ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev.pod
(Generate patch)

Comparing libev/ev.pod (file contents):
Revision 1.24 by root, Mon Nov 12 19:20:05 2007 UTC vs.
Revision 1.28 by root, Sat Nov 17 02:00:49 2007 UTC

… …
56 56
57=over 4 57=over 4
58 58
59=item ev_tstamp ev_time () 59=item ev_tstamp ev_time ()
60 60
61Returns the current time as libev would use it. 61Returns the current time as libev would use it. Please note that the
62C<ev_now> function is usually faster and also often returns the timestamp
63you actually want to know.
62 64
63=item int ev_version_major () 65=item int ev_version_major ()
64 66
65=item int ev_version_minor () 67=item int ev_version_minor ()
66 68
… …
237 239
238This flags value could be used to implement alternative looping 240This flags value could be used to implement alternative looping
239constructs, 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
240more generic mechanism. 242more generic mechanism.
241 243
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.
261
242=item ev_unloop (loop, how) 262=item ev_unloop (loop, how)
243 263
244Can 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
245has processed all outstanding events). The C<how> argument must be either 265has processed all outstanding events). The C<how> argument must be either
246C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> call return, or 266C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or
247C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. 267C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.
248 268
249=item ev_ref (loop) 269=item ev_ref (loop)
250 270
251=item ev_unref (loop) 271=item ev_unref (loop)
… …
452given time, and optionally repeating in regular intervals after that. 472given time, and optionally repeating in regular intervals after that.
453 473
454The 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
455times 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
456time, it will still time out after (roughly) and hour. "Roughly" because 476time, it will still time out after (roughly) and hour. "Roughly" because
457detecting time jumps is hard, and soem inaccuracies are unavoidable (the 477detecting time jumps is hard, and some inaccuracies are unavoidable (the
458monotonic clock option helps a lot here). 478monotonic clock option helps a lot here).
459 479
460The relative timeouts are calculated relative to the C<ev_now ()> 480The relative timeouts are calculated relative to the C<ev_now ()>
461time. 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
462of the event triggering whatever timeout you are modifying/starting. If 482of the event triggering whatever timeout you are modifying/starting. If
463you 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
464on the current time, use something like this to adjust for this: 484on the current time, use something like this to adjust for this:
465 485
466 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.
467 491
468=over 4 492=over 4
469 493
470=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)
471 495
… …
518again). 542again).
519 543
520They 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
521triggering an event on eahc midnight, local time. 545triggering an event on eahc midnight, local time.
522 546
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
523=over 4 551=over 4
524 552
525=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)
526 554
527=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)
528 556
529Lots 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
530operation, and we will explain them from simplest to complex: 558operation, and we will explain them from simplest to complex:
531
532 559
533=over 4 560=over 4
534 561
535=item * absolute timer (interval = reschedule_cb = 0) 562=item * absolute timer (interval = reschedule_cb = 0)
536 563

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines