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Revision 1.323 by root, Sun Oct 24 18:01:26 2010 UTC

…		…
26	puts ("stdin ready");	26	puts ("stdin ready");
27	// for one-shot events, one must manually stop the watcher	27	// for one-shot events, one must manually stop the watcher
28	// with its corresponding stop function.	28	// with its corresponding stop function.
29	ev_io_stop (EV_A_ w);	29	ev_io_stop (EV_A_ w);
30		30
31	// this causes all nested ev_loop's to stop iterating	31	// this causes all nested ev_run's to stop iterating
32	ev_unloop (EV_A_ EVUNLOOP_ALL);	32	ev_break (EV_A_ EVBREAK_ALL);
33	}	33	}
34		34
35	// another callback, this time for a time-out	35	// another callback, this time for a time-out
36	static void	36	static void
37	timeout_cb (EV_P_ ev_timer *w, int revents)	37	timeout_cb (EV_P_ ev_timer *w, int revents)
38	{	38	{
39	puts ("timeout");	39	puts ("timeout");
40	// this causes the innermost ev_loop to stop iterating	40	// this causes the innermost ev_run to stop iterating
41	ev_unloop (EV_A_ EVUNLOOP_ONE);	41	ev_break (EV_A_ EVBREAK_ONE);
42	}	42	}
43		43
44	int	44	int
45	main (void)	45	main (void)
46	{	46	{
47	// use the default event loop unless you have special needs	47	// use the default event loop unless you have special needs
48	struct ev_loop *loop = ev_default_loop (0);	48	struct ev_loop *loop = EV_DEFAULT;
49		49
50	// initialise an io watcher, then start it	50	// initialise an io watcher, then start it
51	// this one will watch for stdin to become readable	51	// this one will watch for stdin to become readable
52	ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);	52	ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
53	ev_io_start (loop, &stdin_watcher);	53	ev_io_start (loop, &stdin_watcher);
…		…
56	// simple non-repeating 5.5 second timeout	56	// simple non-repeating 5.5 second timeout
57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
58	ev_timer_start (loop, &timeout_watcher);	58	ev_timer_start (loop, &timeout_watcher);
59		59
60	// now wait for events to arrive	60	// now wait for events to arrive
61	ev_loop (loop, 0);	61	ev_run (loop, 0);
62		62
63	// unloop was called, so exit	63	// unloop was called, so exit
64	return 0;	64	return 0;
65	}	65	}
66		66
…		…
75	While this document tries to be as complete as possible in documenting	75	While this document tries to be as complete as possible in documenting
76	libev, its usage and the rationale behind its design, it is not a tutorial	76	libev, its usage and the rationale behind its design, it is not a tutorial
77	on event-based programming, nor will it introduce event-based programming	77	on event-based programming, nor will it introduce event-based programming
78	with libev.	78	with libev.
79		79
80	Familarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
82		82
83	=head1 ABOUT LIBEV	83	=head1 ABOUT LIBEV
84		84
85	Libev is an event loop: you register interest in certain events (such as a	85	Libev is an event loop: you register interest in certain events (such as a
…		…
98	=head2 FEATURES	98	=head2 FEATURES
99		99
100	Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the	100	Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the
101	BSD-specific C<kqueue> and the Solaris-specific event port mechanisms	101	BSD-specific C<kqueue> and the Solaris-specific event port mechanisms
102	for file descriptor events (C<ev_io>), the Linux C<inotify> interface	102	for file descriptor events (C<ev_io>), the Linux C<inotify> interface
103	(for C<ev_stat>), relative timers (C<ev_timer>), absolute timers	103	(for C<ev_stat>), Linux eventfd/signalfd (for faster and cleaner
104	with customised rescheduling (C<ev_periodic>), synchronous signals	104	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	105	timers (C<ev_timer>), absolute timers with customised rescheduling
106	watchers dealing with the event loop mechanism itself (C<ev_idle>,	106	(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	107	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	108	loop mechanism itself (C<ev_idle>, C<ev_embed>, C<ev_prepare> and
109	(C<ev_fork>).	109	C<ev_check> watchers) as well as file watchers (C<ev_stat>) and even
		110	limited support for fork events (C<ev_fork>).
110		111
111	It also is quite fast (see this	112	It also is quite fast (see this
112	L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent	113	L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent
113	for example).	114	for example).
114		115
…		…
117	Libev is very configurable. In this manual the default (and most common)	118	Libev is very configurable. In this manual the default (and most common)
118	configuration will be described, which supports multiple event loops. For	119	configuration will be described, which supports multiple event loops. For
119	more info about various configuration options please have a look at	120	more info about various configuration options please have a look at
120	B<EMBED> section in this manual. If libev was configured without support	121	B<EMBED> section in this manual. If libev was configured without support
121	for multiple event loops, then all functions taking an initial argument of	122	for multiple event loops, then all functions taking an initial argument of
122	name C<loop> (which is always of type C<ev_loop *>) will not have	123	name C<loop> (which is always of type C<struct ev_loop *>) will not have
123	this argument.	124	this argument.
124		125
125	=head2 TIME REPRESENTATION	126	=head2 TIME REPRESENTATION
126		127
127	Libev represents time as a single floating point number, representing	128	Libev represents time as a single floating point number, representing
128	the (fractional) number of seconds since the (POSIX) epoch (somewhere	129	the (fractional) number of seconds since the (POSIX) epoch (in practice
129	near the beginning of 1970, details are complicated, don't ask). This	130	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	131	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	132	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	133	any calculations on it, you should treat it as some floating point value.
		134
133	component C<stamp> might indicate, it is also used for time differences	135	Unlike the name component C<stamp> might indicate, it is also used for
134	throughout libev.	136	time differences (e.g. delays) throughout libev.
135		137
136	=head1 ERROR HANDLING	138	=head1 ERROR HANDLING
137		139
138	Libev knows three classes of errors: operating system errors, usage errors	140	Libev knows three classes of errors: operating system errors, usage errors
139	and internal errors (bugs).	141	and internal errors (bugs).
…		…
163		165
164	=item ev_tstamp ev_time ()	166	=item ev_tstamp ev_time ()
165		167
166	Returns the current time as libev would use it. Please note that the	168	Returns the current time as libev would use it. Please note that the
167	C<ev_now> function is usually faster and also often returns the timestamp	169	C<ev_now> function is usually faster and also often returns the timestamp
168	you actually want to know.	170	you actually want to know. Also interesting is the combination of
		171	C<ev_update_now> and C<ev_now>.
169		172
170	=item ev_sleep (ev_tstamp interval)	173	=item ev_sleep (ev_tstamp interval)
171		174
172	Sleep for the given interval: The current thread will be blocked until	175	Sleep for the given interval: The current thread will be blocked until
173	either it is interrupted or the given time interval has passed. Basically	176	either it is interrupted or the given time interval has passed. Basically
…		…
190	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
191	compatible to older versions, so a larger minor version alone is usually	194	compatible to older versions, so a larger minor version alone is usually
192	not a problem.	195	not a problem.
193		196
194	Example: Make sure we haven't accidentally been linked against the wrong	197	Example: Make sure we haven't accidentally been linked against the wrong
195	version.	198	version (note, however, that this will not detect other ABI mismatches,
		199	such as LFS or reentrancy).
196		200
197	assert (("libev version mismatch",	201	assert (("libev version mismatch",
198	ev_version_major () == EV_VERSION_MAJOR	202	ev_version_major () == EV_VERSION_MAJOR
199	&& ev_version_minor () >= EV_VERSION_MINOR));	203	&& ev_version_minor () >= EV_VERSION_MINOR));
200		204
…		…
211	assert (("sorry, no epoll, no sex",	215	assert (("sorry, no epoll, no sex",
212	ev_supported_backends () & EVBACKEND_EPOLL));	216	ev_supported_backends () & EVBACKEND_EPOLL));
213		217
214	=item unsigned int ev_recommended_backends ()	218	=item unsigned int ev_recommended_backends ()
215		219
216	Return the set of all backends compiled into this binary of libev and also	220	Return the set of all backends compiled into this binary of libev and
217	recommended for this platform. This set is often smaller than the one	221	also recommended for this platform, meaning it will work for most file
		222	descriptor types. This set is often smaller than the one returned by
218	returned by C<ev_supported_backends>, as for example kqueue is broken on	223	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
219	most BSDs and will not be auto-detected unless you explicitly request it	224	and will not be auto-detected unless you explicitly request it (assuming
220	(assuming you know what you are doing). This is the set of backends that	225	you know what you are doing). This is the set of backends that libev will
221	libev will probe for if you specify no backends explicitly.	226	probe for if you specify no backends explicitly.
222		227
223	=item unsigned int ev_embeddable_backends ()	228	=item unsigned int ev_embeddable_backends ()
224		229
225	Returns the set of backends that are embeddable in other event loops. This	230	Returns the set of backends that are embeddable in other event loops. This
226	is the theoretical, all-platform, value. To find which backends	231	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	232	current system. To find which embeddable backends might be supported on
228	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	233	the current system, you would need to look at C<ev_embeddable_backends ()
229	recommended ones.	234	& ev_supported_backends ()>, likewise for recommended ones.
230		235
231	See the description of C<ev_embed> watchers for more info.	236	See the description of C<ev_embed> watchers for more info.
232		237
233	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]	238	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]
234		239
…		…
288	...	293	...
289	ev_set_syserr_cb (fatal_error);	294	ev_set_syserr_cb (fatal_error);
290		295
291	=back	296	=back
292		297
293	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	298	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
294		299
295	An event loop is described by a C<struct ev_loop *> (the C<struct>	300	An event loop is described by a C<struct ev_loop *> (the C<struct> is
296	is I<not> optional in this case, as there is also an C<ev_loop>	301	I<not> optional in this case unless libev 3 compatibility is disabled, as
297	I<function>).	302	libev 3 had an C<ev_loop> function colliding with the struct name).
298		303
299	The library knows two types of such loops, the I<default> loop, which	304	The library knows two types of such loops, the I<default> loop, which
300	supports signals and child events, and dynamically created loops which do	305	supports signals and child events, and dynamically created event loops
301	not.	306	which do not.
302		307
303	=over 4	308	=over 4
304		309
305	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
306		311
307	This will initialise the default event loop if it hasn't been initialised	312	This returns the "default" event loop object, which is what you should
308	yet and return it. If the default loop could not be initialised, returns	313	normally use when you just need "the event loop". Event loop objects and
309	false. If it already was initialised it simply returns it (and ignores the	314	the C<flags> parameter are described in more detail in the entry for
310	flags. If that is troubling you, check C<ev_backend ()> afterwards).	315	C<ev_loop_new>.
		316
		317	If the default loop is already initialised then this function simply
		318	returns it (and ignores the flags. If that is troubling you, check
		319	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		320	flags, which should almost always be C<0>, unless the caller is also the
		321	one calling C<ev_run> or otherwise qualifies as "the main program".
311		322
312	If you don't know what event loop to use, use the one returned from this	323	If you don't know what event loop to use, use the one returned from this
313	function.	324	function (or via the C<EV_DEFAULT> macro).
314		325
315	Note that this function is I<not> thread-safe, so if you want to use it	326	Note that this function is I<not> thread-safe, so if you want to use it
316	from multiple threads, you have to lock (note also that this is unlikely,	327	from multiple threads, you have to employ some kind of mutex (note also
317	as loops cannot be shared easily between threads anyway).	328	that this case is unlikely, as loops cannot be shared easily between
		329	threads anyway).
318		330
319	The default loop is the only loop that can handle C<ev_signal> and	331	The default loop is the only loop that can handle C<ev_child> watchers,
320	C<ev_child> watchers, and to do this, it always registers a handler	332	and to do this, it always registers a handler for C<SIGCHLD>. If this is
321	for C<SIGCHLD>. If this is a problem for your application you can either	333	a problem for your application you can either create a dynamic loop with
322	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	334	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
323	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	335	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
324	C<ev_default_init>.	336
		337	Example: This is the most typical usage.
		338
		339	if (!ev_default_loop (0))
		340	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		341
		342	Example: Restrict libev to the select and poll backends, and do not allow
		343	environment settings to be taken into account:
		344
		345	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
		346
		347	=item struct ev_loop *ev_loop_new (unsigned int flags)
		348
		349	This will create and initialise a new event loop object. If the loop
		350	could not be initialised, returns false.
		351
		352	Note that this function I<is> thread-safe, and one common way to use
		353	libev with threads is indeed to create one loop per thread, and using the
		354	default loop in the "main" or "initial" thread.
325		355
326	The flags argument can be used to specify special behaviour or specific	356	The flags argument can be used to specify special behaviour or specific
327	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	357	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
328		358
329	The following flags are supported:	359	The following flags are supported:
…		…
344	useful to try out specific backends to test their performance, or to work	374	useful to try out specific backends to test their performance, or to work
345	around bugs.	375	around bugs.
346		376
347	=item C<EVFLAG_FORKCHECK>	377	=item C<EVFLAG_FORKCHECK>
348		378
349	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	379	Instead of calling C<ev_loop_fork> manually after a fork, you can also
350	a fork, you can also make libev check for a fork in each iteration by	380	make libev check for a fork in each iteration by enabling this flag.
351	enabling this flag.
352		381
353	This works by calling C<getpid ()> on every iteration of the loop,	382	This works by calling C<getpid ()> on every iteration of the loop,
354	and thus this might slow down your event loop if you do a lot of loop	383	and thus this might slow down your event loop if you do a lot of loop
355	iterations and little real work, but is usually not noticeable (on my	384	iterations and little real work, but is usually not noticeable (on my
356	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	385	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
…		…
362	flag.	391	flag.
363		392
364	This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS>	393	This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS>
365	environment variable.	394	environment variable.
366		395
		396	=item C<EVFLAG_NOINOTIFY>
		397
		398	When this flag is specified, then libev will not attempt to use the
		399	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and
		400	testing, this flag can be useful to conserve inotify file descriptors, as
		401	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
		402
		403	=item C<EVFLAG_SIGNALFD>
		404
		405	When this flag is specified, then libev will attempt to use the
		406	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API
		407	delivers signals synchronously, which makes it both faster and might make
		408	it possible to get the queued signal data. It can also simplify signal
		409	handling with threads, as long as you properly block signals in your
		410	threads that are not interested in handling them.
		411
		412	Signalfd will not be used by default as this changes your signal mask, and
		413	there are a lot of shoddy libraries and programs (glib's threadpool for
		414	example) that can't properly initialise their signal masks.
		415
367	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	416	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
368		417
369	This is your standard select(2) backend. Not I<completely> standard, as	418	This is your standard select(2) backend. Not I<completely> standard, as
370	libev tries to roll its own fd_set with no limits on the number of fds,	419	libev tries to roll its own fd_set with no limits on the number of fds,
371	but if that fails, expect a fairly low limit on the number of fds when	420	but if that fails, expect a fairly low limit on the number of fds when
…		…
394		443
395	This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and	444	This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and
396	C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>.	445	C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>.
397		446
398	=item C<EVBACKEND_EPOLL> (value 4, Linux)	447	=item C<EVBACKEND_EPOLL> (value 4, Linux)
		448
		449	Use the linux-specific epoll(7) interface (for both pre- and post-2.6.9
		450	kernels).
399		451
400	For few fds, this backend is a bit little slower than poll and select,	452	For few fds, this backend is a bit little slower than poll and select,
401	but it scales phenomenally better. While poll and select usually scale	453	but it scales phenomenally better. While poll and select usually scale
402	like O(total_fds) where n is the total number of fds (or the highest fd),	454	like O(total_fds) where n is the total number of fds (or the highest fd),
403	epoll scales either O(1) or O(active_fds).	455	epoll scales either O(1) or O(active_fds).
…		…
415	of course I<doesn't>, and epoll just loves to report events for totally	467	of course I<doesn't>, and epoll just loves to report events for totally
416	I<different> file descriptors (even already closed ones, so one cannot	468	I<different> file descriptors (even already closed ones, so one cannot
417	even remove them from the set) than registered in the set (especially	469	even remove them from the set) than registered in the set (especially
418	on SMP systems). Libev tries to counter these spurious notifications by	470	on SMP systems). Libev tries to counter these spurious notifications by
419	employing an additional generation counter and comparing that against the	471	employing an additional generation counter and comparing that against the
420	events to filter out spurious ones, recreating the set when required.	472	events to filter out spurious ones, recreating the set when required. Last
		473	not least, it also refuses to work with some file descriptors which work
		474	perfectly fine with C<select> (files, many character devices...).
421		475
422	While stopping, setting and starting an I/O watcher in the same iteration	476	While stopping, setting and starting an I/O watcher in the same iteration
423	will result in some caching, there is still a system call per such	477	will result in some caching, there is still a system call per such
424	incident (because the same I<file descriptor> could point to a different	478	incident (because the same I<file descriptor> could point to a different
425	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	479	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
518		572
519	It is definitely not recommended to use this flag.	573	It is definitely not recommended to use this flag.
520		574
521	=back	575	=back
522		576
523	If one or more of these are or'ed into the flags value, then only these	577	If one or more of the backend flags are or'ed into the flags value,
524	backends will be tried (in the reverse order as listed here). If none are	578	then only these backends will be tried (in the reverse order as listed
525	specified, all backends in C<ev_recommended_backends ()> will be tried.	579	here). If none are specified, all backends in C<ev_recommended_backends
526		580	()> will be tried.
527	Example: This is the most typical usage.
528
529	if (!ev_default_loop (0))
530	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
531
532	Example: Restrict libev to the select and poll backends, and do not allow
533	environment settings to be taken into account:
534
535	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
536
537	Example: Use whatever libev has to offer, but make sure that kqueue is
538	used if available (warning, breaks stuff, best use only with your own
539	private event loop and only if you know the OS supports your types of
540	fds):
541
542	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
543
544	=item struct ev_loop *ev_loop_new (unsigned int flags)
545
546	Similar to C<ev_default_loop>, but always creates a new event loop that is
547	always distinct from the default loop. Unlike the default loop, it cannot
548	handle signal and child watchers, and attempts to do so will be greeted by
549	undefined behaviour (or a failed assertion if assertions are enabled).
550
551	Note that this function I<is> thread-safe, and the recommended way to use
552	libev with threads is indeed to create one loop per thread, and using the
553	default loop in the "main" or "initial" thread.
554		581
555	Example: Try to create a event loop that uses epoll and nothing else.	582	Example: Try to create a event loop that uses epoll and nothing else.
556		583
557	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
558	if (!epoller)	585	if (!epoller)
559	fatal ("no epoll found here, maybe it hides under your chair");	586	fatal ("no epoll found here, maybe it hides under your chair");
560		587
		588	Example: Use whatever libev has to offer, but make sure that kqueue is
		589	used if available.
		590
		591	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
		592
561	=item ev_default_destroy ()	593	=item ev_loop_destroy (loop)
562		594
563	Destroys the default loop again (frees all memory and kernel state	595	Destroys an event loop object (frees all memory and kernel state
564	etc.). None of the active event watchers will be stopped in the normal	596	etc.). None of the active event watchers will be stopped in the normal
565	sense, so e.g. C<ev_is_active> might still return true. It is your	597	sense, so e.g. C<ev_is_active> might still return true. It is your
566	responsibility to either stop all watchers cleanly yourself I<before>	598	responsibility to either stop all watchers cleanly yourself I<before>
567	calling this function, or cope with the fact afterwards (which is usually	599	calling this function, or cope with the fact afterwards (which is usually
568	the easiest thing, you can just ignore the watchers and/or C<free ()> them	600	the easiest thing, you can just ignore the watchers and/or C<free ()> them
…		…
570		602
571	Note that certain global state, such as signal state (and installed signal	603	Note that certain global state, such as signal state (and installed signal
572	handlers), will not be freed by this function, and related watchers (such	604	handlers), will not be freed by this function, and related watchers (such
573	as signal and child watchers) would need to be stopped manually.	605	as signal and child watchers) would need to be stopped manually.
574		606
575	In general it is not advisable to call this function except in the	607	This function is normally used on loop objects allocated by
576	rare occasion where you really need to free e.g. the signal handling	608	C<ev_loop_new>, but it can also be used on the default loop returned by
		609	C<ev_default_loop>, in which case it is not thread-safe.
		610
		611	Note that it is not advisable to call this function on the default loop
		612	except in the rare occasion where you really need to free it's resources.
577	pipe fds. If you need dynamically allocated loops it is better to use	613	If you need dynamically allocated loops it is better to use C<ev_loop_new>
578	C<ev_loop_new> and C<ev_loop_destroy>).	614	and C<ev_loop_destroy>.
579		615
580	=item ev_loop_destroy (loop)	616	=item ev_loop_fork (loop)
581		617
582	Like C<ev_default_destroy>, but destroys an event loop created by an
583	earlier call to C<ev_loop_new>.
584
585	=item ev_default_fork ()
586
587	This function sets a flag that causes subsequent C<ev_loop> iterations	618	This function sets a flag that causes subsequent C<ev_run> iterations to
588	to reinitialise the kernel state for backends that have one. Despite the	619	reinitialise the kernel state for backends that have one. Despite the
589	name, you can call it anytime, but it makes most sense after forking, in	620	name, you can call it anytime, but it makes most sense after forking, in
590	the child process (or both child and parent, but that again makes little	621	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
591	sense). You I<must> call it in the child before using any of the libev	622	child before resuming or calling C<ev_run>.
592	functions, and it will only take effect at the next C<ev_loop> iteration.	623
		624	Again, you I<have> to call it on I<any> loop that you want to re-use after
		625	a fork, I<even if you do not plan to use the loop in the parent>. This is
		626	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
		627	during fork.
593		628
594	On the other hand, you only need to call this function in the child	629	On the other hand, you only need to call this function in the child
595	process if and only if you want to use the event library in the child. If	630	process if and only if you want to use the event loop in the child. If
596	you just fork+exec, you don't have to call it at all.	631	you just fork+exec or create a new loop in the child, you don't have to
		632	call it at all (in fact, C<epoll> is so badly broken that it makes a
		633	difference, but libev will usually detect this case on its own and do a
		634	costly reset of the backend).
597		635
598	The function itself is quite fast and it's usually not a problem to call	636	The function itself is quite fast and it's usually not a problem to call
599	it just in case after a fork. To make this easy, the function will fit in	637	it just in case after a fork.
600	quite nicely into a call to C<pthread_atfork>:
601		638
		639	Example: Automate calling C<ev_loop_fork> on the default loop when
		640	using pthreads.
		641
		642	static void
		643	post_fork_child (void)
		644	{
		645	ev_loop_fork (EV_DEFAULT);
		646	}
		647
		648	...
602	pthread_atfork (0, 0, ev_default_fork);	649	pthread_atfork (0, 0, post_fork_child);
603
604	=item ev_loop_fork (loop)
605
606	Like C<ev_default_fork>, but acts on an event loop created by
607	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
608	after fork that you want to re-use in the child, and how you do this is
609	entirely your own problem.
610		650
611	=item int ev_is_default_loop (loop)	651	=item int ev_is_default_loop (loop)
612		652
613	Returns true when the given loop is, in fact, the default loop, and false	653	Returns true when the given loop is, in fact, the default loop, and false
614	otherwise.	654	otherwise.
615		655
616	=item unsigned int ev_loop_count (loop)	656	=item unsigned int ev_iteration (loop)
617		657
618	Returns the count of loop iterations for the loop, which is identical to	658	Returns the current iteration count for the event loop, which is identical
619	the number of times libev did poll for new events. It starts at C<0> and	659	to the number of times libev did poll for new events. It starts at C<0>
620	happily wraps around with enough iterations.	660	and happily wraps around with enough iterations.
621		661
622	This value can sometimes be useful as a generation counter of sorts (it	662	This value can sometimes be useful as a generation counter of sorts (it
623	"ticks" the number of loop iterations), as it roughly corresponds with	663	"ticks" the number of loop iterations), as it roughly corresponds with
624	C<ev_prepare> and C<ev_check> calls.	664	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		665	prepare and check phases.
		666
		667	=item unsigned int ev_depth (loop)
		668
		669	Returns the number of times C<ev_run> was entered minus the number of
		670	times C<ev_run> was exited, in other words, the recursion depth.
		671
		672	Outside C<ev_run>, this number is zero. In a callback, this number is
		673	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
		674	in which case it is higher.
		675
		676	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
		677	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		678	ungentleman-like behaviour unless it's really convenient.
625		679
626	=item unsigned int ev_backend (loop)	680	=item unsigned int ev_backend (loop)
627		681
628	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	682	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
629	use.	683	use.
…		…
638		692
639	=item ev_now_update (loop)	693	=item ev_now_update (loop)
640		694
641	Establishes the current time by querying the kernel, updating the time	695	Establishes the current time by querying the kernel, updating the time
642	returned by C<ev_now ()> in the progress. This is a costly operation and	696	returned by C<ev_now ()> in the progress. This is a costly operation and
643	is usually done automatically within C<ev_loop ()>.	697	is usually done automatically within C<ev_run ()>.
644		698
645	This function is rarely useful, but when some event callback runs for a	699	This function is rarely useful, but when some event callback runs for a
646	very long time without entering the event loop, updating libev's idea of	700	very long time without entering the event loop, updating libev's idea of
647	the current time is a good idea.	701	the current time is a good idea.
648		702
…		…
650		704
651	=item ev_suspend (loop)	705	=item ev_suspend (loop)
652		706
653	=item ev_resume (loop)	707	=item ev_resume (loop)
654		708
655	These two functions suspend and resume a loop, for use when the loop is	709	These two functions suspend and resume an event loop, for use when the
656	not used for a while and timeouts should not be processed.	710	loop is not used for a while and timeouts should not be processed.
657		711
658	A typical use case would be an interactive program such as a game: When	712	A typical use case would be an interactive program such as a game: When
659	the user presses C<^Z> to suspend the game and resumes it an hour later it	713	the user presses C<^Z> to suspend the game and resumes it an hour later it
660	would be best to handle timeouts as if no time had actually passed while	714	would be best to handle timeouts as if no time had actually passed while
661	the program was suspended. This can be achieved by calling C<ev_suspend>	715	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
663	C<ev_resume> directly afterwards to resume timer processing.	717	C<ev_resume> directly afterwards to resume timer processing.
664		718
665	Effectively, all C<ev_timer> watchers will be delayed by the time spend	719	Effectively, all C<ev_timer> watchers will be delayed by the time spend
666	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	720	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
667	will be rescheduled (that is, they will lose any events that would have	721	will be rescheduled (that is, they will lose any events that would have
668	occured while suspended).	722	occurred while suspended).
669		723
670	After calling C<ev_suspend> you B<must not> call I<any> function on the	724	After calling C<ev_suspend> you B<must not> call I<any> function on the
671	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	725	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
672	without a previous call to C<ev_suspend>.	726	without a previous call to C<ev_suspend>.
673		727
674	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	728	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
675	event loop time (see C<ev_now_update>).	729	event loop time (see C<ev_now_update>).
676		730
677	=item ev_loop (loop, int flags)	731	=item ev_run (loop, int flags)
678		732
679	Finally, this is it, the event handler. This function usually is called	733	Finally, this is it, the event handler. This function usually is called
680	after you initialised all your watchers and you want to start handling	734	after you have initialised all your watchers and you want to start
681	events.	735	handling events. It will ask the operating system for any new events, call
		736	the watcher callbacks, an then repeat the whole process indefinitely: This
		737	is why event loops are called I<loops>.
682		738
683	If the flags argument is specified as C<0>, it will not return until	739	If the flags argument is specified as C<0>, it will keep handling events
684	either no event watchers are active anymore or C<ev_unloop> was called.	740	until either no event watchers are active anymore or C<ev_break> was
		741	called.
685		742
686	Please note that an explicit C<ev_unloop> is usually better than	743	Please note that an explicit C<ev_break> is usually better than
687	relying on all watchers to be stopped when deciding when a program has	744	relying on all watchers to be stopped when deciding when a program has
688	finished (especially in interactive programs), but having a program	745	finished (especially in interactive programs), but having a program
689	that automatically loops as long as it has to and no longer by virtue	746	that automatically loops as long as it has to and no longer by virtue
690	of relying on its watchers stopping correctly, that is truly a thing of	747	of relying on its watchers stopping correctly, that is truly a thing of
691	beauty.	748	beauty.
692		749
693	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	750	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
694	those events and any already outstanding ones, but will not block your	751	those events and any already outstanding ones, but will not wait and
695	process in case there are no events and will return after one iteration of	752	block your process in case there are no events and will return after one
696	the loop.	753	iteration of the loop. This is sometimes useful to poll and handle new
		754	events while doing lengthy calculations, to keep the program responsive.
697		755
698	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	756	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
699	necessary) and will handle those and any already outstanding ones. It	757	necessary) and will handle those and any already outstanding ones. It
700	will block your process until at least one new event arrives (which could	758	will block your process until at least one new event arrives (which could
701	be an event internal to libev itself, so there is no guarantee that a	759	be an event internal to libev itself, so there is no guarantee that a
702	user-registered callback will be called), and will return after one	760	user-registered callback will be called), and will return after one
703	iteration of the loop.	761	iteration of the loop.
704		762
705	This is useful if you are waiting for some external event in conjunction	763	This is useful if you are waiting for some external event in conjunction
706	with something not expressible using other libev watchers (i.e. "roll your	764	with something not expressible using other libev watchers (i.e. "roll your
707	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	765	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
708	usually a better approach for this kind of thing.	766	usually a better approach for this kind of thing.
709		767
710	Here are the gory details of what C<ev_loop> does:	768	Here are the gory details of what C<ev_run> does:
711		769
		770	- Increment loop depth.
		771	- Reset the ev_break status.
712	- Before the first iteration, call any pending watchers.	772	- Before the first iteration, call any pending watchers.
		773	LOOP:
713	* If EVFLAG_FORKCHECK was used, check for a fork.	774	- If EVFLAG_FORKCHECK was used, check for a fork.
714	- If a fork was detected (by any means), queue and call all fork watchers.	775	- If a fork was detected (by any means), queue and call all fork watchers.
715	- Queue and call all prepare watchers.	776	- Queue and call all prepare watchers.
		777	- If ev_break was called, goto FINISH.
716	- If we have been forked, detach and recreate the kernel state	778	- If we have been forked, detach and recreate the kernel state
717	as to not disturb the other process.	779	as to not disturb the other process.
718	- Update the kernel state with all outstanding changes.	780	- Update the kernel state with all outstanding changes.
719	- Update the "event loop time" (ev_now ()).	781	- Update the "event loop time" (ev_now ()).
720	- Calculate for how long to sleep or block, if at all	782	- Calculate for how long to sleep or block, if at all
721	(active idle watchers, EVLOOP_NONBLOCK or not having	783	(active idle watchers, EVRUN_NOWAIT or not having
722	any active watchers at all will result in not sleeping).	784	any active watchers at all will result in not sleeping).
723	- Sleep if the I/O and timer collect interval say so.	785	- Sleep if the I/O and timer collect interval say so.
		786	- Increment loop iteration counter.
724	- Block the process, waiting for any events.	787	- Block the process, waiting for any events.
725	- Queue all outstanding I/O (fd) events.	788	- Queue all outstanding I/O (fd) events.
726	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	789	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
727	- Queue all expired timers.	790	- Queue all expired timers.
728	- Queue all expired periodics.	791	- Queue all expired periodics.
729	- Unless any events are pending now, queue all idle watchers.	792	- Queue all idle watchers with priority higher than that of pending events.
730	- Queue all check watchers.	793	- Queue all check watchers.
731	- Call all queued watchers in reverse order (i.e. check watchers first).	794	- Call all queued watchers in reverse order (i.e. check watchers first).
732	Signals and child watchers are implemented as I/O watchers, and will	795	Signals and child watchers are implemented as I/O watchers, and will
733	be handled here by queueing them when their watcher gets executed.	796	be handled here by queueing them when their watcher gets executed.
734	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	797	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
735	were used, or there are no active watchers, return, otherwise	798	were used, or there are no active watchers, goto FINISH, otherwise
736	continue with step *.	799	continue with step LOOP.
		800	FINISH:
		801	- Reset the ev_break status iff it was EVBREAK_ONE.
		802	- Decrement the loop depth.
		803	- Return.
737		804
738	Example: Queue some jobs and then loop until no events are outstanding	805	Example: Queue some jobs and then loop until no events are outstanding
739	anymore.	806	anymore.
740		807
741	... queue jobs here, make sure they register event watchers as long	808	... queue jobs here, make sure they register event watchers as long
742	... as they still have work to do (even an idle watcher will do..)	809	... as they still have work to do (even an idle watcher will do..)
743	ev_loop (my_loop, 0);	810	ev_run (my_loop, 0);
744	... jobs done or somebody called unloop. yeah!	811	... jobs done or somebody called unloop. yeah!
745		812
746	=item ev_unloop (loop, how)	813	=item ev_break (loop, how)
747		814
748	Can be used to make a call to C<ev_loop> return early (but only after it	815	Can be used to make a call to C<ev_run> return early (but only after it
749	has processed all outstanding events). The C<how> argument must be either	816	has processed all outstanding events). The C<how> argument must be either
750	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	817	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
751	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	818	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
752		819
753	This "unloop state" will be cleared when entering C<ev_loop> again.	820	This "unloop state" will be cleared when entering C<ev_run> again.
754		821
755	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	822	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
756		823
757	=item ev_ref (loop)	824	=item ev_ref (loop)
758		825
759	=item ev_unref (loop)	826	=item ev_unref (loop)
760		827
761	Ref/unref can be used to add or remove a reference count on the event	828	Ref/unref can be used to add or remove a reference count on the event
762	loop: Every watcher keeps one reference, and as long as the reference	829	loop: Every watcher keeps one reference, and as long as the reference
763	count is nonzero, C<ev_loop> will not return on its own.	830	count is nonzero, C<ev_run> will not return on its own.
764		831
765	If you have a watcher you never unregister that should not keep C<ev_loop>	832	This is useful when you have a watcher that you never intend to
766	from returning, call ev_unref() after starting, and ev_ref() before	833	unregister, but that nevertheless should not keep C<ev_run> from
		834	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
767	stopping it.	835	before stopping it.
768		836
769	As an example, libev itself uses this for its internal signal pipe: It	837	As an example, libev itself uses this for its internal signal pipe: It
770	is not visible to the libev user and should not keep C<ev_loop> from	838	is not visible to the libev user and should not keep C<ev_run> from
771	exiting if no event watchers registered by it are active. It is also an	839	exiting if no event watchers registered by it are active. It is also an
772	excellent way to do this for generic recurring timers or from within	840	excellent way to do this for generic recurring timers or from within
773	third-party libraries. Just remember to I<unref after start> and I<ref	841	third-party libraries. Just remember to I<unref after start> and I<ref
774	before stop> (but only if the watcher wasn't active before, or was active	842	before stop> (but only if the watcher wasn't active before, or was active
775	before, respectively. Note also that libev might stop watchers itself	843	before, respectively. Note also that libev might stop watchers itself
776	(e.g. non-repeating timers) in which case you have to C<ev_ref>	844	(e.g. non-repeating timers) in which case you have to C<ev_ref>
777	in the callback).	845	in the callback).
778		846
779	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	847	Example: Create a signal watcher, but keep it from keeping C<ev_run>
780	running when nothing else is active.	848	running when nothing else is active.
781		849
782	ev_signal exitsig;	850	ev_signal exitsig;
783	ev_signal_init (&exitsig, sig_cb, SIGINT);	851	ev_signal_init (&exitsig, sig_cb, SIGINT);
784	ev_signal_start (loop, &exitsig);	852	ev_signal_start (loop, &exitsig);
…		…
829	usually doesn't make much sense to set it to a lower value than C<0.01>,	897	usually doesn't make much sense to set it to a lower value than C<0.01>,
830	as this approaches the timing granularity of most systems. Note that if	898	as this approaches the timing granularity of most systems. Note that if
831	you do transactions with the outside world and you can't increase the	899	you do transactions with the outside world and you can't increase the
832	parallelity, then this setting will limit your transaction rate (if you	900	parallelity, then this setting will limit your transaction rate (if you
833	need to poll once per transaction and the I/O collect interval is 0.01,	901	need to poll once per transaction and the I/O collect interval is 0.01,
834	then you can't do more than 100 transations per second).	902	then you can't do more than 100 transactions per second).
835		903
836	Setting the I<timeout collect interval> can improve the opportunity for	904	Setting the I<timeout collect interval> can improve the opportunity for
837	saving power, as the program will "bundle" timer callback invocations that	905	saving power, as the program will "bundle" timer callback invocations that
838	are "near" in time together, by delaying some, thus reducing the number of	906	are "near" in time together, by delaying some, thus reducing the number of
839	times the process sleeps and wakes up again. Another useful technique to	907	times the process sleeps and wakes up again. Another useful technique to
…		…
844	more often than 100 times per second:	912	more often than 100 times per second:
845		913
846	ev_set_timeout_collect_interval (EV_DEFAULT_UC_ 0.1);	914	ev_set_timeout_collect_interval (EV_DEFAULT_UC_ 0.1);
847	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	915	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
848		916
		917	=item ev_invoke_pending (loop)
		918
		919	This call will simply invoke all pending watchers while resetting their
		920	pending state. Normally, C<ev_run> does this automatically when required,
		921	but when overriding the invoke callback this call comes handy. This
		922	function can be invoked from a watcher - this can be useful for example
		923	when you want to do some lengthy calculation and want to pass further
		924	event handling to another thread (you still have to make sure only one
		925	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
		926
		927	=item int ev_pending_count (loop)
		928
		929	Returns the number of pending watchers - zero indicates that no watchers
		930	are pending.
		931
		932	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
		933
		934	This overrides the invoke pending functionality of the loop: Instead of
		935	invoking all pending watchers when there are any, C<ev_run> will call
		936	this callback instead. This is useful, for example, when you want to
		937	invoke the actual watchers inside another context (another thread etc.).
		938
		939	If you want to reset the callback, use C<ev_invoke_pending> as new
		940	callback.
		941
		942	=item ev_set_loop_release_cb (loop, void (*release)(EV_P), void (*acquire)(EV_P))
		943
		944	Sometimes you want to share the same loop between multiple threads. This
		945	can be done relatively simply by putting mutex_lock/unlock calls around
		946	each call to a libev function.
		947
		948	However, C<ev_run> can run an indefinite time, so it is not feasible
		949	to wait for it to return. One way around this is to wake up the event
		950	loop via C<ev_break> and C<av_async_send>, another way is to set these
		951	I<release> and I<acquire> callbacks on the loop.
		952
		953	When set, then C<release> will be called just before the thread is
		954	suspended waiting for new events, and C<acquire> is called just
		955	afterwards.
		956
		957	Ideally, C<release> will just call your mutex_unlock function, and
		958	C<acquire> will just call the mutex_lock function again.
		959
		960	While event loop modifications are allowed between invocations of
		961	C<release> and C<acquire> (that's their only purpose after all), no
		962	modifications done will affect the event loop, i.e. adding watchers will
		963	have no effect on the set of file descriptors being watched, or the time
		964	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
		965	to take note of any changes you made.
		966
		967	In theory, threads executing C<ev_run> will be async-cancel safe between
		968	invocations of C<release> and C<acquire>.
		969
		970	See also the locking example in the C<THREADS> section later in this
		971	document.
		972
		973	=item ev_set_userdata (loop, void *data)
		974
		975	=item ev_userdata (loop)
		976
		977	Set and retrieve a single C<void *> associated with a loop. When
		978	C<ev_set_userdata> has never been called, then C<ev_userdata> returns
		979	C<0.>
		980
		981	These two functions can be used to associate arbitrary data with a loop,
		982	and are intended solely for the C<invoke_pending_cb>, C<release> and
		983	C<acquire> callbacks described above, but of course can be (ab-)used for
		984	any other purpose as well.
		985
849	=item ev_loop_verify (loop)	986	=item ev_verify (loop)
850		987
851	This function only does something when C<EV_VERIFY> support has been	988	This function only does something when C<EV_VERIFY> support has been
852	compiled in, which is the default for non-minimal builds. It tries to go	989	compiled in, which is the default for non-minimal builds. It tries to go
853	through all internal structures and checks them for validity. If anything	990	through all internal structures and checks them for validity. If anything
854	is found to be inconsistent, it will print an error message to standard	991	is found to be inconsistent, it will print an error message to standard
…		…
865		1002
866	In the following description, uppercase C<TYPE> in names stands for the	1003	In the following description, uppercase C<TYPE> in names stands for the
867	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1004	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
868	watchers and C<ev_io_start> for I/O watchers.	1005	watchers and C<ev_io_start> for I/O watchers.
869		1006
870	A watcher is a structure that you create and register to record your	1007	A watcher is an opaque structure that you allocate and register to record
871	interest in some event. For instance, if you want to wait for STDIN to	1008	your interest in some event. To make a concrete example, imagine you want
872	become readable, you would create an C<ev_io> watcher for that:	1009	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1010	for that:
873		1011
874	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1012	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
875	{	1013	{
876	ev_io_stop (w);	1014	ev_io_stop (w);
877	ev_unloop (loop, EVUNLOOP_ALL);	1015	ev_break (loop, EVBREAK_ALL);
878	}	1016	}
879		1017
880	struct ev_loop *loop = ev_default_loop (0);	1018	struct ev_loop *loop = ev_default_loop (0);
881		1019
882	ev_io stdin_watcher;	1020	ev_io stdin_watcher;
883		1021
884	ev_init (&stdin_watcher, my_cb);	1022	ev_init (&stdin_watcher, my_cb);
885	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1023	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
886	ev_io_start (loop, &stdin_watcher);	1024	ev_io_start (loop, &stdin_watcher);
887		1025
888	ev_loop (loop, 0);	1026	ev_run (loop, 0);
889		1027
890	As you can see, you are responsible for allocating the memory for your	1028	As you can see, you are responsible for allocating the memory for your
891	watcher structures (and it is I<usually> a bad idea to do this on the	1029	watcher structures (and it is I<usually> a bad idea to do this on the
892	stack).	1030	stack).
893		1031
894	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1032	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
895	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1033	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
896		1034
897	Each watcher structure must be initialised by a call to C<ev_init	1035	Each watcher structure must be initialised by a call to C<ev_init (watcher
898	(watcher *, callback)>, which expects a callback to be provided. This	1036	*, callback)>, which expects a callback to be provided. This callback is
899	callback gets invoked each time the event occurs (or, in the case of I/O	1037	invoked each time the event occurs (or, in the case of I/O watchers, each
900	watchers, each time the event loop detects that the file descriptor given	1038	time the event loop detects that the file descriptor given is readable
901	is readable and/or writable).	1039	and/or writable).
902		1040
903	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1041	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
904	macro to configure it, with arguments specific to the watcher type. There	1042	macro to configure it, with arguments specific to the watcher type. There
905	is also a macro to combine initialisation and setting in one call: C<<	1043	is also a macro to combine initialisation and setting in one call: C<<
906	ev_TYPE_init (watcher *, callback, ...) >>.	1044	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
929	=item C<EV_WRITE>	1067	=item C<EV_WRITE>
930		1068
931	The file descriptor in the C<ev_io> watcher has become readable and/or	1069	The file descriptor in the C<ev_io> watcher has become readable and/or
932	writable.	1070	writable.
933		1071
934	=item C<EV_TIMEOUT>	1072	=item C<EV_TIMER>
935		1073
936	The C<ev_timer> watcher has timed out.	1074	The C<ev_timer> watcher has timed out.
937		1075
938	=item C<EV_PERIODIC>	1076	=item C<EV_PERIODIC>
939		1077
…		…
957		1095
958	=item C<EV_PREPARE>	1096	=item C<EV_PREPARE>
959		1097
960	=item C<EV_CHECK>	1098	=item C<EV_CHECK>
961		1099
962	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1100	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
963	to gather new events, and all C<ev_check> watchers are invoked just after	1101	to gather new events, and all C<ev_check> watchers are invoked just after
964	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1102	C<ev_run> has gathered them, but before it invokes any callbacks for any
965	received events. Callbacks of both watcher types can start and stop as	1103	received events. Callbacks of both watcher types can start and stop as
966	many watchers as they want, and all of them will be taken into account	1104	many watchers as they want, and all of them will be taken into account
967	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1105	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
968	C<ev_loop> from blocking).	1106	C<ev_run> from blocking).
969		1107
970	=item C<EV_EMBED>	1108	=item C<EV_EMBED>
971		1109
972	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1110	The embedded event loop specified in the C<ev_embed> watcher needs attention.
973		1111
…		…
1004	programs, though, as the fd could already be closed and reused for another	1142	programs, though, as the fd could already be closed and reused for another
1005	thing, so beware.	1143	thing, so beware.
1006		1144
1007	=back	1145	=back
1008		1146
		1147	=head2 WATCHER STATES
		1148
		1149	There are various watcher states mentioned throughout this manual -
		1150	active, pending and so on. In this section these states and the rules to
		1151	transition between them will be described in more detail - and while these
		1152	rules might look complicated, they usually do "the right thing".
		1153
		1154	=over 4
		1155
		1156	=item initialiased
		1157
		1158	Before a watcher can be registered with the event looop it has to be
		1159	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1160	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1161
		1162	In this state it is simply some block of memory that is suitable for use
		1163	in an event loop. It can be moved around, freed, reused etc. at will.
		1164
		1165	=item started/running/active
		1166
		1167	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1168	property of the event loop, and is actively waiting for events. While in
		1169	this state it cannot be accessed (except in a few documented ways), moved,
		1170	freed or anything else - the only legal thing is to keep a pointer to it,
		1171	and call libev functions on it that are documented to work on active watchers.
		1172
		1173	=item pending
		1174
		1175	If a watcher is active and libev determines that an event it is interested
		1176	in has occurred (such as a timer expiring), it will become pending. It will
		1177	stay in this pending state until either it is stopped or its callback is
		1178	about to be invoked, so it is not normally pending inside the watcher
		1179	callback.
		1180
		1181	The watcher might or might not be active while it is pending (for example,
		1182	an expired non-repeating timer can be pending but no longer active). If it
		1183	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1184	but it is still property of the event loop at this time, so cannot be
		1185	moved, freed or reused. And if it is active the rules described in the
		1186	previous item still apply.
		1187
		1188	It is also possible to feed an event on a watcher that is not active (e.g.
		1189	via C<ev_feed_event>), in which case it becomes pending without being
		1190	active.
		1191
		1192	=item stopped
		1193
		1194	A watcher can be stopped implicitly by libev (in which case it might still
		1195	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1196	latter will clear any pending state the watcher might be in, regardless
		1197	of whether it was active or not, so stopping a watcher explicitly before
		1198	freeing it is often a good idea.
		1199
		1200	While stopped (and not pending) the watcher is essentially in the
		1201	initialised state, that is it can be reused, moved, modified in any way
		1202	you wish.
		1203
		1204	=back
		1205
1009	=head2 GENERIC WATCHER FUNCTIONS	1206	=head2 GENERIC WATCHER FUNCTIONS
1010		1207
1011	=over 4	1208	=over 4
1012		1209
1013	=item C<ev_init> (ev_TYPE *watcher, callback)	1210	=item C<ev_init> (ev_TYPE *watcher, callback)
…		…
1029		1226
1030	ev_io w;	1227	ev_io w;
1031	ev_init (&w, my_cb);	1228	ev_init (&w, my_cb);
1032	ev_io_set (&w, STDIN_FILENO, EV_READ);	1229	ev_io_set (&w, STDIN_FILENO, EV_READ);
1033		1230
1034	=item C<ev_TYPE_set> (ev_TYPE *, [args])	1231	=item C<ev_TYPE_set> (ev_TYPE *watcher, [args])
1035		1232
1036	This macro initialises the type-specific parts of a watcher. You need to	1233	This macro initialises the type-specific parts of a watcher. You need to
1037	call C<ev_init> at least once before you call this macro, but you can	1234	call C<ev_init> at least once before you call this macro, but you can
1038	call C<ev_TYPE_set> any number of times. You must not, however, call this	1235	call C<ev_TYPE_set> any number of times. You must not, however, call this
1039	macro on a watcher that is active (it can be pending, however, which is a	1236	macro on a watcher that is active (it can be pending, however, which is a
…		…
1052		1249
1053	Example: Initialise and set an C<ev_io> watcher in one step.	1250	Example: Initialise and set an C<ev_io> watcher in one step.
1054		1251
1055	ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);	1252	ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
1056		1253
1057	=item C<ev_TYPE_start> (loop *, ev_TYPE *watcher)	1254	=item C<ev_TYPE_start> (loop, ev_TYPE *watcher)
1058		1255
1059	Starts (activates) the given watcher. Only active watchers will receive	1256	Starts (activates) the given watcher. Only active watchers will receive
1060	events. If the watcher is already active nothing will happen.	1257	events. If the watcher is already active nothing will happen.
1061		1258
1062	Example: Start the C<ev_io> watcher that is being abused as example in this	1259	Example: Start the C<ev_io> watcher that is being abused as example in this
1063	whole section.	1260	whole section.
1064		1261
1065	ev_io_start (EV_DEFAULT_UC, &w);	1262	ev_io_start (EV_DEFAULT_UC, &w);
1066		1263
1067	=item C<ev_TYPE_stop> (loop *, ev_TYPE *watcher)	1264	=item C<ev_TYPE_stop> (loop, ev_TYPE *watcher)
1068		1265
1069	Stops the given watcher if active, and clears the pending status (whether	1266	Stops the given watcher if active, and clears the pending status (whether
1070	the watcher was active or not).	1267	the watcher was active or not).
1071		1268
1072	It is possible that stopped watchers are pending - for example,	1269	It is possible that stopped watchers are pending - for example,
…		…
1097	=item ev_cb_set (ev_TYPE *watcher, callback)	1294	=item ev_cb_set (ev_TYPE *watcher, callback)
1098		1295
1099	Change the callback. You can change the callback at virtually any time	1296	Change the callback. You can change the callback at virtually any time
1100	(modulo threads).	1297	(modulo threads).
1101		1298
1102	=item ev_set_priority (ev_TYPE *watcher, priority)	1299	=item ev_set_priority (ev_TYPE *watcher, int priority)
1103		1300
1104	=item int ev_priority (ev_TYPE *watcher)	1301	=item int ev_priority (ev_TYPE *watcher)
1105		1302
1106	Set and query the priority of the watcher. The priority is a small	1303	Set and query the priority of the watcher. The priority is a small
1107	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>	1304	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
…		…
1138	returns its C<revents> bitset (as if its callback was invoked). If the	1335	returns its C<revents> bitset (as if its callback was invoked). If the
1139	watcher isn't pending it does nothing and returns C<0>.	1336	watcher isn't pending it does nothing and returns C<0>.
1140		1337
1141	Sometimes it can be useful to "poll" a watcher instead of waiting for its	1338	Sometimes it can be useful to "poll" a watcher instead of waiting for its
1142	callback to be invoked, which can be accomplished with this function.	1339	callback to be invoked, which can be accomplished with this function.
		1340
		1341	=item ev_feed_event (loop, ev_TYPE *watcher, int revents)
		1342
		1343	Feeds the given event set into the event loop, as if the specified event
		1344	had happened for the specified watcher (which must be a pointer to an
		1345	initialised but not necessarily started event watcher). Obviously you must
		1346	not free the watcher as long as it has pending events.
		1347
		1348	Stopping the watcher, letting libev invoke it, or calling
		1349	C<ev_clear_pending> will clear the pending event, even if the watcher was
		1350	not started in the first place.
		1351
		1352	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
		1353	functions that do not need a watcher.
1143		1354
1144	=back	1355	=back
1145		1356
1146		1357
1147	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1358	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
1258		1469
1259	For example, to emulate how many other event libraries handle priorities,	1470	For example, to emulate how many other event libraries handle priorities,
1260	you can associate an C<ev_idle> watcher to each such watcher, and in	1471	you can associate an C<ev_idle> watcher to each such watcher, and in
1261	the normal watcher callback, you just start the idle watcher. The real	1472	the normal watcher callback, you just start the idle watcher. The real
1262	processing is done in the idle watcher callback. This causes libev to	1473	processing is done in the idle watcher callback. This causes libev to
1263	continously poll and process kernel event data for the watcher, but when	1474	continuously poll and process kernel event data for the watcher, but when
1264	the lock-out case is known to be rare (which in turn is rare :), this is	1475	the lock-out case is known to be rare (which in turn is rare :), this is
1265	workable.	1476	workable.
1266		1477
1267	Usually, however, the lock-out model implemented that way will perform	1478	Usually, however, the lock-out model implemented that way will perform
1268	miserably under the type of load it was designed to handle. In that case,	1479	miserably under the type of load it was designed to handle. In that case,
…		…
1282	{	1493	{
1283	// stop the I/O watcher, we received the event, but	1494	// stop the I/O watcher, we received the event, but
1284	// are not yet ready to handle it.	1495	// are not yet ready to handle it.
1285	ev_io_stop (EV_A_ w);	1496	ev_io_stop (EV_A_ w);
1286		1497
1287	// start the idle watcher to ahndle the actual event.	1498	// start the idle watcher to handle the actual event.
1288	// it will not be executed as long as other watchers	1499	// it will not be executed as long as other watchers
1289	// with the default priority are receiving events.	1500	// with the default priority are receiving events.
1290	ev_idle_start (EV_A_ &idle);	1501	ev_idle_start (EV_A_ &idle);
1291	}	1502	}
1292		1503
…		…
1346		1557
1347	If you cannot use non-blocking mode, then force the use of a	1558	If you cannot use non-blocking mode, then force the use of a
1348	known-to-be-good backend (at the time of this writing, this includes only	1559	known-to-be-good backend (at the time of this writing, this includes only
1349	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1560	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1350	descriptors for which non-blocking operation makes no sense (such as	1561	descriptors for which non-blocking operation makes no sense (such as
1351	files) - libev doesn't guarentee any specific behaviour in that case.	1562	files) - libev doesn't guarantee any specific behaviour in that case.
1352		1563
1353	Another thing you have to watch out for is that it is quite easy to	1564	Another thing you have to watch out for is that it is quite easy to
1354	receive "spurious" readiness notifications, that is your callback might	1565	receive "spurious" readiness notifications, that is your callback might
1355	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1566	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1356	because there is no data. Not only are some backends known to create a	1567	because there is no data. Not only are some backends known to create a
…		…
1421		1632
1422	So when you encounter spurious, unexplained daemon exits, make sure you	1633	So when you encounter spurious, unexplained daemon exits, make sure you
1423	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1634	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1424	somewhere, as that would have given you a big clue).	1635	somewhere, as that would have given you a big clue).
1425		1636
		1637	=head3 The special problem of accept()ing when you can't
		1638
		1639	Many implementations of the POSIX C<accept> function (for example,
		1640	found in post-2004 Linux) have the peculiar behaviour of not removing a
		1641	connection from the pending queue in all error cases.
		1642
		1643	For example, larger servers often run out of file descriptors (because
		1644	of resource limits), causing C<accept> to fail with C<ENFILE> but not
		1645	rejecting the connection, leading to libev signalling readiness on
		1646	the next iteration again (the connection still exists after all), and
		1647	typically causing the program to loop at 100% CPU usage.
		1648
		1649	Unfortunately, the set of errors that cause this issue differs between
		1650	operating systems, there is usually little the app can do to remedy the
		1651	situation, and no known thread-safe method of removing the connection to
		1652	cope with overload is known (to me).
		1653
		1654	One of the easiest ways to handle this situation is to just ignore it
		1655	- when the program encounters an overload, it will just loop until the
		1656	situation is over. While this is a form of busy waiting, no OS offers an
		1657	event-based way to handle this situation, so it's the best one can do.
		1658
		1659	A better way to handle the situation is to log any errors other than
		1660	C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
		1661	messages, and continue as usual, which at least gives the user an idea of
		1662	what could be wrong ("raise the ulimit!"). For extra points one could stop
		1663	the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
		1664	usage.
		1665
		1666	If your program is single-threaded, then you could also keep a dummy file
		1667	descriptor for overload situations (e.g. by opening F</dev/null>), and
		1668	when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
		1669	close that fd, and create a new dummy fd. This will gracefully refuse
		1670	clients under typical overload conditions.
		1671
		1672	The last way to handle it is to simply log the error and C<exit>, as
		1673	is often done with C<malloc> failures, but this results in an easy
		1674	opportunity for a DoS attack.
1426		1675
1427	=head3 Watcher-Specific Functions	1676	=head3 Watcher-Specific Functions
1428		1677
1429	=over 4	1678	=over 4
1430		1679
…		…
1462	...	1711	...
1463	struct ev_loop *loop = ev_default_init (0);	1712	struct ev_loop *loop = ev_default_init (0);
1464	ev_io stdin_readable;	1713	ev_io stdin_readable;
1465	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1714	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1466	ev_io_start (loop, &stdin_readable);	1715	ev_io_start (loop, &stdin_readable);
1467	ev_loop (loop, 0);	1716	ev_run (loop, 0);
1468		1717
1469		1718
1470	=head2 C<ev_timer> - relative and optionally repeating timeouts	1719	=head2 C<ev_timer> - relative and optionally repeating timeouts
1471		1720
1472	Timer watchers are simple relative timers that generate an event after a	1721	Timer watchers are simple relative timers that generate an event after a
…		…
1480		1729
1481	The callback is guaranteed to be invoked only I<after> its timeout has	1730	The callback is guaranteed to be invoked only I<after> its timeout has
1482	passed (not I<at>, so on systems with very low-resolution clocks this	1731	passed (not I<at>, so on systems with very low-resolution clocks this
1483	might introduce a small delay). If multiple timers become ready during the	1732	might introduce a small delay). If multiple timers become ready during the
1484	same loop iteration then the ones with earlier time-out values are invoked	1733	same loop iteration then the ones with earlier time-out values are invoked
1485	before ones with later time-out values (but this is no longer true when a	1734	before ones of the same priority with later time-out values (but this is
1486	callback calls C<ev_loop> recursively).	1735	no longer true when a callback calls C<ev_run> recursively).
1487		1736
1488	=head3 Be smart about timeouts	1737	=head3 Be smart about timeouts
1489		1738
1490	Many real-world problems involve some kind of timeout, usually for error	1739	Many real-world problems involve some kind of timeout, usually for error
1491	recovery. A typical example is an HTTP request - if the other side hangs,	1740	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1577	ev_tstamp timeout = last_activity + 60.;	1826	ev_tstamp timeout = last_activity + 60.;
1578		1827
1579	// if last_activity + 60. is older than now, we did time out	1828	// if last_activity + 60. is older than now, we did time out
1580	if (timeout < now)	1829	if (timeout < now)
1581	{	1830	{
1582	// timeout occured, take action	1831	// timeout occurred, take action
1583	}	1832	}
1584	else	1833	else
1585	{	1834	{
1586	// callback was invoked, but there was some activity, re-arm	1835	// callback was invoked, but there was some activity, re-arm
1587	// the watcher to fire in last_activity + 60, which is	1836	// the watcher to fire in last_activity + 60, which is
…		…
1609	to the current time (meaning we just have some activity :), then call the	1858	to the current time (meaning we just have some activity :), then call the
1610	callback, which will "do the right thing" and start the timer:	1859	callback, which will "do the right thing" and start the timer:
1611		1860
1612	ev_init (timer, callback);	1861	ev_init (timer, callback);
1613	last_activity = ev_now (loop);	1862	last_activity = ev_now (loop);
1614	callback (loop, timer, EV_TIMEOUT);	1863	callback (loop, timer, EV_TIMER);
1615		1864
1616	And when there is some activity, simply store the current time in	1865	And when there is some activity, simply store the current time in
1617	C<last_activity>, no libev calls at all:	1866	C<last_activity>, no libev calls at all:
1618		1867
1619	last_actiivty = ev_now (loop);	1868	last_activity = ev_now (loop);
1620		1869
1621	This technique is slightly more complex, but in most cases where the	1870	This technique is slightly more complex, but in most cases where the
1622	time-out is unlikely to be triggered, much more efficient.	1871	time-out is unlikely to be triggered, much more efficient.
1623		1872
1624	Changing the timeout is trivial as well (if it isn't hard-coded in the	1873	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1662		1911
1663	=head3 The special problem of time updates	1912	=head3 The special problem of time updates
1664		1913
1665	Establishing the current time is a costly operation (it usually takes at	1914	Establishing the current time is a costly operation (it usually takes at
1666	least two system calls): EV therefore updates its idea of the current	1915	least two system calls): EV therefore updates its idea of the current
1667	time only before and after C<ev_loop> collects new events, which causes a	1916	time only before and after C<ev_run> collects new events, which causes a
1668	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1917	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1669	lots of events in one iteration.	1918	lots of events in one iteration.
1670		1919
1671	The relative timeouts are calculated relative to the C<ev_now ()>	1920	The relative timeouts are calculated relative to the C<ev_now ()>
1672	time. This is usually the right thing as this timestamp refers to the time	1921	time. This is usually the right thing as this timestamp refers to the time
…		…
1678		1927
1679	If the event loop is suspended for a long time, you can also force an	1928	If the event loop is suspended for a long time, you can also force an
1680	update of the time returned by C<ev_now ()> by calling C<ev_now_update	1929	update of the time returned by C<ev_now ()> by calling C<ev_now_update
1681	()>.	1930	()>.
1682		1931
		1932	=head3 The special problems of suspended animation
		1933
		1934	When you leave the server world it is quite customary to hit machines that
		1935	can suspend/hibernate - what happens to the clocks during such a suspend?
		1936
		1937	Some quick tests made with a Linux 2.6.28 indicate that a suspend freezes
		1938	all processes, while the clocks (C<times>, C<CLOCK_MONOTONIC>) continue
		1939	to run until the system is suspended, but they will not advance while the
		1940	system is suspended. That means, on resume, it will be as if the program
		1941	was frozen for a few seconds, but the suspend time will not be counted
		1942	towards C<ev_timer> when a monotonic clock source is used. The real time
		1943	clock advanced as expected, but if it is used as sole clocksource, then a
		1944	long suspend would be detected as a time jump by libev, and timers would
		1945	be adjusted accordingly.
		1946
		1947	I would not be surprised to see different behaviour in different between
		1948	operating systems, OS versions or even different hardware.
		1949
		1950	The other form of suspend (job control, or sending a SIGSTOP) will see a
		1951	time jump in the monotonic clocks and the realtime clock. If the program
		1952	is suspended for a very long time, and monotonic clock sources are in use,
		1953	then you can expect C<ev_timer>s to expire as the full suspension time
		1954	will be counted towards the timers. When no monotonic clock source is in
		1955	use, then libev will again assume a timejump and adjust accordingly.
		1956
		1957	It might be beneficial for this latter case to call C<ev_suspend>
		1958	and C<ev_resume> in code that handles C<SIGTSTP>, to at least get
		1959	deterministic behaviour in this case (you can do nothing against
		1960	C<SIGSTOP>).
		1961
1683	=head3 Watcher-Specific Functions and Data Members	1962	=head3 Watcher-Specific Functions and Data Members
1684		1963
1685	=over 4	1964	=over 4
1686		1965
1687	=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)	1966	=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)
…		…
1713	C<repeat> value), or reset the running timer to the C<repeat> value.	1992	C<repeat> value), or reset the running timer to the C<repeat> value.
1714		1993
1715	This sounds a bit complicated, see L<Be smart about timeouts>, above, for a	1994	This sounds a bit complicated, see L<Be smart about timeouts>, above, for a
1716	usage example.	1995	usage example.
1717		1996
		1997	=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
		1998
		1999	Returns the remaining time until a timer fires. If the timer is active,
		2000	then this time is relative to the current event loop time, otherwise it's
		2001	the timeout value currently configured.
		2002
		2003	That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
		2004	C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
		2005	will return C<4>. When the timer expires and is restarted, it will return
		2006	roughly C<7> (likely slightly less as callback invocation takes some time,
		2007	too), and so on.
		2008
1718	=item ev_tstamp repeat [read-write]	2009	=item ev_tstamp repeat [read-write]
1719		2010
1720	The current C<repeat> value. Will be used each time the watcher times out	2011	The current C<repeat> value. Will be used each time the watcher times out
1721	or C<ev_timer_again> is called, and determines the next timeout (if any),	2012	or C<ev_timer_again> is called, and determines the next timeout (if any),
1722	which is also when any modifications are taken into account.	2013	which is also when any modifications are taken into account.
…		…
1747	}	2038	}
1748		2039
1749	ev_timer mytimer;	2040	ev_timer mytimer;
1750	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2041	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1751	ev_timer_again (&mytimer); /* start timer */	2042	ev_timer_again (&mytimer); /* start timer */
1752	ev_loop (loop, 0);	2043	ev_run (loop, 0);
1753		2044
1754	// and in some piece of code that gets executed on any "activity":	2045	// and in some piece of code that gets executed on any "activity":
1755	// reset the timeout to start ticking again at 10 seconds	2046	// reset the timeout to start ticking again at 10 seconds
1756	ev_timer_again (&mytimer);	2047	ev_timer_again (&mytimer);
1757		2048
…		…
1783		2074
1784	As with timers, the callback is guaranteed to be invoked only when the	2075	As with timers, the callback is guaranteed to be invoked only when the
1785	point in time where it is supposed to trigger has passed. If multiple	2076	point in time where it is supposed to trigger has passed. If multiple
1786	timers become ready during the same loop iteration then the ones with	2077	timers become ready during the same loop iteration then the ones with
1787	earlier time-out values are invoked before ones with later time-out values	2078	earlier time-out values are invoked before ones with later time-out values
1788	(but this is no longer true when a callback calls C<ev_loop> recursively).	2079	(but this is no longer true when a callback calls C<ev_run> recursively).
1789		2080
1790	=head3 Watcher-Specific Functions and Data Members	2081	=head3 Watcher-Specific Functions and Data Members
1791		2082
1792	=over 4	2083	=over 4
1793		2084
…		…
1921	Example: Call a callback every hour, or, more precisely, whenever the	2212	Example: Call a callback every hour, or, more precisely, whenever the
1922	system time is divisible by 3600. The callback invocation times have	2213	system time is divisible by 3600. The callback invocation times have
1923	potentially a lot of jitter, but good long-term stability.	2214	potentially a lot of jitter, but good long-term stability.
1924		2215
1925	static void	2216	static void
1926	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2217	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
1927	{	2218	{
1928	... its now a full hour (UTC, or TAI or whatever your clock follows)	2219	... its now a full hour (UTC, or TAI or whatever your clock follows)
1929	}	2220	}
1930		2221
1931	ev_periodic hourly_tick;	2222	ev_periodic hourly_tick;
…		…
1957	Signal watchers will trigger an event when the process receives a specific	2248	Signal watchers will trigger an event when the process receives a specific
1958	signal one or more times. Even though signals are very asynchronous, libev	2249	signal one or more times. Even though signals are very asynchronous, libev
1959	will try it's best to deliver signals synchronously, i.e. as part of the	2250	will try it's best to deliver signals synchronously, i.e. as part of the
1960	normal event processing, like any other event.	2251	normal event processing, like any other event.
1961		2252
1962	If you want signals asynchronously, just use C<sigaction> as you would	2253	If you want signals to be delivered truly asynchronously, just use
1963	do without libev and forget about sharing the signal. You can even use	2254	C<sigaction> as you would do without libev and forget about sharing
1964	C<ev_async> from a signal handler to synchronously wake up an event loop.	2255	the signal. You can even use C<ev_async> from a signal handler to
		2256	synchronously wake up an event loop.
1965		2257
1966	You can configure as many watchers as you like per signal. Only when the	2258	You can configure as many watchers as you like for the same signal, but
		2259	only within the same loop, i.e. you can watch for C<SIGINT> in your
		2260	default loop and for C<SIGIO> in another loop, but you cannot watch for
		2261	C<SIGINT> in both the default loop and another loop at the same time. At
		2262	the moment, C<SIGCHLD> is permanently tied to the default loop.
		2263
1967	first watcher gets started will libev actually register a signal handler	2264	When the first watcher gets started will libev actually register something
1968	with the kernel (thus it coexists with your own signal handlers as long as	2265	with the kernel (thus it coexists with your own signal handlers as long as
1969	you don't register any with libev for the same signal). Similarly, when	2266	you don't register any with libev for the same signal).
1970	the last signal watcher for a signal is stopped, libev will reset the
1971	signal handler to SIG_DFL (regardless of what it was set to before).
1972		2267
1973	If possible and supported, libev will install its handlers with	2268	If possible and supported, libev will install its handlers with
1974	C<SA_RESTART> behaviour enabled, so system calls should not be unduly	2269	C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
1975	interrupted. If you have a problem with system calls getting interrupted by	2270	not be unduly interrupted. If you have a problem with system calls getting
1976	signals you can block all signals in an C<ev_check> watcher and unblock	2271	interrupted by signals you can block all signals in an C<ev_check> watcher
1977	them in an C<ev_prepare> watcher.	2272	and unblock them in an C<ev_prepare> watcher.
		2273
		2274	=head3 The special problem of inheritance over fork/execve/pthread_create
		2275
		2276	Both the signal mask (C<sigprocmask>) and the signal disposition
		2277	(C<sigaction>) are unspecified after starting a signal watcher (and after
		2278	stopping it again), that is, libev might or might not block the signal,
		2279	and might or might not set or restore the installed signal handler.
		2280
		2281	While this does not matter for the signal disposition (libev never
		2282	sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on
		2283	C<execve>), this matters for the signal mask: many programs do not expect
		2284	certain signals to be blocked.
		2285
		2286	This means that before calling C<exec> (from the child) you should reset
		2287	the signal mask to whatever "default" you expect (all clear is a good
		2288	choice usually).
		2289
		2290	The simplest way to ensure that the signal mask is reset in the child is
		2291	to install a fork handler with C<pthread_atfork> that resets it. That will
		2292	catch fork calls done by libraries (such as the libc) as well.
		2293
		2294	In current versions of libev, the signal will not be blocked indefinitely
		2295	unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
		2296	the window of opportunity for problems, it will not go away, as libev
		2297	I<has> to modify the signal mask, at least temporarily.
		2298
		2299	So I can't stress this enough: I<If you do not reset your signal mask when
		2300	you expect it to be empty, you have a race condition in your code>. This
		2301	is not a libev-specific thing, this is true for most event libraries.
1978		2302
1979	=head3 Watcher-Specific Functions and Data Members	2303	=head3 Watcher-Specific Functions and Data Members
1980		2304
1981	=over 4	2305	=over 4
1982		2306
…		…
1998	Example: Try to exit cleanly on SIGINT.	2322	Example: Try to exit cleanly on SIGINT.
1999		2323
2000	static void	2324	static void
2001	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2325	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2002	{	2326	{
2003	ev_unloop (loop, EVUNLOOP_ALL);	2327	ev_break (loop, EVBREAK_ALL);
2004	}	2328	}
2005		2329
2006	ev_signal signal_watcher;	2330	ev_signal signal_watcher;
2007	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2331	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2008	ev_signal_start (loop, &signal_watcher);	2332	ev_signal_start (loop, &signal_watcher);
…		…
2020	in the next callback invocation is not.	2344	in the next callback invocation is not.
2021		2345
2022	Only the default event loop is capable of handling signals, and therefore	2346	Only the default event loop is capable of handling signals, and therefore
2023	you can only register child watchers in the default event loop.	2347	you can only register child watchers in the default event loop.
2024		2348
		2349	Due to some design glitches inside libev, child watchers will always be
		2350	handled at maximum priority (their priority is set to C<EV_MAXPRI> by
		2351	libev)
		2352
2025	=head3 Process Interaction	2353	=head3 Process Interaction
2026		2354
2027	Libev grabs C<SIGCHLD> as soon as the default event loop is	2355	Libev grabs C<SIGCHLD> as soon as the default event loop is
2028	initialised. This is necessary to guarantee proper behaviour even if	2356	initialised. This is necessary to guarantee proper behaviour even if the
2029	the first child watcher is started after the child exits. The occurrence	2357	first child watcher is started after the child exits. The occurrence
2030	of C<SIGCHLD> is recorded asynchronously, but child reaping is done	2358	of C<SIGCHLD> is recorded asynchronously, but child reaping is done
2031	synchronously as part of the event loop processing. Libev always reaps all	2359	synchronously as part of the event loop processing. Libev always reaps all
2032	children, even ones not watched.	2360	children, even ones not watched.
2033		2361
2034	=head3 Overriding the Built-In Processing	2362	=head3 Overriding the Built-In Processing
…		…
2044	=head3 Stopping the Child Watcher	2372	=head3 Stopping the Child Watcher
2045		2373
2046	Currently, the child watcher never gets stopped, even when the	2374	Currently, the child watcher never gets stopped, even when the
2047	child terminates, so normally one needs to stop the watcher in the	2375	child terminates, so normally one needs to stop the watcher in the
2048	callback. Future versions of libev might stop the watcher automatically	2376	callback. Future versions of libev might stop the watcher automatically
2049	when a child exit is detected.	2377	when a child exit is detected (calling C<ev_child_stop> twice is not a
		2378	problem).
2050		2379
2051	=head3 Watcher-Specific Functions and Data Members	2380	=head3 Watcher-Specific Functions and Data Members
2052		2381
2053	=over 4	2382	=over 4
2054		2383
…		…
2389		2718
2390	Prepare and check watchers are usually (but not always) used in pairs:	2719	Prepare and check watchers are usually (but not always) used in pairs:
2391	prepare watchers get invoked before the process blocks and check watchers	2720	prepare watchers get invoked before the process blocks and check watchers
2392	afterwards.	2721	afterwards.
2393		2722
2394	You I<must not> call C<ev_loop> or similar functions that enter	2723	You I<must not> call C<ev_run> or similar functions that enter
2395	the current event loop from either C<ev_prepare> or C<ev_check>	2724	the current event loop from either C<ev_prepare> or C<ev_check>
2396	watchers. Other loops than the current one are fine, however. The	2725	watchers. Other loops than the current one are fine, however. The
2397	rationale behind this is that you do not need to check for recursion in	2726	rationale behind this is that you do not need to check for recursion in
2398	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2727	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2399	C<ev_check> so if you have one watcher of each kind they will always be	2728	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2567		2896
2568	if (timeout >= 0)	2897	if (timeout >= 0)
2569	// create/start timer	2898	// create/start timer
2570		2899
2571	// poll	2900	// poll
2572	ev_loop (EV_A_ 0);	2901	ev_run (EV_A_ 0);
2573		2902
2574	// stop timer again	2903	// stop timer again
2575	if (timeout >= 0)	2904	if (timeout >= 0)
2576	ev_timer_stop (EV_A_ &to);	2905	ev_timer_stop (EV_A_ &to);
2577		2906
…		…
2655	if you do not want that, you need to temporarily stop the embed watcher).	2984	if you do not want that, you need to temporarily stop the embed watcher).
2656		2985
2657	=item ev_embed_sweep (loop, ev_embed *)	2986	=item ev_embed_sweep (loop, ev_embed *)
2658		2987
2659	Make a single, non-blocking sweep over the embedded loop. This works	2988	Make a single, non-blocking sweep over the embedded loop. This works
2660	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2989	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2661	appropriate way for embedded loops.	2990	appropriate way for embedded loops.
2662		2991
2663	=item struct ev_loop *other [read-only]	2992	=item struct ev_loop *other [read-only]
2664		2993
2665	The embedded event loop.	2994	The embedded event loop.
…		…
2725	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3054	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2726	handlers will be invoked, too, of course.	3055	handlers will be invoked, too, of course.
2727		3056
2728	=head3 The special problem of life after fork - how is it possible?	3057	=head3 The special problem of life after fork - how is it possible?
2729		3058
2730	Most uses of C<fork()> consist of forking, then some simple calls to ste	3059	Most uses of C<fork()> consist of forking, then some simple calls to set
2731	up/change the process environment, followed by a call to C<exec()>. This	3060	up/change the process environment, followed by a call to C<exec()>. This
2732	sequence should be handled by libev without any problems.	3061	sequence should be handled by libev without any problems.
2733		3062
2734	This changes when the application actually wants to do event handling	3063	This changes when the application actually wants to do event handling
2735	in the child, or both parent in child, in effect "continuing" after the	3064	in the child, or both parent in child, in effect "continuing" after the
…		…
2751	disadvantage of having to use multiple event loops (which do not support	3080	disadvantage of having to use multiple event loops (which do not support
2752	signal watchers).	3081	signal watchers).
2753		3082
2754	When this is not possible, or you want to use the default loop for	3083	When this is not possible, or you want to use the default loop for
2755	other reasons, then in the process that wants to start "fresh", call	3084	other reasons, then in the process that wants to start "fresh", call
2756	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3085	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2757	the default loop will "orphan" (not stop) all registered watchers, so you	3086	Destroying the default loop will "orphan" (not stop) all registered
2758	have to be careful not to execute code that modifies those watchers. Note	3087	watchers, so you have to be careful not to execute code that modifies
2759	also that in that case, you have to re-register any signal watchers.	3088	those watchers. Note also that in that case, you have to re-register any
		3089	signal watchers.
2760		3090
2761	=head3 Watcher-Specific Functions and Data Members	3091	=head3 Watcher-Specific Functions and Data Members
2762		3092
2763	=over 4	3093	=over 4
2764		3094
…		…
2769	believe me.	3099	believe me.
2770		3100
2771	=back	3101	=back
2772		3102
2773		3103
2774	=head2 C<ev_async> - how to wake up another event loop	3104	=head2 C<ev_async> - how to wake up an event loop
2775		3105
2776	In general, you cannot use an C<ev_loop> from multiple threads or other	3106	In general, you cannot use an C<ev_run> from multiple threads or other
2777	asynchronous sources such as signal handlers (as opposed to multiple event	3107	asynchronous sources such as signal handlers (as opposed to multiple event
2778	loops - those are of course safe to use in different threads).	3108	loops - those are of course safe to use in different threads).
2779		3109
2780	Sometimes, however, you need to wake up another event loop you do not	3110	Sometimes, however, you need to wake up an event loop you do not control,
2781	control, for example because it belongs to another thread. This is what	3111	for example because it belongs to another thread. This is what C<ev_async>
2782	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3112	watchers do: as long as the C<ev_async> watcher is active, you can signal
2783	can signal it by calling C<ev_async_send>, which is thread- and signal	3113	it by calling C<ev_async_send>, which is thread- and signal safe.
2784	safe.
2785		3114
2786	This functionality is very similar to C<ev_signal> watchers, as signals,	3115	This functionality is very similar to C<ev_signal> watchers, as signals,
2787	too, are asynchronous in nature, and signals, too, will be compressed	3116	too, are asynchronous in nature, and signals, too, will be compressed
2788	(i.e. the number of callback invocations may be less than the number of	3117	(i.e. the number of callback invocations may be less than the number of
2789	C<ev_async_sent> calls).	3118	C<ev_async_sent> calls).
…		…
2794	=head3 Queueing	3123	=head3 Queueing
2795		3124
2796	C<ev_async> does not support queueing of data in any way. The reason	3125	C<ev_async> does not support queueing of data in any way. The reason
2797	is that the author does not know of a simple (or any) algorithm for a	3126	is that the author does not know of a simple (or any) algorithm for a
2798	multiple-writer-single-reader queue that works in all cases and doesn't	3127	multiple-writer-single-reader queue that works in all cases and doesn't
2799	need elaborate support such as pthreads.	3128	need elaborate support such as pthreads or unportable memory access
		3129	semantics.
2800		3130
2801	That means that if you want to queue data, you have to provide your own	3131	That means that if you want to queue data, you have to provide your own
2802	queue. But at least I can tell you how to implement locking around your	3132	queue. But at least I can tell you how to implement locking around your
2803	queue:	3133	queue:
2804		3134
…		…
2943		3273
2944	If C<timeout> is less than 0, then no timeout watcher will be	3274	If C<timeout> is less than 0, then no timeout watcher will be
2945	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3275	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
2946	repeat = 0) will be started. C<0> is a valid timeout.	3276	repeat = 0) will be started. C<0> is a valid timeout.
2947		3277
2948	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	3278	The callback has the type C<void (*cb)(int revents, void *arg)> and is
2949	passed an C<revents> set like normal event callbacks (a combination of	3279	passed an C<revents> set like normal event callbacks (a combination of
2950	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3280	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
2951	value passed to C<ev_once>. Note that it is possible to receive I<both>	3281	value passed to C<ev_once>. Note that it is possible to receive I<both>
2952	a timeout and an io event at the same time - you probably should give io	3282	a timeout and an io event at the same time - you probably should give io
2953	events precedence.	3283	events precedence.
2954		3284
2955	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3285	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
2956		3286
2957	static void stdin_ready (int revents, void *arg)	3287	static void stdin_ready (int revents, void *arg)
2958	{	3288	{
2959	if (revents & EV_READ)	3289	if (revents & EV_READ)
2960	/* stdin might have data for us, joy! */;	3290	/* stdin might have data for us, joy! */;
2961	else if (revents & EV_TIMEOUT)	3291	else if (revents & EV_TIMER)
2962	/* doh, nothing entered */;	3292	/* doh, nothing entered */;
2963	}	3293	}
2964		3294
2965	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3295	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2966		3296
2967	=item ev_feed_event (struct ev_loop *, watcher *, int revents)
2968
2969	Feeds the given event set into the event loop, as if the specified event
2970	had happened for the specified watcher (which must be a pointer to an
2971	initialised but not necessarily started event watcher).
2972
2973	=item ev_feed_fd_event (struct ev_loop *, int fd, int revents)	3297	=item ev_feed_fd_event (loop, int fd, int revents)
2974		3298
2975	Feed an event on the given fd, as if a file descriptor backend detected	3299	Feed an event on the given fd, as if a file descriptor backend detected
2976	the given events it.	3300	the given events it.
2977		3301
2978	=item ev_feed_signal_event (struct ev_loop *loop, int signum)	3302	=item ev_feed_signal_event (loop, int signum)
2979		3303
2980	Feed an event as if the given signal occurred (C<loop> must be the default	3304	Feed an event as if the given signal occurred (C<loop> must be the default
2981	loop!).	3305	loop!).
2982		3306
2983	=back	3307	=back
…		…
3063		3387
3064	=over 4	3388	=over 4
3065		3389
3066	=item ev::TYPE::TYPE ()	3390	=item ev::TYPE::TYPE ()
3067		3391
3068	=item ev::TYPE::TYPE (struct ev_loop *)	3392	=item ev::TYPE::TYPE (loop)
3069		3393
3070	=item ev::TYPE::~TYPE	3394	=item ev::TYPE::~TYPE
3071		3395
3072	The constructor (optionally) takes an event loop to associate the watcher	3396	The constructor (optionally) takes an event loop to associate the watcher
3073	with. If it is omitted, it will use C<EV_DEFAULT>.	3397	with. If it is omitted, it will use C<EV_DEFAULT>.
…		…
3106	myclass obj;	3430	myclass obj;
3107	ev::io iow;	3431	ev::io iow;
3108	iow.set <myclass, &myclass::io_cb> (&obj);	3432	iow.set <myclass, &myclass::io_cb> (&obj);
3109		3433
3110	=item w->set (object *)	3434	=item w->set (object *)
3111
3112	This is an B<experimental> feature that might go away in a future version.
3113		3435
3114	This is a variation of a method callback - leaving out the method to call	3436	This is a variation of a method callback - leaving out the method to call
3115	will default the method to C<operator ()>, which makes it possible to use	3437	will default the method to C<operator ()>, which makes it possible to use
3116	functor objects without having to manually specify the C<operator ()> all	3438	functor objects without having to manually specify the C<operator ()> all
3117	the time. Incidentally, you can then also leave out the template argument	3439	the time. Incidentally, you can then also leave out the template argument
…		…
3150	Example: Use a plain function as callback.	3472	Example: Use a plain function as callback.
3151		3473
3152	static void io_cb (ev::io &w, int revents) { }	3474	static void io_cb (ev::io &w, int revents) { }
3153	iow.set <io_cb> ();	3475	iow.set <io_cb> ();
3154		3476
3155	=item w->set (struct ev_loop *)	3477	=item w->set (loop)
3156		3478
3157	Associates a different C<struct ev_loop> with this watcher. You can only	3479	Associates a different C<struct ev_loop> with this watcher. You can only
3158	do this when the watcher is inactive (and not pending either).	3480	do this when the watcher is inactive (and not pending either).
3159		3481
3160	=item w->set ([arguments])	3482	=item w->set ([arguments])
3161		3483
3162	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3484	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3163	called at least once. Unlike the C counterpart, an active watcher gets	3485	method or a suitable start method must be called at least once. Unlike the
3164	automatically stopped and restarted when reconfiguring it with this	3486	C counterpart, an active watcher gets automatically stopped and restarted
3165	method.	3487	when reconfiguring it with this method.
3166		3488
3167	=item w->start ()	3489	=item w->start ()
3168		3490
3169	Starts the watcher. Note that there is no C<loop> argument, as the	3491	Starts the watcher. Note that there is no C<loop> argument, as the
3170	constructor already stores the event loop.	3492	constructor already stores the event loop.
3171		3493
		3494	=item w->start ([arguments])
		3495
		3496	Instead of calling C<set> and C<start> methods separately, it is often
		3497	convenient to wrap them in one call. Uses the same type of arguments as
		3498	the configure C<set> method of the watcher.
		3499
3172	=item w->stop ()	3500	=item w->stop ()
3173		3501
3174	Stops the watcher if it is active. Again, no C<loop> argument.	3502	Stops the watcher if it is active. Again, no C<loop> argument.
3175		3503
3176	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3504	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3188		3516
3189	=back	3517	=back
3190		3518
3191	=back	3519	=back
3192		3520
3193	Example: Define a class with an IO and idle watcher, start one of them in	3521	Example: Define a class with two I/O and idle watchers, start the I/O
3194	the constructor.	3522	watchers in the constructor.
3195		3523
3196	class myclass	3524	class myclass
3197	{	3525	{
3198	ev::io io ; void io_cb (ev::io &w, int revents);	3526	ev::io io ; void io_cb (ev::io &w, int revents);
		3527	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3199	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3528	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3200		3529
3201	myclass (int fd)	3530	myclass (int fd)
3202	{	3531	{
3203	io .set <myclass, &myclass::io_cb > (this);	3532	io .set <myclass, &myclass::io_cb > (this);
		3533	io2 .set <myclass, &myclass::io2_cb > (this);
3204	idle.set <myclass, &myclass::idle_cb> (this);	3534	idle.set <myclass, &myclass::idle_cb> (this);
3205		3535
3206	io.start (fd, ev::READ);	3536	io.set (fd, ev::WRITE); // configure the watcher
		3537	io.start (); // start it whenever convenient
		3538
		3539	io2.start (fd, ev::READ); // set + start in one call
3207	}	3540	}
3208	};	3541	};
3209		3542
3210		3543
3211	=head1 OTHER LANGUAGE BINDINGS	3544	=head1 OTHER LANGUAGE BINDINGS
…		…
3257	=item Ocaml	3590	=item Ocaml
3258		3591
3259	Erkki Seppala has written Ocaml bindings for libev, to be found at	3592	Erkki Seppala has written Ocaml bindings for libev, to be found at
3260	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.	3593	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
3261		3594
		3595	=item Lua
		3596
		3597	Brian Maher has written a partial interface to libev for lua (at the
		3598	time of this writing, only C<ev_io> and C<ev_timer>), to be found at
		3599	L<http://github.com/brimworks/lua-ev>.
		3600
3262	=back	3601	=back
3263		3602
3264		3603
3265	=head1 MACRO MAGIC	3604	=head1 MACRO MAGIC
3266		3605
…		…
3279	loop argument"). The C<EV_A> form is used when this is the sole argument,	3618	loop argument"). The C<EV_A> form is used when this is the sole argument,
3280	C<EV_A_> is used when other arguments are following. Example:	3619	C<EV_A_> is used when other arguments are following. Example:
3281		3620
3282	ev_unref (EV_A);	3621	ev_unref (EV_A);
3283	ev_timer_add (EV_A_ watcher);	3622	ev_timer_add (EV_A_ watcher);
3284	ev_loop (EV_A_ 0);	3623	ev_run (EV_A_ 0);
3285		3624
3286	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3625	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3287	which is often provided by the following macro.	3626	which is often provided by the following macro.
3288		3627
3289	=item C<EV_P>, C<EV_P_>	3628	=item C<EV_P>, C<EV_P_>
…		…
3329	}	3668	}
3330		3669
3331	ev_check check;	3670	ev_check check;
3332	ev_check_init (&check, check_cb);	3671	ev_check_init (&check, check_cb);
3333	ev_check_start (EV_DEFAULT_ &check);	3672	ev_check_start (EV_DEFAULT_ &check);
3334	ev_loop (EV_DEFAULT_ 0);	3673	ev_run (EV_DEFAULT_ 0);
3335		3674
3336	=head1 EMBEDDING	3675	=head1 EMBEDDING
3337		3676
3338	Libev can (and often is) directly embedded into host	3677	Libev can (and often is) directly embedded into host
3339	applications. Examples of applications that embed it include the Deliantra	3678	applications. Examples of applications that embed it include the Deliantra
…		…
3419	libev.m4	3758	libev.m4
3420		3759
3421	=head2 PREPROCESSOR SYMBOLS/MACROS	3760	=head2 PREPROCESSOR SYMBOLS/MACROS
3422		3761
3423	Libev can be configured via a variety of preprocessor symbols you have to	3762	Libev can be configured via a variety of preprocessor symbols you have to
3424	define before including any of its files. The default in the absence of	3763	define before including (or compiling) any of its files. The default in
3425	autoconf is documented for every option.	3764	the absence of autoconf is documented for every option.
		3765
		3766	Symbols marked with "(h)" do not change the ABI, and can have different
		3767	values when compiling libev vs. including F<ev.h>, so it is permissible
		3768	to redefine them before including F<ev.h> without breaking compatibility
		3769	to a compiled library. All other symbols change the ABI, which means all
		3770	users of libev and the libev code itself must be compiled with compatible
		3771	settings.
3426		3772
3427	=over 4	3773	=over 4
3428		3774
		3775	=item EV_COMPAT3 (h)
		3776
		3777	Backwards compatibility is a major concern for libev. This is why this
		3778	release of libev comes with wrappers for the functions and symbols that
		3779	have been renamed between libev version 3 and 4.
		3780
		3781	You can disable these wrappers (to test compatibility with future
		3782	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3783	sources. This has the additional advantage that you can drop the C<struct>
		3784	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3785	typedef in that case.
		3786
		3787	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3788	and in some even more future version the compatibility code will be
		3789	removed completely.
		3790
3429	=item EV_STANDALONE	3791	=item EV_STANDALONE (h)
3430		3792
3431	Must always be C<1> if you do not use autoconf configuration, which	3793	Must always be C<1> if you do not use autoconf configuration, which
3432	keeps libev from including F<config.h>, and it also defines dummy	3794	keeps libev from including F<config.h>, and it also defines dummy
3433	implementations for some libevent functions (such as logging, which is not	3795	implementations for some libevent functions (such as logging, which is not
3434	supported). It will also not define any of the structs usually found in	3796	supported). It will also not define any of the structs usually found in
3435	F<event.h> that are not directly supported by the libev core alone.	3797	F<event.h> that are not directly supported by the libev core alone.
3436		3798
3437	In stanbdalone mode, libev will still try to automatically deduce the	3799	In standalone mode, libev will still try to automatically deduce the
3438	configuration, but has to be more conservative.	3800	configuration, but has to be more conservative.
3439		3801
3440	=item EV_USE_MONOTONIC	3802	=item EV_USE_MONOTONIC
3441		3803
3442	If defined to be C<1>, libev will try to detect the availability of the	3804	If defined to be C<1>, libev will try to detect the availability of the
…		…
3507	be used is the winsock select). This means that it will call	3869	be used is the winsock select). This means that it will call
3508	C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,	3870	C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,
3509	it is assumed that all these functions actually work on fds, even	3871	it is assumed that all these functions actually work on fds, even
3510	on win32. Should not be defined on non-win32 platforms.	3872	on win32. Should not be defined on non-win32 platforms.
3511		3873
3512	=item EV_FD_TO_WIN32_HANDLE	3874	=item EV_FD_TO_WIN32_HANDLE(fd)
3513		3875
3514	If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map	3876	If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map
3515	file descriptors to socket handles. When not defining this symbol (the	3877	file descriptors to socket handles. When not defining this symbol (the
3516	default), then libev will call C<_get_osfhandle>, which is usually	3878	default), then libev will call C<_get_osfhandle>, which is usually
3517	correct. In some cases, programs use their own file descriptor management,	3879	correct. In some cases, programs use their own file descriptor management,
3518	in which case they can provide this function to map fds to socket handles.	3880	in which case they can provide this function to map fds to socket handles.
		3881
		3882	=item EV_WIN32_HANDLE_TO_FD(handle)
		3883
		3884	If C<EV_SELECT_IS_WINSOCKET> then libev maps handles to file descriptors
		3885	using the standard C<_open_osfhandle> function. For programs implementing
		3886	their own fd to handle mapping, overwriting this function makes it easier
		3887	to do so. This can be done by defining this macro to an appropriate value.
		3888
		3889	=item EV_WIN32_CLOSE_FD(fd)
		3890
		3891	If programs implement their own fd to handle mapping on win32, then this
		3892	macro can be used to override the C<close> function, useful to unregister
		3893	file descriptors again. Note that the replacement function has to close
		3894	the underlying OS handle.
3519		3895
3520	=item EV_USE_POLL	3896	=item EV_USE_POLL
3521		3897
3522	If defined to be C<1>, libev will compile in support for the C<poll>(2)	3898	If defined to be C<1>, libev will compile in support for the C<poll>(2)
3523	backend. Otherwise it will be enabled on non-win32 platforms. It	3899	backend. Otherwise it will be enabled on non-win32 platforms. It
…		…
3570	as well as for signal and thread safety in C<ev_async> watchers.	3946	as well as for signal and thread safety in C<ev_async> watchers.
3571		3947
3572	In the absence of this define, libev will use C<sig_atomic_t volatile>	3948	In the absence of this define, libev will use C<sig_atomic_t volatile>
3573	(from F<signal.h>), which is usually good enough on most platforms.	3949	(from F<signal.h>), which is usually good enough on most platforms.
3574		3950
3575	=item EV_H	3951	=item EV_H (h)
3576		3952
3577	The name of the F<ev.h> header file used to include it. The default if	3953	The name of the F<ev.h> header file used to include it. The default if
3578	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be	3954	undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
3579	used to virtually rename the F<ev.h> header file in case of conflicts.	3955	used to virtually rename the F<ev.h> header file in case of conflicts.
3580		3956
3581	=item EV_CONFIG_H	3957	=item EV_CONFIG_H (h)
3582		3958
3583	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	3959	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
3584	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	3960	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
3585	C<EV_H>, above.	3961	C<EV_H>, above.
3586		3962
3587	=item EV_EVENT_H	3963	=item EV_EVENT_H (h)
3588		3964
3589	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	3965	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
3590	of how the F<event.h> header can be found, the default is C<"event.h">.	3966	of how the F<event.h> header can be found, the default is C<"event.h">.
3591		3967
3592	=item EV_PROTOTYPES	3968	=item EV_PROTOTYPES (h)
3593		3969
3594	If defined to be C<0>, then F<ev.h> will not define any function	3970	If defined to be C<0>, then F<ev.h> will not define any function
3595	prototypes, but still define all the structs and other symbols. This is	3971	prototypes, but still define all the structs and other symbols. This is
3596	occasionally useful if you want to provide your own wrapper functions	3972	occasionally useful if you want to provide your own wrapper functions
3597	around libev functions.	3973	around libev functions.
…		…
3619	fine.	3995	fine.
3620		3996
3621	If your embedding application does not need any priorities, defining these	3997	If your embedding application does not need any priorities, defining these
3622	both to C<0> will save some memory and CPU.	3998	both to C<0> will save some memory and CPU.
3623		3999
3624	=item EV_PERIODIC_ENABLE	4000	=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
		4001	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
		4002	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3625		4003
3626	If undefined or defined to be C<1>, then periodic timers are supported. If	4004	If undefined or defined to be C<1> (and the platform supports it), then
3627	defined to be C<0>, then they are not. Disabling them saves a few kB of	4005	the respective watcher type is supported. If defined to be C<0>, then it
3628	code.	4006	is not. Disabling watcher types mainly saves code size.
3629		4007
3630	=item EV_IDLE_ENABLE	4008	=item EV_FEATURES
3631
3632	If undefined or defined to be C<1>, then idle watchers are supported. If
3633	defined to be C<0>, then they are not. Disabling them saves a few kB of
3634	code.
3635
3636	=item EV_EMBED_ENABLE
3637
3638	If undefined or defined to be C<1>, then embed watchers are supported. If
3639	defined to be C<0>, then they are not. Embed watchers rely on most other
3640	watcher types, which therefore must not be disabled.
3641
3642	=item EV_STAT_ENABLE
3643
3644	If undefined or defined to be C<1>, then stat watchers are supported. If
3645	defined to be C<0>, then they are not.
3646
3647	=item EV_FORK_ENABLE
3648
3649	If undefined or defined to be C<1>, then fork watchers are supported. If
3650	defined to be C<0>, then they are not.
3651
3652	=item EV_ASYNC_ENABLE
3653
3654	If undefined or defined to be C<1>, then async watchers are supported. If
3655	defined to be C<0>, then they are not.
3656
3657	=item EV_MINIMAL
3658		4009
3659	If you need to shave off some kilobytes of code at the expense of some	4010	If you need to shave off some kilobytes of code at the expense of some
3660	speed, define this symbol to C<1>. Currently this is used to override some	4011	speed (but with the full API), you can define this symbol to request
3661	inlining decisions, saves roughly 30% code size on amd64. It also selects a	4012	certain subsets of functionality. The default is to enable all features
3662	much smaller 2-heap for timer management over the default 4-heap.	4013	that can be enabled on the platform.
		4014
		4015	A typical way to use this symbol is to define it to C<0> (or to a bitset
		4016	with some broad features you want) and then selectively re-enable
		4017	additional parts you want, for example if you want everything minimal,
		4018	but multiple event loop support, async and child watchers and the poll
		4019	backend, use this:
		4020
		4021	#define EV_FEATURES 0
		4022	#define EV_MULTIPLICITY 1
		4023	#define EV_USE_POLL 1
		4024	#define EV_CHILD_ENABLE 1
		4025	#define EV_ASYNC_ENABLE 1
		4026
		4027	The actual value is a bitset, it can be a combination of the following
		4028	values:
		4029
		4030	=over 4
		4031
		4032	=item C<1> - faster/larger code
		4033
		4034	Use larger code to speed up some operations.
		4035
		4036	Currently this is used to override some inlining decisions (enlarging the
		4037	code size by roughly 30% on amd64).
		4038
		4039	When optimising for size, use of compiler flags such as C<-Os> with
		4040	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
		4041	assertions.
		4042
		4043	=item C<2> - faster/larger data structures
		4044
		4045	Replaces the small 2-heap for timer management by a faster 4-heap, larger
		4046	hash table sizes and so on. This will usually further increase code size
		4047	and can additionally have an effect on the size of data structures at
		4048	runtime.
		4049
		4050	=item C<4> - full API configuration
		4051
		4052	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
		4053	enables multiplicity (C<EV_MULTIPLICITY>=1).
		4054
		4055	=item C<8> - full API
		4056
		4057	This enables a lot of the "lesser used" API functions. See C<ev.h> for
		4058	details on which parts of the API are still available without this
		4059	feature, and do not complain if this subset changes over time.
		4060
		4061	=item C<16> - enable all optional watcher types
		4062
		4063	Enables all optional watcher types. If you want to selectively enable
		4064	only some watcher types other than I/O and timers (e.g. prepare,
		4065	embed, async, child...) you can enable them manually by defining
		4066	C<EV_watchertype_ENABLE> to C<1> instead.
		4067
		4068	=item C<32> - enable all backends
		4069
		4070	This enables all backends - without this feature, you need to enable at
		4071	least one backend manually (C<EV_USE_SELECT> is a good choice).
		4072
		4073	=item C<64> - enable OS-specific "helper" APIs
		4074
		4075	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
		4076	default.
		4077
		4078	=back
		4079
		4080	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
		4081	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
		4082	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
		4083	watchers, timers and monotonic clock support.
		4084
		4085	With an intelligent-enough linker (gcc+binutils are intelligent enough
		4086	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
		4087	your program might be left out as well - a binary starting a timer and an
		4088	I/O watcher then might come out at only 5Kb.
		4089
		4090	=item EV_AVOID_STDIO
		4091
		4092	If this is set to C<1> at compiletime, then libev will avoid using stdio
		4093	functions (printf, scanf, perror etc.). This will increase the code size
		4094	somewhat, but if your program doesn't otherwise depend on stdio and your
		4095	libc allows it, this avoids linking in the stdio library which is quite
		4096	big.
		4097
		4098	Note that error messages might become less precise when this option is
		4099	enabled.
		4100
		4101	=item EV_NSIG
		4102
		4103	The highest supported signal number, +1 (or, the number of
		4104	signals): Normally, libev tries to deduce the maximum number of signals
		4105	automatically, but sometimes this fails, in which case it can be
		4106	specified. Also, using a lower number than detected (C<32> should be
		4107	good for about any system in existence) can save some memory, as libev
		4108	statically allocates some 12-24 bytes per signal number.
3663		4109
3664	=item EV_PID_HASHSIZE	4110	=item EV_PID_HASHSIZE
3665		4111
3666	C<ev_child> watchers use a small hash table to distribute workload by	4112	C<ev_child> watchers use a small hash table to distribute workload by
3667	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	4113	pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
3668	than enough. If you need to manage thousands of children you might want to	4114	usually more than enough. If you need to manage thousands of children you
3669	increase this value (I<must> be a power of two).	4115	might want to increase this value (I<must> be a power of two).
3670		4116
3671	=item EV_INOTIFY_HASHSIZE	4117	=item EV_INOTIFY_HASHSIZE
3672		4118
3673	C<ev_stat> watchers use a small hash table to distribute workload by	4119	C<ev_stat> watchers use a small hash table to distribute workload by
3674	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	4120	inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
3675	usually more than enough. If you need to manage thousands of C<ev_stat>	4121	disabled), usually more than enough. If you need to manage thousands of
3676	watchers you might want to increase this value (I<must> be a power of	4122	C<ev_stat> watchers you might want to increase this value (I<must> be a
3677	two).	4123	power of two).
3678		4124
3679	=item EV_USE_4HEAP	4125	=item EV_USE_4HEAP
3680		4126
3681	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4127	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3682	timer and periodics heaps, libev uses a 4-heap when this symbol is defined	4128	timer and periodics heaps, libev uses a 4-heap when this symbol is defined
3683	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably	4129	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
3684	faster performance with many (thousands) of watchers.	4130	faster performance with many (thousands) of watchers.
3685		4131
3686	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4132	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3687	(disabled).	4133	will be C<0>.
3688		4134
3689	=item EV_HEAP_CACHE_AT	4135	=item EV_HEAP_CACHE_AT
3690		4136
3691	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4137	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3692	timer and periodics heaps, libev can cache the timestamp (I<at>) within	4138	timer and periodics heaps, libev can cache the timestamp (I<at>) within
3693	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	4139	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3694	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	4140	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3695	but avoids random read accesses on heap changes. This improves performance	4141	but avoids random read accesses on heap changes. This improves performance
3696	noticeably with many (hundreds) of watchers.	4142	noticeably with many (hundreds) of watchers.
3697		4143
3698	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4144	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3699	(disabled).	4145	will be C<0>.
3700		4146
3701	=item EV_VERIFY	4147	=item EV_VERIFY
3702		4148
3703	Controls how much internal verification (see C<ev_loop_verify ()>) will	4149	Controls how much internal verification (see C<ev_verify ()>) will
3704	be done: If set to C<0>, no internal verification code will be compiled	4150	be done: If set to C<0>, no internal verification code will be compiled
3705	in. If set to C<1>, then verification code will be compiled in, but not	4151	in. If set to C<1>, then verification code will be compiled in, but not
3706	called. If set to C<2>, then the internal verification code will be	4152	called. If set to C<2>, then the internal verification code will be
3707	called once per loop, which can slow down libev. If set to C<3>, then the	4153	called once per loop, which can slow down libev. If set to C<3>, then the
3708	verification code will be called very frequently, which will slow down	4154	verification code will be called very frequently, which will slow down
3709	libev considerably.	4155	libev considerably.
3710		4156
3711	The default is C<1>, unless C<EV_MINIMAL> is set, in which case it will be	4157	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3712	C<0>.	4158	will be C<0>.
3713		4159
3714	=item EV_COMMON	4160	=item EV_COMMON
3715		4161
3716	By default, all watchers have a C<void *data> member. By redefining	4162	By default, all watchers have a C<void *data> member. By redefining
3717	this macro to a something else you can include more and other types of	4163	this macro to something else you can include more and other types of
3718	members. You have to define it each time you include one of the files,	4164	members. You have to define it each time you include one of the files,
3719	though, and it must be identical each time.	4165	though, and it must be identical each time.
3720		4166
3721	For example, the perl EV module uses something like this:	4167	For example, the perl EV module uses something like this:
3722		4168
…		…
3775	file.	4221	file.
3776		4222
3777	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4223	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
3778	that everybody includes and which overrides some configure choices:	4224	that everybody includes and which overrides some configure choices:
3779		4225
3780	#define EV_MINIMAL 1	4226	#define EV_FEATURES 8
3781	#define EV_USE_POLL 0	4227	#define EV_USE_SELECT 1
3782	#define EV_MULTIPLICITY 0
3783	#define EV_PERIODIC_ENABLE 0	4228	#define EV_PREPARE_ENABLE 1
		4229	#define EV_IDLE_ENABLE 1
3784	#define EV_STAT_ENABLE 0	4230	#define EV_SIGNAL_ENABLE 1
3785	#define EV_FORK_ENABLE 0	4231	#define EV_CHILD_ENABLE 1
		4232	#define EV_USE_STDEXCEPT 0
3786	#define EV_CONFIG_H <config.h>	4233	#define EV_CONFIG_H <config.h>
3787	#define EV_MINPRI 0
3788	#define EV_MAXPRI 0
3789		4234
3790	#include "ev++.h"	4235	#include "ev++.h"
3791		4236
3792	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4237	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3793		4238
…		…
3853	default loop and triggering an C<ev_async> watcher from the default loop	4298	default loop and triggering an C<ev_async> watcher from the default loop
3854	watcher callback into the event loop interested in the signal.	4299	watcher callback into the event loop interested in the signal.
3855		4300
3856	=back	4301	=back
3857		4302
		4303	=head4 THREAD LOCKING EXAMPLE
		4304
		4305	Here is a fictitious example of how to run an event loop in a different
		4306	thread than where callbacks are being invoked and watchers are
		4307	created/added/removed.
		4308
		4309	For a real-world example, see the C<EV::Loop::Async> perl module,
		4310	which uses exactly this technique (which is suited for many high-level
		4311	languages).
		4312
		4313	The example uses a pthread mutex to protect the loop data, a condition
		4314	variable to wait for callback invocations, an async watcher to notify the
		4315	event loop thread and an unspecified mechanism to wake up the main thread.
		4316
		4317	First, you need to associate some data with the event loop:
		4318
		4319	typedef struct {
		4320	mutex_t lock; /* global loop lock */
		4321	ev_async async_w;
		4322	thread_t tid;
		4323	cond_t invoke_cv;
		4324	} userdata;
		4325
		4326	void prepare_loop (EV_P)
		4327	{
		4328	// for simplicity, we use a static userdata struct.
		4329	static userdata u;
		4330
		4331	ev_async_init (&u->async_w, async_cb);
		4332	ev_async_start (EV_A_ &u->async_w);
		4333
		4334	pthread_mutex_init (&u->lock, 0);
		4335	pthread_cond_init (&u->invoke_cv, 0);
		4336
		4337	// now associate this with the loop
		4338	ev_set_userdata (EV_A_ u);
		4339	ev_set_invoke_pending_cb (EV_A_ l_invoke);
		4340	ev_set_loop_release_cb (EV_A_ l_release, l_acquire);
		4341
		4342	// then create the thread running ev_loop
		4343	pthread_create (&u->tid, 0, l_run, EV_A);
		4344	}
		4345
		4346	The callback for the C<ev_async> watcher does nothing: the watcher is used
		4347	solely to wake up the event loop so it takes notice of any new watchers
		4348	that might have been added:
		4349
		4350	static void
		4351	async_cb (EV_P_ ev_async *w, int revents)
		4352	{
		4353	// just used for the side effects
		4354	}
		4355
		4356	The C<l_release> and C<l_acquire> callbacks simply unlock/lock the mutex
		4357	protecting the loop data, respectively.
		4358
		4359	static void
		4360	l_release (EV_P)
		4361	{
		4362	userdata *u = ev_userdata (EV_A);
		4363	pthread_mutex_unlock (&u->lock);
		4364	}
		4365
		4366	static void
		4367	l_acquire (EV_P)
		4368	{
		4369	userdata *u = ev_userdata (EV_A);
		4370	pthread_mutex_lock (&u->lock);
		4371	}
		4372
		4373	The event loop thread first acquires the mutex, and then jumps straight
		4374	into C<ev_run>:
		4375
		4376	void *
		4377	l_run (void *thr_arg)
		4378	{
		4379	struct ev_loop *loop = (struct ev_loop *)thr_arg;
		4380
		4381	l_acquire (EV_A);
		4382	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
		4383	ev_run (EV_A_ 0);
		4384	l_release (EV_A);
		4385
		4386	return 0;
		4387	}
		4388
		4389	Instead of invoking all pending watchers, the C<l_invoke> callback will
		4390	signal the main thread via some unspecified mechanism (signals? pipe
		4391	writes? C<Async::Interrupt>?) and then waits until all pending watchers
		4392	have been called (in a while loop because a) spurious wakeups are possible
		4393	and b) skipping inter-thread-communication when there are no pending
		4394	watchers is very beneficial):
		4395
		4396	static void
		4397	l_invoke (EV_P)
		4398	{
		4399	userdata *u = ev_userdata (EV_A);
		4400
		4401	while (ev_pending_count (EV_A))
		4402	{
		4403	wake_up_other_thread_in_some_magic_or_not_so_magic_way ();
		4404	pthread_cond_wait (&u->invoke_cv, &u->lock);
		4405	}
		4406	}
		4407
		4408	Now, whenever the main thread gets told to invoke pending watchers, it
		4409	will grab the lock, call C<ev_invoke_pending> and then signal the loop
		4410	thread to continue:
		4411
		4412	static void
		4413	real_invoke_pending (EV_P)
		4414	{
		4415	userdata *u = ev_userdata (EV_A);
		4416
		4417	pthread_mutex_lock (&u->lock);
		4418	ev_invoke_pending (EV_A);
		4419	pthread_cond_signal (&u->invoke_cv);
		4420	pthread_mutex_unlock (&u->lock);
		4421	}
		4422
		4423	Whenever you want to start/stop a watcher or do other modifications to an
		4424	event loop, you will now have to lock:
		4425
		4426	ev_timer timeout_watcher;
		4427	userdata *u = ev_userdata (EV_A);
		4428
		4429	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
		4430
		4431	pthread_mutex_lock (&u->lock);
		4432	ev_timer_start (EV_A_ &timeout_watcher);
		4433	ev_async_send (EV_A_ &u->async_w);
		4434	pthread_mutex_unlock (&u->lock);
		4435
		4436	Note that sending the C<ev_async> watcher is required because otherwise
		4437	an event loop currently blocking in the kernel will have no knowledge
		4438	about the newly added timer. By waking up the loop it will pick up any new
		4439	watchers in the next event loop iteration.
		4440
3858	=head3 COROUTINES	4441	=head3 COROUTINES
3859		4442
3860	Libev is very accommodating to coroutines ("cooperative threads"):	4443	Libev is very accommodating to coroutines ("cooperative threads"):
3861	libev fully supports nesting calls to its functions from different	4444	libev fully supports nesting calls to its functions from different
3862	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4445	coroutines (e.g. you can call C<ev_run> on the same loop from two
3863	different coroutines, and switch freely between both coroutines running the	4446	different coroutines, and switch freely between both coroutines running
3864	loop, as long as you don't confuse yourself). The only exception is that	4447	the loop, as long as you don't confuse yourself). The only exception is
3865	you must not do this from C<ev_periodic> reschedule callbacks.	4448	that you must not do this from C<ev_periodic> reschedule callbacks.
3866		4449
3867	Care has been taken to ensure that libev does not keep local state inside	4450	Care has been taken to ensure that libev does not keep local state inside
3868	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4451	C<ev_run>, and other calls do not usually allow for coroutine switches as
3869	they do not call any callbacks.	4452	they do not call any callbacks.
3870		4453
3871	=head2 COMPILER WARNINGS	4454	=head2 COMPILER WARNINGS
3872		4455
3873	Depending on your compiler and compiler settings, you might get no or a	4456	Depending on your compiler and compiler settings, you might get no or a
…		…
3884	maintainable.	4467	maintainable.
3885		4468
3886	And of course, some compiler warnings are just plain stupid, or simply	4469	And of course, some compiler warnings are just plain stupid, or simply
3887	wrong (because they don't actually warn about the condition their message	4470	wrong (because they don't actually warn about the condition their message
3888	seems to warn about). For example, certain older gcc versions had some	4471	seems to warn about). For example, certain older gcc versions had some
3889	warnings that resulted an extreme number of false positives. These have	4472	warnings that resulted in an extreme number of false positives. These have
3890	been fixed, but some people still insist on making code warn-free with	4473	been fixed, but some people still insist on making code warn-free with
3891	such buggy versions.	4474	such buggy versions.
3892		4475
3893	While libev is written to generate as few warnings as possible,	4476	While libev is written to generate as few warnings as possible,
3894	"warn-free" code is not a goal, and it is recommended not to build libev	4477	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
3930	I suggest using suppression lists.	4513	I suggest using suppression lists.
3931		4514
3932		4515
3933	=head1 PORTABILITY NOTES	4516	=head1 PORTABILITY NOTES
3934		4517
		4518	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4519
		4520	GNU/Linux is the only common platform that supports 64 bit file/large file
		4521	interfaces but I<disables> them by default.
		4522
		4523	That means that libev compiled in the default environment doesn't support
		4524	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4525
		4526	Unfortunately, many programs try to work around this GNU/Linux issue
		4527	by enabling the large file API, which makes them incompatible with the
		4528	standard libev compiled for their system.
		4529
		4530	Likewise, libev cannot enable the large file API itself as this would
		4531	suddenly make it incompatible to the default compile time environment,
		4532	i.e. all programs not using special compile switches.
		4533
		4534	=head2 OS/X AND DARWIN BUGS
		4535
		4536	The whole thing is a bug if you ask me - basically any system interface
		4537	you touch is broken, whether it is locales, poll, kqueue or even the
		4538	OpenGL drivers.
		4539
		4540	=head3 C<kqueue> is buggy
		4541
		4542	The kqueue syscall is broken in all known versions - most versions support
		4543	only sockets, many support pipes.
		4544
		4545	Libev tries to work around this by not using C<kqueue> by default on this
		4546	rotten platform, but of course you can still ask for it when creating a
		4547	loop - embedding a socket-only kqueue loop into a select-based one is
		4548	probably going to work well.
		4549
		4550	=head3 C<poll> is buggy
		4551
		4552	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4553	implementation by something calling C<kqueue> internally around the 10.5.6
		4554	release, so now C<kqueue> I<and> C<poll> are broken.
		4555
		4556	Libev tries to work around this by not using C<poll> by default on
		4557	this rotten platform, but of course you can still ask for it when creating
		4558	a loop.
		4559
		4560	=head3 C<select> is buggy
		4561
		4562	All that's left is C<select>, and of course Apple found a way to fuck this
		4563	one up as well: On OS/X, C<select> actively limits the number of file
		4564	descriptors you can pass in to 1024 - your program suddenly crashes when
		4565	you use more.
		4566
		4567	There is an undocumented "workaround" for this - defining
		4568	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4569	work on OS/X.
		4570
		4571	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4572
		4573	=head3 C<errno> reentrancy
		4574
		4575	The default compile environment on Solaris is unfortunately so
		4576	thread-unsafe that you can't even use components/libraries compiled
		4577	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4578	defined by default. A valid, if stupid, implementation choice.
		4579
		4580	If you want to use libev in threaded environments you have to make sure
		4581	it's compiled with C<_REENTRANT> defined.
		4582
		4583	=head3 Event port backend
		4584
		4585	The scalable event interface for Solaris is called "event
		4586	ports". Unfortunately, this mechanism is very buggy in all major
		4587	releases. If you run into high CPU usage, your program freezes or you get
		4588	a large number of spurious wakeups, make sure you have all the relevant
		4589	and latest kernel patches applied. No, I don't know which ones, but there
		4590	are multiple ones to apply, and afterwards, event ports actually work
		4591	great.
		4592
		4593	If you can't get it to work, you can try running the program by setting
		4594	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4595	C<select> backends.
		4596
		4597	=head2 AIX POLL BUG
		4598
		4599	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4600	this by trying to avoid the poll backend altogether (i.e. it's not even
		4601	compiled in), which normally isn't a big problem as C<select> works fine
		4602	with large bitsets on AIX, and AIX is dead anyway.
		4603
3935	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4604	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4605
		4606	=head3 General issues
3936		4607
3937	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4608	Win32 doesn't support any of the standards (e.g. POSIX) that libev
3938	requires, and its I/O model is fundamentally incompatible with the POSIX	4609	requires, and its I/O model is fundamentally incompatible with the POSIX
3939	model. Libev still offers limited functionality on this platform in	4610	model. Libev still offers limited functionality on this platform in
3940	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4611	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
3941	descriptors. This only applies when using Win32 natively, not when using	4612	descriptors. This only applies when using Win32 natively, not when using
3942	e.g. cygwin.	4613	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4614	as every compielr comes with a slightly differently broken/incompatible
		4615	environment.
3943		4616
3944	Lifting these limitations would basically require the full	4617	Lifting these limitations would basically require the full
3945	re-implementation of the I/O system. If you are into these kinds of	4618	re-implementation of the I/O system. If you are into this kind of thing,
3946	things, then note that glib does exactly that for you in a very portable	4619	then note that glib does exactly that for you in a very portable way (note
3947	way (note also that glib is the slowest event library known to man).	4620	also that glib is the slowest event library known to man).
3948		4621
3949	There is no supported compilation method available on windows except	4622	There is no supported compilation method available on windows except
3950	embedding it into other applications.	4623	embedding it into other applications.
3951		4624
3952	Sensible signal handling is officially unsupported by Microsoft - libev	4625	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
3980	you do I<not> compile the F<ev.c> or any other embedded source files!):	4653	you do I<not> compile the F<ev.c> or any other embedded source files!):
3981		4654
3982	#include "evwrap.h"	4655	#include "evwrap.h"
3983	#include "ev.c"	4656	#include "ev.c"
3984		4657
3985	=over 4
3986
3987	=item The winsocket select function	4658	=head3 The winsocket C<select> function
3988		4659
3989	The winsocket C<select> function doesn't follow POSIX in that it	4660	The winsocket C<select> function doesn't follow POSIX in that it
3990	requires socket I<handles> and not socket I<file descriptors> (it is	4661	requires socket I<handles> and not socket I<file descriptors> (it is
3991	also extremely buggy). This makes select very inefficient, and also	4662	also extremely buggy). This makes select very inefficient, and also
3992	requires a mapping from file descriptors to socket handles (the Microsoft	4663	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4001	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4672	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4002		4673
4003	Note that winsockets handling of fd sets is O(n), so you can easily get a	4674	Note that winsockets handling of fd sets is O(n), so you can easily get a
4004	complexity in the O(n²) range when using win32.	4675	complexity in the O(n²) range when using win32.
4005		4676
4006	=item Limited number of file descriptors	4677	=head3 Limited number of file descriptors
4007		4678
4008	Windows has numerous arbitrary (and low) limits on things.	4679	Windows has numerous arbitrary (and low) limits on things.
4009		4680
4010	Early versions of winsocket's select only supported waiting for a maximum	4681	Early versions of winsocket's select only supported waiting for a maximum
4011	of C<64> handles (probably owning to the fact that all windows kernels	4682	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4026	runtime libraries. This might get you to about C<512> or C<2048> sockets	4697	runtime libraries. This might get you to about C<512> or C<2048> sockets
4027	(depending on windows version and/or the phase of the moon). To get more,	4698	(depending on windows version and/or the phase of the moon). To get more,
4028	you need to wrap all I/O functions and provide your own fd management, but	4699	you need to wrap all I/O functions and provide your own fd management, but
4029	the cost of calling select (O(n²)) will likely make this unworkable.	4700	the cost of calling select (O(n²)) will likely make this unworkable.
4030		4701
4031	=back
4032
4033	=head2 PORTABILITY REQUIREMENTS	4702	=head2 PORTABILITY REQUIREMENTS
4034		4703
4035	In addition to a working ISO-C implementation and of course the	4704	In addition to a working ISO-C implementation and of course the
4036	backend-specific APIs, libev relies on a few additional extensions:	4705	backend-specific APIs, libev relies on a few additional extensions:
4037		4706
…		…
4075	watchers.	4744	watchers.
4076		4745
4077	=item C<double> must hold a time value in seconds with enough accuracy	4746	=item C<double> must hold a time value in seconds with enough accuracy
4078		4747
4079	The type C<double> is used to represent timestamps. It is required to	4748	The type C<double> is used to represent timestamps. It is required to
4080	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4749	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4081	enough for at least into the year 4000. This requirement is fulfilled by	4750	good enough for at least into the year 4000 with millisecond accuracy
		4751	(the design goal for libev). This requirement is overfulfilled by
4082	implementations implementing IEEE 754 (basically all existing ones).	4752	implementations using IEEE 754, which is basically all existing ones. With
		4753	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4083		4754
4084	=back	4755	=back
4085		4756
4086	If you know of other additional requirements drop me a note.	4757	If you know of other additional requirements drop me a note.
4087		4758
…		…
4155	involves iterating over all running async watchers or all signal numbers.	4826	involves iterating over all running async watchers or all signal numbers.
4156		4827
4157	=back	4828	=back
4158		4829
4159		4830
		4831	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4832
		4833	The major version 4 introduced some minor incompatible changes to the API.
		4834
		4835	At the moment, the C<ev.h> header file tries to implement superficial
		4836	compatibility, so most programs should still compile. Those might be
		4837	removed in later versions of libev, so better update early than late.
		4838
		4839	=over 4
		4840
		4841	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4842
		4843	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4844
		4845	ev_loop_destroy (EV_DEFAULT);
		4846	ev_loop_fork (EV_DEFAULT);
		4847
		4848	=item function/symbol renames
		4849
		4850	A number of functions and symbols have been renamed:
		4851
		4852	ev_loop => ev_run
		4853	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4854	EVLOOP_ONESHOT => EVRUN_ONCE
		4855
		4856	ev_unloop => ev_break
		4857	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4858	EVUNLOOP_ONE => EVBREAK_ONE
		4859	EVUNLOOP_ALL => EVBREAK_ALL
		4860
		4861	EV_TIMEOUT => EV_TIMER
		4862
		4863	ev_loop_count => ev_iteration
		4864	ev_loop_depth => ev_depth
		4865	ev_loop_verify => ev_verify
		4866
		4867	Most functions working on C<struct ev_loop> objects don't have an
		4868	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4869	associated constants have been renamed to not collide with the C<struct
		4870	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4871	as all other watcher types. Note that C<ev_loop_fork> is still called
		4872	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4873	typedef.
		4874
		4875	=item C<EV_COMPAT3> backwards compatibility mechanism
		4876
		4877	The backward compatibility mechanism can be controlled by
		4878	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4879	section.
		4880
		4881	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4882
		4883	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4884	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4885	and work, but the library code will of course be larger.
		4886
		4887	=back
		4888
		4889
4160	=head1 GLOSSARY	4890	=head1 GLOSSARY
4161		4891
4162	=over 4	4892	=over 4
4163		4893
4164	=item active	4894	=item active
4165		4895
4166	A watcher is active as long as it has been started (has been attached to	4896	A watcher is active as long as it has been started and not yet stopped.
4167	an event loop) but not yet stopped (disassociated from the event loop).	4897	See L<WATCHER STATES> for details.
4168		4898
4169	=item application	4899	=item application
4170		4900
4171	In this document, an application is whatever is using libev.	4901	In this document, an application is whatever is using libev.
		4902
		4903	=item backend
		4904
		4905	The part of the code dealing with the operating system interfaces.
4172		4906
4173	=item callback	4907	=item callback
4174		4908
4175	The address of a function that is called when some event has been	4909	The address of a function that is called when some event has been
4176	detected. Callbacks are being passed the event loop, the watcher that	4910	detected. Callbacks are being passed the event loop, the watcher that
4177	received the event, and the actual event bitset.	4911	received the event, and the actual event bitset.
4178		4912
4179	=item callback invocation	4913	=item callback/watcher invocation
4180		4914
4181	The act of calling the callback associated with a watcher.	4915	The act of calling the callback associated with a watcher.
4182		4916
4183	=item event	4917	=item event
4184		4918
4185	A change of state of some external event, such as data now being available	4919	A change of state of some external event, such as data now being available
4186	for reading on a file descriptor, time having passed or simply not having	4920	for reading on a file descriptor, time having passed or simply not having
4187	any other events happening anymore.	4921	any other events happening anymore.
4188		4922
4189	In libev, events are represented as single bits (such as C<EV_READ> or	4923	In libev, events are represented as single bits (such as C<EV_READ> or
4190	C<EV_TIMEOUT>).	4924	C<EV_TIMER>).
4191		4925
4192	=item event library	4926	=item event library
4193		4927
4194	A software package implementing an event model and loop.	4928	A software package implementing an event model and loop.
4195		4929
…		…
4203	The model used to describe how an event loop handles and processes	4937	The model used to describe how an event loop handles and processes
4204	watchers and events.	4938	watchers and events.
4205		4939
4206	=item pending	4940	=item pending
4207		4941
4208	A watcher is pending as soon as the corresponding event has been detected,	4942	A watcher is pending as soon as the corresponding event has been
4209	and stops being pending as soon as the watcher will be invoked or its	4943	detected. See L<WATCHER STATES> for details.
4210	pending status is explicitly cleared by the application.
4211
4212	A watcher can be pending, but not active. Stopping a watcher also clears
4213	its pending status.
4214		4944
4215	=item real time	4945	=item real time
4216		4946
4217	The physical time that is observed. It is apparently strictly monotonic :)	4947	The physical time that is observed. It is apparently strictly monotonic :)
4218		4948
…		…
4225	=item watcher	4955	=item watcher
4226		4956
4227	A data structure that describes interest in certain events. Watchers need	4957	A data structure that describes interest in certain events. Watchers need
4228	to be started (attached to an event loop) before they can receive events.	4958	to be started (attached to an event loop) before they can receive events.
4229		4959
4230	=item watcher invocation
4231
4232	The act of calling the callback associated with a watcher.
4233
4234	=back	4960	=back
4235		4961
4236	=head1 AUTHOR	4962	=head1 AUTHOR
4237		4963
4238	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4964	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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