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…		…
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
…		…
118	Libev is very configurable. In this manual the default (and most common)	118	Libev is very configurable. In this manual the default (and most common)
119	configuration will be described, which supports multiple event loops. For	119	configuration will be described, which supports multiple event loops. For
120	more info about various configuration options please have a look at	120	more info about various configuration options please have a look at
121	B<EMBED> section in this manual. If libev was configured without support	121	B<EMBED> section in this manual. If libev was configured without support
122	for multiple event loops, then all functions taking an initial argument of	122	for multiple event loops, then all functions taking an initial argument of
123	name C<loop> (which is always of type C<ev_loop *>) will not have	123	name C<loop> (which is always of type C<struct ev_loop *>) will not have
124	this argument.	124	this argument.
125		125
126	=head2 TIME REPRESENTATION	126	=head2 TIME REPRESENTATION
127		127
128	Libev represents time as a single floating point number, representing	128	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (somewhere	129	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	near the beginning of 1970, details are complicated, don't ask). This	130	somewhere near the beginning of 1970, details are complicated, don't
131	type is called C<ev_tstamp>, which is what you should use too. It usually	131	ask). This type is called C<ev_tstamp>, which is what you should use
132	aliases to the C<double> type in C. When you need to do any calculations	132	too. It usually aliases to the C<double> type in C. When you need to do
133	on it, you should treat it as some floating point value. Unlike the name	133	any calculations on it, you should treat it as some floating point value.
		134
134	component C<stamp> might indicate, it is also used for time differences	135	Unlike the name component C<stamp> might indicate, it is also used for
135	throughout libev.	136	time differences (e.g. delays) throughout libev.
136		137
137	=head1 ERROR HANDLING	138	=head1 ERROR HANDLING
138		139
139	Libev knows three classes of errors: operating system errors, usage errors	140	Libev knows three classes of errors: operating system errors, usage errors
140	and internal errors (bugs).	141	and internal errors (bugs).
…		…
164		165
165	=item ev_tstamp ev_time ()	166	=item ev_tstamp ev_time ()
166		167
167	Returns the current time as libev would use it. Please note that the	168	Returns the current time as libev would use it. Please note that the
168	C<ev_now> function is usually faster and also often returns the timestamp	169	C<ev_now> function is usually faster and also often returns the timestamp
169	you actually want to know.	170	you actually want to know. Also interesting is the combination of
		171	C<ev_update_now> and C<ev_now>.
170		172
171	=item ev_sleep (ev_tstamp interval)	173	=item ev_sleep (ev_tstamp interval)
172		174
173	Sleep for the given interval: The current thread will be blocked until	175	Sleep for the given interval: The current thread will be blocked until
174	either it is interrupted or the given time interval has passed. Basically	176	either it is interrupted or the given time interval has passed. Basically
…		…
191	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
192	compatible to older versions, so a larger minor version alone is usually	194	compatible to older versions, so a larger minor version alone is usually
193	not a problem.	195	not a problem.
194		196
195	Example: Make sure we haven't accidentally been linked against the wrong	197	Example: Make sure we haven't accidentally been linked against the wrong
196	version.	198	version (note, however, that this will not detect other ABI mismatches,
		199	such as LFS or reentrancy).
197		200
198	assert (("libev version mismatch",	201	assert (("libev version mismatch",
199	ev_version_major () == EV_VERSION_MAJOR	202	ev_version_major () == EV_VERSION_MAJOR
200	&& ev_version_minor () >= EV_VERSION_MINOR));	203	&& ev_version_minor () >= EV_VERSION_MINOR));
201		204
…		…
212	assert (("sorry, no epoll, no sex",	215	assert (("sorry, no epoll, no sex",
213	ev_supported_backends () & EVBACKEND_EPOLL));	216	ev_supported_backends () & EVBACKEND_EPOLL));
214		217
215	=item unsigned int ev_recommended_backends ()	218	=item unsigned int ev_recommended_backends ()
216		219
217	Return the set of all backends compiled into this binary of libev and also	220	Return the set of all backends compiled into this binary of libev and
218	recommended for this platform. This set is often smaller than the one	221	also recommended for this platform, meaning it will work for most file
		222	descriptor types. This set is often smaller than the one returned by
219	returned by C<ev_supported_backends>, as for example kqueue is broken on	223	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
220	most BSDs and will not be auto-detected unless you explicitly request it	224	and will not be auto-detected unless you explicitly request it (assuming
221	(assuming you know what you are doing). This is the set of backends that	225	you know what you are doing). This is the set of backends that libev will
222	libev will probe for if you specify no backends explicitly.	226	probe for if you specify no backends explicitly.
223		227
224	=item unsigned int ev_embeddable_backends ()	228	=item unsigned int ev_embeddable_backends ()
225		229
226	Returns the set of backends that are embeddable in other event loops. This	230	Returns the set of backends that are embeddable in other event loops. This
227	is the theoretical, all-platform, value. To find which backends	231	value is platform-specific but can include backends not available on the
228	might be supported on the current system, you would need to look at	232	current system. To find which embeddable backends might be supported on
229	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	233	the current system, you would need to look at C<ev_embeddable_backends ()
230	recommended ones.	234	& ev_supported_backends ()>, likewise for recommended ones.
231		235
232	See the description of C<ev_embed> watchers for more info.	236	See the description of C<ev_embed> watchers for more info.
233		237
234	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]	238	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]
235		239
…		…
289	...	293	...
290	ev_set_syserr_cb (fatal_error);	294	ev_set_syserr_cb (fatal_error);
291		295
292	=back	296	=back
293		297
294	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	298	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
295		299
296	An event loop is described by a C<struct ev_loop *> (the C<struct>	300	An event loop is described by a C<struct ev_loop *> (the C<struct> is
297	is I<not> optional in this case, as there is also an C<ev_loop>	301	I<not> optional in this case unless libev 3 compatibility is disabled, as
298	I<function>).	302	libev 3 had an C<ev_loop> function colliding with the struct name).
299		303
300	The library knows two types of such loops, the I<default> loop, which	304	The library knows two types of such loops, the I<default> loop, which
301	supports signals and child events, and dynamically created loops which do	305	supports signals and child events, and dynamically created event loops
302	not.	306	which do not.
303		307
304	=over 4	308	=over 4
305		309
306	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
307		311
308	This will initialise the default event loop if it hasn't been initialised	312	This returns the "default" event loop object, which is what you should
309	yet and return it. If the default loop could not be initialised, returns	313	normally use when you just need "the event loop". Event loop objects and
310	false. If it already was initialised it simply returns it (and ignores the	314	the C<flags> parameter are described in more detail in the entry for
311	flags. If that is troubling you, check C<ev_backend ()> afterwards).	315	C<ev_loop_new>.
		316
		317	If the default loop is already initialised then this function simply
		318	returns it (and ignores the flags. If that is troubling you, check
		319	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		320	flags, which should almost always be C<0>, unless the caller is also the
		321	one calling C<ev_run> or otherwise qualifies as "the main program".
312		322
313	If you don't know what event loop to use, use the one returned from this	323	If you don't know what event loop to use, use the one returned from this
314	function.	324	function (or via the C<EV_DEFAULT> macro).
315		325
316	Note that this function is I<not> thread-safe, so if you want to use it	326	Note that this function is I<not> thread-safe, so if you want to use it
317	from multiple threads, you have to lock (note also that this is unlikely,	327	from multiple threads, you have to employ some kind of mutex (note also
318	as loops cannot be shared easily between threads anyway).	328	that this case is unlikely, as loops cannot be shared easily between
		329	threads anyway).
319		330
320	The default loop is the only loop that can handle C<ev_signal> and	331	The default loop is the only loop that can handle C<ev_child> watchers,
321	C<ev_child> watchers, and to do this, it always registers a handler	332	and to do this, it always registers a handler for C<SIGCHLD>. If this is
322	for C<SIGCHLD>. If this is a problem for your application you can either	333	a problem for your application you can either create a dynamic loop with
323	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	334	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
324	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	335	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
325	C<ev_default_init>.	336
		337	Example: This is the most typical usage.
		338
		339	if (!ev_default_loop (0))
		340	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		341
		342	Example: Restrict libev to the select and poll backends, and do not allow
		343	environment settings to be taken into account:
		344
		345	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
		346
		347	Example: Use whatever libev has to offer, but make sure that kqueue is
		348	used if available (warning, breaks stuff, best use only with your own
		349	private event loop and only if you know the OS supports your types of
		350	fds):
		351
		352	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
		353
		354	=item struct ev_loop *ev_loop_new (unsigned int flags)
		355
		356	This will create and initialise a new event loop object. If the loop
		357	could not be initialised, returns false.
		358
		359	Note that this function I<is> thread-safe, and one common way to use
		360	libev with threads is indeed to create one loop per thread, and using the
		361	default loop in the "main" or "initial" thread.
326		362
327	The flags argument can be used to specify special behaviour or specific	363	The flags argument can be used to specify special behaviour or specific
328	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	364	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
329		365
330	The following flags are supported:	366	The following flags are supported:
…		…
345	useful to try out specific backends to test their performance, or to work	381	useful to try out specific backends to test their performance, or to work
346	around bugs.	382	around bugs.
347		383
348	=item C<EVFLAG_FORKCHECK>	384	=item C<EVFLAG_FORKCHECK>
349		385
350	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	386	Instead of calling C<ev_loop_fork> manually after a fork, you can also
351	a fork, you can also make libev check for a fork in each iteration by	387	make libev check for a fork in each iteration by enabling this flag.
352	enabling this flag.
353		388
354	This works by calling C<getpid ()> on every iteration of the loop,	389	This works by calling C<getpid ()> on every iteration of the loop,
355	and thus this might slow down your event loop if you do a lot of loop	390	and thus this might slow down your event loop if you do a lot of loop
356	iterations and little real work, but is usually not noticeable (on my	391	iterations and little real work, but is usually not noticeable (on my
357	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	392	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
…		…
370	When this flag is specified, then libev will not attempt to use the	405	When this flag is specified, then libev will not attempt to use the
371	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and	406	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and
372	testing, this flag can be useful to conserve inotify file descriptors, as	407	testing, this flag can be useful to conserve inotify file descriptors, as
373	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.	408	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
374		409
375	=item C<EVFLAG_NOSIGNALFD>	410	=item C<EVFLAG_SIGNALFD>
376		411
377	When this flag is specified, then libev will not attempt to use the	412	When this flag is specified, then libev will attempt to use the
378	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This is	413	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API
379	probably only useful to work around any bugs in libev. Consequently, this	414	delivers signals synchronously, which makes it both faster and might make
380	flag might go away once the signalfd functionality is considered stable,	415	it possible to get the queued signal data. It can also simplify signal
381	so it's useful mostly in environment variables and not in program code.	416	handling with threads, as long as you properly block signals in your
		417	threads that are not interested in handling them.
		418
		419	Signalfd will not be used by default as this changes your signal mask, and
		420	there are a lot of shoddy libraries and programs (glib's threadpool for
		421	example) that can't properly initialise their signal masks.
382		422
383	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	423	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
384		424
385	This is your standard select(2) backend. Not I<completely> standard, as	425	This is your standard select(2) backend. Not I<completely> standard, as
386	libev tries to roll its own fd_set with no limits on the number of fds,	426	libev tries to roll its own fd_set with no limits on the number of fds,
…		…
410		450
411	This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and	451	This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and
412	C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>.	452	C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>.
413		453
414	=item C<EVBACKEND_EPOLL> (value 4, Linux)	454	=item C<EVBACKEND_EPOLL> (value 4, Linux)
		455
		456	Use the linux-specific epoll(7) interface (for both pre- and post-2.6.9
		457	kernels).
415		458
416	For few fds, this backend is a bit little slower than poll and select,	459	For few fds, this backend is a bit little slower than poll and select,
417	but it scales phenomenally better. While poll and select usually scale	460	but it scales phenomenally better. While poll and select usually scale
418	like O(total_fds) where n is the total number of fds (or the highest fd),	461	like O(total_fds) where n is the total number of fds (or the highest fd),
419	epoll scales either O(1) or O(active_fds).	462	epoll scales either O(1) or O(active_fds).
…		…
431	of course I<doesn't>, and epoll just loves to report events for totally	474	of course I<doesn't>, and epoll just loves to report events for totally
432	I<different> file descriptors (even already closed ones, so one cannot	475	I<different> file descriptors (even already closed ones, so one cannot
433	even remove them from the set) than registered in the set (especially	476	even remove them from the set) than registered in the set (especially
434	on SMP systems). Libev tries to counter these spurious notifications by	477	on SMP systems). Libev tries to counter these spurious notifications by
435	employing an additional generation counter and comparing that against the	478	employing an additional generation counter and comparing that against the
436	events to filter out spurious ones, recreating the set when required.	479	events to filter out spurious ones, recreating the set when required. Last
		480	not least, it also refuses to work with some file descriptors which work
		481	perfectly fine with C<select> (files, many character devices...).
437		482
438	While stopping, setting and starting an I/O watcher in the same iteration	483	While stopping, setting and starting an I/O watcher in the same iteration
439	will result in some caching, there is still a system call per such	484	will result in some caching, there is still a system call per such
440	incident (because the same I<file descriptor> could point to a different	485	incident (because the same I<file descriptor> could point to a different
441	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	486	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
539	If one or more of the backend flags are or'ed into the flags value,	584	If one or more of the backend flags are or'ed into the flags value,
540	then only these backends will be tried (in the reverse order as listed	585	then only these backends will be tried (in the reverse order as listed
541	here). If none are specified, all backends in C<ev_recommended_backends	586	here). If none are specified, all backends in C<ev_recommended_backends
542	()> will be tried.	587	()> will be tried.
543		588
544	Example: This is the most typical usage.
545
546	if (!ev_default_loop (0))
547	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
548
549	Example: Restrict libev to the select and poll backends, and do not allow
550	environment settings to be taken into account:
551
552	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
553
554	Example: Use whatever libev has to offer, but make sure that kqueue is
555	used if available (warning, breaks stuff, best use only with your own
556	private event loop and only if you know the OS supports your types of
557	fds):
558
559	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
560
561	=item struct ev_loop *ev_loop_new (unsigned int flags)
562
563	Similar to C<ev_default_loop>, but always creates a new event loop that is
564	always distinct from the default loop. Unlike the default loop, it cannot
565	handle signal and child watchers, and attempts to do so will be greeted by
566	undefined behaviour (or a failed assertion if assertions are enabled).
567
568	Note that this function I<is> thread-safe, and the recommended way to use
569	libev with threads is indeed to create one loop per thread, and using the
570	default loop in the "main" or "initial" thread.
571
572	Example: Try to create a event loop that uses epoll and nothing else.	589	Example: Try to create a event loop that uses epoll and nothing else.
573		590
574	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	591	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
575	if (!epoller)	592	if (!epoller)
576	fatal ("no epoll found here, maybe it hides under your chair");	593	fatal ("no epoll found here, maybe it hides under your chair");
577		594
578	=item ev_default_destroy ()	595	=item ev_loop_destroy (loop)
579		596
580	Destroys the default loop again (frees all memory and kernel state	597	Destroys an event loop object (frees all memory and kernel state
581	etc.). None of the active event watchers will be stopped in the normal	598	etc.). None of the active event watchers will be stopped in the normal
582	sense, so e.g. C<ev_is_active> might still return true. It is your	599	sense, so e.g. C<ev_is_active> might still return true. It is your
583	responsibility to either stop all watchers cleanly yourself I<before>	600	responsibility to either stop all watchers cleanly yourself I<before>
584	calling this function, or cope with the fact afterwards (which is usually	601	calling this function, or cope with the fact afterwards (which is usually
585	the easiest thing, you can just ignore the watchers and/or C<free ()> them	602	the easiest thing, you can just ignore the watchers and/or C<free ()> them
…		…
587		604
588	Note that certain global state, such as signal state (and installed signal	605	Note that certain global state, such as signal state (and installed signal
589	handlers), will not be freed by this function, and related watchers (such	606	handlers), will not be freed by this function, and related watchers (such
590	as signal and child watchers) would need to be stopped manually.	607	as signal and child watchers) would need to be stopped manually.
591		608
592	In general it is not advisable to call this function except in the	609	This function is normally used on loop objects allocated by
593	rare occasion where you really need to free e.g. the signal handling	610	C<ev_loop_new>, but it can also be used on the default loop returned by
		611	C<ev_default_loop>, in which case it is not thread-safe.
		612
		613	Note that it is not advisable to call this function on the default loop
		614	except in the rare occasion where you really need to free it's resources.
594	pipe fds. If you need dynamically allocated loops it is better to use	615	If you need dynamically allocated loops it is better to use C<ev_loop_new>
595	C<ev_loop_new> and C<ev_loop_destroy>).	616	and C<ev_loop_destroy>.
596		617
597	=item ev_loop_destroy (loop)	618	=item ev_loop_fork (loop)
598		619
599	Like C<ev_default_destroy>, but destroys an event loop created by an
600	earlier call to C<ev_loop_new>.
601
602	=item ev_default_fork ()
603
604	This function sets a flag that causes subsequent C<ev_loop> iterations	620	This function sets a flag that causes subsequent C<ev_run> iterations to
605	to reinitialise the kernel state for backends that have one. Despite the	621	reinitialise the kernel state for backends that have one. Despite the
606	name, you can call it anytime, but it makes most sense after forking, in	622	name, you can call it anytime, but it makes most sense after forking, in
607	the child process (or both child and parent, but that again makes little	623	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
608	sense). You I<must> call it in the child before using any of the libev	624	child before resuming or calling C<ev_run>.
609	functions, and it will only take effect at the next C<ev_loop> iteration.	625
		626	Again, you I<have> to call it on I<any> loop that you want to re-use after
		627	a fork, I<even if you do not plan to use the loop in the parent>. This is
		628	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
		629	during fork.
610		630
611	On the other hand, you only need to call this function in the child	631	On the other hand, you only need to call this function in the child
612	process if and only if you want to use the event library in the child. If	632	process if and only if you want to use the event loop in the child. If
613	you just fork+exec, you don't have to call it at all.	633	you just fork+exec or create a new loop in the child, you don't have to
		634	call it at all (in fact, C<epoll> is so badly broken that it makes a
		635	difference, but libev will usually detect this case on its own and do a
		636	costly reset of the backend).
614		637
615	The function itself is quite fast and it's usually not a problem to call	638	The function itself is quite fast and it's usually not a problem to call
616	it just in case after a fork. To make this easy, the function will fit in	639	it just in case after a fork.
617	quite nicely into a call to C<pthread_atfork>:
618		640
		641	Example: Automate calling C<ev_loop_fork> on the default loop when
		642	using pthreads.
		643
		644	static void
		645	post_fork_child (void)
		646	{
		647	ev_loop_fork (EV_DEFAULT);
		648	}
		649
		650	...
619	pthread_atfork (0, 0, ev_default_fork);	651	pthread_atfork (0, 0, post_fork_child);
620
621	=item ev_loop_fork (loop)
622
623	Like C<ev_default_fork>, but acts on an event loop created by
624	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
625	after fork that you want to re-use in the child, and how you do this is
626	entirely your own problem.
627		652
628	=item int ev_is_default_loop (loop)	653	=item int ev_is_default_loop (loop)
629		654
630	Returns true when the given loop is, in fact, the default loop, and false	655	Returns true when the given loop is, in fact, the default loop, and false
631	otherwise.	656	otherwise.
632		657
633	=item unsigned int ev_loop_count (loop)	658	=item unsigned int ev_iteration (loop)
634		659
635	Returns the count of loop iterations for the loop, which is identical to	660	Returns the current iteration count for the event loop, which is identical
636	the number of times libev did poll for new events. It starts at C<0> and	661	to the number of times libev did poll for new events. It starts at C<0>
637	happily wraps around with enough iterations.	662	and happily wraps around with enough iterations.
638		663
639	This value can sometimes be useful as a generation counter of sorts (it	664	This value can sometimes be useful as a generation counter of sorts (it
640	"ticks" the number of loop iterations), as it roughly corresponds with	665	"ticks" the number of loop iterations), as it roughly corresponds with
641	C<ev_prepare> and C<ev_check> calls.	666	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		667	prepare and check phases.
642		668
643	=item unsigned int ev_loop_depth (loop)	669	=item unsigned int ev_depth (loop)
644		670
645	Returns the number of times C<ev_loop> was entered minus the number of	671	Returns the number of times C<ev_run> was entered minus the number of
646	times C<ev_loop> was exited, in other words, the recursion depth.	672	times C<ev_run> was exited, in other words, the recursion depth.
647		673
648	Outside C<ev_loop>, this number is zero. In a callback, this number is	674	Outside C<ev_run>, this number is zero. In a callback, this number is
649	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	675	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
650	in which case it is higher.	676	in which case it is higher.
651		677
652	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	678	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
653	etc.), doesn't count as exit.	679	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		680	ungentleman-like behaviour unless it's really convenient.
654		681
655	=item unsigned int ev_backend (loop)	682	=item unsigned int ev_backend (loop)
656		683
657	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	684	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
658	use.	685	use.
…		…
667		694
668	=item ev_now_update (loop)	695	=item ev_now_update (loop)
669		696
670	Establishes the current time by querying the kernel, updating the time	697	Establishes the current time by querying the kernel, updating the time
671	returned by C<ev_now ()> in the progress. This is a costly operation and	698	returned by C<ev_now ()> in the progress. This is a costly operation and
672	is usually done automatically within C<ev_loop ()>.	699	is usually done automatically within C<ev_run ()>.
673		700
674	This function is rarely useful, but when some event callback runs for a	701	This function is rarely useful, but when some event callback runs for a
675	very long time without entering the event loop, updating libev's idea of	702	very long time without entering the event loop, updating libev's idea of
676	the current time is a good idea.	703	the current time is a good idea.
677		704
…		…
679		706
680	=item ev_suspend (loop)	707	=item ev_suspend (loop)
681		708
682	=item ev_resume (loop)	709	=item ev_resume (loop)
683		710
684	These two functions suspend and resume a loop, for use when the loop is	711	These two functions suspend and resume an event loop, for use when the
685	not used for a while and timeouts should not be processed.	712	loop is not used for a while and timeouts should not be processed.
686		713
687	A typical use case would be an interactive program such as a game: When	714	A typical use case would be an interactive program such as a game: When
688	the user presses C<^Z> to suspend the game and resumes it an hour later it	715	the user presses C<^Z> to suspend the game and resumes it an hour later it
689	would be best to handle timeouts as if no time had actually passed while	716	would be best to handle timeouts as if no time had actually passed while
690	the program was suspended. This can be achieved by calling C<ev_suspend>	717	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
692	C<ev_resume> directly afterwards to resume timer processing.	719	C<ev_resume> directly afterwards to resume timer processing.
693		720
694	Effectively, all C<ev_timer> watchers will be delayed by the time spend	721	Effectively, all C<ev_timer> watchers will be delayed by the time spend
695	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	722	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
696	will be rescheduled (that is, they will lose any events that would have	723	will be rescheduled (that is, they will lose any events that would have
697	occured while suspended).	724	occurred while suspended).
698		725
699	After calling C<ev_suspend> you B<must not> call I<any> function on the	726	After calling C<ev_suspend> you B<must not> call I<any> function on the
700	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	727	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
701	without a previous call to C<ev_suspend>.	728	without a previous call to C<ev_suspend>.
702		729
703	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	730	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
704	event loop time (see C<ev_now_update>).	731	event loop time (see C<ev_now_update>).
705		732
706	=item ev_loop (loop, int flags)	733	=item ev_run (loop, int flags)
707		734
708	Finally, this is it, the event handler. This function usually is called	735	Finally, this is it, the event handler. This function usually is called
709	after you initialised all your watchers and you want to start handling	736	after you have initialised all your watchers and you want to start
710	events.	737	handling events. It will ask the operating system for any new events, call
		738	the watcher callbacks, an then repeat the whole process indefinitely: This
		739	is why event loops are called I<loops>.
711		740
712	If the flags argument is specified as C<0>, it will not return until	741	If the flags argument is specified as C<0>, it will keep handling events
713	either no event watchers are active anymore or C<ev_unloop> was called.	742	until either no event watchers are active anymore or C<ev_break> was
		743	called.
714		744
715	Please note that an explicit C<ev_unloop> is usually better than	745	Please note that an explicit C<ev_break> is usually better than
716	relying on all watchers to be stopped when deciding when a program has	746	relying on all watchers to be stopped when deciding when a program has
717	finished (especially in interactive programs), but having a program	747	finished (especially in interactive programs), but having a program
718	that automatically loops as long as it has to and no longer by virtue	748	that automatically loops as long as it has to and no longer by virtue
719	of relying on its watchers stopping correctly, that is truly a thing of	749	of relying on its watchers stopping correctly, that is truly a thing of
720	beauty.	750	beauty.
721		751
722	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	752	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
723	those events and any already outstanding ones, but will not block your	753	those events and any already outstanding ones, but will not wait and
724	process in case there are no events and will return after one iteration of	754	block your process in case there are no events and will return after one
725	the loop.	755	iteration of the loop. This is sometimes useful to poll and handle new
		756	events while doing lengthy calculations, to keep the program responsive.
726		757
727	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	758	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
728	necessary) and will handle those and any already outstanding ones. It	759	necessary) and will handle those and any already outstanding ones. It
729	will block your process until at least one new event arrives (which could	760	will block your process until at least one new event arrives (which could
730	be an event internal to libev itself, so there is no guarantee that a	761	be an event internal to libev itself, so there is no guarantee that a
731	user-registered callback will be called), and will return after one	762	user-registered callback will be called), and will return after one
732	iteration of the loop.	763	iteration of the loop.
733		764
734	This is useful if you are waiting for some external event in conjunction	765	This is useful if you are waiting for some external event in conjunction
735	with something not expressible using other libev watchers (i.e. "roll your	766	with something not expressible using other libev watchers (i.e. "roll your
736	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	767	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
737	usually a better approach for this kind of thing.	768	usually a better approach for this kind of thing.
738		769
739	Here are the gory details of what C<ev_loop> does:	770	Here are the gory details of what C<ev_run> does:
740		771
		772	- Increment loop depth.
		773	- Reset the ev_break status.
741	- Before the first iteration, call any pending watchers.	774	- Before the first iteration, call any pending watchers.
		775	LOOP:
742	* If EVFLAG_FORKCHECK was used, check for a fork.	776	- If EVFLAG_FORKCHECK was used, check for a fork.
743	- If a fork was detected (by any means), queue and call all fork watchers.	777	- If a fork was detected (by any means), queue and call all fork watchers.
744	- Queue and call all prepare watchers.	778	- Queue and call all prepare watchers.
		779	- If ev_break was called, goto FINISH.
745	- If we have been forked, detach and recreate the kernel state	780	- If we have been forked, detach and recreate the kernel state
746	as to not disturb the other process.	781	as to not disturb the other process.
747	- Update the kernel state with all outstanding changes.	782	- Update the kernel state with all outstanding changes.
748	- Update the "event loop time" (ev_now ()).	783	- Update the "event loop time" (ev_now ()).
749	- Calculate for how long to sleep or block, if at all	784	- Calculate for how long to sleep or block, if at all
750	(active idle watchers, EVLOOP_NONBLOCK or not having	785	(active idle watchers, EVRUN_NOWAIT or not having
751	any active watchers at all will result in not sleeping).	786	any active watchers at all will result in not sleeping).
752	- Sleep if the I/O and timer collect interval say so.	787	- Sleep if the I/O and timer collect interval say so.
		788	- Increment loop iteration counter.
753	- Block the process, waiting for any events.	789	- Block the process, waiting for any events.
754	- Queue all outstanding I/O (fd) events.	790	- Queue all outstanding I/O (fd) events.
755	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	791	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
756	- Queue all expired timers.	792	- Queue all expired timers.
757	- Queue all expired periodics.	793	- Queue all expired periodics.
758	- Unless any events are pending now, queue all idle watchers.	794	- Queue all idle watchers with priority higher than that of pending events.
759	- Queue all check watchers.	795	- Queue all check watchers.
760	- Call all queued watchers in reverse order (i.e. check watchers first).	796	- Call all queued watchers in reverse order (i.e. check watchers first).
761	Signals and child watchers are implemented as I/O watchers, and will	797	Signals and child watchers are implemented as I/O watchers, and will
762	be handled here by queueing them when their watcher gets executed.	798	be handled here by queueing them when their watcher gets executed.
763	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	799	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
764	were used, or there are no active watchers, return, otherwise	800	were used, or there are no active watchers, goto FINISH, otherwise
765	continue with step *.	801	continue with step LOOP.
		802	FINISH:
		803	- Reset the ev_break status iff it was EVBREAK_ONE.
		804	- Decrement the loop depth.
		805	- Return.
766		806
767	Example: Queue some jobs and then loop until no events are outstanding	807	Example: Queue some jobs and then loop until no events are outstanding
768	anymore.	808	anymore.
769		809
770	... queue jobs here, make sure they register event watchers as long	810	... queue jobs here, make sure they register event watchers as long
771	... as they still have work to do (even an idle watcher will do..)	811	... as they still have work to do (even an idle watcher will do..)
772	ev_loop (my_loop, 0);	812	ev_run (my_loop, 0);
773	... jobs done or somebody called unloop. yeah!	813	... jobs done or somebody called unloop. yeah!
774		814
775	=item ev_unloop (loop, how)	815	=item ev_break (loop, how)
776		816
777	Can be used to make a call to C<ev_loop> return early (but only after it	817	Can be used to make a call to C<ev_run> return early (but only after it
778	has processed all outstanding events). The C<how> argument must be either	818	has processed all outstanding events). The C<how> argument must be either
779	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	819	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
780	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	820	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
781		821
782	This "unloop state" will be cleared when entering C<ev_loop> again.	822	This "unloop state" will be cleared when entering C<ev_run> again.
783		823
784	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	824	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
785		825
786	=item ev_ref (loop)	826	=item ev_ref (loop)
787		827
788	=item ev_unref (loop)	828	=item ev_unref (loop)
789		829
790	Ref/unref can be used to add or remove a reference count on the event	830	Ref/unref can be used to add or remove a reference count on the event
791	loop: Every watcher keeps one reference, and as long as the reference	831	loop: Every watcher keeps one reference, and as long as the reference
792	count is nonzero, C<ev_loop> will not return on its own.	832	count is nonzero, C<ev_run> will not return on its own.
793		833
794	If you have a watcher you never unregister that should not keep C<ev_loop>	834	This is useful when you have a watcher that you never intend to
795	from returning, call ev_unref() after starting, and ev_ref() before	835	unregister, but that nevertheless should not keep C<ev_run> from
		836	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
796	stopping it.	837	before stopping it.
797		838
798	As an example, libev itself uses this for its internal signal pipe: It	839	As an example, libev itself uses this for its internal signal pipe: It
799	is not visible to the libev user and should not keep C<ev_loop> from	840	is not visible to the libev user and should not keep C<ev_run> from
800	exiting if no event watchers registered by it are active. It is also an	841	exiting if no event watchers registered by it are active. It is also an
801	excellent way to do this for generic recurring timers or from within	842	excellent way to do this for generic recurring timers or from within
802	third-party libraries. Just remember to I<unref after start> and I<ref	843	third-party libraries. Just remember to I<unref after start> and I<ref
803	before stop> (but only if the watcher wasn't active before, or was active	844	before stop> (but only if the watcher wasn't active before, or was active
804	before, respectively. Note also that libev might stop watchers itself	845	before, respectively. Note also that libev might stop watchers itself
805	(e.g. non-repeating timers) in which case you have to C<ev_ref>	846	(e.g. non-repeating timers) in which case you have to C<ev_ref>
806	in the callback).	847	in the callback).
807		848
808	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	849	Example: Create a signal watcher, but keep it from keeping C<ev_run>
809	running when nothing else is active.	850	running when nothing else is active.
810		851
811	ev_signal exitsig;	852	ev_signal exitsig;
812	ev_signal_init (&exitsig, sig_cb, SIGINT);	853	ev_signal_init (&exitsig, sig_cb, SIGINT);
813	ev_signal_start (loop, &exitsig);	854	ev_signal_start (loop, &exitsig);
…		…
858	usually doesn't make much sense to set it to a lower value than C<0.01>,	899	usually doesn't make much sense to set it to a lower value than C<0.01>,
859	as this approaches the timing granularity of most systems. Note that if	900	as this approaches the timing granularity of most systems. Note that if
860	you do transactions with the outside world and you can't increase the	901	you do transactions with the outside world and you can't increase the
861	parallelity, then this setting will limit your transaction rate (if you	902	parallelity, then this setting will limit your transaction rate (if you
862	need to poll once per transaction and the I/O collect interval is 0.01,	903	need to poll once per transaction and the I/O collect interval is 0.01,
863	then you can't do more than 100 transations per second).	904	then you can't do more than 100 transactions per second).
864		905
865	Setting the I<timeout collect interval> can improve the opportunity for	906	Setting the I<timeout collect interval> can improve the opportunity for
866	saving power, as the program will "bundle" timer callback invocations that	907	saving power, as the program will "bundle" timer callback invocations that
867	are "near" in time together, by delaying some, thus reducing the number of	908	are "near" in time together, by delaying some, thus reducing the number of
868	times the process sleeps and wakes up again. Another useful technique to	909	times the process sleeps and wakes up again. Another useful technique to
…		…
876	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	917	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
877		918
878	=item ev_invoke_pending (loop)	919	=item ev_invoke_pending (loop)
879		920
880	This call will simply invoke all pending watchers while resetting their	921	This call will simply invoke all pending watchers while resetting their
881	pending state. Normally, C<ev_loop> does this automatically when required,	922	pending state. Normally, C<ev_run> does this automatically when required,
882	but when overriding the invoke callback this call comes handy.	923	but when overriding the invoke callback this call comes handy. This
		924	function can be invoked from a watcher - this can be useful for example
		925	when you want to do some lengthy calculation and want to pass further
		926	event handling to another thread (you still have to make sure only one
		927	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
883		928
884	=item int ev_pending_count (loop)	929	=item int ev_pending_count (loop)
885		930
886	Returns the number of pending watchers - zero indicates that no watchers	931	Returns the number of pending watchers - zero indicates that no watchers
887	are pending.	932	are pending.
888		933
889	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	934	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
890		935
891	This overrides the invoke pending functionality of the loop: Instead of	936	This overrides the invoke pending functionality of the loop: Instead of
892	invoking all pending watchers when there are any, C<ev_loop> will call	937	invoking all pending watchers when there are any, C<ev_run> will call
893	this callback instead. This is useful, for example, when you want to	938	this callback instead. This is useful, for example, when you want to
894	invoke the actual watchers inside another context (another thread etc.).	939	invoke the actual watchers inside another context (another thread etc.).
895		940
896	If you want to reset the callback, use C<ev_invoke_pending> as new	941	If you want to reset the callback, use C<ev_invoke_pending> as new
897	callback.	942	callback.
…		…
900		945
901	Sometimes you want to share the same loop between multiple threads. This	946	Sometimes you want to share the same loop between multiple threads. This
902	can be done relatively simply by putting mutex_lock/unlock calls around	947	can be done relatively simply by putting mutex_lock/unlock calls around
903	each call to a libev function.	948	each call to a libev function.
904		949
905	However, C<ev_loop> can run an indefinite time, so it is not feasible to	950	However, C<ev_run> can run an indefinite time, so it is not feasible
906	wait for it to return. One way around this is to wake up the loop via	951	to wait for it to return. One way around this is to wake up the event
907	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	952	loop via C<ev_break> and C<av_async_send>, another way is to set these
908	and I<acquire> callbacks on the loop.	953	I<release> and I<acquire> callbacks on the loop.
909		954
910	When set, then C<release> will be called just before the thread is	955	When set, then C<release> will be called just before the thread is
911	suspended waiting for new events, and C<acquire> is called just	956	suspended waiting for new events, and C<acquire> is called just
912	afterwards.	957	afterwards.
913		958
…		…
916		961
917	While event loop modifications are allowed between invocations of	962	While event loop modifications are allowed between invocations of
918	C<release> and C<acquire> (that's their only purpose after all), no	963	C<release> and C<acquire> (that's their only purpose after all), no
919	modifications done will affect the event loop, i.e. adding watchers will	964	modifications done will affect the event loop, i.e. adding watchers will
920	have no effect on the set of file descriptors being watched, or the time	965	have no effect on the set of file descriptors being watched, or the time
921	waited. USe an C<ev_async> watcher to wake up C<ev_loop> when you want it	966	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
922	to take note of any changes you made.	967	to take note of any changes you made.
923		968
924	In theory, threads executing C<ev_loop> will be async-cancel safe between	969	In theory, threads executing C<ev_run> will be async-cancel safe between
925	invocations of C<release> and C<acquire>.	970	invocations of C<release> and C<acquire>.
926		971
927	See also the locking example in the C<THREADS> section later in this	972	See also the locking example in the C<THREADS> section later in this
928	document.	973	document.
929		974
…		…
938	These two functions can be used to associate arbitrary data with a loop,	983	These two functions can be used to associate arbitrary data with a loop,
939	and are intended solely for the C<invoke_pending_cb>, C<release> and	984	and are intended solely for the C<invoke_pending_cb>, C<release> and
940	C<acquire> callbacks described above, but of course can be (ab-)used for	985	C<acquire> callbacks described above, but of course can be (ab-)used for
941	any other purpose as well.	986	any other purpose as well.
942		987
943	=item ev_loop_verify (loop)	988	=item ev_verify (loop)
944		989
945	This function only does something when C<EV_VERIFY> support has been	990	This function only does something when C<EV_VERIFY> support has been
946	compiled in, which is the default for non-minimal builds. It tries to go	991	compiled in, which is the default for non-minimal builds. It tries to go
947	through all internal structures and checks them for validity. If anything	992	through all internal structures and checks them for validity. If anything
948	is found to be inconsistent, it will print an error message to standard	993	is found to be inconsistent, it will print an error message to standard
…		…
959		1004
960	In the following description, uppercase C<TYPE> in names stands for the	1005	In the following description, uppercase C<TYPE> in names stands for the
961	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1006	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
962	watchers and C<ev_io_start> for I/O watchers.	1007	watchers and C<ev_io_start> for I/O watchers.
963		1008
964	A watcher is a structure that you create and register to record your	1009	A watcher is an opaque structure that you allocate and register to record
965	interest in some event. For instance, if you want to wait for STDIN to	1010	your interest in some event. To make a concrete example, imagine you want
966	become readable, you would create an C<ev_io> watcher for that:	1011	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1012	for that:
967		1013
968	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1014	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
969	{	1015	{
970	ev_io_stop (w);	1016	ev_io_stop (w);
971	ev_unloop (loop, EVUNLOOP_ALL);	1017	ev_break (loop, EVBREAK_ALL);
972	}	1018	}
973		1019
974	struct ev_loop *loop = ev_default_loop (0);	1020	struct ev_loop *loop = ev_default_loop (0);
975		1021
976	ev_io stdin_watcher;	1022	ev_io stdin_watcher;
977		1023
978	ev_init (&stdin_watcher, my_cb);	1024	ev_init (&stdin_watcher, my_cb);
979	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1025	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
980	ev_io_start (loop, &stdin_watcher);	1026	ev_io_start (loop, &stdin_watcher);
981		1027
982	ev_loop (loop, 0);	1028	ev_run (loop, 0);
983		1029
984	As you can see, you are responsible for allocating the memory for your	1030	As you can see, you are responsible for allocating the memory for your
985	watcher structures (and it is I<usually> a bad idea to do this on the	1031	watcher structures (and it is I<usually> a bad idea to do this on the
986	stack).	1032	stack).
987		1033
988	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1034	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
989	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1035	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
990		1036
991	Each watcher structure must be initialised by a call to C<ev_init	1037	Each watcher structure must be initialised by a call to C<ev_init (watcher
992	(watcher *, callback)>, which expects a callback to be provided. This	1038	*, callback)>, which expects a callback to be provided. This callback is
993	callback gets invoked each time the event occurs (or, in the case of I/O	1039	invoked each time the event occurs (or, in the case of I/O watchers, each
994	watchers, each time the event loop detects that the file descriptor given	1040	time the event loop detects that the file descriptor given is readable
995	is readable and/or writable).	1041	and/or writable).
996		1042
997	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1043	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
998	macro to configure it, with arguments specific to the watcher type. There	1044	macro to configure it, with arguments specific to the watcher type. There
999	is also a macro to combine initialisation and setting in one call: C<<	1045	is also a macro to combine initialisation and setting in one call: C<<
1000	ev_TYPE_init (watcher *, callback, ...) >>.	1046	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1023	=item C<EV_WRITE>	1069	=item C<EV_WRITE>
1024		1070
1025	The file descriptor in the C<ev_io> watcher has become readable and/or	1071	The file descriptor in the C<ev_io> watcher has become readable and/or
1026	writable.	1072	writable.
1027		1073
1028	=item C<EV_TIMEOUT>	1074	=item C<EV_TIMER>
1029		1075
1030	The C<ev_timer> watcher has timed out.	1076	The C<ev_timer> watcher has timed out.
1031		1077
1032	=item C<EV_PERIODIC>	1078	=item C<EV_PERIODIC>
1033		1079
…		…
1051		1097
1052	=item C<EV_PREPARE>	1098	=item C<EV_PREPARE>
1053		1099
1054	=item C<EV_CHECK>	1100	=item C<EV_CHECK>
1055		1101
1056	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1102	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1057	to gather new events, and all C<ev_check> watchers are invoked just after	1103	to gather new events, and all C<ev_check> watchers are invoked just after
1058	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1104	C<ev_run> has gathered them, but before it invokes any callbacks for any
1059	received events. Callbacks of both watcher types can start and stop as	1105	received events. Callbacks of both watcher types can start and stop as
1060	many watchers as they want, and all of them will be taken into account	1106	many watchers as they want, and all of them will be taken into account
1061	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1107	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1062	C<ev_loop> from blocking).	1108	C<ev_run> from blocking).
1063		1109
1064	=item C<EV_EMBED>	1110	=item C<EV_EMBED>
1065		1111
1066	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1112	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1067		1113
…		…
1098	programs, though, as the fd could already be closed and reused for another	1144	programs, though, as the fd could already be closed and reused for another
1099	thing, so beware.	1145	thing, so beware.
1100		1146
1101	=back	1147	=back
1102		1148
		1149	=head2 WATCHER STATES
		1150
		1151	There are various watcher states mentioned throughout this manual -
		1152	active, pending and so on. In this section these states and the rules to
		1153	transition between them will be described in more detail - and while these
		1154	rules might look complicated, they usually do "the right thing".
		1155
		1156	=over 4
		1157
		1158	=item initialiased
		1159
		1160	Before a watcher can be registered with the event looop it has to be
		1161	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1162	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1163
		1164	In this state it is simply some block of memory that is suitable for use
		1165	in an event loop. It can be moved around, freed, reused etc. at will.
		1166
		1167	=item started/running/active
		1168
		1169	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1170	property of the event loop, and is actively waiting for events. While in
		1171	this state it cannot be accessed (except in a few documented ways), moved,
		1172	freed or anything else - the only legal thing is to keep a pointer to it,
		1173	and call libev functions on it that are documented to work on active watchers.
		1174
		1175	=item pending
		1176
		1177	If a watcher is active and libev determines that an event it is interested
		1178	in has occurred (such as a timer expiring), it will become pending. It will
		1179	stay in this pending state until either it is stopped or its callback is
		1180	about to be invoked, so it is not normally pending inside the watcher
		1181	callback.
		1182
		1183	The watcher might or might not be active while it is pending (for example,
		1184	an expired non-repeating timer can be pending but no longer active). If it
		1185	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1186	but it is still property of the event loop at this time, so cannot be
		1187	moved, freed or reused. And if it is active the rules described in the
		1188	previous item still apply.
		1189
		1190	It is also possible to feed an event on a watcher that is not active (e.g.
		1191	via C<ev_feed_event>), in which case it becomes pending without being
		1192	active.
		1193
		1194	=item stopped
		1195
		1196	A watcher can be stopped implicitly by libev (in which case it might still
		1197	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1198	latter will clear any pending state the watcher might be in, regardless
		1199	of whether it was active or not, so stopping a watcher explicitly before
		1200	freeing it is often a good idea.
		1201
		1202	While stopped (and not pending) the watcher is essentially in the
		1203	initialised state, that is it can be reused, moved, modified in any way
		1204	you wish.
		1205
		1206	=back
		1207
1103	=head2 GENERIC WATCHER FUNCTIONS	1208	=head2 GENERIC WATCHER FUNCTIONS
1104		1209
1105	=over 4	1210	=over 4
1106		1211
1107	=item C<ev_init> (ev_TYPE *watcher, callback)	1212	=item C<ev_init> (ev_TYPE *watcher, callback)
…		…
1123		1228
1124	ev_io w;	1229	ev_io w;
1125	ev_init (&w, my_cb);	1230	ev_init (&w, my_cb);
1126	ev_io_set (&w, STDIN_FILENO, EV_READ);	1231	ev_io_set (&w, STDIN_FILENO, EV_READ);
1127		1232
1128	=item C<ev_TYPE_set> (ev_TYPE *, [args])	1233	=item C<ev_TYPE_set> (ev_TYPE *watcher, [args])
1129		1234
1130	This macro initialises the type-specific parts of a watcher. You need to	1235	This macro initialises the type-specific parts of a watcher. You need to
1131	call C<ev_init> at least once before you call this macro, but you can	1236	call C<ev_init> at least once before you call this macro, but you can
1132	call C<ev_TYPE_set> any number of times. You must not, however, call this	1237	call C<ev_TYPE_set> any number of times. You must not, however, call this
1133	macro on a watcher that is active (it can be pending, however, which is a	1238	macro on a watcher that is active (it can be pending, however, which is a
…		…
1146		1251
1147	Example: Initialise and set an C<ev_io> watcher in one step.	1252	Example: Initialise and set an C<ev_io> watcher in one step.
1148		1253
1149	ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);	1254	ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
1150		1255
1151	=item C<ev_TYPE_start> (loop *, ev_TYPE *watcher)	1256	=item C<ev_TYPE_start> (loop, ev_TYPE *watcher)
1152		1257
1153	Starts (activates) the given watcher. Only active watchers will receive	1258	Starts (activates) the given watcher. Only active watchers will receive
1154	events. If the watcher is already active nothing will happen.	1259	events. If the watcher is already active nothing will happen.
1155		1260
1156	Example: Start the C<ev_io> watcher that is being abused as example in this	1261	Example: Start the C<ev_io> watcher that is being abused as example in this
1157	whole section.	1262	whole section.
1158		1263
1159	ev_io_start (EV_DEFAULT_UC, &w);	1264	ev_io_start (EV_DEFAULT_UC, &w);
1160		1265
1161	=item C<ev_TYPE_stop> (loop *, ev_TYPE *watcher)	1266	=item C<ev_TYPE_stop> (loop, ev_TYPE *watcher)
1162		1267
1163	Stops the given watcher if active, and clears the pending status (whether	1268	Stops the given watcher if active, and clears the pending status (whether
1164	the watcher was active or not).	1269	the watcher was active or not).
1165		1270
1166	It is possible that stopped watchers are pending - for example,	1271	It is possible that stopped watchers are pending - for example,
…		…
1191	=item ev_cb_set (ev_TYPE *watcher, callback)	1296	=item ev_cb_set (ev_TYPE *watcher, callback)
1192		1297
1193	Change the callback. You can change the callback at virtually any time	1298	Change the callback. You can change the callback at virtually any time
1194	(modulo threads).	1299	(modulo threads).
1195		1300
1196	=item ev_set_priority (ev_TYPE *watcher, priority)	1301	=item ev_set_priority (ev_TYPE *watcher, int priority)
1197		1302
1198	=item int ev_priority (ev_TYPE *watcher)	1303	=item int ev_priority (ev_TYPE *watcher)
1199		1304
1200	Set and query the priority of the watcher. The priority is a small	1305	Set and query the priority of the watcher. The priority is a small
1201	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>	1306	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
…		…
1232	returns its C<revents> bitset (as if its callback was invoked). If the	1337	returns its C<revents> bitset (as if its callback was invoked). If the
1233	watcher isn't pending it does nothing and returns C<0>.	1338	watcher isn't pending it does nothing and returns C<0>.
1234		1339
1235	Sometimes it can be useful to "poll" a watcher instead of waiting for its	1340	Sometimes it can be useful to "poll" a watcher instead of waiting for its
1236	callback to be invoked, which can be accomplished with this function.	1341	callback to be invoked, which can be accomplished with this function.
		1342
		1343	=item ev_feed_event (loop, ev_TYPE *watcher, int revents)
		1344
		1345	Feeds the given event set into the event loop, as if the specified event
		1346	had happened for the specified watcher (which must be a pointer to an
		1347	initialised but not necessarily started event watcher). Obviously you must
		1348	not free the watcher as long as it has pending events.
		1349
		1350	Stopping the watcher, letting libev invoke it, or calling
		1351	C<ev_clear_pending> will clear the pending event, even if the watcher was
		1352	not started in the first place.
		1353
		1354	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
		1355	functions that do not need a watcher.
1237		1356
1238	=back	1357	=back
1239		1358
1240		1359
1241	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1360	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
1352		1471
1353	For example, to emulate how many other event libraries handle priorities,	1472	For example, to emulate how many other event libraries handle priorities,
1354	you can associate an C<ev_idle> watcher to each such watcher, and in	1473	you can associate an C<ev_idle> watcher to each such watcher, and in
1355	the normal watcher callback, you just start the idle watcher. The real	1474	the normal watcher callback, you just start the idle watcher. The real
1356	processing is done in the idle watcher callback. This causes libev to	1475	processing is done in the idle watcher callback. This causes libev to
1357	continously poll and process kernel event data for the watcher, but when	1476	continuously poll and process kernel event data for the watcher, but when
1358	the lock-out case is known to be rare (which in turn is rare :), this is	1477	the lock-out case is known to be rare (which in turn is rare :), this is
1359	workable.	1478	workable.
1360		1479
1361	Usually, however, the lock-out model implemented that way will perform	1480	Usually, however, the lock-out model implemented that way will perform
1362	miserably under the type of load it was designed to handle. In that case,	1481	miserably under the type of load it was designed to handle. In that case,
…		…
1376	{	1495	{
1377	// stop the I/O watcher, we received the event, but	1496	// stop the I/O watcher, we received the event, but
1378	// are not yet ready to handle it.	1497	// are not yet ready to handle it.
1379	ev_io_stop (EV_A_ w);	1498	ev_io_stop (EV_A_ w);
1380		1499
1381	// start the idle watcher to ahndle the actual event.	1500	// start the idle watcher to handle the actual event.
1382	// it will not be executed as long as other watchers	1501	// it will not be executed as long as other watchers
1383	// with the default priority are receiving events.	1502	// with the default priority are receiving events.
1384	ev_idle_start (EV_A_ &idle);	1503	ev_idle_start (EV_A_ &idle);
1385	}	1504	}
1386		1505
…		…
1440		1559
1441	If you cannot use non-blocking mode, then force the use of a	1560	If you cannot use non-blocking mode, then force the use of a
1442	known-to-be-good backend (at the time of this writing, this includes only	1561	known-to-be-good backend (at the time of this writing, this includes only
1443	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1562	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1444	descriptors for which non-blocking operation makes no sense (such as	1563	descriptors for which non-blocking operation makes no sense (such as
1445	files) - libev doesn't guarentee any specific behaviour in that case.	1564	files) - libev doesn't guarantee any specific behaviour in that case.
1446		1565
1447	Another thing you have to watch out for is that it is quite easy to	1566	Another thing you have to watch out for is that it is quite easy to
1448	receive "spurious" readiness notifications, that is your callback might	1567	receive "spurious" readiness notifications, that is your callback might
1449	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1568	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1450	because there is no data. Not only are some backends known to create a	1569	because there is no data. Not only are some backends known to create a
…		…
1515		1634
1516	So when you encounter spurious, unexplained daemon exits, make sure you	1635	So when you encounter spurious, unexplained daemon exits, make sure you
1517	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1636	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1518	somewhere, as that would have given you a big clue).	1637	somewhere, as that would have given you a big clue).
1519		1638
		1639	=head3 The special problem of accept()ing when you can't
		1640
		1641	Many implementations of the POSIX C<accept> function (for example,
		1642	found in post-2004 Linux) have the peculiar behaviour of not removing a
		1643	connection from the pending queue in all error cases.
		1644
		1645	For example, larger servers often run out of file descriptors (because
		1646	of resource limits), causing C<accept> to fail with C<ENFILE> but not
		1647	rejecting the connection, leading to libev signalling readiness on
		1648	the next iteration again (the connection still exists after all), and
		1649	typically causing the program to loop at 100% CPU usage.
		1650
		1651	Unfortunately, the set of errors that cause this issue differs between
		1652	operating systems, there is usually little the app can do to remedy the
		1653	situation, and no known thread-safe method of removing the connection to
		1654	cope with overload is known (to me).
		1655
		1656	One of the easiest ways to handle this situation is to just ignore it
		1657	- when the program encounters an overload, it will just loop until the
		1658	situation is over. While this is a form of busy waiting, no OS offers an
		1659	event-based way to handle this situation, so it's the best one can do.
		1660
		1661	A better way to handle the situation is to log any errors other than
		1662	C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
		1663	messages, and continue as usual, which at least gives the user an idea of
		1664	what could be wrong ("raise the ulimit!"). For extra points one could stop
		1665	the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
		1666	usage.
		1667
		1668	If your program is single-threaded, then you could also keep a dummy file
		1669	descriptor for overload situations (e.g. by opening F</dev/null>), and
		1670	when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
		1671	close that fd, and create a new dummy fd. This will gracefully refuse
		1672	clients under typical overload conditions.
		1673
		1674	The last way to handle it is to simply log the error and C<exit>, as
		1675	is often done with C<malloc> failures, but this results in an easy
		1676	opportunity for a DoS attack.
1520		1677
1521	=head3 Watcher-Specific Functions	1678	=head3 Watcher-Specific Functions
1522		1679
1523	=over 4	1680	=over 4
1524		1681
…		…
1556	...	1713	...
1557	struct ev_loop *loop = ev_default_init (0);	1714	struct ev_loop *loop = ev_default_init (0);
1558	ev_io stdin_readable;	1715	ev_io stdin_readable;
1559	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1716	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1560	ev_io_start (loop, &stdin_readable);	1717	ev_io_start (loop, &stdin_readable);
1561	ev_loop (loop, 0);	1718	ev_run (loop, 0);
1562		1719
1563		1720
1564	=head2 C<ev_timer> - relative and optionally repeating timeouts	1721	=head2 C<ev_timer> - relative and optionally repeating timeouts
1565		1722
1566	Timer watchers are simple relative timers that generate an event after a	1723	Timer watchers are simple relative timers that generate an event after a
…		…
1575	The callback is guaranteed to be invoked only I<after> its timeout has	1732	The callback is guaranteed to be invoked only I<after> its timeout has
1576	passed (not I<at>, so on systems with very low-resolution clocks this	1733	passed (not I<at>, so on systems with very low-resolution clocks this
1577	might introduce a small delay). If multiple timers become ready during the	1734	might introduce a small delay). If multiple timers become ready during the
1578	same loop iteration then the ones with earlier time-out values are invoked	1735	same loop iteration then the ones with earlier time-out values are invoked
1579	before ones of the same priority with later time-out values (but this is	1736	before ones of the same priority with later time-out values (but this is
1580	no longer true when a callback calls C<ev_loop> recursively).	1737	no longer true when a callback calls C<ev_run> recursively).
1581		1738
1582	=head3 Be smart about timeouts	1739	=head3 Be smart about timeouts
1583		1740
1584	Many real-world problems involve some kind of timeout, usually for error	1741	Many real-world problems involve some kind of timeout, usually for error
1585	recovery. A typical example is an HTTP request - if the other side hangs,	1742	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1671	ev_tstamp timeout = last_activity + 60.;	1828	ev_tstamp timeout = last_activity + 60.;
1672		1829
1673	// if last_activity + 60. is older than now, we did time out	1830	// if last_activity + 60. is older than now, we did time out
1674	if (timeout < now)	1831	if (timeout < now)
1675	{	1832	{
1676	// timeout occured, take action	1833	// timeout occurred, take action
1677	}	1834	}
1678	else	1835	else
1679	{	1836	{
1680	// callback was invoked, but there was some activity, re-arm	1837	// callback was invoked, but there was some activity, re-arm
1681	// the watcher to fire in last_activity + 60, which is	1838	// the watcher to fire in last_activity + 60, which is
…		…
1703	to the current time (meaning we just have some activity :), then call the	1860	to the current time (meaning we just have some activity :), then call the
1704	callback, which will "do the right thing" and start the timer:	1861	callback, which will "do the right thing" and start the timer:
1705		1862
1706	ev_init (timer, callback);	1863	ev_init (timer, callback);
1707	last_activity = ev_now (loop);	1864	last_activity = ev_now (loop);
1708	callback (loop, timer, EV_TIMEOUT);	1865	callback (loop, timer, EV_TIMER);
1709		1866
1710	And when there is some activity, simply store the current time in	1867	And when there is some activity, simply store the current time in
1711	C<last_activity>, no libev calls at all:	1868	C<last_activity>, no libev calls at all:
1712		1869
1713	last_actiivty = ev_now (loop);	1870	last_activity = ev_now (loop);
1714		1871
1715	This technique is slightly more complex, but in most cases where the	1872	This technique is slightly more complex, but in most cases where the
1716	time-out is unlikely to be triggered, much more efficient.	1873	time-out is unlikely to be triggered, much more efficient.
1717		1874
1718	Changing the timeout is trivial as well (if it isn't hard-coded in the	1875	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1756		1913
1757	=head3 The special problem of time updates	1914	=head3 The special problem of time updates
1758		1915
1759	Establishing the current time is a costly operation (it usually takes at	1916	Establishing the current time is a costly operation (it usually takes at
1760	least two system calls): EV therefore updates its idea of the current	1917	least two system calls): EV therefore updates its idea of the current
1761	time only before and after C<ev_loop> collects new events, which causes a	1918	time only before and after C<ev_run> collects new events, which causes a
1762	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1919	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1763	lots of events in one iteration.	1920	lots of events in one iteration.
1764		1921
1765	The relative timeouts are calculated relative to the C<ev_now ()>	1922	The relative timeouts are calculated relative to the C<ev_now ()>
1766	time. This is usually the right thing as this timestamp refers to the time	1923	time. This is usually the right thing as this timestamp refers to the time
…		…
1837	C<repeat> value), or reset the running timer to the C<repeat> value.	1994	C<repeat> value), or reset the running timer to the C<repeat> value.
1838		1995
1839	This sounds a bit complicated, see L<Be smart about timeouts>, above, for a	1996	This sounds a bit complicated, see L<Be smart about timeouts>, above, for a
1840	usage example.	1997	usage example.
1841		1998
1842	=item ev_timer_remaining (loop, ev_timer *)	1999	=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
1843		2000
1844	Returns the remaining time until a timer fires. If the timer is active,	2001	Returns the remaining time until a timer fires. If the timer is active,
1845	then this time is relative to the current event loop time, otherwise it's	2002	then this time is relative to the current event loop time, otherwise it's
1846	the timeout value currently configured.	2003	the timeout value currently configured.
1847		2004
1848	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns	2005	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
1849	C<5>. When the timer is started and one second passes, C<ev_timer_remain>	2006	C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
1850	will return C<4>. When the timer expires and is restarted, it will return	2007	will return C<4>. When the timer expires and is restarted, it will return
1851	roughly C<7> (likely slightly less as callback invocation takes some time,	2008	roughly C<7> (likely slightly less as callback invocation takes some time,
1852	too), and so on.	2009	too), and so on.
1853		2010
1854	=item ev_tstamp repeat [read-write]	2011	=item ev_tstamp repeat [read-write]
…		…
1883	}	2040	}
1884		2041
1885	ev_timer mytimer;	2042	ev_timer mytimer;
1886	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2043	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1887	ev_timer_again (&mytimer); /* start timer */	2044	ev_timer_again (&mytimer); /* start timer */
1888	ev_loop (loop, 0);	2045	ev_run (loop, 0);
1889		2046
1890	// and in some piece of code that gets executed on any "activity":	2047	// and in some piece of code that gets executed on any "activity":
1891	// reset the timeout to start ticking again at 10 seconds	2048	// reset the timeout to start ticking again at 10 seconds
1892	ev_timer_again (&mytimer);	2049	ev_timer_again (&mytimer);
1893		2050
…		…
1919		2076
1920	As with timers, the callback is guaranteed to be invoked only when the	2077	As with timers, the callback is guaranteed to be invoked only when the
1921	point in time where it is supposed to trigger has passed. If multiple	2078	point in time where it is supposed to trigger has passed. If multiple
1922	timers become ready during the same loop iteration then the ones with	2079	timers become ready during the same loop iteration then the ones with
1923	earlier time-out values are invoked before ones with later time-out values	2080	earlier time-out values are invoked before ones with later time-out values
1924	(but this is no longer true when a callback calls C<ev_loop> recursively).	2081	(but this is no longer true when a callback calls C<ev_run> recursively).
1925		2082
1926	=head3 Watcher-Specific Functions and Data Members	2083	=head3 Watcher-Specific Functions and Data Members
1927		2084
1928	=over 4	2085	=over 4
1929		2086
…		…
2057	Example: Call a callback every hour, or, more precisely, whenever the	2214	Example: Call a callback every hour, or, more precisely, whenever the
2058	system time is divisible by 3600. The callback invocation times have	2215	system time is divisible by 3600. The callback invocation times have
2059	potentially a lot of jitter, but good long-term stability.	2216	potentially a lot of jitter, but good long-term stability.
2060		2217
2061	static void	2218	static void
2062	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2219	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
2063	{	2220	{
2064	... its now a full hour (UTC, or TAI or whatever your clock follows)	2221	... its now a full hour (UTC, or TAI or whatever your clock follows)
2065	}	2222	}
2066		2223
2067	ev_periodic hourly_tick;	2224	ev_periodic hourly_tick;
…		…
2114	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should	2271	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
2115	not be unduly interrupted. If you have a problem with system calls getting	2272	not be unduly interrupted. If you have a problem with system calls getting
2116	interrupted by signals you can block all signals in an C<ev_check> watcher	2273	interrupted by signals you can block all signals in an C<ev_check> watcher
2117	and unblock them in an C<ev_prepare> watcher.	2274	and unblock them in an C<ev_prepare> watcher.
2118		2275
2119	=head3 The special problem of inheritance over execve	2276	=head3 The special problem of inheritance over fork/execve/pthread_create
2120		2277
2121	Both the signal mask (C<sigprocmask>) and the signal disposition	2278	Both the signal mask (C<sigprocmask>) and the signal disposition
2122	(C<sigaction>) are unspecified after starting a signal watcher (and after	2279	(C<sigaction>) are unspecified after starting a signal watcher (and after
2123	stopping it again), that is, libev might or might not block the signal,	2280	stopping it again), that is, libev might or might not block the signal,
2124	and might or might not set or restore the installed signal handler.	2281	and might or might not set or restore the installed signal handler.
2125		2282
2126	While this does not matter for the signal disposition (libev never	2283	While this does not matter for the signal disposition (libev never
2127	sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on	2284	sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on
2128	C<execve>), this matters for the signal mask: many programs do not expect	2285	C<execve>), this matters for the signal mask: many programs do not expect
2129	many signals to be blocked.	2286	certain signals to be blocked.
2130		2287
2131	This means that before calling C<exec> (from the child) you should reset	2288	This means that before calling C<exec> (from the child) you should reset
2132	the signal mask to whatever "default" you expect (all clear is a good	2289	the signal mask to whatever "default" you expect (all clear is a good
2133	choice usually).	2290	choice usually).
2134		2291
		2292	The simplest way to ensure that the signal mask is reset in the child is
		2293	to install a fork handler with C<pthread_atfork> that resets it. That will
		2294	catch fork calls done by libraries (such as the libc) as well.
		2295
		2296	In current versions of libev, the signal will not be blocked indefinitely
		2297	unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
		2298	the window of opportunity for problems, it will not go away, as libev
		2299	I<has> to modify the signal mask, at least temporarily.
		2300
		2301	So I can't stress this enough: I<If you do not reset your signal mask when
		2302	you expect it to be empty, you have a race condition in your code>. This
		2303	is not a libev-specific thing, this is true for most event libraries.
		2304
2135	=head3 Watcher-Specific Functions and Data Members	2305	=head3 Watcher-Specific Functions and Data Members
2136		2306
2137	=over 4	2307	=over 4
2138		2308
2139	=item ev_signal_init (ev_signal *, callback, int signum)	2309	=item ev_signal_init (ev_signal *, callback, int signum)
…		…
2154	Example: Try to exit cleanly on SIGINT.	2324	Example: Try to exit cleanly on SIGINT.
2155		2325
2156	static void	2326	static void
2157	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2327	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2158	{	2328	{
2159	ev_unloop (loop, EVUNLOOP_ALL);	2329	ev_break (loop, EVBREAK_ALL);
2160	}	2330	}
2161		2331
2162	ev_signal signal_watcher;	2332	ev_signal signal_watcher;
2163	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2333	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2164	ev_signal_start (loop, &signal_watcher);	2334	ev_signal_start (loop, &signal_watcher);
…		…
2550		2720
2551	Prepare and check watchers are usually (but not always) used in pairs:	2721	Prepare and check watchers are usually (but not always) used in pairs:
2552	prepare watchers get invoked before the process blocks and check watchers	2722	prepare watchers get invoked before the process blocks and check watchers
2553	afterwards.	2723	afterwards.
2554		2724
2555	You I<must not> call C<ev_loop> or similar functions that enter	2725	You I<must not> call C<ev_run> or similar functions that enter
2556	the current event loop from either C<ev_prepare> or C<ev_check>	2726	the current event loop from either C<ev_prepare> or C<ev_check>
2557	watchers. Other loops than the current one are fine, however. The	2727	watchers. Other loops than the current one are fine, however. The
2558	rationale behind this is that you do not need to check for recursion in	2728	rationale behind this is that you do not need to check for recursion in
2559	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2729	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2560	C<ev_check> so if you have one watcher of each kind they will always be	2730	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2728		2898
2729	if (timeout >= 0)	2899	if (timeout >= 0)
2730	// create/start timer	2900	// create/start timer
2731		2901
2732	// poll	2902	// poll
2733	ev_loop (EV_A_ 0);	2903	ev_run (EV_A_ 0);
2734		2904
2735	// stop timer again	2905	// stop timer again
2736	if (timeout >= 0)	2906	if (timeout >= 0)
2737	ev_timer_stop (EV_A_ &to);	2907	ev_timer_stop (EV_A_ &to);
2738		2908
…		…
2816	if you do not want that, you need to temporarily stop the embed watcher).	2986	if you do not want that, you need to temporarily stop the embed watcher).
2817		2987
2818	=item ev_embed_sweep (loop, ev_embed *)	2988	=item ev_embed_sweep (loop, ev_embed *)
2819		2989
2820	Make a single, non-blocking sweep over the embedded loop. This works	2990	Make a single, non-blocking sweep over the embedded loop. This works
2821	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2991	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2822	appropriate way for embedded loops.	2992	appropriate way for embedded loops.
2823		2993
2824	=item struct ev_loop *other [read-only]	2994	=item struct ev_loop *other [read-only]
2825		2995
2826	The embedded event loop.	2996	The embedded event loop.
…		…
2886	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3056	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2887	handlers will be invoked, too, of course.	3057	handlers will be invoked, too, of course.
2888		3058
2889	=head3 The special problem of life after fork - how is it possible?	3059	=head3 The special problem of life after fork - how is it possible?
2890		3060
2891	Most uses of C<fork()> consist of forking, then some simple calls to ste	3061	Most uses of C<fork()> consist of forking, then some simple calls to set
2892	up/change the process environment, followed by a call to C<exec()>. This	3062	up/change the process environment, followed by a call to C<exec()>. This
2893	sequence should be handled by libev without any problems.	3063	sequence should be handled by libev without any problems.
2894		3064
2895	This changes when the application actually wants to do event handling	3065	This changes when the application actually wants to do event handling
2896	in the child, or both parent in child, in effect "continuing" after the	3066	in the child, or both parent in child, in effect "continuing" after the
…		…
2912	disadvantage of having to use multiple event loops (which do not support	3082	disadvantage of having to use multiple event loops (which do not support
2913	signal watchers).	3083	signal watchers).
2914		3084
2915	When this is not possible, or you want to use the default loop for	3085	When this is not possible, or you want to use the default loop for
2916	other reasons, then in the process that wants to start "fresh", call	3086	other reasons, then in the process that wants to start "fresh", call
2917	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3087	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2918	the default loop will "orphan" (not stop) all registered watchers, so you	3088	Destroying the default loop will "orphan" (not stop) all registered
2919	have to be careful not to execute code that modifies those watchers. Note	3089	watchers, so you have to be careful not to execute code that modifies
2920	also that in that case, you have to re-register any signal watchers.	3090	those watchers. Note also that in that case, you have to re-register any
		3091	signal watchers.
2921		3092
2922	=head3 Watcher-Specific Functions and Data Members	3093	=head3 Watcher-Specific Functions and Data Members
2923		3094
2924	=over 4	3095	=over 4
2925		3096
…		…
2930	believe me.	3101	believe me.
2931		3102
2932	=back	3103	=back
2933		3104
2934		3105
2935	=head2 C<ev_async> - how to wake up another event loop	3106	=head2 C<ev_async> - how to wake up an event loop
2936		3107
2937	In general, you cannot use an C<ev_loop> from multiple threads or other	3108	In general, you cannot use an C<ev_run> from multiple threads or other
2938	asynchronous sources such as signal handlers (as opposed to multiple event	3109	asynchronous sources such as signal handlers (as opposed to multiple event
2939	loops - those are of course safe to use in different threads).	3110	loops - those are of course safe to use in different threads).
2940		3111
2941	Sometimes, however, you need to wake up another event loop you do not	3112	Sometimes, however, you need to wake up an event loop you do not control,
2942	control, for example because it belongs to another thread. This is what	3113	for example because it belongs to another thread. This is what C<ev_async>
2943	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3114	watchers do: as long as the C<ev_async> watcher is active, you can signal
2944	can signal it by calling C<ev_async_send>, which is thread- and signal	3115	it by calling C<ev_async_send>, which is thread- and signal safe.
2945	safe.
2946		3116
2947	This functionality is very similar to C<ev_signal> watchers, as signals,	3117	This functionality is very similar to C<ev_signal> watchers, as signals,
2948	too, are asynchronous in nature, and signals, too, will be compressed	3118	too, are asynchronous in nature, and signals, too, will be compressed
2949	(i.e. the number of callback invocations may be less than the number of	3119	(i.e. the number of callback invocations may be less than the number of
2950	C<ev_async_sent> calls).	3120	C<ev_async_sent> calls).
…		…
2955	=head3 Queueing	3125	=head3 Queueing
2956		3126
2957	C<ev_async> does not support queueing of data in any way. The reason	3127	C<ev_async> does not support queueing of data in any way. The reason
2958	is that the author does not know of a simple (or any) algorithm for a	3128	is that the author does not know of a simple (or any) algorithm for a
2959	multiple-writer-single-reader queue that works in all cases and doesn't	3129	multiple-writer-single-reader queue that works in all cases and doesn't
2960	need elaborate support such as pthreads.	3130	need elaborate support such as pthreads or unportable memory access
		3131	semantics.
2961		3132
2962	That means that if you want to queue data, you have to provide your own	3133	That means that if you want to queue data, you have to provide your own
2963	queue. But at least I can tell you how to implement locking around your	3134	queue. But at least I can tell you how to implement locking around your
2964	queue:	3135	queue:
2965		3136
…		…
3104		3275
3105	If C<timeout> is less than 0, then no timeout watcher will be	3276	If C<timeout> is less than 0, then no timeout watcher will be
3106	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3277	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
3107	repeat = 0) will be started. C<0> is a valid timeout.	3278	repeat = 0) will be started. C<0> is a valid timeout.
3108		3279
3109	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	3280	The callback has the type C<void (*cb)(int revents, void *arg)> and is
3110	passed an C<revents> set like normal event callbacks (a combination of	3281	passed an C<revents> set like normal event callbacks (a combination of
3111	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3282	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
3112	value passed to C<ev_once>. Note that it is possible to receive I<both>	3283	value passed to C<ev_once>. Note that it is possible to receive I<both>
3113	a timeout and an io event at the same time - you probably should give io	3284	a timeout and an io event at the same time - you probably should give io
3114	events precedence.	3285	events precedence.
3115		3286
3116	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3287	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
3117		3288
3118	static void stdin_ready (int revents, void *arg)	3289	static void stdin_ready (int revents, void *arg)
3119	{	3290	{
3120	if (revents & EV_READ)	3291	if (revents & EV_READ)
3121	/* stdin might have data for us, joy! */;	3292	/* stdin might have data for us, joy! */;
3122	else if (revents & EV_TIMEOUT)	3293	else if (revents & EV_TIMER)
3123	/* doh, nothing entered */;	3294	/* doh, nothing entered */;
3124	}	3295	}
3125		3296
3126	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3297	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3127		3298
3128	=item ev_feed_event (struct ev_loop *, watcher *, int revents)
3129
3130	Feeds the given event set into the event loop, as if the specified event
3131	had happened for the specified watcher (which must be a pointer to an
3132	initialised but not necessarily started event watcher).
3133
3134	=item ev_feed_fd_event (struct ev_loop *, int fd, int revents)	3299	=item ev_feed_fd_event (loop, int fd, int revents)
3135		3300
3136	Feed an event on the given fd, as if a file descriptor backend detected	3301	Feed an event on the given fd, as if a file descriptor backend detected
3137	the given events it.	3302	the given events it.
3138		3303
3139	=item ev_feed_signal_event (struct ev_loop *loop, int signum)	3304	=item ev_feed_signal_event (loop, int signum)
3140		3305
3141	Feed an event as if the given signal occurred (C<loop> must be the default	3306	Feed an event as if the given signal occurred (C<loop> must be the default
3142	loop!).	3307	loop!).
3143		3308
3144	=back	3309	=back
…		…
3224		3389
3225	=over 4	3390	=over 4
3226		3391
3227	=item ev::TYPE::TYPE ()	3392	=item ev::TYPE::TYPE ()
3228		3393
3229	=item ev::TYPE::TYPE (struct ev_loop *)	3394	=item ev::TYPE::TYPE (loop)
3230		3395
3231	=item ev::TYPE::~TYPE	3396	=item ev::TYPE::~TYPE
3232		3397
3233	The constructor (optionally) takes an event loop to associate the watcher	3398	The constructor (optionally) takes an event loop to associate the watcher
3234	with. If it is omitted, it will use C<EV_DEFAULT>.	3399	with. If it is omitted, it will use C<EV_DEFAULT>.
…		…
3267	myclass obj;	3432	myclass obj;
3268	ev::io iow;	3433	ev::io iow;
3269	iow.set <myclass, &myclass::io_cb> (&obj);	3434	iow.set <myclass, &myclass::io_cb> (&obj);
3270		3435
3271	=item w->set (object *)	3436	=item w->set (object *)
3272
3273	This is an B<experimental> feature that might go away in a future version.
3274		3437
3275	This is a variation of a method callback - leaving out the method to call	3438	This is a variation of a method callback - leaving out the method to call
3276	will default the method to C<operator ()>, which makes it possible to use	3439	will default the method to C<operator ()>, which makes it possible to use
3277	functor objects without having to manually specify the C<operator ()> all	3440	functor objects without having to manually specify the C<operator ()> all
3278	the time. Incidentally, you can then also leave out the template argument	3441	the time. Incidentally, you can then also leave out the template argument
…		…
3311	Example: Use a plain function as callback.	3474	Example: Use a plain function as callback.
3312		3475
3313	static void io_cb (ev::io &w, int revents) { }	3476	static void io_cb (ev::io &w, int revents) { }
3314	iow.set <io_cb> ();	3477	iow.set <io_cb> ();
3315		3478
3316	=item w->set (struct ev_loop *)	3479	=item w->set (loop)
3317		3480
3318	Associates a different C<struct ev_loop> with this watcher. You can only	3481	Associates a different C<struct ev_loop> with this watcher. You can only
3319	do this when the watcher is inactive (and not pending either).	3482	do this when the watcher is inactive (and not pending either).
3320		3483
3321	=item w->set ([arguments])	3484	=item w->set ([arguments])
3322		3485
3323	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3486	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3324	called at least once. Unlike the C counterpart, an active watcher gets	3487	method or a suitable start method must be called at least once. Unlike the
3325	automatically stopped and restarted when reconfiguring it with this	3488	C counterpart, an active watcher gets automatically stopped and restarted
3326	method.	3489	when reconfiguring it with this method.
3327		3490
3328	=item w->start ()	3491	=item w->start ()
3329		3492
3330	Starts the watcher. Note that there is no C<loop> argument, as the	3493	Starts the watcher. Note that there is no C<loop> argument, as the
3331	constructor already stores the event loop.	3494	constructor already stores the event loop.
3332		3495
		3496	=item w->start ([arguments])
		3497
		3498	Instead of calling C<set> and C<start> methods separately, it is often
		3499	convenient to wrap them in one call. Uses the same type of arguments as
		3500	the configure C<set> method of the watcher.
		3501
3333	=item w->stop ()	3502	=item w->stop ()
3334		3503
3335	Stops the watcher if it is active. Again, no C<loop> argument.	3504	Stops the watcher if it is active. Again, no C<loop> argument.
3336		3505
3337	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3506	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3349		3518
3350	=back	3519	=back
3351		3520
3352	=back	3521	=back
3353		3522
3354	Example: Define a class with an IO and idle watcher, start one of them in	3523	Example: Define a class with two I/O and idle watchers, start the I/O
3355	the constructor.	3524	watchers in the constructor.
3356		3525
3357	class myclass	3526	class myclass
3358	{	3527	{
3359	ev::io io ; void io_cb (ev::io &w, int revents);	3528	ev::io io ; void io_cb (ev::io &w, int revents);
		3529	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3360	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3530	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3361		3531
3362	myclass (int fd)	3532	myclass (int fd)
3363	{	3533	{
3364	io .set <myclass, &myclass::io_cb > (this);	3534	io .set <myclass, &myclass::io_cb > (this);
		3535	io2 .set <myclass, &myclass::io2_cb > (this);
3365	idle.set <myclass, &myclass::idle_cb> (this);	3536	idle.set <myclass, &myclass::idle_cb> (this);
3366		3537
3367	io.start (fd, ev::READ);	3538	io.set (fd, ev::WRITE); // configure the watcher
		3539	io.start (); // start it whenever convenient
		3540
		3541	io2.start (fd, ev::READ); // set + start in one call
3368	}	3542	}
3369	};	3543	};
3370		3544
3371		3545
3372	=head1 OTHER LANGUAGE BINDINGS	3546	=head1 OTHER LANGUAGE BINDINGS
…		…
3420	Erkki Seppala has written Ocaml bindings for libev, to be found at	3594	Erkki Seppala has written Ocaml bindings for libev, to be found at
3421	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.	3595	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
3422		3596
3423	=item Lua	3597	=item Lua
3424		3598
3425	Brian Maher has written a partial interface to libev	3599	Brian Maher has written a partial interface to libev for lua (at the
3426	for lua (only C<ev_io> and C<ev_timer>), to be found at	3600	time of this writing, only C<ev_io> and C<ev_timer>), to be found at
3427	L<http://github.com/brimworks/lua-ev>.	3601	L<http://github.com/brimworks/lua-ev>.
3428		3602
3429	=back	3603	=back
3430		3604
3431		3605
…		…
3446	loop argument"). The C<EV_A> form is used when this is the sole argument,	3620	loop argument"). The C<EV_A> form is used when this is the sole argument,
3447	C<EV_A_> is used when other arguments are following. Example:	3621	C<EV_A_> is used when other arguments are following. Example:
3448		3622
3449	ev_unref (EV_A);	3623	ev_unref (EV_A);
3450	ev_timer_add (EV_A_ watcher);	3624	ev_timer_add (EV_A_ watcher);
3451	ev_loop (EV_A_ 0);	3625	ev_run (EV_A_ 0);
3452		3626
3453	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3627	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3454	which is often provided by the following macro.	3628	which is often provided by the following macro.
3455		3629
3456	=item C<EV_P>, C<EV_P_>	3630	=item C<EV_P>, C<EV_P_>
…		…
3496	}	3670	}
3497		3671
3498	ev_check check;	3672	ev_check check;
3499	ev_check_init (&check, check_cb);	3673	ev_check_init (&check, check_cb);
3500	ev_check_start (EV_DEFAULT_ &check);	3674	ev_check_start (EV_DEFAULT_ &check);
3501	ev_loop (EV_DEFAULT_ 0);	3675	ev_run (EV_DEFAULT_ 0);
3502		3676
3503	=head1 EMBEDDING	3677	=head1 EMBEDDING
3504		3678
3505	Libev can (and often is) directly embedded into host	3679	Libev can (and often is) directly embedded into host
3506	applications. Examples of applications that embed it include the Deliantra	3680	applications. Examples of applications that embed it include the Deliantra
…		…
3586	libev.m4	3760	libev.m4
3587		3761
3588	=head2 PREPROCESSOR SYMBOLS/MACROS	3762	=head2 PREPROCESSOR SYMBOLS/MACROS
3589		3763
3590	Libev can be configured via a variety of preprocessor symbols you have to	3764	Libev can be configured via a variety of preprocessor symbols you have to
3591	define before including any of its files. The default in the absence of	3765	define before including (or compiling) any of its files. The default in
3592	autoconf is documented for every option.	3766	the absence of autoconf is documented for every option.
		3767
		3768	Symbols marked with "(h)" do not change the ABI, and can have different
		3769	values when compiling libev vs. including F<ev.h>, so it is permissible
		3770	to redefine them before including F<ev.h> without breaking compatibility
		3771	to a compiled library. All other symbols change the ABI, which means all
		3772	users of libev and the libev code itself must be compiled with compatible
		3773	settings.
3593		3774
3594	=over 4	3775	=over 4
3595		3776
		3777	=item EV_COMPAT3 (h)
		3778
		3779	Backwards compatibility is a major concern for libev. This is why this
		3780	release of libev comes with wrappers for the functions and symbols that
		3781	have been renamed between libev version 3 and 4.
		3782
		3783	You can disable these wrappers (to test compatibility with future
		3784	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3785	sources. This has the additional advantage that you can drop the C<struct>
		3786	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3787	typedef in that case.
		3788
		3789	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3790	and in some even more future version the compatibility code will be
		3791	removed completely.
		3792
3596	=item EV_STANDALONE	3793	=item EV_STANDALONE (h)
3597		3794
3598	Must always be C<1> if you do not use autoconf configuration, which	3795	Must always be C<1> if you do not use autoconf configuration, which
3599	keeps libev from including F<config.h>, and it also defines dummy	3796	keeps libev from including F<config.h>, and it also defines dummy
3600	implementations for some libevent functions (such as logging, which is not	3797	implementations for some libevent functions (such as logging, which is not
3601	supported). It will also not define any of the structs usually found in	3798	supported). It will also not define any of the structs usually found in
…		…
3751	as well as for signal and thread safety in C<ev_async> watchers.	3948	as well as for signal and thread safety in C<ev_async> watchers.
3752		3949
3753	In the absence of this define, libev will use C<sig_atomic_t volatile>	3950	In the absence of this define, libev will use C<sig_atomic_t volatile>
3754	(from F<signal.h>), which is usually good enough on most platforms.	3951	(from F<signal.h>), which is usually good enough on most platforms.
3755		3952
3756	=item EV_H	3953	=item EV_H (h)
3757		3954
3758	The name of the F<ev.h> header file used to include it. The default if	3955	The name of the F<ev.h> header file used to include it. The default if
3759	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be	3956	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
3760	used to virtually rename the F<ev.h> header file in case of conflicts.	3957	used to virtually rename the F<ev.h> header file in case of conflicts.
3761		3958
3762	=item EV_CONFIG_H	3959	=item EV_CONFIG_H (h)
3763		3960
3764	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	3961	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
3765	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	3962	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
3766	C<EV_H>, above.	3963	C<EV_H>, above.
3767		3964
3768	=item EV_EVENT_H	3965	=item EV_EVENT_H (h)
3769		3966
3770	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	3967	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
3771	of how the F<event.h> header can be found, the default is C<"event.h">.	3968	of how the F<event.h> header can be found, the default is C<"event.h">.
3772		3969
3773	=item EV_PROTOTYPES	3970	=item EV_PROTOTYPES (h)
3774		3971
3775	If defined to be C<0>, then F<ev.h> will not define any function	3972	If defined to be C<0>, then F<ev.h> will not define any function
3776	prototypes, but still define all the structs and other symbols. This is	3973	prototypes, but still define all the structs and other symbols. This is
3777	occasionally useful if you want to provide your own wrapper functions	3974	occasionally useful if you want to provide your own wrapper functions
3778	around libev functions.	3975	around libev functions.
…		…
3800	fine.	3997	fine.
3801		3998
3802	If your embedding application does not need any priorities, defining these	3999	If your embedding application does not need any priorities, defining these
3803	both to C<0> will save some memory and CPU.	4000	both to C<0> will save some memory and CPU.
3804		4001
3805	=item EV_PERIODIC_ENABLE	4002	=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
		4003	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
		4004	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3806		4005
3807	If undefined or defined to be C<1>, then periodic timers are supported. If	4006	If undefined or defined to be C<1> (and the platform supports it), then
3808	defined to be C<0>, then they are not. Disabling them saves a few kB of	4007	the respective watcher type is supported. If defined to be C<0>, then it
3809	code.	4008	is not. Disabling watcher types mainly saves code size.
3810		4009
3811	=item EV_IDLE_ENABLE	4010	=item EV_FEATURES
3812
3813	If undefined or defined to be C<1>, then idle watchers are supported. If
3814	defined to be C<0>, then they are not. Disabling them saves a few kB of
3815	code.
3816
3817	=item EV_EMBED_ENABLE
3818
3819	If undefined or defined to be C<1>, then embed watchers are supported. If
3820	defined to be C<0>, then they are not. Embed watchers rely on most other
3821	watcher types, which therefore must not be disabled.
3822
3823	=item EV_STAT_ENABLE
3824
3825	If undefined or defined to be C<1>, then stat watchers are supported. If
3826	defined to be C<0>, then they are not.
3827
3828	=item EV_FORK_ENABLE
3829
3830	If undefined or defined to be C<1>, then fork watchers are supported. If
3831	defined to be C<0>, then they are not.
3832
3833	=item EV_ASYNC_ENABLE
3834
3835	If undefined or defined to be C<1>, then async watchers are supported. If
3836	defined to be C<0>, then they are not.
3837
3838	=item EV_MINIMAL
3839		4011
3840	If you need to shave off some kilobytes of code at the expense of some	4012	If you need to shave off some kilobytes of code at the expense of some
3841	speed (but with the full API), define this symbol to C<1>. Currently this	4013	speed (but with the full API), you can define this symbol to request
3842	is used to override some inlining decisions, saves roughly 30% code size	4014	certain subsets of functionality. The default is to enable all features
3843	on amd64. It also selects a much smaller 2-heap for timer management over	4015	that can be enabled on the platform.
3844	the default 4-heap.
3845		4016
3846	You can save even more by disabling watcher types you do not need	4017	A typical way to use this symbol is to define it to C<0> (or to a bitset
3847	and setting C<EV_MAXPRI> == C<EV_MINPRI>. Also, disabling C<assert>	4018	with some broad features you want) and then selectively re-enable
3848	(C<-DNDEBUG>) will usually reduce code size a lot.	4019	additional parts you want, for example if you want everything minimal,
		4020	but multiple event loop support, async and child watchers and the poll
		4021	backend, use this:
3849		4022
3850	Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to	4023	#define EV_FEATURES 0
3851	provide a bare-bones event library. See C<ev.h> for details on what parts	4024	#define EV_MULTIPLICITY 1
3852	of the API are still available, and do not complain if this subset changes	4025	#define EV_USE_POLL 1
3853	over time.	4026	#define EV_CHILD_ENABLE 1
		4027	#define EV_ASYNC_ENABLE 1
		4028
		4029	The actual value is a bitset, it can be a combination of the following
		4030	values:
		4031
		4032	=over 4
		4033
		4034	=item C<1> - faster/larger code
		4035
		4036	Use larger code to speed up some operations.
		4037
		4038	Currently this is used to override some inlining decisions (enlarging the
		4039	code size by roughly 30% on amd64).
		4040
		4041	When optimising for size, use of compiler flags such as C<-Os> with
		4042	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
		4043	assertions.
		4044
		4045	=item C<2> - faster/larger data structures
		4046
		4047	Replaces the small 2-heap for timer management by a faster 4-heap, larger
		4048	hash table sizes and so on. This will usually further increase code size
		4049	and can additionally have an effect on the size of data structures at
		4050	runtime.
		4051
		4052	=item C<4> - full API configuration
		4053
		4054	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
		4055	enables multiplicity (C<EV_MULTIPLICITY>=1).
		4056
		4057	=item C<8> - full API
		4058
		4059	This enables a lot of the "lesser used" API functions. See C<ev.h> for
		4060	details on which parts of the API are still available without this
		4061	feature, and do not complain if this subset changes over time.
		4062
		4063	=item C<16> - enable all optional watcher types
		4064
		4065	Enables all optional watcher types. If you want to selectively enable
		4066	only some watcher types other than I/O and timers (e.g. prepare,
		4067	embed, async, child...) you can enable them manually by defining
		4068	C<EV_watchertype_ENABLE> to C<1> instead.
		4069
		4070	=item C<32> - enable all backends
		4071
		4072	This enables all backends - without this feature, you need to enable at
		4073	least one backend manually (C<EV_USE_SELECT> is a good choice).
		4074
		4075	=item C<64> - enable OS-specific "helper" APIs
		4076
		4077	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
		4078	default.
		4079
		4080	=back
		4081
		4082	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
		4083	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
		4084	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
		4085	watchers, timers and monotonic clock support.
		4086
		4087	With an intelligent-enough linker (gcc+binutils are intelligent enough
		4088	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
		4089	your program might be left out as well - a binary starting a timer and an
		4090	I/O watcher then might come out at only 5Kb.
		4091
		4092	=item EV_AVOID_STDIO
		4093
		4094	If this is set to C<1> at compiletime, then libev will avoid using stdio
		4095	functions (printf, scanf, perror etc.). This will increase the code size
		4096	somewhat, but if your program doesn't otherwise depend on stdio and your
		4097	libc allows it, this avoids linking in the stdio library which is quite
		4098	big.
		4099
		4100	Note that error messages might become less precise when this option is
		4101	enabled.
3854		4102
3855	=item EV_NSIG	4103	=item EV_NSIG
3856		4104
3857	The highest supported signal number, +1 (or, the number of	4105	The highest supported signal number, +1 (or, the number of
3858	signals): Normally, libev tries to deduce the maximum number of signals	4106	signals): Normally, libev tries to deduce the maximum number of signals
3859	automatically, but sometimes this fails, in which case it can be	4107	automatically, but sometimes this fails, in which case it can be
3860	specified. Also, using a lower number than detected (C<32> should be	4108	specified. Also, using a lower number than detected (C<32> should be
3861	good for about any system in existance) can save some memory, as libev	4109	good for about any system in existence) can save some memory, as libev
3862	statically allocates some 12-24 bytes per signal number.	4110	statically allocates some 12-24 bytes per signal number.
3863		4111
3864	=item EV_PID_HASHSIZE	4112	=item EV_PID_HASHSIZE
3865		4113
3866	C<ev_child> watchers use a small hash table to distribute workload by	4114	C<ev_child> watchers use a small hash table to distribute workload by
3867	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	4115	pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
3868	than enough. If you need to manage thousands of children you might want to	4116	usually more than enough. If you need to manage thousands of children you
3869	increase this value (I<must> be a power of two).	4117	might want to increase this value (I<must> be a power of two).
3870		4118
3871	=item EV_INOTIFY_HASHSIZE	4119	=item EV_INOTIFY_HASHSIZE
3872		4120
3873	C<ev_stat> watchers use a small hash table to distribute workload by	4121	C<ev_stat> watchers use a small hash table to distribute workload by
3874	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	4122	inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
3875	usually more than enough. If you need to manage thousands of C<ev_stat>	4123	disabled), usually more than enough. If you need to manage thousands of
3876	watchers you might want to increase this value (I<must> be a power of	4124	C<ev_stat> watchers you might want to increase this value (I<must> be a
3877	two).	4125	power of two).
3878		4126
3879	=item EV_USE_4HEAP	4127	=item EV_USE_4HEAP
3880		4128
3881	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4129	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3882	timer and periodics heaps, libev uses a 4-heap when this symbol is defined	4130	timer and periodics heaps, libev uses a 4-heap when this symbol is defined
3883	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably	4131	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
3884	faster performance with many (thousands) of watchers.	4132	faster performance with many (thousands) of watchers.
3885		4133
3886	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4134	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3887	(disabled).	4135	will be C<0>.
3888		4136
3889	=item EV_HEAP_CACHE_AT	4137	=item EV_HEAP_CACHE_AT
3890		4138
3891	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4139	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3892	timer and periodics heaps, libev can cache the timestamp (I<at>) within	4140	timer and periodics heaps, libev can cache the timestamp (I<at>) within
3893	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	4141	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3894	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	4142	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3895	but avoids random read accesses on heap changes. This improves performance	4143	but avoids random read accesses on heap changes. This improves performance
3896	noticeably with many (hundreds) of watchers.	4144	noticeably with many (hundreds) of watchers.
3897		4145
3898	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4146	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3899	(disabled).	4147	will be C<0>.
3900		4148
3901	=item EV_VERIFY	4149	=item EV_VERIFY
3902		4150
3903	Controls how much internal verification (see C<ev_loop_verify ()>) will	4151	Controls how much internal verification (see C<ev_verify ()>) will
3904	be done: If set to C<0>, no internal verification code will be compiled	4152	be done: If set to C<0>, no internal verification code will be compiled
3905	in. If set to C<1>, then verification code will be compiled in, but not	4153	in. If set to C<1>, then verification code will be compiled in, but not
3906	called. If set to C<2>, then the internal verification code will be	4154	called. If set to C<2>, then the internal verification code will be
3907	called once per loop, which can slow down libev. If set to C<3>, then the	4155	called once per loop, which can slow down libev. If set to C<3>, then the
3908	verification code will be called very frequently, which will slow down	4156	verification code will be called very frequently, which will slow down
3909	libev considerably.	4157	libev considerably.
3910		4158
3911	The default is C<1>, unless C<EV_MINIMAL> is set, in which case it will be	4159	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3912	C<0>.	4160	will be C<0>.
3913		4161
3914	=item EV_COMMON	4162	=item EV_COMMON
3915		4163
3916	By default, all watchers have a C<void *data> member. By redefining	4164	By default, all watchers have a C<void *data> member. By redefining
3917	this macro to a something else you can include more and other types of	4165	this macro to something else you can include more and other types of
3918	members. You have to define it each time you include one of the files,	4166	members. You have to define it each time you include one of the files,
3919	though, and it must be identical each time.	4167	though, and it must be identical each time.
3920		4168
3921	For example, the perl EV module uses something like this:	4169	For example, the perl EV module uses something like this:
3922		4170
…		…
3975	file.	4223	file.
3976		4224
3977	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4225	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
3978	that everybody includes and which overrides some configure choices:	4226	that everybody includes and which overrides some configure choices:
3979		4227
3980	#define EV_MINIMAL 1	4228	#define EV_FEATURES 8
3981	#define EV_USE_POLL 0	4229	#define EV_USE_SELECT 1
3982	#define EV_MULTIPLICITY 0
3983	#define EV_PERIODIC_ENABLE 0	4230	#define EV_PREPARE_ENABLE 1
		4231	#define EV_IDLE_ENABLE 1
3984	#define EV_STAT_ENABLE 0	4232	#define EV_SIGNAL_ENABLE 1
3985	#define EV_FORK_ENABLE 0	4233	#define EV_CHILD_ENABLE 1
		4234	#define EV_USE_STDEXCEPT 0
3986	#define EV_CONFIG_H <config.h>	4235	#define EV_CONFIG_H <config.h>
3987	#define EV_MINPRI 0
3988	#define EV_MAXPRI 0
3989		4236
3990	#include "ev++.h"	4237	#include "ev++.h"
3991		4238
3992	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4239	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3993		4240
…		…
4124	userdata *u = ev_userdata (EV_A);	4371	userdata *u = ev_userdata (EV_A);
4125	pthread_mutex_lock (&u->lock);	4372	pthread_mutex_lock (&u->lock);
4126	}	4373	}
4127		4374
4128	The event loop thread first acquires the mutex, and then jumps straight	4375	The event loop thread first acquires the mutex, and then jumps straight
4129	into C<ev_loop>:	4376	into C<ev_run>:
4130		4377
4131	void *	4378	void *
4132	l_run (void *thr_arg)	4379	l_run (void *thr_arg)
4133	{	4380	{
4134	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4381	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4135		4382
4136	l_acquire (EV_A);	4383	l_acquire (EV_A);
4137	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4384	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4138	ev_loop (EV_A_ 0);	4385	ev_run (EV_A_ 0);
4139	l_release (EV_A);	4386	l_release (EV_A);
4140		4387
4141	return 0;	4388	return 0;
4142	}	4389	}
4143		4390
…		…
4195		4442
4196	=head3 COROUTINES	4443	=head3 COROUTINES
4197		4444
4198	Libev is very accommodating to coroutines ("cooperative threads"):	4445	Libev is very accommodating to coroutines ("cooperative threads"):
4199	libev fully supports nesting calls to its functions from different	4446	libev fully supports nesting calls to its functions from different
4200	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4447	coroutines (e.g. you can call C<ev_run> on the same loop from two
4201	different coroutines, and switch freely between both coroutines running	4448	different coroutines, and switch freely between both coroutines running
4202	the loop, as long as you don't confuse yourself). The only exception is	4449	the loop, as long as you don't confuse yourself). The only exception is
4203	that you must not do this from C<ev_periodic> reschedule callbacks.	4450	that you must not do this from C<ev_periodic> reschedule callbacks.
4204		4451
4205	Care has been taken to ensure that libev does not keep local state inside	4452	Care has been taken to ensure that libev does not keep local state inside
4206	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4453	C<ev_run>, and other calls do not usually allow for coroutine switches as
4207	they do not call any callbacks.	4454	they do not call any callbacks.
4208		4455
4209	=head2 COMPILER WARNINGS	4456	=head2 COMPILER WARNINGS
4210		4457
4211	Depending on your compiler and compiler settings, you might get no or a	4458	Depending on your compiler and compiler settings, you might get no or a
…		…
4222	maintainable.	4469	maintainable.
4223		4470
4224	And of course, some compiler warnings are just plain stupid, or simply	4471	And of course, some compiler warnings are just plain stupid, or simply
4225	wrong (because they don't actually warn about the condition their message	4472	wrong (because they don't actually warn about the condition their message
4226	seems to warn about). For example, certain older gcc versions had some	4473	seems to warn about). For example, certain older gcc versions had some
4227	warnings that resulted an extreme number of false positives. These have	4474	warnings that resulted in an extreme number of false positives. These have
4228	been fixed, but some people still insist on making code warn-free with	4475	been fixed, but some people still insist on making code warn-free with
4229	such buggy versions.	4476	such buggy versions.
4230		4477
4231	While libev is written to generate as few warnings as possible,	4478	While libev is written to generate as few warnings as possible,
4232	"warn-free" code is not a goal, and it is recommended not to build libev	4479	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4268	I suggest using suppression lists.	4515	I suggest using suppression lists.
4269		4516
4270		4517
4271	=head1 PORTABILITY NOTES	4518	=head1 PORTABILITY NOTES
4272		4519
		4520	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4521
		4522	GNU/Linux is the only common platform that supports 64 bit file/large file
		4523	interfaces but I<disables> them by default.
		4524
		4525	That means that libev compiled in the default environment doesn't support
		4526	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4527
		4528	Unfortunately, many programs try to work around this GNU/Linux issue
		4529	by enabling the large file API, which makes them incompatible with the
		4530	standard libev compiled for their system.
		4531
		4532	Likewise, libev cannot enable the large file API itself as this would
		4533	suddenly make it incompatible to the default compile time environment,
		4534	i.e. all programs not using special compile switches.
		4535
		4536	=head2 OS/X AND DARWIN BUGS
		4537
		4538	The whole thing is a bug if you ask me - basically any system interface
		4539	you touch is broken, whether it is locales, poll, kqueue or even the
		4540	OpenGL drivers.
		4541
		4542	=head3 C<kqueue> is buggy
		4543
		4544	The kqueue syscall is broken in all known versions - most versions support
		4545	only sockets, many support pipes.
		4546
		4547	Libev tries to work around this by not using C<kqueue> by default on this
		4548	rotten platform, but of course you can still ask for it when creating a
		4549	loop - embedding a socket-only kqueue loop into a select-based one is
		4550	probably going to work well.
		4551
		4552	=head3 C<poll> is buggy
		4553
		4554	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4555	implementation by something calling C<kqueue> internally around the 10.5.6
		4556	release, so now C<kqueue> I<and> C<poll> are broken.
		4557
		4558	Libev tries to work around this by not using C<poll> by default on
		4559	this rotten platform, but of course you can still ask for it when creating
		4560	a loop.
		4561
		4562	=head3 C<select> is buggy
		4563
		4564	All that's left is C<select>, and of course Apple found a way to fuck this
		4565	one up as well: On OS/X, C<select> actively limits the number of file
		4566	descriptors you can pass in to 1024 - your program suddenly crashes when
		4567	you use more.
		4568
		4569	There is an undocumented "workaround" for this - defining
		4570	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4571	work on OS/X.
		4572
		4573	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4574
		4575	=head3 C<errno> reentrancy
		4576
		4577	The default compile environment on Solaris is unfortunately so
		4578	thread-unsafe that you can't even use components/libraries compiled
		4579	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4580	defined by default. A valid, if stupid, implementation choice.
		4581
		4582	If you want to use libev in threaded environments you have to make sure
		4583	it's compiled with C<_REENTRANT> defined.
		4584
		4585	=head3 Event port backend
		4586
		4587	The scalable event interface for Solaris is called "event
		4588	ports". Unfortunately, this mechanism is very buggy in all major
		4589	releases. If you run into high CPU usage, your program freezes or you get
		4590	a large number of spurious wakeups, make sure you have all the relevant
		4591	and latest kernel patches applied. No, I don't know which ones, but there
		4592	are multiple ones to apply, and afterwards, event ports actually work
		4593	great.
		4594
		4595	If you can't get it to work, you can try running the program by setting
		4596	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4597	C<select> backends.
		4598
		4599	=head2 AIX POLL BUG
		4600
		4601	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4602	this by trying to avoid the poll backend altogether (i.e. it's not even
		4603	compiled in), which normally isn't a big problem as C<select> works fine
		4604	with large bitsets on AIX, and AIX is dead anyway.
		4605
4273	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4606	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4607
		4608	=head3 General issues
4274		4609
4275	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4610	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4276	requires, and its I/O model is fundamentally incompatible with the POSIX	4611	requires, and its I/O model is fundamentally incompatible with the POSIX
4277	model. Libev still offers limited functionality on this platform in	4612	model. Libev still offers limited functionality on this platform in
4278	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4613	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4279	descriptors. This only applies when using Win32 natively, not when using	4614	descriptors. This only applies when using Win32 natively, not when using
4280	e.g. cygwin.	4615	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4616	as every compielr comes with a slightly differently broken/incompatible
		4617	environment.
4281		4618
4282	Lifting these limitations would basically require the full	4619	Lifting these limitations would basically require the full
4283	re-implementation of the I/O system. If you are into these kinds of	4620	re-implementation of the I/O system. If you are into this kind of thing,
4284	things, then note that glib does exactly that for you in a very portable	4621	then note that glib does exactly that for you in a very portable way (note
4285	way (note also that glib is the slowest event library known to man).	4622	also that glib is the slowest event library known to man).
4286		4623
4287	There is no supported compilation method available on windows except	4624	There is no supported compilation method available on windows except
4288	embedding it into other applications.	4625	embedding it into other applications.
4289		4626
4290	Sensible signal handling is officially unsupported by Microsoft - libev	4627	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4318	you do I<not> compile the F<ev.c> or any other embedded source files!):	4655	you do I<not> compile the F<ev.c> or any other embedded source files!):
4319		4656
4320	#include "evwrap.h"	4657	#include "evwrap.h"
4321	#include "ev.c"	4658	#include "ev.c"
4322		4659
4323	=over 4
4324
4325	=item The winsocket select function	4660	=head3 The winsocket C<select> function
4326		4661
4327	The winsocket C<select> function doesn't follow POSIX in that it	4662	The winsocket C<select> function doesn't follow POSIX in that it
4328	requires socket I<handles> and not socket I<file descriptors> (it is	4663	requires socket I<handles> and not socket I<file descriptors> (it is
4329	also extremely buggy). This makes select very inefficient, and also	4664	also extremely buggy). This makes select very inefficient, and also
4330	requires a mapping from file descriptors to socket handles (the Microsoft	4665	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4339	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4674	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4340		4675
4341	Note that winsockets handling of fd sets is O(n), so you can easily get a	4676	Note that winsockets handling of fd sets is O(n), so you can easily get a
4342	complexity in the O(n²) range when using win32.	4677	complexity in the O(n²) range when using win32.
4343		4678
4344	=item Limited number of file descriptors	4679	=head3 Limited number of file descriptors
4345		4680
4346	Windows has numerous arbitrary (and low) limits on things.	4681	Windows has numerous arbitrary (and low) limits on things.
4347		4682
4348	Early versions of winsocket's select only supported waiting for a maximum	4683	Early versions of winsocket's select only supported waiting for a maximum
4349	of C<64> handles (probably owning to the fact that all windows kernels	4684	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4364	runtime libraries. This might get you to about C<512> or C<2048> sockets	4699	runtime libraries. This might get you to about C<512> or C<2048> sockets
4365	(depending on windows version and/or the phase of the moon). To get more,	4700	(depending on windows version and/or the phase of the moon). To get more,
4366	you need to wrap all I/O functions and provide your own fd management, but	4701	you need to wrap all I/O functions and provide your own fd management, but
4367	the cost of calling select (O(n²)) will likely make this unworkable.	4702	the cost of calling select (O(n²)) will likely make this unworkable.
4368		4703
4369	=back
4370
4371	=head2 PORTABILITY REQUIREMENTS	4704	=head2 PORTABILITY REQUIREMENTS
4372		4705
4373	In addition to a working ISO-C implementation and of course the	4706	In addition to a working ISO-C implementation and of course the
4374	backend-specific APIs, libev relies on a few additional extensions:	4707	backend-specific APIs, libev relies on a few additional extensions:
4375		4708
…		…
4413	watchers.	4746	watchers.
4414		4747
4415	=item C<double> must hold a time value in seconds with enough accuracy	4748	=item C<double> must hold a time value in seconds with enough accuracy
4416		4749
4417	The type C<double> is used to represent timestamps. It is required to	4750	The type C<double> is used to represent timestamps. It is required to
4418	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4751	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4419	enough for at least into the year 4000. This requirement is fulfilled by	4752	good enough for at least into the year 4000 with millisecond accuracy
		4753	(the design goal for libev). This requirement is overfulfilled by
4420	implementations implementing IEEE 754, which is basically all existing	4754	implementations using IEEE 754, which is basically all existing ones. With
4421	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4755	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4422	2200.
4423		4756
4424	=back	4757	=back
4425		4758
4426	If you know of other additional requirements drop me a note.	4759	If you know of other additional requirements drop me a note.
4427		4760
…		…
4495	involves iterating over all running async watchers or all signal numbers.	4828	involves iterating over all running async watchers or all signal numbers.
4496		4829
4497	=back	4830	=back
4498		4831
4499		4832
		4833	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4834
		4835	The major version 4 introduced some minor incompatible changes to the API.
		4836
		4837	At the moment, the C<ev.h> header file tries to implement superficial
		4838	compatibility, so most programs should still compile. Those might be
		4839	removed in later versions of libev, so better update early than late.
		4840
		4841	=over 4
		4842
		4843	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4844
		4845	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4846
		4847	ev_loop_destroy (EV_DEFAULT);
		4848	ev_loop_fork (EV_DEFAULT);
		4849
		4850	=item function/symbol renames
		4851
		4852	A number of functions and symbols have been renamed:
		4853
		4854	ev_loop => ev_run
		4855	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4856	EVLOOP_ONESHOT => EVRUN_ONCE
		4857
		4858	ev_unloop => ev_break
		4859	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4860	EVUNLOOP_ONE => EVBREAK_ONE
		4861	EVUNLOOP_ALL => EVBREAK_ALL
		4862
		4863	EV_TIMEOUT => EV_TIMER
		4864
		4865	ev_loop_count => ev_iteration
		4866	ev_loop_depth => ev_depth
		4867	ev_loop_verify => ev_verify
		4868
		4869	Most functions working on C<struct ev_loop> objects don't have an
		4870	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4871	associated constants have been renamed to not collide with the C<struct
		4872	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4873	as all other watcher types. Note that C<ev_loop_fork> is still called
		4874	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4875	typedef.
		4876
		4877	=item C<EV_COMPAT3> backwards compatibility mechanism
		4878
		4879	The backward compatibility mechanism can be controlled by
		4880	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4881	section.
		4882
		4883	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4884
		4885	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4886	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4887	and work, but the library code will of course be larger.
		4888
		4889	=back
		4890
		4891
4500	=head1 GLOSSARY	4892	=head1 GLOSSARY
4501		4893
4502	=over 4	4894	=over 4
4503		4895
4504	=item active	4896	=item active
4505		4897
4506	A watcher is active as long as it has been started (has been attached to	4898	A watcher is active as long as it has been started and not yet stopped.
4507	an event loop) but not yet stopped (disassociated from the event loop).	4899	See L<WATCHER STATES> for details.
4508		4900
4509	=item application	4901	=item application
4510		4902
4511	In this document, an application is whatever is using libev.	4903	In this document, an application is whatever is using libev.
		4904
		4905	=item backend
		4906
		4907	The part of the code dealing with the operating system interfaces.
4512		4908
4513	=item callback	4909	=item callback
4514		4910
4515	The address of a function that is called when some event has been	4911	The address of a function that is called when some event has been
4516	detected. Callbacks are being passed the event loop, the watcher that	4912	detected. Callbacks are being passed the event loop, the watcher that
4517	received the event, and the actual event bitset.	4913	received the event, and the actual event bitset.
4518		4914
4519	=item callback invocation	4915	=item callback/watcher invocation
4520		4916
4521	The act of calling the callback associated with a watcher.	4917	The act of calling the callback associated with a watcher.
4522		4918
4523	=item event	4919	=item event
4524		4920
4525	A change of state of some external event, such as data now being available	4921	A change of state of some external event, such as data now being available
4526	for reading on a file descriptor, time having passed or simply not having	4922	for reading on a file descriptor, time having passed or simply not having
4527	any other events happening anymore.	4923	any other events happening anymore.
4528		4924
4529	In libev, events are represented as single bits (such as C<EV_READ> or	4925	In libev, events are represented as single bits (such as C<EV_READ> or
4530	C<EV_TIMEOUT>).	4926	C<EV_TIMER>).
4531		4927
4532	=item event library	4928	=item event library
4533		4929
4534	A software package implementing an event model and loop.	4930	A software package implementing an event model and loop.
4535		4931
…		…
4543	The model used to describe how an event loop handles and processes	4939	The model used to describe how an event loop handles and processes
4544	watchers and events.	4940	watchers and events.
4545		4941
4546	=item pending	4942	=item pending
4547		4943
4548	A watcher is pending as soon as the corresponding event has been detected,	4944	A watcher is pending as soon as the corresponding event has been
4549	and stops being pending as soon as the watcher will be invoked or its	4945	detected. See L<WATCHER STATES> for details.
4550	pending status is explicitly cleared by the application.
4551
4552	A watcher can be pending, but not active. Stopping a watcher also clears
4553	its pending status.
4554		4946
4555	=item real time	4947	=item real time
4556		4948
4557	The physical time that is observed. It is apparently strictly monotonic :)	4949	The physical time that is observed. It is apparently strictly monotonic :)
4558		4950
…		…
4565	=item watcher	4957	=item watcher
4566		4958
4567	A data structure that describes interest in certain events. Watchers need	4959	A data structure that describes interest in certain events. Watchers need
4568	to be started (attached to an event loop) before they can receive events.	4960	to be started (attached to an event loop) before they can receive events.
4569		4961
4570	=item watcher invocation
4571
4572	The act of calling the callback associated with a watcher.
4573
4574	=back	4962	=back
4575		4963
4576	=head1 AUTHOR	4964	=head1 AUTHOR
4577		4965
4578	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4966	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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