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Revision 1.282 by root, Wed Mar 10 08:19:39 2010 UTC vs.
Revision 1.322 by root, Sun Oct 24 17:58:41 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 signals and child events, and dynamically created event loops
302	not.	306	which do not.
303		307
304	=over 4	308	=over 4
305		309
306	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
307		311
308	This will initialise the default event loop if it hasn't been initialised	312	This returns the "default" event loop object, which is what you should
309	yet and return it. If the default loop could not be initialised, returns	313	normally use when you just need "the event loop". Event loop objects and
310	false. If it already was initialised it simply returns it (and ignores the	314	the C<flags> parameter are described in more detail in the entry for
311	flags. If that is troubling you, check C<ev_backend ()> afterwards).	315	C<ev_loop_new>.
		316
		317	If the default loop is already initialised then this function simply
		318	returns it (and ignores the flags. If that is troubling you, check
		319	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		320	flags, which should almost always be C<0>, unless the caller is also the
		321	one calling C<ev_run> or otherwise qualifies as "the main program".
312		322
313	If you don't know what event loop to use, use the one returned from this	323	If you don't know what event loop to use, use the one returned from this
314	function.	324	function (or via the C<EV_DEFAULT> macro).
315		325
316	Note that this function is I<not> thread-safe, so if you want to use it	326	Note that this function is I<not> thread-safe, so if you want to use it
317	from multiple threads, you have to lock (note also that this is unlikely,	327	from multiple threads, you have to employ some kind of mutex (note also
318	as loops cannot be shared easily between threads anyway).	328	that this case is unlikely, as loops cannot be shared easily between
		329	threads anyway).
319		330
320	The default loop is the only loop that can handle C<ev_signal> and	331	The default loop is the only loop that can handle C<ev_child> watchers,
321	C<ev_child> watchers, and to do this, it always registers a handler	332	and to do this, it always registers a handler for C<SIGCHLD>. If this is
322	for C<SIGCHLD>. If this is a problem for your application you can either	333	a problem for your application you can either create a dynamic loop with
323	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	334	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
324	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	335	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
325	C<ev_default_init>.	336
		337	Example: This is the most typical usage.
		338
		339	if (!ev_default_loop (0))
		340	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		341
		342	Example: Restrict libev to the select and poll backends, and do not allow
		343	environment settings to be taken into account:
		344
		345	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
		346
		347	Example: Use whatever libev has to offer, but make sure that kqueue is
		348	used if available (warning, breaks stuff, best use only with your own
		349	private event loop and only if you know the OS supports your types of
		350	fds):
		351
		352	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
		353
		354	=item struct ev_loop *ev_loop_new (unsigned int flags)
		355
		356	This will create and initialise a new event loop object. If the loop
		357	could not be initialised, returns false.
		358
		359	Note that this function I<is> thread-safe, and one common way to use
		360	libev with threads is indeed to create one loop per thread, and using the
		361	default loop in the "main" or "initial" thread.
326		362
327	The flags argument can be used to specify special behaviour or specific	363	The flags argument can be used to specify special behaviour or specific
328	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	364	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
329		365
330	The following flags are supported:	366	The following flags are supported:
…		…
345	useful to try out specific backends to test their performance, or to work	381	useful to try out specific backends to test their performance, or to work
346	around bugs.	382	around bugs.
347		383
348	=item C<EVFLAG_FORKCHECK>	384	=item C<EVFLAG_FORKCHECK>
349		385
350	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after	386	Instead of calling C<ev_loop_fork> manually after a fork, you can also
351	a fork, you can also make libev check for a fork in each iteration by	387	make libev check for a fork in each iteration by enabling this flag.
352	enabling this flag.
353		388
354	This works by calling C<getpid ()> on every iteration of the loop,	389	This works by calling C<getpid ()> on every iteration of the loop,
355	and thus this might slow down your event loop if you do a lot of loop	390	and thus this might slow down your event loop if you do a lot of loop
356	iterations and little real work, but is usually not noticeable (on my	391	iterations and little real work, but is usually not noticeable (on my
357	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	392	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
…		…
439	of course I<doesn't>, and epoll just loves to report events for totally	474	of course I<doesn't>, and epoll just loves to report events for totally
440	I<different> file descriptors (even already closed ones, so one cannot	475	I<different> file descriptors (even already closed ones, so one cannot
441	even remove them from the set) than registered in the set (especially	476	even remove them from the set) than registered in the set (especially
442	on SMP systems). Libev tries to counter these spurious notifications by	477	on SMP systems). Libev tries to counter these spurious notifications by
443	employing an additional generation counter and comparing that against the	478	employing an additional generation counter and comparing that against the
444	events to filter out spurious ones, recreating the set when required.	479	events to filter out spurious ones, recreating the set when required. Last
		480	not least, it also refuses to work with some file descriptors which work
		481	perfectly fine with C<select> (files, many character devices...).
445		482
446	While stopping, setting and starting an I/O watcher in the same iteration	483	While stopping, setting and starting an I/O watcher in the same iteration
447	will result in some caching, there is still a system call per such	484	will result in some caching, there is still a system call per such
448	incident (because the same I<file descriptor> could point to a different	485	incident (because the same I<file descriptor> could point to a different
449	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	486	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
547	If one or more of the backend flags are or'ed into the flags value,	584	If one or more of the backend flags are or'ed into the flags value,
548	then only these backends will be tried (in the reverse order as listed	585	then only these backends will be tried (in the reverse order as listed
549	here). If none are specified, all backends in C<ev_recommended_backends	586	here). If none are specified, all backends in C<ev_recommended_backends
550	()> will be tried.	587	()> will be tried.
551		588
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.	589	Example: Try to create a event loop that uses epoll and nothing else.
581		590
582	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	591	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
583	if (!epoller)	592	if (!epoller)
584	fatal ("no epoll found here, maybe it hides under your chair");	593	fatal ("no epoll found here, maybe it hides under your chair");
585		594
586	=item ev_default_destroy ()	595	=item ev_loop_destroy (loop)
587		596
588	Destroys the default loop again (frees all memory and kernel state	597	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	598	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	599	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>	600	responsibility to either stop all watchers cleanly yourself I<before>
592	calling this function, or cope with the fact afterwards (which is usually	601	calling this function, or cope with the fact afterwards (which is usually
593	the easiest thing, you can just ignore the watchers and/or C<free ()> them	602	the easiest thing, you can just ignore the watchers and/or C<free ()> them
…		…
595		604
596	Note that certain global state, such as signal state (and installed signal	605	Note that certain global state, such as signal state (and installed signal
597	handlers), will not be freed by this function, and related watchers (such	606	handlers), will not be freed by this function, and related watchers (such
598	as signal and child watchers) would need to be stopped manually.	607	as signal and child watchers) would need to be stopped manually.
599		608
600	In general it is not advisable to call this function except in the	609	This function is normally used on loop objects allocated by
601	rare occasion where you really need to free e.g. the signal handling	610	C<ev_loop_new>, but it can also be used on the default loop returned by
		611	C<ev_default_loop>, in which case it is not thread-safe.
		612
		613	Note that it is not advisable to call this function on the default loop
		614	except in the rare occasion where you really need to free it's resources.
602	pipe fds. If you need dynamically allocated loops it is better to use	615	If you need dynamically allocated loops it is better to use C<ev_loop_new>
603	C<ev_loop_new> and C<ev_loop_destroy>.	616	and C<ev_loop_destroy>.
604		617
605	=item ev_loop_destroy (loop)	618	=item ev_loop_fork (loop)
606		619
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	620	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	621	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	622	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	623	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	624	child before resuming or calling C<ev_run>.
617	functions, and it will only take effect at the next C<ev_loop> iteration.	625
		626	Again, you I<have> to call it on I<any> loop that you want to re-use after
		627	a fork, I<even if you do not plan to use the loop in the parent>. This is
		628	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
		629	during fork.
618		630
619	On the other hand, you only need to call this function in the child	631	On the other hand, you only need to call this function in the child
620	process if and only if you want to use the event library in the child. If	632	process if and only if you want to use the event loop in the child. If
621	you just fork+exec, you don't have to call it at all.	633	you just fork+exec or create a new loop in the child, you don't have to
		634	call it at all (in fact, C<epoll> is so badly broken that it makes a
		635	difference, but libev will usually detect this case on its own and do a
		636	costly reset of the backend).
622		637
623	The function itself is quite fast and it's usually not a problem to call	638	The function itself is quite fast and it's usually not a problem to call
624	it just in case after a fork. To make this easy, the function will fit in	639	it just in case after a fork.
625	quite nicely into a call to C<pthread_atfork>:
626		640
		641	Example: Automate calling C<ev_loop_fork> on the default loop when
		642	using pthreads.
		643
		644	static void
		645	post_fork_child (void)
		646	{
		647	ev_loop_fork (EV_DEFAULT);
		648	}
		649
		650	...
627	pthread_atfork (0, 0, ev_default_fork);	651	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		652
636	=item int ev_is_default_loop (loop)	653	=item int ev_is_default_loop (loop)
637		654
638	Returns true when the given loop is, in fact, the default loop, and false	655	Returns true when the given loop is, in fact, the default loop, and false
639	otherwise.	656	otherwise.
640		657
641	=item unsigned int ev_loop_count (loop)	658	=item unsigned int ev_iteration (loop)
642		659
643	Returns the count of loop iterations for the loop, which is identical to	660	Returns the current iteration count for the event loop, which is identical
644	the number of times libev did poll for new events. It starts at C<0> and	661	to the number of times libev did poll for new events. It starts at C<0>
645	happily wraps around with enough iterations.	662	and happily wraps around with enough iterations.
646		663
647	This value can sometimes be useful as a generation counter of sorts (it	664	This value can sometimes be useful as a generation counter of sorts (it
648	"ticks" the number of loop iterations), as it roughly corresponds with	665	"ticks" the number of loop iterations), as it roughly corresponds with
649	C<ev_prepare> and C<ev_check> calls.	666	C<ev_prepare> and C<ev_check> calls - and is incremented between the
		667	prepare and check phases.
650		668
651	=item unsigned int ev_loop_depth (loop)	669	=item unsigned int ev_depth (loop)
652		670
653	Returns the number of times C<ev_loop> was entered minus the number of	671	Returns the number of times C<ev_run> was entered minus the number of
654	times C<ev_loop> was exited, in other words, the recursion depth.	672	times C<ev_run> was exited, in other words, the recursion depth.
655		673
656	Outside C<ev_loop>, this number is zero. In a callback, this number is	674	Outside C<ev_run>, this number is zero. In a callback, this number is
657	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	675	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
658	in which case it is higher.	676	in which case it is higher.
659		677
660	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	678	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
661	etc.), doesn't count as exit.	679	etc.), doesn't count as "exit" - consider this as a hint to avoid such
		680	ungentleman-like behaviour unless it's really convenient.
662		681
663	=item unsigned int ev_backend (loop)	682	=item unsigned int ev_backend (loop)
664		683
665	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	684	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
666	use.	685	use.
…		…
675		694
676	=item ev_now_update (loop)	695	=item ev_now_update (loop)
677		696
678	Establishes the current time by querying the kernel, updating the time	697	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	698	returned by C<ev_now ()> in the progress. This is a costly operation and
680	is usually done automatically within C<ev_loop ()>.	699	is usually done automatically within C<ev_run ()>.
681		700
682	This function is rarely useful, but when some event callback runs for a	701	This function is rarely useful, but when some event callback runs for a
683	very long time without entering the event loop, updating libev's idea of	702	very long time without entering the event loop, updating libev's idea of
684	the current time is a good idea.	703	the current time is a good idea.
685		704
…		…
687		706
688	=item ev_suspend (loop)	707	=item ev_suspend (loop)
689		708
690	=item ev_resume (loop)	709	=item ev_resume (loop)
691		710
692	These two functions suspend and resume a loop, for use when the loop is	711	These two functions suspend and resume an event loop, for use when the
693	not used for a while and timeouts should not be processed.	712	loop is not used for a while and timeouts should not be processed.
694		713
695	A typical use case would be an interactive program such as a game: When	714	A typical use case would be an interactive program such as a game: When
696	the user presses C<^Z> to suspend the game and resumes it an hour later it	715	the user presses C<^Z> to suspend the game and resumes it an hour later it
697	would be best to handle timeouts as if no time had actually passed while	716	would be best to handle timeouts as if no time had actually passed while
698	the program was suspended. This can be achieved by calling C<ev_suspend>	717	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
700	C<ev_resume> directly afterwards to resume timer processing.	719	C<ev_resume> directly afterwards to resume timer processing.
701		720
702	Effectively, all C<ev_timer> watchers will be delayed by the time spend	721	Effectively, all C<ev_timer> watchers will be delayed by the time spend
703	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers	722	between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
704	will be rescheduled (that is, they will lose any events that would have	723	will be rescheduled (that is, they will lose any events that would have
705	occured while suspended).	724	occurred while suspended).
706		725
707	After calling C<ev_suspend> you B<must not> call I<any> function on the	726	After calling C<ev_suspend> you B<must not> call I<any> function on the
708	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>	727	given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
709	without a previous call to C<ev_suspend>.	728	without a previous call to C<ev_suspend>.
710		729
711	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	730	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
712	event loop time (see C<ev_now_update>).	731	event loop time (see C<ev_now_update>).
713		732
714	=item ev_loop (loop, int flags)	733	=item ev_run (loop, int flags)
715		734
716	Finally, this is it, the event handler. This function usually is called	735	Finally, this is it, the event handler. This function usually is called
717	after you have initialised all your watchers and you want to start	736	after you have initialised all your watchers and you want to start
718	handling events.	737	handling events. It will ask the operating system for any new events, call
		738	the watcher callbacks, an then repeat the whole process indefinitely: This
		739	is why event loops are called I<loops>.
719		740
720	If the flags argument is specified as C<0>, it will not return until	741	If the flags argument is specified as C<0>, it will keep handling events
721	either no event watchers are active anymore or C<ev_unloop> was called.	742	until either no event watchers are active anymore or C<ev_break> was
		743	called.
722		744
723	Please note that an explicit C<ev_unloop> is usually better than	745	Please note that an explicit C<ev_break> is usually better than
724	relying on all watchers to be stopped when deciding when a program has	746	relying on all watchers to be stopped when deciding when a program has
725	finished (especially in interactive programs), but having a program	747	finished (especially in interactive programs), but having a program
726	that automatically loops as long as it has to and no longer by virtue	748	that automatically loops as long as it has to and no longer by virtue
727	of relying on its watchers stopping correctly, that is truly a thing of	749	of relying on its watchers stopping correctly, that is truly a thing of
728	beauty.	750	beauty.
729		751
730	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	752	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
731	those events and any already outstanding ones, but will not block your	753	those events and any already outstanding ones, but will not wait and
732	process in case there are no events and will return after one iteration of	754	block your process in case there are no events and will return after one
733	the loop.	755	iteration of the loop. This is sometimes useful to poll and handle new
		756	events while doing lengthy calculations, to keep the program responsive.
734		757
735	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	758	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
736	necessary) and will handle those and any already outstanding ones. It	759	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	760	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	761	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	762	user-registered callback will be called), and will return after one
740	iteration of the loop.	763	iteration of the loop.
741		764
742	This is useful if you are waiting for some external event in conjunction	765	This is useful if you are waiting for some external event in conjunction
743	with something not expressible using other libev watchers (i.e. "roll your	766	with something not expressible using other libev watchers (i.e. "roll your
744	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	767	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
745	usually a better approach for this kind of thing.	768	usually a better approach for this kind of thing.
746		769
747	Here are the gory details of what C<ev_loop> does:	770	Here are the gory details of what C<ev_run> does:
748		771
		772	- Increment loop depth.
		773	- Reset the ev_break status.
749	- Before the first iteration, call any pending watchers.	774	- Before the first iteration, call any pending watchers.
		775	LOOP:
750	* If EVFLAG_FORKCHECK was used, check for a fork.	776	- If EVFLAG_FORKCHECK was used, check for a fork.
751	- If a fork was detected (by any means), queue and call all fork watchers.	777	- If a fork was detected (by any means), queue and call all fork watchers.
752	- Queue and call all prepare watchers.	778	- Queue and call all prepare watchers.
		779	- If ev_break was called, goto FINISH.
753	- If we have been forked, detach and recreate the kernel state	780	- If we have been forked, detach and recreate the kernel state
754	as to not disturb the other process.	781	as to not disturb the other process.
755	- Update the kernel state with all outstanding changes.	782	- Update the kernel state with all outstanding changes.
756	- Update the "event loop time" (ev_now ()).	783	- Update the "event loop time" (ev_now ()).
757	- Calculate for how long to sleep or block, if at all	784	- Calculate for how long to sleep or block, if at all
758	(active idle watchers, EVLOOP_NONBLOCK or not having	785	(active idle watchers, EVRUN_NOWAIT or not having
759	any active watchers at all will result in not sleeping).	786	any active watchers at all will result in not sleeping).
760	- Sleep if the I/O and timer collect interval say so.	787	- Sleep if the I/O and timer collect interval say so.
		788	- Increment loop iteration counter.
761	- Block the process, waiting for any events.	789	- Block the process, waiting for any events.
762	- Queue all outstanding I/O (fd) events.	790	- Queue all outstanding I/O (fd) events.
763	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	791	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
764	- Queue all expired timers.	792	- Queue all expired timers.
765	- Queue all expired periodics.	793	- Queue all expired periodics.
766	- Unless any events are pending now, queue all idle watchers.	794	- Queue all idle watchers with priority higher than that of pending events.
767	- Queue all check watchers.	795	- Queue all check watchers.
768	- Call all queued watchers in reverse order (i.e. check watchers first).	796	- Call all queued watchers in reverse order (i.e. check watchers first).
769	Signals and child watchers are implemented as I/O watchers, and will	797	Signals and child watchers are implemented as I/O watchers, and will
770	be handled here by queueing them when their watcher gets executed.	798	be handled here by queueing them when their watcher gets executed.
771	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	799	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
772	were used, or there are no active watchers, return, otherwise	800	were used, or there are no active watchers, goto FINISH, otherwise
773	continue with step *.	801	continue with step LOOP.
		802	FINISH:
		803	- Reset the ev_break status iff it was EVBREAK_ONE.
		804	- Decrement the loop depth.
		805	- Return.
774		806
775	Example: Queue some jobs and then loop until no events are outstanding	807	Example: Queue some jobs and then loop until no events are outstanding
776	anymore.	808	anymore.
777		809
778	... queue jobs here, make sure they register event watchers as long	810	... 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..)	811	... as they still have work to do (even an idle watcher will do..)
780	ev_loop (my_loop, 0);	812	ev_run (my_loop, 0);
781	... jobs done or somebody called unloop. yeah!	813	... jobs done or somebody called unloop. yeah!
782		814
783	=item ev_unloop (loop, how)	815	=item ev_break (loop, how)
784		816
785	Can be used to make a call to C<ev_loop> return early (but only after it	817	Can be used to make a call to C<ev_run> return early (but only after it
786	has processed all outstanding events). The C<how> argument must be either	818	has processed all outstanding events). The C<how> argument must be either
787	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	819	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
788	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	820	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
789		821
790	This "unloop state" will be cleared when entering C<ev_loop> again.	822	This "unloop state" will be cleared when entering C<ev_run> again.
791		823
792	It is safe to call C<ev_unloop> from otuside any C<ev_loop> calls.	824	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
793		825
794	=item ev_ref (loop)	826	=item ev_ref (loop)
795		827
796	=item ev_unref (loop)	828	=item ev_unref (loop)
797		829
798	Ref/unref can be used to add or remove a reference count on the event	830	Ref/unref can be used to add or remove a reference count on the event
799	loop: Every watcher keeps one reference, and as long as the reference	831	loop: Every watcher keeps one reference, and as long as the reference
800	count is nonzero, C<ev_loop> will not return on its own.	832	count is nonzero, C<ev_run> will not return on its own.
801		833
802	This is useful when you have a watcher that you never intend to	834	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	835	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>	836	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
805	before stopping it.	837	before stopping it.
806		838
807	As an example, libev itself uses this for its internal signal pipe: It	839	As an example, libev itself uses this for its internal signal pipe: It
808	is not visible to the libev user and should not keep C<ev_loop> from	840	is not visible to the libev user and should not keep C<ev_run> from
809	exiting if no event watchers registered by it are active. It is also an	841	exiting if no event watchers registered by it are active. It is also an
810	excellent way to do this for generic recurring timers or from within	842	excellent way to do this for generic recurring timers or from within
811	third-party libraries. Just remember to I<unref after start> and I<ref	843	third-party libraries. Just remember to I<unref after start> and I<ref
812	before stop> (but only if the watcher wasn't active before, or was active	844	before stop> (but only if the watcher wasn't active before, or was active
813	before, respectively. Note also that libev might stop watchers itself	845	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>	846	(e.g. non-repeating timers) in which case you have to C<ev_ref>
815	in the callback).	847	in the callback).
816		848
817	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	849	Example: Create a signal watcher, but keep it from keeping C<ev_run>
818	running when nothing else is active.	850	running when nothing else is active.
819		851
820	ev_signal exitsig;	852	ev_signal exitsig;
821	ev_signal_init (&exitsig, sig_cb, SIGINT);	853	ev_signal_init (&exitsig, sig_cb, SIGINT);
822	ev_signal_start (loop, &exitsig);	854	ev_signal_start (loop, &exitsig);
…		…
867	usually doesn't make much sense to set it to a lower value than C<0.01>,	899	usually doesn't make much sense to set it to a lower value than C<0.01>,
868	as this approaches the timing granularity of most systems. Note that if	900	as this approaches the timing granularity of most systems. Note that if
869	you do transactions with the outside world and you can't increase the	901	you do transactions with the outside world and you can't increase the
870	parallelity, then this setting will limit your transaction rate (if you	902	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,	903	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).	904	then you can't do more than 100 transactions per second).
873		905
874	Setting the I<timeout collect interval> can improve the opportunity for	906	Setting the I<timeout collect interval> can improve the opportunity for
875	saving power, as the program will "bundle" timer callback invocations that	907	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	908	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	909	times the process sleeps and wakes up again. Another useful technique to
…		…
885	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	917	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
886		918
887	=item ev_invoke_pending (loop)	919	=item ev_invoke_pending (loop)
888		920
889	This call will simply invoke all pending watchers while resetting their	921	This call will simply invoke all pending watchers while resetting their
890	pending state. Normally, C<ev_loop> does this automatically when required,	922	pending state. Normally, C<ev_run> does this automatically when required,
891	but when overriding the invoke callback this call comes handy.	923	but when overriding the invoke callback this call comes handy. This
		924	function can be invoked from a watcher - this can be useful for example
		925	when you want to do some lengthy calculation and want to pass further
		926	event handling to another thread (you still have to make sure only one
		927	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
892		928
893	=item int ev_pending_count (loop)	929	=item int ev_pending_count (loop)
894		930
895	Returns the number of pending watchers - zero indicates that no watchers	931	Returns the number of pending watchers - zero indicates that no watchers
896	are pending.	932	are pending.
897		933
898	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	934	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
899		935
900	This overrides the invoke pending functionality of the loop: Instead of	936	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	937	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	938	this callback instead. This is useful, for example, when you want to
903	invoke the actual watchers inside another context (another thread etc.).	939	invoke the actual watchers inside another context (another thread etc.).
904		940
905	If you want to reset the callback, use C<ev_invoke_pending> as new	941	If you want to reset the callback, use C<ev_invoke_pending> as new
906	callback.	942	callback.
…		…
909		945
910	Sometimes you want to share the same loop between multiple threads. This	946	Sometimes you want to share the same loop between multiple threads. This
911	can be done relatively simply by putting mutex_lock/unlock calls around	947	can be done relatively simply by putting mutex_lock/unlock calls around
912	each call to a libev function.	948	each call to a libev function.
913		949
914	However, C<ev_loop> can run an indefinite time, so it is not feasible to	950	However, C<ev_run> can run an indefinite time, so it is not feasible
915	wait for it to return. One way around this is to wake up the loop via	951	to wait for it to return. One way around this is to wake up the event
916	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	952	loop via C<ev_break> and C<av_async_send>, another way is to set these
917	and I<acquire> callbacks on the loop.	953	I<release> and I<acquire> callbacks on the loop.
918		954
919	When set, then C<release> will be called just before the thread is	955	When set, then C<release> will be called just before the thread is
920	suspended waiting for new events, and C<acquire> is called just	956	suspended waiting for new events, and C<acquire> is called just
921	afterwards.	957	afterwards.
922		958
…		…
925		961
926	While event loop modifications are allowed between invocations of	962	While event loop modifications are allowed between invocations of
927	C<release> and C<acquire> (that's their only purpose after all), no	963	C<release> and C<acquire> (that's their only purpose after all), no
928	modifications done will affect the event loop, i.e. adding watchers will	964	modifications done will affect the event loop, i.e. adding watchers will
929	have no effect on the set of file descriptors being watched, or the time	965	have no effect on the set of file descriptors being watched, or the time
930	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	966	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
931	to take note of any changes you made.	967	to take note of any changes you made.
932		968
933	In theory, threads executing C<ev_loop> will be async-cancel safe between	969	In theory, threads executing C<ev_run> will be async-cancel safe between
934	invocations of C<release> and C<acquire>.	970	invocations of C<release> and C<acquire>.
935		971
936	See also the locking example in the C<THREADS> section later in this	972	See also the locking example in the C<THREADS> section later in this
937	document.	973	document.
938		974
…		…
947	These two functions can be used to associate arbitrary data with a loop,	983	These two functions can be used to associate arbitrary data with a loop,
948	and are intended solely for the C<invoke_pending_cb>, C<release> and	984	and are intended solely for the C<invoke_pending_cb>, C<release> and
949	C<acquire> callbacks described above, but of course can be (ab-)used for	985	C<acquire> callbacks described above, but of course can be (ab-)used for
950	any other purpose as well.	986	any other purpose as well.
951		987
952	=item ev_loop_verify (loop)	988	=item ev_verify (loop)
953		989
954	This function only does something when C<EV_VERIFY> support has been	990	This function only does something when C<EV_VERIFY> support has been
955	compiled in, which is the default for non-minimal builds. It tries to go	991	compiled in, which is the default for non-minimal builds. It tries to go
956	through all internal structures and checks them for validity. If anything	992	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	993	is found to be inconsistent, it will print an error message to standard
…		…
968		1004
969	In the following description, uppercase C<TYPE> in names stands for the	1005	In the following description, uppercase C<TYPE> in names stands for the
970	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1006	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
971	watchers and C<ev_io_start> for I/O watchers.	1007	watchers and C<ev_io_start> for I/O watchers.
972		1008
973	A watcher is a structure that you create and register to record your	1009	A watcher is an opaque structure that you allocate and register to record
974	interest in some event. For instance, if you want to wait for STDIN to	1010	your interest in some event. To make a concrete example, imagine you want
975	become readable, you would create an C<ev_io> watcher for that:	1011	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1012	for that:
976		1013
977	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1014	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
978	{	1015	{
979	ev_io_stop (w);	1016	ev_io_stop (w);
980	ev_unloop (loop, EVUNLOOP_ALL);	1017	ev_break (loop, EVBREAK_ALL);
981	}	1018	}
982		1019
983	struct ev_loop *loop = ev_default_loop (0);	1020	struct ev_loop *loop = ev_default_loop (0);
984		1021
985	ev_io stdin_watcher;	1022	ev_io stdin_watcher;
986		1023
987	ev_init (&stdin_watcher, my_cb);	1024	ev_init (&stdin_watcher, my_cb);
988	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1025	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
989	ev_io_start (loop, &stdin_watcher);	1026	ev_io_start (loop, &stdin_watcher);
990		1027
991	ev_loop (loop, 0);	1028	ev_run (loop, 0);
992		1029
993	As you can see, you are responsible for allocating the memory for your	1030	As you can see, you are responsible for allocating the memory for your
994	watcher structures (and it is I<usually> a bad idea to do this on the	1031	watcher structures (and it is I<usually> a bad idea to do this on the
995	stack).	1032	stack).
996		1033
997	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1034	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
998	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1035	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
999		1036
1000	Each watcher structure must be initialised by a call to C<ev_init	1037	Each watcher structure must be initialised by a call to C<ev_init (watcher
1001	(watcher *, callback)>, which expects a callback to be provided. This	1038	*, 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	1039	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	1040	time the event loop detects that the file descriptor given is readable
1004	is readable and/or writable).	1041	and/or writable).
1005		1042
1006	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1043	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1007	macro to configure it, with arguments specific to the watcher type. There	1044	macro to configure it, with arguments specific to the watcher type. There
1008	is also a macro to combine initialisation and setting in one call: C<<	1045	is also a macro to combine initialisation and setting in one call: C<<
1009	ev_TYPE_init (watcher *, callback, ...) >>.	1046	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1032	=item C<EV_WRITE>	1069	=item C<EV_WRITE>
1033		1070
1034	The file descriptor in the C<ev_io> watcher has become readable and/or	1071	The file descriptor in the C<ev_io> watcher has become readable and/or
1035	writable.	1072	writable.
1036		1073
1037	=item C<EV_TIMEOUT>	1074	=item C<EV_TIMER>
1038		1075
1039	The C<ev_timer> watcher has timed out.	1076	The C<ev_timer> watcher has timed out.
1040		1077
1041	=item C<EV_PERIODIC>	1078	=item C<EV_PERIODIC>
1042		1079
…		…
1060		1097
1061	=item C<EV_PREPARE>	1098	=item C<EV_PREPARE>
1062		1099
1063	=item C<EV_CHECK>	1100	=item C<EV_CHECK>
1064		1101
1065	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1102	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1066	to gather new events, and all C<ev_check> watchers are invoked just after	1103	to gather new events, and all C<ev_check> watchers are invoked just after
1067	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1104	C<ev_run> has gathered them, but before it invokes any callbacks for any
1068	received events. Callbacks of both watcher types can start and stop as	1105	received events. Callbacks of both watcher types can start and stop as
1069	many watchers as they want, and all of them will be taken into account	1106	many watchers as they want, and all of them will be taken into account
1070	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1107	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1071	C<ev_loop> from blocking).	1108	C<ev_run> from blocking).
1072		1109
1073	=item C<EV_EMBED>	1110	=item C<EV_EMBED>
1074		1111
1075	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1112	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1076		1113
…		…
1104	example it might indicate that a fd is readable or writable, and if your	1141	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	1142	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	1143	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	1144	programs, though, as the fd could already be closed and reused for another
1108	thing, so beware.	1145	thing, so beware.
		1146
		1147	=back
		1148
		1149	=head2 WATCHER STATES
		1150
		1151	There are various watcher states mentioned throughout this manual -
		1152	active, pending and so on. In this section these states and the rules to
		1153	transition between them will be described in more detail - and while these
		1154	rules might look complicated, they usually do "the right thing".
		1155
		1156	=over 4
		1157
		1158	=item initialiased
		1159
		1160	Before a watcher can be registered with the event looop it has to be
		1161	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1162	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1163
		1164	In this state it is simply some block of memory that is suitable for use
		1165	in an event loop. It can be moved around, freed, reused etc. at will.
		1166
		1167	=item started/running/active
		1168
		1169	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1170	property of the event loop, and is actively waiting for events. While in
		1171	this state it cannot be accessed (except in a few documented ways), moved,
		1172	freed or anything else - the only legal thing is to keep a pointer to it,
		1173	and call libev functions on it that are documented to work on active watchers.
		1174
		1175	=item pending
		1176
		1177	If a watcher is active and libev determines that an event it is interested
		1178	in has occurred (such as a timer expiring), it will become pending. It will
		1179	stay in this pending state until either it is stopped or its callback is
		1180	about to be invoked, so it is not normally pending inside the watcher
		1181	callback.
		1182
		1183	The watcher might or might not be active while it is pending (for example,
		1184	an expired non-repeating timer can be pending but no longer active). If it
		1185	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1186	but it is still property of the event loop at this time, so cannot be
		1187	moved, freed or reused. And if it is active the rules described in the
		1188	previous item still apply.
		1189
		1190	It is also possible to feed an event on a watcher that is not active (e.g.
		1191	via C<ev_feed_event>), in which case it becomes pending without being
		1192	active.
		1193
		1194	=item stopped
		1195
		1196	A watcher can be stopped implicitly by libev (in which case it might still
		1197	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1198	latter will clear any pending state the watcher might be in, regardless
		1199	of whether it was active or not, so stopping a watcher explicitly before
		1200	freeing it is often a good idea.
		1201
		1202	While stopped (and not pending) the watcher is essentially in the
		1203	initialised state, that is it can be reused, moved, modified in any way
		1204	you wish.
1109		1205
1110	=back	1206	=back
1111		1207
1112	=head2 GENERIC WATCHER FUNCTIONS	1208	=head2 GENERIC WATCHER FUNCTIONS
1113		1209
…		…
1375		1471
1376	For example, to emulate how many other event libraries handle priorities,	1472	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	1473	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	1474	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	1475	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	1476	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	1477	the lock-out case is known to be rare (which in turn is rare :), this is
1382	workable.	1478	workable.
1383		1479
1384	Usually, however, the lock-out model implemented that way will perform	1480	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,	1481	miserably under the type of load it was designed to handle. In that case,
…		…
1399	{	1495	{
1400	// stop the I/O watcher, we received the event, but	1496	// stop the I/O watcher, we received the event, but
1401	// are not yet ready to handle it.	1497	// are not yet ready to handle it.
1402	ev_io_stop (EV_A_ w);	1498	ev_io_stop (EV_A_ w);
1403		1499
1404	// start the idle watcher to ahndle the actual event.	1500	// start the idle watcher to handle the actual event.
1405	// it will not be executed as long as other watchers	1501	// it will not be executed as long as other watchers
1406	// with the default priority are receiving events.	1502	// with the default priority are receiving events.
1407	ev_idle_start (EV_A_ &idle);	1503	ev_idle_start (EV_A_ &idle);
1408	}	1504	}
1409		1505
…		…
1463		1559
1464	If you cannot use non-blocking mode, then force the use of a	1560	If you cannot use non-blocking mode, then force the use of a
1465	known-to-be-good backend (at the time of this writing, this includes only	1561	known-to-be-good backend (at the time of this writing, this includes only
1466	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file	1562	C<EVBACKEND_SELECT> and C<EVBACKEND_POLL>). The same applies to file
1467	descriptors for which non-blocking operation makes no sense (such as	1563	descriptors for which non-blocking operation makes no sense (such as
1468	files) - libev doesn't guarentee any specific behaviour in that case.	1564	files) - libev doesn't guarantee any specific behaviour in that case.
1469		1565
1470	Another thing you have to watch out for is that it is quite easy to	1566	Another thing you have to watch out for is that it is quite easy to
1471	receive "spurious" readiness notifications, that is your callback might	1567	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	1568	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	1569	because there is no data. Not only are some backends known to create a
…		…
1538		1634
1539	So when you encounter spurious, unexplained daemon exits, make sure you	1635	So when you encounter spurious, unexplained daemon exits, make sure you
1540	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1636	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1541	somewhere, as that would have given you a big clue).	1637	somewhere, as that would have given you a big clue).
1542		1638
		1639	=head3 The special problem of accept()ing when you can't
		1640
		1641	Many implementations of the POSIX C<accept> function (for example,
		1642	found in post-2004 Linux) have the peculiar behaviour of not removing a
		1643	connection from the pending queue in all error cases.
		1644
		1645	For example, larger servers often run out of file descriptors (because
		1646	of resource limits), causing C<accept> to fail with C<ENFILE> but not
		1647	rejecting the connection, leading to libev signalling readiness on
		1648	the next iteration again (the connection still exists after all), and
		1649	typically causing the program to loop at 100% CPU usage.
		1650
		1651	Unfortunately, the set of errors that cause this issue differs between
		1652	operating systems, there is usually little the app can do to remedy the
		1653	situation, and no known thread-safe method of removing the connection to
		1654	cope with overload is known (to me).
		1655
		1656	One of the easiest ways to handle this situation is to just ignore it
		1657	- when the program encounters an overload, it will just loop until the
		1658	situation is over. While this is a form of busy waiting, no OS offers an
		1659	event-based way to handle this situation, so it's the best one can do.
		1660
		1661	A better way to handle the situation is to log any errors other than
		1662	C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
		1663	messages, and continue as usual, which at least gives the user an idea of
		1664	what could be wrong ("raise the ulimit!"). For extra points one could stop
		1665	the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
		1666	usage.
		1667
		1668	If your program is single-threaded, then you could also keep a dummy file
		1669	descriptor for overload situations (e.g. by opening F</dev/null>), and
		1670	when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
		1671	close that fd, and create a new dummy fd. This will gracefully refuse
		1672	clients under typical overload conditions.
		1673
		1674	The last way to handle it is to simply log the error and C<exit>, as
		1675	is often done with C<malloc> failures, but this results in an easy
		1676	opportunity for a DoS attack.
1543		1677
1544	=head3 Watcher-Specific Functions	1678	=head3 Watcher-Specific Functions
1545		1679
1546	=over 4	1680	=over 4
1547		1681
…		…
1579	...	1713	...
1580	struct ev_loop *loop = ev_default_init (0);	1714	struct ev_loop *loop = ev_default_init (0);
1581	ev_io stdin_readable;	1715	ev_io stdin_readable;
1582	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1716	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1583	ev_io_start (loop, &stdin_readable);	1717	ev_io_start (loop, &stdin_readable);
1584	ev_loop (loop, 0);	1718	ev_run (loop, 0);
1585		1719
1586		1720
1587	=head2 C<ev_timer> - relative and optionally repeating timeouts	1721	=head2 C<ev_timer> - relative and optionally repeating timeouts
1588		1722
1589	Timer watchers are simple relative timers that generate an event after a	1723	Timer watchers are simple relative timers that generate an event after a
…		…
1598	The callback is guaranteed to be invoked only I<after> its timeout has	1732	The callback is guaranteed to be invoked only I<after> its timeout has
1599	passed (not I<at>, so on systems with very low-resolution clocks this	1733	passed (not I<at>, so on systems with very low-resolution clocks this
1600	might introduce a small delay). If multiple timers become ready during the	1734	might introduce a small delay). If multiple timers become ready during the
1601	same loop iteration then the ones with earlier time-out values are invoked	1735	same loop iteration then the ones with earlier time-out values are invoked
1602	before ones of the same priority with later time-out values (but this is	1736	before ones of the same priority with later time-out values (but this is
1603	no longer true when a callback calls C<ev_loop> recursively).	1737	no longer true when a callback calls C<ev_run> recursively).
1604		1738
1605	=head3 Be smart about timeouts	1739	=head3 Be smart about timeouts
1606		1740
1607	Many real-world problems involve some kind of timeout, usually for error	1741	Many real-world problems involve some kind of timeout, usually for error
1608	recovery. A typical example is an HTTP request - if the other side hangs,	1742	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1694	ev_tstamp timeout = last_activity + 60.;	1828	ev_tstamp timeout = last_activity + 60.;
1695		1829
1696	// if last_activity + 60. is older than now, we did time out	1830	// if last_activity + 60. is older than now, we did time out
1697	if (timeout < now)	1831	if (timeout < now)
1698	{	1832	{
1699	// timeout occured, take action	1833	// timeout occurred, take action
1700	}	1834	}
1701	else	1835	else
1702	{	1836	{
1703	// callback was invoked, but there was some activity, re-arm	1837	// callback was invoked, but there was some activity, re-arm
1704	// the watcher to fire in last_activity + 60, which is	1838	// the watcher to fire in last_activity + 60, which is
…		…
1726	to the current time (meaning we just have some activity :), then call the	1860	to the current time (meaning we just have some activity :), then call the
1727	callback, which will "do the right thing" and start the timer:	1861	callback, which will "do the right thing" and start the timer:
1728		1862
1729	ev_init (timer, callback);	1863	ev_init (timer, callback);
1730	last_activity = ev_now (loop);	1864	last_activity = ev_now (loop);
1731	callback (loop, timer, EV_TIMEOUT);	1865	callback (loop, timer, EV_TIMER);
1732		1866
1733	And when there is some activity, simply store the current time in	1867	And when there is some activity, simply store the current time in
1734	C<last_activity>, no libev calls at all:	1868	C<last_activity>, no libev calls at all:
1735		1869
1736	last_actiivty = ev_now (loop);	1870	last_activity = ev_now (loop);
1737		1871
1738	This technique is slightly more complex, but in most cases where the	1872	This technique is slightly more complex, but in most cases where the
1739	time-out is unlikely to be triggered, much more efficient.	1873	time-out is unlikely to be triggered, much more efficient.
1740		1874
1741	Changing the timeout is trivial as well (if it isn't hard-coded in the	1875	Changing the timeout is trivial as well (if it isn't hard-coded in the
…		…
1779		1913
1780	=head3 The special problem of time updates	1914	=head3 The special problem of time updates
1781		1915
1782	Establishing the current time is a costly operation (it usually takes at	1916	Establishing the current time is a costly operation (it usually takes at
1783	least two system calls): EV therefore updates its idea of the current	1917	least two system calls): EV therefore updates its idea of the current
1784	time only before and after C<ev_loop> collects new events, which causes a	1918	time only before and after C<ev_run> collects new events, which causes a
1785	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1919	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1786	lots of events in one iteration.	1920	lots of events in one iteration.
1787		1921
1788	The relative timeouts are calculated relative to the C<ev_now ()>	1922	The relative timeouts are calculated relative to the C<ev_now ()>
1789	time. This is usually the right thing as this timestamp refers to the time	1923	time. This is usually the right thing as this timestamp refers to the time
…		…
1906	}	2040	}
1907		2041
1908	ev_timer mytimer;	2042	ev_timer mytimer;
1909	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2043	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1910	ev_timer_again (&mytimer); /* start timer */	2044	ev_timer_again (&mytimer); /* start timer */
1911	ev_loop (loop, 0);	2045	ev_run (loop, 0);
1912		2046
1913	// and in some piece of code that gets executed on any "activity":	2047	// and in some piece of code that gets executed on any "activity":
1914	// reset the timeout to start ticking again at 10 seconds	2048	// reset the timeout to start ticking again at 10 seconds
1915	ev_timer_again (&mytimer);	2049	ev_timer_again (&mytimer);
1916		2050
…		…
1942		2076
1943	As with timers, the callback is guaranteed to be invoked only when the	2077	As with timers, the callback is guaranteed to be invoked only when the
1944	point in time where it is supposed to trigger has passed. If multiple	2078	point in time where it is supposed to trigger has passed. If multiple
1945	timers become ready during the same loop iteration then the ones with	2079	timers become ready during the same loop iteration then the ones with
1946	earlier time-out values are invoked before ones with later time-out values	2080	earlier time-out values are invoked before ones with later time-out values
1947	(but this is no longer true when a callback calls C<ev_loop> recursively).	2081	(but this is no longer true when a callback calls C<ev_run> recursively).
1948		2082
1949	=head3 Watcher-Specific Functions and Data Members	2083	=head3 Watcher-Specific Functions and Data Members
1950		2084
1951	=over 4	2085	=over 4
1952		2086
…		…
2080	Example: Call a callback every hour, or, more precisely, whenever the	2214	Example: Call a callback every hour, or, more precisely, whenever the
2081	system time is divisible by 3600. The callback invocation times have	2215	system time is divisible by 3600. The callback invocation times have
2082	potentially a lot of jitter, but good long-term stability.	2216	potentially a lot of jitter, but good long-term stability.
2083		2217
2084	static void	2218	static void
2085	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2219	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
2086	{	2220	{
2087	... its now a full hour (UTC, or TAI or whatever your clock follows)	2221	... its now a full hour (UTC, or TAI or whatever your clock follows)
2088	}	2222	}
2089		2223
2090	ev_periodic hourly_tick;	2224	ev_periodic hourly_tick;
…		…
2190	Example: Try to exit cleanly on SIGINT.	2324	Example: Try to exit cleanly on SIGINT.
2191		2325
2192	static void	2326	static void
2193	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2327	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2194	{	2328	{
2195	ev_unloop (loop, EVUNLOOP_ALL);	2329	ev_break (loop, EVBREAK_ALL);
2196	}	2330	}
2197		2331
2198	ev_signal signal_watcher;	2332	ev_signal signal_watcher;
2199	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2333	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2200	ev_signal_start (loop, &signal_watcher);	2334	ev_signal_start (loop, &signal_watcher);
…		…
2586		2720
2587	Prepare and check watchers are usually (but not always) used in pairs:	2721	Prepare and check watchers are usually (but not always) used in pairs:
2588	prepare watchers get invoked before the process blocks and check watchers	2722	prepare watchers get invoked before the process blocks and check watchers
2589	afterwards.	2723	afterwards.
2590		2724
2591	You I<must not> call C<ev_loop> or similar functions that enter	2725	You I<must not> call C<ev_run> or similar functions that enter
2592	the current event loop from either C<ev_prepare> or C<ev_check>	2726	the current event loop from either C<ev_prepare> or C<ev_check>
2593	watchers. Other loops than the current one are fine, however. The	2727	watchers. Other loops than the current one are fine, however. The
2594	rationale behind this is that you do not need to check for recursion in	2728	rationale behind this is that you do not need to check for recursion in
2595	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2729	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2596	C<ev_check> so if you have one watcher of each kind they will always be	2730	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2764		2898
2765	if (timeout >= 0)	2899	if (timeout >= 0)
2766	// create/start timer	2900	// create/start timer
2767		2901
2768	// poll	2902	// poll
2769	ev_loop (EV_A_ 0);	2903	ev_run (EV_A_ 0);
2770		2904
2771	// stop timer again	2905	// stop timer again
2772	if (timeout >= 0)	2906	if (timeout >= 0)
2773	ev_timer_stop (EV_A_ &to);	2907	ev_timer_stop (EV_A_ &to);
2774		2908
…		…
2852	if you do not want that, you need to temporarily stop the embed watcher).	2986	if you do not want that, you need to temporarily stop the embed watcher).
2853		2987
2854	=item ev_embed_sweep (loop, ev_embed *)	2988	=item ev_embed_sweep (loop, ev_embed *)
2855		2989
2856	Make a single, non-blocking sweep over the embedded loop. This works	2990	Make a single, non-blocking sweep over the embedded loop. This works
2857	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2991	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2858	appropriate way for embedded loops.	2992	appropriate way for embedded loops.
2859		2993
2860	=item struct ev_loop *other [read-only]	2994	=item struct ev_loop *other [read-only]
2861		2995
2862	The embedded event loop.	2996	The embedded event loop.
…		…
2922	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3056	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2923	handlers will be invoked, too, of course.	3057	handlers will be invoked, too, of course.
2924		3058
2925	=head3 The special problem of life after fork - how is it possible?	3059	=head3 The special problem of life after fork - how is it possible?
2926		3060
2927	Most uses of C<fork()> consist of forking, then some simple calls to ste	3061	Most uses of C<fork()> consist of forking, then some simple calls to set
2928	up/change the process environment, followed by a call to C<exec()>. This	3062	up/change the process environment, followed by a call to C<exec()>. This
2929	sequence should be handled by libev without any problems.	3063	sequence should be handled by libev without any problems.
2930		3064
2931	This changes when the application actually wants to do event handling	3065	This changes when the application actually wants to do event handling
2932	in the child, or both parent in child, in effect "continuing" after the	3066	in the child, or both parent in child, in effect "continuing" after the
…		…
2948	disadvantage of having to use multiple event loops (which do not support	3082	disadvantage of having to use multiple event loops (which do not support
2949	signal watchers).	3083	signal watchers).
2950		3084
2951	When this is not possible, or you want to use the default loop for	3085	When this is not possible, or you want to use the default loop for
2952	other reasons, then in the process that wants to start "fresh", call	3086	other reasons, then in the process that wants to start "fresh", call
2953	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3087	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2954	the default loop will "orphan" (not stop) all registered watchers, so you	3088	Destroying the default loop will "orphan" (not stop) all registered
2955	have to be careful not to execute code that modifies those watchers. Note	3089	watchers, so you have to be careful not to execute code that modifies
2956	also that in that case, you have to re-register any signal watchers.	3090	those watchers. Note also that in that case, you have to re-register any
		3091	signal watchers.
2957		3092
2958	=head3 Watcher-Specific Functions and Data Members	3093	=head3 Watcher-Specific Functions and Data Members
2959		3094
2960	=over 4	3095	=over 4
2961		3096
…		…
2966	believe me.	3101	believe me.
2967		3102
2968	=back	3103	=back
2969		3104
2970		3105
2971	=head2 C<ev_async> - how to wake up another event loop	3106	=head2 C<ev_async> - how to wake up an event loop
2972		3107
2973	In general, you cannot use an C<ev_loop> from multiple threads or other	3108	In general, you cannot use an C<ev_run> from multiple threads or other
2974	asynchronous sources such as signal handlers (as opposed to multiple event	3109	asynchronous sources such as signal handlers (as opposed to multiple event
2975	loops - those are of course safe to use in different threads).	3110	loops - those are of course safe to use in different threads).
2976		3111
2977	Sometimes, however, you need to wake up another event loop you do not	3112	Sometimes, however, you need to wake up an event loop you do not control,
2978	control, for example because it belongs to another thread. This is what	3113	for example because it belongs to another thread. This is what C<ev_async>
2979	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3114	watchers do: as long as the C<ev_async> watcher is active, you can signal
2980	can signal it by calling C<ev_async_send>, which is thread- and signal	3115	it by calling C<ev_async_send>, which is thread- and signal safe.
2981	safe.
2982		3116
2983	This functionality is very similar to C<ev_signal> watchers, as signals,	3117	This functionality is very similar to C<ev_signal> watchers, as signals,
2984	too, are asynchronous in nature, and signals, too, will be compressed	3118	too, are asynchronous in nature, and signals, too, will be compressed
2985	(i.e. the number of callback invocations may be less than the number of	3119	(i.e. the number of callback invocations may be less than the number of
2986	C<ev_async_sent> calls).	3120	C<ev_async_sent> calls).
…		…
3141		3275
3142	If C<timeout> is less than 0, then no timeout watcher will be	3276	If C<timeout> is less than 0, then no timeout watcher will be
3143	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	3277	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
3144	repeat = 0) will be started. C<0> is a valid timeout.	3278	repeat = 0) will be started. C<0> is a valid timeout.
3145		3279
3146	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	3280	The callback has the type C<void (*cb)(int revents, void *arg)> and is
3147	passed an C<revents> set like normal event callbacks (a combination of	3281	passed an C<revents> set like normal event callbacks (a combination of
3148	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	3282	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
3149	value passed to C<ev_once>. Note that it is possible to receive I<both>	3283	value passed to C<ev_once>. Note that it is possible to receive I<both>
3150	a timeout and an io event at the same time - you probably should give io	3284	a timeout and an io event at the same time - you probably should give io
3151	events precedence.	3285	events precedence.
3152		3286
3153	Example: wait up to ten seconds for data to appear on STDIN_FILENO.	3287	Example: wait up to ten seconds for data to appear on STDIN_FILENO.
3154		3288
3155	static void stdin_ready (int revents, void *arg)	3289	static void stdin_ready (int revents, void *arg)
3156	{	3290	{
3157	if (revents & EV_READ)	3291	if (revents & EV_READ)
3158	/* stdin might have data for us, joy! */;	3292	/* stdin might have data for us, joy! */;
3159	else if (revents & EV_TIMEOUT)	3293	else if (revents & EV_TIMER)
3160	/* doh, nothing entered */;	3294	/* doh, nothing entered */;
3161	}	3295	}
3162		3296
3163	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	3297	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3164		3298
…		…
3298	myclass obj;	3432	myclass obj;
3299	ev::io iow;	3433	ev::io iow;
3300	iow.set <myclass, &myclass::io_cb> (&obj);	3434	iow.set <myclass, &myclass::io_cb> (&obj);
3301		3435
3302	=item w->set (object *)	3436	=item w->set (object *)
3303
3304	This is an B<experimental> feature that might go away in a future version.
3305		3437
3306	This is a variation of a method callback - leaving out the method to call	3438	This is a variation of a method callback - leaving out the method to call
3307	will default the method to C<operator ()>, which makes it possible to use	3439	will default the method to C<operator ()>, which makes it possible to use
3308	functor objects without having to manually specify the C<operator ()> all	3440	functor objects without having to manually specify the C<operator ()> all
3309	the time. Incidentally, you can then also leave out the template argument	3441	the time. Incidentally, you can then also leave out the template argument
…		…
3349	Associates a different C<struct ev_loop> with this watcher. You can only	3481	Associates a different C<struct ev_loop> with this watcher. You can only
3350	do this when the watcher is inactive (and not pending either).	3482	do this when the watcher is inactive (and not pending either).
3351		3483
3352	=item w->set ([arguments])	3484	=item w->set ([arguments])
3353		3485
3354	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3486	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3355	called at least once. Unlike the C counterpart, an active watcher gets	3487	method or a suitable start method must be called at least once. Unlike the
3356	automatically stopped and restarted when reconfiguring it with this	3488	C counterpart, an active watcher gets automatically stopped and restarted
3357	method.	3489	when reconfiguring it with this method.
3358		3490
3359	=item w->start ()	3491	=item w->start ()
3360		3492
3361	Starts the watcher. Note that there is no C<loop> argument, as the	3493	Starts the watcher. Note that there is no C<loop> argument, as the
3362	constructor already stores the event loop.	3494	constructor already stores the event loop.
3363		3495
		3496	=item w->start ([arguments])
		3497
		3498	Instead of calling C<set> and C<start> methods separately, it is often
		3499	convenient to wrap them in one call. Uses the same type of arguments as
		3500	the configure C<set> method of the watcher.
		3501
3364	=item w->stop ()	3502	=item w->stop ()
3365		3503
3366	Stops the watcher if it is active. Again, no C<loop> argument.	3504	Stops the watcher if it is active. Again, no C<loop> argument.
3367		3505
3368	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3506	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3380		3518
3381	=back	3519	=back
3382		3520
3383	=back	3521	=back
3384		3522
3385	Example: Define a class with an IO and idle watcher, start one of them in	3523	Example: Define a class with two I/O and idle watchers, start the I/O
3386	the constructor.	3524	watchers in the constructor.
3387		3525
3388	class myclass	3526	class myclass
3389	{	3527	{
3390	ev::io io ; void io_cb (ev::io &w, int revents);	3528	ev::io io ; void io_cb (ev::io &w, int revents);
		3529	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3391	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3530	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3392		3531
3393	myclass (int fd)	3532	myclass (int fd)
3394	{	3533	{
3395	io .set <myclass, &myclass::io_cb > (this);	3534	io .set <myclass, &myclass::io_cb > (this);
		3535	io2 .set <myclass, &myclass::io2_cb > (this);
3396	idle.set <myclass, &myclass::idle_cb> (this);	3536	idle.set <myclass, &myclass::idle_cb> (this);
3397		3537
3398	io.start (fd, ev::READ);	3538	io.set (fd, ev::WRITE); // configure the watcher
		3539	io.start (); // start it whenever convenient
		3540
		3541	io2.start (fd, ev::READ); // set + start in one call
3399	}	3542	}
3400	};	3543	};
3401		3544
3402		3545
3403	=head1 OTHER LANGUAGE BINDINGS	3546	=head1 OTHER LANGUAGE BINDINGS
…		…
3477	loop argument"). The C<EV_A> form is used when this is the sole argument,	3620	loop argument"). The C<EV_A> form is used when this is the sole argument,
3478	C<EV_A_> is used when other arguments are following. Example:	3621	C<EV_A_> is used when other arguments are following. Example:
3479		3622
3480	ev_unref (EV_A);	3623	ev_unref (EV_A);
3481	ev_timer_add (EV_A_ watcher);	3624	ev_timer_add (EV_A_ watcher);
3482	ev_loop (EV_A_ 0);	3625	ev_run (EV_A_ 0);
3483		3626
3484	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3627	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3485	which is often provided by the following macro.	3628	which is often provided by the following macro.
3486		3629
3487	=item C<EV_P>, C<EV_P_>	3630	=item C<EV_P>, C<EV_P_>
…		…
3527	}	3670	}
3528		3671
3529	ev_check check;	3672	ev_check check;
3530	ev_check_init (&check, check_cb);	3673	ev_check_init (&check, check_cb);
3531	ev_check_start (EV_DEFAULT_ &check);	3674	ev_check_start (EV_DEFAULT_ &check);
3532	ev_loop (EV_DEFAULT_ 0);	3675	ev_run (EV_DEFAULT_ 0);
3533		3676
3534	=head1 EMBEDDING	3677	=head1 EMBEDDING
3535		3678
3536	Libev can (and often is) directly embedded into host	3679	Libev can (and often is) directly embedded into host
3537	applications. Examples of applications that embed it include the Deliantra	3680	applications. Examples of applications that embed it include the Deliantra
…		…
3622	define before including (or compiling) any of its files. The default in	3765	define before including (or compiling) any of its files. The default in
3623	the absence of autoconf is documented for every option.	3766	the absence of autoconf is documented for every option.
3624		3767
3625	Symbols marked with "(h)" do not change the ABI, and can have different	3768	Symbols marked with "(h)" do not change the ABI, and can have different
3626	values when compiling libev vs. including F<ev.h>, so it is permissible	3769	values when compiling libev vs. including F<ev.h>, so it is permissible
3627	to redefine them before including F<ev.h> without breakign compatibility	3770	to redefine them before including F<ev.h> without breaking compatibility
3628	to a compiled library. All other symbols change the ABI, which means all	3771	to a compiled library. All other symbols change the ABI, which means all
3629	users of libev and the libev code itself must be compiled with compatible	3772	users of libev and the libev code itself must be compiled with compatible
3630	settings.	3773	settings.
3631		3774
3632	=over 4	3775	=over 4
		3776
		3777	=item EV_COMPAT3 (h)
		3778
		3779	Backwards compatibility is a major concern for libev. This is why this
		3780	release of libev comes with wrappers for the functions and symbols that
		3781	have been renamed between libev version 3 and 4.
		3782
		3783	You can disable these wrappers (to test compatibility with future
		3784	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3785	sources. This has the additional advantage that you can drop the C<struct>
		3786	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3787	typedef in that case.
		3788
		3789	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3790	and in some even more future version the compatibility code will be
		3791	removed completely.
3633		3792
3634	=item EV_STANDALONE (h)	3793	=item EV_STANDALONE (h)
3635		3794
3636	Must always be C<1> if you do not use autoconf configuration, which	3795	Must always be C<1> if you do not use autoconf configuration, which
3637	keeps libev from including F<config.h>, and it also defines dummy	3796	keeps libev from including F<config.h>, and it also defines dummy
…		…
3838	fine.	3997	fine.
3839		3998
3840	If your embedding application does not need any priorities, defining these	3999	If your embedding application does not need any priorities, defining these
3841	both to C<0> will save some memory and CPU.	4000	both to C<0> will save some memory and CPU.
3842		4001
3843	=item EV_PERIODIC_ENABLE	4002	=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
		4003	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
		4004	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3844		4005
3845	If undefined or defined to be C<1>, then periodic timers are supported. If	4006	If undefined or defined to be C<1> (and the platform supports it), then
3846	defined to be C<0>, then they are not. Disabling them saves a few kB of	4007	the respective watcher type is supported. If defined to be C<0>, then it
3847	code.	4008	is not. Disabling watcher types mainly saves code size.
3848		4009
3849	=item EV_IDLE_ENABLE	4010	=item EV_FEATURES
3850
3851	If undefined or defined to be C<1>, then idle watchers are supported. If
3852	defined to be C<0>, then they are not. Disabling them saves a few kB of
3853	code.
3854
3855	=item EV_EMBED_ENABLE
3856
3857	If undefined or defined to be C<1>, then embed watchers are supported. If
3858	defined to be C<0>, then they are not. Embed watchers rely on most other
3859	watcher types, which therefore must not be disabled.
3860
3861	=item EV_STAT_ENABLE
3862
3863	If undefined or defined to be C<1>, then stat watchers are supported. If
3864	defined to be C<0>, then they are not.
3865
3866	=item EV_FORK_ENABLE
3867
3868	If undefined or defined to be C<1>, then fork watchers are supported. If
3869	defined to be C<0>, then they are not.
3870
3871	=item EV_SIGNAL_ENABLE
3872
3873	If undefined or defined to be C<1>, then signal watchers are supported. If
3874	defined to be C<0>, then they are not.
3875
3876	=item EV_ASYNC_ENABLE
3877
3878	If undefined or defined to be C<1>, then async watchers are supported. If
3879	defined to be C<0>, then they are not.
3880
3881	=item EV_CHILD_ENABLE
3882
3883	If undefined or defined to be C<1> (and C<_WIN32> is not defined), then
3884	child watchers are supported. If defined to be C<0>, then they are not.
3885
3886	=item EV_MINIMAL
3887		4011
3888	If you need to shave off some kilobytes of code at the expense of some	4012	If you need to shave off some kilobytes of code at the expense of some
3889	speed (but with the full API), define this symbol to C<1>. Currently this	4013	speed (but with the full API), you can define this symbol to request
3890	is used to override some inlining decisions, saves roughly 30% code size	4014	certain subsets of functionality. The default is to enable all features
3891	on amd64. It also selects a much smaller 2-heap for timer management over	4015	that can be enabled on the platform.
3892	the default 4-heap.
3893		4016
3894	You can save even more by disabling watcher types you do not need	4017	A typical way to use this symbol is to define it to C<0> (or to a bitset
3895	and setting C<EV_MAXPRI> == C<EV_MINPRI>. Also, disabling C<assert>	4018	with some broad features you want) and then selectively re-enable
3896	(C<-DNDEBUG>) will usually reduce code size a lot. Disabling inotify,	4019	additional parts you want, for example if you want everything minimal,
3897	eventfd and signalfd will further help, and disabling backends one doesn't	4020	but multiple event loop support, async and child watchers and the poll
3898	need (e.g. poll, epoll, kqueue, ports) will help further.	4021	backend, use this:
3899		4022
3900	Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to	4023	#define EV_FEATURES 0
3901	provide a bare-bones event library. See C<ev.h> for details on what parts
3902	of the API are still available, and do not complain if this subset changes
3903	over time.
3904
3905	This example set of settings reduces the compiled size of libev from 24Kb
3906	to 8Kb on my GNU/Linux amd64 system (and leaves little in - there is also
3907	an effect on the amount of memory used). With an intelligent-enough linker
3908	further unused functions might be left out as well automatically.
3909
3910	// tuning and API changes
3911	#define EV_MINIMAL 2
3912	#define EV_MULTIPLICITY 0	4024	#define EV_MULTIPLICITY 1
3913	#define EV_MINPRI 0
3914	#define EV_MAXPRI 0
3915
3916	// OS-specific backends
3917	#define EV_USE_INOTIFY 0
3918	#define EV_USE_EVENTFD 0
3919	#define EV_USE_SIGNALFD 0
3920	#define EV_USE_REALTIME 0
3921	#define EV_USE_MONOTONIC 0
3922	#define EV_USE_CLOCK_SYSCALL 0
3923
3924	// disable all backends except select
3925	#define EV_USE_POLL 0	4025	#define EV_USE_POLL 1
3926	#define EV_USE_PORT 0
3927	#define EV_USE_KQUEUE 0
3928	#define EV_USE_EPOLL 0
3929
3930	// disable all watcher types that cna be disabled
3931	#define EV_STAT_ENABLE 0
3932	#define EV_PERIODIC_ENABLE 0
3933	#define EV_IDLE_ENABLE 0
3934	#define EV_FORK_ENABLE 0
3935	#define EV_SIGNAL_ENABLE 0
3936	#define EV_CHILD_ENABLE 0	4026	#define EV_CHILD_ENABLE 1
3937	#define EV_ASYNC_ENABLE 0	4027	#define EV_ASYNC_ENABLE 1
3938	#define EV_EMBED_ENABLE 0	4028
		4029	The actual value is a bitset, it can be a combination of the following
		4030	values:
		4031
		4032	=over 4
		4033
		4034	=item C<1> - faster/larger code
		4035
		4036	Use larger code to speed up some operations.
		4037
		4038	Currently this is used to override some inlining decisions (enlarging the
		4039	code size by roughly 30% on amd64).
		4040
		4041	When optimising for size, use of compiler flags such as C<-Os> with
		4042	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
		4043	assertions.
		4044
		4045	=item C<2> - faster/larger data structures
		4046
		4047	Replaces the small 2-heap for timer management by a faster 4-heap, larger
		4048	hash table sizes and so on. This will usually further increase code size
		4049	and can additionally have an effect on the size of data structures at
		4050	runtime.
		4051
		4052	=item C<4> - full API configuration
		4053
		4054	This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
		4055	enables multiplicity (C<EV_MULTIPLICITY>=1).
		4056
		4057	=item C<8> - full API
		4058
		4059	This enables a lot of the "lesser used" API functions. See C<ev.h> for
		4060	details on which parts of the API are still available without this
		4061	feature, and do not complain if this subset changes over time.
		4062
		4063	=item C<16> - enable all optional watcher types
		4064
		4065	Enables all optional watcher types. If you want to selectively enable
		4066	only some watcher types other than I/O and timers (e.g. prepare,
		4067	embed, async, child...) you can enable them manually by defining
		4068	C<EV_watchertype_ENABLE> to C<1> instead.
		4069
		4070	=item C<32> - enable all backends
		4071
		4072	This enables all backends - without this feature, you need to enable at
		4073	least one backend manually (C<EV_USE_SELECT> is a good choice).
		4074
		4075	=item C<64> - enable OS-specific "helper" APIs
		4076
		4077	Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
		4078	default.
		4079
		4080	=back
		4081
		4082	Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
		4083	reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
		4084	code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
		4085	watchers, timers and monotonic clock support.
		4086
		4087	With an intelligent-enough linker (gcc+binutils are intelligent enough
		4088	when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
		4089	your program might be left out as well - a binary starting a timer and an
		4090	I/O watcher then might come out at only 5Kb.
3939		4091
3940	=item EV_AVOID_STDIO	4092	=item EV_AVOID_STDIO
3941		4093
3942	If this is set to C<1> at compiletime, then libev will avoid using stdio	4094	If this is set to C<1> at compiletime, then libev will avoid using stdio
3943	functions (printf, scanf, perror etc.). This will increase the codesize	4095	functions (printf, scanf, perror etc.). This will increase the code size
3944	somewhat, but if your program doesn't otherwise depend on stdio and your	4096	somewhat, but if your program doesn't otherwise depend on stdio and your
3945	libc allows it, this avoids linking in the stdio library which is quite	4097	libc allows it, this avoids linking in the stdio library which is quite
3946	big.	4098	big.
3947		4099
3948	Note that error messages might become less precise when this option is	4100	Note that error messages might become less precise when this option is
…		…
3952		4104
3953	The highest supported signal number, +1 (or, the number of	4105	The highest supported signal number, +1 (or, the number of
3954	signals): Normally, libev tries to deduce the maximum number of signals	4106	signals): Normally, libev tries to deduce the maximum number of signals
3955	automatically, but sometimes this fails, in which case it can be	4107	automatically, but sometimes this fails, in which case it can be
3956	specified. Also, using a lower number than detected (C<32> should be	4108	specified. Also, using a lower number than detected (C<32> should be
3957	good for about any system in existance) can save some memory, as libev	4109	good for about any system in existence) can save some memory, as libev
3958	statically allocates some 12-24 bytes per signal number.	4110	statically allocates some 12-24 bytes per signal number.
3959		4111
3960	=item EV_PID_HASHSIZE	4112	=item EV_PID_HASHSIZE
3961		4113
3962	C<ev_child> watchers use a small hash table to distribute workload by	4114	C<ev_child> watchers use a small hash table to distribute workload by
3963	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	4115	pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
3964	than enough. If you need to manage thousands of children you might want to	4116	usually more than enough. If you need to manage thousands of children you
3965	increase this value (I<must> be a power of two).	4117	might want to increase this value (I<must> be a power of two).
3966		4118
3967	=item EV_INOTIFY_HASHSIZE	4119	=item EV_INOTIFY_HASHSIZE
3968		4120
3969	C<ev_stat> watchers use a small hash table to distribute workload by	4121	C<ev_stat> watchers use a small hash table to distribute workload by
3970	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	4122	inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
3971	usually more than enough. If you need to manage thousands of C<ev_stat>	4123	disabled), usually more than enough. If you need to manage thousands of
3972	watchers you might want to increase this value (I<must> be a power of	4124	C<ev_stat> watchers you might want to increase this value (I<must> be a
3973	two).	4125	power of two).
3974		4126
3975	=item EV_USE_4HEAP	4127	=item EV_USE_4HEAP
3976		4128
3977	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4129	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3978	timer and periodics heaps, libev uses a 4-heap when this symbol is defined	4130	timer and periodics heaps, libev uses a 4-heap when this symbol is defined
3979	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably	4131	to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
3980	faster performance with many (thousands) of watchers.	4132	faster performance with many (thousands) of watchers.
3981		4133
3982	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4134	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3983	(disabled).	4135	will be C<0>.
3984		4136
3985	=item EV_HEAP_CACHE_AT	4137	=item EV_HEAP_CACHE_AT
3986		4138
3987	Heaps are not very cache-efficient. To improve the cache-efficiency of the	4139	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3988	timer and periodics heaps, libev can cache the timestamp (I<at>) within	4140	timer and periodics heaps, libev can cache the timestamp (I<at>) within
3989	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	4141	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3990	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	4142	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3991	but avoids random read accesses on heap changes. This improves performance	4143	but avoids random read accesses on heap changes. This improves performance
3992	noticeably with many (hundreds) of watchers.	4144	noticeably with many (hundreds) of watchers.
3993		4145
3994	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	4146	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
3995	(disabled).	4147	will be C<0>.
3996		4148
3997	=item EV_VERIFY	4149	=item EV_VERIFY
3998		4150
3999	Controls how much internal verification (see C<ev_loop_verify ()>) will	4151	Controls how much internal verification (see C<ev_verify ()>) will
4000	be done: If set to C<0>, no internal verification code will be compiled	4152	be done: If set to C<0>, no internal verification code will be compiled
4001	in. If set to C<1>, then verification code will be compiled in, but not	4153	in. If set to C<1>, then verification code will be compiled in, but not
4002	called. If set to C<2>, then the internal verification code will be	4154	called. If set to C<2>, then the internal verification code will be
4003	called once per loop, which can slow down libev. If set to C<3>, then the	4155	called once per loop, which can slow down libev. If set to C<3>, then the
4004	verification code will be called very frequently, which will slow down	4156	verification code will be called very frequently, which will slow down
4005	libev considerably.	4157	libev considerably.
4006		4158
4007	The default is C<1>, unless C<EV_MINIMAL> is set, in which case it will be	4159	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4008	C<0>.	4160	will be C<0>.
4009		4161
4010	=item EV_COMMON	4162	=item EV_COMMON
4011		4163
4012	By default, all watchers have a C<void *data> member. By redefining	4164	By default, all watchers have a C<void *data> member. By redefining
4013	this macro to a something else you can include more and other types of	4165	this macro to something else you can include more and other types of
4014	members. You have to define it each time you include one of the files,	4166	members. You have to define it each time you include one of the files,
4015	though, and it must be identical each time.	4167	though, and it must be identical each time.
4016		4168
4017	For example, the perl EV module uses something like this:	4169	For example, the perl EV module uses something like this:
4018		4170
…		…
4071	file.	4223	file.
4072		4224
4073	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	4225	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
4074	that everybody includes and which overrides some configure choices:	4226	that everybody includes and which overrides some configure choices:
4075		4227
4076	#define EV_MINIMAL 1	4228	#define EV_FEATURES 8
4077	#define EV_USE_POLL 0	4229	#define EV_USE_SELECT 1
4078	#define EV_MULTIPLICITY 0
4079	#define EV_PERIODIC_ENABLE 0	4230	#define EV_PREPARE_ENABLE 1
		4231	#define EV_IDLE_ENABLE 1
4080	#define EV_STAT_ENABLE 0	4232	#define EV_SIGNAL_ENABLE 1
4081	#define EV_FORK_ENABLE 0	4233	#define EV_CHILD_ENABLE 1
		4234	#define EV_USE_STDEXCEPT 0
4082	#define EV_CONFIG_H <config.h>	4235	#define EV_CONFIG_H <config.h>
4083	#define EV_MINPRI 0
4084	#define EV_MAXPRI 0
4085		4236
4086	#include "ev++.h"	4237	#include "ev++.h"
4087		4238
4088	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	4239	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
4089		4240
…		…
4220	userdata *u = ev_userdata (EV_A);	4371	userdata *u = ev_userdata (EV_A);
4221	pthread_mutex_lock (&u->lock);	4372	pthread_mutex_lock (&u->lock);
4222	}	4373	}
4223		4374
4224	The event loop thread first acquires the mutex, and then jumps straight	4375	The event loop thread first acquires the mutex, and then jumps straight
4225	into C<ev_loop>:	4376	into C<ev_run>:
4226		4377
4227	void *	4378	void *
4228	l_run (void *thr_arg)	4379	l_run (void *thr_arg)
4229	{	4380	{
4230	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4381	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4231		4382
4232	l_acquire (EV_A);	4383	l_acquire (EV_A);
4233	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4384	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4234	ev_loop (EV_A_ 0);	4385	ev_run (EV_A_ 0);
4235	l_release (EV_A);	4386	l_release (EV_A);
4236		4387
4237	return 0;	4388	return 0;
4238	}	4389	}
4239		4390
…		…
4291		4442
4292	=head3 COROUTINES	4443	=head3 COROUTINES
4293		4444
4294	Libev is very accommodating to coroutines ("cooperative threads"):	4445	Libev is very accommodating to coroutines ("cooperative threads"):
4295	libev fully supports nesting calls to its functions from different	4446	libev fully supports nesting calls to its functions from different
4296	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4447	coroutines (e.g. you can call C<ev_run> on the same loop from two
4297	different coroutines, and switch freely between both coroutines running	4448	different coroutines, and switch freely between both coroutines running
4298	the loop, as long as you don't confuse yourself). The only exception is	4449	the loop, as long as you don't confuse yourself). The only exception is
4299	that you must not do this from C<ev_periodic> reschedule callbacks.	4450	that you must not do this from C<ev_periodic> reschedule callbacks.
4300		4451
4301	Care has been taken to ensure that libev does not keep local state inside	4452	Care has been taken to ensure that libev does not keep local state inside
4302	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4453	C<ev_run>, and other calls do not usually allow for coroutine switches as
4303	they do not call any callbacks.	4454	they do not call any callbacks.
4304		4455
4305	=head2 COMPILER WARNINGS	4456	=head2 COMPILER WARNINGS
4306		4457
4307	Depending on your compiler and compiler settings, you might get no or a	4458	Depending on your compiler and compiler settings, you might get no or a
…		…
4318	maintainable.	4469	maintainable.
4319		4470
4320	And of course, some compiler warnings are just plain stupid, or simply	4471	And of course, some compiler warnings are just plain stupid, or simply
4321	wrong (because they don't actually warn about the condition their message	4472	wrong (because they don't actually warn about the condition their message
4322	seems to warn about). For example, certain older gcc versions had some	4473	seems to warn about). For example, certain older gcc versions had some
4323	warnings that resulted an extreme number of false positives. These have	4474	warnings that resulted in an extreme number of false positives. These have
4324	been fixed, but some people still insist on making code warn-free with	4475	been fixed, but some people still insist on making code warn-free with
4325	such buggy versions.	4476	such buggy versions.
4326		4477
4327	While libev is written to generate as few warnings as possible,	4478	While libev is written to generate as few warnings as possible,
4328	"warn-free" code is not a goal, and it is recommended not to build libev	4479	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4364	I suggest using suppression lists.	4515	I suggest using suppression lists.
4365		4516
4366		4517
4367	=head1 PORTABILITY NOTES	4518	=head1 PORTABILITY NOTES
4368		4519
		4520	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4521
		4522	GNU/Linux is the only common platform that supports 64 bit file/large file
		4523	interfaces but I<disables> them by default.
		4524
		4525	That means that libev compiled in the default environment doesn't support
		4526	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4527
		4528	Unfortunately, many programs try to work around this GNU/Linux issue
		4529	by enabling the large file API, which makes them incompatible with the
		4530	standard libev compiled for their system.
		4531
		4532	Likewise, libev cannot enable the large file API itself as this would
		4533	suddenly make it incompatible to the default compile time environment,
		4534	i.e. all programs not using special compile switches.
		4535
		4536	=head2 OS/X AND DARWIN BUGS
		4537
		4538	The whole thing is a bug if you ask me - basically any system interface
		4539	you touch is broken, whether it is locales, poll, kqueue or even the
		4540	OpenGL drivers.
		4541
		4542	=head3 C<kqueue> is buggy
		4543
		4544	The kqueue syscall is broken in all known versions - most versions support
		4545	only sockets, many support pipes.
		4546
		4547	Libev tries to work around this by not using C<kqueue> by default on this
		4548	rotten platform, but of course you can still ask for it when creating a
		4549	loop - embedding a socket-only kqueue loop into a select-based one is
		4550	probably going to work well.
		4551
		4552	=head3 C<poll> is buggy
		4553
		4554	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4555	implementation by something calling C<kqueue> internally around the 10.5.6
		4556	release, so now C<kqueue> I<and> C<poll> are broken.
		4557
		4558	Libev tries to work around this by not using C<poll> by default on
		4559	this rotten platform, but of course you can still ask for it when creating
		4560	a loop.
		4561
		4562	=head3 C<select> is buggy
		4563
		4564	All that's left is C<select>, and of course Apple found a way to fuck this
		4565	one up as well: On OS/X, C<select> actively limits the number of file
		4566	descriptors you can pass in to 1024 - your program suddenly crashes when
		4567	you use more.
		4568
		4569	There is an undocumented "workaround" for this - defining
		4570	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4571	work on OS/X.
		4572
		4573	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4574
		4575	=head3 C<errno> reentrancy
		4576
		4577	The default compile environment on Solaris is unfortunately so
		4578	thread-unsafe that you can't even use components/libraries compiled
		4579	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4580	defined by default. A valid, if stupid, implementation choice.
		4581
		4582	If you want to use libev in threaded environments you have to make sure
		4583	it's compiled with C<_REENTRANT> defined.
		4584
		4585	=head3 Event port backend
		4586
		4587	The scalable event interface for Solaris is called "event
		4588	ports". Unfortunately, this mechanism is very buggy in all major
		4589	releases. If you run into high CPU usage, your program freezes or you get
		4590	a large number of spurious wakeups, make sure you have all the relevant
		4591	and latest kernel patches applied. No, I don't know which ones, but there
		4592	are multiple ones to apply, and afterwards, event ports actually work
		4593	great.
		4594
		4595	If you can't get it to work, you can try running the program by setting
		4596	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4597	C<select> backends.
		4598
		4599	=head2 AIX POLL BUG
		4600
		4601	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4602	this by trying to avoid the poll backend altogether (i.e. it's not even
		4603	compiled in), which normally isn't a big problem as C<select> works fine
		4604	with large bitsets on AIX, and AIX is dead anyway.
		4605
4369	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4606	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4607
		4608	=head3 General issues
4370		4609
4371	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4610	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4372	requires, and its I/O model is fundamentally incompatible with the POSIX	4611	requires, and its I/O model is fundamentally incompatible with the POSIX
4373	model. Libev still offers limited functionality on this platform in	4612	model. Libev still offers limited functionality on this platform in
4374	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4613	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4375	descriptors. This only applies when using Win32 natively, not when using	4614	descriptors. This only applies when using Win32 natively, not when using
4376	e.g. cygwin.	4615	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4616	as every compielr comes with a slightly differently broken/incompatible
		4617	environment.
4377		4618
4378	Lifting these limitations would basically require the full	4619	Lifting these limitations would basically require the full
4379	re-implementation of the I/O system. If you are into these kinds of	4620	re-implementation of the I/O system. If you are into this kind of thing,
4380	things, then note that glib does exactly that for you in a very portable	4621	then note that glib does exactly that for you in a very portable way (note
4381	way (note also that glib is the slowest event library known to man).	4622	also that glib is the slowest event library known to man).
4382		4623
4383	There is no supported compilation method available on windows except	4624	There is no supported compilation method available on windows except
4384	embedding it into other applications.	4625	embedding it into other applications.
4385		4626
4386	Sensible signal handling is officially unsupported by Microsoft - libev	4627	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4414	you do I<not> compile the F<ev.c> or any other embedded source files!):	4655	you do I<not> compile the F<ev.c> or any other embedded source files!):
4415		4656
4416	#include "evwrap.h"	4657	#include "evwrap.h"
4417	#include "ev.c"	4658	#include "ev.c"
4418		4659
4419	=over 4
4420
4421	=item The winsocket select function	4660	=head3 The winsocket C<select> function
4422		4661
4423	The winsocket C<select> function doesn't follow POSIX in that it	4662	The winsocket C<select> function doesn't follow POSIX in that it
4424	requires socket I<handles> and not socket I<file descriptors> (it is	4663	requires socket I<handles> and not socket I<file descriptors> (it is
4425	also extremely buggy). This makes select very inefficient, and also	4664	also extremely buggy). This makes select very inefficient, and also
4426	requires a mapping from file descriptors to socket handles (the Microsoft	4665	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4435	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4674	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4436		4675
4437	Note that winsockets handling of fd sets is O(n), so you can easily get a	4676	Note that winsockets handling of fd sets is O(n), so you can easily get a
4438	complexity in the O(n²) range when using win32.	4677	complexity in the O(n²) range when using win32.
4439		4678
4440	=item Limited number of file descriptors	4679	=head3 Limited number of file descriptors
4441		4680
4442	Windows has numerous arbitrary (and low) limits on things.	4681	Windows has numerous arbitrary (and low) limits on things.
4443		4682
4444	Early versions of winsocket's select only supported waiting for a maximum	4683	Early versions of winsocket's select only supported waiting for a maximum
4445	of C<64> handles (probably owning to the fact that all windows kernels	4684	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4460	runtime libraries. This might get you to about C<512> or C<2048> sockets	4699	runtime libraries. This might get you to about C<512> or C<2048> sockets
4461	(depending on windows version and/or the phase of the moon). To get more,	4700	(depending on windows version and/or the phase of the moon). To get more,
4462	you need to wrap all I/O functions and provide your own fd management, but	4701	you need to wrap all I/O functions and provide your own fd management, but
4463	the cost of calling select (O(n²)) will likely make this unworkable.	4702	the cost of calling select (O(n²)) will likely make this unworkable.
4464		4703
4465	=back
4466
4467	=head2 PORTABILITY REQUIREMENTS	4704	=head2 PORTABILITY REQUIREMENTS
4468		4705
4469	In addition to a working ISO-C implementation and of course the	4706	In addition to a working ISO-C implementation and of course the
4470	backend-specific APIs, libev relies on a few additional extensions:	4707	backend-specific APIs, libev relies on a few additional extensions:
4471		4708
…		…
4509	watchers.	4746	watchers.
4510		4747
4511	=item C<double> must hold a time value in seconds with enough accuracy	4748	=item C<double> must hold a time value in seconds with enough accuracy
4512		4749
4513	The type C<double> is used to represent timestamps. It is required to	4750	The type C<double> is used to represent timestamps. It is required to
4514	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4751	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4515	enough for at least into the year 4000. This requirement is fulfilled by	4752	good enough for at least into the year 4000 with millisecond accuracy
		4753	(the design goal for libev). This requirement is overfulfilled by
4516	implementations implementing IEEE 754, which is basically all existing	4754	implementations using IEEE 754, which is basically all existing ones. With
4517	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4755	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4518	2200.
4519		4756
4520	=back	4757	=back
4521		4758
4522	If you know of other additional requirements drop me a note.	4759	If you know of other additional requirements drop me a note.
4523		4760
…		…
4591	involves iterating over all running async watchers or all signal numbers.	4828	involves iterating over all running async watchers or all signal numbers.
4592		4829
4593	=back	4830	=back
4594		4831
4595		4832
		4833	=head1 PORTING FROM LIBEV 3.X TO 4.X
		4834
		4835	The major version 4 introduced some minor incompatible changes to the API.
		4836
		4837	At the moment, the C<ev.h> header file tries to implement superficial
		4838	compatibility, so most programs should still compile. Those might be
		4839	removed in later versions of libev, so better update early than late.
		4840
		4841	=over 4
		4842
		4843	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4844
		4845	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4846
		4847	ev_loop_destroy (EV_DEFAULT);
		4848	ev_loop_fork (EV_DEFAULT);
		4849
		4850	=item function/symbol renames
		4851
		4852	A number of functions and symbols have been renamed:
		4853
		4854	ev_loop => ev_run
		4855	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4856	EVLOOP_ONESHOT => EVRUN_ONCE
		4857
		4858	ev_unloop => ev_break
		4859	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4860	EVUNLOOP_ONE => EVBREAK_ONE
		4861	EVUNLOOP_ALL => EVBREAK_ALL
		4862
		4863	EV_TIMEOUT => EV_TIMER
		4864
		4865	ev_loop_count => ev_iteration
		4866	ev_loop_depth => ev_depth
		4867	ev_loop_verify => ev_verify
		4868
		4869	Most functions working on C<struct ev_loop> objects don't have an
		4870	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4871	associated constants have been renamed to not collide with the C<struct
		4872	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4873	as all other watcher types. Note that C<ev_loop_fork> is still called
		4874	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
		4875	typedef.
		4876
		4877	=item C<EV_COMPAT3> backwards compatibility mechanism
		4878
		4879	The backward compatibility mechanism can be controlled by
		4880	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4881	section.
		4882
		4883	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
		4884
		4885	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
		4886	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
		4887	and work, but the library code will of course be larger.
		4888
		4889	=back
		4890
		4891
4596	=head1 GLOSSARY	4892	=head1 GLOSSARY
4597		4893
4598	=over 4	4894	=over 4
4599		4895
4600	=item active	4896	=item active
4601		4897
4602	A watcher is active as long as it has been started (has been attached to	4898	A watcher is active as long as it has been started and not yet stopped.
4603	an event loop) but not yet stopped (disassociated from the event loop).	4899	See L<WATCHER STATES> for details.
4604		4900
4605	=item application	4901	=item application
4606		4902
4607	In this document, an application is whatever is using libev.	4903	In this document, an application is whatever is using libev.
		4904
		4905	=item backend
		4906
		4907	The part of the code dealing with the operating system interfaces.
4608		4908
4609	=item callback	4909	=item callback
4610		4910
4611	The address of a function that is called when some event has been	4911	The address of a function that is called when some event has been
4612	detected. Callbacks are being passed the event loop, the watcher that	4912	detected. Callbacks are being passed the event loop, the watcher that
4613	received the event, and the actual event bitset.	4913	received the event, and the actual event bitset.
4614		4914
4615	=item callback invocation	4915	=item callback/watcher invocation
4616		4916
4617	The act of calling the callback associated with a watcher.	4917	The act of calling the callback associated with a watcher.
4618		4918
4619	=item event	4919	=item event
4620		4920
4621	A change of state of some external event, such as data now being available	4921	A change of state of some external event, such as data now being available
4622	for reading on a file descriptor, time having passed or simply not having	4922	for reading on a file descriptor, time having passed or simply not having
4623	any other events happening anymore.	4923	any other events happening anymore.
4624		4924
4625	In libev, events are represented as single bits (such as C<EV_READ> or	4925	In libev, events are represented as single bits (such as C<EV_READ> or
4626	C<EV_TIMEOUT>).	4926	C<EV_TIMER>).
4627		4927
4628	=item event library	4928	=item event library
4629		4929
4630	A software package implementing an event model and loop.	4930	A software package implementing an event model and loop.
4631		4931
…		…
4639	The model used to describe how an event loop handles and processes	4939	The model used to describe how an event loop handles and processes
4640	watchers and events.	4940	watchers and events.
4641		4941
4642	=item pending	4942	=item pending
4643		4943
4644	A watcher is pending as soon as the corresponding event has been detected,	4944	A watcher is pending as soon as the corresponding event has been
4645	and stops being pending as soon as the watcher will be invoked or its	4945	detected. See L<WATCHER STATES> for details.
4646	pending status is explicitly cleared by the application.
4647
4648	A watcher can be pending, but not active. Stopping a watcher also clears
4649	its pending status.
4650		4946
4651	=item real time	4947	=item real time
4652		4948
4653	The physical time that is observed. It is apparently strictly monotonic :)	4949	The physical time that is observed. It is apparently strictly monotonic :)
4654		4950
…		…
4661	=item watcher	4957	=item watcher
4662		4958
4663	A data structure that describes interest in certain events. Watchers need	4959	A data structure that describes interest in certain events. Watchers need
4664	to be started (attached to an event loop) before they can receive events.	4960	to be started (attached to an event loop) before they can receive events.
4665		4961
4666	=item watcher invocation
4667
4668	The act of calling the callback associated with a watcher.
4669
4670	=back	4962	=back
4671		4963
4672	=head1 AUTHOR	4964	=head1 AUTHOR
4673		4965
4674	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	4966	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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