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

Comparing libev/ev.pod (file contents):
Revision 1.318 by root, Fri Oct 22 09:40:22 2010 UTC vs.
Revision 1.335 by root, Mon Oct 25 10:32:05 2010 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
…		…
225	probe for if you specify no backends explicitly.	234	probe for if you specify no backends explicitly.
226		235
227	=item unsigned int ev_embeddable_backends ()	236	=item unsigned int ev_embeddable_backends ()
228		237
229	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
230	is the theoretical, all-platform, value. To find which backends	239	value is platform-specific but can include backends not available on the
231	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
232	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	241	the current system, you would need to look at C<ev_embeddable_backends ()
233	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)) [NOT REENTRANT]
238		247
…		…
292	...	301	...
293	ev_set_syserr_cb (fatal_error);	302	ev_set_syserr_cb (fatal_error);
294		303
295	=back	304	=back
296		305
297	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	306	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
298		307
299	An event loop is described by a C<struct ev_loop *> (the C<struct> is	308	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	309	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).	310	libev 3 had an C<ev_loop> function colliding with the struct name).
302		311
303	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
304	supports signals and child events, and dynamically created event loops	313	supports child process events, and dynamically created event loops which
305	which do not.	314	do not.
306		315
307	=over 4	316	=over 4
308		317
309	=item struct ev_loop *ev_default_loop (unsigned int flags)	318	=item struct ev_loop *ev_default_loop (unsigned int flags)
310		319
311	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
312	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
313	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
314	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".
315		330
316	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
317	function.	332	function (or via the C<EV_DEFAULT> macro).
318		333
319	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
320	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
321	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).
322		338
323	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,
324	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
325	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
326	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
327	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	343	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
328	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.
329		363
330	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
331	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>).
332		366
333	The following flags are supported:	367	The following flags are supported:
…		…
551	If one or more of the backend flags are or'ed into the flags value,	585	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	586	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	587	here). If none are specified, all backends in C<ev_recommended_backends
554	()> will be tried.	588	()> will be tried.
555		589
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.	590	Example: Try to create a event loop that uses epoll and nothing else.
583		591
584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	592	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
585	if (!epoller)	593	if (!epoller)
586	fatal ("no epoll found here, maybe it hides under your chair");	594	fatal ("no epoll found here, maybe it hides under your chair");
587		595
		596	Example: Use whatever libev has to offer, but make sure that kqueue is
		597	used if available.
		598
		599	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () \| EVBACKEND_KQUEUE);
		600
588	=item ev_default_destroy ()	601	=item ev_loop_destroy (loop)
589		602
590	Destroys the default loop (frees all memory and kernel state etc.). None	603	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	604	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	605	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,	606	responsibility to either stop all watchers cleanly yourself I<before>
594	or cope with the fact afterwards (which is usually the easiest thing, you	607	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).	608	the easiest thing, you can just ignore the watchers and/or C<free ()> them
		609	for example).
596		610
597	Note that certain global state, such as signal state (and installed signal	611	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	612	handlers), will not be freed by this function, and related watchers (such
599	as signal and child watchers) would need to be stopped manually.	613	as signal and child watchers) would need to be stopped manually.
600		614
601	In general it is not advisable to call this function except in the	615	This function is normally used on loop objects allocated by
602	rare occasion where you really need to free e.g. the signal handling	616	C<ev_loop_new>, but it can also be used on the default loop returned by
		617	C<ev_default_loop>, in which case it is not thread-safe.
		618
		619	Note that it is not advisable to call this function on the default loop
		620	except in the rare occasion where you really need to free it's resources.
603	pipe fds. If you need dynamically allocated loops it is better to use	621	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>.	622	and C<ev_loop_destroy>.
605		623
606	=item ev_loop_destroy (loop)	624	=item ev_loop_fork (loop)
607		625
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	626	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	627	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	628	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	629	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	630	child before resuming or calling C<ev_run>.
618	functions, and it will only take effect at the next C<ev_run> iteration.
619		631
620	Again, you I<have> to call it on I<any> loop that you want to re-use after	632	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	633	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	634	because some kernel interfaces cough I<kqueue> cough do funny things
623	during fork.	635	during fork.
…		…
628	call it at all (in fact, C<epoll> is so badly broken that it makes a	640	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	641	difference, but libev will usually detect this case on its own and do a
630	costly reset of the backend).	642	costly reset of the backend).
631		643
632	The function itself is quite fast and it's usually not a problem to call	644	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	645	it just in case after a fork.
634	quite nicely into a call to C<pthread_atfork>:
635		646
		647	Example: Automate calling C<ev_loop_fork> on the default loop when
		648	using pthreads.
		649
		650	static void
		651	post_fork_child (void)
		652	{
		653	ev_loop_fork (EV_DEFAULT);
		654	}
		655
		656	...
636	pthread_atfork (0, 0, ev_default_fork);	657	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		658
645	=item int ev_is_default_loop (loop)	659	=item int ev_is_default_loop (loop)
646		660
647	Returns true when the given loop is, in fact, the default loop, and false	661	Returns true when the given loop is, in fact, the default loop, and false
648	otherwise.	662	otherwise.
…		…
1106	=item C<EV_FORK>	1120	=item C<EV_FORK>
1107		1121
1108	The event loop has been resumed in the child process after fork (see	1122	The event loop has been resumed in the child process after fork (see
1109	C<ev_fork>).	1123	C<ev_fork>).
1110		1124
		1125	=item C<EV_CLEANUP>
		1126
		1127	The event loop is about to be destroyed (see C<ev_cleanup>).
		1128
1111	=item C<EV_ASYNC>	1129	=item C<EV_ASYNC>
1112		1130
1113	The given async watcher has been asynchronously notified (see C<ev_async>).	1131	The given async watcher has been asynchronously notified (see C<ev_async>).
1114		1132
1115	=item C<EV_CUSTOM>	1133	=item C<EV_CUSTOM>
…		…
1136	programs, though, as the fd could already be closed and reused for another	1154	programs, though, as the fd could already be closed and reused for another
1137	thing, so beware.	1155	thing, so beware.
1138		1156
1139	=back	1157	=back
1140		1158
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	1159	=head2 GENERIC WATCHER FUNCTIONS
1201		1160
1202	=over 4	1161	=over 4
1203		1162
1204	=item C<ev_init> (ev_TYPE *watcher, callback)	1163	=item C<ev_init> (ev_TYPE *watcher, callback)
…		…
1345		1304
1346	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related	1305	See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
1347	functions that do not need a watcher.	1306	functions that do not need a watcher.
1348		1307
1349	=back	1308	=back
1350
1351		1309
1352	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	1310	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
1353		1311
1354	Each watcher has, by default, a member C<void *data> that you can change	1312	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	1313	and read at any time: libev will completely ignore it. This can be used
…		…
1411	t2_cb (EV_P_ ev_timer *w, int revents)	1369	t2_cb (EV_P_ ev_timer *w, int revents)
1412	{	1370	{
1413	struct my_biggy big = (struct my_biggy *)	1371	struct my_biggy big = (struct my_biggy *)
1414	(((char *)w) - offsetof (struct my_biggy, t2));	1372	(((char *)w) - offsetof (struct my_biggy, t2));
1415	}	1373	}
		1374
		1375	=head2 WATCHER STATES
		1376
		1377	There are various watcher states mentioned throughout this manual -
		1378	active, pending and so on. In this section these states and the rules to
		1379	transition between them will be described in more detail - and while these
		1380	rules might look complicated, they usually do "the right thing".
		1381
		1382	=over 4
		1383
		1384	=item initialiased
		1385
		1386	Before a watcher can be registered with the event looop it has to be
		1387	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1388	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1389
		1390	In this state it is simply some block of memory that is suitable for use
		1391	in an event loop. It can be moved around, freed, reused etc. at will.
		1392
		1393	=item started/running/active
		1394
		1395	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1396	property of the event loop, and is actively waiting for events. While in
		1397	this state it cannot be accessed (except in a few documented ways), moved,
		1398	freed or anything else - the only legal thing is to keep a pointer to it,
		1399	and call libev functions on it that are documented to work on active watchers.
		1400
		1401	=item pending
		1402
		1403	If a watcher is active and libev determines that an event it is interested
		1404	in has occurred (such as a timer expiring), it will become pending. It will
		1405	stay in this pending state until either it is stopped or its callback is
		1406	about to be invoked, so it is not normally pending inside the watcher
		1407	callback.
		1408
		1409	The watcher might or might not be active while it is pending (for example,
		1410	an expired non-repeating timer can be pending but no longer active). If it
		1411	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1412	but it is still property of the event loop at this time, so cannot be
		1413	moved, freed or reused. And if it is active the rules described in the
		1414	previous item still apply.
		1415
		1416	It is also possible to feed an event on a watcher that is not active (e.g.
		1417	via C<ev_feed_event>), in which case it becomes pending without being
		1418	active.
		1419
		1420	=item stopped
		1421
		1422	A watcher can be stopped implicitly by libev (in which case it might still
		1423	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1424	latter will clear any pending state the watcher might be in, regardless
		1425	of whether it was active or not, so stopping a watcher explicitly before
		1426	freeing it is often a good idea.
		1427
		1428	While stopped (and not pending) the watcher is essentially in the
		1429	initialised state, that is it can be reused, moved, modified in any way
		1430	you wish.
		1431
		1432	=back
1416		1433
1417	=head2 WATCHER PRIORITY MODELS	1434	=head2 WATCHER PRIORITY MODELS
1418		1435
1419	Many event loops support I<watcher priorities>, which are usually small	1436	Many event loops support I<watcher priorities>, which are usually small
1420	integers that influence the ordering of event callback invocation	1437	integers that influence the ordering of event callback invocation
…		…
3074	disadvantage of having to use multiple event loops (which do not support	3091	disadvantage of having to use multiple event loops (which do not support
3075	signal watchers).	3092	signal watchers).
3076		3093
3077	When this is not possible, or you want to use the default loop for	3094	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	3095	other reasons, then in the process that wants to start "fresh", call
3079	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3096	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	3097	Destroying the default loop will "orphan" (not stop) all registered
3081	have to be careful not to execute code that modifies those watchers. Note	3098	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.	3099	those watchers. Note also that in that case, you have to re-register any
		3100	signal watchers.
3083		3101
3084	=head3 Watcher-Specific Functions and Data Members	3102	=head3 Watcher-Specific Functions and Data Members
3085		3103
3086	=over 4	3104	=over 4
3087		3105
3088	=item ev_fork_init (ev_signal *, callback)	3106	=item ev_fork_init (ev_fork *, callback)
3089		3107
3090	Initialises and configures the fork watcher - it has no parameters of any	3108	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,	3109	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3092	believe me.	3110	really.
3093		3111
3094	=back	3112	=back
		3113
		3114
		3115	=head2 C<ev_cleanup> - even the best things end
		3116
		3117	Cleanup watchers are called just before the event loop is being destroyed
		3118	by a call to C<ev_loop_destroy>.
		3119
		3120	While there is no guarantee that the event loop gets destroyed, cleanup
		3121	watchers provide a convenient method to install cleanup hooks for your
		3122	program, worker threads and so on - you just to make sure to destroy the
		3123	loop when you want them to be invoked.
		3124
		3125	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3126	all other watchers, they do not keep a reference to the event loop (which
		3127	makes a lot of sense if you think about it). Like all other watchers, you
		3128	can call libev functions in the callback, except C<ev_cleanup_start>.
		3129
		3130	=head3 Watcher-Specific Functions and Data Members
		3131
		3132	=over 4
		3133
		3134	=item ev_cleanup_init (ev_cleanup *, callback)
		3135
		3136	Initialises and configures the cleanup watcher - it has no parameters of
		3137	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3138	pointless, I assure you.
		3139
		3140	=back
		3141
		3142	Example: Register an atexit handler to destroy the default loop, so any
		3143	cleanup functions are called.
		3144
		3145	static void
		3146	program_exits (void)
		3147	{
		3148	ev_loop_destroy (EV_DEFAULT_UC);
		3149	}
		3150
		3151	...
		3152	atexit (program_exits);
3095		3153
3096		3154
3097	=head2 C<ev_async> - how to wake up an event loop	3155	=head2 C<ev_async> - how to wake up an event loop
3098		3156
3099	In general, you cannot use an C<ev_run> from multiple threads or other	3157	In general, you cannot use an C<ev_run> from multiple threads or other
…		…
4706	structure (guaranteed by POSIX but not by ISO C for example), but it also	4764	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	4765	assumes that the same (machine) code can be used to call any watcher
4708	callback: The watcher callbacks have different type signatures, but libev	4766	callback: The watcher callbacks have different type signatures, but libev
4709	calls them using an C<ev_watcher *> internally.	4767	calls them using an C<ev_watcher *> internally.
4710		4768
		4769	=item pointer accesses must be thread-atomic
		4770
		4771	Accessing a pointer value must be atomic, it must both be readable and
		4772	writable in one piece - this is the case on all current architectures.
		4773
4711	=item C<sig_atomic_t volatile> must be thread-atomic as well	4774	=item C<sig_atomic_t volatile> must be thread-atomic as well
4712		4775
4713	The type C<sig_atomic_t volatile> (or whatever is defined as	4776	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	4777	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	4778	threads. This is not part of the specification for C<sig_atomic_t>, but is
…		…
4821	=back	4884	=back
4822		4885
4823		4886
4824	=head1 PORTING FROM LIBEV 3.X TO 4.X	4887	=head1 PORTING FROM LIBEV 3.X TO 4.X
4825		4888
4826	The major version 4 introduced some minor incompatible changes to the API.	4889	The major version 4 introduced some incompatible changes to the API.
4827		4890
4828	At the moment, the C<ev.h> header file tries to implement superficial	4891	At the moment, the C<ev.h> header file provides compatibility definitions
4829	compatibility, so most programs should still compile. Those might be	4892	for all changes, so most programs should still compile. The compatibility
4830	removed in later versions of libev, so better update early than late.	4893	layer might be removed in later versions of libev, so better update to the
		4894	new API early than late.
4831		4895
4832	=over 4	4896	=over 4
		4897
		4898	=item C<EV_COMPAT3> backwards compatibility mechanism
		4899
		4900	The backward compatibility mechanism can be controlled by
		4901	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4902	section.
		4903
		4904	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4905
		4906	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4907
		4908	ev_loop_destroy (EV_DEFAULT_UC);
		4909	ev_loop_fork (EV_DEFAULT);
4833		4910
4834	=item function/symbol renames	4911	=item function/symbol renames
4835		4912
4836	A number of functions and symbols have been renamed:	4913	A number of functions and symbols have been renamed:
4837		4914
…		…
4856	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme	4933	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	4934	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>	4935	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4859	typedef.	4936	typedef.
4860		4937
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>	4938	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4868		4939
4869	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4940	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4870	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4941	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
4871	and work, but the library code will of course be larger.	4942	and work, but the library code will of course be larger.
…		…
4945		5016
4946	=back	5017	=back
4947		5018
4948	=head1 AUTHOR	5019	=head1 AUTHOR
4949		5020
4950	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5021	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
		5022	Magnusson and Emanuele Giaquinta.
4951		5023

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Comparing libev/ev.pod (file contents): Revision 1.318 by root, Fri Oct 22 09:40:22 2010 UTC vs. Revision 1.335 by root, Mon Oct 25 10:32:05 2010 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.318 by root, Fri Oct 22 09:40:22 2010 UTC vs.
Revision 1.335 by root, Mon Oct 25 10:32:05 2010 UTC