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

Comparing libev/ev.3 (file contents):
Revision 1.20 by root, Mon Nov 26 09:52:14 2007 UTC vs.
Revision 1.34 by root, Thu Nov 29 12:21:21 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 "2007-11-29" "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	\& {
…		…
448	Similar to \f(CW\(C`ev_default_loop\(C'\fR, but always creates a new event loop that is	514	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	515	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	516	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).	517	undefined behaviour (or a failed assertion if assertions are enabled).
452	.Sp	518	.Sp
453	Example: try to create a event loop that uses epoll and nothing else.	519	Example: Try to create a event loop that uses epoll and nothing else.
454	.Sp	520	.Sp
455	.Vb 3	521	.Vb 3
456	\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	522	\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
457	\& if (!epoller)	523	\& if (!epoller)
458	\& fatal ("no epoll found here, maybe it hides under your chair");	524	\& fatal ("no epoll found here, maybe it hides under your chair");
…		…
556	\& be handled here by queueing them when their watcher gets executed.	622	\& be handled here by queueing them when their watcher gets executed.
557	\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	623	\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
558	\& were used, return, otherwise continue with step *.	624	\& were used, return, otherwise continue with step *.
559	.Ve	625	.Ve
560	.Sp	626	.Sp
561	Example: queue some jobs and then loop until no events are outsanding	627	Example: Queue some jobs and then loop until no events are outsanding
562	anymore.	628	anymore.
563	.Sp	629	.Sp
564	.Vb 4	630	.Vb 4
565	\& ... queue jobs here, make sure they register event watchers as long	631	\& ... 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..)	632	\& ... 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	654	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	655	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	656	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.	657	libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.
592	.Sp	658	.Sp
593	Example: create a signal watcher, but keep it from keeping \f(CW\(C`ev_loop\(C'\fR	659	Example: Create a signal watcher, but keep it from keeping \f(CW\(C`ev_loop\(C'\fR
594	running when nothing else is active.	660	running when nothing else is active.
595	.Sp	661	.Sp
596	.Vb 4	662	.Vb 4
597	\& struct dv_signal exitsig;	663	\& struct ev_signal exitsig;
598	\& ev_signal_init (&exitsig, sig_cb, SIGINT);	664	\& ev_signal_init (&exitsig, sig_cb, SIGINT);
599	\& ev_signal_start (myloop, &exitsig);	665	\& ev_signal_start (loop, &exitsig);
600	\& evf_unref (myloop);	666	\& evf_unref (loop);
601	.Ve	667	.Ve
602	.Sp	668	.Sp
603	Example: for some weird reason, unregister the above signal handler again.	669	Example: For some weird reason, unregister the above signal handler again.
604	.Sp	670	.Sp
605	.Vb 2	671	.Vb 2
606	\& ev_ref (myloop);	672	\& ev_ref (loop);
607	\& ev_signal_stop (myloop, &exitsig);	673	\& ev_signal_stop (loop, &exitsig);
608	.Ve	674	.Ve
609	.SH "ANATOMY OF A WATCHER"	675	.SH "ANATOMY OF A WATCHER"
610	.IX Header "ANATOMY OF A WATCHER"	676	.IX Header "ANATOMY OF A WATCHER"
611	A watcher is a structure that you create and register to record your	677	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	678	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.	750	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	751	.ie n .IP """EV_CHILD""" 4
686	.el .IP "\f(CWEV_CHILD\fR" 4	752	.el .IP "\f(CWEV_CHILD\fR" 4
687	.IX Item "EV_CHILD"	753	.IX Item "EV_CHILD"
688	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.	754	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.
		755	.ie n .IP """EV_STAT""" 4
		756	.el .IP "\f(CWEV_STAT\fR" 4
		757	.IX Item "EV_STAT"
		758	The path specified in the \f(CW\(C`ev_stat\(C'\fR watcher changed its attributes somehow.
689	.ie n .IP """EV_IDLE""" 4	759	.ie n .IP """EV_IDLE""" 4
690	.el .IP "\f(CWEV_IDLE\fR" 4	760	.el .IP "\f(CWEV_IDLE\fR" 4
691	.IX Item "EV_IDLE"	761	.IX Item "EV_IDLE"
692	The \f(CW\(C`ev_idle\(C'\fR watcher has determined that you have nothing better to do.	762	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	763	.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	773	\&\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	774	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	775	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	776	(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).	777	\&\f(CW\(C`ev_loop\(C'\fR from blocking).
		778	.ie n .IP """EV_EMBED""" 4
		779	.el .IP "\f(CWEV_EMBED\fR" 4
		780	.IX Item "EV_EMBED"
		781	The embedded event loop specified in the \f(CW\(C`ev_embed\(C'\fR watcher needs attention.
		782	.ie n .IP """EV_FORK""" 4
		783	.el .IP "\f(CWEV_FORK\fR" 4
		784	.IX Item "EV_FORK"
		785	The event loop has been resumed in the child process after fork (see
		786	\&\f(CW\(C`ev_fork\(C'\fR).
708	.ie n .IP """EV_ERROR""" 4	787	.ie n .IP """EV_ERROR""" 4
709	.el .IP "\f(CWEV_ERROR\fR" 4	788	.el .IP "\f(CWEV_ERROR\fR" 4
710	.IX Item "EV_ERROR"	789	.IX Item "EV_ERROR"
711	An unspecified error has occured, the watcher has been stopped. This might	790	An unspecified error has occured, the watcher has been stopped. This might
712	happen because the watcher could not be properly started because libev	791	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	858	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	859	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	860	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	861	\&\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).	862	libev (e.g. you cnanot \f(CW\(C`free ()\(C'\fR it).
784	.IP "callback = ev_cb (ev_TYPE *watcher)" 4	863	.IP "callback ev_cb (ev_TYPE *watcher)" 4
785	.IX Item "callback = ev_cb (ev_TYPE *watcher)"	864	.IX Item "callback ev_cb (ev_TYPE *watcher)"
786	Returns the callback currently set on the watcher.	865	Returns the callback currently set on the watcher.
787	.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4	866	.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
788	.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"	867	.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
789	Change the callback. You can change the callback at virtually any time	868	Change the callback. You can change the callback at virtually any time
790	(modulo threads).	869	(modulo threads).
…		…
816	\& struct my_io w = (struct my_io )w_;	895	\& struct my_io w = (struct my_io )w_;
817	\& ...	896	\& ...
818	\& }	897	\& }
819	.Ve	898	.Ve
820	.PP	899	.PP
821	More interesting and less C\-conformant ways of catsing your callback type	900	More interesting and less C\-conformant ways of casting your callback type
822	have been omitted....	901	instead have been omitted.
		902	.PP
		903	Another common scenario is having some data structure with multiple
		904	watchers:
		905	.PP
		906	.Vb 6
		907	\& struct my_biggy
		908	\& {
		909	\& int some_data;
		910	\& ev_timer t1;
		911	\& ev_timer t2;
		912	\& }
		913	.Ve
		914	.PP
		915	In this case getting the pointer to \f(CW\(C`my_biggy\(C'\fR is a bit more complicated,
		916	you need to use \f(CW\(C`offsetof\(C'\fR:
		917	.PP
		918	.Vb 1
		919	\& #include <stddef.h>
		920	.Ve
		921	.PP
		922	.Vb 6
		923	\& static void
		924	\& t1_cb (EV_P_ struct ev_timer *w, int revents)
		925	\& {
		926	\& struct my_biggy big = (struct my_biggy *
		927	\& (((char *)w) - offsetof (struct my_biggy, t1));
		928	\& }
		929	.Ve
		930	.PP
		931	.Vb 6
		932	\& static void
		933	\& t2_cb (EV_P_ struct ev_timer *w, int revents)
		934	\& {
		935	\& struct my_biggy big = (struct my_biggy *
		936	\& (((char *)w) - offsetof (struct my_biggy, t2));
		937	\& }
		938	.Ve
823	.SH "WATCHER TYPES"	939	.SH "WATCHER TYPES"
824	.IX Header "WATCHER TYPES"	940	.IX Header "WATCHER TYPES"
825	This section describes each watcher in detail, but will not repeat	941	This section describes each watcher in detail, but will not repeat
826	information given in the last section.	942	information given in the last section. Any initialisation/set macros,
		943	functions and members specific to the watcher type are explained.
		944	.PP
		945	Members are additionally marked with either \fI[read\-only]\fR, meaning that,
		946	while the watcher is active, you can look at the member and expect some
		947	sensible content, but you must not modify it (you can modify it while the
		948	watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
		949	means you can expect it to have some sensible content while the watcher
		950	is active, but you can also modify it. Modifying it may not do something
		951	sensible or take immediate effect (or do anything at all), but libev will
		952	not crash or malfunction in any way.
827	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable?"	953	.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?"	954	.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?"	955	.IX Subsection "ev_io - is this file descriptor readable or writable?"
830	I/O watchers check whether a file descriptor is readable or writable	956	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	957	in each iteration of the event loop, or, more precisely, when reading
…		…
871	.IX Item "ev_io_set (ev_io *, int fd, int events)"	997	.IX Item "ev_io_set (ev_io *, int fd, int events)"
872	.PD	998	.PD
873	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The \f(CW\(C`fd\(C'\fR is the file descriptor to	999	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	1000	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.	1001	\&\f(CW\(C`EV_READ \| EV_WRITE\(C'\fR to receive the given events.
		1002	.IP "int fd [read\-only]" 4
		1003	.IX Item "int fd [read-only]"
		1004	The file descriptor being watched.
		1005	.IP "int events [read\-only]" 4
		1006	.IX Item "int events [read-only]"
		1007	The events being watched.
876	.PP	1008	.PP
877	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well	1009	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	1010	readable, but only once. Since it is likely line\-buffered, you could
879	attempt to read a whole line in the callback:	1011	attempt to read a whole line in the callback.
880	.PP	1012	.PP
881	.Vb 6	1013	.Vb 6
882	\& static void	1014	\& static void
883	\& stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	1015	\& stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
884	\& {	1016	\& {
…		…
939	.IP "ev_timer_again (loop)" 4	1071	.IP "ev_timer_again (loop)" 4
940	.IX Item "ev_timer_again (loop)"	1072	.IX Item "ev_timer_again (loop)"
941	This will act as if the timer timed out and restart it again if it is	1073	This will act as if the timer timed out and restart it again if it is
942	repeating. The exact semantics are:	1074	repeating. The exact semantics are:
943	.Sp	1075	.Sp
		1076	If the timer is pending, its pending status is cleared.
		1077	.Sp
944	If the timer is started but nonrepeating, stop it.	1078	If the timer is started but nonrepeating, stop it (as if it timed out).
945	.Sp	1079	.Sp
946	If the timer is repeating, either start it if necessary (with the repeat	1080	If the timer is repeating, either start it if necessary (with the
947	value), or reset the running timer to the repeat value.	1081	\&\f(CW\(C`repeat\(C'\fR value), or reset the running timer to the \f(CW\(C`repeat\(C'\fR value.
948	.Sp	1082	.Sp
949	This sounds a bit complicated, but here is a useful and typical	1083	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	1084	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	1085	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	1086	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	1087	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	1088	\&\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	1089	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.	1090	socket, you can \f(CW\(C`ev_timer_stop\(C'\fR the timer, and \f(CW\(C`ev_timer_again\(C'\fR will
		1091	automatically restart it if need be.
		1092	.Sp
		1093	That means you can ignore the \f(CW\(C`after\(C'\fR value and \f(CW\(C`ev_timer_start\(C'\fR
		1094	altogether and only ever use the \f(CW\(C`repeat\(C'\fR value and \f(CW\(C`ev_timer_again\(C'\fR:
		1095	.Sp
		1096	.Vb 8
		1097	\& ev_timer_init (timer, callback, 0., 5.);
		1098	\& ev_timer_again (loop, timer);
		1099	\& ...
		1100	\& timer->again = 17.;
		1101	\& ev_timer_again (loop, timer);
		1102	\& ...
		1103	\& timer->again = 10.;
		1104	\& ev_timer_again (loop, timer);
		1105	.Ve
		1106	.Sp
		1107	This is more slightly efficient then stopping/starting the timer each time
		1108	you want to modify its timeout value.
		1109	.IP "ev_tstamp repeat [read\-write]" 4
		1110	.IX Item "ev_tstamp repeat [read-write]"
		1111	The current \f(CW\(C`repeat\(C'\fR value. Will be used each time the watcher times out
		1112	or \f(CW\(C`ev_timer_again\(C'\fR is called and determines the next timeout (if any),
		1113	which is also when any modifications are taken into account.
957	.PP	1114	.PP
958	Example: create a timer that fires after 60 seconds.	1115	Example: Create a timer that fires after 60 seconds.
959	.PP	1116	.PP
960	.Vb 5	1117	.Vb 5
961	\& static void	1118	\& static void
962	\& one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1119	\& one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
963	\& {	1120	\& {
…		…
969	\& struct ev_timer mytimer;	1126	\& struct ev_timer mytimer;
970	\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1127	\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
971	\& ev_timer_start (loop, &mytimer);	1128	\& ev_timer_start (loop, &mytimer);
972	.Ve	1129	.Ve
973	.PP	1130	.PP
974	Example: create a timeout timer that times out after 10 seconds of	1131	Example: Create a timeout timer that times out after 10 seconds of
975	inactivity.	1132	inactivity.
976	.PP	1133	.PP
977	.Vb 5	1134	.Vb 5
978	\& static void	1135	\& static void
979	\& timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1136	\& timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
…		…
1093	.IX Item "ev_periodic_again (loop, ev_periodic *)"	1250	.IX Item "ev_periodic_again (loop, ev_periodic *)"
1094	Simply stops and restarts the periodic watcher again. This is only useful	1251	Simply stops and restarts the periodic watcher again. This is only useful
1095	when you changed some parameters or the reschedule callback would return	1252	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	1253	a different time than the last time it was called (e.g. in a crond like
1097	program when the crontabs have changed).	1254	program when the crontabs have changed).
		1255	.IP "ev_tstamp interval [read\-write]" 4
		1256	.IX Item "ev_tstamp interval [read-write]"
		1257	The current interval value. Can be modified any time, but changes only
		1258	take effect when the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being
		1259	called.
		1260	.IP "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read\-write]" 4
		1261	.IX Item "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]"
		1262	The current reschedule callback, or \f(CW0\fR, if this functionality is
		1263	switched off. Can be changed any time, but changes only take effect when
		1264	the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being called.
1098	.PP	1265	.PP
1099	Example: call a callback every hour, or, more precisely, whenever the	1266	Example: Call a callback every hour, or, more precisely, whenever the
1100	system clock is divisible by 3600. The callback invocation times have	1267	system clock is divisible by 3600. The callback invocation times have
1101	potentially a lot of jittering, but good long-term stability.	1268	potentially a lot of jittering, but good long-term stability.
1102	.PP	1269	.PP
1103	.Vb 5	1270	.Vb 5
1104	\& static void	1271	\& static void
…		…
1112	\& struct ev_periodic hourly_tick;	1279	\& struct ev_periodic hourly_tick;
1113	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1280	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1114	\& ev_periodic_start (loop, &hourly_tick);	1281	\& ev_periodic_start (loop, &hourly_tick);
1115	.Ve	1282	.Ve
1116	.PP	1283	.PP
1117	Example: the same as above, but use a reschedule callback to do it:	1284	Example: The same as above, but use a reschedule callback to do it:
1118	.PP	1285	.PP
1119	.Vb 1	1286	.Vb 1
1120	\& #include <math.h>	1287	\& #include <math.h>
1121	.Ve	1288	.Ve
1122	.PP	1289	.PP
…		…
1130	.PP	1297	.PP
1131	.Vb 1	1298	.Vb 1
1132	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1299	\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1133	.Ve	1300	.Ve
1134	.PP	1301	.PP
1135	Example: call a callback every hour, starting now:	1302	Example: Call a callback every hour, starting now:
1136	.PP	1303	.PP
1137	.Vb 4	1304	.Vb 4
1138	\& struct ev_periodic hourly_tick;	1305	\& struct ev_periodic hourly_tick;
1139	\& ev_periodic_init (&hourly_tick, clock_cb,	1306	\& ev_periodic_init (&hourly_tick, clock_cb,
1140	\& fmod (ev_now (loop), 3600.), 3600., 0);	1307	\& fmod (ev_now (loop), 3600.), 3600., 0);
…		…
1160	.IP "ev_signal_set (ev_signal *, int signum)" 4	1327	.IP "ev_signal_set (ev_signal *, int signum)" 4
1161	.IX Item "ev_signal_set (ev_signal *, int signum)"	1328	.IX Item "ev_signal_set (ev_signal *, int signum)"
1162	.PD	1329	.PD
1163	Configures the watcher to trigger on the given signal number (usually one	1330	Configures the watcher to trigger on the given signal number (usually one
1164	of the \f(CW\(C`SIGxxx\(C'\fR constants).	1331	of the \f(CW\(C`SIGxxx\(C'\fR constants).
		1332	.IP "int signum [read\-only]" 4
		1333	.IX Item "int signum [read-only]"
		1334	The signal the watcher watches out for.
1165	.ie n .Sh """ev_child"" \- watch out for process status changes"	1335	.ie n .Sh """ev_child"" \- watch out for process status changes"
1166	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"	1336	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1167	.IX Subsection "ev_child - watch out for process status changes"	1337	.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	1338	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).	1339	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	1347	\&\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	1348	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	1349	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	1350	\&\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.	1351	process causing the status change.
		1352	.IP "int pid [read\-only]" 4
		1353	.IX Item "int pid [read-only]"
		1354	The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
		1355	.IP "int rpid [read\-write]" 4
		1356	.IX Item "int rpid [read-write]"
		1357	The process id that detected a status change.
		1358	.IP "int rstatus [read\-write]" 4
		1359	.IX Item "int rstatus [read-write]"
		1360	The process exit/trace status caused by \f(CW\(C`rpid\(C'\fR (see your systems
		1361	\&\f(CW\(C`waitpid\(C'\fR and \f(CW\(C`sys/wait.h\(C'\fR documentation for details).
1182	.PP	1362	.PP
1183	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.	1363	Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1184	.PP	1364	.PP
1185	.Vb 5	1365	.Vb 5
1186	\& static void	1366	\& static void
1187	\& sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1367	\& sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1188	\& {	1368	\& {
…		…
1192	.PP	1372	.PP
1193	.Vb 3	1373	.Vb 3
1194	\& struct ev_signal signal_watcher;	1374	\& struct ev_signal signal_watcher;
1195	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1375	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1196	\& ev_signal_start (loop, &sigint_cb);	1376	\& ev_signal_start (loop, &sigint_cb);
		1377	.Ve
		1378	.ie n .Sh """ev_stat"" \- did the file attributes just change?"
		1379	.el .Sh "\f(CWev_stat\fP \- did the file attributes just change?"
		1380	.IX Subsection "ev_stat - did the file attributes just change?"
		1381	This watches a filesystem path for attribute changes. That is, it calls
		1382	\&\f(CW\(C`stat\(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed
		1383	compared to the last time, invoking the callback if it did.
		1384	.PP
		1385	The path does not need to exist: changing from \(L"path exists\(R" to \*(L"path does
		1386	not exist\(R" is a status change like any other. The condition \(L"path does
		1387	not exist\(R" is signified by the \f(CW\(C`st_nlink\*(C'\fR field being zero (which is
		1388	otherwise always forced to be at least one) and all the other fields of
		1389	the stat buffer having unspecified contents.
		1390	.PP
		1391	The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is
		1392	relative and your working directory changes, the behaviour is undefined.
		1393	.PP
		1394	Since there is no standard to do this, the portable implementation simply
		1395	calls \f(CW\(C`stat (2)\(C'\fR regularly on the path to see if it changed somehow. You
		1396	can specify a recommended polling interval for this case. If you specify
		1397	a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
		1398	unspecified default\fR value will be used (which you can expect to be around
		1399	five seconds, although this might change dynamically). Libev will also
		1400	impose a minimum interval which is currently around \f(CW0.1\fR, but thats
		1401	usually overkill.
		1402	.PP
		1403	This watcher type is not meant for massive numbers of stat watchers,
		1404	as even with OS-supported change notifications, this can be
		1405	resource\-intensive.
		1406	.PP
		1407	At the time of this writing, only the Linux inotify interface is
		1408	implemented (implementing kqueue support is left as an exercise for the
		1409	reader). Inotify will be used to give hints only and should not change the
		1410	semantics of \f(CW\(C`ev_stat\(C'\fR watchers, which means that libev sometimes needs
		1411	to fall back to regular polling again even with inotify, but changes are
		1412	usually detected immediately, and if the file exists there will be no
		1413	polling.
		1414	.IP "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)" 4
		1415	.IX Item "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)"
		1416	.PD 0
		1417	.IP "ev_stat_set (ev_stat , const char path, ev_tstamp interval)" 4
		1418	.IX Item "ev_stat_set (ev_stat , const char path, ev_tstamp interval)"
		1419	.PD
		1420	Configures the watcher to wait for status changes of the given
		1421	\&\f(CW\(C`path\(C'\fR. The \f(CW\(C`interval\(C'\fR is a hint on how quickly a change is expected to
		1422	be detected and should normally be specified as \f(CW0\fR to let libev choose
		1423	a suitable value. The memory pointed to by \f(CW\(C`path\(C'\fR must point to the same
		1424	path for as long as the watcher is active.
		1425	.Sp
		1426	The callback will be receive \f(CW\(C`EV_STAT\(C'\fR when a change was detected,
		1427	relative to the attributes at the time the watcher was started (or the
		1428	last change was detected).
		1429	.IP "ev_stat_stat (ev_stat *)" 4
		1430	.IX Item "ev_stat_stat (ev_stat *)"
		1431	Updates the stat buffer immediately with new values. If you change the
		1432	watched path in your callback, you could call this fucntion to avoid
		1433	detecting this change (while introducing a race condition). Can also be
		1434	useful simply to find out the new values.
		1435	.IP "ev_statdata attr [read\-only]" 4
		1436	.IX Item "ev_statdata attr [read-only]"
		1437	The most-recently detected attributes of the file. Although the type is of
		1438	\&\f(CW\(C`ev_statdata\(C'\fR, this is usually the (or one of the) \f(CW\(C`struct stat\(C'\fR types
		1439	suitable for your system. If the \f(CW\(C`st_nlink\(C'\fR member is \f(CW0\fR, then there
		1440	was some error while \f(CW\(C`stat\(C'\fRing the file.
		1441	.IP "ev_statdata prev [read\-only]" 4
		1442	.IX Item "ev_statdata prev [read-only]"
		1443	The previous attributes of the file. The callback gets invoked whenever
		1444	\&\f(CW\(C`prev\(C'\fR != \f(CW\(C`attr\(C'\fR.
		1445	.IP "ev_tstamp interval [read\-only]" 4
		1446	.IX Item "ev_tstamp interval [read-only]"
		1447	The specified interval.
		1448	.IP "const char *path [read\-only]" 4
		1449	.IX Item "const char *path [read-only]"
		1450	The filesystem path that is being watched.
		1451	.PP
		1452	Example: Watch \f(CW\(C`/etc/passwd\(C'\fR for attribute changes.
		1453	.PP
		1454	.Vb 15
		1455	\& static void
		1456	\& passwd_cb (struct ev_loop loop, ev_stat w, int revents)
		1457	\& {
		1458	\& /* /etc/passwd changed in some way */
		1459	\& if (w->attr.st_nlink)
		1460	\& {
		1461	\& printf ("passwd current size %ld\en", (long)w->attr.st_size);
		1462	\& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime);
		1463	\& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime);
		1464	\& }
		1465	\& else
		1466	\& /* you shalt not abuse printf for puts */
		1467	\& puts ("wow, /etc/passwd is not there, expect problems. "
		1468	\& "if this is windows, they already arrived\en");
		1469	\& }
		1470	.Ve
		1471	.PP
		1472	.Vb 2
		1473	\& ...
		1474	\& ev_stat passwd;
		1475	.Ve
		1476	.PP
		1477	.Vb 2
		1478	\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
		1479	\& ev_stat_start (loop, &passwd);
1197	.Ve	1480	.Ve
1198	.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."	1481	.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..."	1482	.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..."	1483	.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	1484	Idle watchers trigger events when there are no other events are pending
…		…
1217	.IX Item "ev_idle_init (ev_signal *, callback)"	1500	.IX Item "ev_idle_init (ev_signal *, callback)"
1218	Initialises and configures the idle watcher \- it has no parameters of any	1501	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,	1502	kind. There is a \f(CW\(C`ev_idle_set\(C'\fR macro, but using it is utterly pointless,
1220	believe me.	1503	believe me.
1221	.PP	1504	.PP
1222	Example: dynamically allocate an \f(CW\(C`ev_idle\(C'\fR, start it, and in the	1505	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.	1506	callback, free it. Also, use no error checking, as usual.
1224	.PP	1507	.PP
1225	.Vb 7	1508	.Vb 7
1226	\& static void	1509	\& static void
1227	\& idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1510	\& idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1228	\& {	1511	\& {
…		…
1295	.Vb 2	1578	.Vb 2
1296	\& static ev_io iow [nfd];	1579	\& static ev_io iow [nfd];
1297	\& static ev_timer tw;	1580	\& static ev_timer tw;
1298	.Ve	1581	.Ve
1299	.PP	1582	.PP
1300	.Vb 8	1583	.Vb 9
1301	\& static void	1584	\& static void
1302	\& io_cb (ev_loop loop, ev_io w, int revents)	1585	\& io_cb (ev_loop loop, ev_io w, int revents)
1303	\& {	1586	\& {
1304	\& // set the relevant poll flags	1587	\& // set the relevant poll flags
		1588	\& // could also call adns_processreadable etc. here
1305	\& struct pollfd fd = (struct pollfd )w->data;	1589	\& struct pollfd fd = (struct pollfd )w->data;
1306	\& if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;	1590	\& if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1307	\& if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;	1591	\& if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
1308	\& }	1592	\& }
1309	.Ve	1593	.Ve
…		…
1448	.IP "ev_embed_sweep (loop, ev_embed *)" 4	1732	.IP "ev_embed_sweep (loop, ev_embed *)" 4
1449	.IX Item "ev_embed_sweep (loop, ev_embed *)"	1733	.IX Item "ev_embed_sweep (loop, ev_embed *)"
1450	Make a single, non-blocking sweep over the embedded loop. This works	1734	Make a single, non-blocking sweep over the embedded loop. This works
1451	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most	1735	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most
1452	apropriate way for embedded loops.	1736	apropriate way for embedded loops.
		1737	.IP "struct ev_loop *loop [read\-only]" 4
		1738	.IX Item "struct ev_loop *loop [read-only]"
		1739	The embedded event loop.
		1740	.ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork"
		1741	.el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
		1742	.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
		1743	Fork watchers are called when a \f(CW\(C`fork ()\(C'\fR was detected (usually because
		1744	whoever is a good citizen cared to tell libev about it by calling
		1745	\&\f(CW\(C`ev_default_fork\(C'\fR or \f(CW\(C`ev_loop_fork\(C'\fR). The invocation is done before the
		1746	event loop blocks next and before \f(CW\(C`ev_check\(C'\fR watchers are being called,
		1747	and only in the child after the fork. If whoever good citizen calling
		1748	\&\f(CW\(C`ev_default_fork\(C'\fR cheats and calls it in the wrong process, the fork
		1749	handlers will be invoked, too, of course.
		1750	.IP "ev_fork_init (ev_signal *, callback)" 4
		1751	.IX Item "ev_fork_init (ev_signal *, callback)"
		1752	Initialises and configures the fork watcher \- it has no parameters of any
		1753	kind. There is a \f(CW\(C`ev_fork_set\(C'\fR macro, but using it is utterly pointless,
		1754	believe me.
1453	.SH "OTHER FUNCTIONS"	1755	.SH "OTHER FUNCTIONS"
1454	.IX Header "OTHER FUNCTIONS"	1756	.IX Header "OTHER FUNCTIONS"
1455	There are some other functions of possible interest. Described. Here. Now.	1757	There are some other functions of possible interest. Described. Here. Now.
1456	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4	1758	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
1457	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"	1759	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
…		…
1596	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.	1898	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.
1597	.ie n .IP "w\->sweep () ""ev::embed"" only" 4	1899	.ie n .IP "w\->sweep () ""ev::embed"" only" 4
1598	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4	1900	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
1599	.IX Item "w->sweep () ev::embed only"	1901	.IX Item "w->sweep () ev::embed only"
1600	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.	1902	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.
		1903	.ie n .IP "w\->update () ""ev::stat"" only" 4
		1904	.el .IP "w\->update () \f(CWev::stat\fR only" 4
		1905	.IX Item "w->update () ev::stat only"
		1906	Invokes \f(CW\(C`ev_stat_stat\(C'\fR.
1601	.RE	1907	.RE
1602	.RS 4	1908	.RS 4
1603	.RE	1909	.RE
1604	.PP	1910	.PP
1605	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in	1911	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
…		…
1622	\& : io (this, &myclass::io_cb),	1928	\& : io (this, &myclass::io_cb),
1623	\& idle (this, &myclass::idle_cb)	1929	\& idle (this, &myclass::idle_cb)
1624	\& {	1930	\& {
1625	\& io.start (fd, ev::READ);	1931	\& io.start (fd, ev::READ);
1626	\& }	1932	\& }
		1933	.Ve
		1934	.SH "MACRO MAGIC"
		1935	.IX Header "MACRO MAGIC"
		1936	Libev can be compiled with a variety of options, the most fundemantal is
		1937	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR. This option determines wether (most) functions and
		1938	callbacks have an initial \f(CW\(C`struct ev_loop \*(C'\fR argument.
		1939	.PP
		1940	To make it easier to write programs that cope with either variant, the
		1941	following macros are defined:
		1942	.ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4
		1943	.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
		1944	.IX Item "EV_A, EV_A_"
		1945	This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
		1946	loop argument\(R"). The \f(CW\(C`EV_A\*(C'\fR form is used when this is the sole argument,
		1947	\&\f(CW\(C`EV_A_\(C'\fR is used when other arguments are following. Example:
		1948	.Sp
		1949	.Vb 3
		1950	\& ev_unref (EV_A);
		1951	\& ev_timer_add (EV_A_ watcher);
		1952	\& ev_loop (EV_A_ 0);
		1953	.Ve
		1954	.Sp
		1955	It assumes the variable \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR is in scope,
		1956	which is often provided by the following macro.
		1957	.ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4
		1958	.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
		1959	.IX Item "EV_P, EV_P_"
		1960	This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
		1961	loop parameter\(R"). The \f(CW\(C`EV_P\*(C'\fR form is used when this is the sole parameter,
		1962	\&\f(CW\(C`EV_P_\(C'\fR is used when other parameters are following. Example:
		1963	.Sp
		1964	.Vb 2
		1965	\& // this is how ev_unref is being declared
		1966	\& static void ev_unref (EV_P);
		1967	.Ve
		1968	.Sp
		1969	.Vb 2
		1970	\& // this is how you can declare your typical callback
		1971	\& static void cb (EV_P_ ev_timer *w, int revents)
		1972	.Ve
		1973	.Sp
		1974	It declares a parameter \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR, quite
		1975	suitable for use with \f(CW\(C`EV_A\(C'\fR.
		1976	.ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4
		1977	.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
		1978	.IX Item "EV_DEFAULT, EV_DEFAULT_"
		1979	Similar to the other two macros, this gives you the value of the default
		1980	loop, if multiple loops are supported (\(L"ev loop default\(R").
		1981	.PP
		1982	Example: Declare and initialise a check watcher, working regardless of
		1983	wether multiple loops are supported or not.
		1984	.PP
		1985	.Vb 5
		1986	\& static void
		1987	\& check_cb (EV_P_ ev_timer *w, int revents)
		1988	\& {
		1989	\& ev_check_stop (EV_A_ w);
		1990	\& }
		1991	.Ve
		1992	.PP
		1993	.Vb 4
		1994	\& ev_check check;
		1995	\& ev_check_init (&check, check_cb);
		1996	\& ev_check_start (EV_DEFAULT_ &check);
		1997	\& ev_loop (EV_DEFAULT_ 0);
1627	.Ve	1998	.Ve
1628	.SH "EMBEDDING"	1999	.SH "EMBEDDING"
1629	.IX Header "EMBEDDING"	2000	.IX Header "EMBEDDING"
1630	Libev can (and often is) directly embedded into host	2001	Libev can (and often is) directly embedded into host
1631	applications. Examples of applications that embed it include the Deliantra	2002	applications. Examples of applications that embed it include the Deliantra
…		…
1811	otherwise another method will be used as fallback. This is the preferred	2182	otherwise another method will be used as fallback. This is the preferred
1812	backend for Solaris 10 systems.	2183	backend for Solaris 10 systems.
1813	.IP "\s-1EV_USE_DEVPOLL\s0" 4	2184	.IP "\s-1EV_USE_DEVPOLL\s0" 4
1814	.IX Item "EV_USE_DEVPOLL"	2185	.IX Item "EV_USE_DEVPOLL"
1815	reserved for future expansion, works like the \s-1USE\s0 symbols above.	2186	reserved for future expansion, works like the \s-1USE\s0 symbols above.
		2187	.IP "\s-1EV_USE_INOTIFY\s0" 4
		2188	.IX Item "EV_USE_INOTIFY"
		2189	If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify
		2190	interface to speed up \f(CW\(C`ev_stat\(C'\fR watchers. Its actual availability will
		2191	be detected at runtime.
1816	.IP "\s-1EV_H\s0" 4	2192	.IP "\s-1EV_H\s0" 4
1817	.IX Item "EV_H"	2193	.IX Item "EV_H"
1818	The name of the \fIev.h\fR header file used to include it. The default if	2194	The name of the \fIev.h\fR header file used to include it. The default if
1819	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This	2195	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
1820	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.	2196	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
…		…
1838	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions	2214	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
1839	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create	2215	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create
1840	additional independent event loops. Otherwise there will be no support	2216	additional independent event loops. Otherwise there will be no support
1841	for multiple event loops and there is no first event loop pointer	2217	for multiple event loops and there is no first event loop pointer
1842	argument. Instead, all functions act on the single default loop.	2218	argument. Instead, all functions act on the single default loop.
1843	.IP "\s-1EV_PERIODICS\s0" 4	2219	.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
1844	.IX Item "EV_PERIODICS"	2220	.IX Item "EV_PERIODIC_ENABLE"
1845	If undefined or defined to be \f(CW1\fR, then periodic timers are supported,	2221	If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
1846	otherwise not. This saves a few kb of code.	2222	defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
		2223	code.
		2224	.IP "\s-1EV_EMBED_ENABLE\s0" 4
		2225	.IX Item "EV_EMBED_ENABLE"
		2226	If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
		2227	defined to be \f(CW0\fR, then they are not.
		2228	.IP "\s-1EV_STAT_ENABLE\s0" 4
		2229	.IX Item "EV_STAT_ENABLE"
		2230	If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
		2231	defined to be \f(CW0\fR, then they are not.
		2232	.IP "\s-1EV_FORK_ENABLE\s0" 4
		2233	.IX Item "EV_FORK_ENABLE"
		2234	If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If
		2235	defined to be \f(CW0\fR, then they are not.
		2236	.IP "\s-1EV_MINIMAL\s0" 4
		2237	.IX Item "EV_MINIMAL"
		2238	If you need to shave off some kilobytes of code at the expense of some
		2239	speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
		2240	some inlining decisions, saves roughly 30% codesize of amd64.
		2241	.IP "\s-1EV_PID_HASHSIZE\s0" 4
		2242	.IX Item "EV_PID_HASHSIZE"
		2243	\&\f(CW\(C`ev_child\(C'\fR watchers use a small hash table to distribute workload by
		2244	pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\(C`EV_MINIMAL\(C'\fR), usually more
		2245	than enough. If you need to manage thousands of children you might want to
		2246	increase this value (\fImust\fR be a power of two).
		2247	.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
		2248	.IX Item "EV_INOTIFY_HASHSIZE"
		2249	\&\f(CW\(C`ev_staz\(C'\fR watchers use a small hash table to distribute workload by
		2250	inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\(C`EV_MINIMAL\(C'\fR),
		2251	usually more than enough. If you need to manage thousands of \f(CW\(C`ev_stat\(C'\fR
		2252	watchers you might want to increase this value (\fImust\fR be a power of
		2253	two).
1847	.IP "\s-1EV_COMMON\s0" 4	2254	.IP "\s-1EV_COMMON\s0" 4
1848	.IX Item "EV_COMMON"	2255	.IX Item "EV_COMMON"
1849	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining	2256	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining
1850	this macro to a something else you can include more and other types of	2257	this macro to a something else you can include more and other types of
1851	members. You have to define it each time you include one of the files,	2258	members. You have to define it each time you include one of the files,
…		…
1900	.Sp	2307	.Sp
1901	.Vb 2	2308	.Vb 2
1902	\& #include "ev_cpp.h"	2309	\& #include "ev_cpp.h"
1903	\& #include "ev.c"	2310	\& #include "ev.c"
1904	.Ve	2311	.Ve
		2312	.SH "COMPLEXITIES"
		2313	.IX Header "COMPLEXITIES"
		2314	In this section the complexities of (many of) the algorithms used inside
		2315	libev will be explained. For complexity discussions about backends see the
		2316	documentation for \f(CW\(C`ev_default_init\(C'\fR.
		2317	.RS 4
		2318	.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
		2319	.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
		2320	.PD 0
		2321	.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4
		2322	.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
		2323	.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
		2324	.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
		2325	.IP "Stopping check/prepare/idle watchers: O(1)" 4
		2326	.IX Item "Stopping check/prepare/idle watchers: O(1)"
		2327	.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
		2328	.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"
		2329	.IP "Finding the next timer per loop iteration: O(1)" 4
		2330	.IX Item "Finding the next timer per loop iteration: O(1)"
		2331	.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
		2332	.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
		2333	.IP "Activating one watcher: O(1)" 4
		2334	.IX Item "Activating one watcher: O(1)"
		2335	.RE
		2336	.RS 4
		2337	.PD
1905	.SH "AUTHOR"	2338	.SH "AUTHOR"
1906	.IX Header "AUTHOR"	2339	.IX Header "AUTHOR"
1907	Marc Lehmann <libev@schmorp.de>.	2340	Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.3 (file contents): Revision 1.20 by root, Mon Nov 26 09:52:14 2007 UTC vs. Revision 1.34 by root, Thu Nov 29 12:21:21 2007 UTC

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Revision 1.20 by root, Mon Nov 26 09:52:14 2007 UTC vs.
Revision 1.34 by root, Thu Nov 29 12:21:21 2007 UTC