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Revision 1.290 by root, Tue Mar 16 18:03:01 2010 UTC vs.
Revision 1.329 by root, Sun Oct 24 20:16:00 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
…		…
75	While this document tries to be as complete as possible in documenting	75	While this document tries to be as complete as possible in documenting
76	libev, its usage and the rationale behind its design, it is not a tutorial	76	libev, its usage and the rationale behind its design, it is not a tutorial
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	Familarity 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		82
83	=head1 ABOUT LIBEV	83	=head1 ABOUT LIBEV
84		84
85	Libev is an event loop: you register interest in certain events (such as a	85	Libev is an event loop: you register interest in certain events (such as a
…		…
124	this argument.	124	this argument.
125		125
126	=head2 TIME REPRESENTATION	126	=head2 TIME REPRESENTATION
127		127
128	Libev represents time as a single floating point number, representing	128	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (somewhere	129	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	near the beginning of 1970, details are complicated, don't ask). This	130	somewhere near the beginning of 1970, details are complicated, don't
131	type is called C<ev_tstamp>, which is what you should use too. It usually	131	ask). This type is called C<ev_tstamp>, which is what you should use
132	aliases to the C<double> type in C. When you need to do any calculations	132	too. It usually aliases to the C<double> type in C. When you need to do
133	on it, you should treat it as some floating point value. Unlike the name	133	any calculations on it, you should treat it as some floating point value.
		134
134	component C<stamp> might indicate, it is also used for time differences	135	Unlike the name component C<stamp> might indicate, it is also used for
135	throughout libev.	136	time differences (e.g. delays) throughout libev.
136		137
137	=head1 ERROR HANDLING	138	=head1 ERROR HANDLING
138		139
139	Libev knows three classes of errors: operating system errors, usage errors	140	Libev knows three classes of errors: operating system errors, usage errors
140	and internal errors (bugs).	141	and internal errors (bugs).
…		…
164		165
165	=item ev_tstamp ev_time ()	166	=item ev_tstamp ev_time ()
166		167
167	Returns the current time as libev would use it. Please note that the	168	Returns the current time as libev would use it. Please note that the
168	C<ev_now> function is usually faster and also often returns the timestamp	169	C<ev_now> function is usually faster and also often returns the timestamp
169	you actually want to know.	170	you actually want to know. Also interesting is the combination of
		171	C<ev_update_now> and C<ev_now>.
170		172
171	=item ev_sleep (ev_tstamp interval)	173	=item ev_sleep (ev_tstamp interval)
172		174
173	Sleep for the given interval: The current thread will be blocked until	175	Sleep for the given interval: The current thread will be blocked until
174	either it is interrupted or the given time interval has passed. Basically	176	either it is interrupted or the given time interval has passed. Basically
…		…
191	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
192	compatible to older versions, so a larger minor version alone is usually	194	compatible to older versions, so a larger minor version alone is usually
193	not a problem.	195	not a problem.
194		196
195	Example: Make sure we haven't accidentally been linked against the wrong	197	Example: Make sure we haven't accidentally been linked against the wrong
196	version.	198	version (note, however, that this will not detect other ABI mismatches,
		199	such as LFS or reentrancy).
197		200
198	assert (("libev version mismatch",	201	assert (("libev version mismatch",
199	ev_version_major () == EV_VERSION_MAJOR	202	ev_version_major () == EV_VERSION_MAJOR
200	&& ev_version_minor () >= EV_VERSION_MINOR));	203	&& ev_version_minor () >= EV_VERSION_MINOR));
201		204
…		…
212	assert (("sorry, no epoll, no sex",	215	assert (("sorry, no epoll, no sex",
213	ev_supported_backends () & EVBACKEND_EPOLL));	216	ev_supported_backends () & EVBACKEND_EPOLL));
214		217
215	=item unsigned int ev_recommended_backends ()	218	=item unsigned int ev_recommended_backends ()
216		219
217	Return the set of all backends compiled into this binary of libev and also	220	Return the set of all backends compiled into this binary of libev and
218	recommended for this platform. This set is often smaller than the one	221	also recommended for this platform, meaning it will work for most file
		222	descriptor types. This set is often smaller than the one returned by
219	returned by C<ev_supported_backends>, as for example kqueue is broken on	223	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
220	most BSDs and will not be auto-detected unless you explicitly request it	224	and will not be auto-detected unless you explicitly request it (assuming
221	(assuming you know what you are doing). This is the set of backends that	225	you know what you are doing). This is the set of backends that libev will
222	libev will probe for if you specify no backends explicitly.	226	probe for if you specify no backends explicitly.
223		227
224	=item unsigned int ev_embeddable_backends ()	228	=item unsigned int ev_embeddable_backends ()
225		229
226	Returns the set of backends that are embeddable in other event loops. This	230	Returns the set of backends that are embeddable in other event loops. This
227	is the theoretical, all-platform, value. To find which backends	231	value is platform-specific but can include backends not available on the
228	might be supported on the current system, you would need to look at	232	current system. To find which embeddable backends might be supported on
229	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	233	the current system, you would need to look at C<ev_embeddable_backends ()
230	recommended ones.	234	& ev_supported_backends ()>, likewise for recommended ones.
231		235
232	See the description of C<ev_embed> watchers for more info.	236	See the description of C<ev_embed> watchers for more info.
233		237
234	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]	238	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]
235		239
…		…
289	...	293	...
290	ev_set_syserr_cb (fatal_error);	294	ev_set_syserr_cb (fatal_error);
291		295
292	=back	296	=back
293		297
294	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	298	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
295		299
296	An event loop is described by a C<struct ev_loop *> (the C<struct>	300	An event loop is described by a C<struct ev_loop *> (the C<struct> is
297	is I<not> optional in this case, as there is also an C<ev_loop>	301	I<not> optional in this case unless libev 3 compatibility is disabled, as
298	I<function>).	302	libev 3 had an C<ev_loop> function colliding with the struct name).
299		303
300	The library knows two types of such loops, the I<default> loop, which	304	The library knows two types of such loops, the I<default> loop, which
301	supports signals and child events, and dynamically created loops which do	305	supports signals and child events, and dynamically created event loops
302	not.	306	which do not.
303		307
304	=over 4	308	=over 4
305		309
306	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
307		311
308	This will initialise the default event loop if it hasn't been initialised	312	This returns the "default" event loop object, which is what you should
309	yet and return it. If the default loop could not be initialised, returns	313	normally use when you just need "the event loop". Event loop objects and
310	false. If it already was initialised it simply returns it (and ignores the	314	the C<flags> parameter are described in more detail in the entry for
311	flags. If that is troubling you, check C<ev_backend ()> afterwards).	315	C<ev_loop_new>.
		316
		317	If the default loop is already initialised then this function simply
		318	returns it (and ignores the flags. If that is troubling you, check
		319	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		320	flags, which should almost always be C<0>, unless the caller is also the
		321	one calling C<ev_run> or otherwise qualifies as "the main program".
312		322
313	If you don't know what event loop to use, use the one returned from this	323	If you don't know what event loop to use, use the one returned from this
314	function.	324	function (or via the C<EV_DEFAULT> macro).
315		325
316	Note that this function is I<not> thread-safe, so if you want to use it	326	Note that this function is I<not> thread-safe, so if you want to use it
317	from multiple threads, you have to lock (note also that this is unlikely,	327	from multiple threads, you have to employ some kind of mutex (note also
318	as loops cannot be shared easily between threads anyway).	328	that this case is unlikely, as loops cannot be shared easily between
		329	threads anyway).
319		330
320	The default loop is the only loop that can handle C<ev_signal> and	331	The default loop is the only loop that can handle C<ev_child> watchers,
321	C<ev_child> watchers, and to do this, it always registers a handler	332	and to do this, it always registers a handler for C<SIGCHLD>. If this is
322	for C<SIGCHLD>. If this is a problem for your application you can either	333	a problem for your application you can either create a dynamic loop with
323	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	334	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
324	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	335	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
325	C<ev_default_init>.	336
		337	Example: This is the most typical usage.
		338
		339	if (!ev_default_loop (0))
		340	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		341
		342	Example: Restrict libev to the select and poll backends, and do not allow
		343	environment settings to be taken into account:
		344
		345	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
		346
		347	=item struct ev_loop *ev_loop_new (unsigned int flags)
		348
		349	This will create and initialise a new event loop object. If the loop
		350	could not be initialised, returns false.
		351
		352	Note that this function I<is> thread-safe, and one common way to use
		353	libev with threads is indeed to create one loop per thread, and using the
		354	default loop in the "main" or "initial" thread.
326		355
327	The flags argument can be used to specify special behaviour or specific	356	The flags argument can be used to specify special behaviour or specific
328	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	357	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
329		358
330	The following flags are supported:	359	The following flags are supported:
…		…
345	useful to try out specific backends to test their performance, or to work	374	useful to try out specific backends to test their performance, or to work
346	around bugs.	375	around bugs.
347		376
348	=item C<EVFLAG_FORKCHECK>	377	=item C<EVFLAG_FORKCHECK>
349		378
350	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	379	Instead of calling C<ev_loop_fork> manually after a fork, you can also
351	a fork, you can also make libev check for a fork in each iteration by	380	make libev check for a fork in each iteration by enabling this flag.
352	enabling this flag.
353		381
354	This works by calling C<getpid ()> on every iteration of the loop,	382	This works by calling C<getpid ()> on every iteration of the loop,
355	and thus this might slow down your event loop if you do a lot of loop	383	and thus this might slow down your event loop if you do a lot of loop
356	iterations and little real work, but is usually not noticeable (on my	384	iterations and little real work, but is usually not noticeable (on my
357	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	385	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
…		…
439	of course I<doesn't>, and epoll just loves to report events for totally	467	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	468	I<different> file descriptors (even already closed ones, so one cannot
441	even remove them from the set) than registered in the set (especially	469	even remove them from the set) than registered in the set (especially
442	on SMP systems). Libev tries to counter these spurious notifications by	470	on SMP systems). Libev tries to counter these spurious notifications by
443	employing an additional generation counter and comparing that against the	471	employing an additional generation counter and comparing that against the
444	events to filter out spurious ones, recreating the set when required.	472	events to filter out spurious ones, recreating the set when required. Last
		473	not least, it also refuses to work with some file descriptors which work
		474	perfectly fine with C<select> (files, many character devices...).
445		475
446	While stopping, setting and starting an I/O watcher in the same iteration	476	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	477	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	478	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	479	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,	577	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	578	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	579	here). If none are specified, all backends in C<ev_recommended_backends
550	()> will be tried.	580	()> will be tried.
551		581
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.	582	Example: Try to create a event loop that uses epoll and nothing else.
579		583
580	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
581	if (!epoller)	585	if (!epoller)
582	fatal ("no epoll found here, maybe it hides under your chair");	586	fatal ("no epoll found here, maybe it hides under your chair");
583		587
		588	Example: Use whatever libev has to offer, but make sure that kqueue is
		589	used if available.
		590
		591	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
		592
584	=item ev_default_destroy ()	593	=item ev_loop_destroy (loop)
585		594
586	Destroys the default loop (frees all memory and kernel state etc.). None	595	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	596	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	597	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,	598	responsibility to either stop all watchers cleanly yourself I<before>
590	or cope with the fact afterwards (which is usually the easiest thing, you	599	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).	600	the easiest thing, you can just ignore the watchers and/or C<free ()> them
		601	for example).
592		602
593	Note that certain global state, such as signal state (and installed signal	603	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	604	handlers), will not be freed by this function, and related watchers (such
595	as signal and child watchers) would need to be stopped manually.	605	as signal and child watchers) would need to be stopped manually.
596		606
597	In general it is not advisable to call this function except in the	607	This function is normally used on loop objects allocated by
598	rare occasion where you really need to free e.g. the signal handling	608	C<ev_loop_new>, but it can also be used on the default loop returned by
		609	C<ev_default_loop>, in which case it is not thread-safe.
		610
		611	Note that it is not advisable to call this function on the default loop
		612	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	613	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>.	614	and C<ev_loop_destroy>.
601		615
602	=item ev_loop_destroy (loop)	616	=item ev_loop_fork (loop)
603		617
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	618	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	619	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	620	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	621	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	622	child before resuming or calling C<ev_run>.
614	functions, and it will only take effect at the next C<ev_loop> iteration.	623
		624	Again, you I<have> to call it on I<any> loop that you want to re-use after
		625	a fork, I<even if you do not plan to use the loop in the parent>. This is
		626	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
		627	during fork.
615		628
616	On the other hand, you only need to call this function in the child	629	On the other hand, you only need to call this function in the child
617	process if and only if you want to use the event library in the child. If	630	process if and only if you want to use the event loop in the child. If
618	you just fork+exec, you don't have to call it at all.	631	you just fork+exec or create a new loop in the child, you don't have to
		632	call it at all (in fact, C<epoll> is so badly broken that it makes a
		633	difference, but libev will usually detect this case on its own and do a
		634	costly reset of the backend).
619		635
620	The function itself is quite fast and it's usually not a problem to call	636	The function itself is quite fast and it's usually not a problem to call
621	it just in case after a fork. To make this easy, the function will fit in	637	it just in case after a fork.
622	quite nicely into a call to C<pthread_atfork>:
623		638
		639	Example: Automate calling C<ev_loop_fork> on the default loop when
		640	using pthreads.
		641
		642	static void
		643	post_fork_child (void)
		644	{
		645	ev_loop_fork (EV_DEFAULT);
		646	}
		647
		648	...
624	pthread_atfork (0, 0, ev_default_fork);	649	pthread_atfork (0, 0, post_fork_child);
625
626	=item ev_loop_fork (loop)
627
628	Like C<ev_default_fork>, but acts on an event loop created by
629	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
630	after fork that you want to re-use in the child, and how you do this is
631	entirely your own problem.
632		650
633	=item int ev_is_default_loop (loop)	651	=item int ev_is_default_loop (loop)
634		652
635	Returns true when the given loop is, in fact, the default loop, and false	653	Returns true when the given loop is, in fact, the default loop, and false
636	otherwise.	654	otherwise.
637		655
638	=item unsigned int ev_loop_count (loop)	656	=item unsigned int ev_iteration (loop)
639		657
640	Returns the count of loop iterations for the loop, which is identical to	658	Returns the current iteration count for the event loop, which is identical
641	the number of times libev did poll for new events. It starts at C<0> and	659	to the number of times libev did poll for new events. It starts at C<0>
642	happily wraps around with enough iterations.	660	and happily wraps around with enough iterations.
643		661
644	This value can sometimes be useful as a generation counter of sorts (it	662	This value can sometimes be useful as a generation counter of sorts (it
645	"ticks" the number of loop iterations), as it roughly corresponds with	663	"ticks" the number of loop iterations), as it roughly corresponds with
646	C<ev_prepare> and C<ev_check> calls.	664	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		665	prepare and check phases.
647		666
648	=item unsigned int ev_loop_depth (loop)	667	=item unsigned int ev_depth (loop)
649		668
650	Returns the number of times C<ev_loop> was entered minus the number of	669	Returns the number of times C<ev_run> was entered minus the number of
651	times C<ev_loop> was exited, in other words, the recursion depth.	670	times C<ev_run> was exited, in other words, the recursion depth.
652		671
653	Outside C<ev_loop>, this number is zero. In a callback, this number is	672	Outside C<ev_run>, this number is zero. In a callback, this number is
654	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	673	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
655	in which case it is higher.	674	in which case it is higher.
656		675
657	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	676	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
658	etc.), doesn't count as exit.	677	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		678	ungentleman-like behaviour unless it's really convenient.
659		679
660	=item unsigned int ev_backend (loop)	680	=item unsigned int ev_backend (loop)
661		681
662	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	682	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
663	use.	683	use.
…		…
672		692
673	=item ev_now_update (loop)	693	=item ev_now_update (loop)
674		694
675	Establishes the current time by querying the kernel, updating the time	695	Establishes the current time by querying the kernel, updating the time
676	returned by C<ev_now ()> in the progress. This is a costly operation and	696	returned by C<ev_now ()> in the progress. This is a costly operation and
677	is usually done automatically within C<ev_loop ()>.	697	is usually done automatically within C<ev_run ()>.
678		698
679	This function is rarely useful, but when some event callback runs for a	699	This function is rarely useful, but when some event callback runs for a
680	very long time without entering the event loop, updating libev's idea of	700	very long time without entering the event loop, updating libev's idea of
681	the current time is a good idea.	701	the current time is a good idea.
682		702
…		…
684		704
685	=item ev_suspend (loop)	705	=item ev_suspend (loop)
686		706
687	=item ev_resume (loop)	707	=item ev_resume (loop)
688		708
689	These two functions suspend and resume a loop, for use when the loop is	709	These two functions suspend and resume an event loop, for use when the
690	not used for a while and timeouts should not be processed.	710	loop is not used for a while and timeouts should not be processed.
691		711
692	A typical use case would be an interactive program such as a game: When	712	A typical use case would be an interactive program such as a game: When
693	the user presses C<^Z> to suspend the game and resumes it an hour later it	713	the user presses C<^Z> to suspend the game and resumes it an hour later it
694	would be best to handle timeouts as if no time had actually passed while	714	would be best to handle timeouts as if no time had actually passed while
695	the program was suspended. This can be achieved by calling C<ev_suspend>	715	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
697	C<ev_resume> directly afterwards to resume timer processing.	717	C<ev_resume> directly afterwards to resume timer processing.
698		718
699	Effectively, all C<ev_timer> watchers will be delayed by the time spend	719	Effectively, all C<ev_timer> watchers will be delayed by the time spend
700	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	720	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
701	will be rescheduled (that is, they will lose any events that would have	721	will be rescheduled (that is, they will lose any events that would have
702	occured while suspended).	722	occurred while suspended).
703		723
704	After calling C<ev_suspend> you B<must not> call I<any> function on the	724	After calling C<ev_suspend> you B<must not> call I<any> function on the
705	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	725	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
706	without a previous call to C<ev_suspend>.	726	without a previous call to C<ev_suspend>.
707		727
708	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	728	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
709	event loop time (see C<ev_now_update>).	729	event loop time (see C<ev_now_update>).
710		730
711	=item ev_loop (loop, int flags)	731	=item ev_run (loop, int flags)
712		732
713	Finally, this is it, the event handler. This function usually is called	733	Finally, this is it, the event handler. This function usually is called
714	after you have initialised all your watchers and you want to start	734	after you have initialised all your watchers and you want to start
715	handling events.	735	handling events. It will ask the operating system for any new events, call
		736	the watcher callbacks, an then repeat the whole process indefinitely: This
		737	is why event loops are called I<loops>.
716		738
717	If the flags argument is specified as C<0>, it will not return until	739	If the flags argument is specified as C<0>, it will keep handling events
718	either no event watchers are active anymore or C<ev_unloop> was called.	740	until either no event watchers are active anymore or C<ev_break> was
		741	called.
719		742
720	Please note that an explicit C<ev_unloop> is usually better than	743	Please note that an explicit C<ev_break> is usually better than
721	relying on all watchers to be stopped when deciding when a program has	744	relying on all watchers to be stopped when deciding when a program has
722	finished (especially in interactive programs), but having a program	745	finished (especially in interactive programs), but having a program
723	that automatically loops as long as it has to and no longer by virtue	746	that automatically loops as long as it has to and no longer by virtue
724	of relying on its watchers stopping correctly, that is truly a thing of	747	of relying on its watchers stopping correctly, that is truly a thing of
725	beauty.	748	beauty.
726		749
727	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	750	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
728	those events and any already outstanding ones, but will not block your	751	those events and any already outstanding ones, but will not wait and
729	process in case there are no events and will return after one iteration of	752	block your process in case there are no events and will return after one
730	the loop.	753	iteration of the loop. This is sometimes useful to poll and handle new
		754	events while doing lengthy calculations, to keep the program responsive.
731		755
732	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	756	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
733	necessary) and will handle those and any already outstanding ones. It	757	necessary) and will handle those and any already outstanding ones. It
734	will block your process until at least one new event arrives (which could	758	will block your process until at least one new event arrives (which could
735	be an event internal to libev itself, so there is no guarantee that a	759	be an event internal to libev itself, so there is no guarantee that a
736	user-registered callback will be called), and will return after one	760	user-registered callback will be called), and will return after one
737	iteration of the loop.	761	iteration of the loop.
738		762
739	This is useful if you are waiting for some external event in conjunction	763	This is useful if you are waiting for some external event in conjunction
740	with something not expressible using other libev watchers (i.e. "roll your	764	with something not expressible using other libev watchers (i.e. "roll your
741	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	765	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
742	usually a better approach for this kind of thing.	766	usually a better approach for this kind of thing.
743		767
744	Here are the gory details of what C<ev_loop> does:	768	Here are the gory details of what C<ev_run> does:
745		769
		770	- Increment loop depth.
		771	- Reset the ev_break status.
746	- Before the first iteration, call any pending watchers.	772	- Before the first iteration, call any pending watchers.
		773	LOOP:
747	* If EVFLAG_FORKCHECK was used, check for a fork.	774	- If EVFLAG_FORKCHECK was used, check for a fork.
748	- If a fork was detected (by any means), queue and call all fork watchers.	775	- If a fork was detected (by any means), queue and call all fork watchers.
749	- Queue and call all prepare watchers.	776	- Queue and call all prepare watchers.
		777	- If ev_break was called, goto FINISH.
750	- If we have been forked, detach and recreate the kernel state	778	- If we have been forked, detach and recreate the kernel state
751	as to not disturb the other process.	779	as to not disturb the other process.
752	- Update the kernel state with all outstanding changes.	780	- Update the kernel state with all outstanding changes.
753	- Update the "event loop time" (ev_now ()).	781	- Update the "event loop time" (ev_now ()).
754	- Calculate for how long to sleep or block, if at all	782	- Calculate for how long to sleep or block, if at all
755	(active idle watchers, EVLOOP_NONBLOCK or not having	783	(active idle watchers, EVRUN_NOWAIT or not having
756	any active watchers at all will result in not sleeping).	784	any active watchers at all will result in not sleeping).
757	- Sleep if the I/O and timer collect interval say so.	785	- Sleep if the I/O and timer collect interval say so.
		786	- Increment loop iteration counter.
758	- Block the process, waiting for any events.	787	- Block the process, waiting for any events.
759	- Queue all outstanding I/O (fd) events.	788	- Queue all outstanding I/O (fd) events.
760	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	789	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
761	- Queue all expired timers.	790	- Queue all expired timers.
762	- Queue all expired periodics.	791	- Queue all expired periodics.
763	- Unless any events are pending now, queue all idle watchers.	792	- Queue all idle watchers with priority higher than that of pending events.
764	- Queue all check watchers.	793	- Queue all check watchers.
765	- Call all queued watchers in reverse order (i.e. check watchers first).	794	- Call all queued watchers in reverse order (i.e. check watchers first).
766	Signals and child watchers are implemented as I/O watchers, and will	795	Signals and child watchers are implemented as I/O watchers, and will
767	be handled here by queueing them when their watcher gets executed.	796	be handled here by queueing them when their watcher gets executed.
768	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	797	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
769	were used, or there are no active watchers, return, otherwise	798	were used, or there are no active watchers, goto FINISH, otherwise
770	continue with step *.	799	continue with step LOOP.
		800	FINISH:
		801	- Reset the ev_break status iff it was EVBREAK_ONE.
		802	- Decrement the loop depth.
		803	- Return.
771		804
772	Example: Queue some jobs and then loop until no events are outstanding	805	Example: Queue some jobs and then loop until no events are outstanding
773	anymore.	806	anymore.
774		807
775	... queue jobs here, make sure they register event watchers as long	808	... queue jobs here, make sure they register event watchers as long
776	... as they still have work to do (even an idle watcher will do..)	809	... as they still have work to do (even an idle watcher will do..)
777	ev_loop (my_loop, 0);	810	ev_run (my_loop, 0);
778	... jobs done or somebody called unloop. yeah!	811	... jobs done or somebody called unloop. yeah!
779		812
780	=item ev_unloop (loop, how)	813	=item ev_break (loop, how)
781		814
782	Can be used to make a call to C<ev_loop> return early (but only after it	815	Can be used to make a call to C<ev_run> return early (but only after it
783	has processed all outstanding events). The C<how> argument must be either	816	has processed all outstanding events). The C<how> argument must be either
784	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	817	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
785	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	818	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
786		819
787	This "unloop state" will be cleared when entering C<ev_loop> again.	820	This "unloop state" will be cleared when entering C<ev_run> again.
788		821
789	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	822	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
790		823
791	=item ev_ref (loop)	824	=item ev_ref (loop)
792		825
793	=item ev_unref (loop)	826	=item ev_unref (loop)
794		827
795	Ref/unref can be used to add or remove a reference count on the event	828	Ref/unref can be used to add or remove a reference count on the event
796	loop: Every watcher keeps one reference, and as long as the reference	829	loop: Every watcher keeps one reference, and as long as the reference
797	count is nonzero, C<ev_loop> will not return on its own.	830	count is nonzero, C<ev_run> will not return on its own.
798		831
799	This is useful when you have a watcher that you never intend to	832	This is useful when you have a watcher that you never intend to
800	unregister, but that nevertheless should not keep C<ev_loop> from	833	unregister, but that nevertheless should not keep C<ev_run> from
801	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>	834	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
802	before stopping it.	835	before stopping it.
803		836
804	As an example, libev itself uses this for its internal signal pipe: It	837	As an example, libev itself uses this for its internal signal pipe: It
805	is not visible to the libev user and should not keep C<ev_loop> from	838	is not visible to the libev user and should not keep C<ev_run> from
806	exiting if no event watchers registered by it are active. It is also an	839	exiting if no event watchers registered by it are active. It is also an
807	excellent way to do this for generic recurring timers or from within	840	excellent way to do this for generic recurring timers or from within
808	third-party libraries. Just remember to I<unref after start> and I<ref	841	third-party libraries. Just remember to I<unref after start> and I<ref
809	before stop> (but only if the watcher wasn't active before, or was active	842	before stop> (but only if the watcher wasn't active before, or was active
810	before, respectively. Note also that libev might stop watchers itself	843	before, respectively. Note also that libev might stop watchers itself
811	(e.g. non-repeating timers) in which case you have to C<ev_ref>	844	(e.g. non-repeating timers) in which case you have to C<ev_ref>
812	in the callback).	845	in the callback).
813		846
814	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	847	Example: Create a signal watcher, but keep it from keeping C<ev_run>
815	running when nothing else is active.	848	running when nothing else is active.
816		849
817	ev_signal exitsig;	850	ev_signal exitsig;
818	ev_signal_init (&exitsig, sig_cb, SIGINT);	851	ev_signal_init (&exitsig, sig_cb, SIGINT);
819	ev_signal_start (loop, &exitsig);	852	ev_signal_start (loop, &exitsig);
…		…
864	usually doesn't make much sense to set it to a lower value than C<0.01>,	897	usually doesn't make much sense to set it to a lower value than C<0.01>,
865	as this approaches the timing granularity of most systems. Note that if	898	as this approaches the timing granularity of most systems. Note that if
866	you do transactions with the outside world and you can't increase the	899	you do transactions with the outside world and you can't increase the
867	parallelity, then this setting will limit your transaction rate (if you	900	parallelity, then this setting will limit your transaction rate (if you
868	need to poll once per transaction and the I/O collect interval is 0.01,	901	need to poll once per transaction and the I/O collect interval is 0.01,
869	then you can't do more than 100 transations per second).	902	then you can't do more than 100 transactions per second).
870		903
871	Setting the I<timeout collect interval> can improve the opportunity for	904	Setting the I<timeout collect interval> can improve the opportunity for
872	saving power, as the program will "bundle" timer callback invocations that	905	saving power, as the program will "bundle" timer callback invocations that
873	are "near" in time together, by delaying some, thus reducing the number of	906	are "near" in time together, by delaying some, thus reducing the number of
874	times the process sleeps and wakes up again. Another useful technique to	907	times the process sleeps and wakes up again. Another useful technique to
…		…
882	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	915	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
883		916
884	=item ev_invoke_pending (loop)	917	=item ev_invoke_pending (loop)
885		918
886	This call will simply invoke all pending watchers while resetting their	919	This call will simply invoke all pending watchers while resetting their
887	pending state. Normally, C<ev_loop> does this automatically when required,	920	pending state. Normally, C<ev_run> does this automatically when required,
888	but when overriding the invoke callback this call comes handy.	921	but when overriding the invoke callback this call comes handy. This
		922	function can be invoked from a watcher - this can be useful for example
		923	when you want to do some lengthy calculation and want to pass further
		924	event handling to another thread (you still have to make sure only one
		925	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
889		926
890	=item int ev_pending_count (loop)	927	=item int ev_pending_count (loop)
891		928
892	Returns the number of pending watchers - zero indicates that no watchers	929	Returns the number of pending watchers - zero indicates that no watchers
893	are pending.	930	are pending.
894		931
895	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	932	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
896		933
897	This overrides the invoke pending functionality of the loop: Instead of	934	This overrides the invoke pending functionality of the loop: Instead of
898	invoking all pending watchers when there are any, C<ev_loop> will call	935	invoking all pending watchers when there are any, C<ev_run> will call
899	this callback instead. This is useful, for example, when you want to	936	this callback instead. This is useful, for example, when you want to
900	invoke the actual watchers inside another context (another thread etc.).	937	invoke the actual watchers inside another context (another thread etc.).
901		938
902	If you want to reset the callback, use C<ev_invoke_pending> as new	939	If you want to reset the callback, use C<ev_invoke_pending> as new
903	callback.	940	callback.
…		…
906		943
907	Sometimes you want to share the same loop between multiple threads. This	944	Sometimes you want to share the same loop between multiple threads. This
908	can be done relatively simply by putting mutex_lock/unlock calls around	945	can be done relatively simply by putting mutex_lock/unlock calls around
909	each call to a libev function.	946	each call to a libev function.
910		947
911	However, C<ev_loop> can run an indefinite time, so it is not feasible to	948	However, C<ev_run> can run an indefinite time, so it is not feasible
912	wait for it to return. One way around this is to wake up the loop via	949	to wait for it to return. One way around this is to wake up the event
913	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	950	loop via C<ev_break> and C<av_async_send>, another way is to set these
914	and I<acquire> callbacks on the loop.	951	I<release> and I<acquire> callbacks on the loop.
915		952
916	When set, then C<release> will be called just before the thread is	953	When set, then C<release> will be called just before the thread is
917	suspended waiting for new events, and C<acquire> is called just	954	suspended waiting for new events, and C<acquire> is called just
918	afterwards.	955	afterwards.
919		956
…		…
922		959
923	While event loop modifications are allowed between invocations of	960	While event loop modifications are allowed between invocations of
924	C<release> and C<acquire> (that's their only purpose after all), no	961	C<release> and C<acquire> (that's their only purpose after all), no
925	modifications done will affect the event loop, i.e. adding watchers will	962	modifications done will affect the event loop, i.e. adding watchers will
926	have no effect on the set of file descriptors being watched, or the time	963	have no effect on the set of file descriptors being watched, or the time
927	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	964	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
928	to take note of any changes you made.	965	to take note of any changes you made.
929		966
930	In theory, threads executing C<ev_loop> will be async-cancel safe between	967	In theory, threads executing C<ev_run> will be async-cancel safe between
931	invocations of C<release> and C<acquire>.	968	invocations of C<release> and C<acquire>.
932		969
933	See also the locking example in the C<THREADS> section later in this	970	See also the locking example in the C<THREADS> section later in this
934	document.	971	document.
935		972
…		…
944	These two functions can be used to associate arbitrary data with a loop,	981	These two functions can be used to associate arbitrary data with a loop,
945	and are intended solely for the C<invoke_pending_cb>, C<release> and	982	and are intended solely for the C<invoke_pending_cb>, C<release> and
946	C<acquire> callbacks described above, but of course can be (ab-)used for	983	C<acquire> callbacks described above, but of course can be (ab-)used for
947	any other purpose as well.	984	any other purpose as well.
948		985
949	=item ev_loop_verify (loop)	986	=item ev_verify (loop)
950		987
951	This function only does something when C<EV_VERIFY> support has been	988	This function only does something when C<EV_VERIFY> support has been
952	compiled in, which is the default for non-minimal builds. It tries to go	989	compiled in, which is the default for non-minimal builds. It tries to go
953	through all internal structures and checks them for validity. If anything	990	through all internal structures and checks them for validity. If anything
954	is found to be inconsistent, it will print an error message to standard	991	is found to be inconsistent, it will print an error message to standard
…		…
965		1002
966	In the following description, uppercase C<TYPE> in names stands for the	1003	In the following description, uppercase C<TYPE> in names stands for the
967	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1004	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
968	watchers and C<ev_io_start> for I/O watchers.	1005	watchers and C<ev_io_start> for I/O watchers.
969		1006
970	A watcher is a structure that you create and register to record your	1007	A watcher is an opaque structure that you allocate and register to record
971	interest in some event. For instance, if you want to wait for STDIN to	1008	your interest in some event. To make a concrete example, imagine you want
972	become readable, you would create an C<ev_io> watcher for that:	1009	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1010	for that:
973		1011
974	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1012	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
975	{	1013	{
976	ev_io_stop (w);	1014	ev_io_stop (w);
977	ev_unloop (loop, EVUNLOOP_ALL);	1015	ev_break (loop, EVBREAK_ALL);
978	}	1016	}
979		1017
980	struct ev_loop *loop = ev_default_loop (0);	1018	struct ev_loop *loop = ev_default_loop (0);
981		1019
982	ev_io stdin_watcher;	1020	ev_io stdin_watcher;
983		1021
984	ev_init (&stdin_watcher, my_cb);	1022	ev_init (&stdin_watcher, my_cb);
985	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1023	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
986	ev_io_start (loop, &stdin_watcher);	1024	ev_io_start (loop, &stdin_watcher);
987		1025
988	ev_loop (loop, 0);	1026	ev_run (loop, 0);
989		1027
990	As you can see, you are responsible for allocating the memory for your	1028	As you can see, you are responsible for allocating the memory for your
991	watcher structures (and it is I<usually> a bad idea to do this on the	1029	watcher structures (and it is I<usually> a bad idea to do this on the
992	stack).	1030	stack).
993		1031
994	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1032	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
995	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1033	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
996		1034
997	Each watcher structure must be initialised by a call to C<ev_init	1035	Each watcher structure must be initialised by a call to C<ev_init (watcher
998	(watcher *, callback)>, which expects a callback to be provided. This	1036	*, callback)>, which expects a callback to be provided. This callback is
999	callback gets invoked each time the event occurs (or, in the case of I/O	1037	invoked each time the event occurs (or, in the case of I/O watchers, each
1000	watchers, each time the event loop detects that the file descriptor given	1038	time the event loop detects that the file descriptor given is readable
1001	is readable and/or writable).	1039	and/or writable).
1002		1040
1003	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1041	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1004	macro to configure it, with arguments specific to the watcher type. There	1042	macro to configure it, with arguments specific to the watcher type. There
1005	is also a macro to combine initialisation and setting in one call: C<<	1043	is also a macro to combine initialisation and setting in one call: C<<
1006	ev_TYPE_init (watcher *, callback, ...) >>.	1044	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1057		1095
1058	=item C<EV_PREPARE>	1096	=item C<EV_PREPARE>
1059		1097
1060	=item C<EV_CHECK>	1098	=item C<EV_CHECK>
1061		1099
1062	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1100	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1063	to gather new events, and all C<ev_check> watchers are invoked just after	1101	to gather new events, and all C<ev_check> watchers are invoked just after
1064	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1102	C<ev_run> has gathered them, but before it invokes any callbacks for any
1065	received events. Callbacks of both watcher types can start and stop as	1103	received events. Callbacks of both watcher types can start and stop as
1066	many watchers as they want, and all of them will be taken into account	1104	many watchers as they want, and all of them will be taken into account
1067	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1105	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1068	C<ev_loop> from blocking).	1106	C<ev_run> from blocking).
1069		1107
1070	=item C<EV_EMBED>	1108	=item C<EV_EMBED>
1071		1109
1072	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1110	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1073		1111
1074	=item C<EV_FORK>	1112	=item C<EV_FORK>
1075		1113
1076	The event loop has been resumed in the child process after fork (see	1114	The event loop has been resumed in the child process after fork (see
1077	C<ev_fork>).	1115	C<ev_fork>).
		1116
		1117	=item C<EV_CLEANUP>
		1118
		1119	The event loop is abotu to be destroyed (see C<ev_cleanup>).
1078		1120
1079	=item C<EV_ASYNC>	1121	=item C<EV_ASYNC>
1080		1122
1081	The given async watcher has been asynchronously notified (see C<ev_async>).	1123	The given async watcher has been asynchronously notified (see C<ev_async>).
1082		1124
…		…
1101	example it might indicate that a fd is readable or writable, and if your	1143	example it might indicate that a fd is readable or writable, and if your
1102	callbacks is well-written it can just attempt the operation and cope with	1144	callbacks is well-written it can just attempt the operation and cope with
1103	the error from read() or write(). This will not work in multi-threaded	1145	the error from read() or write(). This will not work in multi-threaded
1104	programs, though, as the fd could already be closed and reused for another	1146	programs, though, as the fd could already be closed and reused for another
1105	thing, so beware.	1147	thing, so beware.
		1148
		1149	=back
		1150
		1151	=head2 WATCHER STATES
		1152
		1153	There are various watcher states mentioned throughout this manual -
		1154	active, pending and so on. In this section these states and the rules to
		1155	transition between them will be described in more detail - and while these
		1156	rules might look complicated, they usually do "the right thing".
		1157
		1158	=over 4
		1159
		1160	=item initialiased
		1161
		1162	Before a watcher can be registered with the event looop it has to be
		1163	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1164	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1165
		1166	In this state it is simply some block of memory that is suitable for use
		1167	in an event loop. It can be moved around, freed, reused etc. at will.
		1168
		1169	=item started/running/active
		1170
		1171	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1172	property of the event loop, and is actively waiting for events. While in
		1173	this state it cannot be accessed (except in a few documented ways), moved,
		1174	freed or anything else - the only legal thing is to keep a pointer to it,
		1175	and call libev functions on it that are documented to work on active watchers.
		1176
		1177	=item pending
		1178
		1179	If a watcher is active and libev determines that an event it is interested
		1180	in has occurred (such as a timer expiring), it will become pending. It will
		1181	stay in this pending state until either it is stopped or its callback is
		1182	about to be invoked, so it is not normally pending inside the watcher
		1183	callback.
		1184
		1185	The watcher might or might not be active while it is pending (for example,
		1186	an expired non-repeating timer can be pending but no longer active). If it
		1187	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1188	but it is still property of the event loop at this time, so cannot be
		1189	moved, freed or reused. And if it is active the rules described in the
		1190	previous item still apply.
		1191
		1192	It is also possible to feed an event on a watcher that is not active (e.g.
		1193	via C<ev_feed_event>), in which case it becomes pending without being
		1194	active.
		1195
		1196	=item stopped
		1197
		1198	A watcher can be stopped implicitly by libev (in which case it might still
		1199	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1200	latter will clear any pending state the watcher might be in, regardless
		1201	of whether it was active or not, so stopping a watcher explicitly before
		1202	freeing it is often a good idea.
		1203
		1204	While stopped (and not pending) the watcher is essentially in the
		1205	initialised state, that is it can be reused, moved, modified in any way
		1206	you wish.
1106		1207
1107	=back	1208	=back
1108		1209
1109	=head2 GENERIC WATCHER FUNCTIONS	1210	=head2 GENERIC WATCHER FUNCTIONS
1110		1211
…		…
1372		1473
1373	For example, to emulate how many other event libraries handle priorities,	1474	For example, to emulate how many other event libraries handle priorities,
1374	you can associate an C<ev_idle> watcher to each such watcher, and in	1475	you can associate an C<ev_idle> watcher to each such watcher, and in
1375	the normal watcher callback, you just start the idle watcher. The real	1476	the normal watcher callback, you just start the idle watcher. The real
1376	processing is done in the idle watcher callback. This causes libev to	1477	processing is done in the idle watcher callback. This causes libev to
1377	continously poll and process kernel event data for the watcher, but when	1478	continuously poll and process kernel event data for the watcher, but when
1378	the lock-out case is known to be rare (which in turn is rare :), this is	1479	the lock-out case is known to be rare (which in turn is rare :), this is
1379	workable.	1480	workable.
1380		1481
1381	Usually, however, the lock-out model implemented that way will perform	1482	Usually, however, the lock-out model implemented that way will perform
1382	miserably under the type of load it was designed to handle. In that case,	1483	miserably under the type of load it was designed to handle. In that case,
…		…
1396	{	1497	{
1397	// stop the I/O watcher, we received the event, but	1498	// stop the I/O watcher, we received the event, but
1398	// are not yet ready to handle it.	1499	// are not yet ready to handle it.
1399	ev_io_stop (EV_A_ w);	1500	ev_io_stop (EV_A_ w);
1400		1501
1401	// start the idle watcher to ahndle the actual event.	1502	// start the idle watcher to handle the actual event.
1402	// it will not be executed as long as other watchers	1503	// it will not be executed as long as other watchers
1403	// with the default priority are receiving events.	1504	// with the default priority are receiving events.
1404	ev_idle_start (EV_A_ &idle);	1505	ev_idle_start (EV_A_ &idle);
1405	}	1506	}
1406		1507
…		…
1460		1561
1461	If you cannot use non-blocking mode, then force the use of a	1562	If you cannot use non-blocking mode, then force the use of a
1462	known-to-be-good backend (at the time of this writing, this includes only	1563	known-to-be-good backend (at the time of this writing, this includes only
1463	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1564	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1464	descriptors for which non-blocking operation makes no sense (such as	1565	descriptors for which non-blocking operation makes no sense (such as
1465	files) - libev doesn't guarentee any specific behaviour in that case.	1566	files) - libev doesn't guarantee any specific behaviour in that case.
1466		1567
1467	Another thing you have to watch out for is that it is quite easy to	1568	Another thing you have to watch out for is that it is quite easy to
1468	receive "spurious" readiness notifications, that is your callback might	1569	receive "spurious" readiness notifications, that is your callback might
1469	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1570	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1470	because there is no data. Not only are some backends known to create a	1571	because there is no data. Not only are some backends known to create a
…		…
1538	somewhere, as that would have given you a big clue).	1639	somewhere, as that would have given you a big clue).
1539		1640
1540	=head3 The special problem of accept()ing when you can't	1641	=head3 The special problem of accept()ing when you can't
1541		1642
1542	Many implementations of the POSIX C<accept> function (for example,	1643	Many implementations of the POSIX C<accept> function (for example,
1543	found in port-2004 Linux) have the peculiar behaviour of not removing a	1644	found in post-2004 Linux) have the peculiar behaviour of not removing a
1544	connection from the pending queue in all error cases.	1645	connection from the pending queue in all error cases.
1545		1646
1546	For example, larger servers often run out of file descriptors (because	1647	For example, larger servers often run out of file descriptors (because
1547	of resource limits), causing C<accept> to fail with C<ENFILE> but not	1648	of resource limits), causing C<accept> to fail with C<ENFILE> but not
1548	rejecting the connection, leading to libev signalling readiness on	1649	rejecting the connection, leading to libev signalling readiness on
…		…
1614	...	1715	...
1615	struct ev_loop *loop = ev_default_init (0);	1716	struct ev_loop *loop = ev_default_init (0);
1616	ev_io stdin_readable;	1717	ev_io stdin_readable;
1617	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1718	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1618	ev_io_start (loop, &stdin_readable);	1719	ev_io_start (loop, &stdin_readable);
1619	ev_loop (loop, 0);	1720	ev_run (loop, 0);
1620		1721
1621		1722
1622	=head2 C<ev_timer> - relative and optionally repeating timeouts	1723	=head2 C<ev_timer> - relative and optionally repeating timeouts
1623		1724
1624	Timer watchers are simple relative timers that generate an event after a	1725	Timer watchers are simple relative timers that generate an event after a
…		…
1633	The callback is guaranteed to be invoked only I<after> its timeout has	1734	The callback is guaranteed to be invoked only I<after> its timeout has
1634	passed (not I<at>, so on systems with very low-resolution clocks this	1735	passed (not I<at>, so on systems with very low-resolution clocks this
1635	might introduce a small delay). If multiple timers become ready during the	1736	might introduce a small delay). If multiple timers become ready during the
1636	same loop iteration then the ones with earlier time-out values are invoked	1737	same loop iteration then the ones with earlier time-out values are invoked
1637	before ones of the same priority with later time-out values (but this is	1738	before ones of the same priority with later time-out values (but this is
1638	no longer true when a callback calls C<ev_loop> recursively).	1739	no longer true when a callback calls C<ev_run> recursively).
1639		1740
1640	=head3 Be smart about timeouts	1741	=head3 Be smart about timeouts
1641		1742
1642	Many real-world problems involve some kind of timeout, usually for error	1743	Many real-world problems involve some kind of timeout, usually for error
1643	recovery. A typical example is an HTTP request - if the other side hangs,	1744	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1729	ev_tstamp timeout = last_activity + 60.;	1830	ev_tstamp timeout = last_activity + 60.;
1730		1831
1731	// if last_activity + 60. is older than now, we did time out	1832	// if last_activity + 60. is older than now, we did time out
1732	if (timeout < now)	1833	if (timeout < now)
1733	{	1834	{
1734	// timeout occured, take action	1835	// timeout occurred, take action
1735	}	1836	}
1736	else	1837	else
1737	{	1838	{
1738	// callback was invoked, but there was some activity, re-arm	1839	// callback was invoked, but there was some activity, re-arm
1739	// the watcher to fire in last_activity + 60, which is	1840	// the watcher to fire in last_activity + 60, which is
…		…
1766	callback (loop, timer, EV_TIMER);	1867	callback (loop, timer, EV_TIMER);
1767		1868
1768	And when there is some activity, simply store the current time in	1869	And when there is some activity, simply store the current time in
1769	C<last_activity>, no libev calls at all:	1870	C<last_activity>, no libev calls at all:
1770		1871
1771	last_actiivty = ev_now (loop);	1872	last_activity = ev_now (loop);
1772		1873
1773	This technique is slightly more complex, but in most cases where the	1874	This technique is slightly more complex, but in most cases where the
1774	time-out is unlikely to be triggered, much more efficient.	1875	time-out is unlikely to be triggered, much more efficient.
1775		1876
1776	Changing the timeout is trivial as well (if it isn't hard-coded in the	1877	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1814		1915
1815	=head3 The special problem of time updates	1916	=head3 The special problem of time updates
1816		1917
1817	Establishing the current time is a costly operation (it usually takes at	1918	Establishing the current time is a costly operation (it usually takes at
1818	least two system calls): EV therefore updates its idea of the current	1919	least two system calls): EV therefore updates its idea of the current
1819	time only before and after C<ev_loop> collects new events, which causes a	1920	time only before and after C<ev_run> collects new events, which causes a
1820	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1921	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1821	lots of events in one iteration.	1922	lots of events in one iteration.
1822		1923
1823	The relative timeouts are calculated relative to the C<ev_now ()>	1924	The relative timeouts are calculated relative to the C<ev_now ()>
1824	time. This is usually the right thing as this timestamp refers to the time	1925	time. This is usually the right thing as this timestamp refers to the time
…		…
1941	}	2042	}
1942		2043
1943	ev_timer mytimer;	2044	ev_timer mytimer;
1944	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2045	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1945	ev_timer_again (&mytimer); /* start timer */	2046	ev_timer_again (&mytimer); /* start timer */
1946	ev_loop (loop, 0);	2047	ev_run (loop, 0);
1947		2048
1948	// and in some piece of code that gets executed on any "activity":	2049	// and in some piece of code that gets executed on any "activity":
1949	// reset the timeout to start ticking again at 10 seconds	2050	// reset the timeout to start ticking again at 10 seconds
1950	ev_timer_again (&mytimer);	2051	ev_timer_again (&mytimer);
1951		2052
…		…
1977		2078
1978	As with timers, the callback is guaranteed to be invoked only when the	2079	As with timers, the callback is guaranteed to be invoked only when the
1979	point in time where it is supposed to trigger has passed. If multiple	2080	point in time where it is supposed to trigger has passed. If multiple
1980	timers become ready during the same loop iteration then the ones with	2081	timers become ready during the same loop iteration then the ones with
1981	earlier time-out values are invoked before ones with later time-out values	2082	earlier time-out values are invoked before ones with later time-out values
1982	(but this is no longer true when a callback calls C<ev_loop> recursively).	2083	(but this is no longer true when a callback calls C<ev_run> recursively).
1983		2084
1984	=head3 Watcher-Specific Functions and Data Members	2085	=head3 Watcher-Specific Functions and Data Members
1985		2086
1986	=over 4	2087	=over 4
1987		2088
…		…
2115	Example: Call a callback every hour, or, more precisely, whenever the	2216	Example: Call a callback every hour, or, more precisely, whenever the
2116	system time is divisible by 3600. The callback invocation times have	2217	system time is divisible by 3600. The callback invocation times have
2117	potentially a lot of jitter, but good long-term stability.	2218	potentially a lot of jitter, but good long-term stability.
2118		2219
2119	static void	2220	static void
2120	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2221	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
2121	{	2222	{
2122	... its now a full hour (UTC, or TAI or whatever your clock follows)	2223	... its now a full hour (UTC, or TAI or whatever your clock follows)
2123	}	2224	}
2124		2225
2125	ev_periodic hourly_tick;	2226	ev_periodic hourly_tick;
…		…
2225	Example: Try to exit cleanly on SIGINT.	2326	Example: Try to exit cleanly on SIGINT.
2226		2327
2227	static void	2328	static void
2228	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2329	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2229	{	2330	{
2230	ev_unloop (loop, EVUNLOOP_ALL);	2331	ev_break (loop, EVBREAK_ALL);
2231	}	2332	}
2232		2333
2233	ev_signal signal_watcher;	2334	ev_signal signal_watcher;
2234	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2335	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2235	ev_signal_start (loop, &signal_watcher);	2336	ev_signal_start (loop, &signal_watcher);
…		…
2621		2722
2622	Prepare and check watchers are usually (but not always) used in pairs:	2723	Prepare and check watchers are usually (but not always) used in pairs:
2623	prepare watchers get invoked before the process blocks and check watchers	2724	prepare watchers get invoked before the process blocks and check watchers
2624	afterwards.	2725	afterwards.
2625		2726
2626	You I<must not> call C<ev_loop> or similar functions that enter	2727	You I<must not> call C<ev_run> or similar functions that enter
2627	the current event loop from either C<ev_prepare> or C<ev_check>	2728	the current event loop from either C<ev_prepare> or C<ev_check>
2628	watchers. Other loops than the current one are fine, however. The	2729	watchers. Other loops than the current one are fine, however. The
2629	rationale behind this is that you do not need to check for recursion in	2730	rationale behind this is that you do not need to check for recursion in
2630	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2731	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2631	C<ev_check> so if you have one watcher of each kind they will always be	2732	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2799		2900
2800	if (timeout >= 0)	2901	if (timeout >= 0)
2801	// create/start timer	2902	// create/start timer
2802		2903
2803	// poll	2904	// poll
2804	ev_loop (EV_A_ 0);	2905	ev_run (EV_A_ 0);
2805		2906
2806	// stop timer again	2907	// stop timer again
2807	if (timeout >= 0)	2908	if (timeout >= 0)
2808	ev_timer_stop (EV_A_ &to);	2909	ev_timer_stop (EV_A_ &to);
2809		2910
…		…
2887	if you do not want that, you need to temporarily stop the embed watcher).	2988	if you do not want that, you need to temporarily stop the embed watcher).
2888		2989
2889	=item ev_embed_sweep (loop, ev_embed *)	2990	=item ev_embed_sweep (loop, ev_embed *)
2890		2991
2891	Make a single, non-blocking sweep over the embedded loop. This works	2992	Make a single, non-blocking sweep over the embedded loop. This works
2892	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2993	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2893	appropriate way for embedded loops.	2994	appropriate way for embedded loops.
2894		2995
2895	=item struct ev_loop *other [read-only]	2996	=item struct ev_loop *other [read-only]
2896		2997
2897	The embedded event loop.	2998	The embedded event loop.
…		…
2957	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3058	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2958	handlers will be invoked, too, of course.	3059	handlers will be invoked, too, of course.
2959		3060
2960	=head3 The special problem of life after fork - how is it possible?	3061	=head3 The special problem of life after fork - how is it possible?
2961		3062
2962	Most uses of C<fork()> consist of forking, then some simple calls to ste	3063	Most uses of C<fork()> consist of forking, then some simple calls to set
2963	up/change the process environment, followed by a call to C<exec()>. This	3064	up/change the process environment, followed by a call to C<exec()>. This
2964	sequence should be handled by libev without any problems.	3065	sequence should be handled by libev without any problems.
2965		3066
2966	This changes when the application actually wants to do event handling	3067	This changes when the application actually wants to do event handling
2967	in the child, or both parent in child, in effect "continuing" after the	3068	in the child, or both parent in child, in effect "continuing" after the
…		…
2983	disadvantage of having to use multiple event loops (which do not support	3084	disadvantage of having to use multiple event loops (which do not support
2984	signal watchers).	3085	signal watchers).
2985		3086
2986	When this is not possible, or you want to use the default loop for	3087	When this is not possible, or you want to use the default loop for
2987	other reasons, then in the process that wants to start "fresh", call	3088	other reasons, then in the process that wants to start "fresh", call
2988	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3089	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2989	the default loop will "orphan" (not stop) all registered watchers, so you	3090	Destroying the default loop will "orphan" (not stop) all registered
2990	have to be careful not to execute code that modifies those watchers. Note	3091	watchers, so you have to be careful not to execute code that modifies
2991	also that in that case, you have to re-register any signal watchers.	3092	those watchers. Note also that in that case, you have to re-register any
		3093	signal watchers.
2992		3094
2993	=head3 Watcher-Specific Functions and Data Members	3095	=head3 Watcher-Specific Functions and Data Members
2994		3096
2995	=over 4	3097	=over 4
2996		3098
2997	=item ev_fork_init (ev_signal *, callback)	3099	=item ev_fork_init (ev_fork *, callback)
2998		3100
2999	Initialises and configures the fork watcher - it has no parameters of any	3101	Initialises and configures the fork watcher - it has no parameters of any
3000	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,	3102	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3001	believe me.	3103	really.
3002		3104
3003	=back	3105	=back
3004		3106
3005		3107
		3108	=head2 C<ev_cleanup> - even the best things end
		3109
		3110	Cleanup watchers are called just before the event loop is being destroyed
		3111	by a call to C<ev_loop_destroy>.
		3112
		3113	While there is no guarantee that the event loop gets destroyed, cleanup
		3114	watchers provide a convenient method to install cleanup hooks for your
		3115	program, worker threads and so on - you just to make sure to destroy the
		3116	loop when you want them to be invoked.
		3117
		3118	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3119	all other watchers, they do not keep a reference to the event loop (which
		3120	makes a lot of sense if you think about it). Like all other watchers, you
		3121	can call libev functions in the callback, except C<ev_cleanup_start>.
		3122
		3123	=head3 Watcher-Specific Functions and Data Members
		3124
		3125	=over 4
		3126
		3127	=item ev_cleanup_init (ev_cleanup *, callback)
		3128
		3129	Initialises and configures the cleanup watcher - it has no parameters of
		3130	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3131	pointless, I assure you.
		3132
		3133	=back
		3134
		3135	Example: Register an atexit handler to destroy the default loop, so any
		3136	cleanup functions are called.
		3137
		3138	static void
		3139	program_exits (void)
		3140	{
		3141	ev_loop_destroy (EV_DEFAULT_UC);
		3142	}
		3143
		3144	...
		3145	atexit (program_exits);
		3146
		3147
3006	=head2 C<ev_async> - how to wake up another event loop	3148	=head2 C<ev_async> - how to wake up an event loop
3007		3149
3008	In general, you cannot use an C<ev_loop> from multiple threads or other	3150	In general, you cannot use an C<ev_run> from multiple threads or other
3009	asynchronous sources such as signal handlers (as opposed to multiple event	3151	asynchronous sources such as signal handlers (as opposed to multiple event
3010	loops - those are of course safe to use in different threads).	3152	loops - those are of course safe to use in different threads).
3011		3153
3012	Sometimes, however, you need to wake up another event loop you do not	3154	Sometimes, however, you need to wake up an event loop you do not control,
3013	control, for example because it belongs to another thread. This is what	3155	for example because it belongs to another thread. This is what C<ev_async>
3014	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3156	watchers do: as long as the C<ev_async> watcher is active, you can signal
3015	can signal it by calling C<ev_async_send>, which is thread- and signal	3157	it by calling C<ev_async_send>, which is thread- and signal safe.
3016	safe.
3017		3158
3018	This functionality is very similar to C<ev_signal> watchers, as signals,	3159	This functionality is very similar to C<ev_signal> watchers, as signals,
3019	too, are asynchronous in nature, and signals, too, will be compressed	3160	too, are asynchronous in nature, and signals, too, will be compressed
3020	(i.e. the number of callback invocations may be less than the number of	3161	(i.e. the number of callback invocations may be less than the number of
3021	C<ev_async_sent> calls).	3162	C<ev_async_sent> calls).
…		…
3333	myclass obj;	3474	myclass obj;
3334	ev::io iow;	3475	ev::io iow;
3335	iow.set <myclass, &myclass::io_cb> (&obj);	3476	iow.set <myclass, &myclass::io_cb> (&obj);
3336		3477
3337	=item w->set (object *)	3478	=item w->set (object *)
3338
3339	This is an B<experimental> feature that might go away in a future version.
3340		3479
3341	This is a variation of a method callback - leaving out the method to call	3480	This is a variation of a method callback - leaving out the method to call
3342	will default the method to C<operator ()>, which makes it possible to use	3481	will default the method to C<operator ()>, which makes it possible to use
3343	functor objects without having to manually specify the C<operator ()> all	3482	functor objects without having to manually specify the C<operator ()> all
3344	the time. Incidentally, you can then also leave out the template argument	3483	the time. Incidentally, you can then also leave out the template argument
…		…
3384	Associates a different C<struct ev_loop> with this watcher. You can only	3523	Associates a different C<struct ev_loop> with this watcher. You can only
3385	do this when the watcher is inactive (and not pending either).	3524	do this when the watcher is inactive (and not pending either).
3386		3525
3387	=item w->set ([arguments])	3526	=item w->set ([arguments])
3388		3527
3389	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3528	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3390	called at least once. Unlike the C counterpart, an active watcher gets	3529	method or a suitable start method must be called at least once. Unlike the
3391	automatically stopped and restarted when reconfiguring it with this	3530	C counterpart, an active watcher gets automatically stopped and restarted
3392	method.	3531	when reconfiguring it with this method.
3393		3532
3394	=item w->start ()	3533	=item w->start ()
3395		3534
3396	Starts the watcher. Note that there is no C<loop> argument, as the	3535	Starts the watcher. Note that there is no C<loop> argument, as the
3397	constructor already stores the event loop.	3536	constructor already stores the event loop.
3398		3537
		3538	=item w->start ([arguments])
		3539
		3540	Instead of calling C<set> and C<start> methods separately, it is often
		3541	convenient to wrap them in one call. Uses the same type of arguments as
		3542	the configure C<set> method of the watcher.
		3543
3399	=item w->stop ()	3544	=item w->stop ()
3400		3545
3401	Stops the watcher if it is active. Again, no C<loop> argument.	3546	Stops the watcher if it is active. Again, no C<loop> argument.
3402		3547
3403	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3548	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3415		3560
3416	=back	3561	=back
3417		3562
3418	=back	3563	=back
3419		3564
3420	Example: Define a class with an IO and idle watcher, start one of them in	3565	Example: Define a class with two I/O and idle watchers, start the I/O
3421	the constructor.	3566	watchers in the constructor.
3422		3567
3423	class myclass	3568	class myclass
3424	{	3569	{
3425	ev::io io ; void io_cb (ev::io &w, int revents);	3570	ev::io io ; void io_cb (ev::io &w, int revents);
		3571	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3426	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3572	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3427		3573
3428	myclass (int fd)	3574	myclass (int fd)
3429	{	3575	{
3430	io .set <myclass, &myclass::io_cb > (this);	3576	io .set <myclass, &myclass::io_cb > (this);
		3577	io2 .set <myclass, &myclass::io2_cb > (this);
3431	idle.set <myclass, &myclass::idle_cb> (this);	3578	idle.set <myclass, &myclass::idle_cb> (this);
3432		3579
3433	io.start (fd, ev::READ);	3580	io.set (fd, ev::WRITE); // configure the watcher
		3581	io.start (); // start it whenever convenient
		3582
		3583	io2.start (fd, ev::READ); // set + start in one call
3434	}	3584	}
3435	};	3585	};
3436		3586
3437		3587
3438	=head1 OTHER LANGUAGE BINDINGS	3588	=head1 OTHER LANGUAGE BINDINGS
…		…
3512	loop argument"). The C<EV_A> form is used when this is the sole argument,	3662	loop argument"). The C<EV_A> form is used when this is the sole argument,
3513	C<EV_A_> is used when other arguments are following. Example:	3663	C<EV_A_> is used when other arguments are following. Example:
3514		3664
3515	ev_unref (EV_A);	3665	ev_unref (EV_A);
3516	ev_timer_add (EV_A_ watcher);	3666	ev_timer_add (EV_A_ watcher);
3517	ev_loop (EV_A_ 0);	3667	ev_run (EV_A_ 0);
3518		3668
3519	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3669	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3520	which is often provided by the following macro.	3670	which is often provided by the following macro.
3521		3671
3522	=item C<EV_P>, C<EV_P_>	3672	=item C<EV_P>, C<EV_P_>
…		…
3562	}	3712	}
3563		3713
3564	ev_check check;	3714	ev_check check;
3565	ev_check_init (&check, check_cb);	3715	ev_check_init (&check, check_cb);
3566	ev_check_start (EV_DEFAULT_ &check);	3716	ev_check_start (EV_DEFAULT_ &check);
3567	ev_loop (EV_DEFAULT_ 0);	3717	ev_run (EV_DEFAULT_ 0);
3568		3718
3569	=head1 EMBEDDING	3719	=head1 EMBEDDING
3570		3720
3571	Libev can (and often is) directly embedded into host	3721	Libev can (and often is) directly embedded into host
3572	applications. Examples of applications that embed it include the Deliantra	3722	applications. Examples of applications that embed it include the Deliantra
…		…
3657	define before including (or compiling) any of its files. The default in	3807	define before including (or compiling) any of its files. The default in
3658	the absence of autoconf is documented for every option.	3808	the absence of autoconf is documented for every option.
3659		3809
3660	Symbols marked with "(h)" do not change the ABI, and can have different	3810	Symbols marked with "(h)" do not change the ABI, and can have different
3661	values when compiling libev vs. including F<ev.h>, so it is permissible	3811	values when compiling libev vs. including F<ev.h>, so it is permissible
3662	to redefine them before including F<ev.h> without breakign compatibility	3812	to redefine them before including F<ev.h> without breaking compatibility
3663	to a compiled library. All other symbols change the ABI, which means all	3813	to a compiled library. All other symbols change the ABI, which means all
3664	users of libev and the libev code itself must be compiled with compatible	3814	users of libev and the libev code itself must be compiled with compatible
3665	settings.	3815	settings.
3666		3816
3667	=over 4	3817	=over 4
		3818
		3819	=item EV_COMPAT3 (h)
		3820
		3821	Backwards compatibility is a major concern for libev. This is why this
		3822	release of libev comes with wrappers for the functions and symbols that
		3823	have been renamed between libev version 3 and 4.
		3824
		3825	You can disable these wrappers (to test compatibility with future
		3826	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3827	sources. This has the additional advantage that you can drop the C<struct>
		3828	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3829	typedef in that case.
		3830
		3831	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3832	and in some even more future version the compatibility code will be
		3833	removed completely.
3668		3834
3669	=item EV_STANDALONE (h)	3835	=item EV_STANDALONE (h)
3670		3836
3671	Must always be C<1> if you do not use autoconf configuration, which	3837	Must always be C<1> if you do not use autoconf configuration, which
3672	keeps libev from including F<config.h>, and it also defines dummy	3838	keeps libev from including F<config.h>, and it also defines dummy
…		…
3879	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,	4045	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
3880	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.	4046	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3881		4047
3882	If undefined or defined to be C<1> (and the platform supports it), then	4048	If undefined or defined to be C<1> (and the platform supports it), then
3883	the respective watcher type is supported. If defined to be C<0>, then it	4049	the respective watcher type is supported. If defined to be C<0>, then it
3884	is not. Disabling watcher types mainly saves codesize.	4050	is not. Disabling watcher types mainly saves code size.
3885		4051
3886	=item EV_FEATURES	4052	=item EV_FEATURES
3887		4053
3888	If you need to shave off some kilobytes of code at the expense of some	4054	If you need to shave off some kilobytes of code at the expense of some
3889	speed (but with the full API), you can define this symbol to request	4055	speed (but with the full API), you can define this symbol to request
…		…
3909		4075
3910	=item C<1> - faster/larger code	4076	=item C<1> - faster/larger code
3911		4077
3912	Use larger code to speed up some operations.	4078	Use larger code to speed up some operations.
3913		4079
3914	Currently this is used to override some inlining decisions (enlarging the roughly	4080	Currently this is used to override some inlining decisions (enlarging the
3915	30% code size on amd64.	4081	code size by roughly 30% on amd64).
3916		4082
3917	When optimising for size, use of compiler flags such as C<-Os> with	4083	When optimising for size, use of compiler flags such as C<-Os> with
3918	gcc recommended, as well as C<-DNDEBUG>, as libev contains a number of	4084	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
3919	assertions.	4085	assertions.
3920		4086
3921	=item C<2> - faster/larger data structures	4087	=item C<2> - faster/larger data structures
3922		4088
3923	Replaces the small 2-heap for timer management by a faster 4-heap, larger	4089	Replaces the small 2-heap for timer management by a faster 4-heap, larger
3924	hash table sizes and so on. This will usually further increase codesize	4090	hash table sizes and so on. This will usually further increase code size
3925	and can additionally have an effect on the size of data structures at	4091	and can additionally have an effect on the size of data structures at
3926	runtime.	4092	runtime.
3927		4093
3928	=item C<4> - full API configuration	4094	=item C<4> - full API configuration
3929		4095
…		…
3966	I/O watcher then might come out at only 5Kb.	4132	I/O watcher then might come out at only 5Kb.
3967		4133
3968	=item EV_AVOID_STDIO	4134	=item EV_AVOID_STDIO
3969		4135
3970	If this is set to C<1> at compiletime, then libev will avoid using stdio	4136	If this is set to C<1> at compiletime, then libev will avoid using stdio
3971	functions (printf, scanf, perror etc.). This will increase the codesize	4137	functions (printf, scanf, perror etc.). This will increase the code size
3972	somewhat, but if your program doesn't otherwise depend on stdio and your	4138	somewhat, but if your program doesn't otherwise depend on stdio and your
3973	libc allows it, this avoids linking in the stdio library which is quite	4139	libc allows it, this avoids linking in the stdio library which is quite
3974	big.	4140	big.
3975		4141
3976	Note that error messages might become less precise when this option is	4142	Note that error messages might become less precise when this option is
…		…
3980		4146
3981	The highest supported signal number, +1 (or, the number of	4147	The highest supported signal number, +1 (or, the number of
3982	signals): Normally, libev tries to deduce the maximum number of signals	4148	signals): Normally, libev tries to deduce the maximum number of signals
3983	automatically, but sometimes this fails, in which case it can be	4149	automatically, but sometimes this fails, in which case it can be
3984	specified. Also, using a lower number than detected (C<32> should be	4150	specified. Also, using a lower number than detected (C<32> should be
3985	good for about any system in existance) can save some memory, as libev	4151	good for about any system in existence) can save some memory, as libev
3986	statically allocates some 12-24 bytes per signal number.	4152	statically allocates some 12-24 bytes per signal number.
3987		4153
3988	=item EV_PID_HASHSIZE	4154	=item EV_PID_HASHSIZE
3989		4155
3990	C<ev_child> watchers use a small hash table to distribute workload by	4156	C<ev_child> watchers use a small hash table to distribute workload by
…		…
4022	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4188	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4023	will be C<0>.	4189	will be C<0>.
4024		4190
4025	=item EV_VERIFY	4191	=item EV_VERIFY
4026		4192
4027	Controls how much internal verification (see C<ev_loop_verify ()>) will	4193	Controls how much internal verification (see C<ev_verify ()>) will
4028	be done: If set to C<0>, no internal verification code will be compiled	4194	be done: If set to C<0>, no internal verification code will be compiled
4029	in. If set to C<1>, then verification code will be compiled in, but not	4195	in. If set to C<1>, then verification code will be compiled in, but not
4030	called. If set to C<2>, then the internal verification code will be	4196	called. If set to C<2>, then the internal verification code will be
4031	called once per loop, which can slow down libev. If set to C<3>, then the	4197	called once per loop, which can slow down libev. If set to C<3>, then the
4032	verification code will be called very frequently, which will slow down	4198	verification code will be called very frequently, which will slow down
…		…
4036	will be C<0>.	4202	will be C<0>.
4037		4203
4038	=item EV_COMMON	4204	=item EV_COMMON
4039		4205
4040	By default, all watchers have a C<void *data> member. By redefining	4206	By default, all watchers have a C<void *data> member. By redefining
4041	this macro to a something else you can include more and other types of	4207	this macro to something else you can include more and other types of
4042	members. You have to define it each time you include one of the files,	4208	members. You have to define it each time you include one of the files,
4043	though, and it must be identical each time.	4209	though, and it must be identical each time.
4044		4210
4045	For example, the perl EV module uses something like this:	4211	For example, the perl EV module uses something like this:
4046		4212
…		…
4247	userdata *u = ev_userdata (EV_A);	4413	userdata *u = ev_userdata (EV_A);
4248	pthread_mutex_lock (&u->lock);	4414	pthread_mutex_lock (&u->lock);
4249	}	4415	}
4250		4416
4251	The event loop thread first acquires the mutex, and then jumps straight	4417	The event loop thread first acquires the mutex, and then jumps straight
4252	into C<ev_loop>:	4418	into C<ev_run>:
4253		4419
4254	void *	4420	void *
4255	l_run (void *thr_arg)	4421	l_run (void *thr_arg)
4256	{	4422	{
4257	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4423	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4258		4424
4259	l_acquire (EV_A);	4425	l_acquire (EV_A);
4260	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4426	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4261	ev_loop (EV_A_ 0);	4427	ev_run (EV_A_ 0);
4262	l_release (EV_A);	4428	l_release (EV_A);
4263		4429
4264	return 0;	4430	return 0;
4265	}	4431	}
4266		4432
…		…
4318		4484
4319	=head3 COROUTINES	4485	=head3 COROUTINES
4320		4486
4321	Libev is very accommodating to coroutines ("cooperative threads"):	4487	Libev is very accommodating to coroutines ("cooperative threads"):
4322	libev fully supports nesting calls to its functions from different	4488	libev fully supports nesting calls to its functions from different
4323	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4489	coroutines (e.g. you can call C<ev_run> on the same loop from two
4324	different coroutines, and switch freely between both coroutines running	4490	different coroutines, and switch freely between both coroutines running
4325	the loop, as long as you don't confuse yourself). The only exception is	4491	the loop, as long as you don't confuse yourself). The only exception is
4326	that you must not do this from C<ev_periodic> reschedule callbacks.	4492	that you must not do this from C<ev_periodic> reschedule callbacks.
4327		4493
4328	Care has been taken to ensure that libev does not keep local state inside	4494	Care has been taken to ensure that libev does not keep local state inside
4329	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4495	C<ev_run>, and other calls do not usually allow for coroutine switches as
4330	they do not call any callbacks.	4496	they do not call any callbacks.
4331		4497
4332	=head2 COMPILER WARNINGS	4498	=head2 COMPILER WARNINGS
4333		4499
4334	Depending on your compiler and compiler settings, you might get no or a	4500	Depending on your compiler and compiler settings, you might get no or a
…		…
4345	maintainable.	4511	maintainable.
4346		4512
4347	And of course, some compiler warnings are just plain stupid, or simply	4513	And of course, some compiler warnings are just plain stupid, or simply
4348	wrong (because they don't actually warn about the condition their message	4514	wrong (because they don't actually warn about the condition their message
4349	seems to warn about). For example, certain older gcc versions had some	4515	seems to warn about). For example, certain older gcc versions had some
4350	warnings that resulted an extreme number of false positives. These have	4516	warnings that resulted in an extreme number of false positives. These have
4351	been fixed, but some people still insist on making code warn-free with	4517	been fixed, but some people still insist on making code warn-free with
4352	such buggy versions.	4518	such buggy versions.
4353		4519
4354	While libev is written to generate as few warnings as possible,	4520	While libev is written to generate as few warnings as possible,
4355	"warn-free" code is not a goal, and it is recommended not to build libev	4521	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4391	I suggest using suppression lists.	4557	I suggest using suppression lists.
4392		4558
4393		4559
4394	=head1 PORTABILITY NOTES	4560	=head1 PORTABILITY NOTES
4395		4561
		4562	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4563
		4564	GNU/Linux is the only common platform that supports 64 bit file/large file
		4565	interfaces but I<disables> them by default.
		4566
		4567	That means that libev compiled in the default environment doesn't support
		4568	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4569
		4570	Unfortunately, many programs try to work around this GNU/Linux issue
		4571	by enabling the large file API, which makes them incompatible with the
		4572	standard libev compiled for their system.
		4573
		4574	Likewise, libev cannot enable the large file API itself as this would
		4575	suddenly make it incompatible to the default compile time environment,
		4576	i.e. all programs not using special compile switches.
		4577
		4578	=head2 OS/X AND DARWIN BUGS
		4579
		4580	The whole thing is a bug if you ask me - basically any system interface
		4581	you touch is broken, whether it is locales, poll, kqueue or even the
		4582	OpenGL drivers.
		4583
		4584	=head3 C<kqueue> is buggy
		4585
		4586	The kqueue syscall is broken in all known versions - most versions support
		4587	only sockets, many support pipes.
		4588
		4589	Libev tries to work around this by not using C<kqueue> by default on this
		4590	rotten platform, but of course you can still ask for it when creating a
		4591	loop - embedding a socket-only kqueue loop into a select-based one is
		4592	probably going to work well.
		4593
		4594	=head3 C<poll> is buggy
		4595
		4596	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4597	implementation by something calling C<kqueue> internally around the 10.5.6
		4598	release, so now C<kqueue> I<and> C<poll> are broken.
		4599
		4600	Libev tries to work around this by not using C<poll> by default on
		4601	this rotten platform, but of course you can still ask for it when creating
		4602	a loop.
		4603
		4604	=head3 C<select> is buggy
		4605
		4606	All that's left is C<select>, and of course Apple found a way to fuck this
		4607	one up as well: On OS/X, C<select> actively limits the number of file
		4608	descriptors you can pass in to 1024 - your program suddenly crashes when
		4609	you use more.
		4610
		4611	There is an undocumented "workaround" for this - defining
		4612	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4613	work on OS/X.
		4614
		4615	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4616
		4617	=head3 C<errno> reentrancy
		4618
		4619	The default compile environment on Solaris is unfortunately so
		4620	thread-unsafe that you can't even use components/libraries compiled
		4621	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4622	defined by default. A valid, if stupid, implementation choice.
		4623
		4624	If you want to use libev in threaded environments you have to make sure
		4625	it's compiled with C<_REENTRANT> defined.
		4626
		4627	=head3 Event port backend
		4628
		4629	The scalable event interface for Solaris is called "event
		4630	ports". Unfortunately, this mechanism is very buggy in all major
		4631	releases. If you run into high CPU usage, your program freezes or you get
		4632	a large number of spurious wakeups, make sure you have all the relevant
		4633	and latest kernel patches applied. No, I don't know which ones, but there
		4634	are multiple ones to apply, and afterwards, event ports actually work
		4635	great.
		4636
		4637	If you can't get it to work, you can try running the program by setting
		4638	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4639	C<select> backends.
		4640
		4641	=head2 AIX POLL BUG
		4642
		4643	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4644	this by trying to avoid the poll backend altogether (i.e. it's not even
		4645	compiled in), which normally isn't a big problem as C<select> works fine
		4646	with large bitsets on AIX, and AIX is dead anyway.
		4647
4396	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4648	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4649
		4650	=head3 General issues
4397		4651
4398	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4652	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4399	requires, and its I/O model is fundamentally incompatible with the POSIX	4653	requires, and its I/O model is fundamentally incompatible with the POSIX
4400	model. Libev still offers limited functionality on this platform in	4654	model. Libev still offers limited functionality on this platform in
4401	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4655	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4402	descriptors. This only applies when using Win32 natively, not when using	4656	descriptors. This only applies when using Win32 natively, not when using
4403	e.g. cygwin.	4657	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4658	as every compielr comes with a slightly differently broken/incompatible
		4659	environment.
4404		4660
4405	Lifting these limitations would basically require the full	4661	Lifting these limitations would basically require the full
4406	re-implementation of the I/O system. If you are into these kinds of	4662	re-implementation of the I/O system. If you are into this kind of thing,
4407	things, then note that glib does exactly that for you in a very portable	4663	then note that glib does exactly that for you in a very portable way (note
4408	way (note also that glib is the slowest event library known to man).	4664	also that glib is the slowest event library known to man).
4409		4665
4410	There is no supported compilation method available on windows except	4666	There is no supported compilation method available on windows except
4411	embedding it into other applications.	4667	embedding it into other applications.
4412		4668
4413	Sensible signal handling is officially unsupported by Microsoft - libev	4669	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4441	you do I<not> compile the F<ev.c> or any other embedded source files!):	4697	you do I<not> compile the F<ev.c> or any other embedded source files!):
4442		4698
4443	#include "evwrap.h"	4699	#include "evwrap.h"
4444	#include "ev.c"	4700	#include "ev.c"
4445		4701
4446	=over 4
4447
4448	=item The winsocket select function	4702	=head3 The winsocket C<select> function
4449		4703
4450	The winsocket C<select> function doesn't follow POSIX in that it	4704	The winsocket C<select> function doesn't follow POSIX in that it
4451	requires socket I<handles> and not socket I<file descriptors> (it is	4705	requires socket I<handles> and not socket I<file descriptors> (it is
4452	also extremely buggy). This makes select very inefficient, and also	4706	also extremely buggy). This makes select very inefficient, and also
4453	requires a mapping from file descriptors to socket handles (the Microsoft	4707	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4462	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4716	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4463		4717
4464	Note that winsockets handling of fd sets is O(n), so you can easily get a	4718	Note that winsockets handling of fd sets is O(n), so you can easily get a
4465	complexity in the O(n²) range when using win32.	4719	complexity in the O(n²) range when using win32.
4466		4720
4467	=item Limited number of file descriptors	4721	=head3 Limited number of file descriptors
4468		4722
4469	Windows has numerous arbitrary (and low) limits on things.	4723	Windows has numerous arbitrary (and low) limits on things.
4470		4724
4471	Early versions of winsocket's select only supported waiting for a maximum	4725	Early versions of winsocket's select only supported waiting for a maximum
4472	of C<64> handles (probably owning to the fact that all windows kernels	4726	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4487	runtime libraries. This might get you to about C<512> or C<2048> sockets	4741	runtime libraries. This might get you to about C<512> or C<2048> sockets
4488	(depending on windows version and/or the phase of the moon). To get more,	4742	(depending on windows version and/or the phase of the moon). To get more,
4489	you need to wrap all I/O functions and provide your own fd management, but	4743	you need to wrap all I/O functions and provide your own fd management, but
4490	the cost of calling select (O(n²)) will likely make this unworkable.	4744	the cost of calling select (O(n²)) will likely make this unworkable.
4491		4745
4492	=back
4493
4494	=head2 PORTABILITY REQUIREMENTS	4746	=head2 PORTABILITY REQUIREMENTS
4495		4747
4496	In addition to a working ISO-C implementation and of course the	4748	In addition to a working ISO-C implementation and of course the
4497	backend-specific APIs, libev relies on a few additional extensions:	4749	backend-specific APIs, libev relies on a few additional extensions:
4498		4750
…		…
4536	watchers.	4788	watchers.
4537		4789
4538	=item C<double> must hold a time value in seconds with enough accuracy	4790	=item C<double> must hold a time value in seconds with enough accuracy
4539		4791
4540	The type C<double> is used to represent timestamps. It is required to	4792	The type C<double> is used to represent timestamps. It is required to
4541	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4793	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4542	enough for at least into the year 4000. This requirement is fulfilled by	4794	good enough for at least into the year 4000 with millisecond accuracy
		4795	(the design goal for libev). This requirement is overfulfilled by
4543	implementations implementing IEEE 754, which is basically all existing	4796	implementations using IEEE 754, which is basically all existing ones. With
4544	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4797	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4545	2200.
4546		4798
4547	=back	4799	=back
4548		4800
4549	If you know of other additional requirements drop me a note.	4801	If you know of other additional requirements drop me a note.
4550		4802
…		…
4618	involves iterating over all running async watchers or all signal numbers.	4870	involves iterating over all running async watchers or all signal numbers.
4619		4871
4620	=back	4872	=back
4621		4873
4622		4874
4623	=head1 PORTING FROM 3.X TO 4.X	4875	=head1 PORTING FROM LIBEV 3.X TO 4.X
4624		4876
4625	The major version 4 introduced some minor incompatible changes to the API.	4877	The major version 4 introduced some minor incompatible changes to the API.
4626		4878
		4879	At the moment, the C<ev.h> header file tries to implement superficial
		4880	compatibility, so most programs should still compile. Those might be
		4881	removed in later versions of libev, so better update early than late.
		4882
4627	=over 4	4883	=over 4
4628		4884
4629	=item C<EV_TIMEOUT> replaced by C<EV_TIMER> in C<revents>	4885	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
4630		4886
4631	This is a simple rename - all other watcher types use their name	4887	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
4632	as revents flag, and now C<ev_timer> does, too.
4633		4888
4634	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions	4889	ev_loop_destroy (EV_DEFAULT_UC);
4635	and continue to be present for the forseeable future, so this is mostly a	4890	ev_loop_fork (EV_DEFAULT);
4636	documentation change.	4891
		4892	=item function/symbol renames
		4893
		4894	A number of functions and symbols have been renamed:
		4895
		4896	ev_loop => ev_run
		4897	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4898	EVLOOP_ONESHOT => EVRUN_ONCE
		4899
		4900	ev_unloop => ev_break
		4901	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4902	EVUNLOOP_ONE => EVBREAK_ONE
		4903	EVUNLOOP_ALL => EVBREAK_ALL
		4904
		4905	EV_TIMEOUT => EV_TIMER
		4906
		4907	ev_loop_count => ev_iteration
		4908	ev_loop_depth => ev_depth
		4909	ev_loop_verify => ev_verify
		4910
		4911	Most functions working on C<struct ev_loop> objects don't have an
		4912	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4913	associated constants have been renamed to not collide with the C<struct
		4914	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4915	as all other watcher types. Note that C<ev_loop_fork> is still called
		4916	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4917	typedef.
		4918
		4919	=item C<EV_COMPAT3> backwards compatibility mechanism
		4920
		4921	The backward compatibility mechanism can be controlled by
		4922	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4923	section.
4637		4924
4638	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4925	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4639		4926
4640	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4927	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4641	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4928	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
…		…
4648		4935
4649	=over 4	4936	=over 4
4650		4937
4651	=item active	4938	=item active
4652		4939
4653	A watcher is active as long as it has been started (has been attached to	4940	A watcher is active as long as it has been started and not yet stopped.
4654	an event loop) but not yet stopped (disassociated from the event loop).	4941	See L<WATCHER STATES> for details.
4655		4942
4656	=item application	4943	=item application
4657		4944
4658	In this document, an application is whatever is using libev.	4945	In this document, an application is whatever is using libev.
		4946
		4947	=item backend
		4948
		4949	The part of the code dealing with the operating system interfaces.
4659		4950
4660	=item callback	4951	=item callback
4661		4952
4662	The address of a function that is called when some event has been	4953	The address of a function that is called when some event has been
4663	detected. Callbacks are being passed the event loop, the watcher that	4954	detected. Callbacks are being passed the event loop, the watcher that
4664	received the event, and the actual event bitset.	4955	received the event, and the actual event bitset.
4665		4956
4666	=item callback invocation	4957	=item callback/watcher invocation
4667		4958
4668	The act of calling the callback associated with a watcher.	4959	The act of calling the callback associated with a watcher.
4669		4960
4670	=item event	4961	=item event
4671		4962
…		…
4690	The model used to describe how an event loop handles and processes	4981	The model used to describe how an event loop handles and processes
4691	watchers and events.	4982	watchers and events.
4692		4983
4693	=item pending	4984	=item pending
4694		4985
4695	A watcher is pending as soon as the corresponding event has been detected,	4986	A watcher is pending as soon as the corresponding event has been
4696	and stops being pending as soon as the watcher will be invoked or its	4987	detected. See L<WATCHER STATES> for details.
4697	pending status is explicitly cleared by the application.
4698
4699	A watcher can be pending, but not active. Stopping a watcher also clears
4700	its pending status.
4701		4988
4702	=item real time	4989	=item real time
4703		4990
4704	The physical time that is observed. It is apparently strictly monotonic :)	4991	The physical time that is observed. It is apparently strictly monotonic :)
4705		4992
…		…
4712	=item watcher	4999	=item watcher
4713		5000
4714	A data structure that describes interest in certain events. Watchers need	5001	A data structure that describes interest in certain events. Watchers need
4715	to be started (attached to an event loop) before they can receive events.	5002	to be started (attached to an event loop) before they can receive events.
4716		5003
4717	=item watcher invocation
4718
4719	The act of calling the callback associated with a watcher.
4720
4721	=back	5004	=back
4722		5005
4723	=head1 AUTHOR	5006	=head1 AUTHOR
4724		5007
4725	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5008	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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