[ViewVC] Diff of: cvs/libev/ev.3

Comparing libev/ev.3 (file contents):
Revision 1.21 by root, Mon Nov 26 10:20:42 2007 UTC vs.
Revision 1.45 by root, Sat Dec 8 22:11:14 2007 UTC

…		…
127	.\}	127	.\}
128	.rm #[ #] #H #V #F C	128	.rm #[ #] #H #V #F C
129	.\" ========================================================================	129	.\" ========================================================================
130	.\"	130	.\"
131	.IX Title ""<STANDARD INPUT>" 1"	131	.IX Title ""<STANDARD INPUT>" 1"
132	.TH "<STANDARD INPUT>" 1 "2007-11-26" "perl v5.8.8" "User Contributed Perl Documentation"	132	.TH "<STANDARD INPUT>" 1 "2007-12-08" "perl v5.8.8" "User Contributed Perl Documentation"
133	.SH "NAME"	133	.SH "NAME"
134	libev \- a high performance full\-featured event loop written in C	134	libev \- a high performance full\-featured event loop written in C
135	.SH "SYNOPSIS"	135	.SH "SYNOPSIS"
136	.IX Header "SYNOPSIS"	136	.IX Header "SYNOPSIS"
137	.Vb 1	137	.Vb 1
138	\& #include <ev.h>	138	\& #include <ev.h>
139	.Ve	139	.Ve
		140	.SH "EXAMPLE PROGRAM"
		141	.IX Header "EXAMPLE PROGRAM"
		142	.Vb 1
		143	\& #include <ev.h>
		144	.Ve
		145	.PP
		146	.Vb 2
		147	\& ev_io stdin_watcher;
		148	\& ev_timer timeout_watcher;
		149	.Ve
		150	.PP
		151	.Vb 8
		152	\& /* called when data readable on stdin */
		153	\& static void
		154	\& stdin_cb (EV_P_ struct ev_io *w, int revents)
		155	\& {
		156	\& /* puts ("stdin ready"); */
		157	\& ev_io_stop (EV_A_ w); /* just a syntax example */
		158	\& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */
		159	\& }
		160	.Ve
		161	.PP
		162	.Vb 6
		163	\& static void
		164	\& timeout_cb (EV_P_ struct ev_timer *w, int revents)
		165	\& {
		166	\& /* puts ("timeout"); */
		167	\& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */
		168	\& }
		169	.Ve
		170	.PP
		171	.Vb 4
		172	\& int
		173	\& main (void)
		174	\& {
		175	\& struct ev_loop *loop = ev_default_loop (0);
		176	.Ve
		177	.PP
		178	.Vb 3
		179	\& /* initialise an io watcher, then start it */
		180	\& ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
		181	\& ev_io_start (loop, &stdin_watcher);
		182	.Ve
		183	.PP
		184	.Vb 3
		185	\& /* simple non-repeating 5.5 second timeout */
		186	\& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
		187	\& ev_timer_start (loop, &timeout_watcher);
		188	.Ve
		189	.PP
		190	.Vb 2
		191	\& /* loop till timeout or data ready */
		192	\& ev_loop (loop, 0);
		193	.Ve
		194	.PP
		195	.Vb 2
		196	\& return 0;
		197	\& }
		198	.Ve
140	.SH "DESCRIPTION"	199	.SH "DESCRIPTION"
141	.IX Header "DESCRIPTION"	200	.IX Header "DESCRIPTION"
		201	The newest version of this document is also available as a html-formatted
		202	web page you might find easier to navigate when reading it for the first
		203	time: <http://cvs.schmorp.de/libev/ev.html>.
		204	.PP
142	Libev is an event loop: you register interest in certain events (such as a	205	Libev is an event loop: you register interest in certain events (such as a
143	file descriptor being readable or a timeout occuring), and it will manage	206	file descriptor being readable or a timeout occuring), and it will manage
144	these event sources and provide your program with events.	207	these event sources and provide your program with events.
145	.PP	208	.PP
146	To do this, it must take more or less complete control over your process	209	To do this, it must take more or less complete control over your process
…		…
151	watchers\fR, which are relatively small C structures you initialise with the	214	watchers\fR, which are relatively small C structures you initialise with the
152	details of the event, and then hand it over to libev by \fIstarting\fR the	215	details of the event, and then hand it over to libev by \fIstarting\fR the
153	watcher.	216	watcher.
154	.SH "FEATURES"	217	.SH "FEATURES"
155	.IX Header "FEATURES"	218	.IX Header "FEATURES"
156	Libev supports select, poll, the linux-specific epoll and the bsd-specific	219	Libev supports \f(CW\(C`select\(C'\fR, \f(CW\(C`poll\(C'\fR, the Linux-specific \f(CW\(C`epoll\(C'\fR, the
157	kqueue mechanisms for file descriptor events, relative timers, absolute	220	BSD-specific \f(CW\(C`kqueue\(C'\fR and the Solaris-specific event port mechanisms
158	timers with customised rescheduling, signal events, process status change	221	for file descriptor events (\f(CW\(C`ev_io\(C'\fR), the Linux \f(CW\(C`inotify\(C'\fR interface
159	events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event	222	(for \f(CW\(C`ev_stat\(C'\fR), relative timers (\f(CW\(C`ev_timer\(C'\fR), absolute timers
160	loop mechanism itself (idle, prepare and check watchers). It also is quite	223	with customised rescheduling (\f(CW\(C`ev_periodic\(C'\fR), synchronous signals
161	fast (see this benchmark comparing	224	(\f(CW\(C`ev_signal\(C'\fR), process status change events (\f(CW\(C`ev_child\(C'\fR), and event
162	it to libevent for example).	225	watchers dealing with the event loop mechanism itself (\f(CW\(C`ev_idle\(C'\fR,
		226	\&\f(CW\(C`ev_embed\(C'\fR, \f(CW\(C`ev_prepare\(C'\fR and \f(CW\(C`ev_check\(C'\fR watchers) as well as
		227	file watchers (\f(CW\(C`ev_stat\(C'\fR) and even limited support for fork events
		228	(\f(CW\(C`ev_fork\(C'\fR).
		229	.PP
		230	It also is quite fast (see this
		231	benchmark comparing it to libevent
		232	for example).
163	.SH "CONVENTIONS"	233	.SH "CONVENTIONS"
164	.IX Header "CONVENTIONS"	234	.IX Header "CONVENTIONS"
165	Libev is very configurable. In this manual the default configuration	235	Libev is very configurable. In this manual the default configuration will
166	will be described, which supports multiple event loops. For more info	236	be described, which supports multiple event loops. For more info about
167	about various configuration options please have a look at the file	237	various configuration options please have a look at \fB\s-1EMBED\s0\fR section in
168	\&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without	238	this manual. If libev was configured without support for multiple event
169	support for multiple event loops, then all functions taking an initial	239	loops, then all functions taking an initial argument of name \f(CW\(C`loop\(C'\fR
170	argument of name \f(CW\(C`loop\(C'\fR (which is always of type \f(CW\(C`struct ev_loop \*(C'\fR)	240	(which is always of type \f(CW\(C`struct ev_loop \*(C'\fR) will not have this argument.
171	will not have this argument.
172	.SH "TIME REPRESENTATION"	241	.SH "TIME REPRESENTATION"
173	.IX Header "TIME REPRESENTATION"	242	.IX Header "TIME REPRESENTATION"
174	Libev represents time as a single floating point number, representing the	243	Libev represents time as a single floating point number, representing the
175	(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near	244	(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near
176	the beginning of 1970, details are complicated, don't ask). This type is	245	the beginning of 1970, details are complicated, don't ask). This type is
…		…
201	Usually, it's a good idea to terminate if the major versions mismatch,	270	Usually, it's a good idea to terminate if the major versions mismatch,
202	as this indicates an incompatible change. Minor versions are usually	271	as this indicates an incompatible change. Minor versions are usually
203	compatible to older versions, so a larger minor version alone is usually	272	compatible to older versions, so a larger minor version alone is usually
204	not a problem.	273	not a problem.
205	.Sp	274	.Sp
206	Example: make sure we haven't accidentally been linked against the wrong	275	Example: Make sure we haven't accidentally been linked against the wrong
207	version:	276	version.
208	.Sp	277	.Sp
209	.Vb 3	278	.Vb 3
210	\& assert (("libev version mismatch",	279	\& assert (("libev version mismatch",
211	\& ev_version_major () == EV_VERSION_MAJOR	280	\& ev_version_major () == EV_VERSION_MAJOR
212	\& && ev_version_minor () >= EV_VERSION_MINOR));	281	\& && ev_version_minor () >= EV_VERSION_MINOR));
…		…
242	recommended ones.	311	recommended ones.
243	.Sp	312	.Sp
244	See the description of \f(CW\(C`ev_embed\(C'\fR watchers for more info.	313	See the description of \f(CW\(C`ev_embed\(C'\fR watchers for more info.
245	.IP "ev_set_allocator (void (cb)(void *ptr, long size))" 4	314	.IP "ev_set_allocator (void (cb)(void *ptr, long size))" 4
246	.IX Item "ev_set_allocator (void (cb)(void *ptr, long size))"	315	.IX Item "ev_set_allocator (void (cb)(void *ptr, long size))"
247	Sets the allocation function to use (the prototype is similar to the	316	Sets the allocation function to use (the prototype is similar \- the
248	realloc C function, the semantics are identical). It is used to allocate	317	semantics is identical \- to the realloc C function). It is used to
249	and free memory (no surprises here). If it returns zero when memory	318	allocate and free memory (no surprises here). If it returns zero when
250	needs to be allocated, the library might abort or take some potentially	319	memory needs to be allocated, the library might abort or take some
251	destructive action. The default is your system realloc function.	320	potentially destructive action. The default is your system realloc
		321	function.
252	.Sp	322	.Sp
253	You could override this function in high-availability programs to, say,	323	You could override this function in high-availability programs to, say,
254	free some memory if it cannot allocate memory, to use a special allocator,	324	free some memory if it cannot allocate memory, to use a special allocator,
255	or even to sleep a while and retry until some memory is available.	325	or even to sleep a while and retry until some memory is available.
256	.Sp	326	.Sp
257	Example: replace the libev allocator with one that waits a bit and then	327	Example: Replace the libev allocator with one that waits a bit and then
258	retries: better than mine).	328	retries).
259	.Sp	329	.Sp
260	.Vb 6	330	.Vb 6
261	\& static void *	331	\& static void *
262	\& persistent_realloc (void *ptr, long size)	332	\& persistent_realloc (void *ptr, size_t size)
263	\& {	333	\& {
264	\& for (;;)	334	\& for (;;)
265	\& {	335	\& {
266	\& void *newptr = realloc (ptr, size);	336	\& void *newptr = realloc (ptr, size);
267	.Ve	337	.Ve
…		…
289	callback is set, then libev will expect it to remedy the sitution, no	359	callback is set, then libev will expect it to remedy the sitution, no
290	matter what, when it returns. That is, libev will generally retry the	360	matter what, when it returns. That is, libev will generally retry the
291	requested operation, or, if the condition doesn't go away, do bad stuff	361	requested operation, or, if the condition doesn't go away, do bad stuff
292	(such as abort).	362	(such as abort).
293	.Sp	363	.Sp
294	Example: do the same thing as libev does internally:	364	Example: This is basically the same thing that libev does internally, too.
295	.Sp	365	.Sp
296	.Vb 6	366	.Vb 6
297	\& static void	367	\& static void
298	\& fatal_error (const char *msg)	368	\& fatal_error (const char *msg)
299	\& {	369	\& {
…		…
345	or setgid) then libev will \fInot\fR look at the environment variable	415	or setgid) then libev will \fInot\fR look at the environment variable
346	\&\f(CW\(C`LIBEV_FLAGS\(C'\fR. Otherwise (the default), this environment variable will	416	\&\f(CW\(C`LIBEV_FLAGS\(C'\fR. Otherwise (the default), this environment variable will
347	override the flags completely if it is found in the environment. This is	417	override the flags completely if it is found in the environment. This is
348	useful to try out specific backends to test their performance, or to work	418	useful to try out specific backends to test their performance, or to work
349	around bugs.	419	around bugs.
		420	.ie n .IP """EVFLAG_FORKCHECK""" 4
		421	.el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4
		422	.IX Item "EVFLAG_FORKCHECK"
		423	Instead of calling \f(CW\(C`ev_default_fork\(C'\fR or \f(CW\(C`ev_loop_fork\(C'\fR manually after
		424	a fork, you can also make libev check for a fork in each iteration by
		425	enabling this flag.
		426	.Sp
		427	This works by calling \f(CW\(C`getpid ()\(C'\fR on every iteration of the loop,
		428	and thus this might slow down your event loop if you do a lot of loop
		429	iterations and little real work, but is usually not noticeable (on my
		430	Linux system for example, \f(CW\(C`getpid\(C'\fR is actually a simple 5\-insn sequence
		431	without a syscall and thus \fIvery\fR fast, but my Linux system also has
		432	\&\f(CW\(C`pthread_atfork\(C'\fR which is even faster).
		433	.Sp
		434	The big advantage of this flag is that you can forget about fork (and
		435	forget about forgetting to tell libev about forking) when you use this
		436	flag.
		437	.Sp
		438	This flag setting cannot be overriden or specified in the \f(CW\(C`LIBEV_FLAGS\(C'\fR
		439	environment variable.
350	.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4	440	.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4
351	.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4	441	.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4
352	.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"	442	.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"
353	This is your standard \fIselect\fR\\|(2) backend. Not \fIcompletely\fR standard, as	443	This is your standard \fIselect\fR\\|(2) backend. Not \fIcompletely\fR standard, as
354	libev tries to roll its own fd_set with no limits on the number of fds,	444	libev tries to roll its own fd_set with no limits on the number of fds,
…		…
448	Similar to \f(CW\(C`ev_default_loop\(C'\fR, but always creates a new event loop that is	538	Similar to \f(CW\(C`ev_default_loop\(C'\fR, but always creates a new event loop that is
449	always distinct from the default loop. Unlike the default loop, it cannot	539	always distinct from the default loop. Unlike the default loop, it cannot
450	handle signal and child watchers, and attempts to do so will be greeted by	540	handle signal and child watchers, and attempts to do so will be greeted by
451	undefined behaviour (or a failed assertion if assertions are enabled).	541	undefined behaviour (or a failed assertion if assertions are enabled).
452	.Sp	542	.Sp
453	Example: try to create a event loop that uses epoll and nothing else.	543	Example: Try to create a event loop that uses epoll and nothing else.
454	.Sp	544	.Sp
455	.Vb 3	545	.Vb 3
456	\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	546	\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
457	\& if (!epoller)	547	\& if (!epoller)
458	\& fatal ("no epoll found here, maybe it hides under your chair");	548	\& fatal ("no epoll found here, maybe it hides under your chair");
…		…
495	.IP "ev_loop_fork (loop)" 4	585	.IP "ev_loop_fork (loop)" 4
496	.IX Item "ev_loop_fork (loop)"	586	.IX Item "ev_loop_fork (loop)"
497	Like \f(CW\(C`ev_default_fork\(C'\fR, but acts on an event loop created by	587	Like \f(CW\(C`ev_default_fork\(C'\fR, but acts on an event loop created by
498	\&\f(CW\(C`ev_loop_new\(C'\fR. Yes, you have to call this on every allocated event loop	588	\&\f(CW\(C`ev_loop_new\(C'\fR. Yes, you have to call this on every allocated event loop
499	after fork, and how you do this is entirely your own problem.	589	after fork, and how you do this is entirely your own problem.
		590	.IP "unsigned int ev_loop_count (loop)" 4
		591	.IX Item "unsigned int ev_loop_count (loop)"
		592	Returns the count of loop iterations for the loop, which is identical to
		593	the number of times libev did poll for new events. It starts at \f(CW0\fR and
		594	happily wraps around with enough iterations.
		595	.Sp
		596	This value can sometimes be useful as a generation counter of sorts (it
		597	\&\(L"ticks\(R" the number of loop iterations), as it roughly corresponds with
		598	\&\f(CW\(C`ev_prepare\(C'\fR and \f(CW\(C`ev_check\(C'\fR calls.
500	.IP "unsigned int ev_backend (loop)" 4	599	.IP "unsigned int ev_backend (loop)" 4
501	.IX Item "unsigned int ev_backend (loop)"	600	.IX Item "unsigned int ev_backend (loop)"
502	Returns one of the \f(CW\(C`EVBACKEND_\*(C'\fR flags indicating the event backend in	601	Returns one of the \f(CW\(C`EVBACKEND_\*(C'\fR flags indicating the event backend in
503	use.	602	use.
504	.IP "ev_tstamp ev_now (loop)" 4	603	.IP "ev_tstamp ev_now (loop)" 4
…		…
535	libev watchers. However, a pair of \f(CW\(C`ev_prepare\(C'\fR/\f(CW\(C`ev_check\(C'\fR watchers is	634	libev watchers. However, a pair of \f(CW\(C`ev_prepare\(C'\fR/\f(CW\(C`ev_check\(C'\fR watchers is
536	usually a better approach for this kind of thing.	635	usually a better approach for this kind of thing.
537	.Sp	636	.Sp
538	Here are the gory details of what \f(CW\(C`ev_loop\(C'\fR does:	637	Here are the gory details of what \f(CW\(C`ev_loop\(C'\fR does:
539	.Sp	638	.Sp
540	.Vb 18	639	.Vb 19
		640	\& - Before the first iteration, call any pending watchers.
541	\& * If there are no active watchers (reference count is zero), return.	641	\& * If there are no active watchers (reference count is zero), return.
542	\& - Queue prepare watchers and then call all outstanding watchers.	642	\& - Queue all prepare watchers and then call all outstanding watchers.
543	\& - If we have been forked, recreate the kernel state.	643	\& - If we have been forked, recreate the kernel state.
544	\& - Update the kernel state with all outstanding changes.	644	\& - Update the kernel state with all outstanding changes.
545	\& - Update the "event loop time".	645	\& - Update the "event loop time".
546	\& - Calculate for how long to block.	646	\& - Calculate for how long to block.
547	\& - Block the process, waiting for any events.	647	\& - Block the process, waiting for any events.
…		…
556	\& be handled here by queueing them when their watcher gets executed.	656	\& be handled here by queueing them when their watcher gets executed.
557	\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	657	\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
558	\& were used, return, otherwise continue with step *.	658	\& were used, return, otherwise continue with step *.
559	.Ve	659	.Ve
560	.Sp	660	.Sp
561	Example: queue some jobs and then loop until no events are outsanding	661	Example: Queue some jobs and then loop until no events are outsanding
562	anymore.	662	anymore.
563	.Sp	663	.Sp
564	.Vb 4	664	.Vb 4
565	\& ... queue jobs here, make sure they register event watchers as long	665	\& ... queue jobs here, make sure they register event watchers as long
566	\& ... as they still have work to do (even an idle watcher will do..)	666	\& ... as they still have work to do (even an idle watcher will do..)
…		…
588	visible to the libev user and should not keep \f(CW\(C`ev_loop\(C'\fR from exiting if	688	visible to the libev user and should not keep \f(CW\(C`ev_loop\(C'\fR from exiting if
589	no event watchers registered by it are active. It is also an excellent	689	no event watchers registered by it are active. It is also an excellent
590	way to do this for generic recurring timers or from within third-party	690	way to do this for generic recurring timers or from within third-party
591	libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.	691	libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.
592	.Sp	692	.Sp
593	Example: create a signal watcher, but keep it from keeping \f(CW\(C`ev_loop\(C'\fR	693	Example: Create a signal watcher, but keep it from keeping \f(CW\(C`ev_loop\(C'\fR
594	running when nothing else is active.	694	running when nothing else is active.
595	.Sp	695	.Sp
596	.Vb 4	696	.Vb 4
597	\& struct dv_signal exitsig;	697	\& struct ev_signal exitsig;
598	\& ev_signal_init (&exitsig, sig_cb, SIGINT);	698	\& ev_signal_init (&exitsig, sig_cb, SIGINT);
599	\& ev_signal_start (myloop, &exitsig);	699	\& ev_signal_start (loop, &exitsig);
600	\& evf_unref (myloop);	700	\& evf_unref (loop);
601	.Ve	701	.Ve
602	.Sp	702	.Sp
603	Example: for some weird reason, unregister the above signal handler again.	703	Example: For some weird reason, unregister the above signal handler again.
604	.Sp	704	.Sp
605	.Vb 2	705	.Vb 2
606	\& ev_ref (myloop);	706	\& ev_ref (loop);
607	\& ev_signal_stop (myloop, &exitsig);	707	\& ev_signal_stop (loop, &exitsig);
608	.Ve	708	.Ve
609	.SH "ANATOMY OF A WATCHER"	709	.SH "ANATOMY OF A WATCHER"
610	.IX Header "ANATOMY OF A WATCHER"	710	.IX Header "ANATOMY OF A WATCHER"
611	A watcher is a structure that you create and register to record your	711	A watcher is a structure that you create and register to record your
612	interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to	712	interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to
…		…
684	The signal specified in the \f(CW\(C`ev_signal\(C'\fR watcher has been received by a thread.	784	The signal specified in the \f(CW\(C`ev_signal\(C'\fR watcher has been received by a thread.
685	.ie n .IP """EV_CHILD""" 4	785	.ie n .IP """EV_CHILD""" 4
686	.el .IP "\f(CWEV_CHILD\fR" 4	786	.el .IP "\f(CWEV_CHILD\fR" 4
687	.IX Item "EV_CHILD"	787	.IX Item "EV_CHILD"
688	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.	788	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.
		789	.ie n .IP """EV_STAT""" 4
		790	.el .IP "\f(CWEV_STAT\fR" 4
		791	.IX Item "EV_STAT"
		792	The path specified in the \f(CW\(C`ev_stat\(C'\fR watcher changed its attributes somehow.
689	.ie n .IP """EV_IDLE""" 4	793	.ie n .IP """EV_IDLE""" 4
690	.el .IP "\f(CWEV_IDLE\fR" 4	794	.el .IP "\f(CWEV_IDLE\fR" 4
691	.IX Item "EV_IDLE"	795	.IX Item "EV_IDLE"
692	The \f(CW\(C`ev_idle\(C'\fR watcher has determined that you have nothing better to do.	796	The \f(CW\(C`ev_idle\(C'\fR watcher has determined that you have nothing better to do.
693	.ie n .IP """EV_PREPARE""" 4	797	.ie n .IP """EV_PREPARE""" 4
…		…
703	\&\f(CW\(C`ev_loop\(C'\fR has gathered them, but before it invokes any callbacks for any	807	\&\f(CW\(C`ev_loop\(C'\fR has gathered them, but before it invokes any callbacks for any
704	received events. Callbacks of both watcher types can start and stop as	808	received events. Callbacks of both watcher types can start and stop as
705	many watchers as they want, and all of them will be taken into account	809	many watchers as they want, and all of them will be taken into account
706	(for example, a \f(CW\(C`ev_prepare\(C'\fR watcher might start an idle watcher to keep	810	(for example, a \f(CW\(C`ev_prepare\(C'\fR watcher might start an idle watcher to keep
707	\&\f(CW\(C`ev_loop\(C'\fR from blocking).	811	\&\f(CW\(C`ev_loop\(C'\fR from blocking).
		812	.ie n .IP """EV_EMBED""" 4
		813	.el .IP "\f(CWEV_EMBED\fR" 4
		814	.IX Item "EV_EMBED"
		815	The embedded event loop specified in the \f(CW\(C`ev_embed\(C'\fR watcher needs attention.
		816	.ie n .IP """EV_FORK""" 4
		817	.el .IP "\f(CWEV_FORK\fR" 4
		818	.IX Item "EV_FORK"
		819	The event loop has been resumed in the child process after fork (see
		820	\&\f(CW\(C`ev_fork\(C'\fR).
708	.ie n .IP """EV_ERROR""" 4	821	.ie n .IP """EV_ERROR""" 4
709	.el .IP "\f(CWEV_ERROR\fR" 4	822	.el .IP "\f(CWEV_ERROR\fR" 4
710	.IX Item "EV_ERROR"	823	.IX Item "EV_ERROR"
711	An unspecified error has occured, the watcher has been stopped. This might	824	An unspecified error has occured, the watcher has been stopped. This might
712	happen because the watcher could not be properly started because libev	825	happen because the watcher could not be properly started because libev
…		…
777	.IP "bool ev_is_pending (ev_TYPE *watcher)" 4	890	.IP "bool ev_is_pending (ev_TYPE *watcher)" 4
778	.IX Item "bool ev_is_pending (ev_TYPE *watcher)"	891	.IX Item "bool ev_is_pending (ev_TYPE *watcher)"
779	Returns a true value iff the watcher is pending, (i.e. it has outstanding	892	Returns a true value iff the watcher is pending, (i.e. it has outstanding
780	events but its callback has not yet been invoked). As long as a watcher	893	events but its callback has not yet been invoked). As long as a watcher
781	is pending (but not active) you must not call an init function on it (but	894	is pending (but not active) you must not call an init function on it (but
782	\&\f(CW\(C`ev_TYPE_set\(C'\fR is safe) and you must make sure the watcher is available to	895	\&\f(CW\(C`ev_TYPE_set\(C'\fR is safe), you must not change its priority, and you must
783	libev (e.g. you cnanot \f(CW\(C`free ()\(C'\fR it).	896	make sure the watcher is available to libev (e.g. you cannot \f(CW\(C`free ()\(C'\fR
		897	it).
784	.IP "callback = ev_cb (ev_TYPE *watcher)" 4	898	.IP "callback ev_cb (ev_TYPE *watcher)" 4
785	.IX Item "callback = ev_cb (ev_TYPE *watcher)"	899	.IX Item "callback ev_cb (ev_TYPE *watcher)"
786	Returns the callback currently set on the watcher.	900	Returns the callback currently set on the watcher.
787	.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4	901	.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
788	.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"	902	.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
789	Change the callback. You can change the callback at virtually any time	903	Change the callback. You can change the callback at virtually any time
790	(modulo threads).	904	(modulo threads).
		905	.IP "ev_set_priority (ev_TYPE *watcher, priority)" 4
		906	.IX Item "ev_set_priority (ev_TYPE *watcher, priority)"
		907	.PD 0
		908	.IP "int ev_priority (ev_TYPE *watcher)" 4
		909	.IX Item "int ev_priority (ev_TYPE *watcher)"
		910	.PD
		911	Set and query the priority of the watcher. The priority is a small
		912	integer between \f(CW\(C`EV_MAXPRI\(C'\fR (default: \f(CW2\fR) and \f(CW\(C`EV_MINPRI\(C'\fR
		913	(default: \f(CW\(C`\-2\(C'\fR). Pending watchers with higher priority will be invoked
		914	before watchers with lower priority, but priority will not keep watchers
		915	from being executed (except for \f(CW\(C`ev_idle\(C'\fR watchers).
		916	.Sp
		917	This means that priorities are \fIonly\fR used for ordering callback
		918	invocation after new events have been received. This is useful, for
		919	example, to reduce latency after idling, or more often, to bind two
		920	watchers on the same event and make sure one is called first.
		921	.Sp
		922	If you need to suppress invocation when higher priority events are pending
		923	you need to look at \f(CW\(C`ev_idle\(C'\fR watchers, which provide this functionality.
		924	.Sp
		925	You \fImust not\fR change the priority of a watcher as long as it is active or
		926	pending.
		927	.Sp
		928	The default priority used by watchers when no priority has been set is
		929	always \f(CW0\fR, which is supposed to not be too high and not be too low :).
		930	.Sp
		931	Setting a priority outside the range of \f(CW\(C`EV_MINPRI\(C'\fR to \f(CW\(C`EV_MAXPRI\(C'\fR is
		932	fine, as long as you do not mind that the priority value you query might
		933	or might not have been adjusted to be within valid range.
		934	.IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4
		935	.IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)"
		936	Invoke the \f(CW\(C`watcher\(C'\fR with the given \f(CW\(C`loop\(C'\fR and \f(CW\(C`revents\(C'\fR. Neither
		937	\&\f(CW\(C`loop\(C'\fR nor \f(CW\(C`revents\(C'\fR need to be valid as long as the watcher callback
		938	can deal with that fact.
		939	.IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4
		940	.IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)"
		941	If the watcher is pending, this function returns clears its pending status
		942	and returns its \f(CW\(C`revents\(C'\fR bitset (as if its callback was invoked). If the
		943	watcher isn't pending it does nothing and returns \f(CW0\fR.
791	.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"	944	.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"
792	.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"	945	.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
793	Each watcher has, by default, a member \f(CW\(C`void data\*(C'\fR that you can change	946	Each watcher has, by default, a member \f(CW\(C`void data\*(C'\fR that you can change
794	and read at any time, libev will completely ignore it. This can be used	947	and read at any time, libev will completely ignore it. This can be used
795	to associate arbitrary data with your watcher. If you need more data and	948	to associate arbitrary data with your watcher. If you need more data and
…		…
816	\& struct my_io w = (struct my_io )w_;	969	\& struct my_io w = (struct my_io )w_;
817	\& ...	970	\& ...
818	\& }	971	\& }
819	.Ve	972	.Ve
820	.PP	973	.PP
821	More interesting and less C\-conformant ways of catsing your callback type	974	More interesting and less C\-conformant ways of casting your callback type
822	have been omitted....	975	instead have been omitted.
		976	.PP
		977	Another common scenario is having some data structure with multiple
		978	watchers:
		979	.PP
		980	.Vb 6
		981	\& struct my_biggy
		982	\& {
		983	\& int some_data;
		984	\& ev_timer t1;
		985	\& ev_timer t2;
		986	\& }
		987	.Ve
		988	.PP
		989	In this case getting the pointer to \f(CW\(C`my_biggy\(C'\fR is a bit more complicated,
		990	you need to use \f(CW\(C`offsetof\(C'\fR:
		991	.PP
		992	.Vb 1
		993	\& #include <stddef.h>
		994	.Ve
		995	.PP
		996	.Vb 6
		997	\& static void
		998	\& t1_cb (EV_P_ struct ev_timer *w, int revents)
		999	\& {
		1000	\& struct my_biggy big = (struct my_biggy *
		1001	\& (((char *)w) - offsetof (struct my_biggy, t1));
		1002	\& }
		1003	.Ve
		1004	.PP
		1005	.Vb 6
		1006	\& static void
		1007	\& t2_cb (EV_P_ struct ev_timer *w, int revents)
		1008	\& {
		1009	\& struct my_biggy big = (struct my_biggy *
		1010	\& (((char *)w) - offsetof (struct my_biggy, t2));
		1011	\& }
		1012	.Ve
823	.SH "WATCHER TYPES"	1013	.SH "WATCHER TYPES"
824	.IX Header "WATCHER TYPES"	1014	.IX Header "WATCHER TYPES"
825	This section describes each watcher in detail, but will not repeat	1015	This section describes each watcher in detail, but will not repeat
826	information given in the last section.	1016	information given in the last section. Any initialisation/set macros,
		1017	functions and members specific to the watcher type are explained.
		1018	.PP
		1019	Members are additionally marked with either \fI[read\-only]\fR, meaning that,
		1020	while the watcher is active, you can look at the member and expect some
		1021	sensible content, but you must not modify it (you can modify it while the
		1022	watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
		1023	means you can expect it to have some sensible content while the watcher
		1024	is active, but you can also modify it. Modifying it may not do something
		1025	sensible or take immediate effect (or do anything at all), but libev will
		1026	not crash or malfunction in any way.
827	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable?"	1027	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable?"
828	.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?"	1028	.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?"
829	.IX Subsection "ev_io - is this file descriptor readable or writable?"	1029	.IX Subsection "ev_io - is this file descriptor readable or writable?"
830	I/O watchers check whether a file descriptor is readable or writable	1030	I/O watchers check whether a file descriptor is readable or writable
831	in each iteration of the event loop, or, more precisely, when reading	1031	in each iteration of the event loop, or, more precisely, when reading
…		…
859	it is best to always use non-blocking I/O: An extra \f(CW\(C`read\(C'\fR(2) returning	1059	it is best to always use non-blocking I/O: An extra \f(CW\(C`read\(C'\fR(2) returning
860	\&\f(CW\(C`EAGAIN\(C'\fR is far preferable to a program hanging until some data arrives.	1060	\&\f(CW\(C`EAGAIN\(C'\fR is far preferable to a program hanging until some data arrives.
861	.PP	1061	.PP
862	If you cannot run the fd in non-blocking mode (for example you should not	1062	If you cannot run the fd in non-blocking mode (for example you should not
863	play around with an Xlib connection), then you have to seperately re-test	1063	play around with an Xlib connection), then you have to seperately re-test
864	wether a file descriptor is really ready with a known-to-be good interface	1064	whether a file descriptor is really ready with a known-to-be good interface
865	such as poll (fortunately in our Xlib example, Xlib already does this on	1065	such as poll (fortunately in our Xlib example, Xlib already does this on
866	its own, so its quite safe to use).	1066	its own, so its quite safe to use).
867	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4	1067	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
868	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"	1068	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
869	.PD 0	1069	.PD 0
…		…
871	.IX Item "ev_io_set (ev_io *, int fd, int events)"	1071	.IX Item "ev_io_set (ev_io *, int fd, int events)"
872	.PD	1072	.PD
873	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The \f(CW\(C`fd\(C'\fR is the file descriptor to	1073	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The \f(CW\(C`fd\(C'\fR is the file descriptor to
874	rceeive events for and events is either \f(CW\(C`EV_READ\(C'\fR, \f(CW\(C`EV_WRITE\(C'\fR or	1074	rceeive events for and events is either \f(CW\(C`EV_READ\(C'\fR, \f(CW\(C`EV_WRITE\(C'\fR or
875	\&\f(CW\(C`EV_READ \| EV_WRITE\(C'\fR to receive the given events.	1075	\&\f(CW\(C`EV_READ \| EV_WRITE\(C'\fR to receive the given events.
		1076	.IP "int fd [read\-only]" 4
		1077	.IX Item "int fd [read-only]"
		1078	The file descriptor being watched.
		1079	.IP "int events [read\-only]" 4
		1080	.IX Item "int events [read-only]"
		1081	The events being watched.
876	.PP	1082	.PP
877	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well	1083	Example: Call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well
878	readable, but only once. Since it is likely line\-buffered, you could	1084	readable, but only once. Since it is likely line\-buffered, you could
879	attempt to read a whole line in the callback:	1085	attempt to read a whole line in the callback.
880	.PP	1086	.PP
881	.Vb 6	1087	.Vb 6
882	\& static void	1088	\& static void
883	\& stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	1089	\& stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
884	\& {	1090	\& {
…		…
939	.IP "ev_timer_again (loop)" 4	1145	.IP "ev_timer_again (loop)" 4
940	.IX Item "ev_timer_again (loop)"	1146	.IX Item "ev_timer_again (loop)"
941	This will act as if the timer timed out and restart it again if it is	1147	This will act as if the timer timed out and restart it again if it is
942	repeating. The exact semantics are:	1148	repeating. The exact semantics are:
943	.Sp	1149	.Sp
		1150	If the timer is pending, its pending status is cleared.
		1151	.Sp
944	If the timer is started but nonrepeating, stop it.	1152	If the timer is started but nonrepeating, stop it (as if it timed out).
945	.Sp	1153	.Sp
946	If the timer is repeating, either start it if necessary (with the repeat	1154	If the timer is repeating, either start it if necessary (with the
947	value), or reset the running timer to the repeat value.	1155	\&\f(CW\(C`repeat\(C'\fR value), or reset the running timer to the \f(CW\(C`repeat\(C'\fR value.
948	.Sp	1156	.Sp
949	This sounds a bit complicated, but here is a useful and typical	1157	This sounds a bit complicated, but here is a useful and typical
950	example: Imagine you have a tcp connection and you want a so-called idle	1158	example: Imagine you have a tcp connection and you want a so-called idle
951	timeout, that is, you want to be called when there have been, say, 60	1159	timeout, that is, you want to be called when there have been, say, 60
952	seconds of inactivity on the socket. The easiest way to do this is to	1160	seconds of inactivity on the socket. The easiest way to do this is to
953	configure an \f(CW\(C`ev_timer\(C'\fR with after=repeat=60 and calling ev_timer_again each	1161	configure an \f(CW\(C`ev_timer\(C'\fR with a \f(CW\(C`repeat\(C'\fR value of \f(CW60\fR and then call
954	time you successfully read or write some data. If you go into an idle	1162	\&\f(CW\(C`ev_timer_again\(C'\fR each time you successfully read or write some data. If
955	state where you do not expect data to travel on the socket, you can stop	1163	you go into an idle state where you do not expect data to travel on the
956	the timer, and again will automatically restart it if need be.	1164	socket, you can \f(CW\(C`ev_timer_stop\(C'\fR the timer, and \f(CW\(C`ev_timer_again\(C'\fR will
		1165	automatically restart it if need be.
		1166	.Sp
		1167	That means you can ignore the \f(CW\(C`after\(C'\fR value and \f(CW\(C`ev_timer_start\(C'\fR
		1168	altogether and only ever use the \f(CW\(C`repeat\(C'\fR value and \f(CW\(C`ev_timer_again\(C'\fR:
		1169	.Sp
		1170	.Vb 8
		1171	\& ev_timer_init (timer, callback, 0., 5.);
		1172	\& ev_timer_again (loop, timer);
		1173	\& ...
		1174	\& timer->again = 17.;
		1175	\& ev_timer_again (loop, timer);
		1176	\& ...
		1177	\& timer->again = 10.;
		1178	\& ev_timer_again (loop, timer);
		1179	.Ve
		1180	.Sp
		1181	This is more slightly efficient then stopping/starting the timer each time
		1182	you want to modify its timeout value.
		1183	.IP "ev_tstamp repeat [read\-write]" 4
		1184	.IX Item "ev_tstamp repeat [read-write]"
		1185	The current \f(CW\(C`repeat\(C'\fR value. Will be used each time the watcher times out
		1186	or \f(CW\(C`ev_timer_again\(C'\fR is called and determines the next timeout (if any),
		1187	which is also when any modifications are taken into account.
957	.PP	1188	.PP
958	Example: create a timer that fires after 60 seconds.	1189	Example: Create a timer that fires after 60 seconds.
959	.PP	1190	.PP
960	.Vb 5	1191	.Vb 5
961	\& static void	1192	\& static void
962	\& one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1193	\& one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
963	\& {	1194	\& {
…		…
969	\& struct ev_timer mytimer;	1200	\& struct ev_timer mytimer;
970	\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1201	\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
971	\& ev_timer_start (loop, &mytimer);	1202	\& ev_timer_start (loop, &mytimer);
972	.Ve	1203	.Ve
973	.PP	1204	.PP
974	Example: create a timeout timer that times out after 10 seconds of	1205	Example: Create a timeout timer that times out after 10 seconds of
975	inactivity.	1206	inactivity.
976	.PP	1207	.PP
977	.Vb 5	1208	.Vb 5
978	\& static void	1209	\& static void
979	\& timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1210	\& timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
…		…
1093	.IX Item "ev_periodic_again (loop, ev_periodic *)"	1324	.IX Item "ev_periodic_again (loop, ev_periodic *)"
1094	Simply stops and restarts the periodic watcher again. This is only useful	1325	Simply stops and restarts the periodic watcher again. This is only useful
1095	when you changed some parameters or the reschedule callback would return	1326	when you changed some parameters or the reschedule callback would return
1096	a different time than the last time it was called (e.g. in a crond like	1327	a different time than the last time it was called (e.g. in a crond like
1097	program when the crontabs have changed).	1328	program when the crontabs have changed).
		1329	.IP "ev_tstamp interval [read\-write]" 4
		1330	.IX Item "ev_tstamp interval [read-write]"
		1331	The current interval value. Can be modified any time, but changes only
		1332	take effect when the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being
		1333	called.
		1334	.IP "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read\-write]" 4
		1335	.IX Item "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]"
		1336	The current reschedule callback, or \f(CW0\fR, if this functionality is
		1337	switched off. Can be changed any time, but changes only take effect when
		1338	the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being called.
1098	.PP	1339	.PP
1099	Example: call a callback every hour, or, more precisely, whenever the	1340	Example: Call a callback every hour, or, more precisely, whenever the
1100	system clock is divisible by 3600. The callback invocation times have	1341	system clock is divisible by 3600. The callback invocation times have
1101	potentially a lot of jittering, but good long-term stability.	1342	potentially a lot of jittering, but good long-term stability.
1102	.PP	1343	.PP
1103	.Vb 5	1344	.Vb 5
1104	\& static void	1345	\& static void
…		…
1112	\& struct ev_periodic hourly_tick;	1353	\& struct ev_periodic hourly_tick;
1113	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1354	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1114	\& ev_periodic_start (loop, &hourly_tick);	1355	\& ev_periodic_start (loop, &hourly_tick);
1115	.Ve	1356	.Ve
1116	.PP	1357	.PP
1117	Example: the same as above, but use a reschedule callback to do it:	1358	Example: The same as above, but use a reschedule callback to do it:
1118	.PP	1359	.PP
1119	.Vb 1	1360	.Vb 1
1120	\& #include <math.h>	1361	\& #include <math.h>
1121	.Ve	1362	.Ve
1122	.PP	1363	.PP
…		…
1130	.PP	1371	.PP
1131	.Vb 1	1372	.Vb 1
1132	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1373	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1133	.Ve	1374	.Ve
1134	.PP	1375	.PP
1135	Example: call a callback every hour, starting now:	1376	Example: Call a callback every hour, starting now:
1136	.PP	1377	.PP
1137	.Vb 4	1378	.Vb 4
1138	\& struct ev_periodic hourly_tick;	1379	\& struct ev_periodic hourly_tick;
1139	\& ev_periodic_init (&hourly_tick, clock_cb,	1380	\& ev_periodic_init (&hourly_tick, clock_cb,
1140	\& fmod (ev_now (loop), 3600.), 3600., 0);	1381	\& fmod (ev_now (loop), 3600.), 3600., 0);
…		…
1160	.IP "ev_signal_set (ev_signal *, int signum)" 4	1401	.IP "ev_signal_set (ev_signal *, int signum)" 4
1161	.IX Item "ev_signal_set (ev_signal *, int signum)"	1402	.IX Item "ev_signal_set (ev_signal *, int signum)"
1162	.PD	1403	.PD
1163	Configures the watcher to trigger on the given signal number (usually one	1404	Configures the watcher to trigger on the given signal number (usually one
1164	of the \f(CW\(C`SIGxxx\(C'\fR constants).	1405	of the \f(CW\(C`SIGxxx\(C'\fR constants).
		1406	.IP "int signum [read\-only]" 4
		1407	.IX Item "int signum [read-only]"
		1408	The signal the watcher watches out for.
1165	.ie n .Sh """ev_child"" \- watch out for process status changes"	1409	.ie n .Sh """ev_child"" \- watch out for process status changes"
1166	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"	1410	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1167	.IX Subsection "ev_child - watch out for process status changes"	1411	.IX Subsection "ev_child - watch out for process status changes"
1168	Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to	1412	Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
1169	some child status changes (most typically when a child of yours dies).	1413	some child status changes (most typically when a child of yours dies).
…		…
1177	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look	1421	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look
1178	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see	1422	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see
1179	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems	1423	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems
1180	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the	1424	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the
1181	process causing the status change.	1425	process causing the status change.
		1426	.IP "int pid [read\-only]" 4
		1427	.IX Item "int pid [read-only]"
		1428	The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
		1429	.IP "int rpid [read\-write]" 4
		1430	.IX Item "int rpid [read-write]"
		1431	The process id that detected a status change.
		1432	.IP "int rstatus [read\-write]" 4
		1433	.IX Item "int rstatus [read-write]"
		1434	The process exit/trace status caused by \f(CW\(C`rpid\(C'\fR (see your systems
		1435	\&\f(CW\(C`waitpid\(C'\fR and \f(CW\(C`sys/wait.h\(C'\fR documentation for details).
1182	.PP	1436	.PP
1183	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.	1437	Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1184	.PP	1438	.PP
1185	.Vb 5	1439	.Vb 5
1186	\& static void	1440	\& static void
1187	\& sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1441	\& sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1188	\& {	1442	\& {
…		…
1193	.Vb 3	1447	.Vb 3
1194	\& struct ev_signal signal_watcher;	1448	\& struct ev_signal signal_watcher;
1195	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1449	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1196	\& ev_signal_start (loop, &sigint_cb);	1450	\& ev_signal_start (loop, &sigint_cb);
1197	.Ve	1451	.Ve
		1452	.ie n .Sh """ev_stat"" \- did the file attributes just change?"
		1453	.el .Sh "\f(CWev_stat\fP \- did the file attributes just change?"
		1454	.IX Subsection "ev_stat - did the file attributes just change?"
		1455	This watches a filesystem path for attribute changes. That is, it calls
		1456	\&\f(CW\(C`stat\(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed
		1457	compared to the last time, invoking the callback if it did.
		1458	.PP
		1459	The path does not need to exist: changing from \(L"path exists\(R" to \*(L"path does
		1460	not exist\(R" is a status change like any other. The condition \(L"path does
		1461	not exist\(R" is signified by the \f(CW\(C`st_nlink\*(C'\fR field being zero (which is
		1462	otherwise always forced to be at least one) and all the other fields of
		1463	the stat buffer having unspecified contents.
		1464	.PP
		1465	The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is
		1466	relative and your working directory changes, the behaviour is undefined.
		1467	.PP
		1468	Since there is no standard to do this, the portable implementation simply
		1469	calls \f(CW\(C`stat (2)\(C'\fR regularly on the path to see if it changed somehow. You
		1470	can specify a recommended polling interval for this case. If you specify
		1471	a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
		1472	unspecified default\fR value will be used (which you can expect to be around
		1473	five seconds, although this might change dynamically). Libev will also
		1474	impose a minimum interval which is currently around \f(CW0.1\fR, but thats
		1475	usually overkill.
		1476	.PP
		1477	This watcher type is not meant for massive numbers of stat watchers,
		1478	as even with OS-supported change notifications, this can be
		1479	resource\-intensive.
		1480	.PP
		1481	At the time of this writing, only the Linux inotify interface is
		1482	implemented (implementing kqueue support is left as an exercise for the
		1483	reader). Inotify will be used to give hints only and should not change the
		1484	semantics of \f(CW\(C`ev_stat\(C'\fR watchers, which means that libev sometimes needs
		1485	to fall back to regular polling again even with inotify, but changes are
		1486	usually detected immediately, and if the file exists there will be no
		1487	polling.
		1488	.IP "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)" 4
		1489	.IX Item "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)"
		1490	.PD 0
		1491	.IP "ev_stat_set (ev_stat , const char path, ev_tstamp interval)" 4
		1492	.IX Item "ev_stat_set (ev_stat , const char path, ev_tstamp interval)"
		1493	.PD
		1494	Configures the watcher to wait for status changes of the given
		1495	\&\f(CW\(C`path\(C'\fR. The \f(CW\(C`interval\(C'\fR is a hint on how quickly a change is expected to
		1496	be detected and should normally be specified as \f(CW0\fR to let libev choose
		1497	a suitable value. The memory pointed to by \f(CW\(C`path\(C'\fR must point to the same
		1498	path for as long as the watcher is active.
		1499	.Sp
		1500	The callback will be receive \f(CW\(C`EV_STAT\(C'\fR when a change was detected,
		1501	relative to the attributes at the time the watcher was started (or the
		1502	last change was detected).
		1503	.IP "ev_stat_stat (ev_stat *)" 4
		1504	.IX Item "ev_stat_stat (ev_stat *)"
		1505	Updates the stat buffer immediately with new values. If you change the
		1506	watched path in your callback, you could call this fucntion to avoid
		1507	detecting this change (while introducing a race condition). Can also be
		1508	useful simply to find out the new values.
		1509	.IP "ev_statdata attr [read\-only]" 4
		1510	.IX Item "ev_statdata attr [read-only]"
		1511	The most-recently detected attributes of the file. Although the type is of
		1512	\&\f(CW\(C`ev_statdata\(C'\fR, this is usually the (or one of the) \f(CW\(C`struct stat\(C'\fR types
		1513	suitable for your system. If the \f(CW\(C`st_nlink\(C'\fR member is \f(CW0\fR, then there
		1514	was some error while \f(CW\(C`stat\(C'\fRing the file.
		1515	.IP "ev_statdata prev [read\-only]" 4
		1516	.IX Item "ev_statdata prev [read-only]"
		1517	The previous attributes of the file. The callback gets invoked whenever
		1518	\&\f(CW\(C`prev\(C'\fR != \f(CW\(C`attr\(C'\fR.
		1519	.IP "ev_tstamp interval [read\-only]" 4
		1520	.IX Item "ev_tstamp interval [read-only]"
		1521	The specified interval.
		1522	.IP "const char *path [read\-only]" 4
		1523	.IX Item "const char *path [read-only]"
		1524	The filesystem path that is being watched.
		1525	.PP
		1526	Example: Watch \f(CW\(C`/etc/passwd\(C'\fR for attribute changes.
		1527	.PP
		1528	.Vb 15
		1529	\& static void
		1530	\& passwd_cb (struct ev_loop loop, ev_stat w, int revents)
		1531	\& {
		1532	\& /* /etc/passwd changed in some way */
		1533	\& if (w->attr.st_nlink)
		1534	\& {
		1535	\& printf ("passwd current size %ld\en", (long)w->attr.st_size);
		1536	\& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime);
		1537	\& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime);
		1538	\& }
		1539	\& else
		1540	\& /* you shalt not abuse printf for puts */
		1541	\& puts ("wow, /etc/passwd is not there, expect problems. "
		1542	\& "if this is windows, they already arrived\en");
		1543	\& }
		1544	.Ve
		1545	.PP
		1546	.Vb 2
		1547	\& ...
		1548	\& ev_stat passwd;
		1549	.Ve
		1550	.PP
		1551	.Vb 2
		1552	\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
		1553	\& ev_stat_start (loop, &passwd);
		1554	.Ve
1198	.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."	1555	.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
1199	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."	1556	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
1200	.IX Subsection "ev_idle - when you've got nothing better to do..."	1557	.IX Subsection "ev_idle - when you've got nothing better to do..."
1201	Idle watchers trigger events when there are no other events are pending	1558	Idle watchers trigger events when no other events of the same or higher
1202	(prepare, check and other idle watchers do not count). That is, as long	1559	priority are pending (prepare, check and other idle watchers do not
1203	as your process is busy handling sockets or timeouts (or even signals,	1560	count).
1204	imagine) it will not be triggered. But when your process is idle all idle	1561	.PP
1205	watchers are being called again and again, once per event loop iteration \-	1562	That is, as long as your process is busy handling sockets or timeouts
		1563	(or even signals, imagine) of the same or higher priority it will not be
		1564	triggered. But when your process is idle (or only lower-priority watchers
		1565	are pending), the idle watchers are being called once per event loop
1206	until stopped, that is, or your process receives more events and becomes	1566	iteration \- until stopped, that is, or your process receives more events
1207	busy.	1567	and becomes busy again with higher priority stuff.
1208	.PP	1568	.PP
1209	The most noteworthy effect is that as long as any idle watchers are	1569	The most noteworthy effect is that as long as any idle watchers are
1210	active, the process will not block when waiting for new events.	1570	active, the process will not block when waiting for new events.
1211	.PP	1571	.PP
1212	Apart from keeping your process non-blocking (which is a useful	1572	Apart from keeping your process non-blocking (which is a useful
…		…
1217	.IX Item "ev_idle_init (ev_signal *, callback)"	1577	.IX Item "ev_idle_init (ev_signal *, callback)"
1218	Initialises and configures the idle watcher \- it has no parameters of any	1578	Initialises and configures the idle watcher \- it has no parameters of any
1219	kind. There is a \f(CW\(C`ev_idle_set\(C'\fR macro, but using it is utterly pointless,	1579	kind. There is a \f(CW\(C`ev_idle_set\(C'\fR macro, but using it is utterly pointless,
1220	believe me.	1580	believe me.
1221	.PP	1581	.PP
1222	Example: dynamically allocate an \f(CW\(C`ev_idle\(C'\fR, start it, and in the	1582	Example: Dynamically allocate an \f(CW\(C`ev_idle\(C'\fR watcher, start it, and in the
1223	callback, free it. Alos, use no error checking, as usual.	1583	callback, free it. Also, use no error checking, as usual.
1224	.PP	1584	.PP
1225	.Vb 7	1585	.Vb 7
1226	\& static void	1586	\& static void
1227	\& idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1587	\& idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1228	\& {	1588	\& {
…		…
1275	are ready to run (it's actually more complicated: it only runs coroutines	1635	are ready to run (it's actually more complicated: it only runs coroutines
1276	with priority higher than or equal to the event loop and one coroutine	1636	with priority higher than or equal to the event loop and one coroutine
1277	of lower priority, but only once, using idle watchers to keep the event	1637	of lower priority, but only once, using idle watchers to keep the event
1278	loop from blocking if lower-priority coroutines are active, thus mapping	1638	loop from blocking if lower-priority coroutines are active, thus mapping
1279	low-priority coroutines to idle/background tasks).	1639	low-priority coroutines to idle/background tasks).
		1640	.PP
		1641	It is recommended to give \f(CW\(C`ev_check\(C'\fR watchers highest (\f(CW\(C`EV_MAXPRI\(C'\fR)
		1642	priority, to ensure that they are being run before any other watchers
		1643	after the poll. Also, \f(CW\(C`ev_check\(C'\fR watchers (and \f(CW\(C`ev_prepare\(C'\fR watchers,
		1644	too) should not activate (\(L"feed\(R") events into libev. While libev fully
		1645	supports this, they will be called before other \f(CW\(C`ev_check\(C'\fR watchers did
		1646	their job. As \f(CW\(C`ev_check\(C'\fR watchers are often used to embed other event
		1647	loops those other event loops might be in an unusable state until their
		1648	\&\f(CW\(C`ev_check\(C'\fR watcher ran (always remind yourself to coexist peacefully with
		1649	others).
1280	.IP "ev_prepare_init (ev_prepare *, callback)" 4	1650	.IP "ev_prepare_init (ev_prepare *, callback)" 4
1281	.IX Item "ev_prepare_init (ev_prepare *, callback)"	1651	.IX Item "ev_prepare_init (ev_prepare *, callback)"
1282	.PD 0	1652	.PD 0
1283	.IP "ev_check_init (ev_check *, callback)" 4	1653	.IP "ev_check_init (ev_check *, callback)" 4
1284	.IX Item "ev_check_init (ev_check *, callback)"	1654	.IX Item "ev_check_init (ev_check *, callback)"
1285	.PD	1655	.PD
1286	Initialises and configures the prepare or check watcher \- they have no	1656	Initialises and configures the prepare or check watcher \- they have no
1287	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR	1657	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR
1288	macros, but using them is utterly, utterly and completely pointless.	1658	macros, but using them is utterly, utterly and completely pointless.
1289	.PP	1659	.PP
1290	Example: To include a library such as adns, you would add \s-1IO\s0 watchers	1660	There are a number of principal ways to embed other event loops or modules
1291	and a timeout watcher in a prepare handler, as required by libadns, and	1661	into libev. Here are some ideas on how to include libadns into libev
		1662	(there is a Perl module named \f(CW\(C`EV::ADNS\(C'\fR that does this, which you could
		1663	use for an actually working example. Another Perl module named \f(CW\(C`EV::Glib\(C'\fR
		1664	embeds a Glib main context into libev, and finally, \f(CW\(C`Glib::EV\(C'\fR embeds \s-1EV\s0
		1665	into the Glib event loop).
		1666	.PP
		1667	Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler,
1292	in a check watcher, destroy them and call into libadns. What follows is	1668	and in a check watcher, destroy them and call into libadns. What follows
1293	pseudo-code only of course:	1669	is pseudo-code only of course. This requires you to either use a low
		1670	priority for the check watcher or use \f(CW\(C`ev_clear_pending\(C'\fR explicitly, as
		1671	the callbacks for the IO/timeout watchers might not have been called yet.
1294	.PP	1672	.PP
1295	.Vb 2	1673	.Vb 2
1296	\& static ev_io iow [nfd];	1674	\& static ev_io iow [nfd];
1297	\& static ev_timer tw;	1675	\& static ev_timer tw;
1298	.Ve	1676	.Ve
1299	.PP	1677	.PP
1300	.Vb 9	1678	.Vb 4
1301	\& static void	1679	\& static void
1302	\& io_cb (ev_loop loop, ev_io w, int revents)	1680	\& io_cb (ev_loop loop, ev_io w, int revents)
1303	\& {	1681	\& {
1304	\& // set the relevant poll flags
1305	\& // could also call adns_processreadable etc. here
1306	\& struct pollfd fd = (struct pollfd )w->data;
1307	\& if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1308	\& if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
1309	\& }	1682	\& }
1310	.Ve	1683	.Ve
1311	.PP	1684	.PP
1312	.Vb 7	1685	.Vb 8
1313	\& // create io watchers for each fd and a timer before blocking	1686	\& // create io watchers for each fd and a timer before blocking
1314	\& static void	1687	\& static void
1315	\& adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1688	\& adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1316	\& {	1689	\& {
1317	\& int timeout = 3600000;truct pollfd fds [nfd];	1690	\& int timeout = 3600000;
		1691	\& struct pollfd fds [nfd];
1318	\& // actual code will need to loop here and realloc etc.	1692	\& // actual code will need to loop here and realloc etc.
1319	\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1693	\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1320	.Ve	1694	.Ve
1321	.PP	1695	.PP
1322	.Vb 3	1696	.Vb 3
…		…
1324	\& ev_timer_init (&tw, 0, timeout * 1e-3);	1698	\& ev_timer_init (&tw, 0, timeout * 1e-3);
1325	\& ev_timer_start (loop, &tw);	1699	\& ev_timer_start (loop, &tw);
1326	.Ve	1700	.Ve
1327	.PP	1701	.PP
1328	.Vb 6	1702	.Vb 6
1329	\& // create on ev_io per pollfd	1703	\& // create one ev_io per pollfd
1330	\& for (int i = 0; i < nfd; ++i)	1704	\& for (int i = 0; i < nfd; ++i)
1331	\& {	1705	\& {
1332	\& ev_io_init (iow + i, io_cb, fds [i].fd,	1706	\& ev_io_init (iow + i, io_cb, fds [i].fd,
1333	\& ((fds [i].events & POLLIN ? EV_READ : 0)	1707	\& ((fds [i].events & POLLIN ? EV_READ : 0)
1334	\& \| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	1708	\& \| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1335	.Ve	1709	.Ve
1336	.PP	1710	.PP
1337	.Vb 5	1711	.Vb 4
1338	\& fds [i].revents = 0;	1712	\& fds [i].revents = 0;
1339	\& iow [i].data = fds + i;
1340	\& ev_io_start (loop, iow + i);	1713	\& ev_io_start (loop, iow + i);
1341	\& }	1714	\& }
1342	\& }	1715	\& }
1343	.Ve	1716	.Ve
1344	.PP	1717	.PP
…		…
1348	\& adns_check_cb (ev_loop loop, ev_check w, int revents)	1721	\& adns_check_cb (ev_loop loop, ev_check w, int revents)
1349	\& {	1722	\& {
1350	\& ev_timer_stop (loop, &tw);	1723	\& ev_timer_stop (loop, &tw);
1351	.Ve	1724	.Ve
1352	.PP	1725	.PP
1353	.Vb 2	1726	.Vb 8
1354	\& for (int i = 0; i < nfd; ++i)	1727	\& for (int i = 0; i < nfd; ++i)
		1728	\& {
		1729	\& // set the relevant poll flags
		1730	\& // could also call adns_processreadable etc. here
		1731	\& struct pollfd *fd = fds + i;
		1732	\& int revents = ev_clear_pending (iow + i);
		1733	\& if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1734	\& if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1735	.Ve
		1736	.PP
		1737	.Vb 3
		1738	\& // now stop the watcher
1355	\& ev_io_stop (loop, iow + i);	1739	\& ev_io_stop (loop, iow + i);
		1740	\& }
1356	.Ve	1741	.Ve
1357	.PP	1742	.PP
1358	.Vb 2	1743	.Vb 2
1359	\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	1744	\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1745	\& }
		1746	.Ve
		1747	.PP
		1748	Method 2: This would be just like method 1, but you run \f(CW\(C`adns_afterpoll\(C'\fR
		1749	in the prepare watcher and would dispose of the check watcher.
		1750	.PP
		1751	Method 3: If the module to be embedded supports explicit event
		1752	notification (adns does), you can also make use of the actual watcher
		1753	callbacks, and only destroy/create the watchers in the prepare watcher.
		1754	.PP
		1755	.Vb 5
		1756	\& static void
		1757	\& timer_cb (EV_P_ ev_timer *w, int revents)
		1758	\& {
		1759	\& adns_state ads = (adns_state)w->data;
		1760	\& update_now (EV_A);
		1761	.Ve
		1762	.PP
		1763	.Vb 2
		1764	\& adns_processtimeouts (ads, &tv_now);
		1765	\& }
		1766	.Ve
		1767	.PP
		1768	.Vb 5
		1769	\& static void
		1770	\& io_cb (EV_P_ ev_io *w, int revents)
		1771	\& {
		1772	\& adns_state ads = (adns_state)w->data;
		1773	\& update_now (EV_A);
		1774	.Ve
		1775	.PP
		1776	.Vb 3
		1777	\& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
		1778	\& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
		1779	\& }
		1780	.Ve
		1781	.PP
		1782	.Vb 1
		1783	\& // do not ever call adns_afterpoll
		1784	.Ve
		1785	.PP
		1786	Method 4: Do not use a prepare or check watcher because the module you
		1787	want to embed is too inflexible to support it. Instead, youc na override
		1788	their poll function. The drawback with this solution is that the main
		1789	loop is now no longer controllable by \s-1EV\s0. The \f(CW\(C`Glib::EV\(C'\fR module does
		1790	this.
		1791	.PP
		1792	.Vb 4
		1793	\& static gint
		1794	\& event_poll_func (GPollFD *fds, guint nfds, gint timeout)
		1795	\& {
		1796	\& int got_events = 0;
		1797	.Ve
		1798	.PP
		1799	.Vb 2
		1800	\& for (n = 0; n < nfds; ++n)
		1801	\& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events
		1802	.Ve
		1803	.PP
		1804	.Vb 2
		1805	\& if (timeout >= 0)
		1806	\& // create/start timer
		1807	.Ve
		1808	.PP
		1809	.Vb 2
		1810	\& // poll
		1811	\& ev_loop (EV_A_ 0);
		1812	.Ve
		1813	.PP
		1814	.Vb 3
		1815	\& // stop timer again
		1816	\& if (timeout >= 0)
		1817	\& ev_timer_stop (EV_A_ &to);
		1818	.Ve
		1819	.PP
		1820	.Vb 3
		1821	\& // stop io watchers again - their callbacks should have set
		1822	\& for (n = 0; n < nfds; ++n)
		1823	\& ev_io_stop (EV_A_ iow [n]);
		1824	.Ve
		1825	.PP
		1826	.Vb 2
		1827	\& return got_events;
1360	\& }	1828	\& }
1361	.Ve	1829	.Ve
1362	.ie n .Sh """ev_embed"" \- when one backend isn't enough..."	1830	.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1363	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."	1831	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1364	.IX Subsection "ev_embed - when one backend isn't enough..."	1832	.IX Subsection "ev_embed - when one backend isn't enough..."
…		…
1449	.IP "ev_embed_sweep (loop, ev_embed *)" 4	1917	.IP "ev_embed_sweep (loop, ev_embed *)" 4
1450	.IX Item "ev_embed_sweep (loop, ev_embed *)"	1918	.IX Item "ev_embed_sweep (loop, ev_embed *)"
1451	Make a single, non-blocking sweep over the embedded loop. This works	1919	Make a single, non-blocking sweep over the embedded loop. This works
1452	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most	1920	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most
1453	apropriate way for embedded loops.	1921	apropriate way for embedded loops.
		1922	.IP "struct ev_loop *loop [read\-only]" 4
		1923	.IX Item "struct ev_loop *loop [read-only]"
		1924	The embedded event loop.
		1925	.ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork"
		1926	.el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
		1927	.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
		1928	Fork watchers are called when a \f(CW\(C`fork ()\(C'\fR was detected (usually because
		1929	whoever is a good citizen cared to tell libev about it by calling
		1930	\&\f(CW\(C`ev_default_fork\(C'\fR or \f(CW\(C`ev_loop_fork\(C'\fR). The invocation is done before the
		1931	event loop blocks next and before \f(CW\(C`ev_check\(C'\fR watchers are being called,
		1932	and only in the child after the fork. If whoever good citizen calling
		1933	\&\f(CW\(C`ev_default_fork\(C'\fR cheats and calls it in the wrong process, the fork
		1934	handlers will be invoked, too, of course.
		1935	.IP "ev_fork_init (ev_signal *, callback)" 4
		1936	.IX Item "ev_fork_init (ev_signal *, callback)"
		1937	Initialises and configures the fork watcher \- it has no parameters of any
		1938	kind. There is a \f(CW\(C`ev_fork_set\(C'\fR macro, but using it is utterly pointless,
		1939	believe me.
1454	.SH "OTHER FUNCTIONS"	1940	.SH "OTHER FUNCTIONS"
1455	.IX Header "OTHER FUNCTIONS"	1941	.IX Header "OTHER FUNCTIONS"
1456	There are some other functions of possible interest. Described. Here. Now.	1942	There are some other functions of possible interest. Described. Here. Now.
1457	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4	1943	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
1458	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"	1944	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
…		…
1530	.PP	2016	.PP
1531	.Vb 1	2017	.Vb 1
1532	\& #include <ev++.h>	2018	\& #include <ev++.h>
1533	.Ve	2019	.Ve
1534	.PP	2020	.PP
1535	(it is not installed by default). This automatically includes \fIev.h\fR	2021	This automatically includes \fIev.h\fR and puts all of its definitions (many
1536	and puts all of its definitions (many of them macros) into the global	2022	of them macros) into the global namespace. All \*(C+ specific things are
1537	namespace. All \(C+ specific things are put into the \f(CW\(C`ev\*(C'\fR namespace.	2023	put into the \f(CW\(C`ev\(C'\fR namespace. It should support all the same embedding
		2024	options as \fIev.h\fR, most notably \f(CW\(C`EV_MULTIPLICITY\(C'\fR.
1538	.PP	2025	.PP
1539	It should support all the same embedding options as \fIev.h\fR, most notably	2026	Care has been taken to keep the overhead low. The only data member the \*(C+
1540	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR.	2027	classes add (compared to plain C\-style watchers) is the event loop pointer
		2028	that the watcher is associated with (or no additional members at all if
		2029	you disable \f(CW\(C`EV_MULTIPLICITY\(C'\fR when embedding libev).
		2030	.PP
		2031	Currently, functions, and static and non-static member functions can be
		2032	used as callbacks. Other types should be easy to add as long as they only
		2033	need one additional pointer for context. If you need support for other
		2034	types of functors please contact the author (preferably after implementing
		2035	it).
1541	.PP	2036	.PP
1542	Here is a list of things available in the \f(CW\(C`ev\(C'\fR namespace:	2037	Here is a list of things available in the \f(CW\(C`ev\(C'\fR namespace:
1543	.ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4	2038	.ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4
1544	.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4	2039	.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4
1545	.IX Item "ev::READ, ev::WRITE etc."	2040	.IX Item "ev::READ, ev::WRITE etc."
…		…
1557	which is called \f(CW\(C`ev::sig\(C'\fR to avoid clashes with the \f(CW\(C`signal\(C'\fR macro	2052	which is called \f(CW\(C`ev::sig\(C'\fR to avoid clashes with the \f(CW\(C`signal\(C'\fR macro
1558	defines by many implementations.	2053	defines by many implementations.
1559	.Sp	2054	.Sp
1560	All of those classes have these methods:	2055	All of those classes have these methods:
1561	.RS 4	2056	.RS 4
1562	.IP "ev::TYPE::TYPE (object , object::method )" 4	2057	.IP "ev::TYPE::TYPE ()" 4
1563	.IX Item "ev::TYPE::TYPE (object , object::method )"	2058	.IX Item "ev::TYPE::TYPE ()"
1564	.PD 0	2059	.PD 0
1565	.IP "ev::TYPE::TYPE (object , object::method , struct ev_loop *)" 4	2060	.IP "ev::TYPE::TYPE (struct ev_loop *)" 4
1566	.IX Item "ev::TYPE::TYPE (object , object::method , struct ev_loop *)"	2061	.IX Item "ev::TYPE::TYPE (struct ev_loop *)"
1567	.IP "ev::TYPE::~TYPE" 4	2062	.IP "ev::TYPE::~TYPE" 4
1568	.IX Item "ev::TYPE::~TYPE"	2063	.IX Item "ev::TYPE::~TYPE"
1569	.PD	2064	.PD
1570	The constructor takes a pointer to an object and a method pointer to	2065	The constructor (optionally) takes an event loop to associate the watcher
1571	the event handler callback to call in this class. The constructor calls	2066	with. If it is omitted, it will use \f(CW\(C`EV_DEFAULT\(C'\fR.
1572	\&\f(CW\(C`ev_init\(C'\fR for you, which means you have to call the \f(CW\(C`set\(C'\fR method	2067	.Sp
1573	before starting it. If you do not specify a loop then the constructor	2068	The constructor calls \f(CW\(C`ev_init\(C'\fR for you, which means you have to call the
1574	automatically associates the default loop with this watcher.	2069	\&\f(CW\(C`set\(C'\fR method before starting it.
		2070	.Sp
		2071	It will not set a callback, however: You have to call the templated \f(CW\(C`set\(C'\fR
		2072	method to set a callback before you can start the watcher.
		2073	.Sp
		2074	(The reason why you have to use a method is a limitation in \*(C+ which does
		2075	not allow explicit template arguments for constructors).
1575	.Sp	2076	.Sp
1576	The destructor automatically stops the watcher if it is active.	2077	The destructor automatically stops the watcher if it is active.
		2078	.IP "w\->set<class, &class::method> (object *)" 4
		2079	.IX Item "w->set<class, &class::method> (object *)"
		2080	This method sets the callback method to call. The method has to have a
		2081	signature of \f(CW\(C`void ()(ev_TYPE &, int)\*(C'\fR, it receives the watcher as
		2082	first argument and the \f(CW\(C`revents\(C'\fR as second. The object must be given as
		2083	parameter and is stored in the \f(CW\(C`data\(C'\fR member of the watcher.
		2084	.Sp
		2085	This method synthesizes efficient thunking code to call your method from
		2086	the C callback that libev requires. If your compiler can inline your
		2087	callback (i.e. it is visible to it at the place of the \f(CW\(C`set\(C'\fR call and
		2088	your compiler is good :), then the method will be fully inlined into the
		2089	thunking function, making it as fast as a direct C callback.
		2090	.Sp
		2091	Example: simple class declaration and watcher initialisation
		2092	.Sp
		2093	.Vb 4
		2094	\& struct myclass
		2095	\& {
		2096	\& void io_cb (ev::io &w, int revents) { }
		2097	\& }
		2098	.Ve
		2099	.Sp
		2100	.Vb 3
		2101	\& myclass obj;
		2102	\& ev::io iow;
		2103	\& iow.set <myclass, &myclass::io_cb> (&obj);
		2104	.Ve
		2105	.IP "w\->set<function> (void *data = 0)" 4
		2106	.IX Item "w->set<function> (void *data = 0)"
		2107	Also sets a callback, but uses a static method or plain function as
		2108	callback. The optional \f(CW\(C`data\(C'\fR argument will be stored in the watcher's
		2109	\&\f(CW\(C`data\(C'\fR member and is free for you to use.
		2110	.Sp
		2111	The prototype of the \f(CW\(C`function\(C'\fR must be \f(CW\(C`void ()(ev::TYPE &w, int)\*(C'\fR.
		2112	.Sp
		2113	See the method\-\f(CW\(C`set\(C'\fR above for more details.
		2114	.Sp
		2115	Example:
		2116	.Sp
		2117	.Vb 2
		2118	\& static void io_cb (ev::io &w, int revents) { }
		2119	\& iow.set <io_cb> ();
		2120	.Ve
1577	.IP "w\->set (struct ev_loop *)" 4	2121	.IP "w\->set (struct ev_loop *)" 4
1578	.IX Item "w->set (struct ev_loop *)"	2122	.IX Item "w->set (struct ev_loop *)"
1579	Associates a different \f(CW\(C`struct ev_loop\(C'\fR with this watcher. You can only	2123	Associates a different \f(CW\(C`struct ev_loop\(C'\fR with this watcher. You can only
1580	do this when the watcher is inactive (and not pending either).	2124	do this when the watcher is inactive (and not pending either).
1581	.IP "w\->set ([args])" 4	2125	.IP "w\->set ([args])" 4
1582	.IX Item "w->set ([args])"	2126	.IX Item "w->set ([args])"
1583	Basically the same as \f(CW\(C`ev_TYPE_set\(C'\fR, with the same args. Must be	2127	Basically the same as \f(CW\(C`ev_TYPE_set\(C'\fR, with the same args. Must be
1584	called at least once. Unlike the C counterpart, an active watcher gets	2128	called at least once. Unlike the C counterpart, an active watcher gets
1585	automatically stopped and restarted.	2129	automatically stopped and restarted when reconfiguring it with this
		2130	method.
1586	.IP "w\->start ()" 4	2131	.IP "w\->start ()" 4
1587	.IX Item "w->start ()"	2132	.IX Item "w->start ()"
1588	Starts the watcher. Note that there is no \f(CW\(C`loop\(C'\fR argument as the	2133	Starts the watcher. Note that there is no \f(CW\(C`loop\(C'\fR argument, as the
1589	constructor already takes the loop.	2134	constructor already stores the event loop.
1590	.IP "w\->stop ()" 4	2135	.IP "w\->stop ()" 4
1591	.IX Item "w->stop ()"	2136	.IX Item "w->stop ()"
1592	Stops the watcher if it is active. Again, no \f(CW\(C`loop\(C'\fR argument.	2137	Stops the watcher if it is active. Again, no \f(CW\(C`loop\(C'\fR argument.
1593	.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4	2138	.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4
1594	.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4	2139	.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4
…		…
1597	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.	2142	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.
1598	.ie n .IP "w\->sweep () ""ev::embed"" only" 4	2143	.ie n .IP "w\->sweep () ""ev::embed"" only" 4
1599	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4	2144	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
1600	.IX Item "w->sweep () ev::embed only"	2145	.IX Item "w->sweep () ev::embed only"
1601	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.	2146	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.
		2147	.ie n .IP "w\->update () ""ev::stat"" only" 4
		2148	.el .IP "w\->update () \f(CWev::stat\fR only" 4
		2149	.IX Item "w->update () ev::stat only"
		2150	Invokes \f(CW\(C`ev_stat_stat\(C'\fR.
1602	.RE	2151	.RE
1603	.RS 4	2152	.RS 4
1604	.RE	2153	.RE
1605	.PP	2154	.PP
1606	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in	2155	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
…		…
1616	.Vb 2	2165	.Vb 2
1617	\& myclass ();	2166	\& myclass ();
1618	\& }	2167	\& }
1619	.Ve	2168	.Ve
1620	.PP	2169	.PP
1621	.Vb 6	2170	.Vb 4
1622	\& myclass::myclass (int fd)	2171	\& myclass::myclass (int fd)
1623	\& : io (this, &myclass::io_cb),
1624	\& idle (this, &myclass::idle_cb)
1625	\& {	2172	\& {
		2173	\& io .set <myclass, &myclass::io_cb > (this);
		2174	\& idle.set <myclass, &myclass::idle_cb> (this);
		2175	.Ve
		2176	.PP
		2177	.Vb 2
1626	\& io.start (fd, ev::READ);	2178	\& io.start (fd, ev::READ);
1627	\& }	2179	\& }
		2180	.Ve
		2181	.SH "MACRO MAGIC"
		2182	.IX Header "MACRO MAGIC"
		2183	Libev can be compiled with a variety of options, the most fundemantal is
		2184	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR. This option determines whether (most) functions and
		2185	callbacks have an initial \f(CW\(C`struct ev_loop \*(C'\fR argument.
		2186	.PP
		2187	To make it easier to write programs that cope with either variant, the
		2188	following macros are defined:
		2189	.ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4
		2190	.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
		2191	.IX Item "EV_A, EV_A_"
		2192	This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
		2193	loop argument\(R"). The \f(CW\(C`EV_A\*(C'\fR form is used when this is the sole argument,
		2194	\&\f(CW\(C`EV_A_\(C'\fR is used when other arguments are following. Example:
		2195	.Sp
		2196	.Vb 3
		2197	\& ev_unref (EV_A);
		2198	\& ev_timer_add (EV_A_ watcher);
		2199	\& ev_loop (EV_A_ 0);
		2200	.Ve
		2201	.Sp
		2202	It assumes the variable \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR is in scope,
		2203	which is often provided by the following macro.
		2204	.ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4
		2205	.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
		2206	.IX Item "EV_P, EV_P_"
		2207	This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
		2208	loop parameter\(R"). The \f(CW\(C`EV_P\*(C'\fR form is used when this is the sole parameter,
		2209	\&\f(CW\(C`EV_P_\(C'\fR is used when other parameters are following. Example:
		2210	.Sp
		2211	.Vb 2
		2212	\& // this is how ev_unref is being declared
		2213	\& static void ev_unref (EV_P);
		2214	.Ve
		2215	.Sp
		2216	.Vb 2
		2217	\& // this is how you can declare your typical callback
		2218	\& static void cb (EV_P_ ev_timer *w, int revents)
		2219	.Ve
		2220	.Sp
		2221	It declares a parameter \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR, quite
		2222	suitable for use with \f(CW\(C`EV_A\(C'\fR.
		2223	.ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4
		2224	.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
		2225	.IX Item "EV_DEFAULT, EV_DEFAULT_"
		2226	Similar to the other two macros, this gives you the value of the default
		2227	loop, if multiple loops are supported (\(L"ev loop default\(R").
		2228	.PP
		2229	Example: Declare and initialise a check watcher, utilising the above
		2230	macros so it will work regardless of whether multiple loops are supported
		2231	or not.
		2232	.PP
		2233	.Vb 5
		2234	\& static void
		2235	\& check_cb (EV_P_ ev_timer *w, int revents)
		2236	\& {
		2237	\& ev_check_stop (EV_A_ w);
		2238	\& }
		2239	.Ve
		2240	.PP
		2241	.Vb 4
		2242	\& ev_check check;
		2243	\& ev_check_init (&check, check_cb);
		2244	\& ev_check_start (EV_DEFAULT_ &check);
		2245	\& ev_loop (EV_DEFAULT_ 0);
1628	.Ve	2246	.Ve
1629	.SH "EMBEDDING"	2247	.SH "EMBEDDING"
1630	.IX Header "EMBEDDING"	2248	.IX Header "EMBEDDING"
1631	Libev can (and often is) directly embedded into host	2249	Libev can (and often is) directly embedded into host
1632	applications. Examples of applications that embed it include the Deliantra	2250	applications. Examples of applications that embed it include the Deliantra
…		…
1681	.Vb 1	2299	.Vb 1
1682	\& ev_win32.c required on win32 platforms only	2300	\& ev_win32.c required on win32 platforms only
1683	.Ve	2301	.Ve
1684	.PP	2302	.PP
1685	.Vb 5	2303	.Vb 5
1686	\& ev_select.c only when select backend is enabled (which is by default)	2304	\& ev_select.c only when select backend is enabled (which is enabled by default)
1687	\& ev_poll.c only when poll backend is enabled (disabled by default)	2305	\& ev_poll.c only when poll backend is enabled (disabled by default)
1688	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)	2306	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
1689	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	2307	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1690	\& ev_port.c only when the solaris port backend is enabled (disabled by default)	2308	\& ev_port.c only when the solaris port backend is enabled (disabled by default)
1691	.Ve	2309	.Ve
…		…
1812	otherwise another method will be used as fallback. This is the preferred	2430	otherwise another method will be used as fallback. This is the preferred
1813	backend for Solaris 10 systems.	2431	backend for Solaris 10 systems.
1814	.IP "\s-1EV_USE_DEVPOLL\s0" 4	2432	.IP "\s-1EV_USE_DEVPOLL\s0" 4
1815	.IX Item "EV_USE_DEVPOLL"	2433	.IX Item "EV_USE_DEVPOLL"
1816	reserved for future expansion, works like the \s-1USE\s0 symbols above.	2434	reserved for future expansion, works like the \s-1USE\s0 symbols above.
		2435	.IP "\s-1EV_USE_INOTIFY\s0" 4
		2436	.IX Item "EV_USE_INOTIFY"
		2437	If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify
		2438	interface to speed up \f(CW\(C`ev_stat\(C'\fR watchers. Its actual availability will
		2439	be detected at runtime.
1817	.IP "\s-1EV_H\s0" 4	2440	.IP "\s-1EV_H\s0" 4
1818	.IX Item "EV_H"	2441	.IX Item "EV_H"
1819	The name of the \fIev.h\fR header file used to include it. The default if	2442	The name of the \fIev.h\fR header file used to include it. The default if
1820	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This	2443	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
1821	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.	2444	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
…		…
1839	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions	2462	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
1840	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create	2463	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create
1841	additional independent event loops. Otherwise there will be no support	2464	additional independent event loops. Otherwise there will be no support
1842	for multiple event loops and there is no first event loop pointer	2465	for multiple event loops and there is no first event loop pointer
1843	argument. Instead, all functions act on the single default loop.	2466	argument. Instead, all functions act on the single default loop.
		2467	.IP "\s-1EV_MINPRI\s0" 4
		2468	.IX Item "EV_MINPRI"
		2469	.PD 0
		2470	.IP "\s-1EV_MAXPRI\s0" 4
		2471	.IX Item "EV_MAXPRI"
		2472	.PD
		2473	The range of allowed priorities. \f(CW\(C`EV_MINPRI\(C'\fR must be smaller or equal to
		2474	\&\f(CW\(C`EV_MAXPRI\(C'\fR, but otherwise there are no non-obvious limitations. You can
		2475	provide for more priorities by overriding those symbols (usually defined
		2476	to be \f(CW\(C`\-2\(C'\fR and \f(CW2\fR, respectively).
		2477	.Sp
		2478	When doing priority-based operations, libev usually has to linearly search
		2479	all the priorities, so having many of them (hundreds) uses a lot of space
		2480	and time, so using the defaults of five priorities (\-2 .. +2) is usually
		2481	fine.
		2482	.Sp
		2483	If your embedding app does not need any priorities, defining these both to
		2484	\&\f(CW0\fR will save some memory and cpu.
1844	.IP "\s-1EV_PERIODICS\s0" 4	2485	.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
1845	.IX Item "EV_PERIODICS"	2486	.IX Item "EV_PERIODIC_ENABLE"
1846	If undefined or defined to be \f(CW1\fR, then periodic timers are supported,	2487	If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
1847	otherwise not. This saves a few kb of code.	2488	defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
		2489	code.
		2490	.IP "\s-1EV_IDLE_ENABLE\s0" 4
		2491	.IX Item "EV_IDLE_ENABLE"
		2492	If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If
		2493	defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
		2494	code.
		2495	.IP "\s-1EV_EMBED_ENABLE\s0" 4
		2496	.IX Item "EV_EMBED_ENABLE"
		2497	If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
		2498	defined to be \f(CW0\fR, then they are not.
		2499	.IP "\s-1EV_STAT_ENABLE\s0" 4
		2500	.IX Item "EV_STAT_ENABLE"
		2501	If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
		2502	defined to be \f(CW0\fR, then they are not.
		2503	.IP "\s-1EV_FORK_ENABLE\s0" 4
		2504	.IX Item "EV_FORK_ENABLE"
		2505	If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If
		2506	defined to be \f(CW0\fR, then they are not.
		2507	.IP "\s-1EV_MINIMAL\s0" 4
		2508	.IX Item "EV_MINIMAL"
		2509	If you need to shave off some kilobytes of code at the expense of some
		2510	speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
		2511	some inlining decisions, saves roughly 30% codesize of amd64.
		2512	.IP "\s-1EV_PID_HASHSIZE\s0" 4
		2513	.IX Item "EV_PID_HASHSIZE"
		2514	\&\f(CW\(C`ev_child\(C'\fR watchers use a small hash table to distribute workload by
		2515	pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\(C`EV_MINIMAL\(C'\fR), usually more
		2516	than enough. If you need to manage thousands of children you might want to
		2517	increase this value (\fImust\fR be a power of two).
		2518	.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
		2519	.IX Item "EV_INOTIFY_HASHSIZE"
		2520	\&\f(CW\(C`ev_staz\(C'\fR watchers use a small hash table to distribute workload by
		2521	inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\(C`EV_MINIMAL\(C'\fR),
		2522	usually more than enough. If you need to manage thousands of \f(CW\(C`ev_stat\(C'\fR
		2523	watchers you might want to increase this value (\fImust\fR be a power of
		2524	two).
1848	.IP "\s-1EV_COMMON\s0" 4	2525	.IP "\s-1EV_COMMON\s0" 4
1849	.IX Item "EV_COMMON"	2526	.IX Item "EV_COMMON"
1850	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining	2527	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining
1851	this macro to a something else you can include more and other types of	2528	this macro to a something else you can include more and other types of
1852	members. You have to define it each time you include one of the files,	2529	members. You have to define it each time you include one of the files,
…		…
1882	interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file	2559	interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
1883	will be compiled. It is pretty complex because it provides its own header	2560	will be compiled. It is pretty complex because it provides its own header
1884	file.	2561	file.
1885	.Sp	2562	.Sp
1886	The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file	2563	The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
1887	that everybody includes and which overrides some autoconf choices:	2564	that everybody includes and which overrides some configure choices:
1888	.Sp	2565	.Sp
1889	.Vb 4	2566	.Vb 9
		2567	\& #define EV_MINIMAL 1
1890	\& #define EV_USE_POLL 0	2568	\& #define EV_USE_POLL 0
1891	\& #define EV_MULTIPLICITY 0	2569	\& #define EV_MULTIPLICITY 0
1892	\& #define EV_PERIODICS 0	2570	\& #define EV_PERIODIC_ENABLE 0
		2571	\& #define EV_STAT_ENABLE 0
		2572	\& #define EV_FORK_ENABLE 0
1893	\& #define EV_CONFIG_H <config.h>	2573	\& #define EV_CONFIG_H <config.h>
		2574	\& #define EV_MINPRI 0
		2575	\& #define EV_MAXPRI 0
1894	.Ve	2576	.Ve
1895	.Sp	2577	.Sp
1896	.Vb 1	2578	.Vb 1
1897	\& #include "ev++.h"	2579	\& #include "ev++.h"
1898	.Ve	2580	.Ve
…		…
1906	.SH "COMPLEXITIES"	2588	.SH "COMPLEXITIES"
1907	.IX Header "COMPLEXITIES"	2589	.IX Header "COMPLEXITIES"
1908	In this section the complexities of (many of) the algorithms used inside	2590	In this section the complexities of (many of) the algorithms used inside
1909	libev will be explained. For complexity discussions about backends see the	2591	libev will be explained. For complexity discussions about backends see the
1910	documentation for \f(CW\(C`ev_default_init\(C'\fR.	2592	documentation for \f(CW\(C`ev_default_init\(C'\fR.
		2593	.Sp
		2594	All of the following are about amortised time: If an array needs to be
		2595	extended, libev needs to realloc and move the whole array, but this
		2596	happens asymptotically never with higher number of elements, so O(1) might
		2597	mean it might do a lengthy realloc operation in rare cases, but on average
		2598	it is much faster and asymptotically approaches constant time.
1911	.RS 4	2599	.RS 4
1912	.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4	2600	.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
1913	.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"	2601	.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
1914	.PD 0	2602	This means that, when you have a watcher that triggers in one hour and
		2603	there are 100 watchers that would trigger before that then inserting will
		2604	have to skip those 100 watchers.
1915	.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4	2605	.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4
1916	.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"	2606	.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
		2607	That means that for changing a timer costs less than removing/adding them
		2608	as only the relative motion in the event queue has to be paid for.
1917	.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4	2609	.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
1918	.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"	2610	.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
1919	.IP "Stopping check/prepare/idle watchers: O(1)" 4	2611	These just add the watcher into an array or at the head of a list.
1920	.IX Item "Stopping check/prepare/idle watchers: O(1)"	2612	=item Stopping check/prepare/idle watchers: O(1)
1921	.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4	2613	.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
1922	.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))"	2614	.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"
		2615	These watchers are stored in lists then need to be walked to find the
		2616	correct watcher to remove. The lists are usually short (you don't usually
		2617	have many watchers waiting for the same fd or signal).
1923	.IP "Finding the next timer per loop iteration: O(1)" 4	2618	.IP "Finding the next timer per loop iteration: O(1)" 4
1924	.IX Item "Finding the next timer per loop iteration: O(1)"	2619	.IX Item "Finding the next timer per loop iteration: O(1)"
		2620	.PD 0
1925	.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4	2621	.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
1926	.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"	2622	.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
		2623	.PD
		2624	A change means an I/O watcher gets started or stopped, which requires
		2625	libev to recalculate its status (and possibly tell the kernel).
1927	.IP "Activating one watcher: O(1)" 4	2626	.IP "Activating one watcher: O(1)" 4
1928	.IX Item "Activating one watcher: O(1)"	2627	.IX Item "Activating one watcher: O(1)"
		2628	.PD 0
		2629	.IP "Priority handling: O(number_of_priorities)" 4
		2630	.IX Item "Priority handling: O(number_of_priorities)"
		2631	.PD
		2632	Priorities are implemented by allocating some space for each
		2633	priority. When doing priority-based operations, libev usually has to
		2634	linearly search all the priorities.
1929	.RE	2635	.RE
1930	.RS 4	2636	.RS 4
1931	.PD
1932	.SH "AUTHOR"	2637	.SH "AUTHOR"
1933	.IX Header "AUTHOR"	2638	.IX Header "AUTHOR"
1934	Marc Lehmann <libev@schmorp.de>.	2639	Marc Lehmann <libev@schmorp.de>.

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Revision 1.21 by root, Mon Nov 26 10:20:42 2007 UTC vs.
Revision 1.45 by root, Sat Dec 8 22:11:14 2007 UTC