… | |
… | |
266 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
266 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
267 | override the flags completely if it is found in the environment. This is |
267 | override the flags completely if it is found in the environment. This is |
268 | useful to try out specific backends to test their performance, or to work |
268 | useful to try out specific backends to test their performance, or to work |
269 | around bugs. |
269 | around bugs. |
270 | |
270 | |
|
|
271 | =item C<EVFLAG_FORKCHECK> |
|
|
272 | |
|
|
273 | Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after |
|
|
274 | a fork, you can also make libev check for a fork in each iteration by |
|
|
275 | enabling this flag. |
|
|
276 | |
|
|
277 | This works by calling C<getpid ()> on every iteration of the loop, |
|
|
278 | and thus this might slow down your event loop if you do a lot of loop |
|
|
279 | iterations and little real work, but is usually not noticeable (on my |
|
|
280 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
|
|
281 | without a syscall and thus I<very> fast, but my Linux system also has |
|
|
282 | C<pthread_atfork> which is even faster). |
|
|
283 | |
|
|
284 | The big advantage of this flag is that you can forget about fork (and |
|
|
285 | forget about forgetting to tell libev about forking) when you use this |
|
|
286 | flag. |
|
|
287 | |
|
|
288 | This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS> |
|
|
289 | environment variable. |
|
|
290 | |
271 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
291 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
272 | |
292 | |
273 | This is your standard select(2) backend. Not I<completely> standard, as |
293 | This is your standard select(2) backend. Not I<completely> standard, as |
274 | libev tries to roll its own fd_set with no limits on the number of fds, |
294 | libev tries to roll its own fd_set with no limits on the number of fds, |
275 | but if that fails, expect a fairly low limit on the number of fds when |
295 | but if that fails, expect a fairly low limit on the number of fds when |
… | |
… | |
409 | =item ev_loop_fork (loop) |
429 | =item ev_loop_fork (loop) |
410 | |
430 | |
411 | Like C<ev_default_fork>, but acts on an event loop created by |
431 | Like C<ev_default_fork>, but acts on an event loop created by |
412 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
432 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
413 | after fork, and how you do this is entirely your own problem. |
433 | after fork, and how you do this is entirely your own problem. |
|
|
434 | |
|
|
435 | =item unsigned int ev_loop_count (loop) |
|
|
436 | |
|
|
437 | Returns the count of loop iterations for the loop, which is identical to |
|
|
438 | the number of times libev did poll for new events. It starts at C<0> and |
|
|
439 | happily wraps around with enough iterations. |
|
|
440 | |
|
|
441 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
442 | "ticks" the number of loop iterations), as it roughly corresponds with |
|
|
443 | C<ev_prepare> and C<ev_check> calls. |
414 | |
444 | |
415 | =item unsigned int ev_backend (loop) |
445 | =item unsigned int ev_backend (loop) |
416 | |
446 | |
417 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
447 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
418 | use. |
448 | use. |
… | |
… | |
714 | =item ev_cb_set (ev_TYPE *watcher, callback) |
744 | =item ev_cb_set (ev_TYPE *watcher, callback) |
715 | |
745 | |
716 | Change the callback. You can change the callback at virtually any time |
746 | Change the callback. You can change the callback at virtually any time |
717 | (modulo threads). |
747 | (modulo threads). |
718 | |
748 | |
|
|
749 | =item ev_set_priority (ev_TYPE *watcher, priority) |
|
|
750 | |
|
|
751 | =item int ev_priority (ev_TYPE *watcher) |
|
|
752 | |
|
|
753 | Set and query the priority of the watcher. The priority is a small |
|
|
754 | integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> |
|
|
755 | (default: C<-2>). Pending watchers with higher priority will be invoked |
|
|
756 | before watchers with lower priority, but priority will not keep watchers |
|
|
757 | from being executed (except for C<ev_idle> watchers). |
|
|
758 | |
|
|
759 | This means that priorities are I<only> used for ordering callback |
|
|
760 | invocation after new events have been received. This is useful, for |
|
|
761 | example, to reduce latency after idling, or more often, to bind two |
|
|
762 | watchers on the same event and make sure one is called first. |
|
|
763 | |
|
|
764 | If you need to suppress invocation when higher priority events are pending |
|
|
765 | you need to look at C<ev_idle> watchers, which provide this functionality. |
|
|
766 | |
|
|
767 | The default priority used by watchers when no priority has been set is |
|
|
768 | always C<0>, which is supposed to not be too high and not be too low :). |
|
|
769 | |
|
|
770 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
|
|
771 | fine, as long as you do not mind that the priority value you query might |
|
|
772 | or might not have been adjusted to be within valid range. |
|
|
773 | |
719 | =back |
774 | =back |
720 | |
775 | |
721 | |
776 | |
722 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
777 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
723 | |
778 | |
… | |
… | |
828 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
883 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
829 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
884 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
830 | |
885 | |
831 | If you cannot run the fd in non-blocking mode (for example you should not |
886 | If you cannot run the fd in non-blocking mode (for example you should not |
832 | play around with an Xlib connection), then you have to seperately re-test |
887 | play around with an Xlib connection), then you have to seperately re-test |
833 | wether a file descriptor is really ready with a known-to-be good interface |
888 | whether a file descriptor is really ready with a known-to-be good interface |
834 | such as poll (fortunately in our Xlib example, Xlib already does this on |
889 | such as poll (fortunately in our Xlib example, Xlib already does this on |
835 | its own, so its quite safe to use). |
890 | its own, so its quite safe to use). |
836 | |
891 | |
837 | =over 4 |
892 | =over 4 |
838 | |
893 | |
… | |
… | |
916 | =item ev_timer_again (loop) |
971 | =item ev_timer_again (loop) |
917 | |
972 | |
918 | This will act as if the timer timed out and restart it again if it is |
973 | This will act as if the timer timed out and restart it again if it is |
919 | repeating. The exact semantics are: |
974 | repeating. The exact semantics are: |
920 | |
975 | |
|
|
976 | If the timer is pending, its pending status is cleared. |
|
|
977 | |
921 | If the timer is started but nonrepeating, stop it. |
978 | If the timer is started but nonrepeating, stop it (as if it timed out). |
922 | |
979 | |
923 | If the timer is repeating, either start it if necessary (with the repeat |
980 | If the timer is repeating, either start it if necessary (with the |
924 | value), or reset the running timer to the repeat value. |
981 | C<repeat> value), or reset the running timer to the C<repeat> value. |
925 | |
982 | |
926 | This sounds a bit complicated, but here is a useful and typical |
983 | This sounds a bit complicated, but here is a useful and typical |
927 | example: Imagine you have a tcp connection and you want a so-called |
984 | example: Imagine you have a tcp connection and you want a so-called idle |
928 | idle timeout, that is, you want to be called when there have been, |
985 | timeout, that is, you want to be called when there have been, say, 60 |
929 | say, 60 seconds of inactivity on the socket. The easiest way to do |
986 | seconds of inactivity on the socket. The easiest way to do this is to |
930 | this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling |
987 | configure an C<ev_timer> with a C<repeat> value of C<60> and then call |
931 | C<ev_timer_again> each time you successfully read or write some data. If |
988 | C<ev_timer_again> each time you successfully read or write some data. If |
932 | you go into an idle state where you do not expect data to travel on the |
989 | you go into an idle state where you do not expect data to travel on the |
933 | socket, you can stop the timer, and again will automatically restart it if |
990 | socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will |
934 | need be. |
991 | automatically restart it if need be. |
935 | |
992 | |
936 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
993 | That means you can ignore the C<after> value and C<ev_timer_start> |
937 | and only ever use the C<repeat> value: |
994 | altogether and only ever use the C<repeat> value and C<ev_timer_again>: |
938 | |
995 | |
939 | ev_timer_init (timer, callback, 0., 5.); |
996 | ev_timer_init (timer, callback, 0., 5.); |
940 | ev_timer_again (loop, timer); |
997 | ev_timer_again (loop, timer); |
941 | ... |
998 | ... |
942 | timer->again = 17.; |
999 | timer->again = 17.; |
943 | ev_timer_again (loop, timer); |
1000 | ev_timer_again (loop, timer); |
944 | ... |
1001 | ... |
945 | timer->again = 10.; |
1002 | timer->again = 10.; |
946 | ev_timer_again (loop, timer); |
1003 | ev_timer_again (loop, timer); |
947 | |
1004 | |
948 | This is more efficient then stopping/starting the timer eahc time you want |
1005 | This is more slightly efficient then stopping/starting the timer each time |
949 | to modify its timeout value. |
1006 | you want to modify its timeout value. |
950 | |
1007 | |
951 | =item ev_tstamp repeat [read-write] |
1008 | =item ev_tstamp repeat [read-write] |
952 | |
1009 | |
953 | The current C<repeat> value. Will be used each time the watcher times out |
1010 | The current C<repeat> value. Will be used each time the watcher times out |
954 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1011 | or C<ev_timer_again> is called and determines the next timeout (if any), |
… | |
… | |
1319 | ev_stat_start (loop, &passwd); |
1376 | ev_stat_start (loop, &passwd); |
1320 | |
1377 | |
1321 | |
1378 | |
1322 | =head2 C<ev_idle> - when you've got nothing better to do... |
1379 | =head2 C<ev_idle> - when you've got nothing better to do... |
1323 | |
1380 | |
1324 | Idle watchers trigger events when there are no other events are pending |
1381 | Idle watchers trigger events when no other events of the same or higher |
1325 | (prepare, check and other idle watchers do not count). That is, as long |
1382 | priority are pending (prepare, check and other idle watchers do not |
1326 | as your process is busy handling sockets or timeouts (or even signals, |
1383 | count). |
1327 | imagine) it will not be triggered. But when your process is idle all idle |
1384 | |
1328 | watchers are being called again and again, once per event loop iteration - |
1385 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1386 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1387 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1388 | are pending), the idle watchers are being called once per event loop |
1329 | until stopped, that is, or your process receives more events and becomes |
1389 | iteration - until stopped, that is, or your process receives more events |
1330 | busy. |
1390 | and becomes busy again with higher priority stuff. |
1331 | |
1391 | |
1332 | The most noteworthy effect is that as long as any idle watchers are |
1392 | The most noteworthy effect is that as long as any idle watchers are |
1333 | active, the process will not block when waiting for new events. |
1393 | active, the process will not block when waiting for new events. |
1334 | |
1394 | |
1335 | Apart from keeping your process non-blocking (which is a useful |
1395 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1435 | |
1495 | |
1436 | // create io watchers for each fd and a timer before blocking |
1496 | // create io watchers for each fd and a timer before blocking |
1437 | static void |
1497 | static void |
1438 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1498 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1439 | { |
1499 | { |
1440 | int timeout = 3600000;truct pollfd fds [nfd]; |
1500 | int timeout = 3600000; |
|
|
1501 | struct pollfd fds [nfd]; |
1441 | // actual code will need to loop here and realloc etc. |
1502 | // actual code will need to loop here and realloc etc. |
1442 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1503 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1443 | |
1504 | |
1444 | /* the callback is illegal, but won't be called as we stop during check */ |
1505 | /* the callback is illegal, but won't be called as we stop during check */ |
1445 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1506 | ev_timer_init (&tw, 0, timeout * 1e-3); |
… | |
… | |
1783 | |
1844 | |
1784 | |
1845 | |
1785 | =head1 MACRO MAGIC |
1846 | =head1 MACRO MAGIC |
1786 | |
1847 | |
1787 | Libev can be compiled with a variety of options, the most fundemantal is |
1848 | Libev can be compiled with a variety of options, the most fundemantal is |
1788 | C<EV_MULTIPLICITY>. This option determines wether (most) functions and |
1849 | C<EV_MULTIPLICITY>. This option determines whether (most) functions and |
1789 | callbacks have an initial C<struct ev_loop *> argument. |
1850 | callbacks have an initial C<struct ev_loop *> argument. |
1790 | |
1851 | |
1791 | To make it easier to write programs that cope with either variant, the |
1852 | To make it easier to write programs that cope with either variant, the |
1792 | following macros are defined: |
1853 | following macros are defined: |
1793 | |
1854 | |
… | |
… | |
1826 | Similar to the other two macros, this gives you the value of the default |
1887 | Similar to the other two macros, this gives you the value of the default |
1827 | loop, if multiple loops are supported ("ev loop default"). |
1888 | loop, if multiple loops are supported ("ev loop default"). |
1828 | |
1889 | |
1829 | =back |
1890 | =back |
1830 | |
1891 | |
1831 | Example: Declare and initialise a check watcher, working regardless of |
1892 | Example: Declare and initialise a check watcher, utilising the above |
1832 | wether multiple loops are supported or not. |
1893 | macros so it will work regardless of whether multiple loops are supported |
|
|
1894 | or not. |
1833 | |
1895 | |
1834 | static void |
1896 | static void |
1835 | check_cb (EV_P_ ev_timer *w, int revents) |
1897 | check_cb (EV_P_ ev_timer *w, int revents) |
1836 | { |
1898 | { |
1837 | ev_check_stop (EV_A_ w); |
1899 | ev_check_stop (EV_A_ w); |
… | |
… | |
1839 | |
1901 | |
1840 | ev_check check; |
1902 | ev_check check; |
1841 | ev_check_init (&check, check_cb); |
1903 | ev_check_init (&check, check_cb); |
1842 | ev_check_start (EV_DEFAULT_ &check); |
1904 | ev_check_start (EV_DEFAULT_ &check); |
1843 | ev_loop (EV_DEFAULT_ 0); |
1905 | ev_loop (EV_DEFAULT_ 0); |
1844 | |
|
|
1845 | |
1906 | |
1846 | =head1 EMBEDDING |
1907 | =head1 EMBEDDING |
1847 | |
1908 | |
1848 | Libev can (and often is) directly embedded into host |
1909 | Libev can (and often is) directly embedded into host |
1849 | applications. Examples of applications that embed it include the Deliantra |
1910 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1889 | ev_vars.h |
1950 | ev_vars.h |
1890 | ev_wrap.h |
1951 | ev_wrap.h |
1891 | |
1952 | |
1892 | ev_win32.c required on win32 platforms only |
1953 | ev_win32.c required on win32 platforms only |
1893 | |
1954 | |
1894 | ev_select.c only when select backend is enabled (which is by default) |
1955 | ev_select.c only when select backend is enabled (which is enabled by default) |
1895 | ev_poll.c only when poll backend is enabled (disabled by default) |
1956 | ev_poll.c only when poll backend is enabled (disabled by default) |
1896 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1957 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1897 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1958 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1898 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1959 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1899 | |
1960 | |
… | |
… | |
2068 | |
2129 | |
2069 | If undefined or defined to be C<1>, then periodic timers are supported. If |
2130 | If undefined or defined to be C<1>, then periodic timers are supported. If |
2070 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2131 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2071 | code. |
2132 | code. |
2072 | |
2133 | |
|
|
2134 | =item EV_IDLE_ENABLE |
|
|
2135 | |
|
|
2136 | If undefined or defined to be C<1>, then idle watchers are supported. If |
|
|
2137 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2138 | code. |
|
|
2139 | |
2073 | =item EV_EMBED_ENABLE |
2140 | =item EV_EMBED_ENABLE |
2074 | |
2141 | |
2075 | If undefined or defined to be C<1>, then embed watchers are supported. If |
2142 | If undefined or defined to be C<1>, then embed watchers are supported. If |
2076 | defined to be C<0>, then they are not. |
2143 | defined to be C<0>, then they are not. |
2077 | |
2144 | |
… | |
… | |
2141 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2208 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2142 | will be compiled. It is pretty complex because it provides its own header |
2209 | will be compiled. It is pretty complex because it provides its own header |
2143 | file. |
2210 | file. |
2144 | |
2211 | |
2145 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2212 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2146 | that everybody includes and which overrides some autoconf choices: |
2213 | that everybody includes and which overrides some configure choices: |
2147 | |
2214 | |
|
|
2215 | #define EV_MINIMAL 1 |
2148 | #define EV_USE_POLL 0 |
2216 | #define EV_USE_POLL 0 |
2149 | #define EV_MULTIPLICITY 0 |
2217 | #define EV_MULTIPLICITY 0 |
2150 | #define EV_PERIODICS 0 |
2218 | #define EV_PERIODIC_ENABLE 0 |
|
|
2219 | #define EV_STAT_ENABLE 0 |
|
|
2220 | #define EV_FORK_ENABLE 0 |
2151 | #define EV_CONFIG_H <config.h> |
2221 | #define EV_CONFIG_H <config.h> |
|
|
2222 | #define EV_MINPRI 0 |
|
|
2223 | #define EV_MAXPRI 0 |
2152 | |
2224 | |
2153 | #include "ev++.h" |
2225 | #include "ev++.h" |
2154 | |
2226 | |
2155 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2227 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2156 | |
2228 | |