… | |
… | |
127 | .\} |
127 | .\} |
128 | .rm #[ #] #H #V #F C |
128 | .rm #[ #] #H #V #F C |
129 | .\" ======================================================================== |
129 | .\" ======================================================================== |
130 | .\" |
130 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
137 | .Vb 1 |
… | |
… | |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
685 | .ie n .IP """EV_CHILD""" 4 |
685 | .ie n .IP """EV_CHILD""" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
687 | .IX Item "EV_CHILD" |
687 | .IX Item "EV_CHILD" |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
689 | .ie n .IP """EV_STAT""" 4 |
|
|
690 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
691 | .IX Item "EV_STAT" |
|
|
692 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
689 | .ie n .IP """EV_IDLE""" 4 |
693 | .ie n .IP """EV_IDLE""" 4 |
690 | .el .IP "\f(CWEV_IDLE\fR" 4 |
694 | .el .IP "\f(CWEV_IDLE\fR" 4 |
691 | .IX Item "EV_IDLE" |
695 | .IX Item "EV_IDLE" |
692 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
696 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
693 | .ie n .IP """EV_PREPARE""" 4 |
697 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
821 | More interesting and less C\-conformant ways of catsing your callback type |
825 | More interesting and less C\-conformant ways of catsing your callback type |
822 | have been omitted.... |
826 | have been omitted.... |
823 | .SH "WATCHER TYPES" |
827 | .SH "WATCHER TYPES" |
824 | .IX Header "WATCHER TYPES" |
828 | .IX Header "WATCHER TYPES" |
825 | This section describes each watcher in detail, but will not repeat |
829 | This section describes each watcher in detail, but will not repeat |
826 | information given in the last section. |
830 | information given in the last section. Any initialisation/set macros, |
|
|
831 | functions and members specific to the watcher type are explained. |
|
|
832 | .PP |
|
|
833 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
834 | while the watcher is active, you can look at the member and expect some |
|
|
835 | sensible content, but you must not modify it (you can modify it while the |
|
|
836 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
837 | means you can expect it to have some sensible content while the watcher |
|
|
838 | is active, but you can also modify it. Modifying it may not do something |
|
|
839 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
840 | not crash or malfunction in any way. |
827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
841 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
828 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
842 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
829 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
843 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
830 | I/O watchers check whether a file descriptor is readable or writable |
844 | I/O watchers check whether a file descriptor is readable or writable |
831 | in each iteration of the event loop, or, more precisely, when reading |
845 | in each iteration of the event loop, or, more precisely, when reading |
… | |
… | |
871 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
885 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
872 | .PD |
886 | .PD |
873 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
887 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
874 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
888 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
875 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
889 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
|
|
890 | .IP "int fd [read\-only]" 4 |
|
|
891 | .IX Item "int fd [read-only]" |
|
|
892 | The file descriptor being watched. |
|
|
893 | .IP "int events [read\-only]" 4 |
|
|
894 | .IX Item "int events [read-only]" |
|
|
895 | The events being watched. |
876 | .PP |
896 | .PP |
877 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
897 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
878 | readable, but only once. Since it is likely line\-buffered, you could |
898 | readable, but only once. Since it is likely line\-buffered, you could |
879 | attempt to read a whole line in the callback: |
899 | attempt to read a whole line in the callback: |
880 | .PP |
900 | .PP |
… | |
… | |
945 | .Sp |
965 | .Sp |
946 | If the timer is repeating, either start it if necessary (with the repeat |
966 | If the timer is repeating, either start it if necessary (with the repeat |
947 | value), or reset the running timer to the repeat value. |
967 | value), or reset the running timer to the repeat value. |
948 | .Sp |
968 | .Sp |
949 | This sounds a bit complicated, but here is a useful and typical |
969 | This sounds a bit complicated, but here is a useful and typical |
950 | example: Imagine you have a tcp connection and you want a so-called idle |
970 | example: Imagine you have a tcp connection and you want a so-called |
951 | timeout, that is, you want to be called when there have been, say, 60 |
971 | idle timeout, that is, you want to be called when there have been, |
952 | seconds of inactivity on the socket. The easiest way to do this is to |
972 | say, 60 seconds of inactivity on the socket. The easiest way to do |
953 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
973 | this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling |
954 | time you successfully read or write some data. If you go into an idle |
974 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
955 | state where you do not expect data to travel on the socket, you can stop |
975 | you go into an idle state where you do not expect data to travel on the |
956 | the timer, and again will automatically restart it if need be. |
976 | socket, you can stop the timer, and again will automatically restart it if |
|
|
977 | need be. |
|
|
978 | .Sp |
|
|
979 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
|
|
980 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
|
|
981 | .Sp |
|
|
982 | .Vb 8 |
|
|
983 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
984 | \& ev_timer_again (loop, timer); |
|
|
985 | \& ... |
|
|
986 | \& timer->again = 17.; |
|
|
987 | \& ev_timer_again (loop, timer); |
|
|
988 | \& ... |
|
|
989 | \& timer->again = 10.; |
|
|
990 | \& ev_timer_again (loop, timer); |
|
|
991 | .Ve |
|
|
992 | .Sp |
|
|
993 | This is more efficient then stopping/starting the timer eahc time you want |
|
|
994 | to modify its timeout value. |
|
|
995 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
996 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
997 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
998 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
999 | which is also when any modifications are taken into account. |
957 | .PP |
1000 | .PP |
958 | Example: create a timer that fires after 60 seconds. |
1001 | Example: create a timer that fires after 60 seconds. |
959 | .PP |
1002 | .PP |
960 | .Vb 5 |
1003 | .Vb 5 |
961 | \& static void |
1004 | \& static void |
… | |
… | |
1093 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1136 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1094 | Simply stops and restarts the periodic watcher again. This is only useful |
1137 | Simply stops and restarts the periodic watcher again. This is only useful |
1095 | when you changed some parameters or the reschedule callback would return |
1138 | when you changed some parameters or the reschedule callback would return |
1096 | a different time than the last time it was called (e.g. in a crond like |
1139 | a different time than the last time it was called (e.g. in a crond like |
1097 | program when the crontabs have changed). |
1140 | program when the crontabs have changed). |
|
|
1141 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1142 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1143 | The current interval value. Can be modified any time, but changes only |
|
|
1144 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1145 | called. |
|
|
1146 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1147 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1148 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1149 | switched off. Can be changed any time, but changes only take effect when |
|
|
1150 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1098 | .PP |
1151 | .PP |
1099 | Example: call a callback every hour, or, more precisely, whenever the |
1152 | Example: call a callback every hour, or, more precisely, whenever the |
1100 | system clock is divisible by 3600. The callback invocation times have |
1153 | system clock is divisible by 3600. The callback invocation times have |
1101 | potentially a lot of jittering, but good long-term stability. |
1154 | potentially a lot of jittering, but good long-term stability. |
1102 | .PP |
1155 | .PP |
… | |
… | |
1160 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1213 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1161 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1214 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1162 | .PD |
1215 | .PD |
1163 | Configures the watcher to trigger on the given signal number (usually one |
1216 | Configures the watcher to trigger on the given signal number (usually one |
1164 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1217 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1218 | .IP "int signum [read\-only]" 4 |
|
|
1219 | .IX Item "int signum [read-only]" |
|
|
1220 | The signal the watcher watches out for. |
1165 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1221 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1166 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1222 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1167 | .IX Subsection "ev_child - watch out for process status changes" |
1223 | .IX Subsection "ev_child - watch out for process status changes" |
1168 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1224 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1169 | some child status changes (most typically when a child of yours dies). |
1225 | some child status changes (most typically when a child of yours dies). |
… | |
… | |
1177 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1233 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1178 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1234 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1179 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1235 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1180 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1236 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1181 | process causing the status change. |
1237 | process causing the status change. |
|
|
1238 | .IP "int pid [read\-only]" 4 |
|
|
1239 | .IX Item "int pid [read-only]" |
|
|
1240 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1241 | .IP "int rpid [read\-write]" 4 |
|
|
1242 | .IX Item "int rpid [read-write]" |
|
|
1243 | The process id that detected a status change. |
|
|
1244 | .IP "int rstatus [read\-write]" 4 |
|
|
1245 | .IX Item "int rstatus [read-write]" |
|
|
1246 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1247 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1182 | .PP |
1248 | .PP |
1183 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1249 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1184 | .PP |
1250 | .PP |
1185 | .Vb 5 |
1251 | .Vb 5 |
1186 | \& static void |
1252 | \& static void |
… | |
… | |
1192 | .PP |
1258 | .PP |
1193 | .Vb 3 |
1259 | .Vb 3 |
1194 | \& struct ev_signal signal_watcher; |
1260 | \& struct ev_signal signal_watcher; |
1195 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1261 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1196 | \& ev_signal_start (loop, &sigint_cb); |
1262 | \& ev_signal_start (loop, &sigint_cb); |
|
|
1263 | .Ve |
|
|
1264 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1265 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1266 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1267 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1268 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1269 | compared to the last time, invoking the callback if it did. |
|
|
1270 | .PP |
|
|
1271 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1272 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1273 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1274 | otherwise always forced to be at least one) and all the other fields of |
|
|
1275 | the stat buffer having unspecified contents. |
|
|
1276 | .PP |
|
|
1277 | Since there is no standard to do this, the portable implementation simply |
|
|
1278 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
|
|
1279 | can specify a recommended polling interval for this case. If you specify |
|
|
1280 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1281 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1282 | five seconds, although this might change dynamically). Libev will also |
|
|
1283 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1284 | usually overkill. |
|
|
1285 | .PP |
|
|
1286 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1287 | as even with OS-supported change notifications, this can be |
|
|
1288 | resource\-intensive. |
|
|
1289 | .PP |
|
|
1290 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
|
|
1291 | if demand increases, at least a kqueue and inotify backend will be added. |
|
|
1292 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1293 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1294 | .PD 0 |
|
|
1295 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1296 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1297 | .PD |
|
|
1298 | Configures the watcher to wait for status changes of the given |
|
|
1299 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1300 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1301 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1302 | path for as long as the watcher is active. |
|
|
1303 | .Sp |
|
|
1304 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1305 | relative to the attributes at the time the watcher was started (or the |
|
|
1306 | last change was detected). |
|
|
1307 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1308 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1309 | Updates the stat buffer immediately with new values. If you change the |
|
|
1310 | watched path in your callback, you could call this fucntion to avoid |
|
|
1311 | detecting this change (while introducing a race condition). Can also be |
|
|
1312 | useful simply to find out the new values. |
|
|
1313 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1314 | .IX Item "ev_statdata attr [read-only]" |
|
|
1315 | The most-recently detected attributes of the file. Although the type is of |
|
|
1316 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1317 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1318 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1319 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1320 | .IX Item "ev_statdata prev [read-only]" |
|
|
1321 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1322 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1323 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1324 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1325 | The specified interval. |
|
|
1326 | .IP "const char *path [read\-only]" 4 |
|
|
1327 | .IX Item "const char *path [read-only]" |
|
|
1328 | The filesystem path that is being watched. |
|
|
1329 | .PP |
|
|
1330 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1331 | .PP |
|
|
1332 | .Vb 15 |
|
|
1333 | \& static void |
|
|
1334 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1335 | \& { |
|
|
1336 | \& /* /etc/passwd changed in some way */ |
|
|
1337 | \& if (w->attr.st_nlink) |
|
|
1338 | \& { |
|
|
1339 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1340 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1341 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1342 | \& } |
|
|
1343 | \& else |
|
|
1344 | \& /* you shalt not abuse printf for puts */ |
|
|
1345 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1346 | \& "if this is windows, they already arrived\en"); |
|
|
1347 | \& } |
|
|
1348 | .Ve |
|
|
1349 | .PP |
|
|
1350 | .Vb 2 |
|
|
1351 | \& ... |
|
|
1352 | \& ev_stat passwd; |
|
|
1353 | .Ve |
|
|
1354 | .PP |
|
|
1355 | .Vb 2 |
|
|
1356 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1357 | \& ev_stat_start (loop, &passwd); |
1197 | .Ve |
1358 | .Ve |
1198 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1359 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1199 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1360 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1200 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1361 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1201 | Idle watchers trigger events when there are no other events are pending |
1362 | Idle watchers trigger events when there are no other events are pending |
… | |
… | |
1242 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1403 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1243 | Prepare and check watchers are usually (but not always) used in tandem: |
1404 | Prepare and check watchers are usually (but not always) used in tandem: |
1244 | prepare watchers get invoked before the process blocks and check watchers |
1405 | prepare watchers get invoked before the process blocks and check watchers |
1245 | afterwards. |
1406 | afterwards. |
1246 | .PP |
1407 | .PP |
|
|
1408 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1409 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1410 | watchers. Other loops than the current one are fine, however. The |
|
|
1411 | rationale behind this is that you do not need to check for recursion in |
|
|
1412 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1413 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1414 | called in pairs bracketing the blocking call. |
|
|
1415 | .PP |
1247 | Their main purpose is to integrate other event mechanisms into libev and |
1416 | Their main purpose is to integrate other event mechanisms into libev and |
1248 | their use is somewhat advanced. This could be used, for example, to track |
1417 | their use is somewhat advanced. This could be used, for example, to track |
1249 | variable changes, implement your own watchers, integrate net-snmp or a |
1418 | variable changes, implement your own watchers, integrate net-snmp or a |
1250 | coroutine library and lots more. |
1419 | coroutine library and lots more. They are also occasionally useful if |
|
|
1420 | you cache some data and want to flush it before blocking (for example, |
|
|
1421 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1422 | watcher). |
1251 | .PP |
1423 | .PP |
1252 | This is done by examining in each prepare call which file descriptors need |
1424 | This is done by examining in each prepare call which file descriptors need |
1253 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1425 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1254 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1426 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1255 | provide just this functionality). Then, in the check watcher you check for |
1427 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1274 | .PD |
1446 | .PD |
1275 | Initialises and configures the prepare or check watcher \- they have no |
1447 | Initialises and configures the prepare or check watcher \- they have no |
1276 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1448 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1277 | macros, but using them is utterly, utterly and completely pointless. |
1449 | macros, but using them is utterly, utterly and completely pointless. |
1278 | .PP |
1450 | .PP |
1279 | Example: *TODO*. |
1451 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
|
|
1452 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1453 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1454 | pseudo-code only of course: |
|
|
1455 | .PP |
|
|
1456 | .Vb 2 |
|
|
1457 | \& static ev_io iow [nfd]; |
|
|
1458 | \& static ev_timer tw; |
|
|
1459 | .Ve |
|
|
1460 | .PP |
|
|
1461 | .Vb 9 |
|
|
1462 | \& static void |
|
|
1463 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1464 | \& { |
|
|
1465 | \& // set the relevant poll flags |
|
|
1466 | \& // could also call adns_processreadable etc. here |
|
|
1467 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1468 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1469 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1470 | \& } |
|
|
1471 | .Ve |
|
|
1472 | .PP |
|
|
1473 | .Vb 7 |
|
|
1474 | \& // create io watchers for each fd and a timer before blocking |
|
|
1475 | \& static void |
|
|
1476 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1477 | \& { |
|
|
1478 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1479 | \& // actual code will need to loop here and realloc etc. |
|
|
1480 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1481 | .Ve |
|
|
1482 | .PP |
|
|
1483 | .Vb 3 |
|
|
1484 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1485 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1486 | \& ev_timer_start (loop, &tw); |
|
|
1487 | .Ve |
|
|
1488 | .PP |
|
|
1489 | .Vb 6 |
|
|
1490 | \& // create on ev_io per pollfd |
|
|
1491 | \& for (int i = 0; i < nfd; ++i) |
|
|
1492 | \& { |
|
|
1493 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1494 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1495 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1496 | .Ve |
|
|
1497 | .PP |
|
|
1498 | .Vb 5 |
|
|
1499 | \& fds [i].revents = 0; |
|
|
1500 | \& iow [i].data = fds + i; |
|
|
1501 | \& ev_io_start (loop, iow + i); |
|
|
1502 | \& } |
|
|
1503 | \& } |
|
|
1504 | .Ve |
|
|
1505 | .PP |
|
|
1506 | .Vb 5 |
|
|
1507 | \& // stop all watchers after blocking |
|
|
1508 | \& static void |
|
|
1509 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1510 | \& { |
|
|
1511 | \& ev_timer_stop (loop, &tw); |
|
|
1512 | .Ve |
|
|
1513 | .PP |
|
|
1514 | .Vb 2 |
|
|
1515 | \& for (int i = 0; i < nfd; ++i) |
|
|
1516 | \& ev_io_stop (loop, iow + i); |
|
|
1517 | .Ve |
|
|
1518 | .PP |
|
|
1519 | .Vb 2 |
|
|
1520 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1521 | \& } |
|
|
1522 | .Ve |
1280 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1523 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1281 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1524 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1282 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1525 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1283 | This is a rather advanced watcher type that lets you embed one event loop |
1526 | This is a rather advanced watcher type that lets you embed one event loop |
1284 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1527 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
… | |
… | |
1367 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1610 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1368 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1611 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1369 | Make a single, non-blocking sweep over the embedded loop. This works |
1612 | Make a single, non-blocking sweep over the embedded loop. This works |
1370 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1613 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1371 | apropriate way for embedded loops. |
1614 | apropriate way for embedded loops. |
|
|
1615 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1616 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1617 | The embedded event loop. |
1372 | .SH "OTHER FUNCTIONS" |
1618 | .SH "OTHER FUNCTIONS" |
1373 | .IX Header "OTHER FUNCTIONS" |
1619 | .IX Header "OTHER FUNCTIONS" |
1374 | There are some other functions of possible interest. Described. Here. Now. |
1620 | There are some other functions of possible interest. Described. Here. Now. |
1375 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1621 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1376 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1622 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1515 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1761 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1516 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
1762 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
1517 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
1763 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
1518 | .IX Item "w->sweep () ev::embed only" |
1764 | .IX Item "w->sweep () ev::embed only" |
1519 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
1765 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1766 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
1767 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
1768 | .IX Item "w->update () ev::stat only" |
|
|
1769 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1520 | .RE |
1770 | .RE |
1521 | .RS 4 |
1771 | .RS 4 |
1522 | .RE |
1772 | .RE |
1523 | .PP |
1773 | .PP |
1524 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
1774 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
… | |
… | |
1757 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2007 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
1758 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2008 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
1759 | additional independent event loops. Otherwise there will be no support |
2009 | additional independent event loops. Otherwise there will be no support |
1760 | for multiple event loops and there is no first event loop pointer |
2010 | for multiple event loops and there is no first event loop pointer |
1761 | argument. Instead, all functions act on the single default loop. |
2011 | argument. Instead, all functions act on the single default loop. |
1762 | .IP "\s-1EV_PERIODICS\s0" 4 |
2012 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
1763 | .IX Item "EV_PERIODICS" |
2013 | .IX Item "EV_PERIODIC_ENABLE" |
1764 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported, |
2014 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
1765 | otherwise not. This saves a few kb of code. |
2015 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2016 | code. |
|
|
2017 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2018 | .IX Item "EV_EMBED_ENABLE" |
|
|
2019 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2020 | defined to be \f(CW0\fR, then they are not. |
|
|
2021 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2022 | .IX Item "EV_STAT_ENABLE" |
|
|
2023 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2024 | defined to be \f(CW0\fR, then they are not. |
|
|
2025 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2026 | .IX Item "EV_MINIMAL" |
|
|
2027 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2028 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2029 | some inlining decisions, saves roughly 30% codesize of amd64. |
1766 | .IP "\s-1EV_COMMON\s0" 4 |
2030 | .IP "\s-1EV_COMMON\s0" 4 |
1767 | .IX Item "EV_COMMON" |
2031 | .IX Item "EV_COMMON" |
1768 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2032 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
1769 | this macro to a something else you can include more and other types of |
2033 | this macro to a something else you can include more and other types of |
1770 | members. You have to define it each time you include one of the files, |
2034 | members. You have to define it each time you include one of the files, |
… | |
… | |
1819 | .Sp |
2083 | .Sp |
1820 | .Vb 2 |
2084 | .Vb 2 |
1821 | \& #include "ev_cpp.h" |
2085 | \& #include "ev_cpp.h" |
1822 | \& #include "ev.c" |
2086 | \& #include "ev.c" |
1823 | .Ve |
2087 | .Ve |
|
|
2088 | .SH "COMPLEXITIES" |
|
|
2089 | .IX Header "COMPLEXITIES" |
|
|
2090 | In this section the complexities of (many of) the algorithms used inside |
|
|
2091 | libev will be explained. For complexity discussions about backends see the |
|
|
2092 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2093 | .RS 4 |
|
|
2094 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
|
|
2095 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
|
|
2096 | .PD 0 |
|
|
2097 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
|
|
2098 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2099 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2100 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2101 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
|
|
2102 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2103 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 |
|
|
2104 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" |
|
|
2105 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
|
|
2106 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2107 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2108 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2109 | .IP "Activating one watcher: O(1)" 4 |
|
|
2110 | .IX Item "Activating one watcher: O(1)" |
|
|
2111 | .RE |
|
|
2112 | .RS 4 |
|
|
2113 | .PD |
1824 | .SH "AUTHOR" |
2114 | .SH "AUTHOR" |
1825 | .IX Header "AUTHOR" |
2115 | .IX Header "AUTHOR" |
1826 | Marc Lehmann <libev@schmorp.de>. |
2116 | Marc Lehmann <libev@schmorp.de>. |