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238 | one iteration of the loop. |
238 | one iteration of the loop. |
239 | |
239 | |
240 | This flags value could be used to implement alternative looping |
240 | This flags value could be used to implement alternative looping |
241 | constructs, but the C<prepare> and C<check> watchers provide a better and |
241 | constructs, but the C<prepare> and C<check> watchers provide a better and |
242 | more generic mechanism. |
242 | more generic mechanism. |
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243 | |
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244 | Here are the gory details of what ev_loop does: |
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245 | |
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246 | 1. If there are no active watchers (reference count is zero), return. |
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247 | 2. Queue and immediately call all prepare watchers. |
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248 | 3. If we have been forked, recreate the kernel state. |
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249 | 4. Update the kernel state with all outstanding changes. |
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250 | 5. Update the "event loop time". |
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251 | 6. Calculate for how long to block. |
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252 | 7. Block the process, waiting for events. |
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253 | 8. Update the "event loop time" and do time jump handling. |
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254 | 9. Queue all outstanding timers. |
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255 | 10. Queue all outstanding periodics. |
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256 | 11. If no events are pending now, queue all idle watchers. |
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257 | 12. Queue all check watchers. |
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258 | 13. Call all queued watchers in reverse order (i.e. check watchers first). |
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259 | 14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
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260 | was used, return, otherwise continue with step #1. |
243 | |
261 | |
244 | =item ev_unloop (loop, how) |
262 | =item ev_unloop (loop, how) |
245 | |
263 | |
246 | Can be used to make a call to C<ev_loop> return early (but only after it |
264 | Can be used to make a call to C<ev_loop> return early (but only after it |
247 | has processed all outstanding events). The C<how> argument must be either |
265 | has processed all outstanding events). The C<how> argument must be either |
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454 | given time, and optionally repeating in regular intervals after that. |
472 | given time, and optionally repeating in regular intervals after that. |
455 | |
473 | |
456 | The timers are based on real time, that is, if you register an event that |
474 | The timers are based on real time, that is, if you register an event that |
457 | times out after an hour and you reset your system clock to last years |
475 | times out after an hour and you reset your system clock to last years |
458 | time, it will still time out after (roughly) and hour. "Roughly" because |
476 | time, it will still time out after (roughly) and hour. "Roughly" because |
459 | detecting time jumps is hard, and soem inaccuracies are unavoidable (the |
477 | detecting time jumps is hard, and some inaccuracies are unavoidable (the |
460 | monotonic clock option helps a lot here). |
478 | monotonic clock option helps a lot here). |
461 | |
479 | |
462 | The relative timeouts are calculated relative to the C<ev_now ()> |
480 | The relative timeouts are calculated relative to the C<ev_now ()> |
463 | time. This is usually the right thing as this timestamp refers to the time |
481 | time. This is usually the right thing as this timestamp refers to the time |
464 | of the event triggering whatever timeout you are modifying/starting. If |
482 | of the event triggering whatever timeout you are modifying/starting. If |
465 | you suspect event processing to be delayed and you *need* to base the timeout |
483 | you suspect event processing to be delayed and you I<need> to base the timeout |
466 | on the current time, use something like this to adjust for this: |
484 | on the current time, use something like this to adjust for this: |
467 | |
485 | |
468 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
486 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
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487 | |
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488 | The callback is guarenteed to be invoked only when its timeout has passed, |
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489 | but if multiple timers become ready during the same loop iteration then |
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490 | order of execution is undefined. |
469 | |
491 | |
470 | =over 4 |
492 | =over 4 |
471 | |
493 | |
472 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
494 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
473 | |
495 | |
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520 | again). |
542 | again). |
521 | |
543 | |
522 | They can also be used to implement vastly more complex timers, such as |
544 | They can also be used to implement vastly more complex timers, such as |
523 | triggering an event on eahc midnight, local time. |
545 | triggering an event on eahc midnight, local time. |
524 | |
546 | |
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547 | As with timers, the callback is guarenteed to be invoked only when the |
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548 | time (C<at>) has been passed, but if multiple periodic timers become ready |
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549 | during the same loop iteration then order of execution is undefined. |
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550 | |
525 | =over 4 |
551 | =over 4 |
526 | |
552 | |
527 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
553 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
528 | |
554 | |
529 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
555 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
530 | |
556 | |
531 | Lots of arguments, lets sort it out... There are basically three modes of |
557 | Lots of arguments, lets sort it out... There are basically three modes of |
532 | operation, and we will explain them from simplest to complex: |
558 | operation, and we will explain them from simplest to complex: |
533 | |
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534 | |
559 | |
535 | =over 4 |
560 | =over 4 |
536 | |
561 | |
537 | =item * absolute timer (interval = reschedule_cb = 0) |
562 | =item * absolute timer (interval = reschedule_cb = 0) |
538 | |
563 | |