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Revision 1.275 by root, Sat Dec 26 09:21:54 2009 UTC vs.
Revision 1.322 by root, Sun Oct 24 17:58:41 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	Example: Use whatever libev has to offer, but make sure that kqueue is
		348	used if available (warning, breaks stuff, best use only with your own
		349	private event loop and only if you know the OS supports your types of
		350	fds):
		351
		352	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
		353
		354	=item struct ev_loop *ev_loop_new (unsigned int flags)
		355
		356	This will create and initialise a new event loop object. If the loop
		357	could not be initialised, returns false.
		358
		359	Note that this function I<is> thread-safe, and one common way to use
		360	libev with threads is indeed to create one loop per thread, and using the
		361	default loop in the "main" or "initial" thread.
326		362
327	The flags argument can be used to specify special behaviour or specific	363	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>).	364	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
329		365
330	The following flags are supported:	366	The following flags are supported:
…		…
345	useful to try out specific backends to test their performance, or to work	381	useful to try out specific backends to test their performance, or to work
346	around bugs.	382	around bugs.
347		383
348	=item C<EVFLAG_FORKCHECK>	384	=item C<EVFLAG_FORKCHECK>
349		385
350	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	386	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	387	make libev check for a fork in each iteration by enabling this flag.
352	enabling this flag.
353		388
354	This works by calling C<getpid ()> on every iteration of the loop,	389	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	390	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	391	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	392	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	405	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	406	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	407	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.	408	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
374		409
375	=item C<EVFLAG_NOSIGFD>	410	=item C<EVFLAG_SIGNALFD>
376		411
377	When this flag is specified, then libev will not attempt to use the	412	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	413	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	414	delivers signals synchronously, which makes it both faster and might make
380	flag might go away once the signalfd functionality is considered stable,	415	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.	416	handling with threads, as long as you properly block signals in your
		417	threads that are not interested in handling them.
		418
		419	Signalfd will not be used by default as this changes your signal mask, and
		420	there are a lot of shoddy libraries and programs (glib's threadpool for
		421	example) that can't properly initialise their signal masks.
382		422
383	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	423	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
384		424
385	This is your standard select(2) backend. Not I<completely> standard, as	425	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,	426	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	474	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	475	I<different> file descriptors (even already closed ones, so one cannot
436	even remove them from the set) than registered in the set (especially	476	even remove them from the set) than registered in the set (especially
437	on SMP systems). Libev tries to counter these spurious notifications by	477	on SMP systems). Libev tries to counter these spurious notifications by
438	employing an additional generation counter and comparing that against the	478	employing an additional generation counter and comparing that against the
439	events to filter out spurious ones, recreating the set when required.	479	events to filter out spurious ones, recreating the set when required. Last
		480	not least, it also refuses to work with some file descriptors which work
		481	perfectly fine with C<select> (files, many character devices...).
440		482
441	While stopping, setting and starting an I/O watcher in the same iteration	483	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	484	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	485	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	486	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,	584	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	585	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	586	here). If none are specified, all backends in C<ev_recommended_backends
545	()> will be tried.	587	()> will be tried.
546		588
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.	589	Example: Try to create a event loop that uses epoll and nothing else.
576		590
577	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	591	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
578	if (!epoller)	592	if (!epoller)
579	fatal ("no epoll found here, maybe it hides under your chair");	593	fatal ("no epoll found here, maybe it hides under your chair");
580		594
581	=item ev_default_destroy ()	595	=item ev_loop_destroy (loop)
582		596
583	Destroys the default loop again (frees all memory and kernel state	597	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	598	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	599	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>	600	responsibility to either stop all watchers cleanly yourself I<before>
587	calling this function, or cope with the fact afterwards (which is usually	601	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	602	the easiest thing, you can just ignore the watchers and/or C<free ()> them
…		…
590		604
591	Note that certain global state, such as signal state (and installed signal	605	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	606	handlers), will not be freed by this function, and related watchers (such
593	as signal and child watchers) would need to be stopped manually.	607	as signal and child watchers) would need to be stopped manually.
594		608
595	In general it is not advisable to call this function except in the	609	This function is normally used on loop objects allocated by
596	rare occasion where you really need to free e.g. the signal handling	610	C<ev_loop_new>, but it can also be used on the default loop returned by
		611	C<ev_default_loop>, in which case it is not thread-safe.
		612
		613	Note that it is not advisable to call this function on the default loop
		614	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	615	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>.	616	and C<ev_loop_destroy>.
599		617
600	=item ev_loop_destroy (loop)	618	=item ev_loop_fork (loop)
601		619
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	620	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	621	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	622	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	623	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	624	child before resuming or calling C<ev_run>.
612	functions, and it will only take effect at the next C<ev_loop> iteration.	625
		626	Again, you I<have> to call it on I<any> loop that you want to re-use after
		627	a fork, I<even if you do not plan to use the loop in the parent>. This is
		628	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
		629	during fork.
613		630
614	On the other hand, you only need to call this function in the child	631	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	632	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.	633	you just fork+exec or create a new loop in the child, you don't have to
		634	call it at all (in fact, C<epoll> is so badly broken that it makes a
		635	difference, but libev will usually detect this case on its own and do a
		636	costly reset of the backend).
617		637
618	The function itself is quite fast and it's usually not a problem to call	638	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	639	it just in case after a fork.
620	quite nicely into a call to C<pthread_atfork>:
621		640
		641	Example: Automate calling C<ev_loop_fork> on the default loop when
		642	using pthreads.
		643
		644	static void
		645	post_fork_child (void)
		646	{
		647	ev_loop_fork (EV_DEFAULT);
		648	}
		649
		650	...
622	pthread_atfork (0, 0, ev_default_fork);	651	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		652
631	=item int ev_is_default_loop (loop)	653	=item int ev_is_default_loop (loop)
632		654
633	Returns true when the given loop is, in fact, the default loop, and false	655	Returns true when the given loop is, in fact, the default loop, and false
634	otherwise.	656	otherwise.
635		657
636	=item unsigned int ev_loop_count (loop)	658	=item unsigned int ev_iteration (loop)
637		659
638	Returns the count of loop iterations for the loop, which is identical to	660	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	661	to the number of times libev did poll for new events. It starts at C<0>
640	happily wraps around with enough iterations.	662	and happily wraps around with enough iterations.
641		663
642	This value can sometimes be useful as a generation counter of sorts (it	664	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	665	"ticks" the number of loop iterations), as it roughly corresponds with
644	C<ev_prepare> and C<ev_check> calls.	666	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		667	prepare and check phases.
645		668
646	=item unsigned int ev_loop_depth (loop)	669	=item unsigned int ev_depth (loop)
647		670
648	Returns the number of times C<ev_loop> was entered minus the number of	671	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.	672	times C<ev_run> was exited, in other words, the recursion depth.
650		673
651	Outside C<ev_loop>, this number is zero. In a callback, this number is	674	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),	675	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
653	in which case it is higher.	676	in which case it is higher.
654		677
655	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	678	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
656	etc.), doesn't count as exit.	679	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		680	ungentleman-like behaviour unless it's really convenient.
657		681
658	=item unsigned int ev_backend (loop)	682	=item unsigned int ev_backend (loop)
659		683
660	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	684	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
661	use.	685	use.
…		…
670		694
671	=item ev_now_update (loop)	695	=item ev_now_update (loop)
672		696
673	Establishes the current time by querying the kernel, updating the time	697	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	698	returned by C<ev_now ()> in the progress. This is a costly operation and
675	is usually done automatically within C<ev_loop ()>.	699	is usually done automatically within C<ev_run ()>.
676		700
677	This function is rarely useful, but when some event callback runs for a	701	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	702	very long time without entering the event loop, updating libev's idea of
679	the current time is a good idea.	703	the current time is a good idea.
680		704
…		…
682		706
683	=item ev_suspend (loop)	707	=item ev_suspend (loop)
684		708
685	=item ev_resume (loop)	709	=item ev_resume (loop)
686		710
687	These two functions suspend and resume a loop, for use when the loop is	711	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.	712	loop is not used for a while and timeouts should not be processed.
689		713
690	A typical use case would be an interactive program such as a game: When	714	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	715	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	716	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>	717	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
695	C<ev_resume> directly afterwards to resume timer processing.	719	C<ev_resume> directly afterwards to resume timer processing.
696		720
697	Effectively, all C<ev_timer> watchers will be delayed by the time spend	721	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	722	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	723	will be rescheduled (that is, they will lose any events that would have
700	occured while suspended).	724	occurred while suspended).
701		725
702	After calling C<ev_suspend> you B<must not> call I<any> function on the	726	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>	727	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>.	728	without a previous call to C<ev_suspend>.
705		729
706	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	730	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
707	event loop time (see C<ev_now_update>).	731	event loop time (see C<ev_now_update>).
708		732
709	=item ev_loop (loop, int flags)	733	=item ev_run (loop, int flags)
710		734
711	Finally, this is it, the event handler. This function usually is called	735	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	736	after you have initialised all your watchers and you want to start
713	handling events.	737	handling events. It will ask the operating system for any new events, call
		738	the watcher callbacks, an then repeat the whole process indefinitely: This
		739	is why event loops are called I<loops>.
714		740
715	If the flags argument is specified as C<0>, it will not return until	741	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.	742	until either no event watchers are active anymore or C<ev_break> was
		743	called.
717		744
718	Please note that an explicit C<ev_unloop> is usually better than	745	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	746	relying on all watchers to be stopped when deciding when a program has
720	finished (especially in interactive programs), but having a program	747	finished (especially in interactive programs), but having a program
721	that automatically loops as long as it has to and no longer by virtue	748	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	749	of relying on its watchers stopping correctly, that is truly a thing of
723	beauty.	750	beauty.
724		751
725	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	752	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	753	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	754	block your process in case there are no events and will return after one
728	the loop.	755	iteration of the loop. This is sometimes useful to poll and handle new
		756	events while doing lengthy calculations, to keep the program responsive.
729		757
730	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	758	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	759	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	760	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	761	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	762	user-registered callback will be called), and will return after one
735	iteration of the loop.	763	iteration of the loop.
736		764
737	This is useful if you are waiting for some external event in conjunction	765	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	766	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	767	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.	768	usually a better approach for this kind of thing.
741		769
742	Here are the gory details of what C<ev_loop> does:	770	Here are the gory details of what C<ev_run> does:
743		771
		772	- Increment loop depth.
		773	- Reset the ev_break status.
744	- Before the first iteration, call any pending watchers.	774	- Before the first iteration, call any pending watchers.
		775	LOOP:
745	* If EVFLAG_FORKCHECK was used, check for a fork.	776	- If EVFLAG_FORKCHECK was used, check for a fork.
746	- If a fork was detected (by any means), queue and call all fork watchers.	777	- If a fork was detected (by any means), queue and call all fork watchers.
747	- Queue and call all prepare watchers.	778	- Queue and call all prepare watchers.
		779	- If ev_break was called, goto FINISH.
748	- If we have been forked, detach and recreate the kernel state	780	- If we have been forked, detach and recreate the kernel state
749	as to not disturb the other process.	781	as to not disturb the other process.
750	- Update the kernel state with all outstanding changes.	782	- Update the kernel state with all outstanding changes.
751	- Update the "event loop time" (ev_now ()).	783	- Update the "event loop time" (ev_now ()).
752	- Calculate for how long to sleep or block, if at all	784	- Calculate for how long to sleep or block, if at all
753	(active idle watchers, EVLOOP_NONBLOCK or not having	785	(active idle watchers, EVRUN_NOWAIT or not having
754	any active watchers at all will result in not sleeping).	786	any active watchers at all will result in not sleeping).
755	- Sleep if the I/O and timer collect interval say so.	787	- Sleep if the I/O and timer collect interval say so.
		788	- Increment loop iteration counter.
756	- Block the process, waiting for any events.	789	- Block the process, waiting for any events.
757	- Queue all outstanding I/O (fd) events.	790	- Queue all outstanding I/O (fd) events.
758	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	791	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
759	- Queue all expired timers.	792	- Queue all expired timers.
760	- Queue all expired periodics.	793	- Queue all expired periodics.
761	- Unless any events are pending now, queue all idle watchers.	794	- Queue all idle watchers with priority higher than that of pending events.
762	- Queue all check watchers.	795	- Queue all check watchers.
763	- Call all queued watchers in reverse order (i.e. check watchers first).	796	- 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	797	Signals and child watchers are implemented as I/O watchers, and will
765	be handled here by queueing them when their watcher gets executed.	798	be handled here by queueing them when their watcher gets executed.
766	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	799	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
767	were used, or there are no active watchers, return, otherwise	800	were used, or there are no active watchers, goto FINISH, otherwise
768	continue with step *.	801	continue with step LOOP.
		802	FINISH:
		803	- Reset the ev_break status iff it was EVBREAK_ONE.
		804	- Decrement the loop depth.
		805	- Return.
769		806
770	Example: Queue some jobs and then loop until no events are outstanding	807	Example: Queue some jobs and then loop until no events are outstanding
771	anymore.	808	anymore.
772		809
773	... queue jobs here, make sure they register event watchers as long	810	... 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..)	811	... as they still have work to do (even an idle watcher will do..)
775	ev_loop (my_loop, 0);	812	ev_run (my_loop, 0);
776	... jobs done or somebody called unloop. yeah!	813	... jobs done or somebody called unloop. yeah!
777		814
778	=item ev_unloop (loop, how)	815	=item ev_break (loop, how)
779		816
780	Can be used to make a call to C<ev_loop> return early (but only after it	817	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	818	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	819	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.	820	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
784		821
785	This "unloop state" will be cleared when entering C<ev_loop> again.	822	This "unloop state" will be cleared when entering C<ev_run> again.
786		823
787	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	824	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
788		825
789	=item ev_ref (loop)	826	=item ev_ref (loop)
790		827
791	=item ev_unref (loop)	828	=item ev_unref (loop)
792		829
793	Ref/unref can be used to add or remove a reference count on the event	830	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	831	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.	832	count is nonzero, C<ev_run> will not return on its own.
796		833
797	If you have a watcher you never unregister that should not keep C<ev_loop>	834	This is useful when you have a watcher that you never intend to
798	from returning, call ev_unref() after starting, and ev_ref() before	835	unregister, but that nevertheless should not keep C<ev_run> from
		836	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
799	stopping it.	837	before stopping it.
800		838
801	As an example, libev itself uses this for its internal signal pipe: It	839	As an example, libev itself uses this for its internal signal pipe: It
802	is not visible to the libev user and should not keep C<ev_loop> from	840	is not visible to the libev user and should not keep C<ev_run> from
803	exiting if no event watchers registered by it are active. It is also an	841	exiting if no event watchers registered by it are active. It is also an
804	excellent way to do this for generic recurring timers or from within	842	excellent way to do this for generic recurring timers or from within
805	third-party libraries. Just remember to I<unref after start> and I<ref	843	third-party libraries. Just remember to I<unref after start> and I<ref
806	before stop> (but only if the watcher wasn't active before, or was active	844	before stop> (but only if the watcher wasn't active before, or was active
807	before, respectively. Note also that libev might stop watchers itself	845	before, respectively. Note also that libev might stop watchers itself
808	(e.g. non-repeating timers) in which case you have to C<ev_ref>	846	(e.g. non-repeating timers) in which case you have to C<ev_ref>
809	in the callback).	847	in the callback).
810		848
811	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	849	Example: Create a signal watcher, but keep it from keeping C<ev_run>
812	running when nothing else is active.	850	running when nothing else is active.
813		851
814	ev_signal exitsig;	852	ev_signal exitsig;
815	ev_signal_init (&exitsig, sig_cb, SIGINT);	853	ev_signal_init (&exitsig, sig_cb, SIGINT);
816	ev_signal_start (loop, &exitsig);	854	ev_signal_start (loop, &exitsig);
…		…
861	usually doesn't make much sense to set it to a lower value than C<0.01>,	899	usually doesn't make much sense to set it to a lower value than C<0.01>,
862	as this approaches the timing granularity of most systems. Note that if	900	as this approaches the timing granularity of most systems. Note that if
863	you do transactions with the outside world and you can't increase the	901	you do transactions with the outside world and you can't increase the
864	parallelity, then this setting will limit your transaction rate (if you	902	parallelity, then this setting will limit your transaction rate (if you
865	need to poll once per transaction and the I/O collect interval is 0.01,	903	need to poll once per transaction and the I/O collect interval is 0.01,
866	then you can't do more than 100 transations per second).	904	then you can't do more than 100 transactions per second).
867		905
868	Setting the I<timeout collect interval> can improve the opportunity for	906	Setting the I<timeout collect interval> can improve the opportunity for
869	saving power, as the program will "bundle" timer callback invocations that	907	saving power, as the program will "bundle" timer callback invocations that
870	are "near" in time together, by delaying some, thus reducing the number of	908	are "near" in time together, by delaying some, thus reducing the number of
871	times the process sleeps and wakes up again. Another useful technique to	909	times the process sleeps and wakes up again. Another useful technique to
…		…
879	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	917	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
880		918
881	=item ev_invoke_pending (loop)	919	=item ev_invoke_pending (loop)
882		920
883	This call will simply invoke all pending watchers while resetting their	921	This call will simply invoke all pending watchers while resetting their
884	pending state. Normally, C<ev_loop> does this automatically when required,	922	pending state. Normally, C<ev_run> does this automatically when required,
885	but when overriding the invoke callback this call comes handy.	923	but when overriding the invoke callback this call comes handy. This
		924	function can be invoked from a watcher - this can be useful for example
		925	when you want to do some lengthy calculation and want to pass further
		926	event handling to another thread (you still have to make sure only one
		927	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
886		928
887	=item int ev_pending_count (loop)	929	=item int ev_pending_count (loop)
888		930
889	Returns the number of pending watchers - zero indicates that no watchers	931	Returns the number of pending watchers - zero indicates that no watchers
890	are pending.	932	are pending.
891		933
892	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	934	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
893		935
894	This overrides the invoke pending functionality of the loop: Instead of	936	This overrides the invoke pending functionality of the loop: Instead of
895	invoking all pending watchers when there are any, C<ev_loop> will call	937	invoking all pending watchers when there are any, C<ev_run> will call
896	this callback instead. This is useful, for example, when you want to	938	this callback instead. This is useful, for example, when you want to
897	invoke the actual watchers inside another context (another thread etc.).	939	invoke the actual watchers inside another context (another thread etc.).
898		940
899	If you want to reset the callback, use C<ev_invoke_pending> as new	941	If you want to reset the callback, use C<ev_invoke_pending> as new
900	callback.	942	callback.
…		…
903		945
904	Sometimes you want to share the same loop between multiple threads. This	946	Sometimes you want to share the same loop between multiple threads. This
905	can be done relatively simply by putting mutex_lock/unlock calls around	947	can be done relatively simply by putting mutex_lock/unlock calls around
906	each call to a libev function.	948	each call to a libev function.
907		949
908	However, C<ev_loop> can run an indefinite time, so it is not feasible to	950	However, C<ev_run> can run an indefinite time, so it is not feasible
909	wait for it to return. One way around this is to wake up the loop via	951	to wait for it to return. One way around this is to wake up the event
910	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	952	loop via C<ev_break> and C<av_async_send>, another way is to set these
911	and I<acquire> callbacks on the loop.	953	I<release> and I<acquire> callbacks on the loop.
912		954
913	When set, then C<release> will be called just before the thread is	955	When set, then C<release> will be called just before the thread is
914	suspended waiting for new events, and C<acquire> is called just	956	suspended waiting for new events, and C<acquire> is called just
915	afterwards.	957	afterwards.
916		958
…		…
919		961
920	While event loop modifications are allowed between invocations of	962	While event loop modifications are allowed between invocations of
921	C<release> and C<acquire> (that's their only purpose after all), no	963	C<release> and C<acquire> (that's their only purpose after all), no
922	modifications done will affect the event loop, i.e. adding watchers will	964	modifications done will affect the event loop, i.e. adding watchers will
923	have no effect on the set of file descriptors being watched, or the time	965	have no effect on the set of file descriptors being watched, or the time
924	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	966	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
925	to take note of any changes you made.	967	to take note of any changes you made.
926		968
927	In theory, threads executing C<ev_loop> will be async-cancel safe between	969	In theory, threads executing C<ev_run> will be async-cancel safe between
928	invocations of C<release> and C<acquire>.	970	invocations of C<release> and C<acquire>.
929		971
930	See also the locking example in the C<THREADS> section later in this	972	See also the locking example in the C<THREADS> section later in this
931	document.	973	document.
932		974
…		…
941	These two functions can be used to associate arbitrary data with a loop,	983	These two functions can be used to associate arbitrary data with a loop,
942	and are intended solely for the C<invoke_pending_cb>, C<release> and	984	and are intended solely for the C<invoke_pending_cb>, C<release> and
943	C<acquire> callbacks described above, but of course can be (ab-)used for	985	C<acquire> callbacks described above, but of course can be (ab-)used for
944	any other purpose as well.	986	any other purpose as well.
945		987
946	=item ev_loop_verify (loop)	988	=item ev_verify (loop)
947		989
948	This function only does something when C<EV_VERIFY> support has been	990	This function only does something when C<EV_VERIFY> support has been
949	compiled in, which is the default for non-minimal builds. It tries to go	991	compiled in, which is the default for non-minimal builds. It tries to go
950	through all internal structures and checks them for validity. If anything	992	through all internal structures and checks them for validity. If anything
951	is found to be inconsistent, it will print an error message to standard	993	is found to be inconsistent, it will print an error message to standard
…		…
962		1004
963	In the following description, uppercase C<TYPE> in names stands for the	1005	In the following description, uppercase C<TYPE> in names stands for the
964	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1006	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
965	watchers and C<ev_io_start> for I/O watchers.	1007	watchers and C<ev_io_start> for I/O watchers.
966		1008
967	A watcher is a structure that you create and register to record your	1009	A watcher is an opaque structure that you allocate and register to record
968	interest in some event. For instance, if you want to wait for STDIN to	1010	your interest in some event. To make a concrete example, imagine you want
969	become readable, you would create an C<ev_io> watcher for that:	1011	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1012	for that:
970		1013
971	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1014	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
972	{	1015	{
973	ev_io_stop (w);	1016	ev_io_stop (w);
974	ev_unloop (loop, EVUNLOOP_ALL);	1017	ev_break (loop, EVBREAK_ALL);
975	}	1018	}
976		1019
977	struct ev_loop *loop = ev_default_loop (0);	1020	struct ev_loop *loop = ev_default_loop (0);
978		1021
979	ev_io stdin_watcher;	1022	ev_io stdin_watcher;
980		1023
981	ev_init (&stdin_watcher, my_cb);	1024	ev_init (&stdin_watcher, my_cb);
982	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1025	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
983	ev_io_start (loop, &stdin_watcher);	1026	ev_io_start (loop, &stdin_watcher);
984		1027
985	ev_loop (loop, 0);	1028	ev_run (loop, 0);
986		1029
987	As you can see, you are responsible for allocating the memory for your	1030	As you can see, you are responsible for allocating the memory for your
988	watcher structures (and it is I<usually> a bad idea to do this on the	1031	watcher structures (and it is I<usually> a bad idea to do this on the
989	stack).	1032	stack).
990		1033
991	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1034	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
992	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1035	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
993		1036
994	Each watcher structure must be initialised by a call to C<ev_init	1037	Each watcher structure must be initialised by a call to C<ev_init (watcher
995	(watcher *, callback)>, which expects a callback to be provided. This	1038	*, callback)>, which expects a callback to be provided. This callback is
996	callback gets invoked each time the event occurs (or, in the case of I/O	1039	invoked each time the event occurs (or, in the case of I/O watchers, each
997	watchers, each time the event loop detects that the file descriptor given	1040	time the event loop detects that the file descriptor given is readable
998	is readable and/or writable).	1041	and/or writable).
999		1042
1000	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1043	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1001	macro to configure it, with arguments specific to the watcher type. There	1044	macro to configure it, with arguments specific to the watcher type. There
1002	is also a macro to combine initialisation and setting in one call: C<<	1045	is also a macro to combine initialisation and setting in one call: C<<
1003	ev_TYPE_init (watcher *, callback, ...) >>.	1046	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1026	=item C<EV_WRITE>	1069	=item C<EV_WRITE>
1027		1070
1028	The file descriptor in the C<ev_io> watcher has become readable and/or	1071	The file descriptor in the C<ev_io> watcher has become readable and/or
1029	writable.	1072	writable.
1030		1073
1031	=item C<EV_TIMEOUT>	1074	=item C<EV_TIMER>
1032		1075
1033	The C<ev_timer> watcher has timed out.	1076	The C<ev_timer> watcher has timed out.
1034		1077
1035	=item C<EV_PERIODIC>	1078	=item C<EV_PERIODIC>
1036		1079
…		…
1054		1097
1055	=item C<EV_PREPARE>	1098	=item C<EV_PREPARE>
1056		1099
1057	=item C<EV_CHECK>	1100	=item C<EV_CHECK>
1058		1101
1059	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1102	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1060	to gather new events, and all C<ev_check> watchers are invoked just after	1103	to gather new events, and all C<ev_check> watchers are invoked just after
1061	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1104	C<ev_run> has gathered them, but before it invokes any callbacks for any
1062	received events. Callbacks of both watcher types can start and stop as	1105	received events. Callbacks of both watcher types can start and stop as
1063	many watchers as they want, and all of them will be taken into account	1106	many watchers as they want, and all of them will be taken into account
1064	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1107	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1065	C<ev_loop> from blocking).	1108	C<ev_run> from blocking).
1066		1109
1067	=item C<EV_EMBED>	1110	=item C<EV_EMBED>
1068		1111
1069	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1112	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1070		1113
…		…
1098	example it might indicate that a fd is readable or writable, and if your	1141	example it might indicate that a fd is readable or writable, and if your
1099	callbacks is well-written it can just attempt the operation and cope with	1142	callbacks is well-written it can just attempt the operation and cope with
1100	the error from read() or write(). This will not work in multi-threaded	1143	the error from read() or write(). This will not work in multi-threaded
1101	programs, though, as the fd could already be closed and reused for another	1144	programs, though, as the fd could already be closed and reused for another
1102	thing, so beware.	1145	thing, so beware.
		1146
		1147	=back
		1148
		1149	=head2 WATCHER STATES
		1150
		1151	There are various watcher states mentioned throughout this manual -
		1152	active, pending and so on. In this section these states and the rules to
		1153	transition between them will be described in more detail - and while these
		1154	rules might look complicated, they usually do "the right thing".
		1155
		1156	=over 4
		1157
		1158	=item initialiased
		1159
		1160	Before a watcher can be registered with the event looop it has to be
		1161	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1162	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1163
		1164	In this state it is simply some block of memory that is suitable for use
		1165	in an event loop. It can be moved around, freed, reused etc. at will.
		1166
		1167	=item started/running/active
		1168
		1169	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1170	property of the event loop, and is actively waiting for events. While in
		1171	this state it cannot be accessed (except in a few documented ways), moved,
		1172	freed or anything else - the only legal thing is to keep a pointer to it,
		1173	and call libev functions on it that are documented to work on active watchers.
		1174
		1175	=item pending
		1176
		1177	If a watcher is active and libev determines that an event it is interested
		1178	in has occurred (such as a timer expiring), it will become pending. It will
		1179	stay in this pending state until either it is stopped or its callback is
		1180	about to be invoked, so it is not normally pending inside the watcher
		1181	callback.
		1182
		1183	The watcher might or might not be active while it is pending (for example,
		1184	an expired non-repeating timer can be pending but no longer active). If it
		1185	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1186	but it is still property of the event loop at this time, so cannot be
		1187	moved, freed or reused. And if it is active the rules described in the
		1188	previous item still apply.
		1189
		1190	It is also possible to feed an event on a watcher that is not active (e.g.
		1191	via C<ev_feed_event>), in which case it becomes pending without being
		1192	active.
		1193
		1194	=item stopped
		1195
		1196	A watcher can be stopped implicitly by libev (in which case it might still
		1197	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1198	latter will clear any pending state the watcher might be in, regardless
		1199	of whether it was active or not, so stopping a watcher explicitly before
		1200	freeing it is often a good idea.
		1201
		1202	While stopped (and not pending) the watcher is essentially in the
		1203	initialised state, that is it can be reused, moved, modified in any way
		1204	you wish.
1103		1205
1104	=back	1206	=back
1105		1207
1106	=head2 GENERIC WATCHER FUNCTIONS	1208	=head2 GENERIC WATCHER FUNCTIONS
1107		1209
…		…
1369		1471
1370	For example, to emulate how many other event libraries handle priorities,	1472	For example, to emulate how many other event libraries handle priorities,
1371	you can associate an C<ev_idle> watcher to each such watcher, and in	1473	you can associate an C<ev_idle> watcher to each such watcher, and in
1372	the normal watcher callback, you just start the idle watcher. The real	1474	the normal watcher callback, you just start the idle watcher. The real
1373	processing is done in the idle watcher callback. This causes libev to	1475	processing is done in the idle watcher callback. This causes libev to
1374	continously poll and process kernel event data for the watcher, but when	1476	continuously poll and process kernel event data for the watcher, but when
1375	the lock-out case is known to be rare (which in turn is rare :), this is	1477	the lock-out case is known to be rare (which in turn is rare :), this is
1376	workable.	1478	workable.
1377		1479
1378	Usually, however, the lock-out model implemented that way will perform	1480	Usually, however, the lock-out model implemented that way will perform
1379	miserably under the type of load it was designed to handle. In that case,	1481	miserably under the type of load it was designed to handle. In that case,
…		…
1393	{	1495	{
1394	// stop the I/O watcher, we received the event, but	1496	// stop the I/O watcher, we received the event, but
1395	// are not yet ready to handle it.	1497	// are not yet ready to handle it.
1396	ev_io_stop (EV_A_ w);	1498	ev_io_stop (EV_A_ w);
1397		1499
1398	// start the idle watcher to ahndle the actual event.	1500	// start the idle watcher to handle the actual event.
1399	// it will not be executed as long as other watchers	1501	// it will not be executed as long as other watchers
1400	// with the default priority are receiving events.	1502	// with the default priority are receiving events.
1401	ev_idle_start (EV_A_ &idle);	1503	ev_idle_start (EV_A_ &idle);
1402	}	1504	}
1403		1505
…		…
1457		1559
1458	If you cannot use non-blocking mode, then force the use of a	1560	If you cannot use non-blocking mode, then force the use of a
1459	known-to-be-good backend (at the time of this writing, this includes only	1561	known-to-be-good backend (at the time of this writing, this includes only
1460	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1562	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1461	descriptors for which non-blocking operation makes no sense (such as	1563	descriptors for which non-blocking operation makes no sense (such as
1462	files) - libev doesn't guarentee any specific behaviour in that case.	1564	files) - libev doesn't guarantee any specific behaviour in that case.
1463		1565
1464	Another thing you have to watch out for is that it is quite easy to	1566	Another thing you have to watch out for is that it is quite easy to
1465	receive "spurious" readiness notifications, that is your callback might	1567	receive "spurious" readiness notifications, that is your callback might
1466	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1568	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1467	because there is no data. Not only are some backends known to create a	1569	because there is no data. Not only are some backends known to create a
…		…
1532		1634
1533	So when you encounter spurious, unexplained daemon exits, make sure you	1635	So when you encounter spurious, unexplained daemon exits, make sure you
1534	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1636	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1535	somewhere, as that would have given you a big clue).	1637	somewhere, as that would have given you a big clue).
1536		1638
		1639	=head3 The special problem of accept()ing when you can't
		1640
		1641	Many implementations of the POSIX C<accept> function (for example,
		1642	found in post-2004 Linux) have the peculiar behaviour of not removing a
		1643	connection from the pending queue in all error cases.
		1644
		1645	For example, larger servers often run out of file descriptors (because
		1646	of resource limits), causing C<accept> to fail with C<ENFILE> but not
		1647	rejecting the connection, leading to libev signalling readiness on
		1648	the next iteration again (the connection still exists after all), and
		1649	typically causing the program to loop at 100% CPU usage.
		1650
		1651	Unfortunately, the set of errors that cause this issue differs between
		1652	operating systems, there is usually little the app can do to remedy the
		1653	situation, and no known thread-safe method of removing the connection to
		1654	cope with overload is known (to me).
		1655
		1656	One of the easiest ways to handle this situation is to just ignore it
		1657	- when the program encounters an overload, it will just loop until the
		1658	situation is over. While this is a form of busy waiting, no OS offers an
		1659	event-based way to handle this situation, so it's the best one can do.
		1660
		1661	A better way to handle the situation is to log any errors other than
		1662	C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
		1663	messages, and continue as usual, which at least gives the user an idea of
		1664	what could be wrong ("raise the ulimit!"). For extra points one could stop
		1665	the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
		1666	usage.
		1667
		1668	If your program is single-threaded, then you could also keep a dummy file
		1669	descriptor for overload situations (e.g. by opening F</dev/null>), and
		1670	when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
		1671	close that fd, and create a new dummy fd. This will gracefully refuse
		1672	clients under typical overload conditions.
		1673
		1674	The last way to handle it is to simply log the error and C<exit>, as
		1675	is often done with C<malloc> failures, but this results in an easy
		1676	opportunity for a DoS attack.
1537		1677
1538	=head3 Watcher-Specific Functions	1678	=head3 Watcher-Specific Functions
1539		1679
1540	=over 4	1680	=over 4
1541		1681
…		…
1573	...	1713	...
1574	struct ev_loop *loop = ev_default_init (0);	1714	struct ev_loop *loop = ev_default_init (0);
1575	ev_io stdin_readable;	1715	ev_io stdin_readable;
1576	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1716	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1577	ev_io_start (loop, &stdin_readable);	1717	ev_io_start (loop, &stdin_readable);
1578	ev_loop (loop, 0);	1718	ev_run (loop, 0);
1579		1719
1580		1720
1581	=head2 C<ev_timer> - relative and optionally repeating timeouts	1721	=head2 C<ev_timer> - relative and optionally repeating timeouts
1582		1722
1583	Timer watchers are simple relative timers that generate an event after a	1723	Timer watchers are simple relative timers that generate an event after a
…		…
1592	The callback is guaranteed to be invoked only I<after> its timeout has	1732	The callback is guaranteed to be invoked only I<after> its timeout has
1593	passed (not I<at>, so on systems with very low-resolution clocks this	1733	passed (not I<at>, so on systems with very low-resolution clocks this
1594	might introduce a small delay). If multiple timers become ready during the	1734	might introduce a small delay). If multiple timers become ready during the
1595	same loop iteration then the ones with earlier time-out values are invoked	1735	same loop iteration then the ones with earlier time-out values are invoked
1596	before ones of the same priority with later time-out values (but this is	1736	before ones of the same priority with later time-out values (but this is
1597	no longer true when a callback calls C<ev_loop> recursively).	1737	no longer true when a callback calls C<ev_run> recursively).
1598		1738
1599	=head3 Be smart about timeouts	1739	=head3 Be smart about timeouts
1600		1740
1601	Many real-world problems involve some kind of timeout, usually for error	1741	Many real-world problems involve some kind of timeout, usually for error
1602	recovery. A typical example is an HTTP request - if the other side hangs,	1742	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1688	ev_tstamp timeout = last_activity + 60.;	1828	ev_tstamp timeout = last_activity + 60.;
1689		1829
1690	// if last_activity + 60. is older than now, we did time out	1830	// if last_activity + 60. is older than now, we did time out
1691	if (timeout < now)	1831	if (timeout < now)
1692	{	1832	{
1693	// timeout occured, take action	1833	// timeout occurred, take action
1694	}	1834	}
1695	else	1835	else
1696	{	1836	{
1697	// callback was invoked, but there was some activity, re-arm	1837	// callback was invoked, but there was some activity, re-arm
1698	// the watcher to fire in last_activity + 60, which is	1838	// the watcher to fire in last_activity + 60, which is
…		…
1720	to the current time (meaning we just have some activity :), then call the	1860	to the current time (meaning we just have some activity :), then call the
1721	callback, which will "do the right thing" and start the timer:	1861	callback, which will "do the right thing" and start the timer:
1722		1862
1723	ev_init (timer, callback);	1863	ev_init (timer, callback);
1724	last_activity = ev_now (loop);	1864	last_activity = ev_now (loop);
1725	callback (loop, timer, EV_TIMEOUT);	1865	callback (loop, timer, EV_TIMER);
1726		1866
1727	And when there is some activity, simply store the current time in	1867	And when there is some activity, simply store the current time in
1728	C<last_activity>, no libev calls at all:	1868	C<last_activity>, no libev calls at all:
1729		1869
1730	last_actiivty = ev_now (loop);	1870	last_activity = ev_now (loop);
1731		1871
1732	This technique is slightly more complex, but in most cases where the	1872	This technique is slightly more complex, but in most cases where the
1733	time-out is unlikely to be triggered, much more efficient.	1873	time-out is unlikely to be triggered, much more efficient.
1734		1874
1735	Changing the timeout is trivial as well (if it isn't hard-coded in the	1875	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1773		1913
1774	=head3 The special problem of time updates	1914	=head3 The special problem of time updates
1775		1915
1776	Establishing the current time is a costly operation (it usually takes at	1916	Establishing the current time is a costly operation (it usually takes at
1777	least two system calls): EV therefore updates its idea of the current	1917	least two system calls): EV therefore updates its idea of the current
1778	time only before and after C<ev_loop> collects new events, which causes a	1918	time only before and after C<ev_run> collects new events, which causes a
1779	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1919	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1780	lots of events in one iteration.	1920	lots of events in one iteration.
1781		1921
1782	The relative timeouts are calculated relative to the C<ev_now ()>	1922	The relative timeouts are calculated relative to the C<ev_now ()>
1783	time. This is usually the right thing as this timestamp refers to the time	1923	time. This is usually the right thing as this timestamp refers to the time
…		…
1861	Returns the remaining time until a timer fires. If the timer is active,	2001	Returns the remaining time until a timer fires. If the timer is active,
1862	then this time is relative to the current event loop time, otherwise it's	2002	then this time is relative to the current event loop time, otherwise it's
1863	the timeout value currently configured.	2003	the timeout value currently configured.
1864		2004
1865	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns	2005	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
1866	C<5>. When the timer is started and one second passes, C<ev_timer_remain>	2006	C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
1867	will return C<4>. When the timer expires and is restarted, it will return	2007	will return C<4>. When the timer expires and is restarted, it will return
1868	roughly C<7> (likely slightly less as callback invocation takes some time,	2008	roughly C<7> (likely slightly less as callback invocation takes some time,
1869	too), and so on.	2009	too), and so on.
1870		2010
1871	=item ev_tstamp repeat [read-write]	2011	=item ev_tstamp repeat [read-write]
…		…
1900	}	2040	}
1901		2041
1902	ev_timer mytimer;	2042	ev_timer mytimer;
1903	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2043	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1904	ev_timer_again (&mytimer); /* start timer */	2044	ev_timer_again (&mytimer); /* start timer */
1905	ev_loop (loop, 0);	2045	ev_run (loop, 0);
1906		2046
1907	// and in some piece of code that gets executed on any "activity":	2047	// and in some piece of code that gets executed on any "activity":
1908	// reset the timeout to start ticking again at 10 seconds	2048	// reset the timeout to start ticking again at 10 seconds
1909	ev_timer_again (&mytimer);	2049	ev_timer_again (&mytimer);
1910		2050
…		…
1936		2076
1937	As with timers, the callback is guaranteed to be invoked only when the	2077	As with timers, the callback is guaranteed to be invoked only when the
1938	point in time where it is supposed to trigger has passed. If multiple	2078	point in time where it is supposed to trigger has passed. If multiple
1939	timers become ready during the same loop iteration then the ones with	2079	timers become ready during the same loop iteration then the ones with
1940	earlier time-out values are invoked before ones with later time-out values	2080	earlier time-out values are invoked before ones with later time-out values
1941	(but this is no longer true when a callback calls C<ev_loop> recursively).	2081	(but this is no longer true when a callback calls C<ev_run> recursively).
1942		2082
1943	=head3 Watcher-Specific Functions and Data Members	2083	=head3 Watcher-Specific Functions and Data Members
1944		2084
1945	=over 4	2085	=over 4
1946		2086
…		…
2074	Example: Call a callback every hour, or, more precisely, whenever the	2214	Example: Call a callback every hour, or, more precisely, whenever the
2075	system time is divisible by 3600. The callback invocation times have	2215	system time is divisible by 3600. The callback invocation times have
2076	potentially a lot of jitter, but good long-term stability.	2216	potentially a lot of jitter, but good long-term stability.
2077		2217
2078	static void	2218	static void
2079	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2219	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
2080	{	2220	{
2081	... its now a full hour (UTC, or TAI or whatever your clock follows)	2221	... its now a full hour (UTC, or TAI or whatever your clock follows)
2082	}	2222	}
2083		2223
2084	ev_periodic hourly_tick;	2224	ev_periodic hourly_tick;
…		…
2131	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should	2271	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
2132	not be unduly interrupted. If you have a problem with system calls getting	2272	not be unduly interrupted. If you have a problem with system calls getting
2133	interrupted by signals you can block all signals in an C<ev_check> watcher	2273	interrupted by signals you can block all signals in an C<ev_check> watcher
2134	and unblock them in an C<ev_prepare> watcher.	2274	and unblock them in an C<ev_prepare> watcher.
2135		2275
2136	=head3 The special problem of inheritance over execve	2276	=head3 The special problem of inheritance over fork/execve/pthread_create
2137		2277
2138	Both the signal mask (C<sigprocmask>) and the signal disposition	2278	Both the signal mask (C<sigprocmask>) and the signal disposition
2139	(C<sigaction>) are unspecified after starting a signal watcher (and after	2279	(C<sigaction>) are unspecified after starting a signal watcher (and after
2140	stopping it again), that is, libev might or might not block the signal,	2280	stopping it again), that is, libev might or might not block the signal,
2141	and might or might not set or restore the installed signal handler.	2281	and might or might not set or restore the installed signal handler.
…		…
2151		2291
2152	The simplest way to ensure that the signal mask is reset in the child is	2292	The simplest way to ensure that the signal mask is reset in the child is
2153	to install a fork handler with C<pthread_atfork> that resets it. That will	2293	to install a fork handler with C<pthread_atfork> that resets it. That will
2154	catch fork calls done by libraries (such as the libc) as well.	2294	catch fork calls done by libraries (such as the libc) as well.
2155		2295
2156	In current versions of libev, you can also ensure that the signal mask is	2296	In current versions of libev, the signal will not be blocked indefinitely
2157	not blocking any signals (except temporarily, so thread users watch out)	2297	unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
2158	by specifying the C<EVFLAG_NOSIGFD> when creating the event loop. This	2298	the window of opportunity for problems, it will not go away, as libev
2159	is not guaranteed for future versions, however.	2299	I<has> to modify the signal mask, at least temporarily.
		2300
		2301	So I can't stress this enough: I<If you do not reset your signal mask when
		2302	you expect it to be empty, you have a race condition in your code>. This
		2303	is not a libev-specific thing, this is true for most event libraries.
2160		2304
2161	=head3 Watcher-Specific Functions and Data Members	2305	=head3 Watcher-Specific Functions and Data Members
2162		2306
2163	=over 4	2307	=over 4
2164		2308
…		…
2180	Example: Try to exit cleanly on SIGINT.	2324	Example: Try to exit cleanly on SIGINT.
2181		2325
2182	static void	2326	static void
2183	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2327	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2184	{	2328	{
2185	ev_unloop (loop, EVUNLOOP_ALL);	2329	ev_break (loop, EVBREAK_ALL);
2186	}	2330	}
2187		2331
2188	ev_signal signal_watcher;	2332	ev_signal signal_watcher;
2189	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2333	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2190	ev_signal_start (loop, &signal_watcher);	2334	ev_signal_start (loop, &signal_watcher);
…		…
2576		2720
2577	Prepare and check watchers are usually (but not always) used in pairs:	2721	Prepare and check watchers are usually (but not always) used in pairs:
2578	prepare watchers get invoked before the process blocks and check watchers	2722	prepare watchers get invoked before the process blocks and check watchers
2579	afterwards.	2723	afterwards.
2580		2724
2581	You I<must not> call C<ev_loop> or similar functions that enter	2725	You I<must not> call C<ev_run> or similar functions that enter
2582	the current event loop from either C<ev_prepare> or C<ev_check>	2726	the current event loop from either C<ev_prepare> or C<ev_check>
2583	watchers. Other loops than the current one are fine, however. The	2727	watchers. Other loops than the current one are fine, however. The
2584	rationale behind this is that you do not need to check for recursion in	2728	rationale behind this is that you do not need to check for recursion in
2585	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2729	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2586	C<ev_check> so if you have one watcher of each kind they will always be	2730	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2754		2898
2755	if (timeout >= 0)	2899	if (timeout >= 0)
2756	// create/start timer	2900	// create/start timer
2757		2901
2758	// poll	2902	// poll
2759	ev_loop (EV_A_ 0);	2903	ev_run (EV_A_ 0);
2760		2904
2761	// stop timer again	2905	// stop timer again
2762	if (timeout >= 0)	2906	if (timeout >= 0)
2763	ev_timer_stop (EV_A_ &to);	2907	ev_timer_stop (EV_A_ &to);
2764		2908
…		…
2842	if you do not want that, you need to temporarily stop the embed watcher).	2986	if you do not want that, you need to temporarily stop the embed watcher).
2843		2987
2844	=item ev_embed_sweep (loop, ev_embed *)	2988	=item ev_embed_sweep (loop, ev_embed *)
2845		2989
2846	Make a single, non-blocking sweep over the embedded loop. This works	2990	Make a single, non-blocking sweep over the embedded loop. This works
2847	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2991	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2848	appropriate way for embedded loops.	2992	appropriate way for embedded loops.
2849		2993
2850	=item struct ev_loop *other [read-only]	2994	=item struct ev_loop *other [read-only]
2851		2995
2852	The embedded event loop.	2996	The embedded event loop.
…		…
2912	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3056	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2913	handlers will be invoked, too, of course.	3057	handlers will be invoked, too, of course.
2914		3058
2915	=head3 The special problem of life after fork - how is it possible?	3059	=head3 The special problem of life after fork - how is it possible?
2916		3060
2917	Most uses of C<fork()> consist of forking, then some simple calls to ste	3061	Most uses of C<fork()> consist of forking, then some simple calls to set
2918	up/change the process environment, followed by a call to C<exec()>. This	3062	up/change the process environment, followed by a call to C<exec()>. This
2919	sequence should be handled by libev without any problems.	3063	sequence should be handled by libev without any problems.
2920		3064
2921	This changes when the application actually wants to do event handling	3065	This changes when the application actually wants to do event handling
2922	in the child, or both parent in child, in effect "continuing" after the	3066	in the child, or both parent in child, in effect "continuing" after the
…		…
2938	disadvantage of having to use multiple event loops (which do not support	3082	disadvantage of having to use multiple event loops (which do not support
2939	signal watchers).	3083	signal watchers).
2940		3084
2941	When this is not possible, or you want to use the default loop for	3085	When this is not possible, or you want to use the default loop for
2942	other reasons, then in the process that wants to start "fresh", call	3086	other reasons, then in the process that wants to start "fresh", call
2943	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3087	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2944	the default loop will "orphan" (not stop) all registered watchers, so you	3088	Destroying the default loop will "orphan" (not stop) all registered
2945	have to be careful not to execute code that modifies those watchers. Note	3089	watchers, so you have to be careful not to execute code that modifies
2946	also that in that case, you have to re-register any signal watchers.	3090	those watchers. Note also that in that case, you have to re-register any
		3091	signal watchers.
2947		3092
2948	=head3 Watcher-Specific Functions and Data Members	3093	=head3 Watcher-Specific Functions and Data Members
2949		3094
2950	=over 4	3095	=over 4
2951		3096
…		…
2956	believe me.	3101	believe me.
2957		3102
2958	=back	3103	=back
2959		3104
2960		3105
2961	=head2 C<ev_async> - how to wake up another event loop	3106	=head2 C<ev_async> - how to wake up an event loop
2962		3107
2963	In general, you cannot use an C<ev_loop> from multiple threads or other	3108	In general, you cannot use an C<ev_run> from multiple threads or other
2964	asynchronous sources such as signal handlers (as opposed to multiple event	3109	asynchronous sources such as signal handlers (as opposed to multiple event
2965	loops - those are of course safe to use in different threads).	3110	loops - those are of course safe to use in different threads).
2966		3111
2967	Sometimes, however, you need to wake up another event loop you do not	3112	Sometimes, however, you need to wake up an event loop you do not control,
2968	control, for example because it belongs to another thread. This is what	3113	for example because it belongs to another thread. This is what C<ev_async>
2969	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3114	watchers do: as long as the C<ev_async> watcher is active, you can signal
2970	can signal it by calling C<ev_async_send>, which is thread- and signal	3115	it by calling C<ev_async_send>, which is thread- and signal safe.
2971	safe.
2972		3116
2973	This functionality is very similar to C<ev_signal> watchers, as signals,	3117	This functionality is very similar to C<ev_signal> watchers, as signals,
2974	too, are asynchronous in nature, and signals, too, will be compressed	3118	too, are asynchronous in nature, and signals, too, will be compressed
2975	(i.e. the number of callback invocations may be less than the number of	3119	(i.e. the number of callback invocations may be less than the number of
2976	C<ev_async_sent> calls).	3120	C<ev_async_sent> calls).
…		…
3131		3275
3132	If C<timeout> is less than 0, then no timeout watcher will be	3276	If C<timeout> is less than 0, then no timeout watcher will be
3133	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3277	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
3134	repeat = 0) will be started. C<0> is a valid timeout.	3278	repeat = 0) will be started. C<0> is a valid timeout.
3135		3279
3136	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	3280	The callback has the type C<void (*cb)(int revents, void *arg)> and is
3137	passed an C<revents> set like normal event callbacks (a combination of	3281	passed an C<revents> set like normal event callbacks (a combination of
3138	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3282	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
3139	value passed to C<ev_once>. Note that it is possible to receive I<both>	3283	value passed to C<ev_once>. Note that it is possible to receive I<both>
3140	a timeout and an io event at the same time - you probably should give io	3284	a timeout and an io event at the same time - you probably should give io
3141	events precedence.	3285	events precedence.
3142		3286
3143	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3287	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
3144		3288
3145	static void stdin_ready (int revents, void *arg)	3289	static void stdin_ready (int revents, void *arg)
3146	{	3290	{
3147	if (revents & EV_READ)	3291	if (revents & EV_READ)
3148	/* stdin might have data for us, joy! */;	3292	/* stdin might have data for us, joy! */;
3149	else if (revents & EV_TIMEOUT)	3293	else if (revents & EV_TIMER)
3150	/* doh, nothing entered */;	3294	/* doh, nothing entered */;
3151	}	3295	}
3152		3296
3153	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3297	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3154		3298
…		…
3288	myclass obj;	3432	myclass obj;
3289	ev::io iow;	3433	ev::io iow;
3290	iow.set <myclass, &myclass::io_cb> (&obj);	3434	iow.set <myclass, &myclass::io_cb> (&obj);
3291		3435
3292	=item w->set (object *)	3436	=item w->set (object *)
3293
3294	This is an B<experimental> feature that might go away in a future version.
3295		3437
3296	This is a variation of a method callback - leaving out the method to call	3438	This is a variation of a method callback - leaving out the method to call
3297	will default the method to C<operator ()>, which makes it possible to use	3439	will default the method to C<operator ()>, which makes it possible to use
3298	functor objects without having to manually specify the C<operator ()> all	3440	functor objects without having to manually specify the C<operator ()> all
3299	the time. Incidentally, you can then also leave out the template argument	3441	the time. Incidentally, you can then also leave out the template argument
…		…
3339	Associates a different C<struct ev_loop> with this watcher. You can only	3481	Associates a different C<struct ev_loop> with this watcher. You can only
3340	do this when the watcher is inactive (and not pending either).	3482	do this when the watcher is inactive (and not pending either).
3341		3483
3342	=item w->set ([arguments])	3484	=item w->set ([arguments])
3343		3485
3344	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3486	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3345	called at least once. Unlike the C counterpart, an active watcher gets	3487	method or a suitable start method must be called at least once. Unlike the
3346	automatically stopped and restarted when reconfiguring it with this	3488	C counterpart, an active watcher gets automatically stopped and restarted
3347	method.	3489	when reconfiguring it with this method.
3348		3490
3349	=item w->start ()	3491	=item w->start ()
3350		3492
3351	Starts the watcher. Note that there is no C<loop> argument, as the	3493	Starts the watcher. Note that there is no C<loop> argument, as the
3352	constructor already stores the event loop.	3494	constructor already stores the event loop.
3353		3495
		3496	=item w->start ([arguments])
		3497
		3498	Instead of calling C<set> and C<start> methods separately, it is often
		3499	convenient to wrap them in one call. Uses the same type of arguments as
		3500	the configure C<set> method of the watcher.
		3501
3354	=item w->stop ()	3502	=item w->stop ()
3355		3503
3356	Stops the watcher if it is active. Again, no C<loop> argument.	3504	Stops the watcher if it is active. Again, no C<loop> argument.
3357		3505
3358	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3506	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3370		3518
3371	=back	3519	=back
3372		3520
3373	=back	3521	=back
3374		3522
3375	Example: Define a class with an IO and idle watcher, start one of them in	3523	Example: Define a class with two I/O and idle watchers, start the I/O
3376	the constructor.	3524	watchers in the constructor.
3377		3525
3378	class myclass	3526	class myclass
3379	{	3527	{
3380	ev::io io ; void io_cb (ev::io &w, int revents);	3528	ev::io io ; void io_cb (ev::io &w, int revents);
		3529	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3381	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3530	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3382		3531
3383	myclass (int fd)	3532	myclass (int fd)
3384	{	3533	{
3385	io .set <myclass, &myclass::io_cb > (this);	3534	io .set <myclass, &myclass::io_cb > (this);
		3535	io2 .set <myclass, &myclass::io2_cb > (this);
3386	idle.set <myclass, &myclass::idle_cb> (this);	3536	idle.set <myclass, &myclass::idle_cb> (this);
3387		3537
3388	io.start (fd, ev::READ);	3538	io.set (fd, ev::WRITE); // configure the watcher
		3539	io.start (); // start it whenever convenient
		3540
		3541	io2.start (fd, ev::READ); // set + start in one call
3389	}	3542	}
3390	};	3543	};
3391		3544
3392		3545
3393	=head1 OTHER LANGUAGE BINDINGS	3546	=head1 OTHER LANGUAGE BINDINGS
…		…
3441	Erkki Seppala has written Ocaml bindings for libev, to be found at	3594	Erkki Seppala has written Ocaml bindings for libev, to be found at
3442	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.	3595	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
3443		3596
3444	=item Lua	3597	=item Lua
3445		3598
3446	Brian Maher has written a partial interface to libev	3599	Brian Maher has written a partial interface to libev for lua (at the
3447	for lua (only C<ev_io> and C<ev_timer>), to be found at	3600	time of this writing, only C<ev_io> and C<ev_timer>), to be found at
3448	L<http://github.com/brimworks/lua-ev>.	3601	L<http://github.com/brimworks/lua-ev>.
3449		3602
3450	=back	3603	=back
3451		3604
3452		3605
…		…
3467	loop argument"). The C<EV_A> form is used when this is the sole argument,	3620	loop argument"). The C<EV_A> form is used when this is the sole argument,
3468	C<EV_A_> is used when other arguments are following. Example:	3621	C<EV_A_> is used when other arguments are following. Example:
3469		3622
3470	ev_unref (EV_A);	3623	ev_unref (EV_A);
3471	ev_timer_add (EV_A_ watcher);	3624	ev_timer_add (EV_A_ watcher);
3472	ev_loop (EV_A_ 0);	3625	ev_run (EV_A_ 0);
3473		3626
3474	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3627	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3475	which is often provided by the following macro.	3628	which is often provided by the following macro.
3476		3629
3477	=item C<EV_P>, C<EV_P_>	3630	=item C<EV_P>, C<EV_P_>
…		…
3517	}	3670	}
3518		3671
3519	ev_check check;	3672	ev_check check;
3520	ev_check_init (&check, check_cb);	3673	ev_check_init (&check, check_cb);
3521	ev_check_start (EV_DEFAULT_ &check);	3674	ev_check_start (EV_DEFAULT_ &check);
3522	ev_loop (EV_DEFAULT_ 0);	3675	ev_run (EV_DEFAULT_ 0);
3523		3676
3524	=head1 EMBEDDING	3677	=head1 EMBEDDING
3525		3678
3526	Libev can (and often is) directly embedded into host	3679	Libev can (and often is) directly embedded into host
3527	applications. Examples of applications that embed it include the Deliantra	3680	applications. Examples of applications that embed it include the Deliantra
…		…
3607	libev.m4	3760	libev.m4
3608		3761
3609	=head2 PREPROCESSOR SYMBOLS/MACROS	3762	=head2 PREPROCESSOR SYMBOLS/MACROS
3610		3763
3611	Libev can be configured via a variety of preprocessor symbols you have to	3764	Libev can be configured via a variety of preprocessor symbols you have to
3612	define before including any of its files. The default in the absence of	3765	define before including (or compiling) any of its files. The default in
3613	autoconf is documented for every option.	3766	the absence of autoconf is documented for every option.
		3767
		3768	Symbols marked with "(h)" do not change the ABI, and can have different
		3769	values when compiling libev vs. including F<ev.h>, so it is permissible
		3770	to redefine them before including F<ev.h> without breaking compatibility
		3771	to a compiled library. All other symbols change the ABI, which means all
		3772	users of libev and the libev code itself must be compiled with compatible
		3773	settings.
3614		3774
3615	=over 4	3775	=over 4
3616		3776
		3777	=item EV_COMPAT3 (h)
		3778
		3779	Backwards compatibility is a major concern for libev. This is why this
		3780	release of libev comes with wrappers for the functions and symbols that
		3781	have been renamed between libev version 3 and 4.
		3782
		3783	You can disable these wrappers (to test compatibility with future
		3784	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3785	sources. This has the additional advantage that you can drop the C<struct>
		3786	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3787	typedef in that case.
		3788
		3789	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3790	and in some even more future version the compatibility code will be
		3791	removed completely.
		3792
3617	=item EV_STANDALONE	3793	=item EV_STANDALONE (h)
3618		3794
3619	Must always be C<1> if you do not use autoconf configuration, which	3795	Must always be C<1> if you do not use autoconf configuration, which
3620	keeps libev from including F<config.h>, and it also defines dummy	3796	keeps libev from including F<config.h>, and it also defines dummy
3621	implementations for some libevent functions (such as logging, which is not	3797	implementations for some libevent functions (such as logging, which is not
3622	supported). It will also not define any of the structs usually found in	3798	supported). It will also not define any of the structs usually found in
…		…
3772	as well as for signal and thread safety in C<ev_async> watchers.	3948	as well as for signal and thread safety in C<ev_async> watchers.
3773		3949
3774	In the absence of this define, libev will use C<sig_atomic_t volatile>	3950	In the absence of this define, libev will use C<sig_atomic_t volatile>
3775	(from F<signal.h>), which is usually good enough on most platforms.	3951	(from F<signal.h>), which is usually good enough on most platforms.
3776		3952
3777	=item EV_H	3953	=item EV_H (h)
3778		3954
3779	The name of the F<ev.h> header file used to include it. The default if	3955	The name of the F<ev.h> header file used to include it. The default if
3780	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be	3956	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
3781	used to virtually rename the F<ev.h> header file in case of conflicts.	3957	used to virtually rename the F<ev.h> header file in case of conflicts.
3782		3958
3783	=item EV_CONFIG_H	3959	=item EV_CONFIG_H (h)
3784		3960
3785	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	3961	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
3786	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	3962	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
3787	C<EV_H>, above.	3963	C<EV_H>, above.
3788		3964
3789	=item EV_EVENT_H	3965	=item EV_EVENT_H (h)
3790		3966
3791	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	3967	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
3792	of how the F<event.h> header can be found, the default is C<"event.h">.	3968	of how the F<event.h> header can be found, the default is C<"event.h">.
3793		3969
3794	=item EV_PROTOTYPES	3970	=item EV_PROTOTYPES (h)
3795		3971
3796	If defined to be C<0>, then F<ev.h> will not define any function	3972	If defined to be C<0>, then F<ev.h> will not define any function
3797	prototypes, but still define all the structs and other symbols. This is	3973	prototypes, but still define all the structs and other symbols. This is
3798	occasionally useful if you want to provide your own wrapper functions	3974	occasionally useful if you want to provide your own wrapper functions
3799	around libev functions.	3975	around libev functions.
…		…
3821	fine.	3997	fine.
3822		3998
3823	If your embedding application does not need any priorities, defining these	3999	If your embedding application does not need any priorities, defining these
3824	both to C<0> will save some memory and CPU.	4000	both to C<0> will save some memory and CPU.
3825		4001
3826	=item EV_PERIODIC_ENABLE	4002	=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
		4003	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
		4004	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3827		4005
3828	If undefined or defined to be C<1>, then periodic timers are supported. If	4006	If undefined or defined to be C<1> (and the platform supports it), then
3829	defined to be C<0>, then they are not. Disabling them saves a few kB of	4007	the respective watcher type is supported. If defined to be C<0>, then it
3830	code.	4008	is not. Disabling watcher types mainly saves code size.
3831		4009
3832	=item EV_IDLE_ENABLE	4010	=item EV_FEATURES
3833
3834	If undefined or defined to be C<1>, then idle watchers are supported. If
3835	defined to be C<0>, then they are not. Disabling them saves a few kB of
3836	code.
3837
3838	=item EV_EMBED_ENABLE
3839
3840	If undefined or defined to be C<1>, then embed watchers are supported. If
3841	defined to be C<0>, then they are not. Embed watchers rely on most other
3842	watcher types, which therefore must not be disabled.
3843
3844	=item EV_STAT_ENABLE
3845
3846	If undefined or defined to be C<1>, then stat watchers are supported. If
3847	defined to be C<0>, then they are not.
3848
3849	=item EV_FORK_ENABLE
3850
3851	If undefined or defined to be C<1>, then fork watchers are supported. If
3852	defined to be C<0>, then they are not.
3853
3854	=item EV_ASYNC_ENABLE
3855
3856	If undefined or defined to be C<1>, then async watchers are supported. If
3857	defined to be C<0>, then they are not.
3858
3859	=item EV_MINIMAL
3860		4011
3861	If you need to shave off some kilobytes of code at the expense of some	4012	If you need to shave off some kilobytes of code at the expense of some
3862	speed (but with the full API), define this symbol to C<1>. Currently this	4013	speed (but with the full API), you can define this symbol to request
3863	is used to override some inlining decisions, saves roughly 30% code size	4014	certain subsets of functionality. The default is to enable all features
3864	on amd64. It also selects a much smaller 2-heap for timer management over	4015	that can be enabled on the platform.
3865	the default 4-heap.
3866		4016
3867	You can save even more by disabling watcher types you do not need	4017	A typical way to use this symbol is to define it to C<0> (or to a bitset
3868	and setting C<EV_MAXPRI> == C<EV_MINPRI>. Also, disabling C<assert>	4018	with some broad features you want) and then selectively re-enable
3869	(C<-DNDEBUG>) will usually reduce code size a lot.	4019	additional parts you want, for example if you want everything minimal,
		4020	but multiple event loop support, async and child watchers and the poll
		4021	backend, use this:
3870		4022
3871	Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to	4023	#define EV_FEATURES 0
3872	provide a bare-bones event library. See C<ev.h> for details on what parts	4024	#define EV_MULTIPLICITY 1
3873	of the API are still available, and do not complain if this subset changes	4025	#define EV_USE_POLL 1
3874	over time.	4026	#define EV_CHILD_ENABLE 1
		4027	#define EV_ASYNC_ENABLE 1
		4028
		4029	The actual value is a bitset, it can be a combination of the following
		4030	values:
		4031
		4032	=over 4
		4033
		4034	=item C<1> - faster/larger code
		4035
		4036	Use larger code to speed up some operations.
		4037
		4038	Currently this is used to override some inlining decisions (enlarging the
		4039	code size by roughly 30% on amd64).
		4040
		4041	When optimising for size, use of compiler flags such as C<-Os> with
		4042	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
		4043	assertions.
		4044
		4045	=item C<2> - faster/larger data structures
		4046
		4047	Replaces the small 2-heap for timer management by a faster 4-heap, larger
		4048	hash table sizes and so on. This will usually further increase code size
		4049	and can additionally have an effect on the size of data structures at
		4050	runtime.
		4051
		4052	=item C<4> - full API configuration
		4053
		4054	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
		4055	enables multiplicity (C<EV_MULTIPLICITY>=1).
		4056
		4057	=item C<8> - full API
		4058
		4059	This enables a lot of the "lesser used" API functions. See C<ev.h> for
		4060	details on which parts of the API are still available without this
		4061	feature, and do not complain if this subset changes over time.
		4062
		4063	=item C<16> - enable all optional watcher types
		4064
		4065	Enables all optional watcher types. If you want to selectively enable
		4066	only some watcher types other than I/O and timers (e.g. prepare,
		4067	embed, async, child...) you can enable them manually by defining
		4068	C<EV_watchertype_ENABLE> to C<1> instead.
		4069
		4070	=item C<32> - enable all backends
		4071
		4072	This enables all backends - without this feature, you need to enable at
		4073	least one backend manually (C<EV_USE_SELECT> is a good choice).
		4074
		4075	=item C<64> - enable OS-specific "helper" APIs
		4076
		4077	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
		4078	default.
		4079
		4080	=back
		4081
		4082	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
		4083	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
		4084	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
		4085	watchers, timers and monotonic clock support.
		4086
		4087	With an intelligent-enough linker (gcc+binutils are intelligent enough
		4088	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
		4089	your program might be left out as well - a binary starting a timer and an
		4090	I/O watcher then might come out at only 5Kb.
		4091
		4092	=item EV_AVOID_STDIO
		4093
		4094	If this is set to C<1> at compiletime, then libev will avoid using stdio
		4095	functions (printf, scanf, perror etc.). This will increase the code size
		4096	somewhat, but if your program doesn't otherwise depend on stdio and your
		4097	libc allows it, this avoids linking in the stdio library which is quite
		4098	big.
		4099
		4100	Note that error messages might become less precise when this option is
		4101	enabled.
3875		4102
3876	=item EV_NSIG	4103	=item EV_NSIG
3877		4104
3878	The highest supported signal number, +1 (or, the number of	4105	The highest supported signal number, +1 (or, the number of
3879	signals): Normally, libev tries to deduce the maximum number of signals	4106	signals): Normally, libev tries to deduce the maximum number of signals
3880	automatically, but sometimes this fails, in which case it can be	4107	automatically, but sometimes this fails, in which case it can be
3881	specified. Also, using a lower number than detected (C<32> should be	4108	specified. Also, using a lower number than detected (C<32> should be
3882	good for about any system in existance) can save some memory, as libev	4109	good for about any system in existence) can save some memory, as libev
3883	statically allocates some 12-24 bytes per signal number.	4110	statically allocates some 12-24 bytes per signal number.
3884		4111
3885	=item EV_PID_HASHSIZE	4112	=item EV_PID_HASHSIZE
3886		4113
3887	C<ev_child> watchers use a small hash table to distribute workload by	4114	C<ev_child> watchers use a small hash table to distribute workload by
3888	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	4115	pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
3889	than enough. If you need to manage thousands of children you might want to	4116	usually more than enough. If you need to manage thousands of children you
3890	increase this value (I<must> be a power of two).	4117	might want to increase this value (I<must> be a power of two).
3891		4118
3892	=item EV_INOTIFY_HASHSIZE	4119	=item EV_INOTIFY_HASHSIZE
3893		4120
3894	C<ev_stat> watchers use a small hash table to distribute workload by	4121	C<ev_stat> watchers use a small hash table to distribute workload by
3895	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	4122	inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
3896	usually more than enough. If you need to manage thousands of C<ev_stat>	4123	disabled), usually more than enough. If you need to manage thousands of
3897	watchers you might want to increase this value (I<must> be a power of	4124	C<ev_stat> watchers you might want to increase this value (I<must> be a
3898	two).	4125	power of two).
3899		4126
3900	=item EV_USE_4HEAP	4127	=item EV_USE_4HEAP
3901		4128
3902	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4129	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3903	timer and periodics heaps, libev uses a 4-heap when this symbol is defined	4130	timer and periodics heaps, libev uses a 4-heap when this symbol is defined
3904	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably	4131	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
3905	faster performance with many (thousands) of watchers.	4132	faster performance with many (thousands) of watchers.
3906		4133
3907	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4134	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3908	(disabled).	4135	will be C<0>.
3909		4136
3910	=item EV_HEAP_CACHE_AT	4137	=item EV_HEAP_CACHE_AT
3911		4138
3912	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4139	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3913	timer and periodics heaps, libev can cache the timestamp (I<at>) within	4140	timer and periodics heaps, libev can cache the timestamp (I<at>) within
3914	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	4141	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3915	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	4142	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3916	but avoids random read accesses on heap changes. This improves performance	4143	but avoids random read accesses on heap changes. This improves performance
3917	noticeably with many (hundreds) of watchers.	4144	noticeably with many (hundreds) of watchers.
3918		4145
3919	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4146	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3920	(disabled).	4147	will be C<0>.
3921		4148
3922	=item EV_VERIFY	4149	=item EV_VERIFY
3923		4150
3924	Controls how much internal verification (see C<ev_loop_verify ()>) will	4151	Controls how much internal verification (see C<ev_verify ()>) will
3925	be done: If set to C<0>, no internal verification code will be compiled	4152	be done: If set to C<0>, no internal verification code will be compiled
3926	in. If set to C<1>, then verification code will be compiled in, but not	4153	in. If set to C<1>, then verification code will be compiled in, but not
3927	called. If set to C<2>, then the internal verification code will be	4154	called. If set to C<2>, then the internal verification code will be
3928	called once per loop, which can slow down libev. If set to C<3>, then the	4155	called once per loop, which can slow down libev. If set to C<3>, then the
3929	verification code will be called very frequently, which will slow down	4156	verification code will be called very frequently, which will slow down
3930	libev considerably.	4157	libev considerably.
3931		4158
3932	The default is C<1>, unless C<EV_MINIMAL> is set, in which case it will be	4159	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3933	C<0>.	4160	will be C<0>.
3934		4161
3935	=item EV_COMMON	4162	=item EV_COMMON
3936		4163
3937	By default, all watchers have a C<void *data> member. By redefining	4164	By default, all watchers have a C<void *data> member. By redefining
3938	this macro to a something else you can include more and other types of	4165	this macro to something else you can include more and other types of
3939	members. You have to define it each time you include one of the files,	4166	members. You have to define it each time you include one of the files,
3940	though, and it must be identical each time.	4167	though, and it must be identical each time.
3941		4168
3942	For example, the perl EV module uses something like this:	4169	For example, the perl EV module uses something like this:
3943		4170
…		…
3996	file.	4223	file.
3997		4224
3998	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4225	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
3999	that everybody includes and which overrides some configure choices:	4226	that everybody includes and which overrides some configure choices:
4000		4227
4001	#define EV_MINIMAL 1	4228	#define EV_FEATURES 8
4002	#define EV_USE_POLL 0	4229	#define EV_USE_SELECT 1
4003	#define EV_MULTIPLICITY 0
4004	#define EV_PERIODIC_ENABLE 0	4230	#define EV_PREPARE_ENABLE 1
		4231	#define EV_IDLE_ENABLE 1
4005	#define EV_STAT_ENABLE 0	4232	#define EV_SIGNAL_ENABLE 1
4006	#define EV_FORK_ENABLE 0	4233	#define EV_CHILD_ENABLE 1
		4234	#define EV_USE_STDEXCEPT 0
4007	#define EV_CONFIG_H <config.h>	4235	#define EV_CONFIG_H <config.h>
4008	#define EV_MINPRI 0
4009	#define EV_MAXPRI 0
4010		4236
4011	#include "ev++.h"	4237	#include "ev++.h"
4012		4238
4013	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4239	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
4014		4240
…		…
4145	userdata *u = ev_userdata (EV_A);	4371	userdata *u = ev_userdata (EV_A);
4146	pthread_mutex_lock (&u->lock);	4372	pthread_mutex_lock (&u->lock);
4147	}	4373	}
4148		4374
4149	The event loop thread first acquires the mutex, and then jumps straight	4375	The event loop thread first acquires the mutex, and then jumps straight
4150	into C<ev_loop>:	4376	into C<ev_run>:
4151		4377
4152	void *	4378	void *
4153	l_run (void *thr_arg)	4379	l_run (void *thr_arg)
4154	{	4380	{
4155	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4381	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4156		4382
4157	l_acquire (EV_A);	4383	l_acquire (EV_A);
4158	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4384	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4159	ev_loop (EV_A_ 0);	4385	ev_run (EV_A_ 0);
4160	l_release (EV_A);	4386	l_release (EV_A);
4161		4387
4162	return 0;	4388	return 0;
4163	}	4389	}
4164		4390
…		…
4216		4442
4217	=head3 COROUTINES	4443	=head3 COROUTINES
4218		4444
4219	Libev is very accommodating to coroutines ("cooperative threads"):	4445	Libev is very accommodating to coroutines ("cooperative threads"):
4220	libev fully supports nesting calls to its functions from different	4446	libev fully supports nesting calls to its functions from different
4221	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4447	coroutines (e.g. you can call C<ev_run> on the same loop from two
4222	different coroutines, and switch freely between both coroutines running	4448	different coroutines, and switch freely between both coroutines running
4223	the loop, as long as you don't confuse yourself). The only exception is	4449	the loop, as long as you don't confuse yourself). The only exception is
4224	that you must not do this from C<ev_periodic> reschedule callbacks.	4450	that you must not do this from C<ev_periodic> reschedule callbacks.
4225		4451
4226	Care has been taken to ensure that libev does not keep local state inside	4452	Care has been taken to ensure that libev does not keep local state inside
4227	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4453	C<ev_run>, and other calls do not usually allow for coroutine switches as
4228	they do not call any callbacks.	4454	they do not call any callbacks.
4229		4455
4230	=head2 COMPILER WARNINGS	4456	=head2 COMPILER WARNINGS
4231		4457
4232	Depending on your compiler and compiler settings, you might get no or a	4458	Depending on your compiler and compiler settings, you might get no or a
…		…
4243	maintainable.	4469	maintainable.
4244		4470
4245	And of course, some compiler warnings are just plain stupid, or simply	4471	And of course, some compiler warnings are just plain stupid, or simply
4246	wrong (because they don't actually warn about the condition their message	4472	wrong (because they don't actually warn about the condition their message
4247	seems to warn about). For example, certain older gcc versions had some	4473	seems to warn about). For example, certain older gcc versions had some
4248	warnings that resulted an extreme number of false positives. These have	4474	warnings that resulted in an extreme number of false positives. These have
4249	been fixed, but some people still insist on making code warn-free with	4475	been fixed, but some people still insist on making code warn-free with
4250	such buggy versions.	4476	such buggy versions.
4251		4477
4252	While libev is written to generate as few warnings as possible,	4478	While libev is written to generate as few warnings as possible,
4253	"warn-free" code is not a goal, and it is recommended not to build libev	4479	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4289	I suggest using suppression lists.	4515	I suggest using suppression lists.
4290		4516
4291		4517
4292	=head1 PORTABILITY NOTES	4518	=head1 PORTABILITY NOTES
4293		4519
		4520	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4521
		4522	GNU/Linux is the only common platform that supports 64 bit file/large file
		4523	interfaces but I<disables> them by default.
		4524
		4525	That means that libev compiled in the default environment doesn't support
		4526	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4527
		4528	Unfortunately, many programs try to work around this GNU/Linux issue
		4529	by enabling the large file API, which makes them incompatible with the
		4530	standard libev compiled for their system.
		4531
		4532	Likewise, libev cannot enable the large file API itself as this would
		4533	suddenly make it incompatible to the default compile time environment,
		4534	i.e. all programs not using special compile switches.
		4535
		4536	=head2 OS/X AND DARWIN BUGS
		4537
		4538	The whole thing is a bug if you ask me - basically any system interface
		4539	you touch is broken, whether it is locales, poll, kqueue or even the
		4540	OpenGL drivers.
		4541
		4542	=head3 C<kqueue> is buggy
		4543
		4544	The kqueue syscall is broken in all known versions - most versions support
		4545	only sockets, many support pipes.
		4546
		4547	Libev tries to work around this by not using C<kqueue> by default on this
		4548	rotten platform, but of course you can still ask for it when creating a
		4549	loop - embedding a socket-only kqueue loop into a select-based one is
		4550	probably going to work well.
		4551
		4552	=head3 C<poll> is buggy
		4553
		4554	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4555	implementation by something calling C<kqueue> internally around the 10.5.6
		4556	release, so now C<kqueue> I<and> C<poll> are broken.
		4557
		4558	Libev tries to work around this by not using C<poll> by default on
		4559	this rotten platform, but of course you can still ask for it when creating
		4560	a loop.
		4561
		4562	=head3 C<select> is buggy
		4563
		4564	All that's left is C<select>, and of course Apple found a way to fuck this
		4565	one up as well: On OS/X, C<select> actively limits the number of file
		4566	descriptors you can pass in to 1024 - your program suddenly crashes when
		4567	you use more.
		4568
		4569	There is an undocumented "workaround" for this - defining
		4570	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4571	work on OS/X.
		4572
		4573	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4574
		4575	=head3 C<errno> reentrancy
		4576
		4577	The default compile environment on Solaris is unfortunately so
		4578	thread-unsafe that you can't even use components/libraries compiled
		4579	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4580	defined by default. A valid, if stupid, implementation choice.
		4581
		4582	If you want to use libev in threaded environments you have to make sure
		4583	it's compiled with C<_REENTRANT> defined.
		4584
		4585	=head3 Event port backend
		4586
		4587	The scalable event interface for Solaris is called "event
		4588	ports". Unfortunately, this mechanism is very buggy in all major
		4589	releases. If you run into high CPU usage, your program freezes or you get
		4590	a large number of spurious wakeups, make sure you have all the relevant
		4591	and latest kernel patches applied. No, I don't know which ones, but there
		4592	are multiple ones to apply, and afterwards, event ports actually work
		4593	great.
		4594
		4595	If you can't get it to work, you can try running the program by setting
		4596	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4597	C<select> backends.
		4598
		4599	=head2 AIX POLL BUG
		4600
		4601	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4602	this by trying to avoid the poll backend altogether (i.e. it's not even
		4603	compiled in), which normally isn't a big problem as C<select> works fine
		4604	with large bitsets on AIX, and AIX is dead anyway.
		4605
4294	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4606	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4607
		4608	=head3 General issues
4295		4609
4296	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4610	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4297	requires, and its I/O model is fundamentally incompatible with the POSIX	4611	requires, and its I/O model is fundamentally incompatible with the POSIX
4298	model. Libev still offers limited functionality on this platform in	4612	model. Libev still offers limited functionality on this platform in
4299	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4613	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4300	descriptors. This only applies when using Win32 natively, not when using	4614	descriptors. This only applies when using Win32 natively, not when using
4301	e.g. cygwin.	4615	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4616	as every compielr comes with a slightly differently broken/incompatible
		4617	environment.
4302		4618
4303	Lifting these limitations would basically require the full	4619	Lifting these limitations would basically require the full
4304	re-implementation of the I/O system. If you are into these kinds of	4620	re-implementation of the I/O system. If you are into this kind of thing,
4305	things, then note that glib does exactly that for you in a very portable	4621	then note that glib does exactly that for you in a very portable way (note
4306	way (note also that glib is the slowest event library known to man).	4622	also that glib is the slowest event library known to man).
4307		4623
4308	There is no supported compilation method available on windows except	4624	There is no supported compilation method available on windows except
4309	embedding it into other applications.	4625	embedding it into other applications.
4310		4626
4311	Sensible signal handling is officially unsupported by Microsoft - libev	4627	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4339	you do I<not> compile the F<ev.c> or any other embedded source files!):	4655	you do I<not> compile the F<ev.c> or any other embedded source files!):
4340		4656
4341	#include "evwrap.h"	4657	#include "evwrap.h"
4342	#include "ev.c"	4658	#include "ev.c"
4343		4659
4344	=over 4
4345
4346	=item The winsocket select function	4660	=head3 The winsocket C<select> function
4347		4661
4348	The winsocket C<select> function doesn't follow POSIX in that it	4662	The winsocket C<select> function doesn't follow POSIX in that it
4349	requires socket I<handles> and not socket I<file descriptors> (it is	4663	requires socket I<handles> and not socket I<file descriptors> (it is
4350	also extremely buggy). This makes select very inefficient, and also	4664	also extremely buggy). This makes select very inefficient, and also
4351	requires a mapping from file descriptors to socket handles (the Microsoft	4665	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4360	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4674	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4361		4675
4362	Note that winsockets handling of fd sets is O(n), so you can easily get a	4676	Note that winsockets handling of fd sets is O(n), so you can easily get a
4363	complexity in the O(n²) range when using win32.	4677	complexity in the O(n²) range when using win32.
4364		4678
4365	=item Limited number of file descriptors	4679	=head3 Limited number of file descriptors
4366		4680
4367	Windows has numerous arbitrary (and low) limits on things.	4681	Windows has numerous arbitrary (and low) limits on things.
4368		4682
4369	Early versions of winsocket's select only supported waiting for a maximum	4683	Early versions of winsocket's select only supported waiting for a maximum
4370	of C<64> handles (probably owning to the fact that all windows kernels	4684	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4385	runtime libraries. This might get you to about C<512> or C<2048> sockets	4699	runtime libraries. This might get you to about C<512> or C<2048> sockets
4386	(depending on windows version and/or the phase of the moon). To get more,	4700	(depending on windows version and/or the phase of the moon). To get more,
4387	you need to wrap all I/O functions and provide your own fd management, but	4701	you need to wrap all I/O functions and provide your own fd management, but
4388	the cost of calling select (O(n²)) will likely make this unworkable.	4702	the cost of calling select (O(n²)) will likely make this unworkable.
4389		4703
4390	=back
4391
4392	=head2 PORTABILITY REQUIREMENTS	4704	=head2 PORTABILITY REQUIREMENTS
4393		4705
4394	In addition to a working ISO-C implementation and of course the	4706	In addition to a working ISO-C implementation and of course the
4395	backend-specific APIs, libev relies on a few additional extensions:	4707	backend-specific APIs, libev relies on a few additional extensions:
4396		4708
…		…
4434	watchers.	4746	watchers.
4435		4747
4436	=item C<double> must hold a time value in seconds with enough accuracy	4748	=item C<double> must hold a time value in seconds with enough accuracy
4437		4749
4438	The type C<double> is used to represent timestamps. It is required to	4750	The type C<double> is used to represent timestamps. It is required to
4439	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4751	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4440	enough for at least into the year 4000. This requirement is fulfilled by	4752	good enough for at least into the year 4000 with millisecond accuracy
		4753	(the design goal for libev). This requirement is overfulfilled by
4441	implementations implementing IEEE 754, which is basically all existing	4754	implementations using IEEE 754, which is basically all existing ones. With
4442	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4755	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4443	2200.
4444		4756
4445	=back	4757	=back
4446		4758
4447	If you know of other additional requirements drop me a note.	4759	If you know of other additional requirements drop me a note.
4448		4760
…		…
4516	involves iterating over all running async watchers or all signal numbers.	4828	involves iterating over all running async watchers or all signal numbers.
4517		4829
4518	=back	4830	=back
4519		4831
4520		4832
		4833	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4834
		4835	The major version 4 introduced some minor incompatible changes to the API.
		4836
		4837	At the moment, the C<ev.h> header file tries to implement superficial
		4838	compatibility, so most programs should still compile. Those might be
		4839	removed in later versions of libev, so better update early than late.
		4840
		4841	=over 4
		4842
		4843	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4844
		4845	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4846
		4847	ev_loop_destroy (EV_DEFAULT);
		4848	ev_loop_fork (EV_DEFAULT);
		4849
		4850	=item function/symbol renames
		4851
		4852	A number of functions and symbols have been renamed:
		4853
		4854	ev_loop => ev_run
		4855	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4856	EVLOOP_ONESHOT => EVRUN_ONCE
		4857
		4858	ev_unloop => ev_break
		4859	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4860	EVUNLOOP_ONE => EVBREAK_ONE
		4861	EVUNLOOP_ALL => EVBREAK_ALL
		4862
		4863	EV_TIMEOUT => EV_TIMER
		4864
		4865	ev_loop_count => ev_iteration
		4866	ev_loop_depth => ev_depth
		4867	ev_loop_verify => ev_verify
		4868
		4869	Most functions working on C<struct ev_loop> objects don't have an
		4870	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4871	associated constants have been renamed to not collide with the C<struct
		4872	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4873	as all other watcher types. Note that C<ev_loop_fork> is still called
		4874	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4875	typedef.
		4876
		4877	=item C<EV_COMPAT3> backwards compatibility mechanism
		4878
		4879	The backward compatibility mechanism can be controlled by
		4880	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4881	section.
		4882
		4883	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4884
		4885	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4886	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4887	and work, but the library code will of course be larger.
		4888
		4889	=back
		4890
		4891
4521	=head1 GLOSSARY	4892	=head1 GLOSSARY
4522		4893
4523	=over 4	4894	=over 4
4524		4895
4525	=item active	4896	=item active
4526		4897
4527	A watcher is active as long as it has been started (has been attached to	4898	A watcher is active as long as it has been started and not yet stopped.
4528	an event loop) but not yet stopped (disassociated from the event loop).	4899	See L<WATCHER STATES> for details.
4529		4900
4530	=item application	4901	=item application
4531		4902
4532	In this document, an application is whatever is using libev.	4903	In this document, an application is whatever is using libev.
		4904
		4905	=item backend
		4906
		4907	The part of the code dealing with the operating system interfaces.
4533		4908
4534	=item callback	4909	=item callback
4535		4910
4536	The address of a function that is called when some event has been	4911	The address of a function that is called when some event has been
4537	detected. Callbacks are being passed the event loop, the watcher that	4912	detected. Callbacks are being passed the event loop, the watcher that
4538	received the event, and the actual event bitset.	4913	received the event, and the actual event bitset.
4539		4914
4540	=item callback invocation	4915	=item callback/watcher invocation
4541		4916
4542	The act of calling the callback associated with a watcher.	4917	The act of calling the callback associated with a watcher.
4543		4918
4544	=item event	4919	=item event
4545		4920
4546	A change of state of some external event, such as data now being available	4921	A change of state of some external event, such as data now being available
4547	for reading on a file descriptor, time having passed or simply not having	4922	for reading on a file descriptor, time having passed or simply not having
4548	any other events happening anymore.	4923	any other events happening anymore.
4549		4924
4550	In libev, events are represented as single bits (such as C<EV_READ> or	4925	In libev, events are represented as single bits (such as C<EV_READ> or
4551	C<EV_TIMEOUT>).	4926	C<EV_TIMER>).
4552		4927
4553	=item event library	4928	=item event library
4554		4929
4555	A software package implementing an event model and loop.	4930	A software package implementing an event model and loop.
4556		4931
…		…
4564	The model used to describe how an event loop handles and processes	4939	The model used to describe how an event loop handles and processes
4565	watchers and events.	4940	watchers and events.
4566		4941
4567	=item pending	4942	=item pending
4568		4943
4569	A watcher is pending as soon as the corresponding event has been detected,	4944	A watcher is pending as soon as the corresponding event has been
4570	and stops being pending as soon as the watcher will be invoked or its	4945	detected. See L<WATCHER STATES> for details.
4571	pending status is explicitly cleared by the application.
4572
4573	A watcher can be pending, but not active. Stopping a watcher also clears
4574	its pending status.
4575		4946
4576	=item real time	4947	=item real time
4577		4948
4578	The physical time that is observed. It is apparently strictly monotonic :)	4949	The physical time that is observed. It is apparently strictly monotonic :)
4579		4950
…		…
4586	=item watcher	4957	=item watcher
4587		4958
4588	A data structure that describes interest in certain events. Watchers need	4959	A data structure that describes interest in certain events. Watchers need
4589	to be started (attached to an event loop) before they can receive events.	4960	to be started (attached to an event loop) before they can receive events.
4590		4961
4591	=item watcher invocation
4592
4593	The act of calling the callback associated with a watcher.
4594
4595	=back	4962	=back
4596		4963
4597	=head1 AUTHOR	4964	=head1 AUTHOR
4598		4965
4599	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4966	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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