… | |
… | |
43 | |
43 | |
44 | int |
44 | int |
45 | main (void) |
45 | main (void) |
46 | { |
46 | { |
47 | // use the default event loop unless you have special needs |
47 | // use the default event loop unless you have special needs |
48 | ev_loop *loop = ev_default_loop (0); |
48 | struct ev_loop *loop = ev_default_loop (0); |
49 | |
49 | |
50 | // initialise an io watcher, then start it |
50 | // initialise an io watcher, then start it |
51 | // this one will watch for stdin to become readable |
51 | // this one will watch for stdin to become readable |
52 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
52 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
53 | ev_io_start (loop, &stdin_watcher); |
53 | ev_io_start (loop, &stdin_watcher); |
… | |
… | |
460 | |
460 | |
461 | While nominally embeddable in other event loops, this doesn't work |
461 | While nominally embeddable in other event loops, this doesn't work |
462 | everywhere, so you might need to test for this. And since it is broken |
462 | everywhere, so you might need to test for this. And since it is broken |
463 | almost everywhere, you should only use it when you have a lot of sockets |
463 | almost everywhere, you should only use it when you have a lot of sockets |
464 | (for which it usually works), by embedding it into another event loop |
464 | (for which it usually works), by embedding it into another event loop |
465 | (e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>) and, did I mention it, |
465 | (e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> (but C<poll> is of course |
466 | using it only for sockets. |
466 | also broken on OS X)) and, did I mention it, using it only for sockets. |
467 | |
467 | |
468 | This backend maps C<EV_READ> into an C<EVFILT_READ> kevent with |
468 | This backend maps C<EV_READ> into an C<EVFILT_READ> kevent with |
469 | C<NOTE_EOF>, and C<EV_WRITE> into an C<EVFILT_WRITE> kevent with |
469 | C<NOTE_EOF>, and C<EV_WRITE> into an C<EVFILT_WRITE> kevent with |
470 | C<NOTE_EOF>. |
470 | C<NOTE_EOF>. |
471 | |
471 | |
… | |
… | |
633 | This function is rarely useful, but when some event callback runs for a |
633 | This function is rarely useful, but when some event callback runs for a |
634 | very long time without entering the event loop, updating libev's idea of |
634 | very long time without entering the event loop, updating libev's idea of |
635 | the current time is a good idea. |
635 | the current time is a good idea. |
636 | |
636 | |
637 | See also "The special problem of time updates" in the C<ev_timer> section. |
637 | See also "The special problem of time updates" in the C<ev_timer> section. |
|
|
638 | |
|
|
639 | =item ev_suspend (loop) |
|
|
640 | |
|
|
641 | =item ev_resume (loop) |
|
|
642 | |
|
|
643 | These two functions suspend and resume a loop, for use when the loop is |
|
|
644 | not used for a while and timeouts should not be processed. |
|
|
645 | |
|
|
646 | A typical use case would be an interactive program such as a game: When |
|
|
647 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
|
|
648 | would be best to handle timeouts as if no time had actually passed while |
|
|
649 | the program was suspended. This can be achieved by calling C<ev_suspend> |
|
|
650 | in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling |
|
|
651 | C<ev_resume> directly afterwards to resume timer processing. |
|
|
652 | |
|
|
653 | Effectively, all C<ev_timer> watchers will be delayed by the time spend |
|
|
654 | between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers |
|
|
655 | will be rescheduled (that is, they will lose any events that would have |
|
|
656 | occured while suspended). |
|
|
657 | |
|
|
658 | After calling C<ev_suspend> you B<must not> call I<any> function on the |
|
|
659 | given loop other than C<ev_resume>, and you B<must not> call C<ev_resume> |
|
|
660 | without a previous call to C<ev_suspend>. |
|
|
661 | |
|
|
662 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
|
|
663 | event loop time (see C<ev_now_update>). |
638 | |
664 | |
639 | =item ev_loop (loop, int flags) |
665 | =item ev_loop (loop, int flags) |
640 | |
666 | |
641 | Finally, this is it, the event handler. This function usually is called |
667 | Finally, this is it, the event handler. This function usually is called |
642 | after you initialised all your watchers and you want to start handling |
668 | after you initialised all your watchers and you want to start handling |
… | |
… | |
726 | |
752 | |
727 | If you have a watcher you never unregister that should not keep C<ev_loop> |
753 | If you have a watcher you never unregister that should not keep C<ev_loop> |
728 | from returning, call ev_unref() after starting, and ev_ref() before |
754 | from returning, call ev_unref() after starting, and ev_ref() before |
729 | stopping it. |
755 | stopping it. |
730 | |
756 | |
731 | As an example, libev itself uses this for its internal signal pipe: It is |
757 | As an example, libev itself uses this for its internal signal pipe: It |
732 | not visible to the libev user and should not keep C<ev_loop> from exiting |
758 | is not visible to the libev user and should not keep C<ev_loop> from |
733 | if no event watchers registered by it are active. It is also an excellent |
759 | exiting if no event watchers registered by it are active. It is also an |
734 | way to do this for generic recurring timers or from within third-party |
760 | excellent way to do this for generic recurring timers or from within |
735 | libraries. Just remember to I<unref after start> and I<ref before stop> |
761 | third-party libraries. Just remember to I<unref after start> and I<ref |
736 | (but only if the watcher wasn't active before, or was active before, |
762 | before stop> (but only if the watcher wasn't active before, or was active |
737 | respectively). |
763 | before, respectively. Note also that libev might stop watchers itself |
|
|
764 | (e.g. non-repeating timers) in which case you have to C<ev_ref> |
|
|
765 | in the callback). |
738 | |
766 | |
739 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
767 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
740 | running when nothing else is active. |
768 | running when nothing else is active. |
741 | |
769 | |
742 | ev_signal exitsig; |
770 | ev_signal exitsig; |
… | |
… | |
925 | C<ev_fork>). |
953 | C<ev_fork>). |
926 | |
954 | |
927 | =item C<EV_ASYNC> |
955 | =item C<EV_ASYNC> |
928 | |
956 | |
929 | The given async watcher has been asynchronously notified (see C<ev_async>). |
957 | The given async watcher has been asynchronously notified (see C<ev_async>). |
|
|
958 | |
|
|
959 | =item C<EV_CUSTOM> |
|
|
960 | |
|
|
961 | Not ever sent (or otherwise used) by libev itself, but can be freely used |
|
|
962 | by libev users to signal watchers (e.g. via C<ev_feed_event>). |
930 | |
963 | |
931 | =item C<EV_ERROR> |
964 | =item C<EV_ERROR> |
932 | |
965 | |
933 | An unspecified error has occurred, the watcher has been stopped. This might |
966 | An unspecified error has occurred, the watcher has been stopped. This might |
934 | happen because the watcher could not be properly started because libev |
967 | happen because the watcher could not be properly started because libev |
… | |
… | |
1317 | year, it will still time out after (roughly) one hour. "Roughly" because |
1350 | year, it will still time out after (roughly) one hour. "Roughly" because |
1318 | detecting time jumps is hard, and some inaccuracies are unavoidable (the |
1351 | detecting time jumps is hard, and some inaccuracies are unavoidable (the |
1319 | monotonic clock option helps a lot here). |
1352 | monotonic clock option helps a lot here). |
1320 | |
1353 | |
1321 | The callback is guaranteed to be invoked only I<after> its timeout has |
1354 | The callback is guaranteed to be invoked only I<after> its timeout has |
1322 | passed, but if multiple timers become ready during the same loop iteration |
1355 | passed. If multiple timers become ready during the same loop iteration |
1323 | then order of execution is undefined. |
1356 | then the ones with earlier time-out values are invoked before ones with |
|
|
1357 | later time-out values (but this is no longer true when a callback calls |
|
|
1358 | C<ev_loop> recursively). |
1324 | |
1359 | |
1325 | =head3 Be smart about timeouts |
1360 | =head3 Be smart about timeouts |
1326 | |
1361 | |
1327 | Many real-world problems involve some kind of timeout, usually for error |
1362 | Many real-world problems involve some kind of timeout, usually for error |
1328 | recovery. A typical example is an HTTP request - if the other side hangs, |
1363 | recovery. A typical example is an HTTP request - if the other side hangs, |
… | |
… | |
1596 | =head2 C<ev_periodic> - to cron or not to cron? |
1631 | =head2 C<ev_periodic> - to cron or not to cron? |
1597 | |
1632 | |
1598 | Periodic watchers are also timers of a kind, but they are very versatile |
1633 | Periodic watchers are also timers of a kind, but they are very versatile |
1599 | (and unfortunately a bit complex). |
1634 | (and unfortunately a bit complex). |
1600 | |
1635 | |
1601 | Unlike C<ev_timer>'s, they are not based on real time (or relative time) |
1636 | Unlike C<ev_timer>, periodic watchers are not based on real time (or |
1602 | but on wall clock time (absolute time). You can tell a periodic watcher |
1637 | relative time, the physical time that passes) but on wall clock time |
1603 | to trigger after some specific point in time. For example, if you tell a |
1638 | (absolute time, the thing you can read on your calender or clock). The |
1604 | periodic watcher to trigger in 10 seconds (by specifying e.g. C<ev_now () |
1639 | difference is that wall clock time can run faster or slower than real |
1605 | + 10.>, that is, an absolute time not a delay) and then reset your system |
1640 | time, and time jumps are not uncommon (e.g. when you adjust your |
1606 | clock to January of the previous year, then it will take more than year |
1641 | wrist-watch). |
1607 | to trigger the event (unlike an C<ev_timer>, which would still trigger |
|
|
1608 | roughly 10 seconds later as it uses a relative timeout). |
|
|
1609 | |
1642 | |
|
|
1643 | You can tell a periodic watcher to trigger after some specific point |
|
|
1644 | in time: for example, if you tell a periodic watcher to trigger "in 10 |
|
|
1645 | seconds" (by specifying e.g. C<ev_now () + 10.>, that is, an absolute time |
|
|
1646 | not a delay) and then reset your system clock to January of the previous |
|
|
1647 | year, then it will take a year or more to trigger the event (unlike an |
|
|
1648 | C<ev_timer>, which would still trigger roughly 10 seconds after starting |
|
|
1649 | it, as it uses a relative timeout). |
|
|
1650 | |
1610 | C<ev_periodic>s can also be used to implement vastly more complex timers, |
1651 | C<ev_periodic> watchers can also be used to implement vastly more complex |
1611 | such as triggering an event on each "midnight, local time", or other |
1652 | timers, such as triggering an event on each "midnight, local time", or |
1612 | complicated rules. |
1653 | other complicated rules. This cannot be done with C<ev_timer> watchers, as |
|
|
1654 | those cannot react to time jumps. |
1613 | |
1655 | |
1614 | As with timers, the callback is guaranteed to be invoked only when the |
1656 | As with timers, the callback is guaranteed to be invoked only when the |
1615 | time (C<at>) has passed, but if multiple periodic timers become ready |
1657 | point in time where it is supposed to trigger has passed. If multiple |
1616 | during the same loop iteration, then order of execution is undefined. |
1658 | timers become ready during the same loop iteration then the ones with |
|
|
1659 | earlier time-out values are invoked before ones with later time-out values |
|
|
1660 | (but this is no longer true when a callback calls C<ev_loop> recursively). |
1617 | |
1661 | |
1618 | =head3 Watcher-Specific Functions and Data Members |
1662 | =head3 Watcher-Specific Functions and Data Members |
1619 | |
1663 | |
1620 | =over 4 |
1664 | =over 4 |
1621 | |
1665 | |
1622 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1666 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb) |
1623 | |
1667 | |
1624 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
1668 | =item ev_periodic_set (ev_periodic *, ev_tstamp offset, ev_tstamp interval, reschedule_cb) |
1625 | |
1669 | |
1626 | Lots of arguments, lets sort it out... There are basically three modes of |
1670 | Lots of arguments, let's sort it out... There are basically three modes of |
1627 | operation, and we will explain them from simplest to most complex: |
1671 | operation, and we will explain them from simplest to most complex: |
1628 | |
1672 | |
1629 | =over 4 |
1673 | =over 4 |
1630 | |
1674 | |
1631 | =item * absolute timer (at = time, interval = reschedule_cb = 0) |
1675 | =item * absolute timer (offset = absolute time, interval = 0, reschedule_cb = 0) |
1632 | |
1676 | |
1633 | In this configuration the watcher triggers an event after the wall clock |
1677 | In this configuration the watcher triggers an event after the wall clock |
1634 | time C<at> has passed. It will not repeat and will not adjust when a time |
1678 | time C<offset> has passed. It will not repeat and will not adjust when a |
1635 | jump occurs, that is, if it is to be run at January 1st 2011 then it will |
1679 | time jump occurs, that is, if it is to be run at January 1st 2011 then it |
1636 | only run when the system clock reaches or surpasses this time. |
1680 | will be stopped and invoked when the system clock reaches or surpasses |
|
|
1681 | this point in time. |
1637 | |
1682 | |
1638 | =item * repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1683 | =item * repeating interval timer (offset = offset within interval, interval > 0, reschedule_cb = 0) |
1639 | |
1684 | |
1640 | In this mode the watcher will always be scheduled to time out at the next |
1685 | In this mode the watcher will always be scheduled to time out at the next |
1641 | C<at + N * interval> time (for some integer N, which can also be negative) |
1686 | C<offset + N * interval> time (for some integer N, which can also be |
1642 | and then repeat, regardless of any time jumps. |
1687 | negative) and then repeat, regardless of any time jumps. The C<offset> |
|
|
1688 | argument is merely an offset into the C<interval> periods. |
1643 | |
1689 | |
1644 | This can be used to create timers that do not drift with respect to the |
1690 | This can be used to create timers that do not drift with respect to the |
1645 | system clock, for example, here is a C<ev_periodic> that triggers each |
1691 | system clock, for example, here is an C<ev_periodic> that triggers each |
1646 | hour, on the hour: |
1692 | hour, on the hour (with respect to UTC): |
1647 | |
1693 | |
1648 | ev_periodic_set (&periodic, 0., 3600., 0); |
1694 | ev_periodic_set (&periodic, 0., 3600., 0); |
1649 | |
1695 | |
1650 | This doesn't mean there will always be 3600 seconds in between triggers, |
1696 | This doesn't mean there will always be 3600 seconds in between triggers, |
1651 | but only that the callback will be called when the system time shows a |
1697 | but only that the callback will be called when the system time shows a |
1652 | full hour (UTC), or more correctly, when the system time is evenly divisible |
1698 | full hour (UTC), or more correctly, when the system time is evenly divisible |
1653 | by 3600. |
1699 | by 3600. |
1654 | |
1700 | |
1655 | Another way to think about it (for the mathematically inclined) is that |
1701 | Another way to think about it (for the mathematically inclined) is that |
1656 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1702 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1657 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1703 | time where C<time = offset (mod interval)>, regardless of any time jumps. |
1658 | |
1704 | |
1659 | For numerical stability it is preferable that the C<at> value is near |
1705 | For numerical stability it is preferable that the C<offset> value is near |
1660 | C<ev_now ()> (the current time), but there is no range requirement for |
1706 | C<ev_now ()> (the current time), but there is no range requirement for |
1661 | this value, and in fact is often specified as zero. |
1707 | this value, and in fact is often specified as zero. |
1662 | |
1708 | |
1663 | Note also that there is an upper limit to how often a timer can fire (CPU |
1709 | Note also that there is an upper limit to how often a timer can fire (CPU |
1664 | speed for example), so if C<interval> is very small then timing stability |
1710 | speed for example), so if C<interval> is very small then timing stability |
1665 | will of course deteriorate. Libev itself tries to be exact to be about one |
1711 | will of course deteriorate. Libev itself tries to be exact to be about one |
1666 | millisecond (if the OS supports it and the machine is fast enough). |
1712 | millisecond (if the OS supports it and the machine is fast enough). |
1667 | |
1713 | |
1668 | =item * manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
1714 | =item * manual reschedule mode (offset ignored, interval ignored, reschedule_cb = callback) |
1669 | |
1715 | |
1670 | In this mode the values for C<interval> and C<at> are both being |
1716 | In this mode the values for C<interval> and C<offset> are both being |
1671 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1717 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1672 | reschedule callback will be called with the watcher as first, and the |
1718 | reschedule callback will be called with the watcher as first, and the |
1673 | current time as second argument. |
1719 | current time as second argument. |
1674 | |
1720 | |
1675 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1721 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, ever, |
1676 | ever, or make ANY event loop modifications whatsoever>. |
1722 | or make ANY other event loop modifications whatsoever, unless explicitly |
|
|
1723 | allowed by documentation here>. |
1677 | |
1724 | |
1678 | If you need to stop it, return C<now + 1e30> (or so, fudge fudge) and stop |
1725 | If you need to stop it, return C<now + 1e30> (or so, fudge fudge) and stop |
1679 | it afterwards (e.g. by starting an C<ev_prepare> watcher, which is the |
1726 | it afterwards (e.g. by starting an C<ev_prepare> watcher, which is the |
1680 | only event loop modification you are allowed to do). |
1727 | only event loop modification you are allowed to do). |
1681 | |
1728 | |
… | |
… | |
1711 | a different time than the last time it was called (e.g. in a crond like |
1758 | a different time than the last time it was called (e.g. in a crond like |
1712 | program when the crontabs have changed). |
1759 | program when the crontabs have changed). |
1713 | |
1760 | |
1714 | =item ev_tstamp ev_periodic_at (ev_periodic *) |
1761 | =item ev_tstamp ev_periodic_at (ev_periodic *) |
1715 | |
1762 | |
1716 | When active, returns the absolute time that the watcher is supposed to |
1763 | When active, returns the absolute time that the watcher is supposed |
1717 | trigger next. |
1764 | to trigger next. This is not the same as the C<offset> argument to |
|
|
1765 | C<ev_periodic_set>, but indeed works even in interval and manual |
|
|
1766 | rescheduling modes. |
1718 | |
1767 | |
1719 | =item ev_tstamp offset [read-write] |
1768 | =item ev_tstamp offset [read-write] |
1720 | |
1769 | |
1721 | When repeating, this contains the offset value, otherwise this is the |
1770 | When repeating, this contains the offset value, otherwise this is the |
1722 | absolute point in time (the C<at> value passed to C<ev_periodic_set>). |
1771 | absolute point in time (the C<offset> value passed to C<ev_periodic_set>, |
|
|
1772 | although libev might modify this value for better numerical stability). |
1723 | |
1773 | |
1724 | Can be modified any time, but changes only take effect when the periodic |
1774 | Can be modified any time, but changes only take effect when the periodic |
1725 | timer fires or C<ev_periodic_again> is being called. |
1775 | timer fires or C<ev_periodic_again> is being called. |
1726 | |
1776 | |
1727 | =item ev_tstamp interval [read-write] |
1777 | =item ev_tstamp interval [read-write] |
… | |
… | |
2012 | the process. The exception are C<ev_stat> watchers - those call C<stat |
2062 | the process. The exception are C<ev_stat> watchers - those call C<stat |
2013 | ()>, which is a synchronous operation. |
2063 | ()>, which is a synchronous operation. |
2014 | |
2064 | |
2015 | For local paths, this usually doesn't matter: unless the system is very |
2065 | For local paths, this usually doesn't matter: unless the system is very |
2016 | busy or the intervals between stat's are large, a stat call will be fast, |
2066 | busy or the intervals between stat's are large, a stat call will be fast, |
2017 | as the path data is suually in memory already (except when starting the |
2067 | as the path data is usually in memory already (except when starting the |
2018 | watcher). |
2068 | watcher). |
2019 | |
2069 | |
2020 | For networked file systems, calling C<stat ()> can block an indefinite |
2070 | For networked file systems, calling C<stat ()> can block an indefinite |
2021 | time due to network issues, and even under good conditions, a stat call |
2071 | time due to network issues, and even under good conditions, a stat call |
2022 | often takes multiple milliseconds. |
2072 | often takes multiple milliseconds. |
… | |
… | |
2179 | |
2229 | |
2180 | =head3 Watcher-Specific Functions and Data Members |
2230 | =head3 Watcher-Specific Functions and Data Members |
2181 | |
2231 | |
2182 | =over 4 |
2232 | =over 4 |
2183 | |
2233 | |
2184 | =item ev_idle_init (ev_signal *, callback) |
2234 | =item ev_idle_init (ev_idle *, callback) |
2185 | |
2235 | |
2186 | Initialises and configures the idle watcher - it has no parameters of any |
2236 | Initialises and configures the idle watcher - it has no parameters of any |
2187 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
2237 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
2188 | believe me. |
2238 | believe me. |
2189 | |
2239 | |
… | |
… | |
2428 | some fds have to be watched and handled very quickly (with low latency), |
2478 | some fds have to be watched and handled very quickly (with low latency), |
2429 | and even priorities and idle watchers might have too much overhead. In |
2479 | and even priorities and idle watchers might have too much overhead. In |
2430 | this case you would put all the high priority stuff in one loop and all |
2480 | this case you would put all the high priority stuff in one loop and all |
2431 | the rest in a second one, and embed the second one in the first. |
2481 | the rest in a second one, and embed the second one in the first. |
2432 | |
2482 | |
2433 | As long as the watcher is active, the callback will be invoked every time |
2483 | As long as the watcher is active, the callback will be invoked every |
2434 | there might be events pending in the embedded loop. The callback must then |
2484 | time there might be events pending in the embedded loop. The callback |
2435 | call C<ev_embed_sweep (mainloop, watcher)> to make a single sweep and invoke |
2485 | must then call C<ev_embed_sweep (mainloop, watcher)> to make a single |
2436 | their callbacks (you could also start an idle watcher to give the embedded |
2486 | sweep and invoke their callbacks (the callback doesn't need to invoke the |
2437 | loop strictly lower priority for example). You can also set the callback |
2487 | C<ev_embed_sweep> function directly, it could also start an idle watcher |
2438 | to C<0>, in which case the embed watcher will automatically execute the |
2488 | to give the embedded loop strictly lower priority for example). |
2439 | embedded loop sweep. |
|
|
2440 | |
2489 | |
2441 | As long as the watcher is started it will automatically handle events. The |
2490 | You can also set the callback to C<0>, in which case the embed watcher |
2442 | callback will be invoked whenever some events have been handled. You can |
2491 | will automatically execute the embedded loop sweep whenever necessary. |
2443 | set the callback to C<0> to avoid having to specify one if you are not |
|
|
2444 | interested in that. |
|
|
2445 | |
2492 | |
2446 | Also, there have not currently been made special provisions for forking: |
2493 | Fork detection will be handled transparently while the C<ev_embed> watcher |
2447 | when you fork, you not only have to call C<ev_loop_fork> on both loops, |
2494 | is active, i.e., the embedded loop will automatically be forked when the |
2448 | but you will also have to stop and restart any C<ev_embed> watchers |
2495 | embedding loop forks. In other cases, the user is responsible for calling |
2449 | yourself - but you can use a fork watcher to handle this automatically, |
2496 | C<ev_loop_fork> on the embedded loop. |
2450 | and future versions of libev might do just that. |
|
|
2451 | |
2497 | |
2452 | Unfortunately, not all backends are embeddable: only the ones returned by |
2498 | Unfortunately, not all backends are embeddable: only the ones returned by |
2453 | C<ev_embeddable_backends> are, which, unfortunately, does not include any |
2499 | C<ev_embeddable_backends> are, which, unfortunately, does not include any |
2454 | portable one. |
2500 | portable one. |
2455 | |
2501 | |
… | |
… | |
2686 | an C<EV_ASYNC> event on the watcher into the event loop. Unlike |
2732 | an C<EV_ASYNC> event on the watcher into the event loop. Unlike |
2687 | C<ev_feed_event>, this call is safe to do from other threads, signal or |
2733 | C<ev_feed_event>, this call is safe to do from other threads, signal or |
2688 | similar contexts (see the discussion of C<EV_ATOMIC_T> in the embedding |
2734 | similar contexts (see the discussion of C<EV_ATOMIC_T> in the embedding |
2689 | section below on what exactly this means). |
2735 | section below on what exactly this means). |
2690 | |
2736 | |
|
|
2737 | Note that, as with other watchers in libev, multiple events might get |
|
|
2738 | compressed into a single callback invocation (another way to look at this |
|
|
2739 | is that C<ev_async> watchers are level-triggered, set on C<ev_async_send>, |
|
|
2740 | reset when the event loop detects that). |
|
|
2741 | |
2691 | This call incurs the overhead of a system call only once per loop iteration, |
2742 | This call incurs the overhead of a system call only once per event loop |
2692 | so while the overhead might be noticeable, it doesn't apply to repeated |
2743 | iteration, so while the overhead might be noticeable, it doesn't apply to |
2693 | calls to C<ev_async_send>. |
2744 | repeated calls to C<ev_async_send> for the same event loop. |
2694 | |
2745 | |
2695 | =item bool = ev_async_pending (ev_async *) |
2746 | =item bool = ev_async_pending (ev_async *) |
2696 | |
2747 | |
2697 | Returns a non-zero value when C<ev_async_send> has been called on the |
2748 | Returns a non-zero value when C<ev_async_send> has been called on the |
2698 | watcher but the event has not yet been processed (or even noted) by the |
2749 | watcher but the event has not yet been processed (or even noted) by the |
… | |
… | |
2701 | C<ev_async_send> sets a flag in the watcher and wakes up the loop. When |
2752 | C<ev_async_send> sets a flag in the watcher and wakes up the loop. When |
2702 | the loop iterates next and checks for the watcher to have become active, |
2753 | the loop iterates next and checks for the watcher to have become active, |
2703 | it will reset the flag again. C<ev_async_pending> can be used to very |
2754 | it will reset the flag again. C<ev_async_pending> can be used to very |
2704 | quickly check whether invoking the loop might be a good idea. |
2755 | quickly check whether invoking the loop might be a good idea. |
2705 | |
2756 | |
2706 | Not that this does I<not> check whether the watcher itself is pending, only |
2757 | Not that this does I<not> check whether the watcher itself is pending, |
2707 | whether it has been requested to make this watcher pending. |
2758 | only whether it has been requested to make this watcher pending: there |
|
|
2759 | is a time window between the event loop checking and resetting the async |
|
|
2760 | notification, and the callback being invoked. |
2708 | |
2761 | |
2709 | =back |
2762 | =back |
2710 | |
2763 | |
2711 | |
2764 | |
2712 | =head1 OTHER FUNCTIONS |
2765 | =head1 OTHER FUNCTIONS |
… | |
… | |
2891 | |
2944 | |
2892 | myclass obj; |
2945 | myclass obj; |
2893 | ev::io iow; |
2946 | ev::io iow; |
2894 | iow.set <myclass, &myclass::io_cb> (&obj); |
2947 | iow.set <myclass, &myclass::io_cb> (&obj); |
2895 | |
2948 | |
|
|
2949 | =item w->set (object *) |
|
|
2950 | |
|
|
2951 | This is an B<experimental> feature that might go away in a future version. |
|
|
2952 | |
|
|
2953 | This is a variation of a method callback - leaving out the method to call |
|
|
2954 | will default the method to C<operator ()>, which makes it possible to use |
|
|
2955 | functor objects without having to manually specify the C<operator ()> all |
|
|
2956 | the time. Incidentally, you can then also leave out the template argument |
|
|
2957 | list. |
|
|
2958 | |
|
|
2959 | The C<operator ()> method prototype must be C<void operator ()(watcher &w, |
|
|
2960 | int revents)>. |
|
|
2961 | |
|
|
2962 | See the method-C<set> above for more details. |
|
|
2963 | |
|
|
2964 | Example: use a functor object as callback. |
|
|
2965 | |
|
|
2966 | struct myfunctor |
|
|
2967 | { |
|
|
2968 | void operator() (ev::io &w, int revents) |
|
|
2969 | { |
|
|
2970 | ... |
|
|
2971 | } |
|
|
2972 | } |
|
|
2973 | |
|
|
2974 | myfunctor f; |
|
|
2975 | |
|
|
2976 | ev::io w; |
|
|
2977 | w.set (&f); |
|
|
2978 | |
2896 | =item w->set<function> (void *data = 0) |
2979 | =item w->set<function> (void *data = 0) |
2897 | |
2980 | |
2898 | Also sets a callback, but uses a static method or plain function as |
2981 | Also sets a callback, but uses a static method or plain function as |
2899 | callback. The optional C<data> argument will be stored in the watcher's |
2982 | callback. The optional C<data> argument will be stored in the watcher's |
2900 | C<data> member and is free for you to use. |
2983 | C<data> member and is free for you to use. |
… | |
… | |
2986 | L<http://software.schmorp.de/pkg/EV>. |
3069 | L<http://software.schmorp.de/pkg/EV>. |
2987 | |
3070 | |
2988 | =item Python |
3071 | =item Python |
2989 | |
3072 | |
2990 | Python bindings can be found at L<http://code.google.com/p/pyev/>. It |
3073 | Python bindings can be found at L<http://code.google.com/p/pyev/>. It |
2991 | seems to be quite complete and well-documented. Note, however, that the |
3074 | seems to be quite complete and well-documented. |
2992 | patch they require for libev is outright dangerous as it breaks the ABI |
|
|
2993 | for everybody else, and therefore, should never be applied in an installed |
|
|
2994 | libev (if python requires an incompatible ABI then it needs to embed |
|
|
2995 | libev). |
|
|
2996 | |
3075 | |
2997 | =item Ruby |
3076 | =item Ruby |
2998 | |
3077 | |
2999 | Tony Arcieri has written a ruby extension that offers access to a subset |
3078 | Tony Arcieri has written a ruby extension that offers access to a subset |
3000 | of the libev API and adds file handle abstractions, asynchronous DNS and |
3079 | of the libev API and adds file handle abstractions, asynchronous DNS and |
3001 | more on top of it. It can be found via gem servers. Its homepage is at |
3080 | more on top of it. It can be found via gem servers. Its homepage is at |
3002 | L<http://rev.rubyforge.org/>. |
3081 | L<http://rev.rubyforge.org/>. |
3003 | |
3082 | |
3004 | Roger Pack reports that using the link order C<-lws2_32 -lmsvcrt-ruby-190> |
3083 | Roger Pack reports that using the link order C<-lws2_32 -lmsvcrt-ruby-190> |
3005 | makes rev work even on mingw. |
3084 | makes rev work even on mingw. |
|
|
3085 | |
|
|
3086 | =item Haskell |
|
|
3087 | |
|
|
3088 | A haskell binding to libev is available at |
|
|
3089 | L<http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hlibev>. |
3006 | |
3090 | |
3007 | =item D |
3091 | =item D |
3008 | |
3092 | |
3009 | Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to |
3093 | Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to |
3010 | be found at L<http://proj.llucax.com.ar/wiki/evd>. |
3094 | be found at L<http://proj.llucax.com.ar/wiki/evd>. |
… | |
… | |
3203 | function is hiding in (often F<-lrt>). See also C<EV_USE_CLOCK_SYSCALL>. |
3287 | function is hiding in (often F<-lrt>). See also C<EV_USE_CLOCK_SYSCALL>. |
3204 | |
3288 | |
3205 | =item EV_USE_REALTIME |
3289 | =item EV_USE_REALTIME |
3206 | |
3290 | |
3207 | If defined to be C<1>, libev will try to detect the availability of the |
3291 | If defined to be C<1>, libev will try to detect the availability of the |
3208 | real-time clock option at compile time (and assume its availability at |
3292 | real-time clock option at compile time (and assume its availability |
3209 | runtime if successful). Otherwise no use of the real-time clock option will |
3293 | at runtime if successful). Otherwise no use of the real-time clock |
3210 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
3294 | option will be attempted. This effectively replaces C<gettimeofday> |
3211 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See the |
3295 | by C<clock_get (CLOCK_REALTIME, ...)> and will not normally affect |
3212 | note about libraries in the description of C<EV_USE_MONOTONIC>, though. |
3296 | correctness. See the note about libraries in the description of |
|
|
3297 | C<EV_USE_MONOTONIC>, though. Defaults to the opposite value of |
|
|
3298 | C<EV_USE_CLOCK_SYSCALL>. |
3213 | |
3299 | |
3214 | =item EV_USE_CLOCK_SYSCALL |
3300 | =item EV_USE_CLOCK_SYSCALL |
3215 | |
3301 | |
3216 | If defined to be C<1>, libev will try to use a direct syscall instead |
3302 | If defined to be C<1>, libev will try to use a direct syscall instead |
3217 | of calling the system-provided C<clock_gettime> function. This option |
3303 | of calling the system-provided C<clock_gettime> function. This option |