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2 | |
2 | |
3 | libev - a high performance full-featured event loop written in C |
3 | libev - a high performance full-featured event loop written in C |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | #include <ev.h> |
7 | #include <ev.h> |
8 | |
8 | |
9 | =head2 EXAMPLE PROGRAM |
9 | =head2 EXAMPLE PROGRAM |
10 | |
10 | |
11 | // a single header file is required |
11 | // a single header file is required |
12 | #include <ev.h> |
12 | #include <ev.h> |
13 | |
13 | |
14 | // every watcher type has its own typedef'd struct |
14 | // every watcher type has its own typedef'd struct |
15 | // with the name ev_<type> |
15 | // with the name ev_<type> |
16 | ev_io stdin_watcher; |
16 | ev_io stdin_watcher; |
17 | ev_timer timeout_watcher; |
17 | ev_timer timeout_watcher; |
18 | |
18 | |
19 | // all watcher callbacks have a similar signature |
19 | // all watcher callbacks have a similar signature |
20 | // this callback is called when data is readable on stdin |
20 | // this callback is called when data is readable on stdin |
21 | static void |
21 | static void |
22 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
22 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
23 | { |
23 | { |
24 | puts ("stdin ready"); |
24 | puts ("stdin ready"); |
25 | // for one-shot events, one must manually stop the watcher |
25 | // for one-shot events, one must manually stop the watcher |
26 | // with its corresponding stop function. |
26 | // with its corresponding stop function. |
27 | ev_io_stop (EV_A_ w); |
27 | ev_io_stop (EV_A_ w); |
28 | |
28 | |
29 | // this causes all nested ev_loop's to stop iterating |
29 | // this causes all nested ev_loop's to stop iterating |
30 | ev_unloop (EV_A_ EVUNLOOP_ALL); |
30 | ev_unloop (EV_A_ EVUNLOOP_ALL); |
31 | } |
31 | } |
32 | |
32 | |
33 | // another callback, this time for a time-out |
33 | // another callback, this time for a time-out |
34 | static void |
34 | static void |
35 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
35 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
36 | { |
36 | { |
37 | puts ("timeout"); |
37 | puts ("timeout"); |
38 | // this causes the innermost ev_loop to stop iterating |
38 | // this causes the innermost ev_loop to stop iterating |
39 | ev_unloop (EV_A_ EVUNLOOP_ONE); |
39 | ev_unloop (EV_A_ EVUNLOOP_ONE); |
40 | } |
40 | } |
41 | |
41 | |
42 | int |
42 | int |
43 | main (void) |
43 | main (void) |
44 | { |
44 | { |
45 | // use the default event loop unless you have special needs |
45 | // use the default event loop unless you have special needs |
46 | struct ev_loop *loop = ev_default_loop (0); |
46 | struct ev_loop *loop = ev_default_loop (0); |
47 | |
47 | |
48 | // initialise an io watcher, then start it |
48 | // initialise an io watcher, then start it |
49 | // this one will watch for stdin to become readable |
49 | // this one will watch for stdin to become readable |
50 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
50 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
51 | ev_io_start (loop, &stdin_watcher); |
51 | ev_io_start (loop, &stdin_watcher); |
52 | |
52 | |
53 | // initialise a timer watcher, then start it |
53 | // initialise a timer watcher, then start it |
54 | // simple non-repeating 5.5 second timeout |
54 | // simple non-repeating 5.5 second timeout |
55 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
55 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
56 | ev_timer_start (loop, &timeout_watcher); |
56 | ev_timer_start (loop, &timeout_watcher); |
57 | |
57 | |
58 | // now wait for events to arrive |
58 | // now wait for events to arrive |
59 | ev_loop (loop, 0); |
59 | ev_loop (loop, 0); |
60 | |
60 | |
61 | // unloop was called, so exit |
61 | // unloop was called, so exit |
62 | return 0; |
62 | return 0; |
63 | } |
63 | } |
64 | |
64 | |
65 | =head1 DESCRIPTION |
65 | =head1 DESCRIPTION |
66 | |
66 | |
67 | The newest version of this document is also available as an html-formatted |
67 | The newest version of this document is also available as an html-formatted |
68 | web page you might find easier to navigate when reading it for the first |
68 | web page you might find easier to navigate when reading it for the first |
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178 | not a problem. |
178 | not a problem. |
179 | |
179 | |
180 | Example: Make sure we haven't accidentally been linked against the wrong |
180 | Example: Make sure we haven't accidentally been linked against the wrong |
181 | version. |
181 | version. |
182 | |
182 | |
183 | assert (("libev version mismatch", |
183 | assert (("libev version mismatch", |
184 | ev_version_major () == EV_VERSION_MAJOR |
184 | ev_version_major () == EV_VERSION_MAJOR |
185 | && ev_version_minor () >= EV_VERSION_MINOR)); |
185 | && ev_version_minor () >= EV_VERSION_MINOR)); |
186 | |
186 | |
187 | =item unsigned int ev_supported_backends () |
187 | =item unsigned int ev_supported_backends () |
188 | |
188 | |
189 | Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*> |
189 | Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*> |
190 | value) compiled into this binary of libev (independent of their |
190 | value) compiled into this binary of libev (independent of their |
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192 | a description of the set values. |
192 | a description of the set values. |
193 | |
193 | |
194 | Example: make sure we have the epoll method, because yeah this is cool and |
194 | Example: make sure we have the epoll method, because yeah this is cool and |
195 | a must have and can we have a torrent of it please!!!11 |
195 | a must have and can we have a torrent of it please!!!11 |
196 | |
196 | |
197 | assert (("sorry, no epoll, no sex", |
197 | assert (("sorry, no epoll, no sex", |
198 | ev_supported_backends () & EVBACKEND_EPOLL)); |
198 | ev_supported_backends () & EVBACKEND_EPOLL)); |
199 | |
199 | |
200 | =item unsigned int ev_recommended_backends () |
200 | =item unsigned int ev_recommended_backends () |
201 | |
201 | |
202 | Return the set of all backends compiled into this binary of libev and also |
202 | Return the set of all backends compiled into this binary of libev and also |
203 | recommended for this platform. This set is often smaller than the one |
203 | recommended for this platform. This set is often smaller than the one |
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359 | writing a server, you should C<accept ()> in a loop to accept as many |
359 | writing a server, you should C<accept ()> in a loop to accept as many |
360 | connections as possible during one iteration. You might also want to have |
360 | connections as possible during one iteration. You might also want to have |
361 | a look at C<ev_set_io_collect_interval ()> to increase the amount of |
361 | a look at C<ev_set_io_collect_interval ()> to increase the amount of |
362 | readiness notifications you get per iteration. |
362 | readiness notifications you get per iteration. |
363 | |
363 | |
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364 | This backend maps C<EV_READ> to the C<readfds> set and C<EV_WRITE> to the |
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365 | C<writefds> set (and to work around Microsoft Windows bugs, also onto the |
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366 | C<exceptfds> set on that platform). |
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367 | |
364 | =item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows) |
368 | =item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows) |
365 | |
369 | |
366 | And this is your standard poll(2) backend. It's more complicated |
370 | And this is your standard poll(2) backend. It's more complicated |
367 | than select, but handles sparse fds better and has no artificial |
371 | than select, but handles sparse fds better and has no artificial |
368 | limit on the number of fds you can use (except it will slow down |
372 | limit on the number of fds you can use (except it will slow down |
369 | considerably with a lot of inactive fds). It scales similarly to select, |
373 | considerably with a lot of inactive fds). It scales similarly to select, |
370 | i.e. O(total_fds). See the entry for C<EVBACKEND_SELECT>, above, for |
374 | i.e. O(total_fds). See the entry for C<EVBACKEND_SELECT>, above, for |
371 | performance tips. |
375 | performance tips. |
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376 | |
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377 | This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and |
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378 | C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>. |
372 | |
379 | |
373 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
380 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
374 | |
381 | |
375 | For few fds, this backend is a bit little slower than poll and select, |
382 | For few fds, this backend is a bit little slower than poll and select, |
376 | but it scales phenomenally better. While poll and select usually scale |
383 | but it scales phenomenally better. While poll and select usually scale |
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395 | keep at least one watcher active per fd at all times. |
402 | keep at least one watcher active per fd at all times. |
396 | |
403 | |
397 | While nominally embeddable in other event loops, this feature is broken in |
404 | While nominally embeddable in other event loops, this feature is broken in |
398 | all kernel versions tested so far. |
405 | all kernel versions tested so far. |
399 | |
406 | |
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407 | This backend maps C<EV_READ> and C<EV_WRITE> in the same way as |
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408 | C<EVBACKEND_POLL>. |
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409 | |
400 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
410 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
401 | |
411 | |
402 | Kqueue deserves special mention, as at the time of this writing, it |
412 | Kqueue deserves special mention, as at the time of this writing, it |
403 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
413 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
404 | with anything but sockets and pipes, except on Darwin, where of course |
414 | with anything but sockets and pipes, except on Darwin, where of course |
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425 | almost everywhere, you should only use it when you have a lot of sockets |
435 | almost everywhere, you should only use it when you have a lot of sockets |
426 | (for which it usually works), by embedding it into another event loop |
436 | (for which it usually works), by embedding it into another event loop |
427 | (e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>) and using it only for |
437 | (e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>) and using it only for |
428 | sockets. |
438 | sockets. |
429 | |
439 | |
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440 | This backend maps C<EV_READ> into an C<EVFILT_READ> kevent with |
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441 | C<NOTE_EOF>, and C<EV_WRITE> into an C<EVFILT_WRITE> kevent with |
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442 | C<NOTE_EOF>. |
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443 | |
430 | =item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8) |
444 | =item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8) |
431 | |
445 | |
432 | This is not implemented yet (and might never be, unless you send me an |
446 | This is not implemented yet (and might never be, unless you send me an |
433 | implementation). According to reports, C</dev/poll> only supports sockets |
447 | implementation). According to reports, C</dev/poll> only supports sockets |
434 | and is not embeddable, which would limit the usefulness of this backend |
448 | and is not embeddable, which would limit the usefulness of this backend |
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450 | |
464 | |
451 | On the positive side, ignoring the spurious readiness notifications, this |
465 | On the positive side, ignoring the spurious readiness notifications, this |
452 | backend actually performed to specification in all tests and is fully |
466 | backend actually performed to specification in all tests and is fully |
453 | embeddable, which is a rare feat among the OS-specific backends. |
467 | embeddable, which is a rare feat among the OS-specific backends. |
454 | |
468 | |
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469 | This backend maps C<EV_READ> and C<EV_WRITE> in the same way as |
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470 | C<EVBACKEND_POLL>. |
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471 | |
455 | =item C<EVBACKEND_ALL> |
472 | =item C<EVBACKEND_ALL> |
456 | |
473 | |
457 | Try all backends (even potentially broken ones that wouldn't be tried |
474 | Try all backends (even potentially broken ones that wouldn't be tried |
458 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
475 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
459 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
476 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
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466 | backends will be tried (in the reverse order as listed here). If none are |
483 | backends will be tried (in the reverse order as listed here). If none are |
467 | specified, all backends in C<ev_recommended_backends ()> will be tried. |
484 | specified, all backends in C<ev_recommended_backends ()> will be tried. |
468 | |
485 | |
469 | The most typical usage is like this: |
486 | The most typical usage is like this: |
470 | |
487 | |
471 | if (!ev_default_loop (0)) |
488 | if (!ev_default_loop (0)) |
472 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
489 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
473 | |
490 | |
474 | Restrict libev to the select and poll backends, and do not allow |
491 | Restrict libev to the select and poll backends, and do not allow |
475 | environment settings to be taken into account: |
492 | environment settings to be taken into account: |
476 | |
493 | |
477 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
494 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
478 | |
495 | |
479 | Use whatever libev has to offer, but make sure that kqueue is used if |
496 | Use whatever libev has to offer, but make sure that kqueue is used if |
480 | available (warning, breaks stuff, best use only with your own private |
497 | available (warning, breaks stuff, best use only with your own private |
481 | event loop and only if you know the OS supports your types of fds): |
498 | event loop and only if you know the OS supports your types of fds): |
482 | |
499 | |
483 | ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
500 | ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
484 | |
501 | |
485 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
502 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
486 | |
503 | |
487 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
504 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
488 | always distinct from the default loop. Unlike the default loop, it cannot |
505 | always distinct from the default loop. Unlike the default loop, it cannot |
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493 | libev with threads is indeed to create one loop per thread, and using the |
510 | libev with threads is indeed to create one loop per thread, and using the |
494 | default loop in the "main" or "initial" thread. |
511 | default loop in the "main" or "initial" thread. |
495 | |
512 | |
496 | Example: Try to create a event loop that uses epoll and nothing else. |
513 | Example: Try to create a event loop that uses epoll and nothing else. |
497 | |
514 | |
498 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
515 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
499 | if (!epoller) |
516 | if (!epoller) |
500 | fatal ("no epoll found here, maybe it hides under your chair"); |
517 | fatal ("no epoll found here, maybe it hides under your chair"); |
501 | |
518 | |
502 | =item ev_default_destroy () |
519 | =item ev_default_destroy () |
503 | |
520 | |
504 | Destroys the default loop again (frees all memory and kernel state |
521 | Destroys the default loop again (frees all memory and kernel state |
505 | etc.). None of the active event watchers will be stopped in the normal |
522 | etc.). None of the active event watchers will be stopped in the normal |
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573 | received events and started processing them. This timestamp does not |
590 | received events and started processing them. This timestamp does not |
574 | change as long as callbacks are being processed, and this is also the base |
591 | change as long as callbacks are being processed, and this is also the base |
575 | time used for relative timers. You can treat it as the timestamp of the |
592 | time used for relative timers. You can treat it as the timestamp of the |
576 | event occurring (or more correctly, libev finding out about it). |
593 | event occurring (or more correctly, libev finding out about it). |
577 | |
594 | |
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595 | =item ev_now_update (loop) |
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596 | |
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597 | Establishes the current time by querying the kernel, updating the time |
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598 | returned by C<ev_now ()> in the progress. This is a costly operation and |
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599 | is usually done automatically within C<ev_loop ()>. |
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600 | |
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601 | This function is rarely useful, but when some event callback runs for a |
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602 | very long time without entering the event loop, updating libev's idea of |
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603 | the current time is a good idea. |
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604 | |
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605 | See also "The special problem of time updates" in the C<ev_timer> section. |
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606 | |
578 | =item ev_loop (loop, int flags) |
607 | =item ev_loop (loop, int flags) |
579 | |
608 | |
580 | Finally, this is it, the event handler. This function usually is called |
609 | Finally, this is it, the event handler. This function usually is called |
581 | after you initialised all your watchers and you want to start handling |
610 | after you initialised all your watchers and you want to start handling |
582 | events. |
611 | events. |
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604 | |
633 | |
605 | Here are the gory details of what C<ev_loop> does: |
634 | Here are the gory details of what C<ev_loop> does: |
606 | |
635 | |
607 | - Before the first iteration, call any pending watchers. |
636 | - Before the first iteration, call any pending watchers. |
608 | * If EVFLAG_FORKCHECK was used, check for a fork. |
637 | * If EVFLAG_FORKCHECK was used, check for a fork. |
609 | - If a fork was detected, queue and call all fork watchers. |
638 | - If a fork was detected (by any means), queue and call all fork watchers. |
610 | - Queue and call all prepare watchers. |
639 | - Queue and call all prepare watchers. |
611 | - If we have been forked, recreate the kernel state. |
640 | - If we have been forked, detach and recreate the kernel state |
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641 | as to not disturb the other process. |
612 | - Update the kernel state with all outstanding changes. |
642 | - Update the kernel state with all outstanding changes. |
613 | - Update the "event loop time". |
643 | - Update the "event loop time" (ev_now ()). |
614 | - Calculate for how long to sleep or block, if at all |
644 | - Calculate for how long to sleep or block, if at all |
615 | (active idle watchers, EVLOOP_NONBLOCK or not having |
645 | (active idle watchers, EVLOOP_NONBLOCK or not having |
616 | any active watchers at all will result in not sleeping). |
646 | any active watchers at all will result in not sleeping). |
617 | - Sleep if the I/O and timer collect interval say so. |
647 | - Sleep if the I/O and timer collect interval say so. |
618 | - Block the process, waiting for any events. |
648 | - Block the process, waiting for any events. |
619 | - Queue all outstanding I/O (fd) events. |
649 | - Queue all outstanding I/O (fd) events. |
620 | - Update the "event loop time" and do time jump handling. |
650 | - Update the "event loop time" (ev_now ()), and do time jump adjustments. |
621 | - Queue all outstanding timers. |
651 | - Queue all outstanding timers. |
622 | - Queue all outstanding periodics. |
652 | - Queue all outstanding periodics. |
623 | - If no events are pending now, queue all idle watchers. |
653 | - Unless any events are pending now, queue all idle watchers. |
624 | - Queue all check watchers. |
654 | - Queue all check watchers. |
625 | - Call all queued watchers in reverse order (i.e. check watchers first). |
655 | - Call all queued watchers in reverse order (i.e. check watchers first). |
626 | Signals and child watchers are implemented as I/O watchers, and will |
656 | Signals and child watchers are implemented as I/O watchers, and will |
627 | be handled here by queueing them when their watcher gets executed. |
657 | be handled here by queueing them when their watcher gets executed. |
628 | - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
658 | - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
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633 | anymore. |
663 | anymore. |
634 | |
664 | |
635 | ... queue jobs here, make sure they register event watchers as long |
665 | ... queue jobs here, make sure they register event watchers as long |
636 | ... as they still have work to do (even an idle watcher will do..) |
666 | ... as they still have work to do (even an idle watcher will do..) |
637 | ev_loop (my_loop, 0); |
667 | ev_loop (my_loop, 0); |
638 | ... jobs done. yeah! |
668 | ... jobs done or somebody called unloop. yeah! |
639 | |
669 | |
640 | =item ev_unloop (loop, how) |
670 | =item ev_unloop (loop, how) |
641 | |
671 | |
642 | Can be used to make a call to C<ev_loop> return early (but only after it |
672 | Can be used to make a call to C<ev_loop> return early (but only after it |
643 | has processed all outstanding events). The C<how> argument must be either |
673 | has processed all outstanding events). The C<how> argument must be either |
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664 | respectively). |
694 | respectively). |
665 | |
695 | |
666 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
696 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
667 | running when nothing else is active. |
697 | running when nothing else is active. |
668 | |
698 | |
669 | struct ev_signal exitsig; |
699 | struct ev_signal exitsig; |
670 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
700 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
671 | ev_signal_start (loop, &exitsig); |
701 | ev_signal_start (loop, &exitsig); |
672 | evf_unref (loop); |
702 | evf_unref (loop); |
673 | |
703 | |
674 | Example: For some weird reason, unregister the above signal handler again. |
704 | Example: For some weird reason, unregister the above signal handler again. |
675 | |
705 | |
676 | ev_ref (loop); |
706 | ev_ref (loop); |
677 | ev_signal_stop (loop, &exitsig); |
707 | ev_signal_stop (loop, &exitsig); |
678 | |
708 | |
679 | =item ev_set_io_collect_interval (loop, ev_tstamp interval) |
709 | =item ev_set_io_collect_interval (loop, ev_tstamp interval) |
680 | |
710 | |
681 | =item ev_set_timeout_collect_interval (loop, ev_tstamp interval) |
711 | =item ev_set_timeout_collect_interval (loop, ev_tstamp interval) |
682 | |
712 | |
683 | These advanced functions influence the time that libev will spend waiting |
713 | These advanced functions influence the time that libev will spend waiting |
684 | for events. Both are by default C<0>, meaning that libev will try to |
714 | for events. Both time intervals are by default C<0>, meaning that libev |
685 | invoke timer/periodic callbacks and I/O callbacks with minimum latency. |
715 | will try to invoke timer/periodic callbacks and I/O callbacks with minimum |
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716 | latency. |
686 | |
717 | |
687 | Setting these to a higher value (the C<interval> I<must> be >= C<0>) |
718 | Setting these to a higher value (the C<interval> I<must> be >= C<0>) |
688 | allows libev to delay invocation of I/O and timer/periodic callbacks to |
719 | allows libev to delay invocation of I/O and timer/periodic callbacks |
689 | increase efficiency of loop iterations. |
720 | to increase efficiency of loop iterations (or to increase power-saving |
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721 | opportunities). |
690 | |
722 | |
691 | The background is that sometimes your program runs just fast enough to |
723 | The background is that sometimes your program runs just fast enough to |
692 | handle one (or very few) event(s) per loop iteration. While this makes |
724 | handle one (or very few) event(s) per loop iteration. While this makes |
693 | the program responsive, it also wastes a lot of CPU time to poll for new |
725 | the program responsive, it also wastes a lot of CPU time to poll for new |
694 | events, especially with backends like C<select ()> which have a high |
726 | events, especially with backends like C<select ()> which have a high |
… | |
… | |
710 | interval to a value near C<0.1> or so, which is often enough for |
742 | interval to a value near C<0.1> or so, which is often enough for |
711 | interactive servers (of course not for games), likewise for timeouts. It |
743 | interactive servers (of course not for games), likewise for timeouts. It |
712 | usually doesn't make much sense to set it to a lower value than C<0.01>, |
744 | usually doesn't make much sense to set it to a lower value than C<0.01>, |
713 | as this approaches the timing granularity of most systems. |
745 | as this approaches the timing granularity of most systems. |
714 | |
746 | |
|
|
747 | Setting the I<timeout collect interval> can improve the opportunity for |
|
|
748 | saving power, as the program will "bundle" timer callback invocations that |
|
|
749 | are "near" in time together, by delaying some, thus reducing the number of |
|
|
750 | times the process sleeps and wakes up again. Another useful technique to |
|
|
751 | reduce iterations/wake-ups is to use C<ev_periodic> watchers and make sure |
|
|
752 | they fire on, say, one-second boundaries only. |
|
|
753 | |
715 | =item ev_loop_verify (loop) |
754 | =item ev_loop_verify (loop) |
716 | |
755 | |
717 | This function only does something when C<EV_VERIFY> support has been |
756 | This function only does something when C<EV_VERIFY> support has been |
718 | compiled in. It tries to go through all internal structures and checks |
757 | compiled in. It tries to go through all internal structures and checks |
719 | them for validity. If anything is found to be inconsistent, it will print |
758 | them for validity. If anything is found to be inconsistent, it will print |
… | |
… | |
730 | |
769 | |
731 | A watcher is a structure that you create and register to record your |
770 | A watcher is a structure that you create and register to record your |
732 | interest in some event. For instance, if you want to wait for STDIN to |
771 | interest in some event. For instance, if you want to wait for STDIN to |
733 | become readable, you would create an C<ev_io> watcher for that: |
772 | become readable, you would create an C<ev_io> watcher for that: |
734 | |
773 | |
735 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
774 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
736 | { |
775 | { |
737 | ev_io_stop (w); |
776 | ev_io_stop (w); |
738 | ev_unloop (loop, EVUNLOOP_ALL); |
777 | ev_unloop (loop, EVUNLOOP_ALL); |
739 | } |
778 | } |
740 | |
779 | |
741 | struct ev_loop *loop = ev_default_loop (0); |
780 | struct ev_loop *loop = ev_default_loop (0); |
742 | struct ev_io stdin_watcher; |
781 | struct ev_io stdin_watcher; |
743 | ev_init (&stdin_watcher, my_cb); |
782 | ev_init (&stdin_watcher, my_cb); |
744 | ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
783 | ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
745 | ev_io_start (loop, &stdin_watcher); |
784 | ev_io_start (loop, &stdin_watcher); |
746 | ev_loop (loop, 0); |
785 | ev_loop (loop, 0); |
747 | |
786 | |
748 | As you can see, you are responsible for allocating the memory for your |
787 | As you can see, you are responsible for allocating the memory for your |
749 | watcher structures (and it is usually a bad idea to do this on the stack, |
788 | watcher structures (and it is usually a bad idea to do this on the stack, |
750 | although this can sometimes be quite valid). |
789 | although this can sometimes be quite valid). |
751 | |
790 | |
… | |
… | |
978 | to associate arbitrary data with your watcher. If you need more data and |
1017 | to associate arbitrary data with your watcher. If you need more data and |
979 | don't want to allocate memory and store a pointer to it in that data |
1018 | don't want to allocate memory and store a pointer to it in that data |
980 | member, you can also "subclass" the watcher type and provide your own |
1019 | member, you can also "subclass" the watcher type and provide your own |
981 | data: |
1020 | data: |
982 | |
1021 | |
983 | struct my_io |
1022 | struct my_io |
984 | { |
1023 | { |
985 | struct ev_io io; |
1024 | struct ev_io io; |
986 | int otherfd; |
1025 | int otherfd; |
987 | void *somedata; |
1026 | void *somedata; |
988 | struct whatever *mostinteresting; |
1027 | struct whatever *mostinteresting; |
989 | } |
1028 | }; |
|
|
1029 | |
|
|
1030 | ... |
|
|
1031 | struct my_io w; |
|
|
1032 | ev_io_init (&w.io, my_cb, fd, EV_READ); |
990 | |
1033 | |
991 | And since your callback will be called with a pointer to the watcher, you |
1034 | And since your callback will be called with a pointer to the watcher, you |
992 | can cast it back to your own type: |
1035 | can cast it back to your own type: |
993 | |
1036 | |
994 | static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents) |
1037 | static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents) |
995 | { |
1038 | { |
996 | struct my_io *w = (struct my_io *)w_; |
1039 | struct my_io *w = (struct my_io *)w_; |
997 | ... |
1040 | ... |
998 | } |
1041 | } |
999 | |
1042 | |
1000 | More interesting and less C-conformant ways of casting your callback type |
1043 | More interesting and less C-conformant ways of casting your callback type |
1001 | instead have been omitted. |
1044 | instead have been omitted. |
1002 | |
1045 | |
1003 | Another common scenario is having some data structure with multiple |
1046 | Another common scenario is to use some data structure with multiple |
1004 | watchers: |
1047 | embedded watchers: |
1005 | |
1048 | |
1006 | struct my_biggy |
1049 | struct my_biggy |
1007 | { |
1050 | { |
1008 | int some_data; |
1051 | int some_data; |
1009 | ev_timer t1; |
1052 | ev_timer t1; |
1010 | ev_timer t2; |
1053 | ev_timer t2; |
1011 | } |
1054 | } |
1012 | |
1055 | |
1013 | In this case getting the pointer to C<my_biggy> is a bit more complicated, |
1056 | In this case getting the pointer to C<my_biggy> is a bit more |
1014 | you need to use C<offsetof>: |
1057 | complicated: Either you store the address of your C<my_biggy> struct |
|
|
1058 | in the C<data> member of the watcher, or you need to use some pointer |
|
|
1059 | arithmetic using C<offsetof> inside your watchers: |
1015 | |
1060 | |
1016 | #include <stddef.h> |
1061 | #include <stddef.h> |
1017 | |
1062 | |
1018 | static void |
1063 | static void |
1019 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
1064 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
1020 | { |
1065 | { |
1021 | struct my_biggy big = (struct my_biggy * |
1066 | struct my_biggy big = (struct my_biggy * |
1022 | (((char *)w) - offsetof (struct my_biggy, t1)); |
1067 | (((char *)w) - offsetof (struct my_biggy, t1)); |
1023 | } |
1068 | } |
1024 | |
1069 | |
1025 | static void |
1070 | static void |
1026 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
1071 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
1027 | { |
1072 | { |
1028 | struct my_biggy big = (struct my_biggy * |
1073 | struct my_biggy big = (struct my_biggy * |
1029 | (((char *)w) - offsetof (struct my_biggy, t2)); |
1074 | (((char *)w) - offsetof (struct my_biggy, t2)); |
1030 | } |
1075 | } |
1031 | |
1076 | |
1032 | |
1077 | |
1033 | =head1 WATCHER TYPES |
1078 | =head1 WATCHER TYPES |
1034 | |
1079 | |
1035 | This section describes each watcher in detail, but will not repeat |
1080 | This section describes each watcher in detail, but will not repeat |
… | |
… | |
1124 | C<EVBACKEND_POLL>. |
1169 | C<EVBACKEND_POLL>. |
1125 | |
1170 | |
1126 | =head3 The special problem of SIGPIPE |
1171 | =head3 The special problem of SIGPIPE |
1127 | |
1172 | |
1128 | While not really specific to libev, it is easy to forget about SIGPIPE: |
1173 | While not really specific to libev, it is easy to forget about SIGPIPE: |
1129 | when reading from a pipe whose other end has been closed, your program |
1174 | when writing to a pipe whose other end has been closed, your program gets |
1130 | gets send a SIGPIPE, which, by default, aborts your program. For most |
1175 | send a SIGPIPE, which, by default, aborts your program. For most programs |
1131 | programs this is sensible behaviour, for daemons, this is usually |
1176 | this is sensible behaviour, for daemons, this is usually undesirable. |
1132 | undesirable. |
|
|
1133 | |
1177 | |
1134 | So when you encounter spurious, unexplained daemon exits, make sure you |
1178 | So when you encounter spurious, unexplained daemon exits, make sure you |
1135 | ignore SIGPIPE (and maybe make sure you log the exit status of your daemon |
1179 | ignore SIGPIPE (and maybe make sure you log the exit status of your daemon |
1136 | somewhere, as that would have given you a big clue). |
1180 | somewhere, as that would have given you a big clue). |
1137 | |
1181 | |
… | |
… | |
1162 | |
1206 | |
1163 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
1207 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
1164 | readable, but only once. Since it is likely line-buffered, you could |
1208 | readable, but only once. Since it is likely line-buffered, you could |
1165 | attempt to read a whole line in the callback. |
1209 | attempt to read a whole line in the callback. |
1166 | |
1210 | |
1167 | static void |
1211 | static void |
1168 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1212 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1169 | { |
1213 | { |
1170 | ev_io_stop (loop, w); |
1214 | ev_io_stop (loop, w); |
1171 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
1215 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
1172 | } |
1216 | } |
1173 | |
1217 | |
1174 | ... |
1218 | ... |
1175 | struct ev_loop *loop = ev_default_init (0); |
1219 | struct ev_loop *loop = ev_default_init (0); |
1176 | struct ev_io stdin_readable; |
1220 | struct ev_io stdin_readable; |
1177 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1221 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1178 | ev_io_start (loop, &stdin_readable); |
1222 | ev_io_start (loop, &stdin_readable); |
1179 | ev_loop (loop, 0); |
1223 | ev_loop (loop, 0); |
1180 | |
1224 | |
1181 | |
1225 | |
1182 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
1226 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
1183 | |
1227 | |
1184 | Timer watchers are simple relative timers that generate an event after a |
1228 | Timer watchers are simple relative timers that generate an event after a |
… | |
… | |
1188 | times out after an hour and you reset your system clock to January last |
1232 | times out after an hour and you reset your system clock to January last |
1189 | year, it will still time out after (roughly) and hour. "Roughly" because |
1233 | year, it will still time out after (roughly) and hour. "Roughly" because |
1190 | detecting time jumps is hard, and some inaccuracies are unavoidable (the |
1234 | detecting time jumps is hard, and some inaccuracies are unavoidable (the |
1191 | monotonic clock option helps a lot here). |
1235 | monotonic clock option helps a lot here). |
1192 | |
1236 | |
|
|
1237 | The callback is guaranteed to be invoked only after its timeout has passed, |
|
|
1238 | but if multiple timers become ready during the same loop iteration then |
|
|
1239 | order of execution is undefined. |
|
|
1240 | |
|
|
1241 | =head3 The special problem of time updates |
|
|
1242 | |
|
|
1243 | Establishing the current time is a costly operation (it usually takes at |
|
|
1244 | least two system calls): EV therefore updates its idea of the current |
|
|
1245 | time only before and after C<ev_loop> polls for new events, which causes |
|
|
1246 | a growing difference between C<ev_now ()> and C<ev_time ()> when handling |
|
|
1247 | lots of events. |
|
|
1248 | |
1193 | The relative timeouts are calculated relative to the C<ev_now ()> |
1249 | The relative timeouts are calculated relative to the C<ev_now ()> |
1194 | time. This is usually the right thing as this timestamp refers to the time |
1250 | time. This is usually the right thing as this timestamp refers to the time |
1195 | of the event triggering whatever timeout you are modifying/starting. If |
1251 | of the event triggering whatever timeout you are modifying/starting. If |
1196 | you suspect event processing to be delayed and you I<need> to base the timeout |
1252 | you suspect event processing to be delayed and you I<need> to base the |
1197 | on the current time, use something like this to adjust for this: |
1253 | timeout on the current time, use something like this to adjust for this: |
1198 | |
1254 | |
1199 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
1255 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
1200 | |
1256 | |
1201 | The callback is guaranteed to be invoked only after its timeout has passed, |
1257 | If the event loop is suspended for a long time, you can also force an |
1202 | but if multiple timers become ready during the same loop iteration then |
1258 | update of the time returned by C<ev_now ()> by calling C<ev_now_update |
1203 | order of execution is undefined. |
1259 | ()>. |
1204 | |
1260 | |
1205 | =head3 Watcher-Specific Functions and Data Members |
1261 | =head3 Watcher-Specific Functions and Data Members |
1206 | |
1262 | |
1207 | =over 4 |
1263 | =over 4 |
1208 | |
1264 | |
… | |
… | |
1269 | |
1325 | |
1270 | =head3 Examples |
1326 | =head3 Examples |
1271 | |
1327 | |
1272 | Example: Create a timer that fires after 60 seconds. |
1328 | Example: Create a timer that fires after 60 seconds. |
1273 | |
1329 | |
1274 | static void |
1330 | static void |
1275 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1331 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1276 | { |
1332 | { |
1277 | .. one minute over, w is actually stopped right here |
1333 | .. one minute over, w is actually stopped right here |
1278 | } |
1334 | } |
1279 | |
1335 | |
1280 | struct ev_timer mytimer; |
1336 | struct ev_timer mytimer; |
1281 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1337 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1282 | ev_timer_start (loop, &mytimer); |
1338 | ev_timer_start (loop, &mytimer); |
1283 | |
1339 | |
1284 | Example: Create a timeout timer that times out after 10 seconds of |
1340 | Example: Create a timeout timer that times out after 10 seconds of |
1285 | inactivity. |
1341 | inactivity. |
1286 | |
1342 | |
1287 | static void |
1343 | static void |
1288 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1344 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1289 | { |
1345 | { |
1290 | .. ten seconds without any activity |
1346 | .. ten seconds without any activity |
1291 | } |
1347 | } |
1292 | |
1348 | |
1293 | struct ev_timer mytimer; |
1349 | struct ev_timer mytimer; |
1294 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1350 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1295 | ev_timer_again (&mytimer); /* start timer */ |
1351 | ev_timer_again (&mytimer); /* start timer */ |
1296 | ev_loop (loop, 0); |
1352 | ev_loop (loop, 0); |
1297 | |
1353 | |
1298 | // and in some piece of code that gets executed on any "activity": |
1354 | // and in some piece of code that gets executed on any "activity": |
1299 | // reset the timeout to start ticking again at 10 seconds |
1355 | // reset the timeout to start ticking again at 10 seconds |
1300 | ev_timer_again (&mytimer); |
1356 | ev_timer_again (&mytimer); |
1301 | |
1357 | |
1302 | |
1358 | |
1303 | =head2 C<ev_periodic> - to cron or not to cron? |
1359 | =head2 C<ev_periodic> - to cron or not to cron? |
1304 | |
1360 | |
1305 | Periodic watchers are also timers of a kind, but they are very versatile |
1361 | Periodic watchers are also timers of a kind, but they are very versatile |
… | |
… | |
1448 | |
1504 | |
1449 | Example: Call a callback every hour, or, more precisely, whenever the |
1505 | Example: Call a callback every hour, or, more precisely, whenever the |
1450 | system clock is divisible by 3600. The callback invocation times have |
1506 | system clock is divisible by 3600. The callback invocation times have |
1451 | potentially a lot of jitter, but good long-term stability. |
1507 | potentially a lot of jitter, but good long-term stability. |
1452 | |
1508 | |
1453 | static void |
1509 | static void |
1454 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1510 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1455 | { |
1511 | { |
1456 | ... its now a full hour (UTC, or TAI or whatever your clock follows) |
1512 | ... its now a full hour (UTC, or TAI or whatever your clock follows) |
1457 | } |
1513 | } |
1458 | |
1514 | |
1459 | struct ev_periodic hourly_tick; |
1515 | struct ev_periodic hourly_tick; |
1460 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1516 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1461 | ev_periodic_start (loop, &hourly_tick); |
1517 | ev_periodic_start (loop, &hourly_tick); |
1462 | |
1518 | |
1463 | Example: The same as above, but use a reschedule callback to do it: |
1519 | Example: The same as above, but use a reschedule callback to do it: |
1464 | |
1520 | |
1465 | #include <math.h> |
1521 | #include <math.h> |
1466 | |
1522 | |
1467 | static ev_tstamp |
1523 | static ev_tstamp |
1468 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1524 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1469 | { |
1525 | { |
1470 | return fmod (now, 3600.) + 3600.; |
1526 | return fmod (now, 3600.) + 3600.; |
1471 | } |
1527 | } |
1472 | |
1528 | |
1473 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1529 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1474 | |
1530 | |
1475 | Example: Call a callback every hour, starting now: |
1531 | Example: Call a callback every hour, starting now: |
1476 | |
1532 | |
1477 | struct ev_periodic hourly_tick; |
1533 | struct ev_periodic hourly_tick; |
1478 | ev_periodic_init (&hourly_tick, clock_cb, |
1534 | ev_periodic_init (&hourly_tick, clock_cb, |
1479 | fmod (ev_now (loop), 3600.), 3600., 0); |
1535 | fmod (ev_now (loop), 3600.), 3600., 0); |
1480 | ev_periodic_start (loop, &hourly_tick); |
1536 | ev_periodic_start (loop, &hourly_tick); |
1481 | |
1537 | |
1482 | |
1538 | |
1483 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
1539 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
1484 | |
1540 | |
1485 | Signal watchers will trigger an event when the process receives a specific |
1541 | Signal watchers will trigger an event when the process receives a specific |
… | |
… | |
1519 | |
1575 | |
1520 | =head3 Examples |
1576 | =head3 Examples |
1521 | |
1577 | |
1522 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1578 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1523 | |
1579 | |
1524 | static void |
1580 | static void |
1525 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1581 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1526 | { |
1582 | { |
1527 | ev_unloop (loop, EVUNLOOP_ALL); |
1583 | ev_unloop (loop, EVUNLOOP_ALL); |
1528 | } |
1584 | } |
1529 | |
1585 | |
1530 | struct ev_signal signal_watcher; |
1586 | struct ev_signal signal_watcher; |
1531 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1587 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1532 | ev_signal_start (loop, &sigint_cb); |
1588 | ev_signal_start (loop, &sigint_cb); |
1533 | |
1589 | |
1534 | |
1590 | |
1535 | =head2 C<ev_child> - watch out for process status changes |
1591 | =head2 C<ev_child> - watch out for process status changes |
1536 | |
1592 | |
1537 | Child watchers trigger when your process receives a SIGCHLD in response to |
1593 | Child watchers trigger when your process receives a SIGCHLD in response to |
… | |
… | |
1559 | handler, you can override it easily by installing your own handler for |
1615 | handler, you can override it easily by installing your own handler for |
1560 | C<SIGCHLD> after initialising the default loop, and making sure the |
1616 | C<SIGCHLD> after initialising the default loop, and making sure the |
1561 | default loop never gets destroyed. You are encouraged, however, to use an |
1617 | default loop never gets destroyed. You are encouraged, however, to use an |
1562 | event-based approach to child reaping and thus use libev's support for |
1618 | event-based approach to child reaping and thus use libev's support for |
1563 | that, so other libev users can use C<ev_child> watchers freely. |
1619 | that, so other libev users can use C<ev_child> watchers freely. |
|
|
1620 | |
|
|
1621 | =head3 Stopping the Child Watcher |
|
|
1622 | |
|
|
1623 | Currently, the child watcher never gets stopped, even when the |
|
|
1624 | child terminates, so normally one needs to stop the watcher in the |
|
|
1625 | callback. Future versions of libev might stop the watcher automatically |
|
|
1626 | when a child exit is detected. |
1564 | |
1627 | |
1565 | =head3 Watcher-Specific Functions and Data Members |
1628 | =head3 Watcher-Specific Functions and Data Members |
1566 | |
1629 | |
1567 | =over 4 |
1630 | =over 4 |
1568 | |
1631 | |
… | |
… | |
1597 | =head3 Examples |
1660 | =head3 Examples |
1598 | |
1661 | |
1599 | Example: C<fork()> a new process and install a child handler to wait for |
1662 | Example: C<fork()> a new process and install a child handler to wait for |
1600 | its completion. |
1663 | its completion. |
1601 | |
1664 | |
1602 | ev_child cw; |
1665 | ev_child cw; |
1603 | |
1666 | |
1604 | static void |
1667 | static void |
1605 | child_cb (EV_P_ struct ev_child *w, int revents) |
1668 | child_cb (EV_P_ struct ev_child *w, int revents) |
1606 | { |
1669 | { |
1607 | ev_child_stop (EV_A_ w); |
1670 | ev_child_stop (EV_A_ w); |
1608 | printf ("process %d exited with status %x\n", w->rpid, w->rstatus); |
1671 | printf ("process %d exited with status %x\n", w->rpid, w->rstatus); |
1609 | } |
1672 | } |
1610 | |
1673 | |
1611 | pid_t pid = fork (); |
1674 | pid_t pid = fork (); |
1612 | |
1675 | |
1613 | if (pid < 0) |
1676 | if (pid < 0) |
1614 | // error |
1677 | // error |
1615 | else if (pid == 0) |
1678 | else if (pid == 0) |
1616 | { |
1679 | { |
1617 | // the forked child executes here |
1680 | // the forked child executes here |
1618 | exit (1); |
1681 | exit (1); |
1619 | } |
1682 | } |
1620 | else |
1683 | else |
1621 | { |
1684 | { |
1622 | ev_child_init (&cw, child_cb, pid, 0); |
1685 | ev_child_init (&cw, child_cb, pid, 0); |
1623 | ev_child_start (EV_DEFAULT_ &cw); |
1686 | ev_child_start (EV_DEFAULT_ &cw); |
1624 | } |
1687 | } |
1625 | |
1688 | |
1626 | |
1689 | |
1627 | =head2 C<ev_stat> - did the file attributes just change? |
1690 | =head2 C<ev_stat> - did the file attributes just change? |
1628 | |
1691 | |
1629 | This watches a file system path for attribute changes. That is, it calls |
1692 | This watches a file system path for attribute changes. That is, it calls |
… | |
… | |
1662 | will be no polling. |
1725 | will be no polling. |
1663 | |
1726 | |
1664 | =head3 ABI Issues (Largefile Support) |
1727 | =head3 ABI Issues (Largefile Support) |
1665 | |
1728 | |
1666 | Libev by default (unless the user overrides this) uses the default |
1729 | Libev by default (unless the user overrides this) uses the default |
1667 | compilation environment, which means that on systems with optionally |
1730 | compilation environment, which means that on systems with large file |
1668 | disabled large file support, you get the 32 bit version of the stat |
1731 | support disabled by default, you get the 32 bit version of the stat |
1669 | structure. When using the library from programs that change the ABI to |
1732 | structure. When using the library from programs that change the ABI to |
1670 | use 64 bit file offsets the programs will fail. In that case you have to |
1733 | use 64 bit file offsets the programs will fail. In that case you have to |
1671 | compile libev with the same flags to get binary compatibility. This is |
1734 | compile libev with the same flags to get binary compatibility. This is |
1672 | obviously the case with any flags that change the ABI, but the problem is |
1735 | obviously the case with any flags that change the ABI, but the problem is |
1673 | most noticeably with ev_stat and large file support. |
1736 | most noticeably disabled with ev_stat and large file support. |
|
|
1737 | |
|
|
1738 | The solution for this is to lobby your distribution maker to make large |
|
|
1739 | file interfaces available by default (as e.g. FreeBSD does) and not |
|
|
1740 | optional. Libev cannot simply switch on large file support because it has |
|
|
1741 | to exchange stat structures with application programs compiled using the |
|
|
1742 | default compilation environment. |
1674 | |
1743 | |
1675 | =head3 Inotify |
1744 | =head3 Inotify |
1676 | |
1745 | |
1677 | When C<inotify (7)> support has been compiled into libev (generally only |
1746 | When C<inotify (7)> support has been compiled into libev (generally only |
1678 | available on Linux) and present at runtime, it will be used to speed up |
1747 | available on Linux) and present at runtime, it will be used to speed up |
… | |
… | |
1767 | |
1836 | |
1768 | =head3 Examples |
1837 | =head3 Examples |
1769 | |
1838 | |
1770 | Example: Watch C</etc/passwd> for attribute changes. |
1839 | Example: Watch C</etc/passwd> for attribute changes. |
1771 | |
1840 | |
1772 | static void |
1841 | static void |
1773 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1842 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1774 | { |
1843 | { |
1775 | /* /etc/passwd changed in some way */ |
1844 | /* /etc/passwd changed in some way */ |
1776 | if (w->attr.st_nlink) |
1845 | if (w->attr.st_nlink) |
1777 | { |
1846 | { |
1778 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
1847 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
1779 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
1848 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
1780 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
1849 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
1781 | } |
1850 | } |
1782 | else |
1851 | else |
1783 | /* you shalt not abuse printf for puts */ |
1852 | /* you shalt not abuse printf for puts */ |
1784 | puts ("wow, /etc/passwd is not there, expect problems. " |
1853 | puts ("wow, /etc/passwd is not there, expect problems. " |
1785 | "if this is windows, they already arrived\n"); |
1854 | "if this is windows, they already arrived\n"); |
1786 | } |
1855 | } |
1787 | |
1856 | |
1788 | ... |
1857 | ... |
1789 | ev_stat passwd; |
1858 | ev_stat passwd; |
1790 | |
1859 | |
1791 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1860 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1792 | ev_stat_start (loop, &passwd); |
1861 | ev_stat_start (loop, &passwd); |
1793 | |
1862 | |
1794 | Example: Like above, but additionally use a one-second delay so we do not |
1863 | Example: Like above, but additionally use a one-second delay so we do not |
1795 | miss updates (however, frequent updates will delay processing, too, so |
1864 | miss updates (however, frequent updates will delay processing, too, so |
1796 | one might do the work both on C<ev_stat> callback invocation I<and> on |
1865 | one might do the work both on C<ev_stat> callback invocation I<and> on |
1797 | C<ev_timer> callback invocation). |
1866 | C<ev_timer> callback invocation). |
1798 | |
1867 | |
1799 | static ev_stat passwd; |
1868 | static ev_stat passwd; |
1800 | static ev_timer timer; |
1869 | static ev_timer timer; |
1801 | |
1870 | |
1802 | static void |
1871 | static void |
1803 | timer_cb (EV_P_ ev_timer *w, int revents) |
1872 | timer_cb (EV_P_ ev_timer *w, int revents) |
1804 | { |
1873 | { |
1805 | ev_timer_stop (EV_A_ w); |
1874 | ev_timer_stop (EV_A_ w); |
1806 | |
1875 | |
1807 | /* now it's one second after the most recent passwd change */ |
1876 | /* now it's one second after the most recent passwd change */ |
1808 | } |
1877 | } |
1809 | |
1878 | |
1810 | static void |
1879 | static void |
1811 | stat_cb (EV_P_ ev_stat *w, int revents) |
1880 | stat_cb (EV_P_ ev_stat *w, int revents) |
1812 | { |
1881 | { |
1813 | /* reset the one-second timer */ |
1882 | /* reset the one-second timer */ |
1814 | ev_timer_again (EV_A_ &timer); |
1883 | ev_timer_again (EV_A_ &timer); |
1815 | } |
1884 | } |
1816 | |
1885 | |
1817 | ... |
1886 | ... |
1818 | ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
1887 | ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
1819 | ev_stat_start (loop, &passwd); |
1888 | ev_stat_start (loop, &passwd); |
1820 | ev_timer_init (&timer, timer_cb, 0., 1.02); |
1889 | ev_timer_init (&timer, timer_cb, 0., 1.02); |
1821 | |
1890 | |
1822 | |
1891 | |
1823 | =head2 C<ev_idle> - when you've got nothing better to do... |
1892 | =head2 C<ev_idle> - when you've got nothing better to do... |
1824 | |
1893 | |
1825 | Idle watchers trigger events when no other events of the same or higher |
1894 | Idle watchers trigger events when no other events of the same or higher |
… | |
… | |
1856 | =head3 Examples |
1925 | =head3 Examples |
1857 | |
1926 | |
1858 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1927 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1859 | callback, free it. Also, use no error checking, as usual. |
1928 | callback, free it. Also, use no error checking, as usual. |
1860 | |
1929 | |
1861 | static void |
1930 | static void |
1862 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1931 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1863 | { |
1932 | { |
1864 | free (w); |
1933 | free (w); |
1865 | // now do something you wanted to do when the program has |
1934 | // now do something you wanted to do when the program has |
1866 | // no longer anything immediate to do. |
1935 | // no longer anything immediate to do. |
1867 | } |
1936 | } |
1868 | |
1937 | |
1869 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1938 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1870 | ev_idle_init (idle_watcher, idle_cb); |
1939 | ev_idle_init (idle_watcher, idle_cb); |
1871 | ev_idle_start (loop, idle_cb); |
1940 | ev_idle_start (loop, idle_cb); |
1872 | |
1941 | |
1873 | |
1942 | |
1874 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop! |
1943 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop! |
1875 | |
1944 | |
1876 | Prepare and check watchers are usually (but not always) used in tandem: |
1945 | Prepare and check watchers are usually (but not always) used in tandem: |
… | |
… | |
1948 | and in a check watcher, destroy them and call into libadns. What follows |
2017 | and in a check watcher, destroy them and call into libadns. What follows |
1949 | is pseudo-code only of course. This requires you to either use a low |
2018 | is pseudo-code only of course. This requires you to either use a low |
1950 | priority for the check watcher or use C<ev_clear_pending> explicitly, as |
2019 | priority for the check watcher or use C<ev_clear_pending> explicitly, as |
1951 | the callbacks for the IO/timeout watchers might not have been called yet. |
2020 | the callbacks for the IO/timeout watchers might not have been called yet. |
1952 | |
2021 | |
1953 | static ev_io iow [nfd]; |
2022 | static ev_io iow [nfd]; |
1954 | static ev_timer tw; |
2023 | static ev_timer tw; |
1955 | |
2024 | |
1956 | static void |
2025 | static void |
1957 | io_cb (ev_loop *loop, ev_io *w, int revents) |
2026 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1958 | { |
2027 | { |
1959 | } |
2028 | } |
1960 | |
2029 | |
1961 | // create io watchers for each fd and a timer before blocking |
2030 | // create io watchers for each fd and a timer before blocking |
1962 | static void |
2031 | static void |
1963 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
2032 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1964 | { |
2033 | { |
1965 | int timeout = 3600000; |
2034 | int timeout = 3600000; |
1966 | struct pollfd fds [nfd]; |
2035 | struct pollfd fds [nfd]; |
1967 | // actual code will need to loop here and realloc etc. |
2036 | // actual code will need to loop here and realloc etc. |
1968 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
2037 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1969 | |
2038 | |
1970 | /* the callback is illegal, but won't be called as we stop during check */ |
2039 | /* the callback is illegal, but won't be called as we stop during check */ |
1971 | ev_timer_init (&tw, 0, timeout * 1e-3); |
2040 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1972 | ev_timer_start (loop, &tw); |
2041 | ev_timer_start (loop, &tw); |
1973 | |
2042 | |
1974 | // create one ev_io per pollfd |
2043 | // create one ev_io per pollfd |
1975 | for (int i = 0; i < nfd; ++i) |
2044 | for (int i = 0; i < nfd; ++i) |
1976 | { |
2045 | { |
1977 | ev_io_init (iow + i, io_cb, fds [i].fd, |
2046 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1978 | ((fds [i].events & POLLIN ? EV_READ : 0) |
2047 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1979 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
2048 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1980 | |
2049 | |
1981 | fds [i].revents = 0; |
2050 | fds [i].revents = 0; |
1982 | ev_io_start (loop, iow + i); |
2051 | ev_io_start (loop, iow + i); |
1983 | } |
2052 | } |
1984 | } |
2053 | } |
1985 | |
2054 | |
1986 | // stop all watchers after blocking |
2055 | // stop all watchers after blocking |
1987 | static void |
2056 | static void |
1988 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
2057 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1989 | { |
2058 | { |
1990 | ev_timer_stop (loop, &tw); |
2059 | ev_timer_stop (loop, &tw); |
1991 | |
2060 | |
1992 | for (int i = 0; i < nfd; ++i) |
2061 | for (int i = 0; i < nfd; ++i) |
1993 | { |
2062 | { |
1994 | // set the relevant poll flags |
2063 | // set the relevant poll flags |
1995 | // could also call adns_processreadable etc. here |
2064 | // could also call adns_processreadable etc. here |
1996 | struct pollfd *fd = fds + i; |
2065 | struct pollfd *fd = fds + i; |
1997 | int revents = ev_clear_pending (iow + i); |
2066 | int revents = ev_clear_pending (iow + i); |
1998 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
2067 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1999 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
2068 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
2000 | |
2069 | |
2001 | // now stop the watcher |
2070 | // now stop the watcher |
2002 | ev_io_stop (loop, iow + i); |
2071 | ev_io_stop (loop, iow + i); |
2003 | } |
2072 | } |
2004 | |
2073 | |
2005 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
2074 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
2006 | } |
2075 | } |
2007 | |
2076 | |
2008 | Method 2: This would be just like method 1, but you run C<adns_afterpoll> |
2077 | Method 2: This would be just like method 1, but you run C<adns_afterpoll> |
2009 | in the prepare watcher and would dispose of the check watcher. |
2078 | in the prepare watcher and would dispose of the check watcher. |
2010 | |
2079 | |
2011 | Method 3: If the module to be embedded supports explicit event |
2080 | Method 3: If the module to be embedded supports explicit event |
2012 | notification (libadns does), you can also make use of the actual watcher |
2081 | notification (libadns does), you can also make use of the actual watcher |
2013 | callbacks, and only destroy/create the watchers in the prepare watcher. |
2082 | callbacks, and only destroy/create the watchers in the prepare watcher. |
2014 | |
2083 | |
2015 | static void |
2084 | static void |
2016 | timer_cb (EV_P_ ev_timer *w, int revents) |
2085 | timer_cb (EV_P_ ev_timer *w, int revents) |
2017 | { |
2086 | { |
2018 | adns_state ads = (adns_state)w->data; |
2087 | adns_state ads = (adns_state)w->data; |
2019 | update_now (EV_A); |
2088 | update_now (EV_A); |
2020 | |
2089 | |
2021 | adns_processtimeouts (ads, &tv_now); |
2090 | adns_processtimeouts (ads, &tv_now); |
2022 | } |
2091 | } |
2023 | |
2092 | |
2024 | static void |
2093 | static void |
2025 | io_cb (EV_P_ ev_io *w, int revents) |
2094 | io_cb (EV_P_ ev_io *w, int revents) |
2026 | { |
2095 | { |
2027 | adns_state ads = (adns_state)w->data; |
2096 | adns_state ads = (adns_state)w->data; |
2028 | update_now (EV_A); |
2097 | update_now (EV_A); |
2029 | |
2098 | |
2030 | if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
2099 | if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
2031 | if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
2100 | if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
2032 | } |
2101 | } |
2033 | |
2102 | |
2034 | // do not ever call adns_afterpoll |
2103 | // do not ever call adns_afterpoll |
2035 | |
2104 | |
2036 | Method 4: Do not use a prepare or check watcher because the module you |
2105 | Method 4: Do not use a prepare or check watcher because the module you |
2037 | want to embed is too inflexible to support it. Instead, you can override |
2106 | want to embed is too inflexible to support it. Instead, you can override |
2038 | their poll function. The drawback with this solution is that the main |
2107 | their poll function. The drawback with this solution is that the main |
2039 | loop is now no longer controllable by EV. The C<Glib::EV> module does |
2108 | loop is now no longer controllable by EV. The C<Glib::EV> module does |
2040 | this. |
2109 | this. |
2041 | |
2110 | |
2042 | static gint |
2111 | static gint |
2043 | event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
2112 | event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
2044 | { |
2113 | { |
2045 | int got_events = 0; |
2114 | int got_events = 0; |
2046 | |
2115 | |
2047 | for (n = 0; n < nfds; ++n) |
2116 | for (n = 0; n < nfds; ++n) |
2048 | // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
2117 | // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
2049 | |
2118 | |
2050 | if (timeout >= 0) |
2119 | if (timeout >= 0) |
2051 | // create/start timer |
2120 | // create/start timer |
2052 | |
2121 | |
2053 | // poll |
2122 | // poll |
2054 | ev_loop (EV_A_ 0); |
2123 | ev_loop (EV_A_ 0); |
2055 | |
2124 | |
2056 | // stop timer again |
2125 | // stop timer again |
2057 | if (timeout >= 0) |
2126 | if (timeout >= 0) |
2058 | ev_timer_stop (EV_A_ &to); |
2127 | ev_timer_stop (EV_A_ &to); |
2059 | |
2128 | |
2060 | // stop io watchers again - their callbacks should have set |
2129 | // stop io watchers again - their callbacks should have set |
2061 | for (n = 0; n < nfds; ++n) |
2130 | for (n = 0; n < nfds; ++n) |
2062 | ev_io_stop (EV_A_ iow [n]); |
2131 | ev_io_stop (EV_A_ iow [n]); |
2063 | |
2132 | |
2064 | return got_events; |
2133 | return got_events; |
2065 | } |
2134 | } |
2066 | |
2135 | |
2067 | |
2136 | |
2068 | =head2 C<ev_embed> - when one backend isn't enough... |
2137 | =head2 C<ev_embed> - when one backend isn't enough... |
2069 | |
2138 | |
2070 | This is a rather advanced watcher type that lets you embed one event loop |
2139 | This is a rather advanced watcher type that lets you embed one event loop |
… | |
… | |
2148 | event loop. If that is not possible, use the default loop. The default |
2217 | event loop. If that is not possible, use the default loop. The default |
2149 | loop is stored in C<loop_hi>, while the embeddable loop is stored in |
2218 | loop is stored in C<loop_hi>, while the embeddable loop is stored in |
2150 | C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be |
2219 | C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be |
2151 | used). |
2220 | used). |
2152 | |
2221 | |
2153 | struct ev_loop *loop_hi = ev_default_init (0); |
2222 | struct ev_loop *loop_hi = ev_default_init (0); |
2154 | struct ev_loop *loop_lo = 0; |
2223 | struct ev_loop *loop_lo = 0; |
2155 | struct ev_embed embed; |
2224 | struct ev_embed embed; |
2156 | |
2225 | |
2157 | // see if there is a chance of getting one that works |
2226 | // see if there is a chance of getting one that works |
2158 | // (remember that a flags value of 0 means autodetection) |
2227 | // (remember that a flags value of 0 means autodetection) |
2159 | loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
2228 | loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
2160 | ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
2229 | ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
2161 | : 0; |
2230 | : 0; |
2162 | |
2231 | |
2163 | // if we got one, then embed it, otherwise default to loop_hi |
2232 | // if we got one, then embed it, otherwise default to loop_hi |
2164 | if (loop_lo) |
2233 | if (loop_lo) |
2165 | { |
2234 | { |
2166 | ev_embed_init (&embed, 0, loop_lo); |
2235 | ev_embed_init (&embed, 0, loop_lo); |
2167 | ev_embed_start (loop_hi, &embed); |
2236 | ev_embed_start (loop_hi, &embed); |
2168 | } |
2237 | } |
2169 | else |
2238 | else |
2170 | loop_lo = loop_hi; |
2239 | loop_lo = loop_hi; |
2171 | |
2240 | |
2172 | Example: Check if kqueue is available but not recommended and create |
2241 | Example: Check if kqueue is available but not recommended and create |
2173 | a kqueue backend for use with sockets (which usually work with any |
2242 | a kqueue backend for use with sockets (which usually work with any |
2174 | kqueue implementation). Store the kqueue/socket-only event loop in |
2243 | kqueue implementation). Store the kqueue/socket-only event loop in |
2175 | C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). |
2244 | C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). |
2176 | |
2245 | |
2177 | struct ev_loop *loop = ev_default_init (0); |
2246 | struct ev_loop *loop = ev_default_init (0); |
2178 | struct ev_loop *loop_socket = 0; |
2247 | struct ev_loop *loop_socket = 0; |
2179 | struct ev_embed embed; |
2248 | struct ev_embed embed; |
2180 | |
2249 | |
2181 | if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
2250 | if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
2182 | if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
2251 | if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
2183 | { |
2252 | { |
2184 | ev_embed_init (&embed, 0, loop_socket); |
2253 | ev_embed_init (&embed, 0, loop_socket); |
2185 | ev_embed_start (loop, &embed); |
2254 | ev_embed_start (loop, &embed); |
2186 | } |
2255 | } |
2187 | |
2256 | |
2188 | if (!loop_socket) |
2257 | if (!loop_socket) |
2189 | loop_socket = loop; |
2258 | loop_socket = loop; |
2190 | |
2259 | |
2191 | // now use loop_socket for all sockets, and loop for everything else |
2260 | // now use loop_socket for all sockets, and loop for everything else |
2192 | |
2261 | |
2193 | |
2262 | |
2194 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
2263 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
2195 | |
2264 | |
2196 | Fork watchers are called when a C<fork ()> was detected (usually because |
2265 | Fork watchers are called when a C<fork ()> was detected (usually because |
… | |
… | |
2385 | The callback has the type C<void (*cb)(int revents, void *arg)> and gets |
2454 | The callback has the type C<void (*cb)(int revents, void *arg)> and gets |
2386 | passed an C<revents> set like normal event callbacks (a combination of |
2455 | passed an C<revents> set like normal event callbacks (a combination of |
2387 | C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg> |
2456 | C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg> |
2388 | value passed to C<ev_once>: |
2457 | value passed to C<ev_once>: |
2389 | |
2458 | |
2390 | static void stdin_ready (int revents, void *arg) |
2459 | static void stdin_ready (int revents, void *arg) |
2391 | { |
2460 | { |
2392 | if (revents & EV_TIMEOUT) |
2461 | if (revents & EV_TIMEOUT) |
2393 | /* doh, nothing entered */; |
2462 | /* doh, nothing entered */; |
2394 | else if (revents & EV_READ) |
2463 | else if (revents & EV_READ) |
2395 | /* stdin might have data for us, joy! */; |
2464 | /* stdin might have data for us, joy! */; |
2396 | } |
2465 | } |
2397 | |
2466 | |
2398 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
2467 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
2399 | |
2468 | |
2400 | =item ev_feed_event (ev_loop *, watcher *, int revents) |
2469 | =item ev_feed_event (ev_loop *, watcher *, int revents) |
2401 | |
2470 | |
2402 | Feeds the given event set into the event loop, as if the specified event |
2471 | Feeds the given event set into the event loop, as if the specified event |
2403 | had happened for the specified watcher (which must be a pointer to an |
2472 | had happened for the specified watcher (which must be a pointer to an |
… | |
… | |
2452 | you to use some convenience methods to start/stop watchers and also change |
2521 | you to use some convenience methods to start/stop watchers and also change |
2453 | the callback model to a model using method callbacks on objects. |
2522 | the callback model to a model using method callbacks on objects. |
2454 | |
2523 | |
2455 | To use it, |
2524 | To use it, |
2456 | |
2525 | |
2457 | #include <ev++.h> |
2526 | #include <ev++.h> |
2458 | |
2527 | |
2459 | This automatically includes F<ev.h> and puts all of its definitions (many |
2528 | This automatically includes F<ev.h> and puts all of its definitions (many |
2460 | of them macros) into the global namespace. All C++ specific things are |
2529 | of them macros) into the global namespace. All C++ specific things are |
2461 | put into the C<ev> namespace. It should support all the same embedding |
2530 | put into the C<ev> namespace. It should support all the same embedding |
2462 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
2531 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
… | |
… | |
2529 | your compiler is good :), then the method will be fully inlined into the |
2598 | your compiler is good :), then the method will be fully inlined into the |
2530 | thunking function, making it as fast as a direct C callback. |
2599 | thunking function, making it as fast as a direct C callback. |
2531 | |
2600 | |
2532 | Example: simple class declaration and watcher initialisation |
2601 | Example: simple class declaration and watcher initialisation |
2533 | |
2602 | |
2534 | struct myclass |
2603 | struct myclass |
2535 | { |
2604 | { |
2536 | void io_cb (ev::io &w, int revents) { } |
2605 | void io_cb (ev::io &w, int revents) { } |
2537 | } |
2606 | } |
2538 | |
2607 | |
2539 | myclass obj; |
2608 | myclass obj; |
2540 | ev::io iow; |
2609 | ev::io iow; |
2541 | iow.set <myclass, &myclass::io_cb> (&obj); |
2610 | iow.set <myclass, &myclass::io_cb> (&obj); |
2542 | |
2611 | |
2543 | =item w->set<function> (void *data = 0) |
2612 | =item w->set<function> (void *data = 0) |
2544 | |
2613 | |
2545 | Also sets a callback, but uses a static method or plain function as |
2614 | Also sets a callback, but uses a static method or plain function as |
2546 | callback. The optional C<data> argument will be stored in the watcher's |
2615 | callback. The optional C<data> argument will be stored in the watcher's |
… | |
… | |
2550 | |
2619 | |
2551 | See the method-C<set> above for more details. |
2620 | See the method-C<set> above for more details. |
2552 | |
2621 | |
2553 | Example: |
2622 | Example: |
2554 | |
2623 | |
2555 | static void io_cb (ev::io &w, int revents) { } |
2624 | static void io_cb (ev::io &w, int revents) { } |
2556 | iow.set <io_cb> (); |
2625 | iow.set <io_cb> (); |
2557 | |
2626 | |
2558 | =item w->set (struct ev_loop *) |
2627 | =item w->set (struct ev_loop *) |
2559 | |
2628 | |
2560 | Associates a different C<struct ev_loop> with this watcher. You can only |
2629 | Associates a different C<struct ev_loop> with this watcher. You can only |
2561 | do this when the watcher is inactive (and not pending either). |
2630 | do this when the watcher is inactive (and not pending either). |
… | |
… | |
2594 | =back |
2663 | =back |
2595 | |
2664 | |
2596 | Example: Define a class with an IO and idle watcher, start one of them in |
2665 | Example: Define a class with an IO and idle watcher, start one of them in |
2597 | the constructor. |
2666 | the constructor. |
2598 | |
2667 | |
2599 | class myclass |
2668 | class myclass |
2600 | { |
2669 | { |
2601 | ev::io io; void io_cb (ev::io &w, int revents); |
2670 | ev::io io; void io_cb (ev::io &w, int revents); |
2602 | ev:idle idle void idle_cb (ev::idle &w, int revents); |
2671 | ev:idle idle void idle_cb (ev::idle &w, int revents); |
2603 | |
2672 | |
2604 | myclass (int fd) |
2673 | myclass (int fd) |
2605 | { |
2674 | { |
2606 | io .set <myclass, &myclass::io_cb > (this); |
2675 | io .set <myclass, &myclass::io_cb > (this); |
2607 | idle.set <myclass, &myclass::idle_cb> (this); |
2676 | idle.set <myclass, &myclass::idle_cb> (this); |
2608 | |
2677 | |
2609 | io.start (fd, ev::READ); |
2678 | io.start (fd, ev::READ); |
2610 | } |
2679 | } |
2611 | }; |
2680 | }; |
2612 | |
2681 | |
2613 | |
2682 | |
2614 | =head1 OTHER LANGUAGE BINDINGS |
2683 | =head1 OTHER LANGUAGE BINDINGS |
2615 | |
2684 | |
2616 | Libev does not offer other language bindings itself, but bindings for a |
2685 | Libev does not offer other language bindings itself, but bindings for a |
… | |
… | |
2626 | libev. EV is developed together with libev. Apart from the EV core module, |
2695 | libev. EV is developed together with libev. Apart from the EV core module, |
2627 | there are additional modules that implement libev-compatible interfaces |
2696 | there are additional modules that implement libev-compatible interfaces |
2628 | to C<libadns> (C<EV::ADNS>), C<Net::SNMP> (C<Net::SNMP::EV>) and the |
2697 | to C<libadns> (C<EV::ADNS>), C<Net::SNMP> (C<Net::SNMP::EV>) and the |
2629 | C<libglib> event core (C<Glib::EV> and C<EV::Glib>). |
2698 | C<libglib> event core (C<Glib::EV> and C<EV::Glib>). |
2630 | |
2699 | |
2631 | It can be found and installed via CPAN, its homepage is found at |
2700 | It can be found and installed via CPAN, its homepage is at |
2632 | L<http://software.schmorp.de/pkg/EV>. |
2701 | L<http://software.schmorp.de/pkg/EV>. |
|
|
2702 | |
|
|
2703 | =item Python |
|
|
2704 | |
|
|
2705 | Python bindings can be found at L<http://code.google.com/p/pyev/>. It |
|
|
2706 | seems to be quite complete and well-documented. Note, however, that the |
|
|
2707 | patch they require for libev is outright dangerous as it breaks the ABI |
|
|
2708 | for everybody else, and therefore, should never be applied in an installed |
|
|
2709 | libev (if python requires an incompatible ABI then it needs to embed |
|
|
2710 | libev). |
2633 | |
2711 | |
2634 | =item Ruby |
2712 | =item Ruby |
2635 | |
2713 | |
2636 | Tony Arcieri has written a ruby extension that offers access to a subset |
2714 | Tony Arcieri has written a ruby extension that offers access to a subset |
2637 | of the libev API and adds file handle abstractions, asynchronous DNS and |
2715 | of the libev API and adds file handle abstractions, asynchronous DNS and |
… | |
… | |
2639 | L<http://rev.rubyforge.org/>. |
2717 | L<http://rev.rubyforge.org/>. |
2640 | |
2718 | |
2641 | =item D |
2719 | =item D |
2642 | |
2720 | |
2643 | Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to |
2721 | Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to |
2644 | be found at L<http://git.llucax.com.ar/?p=software/ev.d.git;a=summary>. |
2722 | be found at L<http://proj.llucax.com.ar/wiki/evd>. |
2645 | |
2723 | |
2646 | =back |
2724 | =back |
2647 | |
2725 | |
2648 | |
2726 | |
2649 | =head1 MACRO MAGIC |
2727 | =head1 MACRO MAGIC |
… | |
… | |
2661 | |
2739 | |
2662 | This provides the loop I<argument> for functions, if one is required ("ev |
2740 | This provides the loop I<argument> for functions, if one is required ("ev |
2663 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
2741 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
2664 | C<EV_A_> is used when other arguments are following. Example: |
2742 | C<EV_A_> is used when other arguments are following. Example: |
2665 | |
2743 | |
2666 | ev_unref (EV_A); |
2744 | ev_unref (EV_A); |
2667 | ev_timer_add (EV_A_ watcher); |
2745 | ev_timer_add (EV_A_ watcher); |
2668 | ev_loop (EV_A_ 0); |
2746 | ev_loop (EV_A_ 0); |
2669 | |
2747 | |
2670 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
2748 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
2671 | which is often provided by the following macro. |
2749 | which is often provided by the following macro. |
2672 | |
2750 | |
2673 | =item C<EV_P>, C<EV_P_> |
2751 | =item C<EV_P>, C<EV_P_> |
2674 | |
2752 | |
2675 | This provides the loop I<parameter> for functions, if one is required ("ev |
2753 | This provides the loop I<parameter> for functions, if one is required ("ev |
2676 | loop parameter"). The C<EV_P> form is used when this is the sole parameter, |
2754 | loop parameter"). The C<EV_P> form is used when this is the sole parameter, |
2677 | C<EV_P_> is used when other parameters are following. Example: |
2755 | C<EV_P_> is used when other parameters are following. Example: |
2678 | |
2756 | |
2679 | // this is how ev_unref is being declared |
2757 | // this is how ev_unref is being declared |
2680 | static void ev_unref (EV_P); |
2758 | static void ev_unref (EV_P); |
2681 | |
2759 | |
2682 | // this is how you can declare your typical callback |
2760 | // this is how you can declare your typical callback |
2683 | static void cb (EV_P_ ev_timer *w, int revents) |
2761 | static void cb (EV_P_ ev_timer *w, int revents) |
2684 | |
2762 | |
2685 | It declares a parameter C<loop> of type C<struct ev_loop *>, quite |
2763 | It declares a parameter C<loop> of type C<struct ev_loop *>, quite |
2686 | suitable for use with C<EV_A>. |
2764 | suitable for use with C<EV_A>. |
2687 | |
2765 | |
2688 | =item C<EV_DEFAULT>, C<EV_DEFAULT_> |
2766 | =item C<EV_DEFAULT>, C<EV_DEFAULT_> |
… | |
… | |
2704 | |
2782 | |
2705 | Example: Declare and initialise a check watcher, utilising the above |
2783 | Example: Declare and initialise a check watcher, utilising the above |
2706 | macros so it will work regardless of whether multiple loops are supported |
2784 | macros so it will work regardless of whether multiple loops are supported |
2707 | or not. |
2785 | or not. |
2708 | |
2786 | |
2709 | static void |
2787 | static void |
2710 | check_cb (EV_P_ ev_timer *w, int revents) |
2788 | check_cb (EV_P_ ev_timer *w, int revents) |
2711 | { |
2789 | { |
2712 | ev_check_stop (EV_A_ w); |
2790 | ev_check_stop (EV_A_ w); |
2713 | } |
2791 | } |
2714 | |
2792 | |
2715 | ev_check check; |
2793 | ev_check check; |
2716 | ev_check_init (&check, check_cb); |
2794 | ev_check_init (&check, check_cb); |
2717 | ev_check_start (EV_DEFAULT_ &check); |
2795 | ev_check_start (EV_DEFAULT_ &check); |
2718 | ev_loop (EV_DEFAULT_ 0); |
2796 | ev_loop (EV_DEFAULT_ 0); |
2719 | |
2797 | |
2720 | =head1 EMBEDDING |
2798 | =head1 EMBEDDING |
2721 | |
2799 | |
2722 | Libev can (and often is) directly embedded into host |
2800 | Libev can (and often is) directly embedded into host |
2723 | applications. Examples of applications that embed it include the Deliantra |
2801 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
2737 | =head3 CORE EVENT LOOP |
2815 | =head3 CORE EVENT LOOP |
2738 | |
2816 | |
2739 | To include only the libev core (all the C<ev_*> functions), with manual |
2817 | To include only the libev core (all the C<ev_*> functions), with manual |
2740 | configuration (no autoconf): |
2818 | configuration (no autoconf): |
2741 | |
2819 | |
2742 | #define EV_STANDALONE 1 |
2820 | #define EV_STANDALONE 1 |
2743 | #include "ev.c" |
2821 | #include "ev.c" |
2744 | |
2822 | |
2745 | This will automatically include F<ev.h>, too, and should be done in a |
2823 | This will automatically include F<ev.h>, too, and should be done in a |
2746 | single C source file only to provide the function implementations. To use |
2824 | single C source file only to provide the function implementations. To use |
2747 | it, do the same for F<ev.h> in all files wishing to use this API (best |
2825 | it, do the same for F<ev.h> in all files wishing to use this API (best |
2748 | done by writing a wrapper around F<ev.h> that you can include instead and |
2826 | done by writing a wrapper around F<ev.h> that you can include instead and |
2749 | where you can put other configuration options): |
2827 | where you can put other configuration options): |
2750 | |
2828 | |
2751 | #define EV_STANDALONE 1 |
2829 | #define EV_STANDALONE 1 |
2752 | #include "ev.h" |
2830 | #include "ev.h" |
2753 | |
2831 | |
2754 | Both header files and implementation files can be compiled with a C++ |
2832 | Both header files and implementation files can be compiled with a C++ |
2755 | compiler (at least, thats a stated goal, and breakage will be treated |
2833 | compiler (at least, thats a stated goal, and breakage will be treated |
2756 | as a bug). |
2834 | as a bug). |
2757 | |
2835 | |
2758 | You need the following files in your source tree, or in a directory |
2836 | You need the following files in your source tree, or in a directory |
2759 | in your include path (e.g. in libev/ when using -Ilibev): |
2837 | in your include path (e.g. in libev/ when using -Ilibev): |
2760 | |
2838 | |
2761 | ev.h |
2839 | ev.h |
2762 | ev.c |
2840 | ev.c |
2763 | ev_vars.h |
2841 | ev_vars.h |
2764 | ev_wrap.h |
2842 | ev_wrap.h |
2765 | |
2843 | |
2766 | ev_win32.c required on win32 platforms only |
2844 | ev_win32.c required on win32 platforms only |
2767 | |
2845 | |
2768 | ev_select.c only when select backend is enabled (which is enabled by default) |
2846 | ev_select.c only when select backend is enabled (which is enabled by default) |
2769 | ev_poll.c only when poll backend is enabled (disabled by default) |
2847 | ev_poll.c only when poll backend is enabled (disabled by default) |
2770 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2848 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2771 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2849 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2772 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
2850 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
2773 | |
2851 | |
2774 | F<ev.c> includes the backend files directly when enabled, so you only need |
2852 | F<ev.c> includes the backend files directly when enabled, so you only need |
2775 | to compile this single file. |
2853 | to compile this single file. |
2776 | |
2854 | |
2777 | =head3 LIBEVENT COMPATIBILITY API |
2855 | =head3 LIBEVENT COMPATIBILITY API |
2778 | |
2856 | |
2779 | To include the libevent compatibility API, also include: |
2857 | To include the libevent compatibility API, also include: |
2780 | |
2858 | |
2781 | #include "event.c" |
2859 | #include "event.c" |
2782 | |
2860 | |
2783 | in the file including F<ev.c>, and: |
2861 | in the file including F<ev.c>, and: |
2784 | |
2862 | |
2785 | #include "event.h" |
2863 | #include "event.h" |
2786 | |
2864 | |
2787 | in the files that want to use the libevent API. This also includes F<ev.h>. |
2865 | in the files that want to use the libevent API. This also includes F<ev.h>. |
2788 | |
2866 | |
2789 | You need the following additional files for this: |
2867 | You need the following additional files for this: |
2790 | |
2868 | |
2791 | event.h |
2869 | event.h |
2792 | event.c |
2870 | event.c |
2793 | |
2871 | |
2794 | =head3 AUTOCONF SUPPORT |
2872 | =head3 AUTOCONF SUPPORT |
2795 | |
2873 | |
2796 | Instead of using C<EV_STANDALONE=1> and providing your configuration in |
2874 | Instead of using C<EV_STANDALONE=1> and providing your configuration in |
2797 | whatever way you want, you can also C<m4_include([libev.m4])> in your |
2875 | whatever way you want, you can also C<m4_include([libev.m4])> in your |
2798 | F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then |
2876 | F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then |
2799 | include F<config.h> and configure itself accordingly. |
2877 | include F<config.h> and configure itself accordingly. |
2800 | |
2878 | |
2801 | For this of course you need the m4 file: |
2879 | For this of course you need the m4 file: |
2802 | |
2880 | |
2803 | libev.m4 |
2881 | libev.m4 |
2804 | |
2882 | |
2805 | =head2 PREPROCESSOR SYMBOLS/MACROS |
2883 | =head2 PREPROCESSOR SYMBOLS/MACROS |
2806 | |
2884 | |
2807 | Libev can be configured via a variety of preprocessor symbols you have to |
2885 | Libev can be configured via a variety of preprocessor symbols you have to |
2808 | define before including any of its files. The default in the absence of |
2886 | define before including any of its files. The default in the absence of |
… | |
… | |
3085 | members. You have to define it each time you include one of the files, |
3163 | members. You have to define it each time you include one of the files, |
3086 | though, and it must be identical each time. |
3164 | though, and it must be identical each time. |
3087 | |
3165 | |
3088 | For example, the perl EV module uses something like this: |
3166 | For example, the perl EV module uses something like this: |
3089 | |
3167 | |
3090 | #define EV_COMMON \ |
3168 | #define EV_COMMON \ |
3091 | SV *self; /* contains this struct */ \ |
3169 | SV *self; /* contains this struct */ \ |
3092 | SV *cb_sv, *fh /* note no trailing ";" */ |
3170 | SV *cb_sv, *fh /* note no trailing ";" */ |
3093 | |
3171 | |
3094 | =item EV_CB_DECLARE (type) |
3172 | =item EV_CB_DECLARE (type) |
3095 | |
3173 | |
3096 | =item EV_CB_INVOKE (watcher, revents) |
3174 | =item EV_CB_INVOKE (watcher, revents) |
3097 | |
3175 | |
… | |
… | |
3108 | |
3186 | |
3109 | If you need to re-export the API (e.g. via a DLL) and you need a list of |
3187 | If you need to re-export the API (e.g. via a DLL) and you need a list of |
3110 | exported symbols, you can use the provided F<Symbol.*> files which list |
3188 | exported symbols, you can use the provided F<Symbol.*> files which list |
3111 | all public symbols, one per line: |
3189 | all public symbols, one per line: |
3112 | |
3190 | |
3113 | Symbols.ev for libev proper |
3191 | Symbols.ev for libev proper |
3114 | Symbols.event for the libevent emulation |
3192 | Symbols.event for the libevent emulation |
3115 | |
3193 | |
3116 | This can also be used to rename all public symbols to avoid clashes with |
3194 | This can also be used to rename all public symbols to avoid clashes with |
3117 | multiple versions of libev linked together (which is obviously bad in |
3195 | multiple versions of libev linked together (which is obviously bad in |
3118 | itself, but sometimes it is inconvenient to avoid this). |
3196 | itself, but sometimes it is inconvenient to avoid this). |
3119 | |
3197 | |
… | |
… | |
3140 | file. |
3218 | file. |
3141 | |
3219 | |
3142 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
3220 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
3143 | that everybody includes and which overrides some configure choices: |
3221 | that everybody includes and which overrides some configure choices: |
3144 | |
3222 | |
3145 | #define EV_MINIMAL 1 |
3223 | #define EV_MINIMAL 1 |
3146 | #define EV_USE_POLL 0 |
3224 | #define EV_USE_POLL 0 |
3147 | #define EV_MULTIPLICITY 0 |
3225 | #define EV_MULTIPLICITY 0 |
3148 | #define EV_PERIODIC_ENABLE 0 |
3226 | #define EV_PERIODIC_ENABLE 0 |
3149 | #define EV_STAT_ENABLE 0 |
3227 | #define EV_STAT_ENABLE 0 |
3150 | #define EV_FORK_ENABLE 0 |
3228 | #define EV_FORK_ENABLE 0 |
3151 | #define EV_CONFIG_H <config.h> |
3229 | #define EV_CONFIG_H <config.h> |
3152 | #define EV_MINPRI 0 |
3230 | #define EV_MINPRI 0 |
3153 | #define EV_MAXPRI 0 |
3231 | #define EV_MAXPRI 0 |
3154 | |
3232 | |
3155 | #include "ev++.h" |
3233 | #include "ev++.h" |
3156 | |
3234 | |
3157 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
3235 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
3158 | |
3236 | |
3159 | #include "ev_cpp.h" |
3237 | #include "ev_cpp.h" |
3160 | #include "ev.c" |
3238 | #include "ev.c" |
3161 | |
3239 | |
3162 | |
3240 | |
3163 | =head1 THREADS AND COROUTINES |
3241 | =head1 THREADS AND COROUTINES |
3164 | |
3242 | |
3165 | =head2 THREADS |
3243 | =head2 THREADS |
3166 | |
3244 | |
3167 | Libev itself is completely thread-safe, but it uses no locking. This |
3245 | Libev itself is thread-safe (unless the opposite is specifically |
|
|
3246 | documented for a function), but it uses no locking itself. This means that |
3168 | means that you can use as many loops as you want in parallel, as long as |
3247 | you can use as many loops as you want in parallel, as long as only one |
3169 | only one thread ever calls into one libev function with the same loop |
3248 | thread ever calls into one libev function with the same loop parameter: |
3170 | parameter. |
3249 | libev guarentees that different event loops share no data structures that |
|
|
3250 | need locking. |
3171 | |
3251 | |
3172 | Or put differently: calls with different loop parameters can be done in |
3252 | Or to put it differently: calls with different loop parameters can be done |
3173 | parallel from multiple threads, calls with the same loop parameter must be |
3253 | concurrently from multiple threads, calls with the same loop parameter |
3174 | done serially (but can be done from different threads, as long as only one |
3254 | must be done serially (but can be done from different threads, as long as |
3175 | thread ever is inside a call at any point in time, e.g. by using a mutex |
3255 | only one thread ever is inside a call at any point in time, e.g. by using |
3176 | per loop). |
3256 | a mutex per loop). |
3177 | |
3257 | |
3178 | If you want to know which design is best for your problem, then I cannot |
3258 | Specifically to support threads (and signal handlers), libev implements |
3179 | help you but by giving some generic advice: |
3259 | so-called C<ev_async> watchers, which allow some limited form of |
|
|
3260 | concurrency on the same event loop. |
|
|
3261 | |
|
|
3262 | If you want to know which design (one loop, locking, or multiple loops |
|
|
3263 | without or something else still) is best for your problem, then I cannot |
|
|
3264 | help you. I can give some generic advice however: |
3180 | |
3265 | |
3181 | =over 4 |
3266 | =over 4 |
3182 | |
3267 | |
3183 | =item * most applications have a main thread: use the default libev loop |
3268 | =item * most applications have a main thread: use the default libev loop |
3184 | in that thread, or create a separate thread running only the default loop. |
3269 | in that thread, or create a separate thread running only the default loop. |
… | |
… | |
3198 | better than you currently do :-) |
3283 | better than you currently do :-) |
3199 | |
3284 | |
3200 | =item * often you need to talk to some other thread which blocks in the |
3285 | =item * often you need to talk to some other thread which blocks in the |
3201 | event loop - C<ev_async> watchers can be used to wake them up from other |
3286 | event loop - C<ev_async> watchers can be used to wake them up from other |
3202 | threads safely (or from signal contexts...). |
3287 | threads safely (or from signal contexts...). |
|
|
3288 | |
|
|
3289 | =item * some watcher types are only supported in the default loop - use |
|
|
3290 | C<ev_async> watchers to tell your other loops about any such events. |
3203 | |
3291 | |
3204 | =back |
3292 | =back |
3205 | |
3293 | |
3206 | =head2 COROUTINES |
3294 | =head2 COROUTINES |
3207 | |
3295 | |
… | |
… | |
3285 | involves iterating over all running async watchers or all signal numbers. |
3373 | involves iterating over all running async watchers or all signal numbers. |
3286 | |
3374 | |
3287 | =back |
3375 | =back |
3288 | |
3376 | |
3289 | |
3377 | |
3290 | =head1 Win32 platform limitations and workarounds |
3378 | =head1 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS |
3291 | |
3379 | |
3292 | Win32 doesn't support any of the standards (e.g. POSIX) that libev |
3380 | Win32 doesn't support any of the standards (e.g. POSIX) that libev |
3293 | requires, and its I/O model is fundamentally incompatible with the POSIX |
3381 | requires, and its I/O model is fundamentally incompatible with the POSIX |
3294 | model. Libev still offers limited functionality on this platform in |
3382 | model. Libev still offers limited functionality on this platform in |
3295 | the form of the C<EVBACKEND_SELECT> backend, and only supports socket |
3383 | the form of the C<EVBACKEND_SELECT> backend, and only supports socket |
… | |
… | |
3317 | more than a hundred or so sockets, then likely it needs to use a totally |
3405 | more than a hundred or so sockets, then likely it needs to use a totally |
3318 | different implementation for windows, as libev offers the POSIX readiness |
3406 | different implementation for windows, as libev offers the POSIX readiness |
3319 | notification model, which cannot be implemented efficiently on windows |
3407 | notification model, which cannot be implemented efficiently on windows |
3320 | (Microsoft monopoly games). |
3408 | (Microsoft monopoly games). |
3321 | |
3409 | |
|
|
3410 | A typical way to use libev under windows is to embed it (see the embedding |
|
|
3411 | section for details) and use the following F<evwrap.h> header file instead |
|
|
3412 | of F<ev.h>: |
|
|
3413 | |
|
|
3414 | #define EV_STANDALONE /* keeps ev from requiring config.h */ |
|
|
3415 | #define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */ |
|
|
3416 | |
|
|
3417 | #include "ev.h" |
|
|
3418 | |
|
|
3419 | And compile the following F<evwrap.c> file into your project (make sure |
|
|
3420 | you do I<not> compile the F<ev.c> or any other embedded soruce files!): |
|
|
3421 | |
|
|
3422 | #include "evwrap.h" |
|
|
3423 | #include "ev.c" |
|
|
3424 | |
3322 | =over 4 |
3425 | =over 4 |
3323 | |
3426 | |
3324 | =item The winsocket select function |
3427 | =item The winsocket select function |
3325 | |
3428 | |
3326 | The winsocket C<select> function doesn't follow POSIX in that it |
3429 | The winsocket C<select> function doesn't follow POSIX in that it |
3327 | requires socket I<handles> and not socket I<file descriptors> (it is |
3430 | requires socket I<handles> and not socket I<file descriptors> (it is |
3328 | also extremely buggy). This makes select very inefficient, and also |
3431 | also extremely buggy). This makes select very inefficient, and also |
3329 | requires a mapping from file descriptors to socket handles. See the |
3432 | requires a mapping from file descriptors to socket handles (the Microsoft |
|
|
3433 | C runtime provides the function C<_open_osfhandle> for this). See the |
3330 | discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and |
3434 | discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and |
3331 | C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info. |
3435 | C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info. |
3332 | |
3436 | |
3333 | The configuration for a "naked" win32 using the Microsoft runtime |
3437 | The configuration for a "naked" win32 using the Microsoft runtime |
3334 | libraries and raw winsocket select is: |
3438 | libraries and raw winsocket select is: |
3335 | |
3439 | |
3336 | #define EV_USE_SELECT 1 |
3440 | #define EV_USE_SELECT 1 |
3337 | #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
3441 | #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
3338 | |
3442 | |
3339 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
3443 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
3340 | complexity in the O(n²) range when using win32. |
3444 | complexity in the O(n²) range when using win32. |
3341 | |
3445 | |
3342 | =item Limited number of file descriptors |
3446 | =item Limited number of file descriptors |
… | |
… | |
3374 | In addition to a working ISO-C implementation, libev relies on a few |
3478 | In addition to a working ISO-C implementation, libev relies on a few |
3375 | additional extensions: |
3479 | additional extensions: |
3376 | |
3480 | |
3377 | =over 4 |
3481 | =over 4 |
3378 | |
3482 | |
|
|
3483 | =item C<void (*)(ev_watcher_type *, int revents)> must have compatible |
|
|
3484 | calling conventions regardless of C<ev_watcher_type *>. |
|
|
3485 | |
|
|
3486 | Libev assumes not only that all watcher pointers have the same internal |
|
|
3487 | structure (guaranteed by POSIX but not by ISO C for example), but it also |
|
|
3488 | assumes that the same (machine) code can be used to call any watcher |
|
|
3489 | callback: The watcher callbacks have different type signatures, but libev |
|
|
3490 | calls them using an C<ev_watcher *> internally. |
|
|
3491 | |
3379 | =item C<sig_atomic_t volatile> must be thread-atomic as well |
3492 | =item C<sig_atomic_t volatile> must be thread-atomic as well |
3380 | |
3493 | |
3381 | The type C<sig_atomic_t volatile> (or whatever is defined as |
3494 | The type C<sig_atomic_t volatile> (or whatever is defined as |
3382 | C<EV_ATOMIC_T>) must be atomic w.r.t. accesses from different |
3495 | C<EV_ATOMIC_T>) must be atomic w.r.t. accesses from different |
3383 | threads. This is not part of the specification for C<sig_atomic_t>, but is |
3496 | threads. This is not part of the specification for C<sig_atomic_t>, but is |