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

Comparing libev/ev.pod (file contents):
Revision 1.310 by root, Thu Oct 21 12:32:47 2010 UTC vs.
Revision 1.333 by root, Mon Oct 25 09:31:47 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);
…		…
124	this argument.	124	this argument.
125		125
126	=head2 TIME REPRESENTATION	126	=head2 TIME REPRESENTATION
127		127
128	Libev represents time as a single floating point number, representing	128	Libev represents time as a single floating point number, representing
129	the (fractional) number of seconds since the (POSIX) epoch (in practise	129	the (fractional) number of seconds since the (POSIX) epoch (in practice
130	somewhere near the beginning of 1970, details are complicated, don't	130	somewhere near the beginning of 1970, details are complicated, don't
131	ask). This type is called C<ev_tstamp>, which is what you should use	131	ask). This type is called C<ev_tstamp>, which is what you should use
132	too. It usually aliases to the C<double> type in C. When you need to do	132	too. It usually aliases to the C<double> type in C. When you need to do
133	any calculations on it, you should treat it as some floating point value.	133	any calculations on it, you should treat it as some floating point value.
134		134
…		…
165		165
166	=item ev_tstamp ev_time ()	166	=item ev_tstamp ev_time ()
167		167
168	Returns the current time as libev would use it. Please note that the	168	Returns the current time as libev would use it. Please note that the
169	C<ev_now> function is usually faster and also often returns the timestamp	169	C<ev_now> function is usually faster and also often returns the timestamp
170	you actually want to know.	170	you actually want to know. Also interesting is the combination of
		171	C<ev_update_now> and C<ev_now>.
171		172
172	=item ev_sleep (ev_tstamp interval)	173	=item ev_sleep (ev_tstamp interval)
173		174
174	Sleep for the given interval: The current thread will be blocked until	175	Sleep for the given interval: The current thread will be blocked until
175	either it is interrupted or the given time interval has passed. Basically	176	either it is interrupted or the given time interval has passed. Basically
…		…
192	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
193	compatible to older versions, so a larger minor version alone is usually	194	compatible to older versions, so a larger minor version alone is usually
194	not a problem.	195	not a problem.
195		196
196	Example: Make sure we haven't accidentally been linked against the wrong	197	Example: Make sure we haven't accidentally been linked against the wrong
197	version (note, however, that this will not detect ABI mismatches :).	198	version (note, however, that this will not detect other ABI mismatches,
		199	such as LFS or reentrancy).
198		200
199	assert (("libev version mismatch",	201	assert (("libev version mismatch",
200	ev_version_major () == EV_VERSION_MAJOR	202	ev_version_major () == EV_VERSION_MAJOR
201	&& ev_version_minor () >= EV_VERSION_MINOR));	203	&& ev_version_minor () >= EV_VERSION_MINOR));
202		204
…		…
213	assert (("sorry, no epoll, no sex",	215	assert (("sorry, no epoll, no sex",
214	ev_supported_backends () & EVBACKEND_EPOLL));	216	ev_supported_backends () & EVBACKEND_EPOLL));
215		217
216	=item unsigned int ev_recommended_backends ()	218	=item unsigned int ev_recommended_backends ()
217		219
218	Return the set of all backends compiled into this binary of libev and also	220	Return the set of all backends compiled into this binary of libev and
219	recommended for this platform. This set is often smaller than the one	221	also recommended for this platform, meaning it will work for most file
		222	descriptor types. This set is often smaller than the one returned by
220	returned by C<ev_supported_backends>, as for example kqueue is broken on	223	C<ev_supported_backends>, as for example kqueue is broken on most BSDs
221	most BSDs and will not be auto-detected unless you explicitly request it	224	and will not be auto-detected unless you explicitly request it (assuming
222	(assuming you know what you are doing). This is the set of backends that	225	you know what you are doing). This is the set of backends that libev will
223	libev will probe for if you specify no backends explicitly.	226	probe for if you specify no backends explicitly.
224		227
225	=item unsigned int ev_embeddable_backends ()	228	=item unsigned int ev_embeddable_backends ()
226		229
227	Returns the set of backends that are embeddable in other event loops. This	230	Returns the set of backends that are embeddable in other event loops. This
228	is the theoretical, all-platform, value. To find which backends	231	value is platform-specific but can include backends not available on the
229	might be supported on the current system, you would need to look at	232	current system. To find which embeddable backends might be supported on
230	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	233	the current system, you would need to look at C<ev_embeddable_backends ()
231	recommended ones.	234	& ev_supported_backends ()>, likewise for recommended ones.
232		235
233	See the description of C<ev_embed> watchers for more info.	236	See the description of C<ev_embed> watchers for more info.
234		237
235	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]	238	=item ev_set_allocator (void (cb)(void *ptr, long size)) [NOT REENTRANT]
236		239
…		…
290	...	293	...
291	ev_set_syserr_cb (fatal_error);	294	ev_set_syserr_cb (fatal_error);
292		295
293	=back	296	=back
294		297
295	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	298	=head1 FUNCTIONS CONTROLLING EVENT LOOPS
296		299
297	An event loop is described by a C<struct ev_loop *> (the C<struct> is	300	An event loop is described by a C<struct ev_loop *> (the C<struct> is
298	I<not> optional in case unless libev 3 compatibility is disabled, as libev	301	I<not> optional in this case unless libev 3 compatibility is disabled, as
299	3 had an C<ev_loop> function colliding with the struct name).	302	libev 3 had an C<ev_loop> function colliding with the struct name).
300		303
301	The library knows two types of such loops, the I<default> loop, which	304	The library knows two types of such loops, the I<default> loop, which
302	supports signals and child events, and dynamically created event loops	305	supports child process events, and dynamically created event loops which
303	which do not.	306	do not.
304		307
305	=over 4	308	=over 4
306		309
307	=item struct ev_loop *ev_default_loop (unsigned int flags)	310	=item struct ev_loop *ev_default_loop (unsigned int flags)
308		311
309	This will initialise the default event loop if it hasn't been initialised	312	This returns the "default" event loop object, which is what you should
310	yet and return it. If the default loop could not be initialised, returns	313	normally use when you just need "the event loop". Event loop objects and
311	false. If it already was initialised it simply returns it (and ignores the	314	the C<flags> parameter are described in more detail in the entry for
312	flags. If that is troubling you, check C<ev_backend ()> afterwards).	315	C<ev_loop_new>.
		316
		317	If the default loop is already initialised then this function simply
		318	returns it (and ignores the flags. If that is troubling you, check
		319	C<ev_backend ()> afterwards). Otherwise it will create it with the given
		320	flags, which should almost always be C<0>, unless the caller is also the
		321	one calling C<ev_run> or otherwise qualifies as "the main program".
313		322
314	If you don't know what event loop to use, use the one returned from this	323	If you don't know what event loop to use, use the one returned from this
315	function.	324	function (or via the C<EV_DEFAULT> macro).
316		325
317	Note that this function is I<not> thread-safe, so if you want to use it	326	Note that this function is I<not> thread-safe, so if you want to use it
318	from multiple threads, you have to lock (note also that this is unlikely,	327	from multiple threads, you have to employ some kind of mutex (note also
319	as loops cannot be shared easily between threads anyway).	328	that this case is unlikely, as loops cannot be shared easily between
		329	threads anyway).
320		330
321	The default loop is the only loop that can handle C<ev_signal> and	331	The default loop is the only loop that can handle C<ev_child> watchers,
322	C<ev_child> watchers, and to do this, it always registers a handler	332	and to do this, it always registers a handler for C<SIGCHLD>. If this is
323	for C<SIGCHLD>. If this is a problem for your application you can either	333	a problem for your application you can either create a dynamic loop with
324	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	334	C<ev_loop_new> which doesn't do that, or you can simply overwrite the
325	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	335	C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
326	C<ev_default_init>.	336
		337	Example: This is the most typical usage.
		338
		339	if (!ev_default_loop (0))
		340	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		341
		342	Example: Restrict libev to the select and poll backends, and do not allow
		343	environment settings to be taken into account:
		344
		345	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
		346
		347	=item struct ev_loop *ev_loop_new (unsigned int flags)
		348
		349	This will create and initialise a new event loop object. If the loop
		350	could not be initialised, returns false.
		351
		352	Note that this function I<is> thread-safe, and one common way to use
		353	libev with threads is indeed to create one loop per thread, and using the
		354	default loop in the "main" or "initial" thread.
327		355
328	The flags argument can be used to specify special behaviour or specific	356	The flags argument can be used to specify special behaviour or specific
329	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).	357	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
330		358
331	The following flags are supported:	359	The following flags are supported:
…		…
549	If one or more of the backend flags are or'ed into the flags value,	577	If one or more of the backend flags are or'ed into the flags value,
550	then only these backends will be tried (in the reverse order as listed	578	then only these backends will be tried (in the reverse order as listed
551	here). If none are specified, all backends in C<ev_recommended_backends	579	here). If none are specified, all backends in C<ev_recommended_backends
552	()> will be tried.	580	()> will be tried.
553		581
554	Example: This is the most typical usage.
555
556	if (!ev_default_loop (0))
557	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
558
559	Example: Restrict libev to the select and poll backends, and do not allow
560	environment settings to be taken into account:
561
562	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
563
564	Example: Use whatever libev has to offer, but make sure that kqueue is
565	used if available (warning, breaks stuff, best use only with your own
566	private event loop and only if you know the OS supports your types of
567	fds):
568
569	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);
570
571	=item struct ev_loop *ev_loop_new (unsigned int flags)
572
573	Similar to C<ev_default_loop>, but always creates a new event loop that is
574	always distinct from the default loop.
575
576	Note that this function I<is> thread-safe, and one common way to use
577	libev with threads is indeed to create one loop per thread, and using the
578	default loop in the "main" or "initial" thread.
579
580	Example: Try to create a event loop that uses epoll and nothing else.	582	Example: Try to create a event loop that uses epoll and nothing else.
581		583
582	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	584	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
583	if (!epoller)	585	if (!epoller)
584	fatal ("no epoll found here, maybe it hides under your chair");	586	fatal ("no epoll found here, maybe it hides under your chair");
585		587
		588	Example: Use whatever libev has to offer, but make sure that kqueue is
		589	used if available.
		590
		591	struct ev_loop *loop = ev_loop_new (ev_recommended_backends () \| EVBACKEND_KQUEUE);
		592
586	=item ev_default_destroy ()	593	=item ev_loop_destroy (loop)
587		594
588	Destroys the default loop (frees all memory and kernel state etc.). None	595	Destroys an event loop object (frees all memory and kernel state
589	of the active event watchers will be stopped in the normal sense, so	596	etc.). None of the active event watchers will be stopped in the normal
590	e.g. C<ev_is_active> might still return true. It is your responsibility to	597	sense, so e.g. C<ev_is_active> might still return true. It is your
591	either stop all watchers cleanly yourself I<before> calling this function,	598	responsibility to either stop all watchers cleanly yourself I<before>
592	or cope with the fact afterwards (which is usually the easiest thing, you	599	calling this function, or cope with the fact afterwards (which is usually
593	can just ignore the watchers and/or C<free ()> them for example).	600	the easiest thing, you can just ignore the watchers and/or C<free ()> them
		601	for example).
594		602
595	Note that certain global state, such as signal state (and installed signal	603	Note that certain global state, such as signal state (and installed signal
596	handlers), will not be freed by this function, and related watchers (such	604	handlers), will not be freed by this function, and related watchers (such
597	as signal and child watchers) would need to be stopped manually.	605	as signal and child watchers) would need to be stopped manually.
598		606
599	In general it is not advisable to call this function except in the	607	This function is normally used on loop objects allocated by
600	rare occasion where you really need to free e.g. the signal handling	608	C<ev_loop_new>, but it can also be used on the default loop returned by
		609	C<ev_default_loop>, in which case it is not thread-safe.
		610
		611	Note that it is not advisable to call this function on the default loop
		612	except in the rare occasion where you really need to free it's resources.
601	pipe fds. If you need dynamically allocated loops it is better to use	613	If you need dynamically allocated loops it is better to use C<ev_loop_new>
602	C<ev_loop_new> and C<ev_loop_destroy>.	614	and C<ev_loop_destroy>.
603		615
604	=item ev_loop_destroy (loop)	616	=item ev_loop_fork (loop)
605		617
606	Like C<ev_default_destroy>, but destroys an event loop created by an
607	earlier call to C<ev_loop_new>.
608
609	=item ev_default_fork ()
610
611	This function sets a flag that causes subsequent C<ev_run> iterations	618	This function sets a flag that causes subsequent C<ev_run> iterations to
612	to reinitialise the kernel state for backends that have one. Despite the	619	reinitialise the kernel state for backends that have one. Despite the
613	name, you can call it anytime, but it makes most sense after forking, in	620	name, you can call it anytime, but it makes most sense after forking, in
614	the child process (or both child and parent, but that again makes little	621	the child process. You I<must> call it (or use C<EVFLAG_FORKCHECK>) in the
615	sense). You I<must> call it in the child before using any of the libev	622	child before resuming or calling C<ev_run>.
616	functions, and it will only take effect at the next C<ev_run> iteration.
617		623
618	Again, you I<have> to call it on I<any> loop that you want to re-use after	624	Again, you I<have> to call it on I<any> loop that you want to re-use after
619	a fork, I<even if you do not plan to use the loop in the parent>. This is	625	a fork, I<even if you do not plan to use the loop in the parent>. This is
620	because some kernel interfaces cough I<kqueue> cough do funny things	626	because some kernel interfaces cough I<kqueue> cough do funny things
621	during fork.	627	during fork.
…		…
626	call it at all (in fact, C<epoll> is so badly broken that it makes a	632	call it at all (in fact, C<epoll> is so badly broken that it makes a
627	difference, but libev will usually detect this case on its own and do a	633	difference, but libev will usually detect this case on its own and do a
628	costly reset of the backend).	634	costly reset of the backend).
629		635
630	The function itself is quite fast and it's usually not a problem to call	636	The function itself is quite fast and it's usually not a problem to call
631	it just in case after a fork. To make this easy, the function will fit in	637	it just in case after a fork.
632	quite nicely into a call to C<pthread_atfork>:
633		638
		639	Example: Automate calling C<ev_loop_fork> on the default loop when
		640	using pthreads.
		641
		642	static void
		643	post_fork_child (void)
		644	{
		645	ev_loop_fork (EV_DEFAULT);
		646	}
		647
		648	...
634	pthread_atfork (0, 0, ev_default_fork);	649	pthread_atfork (0, 0, post_fork_child);
635
636	=item ev_loop_fork (loop)
637
638	Like C<ev_default_fork>, but acts on an event loop created by
639	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
640	after fork that you want to re-use in the child, and how you keep track of
641	them is entirely your own problem.
642		650
643	=item int ev_is_default_loop (loop)	651	=item int ev_is_default_loop (loop)
644		652
645	Returns true when the given loop is, in fact, the default loop, and false	653	Returns true when the given loop is, in fact, the default loop, and false
646	otherwise.	654	otherwise.
…		…
908		916
909	=item ev_invoke_pending (loop)	917	=item ev_invoke_pending (loop)
910		918
911	This call will simply invoke all pending watchers while resetting their	919	This call will simply invoke all pending watchers while resetting their
912	pending state. Normally, C<ev_run> does this automatically when required,	920	pending state. Normally, C<ev_run> does this automatically when required,
913	but when overriding the invoke callback this call comes handy.	921	but when overriding the invoke callback this call comes handy. This
		922	function can be invoked from a watcher - this can be useful for example
		923	when you want to do some lengthy calculation and want to pass further
		924	event handling to another thread (you still have to make sure only one
		925	thread executes within C<ev_invoke_pending> or C<ev_run> of course).
914		926
915	=item int ev_pending_count (loop)	927	=item int ev_pending_count (loop)
916		928
917	Returns the number of pending watchers - zero indicates that no watchers	929	Returns the number of pending watchers - zero indicates that no watchers
918	are pending.	930	are pending.
…		…
990		1002
991	In the following description, uppercase C<TYPE> in names stands for the	1003	In the following description, uppercase C<TYPE> in names stands for the
992	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer	1004	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
993	watchers and C<ev_io_start> for I/O watchers.	1005	watchers and C<ev_io_start> for I/O watchers.
994		1006
995	A watcher is a structure that you create and register to record your	1007	A watcher is an opaque structure that you allocate and register to record
996	interest in some event. For instance, if you want to wait for STDIN to	1008	your interest in some event. To make a concrete example, imagine you want
997	become readable, you would create an C<ev_io> watcher for that:	1009	to wait for STDIN to become readable, you would create an C<ev_io> watcher
		1010	for that:
998		1011
999	static void my_cb (struct ev_loop loop, ev_io w, int revents)	1012	static void my_cb (struct ev_loop loop, ev_io w, int revents)
1000	{	1013	{
1001	ev_io_stop (w);	1014	ev_io_stop (w);
1002	ev_break (loop, EVBREAK_ALL);	1015	ev_break (loop, EVBREAK_ALL);
…		…
1017	stack).	1030	stack).
1018		1031
1019	Each watcher has an associated watcher structure (called C<struct ev_TYPE>	1032	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1020	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).	1033	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1021		1034
1022	Each watcher structure must be initialised by a call to C<ev_init	1035	Each watcher structure must be initialised by a call to C<ev_init (watcher
1023	(watcher *, callback)>, which expects a callback to be provided. This	1036	*, callback)>, which expects a callback to be provided. This callback is
1024	callback gets invoked each time the event occurs (or, in the case of I/O	1037	invoked each time the event occurs (or, in the case of I/O watchers, each
1025	watchers, each time the event loop detects that the file descriptor given	1038	time the event loop detects that the file descriptor given is readable
1026	is readable and/or writable).	1039	and/or writable).
1027		1040
1028	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>	1041	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1029	macro to configure it, with arguments specific to the watcher type. There	1042	macro to configure it, with arguments specific to the watcher type. There
1030	is also a macro to combine initialisation and setting in one call: C<<	1043	is also a macro to combine initialisation and setting in one call: C<<
1031	ev_TYPE_init (watcher *, callback, ...) >>.	1044	ev_TYPE_init (watcher *, callback, ...) >>.
…		…
1099	=item C<EV_FORK>	1112	=item C<EV_FORK>
1100		1113
1101	The event loop has been resumed in the child process after fork (see	1114	The event loop has been resumed in the child process after fork (see
1102	C<ev_fork>).	1115	C<ev_fork>).
1103		1116
		1117	=item C<EV_CLEANUP>
		1118
		1119	The event loop is about to be destroyed (see C<ev_cleanup>).
		1120
1104	=item C<EV_ASYNC>	1121	=item C<EV_ASYNC>
1105		1122
1106	The given async watcher has been asynchronously notified (see C<ev_async>).	1123	The given async watcher has been asynchronously notified (see C<ev_async>).
1107		1124
1108	=item C<EV_CUSTOM>	1125	=item C<EV_CUSTOM>
…		…
1126	example it might indicate that a fd is readable or writable, and if your	1143	example it might indicate that a fd is readable or writable, and if your
1127	callbacks is well-written it can just attempt the operation and cope with	1144	callbacks is well-written it can just attempt the operation and cope with
1128	the error from read() or write(). This will not work in multi-threaded	1145	the error from read() or write(). This will not work in multi-threaded
1129	programs, though, as the fd could already be closed and reused for another	1146	programs, though, as the fd could already be closed and reused for another
1130	thing, so beware.	1147	thing, so beware.
		1148
		1149	=back
		1150
		1151	=head2 WATCHER STATES
		1152
		1153	There are various watcher states mentioned throughout this manual -
		1154	active, pending and so on. In this section these states and the rules to
		1155	transition between them will be described in more detail - and while these
		1156	rules might look complicated, they usually do "the right thing".
		1157
		1158	=over 4
		1159
		1160	=item initialiased
		1161
		1162	Before a watcher can be registered with the event looop it has to be
		1163	initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
		1164	C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
		1165
		1166	In this state it is simply some block of memory that is suitable for use
		1167	in an event loop. It can be moved around, freed, reused etc. at will.
		1168
		1169	=item started/running/active
		1170
		1171	Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
		1172	property of the event loop, and is actively waiting for events. While in
		1173	this state it cannot be accessed (except in a few documented ways), moved,
		1174	freed or anything else - the only legal thing is to keep a pointer to it,
		1175	and call libev functions on it that are documented to work on active watchers.
		1176
		1177	=item pending
		1178
		1179	If a watcher is active and libev determines that an event it is interested
		1180	in has occurred (such as a timer expiring), it will become pending. It will
		1181	stay in this pending state until either it is stopped or its callback is
		1182	about to be invoked, so it is not normally pending inside the watcher
		1183	callback.
		1184
		1185	The watcher might or might not be active while it is pending (for example,
		1186	an expired non-repeating timer can be pending but no longer active). If it
		1187	is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
		1188	but it is still property of the event loop at this time, so cannot be
		1189	moved, freed or reused. And if it is active the rules described in the
		1190	previous item still apply.
		1191
		1192	It is also possible to feed an event on a watcher that is not active (e.g.
		1193	via C<ev_feed_event>), in which case it becomes pending without being
		1194	active.
		1195
		1196	=item stopped
		1197
		1198	A watcher can be stopped implicitly by libev (in which case it might still
		1199	be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
		1200	latter will clear any pending state the watcher might be in, regardless
		1201	of whether it was active or not, so stopping a watcher explicitly before
		1202	freeing it is often a good idea.
		1203
		1204	While stopped (and not pending) the watcher is essentially in the
		1205	initialised state, that is it can be reused, moved, modified in any way
		1206	you wish.
1131		1207
1132	=back	1208	=back
1133		1209
1134	=head2 GENERIC WATCHER FUNCTIONS	1210	=head2 GENERIC WATCHER FUNCTIONS
1135		1211
…		…
3008	disadvantage of having to use multiple event loops (which do not support	3084	disadvantage of having to use multiple event loops (which do not support
3009	signal watchers).	3085	signal watchers).
3010		3086
3011	When this is not possible, or you want to use the default loop for	3087	When this is not possible, or you want to use the default loop for
3012	other reasons, then in the process that wants to start "fresh", call	3088	other reasons, then in the process that wants to start "fresh", call
3013	C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying	3089	C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
3014	the default loop will "orphan" (not stop) all registered watchers, so you	3090	Destroying the default loop will "orphan" (not stop) all registered
3015	have to be careful not to execute code that modifies those watchers. Note	3091	watchers, so you have to be careful not to execute code that modifies
3016	also that in that case, you have to re-register any signal watchers.	3092	those watchers. Note also that in that case, you have to re-register any
		3093	signal watchers.
3017		3094
3018	=head3 Watcher-Specific Functions and Data Members	3095	=head3 Watcher-Specific Functions and Data Members
3019		3096
3020	=over 4	3097	=over 4
3021		3098
3022	=item ev_fork_init (ev_signal *, callback)	3099	=item ev_fork_init (ev_fork *, callback)
3023		3100
3024	Initialises and configures the fork watcher - it has no parameters of any	3101	Initialises and configures the fork watcher - it has no parameters of any
3025	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,	3102	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
3026	believe me.	3103	really.
3027		3104
3028	=back	3105	=back
		3106
		3107
		3108	=head2 C<ev_cleanup> - even the best things end
		3109
		3110	Cleanup watchers are called just before the event loop is being destroyed
		3111	by a call to C<ev_loop_destroy>.
		3112
		3113	While there is no guarantee that the event loop gets destroyed, cleanup
		3114	watchers provide a convenient method to install cleanup hooks for your
		3115	program, worker threads and so on - you just to make sure to destroy the
		3116	loop when you want them to be invoked.
		3117
		3118	Cleanup watchers are invoked in the same way as any other watcher. Unlike
		3119	all other watchers, they do not keep a reference to the event loop (which
		3120	makes a lot of sense if you think about it). Like all other watchers, you
		3121	can call libev functions in the callback, except C<ev_cleanup_start>.
		3122
		3123	=head3 Watcher-Specific Functions and Data Members
		3124
		3125	=over 4
		3126
		3127	=item ev_cleanup_init (ev_cleanup *, callback)
		3128
		3129	Initialises and configures the cleanup watcher - it has no parameters of
		3130	any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
		3131	pointless, I assure you.
		3132
		3133	=back
		3134
		3135	Example: Register an atexit handler to destroy the default loop, so any
		3136	cleanup functions are called.
		3137
		3138	static void
		3139	program_exits (void)
		3140	{
		3141	ev_loop_destroy (EV_DEFAULT_UC);
		3142	}
		3143
		3144	...
		3145	atexit (program_exits);
3029		3146
3030		3147
3031	=head2 C<ev_async> - how to wake up an event loop	3148	=head2 C<ev_async> - how to wake up an event loop
3032		3149
3033	In general, you cannot use an C<ev_run> from multiple threads or other	3150	In general, you cannot use an C<ev_run> from multiple threads or other
…		…
4467	=head3 C<kqueue> is buggy	4584	=head3 C<kqueue> is buggy
4468		4585
4469	The kqueue syscall is broken in all known versions - most versions support	4586	The kqueue syscall is broken in all known versions - most versions support
4470	only sockets, many support pipes.	4587	only sockets, many support pipes.
4471		4588
4472	Libev tries to work around this by not using C<kqueue> by default on	4589	Libev tries to work around this by not using C<kqueue> by default on this
4473	this rotten platform, but of course you can still ask for it when creating	4590	rotten platform, but of course you can still ask for it when creating a
4474	a loop.	4591	loop - embedding a socket-only kqueue loop into a select-based one is
		4592	probably going to work well.
4475		4593
4476	=head3 C<poll> is buggy	4594	=head3 C<poll> is buggy
4477		4595
4478	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>	4596	Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
4479	implementation by something calling C<kqueue> internally around the 10.5.6	4597	implementation by something calling C<kqueue> internally around the 10.5.6
…		…
4498		4616
4499	=head3 C<errno> reentrancy	4617	=head3 C<errno> reentrancy
4500		4618
4501	The default compile environment on Solaris is unfortunately so	4619	The default compile environment on Solaris is unfortunately so
4502	thread-unsafe that you can't even use components/libraries compiled	4620	thread-unsafe that you can't even use components/libraries compiled
4503	without C<-D_REENTRANT> (as long as they use C<errno>), which, of course,	4621	without C<-D_REENTRANT> in a threaded program, which, of course, isn't
4504	isn't defined by default.	4622	defined by default. A valid, if stupid, implementation choice.
4505		4623
4506	If you want to use libev in threaded environments you have to make sure	4624	If you want to use libev in threaded environments you have to make sure
4507	it's compiled with C<_REENTRANT> defined.	4625	it's compiled with C<_REENTRANT> defined.
4508		4626
4509	=head3 Event port backend	4627	=head3 Event port backend
4510		4628
4511	The scalable event interface for Solaris is called "event ports". Unfortunately,	4629	The scalable event interface for Solaris is called "event
4512	this mechanism is very buggy. If you run into high CPU usage, your program	4630	ports". Unfortunately, this mechanism is very buggy in all major
		4631	releases. If you run into high CPU usage, your program freezes or you get
4513	freezes or you get a large number of spurious wakeups, make sure you have	4632	a large number of spurious wakeups, make sure you have all the relevant
4514	all the relevant and latest kernel patches applied. No, I don't know which	4633	and latest kernel patches applied. No, I don't know which ones, but there
4515	ones, but there are multiple ones.	4634	are multiple ones to apply, and afterwards, event ports actually work
		4635	great.
4516		4636
4517	If you can't get it to work, you can try running the program by setting	4637	If you can't get it to work, you can try running the program by setting
4518	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and	4638	the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
4519	C<select> backends.	4639	C<select> backends.
4520		4640
4521	=head2 AIX POLL BUG	4641	=head2 AIX POLL BUG
4522		4642
4523	AIX unfortunately has a broken C<poll.h> header. Libev works around	4643	AIX unfortunately has a broken C<poll.h> header. Libev works around
4524	this by trying to avoid the poll backend altogether (i.e. it's not even	4644	this by trying to avoid the poll backend altogether (i.e. it's not even
4525	compiled in), which normally isn't a big problem as C<select> works fine	4645	compiled in), which normally isn't a big problem as C<select> works fine
4526	with large bitsets, and AIX is dead anyway.	4646	with large bitsets on AIX, and AIX is dead anyway.
4527		4647
4528	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS	4648	=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
4529		4649
4530	=head3 General issues	4650	=head3 General issues
4531		4651
…		…
4637	structure (guaranteed by POSIX but not by ISO C for example), but it also	4757	structure (guaranteed by POSIX but not by ISO C for example), but it also
4638	assumes that the same (machine) code can be used to call any watcher	4758	assumes that the same (machine) code can be used to call any watcher
4639	callback: The watcher callbacks have different type signatures, but libev	4759	callback: The watcher callbacks have different type signatures, but libev
4640	calls them using an C<ev_watcher *> internally.	4760	calls them using an C<ev_watcher *> internally.
4641		4761
		4762	=item pointer accesses must be thread-atomic
		4763
		4764	Accessing a pointer value must be atomic, it must both be readable and
		4765	writable in one piece - this is the case on all current architectures.
		4766
4642	=item C<sig_atomic_t volatile> must be thread-atomic as well	4767	=item C<sig_atomic_t volatile> must be thread-atomic as well
4643		4768
4644	The type C<sig_atomic_t volatile> (or whatever is defined as	4769	The type C<sig_atomic_t volatile> (or whatever is defined as
4645	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different	4770	C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
4646	threads. This is not part of the specification for C<sig_atomic_t>, but is	4771	threads. This is not part of the specification for C<sig_atomic_t>, but is
…		…
4752	=back	4877	=back
4753		4878
4754		4879
4755	=head1 PORTING FROM LIBEV 3.X TO 4.X	4880	=head1 PORTING FROM LIBEV 3.X TO 4.X
4756		4881
4757	The major version 4 introduced some minor incompatible changes to the API.	4882	The major version 4 introduced some incompatible changes to the API.
4758		4883
4759	At the moment, the C<ev.h> header file tries to implement superficial	4884	At the moment, the C<ev.h> header file provides compatibility definitions
4760	compatibility, so most programs should still compile. Those might be	4885	for all changes, so most programs should still compile. The compatibility
4761	removed in later versions of libev, so better update early than late.	4886	layer might be removed in later versions of libev, so better update to the
		4887	new API early than late.
4762		4888
4763	=over 4	4889	=over 4
		4890
		4891	=item C<EV_COMPAT3> backwards compatibility mechanism
		4892
		4893	The backward compatibility mechanism can be controlled by
		4894	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
		4895	section.
		4896
		4897	=item C<ev_default_destroy> and C<ev_default_fork> have been removed
		4898
		4899	These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
		4900
		4901	ev_loop_destroy (EV_DEFAULT_UC);
		4902	ev_loop_fork (EV_DEFAULT);
4764		4903
4765	=item function/symbol renames	4904	=item function/symbol renames
4766		4905
4767	A number of functions and symbols have been renamed:	4906	A number of functions and symbols have been renamed:
4768		4907
…		…
4787	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme	4926	ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
4788	as all other watcher types. Note that C<ev_loop_fork> is still called	4927	as all other watcher types. Note that C<ev_loop_fork> is still called
4789	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>	4928	C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4790	typedef.	4929	typedef.
4791		4930
4792	=item C<EV_COMPAT3> backwards compatibility mechanism
4793
4794	The backward compatibility mechanism can be controlled by
4795	C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4796	section.
4797
4798	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>	4931	=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
4799		4932
4800	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different	4933	The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4801	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile	4934	mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
4802	and work, but the library code will of course be larger.	4935	and work, but the library code will of course be larger.
…		…
4808		4941
4809	=over 4	4942	=over 4
4810		4943
4811	=item active	4944	=item active
4812		4945
4813	A watcher is active as long as it has been started (has been attached to	4946	A watcher is active as long as it has been started and not yet stopped.
4814	an event loop) but not yet stopped (disassociated from the event loop).	4947	See L<WATCHER STATES> for details.
4815		4948
4816	=item application	4949	=item application
4817		4950
4818	In this document, an application is whatever is using libev.	4951	In this document, an application is whatever is using libev.
		4952
		4953	=item backend
		4954
		4955	The part of the code dealing with the operating system interfaces.
4819		4956
4820	=item callback	4957	=item callback
4821		4958
4822	The address of a function that is called when some event has been	4959	The address of a function that is called when some event has been
4823	detected. Callbacks are being passed the event loop, the watcher that	4960	detected. Callbacks are being passed the event loop, the watcher that
4824	received the event, and the actual event bitset.	4961	received the event, and the actual event bitset.
4825		4962
4826	=item callback invocation	4963	=item callback/watcher invocation
4827		4964
4828	The act of calling the callback associated with a watcher.	4965	The act of calling the callback associated with a watcher.
4829		4966
4830	=item event	4967	=item event
4831		4968
…		…
4850	The model used to describe how an event loop handles and processes	4987	The model used to describe how an event loop handles and processes
4851	watchers and events.	4988	watchers and events.
4852		4989
4853	=item pending	4990	=item pending
4854		4991
4855	A watcher is pending as soon as the corresponding event has been detected,	4992	A watcher is pending as soon as the corresponding event has been
4856	and stops being pending as soon as the watcher will be invoked or its	4993	detected. See L<WATCHER STATES> for details.
4857	pending status is explicitly cleared by the application.
4858
4859	A watcher can be pending, but not active. Stopping a watcher also clears
4860	its pending status.
4861		4994
4862	=item real time	4995	=item real time
4863		4996
4864	The physical time that is observed. It is apparently strictly monotonic :)	4997	The physical time that is observed. It is apparently strictly monotonic :)
4865		4998
…		…
4872	=item watcher	5005	=item watcher
4873		5006
4874	A data structure that describes interest in certain events. Watchers need	5007	A data structure that describes interest in certain events. Watchers need
4875	to be started (attached to an event loop) before they can receive events.	5008	to be started (attached to an event loop) before they can receive events.
4876		5009
4877	=item watcher invocation
4878
4879	The act of calling the callback associated with a watcher.
4880
4881	=back	5010	=back
4882		5011
4883	=head1 AUTHOR	5012	=head1 AUTHOR
4884		5013
4885	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.	5014	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
		5015	Magnusson and Emanuele Giaquinta.
4886		5016

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Comparing libev/ev.pod (file contents): Revision 1.310 by root, Thu Oct 21 12:32:47 2010 UTC vs. Revision 1.333 by root, Mon Oct 25 09:31:47 2010 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.310 by root, Thu Oct 21 12:32:47 2010 UTC vs.
Revision 1.333 by root, Mon Oct 25 09:31:47 2010 UTC