| … | |
… | |
| 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 "2007-11-26" "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 |
| … | |
… | |
| 240 | might be supported on the current system, you would need to look at |
240 | might be supported on the current system, you would need to look at |
| 241 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
241 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
| 242 | recommended ones. |
242 | recommended ones. |
| 243 | .Sp |
243 | .Sp |
| 244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
| 245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4 |
| 246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" |
| 247 | Sets the allocation function to use (the prototype is similar to the |
247 | Sets the allocation function to use (the prototype and semantics are |
| 248 | realloc C function, the semantics are identical). It is used to allocate |
248 | identical to the realloc C function). It is used to allocate and free |
| 249 | and free memory (no surprises here). If it returns zero when memory |
249 | memory (no surprises here). If it returns zero when memory needs to be |
| 250 | needs to be allocated, the library might abort or take some potentially |
250 | allocated, the library might abort or take some potentially destructive |
| 251 | destructive action. The default is your system realloc function. |
251 | action. The default is your system realloc function. |
| 252 | .Sp |
252 | .Sp |
| 253 | You could override this function in high-availability programs to, say, |
253 | You could override this function in high-availability programs to, say, |
| 254 | free some memory if it cannot allocate memory, to use a special allocator, |
254 | free some memory if it cannot allocate memory, to use a special allocator, |
| 255 | or even to sleep a while and retry until some memory is available. |
255 | or even to sleep a while and retry until some memory is available. |
| 256 | .Sp |
256 | .Sp |
| 257 | Example: replace the libev allocator with one that waits a bit and then |
257 | Example: replace the libev allocator with one that waits a bit and then |
| 258 | retries: better than mine). |
258 | retries: better than mine). |
| 259 | .Sp |
259 | .Sp |
| 260 | .Vb 6 |
260 | .Vb 6 |
| 261 | \& static void * |
261 | \& static void * |
| 262 | \& persistent_realloc (void *ptr, long size) |
262 | \& persistent_realloc (void *ptr, size_t size) |
| 263 | \& { |
263 | \& { |
| 264 | \& for (;;) |
264 | \& for (;;) |
| 265 | \& { |
265 | \& { |
| 266 | \& void *newptr = realloc (ptr, size); |
266 | \& void *newptr = realloc (ptr, size); |
| 267 | .Ve |
267 | .Ve |
| … | |
… | |
| 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 |
| … | |
… | |
| 703 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
707 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
| 704 | received events. Callbacks of both watcher types can start and stop as |
708 | received events. Callbacks of both watcher types can start and stop as |
| 705 | many watchers as they want, and all of them will be taken into account |
709 | many watchers as they want, and all of them will be taken into account |
| 706 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
710 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
| 707 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
711 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
712 | .ie n .IP """EV_EMBED""" 4 |
|
|
713 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
714 | .IX Item "EV_EMBED" |
|
|
715 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
716 | .ie n .IP """EV_FORK""" 4 |
|
|
717 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
718 | .IX Item "EV_FORK" |
|
|
719 | The event loop has been resumed in the child process after fork (see |
|
|
720 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
| 708 | .ie n .IP """EV_ERROR""" 4 |
721 | .ie n .IP """EV_ERROR""" 4 |
| 709 | .el .IP "\f(CWEV_ERROR\fR" 4 |
722 | .el .IP "\f(CWEV_ERROR\fR" 4 |
| 710 | .IX Item "EV_ERROR" |
723 | .IX Item "EV_ERROR" |
| 711 | An unspecified error has occured, the watcher has been stopped. This might |
724 | An unspecified error has occured, the watcher has been stopped. This might |
| 712 | happen because the watcher could not be properly started because libev |
725 | happen because the watcher could not be properly started because libev |
| … | |
… | |
| 821 | More interesting and less C\-conformant ways of catsing your callback type |
834 | More interesting and less C\-conformant ways of catsing your callback type |
| 822 | have been omitted.... |
835 | have been omitted.... |
| 823 | .SH "WATCHER TYPES" |
836 | .SH "WATCHER TYPES" |
| 824 | .IX Header "WATCHER TYPES" |
837 | .IX Header "WATCHER TYPES" |
| 825 | This section describes each watcher in detail, but will not repeat |
838 | This section describes each watcher in detail, but will not repeat |
| 826 | information given in the last section. |
839 | information given in the last section. Any initialisation/set macros, |
|
|
840 | functions and members specific to the watcher type are explained. |
|
|
841 | .PP |
|
|
842 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
843 | while the watcher is active, you can look at the member and expect some |
|
|
844 | sensible content, but you must not modify it (you can modify it while the |
|
|
845 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
846 | means you can expect it to have some sensible content while the watcher |
|
|
847 | is active, but you can also modify it. Modifying it may not do something |
|
|
848 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
849 | not crash or malfunction in any way. |
| 827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
850 | .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?" |
851 | .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?" |
852 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
| 830 | I/O watchers check whether a file descriptor is readable or writable |
853 | 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 |
854 | in each iteration of the event loop, or, more precisely, when reading |
| … | |
… | |
| 871 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
894 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
| 872 | .PD |
895 | .PD |
| 873 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
896 | 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 |
897 | 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. |
898 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
|
|
899 | .IP "int fd [read\-only]" 4 |
|
|
900 | .IX Item "int fd [read-only]" |
|
|
901 | The file descriptor being watched. |
|
|
902 | .IP "int events [read\-only]" 4 |
|
|
903 | .IX Item "int events [read-only]" |
|
|
904 | The events being watched. |
| 876 | .PP |
905 | .PP |
| 877 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
906 | 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 |
907 | readable, but only once. Since it is likely line\-buffered, you could |
| 879 | attempt to read a whole line in the callback: |
908 | attempt to read a whole line in the callback: |
| 880 | .PP |
909 | .PP |
| … | |
… | |
| 945 | .Sp |
974 | .Sp |
| 946 | If the timer is repeating, either start it if necessary (with the repeat |
975 | If the timer is repeating, either start it if necessary (with the repeat |
| 947 | value), or reset the running timer to the repeat value. |
976 | value), or reset the running timer to the repeat value. |
| 948 | .Sp |
977 | .Sp |
| 949 | This sounds a bit complicated, but here is a useful and typical |
978 | 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 |
979 | 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 |
980 | 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 |
981 | 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 |
982 | 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 |
983 | \&\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 |
984 | 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. |
985 | socket, you can stop the timer, and again will automatically restart it if |
|
|
986 | need be. |
|
|
987 | .Sp |
|
|
988 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
|
|
989 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
|
|
990 | .Sp |
|
|
991 | .Vb 8 |
|
|
992 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
993 | \& ev_timer_again (loop, timer); |
|
|
994 | \& ... |
|
|
995 | \& timer->again = 17.; |
|
|
996 | \& ev_timer_again (loop, timer); |
|
|
997 | \& ... |
|
|
998 | \& timer->again = 10.; |
|
|
999 | \& ev_timer_again (loop, timer); |
|
|
1000 | .Ve |
|
|
1001 | .Sp |
|
|
1002 | This is more efficient then stopping/starting the timer eahc time you want |
|
|
1003 | to modify its timeout value. |
|
|
1004 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1005 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1006 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1007 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1008 | which is also when any modifications are taken into account. |
| 957 | .PP |
1009 | .PP |
| 958 | Example: create a timer that fires after 60 seconds. |
1010 | Example: create a timer that fires after 60 seconds. |
| 959 | .PP |
1011 | .PP |
| 960 | .Vb 5 |
1012 | .Vb 5 |
| 961 | \& static void |
1013 | \& static void |
| … | |
… | |
| 1093 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1145 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
| 1094 | Simply stops and restarts the periodic watcher again. This is only useful |
1146 | Simply stops and restarts the periodic watcher again. This is only useful |
| 1095 | when you changed some parameters or the reschedule callback would return |
1147 | 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 |
1148 | a different time than the last time it was called (e.g. in a crond like |
| 1097 | program when the crontabs have changed). |
1149 | program when the crontabs have changed). |
|
|
1150 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1151 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1152 | The current interval value. Can be modified any time, but changes only |
|
|
1153 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1154 | called. |
|
|
1155 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1156 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1157 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1158 | switched off. Can be changed any time, but changes only take effect when |
|
|
1159 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
| 1098 | .PP |
1160 | .PP |
| 1099 | Example: call a callback every hour, or, more precisely, whenever the |
1161 | Example: call a callback every hour, or, more precisely, whenever the |
| 1100 | system clock is divisible by 3600. The callback invocation times have |
1162 | system clock is divisible by 3600. The callback invocation times have |
| 1101 | potentially a lot of jittering, but good long-term stability. |
1163 | potentially a lot of jittering, but good long-term stability. |
| 1102 | .PP |
1164 | .PP |
| … | |
… | |
| 1160 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1222 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
| 1161 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1223 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
| 1162 | .PD |
1224 | .PD |
| 1163 | Configures the watcher to trigger on the given signal number (usually one |
1225 | Configures the watcher to trigger on the given signal number (usually one |
| 1164 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1226 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1227 | .IP "int signum [read\-only]" 4 |
|
|
1228 | .IX Item "int signum [read-only]" |
|
|
1229 | The signal the watcher watches out for. |
| 1165 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1230 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
| 1166 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1231 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
| 1167 | .IX Subsection "ev_child - watch out for process status changes" |
1232 | .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 |
1233 | 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). |
1234 | 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 |
1242 | \&\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 |
1243 | 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 |
1244 | 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 |
1245 | \&\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. |
1246 | process causing the status change. |
|
|
1247 | .IP "int pid [read\-only]" 4 |
|
|
1248 | .IX Item "int pid [read-only]" |
|
|
1249 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1250 | .IP "int rpid [read\-write]" 4 |
|
|
1251 | .IX Item "int rpid [read-write]" |
|
|
1252 | The process id that detected a status change. |
|
|
1253 | .IP "int rstatus [read\-write]" 4 |
|
|
1254 | .IX Item "int rstatus [read-write]" |
|
|
1255 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1256 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
| 1182 | .PP |
1257 | .PP |
| 1183 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1258 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
| 1184 | .PP |
1259 | .PP |
| 1185 | .Vb 5 |
1260 | .Vb 5 |
| 1186 | \& static void |
1261 | \& static void |
| … | |
… | |
| 1192 | .PP |
1267 | .PP |
| 1193 | .Vb 3 |
1268 | .Vb 3 |
| 1194 | \& struct ev_signal signal_watcher; |
1269 | \& struct ev_signal signal_watcher; |
| 1195 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1270 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
| 1196 | \& ev_signal_start (loop, &sigint_cb); |
1271 | \& ev_signal_start (loop, &sigint_cb); |
|
|
1272 | .Ve |
|
|
1273 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1274 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1275 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1276 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1277 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1278 | compared to the last time, invoking the callback if it did. |
|
|
1279 | .PP |
|
|
1280 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1281 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1282 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1283 | otherwise always forced to be at least one) and all the other fields of |
|
|
1284 | the stat buffer having unspecified contents. |
|
|
1285 | .PP |
|
|
1286 | Since there is no standard to do this, the portable implementation simply |
|
|
1287 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
|
|
1288 | can specify a recommended polling interval for this case. If you specify |
|
|
1289 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1290 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1291 | five seconds, although this might change dynamically). Libev will also |
|
|
1292 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1293 | usually overkill. |
|
|
1294 | .PP |
|
|
1295 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1296 | as even with OS-supported change notifications, this can be |
|
|
1297 | resource\-intensive. |
|
|
1298 | .PP |
|
|
1299 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
|
|
1300 | if demand increases, at least a kqueue and inotify backend will be added. |
|
|
1301 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1302 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1303 | .PD 0 |
|
|
1304 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1305 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1306 | .PD |
|
|
1307 | Configures the watcher to wait for status changes of the given |
|
|
1308 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1309 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1310 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1311 | path for as long as the watcher is active. |
|
|
1312 | .Sp |
|
|
1313 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1314 | relative to the attributes at the time the watcher was started (or the |
|
|
1315 | last change was detected). |
|
|
1316 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1317 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1318 | Updates the stat buffer immediately with new values. If you change the |
|
|
1319 | watched path in your callback, you could call this fucntion to avoid |
|
|
1320 | detecting this change (while introducing a race condition). Can also be |
|
|
1321 | useful simply to find out the new values. |
|
|
1322 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1323 | .IX Item "ev_statdata attr [read-only]" |
|
|
1324 | The most-recently detected attributes of the file. Although the type is of |
|
|
1325 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1326 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1327 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1328 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1329 | .IX Item "ev_statdata prev [read-only]" |
|
|
1330 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1331 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1332 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1333 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1334 | The specified interval. |
|
|
1335 | .IP "const char *path [read\-only]" 4 |
|
|
1336 | .IX Item "const char *path [read-only]" |
|
|
1337 | The filesystem path that is being watched. |
|
|
1338 | .PP |
|
|
1339 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1340 | .PP |
|
|
1341 | .Vb 15 |
|
|
1342 | \& static void |
|
|
1343 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1344 | \& { |
|
|
1345 | \& /* /etc/passwd changed in some way */ |
|
|
1346 | \& if (w->attr.st_nlink) |
|
|
1347 | \& { |
|
|
1348 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1349 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1350 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1351 | \& } |
|
|
1352 | \& else |
|
|
1353 | \& /* you shalt not abuse printf for puts */ |
|
|
1354 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1355 | \& "if this is windows, they already arrived\en"); |
|
|
1356 | \& } |
|
|
1357 | .Ve |
|
|
1358 | .PP |
|
|
1359 | .Vb 2 |
|
|
1360 | \& ... |
|
|
1361 | \& ev_stat passwd; |
|
|
1362 | .Ve |
|
|
1363 | .PP |
|
|
1364 | .Vb 2 |
|
|
1365 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1366 | \& ev_stat_start (loop, &passwd); |
| 1197 | .Ve |
1367 | .Ve |
| 1198 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1368 | .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..." |
1369 | .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..." |
1370 | .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 |
1371 | Idle watchers trigger events when there are no other events are pending |
| … | |
… | |
| 1449 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1619 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
| 1450 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1620 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
| 1451 | Make a single, non-blocking sweep over the embedded loop. This works |
1621 | Make a single, non-blocking sweep over the embedded loop. This works |
| 1452 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1622 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
| 1453 | apropriate way for embedded loops. |
1623 | apropriate way for embedded loops. |
|
|
1624 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1625 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1626 | The embedded event loop. |
|
|
1627 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1628 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1629 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1630 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1631 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1632 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1633 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1634 | and only in the child after the fork. If whoever good citizen calling |
|
|
1635 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1636 | handlers will be invoked, too, of course. |
|
|
1637 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
1638 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
1639 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1640 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1641 | believe me. |
| 1454 | .SH "OTHER FUNCTIONS" |
1642 | .SH "OTHER FUNCTIONS" |
| 1455 | .IX Header "OTHER FUNCTIONS" |
1643 | .IX Header "OTHER FUNCTIONS" |
| 1456 | There are some other functions of possible interest. Described. Here. Now. |
1644 | There are some other functions of possible interest. Described. Here. Now. |
| 1457 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1645 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
| 1458 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1646 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
| … | |
… | |
| 1597 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1785 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
| 1598 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
1786 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
| 1599 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
1787 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
| 1600 | .IX Item "w->sweep () ev::embed only" |
1788 | .IX Item "w->sweep () ev::embed only" |
| 1601 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
1789 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1790 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
1791 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
1792 | .IX Item "w->update () ev::stat only" |
|
|
1793 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
| 1602 | .RE |
1794 | .RE |
| 1603 | .RS 4 |
1795 | .RS 4 |
| 1604 | .RE |
1796 | .RE |
| 1605 | .PP |
1797 | .PP |
| 1606 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
1798 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
| … | |
… | |
| 1623 | \& : io (this, &myclass::io_cb), |
1815 | \& : io (this, &myclass::io_cb), |
| 1624 | \& idle (this, &myclass::idle_cb) |
1816 | \& idle (this, &myclass::idle_cb) |
| 1625 | \& { |
1817 | \& { |
| 1626 | \& io.start (fd, ev::READ); |
1818 | \& io.start (fd, ev::READ); |
| 1627 | \& } |
1819 | \& } |
|
|
1820 | .Ve |
|
|
1821 | .SH "MACRO MAGIC" |
|
|
1822 | .IX Header "MACRO MAGIC" |
|
|
1823 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1824 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
|
|
1825 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
1826 | .PP |
|
|
1827 | To make it easier to write programs that cope with either variant, the |
|
|
1828 | following macros are defined: |
|
|
1829 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
1830 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
1831 | .IX Item "EV_A, EV_A_" |
|
|
1832 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
1833 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
1834 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
1835 | .Sp |
|
|
1836 | .Vb 3 |
|
|
1837 | \& ev_unref (EV_A); |
|
|
1838 | \& ev_timer_add (EV_A_ watcher); |
|
|
1839 | \& ev_loop (EV_A_ 0); |
|
|
1840 | .Ve |
|
|
1841 | .Sp |
|
|
1842 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
1843 | which is often provided by the following macro. |
|
|
1844 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
1845 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
1846 | .IX Item "EV_P, EV_P_" |
|
|
1847 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
1848 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
1849 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
1850 | .Sp |
|
|
1851 | .Vb 2 |
|
|
1852 | \& // this is how ev_unref is being declared |
|
|
1853 | \& static void ev_unref (EV_P); |
|
|
1854 | .Ve |
|
|
1855 | .Sp |
|
|
1856 | .Vb 2 |
|
|
1857 | \& // this is how you can declare your typical callback |
|
|
1858 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1859 | .Ve |
|
|
1860 | .Sp |
|
|
1861 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
1862 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
1863 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
1864 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
1865 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
1866 | Similar to the other two macros, this gives you the value of the default |
|
|
1867 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
1868 | .PP |
|
|
1869 | Example: Declare and initialise a check watcher, working regardless of |
|
|
1870 | wether multiple loops are supported or not. |
|
|
1871 | .PP |
|
|
1872 | .Vb 5 |
|
|
1873 | \& static void |
|
|
1874 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1875 | \& { |
|
|
1876 | \& ev_check_stop (EV_A_ w); |
|
|
1877 | \& } |
|
|
1878 | .Ve |
|
|
1879 | .PP |
|
|
1880 | .Vb 4 |
|
|
1881 | \& ev_check check; |
|
|
1882 | \& ev_check_init (&check, check_cb); |
|
|
1883 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
1884 | \& ev_loop (EV_DEFAULT_ 0); |
| 1628 | .Ve |
1885 | .Ve |
| 1629 | .SH "EMBEDDING" |
1886 | .SH "EMBEDDING" |
| 1630 | .IX Header "EMBEDDING" |
1887 | .IX Header "EMBEDDING" |
| 1631 | Libev can (and often is) directly embedded into host |
1888 | Libev can (and often is) directly embedded into host |
| 1632 | applications. Examples of applications that embed it include the Deliantra |
1889 | applications. Examples of applications that embed it include the Deliantra |
| … | |
… | |
| 1839 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2096 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
| 1840 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2097 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
| 1841 | additional independent event loops. Otherwise there will be no support |
2098 | additional independent event loops. Otherwise there will be no support |
| 1842 | for multiple event loops and there is no first event loop pointer |
2099 | for multiple event loops and there is no first event loop pointer |
| 1843 | argument. Instead, all functions act on the single default loop. |
2100 | argument. Instead, all functions act on the single default loop. |
| 1844 | .IP "\s-1EV_PERIODICS\s0" 4 |
2101 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
| 1845 | .IX Item "EV_PERIODICS" |
2102 | .IX Item "EV_PERIODIC_ENABLE" |
| 1846 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported, |
2103 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
| 1847 | otherwise not. This saves a few kb of code. |
2104 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2105 | code. |
|
|
2106 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2107 | .IX Item "EV_EMBED_ENABLE" |
|
|
2108 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2109 | defined to be \f(CW0\fR, then they are not. |
|
|
2110 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2111 | .IX Item "EV_STAT_ENABLE" |
|
|
2112 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2113 | defined to be \f(CW0\fR, then they are not. |
|
|
2114 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2115 | .IX Item "EV_FORK_ENABLE" |
|
|
2116 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2117 | defined to be \f(CW0\fR, then they are not. |
|
|
2118 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2119 | .IX Item "EV_MINIMAL" |
|
|
2120 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2121 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2122 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2123 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2124 | .IX Item "EV_PID_HASHSIZE" |
|
|
2125 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2126 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2127 | than enough. If you need to manage thousands of children you might want to |
|
|
2128 | increase this value. |
| 1848 | .IP "\s-1EV_COMMON\s0" 4 |
2129 | .IP "\s-1EV_COMMON\s0" 4 |
| 1849 | .IX Item "EV_COMMON" |
2130 | .IX Item "EV_COMMON" |
| 1850 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2131 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
| 1851 | this macro to a something else you can include more and other types of |
2132 | this macro to a something else you can include more and other types of |
| 1852 | members. You have to define it each time you include one of the files, |
2133 | members. You have to define it each time you include one of the files, |
