… | |
… | |
47 | |
47 | |
48 | return 0; |
48 | return 0; |
49 | } |
49 | } |
50 | |
50 | |
51 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
|
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52 | |
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53 | The newest version of this document is also available as a html-formatted |
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54 | web page you might find easier to navigate when reading it for the first |
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55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
52 | |
56 | |
53 | Libev is an event loop: you register interest in certain events (such as a |
57 | Libev is an event loop: you register interest in certain events (such as a |
54 | file descriptor being readable or a timeout occuring), and it will manage |
58 | file descriptor being readable or a timeout occuring), and it will manage |
55 | these event sources and provide your program with events. |
59 | these event sources and provide your program with events. |
56 | |
60 | |
… | |
… | |
63 | details of the event, and then hand it over to libev by I<starting> the |
67 | details of the event, and then hand it over to libev by I<starting> the |
64 | watcher. |
68 | watcher. |
65 | |
69 | |
66 | =head1 FEATURES |
70 | =head1 FEATURES |
67 | |
71 | |
68 | Libev supports C<select>, C<poll>, the linux-specific C<epoll>, the |
72 | Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the |
69 | bsd-specific C<kqueue> and the solaris-specific event port mechanisms |
73 | BSD-specific C<kqueue> and the Solaris-specific event port mechanisms |
70 | for file descriptor events (C<ev_io>), relative timers (C<ev_timer>), |
74 | for file descriptor events (C<ev_io>), the Linux C<inotify> interface |
|
|
75 | (for C<ev_stat>), relative timers (C<ev_timer>), absolute timers |
71 | absolute timers with customised rescheduling (C<ev_periodic>), synchronous |
76 | with customised rescheduling (C<ev_periodic>), synchronous signals |
72 | signals (C<ev_signal>), process status change events (C<ev_child>), and |
77 | (C<ev_signal>), process status change events (C<ev_child>), and event |
73 | event watchers dealing with the event loop mechanism itself (C<ev_idle>, |
78 | watchers dealing with the event loop mechanism itself (C<ev_idle>, |
74 | C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as |
79 | C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as |
75 | file watchers (C<ev_stat>) and even limited support for fork events |
80 | file watchers (C<ev_stat>) and even limited support for fork events |
76 | (C<ev_fork>). |
81 | (C<ev_fork>). |
77 | |
82 | |
78 | It also is quite fast (see this |
83 | It also is quite fast (see this |
… | |
… | |
162 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
167 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
163 | recommended ones. |
168 | recommended ones. |
164 | |
169 | |
165 | See the description of C<ev_embed> watchers for more info. |
170 | See the description of C<ev_embed> watchers for more info. |
166 | |
171 | |
167 | =item ev_set_allocator (void *(*cb)(void *ptr, size_t size)) |
172 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
168 | |
173 | |
169 | Sets the allocation function to use (the prototype and semantics are |
174 | Sets the allocation function to use (the prototype is similar - the |
170 | identical to the realloc C function). It is used to allocate and free |
175 | semantics is identical - to the realloc C function). It is used to |
171 | memory (no surprises here). If it returns zero when memory needs to be |
176 | allocate and free memory (no surprises here). If it returns zero when |
172 | allocated, the library might abort or take some potentially destructive |
177 | memory needs to be allocated, the library might abort or take some |
173 | action. The default is your system realloc function. |
178 | potentially destructive action. The default is your system realloc |
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|
179 | function. |
174 | |
180 | |
175 | You could override this function in high-availability programs to, say, |
181 | You could override this function in high-availability programs to, say, |
176 | free some memory if it cannot allocate memory, to use a special allocator, |
182 | free some memory if it cannot allocate memory, to use a special allocator, |
177 | or even to sleep a while and retry until some memory is available. |
183 | or even to sleep a while and retry until some memory is available. |
178 | |
184 | |
… | |
… | |
264 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
270 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
265 | override the flags completely if it is found in the environment. This is |
271 | override the flags completely if it is found in the environment. This is |
266 | useful to try out specific backends to test their performance, or to work |
272 | useful to try out specific backends to test their performance, or to work |
267 | around bugs. |
273 | around bugs. |
268 | |
274 | |
|
|
275 | =item C<EVFLAG_FORKCHECK> |
|
|
276 | |
|
|
277 | Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after |
|
|
278 | a fork, you can also make libev check for a fork in each iteration by |
|
|
279 | enabling this flag. |
|
|
280 | |
|
|
281 | This works by calling C<getpid ()> on every iteration of the loop, |
|
|
282 | and thus this might slow down your event loop if you do a lot of loop |
|
|
283 | iterations and little real work, but is usually not noticeable (on my |
|
|
284 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
|
|
285 | without a syscall and thus I<very> fast, but my Linux system also has |
|
|
286 | C<pthread_atfork> which is even faster). |
|
|
287 | |
|
|
288 | The big advantage of this flag is that you can forget about fork (and |
|
|
289 | forget about forgetting to tell libev about forking) when you use this |
|
|
290 | flag. |
|
|
291 | |
|
|
292 | This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS> |
|
|
293 | environment variable. |
|
|
294 | |
269 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
295 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
270 | |
296 | |
271 | This is your standard select(2) backend. Not I<completely> standard, as |
297 | This is your standard select(2) backend. Not I<completely> standard, as |
272 | libev tries to roll its own fd_set with no limits on the number of fds, |
298 | libev tries to roll its own fd_set with no limits on the number of fds, |
273 | but if that fails, expect a fairly low limit on the number of fds when |
299 | but if that fails, expect a fairly low limit on the number of fds when |
… | |
… | |
407 | =item ev_loop_fork (loop) |
433 | =item ev_loop_fork (loop) |
408 | |
434 | |
409 | Like C<ev_default_fork>, but acts on an event loop created by |
435 | Like C<ev_default_fork>, but acts on an event loop created by |
410 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
436 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
411 | after fork, and how you do this is entirely your own problem. |
437 | after fork, and how you do this is entirely your own problem. |
|
|
438 | |
|
|
439 | =item unsigned int ev_loop_count (loop) |
|
|
440 | |
|
|
441 | Returns the count of loop iterations for the loop, which is identical to |
|
|
442 | the number of times libev did poll for new events. It starts at C<0> and |
|
|
443 | happily wraps around with enough iterations. |
|
|
444 | |
|
|
445 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
446 | "ticks" the number of loop iterations), as it roughly corresponds with |
|
|
447 | C<ev_prepare> and C<ev_check> calls. |
412 | |
448 | |
413 | =item unsigned int ev_backend (loop) |
449 | =item unsigned int ev_backend (loop) |
414 | |
450 | |
415 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
451 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
416 | use. |
452 | use. |
… | |
… | |
700 | =item bool ev_is_pending (ev_TYPE *watcher) |
736 | =item bool ev_is_pending (ev_TYPE *watcher) |
701 | |
737 | |
702 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
738 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
703 | events but its callback has not yet been invoked). As long as a watcher |
739 | events but its callback has not yet been invoked). As long as a watcher |
704 | is pending (but not active) you must not call an init function on it (but |
740 | is pending (but not active) you must not call an init function on it (but |
705 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
741 | C<ev_TYPE_set> is safe), you must not change its priority, and you must |
706 | libev (e.g. you cnanot C<free ()> it). |
742 | make sure the watcher is available to libev (e.g. you cannot C<free ()> |
|
|
743 | it). |
707 | |
744 | |
708 | =item callback ev_cb (ev_TYPE *watcher) |
745 | =item callback ev_cb (ev_TYPE *watcher) |
709 | |
746 | |
710 | Returns the callback currently set on the watcher. |
747 | Returns the callback currently set on the watcher. |
711 | |
748 | |
712 | =item ev_cb_set (ev_TYPE *watcher, callback) |
749 | =item ev_cb_set (ev_TYPE *watcher, callback) |
713 | |
750 | |
714 | Change the callback. You can change the callback at virtually any time |
751 | Change the callback. You can change the callback at virtually any time |
715 | (modulo threads). |
752 | (modulo threads). |
|
|
753 | |
|
|
754 | =item ev_set_priority (ev_TYPE *watcher, priority) |
|
|
755 | |
|
|
756 | =item int ev_priority (ev_TYPE *watcher) |
|
|
757 | |
|
|
758 | Set and query the priority of the watcher. The priority is a small |
|
|
759 | integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> |
|
|
760 | (default: C<-2>). Pending watchers with higher priority will be invoked |
|
|
761 | before watchers with lower priority, but priority will not keep watchers |
|
|
762 | from being executed (except for C<ev_idle> watchers). |
|
|
763 | |
|
|
764 | This means that priorities are I<only> used for ordering callback |
|
|
765 | invocation after new events have been received. This is useful, for |
|
|
766 | example, to reduce latency after idling, or more often, to bind two |
|
|
767 | watchers on the same event and make sure one is called first. |
|
|
768 | |
|
|
769 | If you need to suppress invocation when higher priority events are pending |
|
|
770 | you need to look at C<ev_idle> watchers, which provide this functionality. |
|
|
771 | |
|
|
772 | You I<must not> change the priority of a watcher as long as it is active or |
|
|
773 | pending. |
|
|
774 | |
|
|
775 | The default priority used by watchers when no priority has been set is |
|
|
776 | always C<0>, which is supposed to not be too high and not be too low :). |
|
|
777 | |
|
|
778 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
|
|
779 | fine, as long as you do not mind that the priority value you query might |
|
|
780 | or might not have been adjusted to be within valid range. |
|
|
781 | |
|
|
782 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
|
|
783 | |
|
|
784 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
|
|
785 | C<loop> nor C<revents> need to be valid as long as the watcher callback |
|
|
786 | can deal with that fact. |
|
|
787 | |
|
|
788 | =item int ev_clear_pending (loop, ev_TYPE *watcher) |
|
|
789 | |
|
|
790 | If the watcher is pending, this function returns clears its pending status |
|
|
791 | and returns its C<revents> bitset (as if its callback was invoked). If the |
|
|
792 | watcher isn't pending it does nothing and returns C<0>. |
716 | |
793 | |
717 | =back |
794 | =back |
718 | |
795 | |
719 | |
796 | |
720 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
797 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
826 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
903 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
827 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
904 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
828 | |
905 | |
829 | If you cannot run the fd in non-blocking mode (for example you should not |
906 | If you cannot run the fd in non-blocking mode (for example you should not |
830 | play around with an Xlib connection), then you have to seperately re-test |
907 | play around with an Xlib connection), then you have to seperately re-test |
831 | wether a file descriptor is really ready with a known-to-be good interface |
908 | whether a file descriptor is really ready with a known-to-be good interface |
832 | such as poll (fortunately in our Xlib example, Xlib already does this on |
909 | such as poll (fortunately in our Xlib example, Xlib already does this on |
833 | its own, so its quite safe to use). |
910 | its own, so its quite safe to use). |
834 | |
911 | |
835 | =over 4 |
912 | =over 4 |
836 | |
913 | |
… | |
… | |
914 | =item ev_timer_again (loop) |
991 | =item ev_timer_again (loop) |
915 | |
992 | |
916 | This will act as if the timer timed out and restart it again if it is |
993 | This will act as if the timer timed out and restart it again if it is |
917 | repeating. The exact semantics are: |
994 | repeating. The exact semantics are: |
918 | |
995 | |
|
|
996 | If the timer is pending, its pending status is cleared. |
|
|
997 | |
919 | If the timer is started but nonrepeating, stop it. |
998 | If the timer is started but nonrepeating, stop it (as if it timed out). |
920 | |
999 | |
921 | If the timer is repeating, either start it if necessary (with the repeat |
1000 | If the timer is repeating, either start it if necessary (with the |
922 | value), or reset the running timer to the repeat value. |
1001 | C<repeat> value), or reset the running timer to the C<repeat> value. |
923 | |
1002 | |
924 | This sounds a bit complicated, but here is a useful and typical |
1003 | This sounds a bit complicated, but here is a useful and typical |
925 | example: Imagine you have a tcp connection and you want a so-called |
1004 | example: Imagine you have a tcp connection and you want a so-called idle |
926 | idle timeout, that is, you want to be called when there have been, |
1005 | timeout, that is, you want to be called when there have been, say, 60 |
927 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1006 | seconds of inactivity on the socket. The easiest way to do this is to |
928 | this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling |
1007 | configure an C<ev_timer> with a C<repeat> value of C<60> and then call |
929 | C<ev_timer_again> each time you successfully read or write some data. If |
1008 | C<ev_timer_again> each time you successfully read or write some data. If |
930 | you go into an idle state where you do not expect data to travel on the |
1009 | you go into an idle state where you do not expect data to travel on the |
931 | socket, you can stop the timer, and again will automatically restart it if |
1010 | socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will |
932 | need be. |
1011 | automatically restart it if need be. |
933 | |
1012 | |
934 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
1013 | That means you can ignore the C<after> value and C<ev_timer_start> |
935 | and only ever use the C<repeat> value: |
1014 | altogether and only ever use the C<repeat> value and C<ev_timer_again>: |
936 | |
1015 | |
937 | ev_timer_init (timer, callback, 0., 5.); |
1016 | ev_timer_init (timer, callback, 0., 5.); |
938 | ev_timer_again (loop, timer); |
1017 | ev_timer_again (loop, timer); |
939 | ... |
1018 | ... |
940 | timer->again = 17.; |
1019 | timer->again = 17.; |
941 | ev_timer_again (loop, timer); |
1020 | ev_timer_again (loop, timer); |
942 | ... |
1021 | ... |
943 | timer->again = 10.; |
1022 | timer->again = 10.; |
944 | ev_timer_again (loop, timer); |
1023 | ev_timer_again (loop, timer); |
945 | |
1024 | |
946 | This is more efficient then stopping/starting the timer eahc time you want |
1025 | This is more slightly efficient then stopping/starting the timer each time |
947 | to modify its timeout value. |
1026 | you want to modify its timeout value. |
948 | |
1027 | |
949 | =item ev_tstamp repeat [read-write] |
1028 | =item ev_tstamp repeat [read-write] |
950 | |
1029 | |
951 | The current C<repeat> value. Will be used each time the watcher times out |
1030 | The current C<repeat> value. Will be used each time the watcher times out |
952 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1031 | or C<ev_timer_again> is called and determines the next timeout (if any), |
… | |
… | |
1221 | not exist" is a status change like any other. The condition "path does |
1300 | not exist" is a status change like any other. The condition "path does |
1222 | not exist" is signified by the C<st_nlink> field being zero (which is |
1301 | not exist" is signified by the C<st_nlink> field being zero (which is |
1223 | otherwise always forced to be at least one) and all the other fields of |
1302 | otherwise always forced to be at least one) and all the other fields of |
1224 | the stat buffer having unspecified contents. |
1303 | the stat buffer having unspecified contents. |
1225 | |
1304 | |
|
|
1305 | The path I<should> be absolute and I<must not> end in a slash. If it is |
|
|
1306 | relative and your working directory changes, the behaviour is undefined. |
|
|
1307 | |
1226 | Since there is no standard to do this, the portable implementation simply |
1308 | Since there is no standard to do this, the portable implementation simply |
1227 | calls C<stat (2)> regulalry on the path to see if it changed somehow. You |
1309 | calls C<stat (2)> regularly on the path to see if it changed somehow. You |
1228 | can specify a recommended polling interval for this case. If you specify |
1310 | can specify a recommended polling interval for this case. If you specify |
1229 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1311 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1230 | unspecified default> value will be used (which you can expect to be around |
1312 | unspecified default> value will be used (which you can expect to be around |
1231 | five seconds, although this might change dynamically). Libev will also |
1313 | five seconds, although this might change dynamically). Libev will also |
1232 | impose a minimum interval which is currently around C<0.1>, but thats |
1314 | impose a minimum interval which is currently around C<0.1>, but thats |
… | |
… | |
1234 | |
1316 | |
1235 | This watcher type is not meant for massive numbers of stat watchers, |
1317 | This watcher type is not meant for massive numbers of stat watchers, |
1236 | as even with OS-supported change notifications, this can be |
1318 | as even with OS-supported change notifications, this can be |
1237 | resource-intensive. |
1319 | resource-intensive. |
1238 | |
1320 | |
1239 | At the time of this writing, no specific OS backends are implemented, but |
1321 | At the time of this writing, only the Linux inotify interface is |
1240 | if demand increases, at least a kqueue and inotify backend will be added. |
1322 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1323 | reader). Inotify will be used to give hints only and should not change the |
|
|
1324 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
|
|
1325 | to fall back to regular polling again even with inotify, but changes are |
|
|
1326 | usually detected immediately, and if the file exists there will be no |
|
|
1327 | polling. |
1241 | |
1328 | |
1242 | =over 4 |
1329 | =over 4 |
1243 | |
1330 | |
1244 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1331 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1245 | |
1332 | |
… | |
… | |
1309 | ev_stat_start (loop, &passwd); |
1396 | ev_stat_start (loop, &passwd); |
1310 | |
1397 | |
1311 | |
1398 | |
1312 | =head2 C<ev_idle> - when you've got nothing better to do... |
1399 | =head2 C<ev_idle> - when you've got nothing better to do... |
1313 | |
1400 | |
1314 | Idle watchers trigger events when there are no other events are pending |
1401 | Idle watchers trigger events when no other events of the same or higher |
1315 | (prepare, check and other idle watchers do not count). That is, as long |
1402 | priority are pending (prepare, check and other idle watchers do not |
1316 | as your process is busy handling sockets or timeouts (or even signals, |
1403 | count). |
1317 | imagine) it will not be triggered. But when your process is idle all idle |
1404 | |
1318 | watchers are being called again and again, once per event loop iteration - |
1405 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1406 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1407 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1408 | are pending), the idle watchers are being called once per event loop |
1319 | until stopped, that is, or your process receives more events and becomes |
1409 | iteration - until stopped, that is, or your process receives more events |
1320 | busy. |
1410 | and becomes busy again with higher priority stuff. |
1321 | |
1411 | |
1322 | The most noteworthy effect is that as long as any idle watchers are |
1412 | The most noteworthy effect is that as long as any idle watchers are |
1323 | active, the process will not block when waiting for new events. |
1413 | active, the process will not block when waiting for new events. |
1324 | |
1414 | |
1325 | Apart from keeping your process non-blocking (which is a useful |
1415 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1403 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1493 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1404 | macros, but using them is utterly, utterly and completely pointless. |
1494 | macros, but using them is utterly, utterly and completely pointless. |
1405 | |
1495 | |
1406 | =back |
1496 | =back |
1407 | |
1497 | |
1408 | Example: To include a library such as adns, you would add IO watchers |
1498 | There are a number of principal ways to embed other event loops or modules |
1409 | and a timeout watcher in a prepare handler, as required by libadns, and |
1499 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1500 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
|
|
1501 | use for an actually working example. Another Perl module named C<EV::Glib> |
|
|
1502 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
|
|
1503 | into the Glib event loop). |
|
|
1504 | |
|
|
1505 | Method 1: Add IO watchers and a timeout watcher in a prepare handler, |
1410 | in a check watcher, destroy them and call into libadns. What follows is |
1506 | and in a check watcher, destroy them and call into libadns. What follows |
1411 | pseudo-code only of course: |
1507 | is pseudo-code only of course. This requires you to either use a low |
|
|
1508 | priority for the check watcher or use C<ev_clear_pending> explicitly, as |
|
|
1509 | the callbacks for the IO/timeout watchers might not have been called yet. |
1412 | |
1510 | |
1413 | static ev_io iow [nfd]; |
1511 | static ev_io iow [nfd]; |
1414 | static ev_timer tw; |
1512 | static ev_timer tw; |
1415 | |
1513 | |
1416 | static void |
1514 | static void |
1417 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1515 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1418 | { |
1516 | { |
1419 | // set the relevant poll flags |
|
|
1420 | // could also call adns_processreadable etc. here |
|
|
1421 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1422 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1423 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1424 | } |
1517 | } |
1425 | |
1518 | |
1426 | // create io watchers for each fd and a timer before blocking |
1519 | // create io watchers for each fd and a timer before blocking |
1427 | static void |
1520 | static void |
1428 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1521 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1429 | { |
1522 | { |
1430 | int timeout = 3600000;truct pollfd fds [nfd]; |
1523 | int timeout = 3600000; |
|
|
1524 | struct pollfd fds [nfd]; |
1431 | // actual code will need to loop here and realloc etc. |
1525 | // actual code will need to loop here and realloc etc. |
1432 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1526 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1433 | |
1527 | |
1434 | /* the callback is illegal, but won't be called as we stop during check */ |
1528 | /* the callback is illegal, but won't be called as we stop during check */ |
1435 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1529 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1436 | ev_timer_start (loop, &tw); |
1530 | ev_timer_start (loop, &tw); |
1437 | |
1531 | |
1438 | // create on ev_io per pollfd |
1532 | // create one ev_io per pollfd |
1439 | for (int i = 0; i < nfd; ++i) |
1533 | for (int i = 0; i < nfd; ++i) |
1440 | { |
1534 | { |
1441 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1535 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1442 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1536 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1443 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1537 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1444 | |
1538 | |
1445 | fds [i].revents = 0; |
1539 | fds [i].revents = 0; |
1446 | iow [i].data = fds + i; |
|
|
1447 | ev_io_start (loop, iow + i); |
1540 | ev_io_start (loop, iow + i); |
1448 | } |
1541 | } |
1449 | } |
1542 | } |
1450 | |
1543 | |
1451 | // stop all watchers after blocking |
1544 | // stop all watchers after blocking |
… | |
… | |
1453 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1546 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1454 | { |
1547 | { |
1455 | ev_timer_stop (loop, &tw); |
1548 | ev_timer_stop (loop, &tw); |
1456 | |
1549 | |
1457 | for (int i = 0; i < nfd; ++i) |
1550 | for (int i = 0; i < nfd; ++i) |
|
|
1551 | { |
|
|
1552 | // set the relevant poll flags |
|
|
1553 | // could also call adns_processreadable etc. here |
|
|
1554 | struct pollfd *fd = fds + i; |
|
|
1555 | int revents = ev_clear_pending (iow + i); |
|
|
1556 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1557 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1558 | |
|
|
1559 | // now stop the watcher |
1458 | ev_io_stop (loop, iow + i); |
1560 | ev_io_stop (loop, iow + i); |
|
|
1561 | } |
1459 | |
1562 | |
1460 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1563 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1564 | } |
|
|
1565 | |
|
|
1566 | Method 2: This would be just like method 1, but you run C<adns_afterpoll> |
|
|
1567 | in the prepare watcher and would dispose of the check watcher. |
|
|
1568 | |
|
|
1569 | Method 3: If the module to be embedded supports explicit event |
|
|
1570 | notification (adns does), you can also make use of the actual watcher |
|
|
1571 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1572 | |
|
|
1573 | static void |
|
|
1574 | timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1575 | { |
|
|
1576 | adns_state ads = (adns_state)w->data; |
|
|
1577 | update_now (EV_A); |
|
|
1578 | |
|
|
1579 | adns_processtimeouts (ads, &tv_now); |
|
|
1580 | } |
|
|
1581 | |
|
|
1582 | static void |
|
|
1583 | io_cb (EV_P_ ev_io *w, int revents) |
|
|
1584 | { |
|
|
1585 | adns_state ads = (adns_state)w->data; |
|
|
1586 | update_now (EV_A); |
|
|
1587 | |
|
|
1588 | if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1589 | if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1590 | } |
|
|
1591 | |
|
|
1592 | // do not ever call adns_afterpoll |
|
|
1593 | |
|
|
1594 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1595 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1596 | their poll function. The drawback with this solution is that the main |
|
|
1597 | loop is now no longer controllable by EV. The C<Glib::EV> module does |
|
|
1598 | this. |
|
|
1599 | |
|
|
1600 | static gint |
|
|
1601 | event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1602 | { |
|
|
1603 | int got_events = 0; |
|
|
1604 | |
|
|
1605 | for (n = 0; n < nfds; ++n) |
|
|
1606 | // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1607 | |
|
|
1608 | if (timeout >= 0) |
|
|
1609 | // create/start timer |
|
|
1610 | |
|
|
1611 | // poll |
|
|
1612 | ev_loop (EV_A_ 0); |
|
|
1613 | |
|
|
1614 | // stop timer again |
|
|
1615 | if (timeout >= 0) |
|
|
1616 | ev_timer_stop (EV_A_ &to); |
|
|
1617 | |
|
|
1618 | // stop io watchers again - their callbacks should have set |
|
|
1619 | for (n = 0; n < nfds; ++n) |
|
|
1620 | ev_io_stop (EV_A_ iow [n]); |
|
|
1621 | |
|
|
1622 | return got_events; |
1461 | } |
1623 | } |
1462 | |
1624 | |
1463 | |
1625 | |
1464 | =head2 C<ev_embed> - when one backend isn't enough... |
1626 | =head2 C<ev_embed> - when one backend isn't enough... |
1465 | |
1627 | |
… | |
… | |
1669 | |
1831 | |
1670 | To use it, |
1832 | To use it, |
1671 | |
1833 | |
1672 | #include <ev++.h> |
1834 | #include <ev++.h> |
1673 | |
1835 | |
1674 | (it is not installed by default). This automatically includes F<ev.h> |
1836 | This automatically includes F<ev.h> and puts all of its definitions (many |
1675 | and puts all of its definitions (many of them macros) into the global |
1837 | of them macros) into the global namespace. All C++ specific things are |
1676 | namespace. All C++ specific things are put into the C<ev> namespace. |
1838 | put into the C<ev> namespace. It should support all the same embedding |
|
|
1839 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
1677 | |
1840 | |
1678 | It should support all the same embedding options as F<ev.h>, most notably |
1841 | Care has been taken to keep the overhead low. The only data member the C++ |
1679 | C<EV_MULTIPLICITY>. |
1842 | classes add (compared to plain C-style watchers) is the event loop pointer |
|
|
1843 | that the watcher is associated with (or no additional members at all if |
|
|
1844 | you disable C<EV_MULTIPLICITY> when embedding libev). |
|
|
1845 | |
|
|
1846 | Currently, functions, and static and non-static member functions can be |
|
|
1847 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1848 | need one additional pointer for context. If you need support for other |
|
|
1849 | types of functors please contact the author (preferably after implementing |
|
|
1850 | it). |
1680 | |
1851 | |
1681 | Here is a list of things available in the C<ev> namespace: |
1852 | Here is a list of things available in the C<ev> namespace: |
1682 | |
1853 | |
1683 | =over 4 |
1854 | =over 4 |
1684 | |
1855 | |
… | |
… | |
1700 | |
1871 | |
1701 | All of those classes have these methods: |
1872 | All of those classes have these methods: |
1702 | |
1873 | |
1703 | =over 4 |
1874 | =over 4 |
1704 | |
1875 | |
1705 | =item ev::TYPE::TYPE (object *, object::method *) |
1876 | =item ev::TYPE::TYPE () |
1706 | |
1877 | |
1707 | =item ev::TYPE::TYPE (object *, object::method *, struct ev_loop *) |
1878 | =item ev::TYPE::TYPE (struct ev_loop *) |
1708 | |
1879 | |
1709 | =item ev::TYPE::~TYPE |
1880 | =item ev::TYPE::~TYPE |
1710 | |
1881 | |
1711 | The constructor takes a pointer to an object and a method pointer to |
1882 | The constructor (optionally) takes an event loop to associate the watcher |
1712 | the event handler callback to call in this class. The constructor calls |
1883 | with. If it is omitted, it will use C<EV_DEFAULT>. |
1713 | C<ev_init> for you, which means you have to call the C<set> method |
1884 | |
1714 | before starting it. If you do not specify a loop then the constructor |
1885 | The constructor calls C<ev_init> for you, which means you have to call the |
1715 | automatically associates the default loop with this watcher. |
1886 | C<set> method before starting it. |
|
|
1887 | |
|
|
1888 | It will not set a callback, however: You have to call the templated C<set> |
|
|
1889 | method to set a callback before you can start the watcher. |
|
|
1890 | |
|
|
1891 | (The reason why you have to use a method is a limitation in C++ which does |
|
|
1892 | not allow explicit template arguments for constructors). |
1716 | |
1893 | |
1717 | The destructor automatically stops the watcher if it is active. |
1894 | The destructor automatically stops the watcher if it is active. |
|
|
1895 | |
|
|
1896 | =item w->set<class, &class::method> (object *) |
|
|
1897 | |
|
|
1898 | This method sets the callback method to call. The method has to have a |
|
|
1899 | signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as |
|
|
1900 | first argument and the C<revents> as second. The object must be given as |
|
|
1901 | parameter and is stored in the C<data> member of the watcher. |
|
|
1902 | |
|
|
1903 | This method synthesizes efficient thunking code to call your method from |
|
|
1904 | the C callback that libev requires. If your compiler can inline your |
|
|
1905 | callback (i.e. it is visible to it at the place of the C<set> call and |
|
|
1906 | your compiler is good :), then the method will be fully inlined into the |
|
|
1907 | thunking function, making it as fast as a direct C callback. |
|
|
1908 | |
|
|
1909 | Example: simple class declaration and watcher initialisation |
|
|
1910 | |
|
|
1911 | struct myclass |
|
|
1912 | { |
|
|
1913 | void io_cb (ev::io &w, int revents) { } |
|
|
1914 | } |
|
|
1915 | |
|
|
1916 | myclass obj; |
|
|
1917 | ev::io iow; |
|
|
1918 | iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1919 | |
|
|
1920 | =item w->set<function> (void *data = 0) |
|
|
1921 | |
|
|
1922 | Also sets a callback, but uses a static method or plain function as |
|
|
1923 | callback. The optional C<data> argument will be stored in the watcher's |
|
|
1924 | C<data> member and is free for you to use. |
|
|
1925 | |
|
|
1926 | The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>. |
|
|
1927 | |
|
|
1928 | See the method-C<set> above for more details. |
|
|
1929 | |
|
|
1930 | Example: |
|
|
1931 | |
|
|
1932 | static void io_cb (ev::io &w, int revents) { } |
|
|
1933 | iow.set <io_cb> (); |
1718 | |
1934 | |
1719 | =item w->set (struct ev_loop *) |
1935 | =item w->set (struct ev_loop *) |
1720 | |
1936 | |
1721 | Associates a different C<struct ev_loop> with this watcher. You can only |
1937 | Associates a different C<struct ev_loop> with this watcher. You can only |
1722 | do this when the watcher is inactive (and not pending either). |
1938 | do this when the watcher is inactive (and not pending either). |
1723 | |
1939 | |
1724 | =item w->set ([args]) |
1940 | =item w->set ([args]) |
1725 | |
1941 | |
1726 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
1942 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
1727 | called at least once. Unlike the C counterpart, an active watcher gets |
1943 | called at least once. Unlike the C counterpart, an active watcher gets |
1728 | automatically stopped and restarted. |
1944 | automatically stopped and restarted when reconfiguring it with this |
|
|
1945 | method. |
1729 | |
1946 | |
1730 | =item w->start () |
1947 | =item w->start () |
1731 | |
1948 | |
1732 | Starts the watcher. Note that there is no C<loop> argument as the |
1949 | Starts the watcher. Note that there is no C<loop> argument, as the |
1733 | constructor already takes the loop. |
1950 | constructor already stores the event loop. |
1734 | |
1951 | |
1735 | =item w->stop () |
1952 | =item w->stop () |
1736 | |
1953 | |
1737 | Stops the watcher if it is active. Again, no C<loop> argument. |
1954 | Stops the watcher if it is active. Again, no C<loop> argument. |
1738 | |
1955 | |
… | |
… | |
1763 | |
1980 | |
1764 | myclass (); |
1981 | myclass (); |
1765 | } |
1982 | } |
1766 | |
1983 | |
1767 | myclass::myclass (int fd) |
1984 | myclass::myclass (int fd) |
1768 | : io (this, &myclass::io_cb), |
|
|
1769 | idle (this, &myclass::idle_cb) |
|
|
1770 | { |
1985 | { |
|
|
1986 | io .set <myclass, &myclass::io_cb > (this); |
|
|
1987 | idle.set <myclass, &myclass::idle_cb> (this); |
|
|
1988 | |
1771 | io.start (fd, ev::READ); |
1989 | io.start (fd, ev::READ); |
1772 | } |
1990 | } |
1773 | |
1991 | |
1774 | |
1992 | |
1775 | =head1 MACRO MAGIC |
1993 | =head1 MACRO MAGIC |
1776 | |
1994 | |
1777 | Libev can be compiled with a variety of options, the most fundemantal is |
1995 | Libev can be compiled with a variety of options, the most fundemantal is |
1778 | C<EV_MULTIPLICITY>. This option determines wether (most) functions and |
1996 | C<EV_MULTIPLICITY>. This option determines whether (most) functions and |
1779 | callbacks have an initial C<struct ev_loop *> argument. |
1997 | callbacks have an initial C<struct ev_loop *> argument. |
1780 | |
1998 | |
1781 | To make it easier to write programs that cope with either variant, the |
1999 | To make it easier to write programs that cope with either variant, the |
1782 | following macros are defined: |
2000 | following macros are defined: |
1783 | |
2001 | |
… | |
… | |
1816 | Similar to the other two macros, this gives you the value of the default |
2034 | Similar to the other two macros, this gives you the value of the default |
1817 | loop, if multiple loops are supported ("ev loop default"). |
2035 | loop, if multiple loops are supported ("ev loop default"). |
1818 | |
2036 | |
1819 | =back |
2037 | =back |
1820 | |
2038 | |
1821 | Example: Declare and initialise a check watcher, working regardless of |
2039 | Example: Declare and initialise a check watcher, utilising the above |
1822 | wether multiple loops are supported or not. |
2040 | macros so it will work regardless of whether multiple loops are supported |
|
|
2041 | or not. |
1823 | |
2042 | |
1824 | static void |
2043 | static void |
1825 | check_cb (EV_P_ ev_timer *w, int revents) |
2044 | check_cb (EV_P_ ev_timer *w, int revents) |
1826 | { |
2045 | { |
1827 | ev_check_stop (EV_A_ w); |
2046 | ev_check_stop (EV_A_ w); |
… | |
… | |
1829 | |
2048 | |
1830 | ev_check check; |
2049 | ev_check check; |
1831 | ev_check_init (&check, check_cb); |
2050 | ev_check_init (&check, check_cb); |
1832 | ev_check_start (EV_DEFAULT_ &check); |
2051 | ev_check_start (EV_DEFAULT_ &check); |
1833 | ev_loop (EV_DEFAULT_ 0); |
2052 | ev_loop (EV_DEFAULT_ 0); |
1834 | |
|
|
1835 | |
2053 | |
1836 | =head1 EMBEDDING |
2054 | =head1 EMBEDDING |
1837 | |
2055 | |
1838 | Libev can (and often is) directly embedded into host |
2056 | Libev can (and often is) directly embedded into host |
1839 | applications. Examples of applications that embed it include the Deliantra |
2057 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1879 | ev_vars.h |
2097 | ev_vars.h |
1880 | ev_wrap.h |
2098 | ev_wrap.h |
1881 | |
2099 | |
1882 | ev_win32.c required on win32 platforms only |
2100 | ev_win32.c required on win32 platforms only |
1883 | |
2101 | |
1884 | ev_select.c only when select backend is enabled (which is by default) |
2102 | ev_select.c only when select backend is enabled (which is enabled by default) |
1885 | ev_poll.c only when poll backend is enabled (disabled by default) |
2103 | ev_poll.c only when poll backend is enabled (disabled by default) |
1886 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2104 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1887 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2105 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1888 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
2106 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1889 | |
2107 | |
… | |
… | |
2052 | will have the C<struct ev_loop *> as first argument, and you can create |
2270 | will have the C<struct ev_loop *> as first argument, and you can create |
2053 | additional independent event loops. Otherwise there will be no support |
2271 | additional independent event loops. Otherwise there will be no support |
2054 | for multiple event loops and there is no first event loop pointer |
2272 | for multiple event loops and there is no first event loop pointer |
2055 | argument. Instead, all functions act on the single default loop. |
2273 | argument. Instead, all functions act on the single default loop. |
2056 | |
2274 | |
|
|
2275 | =item EV_MINPRI |
|
|
2276 | |
|
|
2277 | =item EV_MAXPRI |
|
|
2278 | |
|
|
2279 | The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to |
|
|
2280 | C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can |
|
|
2281 | provide for more priorities by overriding those symbols (usually defined |
|
|
2282 | to be C<-2> and C<2>, respectively). |
|
|
2283 | |
|
|
2284 | When doing priority-based operations, libev usually has to linearly search |
|
|
2285 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2286 | and time, so using the defaults of five priorities (-2 .. +2) is usually |
|
|
2287 | fine. |
|
|
2288 | |
|
|
2289 | If your embedding app does not need any priorities, defining these both to |
|
|
2290 | C<0> will save some memory and cpu. |
|
|
2291 | |
2057 | =item EV_PERIODIC_ENABLE |
2292 | =item EV_PERIODIC_ENABLE |
2058 | |
2293 | |
2059 | If undefined or defined to be C<1>, then periodic timers are supported. If |
2294 | If undefined or defined to be C<1>, then periodic timers are supported. If |
|
|
2295 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2296 | code. |
|
|
2297 | |
|
|
2298 | =item EV_IDLE_ENABLE |
|
|
2299 | |
|
|
2300 | If undefined or defined to be C<1>, then idle watchers are supported. If |
2060 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2301 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2061 | code. |
2302 | code. |
2062 | |
2303 | |
2063 | =item EV_EMBED_ENABLE |
2304 | =item EV_EMBED_ENABLE |
2064 | |
2305 | |
… | |
… | |
2131 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2372 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2132 | will be compiled. It is pretty complex because it provides its own header |
2373 | will be compiled. It is pretty complex because it provides its own header |
2133 | file. |
2374 | file. |
2134 | |
2375 | |
2135 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2376 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2136 | that everybody includes and which overrides some autoconf choices: |
2377 | that everybody includes and which overrides some configure choices: |
2137 | |
2378 | |
|
|
2379 | #define EV_MINIMAL 1 |
2138 | #define EV_USE_POLL 0 |
2380 | #define EV_USE_POLL 0 |
2139 | #define EV_MULTIPLICITY 0 |
2381 | #define EV_MULTIPLICITY 0 |
2140 | #define EV_PERIODICS 0 |
2382 | #define EV_PERIODIC_ENABLE 0 |
|
|
2383 | #define EV_STAT_ENABLE 0 |
|
|
2384 | #define EV_FORK_ENABLE 0 |
2141 | #define EV_CONFIG_H <config.h> |
2385 | #define EV_CONFIG_H <config.h> |
|
|
2386 | #define EV_MINPRI 0 |
|
|
2387 | #define EV_MAXPRI 0 |
2142 | |
2388 | |
2143 | #include "ev++.h" |
2389 | #include "ev++.h" |
2144 | |
2390 | |
2145 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2391 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2146 | |
2392 | |
… | |
… | |
2152 | |
2398 | |
2153 | In this section the complexities of (many of) the algorithms used inside |
2399 | In this section the complexities of (many of) the algorithms used inside |
2154 | libev will be explained. For complexity discussions about backends see the |
2400 | libev will be explained. For complexity discussions about backends see the |
2155 | documentation for C<ev_default_init>. |
2401 | documentation for C<ev_default_init>. |
2156 | |
2402 | |
|
|
2403 | All of the following are about amortised time: If an array needs to be |
|
|
2404 | extended, libev needs to realloc and move the whole array, but this |
|
|
2405 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2406 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2407 | it is much faster and asymptotically approaches constant time. |
|
|
2408 | |
2157 | =over 4 |
2409 | =over 4 |
2158 | |
2410 | |
2159 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2411 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2160 | |
2412 | |
|
|
2413 | This means that, when you have a watcher that triggers in one hour and |
|
|
2414 | there are 100 watchers that would trigger before that then inserting will |
|
|
2415 | have to skip those 100 watchers. |
|
|
2416 | |
2161 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2417 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2162 | |
2418 | |
|
|
2419 | That means that for changing a timer costs less than removing/adding them |
|
|
2420 | as only the relative motion in the event queue has to be paid for. |
|
|
2421 | |
2163 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2422 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2164 | |
2423 | |
|
|
2424 | These just add the watcher into an array or at the head of a list. |
2165 | =item Stopping check/prepare/idle watchers: O(1) |
2425 | =item Stopping check/prepare/idle watchers: O(1) |
2166 | |
2426 | |
2167 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2427 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2168 | |
2428 | |
|
|
2429 | These watchers are stored in lists then need to be walked to find the |
|
|
2430 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2431 | have many watchers waiting for the same fd or signal). |
|
|
2432 | |
2169 | =item Finding the next timer per loop iteration: O(1) |
2433 | =item Finding the next timer per loop iteration: O(1) |
2170 | |
2434 | |
2171 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2435 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2172 | |
2436 | |
|
|
2437 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2438 | libev to recalculate its status (and possibly tell the kernel). |
|
|
2439 | |
2173 | =item Activating one watcher: O(1) |
2440 | =item Activating one watcher: O(1) |
2174 | |
2441 | |
|
|
2442 | =item Priority handling: O(number_of_priorities) |
|
|
2443 | |
|
|
2444 | Priorities are implemented by allocating some space for each |
|
|
2445 | priority. When doing priority-based operations, libev usually has to |
|
|
2446 | linearly search all the priorities. |
|
|
2447 | |
2175 | =back |
2448 | =back |
2176 | |
2449 | |
2177 | |
2450 | |
2178 | =head1 AUTHOR |
2451 | =head1 AUTHOR |
2179 | |
2452 | |