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

Comparing libev/ev.3 (file contents):
Revision 1.17 by root, Sat Nov 24 16:31:45 2007 UTC vs.
Revision 1.37 by root, Fri Dec 7 16:49:49 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 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation"	132	.TH "<STANDARD INPUT>" 1 "2007-12-07" "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"
142	Libev is an event loop: you register interest in certain events (such as a	201	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	202	file descriptor being readable or a timeout occuring), and it will manage
144	these event sources and provide your program with events.	203	these event sources and provide your program with events.
…		…
151	watchers\fR, which are relatively small C structures you initialise with the	210	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	211	details of the event, and then hand it over to libev by \fIstarting\fR the
153	watcher.	212	watcher.
154	.SH "FEATURES"	213	.SH "FEATURES"
155	.IX Header "FEATURES"	214	.IX Header "FEATURES"
156	Libev supports select, poll, the linux-specific epoll and the bsd-specific	215	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	216	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	217	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	218	(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	219	with customised rescheduling (\f(CW\(C`ev_periodic\(C'\fR), synchronous signals
161	fast (see this benchmark comparing	220	(\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).	221	watchers dealing with the event loop mechanism itself (\f(CW\(C`ev_idle\(C'\fR,
		222	\&\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
		223	file watchers (\f(CW\(C`ev_stat\(C'\fR) and even limited support for fork events
		224	(\f(CW\(C`ev_fork\(C'\fR).
		225	.PP
		226	It also is quite fast (see this
		227	benchmark comparing it to libevent
		228	for example).
163	.SH "CONVENTIONS"	229	.SH "CONVENTIONS"
164	.IX Header "CONVENTIONS"	230	.IX Header "CONVENTIONS"
165	Libev is very configurable. In this manual the default configuration	231	Libev is very configurable. In this manual the default configuration will
166	will be described, which supports multiple event loops. For more info	232	be described, which supports multiple event loops. For more info about
167	about various configuration options please have a look at the file	233	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	234	this manual. If libev was configured without support for multiple event
169	support for multiple event loops, then all functions taking an initial	235	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)	236	(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"	237	.SH "TIME REPRESENTATION"
173	.IX Header "TIME REPRESENTATION"	238	.IX Header "TIME REPRESENTATION"
174	Libev represents time as a single floating point number, representing the	239	Libev represents time as a single floating point number, representing the
175	(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near	240	(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	241	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,	266	Usually, it's a good idea to terminate if the major versions mismatch,
202	as this indicates an incompatible change. Minor versions are usually	267	as this indicates an incompatible change. Minor versions are usually
203	compatible to older versions, so a larger minor version alone is usually	268	compatible to older versions, so a larger minor version alone is usually
204	not a problem.	269	not a problem.
205	.Sp	270	.Sp
206	Example: make sure we haven't accidentally been linked against the wrong	271	Example: Make sure we haven't accidentally been linked against the wrong
207	version:	272	version.
208	.Sp	273	.Sp
209	.Vb 3	274	.Vb 3
210	\& assert (("libev version mismatch",	275	\& assert (("libev version mismatch",
211	\& ev_version_major () == EV_VERSION_MAJOR	276	\& ev_version_major () == EV_VERSION_MAJOR
212	\& && ev_version_minor () >= EV_VERSION_MINOR));	277	\& && ev_version_minor () >= EV_VERSION_MINOR));
…		…
242	recommended ones.	307	recommended ones.
243	.Sp	308	.Sp
244	See the description of \f(CW\(C`ev_embed\(C'\fR watchers for more info.	309	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	310	.IP "ev_set_allocator (void (cb)(void *ptr, long size))" 4
246	.IX Item "ev_set_allocator (void (cb)(void *ptr, long size))"	311	.IX Item "ev_set_allocator (void (cb)(void *ptr, long size))"
247	Sets the allocation function to use (the prototype is similar to the	312	Sets the allocation function to use (the prototype is similar \- the
248	realloc C function, the semantics are identical). It is used to allocate	313	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	314	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	315	memory needs to be allocated, the library might abort or take some
251	destructive action. The default is your system realloc function.	316	potentially destructive action. The default is your system realloc
		317	function.
252	.Sp	318	.Sp
253	You could override this function in high-availability programs to, say,	319	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,	320	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.	321	or even to sleep a while and retry until some memory is available.
256	.Sp	322	.Sp
257	Example: replace the libev allocator with one that waits a bit and then	323	Example: Replace the libev allocator with one that waits a bit and then
258	retries: better than mine).	324	retries).
259	.Sp	325	.Sp
260	.Vb 6	326	.Vb 6
261	\& static void *	327	\& static void *
262	\& persistent_realloc (void *ptr, long size)	328	\& persistent_realloc (void *ptr, size_t size)
263	\& {	329	\& {
264	\& for (;;)	330	\& for (;;)
265	\& {	331	\& {
266	\& void *newptr = realloc (ptr, size);	332	\& void *newptr = realloc (ptr, size);
267	.Ve	333	.Ve
…		…
289	callback is set, then libev will expect it to remedy the sitution, no	355	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	356	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	357	requested operation, or, if the condition doesn't go away, do bad stuff
292	(such as abort).	358	(such as abort).
293	.Sp	359	.Sp
294	Example: do the same thing as libev does internally:	360	Example: This is basically the same thing that libev does internally, too.
295	.Sp	361	.Sp
296	.Vb 6	362	.Vb 6
297	\& static void	363	\& static void
298	\& fatal_error (const char *msg)	364	\& fatal_error (const char *msg)
299	\& {	365	\& {
…		…
345	or setgid) then libev will \fInot\fR look at the environment variable	411	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	412	\&\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	413	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	414	useful to try out specific backends to test their performance, or to work
349	around bugs.	415	around bugs.
		416	.ie n .IP """EVFLAG_FORKCHECK""" 4
		417	.el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4
		418	.IX Item "EVFLAG_FORKCHECK"
		419	Instead of calling \f(CW\(C`ev_default_fork\(C'\fR or \f(CW\(C`ev_loop_fork\(C'\fR manually after
		420	a fork, you can also make libev check for a fork in each iteration by
		421	enabling this flag.
		422	.Sp
		423	This works by calling \f(CW\(C`getpid ()\(C'\fR on every iteration of the loop,
		424	and thus this might slow down your event loop if you do a lot of loop
		425	iterations and little real work, but is usually not noticeable (on my
		426	Linux system for example, \f(CW\(C`getpid\(C'\fR is actually a simple 5\-insn sequence
		427	without a syscall and thus \fIvery\fR fast, but my Linux system also has
		428	\&\f(CW\(C`pthread_atfork\(C'\fR which is even faster).
		429	.Sp
		430	The big advantage of this flag is that you can forget about fork (and
		431	forget about forgetting to tell libev about forking) when you use this
		432	flag.
		433	.Sp
		434	This flag setting cannot be overriden or specified in the \f(CW\(C`LIBEV_FLAGS\(C'\fR
		435	environment variable.
350	.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4	436	.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4
351	.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4	437	.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4
352	.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"	438	.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"
353	This is your standard \fIselect\fR\\|(2) backend. Not \fIcompletely\fR standard, as	439	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,	440	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	534	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	535	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	536	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).	537	undefined behaviour (or a failed assertion if assertions are enabled).
452	.Sp	538	.Sp
453	Example: try to create a event loop that uses epoll and nothing else.	539	Example: Try to create a event loop that uses epoll and nothing else.
454	.Sp	540	.Sp
455	.Vb 3	541	.Vb 3
456	\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	542	\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
457	\& if (!epoller)	543	\& if (!epoller)
458	\& fatal ("no epoll found here, maybe it hides under your chair");	544	\& fatal ("no epoll found here, maybe it hides under your chair");
…		…
495	.IP "ev_loop_fork (loop)" 4	581	.IP "ev_loop_fork (loop)" 4
496	.IX Item "ev_loop_fork (loop)"	582	.IX Item "ev_loop_fork (loop)"
497	Like \f(CW\(C`ev_default_fork\(C'\fR, but acts on an event loop created by	583	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	584	\&\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.	585	after fork, and how you do this is entirely your own problem.
		586	.IP "unsigned int ev_loop_count (loop)" 4
		587	.IX Item "unsigned int ev_loop_count (loop)"
		588	Returns the count of loop iterations for the loop, which is identical to
		589	the number of times libev did poll for new events. It starts at \f(CW0\fR and
		590	happily wraps around with enough iterations.
		591	.Sp
		592	This value can sometimes be useful as a generation counter of sorts (it
		593	\&\(L"ticks\(R" the number of loop iterations), as it roughly corresponds with
		594	\&\f(CW\(C`ev_prepare\(C'\fR and \f(CW\(C`ev_check\(C'\fR calls.
500	.IP "unsigned int ev_backend (loop)" 4	595	.IP "unsigned int ev_backend (loop)" 4
501	.IX Item "unsigned int ev_backend (loop)"	596	.IX Item "unsigned int ev_backend (loop)"
502	Returns one of the \f(CW\(C`EVBACKEND_\*(C'\fR flags indicating the event backend in	597	Returns one of the \f(CW\(C`EVBACKEND_\*(C'\fR flags indicating the event backend in
503	use.	598	use.
504	.IP "ev_tstamp ev_now (loop)" 4	599	.IP "ev_tstamp ev_now (loop)" 4
…		…
556	\& be handled here by queueing them when their watcher gets executed.	651	\& be handled here by queueing them when their watcher gets executed.
557	\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	652	\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
558	\& were used, return, otherwise continue with step *.	653	\& were used, return, otherwise continue with step *.
559	.Ve	654	.Ve
560	.Sp	655	.Sp
561	Example: queue some jobs and then loop until no events are outsanding	656	Example: Queue some jobs and then loop until no events are outsanding
562	anymore.	657	anymore.
563	.Sp	658	.Sp
564	.Vb 4	659	.Vb 4
565	\& ... queue jobs here, make sure they register event watchers as long	660	\& ... 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..)	661	\& ... 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	683	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	684	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	685	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.	686	libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.
592	.Sp	687	.Sp
593	Example: create a signal watcher, but keep it from keeping \f(CW\(C`ev_loop\(C'\fR	688	Example: Create a signal watcher, but keep it from keeping \f(CW\(C`ev_loop\(C'\fR
594	running when nothing else is active.	689	running when nothing else is active.
595	.Sp	690	.Sp
596	.Vb 4	691	.Vb 4
597	\& struct dv_signal exitsig;	692	\& struct ev_signal exitsig;
598	\& ev_signal_init (&exitsig, sig_cb, SIGINT);	693	\& ev_signal_init (&exitsig, sig_cb, SIGINT);
599	\& ev_signal_start (myloop, &exitsig);	694	\& ev_signal_start (loop, &exitsig);
600	\& evf_unref (myloop);	695	\& evf_unref (loop);
601	.Ve	696	.Ve
602	.Sp	697	.Sp
603	Example: for some weird reason, unregister the above signal handler again.	698	Example: For some weird reason, unregister the above signal handler again.
604	.Sp	699	.Sp
605	.Vb 2	700	.Vb 2
606	\& ev_ref (myloop);	701	\& ev_ref (loop);
607	\& ev_signal_stop (myloop, &exitsig);	702	\& ev_signal_stop (loop, &exitsig);
608	.Ve	703	.Ve
609	.SH "ANATOMY OF A WATCHER"	704	.SH "ANATOMY OF A WATCHER"
610	.IX Header "ANATOMY OF A WATCHER"	705	.IX Header "ANATOMY OF A WATCHER"
611	A watcher is a structure that you create and register to record your	706	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	707	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.	779	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	780	.ie n .IP """EV_CHILD""" 4
686	.el .IP "\f(CWEV_CHILD\fR" 4	781	.el .IP "\f(CWEV_CHILD\fR" 4
687	.IX Item "EV_CHILD"	782	.IX Item "EV_CHILD"
688	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.	783	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.
		784	.ie n .IP """EV_STAT""" 4
		785	.el .IP "\f(CWEV_STAT\fR" 4
		786	.IX Item "EV_STAT"
		787	The path specified in the \f(CW\(C`ev_stat\(C'\fR watcher changed its attributes somehow.
689	.ie n .IP """EV_IDLE""" 4	788	.ie n .IP """EV_IDLE""" 4
690	.el .IP "\f(CWEV_IDLE\fR" 4	789	.el .IP "\f(CWEV_IDLE\fR" 4
691	.IX Item "EV_IDLE"	790	.IX Item "EV_IDLE"
692	The \f(CW\(C`ev_idle\(C'\fR watcher has determined that you have nothing better to do.	791	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	792	.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	802	\&\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	803	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	804	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	805	(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).	806	\&\f(CW\(C`ev_loop\(C'\fR from blocking).
		807	.ie n .IP """EV_EMBED""" 4
		808	.el .IP "\f(CWEV_EMBED\fR" 4
		809	.IX Item "EV_EMBED"
		810	The embedded event loop specified in the \f(CW\(C`ev_embed\(C'\fR watcher needs attention.
		811	.ie n .IP """EV_FORK""" 4
		812	.el .IP "\f(CWEV_FORK\fR" 4
		813	.IX Item "EV_FORK"
		814	The event loop has been resumed in the child process after fork (see
		815	\&\f(CW\(C`ev_fork\(C'\fR).
708	.ie n .IP """EV_ERROR""" 4	816	.ie n .IP """EV_ERROR""" 4
709	.el .IP "\f(CWEV_ERROR\fR" 4	817	.el .IP "\f(CWEV_ERROR\fR" 4
710	.IX Item "EV_ERROR"	818	.IX Item "EV_ERROR"
711	An unspecified error has occured, the watcher has been stopped. This might	819	An unspecified error has occured, the watcher has been stopped. This might
712	happen because the watcher could not be properly started because libev	820	happen because the watcher could not be properly started because libev
…		…
779	Returns a true value iff the watcher is pending, (i.e. it has outstanding	887	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	888	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	889	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	890	\&\f(CW\(C`ev_TYPE_set\(C'\fR is safe) and you must make sure the watcher is available to
783	libev (e.g. you cnanot \f(CW\(C`free ()\(C'\fR it).	891	libev (e.g. you cnanot \f(CW\(C`free ()\(C'\fR it).
784	.IP "callback = ev_cb (ev_TYPE *watcher)" 4	892	.IP "callback ev_cb (ev_TYPE *watcher)" 4
785	.IX Item "callback = ev_cb (ev_TYPE *watcher)"	893	.IX Item "callback ev_cb (ev_TYPE *watcher)"
786	Returns the callback currently set on the watcher.	894	Returns the callback currently set on the watcher.
787	.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4	895	.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
788	.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"	896	.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
789	Change the callback. You can change the callback at virtually any time	897	Change the callback. You can change the callback at virtually any time
790	(modulo threads).	898	(modulo threads).
		899	.IP "ev_set_priority (ev_TYPE *watcher, priority)" 4
		900	.IX Item "ev_set_priority (ev_TYPE *watcher, priority)"
		901	.PD 0
		902	.IP "int ev_priority (ev_TYPE *watcher)" 4
		903	.IX Item "int ev_priority (ev_TYPE *watcher)"
		904	.PD
		905	Set and query the priority of the watcher. The priority is a small
		906	integer between \f(CW\(C`EV_MAXPRI\(C'\fR (default: \f(CW2\fR) and \f(CW\(C`EV_MINPRI\(C'\fR
		907	(default: \f(CW\(C`\-2\(C'\fR). Pending watchers with higher priority will be invoked
		908	before watchers with lower priority, but priority will not keep watchers
		909	from being executed (except for \f(CW\(C`ev_idle\(C'\fR watchers).
		910	.Sp
		911	This means that priorities are \fIonly\fR used for ordering callback
		912	invocation after new events have been received. This is useful, for
		913	example, to reduce latency after idling, or more often, to bind two
		914	watchers on the same event and make sure one is called first.
		915	.Sp
		916	If you need to suppress invocation when higher priority events are pending
		917	you need to look at \f(CW\(C`ev_idle\(C'\fR watchers, which provide this functionality.
		918	.Sp
		919	The default priority used by watchers when no priority has been set is
		920	always \f(CW0\fR, which is supposed to not be too high and not be too low :).
		921	.Sp
		922	Setting a priority outside the range of \f(CW\(C`EV_MINPRI\(C'\fR to \f(CW\(C`EV_MAXPRI\(C'\fR is
		923	fine, as long as you do not mind that the priority value you query might
		924	or might not have been adjusted to be within valid range.
791	.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"	925	.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"	926	.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	927	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	928	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	929	to associate arbitrary data with your watcher. If you need more data and
…		…
816	\& struct my_io w = (struct my_io )w_;	950	\& struct my_io w = (struct my_io )w_;
817	\& ...	951	\& ...
818	\& }	952	\& }
819	.Ve	953	.Ve
820	.PP	954	.PP
821	More interesting and less C\-conformant ways of catsing your callback type	955	More interesting and less C\-conformant ways of casting your callback type
822	have been omitted....	956	instead have been omitted.
		957	.PP
		958	Another common scenario is having some data structure with multiple
		959	watchers:
		960	.PP
		961	.Vb 6
		962	\& struct my_biggy
		963	\& {
		964	\& int some_data;
		965	\& ev_timer t1;
		966	\& ev_timer t2;
		967	\& }
		968	.Ve
		969	.PP
		970	In this case getting the pointer to \f(CW\(C`my_biggy\(C'\fR is a bit more complicated,
		971	you need to use \f(CW\(C`offsetof\(C'\fR:
		972	.PP
		973	.Vb 1
		974	\& #include <stddef.h>
		975	.Ve
		976	.PP
		977	.Vb 6
		978	\& static void
		979	\& t1_cb (EV_P_ struct ev_timer *w, int revents)
		980	\& {
		981	\& struct my_biggy big = (struct my_biggy *
		982	\& (((char *)w) - offsetof (struct my_biggy, t1));
		983	\& }
		984	.Ve
		985	.PP
		986	.Vb 6
		987	\& static void
		988	\& t2_cb (EV_P_ struct ev_timer *w, int revents)
		989	\& {
		990	\& struct my_biggy big = (struct my_biggy *
		991	\& (((char *)w) - offsetof (struct my_biggy, t2));
		992	\& }
		993	.Ve
823	.SH "WATCHER TYPES"	994	.SH "WATCHER TYPES"
824	.IX Header "WATCHER TYPES"	995	.IX Header "WATCHER TYPES"
825	This section describes each watcher in detail, but will not repeat	996	This section describes each watcher in detail, but will not repeat
826	information given in the last section.	997	information given in the last section. Any initialisation/set macros,
		998	functions and members specific to the watcher type are explained.
		999	.PP
		1000	Members are additionally marked with either \fI[read\-only]\fR, meaning that,
		1001	while the watcher is active, you can look at the member and expect some
		1002	sensible content, but you must not modify it (you can modify it while the
		1003	watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
		1004	means you can expect it to have some sensible content while the watcher
		1005	is active, but you can also modify it. Modifying it may not do something
		1006	sensible or take immediate effect (or do anything at all), but libev will
		1007	not crash or malfunction in any way.
827	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable?"	1008	.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?"	1009	.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?"	1010	.IX Subsection "ev_io - is this file descriptor readable or writable?"
830	I/O watchers check whether a file descriptor is readable or writable	1011	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	1012	in each iteration of the event loop, or, more precisely, when reading
…		…
871	.IX Item "ev_io_set (ev_io *, int fd, int events)"	1052	.IX Item "ev_io_set (ev_io *, int fd, int events)"
872	.PD	1053	.PD
873	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The \f(CW\(C`fd\(C'\fR is the file descriptor to	1054	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	1055	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.	1056	\&\f(CW\(C`EV_READ \| EV_WRITE\(C'\fR to receive the given events.
		1057	.IP "int fd [read\-only]" 4
		1058	.IX Item "int fd [read-only]"
		1059	The file descriptor being watched.
		1060	.IP "int events [read\-only]" 4
		1061	.IX Item "int events [read-only]"
		1062	The events being watched.
876	.PP	1063	.PP
877	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well	1064	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	1065	readable, but only once. Since it is likely line\-buffered, you could
879	attempt to read a whole line in the callback:	1066	attempt to read a whole line in the callback.
880	.PP	1067	.PP
881	.Vb 6	1068	.Vb 6
882	\& static void	1069	\& static void
883	\& stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	1070	\& stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
884	\& {	1071	\& {
…		…
939	.IP "ev_timer_again (loop)" 4	1126	.IP "ev_timer_again (loop)" 4
940	.IX Item "ev_timer_again (loop)"	1127	.IX Item "ev_timer_again (loop)"
941	This will act as if the timer timed out and restart it again if it is	1128	This will act as if the timer timed out and restart it again if it is
942	repeating. The exact semantics are:	1129	repeating. The exact semantics are:
943	.Sp	1130	.Sp
		1131	If the timer is pending, its pending status is cleared.
		1132	.Sp
944	If the timer is started but nonrepeating, stop it.	1133	If the timer is started but nonrepeating, stop it (as if it timed out).
945	.Sp	1134	.Sp
946	If the timer is repeating, either start it if necessary (with the repeat	1135	If the timer is repeating, either start it if necessary (with the
947	value), or reset the running timer to the repeat value.	1136	\&\f(CW\(C`repeat\(C'\fR value), or reset the running timer to the \f(CW\(C`repeat\(C'\fR value.
948	.Sp	1137	.Sp
949	This sounds a bit complicated, but here is a useful and typical	1138	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	1139	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	1140	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	1141	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	1142	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	1143	\&\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	1144	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.	1145	socket, you can \f(CW\(C`ev_timer_stop\(C'\fR the timer, and \f(CW\(C`ev_timer_again\(C'\fR will
		1146	automatically restart it if need be.
		1147	.Sp
		1148	That means you can ignore the \f(CW\(C`after\(C'\fR value and \f(CW\(C`ev_timer_start\(C'\fR
		1149	altogether and only ever use the \f(CW\(C`repeat\(C'\fR value and \f(CW\(C`ev_timer_again\(C'\fR:
		1150	.Sp
		1151	.Vb 8
		1152	\& ev_timer_init (timer, callback, 0., 5.);
		1153	\& ev_timer_again (loop, timer);
		1154	\& ...
		1155	\& timer->again = 17.;
		1156	\& ev_timer_again (loop, timer);
		1157	\& ...
		1158	\& timer->again = 10.;
		1159	\& ev_timer_again (loop, timer);
		1160	.Ve
		1161	.Sp
		1162	This is more slightly efficient then stopping/starting the timer each time
		1163	you want to modify its timeout value.
		1164	.IP "ev_tstamp repeat [read\-write]" 4
		1165	.IX Item "ev_tstamp repeat [read-write]"
		1166	The current \f(CW\(C`repeat\(C'\fR value. Will be used each time the watcher times out
		1167	or \f(CW\(C`ev_timer_again\(C'\fR is called and determines the next timeout (if any),
		1168	which is also when any modifications are taken into account.
957	.PP	1169	.PP
958	Example: create a timer that fires after 60 seconds.	1170	Example: Create a timer that fires after 60 seconds.
959	.PP	1171	.PP
960	.Vb 5	1172	.Vb 5
961	\& static void	1173	\& static void
962	\& one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1174	\& one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
963	\& {	1175	\& {
…		…
969	\& struct ev_timer mytimer;	1181	\& struct ev_timer mytimer;
970	\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1182	\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
971	\& ev_timer_start (loop, &mytimer);	1183	\& ev_timer_start (loop, &mytimer);
972	.Ve	1184	.Ve
973	.PP	1185	.PP
974	Example: create a timeout timer that times out after 10 seconds of	1186	Example: Create a timeout timer that times out after 10 seconds of
975	inactivity.	1187	inactivity.
976	.PP	1188	.PP
977	.Vb 5	1189	.Vb 5
978	\& static void	1190	\& static void
979	\& timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1191	\& timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
…		…
1093	.IX Item "ev_periodic_again (loop, ev_periodic *)"	1305	.IX Item "ev_periodic_again (loop, ev_periodic *)"
1094	Simply stops and restarts the periodic watcher again. This is only useful	1306	Simply stops and restarts the periodic watcher again. This is only useful
1095	when you changed some parameters or the reschedule callback would return	1307	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	1308	a different time than the last time it was called (e.g. in a crond like
1097	program when the crontabs have changed).	1309	program when the crontabs have changed).
		1310	.IP "ev_tstamp interval [read\-write]" 4
		1311	.IX Item "ev_tstamp interval [read-write]"
		1312	The current interval value. Can be modified any time, but changes only
		1313	take effect when the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being
		1314	called.
		1315	.IP "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read\-write]" 4
		1316	.IX Item "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]"
		1317	The current reschedule callback, or \f(CW0\fR, if this functionality is
		1318	switched off. Can be changed any time, but changes only take effect when
		1319	the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being called.
1098	.PP	1320	.PP
1099	Example: call a callback every hour, or, more precisely, whenever the	1321	Example: Call a callback every hour, or, more precisely, whenever the
1100	system clock is divisible by 3600. The callback invocation times have	1322	system clock is divisible by 3600. The callback invocation times have
1101	potentially a lot of jittering, but good long-term stability.	1323	potentially a lot of jittering, but good long-term stability.
1102	.PP	1324	.PP
1103	.Vb 5	1325	.Vb 5
1104	\& static void	1326	\& static void
…		…
1112	\& struct ev_periodic hourly_tick;	1334	\& struct ev_periodic hourly_tick;
1113	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1335	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1114	\& ev_periodic_start (loop, &hourly_tick);	1336	\& ev_periodic_start (loop, &hourly_tick);
1115	.Ve	1337	.Ve
1116	.PP	1338	.PP
1117	Example: the same as above, but use a reschedule callback to do it:	1339	Example: The same as above, but use a reschedule callback to do it:
1118	.PP	1340	.PP
1119	.Vb 1	1341	.Vb 1
1120	\& #include <math.h>	1342	\& #include <math.h>
1121	.Ve	1343	.Ve
1122	.PP	1344	.PP
…		…
1130	.PP	1352	.PP
1131	.Vb 1	1353	.Vb 1
1132	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1354	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1133	.Ve	1355	.Ve
1134	.PP	1356	.PP
1135	Example: call a callback every hour, starting now:	1357	Example: Call a callback every hour, starting now:
1136	.PP	1358	.PP
1137	.Vb 4	1359	.Vb 4
1138	\& struct ev_periodic hourly_tick;	1360	\& struct ev_periodic hourly_tick;
1139	\& ev_periodic_init (&hourly_tick, clock_cb,	1361	\& ev_periodic_init (&hourly_tick, clock_cb,
1140	\& fmod (ev_now (loop), 3600.), 3600., 0);	1362	\& fmod (ev_now (loop), 3600.), 3600., 0);
…		…
1160	.IP "ev_signal_set (ev_signal *, int signum)" 4	1382	.IP "ev_signal_set (ev_signal *, int signum)" 4
1161	.IX Item "ev_signal_set (ev_signal *, int signum)"	1383	.IX Item "ev_signal_set (ev_signal *, int signum)"
1162	.PD	1384	.PD
1163	Configures the watcher to trigger on the given signal number (usually one	1385	Configures the watcher to trigger on the given signal number (usually one
1164	of the \f(CW\(C`SIGxxx\(C'\fR constants).	1386	of the \f(CW\(C`SIGxxx\(C'\fR constants).
		1387	.IP "int signum [read\-only]" 4
		1388	.IX Item "int signum [read-only]"
		1389	The signal the watcher watches out for.
1165	.ie n .Sh """ev_child"" \- watch out for process status changes"	1390	.ie n .Sh """ev_child"" \- watch out for process status changes"
1166	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"	1391	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1167	.IX Subsection "ev_child - watch out for process status changes"	1392	.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	1393	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).	1394	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	1402	\&\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	1403	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	1404	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	1405	\&\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.	1406	process causing the status change.
		1407	.IP "int pid [read\-only]" 4
		1408	.IX Item "int pid [read-only]"
		1409	The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
		1410	.IP "int rpid [read\-write]" 4
		1411	.IX Item "int rpid [read-write]"
		1412	The process id that detected a status change.
		1413	.IP "int rstatus [read\-write]" 4
		1414	.IX Item "int rstatus [read-write]"
		1415	The process exit/trace status caused by \f(CW\(C`rpid\(C'\fR (see your systems
		1416	\&\f(CW\(C`waitpid\(C'\fR and \f(CW\(C`sys/wait.h\(C'\fR documentation for details).
1182	.PP	1417	.PP
1183	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.	1418	Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1184	.PP	1419	.PP
1185	.Vb 5	1420	.Vb 5
1186	\& static void	1421	\& static void
1187	\& sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1422	\& sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1188	\& {	1423	\& {
…		…
1193	.Vb 3	1428	.Vb 3
1194	\& struct ev_signal signal_watcher;	1429	\& struct ev_signal signal_watcher;
1195	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1430	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1196	\& ev_signal_start (loop, &sigint_cb);	1431	\& ev_signal_start (loop, &sigint_cb);
1197	.Ve	1432	.Ve
		1433	.ie n .Sh """ev_stat"" \- did the file attributes just change?"
		1434	.el .Sh "\f(CWev_stat\fP \- did the file attributes just change?"
		1435	.IX Subsection "ev_stat - did the file attributes just change?"
		1436	This watches a filesystem path for attribute changes. That is, it calls
		1437	\&\f(CW\(C`stat\(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed
		1438	compared to the last time, invoking the callback if it did.
		1439	.PP
		1440	The path does not need to exist: changing from \(L"path exists\(R" to \*(L"path does
		1441	not exist\(R" is a status change like any other. The condition \(L"path does
		1442	not exist\(R" is signified by the \f(CW\(C`st_nlink\*(C'\fR field being zero (which is
		1443	otherwise always forced to be at least one) and all the other fields of
		1444	the stat buffer having unspecified contents.
		1445	.PP
		1446	The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is
		1447	relative and your working directory changes, the behaviour is undefined.
		1448	.PP
		1449	Since there is no standard to do this, the portable implementation simply
		1450	calls \f(CW\(C`stat (2)\(C'\fR regularly on the path to see if it changed somehow. You
		1451	can specify a recommended polling interval for this case. If you specify
		1452	a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
		1453	unspecified default\fR value will be used (which you can expect to be around
		1454	five seconds, although this might change dynamically). Libev will also
		1455	impose a minimum interval which is currently around \f(CW0.1\fR, but thats
		1456	usually overkill.
		1457	.PP
		1458	This watcher type is not meant for massive numbers of stat watchers,
		1459	as even with OS-supported change notifications, this can be
		1460	resource\-intensive.
		1461	.PP
		1462	At the time of this writing, only the Linux inotify interface is
		1463	implemented (implementing kqueue support is left as an exercise for the
		1464	reader). Inotify will be used to give hints only and should not change the
		1465	semantics of \f(CW\(C`ev_stat\(C'\fR watchers, which means that libev sometimes needs
		1466	to fall back to regular polling again even with inotify, but changes are
		1467	usually detected immediately, and if the file exists there will be no
		1468	polling.
		1469	.IP "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)" 4
		1470	.IX Item "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)"
		1471	.PD 0
		1472	.IP "ev_stat_set (ev_stat , const char path, ev_tstamp interval)" 4
		1473	.IX Item "ev_stat_set (ev_stat , const char path, ev_tstamp interval)"
		1474	.PD
		1475	Configures the watcher to wait for status changes of the given
		1476	\&\f(CW\(C`path\(C'\fR. The \f(CW\(C`interval\(C'\fR is a hint on how quickly a change is expected to
		1477	be detected and should normally be specified as \f(CW0\fR to let libev choose
		1478	a suitable value. The memory pointed to by \f(CW\(C`path\(C'\fR must point to the same
		1479	path for as long as the watcher is active.
		1480	.Sp
		1481	The callback will be receive \f(CW\(C`EV_STAT\(C'\fR when a change was detected,
		1482	relative to the attributes at the time the watcher was started (or the
		1483	last change was detected).
		1484	.IP "ev_stat_stat (ev_stat *)" 4
		1485	.IX Item "ev_stat_stat (ev_stat *)"
		1486	Updates the stat buffer immediately with new values. If you change the
		1487	watched path in your callback, you could call this fucntion to avoid
		1488	detecting this change (while introducing a race condition). Can also be
		1489	useful simply to find out the new values.
		1490	.IP "ev_statdata attr [read\-only]" 4
		1491	.IX Item "ev_statdata attr [read-only]"
		1492	The most-recently detected attributes of the file. Although the type is of
		1493	\&\f(CW\(C`ev_statdata\(C'\fR, this is usually the (or one of the) \f(CW\(C`struct stat\(C'\fR types
		1494	suitable for your system. If the \f(CW\(C`st_nlink\(C'\fR member is \f(CW0\fR, then there
		1495	was some error while \f(CW\(C`stat\(C'\fRing the file.
		1496	.IP "ev_statdata prev [read\-only]" 4
		1497	.IX Item "ev_statdata prev [read-only]"
		1498	The previous attributes of the file. The callback gets invoked whenever
		1499	\&\f(CW\(C`prev\(C'\fR != \f(CW\(C`attr\(C'\fR.
		1500	.IP "ev_tstamp interval [read\-only]" 4
		1501	.IX Item "ev_tstamp interval [read-only]"
		1502	The specified interval.
		1503	.IP "const char *path [read\-only]" 4
		1504	.IX Item "const char *path [read-only]"
		1505	The filesystem path that is being watched.
		1506	.PP
		1507	Example: Watch \f(CW\(C`/etc/passwd\(C'\fR for attribute changes.
		1508	.PP
		1509	.Vb 15
		1510	\& static void
		1511	\& passwd_cb (struct ev_loop loop, ev_stat w, int revents)
		1512	\& {
		1513	\& /* /etc/passwd changed in some way */
		1514	\& if (w->attr.st_nlink)
		1515	\& {
		1516	\& printf ("passwd current size %ld\en", (long)w->attr.st_size);
		1517	\& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime);
		1518	\& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime);
		1519	\& }
		1520	\& else
		1521	\& /* you shalt not abuse printf for puts */
		1522	\& puts ("wow, /etc/passwd is not there, expect problems. "
		1523	\& "if this is windows, they already arrived\en");
		1524	\& }
		1525	.Ve
		1526	.PP
		1527	.Vb 2
		1528	\& ...
		1529	\& ev_stat passwd;
		1530	.Ve
		1531	.PP
		1532	.Vb 2
		1533	\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
		1534	\& ev_stat_start (loop, &passwd);
		1535	.Ve
1198	.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."	1536	.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..."	1537	.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..."	1538	.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	1539	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	1540	priority are pending (prepare, check and other idle watchers do not
1203	as your process is busy handling sockets or timeouts (or even signals,	1541	count).
1204	imagine) it will not be triggered. But when your process is idle all idle	1542	.PP
1205	watchers are being called again and again, once per event loop iteration \-	1543	That is, as long as your process is busy handling sockets or timeouts
		1544	(or even signals, imagine) of the same or higher priority it will not be
		1545	triggered. But when your process is idle (or only lower-priority watchers
		1546	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	1547	iteration \- until stopped, that is, or your process receives more events
1207	busy.	1548	and becomes busy again with higher priority stuff.
1208	.PP	1549	.PP
1209	The most noteworthy effect is that as long as any idle watchers are	1550	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.	1551	active, the process will not block when waiting for new events.
1211	.PP	1552	.PP
1212	Apart from keeping your process non-blocking (which is a useful	1553	Apart from keeping your process non-blocking (which is a useful
…		…
1217	.IX Item "ev_idle_init (ev_signal *, callback)"	1558	.IX Item "ev_idle_init (ev_signal *, callback)"
1218	Initialises and configures the idle watcher \- it has no parameters of any	1559	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,	1560	kind. There is a \f(CW\(C`ev_idle_set\(C'\fR macro, but using it is utterly pointless,
1220	believe me.	1561	believe me.
1221	.PP	1562	.PP
1222	Example: dynamically allocate an \f(CW\(C`ev_idle\(C'\fR, start it, and in the	1563	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.	1564	callback, free it. Also, use no error checking, as usual.
1224	.PP	1565	.PP
1225	.Vb 7	1566	.Vb 7
1226	\& static void	1567	\& static void
1227	\& idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1568	\& idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1228	\& {	1569	\& {
…		…
1242	.IX Subsection "ev_prepare and ev_check - customise your event loop!"	1583	.IX Subsection "ev_prepare and ev_check - customise your event loop!"
1243	Prepare and check watchers are usually (but not always) used in tandem:	1584	Prepare and check watchers are usually (but not always) used in tandem:
1244	prepare watchers get invoked before the process blocks and check watchers	1585	prepare watchers get invoked before the process blocks and check watchers
1245	afterwards.	1586	afterwards.
1246	.PP	1587	.PP
		1588	You \fImust not\fR call \f(CW\(C`ev_loop\(C'\fR or similar functions that enter
		1589	the current event loop from either \f(CW\(C`ev_prepare\(C'\fR or \f(CW\(C`ev_check\(C'\fR
		1590	watchers. Other loops than the current one are fine, however. The
		1591	rationale behind this is that you do not need to check for recursion in
		1592	those watchers, i.e. the sequence will always be \f(CW\(C`ev_prepare\(C'\fR, blocking,
		1593	\&\f(CW\(C`ev_check\(C'\fR so if you have one watcher of each kind they will always be
		1594	called in pairs bracketing the blocking call.
		1595	.PP
1247	Their main purpose is to integrate other event mechanisms into libev and	1596	Their main purpose is to integrate other event mechanisms into libev and
1248	their use is somewhat advanced. This could be used, for example, to track	1597	their use is somewhat advanced. This could be used, for example, to track
1249	variable changes, implement your own watchers, integrate net-snmp or a	1598	variable changes, implement your own watchers, integrate net-snmp or a
1250	coroutine library and lots more.	1599	coroutine library and lots more. They are also occasionally useful if
		1600	you cache some data and want to flush it before blocking (for example,
		1601	in X programs you might want to do an \f(CW\(C`XFlush ()\(C'\fR in an \f(CW\(C`ev_prepare\(C'\fR
		1602	watcher).
1251	.PP	1603	.PP
1252	This is done by examining in each prepare call which file descriptors need	1604	This is done by examining in each prepare call which file descriptors need
1253	to be watched by the other library, registering \f(CW\(C`ev_io\(C'\fR watchers for	1605	to be watched by the other library, registering \f(CW\(C`ev_io\(C'\fR watchers for
1254	them and starting an \f(CW\(C`ev_timer\(C'\fR watcher for any timeouts (many libraries	1606	them and starting an \f(CW\(C`ev_timer\(C'\fR watcher for any timeouts (many libraries
1255	provide just this functionality). Then, in the check watcher you check for	1607	provide just this functionality). Then, in the check watcher you check for
…		…
1274	.PD	1626	.PD
1275	Initialises and configures the prepare or check watcher \- they have no	1627	Initialises and configures the prepare or check watcher \- they have no
1276	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR	1628	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR
1277	macros, but using them is utterly, utterly and completely pointless.	1629	macros, but using them is utterly, utterly and completely pointless.
1278	.PP	1630	.PP
1279	Example: TODO.	1631	Example: To include a library such as adns, you would add \s-1IO\s0 watchers
		1632	and a timeout watcher in a prepare handler, as required by libadns, and
		1633	in a check watcher, destroy them and call into libadns. What follows is
		1634	pseudo-code only of course:
		1635	.PP
		1636	.Vb 2
		1637	\& static ev_io iow [nfd];
		1638	\& static ev_timer tw;
		1639	.Ve
		1640	.PP
		1641	.Vb 9
		1642	\& static void
		1643	\& io_cb (ev_loop loop, ev_io w, int revents)
		1644	\& {
		1645	\& // set the relevant poll flags
		1646	\& // could also call adns_processreadable etc. here
		1647	\& struct pollfd fd = (struct pollfd )w->data;
		1648	\& if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1649	\& if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1650	\& }
		1651	.Ve
		1652	.PP
		1653	.Vb 8
		1654	\& // create io watchers for each fd and a timer before blocking
		1655	\& static void
		1656	\& adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
		1657	\& {
		1658	\& int timeout = 3600000;
		1659	\& struct pollfd fds [nfd];
		1660	\& // actual code will need to loop here and realloc etc.
		1661	\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
		1662	.Ve
		1663	.PP
		1664	.Vb 3
		1665	\& /* the callback is illegal, but won't be called as we stop during check */
		1666	\& ev_timer_init (&tw, 0, timeout * 1e-3);
		1667	\& ev_timer_start (loop, &tw);
		1668	.Ve
		1669	.PP
		1670	.Vb 6
		1671	\& // create on ev_io per pollfd
		1672	\& for (int i = 0; i < nfd; ++i)
		1673	\& {
		1674	\& ev_io_init (iow + i, io_cb, fds [i].fd,
		1675	\& ((fds [i].events & POLLIN ? EV_READ : 0)
		1676	\& \| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
		1677	.Ve
		1678	.PP
		1679	.Vb 5
		1680	\& fds [i].revents = 0;
		1681	\& iow [i].data = fds + i;
		1682	\& ev_io_start (loop, iow + i);
		1683	\& }
		1684	\& }
		1685	.Ve
		1686	.PP
		1687	.Vb 5
		1688	\& // stop all watchers after blocking
		1689	\& static void
		1690	\& adns_check_cb (ev_loop loop, ev_check w, int revents)
		1691	\& {
		1692	\& ev_timer_stop (loop, &tw);
		1693	.Ve
		1694	.PP
		1695	.Vb 2
		1696	\& for (int i = 0; i < nfd; ++i)
		1697	\& ev_io_stop (loop, iow + i);
		1698	.Ve
		1699	.PP
		1700	.Vb 2
		1701	\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1702	\& }
		1703	.Ve
1280	.ie n .Sh """ev_embed"" \- when one backend isn't enough..."	1704	.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1281	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."	1705	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1282	.IX Subsection "ev_embed - when one backend isn't enough..."	1706	.IX Subsection "ev_embed - when one backend isn't enough..."
1283	This is a rather advanced watcher type that lets you embed one event loop	1707	This is a rather advanced watcher type that lets you embed one event loop
1284	into another (currently only \f(CW\(C`ev_io\(C'\fR events are supported in the embedded	1708	into another (currently only \f(CW\(C`ev_io\(C'\fR events are supported in the embedded
…		…
1367	.IP "ev_embed_sweep (loop, ev_embed *)" 4	1791	.IP "ev_embed_sweep (loop, ev_embed *)" 4
1368	.IX Item "ev_embed_sweep (loop, ev_embed *)"	1792	.IX Item "ev_embed_sweep (loop, ev_embed *)"
1369	Make a single, non-blocking sweep over the embedded loop. This works	1793	Make a single, non-blocking sweep over the embedded loop. This works
1370	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most	1794	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most
1371	apropriate way for embedded loops.	1795	apropriate way for embedded loops.
		1796	.IP "struct ev_loop *loop [read\-only]" 4
		1797	.IX Item "struct ev_loop *loop [read-only]"
		1798	The embedded event loop.
		1799	.ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork"
		1800	.el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
		1801	.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
		1802	Fork watchers are called when a \f(CW\(C`fork ()\(C'\fR was detected (usually because
		1803	whoever is a good citizen cared to tell libev about it by calling
		1804	\&\f(CW\(C`ev_default_fork\(C'\fR or \f(CW\(C`ev_loop_fork\(C'\fR). The invocation is done before the
		1805	event loop blocks next and before \f(CW\(C`ev_check\(C'\fR watchers are being called,
		1806	and only in the child after the fork. If whoever good citizen calling
		1807	\&\f(CW\(C`ev_default_fork\(C'\fR cheats and calls it in the wrong process, the fork
		1808	handlers will be invoked, too, of course.
		1809	.IP "ev_fork_init (ev_signal *, callback)" 4
		1810	.IX Item "ev_fork_init (ev_signal *, callback)"
		1811	Initialises and configures the fork watcher \- it has no parameters of any
		1812	kind. There is a \f(CW\(C`ev_fork_set\(C'\fR macro, but using it is utterly pointless,
		1813	believe me.
1372	.SH "OTHER FUNCTIONS"	1814	.SH "OTHER FUNCTIONS"
1373	.IX Header "OTHER FUNCTIONS"	1815	.IX Header "OTHER FUNCTIONS"
1374	There are some other functions of possible interest. Described. Here. Now.	1816	There are some other functions of possible interest. Described. Here. Now.
1375	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4	1817	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
1376	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"	1818	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
…		…
1515	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.	1957	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.
1516	.ie n .IP "w\->sweep () ""ev::embed"" only" 4	1958	.ie n .IP "w\->sweep () ""ev::embed"" only" 4
1517	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4	1959	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
1518	.IX Item "w->sweep () ev::embed only"	1960	.IX Item "w->sweep () ev::embed only"
1519	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.	1961	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.
		1962	.ie n .IP "w\->update () ""ev::stat"" only" 4
		1963	.el .IP "w\->update () \f(CWev::stat\fR only" 4
		1964	.IX Item "w->update () ev::stat only"
		1965	Invokes \f(CW\(C`ev_stat_stat\(C'\fR.
1520	.RE	1966	.RE
1521	.RS 4	1967	.RS 4
1522	.RE	1968	.RE
1523	.PP	1969	.PP
1524	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in	1970	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
…		…
1541	\& : io (this, &myclass::io_cb),	1987	\& : io (this, &myclass::io_cb),
1542	\& idle (this, &myclass::idle_cb)	1988	\& idle (this, &myclass::idle_cb)
1543	\& {	1989	\& {
1544	\& io.start (fd, ev::READ);	1990	\& io.start (fd, ev::READ);
1545	\& }	1991	\& }
		1992	.Ve
		1993	.SH "MACRO MAGIC"
		1994	.IX Header "MACRO MAGIC"
		1995	Libev can be compiled with a variety of options, the most fundemantal is
		1996	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR. This option determines wether (most) functions and
		1997	callbacks have an initial \f(CW\(C`struct ev_loop \*(C'\fR argument.
		1998	.PP
		1999	To make it easier to write programs that cope with either variant, the
		2000	following macros are defined:
		2001	.ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4
		2002	.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
		2003	.IX Item "EV_A, EV_A_"
		2004	This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
		2005	loop argument\(R"). The \f(CW\(C`EV_A\*(C'\fR form is used when this is the sole argument,
		2006	\&\f(CW\(C`EV_A_\(C'\fR is used when other arguments are following. Example:
		2007	.Sp
		2008	.Vb 3
		2009	\& ev_unref (EV_A);
		2010	\& ev_timer_add (EV_A_ watcher);
		2011	\& ev_loop (EV_A_ 0);
		2012	.Ve
		2013	.Sp
		2014	It assumes the variable \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR is in scope,
		2015	which is often provided by the following macro.
		2016	.ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4
		2017	.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
		2018	.IX Item "EV_P, EV_P_"
		2019	This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
		2020	loop parameter\(R"). The \f(CW\(C`EV_P\*(C'\fR form is used when this is the sole parameter,
		2021	\&\f(CW\(C`EV_P_\(C'\fR is used when other parameters are following. Example:
		2022	.Sp
		2023	.Vb 2
		2024	\& // this is how ev_unref is being declared
		2025	\& static void ev_unref (EV_P);
		2026	.Ve
		2027	.Sp
		2028	.Vb 2
		2029	\& // this is how you can declare your typical callback
		2030	\& static void cb (EV_P_ ev_timer *w, int revents)
		2031	.Ve
		2032	.Sp
		2033	It declares a parameter \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR, quite
		2034	suitable for use with \f(CW\(C`EV_A\(C'\fR.
		2035	.ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4
		2036	.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
		2037	.IX Item "EV_DEFAULT, EV_DEFAULT_"
		2038	Similar to the other two macros, this gives you the value of the default
		2039	loop, if multiple loops are supported (\(L"ev loop default\(R").
		2040	.PP
		2041	Example: Declare and initialise a check watcher, utilising the above
		2042	macros so it will work regardless of wether multiple loops are supported
		2043	or not.
		2044	.PP
		2045	.Vb 5
		2046	\& static void
		2047	\& check_cb (EV_P_ ev_timer *w, int revents)
		2048	\& {
		2049	\& ev_check_stop (EV_A_ w);
		2050	\& }
		2051	.Ve
		2052	.PP
		2053	.Vb 4
		2054	\& ev_check check;
		2055	\& ev_check_init (&check, check_cb);
		2056	\& ev_check_start (EV_DEFAULT_ &check);
		2057	\& ev_loop (EV_DEFAULT_ 0);
1546	.Ve	2058	.Ve
1547	.SH "EMBEDDING"	2059	.SH "EMBEDDING"
1548	.IX Header "EMBEDDING"	2060	.IX Header "EMBEDDING"
1549	Libev can (and often is) directly embedded into host	2061	Libev can (and often is) directly embedded into host
1550	applications. Examples of applications that embed it include the Deliantra	2062	applications. Examples of applications that embed it include the Deliantra
…		…
1599	.Vb 1	2111	.Vb 1
1600	\& ev_win32.c required on win32 platforms only	2112	\& ev_win32.c required on win32 platforms only
1601	.Ve	2113	.Ve
1602	.PP	2114	.PP
1603	.Vb 5	2115	.Vb 5
1604	\& ev_select.c only when select backend is enabled (which is is by default)	2116	\& ev_select.c only when select backend is enabled (which is enabled by default)
1605	\& ev_poll.c only when poll backend is enabled (disabled by default)	2117	\& ev_poll.c only when poll backend is enabled (disabled by default)
1606	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)	2118	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
1607	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	2119	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1608	\& ev_port.c only when the solaris port backend is enabled (disabled by default)	2120	\& ev_port.c only when the solaris port backend is enabled (disabled by default)
1609	.Ve	2121	.Ve
1610	.PP	2122	.PP
1611	\&\fIev.c\fR includes the backend files directly when enabled, so you only need	2123	\&\fIev.c\fR includes the backend files directly when enabled, so you only need
1612	to compile a single file.	2124	to compile this single file.
1613	.PP	2125	.PP
1614	\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR	2126	\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR
1615	.IX Subsection "LIBEVENT COMPATIBILITY API"	2127	.IX Subsection "LIBEVENT COMPATIBILITY API"
1616	.PP	2128	.PP
1617	To include the libevent compatibility \s-1API\s0, also include:	2129	To include the libevent compatibility \s-1API\s0, also include:
…		…
1638	\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR	2150	\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR
1639	.IX Subsection "AUTOCONF SUPPORT"	2151	.IX Subsection "AUTOCONF SUPPORT"
1640	.PP	2152	.PP
1641	Instead of using \f(CW\(C`EV_STANDALONE=1\(C'\fR and providing your config in	2153	Instead of using \f(CW\(C`EV_STANDALONE=1\(C'\fR and providing your config in
1642	whatever way you want, you can also \f(CW\(C`m4_include([libev.m4])\(C'\fR in your	2154	whatever way you want, you can also \f(CW\(C`m4_include([libev.m4])\(C'\fR in your
1643	\&\fIconfigure.ac\fR and leave \f(CW\(C`EV_STANDALONE\(C'\fR off. \fIev.c\fR will then include	2155	\&\fIconfigure.ac\fR and leave \f(CW\(C`EV_STANDALONE\(C'\fR undefined. \fIev.c\fR will then
1644	\&\fIconfig.h\fR and configure itself accordingly.	2156	include \fIconfig.h\fR and configure itself accordingly.
1645	.PP	2157	.PP
1646	For this of course you need the m4 file:	2158	For this of course you need the m4 file:
1647	.PP	2159	.PP
1648	.Vb 1	2160	.Vb 1
1649	\& libev.m4	2161	\& libev.m4
…		…
1730	otherwise another method will be used as fallback. This is the preferred	2242	otherwise another method will be used as fallback. This is the preferred
1731	backend for Solaris 10 systems.	2243	backend for Solaris 10 systems.
1732	.IP "\s-1EV_USE_DEVPOLL\s0" 4	2244	.IP "\s-1EV_USE_DEVPOLL\s0" 4
1733	.IX Item "EV_USE_DEVPOLL"	2245	.IX Item "EV_USE_DEVPOLL"
1734	reserved for future expansion, works like the \s-1USE\s0 symbols above.	2246	reserved for future expansion, works like the \s-1USE\s0 symbols above.
		2247	.IP "\s-1EV_USE_INOTIFY\s0" 4
		2248	.IX Item "EV_USE_INOTIFY"
		2249	If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify
		2250	interface to speed up \f(CW\(C`ev_stat\(C'\fR watchers. Its actual availability will
		2251	be detected at runtime.
1735	.IP "\s-1EV_H\s0" 4	2252	.IP "\s-1EV_H\s0" 4
1736	.IX Item "EV_H"	2253	.IX Item "EV_H"
1737	The name of the \fIev.h\fR header file used to include it. The default if	2254	The name of the \fIev.h\fR header file used to include it. The default if
1738	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This	2255	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
1739	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.	2256	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
…		…
1757	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions	2274	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
1758	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create	2275	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create
1759	additional independent event loops. Otherwise there will be no support	2276	additional independent event loops. Otherwise there will be no support
1760	for multiple event loops and there is no first event loop pointer	2277	for multiple event loops and there is no first event loop pointer
1761	argument. Instead, all functions act on the single default loop.	2278	argument. Instead, all functions act on the single default loop.
1762	.IP "\s-1EV_PERIODICS\s0" 4	2279	.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
1763	.IX Item "EV_PERIODICS"	2280	.IX Item "EV_PERIODIC_ENABLE"
1764	If undefined or defined to be \f(CW1\fR, then periodic timers are supported,	2281	If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
1765	otherwise not. This saves a few kb of code.	2282	defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
		2283	code.
		2284	.IP "\s-1EV_IDLE_ENABLE\s0" 4
		2285	.IX Item "EV_IDLE_ENABLE"
		2286	If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If
		2287	defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
		2288	code.
		2289	.IP "\s-1EV_EMBED_ENABLE\s0" 4
		2290	.IX Item "EV_EMBED_ENABLE"
		2291	If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
		2292	defined to be \f(CW0\fR, then they are not.
		2293	.IP "\s-1EV_STAT_ENABLE\s0" 4
		2294	.IX Item "EV_STAT_ENABLE"
		2295	If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
		2296	defined to be \f(CW0\fR, then they are not.
		2297	.IP "\s-1EV_FORK_ENABLE\s0" 4
		2298	.IX Item "EV_FORK_ENABLE"
		2299	If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If
		2300	defined to be \f(CW0\fR, then they are not.
		2301	.IP "\s-1EV_MINIMAL\s0" 4
		2302	.IX Item "EV_MINIMAL"
		2303	If you need to shave off some kilobytes of code at the expense of some
		2304	speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
		2305	some inlining decisions, saves roughly 30% codesize of amd64.
		2306	.IP "\s-1EV_PID_HASHSIZE\s0" 4
		2307	.IX Item "EV_PID_HASHSIZE"
		2308	\&\f(CW\(C`ev_child\(C'\fR watchers use a small hash table to distribute workload by
		2309	pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\(C`EV_MINIMAL\(C'\fR), usually more
		2310	than enough. If you need to manage thousands of children you might want to
		2311	increase this value (\fImust\fR be a power of two).
		2312	.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
		2313	.IX Item "EV_INOTIFY_HASHSIZE"
		2314	\&\f(CW\(C`ev_staz\(C'\fR watchers use a small hash table to distribute workload by
		2315	inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\(C`EV_MINIMAL\(C'\fR),
		2316	usually more than enough. If you need to manage thousands of \f(CW\(C`ev_stat\(C'\fR
		2317	watchers you might want to increase this value (\fImust\fR be a power of
		2318	two).
1766	.IP "\s-1EV_COMMON\s0" 4	2319	.IP "\s-1EV_COMMON\s0" 4
1767	.IX Item "EV_COMMON"	2320	.IX Item "EV_COMMON"
1768	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining	2321	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining
1769	this macro to a something else you can include more and other types of	2322	this macro to a something else you can include more and other types of
1770	members. You have to define it each time you include one of the files,	2323	members. You have to define it each time you include one of the files,
…		…
1775	.Vb 3	2328	.Vb 3
1776	\& #define EV_COMMON \e	2329	\& #define EV_COMMON \e
1777	\& SV self; / contains this struct */ \e	2330	\& SV self; / contains this struct */ \e
1778	\& SV cb_sv, fh /* note no trailing ";" */	2331	\& SV cb_sv, fh /* note no trailing ";" */
1779	.Ve	2332	.Ve
1780	.IP "\s-1EV_CB_DECLARE\s0(type)" 4	2333	.IP "\s-1EV_CB_DECLARE\s0 (type)" 4
1781	.IX Item "EV_CB_DECLARE(type)"	2334	.IX Item "EV_CB_DECLARE (type)"
1782	.PD 0	2335	.PD 0
1783	.IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4	2336	.IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4
1784	.IX Item "EV_CB_INVOKE(watcher,revents)"	2337	.IX Item "EV_CB_INVOKE (watcher, revents)"
1785	.IP "ev_set_cb(ev,cb)" 4	2338	.IP "ev_set_cb (ev, cb)" 4
1786	.IX Item "ev_set_cb(ev,cb)"	2339	.IX Item "ev_set_cb (ev, cb)"
1787	.PD	2340	.PD
1788	Can be used to change the callback member declaration in each watcher,	2341	Can be used to change the callback member declaration in each watcher,
1789	and the way callbacks are invoked and set. Must expand to a struct member	2342	and the way callbacks are invoked and set. Must expand to a struct member
1790	definition and a statement, respectively. See the \fIev.v\fR header file for	2343	definition and a statement, respectively. See the \fIev.v\fR header file for
1791	their default definitions. One possible use for overriding these is to	2344	their default definitions. One possible use for overriding these is to
1792	avoid the ev_loop pointer as first argument in all cases, or to use method	2345	avoid the \f(CW\(C`struct ev_loop \*(C'\fR as first argument in all cases, or to use
1793	calls instead of plain function calls in \*(C+.	2346	method calls instead of plain function calls in \*(C+.
1794	.Sh "\s-1EXAMPLES\s0"	2347	.Sh "\s-1EXAMPLES\s0"
1795	.IX Subsection "EXAMPLES"	2348	.IX Subsection "EXAMPLES"
1796	For a real-world example of a program the includes libev	2349	For a real-world example of a program the includes libev
1797	verbatim, you can have a look at the \s-1EV\s0 perl module	2350	verbatim, you can have a look at the \s-1EV\s0 perl module
1798	(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in	2351	(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
…		…
1800	interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file	2353	interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
1801	will be compiled. It is pretty complex because it provides its own header	2354	will be compiled. It is pretty complex because it provides its own header
1802	file.	2355	file.
1803	.Sp	2356	.Sp
1804	The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file	2357	The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
1805	that everybody includes and which overrides some autoconf choices:	2358	that everybody includes and which overrides some configure choices:
1806	.Sp	2359	.Sp
1807	.Vb 4	2360	.Vb 9
		2361	\& #define EV_MINIMAL 1
1808	\& #define EV_USE_POLL 0	2362	\& #define EV_USE_POLL 0
1809	\& #define EV_MULTIPLICITY 0	2363	\& #define EV_MULTIPLICITY 0
1810	\& #define EV_PERIODICS 0	2364	\& #define EV_PERIODIC_ENABLE 0
		2365	\& #define EV_STAT_ENABLE 0
		2366	\& #define EV_FORK_ENABLE 0
1811	\& #define EV_CONFIG_H <config.h>	2367	\& #define EV_CONFIG_H <config.h>
		2368	\& #define EV_MINPRI 0
		2369	\& #define EV_MAXPRI 0
1812	.Ve	2370	.Ve
1813	.Sp	2371	.Sp
1814	.Vb 1	2372	.Vb 1
1815	\& #include "ev++.h"	2373	\& #include "ev++.h"
1816	.Ve	2374	.Ve
…		…
1819	.Sp	2377	.Sp
1820	.Vb 2	2378	.Vb 2
1821	\& #include "ev_cpp.h"	2379	\& #include "ev_cpp.h"
1822	\& #include "ev.c"	2380	\& #include "ev.c"
1823	.Ve	2381	.Ve
		2382	.SH "COMPLEXITIES"
		2383	.IX Header "COMPLEXITIES"
		2384	In this section the complexities of (many of) the algorithms used inside
		2385	libev will be explained. For complexity discussions about backends see the
		2386	documentation for \f(CW\(C`ev_default_init\(C'\fR.
		2387	.RS 4
		2388	.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
		2389	.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
		2390	.PD 0
		2391	.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4
		2392	.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
		2393	.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
		2394	.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
		2395	.IP "Stopping check/prepare/idle watchers: O(1)" 4
		2396	.IX Item "Stopping check/prepare/idle watchers: O(1)"
		2397	.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
		2398	.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"
		2399	.IP "Finding the next timer per loop iteration: O(1)" 4
		2400	.IX Item "Finding the next timer per loop iteration: O(1)"
		2401	.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
		2402	.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
		2403	.IP "Activating one watcher: O(1)" 4
		2404	.IX Item "Activating one watcher: O(1)"
		2405	.RE
		2406	.RS 4
		2407	.PD
1824	.SH "AUTHOR"	2408	.SH "AUTHOR"
1825	.IX Header "AUTHOR"	2409	.IX Header "AUTHOR"
1826	Marc Lehmann <libev@schmorp.de>.	2410	Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.3 (file contents): Revision 1.17 by root, Sat Nov 24 16:31:45 2007 UTC vs. Revision 1.37 by root, Fri Dec 7 16:49:49 2007 UTC

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Comparing libev/ev.3 (file contents):
Revision 1.17 by root, Sat Nov 24 16:31:45 2007 UTC vs.
Revision 1.37 by root, Fri Dec 7 16:49:49 2007 UTC