[ViewVC] Diff of: cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.260 by root, Sun Jul 19 21:18:03 2009 UTC vs.
Revision 1.335 by root, Mon Oct 25 10:32:05 2010 UTC

…		…
26	puts ("stdin ready");	26	puts ("stdin ready");
27	// for one-shot events, one must manually stop the watcher	27	// for one-shot events, one must manually stop the watcher
28	// with its corresponding stop function.	28	// with its corresponding stop function.
29	ev_io_stop (EV_A_ w);	29	ev_io_stop (EV_A_ w);
30		30
31	// this causes all nested ev_loop's to stop iterating	31	// this causes all nested ev_run's to stop iterating
32	ev_unloop (EV_A_ EVUNLOOP_ALL);	32	ev_break (EV_A_ EVBREAK_ALL);
33	}	33	}
34		34
35	// another callback, this time for a time-out	35	// another callback, this time for a time-out
36	static void	36	static void
37	timeout_cb (EV_P_ ev_timer *w, int revents)	37	timeout_cb (EV_P_ ev_timer *w, int revents)
38	{	38	{
39	puts ("timeout");	39	puts ("timeout");
40	// this causes the innermost ev_loop to stop iterating	40	// this causes the innermost ev_run to stop iterating
41	ev_unloop (EV_A_ EVUNLOOP_ONE);	41	ev_break (EV_A_ EVBREAK_ONE);
42	}	42	}
43		43
44	int	44	int
45	main (void)	45	main (void)
46	{	46	{
47	// use the default event loop unless you have special needs	47	// use the default event loop unless you have special needs
48	struct ev_loop *loop = ev_default_loop (0);	48	struct ev_loop *loop = EV_DEFAULT;
49		49
50	// initialise an io watcher, then start it	50	// initialise an io watcher, then start it
51	// this one will watch for stdin to become readable	51	// this one will watch for stdin to become readable
52	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);	52	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
53	ev_io_start (loop, &stdin_watcher);	53	ev_io_start (loop, &stdin_watcher);
…		…
56	// simple non-repeating 5.5 second timeout	56	// simple non-repeating 5.5 second timeout
57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
58	ev_timer_start (loop, &timeout_watcher);	58	ev_timer_start (loop, &timeout_watcher);
59		59
60	// now wait for events to arrive	60	// now wait for events to arrive
61	ev_loop (loop, 0);	61	ev_run (loop, 0);
62		62
63	// unloop was called, so exit	63	// unloop was called, so exit
64	return 0;	64	return 0;
65	}	65	}
66		66
…		…
75	While this document tries to be as complete as possible in documenting	75	While this document tries to be as complete as possible in documenting
76	libev, its usage and the rationale behind its design, it is not a tutorial	76	libev, its usage and the rationale behind its design, it is not a tutorial
77	on event-based programming, nor will it introduce event-based programming	77	on event-based programming, nor will it introduce event-based programming
78	with libev.	78	with libev.
79		79
80	Familarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
		82
		83	=head1 WHAT TO READ WHEN IN A HURRY
		84
		85	This manual tries to be very detailed, but unfortunately, this also makes
		86	it very long. If you just want to know the basics of libev, I suggest
		87	reading L<ANATOMY OF A WATCHER>, then the L<EXAMPLE PROGRAM> above and
		88	look up the missing functions in L<GLOBAL FUNCTIONS> and the C<ev_io> and
		89	C<ev_timer> sections in L<WATCHER TYPES>.
82		90
83	=head1 ABOUT LIBEV	91	=head1 ABOUT LIBEV
84		92
85	Libev is an event loop: you register interest in certain events (such as a	93	Libev is an event loop: you register interest in certain events (such as a
86	file descriptor being readable or a timeout occurring), and it will manage	94	file descriptor being readable or a timeout occurring), and it will manage
…		…
98	=head2 FEATURES	106	=head2 FEATURES
99		107
100	Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the	108	Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the
101	BSD-specific C<kqueue> and the Solaris-specific event port mechanisms	109	BSD-specific C<kqueue> and the Solaris-specific event port mechanisms
102	for file descriptor events (C<ev_io>), the Linux C<inotify> interface	110	for file descriptor events (C<ev_io>), the Linux C<inotify> interface
103	(for C<ev_stat>), relative timers (C<ev_timer>), absolute timers	111	(for C<ev_stat>), Linux eventfd/signalfd (for faster and cleaner
104	with customised rescheduling (C<ev_periodic>), synchronous signals	112	inter-thread wakeup (C<ev_async>)/signal handling (C<ev_signal>)) relative
105	(C<ev_signal>), process status change events (C<ev_child>), and event	113	timers (C<ev_timer>), absolute timers with customised rescheduling
106	watchers dealing with the event loop mechanism itself (C<ev_idle>,	114	(C<ev_periodic>), synchronous signals (C<ev_signal>), process status
107	C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as	115	change events (C<ev_child>), and event watchers dealing with the event
108	file watchers (C<ev_stat>) and even limited support for fork events	116	loop mechanism itself (C<ev_idle>, C<ev_embed>, C<ev_prepare> and
109	(C<ev_fork>).	117	C<ev_check> watchers) as well as file watchers (C<ev_stat>) and even
		118	limited support for fork events (C<ev_fork>).
110		119
111	It also is quite fast (see this	120	It also is quite fast (see this
112	L<benchmark\|http://libev.schmorp.de/bench.html> comparing it to libevent	121	L<benchmark\|http://libev.schmorp.de/bench.html> comparing it to libevent
113	for example).	122	for example).
114		123
…		…
117	Libev is very configurable. In this manual the default (and most common)	126	Libev is very configurable. In this manual the default (and most common)
118	configuration will be described, which supports multiple event loops. For	127	configuration will be described, which supports multiple event loops. For
119	more info about various configuration options please have a look at	128	more info about various configuration options please have a look at
120	B<EMBED> section in this manual. If libev was configured without support	129	B<EMBED> section in this manual. If libev was configured without support
121	for multiple event loops, then all functions taking an initial argument of	130	for multiple event loops, then all functions taking an initial argument of
122	name C<loop> (which is always of type C<ev_loop *>) will not have	131	name C<loop> (which is always of type C<struct ev_loop *>) will not have
123	this argument.	132	this argument.
124		133
125	=head2 TIME REPRESENTATION	134	=head2 TIME REPRESENTATION
126		135
127	Libev represents time as a single floating point number, representing	136	Libev represents time as a single floating point number, representing
128	the (fractional) number of seconds since the (POSIX) epoch (somewhere	137	the (fractional) number of seconds since the (POSIX) epoch (in practice
129	near the beginning of 1970, details are complicated, don't ask). This	138	somewhere near the beginning of 1970, details are complicated, don't
130	type is called C<ev_tstamp>, which is what you should use too. It usually	139	ask). This type is called C<ev_tstamp>, which is what you should use
131	aliases to the C<double> type in C. When you need to do any calculations	140	too. It usually aliases to the C<double> type in C. When you need to do
132	on it, you should treat it as some floating point value. Unlike the name	141	any calculations on it, you should treat it as some floating point value.
		142
133	component C<stamp> might indicate, it is also used for time differences	143	Unlike the name component C<stamp> might indicate, it is also used for
134	throughout libev.	144	time differences (e.g. delays) throughout libev.
135		145
136	=head1 ERROR HANDLING	146	=head1 ERROR HANDLING
137		147
138	Libev knows three classes of errors: operating system errors, usage errors	148	Libev knows three classes of errors: operating system errors, usage errors
139	and internal errors (bugs).	149	and internal errors (bugs).
…		…
163		173
164	=item ev_tstamp ev_time ()	174	=item ev_tstamp ev_time ()
165		175
166	Returns the current time as libev would use it. Please note that the	176	Returns the current time as libev would use it. Please note that the
167	C<ev_now> function is usually faster and also often returns the timestamp	177	C<ev_now> function is usually faster and also often returns the timestamp
168	you actually want to know.	178	you actually want to know. Also interesting is the combination of
		179	C<ev_update_now> and C<ev_now>.
169		180
170	=item ev_sleep (ev_tstamp interval)	181	=item ev_sleep (ev_tstamp interval)
171		182
172	Sleep for the given interval: The current thread will be blocked until	183	Sleep for the given interval: The current thread will be blocked until
173	either it is interrupted or the given time interval has passed. Basically	184	either it is interrupted or the given time interval has passed. Basically
…		…
190	as this indicates an incompatible change. Minor versions are usually	201	as this indicates an incompatible change. Minor versions are usually
191	compatible to older versions, so a larger minor version alone is usually	202	compatible to older versions, so a larger minor version alone is usually
192	not a problem.	203	not a problem.
193		204
194	Example: Make sure we haven't accidentally been linked against the wrong	205	Example: Make sure we haven't accidentally been linked against the wrong
195	version.	206	version (note, however, that this will not detect other ABI mismatches,
		207	such as LFS or reentrancy).
196		208
197	assert (("libev version mismatch",	209	assert (("libev version mismatch",
198	ev_version_major () == EV_VERSION_MAJOR	210	ev_version_major () == EV_VERSION_MAJOR
199	&& ev_version_minor () >= EV_VERSION_MINOR));	211	&& ev_version_minor () >= EV_VERSION_MINOR));
200		212
…		…
211	assert (("sorry, no epoll, no sex",	223	assert (("sorry, no epoll, no sex",
212	ev_supported_backends () & EVBACKEND_EPOLL));	224	ev_supported_backends () & EVBACKEND_EPOLL));
213		225
214	=item unsigned int ev_recommended_backends ()	226	=item unsigned int ev_recommended_backends ()
215		227
216	Return the set of all backends compiled into this binary of libev and also	228	Return the set of all backends compiled into this binary of libev and
217	recommended for this platform. This set is often smaller than the one	229	also recommended for this platform, meaning it will work for most file
		230	descriptor types. This set is often smaller than the one returned by
218	returned by C<ev_supported_backends>, as for example kqueue is broken on	231	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
219	most BSDs and will not be auto-detected unless you explicitly request it	232	and will not be auto-detected unless you explicitly request it (assuming
220	(assuming you know what you are doing). This is the set of backends that	233	you know what you are doing). This is the set of backends that libev will
221	libev will probe for if you specify no backends explicitly.	234	probe for if you specify no backends explicitly.
222		235
223	=item unsigned int ev_embeddable_backends ()	236	=item unsigned int ev_embeddable_backends ()
224		237
225	Returns the set of backends that are embeddable in other event loops. This	238	Returns the set of backends that are embeddable in other event loops. This
226	is the theoretical, all-platform, value. To find which backends	239	value is platform-specific but can include backends not available on the
227	might be supported on the current system, you would need to look at	240	current system. To find which embeddable backends might be supported on
228	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	241	the current system, you would need to look at C<ev_embeddable_backends ()
229	recommended ones.	242	& ev_supported_backends ()>, likewise for recommended ones.
230		243
231	See the description of C<ev_embed> watchers for more info.	244	See the description of C<ev_embed> watchers for more info.
232		245
233	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]	246	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]
234		247
…		…
288	...	301	...
289	ev_set_syserr_cb (fatal_error);	302	ev_set_syserr_cb (fatal_error);
290		303
291	=back	304	=back
292		305
293	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	306	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
294		307
295	An event loop is described by a C<struct ev_loop *> (the C<struct>	308	An event loop is described by a C<struct ev_loop *> (the C<struct> is
296	is I<not> optional in this case, as there is also an C<ev_loop>	309	I<not> optional in this case unless libev 3 compatibility is disabled, as
297	I<function>).	310	libev 3 had an C<ev_loop> function colliding with the struct name).
298		311
299	The library knows two types of such loops, the I<default> loop, which	312	The library knows two types of such loops, the I<default> loop, which
300	supports signals and child events, and dynamically created loops which do	313	supports child process events, and dynamically created event loops which
301	not.	314	do not.
302		315
303	=over 4	316	=over 4
304		317
305	=item struct ev_loop *ev_default_loop (unsigned int flags)	318	=item struct ev_loop *ev_default_loop (unsigned int flags)
306		319
307	This will initialise the default event loop if it hasn't been initialised	320	This returns the "default" event loop object, which is what you should
308	yet and return it. If the default loop could not be initialised, returns	321	normally use when you just need "the event loop". Event loop objects and
309	false. If it already was initialised it simply returns it (and ignores the	322	the C<flags> parameter are described in more detail in the entry for
310	flags. If that is troubling you, check C<ev_backend ()> afterwards).	323	C<ev_loop_new>.
		324
		325	If the default loop is already initialised then this function simply
		326	returns it (and ignores the flags. If that is troubling you, check
		327	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		328	flags, which should almost always be C<0>, unless the caller is also the
		329	one calling C<ev_run> or otherwise qualifies as "the main program".
311		330
312	If you don't know what event loop to use, use the one returned from this	331	If you don't know what event loop to use, use the one returned from this
313	function.	332	function (or via the C<EV_DEFAULT> macro).
314		333
315	Note that this function is I<not> thread-safe, so if you want to use it	334	Note that this function is I<not> thread-safe, so if you want to use it
316	from multiple threads, you have to lock (note also that this is unlikely,	335	from multiple threads, you have to employ some kind of mutex (note also
317	as loops cannot be shared easily between threads anyway).	336	that this case is unlikely, as loops cannot be shared easily between
		337	threads anyway).
318		338
319	The default loop is the only loop that can handle C<ev_signal> and	339	The default loop is the only loop that can handle C<ev_child> watchers,
320	C<ev_child> watchers, and to do this, it always registers a handler	340	and to do this, it always registers a handler for C<SIGCHLD>. If this is
321	for C<SIGCHLD>. If this is a problem for your application you can either	341	a problem for your application you can either create a dynamic loop with
322	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	342	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
323	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	343	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
324	C<ev_default_init>.	344
		345	Example: This is the most typical usage.
		346
		347	if (!ev_default_loop (0))
		348	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		349
		350	Example: Restrict libev to the select and poll backends, and do not allow
		351	environment settings to be taken into account:
		352
		353	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
		354
		355	=item struct ev_loop *ev_loop_new (unsigned int flags)
		356
		357	This will create and initialise a new event loop object. If the loop
		358	could not be initialised, returns false.
		359
		360	Note that this function I<is> thread-safe, and one common way to use
		361	libev with threads is indeed to create one loop per thread, and using the
		362	default loop in the "main" or "initial" thread.
325		363
326	The flags argument can be used to specify special behaviour or specific	364	The flags argument can be used to specify special behaviour or specific
327	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	365	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
328		366
329	The following flags are supported:	367	The following flags are supported:
…		…
344	useful to try out specific backends to test their performance, or to work	382	useful to try out specific backends to test their performance, or to work
345	around bugs.	383	around bugs.
346		384
347	=item C<EVFLAG_FORKCHECK>	385	=item C<EVFLAG_FORKCHECK>
348		386
349	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	387	Instead of calling C<ev_loop_fork> manually after a fork, you can also
350	a fork, you can also make libev check for a fork in each iteration by	388	make libev check for a fork in each iteration by enabling this flag.
351	enabling this flag.
352		389
353	This works by calling C<getpid ()> on every iteration of the loop,	390	This works by calling C<getpid ()> on every iteration of the loop,
354	and thus this might slow down your event loop if you do a lot of loop	391	and thus this might slow down your event loop if you do a lot of loop
355	iterations and little real work, but is usually not noticeable (on my	392	iterations and little real work, but is usually not noticeable (on my
356	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	393	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
…		…
369	When this flag is specified, then libev will not attempt to use the	406	When this flag is specified, then libev will not attempt to use the
370	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and	407	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and
371	testing, this flag can be useful to conserve inotify file descriptors, as	408	testing, this flag can be useful to conserve inotify file descriptors, as
372	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.	409	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
373		410
374	=item C<EVFLAG_NOSIGNALFD>	411	=item C<EVFLAG_SIGNALFD>
375		412
376	When this flag is specified, then libev will not attempt to use the	413	When this flag is specified, then libev will attempt to use the
377	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This is	414	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API
378	probably only useful to work around any bugs in libev. Consequently, this	415	delivers signals synchronously, which makes it both faster and might make
379	flag might go away once the signalfd functionality is considered stable,	416	it possible to get the queued signal data. It can also simplify signal
380	so it's useful mostly in environment variables and not in program code.	417	handling with threads, as long as you properly block signals in your
		418	threads that are not interested in handling them.
		419
		420	Signalfd will not be used by default as this changes your signal mask, and
		421	there are a lot of shoddy libraries and programs (glib's threadpool for
		422	example) that can't properly initialise their signal masks.
381		423
382	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	424	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
383		425
384	This is your standard select(2) backend. Not I<completely> standard, as	426	This is your standard select(2) backend. Not I<completely> standard, as
385	libev tries to roll its own fd_set with no limits on the number of fds,	427	libev tries to roll its own fd_set with no limits on the number of fds,
…		…
409		451
410	This backend maps C<EV_READ> to C<POLLIN \| POLLERR \| POLLHUP>, and	452	This backend maps C<EV_READ> to C<POLLIN \| POLLERR \| POLLHUP>, and
411	C<EV_WRITE> to C<POLLOUT \| POLLERR \| POLLHUP>.	453	C<EV_WRITE> to C<POLLOUT \| POLLERR \| POLLHUP>.
412		454
413	=item C<EVBACKEND_EPOLL> (value 4, Linux)	455	=item C<EVBACKEND_EPOLL> (value 4, Linux)
		456
		457	Use the linux-specific epoll(7) interface (for both pre- and post-2.6.9
		458	kernels).
414		459
415	For few fds, this backend is a bit little slower than poll and select,	460	For few fds, this backend is a bit little slower than poll and select,
416	but it scales phenomenally better. While poll and select usually scale	461	but it scales phenomenally better. While poll and select usually scale
417	like O(total_fds) where n is the total number of fds (or the highest fd),	462	like O(total_fds) where n is the total number of fds (or the highest fd),
418	epoll scales either O(1) or O(active_fds).	463	epoll scales either O(1) or O(active_fds).
…		…
430	of course I<doesn't>, and epoll just loves to report events for totally	475	of course I<doesn't>, and epoll just loves to report events for totally
431	I<different> file descriptors (even already closed ones, so one cannot	476	I<different> file descriptors (even already closed ones, so one cannot
432	even remove them from the set) than registered in the set (especially	477	even remove them from the set) than registered in the set (especially
433	on SMP systems). Libev tries to counter these spurious notifications by	478	on SMP systems). Libev tries to counter these spurious notifications by
434	employing an additional generation counter and comparing that against the	479	employing an additional generation counter and comparing that against the
435	events to filter out spurious ones, recreating the set when required.	480	events to filter out spurious ones, recreating the set when required. Last
		481	not least, it also refuses to work with some file descriptors which work
		482	perfectly fine with C<select> (files, many character devices...).
436		483
437	While stopping, setting and starting an I/O watcher in the same iteration	484	While stopping, setting and starting an I/O watcher in the same iteration
438	will result in some caching, there is still a system call per such	485	will result in some caching, there is still a system call per such
439	incident (because the same I<file descriptor> could point to a different	486	incident (because the same I<file descriptor> could point to a different
440	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	487	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
538	If one or more of the backend flags are or'ed into the flags value,	585	If one or more of the backend flags are or'ed into the flags value,
539	then only these backends will be tried (in the reverse order as listed	586	then only these backends will be tried (in the reverse order as listed
540	here). If none are specified, all backends in C<ev_recommended_backends	587	here). If none are specified, all backends in C<ev_recommended_backends
541	()> will be tried.	588	()> will be tried.
542		589
543	Example: This is the most typical usage.
544
545	if (!ev_default_loop (0))
546	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
547
548	Example: Restrict libev to the select and poll backends, and do not allow
549	environment settings to be taken into account:
550
551	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
552
553	Example: Use whatever libev has to offer, but make sure that kqueue is
554	used if available (warning, breaks stuff, best use only with your own
555	private event loop and only if you know the OS supports your types of
556	fds):
557
558	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);
559
560	=item struct ev_loop *ev_loop_new (unsigned int flags)
561
562	Similar to C<ev_default_loop>, but always creates a new event loop that is
563	always distinct from the default loop. Unlike the default loop, it cannot
564	handle signal and child watchers, and attempts to do so will be greeted by
565	undefined behaviour (or a failed assertion if assertions are enabled).
566
567	Note that this function I<is> thread-safe, and the recommended way to use
568	libev with threads is indeed to create one loop per thread, and using the
569	default loop in the "main" or "initial" thread.
570
571	Example: Try to create a event loop that uses epoll and nothing else.	590	Example: Try to create a event loop that uses epoll and nothing else.
572		591
573	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	592	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
574	if (!epoller)	593	if (!epoller)
575	fatal ("no epoll found here, maybe it hides under your chair");	594	fatal ("no epoll found here, maybe it hides under your chair");
576		595
		596	Example: Use whatever libev has to offer, but make sure that kqueue is
		597	used if available.
		598
		599	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () \| EVBACKEND_KQUEUE);
		600
577	=item ev_default_destroy ()	601	=item ev_loop_destroy (loop)
578		602
579	Destroys the default loop again (frees all memory and kernel state	603	Destroys an event loop object (frees all memory and kernel state
580	etc.). None of the active event watchers will be stopped in the normal	604	etc.). None of the active event watchers will be stopped in the normal
581	sense, so e.g. C<ev_is_active> might still return true. It is your	605	sense, so e.g. C<ev_is_active> might still return true. It is your
582	responsibility to either stop all watchers cleanly yourself I<before>	606	responsibility to either stop all watchers cleanly yourself I<before>
583	calling this function, or cope with the fact afterwards (which is usually	607	calling this function, or cope with the fact afterwards (which is usually
584	the easiest thing, you can just ignore the watchers and/or C<free ()> them	608	the easiest thing, you can just ignore the watchers and/or C<free ()> them
…		…
586		610
587	Note that certain global state, such as signal state (and installed signal	611	Note that certain global state, such as signal state (and installed signal
588	handlers), will not be freed by this function, and related watchers (such	612	handlers), will not be freed by this function, and related watchers (such
589	as signal and child watchers) would need to be stopped manually.	613	as signal and child watchers) would need to be stopped manually.
590		614
591	In general it is not advisable to call this function except in the	615	This function is normally used on loop objects allocated by
592	rare occasion where you really need to free e.g. the signal handling	616	C<ev_loop_new>, but it can also be used on the default loop returned by
		617	C<ev_default_loop>, in which case it is not thread-safe.
		618
		619	Note that it is not advisable to call this function on the default loop
		620	except in the rare occasion where you really need to free it's resources.
593	pipe fds. If you need dynamically allocated loops it is better to use	621	If you need dynamically allocated loops it is better to use C<ev_loop_new>
594	C<ev_loop_new> and C<ev_loop_destroy>).	622	and C<ev_loop_destroy>.
595		623
596	=item ev_loop_destroy (loop)	624	=item ev_loop_fork (loop)
597		625
598	Like C<ev_default_destroy>, but destroys an event loop created by an
599	earlier call to C<ev_loop_new>.
600
601	=item ev_default_fork ()
602
603	This function sets a flag that causes subsequent C<ev_loop> iterations	626	This function sets a flag that causes subsequent C<ev_run> iterations to
604	to reinitialise the kernel state for backends that have one. Despite the	627	reinitialise the kernel state for backends that have one. Despite the
605	name, you can call it anytime, but it makes most sense after forking, in	628	name, you can call it anytime, but it makes most sense after forking, in
606	the child process (or both child and parent, but that again makes little	629	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
607	sense). You I<must> call it in the child before using any of the libev	630	child before resuming or calling C<ev_run>.
608	functions, and it will only take effect at the next C<ev_loop> iteration.	631
		632	Again, you I<have> to call it on I<any> loop that you want to re-use after
		633	a fork, I<even if you do not plan to use the loop in the parent>. This is
		634	because some kernel interfaces cough I<kqueue> cough do funny things
		635	during fork.
609		636
610	On the other hand, you only need to call this function in the child	637	On the other hand, you only need to call this function in the child
611	process if and only if you want to use the event library in the child. If	638	process if and only if you want to use the event loop in the child. If
612	you just fork+exec, you don't have to call it at all.	639	you just fork+exec or create a new loop in the child, you don't have to
		640	call it at all (in fact, C<epoll> is so badly broken that it makes a
		641	difference, but libev will usually detect this case on its own and do a
		642	costly reset of the backend).
613		643
614	The function itself is quite fast and it's usually not a problem to call	644	The function itself is quite fast and it's usually not a problem to call
615	it just in case after a fork. To make this easy, the function will fit in	645	it just in case after a fork.
616	quite nicely into a call to C<pthread_atfork>:
617		646
		647	Example: Automate calling C<ev_loop_fork> on the default loop when
		648	using pthreads.
		649
		650	static void
		651	post_fork_child (void)
		652	{
		653	ev_loop_fork (EV_DEFAULT);
		654	}
		655
		656	...
618	pthread_atfork (0, 0, ev_default_fork);	657	pthread_atfork (0, 0, post_fork_child);
619
620	=item ev_loop_fork (loop)
621
622	Like C<ev_default_fork>, but acts on an event loop created by
623	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
624	after fork that you want to re-use in the child, and how you do this is
625	entirely your own problem.
626		658
627	=item int ev_is_default_loop (loop)	659	=item int ev_is_default_loop (loop)
628		660
629	Returns true when the given loop is, in fact, the default loop, and false	661	Returns true when the given loop is, in fact, the default loop, and false
630	otherwise.	662	otherwise.
631		663
632	=item unsigned int ev_loop_count (loop)	664	=item unsigned int ev_iteration (loop)
633		665
634	Returns the count of loop iterations for the loop, which is identical to	666	Returns the current iteration count for the event loop, which is identical
635	the number of times libev did poll for new events. It starts at C<0> and	667	to the number of times libev did poll for new events. It starts at C<0>
636	happily wraps around with enough iterations.	668	and happily wraps around with enough iterations.
637		669
638	This value can sometimes be useful as a generation counter of sorts (it	670	This value can sometimes be useful as a generation counter of sorts (it
639	"ticks" the number of loop iterations), as it roughly corresponds with	671	"ticks" the number of loop iterations), as it roughly corresponds with
640	C<ev_prepare> and C<ev_check> calls.	672	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		673	prepare and check phases.
641		674
642	=item unsigned int ev_loop_depth (loop)	675	=item unsigned int ev_depth (loop)
643		676
644	Returns the number of times C<ev_loop> was entered minus the number of	677	Returns the number of times C<ev_run> was entered minus the number of
645	times C<ev_loop> was exited, in other words, the recursion depth.	678	times C<ev_run> was exited, in other words, the recursion depth.
646		679
647	Outside C<ev_loop>, this number is zero. In a callback, this number is	680	Outside C<ev_run>, this number is zero. In a callback, this number is
648	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	681	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
649	in which case it is higher.	682	in which case it is higher.
650		683
651	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	684	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
652	etc.), doesn't count as exit.	685	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		686	ungentleman-like behaviour unless it's really convenient.
653		687
654	=item unsigned int ev_backend (loop)	688	=item unsigned int ev_backend (loop)
655		689
656	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	690	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
657	use.	691	use.
…		…
666		700
667	=item ev_now_update (loop)	701	=item ev_now_update (loop)
668		702
669	Establishes the current time by querying the kernel, updating the time	703	Establishes the current time by querying the kernel, updating the time
670	returned by C<ev_now ()> in the progress. This is a costly operation and	704	returned by C<ev_now ()> in the progress. This is a costly operation and
671	is usually done automatically within C<ev_loop ()>.	705	is usually done automatically within C<ev_run ()>.
672		706
673	This function is rarely useful, but when some event callback runs for a	707	This function is rarely useful, but when some event callback runs for a
674	very long time without entering the event loop, updating libev's idea of	708	very long time without entering the event loop, updating libev's idea of
675	the current time is a good idea.	709	the current time is a good idea.
676		710
…		…
678		712
679	=item ev_suspend (loop)	713	=item ev_suspend (loop)
680		714
681	=item ev_resume (loop)	715	=item ev_resume (loop)
682		716
683	These two functions suspend and resume a loop, for use when the loop is	717	These two functions suspend and resume an event loop, for use when the
684	not used for a while and timeouts should not be processed.	718	loop is not used for a while and timeouts should not be processed.
685		719
686	A typical use case would be an interactive program such as a game: When	720	A typical use case would be an interactive program such as a game: When
687	the user presses C<^Z> to suspend the game and resumes it an hour later it	721	the user presses C<^Z> to suspend the game and resumes it an hour later it
688	would be best to handle timeouts as if no time had actually passed while	722	would be best to handle timeouts as if no time had actually passed while
689	the program was suspended. This can be achieved by calling C<ev_suspend>	723	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
691	C<ev_resume> directly afterwards to resume timer processing.	725	C<ev_resume> directly afterwards to resume timer processing.
692		726
693	Effectively, all C<ev_timer> watchers will be delayed by the time spend	727	Effectively, all C<ev_timer> watchers will be delayed by the time spend
694	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	728	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
695	will be rescheduled (that is, they will lose any events that would have	729	will be rescheduled (that is, they will lose any events that would have
696	occured while suspended).	730	occurred while suspended).
697		731
698	After calling C<ev_suspend> you B<must not> call I<any> function on the	732	After calling C<ev_suspend> you B<must not> call I<any> function on the
699	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	733	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
700	without a previous call to C<ev_suspend>.	734	without a previous call to C<ev_suspend>.
701		735
702	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	736	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
703	event loop time (see C<ev_now_update>).	737	event loop time (see C<ev_now_update>).
704		738
705	=item ev_loop (loop, int flags)	739	=item ev_run (loop, int flags)
706		740
707	Finally, this is it, the event handler. This function usually is called	741	Finally, this is it, the event handler. This function usually is called
708	after you initialised all your watchers and you want to start handling	742	after you have initialised all your watchers and you want to start
709	events.	743	handling events. It will ask the operating system for any new events, call
		744	the watcher callbacks, an then repeat the whole process indefinitely: This
		745	is why event loops are called I<loops>.
710		746
711	If the flags argument is specified as C<0>, it will not return until	747	If the flags argument is specified as C<0>, it will keep handling events
712	either no event watchers are active anymore or C<ev_unloop> was called.	748	until either no event watchers are active anymore or C<ev_break> was
		749	called.
713		750
714	Please note that an explicit C<ev_unloop> is usually better than	751	Please note that an explicit C<ev_break> is usually better than
715	relying on all watchers to be stopped when deciding when a program has	752	relying on all watchers to be stopped when deciding when a program has
716	finished (especially in interactive programs), but having a program	753	finished (especially in interactive programs), but having a program
717	that automatically loops as long as it has to and no longer by virtue	754	that automatically loops as long as it has to and no longer by virtue
718	of relying on its watchers stopping correctly, that is truly a thing of	755	of relying on its watchers stopping correctly, that is truly a thing of
719	beauty.	756	beauty.
720		757
721	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	758	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
722	those events and any already outstanding ones, but will not block your	759	those events and any already outstanding ones, but will not wait and
723	process in case there are no events and will return after one iteration of	760	block your process in case there are no events and will return after one
724	the loop.	761	iteration of the loop. This is sometimes useful to poll and handle new
		762	events while doing lengthy calculations, to keep the program responsive.
725		763
726	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	764	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
727	necessary) and will handle those and any already outstanding ones. It	765	necessary) and will handle those and any already outstanding ones. It
728	will block your process until at least one new event arrives (which could	766	will block your process until at least one new event arrives (which could
729	be an event internal to libev itself, so there is no guarantee that a	767	be an event internal to libev itself, so there is no guarantee that a
730	user-registered callback will be called), and will return after one	768	user-registered callback will be called), and will return after one
731	iteration of the loop.	769	iteration of the loop.
732		770
733	This is useful if you are waiting for some external event in conjunction	771	This is useful if you are waiting for some external event in conjunction
734	with something not expressible using other libev watchers (i.e. "roll your	772	with something not expressible using other libev watchers (i.e. "roll your
735	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	773	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
736	usually a better approach for this kind of thing.	774	usually a better approach for this kind of thing.
737		775
738	Here are the gory details of what C<ev_loop> does:	776	Here are the gory details of what C<ev_run> does:
739		777
		778	- Increment loop depth.
		779	- Reset the ev_break status.
740	- Before the first iteration, call any pending watchers.	780	- Before the first iteration, call any pending watchers.
		781	LOOP:
741	* If EVFLAG_FORKCHECK was used, check for a fork.	782	- If EVFLAG_FORKCHECK was used, check for a fork.
742	- If a fork was detected (by any means), queue and call all fork watchers.	783	- If a fork was detected (by any means), queue and call all fork watchers.
743	- Queue and call all prepare watchers.	784	- Queue and call all prepare watchers.
		785	- If ev_break was called, goto FINISH.
744	- If we have been forked, detach and recreate the kernel state	786	- If we have been forked, detach and recreate the kernel state
745	as to not disturb the other process.	787	as to not disturb the other process.
746	- Update the kernel state with all outstanding changes.	788	- Update the kernel state with all outstanding changes.
747	- Update the "event loop time" (ev_now ()).	789	- Update the "event loop time" (ev_now ()).
748	- Calculate for how long to sleep or block, if at all	790	- Calculate for how long to sleep or block, if at all
749	(active idle watchers, EVLOOP_NONBLOCK or not having	791	(active idle watchers, EVRUN_NOWAIT or not having
750	any active watchers at all will result in not sleeping).	792	any active watchers at all will result in not sleeping).
751	- Sleep if the I/O and timer collect interval say so.	793	- Sleep if the I/O and timer collect interval say so.
		794	- Increment loop iteration counter.
752	- Block the process, waiting for any events.	795	- Block the process, waiting for any events.
753	- Queue all outstanding I/O (fd) events.	796	- Queue all outstanding I/O (fd) events.
754	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	797	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
755	- Queue all expired timers.	798	- Queue all expired timers.
756	- Queue all expired periodics.	799	- Queue all expired periodics.
757	- Unless any events are pending now, queue all idle watchers.	800	- Queue all idle watchers with priority higher than that of pending events.
758	- Queue all check watchers.	801	- Queue all check watchers.
759	- Call all queued watchers in reverse order (i.e. check watchers first).	802	- Call all queued watchers in reverse order (i.e. check watchers first).
760	Signals and child watchers are implemented as I/O watchers, and will	803	Signals and child watchers are implemented as I/O watchers, and will
761	be handled here by queueing them when their watcher gets executed.	804	be handled here by queueing them when their watcher gets executed.
762	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	805	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
763	were used, or there are no active watchers, return, otherwise	806	were used, or there are no active watchers, goto FINISH, otherwise
764	continue with step *.	807	continue with step LOOP.
		808	FINISH:
		809	- Reset the ev_break status iff it was EVBREAK_ONE.
		810	- Decrement the loop depth.
		811	- Return.
765		812
766	Example: Queue some jobs and then loop until no events are outstanding	813	Example: Queue some jobs and then loop until no events are outstanding
767	anymore.	814	anymore.
768		815
769	... queue jobs here, make sure they register event watchers as long	816	... queue jobs here, make sure they register event watchers as long
770	... as they still have work to do (even an idle watcher will do..)	817	... as they still have work to do (even an idle watcher will do..)
771	ev_loop (my_loop, 0);	818	ev_run (my_loop, 0);
772	... jobs done or somebody called unloop. yeah!	819	... jobs done or somebody called unloop. yeah!
773		820
774	=item ev_unloop (loop, how)	821	=item ev_break (loop, how)
775		822
776	Can be used to make a call to C<ev_loop> return early (but only after it	823	Can be used to make a call to C<ev_run> return early (but only after it
777	has processed all outstanding events). The C<how> argument must be either	824	has processed all outstanding events). The C<how> argument must be either
778	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	825	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
779	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	826	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
780		827
781	This "unloop state" will be cleared when entering C<ev_loop> again.	828	This "unloop state" will be cleared when entering C<ev_run> again.
782		829
783	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	830	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
784		831
785	=item ev_ref (loop)	832	=item ev_ref (loop)
786		833
787	=item ev_unref (loop)	834	=item ev_unref (loop)
788		835
789	Ref/unref can be used to add or remove a reference count on the event	836	Ref/unref can be used to add or remove a reference count on the event
790	loop: Every watcher keeps one reference, and as long as the reference	837	loop: Every watcher keeps one reference, and as long as the reference
791	count is nonzero, C<ev_loop> will not return on its own.	838	count is nonzero, C<ev_run> will not return on its own.
792		839
793	If you have a watcher you never unregister that should not keep C<ev_loop>	840	This is useful when you have a watcher that you never intend to
794	from returning, call ev_unref() after starting, and ev_ref() before	841	unregister, but that nevertheless should not keep C<ev_run> from
		842	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
795	stopping it.	843	before stopping it.
796		844
797	As an example, libev itself uses this for its internal signal pipe: It	845	As an example, libev itself uses this for its internal signal pipe: It
798	is not visible to the libev user and should not keep C<ev_loop> from	846	is not visible to the libev user and should not keep C<ev_run> from
799	exiting if no event watchers registered by it are active. It is also an	847	exiting if no event watchers registered by it are active. It is also an
800	excellent way to do this for generic recurring timers or from within	848	excellent way to do this for generic recurring timers or from within
801	third-party libraries. Just remember to I<unref after start> and I<ref	849	third-party libraries. Just remember to I<unref after start> and I<ref
802	before stop> (but only if the watcher wasn't active before, or was active	850	before stop> (but only if the watcher wasn't active before, or was active
803	before, respectively. Note also that libev might stop watchers itself	851	before, respectively. Note also that libev might stop watchers itself
804	(e.g. non-repeating timers) in which case you have to C<ev_ref>	852	(e.g. non-repeating timers) in which case you have to C<ev_ref>
805	in the callback).	853	in the callback).
806		854
807	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	855	Example: Create a signal watcher, but keep it from keeping C<ev_run>
808	running when nothing else is active.	856	running when nothing else is active.
809		857
810	ev_signal exitsig;	858	ev_signal exitsig;
811	ev_signal_init (&exitsig, sig_cb, SIGINT);	859	ev_signal_init (&exitsig, sig_cb, SIGINT);
812	ev_signal_start (loop, &exitsig);	860	ev_signal_start (loop, &exitsig);
…		…
857	usually doesn't make much sense to set it to a lower value than C<0.01>,	905	usually doesn't make much sense to set it to a lower value than C<0.01>,
858	as this approaches the timing granularity of most systems. Note that if	906	as this approaches the timing granularity of most systems. Note that if
859	you do transactions with the outside world and you can't increase the	907	you do transactions with the outside world and you can't increase the
860	parallelity, then this setting will limit your transaction rate (if you	908	parallelity, then this setting will limit your transaction rate (if you
861	need to poll once per transaction and the I/O collect interval is 0.01,	909	need to poll once per transaction and the I/O collect interval is 0.01,
862	then you can't do more than 100 transations per second).	910	then you can't do more than 100 transactions per second).
863		911
864	Setting the I<timeout collect interval> can improve the opportunity for	912	Setting the I<timeout collect interval> can improve the opportunity for
865	saving power, as the program will "bundle" timer callback invocations that	913	saving power, as the program will "bundle" timer callback invocations that
866	are "near" in time together, by delaying some, thus reducing the number of	914	are "near" in time together, by delaying some, thus reducing the number of
867	times the process sleeps and wakes up again. Another useful technique to	915	times the process sleeps and wakes up again. Another useful technique to
…		…
875	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	923	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
876		924
877	=item ev_invoke_pending (loop)	925	=item ev_invoke_pending (loop)
878		926
879	This call will simply invoke all pending watchers while resetting their	927	This call will simply invoke all pending watchers while resetting their
880	pending state. Normally, C<ev_loop> does this automatically when required,	928	pending state. Normally, C<ev_run> does this automatically when required,
881	but when overriding the invoke callback this call comes handy.	929	but when overriding the invoke callback this call comes handy. This
		930	function can be invoked from a watcher - this can be useful for example
		931	when you want to do some lengthy calculation and want to pass further
		932	event handling to another thread (you still have to make sure only one
		933	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
882		934
883	=item int ev_pending_count (loop)	935	=item int ev_pending_count (loop)
884		936
885	Returns the number of pending watchers - zero indicates that no watchers	937	Returns the number of pending watchers - zero indicates that no watchers
886	are pending.	938	are pending.
887		939
888	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	940	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
889		941
890	This overrides the invoke pending functionality of the loop: Instead of	942	This overrides the invoke pending functionality of the loop: Instead of
891	invoking all pending watchers when there are any, C<ev_loop> will call	943	invoking all pending watchers when there are any, C<ev_run> will call
892	this callback instead. This is useful, for example, when you want to	944	this callback instead. This is useful, for example, when you want to
893	invoke the actual watchers inside another context (another thread etc.).	945	invoke the actual watchers inside another context (another thread etc.).
894		946
895	If you want to reset the callback, use C<ev_invoke_pending> as new	947	If you want to reset the callback, use C<ev_invoke_pending> as new
896	callback.	948	callback.
…		…
899		951
900	Sometimes you want to share the same loop between multiple threads. This	952	Sometimes you want to share the same loop between multiple threads. This
901	can be done relatively simply by putting mutex_lock/unlock calls around	953	can be done relatively simply by putting mutex_lock/unlock calls around
902	each call to a libev function.	954	each call to a libev function.
903		955
904	However, C<ev_loop> can run an indefinite time, so it is not feasible to	956	However, C<ev_run> can run an indefinite time, so it is not feasible
905	wait for it to return. One way around this is to wake up the loop via	957	to wait for it to return. One way around this is to wake up the event
906	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	958	loop via C<ev_break> and C<av_async_send>, another way is to set these
907	and I<acquire> callbacks on the loop.	959	I<release> and I<acquire> callbacks on the loop.
908		960
909	When set, then C<release> will be called just before the thread is	961	When set, then C<release> will be called just before the thread is
910	suspended waiting for new events, and C<acquire> is called just	962	suspended waiting for new events, and C<acquire> is called just
911	afterwards.	963	afterwards.
912		964
…		…
915		967
916	While event loop modifications are allowed between invocations of	968	While event loop modifications are allowed between invocations of
917	C<release> and C<acquire> (that's their only purpose after all), no	969	C<release> and C<acquire> (that's their only purpose after all), no
918	modifications done will affect the event loop, i.e. adding watchers will	970	modifications done will affect the event loop, i.e. adding watchers will
919	have no effect on the set of file descriptors being watched, or the time	971	have no effect on the set of file descriptors being watched, or the time
920	waited. USe an C<ev_async> watcher to wake up C<ev_loop> when you want it	972	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
921	to take note of any changes you made.	973	to take note of any changes you made.
922		974
923	In theory, threads executing C<ev_loop> will be async-cancel safe between	975	In theory, threads executing C<ev_run> will be async-cancel safe between
924	invocations of C<release> and C<acquire>.	976	invocations of C<release> and C<acquire>.
925		977
926	See also the locking example in the C<THREADS> section later in this	978	See also the locking example in the C<THREADS> section later in this
927	document.	979	document.
928		980
…		…
937	These two functions can be used to associate arbitrary data with a loop,	989	These two functions can be used to associate arbitrary data with a loop,
938	and are intended solely for the C<invoke_pending_cb>, C<release> and	990	and are intended solely for the C<invoke_pending_cb>, C<release> and
939	C<acquire> callbacks described above, but of course can be (ab-)used for	991	C<acquire> callbacks described above, but of course can be (ab-)used for
940	any other purpose as well.	992	any other purpose as well.
941		993
942	=item ev_loop_verify (loop)	994	=item ev_verify (loop)
943		995
944	This function only does something when C<EV_VERIFY> support has been	996	This function only does something when C<EV_VERIFY> support has been
945	compiled in, which is the default for non-minimal builds. It tries to go	997	compiled in, which is the default for non-minimal builds. It tries to go
946	through all internal structures and checks them for validity. If anything	998	through all internal structures and checks them for validity. If anything
947	is found to be inconsistent, it will print an error message to standard	999	is found to be inconsistent, it will print an error message to standard
…		…
958		1010
959	In the following description, uppercase C<TYPE> in names stands for the	1011	In the following description, uppercase C<TYPE> in names stands for the
960	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1012	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
961	watchers and C<ev_io_start> for I/O watchers.	1013	watchers and C<ev_io_start> for I/O watchers.
962		1014
963	A watcher is a structure that you create and register to record your	1015	A watcher is an opaque structure that you allocate and register to record
964	interest in some event. For instance, if you want to wait for STDIN to	1016	your interest in some event. To make a concrete example, imagine you want
965	become readable, you would create an C<ev_io> watcher for that:	1017	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1018	for that:
966		1019
967	static void my_cb (struct ev_loop loop, ev_io w, int revents)	1020	static void my_cb (struct ev_loop loop, ev_io w, int revents)
968	{	1021	{
969	ev_io_stop (w);	1022	ev_io_stop (w);
970	ev_unloop (loop, EVUNLOOP_ALL);	1023	ev_break (loop, EVBREAK_ALL);
971	}	1024	}
972		1025
973	struct ev_loop *loop = ev_default_loop (0);	1026	struct ev_loop *loop = ev_default_loop (0);
974		1027
975	ev_io stdin_watcher;	1028	ev_io stdin_watcher;
976		1029
977	ev_init (&stdin_watcher, my_cb);	1030	ev_init (&stdin_watcher, my_cb);
978	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1031	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
979	ev_io_start (loop, &stdin_watcher);	1032	ev_io_start (loop, &stdin_watcher);
980		1033
981	ev_loop (loop, 0);	1034	ev_run (loop, 0);
982		1035
983	As you can see, you are responsible for allocating the memory for your	1036	As you can see, you are responsible for allocating the memory for your
984	watcher structures (and it is I<usually> a bad idea to do this on the	1037	watcher structures (and it is I<usually> a bad idea to do this on the
985	stack).	1038	stack).
986		1039
987	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1040	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
988	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1041	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
989		1042
990	Each watcher structure must be initialised by a call to C<ev_init	1043	Each watcher structure must be initialised by a call to C<ev_init (watcher
991	(watcher *, callback)>, which expects a callback to be provided. This	1044	*, callback)>, which expects a callback to be provided. This callback is
992	callback gets invoked each time the event occurs (or, in the case of I/O	1045	invoked each time the event occurs (or, in the case of I/O watchers, each
993	watchers, each time the event loop detects that the file descriptor given	1046	time the event loop detects that the file descriptor given is readable
994	is readable and/or writable).	1047	and/or writable).
995		1048
996	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1049	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
997	macro to configure it, with arguments specific to the watcher type. There	1050	macro to configure it, with arguments specific to the watcher type. There
998	is also a macro to combine initialisation and setting in one call: C<<	1051	is also a macro to combine initialisation and setting in one call: C<<
999	ev_TYPE_init (watcher *, callback, ...) >>.	1052	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1022	=item C<EV_WRITE>	1075	=item C<EV_WRITE>
1023		1076
1024	The file descriptor in the C<ev_io> watcher has become readable and/or	1077	The file descriptor in the C<ev_io> watcher has become readable and/or
1025	writable.	1078	writable.
1026		1079
1027	=item C<EV_TIMEOUT>	1080	=item C<EV_TIMER>
1028		1081
1029	The C<ev_timer> watcher has timed out.	1082	The C<ev_timer> watcher has timed out.
1030		1083
1031	=item C<EV_PERIODIC>	1084	=item C<EV_PERIODIC>
1032		1085
…		…
1050		1103
1051	=item C<EV_PREPARE>	1104	=item C<EV_PREPARE>
1052		1105
1053	=item C<EV_CHECK>	1106	=item C<EV_CHECK>
1054		1107
1055	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1108	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1056	to gather new events, and all C<ev_check> watchers are invoked just after	1109	to gather new events, and all C<ev_check> watchers are invoked just after
1057	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1110	C<ev_run> has gathered them, but before it invokes any callbacks for any
1058	received events. Callbacks of both watcher types can start and stop as	1111	received events. Callbacks of both watcher types can start and stop as
1059	many watchers as they want, and all of them will be taken into account	1112	many watchers as they want, and all of them will be taken into account
1060	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1113	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1061	C<ev_loop> from blocking).	1114	C<ev_run> from blocking).
1062		1115
1063	=item C<EV_EMBED>	1116	=item C<EV_EMBED>
1064		1117
1065	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1118	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1066		1119
1067	=item C<EV_FORK>	1120	=item C<EV_FORK>
1068		1121
1069	The event loop has been resumed in the child process after fork (see	1122	The event loop has been resumed in the child process after fork (see
1070	C<ev_fork>).	1123	C<ev_fork>).
		1124
		1125	=item C<EV_CLEANUP>
		1126
		1127	The event loop is about to be destroyed (see C<ev_cleanup>).
1071		1128
1072	=item C<EV_ASYNC>	1129	=item C<EV_ASYNC>
1073		1130
1074	The given async watcher has been asynchronously notified (see C<ev_async>).	1131	The given async watcher has been asynchronously notified (see C<ev_async>).
1075		1132
…		…
1122		1179
1123	ev_io w;	1180	ev_io w;
1124	ev_init (&w, my_cb);	1181	ev_init (&w, my_cb);
1125	ev_io_set (&w, STDIN_FILENO, EV_READ);	1182	ev_io_set (&w, STDIN_FILENO, EV_READ);
1126		1183
1127	=item C<ev_TYPE_set> (ev_TYPE *, [args])	1184	=item C<ev_TYPE_set> (ev_TYPE *watcher, [args])
1128		1185
1129	This macro initialises the type-specific parts of a watcher. You need to	1186	This macro initialises the type-specific parts of a watcher. You need to
1130	call C<ev_init> at least once before you call this macro, but you can	1187	call C<ev_init> at least once before you call this macro, but you can
1131	call C<ev_TYPE_set> any number of times. You must not, however, call this	1188	call C<ev_TYPE_set> any number of times. You must not, however, call this
1132	macro on a watcher that is active (it can be pending, however, which is a	1189	macro on a watcher that is active (it can be pending, however, which is a
…		…
1145		1202
1146	Example: Initialise and set an C<ev_io> watcher in one step.	1203	Example: Initialise and set an C<ev_io> watcher in one step.
1147		1204
1148	ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);	1205	ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
1149		1206
1150	=item C<ev_TYPE_start> (loop , ev_TYPE watcher)	1207	=item C<ev_TYPE_start> (loop, ev_TYPE *watcher)
1151		1208
1152	Starts (activates) the given watcher. Only active watchers will receive	1209	Starts (activates) the given watcher. Only active watchers will receive
1153	events. If the watcher is already active nothing will happen.	1210	events. If the watcher is already active nothing will happen.
1154		1211
1155	Example: Start the C<ev_io> watcher that is being abused as example in this	1212	Example: Start the C<ev_io> watcher that is being abused as example in this
1156	whole section.	1213	whole section.
1157		1214
1158	ev_io_start (EV_DEFAULT_UC, &w);	1215	ev_io_start (EV_DEFAULT_UC, &w);
1159		1216
1160	=item C<ev_TYPE_stop> (loop , ev_TYPE watcher)	1217	=item C<ev_TYPE_stop> (loop, ev_TYPE *watcher)
1161		1218
1162	Stops the given watcher if active, and clears the pending status (whether	1219	Stops the given watcher if active, and clears the pending status (whether
1163	the watcher was active or not).	1220	the watcher was active or not).
1164		1221
1165	It is possible that stopped watchers are pending - for example,	1222	It is possible that stopped watchers are pending - for example,
…		…
1190	=item ev_cb_set (ev_TYPE *watcher, callback)	1247	=item ev_cb_set (ev_TYPE *watcher, callback)
1191		1248
1192	Change the callback. You can change the callback at virtually any time	1249	Change the callback. You can change the callback at virtually any time
1193	(modulo threads).	1250	(modulo threads).
1194		1251
1195	=item ev_set_priority (ev_TYPE *watcher, priority)	1252	=item ev_set_priority (ev_TYPE *watcher, int priority)
1196		1253
1197	=item int ev_priority (ev_TYPE *watcher)	1254	=item int ev_priority (ev_TYPE *watcher)
1198		1255
1199	Set and query the priority of the watcher. The priority is a small	1256	Set and query the priority of the watcher. The priority is a small
1200	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>	1257	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
…		…
1232	watcher isn't pending it does nothing and returns C<0>.	1289	watcher isn't pending it does nothing and returns C<0>.
1233		1290
1234	Sometimes it can be useful to "poll" a watcher instead of waiting for its	1291	Sometimes it can be useful to "poll" a watcher instead of waiting for its
1235	callback to be invoked, which can be accomplished with this function.	1292	callback to be invoked, which can be accomplished with this function.
1236		1293
		1294	=item ev_feed_event (loop, ev_TYPE *watcher, int revents)
		1295
		1296	Feeds the given event set into the event loop, as if the specified event
		1297	had happened for the specified watcher (which must be a pointer to an
		1298	initialised but not necessarily started event watcher). Obviously you must
		1299	not free the watcher as long as it has pending events.
		1300
		1301	Stopping the watcher, letting libev invoke it, or calling
		1302	C<ev_clear_pending> will clear the pending event, even if the watcher was
		1303	not started in the first place.
		1304
		1305	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
		1306	functions that do not need a watcher.
		1307
1237	=back	1308	=back
1238
1239		1309
1240	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1310	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
1241		1311
1242	Each watcher has, by default, a member C<void *data> that you can change	1312	Each watcher has, by default, a member C<void *data> that you can change
1243	and read at any time: libev will completely ignore it. This can be used	1313	and read at any time: libev will completely ignore it. This can be used
…		…
1299	t2_cb (EV_P_ ev_timer *w, int revents)	1369	t2_cb (EV_P_ ev_timer *w, int revents)
1300	{	1370	{
1301	struct my_biggy big = (struct my_biggy *)	1371	struct my_biggy big = (struct my_biggy *)
1302	(((char *)w) - offsetof (struct my_biggy, t2));	1372	(((char *)w) - offsetof (struct my_biggy, t2));
1303	}	1373	}
		1374
		1375	=head2 WATCHER STATES
		1376
		1377	There are various watcher states mentioned throughout this manual -
		1378	active, pending and so on. In this section these states and the rules to
		1379	transition between them will be described in more detail - and while these
		1380	rules might look complicated, they usually do "the right thing".
		1381
		1382	=over 4
		1383
		1384	=item initialiased
		1385
		1386	Before a watcher can be registered with the event looop it has to be
		1387	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1388	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1389
		1390	In this state it is simply some block of memory that is suitable for use
		1391	in an event loop. It can be moved around, freed, reused etc. at will.
		1392
		1393	=item started/running/active
		1394
		1395	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1396	property of the event loop, and is actively waiting for events. While in
		1397	this state it cannot be accessed (except in a few documented ways), moved,
		1398	freed or anything else - the only legal thing is to keep a pointer to it,
		1399	and call libev functions on it that are documented to work on active watchers.
		1400
		1401	=item pending
		1402
		1403	If a watcher is active and libev determines that an event it is interested
		1404	in has occurred (such as a timer expiring), it will become pending. It will
		1405	stay in this pending state until either it is stopped or its callback is
		1406	about to be invoked, so it is not normally pending inside the watcher
		1407	callback.
		1408
		1409	The watcher might or might not be active while it is pending (for example,
		1410	an expired non-repeating timer can be pending but no longer active). If it
		1411	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1412	but it is still property of the event loop at this time, so cannot be
		1413	moved, freed or reused. And if it is active the rules described in the
		1414	previous item still apply.
		1415
		1416	It is also possible to feed an event on a watcher that is not active (e.g.
		1417	via C<ev_feed_event>), in which case it becomes pending without being
		1418	active.
		1419
		1420	=item stopped
		1421
		1422	A watcher can be stopped implicitly by libev (in which case it might still
		1423	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1424	latter will clear any pending state the watcher might be in, regardless
		1425	of whether it was active or not, so stopping a watcher explicitly before
		1426	freeing it is often a good idea.
		1427
		1428	While stopped (and not pending) the watcher is essentially in the
		1429	initialised state, that is it can be reused, moved, modified in any way
		1430	you wish.
		1431
		1432	=back
1304		1433
1305	=head2 WATCHER PRIORITY MODELS	1434	=head2 WATCHER PRIORITY MODELS
1306		1435
1307	Many event loops support I<watcher priorities>, which are usually small	1436	Many event loops support I<watcher priorities>, which are usually small
1308	integers that influence the ordering of event callback invocation	1437	integers that influence the ordering of event callback invocation
…		…
1351		1480
1352	For example, to emulate how many other event libraries handle priorities,	1481	For example, to emulate how many other event libraries handle priorities,
1353	you can associate an C<ev_idle> watcher to each such watcher, and in	1482	you can associate an C<ev_idle> watcher to each such watcher, and in
1354	the normal watcher callback, you just start the idle watcher. The real	1483	the normal watcher callback, you just start the idle watcher. The real
1355	processing is done in the idle watcher callback. This causes libev to	1484	processing is done in the idle watcher callback. This causes libev to
1356	continously poll and process kernel event data for the watcher, but when	1485	continuously poll and process kernel event data for the watcher, but when
1357	the lock-out case is known to be rare (which in turn is rare :), this is	1486	the lock-out case is known to be rare (which in turn is rare :), this is
1358	workable.	1487	workable.
1359		1488
1360	Usually, however, the lock-out model implemented that way will perform	1489	Usually, however, the lock-out model implemented that way will perform
1361	miserably under the type of load it was designed to handle. In that case,	1490	miserably under the type of load it was designed to handle. In that case,
…		…
1375	{	1504	{
1376	// stop the I/O watcher, we received the event, but	1505	// stop the I/O watcher, we received the event, but
1377	// are not yet ready to handle it.	1506	// are not yet ready to handle it.
1378	ev_io_stop (EV_A_ w);	1507	ev_io_stop (EV_A_ w);
1379		1508
1380	// start the idle watcher to ahndle the actual event.	1509	// start the idle watcher to handle the actual event.
1381	// it will not be executed as long as other watchers	1510	// it will not be executed as long as other watchers
1382	// with the default priority are receiving events.	1511	// with the default priority are receiving events.
1383	ev_idle_start (EV_A_ &idle);	1512	ev_idle_start (EV_A_ &idle);
1384	}	1513	}
1385		1514
…		…
1439		1568
1440	If you cannot use non-blocking mode, then force the use of a	1569	If you cannot use non-blocking mode, then force the use of a
1441	known-to-be-good backend (at the time of this writing, this includes only	1570	known-to-be-good backend (at the time of this writing, this includes only
1442	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1571	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1443	descriptors for which non-blocking operation makes no sense (such as	1572	descriptors for which non-blocking operation makes no sense (such as
1444	files) - libev doesn't guarentee any specific behaviour in that case.	1573	files) - libev doesn't guarantee any specific behaviour in that case.
1445		1574
1446	Another thing you have to watch out for is that it is quite easy to	1575	Another thing you have to watch out for is that it is quite easy to
1447	receive "spurious" readiness notifications, that is your callback might	1576	receive "spurious" readiness notifications, that is your callback might
1448	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1577	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1449	because there is no data. Not only are some backends known to create a	1578	because there is no data. Not only are some backends known to create a
…		…
1514		1643
1515	So when you encounter spurious, unexplained daemon exits, make sure you	1644	So when you encounter spurious, unexplained daemon exits, make sure you
1516	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1645	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1517	somewhere, as that would have given you a big clue).	1646	somewhere, as that would have given you a big clue).
1518		1647
		1648	=head3 The special problem of accept()ing when you can't
		1649
		1650	Many implementations of the POSIX C<accept> function (for example,
		1651	found in post-2004 Linux) have the peculiar behaviour of not removing a
		1652	connection from the pending queue in all error cases.
		1653
		1654	For example, larger servers often run out of file descriptors (because
		1655	of resource limits), causing C<accept> to fail with C<ENFILE> but not
		1656	rejecting the connection, leading to libev signalling readiness on
		1657	the next iteration again (the connection still exists after all), and
		1658	typically causing the program to loop at 100% CPU usage.
		1659
		1660	Unfortunately, the set of errors that cause this issue differs between
		1661	operating systems, there is usually little the app can do to remedy the
		1662	situation, and no known thread-safe method of removing the connection to
		1663	cope with overload is known (to me).
		1664
		1665	One of the easiest ways to handle this situation is to just ignore it
		1666	- when the program encounters an overload, it will just loop until the
		1667	situation is over. While this is a form of busy waiting, no OS offers an
		1668	event-based way to handle this situation, so it's the best one can do.
		1669
		1670	A better way to handle the situation is to log any errors other than
		1671	C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
		1672	messages, and continue as usual, which at least gives the user an idea of
		1673	what could be wrong ("raise the ulimit!"). For extra points one could stop
		1674	the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
		1675	usage.
		1676
		1677	If your program is single-threaded, then you could also keep a dummy file
		1678	descriptor for overload situations (e.g. by opening F</dev/null>), and
		1679	when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
		1680	close that fd, and create a new dummy fd. This will gracefully refuse
		1681	clients under typical overload conditions.
		1682
		1683	The last way to handle it is to simply log the error and C<exit>, as
		1684	is often done with C<malloc> failures, but this results in an easy
		1685	opportunity for a DoS attack.
1519		1686
1520	=head3 Watcher-Specific Functions	1687	=head3 Watcher-Specific Functions
1521		1688
1522	=over 4	1689	=over 4
1523		1690
…		…
1555	...	1722	...
1556	struct ev_loop *loop = ev_default_init (0);	1723	struct ev_loop *loop = ev_default_init (0);
1557	ev_io stdin_readable;	1724	ev_io stdin_readable;
1558	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1725	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1559	ev_io_start (loop, &stdin_readable);	1726	ev_io_start (loop, &stdin_readable);
1560	ev_loop (loop, 0);	1727	ev_run (loop, 0);
1561		1728
1562		1729
1563	=head2 C<ev_timer> - relative and optionally repeating timeouts	1730	=head2 C<ev_timer> - relative and optionally repeating timeouts
1564		1731
1565	Timer watchers are simple relative timers that generate an event after a	1732	Timer watchers are simple relative timers that generate an event after a
…		…
1574	The callback is guaranteed to be invoked only I<after> its timeout has	1741	The callback is guaranteed to be invoked only I<after> its timeout has
1575	passed (not I<at>, so on systems with very low-resolution clocks this	1742	passed (not I<at>, so on systems with very low-resolution clocks this
1576	might introduce a small delay). If multiple timers become ready during the	1743	might introduce a small delay). If multiple timers become ready during the
1577	same loop iteration then the ones with earlier time-out values are invoked	1744	same loop iteration then the ones with earlier time-out values are invoked
1578	before ones of the same priority with later time-out values (but this is	1745	before ones of the same priority with later time-out values (but this is
1579	no longer true when a callback calls C<ev_loop> recursively).	1746	no longer true when a callback calls C<ev_run> recursively).
1580		1747
1581	=head3 Be smart about timeouts	1748	=head3 Be smart about timeouts
1582		1749
1583	Many real-world problems involve some kind of timeout, usually for error	1750	Many real-world problems involve some kind of timeout, usually for error
1584	recovery. A typical example is an HTTP request - if the other side hangs,	1751	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1670	ev_tstamp timeout = last_activity + 60.;	1837	ev_tstamp timeout = last_activity + 60.;
1671		1838
1672	// if last_activity + 60. is older than now, we did time out	1839	// if last_activity + 60. is older than now, we did time out
1673	if (timeout < now)	1840	if (timeout < now)
1674	{	1841	{
1675	// timeout occured, take action	1842	// timeout occurred, take action
1676	}	1843	}
1677	else	1844	else
1678	{	1845	{
1679	// callback was invoked, but there was some activity, re-arm	1846	// callback was invoked, but there was some activity, re-arm
1680	// the watcher to fire in last_activity + 60, which is	1847	// the watcher to fire in last_activity + 60, which is
…		…
1702	to the current time (meaning we just have some activity :), then call the	1869	to the current time (meaning we just have some activity :), then call the
1703	callback, which will "do the right thing" and start the timer:	1870	callback, which will "do the right thing" and start the timer:
1704		1871
1705	ev_init (timer, callback);	1872	ev_init (timer, callback);
1706	last_activity = ev_now (loop);	1873	last_activity = ev_now (loop);
1707	callback (loop, timer, EV_TIMEOUT);	1874	callback (loop, timer, EV_TIMER);
1708		1875
1709	And when there is some activity, simply store the current time in	1876	And when there is some activity, simply store the current time in
1710	C<last_activity>, no libev calls at all:	1877	C<last_activity>, no libev calls at all:
1711		1878
1712	last_actiivty = ev_now (loop);	1879	last_activity = ev_now (loop);
1713		1880
1714	This technique is slightly more complex, but in most cases where the	1881	This technique is slightly more complex, but in most cases where the
1715	time-out is unlikely to be triggered, much more efficient.	1882	time-out is unlikely to be triggered, much more efficient.
1716		1883
1717	Changing the timeout is trivial as well (if it isn't hard-coded in the	1884	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1755		1922
1756	=head3 The special problem of time updates	1923	=head3 The special problem of time updates
1757		1924
1758	Establishing the current time is a costly operation (it usually takes at	1925	Establishing the current time is a costly operation (it usually takes at
1759	least two system calls): EV therefore updates its idea of the current	1926	least two system calls): EV therefore updates its idea of the current
1760	time only before and after C<ev_loop> collects new events, which causes a	1927	time only before and after C<ev_run> collects new events, which causes a
1761	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1928	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1762	lots of events in one iteration.	1929	lots of events in one iteration.
1763		1930
1764	The relative timeouts are calculated relative to the C<ev_now ()>	1931	The relative timeouts are calculated relative to the C<ev_now ()>
1765	time. This is usually the right thing as this timestamp refers to the time	1932	time. This is usually the right thing as this timestamp refers to the time
…		…
1836	C<repeat> value), or reset the running timer to the C<repeat> value.	2003	C<repeat> value), or reset the running timer to the C<repeat> value.
1837		2004
1838	This sounds a bit complicated, see L<Be smart about timeouts>, above, for a	2005	This sounds a bit complicated, see L<Be smart about timeouts>, above, for a
1839	usage example.	2006	usage example.
1840		2007
1841	=item ev_timer_remaining (loop, ev_timer *)	2008	=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
1842		2009
1843	Returns the remaining time until a timer fires. If the timer is active,	2010	Returns the remaining time until a timer fires. If the timer is active,
1844	then this time is relative to the current event loop time, otherwise it's	2011	then this time is relative to the current event loop time, otherwise it's
1845	the timeout value currently configured.	2012	the timeout value currently configured.
1846		2013
1847	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns	2014	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
1848	C<5>. When the timer is started and one second passes, C<ev_timer_remain>	2015	C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
1849	will return C<4>. When the timer expires and is restarted, it will return	2016	will return C<4>. When the timer expires and is restarted, it will return
1850	roughly C<7> (likely slightly less as callback invocation takes some time,	2017	roughly C<7> (likely slightly less as callback invocation takes some time,
1851	too), and so on.	2018	too), and so on.
1852		2019
1853	=item ev_tstamp repeat [read-write]	2020	=item ev_tstamp repeat [read-write]
…		…
1882	}	2049	}
1883		2050
1884	ev_timer mytimer;	2051	ev_timer mytimer;
1885	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2052	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1886	ev_timer_again (&mytimer); /* start timer */	2053	ev_timer_again (&mytimer); /* start timer */
1887	ev_loop (loop, 0);	2054	ev_run (loop, 0);
1888		2055
1889	// and in some piece of code that gets executed on any "activity":	2056	// and in some piece of code that gets executed on any "activity":
1890	// reset the timeout to start ticking again at 10 seconds	2057	// reset the timeout to start ticking again at 10 seconds
1891	ev_timer_again (&mytimer);	2058	ev_timer_again (&mytimer);
1892		2059
…		…
1918		2085
1919	As with timers, the callback is guaranteed to be invoked only when the	2086	As with timers, the callback is guaranteed to be invoked only when the
1920	point in time where it is supposed to trigger has passed. If multiple	2087	point in time where it is supposed to trigger has passed. If multiple
1921	timers become ready during the same loop iteration then the ones with	2088	timers become ready during the same loop iteration then the ones with
1922	earlier time-out values are invoked before ones with later time-out values	2089	earlier time-out values are invoked before ones with later time-out values
1923	(but this is no longer true when a callback calls C<ev_loop> recursively).	2090	(but this is no longer true when a callback calls C<ev_run> recursively).
1924		2091
1925	=head3 Watcher-Specific Functions and Data Members	2092	=head3 Watcher-Specific Functions and Data Members
1926		2093
1927	=over 4	2094	=over 4
1928		2095
…		…
2056	Example: Call a callback every hour, or, more precisely, whenever the	2223	Example: Call a callback every hour, or, more precisely, whenever the
2057	system time is divisible by 3600. The callback invocation times have	2224	system time is divisible by 3600. The callback invocation times have
2058	potentially a lot of jitter, but good long-term stability.	2225	potentially a lot of jitter, but good long-term stability.
2059		2226
2060	static void	2227	static void
2061	clock_cb (struct ev_loop loop, ev_io w, int revents)	2228	clock_cb (struct ev_loop loop, ev_periodic w, int revents)
2062	{	2229	{
2063	... its now a full hour (UTC, or TAI or whatever your clock follows)	2230	... its now a full hour (UTC, or TAI or whatever your clock follows)
2064	}	2231	}
2065		2232
2066	ev_periodic hourly_tick;	2233	ev_periodic hourly_tick;
…		…
2107		2274
2108	When the first watcher gets started will libev actually register something	2275	When the first watcher gets started will libev actually register something
2109	with the kernel (thus it coexists with your own signal handlers as long as	2276	with the kernel (thus it coexists with your own signal handlers as long as
2110	you don't register any with libev for the same signal).	2277	you don't register any with libev for the same signal).
2111		2278
2112	Both the signal mask state (C<sigprocmask>) and the signal handler state
2113	(C<sigaction>) are unspecified after starting a signal watcher (and after
2114	sotpping it again), that is, libev might or might not block the signal,
2115	and might or might not set or restore the installed signal handler.
2116
2117	If possible and supported, libev will install its handlers with	2279	If possible and supported, libev will install its handlers with
2118	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should	2280	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
2119	not be unduly interrupted. If you have a problem with system calls getting	2281	not be unduly interrupted. If you have a problem with system calls getting
2120	interrupted by signals you can block all signals in an C<ev_check> watcher	2282	interrupted by signals you can block all signals in an C<ev_check> watcher
2121	and unblock them in an C<ev_prepare> watcher.	2283	and unblock them in an C<ev_prepare> watcher.
2122		2284
		2285	=head3 The special problem of inheritance over fork/execve/pthread_create
		2286
		2287	Both the signal mask (C<sigprocmask>) and the signal disposition
		2288	(C<sigaction>) are unspecified after starting a signal watcher (and after
		2289	stopping it again), that is, libev might or might not block the signal,
		2290	and might or might not set or restore the installed signal handler.
		2291
		2292	While this does not matter for the signal disposition (libev never
		2293	sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on
		2294	C<execve>), this matters for the signal mask: many programs do not expect
		2295	certain signals to be blocked.
		2296
		2297	This means that before calling C<exec> (from the child) you should reset
		2298	the signal mask to whatever "default" you expect (all clear is a good
		2299	choice usually).
		2300
		2301	The simplest way to ensure that the signal mask is reset in the child is
		2302	to install a fork handler with C<pthread_atfork> that resets it. That will
		2303	catch fork calls done by libraries (such as the libc) as well.
		2304
		2305	In current versions of libev, the signal will not be blocked indefinitely
		2306	unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
		2307	the window of opportunity for problems, it will not go away, as libev
		2308	I<has> to modify the signal mask, at least temporarily.
		2309
		2310	So I can't stress this enough: I<If you do not reset your signal mask when
		2311	you expect it to be empty, you have a race condition in your code>. This
		2312	is not a libev-specific thing, this is true for most event libraries.
		2313
2123	=head3 Watcher-Specific Functions and Data Members	2314	=head3 Watcher-Specific Functions and Data Members
2124		2315
2125	=over 4	2316	=over 4
2126		2317
2127	=item ev_signal_init (ev_signal *, callback, int signum)	2318	=item ev_signal_init (ev_signal *, callback, int signum)
…		…
2142	Example: Try to exit cleanly on SIGINT.	2333	Example: Try to exit cleanly on SIGINT.
2143		2334
2144	static void	2335	static void
2145	sigint_cb (struct ev_loop loop, ev_signal w, int revents)	2336	sigint_cb (struct ev_loop loop, ev_signal w, int revents)
2146	{	2337	{
2147	ev_unloop (loop, EVUNLOOP_ALL);	2338	ev_break (loop, EVBREAK_ALL);
2148	}	2339	}
2149		2340
2150	ev_signal signal_watcher;	2341	ev_signal signal_watcher;
2151	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2342	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2152	ev_signal_start (loop, &signal_watcher);	2343	ev_signal_start (loop, &signal_watcher);
…		…
2538		2729
2539	Prepare and check watchers are usually (but not always) used in pairs:	2730	Prepare and check watchers are usually (but not always) used in pairs:
2540	prepare watchers get invoked before the process blocks and check watchers	2731	prepare watchers get invoked before the process blocks and check watchers
2541	afterwards.	2732	afterwards.
2542		2733
2543	You I<must not> call C<ev_loop> or similar functions that enter	2734	You I<must not> call C<ev_run> or similar functions that enter
2544	the current event loop from either C<ev_prepare> or C<ev_check>	2735	the current event loop from either C<ev_prepare> or C<ev_check>
2545	watchers. Other loops than the current one are fine, however. The	2736	watchers. Other loops than the current one are fine, however. The
2546	rationale behind this is that you do not need to check for recursion in	2737	rationale behind this is that you do not need to check for recursion in
2547	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2738	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2548	C<ev_check> so if you have one watcher of each kind they will always be	2739	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2716		2907
2717	if (timeout >= 0)	2908	if (timeout >= 0)
2718	// create/start timer	2909	// create/start timer
2719		2910
2720	// poll	2911	// poll
2721	ev_loop (EV_A_ 0);	2912	ev_run (EV_A_ 0);
2722		2913
2723	// stop timer again	2914	// stop timer again
2724	if (timeout >= 0)	2915	if (timeout >= 0)
2725	ev_timer_stop (EV_A_ &to);	2916	ev_timer_stop (EV_A_ &to);
2726		2917
…		…
2804	if you do not want that, you need to temporarily stop the embed watcher).	2995	if you do not want that, you need to temporarily stop the embed watcher).
2805		2996
2806	=item ev_embed_sweep (loop, ev_embed *)	2997	=item ev_embed_sweep (loop, ev_embed *)
2807		2998
2808	Make a single, non-blocking sweep over the embedded loop. This works	2999	Make a single, non-blocking sweep over the embedded loop. This works
2809	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	3000	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2810	appropriate way for embedded loops.	3001	appropriate way for embedded loops.
2811		3002
2812	=item struct ev_loop *other [read-only]	3003	=item struct ev_loop *other [read-only]
2813		3004
2814	The embedded event loop.	3005	The embedded event loop.
…		…
2874	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3065	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2875	handlers will be invoked, too, of course.	3066	handlers will be invoked, too, of course.
2876		3067
2877	=head3 The special problem of life after fork - how is it possible?	3068	=head3 The special problem of life after fork - how is it possible?
2878		3069
2879	Most uses of C<fork()> consist of forking, then some simple calls to ste	3070	Most uses of C<fork()> consist of forking, then some simple calls to set
2880	up/change the process environment, followed by a call to C<exec()>. This	3071	up/change the process environment, followed by a call to C<exec()>. This
2881	sequence should be handled by libev without any problems.	3072	sequence should be handled by libev without any problems.
2882		3073
2883	This changes when the application actually wants to do event handling	3074	This changes when the application actually wants to do event handling
2884	in the child, or both parent in child, in effect "continuing" after the	3075	in the child, or both parent in child, in effect "continuing" after the
…		…
2900	disadvantage of having to use multiple event loops (which do not support	3091	disadvantage of having to use multiple event loops (which do not support
2901	signal watchers).	3092	signal watchers).
2902		3093
2903	When this is not possible, or you want to use the default loop for	3094	When this is not possible, or you want to use the default loop for
2904	other reasons, then in the process that wants to start "fresh", call	3095	other reasons, then in the process that wants to start "fresh", call
2905	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3096	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2906	the default loop will "orphan" (not stop) all registered watchers, so you	3097	Destroying the default loop will "orphan" (not stop) all registered
2907	have to be careful not to execute code that modifies those watchers. Note	3098	watchers, so you have to be careful not to execute code that modifies
2908	also that in that case, you have to re-register any signal watchers.	3099	those watchers. Note also that in that case, you have to re-register any
		3100	signal watchers.
2909		3101
2910	=head3 Watcher-Specific Functions and Data Members	3102	=head3 Watcher-Specific Functions and Data Members
2911		3103
2912	=over 4	3104	=over 4
2913		3105
2914	=item ev_fork_init (ev_signal *, callback)	3106	=item ev_fork_init (ev_fork *, callback)
2915		3107
2916	Initialises and configures the fork watcher - it has no parameters of any	3108	Initialises and configures the fork watcher - it has no parameters of any
2917	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,	3109	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
2918	believe me.	3110	really.
2919		3111
2920	=back	3112	=back
2921		3113
2922		3114
		3115	=head2 C<ev_cleanup> - even the best things end
		3116
		3117	Cleanup watchers are called just before the event loop is being destroyed
		3118	by a call to C<ev_loop_destroy>.
		3119
		3120	While there is no guarantee that the event loop gets destroyed, cleanup
		3121	watchers provide a convenient method to install cleanup hooks for your
		3122	program, worker threads and so on - you just to make sure to destroy the
		3123	loop when you want them to be invoked.
		3124
		3125	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3126	all other watchers, they do not keep a reference to the event loop (which
		3127	makes a lot of sense if you think about it). Like all other watchers, you
		3128	can call libev functions in the callback, except C<ev_cleanup_start>.
		3129
		3130	=head3 Watcher-Specific Functions and Data Members
		3131
		3132	=over 4
		3133
		3134	=item ev_cleanup_init (ev_cleanup *, callback)
		3135
		3136	Initialises and configures the cleanup watcher - it has no parameters of
		3137	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3138	pointless, I assure you.
		3139
		3140	=back
		3141
		3142	Example: Register an atexit handler to destroy the default loop, so any
		3143	cleanup functions are called.
		3144
		3145	static void
		3146	program_exits (void)
		3147	{
		3148	ev_loop_destroy (EV_DEFAULT_UC);
		3149	}
		3150
		3151	...
		3152	atexit (program_exits);
		3153
		3154
2923	=head2 C<ev_async> - how to wake up another event loop	3155	=head2 C<ev_async> - how to wake up an event loop
2924		3156
2925	In general, you cannot use an C<ev_loop> from multiple threads or other	3157	In general, you cannot use an C<ev_run> from multiple threads or other
2926	asynchronous sources such as signal handlers (as opposed to multiple event	3158	asynchronous sources such as signal handlers (as opposed to multiple event
2927	loops - those are of course safe to use in different threads).	3159	loops - those are of course safe to use in different threads).
2928		3160
2929	Sometimes, however, you need to wake up another event loop you do not	3161	Sometimes, however, you need to wake up an event loop you do not control,
2930	control, for example because it belongs to another thread. This is what	3162	for example because it belongs to another thread. This is what C<ev_async>
2931	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3163	watchers do: as long as the C<ev_async> watcher is active, you can signal
2932	can signal it by calling C<ev_async_send>, which is thread- and signal	3164	it by calling C<ev_async_send>, which is thread- and signal safe.
2933	safe.
2934		3165
2935	This functionality is very similar to C<ev_signal> watchers, as signals,	3166	This functionality is very similar to C<ev_signal> watchers, as signals,
2936	too, are asynchronous in nature, and signals, too, will be compressed	3167	too, are asynchronous in nature, and signals, too, will be compressed
2937	(i.e. the number of callback invocations may be less than the number of	3168	(i.e. the number of callback invocations may be less than the number of
2938	C<ev_async_sent> calls).	3169	C<ev_async_sent> calls).
…		…
2943	=head3 Queueing	3174	=head3 Queueing
2944		3175
2945	C<ev_async> does not support queueing of data in any way. The reason	3176	C<ev_async> does not support queueing of data in any way. The reason
2946	is that the author does not know of a simple (or any) algorithm for a	3177	is that the author does not know of a simple (or any) algorithm for a
2947	multiple-writer-single-reader queue that works in all cases and doesn't	3178	multiple-writer-single-reader queue that works in all cases and doesn't
2948	need elaborate support such as pthreads.	3179	need elaborate support such as pthreads or unportable memory access
		3180	semantics.
2949		3181
2950	That means that if you want to queue data, you have to provide your own	3182	That means that if you want to queue data, you have to provide your own
2951	queue. But at least I can tell you how to implement locking around your	3183	queue. But at least I can tell you how to implement locking around your
2952	queue:	3184	queue:
2953		3185
…		…
3092		3324
3093	If C<timeout> is less than 0, then no timeout watcher will be	3325	If C<timeout> is less than 0, then no timeout watcher will be
3094	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3326	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
3095	repeat = 0) will be started. C<0> is a valid timeout.	3327	repeat = 0) will be started. C<0> is a valid timeout.
3096		3328
3097	The callback has the type C<void (cb)(int revents, void arg)> and gets	3329	The callback has the type C<void (cb)(int revents, void arg)> and is
3098	passed an C<revents> set like normal event callbacks (a combination of	3330	passed an C<revents> set like normal event callbacks (a combination of
3099	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3331	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
3100	value passed to C<ev_once>. Note that it is possible to receive I<both>	3332	value passed to C<ev_once>. Note that it is possible to receive I<both>
3101	a timeout and an io event at the same time - you probably should give io	3333	a timeout and an io event at the same time - you probably should give io
3102	events precedence.	3334	events precedence.
3103		3335
3104	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3336	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
3105		3337
3106	static void stdin_ready (int revents, void *arg)	3338	static void stdin_ready (int revents, void *arg)
3107	{	3339	{
3108	if (revents & EV_READ)	3340	if (revents & EV_READ)
3109	/* stdin might have data for us, joy! */;	3341	/* stdin might have data for us, joy! */;
3110	else if (revents & EV_TIMEOUT)	3342	else if (revents & EV_TIMER)
3111	/* doh, nothing entered */;	3343	/* doh, nothing entered */;
3112	}	3344	}
3113		3345
3114	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3346	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3115		3347
3116	=item ev_feed_event (struct ev_loop , watcher , int revents)
3117
3118	Feeds the given event set into the event loop, as if the specified event
3119	had happened for the specified watcher (which must be a pointer to an
3120	initialised but not necessarily started event watcher).
3121
3122	=item ev_feed_fd_event (struct ev_loop *, int fd, int revents)	3348	=item ev_feed_fd_event (loop, int fd, int revents)
3123		3349
3124	Feed an event on the given fd, as if a file descriptor backend detected	3350	Feed an event on the given fd, as if a file descriptor backend detected
3125	the given events it.	3351	the given events it.
3126		3352
3127	=item ev_feed_signal_event (struct ev_loop *loop, int signum)	3353	=item ev_feed_signal_event (loop, int signum)
3128		3354
3129	Feed an event as if the given signal occurred (C<loop> must be the default	3355	Feed an event as if the given signal occurred (C<loop> must be the default
3130	loop!).	3356	loop!).
3131		3357
3132	=back	3358	=back
…		…
3212		3438
3213	=over 4	3439	=over 4
3214		3440
3215	=item ev::TYPE::TYPE ()	3441	=item ev::TYPE::TYPE ()
3216		3442
3217	=item ev::TYPE::TYPE (struct ev_loop *)	3443	=item ev::TYPE::TYPE (loop)
3218		3444
3219	=item ev::TYPE::~TYPE	3445	=item ev::TYPE::~TYPE
3220		3446
3221	The constructor (optionally) takes an event loop to associate the watcher	3447	The constructor (optionally) takes an event loop to associate the watcher
3222	with. If it is omitted, it will use C<EV_DEFAULT>.	3448	with. If it is omitted, it will use C<EV_DEFAULT>.
…		…
3255	myclass obj;	3481	myclass obj;
3256	ev::io iow;	3482	ev::io iow;
3257	iow.set <myclass, &myclass::io_cb> (&obj);	3483	iow.set <myclass, &myclass::io_cb> (&obj);
3258		3484
3259	=item w->set (object *)	3485	=item w->set (object *)
3260
3261	This is an B<experimental> feature that might go away in a future version.
3262		3486
3263	This is a variation of a method callback - leaving out the method to call	3487	This is a variation of a method callback - leaving out the method to call
3264	will default the method to C<operator ()>, which makes it possible to use	3488	will default the method to C<operator ()>, which makes it possible to use
3265	functor objects without having to manually specify the C<operator ()> all	3489	functor objects without having to manually specify the C<operator ()> all
3266	the time. Incidentally, you can then also leave out the template argument	3490	the time. Incidentally, you can then also leave out the template argument
…		…
3299	Example: Use a plain function as callback.	3523	Example: Use a plain function as callback.
3300		3524
3301	static void io_cb (ev::io &w, int revents) { }	3525	static void io_cb (ev::io &w, int revents) { }
3302	iow.set <io_cb> ();	3526	iow.set <io_cb> ();
3303		3527
3304	=item w->set (struct ev_loop *)	3528	=item w->set (loop)
3305		3529
3306	Associates a different C<struct ev_loop> with this watcher. You can only	3530	Associates a different C<struct ev_loop> with this watcher. You can only
3307	do this when the watcher is inactive (and not pending either).	3531	do this when the watcher is inactive (and not pending either).
3308		3532
3309	=item w->set ([arguments])	3533	=item w->set ([arguments])
3310		3534
3311	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3535	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3312	called at least once. Unlike the C counterpart, an active watcher gets	3536	method or a suitable start method must be called at least once. Unlike the
3313	automatically stopped and restarted when reconfiguring it with this	3537	C counterpart, an active watcher gets automatically stopped and restarted
3314	method.	3538	when reconfiguring it with this method.
3315		3539
3316	=item w->start ()	3540	=item w->start ()
3317		3541
3318	Starts the watcher. Note that there is no C<loop> argument, as the	3542	Starts the watcher. Note that there is no C<loop> argument, as the
3319	constructor already stores the event loop.	3543	constructor already stores the event loop.
3320		3544
		3545	=item w->start ([arguments])
		3546
		3547	Instead of calling C<set> and C<start> methods separately, it is often
		3548	convenient to wrap them in one call. Uses the same type of arguments as
		3549	the configure C<set> method of the watcher.
		3550
3321	=item w->stop ()	3551	=item w->stop ()
3322		3552
3323	Stops the watcher if it is active. Again, no C<loop> argument.	3553	Stops the watcher if it is active. Again, no C<loop> argument.
3324		3554
3325	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3555	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3337		3567
3338	=back	3568	=back
3339		3569
3340	=back	3570	=back
3341		3571
3342	Example: Define a class with an IO and idle watcher, start one of them in	3572	Example: Define a class with two I/O and idle watchers, start the I/O
3343	the constructor.	3573	watchers in the constructor.
3344		3574
3345	class myclass	3575	class myclass
3346	{	3576	{
3347	ev::io io ; void io_cb (ev::io &w, int revents);	3577	ev::io io ; void io_cb (ev::io &w, int revents);
		3578	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3348	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3579	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3349		3580
3350	myclass (int fd)	3581	myclass (int fd)
3351	{	3582	{
3352	io .set <myclass, &myclass::io_cb > (this);	3583	io .set <myclass, &myclass::io_cb > (this);
		3584	io2 .set <myclass, &myclass::io2_cb > (this);
3353	idle.set <myclass, &myclass::idle_cb> (this);	3585	idle.set <myclass, &myclass::idle_cb> (this);
3354		3586
3355	io.start (fd, ev::READ);	3587	io.set (fd, ev::WRITE); // configure the watcher
		3588	io.start (); // start it whenever convenient
		3589
		3590	io2.start (fd, ev::READ); // set + start in one call
3356	}	3591	}
3357	};	3592	};
3358		3593
3359		3594
3360	=head1 OTHER LANGUAGE BINDINGS	3595	=head1 OTHER LANGUAGE BINDINGS
…		…
3406	=item Ocaml	3641	=item Ocaml
3407		3642
3408	Erkki Seppala has written Ocaml bindings for libev, to be found at	3643	Erkki Seppala has written Ocaml bindings for libev, to be found at
3409	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.	3644	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
3410		3645
		3646	=item Lua
		3647
		3648	Brian Maher has written a partial interface to libev for lua (at the
		3649	time of this writing, only C<ev_io> and C<ev_timer>), to be found at
		3650	L<http://github.com/brimworks/lua-ev>.
		3651
3411	=back	3652	=back
3412		3653
3413		3654
3414	=head1 MACRO MAGIC	3655	=head1 MACRO MAGIC
3415		3656
…		…
3428	loop argument"). The C<EV_A> form is used when this is the sole argument,	3669	loop argument"). The C<EV_A> form is used when this is the sole argument,
3429	C<EV_A_> is used when other arguments are following. Example:	3670	C<EV_A_> is used when other arguments are following. Example:
3430		3671
3431	ev_unref (EV_A);	3672	ev_unref (EV_A);
3432	ev_timer_add (EV_A_ watcher);	3673	ev_timer_add (EV_A_ watcher);
3433	ev_loop (EV_A_ 0);	3674	ev_run (EV_A_ 0);
3434		3675
3435	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3676	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3436	which is often provided by the following macro.	3677	which is often provided by the following macro.
3437		3678
3438	=item C<EV_P>, C<EV_P_>	3679	=item C<EV_P>, C<EV_P_>
…		…
3478	}	3719	}
3479		3720
3480	ev_check check;	3721	ev_check check;
3481	ev_check_init (&check, check_cb);	3722	ev_check_init (&check, check_cb);
3482	ev_check_start (EV_DEFAULT_ &check);	3723	ev_check_start (EV_DEFAULT_ &check);
3483	ev_loop (EV_DEFAULT_ 0);	3724	ev_run (EV_DEFAULT_ 0);
3484		3725
3485	=head1 EMBEDDING	3726	=head1 EMBEDDING
3486		3727
3487	Libev can (and often is) directly embedded into host	3728	Libev can (and often is) directly embedded into host
3488	applications. Examples of applications that embed it include the Deliantra	3729	applications. Examples of applications that embed it include the Deliantra
…		…
3568	libev.m4	3809	libev.m4
3569		3810
3570	=head2 PREPROCESSOR SYMBOLS/MACROS	3811	=head2 PREPROCESSOR SYMBOLS/MACROS
3571		3812
3572	Libev can be configured via a variety of preprocessor symbols you have to	3813	Libev can be configured via a variety of preprocessor symbols you have to
3573	define before including any of its files. The default in the absence of	3814	define before including (or compiling) any of its files. The default in
3574	autoconf is documented for every option.	3815	the absence of autoconf is documented for every option.
		3816
		3817	Symbols marked with "(h)" do not change the ABI, and can have different
		3818	values when compiling libev vs. including F<ev.h>, so it is permissible
		3819	to redefine them before including F<ev.h> without breaking compatibility
		3820	to a compiled library. All other symbols change the ABI, which means all
		3821	users of libev and the libev code itself must be compiled with compatible
		3822	settings.
3575		3823
3576	=over 4	3824	=over 4
3577		3825
		3826	=item EV_COMPAT3 (h)
		3827
		3828	Backwards compatibility is a major concern for libev. This is why this
		3829	release of libev comes with wrappers for the functions and symbols that
		3830	have been renamed between libev version 3 and 4.
		3831
		3832	You can disable these wrappers (to test compatibility with future
		3833	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3834	sources. This has the additional advantage that you can drop the C<struct>
		3835	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3836	typedef in that case.
		3837
		3838	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3839	and in some even more future version the compatibility code will be
		3840	removed completely.
		3841
3578	=item EV_STANDALONE	3842	=item EV_STANDALONE (h)
3579		3843
3580	Must always be C<1> if you do not use autoconf configuration, which	3844	Must always be C<1> if you do not use autoconf configuration, which
3581	keeps libev from including F<config.h>, and it also defines dummy	3845	keeps libev from including F<config.h>, and it also defines dummy
3582	implementations for some libevent functions (such as logging, which is not	3846	implementations for some libevent functions (such as logging, which is not
3583	supported). It will also not define any of the structs usually found in	3847	supported). It will also not define any of the structs usually found in
3584	F<event.h> that are not directly supported by the libev core alone.	3848	F<event.h> that are not directly supported by the libev core alone.
3585		3849
3586	In stanbdalone mode, libev will still try to automatically deduce the	3850	In standalone mode, libev will still try to automatically deduce the
3587	configuration, but has to be more conservative.	3851	configuration, but has to be more conservative.
3588		3852
3589	=item EV_USE_MONOTONIC	3853	=item EV_USE_MONOTONIC
3590		3854
3591	If defined to be C<1>, libev will try to detect the availability of the	3855	If defined to be C<1>, libev will try to detect the availability of the
…		…
3656	be used is the winsock select). This means that it will call	3920	be used is the winsock select). This means that it will call
3657	C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,	3921	C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,
3658	it is assumed that all these functions actually work on fds, even	3922	it is assumed that all these functions actually work on fds, even
3659	on win32. Should not be defined on non-win32 platforms.	3923	on win32. Should not be defined on non-win32 platforms.
3660		3924
3661	=item EV_FD_TO_WIN32_HANDLE	3925	=item EV_FD_TO_WIN32_HANDLE(fd)
3662		3926
3663	If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map	3927	If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map
3664	file descriptors to socket handles. When not defining this symbol (the	3928	file descriptors to socket handles. When not defining this symbol (the
3665	default), then libev will call C<_get_osfhandle>, which is usually	3929	default), then libev will call C<_get_osfhandle>, which is usually
3666	correct. In some cases, programs use their own file descriptor management,	3930	correct. In some cases, programs use their own file descriptor management,
3667	in which case they can provide this function to map fds to socket handles.	3931	in which case they can provide this function to map fds to socket handles.
		3932
		3933	=item EV_WIN32_HANDLE_TO_FD(handle)
		3934
		3935	If C<EV_SELECT_IS_WINSOCKET> then libev maps handles to file descriptors
		3936	using the standard C<_open_osfhandle> function. For programs implementing
		3937	their own fd to handle mapping, overwriting this function makes it easier
		3938	to do so. This can be done by defining this macro to an appropriate value.
		3939
		3940	=item EV_WIN32_CLOSE_FD(fd)
		3941
		3942	If programs implement their own fd to handle mapping on win32, then this
		3943	macro can be used to override the C<close> function, useful to unregister
		3944	file descriptors again. Note that the replacement function has to close
		3945	the underlying OS handle.
3668		3946
3669	=item EV_USE_POLL	3947	=item EV_USE_POLL
3670		3948
3671	If defined to be C<1>, libev will compile in support for the C<poll>(2)	3949	If defined to be C<1>, libev will compile in support for the C<poll>(2)
3672	backend. Otherwise it will be enabled on non-win32 platforms. It	3950	backend. Otherwise it will be enabled on non-win32 platforms. It
…		…
3719	as well as for signal and thread safety in C<ev_async> watchers.	3997	as well as for signal and thread safety in C<ev_async> watchers.
3720		3998
3721	In the absence of this define, libev will use C<sig_atomic_t volatile>	3999	In the absence of this define, libev will use C<sig_atomic_t volatile>
3722	(from F<signal.h>), which is usually good enough on most platforms.	4000	(from F<signal.h>), which is usually good enough on most platforms.
3723		4001
3724	=item EV_H	4002	=item EV_H (h)
3725		4003
3726	The name of the F<ev.h> header file used to include it. The default if	4004	The name of the F<ev.h> header file used to include it. The default if
3727	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be	4005	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
3728	used to virtually rename the F<ev.h> header file in case of conflicts.	4006	used to virtually rename the F<ev.h> header file in case of conflicts.
3729		4007
3730	=item EV_CONFIG_H	4008	=item EV_CONFIG_H (h)
3731		4009
3732	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	4010	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
3733	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	4011	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
3734	C<EV_H>, above.	4012	C<EV_H>, above.
3735		4013
3736	=item EV_EVENT_H	4014	=item EV_EVENT_H (h)
3737		4015
3738	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	4016	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
3739	of how the F<event.h> header can be found, the default is C<"event.h">.	4017	of how the F<event.h> header can be found, the default is C<"event.h">.
3740		4018
3741	=item EV_PROTOTYPES	4019	=item EV_PROTOTYPES (h)
3742		4020
3743	If defined to be C<0>, then F<ev.h> will not define any function	4021	If defined to be C<0>, then F<ev.h> will not define any function
3744	prototypes, but still define all the structs and other symbols. This is	4022	prototypes, but still define all the structs and other symbols. This is
3745	occasionally useful if you want to provide your own wrapper functions	4023	occasionally useful if you want to provide your own wrapper functions
3746	around libev functions.	4024	around libev functions.
…		…
3768	fine.	4046	fine.
3769		4047
3770	If your embedding application does not need any priorities, defining these	4048	If your embedding application does not need any priorities, defining these
3771	both to C<0> will save some memory and CPU.	4049	both to C<0> will save some memory and CPU.
3772		4050
3773	=item EV_PERIODIC_ENABLE	4051	=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
		4052	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
		4053	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3774		4054
3775	If undefined or defined to be C<1>, then periodic timers are supported. If	4055	If undefined or defined to be C<1> (and the platform supports it), then
3776	defined to be C<0>, then they are not. Disabling them saves a few kB of	4056	the respective watcher type is supported. If defined to be C<0>, then it
3777	code.	4057	is not. Disabling watcher types mainly saves code size.
3778		4058
3779	=item EV_IDLE_ENABLE	4059	=item EV_FEATURES
3780
3781	If undefined or defined to be C<1>, then idle watchers are supported. If
3782	defined to be C<0>, then they are not. Disabling them saves a few kB of
3783	code.
3784
3785	=item EV_EMBED_ENABLE
3786
3787	If undefined or defined to be C<1>, then embed watchers are supported. If
3788	defined to be C<0>, then they are not. Embed watchers rely on most other
3789	watcher types, which therefore must not be disabled.
3790
3791	=item EV_STAT_ENABLE
3792
3793	If undefined or defined to be C<1>, then stat watchers are supported. If
3794	defined to be C<0>, then they are not.
3795
3796	=item EV_FORK_ENABLE
3797
3798	If undefined or defined to be C<1>, then fork watchers are supported. If
3799	defined to be C<0>, then they are not.
3800
3801	=item EV_ASYNC_ENABLE
3802
3803	If undefined or defined to be C<1>, then async watchers are supported. If
3804	defined to be C<0>, then they are not.
3805
3806	=item EV_MINIMAL
3807		4060
3808	If you need to shave off some kilobytes of code at the expense of some	4061	If you need to shave off some kilobytes of code at the expense of some
3809	speed (but with the full API), define this symbol to C<1>. Currently this	4062	speed (but with the full API), you can define this symbol to request
3810	is used to override some inlining decisions, saves roughly 30% code size	4063	certain subsets of functionality. The default is to enable all features
3811	on amd64. It also selects a much smaller 2-heap for timer management over	4064	that can be enabled on the platform.
3812	the default 4-heap.
3813		4065
3814	You can save even more by disabling watcher types you do not need	4066	A typical way to use this symbol is to define it to C<0> (or to a bitset
3815	and setting C<EV_MAXPRI> == C<EV_MINPRI>. Also, disabling C<assert>	4067	with some broad features you want) and then selectively re-enable
3816	(C<-DNDEBUG>) will usually reduce code size a lot.	4068	additional parts you want, for example if you want everything minimal,
		4069	but multiple event loop support, async and child watchers and the poll
		4070	backend, use this:
3817		4071
3818	Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to	4072	#define EV_FEATURES 0
3819	provide a bare-bones event library. See C<ev.h> for details on what parts	4073	#define EV_MULTIPLICITY 1
3820	of the API are still available, and do not complain if this subset changes	4074	#define EV_USE_POLL 1
3821	over time.	4075	#define EV_CHILD_ENABLE 1
		4076	#define EV_ASYNC_ENABLE 1
		4077
		4078	The actual value is a bitset, it can be a combination of the following
		4079	values:
		4080
		4081	=over 4
		4082
		4083	=item C<1> - faster/larger code
		4084
		4085	Use larger code to speed up some operations.
		4086
		4087	Currently this is used to override some inlining decisions (enlarging the
		4088	code size by roughly 30% on amd64).
		4089
		4090	When optimising for size, use of compiler flags such as C<-Os> with
		4091	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
		4092	assertions.
		4093
		4094	=item C<2> - faster/larger data structures
		4095
		4096	Replaces the small 2-heap for timer management by a faster 4-heap, larger
		4097	hash table sizes and so on. This will usually further increase code size
		4098	and can additionally have an effect on the size of data structures at
		4099	runtime.
		4100
		4101	=item C<4> - full API configuration
		4102
		4103	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
		4104	enables multiplicity (C<EV_MULTIPLICITY>=1).
		4105
		4106	=item C<8> - full API
		4107
		4108	This enables a lot of the "lesser used" API functions. See C<ev.h> for
		4109	details on which parts of the API are still available without this
		4110	feature, and do not complain if this subset changes over time.
		4111
		4112	=item C<16> - enable all optional watcher types
		4113
		4114	Enables all optional watcher types. If you want to selectively enable
		4115	only some watcher types other than I/O and timers (e.g. prepare,
		4116	embed, async, child...) you can enable them manually by defining
		4117	C<EV_watchertype_ENABLE> to C<1> instead.
		4118
		4119	=item C<32> - enable all backends
		4120
		4121	This enables all backends - without this feature, you need to enable at
		4122	least one backend manually (C<EV_USE_SELECT> is a good choice).
		4123
		4124	=item C<64> - enable OS-specific "helper" APIs
		4125
		4126	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
		4127	default.
		4128
		4129	=back
		4130
		4131	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
		4132	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
		4133	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
		4134	watchers, timers and monotonic clock support.
		4135
		4136	With an intelligent-enough linker (gcc+binutils are intelligent enough
		4137	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
		4138	your program might be left out as well - a binary starting a timer and an
		4139	I/O watcher then might come out at only 5Kb.
		4140
		4141	=item EV_AVOID_STDIO
		4142
		4143	If this is set to C<1> at compiletime, then libev will avoid using stdio
		4144	functions (printf, scanf, perror etc.). This will increase the code size
		4145	somewhat, but if your program doesn't otherwise depend on stdio and your
		4146	libc allows it, this avoids linking in the stdio library which is quite
		4147	big.
		4148
		4149	Note that error messages might become less precise when this option is
		4150	enabled.
3822		4151
3823	=item EV_NSIG	4152	=item EV_NSIG
3824		4153
3825	The highest supported signal number, +1 (or, the number of	4154	The highest supported signal number, +1 (or, the number of
3826	signals): Normally, libev tries to deduce the maximum number of signals	4155	signals): Normally, libev tries to deduce the maximum number of signals
3827	automatically, but sometimes this fails, in which case it can be	4156	automatically, but sometimes this fails, in which case it can be
3828	specified. Also, using a lower number than detected (C<32> should be	4157	specified. Also, using a lower number than detected (C<32> should be
3829	good for about any system in existance) can save some memory, as libev	4158	good for about any system in existence) can save some memory, as libev
3830	statically allocates some 12-24 bytes per signal number.	4159	statically allocates some 12-24 bytes per signal number.
3831		4160
3832	=item EV_PID_HASHSIZE	4161	=item EV_PID_HASHSIZE
3833		4162
3834	C<ev_child> watchers use a small hash table to distribute workload by	4163	C<ev_child> watchers use a small hash table to distribute workload by
3835	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	4164	pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
3836	than enough. If you need to manage thousands of children you might want to	4165	usually more than enough. If you need to manage thousands of children you
3837	increase this value (I<must> be a power of two).	4166	might want to increase this value (I<must> be a power of two).
3838		4167
3839	=item EV_INOTIFY_HASHSIZE	4168	=item EV_INOTIFY_HASHSIZE
3840		4169
3841	C<ev_stat> watchers use a small hash table to distribute workload by	4170	C<ev_stat> watchers use a small hash table to distribute workload by
3842	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	4171	inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
3843	usually more than enough. If you need to manage thousands of C<ev_stat>	4172	disabled), usually more than enough. If you need to manage thousands of
3844	watchers you might want to increase this value (I<must> be a power of	4173	C<ev_stat> watchers you might want to increase this value (I<must> be a
3845	two).	4174	power of two).
3846		4175
3847	=item EV_USE_4HEAP	4176	=item EV_USE_4HEAP
3848		4177
3849	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4178	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3850	timer and periodics heaps, libev uses a 4-heap when this symbol is defined	4179	timer and periodics heaps, libev uses a 4-heap when this symbol is defined
3851	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably	4180	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
3852	faster performance with many (thousands) of watchers.	4181	faster performance with many (thousands) of watchers.
3853		4182
3854	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4183	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3855	(disabled).	4184	will be C<0>.
3856		4185
3857	=item EV_HEAP_CACHE_AT	4186	=item EV_HEAP_CACHE_AT
3858		4187
3859	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4188	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3860	timer and periodics heaps, libev can cache the timestamp (I<at>) within	4189	timer and periodics heaps, libev can cache the timestamp (I<at>) within
3861	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	4190	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3862	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	4191	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3863	but avoids random read accesses on heap changes. This improves performance	4192	but avoids random read accesses on heap changes. This improves performance
3864	noticeably with many (hundreds) of watchers.	4193	noticeably with many (hundreds) of watchers.
3865		4194
3866	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4195	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3867	(disabled).	4196	will be C<0>.
3868		4197
3869	=item EV_VERIFY	4198	=item EV_VERIFY
3870		4199
3871	Controls how much internal verification (see C<ev_loop_verify ()>) will	4200	Controls how much internal verification (see C<ev_verify ()>) will
3872	be done: If set to C<0>, no internal verification code will be compiled	4201	be done: If set to C<0>, no internal verification code will be compiled
3873	in. If set to C<1>, then verification code will be compiled in, but not	4202	in. If set to C<1>, then verification code will be compiled in, but not
3874	called. If set to C<2>, then the internal verification code will be	4203	called. If set to C<2>, then the internal verification code will be
3875	called once per loop, which can slow down libev. If set to C<3>, then the	4204	called once per loop, which can slow down libev. If set to C<3>, then the
3876	verification code will be called very frequently, which will slow down	4205	verification code will be called very frequently, which will slow down
3877	libev considerably.	4206	libev considerably.
3878		4207
3879	The default is C<1>, unless C<EV_MINIMAL> is set, in which case it will be	4208	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3880	C<0>.	4209	will be C<0>.
3881		4210
3882	=item EV_COMMON	4211	=item EV_COMMON
3883		4212
3884	By default, all watchers have a C<void *data> member. By redefining	4213	By default, all watchers have a C<void *data> member. By redefining
3885	this macro to a something else you can include more and other types of	4214	this macro to something else you can include more and other types of
3886	members. You have to define it each time you include one of the files,	4215	members. You have to define it each time you include one of the files,
3887	though, and it must be identical each time.	4216	though, and it must be identical each time.
3888		4217
3889	For example, the perl EV module uses something like this:	4218	For example, the perl EV module uses something like this:
3890		4219
…		…
3943	file.	4272	file.
3944		4273
3945	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4274	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
3946	that everybody includes and which overrides some configure choices:	4275	that everybody includes and which overrides some configure choices:
3947		4276
3948	#define EV_MINIMAL 1	4277	#define EV_FEATURES 8
3949	#define EV_USE_POLL 0	4278	#define EV_USE_SELECT 1
3950	#define EV_MULTIPLICITY 0
3951	#define EV_PERIODIC_ENABLE 0	4279	#define EV_PREPARE_ENABLE 1
		4280	#define EV_IDLE_ENABLE 1
3952	#define EV_STAT_ENABLE 0	4281	#define EV_SIGNAL_ENABLE 1
3953	#define EV_FORK_ENABLE 0	4282	#define EV_CHILD_ENABLE 1
		4283	#define EV_USE_STDEXCEPT 0
3954	#define EV_CONFIG_H <config.h>	4284	#define EV_CONFIG_H <config.h>
3955	#define EV_MINPRI 0
3956	#define EV_MAXPRI 0
3957		4285
3958	#include "ev++.h"	4286	#include "ev++.h"
3959		4287
3960	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4288	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3961		4289
…		…
4092	userdata *u = ev_userdata (EV_A);	4420	userdata *u = ev_userdata (EV_A);
4093	pthread_mutex_lock (&u->lock);	4421	pthread_mutex_lock (&u->lock);
4094	}	4422	}
4095		4423
4096	The event loop thread first acquires the mutex, and then jumps straight	4424	The event loop thread first acquires the mutex, and then jumps straight
4097	into C<ev_loop>:	4425	into C<ev_run>:
4098		4426
4099	void *	4427	void *
4100	l_run (void *thr_arg)	4428	l_run (void *thr_arg)
4101	{	4429	{
4102	struct ev_loop loop = (struct ev_loop )thr_arg;	4430	struct ev_loop loop = (struct ev_loop )thr_arg;
4103		4431
4104	l_acquire (EV_A);	4432	l_acquire (EV_A);
4105	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4433	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4106	ev_loop (EV_A_ 0);	4434	ev_run (EV_A_ 0);
4107	l_release (EV_A);	4435	l_release (EV_A);
4108		4436
4109	return 0;	4437	return 0;
4110	}	4438	}
4111		4439
…		…
4163		4491
4164	=head3 COROUTINES	4492	=head3 COROUTINES
4165		4493
4166	Libev is very accommodating to coroutines ("cooperative threads"):	4494	Libev is very accommodating to coroutines ("cooperative threads"):
4167	libev fully supports nesting calls to its functions from different	4495	libev fully supports nesting calls to its functions from different
4168	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4496	coroutines (e.g. you can call C<ev_run> on the same loop from two
4169	different coroutines, and switch freely between both coroutines running	4497	different coroutines, and switch freely between both coroutines running
4170	the loop, as long as you don't confuse yourself). The only exception is	4498	the loop, as long as you don't confuse yourself). The only exception is
4171	that you must not do this from C<ev_periodic> reschedule callbacks.	4499	that you must not do this from C<ev_periodic> reschedule callbacks.
4172		4500
4173	Care has been taken to ensure that libev does not keep local state inside	4501	Care has been taken to ensure that libev does not keep local state inside
4174	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4502	C<ev_run>, and other calls do not usually allow for coroutine switches as
4175	they do not call any callbacks.	4503	they do not call any callbacks.
4176		4504
4177	=head2 COMPILER WARNINGS	4505	=head2 COMPILER WARNINGS
4178		4506
4179	Depending on your compiler and compiler settings, you might get no or a	4507	Depending on your compiler and compiler settings, you might get no or a
…		…
4190	maintainable.	4518	maintainable.
4191		4519
4192	And of course, some compiler warnings are just plain stupid, or simply	4520	And of course, some compiler warnings are just plain stupid, or simply
4193	wrong (because they don't actually warn about the condition their message	4521	wrong (because they don't actually warn about the condition their message
4194	seems to warn about). For example, certain older gcc versions had some	4522	seems to warn about). For example, certain older gcc versions had some
4195	warnings that resulted an extreme number of false positives. These have	4523	warnings that resulted in an extreme number of false positives. These have
4196	been fixed, but some people still insist on making code warn-free with	4524	been fixed, but some people still insist on making code warn-free with
4197	such buggy versions.	4525	such buggy versions.
4198		4526
4199	While libev is written to generate as few warnings as possible,	4527	While libev is written to generate as few warnings as possible,
4200	"warn-free" code is not a goal, and it is recommended not to build libev	4528	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4236	I suggest using suppression lists.	4564	I suggest using suppression lists.
4237		4565
4238		4566
4239	=head1 PORTABILITY NOTES	4567	=head1 PORTABILITY NOTES
4240		4568
		4569	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4570
		4571	GNU/Linux is the only common platform that supports 64 bit file/large file
		4572	interfaces but I<disables> them by default.
		4573
		4574	That means that libev compiled in the default environment doesn't support
		4575	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4576
		4577	Unfortunately, many programs try to work around this GNU/Linux issue
		4578	by enabling the large file API, which makes them incompatible with the
		4579	standard libev compiled for their system.
		4580
		4581	Likewise, libev cannot enable the large file API itself as this would
		4582	suddenly make it incompatible to the default compile time environment,
		4583	i.e. all programs not using special compile switches.
		4584
		4585	=head2 OS/X AND DARWIN BUGS
		4586
		4587	The whole thing is a bug if you ask me - basically any system interface
		4588	you touch is broken, whether it is locales, poll, kqueue or even the
		4589	OpenGL drivers.
		4590
		4591	=head3 C<kqueue> is buggy
		4592
		4593	The kqueue syscall is broken in all known versions - most versions support
		4594	only sockets, many support pipes.
		4595
		4596	Libev tries to work around this by not using C<kqueue> by default on this
		4597	rotten platform, but of course you can still ask for it when creating a
		4598	loop - embedding a socket-only kqueue loop into a select-based one is
		4599	probably going to work well.
		4600
		4601	=head3 C<poll> is buggy
		4602
		4603	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4604	implementation by something calling C<kqueue> internally around the 10.5.6
		4605	release, so now C<kqueue> I<and> C<poll> are broken.
		4606
		4607	Libev tries to work around this by not using C<poll> by default on
		4608	this rotten platform, but of course you can still ask for it when creating
		4609	a loop.
		4610
		4611	=head3 C<select> is buggy
		4612
		4613	All that's left is C<select>, and of course Apple found a way to fuck this
		4614	one up as well: On OS/X, C<select> actively limits the number of file
		4615	descriptors you can pass in to 1024 - your program suddenly crashes when
		4616	you use more.
		4617
		4618	There is an undocumented "workaround" for this - defining
		4619	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4620	work on OS/X.
		4621
		4622	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4623
		4624	=head3 C<errno> reentrancy
		4625
		4626	The default compile environment on Solaris is unfortunately so
		4627	thread-unsafe that you can't even use components/libraries compiled
		4628	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4629	defined by default. A valid, if stupid, implementation choice.
		4630
		4631	If you want to use libev in threaded environments you have to make sure
		4632	it's compiled with C<_REENTRANT> defined.
		4633
		4634	=head3 Event port backend
		4635
		4636	The scalable event interface for Solaris is called "event
		4637	ports". Unfortunately, this mechanism is very buggy in all major
		4638	releases. If you run into high CPU usage, your program freezes or you get
		4639	a large number of spurious wakeups, make sure you have all the relevant
		4640	and latest kernel patches applied. No, I don't know which ones, but there
		4641	are multiple ones to apply, and afterwards, event ports actually work
		4642	great.
		4643
		4644	If you can't get it to work, you can try running the program by setting
		4645	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4646	C<select> backends.
		4647
		4648	=head2 AIX POLL BUG
		4649
		4650	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4651	this by trying to avoid the poll backend altogether (i.e. it's not even
		4652	compiled in), which normally isn't a big problem as C<select> works fine
		4653	with large bitsets on AIX, and AIX is dead anyway.
		4654
4241	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4655	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4656
		4657	=head3 General issues
4242		4658
4243	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4659	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4244	requires, and its I/O model is fundamentally incompatible with the POSIX	4660	requires, and its I/O model is fundamentally incompatible with the POSIX
4245	model. Libev still offers limited functionality on this platform in	4661	model. Libev still offers limited functionality on this platform in
4246	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4662	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4247	descriptors. This only applies when using Win32 natively, not when using	4663	descriptors. This only applies when using Win32 natively, not when using
4248	e.g. cygwin.	4664	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4665	as every compielr comes with a slightly differently broken/incompatible
		4666	environment.
4249		4667
4250	Lifting these limitations would basically require the full	4668	Lifting these limitations would basically require the full
4251	re-implementation of the I/O system. If you are into these kinds of	4669	re-implementation of the I/O system. If you are into this kind of thing,
4252	things, then note that glib does exactly that for you in a very portable	4670	then note that glib does exactly that for you in a very portable way (note
4253	way (note also that glib is the slowest event library known to man).	4671	also that glib is the slowest event library known to man).
4254		4672
4255	There is no supported compilation method available on windows except	4673	There is no supported compilation method available on windows except
4256	embedding it into other applications.	4674	embedding it into other applications.
4257		4675
4258	Sensible signal handling is officially unsupported by Microsoft - libev	4676	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4286	you do I<not> compile the F<ev.c> or any other embedded source files!):	4704	you do I<not> compile the F<ev.c> or any other embedded source files!):
4287		4705
4288	#include "evwrap.h"	4706	#include "evwrap.h"
4289	#include "ev.c"	4707	#include "ev.c"
4290		4708
4291	=over 4
4292
4293	=item The winsocket select function	4709	=head3 The winsocket C<select> function
4294		4710
4295	The winsocket C<select> function doesn't follow POSIX in that it	4711	The winsocket C<select> function doesn't follow POSIX in that it
4296	requires socket I<handles> and not socket I<file descriptors> (it is	4712	requires socket I<handles> and not socket I<file descriptors> (it is
4297	also extremely buggy). This makes select very inefficient, and also	4713	also extremely buggy). This makes select very inefficient, and also
4298	requires a mapping from file descriptors to socket handles (the Microsoft	4714	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4307	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4723	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4308		4724
4309	Note that winsockets handling of fd sets is O(n), so you can easily get a	4725	Note that winsockets handling of fd sets is O(n), so you can easily get a
4310	complexity in the O(n²) range when using win32.	4726	complexity in the O(n²) range when using win32.
4311		4727
4312	=item Limited number of file descriptors	4728	=head3 Limited number of file descriptors
4313		4729
4314	Windows has numerous arbitrary (and low) limits on things.	4730	Windows has numerous arbitrary (and low) limits on things.
4315		4731
4316	Early versions of winsocket's select only supported waiting for a maximum	4732	Early versions of winsocket's select only supported waiting for a maximum
4317	of C<64> handles (probably owning to the fact that all windows kernels	4733	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4332	runtime libraries. This might get you to about C<512> or C<2048> sockets	4748	runtime libraries. This might get you to about C<512> or C<2048> sockets
4333	(depending on windows version and/or the phase of the moon). To get more,	4749	(depending on windows version and/or the phase of the moon). To get more,
4334	you need to wrap all I/O functions and provide your own fd management, but	4750	you need to wrap all I/O functions and provide your own fd management, but
4335	the cost of calling select (O(n²)) will likely make this unworkable.	4751	the cost of calling select (O(n²)) will likely make this unworkable.
4336		4752
4337	=back
4338
4339	=head2 PORTABILITY REQUIREMENTS	4753	=head2 PORTABILITY REQUIREMENTS
4340		4754
4341	In addition to a working ISO-C implementation and of course the	4755	In addition to a working ISO-C implementation and of course the
4342	backend-specific APIs, libev relies on a few additional extensions:	4756	backend-specific APIs, libev relies on a few additional extensions:
4343		4757
…		…
4349	Libev assumes not only that all watcher pointers have the same internal	4763	Libev assumes not only that all watcher pointers have the same internal
4350	structure (guaranteed by POSIX but not by ISO C for example), but it also	4764	structure (guaranteed by POSIX but not by ISO C for example), but it also
4351	assumes that the same (machine) code can be used to call any watcher	4765	assumes that the same (machine) code can be used to call any watcher
4352	callback: The watcher callbacks have different type signatures, but libev	4766	callback: The watcher callbacks have different type signatures, but libev
4353	calls them using an C<ev_watcher *> internally.	4767	calls them using an C<ev_watcher *> internally.
		4768
		4769	=item pointer accesses must be thread-atomic
		4770
		4771	Accessing a pointer value must be atomic, it must both be readable and
		4772	writable in one piece - this is the case on all current architectures.
4354		4773
4355	=item C<sig_atomic_t volatile> must be thread-atomic as well	4774	=item C<sig_atomic_t volatile> must be thread-atomic as well
4356		4775
4357	The type C<sig_atomic_t volatile> (or whatever is defined as	4776	The type C<sig_atomic_t volatile> (or whatever is defined as
4358	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different	4777	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
…		…
4381	watchers.	4800	watchers.
4382		4801
4383	=item C<double> must hold a time value in seconds with enough accuracy	4802	=item C<double> must hold a time value in seconds with enough accuracy
4384		4803
4385	The type C<double> is used to represent timestamps. It is required to	4804	The type C<double> is used to represent timestamps. It is required to
4386	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4805	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4387	enough for at least into the year 4000. This requirement is fulfilled by	4806	good enough for at least into the year 4000 with millisecond accuracy
		4807	(the design goal for libev). This requirement is overfulfilled by
4388	implementations implementing IEEE 754, which is basically all existing	4808	implementations using IEEE 754, which is basically all existing ones. With
4389	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4809	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4390	2200.
4391		4810
4392	=back	4811	=back
4393		4812
4394	If you know of other additional requirements drop me a note.	4813	If you know of other additional requirements drop me a note.
4395		4814
…		…
4463	involves iterating over all running async watchers or all signal numbers.	4882	involves iterating over all running async watchers or all signal numbers.
4464		4883
4465	=back	4884	=back
4466		4885
4467		4886
		4887	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4888
		4889	The major version 4 introduced some incompatible changes to the API.
		4890
		4891	At the moment, the C<ev.h> header file provides compatibility definitions
		4892	for all changes, so most programs should still compile. The compatibility
		4893	layer might be removed in later versions of libev, so better update to the
		4894	new API early than late.
		4895
		4896	=over 4
		4897
		4898	=item C<EV_COMPAT3> backwards compatibility mechanism
		4899
		4900	The backward compatibility mechanism can be controlled by
		4901	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4902	section.
		4903
		4904	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4905
		4906	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4907
		4908	ev_loop_destroy (EV_DEFAULT_UC);
		4909	ev_loop_fork (EV_DEFAULT);
		4910
		4911	=item function/symbol renames
		4912
		4913	A number of functions and symbols have been renamed:
		4914
		4915	ev_loop => ev_run
		4916	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4917	EVLOOP_ONESHOT => EVRUN_ONCE
		4918
		4919	ev_unloop => ev_break
		4920	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4921	EVUNLOOP_ONE => EVBREAK_ONE
		4922	EVUNLOOP_ALL => EVBREAK_ALL
		4923
		4924	EV_TIMEOUT => EV_TIMER
		4925
		4926	ev_loop_count => ev_iteration
		4927	ev_loop_depth => ev_depth
		4928	ev_loop_verify => ev_verify
		4929
		4930	Most functions working on C<struct ev_loop> objects don't have an
		4931	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4932	associated constants have been renamed to not collide with the C<struct
		4933	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4934	as all other watcher types. Note that C<ev_loop_fork> is still called
		4935	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4936	typedef.
		4937
		4938	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4939
		4940	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4941	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4942	and work, but the library code will of course be larger.
		4943
		4944	=back
		4945
		4946
4468	=head1 GLOSSARY	4947	=head1 GLOSSARY
4469		4948
4470	=over 4	4949	=over 4
4471		4950
4472	=item active	4951	=item active
4473		4952
4474	A watcher is active as long as it has been started (has been attached to	4953	A watcher is active as long as it has been started and not yet stopped.
4475	an event loop) but not yet stopped (disassociated from the event loop).	4954	See L<WATCHER STATES> for details.
4476		4955
4477	=item application	4956	=item application
4478		4957
4479	In this document, an application is whatever is using libev.	4958	In this document, an application is whatever is using libev.
		4959
		4960	=item backend
		4961
		4962	The part of the code dealing with the operating system interfaces.
4480		4963
4481	=item callback	4964	=item callback
4482		4965
4483	The address of a function that is called when some event has been	4966	The address of a function that is called when some event has been
4484	detected. Callbacks are being passed the event loop, the watcher that	4967	detected. Callbacks are being passed the event loop, the watcher that
4485	received the event, and the actual event bitset.	4968	received the event, and the actual event bitset.
4486		4969
4487	=item callback invocation	4970	=item callback/watcher invocation
4488		4971
4489	The act of calling the callback associated with a watcher.	4972	The act of calling the callback associated with a watcher.
4490		4973
4491	=item event	4974	=item event
4492		4975
4493	A change of state of some external event, such as data now being available	4976	A change of state of some external event, such as data now being available
4494	for reading on a file descriptor, time having passed or simply not having	4977	for reading on a file descriptor, time having passed or simply not having
4495	any other events happening anymore.	4978	any other events happening anymore.
4496		4979
4497	In libev, events are represented as single bits (such as C<EV_READ> or	4980	In libev, events are represented as single bits (such as C<EV_READ> or
4498	C<EV_TIMEOUT>).	4981	C<EV_TIMER>).
4499		4982
4500	=item event library	4983	=item event library
4501		4984
4502	A software package implementing an event model and loop.	4985	A software package implementing an event model and loop.
4503		4986
…		…
4511	The model used to describe how an event loop handles and processes	4994	The model used to describe how an event loop handles and processes
4512	watchers and events.	4995	watchers and events.
4513		4996
4514	=item pending	4997	=item pending
4515		4998
4516	A watcher is pending as soon as the corresponding event has been detected,	4999	A watcher is pending as soon as the corresponding event has been
4517	and stops being pending as soon as the watcher will be invoked or its	5000	detected. See L<WATCHER STATES> for details.
4518	pending status is explicitly cleared by the application.
4519
4520	A watcher can be pending, but not active. Stopping a watcher also clears
4521	its pending status.
4522		5001
4523	=item real time	5002	=item real time
4524		5003
4525	The physical time that is observed. It is apparently strictly monotonic :)	5004	The physical time that is observed. It is apparently strictly monotonic :)
4526		5005
…		…
4533	=item watcher	5012	=item watcher
4534		5013
4535	A data structure that describes interest in certain events. Watchers need	5014	A data structure that describes interest in certain events. Watchers need
4536	to be started (attached to an event loop) before they can receive events.	5015	to be started (attached to an event loop) before they can receive events.
4537		5016
4538	=item watcher invocation
4539
4540	The act of calling the callback associated with a watcher.
4541
4542	=back	5017	=back
4543		5018
4544	=head1 AUTHOR	5019	=head1 AUTHOR
4545		5020
4546	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5021	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
		5022	Magnusson and Emanuele Giaquinta.
4547		5023

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Comparing libev/ev.pod (file contents): Revision 1.260 by root, Sun Jul 19 21:18:03 2009 UTC vs. Revision 1.335 by root, Mon Oct 25 10:32:05 2010 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.260 by root, Sun Jul 19 21:18:03 2009 UTC vs.
Revision 1.335 by root, Mon Oct 25 10:32:05 2010 UTC