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

Comparing libev/ev.pod (file contents):
Revision 1.319 by root, Fri Oct 22 10:09:12 2010 UTC vs.
Revision 1.349 by root, Mon Jan 10 01:58:55 2011 UTC

…		…
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);
…		…
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
…		…
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. Also interetsing is the combination of	178	you actually want to know. Also interesting is the combination of
171	C<ev_update_now> and C<ev_now>.	179	C<ev_update_now> and C<ev_now>.
172		180
173	=item ev_sleep (ev_tstamp interval)	181	=item ev_sleep (ev_tstamp interval)
174		182
175	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
…		…
193	as this indicates an incompatible change. Minor versions are usually	201	as this indicates an incompatible change. Minor versions are usually
194	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
195	not a problem.	203	not a problem.
196		204
197	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
198	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).
199		208
200	assert (("libev version mismatch",	209	assert (("libev version mismatch",
201	ev_version_major () == EV_VERSION_MAJOR	210	ev_version_major () == EV_VERSION_MAJOR
202	&& ev_version_minor () >= EV_VERSION_MINOR));	211	&& ev_version_minor () >= EV_VERSION_MINOR));
203		212
…		…
232	the current system, you would need to look at C<ev_embeddable_backends ()	241	the current system, you would need to look at C<ev_embeddable_backends ()
233	& ev_supported_backends ()>, likewise for recommended ones.	242	& ev_supported_backends ()>, likewise for recommended ones.
234		243
235	See the description of C<ev_embed> watchers for more info.	244	See the description of C<ev_embed> watchers for more info.
236		245
237	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]	246	=item ev_set_allocator (void (cb)(void *ptr, long size))
238		247
239	Sets the allocation function to use (the prototype is similar - the	248	Sets the allocation function to use (the prototype is similar - the
240	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
241	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
242	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
…		…
268	}	277	}
269		278
270	...	279	...
271	ev_set_allocator (persistent_realloc);	280	ev_set_allocator (persistent_realloc);
272		281
273	=item ev_set_syserr_cb (void (cb)(const char msg)); [NOT REENTRANT]	282	=item ev_set_syserr_cb (void (cb)(const char msg))
274		283
275	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
276	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
277	indicating the system call or subsystem causing the problem. If this	286	indicating the system call or subsystem causing the problem. If this
278	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	}	299	}
291		300
292	...	301	...
293	ev_set_syserr_cb (fatal_error);	302	ev_set_syserr_cb (fatal_error);
294		303
		304	=item ev_feed_signal (int signum)
		305
		306	This function can be used to "simulate" a signal receive. It is completely
		307	safe to call this function at any time, from any context, including signal
		308	handlers or random threads.
		309
		310	It's main use is to customise signal handling in your process, especially
		311	in the presence of threads. For example, you could block signals
		312	by default in all threads (and specifying C<EVFLAG_NOSIGMASK> when
		313	creating any loops), and in one thread, use C<sigwait> or any other
		314	mechanism to wait for signals, then "deliver" them to libev by calling
		315	C<ev_feed_signal>.
		316
295	=back	317	=back
296		318
297	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	319	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
298		320
299	An event loop is described by a C<struct ev_loop *> (the C<struct> is	321	An event loop is described by a C<struct ev_loop *> (the C<struct> is
300	I<not> optional in this case unless libev 3 compatibility is disabled, as	322	I<not> optional in this case unless libev 3 compatibility is disabled, as
301	libev 3 had an C<ev_loop> function colliding with the struct name).	323	libev 3 had an C<ev_loop> function colliding with the struct name).
302		324
303	The library knows two types of such loops, the I<default> loop, which	325	The library knows two types of such loops, the I<default> loop, which
304	supports signals and child events, and dynamically created event loops	326	supports child process events, and dynamically created event loops which
305	which do not.	327	do not.
306		328
307	=over 4	329	=over 4
308		330
309	=item struct ev_loop *ev_default_loop (unsigned int flags)	331	=item struct ev_loop *ev_default_loop (unsigned int flags)
310		332
311	This will initialise the default event loop if it hasn't been initialised	333	This returns the "default" event loop object, which is what you should
312	yet and return it. If the default loop could not be initialised, returns	334	normally use when you just need "the event loop". Event loop objects and
313	false. If it already was initialised it simply returns it (and ignores the	335	the C<flags> parameter are described in more detail in the entry for
314	flags. If that is troubling you, check C<ev_backend ()> afterwards).	336	C<ev_loop_new>.
		337
		338	If the default loop is already initialised then this function simply
		339	returns it (and ignores the flags. If that is troubling you, check
		340	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		341	flags, which should almost always be C<0>, unless the caller is also the
		342	one calling C<ev_run> or otherwise qualifies as "the main program".
315		343
316	If you don't know what event loop to use, use the one returned from this	344	If you don't know what event loop to use, use the one returned from this
317	function.	345	function (or via the C<EV_DEFAULT> macro).
318		346
319	Note that this function is I<not> thread-safe, so if you want to use it	347	Note that this function is I<not> thread-safe, so if you want to use it
320	from multiple threads, you have to lock (note also that this is unlikely,	348	from multiple threads, you have to employ some kind of mutex (note also
321	as loops cannot be shared easily between threads anyway).	349	that this case is unlikely, as loops cannot be shared easily between
		350	threads anyway).
322		351
323	The default loop is the only loop that can handle C<ev_signal> and	352	The default loop is the only loop that can handle C<ev_child> watchers,
324	C<ev_child> watchers, and to do this, it always registers a handler	353	and to do this, it always registers a handler for C<SIGCHLD>. If this is
325	for C<SIGCHLD>. If this is a problem for your application you can either	354	a problem for your application you can either create a dynamic loop with
326	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	355	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
327	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	356	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
328	C<ev_default_init>.	357
		358	Example: This is the most typical usage.
		359
		360	if (!ev_default_loop (0))
		361	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		362
		363	Example: Restrict libev to the select and poll backends, and do not allow
		364	environment settings to be taken into account:
		365
		366	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
		367
		368	=item struct ev_loop *ev_loop_new (unsigned int flags)
		369
		370	This will create and initialise a new event loop object. If the loop
		371	could not be initialised, returns false.
		372
		373	This function is thread-safe, and one common way to use libev with
		374	threads is indeed to create one loop per thread, and using the default
		375	loop in the "main" or "initial" thread.
329		376
330	The flags argument can be used to specify special behaviour or specific	377	The flags argument can be used to specify special behaviour or specific
331	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	378	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
332		379
333	The following flags are supported:	380	The following flags are supported:
…		…
368	environment variable.	415	environment variable.
369		416
370	=item C<EVFLAG_NOINOTIFY>	417	=item C<EVFLAG_NOINOTIFY>
371		418
372	When this flag is specified, then libev will not attempt to use the	419	When this flag is specified, then libev will not attempt to use the
373	I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and	420	I<inotify> API for its C<ev_stat> watchers. Apart from debugging and
374	testing, this flag can be useful to conserve inotify file descriptors, as	421	testing, this flag can be useful to conserve inotify file descriptors, as
375	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.	422	otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
376		423
377	=item C<EVFLAG_SIGNALFD>	424	=item C<EVFLAG_SIGNALFD>
378		425
379	When this flag is specified, then libev will attempt to use the	426	When this flag is specified, then libev will attempt to use the
380	I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API	427	I<signalfd> API for its C<ev_signal> (and C<ev_child>) watchers. This API
381	delivers signals synchronously, which makes it both faster and might make	428	delivers signals synchronously, which makes it both faster and might make
382	it possible to get the queued signal data. It can also simplify signal	429	it possible to get the queued signal data. It can also simplify signal
383	handling with threads, as long as you properly block signals in your	430	handling with threads, as long as you properly block signals in your
384	threads that are not interested in handling them.	431	threads that are not interested in handling them.
385		432
386	Signalfd will not be used by default as this changes your signal mask, and	433	Signalfd will not be used by default as this changes your signal mask, and
387	there are a lot of shoddy libraries and programs (glib's threadpool for	434	there are a lot of shoddy libraries and programs (glib's threadpool for
388	example) that can't properly initialise their signal masks.	435	example) that can't properly initialise their signal masks.
		436
		437	=item C<EVFLAG_NOSIGMASK>
		438
		439	When this flag is specified, then libev will avoid to modify the signal
		440	mask. Specifically, this means you ahve to make sure signals are unblocked
		441	when you want to receive them.
		442
		443	This behaviour is useful when you want to do your own signal handling, or
		444	want to handle signals only in specific threads and want to avoid libev
		445	unblocking the signals.
		446
		447	This flag's behaviour will become the default in future versions of libev.
389		448
390	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	449	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
391		450
392	This is your standard select(2) backend. Not I<completely> standard, as	451	This is your standard select(2) backend. Not I<completely> standard, as
393	libev tries to roll its own fd_set with no limits on the number of fds,	452	libev tries to roll its own fd_set with no limits on the number of fds,
…		…
429	epoll scales either O(1) or O(active_fds).	488	epoll scales either O(1) or O(active_fds).
430		489
431	The epoll mechanism deserves honorable mention as the most misdesigned	490	The epoll mechanism deserves honorable mention as the most misdesigned
432	of the more advanced event mechanisms: mere annoyances include silently	491	of the more advanced event mechanisms: mere annoyances include silently
433	dropping file descriptors, requiring a system call per change per file	492	dropping file descriptors, requiring a system call per change per file
434	descriptor (and unnecessary guessing of parameters), problems with dup and	493	descriptor (and unnecessary guessing of parameters), problems with dup,
		494	returning before the timeout value, resulting in additional iterations
		495	(and only giving 5ms accuracy while select on the same platform gives
435	so on. The biggest issue is fork races, however - if a program forks then	496	0.1ms) and so on. The biggest issue is fork races, however - if a program
436	I<both> parent and child process have to recreate the epoll set, which can	497	forks then I<both> parent and child process have to recreate the epoll
437	take considerable time (one syscall per file descriptor) and is of course	498	set, which can take considerable time (one syscall per file descriptor)
438	hard to detect.	499	and is of course hard to detect.
439		500
440	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but	501	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but
441	of course I<doesn't>, and epoll just loves to report events for totally	502	of course I<doesn't>, and epoll just loves to report events for totally
442	I<different> file descriptors (even already closed ones, so one cannot	503	I<different> file descriptors (even already closed ones, so one cannot
443	even remove them from the set) than registered in the set (especially	504	even remove them from the set) than registered in the set (especially
…		…
445	employing an additional generation counter and comparing that against the	506	employing an additional generation counter and comparing that against the
446	events to filter out spurious ones, recreating the set when required. Last	507	events to filter out spurious ones, recreating the set when required. Last
447	not least, it also refuses to work with some file descriptors which work	508	not least, it also refuses to work with some file descriptors which work
448	perfectly fine with C<select> (files, many character devices...).	509	perfectly fine with C<select> (files, many character devices...).
449		510
		511	Epoll is truly the train wreck analog among event poll mechanisms.
		512
450	While stopping, setting and starting an I/O watcher in the same iteration	513	While stopping, setting and starting an I/O watcher in the same iteration
451	will result in some caching, there is still a system call per such	514	will result in some caching, there is still a system call per such
452	incident (because the same I<file descriptor> could point to a different	515	incident (because the same I<file descriptor> could point to a different
453	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed	516	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
454	file descriptors might not work very well if you register events for both	517	file descriptors might not work very well if you register events for both
…		…
542		605
543	Try all backends (even potentially broken ones that wouldn't be tried	606	Try all backends (even potentially broken ones that wouldn't be tried
544	with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as	607	with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as
545	C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.	608	C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.
546		609
547	It is definitely not recommended to use this flag.	610	It is definitely not recommended to use this flag, use whatever
		611	C<ev_recommended_backends ()> returns, or simply do not specify a backend
		612	at all.
		613
		614	=item C<EVBACKEND_MASK>
		615
		616	Not a backend at all, but a mask to select all backend bits from a
		617	C<flags> value, in case you want to mask out any backends from a flags
		618	value (e.g. when modifying the C<LIBEV_FLAGS> environment variable).
548		619
549	=back	620	=back
550		621
551	If one or more of the backend flags are or'ed into the flags value,	622	If one or more of the backend flags are or'ed into the flags value,
552	then only these backends will be tried (in the reverse order as listed	623	then only these backends will be tried (in the reverse order as listed
553	here). If none are specified, all backends in C<ev_recommended_backends	624	here). If none are specified, all backends in C<ev_recommended_backends
554	()> will be tried.	625	()> will be tried.
555		626
556	Example: This is the most typical usage.
557
558	if (!ev_default_loop (0))
559	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
560
561	Example: Restrict libev to the select and poll backends, and do not allow
562	environment settings to be taken into account:
563
564	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
565
566	Example: Use whatever libev has to offer, but make sure that kqueue is
567	used if available (warning, breaks stuff, best use only with your own
568	private event loop and only if you know the OS supports your types of
569	fds):
570
571	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);
572
573	=item struct ev_loop *ev_loop_new (unsigned int flags)
574
575	Similar to C<ev_default_loop>, but always creates a new event loop that is
576	always distinct from the default loop.
577
578	Note that this function I<is> thread-safe, and one common way to use
579	libev with threads is indeed to create one loop per thread, and using the
580	default loop in the "main" or "initial" thread.
581
582	Example: Try to create a event loop that uses epoll and nothing else.	627	Example: Try to create a event loop that uses epoll and nothing else.
583		628
584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	629	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
585	if (!epoller)	630	if (!epoller)
586	fatal ("no epoll found here, maybe it hides under your chair");	631	fatal ("no epoll found here, maybe it hides under your chair");
587		632
		633	Example: Use whatever libev has to offer, but make sure that kqueue is
		634	used if available.
		635
		636	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () \| EVBACKEND_KQUEUE);
		637
588	=item ev_default_destroy ()	638	=item ev_loop_destroy (loop)
589		639
590	Destroys the default loop (frees all memory and kernel state etc.). None	640	Destroys an event loop object (frees all memory and kernel state
591	of the active event watchers will be stopped in the normal sense, so	641	etc.). None of the active event watchers will be stopped in the normal
592	e.g. C<ev_is_active> might still return true. It is your responsibility to	642	sense, so e.g. C<ev_is_active> might still return true. It is your
593	either stop all watchers cleanly yourself I<before> calling this function,	643	responsibility to either stop all watchers cleanly yourself I<before>
594	or cope with the fact afterwards (which is usually the easiest thing, you	644	calling this function, or cope with the fact afterwards (which is usually
595	can just ignore the watchers and/or C<free ()> them for example).	645	the easiest thing, you can just ignore the watchers and/or C<free ()> them
		646	for example).
596		647
597	Note that certain global state, such as signal state (and installed signal	648	Note that certain global state, such as signal state (and installed signal
598	handlers), will not be freed by this function, and related watchers (such	649	handlers), will not be freed by this function, and related watchers (such
599	as signal and child watchers) would need to be stopped manually.	650	as signal and child watchers) would need to be stopped manually.
600		651
601	In general it is not advisable to call this function except in the	652	This function is normally used on loop objects allocated by
602	rare occasion where you really need to free e.g. the signal handling	653	C<ev_loop_new>, but it can also be used on the default loop returned by
		654	C<ev_default_loop>, in which case it is not thread-safe.
		655
		656	Note that it is not advisable to call this function on the default loop
		657	except in the rare occasion where you really need to free its resources.
603	pipe fds. If you need dynamically allocated loops it is better to use	658	If you need dynamically allocated loops it is better to use C<ev_loop_new>
604	C<ev_loop_new> and C<ev_loop_destroy>.	659	and C<ev_loop_destroy>.
605		660
606	=item ev_loop_destroy (loop)	661	=item ev_loop_fork (loop)
607		662
608	Like C<ev_default_destroy>, but destroys an event loop created by an
609	earlier call to C<ev_loop_new>.
610
611	=item ev_default_fork ()
612
613	This function sets a flag that causes subsequent C<ev_run> iterations	663	This function sets a flag that causes subsequent C<ev_run> iterations to
614	to reinitialise the kernel state for backends that have one. Despite the	664	reinitialise the kernel state for backends that have one. Despite the
615	name, you can call it anytime, but it makes most sense after forking, in	665	name, you can call it anytime, but it makes most sense after forking, in
616	the child process (or both child and parent, but that again makes little	666	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
617	sense). You I<must> call it in the child before using any of the libev	667	child before resuming or calling C<ev_run>.
618	functions, and it will only take effect at the next C<ev_run> iteration.
619		668
620	Again, you I<have> to call it on I<any> loop that you want to re-use after	669	Again, you I<have> to call it on I<any> loop that you want to re-use after
621	a fork, I<even if you do not plan to use the loop in the parent>. This is	670	a fork, I<even if you do not plan to use the loop in the parent>. This is
622	because some kernel interfaces cough I<kqueue> cough do funny things	671	because some kernel interfaces cough I<kqueue> cough do funny things
623	during fork.	672	during fork.
…		…
628	call it at all (in fact, C<epoll> is so badly broken that it makes a	677	call it at all (in fact, C<epoll> is so badly broken that it makes a
629	difference, but libev will usually detect this case on its own and do a	678	difference, but libev will usually detect this case on its own and do a
630	costly reset of the backend).	679	costly reset of the backend).
631		680
632	The function itself is quite fast and it's usually not a problem to call	681	The function itself is quite fast and it's usually not a problem to call
633	it just in case after a fork. To make this easy, the function will fit in	682	it just in case after a fork.
634	quite nicely into a call to C<pthread_atfork>:
635		683
		684	Example: Automate calling C<ev_loop_fork> on the default loop when
		685	using pthreads.
		686
		687	static void
		688	post_fork_child (void)
		689	{
		690	ev_loop_fork (EV_DEFAULT);
		691	}
		692
		693	...
636	pthread_atfork (0, 0, ev_default_fork);	694	pthread_atfork (0, 0, post_fork_child);
637
638	=item ev_loop_fork (loop)
639
640	Like C<ev_default_fork>, but acts on an event loop created by
641	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
642	after fork that you want to re-use in the child, and how you keep track of
643	them is entirely your own problem.
644		695
645	=item int ev_is_default_loop (loop)	696	=item int ev_is_default_loop (loop)
646		697
647	Returns true when the given loop is, in fact, the default loop, and false	698	Returns true when the given loop is, in fact, the default loop, and false
648	otherwise.	699	otherwise.
…		…
659	prepare and check phases.	710	prepare and check phases.
660		711
661	=item unsigned int ev_depth (loop)	712	=item unsigned int ev_depth (loop)
662		713
663	Returns the number of times C<ev_run> was entered minus the number of	714	Returns the number of times C<ev_run> was entered minus the number of
664	times C<ev_run> was exited, in other words, the recursion depth.	715	times C<ev_run> was exited normally, in other words, the recursion depth.
665		716
666	Outside C<ev_run>, this number is zero. In a callback, this number is	717	Outside C<ev_run>, this number is zero. In a callback, this number is
667	C<1>, unless C<ev_run> was invoked recursively (or from another thread),	718	C<1>, unless C<ev_run> was invoked recursively (or from another thread),
668	in which case it is higher.	719	in which case it is higher.
669		720
670	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread	721	Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread,
671	etc.), doesn't count as "exit" - consider this as a hint to avoid such	722	throwing an exception etc.), doesn't count as "exit" - consider this
672	ungentleman-like behaviour unless it's really convenient.	723	as a hint to avoid such ungentleman-like behaviour unless it's really
		724	convenient, in which case it is fully supported.
673		725
674	=item unsigned int ev_backend (loop)	726	=item unsigned int ev_backend (loop)
675		727
676	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	728	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
677	use.	729	use.
…		…
738	relying on all watchers to be stopped when deciding when a program has	790	relying on all watchers to be stopped when deciding when a program has
739	finished (especially in interactive programs), but having a program	791	finished (especially in interactive programs), but having a program
740	that automatically loops as long as it has to and no longer by virtue	792	that automatically loops as long as it has to and no longer by virtue
741	of relying on its watchers stopping correctly, that is truly a thing of	793	of relying on its watchers stopping correctly, that is truly a thing of
742	beauty.	794	beauty.
		795
		796	This function is also I<mostly> exception-safe - you can break out of
		797	a C<ev_run> call by calling C<longjmp> in a callback, throwing a C++
		798	exception and so on. This does not decrement the C<ev_depth> value, nor
		799	will it clear any outstanding C<EVBREAK_ONE> breaks.
743		800
744	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle	801	A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
745	those events and any already outstanding ones, but will not wait and	802	those events and any already outstanding ones, but will not wait and
746	block your process in case there are no events and will return after one	803	block your process in case there are no events and will return after one
747	iteration of the loop. This is sometimes useful to poll and handle new	804	iteration of the loop. This is sometimes useful to poll and handle new
…		…
809	Can be used to make a call to C<ev_run> return early (but only after it	866	Can be used to make a call to C<ev_run> return early (but only after it
810	has processed all outstanding events). The C<how> argument must be either	867	has processed all outstanding events). The C<how> argument must be either
811	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or	868	C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
812	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.	869	C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
813		870
814	This "unloop state" will be cleared when entering C<ev_run> again.	871	This "break state" will be cleared on the next call to C<ev_run>.
815		872
816	It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO##	873	It is safe to call C<ev_break> from outside any C<ev_run> calls, too, in
		874	which case it will have no effect.
817		875
818	=item ev_ref (loop)	876	=item ev_ref (loop)
819		877
820	=item ev_unref (loop)	878	=item ev_unref (loop)
821		879
…		…
842	running when nothing else is active.	900	running when nothing else is active.
843		901
844	ev_signal exitsig;	902	ev_signal exitsig;
845	ev_signal_init (&exitsig, sig_cb, SIGINT);	903	ev_signal_init (&exitsig, sig_cb, SIGINT);
846	ev_signal_start (loop, &exitsig);	904	ev_signal_start (loop, &exitsig);
847	evf_unref (loop);	905	ev_unref (loop);
848		906
849	Example: For some weird reason, unregister the above signal handler again.	907	Example: For some weird reason, unregister the above signal handler again.
850		908
851	ev_ref (loop);	909	ev_ref (loop);
852	ev_signal_stop (loop, &exitsig);	910	ev_signal_stop (loop, &exitsig);
…		…
964	See also the locking example in the C<THREADS> section later in this	1022	See also the locking example in the C<THREADS> section later in this
965	document.	1023	document.
966		1024
967	=item ev_set_userdata (loop, void *data)	1025	=item ev_set_userdata (loop, void *data)
968		1026
969	=item ev_userdata (loop)	1027	=item void *ev_userdata (loop)
970		1028
971	Set and retrieve a single C<void *> associated with a loop. When	1029	Set and retrieve a single C<void *> associated with a loop. When
972	C<ev_set_userdata> has never been called, then C<ev_userdata> returns	1030	C<ev_set_userdata> has never been called, then C<ev_userdata> returns
973	C<0.>	1031	C<0>.
974		1032
975	These two functions can be used to associate arbitrary data with a loop,	1033	These two functions can be used to associate arbitrary data with a loop,
976	and are intended solely for the C<invoke_pending_cb>, C<release> and	1034	and are intended solely for the C<invoke_pending_cb>, C<release> and
977	C<acquire> callbacks described above, but of course can be (ab-)used for	1035	C<acquire> callbacks described above, but of course can be (ab-)used for
978	any other purpose as well.	1036	any other purpose as well.
…		…
1106	=item C<EV_FORK>	1164	=item C<EV_FORK>
1107		1165
1108	The event loop has been resumed in the child process after fork (see	1166	The event loop has been resumed in the child process after fork (see
1109	C<ev_fork>).	1167	C<ev_fork>).
1110		1168
		1169	=item C<EV_CLEANUP>
		1170
		1171	The event loop is about to be destroyed (see C<ev_cleanup>).
		1172
1111	=item C<EV_ASYNC>	1173	=item C<EV_ASYNC>
1112		1174
1113	The given async watcher has been asynchronously notified (see C<ev_async>).	1175	The given async watcher has been asynchronously notified (see C<ev_async>).
1114		1176
1115	=item C<EV_CUSTOM>	1177	=item C<EV_CUSTOM>
…		…
1136	programs, though, as the fd could already be closed and reused for another	1198	programs, though, as the fd could already be closed and reused for another
1137	thing, so beware.	1199	thing, so beware.
1138		1200
1139	=back	1201	=back
1140		1202
1141	=head2 WATCHER STATES
1142
1143	There are various watcher states mentioned throughout this manual -
1144	active, pending and so on. In this section these states and the rules to
1145	transition between them will be described in more detail - and while these
1146	rules might look complicated, they usually do "the right thing".
1147
1148	=over 4
1149
1150	=item initialiased
1151
1152	Before a watcher can be registered with the event looop it has to be
1153	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
1154	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
1155
1156	In this state it is simply some block of memory that is suitable for use
1157	in an event loop. It can be moved around, freed, reused etc. at will.
1158
1159	=item started/running/active
1160
1161	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
1162	property of the event loop, and is actively waiting for events. While in
1163	this state it cannot be accessed (except in a few documented ways), moved,
1164	freed or anything else - the only legal thing is to keep a pointer to it,
1165	and call libev functions on it that are documented to work on active watchers.
1166
1167	=item pending
1168
1169	If a watcher is active and libev determines that an event it is interested
1170	in has occurred (such as a timer expiring), it will become pending. It will
1171	stay in this pending state until either it is stopped or its callback is
1172	about to be invoked, so it is not normally pending inside the watcher
1173	callback.
1174
1175	The watcher might or might not be active while it is pending (for example,
1176	an expired non-repeating timer can be pending but no longer active). If it
1177	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
1178	but it is still property of the event loop at this time, so cannot be
1179	moved, freed or reused. And if it is active the rules described in the
1180	previous item still apply.
1181
1182	It is also possible to feed an event on a watcher that is not active (e.g.
1183	via C<ev_feed_event>), in which case it becomes pending without being
1184	active.
1185
1186	=item stopped
1187
1188	A watcher can be stopped implicitly by libev (in which case it might still
1189	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
1190	latter will clear any pending state the watcher might be in, regardless
1191	of whether it was active or not, so stopping a watcher explicitly before
1192	freeing it is often a good idea.
1193
1194	While stopped (and not pending) the watcher is essentially in the
1195	initialised state, that is it can be reused, moved, modified in any way
1196	you wish.
1197
1198	=back
1199
1200	=head2 GENERIC WATCHER FUNCTIONS	1203	=head2 GENERIC WATCHER FUNCTIONS
1201		1204
1202	=over 4	1205	=over 4
1203		1206
1204	=item C<ev_init> (ev_TYPE *watcher, callback)	1207	=item C<ev_init> (ev_TYPE *watcher, callback)
…		…
1345		1348
1346	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related	1349	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
1347	functions that do not need a watcher.	1350	functions that do not need a watcher.
1348		1351
1349	=back	1352	=back
1350
1351		1353
1352	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1354	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
1353		1355
1354	Each watcher has, by default, a member C<void *data> that you can change	1356	Each watcher has, by default, a member C<void *data> that you can change
1355	and read at any time: libev will completely ignore it. This can be used	1357	and read at any time: libev will completely ignore it. This can be used
…		…
1411	t2_cb (EV_P_ ev_timer *w, int revents)	1413	t2_cb (EV_P_ ev_timer *w, int revents)
1412	{	1414	{
1413	struct my_biggy big = (struct my_biggy *)	1415	struct my_biggy big = (struct my_biggy *)
1414	(((char *)w) - offsetof (struct my_biggy, t2));	1416	(((char *)w) - offsetof (struct my_biggy, t2));
1415	}	1417	}
		1418
		1419	=head2 WATCHER STATES
		1420
		1421	There are various watcher states mentioned throughout this manual -
		1422	active, pending and so on. In this section these states and the rules to
		1423	transition between them will be described in more detail - and while these
		1424	rules might look complicated, they usually do "the right thing".
		1425
		1426	=over 4
		1427
		1428	=item initialiased
		1429
		1430	Before a watcher can be registered with the event looop it has to be
		1431	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1432	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1433
		1434	In this state it is simply some block of memory that is suitable for use
		1435	in an event loop. It can be moved around, freed, reused etc. at will.
		1436
		1437	=item started/running/active
		1438
		1439	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1440	property of the event loop, and is actively waiting for events. While in
		1441	this state it cannot be accessed (except in a few documented ways), moved,
		1442	freed or anything else - the only legal thing is to keep a pointer to it,
		1443	and call libev functions on it that are documented to work on active watchers.
		1444
		1445	=item pending
		1446
		1447	If a watcher is active and libev determines that an event it is interested
		1448	in has occurred (such as a timer expiring), it will become pending. It will
		1449	stay in this pending state until either it is stopped or its callback is
		1450	about to be invoked, so it is not normally pending inside the watcher
		1451	callback.
		1452
		1453	The watcher might or might not be active while it is pending (for example,
		1454	an expired non-repeating timer can be pending but no longer active). If it
		1455	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1456	but it is still property of the event loop at this time, so cannot be
		1457	moved, freed or reused. And if it is active the rules described in the
		1458	previous item still apply.
		1459
		1460	It is also possible to feed an event on a watcher that is not active (e.g.
		1461	via C<ev_feed_event>), in which case it becomes pending without being
		1462	active.
		1463
		1464	=item stopped
		1465
		1466	A watcher can be stopped implicitly by libev (in which case it might still
		1467	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1468	latter will clear any pending state the watcher might be in, regardless
		1469	of whether it was active or not, so stopping a watcher explicitly before
		1470	freeing it is often a good idea.
		1471
		1472	While stopped (and not pending) the watcher is essentially in the
		1473	initialised state, that is it can be reused, moved, modified in any way
		1474	you wish.
		1475
		1476	=back
1416		1477
1417	=head2 WATCHER PRIORITY MODELS	1478	=head2 WATCHER PRIORITY MODELS
1418		1479
1419	Many event loops support I<watcher priorities>, which are usually small	1480	Many event loops support I<watcher priorities>, which are usually small
1420	integers that influence the ordering of event callback invocation	1481	integers that influence the ordering of event callback invocation
…		…
2239		2300
2240	=head2 C<ev_signal> - signal me when a signal gets signalled!	2301	=head2 C<ev_signal> - signal me when a signal gets signalled!
2241		2302
2242	Signal watchers will trigger an event when the process receives a specific	2303	Signal watchers will trigger an event when the process receives a specific
2243	signal one or more times. Even though signals are very asynchronous, libev	2304	signal one or more times. Even though signals are very asynchronous, libev
2244	will try it's best to deliver signals synchronously, i.e. as part of the	2305	will try its best to deliver signals synchronously, i.e. as part of the
2245	normal event processing, like any other event.	2306	normal event processing, like any other event.
2246		2307
2247	If you want signals to be delivered truly asynchronously, just use	2308	If you want signals to be delivered truly asynchronously, just use
2248	C<sigaction> as you would do without libev and forget about sharing	2309	C<sigaction> as you would do without libev and forget about sharing
2249	the signal. You can even use C<ev_async> from a signal handler to	2310	the signal. You can even use C<ev_async> from a signal handler to
…		…
2291	I<has> to modify the signal mask, at least temporarily.	2352	I<has> to modify the signal mask, at least temporarily.
2292		2353
2293	So I can't stress this enough: I<If you do not reset your signal mask when	2354	So I can't stress this enough: I<If you do not reset your signal mask when
2294	you expect it to be empty, you have a race condition in your code>. This	2355	you expect it to be empty, you have a race condition in your code>. This
2295	is not a libev-specific thing, this is true for most event libraries.	2356	is not a libev-specific thing, this is true for most event libraries.
		2357
		2358	=head3 The special problem of threads signal handling
		2359
		2360	POSIX threads has problematic signal handling semantics, specifically,
		2361	a lot of functionality (sigfd, sigwait etc.) only really works if all
		2362	threads in a process block signals, which is hard to achieve.
		2363
		2364	When you want to use sigwait (or mix libev signal handling with your own
		2365	for the same signals), you can tackle this problem by globally blocking
		2366	all signals before creating any threads (or creating them with a fully set
		2367	sigprocmask) and also specifying the C<EVFLAG_NOSIGMASK> when creating
		2368	loops. Then designate one thread as "signal receiver thread" which handles
		2369	these signals. You can pass on any signals that libev might be interested
		2370	in by calling C<ev_feed_signal>.
2296		2371
2297	=head3 Watcher-Specific Functions and Data Members	2372	=head3 Watcher-Specific Functions and Data Members
2298		2373
2299	=over 4	2374	=over 4
2300		2375
…		…
3074	disadvantage of having to use multiple event loops (which do not support	3149	disadvantage of having to use multiple event loops (which do not support
3075	signal watchers).	3150	signal watchers).
3076		3151
3077	When this is not possible, or you want to use the default loop for	3152	When this is not possible, or you want to use the default loop for
3078	other reasons, then in the process that wants to start "fresh", call	3153	other reasons, then in the process that wants to start "fresh", call
3079	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3154	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
3080	the default loop will "orphan" (not stop) all registered watchers, so you	3155	Destroying the default loop will "orphan" (not stop) all registered
3081	have to be careful not to execute code that modifies those watchers. Note	3156	watchers, so you have to be careful not to execute code that modifies
3082	also that in that case, you have to re-register any signal watchers.	3157	those watchers. Note also that in that case, you have to re-register any
		3158	signal watchers.
3083		3159
3084	=head3 Watcher-Specific Functions and Data Members	3160	=head3 Watcher-Specific Functions and Data Members
3085		3161
3086	=over 4	3162	=over 4
3087		3163
3088	=item ev_fork_init (ev_signal *, callback)	3164	=item ev_fork_init (ev_fork *, callback)
3089		3165
3090	Initialises and configures the fork watcher - it has no parameters of any	3166	Initialises and configures the fork watcher - it has no parameters of any
3091	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,	3167	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3092	believe me.	3168	really.
3093		3169
3094	=back	3170	=back
		3171
		3172
		3173	=head2 C<ev_cleanup> - even the best things end
		3174
		3175	Cleanup watchers are called just before the event loop is being destroyed
		3176	by a call to C<ev_loop_destroy>.
		3177
		3178	While there is no guarantee that the event loop gets destroyed, cleanup
		3179	watchers provide a convenient method to install cleanup hooks for your
		3180	program, worker threads and so on - you just to make sure to destroy the
		3181	loop when you want them to be invoked.
		3182
		3183	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3184	all other watchers, they do not keep a reference to the event loop (which
		3185	makes a lot of sense if you think about it). Like all other watchers, you
		3186	can call libev functions in the callback, except C<ev_cleanup_start>.
		3187
		3188	=head3 Watcher-Specific Functions and Data Members
		3189
		3190	=over 4
		3191
		3192	=item ev_cleanup_init (ev_cleanup *, callback)
		3193
		3194	Initialises and configures the cleanup watcher - it has no parameters of
		3195	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3196	pointless, I assure you.
		3197
		3198	=back
		3199
		3200	Example: Register an atexit handler to destroy the default loop, so any
		3201	cleanup functions are called.
		3202
		3203	static void
		3204	program_exits (void)
		3205	{
		3206	ev_loop_destroy (EV_DEFAULT_UC);
		3207	}
		3208
		3209	...
		3210	atexit (program_exits);
3095		3211
3096		3212
3097	=head2 C<ev_async> - how to wake up an event loop	3213	=head2 C<ev_async> - how to wake up an event loop
3098		3214
3099	In general, you cannot use an C<ev_run> from multiple threads or other	3215	In general, you cannot use an C<ev_run> from multiple threads or other
…		…
3106	it by calling C<ev_async_send>, which is thread- and signal safe.	3222	it by calling C<ev_async_send>, which is thread- and signal safe.
3107		3223
3108	This functionality is very similar to C<ev_signal> watchers, as signals,	3224	This functionality is very similar to C<ev_signal> watchers, as signals,
3109	too, are asynchronous in nature, and signals, too, will be compressed	3225	too, are asynchronous in nature, and signals, too, will be compressed
3110	(i.e. the number of callback invocations may be less than the number of	3226	(i.e. the number of callback invocations may be less than the number of
3111	C<ev_async_sent> calls).	3227	C<ev_async_sent> calls). In fact, you could use signal watchers as a kind
		3228	of "global async watchers" by using a watcher on an otherwise unused
		3229	signal, and C<ev_feed_signal> to signal this watcher from another thread,
		3230	even without knowing which loop owns the signal.
3112		3231
3113	Unlike C<ev_signal> watchers, C<ev_async> works with any event loop, not	3232	Unlike C<ev_signal> watchers, C<ev_async> works with any event loop, not
3114	just the default loop.	3233	just the default loop.
3115		3234
3116	=head3 Queueing	3235	=head3 Queueing
…		…
3292	Feed an event on the given fd, as if a file descriptor backend detected	3411	Feed an event on the given fd, as if a file descriptor backend detected
3293	the given events it.	3412	the given events it.
3294		3413
3295	=item ev_feed_signal_event (loop, int signum)	3414	=item ev_feed_signal_event (loop, int signum)
3296		3415
3297	Feed an event as if the given signal occurred (C<loop> must be the default	3416	Feed an event as if the given signal occurred. See also C<ev_feed_signal>,
3298	loop!).	3417	which is async-safe.
		3418
		3419	=back
		3420
		3421
		3422	=head1 COMMON OR USEFUL IDIOMS (OR BOTH)
		3423
		3424	This section explains some common idioms that are not immediately
		3425	obvious. Note that examples are sprinkled over the whole manual, and this
		3426	section only contains stuff that wouldn't fit anywhere else.
		3427
		3428	=over 4
		3429
		3430	=item Model/nested event loop invocations and exit conditions.
		3431
		3432	Often (especially in GUI toolkits) there are places where you have
		3433	I<modal> interaction, which is most easily implemented by recursively
		3434	invoking C<ev_run>.
		3435
		3436	This brings the problem of exiting - a callback might want to finish the
		3437	main C<ev_run> call, but not the nested one (e.g. user clicked "Quit", but
		3438	a modal "Are you sure?" dialog is still waiting), or just the nested one
		3439	and not the main one (e.g. user clocked "Ok" in a modal dialog), or some
		3440	other combination: In these cases, C<ev_break> will not work alone.
		3441
		3442	The solution is to maintain "break this loop" variable for each C<ev_run>
		3443	invocation, and use a loop around C<ev_run> until the condition is
		3444	triggered, using C<EVRUN_ONCE>:
		3445
		3446	// main loop
		3447	int exit_main_loop = 0;
		3448
		3449	while (!exit_main_loop)
		3450	ev_run (EV_DEFAULT_ EVRUN_ONCE);
		3451
		3452	// in a model watcher
		3453	int exit_nested_loop = 0;
		3454
		3455	while (!exit_nested_loop)
		3456	ev_run (EV_A_ EVRUN_ONCE);
		3457
		3458	To exit from any of these loops, just set the corresponding exit variable:
		3459
		3460	// exit modal loop
		3461	exit_nested_loop = 1;
		3462
		3463	// exit main program, after modal loop is finished
		3464	exit_main_loop = 1;
		3465
		3466	// exit both
		3467	exit_main_loop = exit_nested_loop = 1;
3299		3468
3300	=back	3469	=back
3301		3470
3302		3471
3303	=head1 LIBEVENT EMULATION	3472	=head1 LIBEVENT EMULATION
3304		3473
3305	Libev offers a compatibility emulation layer for libevent. It cannot	3474	Libev offers a compatibility emulation layer for libevent. It cannot
3306	emulate the internals of libevent, so here are some usage hints:	3475	emulate the internals of libevent, so here are some usage hints:
3307		3476
3308	=over 4	3477	=over 4
		3478
		3479	=item * Only the libevent-1.4.1-beta API is being emulated.
		3480
		3481	This was the newest libevent version available when libev was implemented,
		3482	and is still mostly unchanged in 2010.
3309		3483
3310	=item * Use it by including <event.h>, as usual.	3484	=item * Use it by including <event.h>, as usual.
3311		3485
3312	=item * The following members are fully supported: ev_base, ev_callback,	3486	=item * The following members are fully supported: ev_base, ev_callback,
3313	ev_arg, ev_fd, ev_res, ev_events.	3487	ev_arg, ev_fd, ev_res, ev_events.
…		…
3319	=item * Priorities are not currently supported. Initialising priorities	3493	=item * Priorities are not currently supported. Initialising priorities
3320	will fail and all watchers will have the same priority, even though there	3494	will fail and all watchers will have the same priority, even though there
3321	is an ev_pri field.	3495	is an ev_pri field.
3322		3496
3323	=item * In libevent, the last base created gets the signals, in libev, the	3497	=item * In libevent, the last base created gets the signals, in libev, the
3324	first base created (== the default loop) gets the signals.	3498	base that registered the signal gets the signals.
3325		3499
3326	=item * Other members are not supported.	3500	=item * Other members are not supported.
3327		3501
3328	=item * The libev emulation is I<not> ABI compatible to libevent, you need	3502	=item * The libev emulation is I<not> ABI compatible to libevent, you need
3329	to use the libev header file and library.	3503	to use the libev header file and library.
…		…
3348	Care has been taken to keep the overhead low. The only data member the C++	3522	Care has been taken to keep the overhead low. The only data member the C++
3349	classes add (compared to plain C-style watchers) is the event loop pointer	3523	classes add (compared to plain C-style watchers) is the event loop pointer
3350	that the watcher is associated with (or no additional members at all if	3524	that the watcher is associated with (or no additional members at all if
3351	you disable C<EV_MULTIPLICITY> when embedding libev).	3525	you disable C<EV_MULTIPLICITY> when embedding libev).
3352		3526
3353	Currently, functions, and static and non-static member functions can be	3527	Currently, functions, static and non-static member functions and classes
3354	used as callbacks. Other types should be easy to add as long as they only	3528	with C<operator ()> can be used as callbacks. Other types should be easy
3355	need one additional pointer for context. If you need support for other	3529	to add as long as they only need one additional pointer for context. If
3356	types of functors please contact the author (preferably after implementing	3530	you need support for other types of functors please contact the author
3357	it).	3531	(preferably after implementing it).
3358		3532
3359	Here is a list of things available in the C<ev> namespace:	3533	Here is a list of things available in the C<ev> namespace:
3360		3534
3361	=over 4	3535	=over 4
3362		3536
…		…
4706	structure (guaranteed by POSIX but not by ISO C for example), but it also	4880	structure (guaranteed by POSIX but not by ISO C for example), but it also
4707	assumes that the same (machine) code can be used to call any watcher	4881	assumes that the same (machine) code can be used to call any watcher
4708	callback: The watcher callbacks have different type signatures, but libev	4882	callback: The watcher callbacks have different type signatures, but libev
4709	calls them using an C<ev_watcher *> internally.	4883	calls them using an C<ev_watcher *> internally.
4710		4884
		4885	=item pointer accesses must be thread-atomic
		4886
		4887	Accessing a pointer value must be atomic, it must both be readable and
		4888	writable in one piece - this is the case on all current architectures.
		4889
4711	=item C<sig_atomic_t volatile> must be thread-atomic as well	4890	=item C<sig_atomic_t volatile> must be thread-atomic as well
4712		4891
4713	The type C<sig_atomic_t volatile> (or whatever is defined as	4892	The type C<sig_atomic_t volatile> (or whatever is defined as
4714	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different	4893	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
4715	threads. This is not part of the specification for C<sig_atomic_t>, but is	4894	threads. This is not part of the specification for C<sig_atomic_t>, but is
…		…
4821	=back	5000	=back
4822		5001
4823		5002
4824	=head1 PORTING FROM LIBEV 3.X TO 4.X	5003	=head1 PORTING FROM LIBEV 3.X TO 4.X
4825		5004
4826	The major version 4 introduced some minor incompatible changes to the API.	5005	The major version 4 introduced some incompatible changes to the API.
4827		5006
4828	At the moment, the C<ev.h> header file tries to implement superficial	5007	At the moment, the C<ev.h> header file provides compatibility definitions
4829	compatibility, so most programs should still compile. Those might be	5008	for all changes, so most programs should still compile. The compatibility
4830	removed in later versions of libev, so better update early than late.	5009	layer might be removed in later versions of libev, so better update to the
		5010	new API early than late.
4831		5011
4832	=over 4	5012	=over 4
		5013
		5014	=item C<EV_COMPAT3> backwards compatibility mechanism
		5015
		5016	The backward compatibility mechanism can be controlled by
		5017	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		5018	section.
		5019
		5020	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		5021
		5022	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		5023
		5024	ev_loop_destroy (EV_DEFAULT_UC);
		5025	ev_loop_fork (EV_DEFAULT);
4833		5026
4834	=item function/symbol renames	5027	=item function/symbol renames
4835		5028
4836	A number of functions and symbols have been renamed:	5029	A number of functions and symbols have been renamed:
4837		5030
…		…
4856	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme	5049	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
4857	as all other watcher types. Note that C<ev_loop_fork> is still called	5050	as all other watcher types. Note that C<ev_loop_fork> is still called
4858	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>	5051	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4859	typedef.	5052	typedef.
4860		5053
4861	=item C<EV_COMPAT3> backwards compatibility mechanism
4862
4863	The backward compatibility mechanism can be controlled by
4864	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4865	section.
4866
4867	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	5054	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4868		5055
4869	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	5056	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4870	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	5057	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
4871	and work, but the library code will of course be larger.	5058	and work, but the library code will of course be larger.
…		…
4945		5132
4946	=back	5133	=back
4947		5134
4948	=head1 AUTHOR	5135	=head1 AUTHOR
4949		5136
4950	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5137	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
		5138	Magnusson and Emanuele Giaquinta.
4951		5139

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Comparing libev/ev.pod (file contents): Revision 1.319 by root, Fri Oct 22 10:09:12 2010 UTC vs. Revision 1.349 by root, Mon Jan 10 01:58:55 2011 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.319 by root, Fri Oct 22 10:09:12 2010 UTC vs.
Revision 1.349 by root, Mon Jan 10 01:58:55 2011 UTC