… | |
… | |
48 | the beginning of 1970, details are complicated, don't ask). This type is |
48 | the beginning of 1970, details are complicated, don't ask). This type is |
49 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
49 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
50 | to the C<double> type in C, and when you need to do any calculations on |
50 | to the C<double> type in C, and when you need to do any calculations on |
51 | it, you should treat it as such. |
51 | it, you should treat it as such. |
52 | |
52 | |
53 | |
|
|
54 | =head1 GLOBAL FUNCTIONS |
53 | =head1 GLOBAL FUNCTIONS |
55 | |
54 | |
56 | These functions can be called anytime, even before initialising the |
55 | These functions can be called anytime, even before initialising the |
57 | library in any way. |
56 | library in any way. |
58 | |
57 | |
… | |
… | |
116 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
115 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
117 | recommended ones. |
116 | recommended ones. |
118 | |
117 | |
119 | See the description of C<ev_embed> watchers for more info. |
118 | See the description of C<ev_embed> watchers for more info. |
120 | |
119 | |
121 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
120 | =item ev_set_allocator (void *(*cb)(void *ptr, size_t size)) |
122 | |
121 | |
123 | Sets the allocation function to use (the prototype is similar to the |
122 | Sets the allocation function to use (the prototype and semantics are |
124 | realloc C function, the semantics are identical). It is used to allocate |
123 | identical to the realloc C function). It is used to allocate and free |
125 | and free memory (no surprises here). If it returns zero when memory |
124 | memory (no surprises here). If it returns zero when memory needs to be |
126 | needs to be allocated, the library might abort or take some potentially |
125 | allocated, the library might abort or take some potentially destructive |
127 | destructive action. The default is your system realloc function. |
126 | action. The default is your system realloc function. |
128 | |
127 | |
129 | You could override this function in high-availability programs to, say, |
128 | You could override this function in high-availability programs to, say, |
130 | free some memory if it cannot allocate memory, to use a special allocator, |
129 | free some memory if it cannot allocate memory, to use a special allocator, |
131 | or even to sleep a while and retry until some memory is available. |
130 | or even to sleep a while and retry until some memory is available. |
132 | |
131 | |
133 | Example: replace the libev allocator with one that waits a bit and then |
132 | Example: replace the libev allocator with one that waits a bit and then |
134 | retries: better than mine). |
133 | retries: better than mine). |
135 | |
134 | |
136 | static void * |
135 | static void * |
137 | persistent_realloc (void *ptr, long size) |
136 | persistent_realloc (void *ptr, size_t size) |
138 | { |
137 | { |
139 | for (;;) |
138 | for (;;) |
140 | { |
139 | { |
141 | void *newptr = realloc (ptr, size); |
140 | void *newptr = realloc (ptr, size); |
142 | |
141 | |
… | |
… | |
545 | |
544 | |
546 | =item C<EV_CHILD> |
545 | =item C<EV_CHILD> |
547 | |
546 | |
548 | The pid specified in the C<ev_child> watcher has received a status change. |
547 | The pid specified in the C<ev_child> watcher has received a status change. |
549 | |
548 | |
|
|
549 | =item C<EV_STAT> |
|
|
550 | |
|
|
551 | The path specified in the C<ev_stat> watcher changed its attributes somehow. |
|
|
552 | |
550 | =item C<EV_IDLE> |
553 | =item C<EV_IDLE> |
551 | |
554 | |
552 | The C<ev_idle> watcher has determined that you have nothing better to do. |
555 | The C<ev_idle> watcher has determined that you have nothing better to do. |
553 | |
556 | |
554 | =item C<EV_PREPARE> |
557 | =item C<EV_PREPARE> |
… | |
… | |
561 | received events. Callbacks of both watcher types can start and stop as |
564 | received events. Callbacks of both watcher types can start and stop as |
562 | many watchers as they want, and all of them will be taken into account |
565 | many watchers as they want, and all of them will be taken into account |
563 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
566 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
564 | C<ev_loop> from blocking). |
567 | C<ev_loop> from blocking). |
565 | |
568 | |
|
|
569 | =item C<EV_EMBED> |
|
|
570 | |
|
|
571 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
|
|
572 | |
|
|
573 | =item C<EV_FORK> |
|
|
574 | |
|
|
575 | The event loop has been resumed in the child process after fork (see |
|
|
576 | C<ev_fork>). |
|
|
577 | |
566 | =item C<EV_ERROR> |
578 | =item C<EV_ERROR> |
567 | |
579 | |
568 | An unspecified error has occured, the watcher has been stopped. This might |
580 | An unspecified error has occured, the watcher has been stopped. This might |
569 | happen because the watcher could not be properly started because libev |
581 | happen because the watcher could not be properly started because libev |
570 | ran out of memory, a file descriptor was found to be closed or any other |
582 | ran out of memory, a file descriptor was found to be closed or any other |
… | |
… | |
689 | |
701 | |
690 | |
702 | |
691 | =head1 WATCHER TYPES |
703 | =head1 WATCHER TYPES |
692 | |
704 | |
693 | This section describes each watcher in detail, but will not repeat |
705 | This section describes each watcher in detail, but will not repeat |
694 | information given in the last section. |
706 | information given in the last section. Any initialisation/set macros, |
|
|
707 | functions and members specific to the watcher type are explained. |
|
|
708 | |
|
|
709 | Members are additionally marked with either I<[read-only]>, meaning that, |
|
|
710 | while the watcher is active, you can look at the member and expect some |
|
|
711 | sensible content, but you must not modify it (you can modify it while the |
|
|
712 | watcher is stopped to your hearts content), or I<[read-write]>, which |
|
|
713 | means you can expect it to have some sensible content while the watcher |
|
|
714 | is active, but you can also modify it. Modifying it may not do something |
|
|
715 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
716 | not crash or malfunction in any way. |
695 | |
717 | |
696 | |
718 | |
697 | =head2 C<ev_io> - is this file descriptor readable or writable? |
719 | =head2 C<ev_io> - is this file descriptor readable or writable? |
698 | |
720 | |
699 | I/O watchers check whether a file descriptor is readable or writable |
721 | I/O watchers check whether a file descriptor is readable or writable |
… | |
… | |
742 | |
764 | |
743 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
765 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
744 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
766 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
745 | C<EV_READ | EV_WRITE> to receive the given events. |
767 | C<EV_READ | EV_WRITE> to receive the given events. |
746 | |
768 | |
|
|
769 | =item int fd [read-only] |
|
|
770 | |
|
|
771 | The file descriptor being watched. |
|
|
772 | |
|
|
773 | =item int events [read-only] |
|
|
774 | |
|
|
775 | The events being watched. |
|
|
776 | |
747 | =back |
777 | =back |
748 | |
778 | |
749 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
779 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
750 | readable, but only once. Since it is likely line-buffered, you could |
780 | readable, but only once. Since it is likely line-buffered, you could |
751 | attempt to read a whole line in the callback: |
781 | attempt to read a whole line in the callback: |
… | |
… | |
814 | |
844 | |
815 | If the timer is repeating, either start it if necessary (with the repeat |
845 | If the timer is repeating, either start it if necessary (with the repeat |
816 | value), or reset the running timer to the repeat value. |
846 | value), or reset the running timer to the repeat value. |
817 | |
847 | |
818 | This sounds a bit complicated, but here is a useful and typical |
848 | This sounds a bit complicated, but here is a useful and typical |
819 | example: Imagine you have a tcp connection and you want a so-called idle |
849 | example: Imagine you have a tcp connection and you want a so-called |
820 | timeout, that is, you want to be called when there have been, say, 60 |
850 | idle timeout, that is, you want to be called when there have been, |
821 | seconds of inactivity on the socket. The easiest way to do this is to |
851 | say, 60 seconds of inactivity on the socket. The easiest way to do |
822 | configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each |
852 | this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling |
823 | time you successfully read or write some data. If you go into an idle |
853 | C<ev_timer_again> each time you successfully read or write some data. If |
824 | state where you do not expect data to travel on the socket, you can stop |
854 | you go into an idle state where you do not expect data to travel on the |
825 | the timer, and again will automatically restart it if need be. |
855 | socket, you can stop the timer, and again will automatically restart it if |
|
|
856 | need be. |
|
|
857 | |
|
|
858 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
|
|
859 | and only ever use the C<repeat> value: |
|
|
860 | |
|
|
861 | ev_timer_init (timer, callback, 0., 5.); |
|
|
862 | ev_timer_again (loop, timer); |
|
|
863 | ... |
|
|
864 | timer->again = 17.; |
|
|
865 | ev_timer_again (loop, timer); |
|
|
866 | ... |
|
|
867 | timer->again = 10.; |
|
|
868 | ev_timer_again (loop, timer); |
|
|
869 | |
|
|
870 | This is more efficient then stopping/starting the timer eahc time you want |
|
|
871 | to modify its timeout value. |
|
|
872 | |
|
|
873 | =item ev_tstamp repeat [read-write] |
|
|
874 | |
|
|
875 | The current C<repeat> value. Will be used each time the watcher times out |
|
|
876 | or C<ev_timer_again> is called and determines the next timeout (if any), |
|
|
877 | which is also when any modifications are taken into account. |
826 | |
878 | |
827 | =back |
879 | =back |
828 | |
880 | |
829 | Example: create a timer that fires after 60 seconds. |
881 | Example: create a timer that fires after 60 seconds. |
830 | |
882 | |
… | |
… | |
957 | Simply stops and restarts the periodic watcher again. This is only useful |
1009 | Simply stops and restarts the periodic watcher again. This is only useful |
958 | when you changed some parameters or the reschedule callback would return |
1010 | when you changed some parameters or the reschedule callback would return |
959 | a different time than the last time it was called (e.g. in a crond like |
1011 | a different time than the last time it was called (e.g. in a crond like |
960 | program when the crontabs have changed). |
1012 | program when the crontabs have changed). |
961 | |
1013 | |
|
|
1014 | =item ev_tstamp interval [read-write] |
|
|
1015 | |
|
|
1016 | The current interval value. Can be modified any time, but changes only |
|
|
1017 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
|
|
1018 | called. |
|
|
1019 | |
|
|
1020 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
|
|
1021 | |
|
|
1022 | The current reschedule callback, or C<0>, if this functionality is |
|
|
1023 | switched off. Can be changed any time, but changes only take effect when |
|
|
1024 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
|
1025 | |
962 | =back |
1026 | =back |
963 | |
1027 | |
964 | Example: call a callback every hour, or, more precisely, whenever the |
1028 | Example: call a callback every hour, or, more precisely, whenever the |
965 | system clock is divisible by 3600. The callback invocation times have |
1029 | system clock is divisible by 3600. The callback invocation times have |
966 | potentially a lot of jittering, but good long-term stability. |
1030 | potentially a lot of jittering, but good long-term stability. |
… | |
… | |
1016 | =item ev_signal_set (ev_signal *, int signum) |
1080 | =item ev_signal_set (ev_signal *, int signum) |
1017 | |
1081 | |
1018 | Configures the watcher to trigger on the given signal number (usually one |
1082 | Configures the watcher to trigger on the given signal number (usually one |
1019 | of the C<SIGxxx> constants). |
1083 | of the C<SIGxxx> constants). |
1020 | |
1084 | |
|
|
1085 | =item int signum [read-only] |
|
|
1086 | |
|
|
1087 | The signal the watcher watches out for. |
|
|
1088 | |
1021 | =back |
1089 | =back |
1022 | |
1090 | |
1023 | |
1091 | |
1024 | =head2 C<ev_child> - watch out for process status changes |
1092 | =head2 C<ev_child> - watch out for process status changes |
1025 | |
1093 | |
… | |
… | |
1037 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1105 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1038 | the status word (use the macros from C<sys/wait.h> and see your systems |
1106 | the status word (use the macros from C<sys/wait.h> and see your systems |
1039 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1107 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1040 | process causing the status change. |
1108 | process causing the status change. |
1041 | |
1109 | |
|
|
1110 | =item int pid [read-only] |
|
|
1111 | |
|
|
1112 | The process id this watcher watches out for, or C<0>, meaning any process id. |
|
|
1113 | |
|
|
1114 | =item int rpid [read-write] |
|
|
1115 | |
|
|
1116 | The process id that detected a status change. |
|
|
1117 | |
|
|
1118 | =item int rstatus [read-write] |
|
|
1119 | |
|
|
1120 | The process exit/trace status caused by C<rpid> (see your systems |
|
|
1121 | C<waitpid> and C<sys/wait.h> documentation for details). |
|
|
1122 | |
1042 | =back |
1123 | =back |
1043 | |
1124 | |
1044 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1125 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1045 | |
1126 | |
1046 | static void |
1127 | static void |
… | |
… | |
1050 | } |
1131 | } |
1051 | |
1132 | |
1052 | struct ev_signal signal_watcher; |
1133 | struct ev_signal signal_watcher; |
1053 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1134 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1054 | ev_signal_start (loop, &sigint_cb); |
1135 | ev_signal_start (loop, &sigint_cb); |
|
|
1136 | |
|
|
1137 | |
|
|
1138 | =head2 C<ev_stat> - did the file attributes just change? |
|
|
1139 | |
|
|
1140 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1141 | C<stat> regularly (or when the OS says it changed) and sees if it changed |
|
|
1142 | compared to the last time, invoking the callback if it did. |
|
|
1143 | |
|
|
1144 | The path does not need to exist: changing from "path exists" to "path does |
|
|
1145 | not exist" is a status change like any other. The condition "path does |
|
|
1146 | not exist" is signified by the C<st_nlink> field being zero (which is |
|
|
1147 | otherwise always forced to be at least one) and all the other fields of |
|
|
1148 | the stat buffer having unspecified contents. |
|
|
1149 | |
|
|
1150 | Since there is no standard to do this, the portable implementation simply |
|
|
1151 | calls C<stat (2)> regulalry on the path to see if it changed somehow. You |
|
|
1152 | can specify a recommended polling interval for this case. If you specify |
|
|
1153 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
|
|
1154 | unspecified default> value will be used (which you can expect to be around |
|
|
1155 | five seconds, although this might change dynamically). Libev will also |
|
|
1156 | impose a minimum interval which is currently around C<0.1>, but thats |
|
|
1157 | usually overkill. |
|
|
1158 | |
|
|
1159 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1160 | as even with OS-supported change notifications, this can be |
|
|
1161 | resource-intensive. |
|
|
1162 | |
|
|
1163 | At the time of this writing, no specific OS backends are implemented, but |
|
|
1164 | if demand increases, at least a kqueue and inotify backend will be added. |
|
|
1165 | |
|
|
1166 | =over 4 |
|
|
1167 | |
|
|
1168 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
|
|
1169 | |
|
|
1170 | =item ev_stat_set (ev_stat *, const char *path, ev_tstamp interval) |
|
|
1171 | |
|
|
1172 | Configures the watcher to wait for status changes of the given |
|
|
1173 | C<path>. The C<interval> is a hint on how quickly a change is expected to |
|
|
1174 | be detected and should normally be specified as C<0> to let libev choose |
|
|
1175 | a suitable value. The memory pointed to by C<path> must point to the same |
|
|
1176 | path for as long as the watcher is active. |
|
|
1177 | |
|
|
1178 | The callback will be receive C<EV_STAT> when a change was detected, |
|
|
1179 | relative to the attributes at the time the watcher was started (or the |
|
|
1180 | last change was detected). |
|
|
1181 | |
|
|
1182 | =item ev_stat_stat (ev_stat *) |
|
|
1183 | |
|
|
1184 | Updates the stat buffer immediately with new values. If you change the |
|
|
1185 | watched path in your callback, you could call this fucntion to avoid |
|
|
1186 | detecting this change (while introducing a race condition). Can also be |
|
|
1187 | useful simply to find out the new values. |
|
|
1188 | |
|
|
1189 | =item ev_statdata attr [read-only] |
|
|
1190 | |
|
|
1191 | The most-recently detected attributes of the file. Although the type is of |
|
|
1192 | C<ev_statdata>, this is usually the (or one of the) C<struct stat> types |
|
|
1193 | suitable for your system. If the C<st_nlink> member is C<0>, then there |
|
|
1194 | was some error while C<stat>ing the file. |
|
|
1195 | |
|
|
1196 | =item ev_statdata prev [read-only] |
|
|
1197 | |
|
|
1198 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1199 | C<prev> != C<attr>. |
|
|
1200 | |
|
|
1201 | =item ev_tstamp interval [read-only] |
|
|
1202 | |
|
|
1203 | The specified interval. |
|
|
1204 | |
|
|
1205 | =item const char *path [read-only] |
|
|
1206 | |
|
|
1207 | The filesystem path that is being watched. |
|
|
1208 | |
|
|
1209 | =back |
|
|
1210 | |
|
|
1211 | Example: Watch C</etc/passwd> for attribute changes. |
|
|
1212 | |
|
|
1213 | static void |
|
|
1214 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1215 | { |
|
|
1216 | /* /etc/passwd changed in some way */ |
|
|
1217 | if (w->attr.st_nlink) |
|
|
1218 | { |
|
|
1219 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1220 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1221 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1222 | } |
|
|
1223 | else |
|
|
1224 | /* you shalt not abuse printf for puts */ |
|
|
1225 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1226 | "if this is windows, they already arrived\n"); |
|
|
1227 | } |
|
|
1228 | |
|
|
1229 | ... |
|
|
1230 | ev_stat passwd; |
|
|
1231 | |
|
|
1232 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1233 | ev_stat_start (loop, &passwd); |
1055 | |
1234 | |
1056 | |
1235 | |
1057 | =head2 C<ev_idle> - when you've got nothing better to do... |
1236 | =head2 C<ev_idle> - when you've got nothing better to do... |
1058 | |
1237 | |
1059 | Idle watchers trigger events when there are no other events are pending |
1238 | Idle watchers trigger events when there are no other events are pending |
… | |
… | |
1160 | |
1339 | |
1161 | static void |
1340 | static void |
1162 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1341 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1163 | { |
1342 | { |
1164 | // set the relevant poll flags |
1343 | // set the relevant poll flags |
|
|
1344 | // could also call adns_processreadable etc. here |
1165 | struct pollfd *fd = (struct pollfd *)w->data; |
1345 | struct pollfd *fd = (struct pollfd *)w->data; |
1166 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1346 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1167 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1347 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1168 | } |
1348 | } |
1169 | |
1349 | |
… | |
… | |
1291 | |
1471 | |
1292 | Make a single, non-blocking sweep over the embedded loop. This works |
1472 | Make a single, non-blocking sweep over the embedded loop. This works |
1293 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1473 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1294 | apropriate way for embedded loops. |
1474 | apropriate way for embedded loops. |
1295 | |
1475 | |
|
|
1476 | =item struct ev_loop *loop [read-only] |
|
|
1477 | |
|
|
1478 | The embedded event loop. |
|
|
1479 | |
|
|
1480 | =back |
|
|
1481 | |
|
|
1482 | |
|
|
1483 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
|
|
1484 | |
|
|
1485 | Fork watchers are called when a C<fork ()> was detected (usually because |
|
|
1486 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1487 | C<ev_default_fork> or C<ev_loop_fork>). The invocation is done before the |
|
|
1488 | event loop blocks next and before C<ev_check> watchers are being called, |
|
|
1489 | and only in the child after the fork. If whoever good citizen calling |
|
|
1490 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
|
|
1491 | handlers will be invoked, too, of course. |
|
|
1492 | |
|
|
1493 | =over 4 |
|
|
1494 | |
|
|
1495 | =item ev_fork_init (ev_signal *, callback) |
|
|
1496 | |
|
|
1497 | Initialises and configures the fork watcher - it has no parameters of any |
|
|
1498 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
|
|
1499 | believe me. |
|
|
1500 | |
1296 | =back |
1501 | =back |
1297 | |
1502 | |
1298 | |
1503 | |
1299 | =head1 OTHER FUNCTIONS |
1504 | =head1 OTHER FUNCTIONS |
1300 | |
1505 | |
… | |
… | |
1462 | |
1667 | |
1463 | =item w->sweep () C<ev::embed> only |
1668 | =item w->sweep () C<ev::embed> only |
1464 | |
1669 | |
1465 | Invokes C<ev_embed_sweep>. |
1670 | Invokes C<ev_embed_sweep>. |
1466 | |
1671 | |
|
|
1672 | =item w->update () C<ev::stat> only |
|
|
1673 | |
|
|
1674 | Invokes C<ev_stat_stat>. |
|
|
1675 | |
1467 | =back |
1676 | =back |
1468 | |
1677 | |
1469 | =back |
1678 | =back |
1470 | |
1679 | |
1471 | Example: Define a class with an IO and idle watcher, start one of them in |
1680 | Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1483 | : io (this, &myclass::io_cb), |
1692 | : io (this, &myclass::io_cb), |
1484 | idle (this, &myclass::idle_cb) |
1693 | idle (this, &myclass::idle_cb) |
1485 | { |
1694 | { |
1486 | io.start (fd, ev::READ); |
1695 | io.start (fd, ev::READ); |
1487 | } |
1696 | } |
|
|
1697 | |
|
|
1698 | |
|
|
1699 | =head1 MACRO MAGIC |
|
|
1700 | |
|
|
1701 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1702 | C<EV_MULTIPLICITY>. This option determines wether (most) functions and |
|
|
1703 | callbacks have an initial C<struct ev_loop *> argument. |
|
|
1704 | |
|
|
1705 | To make it easier to write programs that cope with either variant, the |
|
|
1706 | following macros are defined: |
|
|
1707 | |
|
|
1708 | =over 4 |
|
|
1709 | |
|
|
1710 | =item C<EV_A>, C<EV_A_> |
|
|
1711 | |
|
|
1712 | This provides the loop I<argument> for functions, if one is required ("ev |
|
|
1713 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
|
|
1714 | C<EV_A_> is used when other arguments are following. Example: |
|
|
1715 | |
|
|
1716 | ev_unref (EV_A); |
|
|
1717 | ev_timer_add (EV_A_ watcher); |
|
|
1718 | ev_loop (EV_A_ 0); |
|
|
1719 | |
|
|
1720 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
|
|
1721 | which is often provided by the following macro. |
|
|
1722 | |
|
|
1723 | =item C<EV_P>, C<EV_P_> |
|
|
1724 | |
|
|
1725 | This provides the loop I<parameter> for functions, if one is required ("ev |
|
|
1726 | loop parameter"). The C<EV_P> form is used when this is the sole parameter, |
|
|
1727 | C<EV_P_> is used when other parameters are following. Example: |
|
|
1728 | |
|
|
1729 | // this is how ev_unref is being declared |
|
|
1730 | static void ev_unref (EV_P); |
|
|
1731 | |
|
|
1732 | // this is how you can declare your typical callback |
|
|
1733 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1734 | |
|
|
1735 | It declares a parameter C<loop> of type C<struct ev_loop *>, quite |
|
|
1736 | suitable for use with C<EV_A>. |
|
|
1737 | |
|
|
1738 | =item C<EV_DEFAULT>, C<EV_DEFAULT_> |
|
|
1739 | |
|
|
1740 | Similar to the other two macros, this gives you the value of the default |
|
|
1741 | loop, if multiple loops are supported ("ev loop default"). |
|
|
1742 | |
|
|
1743 | =back |
|
|
1744 | |
|
|
1745 | Example: Declare and initialise a check watcher, working regardless of |
|
|
1746 | wether multiple loops are supported or not. |
|
|
1747 | |
|
|
1748 | static void |
|
|
1749 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1750 | { |
|
|
1751 | ev_check_stop (EV_A_ w); |
|
|
1752 | } |
|
|
1753 | |
|
|
1754 | ev_check check; |
|
|
1755 | ev_check_init (&check, check_cb); |
|
|
1756 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1757 | ev_loop (EV_DEFAULT_ 0); |
|
|
1758 | |
1488 | |
1759 | |
1489 | =head1 EMBEDDING |
1760 | =head1 EMBEDDING |
1490 | |
1761 | |
1491 | Libev can (and often is) directly embedded into host |
1762 | Libev can (and often is) directly embedded into host |
1492 | applications. Examples of applications that embed it include the Deliantra |
1763 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1699 | will have the C<struct ev_loop *> as first argument, and you can create |
1970 | will have the C<struct ev_loop *> as first argument, and you can create |
1700 | additional independent event loops. Otherwise there will be no support |
1971 | additional independent event loops. Otherwise there will be no support |
1701 | for multiple event loops and there is no first event loop pointer |
1972 | for multiple event loops and there is no first event loop pointer |
1702 | argument. Instead, all functions act on the single default loop. |
1973 | argument. Instead, all functions act on the single default loop. |
1703 | |
1974 | |
1704 | =item EV_PERIODICS |
1975 | =item EV_PERIODIC_ENABLE |
1705 | |
1976 | |
1706 | If undefined or defined to be C<1>, then periodic timers are supported, |
1977 | If undefined or defined to be C<1>, then periodic timers are supported. If |
1707 | otherwise not. This saves a few kb of code. |
1978 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
1979 | code. |
|
|
1980 | |
|
|
1981 | =item EV_EMBED_ENABLE |
|
|
1982 | |
|
|
1983 | If undefined or defined to be C<1>, then embed watchers are supported. If |
|
|
1984 | defined to be C<0>, then they are not. |
|
|
1985 | |
|
|
1986 | =item EV_STAT_ENABLE |
|
|
1987 | |
|
|
1988 | If undefined or defined to be C<1>, then stat watchers are supported. If |
|
|
1989 | defined to be C<0>, then they are not. |
|
|
1990 | |
|
|
1991 | =item EV_FORK_ENABLE |
|
|
1992 | |
|
|
1993 | If undefined or defined to be C<1>, then fork watchers are supported. If |
|
|
1994 | defined to be C<0>, then they are not. |
|
|
1995 | |
|
|
1996 | =item EV_MINIMAL |
|
|
1997 | |
|
|
1998 | If you need to shave off some kilobytes of code at the expense of some |
|
|
1999 | speed, define this symbol to C<1>. Currently only used for gcc to override |
|
|
2000 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2001 | |
|
|
2002 | =item EV_PID_HASHSIZE |
|
|
2003 | |
|
|
2004 | C<ev_child> watchers use a small hash table to distribute workload by |
|
|
2005 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
|
|
2006 | than enough. If you need to manage thousands of children you might want to |
|
|
2007 | increase this value. |
1708 | |
2008 | |
1709 | =item EV_COMMON |
2009 | =item EV_COMMON |
1710 | |
2010 | |
1711 | By default, all watchers have a C<void *data> member. By redefining |
2011 | By default, all watchers have a C<void *data> member. By redefining |
1712 | this macro to a something else you can include more and other types of |
2012 | this macro to a something else you can include more and other types of |
… | |
… | |
1755 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2055 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
1756 | |
2056 | |
1757 | #include "ev_cpp.h" |
2057 | #include "ev_cpp.h" |
1758 | #include "ev.c" |
2058 | #include "ev.c" |
1759 | |
2059 | |
|
|
2060 | |
|
|
2061 | =head1 COMPLEXITIES |
|
|
2062 | |
|
|
2063 | In this section the complexities of (many of) the algorithms used inside |
|
|
2064 | libev will be explained. For complexity discussions about backends see the |
|
|
2065 | documentation for C<ev_default_init>. |
|
|
2066 | |
|
|
2067 | =over 4 |
|
|
2068 | |
|
|
2069 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
|
|
2070 | |
|
|
2071 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
|
|
2072 | |
|
|
2073 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
|
|
2074 | |
|
|
2075 | =item Stopping check/prepare/idle watchers: O(1) |
|
|
2076 | |
|
|
2077 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16)) |
|
|
2078 | |
|
|
2079 | =item Finding the next timer per loop iteration: O(1) |
|
|
2080 | |
|
|
2081 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
|
|
2082 | |
|
|
2083 | =item Activating one watcher: O(1) |
|
|
2084 | |
|
|
2085 | =back |
|
|
2086 | |
|
|
2087 | |
1760 | =head1 AUTHOR |
2088 | =head1 AUTHOR |
1761 | |
2089 | |
1762 | Marc Lehmann <libev@schmorp.de>. |
2090 | Marc Lehmann <libev@schmorp.de>. |
1763 | |
2091 | |