914 | its own, so its quite safe to use). |
895 | |
915 | |
|
|
916 | =head3 The special problem of disappearing file descriptors |
|
|
917 | |
|
|
918 | Some backends (e.g kqueue, epoll) need to be told about closing a file |
|
|
919 | descriptor (either by calling C<close> explicitly or by any other means, |
|
|
920 | such as C<dup>). The reason is that you register interest in some file |
|
|
921 | descriptor, but when it goes away, the operating system will silently drop |
|
|
922 | this interest. If another file descriptor with the same number then is |
|
|
923 | registered with libev, there is no efficient way to see that this is, in |
|
|
924 | fact, a different file descriptor. |
|
|
925 | |
|
|
926 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
927 | the following policy: Each time C<ev_io_set> is being called, libev |
|
|
928 | will assume that this is potentially a new file descriptor, otherwise |
|
|
929 | it is assumed that the file descriptor stays the same. That means that |
|
|
930 | you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the |
|
|
931 | descriptor even if the file descriptor number itself did not change. |
|
|
932 | |
|
|
933 | This is how one would do it normally anyway, the important point is that |
|
|
934 | the libev application should not optimise around libev but should leave |
|
|
935 | optimisations to libev. |
|
|
936 | |
|
|
937 | |
|
|
938 | =head3 Watcher-Specific Functions |
|
|
939 | |
896 | =over 4 |
940 | =over 4 |
897 | |
941 | |
898 | =item ev_io_init (ev_io *, callback, int fd, int events) |
942 | =item ev_io_init (ev_io *, callback, int fd, int events) |
899 | |
943 | |
900 | =item ev_io_set (ev_io *, int fd, int events) |
944 | =item ev_io_set (ev_io *, int fd, int events) |
… | |
… | |
952 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
996 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
953 | |
997 | |
954 | The callback is guarenteed to be invoked only when its timeout has passed, |
998 | The callback is guarenteed to be invoked only when its timeout has passed, |
955 | but if multiple timers become ready during the same loop iteration then |
999 | but if multiple timers become ready during the same loop iteration then |
956 | order of execution is undefined. |
1000 | order of execution is undefined. |
|
|
1001 | |
|
|
1002 | =head3 Watcher-Specific Functions and Data Members |
957 | |
1003 | |
958 | =over 4 |
1004 | =over 4 |
959 | |
1005 | |
960 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
1006 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
961 | |
1007 | |
… | |
… | |
1057 | but on wallclock time (absolute time). You can tell a periodic watcher |
1103 | but on wallclock time (absolute time). You can tell a periodic watcher |
1058 | to trigger "at" some specific point in time. For example, if you tell a |
1104 | to trigger "at" some specific point in time. For example, if you tell a |
1059 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1105 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1060 | + 10.>) and then reset your system clock to the last year, then it will |
1106 | + 10.>) and then reset your system clock to the last year, then it will |
1061 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1107 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1062 | roughly 10 seconds later and of course not if you reset your system time |
1108 | roughly 10 seconds later). |
1063 | again). |
|
|
1064 | |
1109 | |
1065 | They can also be used to implement vastly more complex timers, such as |
1110 | They can also be used to implement vastly more complex timers, such as |
1066 | triggering an event on eahc midnight, local time. |
1111 | triggering an event on each midnight, local time or other, complicated, |
|
|
1112 | rules. |
1067 | |
1113 | |
1068 | As with timers, the callback is guarenteed to be invoked only when the |
1114 | As with timers, the callback is guarenteed to be invoked only when the |
1069 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1115 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1070 | during the same loop iteration then order of execution is undefined. |
1116 | during the same loop iteration then order of execution is undefined. |
1071 | |
1117 | |
|
|
1118 | =head3 Watcher-Specific Functions and Data Members |
|
|
1119 | |
1072 | =over 4 |
1120 | =over 4 |
1073 | |
1121 | |
1074 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1122 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1075 | |
1123 | |
1076 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
1124 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
… | |
… | |
1078 | Lots of arguments, lets sort it out... There are basically three modes of |
1126 | Lots of arguments, lets sort it out... There are basically three modes of |
1079 | operation, and we will explain them from simplest to complex: |
1127 | operation, and we will explain them from simplest to complex: |
1080 | |
1128 | |
1081 | =over 4 |
1129 | =over 4 |
1082 | |
1130 | |
1083 | =item * absolute timer (interval = reschedule_cb = 0) |
1131 | =item * absolute timer (at = time, interval = reschedule_cb = 0) |
1084 | |
1132 | |
1085 | In this configuration the watcher triggers an event at the wallclock time |
1133 | In this configuration the watcher triggers an event at the wallclock time |
1086 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1134 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1087 | that is, if it is to be run at January 1st 2011 then it will run when the |
1135 | that is, if it is to be run at January 1st 2011 then it will run when the |
1088 | system time reaches or surpasses this time. |
1136 | system time reaches or surpasses this time. |
1089 | |
1137 | |
1090 | =item * non-repeating interval timer (interval > 0, reschedule_cb = 0) |
1138 | =item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1091 | |
1139 | |
1092 | In this mode the watcher will always be scheduled to time out at the next |
1140 | In this mode the watcher will always be scheduled to time out at the next |
1093 | C<at + N * interval> time (for some integer N) and then repeat, regardless |
1141 | C<at + N * interval> time (for some integer N, which can also be negative) |
1094 | of any time jumps. |
1142 | and then repeat, regardless of any time jumps. |
1095 | |
1143 | |
1096 | This can be used to create timers that do not drift with respect to system |
1144 | This can be used to create timers that do not drift with respect to system |
1097 | time: |
1145 | time: |
1098 | |
1146 | |
1099 | ev_periodic_set (&periodic, 0., 3600., 0); |
1147 | ev_periodic_set (&periodic, 0., 3600., 0); |
… | |
… | |
1105 | |
1153 | |
1106 | Another way to think about it (for the mathematically inclined) is that |
1154 | Another way to think about it (for the mathematically inclined) is that |
1107 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1155 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1108 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1156 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1109 | |
1157 | |
|
|
1158 | For numerical stability it is preferable that the C<at> value is near |
|
|
1159 | C<ev_now ()> (the current time), but there is no range requirement for |
|
|
1160 | this value. |
|
|
1161 | |
1110 | =item * manual reschedule mode (reschedule_cb = callback) |
1162 | =item * manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
1111 | |
1163 | |
1112 | In this mode the values for C<interval> and C<at> are both being |
1164 | In this mode the values for C<interval> and C<at> are both being |
1113 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1165 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1114 | reschedule callback will be called with the watcher as first, and the |
1166 | reschedule callback will be called with the watcher as first, and the |
1115 | current time as second argument. |
1167 | current time as second argument. |
1116 | |
1168 | |
1117 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1169 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1118 | ever, or make any event loop modifications>. If you need to stop it, |
1170 | ever, or make any event loop modifications>. If you need to stop it, |
1119 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1171 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1120 | starting a prepare watcher). |
1172 | starting an C<ev_prepare> watcher, which is legal). |
1121 | |
1173 | |
1122 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1174 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1123 | ev_tstamp now)>, e.g.: |
1175 | ev_tstamp now)>, e.g.: |
1124 | |
1176 | |
1125 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
1177 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
1148 | Simply stops and restarts the periodic watcher again. This is only useful |
1200 | Simply stops and restarts the periodic watcher again. This is only useful |
1149 | when you changed some parameters or the reschedule callback would return |
1201 | when you changed some parameters or the reschedule callback would return |
1150 | a different time than the last time it was called (e.g. in a crond like |
1202 | a different time than the last time it was called (e.g. in a crond like |
1151 | program when the crontabs have changed). |
1203 | program when the crontabs have changed). |
1152 | |
1204 | |
|
|
1205 | =item ev_tstamp offset [read-write] |
|
|
1206 | |
|
|
1207 | When repeating, this contains the offset value, otherwise this is the |
|
|
1208 | absolute point in time (the C<at> value passed to C<ev_periodic_set>). |
|
|
1209 | |
|
|
1210 | Can be modified any time, but changes only take effect when the periodic |
|
|
1211 | timer fires or C<ev_periodic_again> is being called. |
|
|
1212 | |
1153 | =item ev_tstamp interval [read-write] |
1213 | =item ev_tstamp interval [read-write] |
1154 | |
1214 | |
1155 | The current interval value. Can be modified any time, but changes only |
1215 | The current interval value. Can be modified any time, but changes only |
1156 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1216 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1157 | called. |
1217 | called. |
… | |
… | |
1159 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
1219 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
1160 | |
1220 | |
1161 | The current reschedule callback, or C<0>, if this functionality is |
1221 | The current reschedule callback, or C<0>, if this functionality is |
1162 | 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 |
1163 | the periodic timer fires or C<ev_periodic_again> is being called. |
1223 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
|
1224 | |
|
|
1225 | =item ev_tstamp at [read-only] |
|
|
1226 | |
|
|
1227 | When active, contains the absolute time that the watcher is supposed to |
|
|
1228 | trigger next. |
1164 | |
1229 | |
1165 | =back |
1230 | =back |
1166 | |
1231 | |
1167 | Example: Call a callback every hour, or, more precisely, whenever the |
1232 | Example: Call a callback every hour, or, more precisely, whenever the |
1168 | system clock is divisible by 3600. The callback invocation times have |
1233 | system clock is divisible by 3600. The callback invocation times have |
… | |
… | |
1210 | with the kernel (thus it coexists with your own signal handlers as long |
1275 | with the kernel (thus it coexists with your own signal handlers as long |
1211 | as you don't register any with libev). Similarly, when the last signal |
1276 | as you don't register any with libev). Similarly, when the last signal |
1212 | watcher for a signal is stopped libev will reset the signal handler to |
1277 | watcher for a signal is stopped libev will reset the signal handler to |
1213 | SIG_DFL (regardless of what it was set to before). |
1278 | SIG_DFL (regardless of what it was set to before). |
1214 | |
1279 | |
|
|
1280 | =head3 Watcher-Specific Functions and Data Members |
|
|
1281 | |
1215 | =over 4 |
1282 | =over 4 |
1216 | |
1283 | |
1217 | =item ev_signal_init (ev_signal *, callback, int signum) |
1284 | =item ev_signal_init (ev_signal *, callback, int signum) |
1218 | |
1285 | |
1219 | =item ev_signal_set (ev_signal *, int signum) |
1286 | =item ev_signal_set (ev_signal *, int signum) |
… | |
… | |
1230 | |
1297 | |
1231 | =head2 C<ev_child> - watch out for process status changes |
1298 | =head2 C<ev_child> - watch out for process status changes |
1232 | |
1299 | |
1233 | Child watchers trigger when your process receives a SIGCHLD in response to |
1300 | Child watchers trigger when your process receives a SIGCHLD in response to |
1234 | some child status changes (most typically when a child of yours dies). |
1301 | some child status changes (most typically when a child of yours dies). |
|
|
1302 | |
|
|
1303 | =head3 Watcher-Specific Functions and Data Members |
1235 | |
1304 | |
1236 | =over 4 |
1305 | =over 4 |
1237 | |
1306 | |
1238 | =item ev_child_init (ev_child *, callback, int pid) |
1307 | =item ev_child_init (ev_child *, callback, int pid) |
1239 | |
1308 | |
… | |
… | |
1307 | reader). Inotify will be used to give hints only and should not change the |
1376 | reader). Inotify will be used to give hints only and should not change the |
1308 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1377 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1309 | to fall back to regular polling again even with inotify, but changes are |
1378 | to fall back to regular polling again even with inotify, but changes are |
1310 | usually detected immediately, and if the file exists there will be no |
1379 | usually detected immediately, and if the file exists there will be no |
1311 | polling. |
1380 | polling. |
|
|
1381 | |
|
|
1382 | =head3 Watcher-Specific Functions and Data Members |
1312 | |
1383 | |
1313 | =over 4 |
1384 | =over 4 |
1314 | |
1385 | |
1315 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1386 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1316 | |
1387 | |
… | |
… | |
1399 | Apart from keeping your process non-blocking (which is a useful |
1470 | Apart from keeping your process non-blocking (which is a useful |
1400 | effect on its own sometimes), idle watchers are a good place to do |
1471 | effect on its own sometimes), idle watchers are a good place to do |
1401 | "pseudo-background processing", or delay processing stuff to after the |
1472 | "pseudo-background processing", or delay processing stuff to after the |
1402 | event loop has handled all outstanding events. |
1473 | event loop has handled all outstanding events. |
1403 | |
1474 | |
|
|
1475 | =head3 Watcher-Specific Functions and Data Members |
|
|
1476 | |
1404 | =over 4 |
1477 | =over 4 |
1405 | |
1478 | |
1406 | =item ev_idle_init (ev_signal *, callback) |
1479 | =item ev_idle_init (ev_signal *, callback) |
1407 | |
1480 | |
1408 | Initialises and configures the idle watcher - it has no parameters of any |
1481 | Initialises and configures the idle watcher - it has no parameters of any |
… | |
… | |
1465 | with priority higher than or equal to the event loop and one coroutine |
1538 | with priority higher than or equal to the event loop and one coroutine |
1466 | of lower priority, but only once, using idle watchers to keep the event |
1539 | of lower priority, but only once, using idle watchers to keep the event |
1467 | loop from blocking if lower-priority coroutines are active, thus mapping |
1540 | loop from blocking if lower-priority coroutines are active, thus mapping |
1468 | low-priority coroutines to idle/background tasks). |
1541 | low-priority coroutines to idle/background tasks). |
1469 | |
1542 | |
|
|
1543 | It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>) |
|
|
1544 | priority, to ensure that they are being run before any other watchers |
|
|
1545 | after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers, |
|
|
1546 | too) should not activate ("feed") events into libev. While libev fully |
|
|
1547 | supports this, they will be called before other C<ev_check> watchers did |
|
|
1548 | their job. As C<ev_check> watchers are often used to embed other event |
|
|
1549 | loops those other event loops might be in an unusable state until their |
|
|
1550 | C<ev_check> watcher ran (always remind yourself to coexist peacefully with |
|
|
1551 | others). |
|
|
1552 | |
|
|
1553 | =head3 Watcher-Specific Functions and Data Members |
|
|
1554 | |
1470 | =over 4 |
1555 | =over 4 |
1471 | |
1556 | |
1472 | =item ev_prepare_init (ev_prepare *, callback) |
1557 | =item ev_prepare_init (ev_prepare *, callback) |
1473 | |
1558 | |
1474 | =item ev_check_init (ev_check *, callback) |
1559 | =item ev_check_init (ev_check *, callback) |
… | |
… | |
1477 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1562 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1478 | macros, but using them is utterly, utterly and completely pointless. |
1563 | macros, but using them is utterly, utterly and completely pointless. |
1479 | |
1564 | |
1480 | =back |
1565 | =back |
1481 | |
1566 | |
1482 | Example: To include a library such as adns, you would add IO watchers |
1567 | There are a number of principal ways to embed other event loops or modules |
1483 | and a timeout watcher in a prepare handler, as required by libadns, and |
1568 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1569 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
|
|
1570 | use for an actually working example. Another Perl module named C<EV::Glib> |
|
|
1571 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
|
|
1572 | into the Glib event loop). |
|
|
1573 | |
|
|
1574 | Method 1: Add IO watchers and a timeout watcher in a prepare handler, |
1484 | in a check watcher, destroy them and call into libadns. What follows is |
1575 | and in a check watcher, destroy them and call into libadns. What follows |
1485 | pseudo-code only of course: |
1576 | is pseudo-code only of course. This requires you to either use a low |
|
|
1577 | priority for the check watcher or use C<ev_clear_pending> explicitly, as |
|
|
1578 | the callbacks for the IO/timeout watchers might not have been called yet. |
1486 | |
1579 | |
1487 | static ev_io iow [nfd]; |
1580 | static ev_io iow [nfd]; |
1488 | static ev_timer tw; |
1581 | static ev_timer tw; |
1489 | |
1582 | |
1490 | static void |
1583 | static void |
1491 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1584 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1492 | { |
1585 | { |
1493 | // set the relevant poll flags |
|
|
1494 | // could also call adns_processreadable etc. here |
|
|
1495 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1496 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1497 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1498 | } |
1586 | } |
1499 | |
1587 | |
1500 | // create io watchers for each fd and a timer before blocking |
1588 | // create io watchers for each fd and a timer before blocking |
1501 | static void |
1589 | static void |
1502 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1590 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
… | |
… | |
1508 | |
1596 | |
1509 | /* the callback is illegal, but won't be called as we stop during check */ |
1597 | /* the callback is illegal, but won't be called as we stop during check */ |
1510 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1598 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1511 | ev_timer_start (loop, &tw); |
1599 | ev_timer_start (loop, &tw); |
1512 | |
1600 | |
1513 | // create on ev_io per pollfd |
1601 | // create one ev_io per pollfd |
1514 | for (int i = 0; i < nfd; ++i) |
1602 | for (int i = 0; i < nfd; ++i) |
1515 | { |
1603 | { |
1516 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1604 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1517 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1605 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1518 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1606 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1519 | |
1607 | |
1520 | fds [i].revents = 0; |
1608 | fds [i].revents = 0; |
1521 | iow [i].data = fds + i; |
|
|
1522 | ev_io_start (loop, iow + i); |
1609 | ev_io_start (loop, iow + i); |
1523 | } |
1610 | } |
1524 | } |
1611 | } |
1525 | |
1612 | |
1526 | // stop all watchers after blocking |
1613 | // stop all watchers after blocking |
… | |
… | |
1528 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1615 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1529 | { |
1616 | { |
1530 | ev_timer_stop (loop, &tw); |
1617 | ev_timer_stop (loop, &tw); |
1531 | |
1618 | |
1532 | for (int i = 0; i < nfd; ++i) |
1619 | for (int i = 0; i < nfd; ++i) |
|
|
1620 | { |
|
|
1621 | // set the relevant poll flags |
|
|
1622 | // could also call adns_processreadable etc. here |
|
|
1623 | struct pollfd *fd = fds + i; |
|
|
1624 | int revents = ev_clear_pending (iow + i); |
|
|
1625 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1626 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1627 | |
|
|
1628 | // now stop the watcher |
1533 | ev_io_stop (loop, iow + i); |
1629 | ev_io_stop (loop, iow + i); |
|
|
1630 | } |
1534 | |
1631 | |
1535 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1632 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1633 | } |
|
|
1634 | |
|
|
1635 | Method 2: This would be just like method 1, but you run C<adns_afterpoll> |
|
|
1636 | in the prepare watcher and would dispose of the check watcher. |
|
|
1637 | |
|
|
1638 | Method 3: If the module to be embedded supports explicit event |
|
|
1639 | notification (adns does), you can also make use of the actual watcher |
|
|
1640 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1641 | |
|
|
1642 | static void |
|
|
1643 | timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1644 | { |
|
|
1645 | adns_state ads = (adns_state)w->data; |
|
|
1646 | update_now (EV_A); |
|
|
1647 | |
|
|
1648 | adns_processtimeouts (ads, &tv_now); |
|
|
1649 | } |
|
|
1650 | |
|
|
1651 | static void |
|
|
1652 | io_cb (EV_P_ ev_io *w, int revents) |
|
|
1653 | { |
|
|
1654 | adns_state ads = (adns_state)w->data; |
|
|
1655 | update_now (EV_A); |
|
|
1656 | |
|
|
1657 | if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1658 | if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1659 | } |
|
|
1660 | |
|
|
1661 | // do not ever call adns_afterpoll |
|
|
1662 | |
|
|
1663 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1664 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1665 | their poll function. The drawback with this solution is that the main |
|
|
1666 | loop is now no longer controllable by EV. The C<Glib::EV> module does |
|
|
1667 | this. |
|
|
1668 | |
|
|
1669 | static gint |
|
|
1670 | event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1671 | { |
|
|
1672 | int got_events = 0; |
|
|
1673 | |
|
|
1674 | for (n = 0; n < nfds; ++n) |
|
|
1675 | // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1676 | |
|
|
1677 | if (timeout >= 0) |
|
|
1678 | // create/start timer |
|
|
1679 | |
|
|
1680 | // poll |
|
|
1681 | ev_loop (EV_A_ 0); |
|
|
1682 | |
|
|
1683 | // stop timer again |
|
|
1684 | if (timeout >= 0) |
|
|
1685 | ev_timer_stop (EV_A_ &to); |
|
|
1686 | |
|
|
1687 | // stop io watchers again - their callbacks should have set |
|
|
1688 | for (n = 0; n < nfds; ++n) |
|
|
1689 | ev_io_stop (EV_A_ iow [n]); |
|
|
1690 | |
|
|
1691 | return got_events; |
1536 | } |
1692 | } |
1537 | |
1693 | |
1538 | |
1694 | |
1539 | =head2 C<ev_embed> - when one backend isn't enough... |
1695 | =head2 C<ev_embed> - when one backend isn't enough... |
1540 | |
1696 | |
… | |
… | |
1604 | ev_embed_start (loop_hi, &embed); |
1760 | ev_embed_start (loop_hi, &embed); |
1605 | } |
1761 | } |
1606 | else |
1762 | else |
1607 | loop_lo = loop_hi; |
1763 | loop_lo = loop_hi; |
1608 | |
1764 | |
|
|
1765 | =head3 Watcher-Specific Functions and Data Members |
|
|
1766 | |
1609 | =over 4 |
1767 | =over 4 |
1610 | |
1768 | |
1611 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1769 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1612 | |
1770 | |
1613 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
1771 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
… | |
… | |
1639 | event loop blocks next and before C<ev_check> watchers are being called, |
1797 | event loop blocks next and before C<ev_check> watchers are being called, |
1640 | and only in the child after the fork. If whoever good citizen calling |
1798 | and only in the child after the fork. If whoever good citizen calling |
1641 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1799 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1642 | handlers will be invoked, too, of course. |
1800 | handlers will be invoked, too, of course. |
1643 | |
1801 | |
|
|
1802 | =head3 Watcher-Specific Functions and Data Members |
|
|
1803 | |
1644 | =over 4 |
1804 | =over 4 |
1645 | |
1805 | |
1646 | =item ev_fork_init (ev_signal *, callback) |
1806 | =item ev_fork_init (ev_signal *, callback) |
1647 | |
1807 | |
1648 | Initialises and configures the fork watcher - it has no parameters of any |
1808 | Initialises and configures the fork watcher - it has no parameters of any |
… | |
… | |
1749 | This automatically includes F<ev.h> and puts all of its definitions (many |
1909 | This automatically includes F<ev.h> and puts all of its definitions (many |
1750 | of them macros) into the global namespace. All C++ specific things are |
1910 | of them macros) into the global namespace. All C++ specific things are |
1751 | put into the C<ev> namespace. It should support all the same embedding |
1911 | put into the C<ev> namespace. It should support all the same embedding |
1752 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
1912 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
1753 | |
1913 | |
1754 | Care has been taken to keep the overhead low. The only data member added |
1914 | Care has been taken to keep the overhead low. The only data member the C++ |
1755 | to the C-style watchers is the event loop the watcher is associated with |
1915 | classes add (compared to plain C-style watchers) is the event loop pointer |
1756 | (or no additional members at all if you disable C<EV_MULTIPLICITY> when |
1916 | that the watcher is associated with (or no additional members at all if |
1757 | embedding libev). |
1917 | you disable C<EV_MULTIPLICITY> when embedding libev). |
1758 | |
1918 | |
1759 | Currently, functions and static and non-static member functions can be |
1919 | Currently, functions, and static and non-static member functions can be |
1760 | used as callbacks. Other types should be easy to add as long as they only |
1920 | used as callbacks. Other types should be easy to add as long as they only |
1761 | need one additional pointer for context. If you need support for other |
1921 | need one additional pointer for context. If you need support for other |
1762 | types of functors please contact the author (preferably after implementing |
1922 | types of functors please contact the author (preferably after implementing |
1763 | it). |
1923 | it). |
1764 | |
1924 | |
… | |
… | |
1828 | |
1988 | |
1829 | myclass obj; |
1989 | myclass obj; |
1830 | ev::io iow; |
1990 | ev::io iow; |
1831 | iow.set <myclass, &myclass::io_cb> (&obj); |
1991 | iow.set <myclass, &myclass::io_cb> (&obj); |
1832 | |
1992 | |
1833 | =item w->set (void (*function)(watcher &w, int), void *data = 0) |
1993 | =item w->set<function> (void *data = 0) |
1834 | |
1994 | |
1835 | Also sets a callback, but uses a static method or plain function as |
1995 | Also sets a callback, but uses a static method or plain function as |
1836 | callback. The optional C<data> argument will be stored in the watcher's |
1996 | callback. The optional C<data> argument will be stored in the watcher's |
1837 | C<data> member and is free for you to use. |
1997 | C<data> member and is free for you to use. |
1838 | |
1998 | |
|
|
1999 | The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>. |
|
|
2000 | |
1839 | See the method-C<set> above for more details. |
2001 | See the method-C<set> above for more details. |
|
|
2002 | |
|
|
2003 | Example: |
|
|
2004 | |
|
|
2005 | static void io_cb (ev::io &w, int revents) { } |
|
|
2006 | iow.set <io_cb> (); |
1840 | |
2007 | |
1841 | =item w->set (struct ev_loop *) |
2008 | =item w->set (struct ev_loop *) |
1842 | |
2009 | |
1843 | Associates a different C<struct ev_loop> with this watcher. You can only |
2010 | Associates a different C<struct ev_loop> with this watcher. You can only |
1844 | do this when the watcher is inactive (and not pending either). |
2011 | do this when the watcher is inactive (and not pending either). |
… | |
… | |
1857 | |
2024 | |
1858 | =item w->stop () |
2025 | =item w->stop () |
1859 | |
2026 | |
1860 | Stops the watcher if it is active. Again, no C<loop> argument. |
2027 | Stops the watcher if it is active. Again, no C<loop> argument. |
1861 | |
2028 | |
1862 | =item w->again () C<ev::timer>, C<ev::periodic> only |
2029 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
1863 | |
2030 | |
1864 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
2031 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
1865 | C<ev_TYPE_again> function. |
2032 | C<ev_TYPE_again> function. |
1866 | |
2033 | |
1867 | =item w->sweep () C<ev::embed> only |
2034 | =item w->sweep () (C<ev::embed> only) |
1868 | |
2035 | |
1869 | Invokes C<ev_embed_sweep>. |
2036 | Invokes C<ev_embed_sweep>. |
1870 | |
2037 | |
1871 | =item w->update () C<ev::stat> only |
2038 | =item w->update () (C<ev::stat> only) |
1872 | |
2039 | |
1873 | Invokes C<ev_stat_stat>. |
2040 | Invokes C<ev_stat_stat>. |
1874 | |
2041 | |
1875 | =back |
2042 | =back |
1876 | |
2043 | |
… | |
… | |
1896 | } |
2063 | } |
1897 | |
2064 | |
1898 | |
2065 | |
1899 | =head1 MACRO MAGIC |
2066 | =head1 MACRO MAGIC |
1900 | |
2067 | |
1901 | Libev can be compiled with a variety of options, the most fundemantal is |
2068 | Libev can be compiled with a variety of options, the most fundamantal |
1902 | C<EV_MULTIPLICITY>. This option determines whether (most) functions and |
2069 | of which is C<EV_MULTIPLICITY>. This option determines whether (most) |
1903 | callbacks have an initial C<struct ev_loop *> argument. |
2070 | functions and callbacks have an initial C<struct ev_loop *> argument. |
1904 | |
2071 | |
1905 | To make it easier to write programs that cope with either variant, the |
2072 | To make it easier to write programs that cope with either variant, the |
1906 | following macros are defined: |
2073 | following macros are defined: |
1907 | |
2074 | |
1908 | =over 4 |
2075 | =over 4 |