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Comparing libev/ev.pod (file contents):
Revision 1.298 by sf-exg, Sat Jul 31 23:00:11 2010 UTC vs.
Revision 1.329 by root, Sun Oct 24 20:16:00 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
…		…
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 (in practise	129	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	somewhere near the beginning of 1970, details are complicated, don't	130	somewhere near the beginning of 1970, details are complicated, don't
131	ask). This type is called C<ev_tstamp>, which is what you should use	131	ask). This type is called C<ev_tstamp>, which is what you should use
132	too. It usually aliases to the C<double> type in C. When you need to do	132	too. It usually aliases to the C<double> type in C. When you need to do
133	any calculations on it, you should treat it as some floating point value.	133	any calculations on it, you should treat it as some floating point value.
134		134
…		…
165		165
166	=item ev_tstamp ev_time ()	166	=item ev_tstamp ev_time ()
167		167
168	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
169	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
170	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>.
171		172
172	=item ev_sleep (ev_tstamp interval)	173	=item ev_sleep (ev_tstamp interval)
173		174
174	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
175	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
…		…
192	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
193	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
194	not a problem.	195	not a problem.
195		196
196	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
197	version (note, however, that this will not detect ABI mismatches :).	198	version (note, however, that this will not detect other ABI mismatches,
		199	such as LFS or reentrancy).
198		200
199	assert (("libev version mismatch",	201	assert (("libev version mismatch",
200	ev_version_major () == EV_VERSION_MAJOR	202	ev_version_major () == EV_VERSION_MAJOR
201	&& ev_version_minor () >= EV_VERSION_MINOR));	203	&& ev_version_minor () >= EV_VERSION_MINOR));
202		204
…		…
213	assert (("sorry, no epoll, no sex",	215	assert (("sorry, no epoll, no sex",
214	ev_supported_backends () & EVBACKEND_EPOLL));	216	ev_supported_backends () & EVBACKEND_EPOLL));
215		217
216	=item unsigned int ev_recommended_backends ()	218	=item unsigned int ev_recommended_backends ()
217		219
218	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
219	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
220	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
221	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
222	(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
223	libev will probe for if you specify no backends explicitly.	226	probe for if you specify no backends explicitly.
224		227
225	=item unsigned int ev_embeddable_backends ()	228	=item unsigned int ev_embeddable_backends ()
226		229
227	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
228	is the theoretical, all-platform, value. To find which backends	231	value is platform-specific but can include backends not available on the
229	might be supported on the current system, you would need to look at	232	current system. To find which embeddable backends might be supported on
230	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	233	the current system, you would need to look at C<ev_embeddable_backends ()
231	recommended ones.	234	& ev_supported_backends ()>, likewise for recommended ones.
232		235
233	See the description of C<ev_embed> watchers for more info.	236	See the description of C<ev_embed> watchers for more info.
234		237
235	=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]
236		239
…		…
290	...	293	...
291	ev_set_syserr_cb (fatal_error);	294	ev_set_syserr_cb (fatal_error);
292		295
293	=back	296	=back
294		297
295	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	298	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
296		299
297	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
298	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
299	I<function>).	302	libev 3 had an C<ev_loop> function colliding with the struct name).
300		303
301	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
302	supports signals and child events, and dynamically created loops which do	305	supports signals and child events, and dynamically created event loops
303	not.	306	which do not.
304		307
305	=over 4	308	=over 4
306		309
307	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
308		311
309	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
310	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
311	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
312	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".
313		322
314	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
315	function.	324	function (or via the C<EV_DEFAULT> macro).
316		325
317	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
318	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
319	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).
320		330
321	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,
322	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
323	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
324	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
325	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	335	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
326	C<ev_default_init>.	336
		337	Example: This is the most typical usage.
		338
		339	if (!ev_default_loop (0))
		340	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		341
		342	Example: Restrict libev to the select and poll backends, and do not allow
		343	environment settings to be taken into account:
		344
		345	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
		346
		347	=item struct ev_loop *ev_loop_new (unsigned int flags)
		348
		349	This will create and initialise a new event loop object. If the loop
		350	could not be initialised, returns false.
		351
		352	Note that this function I<is> thread-safe, and one common way to use
		353	libev with threads is indeed to create one loop per thread, and using the
		354	default loop in the "main" or "initial" thread.
327		355
328	The flags argument can be used to specify special behaviour or specific	356	The flags argument can be used to specify special behaviour or specific
329	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	357	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
330		358
331	The following flags are supported:	359	The following flags are supported:
…		…
439	of course I<doesn't>, and epoll just loves to report events for totally	467	of course I<doesn't>, and epoll just loves to report events for totally
440	I<different> file descriptors (even already closed ones, so one cannot	468	I<different> file descriptors (even already closed ones, so one cannot
441	even remove them from the set) than registered in the set (especially	469	even remove them from the set) than registered in the set (especially
442	on SMP systems). Libev tries to counter these spurious notifications by	470	on SMP systems). Libev tries to counter these spurious notifications by
443	employing an additional generation counter and comparing that against the	471	employing an additional generation counter and comparing that against the
444	events to filter out spurious ones, recreating the set when required.	472	events to filter out spurious ones, recreating the set when required. Last
		473	not least, it also refuses to work with some file descriptors which work
		474	perfectly fine with C<select> (files, many character devices...).
445		475
446	While stopping, setting and starting an I/O watcher in the same iteration	476	While stopping, setting and starting an I/O watcher in the same iteration
447	will result in some caching, there is still a system call per such	477	will result in some caching, there is still a system call per such
448	incident (because the same I<file descriptor> could point to a different	478	incident (because the same I<file descriptor> could point to a different
449	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	479	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
547	If one or more of the backend flags are or'ed into the flags value,	577	If one or more of the backend flags are or'ed into the flags value,
548	then only these backends will be tried (in the reverse order as listed	578	then only these backends will be tried (in the reverse order as listed
549	here). If none are specified, all backends in C<ev_recommended_backends	579	here). If none are specified, all backends in C<ev_recommended_backends
550	()> will be tried.	580	()> will be tried.
551		581
552	Example: This is the most typical usage.
553
554	if (!ev_default_loop (0))
555	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
556
557	Example: Restrict libev to the select and poll backends, and do not allow
558	environment settings to be taken into account:
559
560	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
561
562	Example: Use whatever libev has to offer, but make sure that kqueue is
563	used if available (warning, breaks stuff, best use only with your own
564	private event loop and only if you know the OS supports your types of
565	fds):
566
567	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
568
569	=item struct ev_loop *ev_loop_new (unsigned int flags)
570
571	Similar to C<ev_default_loop>, but always creates a new event loop that is
572	always distinct from the default loop.
573
574	Note that this function I<is> thread-safe, and one common way to use
575	libev with threads is indeed to create one loop per thread, and using the
576	default loop in the "main" or "initial" thread.
577
578	Example: Try to create a event loop that uses epoll and nothing else.	582	Example: Try to create a event loop that uses epoll and nothing else.
579		583
580	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
581	if (!epoller)	585	if (!epoller)
582	fatal ("no epoll found here, maybe it hides under your chair");	586	fatal ("no epoll found here, maybe it hides under your chair");
583		587
		588	Example: Use whatever libev has to offer, but make sure that kqueue is
		589	used if available.
		590
		591	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
		592
584	=item ev_default_destroy ()	593	=item ev_loop_destroy (loop)
585		594
586	Destroys the default loop (frees all memory and kernel state etc.). None	595	Destroys an event loop object (frees all memory and kernel state
587	of the active event watchers will be stopped in the normal sense, so	596	etc.). None of the active event watchers will be stopped in the normal
588	e.g. C<ev_is_active> might still return true. It is your responsibility to	597	sense, so e.g. C<ev_is_active> might still return true. It is your
589	either stop all watchers cleanly yourself I<before> calling this function,	598	responsibility to either stop all watchers cleanly yourself I<before>
590	or cope with the fact afterwards (which is usually the easiest thing, you	599	calling this function, or cope with the fact afterwards (which is usually
591	can just ignore the watchers and/or C<free ()> them for example).	600	the easiest thing, you can just ignore the watchers and/or C<free ()> them
		601	for example).
592		602
593	Note that certain global state, such as signal state (and installed signal	603	Note that certain global state, such as signal state (and installed signal
594	handlers), will not be freed by this function, and related watchers (such	604	handlers), will not be freed by this function, and related watchers (such
595	as signal and child watchers) would need to be stopped manually.	605	as signal and child watchers) would need to be stopped manually.
596		606
597	In general it is not advisable to call this function except in the	607	This function is normally used on loop objects allocated by
598	rare occasion where you really need to free e.g. the signal handling	608	C<ev_loop_new>, but it can also be used on the default loop returned by
		609	C<ev_default_loop>, in which case it is not thread-safe.
		610
		611	Note that it is not advisable to call this function on the default loop
		612	except in the rare occasion where you really need to free it's resources.
599	pipe fds. If you need dynamically allocated loops it is better to use	613	If you need dynamically allocated loops it is better to use C<ev_loop_new>
600	C<ev_loop_new> and C<ev_loop_destroy>.	614	and C<ev_loop_destroy>.
601		615
602	=item ev_loop_destroy (loop)	616	=item ev_loop_fork (loop)
603		617
604	Like C<ev_default_destroy>, but destroys an event loop created by an
605	earlier call to C<ev_loop_new>.
606
607	=item ev_default_fork ()
608
609	This function sets a flag that causes subsequent C<ev_loop> iterations	618	This function sets a flag that causes subsequent C<ev_run> iterations to
610	to reinitialise the kernel state for backends that have one. Despite the	619	reinitialise the kernel state for backends that have one. Despite the
611	name, you can call it anytime, but it makes most sense after forking, in	620	name, you can call it anytime, but it makes most sense after forking, in
612	the child process (or both child and parent, but that again makes little	621	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
613	sense). You I<must> call it in the child before using any of the libev	622	child before resuming or calling C<ev_run>.
614	functions, and it will only take effect at the next C<ev_loop> iteration.
615		623
616	Again, you I<have> to call it on I<any> loop that you want to re-use after	624	Again, you I<have> to call it on I<any> loop that you want to re-use after
617	a fork, I<even if you do not plan to use the loop in the parent>. This is	625	a fork, I<even if you do not plan to use the loop in the parent>. This is
618	because some kernel interfaces *cough* I<kqueue> *cough* do funny things	626	because some kernel interfaces *cough* I<kqueue> *cough* do funny things
619	during fork.	627	during fork.
620		628
621	On the other hand, you only need to call this function in the child	629	On the other hand, you only need to call this function in the child
622	process if and only if you want to use the event loop in the child. If you	630	process if and only if you want to use the event loop in the child. If
623	just fork+exec or create a new loop in the child, you don't have to call	631	you just fork+exec or create a new loop in the child, you don't have to
624	it at all.	632	call it at all (in fact, C<epoll> is so badly broken that it makes a
		633	difference, but libev will usually detect this case on its own and do a
		634	costly reset of the backend).
625		635
626	The function itself is quite fast and it's usually not a problem to call	636	The function itself is quite fast and it's usually not a problem to call
627	it just in case after a fork. To make this easy, the function will fit in	637	it just in case after a fork.
628	quite nicely into a call to C<pthread_atfork>:
629		638
		639	Example: Automate calling C<ev_loop_fork> on the default loop when
		640	using pthreads.
		641
		642	static void
		643	post_fork_child (void)
		644	{
		645	ev_loop_fork (EV_DEFAULT);
		646	}
		647
		648	...
630	pthread_atfork (0, 0, ev_default_fork);	649	pthread_atfork (0, 0, post_fork_child);
631
632	=item ev_loop_fork (loop)
633
634	Like C<ev_default_fork>, but acts on an event loop created by
635	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
636	after fork that you want to re-use in the child, and how you keep track of
637	them is entirely your own problem.
638		650
639	=item int ev_is_default_loop (loop)	651	=item int ev_is_default_loop (loop)
640		652
641	Returns true when the given loop is, in fact, the default loop, and false	653	Returns true when the given loop is, in fact, the default loop, and false
642	otherwise.	654	otherwise.
643		655
644	=item unsigned int ev_iteration (loop)	656	=item unsigned int ev_iteration (loop)
645		657
646	Returns the current iteration count for the loop, which is identical to	658	Returns the current iteration count for the event loop, which is identical
647	the number of times libev did poll for new events. It starts at C<0> and	659	to the number of times libev did poll for new events. It starts at C<0>
648	happily wraps around with enough iterations.	660	and happily wraps around with enough iterations.
649		661
650	This value can sometimes be useful as a generation counter of sorts (it	662	This value can sometimes be useful as a generation counter of sorts (it
651	"ticks" the number of loop iterations), as it roughly corresponds with	663	"ticks" the number of loop iterations), as it roughly corresponds with
652	C<ev_prepare> and C<ev_check> calls - and is incremented between the	664	C<ev_prepare> and C<ev_check> calls - and is incremented between the
653	prepare and check phases.	665	prepare and check phases.
654		666
655	=item unsigned int ev_depth (loop)	667	=item unsigned int ev_depth (loop)
656		668
657	Returns the number of times C<ev_loop> was entered minus the number of	669	Returns the number of times C<ev_run> was entered minus the number of
658	times C<ev_loop> was exited, in other words, the recursion depth.	670	times C<ev_run> was exited, in other words, the recursion depth.
659		671
660	Outside C<ev_loop>, this number is zero. In a callback, this number is	672	Outside C<ev_run>, this number is zero. In a callback, this number is
661	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	673	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
662	in which case it is higher.	674	in which case it is higher.
663		675
664	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	676	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
665	etc.), doesn't count as "exit" - consider this as a hint to avoid such	677	etc.), doesn't count as "exit" - consider this as a hint to avoid such
666	ungentleman behaviour unless it's really convenient.	678	ungentleman-like behaviour unless it's really convenient.
667		679
668	=item unsigned int ev_backend (loop)	680	=item unsigned int ev_backend (loop)
669		681
670	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	682	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
671	use.	683	use.
…		…
680		692
681	=item ev_now_update (loop)	693	=item ev_now_update (loop)
682		694
683	Establishes the current time by querying the kernel, updating the time	695	Establishes the current time by querying the kernel, updating the time
684	returned by C<ev_now ()> in the progress. This is a costly operation and	696	returned by C<ev_now ()> in the progress. This is a costly operation and
685	is usually done automatically within C<ev_loop ()>.	697	is usually done automatically within C<ev_run ()>.
686		698
687	This function is rarely useful, but when some event callback runs for a	699	This function is rarely useful, but when some event callback runs for a
688	very long time without entering the event loop, updating libev's idea of	700	very long time without entering the event loop, updating libev's idea of
689	the current time is a good idea.	701	the current time is a good idea.
690		702
…		…
692		704
693	=item ev_suspend (loop)	705	=item ev_suspend (loop)
694		706
695	=item ev_resume (loop)	707	=item ev_resume (loop)
696		708
697	These two functions suspend and resume a loop, for use when the loop is	709	These two functions suspend and resume an event loop, for use when the
698	not used for a while and timeouts should not be processed.	710	loop is not used for a while and timeouts should not be processed.
699		711
700	A typical use case would be an interactive program such as a game: When	712	A typical use case would be an interactive program such as a game: When
701	the user presses C<^Z> to suspend the game and resumes it an hour later it	713	the user presses C<^Z> to suspend the game and resumes it an hour later it
702	would be best to handle timeouts as if no time had actually passed while	714	would be best to handle timeouts as if no time had actually passed while
703	the program was suspended. This can be achieved by calling C<ev_suspend>	715	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
714	without a previous call to C<ev_suspend>.	726	without a previous call to C<ev_suspend>.
715		727
716	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	728	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
717	event loop time (see C<ev_now_update>).	729	event loop time (see C<ev_now_update>).
718		730
719	=item ev_loop (loop, int flags)	731	=item ev_run (loop, int flags)
720		732
721	Finally, this is it, the event handler. This function usually is called	733	Finally, this is it, the event handler. This function usually is called
722	after you have initialised all your watchers and you want to start	734	after you have initialised all your watchers and you want to start
723	handling events.	735	handling events. It will ask the operating system for any new events, call
		736	the watcher callbacks, an then repeat the whole process indefinitely: This
		737	is why event loops are called I<loops>.
724		738
725	If the flags argument is specified as C<0>, it will not return until	739	If the flags argument is specified as C<0>, it will keep handling events
726	either no event watchers are active anymore or C<ev_unloop> was called.	740	until either no event watchers are active anymore or C<ev_break> was
		741	called.
727		742
728	Please note that an explicit C<ev_unloop> is usually better than	743	Please note that an explicit C<ev_break> is usually better than
729	relying on all watchers to be stopped when deciding when a program has	744	relying on all watchers to be stopped when deciding when a program has
730	finished (especially in interactive programs), but having a program	745	finished (especially in interactive programs), but having a program
731	that automatically loops as long as it has to and no longer by virtue	746	that automatically loops as long as it has to and no longer by virtue
732	of relying on its watchers stopping correctly, that is truly a thing of	747	of relying on its watchers stopping correctly, that is truly a thing of
733	beauty.	748	beauty.
734		749
735	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	750	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
736	those events and any already outstanding ones, but will not block your	751	those events and any already outstanding ones, but will not wait and
737	process in case there are no events and will return after one iteration of	752	block your process in case there are no events and will return after one
738	the loop.	753	iteration of the loop. This is sometimes useful to poll and handle new
		754	events while doing lengthy calculations, to keep the program responsive.
739		755
740	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	756	A flags value of C<EVRUN_ONCE> will look for new events (waiting if
741	necessary) and will handle those and any already outstanding ones. It	757	necessary) and will handle those and any already outstanding ones. It
742	will block your process until at least one new event arrives (which could	758	will block your process until at least one new event arrives (which could
743	be an event internal to libev itself, so there is no guarantee that a	759	be an event internal to libev itself, so there is no guarantee that a
744	user-registered callback will be called), and will return after one	760	user-registered callback will be called), and will return after one
745	iteration of the loop.	761	iteration of the loop.
746		762
747	This is useful if you are waiting for some external event in conjunction	763	This is useful if you are waiting for some external event in conjunction
748	with something not expressible using other libev watchers (i.e. "roll your	764	with something not expressible using other libev watchers (i.e. "roll your
749	own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is	765	own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
750	usually a better approach for this kind of thing.	766	usually a better approach for this kind of thing.
751		767
752	Here are the gory details of what C<ev_loop> does:	768	Here are the gory details of what C<ev_run> does:
753		769
		770	- Increment loop depth.
		771	- Reset the ev_break status.
754	- Before the first iteration, call any pending watchers.	772	- Before the first iteration, call any pending watchers.
		773	LOOP:
755	* If EVFLAG_FORKCHECK was used, check for a fork.	774	- If EVFLAG_FORKCHECK was used, check for a fork.
756	- If a fork was detected (by any means), queue and call all fork watchers.	775	- If a fork was detected (by any means), queue and call all fork watchers.
757	- Queue and call all prepare watchers.	776	- Queue and call all prepare watchers.
		777	- If ev_break was called, goto FINISH.
758	- If we have been forked, detach and recreate the kernel state	778	- If we have been forked, detach and recreate the kernel state
759	as to not disturb the other process.	779	as to not disturb the other process.
760	- Update the kernel state with all outstanding changes.	780	- Update the kernel state with all outstanding changes.
761	- Update the "event loop time" (ev_now ()).	781	- Update the "event loop time" (ev_now ()).
762	- Calculate for how long to sleep or block, if at all	782	- Calculate for how long to sleep or block, if at all
763	(active idle watchers, EVLOOP_NONBLOCK or not having	783	(active idle watchers, EVRUN_NOWAIT or not having
764	any active watchers at all will result in not sleeping).	784	any active watchers at all will result in not sleeping).
765	- Sleep if the I/O and timer collect interval say so.	785	- Sleep if the I/O and timer collect interval say so.
		786	- Increment loop iteration counter.
766	- Block the process, waiting for any events.	787	- Block the process, waiting for any events.
767	- Queue all outstanding I/O (fd) events.	788	- Queue all outstanding I/O (fd) events.
768	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	789	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
769	- Queue all expired timers.	790	- Queue all expired timers.
770	- Queue all expired periodics.	791	- Queue all expired periodics.
771	- Unless any events are pending now, queue all idle watchers.	792	- Queue all idle watchers with priority higher than that of pending events.
772	- Queue all check watchers.	793	- Queue all check watchers.
773	- Call all queued watchers in reverse order (i.e. check watchers first).	794	- Call all queued watchers in reverse order (i.e. check watchers first).
774	Signals and child watchers are implemented as I/O watchers, and will	795	Signals and child watchers are implemented as I/O watchers, and will
775	be handled here by queueing them when their watcher gets executed.	796	be handled here by queueing them when their watcher gets executed.
776	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	797	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
777	were used, or there are no active watchers, return, otherwise	798	were used, or there are no active watchers, goto FINISH, otherwise
778	continue with step *.	799	continue with step LOOP.
		800	FINISH:
		801	- Reset the ev_break status iff it was EVBREAK_ONE.
		802	- Decrement the loop depth.
		803	- Return.
779		804
780	Example: Queue some jobs and then loop until no events are outstanding	805	Example: Queue some jobs and then loop until no events are outstanding
781	anymore.	806	anymore.
782		807
783	... queue jobs here, make sure they register event watchers as long	808	... queue jobs here, make sure they register event watchers as long
784	... as they still have work to do (even an idle watcher will do..)	809	... as they still have work to do (even an idle watcher will do..)
785	ev_loop (my_loop, 0);	810	ev_run (my_loop, 0);
786	... jobs done or somebody called unloop. yeah!	811	... jobs done or somebody called unloop. yeah!
787		812
788	=item ev_unloop (loop, how)	813	=item ev_break (loop, how)
789		814
790	Can be used to make a call to C<ev_loop> return early (but only after it	815	Can be used to make a call to C<ev_run> return early (but only after it
791	has processed all outstanding events). The C<how> argument must be either	816	has processed all outstanding events). The C<how> argument must be either
792	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or	817	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
793	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.	818	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
794		819
795	This "unloop state" will be cleared when entering C<ev_loop> again.	820	This "unloop state" will be cleared when entering C<ev_run> again.
796		821
797	It is safe to call C<ev_unloop> from outside any C<ev_loop> calls.	822	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##
798		823
799	=item ev_ref (loop)	824	=item ev_ref (loop)
800		825
801	=item ev_unref (loop)	826	=item ev_unref (loop)
802		827
803	Ref/unref can be used to add or remove a reference count on the event	828	Ref/unref can be used to add or remove a reference count on the event
804	loop: Every watcher keeps one reference, and as long as the reference	829	loop: Every watcher keeps one reference, and as long as the reference
805	count is nonzero, C<ev_loop> will not return on its own.	830	count is nonzero, C<ev_run> will not return on its own.
806		831
807	This is useful when you have a watcher that you never intend to	832	This is useful when you have a watcher that you never intend to
808	unregister, but that nevertheless should not keep C<ev_loop> from	833	unregister, but that nevertheless should not keep C<ev_run> from
809	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>	834	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
810	before stopping it.	835	before stopping it.
811		836
812	As an example, libev itself uses this for its internal signal pipe: It	837	As an example, libev itself uses this for its internal signal pipe: It
813	is not visible to the libev user and should not keep C<ev_loop> from	838	is not visible to the libev user and should not keep C<ev_run> from
814	exiting if no event watchers registered by it are active. It is also an	839	exiting if no event watchers registered by it are active. It is also an
815	excellent way to do this for generic recurring timers or from within	840	excellent way to do this for generic recurring timers or from within
816	third-party libraries. Just remember to I<unref after start> and I<ref	841	third-party libraries. Just remember to I<unref after start> and I<ref
817	before stop> (but only if the watcher wasn't active before, or was active	842	before stop> (but only if the watcher wasn't active before, or was active
818	before, respectively. Note also that libev might stop watchers itself	843	before, respectively. Note also that libev might stop watchers itself
819	(e.g. non-repeating timers) in which case you have to C<ev_ref>	844	(e.g. non-repeating timers) in which case you have to C<ev_ref>
820	in the callback).	845	in the callback).
821		846
822	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	847	Example: Create a signal watcher, but keep it from keeping C<ev_run>
823	running when nothing else is active.	848	running when nothing else is active.
824		849
825	ev_signal exitsig;	850	ev_signal exitsig;
826	ev_signal_init (&exitsig, sig_cb, SIGINT);	851	ev_signal_init (&exitsig, sig_cb, SIGINT);
827	ev_signal_start (loop, &exitsig);	852	ev_signal_start (loop, &exitsig);
…		…
890	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	915	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
891		916
892	=item ev_invoke_pending (loop)	917	=item ev_invoke_pending (loop)
893		918
894	This call will simply invoke all pending watchers while resetting their	919	This call will simply invoke all pending watchers while resetting their
895	pending state. Normally, C<ev_loop> does this automatically when required,	920	pending state. Normally, C<ev_run> does this automatically when required,
896	but when overriding the invoke callback this call comes handy.	921	but when overriding the invoke callback this call comes handy. This
		922	function can be invoked from a watcher - this can be useful for example
		923	when you want to do some lengthy calculation and want to pass further
		924	event handling to another thread (you still have to make sure only one
		925	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
897		926
898	=item int ev_pending_count (loop)	927	=item int ev_pending_count (loop)
899		928
900	Returns the number of pending watchers - zero indicates that no watchers	929	Returns the number of pending watchers - zero indicates that no watchers
901	are pending.	930	are pending.
902		931
903	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	932	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
904		933
905	This overrides the invoke pending functionality of the loop: Instead of	934	This overrides the invoke pending functionality of the loop: Instead of
906	invoking all pending watchers when there are any, C<ev_loop> will call	935	invoking all pending watchers when there are any, C<ev_run> will call
907	this callback instead. This is useful, for example, when you want to	936	this callback instead. This is useful, for example, when you want to
908	invoke the actual watchers inside another context (another thread etc.).	937	invoke the actual watchers inside another context (another thread etc.).
909		938
910	If you want to reset the callback, use C<ev_invoke_pending> as new	939	If you want to reset the callback, use C<ev_invoke_pending> as new
911	callback.	940	callback.
…		…
914		943
915	Sometimes you want to share the same loop between multiple threads. This	944	Sometimes you want to share the same loop between multiple threads. This
916	can be done relatively simply by putting mutex_lock/unlock calls around	945	can be done relatively simply by putting mutex_lock/unlock calls around
917	each call to a libev function.	946	each call to a libev function.
918		947
919	However, C<ev_loop> can run an indefinite time, so it is not feasible to	948	However, C<ev_run> can run an indefinite time, so it is not feasible
920	wait for it to return. One way around this is to wake up the loop via	949	to wait for it to return. One way around this is to wake up the event
921	C<ev_unloop> and C<av_async_send>, another way is to set these I<release>	950	loop via C<ev_break> and C<av_async_send>, another way is to set these
922	and I<acquire> callbacks on the loop.	951	I<release> and I<acquire> callbacks on the loop.
923		952
924	When set, then C<release> will be called just before the thread is	953	When set, then C<release> will be called just before the thread is
925	suspended waiting for new events, and C<acquire> is called just	954	suspended waiting for new events, and C<acquire> is called just
926	afterwards.	955	afterwards.
927		956
…		…
930		959
931	While event loop modifications are allowed between invocations of	960	While event loop modifications are allowed between invocations of
932	C<release> and C<acquire> (that's their only purpose after all), no	961	C<release> and C<acquire> (that's their only purpose after all), no
933	modifications done will affect the event loop, i.e. adding watchers will	962	modifications done will affect the event loop, i.e. adding watchers will
934	have no effect on the set of file descriptors being watched, or the time	963	have no effect on the set of file descriptors being watched, or the time
935	waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it	964	waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
936	to take note of any changes you made.	965	to take note of any changes you made.
937		966
938	In theory, threads executing C<ev_loop> will be async-cancel safe between	967	In theory, threads executing C<ev_run> will be async-cancel safe between
939	invocations of C<release> and C<acquire>.	968	invocations of C<release> and C<acquire>.
940		969
941	See also the locking example in the C<THREADS> section later in this	970	See also the locking example in the C<THREADS> section later in this
942	document.	971	document.
943		972
…		…
952	These two functions can be used to associate arbitrary data with a loop,	981	These two functions can be used to associate arbitrary data with a loop,
953	and are intended solely for the C<invoke_pending_cb>, C<release> and	982	and are intended solely for the C<invoke_pending_cb>, C<release> and
954	C<acquire> callbacks described above, but of course can be (ab-)used for	983	C<acquire> callbacks described above, but of course can be (ab-)used for
955	any other purpose as well.	984	any other purpose as well.
956		985
957	=item ev_loop_verify (loop)	986	=item ev_verify (loop)
958		987
959	This function only does something when C<EV_VERIFY> support has been	988	This function only does something when C<EV_VERIFY> support has been
960	compiled in, which is the default for non-minimal builds. It tries to go	989	compiled in, which is the default for non-minimal builds. It tries to go
961	through all internal structures and checks them for validity. If anything	990	through all internal structures and checks them for validity. If anything
962	is found to be inconsistent, it will print an error message to standard	991	is found to be inconsistent, it will print an error message to standard
…		…
973		1002
974	In the following description, uppercase C<TYPE> in names stands for the	1003	In the following description, uppercase C<TYPE> in names stands for the
975	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1004	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
976	watchers and C<ev_io_start> for I/O watchers.	1005	watchers and C<ev_io_start> for I/O watchers.
977		1006
978	A watcher is a structure that you create and register to record your	1007	A watcher is an opaque structure that you allocate and register to record
979	interest in some event. For instance, if you want to wait for STDIN to	1008	your interest in some event. To make a concrete example, imagine you want
980	become readable, you would create an C<ev_io> watcher for that:	1009	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1010	for that:
981		1011
982	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)	1012	static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
983	{	1013	{
984	ev_io_stop (w);	1014	ev_io_stop (w);
985	ev_unloop (loop, EVUNLOOP_ALL);	1015	ev_break (loop, EVBREAK_ALL);
986	}	1016	}
987		1017
988	struct ev_loop *loop = ev_default_loop (0);	1018	struct ev_loop *loop = ev_default_loop (0);
989		1019
990	ev_io stdin_watcher;	1020	ev_io stdin_watcher;
991		1021
992	ev_init (&stdin_watcher, my_cb);	1022	ev_init (&stdin_watcher, my_cb);
993	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1023	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
994	ev_io_start (loop, &stdin_watcher);	1024	ev_io_start (loop, &stdin_watcher);
995		1025
996	ev_loop (loop, 0);	1026	ev_run (loop, 0);
997		1027
998	As you can see, you are responsible for allocating the memory for your	1028	As you can see, you are responsible for allocating the memory for your
999	watcher structures (and it is I<usually> a bad idea to do this on the	1029	watcher structures (and it is I<usually> a bad idea to do this on the
1000	stack).	1030	stack).
1001		1031
1002	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1032	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1003	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1033	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1004		1034
1005	Each watcher structure must be initialised by a call to C<ev_init	1035	Each watcher structure must be initialised by a call to C<ev_init (watcher
1006	(watcher *, callback)>, which expects a callback to be provided. This	1036	*, callback)>, which expects a callback to be provided. This callback is
1007	callback gets invoked each time the event occurs (or, in the case of I/O	1037	invoked each time the event occurs (or, in the case of I/O watchers, each
1008	watchers, each time the event loop detects that the file descriptor given	1038	time the event loop detects that the file descriptor given is readable
1009	is readable and/or writable).	1039	and/or writable).
1010		1040
1011	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1041	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1012	macro to configure it, with arguments specific to the watcher type. There	1042	macro to configure it, with arguments specific to the watcher type. There
1013	is also a macro to combine initialisation and setting in one call: C<<	1043	is also a macro to combine initialisation and setting in one call: C<<
1014	ev_TYPE_init (watcher *, callback, ...) >>.	1044	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1065		1095
1066	=item C<EV_PREPARE>	1096	=item C<EV_PREPARE>
1067		1097
1068	=item C<EV_CHECK>	1098	=item C<EV_CHECK>
1069		1099
1070	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1100	All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1071	to gather new events, and all C<ev_check> watchers are invoked just after	1101	to gather new events, and all C<ev_check> watchers are invoked just after
1072	C<ev_loop> has gathered them, but before it invokes any callbacks for any	1102	C<ev_run> has gathered them, but before it invokes any callbacks for any
1073	received events. Callbacks of both watcher types can start and stop as	1103	received events. Callbacks of both watcher types can start and stop as
1074	many watchers as they want, and all of them will be taken into account	1104	many watchers as they want, and all of them will be taken into account
1075	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	1105	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1076	C<ev_loop> from blocking).	1106	C<ev_run> from blocking).
1077		1107
1078	=item C<EV_EMBED>	1108	=item C<EV_EMBED>
1079		1109
1080	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1110	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1081		1111
1082	=item C<EV_FORK>	1112	=item C<EV_FORK>
1083		1113
1084	The event loop has been resumed in the child process after fork (see	1114	The event loop has been resumed in the child process after fork (see
1085	C<ev_fork>).	1115	C<ev_fork>).
		1116
		1117	=item C<EV_CLEANUP>
		1118
		1119	The event loop is abotu to be destroyed (see C<ev_cleanup>).
1086		1120
1087	=item C<EV_ASYNC>	1121	=item C<EV_ASYNC>
1088		1122
1089	The given async watcher has been asynchronously notified (see C<ev_async>).	1123	The given async watcher has been asynchronously notified (see C<ev_async>).
1090		1124
…		…
1109	example it might indicate that a fd is readable or writable, and if your	1143	example it might indicate that a fd is readable or writable, and if your
1110	callbacks is well-written it can just attempt the operation and cope with	1144	callbacks is well-written it can just attempt the operation and cope with
1111	the error from read() or write(). This will not work in multi-threaded	1145	the error from read() or write(). This will not work in multi-threaded
1112	programs, though, as the fd could already be closed and reused for another	1146	programs, though, as the fd could already be closed and reused for another
1113	thing, so beware.	1147	thing, so beware.
		1148
		1149	=back
		1150
		1151	=head2 WATCHER STATES
		1152
		1153	There are various watcher states mentioned throughout this manual -
		1154	active, pending and so on. In this section these states and the rules to
		1155	transition between them will be described in more detail - and while these
		1156	rules might look complicated, they usually do "the right thing".
		1157
		1158	=over 4
		1159
		1160	=item initialiased
		1161
		1162	Before a watcher can be registered with the event looop it has to be
		1163	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1164	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1165
		1166	In this state it is simply some block of memory that is suitable for use
		1167	in an event loop. It can be moved around, freed, reused etc. at will.
		1168
		1169	=item started/running/active
		1170
		1171	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1172	property of the event loop, and is actively waiting for events. While in
		1173	this state it cannot be accessed (except in a few documented ways), moved,
		1174	freed or anything else - the only legal thing is to keep a pointer to it,
		1175	and call libev functions on it that are documented to work on active watchers.
		1176
		1177	=item pending
		1178
		1179	If a watcher is active and libev determines that an event it is interested
		1180	in has occurred (such as a timer expiring), it will become pending. It will
		1181	stay in this pending state until either it is stopped or its callback is
		1182	about to be invoked, so it is not normally pending inside the watcher
		1183	callback.
		1184
		1185	The watcher might or might not be active while it is pending (for example,
		1186	an expired non-repeating timer can be pending but no longer active). If it
		1187	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1188	but it is still property of the event loop at this time, so cannot be
		1189	moved, freed or reused. And if it is active the rules described in the
		1190	previous item still apply.
		1191
		1192	It is also possible to feed an event on a watcher that is not active (e.g.
		1193	via C<ev_feed_event>), in which case it becomes pending without being
		1194	active.
		1195
		1196	=item stopped
		1197
		1198	A watcher can be stopped implicitly by libev (in which case it might still
		1199	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1200	latter will clear any pending state the watcher might be in, regardless
		1201	of whether it was active or not, so stopping a watcher explicitly before
		1202	freeing it is often a good idea.
		1203
		1204	While stopped (and not pending) the watcher is essentially in the
		1205	initialised state, that is it can be reused, moved, modified in any way
		1206	you wish.
1114		1207
1115	=back	1208	=back
1116		1209
1117	=head2 GENERIC WATCHER FUNCTIONS	1210	=head2 GENERIC WATCHER FUNCTIONS
1118		1211
…		…
1622	...	1715	...
1623	struct ev_loop *loop = ev_default_init (0);	1716	struct ev_loop *loop = ev_default_init (0);
1624	ev_io stdin_readable;	1717	ev_io stdin_readable;
1625	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1718	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1626	ev_io_start (loop, &stdin_readable);	1719	ev_io_start (loop, &stdin_readable);
1627	ev_loop (loop, 0);	1720	ev_run (loop, 0);
1628		1721
1629		1722
1630	=head2 C<ev_timer> - relative and optionally repeating timeouts	1723	=head2 C<ev_timer> - relative and optionally repeating timeouts
1631		1724
1632	Timer watchers are simple relative timers that generate an event after a	1725	Timer watchers are simple relative timers that generate an event after a
…		…
1641	The callback is guaranteed to be invoked only I<after> its timeout has	1734	The callback is guaranteed to be invoked only I<after> its timeout has
1642	passed (not I<at>, so on systems with very low-resolution clocks this	1735	passed (not I<at>, so on systems with very low-resolution clocks this
1643	might introduce a small delay). If multiple timers become ready during the	1736	might introduce a small delay). If multiple timers become ready during the
1644	same loop iteration then the ones with earlier time-out values are invoked	1737	same loop iteration then the ones with earlier time-out values are invoked
1645	before ones of the same priority with later time-out values (but this is	1738	before ones of the same priority with later time-out values (but this is
1646	no longer true when a callback calls C<ev_loop> recursively).	1739	no longer true when a callback calls C<ev_run> recursively).
1647		1740
1648	=head3 Be smart about timeouts	1741	=head3 Be smart about timeouts
1649		1742
1650	Many real-world problems involve some kind of timeout, usually for error	1743	Many real-world problems involve some kind of timeout, usually for error
1651	recovery. A typical example is an HTTP request - if the other side hangs,	1744	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1822		1915
1823	=head3 The special problem of time updates	1916	=head3 The special problem of time updates
1824		1917
1825	Establishing the current time is a costly operation (it usually takes at	1918	Establishing the current time is a costly operation (it usually takes at
1826	least two system calls): EV therefore updates its idea of the current	1919	least two system calls): EV therefore updates its idea of the current
1827	time only before and after C<ev_loop> collects new events, which causes a	1920	time only before and after C<ev_run> collects new events, which causes a
1828	growing difference between C<ev_now ()> and C<ev_time ()> when handling	1921	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1829	lots of events in one iteration.	1922	lots of events in one iteration.
1830		1923
1831	The relative timeouts are calculated relative to the C<ev_now ()>	1924	The relative timeouts are calculated relative to the C<ev_now ()>
1832	time. This is usually the right thing as this timestamp refers to the time	1925	time. This is usually the right thing as this timestamp refers to the time
…		…
1949	}	2042	}
1950		2043
1951	ev_timer mytimer;	2044	ev_timer mytimer;
1952	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2045	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1953	ev_timer_again (&mytimer); /* start timer */	2046	ev_timer_again (&mytimer); /* start timer */
1954	ev_loop (loop, 0);	2047	ev_run (loop, 0);
1955		2048
1956	// and in some piece of code that gets executed on any "activity":	2049	// and in some piece of code that gets executed on any "activity":
1957	// reset the timeout to start ticking again at 10 seconds	2050	// reset the timeout to start ticking again at 10 seconds
1958	ev_timer_again (&mytimer);	2051	ev_timer_again (&mytimer);
1959		2052
…		…
1985		2078
1986	As with timers, the callback is guaranteed to be invoked only when the	2079	As with timers, the callback is guaranteed to be invoked only when the
1987	point in time where it is supposed to trigger has passed. If multiple	2080	point in time where it is supposed to trigger has passed. If multiple
1988	timers become ready during the same loop iteration then the ones with	2081	timers become ready during the same loop iteration then the ones with
1989	earlier time-out values are invoked before ones with later time-out values	2082	earlier time-out values are invoked before ones with later time-out values
1990	(but this is no longer true when a callback calls C<ev_loop> recursively).	2083	(but this is no longer true when a callback calls C<ev_run> recursively).
1991		2084
1992	=head3 Watcher-Specific Functions and Data Members	2085	=head3 Watcher-Specific Functions and Data Members
1993		2086
1994	=over 4	2087	=over 4
1995		2088
…		…
2123	Example: Call a callback every hour, or, more precisely, whenever the	2216	Example: Call a callback every hour, or, more precisely, whenever the
2124	system time is divisible by 3600. The callback invocation times have	2217	system time is divisible by 3600. The callback invocation times have
2125	potentially a lot of jitter, but good long-term stability.	2218	potentially a lot of jitter, but good long-term stability.
2126		2219
2127	static void	2220	static void
2128	clock_cb (struct ev_loop *loop, ev_io *w, int revents)	2221	clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
2129	{	2222	{
2130	... its now a full hour (UTC, or TAI or whatever your clock follows)	2223	... its now a full hour (UTC, or TAI or whatever your clock follows)
2131	}	2224	}
2132		2225
2133	ev_periodic hourly_tick;	2226	ev_periodic hourly_tick;
…		…
2233	Example: Try to exit cleanly on SIGINT.	2326	Example: Try to exit cleanly on SIGINT.
2234		2327
2235	static void	2328	static void
2236	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)	2329	sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2237	{	2330	{
2238	ev_unloop (loop, EVUNLOOP_ALL);	2331	ev_break (loop, EVBREAK_ALL);
2239	}	2332	}
2240		2333
2241	ev_signal signal_watcher;	2334	ev_signal signal_watcher;
2242	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2335	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2243	ev_signal_start (loop, &signal_watcher);	2336	ev_signal_start (loop, &signal_watcher);
…		…
2629		2722
2630	Prepare and check watchers are usually (but not always) used in pairs:	2723	Prepare and check watchers are usually (but not always) used in pairs:
2631	prepare watchers get invoked before the process blocks and check watchers	2724	prepare watchers get invoked before the process blocks and check watchers
2632	afterwards.	2725	afterwards.
2633		2726
2634	You I<must not> call C<ev_loop> or similar functions that enter	2727	You I<must not> call C<ev_run> or similar functions that enter
2635	the current event loop from either C<ev_prepare> or C<ev_check>	2728	the current event loop from either C<ev_prepare> or C<ev_check>
2636	watchers. Other loops than the current one are fine, however. The	2729	watchers. Other loops than the current one are fine, however. The
2637	rationale behind this is that you do not need to check for recursion in	2730	rationale behind this is that you do not need to check for recursion in
2638	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,	2731	those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2639	C<ev_check> so if you have one watcher of each kind they will always be	2732	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2807		2900
2808	if (timeout >= 0)	2901	if (timeout >= 0)
2809	// create/start timer	2902	// create/start timer
2810		2903
2811	// poll	2904	// poll
2812	ev_loop (EV_A_ 0);	2905	ev_run (EV_A_ 0);
2813		2906
2814	// stop timer again	2907	// stop timer again
2815	if (timeout >= 0)	2908	if (timeout >= 0)
2816	ev_timer_stop (EV_A_ &to);	2909	ev_timer_stop (EV_A_ &to);
2817		2910
…		…
2895	if you do not want that, you need to temporarily stop the embed watcher).	2988	if you do not want that, you need to temporarily stop the embed watcher).
2896		2989
2897	=item ev_embed_sweep (loop, ev_embed *)	2990	=item ev_embed_sweep (loop, ev_embed *)
2898		2991
2899	Make a single, non-blocking sweep over the embedded loop. This works	2992	Make a single, non-blocking sweep over the embedded loop. This works
2900	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2993	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2901	appropriate way for embedded loops.	2994	appropriate way for embedded loops.
2902		2995
2903	=item struct ev_loop *other [read-only]	2996	=item struct ev_loop *other [read-only]
2904		2997
2905	The embedded event loop.	2998	The embedded event loop.
…		…
2965	C<ev_default_fork> cheats and calls it in the wrong process, the fork	3058	C<ev_default_fork> cheats and calls it in the wrong process, the fork
2966	handlers will be invoked, too, of course.	3059	handlers will be invoked, too, of course.
2967		3060
2968	=head3 The special problem of life after fork - how is it possible?	3061	=head3 The special problem of life after fork - how is it possible?
2969		3062
2970	Most uses of C<fork()> consist of forking, then some simple calls to ste	3063	Most uses of C<fork()> consist of forking, then some simple calls to set
2971	up/change the process environment, followed by a call to C<exec()>. This	3064	up/change the process environment, followed by a call to C<exec()>. This
2972	sequence should be handled by libev without any problems.	3065	sequence should be handled by libev without any problems.
2973		3066
2974	This changes when the application actually wants to do event handling	3067	This changes when the application actually wants to do event handling
2975	in the child, or both parent in child, in effect "continuing" after the	3068	in the child, or both parent in child, in effect "continuing" after the
…		…
2991	disadvantage of having to use multiple event loops (which do not support	3084	disadvantage of having to use multiple event loops (which do not support
2992	signal watchers).	3085	signal watchers).
2993		3086
2994	When this is not possible, or you want to use the default loop for	3087	When this is not possible, or you want to use the default loop for
2995	other reasons, then in the process that wants to start "fresh", call	3088	other reasons, then in the process that wants to start "fresh", call
2996	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3089	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
2997	the default loop will "orphan" (not stop) all registered watchers, so you	3090	Destroying the default loop will "orphan" (not stop) all registered
2998	have to be careful not to execute code that modifies those watchers. Note	3091	watchers, so you have to be careful not to execute code that modifies
2999	also that in that case, you have to re-register any signal watchers.	3092	those watchers. Note also that in that case, you have to re-register any
		3093	signal watchers.
3000		3094
3001	=head3 Watcher-Specific Functions and Data Members	3095	=head3 Watcher-Specific Functions and Data Members
3002		3096
3003	=over 4	3097	=over 4
3004		3098
3005	=item ev_fork_init (ev_signal *, callback)	3099	=item ev_fork_init (ev_fork *, callback)
3006		3100
3007	Initialises and configures the fork watcher - it has no parameters of any	3101	Initialises and configures the fork watcher - it has no parameters of any
3008	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,	3102	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3009	believe me.	3103	really.
3010		3104
3011	=back	3105	=back
3012		3106
3013		3107
		3108	=head2 C<ev_cleanup> - even the best things end
		3109
		3110	Cleanup watchers are called just before the event loop is being destroyed
		3111	by a call to C<ev_loop_destroy>.
		3112
		3113	While there is no guarantee that the event loop gets destroyed, cleanup
		3114	watchers provide a convenient method to install cleanup hooks for your
		3115	program, worker threads and so on - you just to make sure to destroy the
		3116	loop when you want them to be invoked.
		3117
		3118	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3119	all other watchers, they do not keep a reference to the event loop (which
		3120	makes a lot of sense if you think about it). Like all other watchers, you
		3121	can call libev functions in the callback, except C<ev_cleanup_start>.
		3122
		3123	=head3 Watcher-Specific Functions and Data Members
		3124
		3125	=over 4
		3126
		3127	=item ev_cleanup_init (ev_cleanup *, callback)
		3128
		3129	Initialises and configures the cleanup watcher - it has no parameters of
		3130	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3131	pointless, I assure you.
		3132
		3133	=back
		3134
		3135	Example: Register an atexit handler to destroy the default loop, so any
		3136	cleanup functions are called.
		3137
		3138	static void
		3139	program_exits (void)
		3140	{
		3141	ev_loop_destroy (EV_DEFAULT_UC);
		3142	}
		3143
		3144	...
		3145	atexit (program_exits);
		3146
		3147
3014	=head2 C<ev_async> - how to wake up another event loop	3148	=head2 C<ev_async> - how to wake up an event loop
3015		3149
3016	In general, you cannot use an C<ev_loop> from multiple threads or other	3150	In general, you cannot use an C<ev_run> from multiple threads or other
3017	asynchronous sources such as signal handlers (as opposed to multiple event	3151	asynchronous sources such as signal handlers (as opposed to multiple event
3018	loops - those are of course safe to use in different threads).	3152	loops - those are of course safe to use in different threads).
3019		3153
3020	Sometimes, however, you need to wake up another event loop you do not	3154	Sometimes, however, you need to wake up an event loop you do not control,
3021	control, for example because it belongs to another thread. This is what	3155	for example because it belongs to another thread. This is what C<ev_async>
3022	C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you	3156	watchers do: as long as the C<ev_async> watcher is active, you can signal
3023	can signal it by calling C<ev_async_send>, which is thread- and signal	3157	it by calling C<ev_async_send>, which is thread- and signal safe.
3024	safe.
3025		3158
3026	This functionality is very similar to C<ev_signal> watchers, as signals,	3159	This functionality is very similar to C<ev_signal> watchers, as signals,
3027	too, are asynchronous in nature, and signals, too, will be compressed	3160	too, are asynchronous in nature, and signals, too, will be compressed
3028	(i.e. the number of callback invocations may be less than the number of	3161	(i.e. the number of callback invocations may be less than the number of
3029	C<ev_async_sent> calls).	3162	C<ev_async_sent> calls).
…		…
3390	Associates a different C<struct ev_loop> with this watcher. You can only	3523	Associates a different C<struct ev_loop> with this watcher. You can only
3391	do this when the watcher is inactive (and not pending either).	3524	do this when the watcher is inactive (and not pending either).
3392		3525
3393	=item w->set ([arguments])	3526	=item w->set ([arguments])
3394		3527
3395	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3528	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3396	called at least once. Unlike the C counterpart, an active watcher gets	3529	method or a suitable start method must be called at least once. Unlike the
3397	automatically stopped and restarted when reconfiguring it with this	3530	C counterpart, an active watcher gets automatically stopped and restarted
3398	method.	3531	when reconfiguring it with this method.
3399		3532
3400	=item w->start ()	3533	=item w->start ()
3401		3534
3402	Starts the watcher. Note that there is no C<loop> argument, as the	3535	Starts the watcher. Note that there is no C<loop> argument, as the
3403	constructor already stores the event loop.	3536	constructor already stores the event loop.
3404		3537
		3538	=item w->start ([arguments])
		3539
		3540	Instead of calling C<set> and C<start> methods separately, it is often
		3541	convenient to wrap them in one call. Uses the same type of arguments as
		3542	the configure C<set> method of the watcher.
		3543
3405	=item w->stop ()	3544	=item w->stop ()
3406		3545
3407	Stops the watcher if it is active. Again, no C<loop> argument.	3546	Stops the watcher if it is active. Again, no C<loop> argument.
3408		3547
3409	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3548	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3421		3560
3422	=back	3561	=back
3423		3562
3424	=back	3563	=back
3425		3564
3426	Example: Define a class with an IO and idle watcher, start one of them in	3565	Example: Define a class with two I/O and idle watchers, start the I/O
3427	the constructor.	3566	watchers in the constructor.
3428		3567
3429	class myclass	3568	class myclass
3430	{	3569	{
3431	ev::io io ; void io_cb (ev::io &w, int revents);	3570	ev::io io ; void io_cb (ev::io &w, int revents);
		3571	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3432	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3572	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3433		3573
3434	myclass (int fd)	3574	myclass (int fd)
3435	{	3575	{
3436	io .set <myclass, &myclass::io_cb > (this);	3576	io .set <myclass, &myclass::io_cb > (this);
		3577	io2 .set <myclass, &myclass::io2_cb > (this);
3437	idle.set <myclass, &myclass::idle_cb> (this);	3578	idle.set <myclass, &myclass::idle_cb> (this);
3438		3579
3439	io.start (fd, ev::READ);	3580	io.set (fd, ev::WRITE); // configure the watcher
		3581	io.start (); // start it whenever convenient
		3582
		3583	io2.start (fd, ev::READ); // set + start in one call
3440	}	3584	}
3441	};	3585	};
3442		3586
3443		3587
3444	=head1 OTHER LANGUAGE BINDINGS	3588	=head1 OTHER LANGUAGE BINDINGS
…		…
3518	loop argument"). The C<EV_A> form is used when this is the sole argument,	3662	loop argument"). The C<EV_A> form is used when this is the sole argument,
3519	C<EV_A_> is used when other arguments are following. Example:	3663	C<EV_A_> is used when other arguments are following. Example:
3520		3664
3521	ev_unref (EV_A);	3665	ev_unref (EV_A);
3522	ev_timer_add (EV_A_ watcher);	3666	ev_timer_add (EV_A_ watcher);
3523	ev_loop (EV_A_ 0);	3667	ev_run (EV_A_ 0);
3524		3668
3525	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3669	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3526	which is often provided by the following macro.	3670	which is often provided by the following macro.
3527		3671
3528	=item C<EV_P>, C<EV_P_>	3672	=item C<EV_P>, C<EV_P_>
…		…
3568	}	3712	}
3569		3713
3570	ev_check check;	3714	ev_check check;
3571	ev_check_init (&check, check_cb);	3715	ev_check_init (&check, check_cb);
3572	ev_check_start (EV_DEFAULT_ &check);	3716	ev_check_start (EV_DEFAULT_ &check);
3573	ev_loop (EV_DEFAULT_ 0);	3717	ev_run (EV_DEFAULT_ 0);
3574		3718
3575	=head1 EMBEDDING	3719	=head1 EMBEDDING
3576		3720
3577	Libev can (and often is) directly embedded into host	3721	Libev can (and often is) directly embedded into host
3578	applications. Examples of applications that embed it include the Deliantra	3722	applications. Examples of applications that embed it include the Deliantra
…		…
3669	to a compiled library. All other symbols change the ABI, which means all	3813	to a compiled library. All other symbols change the ABI, which means all
3670	users of libev and the libev code itself must be compiled with compatible	3814	users of libev and the libev code itself must be compiled with compatible
3671	settings.	3815	settings.
3672		3816
3673	=over 4	3817	=over 4
		3818
		3819	=item EV_COMPAT3 (h)
		3820
		3821	Backwards compatibility is a major concern for libev. This is why this
		3822	release of libev comes with wrappers for the functions and symbols that
		3823	have been renamed between libev version 3 and 4.
		3824
		3825	You can disable these wrappers (to test compatibility with future
		3826	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3827	sources. This has the additional advantage that you can drop the C<struct>
		3828	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3829	typedef in that case.
		3830
		3831	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3832	and in some even more future version the compatibility code will be
		3833	removed completely.
3674		3834
3675	=item EV_STANDALONE (h)	3835	=item EV_STANDALONE (h)
3676		3836
3677	Must always be C<1> if you do not use autoconf configuration, which	3837	Must always be C<1> if you do not use autoconf configuration, which
3678	keeps libev from including F<config.h>, and it also defines dummy	3838	keeps libev from including F<config.h>, and it also defines dummy
…		…
3885	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,	4045	EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
3886	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.	4046	EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
3887		4047
3888	If undefined or defined to be C<1> (and the platform supports it), then	4048	If undefined or defined to be C<1> (and the platform supports it), then
3889	the respective watcher type is supported. If defined to be C<0>, then it	4049	the respective watcher type is supported. If defined to be C<0>, then it
3890	is not. Disabling watcher types mainly saves codesize.	4050	is not. Disabling watcher types mainly saves code size.
3891		4051
3892	=item EV_FEATURES	4052	=item EV_FEATURES
3893		4053
3894	If you need to shave off some kilobytes of code at the expense of some	4054	If you need to shave off some kilobytes of code at the expense of some
3895	speed (but with the full API), you can define this symbol to request	4055	speed (but with the full API), you can define this symbol to request
…		…
3915		4075
3916	=item C<1> - faster/larger code	4076	=item C<1> - faster/larger code
3917		4077
3918	Use larger code to speed up some operations.	4078	Use larger code to speed up some operations.
3919		4079
3920	Currently this is used to override some inlining decisions (enlarging the roughly	4080	Currently this is used to override some inlining decisions (enlarging the
3921	30% code size on amd64.	4081	code size by roughly 30% on amd64).
3922		4082
3923	When optimising for size, use of compiler flags such as C<-Os> with	4083	When optimising for size, use of compiler flags such as C<-Os> with
3924	gcc recommended, as well as C<-DNDEBUG>, as libev contains a number of	4084	gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
3925	assertions.	4085	assertions.
3926		4086
3927	=item C<2> - faster/larger data structures	4087	=item C<2> - faster/larger data structures
3928		4088
3929	Replaces the small 2-heap for timer management by a faster 4-heap, larger	4089	Replaces the small 2-heap for timer management by a faster 4-heap, larger
3930	hash table sizes and so on. This will usually further increase codesize	4090	hash table sizes and so on. This will usually further increase code size
3931	and can additionally have an effect on the size of data structures at	4091	and can additionally have an effect on the size of data structures at
3932	runtime.	4092	runtime.
3933		4093
3934	=item C<4> - full API configuration	4094	=item C<4> - full API configuration
3935		4095
…		…
3972	I/O watcher then might come out at only 5Kb.	4132	I/O watcher then might come out at only 5Kb.
3973		4133
3974	=item EV_AVOID_STDIO	4134	=item EV_AVOID_STDIO
3975		4135
3976	If this is set to C<1> at compiletime, then libev will avoid using stdio	4136	If this is set to C<1> at compiletime, then libev will avoid using stdio
3977	functions (printf, scanf, perror etc.). This will increase the codesize	4137	functions (printf, scanf, perror etc.). This will increase the code size
3978	somewhat, but if your program doesn't otherwise depend on stdio and your	4138	somewhat, but if your program doesn't otherwise depend on stdio and your
3979	libc allows it, this avoids linking in the stdio library which is quite	4139	libc allows it, this avoids linking in the stdio library which is quite
3980	big.	4140	big.
3981		4141
3982	Note that error messages might become less precise when this option is	4142	Note that error messages might become less precise when this option is
…		…
4028	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4188	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4029	will be C<0>.	4189	will be C<0>.
4030		4190
4031	=item EV_VERIFY	4191	=item EV_VERIFY
4032		4192
4033	Controls how much internal verification (see C<ev_loop_verify ()>) will	4193	Controls how much internal verification (see C<ev_verify ()>) will
4034	be done: If set to C<0>, no internal verification code will be compiled	4194	be done: If set to C<0>, no internal verification code will be compiled
4035	in. If set to C<1>, then verification code will be compiled in, but not	4195	in. If set to C<1>, then verification code will be compiled in, but not
4036	called. If set to C<2>, then the internal verification code will be	4196	called. If set to C<2>, then the internal verification code will be
4037	called once per loop, which can slow down libev. If set to C<3>, then the	4197	called once per loop, which can slow down libev. If set to C<3>, then the
4038	verification code will be called very frequently, which will slow down	4198	verification code will be called very frequently, which will slow down
…		…
4042	will be C<0>.	4202	will be C<0>.
4043		4203
4044	=item EV_COMMON	4204	=item EV_COMMON
4045		4205
4046	By default, all watchers have a C<void *data> member. By redefining	4206	By default, all watchers have a C<void *data> member. By redefining
4047	this macro to a something else you can include more and other types of	4207	this macro to something else you can include more and other types of
4048	members. You have to define it each time you include one of the files,	4208	members. You have to define it each time you include one of the files,
4049	though, and it must be identical each time.	4209	though, and it must be identical each time.
4050		4210
4051	For example, the perl EV module uses something like this:	4211	For example, the perl EV module uses something like this:
4052		4212
…		…
4253	userdata *u = ev_userdata (EV_A);	4413	userdata *u = ev_userdata (EV_A);
4254	pthread_mutex_lock (&u->lock);	4414	pthread_mutex_lock (&u->lock);
4255	}	4415	}
4256		4416
4257	The event loop thread first acquires the mutex, and then jumps straight	4417	The event loop thread first acquires the mutex, and then jumps straight
4258	into C<ev_loop>:	4418	into C<ev_run>:
4259		4419
4260	void *	4420	void *
4261	l_run (void *thr_arg)	4421	l_run (void *thr_arg)
4262	{	4422	{
4263	struct ev_loop *loop = (struct ev_loop *)thr_arg;	4423	struct ev_loop *loop = (struct ev_loop *)thr_arg;
4264		4424
4265	l_acquire (EV_A);	4425	l_acquire (EV_A);
4266	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4426	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4267	ev_loop (EV_A_ 0);	4427	ev_run (EV_A_ 0);
4268	l_release (EV_A);	4428	l_release (EV_A);
4269		4429
4270	return 0;	4430	return 0;
4271	}	4431	}
4272		4432
…		…
4324		4484
4325	=head3 COROUTINES	4485	=head3 COROUTINES
4326		4486
4327	Libev is very accommodating to coroutines ("cooperative threads"):	4487	Libev is very accommodating to coroutines ("cooperative threads"):
4328	libev fully supports nesting calls to its functions from different	4488	libev fully supports nesting calls to its functions from different
4329	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4489	coroutines (e.g. you can call C<ev_run> on the same loop from two
4330	different coroutines, and switch freely between both coroutines running	4490	different coroutines, and switch freely between both coroutines running
4331	the loop, as long as you don't confuse yourself). The only exception is	4491	the loop, as long as you don't confuse yourself). The only exception is
4332	that you must not do this from C<ev_periodic> reschedule callbacks.	4492	that you must not do this from C<ev_periodic> reschedule callbacks.
4333		4493
4334	Care has been taken to ensure that libev does not keep local state inside	4494	Care has been taken to ensure that libev does not keep local state inside
4335	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4495	C<ev_run>, and other calls do not usually allow for coroutine switches as
4336	they do not call any callbacks.	4496	they do not call any callbacks.
4337		4497
4338	=head2 COMPILER WARNINGS	4498	=head2 COMPILER WARNINGS
4339		4499
4340	Depending on your compiler and compiler settings, you might get no or a	4500	Depending on your compiler and compiler settings, you might get no or a
…		…
4351	maintainable.	4511	maintainable.
4352		4512
4353	And of course, some compiler warnings are just plain stupid, or simply	4513	And of course, some compiler warnings are just plain stupid, or simply
4354	wrong (because they don't actually warn about the condition their message	4514	wrong (because they don't actually warn about the condition their message
4355	seems to warn about). For example, certain older gcc versions had some	4515	seems to warn about). For example, certain older gcc versions had some
4356	warnings that resulted an extreme number of false positives. These have	4516	warnings that resulted in an extreme number of false positives. These have
4357	been fixed, but some people still insist on making code warn-free with	4517	been fixed, but some people still insist on making code warn-free with
4358	such buggy versions.	4518	such buggy versions.
4359		4519
4360	While libev is written to generate as few warnings as possible,	4520	While libev is written to generate as few warnings as possible,
4361	"warn-free" code is not a goal, and it is recommended not to build libev	4521	"warn-free" code is not a goal, and it is recommended not to build libev
…		…
4397	I suggest using suppression lists.	4557	I suggest using suppression lists.
4398		4558
4399		4559
4400	=head1 PORTABILITY NOTES	4560	=head1 PORTABILITY NOTES
4401		4561
		4562	=head2 GNU/LINUX 32 BIT LIMITATIONS
		4563
		4564	GNU/Linux is the only common platform that supports 64 bit file/large file
		4565	interfaces but I<disables> them by default.
		4566
		4567	That means that libev compiled in the default environment doesn't support
		4568	files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
		4569
		4570	Unfortunately, many programs try to work around this GNU/Linux issue
		4571	by enabling the large file API, which makes them incompatible with the
		4572	standard libev compiled for their system.
		4573
		4574	Likewise, libev cannot enable the large file API itself as this would
		4575	suddenly make it incompatible to the default compile time environment,
		4576	i.e. all programs not using special compile switches.
		4577
		4578	=head2 OS/X AND DARWIN BUGS
		4579
		4580	The whole thing is a bug if you ask me - basically any system interface
		4581	you touch is broken, whether it is locales, poll, kqueue or even the
		4582	OpenGL drivers.
		4583
		4584	=head3 C<kqueue> is buggy
		4585
		4586	The kqueue syscall is broken in all known versions - most versions support
		4587	only sockets, many support pipes.
		4588
		4589	Libev tries to work around this by not using C<kqueue> by default on this
		4590	rotten platform, but of course you can still ask for it when creating a
		4591	loop - embedding a socket-only kqueue loop into a select-based one is
		4592	probably going to work well.
		4593
		4594	=head3 C<poll> is buggy
		4595
		4596	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
		4597	implementation by something calling C<kqueue> internally around the 10.5.6
		4598	release, so now C<kqueue> I<and> C<poll> are broken.
		4599
		4600	Libev tries to work around this by not using C<poll> by default on
		4601	this rotten platform, but of course you can still ask for it when creating
		4602	a loop.
		4603
		4604	=head3 C<select> is buggy
		4605
		4606	All that's left is C<select>, and of course Apple found a way to fuck this
		4607	one up as well: On OS/X, C<select> actively limits the number of file
		4608	descriptors you can pass in to 1024 - your program suddenly crashes when
		4609	you use more.
		4610
		4611	There is an undocumented "workaround" for this - defining
		4612	C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
		4613	work on OS/X.
		4614
		4615	=head2 SOLARIS PROBLEMS AND WORKAROUNDS
		4616
		4617	=head3 C<errno> reentrancy
		4618
		4619	The default compile environment on Solaris is unfortunately so
		4620	thread-unsafe that you can't even use components/libraries compiled
		4621	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
		4622	defined by default. A valid, if stupid, implementation choice.
		4623
		4624	If you want to use libev in threaded environments you have to make sure
		4625	it's compiled with C<_REENTRANT> defined.
		4626
		4627	=head3 Event port backend
		4628
		4629	The scalable event interface for Solaris is called "event
		4630	ports". Unfortunately, this mechanism is very buggy in all major
		4631	releases. If you run into high CPU usage, your program freezes or you get
		4632	a large number of spurious wakeups, make sure you have all the relevant
		4633	and latest kernel patches applied. No, I don't know which ones, but there
		4634	are multiple ones to apply, and afterwards, event ports actually work
		4635	great.
		4636
		4637	If you can't get it to work, you can try running the program by setting
		4638	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
		4639	C<select> backends.
		4640
		4641	=head2 AIX POLL BUG
		4642
		4643	AIX unfortunately has a broken C<poll.h> header. Libev works around
		4644	this by trying to avoid the poll backend altogether (i.e. it's not even
		4645	compiled in), which normally isn't a big problem as C<select> works fine
		4646	with large bitsets on AIX, and AIX is dead anyway.
		4647
4402	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4648	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
		4649
		4650	=head3 General issues
4403		4651
4404	Win32 doesn't support any of the standards (e.g. POSIX) that libev	4652	Win32 doesn't support any of the standards (e.g. POSIX) that libev
4405	requires, and its I/O model is fundamentally incompatible with the POSIX	4653	requires, and its I/O model is fundamentally incompatible with the POSIX
4406	model. Libev still offers limited functionality on this platform in	4654	model. Libev still offers limited functionality on this platform in
4407	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	4655	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4408	descriptors. This only applies when using Win32 natively, not when using	4656	descriptors. This only applies when using Win32 natively, not when using
4409	e.g. cygwin.	4657	e.g. cygwin. Actually, it only applies to the microsofts own compilers,
		4658	as every compielr comes with a slightly differently broken/incompatible
		4659	environment.
4410		4660
4411	Lifting these limitations would basically require the full	4661	Lifting these limitations would basically require the full
4412	re-implementation of the I/O system. If you are into these kinds of	4662	re-implementation of the I/O system. If you are into this kind of thing,
4413	things, then note that glib does exactly that for you in a very portable	4663	then note that glib does exactly that for you in a very portable way (note
4414	way (note also that glib is the slowest event library known to man).	4664	also that glib is the slowest event library known to man).
4415		4665
4416	There is no supported compilation method available on windows except	4666	There is no supported compilation method available on windows except
4417	embedding it into other applications.	4667	embedding it into other applications.
4418		4668
4419	Sensible signal handling is officially unsupported by Microsoft - libev	4669	Sensible signal handling is officially unsupported by Microsoft - libev
…		…
4447	you do I<not> compile the F<ev.c> or any other embedded source files!):	4697	you do I<not> compile the F<ev.c> or any other embedded source files!):
4448		4698
4449	#include "evwrap.h"	4699	#include "evwrap.h"
4450	#include "ev.c"	4700	#include "ev.c"
4451		4701
4452	=over 4
4453
4454	=item The winsocket select function	4702	=head3 The winsocket C<select> function
4455		4703
4456	The winsocket C<select> function doesn't follow POSIX in that it	4704	The winsocket C<select> function doesn't follow POSIX in that it
4457	requires socket I<handles> and not socket I<file descriptors> (it is	4705	requires socket I<handles> and not socket I<file descriptors> (it is
4458	also extremely buggy). This makes select very inefficient, and also	4706	also extremely buggy). This makes select very inefficient, and also
4459	requires a mapping from file descriptors to socket handles (the Microsoft	4707	requires a mapping from file descriptors to socket handles (the Microsoft
…		…
4468	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	4716	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
4469		4717
4470	Note that winsockets handling of fd sets is O(n), so you can easily get a	4718	Note that winsockets handling of fd sets is O(n), so you can easily get a
4471	complexity in the O(n²) range when using win32.	4719	complexity in the O(n²) range when using win32.
4472		4720
4473	=item Limited number of file descriptors	4721	=head3 Limited number of file descriptors
4474		4722
4475	Windows has numerous arbitrary (and low) limits on things.	4723	Windows has numerous arbitrary (and low) limits on things.
4476		4724
4477	Early versions of winsocket's select only supported waiting for a maximum	4725	Early versions of winsocket's select only supported waiting for a maximum
4478	of C<64> handles (probably owning to the fact that all windows kernels	4726	of C<64> handles (probably owning to the fact that all windows kernels
…		…
4493	runtime libraries. This might get you to about C<512> or C<2048> sockets	4741	runtime libraries. This might get you to about C<512> or C<2048> sockets
4494	(depending on windows version and/or the phase of the moon). To get more,	4742	(depending on windows version and/or the phase of the moon). To get more,
4495	you need to wrap all I/O functions and provide your own fd management, but	4743	you need to wrap all I/O functions and provide your own fd management, but
4496	the cost of calling select (O(n²)) will likely make this unworkable.	4744	the cost of calling select (O(n²)) will likely make this unworkable.
4497		4745
4498	=back
4499
4500	=head2 PORTABILITY REQUIREMENTS	4746	=head2 PORTABILITY REQUIREMENTS
4501		4747
4502	In addition to a working ISO-C implementation and of course the	4748	In addition to a working ISO-C implementation and of course the
4503	backend-specific APIs, libev relies on a few additional extensions:	4749	backend-specific APIs, libev relies on a few additional extensions:
4504		4750
…		…
4542	watchers.	4788	watchers.
4543		4789
4544	=item C<double> must hold a time value in seconds with enough accuracy	4790	=item C<double> must hold a time value in seconds with enough accuracy
4545		4791
4546	The type C<double> is used to represent timestamps. It is required to	4792	The type C<double> is used to represent timestamps. It is required to
4547	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4793	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4548	enough for at least into the year 4000. This requirement is fulfilled by	4794	good enough for at least into the year 4000 with millisecond accuracy
		4795	(the design goal for libev). This requirement is overfulfilled by
4549	implementations implementing IEEE 754, which is basically all existing	4796	implementations using IEEE 754, which is basically all existing ones. With
4550	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4797	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4551	2200.
4552		4798
4553	=back	4799	=back
4554		4800
4555	If you know of other additional requirements drop me a note.	4801	If you know of other additional requirements drop me a note.
4556		4802
…		…
4634	compatibility, so most programs should still compile. Those might be	4880	compatibility, so most programs should still compile. Those might be
4635	removed in later versions of libev, so better update early than late.	4881	removed in later versions of libev, so better update early than late.
4636		4882
4637	=over 4	4883	=over 4
4638		4884
4639	=item C<ev_loop_count> renamed to C<ev_iteration>	4885	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
4640		4886
4641	=item C<ev_loop_depth> renamed to C<ev_depth>	4887	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
4642		4888
4643	=item C<ev_loop_verify> renamed to C<ev_verify>	4889	ev_loop_destroy (EV_DEFAULT_UC);
		4890	ev_loop_fork (EV_DEFAULT);
		4891
		4892	=item function/symbol renames
		4893
		4894	A number of functions and symbols have been renamed:
		4895
		4896	ev_loop => ev_run
		4897	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4898	EVLOOP_ONESHOT => EVRUN_ONCE
		4899
		4900	ev_unloop => ev_break
		4901	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4902	EVUNLOOP_ONE => EVBREAK_ONE
		4903	EVUNLOOP_ALL => EVBREAK_ALL
		4904
		4905	EV_TIMEOUT => EV_TIMER
		4906
		4907	ev_loop_count => ev_iteration
		4908	ev_loop_depth => ev_depth
		4909	ev_loop_verify => ev_verify
4644		4910
4645	Most functions working on C<struct ev_loop> objects don't have an	4911	Most functions working on C<struct ev_loop> objects don't have an
4646	C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is	4912	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4913	associated constants have been renamed to not collide with the C<struct
		4914	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4915	as all other watcher types. Note that C<ev_loop_fork> is still called
4647	still called C<ev_loop_fork> because it would otherwise clash with the	4916	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4648	C<ev_fork> typedef.	4917	typedef.
4649		4918
4650	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>	4919	=item C<EV_COMPAT3> backwards compatibility mechanism
4651		4920
4652	This is a simple rename - all other watcher types use their name	4921	The backward compatibility mechanism can be controlled by
4653	as revents flag, and now C<ev_timer> does, too.	4922	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4654		4923	section.
4655	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4656	and continue to be present for the foreseeable future, so this is mostly a
4657	documentation change.
4658		4924
4659	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4925	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4660		4926
4661	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4927	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4662	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4928	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
…		…
4669		4935
4670	=over 4	4936	=over 4
4671		4937
4672	=item active	4938	=item active
4673		4939
4674	A watcher is active as long as it has been started (has been attached to	4940	A watcher is active as long as it has been started and not yet stopped.
4675	an event loop) but not yet stopped (disassociated from the event loop).	4941	See L<WATCHER STATES> for details.
4676		4942
4677	=item application	4943	=item application
4678		4944
4679	In this document, an application is whatever is using libev.	4945	In this document, an application is whatever is using libev.
		4946
		4947	=item backend
		4948
		4949	The part of the code dealing with the operating system interfaces.
4680		4950
4681	=item callback	4951	=item callback
4682		4952
4683	The address of a function that is called when some event has been	4953	The address of a function that is called when some event has been
4684	detected. Callbacks are being passed the event loop, the watcher that	4954	detected. Callbacks are being passed the event loop, the watcher that
4685	received the event, and the actual event bitset.	4955	received the event, and the actual event bitset.
4686		4956
4687	=item callback invocation	4957	=item callback/watcher invocation
4688		4958
4689	The act of calling the callback associated with a watcher.	4959	The act of calling the callback associated with a watcher.
4690		4960
4691	=item event	4961	=item event
4692		4962
…		…
4711	The model used to describe how an event loop handles and processes	4981	The model used to describe how an event loop handles and processes
4712	watchers and events.	4982	watchers and events.
4713		4983
4714	=item pending	4984	=item pending
4715		4985
4716	A watcher is pending as soon as the corresponding event has been detected,	4986	A watcher is pending as soon as the corresponding event has been
4717	and stops being pending as soon as the watcher will be invoked or its	4987	detected. See L<WATCHER STATES> for details.
4718	pending status is explicitly cleared by the application.
4719
4720	A watcher can be pending, but not active. Stopping a watcher also clears
4721	its pending status.
4722		4988
4723	=item real time	4989	=item real time
4724		4990
4725	The physical time that is observed. It is apparently strictly monotonic :)	4991	The physical time that is observed. It is apparently strictly monotonic :)
4726		4992
…		…
4733	=item watcher	4999	=item watcher
4734		5000
4735	A data structure that describes interest in certain events. Watchers need	5001	A data structure that describes interest in certain events. Watchers need
4736	to be started (attached to an event loop) before they can receive events.	5002	to be started (attached to an event loop) before they can receive events.
4737		5003
4738	=item watcher invocation
4739
4740	The act of calling the callback associated with a watcher.
4741
4742	=back	5004	=back
4743		5005
4744	=head1 AUTHOR	5006	=head1 AUTHOR
4745		5007
4746	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5008	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.

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