… | |
… | |
53 | The newest version of this document is also available as a html-formatted |
53 | The newest version of this document is also available as a html-formatted |
54 | web page you might find easier to navigate when reading it for the first |
54 | web page you might find easier to navigate when reading it for the first |
55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
56 | |
56 | |
57 | Libev is an event loop: you register interest in certain events (such as a |
57 | Libev is an event loop: you register interest in certain events (such as a |
58 | file descriptor being readable or a timeout occuring), and it will manage |
58 | file descriptor being readable or a timeout occurring), and it will manage |
59 | these event sources and provide your program with events. |
59 | these event sources and provide your program with events. |
60 | |
60 | |
61 | To do this, it must take more or less complete control over your process |
61 | To do this, it must take more or less complete control over your process |
62 | (or thread) by executing the I<event loop> handler, and will then |
62 | (or thread) by executing the I<event loop> handler, and will then |
63 | communicate events via a callback mechanism. |
63 | communicate events via a callback mechanism. |
… | |
… | |
98 | Libev represents time as a single floating point number, representing the |
98 | Libev represents time as a single floating point number, representing the |
99 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
99 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
100 | the beginning of 1970, details are complicated, don't ask). This type is |
100 | the beginning of 1970, details are complicated, don't ask). This type is |
101 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
101 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
102 | to the C<double> type in C, and when you need to do any calculations on |
102 | to the C<double> type in C, and when you need to do any calculations on |
103 | it, you should treat it as such. |
103 | it, you should treat it as some floatingpoint value. Unlike the name |
|
|
104 | component C<stamp> might indicate, it is also used for time differences |
|
|
105 | throughout libev. |
104 | |
106 | |
105 | =head1 GLOBAL FUNCTIONS |
107 | =head1 GLOBAL FUNCTIONS |
106 | |
108 | |
107 | These functions can be called anytime, even before initialising the |
109 | These functions can be called anytime, even before initialising the |
108 | library in any way. |
110 | library in any way. |
… | |
… | |
117 | |
119 | |
118 | =item int ev_version_major () |
120 | =item int ev_version_major () |
119 | |
121 | |
120 | =item int ev_version_minor () |
122 | =item int ev_version_minor () |
121 | |
123 | |
122 | You can find out the major and minor version numbers of the library |
124 | 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 |
125 | 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 |
126 | 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 |
127 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
126 | version of the library your program was compiled against. |
128 | version of the library your program was compiled against. |
127 | |
129 | |
|
|
130 | These version numbers refer to the ABI version of the library, not the |
|
|
131 | release version. |
|
|
132 | |
128 | Usually, it's a good idea to terminate if the major versions mismatch, |
133 | Usually, it's a good idea to terminate if the major versions mismatch, |
129 | as this indicates an incompatible change. Minor versions are usually |
134 | as this indicates an incompatible change. Minor versions are usually |
130 | compatible to older versions, so a larger minor version alone is usually |
135 | compatible to older versions, so a larger minor version alone is usually |
131 | not a problem. |
136 | not a problem. |
132 | |
137 | |
133 | Example: Make sure we haven't accidentally been linked against the wrong |
138 | Example: Make sure we haven't accidentally been linked against the wrong |
134 | version. |
139 | version. |
… | |
… | |
326 | |
331 | |
327 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
332 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
328 | |
333 | |
329 | Kqueue deserves special mention, as at the time of this writing, it |
334 | Kqueue deserves special mention, as at the time of this writing, it |
330 | was broken on all BSDs except NetBSD (usually it doesn't work with |
335 | was broken on all BSDs except NetBSD (usually it doesn't work with |
331 | anything but sockets and pipes, except on Darwin, where of course its |
336 | anything but sockets and pipes, except on Darwin, where of course it's |
332 | completely useless). For this reason its not being "autodetected" |
337 | completely useless). For this reason it's not being "autodetected" |
333 | unless you explicitly specify it explicitly in the flags (i.e. using |
338 | unless you explicitly specify it explicitly in the flags (i.e. using |
334 | C<EVBACKEND_KQUEUE>). |
339 | C<EVBACKEND_KQUEUE>). |
335 | |
340 | |
336 | It scales in the same way as the epoll backend, but the interface to the |
341 | It scales in the same way as the epoll backend, but the interface to the |
337 | kernel is more efficient (which says nothing about its actual speed, of |
342 | kernel is more efficient (which says nothing about its actual speed, of |
… | |
… | |
399 | Destroys the default loop again (frees all memory and kernel state |
404 | Destroys the default loop again (frees all memory and kernel state |
400 | etc.). None of the active event watchers will be stopped in the normal |
405 | etc.). None of the active event watchers will be stopped in the normal |
401 | sense, so e.g. C<ev_is_active> might still return true. It is your |
406 | sense, so e.g. C<ev_is_active> might still return true. It is your |
402 | responsibility to either stop all watchers cleanly yoursef I<before> |
407 | responsibility to either stop all watchers cleanly yoursef I<before> |
403 | calling this function, or cope with the fact afterwards (which is usually |
408 | calling this function, or cope with the fact afterwards (which is usually |
404 | the easiest thing, youc na just ignore the watchers and/or C<free ()> them |
409 | the easiest thing, you can just ignore the watchers and/or C<free ()> them |
405 | for example). |
410 | for example). |
|
|
411 | |
|
|
412 | Note that certain global state, such as signal state, will not be freed by |
|
|
413 | this function, and related watchers (such as signal and child watchers) |
|
|
414 | would need to be stopped manually. |
|
|
415 | |
|
|
416 | In general it is not advisable to call this function except in the |
|
|
417 | rare occasion where you really need to free e.g. the signal handling |
|
|
418 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
419 | C<ev_loop_new> and C<ev_loop_destroy>). |
406 | |
420 | |
407 | =item ev_loop_destroy (loop) |
421 | =item ev_loop_destroy (loop) |
408 | |
422 | |
409 | Like C<ev_default_destroy>, but destroys an event loop created by an |
423 | Like C<ev_default_destroy>, but destroys an event loop created by an |
410 | earlier call to C<ev_loop_new>. |
424 | earlier call to C<ev_loop_new>. |
… | |
… | |
455 | |
469 | |
456 | Returns the current "event loop time", which is the time the event loop |
470 | Returns the current "event loop time", which is the time the event loop |
457 | received events and started processing them. This timestamp does not |
471 | received events and started processing them. This timestamp does not |
458 | change as long as callbacks are being processed, and this is also the base |
472 | change as long as callbacks are being processed, and this is also the base |
459 | time used for relative timers. You can treat it as the timestamp of the |
473 | time used for relative timers. You can treat it as the timestamp of the |
460 | event occuring (or more correctly, libev finding out about it). |
474 | event occurring (or more correctly, libev finding out about it). |
461 | |
475 | |
462 | =item ev_loop (loop, int flags) |
476 | =item ev_loop (loop, int flags) |
463 | |
477 | |
464 | Finally, this is it, the event handler. This function usually is called |
478 | Finally, this is it, the event handler. This function usually is called |
465 | after you initialised all your watchers and you want to start handling |
479 | after you initialised all your watchers and you want to start handling |
… | |
… | |
486 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
500 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
487 | usually a better approach for this kind of thing. |
501 | usually a better approach for this kind of thing. |
488 | |
502 | |
489 | Here are the gory details of what C<ev_loop> does: |
503 | Here are the gory details of what C<ev_loop> does: |
490 | |
504 | |
|
|
505 | - Before the first iteration, call any pending watchers. |
491 | * If there are no active watchers (reference count is zero), return. |
506 | * If there are no active watchers (reference count is zero), return. |
492 | - Queue prepare watchers and then call all outstanding watchers. |
507 | - Queue all prepare watchers and then call all outstanding watchers. |
493 | - If we have been forked, recreate the kernel state. |
508 | - If we have been forked, recreate the kernel state. |
494 | - Update the kernel state with all outstanding changes. |
509 | - Update the kernel state with all outstanding changes. |
495 | - Update the "event loop time". |
510 | - Update the "event loop time". |
496 | - Calculate for how long to block. |
511 | - Calculate for how long to block. |
497 | - Block the process, waiting for any events. |
512 | - Block the process, waiting for any events. |
… | |
… | |
907 | play around with an Xlib connection), then you have to seperately re-test |
922 | play around with an Xlib connection), then you have to seperately re-test |
908 | whether a file descriptor is really ready with a known-to-be good interface |
923 | whether a file descriptor is really ready with a known-to-be good interface |
909 | such as poll (fortunately in our Xlib example, Xlib already does this on |
924 | such as poll (fortunately in our Xlib example, Xlib already does this on |
910 | its own, so its quite safe to use). |
925 | its own, so its quite safe to use). |
911 | |
926 | |
|
|
927 | =head3 The special problem of disappearing file descriptors |
|
|
928 | |
|
|
929 | Some backends (e.g kqueue, epoll) need to be told about closing a file |
|
|
930 | descriptor (either by calling C<close> explicitly or by any other means, |
|
|
931 | such as C<dup>). The reason is that you register interest in some file |
|
|
932 | descriptor, but when it goes away, the operating system will silently drop |
|
|
933 | this interest. If another file descriptor with the same number then is |
|
|
934 | registered with libev, there is no efficient way to see that this is, in |
|
|
935 | fact, a different file descriptor. |
|
|
936 | |
|
|
937 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
938 | the following policy: Each time C<ev_io_set> is being called, libev |
|
|
939 | will assume that this is potentially a new file descriptor, otherwise |
|
|
940 | it is assumed that the file descriptor stays the same. That means that |
|
|
941 | you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the |
|
|
942 | descriptor even if the file descriptor number itself did not change. |
|
|
943 | |
|
|
944 | This is how one would do it normally anyway, the important point is that |
|
|
945 | the libev application should not optimise around libev but should leave |
|
|
946 | optimisations to libev. |
|
|
947 | |
|
|
948 | |
|
|
949 | =head3 Watcher-Specific Functions |
|
|
950 | |
912 | =over 4 |
951 | =over 4 |
913 | |
952 | |
914 | =item ev_io_init (ev_io *, callback, int fd, int events) |
953 | =item ev_io_init (ev_io *, callback, int fd, int events) |
915 | |
954 | |
916 | =item ev_io_set (ev_io *, int fd, int events) |
955 | =item ev_io_set (ev_io *, int fd, int events) |
… | |
… | |
968 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
1007 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
969 | |
1008 | |
970 | The callback is guarenteed to be invoked only when its timeout has passed, |
1009 | The callback is guarenteed to be invoked only when its timeout has passed, |
971 | but if multiple timers become ready during the same loop iteration then |
1010 | but if multiple timers become ready during the same loop iteration then |
972 | order of execution is undefined. |
1011 | order of execution is undefined. |
|
|
1012 | |
|
|
1013 | =head3 Watcher-Specific Functions and Data Members |
973 | |
1014 | |
974 | =over 4 |
1015 | =over 4 |
975 | |
1016 | |
976 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
1017 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
977 | |
1018 | |
… | |
… | |
1073 | but on wallclock time (absolute time). You can tell a periodic watcher |
1114 | but on wallclock time (absolute time). You can tell a periodic watcher |
1074 | to trigger "at" some specific point in time. For example, if you tell a |
1115 | to trigger "at" some specific point in time. For example, if you tell a |
1075 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1116 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1076 | + 10.>) and then reset your system clock to the last year, then it will |
1117 | + 10.>) and then reset your system clock to the last year, then it will |
1077 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1118 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1078 | roughly 10 seconds later and of course not if you reset your system time |
1119 | roughly 10 seconds later). |
1079 | again). |
|
|
1080 | |
1120 | |
1081 | They can also be used to implement vastly more complex timers, such as |
1121 | They can also be used to implement vastly more complex timers, such as |
1082 | triggering an event on eahc midnight, local time. |
1122 | triggering an event on each midnight, local time or other, complicated, |
|
|
1123 | rules. |
1083 | |
1124 | |
1084 | As with timers, the callback is guarenteed to be invoked only when the |
1125 | As with timers, the callback is guarenteed to be invoked only when the |
1085 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1126 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1086 | during the same loop iteration then order of execution is undefined. |
1127 | during the same loop iteration then order of execution is undefined. |
1087 | |
1128 | |
|
|
1129 | =head3 Watcher-Specific Functions and Data Members |
|
|
1130 | |
1088 | =over 4 |
1131 | =over 4 |
1089 | |
1132 | |
1090 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1133 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1091 | |
1134 | |
1092 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
1135 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
… | |
… | |
1094 | Lots of arguments, lets sort it out... There are basically three modes of |
1137 | Lots of arguments, lets sort it out... There are basically three modes of |
1095 | operation, and we will explain them from simplest to complex: |
1138 | operation, and we will explain them from simplest to complex: |
1096 | |
1139 | |
1097 | =over 4 |
1140 | =over 4 |
1098 | |
1141 | |
1099 | =item * absolute timer (interval = reschedule_cb = 0) |
1142 | =item * absolute timer (at = time, interval = reschedule_cb = 0) |
1100 | |
1143 | |
1101 | In this configuration the watcher triggers an event at the wallclock time |
1144 | In this configuration the watcher triggers an event at the wallclock time |
1102 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1145 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1103 | that is, if it is to be run at January 1st 2011 then it will run when the |
1146 | that is, if it is to be run at January 1st 2011 then it will run when the |
1104 | system time reaches or surpasses this time. |
1147 | system time reaches or surpasses this time. |
1105 | |
1148 | |
1106 | =item * non-repeating interval timer (interval > 0, reschedule_cb = 0) |
1149 | =item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1107 | |
1150 | |
1108 | In this mode the watcher will always be scheduled to time out at the next |
1151 | In this mode the watcher will always be scheduled to time out at the next |
1109 | C<at + N * interval> time (for some integer N) and then repeat, regardless |
1152 | C<at + N * interval> time (for some integer N, which can also be negative) |
1110 | of any time jumps. |
1153 | and then repeat, regardless of any time jumps. |
1111 | |
1154 | |
1112 | This can be used to create timers that do not drift with respect to system |
1155 | This can be used to create timers that do not drift with respect to system |
1113 | time: |
1156 | time: |
1114 | |
1157 | |
1115 | ev_periodic_set (&periodic, 0., 3600., 0); |
1158 | ev_periodic_set (&periodic, 0., 3600., 0); |
… | |
… | |
1121 | |
1164 | |
1122 | Another way to think about it (for the mathematically inclined) is that |
1165 | Another way to think about it (for the mathematically inclined) is that |
1123 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1166 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1124 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1167 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1125 | |
1168 | |
|
|
1169 | For numerical stability it is preferable that the C<at> value is near |
|
|
1170 | C<ev_now ()> (the current time), but there is no range requirement for |
|
|
1171 | this value. |
|
|
1172 | |
1126 | =item * manual reschedule mode (reschedule_cb = callback) |
1173 | =item * manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
1127 | |
1174 | |
1128 | In this mode the values for C<interval> and C<at> are both being |
1175 | In this mode the values for C<interval> and C<at> are both being |
1129 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1176 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1130 | reschedule callback will be called with the watcher as first, and the |
1177 | reschedule callback will be called with the watcher as first, and the |
1131 | current time as second argument. |
1178 | current time as second argument. |
1132 | |
1179 | |
1133 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1180 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1134 | ever, or make any event loop modifications>. If you need to stop it, |
1181 | ever, or make any event loop modifications>. If you need to stop it, |
1135 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1182 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1136 | starting a prepare watcher). |
1183 | starting an C<ev_prepare> watcher, which is legal). |
1137 | |
1184 | |
1138 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1185 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1139 | ev_tstamp now)>, e.g.: |
1186 | ev_tstamp now)>, e.g.: |
1140 | |
1187 | |
1141 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
1188 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
1164 | Simply stops and restarts the periodic watcher again. This is only useful |
1211 | Simply stops and restarts the periodic watcher again. This is only useful |
1165 | when you changed some parameters or the reschedule callback would return |
1212 | when you changed some parameters or the reschedule callback would return |
1166 | a different time than the last time it was called (e.g. in a crond like |
1213 | a different time than the last time it was called (e.g. in a crond like |
1167 | program when the crontabs have changed). |
1214 | program when the crontabs have changed). |
1168 | |
1215 | |
|
|
1216 | =item ev_tstamp offset [read-write] |
|
|
1217 | |
|
|
1218 | When repeating, this contains the offset value, otherwise this is the |
|
|
1219 | absolute point in time (the C<at> value passed to C<ev_periodic_set>). |
|
|
1220 | |
|
|
1221 | Can be modified any time, but changes only take effect when the periodic |
|
|
1222 | timer fires or C<ev_periodic_again> is being called. |
|
|
1223 | |
1169 | =item ev_tstamp interval [read-write] |
1224 | =item ev_tstamp interval [read-write] |
1170 | |
1225 | |
1171 | The current interval value. Can be modified any time, but changes only |
1226 | The current interval value. Can be modified any time, but changes only |
1172 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1227 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1173 | called. |
1228 | called. |
… | |
… | |
1175 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
1230 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
1176 | |
1231 | |
1177 | The current reschedule callback, or C<0>, if this functionality is |
1232 | The current reschedule callback, or C<0>, if this functionality is |
1178 | switched off. Can be changed any time, but changes only take effect when |
1233 | switched off. Can be changed any time, but changes only take effect when |
1179 | the periodic timer fires or C<ev_periodic_again> is being called. |
1234 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
|
1235 | |
|
|
1236 | =item ev_tstamp at [read-only] |
|
|
1237 | |
|
|
1238 | When active, contains the absolute time that the watcher is supposed to |
|
|
1239 | trigger next. |
1180 | |
1240 | |
1181 | =back |
1241 | =back |
1182 | |
1242 | |
1183 | Example: Call a callback every hour, or, more precisely, whenever the |
1243 | Example: Call a callback every hour, or, more precisely, whenever the |
1184 | system clock is divisible by 3600. The callback invocation times have |
1244 | system clock is divisible by 3600. The callback invocation times have |
… | |
… | |
1226 | with the kernel (thus it coexists with your own signal handlers as long |
1286 | with the kernel (thus it coexists with your own signal handlers as long |
1227 | as you don't register any with libev). Similarly, when the last signal |
1287 | as you don't register any with libev). Similarly, when the last signal |
1228 | watcher for a signal is stopped libev will reset the signal handler to |
1288 | watcher for a signal is stopped libev will reset the signal handler to |
1229 | SIG_DFL (regardless of what it was set to before). |
1289 | SIG_DFL (regardless of what it was set to before). |
1230 | |
1290 | |
|
|
1291 | =head3 Watcher-Specific Functions and Data Members |
|
|
1292 | |
1231 | =over 4 |
1293 | =over 4 |
1232 | |
1294 | |
1233 | =item ev_signal_init (ev_signal *, callback, int signum) |
1295 | =item ev_signal_init (ev_signal *, callback, int signum) |
1234 | |
1296 | |
1235 | =item ev_signal_set (ev_signal *, int signum) |
1297 | =item ev_signal_set (ev_signal *, int signum) |
… | |
… | |
1246 | |
1308 | |
1247 | =head2 C<ev_child> - watch out for process status changes |
1309 | =head2 C<ev_child> - watch out for process status changes |
1248 | |
1310 | |
1249 | Child watchers trigger when your process receives a SIGCHLD in response to |
1311 | Child watchers trigger when your process receives a SIGCHLD in response to |
1250 | some child status changes (most typically when a child of yours dies). |
1312 | some child status changes (most typically when a child of yours dies). |
|
|
1313 | |
|
|
1314 | =head3 Watcher-Specific Functions and Data Members |
1251 | |
1315 | |
1252 | =over 4 |
1316 | =over 4 |
1253 | |
1317 | |
1254 | =item ev_child_init (ev_child *, callback, int pid) |
1318 | =item ev_child_init (ev_child *, callback, int pid) |
1255 | |
1319 | |
… | |
… | |
1323 | reader). Inotify will be used to give hints only and should not change the |
1387 | reader). Inotify will be used to give hints only and should not change the |
1324 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1388 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1325 | to fall back to regular polling again even with inotify, but changes are |
1389 | to fall back to regular polling again even with inotify, but changes are |
1326 | usually detected immediately, and if the file exists there will be no |
1390 | usually detected immediately, and if the file exists there will be no |
1327 | polling. |
1391 | polling. |
|
|
1392 | |
|
|
1393 | =head3 Watcher-Specific Functions and Data Members |
1328 | |
1394 | |
1329 | =over 4 |
1395 | =over 4 |
1330 | |
1396 | |
1331 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1397 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1332 | |
1398 | |
… | |
… | |
1415 | Apart from keeping your process non-blocking (which is a useful |
1481 | Apart from keeping your process non-blocking (which is a useful |
1416 | effect on its own sometimes), idle watchers are a good place to do |
1482 | effect on its own sometimes), idle watchers are a good place to do |
1417 | "pseudo-background processing", or delay processing stuff to after the |
1483 | "pseudo-background processing", or delay processing stuff to after the |
1418 | event loop has handled all outstanding events. |
1484 | event loop has handled all outstanding events. |
1419 | |
1485 | |
|
|
1486 | =head3 Watcher-Specific Functions and Data Members |
|
|
1487 | |
1420 | =over 4 |
1488 | =over 4 |
1421 | |
1489 | |
1422 | =item ev_idle_init (ev_signal *, callback) |
1490 | =item ev_idle_init (ev_signal *, callback) |
1423 | |
1491 | |
1424 | Initialises and configures the idle watcher - it has no parameters of any |
1492 | Initialises and configures the idle watcher - it has no parameters of any |
… | |
… | |
1480 | are ready to run (it's actually more complicated: it only runs coroutines |
1548 | are ready to run (it's actually more complicated: it only runs coroutines |
1481 | with priority higher than or equal to the event loop and one coroutine |
1549 | with priority higher than or equal to the event loop and one coroutine |
1482 | of lower priority, but only once, using idle watchers to keep the event |
1550 | of lower priority, but only once, using idle watchers to keep the event |
1483 | loop from blocking if lower-priority coroutines are active, thus mapping |
1551 | loop from blocking if lower-priority coroutines are active, thus mapping |
1484 | low-priority coroutines to idle/background tasks). |
1552 | low-priority coroutines to idle/background tasks). |
|
|
1553 | |
|
|
1554 | It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>) |
|
|
1555 | priority, to ensure that they are being run before any other watchers |
|
|
1556 | after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers, |
|
|
1557 | too) should not activate ("feed") events into libev. While libev fully |
|
|
1558 | supports this, they will be called before other C<ev_check> watchers did |
|
|
1559 | their job. As C<ev_check> watchers are often used to embed other event |
|
|
1560 | loops those other event loops might be in an unusable state until their |
|
|
1561 | C<ev_check> watcher ran (always remind yourself to coexist peacefully with |
|
|
1562 | others). |
|
|
1563 | |
|
|
1564 | =head3 Watcher-Specific Functions and Data Members |
1485 | |
1565 | |
1486 | =over 4 |
1566 | =over 4 |
1487 | |
1567 | |
1488 | =item ev_prepare_init (ev_prepare *, callback) |
1568 | =item ev_prepare_init (ev_prepare *, callback) |
1489 | |
1569 | |
… | |
… | |
1691 | ev_embed_start (loop_hi, &embed); |
1771 | ev_embed_start (loop_hi, &embed); |
1692 | } |
1772 | } |
1693 | else |
1773 | else |
1694 | loop_lo = loop_hi; |
1774 | loop_lo = loop_hi; |
1695 | |
1775 | |
|
|
1776 | =head3 Watcher-Specific Functions and Data Members |
|
|
1777 | |
1696 | =over 4 |
1778 | =over 4 |
1697 | |
1779 | |
1698 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1780 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1699 | |
1781 | |
1700 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
1782 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
… | |
… | |
1709 | |
1791 | |
1710 | Make a single, non-blocking sweep over the embedded loop. This works |
1792 | Make a single, non-blocking sweep over the embedded loop. This works |
1711 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1793 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1712 | apropriate way for embedded loops. |
1794 | apropriate way for embedded loops. |
1713 | |
1795 | |
1714 | =item struct ev_loop *loop [read-only] |
1796 | =item struct ev_loop *other [read-only] |
1715 | |
1797 | |
1716 | The embedded event loop. |
1798 | The embedded event loop. |
1717 | |
1799 | |
1718 | =back |
1800 | =back |
1719 | |
1801 | |
… | |
… | |
1726 | event loop blocks next and before C<ev_check> watchers are being called, |
1808 | event loop blocks next and before C<ev_check> watchers are being called, |
1727 | and only in the child after the fork. If whoever good citizen calling |
1809 | and only in the child after the fork. If whoever good citizen calling |
1728 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1810 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1729 | handlers will be invoked, too, of course. |
1811 | handlers will be invoked, too, of course. |
1730 | |
1812 | |
|
|
1813 | =head3 Watcher-Specific Functions and Data Members |
|
|
1814 | |
1731 | =over 4 |
1815 | =over 4 |
1732 | |
1816 | |
1733 | =item ev_fork_init (ev_signal *, callback) |
1817 | =item ev_fork_init (ev_signal *, callback) |
1734 | |
1818 | |
1735 | Initialises and configures the fork watcher - it has no parameters of any |
1819 | Initialises and configures the fork watcher - it has no parameters of any |
… | |
… | |
1951 | |
2035 | |
1952 | =item w->stop () |
2036 | =item w->stop () |
1953 | |
2037 | |
1954 | Stops the watcher if it is active. Again, no C<loop> argument. |
2038 | Stops the watcher if it is active. Again, no C<loop> argument. |
1955 | |
2039 | |
1956 | =item w->again () C<ev::timer>, C<ev::periodic> only |
2040 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
1957 | |
2041 | |
1958 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
2042 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
1959 | C<ev_TYPE_again> function. |
2043 | C<ev_TYPE_again> function. |
1960 | |
2044 | |
1961 | =item w->sweep () C<ev::embed> only |
2045 | =item w->sweep () (C<ev::embed> only) |
1962 | |
2046 | |
1963 | Invokes C<ev_embed_sweep>. |
2047 | Invokes C<ev_embed_sweep>. |
1964 | |
2048 | |
1965 | =item w->update () C<ev::stat> only |
2049 | =item w->update () (C<ev::stat> only) |
1966 | |
2050 | |
1967 | Invokes C<ev_stat_stat>. |
2051 | Invokes C<ev_stat_stat>. |
1968 | |
2052 | |
1969 | =back |
2053 | =back |
1970 | |
2054 | |
… | |
… | |
1990 | } |
2074 | } |
1991 | |
2075 | |
1992 | |
2076 | |
1993 | =head1 MACRO MAGIC |
2077 | =head1 MACRO MAGIC |
1994 | |
2078 | |
1995 | Libev can be compiled with a variety of options, the most fundemantal is |
2079 | Libev can be compiled with a variety of options, the most fundamantal |
1996 | C<EV_MULTIPLICITY>. This option determines whether (most) functions and |
2080 | of which is C<EV_MULTIPLICITY>. This option determines whether (most) |
1997 | callbacks have an initial C<struct ev_loop *> argument. |
2081 | functions and callbacks have an initial C<struct ev_loop *> argument. |
1998 | |
2082 | |
1999 | To make it easier to write programs that cope with either variant, the |
2083 | To make it easier to write programs that cope with either variant, the |
2000 | following macros are defined: |
2084 | following macros are defined: |
2001 | |
2085 | |
2002 | =over 4 |
2086 | =over 4 |
… | |
… | |
2056 | Libev can (and often is) directly embedded into host |
2140 | Libev can (and often is) directly embedded into host |
2057 | applications. Examples of applications that embed it include the Deliantra |
2141 | applications. Examples of applications that embed it include the Deliantra |
2058 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
2142 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
2059 | and rxvt-unicode. |
2143 | and rxvt-unicode. |
2060 | |
2144 | |
2061 | The goal is to enable you to just copy the neecssary files into your |
2145 | The goal is to enable you to just copy the necessary files into your |
2062 | source directory without having to change even a single line in them, so |
2146 | source directory without having to change even a single line in them, so |
2063 | you can easily upgrade by simply copying (or having a checked-out copy of |
2147 | you can easily upgrade by simply copying (or having a checked-out copy of |
2064 | libev somewhere in your source tree). |
2148 | libev somewhere in your source tree). |
2065 | |
2149 | |
2066 | =head2 FILESETS |
2150 | =head2 FILESETS |
… | |
… | |
2156 | |
2240 | |
2157 | If defined to be C<1>, libev will try to detect the availability of the |
2241 | If defined to be C<1>, libev will try to detect the availability of the |
2158 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2242 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2159 | of the monotonic clock option will be attempted. If you enable this, you |
2243 | of the monotonic clock option will be attempted. If you enable this, you |
2160 | usually have to link against librt or something similar. Enabling it when |
2244 | usually have to link against librt or something similar. Enabling it when |
2161 | the functionality isn't available is safe, though, althoguh you have |
2245 | the functionality isn't available is safe, though, although you have |
2162 | to make sure you link against any libraries where the C<clock_gettime> |
2246 | to make sure you link against any libraries where the C<clock_gettime> |
2163 | function is hiding in (often F<-lrt>). |
2247 | function is hiding in (often F<-lrt>). |
2164 | |
2248 | |
2165 | =item EV_USE_REALTIME |
2249 | =item EV_USE_REALTIME |
2166 | |
2250 | |
2167 | If defined to be C<1>, libev will try to detect the availability of the |
2251 | If defined to be C<1>, libev will try to detect the availability of the |
2168 | realtime clock option at compiletime (and assume its availability at |
2252 | realtime clock option at compiletime (and assume its availability at |
2169 | runtime if successful). Otherwise no use of the realtime clock option will |
2253 | runtime if successful). Otherwise no use of the realtime clock option will |
2170 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
2254 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
2171 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See tzhe note about libraries |
2255 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See the |
2172 | in the description of C<EV_USE_MONOTONIC>, though. |
2256 | note about libraries in the description of C<EV_USE_MONOTONIC>, though. |
2173 | |
2257 | |
2174 | =item EV_USE_SELECT |
2258 | =item EV_USE_SELECT |
2175 | |
2259 | |
2176 | If undefined or defined to be C<1>, libev will compile in support for the |
2260 | If undefined or defined to be C<1>, libev will compile in support for the |
2177 | C<select>(2) backend. No attempt at autodetection will be done: if no |
2261 | C<select>(2) backend. No attempt at autodetection will be done: if no |
… | |
… | |
2356 | |
2440 | |
2357 | =item ev_set_cb (ev, cb) |
2441 | =item ev_set_cb (ev, cb) |
2358 | |
2442 | |
2359 | Can be used to change the callback member declaration in each watcher, |
2443 | Can be used to change the callback member declaration in each watcher, |
2360 | and the way callbacks are invoked and set. Must expand to a struct member |
2444 | and the way callbacks are invoked and set. Must expand to a struct member |
2361 | definition and a statement, respectively. See the F<ev.v> header file for |
2445 | definition and a statement, respectively. See the F<ev.h> header file for |
2362 | their default definitions. One possible use for overriding these is to |
2446 | their default definitions. One possible use for overriding these is to |
2363 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
2447 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
2364 | method calls instead of plain function calls in C++. |
2448 | method calls instead of plain function calls in C++. |
|
|
2449 | |
|
|
2450 | =head2 EXPORTED API SYMBOLS |
|
|
2451 | |
|
|
2452 | If you need to re-export the API (e.g. via a dll) and you need a list of |
|
|
2453 | exported symbols, you can use the provided F<Symbol.*> files which list |
|
|
2454 | all public symbols, one per line: |
|
|
2455 | |
|
|
2456 | Symbols.ev for libev proper |
|
|
2457 | Symbols.event for the libevent emulation |
|
|
2458 | |
|
|
2459 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2460 | multiple versions of libev linked together (which is obviously bad in |
|
|
2461 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2462 | |
|
|
2463 | A sed command like this will create wrapper C<#define>'s that you need to |
|
|
2464 | include before including F<ev.h>: |
|
|
2465 | |
|
|
2466 | <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2467 | |
|
|
2468 | This would create a file F<wrap.h> which essentially looks like this: |
|
|
2469 | |
|
|
2470 | #define ev_backend myprefix_ev_backend |
|
|
2471 | #define ev_check_start myprefix_ev_check_start |
|
|
2472 | #define ev_check_stop myprefix_ev_check_stop |
|
|
2473 | ... |
2365 | |
2474 | |
2366 | =head2 EXAMPLES |
2475 | =head2 EXAMPLES |
2367 | |
2476 | |
2368 | For a real-world example of a program the includes libev |
2477 | For a real-world example of a program the includes libev |
2369 | verbatim, you can have a look at the EV perl module |
2478 | verbatim, you can have a look at the EV perl module |