[ViewVC] Diff of: cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.305 by root, Thu Oct 14 05:07:04 2010 UTC vs.
Revision 1.340 by root, Wed Nov 3 20:03:21 2010 UTC

…		…
26	puts ("stdin ready");	26	puts ("stdin ready");
27	// for one-shot events, one must manually stop the watcher	27	// for one-shot events, one must manually stop the watcher
28	// with its corresponding stop function.	28	// with its corresponding stop function.
29	ev_io_stop (EV_A_ w);	29	ev_io_stop (EV_A_ w);
30		30
31	// this causes all nested ev_loop's to stop iterating	31	// this causes all nested ev_run's to stop iterating
32	ev_unloop (EV_A_ EVUNLOOP_ALL);	32	ev_break (EV_A_ EVBREAK_ALL);
33	}	33	}
34		34
35	// another callback, this time for a time-out	35	// another callback, this time for a time-out
36	static void	36	static void
37	timeout_cb (EV_P_ ev_timer *w, int revents)	37	timeout_cb (EV_P_ ev_timer *w, int revents)
38	{	38	{
39	puts ("timeout");	39	puts ("timeout");
40	// this causes the innermost ev_loop to stop iterating	40	// this causes the innermost ev_run to stop iterating
41	ev_unloop (EV_A_ EVUNLOOP_ONE);	41	ev_break (EV_A_ EVBREAK_ONE);
42	}	42	}
43		43
44	int	44	int
45	main (void)	45	main (void)
46	{	46	{
47	// use the default event loop unless you have special needs	47	// use the default event loop unless you have special needs
48	struct ev_loop *loop = ev_default_loop (0);	48	struct ev_loop *loop = EV_DEFAULT;
49		49
50	// initialise an io watcher, then start it	50	// initialise an io watcher, then start it
51	// this one will watch for stdin to become readable	51	// this one will watch for stdin to become readable
52	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);	52	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
53	ev_io_start (loop, &stdin_watcher);	53	ev_io_start (loop, &stdin_watcher);
…		…
56	// simple non-repeating 5.5 second timeout	56	// simple non-repeating 5.5 second timeout
57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	57	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
58	ev_timer_start (loop, &timeout_watcher);	58	ev_timer_start (loop, &timeout_watcher);
59		59
60	// now wait for events to arrive	60	// now wait for events to arrive
61	ev_loop (loop, 0);	61	ev_run (loop, 0);
62		62
63	// unloop was called, so exit	63	// unloop was called, so exit
64	return 0;	64	return 0;
65	}	65	}
66		66
…		…
77	on event-based programming, nor will it introduce event-based programming	77	on event-based programming, nor will it introduce event-based programming
78	with libev.	78	with libev.
79		79
80	Familiarity with event based programming techniques in general is assumed	80	Familiarity with event based programming techniques in general is assumed
81	throughout this document.	81	throughout this document.
		82
		83	=head1 WHAT TO READ WHEN IN A HURRY
		84
		85	This manual tries to be very detailed, but unfortunately, this also makes
		86	it very long. If you just want to know the basics of libev, I suggest
		87	reading L<ANATOMY OF A WATCHER>, then the L<EXAMPLE PROGRAM> above and
		88	look up the missing functions in L<GLOBAL FUNCTIONS> and the C<ev_io> and
		89	C<ev_timer> sections in L<WATCHER TYPES>.
82		90
83	=head1 ABOUT LIBEV	91	=head1 ABOUT LIBEV
84		92
85	Libev is an event loop: you register interest in certain events (such as a	93	Libev is an event loop: you register interest in certain events (such as a
86	file descriptor being readable or a timeout occurring), and it will manage	94	file descriptor being readable or a timeout occurring), and it will manage
…		…
124	this argument.	132	this argument.
125		133
126	=head2 TIME REPRESENTATION	134	=head2 TIME REPRESENTATION
127		135
128	Libev represents time as a single floating point number, representing	136	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (in practise	137	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	somewhere near the beginning of 1970, details are complicated, don't	138	somewhere near the beginning of 1970, details are complicated, don't
131	ask). This type is called C<ev_tstamp>, which is what you should use	139	ask). This type is called C<ev_tstamp>, which is what you should use
132	too. It usually aliases to the C<double> type in C. When you need to do	140	too. It usually aliases to the C<double> type in C. When you need to do
133	any calculations on it, you should treat it as some floating point value.	141	any calculations on it, you should treat it as some floating point value.
134		142
…		…
165		173
166	=item ev_tstamp ev_time ()	174	=item ev_tstamp ev_time ()
167		175
168	Returns the current time as libev would use it. Please note that the	176	Returns the current time as libev would use it. Please note that the
169	C<ev_now> function is usually faster and also often returns the timestamp	177	C<ev_now> function is usually faster and also often returns the timestamp
170	you actually want to know.	178	you actually want to know. Also interesting is the combination of
		179	C<ev_update_now> and C<ev_now>.
171		180
172	=item ev_sleep (ev_tstamp interval)	181	=item ev_sleep (ev_tstamp interval)
173		182
174	Sleep for the given interval: The current thread will be blocked until	183	Sleep for the given interval: The current thread will be blocked until
175	either it is interrupted or the given time interval has passed. Basically	184	either it is interrupted or the given time interval has passed. Basically
…		…
192	as this indicates an incompatible change. Minor versions are usually	201	as this indicates an incompatible change. Minor versions are usually
193	compatible to older versions, so a larger minor version alone is usually	202	compatible to older versions, so a larger minor version alone is usually
194	not a problem.	203	not a problem.
195		204
196	Example: Make sure we haven't accidentally been linked against the wrong	205	Example: Make sure we haven't accidentally been linked against the wrong
197	version (note, however, that this will not detect ABI mismatches :).	206	version (note, however, that this will not detect other ABI mismatches,
		207	such as LFS or reentrancy).
198		208
199	assert (("libev version mismatch",	209	assert (("libev version mismatch",
200	ev_version_major () == EV_VERSION_MAJOR	210	ev_version_major () == EV_VERSION_MAJOR
201	&& ev_version_minor () >= EV_VERSION_MINOR));	211	&& ev_version_minor () >= EV_VERSION_MINOR));
202		212
…		…
213	assert (("sorry, no epoll, no sex",	223	assert (("sorry, no epoll, no sex",
214	ev_supported_backends () & EVBACKEND_EPOLL));	224	ev_supported_backends () & EVBACKEND_EPOLL));
215		225
216	=item unsigned int ev_recommended_backends ()	226	=item unsigned int ev_recommended_backends ()
217		227
218	Return the set of all backends compiled into this binary of libev and also	228	Return the set of all backends compiled into this binary of libev and
219	recommended for this platform. This set is often smaller than the one	229	also recommended for this platform, meaning it will work for most file
		230	descriptor types. This set is often smaller than the one returned by
220	returned by C<ev_supported_backends>, as for example kqueue is broken on	231	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
221	most BSDs and will not be auto-detected unless you explicitly request it	232	and will not be auto-detected unless you explicitly request it (assuming
222	(assuming you know what you are doing). This is the set of backends that	233	you know what you are doing). This is the set of backends that libev will
223	libev will probe for if you specify no backends explicitly.	234	probe for if you specify no backends explicitly.
224		235
225	=item unsigned int ev_embeddable_backends ()	236	=item unsigned int ev_embeddable_backends ()
226		237
227	Returns the set of backends that are embeddable in other event loops. This	238	Returns the set of backends that are embeddable in other event loops. This
228	is the theoretical, all-platform, value. To find which backends	239	value is platform-specific but can include backends not available on the
229	might be supported on the current system, you would need to look at	240	current system. To find which embeddable backends might be supported on
230	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	241	the current system, you would need to look at C<ev_embeddable_backends ()
231	recommended ones.	242	& ev_supported_backends ()>, likewise for recommended ones.
232		243
233	See the description of C<ev_embed> watchers for more info.	244	See the description of C<ev_embed> watchers for more info.
234		245
235	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]	246	=item ev_set_allocator (void (cb)(void *ptr, long size))
236		247
237	Sets the allocation function to use (the prototype is similar - the	248	Sets the allocation function to use (the prototype is similar - the
238	semantics are identical to the C<realloc> C89/SuS/POSIX function). It is	249	semantics are identical to the C<realloc> C89/SuS/POSIX function). It is
239	used to allocate and free memory (no surprises here). If it returns zero	250	used to allocate and free memory (no surprises here). If it returns zero
240	when memory needs to be allocated (C<size != 0>), the library might abort	251	when memory needs to be allocated (C<size != 0>), the library might abort
…		…
266	}	277	}
267		278
268	...	279	...
269	ev_set_allocator (persistent_realloc);	280	ev_set_allocator (persistent_realloc);
270		281
271	=item ev_set_syserr_cb (void (cb)(const char msg)); [NOT REENTRANT]	282	=item ev_set_syserr_cb (void (cb)(const char msg))
272		283
273	Set the callback function to call on a retryable system call error (such	284	Set the callback function to call on a retryable system call error (such
274	as failed select, poll, epoll_wait). The message is a printable string	285	as failed select, poll, epoll_wait). The message is a printable string
275	indicating the system call or subsystem causing the problem. If this	286	indicating the system call or subsystem causing the problem. If this
276	callback is set, then libev will expect it to remedy the situation, no	287	callback is set, then libev will expect it to remedy the situation, no
…		…
290	...	301	...
291	ev_set_syserr_cb (fatal_error);	302	ev_set_syserr_cb (fatal_error);
292		303
293	=back	304	=back
294		305
295	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	306	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
296		307
297	An event loop is described by a C<struct ev_loop *> (the C<struct>	308	An event loop is described by a C<struct ev_loop *> (the C<struct> is
298	is I<not> optional in this case, as there is also an C<ev_loop>	309	I<not> optional in this case unless libev 3 compatibility is disabled, as
299	I<function>).	310	libev 3 had an C<ev_loop> function colliding with the struct name).
300		311
301	The library knows two types of such loops, the I<default> loop, which	312	The library knows two types of such loops, the I<default> loop, which
302	supports signals and child events, and dynamically created loops which do	313	supports child process events, and dynamically created event loops which
303	not.	314	do not.
304		315
305	=over 4	316	=over 4
306		317
307	=item struct ev_loop *ev_default_loop (unsigned int flags)	318	=item struct ev_loop *ev_default_loop (unsigned int flags)
308		319
309	This will initialise the default event loop if it hasn't been initialised	320	This returns the "default" event loop object, which is what you should
310	yet and return it. If the default loop could not be initialised, returns	321	normally use when you just need "the event loop". Event loop objects and
311	false. If it already was initialised it simply returns it (and ignores the	322	the C<flags> parameter are described in more detail in the entry for
312	flags. If that is troubling you, check C<ev_backend ()> afterwards).	323	C<ev_loop_new>.
		324
		325	If the default loop is already initialised then this function simply
		326	returns it (and ignores the flags. If that is troubling you, check
		327	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		328	flags, which should almost always be C<0>, unless the caller is also the
		329	one calling C<ev_run> or otherwise qualifies as "the main program".
313		330
314	If you don't know what event loop to use, use the one returned from this	331	If you don't know what event loop to use, use the one returned from this
315	function.	332	function (or via the C<EV_DEFAULT> macro).
316		333
317	Note that this function is I<not> thread-safe, so if you want to use it	334	Note that this function is I<not> thread-safe, so if you want to use it
318	from multiple threads, you have to lock (note also that this is unlikely,	335	from multiple threads, you have to employ some kind of mutex (note also
319	as loops cannot be shared easily between threads anyway).	336	that this case is unlikely, as loops cannot be shared easily between
		337	threads anyway).
320		338
321	The default loop is the only loop that can handle C<ev_signal> and	339	The default loop is the only loop that can handle C<ev_child> watchers,
322	C<ev_child> watchers, and to do this, it always registers a handler	340	and to do this, it always registers a handler for C<SIGCHLD>. If this is
323	for C<SIGCHLD>. If this is a problem for your application you can either	341	a problem for your application you can either create a dynamic loop with
324	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	342	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
325	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	343	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
326	C<ev_default_init>.	344
		345	Example: This is the most typical usage.
		346
		347	if (!ev_default_loop (0))
		348	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		349
		350	Example: Restrict libev to the select and poll backends, and do not allow
		351	environment settings to be taken into account:
		352
		353	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
		354
		355	=item struct ev_loop *ev_loop_new (unsigned int flags)
		356
		357	This will create and initialise a new event loop object. If the loop
		358	could not be initialised, returns false.
		359
		360	Note that this function I<is> thread-safe, and one common way to use
		361	libev with threads is indeed to create one loop per thread, and using the
		362	default loop in the "main" or "initial" thread.
327		363
328	The flags argument can be used to specify special behaviour or specific	364	The flags argument can be used to specify special behaviour or specific
329	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	365	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
330		366
331	The following flags are supported:	367	The following flags are supported:
…		…
366	environment variable.	402	environment variable.
367		403
368	=item C<EVFLAG_NOINOTIFY>	404	=item C<EVFLAG_NOINOTIFY>
369		405
370	When this flag is specified, then libev will not attempt to use the	406	When this flag is specified, then libev will not attempt to use the
371	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and	407	I<inotify> API for its C<ev_stat> watchers. Apart from debugging and
372	testing, this flag can be useful to conserve inotify file descriptors, as	408	testing, this flag can be useful to conserve inotify file descriptors, as
373	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.	409	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
374		410
375	=item C<EVFLAG_SIGNALFD>	411	=item C<EVFLAG_SIGNALFD>
376		412
377	When this flag is specified, then libev will attempt to use the	413	When this flag is specified, then libev will attempt to use the
378	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API	414	I<signalfd> API for its C<ev_signal> (and C<ev_child>) watchers. This API
379	delivers signals synchronously, which makes it both faster and might make	415	delivers signals synchronously, which makes it both faster and might make
380	it possible to get the queued signal data. It can also simplify signal	416	it possible to get the queued signal data. It can also simplify signal
381	handling with threads, as long as you properly block signals in your	417	handling with threads, as long as you properly block signals in your
382	threads that are not interested in handling them.	418	threads that are not interested in handling them.
383		419
…		…
427	epoll scales either O(1) or O(active_fds).	463	epoll scales either O(1) or O(active_fds).
428		464
429	The epoll mechanism deserves honorable mention as the most misdesigned	465	The epoll mechanism deserves honorable mention as the most misdesigned
430	of the more advanced event mechanisms: mere annoyances include silently	466	of the more advanced event mechanisms: mere annoyances include silently
431	dropping file descriptors, requiring a system call per change per file	467	dropping file descriptors, requiring a system call per change per file
432	descriptor (and unnecessary guessing of parameters), problems with dup and	468	descriptor (and unnecessary guessing of parameters), problems with dup,
		469	returning before the timeout value, resulting in additional iterations
		470	(and only giving 5ms accuracy while select on the same platform gives
433	so on. The biggest issue is fork races, however - if a program forks then	471	0.1ms) and so on. The biggest issue is fork races, however - if a program
434	I<both> parent and child process have to recreate the epoll set, which can	472	forks then I<both> parent and child process have to recreate the epoll
435	take considerable time (one syscall per file descriptor) and is of course	473	set, which can take considerable time (one syscall per file descriptor)
436	hard to detect.	474	and is of course hard to detect.
437		475
438	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but	476	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but
439	of course I<doesn't>, and epoll just loves to report events for totally	477	of course I<doesn't>, and epoll just loves to report events for totally
440	I<different> file descriptors (even already closed ones, so one cannot	478	I<different> file descriptors (even already closed ones, so one cannot
441	even remove them from the set) than registered in the set (especially	479	even remove them from the set) than registered in the set (especially
442	on SMP systems). Libev tries to counter these spurious notifications by	480	on SMP systems). Libev tries to counter these spurious notifications by
443	employing an additional generation counter and comparing that against the	481	employing an additional generation counter and comparing that against the
444	events to filter out spurious ones, recreating the set when required.	482	events to filter out spurious ones, recreating the set when required. Last
		483	not least, it also refuses to work with some file descriptors which work
		484	perfectly fine with C<select> (files, many character devices...).
		485
		486	Epoll is truly the train wreck analog among event poll mechanisms.
445		487
446	While stopping, setting and starting an I/O watcher in the same iteration	488	While stopping, setting and starting an I/O watcher in the same iteration
447	will result in some caching, there is still a system call per such	489	will result in some caching, there is still a system call per such
448	incident (because the same I<file descriptor> could point to a different	490	incident (because the same I<file descriptor> could point to a different
449	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	491	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
…		…
547	If one or more of the backend flags are or'ed into the flags value,	589	If one or more of the backend flags are or'ed into the flags value,
548	then only these backends will be tried (in the reverse order as listed	590	then only these backends will be tried (in the reverse order as listed
549	here). If none are specified, all backends in C<ev_recommended_backends	591	here). If none are specified, all backends in C<ev_recommended_backends
550	()> will be tried.	592	()> will be tried.
551		593
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.	594	Example: Try to create a event loop that uses epoll and nothing else.
579		595
580	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	596	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
581	if (!epoller)	597	if (!epoller)
582	fatal ("no epoll found here, maybe it hides under your chair");	598	fatal ("no epoll found here, maybe it hides under your chair");
583		599
		600	Example: Use whatever libev has to offer, but make sure that kqueue is
		601	used if available.
		602
		603	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () \| EVBACKEND_KQUEUE);
		604
584	=item ev_default_destroy ()	605	=item ev_loop_destroy (loop)
585		606
586	Destroys the default loop (frees all memory and kernel state etc.). None	607	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	608	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	609	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,	610	responsibility to either stop all watchers cleanly yourself I<before>
590	or cope with the fact afterwards (which is usually the easiest thing, you	611	calling this function, or cope with the fact afterwards (which is usually
591	can just ignore the watchers and/or C<free ()> them for example).	612	the easiest thing, you can just ignore the watchers and/or C<free ()> them
		613	for example).
592		614
593	Note that certain global state, such as signal state (and installed signal	615	Note that certain global state, such as signal state (and installed signal
594	handlers), will not be freed by this function, and related watchers (such	616	handlers), will not be freed by this function, and related watchers (such
595	as signal and child watchers) would need to be stopped manually.	617	as signal and child watchers) would need to be stopped manually.
596		618
597	In general it is not advisable to call this function except in the	619	This function is normally used on loop objects allocated by
598	rare occasion where you really need to free e.g. the signal handling	620	C<ev_loop_new>, but it can also be used on the default loop returned by
		621	C<ev_default_loop>, in which case it is not thread-safe.
		622
		623	Note that it is not advisable to call this function on the default loop
		624	except in the rare occasion where you really need to free its resources.
599	pipe fds. If you need dynamically allocated loops it is better to use	625	If you need dynamically allocated loops it is better to use C<ev_loop_new>
600	C<ev_loop_new> and C<ev_loop_destroy>.	626	and C<ev_loop_destroy>.
601		627
602	=item ev_loop_destroy (loop)	628	=item ev_loop_fork (loop)
603		629
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	630	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	631	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	632	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	633	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	634	child before resuming or calling C<ev_run>.
614	functions, and it will only take effect at the next C<ev_loop> iteration.
615		635
616	Again, you I<have> to call it on I<any> loop that you want to re-use after	636	Again, you I<have> to call it on I<any> loop that you want to re-use after
617	a fork, I<even if you do not plan to use the loop in the parent>. This is	637	a fork, I<even if you do not plan to use the loop in the parent>. This is
618	because some kernel interfaces cough I<kqueue> cough do funny things	638	because some kernel interfaces cough I<kqueue> cough do funny things
619	during fork.	639	during fork.
620		640
621	On the other hand, you only need to call this function in the child	641	On the other hand, you only need to call this function in the child
622	process if and only if you want to use the event loop in the child. If you	642	process if and only if you want to use the event loop in the child. If
623	just fork+exec or create a new loop in the child, you don't have to call	643	you just fork+exec or create a new loop in the child, you don't have to
624	it at all.	644	call it at all (in fact, C<epoll> is so badly broken that it makes a
		645	difference, but libev will usually detect this case on its own and do a
		646	costly reset of the backend).
625		647
626	The function itself is quite fast and it's usually not a problem to call	648	The function itself is quite fast and it's usually not a problem to call
627	it just in case after a fork. To make this easy, the function will fit in	649	it just in case after a fork.
628	quite nicely into a call to C<pthread_atfork>:
629		650
		651	Example: Automate calling C<ev_loop_fork> on the default loop when
		652	using pthreads.
		653
		654	static void
		655	post_fork_child (void)
		656	{
		657	ev_loop_fork (EV_DEFAULT);
		658	}
		659
		660	...
630	pthread_atfork (0, 0, ev_default_fork);	661	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		662
639	=item int ev_is_default_loop (loop)	663	=item int ev_is_default_loop (loop)
640		664
641	Returns true when the given loop is, in fact, the default loop, and false	665	Returns true when the given loop is, in fact, the default loop, and false
642	otherwise.	666	otherwise.
643		667
644	=item unsigned int ev_iteration (loop)	668	=item unsigned int ev_iteration (loop)
645		669
646	Returns the current iteration count for the loop, which is identical to	670	Returns the current iteration count for the event loop, which is identical
647	the number of times libev did poll for new events. It starts at C<0> and	671	to the number of times libev did poll for new events. It starts at C<0>
648	happily wraps around with enough iterations.	672	and happily wraps around with enough iterations.
649		673
650	This value can sometimes be useful as a generation counter of sorts (it	674	This value can sometimes be useful as a generation counter of sorts (it
651	"ticks" the number of loop iterations), as it roughly corresponds with	675	"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	676	C<ev_prepare> and C<ev_check> calls - and is incremented between the
653	prepare and check phases.	677	prepare and check phases.
654		678
655	=item unsigned int ev_depth (loop)	679	=item unsigned int ev_depth (loop)
656		680
657	Returns the number of times C<ev_loop> was entered minus the number of	681	Returns the number of times C<ev_run> was entered minus the number of
658	times C<ev_loop> was exited, in other words, the recursion depth.	682	times C<ev_run> was exited, in other words, the recursion depth.
659		683
660	Outside C<ev_loop>, this number is zero. In a callback, this number is	684	Outside C<ev_run>, this number is zero. In a callback, this number is
661	C<1>, unless C<ev_loop> was invoked recursively (or from another thread),	685	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
662	in which case it is higher.	686	in which case it is higher.
663		687
664	Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread	688	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	689	etc.), doesn't count as "exit" - consider this as a hint to avoid such
666	ungentleman behaviour unless it's really convenient.	690	ungentleman-like behaviour unless it's really convenient.
667		691
668	=item unsigned int ev_backend (loop)	692	=item unsigned int ev_backend (loop)
669		693
670	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	694	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
671	use.	695	use.
…		…
680		704
681	=item ev_now_update (loop)	705	=item ev_now_update (loop)
682		706
683	Establishes the current time by querying the kernel, updating the time	707	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	708	returned by C<ev_now ()> in the progress. This is a costly operation and
685	is usually done automatically within C<ev_loop ()>.	709	is usually done automatically within C<ev_run ()>.
686		710
687	This function is rarely useful, but when some event callback runs for a	711	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	712	very long time without entering the event loop, updating libev's idea of
689	the current time is a good idea.	713	the current time is a good idea.
690		714
…		…
692		716
693	=item ev_suspend (loop)	717	=item ev_suspend (loop)
694		718
695	=item ev_resume (loop)	719	=item ev_resume (loop)
696		720
697	These two functions suspend and resume a loop, for use when the loop is	721	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.	722	loop is not used for a while and timeouts should not be processed.
699		723
700	A typical use case would be an interactive program such as a game: When	724	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	725	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	726	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>	727	the program was suspended. This can be achieved by calling C<ev_suspend>
…		…
714	without a previous call to C<ev_suspend>.	738	without a previous call to C<ev_suspend>.
715		739
716	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the	740	Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
717	event loop time (see C<ev_now_update>).	741	event loop time (see C<ev_now_update>).
718		742
719	=item ev_loop (loop, int flags)	743	=item ev_run (loop, int flags)
720		744
721	Finally, this is it, the event handler. This function usually is called	745	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	746	after you have initialised all your watchers and you want to start
723	handling events.	747	handling events. It will ask the operating system for any new events, call
		748	the watcher callbacks, an then repeat the whole process indefinitely: This
		749	is why event loops are called I<loops>.
724		750
725	If the flags argument is specified as C<0>, it will not return until	751	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.	752	until either no event watchers are active anymore or C<ev_break> was
		753	called.
727		754
728	Please note that an explicit C<ev_unloop> is usually better than	755	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	756	relying on all watchers to be stopped when deciding when a program has
730	finished (especially in interactive programs), but having a program	757	finished (especially in interactive programs), but having a program
731	that automatically loops as long as it has to and no longer by virtue	758	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	759	of relying on its watchers stopping correctly, that is truly a thing of
733	beauty.	760	beauty.
734		761
735	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	762	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	763	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	764	block your process in case there are no events and will return after one
738	the loop.	765	iteration of the loop. This is sometimes useful to poll and handle new
		766	events while doing lengthy calculations, to keep the program responsive.
739		767
740	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	768	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	769	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	770	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	771	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	772	user-registered callback will be called), and will return after one
745	iteration of the loop.	773	iteration of the loop.
746		774
747	This is useful if you are waiting for some external event in conjunction	775	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	776	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	777	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.	778	usually a better approach for this kind of thing.
751		779
752	Here are the gory details of what C<ev_loop> does:	780	Here are the gory details of what C<ev_run> does:
753		781
		782	- Increment loop depth.
		783	- Reset the ev_break status.
754	- Before the first iteration, call any pending watchers.	784	- Before the first iteration, call any pending watchers.
		785	LOOP:
755	* If EVFLAG_FORKCHECK was used, check for a fork.	786	- If EVFLAG_FORKCHECK was used, check for a fork.
756	- If a fork was detected (by any means), queue and call all fork watchers.	787	- If a fork was detected (by any means), queue and call all fork watchers.
757	- Queue and call all prepare watchers.	788	- Queue and call all prepare watchers.
		789	- If ev_break was called, goto FINISH.
758	- If we have been forked, detach and recreate the kernel state	790	- If we have been forked, detach and recreate the kernel state
759	as to not disturb the other process.	791	as to not disturb the other process.
760	- Update the kernel state with all outstanding changes.	792	- Update the kernel state with all outstanding changes.
761	- Update the "event loop time" (ev_now ()).	793	- Update the "event loop time" (ev_now ()).
762	- Calculate for how long to sleep or block, if at all	794	- Calculate for how long to sleep or block, if at all
763	(active idle watchers, EVLOOP_NONBLOCK or not having	795	(active idle watchers, EVRUN_NOWAIT or not having
764	any active watchers at all will result in not sleeping).	796	any active watchers at all will result in not sleeping).
765	- Sleep if the I/O and timer collect interval say so.	797	- Sleep if the I/O and timer collect interval say so.
		798	- Increment loop iteration counter.
766	- Block the process, waiting for any events.	799	- Block the process, waiting for any events.
767	- Queue all outstanding I/O (fd) events.	800	- Queue all outstanding I/O (fd) events.
768	- Update the "event loop time" (ev_now ()), and do time jump adjustments.	801	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
769	- Queue all expired timers.	802	- Queue all expired timers.
770	- Queue all expired periodics.	803	- Queue all expired periodics.
771	- Unless any events are pending now, queue all idle watchers.	804	- Queue all idle watchers with priority higher than that of pending events.
772	- Queue all check watchers.	805	- Queue all check watchers.
773	- Call all queued watchers in reverse order (i.e. check watchers first).	806	- 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	807	Signals and child watchers are implemented as I/O watchers, and will
775	be handled here by queueing them when their watcher gets executed.	808	be handled here by queueing them when their watcher gets executed.
776	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	809	- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
777	were used, or there are no active watchers, return, otherwise	810	were used, or there are no active watchers, goto FINISH, otherwise
778	continue with step *.	811	continue with step LOOP.
		812	FINISH:
		813	- Reset the ev_break status iff it was EVBREAK_ONE.
		814	- Decrement the loop depth.
		815	- Return.
779		816
780	Example: Queue some jobs and then loop until no events are outstanding	817	Example: Queue some jobs and then loop until no events are outstanding
781	anymore.	818	anymore.
782		819
783	... queue jobs here, make sure they register event watchers as long	820	... 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..)	821	... as they still have work to do (even an idle watcher will do..)
785	ev_loop (my_loop, 0);	822	ev_run (my_loop, 0);
786	... jobs done or somebody called unloop. yeah!	823	... jobs done or somebody called unloop. yeah!
787		824
788	=item ev_unloop (loop, how)	825	=item ev_break (loop, how)
789		826
790	Can be used to make a call to C<ev_loop> return early (but only after it	827	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	828	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	829	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.	830	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
794		831
795	This "unloop state" will be cleared when entering C<ev_loop> again.	832	This "break state" will be cleared when entering C<ev_run> again.
796		833
797	It is safe to call C<ev_unloop> from outside any C<ev_loop> calls.	834	It is safe to call C<ev_break> from outside any C<ev_run> calls, too.
798		835
799	=item ev_ref (loop)	836	=item ev_ref (loop)
800		837
801	=item ev_unref (loop)	838	=item ev_unref (loop)
802		839
803	Ref/unref can be used to add or remove a reference count on the event	840	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	841	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.	842	count is nonzero, C<ev_run> will not return on its own.
806		843
807	This is useful when you have a watcher that you never intend to	844	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	845	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>	846	returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
810	before stopping it.	847	before stopping it.
811		848
812	As an example, libev itself uses this for its internal signal pipe: It	849	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	850	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	851	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	852	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	853	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	854	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	855	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>	856	(e.g. non-repeating timers) in which case you have to C<ev_ref>
820	in the callback).	857	in the callback).
821		858
822	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	859	Example: Create a signal watcher, but keep it from keeping C<ev_run>
823	running when nothing else is active.	860	running when nothing else is active.
824		861
825	ev_signal exitsig;	862	ev_signal exitsig;
826	ev_signal_init (&exitsig, sig_cb, SIGINT);	863	ev_signal_init (&exitsig, sig_cb, SIGINT);
827	ev_signal_start (loop, &exitsig);	864	ev_signal_start (loop, &exitsig);
…		…
890	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);	927	ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
891		928
892	=item ev_invoke_pending (loop)	929	=item ev_invoke_pending (loop)
893		930
894	This call will simply invoke all pending watchers while resetting their	931	This call will simply invoke all pending watchers while resetting their
895	pending state. Normally, C<ev_loop> does this automatically when required,	932	pending state. Normally, C<ev_run> does this automatically when required,
896	but when overriding the invoke callback this call comes handy.	933	but when overriding the invoke callback this call comes handy. This
		934	function can be invoked from a watcher - this can be useful for example
		935	when you want to do some lengthy calculation and want to pass further
		936	event handling to another thread (you still have to make sure only one
		937	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
897		938
898	=item int ev_pending_count (loop)	939	=item int ev_pending_count (loop)
899		940
900	Returns the number of pending watchers - zero indicates that no watchers	941	Returns the number of pending watchers - zero indicates that no watchers
901	are pending.	942	are pending.
902		943
903	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))	944	=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
904		945
905	This overrides the invoke pending functionality of the loop: Instead of	946	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	947	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	948	this callback instead. This is useful, for example, when you want to
908	invoke the actual watchers inside another context (another thread etc.).	949	invoke the actual watchers inside another context (another thread etc.).
909		950
910	If you want to reset the callback, use C<ev_invoke_pending> as new	951	If you want to reset the callback, use C<ev_invoke_pending> as new
911	callback.	952	callback.
…		…
914		955
915	Sometimes you want to share the same loop between multiple threads. This	956	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	957	can be done relatively simply by putting mutex_lock/unlock calls around
917	each call to a libev function.	958	each call to a libev function.
918		959
919	However, C<ev_loop> can run an indefinite time, so it is not feasible to	960	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	961	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>	962	loop via C<ev_break> and C<av_async_send>, another way is to set these
922	and I<acquire> callbacks on the loop.	963	I<release> and I<acquire> callbacks on the loop.
923		964
924	When set, then C<release> will be called just before the thread is	965	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	966	suspended waiting for new events, and C<acquire> is called just
926	afterwards.	967	afterwards.
927		968
…		…
930		971
931	While event loop modifications are allowed between invocations of	972	While event loop modifications are allowed between invocations of
932	C<release> and C<acquire> (that's their only purpose after all), no	973	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	974	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	975	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	976	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.	977	to take note of any changes you made.
937		978
938	In theory, threads executing C<ev_loop> will be async-cancel safe between	979	In theory, threads executing C<ev_run> will be async-cancel safe between
939	invocations of C<release> and C<acquire>.	980	invocations of C<release> and C<acquire>.
940		981
941	See also the locking example in the C<THREADS> section later in this	982	See also the locking example in the C<THREADS> section later in this
942	document.	983	document.
943		984
…		…
952	These two functions can be used to associate arbitrary data with a loop,	993	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	994	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	995	C<acquire> callbacks described above, but of course can be (ab-)used for
955	any other purpose as well.	996	any other purpose as well.
956		997
957	=item ev_loop_verify (loop)	998	=item ev_verify (loop)
958		999
959	This function only does something when C<EV_VERIFY> support has been	1000	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	1001	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	1002	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	1003	is found to be inconsistent, it will print an error message to standard
…		…
973		1014
974	In the following description, uppercase C<TYPE> in names stands for the	1015	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	1016	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.	1017	watchers and C<ev_io_start> for I/O watchers.
977		1018
978	A watcher is a structure that you create and register to record your	1019	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	1020	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:	1021	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1022	for that:
981		1023
982	static void my_cb (struct ev_loop loop, ev_io w, int revents)	1024	static void my_cb (struct ev_loop loop, ev_io w, int revents)
983	{	1025	{
984	ev_io_stop (w);	1026	ev_io_stop (w);
985	ev_unloop (loop, EVUNLOOP_ALL);	1027	ev_break (loop, EVBREAK_ALL);
986	}	1028	}
987		1029
988	struct ev_loop *loop = ev_default_loop (0);	1030	struct ev_loop *loop = ev_default_loop (0);
989		1031
990	ev_io stdin_watcher;	1032	ev_io stdin_watcher;
991		1033
992	ev_init (&stdin_watcher, my_cb);	1034	ev_init (&stdin_watcher, my_cb);
993	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	1035	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
994	ev_io_start (loop, &stdin_watcher);	1036	ev_io_start (loop, &stdin_watcher);
995		1037
996	ev_loop (loop, 0);	1038	ev_run (loop, 0);
997		1039
998	As you can see, you are responsible for allocating the memory for your	1040	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	1041	watcher structures (and it is I<usually> a bad idea to do this on the
1000	stack).	1042	stack).
1001		1043
1002	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1044	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).	1045	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1004		1046
1005	Each watcher structure must be initialised by a call to C<ev_init	1047	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	1048	*, 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	1049	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	1050	time the event loop detects that the file descriptor given is readable
1009	is readable and/or writable).	1051	and/or writable).
1010		1052
1011	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1053	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	1054	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<<	1055	is also a macro to combine initialisation and setting in one call: C<<
1014	ev_TYPE_init (watcher *, callback, ...) >>.	1056	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1065		1107
1066	=item C<EV_PREPARE>	1108	=item C<EV_PREPARE>
1067		1109
1068	=item C<EV_CHECK>	1110	=item C<EV_CHECK>
1069		1111
1070	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts	1112	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	1113	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	1114	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	1115	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	1116	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	1117	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
1076	C<ev_loop> from blocking).	1118	C<ev_run> from blocking).
1077		1119
1078	=item C<EV_EMBED>	1120	=item C<EV_EMBED>
1079		1121
1080	The embedded event loop specified in the C<ev_embed> watcher needs attention.	1122	The embedded event loop specified in the C<ev_embed> watcher needs attention.
1081		1123
1082	=item C<EV_FORK>	1124	=item C<EV_FORK>
1083		1125
1084	The event loop has been resumed in the child process after fork (see	1126	The event loop has been resumed in the child process after fork (see
1085	C<ev_fork>).	1127	C<ev_fork>).
		1128
		1129	=item C<EV_CLEANUP>
		1130
		1131	The event loop is about to be destroyed (see C<ev_cleanup>).
1086		1132
1087	=item C<EV_ASYNC>	1133	=item C<EV_ASYNC>
1088		1134
1089	The given async watcher has been asynchronously notified (see C<ev_async>).	1135	The given async watcher has been asynchronously notified (see C<ev_async>).
1090		1136
…		…
1262		1308
1263	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related	1309	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
1264	functions that do not need a watcher.	1310	functions that do not need a watcher.
1265		1311
1266	=back	1312	=back
1267
1268		1313
1269	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1314	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
1270		1315
1271	Each watcher has, by default, a member C<void *data> that you can change	1316	Each watcher has, by default, a member C<void *data> that you can change
1272	and read at any time: libev will completely ignore it. This can be used	1317	and read at any time: libev will completely ignore it. This can be used
…		…
1328	t2_cb (EV_P_ ev_timer *w, int revents)	1373	t2_cb (EV_P_ ev_timer *w, int revents)
1329	{	1374	{
1330	struct my_biggy big = (struct my_biggy *)	1375	struct my_biggy big = (struct my_biggy *)
1331	(((char *)w) - offsetof (struct my_biggy, t2));	1376	(((char *)w) - offsetof (struct my_biggy, t2));
1332	}	1377	}
		1378
		1379	=head2 WATCHER STATES
		1380
		1381	There are various watcher states mentioned throughout this manual -
		1382	active, pending and so on. In this section these states and the rules to
		1383	transition between them will be described in more detail - and while these
		1384	rules might look complicated, they usually do "the right thing".
		1385
		1386	=over 4
		1387
		1388	=item initialiased
		1389
		1390	Before a watcher can be registered with the event looop it has to be
		1391	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1392	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1393
		1394	In this state it is simply some block of memory that is suitable for use
		1395	in an event loop. It can be moved around, freed, reused etc. at will.
		1396
		1397	=item started/running/active
		1398
		1399	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1400	property of the event loop, and is actively waiting for events. While in
		1401	this state it cannot be accessed (except in a few documented ways), moved,
		1402	freed or anything else - the only legal thing is to keep a pointer to it,
		1403	and call libev functions on it that are documented to work on active watchers.
		1404
		1405	=item pending
		1406
		1407	If a watcher is active and libev determines that an event it is interested
		1408	in has occurred (such as a timer expiring), it will become pending. It will
		1409	stay in this pending state until either it is stopped or its callback is
		1410	about to be invoked, so it is not normally pending inside the watcher
		1411	callback.
		1412
		1413	The watcher might or might not be active while it is pending (for example,
		1414	an expired non-repeating timer can be pending but no longer active). If it
		1415	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1416	but it is still property of the event loop at this time, so cannot be
		1417	moved, freed or reused. And if it is active the rules described in the
		1418	previous item still apply.
		1419
		1420	It is also possible to feed an event on a watcher that is not active (e.g.
		1421	via C<ev_feed_event>), in which case it becomes pending without being
		1422	active.
		1423
		1424	=item stopped
		1425
		1426	A watcher can be stopped implicitly by libev (in which case it might still
		1427	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1428	latter will clear any pending state the watcher might be in, regardless
		1429	of whether it was active or not, so stopping a watcher explicitly before
		1430	freeing it is often a good idea.
		1431
		1432	While stopped (and not pending) the watcher is essentially in the
		1433	initialised state, that is it can be reused, moved, modified in any way
		1434	you wish.
		1435
		1436	=back
1333		1437
1334	=head2 WATCHER PRIORITY MODELS	1438	=head2 WATCHER PRIORITY MODELS
1335		1439
1336	Many event loops support I<watcher priorities>, which are usually small	1440	Many event loops support I<watcher priorities>, which are usually small
1337	integers that influence the ordering of event callback invocation	1441	integers that influence the ordering of event callback invocation
…		…
1622	...	1726	...
1623	struct ev_loop *loop = ev_default_init (0);	1727	struct ev_loop *loop = ev_default_init (0);
1624	ev_io stdin_readable;	1728	ev_io stdin_readable;
1625	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1729	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1626	ev_io_start (loop, &stdin_readable);	1730	ev_io_start (loop, &stdin_readable);
1627	ev_loop (loop, 0);	1731	ev_run (loop, 0);
1628		1732
1629		1733
1630	=head2 C<ev_timer> - relative and optionally repeating timeouts	1734	=head2 C<ev_timer> - relative and optionally repeating timeouts
1631		1735
1632	Timer watchers are simple relative timers that generate an event after a	1736	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	1745	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	1746	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	1747	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	1748	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	1749	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).	1750	no longer true when a callback calls C<ev_run> recursively).
1647		1751
1648	=head3 Be smart about timeouts	1752	=head3 Be smart about timeouts
1649		1753
1650	Many real-world problems involve some kind of timeout, usually for error	1754	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,	1755	recovery. A typical example is an HTTP request - if the other side hangs,
…		…
1822		1926
1823	=head3 The special problem of time updates	1927	=head3 The special problem of time updates
1824		1928
1825	Establishing the current time is a costly operation (it usually takes at	1929	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	1930	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	1931	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	1932	growing difference between C<ev_now ()> and C<ev_time ()> when handling
1829	lots of events in one iteration.	1933	lots of events in one iteration.
1830		1934
1831	The relative timeouts are calculated relative to the C<ev_now ()>	1935	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	1936	time. This is usually the right thing as this timestamp refers to the time
…		…
1949	}	2053	}
1950		2054
1951	ev_timer mytimer;	2055	ev_timer mytimer;
1952	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	2056	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1953	ev_timer_again (&mytimer); /* start timer */	2057	ev_timer_again (&mytimer); /* start timer */
1954	ev_loop (loop, 0);	2058	ev_run (loop, 0);
1955		2059
1956	// and in some piece of code that gets executed on any "activity":	2060	// and in some piece of code that gets executed on any "activity":
1957	// reset the timeout to start ticking again at 10 seconds	2061	// reset the timeout to start ticking again at 10 seconds
1958	ev_timer_again (&mytimer);	2062	ev_timer_again (&mytimer);
1959		2063
…		…
1985		2089
1986	As with timers, the callback is guaranteed to be invoked only when the	2090	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	2091	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	2092	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	2093	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).	2094	(but this is no longer true when a callback calls C<ev_run> recursively).
1991		2095
1992	=head3 Watcher-Specific Functions and Data Members	2096	=head3 Watcher-Specific Functions and Data Members
1993		2097
1994	=over 4	2098	=over 4
1995		2099
…		…
2156		2260
2157	=head2 C<ev_signal> - signal me when a signal gets signalled!	2261	=head2 C<ev_signal> - signal me when a signal gets signalled!
2158		2262
2159	Signal watchers will trigger an event when the process receives a specific	2263	Signal watchers will trigger an event when the process receives a specific
2160	signal one or more times. Even though signals are very asynchronous, libev	2264	signal one or more times. Even though signals are very asynchronous, libev
2161	will try it's best to deliver signals synchronously, i.e. as part of the	2265	will try its best to deliver signals synchronously, i.e. as part of the
2162	normal event processing, like any other event.	2266	normal event processing, like any other event.
2163		2267
2164	If you want signals to be delivered truly asynchronously, just use	2268	If you want signals to be delivered truly asynchronously, just use
2165	C<sigaction> as you would do without libev and forget about sharing	2269	C<sigaction> as you would do without libev and forget about sharing
2166	the signal. You can even use C<ev_async> from a signal handler to	2270	the signal. You can even use C<ev_async> from a signal handler to
…		…
2233	Example: Try to exit cleanly on SIGINT.	2337	Example: Try to exit cleanly on SIGINT.
2234		2338
2235	static void	2339	static void
2236	sigint_cb (struct ev_loop loop, ev_signal w, int revents)	2340	sigint_cb (struct ev_loop loop, ev_signal w, int revents)
2237	{	2341	{
2238	ev_unloop (loop, EVUNLOOP_ALL);	2342	ev_break (loop, EVBREAK_ALL);
2239	}	2343	}
2240		2344
2241	ev_signal signal_watcher;	2345	ev_signal signal_watcher;
2242	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	2346	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
2243	ev_signal_start (loop, &signal_watcher);	2347	ev_signal_start (loop, &signal_watcher);
…		…
2629		2733
2630	Prepare and check watchers are usually (but not always) used in pairs:	2734	Prepare and check watchers are usually (but not always) used in pairs:
2631	prepare watchers get invoked before the process blocks and check watchers	2735	prepare watchers get invoked before the process blocks and check watchers
2632	afterwards.	2736	afterwards.
2633		2737
2634	You I<must not> call C<ev_loop> or similar functions that enter	2738	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>	2739	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	2740	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	2741	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,	2742	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	2743	C<ev_check> so if you have one watcher of each kind they will always be
…		…
2807		2911
2808	if (timeout >= 0)	2912	if (timeout >= 0)
2809	// create/start timer	2913	// create/start timer
2810		2914
2811	// poll	2915	// poll
2812	ev_loop (EV_A_ 0);	2916	ev_run (EV_A_ 0);
2813		2917
2814	// stop timer again	2918	// stop timer again
2815	if (timeout >= 0)	2919	if (timeout >= 0)
2816	ev_timer_stop (EV_A_ &to);	2920	ev_timer_stop (EV_A_ &to);
2817		2921
…		…
2895	if you do not want that, you need to temporarily stop the embed watcher).	2999	if you do not want that, you need to temporarily stop the embed watcher).
2896		3000
2897	=item ev_embed_sweep (loop, ev_embed *)	3001	=item ev_embed_sweep (loop, ev_embed *)
2898		3002
2899	Make a single, non-blocking sweep over the embedded loop. This works	3003	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	3004	similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2901	appropriate way for embedded loops.	3005	appropriate way for embedded loops.
2902		3006
2903	=item struct ev_loop *other [read-only]	3007	=item struct ev_loop *other [read-only]
2904		3008
2905	The embedded event loop.	3009	The embedded event loop.
…		…
2991	disadvantage of having to use multiple event loops (which do not support	3095	disadvantage of having to use multiple event loops (which do not support
2992	signal watchers).	3096	signal watchers).
2993		3097
2994	When this is not possible, or you want to use the default loop for	3098	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	3099	other reasons, then in the process that wants to start "fresh", call
2996	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3100	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	3101	Destroying the default loop will "orphan" (not stop) all registered
2998	have to be careful not to execute code that modifies those watchers. Note	3102	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.	3103	those watchers. Note also that in that case, you have to re-register any
		3104	signal watchers.
3000		3105
3001	=head3 Watcher-Specific Functions and Data Members	3106	=head3 Watcher-Specific Functions and Data Members
3002		3107
3003	=over 4	3108	=over 4
3004		3109
3005	=item ev_fork_init (ev_signal *, callback)	3110	=item ev_fork_init (ev_fork *, callback)
3006		3111
3007	Initialises and configures the fork watcher - it has no parameters of any	3112	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,	3113	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3009	believe me.	3114	really.
3010		3115
3011	=back	3116	=back
3012		3117
3013		3118
		3119	=head2 C<ev_cleanup> - even the best things end
		3120
		3121	Cleanup watchers are called just before the event loop is being destroyed
		3122	by a call to C<ev_loop_destroy>.
		3123
		3124	While there is no guarantee that the event loop gets destroyed, cleanup
		3125	watchers provide a convenient method to install cleanup hooks for your
		3126	program, worker threads and so on - you just to make sure to destroy the
		3127	loop when you want them to be invoked.
		3128
		3129	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3130	all other watchers, they do not keep a reference to the event loop (which
		3131	makes a lot of sense if you think about it). Like all other watchers, you
		3132	can call libev functions in the callback, except C<ev_cleanup_start>.
		3133
		3134	=head3 Watcher-Specific Functions and Data Members
		3135
		3136	=over 4
		3137
		3138	=item ev_cleanup_init (ev_cleanup *, callback)
		3139
		3140	Initialises and configures the cleanup watcher - it has no parameters of
		3141	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3142	pointless, I assure you.
		3143
		3144	=back
		3145
		3146	Example: Register an atexit handler to destroy the default loop, so any
		3147	cleanup functions are called.
		3148
		3149	static void
		3150	program_exits (void)
		3151	{
		3152	ev_loop_destroy (EV_DEFAULT_UC);
		3153	}
		3154
		3155	...
		3156	atexit (program_exits);
		3157
		3158
3014	=head2 C<ev_async> - how to wake up an event loop	3159	=head2 C<ev_async> - how to wake up an event loop
3015		3160
3016	In general, you cannot use an C<ev_loop> from multiple threads or other	3161	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	3162	asynchronous sources such as signal handlers (as opposed to multiple event
3018	loops - those are of course safe to use in different threads).	3163	loops - those are of course safe to use in different threads).
3019		3164
3020	Sometimes, however, you need to wake up an event loop you do not control,	3165	Sometimes, however, you need to wake up an event loop you do not control,
3021	for example because it belongs to another thread. This is what C<ev_async>	3166	for example because it belongs to another thread. This is what C<ev_async>
…		…
3389	Associates a different C<struct ev_loop> with this watcher. You can only	3534	Associates a different C<struct ev_loop> with this watcher. You can only
3390	do this when the watcher is inactive (and not pending either).	3535	do this when the watcher is inactive (and not pending either).
3391		3536
3392	=item w->set ([arguments])	3537	=item w->set ([arguments])
3393		3538
3394	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be	3539	Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3395	called at least once. Unlike the C counterpart, an active watcher gets	3540	method or a suitable start method must be called at least once. Unlike the
3396	automatically stopped and restarted when reconfiguring it with this	3541	C counterpart, an active watcher gets automatically stopped and restarted
3397	method.	3542	when reconfiguring it with this method.
3398		3543
3399	=item w->start ()	3544	=item w->start ()
3400		3545
3401	Starts the watcher. Note that there is no C<loop> argument, as the	3546	Starts the watcher. Note that there is no C<loop> argument, as the
3402	constructor already stores the event loop.	3547	constructor already stores the event loop.
3403		3548
		3549	=item w->start ([arguments])
		3550
		3551	Instead of calling C<set> and C<start> methods separately, it is often
		3552	convenient to wrap them in one call. Uses the same type of arguments as
		3553	the configure C<set> method of the watcher.
		3554
3404	=item w->stop ()	3555	=item w->stop ()
3405		3556
3406	Stops the watcher if it is active. Again, no C<loop> argument.	3557	Stops the watcher if it is active. Again, no C<loop> argument.
3407		3558
3408	=item w->again () (C<ev::timer>, C<ev::periodic> only)	3559	=item w->again () (C<ev::timer>, C<ev::periodic> only)
…		…
3420		3571
3421	=back	3572	=back
3422		3573
3423	=back	3574	=back
3424		3575
3425	Example: Define a class with an IO and idle watcher, start one of them in	3576	Example: Define a class with two I/O and idle watchers, start the I/O
3426	the constructor.	3577	watchers in the constructor.
3427		3578
3428	class myclass	3579	class myclass
3429	{	3580	{
3430	ev::io io ; void io_cb (ev::io &w, int revents);	3581	ev::io io ; void io_cb (ev::io &w, int revents);
		3582	ev::io2 io2 ; void io2_cb (ev::io &w, int revents);
3431	ev::idle idle; void idle_cb (ev::idle &w, int revents);	3583	ev::idle idle; void idle_cb (ev::idle &w, int revents);
3432		3584
3433	myclass (int fd)	3585	myclass (int fd)
3434	{	3586	{
3435	io .set <myclass, &myclass::io_cb > (this);	3587	io .set <myclass, &myclass::io_cb > (this);
		3588	io2 .set <myclass, &myclass::io2_cb > (this);
3436	idle.set <myclass, &myclass::idle_cb> (this);	3589	idle.set <myclass, &myclass::idle_cb> (this);
3437		3590
3438	io.start (fd, ev::READ);	3591	io.set (fd, ev::WRITE); // configure the watcher
		3592	io.start (); // start it whenever convenient
		3593
		3594	io2.start (fd, ev::READ); // set + start in one call
3439	}	3595	}
3440	};	3596	};
3441		3597
3442		3598
3443	=head1 OTHER LANGUAGE BINDINGS	3599	=head1 OTHER LANGUAGE BINDINGS
…		…
3517	loop argument"). The C<EV_A> form is used when this is the sole argument,	3673	loop argument"). The C<EV_A> form is used when this is the sole argument,
3518	C<EV_A_> is used when other arguments are following. Example:	3674	C<EV_A_> is used when other arguments are following. Example:
3519		3675
3520	ev_unref (EV_A);	3676	ev_unref (EV_A);
3521	ev_timer_add (EV_A_ watcher);	3677	ev_timer_add (EV_A_ watcher);
3522	ev_loop (EV_A_ 0);	3678	ev_run (EV_A_ 0);
3523		3679
3524	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	3680	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3525	which is often provided by the following macro.	3681	which is often provided by the following macro.
3526		3682
3527	=item C<EV_P>, C<EV_P_>	3683	=item C<EV_P>, C<EV_P_>
…		…
3567	}	3723	}
3568		3724
3569	ev_check check;	3725	ev_check check;
3570	ev_check_init (&check, check_cb);	3726	ev_check_init (&check, check_cb);
3571	ev_check_start (EV_DEFAULT_ &check);	3727	ev_check_start (EV_DEFAULT_ &check);
3572	ev_loop (EV_DEFAULT_ 0);	3728	ev_run (EV_DEFAULT_ 0);
3573		3729
3574	=head1 EMBEDDING	3730	=head1 EMBEDDING
3575		3731
3576	Libev can (and often is) directly embedded into host	3732	Libev can (and often is) directly embedded into host
3577	applications. Examples of applications that embed it include the Deliantra	3733	applications. Examples of applications that embed it include the Deliantra
…		…
3668	to a compiled library. All other symbols change the ABI, which means all	3824	to a compiled library. All other symbols change the ABI, which means all
3669	users of libev and the libev code itself must be compiled with compatible	3825	users of libev and the libev code itself must be compiled with compatible
3670	settings.	3826	settings.
3671		3827
3672	=over 4	3828	=over 4
		3829
		3830	=item EV_COMPAT3 (h)
		3831
		3832	Backwards compatibility is a major concern for libev. This is why this
		3833	release of libev comes with wrappers for the functions and symbols that
		3834	have been renamed between libev version 3 and 4.
		3835
		3836	You can disable these wrappers (to test compatibility with future
		3837	versions) by defining C<EV_COMPAT3> to C<0> when compiling your
		3838	sources. This has the additional advantage that you can drop the C<struct>
		3839	from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
		3840	typedef in that case.
		3841
		3842	In some future version, the default for C<EV_COMPAT3> will become C<0>,
		3843	and in some even more future version the compatibility code will be
		3844	removed completely.
3673		3845
3674	=item EV_STANDALONE (h)	3846	=item EV_STANDALONE (h)
3675		3847
3676	Must always be C<1> if you do not use autoconf configuration, which	3848	Must always be C<1> if you do not use autoconf configuration, which
3677	keeps libev from including F<config.h>, and it also defines dummy	3849	keeps libev from including F<config.h>, and it also defines dummy
…		…
4027	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it	4199	The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4028	will be C<0>.	4200	will be C<0>.
4029		4201
4030	=item EV_VERIFY	4202	=item EV_VERIFY
4031		4203
4032	Controls how much internal verification (see C<ev_loop_verify ()>) will	4204	Controls how much internal verification (see C<ev_verify ()>) will
4033	be done: If set to C<0>, no internal verification code will be compiled	4205	be done: If set to C<0>, no internal verification code will be compiled
4034	in. If set to C<1>, then verification code will be compiled in, but not	4206	in. If set to C<1>, then verification code will be compiled in, but not
4035	called. If set to C<2>, then the internal verification code will be	4207	called. If set to C<2>, then the internal verification code will be
4036	called once per loop, which can slow down libev. If set to C<3>, then the	4208	called once per loop, which can slow down libev. If set to C<3>, then the
4037	verification code will be called very frequently, which will slow down	4209	verification code will be called very frequently, which will slow down
…		…
4252	userdata *u = ev_userdata (EV_A);	4424	userdata *u = ev_userdata (EV_A);
4253	pthread_mutex_lock (&u->lock);	4425	pthread_mutex_lock (&u->lock);
4254	}	4426	}
4255		4427
4256	The event loop thread first acquires the mutex, and then jumps straight	4428	The event loop thread first acquires the mutex, and then jumps straight
4257	into C<ev_loop>:	4429	into C<ev_run>:
4258		4430
4259	void *	4431	void *
4260	l_run (void *thr_arg)	4432	l_run (void *thr_arg)
4261	{	4433	{
4262	struct ev_loop loop = (struct ev_loop )thr_arg;	4434	struct ev_loop loop = (struct ev_loop )thr_arg;
4263		4435
4264	l_acquire (EV_A);	4436	l_acquire (EV_A);
4265	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);	4437	pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
4266	ev_loop (EV_A_ 0);	4438	ev_run (EV_A_ 0);
4267	l_release (EV_A);	4439	l_release (EV_A);
4268		4440
4269	return 0;	4441	return 0;
4270	}	4442	}
4271		4443
…		…
4323		4495
4324	=head3 COROUTINES	4496	=head3 COROUTINES
4325		4497
4326	Libev is very accommodating to coroutines ("cooperative threads"):	4498	Libev is very accommodating to coroutines ("cooperative threads"):
4327	libev fully supports nesting calls to its functions from different	4499	libev fully supports nesting calls to its functions from different
4328	coroutines (e.g. you can call C<ev_loop> on the same loop from two	4500	coroutines (e.g. you can call C<ev_run> on the same loop from two
4329	different coroutines, and switch freely between both coroutines running	4501	different coroutines, and switch freely between both coroutines running
4330	the loop, as long as you don't confuse yourself). The only exception is	4502	the loop, as long as you don't confuse yourself). The only exception is
4331	that you must not do this from C<ev_periodic> reschedule callbacks.	4503	that you must not do this from C<ev_periodic> reschedule callbacks.
4332		4504
4333	Care has been taken to ensure that libev does not keep local state inside	4505	Care has been taken to ensure that libev does not keep local state inside
4334	C<ev_loop>, and other calls do not usually allow for coroutine switches as	4506	C<ev_run>, and other calls do not usually allow for coroutine switches as
4335	they do not call any callbacks.	4507	they do not call any callbacks.
4336		4508
4337	=head2 COMPILER WARNINGS	4509	=head2 COMPILER WARNINGS
4338		4510
4339	Depending on your compiler and compiler settings, you might get no or a	4511	Depending on your compiler and compiler settings, you might get no or a
…		…
4423	=head3 C<kqueue> is buggy	4595	=head3 C<kqueue> is buggy
4424		4596
4425	The kqueue syscall is broken in all known versions - most versions support	4597	The kqueue syscall is broken in all known versions - most versions support
4426	only sockets, many support pipes.	4598	only sockets, many support pipes.
4427		4599
4428	Libev tries to work around this by not using C<kqueue> by default on	4600	Libev tries to work around this by not using C<kqueue> by default on this
4429	this rotten platform, but of course you can still ask for it when creating	4601	rotten platform, but of course you can still ask for it when creating a
4430	a loop.	4602	loop - embedding a socket-only kqueue loop into a select-based one is
		4603	probably going to work well.
4431		4604
4432	=head3 C<poll> is buggy	4605	=head3 C<poll> is buggy
4433		4606
4434	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>	4607	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
4435	implementation by something calling C<kqueue> internally around the 10.5.6	4608	implementation by something calling C<kqueue> internally around the 10.5.6
…		…
4454		4627
4455	=head3 C<errno> reentrancy	4628	=head3 C<errno> reentrancy
4456		4629
4457	The default compile environment on Solaris is unfortunately so	4630	The default compile environment on Solaris is unfortunately so
4458	thread-unsafe that you can't even use components/libraries compiled	4631	thread-unsafe that you can't even use components/libraries compiled
4459	without C<-D_REENTRANT> (as long as they use C<errno>), which, of course,	4632	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
4460	isn't defined by default.	4633	defined by default. A valid, if stupid, implementation choice.
4461		4634
4462	If you want to use libev in threaded environments you have to make sure	4635	If you want to use libev in threaded environments you have to make sure
4463	it's compiled with C<_REENTRANT> defined.	4636	it's compiled with C<_REENTRANT> defined.
4464		4637
4465	=head3 Event port backend	4638	=head3 Event port backend
4466		4639
4467	The scalable event interface for Solaris is called "event ports". Unfortunately,	4640	The scalable event interface for Solaris is called "event
4468	this mechanism is very buggy. If you run into high CPU usage, your program	4641	ports". Unfortunately, this mechanism is very buggy in all major
		4642	releases. If you run into high CPU usage, your program freezes or you get
4469	freezes or you get a large number of spurious wakeups, make sure you have	4643	a large number of spurious wakeups, make sure you have all the relevant
4470	all the relevant and latest kernel patches applied. No, I don't know which	4644	and latest kernel patches applied. No, I don't know which ones, but there
4471	ones, but there are multiple ones.	4645	are multiple ones to apply, and afterwards, event ports actually work
		4646	great.
4472		4647
4473	If you can't get it to work, you can try running the program by setting	4648	If you can't get it to work, you can try running the program by setting
4474	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and	4649	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
4475	C<select> backends.	4650	C<select> backends.
4476		4651
4477	=head2 AIX POLL BUG	4652	=head2 AIX POLL BUG
4478		4653
4479	AIX unfortunately has a broken C<poll.h> header. Libev works around	4654	AIX unfortunately has a broken C<poll.h> header. Libev works around
4480	this by trying to avoid the poll backend altogether (i.e. it's not even	4655	this by trying to avoid the poll backend altogether (i.e. it's not even
4481	compiled in), which normally isn't a big problem as C<select> works fine	4656	compiled in), which normally isn't a big problem as C<select> works fine
4482	with large bitsets, and AIX is dead anyway.	4657	with large bitsets on AIX, and AIX is dead anyway.
4483		4658
4484	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4659	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
4485		4660
4486	=head3 General issues	4661	=head3 General issues
4487		4662
…		…
4593	structure (guaranteed by POSIX but not by ISO C for example), but it also	4768	structure (guaranteed by POSIX but not by ISO C for example), but it also
4594	assumes that the same (machine) code can be used to call any watcher	4769	assumes that the same (machine) code can be used to call any watcher
4595	callback: The watcher callbacks have different type signatures, but libev	4770	callback: The watcher callbacks have different type signatures, but libev
4596	calls them using an C<ev_watcher *> internally.	4771	calls them using an C<ev_watcher *> internally.
4597		4772
		4773	=item pointer accesses must be thread-atomic
		4774
		4775	Accessing a pointer value must be atomic, it must both be readable and
		4776	writable in one piece - this is the case on all current architectures.
		4777
4598	=item C<sig_atomic_t volatile> must be thread-atomic as well	4778	=item C<sig_atomic_t volatile> must be thread-atomic as well
4599		4779
4600	The type C<sig_atomic_t volatile> (or whatever is defined as	4780	The type C<sig_atomic_t volatile> (or whatever is defined as
4601	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different	4781	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
4602	threads. This is not part of the specification for C<sig_atomic_t>, but is	4782	threads. This is not part of the specification for C<sig_atomic_t>, but is
…		…
4624	watchers.	4804	watchers.
4625		4805
4626	=item C<double> must hold a time value in seconds with enough accuracy	4806	=item C<double> must hold a time value in seconds with enough accuracy
4627		4807
4628	The type C<double> is used to represent timestamps. It is required to	4808	The type C<double> is used to represent timestamps. It is required to
4629	have at least 51 bits of mantissa (and 9 bits of exponent), which is good	4809	have at least 51 bits of mantissa (and 9 bits of exponent), which is
4630	enough for at least into the year 4000. This requirement is fulfilled by	4810	good enough for at least into the year 4000 with millisecond accuracy
		4811	(the design goal for libev). This requirement is overfulfilled by
4631	implementations implementing IEEE 754, which is basically all existing	4812	implementations using IEEE 754, which is basically all existing ones. With
4632	ones. With IEEE 754 doubles, you get microsecond accuracy until at least	4813	IEEE 754 doubles, you get microsecond accuracy until at least 2200.
4633	2200.
4634		4814
4635	=back	4815	=back
4636		4816
4637	If you know of other additional requirements drop me a note.	4817	If you know of other additional requirements drop me a note.
4638		4818
…		…
4708	=back	4888	=back
4709		4889
4710		4890
4711	=head1 PORTING FROM LIBEV 3.X TO 4.X	4891	=head1 PORTING FROM LIBEV 3.X TO 4.X
4712		4892
4713	The major version 4 introduced some minor incompatible changes to the API.	4893	The major version 4 introduced some incompatible changes to the API.
4714		4894
4715	At the moment, the C<ev.h> header file tries to implement superficial	4895	At the moment, the C<ev.h> header file provides compatibility definitions
4716	compatibility, so most programs should still compile. Those might be	4896	for all changes, so most programs should still compile. The compatibility
4717	removed in later versions of libev, so better update early than late.	4897	layer might be removed in later versions of libev, so better update to the
		4898	new API early than late.
4718		4899
4719	=over 4	4900	=over 4
4720		4901
4721	=item C<ev_loop_count> renamed to C<ev_iteration>	4902	=item C<EV_COMPAT3> backwards compatibility mechanism
4722		4903
4723	=item C<ev_loop_depth> renamed to C<ev_depth>	4904	The backward compatibility mechanism can be controlled by
		4905	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4906	section.
4724		4907
4725	=item C<ev_loop_verify> renamed to C<ev_verify>	4908	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4909
		4910	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4911
		4912	ev_loop_destroy (EV_DEFAULT_UC);
		4913	ev_loop_fork (EV_DEFAULT);
		4914
		4915	=item function/symbol renames
		4916
		4917	A number of functions and symbols have been renamed:
		4918
		4919	ev_loop => ev_run
		4920	EVLOOP_NONBLOCK => EVRUN_NOWAIT
		4921	EVLOOP_ONESHOT => EVRUN_ONCE
		4922
		4923	ev_unloop => ev_break
		4924	EVUNLOOP_CANCEL => EVBREAK_CANCEL
		4925	EVUNLOOP_ONE => EVBREAK_ONE
		4926	EVUNLOOP_ALL => EVBREAK_ALL
		4927
		4928	EV_TIMEOUT => EV_TIMER
		4929
		4930	ev_loop_count => ev_iteration
		4931	ev_loop_depth => ev_depth
		4932	ev_loop_verify => ev_verify
4726		4933
4727	Most functions working on C<struct ev_loop> objects don't have an	4934	Most functions working on C<struct ev_loop> objects don't have an
4728	C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is	4935	C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
		4936	associated constants have been renamed to not collide with the C<struct
		4937	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
		4938	as all other watcher types. Note that C<ev_loop_fork> is still called
4729	still called C<ev_loop_fork> because it would otherwise clash with the	4939	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4730	C<ev_fork> typedef.	4940	typedef.
4731
4732	=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>
4733
4734	This is a simple rename - all other watcher types use their name
4735	as revents flag, and now C<ev_timer> does, too.
4736
4737	Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4738	and continue to be present for the foreseeable future, so this is mostly a
4739	documentation change.
4740		4941
4741	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4942	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4742		4943
4743	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4944	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4744	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4945	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
…		…
4751		4952
4752	=over 4	4953	=over 4
4753		4954
4754	=item active	4955	=item active
4755		4956
4756	A watcher is active as long as it has been started (has been attached to	4957	A watcher is active as long as it has been started and not yet stopped.
4757	an event loop) but not yet stopped (disassociated from the event loop).	4958	See L<WATCHER STATES> for details.
4758		4959
4759	=item application	4960	=item application
4760		4961
4761	In this document, an application is whatever is using libev.	4962	In this document, an application is whatever is using libev.
		4963
		4964	=item backend
		4965
		4966	The part of the code dealing with the operating system interfaces.
4762		4967
4763	=item callback	4968	=item callback
4764		4969
4765	The address of a function that is called when some event has been	4970	The address of a function that is called when some event has been
4766	detected. Callbacks are being passed the event loop, the watcher that	4971	detected. Callbacks are being passed the event loop, the watcher that
4767	received the event, and the actual event bitset.	4972	received the event, and the actual event bitset.
4768		4973
4769	=item callback invocation	4974	=item callback/watcher invocation
4770		4975
4771	The act of calling the callback associated with a watcher.	4976	The act of calling the callback associated with a watcher.
4772		4977
4773	=item event	4978	=item event
4774		4979
…		…
4793	The model used to describe how an event loop handles and processes	4998	The model used to describe how an event loop handles and processes
4794	watchers and events.	4999	watchers and events.
4795		5000
4796	=item pending	5001	=item pending
4797		5002
4798	A watcher is pending as soon as the corresponding event has been detected,	5003	A watcher is pending as soon as the corresponding event has been
4799	and stops being pending as soon as the watcher will be invoked or its	5004	detected. See L<WATCHER STATES> for details.
4800	pending status is explicitly cleared by the application.
4801
4802	A watcher can be pending, but not active. Stopping a watcher also clears
4803	its pending status.
4804		5005
4805	=item real time	5006	=item real time
4806		5007
4807	The physical time that is observed. It is apparently strictly monotonic :)	5008	The physical time that is observed. It is apparently strictly monotonic :)
4808		5009
…		…
4815	=item watcher	5016	=item watcher
4816		5017
4817	A data structure that describes interest in certain events. Watchers need	5018	A data structure that describes interest in certain events. Watchers need
4818	to be started (attached to an event loop) before they can receive events.	5019	to be started (attached to an event loop) before they can receive events.
4819		5020
4820	=item watcher invocation
4821
4822	The act of calling the callback associated with a watcher.
4823
4824	=back	5021	=back
4825		5022
4826	=head1 AUTHOR	5023	=head1 AUTHOR
4827		5024
4828	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5025	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
		5026	Magnusson and Emanuele Giaquinta.
4829		5027

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Comparing libev/ev.pod (file contents): Revision 1.305 by root, Thu Oct 14 05:07:04 2010 UTC vs. Revision 1.340 by root, Wed Nov 3 20:03:21 2010 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.305 by root, Thu Oct 14 05:07:04 2010 UTC vs.
Revision 1.340 by root, Wed Nov 3 20:03:21 2010 UTC