… | |
… | |
48 | return 0; |
48 | return 0; |
49 | } |
49 | } |
50 | |
50 | |
51 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
52 | |
52 | |
|
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53 | The newest version of this document is also available as a html-formatted |
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54 | web page you might find easier to navigate when reading it for the first |
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55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
|
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56 | |
53 | Libev is an event loop: you register interest in certain events (such as a |
57 | Libev is an event loop: you register interest in certain events (such as a |
54 | file descriptor being readable or a timeout occuring), and it will manage |
58 | file descriptor being readable or a timeout occurring), and it will manage |
55 | these event sources and provide your program with events. |
59 | these event sources and provide your program with events. |
56 | |
60 | |
57 | 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 |
58 | (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 |
59 | communicate events via a callback mechanism. |
63 | communicate events via a callback mechanism. |
… | |
… | |
94 | Libev represents time as a single floating point number, representing the |
98 | Libev represents time as a single floating point number, representing the |
95 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
99 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
96 | 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 |
97 | 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 |
98 | 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 |
99 | it, you should treat it as such. |
103 | it, you should treat it as some floatingpoint value. Unlike the name |
|
|
104 | component C<stamp> might indicate, it is also used for time differences |
|
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105 | throughout libev. |
100 | |
106 | |
101 | =head1 GLOBAL FUNCTIONS |
107 | =head1 GLOBAL FUNCTIONS |
102 | |
108 | |
103 | These functions can be called anytime, even before initialising the |
109 | These functions can be called anytime, even before initialising the |
104 | library in any way. |
110 | library in any way. |
… | |
… | |
109 | |
115 | |
110 | 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 |
111 | 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 |
112 | you actually want to know. |
118 | you actually want to know. |
113 | |
119 | |
|
|
120 | =item ev_sleep (ev_tstamp interval) |
|
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121 | |
|
|
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 | |
114 | =item int ev_version_major () |
126 | =item int ev_version_major () |
115 | |
127 | |
116 | =item int ev_version_minor () |
128 | =item int ev_version_minor () |
117 | |
129 | |
118 | 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 |
119 | 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 |
120 | 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 |
121 | 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 |
122 | version of the library your program was compiled against. |
134 | version of the library your program was compiled against. |
123 | |
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 | |
124 | 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, |
125 | as this indicates an incompatible change. Minor versions are usually |
140 | as this indicates an incompatible change. Minor versions are usually |
126 | 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 |
127 | not a problem. |
142 | not a problem. |
128 | |
143 | |
129 | 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 |
130 | version. |
145 | version. |
… | |
… | |
274 | a fork, you can also make libev check for a fork in each iteration by |
289 | a fork, you can also make libev check for a fork in each iteration by |
275 | enabling this flag. |
290 | enabling this flag. |
276 | |
291 | |
277 | This works by calling C<getpid ()> on every iteration of the loop, |
292 | This works by calling C<getpid ()> on every iteration of the loop, |
278 | and thus this might slow down your event loop if you do a lot of loop |
293 | and thus this might slow down your event loop if you do a lot of loop |
279 | iterations and little real work, but is usually not noticable (on my |
294 | iterations and little real work, but is usually not noticeable (on my |
280 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
295 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
281 | without a syscall and thus I<very> fast, but my Linux system also has |
296 | without a syscall and thus I<very> fast, but my Linux system also has |
282 | C<pthread_atfork> which is even faster). |
297 | C<pthread_atfork> which is even faster). |
283 | |
298 | |
284 | The big advantage of this flag is that you can forget about fork (and |
299 | The big advantage of this flag is that you can forget about fork (and |
… | |
… | |
304 | 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). |
305 | |
320 | |
306 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
321 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
307 | |
322 | |
308 | 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, |
309 | but it scales phenomenally better. While poll and select usually scale like |
324 | but it scales phenomenally better. While poll and select usually scale |
310 | 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), |
311 | 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: |
312 | |
330 | |
313 | 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 |
314 | 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 |
315 | (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 |
316 | 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 |
317 | well if you register events for both fds. |
335 | very well if you register events for both fds. |
318 | |
336 | |
319 | Please note that epoll sometimes generates spurious notifications, so you |
337 | Please note that epoll sometimes generates spurious notifications, so you |
320 | 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 |
321 | (or space) is available. |
339 | (or space) is available. |
322 | |
340 | |
323 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
341 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
324 | |
342 | |
325 | 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 |
326 | was broken on all BSDs except NetBSD (usually it doesn't work with |
344 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
327 | anything but sockets and pipes, except on Darwin, where of course its |
345 | with anything but sockets and pipes, except on Darwin, where of course |
328 | completely useless). For this reason its not being "autodetected" |
346 | it's completely useless). For this reason it's not being "autodetected" |
329 | unless you explicitly specify it explicitly in the flags (i.e. using |
347 | unless you explicitly specify it explicitly in the flags (i.e. using |
330 | C<EVBACKEND_KQUEUE>). |
348 | C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough) |
|
|
349 | system like NetBSD. |
|
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350 | |
|
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351 | You still can embed kqueue into a normal poll or select backend and use it |
|
|
352 | only for sockets (after having made sure that sockets work with kqueue on |
|
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353 | the target platform). See C<ev_embed> watchers for more info. |
331 | |
354 | |
332 | It scales in the same way as the epoll backend, but the interface to the |
355 | It scales in the same way as the epoll backend, but the interface to the |
333 | kernel is more efficient (which says nothing about its actual speed, of |
356 | kernel is more efficient (which says nothing about its actual speed, of |
334 | course). While starting and stopping an I/O watcher does not cause an |
357 | course). While stopping, setting and starting an I/O watcher does never |
335 | extra syscall as with epoll, it still adds up to four event changes per |
358 | cause an extra syscall as with C<EVBACKEND_EPOLL>, it still adds up to |
336 | incident, so its best to avoid that. |
359 | two event changes per incident, support for C<fork ()> is very bad and it |
|
|
360 | drops fds silently in similarly hard-to-detect cases. |
337 | |
361 | |
338 | =item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8) |
362 | =item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8) |
339 | |
363 | |
340 | This is not implemented yet (and might never be). |
364 | This is not implemented yet (and might never be). |
341 | |
365 | |
342 | =item C<EVBACKEND_PORT> (value 32, Solaris 10) |
366 | =item C<EVBACKEND_PORT> (value 32, Solaris 10) |
343 | |
367 | |
344 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
368 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
345 | it's really slow, but it still scales very well (O(active_fds)). |
369 | it's really slow, but it still scales very well (O(active_fds)). |
346 | |
370 | |
347 | Please note that solaris ports can result in a lot of spurious |
371 | Please note that solaris event ports can deliver a lot of spurious |
348 | notifications, so you need to use non-blocking I/O or other means to avoid |
372 | notifications, so you need to use non-blocking I/O or other means to avoid |
349 | blocking when no data (or space) is available. |
373 | blocking when no data (or space) is available. |
350 | |
374 | |
351 | =item C<EVBACKEND_ALL> |
375 | =item C<EVBACKEND_ALL> |
352 | |
376 | |
… | |
… | |
395 | Destroys the default loop again (frees all memory and kernel state |
419 | Destroys the default loop again (frees all memory and kernel state |
396 | etc.). None of the active event watchers will be stopped in the normal |
420 | etc.). None of the active event watchers will be stopped in the normal |
397 | sense, so e.g. C<ev_is_active> might still return true. It is your |
421 | sense, so e.g. C<ev_is_active> might still return true. It is your |
398 | responsibility to either stop all watchers cleanly yoursef I<before> |
422 | responsibility to either stop all watchers cleanly yoursef I<before> |
399 | calling this function, or cope with the fact afterwards (which is usually |
423 | calling this function, or cope with the fact afterwards (which is usually |
400 | the easiest thing, youc na just ignore the watchers and/or C<free ()> them |
424 | the easiest thing, you can just ignore the watchers and/or C<free ()> them |
401 | for example). |
425 | for example). |
|
|
426 | |
|
|
427 | Note that certain global state, such as signal state, will not be freed by |
|
|
428 | this function, and related watchers (such as signal and child watchers) |
|
|
429 | would need to be stopped manually. |
|
|
430 | |
|
|
431 | In general it is not advisable to call this function except in the |
|
|
432 | rare occasion where you really need to free e.g. the signal handling |
|
|
433 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
434 | C<ev_loop_new> and C<ev_loop_destroy>). |
402 | |
435 | |
403 | =item ev_loop_destroy (loop) |
436 | =item ev_loop_destroy (loop) |
404 | |
437 | |
405 | Like C<ev_default_destroy>, but destroys an event loop created by an |
438 | Like C<ev_default_destroy>, but destroys an event loop created by an |
406 | earlier call to C<ev_loop_new>. |
439 | earlier call to C<ev_loop_new>. |
… | |
… | |
430 | |
463 | |
431 | Like C<ev_default_fork>, but acts on an event loop created by |
464 | Like C<ev_default_fork>, but acts on an event loop created by |
432 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
465 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
433 | after fork, and how you do this is entirely your own problem. |
466 | after fork, and how you do this is entirely your own problem. |
434 | |
467 | |
|
|
468 | =item unsigned int ev_loop_count (loop) |
|
|
469 | |
|
|
470 | Returns the count of loop iterations for the loop, which is identical to |
|
|
471 | the number of times libev did poll for new events. It starts at C<0> and |
|
|
472 | happily wraps around with enough iterations. |
|
|
473 | |
|
|
474 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
475 | "ticks" the number of loop iterations), as it roughly corresponds with |
|
|
476 | C<ev_prepare> and C<ev_check> calls. |
|
|
477 | |
435 | =item unsigned int ev_backend (loop) |
478 | =item unsigned int ev_backend (loop) |
436 | |
479 | |
437 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
480 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
438 | use. |
481 | use. |
439 | |
482 | |
… | |
… | |
441 | |
484 | |
442 | Returns the current "event loop time", which is the time the event loop |
485 | Returns the current "event loop time", which is the time the event loop |
443 | received events and started processing them. This timestamp does not |
486 | received events and started processing them. This timestamp does not |
444 | change as long as callbacks are being processed, and this is also the base |
487 | change as long as callbacks are being processed, and this is also the base |
445 | time used for relative timers. You can treat it as the timestamp of the |
488 | time used for relative timers. You can treat it as the timestamp of the |
446 | event occuring (or more correctly, libev finding out about it). |
489 | event occurring (or more correctly, libev finding out about it). |
447 | |
490 | |
448 | =item ev_loop (loop, int flags) |
491 | =item ev_loop (loop, int flags) |
449 | |
492 | |
450 | Finally, this is it, the event handler. This function usually is called |
493 | Finally, this is it, the event handler. This function usually is called |
451 | after you initialised all your watchers and you want to start handling |
494 | after you initialised all your watchers and you want to start handling |
… | |
… | |
472 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
515 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
473 | usually a better approach for this kind of thing. |
516 | usually a better approach for this kind of thing. |
474 | |
517 | |
475 | Here are the gory details of what C<ev_loop> does: |
518 | Here are the gory details of what C<ev_loop> does: |
476 | |
519 | |
|
|
520 | - Before the first iteration, call any pending watchers. |
477 | * If there are no active watchers (reference count is zero), return. |
521 | * If there are no active watchers (reference count is zero), return. |
478 | - Queue prepare watchers and then call all outstanding watchers. |
522 | - Queue all prepare watchers and then call all outstanding watchers. |
479 | - If we have been forked, recreate the kernel state. |
523 | - If we have been forked, recreate the kernel state. |
480 | - Update the kernel state with all outstanding changes. |
524 | - Update the kernel state with all outstanding changes. |
481 | - Update the "event loop time". |
525 | - Update the "event loop time". |
482 | - Calculate for how long to block. |
526 | - Calculate for how long to block. |
483 | - Block the process, waiting for any events. |
527 | - Block the process, waiting for any events. |
… | |
… | |
534 | Example: For some weird reason, unregister the above signal handler again. |
578 | Example: For some weird reason, unregister the above signal handler again. |
535 | |
579 | |
536 | ev_ref (loop); |
580 | ev_ref (loop); |
537 | ev_signal_stop (loop, &exitsig); |
581 | ev_signal_stop (loop, &exitsig); |
538 | |
582 | |
|
|
583 | =item ev_set_io_collect_interval (loop, ev_tstamp interval) |
|
|
584 | |
|
|
585 | =item ev_set_timeout_collect_interval (loop, ev_tstamp interval) |
|
|
586 | |
|
|
587 | These advanced functions influence the time that libev will spend waiting |
|
|
588 | for events. Both are by default C<0>, meaning that libev will try to |
|
|
589 | invoke timer/periodic callbacks and I/O callbacks with minimum latency. |
|
|
590 | |
|
|
591 | Setting these to a higher value (the C<interval> I<must> be >= C<0>) |
|
|
592 | allows libev to delay invocation of I/O and timer/periodic callbacks to |
|
|
593 | increase efficiency of loop iterations. |
|
|
594 | |
|
|
595 | The background is that sometimes your program runs just fast enough to |
|
|
596 | handle one (or very few) event(s) per loop iteration. While this makes |
|
|
597 | the program responsive, it also wastes a lot of CPU time to poll for new |
|
|
598 | events, especially with backends like C<select ()> which have a high |
|
|
599 | overhead for the actual polling but can deliver many events at once. |
|
|
600 | |
|
|
601 | By setting a higher I<io collect interval> you allow libev to spend more |
|
|
602 | time collecting I/O events, so you can handle more events per iteration, |
|
|
603 | at the cost of increasing latency. Timeouts (both C<ev_periodic> and |
|
|
604 | C<ev_timer>) will be not affected. Setting this to a non-null value will |
|
|
605 | introduce an additional C<ev_sleep ()> call into most loop iterations. |
|
|
606 | |
|
|
607 | Likewise, by setting a higher I<timeout collect interval> you allow libev |
|
|
608 | to spend more time collecting timeouts, at the expense of increased |
|
|
609 | latency (the watcher callback will be called later). C<ev_io> watchers |
|
|
610 | will not be affected. Setting this to a non-null value will not introduce |
|
|
611 | any overhead in libev. |
|
|
612 | |
|
|
613 | Many (busy) programs can usually benefit by setting the io collect |
|
|
614 | interval to a value near C<0.1> or so, which is often enough for |
|
|
615 | interactive servers (of course not for games), likewise for timeouts. It |
|
|
616 | usually doesn't make much sense to set it to a lower value than C<0.01>, |
|
|
617 | as this approsaches the timing granularity of most systems. |
|
|
618 | |
539 | =back |
619 | =back |
540 | |
620 | |
541 | |
621 | |
542 | =head1 ANATOMY OF A WATCHER |
622 | =head1 ANATOMY OF A WATCHER |
543 | |
623 | |
… | |
… | |
722 | =item bool ev_is_pending (ev_TYPE *watcher) |
802 | =item bool ev_is_pending (ev_TYPE *watcher) |
723 | |
803 | |
724 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
804 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
725 | events but its callback has not yet been invoked). As long as a watcher |
805 | events but its callback has not yet been invoked). As long as a watcher |
726 | is pending (but not active) you must not call an init function on it (but |
806 | is pending (but not active) you must not call an init function on it (but |
727 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
807 | C<ev_TYPE_set> is safe), you must not change its priority, and you must |
728 | libev (e.g. you cnanot C<free ()> it). |
808 | make sure the watcher is available to libev (e.g. you cannot C<free ()> |
|
|
809 | it). |
729 | |
810 | |
730 | =item callback ev_cb (ev_TYPE *watcher) |
811 | =item callback ev_cb (ev_TYPE *watcher) |
731 | |
812 | |
732 | Returns the callback currently set on the watcher. |
813 | Returns the callback currently set on the watcher. |
733 | |
814 | |
734 | =item ev_cb_set (ev_TYPE *watcher, callback) |
815 | =item ev_cb_set (ev_TYPE *watcher, callback) |
735 | |
816 | |
736 | Change the callback. You can change the callback at virtually any time |
817 | Change the callback. You can change the callback at virtually any time |
737 | (modulo threads). |
818 | (modulo threads). |
|
|
819 | |
|
|
820 | =item ev_set_priority (ev_TYPE *watcher, priority) |
|
|
821 | |
|
|
822 | =item int ev_priority (ev_TYPE *watcher) |
|
|
823 | |
|
|
824 | Set and query the priority of the watcher. The priority is a small |
|
|
825 | integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> |
|
|
826 | (default: C<-2>). Pending watchers with higher priority will be invoked |
|
|
827 | before watchers with lower priority, but priority will not keep watchers |
|
|
828 | from being executed (except for C<ev_idle> watchers). |
|
|
829 | |
|
|
830 | This means that priorities are I<only> used for ordering callback |
|
|
831 | invocation after new events have been received. This is useful, for |
|
|
832 | example, to reduce latency after idling, or more often, to bind two |
|
|
833 | watchers on the same event and make sure one is called first. |
|
|
834 | |
|
|
835 | If you need to suppress invocation when higher priority events are pending |
|
|
836 | you need to look at C<ev_idle> watchers, which provide this functionality. |
|
|
837 | |
|
|
838 | You I<must not> change the priority of a watcher as long as it is active or |
|
|
839 | pending. |
|
|
840 | |
|
|
841 | The default priority used by watchers when no priority has been set is |
|
|
842 | always C<0>, which is supposed to not be too high and not be too low :). |
|
|
843 | |
|
|
844 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
|
|
845 | fine, as long as you do not mind that the priority value you query might |
|
|
846 | or might not have been adjusted to be within valid range. |
|
|
847 | |
|
|
848 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
|
|
849 | |
|
|
850 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
|
|
851 | C<loop> nor C<revents> need to be valid as long as the watcher callback |
|
|
852 | can deal with that fact. |
|
|
853 | |
|
|
854 | =item int ev_clear_pending (loop, ev_TYPE *watcher) |
|
|
855 | |
|
|
856 | If the watcher is pending, this function returns clears its pending status |
|
|
857 | and returns its C<revents> bitset (as if its callback was invoked). If the |
|
|
858 | watcher isn't pending it does nothing and returns C<0>. |
738 | |
859 | |
739 | =back |
860 | =back |
740 | |
861 | |
741 | |
862 | |
742 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
863 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
848 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
969 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
849 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
970 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
850 | |
971 | |
851 | If you cannot run the fd in non-blocking mode (for example you should not |
972 | If you cannot run the fd in non-blocking mode (for example you should not |
852 | play around with an Xlib connection), then you have to seperately re-test |
973 | play around with an Xlib connection), then you have to seperately re-test |
853 | wether a file descriptor is really ready with a known-to-be good interface |
974 | whether a file descriptor is really ready with a known-to-be good interface |
854 | such as poll (fortunately in our Xlib example, Xlib already does this on |
975 | such as poll (fortunately in our Xlib example, Xlib already does this on |
855 | its own, so its quite safe to use). |
976 | its own, so its quite safe to use). |
|
|
977 | |
|
|
978 | =head3 The special problem of disappearing file descriptors |
|
|
979 | |
|
|
980 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
|
|
981 | descriptor (either by calling C<close> explicitly or by any other means, |
|
|
982 | such as C<dup>). The reason is that you register interest in some file |
|
|
983 | descriptor, but when it goes away, the operating system will silently drop |
|
|
984 | this interest. If another file descriptor with the same number then is |
|
|
985 | registered with libev, there is no efficient way to see that this is, in |
|
|
986 | fact, a different file descriptor. |
|
|
987 | |
|
|
988 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
989 | the following policy: Each time C<ev_io_set> is being called, libev |
|
|
990 | will assume that this is potentially a new file descriptor, otherwise |
|
|
991 | it is assumed that the file descriptor stays the same. That means that |
|
|
992 | you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the |
|
|
993 | descriptor even if the file descriptor number itself did not change. |
|
|
994 | |
|
|
995 | This is how one would do it normally anyway, the important point is that |
|
|
996 | the libev application should not optimise around libev but should leave |
|
|
997 | optimisations to libev. |
|
|
998 | |
|
|
999 | =head3 The special problem of dup'ed file descriptors |
|
|
1000 | |
|
|
1001 | Some backends (e.g. epoll), cannot register events for file descriptors, |
|
|
1002 | but only events for the underlying file descriptions. That menas when you |
|
|
1003 | have C<dup ()>'ed file descriptors and register events for them, only one |
|
|
1004 | file descriptor might actually receive events. |
|
|
1005 | |
|
|
1006 | There is no workaorund possible except not registering events |
|
|
1007 | for potentially C<dup ()>'ed file descriptors or to resort to |
|
|
1008 | C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>. |
|
|
1009 | |
|
|
1010 | =head3 The special problem of fork |
|
|
1011 | |
|
|
1012 | Some backends (epoll, kqueue) do not support C<fork ()> at all or exhibit |
|
|
1013 | useless behaviour. Libev fully supports fork, but needs to be told about |
|
|
1014 | it in the child. |
|
|
1015 | |
|
|
1016 | To support fork in your programs, you either have to call |
|
|
1017 | C<ev_default_fork ()> or C<ev_loop_fork ()> after a fork in the child, |
|
|
1018 | enable C<EVFLAG_FORKCHECK>, or resort to C<EVBACKEND_SELECT> or |
|
|
1019 | C<EVBACKEND_POLL>. |
|
|
1020 | |
|
|
1021 | |
|
|
1022 | =head3 Watcher-Specific Functions |
856 | |
1023 | |
857 | =over 4 |
1024 | =over 4 |
858 | |
1025 | |
859 | =item ev_io_init (ev_io *, callback, int fd, int events) |
1026 | =item ev_io_init (ev_io *, callback, int fd, int events) |
860 | |
1027 | |
… | |
… | |
913 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
1080 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
914 | |
1081 | |
915 | The callback is guarenteed to be invoked only when its timeout has passed, |
1082 | The callback is guarenteed to be invoked only when its timeout has passed, |
916 | but if multiple timers become ready during the same loop iteration then |
1083 | but if multiple timers become ready during the same loop iteration then |
917 | order of execution is undefined. |
1084 | order of execution is undefined. |
|
|
1085 | |
|
|
1086 | =head3 Watcher-Specific Functions and Data Members |
918 | |
1087 | |
919 | =over 4 |
1088 | =over 4 |
920 | |
1089 | |
921 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
1090 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
922 | |
1091 | |
… | |
… | |
1018 | but on wallclock time (absolute time). You can tell a periodic watcher |
1187 | but on wallclock time (absolute time). You can tell a periodic watcher |
1019 | to trigger "at" some specific point in time. For example, if you tell a |
1188 | to trigger "at" some specific point in time. For example, if you tell a |
1020 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1189 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1021 | + 10.>) and then reset your system clock to the last year, then it will |
1190 | + 10.>) and then reset your system clock to the last year, then it will |
1022 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1191 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1023 | roughly 10 seconds later and of course not if you reset your system time |
1192 | roughly 10 seconds later). |
1024 | again). |
|
|
1025 | |
1193 | |
1026 | They can also be used to implement vastly more complex timers, such as |
1194 | They can also be used to implement vastly more complex timers, such as |
1027 | triggering an event on eahc midnight, local time. |
1195 | triggering an event on each midnight, local time or other, complicated, |
|
|
1196 | rules. |
1028 | |
1197 | |
1029 | As with timers, the callback is guarenteed to be invoked only when the |
1198 | As with timers, the callback is guarenteed to be invoked only when the |
1030 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1199 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1031 | during the same loop iteration then order of execution is undefined. |
1200 | during the same loop iteration then order of execution is undefined. |
1032 | |
1201 | |
|
|
1202 | =head3 Watcher-Specific Functions and Data Members |
|
|
1203 | |
1033 | =over 4 |
1204 | =over 4 |
1034 | |
1205 | |
1035 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1206 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1036 | |
1207 | |
1037 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
1208 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
… | |
… | |
1039 | Lots of arguments, lets sort it out... There are basically three modes of |
1210 | Lots of arguments, lets sort it out... There are basically three modes of |
1040 | operation, and we will explain them from simplest to complex: |
1211 | operation, and we will explain them from simplest to complex: |
1041 | |
1212 | |
1042 | =over 4 |
1213 | =over 4 |
1043 | |
1214 | |
1044 | =item * absolute timer (interval = reschedule_cb = 0) |
1215 | =item * absolute timer (at = time, interval = reschedule_cb = 0) |
1045 | |
1216 | |
1046 | In this configuration the watcher triggers an event at the wallclock time |
1217 | In this configuration the watcher triggers an event at the wallclock time |
1047 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1218 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1048 | that is, if it is to be run at January 1st 2011 then it will run when the |
1219 | that is, if it is to be run at January 1st 2011 then it will run when the |
1049 | system time reaches or surpasses this time. |
1220 | system time reaches or surpasses this time. |
1050 | |
1221 | |
1051 | =item * non-repeating interval timer (interval > 0, reschedule_cb = 0) |
1222 | =item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1052 | |
1223 | |
1053 | In this mode the watcher will always be scheduled to time out at the next |
1224 | In this mode the watcher will always be scheduled to time out at the next |
1054 | C<at + N * interval> time (for some integer N) and then repeat, regardless |
1225 | C<at + N * interval> time (for some integer N, which can also be negative) |
1055 | of any time jumps. |
1226 | and then repeat, regardless of any time jumps. |
1056 | |
1227 | |
1057 | This can be used to create timers that do not drift with respect to system |
1228 | This can be used to create timers that do not drift with respect to system |
1058 | time: |
1229 | time: |
1059 | |
1230 | |
1060 | ev_periodic_set (&periodic, 0., 3600., 0); |
1231 | ev_periodic_set (&periodic, 0., 3600., 0); |
… | |
… | |
1066 | |
1237 | |
1067 | Another way to think about it (for the mathematically inclined) is that |
1238 | Another way to think about it (for the mathematically inclined) is that |
1068 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1239 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1069 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1240 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1070 | |
1241 | |
|
|
1242 | For numerical stability it is preferable that the C<at> value is near |
|
|
1243 | C<ev_now ()> (the current time), but there is no range requirement for |
|
|
1244 | this value. |
|
|
1245 | |
1071 | =item * manual reschedule mode (reschedule_cb = callback) |
1246 | =item * manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
1072 | |
1247 | |
1073 | In this mode the values for C<interval> and C<at> are both being |
1248 | In this mode the values for C<interval> and C<at> are both being |
1074 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1249 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1075 | reschedule callback will be called with the watcher as first, and the |
1250 | reschedule callback will be called with the watcher as first, and the |
1076 | current time as second argument. |
1251 | current time as second argument. |
1077 | |
1252 | |
1078 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1253 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1079 | ever, or make any event loop modifications>. If you need to stop it, |
1254 | ever, or make any event loop modifications>. If you need to stop it, |
1080 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1255 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1081 | starting a prepare watcher). |
1256 | starting an C<ev_prepare> watcher, which is legal). |
1082 | |
1257 | |
1083 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1258 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1084 | ev_tstamp now)>, e.g.: |
1259 | ev_tstamp now)>, e.g.: |
1085 | |
1260 | |
1086 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
1261 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
1109 | Simply stops and restarts the periodic watcher again. This is only useful |
1284 | Simply stops and restarts the periodic watcher again. This is only useful |
1110 | when you changed some parameters or the reschedule callback would return |
1285 | when you changed some parameters or the reschedule callback would return |
1111 | a different time than the last time it was called (e.g. in a crond like |
1286 | a different time than the last time it was called (e.g. in a crond like |
1112 | program when the crontabs have changed). |
1287 | program when the crontabs have changed). |
1113 | |
1288 | |
|
|
1289 | =item ev_tstamp offset [read-write] |
|
|
1290 | |
|
|
1291 | When repeating, this contains the offset value, otherwise this is the |
|
|
1292 | absolute point in time (the C<at> value passed to C<ev_periodic_set>). |
|
|
1293 | |
|
|
1294 | Can be modified any time, but changes only take effect when the periodic |
|
|
1295 | timer fires or C<ev_periodic_again> is being called. |
|
|
1296 | |
1114 | =item ev_tstamp interval [read-write] |
1297 | =item ev_tstamp interval [read-write] |
1115 | |
1298 | |
1116 | The current interval value. Can be modified any time, but changes only |
1299 | The current interval value. Can be modified any time, but changes only |
1117 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1300 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1118 | called. |
1301 | called. |
… | |
… | |
1120 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
1303 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
1121 | |
1304 | |
1122 | The current reschedule callback, or C<0>, if this functionality is |
1305 | The current reschedule callback, or C<0>, if this functionality is |
1123 | switched off. Can be changed any time, but changes only take effect when |
1306 | switched off. Can be changed any time, but changes only take effect when |
1124 | the periodic timer fires or C<ev_periodic_again> is being called. |
1307 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
|
1308 | |
|
|
1309 | =item ev_tstamp at [read-only] |
|
|
1310 | |
|
|
1311 | When active, contains the absolute time that the watcher is supposed to |
|
|
1312 | trigger next. |
1125 | |
1313 | |
1126 | =back |
1314 | =back |
1127 | |
1315 | |
1128 | Example: Call a callback every hour, or, more precisely, whenever the |
1316 | Example: Call a callback every hour, or, more precisely, whenever the |
1129 | system clock is divisible by 3600. The callback invocation times have |
1317 | system clock is divisible by 3600. The callback invocation times have |
… | |
… | |
1171 | with the kernel (thus it coexists with your own signal handlers as long |
1359 | with the kernel (thus it coexists with your own signal handlers as long |
1172 | as you don't register any with libev). Similarly, when the last signal |
1360 | as you don't register any with libev). Similarly, when the last signal |
1173 | watcher for a signal is stopped libev will reset the signal handler to |
1361 | watcher for a signal is stopped libev will reset the signal handler to |
1174 | SIG_DFL (regardless of what it was set to before). |
1362 | SIG_DFL (regardless of what it was set to before). |
1175 | |
1363 | |
|
|
1364 | =head3 Watcher-Specific Functions and Data Members |
|
|
1365 | |
1176 | =over 4 |
1366 | =over 4 |
1177 | |
1367 | |
1178 | =item ev_signal_init (ev_signal *, callback, int signum) |
1368 | =item ev_signal_init (ev_signal *, callback, int signum) |
1179 | |
1369 | |
1180 | =item ev_signal_set (ev_signal *, int signum) |
1370 | =item ev_signal_set (ev_signal *, int signum) |
… | |
… | |
1191 | |
1381 | |
1192 | =head2 C<ev_child> - watch out for process status changes |
1382 | =head2 C<ev_child> - watch out for process status changes |
1193 | |
1383 | |
1194 | Child watchers trigger when your process receives a SIGCHLD in response to |
1384 | Child watchers trigger when your process receives a SIGCHLD in response to |
1195 | some child status changes (most typically when a child of yours dies). |
1385 | some child status changes (most typically when a child of yours dies). |
|
|
1386 | |
|
|
1387 | =head3 Watcher-Specific Functions and Data Members |
1196 | |
1388 | |
1197 | =over 4 |
1389 | =over 4 |
1198 | |
1390 | |
1199 | =item ev_child_init (ev_child *, callback, int pid) |
1391 | =item ev_child_init (ev_child *, callback, int pid) |
1200 | |
1392 | |
… | |
… | |
1268 | reader). Inotify will be used to give hints only and should not change the |
1460 | reader). Inotify will be used to give hints only and should not change the |
1269 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1461 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
1270 | to fall back to regular polling again even with inotify, but changes are |
1462 | to fall back to regular polling again even with inotify, but changes are |
1271 | usually detected immediately, and if the file exists there will be no |
1463 | usually detected immediately, and if the file exists there will be no |
1272 | polling. |
1464 | polling. |
|
|
1465 | |
|
|
1466 | =head3 Watcher-Specific Functions and Data Members |
1273 | |
1467 | |
1274 | =over 4 |
1468 | =over 4 |
1275 | |
1469 | |
1276 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1470 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1277 | |
1471 | |
… | |
… | |
1341 | ev_stat_start (loop, &passwd); |
1535 | ev_stat_start (loop, &passwd); |
1342 | |
1536 | |
1343 | |
1537 | |
1344 | =head2 C<ev_idle> - when you've got nothing better to do... |
1538 | =head2 C<ev_idle> - when you've got nothing better to do... |
1345 | |
1539 | |
1346 | Idle watchers trigger events when there are no other events are pending |
1540 | Idle watchers trigger events when no other events of the same or higher |
1347 | (prepare, check and other idle watchers do not count). That is, as long |
1541 | priority are pending (prepare, check and other idle watchers do not |
1348 | as your process is busy handling sockets or timeouts (or even signals, |
1542 | count). |
1349 | imagine) it will not be triggered. But when your process is idle all idle |
1543 | |
1350 | watchers are being called again and again, once per event loop iteration - |
1544 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1545 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1546 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1547 | are pending), the idle watchers are being called once per event loop |
1351 | until stopped, that is, or your process receives more events and becomes |
1548 | iteration - until stopped, that is, or your process receives more events |
1352 | busy. |
1549 | and becomes busy again with higher priority stuff. |
1353 | |
1550 | |
1354 | The most noteworthy effect is that as long as any idle watchers are |
1551 | The most noteworthy effect is that as long as any idle watchers are |
1355 | active, the process will not block when waiting for new events. |
1552 | active, the process will not block when waiting for new events. |
1356 | |
1553 | |
1357 | Apart from keeping your process non-blocking (which is a useful |
1554 | Apart from keeping your process non-blocking (which is a useful |
1358 | effect on its own sometimes), idle watchers are a good place to do |
1555 | effect on its own sometimes), idle watchers are a good place to do |
1359 | "pseudo-background processing", or delay processing stuff to after the |
1556 | "pseudo-background processing", or delay processing stuff to after the |
1360 | event loop has handled all outstanding events. |
1557 | event loop has handled all outstanding events. |
|
|
1558 | |
|
|
1559 | =head3 Watcher-Specific Functions and Data Members |
1361 | |
1560 | |
1362 | =over 4 |
1561 | =over 4 |
1363 | |
1562 | |
1364 | =item ev_idle_init (ev_signal *, callback) |
1563 | =item ev_idle_init (ev_signal *, callback) |
1365 | |
1564 | |
… | |
… | |
1423 | with priority higher than or equal to the event loop and one coroutine |
1622 | with priority higher than or equal to the event loop and one coroutine |
1424 | of lower priority, but only once, using idle watchers to keep the event |
1623 | of lower priority, but only once, using idle watchers to keep the event |
1425 | loop from blocking if lower-priority coroutines are active, thus mapping |
1624 | loop from blocking if lower-priority coroutines are active, thus mapping |
1426 | low-priority coroutines to idle/background tasks). |
1625 | low-priority coroutines to idle/background tasks). |
1427 | |
1626 | |
|
|
1627 | It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>) |
|
|
1628 | priority, to ensure that they are being run before any other watchers |
|
|
1629 | after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers, |
|
|
1630 | too) should not activate ("feed") events into libev. While libev fully |
|
|
1631 | supports this, they will be called before other C<ev_check> watchers |
|
|
1632 | did their job. As C<ev_check> watchers are often used to embed other |
|
|
1633 | (non-libev) event loops those other event loops might be in an unusable |
|
|
1634 | state until their C<ev_check> watcher ran (always remind yourself to |
|
|
1635 | coexist peacefully with others). |
|
|
1636 | |
|
|
1637 | =head3 Watcher-Specific Functions and Data Members |
|
|
1638 | |
1428 | =over 4 |
1639 | =over 4 |
1429 | |
1640 | |
1430 | =item ev_prepare_init (ev_prepare *, callback) |
1641 | =item ev_prepare_init (ev_prepare *, callback) |
1431 | |
1642 | |
1432 | =item ev_check_init (ev_check *, callback) |
1643 | =item ev_check_init (ev_check *, callback) |
… | |
… | |
1435 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1646 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1436 | macros, but using them is utterly, utterly and completely pointless. |
1647 | macros, but using them is utterly, utterly and completely pointless. |
1437 | |
1648 | |
1438 | =back |
1649 | =back |
1439 | |
1650 | |
1440 | Example: To include a library such as adns, you would add IO watchers |
1651 | There are a number of principal ways to embed other event loops or modules |
1441 | and a timeout watcher in a prepare handler, as required by libadns, and |
1652 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1653 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
|
|
1654 | use for an actually working example. Another Perl module named C<EV::Glib> |
|
|
1655 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
|
|
1656 | into the Glib event loop). |
|
|
1657 | |
|
|
1658 | Method 1: Add IO watchers and a timeout watcher in a prepare handler, |
1442 | in a check watcher, destroy them and call into libadns. What follows is |
1659 | and in a check watcher, destroy them and call into libadns. What follows |
1443 | pseudo-code only of course: |
1660 | is pseudo-code only of course. This requires you to either use a low |
|
|
1661 | priority for the check watcher or use C<ev_clear_pending> explicitly, as |
|
|
1662 | the callbacks for the IO/timeout watchers might not have been called yet. |
1444 | |
1663 | |
1445 | static ev_io iow [nfd]; |
1664 | static ev_io iow [nfd]; |
1446 | static ev_timer tw; |
1665 | static ev_timer tw; |
1447 | |
1666 | |
1448 | static void |
1667 | static void |
1449 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1668 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1450 | { |
1669 | { |
1451 | // set the relevant poll flags |
|
|
1452 | // could also call adns_processreadable etc. here |
|
|
1453 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1454 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1455 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1456 | } |
1670 | } |
1457 | |
1671 | |
1458 | // create io watchers for each fd and a timer before blocking |
1672 | // create io watchers for each fd and a timer before blocking |
1459 | static void |
1673 | static void |
1460 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1674 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1461 | { |
1675 | { |
1462 | int timeout = 3600000;truct pollfd fds [nfd]; |
1676 | int timeout = 3600000; |
|
|
1677 | struct pollfd fds [nfd]; |
1463 | // actual code will need to loop here and realloc etc. |
1678 | // actual code will need to loop here and realloc etc. |
1464 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1679 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1465 | |
1680 | |
1466 | /* the callback is illegal, but won't be called as we stop during check */ |
1681 | /* the callback is illegal, but won't be called as we stop during check */ |
1467 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1682 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1468 | ev_timer_start (loop, &tw); |
1683 | ev_timer_start (loop, &tw); |
1469 | |
1684 | |
1470 | // create on ev_io per pollfd |
1685 | // create one ev_io per pollfd |
1471 | for (int i = 0; i < nfd; ++i) |
1686 | for (int i = 0; i < nfd; ++i) |
1472 | { |
1687 | { |
1473 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1688 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1474 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1689 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1475 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1690 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1476 | |
1691 | |
1477 | fds [i].revents = 0; |
1692 | fds [i].revents = 0; |
1478 | iow [i].data = fds + i; |
|
|
1479 | ev_io_start (loop, iow + i); |
1693 | ev_io_start (loop, iow + i); |
1480 | } |
1694 | } |
1481 | } |
1695 | } |
1482 | |
1696 | |
1483 | // stop all watchers after blocking |
1697 | // stop all watchers after blocking |
… | |
… | |
1485 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1699 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1486 | { |
1700 | { |
1487 | ev_timer_stop (loop, &tw); |
1701 | ev_timer_stop (loop, &tw); |
1488 | |
1702 | |
1489 | for (int i = 0; i < nfd; ++i) |
1703 | for (int i = 0; i < nfd; ++i) |
|
|
1704 | { |
|
|
1705 | // set the relevant poll flags |
|
|
1706 | // could also call adns_processreadable etc. here |
|
|
1707 | struct pollfd *fd = fds + i; |
|
|
1708 | int revents = ev_clear_pending (iow + i); |
|
|
1709 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1710 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1711 | |
|
|
1712 | // now stop the watcher |
1490 | ev_io_stop (loop, iow + i); |
1713 | ev_io_stop (loop, iow + i); |
|
|
1714 | } |
1491 | |
1715 | |
1492 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1716 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1717 | } |
|
|
1718 | |
|
|
1719 | Method 2: This would be just like method 1, but you run C<adns_afterpoll> |
|
|
1720 | in the prepare watcher and would dispose of the check watcher. |
|
|
1721 | |
|
|
1722 | Method 3: If the module to be embedded supports explicit event |
|
|
1723 | notification (adns does), you can also make use of the actual watcher |
|
|
1724 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1725 | |
|
|
1726 | static void |
|
|
1727 | timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1728 | { |
|
|
1729 | adns_state ads = (adns_state)w->data; |
|
|
1730 | update_now (EV_A); |
|
|
1731 | |
|
|
1732 | adns_processtimeouts (ads, &tv_now); |
|
|
1733 | } |
|
|
1734 | |
|
|
1735 | static void |
|
|
1736 | io_cb (EV_P_ ev_io *w, int revents) |
|
|
1737 | { |
|
|
1738 | adns_state ads = (adns_state)w->data; |
|
|
1739 | update_now (EV_A); |
|
|
1740 | |
|
|
1741 | if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1742 | if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1743 | } |
|
|
1744 | |
|
|
1745 | // do not ever call adns_afterpoll |
|
|
1746 | |
|
|
1747 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1748 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1749 | their poll function. The drawback with this solution is that the main |
|
|
1750 | loop is now no longer controllable by EV. The C<Glib::EV> module does |
|
|
1751 | this. |
|
|
1752 | |
|
|
1753 | static gint |
|
|
1754 | event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1755 | { |
|
|
1756 | int got_events = 0; |
|
|
1757 | |
|
|
1758 | for (n = 0; n < nfds; ++n) |
|
|
1759 | // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1760 | |
|
|
1761 | if (timeout >= 0) |
|
|
1762 | // create/start timer |
|
|
1763 | |
|
|
1764 | // poll |
|
|
1765 | ev_loop (EV_A_ 0); |
|
|
1766 | |
|
|
1767 | // stop timer again |
|
|
1768 | if (timeout >= 0) |
|
|
1769 | ev_timer_stop (EV_A_ &to); |
|
|
1770 | |
|
|
1771 | // stop io watchers again - their callbacks should have set |
|
|
1772 | for (n = 0; n < nfds; ++n) |
|
|
1773 | ev_io_stop (EV_A_ iow [n]); |
|
|
1774 | |
|
|
1775 | return got_events; |
1493 | } |
1776 | } |
1494 | |
1777 | |
1495 | |
1778 | |
1496 | =head2 C<ev_embed> - when one backend isn't enough... |
1779 | =head2 C<ev_embed> - when one backend isn't enough... |
1497 | |
1780 | |
… | |
… | |
1561 | ev_embed_start (loop_hi, &embed); |
1844 | ev_embed_start (loop_hi, &embed); |
1562 | } |
1845 | } |
1563 | else |
1846 | else |
1564 | loop_lo = loop_hi; |
1847 | loop_lo = loop_hi; |
1565 | |
1848 | |
|
|
1849 | =head3 Watcher-Specific Functions and Data Members |
|
|
1850 | |
1566 | =over 4 |
1851 | =over 4 |
1567 | |
1852 | |
1568 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1853 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1569 | |
1854 | |
1570 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
1855 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
… | |
… | |
1579 | |
1864 | |
1580 | Make a single, non-blocking sweep over the embedded loop. This works |
1865 | Make a single, non-blocking sweep over the embedded loop. This works |
1581 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1866 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1582 | apropriate way for embedded loops. |
1867 | apropriate way for embedded loops. |
1583 | |
1868 | |
1584 | =item struct ev_loop *loop [read-only] |
1869 | =item struct ev_loop *other [read-only] |
1585 | |
1870 | |
1586 | The embedded event loop. |
1871 | The embedded event loop. |
1587 | |
1872 | |
1588 | =back |
1873 | =back |
1589 | |
1874 | |
… | |
… | |
1596 | event loop blocks next and before C<ev_check> watchers are being called, |
1881 | event loop blocks next and before C<ev_check> watchers are being called, |
1597 | and only in the child after the fork. If whoever good citizen calling |
1882 | and only in the child after the fork. If whoever good citizen calling |
1598 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1883 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1599 | handlers will be invoked, too, of course. |
1884 | handlers will be invoked, too, of course. |
1600 | |
1885 | |
|
|
1886 | =head3 Watcher-Specific Functions and Data Members |
|
|
1887 | |
1601 | =over 4 |
1888 | =over 4 |
1602 | |
1889 | |
1603 | =item ev_fork_init (ev_signal *, callback) |
1890 | =item ev_fork_init (ev_signal *, callback) |
1604 | |
1891 | |
1605 | Initialises and configures the fork watcher - it has no parameters of any |
1892 | Initialises and configures the fork watcher - it has no parameters of any |
… | |
… | |
1701 | |
1988 | |
1702 | To use it, |
1989 | To use it, |
1703 | |
1990 | |
1704 | #include <ev++.h> |
1991 | #include <ev++.h> |
1705 | |
1992 | |
1706 | (it is not installed by default). This automatically includes F<ev.h> |
1993 | This automatically includes F<ev.h> and puts all of its definitions (many |
1707 | and puts all of its definitions (many of them macros) into the global |
1994 | of them macros) into the global namespace. All C++ specific things are |
1708 | namespace. All C++ specific things are put into the C<ev> namespace. |
1995 | put into the C<ev> namespace. It should support all the same embedding |
|
|
1996 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
1709 | |
1997 | |
1710 | It should support all the same embedding options as F<ev.h>, most notably |
1998 | Care has been taken to keep the overhead low. The only data member the C++ |
1711 | C<EV_MULTIPLICITY>. |
1999 | classes add (compared to plain C-style watchers) is the event loop pointer |
|
|
2000 | that the watcher is associated with (or no additional members at all if |
|
|
2001 | you disable C<EV_MULTIPLICITY> when embedding libev). |
|
|
2002 | |
|
|
2003 | Currently, functions, and static and non-static member functions can be |
|
|
2004 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2005 | need one additional pointer for context. If you need support for other |
|
|
2006 | types of functors please contact the author (preferably after implementing |
|
|
2007 | it). |
1712 | |
2008 | |
1713 | Here is a list of things available in the C<ev> namespace: |
2009 | Here is a list of things available in the C<ev> namespace: |
1714 | |
2010 | |
1715 | =over 4 |
2011 | =over 4 |
1716 | |
2012 | |
… | |
… | |
1732 | |
2028 | |
1733 | All of those classes have these methods: |
2029 | All of those classes have these methods: |
1734 | |
2030 | |
1735 | =over 4 |
2031 | =over 4 |
1736 | |
2032 | |
1737 | =item ev::TYPE::TYPE (object *, object::method *) |
2033 | =item ev::TYPE::TYPE () |
1738 | |
2034 | |
1739 | =item ev::TYPE::TYPE (object *, object::method *, struct ev_loop *) |
2035 | =item ev::TYPE::TYPE (struct ev_loop *) |
1740 | |
2036 | |
1741 | =item ev::TYPE::~TYPE |
2037 | =item ev::TYPE::~TYPE |
1742 | |
2038 | |
1743 | The constructor takes a pointer to an object and a method pointer to |
2039 | The constructor (optionally) takes an event loop to associate the watcher |
1744 | the event handler callback to call in this class. The constructor calls |
2040 | with. If it is omitted, it will use C<EV_DEFAULT>. |
1745 | C<ev_init> for you, which means you have to call the C<set> method |
2041 | |
1746 | before starting it. If you do not specify a loop then the constructor |
2042 | The constructor calls C<ev_init> for you, which means you have to call the |
1747 | automatically associates the default loop with this watcher. |
2043 | C<set> method before starting it. |
|
|
2044 | |
|
|
2045 | It will not set a callback, however: You have to call the templated C<set> |
|
|
2046 | method to set a callback before you can start the watcher. |
|
|
2047 | |
|
|
2048 | (The reason why you have to use a method is a limitation in C++ which does |
|
|
2049 | not allow explicit template arguments for constructors). |
1748 | |
2050 | |
1749 | The destructor automatically stops the watcher if it is active. |
2051 | The destructor automatically stops the watcher if it is active. |
|
|
2052 | |
|
|
2053 | =item w->set<class, &class::method> (object *) |
|
|
2054 | |
|
|
2055 | This method sets the callback method to call. The method has to have a |
|
|
2056 | signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as |
|
|
2057 | first argument and the C<revents> as second. The object must be given as |
|
|
2058 | parameter and is stored in the C<data> member of the watcher. |
|
|
2059 | |
|
|
2060 | This method synthesizes efficient thunking code to call your method from |
|
|
2061 | the C callback that libev requires. If your compiler can inline your |
|
|
2062 | callback (i.e. it is visible to it at the place of the C<set> call and |
|
|
2063 | your compiler is good :), then the method will be fully inlined into the |
|
|
2064 | thunking function, making it as fast as a direct C callback. |
|
|
2065 | |
|
|
2066 | Example: simple class declaration and watcher initialisation |
|
|
2067 | |
|
|
2068 | struct myclass |
|
|
2069 | { |
|
|
2070 | void io_cb (ev::io &w, int revents) { } |
|
|
2071 | } |
|
|
2072 | |
|
|
2073 | myclass obj; |
|
|
2074 | ev::io iow; |
|
|
2075 | iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2076 | |
|
|
2077 | =item w->set<function> (void *data = 0) |
|
|
2078 | |
|
|
2079 | Also sets a callback, but uses a static method or plain function as |
|
|
2080 | callback. The optional C<data> argument will be stored in the watcher's |
|
|
2081 | C<data> member and is free for you to use. |
|
|
2082 | |
|
|
2083 | The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>. |
|
|
2084 | |
|
|
2085 | See the method-C<set> above for more details. |
|
|
2086 | |
|
|
2087 | Example: |
|
|
2088 | |
|
|
2089 | static void io_cb (ev::io &w, int revents) { } |
|
|
2090 | iow.set <io_cb> (); |
1750 | |
2091 | |
1751 | =item w->set (struct ev_loop *) |
2092 | =item w->set (struct ev_loop *) |
1752 | |
2093 | |
1753 | Associates a different C<struct ev_loop> with this watcher. You can only |
2094 | Associates a different C<struct ev_loop> with this watcher. You can only |
1754 | do this when the watcher is inactive (and not pending either). |
2095 | do this when the watcher is inactive (and not pending either). |
1755 | |
2096 | |
1756 | =item w->set ([args]) |
2097 | =item w->set ([args]) |
1757 | |
2098 | |
1758 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
2099 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
1759 | called at least once. Unlike the C counterpart, an active watcher gets |
2100 | called at least once. Unlike the C counterpart, an active watcher gets |
1760 | automatically stopped and restarted. |
2101 | automatically stopped and restarted when reconfiguring it with this |
|
|
2102 | method. |
1761 | |
2103 | |
1762 | =item w->start () |
2104 | =item w->start () |
1763 | |
2105 | |
1764 | Starts the watcher. Note that there is no C<loop> argument as the |
2106 | Starts the watcher. Note that there is no C<loop> argument, as the |
1765 | constructor already takes the loop. |
2107 | constructor already stores the event loop. |
1766 | |
2108 | |
1767 | =item w->stop () |
2109 | =item w->stop () |
1768 | |
2110 | |
1769 | Stops the watcher if it is active. Again, no C<loop> argument. |
2111 | Stops the watcher if it is active. Again, no C<loop> argument. |
1770 | |
2112 | |
1771 | =item w->again () C<ev::timer>, C<ev::periodic> only |
2113 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
1772 | |
2114 | |
1773 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
2115 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
1774 | C<ev_TYPE_again> function. |
2116 | C<ev_TYPE_again> function. |
1775 | |
2117 | |
1776 | =item w->sweep () C<ev::embed> only |
2118 | =item w->sweep () (C<ev::embed> only) |
1777 | |
2119 | |
1778 | Invokes C<ev_embed_sweep>. |
2120 | Invokes C<ev_embed_sweep>. |
1779 | |
2121 | |
1780 | =item w->update () C<ev::stat> only |
2122 | =item w->update () (C<ev::stat> only) |
1781 | |
2123 | |
1782 | Invokes C<ev_stat_stat>. |
2124 | Invokes C<ev_stat_stat>. |
1783 | |
2125 | |
1784 | =back |
2126 | =back |
1785 | |
2127 | |
… | |
… | |
1795 | |
2137 | |
1796 | myclass (); |
2138 | myclass (); |
1797 | } |
2139 | } |
1798 | |
2140 | |
1799 | myclass::myclass (int fd) |
2141 | myclass::myclass (int fd) |
1800 | : io (this, &myclass::io_cb), |
|
|
1801 | idle (this, &myclass::idle_cb) |
|
|
1802 | { |
2142 | { |
|
|
2143 | io .set <myclass, &myclass::io_cb > (this); |
|
|
2144 | idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2145 | |
1803 | io.start (fd, ev::READ); |
2146 | io.start (fd, ev::READ); |
1804 | } |
2147 | } |
1805 | |
2148 | |
1806 | |
2149 | |
1807 | =head1 MACRO MAGIC |
2150 | =head1 MACRO MAGIC |
1808 | |
2151 | |
1809 | Libev can be compiled with a variety of options, the most fundemantal is |
2152 | Libev can be compiled with a variety of options, the most fundamantal |
1810 | C<EV_MULTIPLICITY>. This option determines wether (most) functions and |
2153 | of which is C<EV_MULTIPLICITY>. This option determines whether (most) |
1811 | callbacks have an initial C<struct ev_loop *> argument. |
2154 | functions and callbacks have an initial C<struct ev_loop *> argument. |
1812 | |
2155 | |
1813 | To make it easier to write programs that cope with either variant, the |
2156 | To make it easier to write programs that cope with either variant, the |
1814 | following macros are defined: |
2157 | following macros are defined: |
1815 | |
2158 | |
1816 | =over 4 |
2159 | =over 4 |
… | |
… | |
1848 | Similar to the other two macros, this gives you the value of the default |
2191 | Similar to the other two macros, this gives you the value of the default |
1849 | loop, if multiple loops are supported ("ev loop default"). |
2192 | loop, if multiple loops are supported ("ev loop default"). |
1850 | |
2193 | |
1851 | =back |
2194 | =back |
1852 | |
2195 | |
1853 | Example: Declare and initialise a check watcher, working regardless of |
2196 | Example: Declare and initialise a check watcher, utilising the above |
1854 | wether multiple loops are supported or not. |
2197 | macros so it will work regardless of whether multiple loops are supported |
|
|
2198 | or not. |
1855 | |
2199 | |
1856 | static void |
2200 | static void |
1857 | check_cb (EV_P_ ev_timer *w, int revents) |
2201 | check_cb (EV_P_ ev_timer *w, int revents) |
1858 | { |
2202 | { |
1859 | ev_check_stop (EV_A_ w); |
2203 | ev_check_stop (EV_A_ w); |
… | |
… | |
1862 | ev_check check; |
2206 | ev_check check; |
1863 | ev_check_init (&check, check_cb); |
2207 | ev_check_init (&check, check_cb); |
1864 | ev_check_start (EV_DEFAULT_ &check); |
2208 | ev_check_start (EV_DEFAULT_ &check); |
1865 | ev_loop (EV_DEFAULT_ 0); |
2209 | ev_loop (EV_DEFAULT_ 0); |
1866 | |
2210 | |
1867 | |
|
|
1868 | =head1 EMBEDDING |
2211 | =head1 EMBEDDING |
1869 | |
2212 | |
1870 | Libev can (and often is) directly embedded into host |
2213 | Libev can (and often is) directly embedded into host |
1871 | applications. Examples of applications that embed it include the Deliantra |
2214 | applications. Examples of applications that embed it include the Deliantra |
1872 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
2215 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1873 | and rxvt-unicode. |
2216 | and rxvt-unicode. |
1874 | |
2217 | |
1875 | The goal is to enable you to just copy the neecssary files into your |
2218 | The goal is to enable you to just copy the necessary files into your |
1876 | source directory without having to change even a single line in them, so |
2219 | source directory without having to change even a single line in them, so |
1877 | you can easily upgrade by simply copying (or having a checked-out copy of |
2220 | you can easily upgrade by simply copying (or having a checked-out copy of |
1878 | libev somewhere in your source tree). |
2221 | libev somewhere in your source tree). |
1879 | |
2222 | |
1880 | =head2 FILESETS |
2223 | =head2 FILESETS |
… | |
… | |
1911 | ev_vars.h |
2254 | ev_vars.h |
1912 | ev_wrap.h |
2255 | ev_wrap.h |
1913 | |
2256 | |
1914 | ev_win32.c required on win32 platforms only |
2257 | ev_win32.c required on win32 platforms only |
1915 | |
2258 | |
1916 | ev_select.c only when select backend is enabled (which is by default) |
2259 | ev_select.c only when select backend is enabled (which is enabled by default) |
1917 | ev_poll.c only when poll backend is enabled (disabled by default) |
2260 | ev_poll.c only when poll backend is enabled (disabled by default) |
1918 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2261 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1919 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2262 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1920 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
2263 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1921 | |
2264 | |
… | |
… | |
1970 | |
2313 | |
1971 | If defined to be C<1>, libev will try to detect the availability of the |
2314 | If defined to be C<1>, libev will try to detect the availability of the |
1972 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2315 | monotonic clock option at both compiletime and runtime. Otherwise no use |
1973 | of the monotonic clock option will be attempted. If you enable this, you |
2316 | of the monotonic clock option will be attempted. If you enable this, you |
1974 | usually have to link against librt or something similar. Enabling it when |
2317 | usually have to link against librt or something similar. Enabling it when |
1975 | the functionality isn't available is safe, though, althoguh you have |
2318 | the functionality isn't available is safe, though, although you have |
1976 | to make sure you link against any libraries where the C<clock_gettime> |
2319 | to make sure you link against any libraries where the C<clock_gettime> |
1977 | function is hiding in (often F<-lrt>). |
2320 | function is hiding in (often F<-lrt>). |
1978 | |
2321 | |
1979 | =item EV_USE_REALTIME |
2322 | =item EV_USE_REALTIME |
1980 | |
2323 | |
1981 | If defined to be C<1>, libev will try to detect the availability of the |
2324 | If defined to be C<1>, libev will try to detect the availability of the |
1982 | realtime clock option at compiletime (and assume its availability at |
2325 | realtime clock option at compiletime (and assume its availability at |
1983 | runtime if successful). Otherwise no use of the realtime clock option will |
2326 | runtime if successful). Otherwise no use of the realtime clock option will |
1984 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
2327 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
1985 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See tzhe note about libraries |
2328 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See the |
1986 | in the description of C<EV_USE_MONOTONIC>, though. |
2329 | note about libraries in the description of C<EV_USE_MONOTONIC>, though. |
|
|
2330 | |
|
|
2331 | =item EV_USE_NANOSLEEP |
|
|
2332 | |
|
|
2333 | If defined to be C<1>, libev will assume that C<nanosleep ()> is available |
|
|
2334 | and will use it for delays. Otherwise it will use C<select ()>. |
1987 | |
2335 | |
1988 | =item EV_USE_SELECT |
2336 | =item EV_USE_SELECT |
1989 | |
2337 | |
1990 | If undefined or defined to be C<1>, libev will compile in support for the |
2338 | If undefined or defined to be C<1>, libev will compile in support for the |
1991 | C<select>(2) backend. No attempt at autodetection will be done: if no |
2339 | C<select>(2) backend. No attempt at autodetection will be done: if no |
… | |
… | |
2084 | will have the C<struct ev_loop *> as first argument, and you can create |
2432 | will have the C<struct ev_loop *> as first argument, and you can create |
2085 | additional independent event loops. Otherwise there will be no support |
2433 | additional independent event loops. Otherwise there will be no support |
2086 | for multiple event loops and there is no first event loop pointer |
2434 | for multiple event loops and there is no first event loop pointer |
2087 | argument. Instead, all functions act on the single default loop. |
2435 | argument. Instead, all functions act on the single default loop. |
2088 | |
2436 | |
|
|
2437 | =item EV_MINPRI |
|
|
2438 | |
|
|
2439 | =item EV_MAXPRI |
|
|
2440 | |
|
|
2441 | The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to |
|
|
2442 | C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can |
|
|
2443 | provide for more priorities by overriding those symbols (usually defined |
|
|
2444 | to be C<-2> and C<2>, respectively). |
|
|
2445 | |
|
|
2446 | When doing priority-based operations, libev usually has to linearly search |
|
|
2447 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2448 | and time, so using the defaults of five priorities (-2 .. +2) is usually |
|
|
2449 | fine. |
|
|
2450 | |
|
|
2451 | If your embedding app does not need any priorities, defining these both to |
|
|
2452 | C<0> will save some memory and cpu. |
|
|
2453 | |
2089 | =item EV_PERIODIC_ENABLE |
2454 | =item EV_PERIODIC_ENABLE |
2090 | |
2455 | |
2091 | If undefined or defined to be C<1>, then periodic timers are supported. If |
2456 | If undefined or defined to be C<1>, then periodic timers are supported. If |
|
|
2457 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2458 | code. |
|
|
2459 | |
|
|
2460 | =item EV_IDLE_ENABLE |
|
|
2461 | |
|
|
2462 | If undefined or defined to be C<1>, then idle watchers are supported. If |
2092 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2463 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2093 | code. |
2464 | code. |
2094 | |
2465 | |
2095 | =item EV_EMBED_ENABLE |
2466 | =item EV_EMBED_ENABLE |
2096 | |
2467 | |
… | |
… | |
2147 | |
2518 | |
2148 | =item ev_set_cb (ev, cb) |
2519 | =item ev_set_cb (ev, cb) |
2149 | |
2520 | |
2150 | Can be used to change the callback member declaration in each watcher, |
2521 | Can be used to change the callback member declaration in each watcher, |
2151 | and the way callbacks are invoked and set. Must expand to a struct member |
2522 | and the way callbacks are invoked and set. Must expand to a struct member |
2152 | definition and a statement, respectively. See the F<ev.v> header file for |
2523 | definition and a statement, respectively. See the F<ev.h> header file for |
2153 | their default definitions. One possible use for overriding these is to |
2524 | their default definitions. One possible use for overriding these is to |
2154 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
2525 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
2155 | method calls instead of plain function calls in C++. |
2526 | method calls instead of plain function calls in C++. |
|
|
2527 | |
|
|
2528 | =head2 EXPORTED API SYMBOLS |
|
|
2529 | |
|
|
2530 | If you need to re-export the API (e.g. via a dll) and you need a list of |
|
|
2531 | exported symbols, you can use the provided F<Symbol.*> files which list |
|
|
2532 | all public symbols, one per line: |
|
|
2533 | |
|
|
2534 | Symbols.ev for libev proper |
|
|
2535 | Symbols.event for the libevent emulation |
|
|
2536 | |
|
|
2537 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2538 | multiple versions of libev linked together (which is obviously bad in |
|
|
2539 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2540 | |
|
|
2541 | A sed command like this will create wrapper C<#define>'s that you need to |
|
|
2542 | include before including F<ev.h>: |
|
|
2543 | |
|
|
2544 | <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2545 | |
|
|
2546 | This would create a file F<wrap.h> which essentially looks like this: |
|
|
2547 | |
|
|
2548 | #define ev_backend myprefix_ev_backend |
|
|
2549 | #define ev_check_start myprefix_ev_check_start |
|
|
2550 | #define ev_check_stop myprefix_ev_check_stop |
|
|
2551 | ... |
2156 | |
2552 | |
2157 | =head2 EXAMPLES |
2553 | =head2 EXAMPLES |
2158 | |
2554 | |
2159 | For a real-world example of a program the includes libev |
2555 | For a real-world example of a program the includes libev |
2160 | verbatim, you can have a look at the EV perl module |
2556 | verbatim, you can have a look at the EV perl module |
… | |
… | |
2163 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2559 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2164 | will be compiled. It is pretty complex because it provides its own header |
2560 | will be compiled. It is pretty complex because it provides its own header |
2165 | file. |
2561 | file. |
2166 | |
2562 | |
2167 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2563 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2168 | that everybody includes and which overrides some autoconf choices: |
2564 | that everybody includes and which overrides some configure choices: |
2169 | |
2565 | |
|
|
2566 | #define EV_MINIMAL 1 |
2170 | #define EV_USE_POLL 0 |
2567 | #define EV_USE_POLL 0 |
2171 | #define EV_MULTIPLICITY 0 |
2568 | #define EV_MULTIPLICITY 0 |
2172 | #define EV_PERIODICS 0 |
2569 | #define EV_PERIODIC_ENABLE 0 |
|
|
2570 | #define EV_STAT_ENABLE 0 |
|
|
2571 | #define EV_FORK_ENABLE 0 |
2173 | #define EV_CONFIG_H <config.h> |
2572 | #define EV_CONFIG_H <config.h> |
|
|
2573 | #define EV_MINPRI 0 |
|
|
2574 | #define EV_MAXPRI 0 |
2174 | |
2575 | |
2175 | #include "ev++.h" |
2576 | #include "ev++.h" |
2176 | |
2577 | |
2177 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2578 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2178 | |
2579 | |
… | |
… | |
2184 | |
2585 | |
2185 | In this section the complexities of (many of) the algorithms used inside |
2586 | In this section the complexities of (many of) the algorithms used inside |
2186 | libev will be explained. For complexity discussions about backends see the |
2587 | libev will be explained. For complexity discussions about backends see the |
2187 | documentation for C<ev_default_init>. |
2588 | documentation for C<ev_default_init>. |
2188 | |
2589 | |
|
|
2590 | All of the following are about amortised time: If an array needs to be |
|
|
2591 | extended, libev needs to realloc and move the whole array, but this |
|
|
2592 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2593 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2594 | it is much faster and asymptotically approaches constant time. |
|
|
2595 | |
2189 | =over 4 |
2596 | =over 4 |
2190 | |
2597 | |
2191 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2598 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2192 | |
2599 | |
|
|
2600 | This means that, when you have a watcher that triggers in one hour and |
|
|
2601 | there are 100 watchers that would trigger before that then inserting will |
|
|
2602 | have to skip those 100 watchers. |
|
|
2603 | |
2193 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2604 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2194 | |
2605 | |
|
|
2606 | That means that for changing a timer costs less than removing/adding them |
|
|
2607 | as only the relative motion in the event queue has to be paid for. |
|
|
2608 | |
2195 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2609 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2196 | |
2610 | |
|
|
2611 | These just add the watcher into an array or at the head of a list. |
2197 | =item Stopping check/prepare/idle watchers: O(1) |
2612 | =item Stopping check/prepare/idle watchers: O(1) |
2198 | |
2613 | |
2199 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2614 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
2200 | |
2615 | |
|
|
2616 | These watchers are stored in lists then need to be walked to find the |
|
|
2617 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2618 | have many watchers waiting for the same fd or signal). |
|
|
2619 | |
2201 | =item Finding the next timer per loop iteration: O(1) |
2620 | =item Finding the next timer per loop iteration: O(1) |
2202 | |
2621 | |
2203 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2622 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2204 | |
2623 | |
|
|
2624 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2625 | libev to recalculate its status (and possibly tell the kernel). |
|
|
2626 | |
2205 | =item Activating one watcher: O(1) |
2627 | =item Activating one watcher: O(1) |
2206 | |
2628 | |
|
|
2629 | =item Priority handling: O(number_of_priorities) |
|
|
2630 | |
|
|
2631 | Priorities are implemented by allocating some space for each |
|
|
2632 | priority. When doing priority-based operations, libev usually has to |
|
|
2633 | linearly search all the priorities. |
|
|
2634 | |
2207 | =back |
2635 | =back |
2208 | |
2636 | |
2209 | |
2637 | |
2210 | =head1 AUTHOR |
2638 | =head1 AUTHOR |
2211 | |
2639 | |