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

Comparing libev/ev.pod (file contents):
Revision 1.1 by root, Mon Nov 12 07:58:13 2007 UTC vs.
Revision 1.38 by root, Sat Nov 24 09:48:38 2007 UTC

…		…
8		8
9	=head1 DESCRIPTION	9	=head1 DESCRIPTION
10		10
11	Libev is an event loop: you register interest in certain events (such as a	11	Libev is an event loop: you register interest in certain events (such as a
12	file descriptor being readable or a timeout occuring), and it will manage	12	file descriptor being readable or a timeout occuring), and it will manage
13	these event sources and provide your program events.	13	these event sources and provide your program with events.
14		14
15	To do this, it must take more or less complete control over your process	15	To do this, it must take more or less complete control over your process
16	(or thread) by executing the I<event loop> handler, and will then	16	(or thread) by executing the I<event loop> handler, and will then
17	communicate events via a callback mechanism.	17	communicate events via a callback mechanism.
18		18
…		…
25		25
26	Libev supports select, poll, the linux-specific epoll and the bsd-specific	26	Libev supports select, poll, the linux-specific epoll and the bsd-specific
27	kqueue mechanisms for file descriptor events, relative timers, absolute	27	kqueue mechanisms for file descriptor events, relative timers, absolute
28	timers with customised rescheduling, signal events, process status change	28	timers with customised rescheduling, signal events, process status change
29	events (related to SIGCHLD), and event watchers dealing with the event	29	events (related to SIGCHLD), and event watchers dealing with the event
30	loop mechanism itself (idle, prepare and check watchers).	30	loop mechanism itself (idle, prepare and check watchers). It also is quite
		31	fast (see this L<benchmark\|http://libev.schmorp.de/bench.html> comparing
		32	it to libevent for example).
31		33
32	=head1 CONVENTIONS	34	=head1 CONVENTIONS
33		35
34	Libev is very configurable. In this manual the default configuration	36	Libev is very configurable. In this manual the default configuration
35	will be described, which supports multiple event loops. For more info	37	will be described, which supports multiple event loops. For more info
36	about various configuraiton options please have a look at the file	38	about various configuration options please have a look at the file
37	F<README.embed> in the libev distribution. If libev was configured without	39	F<README.embed> in the libev distribution. If libev was configured without
38	support for multiple event loops, then all functions taking an initial	40	support for multiple event loops, then all functions taking an initial
39	argument of name C<loop> (which is always of type C<struct ev_loop *>)	41	argument of name C<loop> (which is always of type C<struct ev_loop *>)
40	will not have this argument.	42	will not have this argument.
41		43
42	=head1 TIME AND OTHER GLOBAL FUNCTIONS	44	=head1 TIME REPRESENTATION
43		45
44	Libev represents time as a single floating point number. This type is	46	Libev represents time as a single floating point number, representing the
		47	(fractional) number of seconds since the (POSIX) epoch (somewhere near
		48	the beginning of 1970, details are complicated, don't ask). This type is
45	called C<ev_tstamp>, which is what you should use too. It usually aliases	49	called C<ev_tstamp>, which is what you should use too. It usually aliases
46	to the double type in C.	50	to the C<double> type in C, and when you need to do any calculations on
		51	it, you should treat it as such.
		52
		53
		54	=head1 GLOBAL FUNCTIONS
		55
		56	These functions can be called anytime, even before initialising the
		57	library in any way.
47		58
48	=over 4	59	=over 4
49		60
50	=item ev_tstamp ev_time ()	61	=item ev_tstamp ev_time ()
51		62
52	Returns the current time as libev would use it.	63	Returns the current time as libev would use it. Please note that the
		64	C<ev_now> function is usually faster and also often returns the timestamp
		65	you actually want to know.
53		66
54	=item int ev_version_major ()	67	=item int ev_version_major ()
55		68
56	=item int ev_version_minor ()	69	=item int ev_version_minor ()
57		70
…		…
59	you linked against by calling the functions C<ev_version_major> and	72	you linked against by calling the functions C<ev_version_major> and
60	C<ev_version_minor>. If you want, you can compare against the global	73	C<ev_version_minor>. If you want, you can compare against the global
61	symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the	74	symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the
62	version of the library your program was compiled against.	75	version of the library your program was compiled against.
63		76
64	Usually, its a good idea to terminate if the major versions mismatch,	77	Usually, it's a good idea to terminate if the major versions mismatch,
65	as this indicates an incompatible change. Minor versions are usually	78	as this indicates an incompatible change. Minor versions are usually
66	compatible to older versions, so a larger minor version alone is usually	79	compatible to older versions, so a larger minor version alone is usually
67	not a problem.	80	not a problem.
68		81
		82	Example: make sure we haven't accidentally been linked against the wrong
		83	version:
		84
		85	assert (("libev version mismatch",
		86	ev_version_major () == EV_VERSION_MAJOR
		87	&& ev_version_minor () >= EV_VERSION_MINOR));
		88
		89	=item unsigned int ev_supported_backends ()
		90
		91	Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*>
		92	value) compiled into this binary of libev (independent of their
		93	availability on the system you are running on). See C<ev_default_loop> for
		94	a description of the set values.
		95
		96	Example: make sure we have the epoll method, because yeah this is cool and
		97	a must have and can we have a torrent of it please!!!11
		98
		99	assert (("sorry, no epoll, no sex",
		100	ev_supported_backends () & EVBACKEND_EPOLL));
		101
		102	=item unsigned int ev_recommended_backends ()
		103
		104	Return the set of all backends compiled into this binary of libev and also
		105	recommended for this platform. This set is often smaller than the one
		106	returned by C<ev_supported_backends>, as for example kqueue is broken on
		107	most BSDs and will not be autodetected unless you explicitly request it
		108	(assuming you know what you are doing). This is the set of backends that
		109	libev will probe for if you specify no backends explicitly.
		110
		111	=item unsigned int ev_embeddable_backends ()
		112
		113	Returns the set of backends that are embeddable in other event loops. This
		114	is the theoretical, all-platform, value. To find which backends
		115	might be supported on the current system, you would need to look at
		116	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for
		117	recommended ones.
		118
		119	See the description of C<ev_embed> watchers for more info.
		120
69	=item ev_set_allocator (void (cb)(void *ptr, long size))	121	=item ev_set_allocator (void (cb)(void *ptr, long size))
70		122
71	Sets the allocation function to use (the prototype is similar to the	123	Sets the allocation function to use (the prototype is similar to the
72	realloc function). It is used to allocate and free memory (no surprises	124	realloc C function, the semantics are identical). It is used to allocate
73	here). If it returns zero when memory needs to be allocated, the library	125	and free memory (no surprises here). If it returns zero when memory
74	might abort or take some potentially destructive action. The default is	126	needs to be allocated, the library might abort or take some potentially
75	your system realloc function.	127	destructive action. The default is your system realloc function.
76		128
77	You could override this function in high-availability programs to, say,	129	You could override this function in high-availability programs to, say,
78	free some memory if it cannot allocate memory, to use a special allocator,	130	free some memory if it cannot allocate memory, to use a special allocator,
79	or even to sleep a while and retry until some memory is available.	131	or even to sleep a while and retry until some memory is available.
		132
		133	Example: replace the libev allocator with one that waits a bit and then
		134	retries: better than mine).
		135
		136	static void *
		137	persistent_realloc (void *ptr, long size)
		138	{
		139	for (;;)
		140	{
		141	void *newptr = realloc (ptr, size);
		142
		143	if (newptr)
		144	return newptr;
		145
		146	sleep (60);
		147	}
		148	}
		149
		150	...
		151	ev_set_allocator (persistent_realloc);
80		152
81	=item ev_set_syserr_cb (void (cb)(const char msg));	153	=item ev_set_syserr_cb (void (cb)(const char msg));
82		154
83	Set the callback function to call on a retryable syscall error (such	155	Set the callback function to call on a retryable syscall error (such
84	as failed select, poll, epoll_wait). The message is a printable string	156	as failed select, poll, epoll_wait). The message is a printable string
85	indicating the system call or subsystem causing the problem. If this	157	indicating the system call or subsystem causing the problem. If this
86	callback is set, then libev will expect it to remedy the sitution, no	158	callback is set, then libev will expect it to remedy the sitution, no
87	matter what, when it returns. That is, libev will geenrally retry the	159	matter what, when it returns. That is, libev will generally retry the
88	requested operation, or, if the condition doesn't go away, do bad stuff	160	requested operation, or, if the condition doesn't go away, do bad stuff
89	(such as abort).	161	(such as abort).
		162
		163	Example: do the same thing as libev does internally:
		164
		165	static void
		166	fatal_error (const char *msg)
		167	{
		168	perror (msg);
		169	abort ();
		170	}
		171
		172	...
		173	ev_set_syserr_cb (fatal_error);
90		174
91	=back	175	=back
92		176
93	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	177	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP
94		178
95	An event loop is described by a C<struct ev_loop *>. The library knows two	179	An event loop is described by a C<struct ev_loop *>. The library knows two
96	types of such loops, the I<default> loop, which supports signals and child	180	types of such loops, the I<default> loop, which supports signals and child
97	events, and dynamically created loops which do not.	181	events, and dynamically created loops which do not.
98		182
99	If you use threads, a common model is to run the default event loop	183	If you use threads, a common model is to run the default event loop
100	in your main thread (or in a separate thrad) and for each thread you	184	in your main thread (or in a separate thread) and for each thread you
101	create, you also create another event loop. Libev itself does no lockign	185	create, you also create another event loop. Libev itself does no locking
102	whatsoever, so if you mix calls to different event loops, make sure you	186	whatsoever, so if you mix calls to the same event loop in different
103	lock (this is usually a bad idea, though, even if done right).	187	threads, make sure you lock (this is usually a bad idea, though, even if
		188	done correctly, because it's hideous and inefficient).
104		189
105	=over 4	190	=over 4
106		191
107	=item struct ev_loop *ev_default_loop (unsigned int flags)	192	=item struct ev_loop *ev_default_loop (unsigned int flags)
108		193
109	This will initialise the default event loop if it hasn't been initialised	194	This will initialise the default event loop if it hasn't been initialised
110	yet and return it. If the default loop could not be initialised, returns	195	yet and return it. If the default loop could not be initialised, returns
111	false. If it already was initialised it simply returns it (and ignores the	196	false. If it already was initialised it simply returns it (and ignores the
112	flags).	197	flags. If that is troubling you, check C<ev_backend ()> afterwards).
113		198
114	If you don't know what event loop to use, use the one returned from this	199	If you don't know what event loop to use, use the one returned from this
115	function.	200	function.
116		201
117	The flags argument can be used to specify special behaviour or specific	202	The flags argument can be used to specify special behaviour or specific
118	backends to use, and is usually specified as 0 (or EVFLAG_AUTO)	203	backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
119		204
120	It supports the following flags:	205	The following flags are supported:
121		206
122	=over 4	207	=over 4
123		208
124	=item EVFLAG_AUTO	209	=item C<EVFLAG_AUTO>
125		210
126	The default flags value. Use this if you have no clue (its the right	211	The default flags value. Use this if you have no clue (it's the right
127	thing, believe me).	212	thing, believe me).
128		213
129	=item EVFLAG_NOENV	214	=item C<EVFLAG_NOENV>
130		215
131	If this flag bit is ored into the flag value then libev will I<not> look	216	If this flag bit is ored into the flag value (or the program runs setuid
132	at the environment variable C<LIBEV_FLAGS>. Otherwise (the default), this	217	or setgid) then libev will I<not> look at the environment variable
133	environment variable will override the flags completely. This is useful	218	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
		219	override the flags completely if it is found in the environment. This is
134	to try out specific backends to tets their performance, or to work around	220	useful to try out specific backends to test their performance, or to work
135	bugs.	221	around bugs.
136		222
137	=item EVMETHOD_SELECT portable select backend	223	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
138		224
139	=item EVMETHOD_POLL poll backend (everywhere except windows)	225	This is your standard select(2) backend. Not I<completely> standard, as
		226	libev tries to roll its own fd_set with no limits on the number of fds,
		227	but if that fails, expect a fairly low limit on the number of fds when
		228	using this backend. It doesn't scale too well (O(highest_fd)), but its usually
		229	the fastest backend for a low number of fds.
140		230
141	=item EVMETHOD_EPOLL linux only	231	=item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows)
142		232
143	=item EVMETHOD_KQUEUE some bsds only	233	And this is your standard poll(2) backend. It's more complicated than
		234	select, but handles sparse fds better and has no artificial limit on the
		235	number of fds you can use (except it will slow down considerably with a
		236	lot of inactive fds). It scales similarly to select, i.e. O(total_fds).
144		237
145	=item EVMETHOD_DEVPOLL solaris 8 only	238	=item C<EVBACKEND_EPOLL> (value 4, Linux)
146		239
147	=item EVMETHOD_PORT solaris 10 only	240	For few fds, this backend is a bit little slower than poll and select,
		241	but it scales phenomenally better. While poll and select usually scale like
		242	O(total_fds) where n is the total number of fds (or the highest fd), epoll scales
		243	either O(1) or O(active_fds).
		244
		245	While stopping and starting an I/O watcher in the same iteration will
		246	result in some caching, there is still a syscall per such incident
		247	(because the fd could point to a different file description now), so its
		248	best to avoid that. Also, dup()ed file descriptors might not work very
		249	well if you register events for both fds.
		250
		251	Please note that epoll sometimes generates spurious notifications, so you
		252	need to use non-blocking I/O or other means to avoid blocking when no data
		253	(or space) is available.
		254
		255	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
		256
		257	Kqueue deserves special mention, as at the time of this writing, it
		258	was broken on all BSDs except NetBSD (usually it doesn't work with
		259	anything but sockets and pipes, except on Darwin, where of course its
		260	completely useless). For this reason its not being "autodetected"
		261	unless you explicitly specify it explicitly in the flags (i.e. using
		262	C<EVBACKEND_KQUEUE>).
		263
		264	It scales in the same way as the epoll backend, but the interface to the
		265	kernel is more efficient (which says nothing about its actual speed, of
		266	course). While starting and stopping an I/O watcher does not cause an
		267	extra syscall as with epoll, it still adds up to four event changes per
		268	incident, so its best to avoid that.
		269
		270	=item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8)
		271
		272	This is not implemented yet (and might never be).
		273
		274	=item C<EVBACKEND_PORT> (value 32, Solaris 10)
		275
		276	This uses the Solaris 10 port mechanism. As with everything on Solaris,
		277	it's really slow, but it still scales very well (O(active_fds)).
		278
		279	Please note that solaris ports can result in a lot of spurious
		280	notifications, so you need to use non-blocking I/O or other means to avoid
		281	blocking when no data (or space) is available.
		282
		283	=item C<EVBACKEND_ALL>
		284
		285	Try all backends (even potentially broken ones that wouldn't be tried
		286	with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as
		287	C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.
		288
		289	=back
148		290
149	If one or more of these are ored into the flags value, then only these	291	If one or more of these are ored into the flags value, then only these
150	backends will be tried (in the reverse order as given here). If one are	292	backends will be tried (in the reverse order as given here). If none are
151	specified, any backend will do.	293	specified, most compiled-in backend will be tried, usually in reverse
		294	order of their flag values :)
152		295
153	=back	296	The most typical usage is like this:
		297
		298	if (!ev_default_loop (0))
		299	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
		300
		301	Restrict libev to the select and poll backends, and do not allow
		302	environment settings to be taken into account:
		303
		304	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
		305
		306	Use whatever libev has to offer, but make sure that kqueue is used if
		307	available (warning, breaks stuff, best use only with your own private
		308	event loop and only if you know the OS supports your types of fds):
		309
		310	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);
154		311
155	=item struct ev_loop *ev_loop_new (unsigned int flags)	312	=item struct ev_loop *ev_loop_new (unsigned int flags)
156		313
157	Similar to C<ev_default_loop>, but always creates a new event loop that is	314	Similar to C<ev_default_loop>, but always creates a new event loop that is
158	always distinct from the default loop. Unlike the default loop, it cannot	315	always distinct from the default loop. Unlike the default loop, it cannot
159	handle signal and child watchers, and attempts to do so will be greeted by	316	handle signal and child watchers, and attempts to do so will be greeted by
160	undefined behaviour (or a failed assertion if assertions are enabled).	317	undefined behaviour (or a failed assertion if assertions are enabled).
161		318
		319	Example: try to create a event loop that uses epoll and nothing else.
		320
		321	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
		322	if (!epoller)
		323	fatal ("no epoll found here, maybe it hides under your chair");
		324
162	=item ev_default_destroy ()	325	=item ev_default_destroy ()
163		326
164	Destroys the default loop again (frees all memory and kernel state	327	Destroys the default loop again (frees all memory and kernel state
165	etc.). This stops all registered event watchers (by not touching them in	328	etc.). None of the active event watchers will be stopped in the normal
166	any way whatsoever, although you cnanot rely on this :).	329	sense, so e.g. C<ev_is_active> might still return true. It is your
		330	responsibility to either stop all watchers cleanly yoursef I<before>
		331	calling this function, or cope with the fact afterwards (which is usually
		332	the easiest thing, youc na just ignore the watchers and/or C<free ()> them
		333	for example).
167		334
168	=item ev_loop_destroy (loop)	335	=item ev_loop_destroy (loop)
169		336
170	Like C<ev_default_destroy>, but destroys an event loop created by an	337	Like C<ev_default_destroy>, but destroys an event loop created by an
171	earlier call to C<ev_loop_new>.	338	earlier call to C<ev_loop_new>.
…		…
175	This function reinitialises the kernel state for backends that have	342	This function reinitialises the kernel state for backends that have
176	one. Despite the name, you can call it anytime, but it makes most sense	343	one. Despite the name, you can call it anytime, but it makes most sense
177	after forking, in either the parent or child process (or both, but that	344	after forking, in either the parent or child process (or both, but that
178	again makes little sense).	345	again makes little sense).
179		346
180	You I<must> call this function after forking if and only if you want to	347	You I<must> call this function in the child process after forking if and
181	use the event library in both processes. If you just fork+exec, you don't	348	only if you want to use the event library in both processes. If you just
182	have to call it.	349	fork+exec, you don't have to call it.
183		350
184	The function itself is quite fast and its usually not a problem to call	351	The function itself is quite fast and it's usually not a problem to call
185	it just in case after a fork. To make this easy, the function will fit in	352	it just in case after a fork. To make this easy, the function will fit in
186	quite nicely into a call to C<pthread_atfork>:	353	quite nicely into a call to C<pthread_atfork>:
187		354
188	pthread_atfork (0, 0, ev_default_fork);	355	pthread_atfork (0, 0, ev_default_fork);
		356
		357	At the moment, C<EVBACKEND_SELECT> and C<EVBACKEND_POLL> are safe to use
		358	without calling this function, so if you force one of those backends you
		359	do not need to care.
189		360
190	=item ev_loop_fork (loop)	361	=item ev_loop_fork (loop)
191		362
192	Like C<ev_default_fork>, but acts on an event loop created by	363	Like C<ev_default_fork>, but acts on an event loop created by
193	C<ev_loop_new>. Yes, you have to call this on every allocated event loop	364	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
194	after fork, and how you do this is entirely your own problem.	365	after fork, and how you do this is entirely your own problem.
195		366
196	=item unsigned int ev_method (loop)	367	=item unsigned int ev_backend (loop)
197		368
198	Returns one of the C<EVMETHOD_*> flags indicating the event backend in	369	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
199	use.	370	use.
200		371
201	=item ev_tstamp = ev_now (loop)	372	=item ev_tstamp ev_now (loop)
202		373
203	Returns the current "event loop time", which is the time the event loop	374	Returns the current "event loop time", which is the time the event loop
204	got events and started processing them. This timestamp does not change	375	received events and started processing them. This timestamp does not
205	as long as callbacks are being processed, and this is also the base time	376	change as long as callbacks are being processed, and this is also the base
206	used for relative timers. You can treat it as the timestamp of the event	377	time used for relative timers. You can treat it as the timestamp of the
207	occuring (or more correctly, the mainloop finding out about it).	378	event occuring (or more correctly, libev finding out about it).
208		379
209	=item ev_loop (loop, int flags)	380	=item ev_loop (loop, int flags)
210		381
211	Finally, this is it, the event handler. This function usually is called	382	Finally, this is it, the event handler. This function usually is called
212	after you initialised all your watchers and you want to start handling	383	after you initialised all your watchers and you want to start handling
213	events.	384	events.
214		385
215	If the flags argument is specified as 0, it will not return until either	386	If the flags argument is specified as C<0>, it will not return until
216	no event watchers are active anymore or C<ev_unloop> was called.	387	either no event watchers are active anymore or C<ev_unloop> was called.
		388
		389	Please note that an explicit C<ev_unloop> is usually better than
		390	relying on all watchers to be stopped when deciding when a program has
		391	finished (especially in interactive programs), but having a program that
		392	automatically loops as long as it has to and no longer by virtue of
		393	relying on its watchers stopping correctly is a thing of beauty.
217		394
218	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	395	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle
219	those events and any outstanding ones, but will not block your process in	396	those events and any outstanding ones, but will not block your process in
220	case there are no events.	397	case there are no events and will return after one iteration of the loop.
221		398
222	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	399	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if
223	neccessary) and will handle those and any outstanding ones. It will block	400	neccessary) and will handle those and any outstanding ones. It will block
224	your process until at least one new event arrives.	401	your process until at least one new event arrives, and will return after
		402	one iteration of the loop. This is useful if you are waiting for some
		403	external event in conjunction with something not expressible using other
		404	libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is
		405	usually a better approach for this kind of thing.
225		406
226	This flags value could be used to implement alternative looping	407	Here are the gory details of what C<ev_loop> does:
227	constructs, but the C<prepare> and C<check> watchers provide a better and	408
228	more generic mechanism.	409	* If there are no active watchers (reference count is zero), return.
		410	- Queue prepare watchers and then call all outstanding watchers.
		411	- If we have been forked, recreate the kernel state.
		412	- Update the kernel state with all outstanding changes.
		413	- Update the "event loop time".
		414	- Calculate for how long to block.
		415	- Block the process, waiting for any events.
		416	- Queue all outstanding I/O (fd) events.
		417	- Update the "event loop time" and do time jump handling.
		418	- Queue all outstanding timers.
		419	- Queue all outstanding periodics.
		420	- If no events are pending now, queue all idle watchers.
		421	- Queue all check watchers.
		422	- Call all queued watchers in reverse order (i.e. check watchers first).
		423	Signals and child watchers are implemented as I/O watchers, and will
		424	be handled here by queueing them when their watcher gets executed.
		425	- If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
		426	were used, return, otherwise continue with step *.
		427
		428	Example: queue some jobs and then loop until no events are outsanding
		429	anymore.
		430
		431	... queue jobs here, make sure they register event watchers as long
		432	... as they still have work to do (even an idle watcher will do..)
		433	ev_loop (my_loop, 0);
		434	... jobs done. yeah!
229		435
230	=item ev_unloop (loop, how)	436	=item ev_unloop (loop, how)
231		437
232	Can be used to make a call to C<ev_loop> return early. The C<how> argument	438	Can be used to make a call to C<ev_loop> return early (but only after it
		439	has processed all outstanding events). The C<how> argument must be either
233	must be either C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop>	440	C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or
234	call return, or C<EVUNLOOP_ALL>, which will make all nested C<ev_loop>	441	C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.
235	calls return.
236		442
237	=item ev_ref (loop)	443	=item ev_ref (loop)
238		444
239	=item ev_unref (loop)	445	=item ev_unref (loop)
240		446
241	Ref/unref can be used to add or remove a refcount on the event loop: Every	447	Ref/unref can be used to add or remove a reference count on the event
242	watcher keeps one reference. If you have a long-runing watcher you never	448	loop: Every watcher keeps one reference, and as long as the reference
243	unregister that should not keep ev_loop from running, ev_unref() after	449	count is nonzero, C<ev_loop> will not return on its own. If you have
244	starting, and ev_ref() before stopping it. Libev itself uses this for	450	a watcher you never unregister that should not keep C<ev_loop> from
245	example for its internal signal pipe: It is not visible to you as a user	451	returning, ev_unref() after starting, and ev_ref() before stopping it. For
246	and should not keep C<ev_loop> from exiting if the work is done. It is	452	example, libev itself uses this for its internal signal pipe: It is not
247	also an excellent way to do this for generic recurring timers or from	453	visible to the libev user and should not keep C<ev_loop> from exiting if
248	within third-party libraries. Just remember to unref after start and ref	454	no event watchers registered by it are active. It is also an excellent
249	before stop.	455	way to do this for generic recurring timers or from within third-party
		456	libraries. Just remember to I<unref after start> and I<ref before stop>.
		457
		458	Example: create a signal watcher, but keep it from keeping C<ev_loop>
		459	running when nothing else is active.
		460
		461	struct dv_signal exitsig;
		462	ev_signal_init (&exitsig, sig_cb, SIGINT);
		463	ev_signal_start (myloop, &exitsig);
		464	evf_unref (myloop);
		465
		466	Example: for some weird reason, unregister the above signal handler again.
		467
		468	ev_ref (myloop);
		469	ev_signal_stop (myloop, &exitsig);
250		470
251	=back	471	=back
252		472
253	=head1 ANATOMY OF A WATCHER	473	=head1 ANATOMY OF A WATCHER
254		474
255	A watcher is a structure that you create and register to record your	475	A watcher is a structure that you create and register to record your
256	interest in some event. For instance, if you want to wait for STDIN to	476	interest in some event. For instance, if you want to wait for STDIN to
257	become readable, you would create an ev_io watcher for that:	477	become readable, you would create an C<ev_io> watcher for that:
258		478
259	static void my_cb (struct ev_loop loop, struct ev_io w, int revents)	479	static void my_cb (struct ev_loop loop, struct ev_io w, int revents)
260	{	480	{
261	ev_io_stop (w);	481	ev_io_stop (w);
262	ev_unloop (loop, EVUNLOOP_ALL);	482	ev_unloop (loop, EVUNLOOP_ALL);
…		…
289	*) >>), and you can stop watching for events at any time by calling the	509	*) >>), and you can stop watching for events at any time by calling the
290	corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>.	510	corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>.
291		511
292	As long as your watcher is active (has been started but not stopped) you	512	As long as your watcher is active (has been started but not stopped) you
293	must not touch the values stored in it. Most specifically you must never	513	must not touch the values stored in it. Most specifically you must never
294	reinitialise it or call its set method.	514	reinitialise it or call its C<set> macro.
295
296	You cna check wether an event is active by calling the C<ev_is_active
297	(watcher *)> macro. To see wether an event is outstanding (but the
298	callback for it has not been called yet) you cna use the C<ev_is_pending
299	(watcher *)> macro.
300		515
301	Each and every callback receives the event loop pointer as first, the	516	Each and every callback receives the event loop pointer as first, the
302	registered watcher structure as second, and a bitset of received events as	517	registered watcher structure as second, and a bitset of received events as
303	third argument.	518	third argument.
304		519
305	The rceeived events usually include a single bit per event type received	520	The received events usually include a single bit per event type received
306	(you can receive multiple events at the same time). The possible bit masks	521	(you can receive multiple events at the same time). The possible bit masks
307	are:	522	are:
308		523
309	=over 4	524	=over 4
310		525
311	=item EV_READ	526	=item C<EV_READ>
312		527
313	=item EV_WRITE	528	=item C<EV_WRITE>
314		529
315	The file descriptor in the ev_io watcher has become readable and/or	530	The file descriptor in the C<ev_io> watcher has become readable and/or
316	writable.	531	writable.
317		532
318	=item EV_TIMEOUT	533	=item C<EV_TIMEOUT>
319		534
320	The ev_timer watcher has timed out.	535	The C<ev_timer> watcher has timed out.
321		536
322	=item EV_PERIODIC	537	=item C<EV_PERIODIC>
323		538
324	The ev_periodic watcher has timed out.	539	The C<ev_periodic> watcher has timed out.
325		540
326	=item EV_SIGNAL	541	=item C<EV_SIGNAL>
327		542
328	The signal specified in the ev_signal watcher has been received by a thread.	543	The signal specified in the C<ev_signal> watcher has been received by a thread.
329		544
330	=item EV_CHILD	545	=item C<EV_CHILD>
331		546
332	The pid specified in the ev_child watcher has received a status change.	547	The pid specified in the C<ev_child> watcher has received a status change.
333		548
334	=item EV_IDLE	549	=item C<EV_IDLE>
335		550
336	The ev_idle watcher has determined that you have nothing better to do.	551	The C<ev_idle> watcher has determined that you have nothing better to do.
337		552
338	=item EV_PREPARE	553	=item C<EV_PREPARE>
339		554
340	=item EV_CHECK	555	=item C<EV_CHECK>
341		556
342	All ev_prepare watchers are invoked just I<before> C<ev_loop> starts	557	All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts
343	to gather new events, and all ev_check watchers are invoked just after	558	to gather new events, and all C<ev_check> watchers are invoked just after
344	C<ev_loop> has gathered them, but before it invokes any callbacks for any	559	C<ev_loop> has gathered them, but before it invokes any callbacks for any
345	received events. Callbacks of both watcher types can start and stop as	560	received events. Callbacks of both watcher types can start and stop as
346	many watchers as they want, and all of them will be taken into account	561	many watchers as they want, and all of them will be taken into account
347	(for example, a ev_prepare watcher might start an idle watcher to keep	562	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
348	C<ev_loop> from blocking).	563	C<ev_loop> from blocking).
349		564
350	=item EV_ERROR	565	=item C<EV_ERROR>
351		566
352	An unspecified error has occured, the watcher has been stopped. This might	567	An unspecified error has occured, the watcher has been stopped. This might
353	happen because the watcher could not be properly started because libev	568	happen because the watcher could not be properly started because libev
354	ran out of memory, a file descriptor was found to be closed or any other	569	ran out of memory, a file descriptor was found to be closed or any other
355	problem. You best act on it by reporting the problem and somehow coping	570	problem. You best act on it by reporting the problem and somehow coping
…		…
361	with the error from read() or write(). This will not work in multithreaded	576	with the error from read() or write(). This will not work in multithreaded
362	programs, though, so beware.	577	programs, though, so beware.
363		578
364	=back	579	=back
365		580
		581	=head2 SUMMARY OF GENERIC WATCHER FUNCTIONS
		582
		583	In the following description, C<TYPE> stands for the watcher type,
		584	e.g. C<timer> for C<ev_timer> watchers and C<io> for C<ev_io> watchers.
		585
		586	=over 4
		587
		588	=item C<ev_init> (ev_TYPE *watcher, callback)
		589
		590	This macro initialises the generic portion of a watcher. The contents
		591	of the watcher object can be arbitrary (so C<malloc> will do). Only
		592	the generic parts of the watcher are initialised, you I<need> to call
		593	the type-specific C<ev_TYPE_set> macro afterwards to initialise the
		594	type-specific parts. For each type there is also a C<ev_TYPE_init> macro
		595	which rolls both calls into one.
		596
		597	You can reinitialise a watcher at any time as long as it has been stopped
		598	(or never started) and there are no pending events outstanding.
		599
		600	The callbakc is always of type C<void ()(ev_loop loop, ev_TYPE *watcher,
		601	int revents)>.
		602
		603	=item C<ev_TYPE_set> (ev_TYPE *, [args])
		604
		605	This macro initialises the type-specific parts of a watcher. You need to
		606	call C<ev_init> at least once before you call this macro, but you can
		607	call C<ev_TYPE_set> any number of times. You must not, however, call this
		608	macro on a watcher that is active (it can be pending, however, which is a
		609	difference to the C<ev_init> macro).
		610
		611	Although some watcher types do not have type-specific arguments
		612	(e.g. C<ev_prepare>) you still need to call its C<set> macro.
		613
		614	=item C<ev_TYPE_init> (ev_TYPE *watcher, callback, [args])
		615
		616	This convinience macro rolls both C<ev_init> and C<ev_TYPE_set> macro
		617	calls into a single call. This is the most convinient method to initialise
		618	a watcher. The same limitations apply, of course.
		619
		620	=item C<ev_TYPE_start> (loop , ev_TYPE watcher)
		621
		622	Starts (activates) the given watcher. Only active watchers will receive
		623	events. If the watcher is already active nothing will happen.
		624
		625	=item C<ev_TYPE_stop> (loop , ev_TYPE watcher)
		626
		627	Stops the given watcher again (if active) and clears the pending
		628	status. It is possible that stopped watchers are pending (for example,
		629	non-repeating timers are being stopped when they become pending), but
		630	C<ev_TYPE_stop> ensures that the watcher is neither active nor pending. If
		631	you want to free or reuse the memory used by the watcher it is therefore a
		632	good idea to always call its C<ev_TYPE_stop> function.
		633
		634	=item bool ev_is_active (ev_TYPE *watcher)
		635
		636	Returns a true value iff the watcher is active (i.e. it has been started
		637	and not yet been stopped). As long as a watcher is active you must not modify
		638	it.
		639
		640	=item bool ev_is_pending (ev_TYPE *watcher)
		641
		642	Returns a true value iff the watcher is pending, (i.e. it has outstanding
		643	events but its callback has not yet been invoked). As long as a watcher
		644	is pending (but not active) you must not call an init function on it (but
		645	C<ev_TYPE_set> is safe) and you must make sure the watcher is available to
		646	libev (e.g. you cnanot C<free ()> it).
		647
		648	=item callback = ev_cb (ev_TYPE *watcher)
		649
		650	Returns the callback currently set on the watcher.
		651
		652	=item ev_cb_set (ev_TYPE *watcher, callback)
		653
		654	Change the callback. You can change the callback at virtually any time
		655	(modulo threads).
		656
		657	=back
		658
		659
366	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	660	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
367		661
368	Each watcher has, by default, a member C<void *data> that you can change	662	Each watcher has, by default, a member C<void *data> that you can change
369	and read at any time, libev will completely ignore it. This cna be used	663	and read at any time, libev will completely ignore it. This can be used
370	to associate arbitrary data with your watcher. If you need more data and	664	to associate arbitrary data with your watcher. If you need more data and
371	don't want to allocate memory and store a pointer to it in that data	665	don't want to allocate memory and store a pointer to it in that data
372	member, you can also "subclass" the watcher type and provide your own	666	member, you can also "subclass" the watcher type and provide your own
373	data:	667	data:
374		668
…		…
396	=head1 WATCHER TYPES	690	=head1 WATCHER TYPES
397		691
398	This section describes each watcher in detail, but will not repeat	692	This section describes each watcher in detail, but will not repeat
399	information given in the last section.	693	information given in the last section.
400		694
		695
401	=head2 struct ev_io - is my file descriptor readable or writable	696	=head2 C<ev_io> - is this file descriptor readable or writable
402		697
403	I/O watchers check wether a file descriptor is readable or writable	698	I/O watchers check whether a file descriptor is readable or writable
404	in each iteration of the event loop (This behaviour is called	699	in each iteration of the event loop (This behaviour is called
405	level-triggering because you keep receiving events as long as the	700	level-triggering because you keep receiving events as long as the
406	condition persists. Remember you cna stop the watcher if you don't want to	701	condition persists. Remember you can stop the watcher if you don't want to
407	act on the event and neither want to receive future events).	702	act on the event and neither want to receive future events).
408		703
		704	In general you can register as many read and/or write event watchers per
		705	fd as you want (as long as you don't confuse yourself). Setting all file
		706	descriptors to non-blocking mode is also usually a good idea (but not
		707	required if you know what you are doing).
		708
		709	You have to be careful with dup'ed file descriptors, though. Some backends
		710	(the linux epoll backend is a notable example) cannot handle dup'ed file
		711	descriptors correctly if you register interest in two or more fds pointing
		712	to the same underlying file/socket etc. description (that is, they share
		713	the same underlying "file open").
		714
		715	If you must do this, then force the use of a known-to-be-good backend
		716	(at the time of this writing, this includes only C<EVBACKEND_SELECT> and
		717	C<EVBACKEND_POLL>).
		718
409	=over 4	719	=over 4
410		720
411	=item ev_io_init (ev_io *, callback, int fd, int events)	721	=item ev_io_init (ev_io *, callback, int fd, int events)
412		722
413	=item ev_io_set (ev_io *, int fd, int events)	723	=item ev_io_set (ev_io *, int fd, int events)
414		724
415	Configures an ev_io watcher. The fd is the file descriptor to rceeive	725	Configures an C<ev_io> watcher. The fd is the file descriptor to rceeive
416	events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ \|	726	events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ \|
417	EV_WRITE> to receive the given events.	727	EV_WRITE> to receive the given events.
418		728
419	=back	729	Please note that most of the more scalable backend mechanisms (for example
		730	epoll and solaris ports) can result in spurious readyness notifications
		731	for file descriptors, so you practically need to use non-blocking I/O (and
		732	treat callback invocation as hint only), or retest separately with a safe
		733	interface before doing I/O (XLib can do this), or force the use of either
		734	C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>, which don't suffer from this
		735	problem. Also note that it is quite easy to have your callback invoked
		736	when the readyness condition is no longer valid even when employing
		737	typical ways of handling events, so its a good idea to use non-blocking
		738	I/O unconditionally.
420		739
		740	=back
		741
		742	Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well
		743	readable, but only once. Since it is likely line-buffered, you could
		744	attempt to read a whole line in the callback:
		745
		746	static void
		747	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
		748	{
		749	ev_io_stop (loop, w);
		750	.. read from stdin here (or from w->fd) and haqndle any I/O errors
		751	}
		752
		753	...
		754	struct ev_loop *loop = ev_default_init (0);
		755	struct ev_io stdin_readable;
		756	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
		757	ev_io_start (loop, &stdin_readable);
		758	ev_loop (loop, 0);
		759
		760
421	=head2 struct ev_timer - relative and optionally recurring timeouts	761	=head2 C<ev_timer> - relative and optionally recurring timeouts
422		762
423	Timer watchers are simple relative timers that generate an event after a	763	Timer watchers are simple relative timers that generate an event after a
424	given time, and optionally repeating in regular intervals after that.	764	given time, and optionally repeating in regular intervals after that.
425		765
426	The timers are based on real time, that is, if you register an event that	766	The timers are based on real time, that is, if you register an event that
427	times out after an hour and youreset your system clock to last years	767	times out after an hour and you reset your system clock to last years
428	time, it will still time out after (roughly) and hour. "Roughly" because	768	time, it will still time out after (roughly) and hour. "Roughly" because
429	detecting time jumps is hard, and soem inaccuracies are unavoidable (the	769	detecting time jumps is hard, and some inaccuracies are unavoidable (the
430	monotonic clock option helps a lot here).	770	monotonic clock option helps a lot here).
		771
		772	The relative timeouts are calculated relative to the C<ev_now ()>
		773	time. This is usually the right thing as this timestamp refers to the time
		774	of the event triggering whatever timeout you are modifying/starting. If
		775	you suspect event processing to be delayed and you I<need> to base the timeout
		776	on the current time, use something like this to adjust for this:
		777
		778	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
		779
		780	The callback is guarenteed to be invoked only when its timeout has passed,
		781	but if multiple timers become ready during the same loop iteration then
		782	order of execution is undefined.
431		783
432	=over 4	784	=over 4
433		785
434	=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)	786	=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)
435		787
…		…
441	later, again, and again, until stopped manually.	793	later, again, and again, until stopped manually.
442		794
443	The timer itself will do a best-effort at avoiding drift, that is, if you	795	The timer itself will do a best-effort at avoiding drift, that is, if you
444	configure a timer to trigger every 10 seconds, then it will trigger at	796	configure a timer to trigger every 10 seconds, then it will trigger at
445	exactly 10 second intervals. If, however, your program cannot keep up with	797	exactly 10 second intervals. If, however, your program cannot keep up with
446	the timer (ecause it takes longer than those 10 seconds to do stuff) the	798	the timer (because it takes longer than those 10 seconds to do stuff) the
447	timer will not fire more than once per event loop iteration.	799	timer will not fire more than once per event loop iteration.
448		800
449	=item ev_timer_again (loop)	801	=item ev_timer_again (loop)
450		802
451	This will act as if the timer timed out and restart it again if it is	803	This will act as if the timer timed out and restart it again if it is
…		…
458		810
459	This sounds a bit complicated, but here is a useful and typical	811	This sounds a bit complicated, but here is a useful and typical
460	example: Imagine you have a tcp connection and you want a so-called idle	812	example: Imagine you have a tcp connection and you want a so-called idle
461	timeout, that is, you want to be called when there have been, say, 60	813	timeout, that is, you want to be called when there have been, say, 60
462	seconds of inactivity on the socket. The easiest way to do this is to	814	seconds of inactivity on the socket. The easiest way to do this is to
463	configure an ev_timer with after=repeat=60 and calling ev_timer_again each	815	configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each
464	time you successfully read or write some data. If you go into an idle	816	time you successfully read or write some data. If you go into an idle
465	state where you do not expect data to travel on the socket, you can stop	817	state where you do not expect data to travel on the socket, you can stop
466	the timer, and again will automatically restart it if need be.	818	the timer, and again will automatically restart it if need be.
467		819
468	=back	820	=back
469		821
470	=head2 ev_periodic	822	Example: create a timer that fires after 60 seconds.
		823
		824	static void
		825	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
		826	{
		827	.. one minute over, w is actually stopped right here
		828	}
		829
		830	struct ev_timer mytimer;
		831	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
		832	ev_timer_start (loop, &mytimer);
		833
		834	Example: create a timeout timer that times out after 10 seconds of
		835	inactivity.
		836
		837	static void
		838	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
		839	{
		840	.. ten seconds without any activity
		841	}
		842
		843	struct ev_timer mytimer;
		844	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
		845	ev_timer_again (&mytimer); /* start timer */
		846	ev_loop (loop, 0);
		847
		848	// and in some piece of code that gets executed on any "activity":
		849	// reset the timeout to start ticking again at 10 seconds
		850	ev_timer_again (&mytimer);
		851
		852
		853	=head2 C<ev_periodic> - to cron or not to cron
471		854
472	Periodic watchers are also timers of a kind, but they are very versatile	855	Periodic watchers are also timers of a kind, but they are very versatile
473	(and unfortunately a bit complex).	856	(and unfortunately a bit complex).
474		857
475	Unlike ev_timer's, they are not based on real time (or relative time)	858	Unlike C<ev_timer>'s, they are not based on real time (or relative time)
476	but on wallclock time (absolute time). You can tell a periodic watcher	859	but on wallclock time (absolute time). You can tell a periodic watcher
477	to trigger "at" some specific point in time. For example, if you tell a	860	to trigger "at" some specific point in time. For example, if you tell a
478	periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now ()	861	periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now ()
479	+ 10.>) and then reset your system clock to the last year, then it will	862	+ 10.>) and then reset your system clock to the last year, then it will
480	take a year to trigger the event (unlike an ev_timer, which would trigger	863	take a year to trigger the event (unlike an C<ev_timer>, which would trigger
481	roughly 10 seconds later and of course not if you reset your system time	864	roughly 10 seconds later and of course not if you reset your system time
482	again).	865	again).
483		866
484	They can also be used to implement vastly more complex timers, such as	867	They can also be used to implement vastly more complex timers, such as
485	triggering an event on eahc midnight, local time.	868	triggering an event on eahc midnight, local time.
486		869
		870	As with timers, the callback is guarenteed to be invoked only when the
		871	time (C<at>) has been passed, but if multiple periodic timers become ready
		872	during the same loop iteration then order of execution is undefined.
		873
487	=over 4	874	=over 4
488		875
489	=item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)	876	=item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)
490		877
491	=item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)	878	=item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)
492		879
493	Lots of arguments, lets sort it out... There are basically three modes of	880	Lots of arguments, lets sort it out... There are basically three modes of
494	operation, and we will explain them from simplest to complex:	881	operation, and we will explain them from simplest to complex:
495
496		882
497	=over 4	883	=over 4
498		884
499	=item * absolute timer (interval = reschedule_cb = 0)	885	=item * absolute timer (interval = reschedule_cb = 0)
500		886
…		…
514		900
515	ev_periodic_set (&periodic, 0., 3600., 0);	901	ev_periodic_set (&periodic, 0., 3600., 0);
516		902
517	This doesn't mean there will always be 3600 seconds in between triggers,	903	This doesn't mean there will always be 3600 seconds in between triggers,
518	but only that the the callback will be called when the system time shows a	904	but only that the the callback will be called when the system time shows a
519	full hour (UTC), or more correct, when the system time is evenly divisible	905	full hour (UTC), or more correctly, when the system time is evenly divisible
520	by 3600.	906	by 3600.
521		907
522	Another way to think about it (for the mathematically inclined) is that	908	Another way to think about it (for the mathematically inclined) is that
523	ev_periodic will try to run the callback in this mode at the next possible	909	C<ev_periodic> will try to run the callback in this mode at the next possible
524	time where C<time = at (mod interval)>, regardless of any time jumps.	910	time where C<time = at (mod interval)>, regardless of any time jumps.
525		911
526	=item * manual reschedule mode (reschedule_cb = callback)	912	=item * manual reschedule mode (reschedule_cb = callback)
527		913
528	In this mode the values for C<interval> and C<at> are both being	914	In this mode the values for C<interval> and C<at> are both being
529	ignored. Instead, each time the periodic watcher gets scheduled, the	915	ignored. Instead, each time the periodic watcher gets scheduled, the
530	reschedule callback will be called with the watcher as first, and the	916	reschedule callback will be called with the watcher as first, and the
531	current time as second argument.	917	current time as second argument.
532		918
533	NOTE: I<This callback MUST NOT stop or destroy the periodic or any other	919	NOTE: I<This callback MUST NOT stop or destroy any periodic watcher,
534	periodic watcher, ever, or make any event loop modificstions>. If you need	920	ever, or make any event loop modifications>. If you need to stop it,
535	to stop it, return 1e30 (or so, fudge fudge) and stop it afterwards.	921	return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by
		922	starting a prepare watcher).
536		923
537	Its prototype is c<ev_tstamp (reschedule_cb)(struct ev_periodic w,	924	Its prototype is C<ev_tstamp (reschedule_cb)(struct ev_periodic w,
538	ev_tstamp now)>, e.g.:	925	ev_tstamp now)>, e.g.:
539		926
540	static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)	927	static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)
541	{	928	{
542	return now + 60.;	929	return now + 60.;
…		…
545	It must return the next time to trigger, based on the passed time value	932	It must return the next time to trigger, based on the passed time value
546	(that is, the lowest time value larger than to the second argument). It	933	(that is, the lowest time value larger than to the second argument). It
547	will usually be called just before the callback will be triggered, but	934	will usually be called just before the callback will be triggered, but
548	might be called at other times, too.	935	might be called at other times, too.
549		936
		937	NOTE: I<< This callback must always return a time that is later than the
		938	passed C<now> value >>. Not even C<now> itself will do, it I<must> be larger.
		939
550	This can be used to create very complex timers, such as a timer that	940	This can be used to create very complex timers, such as a timer that
551	triggers on each midnight, local time. To do this, you would calculate the	941	triggers on each midnight, local time. To do this, you would calculate the
552	next midnight after C<now> and return the timestamp value for this. How you do this	942	next midnight after C<now> and return the timestamp value for this. How
553	is, again, up to you (but it is not trivial).	943	you do this is, again, up to you (but it is not trivial, which is the main
		944	reason I omitted it as an example).
554		945
555	=back	946	=back
556		947
557	=item ev_periodic_again (loop, ev_periodic *)	948	=item ev_periodic_again (loop, ev_periodic *)
558		949
…		…
561	a different time than the last time it was called (e.g. in a crond like	952	a different time than the last time it was called (e.g. in a crond like
562	program when the crontabs have changed).	953	program when the crontabs have changed).
563		954
564	=back	955	=back
565		956
		957	Example: call a callback every hour, or, more precisely, whenever the
		958	system clock is divisible by 3600. The callback invocation times have
		959	potentially a lot of jittering, but good long-term stability.
		960
		961	static void
		962	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
		963	{
		964	... its now a full hour (UTC, or TAI or whatever your clock follows)
		965	}
		966
		967	struct ev_periodic hourly_tick;
		968	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
		969	ev_periodic_start (loop, &hourly_tick);
		970
		971	Example: the same as above, but use a reschedule callback to do it:
		972
		973	#include <math.h>
		974
		975	static ev_tstamp
		976	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
		977	{
		978	return fmod (now, 3600.) + 3600.;
		979	}
		980
		981	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
		982
		983	Example: call a callback every hour, starting now:
		984
		985	struct ev_periodic hourly_tick;
		986	ev_periodic_init (&hourly_tick, clock_cb,
		987	fmod (ev_now (loop), 3600.), 3600., 0);
		988	ev_periodic_start (loop, &hourly_tick);
		989
		990
566	=head2 ev_signal - signal me when a signal gets signalled	991	=head2 C<ev_signal> - signal me when a signal gets signalled
567		992
568	Signal watchers will trigger an event when the process receives a specific	993	Signal watchers will trigger an event when the process receives a specific
569	signal one or more times. Even though signals are very asynchronous, libev	994	signal one or more times. Even though signals are very asynchronous, libev
570	will try its best to deliver signals synchronously, i.e. as part of the	995	will try it's best to deliver signals synchronously, i.e. as part of the
571	normal event processing, like any other event.	996	normal event processing, like any other event.
572		997
573	You cna configure as many watchers as you like per signal. Only when the	998	You can configure as many watchers as you like per signal. Only when the
574	first watcher gets started will libev actually register a signal watcher	999	first watcher gets started will libev actually register a signal watcher
575	with the kernel (thus it coexists with your own signal handlers as long	1000	with the kernel (thus it coexists with your own signal handlers as long
576	as you don't register any with libev). Similarly, when the last signal	1001	as you don't register any with libev). Similarly, when the last signal
577	watcher for a signal is stopped libev will reset the signal handler to	1002	watcher for a signal is stopped libev will reset the signal handler to
578	SIG_DFL (regardless of what it was set to before).	1003	SIG_DFL (regardless of what it was set to before).
…		…
586	Configures the watcher to trigger on the given signal number (usually one	1011	Configures the watcher to trigger on the given signal number (usually one
587	of the C<SIGxxx> constants).	1012	of the C<SIGxxx> constants).
588		1013
589	=back	1014	=back
590		1015
		1016
591	=head2 ev_child - wait for pid status changes	1017	=head2 C<ev_child> - wait for pid status changes
592		1018
593	Child watchers trigger when your process receives a SIGCHLD in response to	1019	Child watchers trigger when your process receives a SIGCHLD in response to
594	some child status changes (most typically when a child of yours dies).	1020	some child status changes (most typically when a child of yours dies).
595		1021
596	=over 4	1022	=over 4
…		…
600	=item ev_child_set (ev_child *, int pid)	1026	=item ev_child_set (ev_child *, int pid)
601		1027
602	Configures the watcher to wait for status changes of process C<pid> (or	1028	Configures the watcher to wait for status changes of process C<pid> (or
603	I<any> process if C<pid> is specified as C<0>). The callback can look	1029	I<any> process if C<pid> is specified as C<0>). The callback can look
604	at the C<rstatus> member of the C<ev_child> watcher structure to see	1030	at the C<rstatus> member of the C<ev_child> watcher structure to see
605	the status word (use the macros from C<sys/wait.h>). The C<rpid> member	1031	the status word (use the macros from C<sys/wait.h> and see your systems
606	contains the pid of the process causing the status change.	1032	C<waitpid> documentation). The C<rpid> member contains the pid of the
		1033	process causing the status change.
607		1034
608	=back	1035	=back
609		1036
		1037	Example: try to exit cleanly on SIGINT and SIGTERM.
		1038
		1039	static void
		1040	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
		1041	{
		1042	ev_unloop (loop, EVUNLOOP_ALL);
		1043	}
		1044
		1045	struct ev_signal signal_watcher;
		1046	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
		1047	ev_signal_start (loop, &sigint_cb);
		1048
		1049
610	=head2 ev_idle - when you've got nothing better to do	1050	=head2 C<ev_idle> - when you've got nothing better to do
611		1051
612	Idle watchers trigger events when there are no other I/O or timer (or	1052	Idle watchers trigger events when there are no other events are pending
613	periodic) events pending. That is, as long as your process is busy	1053	(prepare, check and other idle watchers do not count). That is, as long
614	handling sockets or timeouts it will not be called. But when your process	1054	as your process is busy handling sockets or timeouts (or even signals,
615	is idle all idle watchers are being called again and again - until	1055	imagine) it will not be triggered. But when your process is idle all idle
		1056	watchers are being called again and again, once per event loop iteration -
616	stopped, that is, or your process receives more events.	1057	until stopped, that is, or your process receives more events and becomes
		1058	busy.
617		1059
618	The most noteworthy effect is that as long as any idle watchers are	1060	The most noteworthy effect is that as long as any idle watchers are
619	active, the process will not block when waiting for new events.	1061	active, the process will not block when waiting for new events.
620		1062
621	Apart from keeping your process non-blocking (which is a useful	1063	Apart from keeping your process non-blocking (which is a useful
…		…
631	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,	1073	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
632	believe me.	1074	believe me.
633		1075
634	=back	1076	=back
635		1077
636	=head2 prepare and check - your hooks into the event loop	1078	Example: dynamically allocate an C<ev_idle>, start it, and in the
		1079	callback, free it. Alos, use no error checking, as usual.
637		1080
		1081	static void
		1082	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
		1083	{
		1084	free (w);
		1085	// now do something you wanted to do when the program has
		1086	// no longer asnything immediate to do.
		1087	}
		1088
		1089	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
		1090	ev_idle_init (idle_watcher, idle_cb);
		1091	ev_idle_start (loop, idle_cb);
		1092
		1093
		1094	=head2 C<ev_prepare> and C<ev_check> - customise your event loop
		1095
638	Prepare and check watchers usually (but not always) are used in	1096	Prepare and check watchers are usually (but not always) used in tandem:
639	tandom. Prepare watchers get invoked before the process blocks and check	1097	prepare watchers get invoked before the process blocks and check watchers
640	watchers afterwards.	1098	afterwards.
641		1099
642	Their main purpose is to integrate other event mechanisms into libev. This	1100	Their main purpose is to integrate other event mechanisms into libev and
643	could be used, for example, to track variable changes, implement your own	1101	their use is somewhat advanced. This could be used, for example, to track
644	watchers, integrate net-snmp or a coroutine library and lots more.	1102	variable changes, implement your own watchers, integrate net-snmp or a
		1103	coroutine library and lots more.
645		1104
646	This is done by examining in each prepare call which file descriptors need	1105	This is done by examining in each prepare call which file descriptors need
647	to be watched by the other library, registering ev_io watchers for them	1106	to be watched by the other library, registering C<ev_io> watchers for
648	and starting an ev_timer watcher for any timeouts (many libraries provide	1107	them and starting an C<ev_timer> watcher for any timeouts (many libraries
649	just this functionality). Then, in the check watcher you check for any	1108	provide just this functionality). Then, in the check watcher you check for
650	events that occured (by making your callbacks set soem flags for example)	1109	any events that occured (by checking the pending status of all watchers
651	and call back into the library.	1110	and stopping them) and call back into the library. The I/O and timer
		1111	callbacks will never actually be called (but must be valid nevertheless,
		1112	because you never know, you know?).
652		1113
653	As another example, the perl Coro module uses these hooks to integrate	1114	As another example, the Perl Coro module uses these hooks to integrate
654	coroutines into libev programs, by yielding to other active coroutines	1115	coroutines into libev programs, by yielding to other active coroutines
655	during each prepare and only letting the process block if no coroutines	1116	during each prepare and only letting the process block if no coroutines
656	are ready to run.	1117	are ready to run (it's actually more complicated: it only runs coroutines
		1118	with priority higher than or equal to the event loop and one coroutine
		1119	of lower priority, but only once, using idle watchers to keep the event
		1120	loop from blocking if lower-priority coroutines are active, thus mapping
		1121	low-priority coroutines to idle/background tasks).
657		1122
658	=over 4	1123	=over 4
659		1124
660	=item ev_prepare_init (ev_prepare *, callback)	1125	=item ev_prepare_init (ev_prepare *, callback)
661		1126
662	=item ev_check_init (ev_check *, callback)	1127	=item ev_check_init (ev_check *, callback)
663		1128
664	Initialises and configures the prepare or check watcher - they have no	1129	Initialises and configures the prepare or check watcher - they have no
665	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>	1130	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>
666	macros, but using them is utterly, utterly pointless.	1131	macros, but using them is utterly, utterly and completely pointless.
667		1132
668	=back	1133	=back
		1134
		1135	Example: TODO.
		1136
		1137
		1138	=head2 C<ev_embed> - when one backend isn't enough
		1139
		1140	This is a rather advanced watcher type that lets you embed one event loop
		1141	into another (currently only C<ev_io> events are supported in the embedded
		1142	loop, other types of watchers might be handled in a delayed or incorrect
		1143	fashion and must not be used).
		1144
		1145	There are primarily two reasons you would want that: work around bugs and
		1146	prioritise I/O.
		1147
		1148	As an example for a bug workaround, the kqueue backend might only support
		1149	sockets on some platform, so it is unusable as generic backend, but you
		1150	still want to make use of it because you have many sockets and it scales
		1151	so nicely. In this case, you would create a kqueue-based loop and embed it
		1152	into your default loop (which might use e.g. poll). Overall operation will
		1153	be a bit slower because first libev has to poll and then call kevent, but
		1154	at least you can use both at what they are best.
		1155
		1156	As for prioritising I/O: rarely you have the case where some fds have
		1157	to be watched and handled very quickly (with low latency), and even
		1158	priorities and idle watchers might have too much overhead. In this case
		1159	you would put all the high priority stuff in one loop and all the rest in
		1160	a second one, and embed the second one in the first.
		1161
		1162	As long as the watcher is active, the callback will be invoked every time
		1163	there might be events pending in the embedded loop. The callback must then
		1164	call C<ev_embed_sweep (mainloop, watcher)> to make a single sweep and invoke
		1165	their callbacks (you could also start an idle watcher to give the embedded
		1166	loop strictly lower priority for example). You can also set the callback
		1167	to C<0>, in which case the embed watcher will automatically execute the
		1168	embedded loop sweep.
		1169
		1170	As long as the watcher is started it will automatically handle events. The
		1171	callback will be invoked whenever some events have been handled. You can
		1172	set the callback to C<0> to avoid having to specify one if you are not
		1173	interested in that.
		1174
		1175	Also, there have not currently been made special provisions for forking:
		1176	when you fork, you not only have to call C<ev_loop_fork> on both loops,
		1177	but you will also have to stop and restart any C<ev_embed> watchers
		1178	yourself.
		1179
		1180	Unfortunately, not all backends are embeddable, only the ones returned by
		1181	C<ev_embeddable_backends> are, which, unfortunately, does not include any
		1182	portable one.
		1183
		1184	So when you want to use this feature you will always have to be prepared
		1185	that you cannot get an embeddable loop. The recommended way to get around
		1186	this is to have a separate variables for your embeddable loop, try to
		1187	create it, and if that fails, use the normal loop for everything:
		1188
		1189	struct ev_loop *loop_hi = ev_default_init (0);
		1190	struct ev_loop *loop_lo = 0;
		1191	struct ev_embed embed;
		1192
		1193	// see if there is a chance of getting one that works
		1194	// (remember that a flags value of 0 means autodetection)
		1195	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
		1196	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
		1197	: 0;
		1198
		1199	// if we got one, then embed it, otherwise default to loop_hi
		1200	if (loop_lo)
		1201	{
		1202	ev_embed_init (&embed, 0, loop_lo);
		1203	ev_embed_start (loop_hi, &embed);
		1204	}
		1205	else
		1206	loop_lo = loop_hi;
		1207
		1208	=over 4
		1209
		1210	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)
		1211
		1212	=item ev_embed_set (ev_embed , callback, struct ev_loop embedded_loop)
		1213
		1214	Configures the watcher to embed the given loop, which must be
		1215	embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be
		1216	invoked automatically, otherwise it is the responsibility of the callback
		1217	to invoke it (it will continue to be called until the sweep has been done,
		1218	if you do not want thta, you need to temporarily stop the embed watcher).
		1219
		1220	=item ev_embed_sweep (loop, ev_embed *)
		1221
		1222	Make a single, non-blocking sweep over the embedded loop. This works
		1223	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
		1224	apropriate way for embedded loops.
		1225
		1226	=back
		1227
669		1228
670	=head1 OTHER FUNCTIONS	1229	=head1 OTHER FUNCTIONS
671		1230
672	There are some other fucntions of possible interest. Described. Here. Now.	1231	There are some other functions of possible interest. Described. Here. Now.
673		1232
674	=over 4	1233	=over 4
675		1234
676	=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)	1235	=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)
677		1236
678	This function combines a simple timer and an I/O watcher, calls your	1237	This function combines a simple timer and an I/O watcher, calls your
679	callback on whichever event happens first and automatically stop both	1238	callback on whichever event happens first and automatically stop both
680	watchers. This is useful if you want to wait for a single event on an fd	1239	watchers. This is useful if you want to wait for a single event on an fd
681	or timeout without havign to allocate/configure/start/stop/free one or	1240	or timeout without having to allocate/configure/start/stop/free one or
682	more watchers yourself.	1241	more watchers yourself.
683		1242
684	If C<fd> is less than 0, then no I/O watcher will be started and events is	1243	If C<fd> is less than 0, then no I/O watcher will be started and events
685	ignored. Otherwise, an ev_io watcher for the given C<fd> and C<events> set	1244	is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and
686	will be craeted and started.	1245	C<events> set will be craeted and started.
687		1246
688	If C<timeout> is less than 0, then no timeout watcher will be	1247	If C<timeout> is less than 0, then no timeout watcher will be
689	started. Otherwise an ev_timer watcher with after = C<timeout> (and repeat	1248	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
690	= 0) will be started.	1249	repeat = 0) will be started. While C<0> is a valid timeout, it is of
		1250	dubious value.
691		1251
692	The callback has the type C<void (cb)(int revents, void arg)> and	1252	The callback has the type C<void (cb)(int revents, void arg)> and gets
693	gets passed an events set (normally a combination of EV_ERROR, EV_READ,	1253	passed an C<revents> set like normal event callbacks (a combination of
694	EV_WRITE or EV_TIMEOUT) and the C<arg> value passed to C<ev_once>:	1254	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
		1255	value passed to C<ev_once>:
695		1256
696	static void stdin_ready (int revents, void *arg)	1257	static void stdin_ready (int revents, void *arg)
697	{	1258	{
698	if (revents & EV_TIMEOUT)	1259	if (revents & EV_TIMEOUT)
699	/* doh, nothing entered */	1260	/* doh, nothing entered */;
700	else if (revents & EV_READ)	1261	else if (revents & EV_READ)
701	/* stdin might have data for us, joy! */	1262	/* stdin might have data for us, joy! */;
702	}	1263	}
703		1264
704	ev_once (STDIN_FILENO, EV_READm 10., stdin_ready, 0);	1265	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
705		1266
706	=item ev_feed_event (loop, watcher, int events)	1267	=item ev_feed_event (ev_loop , watcher , int revents)
707		1268
708	Feeds the given event set into the event loop, as if the specified event	1269	Feeds the given event set into the event loop, as if the specified event
709	has happened for the specified watcher (which must be a pointer to an	1270	had happened for the specified watcher (which must be a pointer to an
710	initialised but not necessarily active event watcher).	1271	initialised but not necessarily started event watcher).
711		1272
712	=item ev_feed_fd_event (loop, int fd, int revents)	1273	=item ev_feed_fd_event (ev_loop *, int fd, int revents)
713		1274
714	Feed an event on the given fd, as if a file descriptor backend detected it.	1275	Feed an event on the given fd, as if a file descriptor backend detected
		1276	the given events it.
715		1277
716	=item ev_feed_signal_event (loop, int signum)	1278	=item ev_feed_signal_event (ev_loop *loop, int signum)
717		1279
718	Feed an event as if the given signal occured (loop must be the default loop!).	1280	Feed an event as if the given signal occured (C<loop> must be the default
		1281	loop!).
719		1282
720	=back	1283	=back
		1284
		1285
		1286	=head1 LIBEVENT EMULATION
		1287
		1288	Libev offers a compatibility emulation layer for libevent. It cannot
		1289	emulate the internals of libevent, so here are some usage hints:
		1290
		1291	=over 4
		1292
		1293	=item * Use it by including <event.h>, as usual.
		1294
		1295	=item * The following members are fully supported: ev_base, ev_callback,
		1296	ev_arg, ev_fd, ev_res, ev_events.
		1297
		1298	=item * Avoid using ev_flags and the EVLIST_*-macros, while it is
		1299	maintained by libev, it does not work exactly the same way as in libevent (consider
		1300	it a private API).
		1301
		1302	=item * Priorities are not currently supported. Initialising priorities
		1303	will fail and all watchers will have the same priority, even though there
		1304	is an ev_pri field.
		1305
		1306	=item * Other members are not supported.
		1307
		1308	=item * The libev emulation is I<not> ABI compatible to libevent, you need
		1309	to use the libev header file and library.
		1310
		1311	=back
		1312
		1313	=head1 C++ SUPPORT
		1314
		1315	Libev comes with some simplistic wrapper classes for C++ that mainly allow
		1316	you to use some convinience methods to start/stop watchers and also change
		1317	the callback model to a model using method callbacks on objects.
		1318
		1319	To use it,
		1320
		1321	#include <ev++.h>
		1322
		1323	(it is not installed by default). This automatically includes F<ev.h>
		1324	and puts all of its definitions (many of them macros) into the global
		1325	namespace. All C++ specific things are put into the C<ev> namespace.
		1326
		1327	It should support all the same embedding options as F<ev.h>, most notably
		1328	C<EV_MULTIPLICITY>.
		1329
		1330	Here is a list of things available in the C<ev> namespace:
		1331
		1332	=over 4
		1333
		1334	=item C<ev::READ>, C<ev::WRITE> etc.
		1335
		1336	These are just enum values with the same values as the C<EV_READ> etc.
		1337	macros from F<ev.h>.
		1338
		1339	=item C<ev::tstamp>, C<ev::now>
		1340
		1341	Aliases to the same types/functions as with the C<ev_> prefix.
		1342
		1343	=item C<ev::io>, C<ev::timer>, C<ev::periodic>, C<ev::idle>, C<ev::sig> etc.
		1344
		1345	For each C<ev_TYPE> watcher in F<ev.h> there is a corresponding class of
		1346	the same name in the C<ev> namespace, with the exception of C<ev_signal>
		1347	which is called C<ev::sig> to avoid clashes with the C<signal> macro
		1348	defines by many implementations.
		1349
		1350	All of those classes have these methods:
		1351
		1352	=over 4
		1353
		1354	=item ev::TYPE::TYPE (object , object::method )
		1355
		1356	=item ev::TYPE::TYPE (object , object::method , struct ev_loop *)
		1357
		1358	=item ev::TYPE::~TYPE
		1359
		1360	The constructor takes a pointer to an object and a method pointer to
		1361	the event handler callback to call in this class. The constructor calls
		1362	C<ev_init> for you, which means you have to call the C<set> method
		1363	before starting it. If you do not specify a loop then the constructor
		1364	automatically associates the default loop with this watcher.
		1365
		1366	The destructor automatically stops the watcher if it is active.
		1367
		1368	=item w->set (struct ev_loop *)
		1369
		1370	Associates a different C<struct ev_loop> with this watcher. You can only
		1371	do this when the watcher is inactive (and not pending either).
		1372
		1373	=item w->set ([args])
		1374
		1375	Basically the same as C<ev_TYPE_set>, with the same args. Must be
		1376	called at least once. Unlike the C counterpart, an active watcher gets
		1377	automatically stopped and restarted.
		1378
		1379	=item w->start ()
		1380
		1381	Starts the watcher. Note that there is no C<loop> argument as the
		1382	constructor already takes the loop.
		1383
		1384	=item w->stop ()
		1385
		1386	Stops the watcher if it is active. Again, no C<loop> argument.
		1387
		1388	=item w->again () C<ev::timer>, C<ev::periodic> only
		1389
		1390	For C<ev::timer> and C<ev::periodic>, this invokes the corresponding
		1391	C<ev_TYPE_again> function.
		1392
		1393	=item w->sweep () C<ev::embed> only
		1394
		1395	Invokes C<ev_embed_sweep>.
		1396
		1397	=back
		1398
		1399	=back
		1400
		1401	Example: Define a class with an IO and idle watcher, start one of them in
		1402	the constructor.
		1403
		1404	class myclass
		1405	{
		1406	ev_io io; void io_cb (ev::io &w, int revents);
		1407	ev_idle idle void idle_cb (ev::idle &w, int revents);
		1408
		1409	myclass ();
		1410	}
		1411
		1412	myclass::myclass (int fd)
		1413	: io (this, &myclass::io_cb),
		1414	idle (this, &myclass::idle_cb)
		1415	{
		1416	io.start (fd, ev::READ);
		1417	}
721		1418
722	=head1 AUTHOR	1419	=head1 AUTHOR
723		1420
724	Marc Lehmann <libev@schmorp.de>.	1421	Marc Lehmann <libev@schmorp.de>.
725		1422

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Comparing libev/ev.pod (file contents): Revision 1.1 by root, Mon Nov 12 07:58:13 2007 UTC vs. Revision 1.38 by root, Sat Nov 24 09:48:38 2007 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.1 by root, Mon Nov 12 07:58:13 2007 UTC vs.
Revision 1.38 by root, Sat Nov 24 09:48:38 2007 UTC