[ViewVC] Diff of: cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.17 by root, Mon Nov 12 08:57:03 2007 UTC vs.
Revision 1.31 by root, Fri Nov 23 05:00:45 2007 UTC

…		…
49	called C<ev_tstamp>, which is what you should use too. It usually aliases	49	called C<ev_tstamp>, which is what you should use too. It usually aliases
50	to the double type in C.	50	to the double type in C.
51		51
52	=head1 GLOBAL FUNCTIONS	52	=head1 GLOBAL FUNCTIONS
53		53
		54	These functions can be called anytime, even before initialising the
		55	library in any way.
		56
54	=over 4	57	=over 4
55		58
56	=item ev_tstamp ev_time ()	59	=item ev_tstamp ev_time ()
57		60
58	Returns the current time as libev would use it.	61	Returns the current time as libev would use it. Please note that the
		62	C<ev_now> function is usually faster and also often returns the timestamp
		63	you actually want to know.
59		64
60	=item int ev_version_major ()	65	=item int ev_version_major ()
61		66
62	=item int ev_version_minor ()	67	=item int ev_version_minor ()
63		68
…		…
69		74
70	Usually, it's a good idea to terminate if the major versions mismatch,	75	Usually, it's a good idea to terminate if the major versions mismatch,
71	as this indicates an incompatible change. Minor versions are usually	76	as this indicates an incompatible change. Minor versions are usually
72	compatible to older versions, so a larger minor version alone is usually	77	compatible to older versions, so a larger minor version alone is usually
73	not a problem.	78	not a problem.
		79
		80	=item unsigned int ev_supported_backends ()
		81
		82	Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*>
		83	value) compiled into this binary of libev (independent of their
		84	availability on the system you are running on). See C<ev_default_loop> for
		85	a description of the set values.
		86
		87	=item unsigned int ev_recommended_backends ()
		88
		89	Return the set of all backends compiled into this binary of libev and also
		90	recommended for this platform. This set is often smaller than the one
		91	returned by C<ev_supported_backends>, as for example kqueue is broken on
		92	most BSDs and will not be autodetected unless you explicitly request it
		93	(assuming you know what you are doing). This is the set of backends that
		94	C<EVFLAG_AUTO> will probe for.
74		95
75	=item ev_set_allocator (void (cb)(void *ptr, long size))	96	=item ev_set_allocator (void (cb)(void *ptr, long size))
76		97
77	Sets the allocation function to use (the prototype is similar to the	98	Sets the allocation function to use (the prototype is similar to the
78	realloc C function, the semantics are identical). It is used to allocate	99	realloc C function, the semantics are identical). It is used to allocate
…		…
114	=item struct ev_loop *ev_default_loop (unsigned int flags)	135	=item struct ev_loop *ev_default_loop (unsigned int flags)
115		136
116	This will initialise the default event loop if it hasn't been initialised	137	This will initialise the default event loop if it hasn't been initialised
117	yet and return it. If the default loop could not be initialised, returns	138	yet and return it. If the default loop could not be initialised, returns
118	false. If it already was initialised it simply returns it (and ignores the	139	false. If it already was initialised it simply returns it (and ignores the
119	flags).	140	flags. If that is troubling you, check C<ev_backend ()> afterwards).
120		141
121	If you don't know what event loop to use, use the one returned from this	142	If you don't know what event loop to use, use the one returned from this
122	function.	143	function.
123		144
124	The flags argument can be used to specify special behaviour or specific	145	The flags argument can be used to specify special behaviour or specific
125	backends to use, and is usually specified as 0 (or EVFLAG_AUTO).	146	backends to use, and is usually specified as C<0> (or EVFLAG_AUTO).
126		147
127	It supports the following flags:	148	It supports the following flags:
128		149
129	=over 4	150	=over 4
130		151
…		…
140	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will	161	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
141	override the flags completely if it is found in the environment. This is	162	override the flags completely if it is found in the environment. This is
142	useful to try out specific backends to test their performance, or to work	163	useful to try out specific backends to test their performance, or to work
143	around bugs.	164	around bugs.
144		165
145	=item C<EVMETHOD_SELECT> (portable select backend)	166	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
146		167
		168	This is your standard select(2) backend. Not I<completely> standard, as
		169	libev tries to roll its own fd_set with no limits on the number of fds,
		170	but if that fails, expect a fairly low limit on the number of fds when
		171	using this backend. It doesn't scale too well (O(highest_fd)), but its usually
		172	the fastest backend for a low number of fds.
		173
147	=item C<EVMETHOD_POLL> (poll backend, available everywhere except on windows)	174	=item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows)
148		175
149	=item C<EVMETHOD_EPOLL> (linux only)	176	And this is your standard poll(2) backend. It's more complicated than
		177	select, but handles sparse fds better and has no artificial limit on the
		178	number of fds you can use (except it will slow down considerably with a
		179	lot of inactive fds). It scales similarly to select, i.e. O(total_fds).
150		180
151	=item C<EVMETHOD_KQUEUE> (some bsds only)	181	=item C<EVBACKEND_EPOLL> (value 4, Linux)
152		182
153	=item C<EVMETHOD_DEVPOLL> (solaris 8 only)	183	For few fds, this backend is a bit little slower than poll and select,
		184	but it scales phenomenally better. While poll and select usually scale like
		185	O(total_fds) where n is the total number of fds (or the highest fd), epoll scales
		186	either O(1) or O(active_fds).
154		187
155	=item C<EVMETHOD_PORT> (solaris 10 only)	188	While stopping and starting an I/O watcher in the same iteration will
		189	result in some caching, there is still a syscall per such incident
		190	(because the fd could point to a different file description now), so its
		191	best to avoid that. Also, dup()ed file descriptors might not work very
		192	well if you register events for both fds.
		193
		194	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
		195
		196	Kqueue deserves special mention, as at the time of this writing, it
		197	was broken on all BSDs except NetBSD (usually it doesn't work with
		198	anything but sockets and pipes, except on Darwin, where of course its
		199	completely useless). For this reason its not being "autodetected" unless
		200	you explicitly specify the flags (i.e. you don't use EVFLAG_AUTO).
		201
		202	It scales in the same way as the epoll backend, but the interface to the
		203	kernel is more efficient (which says nothing about its actual speed, of
		204	course). While starting and stopping an I/O watcher does not cause an
		205	extra syscall as with epoll, it still adds up to four event changes per
		206	incident, so its best to avoid that.
		207
		208	=item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8)
		209
		210	This is not implemented yet (and might never be).
		211
		212	=item C<EVBACKEND_PORT> (value 32, Solaris 10)
		213
		214	This uses the Solaris 10 port mechanism. As with everything on Solaris,
		215	it's really slow, but it still scales very well (O(active_fds)).
		216
		217	=item C<EVBACKEND_ALL>
		218
		219	Try all backends (even potentially broken ones that wouldn't be tried
		220	with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as
		221	C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.
		222
		223	=back
156		224
157	If one or more of these are ored into the flags value, then only these	225	If one or more of these are ored into the flags value, then only these
158	backends will be tried (in the reverse order as given here). If one are	226	backends will be tried (in the reverse order as given here). If none are
159	specified, any backend will do.	227	specified, most compiled-in backend will be tried, usually in reverse
160		228	order of their flag values :)
161	=back
162		229
163	=item struct ev_loop *ev_loop_new (unsigned int flags)	230	=item struct ev_loop *ev_loop_new (unsigned int flags)
164		231
165	Similar to C<ev_default_loop>, but always creates a new event loop that is	232	Similar to C<ev_default_loop>, but always creates a new event loop that is
166	always distinct from the default loop. Unlike the default loop, it cannot	233	always distinct from the default loop. Unlike the default loop, it cannot
…		…
183	This function reinitialises the kernel state for backends that have	250	This function reinitialises the kernel state for backends that have
184	one. Despite the name, you can call it anytime, but it makes most sense	251	one. Despite the name, you can call it anytime, but it makes most sense
185	after forking, in either the parent or child process (or both, but that	252	after forking, in either the parent or child process (or both, but that
186	again makes little sense).	253	again makes little sense).
187		254
188	You I<must> call this function after forking if and only if you want to	255	You I<must> call this function in the child process after forking if and
189	use the event library in both processes. If you just fork+exec, you don't	256	only if you want to use the event library in both processes. If you just
190	have to call it.	257	fork+exec, you don't have to call it.
191		258
192	The function itself is quite fast and it's usually not a problem to call	259	The function itself is quite fast and it's usually not a problem to call
193	it just in case after a fork. To make this easy, the function will fit in	260	it just in case after a fork. To make this easy, the function will fit in
194	quite nicely into a call to C<pthread_atfork>:	261	quite nicely into a call to C<pthread_atfork>:
195		262
196	pthread_atfork (0, 0, ev_default_fork);	263	pthread_atfork (0, 0, ev_default_fork);
197		264
		265	At the moment, C<EVBACKEND_SELECT> and C<EVBACKEND_POLL> are safe to use
		266	without calling this function, so if you force one of those backends you
		267	do not need to care.
		268
198	=item ev_loop_fork (loop)	269	=item ev_loop_fork (loop)
199		270
200	Like C<ev_default_fork>, but acts on an event loop created by	271	Like C<ev_default_fork>, but acts on an event loop created by
201	C<ev_loop_new>. Yes, you have to call this on every allocated event loop	272	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
202	after fork, and how you do this is entirely your own problem.	273	after fork, and how you do this is entirely your own problem.
203		274
204	=item unsigned int ev_method (loop)	275	=item unsigned int ev_backend (loop)
205		276
206	Returns one of the C<EVMETHOD_*> flags indicating the event backend in	277	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
207	use.	278	use.
208		279
209	=item ev_tstamp ev_now (loop)	280	=item ev_tstamp ev_now (loop)
210		281
211	Returns the current "event loop time", which is the time the event loop	282	Returns the current "event loop time", which is the time the event loop
…		…
234		305
235	This flags value could be used to implement alternative looping	306	This flags value could be used to implement alternative looping
236	constructs, but the C<prepare> and C<check> watchers provide a better and	307	constructs, but the C<prepare> and C<check> watchers provide a better and
237	more generic mechanism.	308	more generic mechanism.
238		309
		310	Here are the gory details of what ev_loop does:
		311
		312	1. If there are no active watchers (reference count is zero), return.
		313	2. Queue and immediately call all prepare watchers.
		314	3. If we have been forked, recreate the kernel state.
		315	4. Update the kernel state with all outstanding changes.
		316	5. Update the "event loop time".
		317	6. Calculate for how long to block.
		318	7. Block the process, waiting for events.
		319	8. Update the "event loop time" and do time jump handling.
		320	9. Queue all outstanding timers.
		321	10. Queue all outstanding periodics.
		322	11. If no events are pending now, queue all idle watchers.
		323	12. Queue all check watchers.
		324	13. Call all queued watchers in reverse order (i.e. check watchers first).
		325	14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
		326	was used, return, otherwise continue with step #1.
		327
239	=item ev_unloop (loop, how)	328	=item ev_unloop (loop, how)
240		329
241	Can be used to make a call to C<ev_loop> return early (but only after it	330	Can be used to make a call to C<ev_loop> return early (but only after it
242	has processed all outstanding events). The C<how> argument must be either	331	has processed all outstanding events). The C<how> argument must be either
243	C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> call return, or	332	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or
244	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	333	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.
245		334
246	=item ev_ref (loop)	335	=item ev_ref (loop)
247		336
248	=item ev_unref (loop)	337	=item ev_unref (loop)
…		…
299	*) >>), and you can stop watching for events at any time by calling the	388	*) >>), and you can stop watching for events at any time by calling the
300	corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>.	389	corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>.
301		390
302	As long as your watcher is active (has been started but not stopped) you	391	As long as your watcher is active (has been started but not stopped) you
303	must not touch the values stored in it. Most specifically you must never	392	must not touch the values stored in it. Most specifically you must never
304	reinitialise it or call its set method.	393	reinitialise it or call its set macro.
305		394
306	You can check whether an event is active by calling the C<ev_is_active	395	You can check whether an event is active by calling the C<ev_is_active
307	(watcher *)> macro. To see whether an event is outstanding (but the	396	(watcher *)> macro. To see whether an event is outstanding (but the
308	callback for it has not been called yet) you can use the C<ev_is_pending	397	callback for it has not been called yet) you can use the C<ev_is_pending
309	(watcher *)> macro.	398	(watcher *)> macro.
…		…
414	in each iteration of the event loop (This behaviour is called	503	in each iteration of the event loop (This behaviour is called
415	level-triggering because you keep receiving events as long as the	504	level-triggering because you keep receiving events as long as the
416	condition persists. Remember you can stop the watcher if you don't want to	505	condition persists. Remember you can stop the watcher if you don't want to
417	act on the event and neither want to receive future events).	506	act on the event and neither want to receive future events).
418		507
419	In general you can register as many read and/or write event watchers oer	508	In general you can register as many read and/or write event watchers per
420	fd as you want (as long as you don't confuse yourself). Setting all file	509	fd as you want (as long as you don't confuse yourself). Setting all file
421	descriptors to non-blocking mode is also usually a good idea (but not	510	descriptors to non-blocking mode is also usually a good idea (but not
422	required if you know what you are doing).	511	required if you know what you are doing).
423		512
424	You have to be careful with dup'ed file descriptors, though. Some backends	513	You have to be careful with dup'ed file descriptors, though. Some backends
425	(the linux epoll backend is a notable example) cannot handle dup'ed file	514	(the linux epoll backend is a notable example) cannot handle dup'ed file
426	descriptors correctly if you register interest in two or more fds pointing	515	descriptors correctly if you register interest in two or more fds pointing
427	to the same file/socket etc. description.	516	to the same underlying file/socket etc. description (that is, they share
		517	the same underlying "file open").
428		518
429	If you must do this, then force the use of a known-to-be-good backend	519	If you must do this, then force the use of a known-to-be-good backend
430	(at the time of this writing, this includes only EVMETHOD_SELECT and	520	(at the time of this writing, this includes only C<EVBACKEND_SELECT> and
431	EVMETHOD_POLL).	521	C<EVBACKEND_POLL>).
432		522
433	=over 4	523	=over 4
434		524
435	=item ev_io_init (ev_io *, callback, int fd, int events)	525	=item ev_io_init (ev_io *, callback, int fd, int events)
436		526
…		…
446		536
447	Timer watchers are simple relative timers that generate an event after a	537	Timer watchers are simple relative timers that generate an event after a
448	given time, and optionally repeating in regular intervals after that.	538	given time, and optionally repeating in regular intervals after that.
449		539
450	The timers are based on real time, that is, if you register an event that	540	The timers are based on real time, that is, if you register an event that
451	times out after an hour and youreset your system clock to last years	541	times out after an hour and you reset your system clock to last years
452	time, it will still time out after (roughly) and hour. "Roughly" because	542	time, it will still time out after (roughly) and hour. "Roughly" because
453	detecting time jumps is hard, and soem inaccuracies are unavoidable (the	543	detecting time jumps is hard, and some inaccuracies are unavoidable (the
454	monotonic clock option helps a lot here).	544	monotonic clock option helps a lot here).
455		545
456	The relative timeouts are calculated relative to the C<ev_now ()>	546	The relative timeouts are calculated relative to the C<ev_now ()>
457	time. This is usually the right thing as this timestamp refers to the time	547	time. This is usually the right thing as this timestamp refers to the time
458	of the event triggering whatever timeout you are modifying/starting. If	548	of the event triggering whatever timeout you are modifying/starting. If
459	you suspect event processing to be delayed and you need to base the timeout	549	you suspect event processing to be delayed and you I<need> to base the timeout
460	ion the current time, use something like this to adjust for this:	550	on the current time, use something like this to adjust for this:
461		551
462	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);	552	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
		553
		554	The callback is guarenteed to be invoked only when its timeout has passed,
		555	but if multiple timers become ready during the same loop iteration then
		556	order of execution is undefined.
463		557
464	=over 4	558	=over 4
465		559
466	=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)	560	=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)
467		561
…		…
473	later, again, and again, until stopped manually.	567	later, again, and again, until stopped manually.
474		568
475	The timer itself will do a best-effort at avoiding drift, that is, if you	569	The timer itself will do a best-effort at avoiding drift, that is, if you
476	configure a timer to trigger every 10 seconds, then it will trigger at	570	configure a timer to trigger every 10 seconds, then it will trigger at
477	exactly 10 second intervals. If, however, your program cannot keep up with	571	exactly 10 second intervals. If, however, your program cannot keep up with
478	the timer (ecause it takes longer than those 10 seconds to do stuff) the	572	the timer (because it takes longer than those 10 seconds to do stuff) the
479	timer will not fire more than once per event loop iteration.	573	timer will not fire more than once per event loop iteration.
480		574
481	=item ev_timer_again (loop)	575	=item ev_timer_again (loop)
482		576
483	This will act as if the timer timed out and restart it again if it is	577	This will act as if the timer timed out and restart it again if it is
…		…
514	again).	608	again).
515		609
516	They can also be used to implement vastly more complex timers, such as	610	They can also be used to implement vastly more complex timers, such as
517	triggering an event on eahc midnight, local time.	611	triggering an event on eahc midnight, local time.
518		612
		613	As with timers, the callback is guarenteed to be invoked only when the
		614	time (C<at>) has been passed, but if multiple periodic timers become ready
		615	during the same loop iteration then order of execution is undefined.
		616
519	=over 4	617	=over 4
520		618
521	=item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)	619	=item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)
522		620
523	=item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)	621	=item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)
524		622
525	Lots of arguments, lets sort it out... There are basically three modes of	623	Lots of arguments, lets sort it out... There are basically three modes of
526	operation, and we will explain them from simplest to complex:	624	operation, and we will explain them from simplest to complex:
527
528		625
529	=over 4	626	=over 4
530		627
531	=item * absolute timer (interval = reschedule_cb = 0)	628	=item * absolute timer (interval = reschedule_cb = 0)
532		629
…		…
560	In this mode the values for C<interval> and C<at> are both being	657	In this mode the values for C<interval> and C<at> are both being
561	ignored. Instead, each time the periodic watcher gets scheduled, the	658	ignored. Instead, each time the periodic watcher gets scheduled, the
562	reschedule callback will be called with the watcher as first, and the	659	reschedule callback will be called with the watcher as first, and the
563	current time as second argument.	660	current time as second argument.
564		661
565	NOTE: I<This callback MUST NOT stop or destroy the periodic or any other	662	NOTE: I<This callback MUST NOT stop or destroy any periodic watcher,
566	periodic watcher, ever, or make any event loop modifications>. If you need	663	ever, or make any event loop modifications>. If you need to stop it,
567	to stop it, return C<now + 1e30> (or so, fudge fudge) and stop it afterwards.	664	return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by
568		665	starting a prepare watcher).
569	Also, I<< this callback must always return a time that is later than the
570	passed C<now> value >>. Not even C<now> itself will be ok.
571		666
572	Its prototype is C<ev_tstamp (reschedule_cb)(struct ev_periodic w,	667	Its prototype is C<ev_tstamp (reschedule_cb)(struct ev_periodic w,
573	ev_tstamp now)>, e.g.:	668	ev_tstamp now)>, e.g.:
574		669
575	static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)	670	static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)
…		…
580	It must return the next time to trigger, based on the passed time value	675	It must return the next time to trigger, based on the passed time value
581	(that is, the lowest time value larger than to the second argument). It	676	(that is, the lowest time value larger than to the second argument). It
582	will usually be called just before the callback will be triggered, but	677	will usually be called just before the callback will be triggered, but
583	might be called at other times, too.	678	might be called at other times, too.
584		679
		680	NOTE: I<< This callback must always return a time that is later than the
		681	passed C<now> value >>. Not even C<now> itself will do, it I<must> be larger.
		682
585	This can be used to create very complex timers, such as a timer that	683	This can be used to create very complex timers, such as a timer that
586	triggers on each midnight, local time. To do this, you would calculate the	684	triggers on each midnight, local time. To do this, you would calculate the
587	next midnight after C<now> and return the timestamp value for this. How you do this	685	next midnight after C<now> and return the timestamp value for this. How
588	is, again, up to you (but it is not trivial).	686	you do this is, again, up to you (but it is not trivial, which is the main
		687	reason I omitted it as an example).
589		688
590	=back	689	=back
591		690
592	=item ev_periodic_again (loop, ev_periodic *)	691	=item ev_periodic_again (loop, ev_periodic *)
593		692
…		…
672	=back	771	=back
673		772
674	=head2 C<ev_prepare> and C<ev_check> - customise your event loop	773	=head2 C<ev_prepare> and C<ev_check> - customise your event loop
675		774
676	Prepare and check watchers are usually (but not always) used in tandem:	775	Prepare and check watchers are usually (but not always) used in tandem:
677	Prepare watchers get invoked before the process blocks and check watchers	776	prepare watchers get invoked before the process blocks and check watchers
678	afterwards.	777	afterwards.
679		778
680	Their main purpose is to integrate other event mechanisms into libev. This	779	Their main purpose is to integrate other event mechanisms into libev. This
681	could be used, for example, to track variable changes, implement your own	780	could be used, for example, to track variable changes, implement your own
682	watchers, integrate net-snmp or a coroutine library and lots more.	781	watchers, integrate net-snmp or a coroutine library and lots more.
…		…
685	to be watched by the other library, registering C<ev_io> watchers for	784	to be watched by the other library, registering C<ev_io> watchers for
686	them and starting an C<ev_timer> watcher for any timeouts (many libraries	785	them and starting an C<ev_timer> watcher for any timeouts (many libraries
687	provide just this functionality). Then, in the check watcher you check for	786	provide just this functionality). Then, in the check watcher you check for
688	any events that occured (by checking the pending status of all watchers	787	any events that occured (by checking the pending status of all watchers
689	and stopping them) and call back into the library. The I/O and timer	788	and stopping them) and call back into the library. The I/O and timer
690	callbacks will never actually be called (but must be valid neverthelles,	789	callbacks will never actually be called (but must be valid nevertheless,
691	because you never know, you know?).	790	because you never know, you know?).
692		791
693	As another example, the Perl Coro module uses these hooks to integrate	792	As another example, the Perl Coro module uses these hooks to integrate
694	coroutines into libev programs, by yielding to other active coroutines	793	coroutines into libev programs, by yielding to other active coroutines
695	during each prepare and only letting the process block if no coroutines	794	during each prepare and only letting the process block if no coroutines
696	are ready to run (its actually more complicated, it only runs coroutines	795	are ready to run (it's actually more complicated: it only runs coroutines
697	with priority higher than the event loop and one lower priority once,	796	with priority higher than or equal to the event loop and one coroutine
698	using idle watchers to keep the event loop from blocking if lower-priority	797	of lower priority, but only once, using idle watchers to keep the event
699	coroutines exist, thus mapping low-priority coroutines to idle/background	798	loop from blocking if lower-priority coroutines are active, thus mapping
700	tasks).	799	low-priority coroutines to idle/background tasks).
701		800
702	=over 4	801	=over 4
703		802
704	=item ev_prepare_init (ev_prepare *, callback)	803	=item ev_prepare_init (ev_prepare *, callback)
705		804
…		…
720	=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)	819	=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)
721		820
722	This function combines a simple timer and an I/O watcher, calls your	821	This function combines a simple timer and an I/O watcher, calls your
723	callback on whichever event happens first and automatically stop both	822	callback on whichever event happens first and automatically stop both
724	watchers. This is useful if you want to wait for a single event on an fd	823	watchers. This is useful if you want to wait for a single event on an fd
725	or timeout without havign to allocate/configure/start/stop/free one or	824	or timeout without having to allocate/configure/start/stop/free one or
726	more watchers yourself.	825	more watchers yourself.
727		826
728	If C<fd> is less than 0, then no I/O watcher will be started and events	827	If C<fd> is less than 0, then no I/O watcher will be started and events
729	is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and	828	is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and
730	C<events> set will be craeted and started.	829	C<events> set will be craeted and started.
…		…
733	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	832	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
734	repeat = 0) will be started. While C<0> is a valid timeout, it is of	833	repeat = 0) will be started. While C<0> is a valid timeout, it is of
735	dubious value.	834	dubious value.
736		835
737	The callback has the type C<void (cb)(int revents, void arg)> and gets	836	The callback has the type C<void (cb)(int revents, void arg)> and gets
738	passed an events set like normal event callbacks (with a combination of	837	passed an C<revents> set like normal event callbacks (a combination of
739	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	838	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
740	value passed to C<ev_once>:	839	value passed to C<ev_once>:
741		840
742	static void stdin_ready (int revents, void *arg)	841	static void stdin_ready (int revents, void *arg)
743	{	842	{
…		…
764		863
765	Feed an event as if the given signal occured (loop must be the default loop!).	864	Feed an event as if the given signal occured (loop must be the default loop!).
766		865
767	=back	866	=back
768		867
		868	=head1 LIBEVENT EMULATION
		869
		870	Libev offers a compatibility emulation layer for libevent. It cannot
		871	emulate the internals of libevent, so here are some usage hints:
		872
		873	=over 4
		874
		875	=item * Use it by including <event.h>, as usual.
		876
		877	=item * The following members are fully supported: ev_base, ev_callback,
		878	ev_arg, ev_fd, ev_res, ev_events.
		879
		880	=item * Avoid using ev_flags and the EVLIST_*-macros, while it is
		881	maintained by libev, it does not work exactly the same way as in libevent (consider
		882	it a private API).
		883
		884	=item * Priorities are not currently supported. Initialising priorities
		885	will fail and all watchers will have the same priority, even though there
		886	is an ev_pri field.
		887
		888	=item * Other members are not supported.
		889
		890	=item * The libev emulation is I<not> ABI compatible to libevent, you need
		891	to use the libev header file and library.
		892
		893	=back
		894
		895	=head1 C++ SUPPORT
		896
		897	TBD.
		898
769	=head1 AUTHOR	899	=head1 AUTHOR
770		900
771	Marc Lehmann <libev@schmorp.de>.	901	Marc Lehmann <libev@schmorp.de>.
772		902

Diff Legend

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

Comparing libev/ev.pod (file contents): Revision 1.17 by root, Mon Nov 12 08:57:03 2007 UTC vs. Revision 1.31 by root, Fri Nov 23 05:00:45 2007 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.17 by root, Mon Nov 12 08:57:03 2007 UTC vs.
Revision 1.31 by root, Fri Nov 23 05:00:45 2007 UTC