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Revision 1.306 by root, Mon Oct 18 07:36:05 2010 UTC vs.
Revision 1.346 by root, Wed Nov 10 14:50:54 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
…		…
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	Familiarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
		82
		83	=head1 WHAT TO READ WHEN IN A HURRY
		84
		85	This manual tries to be very detailed, but unfortunately, this also makes
		86	it very long. If you just want to know the basics of libev, I suggest
		87	reading L<ANATOMY OF A WATCHER>, then the L<EXAMPLE PROGRAM> above and
		88	look up the missing functions in L<GLOBAL FUNCTIONS> and the C<ev_io> and
		89	C<ev_timer> sections in L<WATCHER TYPES>.
82		90
83	=head1 ABOUT LIBEV	91	=head1 ABOUT LIBEV
84		92
85	Libev is an event loop: you register interest in certain events (such as a	93	Libev is an event loop: you register interest in certain events (such as a
86	file descriptor being readable or a timeout occurring), and it will manage	94	file descriptor being readable or a timeout occurring), and it will manage
…		…
124	this argument.	132	this argument.
125		133
126	=head2 TIME REPRESENTATION	134	=head2 TIME REPRESENTATION
127		135
128	Libev represents time as a single floating point number, representing	136	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (in practise	137	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	somewhere near the beginning of 1970, details are complicated, don't	138	somewhere near the beginning of 1970, details are complicated, don't
131	ask). This type is called C<ev_tstamp>, which is what you should use	139	ask). This type is called C<ev_tstamp>, which is what you should use
132	too. It usually aliases to the C<double> type in C. When you need to do	140	too. It usually aliases to the C<double> type in C. When you need to do
133	any calculations on it, you should treat it as some floating point value.	141	any calculations on it, you should treat it as some floating point value.
134		142
…		…
165		173
166	=item ev_tstamp ev_time ()	174	=item ev_tstamp ev_time ()
167		175
168	Returns the current time as libev would use it. Please note that the	176	Returns the current time as libev would use it. Please note that the
169	C<ev_now> function is usually faster and also often returns the timestamp	177	C<ev_now> function is usually faster and also often returns the timestamp
170	you actually want to know.	178	you actually want to know. Also interesting is the combination of
		179	C<ev_update_now> and C<ev_now>.
171		180
172	=item ev_sleep (ev_tstamp interval)	181	=item ev_sleep (ev_tstamp interval)
173		182
174	Sleep for the given interval: The current thread will be blocked until	183	Sleep for the given interval: The current thread will be blocked until
175	either it is interrupted or the given time interval has passed. Basically	184	either it is interrupted or the given time interval has passed. Basically
…		…
192	as this indicates an incompatible change. Minor versions are usually	201	as this indicates an incompatible change. Minor versions are usually
193	compatible to older versions, so a larger minor version alone is usually	202	compatible to older versions, so a larger minor version alone is usually
194	not a problem.	203	not a problem.
195		204
196	Example: Make sure we haven't accidentally been linked against the wrong	205	Example: Make sure we haven't accidentally been linked against the wrong
197	version (note, however, that this will not detect ABI mismatches :).	206	version (note, however, that this will not detect other ABI mismatches,
		207	such as LFS or reentrancy).
198		208
199	assert (("libev version mismatch",	209	assert (("libev version mismatch",
200	ev_version_major () == EV_VERSION_MAJOR	210	ev_version_major () == EV_VERSION_MAJOR
201	&& ev_version_minor () >= EV_VERSION_MINOR));	211	&& ev_version_minor () >= EV_VERSION_MINOR));
202		212
…		…
213	assert (("sorry, no epoll, no sex",	223	assert (("sorry, no epoll, no sex",
214	ev_supported_backends () & EVBACKEND_EPOLL));	224	ev_supported_backends () & EVBACKEND_EPOLL));
215		225
216	=item unsigned int ev_recommended_backends ()	226	=item unsigned int ev_recommended_backends ()
217		227
218	Return the set of all backends compiled into this binary of libev and also	228	Return the set of all backends compiled into this binary of libev and
219	recommended for this platform. This set is often smaller than the one	229	also recommended for this platform, meaning it will work for most file
		230	descriptor types. This set is often smaller than the one returned by
220	returned by C<ev_supported_backends>, as for example kqueue is broken on	231	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
221	most BSDs and will not be auto-detected unless you explicitly request it	232	and will not be auto-detected unless you explicitly request it (assuming
222	(assuming you know what you are doing). This is the set of backends that	233	you know what you are doing). This is the set of backends that libev will
223	libev will probe for if you specify no backends explicitly.	234	probe for if you specify no backends explicitly.
224		235
225	=item unsigned int ev_embeddable_backends ()	236	=item unsigned int ev_embeddable_backends ()
226		237
227	Returns the set of backends that are embeddable in other event loops. This	238	Returns the set of backends that are embeddable in other event loops. This
228	is the theoretical, all-platform, value. To find which backends	239	value is platform-specific but can include backends not available on the
229	might be supported on the current system, you would need to look at	240	current system. To find which embeddable backends might be supported on
230	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	241	the current system, you would need to look at C<ev_embeddable_backends ()
231	recommended ones.	242	& ev_supported_backends ()>, likewise for recommended ones.
232		243
233	See the description of C<ev_embed> watchers for more info.	244	See the description of C<ev_embed> watchers for more info.
234		245
235	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]	246	=item ev_set_allocator (void *(*cb)(void *ptr, long size))
236		247
237	Sets the allocation function to use (the prototype is similar - the	248	Sets the allocation function to use (the prototype is similar - the
238	semantics are identical to the C<realloc> C89/SuS/POSIX function). It is	249	semantics are identical to the C<realloc> C89/SuS/POSIX function). It is
239	used to allocate and free memory (no surprises here). If it returns zero	250	used to allocate and free memory (no surprises here). If it returns zero
240	when memory needs to be allocated (C<size != 0>), the library might abort	251	when memory needs to be allocated (C<size != 0>), the library might abort
…		…
266	}	277	}
267		278
268	...	279	...
269	ev_set_allocator (persistent_realloc);	280	ev_set_allocator (persistent_realloc);
270		281
271	=item ev_set_syserr_cb (void (*cb)(const char *msg)); [NOT REENTRANT]	282	=item ev_set_syserr_cb (void (*cb)(const char *msg))
272		283
273	Set the callback function to call on a retryable system call error (such	284	Set the callback function to call on a retryable system call error (such
274	as failed select, poll, epoll_wait). The message is a printable string	285	as failed select, poll, epoll_wait). The message is a printable string
275	indicating the system call or subsystem causing the problem. If this	286	indicating the system call or subsystem causing the problem. If this
276	callback is set, then libev will expect it to remedy the situation, no	287	callback is set, then libev will expect it to remedy the situation, no
…		…
290	...	301	...
291	ev_set_syserr_cb (fatal_error);	302	ev_set_syserr_cb (fatal_error);
292		303
293	=back	304	=back
294		305
295	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	306	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
296		307
297	An event loop is described by a C<struct ev_loop *> (the C<struct>	308	An event loop is described by a C<struct ev_loop *> (the C<struct> is
298	is I<not> optional in this case, as there is also an C<ev_loop>	309	I<not> optional in this case unless libev 3 compatibility is disabled, as
299	I<function>).	310	libev 3 had an C<ev_loop> function colliding with the struct name).
300		311
301	The library knows two types of such loops, the I<default> loop, which	312	The library knows two types of such loops, the I<default> loop, which
302	supports signals and child events, and dynamically created loops which do	313	supports child process events, and dynamically created event loops which
303	not.	314	do not.
304		315
305	=over 4	316	=over 4
306		317
307	=item struct ev_loop *ev_default_loop (unsigned int flags)	318	=item struct ev_loop *ev_default_loop (unsigned int flags)
308		319
309	This will initialise the default event loop if it hasn't been initialised	320	This returns the "default" event loop object, which is what you should
310	yet and return it. If the default loop could not be initialised, returns	321	normally use when you just need "the event loop". Event loop objects and
311	false. If it already was initialised it simply returns it (and ignores the	322	the C<flags> parameter are described in more detail in the entry for
312	flags. If that is troubling you, check C<ev_backend ()> afterwards).	323	C<ev_loop_new>.
		324
		325	If the default loop is already initialised then this function simply
		326	returns it (and ignores the flags. If that is troubling you, check
		327	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		328	flags, which should almost always be C<0>, unless the caller is also the
		329	one calling C<ev_run> or otherwise qualifies as "the main program".
313		330
314	If you don't know what event loop to use, use the one returned from this	331	If you don't know what event loop to use, use the one returned from this
315	function.	332	function (or via the C<EV_DEFAULT> macro).
316		333
317	Note that this function is I<not> thread-safe, so if you want to use it	334	Note that this function is I<not> thread-safe, so if you want to use it
318	from multiple threads, you have to lock (note also that this is unlikely,	335	from multiple threads, you have to employ some kind of mutex (note also
319	as loops cannot be shared easily between threads anyway).	336	that this case is unlikely, as loops cannot be shared easily between
		337	threads anyway).
320		338
321	The default loop is the only loop that can handle C<ev_signal> and	339	The default loop is the only loop that can handle C<ev_child> watchers,
322	C<ev_child> watchers, and to do this, it always registers a handler	340	and to do this, it always registers a handler for C<SIGCHLD>. If this is
323	for C<SIGCHLD>. If this is a problem for your application you can either	341	a problem for your application you can either create a dynamic loop with
324	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	342	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
325	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	343	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
326	C<ev_default_init>.	344
		345	Example: This is the most typical usage.
		346
		347	if (!ev_default_loop (0))
		348	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		349
		350	Example: Restrict libev to the select and poll backends, and do not allow
		351	environment settings to be taken into account:
		352
		353	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
		354
		355	=item struct ev_loop *ev_loop_new (unsigned int flags)
		356
		357	This will create and initialise a new event loop object. If the loop
		358	could not be initialised, returns false.
		359
		360	This function is thread-safe, and one common way to use libev with
		361	threads is indeed to create one loop per thread, and using the default
		362	loop in the "main" or "initial" thread.
327		363
328	The flags argument can be used to specify special behaviour or specific	364	The flags argument can be used to specify special behaviour or specific
329	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	365	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
330		366
331	The following flags are supported:	367	The following flags are supported:
…		…
366	environment variable.	402	environment variable.
367		403
368	=item C<EVFLAG_NOINOTIFY>	404	=item C<EVFLAG_NOINOTIFY>
369		405
370	When this flag is specified, then libev will not attempt to use the	406	When this flag is specified, then libev will not attempt to use the
371	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and	407	I<inotify> API for its C<ev_stat> watchers. Apart from debugging and
372	testing, this flag can be useful to conserve inotify file descriptors, as	408	testing, this flag can be useful to conserve inotify file descriptors, as
373	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.	409	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
374		410
375	=item C<EVFLAG_SIGNALFD>	411	=item C<EVFLAG_SIGNALFD>
376		412
377	When this flag is specified, then libev will attempt to use the	413	When this flag is specified, then libev will attempt to use the
378	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API	414	I<signalfd> API for its C<ev_signal> (and C<ev_child>) watchers. This API
379	delivers signals synchronously, which makes it both faster and might make	415	delivers signals synchronously, which makes it both faster and might make
380	it possible to get the queued signal data. It can also simplify signal	416	it possible to get the queued signal data. It can also simplify signal
381	handling with threads, as long as you properly block signals in your	417	handling with threads, as long as you properly block signals in your
382	threads that are not interested in handling them.	418	threads that are not interested in handling them.
383		419
…		…
427	epoll scales either O(1) or O(active_fds).	463	epoll scales either O(1) or O(active_fds).
428		464
429	The epoll mechanism deserves honorable mention as the most misdesigned	465	The epoll mechanism deserves honorable mention as the most misdesigned
430	of the more advanced event mechanisms: mere annoyances include silently	466	of the more advanced event mechanisms: mere annoyances include silently
431	dropping file descriptors, requiring a system call per change per file	467	dropping file descriptors, requiring a system call per change per file
432	descriptor (and unnecessary guessing of parameters), problems with dup and	468	descriptor (and unnecessary guessing of parameters), problems with dup,
		469	returning before the timeout value, resulting in additional iterations
		470	(and only giving 5ms accuracy while select on the same platform gives
433	so on. The biggest issue is fork races, however - if a program forks then	471	0.1ms) and so on. The biggest issue is fork races, however - if a program
434	I<both> parent and child process have to recreate the epoll set, which can	472	forks then I<both> parent and child process have to recreate the epoll
435	take considerable time (one syscall per file descriptor) and is of course	473	set, which can take considerable time (one syscall per file descriptor)
436	hard to detect.	474	and is of course hard to detect.
437		475
438	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but	476	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but
439	of course I<doesn't>, and epoll just loves to report events for totally	477	of course I<doesn't>, and epoll just loves to report events for totally
440	I<different> file descriptors (even already closed ones, so one cannot	478	I<different> file descriptors (even already closed ones, so one cannot
441	even remove them from the set) than registered in the set (especially	479	even remove them from the set) than registered in the set (especially
…		…
443	employing an additional generation counter and comparing that against the	481	employing an additional generation counter and comparing that against the
444	events to filter out spurious ones, recreating the set when required. Last	482	events to filter out spurious ones, recreating the set when required. Last
445	not least, it also refuses to work with some file descriptors which work	483	not least, it also refuses to work with some file descriptors which work
446	perfectly fine with C<select> (files, many character devices...).	484	perfectly fine with C<select> (files, many character devices...).
447		485
		486	Epoll is truly the train wreck analog among event poll mechanisms.
		487
448	While stopping, setting and starting an I/O watcher in the same iteration	488	While stopping, setting and starting an I/O watcher in the same iteration
449	will result in some caching, there is still a system call per such	489	will result in some caching, there is still a system call per such
450	incident (because the same I<file descriptor> could point to a different	490	incident (because the same I<file descriptor> could point to a different
451	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	491	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
452	file descriptors might not work very well if you register events for both	492	file descriptors might not work very well if you register events for both
…		…
549	If one or more of the backend flags are or'ed into the flags value,	589	If one or more of the backend flags are or'ed into the flags value,
550	then only these backends will be tried (in the reverse order as listed	590	then only these backends will be tried (in the reverse order as listed
551	here). If none are specified, all backends in C<ev_recommended_backends	591	here). If none are specified, all backends in C<ev_recommended_backends
552	()> will be tried.	592	()> will be tried.
553		593
554	Example: This is the most typical usage.
555
556	if (!ev_default_loop (0))
557	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
558
559	Example: Restrict libev to the select and poll backends, and do not allow
560	environment settings to be taken into account:
561
562	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
563
564	Example: Use whatever libev has to offer, but make sure that kqueue is
565	used if available (warning, breaks stuff, best use only with your own
566	private event loop and only if you know the OS supports your types of
567	fds):
568
569	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
570
571	=item struct ev_loop *ev_loop_new (unsigned int flags)
572
573	Similar to C<ev_default_loop>, but always creates a new event loop that is
574	always distinct from the default loop.
575
576	Note that this function I<is> thread-safe, and one common way to use
577	libev with threads is indeed to create one loop per thread, and using the
578	default loop in the "main" or "initial" thread.
579
580	Example: Try to create a event loop that uses epoll and nothing else.	594	Example: Try to create a event loop that uses epoll and nothing else.
581		595
582	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	596	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
583	if (!epoller)	597	if (!epoller)
584	fatal ("no epoll found here, maybe it hides under your chair");	598	fatal ("no epoll found here, maybe it hides under your chair");
585		599
		600	Example: Use whatever libev has to offer, but make sure that kqueue is
		601	used if available.
		602
		603	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
		604
586	=item ev_default_destroy ()	605	=item ev_loop_destroy (loop)
587		606
588	Destroys the default loop (frees all memory and kernel state etc.). None	607	Destroys an event loop object (frees all memory and kernel state
589	of the active event watchers will be stopped in the normal sense, so	608	etc.). None of the active event watchers will be stopped in the normal
590	e.g. C<ev_is_active> might still return true. It is your responsibility to	609	sense, so e.g. C<ev_is_active> might still return true. It is your
591	either stop all watchers cleanly yourself I<before> calling this function,	610	responsibility to either stop all watchers cleanly yourself I<before>
592	or cope with the fact afterwards (which is usually the easiest thing, you	611	calling this function, or cope with the fact afterwards (which is usually
593	can just ignore the watchers and/or C<free ()> them for example).	612	the easiest thing, you can just ignore the watchers and/or C<free ()> them
		613	for example).
594		614
595	Note that certain global state, such as signal state (and installed signal	615	Note that certain global state, such as signal state (and installed signal
596	handlers), will not be freed by this function, and related watchers (such	616	handlers), will not be freed by this function, and related watchers (such
597	as signal and child watchers) would need to be stopped manually.	617	as signal and child watchers) would need to be stopped manually.
598		618
599	In general it is not advisable to call this function except in the	619	This function is normally used on loop objects allocated by
600	rare occasion where you really need to free e.g. the signal handling	620	C<ev_loop_new>, but it can also be used on the default loop returned by
		621	C<ev_default_loop>, in which case it is not thread-safe.
		622
		623	Note that it is not advisable to call this function on the default loop
		624	except in the rare occasion where you really need to free its resources.
601	pipe fds. If you need dynamically allocated loops it is better to use	625	If you need dynamically allocated loops it is better to use C<ev_loop_new>
602	C<ev_loop_new> and C<ev_loop_destroy>.	626	and C<ev_loop_destroy>.
603		627
604	=item ev_loop_destroy (loop)	628	=item ev_loop_fork (loop)
605		629
606	Like C<ev_default_destroy>, but destroys an event loop created by an
607	earlier call to C<ev_loop_new>.
608
609	=item ev_default_fork ()
610
611	This function sets a flag that causes subsequent C<ev_loop> iterations	630	This function sets a flag that causes subsequent C<ev_run> iterations to
612	to reinitialise the kernel state for backends that have one. Despite the	631	reinitialise the kernel state for backends that have one. Despite the
613	name, you can call it anytime, but it makes most sense after forking, in	632	name, you can call it anytime, but it makes most sense after forking, in
614	the child process (or both child and parent, but that again makes little	633	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
615	sense). You I<must> call it in the child before using any of the libev	634	child before resuming or calling C<ev_run>.
616	functions, and it will only take effect at the next C<ev_loop> iteration.
617		635
618	Again, you I<have> to call it on I<any> loop that you want to re-use after	636	Again, you I<have> to call it on I<any> loop that you want to re-use after
619	a fork, I<even if you do not plan to use the loop in the parent>. This is	637	a fork, I<even if you do not plan to use the loop in the parent>. This is
620	because some kernel interfaces *cough* I<kqueue> *cough* do funny things	638	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
621	during fork.	639	during fork.
622		640
623	On the other hand, you only need to call this function in the child	641	On the other hand, you only need to call this function in the child
624	process if and only if you want to use the event loop in the child. If you	642	process if and only if you want to use the event loop in the child. If
625	just fork+exec or create a new loop in the child, you don't have to call	643	you just fork+exec or create a new loop in the child, you don't have to
626	it at all.	644	call it at all (in fact, C<epoll> is so badly broken that it makes a
		645	difference, but libev will usually detect this case on its own and do a
		646	costly reset of the backend).
627		647
628	The function itself is quite fast and it's usually not a problem to call	648	The function itself is quite fast and it's usually not a problem to call
629	it just in case after a fork. To make this easy, the function will fit in	649	it just in case after a fork.
630	quite nicely into a call to C<pthread_atfork>:
631		650
		651	Example: Automate calling C<ev_loop_fork> on the default loop when
		652	using pthreads.
		653
		654	static void
		655	post_fork_child (void)
		656	{
		657	ev_loop_fork (EV_DEFAULT);
		658	}
		659
		660	...
632	pthread_atfork (0, 0, ev_default_fork);	661	pthread_atfork (0, 0, post_fork_child);
633
634	=item ev_loop_fork (loop)
635
636	Like C<ev_default_fork>, but acts on an event loop created by
637	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
638	after fork that you want to re-use in the child, and how you keep track of
639	them is entirely your own problem.
640		662
641	=item int ev_is_default_loop (loop)	663	=item int ev_is_default_loop (loop)
642		664
643	Returns true when the given loop is, in fact, the default loop, and false	665	Returns true when the given loop is, in fact, the default loop, and false
644	otherwise.	666	otherwise.
645		667
646	=item unsigned int ev_iteration (loop)	668	=item unsigned int ev_iteration (loop)
647		669
648	Returns the current iteration count for the loop, which is identical to	670	Returns the current iteration count for the event loop, which is identical
649	the number of times libev did poll for new events. It starts at C<0> and	671	to the number of times libev did poll for new events. It starts at C<0>
650	happily wraps around with enough iterations.	672	and happily wraps around with enough iterations.
651		673
652	This value can sometimes be useful as a generation counter of sorts (it	674	This value can sometimes be useful as a generation counter of sorts (it
653	"ticks" the number of loop iterations), as it roughly corresponds with	675	"ticks" the number of loop iterations), as it roughly corresponds with
654	C<ev_prepare> and C<ev_check> calls - and is incremented between the	676	C<ev_prepare> and C<ev_check> calls - and is incremented between the
655	prepare and check phases.	677	prepare and check phases.
656		678
657	=item unsigned int ev_depth (loop)	679	=item unsigned int ev_depth (loop)
658		680
659	Returns the number of times C<ev_loop> was entered minus the number of	681	Returns the number of times C<ev_run> was entered minus the number of
660	times C<ev_loop> was exited, in other words, the recursion depth.	682	times C<ev_run> was exited normally, in other words, the recursion depth.
661		683
662	Outside C<ev_loop>, this number is zero. In a callback, this number is	684	Outside C<ev_run>, this number is zero. In a callback, this number is
663	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	685	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
664	in which case it is higher.	686	in which case it is higher.
665		687
666	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	688	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread,
667	etc.), doesn't count as "exit" - consider this as a hint to avoid such	689	throwing an exception etc.), doesn't count as "exit" - consider this
668	ungentleman behaviour unless it's really convenient.	690	as a hint to avoid such ungentleman-like behaviour unless it's really
		691	convenient, in which case it is fully supported.
669		692
670	=item unsigned int ev_backend (loop)	693	=item unsigned int ev_backend (loop)
671		694
672	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	695	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
673	use.	696	use.
…		…
682		705
683	=item ev_now_update (loop)	706	=item ev_now_update (loop)
684		707
685	Establishes the current time by querying the kernel, updating the time	708	Establishes the current time by querying the kernel, updating the time
686	returned by C<ev_now ()> in the progress. This is a costly operation and	709	returned by C<ev_now ()> in the progress. This is a costly operation and
687	is usually done automatically within C<ev_loop ()>.	710	is usually done automatically within C<ev_run ()>.
688		711
689	This function is rarely useful, but when some event callback runs for a	712	This function is rarely useful, but when some event callback runs for a
690	very long time without entering the event loop, updating libev's idea of	713	very long time without entering the event loop, updating libev's idea of
691	the current time is a good idea.	714	the current time is a good idea.
692		715
…		…
694		717
695	=item ev_suspend (loop)	718	=item ev_suspend (loop)
696		719
697	=item ev_resume (loop)	720	=item ev_resume (loop)
698		721
699	These two functions suspend and resume a loop, for use when the loop is	722	These two functions suspend and resume an event loop, for use when the
700	not used for a while and timeouts should not be processed.	723	loop is not used for a while and timeouts should not be processed.
701		724
702	A typical use case would be an interactive program such as a game: When	725	A typical use case would be an interactive program such as a game: When
703	the user presses C<^Z> to suspend the game and resumes it an hour later it	726	the user presses C<^Z> to suspend the game and resumes it an hour later it
704	would be best to handle timeouts as if no time had actually passed while	727	would be best to handle timeouts as if no time had actually passed while
705	the program was suspended. This can be achieved by calling C<ev_suspend>	728	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
716	without a previous call to C<ev_suspend>.	739	without a previous call to C<ev_suspend>.
717		740
718	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	741	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
719	event loop time (see C<ev_now_update>).	742	event loop time (see C<ev_now_update>).
720		743
721	=item ev_loop (loop, int flags)	744	=item ev_run (loop, int flags)
722		745
723	Finally, this is it, the event handler. This function usually is called	746	Finally, this is it, the event handler. This function usually is called
724	after you have initialised all your watchers and you want to start	747	after you have initialised all your watchers and you want to start
725	handling events.	748	handling events. It will ask the operating system for any new events, call
		749	the watcher callbacks, an then repeat the whole process indefinitely: This
		750	is why event loops are called I<loops>.
726		751
727	If the flags argument is specified as C<0>, it will not return until	752	If the flags argument is specified as C<0>, it will keep handling events
728	either no event watchers are active anymore or C<ev_unloop> was called.	753	until either no event watchers are active anymore or C<ev_break> was
		754	called.
729		755
730	Please note that an explicit C<ev_unloop> is usually better than	756	Please note that an explicit C<ev_break> is usually better than
731	relying on all watchers to be stopped when deciding when a program has	757	relying on all watchers to be stopped when deciding when a program has
732	finished (especially in interactive programs), but having a program	758	finished (especially in interactive programs), but having a program
733	that automatically loops as long as it has to and no longer by virtue	759	that automatically loops as long as it has to and no longer by virtue
734	of relying on its watchers stopping correctly, that is truly a thing of	760	of relying on its watchers stopping correctly, that is truly a thing of
735	beauty.	761	beauty.
736		762
		763	This function is also I<mostly> exception-safe - you can break out of
		764	a C<ev_run> call by calling C<longjmp> in a callback, throwing a C++
		765	exception and so on. This does not decrement the C<ev_depth> value, nor
		766	will it clear any outstanding C<EVBREAK_ONE> breaks.
		767
737	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	768	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
738	those events and any already outstanding ones, but will not block your	769	those events and any already outstanding ones, but will not wait and
739	process in case there are no events and will return after one iteration of	770	block your process in case there are no events and will return after one
740	the loop.	771	iteration of the loop. This is sometimes useful to poll and handle new
		772	events while doing lengthy calculations, to keep the program responsive.
741		773
742	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	774	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
743	necessary) and will handle those and any already outstanding ones. It	775	necessary) and will handle those and any already outstanding ones. It
744	will block your process until at least one new event arrives (which could	776	will block your process until at least one new event arrives (which could
745	be an event internal to libev itself, so there is no guarantee that a	777	be an event internal to libev itself, so there is no guarantee that a
746	user-registered callback will be called), and will return after one	778	user-registered callback will be called), and will return after one
747	iteration of the loop.	779	iteration of the loop.
748		780
749	This is useful if you are waiting for some external event in conjunction	781	This is useful if you are waiting for some external event in conjunction
750	with something not expressible using other libev watchers (i.e. "roll your	782	with something not expressible using other libev watchers (i.e. "roll your
751	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	783	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
752	usually a better approach for this kind of thing.	784	usually a better approach for this kind of thing.
753		785
754	Here are the gory details of what C<ev_loop> does:	786	Here are the gory details of what C<ev_run> does:
755		787
		788	- Increment loop depth.
		789	- Reset the ev_break status.
756	- Before the first iteration, call any pending watchers.	790	- Before the first iteration, call any pending watchers.
		791	LOOP:
757	* If EVFLAG_FORKCHECK was used, check for a fork.	792	- If EVFLAG_FORKCHECK was used, check for a fork.
758	- If a fork was detected (by any means), queue and call all fork watchers.	793	- If a fork was detected (by any means), queue and call all fork watchers.
759	- Queue and call all prepare watchers.	794	- Queue and call all prepare watchers.
		795	- If ev_break was called, goto FINISH.
760	- If we have been forked, detach and recreate the kernel state	796	- If we have been forked, detach and recreate the kernel state
761	as to not disturb the other process.	797	as to not disturb the other process.
762	- Update the kernel state with all outstanding changes.	798	- Update the kernel state with all outstanding changes.
763	- Update the "event loop time" (ev_now ()).	799	- Update the "event loop time" (ev_now ()).
764	- Calculate for how long to sleep or block, if at all	800	- Calculate for how long to sleep or block, if at all
765	(active idle watchers, EVLOOP_NONBLOCK or not having	801	(active idle watchers, EVRUN_NOWAIT or not having
766	any active watchers at all will result in not sleeping).	802	any active watchers at all will result in not sleeping).
767	- Sleep if the I/O and timer collect interval say so.	803	- Sleep if the I/O and timer collect interval say so.
		804	- Increment loop iteration counter.
768	- Block the process, waiting for any events.	805	- Block the process, waiting for any events.
769	- Queue all outstanding I/O (fd) events.	806	- Queue all outstanding I/O (fd) events.
770	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	807	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
771	- Queue all expired timers.	808	- Queue all expired timers.
772	- Queue all expired periodics.	809	- Queue all expired periodics.
773	- Unless any events are pending now, queue all idle watchers.	810	- Queue all idle watchers with priority higher than that of pending events.
774	- Queue all check watchers.	811	- Queue all check watchers.
775	- Call all queued watchers in reverse order (i.e. check watchers first).	812	- Call all queued watchers in reverse order (i.e. check watchers first).
776	Signals and child watchers are implemented as I/O watchers, and will	813	Signals and child watchers are implemented as I/O watchers, and will
777	be handled here by queueing them when their watcher gets executed.	814	be handled here by queueing them when their watcher gets executed.
778	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	815	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
779	were used, or there are no active watchers, return, otherwise	816	were used, or there are no active watchers, goto FINISH, otherwise
780	continue with step *.	817	continue with step LOOP.
		818	FINISH:
		819	- Reset the ev_break status iff it was EVBREAK_ONE.
		820	- Decrement the loop depth.
		821	- Return.
781		822
782	Example: Queue some jobs and then loop until no events are outstanding	823	Example: Queue some jobs and then loop until no events are outstanding
783	anymore.	824	anymore.
784		825
785	... queue jobs here, make sure they register event watchers as long	826	... queue jobs here, make sure they register event watchers as long
786	... as they still have work to do (even an idle watcher will do..)	827	... as they still have work to do (even an idle watcher will do..)
787	ev_loop (my_loop, 0);	828	ev_run (my_loop, 0);
788	... jobs done or somebody called unloop. yeah!	829	... jobs done or somebody called unloop. yeah!
789		830
790	=item ev_unloop (loop, how)	831	=item ev_break (loop, how)
791		832
792	Can be used to make a call to C<ev_loop> return early (but only after it	833	Can be used to make a call to C<ev_run> return early (but only after it
793	has processed all outstanding events). The C<how> argument must be either	834	has processed all outstanding events). The C<how> argument must be either
794	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	835	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
795	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	836	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
796		837
797	This "unloop state" will be cleared when entering C<ev_loop> again.	838	This "break state" will be cleared on the next call to C<ev_run>.
798		839
799	It is safe to call C<ev_unloop> from outside any C<ev_loop> calls.	840	It is safe to call C<ev_break> from outside any C<ev_run> calls, too, in
		841	which case it will have no effect.
800		842
801	=item ev_ref (loop)	843	=item ev_ref (loop)
802		844
803	=item ev_unref (loop)	845	=item ev_unref (loop)
804		846
805	Ref/unref can be used to add or remove a reference count on the event	847	Ref/unref can be used to add or remove a reference count on the event
806	loop: Every watcher keeps one reference, and as long as the reference	848	loop: Every watcher keeps one reference, and as long as the reference
807	count is nonzero, C<ev_loop> will not return on its own.	849	count is nonzero, C<ev_run> will not return on its own.
808		850
809	This is useful when you have a watcher that you never intend to	851	This is useful when you have a watcher that you never intend to
810	unregister, but that nevertheless should not keep C<ev_loop> from	852	unregister, but that nevertheless should not keep C<ev_run> from
811	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>	853	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
812	before stopping it.	854	before stopping it.
813		855
814	As an example, libev itself uses this for its internal signal pipe: It	856	As an example, libev itself uses this for its internal signal pipe: It
815	is not visible to the libev user and should not keep C<ev_loop> from	857	is not visible to the libev user and should not keep C<ev_run> from
816	exiting if no event watchers registered by it are active. It is also an	858	exiting if no event watchers registered by it are active. It is also an
817	excellent way to do this for generic recurring timers or from within	859	excellent way to do this for generic recurring timers or from within
818	third-party libraries. Just remember to I<unref after start> and I<ref	860	third-party libraries. Just remember to I<unref after start> and I<ref
819	before stop> (but only if the watcher wasn't active before, or was active	861	before stop> (but only if the watcher wasn't active before, or was active
820	before, respectively. Note also that libev might stop watchers itself	862	before, respectively. Note also that libev might stop watchers itself
821	(e.g. non-repeating timers) in which case you have to C<ev_ref>	863	(e.g. non-repeating timers) in which case you have to C<ev_ref>
822	in the callback).	864	in the callback).
823		865
824	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	866	Example: Create a signal watcher, but keep it from keeping C<ev_run>
825	running when nothing else is active.	867	running when nothing else is active.
826		868
827	ev_signal exitsig;	869	ev_signal exitsig;
828	ev_signal_init (&exitsig, sig_cb, SIGINT);	870	ev_signal_init (&exitsig, sig_cb, SIGINT);
829	ev_signal_start (loop, &exitsig);	871	ev_signal_start (loop, &exitsig);
…		…
892	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	934	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
893		935
894	=item ev_invoke_pending (loop)	936	=item ev_invoke_pending (loop)
895		937
896	This call will simply invoke all pending watchers while resetting their	938	This call will simply invoke all pending watchers while resetting their
897	pending state. Normally, C<ev_loop> does this automatically when required,	939	pending state. Normally, C<ev_run> does this automatically when required,
898	but when overriding the invoke callback this call comes handy.	940	but when overriding the invoke callback this call comes handy. This
		941	function can be invoked from a watcher - this can be useful for example
		942	when you want to do some lengthy calculation and want to pass further
		943	event handling to another thread (you still have to make sure only one
		944	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
899		945
900	=item int ev_pending_count (loop)	946	=item int ev_pending_count (loop)
901		947
902	Returns the number of pending watchers - zero indicates that no watchers	948	Returns the number of pending watchers - zero indicates that no watchers
903	are pending.	949	are pending.
904		950
905	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	951	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
906		952
907	This overrides the invoke pending functionality of the loop: Instead of	953	This overrides the invoke pending functionality of the loop: Instead of
908	invoking all pending watchers when there are any, C<ev_loop> will call	954	invoking all pending watchers when there are any, C<ev_run> will call
909	this callback instead. This is useful, for example, when you want to	955	this callback instead. This is useful, for example, when you want to
910	invoke the actual watchers inside another context (another thread etc.).	956	invoke the actual watchers inside another context (another thread etc.).
911		957
912	If you want to reset the callback, use C<ev_invoke_pending> as new	958	If you want to reset the callback, use C<ev_invoke_pending> as new
913	callback.	959	callback.
…		…
916		962
917	Sometimes you want to share the same loop between multiple threads. This	963	Sometimes you want to share the same loop between multiple threads. This
918	can be done relatively simply by putting mutex_lock/unlock calls around	964	can be done relatively simply by putting mutex_lock/unlock calls around
919	each call to a libev function.	965	each call to a libev function.
920		966
921	However, C<ev_loop> can run an indefinite time, so it is not feasible to	967	However, C<ev_run> can run an indefinite time, so it is not feasible
922	wait for it to return. One way around this is to wake up the loop via	968	to wait for it to return. One way around this is to wake up the event
923	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	969	loop via C<ev_break> and C<av_async_send>, another way is to set these
924	and I<acquire> callbacks on the loop.	970	I<release> and I<acquire> callbacks on the loop.
925		971
926	When set, then C<release> will be called just before the thread is	972	When set, then C<release> will be called just before the thread is
927	suspended waiting for new events, and C<acquire> is called just	973	suspended waiting for new events, and C<acquire> is called just
928	afterwards.	974	afterwards.
929		975
…		…
932		978
933	While event loop modifications are allowed between invocations of	979	While event loop modifications are allowed between invocations of
934	C<release> and C<acquire> (that's their only purpose after all), no	980	C<release> and C<acquire> (that's their only purpose after all), no
935	modifications done will affect the event loop, i.e. adding watchers will	981	modifications done will affect the event loop, i.e. adding watchers will
936	have no effect on the set of file descriptors being watched, or the time	982	have no effect on the set of file descriptors being watched, or the time
937	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	983	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
938	to take note of any changes you made.	984	to take note of any changes you made.
939		985
940	In theory, threads executing C<ev_loop> will be async-cancel safe between	986	In theory, threads executing C<ev_run> will be async-cancel safe between
941	invocations of C<release> and C<acquire>.	987	invocations of C<release> and C<acquire>.
942		988
943	See also the locking example in the C<THREADS> section later in this	989	See also the locking example in the C<THREADS> section later in this
944	document.	990	document.
945		991
946	=item ev_set_userdata (loop, void *data)	992	=item ev_set_userdata (loop, void *data)
947		993
948	=item ev_userdata (loop)	994	=item void *ev_userdata (loop)
949		995
950	Set and retrieve a single C<void *> associated with a loop. When	996	Set and retrieve a single C<void *> associated with a loop. When
951	C<ev_set_userdata> has never been called, then C<ev_userdata> returns	997	C<ev_set_userdata> has never been called, then C<ev_userdata> returns
952	C<0.>	998	C<0>.
953		999
954	These two functions can be used to associate arbitrary data with a loop,	1000	These two functions can be used to associate arbitrary data with a loop,
955	and are intended solely for the C<invoke_pending_cb>, C<release> and	1001	and are intended solely for the C<invoke_pending_cb>, C<release> and
956	C<acquire> callbacks described above, but of course can be (ab-)used for	1002	C<acquire> callbacks described above, but of course can be (ab-)used for
957	any other purpose as well.	1003	any other purpose as well.
958		1004
959	=item ev_loop_verify (loop)	1005	=item ev_verify (loop)
960		1006
961	This function only does something when C<EV_VERIFY> support has been	1007	This function only does something when C<EV_VERIFY> support has been
962	compiled in, which is the default for non-minimal builds. It tries to go	1008	compiled in, which is the default for non-minimal builds. It tries to go
963	through all internal structures and checks them for validity. If anything	1009	through all internal structures and checks them for validity. If anything
964	is found to be inconsistent, it will print an error message to standard	1010	is found to be inconsistent, it will print an error message to standard
…		…
975		1021
976	In the following description, uppercase C<TYPE> in names stands for the	1022	In the following description, uppercase C<TYPE> in names stands for the
977	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1023	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
978	watchers and C<ev_io_start> for I/O watchers.	1024	watchers and C<ev_io_start> for I/O watchers.
979		1025
980	A watcher is a structure that you create and register to record your	1026	A watcher is an opaque structure that you allocate and register to record
981	interest in some event. For instance, if you want to wait for STDIN to	1027	your interest in some event. To make a concrete example, imagine you want
982	become readable, you would create an C<ev_io> watcher for that:	1028	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1029	for that:
983		1030
984	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1031	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
985	{	1032	{
986	ev_io_stop (w);	1033	ev_io_stop (w);
987	ev_unloop (loop, EVUNLOOP_ALL);	1034	ev_break (loop, EVBREAK_ALL);
988	}	1035	}
989		1036
990	struct ev_loop *loop = ev_default_loop (0);	1037	struct ev_loop *loop = ev_default_loop (0);
991		1038
992	ev_io stdin_watcher;	1039	ev_io stdin_watcher;
993		1040
994	ev_init (&stdin_watcher, my_cb);	1041	ev_init (&stdin_watcher, my_cb);
995	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1042	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
996	ev_io_start (loop, &stdin_watcher);	1043	ev_io_start (loop, &stdin_watcher);
997		1044
998	ev_loop (loop, 0);	1045	ev_run (loop, 0);
999		1046
1000	As you can see, you are responsible for allocating the memory for your	1047	As you can see, you are responsible for allocating the memory for your
1001	watcher structures (and it is I<usually> a bad idea to do this on the	1048	watcher structures (and it is I<usually> a bad idea to do this on the
1002	stack).	1049	stack).
1003		1050
1004	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1051	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1005	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1052	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1006		1053
1007	Each watcher structure must be initialised by a call to C<ev_init	1054	Each watcher structure must be initialised by a call to C<ev_init (watcher
1008	(watcher *, callback)>, which expects a callback to be provided. This	1055	*, callback)>, which expects a callback to be provided. This callback is
1009	callback gets invoked each time the event occurs (or, in the case of I/O	1056	invoked each time the event occurs (or, in the case of I/O watchers, each
1010	watchers, each time the event loop detects that the file descriptor given	1057	time the event loop detects that the file descriptor given is readable
1011	is readable and/or writable).	1058	and/or writable).
1012		1059
1013	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1060	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1014	macro to configure it, with arguments specific to the watcher type. There	1061	macro to configure it, with arguments specific to the watcher type. There
1015	is also a macro to combine initialisation and setting in one call: C<<	1062	is also a macro to combine initialisation and setting in one call: C<<
1016	ev_TYPE_init (watcher *, callback, ...) >>.	1063	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1067		1114
1068	=item C<EV_PREPARE>	1115	=item C<EV_PREPARE>
1069		1116
1070	=item C<EV_CHECK>	1117	=item C<EV_CHECK>
1071		1118
1072	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1119	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1073	to gather new events, and all C<ev_check> watchers are invoked just after	1120	to gather new events, and all C<ev_check> watchers are invoked just after
1074	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1121	C<ev_run> has gathered them, but before it invokes any callbacks for any
1075	received events. Callbacks of both watcher types can start and stop as	1122	received events. Callbacks of both watcher types can start and stop as
1076	many watchers as they want, and all of them will be taken into account	1123	many watchers as they want, and all of them will be taken into account
1077	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1124	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1078	C<ev_loop> from blocking).	1125	C<ev_run> from blocking).
1079		1126
1080	=item C<EV_EMBED>	1127	=item C<EV_EMBED>
1081		1128
1082	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1129	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1083		1130
1084	=item C<EV_FORK>	1131	=item C<EV_FORK>
1085		1132
1086	The event loop has been resumed in the child process after fork (see	1133	The event loop has been resumed in the child process after fork (see
1087	C<ev_fork>).	1134	C<ev_fork>).
		1135
		1136	=item C<EV_CLEANUP>
		1137
		1138	The event loop is about to be destroyed (see C<ev_cleanup>).
1088		1139
1089	=item C<EV_ASYNC>	1140	=item C<EV_ASYNC>
1090		1141
1091	The given async watcher has been asynchronously notified (see C<ev_async>).	1142	The given async watcher has been asynchronously notified (see C<ev_async>).
1092		1143
…		…
1264		1315
1265	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related	1316	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
1266	functions that do not need a watcher.	1317	functions that do not need a watcher.
1267		1318
1268	=back	1319	=back
1269
1270		1320
1271	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1321	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
1272		1322
1273	Each watcher has, by default, a member C<void *data> that you can change	1323	Each watcher has, by default, a member C<void *data> that you can change
1274	and read at any time: libev will completely ignore it. This can be used	1324	and read at any time: libev will completely ignore it. This can be used
…		…
1330	t2_cb (EV_P_ ev_timer *w, int revents)	1380	t2_cb (EV_P_ ev_timer *w, int revents)
1331	{	1381	{
1332	struct my_biggy big = (struct my_biggy *)	1382	struct my_biggy big = (struct my_biggy *)
1333	(((char *)w) - offsetof (struct my_biggy, t2));	1383	(((char *)w) - offsetof (struct my_biggy, t2));
1334	}	1384	}
		1385
		1386	=head2 WATCHER STATES
		1387
		1388	There are various watcher states mentioned throughout this manual -
		1389	active, pending and so on. In this section these states and the rules to
		1390	transition between them will be described in more detail - and while these
		1391	rules might look complicated, they usually do "the right thing".
		1392
		1393	=over 4
		1394
		1395	=item initialiased
		1396
		1397	Before a watcher can be registered with the event looop it has to be
		1398	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1399	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1400
		1401	In this state it is simply some block of memory that is suitable for use
		1402	in an event loop. It can be moved around, freed, reused etc. at will.
		1403
		1404	=item started/running/active
		1405
		1406	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1407	property of the event loop, and is actively waiting for events. While in
		1408	this state it cannot be accessed (except in a few documented ways), moved,
		1409	freed or anything else - the only legal thing is to keep a pointer to it,
		1410	and call libev functions on it that are documented to work on active watchers.
		1411
		1412	=item pending
		1413
		1414	If a watcher is active and libev determines that an event it is interested
		1415	in has occurred (such as a timer expiring), it will become pending. It will
		1416	stay in this pending state until either it is stopped or its callback is
		1417	about to be invoked, so it is not normally pending inside the watcher
		1418	callback.
		1419
		1420	The watcher might or might not be active while it is pending (for example,
		1421	an expired non-repeating timer can be pending but no longer active). If it
		1422	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1423	but it is still property of the event loop at this time, so cannot be
		1424	moved, freed or reused. And if it is active the rules described in the
		1425	previous item still apply.
		1426
		1427	It is also possible to feed an event on a watcher that is not active (e.g.
		1428	via C<ev_feed_event>), in which case it becomes pending without being
		1429	active.
		1430
		1431	=item stopped
		1432
		1433	A watcher can be stopped implicitly by libev (in which case it might still
		1434	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1435	latter will clear any pending state the watcher might be in, regardless
		1436	of whether it was active or not, so stopping a watcher explicitly before
		1437	freeing it is often a good idea.
		1438
		1439	While stopped (and not pending) the watcher is essentially in the
		1440	initialised state, that is it can be reused, moved, modified in any way
		1441	you wish.
		1442
		1443	=back
1335		1444
1336	=head2 WATCHER PRIORITY MODELS	1445	=head2 WATCHER PRIORITY MODELS
1337		1446
1338	Many event loops support I<watcher priorities>, which are usually small	1447	Many event loops support I<watcher priorities>, which are usually small
1339	integers that influence the ordering of event callback invocation	1448	integers that influence the ordering of event callback invocation
…		…
1624	...	1733	...
1625	struct ev_loop *loop = ev_default_init (0);	1734	struct ev_loop *loop = ev_default_init (0);
1626	ev_io stdin_readable;	1735	ev_io stdin_readable;
1627	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1736	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1628	ev_io_start (loop, &stdin_readable);	1737	ev_io_start (loop, &stdin_readable);
1629	ev_loop (loop, 0);	1738	ev_run (loop, 0);
1630		1739
1631		1740
1632	=head2 C<ev_timer> - relative and optionally repeating timeouts	1741	=head2 C<ev_timer> - relative and optionally repeating timeouts
1633		1742
1634	Timer watchers are simple relative timers that generate an event after a	1743	Timer watchers are simple relative timers that generate an event after a
…		…
1643	The callback is guaranteed to be invoked only I<after> its timeout has	1752	The callback is guaranteed to be invoked only I<after> its timeout has
1644	passed (not I<at>, so on systems with very low-resolution clocks this	1753	passed (not I<at>, so on systems with very low-resolution clocks this
1645	might introduce a small delay). If multiple timers become ready during the	1754	might introduce a small delay). If multiple timers become ready during the
1646	same loop iteration then the ones with earlier time-out values are invoked	1755	same loop iteration then the ones with earlier time-out values are invoked
1647	before ones of the same priority with later time-out values (but this is	1756	before ones of the same priority with later time-out values (but this is
1648	no longer true when a callback calls C<ev_loop> recursively).	1757	no longer true when a callback calls C<ev_run> recursively).
1649		1758
1650	=head3 Be smart about timeouts	1759	=head3 Be smart about timeouts
1651		1760
1652	Many real-world problems involve some kind of timeout, usually for error	1761	Many real-world problems involve some kind of timeout, usually for error
1653	recovery. A typical example is an HTTP request - if the other side hangs,	1762	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1824		1933
1825	=head3 The special problem of time updates	1934	=head3 The special problem of time updates
1826		1935
1827	Establishing the current time is a costly operation (it usually takes at	1936	Establishing the current time is a costly operation (it usually takes at
1828	least two system calls): EV therefore updates its idea of the current	1937	least two system calls): EV therefore updates its idea of the current
1829	time only before and after C<ev_loop> collects new events, which causes a	1938	time only before and after C<ev_run> collects new events, which causes a
1830	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1939	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1831	lots of events in one iteration.	1940	lots of events in one iteration.
1832		1941
1833	The relative timeouts are calculated relative to the C<ev_now ()>	1942	The relative timeouts are calculated relative to the C<ev_now ()>
1834	time. This is usually the right thing as this timestamp refers to the time	1943	time. This is usually the right thing as this timestamp refers to the time
…		…
1951	}	2060	}
1952		2061
1953	ev_timer mytimer;	2062	ev_timer mytimer;
1954	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2063	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1955	ev_timer_again (&mytimer); /* start timer */	2064	ev_timer_again (&mytimer); /* start timer */
1956	ev_loop (loop, 0);	2065	ev_run (loop, 0);
1957		2066
1958	// and in some piece of code that gets executed on any "activity":	2067	// and in some piece of code that gets executed on any "activity":
1959	// reset the timeout to start ticking again at 10 seconds	2068	// reset the timeout to start ticking again at 10 seconds
1960	ev_timer_again (&mytimer);	2069	ev_timer_again (&mytimer);
1961		2070
…		…
1987		2096
1988	As with timers, the callback is guaranteed to be invoked only when the	2097	As with timers, the callback is guaranteed to be invoked only when the
1989	point in time where it is supposed to trigger has passed. If multiple	2098	point in time where it is supposed to trigger has passed. If multiple
1990	timers become ready during the same loop iteration then the ones with	2099	timers become ready during the same loop iteration then the ones with
1991	earlier time-out values are invoked before ones with later time-out values	2100	earlier time-out values are invoked before ones with later time-out values
1992	(but this is no longer true when a callback calls C<ev_loop> recursively).	2101	(but this is no longer true when a callback calls C<ev_run> recursively).
1993		2102
1994	=head3 Watcher-Specific Functions and Data Members	2103	=head3 Watcher-Specific Functions and Data Members
1995		2104
1996	=over 4	2105	=over 4
1997		2106
…		…
2158		2267
2159	=head2 C<ev_signal> - signal me when a signal gets signalled!	2268	=head2 C<ev_signal> - signal me when a signal gets signalled!
2160		2269
2161	Signal watchers will trigger an event when the process receives a specific	2270	Signal watchers will trigger an event when the process receives a specific
2162	signal one or more times. Even though signals are very asynchronous, libev	2271	signal one or more times. Even though signals are very asynchronous, libev
2163	will try it's best to deliver signals synchronously, i.e. as part of the	2272	will try its best to deliver signals synchronously, i.e. as part of the
2164	normal event processing, like any other event.	2273	normal event processing, like any other event.
2165		2274
2166	If you want signals to be delivered truly asynchronously, just use	2275	If you want signals to be delivered truly asynchronously, just use
2167	C<sigaction> as you would do without libev and forget about sharing	2276	C<sigaction> as you would do without libev and forget about sharing
2168	the signal. You can even use C<ev_async> from a signal handler to	2277	the signal. You can even use C<ev_async> from a signal handler to
…		…
2235	Example: Try to exit cleanly on SIGINT.	2344	Example: Try to exit cleanly on SIGINT.
2236		2345
2237	static void	2346	static void
2238	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2347	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2239	{	2348	{
2240	ev_unloop (loop, EVUNLOOP_ALL);	2349	ev_break (loop, EVBREAK_ALL);
2241	}	2350	}
2242		2351
2243	ev_signal signal_watcher;	2352	ev_signal signal_watcher;
2244	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2353	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2245	ev_signal_start (loop, &signal_watcher);	2354	ev_signal_start (loop, &signal_watcher);
…		…
2631		2740
2632	Prepare and check watchers are usually (but not always) used in pairs:	2741	Prepare and check watchers are usually (but not always) used in pairs:
2633	prepare watchers get invoked before the process blocks and check watchers	2742	prepare watchers get invoked before the process blocks and check watchers
2634	afterwards.	2743	afterwards.
2635		2744
2636	You I<must not> call C<ev_loop> or similar functions that enter	2745	You I<must not> call C<ev_run> or similar functions that enter
2637	the current event loop from either C<ev_prepare> or C<ev_check>	2746	the current event loop from either C<ev_prepare> or C<ev_check>
2638	watchers. Other loops than the current one are fine, however. The	2747	watchers. Other loops than the current one are fine, however. The
2639	rationale behind this is that you do not need to check for recursion in	2748	rationale behind this is that you do not need to check for recursion in
2640	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2749	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2641	C<ev_check> so if you have one watcher of each kind they will always be	2750	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2809		2918
2810	if (timeout >= 0)	2919	if (timeout >= 0)
2811	// create/start timer	2920	// create/start timer
2812		2921
2813	// poll	2922	// poll
2814	ev_loop (EV_A_ 0);	2923	ev_run (EV_A_ 0);
2815		2924
2816	// stop timer again	2925	// stop timer again
2817	if (timeout >= 0)	2926	if (timeout >= 0)
2818	ev_timer_stop (EV_A_ &to);	2927	ev_timer_stop (EV_A_ &to);
2819		2928
…		…
2897	if you do not want that, you need to temporarily stop the embed watcher).	3006	if you do not want that, you need to temporarily stop the embed watcher).
2898		3007
2899	=item ev_embed_sweep (loop, ev_embed *)	3008	=item ev_embed_sweep (loop, ev_embed *)
2900		3009
2901	Make a single, non-blocking sweep over the embedded loop. This works	3010	Make a single, non-blocking sweep over the embedded loop. This works
2902	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	3011	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2903	appropriate way for embedded loops.	3012	appropriate way for embedded loops.
2904		3013
2905	=item struct ev_loop *other [read-only]	3014	=item struct ev_loop *other [read-only]
2906		3015
2907	The embedded event loop.	3016	The embedded event loop.
…		…
2993	disadvantage of having to use multiple event loops (which do not support	3102	disadvantage of having to use multiple event loops (which do not support
2994	signal watchers).	3103	signal watchers).
2995		3104
2996	When this is not possible, or you want to use the default loop for	3105	When this is not possible, or you want to use the default loop for
2997	other reasons, then in the process that wants to start "fresh", call	3106	other reasons, then in the process that wants to start "fresh", call
2998	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3107	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2999	the default loop will "orphan" (not stop) all registered watchers, so you	3108	Destroying the default loop will "orphan" (not stop) all registered
3000	have to be careful not to execute code that modifies those watchers. Note	3109	watchers, so you have to be careful not to execute code that modifies
3001	also that in that case, you have to re-register any signal watchers.	3110	those watchers. Note also that in that case, you have to re-register any
		3111	signal watchers.
3002		3112
3003	=head3 Watcher-Specific Functions and Data Members	3113	=head3 Watcher-Specific Functions and Data Members
3004		3114
3005	=over 4	3115	=over 4
3006		3116
3007	=item ev_fork_init (ev_signal *, callback)	3117	=item ev_fork_init (ev_fork *, callback)
3008		3118
3009	Initialises and configures the fork watcher - it has no parameters of any	3119	Initialises and configures the fork watcher - it has no parameters of any
3010	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,	3120	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3011	believe me.	3121	really.
3012		3122
3013	=back	3123	=back
3014		3124
3015		3125
		3126	=head2 C<ev_cleanup> - even the best things end
		3127
		3128	Cleanup watchers are called just before the event loop is being destroyed
		3129	by a call to C<ev_loop_destroy>.
		3130
		3131	While there is no guarantee that the event loop gets destroyed, cleanup
		3132	watchers provide a convenient method to install cleanup hooks for your
		3133	program, worker threads and so on - you just to make sure to destroy the
		3134	loop when you want them to be invoked.
		3135
		3136	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3137	all other watchers, they do not keep a reference to the event loop (which
		3138	makes a lot of sense if you think about it). Like all other watchers, you
		3139	can call libev functions in the callback, except C<ev_cleanup_start>.
		3140
		3141	=head3 Watcher-Specific Functions and Data Members
		3142
		3143	=over 4
		3144
		3145	=item ev_cleanup_init (ev_cleanup *, callback)
		3146
		3147	Initialises and configures the cleanup watcher - it has no parameters of
		3148	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3149	pointless, I assure you.
		3150
		3151	=back
		3152
		3153	Example: Register an atexit handler to destroy the default loop, so any
		3154	cleanup functions are called.
		3155
		3156	static void
		3157	program_exits (void)
		3158	{
		3159	ev_loop_destroy (EV_DEFAULT_UC);
		3160	}
		3161
		3162	...
		3163	atexit (program_exits);
		3164
		3165
3016	=head2 C<ev_async> - how to wake up an event loop	3166	=head2 C<ev_async> - how to wake up an event loop
3017		3167
3018	In general, you cannot use an C<ev_loop> from multiple threads or other	3168	In general, you cannot use an C<ev_run> from multiple threads or other
3019	asynchronous sources such as signal handlers (as opposed to multiple event	3169	asynchronous sources such as signal handlers (as opposed to multiple event
3020	loops - those are of course safe to use in different threads).	3170	loops - those are of course safe to use in different threads).
3021		3171
3022	Sometimes, however, you need to wake up an event loop you do not control,	3172	Sometimes, however, you need to wake up an event loop you do not control,
3023	for example because it belongs to another thread. This is what C<ev_async>	3173	for example because it belongs to another thread. This is what C<ev_async>
…		…
3217	loop!).	3367	loop!).
3218		3368
3219	=back	3369	=back
3220		3370
3221		3371
		3372	=head1 COMMON OR USEFUL IDIOMS (OR BOTH)
		3373
		3374	This section explains some common idioms that are not immediately
		3375	obvious. Note that examples are sprinkled over the whole manual, and this
		3376	section only contains stuff that wouldn't fit anywhere else.
		3377
		3378	=over 4
		3379
		3380	=item Model/nested event loop invocations and exit conditions.
		3381
		3382	Often (especially in GUI toolkits) there are places where you have
		3383	I<modal> interaction, which is most easily implemented by recursively
		3384	invoking C<ev_run>.
		3385
		3386	This brings the problem of exiting - a callback might want to finish the
		3387	main C<ev_run> call, but not the nested one (e.g. user clicked "Quit", but
		3388	a modal "Are you sure?" dialog is still waiting), or just the nested one
		3389	and not the main one (e.g. user clocked "Ok" in a modal dialog), or some
		3390	other combination: In these cases, C<ev_break> will not work alone.
		3391
		3392	The solution is to maintain "break this loop" variable for each C<ev_run>
		3393	invocation, and use a loop around C<ev_run> until the condition is
		3394	triggered, using C<EVRUN_ONCE>:
		3395
		3396	// main loop
		3397	int exit_main_loop = 0;
		3398
		3399	while (!exit_main_loop)
		3400	ev_run (EV_DEFAULT_ EVRUN_ONCE);
		3401
		3402	// in a model watcher
		3403	int exit_nested_loop = 0;
		3404
		3405	while (!exit_nested_loop)
		3406	ev_run (EV_A_ EVRUN_ONCE);
		3407
		3408	To exit from any of these loops, just set the corresponding exit variable:
		3409
		3410	// exit modal loop
		3411	exit_nested_loop = 1;
		3412
		3413	// exit main program, after modal loop is finished
		3414	exit_main_loop = 1;
		3415
		3416	// exit both
		3417	exit_main_loop = exit_nested_loop = 1;
		3418
		3419	=back
		3420
		3421
3222	=head1 LIBEVENT EMULATION	3422	=head1 LIBEVENT EMULATION
3223		3423
3224	Libev offers a compatibility emulation layer for libevent. It cannot	3424	Libev offers a compatibility emulation layer for libevent. It cannot
3225	emulate the internals of libevent, so here are some usage hints:	3425	emulate the internals of libevent, so here are some usage hints:
3226		3426
3227	=over 4	3427	=over 4
		3428
		3429	=item * Only the libevent-1.4.1-beta API is being emulated.
		3430
		3431	This was the newest libevent version available when libev was implemented,
		3432	and is still mostly uncanged in 2010.
3228		3433
3229	=item * Use it by including <event.h>, as usual.	3434	=item * Use it by including <event.h>, as usual.
3230		3435
3231	=item * The following members are fully supported: ev_base, ev_callback,	3436	=item * The following members are fully supported: ev_base, ev_callback,
3232	ev_arg, ev_fd, ev_res, ev_events.	3437	ev_arg, ev_fd, ev_res, ev_events.
…		…
3238	=item * Priorities are not currently supported. Initialising priorities	3443	=item * Priorities are not currently supported. Initialising priorities
3239	will fail and all watchers will have the same priority, even though there	3444	will fail and all watchers will have the same priority, even though there
3240	is an ev_pri field.	3445	is an ev_pri field.
3241		3446
3242	=item * In libevent, the last base created gets the signals, in libev, the	3447	=item * In libevent, the last base created gets the signals, in libev, the
3243	first base created (== the default loop) gets the signals.	3448	base that registered the signal gets the signals.
3244		3449
3245	=item * Other members are not supported.	3450	=item * Other members are not supported.
3246		3451
3247	=item * The libev emulation is I<not> ABI compatible to libevent, you need	3452	=item * The libev emulation is I<not> ABI compatible to libevent, you need
3248	to use the libev header file and library.	3453	to use the libev header file and library.
…		…
3267	Care has been taken to keep the overhead low. The only data member the C++	3472	Care has been taken to keep the overhead low. The only data member the C++
3268	classes add (compared to plain C-style watchers) is the event loop pointer	3473	classes add (compared to plain C-style watchers) is the event loop pointer
3269	that the watcher is associated with (or no additional members at all if	3474	that the watcher is associated with (or no additional members at all if
3270	you disable C<EV_MULTIPLICITY> when embedding libev).	3475	you disable C<EV_MULTIPLICITY> when embedding libev).
3271		3476
3272	Currently, functions, and static and non-static member functions can be	3477	Currently, functions, static and non-static member functions and classes
3273	used as callbacks. Other types should be easy to add as long as they only	3478	with C<operator ()> can be used as callbacks. Other types should be easy
3274	need one additional pointer for context. If you need support for other	3479	to add as long as they only need one additional pointer for context. If
3275	types of functors please contact the author (preferably after implementing	3480	you need support for other types of functors please contact the author
3276	it).	3481	(preferably after implementing it).
3277		3482
3278	Here is a list of things available in the C<ev> namespace:	3483	Here is a list of things available in the C<ev> namespace:
3279		3484
3280	=over 4	3485	=over 4
3281		3486
…		…
3391	Associates a different C<struct ev_loop> with this watcher. You can only	3596	Associates a different C<struct ev_loop> with this watcher. You can only
3392	do this when the watcher is inactive (and not pending either).	3597	do this when the watcher is inactive (and not pending either).
3393		3598
3394	=item w->set ([arguments])	3599	=item w->set ([arguments])
3395		3600
3396	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3601	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3397	called at least once. Unlike the C counterpart, an active watcher gets	3602	method or a suitable start method must be called at least once. Unlike the
3398	automatically stopped and restarted when reconfiguring it with this	3603	C counterpart, an active watcher gets automatically stopped and restarted
3399	method.	3604	when reconfiguring it with this method.
3400		3605
3401	=item w->start ()	3606	=item w->start ()
3402		3607
3403	Starts the watcher. Note that there is no C<loop> argument, as the	3608	Starts the watcher. Note that there is no C<loop> argument, as the
3404	constructor already stores the event loop.	3609	constructor already stores the event loop.
3405		3610
		3611	=item w->start ([arguments])
		3612
		3613	Instead of calling C<set> and C<start> methods separately, it is often
		3614	convenient to wrap them in one call. Uses the same type of arguments as
		3615	the configure C<set> method of the watcher.
		3616
3406	=item w->stop ()	3617	=item w->stop ()
3407		3618
3408	Stops the watcher if it is active. Again, no C<loop> argument.	3619	Stops the watcher if it is active. Again, no C<loop> argument.
3409		3620
3410	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3621	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3422		3633
3423	=back	3634	=back
3424		3635
3425	=back	3636	=back
3426		3637
3427	Example: Define a class with an IO and idle watcher, start one of them in	3638	Example: Define a class with two I/O and idle watchers, start the I/O
3428	the constructor.	3639	watchers in the constructor.
3429		3640
3430	class myclass	3641	class myclass
3431	{	3642	{
3432	ev::io io ; void io_cb (ev::io &w, int revents);	3643	ev::io io ; void io_cb (ev::io &w, int revents);
		3644	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3433	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3645	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3434		3646
3435	myclass (int fd)	3647	myclass (int fd)
3436	{	3648	{
3437	io .set <myclass, &myclass::io_cb > (this);	3649	io .set <myclass, &myclass::io_cb > (this);
		3650	io2 .set <myclass, &myclass::io2_cb > (this);
3438	idle.set <myclass, &myclass::idle_cb> (this);	3651	idle.set <myclass, &myclass::idle_cb> (this);
3439		3652
3440	io.start (fd, ev::READ);	3653	io.set (fd, ev::WRITE); // configure the watcher
		3654	io.start (); // start it whenever convenient
		3655
		3656	io2.start (fd, ev::READ); // set + start in one call
3441	}	3657	}
3442	};	3658	};
3443		3659
3444		3660
3445	=head1 OTHER LANGUAGE BINDINGS	3661	=head1 OTHER LANGUAGE BINDINGS
…		…
3519	loop argument"). The C<EV_A> form is used when this is the sole argument,	3735	loop argument"). The C<EV_A> form is used when this is the sole argument,
3520	C<EV_A_> is used when other arguments are following. Example:	3736	C<EV_A_> is used when other arguments are following. Example:
3521		3737
3522	ev_unref (EV_A);	3738	ev_unref (EV_A);
3523	ev_timer_add (EV_A_ watcher);	3739	ev_timer_add (EV_A_ watcher);
3524	ev_loop (EV_A_ 0);	3740	ev_run (EV_A_ 0);
3525		3741
3526	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3742	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3527	which is often provided by the following macro.	3743	which is often provided by the following macro.
3528		3744
3529	=item C<EV_P>, C<EV_P_>	3745	=item C<EV_P>, C<EV_P_>
…		…
3569	}	3785	}
3570		3786
3571	ev_check check;	3787	ev_check check;
3572	ev_check_init (&check, check_cb);	3788	ev_check_init (&check, check_cb);
3573	ev_check_start (EV_DEFAULT_ &check);	3789	ev_check_start (EV_DEFAULT_ &check);
3574	ev_loop (EV_DEFAULT_ 0);	3790	ev_run (EV_DEFAULT_ 0);
3575		3791
3576	=head1 EMBEDDING	3792	=head1 EMBEDDING
3577		3793
3578	Libev can (and often is) directly embedded into host	3794	Libev can (and often is) directly embedded into host
3579	applications. Examples of applications that embed it include the Deliantra	3795	applications. Examples of applications that embed it include the Deliantra
…		…
3670	to a compiled library. All other symbols change the ABI, which means all	3886	to a compiled library. All other symbols change the ABI, which means all
3671	users of libev and the libev code itself must be compiled with compatible	3887	users of libev and the libev code itself must be compiled with compatible
3672	settings.	3888	settings.
3673		3889
3674	=over 4	3890	=over 4
		3891
		3892	=item EV_COMPAT3 (h)
		3893
		3894	Backwards compatibility is a major concern for libev. This is why this
		3895	release of libev comes with wrappers for the functions and symbols that
		3896	have been renamed between libev version 3 and 4.
		3897
		3898	You can disable these wrappers (to test compatibility with future
		3899	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3900	sources. This has the additional advantage that you can drop the C<struct>
		3901	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3902	typedef in that case.
		3903
		3904	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3905	and in some even more future version the compatibility code will be
		3906	removed completely.
3675		3907
3676	=item EV_STANDALONE (h)	3908	=item EV_STANDALONE (h)
3677		3909
3678	Must always be C<1> if you do not use autoconf configuration, which	3910	Must always be C<1> if you do not use autoconf configuration, which
3679	keeps libev from including F<config.h>, and it also defines dummy	3911	keeps libev from including F<config.h>, and it also defines dummy
…		…
4029	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4261	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4030	will be C<0>.	4262	will be C<0>.
4031		4263
4032	=item EV_VERIFY	4264	=item EV_VERIFY
4033		4265
4034	Controls how much internal verification (see C<ev_loop_verify ()>) will	4266	Controls how much internal verification (see C<ev_verify ()>) will
4035	be done: If set to C<0>, no internal verification code will be compiled	4267	be done: If set to C<0>, no internal verification code will be compiled
4036	in. If set to C<1>, then verification code will be compiled in, but not	4268	in. If set to C<1>, then verification code will be compiled in, but not
4037	called. If set to C<2>, then the internal verification code will be	4269	called. If set to C<2>, then the internal verification code will be
4038	called once per loop, which can slow down libev. If set to C<3>, then the	4270	called once per loop, which can slow down libev. If set to C<3>, then the
4039	verification code will be called very frequently, which will slow down	4271	verification code will be called very frequently, which will slow down
…		…
4254	userdata *u = ev_userdata (EV_A);	4486	userdata *u = ev_userdata (EV_A);
4255	pthread_mutex_lock (&u->lock);	4487	pthread_mutex_lock (&u->lock);
4256	}	4488	}
4257		4489
4258	The event loop thread first acquires the mutex, and then jumps straight	4490	The event loop thread first acquires the mutex, and then jumps straight
4259	into C<ev_loop>:	4491	into C<ev_run>:
4260		4492
4261	void *	4493	void *
4262	l_run (void *thr_arg)	4494	l_run (void *thr_arg)
4263	{	4495	{
4264	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4496	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4265		4497
4266	l_acquire (EV_A);	4498	l_acquire (EV_A);
4267	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4499	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4268	ev_loop (EV_A_ 0);	4500	ev_run (EV_A_ 0);
4269	l_release (EV_A);	4501	l_release (EV_A);
4270		4502
4271	return 0;	4503	return 0;
4272	}	4504	}
4273		4505
…		…
4325		4557
4326	=head3 COROUTINES	4558	=head3 COROUTINES
4327		4559
4328	Libev is very accommodating to coroutines ("cooperative threads"):	4560	Libev is very accommodating to coroutines ("cooperative threads"):
4329	libev fully supports nesting calls to its functions from different	4561	libev fully supports nesting calls to its functions from different
4330	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4562	coroutines (e.g. you can call C<ev_run> on the same loop from two
4331	different coroutines, and switch freely between both coroutines running	4563	different coroutines, and switch freely between both coroutines running
4332	the loop, as long as you don't confuse yourself). The only exception is	4564	the loop, as long as you don't confuse yourself). The only exception is
4333	that you must not do this from C<ev_periodic> reschedule callbacks.	4565	that you must not do this from C<ev_periodic> reschedule callbacks.
4334		4566
4335	Care has been taken to ensure that libev does not keep local state inside	4567	Care has been taken to ensure that libev does not keep local state inside
4336	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4568	C<ev_run>, and other calls do not usually allow for coroutine switches as
4337	they do not call any callbacks.	4569	they do not call any callbacks.
4338		4570
4339	=head2 COMPILER WARNINGS	4571	=head2 COMPILER WARNINGS
4340		4572
4341	Depending on your compiler and compiler settings, you might get no or a	4573	Depending on your compiler and compiler settings, you might get no or a
…		…
4425	=head3 C<kqueue> is buggy	4657	=head3 C<kqueue> is buggy
4426		4658
4427	The kqueue syscall is broken in all known versions - most versions support	4659	The kqueue syscall is broken in all known versions - most versions support
4428	only sockets, many support pipes.	4660	only sockets, many support pipes.
4429		4661
4430	Libev tries to work around this by not using C<kqueue> by default on	4662	Libev tries to work around this by not using C<kqueue> by default on this
4431	this rotten platform, but of course you can still ask for it when creating	4663	rotten platform, but of course you can still ask for it when creating a
4432	a loop.	4664	loop - embedding a socket-only kqueue loop into a select-based one is
		4665	probably going to work well.
4433		4666
4434	=head3 C<poll> is buggy	4667	=head3 C<poll> is buggy
4435		4668
4436	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>	4669	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
4437	implementation by something calling C<kqueue> internally around the 10.5.6	4670	implementation by something calling C<kqueue> internally around the 10.5.6
…		…
4456		4689
4457	=head3 C<errno> reentrancy	4690	=head3 C<errno> reentrancy
4458		4691
4459	The default compile environment on Solaris is unfortunately so	4692	The default compile environment on Solaris is unfortunately so
4460	thread-unsafe that you can't even use components/libraries compiled	4693	thread-unsafe that you can't even use components/libraries compiled
4461	without C<-D_REENTRANT> (as long as they use C<errno>), which, of course,	4694	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
4462	isn't defined by default.	4695	defined by default. A valid, if stupid, implementation choice.
4463		4696
4464	If you want to use libev in threaded environments you have to make sure	4697	If you want to use libev in threaded environments you have to make sure
4465	it's compiled with C<_REENTRANT> defined.	4698	it's compiled with C<_REENTRANT> defined.
4466		4699
4467	=head3 Event port backend	4700	=head3 Event port backend
4468		4701
4469	The scalable event interface for Solaris is called "event ports". Unfortunately,	4702	The scalable event interface for Solaris is called "event
4470	this mechanism is very buggy. If you run into high CPU usage, your program	4703	ports". Unfortunately, this mechanism is very buggy in all major
		4704	releases. If you run into high CPU usage, your program freezes or you get
4471	freezes or you get a large number of spurious wakeups, make sure you have	4705	a large number of spurious wakeups, make sure you have all the relevant
4472	all the relevant and latest kernel patches applied. No, I don't know which	4706	and latest kernel patches applied. No, I don't know which ones, but there
4473	ones, but there are multiple ones.	4707	are multiple ones to apply, and afterwards, event ports actually work
		4708	great.
4474		4709
4475	If you can't get it to work, you can try running the program by setting	4710	If you can't get it to work, you can try running the program by setting
4476	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and	4711	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
4477	C<select> backends.	4712	C<select> backends.
4478		4713
4479	=head2 AIX POLL BUG	4714	=head2 AIX POLL BUG
4480		4715
4481	AIX unfortunately has a broken C<poll.h> header. Libev works around	4716	AIX unfortunately has a broken C<poll.h> header. Libev works around
4482	this by trying to avoid the poll backend altogether (i.e. it's not even	4717	this by trying to avoid the poll backend altogether (i.e. it's not even
4483	compiled in), which normally isn't a big problem as C<select> works fine	4718	compiled in), which normally isn't a big problem as C<select> works fine
4484	with large bitsets, and AIX is dead anyway.	4719	with large bitsets on AIX, and AIX is dead anyway.
4485		4720
4486	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4721	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
4487		4722
4488	=head3 General issues	4723	=head3 General issues
4489		4724
…		…
4595	structure (guaranteed by POSIX but not by ISO C for example), but it also	4830	structure (guaranteed by POSIX but not by ISO C for example), but it also
4596	assumes that the same (machine) code can be used to call any watcher	4831	assumes that the same (machine) code can be used to call any watcher
4597	callback: The watcher callbacks have different type signatures, but libev	4832	callback: The watcher callbacks have different type signatures, but libev
4598	calls them using an C<ev_watcher *> internally.	4833	calls them using an C<ev_watcher *> internally.
4599		4834
		4835	=item pointer accesses must be thread-atomic
		4836
		4837	Accessing a pointer value must be atomic, it must both be readable and
		4838	writable in one piece - this is the case on all current architectures.
		4839
4600	=item C<sig_atomic_t volatile> must be thread-atomic as well	4840	=item C<sig_atomic_t volatile> must be thread-atomic as well
4601		4841
4602	The type C<sig_atomic_t volatile> (or whatever is defined as	4842	The type C<sig_atomic_t volatile> (or whatever is defined as
4603	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different	4843	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
4604	threads. This is not part of the specification for C<sig_atomic_t>, but is	4844	threads. This is not part of the specification for C<sig_atomic_t>, but is
…		…
4626	watchers.	4866	watchers.
4627		4867
4628	=item C<double> must hold a time value in seconds with enough accuracy	4868	=item C<double> must hold a time value in seconds with enough accuracy
4629		4869
4630	The type C<double> is used to represent timestamps. It is required to	4870	The type C<double> is used to represent timestamps. It is required to
4631	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4871	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4632	enough for at least into the year 4000. This requirement is fulfilled by	4872	good enough for at least into the year 4000 with millisecond accuracy
		4873	(the design goal for libev). This requirement is overfulfilled by
4633	implementations implementing IEEE 754, which is basically all existing	4874	implementations using IEEE 754, which is basically all existing ones. With
4634	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4875	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4635	2200.
4636		4876
4637	=back	4877	=back
4638		4878
4639	If you know of other additional requirements drop me a note.	4879	If you know of other additional requirements drop me a note.
4640		4880
…		…
4710	=back	4950	=back
4711		4951
4712		4952
4713	=head1 PORTING FROM LIBEV 3.X TO 4.X	4953	=head1 PORTING FROM LIBEV 3.X TO 4.X
4714		4954
4715	The major version 4 introduced some minor incompatible changes to the API.	4955	The major version 4 introduced some incompatible changes to the API.
4716		4956
4717	At the moment, the C<ev.h> header file tries to implement superficial	4957	At the moment, the C<ev.h> header file provides compatibility definitions
4718	compatibility, so most programs should still compile. Those might be	4958	for all changes, so most programs should still compile. The compatibility
4719	removed in later versions of libev, so better update early than late.	4959	layer might be removed in later versions of libev, so better update to the
		4960	new API early than late.
4720		4961
4721	=over 4	4962	=over 4
4722		4963
4723	=item C<ev_loop_count> renamed to C<ev_iteration>	4964	=item C<EV_COMPAT3> backwards compatibility mechanism
4724		4965
4725	=item C<ev_loop_depth> renamed to C<ev_depth>	4966	The backward compatibility mechanism can be controlled by
		4967	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4968	section.
4726		4969
4727	=item C<ev_loop_verify> renamed to C<ev_verify>	4970	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4971
		4972	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4973
		4974	ev_loop_destroy (EV_DEFAULT_UC);
		4975	ev_loop_fork (EV_DEFAULT);
		4976
		4977	=item function/symbol renames
		4978
		4979	A number of functions and symbols have been renamed:
		4980
		4981	ev_loop => ev_run
		4982	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4983	EVLOOP_ONESHOT => EVRUN_ONCE
		4984
		4985	ev_unloop => ev_break
		4986	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4987	EVUNLOOP_ONE => EVBREAK_ONE
		4988	EVUNLOOP_ALL => EVBREAK_ALL
		4989
		4990	EV_TIMEOUT => EV_TIMER
		4991
		4992	ev_loop_count => ev_iteration
		4993	ev_loop_depth => ev_depth
		4994	ev_loop_verify => ev_verify
4728		4995
4729	Most functions working on C<struct ev_loop> objects don't have an	4996	Most functions working on C<struct ev_loop> objects don't have an
4730	C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is	4997	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4998	associated constants have been renamed to not collide with the C<struct
		4999	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		5000	as all other watcher types. Note that C<ev_loop_fork> is still called
4731	still called C<ev_loop_fork> because it would otherwise clash with the	5001	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4732	C<ev_fork> typedef.	5002	typedef.
4733
4734	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>
4735
4736	This is a simple rename - all other watcher types use their name
4737	as revents flag, and now C<ev_timer> does, too.
4738
4739	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4740	and continue to be present for the foreseeable future, so this is mostly a
4741	documentation change.
4742		5003
4743	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	5004	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4744		5005
4745	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	5006	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4746	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	5007	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
…		…
4753		5014
4754	=over 4	5015	=over 4
4755		5016
4756	=item active	5017	=item active
4757		5018
4758	A watcher is active as long as it has been started (has been attached to	5019	A watcher is active as long as it has been started and not yet stopped.
4759	an event loop) but not yet stopped (disassociated from the event loop).	5020	See L<WATCHER STATES> for details.
4760		5021
4761	=item application	5022	=item application
4762		5023
4763	In this document, an application is whatever is using libev.	5024	In this document, an application is whatever is using libev.
		5025
		5026	=item backend
		5027
		5028	The part of the code dealing with the operating system interfaces.
4764		5029
4765	=item callback	5030	=item callback
4766		5031
4767	The address of a function that is called when some event has been	5032	The address of a function that is called when some event has been
4768	detected. Callbacks are being passed the event loop, the watcher that	5033	detected. Callbacks are being passed the event loop, the watcher that
4769	received the event, and the actual event bitset.	5034	received the event, and the actual event bitset.
4770		5035
4771	=item callback invocation	5036	=item callback/watcher invocation
4772		5037
4773	The act of calling the callback associated with a watcher.	5038	The act of calling the callback associated with a watcher.
4774		5039
4775	=item event	5040	=item event
4776		5041
…		…
4795	The model used to describe how an event loop handles and processes	5060	The model used to describe how an event loop handles and processes
4796	watchers and events.	5061	watchers and events.
4797		5062
4798	=item pending	5063	=item pending
4799		5064
4800	A watcher is pending as soon as the corresponding event has been detected,	5065	A watcher is pending as soon as the corresponding event has been
4801	and stops being pending as soon as the watcher will be invoked or its	5066	detected. See L<WATCHER STATES> for details.
4802	pending status is explicitly cleared by the application.
4803
4804	A watcher can be pending, but not active. Stopping a watcher also clears
4805	its pending status.
4806		5067
4807	=item real time	5068	=item real time
4808		5069
4809	The physical time that is observed. It is apparently strictly monotonic :)	5070	The physical time that is observed. It is apparently strictly monotonic :)
4810		5071
…		…
4817	=item watcher	5078	=item watcher
4818		5079
4819	A data structure that describes interest in certain events. Watchers need	5080	A data structure that describes interest in certain events. Watchers need
4820	to be started (attached to an event loop) before they can receive events.	5081	to be started (attached to an event loop) before they can receive events.
4821		5082
4822	=item watcher invocation
4823
4824	The act of calling the callback associated with a watcher.
4825
4826	=back	5083	=back
4827		5084
4828	=head1 AUTHOR	5085	=head1 AUTHOR
4829		5086
4830	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5087	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
		5088	Magnusson and Emanuele Giaquinta.
4831		5089

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