… | |
… | |
53 | The newest version of this document is also available as a html-formatted |
53 | The newest version of this document is also available as a html-formatted |
54 | web page you might find easier to navigate when reading it for the first |
54 | web page you might find easier to navigate when reading it for the first |
55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
56 | |
56 | |
57 | Libev is an event loop: you register interest in certain events (such as a |
57 | Libev is an event loop: you register interest in certain events (such as a |
58 | file descriptor being readable or a timeout occuring), and it will manage |
58 | file descriptor being readable or a timeout occurring), and it will manage |
59 | these event sources and provide your program with events. |
59 | these event sources and provide your program with events. |
60 | |
60 | |
61 | To do this, it must take more or less complete control over your process |
61 | To do this, it must take more or less complete control over your process |
62 | (or thread) by executing the I<event loop> handler, and will then |
62 | (or thread) by executing the I<event loop> handler, and will then |
63 | communicate events via a callback mechanism. |
63 | communicate events via a callback mechanism. |
… | |
… | |
98 | Libev represents time as a single floating point number, representing the |
98 | Libev represents time as a single floating point number, representing the |
99 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
99 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
100 | the beginning of 1970, details are complicated, don't ask). This type is |
100 | the beginning of 1970, details are complicated, don't ask). This type is |
101 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
101 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
102 | to the C<double> type in C, and when you need to do any calculations on |
102 | to the C<double> type in C, and when you need to do any calculations on |
103 | it, you should treat it as such. |
103 | it, you should treat it as some floatingpoint value. Unlike the name |
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|
104 | component C<stamp> might indicate, it is also used for time differences |
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105 | throughout libev. |
104 | |
106 | |
105 | =head1 GLOBAL FUNCTIONS |
107 | =head1 GLOBAL FUNCTIONS |
106 | |
108 | |
107 | These functions can be called anytime, even before initialising the |
109 | These functions can be called anytime, even before initialising the |
108 | library in any way. |
110 | library in any way. |
… | |
… | |
113 | |
115 | |
114 | Returns the current time as libev would use it. Please note that the |
116 | Returns the current time as libev would use it. Please note that the |
115 | C<ev_now> function is usually faster and also often returns the timestamp |
117 | C<ev_now> function is usually faster and also often returns the timestamp |
116 | you actually want to know. |
118 | you actually want to know. |
117 | |
119 | |
|
|
120 | =item ev_sleep (ev_tstamp interval) |
|
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121 | |
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122 | Sleep for the given interval: The current thread will be blocked until |
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123 | either it is interrupted or the given time interval has passed. Basically |
|
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124 | this is a subsecond-resolution C<sleep ()>. |
|
|
125 | |
118 | =item int ev_version_major () |
126 | =item int ev_version_major () |
119 | |
127 | |
120 | =item int ev_version_minor () |
128 | =item int ev_version_minor () |
121 | |
129 | |
122 | You can find out the major and minor version numbers of the library |
130 | You can find out the major and minor ABI version numbers of the library |
123 | you linked against by calling the functions C<ev_version_major> and |
131 | you linked against by calling the functions C<ev_version_major> and |
124 | C<ev_version_minor>. If you want, you can compare against the global |
132 | C<ev_version_minor>. If you want, you can compare against the global |
125 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
133 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
126 | version of the library your program was compiled against. |
134 | version of the library your program was compiled against. |
127 | |
135 | |
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|
136 | These version numbers refer to the ABI version of the library, not the |
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137 | release version. |
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138 | |
128 | Usually, it's a good idea to terminate if the major versions mismatch, |
139 | Usually, it's a good idea to terminate if the major versions mismatch, |
129 | as this indicates an incompatible change. Minor versions are usually |
140 | as this indicates an incompatible change. Minor versions are usually |
130 | compatible to older versions, so a larger minor version alone is usually |
141 | compatible to older versions, so a larger minor version alone is usually |
131 | not a problem. |
142 | not a problem. |
132 | |
143 | |
133 | Example: Make sure we haven't accidentally been linked against the wrong |
144 | Example: Make sure we haven't accidentally been linked against the wrong |
134 | version. |
145 | version. |
… | |
… | |
308 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
319 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
309 | |
320 | |
310 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
321 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
311 | |
322 | |
312 | For few fds, this backend is a bit little slower than poll and select, |
323 | For few fds, this backend is a bit little slower than poll and select, |
313 | but it scales phenomenally better. While poll and select usually scale like |
324 | but it scales phenomenally better. While poll and select usually scale |
314 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
325 | like O(total_fds) where n is the total number of fds (or the highest fd), |
315 | either O(1) or O(active_fds). |
326 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
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327 | of shortcomings, such as silently dropping events in some hard-to-detect |
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328 | cases and rewiring a syscall per fd change, no fork support and bad |
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329 | support for dup: |
316 | |
330 | |
317 | While stopping and starting an I/O watcher in the same iteration will |
331 | While stopping, setting and starting an I/O watcher in the same iteration |
318 | result in some caching, there is still a syscall per such incident |
332 | will result in some caching, there is still a syscall per such incident |
319 | (because the fd could point to a different file description now), so its |
333 | (because the fd could point to a different file description now), so its |
320 | best to avoid that. Also, dup()ed file descriptors might not work very |
334 | best to avoid that. Also, C<dup ()>'ed file descriptors might not work |
321 | well if you register events for both fds. |
335 | very well if you register events for both fds. |
322 | |
336 | |
323 | Please note that epoll sometimes generates spurious notifications, so you |
337 | Please note that epoll sometimes generates spurious notifications, so you |
324 | need to use non-blocking I/O or other means to avoid blocking when no data |
338 | need to use non-blocking I/O or other means to avoid blocking when no data |
325 | (or space) is available. |
339 | (or space) is available. |
326 | |
340 | |
327 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
341 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
328 | |
342 | |
329 | Kqueue deserves special mention, as at the time of this writing, it |
343 | Kqueue deserves special mention, as at the time of this writing, it |
330 | was broken on all BSDs except NetBSD (usually it doesn't work with |
344 | was broken on I<all> BSDs (usually it doesn't work with anything but |
331 | anything but sockets and pipes, except on Darwin, where of course its |
345 | sockets and pipes, except on Darwin, where of course it's completely |
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346 | useless. On NetBSD, it seems to work for all the FD types I tested, so it |
332 | completely useless). For this reason its not being "autodetected" |
347 | is used by default there). For this reason it's not being "autodetected" |
333 | unless you explicitly specify it explicitly in the flags (i.e. using |
348 | unless you explicitly specify it explicitly in the flags (i.e. using |
334 | C<EVBACKEND_KQUEUE>). |
349 | C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough) |
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|
350 | system like NetBSD. |
335 | |
351 | |
336 | It scales in the same way as the epoll backend, but the interface to the |
352 | It scales in the same way as the epoll backend, but the interface to the |
337 | kernel is more efficient (which says nothing about its actual speed, of |
353 | kernel is more efficient (which says nothing about its actual speed, |
338 | course). While starting and stopping an I/O watcher does not cause an |
354 | of course). While stopping, setting and starting an I/O watcher does |
339 | extra syscall as with epoll, it still adds up to four event changes per |
355 | never cause an extra syscall as with epoll, it still adds up to two event |
340 | incident, so its best to avoid that. |
356 | changes per incident, support for C<fork ()> is very bad and it drops fds |
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|
357 | silently in similarly hard-to-detetc cases. |
341 | |
358 | |
342 | =item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8) |
359 | =item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8) |
343 | |
360 | |
344 | This is not implemented yet (and might never be). |
361 | This is not implemented yet (and might never be). |
345 | |
362 | |
346 | =item C<EVBACKEND_PORT> (value 32, Solaris 10) |
363 | =item C<EVBACKEND_PORT> (value 32, Solaris 10) |
347 | |
364 | |
348 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
365 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
349 | it's really slow, but it still scales very well (O(active_fds)). |
366 | it's really slow, but it still scales very well (O(active_fds)). |
350 | |
367 | |
351 | Please note that solaris ports can result in a lot of spurious |
368 | Please note that solaris event ports can deliver a lot of spurious |
352 | notifications, so you need to use non-blocking I/O or other means to avoid |
369 | notifications, so you need to use non-blocking I/O or other means to avoid |
353 | blocking when no data (or space) is available. |
370 | blocking when no data (or space) is available. |
354 | |
371 | |
355 | =item C<EVBACKEND_ALL> |
372 | =item C<EVBACKEND_ALL> |
356 | |
373 | |
… | |
… | |
399 | Destroys the default loop again (frees all memory and kernel state |
416 | Destroys the default loop again (frees all memory and kernel state |
400 | etc.). None of the active event watchers will be stopped in the normal |
417 | etc.). None of the active event watchers will be stopped in the normal |
401 | sense, so e.g. C<ev_is_active> might still return true. It is your |
418 | sense, so e.g. C<ev_is_active> might still return true. It is your |
402 | responsibility to either stop all watchers cleanly yoursef I<before> |
419 | responsibility to either stop all watchers cleanly yoursef I<before> |
403 | calling this function, or cope with the fact afterwards (which is usually |
420 | calling this function, or cope with the fact afterwards (which is usually |
404 | the easiest thing, youc na just ignore the watchers and/or C<free ()> them |
421 | the easiest thing, you can just ignore the watchers and/or C<free ()> them |
405 | for example). |
422 | for example). |
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|
423 | |
|
|
424 | Note that certain global state, such as signal state, will not be freed by |
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425 | this function, and related watchers (such as signal and child watchers) |
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426 | would need to be stopped manually. |
|
|
427 | |
|
|
428 | In general it is not advisable to call this function except in the |
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429 | rare occasion where you really need to free e.g. the signal handling |
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430 | pipe fds. If you need dynamically allocated loops it is better to use |
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|
431 | C<ev_loop_new> and C<ev_loop_destroy>). |
406 | |
432 | |
407 | =item ev_loop_destroy (loop) |
433 | =item ev_loop_destroy (loop) |
408 | |
434 | |
409 | Like C<ev_default_destroy>, but destroys an event loop created by an |
435 | Like C<ev_default_destroy>, but destroys an event loop created by an |
410 | earlier call to C<ev_loop_new>. |
436 | earlier call to C<ev_loop_new>. |
… | |
… | |
455 | |
481 | |
456 | Returns the current "event loop time", which is the time the event loop |
482 | Returns the current "event loop time", which is the time the event loop |
457 | received events and started processing them. This timestamp does not |
483 | received events and started processing them. This timestamp does not |
458 | change as long as callbacks are being processed, and this is also the base |
484 | change as long as callbacks are being processed, and this is also the base |
459 | time used for relative timers. You can treat it as the timestamp of the |
485 | time used for relative timers. You can treat it as the timestamp of the |
460 | event occuring (or more correctly, libev finding out about it). |
486 | event occurring (or more correctly, libev finding out about it). |
461 | |
487 | |
462 | =item ev_loop (loop, int flags) |
488 | =item ev_loop (loop, int flags) |
463 | |
489 | |
464 | Finally, this is it, the event handler. This function usually is called |
490 | Finally, this is it, the event handler. This function usually is called |
465 | after you initialised all your watchers and you want to start handling |
491 | after you initialised all your watchers and you want to start handling |
… | |
… | |
486 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
512 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
487 | usually a better approach for this kind of thing. |
513 | usually a better approach for this kind of thing. |
488 | |
514 | |
489 | Here are the gory details of what C<ev_loop> does: |
515 | Here are the gory details of what C<ev_loop> does: |
490 | |
516 | |
|
|
517 | - Before the first iteration, call any pending watchers. |
491 | * If there are no active watchers (reference count is zero), return. |
518 | * If there are no active watchers (reference count is zero), return. |
492 | - Queue prepare watchers and then call all outstanding watchers. |
519 | - Queue all prepare watchers and then call all outstanding watchers. |
493 | - If we have been forked, recreate the kernel state. |
520 | - If we have been forked, recreate the kernel state. |
494 | - Update the kernel state with all outstanding changes. |
521 | - Update the kernel state with all outstanding changes. |
495 | - Update the "event loop time". |
522 | - Update the "event loop time". |
496 | - Calculate for how long to block. |
523 | - Calculate for how long to block. |
497 | - Block the process, waiting for any events. |
524 | - Block the process, waiting for any events. |
… | |
… | |
548 | Example: For some weird reason, unregister the above signal handler again. |
575 | Example: For some weird reason, unregister the above signal handler again. |
549 | |
576 | |
550 | ev_ref (loop); |
577 | ev_ref (loop); |
551 | ev_signal_stop (loop, &exitsig); |
578 | ev_signal_stop (loop, &exitsig); |
552 | |
579 | |
|
|
580 | =item ev_set_io_collect_interval (loop, ev_tstamp interval) |
|
|
581 | |
|
|
582 | =item ev_set_timeout_collect_interval (loop, ev_tstamp interval) |
|
|
583 | |
|
|
584 | These advanced functions influence the time that libev will spend waiting |
|
|
585 | for events. Both are by default C<0>, meaning that libev will try to |
|
|
586 | invoke timer/periodic callbacks and I/O callbacks with minimum latency. |
|
|
587 | |
|
|
588 | Setting these to a higher value (the C<interval> I<must> be >= C<0>) |
|
|
589 | allows libev to delay invocation of I/O and timer/periodic callbacks to |
|
|
590 | increase efficiency of loop iterations. |
|
|
591 | |
|
|
592 | The background is that sometimes your program runs just fast enough to |
|
|
593 | handle one (or very few) event(s) per loop iteration. While this makes |
|
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594 | the program responsive, it also wastes a lot of CPU time to poll for new |
|
|
595 | events, especially with backends like C<select ()> which have a high |
|
|
596 | overhead for the actual polling but can deliver many events at once. |
|
|
597 | |
|
|
598 | By setting a higher I<io collect interval> you allow libev to spend more |
|
|
599 | time collecting I/O events, so you can handle more events per iteration, |
|
|
600 | at the cost of increasing latency. Timeouts (both C<ev_periodic> and |
|
|
601 | C<ev_timer>) will be not affected. |
|
|
602 | |
|
|
603 | Likewise, by setting a higher I<timeout collect interval> you allow libev |
|
|
604 | to spend more time collecting timeouts, at the expense of increased |
|
|
605 | latency (the watcher callback will be called later). C<ev_io> watchers |
|
|
606 | will not be affected. |
|
|
607 | |
|
|
608 | Many (busy) programs can usually benefit by setting the io collect |
|
|
609 | interval to a value near C<0.1> or so, which is often enough for |
|
|
610 | interactive servers (of course not for games), likewise for timeouts. It |
|
|
611 | usually doesn't make much sense to set it to a lower value than C<0.01>, |
|
|
612 | as this approsaches the timing granularity of most systems. |
|
|
613 | |
553 | =back |
614 | =back |
554 | |
615 | |
555 | |
616 | |
556 | =head1 ANATOMY OF A WATCHER |
617 | =head1 ANATOMY OF A WATCHER |
557 | |
618 | |
… | |
… | |
776 | always C<0>, which is supposed to not be too high and not be too low :). |
837 | always C<0>, which is supposed to not be too high and not be too low :). |
777 | |
838 | |
778 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
839 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
779 | fine, as long as you do not mind that the priority value you query might |
840 | fine, as long as you do not mind that the priority value you query might |
780 | or might not have been adjusted to be within valid range. |
841 | or might not have been adjusted to be within valid range. |
|
|
842 | |
|
|
843 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
|
|
844 | |
|
|
845 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
|
|
846 | C<loop> nor C<revents> need to be valid as long as the watcher callback |
|
|
847 | can deal with that fact. |
|
|
848 | |
|
|
849 | =item int ev_clear_pending (loop, ev_TYPE *watcher) |
|
|
850 | |
|
|
851 | If the watcher is pending, this function returns clears its pending status |
|
|
852 | and returns its C<revents> bitset (as if its callback was invoked). If the |
|
|
853 | watcher isn't pending it does nothing and returns C<0>. |
781 | |
854 | |
782 | =back |
855 | =back |
783 | |
856 | |
784 | |
857 | |
785 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
858 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
895 | play around with an Xlib connection), then you have to seperately re-test |
968 | play around with an Xlib connection), then you have to seperately re-test |
896 | whether a file descriptor is really ready with a known-to-be good interface |
969 | whether a file descriptor is really ready with a known-to-be good interface |
897 | such as poll (fortunately in our Xlib example, Xlib already does this on |
970 | such as poll (fortunately in our Xlib example, Xlib already does this on |
898 | its own, so its quite safe to use). |
971 | its own, so its quite safe to use). |
899 | |
972 | |
|
|
973 | =head3 The special problem of disappearing file descriptors |
|
|
974 | |
|
|
975 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
|
|
976 | descriptor (either by calling C<close> explicitly or by any other means, |
|
|
977 | such as C<dup>). The reason is that you register interest in some file |
|
|
978 | descriptor, but when it goes away, the operating system will silently drop |
|
|
979 | this interest. If another file descriptor with the same number then is |
|
|
980 | registered with libev, there is no efficient way to see that this is, in |
|
|
981 | fact, a different file descriptor. |
|
|
982 | |
|
|
983 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
984 | the following policy: Each time C<ev_io_set> is being called, libev |
|
|
985 | will assume that this is potentially a new file descriptor, otherwise |
|
|
986 | it is assumed that the file descriptor stays the same. That means that |
|
|
987 | you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the |
|
|
988 | descriptor even if the file descriptor number itself did not change. |
|
|
989 | |
|
|
990 | This is how one would do it normally anyway, the important point is that |
|
|
991 | the libev application should not optimise around libev but should leave |
|
|
992 | optimisations to libev. |
|
|
993 | |
|
|
994 | =head3 The special problem of dup'ed file descriptors |
|
|
995 | |
|
|
996 | Some backends (e.g. epoll), cannot register events for file descriptors, |
|
|
997 | but only events for the underlying file descriptions. That menas when you |
|
|
998 | have C<dup ()>'ed file descriptors and register events for them, only one |
|
|
999 | file descriptor might actually receive events. |
|
|
1000 | |
|
|
1001 | There is no workaorund possible except not registering events |
|
|
1002 | for potentially C<dup ()>'ed file descriptors or to resort to |
|
|
1003 | C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>. |
|
|
1004 | |
|
|
1005 | =head3 The special problem of fork |
|
|
1006 | |
|
|
1007 | Some backends (epoll, kqueue) do not support C<fork ()> at all or exhibit |
|
|
1008 | useless behaviour. Libev fully supports fork, but needs to be told about |
|
|
1009 | it in the child. |
|
|
1010 | |
|
|
1011 | To support fork in your programs, you either have to call |
|
|
1012 | C<ev_default_fork ()> or C<ev_loop_fork ()> after a fork in the child, |
|
|
1013 | enable C<EVFLAG_FORKCHECK>, or resort to C<EVBACKEND_SELECT> or |
|
|
1014 | C<EVBACKEND_POLL>. |
|
|
1015 | |
|
|
1016 | |
|
|
1017 | =head3 Watcher-Specific Functions |
|
|
1018 | |
900 | =over 4 |
1019 | =over 4 |
901 | |
1020 | |
902 | =item ev_io_init (ev_io *, callback, int fd, int events) |
1021 | =item ev_io_init (ev_io *, callback, int fd, int events) |
903 | |
1022 | |
904 | =item ev_io_set (ev_io *, int fd, int events) |
1023 | =item ev_io_set (ev_io *, int fd, int events) |
… | |
… | |
956 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
1075 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
957 | |
1076 | |
958 | The callback is guarenteed to be invoked only when its timeout has passed, |
1077 | The callback is guarenteed to be invoked only when its timeout has passed, |
959 | but if multiple timers become ready during the same loop iteration then |
1078 | but if multiple timers become ready during the same loop iteration then |
960 | order of execution is undefined. |
1079 | order of execution is undefined. |
|
|
1080 | |
|
|
1081 | =head3 Watcher-Specific Functions and Data Members |
961 | |
1082 | |
962 | =over 4 |
1083 | =over 4 |
963 | |
1084 | |
964 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
1085 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
965 | |
1086 | |
… | |
… | |
1061 | but on wallclock time (absolute time). You can tell a periodic watcher |
1182 | but on wallclock time (absolute time). You can tell a periodic watcher |
1062 | to trigger "at" some specific point in time. For example, if you tell a |
1183 | to trigger "at" some specific point in time. For example, if you tell a |
1063 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1184 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1064 | + 10.>) and then reset your system clock to the last year, then it will |
1185 | + 10.>) and then reset your system clock to the last year, then it will |
1065 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1186 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1066 | roughly 10 seconds later and of course not if you reset your system time |
1187 | roughly 10 seconds later). |
1067 | again). |
|
|
1068 | |
1188 | |
1069 | They can also be used to implement vastly more complex timers, such as |
1189 | They can also be used to implement vastly more complex timers, such as |
1070 | triggering an event on eahc midnight, local time. |
1190 | triggering an event on each midnight, local time or other, complicated, |
|
|
1191 | rules. |
1071 | |
1192 | |
1072 | As with timers, the callback is guarenteed to be invoked only when the |
1193 | As with timers, the callback is guarenteed to be invoked only when the |
1073 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1194 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1074 | during the same loop iteration then order of execution is undefined. |
1195 | during the same loop iteration then order of execution is undefined. |
1075 | |
1196 | |
|
|
1197 | =head3 Watcher-Specific Functions and Data Members |
|
|
1198 | |
1076 | =over 4 |
1199 | =over 4 |
1077 | |
1200 | |
1078 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1201 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1079 | |
1202 | |
1080 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
1203 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
… | |
… | |
1082 | Lots of arguments, lets sort it out... There are basically three modes of |
1205 | Lots of arguments, lets sort it out... There are basically three modes of |
1083 | operation, and we will explain them from simplest to complex: |
1206 | operation, and we will explain them from simplest to complex: |
1084 | |
1207 | |
1085 | =over 4 |
1208 | =over 4 |
1086 | |
1209 | |
1087 | =item * absolute timer (interval = reschedule_cb = 0) |
1210 | =item * absolute timer (at = time, interval = reschedule_cb = 0) |
1088 | |
1211 | |
1089 | In this configuration the watcher triggers an event at the wallclock time |
1212 | In this configuration the watcher triggers an event at the wallclock time |
1090 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1213 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1091 | that is, if it is to be run at January 1st 2011 then it will run when the |
1214 | that is, if it is to be run at January 1st 2011 then it will run when the |
1092 | system time reaches or surpasses this time. |
1215 | system time reaches or surpasses this time. |
1093 | |
1216 | |
1094 | =item * non-repeating interval timer (interval > 0, reschedule_cb = 0) |
1217 | =item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1095 | |
1218 | |
1096 | In this mode the watcher will always be scheduled to time out at the next |
1219 | In this mode the watcher will always be scheduled to time out at the next |
1097 | C<at + N * interval> time (for some integer N) and then repeat, regardless |
1220 | C<at + N * interval> time (for some integer N, which can also be negative) |
1098 | of any time jumps. |
1221 | and then repeat, regardless of any time jumps. |
1099 | |
1222 | |
1100 | This can be used to create timers that do not drift with respect to system |
1223 | This can be used to create timers that do not drift with respect to system |
1101 | time: |
1224 | time: |
1102 | |
1225 | |
1103 | ev_periodic_set (&periodic, 0., 3600., 0); |
1226 | ev_periodic_set (&periodic, 0., 3600., 0); |
… | |
… | |
1109 | |
1232 | |
1110 | Another way to think about it (for the mathematically inclined) is that |
1233 | Another way to think about it (for the mathematically inclined) is that |
1111 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1234 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1112 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1235 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1113 | |
1236 | |
|
|
1237 | For numerical stability it is preferable that the C<at> value is near |
|
|
1238 | C<ev_now ()> (the current time), but there is no range requirement for |
|
|
1239 | this value. |
|
|
1240 | |
1114 | =item * manual reschedule mode (reschedule_cb = callback) |
1241 | =item * manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
1115 | |
1242 | |
1116 | In this mode the values for C<interval> and C<at> are both being |
1243 | In this mode the values for C<interval> and C<at> are both being |
1117 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1244 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1118 | reschedule callback will be called with the watcher as first, and the |
1245 | reschedule callback will be called with the watcher as first, and the |
1119 | current time as second argument. |
1246 | current time as second argument. |
1120 | |
1247 | |
1121 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1248 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1122 | ever, or make any event loop modifications>. If you need to stop it, |
1249 | ever, or make any event loop modifications>. If you need to stop it, |
1123 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1250 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1124 | starting a prepare watcher). |
1251 | starting an C<ev_prepare> watcher, which is legal). |
1125 | |
1252 | |
1126 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1253 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1127 | ev_tstamp now)>, e.g.: |
1254 | ev_tstamp now)>, e.g.: |
1128 | |
1255 | |
1129 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
1256 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
1152 | Simply stops and restarts the periodic watcher again. This is only useful |
1279 | Simply stops and restarts the periodic watcher again. This is only useful |
1153 | when you changed some parameters or the reschedule callback would return |
1280 | when you changed some parameters or the reschedule callback would return |
1154 | a different time than the last time it was called (e.g. in a crond like |
1281 | a different time than the last time it was called (e.g. in a crond like |
1155 | program when the crontabs have changed). |
1282 | program when the crontabs have changed). |
1156 | |
1283 | |
|
|
1284 | =item ev_tstamp offset [read-write] |
|
|
1285 | |
|
|
1286 | When repeating, this contains the offset value, otherwise this is the |
|
|
1287 | absolute point in time (the C<at> value passed to C<ev_periodic_set>). |
|
|
1288 | |
|
|
1289 | Can be modified any time, but changes only take effect when the periodic |
|
|
1290 | timer fires or C<ev_periodic_again> is being called. |
|
|
1291 | |
1157 | =item ev_tstamp interval [read-write] |
1292 | =item ev_tstamp interval [read-write] |
1158 | |
1293 | |
1159 | The current interval value. Can be modified any time, but changes only |
1294 | The current interval value. Can be modified any time, but changes only |
1160 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1295 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1161 | called. |
1296 | called. |
… | |
… | |
1163 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
1298 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
1164 | |
1299 | |
1165 | The current reschedule callback, or C<0>, if this functionality is |
1300 | The current reschedule callback, or C<0>, if this functionality is |
1166 | switched off. Can be changed any time, but changes only take effect when |
1301 | switched off. Can be changed any time, but changes only take effect when |
1167 | the periodic timer fires or C<ev_periodic_again> is being called. |
1302 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
|
1303 | |
|
|
1304 | =item ev_tstamp at [read-only] |
|
|
1305 | |
|
|
1306 | When active, contains the absolute time that the watcher is supposed to |
|
|
1307 | trigger next. |
1168 | |
1308 | |
1169 | =back |
1309 | =back |
1170 | |
1310 | |
1171 | Example: Call a callback every hour, or, more precisely, whenever the |
1311 | Example: Call a callback every hour, or, more precisely, whenever the |
1172 | system clock is divisible by 3600. The callback invocation times have |
1312 | system clock is divisible by 3600. The callback invocation times have |
… | |
… | |
1214 | with the kernel (thus it coexists with your own signal handlers as long |
1354 | with the kernel (thus it coexists with your own signal handlers as long |
1215 | as you don't register any with libev). Similarly, when the last signal |
1355 | as you don't register any with libev). Similarly, when the last signal |
1216 | watcher for a signal is stopped libev will reset the signal handler to |
1356 | watcher for a signal is stopped libev will reset the signal handler to |
1217 | SIG_DFL (regardless of what it was set to before). |
1357 | SIG_DFL (regardless of what it was set to before). |
1218 | |
1358 | |
|
|
1359 | =head3 Watcher-Specific Functions and Data Members |
|
|
1360 | |
1219 | =over 4 |
1361 | =over 4 |
1220 | |
1362 | |
1221 | =item ev_signal_init (ev_signal *, callback, int signum) |
1363 | =item ev_signal_init (ev_signal *, callback, int signum) |
1222 | |
1364 | |
1223 | =item ev_signal_set (ev_signal *, int signum) |
1365 | =item ev_signal_set (ev_signal *, int signum) |
… | |
… | |
1234 | |
1376 | |
1235 | =head2 C<ev_child> - watch out for process status changes |
1377 | =head2 C<ev_child> - watch out for process status changes |
1236 | |
1378 | |
1237 | Child watchers trigger when your process receives a SIGCHLD in response to |
1379 | Child watchers trigger when your process receives a SIGCHLD in response to |
1238 | some child status changes (most typically when a child of yours dies). |
1380 | some child status changes (most typically when a child of yours dies). |
|
|
1381 | |
|
|
1382 | =head3 Watcher-Specific Functions and Data Members |
1239 | |
1383 | |
1240 | =over 4 |
1384 | =over 4 |
1241 | |
1385 | |
1242 | =item ev_child_init (ev_child *, callback, int pid) |
1386 | =item ev_child_init (ev_child *, callback, int pid) |
1243 | |
1387 | |
… | |
… | |
1311 | reader). Inotify will be used to give hints only and should not change the |
1455 | reader). Inotify will be used to give hints only and should not change the |
1312 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1456 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1313 | to fall back to regular polling again even with inotify, but changes are |
1457 | to fall back to regular polling again even with inotify, but changes are |
1314 | usually detected immediately, and if the file exists there will be no |
1458 | usually detected immediately, and if the file exists there will be no |
1315 | polling. |
1459 | polling. |
|
|
1460 | |
|
|
1461 | =head3 Watcher-Specific Functions and Data Members |
1316 | |
1462 | |
1317 | =over 4 |
1463 | =over 4 |
1318 | |
1464 | |
1319 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1465 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1320 | |
1466 | |
… | |
… | |
1403 | Apart from keeping your process non-blocking (which is a useful |
1549 | Apart from keeping your process non-blocking (which is a useful |
1404 | effect on its own sometimes), idle watchers are a good place to do |
1550 | effect on its own sometimes), idle watchers are a good place to do |
1405 | "pseudo-background processing", or delay processing stuff to after the |
1551 | "pseudo-background processing", or delay processing stuff to after the |
1406 | event loop has handled all outstanding events. |
1552 | event loop has handled all outstanding events. |
1407 | |
1553 | |
|
|
1554 | =head3 Watcher-Specific Functions and Data Members |
|
|
1555 | |
1408 | =over 4 |
1556 | =over 4 |
1409 | |
1557 | |
1410 | =item ev_idle_init (ev_signal *, callback) |
1558 | =item ev_idle_init (ev_signal *, callback) |
1411 | |
1559 | |
1412 | Initialises and configures the idle watcher - it has no parameters of any |
1560 | Initialises and configures the idle watcher - it has no parameters of any |
… | |
… | |
1469 | with priority higher than or equal to the event loop and one coroutine |
1617 | with priority higher than or equal to the event loop and one coroutine |
1470 | of lower priority, but only once, using idle watchers to keep the event |
1618 | of lower priority, but only once, using idle watchers to keep the event |
1471 | loop from blocking if lower-priority coroutines are active, thus mapping |
1619 | loop from blocking if lower-priority coroutines are active, thus mapping |
1472 | low-priority coroutines to idle/background tasks). |
1620 | low-priority coroutines to idle/background tasks). |
1473 | |
1621 | |
|
|
1622 | It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>) |
|
|
1623 | priority, to ensure that they are being run before any other watchers |
|
|
1624 | after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers, |
|
|
1625 | too) should not activate ("feed") events into libev. While libev fully |
|
|
1626 | supports this, they will be called before other C<ev_check> watchers did |
|
|
1627 | their job. As C<ev_check> watchers are often used to embed other event |
|
|
1628 | loops those other event loops might be in an unusable state until their |
|
|
1629 | C<ev_check> watcher ran (always remind yourself to coexist peacefully with |
|
|
1630 | others). |
|
|
1631 | |
|
|
1632 | =head3 Watcher-Specific Functions and Data Members |
|
|
1633 | |
1474 | =over 4 |
1634 | =over 4 |
1475 | |
1635 | |
1476 | =item ev_prepare_init (ev_prepare *, callback) |
1636 | =item ev_prepare_init (ev_prepare *, callback) |
1477 | |
1637 | |
1478 | =item ev_check_init (ev_check *, callback) |
1638 | =item ev_check_init (ev_check *, callback) |
… | |
… | |
1481 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1641 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1482 | macros, but using them is utterly, utterly and completely pointless. |
1642 | macros, but using them is utterly, utterly and completely pointless. |
1483 | |
1643 | |
1484 | =back |
1644 | =back |
1485 | |
1645 | |
1486 | Example: To include a library such as adns, you would add IO watchers |
1646 | There are a number of principal ways to embed other event loops or modules |
1487 | and a timeout watcher in a prepare handler, as required by libadns, and |
1647 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1648 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
|
|
1649 | use for an actually working example. Another Perl module named C<EV::Glib> |
|
|
1650 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
|
|
1651 | into the Glib event loop). |
|
|
1652 | |
|
|
1653 | Method 1: Add IO watchers and a timeout watcher in a prepare handler, |
1488 | in a check watcher, destroy them and call into libadns. What follows is |
1654 | and in a check watcher, destroy them and call into libadns. What follows |
1489 | pseudo-code only of course: |
1655 | is pseudo-code only of course. This requires you to either use a low |
|
|
1656 | priority for the check watcher or use C<ev_clear_pending> explicitly, as |
|
|
1657 | the callbacks for the IO/timeout watchers might not have been called yet. |
1490 | |
1658 | |
1491 | static ev_io iow [nfd]; |
1659 | static ev_io iow [nfd]; |
1492 | static ev_timer tw; |
1660 | static ev_timer tw; |
1493 | |
1661 | |
1494 | static void |
1662 | static void |
1495 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1663 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1496 | { |
1664 | { |
1497 | // set the relevant poll flags |
|
|
1498 | // could also call adns_processreadable etc. here |
|
|
1499 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1500 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1501 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1502 | } |
1665 | } |
1503 | |
1666 | |
1504 | // create io watchers for each fd and a timer before blocking |
1667 | // create io watchers for each fd and a timer before blocking |
1505 | static void |
1668 | static void |
1506 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1669 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
… | |
… | |
1512 | |
1675 | |
1513 | /* the callback is illegal, but won't be called as we stop during check */ |
1676 | /* the callback is illegal, but won't be called as we stop during check */ |
1514 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1677 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1515 | ev_timer_start (loop, &tw); |
1678 | ev_timer_start (loop, &tw); |
1516 | |
1679 | |
1517 | // create on ev_io per pollfd |
1680 | // create one ev_io per pollfd |
1518 | for (int i = 0; i < nfd; ++i) |
1681 | for (int i = 0; i < nfd; ++i) |
1519 | { |
1682 | { |
1520 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1683 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1521 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1684 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1522 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1685 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1523 | |
1686 | |
1524 | fds [i].revents = 0; |
1687 | fds [i].revents = 0; |
1525 | iow [i].data = fds + i; |
|
|
1526 | ev_io_start (loop, iow + i); |
1688 | ev_io_start (loop, iow + i); |
1527 | } |
1689 | } |
1528 | } |
1690 | } |
1529 | |
1691 | |
1530 | // stop all watchers after blocking |
1692 | // stop all watchers after blocking |
… | |
… | |
1532 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1694 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1533 | { |
1695 | { |
1534 | ev_timer_stop (loop, &tw); |
1696 | ev_timer_stop (loop, &tw); |
1535 | |
1697 | |
1536 | for (int i = 0; i < nfd; ++i) |
1698 | for (int i = 0; i < nfd; ++i) |
|
|
1699 | { |
|
|
1700 | // set the relevant poll flags |
|
|
1701 | // could also call adns_processreadable etc. here |
|
|
1702 | struct pollfd *fd = fds + i; |
|
|
1703 | int revents = ev_clear_pending (iow + i); |
|
|
1704 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1705 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1706 | |
|
|
1707 | // now stop the watcher |
1537 | ev_io_stop (loop, iow + i); |
1708 | ev_io_stop (loop, iow + i); |
|
|
1709 | } |
1538 | |
1710 | |
1539 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1711 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1712 | } |
|
|
1713 | |
|
|
1714 | Method 2: This would be just like method 1, but you run C<adns_afterpoll> |
|
|
1715 | in the prepare watcher and would dispose of the check watcher. |
|
|
1716 | |
|
|
1717 | Method 3: If the module to be embedded supports explicit event |
|
|
1718 | notification (adns does), you can also make use of the actual watcher |
|
|
1719 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1720 | |
|
|
1721 | static void |
|
|
1722 | timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1723 | { |
|
|
1724 | adns_state ads = (adns_state)w->data; |
|
|
1725 | update_now (EV_A); |
|
|
1726 | |
|
|
1727 | adns_processtimeouts (ads, &tv_now); |
|
|
1728 | } |
|
|
1729 | |
|
|
1730 | static void |
|
|
1731 | io_cb (EV_P_ ev_io *w, int revents) |
|
|
1732 | { |
|
|
1733 | adns_state ads = (adns_state)w->data; |
|
|
1734 | update_now (EV_A); |
|
|
1735 | |
|
|
1736 | if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1737 | if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1738 | } |
|
|
1739 | |
|
|
1740 | // do not ever call adns_afterpoll |
|
|
1741 | |
|
|
1742 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1743 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1744 | their poll function. The drawback with this solution is that the main |
|
|
1745 | loop is now no longer controllable by EV. The C<Glib::EV> module does |
|
|
1746 | this. |
|
|
1747 | |
|
|
1748 | static gint |
|
|
1749 | event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1750 | { |
|
|
1751 | int got_events = 0; |
|
|
1752 | |
|
|
1753 | for (n = 0; n < nfds; ++n) |
|
|
1754 | // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1755 | |
|
|
1756 | if (timeout >= 0) |
|
|
1757 | // create/start timer |
|
|
1758 | |
|
|
1759 | // poll |
|
|
1760 | ev_loop (EV_A_ 0); |
|
|
1761 | |
|
|
1762 | // stop timer again |
|
|
1763 | if (timeout >= 0) |
|
|
1764 | ev_timer_stop (EV_A_ &to); |
|
|
1765 | |
|
|
1766 | // stop io watchers again - their callbacks should have set |
|
|
1767 | for (n = 0; n < nfds; ++n) |
|
|
1768 | ev_io_stop (EV_A_ iow [n]); |
|
|
1769 | |
|
|
1770 | return got_events; |
1540 | } |
1771 | } |
1541 | |
1772 | |
1542 | |
1773 | |
1543 | =head2 C<ev_embed> - when one backend isn't enough... |
1774 | =head2 C<ev_embed> - when one backend isn't enough... |
1544 | |
1775 | |
1545 | This is a rather advanced watcher type that lets you embed one event loop |
1776 | This is a rather advanced watcher type that lets you embed one event loop |
1546 | into another (currently only C<ev_io> events are supported in the embedded |
1777 | into another (currently only C<ev_io> events are supported in the embedded |
1547 | loop, other types of watchers might be handled in a delayed or incorrect |
1778 | loop, other types of watchers might be handled in a delayed or incorrect |
1548 | fashion and must not be used). |
1779 | fashion and must not be used). (See portability notes, below). |
1549 | |
1780 | |
1550 | There are primarily two reasons you would want that: work around bugs and |
1781 | There are primarily two reasons you would want that: work around bugs and |
1551 | prioritise I/O. |
1782 | prioritise I/O. |
1552 | |
1783 | |
1553 | As an example for a bug workaround, the kqueue backend might only support |
1784 | As an example for a bug workaround, the kqueue backend might only support |
… | |
… | |
1608 | ev_embed_start (loop_hi, &embed); |
1839 | ev_embed_start (loop_hi, &embed); |
1609 | } |
1840 | } |
1610 | else |
1841 | else |
1611 | loop_lo = loop_hi; |
1842 | loop_lo = loop_hi; |
1612 | |
1843 | |
|
|
1844 | =head2 Portability notes |
|
|
1845 | |
|
|
1846 | Kqueue is nominally embeddable, but this is broken on all BSDs that I |
|
|
1847 | tried, in various ways. Usually the embedded event loop will simply never |
|
|
1848 | receive events, sometimes it will only trigger a few times, sometimes in a |
|
|
1849 | loop. Epoll is also nominally embeddable, but many Linux kernel versions |
|
|
1850 | will always eport the epoll fd as ready, even when no events are pending. |
|
|
1851 | |
|
|
1852 | While libev allows embedding these backends (they are contained in |
|
|
1853 | C<ev_embeddable_backends ()>), take extreme care that it will actually |
|
|
1854 | work. |
|
|
1855 | |
|
|
1856 | When in doubt, create a dynamic event loop forced to use sockets (this |
|
|
1857 | usually works) and possibly another thread and a pipe or so to report to |
|
|
1858 | your main event loop. |
|
|
1859 | |
|
|
1860 | =head3 Watcher-Specific Functions and Data Members |
|
|
1861 | |
1613 | =over 4 |
1862 | =over 4 |
1614 | |
1863 | |
1615 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1864 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1616 | |
1865 | |
1617 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
1866 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
… | |
… | |
1626 | |
1875 | |
1627 | Make a single, non-blocking sweep over the embedded loop. This works |
1876 | Make a single, non-blocking sweep over the embedded loop. This works |
1628 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1877 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1629 | apropriate way for embedded loops. |
1878 | apropriate way for embedded loops. |
1630 | |
1879 | |
1631 | =item struct ev_loop *loop [read-only] |
1880 | =item struct ev_loop *other [read-only] |
1632 | |
1881 | |
1633 | The embedded event loop. |
1882 | The embedded event loop. |
1634 | |
1883 | |
1635 | =back |
1884 | =back |
1636 | |
1885 | |
… | |
… | |
1643 | event loop blocks next and before C<ev_check> watchers are being called, |
1892 | event loop blocks next and before C<ev_check> watchers are being called, |
1644 | and only in the child after the fork. If whoever good citizen calling |
1893 | and only in the child after the fork. If whoever good citizen calling |
1645 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1894 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1646 | handlers will be invoked, too, of course. |
1895 | handlers will be invoked, too, of course. |
1647 | |
1896 | |
|
|
1897 | =head3 Watcher-Specific Functions and Data Members |
|
|
1898 | |
1648 | =over 4 |
1899 | =over 4 |
1649 | |
1900 | |
1650 | =item ev_fork_init (ev_signal *, callback) |
1901 | =item ev_fork_init (ev_signal *, callback) |
1651 | |
1902 | |
1652 | Initialises and configures the fork watcher - it has no parameters of any |
1903 | Initialises and configures the fork watcher - it has no parameters of any |
… | |
… | |
1832 | |
2083 | |
1833 | myclass obj; |
2084 | myclass obj; |
1834 | ev::io iow; |
2085 | ev::io iow; |
1835 | iow.set <myclass, &myclass::io_cb> (&obj); |
2086 | iow.set <myclass, &myclass::io_cb> (&obj); |
1836 | |
2087 | |
1837 | =item w->set (void (*function)(watcher &w, int), void *data = 0) |
2088 | =item w->set<function> (void *data = 0) |
1838 | |
2089 | |
1839 | Also sets a callback, but uses a static method or plain function as |
2090 | Also sets a callback, but uses a static method or plain function as |
1840 | callback. The optional C<data> argument will be stored in the watcher's |
2091 | callback. The optional C<data> argument will be stored in the watcher's |
1841 | C<data> member and is free for you to use. |
2092 | C<data> member and is free for you to use. |
1842 | |
2093 | |
|
|
2094 | The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>. |
|
|
2095 | |
1843 | See the method-C<set> above for more details. |
2096 | See the method-C<set> above for more details. |
|
|
2097 | |
|
|
2098 | Example: |
|
|
2099 | |
|
|
2100 | static void io_cb (ev::io &w, int revents) { } |
|
|
2101 | iow.set <io_cb> (); |
1844 | |
2102 | |
1845 | =item w->set (struct ev_loop *) |
2103 | =item w->set (struct ev_loop *) |
1846 | |
2104 | |
1847 | Associates a different C<struct ev_loop> with this watcher. You can only |
2105 | Associates a different C<struct ev_loop> with this watcher. You can only |
1848 | do this when the watcher is inactive (and not pending either). |
2106 | do this when the watcher is inactive (and not pending either). |
… | |
… | |
1861 | |
2119 | |
1862 | =item w->stop () |
2120 | =item w->stop () |
1863 | |
2121 | |
1864 | Stops the watcher if it is active. Again, no C<loop> argument. |
2122 | Stops the watcher if it is active. Again, no C<loop> argument. |
1865 | |
2123 | |
1866 | =item w->again () C<ev::timer>, C<ev::periodic> only |
2124 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
1867 | |
2125 | |
1868 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
2126 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
1869 | C<ev_TYPE_again> function. |
2127 | C<ev_TYPE_again> function. |
1870 | |
2128 | |
1871 | =item w->sweep () C<ev::embed> only |
2129 | =item w->sweep () (C<ev::embed> only) |
1872 | |
2130 | |
1873 | Invokes C<ev_embed_sweep>. |
2131 | Invokes C<ev_embed_sweep>. |
1874 | |
2132 | |
1875 | =item w->update () C<ev::stat> only |
2133 | =item w->update () (C<ev::stat> only) |
1876 | |
2134 | |
1877 | Invokes C<ev_stat_stat>. |
2135 | Invokes C<ev_stat_stat>. |
1878 | |
2136 | |
1879 | =back |
2137 | =back |
1880 | |
2138 | |
… | |
… | |
1900 | } |
2158 | } |
1901 | |
2159 | |
1902 | |
2160 | |
1903 | =head1 MACRO MAGIC |
2161 | =head1 MACRO MAGIC |
1904 | |
2162 | |
1905 | Libev can be compiled with a variety of options, the most fundemantal is |
2163 | Libev can be compiled with a variety of options, the most fundamantal |
1906 | C<EV_MULTIPLICITY>. This option determines whether (most) functions and |
2164 | of which is C<EV_MULTIPLICITY>. This option determines whether (most) |
1907 | callbacks have an initial C<struct ev_loop *> argument. |
2165 | functions and callbacks have an initial C<struct ev_loop *> argument. |
1908 | |
2166 | |
1909 | To make it easier to write programs that cope with either variant, the |
2167 | To make it easier to write programs that cope with either variant, the |
1910 | following macros are defined: |
2168 | following macros are defined: |
1911 | |
2169 | |
1912 | =over 4 |
2170 | =over 4 |
… | |
… | |
1966 | Libev can (and often is) directly embedded into host |
2224 | Libev can (and often is) directly embedded into host |
1967 | applications. Examples of applications that embed it include the Deliantra |
2225 | applications. Examples of applications that embed it include the Deliantra |
1968 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
2226 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1969 | and rxvt-unicode. |
2227 | and rxvt-unicode. |
1970 | |
2228 | |
1971 | The goal is to enable you to just copy the neecssary files into your |
2229 | The goal is to enable you to just copy the necessary files into your |
1972 | source directory without having to change even a single line in them, so |
2230 | source directory without having to change even a single line in them, so |
1973 | you can easily upgrade by simply copying (or having a checked-out copy of |
2231 | you can easily upgrade by simply copying (or having a checked-out copy of |
1974 | libev somewhere in your source tree). |
2232 | libev somewhere in your source tree). |
1975 | |
2233 | |
1976 | =head2 FILESETS |
2234 | =head2 FILESETS |
… | |
… | |
2066 | |
2324 | |
2067 | If defined to be C<1>, libev will try to detect the availability of the |
2325 | If defined to be C<1>, libev will try to detect the availability of the |
2068 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2326 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2069 | of the monotonic clock option will be attempted. If you enable this, you |
2327 | of the monotonic clock option will be attempted. If you enable this, you |
2070 | usually have to link against librt or something similar. Enabling it when |
2328 | usually have to link against librt or something similar. Enabling it when |
2071 | the functionality isn't available is safe, though, althoguh you have |
2329 | the functionality isn't available is safe, though, although you have |
2072 | to make sure you link against any libraries where the C<clock_gettime> |
2330 | to make sure you link against any libraries where the C<clock_gettime> |
2073 | function is hiding in (often F<-lrt>). |
2331 | function is hiding in (often F<-lrt>). |
2074 | |
2332 | |
2075 | =item EV_USE_REALTIME |
2333 | =item EV_USE_REALTIME |
2076 | |
2334 | |
2077 | If defined to be C<1>, libev will try to detect the availability of the |
2335 | If defined to be C<1>, libev will try to detect the availability of the |
2078 | realtime clock option at compiletime (and assume its availability at |
2336 | realtime clock option at compiletime (and assume its availability at |
2079 | runtime if successful). Otherwise no use of the realtime clock option will |
2337 | runtime if successful). Otherwise no use of the realtime clock option will |
2080 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
2338 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
2081 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See tzhe note about libraries |
2339 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See the |
2082 | in the description of C<EV_USE_MONOTONIC>, though. |
2340 | note about libraries in the description of C<EV_USE_MONOTONIC>, though. |
|
|
2341 | |
|
|
2342 | =item EV_USE_NANOSLEEP |
|
|
2343 | |
|
|
2344 | If defined to be C<1>, libev will assume that C<nanosleep ()> is available |
|
|
2345 | and will use it for delays. Otherwise it will use C<select ()>. |
2083 | |
2346 | |
2084 | =item EV_USE_SELECT |
2347 | =item EV_USE_SELECT |
2085 | |
2348 | |
2086 | If undefined or defined to be C<1>, libev will compile in support for the |
2349 | If undefined or defined to be C<1>, libev will compile in support for the |
2087 | C<select>(2) backend. No attempt at autodetection will be done: if no |
2350 | C<select>(2) backend. No attempt at autodetection will be done: if no |
… | |
… | |
2266 | |
2529 | |
2267 | =item ev_set_cb (ev, cb) |
2530 | =item ev_set_cb (ev, cb) |
2268 | |
2531 | |
2269 | Can be used to change the callback member declaration in each watcher, |
2532 | Can be used to change the callback member declaration in each watcher, |
2270 | and the way callbacks are invoked and set. Must expand to a struct member |
2533 | and the way callbacks are invoked and set. Must expand to a struct member |
2271 | definition and a statement, respectively. See the F<ev.v> header file for |
2534 | definition and a statement, respectively. See the F<ev.h> header file for |
2272 | their default definitions. One possible use for overriding these is to |
2535 | their default definitions. One possible use for overriding these is to |
2273 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
2536 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
2274 | method calls instead of plain function calls in C++. |
2537 | method calls instead of plain function calls in C++. |
|
|
2538 | |
|
|
2539 | =head2 EXPORTED API SYMBOLS |
|
|
2540 | |
|
|
2541 | If you need to re-export the API (e.g. via a dll) and you need a list of |
|
|
2542 | exported symbols, you can use the provided F<Symbol.*> files which list |
|
|
2543 | all public symbols, one per line: |
|
|
2544 | |
|
|
2545 | Symbols.ev for libev proper |
|
|
2546 | Symbols.event for the libevent emulation |
|
|
2547 | |
|
|
2548 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2549 | multiple versions of libev linked together (which is obviously bad in |
|
|
2550 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2551 | |
|
|
2552 | A sed command like this will create wrapper C<#define>'s that you need to |
|
|
2553 | include before including F<ev.h>: |
|
|
2554 | |
|
|
2555 | <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2556 | |
|
|
2557 | This would create a file F<wrap.h> which essentially looks like this: |
|
|
2558 | |
|
|
2559 | #define ev_backend myprefix_ev_backend |
|
|
2560 | #define ev_check_start myprefix_ev_check_start |
|
|
2561 | #define ev_check_stop myprefix_ev_check_stop |
|
|
2562 | ... |
2275 | |
2563 | |
2276 | =head2 EXAMPLES |
2564 | =head2 EXAMPLES |
2277 | |
2565 | |
2278 | For a real-world example of a program the includes libev |
2566 | For a real-world example of a program the includes libev |
2279 | verbatim, you can have a look at the EV perl module |
2567 | verbatim, you can have a look at the EV perl module |