… | |
… | |
545 | |
545 | |
546 | =item C<EV_CHILD> |
546 | =item C<EV_CHILD> |
547 | |
547 | |
548 | The pid specified in the C<ev_child> watcher has received a status change. |
548 | The pid specified in the C<ev_child> watcher has received a status change. |
549 | |
549 | |
|
|
550 | =item C<EV_STAT> |
|
|
551 | |
|
|
552 | The path specified in the C<ev_stat> watcher changed its attributes somehow. |
|
|
553 | |
550 | =item C<EV_IDLE> |
554 | =item C<EV_IDLE> |
551 | |
555 | |
552 | The C<ev_idle> watcher has determined that you have nothing better to do. |
556 | The C<ev_idle> watcher has determined that you have nothing better to do. |
553 | |
557 | |
554 | =item C<EV_PREPARE> |
558 | =item C<EV_PREPARE> |
… | |
… | |
689 | |
693 | |
690 | |
694 | |
691 | =head1 WATCHER TYPES |
695 | =head1 WATCHER TYPES |
692 | |
696 | |
693 | This section describes each watcher in detail, but will not repeat |
697 | This section describes each watcher in detail, but will not repeat |
694 | information given in the last section. |
698 | information given in the last section. Any initialisation/set macros, |
|
|
699 | functions and members specific to the watcher type are explained. |
|
|
700 | |
|
|
701 | Members are additionally marked with either I<[read-only]>, meaning that, |
|
|
702 | while the watcher is active, you can look at the member and expect some |
|
|
703 | sensible content, but you must not modify it (you can modify it while the |
|
|
704 | watcher is stopped to your hearts content), or I<[read-write]>, which |
|
|
705 | means you can expect it to have some sensible content while the watcher |
|
|
706 | is active, but you can also modify it. Modifying it may not do something |
|
|
707 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
708 | not crash or malfunction in any way. |
695 | |
709 | |
696 | |
710 | |
697 | =head2 C<ev_io> - is this file descriptor readable or writable? |
711 | =head2 C<ev_io> - is this file descriptor readable or writable? |
698 | |
712 | |
699 | I/O watchers check whether a file descriptor is readable or writable |
713 | I/O watchers check whether a file descriptor is readable or writable |
… | |
… | |
742 | |
756 | |
743 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
757 | 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 |
758 | 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. |
759 | C<EV_READ | EV_WRITE> to receive the given events. |
746 | |
760 | |
|
|
761 | =item int fd [read-only] |
|
|
762 | |
|
|
763 | The file descriptor being watched. |
|
|
764 | |
|
|
765 | =item int events [read-only] |
|
|
766 | |
|
|
767 | The events being watched. |
|
|
768 | |
747 | =back |
769 | =back |
748 | |
770 | |
749 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
771 | 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 |
772 | readable, but only once. Since it is likely line-buffered, you could |
751 | attempt to read a whole line in the callback: |
773 | attempt to read a whole line in the callback: |
… | |
… | |
814 | |
836 | |
815 | If the timer is repeating, either start it if necessary (with the repeat |
837 | If the timer is repeating, either start it if necessary (with the repeat |
816 | value), or reset the running timer to the repeat value. |
838 | value), or reset the running timer to the repeat value. |
817 | |
839 | |
818 | This sounds a bit complicated, but here is a useful and typical |
840 | 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 |
841 | 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 |
842 | 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 |
843 | 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 |
844 | 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 |
845 | 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 |
846 | 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. |
847 | socket, you can stop the timer, and again will automatically restart it if |
|
|
848 | need be. |
|
|
849 | |
|
|
850 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
|
|
851 | and only ever use the C<repeat> value: |
|
|
852 | |
|
|
853 | ev_timer_init (timer, callback, 0., 5.); |
|
|
854 | ev_timer_again (loop, timer); |
|
|
855 | ... |
|
|
856 | timer->again = 17.; |
|
|
857 | ev_timer_again (loop, timer); |
|
|
858 | ... |
|
|
859 | timer->again = 10.; |
|
|
860 | ev_timer_again (loop, timer); |
|
|
861 | |
|
|
862 | This is more efficient then stopping/starting the timer eahc time you want |
|
|
863 | to modify its timeout value. |
|
|
864 | |
|
|
865 | =item ev_tstamp repeat [read-write] |
|
|
866 | |
|
|
867 | The current C<repeat> value. Will be used each time the watcher times out |
|
|
868 | or C<ev_timer_again> is called and determines the next timeout (if any), |
|
|
869 | which is also when any modifications are taken into account. |
826 | |
870 | |
827 | =back |
871 | =back |
828 | |
872 | |
829 | Example: create a timer that fires after 60 seconds. |
873 | Example: create a timer that fires after 60 seconds. |
830 | |
874 | |
… | |
… | |
957 | Simply stops and restarts the periodic watcher again. This is only useful |
1001 | Simply stops and restarts the periodic watcher again. This is only useful |
958 | when you changed some parameters or the reschedule callback would return |
1002 | 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 |
1003 | a different time than the last time it was called (e.g. in a crond like |
960 | program when the crontabs have changed). |
1004 | program when the crontabs have changed). |
961 | |
1005 | |
|
|
1006 | =item ev_tstamp interval [read-write] |
|
|
1007 | |
|
|
1008 | The current interval value. Can be modified any time, but changes only |
|
|
1009 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
|
|
1010 | called. |
|
|
1011 | |
|
|
1012 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
|
|
1013 | |
|
|
1014 | The current reschedule callback, or C<0>, if this functionality is |
|
|
1015 | switched off. Can be changed any time, but changes only take effect when |
|
|
1016 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
|
1017 | |
962 | =back |
1018 | =back |
963 | |
1019 | |
964 | Example: call a callback every hour, or, more precisely, whenever the |
1020 | Example: call a callback every hour, or, more precisely, whenever the |
965 | system clock is divisible by 3600. The callback invocation times have |
1021 | system clock is divisible by 3600. The callback invocation times have |
966 | potentially a lot of jittering, but good long-term stability. |
1022 | potentially a lot of jittering, but good long-term stability. |
… | |
… | |
1016 | =item ev_signal_set (ev_signal *, int signum) |
1072 | =item ev_signal_set (ev_signal *, int signum) |
1017 | |
1073 | |
1018 | Configures the watcher to trigger on the given signal number (usually one |
1074 | Configures the watcher to trigger on the given signal number (usually one |
1019 | of the C<SIGxxx> constants). |
1075 | of the C<SIGxxx> constants). |
1020 | |
1076 | |
|
|
1077 | =item int signum [read-only] |
|
|
1078 | |
|
|
1079 | The signal the watcher watches out for. |
|
|
1080 | |
1021 | =back |
1081 | =back |
1022 | |
1082 | |
1023 | |
1083 | |
1024 | =head2 C<ev_child> - watch out for process status changes |
1084 | =head2 C<ev_child> - watch out for process status changes |
1025 | |
1085 | |
… | |
… | |
1037 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1097 | 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 |
1098 | 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 |
1099 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1040 | process causing the status change. |
1100 | process causing the status change. |
1041 | |
1101 | |
|
|
1102 | =item int pid [read-only] |
|
|
1103 | |
|
|
1104 | The process id this watcher watches out for, or C<0>, meaning any process id. |
|
|
1105 | |
|
|
1106 | =item int rpid [read-write] |
|
|
1107 | |
|
|
1108 | The process id that detected a status change. |
|
|
1109 | |
|
|
1110 | =item int rstatus [read-write] |
|
|
1111 | |
|
|
1112 | The process exit/trace status caused by C<rpid> (see your systems |
|
|
1113 | C<waitpid> and C<sys/wait.h> documentation for details). |
|
|
1114 | |
1042 | =back |
1115 | =back |
1043 | |
1116 | |
1044 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1117 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1045 | |
1118 | |
1046 | static void |
1119 | static void |
… | |
… | |
1050 | } |
1123 | } |
1051 | |
1124 | |
1052 | struct ev_signal signal_watcher; |
1125 | struct ev_signal signal_watcher; |
1053 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1126 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1054 | ev_signal_start (loop, &sigint_cb); |
1127 | ev_signal_start (loop, &sigint_cb); |
|
|
1128 | |
|
|
1129 | |
|
|
1130 | =head2 C<ev_stat> - did the file attributes just change? |
|
|
1131 | |
|
|
1132 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1133 | C<stat> regularly (or when the OS says it changed) and sees if it changed |
|
|
1134 | compared to the last time, invoking the callback if it did. |
|
|
1135 | |
|
|
1136 | The path does not need to exist: changing from "path exists" to "path does |
|
|
1137 | not exist" is a status change like any other. The condition "path does |
|
|
1138 | not exist" is signified by the C<st_nlink> field being zero (which is |
|
|
1139 | otherwise always forced to be at least one) and all the other fields of |
|
|
1140 | the stat buffer having unspecified contents. |
|
|
1141 | |
|
|
1142 | Since there is no standard to do this, the portable implementation simply |
|
|
1143 | calls C<stat (2)> regulalry on the path to see if it changed somehow. You |
|
|
1144 | can specify a recommended polling interval for this case. If you specify |
|
|
1145 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
|
|
1146 | unspecified default> value will be used (which you can expect to be around |
|
|
1147 | five seconds, although this might change dynamically). Libev will also |
|
|
1148 | impose a minimum interval which is currently around C<0.1>, but thats |
|
|
1149 | usually overkill. |
|
|
1150 | |
|
|
1151 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1152 | as even with OS-supported change notifications, this can be |
|
|
1153 | resource-intensive. |
|
|
1154 | |
|
|
1155 | At the time of this writing, no specific OS backends are implemented, but |
|
|
1156 | if demand increases, at least a kqueue and inotify backend will be added. |
|
|
1157 | |
|
|
1158 | =over 4 |
|
|
1159 | |
|
|
1160 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
|
|
1161 | |
|
|
1162 | =item ev_stat_set (ev_stat *, const char *path, ev_tstamp interval) |
|
|
1163 | |
|
|
1164 | Configures the watcher to wait for status changes of the given |
|
|
1165 | C<path>. The C<interval> is a hint on how quickly a change is expected to |
|
|
1166 | be detected and should normally be specified as C<0> to let libev choose |
|
|
1167 | a suitable value. The memory pointed to by C<path> must point to the same |
|
|
1168 | path for as long as the watcher is active. |
|
|
1169 | |
|
|
1170 | The callback will be receive C<EV_STAT> when a change was detected, |
|
|
1171 | relative to the attributes at the time the watcher was started (or the |
|
|
1172 | last change was detected). |
|
|
1173 | |
|
|
1174 | =item ev_stat_stat (ev_stat *) |
|
|
1175 | |
|
|
1176 | Updates the stat buffer immediately with new values. If you change the |
|
|
1177 | watched path in your callback, you could call this fucntion to avoid |
|
|
1178 | detecting this change (while introducing a race condition). Can also be |
|
|
1179 | useful simply to find out the new values. |
|
|
1180 | |
|
|
1181 | =item ev_statdata attr [read-only] |
|
|
1182 | |
|
|
1183 | The most-recently detected attributes of the file. Although the type is of |
|
|
1184 | C<ev_statdata>, this is usually the (or one of the) C<struct stat> types |
|
|
1185 | suitable for your system. If the C<st_nlink> member is C<0>, then there |
|
|
1186 | was some error while C<stat>ing the file. |
|
|
1187 | |
|
|
1188 | =item ev_statdata prev [read-only] |
|
|
1189 | |
|
|
1190 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1191 | C<prev> != C<attr>. |
|
|
1192 | |
|
|
1193 | =item ev_tstamp interval [read-only] |
|
|
1194 | |
|
|
1195 | The specified interval. |
|
|
1196 | |
|
|
1197 | =item const char *path [read-only] |
|
|
1198 | |
|
|
1199 | The filesystem path that is being watched. |
|
|
1200 | |
|
|
1201 | =back |
|
|
1202 | |
|
|
1203 | Example: Watch C</etc/passwd> for attribute changes. |
|
|
1204 | |
|
|
1205 | static void |
|
|
1206 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1207 | { |
|
|
1208 | /* /etc/passwd changed in some way */ |
|
|
1209 | if (w->attr.st_nlink) |
|
|
1210 | { |
|
|
1211 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1212 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1213 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1214 | } |
|
|
1215 | else |
|
|
1216 | /* you shalt not abuse printf for puts */ |
|
|
1217 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1218 | "if this is windows, they already arrived\n"); |
|
|
1219 | } |
|
|
1220 | |
|
|
1221 | ... |
|
|
1222 | ev_stat passwd; |
|
|
1223 | |
|
|
1224 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1225 | ev_stat_start (loop, &passwd); |
1055 | |
1226 | |
1056 | |
1227 | |
1057 | =head2 C<ev_idle> - when you've got nothing better to do... |
1228 | =head2 C<ev_idle> - when you've got nothing better to do... |
1058 | |
1229 | |
1059 | Idle watchers trigger events when there are no other events are pending |
1230 | Idle watchers trigger events when there are no other events are pending |
… | |
… | |
1292 | |
1463 | |
1293 | Make a single, non-blocking sweep over the embedded loop. This works |
1464 | Make a single, non-blocking sweep over the embedded loop. This works |
1294 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1465 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1295 | apropriate way for embedded loops. |
1466 | apropriate way for embedded loops. |
1296 | |
1467 | |
|
|
1468 | =item struct ev_loop *loop [read-only] |
|
|
1469 | |
|
|
1470 | The embedded event loop. |
|
|
1471 | |
1297 | =back |
1472 | =back |
1298 | |
1473 | |
1299 | |
1474 | |
1300 | =head1 OTHER FUNCTIONS |
1475 | =head1 OTHER FUNCTIONS |
1301 | |
1476 | |