ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev.3
(Generate patch)

Comparing libev/ev.3 (file contents):
Revision 1.1 by root, Tue Nov 13 03:11:57 2007 UTC vs.
Revision 1.2 by root, Sun Nov 18 03:43:24 2007 UTC

… …
127.\} 127.\}
128.rm #[ #] #H #V #F C 128.rm #[ #] #H #V #F C
129.\" ======================================================================== 129.\" ========================================================================
130.\" 130.\"
131.IX Title ""<STANDARD INPUT>" 1" 131.IX Title ""<STANDARD INPUT>" 1"
132.TH "<STANDARD INPUT>" 1 "2007-11-13" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH "<STANDARD INPUT>" 1 "2007-11-18" "perl v5.8.8" "User Contributed Perl Documentation"
133.SH "NAME" 133.SH "NAME"
134libev \- a high performance full\-featured event loop written in C 134libev \- a high performance full\-featured event loop written in C
135.SH "SYNOPSIS" 135.SH "SYNOPSIS"
136.IX Header "SYNOPSIS" 136.IX Header "SYNOPSIS"
137.Vb 1 137.Vb 1
… …
180.IX Header "GLOBAL FUNCTIONS" 180.IX Header "GLOBAL FUNCTIONS"
181These functions can be called anytime, even before initialising the 181These functions can be called anytime, even before initialising the
182library in any way. 182library in any way.
183.IP "ev_tstamp ev_time ()" 4 183.IP "ev_tstamp ev_time ()" 4
184.IX Item "ev_tstamp ev_time ()" 184.IX Item "ev_tstamp ev_time ()"
185Returns the current time as libev would use it. 185Returns the current time as libev would use it. Please note that the
186\&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp
187you actually want to know.
186.IP "int ev_version_major ()" 4 188.IP "int ev_version_major ()" 4
187.IX Item "int ev_version_major ()" 189.IX Item "int ev_version_major ()"
188.PD 0 190.PD 0
189.IP "int ev_version_minor ()" 4 191.IP "int ev_version_minor ()" 4
190.IX Item "int ev_version_minor ()" 192.IX Item "int ev_version_minor ()"
… …
354one iteration of the loop. 356one iteration of the loop.
355.Sp 357.Sp
356This flags value could be used to implement alternative looping 358This flags value could be used to implement alternative looping
357constructs, but the \f(CW\*(C`prepare\*(C'\fR and \f(CW\*(C`check\*(C'\fR watchers provide a better and 359constructs, but the \f(CW\*(C`prepare\*(C'\fR and \f(CW\*(C`check\*(C'\fR watchers provide a better and
358more generic mechanism. 360more generic mechanism.
361.Sp
362Here are the gory details of what ev_loop does:
363.Sp
364.Vb 15
365\& 1. If there are no active watchers (reference count is zero), return.
366\& 2. Queue and immediately call all prepare watchers.
367\& 3. If we have been forked, recreate the kernel state.
368\& 4. Update the kernel state with all outstanding changes.
369\& 5. Update the "event loop time".
370\& 6. Calculate for how long to block.
371\& 7. Block the process, waiting for events.
372\& 8. Update the "event loop time" and do time jump handling.
373\& 9. Queue all outstanding timers.
374\& 10. Queue all outstanding periodics.
375\& 11. If no events are pending now, queue all idle watchers.
376\& 12. Queue all check watchers.
377\& 13. Call all queued watchers in reverse order (i.e. check watchers first).
378\& 14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
379\& was used, return, otherwise continue with step #1.
380.Ve
359.IP "ev_unloop (loop, how)" 4 381.IP "ev_unloop (loop, how)" 4
360.IX Item "ev_unloop (loop, how)" 382.IX Item "ev_unloop (loop, how)"
361Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it 383Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it
362has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either 384has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either
363\&\f(CW\*(C`EVUNLOOP_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_loop\*(C'\fR call return, or 385\&\f(CW\*(C`EVUNLOOP_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_loop\*(C'\fR call return, or
… …
571given time, and optionally repeating in regular intervals after that. 593given time, and optionally repeating in regular intervals after that.
572.PP 594.PP
573The timers are based on real time, that is, if you register an event that 595The timers are based on real time, that is, if you register an event that
574times out after an hour and you reset your system clock to last years 596times out after an hour and you reset your system clock to last years
575time, it will still time out after (roughly) and hour. \*(L"Roughly\*(R" because 597time, it will still time out after (roughly) and hour. \*(L"Roughly\*(R" because
576detecting time jumps is hard, and soem inaccuracies are unavoidable (the 598detecting time jumps is hard, and some inaccuracies are unavoidable (the
577monotonic clock option helps a lot here). 599monotonic clock option helps a lot here).
578.PP 600.PP
579The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR 601The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR
580time. This is usually the right thing as this timestamp refers to the time 602time. This is usually the right thing as this timestamp refers to the time
581of the event triggering whatever timeout you are modifying/starting. If 603of the event triggering whatever timeout you are modifying/starting. If
582you suspect event processing to be delayed and you *need* to base the timeout 604you suspect event processing to be delayed and you \fIneed\fR to base the timeout
583on the current time, use something like this to adjust for this: 605on the current time, use something like this to adjust for this:
584.PP 606.PP
585.Vb 1 607.Vb 1
586\& ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); 608\& ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
587.Ve 609.Ve
610.PP
611The callback is guarenteed to be invoked only when its timeout has passed,
612but if multiple timers become ready during the same loop iteration then
613order of execution is undefined.
588.IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 614.IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4
589.IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 615.IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)"
590.PD 0 616.PD 0
591.IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 617.IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4
592.IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 618.IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)"
… …
634roughly 10 seconds later and of course not if you reset your system time 660roughly 10 seconds later and of course not if you reset your system time
635again). 661again).
636.PP 662.PP
637They can also be used to implement vastly more complex timers, such as 663They can also be used to implement vastly more complex timers, such as
638triggering an event on eahc midnight, local time. 664triggering an event on eahc midnight, local time.
665.PP
666As with timers, the callback is guarenteed to be invoked only when the
667time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready
668during the same loop iteration then order of execution is undefined.
639.IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 669.IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4
640.IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 670.IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)"
641.PD 0 671.PD 0
642.IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 672.IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4
643.IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 673.IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)"

Diff Legend

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