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

Comparing libev/ev.pod (file contents):
Revision 1.303 by root, Thu Oct 14 04:29:34 2010 UTC vs.
Revision 1.337 by root, Sun Oct 31 20:20:20 2010 UTC

…		…
26	puts ("stdin ready");	26	puts ("stdin ready");
27	// for one-shot events, one must manually stop the watcher	27	// for one-shot events, one must manually stop the watcher
28	// with its corresponding stop function.	28	// with its corresponding stop function.
29	ev_io_stop (EV_A_ w);	29	ev_io_stop (EV_A_ w);
30		30
31	// this causes all nested ev_loop's to stop iterating	31	// this causes all nested ev_run's to stop iterating
32	ev_unloop (EV_A_ EVUNLOOP_ALL);	32	ev_break (EV_A_ EVBREAK_ALL);
33	}	33	}
34		34
35	// another callback, this time for a time-out	35	// another callback, this time for a time-out
36	static void	36	static void
37	timeout_cb (EV_P_ ev_timer *w, int revents)	37	timeout_cb (EV_P_ ev_timer *w, int revents)
38	{	38	{
39	puts ("timeout");	39	puts ("timeout");
40	// this causes the innermost ev_loop to stop iterating	40	// this causes the innermost ev_run to stop iterating
41	ev_unloop (EV_A_ EVUNLOOP_ONE);	41	ev_break (EV_A_ EVBREAK_ONE);
42	}	42	}
43		43
44	int	44	int
45	main (void)	45	main (void)
46	{	46	{
47	// use the default event loop unless you have special needs	47	// use the default event loop unless you have special needs
48	struct ev_loop *loop = ev_default_loop (0);	48	struct ev_loop *loop = EV_DEFAULT;
49		49
50	// initialise an io watcher, then start it	50	// initialise an io watcher, then start it
51	// this one will watch for stdin to become readable	51	// this one will watch for stdin to become readable
52	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);	52	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
53	ev_io_start (loop, &stdin_watcher);	53	ev_io_start (loop, &stdin_watcher);
…		…
56	// simple non-repeating 5.5 second timeout	56	// simple non-repeating 5.5 second timeout
57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
58	ev_timer_start (loop, &timeout_watcher);	58	ev_timer_start (loop, &timeout_watcher);
59		59
60	// now wait for events to arrive	60	// now wait for events to arrive
61	ev_loop (loop, 0);	61	ev_run (loop, 0);
62		62
63	// unloop was called, so exit	63	// unloop was called, so exit
64	return 0;	64	return 0;
65	}	65	}
66		66
…		…
77	on event-based programming, nor will it introduce event-based programming	77	on event-based programming, nor will it introduce event-based programming
78	with libev.	78	with libev.
79		79
80	Familiarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
		82
		83	=head1 WHAT TO READ WHEN IN A HURRY
		84
		85	This manual tries to be very detailed, but unfortunately, this also makes
		86	it very long. If you just want to know the basics of libev, I suggest
		87	reading L<ANATOMY OF A WATCHER>, then the L<EXAMPLE PROGRAM> above and
		88	look up the missing functions in L<GLOBAL FUNCTIONS> and the C<ev_io> and
		89	C<ev_timer> sections in L<WATCHER TYPES>.
82		90
83	=head1 ABOUT LIBEV	91	=head1 ABOUT LIBEV
84		92
85	Libev is an event loop: you register interest in certain events (such as a	93	Libev is an event loop: you register interest in certain events (such as a
86	file descriptor being readable or a timeout occurring), and it will manage	94	file descriptor being readable or a timeout occurring), and it will manage
…		…
124	this argument.	132	this argument.
125		133
126	=head2 TIME REPRESENTATION	134	=head2 TIME REPRESENTATION
127		135
128	Libev represents time as a single floating point number, representing	136	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (in practise	137	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	somewhere near the beginning of 1970, details are complicated, don't	138	somewhere near the beginning of 1970, details are complicated, don't
131	ask). This type is called C<ev_tstamp>, which is what you should use	139	ask). This type is called C<ev_tstamp>, which is what you should use
132	too. It usually aliases to the C<double> type in C. When you need to do	140	too. It usually aliases to the C<double> type in C. When you need to do
133	any calculations on it, you should treat it as some floating point value.	141	any calculations on it, you should treat it as some floating point value.
134		142
…		…
165		173
166	=item ev_tstamp ev_time ()	174	=item ev_tstamp ev_time ()
167		175
168	Returns the current time as libev would use it. Please note that the	176	Returns the current time as libev would use it. Please note that the
169	C<ev_now> function is usually faster and also often returns the timestamp	177	C<ev_now> function is usually faster and also often returns the timestamp
170	you actually want to know.	178	you actually want to know. Also interesting is the combination of
		179	C<ev_update_now> and C<ev_now>.
171		180
172	=item ev_sleep (ev_tstamp interval)	181	=item ev_sleep (ev_tstamp interval)
173		182
174	Sleep for the given interval: The current thread will be blocked until	183	Sleep for the given interval: The current thread will be blocked until
175	either it is interrupted or the given time interval has passed. Basically	184	either it is interrupted or the given time interval has passed. Basically
…		…
192	as this indicates an incompatible change. Minor versions are usually	201	as this indicates an incompatible change. Minor versions are usually
193	compatible to older versions, so a larger minor version alone is usually	202	compatible to older versions, so a larger minor version alone is usually
194	not a problem.	203	not a problem.
195		204
196	Example: Make sure we haven't accidentally been linked against the wrong	205	Example: Make sure we haven't accidentally been linked against the wrong
197	version (note, however, that this will not detect ABI mismatches :).	206	version (note, however, that this will not detect other ABI mismatches,
		207	such as LFS or reentrancy).
198		208
199	assert (("libev version mismatch",	209	assert (("libev version mismatch",
200	ev_version_major () == EV_VERSION_MAJOR	210	ev_version_major () == EV_VERSION_MAJOR
201	&& ev_version_minor () >= EV_VERSION_MINOR));	211	&& ev_version_minor () >= EV_VERSION_MINOR));
202		212
…		…
213	assert (("sorry, no epoll, no sex",	223	assert (("sorry, no epoll, no sex",
214	ev_supported_backends () & EVBACKEND_EPOLL));	224	ev_supported_backends () & EVBACKEND_EPOLL));
215		225
216	=item unsigned int ev_recommended_backends ()	226	=item unsigned int ev_recommended_backends ()
217		227
218	Return the set of all backends compiled into this binary of libev and also	228	Return the set of all backends compiled into this binary of libev and
219	recommended for this platform. This set is often smaller than the one	229	also recommended for this platform, meaning it will work for most file
		230	descriptor types. This set is often smaller than the one returned by
220	returned by C<ev_supported_backends>, as for example kqueue is broken on	231	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
221	most BSDs and will not be auto-detected unless you explicitly request it	232	and will not be auto-detected unless you explicitly request it (assuming
222	(assuming you know what you are doing). This is the set of backends that	233	you know what you are doing). This is the set of backends that libev will
223	libev will probe for if you specify no backends explicitly.	234	probe for if you specify no backends explicitly.
224		235
225	=item unsigned int ev_embeddable_backends ()	236	=item unsigned int ev_embeddable_backends ()
226		237
227	Returns the set of backends that are embeddable in other event loops. This	238	Returns the set of backends that are embeddable in other event loops. This
228	is the theoretical, all-platform, value. To find which backends	239	value is platform-specific but can include backends not available on the
229	might be supported on the current system, you would need to look at	240	current system. To find which embeddable backends might be supported on
230	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	241	the current system, you would need to look at C<ev_embeddable_backends ()
231	recommended ones.	242	& ev_supported_backends ()>, likewise for recommended ones.
232		243
233	See the description of C<ev_embed> watchers for more info.	244	See the description of C<ev_embed> watchers for more info.
234		245
235	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]	246	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]
236		247
…		…
290	...	301	...
291	ev_set_syserr_cb (fatal_error);	302	ev_set_syserr_cb (fatal_error);
292		303
293	=back	304	=back
294		305
295	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	306	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
296		307
297	An event loop is described by a C<struct ev_loop *> (the C<struct>	308	An event loop is described by a C<struct ev_loop *> (the C<struct> is
298	is I<not> optional in this case, as there is also an C<ev_loop>	309	I<not> optional in this case unless libev 3 compatibility is disabled, as
299	I<function>).	310	libev 3 had an C<ev_loop> function colliding with the struct name).
300		311
301	The library knows two types of such loops, the I<default> loop, which	312	The library knows two types of such loops, the I<default> loop, which
302	supports signals and child events, and dynamically created loops which do	313	supports child process events, and dynamically created event loops which
303	not.	314	do not.
304		315
305	=over 4	316	=over 4
306		317
307	=item struct ev_loop *ev_default_loop (unsigned int flags)	318	=item struct ev_loop *ev_default_loop (unsigned int flags)
308		319
309	This will initialise the default event loop if it hasn't been initialised	320	This returns the "default" event loop object, which is what you should
310	yet and return it. If the default loop could not be initialised, returns	321	normally use when you just need "the event loop". Event loop objects and
311	false. If it already was initialised it simply returns it (and ignores the	322	the C<flags> parameter are described in more detail in the entry for
312	flags. If that is troubling you, check C<ev_backend ()> afterwards).	323	C<ev_loop_new>.
		324
		325	If the default loop is already initialised then this function simply
		326	returns it (and ignores the flags. If that is troubling you, check
		327	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		328	flags, which should almost always be C<0>, unless the caller is also the
		329	one calling C<ev_run> or otherwise qualifies as "the main program".
313		330
314	If you don't know what event loop to use, use the one returned from this	331	If you don't know what event loop to use, use the one returned from this
315	function.	332	function (or via the C<EV_DEFAULT> macro).
316		333
317	Note that this function is I<not> thread-safe, so if you want to use it	334	Note that this function is I<not> thread-safe, so if you want to use it
318	from multiple threads, you have to lock (note also that this is unlikely,	335	from multiple threads, you have to employ some kind of mutex (note also
319	as loops cannot be shared easily between threads anyway).	336	that this case is unlikely, as loops cannot be shared easily between
		337	threads anyway).
320		338
321	The default loop is the only loop that can handle C<ev_signal> and	339	The default loop is the only loop that can handle C<ev_child> watchers,
322	C<ev_child> watchers, and to do this, it always registers a handler	340	and to do this, it always registers a handler for C<SIGCHLD>. If this is
323	for C<SIGCHLD>. If this is a problem for your application you can either	341	a problem for your application you can either create a dynamic loop with
324	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	342	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
325	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	343	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
326	C<ev_default_init>.	344
		345	Example: This is the most typical usage.
		346
		347	if (!ev_default_loop (0))
		348	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		349
		350	Example: Restrict libev to the select and poll backends, and do not allow
		351	environment settings to be taken into account:
		352
		353	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
		354
		355	=item struct ev_loop *ev_loop_new (unsigned int flags)
		356
		357	This will create and initialise a new event loop object. If the loop
		358	could not be initialised, returns false.
		359
		360	Note that this function I<is> thread-safe, and one common way to use
		361	libev with threads is indeed to create one loop per thread, and using the
		362	default loop in the "main" or "initial" thread.
327		363
328	The flags argument can be used to specify special behaviour or specific	364	The flags argument can be used to specify special behaviour or specific
329	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	365	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
330		366
331	The following flags are supported:	367	The following flags are supported:
…		…
427	epoll scales either O(1) or O(active_fds).	463	epoll scales either O(1) or O(active_fds).
428		464
429	The epoll mechanism deserves honorable mention as the most misdesigned	465	The epoll mechanism deserves honorable mention as the most misdesigned
430	of the more advanced event mechanisms: mere annoyances include silently	466	of the more advanced event mechanisms: mere annoyances include silently
431	dropping file descriptors, requiring a system call per change per file	467	dropping file descriptors, requiring a system call per change per file
432	descriptor (and unnecessary guessing of parameters), problems with dup and	468	descriptor (and unnecessary guessing of parameters), problems with dup,
		469	returning before the timeout value requiring additional iterations and so
433	so on. The biggest issue is fork races, however - if a program forks then	470	on. The biggest issue is fork races, however - if a program forks then
434	I<both> parent and child process have to recreate the epoll set, which can	471	I<both> parent and child process have to recreate the epoll set, which can
435	take considerable time (one syscall per file descriptor) and is of course	472	take considerable time (one syscall per file descriptor) and is of course
436	hard to detect.	473	hard to detect.
437		474
438	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but	475	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but
439	of course I<doesn't>, and epoll just loves to report events for totally	476	of course I<doesn't>, and epoll just loves to report events for totally
440	I<different> file descriptors (even already closed ones, so one cannot	477	I<different> file descriptors (even already closed ones, so one cannot
441	even remove them from the set) than registered in the set (especially	478	even remove them from the set) than registered in the set (especially
442	on SMP systems). Libev tries to counter these spurious notifications by	479	on SMP systems). Libev tries to counter these spurious notifications by
443	employing an additional generation counter and comparing that against the	480	employing an additional generation counter and comparing that against the
444	events to filter out spurious ones, recreating the set when required.	481	events to filter out spurious ones, recreating the set when required. Last
		482	not least, it also refuses to work with some file descriptors which work
		483	perfectly fine with C<select> (files, many character devices...).
445		484
446	While stopping, setting and starting an I/O watcher in the same iteration	485	While stopping, setting and starting an I/O watcher in the same iteration
447	will result in some caching, there is still a system call per such	486	will result in some caching, there is still a system call per such
448	incident (because the same I<file descriptor> could point to a different	487	incident (because the same I<file descriptor> could point to a different
449	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	488	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
547	If one or more of the backend flags are or'ed into the flags value,	586	If one or more of the backend flags are or'ed into the flags value,
548	then only these backends will be tried (in the reverse order as listed	587	then only these backends will be tried (in the reverse order as listed
549	here). If none are specified, all backends in C<ev_recommended_backends	588	here). If none are specified, all backends in C<ev_recommended_backends
550	()> will be tried.	589	()> will be tried.
551		590
552	Example: This is the most typical usage.
553
554	if (!ev_default_loop (0))
555	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
556
557	Example: Restrict libev to the select and poll backends, and do not allow
558	environment settings to be taken into account:
559
560	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
561
562	Example: Use whatever libev has to offer, but make sure that kqueue is
563	used if available (warning, breaks stuff, best use only with your own
564	private event loop and only if you know the OS supports your types of
565	fds):
566
567	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);
568
569	=item struct ev_loop *ev_loop_new (unsigned int flags)
570
571	Similar to C<ev_default_loop>, but always creates a new event loop that is
572	always distinct from the default loop.
573
574	Note that this function I<is> thread-safe, and one common way to use
575	libev with threads is indeed to create one loop per thread, and using the
576	default loop in the "main" or "initial" thread.
577
578	Example: Try to create a event loop that uses epoll and nothing else.	591	Example: Try to create a event loop that uses epoll and nothing else.
579		592
580	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	593	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
581	if (!epoller)	594	if (!epoller)
582	fatal ("no epoll found here, maybe it hides under your chair");	595	fatal ("no epoll found here, maybe it hides under your chair");
583		596
		597	Example: Use whatever libev has to offer, but make sure that kqueue is
		598	used if available.
		599
		600	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () \| EVBACKEND_KQUEUE);
		601
584	=item ev_default_destroy ()	602	=item ev_loop_destroy (loop)
585		603
586	Destroys the default loop (frees all memory and kernel state etc.). None	604	Destroys an event loop object (frees all memory and kernel state
587	of the active event watchers will be stopped in the normal sense, so	605	etc.). None of the active event watchers will be stopped in the normal
588	e.g. C<ev_is_active> might still return true. It is your responsibility to	606	sense, so e.g. C<ev_is_active> might still return true. It is your
589	either stop all watchers cleanly yourself I<before> calling this function,	607	responsibility to either stop all watchers cleanly yourself I<before>
590	or cope with the fact afterwards (which is usually the easiest thing, you	608	calling this function, or cope with the fact afterwards (which is usually
591	can just ignore the watchers and/or C<free ()> them for example).	609	the easiest thing, you can just ignore the watchers and/or C<free ()> them
		610	for example).
592		611
593	Note that certain global state, such as signal state (and installed signal	612	Note that certain global state, such as signal state (and installed signal
594	handlers), will not be freed by this function, and related watchers (such	613	handlers), will not be freed by this function, and related watchers (such
595	as signal and child watchers) would need to be stopped manually.	614	as signal and child watchers) would need to be stopped manually.
596		615
597	In general it is not advisable to call this function except in the	616	This function is normally used on loop objects allocated by
598	rare occasion where you really need to free e.g. the signal handling	617	C<ev_loop_new>, but it can also be used on the default loop returned by
		618	C<ev_default_loop>, in which case it is not thread-safe.
		619
		620	Note that it is not advisable to call this function on the default loop
		621	except in the rare occasion where you really need to free it's resources.
599	pipe fds. If you need dynamically allocated loops it is better to use	622	If you need dynamically allocated loops it is better to use C<ev_loop_new>
600	C<ev_loop_new> and C<ev_loop_destroy>.	623	and C<ev_loop_destroy>.
601		624
602	=item ev_loop_destroy (loop)	625	=item ev_loop_fork (loop)
603		626
604	Like C<ev_default_destroy>, but destroys an event loop created by an
605	earlier call to C<ev_loop_new>.
606
607	=item ev_default_fork ()
608
609	This function sets a flag that causes subsequent C<ev_loop> iterations	627	This function sets a flag that causes subsequent C<ev_run> iterations to
610	to reinitialise the kernel state for backends that have one. Despite the	628	reinitialise the kernel state for backends that have one. Despite the
611	name, you can call it anytime, but it makes most sense after forking, in	629	name, you can call it anytime, but it makes most sense after forking, in
612	the child process (or both child and parent, but that again makes little	630	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
613	sense). You I<must> call it in the child before using any of the libev	631	child before resuming or calling C<ev_run>.
614	functions, and it will only take effect at the next C<ev_loop> iteration.
615		632
616	Again, you I<have> to call it on I<any> loop that you want to re-use after	633	Again, you I<have> to call it on I<any> loop that you want to re-use after
617	a fork, I<even if you do not plan to use the loop in the parent>. This is	634	a fork, I<even if you do not plan to use the loop in the parent>. This is
618	because some kernel interfaces cough I<kqueue> cough do funny things	635	because some kernel interfaces cough I<kqueue> cough do funny things
619	during fork.	636	during fork.
620		637
621	On the other hand, you only need to call this function in the child	638	On the other hand, you only need to call this function in the child
622	process if and only if you want to use the event loop in the child. If you	639	process if and only if you want to use the event loop in the child. If
623	just fork+exec or create a new loop in the child, you don't have to call	640	you just fork+exec or create a new loop in the child, you don't have to
624	it at all.	641	call it at all (in fact, C<epoll> is so badly broken that it makes a
		642	difference, but libev will usually detect this case on its own and do a
		643	costly reset of the backend).
625		644
626	The function itself is quite fast and it's usually not a problem to call	645	The function itself is quite fast and it's usually not a problem to call
627	it just in case after a fork. To make this easy, the function will fit in	646	it just in case after a fork.
628	quite nicely into a call to C<pthread_atfork>:
629		647
		648	Example: Automate calling C<ev_loop_fork> on the default loop when
		649	using pthreads.
		650
		651	static void
		652	post_fork_child (void)
		653	{
		654	ev_loop_fork (EV_DEFAULT);
		655	}
		656
		657	...
630	pthread_atfork (0, 0, ev_default_fork);	658	pthread_atfork (0, 0, post_fork_child);
631
632	=item ev_loop_fork (loop)
633
634	Like C<ev_default_fork>, but acts on an event loop created by
635	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
636	after fork that you want to re-use in the child, and how you keep track of
637	them is entirely your own problem.
638		659
639	=item int ev_is_default_loop (loop)	660	=item int ev_is_default_loop (loop)
640		661
641	Returns true when the given loop is, in fact, the default loop, and false	662	Returns true when the given loop is, in fact, the default loop, and false
642	otherwise.	663	otherwise.
643		664
644	=item unsigned int ev_iteration (loop)	665	=item unsigned int ev_iteration (loop)
645		666
646	Returns the current iteration count for the loop, which is identical to	667	Returns the current iteration count for the event loop, which is identical
647	the number of times libev did poll for new events. It starts at C<0> and	668	to the number of times libev did poll for new events. It starts at C<0>
648	happily wraps around with enough iterations.	669	and happily wraps around with enough iterations.
649		670
650	This value can sometimes be useful as a generation counter of sorts (it	671	This value can sometimes be useful as a generation counter of sorts (it
651	"ticks" the number of loop iterations), as it roughly corresponds with	672	"ticks" the number of loop iterations), as it roughly corresponds with
652	C<ev_prepare> and C<ev_check> calls - and is incremented between the	673	C<ev_prepare> and C<ev_check> calls - and is incremented between the
653	prepare and check phases.	674	prepare and check phases.
654		675
655	=item unsigned int ev_depth (loop)	676	=item unsigned int ev_depth (loop)
656		677
657	Returns the number of times C<ev_loop> was entered minus the number of	678	Returns the number of times C<ev_run> was entered minus the number of
658	times C<ev_loop> was exited, in other words, the recursion depth.	679	times C<ev_run> was exited, in other words, the recursion depth.
659		680
660	Outside C<ev_loop>, this number is zero. In a callback, this number is	681	Outside C<ev_run>, this number is zero. In a callback, this number is
661	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	682	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
662	in which case it is higher.	683	in which case it is higher.
663		684
664	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	685	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
665	etc.), doesn't count as "exit" - consider this as a hint to avoid such	686	etc.), doesn't count as "exit" - consider this as a hint to avoid such
666	ungentleman behaviour unless it's really convenient.	687	ungentleman-like behaviour unless it's really convenient.
667		688
668	=item unsigned int ev_backend (loop)	689	=item unsigned int ev_backend (loop)
669		690
670	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	691	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
671	use.	692	use.
…		…
680		701
681	=item ev_now_update (loop)	702	=item ev_now_update (loop)
682		703
683	Establishes the current time by querying the kernel, updating the time	704	Establishes the current time by querying the kernel, updating the time
684	returned by C<ev_now ()> in the progress. This is a costly operation and	705	returned by C<ev_now ()> in the progress. This is a costly operation and
685	is usually done automatically within C<ev_loop ()>.	706	is usually done automatically within C<ev_run ()>.
686		707
687	This function is rarely useful, but when some event callback runs for a	708	This function is rarely useful, but when some event callback runs for a
688	very long time without entering the event loop, updating libev's idea of	709	very long time without entering the event loop, updating libev's idea of
689	the current time is a good idea.	710	the current time is a good idea.
690		711
…		…
692		713
693	=item ev_suspend (loop)	714	=item ev_suspend (loop)
694		715
695	=item ev_resume (loop)	716	=item ev_resume (loop)
696		717
697	These two functions suspend and resume a loop, for use when the loop is	718	These two functions suspend and resume an event loop, for use when the
698	not used for a while and timeouts should not be processed.	719	loop is not used for a while and timeouts should not be processed.
699		720
700	A typical use case would be an interactive program such as a game: When	721	A typical use case would be an interactive program such as a game: When
701	the user presses C<^Z> to suspend the game and resumes it an hour later it	722	the user presses C<^Z> to suspend the game and resumes it an hour later it
702	would be best to handle timeouts as if no time had actually passed while	723	would be best to handle timeouts as if no time had actually passed while
703	the program was suspended. This can be achieved by calling C<ev_suspend>	724	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
714	without a previous call to C<ev_suspend>.	735	without a previous call to C<ev_suspend>.
715		736
716	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	737	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
717	event loop time (see C<ev_now_update>).	738	event loop time (see C<ev_now_update>).
718		739
719	=item ev_loop (loop, int flags)	740	=item ev_run (loop, int flags)
720		741
721	Finally, this is it, the event handler. This function usually is called	742	Finally, this is it, the event handler. This function usually is called
722	after you have initialised all your watchers and you want to start	743	after you have initialised all your watchers and you want to start
723	handling events.	744	handling events. It will ask the operating system for any new events, call
		745	the watcher callbacks, an then repeat the whole process indefinitely: This
		746	is why event loops are called I<loops>.
724		747
725	If the flags argument is specified as C<0>, it will not return until	748	If the flags argument is specified as C<0>, it will keep handling events
726	either no event watchers are active anymore or C<ev_unloop> was called.	749	until either no event watchers are active anymore or C<ev_break> was
		750	called.
727		751
728	Please note that an explicit C<ev_unloop> is usually better than	752	Please note that an explicit C<ev_break> is usually better than
729	relying on all watchers to be stopped when deciding when a program has	753	relying on all watchers to be stopped when deciding when a program has
730	finished (especially in interactive programs), but having a program	754	finished (especially in interactive programs), but having a program
731	that automatically loops as long as it has to and no longer by virtue	755	that automatically loops as long as it has to and no longer by virtue
732	of relying on its watchers stopping correctly, that is truly a thing of	756	of relying on its watchers stopping correctly, that is truly a thing of
733	beauty.	757	beauty.
734		758
735	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	759	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
736	those events and any already outstanding ones, but will not block your	760	those events and any already outstanding ones, but will not wait and
737	process in case there are no events and will return after one iteration of	761	block your process in case there are no events and will return after one
738	the loop.	762	iteration of the loop. This is sometimes useful to poll and handle new
		763	events while doing lengthy calculations, to keep the program responsive.
739		764
740	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	765	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
741	necessary) and will handle those and any already outstanding ones. It	766	necessary) and will handle those and any already outstanding ones. It
742	will block your process until at least one new event arrives (which could	767	will block your process until at least one new event arrives (which could
743	be an event internal to libev itself, so there is no guarantee that a	768	be an event internal to libev itself, so there is no guarantee that a
744	user-registered callback will be called), and will return after one	769	user-registered callback will be called), and will return after one
745	iteration of the loop.	770	iteration of the loop.
746		771
747	This is useful if you are waiting for some external event in conjunction	772	This is useful if you are waiting for some external event in conjunction
748	with something not expressible using other libev watchers (i.e. "roll your	773	with something not expressible using other libev watchers (i.e. "roll your
749	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	774	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
750	usually a better approach for this kind of thing.	775	usually a better approach for this kind of thing.
751		776
752	Here are the gory details of what C<ev_loop> does:	777	Here are the gory details of what C<ev_run> does:
753		778
		779	- Increment loop depth.
		780	- Reset the ev_break status.
754	- Before the first iteration, call any pending watchers.	781	- Before the first iteration, call any pending watchers.
		782	LOOP:
755	* If EVFLAG_FORKCHECK was used, check for a fork.	783	- If EVFLAG_FORKCHECK was used, check for a fork.
756	- If a fork was detected (by any means), queue and call all fork watchers.	784	- If a fork was detected (by any means), queue and call all fork watchers.
757	- Queue and call all prepare watchers.	785	- Queue and call all prepare watchers.
		786	- If ev_break was called, goto FINISH.
758	- If we have been forked, detach and recreate the kernel state	787	- If we have been forked, detach and recreate the kernel state
759	as to not disturb the other process.	788	as to not disturb the other process.
760	- Update the kernel state with all outstanding changes.	789	- Update the kernel state with all outstanding changes.
761	- Update the "event loop time" (ev_now ()).	790	- Update the "event loop time" (ev_now ()).
762	- Calculate for how long to sleep or block, if at all	791	- Calculate for how long to sleep or block, if at all
763	(active idle watchers, EVLOOP_NONBLOCK or not having	792	(active idle watchers, EVRUN_NOWAIT or not having
764	any active watchers at all will result in not sleeping).	793	any active watchers at all will result in not sleeping).
765	- Sleep if the I/O and timer collect interval say so.	794	- Sleep if the I/O and timer collect interval say so.
		795	- Increment loop iteration counter.
766	- Block the process, waiting for any events.	796	- Block the process, waiting for any events.
767	- Queue all outstanding I/O (fd) events.	797	- Queue all outstanding I/O (fd) events.
768	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	798	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
769	- Queue all expired timers.	799	- Queue all expired timers.
770	- Queue all expired periodics.	800	- Queue all expired periodics.
771	- Unless any events are pending now, queue all idle watchers.	801	- Queue all idle watchers with priority higher than that of pending events.
772	- Queue all check watchers.	802	- Queue all check watchers.
773	- Call all queued watchers in reverse order (i.e. check watchers first).	803	- Call all queued watchers in reverse order (i.e. check watchers first).
774	Signals and child watchers are implemented as I/O watchers, and will	804	Signals and child watchers are implemented as I/O watchers, and will
775	be handled here by queueing them when their watcher gets executed.	805	be handled here by queueing them when their watcher gets executed.
776	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	806	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
777	were used, or there are no active watchers, return, otherwise	807	were used, or there are no active watchers, goto FINISH, otherwise
778	continue with step *.	808	continue with step LOOP.
		809	FINISH:
		810	- Reset the ev_break status iff it was EVBREAK_ONE.
		811	- Decrement the loop depth.
		812	- Return.
779		813
780	Example: Queue some jobs and then loop until no events are outstanding	814	Example: Queue some jobs and then loop until no events are outstanding
781	anymore.	815	anymore.
782		816
783	... queue jobs here, make sure they register event watchers as long	817	... queue jobs here, make sure they register event watchers as long
784	... as they still have work to do (even an idle watcher will do..)	818	... as they still have work to do (even an idle watcher will do..)
785	ev_loop (my_loop, 0);	819	ev_run (my_loop, 0);
786	... jobs done or somebody called unloop. yeah!	820	... jobs done or somebody called unloop. yeah!
787		821
788	=item ev_unloop (loop, how)	822	=item ev_break (loop, how)
789		823
790	Can be used to make a call to C<ev_loop> return early (but only after it	824	Can be used to make a call to C<ev_run> return early (but only after it
791	has processed all outstanding events). The C<how> argument must be either	825	has processed all outstanding events). The C<how> argument must be either
792	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	826	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
793	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	827	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
794		828
795	This "unloop state" will be cleared when entering C<ev_loop> again.	829	This "break state" will be cleared when entering C<ev_run> again.
796		830
797	It is safe to call C<ev_unloop> from outside any C<ev_loop> calls.	831	It is safe to call C<ev_break> from outside any C<ev_run> calls, too.
798		832
799	=item ev_ref (loop)	833	=item ev_ref (loop)
800		834
801	=item ev_unref (loop)	835	=item ev_unref (loop)
802		836
803	Ref/unref can be used to add or remove a reference count on the event	837	Ref/unref can be used to add or remove a reference count on the event
804	loop: Every watcher keeps one reference, and as long as the reference	838	loop: Every watcher keeps one reference, and as long as the reference
805	count is nonzero, C<ev_loop> will not return on its own.	839	count is nonzero, C<ev_run> will not return on its own.
806		840
807	This is useful when you have a watcher that you never intend to	841	This is useful when you have a watcher that you never intend to
808	unregister, but that nevertheless should not keep C<ev_loop> from	842	unregister, but that nevertheless should not keep C<ev_run> from
809	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>	843	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
810	before stopping it.	844	before stopping it.
811		845
812	As an example, libev itself uses this for its internal signal pipe: It	846	As an example, libev itself uses this for its internal signal pipe: It
813	is not visible to the libev user and should not keep C<ev_loop> from	847	is not visible to the libev user and should not keep C<ev_run> from
814	exiting if no event watchers registered by it are active. It is also an	848	exiting if no event watchers registered by it are active. It is also an
815	excellent way to do this for generic recurring timers or from within	849	excellent way to do this for generic recurring timers or from within
816	third-party libraries. Just remember to I<unref after start> and I<ref	850	third-party libraries. Just remember to I<unref after start> and I<ref
817	before stop> (but only if the watcher wasn't active before, or was active	851	before stop> (but only if the watcher wasn't active before, or was active
818	before, respectively. Note also that libev might stop watchers itself	852	before, respectively. Note also that libev might stop watchers itself
819	(e.g. non-repeating timers) in which case you have to C<ev_ref>	853	(e.g. non-repeating timers) in which case you have to C<ev_ref>
820	in the callback).	854	in the callback).
821		855
822	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	856	Example: Create a signal watcher, but keep it from keeping C<ev_run>
823	running when nothing else is active.	857	running when nothing else is active.
824		858
825	ev_signal exitsig;	859	ev_signal exitsig;
826	ev_signal_init (&exitsig, sig_cb, SIGINT);	860	ev_signal_init (&exitsig, sig_cb, SIGINT);
827	ev_signal_start (loop, &exitsig);	861	ev_signal_start (loop, &exitsig);
…		…
890	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	924	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
891		925
892	=item ev_invoke_pending (loop)	926	=item ev_invoke_pending (loop)
893		927
894	This call will simply invoke all pending watchers while resetting their	928	This call will simply invoke all pending watchers while resetting their
895	pending state. Normally, C<ev_loop> does this automatically when required,	929	pending state. Normally, C<ev_run> does this automatically when required,
896	but when overriding the invoke callback this call comes handy.	930	but when overriding the invoke callback this call comes handy. This
		931	function can be invoked from a watcher - this can be useful for example
		932	when you want to do some lengthy calculation and want to pass further
		933	event handling to another thread (you still have to make sure only one
		934	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
897		935
898	=item int ev_pending_count (loop)	936	=item int ev_pending_count (loop)
899		937
900	Returns the number of pending watchers - zero indicates that no watchers	938	Returns the number of pending watchers - zero indicates that no watchers
901	are pending.	939	are pending.
902		940
903	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	941	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
904		942
905	This overrides the invoke pending functionality of the loop: Instead of	943	This overrides the invoke pending functionality of the loop: Instead of
906	invoking all pending watchers when there are any, C<ev_loop> will call	944	invoking all pending watchers when there are any, C<ev_run> will call
907	this callback instead. This is useful, for example, when you want to	945	this callback instead. This is useful, for example, when you want to
908	invoke the actual watchers inside another context (another thread etc.).	946	invoke the actual watchers inside another context (another thread etc.).
909		947
910	If you want to reset the callback, use C<ev_invoke_pending> as new	948	If you want to reset the callback, use C<ev_invoke_pending> as new
911	callback.	949	callback.
…		…
914		952
915	Sometimes you want to share the same loop between multiple threads. This	953	Sometimes you want to share the same loop between multiple threads. This
916	can be done relatively simply by putting mutex_lock/unlock calls around	954	can be done relatively simply by putting mutex_lock/unlock calls around
917	each call to a libev function.	955	each call to a libev function.
918		956
919	However, C<ev_loop> can run an indefinite time, so it is not feasible to	957	However, C<ev_run> can run an indefinite time, so it is not feasible
920	wait for it to return. One way around this is to wake up the loop via	958	to wait for it to return. One way around this is to wake up the event
921	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	959	loop via C<ev_break> and C<av_async_send>, another way is to set these
922	and I<acquire> callbacks on the loop.	960	I<release> and I<acquire> callbacks on the loop.
923		961
924	When set, then C<release> will be called just before the thread is	962	When set, then C<release> will be called just before the thread is
925	suspended waiting for new events, and C<acquire> is called just	963	suspended waiting for new events, and C<acquire> is called just
926	afterwards.	964	afterwards.
927		965
…		…
930		968
931	While event loop modifications are allowed between invocations of	969	While event loop modifications are allowed between invocations of
932	C<release> and C<acquire> (that's their only purpose after all), no	970	C<release> and C<acquire> (that's their only purpose after all), no
933	modifications done will affect the event loop, i.e. adding watchers will	971	modifications done will affect the event loop, i.e. adding watchers will
934	have no effect on the set of file descriptors being watched, or the time	972	have no effect on the set of file descriptors being watched, or the time
935	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	973	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
936	to take note of any changes you made.	974	to take note of any changes you made.
937		975
938	In theory, threads executing C<ev_loop> will be async-cancel safe between	976	In theory, threads executing C<ev_run> will be async-cancel safe between
939	invocations of C<release> and C<acquire>.	977	invocations of C<release> and C<acquire>.
940		978
941	See also the locking example in the C<THREADS> section later in this	979	See also the locking example in the C<THREADS> section later in this
942	document.	980	document.
943		981
…		…
952	These two functions can be used to associate arbitrary data with a loop,	990	These two functions can be used to associate arbitrary data with a loop,
953	and are intended solely for the C<invoke_pending_cb>, C<release> and	991	and are intended solely for the C<invoke_pending_cb>, C<release> and
954	C<acquire> callbacks described above, but of course can be (ab-)used for	992	C<acquire> callbacks described above, but of course can be (ab-)used for
955	any other purpose as well.	993	any other purpose as well.
956		994
957	=item ev_loop_verify (loop)	995	=item ev_verify (loop)
958		996
959	This function only does something when C<EV_VERIFY> support has been	997	This function only does something when C<EV_VERIFY> support has been
960	compiled in, which is the default for non-minimal builds. It tries to go	998	compiled in, which is the default for non-minimal builds. It tries to go
961	through all internal structures and checks them for validity. If anything	999	through all internal structures and checks them for validity. If anything
962	is found to be inconsistent, it will print an error message to standard	1000	is found to be inconsistent, it will print an error message to standard
…		…
973		1011
974	In the following description, uppercase C<TYPE> in names stands for the	1012	In the following description, uppercase C<TYPE> in names stands for the
975	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1013	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
976	watchers and C<ev_io_start> for I/O watchers.	1014	watchers and C<ev_io_start> for I/O watchers.
977		1015
978	A watcher is a structure that you create and register to record your	1016	A watcher is an opaque structure that you allocate and register to record
979	interest in some event. For instance, if you want to wait for STDIN to	1017	your interest in some event. To make a concrete example, imagine you want
980	become readable, you would create an C<ev_io> watcher for that:	1018	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1019	for that:
981		1020
982	static void my_cb (struct ev_loop loop, ev_io w, int revents)	1021	static void my_cb (struct ev_loop loop, ev_io w, int revents)
983	{	1022	{
984	ev_io_stop (w);	1023	ev_io_stop (w);
985	ev_unloop (loop, EVUNLOOP_ALL);	1024	ev_break (loop, EVBREAK_ALL);
986	}	1025	}
987		1026
988	struct ev_loop *loop = ev_default_loop (0);	1027	struct ev_loop *loop = ev_default_loop (0);
989		1028
990	ev_io stdin_watcher;	1029	ev_io stdin_watcher;
991		1030
992	ev_init (&stdin_watcher, my_cb);	1031	ev_init (&stdin_watcher, my_cb);
993	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1032	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
994	ev_io_start (loop, &stdin_watcher);	1033	ev_io_start (loop, &stdin_watcher);
995		1034
996	ev_loop (loop, 0);	1035	ev_run (loop, 0);
997		1036
998	As you can see, you are responsible for allocating the memory for your	1037	As you can see, you are responsible for allocating the memory for your
999	watcher structures (and it is I<usually> a bad idea to do this on the	1038	watcher structures (and it is I<usually> a bad idea to do this on the
1000	stack).	1039	stack).
1001		1040
1002	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1041	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1003	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1042	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1004		1043
1005	Each watcher structure must be initialised by a call to C<ev_init	1044	Each watcher structure must be initialised by a call to C<ev_init (watcher
1006	(watcher *, callback)>, which expects a callback to be provided. This	1045	*, callback)>, which expects a callback to be provided. This callback is
1007	callback gets invoked each time the event occurs (or, in the case of I/O	1046	invoked each time the event occurs (or, in the case of I/O watchers, each
1008	watchers, each time the event loop detects that the file descriptor given	1047	time the event loop detects that the file descriptor given is readable
1009	is readable and/or writable).	1048	and/or writable).
1010		1049
1011	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1050	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1012	macro to configure it, with arguments specific to the watcher type. There	1051	macro to configure it, with arguments specific to the watcher type. There
1013	is also a macro to combine initialisation and setting in one call: C<<	1052	is also a macro to combine initialisation and setting in one call: C<<
1014	ev_TYPE_init (watcher *, callback, ...) >>.	1053	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1065		1104
1066	=item C<EV_PREPARE>	1105	=item C<EV_PREPARE>
1067		1106
1068	=item C<EV_CHECK>	1107	=item C<EV_CHECK>
1069		1108
1070	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1109	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1071	to gather new events, and all C<ev_check> watchers are invoked just after	1110	to gather new events, and all C<ev_check> watchers are invoked just after
1072	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1111	C<ev_run> has gathered them, but before it invokes any callbacks for any
1073	received events. Callbacks of both watcher types can start and stop as	1112	received events. Callbacks of both watcher types can start and stop as
1074	many watchers as they want, and all of them will be taken into account	1113	many watchers as they want, and all of them will be taken into account
1075	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1114	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1076	C<ev_loop> from blocking).	1115	C<ev_run> from blocking).
1077		1116
1078	=item C<EV_EMBED>	1117	=item C<EV_EMBED>
1079		1118
1080	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1119	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1081		1120
1082	=item C<EV_FORK>	1121	=item C<EV_FORK>
1083		1122
1084	The event loop has been resumed in the child process after fork (see	1123	The event loop has been resumed in the child process after fork (see
1085	C<ev_fork>).	1124	C<ev_fork>).
		1125
		1126	=item C<EV_CLEANUP>
		1127
		1128	The event loop is about to be destroyed (see C<ev_cleanup>).
1086		1129
1087	=item C<EV_ASYNC>	1130	=item C<EV_ASYNC>
1088		1131
1089	The given async watcher has been asynchronously notified (see C<ev_async>).	1132	The given async watcher has been asynchronously notified (see C<ev_async>).
1090		1133
…		…
1262		1305
1263	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related	1306	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
1264	functions that do not need a watcher.	1307	functions that do not need a watcher.
1265		1308
1266	=back	1309	=back
1267
1268		1310
1269	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1311	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
1270		1312
1271	Each watcher has, by default, a member C<void *data> that you can change	1313	Each watcher has, by default, a member C<void *data> that you can change
1272	and read at any time: libev will completely ignore it. This can be used	1314	and read at any time: libev will completely ignore it. This can be used
…		…
1328	t2_cb (EV_P_ ev_timer *w, int revents)	1370	t2_cb (EV_P_ ev_timer *w, int revents)
1329	{	1371	{
1330	struct my_biggy big = (struct my_biggy *)	1372	struct my_biggy big = (struct my_biggy *)
1331	(((char *)w) - offsetof (struct my_biggy, t2));	1373	(((char *)w) - offsetof (struct my_biggy, t2));
1332	}	1374	}
		1375
		1376	=head2 WATCHER STATES
		1377
		1378	There are various watcher states mentioned throughout this manual -
		1379	active, pending and so on. In this section these states and the rules to
		1380	transition between them will be described in more detail - and while these
		1381	rules might look complicated, they usually do "the right thing".
		1382
		1383	=over 4
		1384
		1385	=item initialiased
		1386
		1387	Before a watcher can be registered with the event looop it has to be
		1388	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1389	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1390
		1391	In this state it is simply some block of memory that is suitable for use
		1392	in an event loop. It can be moved around, freed, reused etc. at will.
		1393
		1394	=item started/running/active
		1395
		1396	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1397	property of the event loop, and is actively waiting for events. While in
		1398	this state it cannot be accessed (except in a few documented ways), moved,
		1399	freed or anything else - the only legal thing is to keep a pointer to it,
		1400	and call libev functions on it that are documented to work on active watchers.
		1401
		1402	=item pending
		1403
		1404	If a watcher is active and libev determines that an event it is interested
		1405	in has occurred (such as a timer expiring), it will become pending. It will
		1406	stay in this pending state until either it is stopped or its callback is
		1407	about to be invoked, so it is not normally pending inside the watcher
		1408	callback.
		1409
		1410	The watcher might or might not be active while it is pending (for example,
		1411	an expired non-repeating timer can be pending but no longer active). If it
		1412	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1413	but it is still property of the event loop at this time, so cannot be
		1414	moved, freed or reused. And if it is active the rules described in the
		1415	previous item still apply.
		1416
		1417	It is also possible to feed an event on a watcher that is not active (e.g.
		1418	via C<ev_feed_event>), in which case it becomes pending without being
		1419	active.
		1420
		1421	=item stopped
		1422
		1423	A watcher can be stopped implicitly by libev (in which case it might still
		1424	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1425	latter will clear any pending state the watcher might be in, regardless
		1426	of whether it was active or not, so stopping a watcher explicitly before
		1427	freeing it is often a good idea.
		1428
		1429	While stopped (and not pending) the watcher is essentially in the
		1430	initialised state, that is it can be reused, moved, modified in any way
		1431	you wish.
		1432
		1433	=back
1333		1434
1334	=head2 WATCHER PRIORITY MODELS	1435	=head2 WATCHER PRIORITY MODELS
1335		1436
1336	Many event loops support I<watcher priorities>, which are usually small	1437	Many event loops support I<watcher priorities>, which are usually small
1337	integers that influence the ordering of event callback invocation	1438	integers that influence the ordering of event callback invocation
…		…
1622	...	1723	...
1623	struct ev_loop *loop = ev_default_init (0);	1724	struct ev_loop *loop = ev_default_init (0);
1624	ev_io stdin_readable;	1725	ev_io stdin_readable;
1625	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1726	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1626	ev_io_start (loop, &stdin_readable);	1727	ev_io_start (loop, &stdin_readable);
1627	ev_loop (loop, 0);	1728	ev_run (loop, 0);
1628		1729
1629		1730
1630	=head2 C<ev_timer> - relative and optionally repeating timeouts	1731	=head2 C<ev_timer> - relative and optionally repeating timeouts
1631		1732
1632	Timer watchers are simple relative timers that generate an event after a	1733	Timer watchers are simple relative timers that generate an event after a
…		…
1641	The callback is guaranteed to be invoked only I<after> its timeout has	1742	The callback is guaranteed to be invoked only I<after> its timeout has
1642	passed (not I<at>, so on systems with very low-resolution clocks this	1743	passed (not I<at>, so on systems with very low-resolution clocks this
1643	might introduce a small delay). If multiple timers become ready during the	1744	might introduce a small delay). If multiple timers become ready during the
1644	same loop iteration then the ones with earlier time-out values are invoked	1745	same loop iteration then the ones with earlier time-out values are invoked
1645	before ones of the same priority with later time-out values (but this is	1746	before ones of the same priority with later time-out values (but this is
1646	no longer true when a callback calls C<ev_loop> recursively).	1747	no longer true when a callback calls C<ev_run> recursively).
1647		1748
1648	=head3 Be smart about timeouts	1749	=head3 Be smart about timeouts
1649		1750
1650	Many real-world problems involve some kind of timeout, usually for error	1751	Many real-world problems involve some kind of timeout, usually for error
1651	recovery. A typical example is an HTTP request - if the other side hangs,	1752	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1822		1923
1823	=head3 The special problem of time updates	1924	=head3 The special problem of time updates
1824		1925
1825	Establishing the current time is a costly operation (it usually takes at	1926	Establishing the current time is a costly operation (it usually takes at
1826	least two system calls): EV therefore updates its idea of the current	1927	least two system calls): EV therefore updates its idea of the current
1827	time only before and after C<ev_loop> collects new events, which causes a	1928	time only before and after C<ev_run> collects new events, which causes a
1828	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1929	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1829	lots of events in one iteration.	1930	lots of events in one iteration.
1830		1931
1831	The relative timeouts are calculated relative to the C<ev_now ()>	1932	The relative timeouts are calculated relative to the C<ev_now ()>
1832	time. This is usually the right thing as this timestamp refers to the time	1933	time. This is usually the right thing as this timestamp refers to the time
…		…
1949	}	2050	}
1950		2051
1951	ev_timer mytimer;	2052	ev_timer mytimer;
1952	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2053	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1953	ev_timer_again (&mytimer); /* start timer */	2054	ev_timer_again (&mytimer); /* start timer */
1954	ev_loop (loop, 0);	2055	ev_run (loop, 0);
1955		2056
1956	// and in some piece of code that gets executed on any "activity":	2057	// and in some piece of code that gets executed on any "activity":
1957	// reset the timeout to start ticking again at 10 seconds	2058	// reset the timeout to start ticking again at 10 seconds
1958	ev_timer_again (&mytimer);	2059	ev_timer_again (&mytimer);
1959		2060
…		…
1985		2086
1986	As with timers, the callback is guaranteed to be invoked only when the	2087	As with timers, the callback is guaranteed to be invoked only when the
1987	point in time where it is supposed to trigger has passed. If multiple	2088	point in time where it is supposed to trigger has passed. If multiple
1988	timers become ready during the same loop iteration then the ones with	2089	timers become ready during the same loop iteration then the ones with
1989	earlier time-out values are invoked before ones with later time-out values	2090	earlier time-out values are invoked before ones with later time-out values
1990	(but this is no longer true when a callback calls C<ev_loop> recursively).	2091	(but this is no longer true when a callback calls C<ev_run> recursively).
1991		2092
1992	=head3 Watcher-Specific Functions and Data Members	2093	=head3 Watcher-Specific Functions and Data Members
1993		2094
1994	=over 4	2095	=over 4
1995		2096
…		…
2233	Example: Try to exit cleanly on SIGINT.	2334	Example: Try to exit cleanly on SIGINT.
2234		2335
2235	static void	2336	static void
2236	sigint_cb (struct ev_loop loop, ev_signal w, int revents)	2337	sigint_cb (struct ev_loop loop, ev_signal w, int revents)
2237	{	2338	{
2238	ev_unloop (loop, EVUNLOOP_ALL);	2339	ev_break (loop, EVBREAK_ALL);
2239	}	2340	}
2240		2341
2241	ev_signal signal_watcher;	2342	ev_signal signal_watcher;
2242	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2343	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2243	ev_signal_start (loop, &signal_watcher);	2344	ev_signal_start (loop, &signal_watcher);
…		…
2629		2730
2630	Prepare and check watchers are usually (but not always) used in pairs:	2731	Prepare and check watchers are usually (but not always) used in pairs:
2631	prepare watchers get invoked before the process blocks and check watchers	2732	prepare watchers get invoked before the process blocks and check watchers
2632	afterwards.	2733	afterwards.
2633		2734
2634	You I<must not> call C<ev_loop> or similar functions that enter	2735	You I<must not> call C<ev_run> or similar functions that enter
2635	the current event loop from either C<ev_prepare> or C<ev_check>	2736	the current event loop from either C<ev_prepare> or C<ev_check>
2636	watchers. Other loops than the current one are fine, however. The	2737	watchers. Other loops than the current one are fine, however. The
2637	rationale behind this is that you do not need to check for recursion in	2738	rationale behind this is that you do not need to check for recursion in
2638	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2739	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2639	C<ev_check> so if you have one watcher of each kind they will always be	2740	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2807		2908
2808	if (timeout >= 0)	2909	if (timeout >= 0)
2809	// create/start timer	2910	// create/start timer
2810		2911
2811	// poll	2912	// poll
2812	ev_loop (EV_A_ 0);	2913	ev_run (EV_A_ 0);
2813		2914
2814	// stop timer again	2915	// stop timer again
2815	if (timeout >= 0)	2916	if (timeout >= 0)
2816	ev_timer_stop (EV_A_ &to);	2917	ev_timer_stop (EV_A_ &to);
2817		2918
…		…
2895	if you do not want that, you need to temporarily stop the embed watcher).	2996	if you do not want that, you need to temporarily stop the embed watcher).
2896		2997
2897	=item ev_embed_sweep (loop, ev_embed *)	2998	=item ev_embed_sweep (loop, ev_embed *)
2898		2999
2899	Make a single, non-blocking sweep over the embedded loop. This works	3000	Make a single, non-blocking sweep over the embedded loop. This works
2900	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	3001	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2901	appropriate way for embedded loops.	3002	appropriate way for embedded loops.
2902		3003
2903	=item struct ev_loop *other [read-only]	3004	=item struct ev_loop *other [read-only]
2904		3005
2905	The embedded event loop.	3006	The embedded event loop.
…		…
2991	disadvantage of having to use multiple event loops (which do not support	3092	disadvantage of having to use multiple event loops (which do not support
2992	signal watchers).	3093	signal watchers).
2993		3094
2994	When this is not possible, or you want to use the default loop for	3095	When this is not possible, or you want to use the default loop for
2995	other reasons, then in the process that wants to start "fresh", call	3096	other reasons, then in the process that wants to start "fresh", call
2996	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3097	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2997	the default loop will "orphan" (not stop) all registered watchers, so you	3098	Destroying the default loop will "orphan" (not stop) all registered
2998	have to be careful not to execute code that modifies those watchers. Note	3099	watchers, so you have to be careful not to execute code that modifies
2999	also that in that case, you have to re-register any signal watchers.	3100	those watchers. Note also that in that case, you have to re-register any
		3101	signal watchers.
3000		3102
3001	=head3 Watcher-Specific Functions and Data Members	3103	=head3 Watcher-Specific Functions and Data Members
3002		3104
3003	=over 4	3105	=over 4
3004		3106
3005	=item ev_fork_init (ev_signal *, callback)	3107	=item ev_fork_init (ev_fork *, callback)
3006		3108
3007	Initialises and configures the fork watcher - it has no parameters of any	3109	Initialises and configures the fork watcher - it has no parameters of any
3008	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,	3110	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3009	believe me.	3111	really.
3010		3112
3011	=back	3113	=back
3012		3114
3013		3115
		3116	=head2 C<ev_cleanup> - even the best things end
		3117
		3118	Cleanup watchers are called just before the event loop is being destroyed
		3119	by a call to C<ev_loop_destroy>.
		3120
		3121	While there is no guarantee that the event loop gets destroyed, cleanup
		3122	watchers provide a convenient method to install cleanup hooks for your
		3123	program, worker threads and so on - you just to make sure to destroy the
		3124	loop when you want them to be invoked.
		3125
		3126	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3127	all other watchers, they do not keep a reference to the event loop (which
		3128	makes a lot of sense if you think about it). Like all other watchers, you
		3129	can call libev functions in the callback, except C<ev_cleanup_start>.
		3130
		3131	=head3 Watcher-Specific Functions and Data Members
		3132
		3133	=over 4
		3134
		3135	=item ev_cleanup_init (ev_cleanup *, callback)
		3136
		3137	Initialises and configures the cleanup watcher - it has no parameters of
		3138	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3139	pointless, I assure you.
		3140
		3141	=back
		3142
		3143	Example: Register an atexit handler to destroy the default loop, so any
		3144	cleanup functions are called.
		3145
		3146	static void
		3147	program_exits (void)
		3148	{
		3149	ev_loop_destroy (EV_DEFAULT_UC);
		3150	}
		3151
		3152	...
		3153	atexit (program_exits);
		3154
		3155
3014	=head2 C<ev_async> - how to wake up an event loop	3156	=head2 C<ev_async> - how to wake up an event loop
3015		3157
3016	In general, you cannot use an C<ev_loop> from multiple threads or other	3158	In general, you cannot use an C<ev_run> from multiple threads or other
3017	asynchronous sources such as signal handlers (as opposed to multiple event	3159	asynchronous sources such as signal handlers (as opposed to multiple event
3018	loops - those are of course safe to use in different threads).	3160	loops - those are of course safe to use in different threads).
3019		3161
3020	Sometimes, however, you need to wake up an event loop you do not control,	3162	Sometimes, however, you need to wake up an event loop you do not control,
3021	for example because it belongs to another thread. This is what C<ev_async>	3163	for example because it belongs to another thread. This is what C<ev_async>
…		…
3389	Associates a different C<struct ev_loop> with this watcher. You can only	3531	Associates a different C<struct ev_loop> with this watcher. You can only
3390	do this when the watcher is inactive (and not pending either).	3532	do this when the watcher is inactive (and not pending either).
3391		3533
3392	=item w->set ([arguments])	3534	=item w->set ([arguments])
3393		3535
3394	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3536	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3395	called at least once. Unlike the C counterpart, an active watcher gets	3537	method or a suitable start method must be called at least once. Unlike the
3396	automatically stopped and restarted when reconfiguring it with this	3538	C counterpart, an active watcher gets automatically stopped and restarted
3397	method.	3539	when reconfiguring it with this method.
3398		3540
3399	=item w->start ()	3541	=item w->start ()
3400		3542
3401	Starts the watcher. Note that there is no C<loop> argument, as the	3543	Starts the watcher. Note that there is no C<loop> argument, as the
3402	constructor already stores the event loop.	3544	constructor already stores the event loop.
3403		3545
		3546	=item w->start ([arguments])
		3547
		3548	Instead of calling C<set> and C<start> methods separately, it is often
		3549	convenient to wrap them in one call. Uses the same type of arguments as
		3550	the configure C<set> method of the watcher.
		3551
3404	=item w->stop ()	3552	=item w->stop ()
3405		3553
3406	Stops the watcher if it is active. Again, no C<loop> argument.	3554	Stops the watcher if it is active. Again, no C<loop> argument.
3407		3555
3408	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3556	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3420		3568
3421	=back	3569	=back
3422		3570
3423	=back	3571	=back
3424		3572
3425	Example: Define a class with an IO and idle watcher, start one of them in	3573	Example: Define a class with two I/O and idle watchers, start the I/O
3426	the constructor.	3574	watchers in the constructor.
3427		3575
3428	class myclass	3576	class myclass
3429	{	3577	{
3430	ev::io io ; void io_cb (ev::io &w, int revents);	3578	ev::io io ; void io_cb (ev::io &w, int revents);
		3579	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3431	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3580	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3432		3581
3433	myclass (int fd)	3582	myclass (int fd)
3434	{	3583	{
3435	io .set <myclass, &myclass::io_cb > (this);	3584	io .set <myclass, &myclass::io_cb > (this);
		3585	io2 .set <myclass, &myclass::io2_cb > (this);
3436	idle.set <myclass, &myclass::idle_cb> (this);	3586	idle.set <myclass, &myclass::idle_cb> (this);
3437		3587
3438	io.start (fd, ev::READ);	3588	io.set (fd, ev::WRITE); // configure the watcher
		3589	io.start (); // start it whenever convenient
		3590
		3591	io2.start (fd, ev::READ); // set + start in one call
3439	}	3592	}
3440	};	3593	};
3441		3594
3442		3595
3443	=head1 OTHER LANGUAGE BINDINGS	3596	=head1 OTHER LANGUAGE BINDINGS
…		…
3517	loop argument"). The C<EV_A> form is used when this is the sole argument,	3670	loop argument"). The C<EV_A> form is used when this is the sole argument,
3518	C<EV_A_> is used when other arguments are following. Example:	3671	C<EV_A_> is used when other arguments are following. Example:
3519		3672
3520	ev_unref (EV_A);	3673	ev_unref (EV_A);
3521	ev_timer_add (EV_A_ watcher);	3674	ev_timer_add (EV_A_ watcher);
3522	ev_loop (EV_A_ 0);	3675	ev_run (EV_A_ 0);
3523		3676
3524	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3677	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3525	which is often provided by the following macro.	3678	which is often provided by the following macro.
3526		3679
3527	=item C<EV_P>, C<EV_P_>	3680	=item C<EV_P>, C<EV_P_>
…		…
3567	}	3720	}
3568		3721
3569	ev_check check;	3722	ev_check check;
3570	ev_check_init (&check, check_cb);	3723	ev_check_init (&check, check_cb);
3571	ev_check_start (EV_DEFAULT_ &check);	3724	ev_check_start (EV_DEFAULT_ &check);
3572	ev_loop (EV_DEFAULT_ 0);	3725	ev_run (EV_DEFAULT_ 0);
3573		3726
3574	=head1 EMBEDDING	3727	=head1 EMBEDDING
3575		3728
3576	Libev can (and often is) directly embedded into host	3729	Libev can (and often is) directly embedded into host
3577	applications. Examples of applications that embed it include the Deliantra	3730	applications. Examples of applications that embed it include the Deliantra
…		…
3668	to a compiled library. All other symbols change the ABI, which means all	3821	to a compiled library. All other symbols change the ABI, which means all
3669	users of libev and the libev code itself must be compiled with compatible	3822	users of libev and the libev code itself must be compiled with compatible
3670	settings.	3823	settings.
3671		3824
3672	=over 4	3825	=over 4
		3826
		3827	=item EV_COMPAT3 (h)
		3828
		3829	Backwards compatibility is a major concern for libev. This is why this
		3830	release of libev comes with wrappers for the functions and symbols that
		3831	have been renamed between libev version 3 and 4.
		3832
		3833	You can disable these wrappers (to test compatibility with future
		3834	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3835	sources. This has the additional advantage that you can drop the C<struct>
		3836	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3837	typedef in that case.
		3838
		3839	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3840	and in some even more future version the compatibility code will be
		3841	removed completely.
3673		3842
3674	=item EV_STANDALONE (h)	3843	=item EV_STANDALONE (h)
3675		3844
3676	Must always be C<1> if you do not use autoconf configuration, which	3845	Must always be C<1> if you do not use autoconf configuration, which
3677	keeps libev from including F<config.h>, and it also defines dummy	3846	keeps libev from including F<config.h>, and it also defines dummy
…		…
4027	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4196	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4028	will be C<0>.	4197	will be C<0>.
4029		4198
4030	=item EV_VERIFY	4199	=item EV_VERIFY
4031		4200
4032	Controls how much internal verification (see C<ev_loop_verify ()>) will	4201	Controls how much internal verification (see C<ev_verify ()>) will
4033	be done: If set to C<0>, no internal verification code will be compiled	4202	be done: If set to C<0>, no internal verification code will be compiled
4034	in. If set to C<1>, then verification code will be compiled in, but not	4203	in. If set to C<1>, then verification code will be compiled in, but not
4035	called. If set to C<2>, then the internal verification code will be	4204	called. If set to C<2>, then the internal verification code will be
4036	called once per loop, which can slow down libev. If set to C<3>, then the	4205	called once per loop, which can slow down libev. If set to C<3>, then the
4037	verification code will be called very frequently, which will slow down	4206	verification code will be called very frequently, which will slow down
…		…
4252	userdata *u = ev_userdata (EV_A);	4421	userdata *u = ev_userdata (EV_A);
4253	pthread_mutex_lock (&u->lock);	4422	pthread_mutex_lock (&u->lock);
4254	}	4423	}
4255		4424
4256	The event loop thread first acquires the mutex, and then jumps straight	4425	The event loop thread first acquires the mutex, and then jumps straight
4257	into C<ev_loop>:	4426	into C<ev_run>:
4258		4427
4259	void *	4428	void *
4260	l_run (void *thr_arg)	4429	l_run (void *thr_arg)
4261	{	4430	{
4262	struct ev_loop loop = (struct ev_loop )thr_arg;	4431	struct ev_loop loop = (struct ev_loop )thr_arg;
4263		4432
4264	l_acquire (EV_A);	4433	l_acquire (EV_A);
4265	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4434	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4266	ev_loop (EV_A_ 0);	4435	ev_run (EV_A_ 0);
4267	l_release (EV_A);	4436	l_release (EV_A);
4268		4437
4269	return 0;	4438	return 0;
4270	}	4439	}
4271		4440
…		…
4323		4492
4324	=head3 COROUTINES	4493	=head3 COROUTINES
4325		4494
4326	Libev is very accommodating to coroutines ("cooperative threads"):	4495	Libev is very accommodating to coroutines ("cooperative threads"):
4327	libev fully supports nesting calls to its functions from different	4496	libev fully supports nesting calls to its functions from different
4328	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4497	coroutines (e.g. you can call C<ev_run> on the same loop from two
4329	different coroutines, and switch freely between both coroutines running	4498	different coroutines, and switch freely between both coroutines running
4330	the loop, as long as you don't confuse yourself). The only exception is	4499	the loop, as long as you don't confuse yourself). The only exception is
4331	that you must not do this from C<ev_periodic> reschedule callbacks.	4500	that you must not do this from C<ev_periodic> reschedule callbacks.
4332		4501
4333	Care has been taken to ensure that libev does not keep local state inside	4502	Care has been taken to ensure that libev does not keep local state inside
4334	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4503	C<ev_run>, and other calls do not usually allow for coroutine switches as
4335	they do not call any callbacks.	4504	they do not call any callbacks.
4336		4505
4337	=head2 COMPILER WARNINGS	4506	=head2 COMPILER WARNINGS
4338		4507
4339	Depending on your compiler and compiler settings, you might get no or a	4508	Depending on your compiler and compiler settings, you might get no or a
…		…
4423	=head3 C<kqueue> is buggy	4592	=head3 C<kqueue> is buggy
4424		4593
4425	The kqueue syscall is broken in all known versions - most versions support	4594	The kqueue syscall is broken in all known versions - most versions support
4426	only sockets, many support pipes.	4595	only sockets, many support pipes.
4427		4596
		4597	Libev tries to work around this by not using C<kqueue> by default on this
		4598	rotten platform, but of course you can still ask for it when creating a
		4599	loop - embedding a socket-only kqueue loop into a select-based one is
		4600	probably going to work well.
		4601
4428	=head3 C<poll> is buggy	4602	=head3 C<poll> is buggy
4429		4603
4430	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>	4604	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
4431	implementation by something calling C<kqueue> internally around the 10.5.6	4605	implementation by something calling C<kqueue> internally around the 10.5.6
4432	release, so now C<kqueue> I<and> C<poll> are broken.	4606	release, so now C<kqueue> I<and> C<poll> are broken.
4433		4607
4434	Libev tries to work around this by neither using C<kqueue> nor C<poll> by	4608	Libev tries to work around this by not using C<poll> by default on
4435	default on this rotten platform, but of course you cna still ask for them	4609	this rotten platform, but of course you can still ask for it when creating
4436	when creating a loop.	4610	a loop.
4437		4611
4438	=head3 C<select> is buggy	4612	=head3 C<select> is buggy
4439		4613
4440	All that's left is C<select>, and of course Apple found a way to fuck this	4614	All that's left is C<select>, and of course Apple found a way to fuck this
4441	one up as well: On OS/X, C<select> actively limits the number of file	4615	one up as well: On OS/X, C<select> actively limits the number of file
4442	descriptors you can pass in to 1024 - your program suddenyl crashes when	4616	descriptors you can pass in to 1024 - your program suddenly crashes when
4443	you use more.	4617	you use more.
4444		4618
4445	There is an undocumented "workaround" for this - defining	4619	There is an undocumented "workaround" for this - defining
4446	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>	4620	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
4447	work on OS/X.	4621	work on OS/X.
…		…
4450		4624
4451	=head3 C<errno> reentrancy	4625	=head3 C<errno> reentrancy
4452		4626
4453	The default compile environment on Solaris is unfortunately so	4627	The default compile environment on Solaris is unfortunately so
4454	thread-unsafe that you can't even use components/libraries compiled	4628	thread-unsafe that you can't even use components/libraries compiled
4455	without C<-D_REENTRANT> (as long as they use C<errno>), which, of course,	4629	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
4456	isn't defined by default.	4630	defined by default. A valid, if stupid, implementation choice.
4457		4631
4458	If you want to use libev in threaded environments you have to make sure	4632	If you want to use libev in threaded environments you have to make sure
4459	it's compiled with C<_REENTRANT> defined.	4633	it's compiled with C<_REENTRANT> defined.
4460		4634
4461	=head3 Event port backend	4635	=head3 Event port backend
4462		4636
4463	The scalable event interface for Solaris is called "event ports". Unfortunately,	4637	The scalable event interface for Solaris is called "event
4464	this mechanism is very buggy. If you run into high CPU usage, your program	4638	ports". Unfortunately, this mechanism is very buggy in all major
		4639	releases. If you run into high CPU usage, your program freezes or you get
4465	freezes or you get a large number of spurious wakeups, make sure you have	4640	a large number of spurious wakeups, make sure you have all the relevant
4466	all the relevant and latest kernel patches applied. No, I don't know which	4641	and latest kernel patches applied. No, I don't know which ones, but there
4467	ones, but there are multiple ones.	4642	are multiple ones to apply, and afterwards, event ports actually work
		4643	great.
4468		4644
4469	If you can't get it to work, you can try running the program with	4645	If you can't get it to work, you can try running the program by setting
4470	C<LIBEV_FLAGS=3> to only allow C<poll> and C<select> backends.	4646	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4647	C<select> backends.
4471		4648
4472	=head2 AIX POLL BUG	4649	=head2 AIX POLL BUG
4473		4650
4474	AIX unfortunately has a broken C<poll.h> header. Libev works around	4651	AIX unfortunately has a broken C<poll.h> header. Libev works around
4475	this by trying to avoid the poll backend altogether (i.e. it's not even	4652	this by trying to avoid the poll backend altogether (i.e. it's not even
4476	compiled in), which normally isn't a big problem as C<select> works fine	4653	compiled in), which normally isn't a big problem as C<select> works fine
4477	with large bitsets, and AIX is dead anyway.	4654	with large bitsets on AIX, and AIX is dead anyway.
4478		4655
4479	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4656	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
4480		4657
4481	=head3 General issues	4658	=head3 General issues
4482		4659
…		…
4588	structure (guaranteed by POSIX but not by ISO C for example), but it also	4765	structure (guaranteed by POSIX but not by ISO C for example), but it also
4589	assumes that the same (machine) code can be used to call any watcher	4766	assumes that the same (machine) code can be used to call any watcher
4590	callback: The watcher callbacks have different type signatures, but libev	4767	callback: The watcher callbacks have different type signatures, but libev
4591	calls them using an C<ev_watcher *> internally.	4768	calls them using an C<ev_watcher *> internally.
4592		4769
		4770	=item pointer accesses must be thread-atomic
		4771
		4772	Accessing a pointer value must be atomic, it must both be readable and
		4773	writable in one piece - this is the case on all current architectures.
		4774
4593	=item C<sig_atomic_t volatile> must be thread-atomic as well	4775	=item C<sig_atomic_t volatile> must be thread-atomic as well
4594		4776
4595	The type C<sig_atomic_t volatile> (or whatever is defined as	4777	The type C<sig_atomic_t volatile> (or whatever is defined as
4596	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different	4778	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
4597	threads. This is not part of the specification for C<sig_atomic_t>, but is	4779	threads. This is not part of the specification for C<sig_atomic_t>, but is
…		…
4619	watchers.	4801	watchers.
4620		4802
4621	=item C<double> must hold a time value in seconds with enough accuracy	4803	=item C<double> must hold a time value in seconds with enough accuracy
4622		4804
4623	The type C<double> is used to represent timestamps. It is required to	4805	The type C<double> is used to represent timestamps. It is required to
4624	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4806	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4625	enough for at least into the year 4000. This requirement is fulfilled by	4807	good enough for at least into the year 4000 with millisecond accuracy
		4808	(the design goal for libev). This requirement is overfulfilled by
4626	implementations implementing IEEE 754, which is basically all existing	4809	implementations using IEEE 754, which is basically all existing ones. With
4627	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4810	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4628	2200.
4629		4811
4630	=back	4812	=back
4631		4813
4632	If you know of other additional requirements drop me a note.	4814	If you know of other additional requirements drop me a note.
4633		4815
…		…
4703	=back	4885	=back
4704		4886
4705		4887
4706	=head1 PORTING FROM LIBEV 3.X TO 4.X	4888	=head1 PORTING FROM LIBEV 3.X TO 4.X
4707		4889
4708	The major version 4 introduced some minor incompatible changes to the API.	4890	The major version 4 introduced some incompatible changes to the API.
4709		4891
4710	At the moment, the C<ev.h> header file tries to implement superficial	4892	At the moment, the C<ev.h> header file provides compatibility definitions
4711	compatibility, so most programs should still compile. Those might be	4893	for all changes, so most programs should still compile. The compatibility
4712	removed in later versions of libev, so better update early than late.	4894	layer might be removed in later versions of libev, so better update to the
		4895	new API early than late.
4713		4896
4714	=over 4	4897	=over 4
4715		4898
4716	=item C<ev_loop_count> renamed to C<ev_iteration>	4899	=item C<EV_COMPAT3> backwards compatibility mechanism
4717		4900
4718	=item C<ev_loop_depth> renamed to C<ev_depth>	4901	The backward compatibility mechanism can be controlled by
		4902	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4903	section.
4719		4904
4720	=item C<ev_loop_verify> renamed to C<ev_verify>	4905	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4906
		4907	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4908
		4909	ev_loop_destroy (EV_DEFAULT_UC);
		4910	ev_loop_fork (EV_DEFAULT);
		4911
		4912	=item function/symbol renames
		4913
		4914	A number of functions and symbols have been renamed:
		4915
		4916	ev_loop => ev_run
		4917	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4918	EVLOOP_ONESHOT => EVRUN_ONCE
		4919
		4920	ev_unloop => ev_break
		4921	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4922	EVUNLOOP_ONE => EVBREAK_ONE
		4923	EVUNLOOP_ALL => EVBREAK_ALL
		4924
		4925	EV_TIMEOUT => EV_TIMER
		4926
		4927	ev_loop_count => ev_iteration
		4928	ev_loop_depth => ev_depth
		4929	ev_loop_verify => ev_verify
4721		4930
4722	Most functions working on C<struct ev_loop> objects don't have an	4931	Most functions working on C<struct ev_loop> objects don't have an
4723	C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is	4932	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4933	associated constants have been renamed to not collide with the C<struct
		4934	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4935	as all other watcher types. Note that C<ev_loop_fork> is still called
4724	still called C<ev_loop_fork> because it would otherwise clash with the	4936	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4725	C<ev_fork> typedef.	4937	typedef.
4726
4727	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>
4728
4729	This is a simple rename - all other watcher types use their name
4730	as revents flag, and now C<ev_timer> does, too.
4731
4732	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4733	and continue to be present for the foreseeable future, so this is mostly a
4734	documentation change.
4735		4938
4736	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4939	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4737		4940
4738	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4941	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4739	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4942	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
…		…
4746		4949
4747	=over 4	4950	=over 4
4748		4951
4749	=item active	4952	=item active
4750		4953
4751	A watcher is active as long as it has been started (has been attached to	4954	A watcher is active as long as it has been started and not yet stopped.
4752	an event loop) but not yet stopped (disassociated from the event loop).	4955	See L<WATCHER STATES> for details.
4753		4956
4754	=item application	4957	=item application
4755		4958
4756	In this document, an application is whatever is using libev.	4959	In this document, an application is whatever is using libev.
		4960
		4961	=item backend
		4962
		4963	The part of the code dealing with the operating system interfaces.
4757		4964
4758	=item callback	4965	=item callback
4759		4966
4760	The address of a function that is called when some event has been	4967	The address of a function that is called when some event has been
4761	detected. Callbacks are being passed the event loop, the watcher that	4968	detected. Callbacks are being passed the event loop, the watcher that
4762	received the event, and the actual event bitset.	4969	received the event, and the actual event bitset.
4763		4970
4764	=item callback invocation	4971	=item callback/watcher invocation
4765		4972
4766	The act of calling the callback associated with a watcher.	4973	The act of calling the callback associated with a watcher.
4767		4974
4768	=item event	4975	=item event
4769		4976
…		…
4788	The model used to describe how an event loop handles and processes	4995	The model used to describe how an event loop handles and processes
4789	watchers and events.	4996	watchers and events.
4790		4997
4791	=item pending	4998	=item pending
4792		4999
4793	A watcher is pending as soon as the corresponding event has been detected,	5000	A watcher is pending as soon as the corresponding event has been
4794	and stops being pending as soon as the watcher will be invoked or its	5001	detected. See L<WATCHER STATES> for details.
4795	pending status is explicitly cleared by the application.
4796
4797	A watcher can be pending, but not active. Stopping a watcher also clears
4798	its pending status.
4799		5002
4800	=item real time	5003	=item real time
4801		5004
4802	The physical time that is observed. It is apparently strictly monotonic :)	5005	The physical time that is observed. It is apparently strictly monotonic :)
4803		5006
…		…
4810	=item watcher	5013	=item watcher
4811		5014
4812	A data structure that describes interest in certain events. Watchers need	5015	A data structure that describes interest in certain events. Watchers need
4813	to be started (attached to an event loop) before they can receive events.	5016	to be started (attached to an event loop) before they can receive events.
4814		5017
4815	=item watcher invocation
4816
4817	The act of calling the callback associated with a watcher.
4818
4819	=back	5018	=back
4820		5019
4821	=head1 AUTHOR	5020	=head1 AUTHOR
4822		5021
4823	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5022	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
		5023	Magnusson and Emanuele Giaquinta.
4824		5024

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Comparing libev/ev.pod (file contents): Revision 1.303 by root, Thu Oct 14 04:29:34 2010 UTC vs. Revision 1.337 by root, Sun Oct 31 20:20:20 2010 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.303 by root, Thu Oct 14 04:29:34 2010 UTC vs.
Revision 1.337 by root, Sun Oct 31 20:20:20 2010 UTC