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

Comparing libev/ev.pod (file contents):
Revision 1.27 by root, Wed Nov 14 05:02:07 2007 UTC vs.
Revision 1.31 by root, Fri Nov 23 05:00:45 2007 UTC

…		…
75	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,
76	as this indicates an incompatible change. Minor versions are usually	76	as this indicates an incompatible change. Minor versions are usually
77	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
78	not a problem.	78	not a problem.
79		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.
		95
80	=item ev_set_allocator (void (cb)(void *ptr, long size))	96	=item ev_set_allocator (void (cb)(void *ptr, long size))
81		97
82	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
83	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
84	and free memory (no surprises here). If it returns zero when memory	100	and free memory (no surprises here). If it returns zero when memory
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119	=item struct ev_loop *ev_default_loop (unsigned int flags)	135	=item struct ev_loop *ev_default_loop (unsigned int flags)
120		136
121	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
122	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
123	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
124	flags).	140	flags. If that is troubling you, check C<ev_backend ()> afterwards).
125		141
126	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
127	function.	143	function.
128		144
129	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
130	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).
131		147
132	It supports the following flags:	148	It supports the following flags:
133		149
134	=over 4	150	=over 4
135		151
…		…
145	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will	161	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
146	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
147	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
148	around bugs.	164	around bugs.
149		165
150	=item C<EVMETHOD_SELECT> (portable select backend)	166	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
151		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
152	=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)
153		175
154	=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).
155		180
156	=item C<EVMETHOD_KQUEUE> (some bsds only)	181	=item C<EVBACKEND_EPOLL> (value 4, Linux)
157		182
158	=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).
159		187
160	=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
161		224
162	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
163	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
164	specified, any backend will do.	227	specified, most compiled-in backend will be tried, usually in reverse
165		228	order of their flag values :)
166	=back
167		229
168	=item struct ev_loop *ev_loop_new (unsigned int flags)	230	=item struct ev_loop *ev_loop_new (unsigned int flags)
169		231
170	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
171	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
…		…
188	This function reinitialises the kernel state for backends that have	250	This function reinitialises the kernel state for backends that have
189	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
190	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
191	again makes little sense).	253	again makes little sense).
192		254
193	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
194	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
195	have to call it.	257	fork+exec, you don't have to call it.
196		258
197	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
198	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
199	quite nicely into a call to C<pthread_atfork>:	261	quite nicely into a call to C<pthread_atfork>:
200		262
201	pthread_atfork (0, 0, ev_default_fork);	263	pthread_atfork (0, 0, ev_default_fork);
202		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
203	=item ev_loop_fork (loop)	269	=item ev_loop_fork (loop)
204		270
205	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
206	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
207	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.
208		274
209	=item unsigned int ev_method (loop)	275	=item unsigned int ev_backend (loop)
210		276
211	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
212	use.	278	use.
213		279
214	=item ev_tstamp ev_now (loop)	280	=item ev_tstamp ev_now (loop)
215		281
216	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
…		…
322	*) >>), 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
323	corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>.	389	corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>.
324		390
325	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
326	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
327	reinitialise it or call its set method.	393	reinitialise it or call its set macro.
328		394
329	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
330	(watcher *)> macro. To see whether an event is outstanding (but the	396	(watcher *)> macro. To see whether an event is outstanding (but the
331	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
332	(watcher *)> macro.	398	(watcher *)> macro.
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449	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
450	to the same underlying file/socket etc. description (that is, they share	516	to the same underlying file/socket etc. description (that is, they share
451	the same underlying "file open").	517	the same underlying "file open").
452		518
453	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
454	(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
455	EVMETHOD_POLL).	521	C<EVBACKEND_POLL>).
456		522
457	=over 4	523	=over 4
458		524
459	=item ev_io_init (ev_io *, callback, int fd, int events)	525	=item ev_io_init (ev_io *, callback, int fd, int events)
460		526
…		…
472	given time, and optionally repeating in regular intervals after that.	538	given time, and optionally repeating in regular intervals after that.
473		539
474	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
475	times out after an hour and you reset your system clock to last years	541	times out after an hour and you reset your system clock to last years
476	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
477	detecting time jumps is hard, and soem inaccuracies are unavoidable (the	543	detecting time jumps is hard, and some inaccuracies are unavoidable (the
478	monotonic clock option helps a lot here).	544	monotonic clock option helps a lot here).
479		545
480	The relative timeouts are calculated relative to the C<ev_now ()>	546	The relative timeouts are calculated relative to the C<ev_now ()>
481	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
482	of the event triggering whatever timeout you are modifying/starting. If	548	of the event triggering whatever timeout you are modifying/starting. If
483	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
484	on the current time, use something like this to adjust for this:	550	on the current time, use something like this to adjust for this:
485		551
486	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.
487		557
488	=over 4	558	=over 4
489		559
490	=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)
491		561
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538	again).	608	again).
539		609
540	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
541	triggering an event on eahc midnight, local time.	611	triggering an event on eahc midnight, local time.
542		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
543	=over 4	617	=over 4
544		618
545	=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)
546		620
547	=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)
548		622
549	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
550	operation, and we will explain them from simplest to complex:	624	operation, and we will explain them from simplest to complex:
551
552		625
553	=over 4	626	=over 4
554		627
555	=item * absolute timer (interval = reschedule_cb = 0)	628	=item * absolute timer (interval = reschedule_cb = 0)
556		629

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Comparing libev/ev.pod (file contents): Revision 1.27 by root, Wed Nov 14 05:02:07 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 1.27 by root, Wed Nov 14 05:02:07 2007 UTC vs.
Revision 1.31 by root, Fri Nov 23 05:00:45 2007 UTC