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Revision 1.286 by root, Tue Mar 16 00:26:41 2010 UTC vs.
Revision 1.333 by root, Mon Oct 25 09:31:47 2010 UTC

…		…
26	puts ("stdin ready");	26	puts ("stdin ready");
27	// for one-shot events, one must manually stop the watcher	27	// for one-shot events, one must manually stop the watcher
28	// with its corresponding stop function.	28	// with its corresponding stop function.
29	ev_io_stop (EV_A_ w);	29	ev_io_stop (EV_A_ w);
30		30
31	// this causes all nested ev_loop's to stop iterating	31	// this causes all nested ev_run's to stop iterating
32	ev_unloop (EV_A_ EVUNLOOP_ALL);	32	ev_break (EV_A_ EVBREAK_ALL);
33	}	33	}
34		34
35	// another callback, this time for a time-out	35	// another callback, this time for a time-out
36	static void	36	static void
37	timeout_cb (EV_P_ ev_timer *w, int revents)	37	timeout_cb (EV_P_ ev_timer *w, int revents)
38	{	38	{
39	puts ("timeout");	39	puts ("timeout");
40	// this causes the innermost ev_loop to stop iterating	40	// this causes the innermost ev_run to stop iterating
41	ev_unloop (EV_A_ EVUNLOOP_ONE);	41	ev_break (EV_A_ EVBREAK_ONE);
42	}	42	}
43		43
44	int	44	int
45	main (void)	45	main (void)
46	{	46	{
47	// use the default event loop unless you have special needs	47	// use the default event loop unless you have special needs
48	struct ev_loop *loop = ev_default_loop (0);	48	struct ev_loop *loop = EV_DEFAULT;
49		49
50	// initialise an io watcher, then start it	50	// initialise an io watcher, then start it
51	// this one will watch for stdin to become readable	51	// this one will watch for stdin to become readable
52	ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);	52	ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
53	ev_io_start (loop, &stdin_watcher);	53	ev_io_start (loop, &stdin_watcher);
…		…
56	// simple non-repeating 5.5 second timeout	56	// simple non-repeating 5.5 second timeout
57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
58	ev_timer_start (loop, &timeout_watcher);	58	ev_timer_start (loop, &timeout_watcher);
59		59
60	// now wait for events to arrive	60	// now wait for events to arrive
61	ev_loop (loop, 0);	61	ev_run (loop, 0);
62		62
63	// unloop was called, so exit	63	// unloop was called, so exit
64	return 0;	64	return 0;
65	}	65	}
66		66
…		…
75	While this document tries to be as complete as possible in documenting	75	While this document tries to be as complete as possible in documenting
76	libev, its usage and the rationale behind its design, it is not a tutorial	76	libev, its usage and the rationale behind its design, it is not a tutorial
77	on event-based programming, nor will it introduce event-based programming	77	on event-based programming, nor will it introduce event-based programming
78	with libev.	78	with libev.
79		79
80	Familarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
82		82
83	=head1 ABOUT LIBEV	83	=head1 ABOUT LIBEV
84		84
85	Libev is an event loop: you register interest in certain events (such as a	85	Libev is an event loop: you register interest in certain events (such as a
…		…
124	this argument.	124	this argument.
125		125
126	=head2 TIME REPRESENTATION	126	=head2 TIME REPRESENTATION
127		127
128	Libev represents time as a single floating point number, representing	128	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (somewhere	129	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	near the beginning of 1970, details are complicated, don't ask). This	130	somewhere near the beginning of 1970, details are complicated, don't
131	type is called C<ev_tstamp>, which is what you should use too. It usually	131	ask). This type is called C<ev_tstamp>, which is what you should use
132	aliases to the C<double> type in C. When you need to do any calculations	132	too. It usually aliases to the C<double> type in C. When you need to do
133	on it, you should treat it as some floating point value. Unlike the name	133	any calculations on it, you should treat it as some floating point value.
		134
134	component C<stamp> might indicate, it is also used for time differences	135	Unlike the name component C<stamp> might indicate, it is also used for
135	throughout libev.	136	time differences (e.g. delays) throughout libev.
136		137
137	=head1 ERROR HANDLING	138	=head1 ERROR HANDLING
138		139
139	Libev knows three classes of errors: operating system errors, usage errors	140	Libev knows three classes of errors: operating system errors, usage errors
140	and internal errors (bugs).	141	and internal errors (bugs).
…		…
164		165
165	=item ev_tstamp ev_time ()	166	=item ev_tstamp ev_time ()
166		167
167	Returns the current time as libev would use it. Please note that the	168	Returns the current time as libev would use it. Please note that the
168	C<ev_now> function is usually faster and also often returns the timestamp	169	C<ev_now> function is usually faster and also often returns the timestamp
169	you actually want to know.	170	you actually want to know. Also interesting is the combination of
		171	C<ev_update_now> and C<ev_now>.
170		172
171	=item ev_sleep (ev_tstamp interval)	173	=item ev_sleep (ev_tstamp interval)
172		174
173	Sleep for the given interval: The current thread will be blocked until	175	Sleep for the given interval: The current thread will be blocked until
174	either it is interrupted or the given time interval has passed. Basically	176	either it is interrupted or the given time interval has passed. Basically
…		…
191	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
192	compatible to older versions, so a larger minor version alone is usually	194	compatible to older versions, so a larger minor version alone is usually
193	not a problem.	195	not a problem.
194		196
195	Example: Make sure we haven't accidentally been linked against the wrong	197	Example: Make sure we haven't accidentally been linked against the wrong
196	version.	198	version (note, however, that this will not detect other ABI mismatches,
		199	such as LFS or reentrancy).
197		200
198	assert (("libev version mismatch",	201	assert (("libev version mismatch",
199	ev_version_major () == EV_VERSION_MAJOR	202	ev_version_major () == EV_VERSION_MAJOR
200	&& ev_version_minor () >= EV_VERSION_MINOR));	203	&& ev_version_minor () >= EV_VERSION_MINOR));
201		204
…		…
212	assert (("sorry, no epoll, no sex",	215	assert (("sorry, no epoll, no sex",
213	ev_supported_backends () & EVBACKEND_EPOLL));	216	ev_supported_backends () & EVBACKEND_EPOLL));
214		217
215	=item unsigned int ev_recommended_backends ()	218	=item unsigned int ev_recommended_backends ()
216		219
217	Return the set of all backends compiled into this binary of libev and also	220	Return the set of all backends compiled into this binary of libev and
218	recommended for this platform. This set is often smaller than the one	221	also recommended for this platform, meaning it will work for most file
		222	descriptor types. This set is often smaller than the one returned by
219	returned by C<ev_supported_backends>, as for example kqueue is broken on	223	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
220	most BSDs and will not be auto-detected unless you explicitly request it	224	and will not be auto-detected unless you explicitly request it (assuming
221	(assuming you know what you are doing). This is the set of backends that	225	you know what you are doing). This is the set of backends that libev will
222	libev will probe for if you specify no backends explicitly.	226	probe for if you specify no backends explicitly.
223		227
224	=item unsigned int ev_embeddable_backends ()	228	=item unsigned int ev_embeddable_backends ()
225		229
226	Returns the set of backends that are embeddable in other event loops. This	230	Returns the set of backends that are embeddable in other event loops. This
227	is the theoretical, all-platform, value. To find which backends	231	value is platform-specific but can include backends not available on the
228	might be supported on the current system, you would need to look at	232	current system. To find which embeddable backends might be supported on
229	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	233	the current system, you would need to look at C<ev_embeddable_backends ()
230	recommended ones.	234	& ev_supported_backends ()>, likewise for recommended ones.
231		235
232	See the description of C<ev_embed> watchers for more info.	236	See the description of C<ev_embed> watchers for more info.
233		237
234	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]	238	=item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]
235		239
…		…
289	...	293	...
290	ev_set_syserr_cb (fatal_error);	294	ev_set_syserr_cb (fatal_error);
291		295
292	=back	296	=back
293		297
294	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	298	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
295		299
296	An event loop is described by a C<struct ev_loop *> (the C<struct>	300	An event loop is described by a C<struct ev_loop *> (the C<struct> is
297	is I<not> optional in this case, as there is also an C<ev_loop>	301	I<not> optional in this case unless libev 3 compatibility is disabled, as
298	I<function>).	302	libev 3 had an C<ev_loop> function colliding with the struct name).
299		303
300	The library knows two types of such loops, the I<default> loop, which	304	The library knows two types of such loops, the I<default> loop, which
301	supports signals and child events, and dynamically created loops which do	305	supports child process events, and dynamically created event loops which
302	not.	306	do not.
303		307
304	=over 4	308	=over 4
305		309
306	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
307		311
308	This will initialise the default event loop if it hasn't been initialised	312	This returns the "default" event loop object, which is what you should
309	yet and return it. If the default loop could not be initialised, returns	313	normally use when you just need "the event loop". Event loop objects and
310	false. If it already was initialised it simply returns it (and ignores the	314	the C<flags> parameter are described in more detail in the entry for
311	flags. If that is troubling you, check C<ev_backend ()> afterwards).	315	C<ev_loop_new>.
		316
		317	If the default loop is already initialised then this function simply
		318	returns it (and ignores the flags. If that is troubling you, check
		319	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		320	flags, which should almost always be C<0>, unless the caller is also the
		321	one calling C<ev_run> or otherwise qualifies as "the main program".
312		322
313	If you don't know what event loop to use, use the one returned from this	323	If you don't know what event loop to use, use the one returned from this
314	function.	324	function (or via the C<EV_DEFAULT> macro).
315		325
316	Note that this function is I<not> thread-safe, so if you want to use it	326	Note that this function is I<not> thread-safe, so if you want to use it
317	from multiple threads, you have to lock (note also that this is unlikely,	327	from multiple threads, you have to employ some kind of mutex (note also
318	as loops cannot be shared easily between threads anyway).	328	that this case is unlikely, as loops cannot be shared easily between
		329	threads anyway).
319		330
320	The default loop is the only loop that can handle C<ev_signal> and	331	The default loop is the only loop that can handle C<ev_child> watchers,
321	C<ev_child> watchers, and to do this, it always registers a handler	332	and to do this, it always registers a handler for C<SIGCHLD>. If this is
322	for C<SIGCHLD>. If this is a problem for your application you can either	333	a problem for your application you can either create a dynamic loop with
323	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	334	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
324	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	335	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
325	C<ev_default_init>.	336
		337	Example: This is the most typical usage.
		338
		339	if (!ev_default_loop (0))
		340	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		341
		342	Example: Restrict libev to the select and poll backends, and do not allow
		343	environment settings to be taken into account:
		344
		345	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
		346
		347	=item struct ev_loop *ev_loop_new (unsigned int flags)
		348
		349	This will create and initialise a new event loop object. If the loop
		350	could not be initialised, returns false.
		351
		352	Note that this function I<is> thread-safe, and one common way to use
		353	libev with threads is indeed to create one loop per thread, and using the
		354	default loop in the "main" or "initial" thread.
326		355
327	The flags argument can be used to specify special behaviour or specific	356	The flags argument can be used to specify special behaviour or specific
328	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	357	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
329		358
330	The following flags are supported:	359	The following flags are supported:
…		…
345	useful to try out specific backends to test their performance, or to work	374	useful to try out specific backends to test their performance, or to work
346	around bugs.	375	around bugs.
347		376
348	=item C<EVFLAG_FORKCHECK>	377	=item C<EVFLAG_FORKCHECK>
349		378
350	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	379	Instead of calling C<ev_loop_fork> manually after a fork, you can also
351	a fork, you can also make libev check for a fork in each iteration by	380	make libev check for a fork in each iteration by enabling this flag.
352	enabling this flag.
353		381
354	This works by calling C<getpid ()> on every iteration of the loop,	382	This works by calling C<getpid ()> on every iteration of the loop,
355	and thus this might slow down your event loop if you do a lot of loop	383	and thus this might slow down your event loop if you do a lot of loop
356	iterations and little real work, but is usually not noticeable (on my	384	iterations and little real work, but is usually not noticeable (on my
357	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	385	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
…		…
439	of course I<doesn't>, and epoll just loves to report events for totally	467	of course I<doesn't>, and epoll just loves to report events for totally
440	I<different> file descriptors (even already closed ones, so one cannot	468	I<different> file descriptors (even already closed ones, so one cannot
441	even remove them from the set) than registered in the set (especially	469	even remove them from the set) than registered in the set (especially
442	on SMP systems). Libev tries to counter these spurious notifications by	470	on SMP systems). Libev tries to counter these spurious notifications by
443	employing an additional generation counter and comparing that against the	471	employing an additional generation counter and comparing that against the
444	events to filter out spurious ones, recreating the set when required.	472	events to filter out spurious ones, recreating the set when required. Last
		473	not least, it also refuses to work with some file descriptors which work
		474	perfectly fine with C<select> (files, many character devices...).
445		475
446	While stopping, setting and starting an I/O watcher in the same iteration	476	While stopping, setting and starting an I/O watcher in the same iteration
447	will result in some caching, there is still a system call per such	477	will result in some caching, there is still a system call per such
448	incident (because the same I<file descriptor> could point to a different	478	incident (because the same I<file descriptor> could point to a different
449	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	479	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
547	If one or more of the backend flags are or'ed into the flags value,	577	If one or more of the backend flags are or'ed into the flags value,
548	then only these backends will be tried (in the reverse order as listed	578	then only these backends will be tried (in the reverse order as listed
549	here). If none are specified, all backends in C<ev_recommended_backends	579	here). If none are specified, all backends in C<ev_recommended_backends
550	()> will be tried.	580	()> will be tried.
551		581
552	Example: This is the most typical usage.
553
554	if (!ev_default_loop (0))
555	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
556
557	Example: Restrict libev to the select and poll backends, and do not allow
558	environment settings to be taken into account:
559
560	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
561
562	Example: Use whatever libev has to offer, but make sure that kqueue is
563	used if available (warning, breaks stuff, best use only with your own
564	private event loop and only if you know the OS supports your types of
565	fds):
566
567	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
568
569	=item struct ev_loop *ev_loop_new (unsigned int flags)
570
571	Similar to C<ev_default_loop>, but always creates a new event loop that is
572	always distinct from the default loop. Unlike the default loop, it cannot
573	handle signal and child watchers, and attempts to do so will be greeted by
574	undefined behaviour (or a failed assertion if assertions are enabled).
575
576	Note that this function I<is> thread-safe, and the recommended 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.	582	Example: Try to create a event loop that uses epoll and nothing else.
581		583
582	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
583	if (!epoller)	585	if (!epoller)
584	fatal ("no epoll found here, maybe it hides under your chair");	586	fatal ("no epoll found here, maybe it hides under your chair");
585		587
		588	Example: Use whatever libev has to offer, but make sure that kqueue is
		589	used if available.
		590
		591	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
		592
586	=item ev_default_destroy ()	593	=item ev_loop_destroy (loop)
587		594
588	Destroys the default loop again (frees all memory and kernel state	595	Destroys an event loop object (frees all memory and kernel state
589	etc.). None of the active event watchers will be stopped in the normal	596	etc.). None of the active event watchers will be stopped in the normal
590	sense, so e.g. C<ev_is_active> might still return true. It is your	597	sense, so e.g. C<ev_is_active> might still return true. It is your
591	responsibility to either stop all watchers cleanly yourself I<before>	598	responsibility to either stop all watchers cleanly yourself I<before>
592	calling this function, or cope with the fact afterwards (which is usually	599	calling this function, or cope with the fact afterwards (which is usually
593	the easiest thing, you can just ignore the watchers and/or C<free ()> them	600	the easiest thing, you can just ignore the watchers and/or C<free ()> them
…		…
595		602
596	Note that certain global state, such as signal state (and installed signal	603	Note that certain global state, such as signal state (and installed signal
597	handlers), will not be freed by this function, and related watchers (such	604	handlers), will not be freed by this function, and related watchers (such
598	as signal and child watchers) would need to be stopped manually.	605	as signal and child watchers) would need to be stopped manually.
599		606
600	In general it is not advisable to call this function except in the	607	This function is normally used on loop objects allocated by
601	rare occasion where you really need to free e.g. the signal handling	608	C<ev_loop_new>, but it can also be used on the default loop returned by
		609	C<ev_default_loop>, in which case it is not thread-safe.
		610
		611	Note that it is not advisable to call this function on the default loop
		612	except in the rare occasion where you really need to free it's resources.
602	pipe fds. If you need dynamically allocated loops it is better to use	613	If you need dynamically allocated loops it is better to use C<ev_loop_new>
603	C<ev_loop_new> and C<ev_loop_destroy>.	614	and C<ev_loop_destroy>.
604		615
605	=item ev_loop_destroy (loop)	616	=item ev_loop_fork (loop)
606		617
607	Like C<ev_default_destroy>, but destroys an event loop created by an
608	earlier call to C<ev_loop_new>.
609
610	=item ev_default_fork ()
611
612	This function sets a flag that causes subsequent C<ev_loop> iterations	618	This function sets a flag that causes subsequent C<ev_run> iterations to
613	to reinitialise the kernel state for backends that have one. Despite the	619	reinitialise the kernel state for backends that have one. Despite the
614	name, you can call it anytime, but it makes most sense after forking, in	620	name, you can call it anytime, but it makes most sense after forking, in
615	the child process (or both child and parent, but that again makes little	621	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
616	sense). You I<must> call it in the child before using any of the libev	622	child before resuming or calling C<ev_run>.
617	functions, and it will only take effect at the next C<ev_loop> iteration.	623
		624	Again, you I<have> to call it on I<any> loop that you want to re-use after
		625	a fork, I<even if you do not plan to use the loop in the parent>. This is
		626	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
		627	during fork.
618		628
619	On the other hand, you only need to call this function in the child	629	On the other hand, you only need to call this function in the child
620	process if and only if you want to use the event library in the child. If	630	process if and only if you want to use the event loop in the child. If
621	you just fork+exec, you don't have to call it at all.	631	you just fork+exec or create a new loop in the child, you don't have to
		632	call it at all (in fact, C<epoll> is so badly broken that it makes a
		633	difference, but libev will usually detect this case on its own and do a
		634	costly reset of the backend).
622		635
623	The function itself is quite fast and it's usually not a problem to call	636	The function itself is quite fast and it's usually not a problem to call
624	it just in case after a fork. To make this easy, the function will fit in	637	it just in case after a fork.
625	quite nicely into a call to C<pthread_atfork>:
626		638
		639	Example: Automate calling C<ev_loop_fork> on the default loop when
		640	using pthreads.
		641
		642	static void
		643	post_fork_child (void)
		644	{
		645	ev_loop_fork (EV_DEFAULT);
		646	}
		647
		648	...
627	pthread_atfork (0, 0, ev_default_fork);	649	pthread_atfork (0, 0, post_fork_child);
628
629	=item ev_loop_fork (loop)
630
631	Like C<ev_default_fork>, but acts on an event loop created by
632	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
633	after fork that you want to re-use in the child, and how you do this is
634	entirely your own problem.
635		650
636	=item int ev_is_default_loop (loop)	651	=item int ev_is_default_loop (loop)
637		652
638	Returns true when the given loop is, in fact, the default loop, and false	653	Returns true when the given loop is, in fact, the default loop, and false
639	otherwise.	654	otherwise.
640		655
641	=item unsigned int ev_loop_count (loop)	656	=item unsigned int ev_iteration (loop)
642		657
643	Returns the count of loop iterations for the loop, which is identical to	658	Returns the current iteration count for the event loop, which is identical
644	the number of times libev did poll for new events. It starts at C<0> and	659	to the number of times libev did poll for new events. It starts at C<0>
645	happily wraps around with enough iterations.	660	and happily wraps around with enough iterations.
646		661
647	This value can sometimes be useful as a generation counter of sorts (it	662	This value can sometimes be useful as a generation counter of sorts (it
648	"ticks" the number of loop iterations), as it roughly corresponds with	663	"ticks" the number of loop iterations), as it roughly corresponds with
649	C<ev_prepare> and C<ev_check> calls.	664	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		665	prepare and check phases.
650		666
651	=item unsigned int ev_loop_depth (loop)	667	=item unsigned int ev_depth (loop)
652		668
653	Returns the number of times C<ev_loop> was entered minus the number of	669	Returns the number of times C<ev_run> was entered minus the number of
654	times C<ev_loop> was exited, in other words, the recursion depth.	670	times C<ev_run> was exited, in other words, the recursion depth.
655		671
656	Outside C<ev_loop>, this number is zero. In a callback, this number is	672	Outside C<ev_run>, this number is zero. In a callback, this number is
657	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	673	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
658	in which case it is higher.	674	in which case it is higher.
659		675
660	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	676	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
661	etc.), doesn't count as exit.	677	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		678	ungentleman-like behaviour unless it's really convenient.
662		679
663	=item unsigned int ev_backend (loop)	680	=item unsigned int ev_backend (loop)
664		681
665	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	682	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
666	use.	683	use.
…		…
675		692
676	=item ev_now_update (loop)	693	=item ev_now_update (loop)
677		694
678	Establishes the current time by querying the kernel, updating the time	695	Establishes the current time by querying the kernel, updating the time
679	returned by C<ev_now ()> in the progress. This is a costly operation and	696	returned by C<ev_now ()> in the progress. This is a costly operation and
680	is usually done automatically within C<ev_loop ()>.	697	is usually done automatically within C<ev_run ()>.
681		698
682	This function is rarely useful, but when some event callback runs for a	699	This function is rarely useful, but when some event callback runs for a
683	very long time without entering the event loop, updating libev's idea of	700	very long time without entering the event loop, updating libev's idea of
684	the current time is a good idea.	701	the current time is a good idea.
685		702
…		…
687		704
688	=item ev_suspend (loop)	705	=item ev_suspend (loop)
689		706
690	=item ev_resume (loop)	707	=item ev_resume (loop)
691		708
692	These two functions suspend and resume a loop, for use when the loop is	709	These two functions suspend and resume an event loop, for use when the
693	not used for a while and timeouts should not be processed.	710	loop is not used for a while and timeouts should not be processed.
694		711
695	A typical use case would be an interactive program such as a game: When	712	A typical use case would be an interactive program such as a game: When
696	the user presses C<^Z> to suspend the game and resumes it an hour later it	713	the user presses C<^Z> to suspend the game and resumes it an hour later it
697	would be best to handle timeouts as if no time had actually passed while	714	would be best to handle timeouts as if no time had actually passed while
698	the program was suspended. This can be achieved by calling C<ev_suspend>	715	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
700	C<ev_resume> directly afterwards to resume timer processing.	717	C<ev_resume> directly afterwards to resume timer processing.
701		718
702	Effectively, all C<ev_timer> watchers will be delayed by the time spend	719	Effectively, all C<ev_timer> watchers will be delayed by the time spend
703	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	720	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
704	will be rescheduled (that is, they will lose any events that would have	721	will be rescheduled (that is, they will lose any events that would have
705	occured while suspended).	722	occurred while suspended).
706		723
707	After calling C<ev_suspend> you B<must not> call I<any> function on the	724	After calling C<ev_suspend> you B<must not> call I<any> function on the
708	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	725	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
709	without a previous call to C<ev_suspend>.	726	without a previous call to C<ev_suspend>.
710		727
711	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	728	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
712	event loop time (see C<ev_now_update>).	729	event loop time (see C<ev_now_update>).
713		730
714	=item ev_loop (loop, int flags)	731	=item ev_run (loop, int flags)
715		732
716	Finally, this is it, the event handler. This function usually is called	733	Finally, this is it, the event handler. This function usually is called
717	after you have initialised all your watchers and you want to start	734	after you have initialised all your watchers and you want to start
718	handling events.	735	handling events. It will ask the operating system for any new events, call
		736	the watcher callbacks, an then repeat the whole process indefinitely: This
		737	is why event loops are called I<loops>.
719		738
720	If the flags argument is specified as C<0>, it will not return until	739	If the flags argument is specified as C<0>, it will keep handling events
721	either no event watchers are active anymore or C<ev_unloop> was called.	740	until either no event watchers are active anymore or C<ev_break> was
		741	called.
722		742
723	Please note that an explicit C<ev_unloop> is usually better than	743	Please note that an explicit C<ev_break> is usually better than
724	relying on all watchers to be stopped when deciding when a program has	744	relying on all watchers to be stopped when deciding when a program has
725	finished (especially in interactive programs), but having a program	745	finished (especially in interactive programs), but having a program
726	that automatically loops as long as it has to and no longer by virtue	746	that automatically loops as long as it has to and no longer by virtue
727	of relying on its watchers stopping correctly, that is truly a thing of	747	of relying on its watchers stopping correctly, that is truly a thing of
728	beauty.	748	beauty.
729		749
730	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	750	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
731	those events and any already outstanding ones, but will not block your	751	those events and any already outstanding ones, but will not wait and
732	process in case there are no events and will return after one iteration of	752	block your process in case there are no events and will return after one
733	the loop.	753	iteration of the loop. This is sometimes useful to poll and handle new
		754	events while doing lengthy calculations, to keep the program responsive.
734		755
735	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	756	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
736	necessary) and will handle those and any already outstanding ones. It	757	necessary) and will handle those and any already outstanding ones. It
737	will block your process until at least one new event arrives (which could	758	will block your process until at least one new event arrives (which could
738	be an event internal to libev itself, so there is no guarantee that a	759	be an event internal to libev itself, so there is no guarantee that a
739	user-registered callback will be called), and will return after one	760	user-registered callback will be called), and will return after one
740	iteration of the loop.	761	iteration of the loop.
741		762
742	This is useful if you are waiting for some external event in conjunction	763	This is useful if you are waiting for some external event in conjunction
743	with something not expressible using other libev watchers (i.e. "roll your	764	with something not expressible using other libev watchers (i.e. "roll your
744	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	765	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
745	usually a better approach for this kind of thing.	766	usually a better approach for this kind of thing.
746		767
747	Here are the gory details of what C<ev_loop> does:	768	Here are the gory details of what C<ev_run> does:
748		769
		770	- Increment loop depth.
		771	- Reset the ev_break status.
749	- Before the first iteration, call any pending watchers.	772	- Before the first iteration, call any pending watchers.
		773	LOOP:
750	* If EVFLAG_FORKCHECK was used, check for a fork.	774	- If EVFLAG_FORKCHECK was used, check for a fork.
751	- If a fork was detected (by any means), queue and call all fork watchers.	775	- If a fork was detected (by any means), queue and call all fork watchers.
752	- Queue and call all prepare watchers.	776	- Queue and call all prepare watchers.
		777	- If ev_break was called, goto FINISH.
753	- If we have been forked, detach and recreate the kernel state	778	- If we have been forked, detach and recreate the kernel state
754	as to not disturb the other process.	779	as to not disturb the other process.
755	- Update the kernel state with all outstanding changes.	780	- Update the kernel state with all outstanding changes.
756	- Update the "event loop time" (ev_now ()).	781	- Update the "event loop time" (ev_now ()).
757	- Calculate for how long to sleep or block, if at all	782	- Calculate for how long to sleep or block, if at all
758	(active idle watchers, EVLOOP_NONBLOCK or not having	783	(active idle watchers, EVRUN_NOWAIT or not having
759	any active watchers at all will result in not sleeping).	784	any active watchers at all will result in not sleeping).
760	- Sleep if the I/O and timer collect interval say so.	785	- Sleep if the I/O and timer collect interval say so.
		786	- Increment loop iteration counter.
761	- Block the process, waiting for any events.	787	- Block the process, waiting for any events.
762	- Queue all outstanding I/O (fd) events.	788	- Queue all outstanding I/O (fd) events.
763	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	789	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
764	- Queue all expired timers.	790	- Queue all expired timers.
765	- Queue all expired periodics.	791	- Queue all expired periodics.
766	- Unless any events are pending now, queue all idle watchers.	792	- Queue all idle watchers with priority higher than that of pending events.
767	- Queue all check watchers.	793	- Queue all check watchers.
768	- Call all queued watchers in reverse order (i.e. check watchers first).	794	- Call all queued watchers in reverse order (i.e. check watchers first).
769	Signals and child watchers are implemented as I/O watchers, and will	795	Signals and child watchers are implemented as I/O watchers, and will
770	be handled here by queueing them when their watcher gets executed.	796	be handled here by queueing them when their watcher gets executed.
771	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	797	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
772	were used, or there are no active watchers, return, otherwise	798	were used, or there are no active watchers, goto FINISH, otherwise
773	continue with step *.	799	continue with step LOOP.
		800	FINISH:
		801	- Reset the ev_break status iff it was EVBREAK_ONE.
		802	- Decrement the loop depth.
		803	- Return.
774		804
775	Example: Queue some jobs and then loop until no events are outstanding	805	Example: Queue some jobs and then loop until no events are outstanding
776	anymore.	806	anymore.
777		807
778	... queue jobs here, make sure they register event watchers as long	808	... queue jobs here, make sure they register event watchers as long
779	... as they still have work to do (even an idle watcher will do..)	809	... as they still have work to do (even an idle watcher will do..)
780	ev_loop (my_loop, 0);	810	ev_run (my_loop, 0);
781	... jobs done or somebody called unloop. yeah!	811	... jobs done or somebody called unloop. yeah!
782		812
783	=item ev_unloop (loop, how)	813	=item ev_break (loop, how)
784		814
785	Can be used to make a call to C<ev_loop> return early (but only after it	815	Can be used to make a call to C<ev_run> return early (but only after it
786	has processed all outstanding events). The C<how> argument must be either	816	has processed all outstanding events). The C<how> argument must be either
787	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	817	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
788	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	818	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
789		819
790	This "unloop state" will be cleared when entering C<ev_loop> again.	820	This "unloop state" will be cleared when entering C<ev_run> again.
791		821
792	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	822	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
793		823
794	=item ev_ref (loop)	824	=item ev_ref (loop)
795		825
796	=item ev_unref (loop)	826	=item ev_unref (loop)
797		827
798	Ref/unref can be used to add or remove a reference count on the event	828	Ref/unref can be used to add or remove a reference count on the event
799	loop: Every watcher keeps one reference, and as long as the reference	829	loop: Every watcher keeps one reference, and as long as the reference
800	count is nonzero, C<ev_loop> will not return on its own.	830	count is nonzero, C<ev_run> will not return on its own.
801		831
802	This is useful when you have a watcher that you never intend to	832	This is useful when you have a watcher that you never intend to
803	unregister, but that nevertheless should not keep C<ev_loop> from	833	unregister, but that nevertheless should not keep C<ev_run> from
804	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>	834	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
805	before stopping it.	835	before stopping it.
806		836
807	As an example, libev itself uses this for its internal signal pipe: It	837	As an example, libev itself uses this for its internal signal pipe: It
808	is not visible to the libev user and should not keep C<ev_loop> from	838	is not visible to the libev user and should not keep C<ev_run> from
809	exiting if no event watchers registered by it are active. It is also an	839	exiting if no event watchers registered by it are active. It is also an
810	excellent way to do this for generic recurring timers or from within	840	excellent way to do this for generic recurring timers or from within
811	third-party libraries. Just remember to I<unref after start> and I<ref	841	third-party libraries. Just remember to I<unref after start> and I<ref
812	before stop> (but only if the watcher wasn't active before, or was active	842	before stop> (but only if the watcher wasn't active before, or was active
813	before, respectively. Note also that libev might stop watchers itself	843	before, respectively. Note also that libev might stop watchers itself
814	(e.g. non-repeating timers) in which case you have to C<ev_ref>	844	(e.g. non-repeating timers) in which case you have to C<ev_ref>
815	in the callback).	845	in the callback).
816		846
817	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	847	Example: Create a signal watcher, but keep it from keeping C<ev_run>
818	running when nothing else is active.	848	running when nothing else is active.
819		849
820	ev_signal exitsig;	850	ev_signal exitsig;
821	ev_signal_init (&exitsig, sig_cb, SIGINT);	851	ev_signal_init (&exitsig, sig_cb, SIGINT);
822	ev_signal_start (loop, &exitsig);	852	ev_signal_start (loop, &exitsig);
…		…
867	usually doesn't make much sense to set it to a lower value than C<0.01>,	897	usually doesn't make much sense to set it to a lower value than C<0.01>,
868	as this approaches the timing granularity of most systems. Note that if	898	as this approaches the timing granularity of most systems. Note that if
869	you do transactions with the outside world and you can't increase the	899	you do transactions with the outside world and you can't increase the
870	parallelity, then this setting will limit your transaction rate (if you	900	parallelity, then this setting will limit your transaction rate (if you
871	need to poll once per transaction and the I/O collect interval is 0.01,	901	need to poll once per transaction and the I/O collect interval is 0.01,
872	then you can't do more than 100 transations per second).	902	then you can't do more than 100 transactions per second).
873		903
874	Setting the I<timeout collect interval> can improve the opportunity for	904	Setting the I<timeout collect interval> can improve the opportunity for
875	saving power, as the program will "bundle" timer callback invocations that	905	saving power, as the program will "bundle" timer callback invocations that
876	are "near" in time together, by delaying some, thus reducing the number of	906	are "near" in time together, by delaying some, thus reducing the number of
877	times the process sleeps and wakes up again. Another useful technique to	907	times the process sleeps and wakes up again. Another useful technique to
…		…
885	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	915	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
886		916
887	=item ev_invoke_pending (loop)	917	=item ev_invoke_pending (loop)
888		918
889	This call will simply invoke all pending watchers while resetting their	919	This call will simply invoke all pending watchers while resetting their
890	pending state. Normally, C<ev_loop> does this automatically when required,	920	pending state. Normally, C<ev_run> does this automatically when required,
891	but when overriding the invoke callback this call comes handy.	921	but when overriding the invoke callback this call comes handy. This
		922	function can be invoked from a watcher - this can be useful for example
		923	when you want to do some lengthy calculation and want to pass further
		924	event handling to another thread (you still have to make sure only one
		925	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
892		926
893	=item int ev_pending_count (loop)	927	=item int ev_pending_count (loop)
894		928
895	Returns the number of pending watchers - zero indicates that no watchers	929	Returns the number of pending watchers - zero indicates that no watchers
896	are pending.	930	are pending.
897		931
898	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	932	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
899		933
900	This overrides the invoke pending functionality of the loop: Instead of	934	This overrides the invoke pending functionality of the loop: Instead of
901	invoking all pending watchers when there are any, C<ev_loop> will call	935	invoking all pending watchers when there are any, C<ev_run> will call
902	this callback instead. This is useful, for example, when you want to	936	this callback instead. This is useful, for example, when you want to
903	invoke the actual watchers inside another context (another thread etc.).	937	invoke the actual watchers inside another context (another thread etc.).
904		938
905	If you want to reset the callback, use C<ev_invoke_pending> as new	939	If you want to reset the callback, use C<ev_invoke_pending> as new
906	callback.	940	callback.
…		…
909		943
910	Sometimes you want to share the same loop between multiple threads. This	944	Sometimes you want to share the same loop between multiple threads. This
911	can be done relatively simply by putting mutex_lock/unlock calls around	945	can be done relatively simply by putting mutex_lock/unlock calls around
912	each call to a libev function.	946	each call to a libev function.
913		947
914	However, C<ev_loop> can run an indefinite time, so it is not feasible to	948	However, C<ev_run> can run an indefinite time, so it is not feasible
915	wait for it to return. One way around this is to wake up the loop via	949	to wait for it to return. One way around this is to wake up the event
916	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	950	loop via C<ev_break> and C<av_async_send>, another way is to set these
917	and I<acquire> callbacks on the loop.	951	I<release> and I<acquire> callbacks on the loop.
918		952
919	When set, then C<release> will be called just before the thread is	953	When set, then C<release> will be called just before the thread is
920	suspended waiting for new events, and C<acquire> is called just	954	suspended waiting for new events, and C<acquire> is called just
921	afterwards.	955	afterwards.
922		956
…		…
925		959
926	While event loop modifications are allowed between invocations of	960	While event loop modifications are allowed between invocations of
927	C<release> and C<acquire> (that's their only purpose after all), no	961	C<release> and C<acquire> (that's their only purpose after all), no
928	modifications done will affect the event loop, i.e. adding watchers will	962	modifications done will affect the event loop, i.e. adding watchers will
929	have no effect on the set of file descriptors being watched, or the time	963	have no effect on the set of file descriptors being watched, or the time
930	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	964	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
931	to take note of any changes you made.	965	to take note of any changes you made.
932		966
933	In theory, threads executing C<ev_loop> will be async-cancel safe between	967	In theory, threads executing C<ev_run> will be async-cancel safe between
934	invocations of C<release> and C<acquire>.	968	invocations of C<release> and C<acquire>.
935		969
936	See also the locking example in the C<THREADS> section later in this	970	See also the locking example in the C<THREADS> section later in this
937	document.	971	document.
938		972
…		…
947	These two functions can be used to associate arbitrary data with a loop,	981	These two functions can be used to associate arbitrary data with a loop,
948	and are intended solely for the C<invoke_pending_cb>, C<release> and	982	and are intended solely for the C<invoke_pending_cb>, C<release> and
949	C<acquire> callbacks described above, but of course can be (ab-)used for	983	C<acquire> callbacks described above, but of course can be (ab-)used for
950	any other purpose as well.	984	any other purpose as well.
951		985
952	=item ev_loop_verify (loop)	986	=item ev_verify (loop)
953		987
954	This function only does something when C<EV_VERIFY> support has been	988	This function only does something when C<EV_VERIFY> support has been
955	compiled in, which is the default for non-minimal builds. It tries to go	989	compiled in, which is the default for non-minimal builds. It tries to go
956	through all internal structures and checks them for validity. If anything	990	through all internal structures and checks them for validity. If anything
957	is found to be inconsistent, it will print an error message to standard	991	is found to be inconsistent, it will print an error message to standard
…		…
968		1002
969	In the following description, uppercase C<TYPE> in names stands for the	1003	In the following description, uppercase C<TYPE> in names stands for the
970	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1004	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
971	watchers and C<ev_io_start> for I/O watchers.	1005	watchers and C<ev_io_start> for I/O watchers.
972		1006
973	A watcher is a structure that you create and register to record your	1007	A watcher is an opaque structure that you allocate and register to record
974	interest in some event. For instance, if you want to wait for STDIN to	1008	your interest in some event. To make a concrete example, imagine you want
975	become readable, you would create an C<ev_io> watcher for that:	1009	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1010	for that:
976		1011
977	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1012	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
978	{	1013	{
979	ev_io_stop (w);	1014	ev_io_stop (w);
980	ev_unloop (loop, EVUNLOOP_ALL);	1015	ev_break (loop, EVBREAK_ALL);
981	}	1016	}
982		1017
983	struct ev_loop *loop = ev_default_loop (0);	1018	struct ev_loop *loop = ev_default_loop (0);
984		1019
985	ev_io stdin_watcher;	1020	ev_io stdin_watcher;
986		1021
987	ev_init (&stdin_watcher, my_cb);	1022	ev_init (&stdin_watcher, my_cb);
988	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1023	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
989	ev_io_start (loop, &stdin_watcher);	1024	ev_io_start (loop, &stdin_watcher);
990		1025
991	ev_loop (loop, 0);	1026	ev_run (loop, 0);
992		1027
993	As you can see, you are responsible for allocating the memory for your	1028	As you can see, you are responsible for allocating the memory for your
994	watcher structures (and it is I<usually> a bad idea to do this on the	1029	watcher structures (and it is I<usually> a bad idea to do this on the
995	stack).	1030	stack).
996		1031
997	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1032	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
998	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1033	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
999		1034
1000	Each watcher structure must be initialised by a call to C<ev_init	1035	Each watcher structure must be initialised by a call to C<ev_init (watcher
1001	(watcher *, callback)>, which expects a callback to be provided. This	1036	*, callback)>, which expects a callback to be provided. This callback is
1002	callback gets invoked each time the event occurs (or, in the case of I/O	1037	invoked each time the event occurs (or, in the case of I/O watchers, each
1003	watchers, each time the event loop detects that the file descriptor given	1038	time the event loop detects that the file descriptor given is readable
1004	is readable and/or writable).	1039	and/or writable).
1005		1040
1006	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1041	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1007	macro to configure it, with arguments specific to the watcher type. There	1042	macro to configure it, with arguments specific to the watcher type. There
1008	is also a macro to combine initialisation and setting in one call: C<<	1043	is also a macro to combine initialisation and setting in one call: C<<
1009	ev_TYPE_init (watcher *, callback, ...) >>.	1044	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1032	=item C<EV_WRITE>	1067	=item C<EV_WRITE>
1033		1068
1034	The file descriptor in the C<ev_io> watcher has become readable and/or	1069	The file descriptor in the C<ev_io> watcher has become readable and/or
1035	writable.	1070	writable.
1036		1071
1037	=item C<EV_TIMEOUT>	1072	=item C<EV_TIMER>
1038		1073
1039	The C<ev_timer> watcher has timed out.	1074	The C<ev_timer> watcher has timed out.
1040		1075
1041	=item C<EV_PERIODIC>	1076	=item C<EV_PERIODIC>
1042		1077
…		…
1060		1095
1061	=item C<EV_PREPARE>	1096	=item C<EV_PREPARE>
1062		1097
1063	=item C<EV_CHECK>	1098	=item C<EV_CHECK>
1064		1099
1065	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1100	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1066	to gather new events, and all C<ev_check> watchers are invoked just after	1101	to gather new events, and all C<ev_check> watchers are invoked just after
1067	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1102	C<ev_run> has gathered them, but before it invokes any callbacks for any
1068	received events. Callbacks of both watcher types can start and stop as	1103	received events. Callbacks of both watcher types can start and stop as
1069	many watchers as they want, and all of them will be taken into account	1104	many watchers as they want, and all of them will be taken into account
1070	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1105	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1071	C<ev_loop> from blocking).	1106	C<ev_run> from blocking).
1072		1107
1073	=item C<EV_EMBED>	1108	=item C<EV_EMBED>
1074		1109
1075	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1110	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1076		1111
1077	=item C<EV_FORK>	1112	=item C<EV_FORK>
1078		1113
1079	The event loop has been resumed in the child process after fork (see	1114	The event loop has been resumed in the child process after fork (see
1080	C<ev_fork>).	1115	C<ev_fork>).
		1116
		1117	=item C<EV_CLEANUP>
		1118
		1119	The event loop is about to be destroyed (see C<ev_cleanup>).
1081		1120
1082	=item C<EV_ASYNC>	1121	=item C<EV_ASYNC>
1083		1122
1084	The given async watcher has been asynchronously notified (see C<ev_async>).	1123	The given async watcher has been asynchronously notified (see C<ev_async>).
1085		1124
…		…
1104	example it might indicate that a fd is readable or writable, and if your	1143	example it might indicate that a fd is readable or writable, and if your
1105	callbacks is well-written it can just attempt the operation and cope with	1144	callbacks is well-written it can just attempt the operation and cope with
1106	the error from read() or write(). This will not work in multi-threaded	1145	the error from read() or write(). This will not work in multi-threaded
1107	programs, though, as the fd could already be closed and reused for another	1146	programs, though, as the fd could already be closed and reused for another
1108	thing, so beware.	1147	thing, so beware.
		1148
		1149	=back
		1150
		1151	=head2 WATCHER STATES
		1152
		1153	There are various watcher states mentioned throughout this manual -
		1154	active, pending and so on. In this section these states and the rules to
		1155	transition between them will be described in more detail - and while these
		1156	rules might look complicated, they usually do "the right thing".
		1157
		1158	=over 4
		1159
		1160	=item initialiased
		1161
		1162	Before a watcher can be registered with the event looop it has to be
		1163	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1164	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1165
		1166	In this state it is simply some block of memory that is suitable for use
		1167	in an event loop. It can be moved around, freed, reused etc. at will.
		1168
		1169	=item started/running/active
		1170
		1171	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1172	property of the event loop, and is actively waiting for events. While in
		1173	this state it cannot be accessed (except in a few documented ways), moved,
		1174	freed or anything else - the only legal thing is to keep a pointer to it,
		1175	and call libev functions on it that are documented to work on active watchers.
		1176
		1177	=item pending
		1178
		1179	If a watcher is active and libev determines that an event it is interested
		1180	in has occurred (such as a timer expiring), it will become pending. It will
		1181	stay in this pending state until either it is stopped or its callback is
		1182	about to be invoked, so it is not normally pending inside the watcher
		1183	callback.
		1184
		1185	The watcher might or might not be active while it is pending (for example,
		1186	an expired non-repeating timer can be pending but no longer active). If it
		1187	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1188	but it is still property of the event loop at this time, so cannot be
		1189	moved, freed or reused. And if it is active the rules described in the
		1190	previous item still apply.
		1191
		1192	It is also possible to feed an event on a watcher that is not active (e.g.
		1193	via C<ev_feed_event>), in which case it becomes pending without being
		1194	active.
		1195
		1196	=item stopped
		1197
		1198	A watcher can be stopped implicitly by libev (in which case it might still
		1199	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1200	latter will clear any pending state the watcher might be in, regardless
		1201	of whether it was active or not, so stopping a watcher explicitly before
		1202	freeing it is often a good idea.
		1203
		1204	While stopped (and not pending) the watcher is essentially in the
		1205	initialised state, that is it can be reused, moved, modified in any way
		1206	you wish.
1109		1207
1110	=back	1208	=back
1111		1209
1112	=head2 GENERIC WATCHER FUNCTIONS	1210	=head2 GENERIC WATCHER FUNCTIONS
1113		1211
…		…
1375		1473
1376	For example, to emulate how many other event libraries handle priorities,	1474	For example, to emulate how many other event libraries handle priorities,
1377	you can associate an C<ev_idle> watcher to each such watcher, and in	1475	you can associate an C<ev_idle> watcher to each such watcher, and in
1378	the normal watcher callback, you just start the idle watcher. The real	1476	the normal watcher callback, you just start the idle watcher. The real
1379	processing is done in the idle watcher callback. This causes libev to	1477	processing is done in the idle watcher callback. This causes libev to
1380	continously poll and process kernel event data for the watcher, but when	1478	continuously poll and process kernel event data for the watcher, but when
1381	the lock-out case is known to be rare (which in turn is rare :), this is	1479	the lock-out case is known to be rare (which in turn is rare :), this is
1382	workable.	1480	workable.
1383		1481
1384	Usually, however, the lock-out model implemented that way will perform	1482	Usually, however, the lock-out model implemented that way will perform
1385	miserably under the type of load it was designed to handle. In that case,	1483	miserably under the type of load it was designed to handle. In that case,
…		…
1399	{	1497	{
1400	// stop the I/O watcher, we received the event, but	1498	// stop the I/O watcher, we received the event, but
1401	// are not yet ready to handle it.	1499	// are not yet ready to handle it.
1402	ev_io_stop (EV_A_ w);	1500	ev_io_stop (EV_A_ w);
1403		1501
1404	// start the idle watcher to ahndle the actual event.	1502	// start the idle watcher to handle the actual event.
1405	// it will not be executed as long as other watchers	1503	// it will not be executed as long as other watchers
1406	// with the default priority are receiving events.	1504	// with the default priority are receiving events.
1407	ev_idle_start (EV_A_ &idle);	1505	ev_idle_start (EV_A_ &idle);
1408	}	1506	}
1409		1507
…		…
1463		1561
1464	If you cannot use non-blocking mode, then force the use of a	1562	If you cannot use non-blocking mode, then force the use of a
1465	known-to-be-good backend (at the time of this writing, this includes only	1563	known-to-be-good backend (at the time of this writing, this includes only
1466	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1564	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1467	descriptors for which non-blocking operation makes no sense (such as	1565	descriptors for which non-blocking operation makes no sense (such as
1468	files) - libev doesn't guarentee any specific behaviour in that case.	1566	files) - libev doesn't guarantee any specific behaviour in that case.
1469		1567
1470	Another thing you have to watch out for is that it is quite easy to	1568	Another thing you have to watch out for is that it is quite easy to
1471	receive "spurious" readiness notifications, that is your callback might	1569	receive "spurious" readiness notifications, that is your callback might
1472	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1570	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1473	because there is no data. Not only are some backends known to create a	1571	because there is no data. Not only are some backends known to create a
…		…
1541	somewhere, as that would have given you a big clue).	1639	somewhere, as that would have given you a big clue).
1542		1640
1543	=head3 The special problem of accept()ing when you can't	1641	=head3 The special problem of accept()ing when you can't
1544		1642
1545	Many implementations of the POSIX C<accept> function (for example,	1643	Many implementations of the POSIX C<accept> function (for example,
1546	found in port-2004 Linux) have the peculiar behaviour of not removing a	1644	found in post-2004 Linux) have the peculiar behaviour of not removing a
1547	connection from the pending queue in all error cases.	1645	connection from the pending queue in all error cases.
1548		1646
1549	For example, larger servers often run out of file descriptors (because	1647	For example, larger servers often run out of file descriptors (because
1550	of resource limits), causing C<accept> to fail with C<ENFILE> but not	1648	of resource limits), causing C<accept> to fail with C<ENFILE> but not
1551	rejecting the connection, leading to libev signalling readiness on	1649	rejecting the connection, leading to libev signalling readiness on
…		…
1617	...	1715	...
1618	struct ev_loop *loop = ev_default_init (0);	1716	struct ev_loop *loop = ev_default_init (0);
1619	ev_io stdin_readable;	1717	ev_io stdin_readable;
1620	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1718	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1621	ev_io_start (loop, &stdin_readable);	1719	ev_io_start (loop, &stdin_readable);
1622	ev_loop (loop, 0);	1720	ev_run (loop, 0);
1623		1721
1624		1722
1625	=head2 C<ev_timer> - relative and optionally repeating timeouts	1723	=head2 C<ev_timer> - relative and optionally repeating timeouts
1626		1724
1627	Timer watchers are simple relative timers that generate an event after a	1725	Timer watchers are simple relative timers that generate an event after a
…		…
1636	The callback is guaranteed to be invoked only I<after> its timeout has	1734	The callback is guaranteed to be invoked only I<after> its timeout has
1637	passed (not I<at>, so on systems with very low-resolution clocks this	1735	passed (not I<at>, so on systems with very low-resolution clocks this
1638	might introduce a small delay). If multiple timers become ready during the	1736	might introduce a small delay). If multiple timers become ready during the
1639	same loop iteration then the ones with earlier time-out values are invoked	1737	same loop iteration then the ones with earlier time-out values are invoked
1640	before ones of the same priority with later time-out values (but this is	1738	before ones of the same priority with later time-out values (but this is
1641	no longer true when a callback calls C<ev_loop> recursively).	1739	no longer true when a callback calls C<ev_run> recursively).
1642		1740
1643	=head3 Be smart about timeouts	1741	=head3 Be smart about timeouts
1644		1742
1645	Many real-world problems involve some kind of timeout, usually for error	1743	Many real-world problems involve some kind of timeout, usually for error
1646	recovery. A typical example is an HTTP request - if the other side hangs,	1744	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1732	ev_tstamp timeout = last_activity + 60.;	1830	ev_tstamp timeout = last_activity + 60.;
1733		1831
1734	// if last_activity + 60. is older than now, we did time out	1832	// if last_activity + 60. is older than now, we did time out
1735	if (timeout < now)	1833	if (timeout < now)
1736	{	1834	{
1737	// timeout occured, take action	1835	// timeout occurred, take action
1738	}	1836	}
1739	else	1837	else
1740	{	1838	{
1741	// callback was invoked, but there was some activity, re-arm	1839	// callback was invoked, but there was some activity, re-arm
1742	// the watcher to fire in last_activity + 60, which is	1840	// the watcher to fire in last_activity + 60, which is
…		…
1764	to the current time (meaning we just have some activity :), then call the	1862	to the current time (meaning we just have some activity :), then call the
1765	callback, which will "do the right thing" and start the timer:	1863	callback, which will "do the right thing" and start the timer:
1766		1864
1767	ev_init (timer, callback);	1865	ev_init (timer, callback);
1768	last_activity = ev_now (loop);	1866	last_activity = ev_now (loop);
1769	callback (loop, timer, EV_TIMEOUT);	1867	callback (loop, timer, EV_TIMER);
1770		1868
1771	And when there is some activity, simply store the current time in	1869	And when there is some activity, simply store the current time in
1772	C<last_activity>, no libev calls at all:	1870	C<last_activity>, no libev calls at all:
1773		1871
1774	last_actiivty = ev_now (loop);	1872	last_activity = ev_now (loop);
1775		1873
1776	This technique is slightly more complex, but in most cases where the	1874	This technique is slightly more complex, but in most cases where the
1777	time-out is unlikely to be triggered, much more efficient.	1875	time-out is unlikely to be triggered, much more efficient.
1778		1876
1779	Changing the timeout is trivial as well (if it isn't hard-coded in the	1877	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1817		1915
1818	=head3 The special problem of time updates	1916	=head3 The special problem of time updates
1819		1917
1820	Establishing the current time is a costly operation (it usually takes at	1918	Establishing the current time is a costly operation (it usually takes at
1821	least two system calls): EV therefore updates its idea of the current	1919	least two system calls): EV therefore updates its idea of the current
1822	time only before and after C<ev_loop> collects new events, which causes a	1920	time only before and after C<ev_run> collects new events, which causes a
1823	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1921	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1824	lots of events in one iteration.	1922	lots of events in one iteration.
1825		1923
1826	The relative timeouts are calculated relative to the C<ev_now ()>	1924	The relative timeouts are calculated relative to the C<ev_now ()>
1827	time. This is usually the right thing as this timestamp refers to the time	1925	time. This is usually the right thing as this timestamp refers to the time
…		…
1944	}	2042	}
1945		2043
1946	ev_timer mytimer;	2044	ev_timer mytimer;
1947	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2045	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1948	ev_timer_again (&mytimer); /* start timer */	2046	ev_timer_again (&mytimer); /* start timer */
1949	ev_loop (loop, 0);	2047	ev_run (loop, 0);
1950		2048
1951	// and in some piece of code that gets executed on any "activity":	2049	// and in some piece of code that gets executed on any "activity":
1952	// reset the timeout to start ticking again at 10 seconds	2050	// reset the timeout to start ticking again at 10 seconds
1953	ev_timer_again (&mytimer);	2051	ev_timer_again (&mytimer);
1954		2052
…		…
1980		2078
1981	As with timers, the callback is guaranteed to be invoked only when the	2079	As with timers, the callback is guaranteed to be invoked only when the
1982	point in time where it is supposed to trigger has passed. If multiple	2080	point in time where it is supposed to trigger has passed. If multiple
1983	timers become ready during the same loop iteration then the ones with	2081	timers become ready during the same loop iteration then the ones with
1984	earlier time-out values are invoked before ones with later time-out values	2082	earlier time-out values are invoked before ones with later time-out values
1985	(but this is no longer true when a callback calls C<ev_loop> recursively).	2083	(but this is no longer true when a callback calls C<ev_run> recursively).
1986		2084
1987	=head3 Watcher-Specific Functions and Data Members	2085	=head3 Watcher-Specific Functions and Data Members
1988		2086
1989	=over 4	2087	=over 4
1990		2088
…		…
2118	Example: Call a callback every hour, or, more precisely, whenever the	2216	Example: Call a callback every hour, or, more precisely, whenever the
2119	system time is divisible by 3600. The callback invocation times have	2217	system time is divisible by 3600. The callback invocation times have
2120	potentially a lot of jitter, but good long-term stability.	2218	potentially a lot of jitter, but good long-term stability.
2121		2219
2122	static void	2220	static void
2123	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2221	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
2124	{	2222	{
2125	... its now a full hour (UTC, or TAI or whatever your clock follows)	2223	... its now a full hour (UTC, or TAI or whatever your clock follows)
2126	}	2224	}
2127		2225
2128	ev_periodic hourly_tick;	2226	ev_periodic hourly_tick;
…		…
2228	Example: Try to exit cleanly on SIGINT.	2326	Example: Try to exit cleanly on SIGINT.
2229		2327
2230	static void	2328	static void
2231	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2329	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2232	{	2330	{
2233	ev_unloop (loop, EVUNLOOP_ALL);	2331	ev_break (loop, EVBREAK_ALL);
2234	}	2332	}
2235		2333
2236	ev_signal signal_watcher;	2334	ev_signal signal_watcher;
2237	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2335	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2238	ev_signal_start (loop, &signal_watcher);	2336	ev_signal_start (loop, &signal_watcher);
…		…
2624		2722
2625	Prepare and check watchers are usually (but not always) used in pairs:	2723	Prepare and check watchers are usually (but not always) used in pairs:
2626	prepare watchers get invoked before the process blocks and check watchers	2724	prepare watchers get invoked before the process blocks and check watchers
2627	afterwards.	2725	afterwards.
2628		2726
2629	You I<must not> call C<ev_loop> or similar functions that enter	2727	You I<must not> call C<ev_run> or similar functions that enter
2630	the current event loop from either C<ev_prepare> or C<ev_check>	2728	the current event loop from either C<ev_prepare> or C<ev_check>
2631	watchers. Other loops than the current one are fine, however. The	2729	watchers. Other loops than the current one are fine, however. The
2632	rationale behind this is that you do not need to check for recursion in	2730	rationale behind this is that you do not need to check for recursion in
2633	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2731	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2634	C<ev_check> so if you have one watcher of each kind they will always be	2732	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2802		2900
2803	if (timeout >= 0)	2901	if (timeout >= 0)
2804	// create/start timer	2902	// create/start timer
2805		2903
2806	// poll	2904	// poll
2807	ev_loop (EV_A_ 0);	2905	ev_run (EV_A_ 0);
2808		2906
2809	// stop timer again	2907	// stop timer again
2810	if (timeout >= 0)	2908	if (timeout >= 0)
2811	ev_timer_stop (EV_A_ &to);	2909	ev_timer_stop (EV_A_ &to);
2812		2910
…		…
2890	if you do not want that, you need to temporarily stop the embed watcher).	2988	if you do not want that, you need to temporarily stop the embed watcher).
2891		2989
2892	=item ev_embed_sweep (loop, ev_embed *)	2990	=item ev_embed_sweep (loop, ev_embed *)
2893		2991
2894	Make a single, non-blocking sweep over the embedded loop. This works	2992	Make a single, non-blocking sweep over the embedded loop. This works
2895	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2993	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2896	appropriate way for embedded loops.	2994	appropriate way for embedded loops.
2897		2995
2898	=item struct ev_loop *other [read-only]	2996	=item struct ev_loop *other [read-only]
2899		2997
2900	The embedded event loop.	2998	The embedded event loop.
…		…
2960	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3058	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2961	handlers will be invoked, too, of course.	3059	handlers will be invoked, too, of course.
2962		3060
2963	=head3 The special problem of life after fork - how is it possible?	3061	=head3 The special problem of life after fork - how is it possible?
2964		3062
2965	Most uses of C<fork()> consist of forking, then some simple calls to ste	3063	Most uses of C<fork()> consist of forking, then some simple calls to set
2966	up/change the process environment, followed by a call to C<exec()>. This	3064	up/change the process environment, followed by a call to C<exec()>. This
2967	sequence should be handled by libev without any problems.	3065	sequence should be handled by libev without any problems.
2968		3066
2969	This changes when the application actually wants to do event handling	3067	This changes when the application actually wants to do event handling
2970	in the child, or both parent in child, in effect "continuing" after the	3068	in the child, or both parent in child, in effect "continuing" after the
…		…
2986	disadvantage of having to use multiple event loops (which do not support	3084	disadvantage of having to use multiple event loops (which do not support
2987	signal watchers).	3085	signal watchers).
2988		3086
2989	When this is not possible, or you want to use the default loop for	3087	When this is not possible, or you want to use the default loop for
2990	other reasons, then in the process that wants to start "fresh", call	3088	other reasons, then in the process that wants to start "fresh", call
2991	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3089	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2992	the default loop will "orphan" (not stop) all registered watchers, so you	3090	Destroying the default loop will "orphan" (not stop) all registered
2993	have to be careful not to execute code that modifies those watchers. Note	3091	watchers, so you have to be careful not to execute code that modifies
2994	also that in that case, you have to re-register any signal watchers.	3092	those watchers. Note also that in that case, you have to re-register any
		3093	signal watchers.
2995		3094
2996	=head3 Watcher-Specific Functions and Data Members	3095	=head3 Watcher-Specific Functions and Data Members
2997		3096
2998	=over 4	3097	=over 4
2999		3098
3000	=item ev_fork_init (ev_signal *, callback)	3099	=item ev_fork_init (ev_fork *, callback)
3001		3100
3002	Initialises and configures the fork watcher - it has no parameters of any	3101	Initialises and configures the fork watcher - it has no parameters of any
3003	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,	3102	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3004	believe me.	3103	really.
3005		3104
3006	=back	3105	=back
3007		3106
3008		3107
		3108	=head2 C<ev_cleanup> - even the best things end
		3109
		3110	Cleanup watchers are called just before the event loop is being destroyed
		3111	by a call to C<ev_loop_destroy>.
		3112
		3113	While there is no guarantee that the event loop gets destroyed, cleanup
		3114	watchers provide a convenient method to install cleanup hooks for your
		3115	program, worker threads and so on - you just to make sure to destroy the
		3116	loop when you want them to be invoked.
		3117
		3118	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3119	all other watchers, they do not keep a reference to the event loop (which
		3120	makes a lot of sense if you think about it). Like all other watchers, you
		3121	can call libev functions in the callback, except C<ev_cleanup_start>.
		3122
		3123	=head3 Watcher-Specific Functions and Data Members
		3124
		3125	=over 4
		3126
		3127	=item ev_cleanup_init (ev_cleanup *, callback)
		3128
		3129	Initialises and configures the cleanup watcher - it has no parameters of
		3130	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3131	pointless, I assure you.
		3132
		3133	=back
		3134
		3135	Example: Register an atexit handler to destroy the default loop, so any
		3136	cleanup functions are called.
		3137
		3138	static void
		3139	program_exits (void)
		3140	{
		3141	ev_loop_destroy (EV_DEFAULT_UC);
		3142	}
		3143
		3144	...
		3145	atexit (program_exits);
		3146
		3147
3009	=head2 C<ev_async> - how to wake up another event loop	3148	=head2 C<ev_async> - how to wake up an event loop
3010		3149
3011	In general, you cannot use an C<ev_loop> from multiple threads or other	3150	In general, you cannot use an C<ev_run> from multiple threads or other
3012	asynchronous sources such as signal handlers (as opposed to multiple event	3151	asynchronous sources such as signal handlers (as opposed to multiple event
3013	loops - those are of course safe to use in different threads).	3152	loops - those are of course safe to use in different threads).
3014		3153
3015	Sometimes, however, you need to wake up another event loop you do not	3154	Sometimes, however, you need to wake up an event loop you do not control,
3016	control, for example because it belongs to another thread. This is what	3155	for example because it belongs to another thread. This is what C<ev_async>
3017	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3156	watchers do: as long as the C<ev_async> watcher is active, you can signal
3018	can signal it by calling C<ev_async_send>, which is thread- and signal	3157	it by calling C<ev_async_send>, which is thread- and signal safe.
3019	safe.
3020		3158
3021	This functionality is very similar to C<ev_signal> watchers, as signals,	3159	This functionality is very similar to C<ev_signal> watchers, as signals,
3022	too, are asynchronous in nature, and signals, too, will be compressed	3160	too, are asynchronous in nature, and signals, too, will be compressed
3023	(i.e. the number of callback invocations may be less than the number of	3161	(i.e. the number of callback invocations may be less than the number of
3024	C<ev_async_sent> calls).	3162	C<ev_async_sent> calls).
…		…
3179		3317
3180	If C<timeout> is less than 0, then no timeout watcher will be	3318	If C<timeout> is less than 0, then no timeout watcher will be
3181	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3319	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
3182	repeat = 0) will be started. C<0> is a valid timeout.	3320	repeat = 0) will be started. C<0> is a valid timeout.
3183		3321
3184	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	3322	The callback has the type C<void (*cb)(int revents, void *arg)> and is
3185	passed an C<revents> set like normal event callbacks (a combination of	3323	passed an C<revents> set like normal event callbacks (a combination of
3186	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3324	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
3187	value passed to C<ev_once>. Note that it is possible to receive I<both>	3325	value passed to C<ev_once>. Note that it is possible to receive I<both>
3188	a timeout and an io event at the same time - you probably should give io	3326	a timeout and an io event at the same time - you probably should give io
3189	events precedence.	3327	events precedence.
3190		3328
3191	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3329	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
3192		3330
3193	static void stdin_ready (int revents, void *arg)	3331	static void stdin_ready (int revents, void *arg)
3194	{	3332	{
3195	if (revents & EV_READ)	3333	if (revents & EV_READ)
3196	/* stdin might have data for us, joy! */;	3334	/* stdin might have data for us, joy! */;
3197	else if (revents & EV_TIMEOUT)	3335	else if (revents & EV_TIMER)
3198	/* doh, nothing entered */;	3336	/* doh, nothing entered */;
3199	}	3337	}
3200		3338
3201	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3339	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3202		3340
…		…
3336	myclass obj;	3474	myclass obj;
3337	ev::io iow;	3475	ev::io iow;
3338	iow.set <myclass, &myclass::io_cb> (&obj);	3476	iow.set <myclass, &myclass::io_cb> (&obj);
3339		3477
3340	=item w->set (object *)	3478	=item w->set (object *)
3341
3342	This is an B<experimental> feature that might go away in a future version.
3343		3479
3344	This is a variation of a method callback - leaving out the method to call	3480	This is a variation of a method callback - leaving out the method to call
3345	will default the method to C<operator ()>, which makes it possible to use	3481	will default the method to C<operator ()>, which makes it possible to use
3346	functor objects without having to manually specify the C<operator ()> all	3482	functor objects without having to manually specify the C<operator ()> all
3347	the time. Incidentally, you can then also leave out the template argument	3483	the time. Incidentally, you can then also leave out the template argument
…		…
3387	Associates a different C<struct ev_loop> with this watcher. You can only	3523	Associates a different C<struct ev_loop> with this watcher. You can only
3388	do this when the watcher is inactive (and not pending either).	3524	do this when the watcher is inactive (and not pending either).
3389		3525
3390	=item w->set ([arguments])	3526	=item w->set ([arguments])
3391		3527
3392	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3528	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3393	called at least once. Unlike the C counterpart, an active watcher gets	3529	method or a suitable start method must be called at least once. Unlike the
3394	automatically stopped and restarted when reconfiguring it with this	3530	C counterpart, an active watcher gets automatically stopped and restarted
3395	method.	3531	when reconfiguring it with this method.
3396		3532
3397	=item w->start ()	3533	=item w->start ()
3398		3534
3399	Starts the watcher. Note that there is no C<loop> argument, as the	3535	Starts the watcher. Note that there is no C<loop> argument, as the
3400	constructor already stores the event loop.	3536	constructor already stores the event loop.
3401		3537
		3538	=item w->start ([arguments])
		3539
		3540	Instead of calling C<set> and C<start> methods separately, it is often
		3541	convenient to wrap them in one call. Uses the same type of arguments as
		3542	the configure C<set> method of the watcher.
		3543
3402	=item w->stop ()	3544	=item w->stop ()
3403		3545
3404	Stops the watcher if it is active. Again, no C<loop> argument.	3546	Stops the watcher if it is active. Again, no C<loop> argument.
3405		3547
3406	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3548	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3418		3560
3419	=back	3561	=back
3420		3562
3421	=back	3563	=back
3422		3564
3423	Example: Define a class with an IO and idle watcher, start one of them in	3565	Example: Define a class with two I/O and idle watchers, start the I/O
3424	the constructor.	3566	watchers in the constructor.
3425		3567
3426	class myclass	3568	class myclass
3427	{	3569	{
3428	ev::io io ; void io_cb (ev::io &w, int revents);	3570	ev::io io ; void io_cb (ev::io &w, int revents);
		3571	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3429	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3572	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3430		3573
3431	myclass (int fd)	3574	myclass (int fd)
3432	{	3575	{
3433	io .set <myclass, &myclass::io_cb > (this);	3576	io .set <myclass, &myclass::io_cb > (this);
		3577	io2 .set <myclass, &myclass::io2_cb > (this);
3434	idle.set <myclass, &myclass::idle_cb> (this);	3578	idle.set <myclass, &myclass::idle_cb> (this);
3435		3579
3436	io.start (fd, ev::READ);	3580	io.set (fd, ev::WRITE); // configure the watcher
		3581	io.start (); // start it whenever convenient
		3582
		3583	io2.start (fd, ev::READ); // set + start in one call
3437	}	3584	}
3438	};	3585	};
3439		3586
3440		3587
3441	=head1 OTHER LANGUAGE BINDINGS	3588	=head1 OTHER LANGUAGE BINDINGS
…		…
3515	loop argument"). The C<EV_A> form is used when this is the sole argument,	3662	loop argument"). The C<EV_A> form is used when this is the sole argument,
3516	C<EV_A_> is used when other arguments are following. Example:	3663	C<EV_A_> is used when other arguments are following. Example:
3517		3664
3518	ev_unref (EV_A);	3665	ev_unref (EV_A);
3519	ev_timer_add (EV_A_ watcher);	3666	ev_timer_add (EV_A_ watcher);
3520	ev_loop (EV_A_ 0);	3667	ev_run (EV_A_ 0);
3521		3668
3522	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3669	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3523	which is often provided by the following macro.	3670	which is often provided by the following macro.
3524		3671
3525	=item C<EV_P>, C<EV_P_>	3672	=item C<EV_P>, C<EV_P_>
…		…
3565	}	3712	}
3566		3713
3567	ev_check check;	3714	ev_check check;
3568	ev_check_init (&check, check_cb);	3715	ev_check_init (&check, check_cb);
3569	ev_check_start (EV_DEFAULT_ &check);	3716	ev_check_start (EV_DEFAULT_ &check);
3570	ev_loop (EV_DEFAULT_ 0);	3717	ev_run (EV_DEFAULT_ 0);
3571		3718
3572	=head1 EMBEDDING	3719	=head1 EMBEDDING
3573		3720
3574	Libev can (and often is) directly embedded into host	3721	Libev can (and often is) directly embedded into host
3575	applications. Examples of applications that embed it include the Deliantra	3722	applications. Examples of applications that embed it include the Deliantra
…		…
3660	define before including (or compiling) any of its files. The default in	3807	define before including (or compiling) any of its files. The default in
3661	the absence of autoconf is documented for every option.	3808	the absence of autoconf is documented for every option.
3662		3809
3663	Symbols marked with "(h)" do not change the ABI, and can have different	3810	Symbols marked with "(h)" do not change the ABI, and can have different
3664	values when compiling libev vs. including F<ev.h>, so it is permissible	3811	values when compiling libev vs. including F<ev.h>, so it is permissible
3665	to redefine them before including F<ev.h> without breakign compatibility	3812	to redefine them before including F<ev.h> without breaking compatibility
3666	to a compiled library. All other symbols change the ABI, which means all	3813	to a compiled library. All other symbols change the ABI, which means all
3667	users of libev and the libev code itself must be compiled with compatible	3814	users of libev and the libev code itself must be compiled with compatible
3668	settings.	3815	settings.
3669		3816
3670	=over 4	3817	=over 4
		3818
		3819	=item EV_COMPAT3 (h)
		3820
		3821	Backwards compatibility is a major concern for libev. This is why this
		3822	release of libev comes with wrappers for the functions and symbols that
		3823	have been renamed between libev version 3 and 4.
		3824
		3825	You can disable these wrappers (to test compatibility with future
		3826	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3827	sources. This has the additional advantage that you can drop the C<struct>
		3828	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3829	typedef in that case.
		3830
		3831	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3832	and in some even more future version the compatibility code will be
		3833	removed completely.
3671		3834
3672	=item EV_STANDALONE (h)	3835	=item EV_STANDALONE (h)
3673		3836
3674	Must always be C<1> if you do not use autoconf configuration, which	3837	Must always be C<1> if you do not use autoconf configuration, which
3675	keeps libev from including F<config.h>, and it also defines dummy	3838	keeps libev from including F<config.h>, and it also defines dummy
…		…
3882	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,	4045	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
3883	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.	4046	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3884		4047
3885	If undefined or defined to be C<1> (and the platform supports it), then	4048	If undefined or defined to be C<1> (and the platform supports it), then
3886	the respective watcher type is supported. If defined to be C<0>, then it	4049	the respective watcher type is supported. If defined to be C<0>, then it
3887	is not. Disabling watcher types mainly saves codesize.	4050	is not. Disabling watcher types mainly saves code size.
3888		4051
3889	=item EV_FEATURES	4052	=item EV_FEATURES
3890		4053
3891	If you need to shave off some kilobytes of code at the expense of some	4054	If you need to shave off some kilobytes of code at the expense of some
3892	speed (but with the full API), you can define this symbol to request	4055	speed (but with the full API), you can define this symbol to request
3893	certain subsets of functionality. The default is to enable all features	4056	certain subsets of functionality. The default is to enable all features
3894	that can be enabled on the platform.	4057	that can be enabled on the platform.
3895
3896	Note that using autoconf will usually override most of the features, so
3897	using this symbol makes sense mostly when embedding libev.
3898		4058
3899	A typical way to use this symbol is to define it to C<0> (or to a bitset	4059	A typical way to use this symbol is to define it to C<0> (or to a bitset
3900	with some broad features you want) and then selectively re-enable	4060	with some broad features you want) and then selectively re-enable
3901	additional parts you want, for example if you want everything minimal,	4061	additional parts you want, for example if you want everything minimal,
3902	but multiple event loop support, async and child watchers and the poll	4062	but multiple event loop support, async and child watchers and the poll
…		…
3915		4075
3916	=item C<1> - faster/larger code	4076	=item C<1> - faster/larger code
3917		4077
3918	Use larger code to speed up some operations.	4078	Use larger code to speed up some operations.
3919		4079
3920	Currently this is used to override some inlining decisions (enlarging the roughly	4080	Currently this is used to override some inlining decisions (enlarging the
3921	30% code size on amd64.	4081	code size by roughly 30% on amd64).
3922		4082
3923	When optimising for size, use of compiler flags such as C<-Os> with	4083	When optimising for size, use of compiler flags such as C<-Os> with
3924	gcc recommended, as well as C<-DNDEBUG>, as libev contains a number of	4084	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
3925	assertions.	4085	assertions.
3926		4086
3927	=item C<2> - faster/larger data structures	4087	=item C<2> - faster/larger data structures
3928		4088
3929	Replaces the small 2-heap for timer management by a faster 4-heap, larger	4089	Replaces the small 2-heap for timer management by a faster 4-heap, larger
3930	hash table sizes and so on. This will usually further increase codesize	4090	hash table sizes and so on. This will usually further increase code size
3931	and can additionally have an effect on the size of data structures at	4091	and can additionally have an effect on the size of data structures at
3932	runtime.	4092	runtime.
3933		4093
3934	=item C<4> - full API configuration	4094	=item C<4> - full API configuration
3935		4095
3936	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and	4096	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
3937	enables multiplicity (C<EV_MULTIPLICITY>=1).	4097	enables multiplicity (C<EV_MULTIPLICITY>=1).
3938		4098
		4099	=item C<8> - full API
		4100
3939	It also enables a lot of the "lesser used" core API functions. See C<ev.h>	4101	This enables a lot of the "lesser used" API functions. See C<ev.h> for
3940	for details on which parts of the API are still available without this	4102	details on which parts of the API are still available without this
3941	feature, and do not complain if this subset changes over time.	4103	feature, and do not complain if this subset changes over time.
3942		4104
3943	=item C<8> - enable all optional watcher types	4105	=item C<16> - enable all optional watcher types
3944		4106
3945	Enables all optional watcher types. If you want to selectively enable	4107	Enables all optional watcher types. If you want to selectively enable
3946	only some watcher types other than I/O and timers (e.g. prepare,	4108	only some watcher types other than I/O and timers (e.g. prepare,
3947	embed, async, child...) you can enable them manually by defining	4109	embed, async, child...) you can enable them manually by defining
3948	C<EV_watchertype_ENABLE> to C<1> instead.	4110	C<EV_watchertype_ENABLE> to C<1> instead.
3949		4111
3950	=item C<16> - enable all backends	4112	=item C<32> - enable all backends
3951		4113
3952	This enables all backends - without this feature, you need to enable at	4114	This enables all backends - without this feature, you need to enable at
3953	least one backend manually (C<EV_USE_SELECT> is a good choice).	4115	least one backend manually (C<EV_USE_SELECT> is a good choice).
3954		4116
3955	=item C<32> - enable OS-specific "helper" APIs	4117	=item C<64> - enable OS-specific "helper" APIs
3956		4118
3957	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by	4119	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
3958	default.	4120	default.
3959		4121
3960	=back	4122	=back
3961		4123
3962	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>	4124	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
3963	reduces the compiled size of libev from 24.7Kb to 6.5Kb on my GNU/Linux	4125	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
3964	amd64 system, while still giving you I/O watchers, timers and monotonic	4126	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
3965	clock support.	4127	watchers, timers and monotonic clock support.
3966		4128
3967	With an intelligent-enough linker (gcc+binutils are intelligent enough	4129	With an intelligent-enough linker (gcc+binutils are intelligent enough
3968	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by	4130	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
3969	your program might be left out as well - a binary starting a timer and an	4131	your program might be left out as well - a binary starting a timer and an
3970	I/O watcher then might come out at only 5Kb.	4132	I/O watcher then might come out at only 5Kb.
3971		4133
3972	=item EV_AVOID_STDIO	4134	=item EV_AVOID_STDIO
3973		4135
3974	If this is set to C<1> at compiletime, then libev will avoid using stdio	4136	If this is set to C<1> at compiletime, then libev will avoid using stdio
3975	functions (printf, scanf, perror etc.). This will increase the codesize	4137	functions (printf, scanf, perror etc.). This will increase the code size
3976	somewhat, but if your program doesn't otherwise depend on stdio and your	4138	somewhat, but if your program doesn't otherwise depend on stdio and your
3977	libc allows it, this avoids linking in the stdio library which is quite	4139	libc allows it, this avoids linking in the stdio library which is quite
3978	big.	4140	big.
3979		4141
3980	Note that error messages might become less precise when this option is	4142	Note that error messages might become less precise when this option is
…		…
3984		4146
3985	The highest supported signal number, +1 (or, the number of	4147	The highest supported signal number, +1 (or, the number of
3986	signals): Normally, libev tries to deduce the maximum number of signals	4148	signals): Normally, libev tries to deduce the maximum number of signals
3987	automatically, but sometimes this fails, in which case it can be	4149	automatically, but sometimes this fails, in which case it can be
3988	specified. Also, using a lower number than detected (C<32> should be	4150	specified. Also, using a lower number than detected (C<32> should be
3989	good for about any system in existance) can save some memory, as libev	4151	good for about any system in existence) can save some memory, as libev
3990	statically allocates some 12-24 bytes per signal number.	4152	statically allocates some 12-24 bytes per signal number.
3991		4153
3992	=item EV_PID_HASHSIZE	4154	=item EV_PID_HASHSIZE
3993		4155
3994	C<ev_child> watchers use a small hash table to distribute workload by	4156	C<ev_child> watchers use a small hash table to distribute workload by
…		…
4026	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4188	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4027	will be C<0>.	4189	will be C<0>.
4028		4190
4029	=item EV_VERIFY	4191	=item EV_VERIFY
4030		4192
4031	Controls how much internal verification (see C<ev_loop_verify ()>) will	4193	Controls how much internal verification (see C<ev_verify ()>) will
4032	be done: If set to C<0>, no internal verification code will be compiled	4194	be done: If set to C<0>, no internal verification code will be compiled
4033	in. If set to C<1>, then verification code will be compiled in, but not	4195	in. If set to C<1>, then verification code will be compiled in, but not
4034	called. If set to C<2>, then the internal verification code will be	4196	called. If set to C<2>, then the internal verification code will be
4035	called once per loop, which can slow down libev. If set to C<3>, then the	4197	called once per loop, which can slow down libev. If set to C<3>, then the
4036	verification code will be called very frequently, which will slow down	4198	verification code will be called very frequently, which will slow down
…		…
4040	will be C<0>.	4202	will be C<0>.
4041		4203
4042	=item EV_COMMON	4204	=item EV_COMMON
4043		4205
4044	By default, all watchers have a C<void *data> member. By redefining	4206	By default, all watchers have a C<void *data> member. By redefining
4045	this macro to a something else you can include more and other types of	4207	this macro to something else you can include more and other types of
4046	members. You have to define it each time you include one of the files,	4208	members. You have to define it each time you include one of the files,
4047	though, and it must be identical each time.	4209	though, and it must be identical each time.
4048		4210
4049	For example, the perl EV module uses something like this:	4211	For example, the perl EV module uses something like this:
4050		4212
…		…
4103	file.	4265	file.
4104		4266
4105	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4267	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
4106	that everybody includes and which overrides some configure choices:	4268	that everybody includes and which overrides some configure choices:
4107		4269
4108	#define EV_FEATURES 0	4270	#define EV_FEATURES 8
4109	#define EV_USE_SELECT 1	4271	#define EV_USE_SELECT 1
		4272	#define EV_PREPARE_ENABLE 1
		4273	#define EV_IDLE_ENABLE 1
		4274	#define EV_SIGNAL_ENABLE 1
		4275	#define EV_CHILD_ENABLE 1
		4276	#define EV_USE_STDEXCEPT 0
4110	#define EV_CONFIG_H <config.h>	4277	#define EV_CONFIG_H <config.h>
4111		4278
4112	#include "ev++.h"	4279	#include "ev++.h"
4113		4280
4114	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4281	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
…		…
4246	userdata *u = ev_userdata (EV_A);	4413	userdata *u = ev_userdata (EV_A);
4247	pthread_mutex_lock (&u->lock);	4414	pthread_mutex_lock (&u->lock);
4248	}	4415	}
4249		4416
4250	The event loop thread first acquires the mutex, and then jumps straight	4417	The event loop thread first acquires the mutex, and then jumps straight
4251	into C<ev_loop>:	4418	into C<ev_run>:
4252		4419
4253	void *	4420	void *
4254	l_run (void *thr_arg)	4421	l_run (void *thr_arg)
4255	{	4422	{
4256	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4423	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4257		4424
4258	l_acquire (EV_A);	4425	l_acquire (EV_A);
4259	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4426	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4260	ev_loop (EV_A_ 0);	4427	ev_run (EV_A_ 0);
4261	l_release (EV_A);	4428	l_release (EV_A);
4262		4429
4263	return 0;	4430	return 0;
4264	}	4431	}
4265		4432
…		…
4317		4484
4318	=head3 COROUTINES	4485	=head3 COROUTINES
4319		4486
4320	Libev is very accommodating to coroutines ("cooperative threads"):	4487	Libev is very accommodating to coroutines ("cooperative threads"):
4321	libev fully supports nesting calls to its functions from different	4488	libev fully supports nesting calls to its functions from different
4322	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4489	coroutines (e.g. you can call C<ev_run> on the same loop from two
4323	different coroutines, and switch freely between both coroutines running	4490	different coroutines, and switch freely between both coroutines running
4324	the loop, as long as you don't confuse yourself). The only exception is	4491	the loop, as long as you don't confuse yourself). The only exception is
4325	that you must not do this from C<ev_periodic> reschedule callbacks.	4492	that you must not do this from C<ev_periodic> reschedule callbacks.
4326		4493
4327	Care has been taken to ensure that libev does not keep local state inside	4494	Care has been taken to ensure that libev does not keep local state inside
4328	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4495	C<ev_run>, and other calls do not usually allow for coroutine switches as
4329	they do not call any callbacks.	4496	they do not call any callbacks.
4330		4497
4331	=head2 COMPILER WARNINGS	4498	=head2 COMPILER WARNINGS
4332		4499
4333	Depending on your compiler and compiler settings, you might get no or a	4500	Depending on your compiler and compiler settings, you might get no or a
…		…
4344	maintainable.	4511	maintainable.
4345		4512
4346	And of course, some compiler warnings are just plain stupid, or simply	4513	And of course, some compiler warnings are just plain stupid, or simply
4347	wrong (because they don't actually warn about the condition their message	4514	wrong (because they don't actually warn about the condition their message
4348	seems to warn about). For example, certain older gcc versions had some	4515	seems to warn about). For example, certain older gcc versions had some
4349	warnings that resulted an extreme number of false positives. These have	4516	warnings that resulted in an extreme number of false positives. These have
4350	been fixed, but some people still insist on making code warn-free with	4517	been fixed, but some people still insist on making code warn-free with
4351	such buggy versions.	4518	such buggy versions.
4352		4519
4353	While libev is written to generate as few warnings as possible,	4520	While libev is written to generate as few warnings as possible,
4354	"warn-free" code is not a goal, and it is recommended not to build libev	4521	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4390	I suggest using suppression lists.	4557	I suggest using suppression lists.
4391		4558
4392		4559
4393	=head1 PORTABILITY NOTES	4560	=head1 PORTABILITY NOTES
4394		4561
		4562	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4563
		4564	GNU/Linux is the only common platform that supports 64 bit file/large file
		4565	interfaces but I<disables> them by default.
		4566
		4567	That means that libev compiled in the default environment doesn't support
		4568	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4569
		4570	Unfortunately, many programs try to work around this GNU/Linux issue
		4571	by enabling the large file API, which makes them incompatible with the
		4572	standard libev compiled for their system.
		4573
		4574	Likewise, libev cannot enable the large file API itself as this would
		4575	suddenly make it incompatible to the default compile time environment,
		4576	i.e. all programs not using special compile switches.
		4577
		4578	=head2 OS/X AND DARWIN BUGS
		4579
		4580	The whole thing is a bug if you ask me - basically any system interface
		4581	you touch is broken, whether it is locales, poll, kqueue or even the
		4582	OpenGL drivers.
		4583
		4584	=head3 C<kqueue> is buggy
		4585
		4586	The kqueue syscall is broken in all known versions - most versions support
		4587	only sockets, many support pipes.
		4588
		4589	Libev tries to work around this by not using C<kqueue> by default on this
		4590	rotten platform, but of course you can still ask for it when creating a
		4591	loop - embedding a socket-only kqueue loop into a select-based one is
		4592	probably going to work well.
		4593
		4594	=head3 C<poll> is buggy
		4595
		4596	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4597	implementation by something calling C<kqueue> internally around the 10.5.6
		4598	release, so now C<kqueue> I<and> C<poll> are broken.
		4599
		4600	Libev tries to work around this by not using C<poll> by default on
		4601	this rotten platform, but of course you can still ask for it when creating
		4602	a loop.
		4603
		4604	=head3 C<select> is buggy
		4605
		4606	All that's left is C<select>, and of course Apple found a way to fuck this
		4607	one up as well: On OS/X, C<select> actively limits the number of file
		4608	descriptors you can pass in to 1024 - your program suddenly crashes when
		4609	you use more.
		4610
		4611	There is an undocumented "workaround" for this - defining
		4612	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4613	work on OS/X.
		4614
		4615	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4616
		4617	=head3 C<errno> reentrancy
		4618
		4619	The default compile environment on Solaris is unfortunately so
		4620	thread-unsafe that you can't even use components/libraries compiled
		4621	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4622	defined by default. A valid, if stupid, implementation choice.
		4623
		4624	If you want to use libev in threaded environments you have to make sure
		4625	it's compiled with C<_REENTRANT> defined.
		4626
		4627	=head3 Event port backend
		4628
		4629	The scalable event interface for Solaris is called "event
		4630	ports". Unfortunately, this mechanism is very buggy in all major
		4631	releases. If you run into high CPU usage, your program freezes or you get
		4632	a large number of spurious wakeups, make sure you have all the relevant
		4633	and latest kernel patches applied. No, I don't know which ones, but there
		4634	are multiple ones to apply, and afterwards, event ports actually work
		4635	great.
		4636
		4637	If you can't get it to work, you can try running the program by setting
		4638	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4639	C<select> backends.
		4640
		4641	=head2 AIX POLL BUG
		4642
		4643	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4644	this by trying to avoid the poll backend altogether (i.e. it's not even
		4645	compiled in), which normally isn't a big problem as C<select> works fine
		4646	with large bitsets on AIX, and AIX is dead anyway.
		4647
4395	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4648	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4649
		4650	=head3 General issues
4396		4651
4397	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4652	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4398	requires, and its I/O model is fundamentally incompatible with the POSIX	4653	requires, and its I/O model is fundamentally incompatible with the POSIX
4399	model. Libev still offers limited functionality on this platform in	4654	model. Libev still offers limited functionality on this platform in
4400	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4655	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4401	descriptors. This only applies when using Win32 natively, not when using	4656	descriptors. This only applies when using Win32 natively, not when using
4402	e.g. cygwin.	4657	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4658	as every compielr comes with a slightly differently broken/incompatible
		4659	environment.
4403		4660
4404	Lifting these limitations would basically require the full	4661	Lifting these limitations would basically require the full
4405	re-implementation of the I/O system. If you are into these kinds of	4662	re-implementation of the I/O system. If you are into this kind of thing,
4406	things, then note that glib does exactly that for you in a very portable	4663	then note that glib does exactly that for you in a very portable way (note
4407	way (note also that glib is the slowest event library known to man).	4664	also that glib is the slowest event library known to man).
4408		4665
4409	There is no supported compilation method available on windows except	4666	There is no supported compilation method available on windows except
4410	embedding it into other applications.	4667	embedding it into other applications.
4411		4668
4412	Sensible signal handling is officially unsupported by Microsoft - libev	4669	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4440	you do I<not> compile the F<ev.c> or any other embedded source files!):	4697	you do I<not> compile the F<ev.c> or any other embedded source files!):
4441		4698
4442	#include "evwrap.h"	4699	#include "evwrap.h"
4443	#include "ev.c"	4700	#include "ev.c"
4444		4701
4445	=over 4
4446
4447	=item The winsocket select function	4702	=head3 The winsocket C<select> function
4448		4703
4449	The winsocket C<select> function doesn't follow POSIX in that it	4704	The winsocket C<select> function doesn't follow POSIX in that it
4450	requires socket I<handles> and not socket I<file descriptors> (it is	4705	requires socket I<handles> and not socket I<file descriptors> (it is
4451	also extremely buggy). This makes select very inefficient, and also	4706	also extremely buggy). This makes select very inefficient, and also
4452	requires a mapping from file descriptors to socket handles (the Microsoft	4707	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4461	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4716	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4462		4717
4463	Note that winsockets handling of fd sets is O(n), so you can easily get a	4718	Note that winsockets handling of fd sets is O(n), so you can easily get a
4464	complexity in the O(n²) range when using win32.	4719	complexity in the O(n²) range when using win32.
4465		4720
4466	=item Limited number of file descriptors	4721	=head3 Limited number of file descriptors
4467		4722
4468	Windows has numerous arbitrary (and low) limits on things.	4723	Windows has numerous arbitrary (and low) limits on things.
4469		4724
4470	Early versions of winsocket's select only supported waiting for a maximum	4725	Early versions of winsocket's select only supported waiting for a maximum
4471	of C<64> handles (probably owning to the fact that all windows kernels	4726	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4486	runtime libraries. This might get you to about C<512> or C<2048> sockets	4741	runtime libraries. This might get you to about C<512> or C<2048> sockets
4487	(depending on windows version and/or the phase of the moon). To get more,	4742	(depending on windows version and/or the phase of the moon). To get more,
4488	you need to wrap all I/O functions and provide your own fd management, but	4743	you need to wrap all I/O functions and provide your own fd management, but
4489	the cost of calling select (O(n²)) will likely make this unworkable.	4744	the cost of calling select (O(n²)) will likely make this unworkable.
4490		4745
4491	=back
4492
4493	=head2 PORTABILITY REQUIREMENTS	4746	=head2 PORTABILITY REQUIREMENTS
4494		4747
4495	In addition to a working ISO-C implementation and of course the	4748	In addition to a working ISO-C implementation and of course the
4496	backend-specific APIs, libev relies on a few additional extensions:	4749	backend-specific APIs, libev relies on a few additional extensions:
4497		4750
…		…
4503	Libev assumes not only that all watcher pointers have the same internal	4756	Libev assumes not only that all watcher pointers have the same internal
4504	structure (guaranteed by POSIX but not by ISO C for example), but it also	4757	structure (guaranteed by POSIX but not by ISO C for example), but it also
4505	assumes that the same (machine) code can be used to call any watcher	4758	assumes that the same (machine) code can be used to call any watcher
4506	callback: The watcher callbacks have different type signatures, but libev	4759	callback: The watcher callbacks have different type signatures, but libev
4507	calls them using an C<ev_watcher *> internally.	4760	calls them using an C<ev_watcher *> internally.
		4761
		4762	=item pointer accesses must be thread-atomic
		4763
		4764	Accessing a pointer value must be atomic, it must both be readable and
		4765	writable in one piece - this is the case on all current architectures.
4508		4766
4509	=item C<sig_atomic_t volatile> must be thread-atomic as well	4767	=item C<sig_atomic_t volatile> must be thread-atomic as well
4510		4768
4511	The type C<sig_atomic_t volatile> (or whatever is defined as	4769	The type C<sig_atomic_t volatile> (or whatever is defined as
4512	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different	4770	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
…		…
4535	watchers.	4793	watchers.
4536		4794
4537	=item C<double> must hold a time value in seconds with enough accuracy	4795	=item C<double> must hold a time value in seconds with enough accuracy
4538		4796
4539	The type C<double> is used to represent timestamps. It is required to	4797	The type C<double> is used to represent timestamps. It is required to
4540	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4798	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4541	enough for at least into the year 4000. This requirement is fulfilled by	4799	good enough for at least into the year 4000 with millisecond accuracy
		4800	(the design goal for libev). This requirement is overfulfilled by
4542	implementations implementing IEEE 754, which is basically all existing	4801	implementations using IEEE 754, which is basically all existing ones. With
4543	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4802	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4544	2200.
4545		4803
4546	=back	4804	=back
4547		4805
4548	If you know of other additional requirements drop me a note.	4806	If you know of other additional requirements drop me a note.
4549		4807
…		…
4617	involves iterating over all running async watchers or all signal numbers.	4875	involves iterating over all running async watchers or all signal numbers.
4618		4876
4619	=back	4877	=back
4620		4878
4621		4879
		4880	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4881
		4882	The major version 4 introduced some incompatible changes to the API.
		4883
		4884	At the moment, the C<ev.h> header file provides compatibility definitions
		4885	for all changes, so most programs should still compile. The compatibility
		4886	layer might be removed in later versions of libev, so better update to the
		4887	new API early than late.
		4888
		4889	=over 4
		4890
		4891	=item C<EV_COMPAT3> backwards compatibility mechanism
		4892
		4893	The backward compatibility mechanism can be controlled by
		4894	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4895	section.
		4896
		4897	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4898
		4899	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4900
		4901	ev_loop_destroy (EV_DEFAULT_UC);
		4902	ev_loop_fork (EV_DEFAULT);
		4903
		4904	=item function/symbol renames
		4905
		4906	A number of functions and symbols have been renamed:
		4907
		4908	ev_loop => ev_run
		4909	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4910	EVLOOP_ONESHOT => EVRUN_ONCE
		4911
		4912	ev_unloop => ev_break
		4913	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4914	EVUNLOOP_ONE => EVBREAK_ONE
		4915	EVUNLOOP_ALL => EVBREAK_ALL
		4916
		4917	EV_TIMEOUT => EV_TIMER
		4918
		4919	ev_loop_count => ev_iteration
		4920	ev_loop_depth => ev_depth
		4921	ev_loop_verify => ev_verify
		4922
		4923	Most functions working on C<struct ev_loop> objects don't have an
		4924	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4925	associated constants have been renamed to not collide with the C<struct
		4926	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4927	as all other watcher types. Note that C<ev_loop_fork> is still called
		4928	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4929	typedef.
		4930
		4931	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4932
		4933	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4934	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4935	and work, but the library code will of course be larger.
		4936
		4937	=back
		4938
		4939
4622	=head1 GLOSSARY	4940	=head1 GLOSSARY
4623		4941
4624	=over 4	4942	=over 4
4625		4943
4626	=item active	4944	=item active
4627		4945
4628	A watcher is active as long as it has been started (has been attached to	4946	A watcher is active as long as it has been started and not yet stopped.
4629	an event loop) but not yet stopped (disassociated from the event loop).	4947	See L<WATCHER STATES> for details.
4630		4948
4631	=item application	4949	=item application
4632		4950
4633	In this document, an application is whatever is using libev.	4951	In this document, an application is whatever is using libev.
		4952
		4953	=item backend
		4954
		4955	The part of the code dealing with the operating system interfaces.
4634		4956
4635	=item callback	4957	=item callback
4636		4958
4637	The address of a function that is called when some event has been	4959	The address of a function that is called when some event has been
4638	detected. Callbacks are being passed the event loop, the watcher that	4960	detected. Callbacks are being passed the event loop, the watcher that
4639	received the event, and the actual event bitset.	4961	received the event, and the actual event bitset.
4640		4962
4641	=item callback invocation	4963	=item callback/watcher invocation
4642		4964
4643	The act of calling the callback associated with a watcher.	4965	The act of calling the callback associated with a watcher.
4644		4966
4645	=item event	4967	=item event
4646		4968
4647	A change of state of some external event, such as data now being available	4969	A change of state of some external event, such as data now being available
4648	for reading on a file descriptor, time having passed or simply not having	4970	for reading on a file descriptor, time having passed or simply not having
4649	any other events happening anymore.	4971	any other events happening anymore.
4650		4972
4651	In libev, events are represented as single bits (such as C<EV_READ> or	4973	In libev, events are represented as single bits (such as C<EV_READ> or
4652	C<EV_TIMEOUT>).	4974	C<EV_TIMER>).
4653		4975
4654	=item event library	4976	=item event library
4655		4977
4656	A software package implementing an event model and loop.	4978	A software package implementing an event model and loop.
4657		4979
…		…
4665	The model used to describe how an event loop handles and processes	4987	The model used to describe how an event loop handles and processes
4666	watchers and events.	4988	watchers and events.
4667		4989
4668	=item pending	4990	=item pending
4669		4991
4670	A watcher is pending as soon as the corresponding event has been detected,	4992	A watcher is pending as soon as the corresponding event has been
4671	and stops being pending as soon as the watcher will be invoked or its	4993	detected. See L<WATCHER STATES> for details.
4672	pending status is explicitly cleared by the application.
4673
4674	A watcher can be pending, but not active. Stopping a watcher also clears
4675	its pending status.
4676		4994
4677	=item real time	4995	=item real time
4678		4996
4679	The physical time that is observed. It is apparently strictly monotonic :)	4997	The physical time that is observed. It is apparently strictly monotonic :)
4680		4998
…		…
4687	=item watcher	5005	=item watcher
4688		5006
4689	A data structure that describes interest in certain events. Watchers need	5007	A data structure that describes interest in certain events. Watchers need
4690	to be started (attached to an event loop) before they can receive events.	5008	to be started (attached to an event loop) before they can receive events.
4691		5009
4692	=item watcher invocation
4693
4694	The act of calling the callback associated with a watcher.
4695
4696	=back	5010	=back
4697		5011
4698	=head1 AUTHOR	5012	=head1 AUTHOR
4699		5013
4700	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5014	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
		5015	Magnusson and Emanuele Giaquinta.
4701		5016

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