… | |
… | |
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 "2007-11-28" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-08" "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 |
… | |
… | |
196 | \& return 0; |
196 | \& return 0; |
197 | \& } |
197 | \& } |
198 | .Ve |
198 | .Ve |
199 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
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|
201 | The newest version of this document is also available as a html-formatted |
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202 | web page you might find easier to navigate when reading it for the first |
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203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
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|
204 | .PP |
201 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
202 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occuring), and it will manage |
203 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
204 | .PP |
208 | .PP |
205 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
… | |
… | |
411 | or setgid) then libev will \fInot\fR look at the environment variable |
415 | or setgid) then libev will \fInot\fR look at the environment variable |
412 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
416 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
413 | override the flags completely if it is found in the environment. This is |
417 | override the flags completely if it is found in the environment. This is |
414 | useful to try out specific backends to test their performance, or to work |
418 | useful to try out specific backends to test their performance, or to work |
415 | around bugs. |
419 | around bugs. |
|
|
420 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
|
|
421 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
|
|
422 | .IX Item "EVFLAG_FORKCHECK" |
|
|
423 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
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|
424 | a fork, you can also make libev check for a fork in each iteration by |
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|
425 | enabling this flag. |
|
|
426 | .Sp |
|
|
427 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
|
|
428 | and thus this might slow down your event loop if you do a lot of loop |
|
|
429 | iterations and little real work, but is usually not noticeable (on my |
|
|
430 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
|
|
431 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
|
|
432 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
|
|
433 | .Sp |
|
|
434 | The big advantage of this flag is that you can forget about fork (and |
|
|
435 | forget about forgetting to tell libev about forking) when you use this |
|
|
436 | flag. |
|
|
437 | .Sp |
|
|
438 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
|
|
439 | environment variable. |
416 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
440 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
417 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
441 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
418 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
442 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
419 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
443 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
420 | libev tries to roll its own fd_set with no limits on the number of fds, |
444 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
561 | .IP "ev_loop_fork (loop)" 4 |
585 | .IP "ev_loop_fork (loop)" 4 |
562 | .IX Item "ev_loop_fork (loop)" |
586 | .IX Item "ev_loop_fork (loop)" |
563 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
587 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
564 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
588 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
565 | after fork, and how you do this is entirely your own problem. |
589 | after fork, and how you do this is entirely your own problem. |
|
|
590 | .IP "unsigned int ev_loop_count (loop)" 4 |
|
|
591 | .IX Item "unsigned int ev_loop_count (loop)" |
|
|
592 | Returns the count of loop iterations for the loop, which is identical to |
|
|
593 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
|
|
594 | happily wraps around with enough iterations. |
|
|
595 | .Sp |
|
|
596 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
597 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
|
|
598 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
566 | .IP "unsigned int ev_backend (loop)" 4 |
599 | .IP "unsigned int ev_backend (loop)" 4 |
567 | .IX Item "unsigned int ev_backend (loop)" |
600 | .IX Item "unsigned int ev_backend (loop)" |
568 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
601 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
569 | use. |
602 | use. |
570 | .IP "ev_tstamp ev_now (loop)" 4 |
603 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
601 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
634 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
602 | usually a better approach for this kind of thing. |
635 | usually a better approach for this kind of thing. |
603 | .Sp |
636 | .Sp |
604 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
637 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
605 | .Sp |
638 | .Sp |
606 | .Vb 18 |
639 | .Vb 19 |
|
|
640 | \& - Before the first iteration, call any pending watchers. |
607 | \& * If there are no active watchers (reference count is zero), return. |
641 | \& * If there are no active watchers (reference count is zero), return. |
608 | \& - Queue prepare watchers and then call all outstanding watchers. |
642 | \& - Queue all prepare watchers and then call all outstanding watchers. |
609 | \& - If we have been forked, recreate the kernel state. |
643 | \& - If we have been forked, recreate the kernel state. |
610 | \& - Update the kernel state with all outstanding changes. |
644 | \& - Update the kernel state with all outstanding changes. |
611 | \& - Update the "event loop time". |
645 | \& - Update the "event loop time". |
612 | \& - Calculate for how long to block. |
646 | \& - Calculate for how long to block. |
613 | \& - Block the process, waiting for any events. |
647 | \& - Block the process, waiting for any events. |
… | |
… | |
856 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
890 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
857 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
891 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
858 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
892 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
859 | events but its callback has not yet been invoked). As long as a watcher |
893 | events but its callback has not yet been invoked). As long as a watcher |
860 | is pending (but not active) you must not call an init function on it (but |
894 | is pending (but not active) you must not call an init function on it (but |
861 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
895 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
862 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
896 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
897 | it). |
863 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
898 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
864 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
899 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
865 | Returns the callback currently set on the watcher. |
900 | Returns the callback currently set on the watcher. |
866 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
901 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
867 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
902 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
868 | Change the callback. You can change the callback at virtually any time |
903 | Change the callback. You can change the callback at virtually any time |
869 | (modulo threads). |
904 | (modulo threads). |
|
|
905 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
906 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
907 | .PD 0 |
|
|
908 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
909 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
910 | .PD |
|
|
911 | Set and query the priority of the watcher. The priority is a small |
|
|
912 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
913 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
914 | before watchers with lower priority, but priority will not keep watchers |
|
|
915 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
916 | .Sp |
|
|
917 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
918 | invocation after new events have been received. This is useful, for |
|
|
919 | example, to reduce latency after idling, or more often, to bind two |
|
|
920 | watchers on the same event and make sure one is called first. |
|
|
921 | .Sp |
|
|
922 | If you need to suppress invocation when higher priority events are pending |
|
|
923 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
924 | .Sp |
|
|
925 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
926 | pending. |
|
|
927 | .Sp |
|
|
928 | The default priority used by watchers when no priority has been set is |
|
|
929 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
930 | .Sp |
|
|
931 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
932 | fine, as long as you do not mind that the priority value you query might |
|
|
933 | or might not have been adjusted to be within valid range. |
|
|
934 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
935 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
936 | Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither |
|
|
937 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
938 | can deal with that fact. |
|
|
939 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
940 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
941 | If the watcher is pending, this function returns clears its pending status |
|
|
942 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
943 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
870 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
944 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
871 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
945 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
872 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
946 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
873 | and read at any time, libev will completely ignore it. This can be used |
947 | and read at any time, libev will completely ignore it. This can be used |
874 | to associate arbitrary data with your watcher. If you need more data and |
948 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
985 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1059 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
986 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1060 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
987 | .PP |
1061 | .PP |
988 | If you cannot run the fd in non-blocking mode (for example you should not |
1062 | If you cannot run the fd in non-blocking mode (for example you should not |
989 | play around with an Xlib connection), then you have to seperately re-test |
1063 | play around with an Xlib connection), then you have to seperately re-test |
990 | wether a file descriptor is really ready with a known-to-be good interface |
1064 | whether a file descriptor is really ready with a known-to-be good interface |
991 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1065 | such as poll (fortunately in our Xlib example, Xlib already does this on |
992 | its own, so its quite safe to use). |
1066 | its own, so its quite safe to use). |
993 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1067 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
994 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1068 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
995 | .PD 0 |
1069 | .PD 0 |
… | |
… | |
1071 | .IP "ev_timer_again (loop)" 4 |
1145 | .IP "ev_timer_again (loop)" 4 |
1072 | .IX Item "ev_timer_again (loop)" |
1146 | .IX Item "ev_timer_again (loop)" |
1073 | This will act as if the timer timed out and restart it again if it is |
1147 | This will act as if the timer timed out and restart it again if it is |
1074 | repeating. The exact semantics are: |
1148 | repeating. The exact semantics are: |
1075 | .Sp |
1149 | .Sp |
|
|
1150 | If the timer is pending, its pending status is cleared. |
|
|
1151 | .Sp |
1076 | If the timer is started but nonrepeating, stop it. |
1152 | If the timer is started but nonrepeating, stop it (as if it timed out). |
1077 | .Sp |
1153 | .Sp |
1078 | If the timer is repeating, either start it if necessary (with the repeat |
1154 | If the timer is repeating, either start it if necessary (with the |
1079 | value), or reset the running timer to the repeat value. |
1155 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1080 | .Sp |
1156 | .Sp |
1081 | This sounds a bit complicated, but here is a useful and typical |
1157 | This sounds a bit complicated, but here is a useful and typical |
1082 | example: Imagine you have a tcp connection and you want a so-called |
1158 | example: Imagine you have a tcp connection and you want a so-called idle |
1083 | idle timeout, that is, you want to be called when there have been, |
1159 | timeout, that is, you want to be called when there have been, say, 60 |
1084 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1160 | seconds of inactivity on the socket. The easiest way to do this is to |
1085 | 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 |
1161 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
1086 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1162 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1087 | you go into an idle state where you do not expect data to travel on the |
1163 | you go into an idle state where you do not expect data to travel on the |
1088 | socket, you can stop the timer, and again will automatically restart it if |
1164 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
1089 | need be. |
1165 | automatically restart it if need be. |
1090 | .Sp |
1166 | .Sp |
1091 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1167 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
1092 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
1168 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
1093 | .Sp |
1169 | .Sp |
1094 | .Vb 8 |
1170 | .Vb 8 |
1095 | \& ev_timer_init (timer, callback, 0., 5.); |
1171 | \& ev_timer_init (timer, callback, 0., 5.); |
1096 | \& ev_timer_again (loop, timer); |
1172 | \& ev_timer_again (loop, timer); |
1097 | \& ... |
1173 | \& ... |
… | |
… | |
1100 | \& ... |
1176 | \& ... |
1101 | \& timer->again = 10.; |
1177 | \& timer->again = 10.; |
1102 | \& ev_timer_again (loop, timer); |
1178 | \& ev_timer_again (loop, timer); |
1103 | .Ve |
1179 | .Ve |
1104 | .Sp |
1180 | .Sp |
1105 | This is more efficient then stopping/starting the timer eahc time you want |
1181 | This is more slightly efficient then stopping/starting the timer each time |
1106 | to modify its timeout value. |
1182 | you want to modify its timeout value. |
1107 | .IP "ev_tstamp repeat [read\-write]" 4 |
1183 | .IP "ev_tstamp repeat [read\-write]" 4 |
1108 | .IX Item "ev_tstamp repeat [read-write]" |
1184 | .IX Item "ev_tstamp repeat [read-write]" |
1109 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1185 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1110 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1186 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1111 | which is also when any modifications are taken into account. |
1187 | which is also when any modifications are taken into account. |
… | |
… | |
1384 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1460 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1385 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1461 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1386 | otherwise always forced to be at least one) and all the other fields of |
1462 | otherwise always forced to be at least one) and all the other fields of |
1387 | the stat buffer having unspecified contents. |
1463 | the stat buffer having unspecified contents. |
1388 | .PP |
1464 | .PP |
|
|
1465 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1466 | relative and your working directory changes, the behaviour is undefined. |
|
|
1467 | .PP |
1389 | Since there is no standard to do this, the portable implementation simply |
1468 | Since there is no standard to do this, the portable implementation simply |
1390 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
1469 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
1391 | can specify a recommended polling interval for this case. If you specify |
1470 | can specify a recommended polling interval for this case. If you specify |
1392 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1471 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1393 | unspecified default\fR value will be used (which you can expect to be around |
1472 | unspecified default\fR value will be used (which you can expect to be around |
… | |
… | |
1474 | \& ev_stat_start (loop, &passwd); |
1553 | \& ev_stat_start (loop, &passwd); |
1475 | .Ve |
1554 | .Ve |
1476 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1555 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1477 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1556 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1478 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1557 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1479 | Idle watchers trigger events when there are no other events are pending |
1558 | Idle watchers trigger events when no other events of the same or higher |
1480 | (prepare, check and other idle watchers do not count). That is, as long |
1559 | priority are pending (prepare, check and other idle watchers do not |
1481 | as your process is busy handling sockets or timeouts (or even signals, |
1560 | count). |
1482 | imagine) it will not be triggered. But when your process is idle all idle |
1561 | .PP |
1483 | watchers are being called again and again, once per event loop iteration \- |
1562 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1563 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1564 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1565 | are pending), the idle watchers are being called once per event loop |
1484 | until stopped, that is, or your process receives more events and becomes |
1566 | iteration \- until stopped, that is, or your process receives more events |
1485 | busy. |
1567 | and becomes busy again with higher priority stuff. |
1486 | .PP |
1568 | .PP |
1487 | The most noteworthy effect is that as long as any idle watchers are |
1569 | The most noteworthy effect is that as long as any idle watchers are |
1488 | active, the process will not block when waiting for new events. |
1570 | active, the process will not block when waiting for new events. |
1489 | .PP |
1571 | .PP |
1490 | Apart from keeping your process non-blocking (which is a useful |
1572 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1553 | are ready to run (it's actually more complicated: it only runs coroutines |
1635 | are ready to run (it's actually more complicated: it only runs coroutines |
1554 | with priority higher than or equal to the event loop and one coroutine |
1636 | with priority higher than or equal to the event loop and one coroutine |
1555 | of lower priority, but only once, using idle watchers to keep the event |
1637 | of lower priority, but only once, using idle watchers to keep the event |
1556 | loop from blocking if lower-priority coroutines are active, thus mapping |
1638 | loop from blocking if lower-priority coroutines are active, thus mapping |
1557 | low-priority coroutines to idle/background tasks). |
1639 | low-priority coroutines to idle/background tasks). |
|
|
1640 | .PP |
|
|
1641 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1642 | priority, to ensure that they are being run before any other watchers |
|
|
1643 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1644 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1645 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1646 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1647 | loops those other event loops might be in an unusable state until their |
|
|
1648 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1649 | others). |
1558 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1650 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1559 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1651 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1560 | .PD 0 |
1652 | .PD 0 |
1561 | .IP "ev_check_init (ev_check *, callback)" 4 |
1653 | .IP "ev_check_init (ev_check *, callback)" 4 |
1562 | .IX Item "ev_check_init (ev_check *, callback)" |
1654 | .IX Item "ev_check_init (ev_check *, callback)" |
1563 | .PD |
1655 | .PD |
1564 | Initialises and configures the prepare or check watcher \- they have no |
1656 | Initialises and configures the prepare or check watcher \- they have no |
1565 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1657 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1566 | macros, but using them is utterly, utterly and completely pointless. |
1658 | macros, but using them is utterly, utterly and completely pointless. |
1567 | .PP |
1659 | .PP |
1568 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1660 | There are a number of principal ways to embed other event loops or modules |
1569 | and a timeout watcher in a prepare handler, as required by libadns, and |
1661 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1662 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1663 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1664 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1665 | into the Glib event loop). |
|
|
1666 | .PP |
|
|
1667 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1570 | in a check watcher, destroy them and call into libadns. What follows is |
1668 | and in a check watcher, destroy them and call into libadns. What follows |
1571 | pseudo-code only of course: |
1669 | is pseudo-code only of course. This requires you to either use a low |
|
|
1670 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1671 | the callbacks for the IO/timeout watchers might not have been called yet. |
1572 | .PP |
1672 | .PP |
1573 | .Vb 2 |
1673 | .Vb 2 |
1574 | \& static ev_io iow [nfd]; |
1674 | \& static ev_io iow [nfd]; |
1575 | \& static ev_timer tw; |
1675 | \& static ev_timer tw; |
1576 | .Ve |
1676 | .Ve |
1577 | .PP |
1677 | .PP |
1578 | .Vb 9 |
1678 | .Vb 4 |
1579 | \& static void |
1679 | \& static void |
1580 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1680 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1581 | \& { |
1681 | \& { |
1582 | \& // set the relevant poll flags |
|
|
1583 | \& // could also call adns_processreadable etc. here |
|
|
1584 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1585 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1586 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1587 | \& } |
1682 | \& } |
1588 | .Ve |
1683 | .Ve |
1589 | .PP |
1684 | .PP |
1590 | .Vb 7 |
1685 | .Vb 8 |
1591 | \& // create io watchers for each fd and a timer before blocking |
1686 | \& // create io watchers for each fd and a timer before blocking |
1592 | \& static void |
1687 | \& static void |
1593 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1688 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1594 | \& { |
1689 | \& { |
1595 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1690 | \& int timeout = 3600000; |
|
|
1691 | \& struct pollfd fds [nfd]; |
1596 | \& // actual code will need to loop here and realloc etc. |
1692 | \& // actual code will need to loop here and realloc etc. |
1597 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1693 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1598 | .Ve |
1694 | .Ve |
1599 | .PP |
1695 | .PP |
1600 | .Vb 3 |
1696 | .Vb 3 |
… | |
… | |
1602 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1698 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1603 | \& ev_timer_start (loop, &tw); |
1699 | \& ev_timer_start (loop, &tw); |
1604 | .Ve |
1700 | .Ve |
1605 | .PP |
1701 | .PP |
1606 | .Vb 6 |
1702 | .Vb 6 |
1607 | \& // create on ev_io per pollfd |
1703 | \& // create one ev_io per pollfd |
1608 | \& for (int i = 0; i < nfd; ++i) |
1704 | \& for (int i = 0; i < nfd; ++i) |
1609 | \& { |
1705 | \& { |
1610 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1706 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1611 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1707 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1612 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1708 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1613 | .Ve |
1709 | .Ve |
1614 | .PP |
1710 | .PP |
1615 | .Vb 5 |
1711 | .Vb 4 |
1616 | \& fds [i].revents = 0; |
1712 | \& fds [i].revents = 0; |
1617 | \& iow [i].data = fds + i; |
|
|
1618 | \& ev_io_start (loop, iow + i); |
1713 | \& ev_io_start (loop, iow + i); |
1619 | \& } |
1714 | \& } |
1620 | \& } |
1715 | \& } |
1621 | .Ve |
1716 | .Ve |
1622 | .PP |
1717 | .PP |
… | |
… | |
1626 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1721 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1627 | \& { |
1722 | \& { |
1628 | \& ev_timer_stop (loop, &tw); |
1723 | \& ev_timer_stop (loop, &tw); |
1629 | .Ve |
1724 | .Ve |
1630 | .PP |
1725 | .PP |
1631 | .Vb 2 |
1726 | .Vb 8 |
1632 | \& for (int i = 0; i < nfd; ++i) |
1727 | \& for (int i = 0; i < nfd; ++i) |
|
|
1728 | \& { |
|
|
1729 | \& // set the relevant poll flags |
|
|
1730 | \& // could also call adns_processreadable etc. here |
|
|
1731 | \& struct pollfd *fd = fds + i; |
|
|
1732 | \& int revents = ev_clear_pending (iow + i); |
|
|
1733 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1734 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1735 | .Ve |
|
|
1736 | .PP |
|
|
1737 | .Vb 3 |
|
|
1738 | \& // now stop the watcher |
1633 | \& ev_io_stop (loop, iow + i); |
1739 | \& ev_io_stop (loop, iow + i); |
|
|
1740 | \& } |
1634 | .Ve |
1741 | .Ve |
1635 | .PP |
1742 | .PP |
1636 | .Vb 2 |
1743 | .Vb 2 |
1637 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1744 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1745 | \& } |
|
|
1746 | .Ve |
|
|
1747 | .PP |
|
|
1748 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1749 | in the prepare watcher and would dispose of the check watcher. |
|
|
1750 | .PP |
|
|
1751 | Method 3: If the module to be embedded supports explicit event |
|
|
1752 | notification (adns does), you can also make use of the actual watcher |
|
|
1753 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1754 | .PP |
|
|
1755 | .Vb 5 |
|
|
1756 | \& static void |
|
|
1757 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1758 | \& { |
|
|
1759 | \& adns_state ads = (adns_state)w->data; |
|
|
1760 | \& update_now (EV_A); |
|
|
1761 | .Ve |
|
|
1762 | .PP |
|
|
1763 | .Vb 2 |
|
|
1764 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1765 | \& } |
|
|
1766 | .Ve |
|
|
1767 | .PP |
|
|
1768 | .Vb 5 |
|
|
1769 | \& static void |
|
|
1770 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1771 | \& { |
|
|
1772 | \& adns_state ads = (adns_state)w->data; |
|
|
1773 | \& update_now (EV_A); |
|
|
1774 | .Ve |
|
|
1775 | .PP |
|
|
1776 | .Vb 3 |
|
|
1777 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1778 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1779 | \& } |
|
|
1780 | .Ve |
|
|
1781 | .PP |
|
|
1782 | .Vb 1 |
|
|
1783 | \& // do not ever call adns_afterpoll |
|
|
1784 | .Ve |
|
|
1785 | .PP |
|
|
1786 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1787 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1788 | their poll function. The drawback with this solution is that the main |
|
|
1789 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1790 | this. |
|
|
1791 | .PP |
|
|
1792 | .Vb 4 |
|
|
1793 | \& static gint |
|
|
1794 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1795 | \& { |
|
|
1796 | \& int got_events = 0; |
|
|
1797 | .Ve |
|
|
1798 | .PP |
|
|
1799 | .Vb 2 |
|
|
1800 | \& for (n = 0; n < nfds; ++n) |
|
|
1801 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1802 | .Ve |
|
|
1803 | .PP |
|
|
1804 | .Vb 2 |
|
|
1805 | \& if (timeout >= 0) |
|
|
1806 | \& // create/start timer |
|
|
1807 | .Ve |
|
|
1808 | .PP |
|
|
1809 | .Vb 2 |
|
|
1810 | \& // poll |
|
|
1811 | \& ev_loop (EV_A_ 0); |
|
|
1812 | .Ve |
|
|
1813 | .PP |
|
|
1814 | .Vb 3 |
|
|
1815 | \& // stop timer again |
|
|
1816 | \& if (timeout >= 0) |
|
|
1817 | \& ev_timer_stop (EV_A_ &to); |
|
|
1818 | .Ve |
|
|
1819 | .PP |
|
|
1820 | .Vb 3 |
|
|
1821 | \& // stop io watchers again - their callbacks should have set |
|
|
1822 | \& for (n = 0; n < nfds; ++n) |
|
|
1823 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1824 | .Ve |
|
|
1825 | .PP |
|
|
1826 | .Vb 2 |
|
|
1827 | \& return got_events; |
1638 | \& } |
1828 | \& } |
1639 | .Ve |
1829 | .Ve |
1640 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1830 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1641 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1831 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1642 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1832 | .IX Subsection "ev_embed - when one backend isn't enough..." |
… | |
… | |
1826 | .PP |
2016 | .PP |
1827 | .Vb 1 |
2017 | .Vb 1 |
1828 | \& #include <ev++.h> |
2018 | \& #include <ev++.h> |
1829 | .Ve |
2019 | .Ve |
1830 | .PP |
2020 | .PP |
1831 | (it is not installed by default). This automatically includes \fIev.h\fR |
2021 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1832 | and puts all of its definitions (many of them macros) into the global |
2022 | of them macros) into the global namespace. All \*(C+ specific things are |
1833 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2023 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2024 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1834 | .PP |
2025 | .PP |
1835 | It should support all the same embedding options as \fIev.h\fR, most notably |
2026 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1836 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2027 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2028 | that the watcher is associated with (or no additional members at all if |
|
|
2029 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2030 | .PP |
|
|
2031 | Currently, functions, and static and non-static member functions can be |
|
|
2032 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2033 | need one additional pointer for context. If you need support for other |
|
|
2034 | types of functors please contact the author (preferably after implementing |
|
|
2035 | it). |
1837 | .PP |
2036 | .PP |
1838 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2037 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1839 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2038 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1840 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2039 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1841 | .IX Item "ev::READ, ev::WRITE etc." |
2040 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1853 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2052 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1854 | defines by many implementations. |
2053 | defines by many implementations. |
1855 | .Sp |
2054 | .Sp |
1856 | All of those classes have these methods: |
2055 | All of those classes have these methods: |
1857 | .RS 4 |
2056 | .RS 4 |
1858 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2057 | .IP "ev::TYPE::TYPE ()" 4 |
1859 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2058 | .IX Item "ev::TYPE::TYPE ()" |
1860 | .PD 0 |
2059 | .PD 0 |
1861 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2060 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1862 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2061 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1863 | .IP "ev::TYPE::~TYPE" 4 |
2062 | .IP "ev::TYPE::~TYPE" 4 |
1864 | .IX Item "ev::TYPE::~TYPE" |
2063 | .IX Item "ev::TYPE::~TYPE" |
1865 | .PD |
2064 | .PD |
1866 | The constructor takes a pointer to an object and a method pointer to |
2065 | The constructor (optionally) takes an event loop to associate the watcher |
1867 | the event handler callback to call in this class. The constructor calls |
2066 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1868 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2067 | .Sp |
1869 | before starting it. If you do not specify a loop then the constructor |
2068 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1870 | automatically associates the default loop with this watcher. |
2069 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2070 | .Sp |
|
|
2071 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2072 | method to set a callback before you can start the watcher. |
|
|
2073 | .Sp |
|
|
2074 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2075 | not allow explicit template arguments for constructors). |
1871 | .Sp |
2076 | .Sp |
1872 | The destructor automatically stops the watcher if it is active. |
2077 | The destructor automatically stops the watcher if it is active. |
|
|
2078 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2079 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2080 | This method sets the callback method to call. The method has to have a |
|
|
2081 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2082 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2083 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2084 | .Sp |
|
|
2085 | This method synthesizes efficient thunking code to call your method from |
|
|
2086 | the C callback that libev requires. If your compiler can inline your |
|
|
2087 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2088 | your compiler is good :), then the method will be fully inlined into the |
|
|
2089 | thunking function, making it as fast as a direct C callback. |
|
|
2090 | .Sp |
|
|
2091 | Example: simple class declaration and watcher initialisation |
|
|
2092 | .Sp |
|
|
2093 | .Vb 4 |
|
|
2094 | \& struct myclass |
|
|
2095 | \& { |
|
|
2096 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2097 | \& } |
|
|
2098 | .Ve |
|
|
2099 | .Sp |
|
|
2100 | .Vb 3 |
|
|
2101 | \& myclass obj; |
|
|
2102 | \& ev::io iow; |
|
|
2103 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2104 | .Ve |
|
|
2105 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2106 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2107 | Also sets a callback, but uses a static method or plain function as |
|
|
2108 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2109 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2110 | .Sp |
|
|
2111 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2112 | .Sp |
|
|
2113 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2114 | .Sp |
|
|
2115 | Example: |
|
|
2116 | .Sp |
|
|
2117 | .Vb 2 |
|
|
2118 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2119 | \& iow.set <io_cb> (); |
|
|
2120 | .Ve |
1873 | .IP "w\->set (struct ev_loop *)" 4 |
2121 | .IP "w\->set (struct ev_loop *)" 4 |
1874 | .IX Item "w->set (struct ev_loop *)" |
2122 | .IX Item "w->set (struct ev_loop *)" |
1875 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2123 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1876 | do this when the watcher is inactive (and not pending either). |
2124 | do this when the watcher is inactive (and not pending either). |
1877 | .IP "w\->set ([args])" 4 |
2125 | .IP "w\->set ([args])" 4 |
1878 | .IX Item "w->set ([args])" |
2126 | .IX Item "w->set ([args])" |
1879 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2127 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1880 | called at least once. Unlike the C counterpart, an active watcher gets |
2128 | called at least once. Unlike the C counterpart, an active watcher gets |
1881 | automatically stopped and restarted. |
2129 | automatically stopped and restarted when reconfiguring it with this |
|
|
2130 | method. |
1882 | .IP "w\->start ()" 4 |
2131 | .IP "w\->start ()" 4 |
1883 | .IX Item "w->start ()" |
2132 | .IX Item "w->start ()" |
1884 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2133 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1885 | constructor already takes the loop. |
2134 | constructor already stores the event loop. |
1886 | .IP "w\->stop ()" 4 |
2135 | .IP "w\->stop ()" 4 |
1887 | .IX Item "w->stop ()" |
2136 | .IX Item "w->stop ()" |
1888 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2137 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1889 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2138 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1890 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2139 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1916 | .Vb 2 |
2165 | .Vb 2 |
1917 | \& myclass (); |
2166 | \& myclass (); |
1918 | \& } |
2167 | \& } |
1919 | .Ve |
2168 | .Ve |
1920 | .PP |
2169 | .PP |
1921 | .Vb 6 |
2170 | .Vb 4 |
1922 | \& myclass::myclass (int fd) |
2171 | \& myclass::myclass (int fd) |
1923 | \& : io (this, &myclass::io_cb), |
|
|
1924 | \& idle (this, &myclass::idle_cb) |
|
|
1925 | \& { |
2172 | \& { |
|
|
2173 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2174 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2175 | .Ve |
|
|
2176 | .PP |
|
|
2177 | .Vb 2 |
1926 | \& io.start (fd, ev::READ); |
2178 | \& io.start (fd, ev::READ); |
1927 | \& } |
2179 | \& } |
1928 | .Ve |
2180 | .Ve |
1929 | .SH "MACRO MAGIC" |
2181 | .SH "MACRO MAGIC" |
1930 | .IX Header "MACRO MAGIC" |
2182 | .IX Header "MACRO MAGIC" |
1931 | Libev can be compiled with a variety of options, the most fundemantal is |
2183 | Libev can be compiled with a variety of options, the most fundemantal is |
1932 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
2184 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
1933 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2185 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1934 | .PP |
2186 | .PP |
1935 | To make it easier to write programs that cope with either variant, the |
2187 | To make it easier to write programs that cope with either variant, the |
1936 | following macros are defined: |
2188 | following macros are defined: |
1937 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2189 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
… | |
… | |
1972 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
2224 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1973 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2225 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1974 | Similar to the other two macros, this gives you the value of the default |
2226 | Similar to the other two macros, this gives you the value of the default |
1975 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
2227 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
1976 | .PP |
2228 | .PP |
1977 | Example: Declare and initialise a check watcher, working regardless of |
2229 | Example: Declare and initialise a check watcher, utilising the above |
1978 | wether multiple loops are supported or not. |
2230 | macros so it will work regardless of whether multiple loops are supported |
|
|
2231 | or not. |
1979 | .PP |
2232 | .PP |
1980 | .Vb 5 |
2233 | .Vb 5 |
1981 | \& static void |
2234 | \& static void |
1982 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2235 | \& check_cb (EV_P_ ev_timer *w, int revents) |
1983 | \& { |
2236 | \& { |
… | |
… | |
2046 | .Vb 1 |
2299 | .Vb 1 |
2047 | \& ev_win32.c required on win32 platforms only |
2300 | \& ev_win32.c required on win32 platforms only |
2048 | .Ve |
2301 | .Ve |
2049 | .PP |
2302 | .PP |
2050 | .Vb 5 |
2303 | .Vb 5 |
2051 | \& ev_select.c only when select backend is enabled (which is by default) |
2304 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
2052 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2305 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2053 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2306 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2054 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2307 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2055 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2308 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2056 | .Ve |
2309 | .Ve |
… | |
… | |
2209 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2462 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2210 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2463 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2211 | additional independent event loops. Otherwise there will be no support |
2464 | additional independent event loops. Otherwise there will be no support |
2212 | for multiple event loops and there is no first event loop pointer |
2465 | for multiple event loops and there is no first event loop pointer |
2213 | argument. Instead, all functions act on the single default loop. |
2466 | argument. Instead, all functions act on the single default loop. |
|
|
2467 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2468 | .IX Item "EV_MINPRI" |
|
|
2469 | .PD 0 |
|
|
2470 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2471 | .IX Item "EV_MAXPRI" |
|
|
2472 | .PD |
|
|
2473 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2474 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2475 | provide for more priorities by overriding those symbols (usually defined |
|
|
2476 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2477 | .Sp |
|
|
2478 | When doing priority-based operations, libev usually has to linearly search |
|
|
2479 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2480 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2481 | fine. |
|
|
2482 | .Sp |
|
|
2483 | If your embedding app does not need any priorities, defining these both to |
|
|
2484 | \&\f(CW0\fR will save some memory and cpu. |
2214 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2485 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2215 | .IX Item "EV_PERIODIC_ENABLE" |
2486 | .IX Item "EV_PERIODIC_ENABLE" |
2216 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2487 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2488 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2489 | code. |
|
|
2490 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2491 | .IX Item "EV_IDLE_ENABLE" |
|
|
2492 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
2217 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2493 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2218 | code. |
2494 | code. |
2219 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2495 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2220 | .IX Item "EV_EMBED_ENABLE" |
2496 | .IX Item "EV_EMBED_ENABLE" |
2221 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2497 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
… | |
… | |
2283 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2559 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2284 | will be compiled. It is pretty complex because it provides its own header |
2560 | will be compiled. It is pretty complex because it provides its own header |
2285 | file. |
2561 | file. |
2286 | .Sp |
2562 | .Sp |
2287 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2563 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2288 | that everybody includes and which overrides some autoconf choices: |
2564 | that everybody includes and which overrides some configure choices: |
2289 | .Sp |
2565 | .Sp |
2290 | .Vb 4 |
2566 | .Vb 9 |
|
|
2567 | \& #define EV_MINIMAL 1 |
2291 | \& #define EV_USE_POLL 0 |
2568 | \& #define EV_USE_POLL 0 |
2292 | \& #define EV_MULTIPLICITY 0 |
2569 | \& #define EV_MULTIPLICITY 0 |
2293 | \& #define EV_PERIODICS 0 |
2570 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2571 | \& #define EV_STAT_ENABLE 0 |
|
|
2572 | \& #define EV_FORK_ENABLE 0 |
2294 | \& #define EV_CONFIG_H <config.h> |
2573 | \& #define EV_CONFIG_H <config.h> |
|
|
2574 | \& #define EV_MINPRI 0 |
|
|
2575 | \& #define EV_MAXPRI 0 |
2295 | .Ve |
2576 | .Ve |
2296 | .Sp |
2577 | .Sp |
2297 | .Vb 1 |
2578 | .Vb 1 |
2298 | \& #include "ev++.h" |
2579 | \& #include "ev++.h" |
2299 | .Ve |
2580 | .Ve |
… | |
… | |
2307 | .SH "COMPLEXITIES" |
2588 | .SH "COMPLEXITIES" |
2308 | .IX Header "COMPLEXITIES" |
2589 | .IX Header "COMPLEXITIES" |
2309 | In this section the complexities of (many of) the algorithms used inside |
2590 | In this section the complexities of (many of) the algorithms used inside |
2310 | libev will be explained. For complexity discussions about backends see the |
2591 | libev will be explained. For complexity discussions about backends see the |
2311 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2592 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2593 | .Sp |
|
|
2594 | All of the following are about amortised time: If an array needs to be |
|
|
2595 | extended, libev needs to realloc and move the whole array, but this |
|
|
2596 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2597 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2598 | it is much faster and asymptotically approaches constant time. |
2312 | .RS 4 |
2599 | .RS 4 |
2313 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2600 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2314 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2601 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2315 | .PD 0 |
2602 | This means that, when you have a watcher that triggers in one hour and |
|
|
2603 | there are 100 watchers that would trigger before that then inserting will |
|
|
2604 | have to skip those 100 watchers. |
2316 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2605 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2317 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2606 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2607 | That means that for changing a timer costs less than removing/adding them |
|
|
2608 | as only the relative motion in the event queue has to be paid for. |
2318 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2609 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2319 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2610 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2320 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2611 | These just add the watcher into an array or at the head of a list. |
2321 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2612 | =item Stopping check/prepare/idle watchers: O(1) |
2322 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2613 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2323 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2614 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2615 | These watchers are stored in lists then need to be walked to find the |
|
|
2616 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2617 | have many watchers waiting for the same fd or signal). |
2324 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2618 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2325 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2619 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2620 | .PD 0 |
2326 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2621 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2327 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2622 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2623 | .PD |
|
|
2624 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2625 | libev to recalculate its status (and possibly tell the kernel). |
2328 | .IP "Activating one watcher: O(1)" 4 |
2626 | .IP "Activating one watcher: O(1)" 4 |
2329 | .IX Item "Activating one watcher: O(1)" |
2627 | .IX Item "Activating one watcher: O(1)" |
|
|
2628 | .PD 0 |
|
|
2629 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2630 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2631 | .PD |
|
|
2632 | Priorities are implemented by allocating some space for each |
|
|
2633 | priority. When doing priority-based operations, libev usually has to |
|
|
2634 | linearly search all the priorities. |
2330 | .RE |
2635 | .RE |
2331 | .RS 4 |
2636 | .RS 4 |
2332 | .PD |
|
|
2333 | .SH "AUTHOR" |
2637 | .SH "AUTHOR" |
2334 | .IX Header "AUTHOR" |
2638 | .IX Header "AUTHOR" |
2335 | Marc Lehmann <libev@schmorp.de>. |
2639 | Marc Lehmann <libev@schmorp.de>. |