ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.277 by root, Thu Dec 31 06:50:17 2009 UTC vs.
Revision 1.323 by root, Sun Oct 24 18:01:26 2010 UTC

…		…
26	puts ("stdin ready");	26	puts ("stdin ready");
27	// for one-shot events, one must manually stop the watcher	27	// for one-shot events, one must manually stop the watcher
28	// with its corresponding stop function.	28	// with its corresponding stop function.
29	ev_io_stop (EV_A_ w);	29	ev_io_stop (EV_A_ w);
30		30
31	// this causes all nested ev_loop's to stop iterating	31	// this causes all nested ev_run's to stop iterating
32	ev_unloop (EV_A_ EVUNLOOP_ALL);	32	ev_break (EV_A_ EVBREAK_ALL);
33	}	33	}
34		34
35	// another callback, this time for a time-out	35	// another callback, this time for a time-out
36	static void	36	static void
37	timeout_cb (EV_P_ ev_timer *w, int revents)	37	timeout_cb (EV_P_ ev_timer *w, int revents)
38	{	38	{
39	puts ("timeout");	39	puts ("timeout");
40	// this causes the innermost ev_loop to stop iterating	40	// this causes the innermost ev_run to stop iterating
41	ev_unloop (EV_A_ EVUNLOOP_ONE);	41	ev_break (EV_A_ EVBREAK_ONE);
42	}	42	}
43		43
44	int	44	int
45	main (void)	45	main (void)
46	{	46	{
47	// use the default event loop unless you have special needs	47	// use the default event loop unless you have special needs
48	struct ev_loop *loop = ev_default_loop (0);	48	struct ev_loop *loop = EV_DEFAULT;
49		49
50	// initialise an io watcher, then start it	50	// initialise an io watcher, then start it
51	// this one will watch for stdin to become readable	51	// this one will watch for stdin to become readable
52	ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);	52	ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
53	ev_io_start (loop, &stdin_watcher);	53	ev_io_start (loop, &stdin_watcher);
…		…
56	// simple non-repeating 5.5 second timeout	56	// simple non-repeating 5.5 second timeout
57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
58	ev_timer_start (loop, &timeout_watcher);	58	ev_timer_start (loop, &timeout_watcher);
59		59
60	// now wait for events to arrive	60	// now wait for events to arrive
61	ev_loop (loop, 0);	61	ev_run (loop, 0);
62		62
63	// unloop was called, so exit	63	// unloop was called, so exit
64	return 0;	64	return 0;
65	}	65	}
66		66
…		…
75	While this document tries to be as complete as possible in documenting	75	While this document tries to be as complete as possible in documenting
76	libev, its usage and the rationale behind its design, it is not a tutorial	76	libev, its usage and the rationale behind its design, it is not a tutorial
77	on event-based programming, nor will it introduce event-based programming	77	on event-based programming, nor will it introduce event-based programming
78	with libev.	78	with libev.
79		79
80	Familarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
82		82
83	=head1 ABOUT LIBEV	83	=head1 ABOUT LIBEV
84		84
85	Libev is an event loop: you register interest in certain events (such as a	85	Libev is an event loop: you register interest in certain events (such as a
…		…
124	this argument.	124	this argument.
125		125
126	=head2 TIME REPRESENTATION	126	=head2 TIME REPRESENTATION
127		127
128	Libev represents time as a single floating point number, representing	128	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (somewhere	129	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	near the beginning of 1970, details are complicated, don't ask). This	130	somewhere near the beginning of 1970, details are complicated, don't
131	type is called C<ev_tstamp>, which is what you should use too. It usually	131	ask). This type is called C<ev_tstamp>, which is what you should use
132	aliases to the C<double> type in C. When you need to do any calculations	132	too. It usually aliases to the C<double> type in C. When you need to do
133	on it, you should treat it as some floating point value. Unlike the name	133	any calculations on it, you should treat it as some floating point value.
		134
134	component C<stamp> might indicate, it is also used for time differences	135	Unlike the name component C<stamp> might indicate, it is also used for
135	throughout libev.	136	time differences (e.g. delays) throughout libev.
136		137
137	=head1 ERROR HANDLING	138	=head1 ERROR HANDLING
138		139
139	Libev knows three classes of errors: operating system errors, usage errors	140	Libev knows three classes of errors: operating system errors, usage errors
140	and internal errors (bugs).	141	and internal errors (bugs).
…		…
164		165
165	=item ev_tstamp ev_time ()	166	=item ev_tstamp ev_time ()
166		167
167	Returns the current time as libev would use it. Please note that the	168	Returns the current time as libev would use it. Please note that the
168	C<ev_now> function is usually faster and also often returns the timestamp	169	C<ev_now> function is usually faster and also often returns the timestamp
169	you actually want to know.	170	you actually want to know. Also interesting is the combination of
		171	C<ev_update_now> and C<ev_now>.
170		172
171	=item ev_sleep (ev_tstamp interval)	173	=item ev_sleep (ev_tstamp interval)
172		174
173	Sleep for the given interval: The current thread will be blocked until	175	Sleep for the given interval: The current thread will be blocked until
174	either it is interrupted or the given time interval has passed. Basically	176	either it is interrupted or the given time interval has passed. Basically
…		…
191	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
192	compatible to older versions, so a larger minor version alone is usually	194	compatible to older versions, so a larger minor version alone is usually
193	not a problem.	195	not a problem.
194		196
195	Example: Make sure we haven't accidentally been linked against the wrong	197	Example: Make sure we haven't accidentally been linked against the wrong
196	version.	198	version (note, however, that this will not detect other ABI mismatches,
		199	such as LFS or reentrancy).
197		200
198	assert (("libev version mismatch",	201	assert (("libev version mismatch",
199	ev_version_major () == EV_VERSION_MAJOR	202	ev_version_major () == EV_VERSION_MAJOR
200	&& ev_version_minor () >= EV_VERSION_MINOR));	203	&& ev_version_minor () >= EV_VERSION_MINOR));
201		204
…		…
212	assert (("sorry, no epoll, no sex",	215	assert (("sorry, no epoll, no sex",
213	ev_supported_backends () & EVBACKEND_EPOLL));	216	ev_supported_backends () & EVBACKEND_EPOLL));
214		217
215	=item unsigned int ev_recommended_backends ()	218	=item unsigned int ev_recommended_backends ()
216		219
217	Return the set of all backends compiled into this binary of libev and also	220	Return the set of all backends compiled into this binary of libev and
218	recommended for this platform. This set is often smaller than the one	221	also recommended for this platform, meaning it will work for most file
		222	descriptor types. This set is often smaller than the one returned by
219	returned by C<ev_supported_backends>, as for example kqueue is broken on	223	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
220	most BSDs and will not be auto-detected unless you explicitly request it	224	and will not be auto-detected unless you explicitly request it (assuming
221	(assuming you know what you are doing). This is the set of backends that	225	you know what you are doing). This is the set of backends that libev will
222	libev will probe for if you specify no backends explicitly.	226	probe for if you specify no backends explicitly.
223		227
224	=item unsigned int ev_embeddable_backends ()	228	=item unsigned int ev_embeddable_backends ()
225		229
226	Returns the set of backends that are embeddable in other event loops. This	230	Returns the set of backends that are embeddable in other event loops. This
227	is the theoretical, all-platform, value. To find which backends	231	value is platform-specific but can include backends not available on the
228	might be supported on the current system, you would need to look at	232	current system. To find which embeddable backends might be supported on
229	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	233	the current system, you would need to look at C<ev_embeddable_backends ()
230	recommended ones.	234	& ev_supported_backends ()>, likewise for recommended ones.
231		235
232	See the description of C<ev_embed> watchers for more info.	236	See the description of C<ev_embed> watchers for more info.
233		237
234	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]	238	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]
235		239
…		…
289	...	293	...
290	ev_set_syserr_cb (fatal_error);	294	ev_set_syserr_cb (fatal_error);
291		295
292	=back	296	=back
293		297
294	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	298	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
295		299
296	An event loop is described by a C<struct ev_loop *> (the C<struct>	300	An event loop is described by a C<struct ev_loop *> (the C<struct> is
297	is I<not> optional in this case, as there is also an C<ev_loop>	301	I<not> optional in this case unless libev 3 compatibility is disabled, as
298	I<function>).	302	libev 3 had an C<ev_loop> function colliding with the struct name).
299		303
300	The library knows two types of such loops, the I<default> loop, which	304	The library knows two types of such loops, the I<default> loop, which
301	supports signals and child events, and dynamically created loops which do	305	supports signals and child events, and dynamically created event loops
302	not.	306	which do not.
303		307
304	=over 4	308	=over 4
305		309
306	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
307		311
308	This will initialise the default event loop if it hasn't been initialised	312	This returns the "default" event loop object, which is what you should
309	yet and return it. If the default loop could not be initialised, returns	313	normally use when you just need "the event loop". Event loop objects and
310	false. If it already was initialised it simply returns it (and ignores the	314	the C<flags> parameter are described in more detail in the entry for
311	flags. If that is troubling you, check C<ev_backend ()> afterwards).	315	C<ev_loop_new>.
		316
		317	If the default loop is already initialised then this function simply
		318	returns it (and ignores the flags. If that is troubling you, check
		319	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		320	flags, which should almost always be C<0>, unless the caller is also the
		321	one calling C<ev_run> or otherwise qualifies as "the main program".
312		322
313	If you don't know what event loop to use, use the one returned from this	323	If you don't know what event loop to use, use the one returned from this
314	function.	324	function (or via the C<EV_DEFAULT> macro).
315		325
316	Note that this function is I<not> thread-safe, so if you want to use it	326	Note that this function is I<not> thread-safe, so if you want to use it
317	from multiple threads, you have to lock (note also that this is unlikely,	327	from multiple threads, you have to employ some kind of mutex (note also
318	as loops cannot be shared easily between threads anyway).	328	that this case is unlikely, as loops cannot be shared easily between
		329	threads anyway).
319		330
320	The default loop is the only loop that can handle C<ev_signal> and	331	The default loop is the only loop that can handle C<ev_child> watchers,
321	C<ev_child> watchers, and to do this, it always registers a handler	332	and to do this, it always registers a handler for C<SIGCHLD>. If this is
322	for C<SIGCHLD>. If this is a problem for your application you can either	333	a problem for your application you can either create a dynamic loop with
323	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	334	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
324	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	335	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
325	C<ev_default_init>.	336
		337	Example: This is the most typical usage.
		338
		339	if (!ev_default_loop (0))
		340	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		341
		342	Example: Restrict libev to the select and poll backends, and do not allow
		343	environment settings to be taken into account:
		344
		345	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
		346
		347	=item struct ev_loop *ev_loop_new (unsigned int flags)
		348
		349	This will create and initialise a new event loop object. If the loop
		350	could not be initialised, returns false.
		351
		352	Note that this function I<is> thread-safe, and one common way to use
		353	libev with threads is indeed to create one loop per thread, and using the
		354	default loop in the "main" or "initial" thread.
326		355
327	The flags argument can be used to specify special behaviour or specific	356	The flags argument can be used to specify special behaviour or specific
328	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	357	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
329		358
330	The following flags are supported:	359	The following flags are supported:
…		…
345	useful to try out specific backends to test their performance, or to work	374	useful to try out specific backends to test their performance, or to work
346	around bugs.	375	around bugs.
347		376
348	=item C<EVFLAG_FORKCHECK>	377	=item C<EVFLAG_FORKCHECK>
349		378
350	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	379	Instead of calling C<ev_loop_fork> manually after a fork, you can also
351	a fork, you can also make libev check for a fork in each iteration by	380	make libev check for a fork in each iteration by enabling this flag.
352	enabling this flag.
353		381
354	This works by calling C<getpid ()> on every iteration of the loop,	382	This works by calling C<getpid ()> on every iteration of the loop,
355	and thus this might slow down your event loop if you do a lot of loop	383	and thus this might slow down your event loop if you do a lot of loop
356	iterations and little real work, but is usually not noticeable (on my	384	iterations and little real work, but is usually not noticeable (on my
357	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	385	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
…		…
374		402
375	=item C<EVFLAG_SIGNALFD>	403	=item C<EVFLAG_SIGNALFD>
376		404
377	When this flag is specified, then libev will attempt to use the	405	When this flag is specified, then libev will attempt to use the
378	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API	406	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API
379	delivers signals synchronously, which makes is both faster and might make	407	delivers signals synchronously, which makes it both faster and might make
380	it possible to get the queued signal data.	408	it possible to get the queued signal data. It can also simplify signal
		409	handling with threads, as long as you properly block signals in your
		410	threads that are not interested in handling them.
381		411
382	Signalfd will not be used by default as this changes your signal mask, and	412	Signalfd will not be used by default as this changes your signal mask, and
383	there are a lot of shoddy libraries and programs (glib's threadpool for	413	there are a lot of shoddy libraries and programs (glib's threadpool for
384	example) that can't properly initialise their signal masks.	414	example) that can't properly initialise their signal masks.
385		415
…		…
437	of course I<doesn't>, and epoll just loves to report events for totally	467	of course I<doesn't>, and epoll just loves to report events for totally
438	I<different> file descriptors (even already closed ones, so one cannot	468	I<different> file descriptors (even already closed ones, so one cannot
439	even remove them from the set) than registered in the set (especially	469	even remove them from the set) than registered in the set (especially
440	on SMP systems). Libev tries to counter these spurious notifications by	470	on SMP systems). Libev tries to counter these spurious notifications by
441	employing an additional generation counter and comparing that against the	471	employing an additional generation counter and comparing that against the
442	events to filter out spurious ones, recreating the set when required.	472	events to filter out spurious ones, recreating the set when required. Last
		473	not least, it also refuses to work with some file descriptors which work
		474	perfectly fine with C<select> (files, many character devices...).
443		475
444	While stopping, setting and starting an I/O watcher in the same iteration	476	While stopping, setting and starting an I/O watcher in the same iteration
445	will result in some caching, there is still a system call per such	477	will result in some caching, there is still a system call per such
446	incident (because the same I<file descriptor> could point to a different	478	incident (because the same I<file descriptor> could point to a different
447	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	479	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
545	If one or more of the backend flags are or'ed into the flags value,	577	If one or more of the backend flags are or'ed into the flags value,
546	then only these backends will be tried (in the reverse order as listed	578	then only these backends will be tried (in the reverse order as listed
547	here). If none are specified, all backends in C<ev_recommended_backends	579	here). If none are specified, all backends in C<ev_recommended_backends
548	()> will be tried.	580	()> will be tried.
549		581
550	Example: This is the most typical usage.
551
552	if (!ev_default_loop (0))
553	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
554
555	Example: Restrict libev to the select and poll backends, and do not allow
556	environment settings to be taken into account:
557
558	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
559
560	Example: Use whatever libev has to offer, but make sure that kqueue is
561	used if available (warning, breaks stuff, best use only with your own
562	private event loop and only if you know the OS supports your types of
563	fds):
564
565	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
566
567	=item struct ev_loop *ev_loop_new (unsigned int flags)
568
569	Similar to C<ev_default_loop>, but always creates a new event loop that is
570	always distinct from the default loop. Unlike the default loop, it cannot
571	handle signal and child watchers, and attempts to do so will be greeted by
572	undefined behaviour (or a failed assertion if assertions are enabled).
573
574	Note that this function I<is> thread-safe, and the recommended way to use
575	libev with threads is indeed to create one loop per thread, and using the
576	default loop in the "main" or "initial" thread.
577
578	Example: Try to create a event loop that uses epoll and nothing else.	582	Example: Try to create a event loop that uses epoll and nothing else.
579		583
580	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
581	if (!epoller)	585	if (!epoller)
582	fatal ("no epoll found here, maybe it hides under your chair");	586	fatal ("no epoll found here, maybe it hides under your chair");
583		587
		588	Example: Use whatever libev has to offer, but make sure that kqueue is
		589	used if available.
		590
		591	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
		592
584	=item ev_default_destroy ()	593	=item ev_loop_destroy (loop)
585		594
586	Destroys the default loop again (frees all memory and kernel state	595	Destroys an event loop object (frees all memory and kernel state
587	etc.). None of the active event watchers will be stopped in the normal	596	etc.). None of the active event watchers will be stopped in the normal
588	sense, so e.g. C<ev_is_active> might still return true. It is your	597	sense, so e.g. C<ev_is_active> might still return true. It is your
589	responsibility to either stop all watchers cleanly yourself I<before>	598	responsibility to either stop all watchers cleanly yourself I<before>
590	calling this function, or cope with the fact afterwards (which is usually	599	calling this function, or cope with the fact afterwards (which is usually
591	the easiest thing, you can just ignore the watchers and/or C<free ()> them	600	the easiest thing, you can just ignore the watchers and/or C<free ()> them
…		…
593		602
594	Note that certain global state, such as signal state (and installed signal	603	Note that certain global state, such as signal state (and installed signal
595	handlers), will not be freed by this function, and related watchers (such	604	handlers), will not be freed by this function, and related watchers (such
596	as signal and child watchers) would need to be stopped manually.	605	as signal and child watchers) would need to be stopped manually.
597		606
598	In general it is not advisable to call this function except in the	607	This function is normally used on loop objects allocated by
599	rare occasion where you really need to free e.g. the signal handling	608	C<ev_loop_new>, but it can also be used on the default loop returned by
		609	C<ev_default_loop>, in which case it is not thread-safe.
		610
		611	Note that it is not advisable to call this function on the default loop
		612	except in the rare occasion where you really need to free it's resources.
600	pipe fds. If you need dynamically allocated loops it is better to use	613	If you need dynamically allocated loops it is better to use C<ev_loop_new>
601	C<ev_loop_new> and C<ev_loop_destroy>.	614	and C<ev_loop_destroy>.
602		615
603	=item ev_loop_destroy (loop)	616	=item ev_loop_fork (loop)
604		617
605	Like C<ev_default_destroy>, but destroys an event loop created by an
606	earlier call to C<ev_loop_new>.
607
608	=item ev_default_fork ()
609
610	This function sets a flag that causes subsequent C<ev_loop> iterations	618	This function sets a flag that causes subsequent C<ev_run> iterations to
611	to reinitialise the kernel state for backends that have one. Despite the	619	reinitialise the kernel state for backends that have one. Despite the
612	name, you can call it anytime, but it makes most sense after forking, in	620	name, you can call it anytime, but it makes most sense after forking, in
613	the child process (or both child and parent, but that again makes little	621	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
614	sense). You I<must> call it in the child before using any of the libev	622	child before resuming or calling C<ev_run>.
615	functions, and it will only take effect at the next C<ev_loop> iteration.	623
		624	Again, you I<have> to call it on I<any> loop that you want to re-use after
		625	a fork, I<even if you do not plan to use the loop in the parent>. This is
		626	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
		627	during fork.
616		628
617	On the other hand, you only need to call this function in the child	629	On the other hand, you only need to call this function in the child
618	process if and only if you want to use the event library in the child. If	630	process if and only if you want to use the event loop in the child. If
619	you just fork+exec, you don't have to call it at all.	631	you just fork+exec or create a new loop in the child, you don't have to
		632	call it at all (in fact, C<epoll> is so badly broken that it makes a
		633	difference, but libev will usually detect this case on its own and do a
		634	costly reset of the backend).
620		635
621	The function itself is quite fast and it's usually not a problem to call	636	The function itself is quite fast and it's usually not a problem to call
622	it just in case after a fork. To make this easy, the function will fit in	637	it just in case after a fork.
623	quite nicely into a call to C<pthread_atfork>:
624		638
		639	Example: Automate calling C<ev_loop_fork> on the default loop when
		640	using pthreads.
		641
		642	static void
		643	post_fork_child (void)
		644	{
		645	ev_loop_fork (EV_DEFAULT);
		646	}
		647
		648	...
625	pthread_atfork (0, 0, ev_default_fork);	649	pthread_atfork (0, 0, post_fork_child);
626
627	=item ev_loop_fork (loop)
628
629	Like C<ev_default_fork>, but acts on an event loop created by
630	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
631	after fork that you want to re-use in the child, and how you do this is
632	entirely your own problem.
633		650
634	=item int ev_is_default_loop (loop)	651	=item int ev_is_default_loop (loop)
635		652
636	Returns true when the given loop is, in fact, the default loop, and false	653	Returns true when the given loop is, in fact, the default loop, and false
637	otherwise.	654	otherwise.
638		655
639	=item unsigned int ev_loop_count (loop)	656	=item unsigned int ev_iteration (loop)
640		657
641	Returns the count of loop iterations for the loop, which is identical to	658	Returns the current iteration count for the event loop, which is identical
642	the number of times libev did poll for new events. It starts at C<0> and	659	to the number of times libev did poll for new events. It starts at C<0>
643	happily wraps around with enough iterations.	660	and happily wraps around with enough iterations.
644		661
645	This value can sometimes be useful as a generation counter of sorts (it	662	This value can sometimes be useful as a generation counter of sorts (it
646	"ticks" the number of loop iterations), as it roughly corresponds with	663	"ticks" the number of loop iterations), as it roughly corresponds with
647	C<ev_prepare> and C<ev_check> calls.	664	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		665	prepare and check phases.
648		666
649	=item unsigned int ev_loop_depth (loop)	667	=item unsigned int ev_depth (loop)
650		668
651	Returns the number of times C<ev_loop> was entered minus the number of	669	Returns the number of times C<ev_run> was entered minus the number of
652	times C<ev_loop> was exited, in other words, the recursion depth.	670	times C<ev_run> was exited, in other words, the recursion depth.
653		671
654	Outside C<ev_loop>, this number is zero. In a callback, this number is	672	Outside C<ev_run>, this number is zero. In a callback, this number is
655	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	673	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
656	in which case it is higher.	674	in which case it is higher.
657		675
658	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	676	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
659	etc.), doesn't count as exit.	677	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		678	ungentleman-like behaviour unless it's really convenient.
660		679
661	=item unsigned int ev_backend (loop)	680	=item unsigned int ev_backend (loop)
662		681
663	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	682	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
664	use.	683	use.
…		…
673		692
674	=item ev_now_update (loop)	693	=item ev_now_update (loop)
675		694
676	Establishes the current time by querying the kernel, updating the time	695	Establishes the current time by querying the kernel, updating the time
677	returned by C<ev_now ()> in the progress. This is a costly operation and	696	returned by C<ev_now ()> in the progress. This is a costly operation and
678	is usually done automatically within C<ev_loop ()>.	697	is usually done automatically within C<ev_run ()>.
679		698
680	This function is rarely useful, but when some event callback runs for a	699	This function is rarely useful, but when some event callback runs for a
681	very long time without entering the event loop, updating libev's idea of	700	very long time without entering the event loop, updating libev's idea of
682	the current time is a good idea.	701	the current time is a good idea.
683		702
…		…
685		704
686	=item ev_suspend (loop)	705	=item ev_suspend (loop)
687		706
688	=item ev_resume (loop)	707	=item ev_resume (loop)
689		708
690	These two functions suspend and resume a loop, for use when the loop is	709	These two functions suspend and resume an event loop, for use when the
691	not used for a while and timeouts should not be processed.	710	loop is not used for a while and timeouts should not be processed.
692		711
693	A typical use case would be an interactive program such as a game: When	712	A typical use case would be an interactive program such as a game: When
694	the user presses C<^Z> to suspend the game and resumes it an hour later it	713	the user presses C<^Z> to suspend the game and resumes it an hour later it
695	would be best to handle timeouts as if no time had actually passed while	714	would be best to handle timeouts as if no time had actually passed while
696	the program was suspended. This can be achieved by calling C<ev_suspend>	715	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
698	C<ev_resume> directly afterwards to resume timer processing.	717	C<ev_resume> directly afterwards to resume timer processing.
699		718
700	Effectively, all C<ev_timer> watchers will be delayed by the time spend	719	Effectively, all C<ev_timer> watchers will be delayed by the time spend
701	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	720	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
702	will be rescheduled (that is, they will lose any events that would have	721	will be rescheduled (that is, they will lose any events that would have
703	occured while suspended).	722	occurred while suspended).
704		723
705	After calling C<ev_suspend> you B<must not> call I<any> function on the	724	After calling C<ev_suspend> you B<must not> call I<any> function on the
706	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	725	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
707	without a previous call to C<ev_suspend>.	726	without a previous call to C<ev_suspend>.
708		727
709	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	728	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
710	event loop time (see C<ev_now_update>).	729	event loop time (see C<ev_now_update>).
711		730
712	=item ev_loop (loop, int flags)	731	=item ev_run (loop, int flags)
713		732
714	Finally, this is it, the event handler. This function usually is called	733	Finally, this is it, the event handler. This function usually is called
715	after you have initialised all your watchers and you want to start	734	after you have initialised all your watchers and you want to start
716	handling events.	735	handling events. It will ask the operating system for any new events, call
		736	the watcher callbacks, an then repeat the whole process indefinitely: This
		737	is why event loops are called I<loops>.
717		738
718	If the flags argument is specified as C<0>, it will not return until	739	If the flags argument is specified as C<0>, it will keep handling events
719	either no event watchers are active anymore or C<ev_unloop> was called.	740	until either no event watchers are active anymore or C<ev_break> was
		741	called.
720		742
721	Please note that an explicit C<ev_unloop> is usually better than	743	Please note that an explicit C<ev_break> is usually better than
722	relying on all watchers to be stopped when deciding when a program has	744	relying on all watchers to be stopped when deciding when a program has
723	finished (especially in interactive programs), but having a program	745	finished (especially in interactive programs), but having a program
724	that automatically loops as long as it has to and no longer by virtue	746	that automatically loops as long as it has to and no longer by virtue
725	of relying on its watchers stopping correctly, that is truly a thing of	747	of relying on its watchers stopping correctly, that is truly a thing of
726	beauty.	748	beauty.
727		749
728	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	750	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
729	those events and any already outstanding ones, but will not block your	751	those events and any already outstanding ones, but will not wait and
730	process in case there are no events and will return after one iteration of	752	block your process in case there are no events and will return after one
731	the loop.	753	iteration of the loop. This is sometimes useful to poll and handle new
		754	events while doing lengthy calculations, to keep the program responsive.
732		755
733	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	756	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
734	necessary) and will handle those and any already outstanding ones. It	757	necessary) and will handle those and any already outstanding ones. It
735	will block your process until at least one new event arrives (which could	758	will block your process until at least one new event arrives (which could
736	be an event internal to libev itself, so there is no guarantee that a	759	be an event internal to libev itself, so there is no guarantee that a
737	user-registered callback will be called), and will return after one	760	user-registered callback will be called), and will return after one
738	iteration of the loop.	761	iteration of the loop.
739		762
740	This is useful if you are waiting for some external event in conjunction	763	This is useful if you are waiting for some external event in conjunction
741	with something not expressible using other libev watchers (i.e. "roll your	764	with something not expressible using other libev watchers (i.e. "roll your
742	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	765	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
743	usually a better approach for this kind of thing.	766	usually a better approach for this kind of thing.
744		767
745	Here are the gory details of what C<ev_loop> does:	768	Here are the gory details of what C<ev_run> does:
746		769
		770	- Increment loop depth.
		771	- Reset the ev_break status.
747	- Before the first iteration, call any pending watchers.	772	- Before the first iteration, call any pending watchers.
		773	LOOP:
748	* If EVFLAG_FORKCHECK was used, check for a fork.	774	- If EVFLAG_FORKCHECK was used, check for a fork.
749	- If a fork was detected (by any means), queue and call all fork watchers.	775	- If a fork was detected (by any means), queue and call all fork watchers.
750	- Queue and call all prepare watchers.	776	- Queue and call all prepare watchers.
		777	- If ev_break was called, goto FINISH.
751	- If we have been forked, detach and recreate the kernel state	778	- If we have been forked, detach and recreate the kernel state
752	as to not disturb the other process.	779	as to not disturb the other process.
753	- Update the kernel state with all outstanding changes.	780	- Update the kernel state with all outstanding changes.
754	- Update the "event loop time" (ev_now ()).	781	- Update the "event loop time" (ev_now ()).
755	- Calculate for how long to sleep or block, if at all	782	- Calculate for how long to sleep or block, if at all
756	(active idle watchers, EVLOOP_NONBLOCK or not having	783	(active idle watchers, EVRUN_NOWAIT or not having
757	any active watchers at all will result in not sleeping).	784	any active watchers at all will result in not sleeping).
758	- Sleep if the I/O and timer collect interval say so.	785	- Sleep if the I/O and timer collect interval say so.
		786	- Increment loop iteration counter.
759	- Block the process, waiting for any events.	787	- Block the process, waiting for any events.
760	- Queue all outstanding I/O (fd) events.	788	- Queue all outstanding I/O (fd) events.
761	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	789	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
762	- Queue all expired timers.	790	- Queue all expired timers.
763	- Queue all expired periodics.	791	- Queue all expired periodics.
764	- Unless any events are pending now, queue all idle watchers.	792	- Queue all idle watchers with priority higher than that of pending events.
765	- Queue all check watchers.	793	- Queue all check watchers.
766	- Call all queued watchers in reverse order (i.e. check watchers first).	794	- Call all queued watchers in reverse order (i.e. check watchers first).
767	Signals and child watchers are implemented as I/O watchers, and will	795	Signals and child watchers are implemented as I/O watchers, and will
768	be handled here by queueing them when their watcher gets executed.	796	be handled here by queueing them when their watcher gets executed.
769	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	797	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
770	were used, or there are no active watchers, return, otherwise	798	were used, or there are no active watchers, goto FINISH, otherwise
771	continue with step *.	799	continue with step LOOP.
		800	FINISH:
		801	- Reset the ev_break status iff it was EVBREAK_ONE.
		802	- Decrement the loop depth.
		803	- Return.
772		804
773	Example: Queue some jobs and then loop until no events are outstanding	805	Example: Queue some jobs and then loop until no events are outstanding
774	anymore.	806	anymore.
775		807
776	... queue jobs here, make sure they register event watchers as long	808	... queue jobs here, make sure they register event watchers as long
777	... as they still have work to do (even an idle watcher will do..)	809	... as they still have work to do (even an idle watcher will do..)
778	ev_loop (my_loop, 0);	810	ev_run (my_loop, 0);
779	... jobs done or somebody called unloop. yeah!	811	... jobs done or somebody called unloop. yeah!
780		812
781	=item ev_unloop (loop, how)	813	=item ev_break (loop, how)
782		814
783	Can be used to make a call to C<ev_loop> return early (but only after it	815	Can be used to make a call to C<ev_run> return early (but only after it
784	has processed all outstanding events). The C<how> argument must be either	816	has processed all outstanding events). The C<how> argument must be either
785	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	817	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
786	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	818	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
787		819
788	This "unloop state" will be cleared when entering C<ev_loop> again.	820	This "unloop state" will be cleared when entering C<ev_run> again.
789		821
790	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	822	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
791		823
792	=item ev_ref (loop)	824	=item ev_ref (loop)
793		825
794	=item ev_unref (loop)	826	=item ev_unref (loop)
795		827
796	Ref/unref can be used to add or remove a reference count on the event	828	Ref/unref can be used to add or remove a reference count on the event
797	loop: Every watcher keeps one reference, and as long as the reference	829	loop: Every watcher keeps one reference, and as long as the reference
798	count is nonzero, C<ev_loop> will not return on its own.	830	count is nonzero, C<ev_run> will not return on its own.
799		831
800	This is useful when you have a watcher that you never intend to	832	This is useful when you have a watcher that you never intend to
801	unregister, but that nevertheless should not keep C<ev_loop> from	833	unregister, but that nevertheless should not keep C<ev_run> from
802	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>	834	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
803	before stopping it.	835	before stopping it.
804		836
805	As an example, libev itself uses this for its internal signal pipe: It	837	As an example, libev itself uses this for its internal signal pipe: It
806	is not visible to the libev user and should not keep C<ev_loop> from	838	is not visible to the libev user and should not keep C<ev_run> from
807	exiting if no event watchers registered by it are active. It is also an	839	exiting if no event watchers registered by it are active. It is also an
808	excellent way to do this for generic recurring timers or from within	840	excellent way to do this for generic recurring timers or from within
809	third-party libraries. Just remember to I<unref after start> and I<ref	841	third-party libraries. Just remember to I<unref after start> and I<ref
810	before stop> (but only if the watcher wasn't active before, or was active	842	before stop> (but only if the watcher wasn't active before, or was active
811	before, respectively. Note also that libev might stop watchers itself	843	before, respectively. Note also that libev might stop watchers itself
812	(e.g. non-repeating timers) in which case you have to C<ev_ref>	844	(e.g. non-repeating timers) in which case you have to C<ev_ref>
813	in the callback).	845	in the callback).
814		846
815	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	847	Example: Create a signal watcher, but keep it from keeping C<ev_run>
816	running when nothing else is active.	848	running when nothing else is active.
817		849
818	ev_signal exitsig;	850	ev_signal exitsig;
819	ev_signal_init (&exitsig, sig_cb, SIGINT);	851	ev_signal_init (&exitsig, sig_cb, SIGINT);
820	ev_signal_start (loop, &exitsig);	852	ev_signal_start (loop, &exitsig);
…		…
865	usually doesn't make much sense to set it to a lower value than C<0.01>,	897	usually doesn't make much sense to set it to a lower value than C<0.01>,
866	as this approaches the timing granularity of most systems. Note that if	898	as this approaches the timing granularity of most systems. Note that if
867	you do transactions with the outside world and you can't increase the	899	you do transactions with the outside world and you can't increase the
868	parallelity, then this setting will limit your transaction rate (if you	900	parallelity, then this setting will limit your transaction rate (if you
869	need to poll once per transaction and the I/O collect interval is 0.01,	901	need to poll once per transaction and the I/O collect interval is 0.01,
870	then you can't do more than 100 transations per second).	902	then you can't do more than 100 transactions per second).
871		903
872	Setting the I<timeout collect interval> can improve the opportunity for	904	Setting the I<timeout collect interval> can improve the opportunity for
873	saving power, as the program will "bundle" timer callback invocations that	905	saving power, as the program will "bundle" timer callback invocations that
874	are "near" in time together, by delaying some, thus reducing the number of	906	are "near" in time together, by delaying some, thus reducing the number of
875	times the process sleeps and wakes up again. Another useful technique to	907	times the process sleeps and wakes up again. Another useful technique to
…		…
883	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	915	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
884		916
885	=item ev_invoke_pending (loop)	917	=item ev_invoke_pending (loop)
886		918
887	This call will simply invoke all pending watchers while resetting their	919	This call will simply invoke all pending watchers while resetting their
888	pending state. Normally, C<ev_loop> does this automatically when required,	920	pending state. Normally, C<ev_run> does this automatically when required,
889	but when overriding the invoke callback this call comes handy.	921	but when overriding the invoke callback this call comes handy. This
		922	function can be invoked from a watcher - this can be useful for example
		923	when you want to do some lengthy calculation and want to pass further
		924	event handling to another thread (you still have to make sure only one
		925	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
890		926
891	=item int ev_pending_count (loop)	927	=item int ev_pending_count (loop)
892		928
893	Returns the number of pending watchers - zero indicates that no watchers	929	Returns the number of pending watchers - zero indicates that no watchers
894	are pending.	930	are pending.
895		931
896	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	932	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
897		933
898	This overrides the invoke pending functionality of the loop: Instead of	934	This overrides the invoke pending functionality of the loop: Instead of
899	invoking all pending watchers when there are any, C<ev_loop> will call	935	invoking all pending watchers when there are any, C<ev_run> will call
900	this callback instead. This is useful, for example, when you want to	936	this callback instead. This is useful, for example, when you want to
901	invoke the actual watchers inside another context (another thread etc.).	937	invoke the actual watchers inside another context (another thread etc.).
902		938
903	If you want to reset the callback, use C<ev_invoke_pending> as new	939	If you want to reset the callback, use C<ev_invoke_pending> as new
904	callback.	940	callback.
…		…
907		943
908	Sometimes you want to share the same loop between multiple threads. This	944	Sometimes you want to share the same loop between multiple threads. This
909	can be done relatively simply by putting mutex_lock/unlock calls around	945	can be done relatively simply by putting mutex_lock/unlock calls around
910	each call to a libev function.	946	each call to a libev function.
911		947
912	However, C<ev_loop> can run an indefinite time, so it is not feasible to	948	However, C<ev_run> can run an indefinite time, so it is not feasible
913	wait for it to return. One way around this is to wake up the loop via	949	to wait for it to return. One way around this is to wake up the event
914	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	950	loop via C<ev_break> and C<av_async_send>, another way is to set these
915	and I<acquire> callbacks on the loop.	951	I<release> and I<acquire> callbacks on the loop.
916		952
917	When set, then C<release> will be called just before the thread is	953	When set, then C<release> will be called just before the thread is
918	suspended waiting for new events, and C<acquire> is called just	954	suspended waiting for new events, and C<acquire> is called just
919	afterwards.	955	afterwards.
920		956
…		…
923		959
924	While event loop modifications are allowed between invocations of	960	While event loop modifications are allowed between invocations of
925	C<release> and C<acquire> (that's their only purpose after all), no	961	C<release> and C<acquire> (that's their only purpose after all), no
926	modifications done will affect the event loop, i.e. adding watchers will	962	modifications done will affect the event loop, i.e. adding watchers will
927	have no effect on the set of file descriptors being watched, or the time	963	have no effect on the set of file descriptors being watched, or the time
928	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	964	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
929	to take note of any changes you made.	965	to take note of any changes you made.
930		966
931	In theory, threads executing C<ev_loop> will be async-cancel safe between	967	In theory, threads executing C<ev_run> will be async-cancel safe between
932	invocations of C<release> and C<acquire>.	968	invocations of C<release> and C<acquire>.
933		969
934	See also the locking example in the C<THREADS> section later in this	970	See also the locking example in the C<THREADS> section later in this
935	document.	971	document.
936		972
…		…
945	These two functions can be used to associate arbitrary data with a loop,	981	These two functions can be used to associate arbitrary data with a loop,
946	and are intended solely for the C<invoke_pending_cb>, C<release> and	982	and are intended solely for the C<invoke_pending_cb>, C<release> and
947	C<acquire> callbacks described above, but of course can be (ab-)used for	983	C<acquire> callbacks described above, but of course can be (ab-)used for
948	any other purpose as well.	984	any other purpose as well.
949		985
950	=item ev_loop_verify (loop)	986	=item ev_verify (loop)
951		987
952	This function only does something when C<EV_VERIFY> support has been	988	This function only does something when C<EV_VERIFY> support has been
953	compiled in, which is the default for non-minimal builds. It tries to go	989	compiled in, which is the default for non-minimal builds. It tries to go
954	through all internal structures and checks them for validity. If anything	990	through all internal structures and checks them for validity. If anything
955	is found to be inconsistent, it will print an error message to standard	991	is found to be inconsistent, it will print an error message to standard
…		…
966		1002
967	In the following description, uppercase C<TYPE> in names stands for the	1003	In the following description, uppercase C<TYPE> in names stands for the
968	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1004	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
969	watchers and C<ev_io_start> for I/O watchers.	1005	watchers and C<ev_io_start> for I/O watchers.
970		1006
971	A watcher is a structure that you create and register to record your	1007	A watcher is an opaque structure that you allocate and register to record
972	interest in some event. For instance, if you want to wait for STDIN to	1008	your interest in some event. To make a concrete example, imagine you want
973	become readable, you would create an C<ev_io> watcher for that:	1009	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1010	for that:
974		1011
975	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1012	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
976	{	1013	{
977	ev_io_stop (w);	1014	ev_io_stop (w);
978	ev_unloop (loop, EVUNLOOP_ALL);	1015	ev_break (loop, EVBREAK_ALL);
979	}	1016	}
980		1017
981	struct ev_loop *loop = ev_default_loop (0);	1018	struct ev_loop *loop = ev_default_loop (0);
982		1019
983	ev_io stdin_watcher;	1020	ev_io stdin_watcher;
984		1021
985	ev_init (&stdin_watcher, my_cb);	1022	ev_init (&stdin_watcher, my_cb);
986	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1023	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
987	ev_io_start (loop, &stdin_watcher);	1024	ev_io_start (loop, &stdin_watcher);
988		1025
989	ev_loop (loop, 0);	1026	ev_run (loop, 0);
990		1027
991	As you can see, you are responsible for allocating the memory for your	1028	As you can see, you are responsible for allocating the memory for your
992	watcher structures (and it is I<usually> a bad idea to do this on the	1029	watcher structures (and it is I<usually> a bad idea to do this on the
993	stack).	1030	stack).
994		1031
995	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1032	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
996	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1033	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
997		1034
998	Each watcher structure must be initialised by a call to C<ev_init	1035	Each watcher structure must be initialised by a call to C<ev_init (watcher
999	(watcher *, callback)>, which expects a callback to be provided. This	1036	*, callback)>, which expects a callback to be provided. This callback is
1000	callback gets invoked each time the event occurs (or, in the case of I/O	1037	invoked each time the event occurs (or, in the case of I/O watchers, each
1001	watchers, each time the event loop detects that the file descriptor given	1038	time the event loop detects that the file descriptor given is readable
1002	is readable and/or writable).	1039	and/or writable).
1003		1040
1004	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1041	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1005	macro to configure it, with arguments specific to the watcher type. There	1042	macro to configure it, with arguments specific to the watcher type. There
1006	is also a macro to combine initialisation and setting in one call: C<<	1043	is also a macro to combine initialisation and setting in one call: C<<
1007	ev_TYPE_init (watcher *, callback, ...) >>.	1044	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1030	=item C<EV_WRITE>	1067	=item C<EV_WRITE>
1031		1068
1032	The file descriptor in the C<ev_io> watcher has become readable and/or	1069	The file descriptor in the C<ev_io> watcher has become readable and/or
1033	writable.	1070	writable.
1034		1071
1035	=item C<EV_TIMEOUT>	1072	=item C<EV_TIMER>
1036		1073
1037	The C<ev_timer> watcher has timed out.	1074	The C<ev_timer> watcher has timed out.
1038		1075
1039	=item C<EV_PERIODIC>	1076	=item C<EV_PERIODIC>
1040		1077
…		…
1058		1095
1059	=item C<EV_PREPARE>	1096	=item C<EV_PREPARE>
1060		1097
1061	=item C<EV_CHECK>	1098	=item C<EV_CHECK>
1062		1099
1063	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1100	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1064	to gather new events, and all C<ev_check> watchers are invoked just after	1101	to gather new events, and all C<ev_check> watchers are invoked just after
1065	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1102	C<ev_run> has gathered them, but before it invokes any callbacks for any
1066	received events. Callbacks of both watcher types can start and stop as	1103	received events. Callbacks of both watcher types can start and stop as
1067	many watchers as they want, and all of them will be taken into account	1104	many watchers as they want, and all of them will be taken into account
1068	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1105	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1069	C<ev_loop> from blocking).	1106	C<ev_run> from blocking).
1070		1107
1071	=item C<EV_EMBED>	1108	=item C<EV_EMBED>
1072		1109
1073	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1110	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1074		1111
…		…
1102	example it might indicate that a fd is readable or writable, and if your	1139	example it might indicate that a fd is readable or writable, and if your
1103	callbacks is well-written it can just attempt the operation and cope with	1140	callbacks is well-written it can just attempt the operation and cope with
1104	the error from read() or write(). This will not work in multi-threaded	1141	the error from read() or write(). This will not work in multi-threaded
1105	programs, though, as the fd could already be closed and reused for another	1142	programs, though, as the fd could already be closed and reused for another
1106	thing, so beware.	1143	thing, so beware.
		1144
		1145	=back
		1146
		1147	=head2 WATCHER STATES
		1148
		1149	There are various watcher states mentioned throughout this manual -
		1150	active, pending and so on. In this section these states and the rules to
		1151	transition between them will be described in more detail - and while these
		1152	rules might look complicated, they usually do "the right thing".
		1153
		1154	=over 4
		1155
		1156	=item initialiased
		1157
		1158	Before a watcher can be registered with the event looop it has to be
		1159	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1160	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1161
		1162	In this state it is simply some block of memory that is suitable for use
		1163	in an event loop. It can be moved around, freed, reused etc. at will.
		1164
		1165	=item started/running/active
		1166
		1167	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1168	property of the event loop, and is actively waiting for events. While in
		1169	this state it cannot be accessed (except in a few documented ways), moved,
		1170	freed or anything else - the only legal thing is to keep a pointer to it,
		1171	and call libev functions on it that are documented to work on active watchers.
		1172
		1173	=item pending
		1174
		1175	If a watcher is active and libev determines that an event it is interested
		1176	in has occurred (such as a timer expiring), it will become pending. It will
		1177	stay in this pending state until either it is stopped or its callback is
		1178	about to be invoked, so it is not normally pending inside the watcher
		1179	callback.
		1180
		1181	The watcher might or might not be active while it is pending (for example,
		1182	an expired non-repeating timer can be pending but no longer active). If it
		1183	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1184	but it is still property of the event loop at this time, so cannot be
		1185	moved, freed or reused. And if it is active the rules described in the
		1186	previous item still apply.
		1187
		1188	It is also possible to feed an event on a watcher that is not active (e.g.
		1189	via C<ev_feed_event>), in which case it becomes pending without being
		1190	active.
		1191
		1192	=item stopped
		1193
		1194	A watcher can be stopped implicitly by libev (in which case it might still
		1195	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1196	latter will clear any pending state the watcher might be in, regardless
		1197	of whether it was active or not, so stopping a watcher explicitly before
		1198	freeing it is often a good idea.
		1199
		1200	While stopped (and not pending) the watcher is essentially in the
		1201	initialised state, that is it can be reused, moved, modified in any way
		1202	you wish.
1107		1203
1108	=back	1204	=back
1109		1205
1110	=head2 GENERIC WATCHER FUNCTIONS	1206	=head2 GENERIC WATCHER FUNCTIONS
1111		1207
…		…
1373		1469
1374	For example, to emulate how many other event libraries handle priorities,	1470	For example, to emulate how many other event libraries handle priorities,
1375	you can associate an C<ev_idle> watcher to each such watcher, and in	1471	you can associate an C<ev_idle> watcher to each such watcher, and in
1376	the normal watcher callback, you just start the idle watcher. The real	1472	the normal watcher callback, you just start the idle watcher. The real
1377	processing is done in the idle watcher callback. This causes libev to	1473	processing is done in the idle watcher callback. This causes libev to
1378	continously poll and process kernel event data for the watcher, but when	1474	continuously poll and process kernel event data for the watcher, but when
1379	the lock-out case is known to be rare (which in turn is rare :), this is	1475	the lock-out case is known to be rare (which in turn is rare :), this is
1380	workable.	1476	workable.
1381		1477
1382	Usually, however, the lock-out model implemented that way will perform	1478	Usually, however, the lock-out model implemented that way will perform
1383	miserably under the type of load it was designed to handle. In that case,	1479	miserably under the type of load it was designed to handle. In that case,
…		…
1397	{	1493	{
1398	// stop the I/O watcher, we received the event, but	1494	// stop the I/O watcher, we received the event, but
1399	// are not yet ready to handle it.	1495	// are not yet ready to handle it.
1400	ev_io_stop (EV_A_ w);	1496	ev_io_stop (EV_A_ w);
1401		1497
1402	// start the idle watcher to ahndle the actual event.	1498	// start the idle watcher to handle the actual event.
1403	// it will not be executed as long as other watchers	1499	// it will not be executed as long as other watchers
1404	// with the default priority are receiving events.	1500	// with the default priority are receiving events.
1405	ev_idle_start (EV_A_ &idle);	1501	ev_idle_start (EV_A_ &idle);
1406	}	1502	}
1407		1503
…		…
1461		1557
1462	If you cannot use non-blocking mode, then force the use of a	1558	If you cannot use non-blocking mode, then force the use of a
1463	known-to-be-good backend (at the time of this writing, this includes only	1559	known-to-be-good backend (at the time of this writing, this includes only
1464	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1560	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1465	descriptors for which non-blocking operation makes no sense (such as	1561	descriptors for which non-blocking operation makes no sense (such as
1466	files) - libev doesn't guarentee any specific behaviour in that case.	1562	files) - libev doesn't guarantee any specific behaviour in that case.
1467		1563
1468	Another thing you have to watch out for is that it is quite easy to	1564	Another thing you have to watch out for is that it is quite easy to
1469	receive "spurious" readiness notifications, that is your callback might	1565	receive "spurious" readiness notifications, that is your callback might
1470	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1566	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1471	because there is no data. Not only are some backends known to create a	1567	because there is no data. Not only are some backends known to create a
…		…
1536		1632
1537	So when you encounter spurious, unexplained daemon exits, make sure you	1633	So when you encounter spurious, unexplained daemon exits, make sure you
1538	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1634	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1539	somewhere, as that would have given you a big clue).	1635	somewhere, as that would have given you a big clue).
1540		1636
		1637	=head3 The special problem of accept()ing when you can't
		1638
		1639	Many implementations of the POSIX C<accept> function (for example,
		1640	found in post-2004 Linux) have the peculiar behaviour of not removing a
		1641	connection from the pending queue in all error cases.
		1642
		1643	For example, larger servers often run out of file descriptors (because
		1644	of resource limits), causing C<accept> to fail with C<ENFILE> but not
		1645	rejecting the connection, leading to libev signalling readiness on
		1646	the next iteration again (the connection still exists after all), and
		1647	typically causing the program to loop at 100% CPU usage.
		1648
		1649	Unfortunately, the set of errors that cause this issue differs between
		1650	operating systems, there is usually little the app can do to remedy the
		1651	situation, and no known thread-safe method of removing the connection to
		1652	cope with overload is known (to me).
		1653
		1654	One of the easiest ways to handle this situation is to just ignore it
		1655	- when the program encounters an overload, it will just loop until the
		1656	situation is over. While this is a form of busy waiting, no OS offers an
		1657	event-based way to handle this situation, so it's the best one can do.
		1658
		1659	A better way to handle the situation is to log any errors other than
		1660	C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
		1661	messages, and continue as usual, which at least gives the user an idea of
		1662	what could be wrong ("raise the ulimit!"). For extra points one could stop
		1663	the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
		1664	usage.
		1665
		1666	If your program is single-threaded, then you could also keep a dummy file
		1667	descriptor for overload situations (e.g. by opening F</dev/null>), and
		1668	when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
		1669	close that fd, and create a new dummy fd. This will gracefully refuse
		1670	clients under typical overload conditions.
		1671
		1672	The last way to handle it is to simply log the error and C<exit>, as
		1673	is often done with C<malloc> failures, but this results in an easy
		1674	opportunity for a DoS attack.
1541		1675
1542	=head3 Watcher-Specific Functions	1676	=head3 Watcher-Specific Functions
1543		1677
1544	=over 4	1678	=over 4
1545		1679
…		…
1577	...	1711	...
1578	struct ev_loop *loop = ev_default_init (0);	1712	struct ev_loop *loop = ev_default_init (0);
1579	ev_io stdin_readable;	1713	ev_io stdin_readable;
1580	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1714	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1581	ev_io_start (loop, &stdin_readable);	1715	ev_io_start (loop, &stdin_readable);
1582	ev_loop (loop, 0);	1716	ev_run (loop, 0);
1583		1717
1584		1718
1585	=head2 C<ev_timer> - relative and optionally repeating timeouts	1719	=head2 C<ev_timer> - relative and optionally repeating timeouts
1586		1720
1587	Timer watchers are simple relative timers that generate an event after a	1721	Timer watchers are simple relative timers that generate an event after a
…		…
1596	The callback is guaranteed to be invoked only I<after> its timeout has	1730	The callback is guaranteed to be invoked only I<after> its timeout has
1597	passed (not I<at>, so on systems with very low-resolution clocks this	1731	passed (not I<at>, so on systems with very low-resolution clocks this
1598	might introduce a small delay). If multiple timers become ready during the	1732	might introduce a small delay). If multiple timers become ready during the
1599	same loop iteration then the ones with earlier time-out values are invoked	1733	same loop iteration then the ones with earlier time-out values are invoked
1600	before ones of the same priority with later time-out values (but this is	1734	before ones of the same priority with later time-out values (but this is
1601	no longer true when a callback calls C<ev_loop> recursively).	1735	no longer true when a callback calls C<ev_run> recursively).
1602		1736
1603	=head3 Be smart about timeouts	1737	=head3 Be smart about timeouts
1604		1738
1605	Many real-world problems involve some kind of timeout, usually for error	1739	Many real-world problems involve some kind of timeout, usually for error
1606	recovery. A typical example is an HTTP request - if the other side hangs,	1740	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1692	ev_tstamp timeout = last_activity + 60.;	1826	ev_tstamp timeout = last_activity + 60.;
1693		1827
1694	// if last_activity + 60. is older than now, we did time out	1828	// if last_activity + 60. is older than now, we did time out
1695	if (timeout < now)	1829	if (timeout < now)
1696	{	1830	{
1697	// timeout occured, take action	1831	// timeout occurred, take action
1698	}	1832	}
1699	else	1833	else
1700	{	1834	{
1701	// callback was invoked, but there was some activity, re-arm	1835	// callback was invoked, but there was some activity, re-arm
1702	// the watcher to fire in last_activity + 60, which is	1836	// the watcher to fire in last_activity + 60, which is
…		…
1724	to the current time (meaning we just have some activity :), then call the	1858	to the current time (meaning we just have some activity :), then call the
1725	callback, which will "do the right thing" and start the timer:	1859	callback, which will "do the right thing" and start the timer:
1726		1860
1727	ev_init (timer, callback);	1861	ev_init (timer, callback);
1728	last_activity = ev_now (loop);	1862	last_activity = ev_now (loop);
1729	callback (loop, timer, EV_TIMEOUT);	1863	callback (loop, timer, EV_TIMER);
1730		1864
1731	And when there is some activity, simply store the current time in	1865	And when there is some activity, simply store the current time in
1732	C<last_activity>, no libev calls at all:	1866	C<last_activity>, no libev calls at all:
1733		1867
1734	last_actiivty = ev_now (loop);	1868	last_activity = ev_now (loop);
1735		1869
1736	This technique is slightly more complex, but in most cases where the	1870	This technique is slightly more complex, but in most cases where the
1737	time-out is unlikely to be triggered, much more efficient.	1871	time-out is unlikely to be triggered, much more efficient.
1738		1872
1739	Changing the timeout is trivial as well (if it isn't hard-coded in the	1873	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1777		1911
1778	=head3 The special problem of time updates	1912	=head3 The special problem of time updates
1779		1913
1780	Establishing the current time is a costly operation (it usually takes at	1914	Establishing the current time is a costly operation (it usually takes at
1781	least two system calls): EV therefore updates its idea of the current	1915	least two system calls): EV therefore updates its idea of the current
1782	time only before and after C<ev_loop> collects new events, which causes a	1916	time only before and after C<ev_run> collects new events, which causes a
1783	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1917	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1784	lots of events in one iteration.	1918	lots of events in one iteration.
1785		1919
1786	The relative timeouts are calculated relative to the C<ev_now ()>	1920	The relative timeouts are calculated relative to the C<ev_now ()>
1787	time. This is usually the right thing as this timestamp refers to the time	1921	time. This is usually the right thing as this timestamp refers to the time
…		…
1865	Returns the remaining time until a timer fires. If the timer is active,	1999	Returns the remaining time until a timer fires. If the timer is active,
1866	then this time is relative to the current event loop time, otherwise it's	2000	then this time is relative to the current event loop time, otherwise it's
1867	the timeout value currently configured.	2001	the timeout value currently configured.
1868		2002
1869	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns	2003	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
1870	C<5>. When the timer is started and one second passes, C<ev_timer_remain>	2004	C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
1871	will return C<4>. When the timer expires and is restarted, it will return	2005	will return C<4>. When the timer expires and is restarted, it will return
1872	roughly C<7> (likely slightly less as callback invocation takes some time,	2006	roughly C<7> (likely slightly less as callback invocation takes some time,
1873	too), and so on.	2007	too), and so on.
1874		2008
1875	=item ev_tstamp repeat [read-write]	2009	=item ev_tstamp repeat [read-write]
…		…
1904	}	2038	}
1905		2039
1906	ev_timer mytimer;	2040	ev_timer mytimer;
1907	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2041	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1908	ev_timer_again (&mytimer); /* start timer */	2042	ev_timer_again (&mytimer); /* start timer */
1909	ev_loop (loop, 0);	2043	ev_run (loop, 0);
1910		2044
1911	// and in some piece of code that gets executed on any "activity":	2045	// and in some piece of code that gets executed on any "activity":
1912	// reset the timeout to start ticking again at 10 seconds	2046	// reset the timeout to start ticking again at 10 seconds
1913	ev_timer_again (&mytimer);	2047	ev_timer_again (&mytimer);
1914		2048
…		…
1940		2074
1941	As with timers, the callback is guaranteed to be invoked only when the	2075	As with timers, the callback is guaranteed to be invoked only when the
1942	point in time where it is supposed to trigger has passed. If multiple	2076	point in time where it is supposed to trigger has passed. If multiple
1943	timers become ready during the same loop iteration then the ones with	2077	timers become ready during the same loop iteration then the ones with
1944	earlier time-out values are invoked before ones with later time-out values	2078	earlier time-out values are invoked before ones with later time-out values
1945	(but this is no longer true when a callback calls C<ev_loop> recursively).	2079	(but this is no longer true when a callback calls C<ev_run> recursively).
1946		2080
1947	=head3 Watcher-Specific Functions and Data Members	2081	=head3 Watcher-Specific Functions and Data Members
1948		2082
1949	=over 4	2083	=over 4
1950		2084
…		…
2078	Example: Call a callback every hour, or, more precisely, whenever the	2212	Example: Call a callback every hour, or, more precisely, whenever the
2079	system time is divisible by 3600. The callback invocation times have	2213	system time is divisible by 3600. The callback invocation times have
2080	potentially a lot of jitter, but good long-term stability.	2214	potentially a lot of jitter, but good long-term stability.
2081		2215
2082	static void	2216	static void
2083	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2217	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
2084	{	2218	{
2085	... its now a full hour (UTC, or TAI or whatever your clock follows)	2219	... its now a full hour (UTC, or TAI or whatever your clock follows)
2086	}	2220	}
2087		2221
2088	ev_periodic hourly_tick;	2222	ev_periodic hourly_tick;
…		…
2160	In current versions of libev, the signal will not be blocked indefinitely	2294	In current versions of libev, the signal will not be blocked indefinitely
2161	unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces	2295	unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
2162	the window of opportunity for problems, it will not go away, as libev	2296	the window of opportunity for problems, it will not go away, as libev
2163	I<has> to modify the signal mask, at least temporarily.	2297	I<has> to modify the signal mask, at least temporarily.
2164		2298
2165	So I can't stress this enough I<if you do not reset your signal mask	2299	So I can't stress this enough: I<If you do not reset your signal mask when
2166	when you expect it to be empty, you have a race condition in your	2300	you expect it to be empty, you have a race condition in your code>. This
2167	program>. This is not a libev-specific thing, this is true for most event	2301	is not a libev-specific thing, this is true for most event libraries.
2168	libraries.
2169		2302
2170	=head3 Watcher-Specific Functions and Data Members	2303	=head3 Watcher-Specific Functions and Data Members
2171		2304
2172	=over 4	2305	=over 4
2173		2306
…		…
2189	Example: Try to exit cleanly on SIGINT.	2322	Example: Try to exit cleanly on SIGINT.
2190		2323
2191	static void	2324	static void
2192	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2325	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2193	{	2326	{
2194	ev_unloop (loop, EVUNLOOP_ALL);	2327	ev_break (loop, EVBREAK_ALL);
2195	}	2328	}
2196		2329
2197	ev_signal signal_watcher;	2330	ev_signal signal_watcher;
2198	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2331	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2199	ev_signal_start (loop, &signal_watcher);	2332	ev_signal_start (loop, &signal_watcher);
…		…
2585		2718
2586	Prepare and check watchers are usually (but not always) used in pairs:	2719	Prepare and check watchers are usually (but not always) used in pairs:
2587	prepare watchers get invoked before the process blocks and check watchers	2720	prepare watchers get invoked before the process blocks and check watchers
2588	afterwards.	2721	afterwards.
2589		2722
2590	You I<must not> call C<ev_loop> or similar functions that enter	2723	You I<must not> call C<ev_run> or similar functions that enter
2591	the current event loop from either C<ev_prepare> or C<ev_check>	2724	the current event loop from either C<ev_prepare> or C<ev_check>
2592	watchers. Other loops than the current one are fine, however. The	2725	watchers. Other loops than the current one are fine, however. The
2593	rationale behind this is that you do not need to check for recursion in	2726	rationale behind this is that you do not need to check for recursion in
2594	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2727	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2595	C<ev_check> so if you have one watcher of each kind they will always be	2728	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2763		2896
2764	if (timeout >= 0)	2897	if (timeout >= 0)
2765	// create/start timer	2898	// create/start timer
2766		2899
2767	// poll	2900	// poll
2768	ev_loop (EV_A_ 0);	2901	ev_run (EV_A_ 0);
2769		2902
2770	// stop timer again	2903	// stop timer again
2771	if (timeout >= 0)	2904	if (timeout >= 0)
2772	ev_timer_stop (EV_A_ &to);	2905	ev_timer_stop (EV_A_ &to);
2773		2906
…		…
2851	if you do not want that, you need to temporarily stop the embed watcher).	2984	if you do not want that, you need to temporarily stop the embed watcher).
2852		2985
2853	=item ev_embed_sweep (loop, ev_embed *)	2986	=item ev_embed_sweep (loop, ev_embed *)
2854		2987
2855	Make a single, non-blocking sweep over the embedded loop. This works	2988	Make a single, non-blocking sweep over the embedded loop. This works
2856	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2989	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2857	appropriate way for embedded loops.	2990	appropriate way for embedded loops.
2858		2991
2859	=item struct ev_loop *other [read-only]	2992	=item struct ev_loop *other [read-only]
2860		2993
2861	The embedded event loop.	2994	The embedded event loop.
…		…
2921	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3054	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2922	handlers will be invoked, too, of course.	3055	handlers will be invoked, too, of course.
2923		3056
2924	=head3 The special problem of life after fork - how is it possible?	3057	=head3 The special problem of life after fork - how is it possible?
2925		3058
2926	Most uses of C<fork()> consist of forking, then some simple calls to ste	3059	Most uses of C<fork()> consist of forking, then some simple calls to set
2927	up/change the process environment, followed by a call to C<exec()>. This	3060	up/change the process environment, followed by a call to C<exec()>. This
2928	sequence should be handled by libev without any problems.	3061	sequence should be handled by libev without any problems.
2929		3062
2930	This changes when the application actually wants to do event handling	3063	This changes when the application actually wants to do event handling
2931	in the child, or both parent in child, in effect "continuing" after the	3064	in the child, or both parent in child, in effect "continuing" after the
…		…
2947	disadvantage of having to use multiple event loops (which do not support	3080	disadvantage of having to use multiple event loops (which do not support
2948	signal watchers).	3081	signal watchers).
2949		3082
2950	When this is not possible, or you want to use the default loop for	3083	When this is not possible, or you want to use the default loop for
2951	other reasons, then in the process that wants to start "fresh", call	3084	other reasons, then in the process that wants to start "fresh", call
2952	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3085	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2953	the default loop will "orphan" (not stop) all registered watchers, so you	3086	Destroying the default loop will "orphan" (not stop) all registered
2954	have to be careful not to execute code that modifies those watchers. Note	3087	watchers, so you have to be careful not to execute code that modifies
2955	also that in that case, you have to re-register any signal watchers.	3088	those watchers. Note also that in that case, you have to re-register any
		3089	signal watchers.
2956		3090
2957	=head3 Watcher-Specific Functions and Data Members	3091	=head3 Watcher-Specific Functions and Data Members
2958		3092
2959	=over 4	3093	=over 4
2960		3094
…		…
2965	believe me.	3099	believe me.
2966		3100
2967	=back	3101	=back
2968		3102
2969		3103
2970	=head2 C<ev_async> - how to wake up another event loop	3104	=head2 C<ev_async> - how to wake up an event loop
2971		3105
2972	In general, you cannot use an C<ev_loop> from multiple threads or other	3106	In general, you cannot use an C<ev_run> from multiple threads or other
2973	asynchronous sources such as signal handlers (as opposed to multiple event	3107	asynchronous sources such as signal handlers (as opposed to multiple event
2974	loops - those are of course safe to use in different threads).	3108	loops - those are of course safe to use in different threads).
2975		3109
2976	Sometimes, however, you need to wake up another event loop you do not	3110	Sometimes, however, you need to wake up an event loop you do not control,
2977	control, for example because it belongs to another thread. This is what	3111	for example because it belongs to another thread. This is what C<ev_async>
2978	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3112	watchers do: as long as the C<ev_async> watcher is active, you can signal
2979	can signal it by calling C<ev_async_send>, which is thread- and signal	3113	it by calling C<ev_async_send>, which is thread- and signal safe.
2980	safe.
2981		3114
2982	This functionality is very similar to C<ev_signal> watchers, as signals,	3115	This functionality is very similar to C<ev_signal> watchers, as signals,
2983	too, are asynchronous in nature, and signals, too, will be compressed	3116	too, are asynchronous in nature, and signals, too, will be compressed
2984	(i.e. the number of callback invocations may be less than the number of	3117	(i.e. the number of callback invocations may be less than the number of
2985	C<ev_async_sent> calls).	3118	C<ev_async_sent> calls).
…		…
3140		3273
3141	If C<timeout> is less than 0, then no timeout watcher will be	3274	If C<timeout> is less than 0, then no timeout watcher will be
3142	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3275	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
3143	repeat = 0) will be started. C<0> is a valid timeout.	3276	repeat = 0) will be started. C<0> is a valid timeout.
3144		3277
3145	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	3278	The callback has the type C<void (*cb)(int revents, void *arg)> and is
3146	passed an C<revents> set like normal event callbacks (a combination of	3279	passed an C<revents> set like normal event callbacks (a combination of
3147	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3280	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
3148	value passed to C<ev_once>. Note that it is possible to receive I<both>	3281	value passed to C<ev_once>. Note that it is possible to receive I<both>
3149	a timeout and an io event at the same time - you probably should give io	3282	a timeout and an io event at the same time - you probably should give io
3150	events precedence.	3283	events precedence.
3151		3284
3152	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3285	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
3153		3286
3154	static void stdin_ready (int revents, void *arg)	3287	static void stdin_ready (int revents, void *arg)
3155	{	3288	{
3156	if (revents & EV_READ)	3289	if (revents & EV_READ)
3157	/* stdin might have data for us, joy! */;	3290	/* stdin might have data for us, joy! */;
3158	else if (revents & EV_TIMEOUT)	3291	else if (revents & EV_TIMER)
3159	/* doh, nothing entered */;	3292	/* doh, nothing entered */;
3160	}	3293	}
3161		3294
3162	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3295	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3163		3296
…		…
3297	myclass obj;	3430	myclass obj;
3298	ev::io iow;	3431	ev::io iow;
3299	iow.set <myclass, &myclass::io_cb> (&obj);	3432	iow.set <myclass, &myclass::io_cb> (&obj);
3300		3433
3301	=item w->set (object *)	3434	=item w->set (object *)
3302
3303	This is an B<experimental> feature that might go away in a future version.
3304		3435
3305	This is a variation of a method callback - leaving out the method to call	3436	This is a variation of a method callback - leaving out the method to call
3306	will default the method to C<operator ()>, which makes it possible to use	3437	will default the method to C<operator ()>, which makes it possible to use
3307	functor objects without having to manually specify the C<operator ()> all	3438	functor objects without having to manually specify the C<operator ()> all
3308	the time. Incidentally, you can then also leave out the template argument	3439	the time. Incidentally, you can then also leave out the template argument
…		…
3348	Associates a different C<struct ev_loop> with this watcher. You can only	3479	Associates a different C<struct ev_loop> with this watcher. You can only
3349	do this when the watcher is inactive (and not pending either).	3480	do this when the watcher is inactive (and not pending either).
3350		3481
3351	=item w->set ([arguments])	3482	=item w->set ([arguments])
3352		3483
3353	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3484	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3354	called at least once. Unlike the C counterpart, an active watcher gets	3485	method or a suitable start method must be called at least once. Unlike the
3355	automatically stopped and restarted when reconfiguring it with this	3486	C counterpart, an active watcher gets automatically stopped and restarted
3356	method.	3487	when reconfiguring it with this method.
3357		3488
3358	=item w->start ()	3489	=item w->start ()
3359		3490
3360	Starts the watcher. Note that there is no C<loop> argument, as the	3491	Starts the watcher. Note that there is no C<loop> argument, as the
3361	constructor already stores the event loop.	3492	constructor already stores the event loop.
3362		3493
		3494	=item w->start ([arguments])
		3495
		3496	Instead of calling C<set> and C<start> methods separately, it is often
		3497	convenient to wrap them in one call. Uses the same type of arguments as
		3498	the configure C<set> method of the watcher.
		3499
3363	=item w->stop ()	3500	=item w->stop ()
3364		3501
3365	Stops the watcher if it is active. Again, no C<loop> argument.	3502	Stops the watcher if it is active. Again, no C<loop> argument.
3366		3503
3367	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3504	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3379		3516
3380	=back	3517	=back
3381		3518
3382	=back	3519	=back
3383		3520
3384	Example: Define a class with an IO and idle watcher, start one of them in	3521	Example: Define a class with two I/O and idle watchers, start the I/O
3385	the constructor.	3522	watchers in the constructor.
3386		3523
3387	class myclass	3524	class myclass
3388	{	3525	{
3389	ev::io io ; void io_cb (ev::io &w, int revents);	3526	ev::io io ; void io_cb (ev::io &w, int revents);
		3527	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3390	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3528	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3391		3529
3392	myclass (int fd)	3530	myclass (int fd)
3393	{	3531	{
3394	io .set <myclass, &myclass::io_cb > (this);	3532	io .set <myclass, &myclass::io_cb > (this);
		3533	io2 .set <myclass, &myclass::io2_cb > (this);
3395	idle.set <myclass, &myclass::idle_cb> (this);	3534	idle.set <myclass, &myclass::idle_cb> (this);
3396		3535
3397	io.start (fd, ev::READ);	3536	io.set (fd, ev::WRITE); // configure the watcher
		3537	io.start (); // start it whenever convenient
		3538
		3539	io2.start (fd, ev::READ); // set + start in one call
3398	}	3540	}
3399	};	3541	};
3400		3542
3401		3543
3402	=head1 OTHER LANGUAGE BINDINGS	3544	=head1 OTHER LANGUAGE BINDINGS
…		…
3450	Erkki Seppala has written Ocaml bindings for libev, to be found at	3592	Erkki Seppala has written Ocaml bindings for libev, to be found at
3451	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.	3593	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
3452		3594
3453	=item Lua	3595	=item Lua
3454		3596
3455	Brian Maher has written a partial interface to libev	3597	Brian Maher has written a partial interface to libev for lua (at the
3456	for lua (only C<ev_io> and C<ev_timer>), to be found at	3598	time of this writing, only C<ev_io> and C<ev_timer>), to be found at
3457	L<http://github.com/brimworks/lua-ev>.	3599	L<http://github.com/brimworks/lua-ev>.
3458		3600
3459	=back	3601	=back
3460		3602
3461		3603
…		…
3476	loop argument"). The C<EV_A> form is used when this is the sole argument,	3618	loop argument"). The C<EV_A> form is used when this is the sole argument,
3477	C<EV_A_> is used when other arguments are following. Example:	3619	C<EV_A_> is used when other arguments are following. Example:
3478		3620
3479	ev_unref (EV_A);	3621	ev_unref (EV_A);
3480	ev_timer_add (EV_A_ watcher);	3622	ev_timer_add (EV_A_ watcher);
3481	ev_loop (EV_A_ 0);	3623	ev_run (EV_A_ 0);
3482		3624
3483	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3625	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3484	which is often provided by the following macro.	3626	which is often provided by the following macro.
3485		3627
3486	=item C<EV_P>, C<EV_P_>	3628	=item C<EV_P>, C<EV_P_>
…		…
3526	}	3668	}
3527		3669
3528	ev_check check;	3670	ev_check check;
3529	ev_check_init (&check, check_cb);	3671	ev_check_init (&check, check_cb);
3530	ev_check_start (EV_DEFAULT_ &check);	3672	ev_check_start (EV_DEFAULT_ &check);
3531	ev_loop (EV_DEFAULT_ 0);	3673	ev_run (EV_DEFAULT_ 0);
3532		3674
3533	=head1 EMBEDDING	3675	=head1 EMBEDDING
3534		3676
3535	Libev can (and often is) directly embedded into host	3677	Libev can (and often is) directly embedded into host
3536	applications. Examples of applications that embed it include the Deliantra	3678	applications. Examples of applications that embed it include the Deliantra
…		…
3616	libev.m4	3758	libev.m4
3617		3759
3618	=head2 PREPROCESSOR SYMBOLS/MACROS	3760	=head2 PREPROCESSOR SYMBOLS/MACROS
3619		3761
3620	Libev can be configured via a variety of preprocessor symbols you have to	3762	Libev can be configured via a variety of preprocessor symbols you have to
3621	define before including any of its files. The default in the absence of	3763	define before including (or compiling) any of its files. The default in
3622	autoconf is documented for every option.	3764	the absence of autoconf is documented for every option.
		3765
		3766	Symbols marked with "(h)" do not change the ABI, and can have different
		3767	values when compiling libev vs. including F<ev.h>, so it is permissible
		3768	to redefine them before including F<ev.h> without breaking compatibility
		3769	to a compiled library. All other symbols change the ABI, which means all
		3770	users of libev and the libev code itself must be compiled with compatible
		3771	settings.
3623		3772
3624	=over 4	3773	=over 4
3625		3774
		3775	=item EV_COMPAT3 (h)
		3776
		3777	Backwards compatibility is a major concern for libev. This is why this
		3778	release of libev comes with wrappers for the functions and symbols that
		3779	have been renamed between libev version 3 and 4.
		3780
		3781	You can disable these wrappers (to test compatibility with future
		3782	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3783	sources. This has the additional advantage that you can drop the C<struct>
		3784	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3785	typedef in that case.
		3786
		3787	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3788	and in some even more future version the compatibility code will be
		3789	removed completely.
		3790
3626	=item EV_STANDALONE	3791	=item EV_STANDALONE (h)
3627		3792
3628	Must always be C<1> if you do not use autoconf configuration, which	3793	Must always be C<1> if you do not use autoconf configuration, which
3629	keeps libev from including F<config.h>, and it also defines dummy	3794	keeps libev from including F<config.h>, and it also defines dummy
3630	implementations for some libevent functions (such as logging, which is not	3795	implementations for some libevent functions (such as logging, which is not
3631	supported). It will also not define any of the structs usually found in	3796	supported). It will also not define any of the structs usually found in
…		…
3781	as well as for signal and thread safety in C<ev_async> watchers.	3946	as well as for signal and thread safety in C<ev_async> watchers.
3782		3947
3783	In the absence of this define, libev will use C<sig_atomic_t volatile>	3948	In the absence of this define, libev will use C<sig_atomic_t volatile>
3784	(from F<signal.h>), which is usually good enough on most platforms.	3949	(from F<signal.h>), which is usually good enough on most platforms.
3785		3950
3786	=item EV_H	3951	=item EV_H (h)
3787		3952
3788	The name of the F<ev.h> header file used to include it. The default if	3953	The name of the F<ev.h> header file used to include it. The default if
3789	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be	3954	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
3790	used to virtually rename the F<ev.h> header file in case of conflicts.	3955	used to virtually rename the F<ev.h> header file in case of conflicts.
3791		3956
3792	=item EV_CONFIG_H	3957	=item EV_CONFIG_H (h)
3793		3958
3794	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	3959	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
3795	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	3960	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
3796	C<EV_H>, above.	3961	C<EV_H>, above.
3797		3962
3798	=item EV_EVENT_H	3963	=item EV_EVENT_H (h)
3799		3964
3800	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	3965	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
3801	of how the F<event.h> header can be found, the default is C<"event.h">.	3966	of how the F<event.h> header can be found, the default is C<"event.h">.
3802		3967
3803	=item EV_PROTOTYPES	3968	=item EV_PROTOTYPES (h)
3804		3969
3805	If defined to be C<0>, then F<ev.h> will not define any function	3970	If defined to be C<0>, then F<ev.h> will not define any function
3806	prototypes, but still define all the structs and other symbols. This is	3971	prototypes, but still define all the structs and other symbols. This is
3807	occasionally useful if you want to provide your own wrapper functions	3972	occasionally useful if you want to provide your own wrapper functions
3808	around libev functions.	3973	around libev functions.
…		…
3830	fine.	3995	fine.
3831		3996
3832	If your embedding application does not need any priorities, defining these	3997	If your embedding application does not need any priorities, defining these
3833	both to C<0> will save some memory and CPU.	3998	both to C<0> will save some memory and CPU.
3834		3999
3835	=item EV_PERIODIC_ENABLE	4000	=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
		4001	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
		4002	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3836		4003
3837	If undefined or defined to be C<1>, then periodic timers are supported. If	4004	If undefined or defined to be C<1> (and the platform supports it), then
3838	defined to be C<0>, then they are not. Disabling them saves a few kB of	4005	the respective watcher type is supported. If defined to be C<0>, then it
3839	code.	4006	is not. Disabling watcher types mainly saves code size.
3840		4007
3841	=item EV_IDLE_ENABLE	4008	=item EV_FEATURES
3842
3843	If undefined or defined to be C<1>, then idle watchers are supported. If
3844	defined to be C<0>, then they are not. Disabling them saves a few kB of
3845	code.
3846
3847	=item EV_EMBED_ENABLE
3848
3849	If undefined or defined to be C<1>, then embed watchers are supported. If
3850	defined to be C<0>, then they are not. Embed watchers rely on most other
3851	watcher types, which therefore must not be disabled.
3852
3853	=item EV_STAT_ENABLE
3854
3855	If undefined or defined to be C<1>, then stat watchers are supported. If
3856	defined to be C<0>, then they are not.
3857
3858	=item EV_FORK_ENABLE
3859
3860	If undefined or defined to be C<1>, then fork watchers are supported. If
3861	defined to be C<0>, then they are not.
3862
3863	=item EV_ASYNC_ENABLE
3864
3865	If undefined or defined to be C<1>, then async watchers are supported. If
3866	defined to be C<0>, then they are not.
3867
3868	=item EV_MINIMAL
3869		4009
3870	If you need to shave off some kilobytes of code at the expense of some	4010	If you need to shave off some kilobytes of code at the expense of some
3871	speed (but with the full API), define this symbol to C<1>. Currently this	4011	speed (but with the full API), you can define this symbol to request
3872	is used to override some inlining decisions, saves roughly 30% code size	4012	certain subsets of functionality. The default is to enable all features
3873	on amd64. It also selects a much smaller 2-heap for timer management over	4013	that can be enabled on the platform.
3874	the default 4-heap.
3875		4014
3876	You can save even more by disabling watcher types you do not need	4015	A typical way to use this symbol is to define it to C<0> (or to a bitset
3877	and setting C<EV_MAXPRI> == C<EV_MINPRI>. Also, disabling C<assert>	4016	with some broad features you want) and then selectively re-enable
3878	(C<-DNDEBUG>) will usually reduce code size a lot.	4017	additional parts you want, for example if you want everything minimal,
		4018	but multiple event loop support, async and child watchers and the poll
		4019	backend, use this:
3879		4020
3880	Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to	4021	#define EV_FEATURES 0
3881	provide a bare-bones event library. See C<ev.h> for details on what parts	4022	#define EV_MULTIPLICITY 1
3882	of the API are still available, and do not complain if this subset changes	4023	#define EV_USE_POLL 1
3883	over time.	4024	#define EV_CHILD_ENABLE 1
		4025	#define EV_ASYNC_ENABLE 1
		4026
		4027	The actual value is a bitset, it can be a combination of the following
		4028	values:
		4029
		4030	=over 4
		4031
		4032	=item C<1> - faster/larger code
		4033
		4034	Use larger code to speed up some operations.
		4035
		4036	Currently this is used to override some inlining decisions (enlarging the
		4037	code size by roughly 30% on amd64).
		4038
		4039	When optimising for size, use of compiler flags such as C<-Os> with
		4040	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
		4041	assertions.
		4042
		4043	=item C<2> - faster/larger data structures
		4044
		4045	Replaces the small 2-heap for timer management by a faster 4-heap, larger
		4046	hash table sizes and so on. This will usually further increase code size
		4047	and can additionally have an effect on the size of data structures at
		4048	runtime.
		4049
		4050	=item C<4> - full API configuration
		4051
		4052	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
		4053	enables multiplicity (C<EV_MULTIPLICITY>=1).
		4054
		4055	=item C<8> - full API
		4056
		4057	This enables a lot of the "lesser used" API functions. See C<ev.h> for
		4058	details on which parts of the API are still available without this
		4059	feature, and do not complain if this subset changes over time.
		4060
		4061	=item C<16> - enable all optional watcher types
		4062
		4063	Enables all optional watcher types. If you want to selectively enable
		4064	only some watcher types other than I/O and timers (e.g. prepare,
		4065	embed, async, child...) you can enable them manually by defining
		4066	C<EV_watchertype_ENABLE> to C<1> instead.
		4067
		4068	=item C<32> - enable all backends
		4069
		4070	This enables all backends - without this feature, you need to enable at
		4071	least one backend manually (C<EV_USE_SELECT> is a good choice).
		4072
		4073	=item C<64> - enable OS-specific "helper" APIs
		4074
		4075	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
		4076	default.
		4077
		4078	=back
		4079
		4080	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
		4081	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
		4082	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
		4083	watchers, timers and monotonic clock support.
		4084
		4085	With an intelligent-enough linker (gcc+binutils are intelligent enough
		4086	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
		4087	your program might be left out as well - a binary starting a timer and an
		4088	I/O watcher then might come out at only 5Kb.
		4089
		4090	=item EV_AVOID_STDIO
		4091
		4092	If this is set to C<1> at compiletime, then libev will avoid using stdio
		4093	functions (printf, scanf, perror etc.). This will increase the code size
		4094	somewhat, but if your program doesn't otherwise depend on stdio and your
		4095	libc allows it, this avoids linking in the stdio library which is quite
		4096	big.
		4097
		4098	Note that error messages might become less precise when this option is
		4099	enabled.
3884		4100
3885	=item EV_NSIG	4101	=item EV_NSIG
3886		4102
3887	The highest supported signal number, +1 (or, the number of	4103	The highest supported signal number, +1 (or, the number of
3888	signals): Normally, libev tries to deduce the maximum number of signals	4104	signals): Normally, libev tries to deduce the maximum number of signals
3889	automatically, but sometimes this fails, in which case it can be	4105	automatically, but sometimes this fails, in which case it can be
3890	specified. Also, using a lower number than detected (C<32> should be	4106	specified. Also, using a lower number than detected (C<32> should be
3891	good for about any system in existance) can save some memory, as libev	4107	good for about any system in existence) can save some memory, as libev
3892	statically allocates some 12-24 bytes per signal number.	4108	statically allocates some 12-24 bytes per signal number.
3893		4109
3894	=item EV_PID_HASHSIZE	4110	=item EV_PID_HASHSIZE
3895		4111
3896	C<ev_child> watchers use a small hash table to distribute workload by	4112	C<ev_child> watchers use a small hash table to distribute workload by
3897	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	4113	pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
3898	than enough. If you need to manage thousands of children you might want to	4114	usually more than enough. If you need to manage thousands of children you
3899	increase this value (I<must> be a power of two).	4115	might want to increase this value (I<must> be a power of two).
3900		4116
3901	=item EV_INOTIFY_HASHSIZE	4117	=item EV_INOTIFY_HASHSIZE
3902		4118
3903	C<ev_stat> watchers use a small hash table to distribute workload by	4119	C<ev_stat> watchers use a small hash table to distribute workload by
3904	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	4120	inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
3905	usually more than enough. If you need to manage thousands of C<ev_stat>	4121	disabled), usually more than enough. If you need to manage thousands of
3906	watchers you might want to increase this value (I<must> be a power of	4122	C<ev_stat> watchers you might want to increase this value (I<must> be a
3907	two).	4123	power of two).
3908		4124
3909	=item EV_USE_4HEAP	4125	=item EV_USE_4HEAP
3910		4126
3911	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4127	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3912	timer and periodics heaps, libev uses a 4-heap when this symbol is defined	4128	timer and periodics heaps, libev uses a 4-heap when this symbol is defined
3913	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably	4129	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
3914	faster performance with many (thousands) of watchers.	4130	faster performance with many (thousands) of watchers.
3915		4131
3916	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4132	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3917	(disabled).	4133	will be C<0>.
3918		4134
3919	=item EV_HEAP_CACHE_AT	4135	=item EV_HEAP_CACHE_AT
3920		4136
3921	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4137	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3922	timer and periodics heaps, libev can cache the timestamp (I<at>) within	4138	timer and periodics heaps, libev can cache the timestamp (I<at>) within
3923	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	4139	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3924	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	4140	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3925	but avoids random read accesses on heap changes. This improves performance	4141	but avoids random read accesses on heap changes. This improves performance
3926	noticeably with many (hundreds) of watchers.	4142	noticeably with many (hundreds) of watchers.
3927		4143
3928	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4144	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3929	(disabled).	4145	will be C<0>.
3930		4146
3931	=item EV_VERIFY	4147	=item EV_VERIFY
3932		4148
3933	Controls how much internal verification (see C<ev_loop_verify ()>) will	4149	Controls how much internal verification (see C<ev_verify ()>) will
3934	be done: If set to C<0>, no internal verification code will be compiled	4150	be done: If set to C<0>, no internal verification code will be compiled
3935	in. If set to C<1>, then verification code will be compiled in, but not	4151	in. If set to C<1>, then verification code will be compiled in, but not
3936	called. If set to C<2>, then the internal verification code will be	4152	called. If set to C<2>, then the internal verification code will be
3937	called once per loop, which can slow down libev. If set to C<3>, then the	4153	called once per loop, which can slow down libev. If set to C<3>, then the
3938	verification code will be called very frequently, which will slow down	4154	verification code will be called very frequently, which will slow down
3939	libev considerably.	4155	libev considerably.
3940		4156
3941	The default is C<1>, unless C<EV_MINIMAL> is set, in which case it will be	4157	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3942	C<0>.	4158	will be C<0>.
3943		4159
3944	=item EV_COMMON	4160	=item EV_COMMON
3945		4161
3946	By default, all watchers have a C<void *data> member. By redefining	4162	By default, all watchers have a C<void *data> member. By redefining
3947	this macro to a something else you can include more and other types of	4163	this macro to something else you can include more and other types of
3948	members. You have to define it each time you include one of the files,	4164	members. You have to define it each time you include one of the files,
3949	though, and it must be identical each time.	4165	though, and it must be identical each time.
3950		4166
3951	For example, the perl EV module uses something like this:	4167	For example, the perl EV module uses something like this:
3952		4168
…		…
4005	file.	4221	file.
4006		4222
4007	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4223	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
4008	that everybody includes and which overrides some configure choices:	4224	that everybody includes and which overrides some configure choices:
4009		4225
4010	#define EV_MINIMAL 1	4226	#define EV_FEATURES 8
4011	#define EV_USE_POLL 0	4227	#define EV_USE_SELECT 1
4012	#define EV_MULTIPLICITY 0
4013	#define EV_PERIODIC_ENABLE 0	4228	#define EV_PREPARE_ENABLE 1
		4229	#define EV_IDLE_ENABLE 1
4014	#define EV_STAT_ENABLE 0	4230	#define EV_SIGNAL_ENABLE 1
4015	#define EV_FORK_ENABLE 0	4231	#define EV_CHILD_ENABLE 1
		4232	#define EV_USE_STDEXCEPT 0
4016	#define EV_CONFIG_H <config.h>	4233	#define EV_CONFIG_H <config.h>
4017	#define EV_MINPRI 0
4018	#define EV_MAXPRI 0
4019		4234
4020	#include "ev++.h"	4235	#include "ev++.h"
4021		4236
4022	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4237	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
4023		4238
…		…
4154	userdata *u = ev_userdata (EV_A);	4369	userdata *u = ev_userdata (EV_A);
4155	pthread_mutex_lock (&u->lock);	4370	pthread_mutex_lock (&u->lock);
4156	}	4371	}
4157		4372
4158	The event loop thread first acquires the mutex, and then jumps straight	4373	The event loop thread first acquires the mutex, and then jumps straight
4159	into C<ev_loop>:	4374	into C<ev_run>:
4160		4375
4161	void *	4376	void *
4162	l_run (void *thr_arg)	4377	l_run (void *thr_arg)
4163	{	4378	{
4164	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4379	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4165		4380
4166	l_acquire (EV_A);	4381	l_acquire (EV_A);
4167	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4382	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4168	ev_loop (EV_A_ 0);	4383	ev_run (EV_A_ 0);
4169	l_release (EV_A);	4384	l_release (EV_A);
4170		4385
4171	return 0;	4386	return 0;
4172	}	4387	}
4173		4388
…		…
4225		4440
4226	=head3 COROUTINES	4441	=head3 COROUTINES
4227		4442
4228	Libev is very accommodating to coroutines ("cooperative threads"):	4443	Libev is very accommodating to coroutines ("cooperative threads"):
4229	libev fully supports nesting calls to its functions from different	4444	libev fully supports nesting calls to its functions from different
4230	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4445	coroutines (e.g. you can call C<ev_run> on the same loop from two
4231	different coroutines, and switch freely between both coroutines running	4446	different coroutines, and switch freely between both coroutines running
4232	the loop, as long as you don't confuse yourself). The only exception is	4447	the loop, as long as you don't confuse yourself). The only exception is
4233	that you must not do this from C<ev_periodic> reschedule callbacks.	4448	that you must not do this from C<ev_periodic> reschedule callbacks.
4234		4449
4235	Care has been taken to ensure that libev does not keep local state inside	4450	Care has been taken to ensure that libev does not keep local state inside
4236	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4451	C<ev_run>, and other calls do not usually allow for coroutine switches as
4237	they do not call any callbacks.	4452	they do not call any callbacks.
4238		4453
4239	=head2 COMPILER WARNINGS	4454	=head2 COMPILER WARNINGS
4240		4455
4241	Depending on your compiler and compiler settings, you might get no or a	4456	Depending on your compiler and compiler settings, you might get no or a
…		…
4252	maintainable.	4467	maintainable.
4253		4468
4254	And of course, some compiler warnings are just plain stupid, or simply	4469	And of course, some compiler warnings are just plain stupid, or simply
4255	wrong (because they don't actually warn about the condition their message	4470	wrong (because they don't actually warn about the condition their message
4256	seems to warn about). For example, certain older gcc versions had some	4471	seems to warn about). For example, certain older gcc versions had some
4257	warnings that resulted an extreme number of false positives. These have	4472	warnings that resulted in an extreme number of false positives. These have
4258	been fixed, but some people still insist on making code warn-free with	4473	been fixed, but some people still insist on making code warn-free with
4259	such buggy versions.	4474	such buggy versions.
4260		4475
4261	While libev is written to generate as few warnings as possible,	4476	While libev is written to generate as few warnings as possible,
4262	"warn-free" code is not a goal, and it is recommended not to build libev	4477	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4298	I suggest using suppression lists.	4513	I suggest using suppression lists.
4299		4514
4300		4515
4301	=head1 PORTABILITY NOTES	4516	=head1 PORTABILITY NOTES
4302		4517
		4518	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4519
		4520	GNU/Linux is the only common platform that supports 64 bit file/large file
		4521	interfaces but I<disables> them by default.
		4522
		4523	That means that libev compiled in the default environment doesn't support
		4524	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4525
		4526	Unfortunately, many programs try to work around this GNU/Linux issue
		4527	by enabling the large file API, which makes them incompatible with the
		4528	standard libev compiled for their system.
		4529
		4530	Likewise, libev cannot enable the large file API itself as this would
		4531	suddenly make it incompatible to the default compile time environment,
		4532	i.e. all programs not using special compile switches.
		4533
		4534	=head2 OS/X AND DARWIN BUGS
		4535
		4536	The whole thing is a bug if you ask me - basically any system interface
		4537	you touch is broken, whether it is locales, poll, kqueue or even the
		4538	OpenGL drivers.
		4539
		4540	=head3 C<kqueue> is buggy
		4541
		4542	The kqueue syscall is broken in all known versions - most versions support
		4543	only sockets, many support pipes.
		4544
		4545	Libev tries to work around this by not using C<kqueue> by default on this
		4546	rotten platform, but of course you can still ask for it when creating a
		4547	loop - embedding a socket-only kqueue loop into a select-based one is
		4548	probably going to work well.
		4549
		4550	=head3 C<poll> is buggy
		4551
		4552	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4553	implementation by something calling C<kqueue> internally around the 10.5.6
		4554	release, so now C<kqueue> I<and> C<poll> are broken.
		4555
		4556	Libev tries to work around this by not using C<poll> by default on
		4557	this rotten platform, but of course you can still ask for it when creating
		4558	a loop.
		4559
		4560	=head3 C<select> is buggy
		4561
		4562	All that's left is C<select>, and of course Apple found a way to fuck this
		4563	one up as well: On OS/X, C<select> actively limits the number of file
		4564	descriptors you can pass in to 1024 - your program suddenly crashes when
		4565	you use more.
		4566
		4567	There is an undocumented "workaround" for this - defining
		4568	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4569	work on OS/X.
		4570
		4571	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4572
		4573	=head3 C<errno> reentrancy
		4574
		4575	The default compile environment on Solaris is unfortunately so
		4576	thread-unsafe that you can't even use components/libraries compiled
		4577	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4578	defined by default. A valid, if stupid, implementation choice.
		4579
		4580	If you want to use libev in threaded environments you have to make sure
		4581	it's compiled with C<_REENTRANT> defined.
		4582
		4583	=head3 Event port backend
		4584
		4585	The scalable event interface for Solaris is called "event
		4586	ports". Unfortunately, this mechanism is very buggy in all major
		4587	releases. If you run into high CPU usage, your program freezes or you get
		4588	a large number of spurious wakeups, make sure you have all the relevant
		4589	and latest kernel patches applied. No, I don't know which ones, but there
		4590	are multiple ones to apply, and afterwards, event ports actually work
		4591	great.
		4592
		4593	If you can't get it to work, you can try running the program by setting
		4594	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4595	C<select> backends.
		4596
		4597	=head2 AIX POLL BUG
		4598
		4599	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4600	this by trying to avoid the poll backend altogether (i.e. it's not even
		4601	compiled in), which normally isn't a big problem as C<select> works fine
		4602	with large bitsets on AIX, and AIX is dead anyway.
		4603
4303	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4604	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4605
		4606	=head3 General issues
4304		4607
4305	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4608	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4306	requires, and its I/O model is fundamentally incompatible with the POSIX	4609	requires, and its I/O model is fundamentally incompatible with the POSIX
4307	model. Libev still offers limited functionality on this platform in	4610	model. Libev still offers limited functionality on this platform in
4308	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4611	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4309	descriptors. This only applies when using Win32 natively, not when using	4612	descriptors. This only applies when using Win32 natively, not when using
4310	e.g. cygwin.	4613	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4614	as every compielr comes with a slightly differently broken/incompatible
		4615	environment.
4311		4616
4312	Lifting these limitations would basically require the full	4617	Lifting these limitations would basically require the full
4313	re-implementation of the I/O system. If you are into these kinds of	4618	re-implementation of the I/O system. If you are into this kind of thing,
4314	things, then note that glib does exactly that for you in a very portable	4619	then note that glib does exactly that for you in a very portable way (note
4315	way (note also that glib is the slowest event library known to man).	4620	also that glib is the slowest event library known to man).
4316		4621
4317	There is no supported compilation method available on windows except	4622	There is no supported compilation method available on windows except
4318	embedding it into other applications.	4623	embedding it into other applications.
4319		4624
4320	Sensible signal handling is officially unsupported by Microsoft - libev	4625	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4348	you do I<not> compile the F<ev.c> or any other embedded source files!):	4653	you do I<not> compile the F<ev.c> or any other embedded source files!):
4349		4654
4350	#include "evwrap.h"	4655	#include "evwrap.h"
4351	#include "ev.c"	4656	#include "ev.c"
4352		4657
4353	=over 4
4354
4355	=item The winsocket select function	4658	=head3 The winsocket C<select> function
4356		4659
4357	The winsocket C<select> function doesn't follow POSIX in that it	4660	The winsocket C<select> function doesn't follow POSIX in that it
4358	requires socket I<handles> and not socket I<file descriptors> (it is	4661	requires socket I<handles> and not socket I<file descriptors> (it is
4359	also extremely buggy). This makes select very inefficient, and also	4662	also extremely buggy). This makes select very inefficient, and also
4360	requires a mapping from file descriptors to socket handles (the Microsoft	4663	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4369	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4672	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4370		4673
4371	Note that winsockets handling of fd sets is O(n), so you can easily get a	4674	Note that winsockets handling of fd sets is O(n), so you can easily get a
4372	complexity in the O(n²) range when using win32.	4675	complexity in the O(n²) range when using win32.
4373		4676
4374	=item Limited number of file descriptors	4677	=head3 Limited number of file descriptors
4375		4678
4376	Windows has numerous arbitrary (and low) limits on things.	4679	Windows has numerous arbitrary (and low) limits on things.
4377		4680
4378	Early versions of winsocket's select only supported waiting for a maximum	4681	Early versions of winsocket's select only supported waiting for a maximum
4379	of C<64> handles (probably owning to the fact that all windows kernels	4682	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4394	runtime libraries. This might get you to about C<512> or C<2048> sockets	4697	runtime libraries. This might get you to about C<512> or C<2048> sockets
4395	(depending on windows version and/or the phase of the moon). To get more,	4698	(depending on windows version and/or the phase of the moon). To get more,
4396	you need to wrap all I/O functions and provide your own fd management, but	4699	you need to wrap all I/O functions and provide your own fd management, but
4397	the cost of calling select (O(n²)) will likely make this unworkable.	4700	the cost of calling select (O(n²)) will likely make this unworkable.
4398		4701
4399	=back
4400
4401	=head2 PORTABILITY REQUIREMENTS	4702	=head2 PORTABILITY REQUIREMENTS
4402		4703
4403	In addition to a working ISO-C implementation and of course the	4704	In addition to a working ISO-C implementation and of course the
4404	backend-specific APIs, libev relies on a few additional extensions:	4705	backend-specific APIs, libev relies on a few additional extensions:
4405		4706
…		…
4443	watchers.	4744	watchers.
4444		4745
4445	=item C<double> must hold a time value in seconds with enough accuracy	4746	=item C<double> must hold a time value in seconds with enough accuracy
4446		4747
4447	The type C<double> is used to represent timestamps. It is required to	4748	The type C<double> is used to represent timestamps. It is required to
4448	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4749	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4449	enough for at least into the year 4000. This requirement is fulfilled by	4750	good enough for at least into the year 4000 with millisecond accuracy
		4751	(the design goal for libev). This requirement is overfulfilled by
4450	implementations implementing IEEE 754, which is basically all existing	4752	implementations using IEEE 754, which is basically all existing ones. With
4451	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4753	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4452	2200.
4453		4754
4454	=back	4755	=back
4455		4756
4456	If you know of other additional requirements drop me a note.	4757	If you know of other additional requirements drop me a note.
4457		4758
…		…
4525	involves iterating over all running async watchers or all signal numbers.	4826	involves iterating over all running async watchers or all signal numbers.
4526		4827
4527	=back	4828	=back
4528		4829
4529		4830
		4831	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4832
		4833	The major version 4 introduced some minor incompatible changes to the API.
		4834
		4835	At the moment, the C<ev.h> header file tries to implement superficial
		4836	compatibility, so most programs should still compile. Those might be
		4837	removed in later versions of libev, so better update early than late.
		4838
		4839	=over 4
		4840
		4841	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4842
		4843	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4844
		4845	ev_loop_destroy (EV_DEFAULT);
		4846	ev_loop_fork (EV_DEFAULT);
		4847
		4848	=item function/symbol renames
		4849
		4850	A number of functions and symbols have been renamed:
		4851
		4852	ev_loop => ev_run
		4853	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4854	EVLOOP_ONESHOT => EVRUN_ONCE
		4855
		4856	ev_unloop => ev_break
		4857	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4858	EVUNLOOP_ONE => EVBREAK_ONE
		4859	EVUNLOOP_ALL => EVBREAK_ALL
		4860
		4861	EV_TIMEOUT => EV_TIMER
		4862
		4863	ev_loop_count => ev_iteration
		4864	ev_loop_depth => ev_depth
		4865	ev_loop_verify => ev_verify
		4866
		4867	Most functions working on C<struct ev_loop> objects don't have an
		4868	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4869	associated constants have been renamed to not collide with the C<struct
		4870	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4871	as all other watcher types. Note that C<ev_loop_fork> is still called
		4872	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4873	typedef.
		4874
		4875	=item C<EV_COMPAT3> backwards compatibility mechanism
		4876
		4877	The backward compatibility mechanism can be controlled by
		4878	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4879	section.
		4880
		4881	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4882
		4883	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4884	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4885	and work, but the library code will of course be larger.
		4886
		4887	=back
		4888
		4889
4530	=head1 GLOSSARY	4890	=head1 GLOSSARY
4531		4891
4532	=over 4	4892	=over 4
4533		4893
4534	=item active	4894	=item active
4535		4895
4536	A watcher is active as long as it has been started (has been attached to	4896	A watcher is active as long as it has been started and not yet stopped.
4537	an event loop) but not yet stopped (disassociated from the event loop).	4897	See L<WATCHER STATES> for details.
4538		4898
4539	=item application	4899	=item application
4540		4900
4541	In this document, an application is whatever is using libev.	4901	In this document, an application is whatever is using libev.
		4902
		4903	=item backend
		4904
		4905	The part of the code dealing with the operating system interfaces.
4542		4906
4543	=item callback	4907	=item callback
4544		4908
4545	The address of a function that is called when some event has been	4909	The address of a function that is called when some event has been
4546	detected. Callbacks are being passed the event loop, the watcher that	4910	detected. Callbacks are being passed the event loop, the watcher that
4547	received the event, and the actual event bitset.	4911	received the event, and the actual event bitset.
4548		4912
4549	=item callback invocation	4913	=item callback/watcher invocation
4550		4914
4551	The act of calling the callback associated with a watcher.	4915	The act of calling the callback associated with a watcher.
4552		4916
4553	=item event	4917	=item event
4554		4918
4555	A change of state of some external event, such as data now being available	4919	A change of state of some external event, such as data now being available
4556	for reading on a file descriptor, time having passed or simply not having	4920	for reading on a file descriptor, time having passed or simply not having
4557	any other events happening anymore.	4921	any other events happening anymore.
4558		4922
4559	In libev, events are represented as single bits (such as C<EV_READ> or	4923	In libev, events are represented as single bits (such as C<EV_READ> or
4560	C<EV_TIMEOUT>).	4924	C<EV_TIMER>).
4561		4925
4562	=item event library	4926	=item event library
4563		4927
4564	A software package implementing an event model and loop.	4928	A software package implementing an event model and loop.
4565		4929
…		…
4573	The model used to describe how an event loop handles and processes	4937	The model used to describe how an event loop handles and processes
4574	watchers and events.	4938	watchers and events.
4575		4939
4576	=item pending	4940	=item pending
4577		4941
4578	A watcher is pending as soon as the corresponding event has been detected,	4942	A watcher is pending as soon as the corresponding event has been
4579	and stops being pending as soon as the watcher will be invoked or its	4943	detected. See L<WATCHER STATES> for details.
4580	pending status is explicitly cleared by the application.
4581
4582	A watcher can be pending, but not active. Stopping a watcher also clears
4583	its pending status.
4584		4944
4585	=item real time	4945	=item real time
4586		4946
4587	The physical time that is observed. It is apparently strictly monotonic :)	4947	The physical time that is observed. It is apparently strictly monotonic :)
4588		4948
…		…
4595	=item watcher	4955	=item watcher
4596		4956
4597	A data structure that describes interest in certain events. Watchers need	4957	A data structure that describes interest in certain events. Watchers need
4598	to be started (attached to an event loop) before they can receive events.	4958	to be started (attached to an event loop) before they can receive events.
4599		4959
4600	=item watcher invocation
4601
4602	The act of calling the callback associated with a watcher.
4603
4604	=back	4960	=back
4605		4961
4606	=head1 AUTHOR	4962	=head1 AUTHOR
4607		4963
4608	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4964	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines