… | |
… | |
82 | |
82 | |
83 | =head1 WHAT TO READ WHEN IN A HURRY |
83 | =head1 WHAT TO READ WHEN IN A HURRY |
84 | |
84 | |
85 | This manual tries to be very detailed, but unfortunately, this also makes |
85 | This manual tries to be very detailed, but unfortunately, this also makes |
86 | it very long. If you just want to know the basics of libev, I suggest |
86 | it very long. If you just want to know the basics of libev, I suggest |
87 | reading L<ANATOMY OF A WATCHER>, then the L<EXAMPLE PROGRAM> above and |
87 | reading L</ANATOMY OF A WATCHER>, then the L</EXAMPLE PROGRAM> above and |
88 | look up the missing functions in L<GLOBAL FUNCTIONS> and the C<ev_io> and |
88 | look up the missing functions in L</GLOBAL FUNCTIONS> and the C<ev_io> and |
89 | C<ev_timer> sections in L<WATCHER TYPES>. |
89 | C<ev_timer> sections in L</WATCHER TYPES>. |
90 | |
90 | |
91 | =head1 ABOUT LIBEV |
91 | =head1 ABOUT LIBEV |
92 | |
92 | |
93 | Libev is an event loop: you register interest in certain events (such as a |
93 | Libev is an event loop: you register interest in certain events (such as a |
94 | file descriptor being readable or a timeout occurring), and it will manage |
94 | file descriptor being readable or a timeout occurring), and it will manage |
… | |
… | |
247 | the current system, you would need to look at C<ev_embeddable_backends () |
247 | the current system, you would need to look at C<ev_embeddable_backends () |
248 | & ev_supported_backends ()>, likewise for recommended ones. |
248 | & ev_supported_backends ()>, likewise for recommended ones. |
249 | |
249 | |
250 | See the description of C<ev_embed> watchers for more info. |
250 | See the description of C<ev_embed> watchers for more info. |
251 | |
251 | |
252 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
252 | =item ev_set_allocator (void *(*cb)(void *ptr, long size) throw ()) |
253 | |
253 | |
254 | Sets the allocation function to use (the prototype is similar - the |
254 | Sets the allocation function to use (the prototype is similar - the |
255 | semantics are identical to the C<realloc> C89/SuS/POSIX function). It is |
255 | semantics are identical to the C<realloc> C89/SuS/POSIX function). It is |
256 | used to allocate and free memory (no surprises here). If it returns zero |
256 | used to allocate and free memory (no surprises here). If it returns zero |
257 | when memory needs to be allocated (C<size != 0>), the library might abort |
257 | when memory needs to be allocated (C<size != 0>), the library might abort |
… | |
… | |
283 | } |
283 | } |
284 | |
284 | |
285 | ... |
285 | ... |
286 | ev_set_allocator (persistent_realloc); |
286 | ev_set_allocator (persistent_realloc); |
287 | |
287 | |
288 | =item ev_set_syserr_cb (void (*cb)(const char *msg)) |
288 | =item ev_set_syserr_cb (void (*cb)(const char *msg) throw ()) |
289 | |
289 | |
290 | Set the callback function to call on a retryable system call error (such |
290 | Set the callback function to call on a retryable system call error (such |
291 | as failed select, poll, epoll_wait). The message is a printable string |
291 | as failed select, poll, epoll_wait). The message is a printable string |
292 | indicating the system call or subsystem causing the problem. If this |
292 | indicating the system call or subsystem causing the problem. If this |
293 | callback is set, then libev will expect it to remedy the situation, no |
293 | callback is set, then libev will expect it to remedy the situation, no |
… | |
… | |
567 | |
567 | |
568 | It scales in the same way as the epoll backend, but the interface to the |
568 | It scales in the same way as the epoll backend, but the interface to the |
569 | kernel is more efficient (which says nothing about its actual speed, of |
569 | kernel is more efficient (which says nothing about its actual speed, of |
570 | course). While stopping, setting and starting an I/O watcher does never |
570 | course). While stopping, setting and starting an I/O watcher does never |
571 | cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to |
571 | cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to |
572 | two event changes per incident. Support for C<fork ()> is very bad (but |
572 | two event changes per incident. Support for C<fork ()> is very bad (you |
573 | sane, unlike epoll) and it drops fds silently in similarly hard-to-detect |
573 | might have to leak fd's on fork, but it's more sane than epoll) and it |
574 | cases |
574 | drops fds silently in similarly hard-to-detect cases |
575 | |
575 | |
576 | This backend usually performs well under most conditions. |
576 | This backend usually performs well under most conditions. |
577 | |
577 | |
578 | While nominally embeddable in other event loops, this doesn't work |
578 | While nominally embeddable in other event loops, this doesn't work |
579 | everywhere, so you might need to test for this. And since it is broken |
579 | everywhere, so you might need to test for this. And since it is broken |
… | |
… | |
764 | |
764 | |
765 | This function is rarely useful, but when some event callback runs for a |
765 | This function is rarely useful, but when some event callback runs for a |
766 | very long time without entering the event loop, updating libev's idea of |
766 | very long time without entering the event loop, updating libev's idea of |
767 | the current time is a good idea. |
767 | the current time is a good idea. |
768 | |
768 | |
769 | See also L<The special problem of time updates> in the C<ev_timer> section. |
769 | See also L</The special problem of time updates> in the C<ev_timer> section. |
770 | |
770 | |
771 | =item ev_suspend (loop) |
771 | =item ev_suspend (loop) |
772 | |
772 | |
773 | =item ev_resume (loop) |
773 | =item ev_resume (loop) |
774 | |
774 | |
… | |
… | |
792 | without a previous call to C<ev_suspend>. |
792 | without a previous call to C<ev_suspend>. |
793 | |
793 | |
794 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
794 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
795 | event loop time (see C<ev_now_update>). |
795 | event loop time (see C<ev_now_update>). |
796 | |
796 | |
797 | =item ev_run (loop, int flags) |
797 | =item bool ev_run (loop, int flags) |
798 | |
798 | |
799 | Finally, this is it, the event handler. This function usually is called |
799 | Finally, this is it, the event handler. This function usually is called |
800 | after you have initialised all your watchers and you want to start |
800 | after you have initialised all your watchers and you want to start |
801 | handling events. It will ask the operating system for any new events, call |
801 | handling events. It will ask the operating system for any new events, call |
802 | the watcher callbacks, an then repeat the whole process indefinitely: This |
802 | the watcher callbacks, and then repeat the whole process indefinitely: This |
803 | is why event loops are called I<loops>. |
803 | is why event loops are called I<loops>. |
804 | |
804 | |
805 | If the flags argument is specified as C<0>, it will keep handling events |
805 | If the flags argument is specified as C<0>, it will keep handling events |
806 | until either no event watchers are active anymore or C<ev_break> was |
806 | until either no event watchers are active anymore or C<ev_break> was |
807 | called. |
807 | called. |
|
|
808 | |
|
|
809 | The return value is false if there are no more active watchers (which |
|
|
810 | usually means "all jobs done" or "deadlock"), and true in all other cases |
|
|
811 | (which usually means " you should call C<ev_run> again"). |
808 | |
812 | |
809 | Please note that an explicit C<ev_break> is usually better than |
813 | Please note that an explicit C<ev_break> is usually better than |
810 | relying on all watchers to be stopped when deciding when a program has |
814 | relying on all watchers to be stopped when deciding when a program has |
811 | finished (especially in interactive programs), but having a program |
815 | finished (especially in interactive programs), but having a program |
812 | that automatically loops as long as it has to and no longer by virtue |
816 | that automatically loops as long as it has to and no longer by virtue |
813 | of relying on its watchers stopping correctly, that is truly a thing of |
817 | of relying on its watchers stopping correctly, that is truly a thing of |
814 | beauty. |
818 | beauty. |
815 | |
819 | |
816 | This function is also I<mostly> exception-safe - you can break out of |
820 | This function is I<mostly> exception-safe - you can break out of a |
817 | a C<ev_run> call by calling C<longjmp> in a callback, throwing a C++ |
821 | C<ev_run> call by calling C<longjmp> in a callback, throwing a C++ |
818 | exception and so on. This does not decrement the C<ev_depth> value, nor |
822 | exception and so on. This does not decrement the C<ev_depth> value, nor |
819 | will it clear any outstanding C<EVBREAK_ONE> breaks. |
823 | will it clear any outstanding C<EVBREAK_ONE> breaks. |
820 | |
824 | |
821 | A flags value of C<EVRUN_NOWAIT> will look for new events, will handle |
825 | A flags value of C<EVRUN_NOWAIT> will look for new events, will handle |
822 | those events and any already outstanding ones, but will not wait and |
826 | those events and any already outstanding ones, but will not wait and |
… | |
… | |
1012 | invoke the actual watchers inside another context (another thread etc.). |
1016 | invoke the actual watchers inside another context (another thread etc.). |
1013 | |
1017 | |
1014 | If you want to reset the callback, use C<ev_invoke_pending> as new |
1018 | If you want to reset the callback, use C<ev_invoke_pending> as new |
1015 | callback. |
1019 | callback. |
1016 | |
1020 | |
1017 | =item ev_set_loop_release_cb (loop, void (*release)(EV_P), void (*acquire)(EV_P)) |
1021 | =item ev_set_loop_release_cb (loop, void (*release)(EV_P) throw (), void (*acquire)(EV_P) throw ()) |
1018 | |
1022 | |
1019 | Sometimes you want to share the same loop between multiple threads. This |
1023 | Sometimes you want to share the same loop between multiple threads. This |
1020 | can be done relatively simply by putting mutex_lock/unlock calls around |
1024 | can be done relatively simply by putting mutex_lock/unlock calls around |
1021 | each call to a libev function. |
1025 | each call to a libev function. |
1022 | |
1026 | |
1023 | However, C<ev_run> can run an indefinite time, so it is not feasible |
1027 | However, C<ev_run> can run an indefinite time, so it is not feasible |
1024 | to wait for it to return. One way around this is to wake up the event |
1028 | to wait for it to return. One way around this is to wake up the event |
1025 | loop via C<ev_break> and C<av_async_send>, another way is to set these |
1029 | loop via C<ev_break> and C<ev_async_send>, another way is to set these |
1026 | I<release> and I<acquire> callbacks on the loop. |
1030 | I<release> and I<acquire> callbacks on the loop. |
1027 | |
1031 | |
1028 | When set, then C<release> will be called just before the thread is |
1032 | When set, then C<release> will be called just before the thread is |
1029 | suspended waiting for new events, and C<acquire> is called just |
1033 | suspended waiting for new events, and C<acquire> is called just |
1030 | afterwards. |
1034 | afterwards. |
… | |
… | |
1170 | |
1174 | |
1171 | =item C<EV_PREPARE> |
1175 | =item C<EV_PREPARE> |
1172 | |
1176 | |
1173 | =item C<EV_CHECK> |
1177 | =item C<EV_CHECK> |
1174 | |
1178 | |
1175 | All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts |
1179 | All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts to |
1176 | to gather new events, and all C<ev_check> watchers are invoked just after |
1180 | gather new events, and all C<ev_check> watchers are queued (not invoked) |
1177 | C<ev_run> has gathered them, but before it invokes any callbacks for any |
1181 | just after C<ev_run> has gathered them, but before it queues any callbacks |
|
|
1182 | for any received events. That means C<ev_prepare> watchers are the last |
|
|
1183 | watchers invoked before the event loop sleeps or polls for new events, and |
|
|
1184 | C<ev_check> watchers will be invoked before any other watchers of the same |
|
|
1185 | or lower priority within an event loop iteration. |
|
|
1186 | |
1178 | received events. Callbacks of both watcher types can start and stop as |
1187 | Callbacks of both watcher types can start and stop as many watchers as |
1179 | many watchers as they want, and all of them will be taken into account |
1188 | they want, and all of them will be taken into account (for example, a |
1180 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
1189 | C<ev_prepare> watcher might start an idle watcher to keep C<ev_run> from |
1181 | C<ev_run> from blocking). |
1190 | blocking). |
1182 | |
1191 | |
1183 | =item C<EV_EMBED> |
1192 | =item C<EV_EMBED> |
1184 | |
1193 | |
1185 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
1194 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
1186 | |
1195 | |
… | |
… | |
1309 | |
1318 | |
1310 | =item callback ev_cb (ev_TYPE *watcher) |
1319 | =item callback ev_cb (ev_TYPE *watcher) |
1311 | |
1320 | |
1312 | Returns the callback currently set on the watcher. |
1321 | Returns the callback currently set on the watcher. |
1313 | |
1322 | |
1314 | =item ev_cb_set (ev_TYPE *watcher, callback) |
1323 | =item ev_set_cb (ev_TYPE *watcher, callback) |
1315 | |
1324 | |
1316 | Change the callback. You can change the callback at virtually any time |
1325 | Change the callback. You can change the callback at virtually any time |
1317 | (modulo threads). |
1326 | (modulo threads). |
1318 | |
1327 | |
1319 | =item ev_set_priority (ev_TYPE *watcher, int priority) |
1328 | =item ev_set_priority (ev_TYPE *watcher, int priority) |
… | |
… | |
1337 | or might not have been clamped to the valid range. |
1346 | or might not have been clamped to the valid range. |
1338 | |
1347 | |
1339 | The default priority used by watchers when no priority has been set is |
1348 | The default priority used by watchers when no priority has been set is |
1340 | always C<0>, which is supposed to not be too high and not be too low :). |
1349 | always C<0>, which is supposed to not be too high and not be too low :). |
1341 | |
1350 | |
1342 | See L<WATCHER PRIORITY MODELS>, below, for a more thorough treatment of |
1351 | See L</WATCHER PRIORITY MODELS>, below, for a more thorough treatment of |
1343 | priorities. |
1352 | priorities. |
1344 | |
1353 | |
1345 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
1354 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
1346 | |
1355 | |
1347 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
1356 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
… | |
… | |
1372 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
1381 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
1373 | functions that do not need a watcher. |
1382 | functions that do not need a watcher. |
1374 | |
1383 | |
1375 | =back |
1384 | =back |
1376 | |
1385 | |
1377 | See also the L<ASSOCIATING CUSTOM DATA WITH A WATCHER> and L<BUILDING YOUR |
1386 | See also the L</ASSOCIATING CUSTOM DATA WITH A WATCHER> and L</BUILDING YOUR |
1378 | OWN COMPOSITE WATCHERS> idioms. |
1387 | OWN COMPOSITE WATCHERS> idioms. |
1379 | |
1388 | |
1380 | =head2 WATCHER STATES |
1389 | =head2 WATCHER STATES |
1381 | |
1390 | |
1382 | There are various watcher states mentioned throughout this manual - |
1391 | There are various watcher states mentioned throughout this manual - |
… | |
… | |
1860 | |
1869 | |
1861 | In this case, it would be more efficient to leave the C<ev_timer> alone, |
1870 | In this case, it would be more efficient to leave the C<ev_timer> alone, |
1862 | but remember the time of last activity, and check for a real timeout only |
1871 | but remember the time of last activity, and check for a real timeout only |
1863 | within the callback: |
1872 | within the callback: |
1864 | |
1873 | |
|
|
1874 | ev_tstamp timeout = 60.; |
1865 | ev_tstamp last_activity; // time of last activity |
1875 | ev_tstamp last_activity; // time of last activity |
|
|
1876 | ev_timer timer; |
1866 | |
1877 | |
1867 | static void |
1878 | static void |
1868 | callback (EV_P_ ev_timer *w, int revents) |
1879 | callback (EV_P_ ev_timer *w, int revents) |
1869 | { |
1880 | { |
1870 | ev_tstamp now = ev_now (EV_A); |
1881 | // calculate when the timeout would happen |
1871 | ev_tstamp timeout = last_activity + 60.; |
1882 | ev_tstamp after = last_activity - ev_now (EV_A) + timeout; |
1872 | |
1883 | |
1873 | // if last_activity + 60. is older than now, we did time out |
1884 | // if negative, it means we the timeout already occurred |
1874 | if (timeout < now) |
1885 | if (after < 0.) |
1875 | { |
1886 | { |
1876 | // timeout occurred, take action |
1887 | // timeout occurred, take action |
1877 | } |
1888 | } |
1878 | else |
1889 | else |
1879 | { |
1890 | { |
1880 | // callback was invoked, but there was some activity, re-arm |
1891 | // callback was invoked, but there was some recent |
1881 | // the watcher to fire in last_activity + 60, which is |
1892 | // activity. simply restart the timer to time out |
1882 | // guaranteed to be in the future, so "again" is positive: |
1893 | // after "after" seconds, which is the earliest time |
1883 | w->repeat = timeout - now; |
1894 | // the timeout can occur. |
|
|
1895 | ev_timer_set (w, after, 0.); |
1884 | ev_timer_again (EV_A_ w); |
1896 | ev_timer_start (EV_A_ w); |
1885 | } |
1897 | } |
1886 | } |
1898 | } |
1887 | |
1899 | |
1888 | To summarise the callback: first calculate the real timeout (defined |
1900 | To summarise the callback: first calculate in how many seconds the |
1889 | as "60 seconds after the last activity"), then check if that time has |
1901 | timeout will occur (by calculating the absolute time when it would occur, |
1890 | been reached, which means something I<did>, in fact, time out. Otherwise |
1902 | C<last_activity + timeout>, and subtracting the current time, C<ev_now |
1891 | the callback was invoked too early (C<timeout> is in the future), so |
1903 | (EV_A)> from that). |
1892 | re-schedule the timer to fire at that future time, to see if maybe we have |
|
|
1893 | a timeout then. |
|
|
1894 | |
1904 | |
1895 | Note how C<ev_timer_again> is used, taking advantage of the |
1905 | If this value is negative, then we are already past the timeout, i.e. we |
1896 | C<ev_timer_again> optimisation when the timer is already running. |
1906 | timed out, and need to do whatever is needed in this case. |
|
|
1907 | |
|
|
1908 | Otherwise, we now the earliest time at which the timeout would trigger, |
|
|
1909 | and simply start the timer with this timeout value. |
|
|
1910 | |
|
|
1911 | In other words, each time the callback is invoked it will check whether |
|
|
1912 | the timeout occurred. If not, it will simply reschedule itself to check |
|
|
1913 | again at the earliest time it could time out. Rinse. Repeat. |
1897 | |
1914 | |
1898 | This scheme causes more callback invocations (about one every 60 seconds |
1915 | This scheme causes more callback invocations (about one every 60 seconds |
1899 | minus half the average time between activity), but virtually no calls to |
1916 | minus half the average time between activity), but virtually no calls to |
1900 | libev to change the timeout. |
1917 | libev to change the timeout. |
1901 | |
1918 | |
1902 | To start the timer, simply initialise the watcher and set C<last_activity> |
1919 | To start the machinery, simply initialise the watcher and set |
1903 | to the current time (meaning we just have some activity :), then call the |
1920 | C<last_activity> to the current time (meaning there was some activity just |
1904 | callback, which will "do the right thing" and start the timer: |
1921 | now), then call the callback, which will "do the right thing" and start |
|
|
1922 | the timer: |
1905 | |
1923 | |
|
|
1924 | last_activity = ev_now (EV_A); |
1906 | ev_init (timer, callback); |
1925 | ev_init (&timer, callback); |
1907 | last_activity = ev_now (loop); |
1926 | callback (EV_A_ &timer, 0); |
1908 | callback (loop, timer, EV_TIMER); |
|
|
1909 | |
1927 | |
1910 | And when there is some activity, simply store the current time in |
1928 | When there is some activity, simply store the current time in |
1911 | C<last_activity>, no libev calls at all: |
1929 | C<last_activity>, no libev calls at all: |
1912 | |
1930 | |
|
|
1931 | if (activity detected) |
1913 | last_activity = ev_now (loop); |
1932 | last_activity = ev_now (EV_A); |
|
|
1933 | |
|
|
1934 | When your timeout value changes, then the timeout can be changed by simply |
|
|
1935 | providing a new value, stopping the timer and calling the callback, which |
|
|
1936 | will again do the right thing (for example, time out immediately :). |
|
|
1937 | |
|
|
1938 | timeout = new_value; |
|
|
1939 | ev_timer_stop (EV_A_ &timer); |
|
|
1940 | callback (EV_A_ &timer, 0); |
1914 | |
1941 | |
1915 | This technique is slightly more complex, but in most cases where the |
1942 | This technique is slightly more complex, but in most cases where the |
1916 | time-out is unlikely to be triggered, much more efficient. |
1943 | time-out is unlikely to be triggered, much more efficient. |
1917 | |
|
|
1918 | Changing the timeout is trivial as well (if it isn't hard-coded in the |
|
|
1919 | callback :) - just change the timeout and invoke the callback, which will |
|
|
1920 | fix things for you. |
|
|
1921 | |
1944 | |
1922 | =item 4. Wee, just use a double-linked list for your timeouts. |
1945 | =item 4. Wee, just use a double-linked list for your timeouts. |
1923 | |
1946 | |
1924 | If there is not one request, but many thousands (millions...), all |
1947 | If there is not one request, but many thousands (millions...), all |
1925 | employing some kind of timeout with the same timeout value, then one can |
1948 | employing some kind of timeout with the same timeout value, then one can |
… | |
… | |
1958 | |
1981 | |
1959 | If you ask a timer to call your callback after three seconds, then |
1982 | If you ask a timer to call your callback after three seconds, then |
1960 | you expect it to be invoked after three seconds - but of course, this |
1983 | you expect it to be invoked after three seconds - but of course, this |
1961 | cannot be guaranteed to infinite precision. Less obviously, it cannot be |
1984 | cannot be guaranteed to infinite precision. Less obviously, it cannot be |
1962 | guaranteed to any precision by libev - imagine somebody suspending the |
1985 | guaranteed to any precision by libev - imagine somebody suspending the |
1963 | process a STOP signal for a few hours for example. |
1986 | process with a STOP signal for a few hours for example. |
1964 | |
1987 | |
1965 | So, libev tries to invoke your callback as soon as possible I<after> the |
1988 | So, libev tries to invoke your callback as soon as possible I<after> the |
1966 | delay has occurred, but cannot guarantee this. |
1989 | delay has occurred, but cannot guarantee this. |
1967 | |
1990 | |
1968 | A less obvious failure mode is calling your callback too early: many event |
1991 | A less obvious failure mode is calling your callback too early: many event |
… | |
… | |
2094 | keep up with the timer (because it takes longer than those 10 seconds to |
2117 | keep up with the timer (because it takes longer than those 10 seconds to |
2095 | do stuff) the timer will not fire more than once per event loop iteration. |
2118 | do stuff) the timer will not fire more than once per event loop iteration. |
2096 | |
2119 | |
2097 | =item ev_timer_again (loop, ev_timer *) |
2120 | =item ev_timer_again (loop, ev_timer *) |
2098 | |
2121 | |
2099 | This will act as if the timer timed out and restarts it again if it is |
2122 | This will act as if the timer timed out, and restarts it again if it is |
2100 | repeating. The exact semantics are: |
2123 | repeating. It basically works like calling C<ev_timer_stop>, updating the |
|
|
2124 | timeout to the C<repeat> value and calling C<ev_timer_start>. |
2101 | |
2125 | |
|
|
2126 | The exact semantics are as in the following rules, all of which will be |
|
|
2127 | applied to the watcher: |
|
|
2128 | |
|
|
2129 | =over 4 |
|
|
2130 | |
2102 | If the timer is pending, its pending status is cleared. |
2131 | =item If the timer is pending, the pending status is always cleared. |
2103 | |
2132 | |
2104 | If the timer is started but non-repeating, stop it (as if it timed out). |
2133 | =item If the timer is started but non-repeating, stop it (as if it timed |
|
|
2134 | out, without invoking it). |
2105 | |
2135 | |
2106 | If the timer is repeating, either start it if necessary (with the |
2136 | =item If the timer is repeating, make the C<repeat> value the new timeout |
2107 | C<repeat> value), or reset the running timer to the C<repeat> value. |
2137 | and start the timer, if necessary. |
2108 | |
2138 | |
|
|
2139 | =back |
|
|
2140 | |
2109 | This sounds a bit complicated, see L<Be smart about timeouts>, above, for a |
2141 | This sounds a bit complicated, see L</Be smart about timeouts>, above, for a |
2110 | usage example. |
2142 | usage example. |
2111 | |
2143 | |
2112 | =item ev_tstamp ev_timer_remaining (loop, ev_timer *) |
2144 | =item ev_tstamp ev_timer_remaining (loop, ev_timer *) |
2113 | |
2145 | |
2114 | Returns the remaining time until a timer fires. If the timer is active, |
2146 | Returns the remaining time until a timer fires. If the timer is active, |
… | |
… | |
2815 | Apart from keeping your process non-blocking (which is a useful |
2847 | Apart from keeping your process non-blocking (which is a useful |
2816 | effect on its own sometimes), idle watchers are a good place to do |
2848 | effect on its own sometimes), idle watchers are a good place to do |
2817 | "pseudo-background processing", or delay processing stuff to after the |
2849 | "pseudo-background processing", or delay processing stuff to after the |
2818 | event loop has handled all outstanding events. |
2850 | event loop has handled all outstanding events. |
2819 | |
2851 | |
|
|
2852 | =head3 Abusing an C<ev_idle> watcher for its side-effect |
|
|
2853 | |
|
|
2854 | As long as there is at least one active idle watcher, libev will never |
|
|
2855 | sleep unnecessarily. Or in other words, it will loop as fast as possible. |
|
|
2856 | For this to work, the idle watcher doesn't need to be invoked at all - the |
|
|
2857 | lowest priority will do. |
|
|
2858 | |
|
|
2859 | This mode of operation can be useful together with an C<ev_check> watcher, |
|
|
2860 | to do something on each event loop iteration - for example to balance load |
|
|
2861 | between different connections. |
|
|
2862 | |
|
|
2863 | See L</Abusing an ev_check watcher for its side-effect> for a longer |
|
|
2864 | example. |
|
|
2865 | |
2820 | =head3 Watcher-Specific Functions and Data Members |
2866 | =head3 Watcher-Specific Functions and Data Members |
2821 | |
2867 | |
2822 | =over 4 |
2868 | =over 4 |
2823 | |
2869 | |
2824 | =item ev_idle_init (ev_idle *, callback) |
2870 | =item ev_idle_init (ev_idle *, callback) |
… | |
… | |
2835 | callback, free it. Also, use no error checking, as usual. |
2881 | callback, free it. Also, use no error checking, as usual. |
2836 | |
2882 | |
2837 | static void |
2883 | static void |
2838 | idle_cb (struct ev_loop *loop, ev_idle *w, int revents) |
2884 | idle_cb (struct ev_loop *loop, ev_idle *w, int revents) |
2839 | { |
2885 | { |
|
|
2886 | // stop the watcher |
|
|
2887 | ev_idle_stop (loop, w); |
|
|
2888 | |
|
|
2889 | // now we can free it |
2840 | free (w); |
2890 | free (w); |
|
|
2891 | |
2841 | // now do something you wanted to do when the program has |
2892 | // now do something you wanted to do when the program has |
2842 | // no longer anything immediate to do. |
2893 | // no longer anything immediate to do. |
2843 | } |
2894 | } |
2844 | |
2895 | |
2845 | ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
2896 | ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
… | |
… | |
2847 | ev_idle_start (loop, idle_watcher); |
2898 | ev_idle_start (loop, idle_watcher); |
2848 | |
2899 | |
2849 | |
2900 | |
2850 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop! |
2901 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop! |
2851 | |
2902 | |
2852 | Prepare and check watchers are usually (but not always) used in pairs: |
2903 | Prepare and check watchers are often (but not always) used in pairs: |
2853 | prepare watchers get invoked before the process blocks and check watchers |
2904 | prepare watchers get invoked before the process blocks and check watchers |
2854 | afterwards. |
2905 | afterwards. |
2855 | |
2906 | |
2856 | You I<must not> call C<ev_run> or similar functions that enter |
2907 | You I<must not> call C<ev_run> or similar functions that enter |
2857 | the current event loop from either C<ev_prepare> or C<ev_check> |
2908 | the current event loop from either C<ev_prepare> or C<ev_check> |
… | |
… | |
2885 | with priority higher than or equal to the event loop and one coroutine |
2936 | with priority higher than or equal to the event loop and one coroutine |
2886 | of lower priority, but only once, using idle watchers to keep the event |
2937 | of lower priority, but only once, using idle watchers to keep the event |
2887 | loop from blocking if lower-priority coroutines are active, thus mapping |
2938 | loop from blocking if lower-priority coroutines are active, thus mapping |
2888 | low-priority coroutines to idle/background tasks). |
2939 | low-priority coroutines to idle/background tasks). |
2889 | |
2940 | |
2890 | It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>) |
2941 | When used for this purpose, it is recommended to give C<ev_check> watchers |
2891 | priority, to ensure that they are being run before any other watchers |
2942 | highest (C<EV_MAXPRI>) priority, to ensure that they are being run before |
2892 | after the poll (this doesn't matter for C<ev_prepare> watchers). |
2943 | any other watchers after the poll (this doesn't matter for C<ev_prepare> |
|
|
2944 | watchers). |
2893 | |
2945 | |
2894 | Also, C<ev_check> watchers (and C<ev_prepare> watchers, too) should not |
2946 | Also, C<ev_check> watchers (and C<ev_prepare> watchers, too) should not |
2895 | activate ("feed") events into libev. While libev fully supports this, they |
2947 | activate ("feed") events into libev. While libev fully supports this, they |
2896 | might get executed before other C<ev_check> watchers did their job. As |
2948 | might get executed before other C<ev_check> watchers did their job. As |
2897 | C<ev_check> watchers are often used to embed other (non-libev) event |
2949 | C<ev_check> watchers are often used to embed other (non-libev) event |
2898 | loops those other event loops might be in an unusable state until their |
2950 | loops those other event loops might be in an unusable state until their |
2899 | C<ev_check> watcher ran (always remind yourself to coexist peacefully with |
2951 | C<ev_check> watcher ran (always remind yourself to coexist peacefully with |
2900 | others). |
2952 | others). |
|
|
2953 | |
|
|
2954 | =head3 Abusing an C<ev_check> watcher for its side-effect |
|
|
2955 | |
|
|
2956 | C<ev_check> (and less often also C<ev_prepare>) watchers can also be |
|
|
2957 | useful because they are called once per event loop iteration. For |
|
|
2958 | example, if you want to handle a large number of connections fairly, you |
|
|
2959 | normally only do a bit of work for each active connection, and if there |
|
|
2960 | is more work to do, you wait for the next event loop iteration, so other |
|
|
2961 | connections have a chance of making progress. |
|
|
2962 | |
|
|
2963 | Using an C<ev_check> watcher is almost enough: it will be called on the |
|
|
2964 | next event loop iteration. However, that isn't as soon as possible - |
|
|
2965 | without external events, your C<ev_check> watcher will not be invoked. |
|
|
2966 | |
|
|
2967 | |
|
|
2968 | This is where C<ev_idle> watchers come in handy - all you need is a |
|
|
2969 | single global idle watcher that is active as long as you have one active |
|
|
2970 | C<ev_check> watcher. The C<ev_idle> watcher makes sure the event loop |
|
|
2971 | will not sleep, and the C<ev_check> watcher makes sure a callback gets |
|
|
2972 | invoked. Neither watcher alone can do that. |
2901 | |
2973 | |
2902 | =head3 Watcher-Specific Functions and Data Members |
2974 | =head3 Watcher-Specific Functions and Data Members |
2903 | |
2975 | |
2904 | =over 4 |
2976 | =over 4 |
2905 | |
2977 | |
… | |
… | |
3286 | it by calling C<ev_async_send>, which is thread- and signal safe. |
3358 | it by calling C<ev_async_send>, which is thread- and signal safe. |
3287 | |
3359 | |
3288 | This functionality is very similar to C<ev_signal> watchers, as signals, |
3360 | This functionality is very similar to C<ev_signal> watchers, as signals, |
3289 | too, are asynchronous in nature, and signals, too, will be compressed |
3361 | too, are asynchronous in nature, and signals, too, will be compressed |
3290 | (i.e. the number of callback invocations may be less than the number of |
3362 | (i.e. the number of callback invocations may be less than the number of |
3291 | C<ev_async_sent> calls). In fact, you could use signal watchers as a kind |
3363 | C<ev_async_send> calls). In fact, you could use signal watchers as a kind |
3292 | of "global async watchers" by using a watcher on an otherwise unused |
3364 | of "global async watchers" by using a watcher on an otherwise unused |
3293 | signal, and C<ev_feed_signal> to signal this watcher from another thread, |
3365 | signal, and C<ev_feed_signal> to signal this watcher from another thread, |
3294 | even without knowing which loop owns the signal. |
3366 | even without knowing which loop owns the signal. |
3295 | |
3367 | |
3296 | =head3 Queueing |
3368 | =head3 Queueing |
… | |
… | |
3473 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
3545 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
3474 | |
3546 | |
3475 | =item ev_feed_fd_event (loop, int fd, int revents) |
3547 | =item ev_feed_fd_event (loop, int fd, int revents) |
3476 | |
3548 | |
3477 | Feed an event on the given fd, as if a file descriptor backend detected |
3549 | Feed an event on the given fd, as if a file descriptor backend detected |
3478 | the given events it. |
3550 | the given events. |
3479 | |
3551 | |
3480 | =item ev_feed_signal_event (loop, int signum) |
3552 | =item ev_feed_signal_event (loop, int signum) |
3481 | |
3553 | |
3482 | Feed an event as if the given signal occurred. See also C<ev_feed_signal>, |
3554 | Feed an event as if the given signal occurred. See also C<ev_feed_signal>, |
3483 | which is async-safe. |
3555 | which is async-safe. |
… | |
… | |
3557 | { |
3629 | { |
3558 | struct my_biggy big = (struct my_biggy *) |
3630 | struct my_biggy big = (struct my_biggy *) |
3559 | (((char *)w) - offsetof (struct my_biggy, t2)); |
3631 | (((char *)w) - offsetof (struct my_biggy, t2)); |
3560 | } |
3632 | } |
3561 | |
3633 | |
|
|
3634 | =head2 AVOIDING FINISHING BEFORE RETURNING |
|
|
3635 | |
|
|
3636 | Often you have structures like this in event-based programs: |
|
|
3637 | |
|
|
3638 | callback () |
|
|
3639 | { |
|
|
3640 | free (request); |
|
|
3641 | } |
|
|
3642 | |
|
|
3643 | request = start_new_request (..., callback); |
|
|
3644 | |
|
|
3645 | The intent is to start some "lengthy" operation. The C<request> could be |
|
|
3646 | used to cancel the operation, or do other things with it. |
|
|
3647 | |
|
|
3648 | It's not uncommon to have code paths in C<start_new_request> that |
|
|
3649 | immediately invoke the callback, for example, to report errors. Or you add |
|
|
3650 | some caching layer that finds that it can skip the lengthy aspects of the |
|
|
3651 | operation and simply invoke the callback with the result. |
|
|
3652 | |
|
|
3653 | The problem here is that this will happen I<before> C<start_new_request> |
|
|
3654 | has returned, so C<request> is not set. |
|
|
3655 | |
|
|
3656 | Even if you pass the request by some safer means to the callback, you |
|
|
3657 | might want to do something to the request after starting it, such as |
|
|
3658 | canceling it, which probably isn't working so well when the callback has |
|
|
3659 | already been invoked. |
|
|
3660 | |
|
|
3661 | A common way around all these issues is to make sure that |
|
|
3662 | C<start_new_request> I<always> returns before the callback is invoked. If |
|
|
3663 | C<start_new_request> immediately knows the result, it can artificially |
|
|
3664 | delay invoking the callback by e.g. using a C<prepare> or C<idle> watcher |
|
|
3665 | for example, or more sneakily, by reusing an existing (stopped) watcher |
|
|
3666 | and pushing it into the pending queue: |
|
|
3667 | |
|
|
3668 | ev_set_cb (watcher, callback); |
|
|
3669 | ev_feed_event (EV_A_ watcher, 0); |
|
|
3670 | |
|
|
3671 | This way, C<start_new_request> can safely return before the callback is |
|
|
3672 | invoked, while not delaying callback invocation too much. |
|
|
3673 | |
3562 | =head2 MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS |
3674 | =head2 MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS |
3563 | |
3675 | |
3564 | Often (especially in GUI toolkits) there are places where you have |
3676 | Often (especially in GUI toolkits) there are places where you have |
3565 | I<modal> interaction, which is most easily implemented by recursively |
3677 | I<modal> interaction, which is most easily implemented by recursively |
3566 | invoking C<ev_run>. |
3678 | invoking C<ev_run>. |
… | |
… | |
3579 | int exit_main_loop = 0; |
3691 | int exit_main_loop = 0; |
3580 | |
3692 | |
3581 | while (!exit_main_loop) |
3693 | while (!exit_main_loop) |
3582 | ev_run (EV_DEFAULT_ EVRUN_ONCE); |
3694 | ev_run (EV_DEFAULT_ EVRUN_ONCE); |
3583 | |
3695 | |
3584 | // in a model watcher |
3696 | // in a modal watcher |
3585 | int exit_nested_loop = 0; |
3697 | int exit_nested_loop = 0; |
3586 | |
3698 | |
3587 | while (!exit_nested_loop) |
3699 | while (!exit_nested_loop) |
3588 | ev_run (EV_A_ EVRUN_ONCE); |
3700 | ev_run (EV_A_ EVRUN_ONCE); |
3589 | |
3701 | |
… | |
… | |
3763 | called): |
3875 | called): |
3764 | |
3876 | |
3765 | void |
3877 | void |
3766 | wait_for_event (ev_watcher *w) |
3878 | wait_for_event (ev_watcher *w) |
3767 | { |
3879 | { |
3768 | ev_cb_set (w) = current_coro; |
3880 | ev_set_cb (w, current_coro); |
3769 | switch_to (libev_coro); |
3881 | switch_to (libev_coro); |
3770 | } |
3882 | } |
3771 | |
3883 | |
3772 | That basically suspends the coroutine inside C<wait_for_event> and |
3884 | That basically suspends the coroutine inside C<wait_for_event> and |
3773 | continues the libev coroutine, which, when appropriate, switches back to |
3885 | continues the libev coroutine, which, when appropriate, switches back to |
3774 | this or any other coroutine. I am sure if you sue this your own :) |
3886 | this or any other coroutine. |
3775 | |
3887 | |
3776 | You can do similar tricks if you have, say, threads with an event queue - |
3888 | You can do similar tricks if you have, say, threads with an event queue - |
3777 | instead of storing a coroutine, you store the queue object and instead of |
3889 | instead of storing a coroutine, you store the queue object and instead of |
3778 | switching to a coroutine, you push the watcher onto the queue and notify |
3890 | switching to a coroutine, you push the watcher onto the queue and notify |
3779 | any waiters. |
3891 | any waiters. |
3780 | |
3892 | |
3781 | To embed libev, see L<EMBEDDING>, but in short, it's easiest to create two |
3893 | To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two |
3782 | files, F<my_ev.h> and F<my_ev.c> that include the respective libev files: |
3894 | files, F<my_ev.h> and F<my_ev.c> that include the respective libev files: |
3783 | |
3895 | |
3784 | // my_ev.h |
3896 | // my_ev.h |
3785 | #define EV_CB_DECLARE(type) struct my_coro *cb; |
3897 | #define EV_CB_DECLARE(type) struct my_coro *cb; |
3786 | #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb); |
3898 | #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb); |
… | |
… | |
3829 | to use the libev header file and library. |
3941 | to use the libev header file and library. |
3830 | |
3942 | |
3831 | =back |
3943 | =back |
3832 | |
3944 | |
3833 | =head1 C++ SUPPORT |
3945 | =head1 C++ SUPPORT |
|
|
3946 | |
|
|
3947 | =head2 C API |
|
|
3948 | |
|
|
3949 | The normal C API should work fine when used from C++: both ev.h and the |
|
|
3950 | libev sources can be compiled as C++. Therefore, code that uses the C API |
|
|
3951 | will work fine. |
|
|
3952 | |
|
|
3953 | Proper exception specifications might have to be added to callbacks passed |
|
|
3954 | to libev: exceptions may be thrown only from watcher callbacks, all |
|
|
3955 | other callbacks (allocator, syserr, loop acquire/release and periodic |
|
|
3956 | reschedule callbacks) must not throw exceptions, and might need a C<throw |
|
|
3957 | ()> specification. If you have code that needs to be compiled as both C |
|
|
3958 | and C++ you can use the C<EV_THROW> macro for this: |
|
|
3959 | |
|
|
3960 | static void |
|
|
3961 | fatal_error (const char *msg) EV_THROW |
|
|
3962 | { |
|
|
3963 | perror (msg); |
|
|
3964 | abort (); |
|
|
3965 | } |
|
|
3966 | |
|
|
3967 | ... |
|
|
3968 | ev_set_syserr_cb (fatal_error); |
|
|
3969 | |
|
|
3970 | The only API functions that can currently throw exceptions are C<ev_run>, |
|
|
3971 | C<ev_invoke>, C<ev_invoke_pending> and C<ev_loop_destroy> (the latter |
|
|
3972 | because it runs cleanup watchers). |
|
|
3973 | |
|
|
3974 | Throwing exceptions in watcher callbacks is only supported if libev itself |
|
|
3975 | is compiled with a C++ compiler or your C and C++ environments allow |
|
|
3976 | throwing exceptions through C libraries (most do). |
|
|
3977 | |
|
|
3978 | =head2 C++ API |
3834 | |
3979 | |
3835 | Libev comes with some simplistic wrapper classes for C++ that mainly allow |
3980 | Libev comes with some simplistic wrapper classes for C++ that mainly allow |
3836 | you to use some convenience methods to start/stop watchers and also change |
3981 | you to use some convenience methods to start/stop watchers and also change |
3837 | the callback model to a model using method callbacks on objects. |
3982 | the callback model to a model using method callbacks on objects. |
3838 | |
3983 | |
… | |
… | |
3854 | with C<operator ()> can be used as callbacks. Other types should be easy |
3999 | with C<operator ()> can be used as callbacks. Other types should be easy |
3855 | to add as long as they only need one additional pointer for context. If |
4000 | to add as long as they only need one additional pointer for context. If |
3856 | you need support for other types of functors please contact the author |
4001 | you need support for other types of functors please contact the author |
3857 | (preferably after implementing it). |
4002 | (preferably after implementing it). |
3858 | |
4003 | |
|
|
4004 | For all this to work, your C++ compiler either has to use the same calling |
|
|
4005 | conventions as your C compiler (for static member functions), or you have |
|
|
4006 | to embed libev and compile libev itself as C++. |
|
|
4007 | |
3859 | Here is a list of things available in the C<ev> namespace: |
4008 | Here is a list of things available in the C<ev> namespace: |
3860 | |
4009 | |
3861 | =over 4 |
4010 | =over 4 |
3862 | |
4011 | |
3863 | =item C<ev::READ>, C<ev::WRITE> etc. |
4012 | =item C<ev::READ>, C<ev::WRITE> etc. |
… | |
… | |
3872 | =item C<ev::io>, C<ev::timer>, C<ev::periodic>, C<ev::idle>, C<ev::sig> etc. |
4021 | =item C<ev::io>, C<ev::timer>, C<ev::periodic>, C<ev::idle>, C<ev::sig> etc. |
3873 | |
4022 | |
3874 | For each C<ev_TYPE> watcher in F<ev.h> there is a corresponding class of |
4023 | For each C<ev_TYPE> watcher in F<ev.h> there is a corresponding class of |
3875 | the same name in the C<ev> namespace, with the exception of C<ev_signal> |
4024 | the same name in the C<ev> namespace, with the exception of C<ev_signal> |
3876 | which is called C<ev::sig> to avoid clashes with the C<signal> macro |
4025 | which is called C<ev::sig> to avoid clashes with the C<signal> macro |
3877 | defines by many implementations. |
4026 | defined by many implementations. |
3878 | |
4027 | |
3879 | All of those classes have these methods: |
4028 | All of those classes have these methods: |
3880 | |
4029 | |
3881 | =over 4 |
4030 | =over 4 |
3882 | |
4031 | |
… | |
… | |
3972 | Associates a different C<struct ev_loop> with this watcher. You can only |
4121 | Associates a different C<struct ev_loop> with this watcher. You can only |
3973 | do this when the watcher is inactive (and not pending either). |
4122 | do this when the watcher is inactive (and not pending either). |
3974 | |
4123 | |
3975 | =item w->set ([arguments]) |
4124 | =item w->set ([arguments]) |
3976 | |
4125 | |
3977 | Basically the same as C<ev_TYPE_set>, with the same arguments. Either this |
4126 | Basically the same as C<ev_TYPE_set> (except for C<ev::embed> watchers>), |
3978 | method or a suitable start method must be called at least once. Unlike the |
4127 | with the same arguments. Either this method or a suitable start method |
3979 | C counterpart, an active watcher gets automatically stopped and restarted |
4128 | must be called at least once. Unlike the C counterpart, an active watcher |
3980 | when reconfiguring it with this method. |
4129 | gets automatically stopped and restarted when reconfiguring it with this |
|
|
4130 | method. |
|
|
4131 | |
|
|
4132 | For C<ev::embed> watchers this method is called C<set_embed>, to avoid |
|
|
4133 | clashing with the C<set (loop)> method. |
3981 | |
4134 | |
3982 | =item w->start () |
4135 | =item w->start () |
3983 | |
4136 | |
3984 | Starts the watcher. Note that there is no C<loop> argument, as the |
4137 | Starts the watcher. Note that there is no C<loop> argument, as the |
3985 | constructor already stores the event loop. |
4138 | constructor already stores the event loop. |
… | |
… | |
4088 | =item Lua |
4241 | =item Lua |
4089 | |
4242 | |
4090 | Brian Maher has written a partial interface to libev for lua (at the |
4243 | Brian Maher has written a partial interface to libev for lua (at the |
4091 | time of this writing, only C<ev_io> and C<ev_timer>), to be found at |
4244 | time of this writing, only C<ev_io> and C<ev_timer>), to be found at |
4092 | L<http://github.com/brimworks/lua-ev>. |
4245 | L<http://github.com/brimworks/lua-ev>. |
|
|
4246 | |
|
|
4247 | =item Javascript |
|
|
4248 | |
|
|
4249 | Node.js (L<http://nodejs.org>) uses libev as the underlying event library. |
|
|
4250 | |
|
|
4251 | =item Others |
|
|
4252 | |
|
|
4253 | There are others, and I stopped counting. |
4093 | |
4254 | |
4094 | =back |
4255 | =back |
4095 | |
4256 | |
4096 | |
4257 | |
4097 | =head1 MACRO MAGIC |
4258 | =head1 MACRO MAGIC |
… | |
… | |
4396 | |
4557 | |
4397 | If programs implement their own fd to handle mapping on win32, then this |
4558 | If programs implement their own fd to handle mapping on win32, then this |
4398 | macro can be used to override the C<close> function, useful to unregister |
4559 | macro can be used to override the C<close> function, useful to unregister |
4399 | file descriptors again. Note that the replacement function has to close |
4560 | file descriptors again. Note that the replacement function has to close |
4400 | the underlying OS handle. |
4561 | the underlying OS handle. |
|
|
4562 | |
|
|
4563 | =item EV_USE_WSASOCKET |
|
|
4564 | |
|
|
4565 | If defined to be C<1>, libev will use C<WSASocket> to create its internal |
|
|
4566 | communication socket, which works better in some environments. Otherwise, |
|
|
4567 | the normal C<socket> function will be used, which works better in other |
|
|
4568 | environments. |
4401 | |
4569 | |
4402 | =item EV_USE_POLL |
4570 | =item EV_USE_POLL |
4403 | |
4571 | |
4404 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
4572 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
4405 | backend. Otherwise it will be enabled on non-win32 platforms. It |
4573 | backend. Otherwise it will be enabled on non-win32 platforms. It |
… | |
… | |
4441 | If defined to be C<1>, libev will compile in support for the Linux inotify |
4609 | If defined to be C<1>, libev will compile in support for the Linux inotify |
4442 | interface to speed up C<ev_stat> watchers. Its actual availability will |
4610 | interface to speed up C<ev_stat> watchers. Its actual availability will |
4443 | be detected at runtime. If undefined, it will be enabled if the headers |
4611 | be detected at runtime. If undefined, it will be enabled if the headers |
4444 | indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4612 | indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4445 | |
4613 | |
|
|
4614 | =item EV_NO_SMP |
|
|
4615 | |
|
|
4616 | If defined to be C<1>, libev will assume that memory is always coherent |
|
|
4617 | between threads, that is, threads can be used, but threads never run on |
|
|
4618 | different cpus (or different cpu cores). This reduces dependencies |
|
|
4619 | and makes libev faster. |
|
|
4620 | |
|
|
4621 | =item EV_NO_THREADS |
|
|
4622 | |
|
|
4623 | If defined to be C<1>, libev will assume that it will never be called |
|
|
4624 | from different threads, which is a stronger assumption than C<EV_NO_SMP>, |
|
|
4625 | above. This reduces dependencies and makes libev faster. |
|
|
4626 | |
4446 | =item EV_ATOMIC_T |
4627 | =item EV_ATOMIC_T |
4447 | |
4628 | |
4448 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
4629 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
4449 | access is atomic and serialised with respect to other threads or signal |
4630 | access is atomic with respect to other threads or signal contexts. No |
4450 | contexts. No such type is easily found in the C language, so you can |
4631 | such type is easily found in the C language, so you can provide your own |
4451 | provide your own type that you know is safe for your purposes. It is used |
4632 | type that you know is safe for your purposes. It is used both for signal |
4452 | both for signal handler "locking" as well as for signal and thread safety |
4633 | handler "locking" as well as for signal and thread safety in C<ev_async> |
4453 | in C<ev_async> watchers. |
4634 | watchers. |
4454 | |
4635 | |
4455 | In the absence of this define, libev will use C<sig_atomic_t volatile> |
4636 | In the absence of this define, libev will use C<sig_atomic_t volatile> |
4456 | (from F<signal.h>), which is usually good enough on most platforms, |
4637 | (from F<signal.h>), which is usually good enough on most platforms. |
4457 | although strictly speaking using a type that also implies a memory fence |
|
|
4458 | is required. |
|
|
4459 | |
4638 | |
4460 | =item EV_H (h) |
4639 | =item EV_H (h) |
4461 | |
4640 | |
4462 | The name of the F<ev.h> header file used to include it. The default if |
4641 | The name of the F<ev.h> header file used to include it. The default if |
4463 | undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be |
4642 | undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be |
… | |
… | |
4536 | #define EV_USE_POLL 1 |
4715 | #define EV_USE_POLL 1 |
4537 | #define EV_CHILD_ENABLE 1 |
4716 | #define EV_CHILD_ENABLE 1 |
4538 | #define EV_ASYNC_ENABLE 1 |
4717 | #define EV_ASYNC_ENABLE 1 |
4539 | |
4718 | |
4540 | The actual value is a bitset, it can be a combination of the following |
4719 | The actual value is a bitset, it can be a combination of the following |
4541 | values: |
4720 | values (by default, all of these are enabled): |
4542 | |
4721 | |
4543 | =over 4 |
4722 | =over 4 |
4544 | |
4723 | |
4545 | =item C<1> - faster/larger code |
4724 | =item C<1> - faster/larger code |
4546 | |
4725 | |
… | |
… | |
4550 | code size by roughly 30% on amd64). |
4729 | code size by roughly 30% on amd64). |
4551 | |
4730 | |
4552 | When optimising for size, use of compiler flags such as C<-Os> with |
4731 | When optimising for size, use of compiler flags such as C<-Os> with |
4553 | gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of |
4732 | gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of |
4554 | assertions. |
4733 | assertions. |
|
|
4734 | |
|
|
4735 | The default is off when C<__OPTIMIZE_SIZE__> is defined by your compiler |
|
|
4736 | (e.g. gcc with C<-Os>). |
4555 | |
4737 | |
4556 | =item C<2> - faster/larger data structures |
4738 | =item C<2> - faster/larger data structures |
4557 | |
4739 | |
4558 | Replaces the small 2-heap for timer management by a faster 4-heap, larger |
4740 | Replaces the small 2-heap for timer management by a faster 4-heap, larger |
4559 | hash table sizes and so on. This will usually further increase code size |
4741 | hash table sizes and so on. This will usually further increase code size |
4560 | and can additionally have an effect on the size of data structures at |
4742 | and can additionally have an effect on the size of data structures at |
4561 | runtime. |
4743 | runtime. |
4562 | |
4744 | |
|
|
4745 | The default is off when C<__OPTIMIZE_SIZE__> is defined by your compiler |
|
|
4746 | (e.g. gcc with C<-Os>). |
|
|
4747 | |
4563 | =item C<4> - full API configuration |
4748 | =item C<4> - full API configuration |
4564 | |
4749 | |
4565 | This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and |
4750 | This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and |
4566 | enables multiplicity (C<EV_MULTIPLICITY>=1). |
4751 | enables multiplicity (C<EV_MULTIPLICITY>=1). |
4567 | |
4752 | |
… | |
… | |
4597 | |
4782 | |
4598 | With an intelligent-enough linker (gcc+binutils are intelligent enough |
4783 | With an intelligent-enough linker (gcc+binutils are intelligent enough |
4599 | when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by |
4784 | when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by |
4600 | your program might be left out as well - a binary starting a timer and an |
4785 | your program might be left out as well - a binary starting a timer and an |
4601 | I/O watcher then might come out at only 5Kb. |
4786 | I/O watcher then might come out at only 5Kb. |
|
|
4787 | |
|
|
4788 | =item EV_API_STATIC |
|
|
4789 | |
|
|
4790 | If this symbol is defined (by default it is not), then all identifiers |
|
|
4791 | will have static linkage. This means that libev will not export any |
|
|
4792 | identifiers, and you cannot link against libev anymore. This can be useful |
|
|
4793 | when you embed libev, only want to use libev functions in a single file, |
|
|
4794 | and do not want its identifiers to be visible. |
|
|
4795 | |
|
|
4796 | To use this, define C<EV_API_STATIC> and include F<ev.c> in the file that |
|
|
4797 | wants to use libev. |
|
|
4798 | |
|
|
4799 | This option only works when libev is compiled with a C compiler, as C++ |
|
|
4800 | doesn't support the required declaration syntax. |
4602 | |
4801 | |
4603 | =item EV_AVOID_STDIO |
4802 | =item EV_AVOID_STDIO |
4604 | |
4803 | |
4605 | If this is set to C<1> at compiletime, then libev will avoid using stdio |
4804 | If this is set to C<1> at compiletime, then libev will avoid using stdio |
4606 | functions (printf, scanf, perror etc.). This will increase the code size |
4805 | functions (printf, scanf, perror etc.). This will increase the code size |
… | |
… | |
4811 | default loop and triggering an C<ev_async> watcher from the default loop |
5010 | default loop and triggering an C<ev_async> watcher from the default loop |
4812 | watcher callback into the event loop interested in the signal. |
5011 | watcher callback into the event loop interested in the signal. |
4813 | |
5012 | |
4814 | =back |
5013 | =back |
4815 | |
5014 | |
4816 | See also L<THREAD LOCKING EXAMPLE>. |
5015 | See also L</THREAD LOCKING EXAMPLE>. |
4817 | |
5016 | |
4818 | =head3 COROUTINES |
5017 | =head3 COROUTINES |
4819 | |
5018 | |
4820 | Libev is very accommodating to coroutines ("cooperative threads"): |
5019 | Libev is very accommodating to coroutines ("cooperative threads"): |
4821 | libev fully supports nesting calls to its functions from different |
5020 | libev fully supports nesting calls to its functions from different |
… | |
… | |
5227 | =over 4 |
5426 | =over 4 |
5228 | |
5427 | |
5229 | =item C<EV_COMPAT3> backwards compatibility mechanism |
5428 | =item C<EV_COMPAT3> backwards compatibility mechanism |
5230 | |
5429 | |
5231 | The backward compatibility mechanism can be controlled by |
5430 | The backward compatibility mechanism can be controlled by |
5232 | C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING> |
5431 | C<EV_COMPAT3>. See L</PREPROCESSOR SYMBOLS/MACROS> in the L</EMBEDDING> |
5233 | section. |
5432 | section. |
5234 | |
5433 | |
5235 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
5434 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
5236 | |
5435 | |
5237 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
5436 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
… | |
… | |
5280 | =over 4 |
5479 | =over 4 |
5281 | |
5480 | |
5282 | =item active |
5481 | =item active |
5283 | |
5482 | |
5284 | A watcher is active as long as it has been started and not yet stopped. |
5483 | A watcher is active as long as it has been started and not yet stopped. |
5285 | See L<WATCHER STATES> for details. |
5484 | See L</WATCHER STATES> for details. |
5286 | |
5485 | |
5287 | =item application |
5486 | =item application |
5288 | |
5487 | |
5289 | In this document, an application is whatever is using libev. |
5488 | In this document, an application is whatever is using libev. |
5290 | |
5489 | |
… | |
… | |
5326 | watchers and events. |
5525 | watchers and events. |
5327 | |
5526 | |
5328 | =item pending |
5527 | =item pending |
5329 | |
5528 | |
5330 | A watcher is pending as soon as the corresponding event has been |
5529 | A watcher is pending as soon as the corresponding event has been |
5331 | detected. See L<WATCHER STATES> for details. |
5530 | detected. See L</WATCHER STATES> for details. |
5332 | |
5531 | |
5333 | =item real time |
5532 | =item real time |
5334 | |
5533 | |
5335 | The physical time that is observed. It is apparently strictly monotonic :) |
5534 | The physical time that is observed. It is apparently strictly monotonic :) |
5336 | |
5535 | |