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Revision 1.276 by root, Tue Dec 29 13:11:00 2009 UTC vs.
Revision 1.323 by root, Sun Oct 24 18:01:26 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
…		…
370	When this flag is specified, then libev will not attempt to use the	398	When this flag is specified, then libev will not attempt to use the
371	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and	399	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and
372	testing, this flag can be useful to conserve inotify file descriptors, as	400	testing, this flag can be useful to conserve inotify file descriptors, as
373	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.	401	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
374		402
375	=item C<EVFLAG_NOSIGFD>	403	=item C<EVFLAG_SIGNALFD>
376		404
377	When this flag is specified, then libev will not attempt to use the	405	When this flag is specified, then libev will attempt to use the
378	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This is	406	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API
379	probably only useful to work around any bugs in libev. Consequently, this	407	delivers signals synchronously, which makes it both faster and might make
380	flag might go away once the signalfd functionality is considered stable,	408	it possible to get the queued signal data. It can also simplify signal
381	so it's useful mostly in environment variables and not in program code.	409	handling with threads, as long as you properly block signals in your
		410	threads that are not interested in handling them.
		411
		412	Signalfd will not be used by default as this changes your signal mask, and
		413	there are a lot of shoddy libraries and programs (glib's threadpool for
		414	example) that can't properly initialise their signal masks.
382		415
383	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	416	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
384		417
385	This is your standard select(2) backend. Not I<completely> standard, as	418	This is your standard select(2) backend. Not I<completely> standard, as
386	libev tries to roll its own fd_set with no limits on the number of fds,	419	libev tries to roll its own fd_set with no limits on the number of fds,
…		…
434	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
435	I<different> file descriptors (even already closed ones, so one cannot	468	I<different> file descriptors (even already closed ones, so one cannot
436	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
437	on SMP systems). Libev tries to counter these spurious notifications by	470	on SMP systems). Libev tries to counter these spurious notifications by
438	employing an additional generation counter and comparing that against the	471	employing an additional generation counter and comparing that against the
439	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...).
440		475
441	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
442	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
443	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
444	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
…		…
542	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,
543	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
544	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
545	()> will be tried.	580	()> will be tried.
546		581
547	Example: This is the most typical usage.
548
549	if (!ev_default_loop (0))
550	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
551
552	Example: Restrict libev to the select and poll backends, and do not allow
553	environment settings to be taken into account:
554
555	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
556
557	Example: Use whatever libev has to offer, but make sure that kqueue is
558	used if available (warning, breaks stuff, best use only with your own
559	private event loop and only if you know the OS supports your types of
560	fds):
561
562	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
563
564	=item struct ev_loop *ev_loop_new (unsigned int flags)
565
566	Similar to C<ev_default_loop>, but always creates a new event loop that is
567	always distinct from the default loop. Unlike the default loop, it cannot
568	handle signal and child watchers, and attempts to do so will be greeted by
569	undefined behaviour (or a failed assertion if assertions are enabled).
570
571	Note that this function I<is> thread-safe, and the recommended way to use
572	libev with threads is indeed to create one loop per thread, and using the
573	default loop in the "main" or "initial" thread.
574
575	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.
576		583
577	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
578	if (!epoller)	585	if (!epoller)
579	fatal ("no epoll found here, maybe it hides under your chair");	586	fatal ("no epoll found here, maybe it hides under your chair");
580		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
581	=item ev_default_destroy ()	593	=item ev_loop_destroy (loop)
582		594
583	Destroys the default loop again (frees all memory and kernel state	595	Destroys an event loop object (frees all memory and kernel state
584	etc.). None of the active event watchers will be stopped in the normal	596	etc.). None of the active event watchers will be stopped in the normal
585	sense, so e.g. C<ev_is_active> might still return true. It is your	597	sense, so e.g. C<ev_is_active> might still return true. It is your
586	responsibility to either stop all watchers cleanly yourself I<before>	598	responsibility to either stop all watchers cleanly yourself I<before>
587	calling this function, or cope with the fact afterwards (which is usually	599	calling this function, or cope with the fact afterwards (which is usually
588	the easiest thing, you can just ignore the watchers and/or C<free ()> them	600	the easiest thing, you can just ignore the watchers and/or C<free ()> them
…		…
590		602
591	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
592	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
593	as signal and child watchers) would need to be stopped manually.	605	as signal and child watchers) would need to be stopped manually.
594		606
595	In general it is not advisable to call this function except in the	607	This function is normally used on loop objects allocated by
596	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.
597	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>
598	C<ev_loop_new> and C<ev_loop_destroy>.	614	and C<ev_loop_destroy>.
599		615
600	=item ev_loop_destroy (loop)	616	=item ev_loop_fork (loop)
601		617
602	Like C<ev_default_destroy>, but destroys an event loop created by an
603	earlier call to C<ev_loop_new>.
604
605	=item ev_default_fork ()
606
607	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
608	to reinitialise the kernel state for backends that have one. Despite the	619	reinitialise the kernel state for backends that have one. Despite the
609	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
610	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
611	sense). You I<must> call it in the child before using any of the libev	622	child before resuming or calling C<ev_run>.
612	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.
613		628
614	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
615	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
616	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).
617		635
618	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
619	it just in case after a fork. To make this easy, the function will fit in	637	it just in case after a fork.
620	quite nicely into a call to C<pthread_atfork>:
621		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	...
622	pthread_atfork (0, 0, ev_default_fork);	649	pthread_atfork (0, 0, post_fork_child);
623
624	=item ev_loop_fork (loop)
625
626	Like C<ev_default_fork>, but acts on an event loop created by
627	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
628	after fork that you want to re-use in the child, and how you do this is
629	entirely your own problem.
630		650
631	=item int ev_is_default_loop (loop)	651	=item int ev_is_default_loop (loop)
632		652
633	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
634	otherwise.	654	otherwise.
635		655
636	=item unsigned int ev_loop_count (loop)	656	=item unsigned int ev_iteration (loop)
637		657
638	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
639	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>
640	happily wraps around with enough iterations.	660	and happily wraps around with enough iterations.
641		661
642	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
643	"ticks" the number of loop iterations), as it roughly corresponds with	663	"ticks" the number of loop iterations), as it roughly corresponds with
644	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.
645		666
646	=item unsigned int ev_loop_depth (loop)	667	=item unsigned int ev_depth (loop)
647		668
648	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
649	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.
650		671
651	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
652	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),
653	in which case it is higher.	674	in which case it is higher.
654		675
655	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	676	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
656	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.
657		679
658	=item unsigned int ev_backend (loop)	680	=item unsigned int ev_backend (loop)
659		681
660	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
661	use.	683	use.
…		…
670		692
671	=item ev_now_update (loop)	693	=item ev_now_update (loop)
672		694
673	Establishes the current time by querying the kernel, updating the time	695	Establishes the current time by querying the kernel, updating the time
674	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
675	is usually done automatically within C<ev_loop ()>.	697	is usually done automatically within C<ev_run ()>.
676		698
677	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
678	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
679	the current time is a good idea.	701	the current time is a good idea.
680		702
…		…
682		704
683	=item ev_suspend (loop)	705	=item ev_suspend (loop)
684		706
685	=item ev_resume (loop)	707	=item ev_resume (loop)
686		708
687	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
688	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.
689		711
690	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
691	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
692	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
693	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>
…		…
695	C<ev_resume> directly afterwards to resume timer processing.	717	C<ev_resume> directly afterwards to resume timer processing.
696		718
697	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
698	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
699	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
700	occured while suspended).	722	occurred while suspended).
701		723
702	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
703	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>
704	without a previous call to C<ev_suspend>.	726	without a previous call to C<ev_suspend>.
705		727
706	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
707	event loop time (see C<ev_now_update>).	729	event loop time (see C<ev_now_update>).
708		730
709	=item ev_loop (loop, int flags)	731	=item ev_run (loop, int flags)
710		732
711	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
712	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
713	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>.
714		738
715	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
716	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.
717		742
718	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
719	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
720	finished (especially in interactive programs), but having a program	745	finished (especially in interactive programs), but having a program
721	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
722	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
723	beauty.	748	beauty.
724		749
725	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
726	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
727	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
728	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.
729		755
730	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
731	necessary) and will handle those and any already outstanding ones. It	757	necessary) and will handle those and any already outstanding ones. It
732	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
733	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
734	user-registered callback will be called), and will return after one	760	user-registered callback will be called), and will return after one
735	iteration of the loop.	761	iteration of the loop.
736		762
737	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
738	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
739	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
740	usually a better approach for this kind of thing.	766	usually a better approach for this kind of thing.
741		767
742	Here are the gory details of what C<ev_loop> does:	768	Here are the gory details of what C<ev_run> does:
743		769
		770	- Increment loop depth.
		771	- Reset the ev_break status.
744	- Before the first iteration, call any pending watchers.	772	- Before the first iteration, call any pending watchers.
		773	LOOP:
745	* If EVFLAG_FORKCHECK was used, check for a fork.	774	- If EVFLAG_FORKCHECK was used, check for a fork.
746	- 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.
747	- Queue and call all prepare watchers.	776	- Queue and call all prepare watchers.
		777	- If ev_break was called, goto FINISH.
748	- If we have been forked, detach and recreate the kernel state	778	- If we have been forked, detach and recreate the kernel state
749	as to not disturb the other process.	779	as to not disturb the other process.
750	- Update the kernel state with all outstanding changes.	780	- Update the kernel state with all outstanding changes.
751	- Update the "event loop time" (ev_now ()).	781	- Update the "event loop time" (ev_now ()).
752	- Calculate for how long to sleep or block, if at all	782	- Calculate for how long to sleep or block, if at all
753	(active idle watchers, EVLOOP_NONBLOCK or not having	783	(active idle watchers, EVRUN_NOWAIT or not having
754	any active watchers at all will result in not sleeping).	784	any active watchers at all will result in not sleeping).
755	- 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.
756	- Block the process, waiting for any events.	787	- Block the process, waiting for any events.
757	- Queue all outstanding I/O (fd) events.	788	- Queue all outstanding I/O (fd) events.
758	- 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.
759	- Queue all expired timers.	790	- Queue all expired timers.
760	- Queue all expired periodics.	791	- Queue all expired periodics.
761	- Unless any events are pending now, queue all idle watchers.	792	- Queue all idle watchers with priority higher than that of pending events.
762	- Queue all check watchers.	793	- Queue all check watchers.
763	- 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).
764	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
765	be handled here by queueing them when their watcher gets executed.	796	be handled here by queueing them when their watcher gets executed.
766	- 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
767	were used, or there are no active watchers, return, otherwise	798	were used, or there are no active watchers, goto FINISH, otherwise
768	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.
769		804
770	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
771	anymore.	806	anymore.
772		807
773	... queue jobs here, make sure they register event watchers as long	808	... queue jobs here, make sure they register event watchers as long
774	... 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..)
775	ev_loop (my_loop, 0);	810	ev_run (my_loop, 0);
776	... jobs done or somebody called unloop. yeah!	811	... jobs done or somebody called unloop. yeah!
777		812
778	=item ev_unloop (loop, how)	813	=item ev_break (loop, how)
779		814
780	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
781	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
782	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
783	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.
784		819
785	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.
786		821
787	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##
788		823
789	=item ev_ref (loop)	824	=item ev_ref (loop)
790		825
791	=item ev_unref (loop)	826	=item ev_unref (loop)
792		827
793	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
794	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
795	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.
796		831
797	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
798	unregister, but that nevertheless should not keep C<ev_loop> from	833	unregister, but that nevertheless should not keep C<ev_run> from
799	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>
800	before stopping it.	835	before stopping it.
801		836
802	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
803	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
804	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
805	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
806	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
807	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
808	before, respectively. Note also that libev might stop watchers itself	843	before, respectively. Note also that libev might stop watchers itself
809	(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>
810	in the callback).	845	in the callback).
811		846
812	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>
813	running when nothing else is active.	848	running when nothing else is active.
814		849
815	ev_signal exitsig;	850	ev_signal exitsig;
816	ev_signal_init (&exitsig, sig_cb, SIGINT);	851	ev_signal_init (&exitsig, sig_cb, SIGINT);
817	ev_signal_start (loop, &exitsig);	852	ev_signal_start (loop, &exitsig);
…		…
862	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>,
863	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
864	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
865	parallelity, then this setting will limit your transaction rate (if you	900	parallelity, then this setting will limit your transaction rate (if you
866	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,
867	then you can't do more than 100 transations per second).	902	then you can't do more than 100 transactions per second).
868		903
869	Setting the I<timeout collect interval> can improve the opportunity for	904	Setting the I<timeout collect interval> can improve the opportunity for
870	saving power, as the program will "bundle" timer callback invocations that	905	saving power, as the program will "bundle" timer callback invocations that
871	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
872	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
…		…
880	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	915	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
881		916
882	=item ev_invoke_pending (loop)	917	=item ev_invoke_pending (loop)
883		918
884	This call will simply invoke all pending watchers while resetting their	919	This call will simply invoke all pending watchers while resetting their
885	pending state. Normally, C<ev_loop> does this automatically when required,	920	pending state. Normally, C<ev_run> does this automatically when required,
886	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).
887		926
888	=item int ev_pending_count (loop)	927	=item int ev_pending_count (loop)
889		928
890	Returns the number of pending watchers - zero indicates that no watchers	929	Returns the number of pending watchers - zero indicates that no watchers
891	are pending.	930	are pending.
892		931
893	=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))
894		933
895	This overrides the invoke pending functionality of the loop: Instead of	934	This overrides the invoke pending functionality of the loop: Instead of
896	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
897	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
898	invoke the actual watchers inside another context (another thread etc.).	937	invoke the actual watchers inside another context (another thread etc.).
899		938
900	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
901	callback.	940	callback.
…		…
904		943
905	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
906	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
907	each call to a libev function.	946	each call to a libev function.
908		947
909	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
910	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
911	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
912	and I<acquire> callbacks on the loop.	951	I<release> and I<acquire> callbacks on the loop.
913		952
914	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
915	suspended waiting for new events, and C<acquire> is called just	954	suspended waiting for new events, and C<acquire> is called just
916	afterwards.	955	afterwards.
917		956
…		…
920		959
921	While event loop modifications are allowed between invocations of	960	While event loop modifications are allowed between invocations of
922	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
923	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
924	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
925	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
926	to take note of any changes you made.	965	to take note of any changes you made.
927		966
928	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
929	invocations of C<release> and C<acquire>.	968	invocations of C<release> and C<acquire>.
930		969
931	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
932	document.	971	document.
933		972
…		…
942	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,
943	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
944	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
945	any other purpose as well.	984	any other purpose as well.
946		985
947	=item ev_loop_verify (loop)	986	=item ev_verify (loop)
948		987
949	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
950	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
951	through all internal structures and checks them for validity. If anything	990	through all internal structures and checks them for validity. If anything
952	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
…		…
963		1002
964	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
965	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
966	watchers and C<ev_io_start> for I/O watchers.	1005	watchers and C<ev_io_start> for I/O watchers.
967		1006
968	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
969	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
970	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:
971		1011
972	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)
973	{	1013	{
974	ev_io_stop (w);	1014	ev_io_stop (w);
975	ev_unloop (loop, EVUNLOOP_ALL);	1015	ev_break (loop, EVBREAK_ALL);
976	}	1016	}
977		1017
978	struct ev_loop *loop = ev_default_loop (0);	1018	struct ev_loop *loop = ev_default_loop (0);
979		1019
980	ev_io stdin_watcher;	1020	ev_io stdin_watcher;
981		1021
982	ev_init (&stdin_watcher, my_cb);	1022	ev_init (&stdin_watcher, my_cb);
983	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1023	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
984	ev_io_start (loop, &stdin_watcher);	1024	ev_io_start (loop, &stdin_watcher);
985		1025
986	ev_loop (loop, 0);	1026	ev_run (loop, 0);
987		1027
988	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
989	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
990	stack).	1030	stack).
991		1031
992	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>
993	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).
994		1034
995	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
996	(watcher *, callback)>, which expects a callback to be provided. This	1036	*, callback)>, which expects a callback to be provided. This callback is
997	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
998	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
999	is readable and/or writable).	1039	and/or writable).
1000		1040
1001	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 *, ...) >>
1002	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
1003	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<<
1004	ev_TYPE_init (watcher *, callback, ...) >>.	1044	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1027	=item C<EV_WRITE>	1067	=item C<EV_WRITE>
1028		1068
1029	The file descriptor in the C<ev_io> watcher has become readable and/or	1069	The file descriptor in the C<ev_io> watcher has become readable and/or
1030	writable.	1070	writable.
1031		1071
1032	=item C<EV_TIMEOUT>	1072	=item C<EV_TIMER>
1033		1073
1034	The C<ev_timer> watcher has timed out.	1074	The C<ev_timer> watcher has timed out.
1035		1075
1036	=item C<EV_PERIODIC>	1076	=item C<EV_PERIODIC>
1037		1077
…		…
1055		1095
1056	=item C<EV_PREPARE>	1096	=item C<EV_PREPARE>
1057		1097
1058	=item C<EV_CHECK>	1098	=item C<EV_CHECK>
1059		1099
1060	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
1061	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
1062	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
1063	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
1064	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
1065	(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
1066	C<ev_loop> from blocking).	1106	C<ev_run> from blocking).
1067		1107
1068	=item C<EV_EMBED>	1108	=item C<EV_EMBED>
1069		1109
1070	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.
1071		1111
…		…
1099	example it might indicate that a fd is readable or writable, and if your	1139	example it might indicate that a fd is readable or writable, and if your
1100	callbacks is well-written it can just attempt the operation and cope with	1140	callbacks is well-written it can just attempt the operation and cope with
1101	the error from read() or write(). This will not work in multi-threaded	1141	the error from read() or write(). This will not work in multi-threaded
1102	programs, though, as the fd could already be closed and reused for another	1142	programs, though, as the fd could already be closed and reused for another
1103	thing, so beware.	1143	thing, so beware.
		1144
		1145	=back
		1146
		1147	=head2 WATCHER STATES
		1148
		1149	There are various watcher states mentioned throughout this manual -
		1150	active, pending and so on. In this section these states and the rules to
		1151	transition between them will be described in more detail - and while these
		1152	rules might look complicated, they usually do "the right thing".
		1153
		1154	=over 4
		1155
		1156	=item initialiased
		1157
		1158	Before a watcher can be registered with the event looop it has to be
		1159	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1160	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1161
		1162	In this state it is simply some block of memory that is suitable for use
		1163	in an event loop. It can be moved around, freed, reused etc. at will.
		1164
		1165	=item started/running/active
		1166
		1167	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1168	property of the event loop, and is actively waiting for events. While in
		1169	this state it cannot be accessed (except in a few documented ways), moved,
		1170	freed or anything else - the only legal thing is to keep a pointer to it,
		1171	and call libev functions on it that are documented to work on active watchers.
		1172
		1173	=item pending
		1174
		1175	If a watcher is active and libev determines that an event it is interested
		1176	in has occurred (such as a timer expiring), it will become pending. It will
		1177	stay in this pending state until either it is stopped or its callback is
		1178	about to be invoked, so it is not normally pending inside the watcher
		1179	callback.
		1180
		1181	The watcher might or might not be active while it is pending (for example,
		1182	an expired non-repeating timer can be pending but no longer active). If it
		1183	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1184	but it is still property of the event loop at this time, so cannot be
		1185	moved, freed or reused. And if it is active the rules described in the
		1186	previous item still apply.
		1187
		1188	It is also possible to feed an event on a watcher that is not active (e.g.
		1189	via C<ev_feed_event>), in which case it becomes pending without being
		1190	active.
		1191
		1192	=item stopped
		1193
		1194	A watcher can be stopped implicitly by libev (in which case it might still
		1195	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1196	latter will clear any pending state the watcher might be in, regardless
		1197	of whether it was active or not, so stopping a watcher explicitly before
		1198	freeing it is often a good idea.
		1199
		1200	While stopped (and not pending) the watcher is essentially in the
		1201	initialised state, that is it can be reused, moved, modified in any way
		1202	you wish.
1104		1203
1105	=back	1204	=back
1106		1205
1107	=head2 GENERIC WATCHER FUNCTIONS	1206	=head2 GENERIC WATCHER FUNCTIONS
1108		1207
…		…
1370		1469
1371	For example, to emulate how many other event libraries handle priorities,	1470	For example, to emulate how many other event libraries handle priorities,
1372	you can associate an C<ev_idle> watcher to each such watcher, and in	1471	you can associate an C<ev_idle> watcher to each such watcher, and in
1373	the normal watcher callback, you just start the idle watcher. The real	1472	the normal watcher callback, you just start the idle watcher. The real
1374	processing is done in the idle watcher callback. This causes libev to	1473	processing is done in the idle watcher callback. This causes libev to
1375	continously poll and process kernel event data for the watcher, but when	1474	continuously poll and process kernel event data for the watcher, but when
1376	the lock-out case is known to be rare (which in turn is rare :), this is	1475	the lock-out case is known to be rare (which in turn is rare :), this is
1377	workable.	1476	workable.
1378		1477
1379	Usually, however, the lock-out model implemented that way will perform	1478	Usually, however, the lock-out model implemented that way will perform
1380	miserably under the type of load it was designed to handle. In that case,	1479	miserably under the type of load it was designed to handle. In that case,
…		…
1394	{	1493	{
1395	// stop the I/O watcher, we received the event, but	1494	// stop the I/O watcher, we received the event, but
1396	// are not yet ready to handle it.	1495	// are not yet ready to handle it.
1397	ev_io_stop (EV_A_ w);	1496	ev_io_stop (EV_A_ w);
1398		1497
1399	// start the idle watcher to ahndle the actual event.	1498	// start the idle watcher to handle the actual event.
1400	// it will not be executed as long as other watchers	1499	// it will not be executed as long as other watchers
1401	// with the default priority are receiving events.	1500	// with the default priority are receiving events.
1402	ev_idle_start (EV_A_ &idle);	1501	ev_idle_start (EV_A_ &idle);
1403	}	1502	}
1404		1503
…		…
1458		1557
1459	If you cannot use non-blocking mode, then force the use of a	1558	If you cannot use non-blocking mode, then force the use of a
1460	known-to-be-good backend (at the time of this writing, this includes only	1559	known-to-be-good backend (at the time of this writing, this includes only
1461	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1560	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1462	descriptors for which non-blocking operation makes no sense (such as	1561	descriptors for which non-blocking operation makes no sense (such as
1463	files) - libev doesn't guarentee any specific behaviour in that case.	1562	files) - libev doesn't guarantee any specific behaviour in that case.
1464		1563
1465	Another thing you have to watch out for is that it is quite easy to	1564	Another thing you have to watch out for is that it is quite easy to
1466	receive "spurious" readiness notifications, that is your callback might	1565	receive "spurious" readiness notifications, that is your callback might
1467	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1566	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1468	because there is no data. Not only are some backends known to create a	1567	because there is no data. Not only are some backends known to create a
…		…
1533		1632
1534	So when you encounter spurious, unexplained daemon exits, make sure you	1633	So when you encounter spurious, unexplained daemon exits, make sure you
1535	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1634	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1536	somewhere, as that would have given you a big clue).	1635	somewhere, as that would have given you a big clue).
1537		1636
		1637	=head3 The special problem of accept()ing when you can't
		1638
		1639	Many implementations of the POSIX C<accept> function (for example,
		1640	found in post-2004 Linux) have the peculiar behaviour of not removing a
		1641	connection from the pending queue in all error cases.
		1642
		1643	For example, larger servers often run out of file descriptors (because
		1644	of resource limits), causing C<accept> to fail with C<ENFILE> but not
		1645	rejecting the connection, leading to libev signalling readiness on
		1646	the next iteration again (the connection still exists after all), and
		1647	typically causing the program to loop at 100% CPU usage.
		1648
		1649	Unfortunately, the set of errors that cause this issue differs between
		1650	operating systems, there is usually little the app can do to remedy the
		1651	situation, and no known thread-safe method of removing the connection to
		1652	cope with overload is known (to me).
		1653
		1654	One of the easiest ways to handle this situation is to just ignore it
		1655	- when the program encounters an overload, it will just loop until the
		1656	situation is over. While this is a form of busy waiting, no OS offers an
		1657	event-based way to handle this situation, so it's the best one can do.
		1658
		1659	A better way to handle the situation is to log any errors other than
		1660	C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
		1661	messages, and continue as usual, which at least gives the user an idea of
		1662	what could be wrong ("raise the ulimit!"). For extra points one could stop
		1663	the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
		1664	usage.
		1665
		1666	If your program is single-threaded, then you could also keep a dummy file
		1667	descriptor for overload situations (e.g. by opening F</dev/null>), and
		1668	when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
		1669	close that fd, and create a new dummy fd. This will gracefully refuse
		1670	clients under typical overload conditions.
		1671
		1672	The last way to handle it is to simply log the error and C<exit>, as
		1673	is often done with C<malloc> failures, but this results in an easy
		1674	opportunity for a DoS attack.
1538		1675
1539	=head3 Watcher-Specific Functions	1676	=head3 Watcher-Specific Functions
1540		1677
1541	=over 4	1678	=over 4
1542		1679
…		…
1574	...	1711	...
1575	struct ev_loop *loop = ev_default_init (0);	1712	struct ev_loop *loop = ev_default_init (0);
1576	ev_io stdin_readable;	1713	ev_io stdin_readable;
1577	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1714	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1578	ev_io_start (loop, &stdin_readable);	1715	ev_io_start (loop, &stdin_readable);
1579	ev_loop (loop, 0);	1716	ev_run (loop, 0);
1580		1717
1581		1718
1582	=head2 C<ev_timer> - relative and optionally repeating timeouts	1719	=head2 C<ev_timer> - relative and optionally repeating timeouts
1583		1720
1584	Timer watchers are simple relative timers that generate an event after a	1721	Timer watchers are simple relative timers that generate an event after a
…		…
1593	The callback is guaranteed to be invoked only I<after> its timeout has	1730	The callback is guaranteed to be invoked only I<after> its timeout has
1594	passed (not I<at>, so on systems with very low-resolution clocks this	1731	passed (not I<at>, so on systems with very low-resolution clocks this
1595	might introduce a small delay). If multiple timers become ready during the	1732	might introduce a small delay). If multiple timers become ready during the
1596	same loop iteration then the ones with earlier time-out values are invoked	1733	same loop iteration then the ones with earlier time-out values are invoked
1597	before ones of the same priority with later time-out values (but this is	1734	before ones of the same priority with later time-out values (but this is
1598	no longer true when a callback calls C<ev_loop> recursively).	1735	no longer true when a callback calls C<ev_run> recursively).
1599		1736
1600	=head3 Be smart about timeouts	1737	=head3 Be smart about timeouts
1601		1738
1602	Many real-world problems involve some kind of timeout, usually for error	1739	Many real-world problems involve some kind of timeout, usually for error
1603	recovery. A typical example is an HTTP request - if the other side hangs,	1740	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1689	ev_tstamp timeout = last_activity + 60.;	1826	ev_tstamp timeout = last_activity + 60.;
1690		1827
1691	// if last_activity + 60. is older than now, we did time out	1828	// if last_activity + 60. is older than now, we did time out
1692	if (timeout < now)	1829	if (timeout < now)
1693	{	1830	{
1694	// timeout occured, take action	1831	// timeout occurred, take action
1695	}	1832	}
1696	else	1833	else
1697	{	1834	{
1698	// callback was invoked, but there was some activity, re-arm	1835	// callback was invoked, but there was some activity, re-arm
1699	// the watcher to fire in last_activity + 60, which is	1836	// the watcher to fire in last_activity + 60, which is
…		…
1721	to the current time (meaning we just have some activity :), then call the	1858	to the current time (meaning we just have some activity :), then call the
1722	callback, which will "do the right thing" and start the timer:	1859	callback, which will "do the right thing" and start the timer:
1723		1860
1724	ev_init (timer, callback);	1861	ev_init (timer, callback);
1725	last_activity = ev_now (loop);	1862	last_activity = ev_now (loop);
1726	callback (loop, timer, EV_TIMEOUT);	1863	callback (loop, timer, EV_TIMER);
1727		1864
1728	And when there is some activity, simply store the current time in	1865	And when there is some activity, simply store the current time in
1729	C<last_activity>, no libev calls at all:	1866	C<last_activity>, no libev calls at all:
1730		1867
1731	last_actiivty = ev_now (loop);	1868	last_activity = ev_now (loop);
1732		1869
1733	This technique is slightly more complex, but in most cases where the	1870	This technique is slightly more complex, but in most cases where the
1734	time-out is unlikely to be triggered, much more efficient.	1871	time-out is unlikely to be triggered, much more efficient.
1735		1872
1736	Changing the timeout is trivial as well (if it isn't hard-coded in the	1873	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1774		1911
1775	=head3 The special problem of time updates	1912	=head3 The special problem of time updates
1776		1913
1777	Establishing the current time is a costly operation (it usually takes at	1914	Establishing the current time is a costly operation (it usually takes at
1778	least two system calls): EV therefore updates its idea of the current	1915	least two system calls): EV therefore updates its idea of the current
1779	time only before and after C<ev_loop> collects new events, which causes a	1916	time only before and after C<ev_run> collects new events, which causes a
1780	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1917	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1781	lots of events in one iteration.	1918	lots of events in one iteration.
1782		1919
1783	The relative timeouts are calculated relative to the C<ev_now ()>	1920	The relative timeouts are calculated relative to the C<ev_now ()>
1784	time. This is usually the right thing as this timestamp refers to the time	1921	time. This is usually the right thing as this timestamp refers to the time
…		…
1862	Returns the remaining time until a timer fires. If the timer is active,	1999	Returns the remaining time until a timer fires. If the timer is active,
1863	then this time is relative to the current event loop time, otherwise it's	2000	then this time is relative to the current event loop time, otherwise it's
1864	the timeout value currently configured.	2001	the timeout value currently configured.
1865		2002
1866	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns	2003	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
1867	C<5>. When the timer is started and one second passes, C<ev_timer_remain>	2004	C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
1868	will return C<4>. When the timer expires and is restarted, it will return	2005	will return C<4>. When the timer expires and is restarted, it will return
1869	roughly C<7> (likely slightly less as callback invocation takes some time,	2006	roughly C<7> (likely slightly less as callback invocation takes some time,
1870	too), and so on.	2007	too), and so on.
1871		2008
1872	=item ev_tstamp repeat [read-write]	2009	=item ev_tstamp repeat [read-write]
…		…
1901	}	2038	}
1902		2039
1903	ev_timer mytimer;	2040	ev_timer mytimer;
1904	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2041	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1905	ev_timer_again (&mytimer); /* start timer */	2042	ev_timer_again (&mytimer); /* start timer */
1906	ev_loop (loop, 0);	2043	ev_run (loop, 0);
1907		2044
1908	// and in some piece of code that gets executed on any "activity":	2045	// and in some piece of code that gets executed on any "activity":
1909	// reset the timeout to start ticking again at 10 seconds	2046	// reset the timeout to start ticking again at 10 seconds
1910	ev_timer_again (&mytimer);	2047	ev_timer_again (&mytimer);
1911		2048
…		…
1937		2074
1938	As with timers, the callback is guaranteed to be invoked only when the	2075	As with timers, the callback is guaranteed to be invoked only when the
1939	point in time where it is supposed to trigger has passed. If multiple	2076	point in time where it is supposed to trigger has passed. If multiple
1940	timers become ready during the same loop iteration then the ones with	2077	timers become ready during the same loop iteration then the ones with
1941	earlier time-out values are invoked before ones with later time-out values	2078	earlier time-out values are invoked before ones with later time-out values
1942	(but this is no longer true when a callback calls C<ev_loop> recursively).	2079	(but this is no longer true when a callback calls C<ev_run> recursively).
1943		2080
1944	=head3 Watcher-Specific Functions and Data Members	2081	=head3 Watcher-Specific Functions and Data Members
1945		2082
1946	=over 4	2083	=over 4
1947		2084
…		…
2075	Example: Call a callback every hour, or, more precisely, whenever the	2212	Example: Call a callback every hour, or, more precisely, whenever the
2076	system time is divisible by 3600. The callback invocation times have	2213	system time is divisible by 3600. The callback invocation times have
2077	potentially a lot of jitter, but good long-term stability.	2214	potentially a lot of jitter, but good long-term stability.
2078		2215
2079	static void	2216	static void
2080	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2217	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
2081	{	2218	{
2082	... its now a full hour (UTC, or TAI or whatever your clock follows)	2219	... its now a full hour (UTC, or TAI or whatever your clock follows)
2083	}	2220	}
2084		2221
2085	ev_periodic hourly_tick;	2222	ev_periodic hourly_tick;
…		…
2132	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should	2269	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
2133	not be unduly interrupted. If you have a problem with system calls getting	2270	not be unduly interrupted. If you have a problem with system calls getting
2134	interrupted by signals you can block all signals in an C<ev_check> watcher	2271	interrupted by signals you can block all signals in an C<ev_check> watcher
2135	and unblock them in an C<ev_prepare> watcher.	2272	and unblock them in an C<ev_prepare> watcher.
2136		2273
2137	=head3 The special problem of inheritance over execve	2274	=head3 The special problem of inheritance over fork/execve/pthread_create
2138		2275
2139	Both the signal mask (C<sigprocmask>) and the signal disposition	2276	Both the signal mask (C<sigprocmask>) and the signal disposition
2140	(C<sigaction>) are unspecified after starting a signal watcher (and after	2277	(C<sigaction>) are unspecified after starting a signal watcher (and after
2141	stopping it again), that is, libev might or might not block the signal,	2278	stopping it again), that is, libev might or might not block the signal,
2142	and might or might not set or restore the installed signal handler.	2279	and might or might not set or restore the installed signal handler.
…		…
2152		2289
2153	The simplest way to ensure that the signal mask is reset in the child is	2290	The simplest way to ensure that the signal mask is reset in the child is
2154	to install a fork handler with C<pthread_atfork> that resets it. That will	2291	to install a fork handler with C<pthread_atfork> that resets it. That will
2155	catch fork calls done by libraries (such as the libc) as well.	2292	catch fork calls done by libraries (such as the libc) as well.
2156		2293
2157	In current versions of libev, you can also ensure that the signal mask is	2294	In current versions of libev, the signal will not be blocked indefinitely
2158	not blocking any signals (except temporarily, so thread users watch out)	2295	unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
2159	by specifying the C<EVFLAG_NOSIGFD> when creating the event loop. This	2296	the window of opportunity for problems, it will not go away, as libev
2160	is not guaranteed for future versions, however.	2297	I<has> to modify the signal mask, at least temporarily.
		2298
		2299	So I can't stress this enough: I<If you do not reset your signal mask when
		2300	you expect it to be empty, you have a race condition in your code>. This
		2301	is not a libev-specific thing, this is true for most event libraries.
2161		2302
2162	=head3 Watcher-Specific Functions and Data Members	2303	=head3 Watcher-Specific Functions and Data Members
2163		2304
2164	=over 4	2305	=over 4
2165		2306
…		…
2181	Example: Try to exit cleanly on SIGINT.	2322	Example: Try to exit cleanly on SIGINT.
2182		2323
2183	static void	2324	static void
2184	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2325	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2185	{	2326	{
2186	ev_unloop (loop, EVUNLOOP_ALL);	2327	ev_break (loop, EVBREAK_ALL);
2187	}	2328	}
2188		2329
2189	ev_signal signal_watcher;	2330	ev_signal signal_watcher;
2190	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2331	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2191	ev_signal_start (loop, &signal_watcher);	2332	ev_signal_start (loop, &signal_watcher);
…		…
2577		2718
2578	Prepare and check watchers are usually (but not always) used in pairs:	2719	Prepare and check watchers are usually (but not always) used in pairs:
2579	prepare watchers get invoked before the process blocks and check watchers	2720	prepare watchers get invoked before the process blocks and check watchers
2580	afterwards.	2721	afterwards.
2581		2722
2582	You I<must not> call C<ev_loop> or similar functions that enter	2723	You I<must not> call C<ev_run> or similar functions that enter
2583	the current event loop from either C<ev_prepare> or C<ev_check>	2724	the current event loop from either C<ev_prepare> or C<ev_check>
2584	watchers. Other loops than the current one are fine, however. The	2725	watchers. Other loops than the current one are fine, however. The
2585	rationale behind this is that you do not need to check for recursion in	2726	rationale behind this is that you do not need to check for recursion in
2586	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2727	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2587	C<ev_check> so if you have one watcher of each kind they will always be	2728	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2755		2896
2756	if (timeout >= 0)	2897	if (timeout >= 0)
2757	// create/start timer	2898	// create/start timer
2758		2899
2759	// poll	2900	// poll
2760	ev_loop (EV_A_ 0);	2901	ev_run (EV_A_ 0);
2761		2902
2762	// stop timer again	2903	// stop timer again
2763	if (timeout >= 0)	2904	if (timeout >= 0)
2764	ev_timer_stop (EV_A_ &to);	2905	ev_timer_stop (EV_A_ &to);
2765		2906
…		…
2843	if you do not want that, you need to temporarily stop the embed watcher).	2984	if you do not want that, you need to temporarily stop the embed watcher).
2844		2985
2845	=item ev_embed_sweep (loop, ev_embed *)	2986	=item ev_embed_sweep (loop, ev_embed *)
2846		2987
2847	Make a single, non-blocking sweep over the embedded loop. This works	2988	Make a single, non-blocking sweep over the embedded loop. This works
2848	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2989	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2849	appropriate way for embedded loops.	2990	appropriate way for embedded loops.
2850		2991
2851	=item struct ev_loop *other [read-only]	2992	=item struct ev_loop *other [read-only]
2852		2993
2853	The embedded event loop.	2994	The embedded event loop.
…		…
2913	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3054	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2914	handlers will be invoked, too, of course.	3055	handlers will be invoked, too, of course.
2915		3056
2916	=head3 The special problem of life after fork - how is it possible?	3057	=head3 The special problem of life after fork - how is it possible?
2917		3058
2918	Most uses of C<fork()> consist of forking, then some simple calls to ste	3059	Most uses of C<fork()> consist of forking, then some simple calls to set
2919	up/change the process environment, followed by a call to C<exec()>. This	3060	up/change the process environment, followed by a call to C<exec()>. This
2920	sequence should be handled by libev without any problems.	3061	sequence should be handled by libev without any problems.
2921		3062
2922	This changes when the application actually wants to do event handling	3063	This changes when the application actually wants to do event handling
2923	in the child, or both parent in child, in effect "continuing" after the	3064	in the child, or both parent in child, in effect "continuing" after the
…		…
2939	disadvantage of having to use multiple event loops (which do not support	3080	disadvantage of having to use multiple event loops (which do not support
2940	signal watchers).	3081	signal watchers).
2941		3082
2942	When this is not possible, or you want to use the default loop for	3083	When this is not possible, or you want to use the default loop for
2943	other reasons, then in the process that wants to start "fresh", call	3084	other reasons, then in the process that wants to start "fresh", call
2944	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3085	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2945	the default loop will "orphan" (not stop) all registered watchers, so you	3086	Destroying the default loop will "orphan" (not stop) all registered
2946	have to be careful not to execute code that modifies those watchers. Note	3087	watchers, so you have to be careful not to execute code that modifies
2947	also that in that case, you have to re-register any signal watchers.	3088	those watchers. Note also that in that case, you have to re-register any
		3089	signal watchers.
2948		3090
2949	=head3 Watcher-Specific Functions and Data Members	3091	=head3 Watcher-Specific Functions and Data Members
2950		3092
2951	=over 4	3093	=over 4
2952		3094
…		…
2957	believe me.	3099	believe me.
2958		3100
2959	=back	3101	=back
2960		3102
2961		3103
2962	=head2 C<ev_async> - how to wake up another event loop	3104	=head2 C<ev_async> - how to wake up an event loop
2963		3105
2964	In general, you cannot use an C<ev_loop> from multiple threads or other	3106	In general, you cannot use an C<ev_run> from multiple threads or other
2965	asynchronous sources such as signal handlers (as opposed to multiple event	3107	asynchronous sources such as signal handlers (as opposed to multiple event
2966	loops - those are of course safe to use in different threads).	3108	loops - those are of course safe to use in different threads).
2967		3109
2968	Sometimes, however, you need to wake up another event loop you do not	3110	Sometimes, however, you need to wake up an event loop you do not control,
2969	control, for example because it belongs to another thread. This is what	3111	for example because it belongs to another thread. This is what C<ev_async>
2970	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3112	watchers do: as long as the C<ev_async> watcher is active, you can signal
2971	can signal it by calling C<ev_async_send>, which is thread- and signal	3113	it by calling C<ev_async_send>, which is thread- and signal safe.
2972	safe.
2973		3114
2974	This functionality is very similar to C<ev_signal> watchers, as signals,	3115	This functionality is very similar to C<ev_signal> watchers, as signals,
2975	too, are asynchronous in nature, and signals, too, will be compressed	3116	too, are asynchronous in nature, and signals, too, will be compressed
2976	(i.e. the number of callback invocations may be less than the number of	3117	(i.e. the number of callback invocations may be less than the number of
2977	C<ev_async_sent> calls).	3118	C<ev_async_sent> calls).
…		…
3132		3273
3133	If C<timeout> is less than 0, then no timeout watcher will be	3274	If C<timeout> is less than 0, then no timeout watcher will be
3134	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3275	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
3135	repeat = 0) will be started. C<0> is a valid timeout.	3276	repeat = 0) will be started. C<0> is a valid timeout.
3136		3277
3137	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	3278	The callback has the type C<void (*cb)(int revents, void *arg)> and is
3138	passed an C<revents> set like normal event callbacks (a combination of	3279	passed an C<revents> set like normal event callbacks (a combination of
3139	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3280	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
3140	value passed to C<ev_once>. Note that it is possible to receive I<both>	3281	value passed to C<ev_once>. Note that it is possible to receive I<both>
3141	a timeout and an io event at the same time - you probably should give io	3282	a timeout and an io event at the same time - you probably should give io
3142	events precedence.	3283	events precedence.
3143		3284
3144	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3285	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
3145		3286
3146	static void stdin_ready (int revents, void *arg)	3287	static void stdin_ready (int revents, void *arg)
3147	{	3288	{
3148	if (revents & EV_READ)	3289	if (revents & EV_READ)
3149	/* stdin might have data for us, joy! */;	3290	/* stdin might have data for us, joy! */;
3150	else if (revents & EV_TIMEOUT)	3291	else if (revents & EV_TIMER)
3151	/* doh, nothing entered */;	3292	/* doh, nothing entered */;
3152	}	3293	}
3153		3294
3154	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3295	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3155		3296
…		…
3289	myclass obj;	3430	myclass obj;
3290	ev::io iow;	3431	ev::io iow;
3291	iow.set <myclass, &myclass::io_cb> (&obj);	3432	iow.set <myclass, &myclass::io_cb> (&obj);
3292		3433
3293	=item w->set (object *)	3434	=item w->set (object *)
3294
3295	This is an B<experimental> feature that might go away in a future version.
3296		3435
3297	This is a variation of a method callback - leaving out the method to call	3436	This is a variation of a method callback - leaving out the method to call
3298	will default the method to C<operator ()>, which makes it possible to use	3437	will default the method to C<operator ()>, which makes it possible to use
3299	functor objects without having to manually specify the C<operator ()> all	3438	functor objects without having to manually specify the C<operator ()> all
3300	the time. Incidentally, you can then also leave out the template argument	3439	the time. Incidentally, you can then also leave out the template argument
…		…
3340	Associates a different C<struct ev_loop> with this watcher. You can only	3479	Associates a different C<struct ev_loop> with this watcher. You can only
3341	do this when the watcher is inactive (and not pending either).	3480	do this when the watcher is inactive (and not pending either).
3342		3481
3343	=item w->set ([arguments])	3482	=item w->set ([arguments])
3344		3483
3345	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3484	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3346	called at least once. Unlike the C counterpart, an active watcher gets	3485	method or a suitable start method must be called at least once. Unlike the
3347	automatically stopped and restarted when reconfiguring it with this	3486	C counterpart, an active watcher gets automatically stopped and restarted
3348	method.	3487	when reconfiguring it with this method.
3349		3488
3350	=item w->start ()	3489	=item w->start ()
3351		3490
3352	Starts the watcher. Note that there is no C<loop> argument, as the	3491	Starts the watcher. Note that there is no C<loop> argument, as the
3353	constructor already stores the event loop.	3492	constructor already stores the event loop.
3354		3493
		3494	=item w->start ([arguments])
		3495
		3496	Instead of calling C<set> and C<start> methods separately, it is often
		3497	convenient to wrap them in one call. Uses the same type of arguments as
		3498	the configure C<set> method of the watcher.
		3499
3355	=item w->stop ()	3500	=item w->stop ()
3356		3501
3357	Stops the watcher if it is active. Again, no C<loop> argument.	3502	Stops the watcher if it is active. Again, no C<loop> argument.
3358		3503
3359	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3504	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3371		3516
3372	=back	3517	=back
3373		3518
3374	=back	3519	=back
3375		3520
3376	Example: Define a class with an IO and idle watcher, start one of them in	3521	Example: Define a class with two I/O and idle watchers, start the I/O
3377	the constructor.	3522	watchers in the constructor.
3378		3523
3379	class myclass	3524	class myclass
3380	{	3525	{
3381	ev::io io ; void io_cb (ev::io &w, int revents);	3526	ev::io io ; void io_cb (ev::io &w, int revents);
		3527	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3382	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3528	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3383		3529
3384	myclass (int fd)	3530	myclass (int fd)
3385	{	3531	{
3386	io .set <myclass, &myclass::io_cb > (this);	3532	io .set <myclass, &myclass::io_cb > (this);
		3533	io2 .set <myclass, &myclass::io2_cb > (this);
3387	idle.set <myclass, &myclass::idle_cb> (this);	3534	idle.set <myclass, &myclass::idle_cb> (this);
3388		3535
3389	io.start (fd, ev::READ);	3536	io.set (fd, ev::WRITE); // configure the watcher
		3537	io.start (); // start it whenever convenient
		3538
		3539	io2.start (fd, ev::READ); // set + start in one call
3390	}	3540	}
3391	};	3541	};
3392		3542
3393		3543
3394	=head1 OTHER LANGUAGE BINDINGS	3544	=head1 OTHER LANGUAGE BINDINGS
…		…
3442	Erkki Seppala has written Ocaml bindings for libev, to be found at	3592	Erkki Seppala has written Ocaml bindings for libev, to be found at
3443	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.	3593	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
3444		3594
3445	=item Lua	3595	=item Lua
3446		3596
3447	Brian Maher has written a partial interface to libev	3597	Brian Maher has written a partial interface to libev for lua (at the
3448	for lua (only C<ev_io> and C<ev_timer>), to be found at	3598	time of this writing, only C<ev_io> and C<ev_timer>), to be found at
3449	L<http://github.com/brimworks/lua-ev>.	3599	L<http://github.com/brimworks/lua-ev>.
3450		3600
3451	=back	3601	=back
3452		3602
3453		3603
…		…
3468	loop argument"). The C<EV_A> form is used when this is the sole argument,	3618	loop argument"). The C<EV_A> form is used when this is the sole argument,
3469	C<EV_A_> is used when other arguments are following. Example:	3619	C<EV_A_> is used when other arguments are following. Example:
3470		3620
3471	ev_unref (EV_A);	3621	ev_unref (EV_A);
3472	ev_timer_add (EV_A_ watcher);	3622	ev_timer_add (EV_A_ watcher);
3473	ev_loop (EV_A_ 0);	3623	ev_run (EV_A_ 0);
3474		3624
3475	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3625	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3476	which is often provided by the following macro.	3626	which is often provided by the following macro.
3477		3627
3478	=item C<EV_P>, C<EV_P_>	3628	=item C<EV_P>, C<EV_P_>
…		…
3518	}	3668	}
3519		3669
3520	ev_check check;	3670	ev_check check;
3521	ev_check_init (&check, check_cb);	3671	ev_check_init (&check, check_cb);
3522	ev_check_start (EV_DEFAULT_ &check);	3672	ev_check_start (EV_DEFAULT_ &check);
3523	ev_loop (EV_DEFAULT_ 0);	3673	ev_run (EV_DEFAULT_ 0);
3524		3674
3525	=head1 EMBEDDING	3675	=head1 EMBEDDING
3526		3676
3527	Libev can (and often is) directly embedded into host	3677	Libev can (and often is) directly embedded into host
3528	applications. Examples of applications that embed it include the Deliantra	3678	applications. Examples of applications that embed it include the Deliantra
…		…
3608	libev.m4	3758	libev.m4
3609		3759
3610	=head2 PREPROCESSOR SYMBOLS/MACROS	3760	=head2 PREPROCESSOR SYMBOLS/MACROS
3611		3761
3612	Libev can be configured via a variety of preprocessor symbols you have to	3762	Libev can be configured via a variety of preprocessor symbols you have to
3613	define before including any of its files. The default in the absence of	3763	define before including (or compiling) any of its files. The default in
3614	autoconf is documented for every option.	3764	the absence of autoconf is documented for every option.
		3765
		3766	Symbols marked with "(h)" do not change the ABI, and can have different
		3767	values when compiling libev vs. including F<ev.h>, so it is permissible
		3768	to redefine them before including F<ev.h> without breaking compatibility
		3769	to a compiled library. All other symbols change the ABI, which means all
		3770	users of libev and the libev code itself must be compiled with compatible
		3771	settings.
3615		3772
3616	=over 4	3773	=over 4
3617		3774
		3775	=item EV_COMPAT3 (h)
		3776
		3777	Backwards compatibility is a major concern for libev. This is why this
		3778	release of libev comes with wrappers for the functions and symbols that
		3779	have been renamed between libev version 3 and 4.
		3780
		3781	You can disable these wrappers (to test compatibility with future
		3782	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3783	sources. This has the additional advantage that you can drop the C<struct>
		3784	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3785	typedef in that case.
		3786
		3787	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3788	and in some even more future version the compatibility code will be
		3789	removed completely.
		3790
3618	=item EV_STANDALONE	3791	=item EV_STANDALONE (h)
3619		3792
3620	Must always be C<1> if you do not use autoconf configuration, which	3793	Must always be C<1> if you do not use autoconf configuration, which
3621	keeps libev from including F<config.h>, and it also defines dummy	3794	keeps libev from including F<config.h>, and it also defines dummy
3622	implementations for some libevent functions (such as logging, which is not	3795	implementations for some libevent functions (such as logging, which is not
3623	supported). It will also not define any of the structs usually found in	3796	supported). It will also not define any of the structs usually found in
…		…
3773	as well as for signal and thread safety in C<ev_async> watchers.	3946	as well as for signal and thread safety in C<ev_async> watchers.
3774		3947
3775	In the absence of this define, libev will use C<sig_atomic_t volatile>	3948	In the absence of this define, libev will use C<sig_atomic_t volatile>
3776	(from F<signal.h>), which is usually good enough on most platforms.	3949	(from F<signal.h>), which is usually good enough on most platforms.
3777		3950
3778	=item EV_H	3951	=item EV_H (h)
3779		3952
3780	The name of the F<ev.h> header file used to include it. The default if	3953	The name of the F<ev.h> header file used to include it. The default if
3781	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be	3954	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
3782	used to virtually rename the F<ev.h> header file in case of conflicts.	3955	used to virtually rename the F<ev.h> header file in case of conflicts.
3783		3956
3784	=item EV_CONFIG_H	3957	=item EV_CONFIG_H (h)
3785		3958
3786	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	3959	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
3787	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	3960	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
3788	C<EV_H>, above.	3961	C<EV_H>, above.
3789		3962
3790	=item EV_EVENT_H	3963	=item EV_EVENT_H (h)
3791		3964
3792	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	3965	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
3793	of how the F<event.h> header can be found, the default is C<"event.h">.	3966	of how the F<event.h> header can be found, the default is C<"event.h">.
3794		3967
3795	=item EV_PROTOTYPES	3968	=item EV_PROTOTYPES (h)
3796		3969
3797	If defined to be C<0>, then F<ev.h> will not define any function	3970	If defined to be C<0>, then F<ev.h> will not define any function
3798	prototypes, but still define all the structs and other symbols. This is	3971	prototypes, but still define all the structs and other symbols. This is
3799	occasionally useful if you want to provide your own wrapper functions	3972	occasionally useful if you want to provide your own wrapper functions
3800	around libev functions.	3973	around libev functions.
…		…
3822	fine.	3995	fine.
3823		3996
3824	If your embedding application does not need any priorities, defining these	3997	If your embedding application does not need any priorities, defining these
3825	both to C<0> will save some memory and CPU.	3998	both to C<0> will save some memory and CPU.
3826		3999
3827	=item EV_PERIODIC_ENABLE	4000	=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
		4001	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
		4002	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3828		4003
3829	If undefined or defined to be C<1>, then periodic timers are supported. If	4004	If undefined or defined to be C<1> (and the platform supports it), then
3830	defined to be C<0>, then they are not. Disabling them saves a few kB of	4005	the respective watcher type is supported. If defined to be C<0>, then it
3831	code.	4006	is not. Disabling watcher types mainly saves code size.
3832		4007
3833	=item EV_IDLE_ENABLE	4008	=item EV_FEATURES
3834
3835	If undefined or defined to be C<1>, then idle watchers are supported. If
3836	defined to be C<0>, then they are not. Disabling them saves a few kB of
3837	code.
3838
3839	=item EV_EMBED_ENABLE
3840
3841	If undefined or defined to be C<1>, then embed watchers are supported. If
3842	defined to be C<0>, then they are not. Embed watchers rely on most other
3843	watcher types, which therefore must not be disabled.
3844
3845	=item EV_STAT_ENABLE
3846
3847	If undefined or defined to be C<1>, then stat watchers are supported. If
3848	defined to be C<0>, then they are not.
3849
3850	=item EV_FORK_ENABLE
3851
3852	If undefined or defined to be C<1>, then fork watchers are supported. If
3853	defined to be C<0>, then they are not.
3854
3855	=item EV_ASYNC_ENABLE
3856
3857	If undefined or defined to be C<1>, then async watchers are supported. If
3858	defined to be C<0>, then they are not.
3859
3860	=item EV_MINIMAL
3861		4009
3862	If you need to shave off some kilobytes of code at the expense of some	4010	If you need to shave off some kilobytes of code at the expense of some
3863	speed (but with the full API), define this symbol to C<1>. Currently this	4011	speed (but with the full API), you can define this symbol to request
3864	is used to override some inlining decisions, saves roughly 30% code size	4012	certain subsets of functionality. The default is to enable all features
3865	on amd64. It also selects a much smaller 2-heap for timer management over	4013	that can be enabled on the platform.
3866	the default 4-heap.
3867		4014
3868	You can save even more by disabling watcher types you do not need	4015	A typical way to use this symbol is to define it to C<0> (or to a bitset
3869	and setting C<EV_MAXPRI> == C<EV_MINPRI>. Also, disabling C<assert>	4016	with some broad features you want) and then selectively re-enable
3870	(C<-DNDEBUG>) will usually reduce code size a lot.	4017	additional parts you want, for example if you want everything minimal,
		4018	but multiple event loop support, async and child watchers and the poll
		4019	backend, use this:
3871		4020
3872	Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to	4021	#define EV_FEATURES 0
3873	provide a bare-bones event library. See C<ev.h> for details on what parts	4022	#define EV_MULTIPLICITY 1
3874	of the API are still available, and do not complain if this subset changes	4023	#define EV_USE_POLL 1
3875	over time.	4024	#define EV_CHILD_ENABLE 1
		4025	#define EV_ASYNC_ENABLE 1
		4026
		4027	The actual value is a bitset, it can be a combination of the following
		4028	values:
		4029
		4030	=over 4
		4031
		4032	=item C<1> - faster/larger code
		4033
		4034	Use larger code to speed up some operations.
		4035
		4036	Currently this is used to override some inlining decisions (enlarging the
		4037	code size by roughly 30% on amd64).
		4038
		4039	When optimising for size, use of compiler flags such as C<-Os> with
		4040	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
		4041	assertions.
		4042
		4043	=item C<2> - faster/larger data structures
		4044
		4045	Replaces the small 2-heap for timer management by a faster 4-heap, larger
		4046	hash table sizes and so on. This will usually further increase code size
		4047	and can additionally have an effect on the size of data structures at
		4048	runtime.
		4049
		4050	=item C<4> - full API configuration
		4051
		4052	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
		4053	enables multiplicity (C<EV_MULTIPLICITY>=1).
		4054
		4055	=item C<8> - full API
		4056
		4057	This enables a lot of the "lesser used" API functions. See C<ev.h> for
		4058	details on which parts of the API are still available without this
		4059	feature, and do not complain if this subset changes over time.
		4060
		4061	=item C<16> - enable all optional watcher types
		4062
		4063	Enables all optional watcher types. If you want to selectively enable
		4064	only some watcher types other than I/O and timers (e.g. prepare,
		4065	embed, async, child...) you can enable them manually by defining
		4066	C<EV_watchertype_ENABLE> to C<1> instead.
		4067
		4068	=item C<32> - enable all backends
		4069
		4070	This enables all backends - without this feature, you need to enable at
		4071	least one backend manually (C<EV_USE_SELECT> is a good choice).
		4072
		4073	=item C<64> - enable OS-specific "helper" APIs
		4074
		4075	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
		4076	default.
		4077
		4078	=back
		4079
		4080	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
		4081	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
		4082	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
		4083	watchers, timers and monotonic clock support.
		4084
		4085	With an intelligent-enough linker (gcc+binutils are intelligent enough
		4086	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
		4087	your program might be left out as well - a binary starting a timer and an
		4088	I/O watcher then might come out at only 5Kb.
		4089
		4090	=item EV_AVOID_STDIO
		4091
		4092	If this is set to C<1> at compiletime, then libev will avoid using stdio
		4093	functions (printf, scanf, perror etc.). This will increase the code size
		4094	somewhat, but if your program doesn't otherwise depend on stdio and your
		4095	libc allows it, this avoids linking in the stdio library which is quite
		4096	big.
		4097
		4098	Note that error messages might become less precise when this option is
		4099	enabled.
3876		4100
3877	=item EV_NSIG	4101	=item EV_NSIG
3878		4102
3879	The highest supported signal number, +1 (or, the number of	4103	The highest supported signal number, +1 (or, the number of
3880	signals): Normally, libev tries to deduce the maximum number of signals	4104	signals): Normally, libev tries to deduce the maximum number of signals
3881	automatically, but sometimes this fails, in which case it can be	4105	automatically, but sometimes this fails, in which case it can be
3882	specified. Also, using a lower number than detected (C<32> should be	4106	specified. Also, using a lower number than detected (C<32> should be
3883	good for about any system in existance) can save some memory, as libev	4107	good for about any system in existence) can save some memory, as libev
3884	statically allocates some 12-24 bytes per signal number.	4108	statically allocates some 12-24 bytes per signal number.
3885		4109
3886	=item EV_PID_HASHSIZE	4110	=item EV_PID_HASHSIZE
3887		4111
3888	C<ev_child> watchers use a small hash table to distribute workload by	4112	C<ev_child> watchers use a small hash table to distribute workload by
3889	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	4113	pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
3890	than enough. If you need to manage thousands of children you might want to	4114	usually more than enough. If you need to manage thousands of children you
3891	increase this value (I<must> be a power of two).	4115	might want to increase this value (I<must> be a power of two).
3892		4116
3893	=item EV_INOTIFY_HASHSIZE	4117	=item EV_INOTIFY_HASHSIZE
3894		4118
3895	C<ev_stat> watchers use a small hash table to distribute workload by	4119	C<ev_stat> watchers use a small hash table to distribute workload by
3896	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	4120	inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
3897	usually more than enough. If you need to manage thousands of C<ev_stat>	4121	disabled), usually more than enough. If you need to manage thousands of
3898	watchers you might want to increase this value (I<must> be a power of	4122	C<ev_stat> watchers you might want to increase this value (I<must> be a
3899	two).	4123	power of two).
3900		4124
3901	=item EV_USE_4HEAP	4125	=item EV_USE_4HEAP
3902		4126
3903	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4127	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3904	timer and periodics heaps, libev uses a 4-heap when this symbol is defined	4128	timer and periodics heaps, libev uses a 4-heap when this symbol is defined
3905	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably	4129	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
3906	faster performance with many (thousands) of watchers.	4130	faster performance with many (thousands) of watchers.
3907		4131
3908	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4132	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3909	(disabled).	4133	will be C<0>.
3910		4134
3911	=item EV_HEAP_CACHE_AT	4135	=item EV_HEAP_CACHE_AT
3912		4136
3913	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4137	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3914	timer and periodics heaps, libev can cache the timestamp (I<at>) within	4138	timer and periodics heaps, libev can cache the timestamp (I<at>) within
3915	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	4139	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3916	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	4140	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3917	but avoids random read accesses on heap changes. This improves performance	4141	but avoids random read accesses on heap changes. This improves performance
3918	noticeably with many (hundreds) of watchers.	4142	noticeably with many (hundreds) of watchers.
3919		4143
3920	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4144	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3921	(disabled).	4145	will be C<0>.
3922		4146
3923	=item EV_VERIFY	4147	=item EV_VERIFY
3924		4148
3925	Controls how much internal verification (see C<ev_loop_verify ()>) will	4149	Controls how much internal verification (see C<ev_verify ()>) will
3926	be done: If set to C<0>, no internal verification code will be compiled	4150	be done: If set to C<0>, no internal verification code will be compiled
3927	in. If set to C<1>, then verification code will be compiled in, but not	4151	in. If set to C<1>, then verification code will be compiled in, but not
3928	called. If set to C<2>, then the internal verification code will be	4152	called. If set to C<2>, then the internal verification code will be
3929	called once per loop, which can slow down libev. If set to C<3>, then the	4153	called once per loop, which can slow down libev. If set to C<3>, then the
3930	verification code will be called very frequently, which will slow down	4154	verification code will be called very frequently, which will slow down
3931	libev considerably.	4155	libev considerably.
3932		4156
3933	The default is C<1>, unless C<EV_MINIMAL> is set, in which case it will be	4157	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3934	C<0>.	4158	will be C<0>.
3935		4159
3936	=item EV_COMMON	4160	=item EV_COMMON
3937		4161
3938	By default, all watchers have a C<void *data> member. By redefining	4162	By default, all watchers have a C<void *data> member. By redefining
3939	this macro to a something else you can include more and other types of	4163	this macro to something else you can include more and other types of
3940	members. You have to define it each time you include one of the files,	4164	members. You have to define it each time you include one of the files,
3941	though, and it must be identical each time.	4165	though, and it must be identical each time.
3942		4166
3943	For example, the perl EV module uses something like this:	4167	For example, the perl EV module uses something like this:
3944		4168
…		…
3997	file.	4221	file.
3998		4222
3999	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4223	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
4000	that everybody includes and which overrides some configure choices:	4224	that everybody includes and which overrides some configure choices:
4001		4225
4002	#define EV_MINIMAL 1	4226	#define EV_FEATURES 8
4003	#define EV_USE_POLL 0	4227	#define EV_USE_SELECT 1
4004	#define EV_MULTIPLICITY 0
4005	#define EV_PERIODIC_ENABLE 0	4228	#define EV_PREPARE_ENABLE 1
		4229	#define EV_IDLE_ENABLE 1
4006	#define EV_STAT_ENABLE 0	4230	#define EV_SIGNAL_ENABLE 1
4007	#define EV_FORK_ENABLE 0	4231	#define EV_CHILD_ENABLE 1
		4232	#define EV_USE_STDEXCEPT 0
4008	#define EV_CONFIG_H <config.h>	4233	#define EV_CONFIG_H <config.h>
4009	#define EV_MINPRI 0
4010	#define EV_MAXPRI 0
4011		4234
4012	#include "ev++.h"	4235	#include "ev++.h"
4013		4236
4014	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4237	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
4015		4238
…		…
4146	userdata *u = ev_userdata (EV_A);	4369	userdata *u = ev_userdata (EV_A);
4147	pthread_mutex_lock (&u->lock);	4370	pthread_mutex_lock (&u->lock);
4148	}	4371	}
4149		4372
4150	The event loop thread first acquires the mutex, and then jumps straight	4373	The event loop thread first acquires the mutex, and then jumps straight
4151	into C<ev_loop>:	4374	into C<ev_run>:
4152		4375
4153	void *	4376	void *
4154	l_run (void *thr_arg)	4377	l_run (void *thr_arg)
4155	{	4378	{
4156	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4379	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4157		4380
4158	l_acquire (EV_A);	4381	l_acquire (EV_A);
4159	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4382	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4160	ev_loop (EV_A_ 0);	4383	ev_run (EV_A_ 0);
4161	l_release (EV_A);	4384	l_release (EV_A);
4162		4385
4163	return 0;	4386	return 0;
4164	}	4387	}
4165		4388
…		…
4217		4440
4218	=head3 COROUTINES	4441	=head3 COROUTINES
4219		4442
4220	Libev is very accommodating to coroutines ("cooperative threads"):	4443	Libev is very accommodating to coroutines ("cooperative threads"):
4221	libev fully supports nesting calls to its functions from different	4444	libev fully supports nesting calls to its functions from different
4222	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4445	coroutines (e.g. you can call C<ev_run> on the same loop from two
4223	different coroutines, and switch freely between both coroutines running	4446	different coroutines, and switch freely between both coroutines running
4224	the loop, as long as you don't confuse yourself). The only exception is	4447	the loop, as long as you don't confuse yourself). The only exception is
4225	that you must not do this from C<ev_periodic> reschedule callbacks.	4448	that you must not do this from C<ev_periodic> reschedule callbacks.
4226		4449
4227	Care has been taken to ensure that libev does not keep local state inside	4450	Care has been taken to ensure that libev does not keep local state inside
4228	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4451	C<ev_run>, and other calls do not usually allow for coroutine switches as
4229	they do not call any callbacks.	4452	they do not call any callbacks.
4230		4453
4231	=head2 COMPILER WARNINGS	4454	=head2 COMPILER WARNINGS
4232		4455
4233	Depending on your compiler and compiler settings, you might get no or a	4456	Depending on your compiler and compiler settings, you might get no or a
…		…
4244	maintainable.	4467	maintainable.
4245		4468
4246	And of course, some compiler warnings are just plain stupid, or simply	4469	And of course, some compiler warnings are just plain stupid, or simply
4247	wrong (because they don't actually warn about the condition their message	4470	wrong (because they don't actually warn about the condition their message
4248	seems to warn about). For example, certain older gcc versions had some	4471	seems to warn about). For example, certain older gcc versions had some
4249	warnings that resulted an extreme number of false positives. These have	4472	warnings that resulted in an extreme number of false positives. These have
4250	been fixed, but some people still insist on making code warn-free with	4473	been fixed, but some people still insist on making code warn-free with
4251	such buggy versions.	4474	such buggy versions.
4252		4475
4253	While libev is written to generate as few warnings as possible,	4476	While libev is written to generate as few warnings as possible,
4254	"warn-free" code is not a goal, and it is recommended not to build libev	4477	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4290	I suggest using suppression lists.	4513	I suggest using suppression lists.
4291		4514
4292		4515
4293	=head1 PORTABILITY NOTES	4516	=head1 PORTABILITY NOTES
4294		4517
		4518	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4519
		4520	GNU/Linux is the only common platform that supports 64 bit file/large file
		4521	interfaces but I<disables> them by default.
		4522
		4523	That means that libev compiled in the default environment doesn't support
		4524	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4525
		4526	Unfortunately, many programs try to work around this GNU/Linux issue
		4527	by enabling the large file API, which makes them incompatible with the
		4528	standard libev compiled for their system.
		4529
		4530	Likewise, libev cannot enable the large file API itself as this would
		4531	suddenly make it incompatible to the default compile time environment,
		4532	i.e. all programs not using special compile switches.
		4533
		4534	=head2 OS/X AND DARWIN BUGS
		4535
		4536	The whole thing is a bug if you ask me - basically any system interface
		4537	you touch is broken, whether it is locales, poll, kqueue or even the
		4538	OpenGL drivers.
		4539
		4540	=head3 C<kqueue> is buggy
		4541
		4542	The kqueue syscall is broken in all known versions - most versions support
		4543	only sockets, many support pipes.
		4544
		4545	Libev tries to work around this by not using C<kqueue> by default on this
		4546	rotten platform, but of course you can still ask for it when creating a
		4547	loop - embedding a socket-only kqueue loop into a select-based one is
		4548	probably going to work well.
		4549
		4550	=head3 C<poll> is buggy
		4551
		4552	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4553	implementation by something calling C<kqueue> internally around the 10.5.6
		4554	release, so now C<kqueue> I<and> C<poll> are broken.
		4555
		4556	Libev tries to work around this by not using C<poll> by default on
		4557	this rotten platform, but of course you can still ask for it when creating
		4558	a loop.
		4559
		4560	=head3 C<select> is buggy
		4561
		4562	All that's left is C<select>, and of course Apple found a way to fuck this
		4563	one up as well: On OS/X, C<select> actively limits the number of file
		4564	descriptors you can pass in to 1024 - your program suddenly crashes when
		4565	you use more.
		4566
		4567	There is an undocumented "workaround" for this - defining
		4568	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4569	work on OS/X.
		4570
		4571	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4572
		4573	=head3 C<errno> reentrancy
		4574
		4575	The default compile environment on Solaris is unfortunately so
		4576	thread-unsafe that you can't even use components/libraries compiled
		4577	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4578	defined by default. A valid, if stupid, implementation choice.
		4579
		4580	If you want to use libev in threaded environments you have to make sure
		4581	it's compiled with C<_REENTRANT> defined.
		4582
		4583	=head3 Event port backend
		4584
		4585	The scalable event interface for Solaris is called "event
		4586	ports". Unfortunately, this mechanism is very buggy in all major
		4587	releases. If you run into high CPU usage, your program freezes or you get
		4588	a large number of spurious wakeups, make sure you have all the relevant
		4589	and latest kernel patches applied. No, I don't know which ones, but there
		4590	are multiple ones to apply, and afterwards, event ports actually work
		4591	great.
		4592
		4593	If you can't get it to work, you can try running the program by setting
		4594	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4595	C<select> backends.
		4596
		4597	=head2 AIX POLL BUG
		4598
		4599	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4600	this by trying to avoid the poll backend altogether (i.e. it's not even
		4601	compiled in), which normally isn't a big problem as C<select> works fine
		4602	with large bitsets on AIX, and AIX is dead anyway.
		4603
4295	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4604	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4605
		4606	=head3 General issues
4296		4607
4297	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4608	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4298	requires, and its I/O model is fundamentally incompatible with the POSIX	4609	requires, and its I/O model is fundamentally incompatible with the POSIX
4299	model. Libev still offers limited functionality on this platform in	4610	model. Libev still offers limited functionality on this platform in
4300	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4611	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4301	descriptors. This only applies when using Win32 natively, not when using	4612	descriptors. This only applies when using Win32 natively, not when using
4302	e.g. cygwin.	4613	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4614	as every compielr comes with a slightly differently broken/incompatible
		4615	environment.
4303		4616
4304	Lifting these limitations would basically require the full	4617	Lifting these limitations would basically require the full
4305	re-implementation of the I/O system. If you are into these kinds of	4618	re-implementation of the I/O system. If you are into this kind of thing,
4306	things, then note that glib does exactly that for you in a very portable	4619	then note that glib does exactly that for you in a very portable way (note
4307	way (note also that glib is the slowest event library known to man).	4620	also that glib is the slowest event library known to man).
4308		4621
4309	There is no supported compilation method available on windows except	4622	There is no supported compilation method available on windows except
4310	embedding it into other applications.	4623	embedding it into other applications.
4311		4624
4312	Sensible signal handling is officially unsupported by Microsoft - libev	4625	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4340	you do I<not> compile the F<ev.c> or any other embedded source files!):	4653	you do I<not> compile the F<ev.c> or any other embedded source files!):
4341		4654
4342	#include "evwrap.h"	4655	#include "evwrap.h"
4343	#include "ev.c"	4656	#include "ev.c"
4344		4657
4345	=over 4
4346
4347	=item The winsocket select function	4658	=head3 The winsocket C<select> function
4348		4659
4349	The winsocket C<select> function doesn't follow POSIX in that it	4660	The winsocket C<select> function doesn't follow POSIX in that it
4350	requires socket I<handles> and not socket I<file descriptors> (it is	4661	requires socket I<handles> and not socket I<file descriptors> (it is
4351	also extremely buggy). This makes select very inefficient, and also	4662	also extremely buggy). This makes select very inefficient, and also
4352	requires a mapping from file descriptors to socket handles (the Microsoft	4663	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4361	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4672	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4362		4673
4363	Note that winsockets handling of fd sets is O(n), so you can easily get a	4674	Note that winsockets handling of fd sets is O(n), so you can easily get a
4364	complexity in the O(n²) range when using win32.	4675	complexity in the O(n²) range when using win32.
4365		4676
4366	=item Limited number of file descriptors	4677	=head3 Limited number of file descriptors
4367		4678
4368	Windows has numerous arbitrary (and low) limits on things.	4679	Windows has numerous arbitrary (and low) limits on things.
4369		4680
4370	Early versions of winsocket's select only supported waiting for a maximum	4681	Early versions of winsocket's select only supported waiting for a maximum
4371	of C<64> handles (probably owning to the fact that all windows kernels	4682	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4386	runtime libraries. This might get you to about C<512> or C<2048> sockets	4697	runtime libraries. This might get you to about C<512> or C<2048> sockets
4387	(depending on windows version and/or the phase of the moon). To get more,	4698	(depending on windows version and/or the phase of the moon). To get more,
4388	you need to wrap all I/O functions and provide your own fd management, but	4699	you need to wrap all I/O functions and provide your own fd management, but
4389	the cost of calling select (O(n²)) will likely make this unworkable.	4700	the cost of calling select (O(n²)) will likely make this unworkable.
4390		4701
4391	=back
4392
4393	=head2 PORTABILITY REQUIREMENTS	4702	=head2 PORTABILITY REQUIREMENTS
4394		4703
4395	In addition to a working ISO-C implementation and of course the	4704	In addition to a working ISO-C implementation and of course the
4396	backend-specific APIs, libev relies on a few additional extensions:	4705	backend-specific APIs, libev relies on a few additional extensions:
4397		4706
…		…
4435	watchers.	4744	watchers.
4436		4745
4437	=item C<double> must hold a time value in seconds with enough accuracy	4746	=item C<double> must hold a time value in seconds with enough accuracy
4438		4747
4439	The type C<double> is used to represent timestamps. It is required to	4748	The type C<double> is used to represent timestamps. It is required to
4440	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4749	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4441	enough for at least into the year 4000. This requirement is fulfilled by	4750	good enough for at least into the year 4000 with millisecond accuracy
		4751	(the design goal for libev). This requirement is overfulfilled by
4442	implementations implementing IEEE 754, which is basically all existing	4752	implementations using IEEE 754, which is basically all existing ones. With
4443	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4753	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4444	2200.
4445		4754
4446	=back	4755	=back
4447		4756
4448	If you know of other additional requirements drop me a note.	4757	If you know of other additional requirements drop me a note.
4449		4758
…		…
4517	involves iterating over all running async watchers or all signal numbers.	4826	involves iterating over all running async watchers or all signal numbers.
4518		4827
4519	=back	4828	=back
4520		4829
4521		4830
		4831	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4832
		4833	The major version 4 introduced some minor incompatible changes to the API.
		4834
		4835	At the moment, the C<ev.h> header file tries to implement superficial
		4836	compatibility, so most programs should still compile. Those might be
		4837	removed in later versions of libev, so better update early than late.
		4838
		4839	=over 4
		4840
		4841	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4842
		4843	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4844
		4845	ev_loop_destroy (EV_DEFAULT);
		4846	ev_loop_fork (EV_DEFAULT);
		4847
		4848	=item function/symbol renames
		4849
		4850	A number of functions and symbols have been renamed:
		4851
		4852	ev_loop => ev_run
		4853	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4854	EVLOOP_ONESHOT => EVRUN_ONCE
		4855
		4856	ev_unloop => ev_break
		4857	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4858	EVUNLOOP_ONE => EVBREAK_ONE
		4859	EVUNLOOP_ALL => EVBREAK_ALL
		4860
		4861	EV_TIMEOUT => EV_TIMER
		4862
		4863	ev_loop_count => ev_iteration
		4864	ev_loop_depth => ev_depth
		4865	ev_loop_verify => ev_verify
		4866
		4867	Most functions working on C<struct ev_loop> objects don't have an
		4868	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4869	associated constants have been renamed to not collide with the C<struct
		4870	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4871	as all other watcher types. Note that C<ev_loop_fork> is still called
		4872	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4873	typedef.
		4874
		4875	=item C<EV_COMPAT3> backwards compatibility mechanism
		4876
		4877	The backward compatibility mechanism can be controlled by
		4878	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4879	section.
		4880
		4881	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4882
		4883	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4884	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4885	and work, but the library code will of course be larger.
		4886
		4887	=back
		4888
		4889
4522	=head1 GLOSSARY	4890	=head1 GLOSSARY
4523		4891
4524	=over 4	4892	=over 4
4525		4893
4526	=item active	4894	=item active
4527		4895
4528	A watcher is active as long as it has been started (has been attached to	4896	A watcher is active as long as it has been started and not yet stopped.
4529	an event loop) but not yet stopped (disassociated from the event loop).	4897	See L<WATCHER STATES> for details.
4530		4898
4531	=item application	4899	=item application
4532		4900
4533	In this document, an application is whatever is using libev.	4901	In this document, an application is whatever is using libev.
		4902
		4903	=item backend
		4904
		4905	The part of the code dealing with the operating system interfaces.
4534		4906
4535	=item callback	4907	=item callback
4536		4908
4537	The address of a function that is called when some event has been	4909	The address of a function that is called when some event has been
4538	detected. Callbacks are being passed the event loop, the watcher that	4910	detected. Callbacks are being passed the event loop, the watcher that
4539	received the event, and the actual event bitset.	4911	received the event, and the actual event bitset.
4540		4912
4541	=item callback invocation	4913	=item callback/watcher invocation
4542		4914
4543	The act of calling the callback associated with a watcher.	4915	The act of calling the callback associated with a watcher.
4544		4916
4545	=item event	4917	=item event
4546		4918
4547	A change of state of some external event, such as data now being available	4919	A change of state of some external event, such as data now being available
4548	for reading on a file descriptor, time having passed or simply not having	4920	for reading on a file descriptor, time having passed or simply not having
4549	any other events happening anymore.	4921	any other events happening anymore.
4550		4922
4551	In libev, events are represented as single bits (such as C<EV_READ> or	4923	In libev, events are represented as single bits (such as C<EV_READ> or
4552	C<EV_TIMEOUT>).	4924	C<EV_TIMER>).
4553		4925
4554	=item event library	4926	=item event library
4555		4927
4556	A software package implementing an event model and loop.	4928	A software package implementing an event model and loop.
4557		4929
…		…
4565	The model used to describe how an event loop handles and processes	4937	The model used to describe how an event loop handles and processes
4566	watchers and events.	4938	watchers and events.
4567		4939
4568	=item pending	4940	=item pending
4569		4941
4570	A watcher is pending as soon as the corresponding event has been detected,	4942	A watcher is pending as soon as the corresponding event has been
4571	and stops being pending as soon as the watcher will be invoked or its	4943	detected. See L<WATCHER STATES> for details.
4572	pending status is explicitly cleared by the application.
4573
4574	A watcher can be pending, but not active. Stopping a watcher also clears
4575	its pending status.
4576		4944
4577	=item real time	4945	=item real time
4578		4946
4579	The physical time that is observed. It is apparently strictly monotonic :)	4947	The physical time that is observed. It is apparently strictly monotonic :)
4580		4948
…		…
4587	=item watcher	4955	=item watcher
4588		4956
4589	A data structure that describes interest in certain events. Watchers need	4957	A data structure that describes interest in certain events. Watchers need
4590	to be started (attached to an event loop) before they can receive events.	4958	to be started (attached to an event loop) before they can receive events.
4591		4959
4592	=item watcher invocation
4593
4594	The act of calling the callback associated with a watcher.
4595
4596	=back	4960	=back
4597		4961
4598	=head1 AUTHOR	4962	=head1 AUTHOR
4599		4963
4600	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4964	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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