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Comparing libev/ev.pod (file contents):
Revision 1.26 by root, Tue Nov 13 03:11:57 2007 UTC vs.
Revision 1.28 by root, Sat Nov 17 02:00:49 2007 UTC

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

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