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

Comparing libev/ev.3 (file contents):
Revision 1.11 by root, Sat Nov 24 07:14:26 2007 UTC vs.
Revision 1.27 by root, Tue Nov 27 20:15:01 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 "2007-11-27" "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 2
		138	\& /* this is the only header you need */
138	\& #include <ev.h>	139	\& #include <ev.h>
		140	.Ve
		141	.PP
		142	.Vb 3
		143	\& /* what follows is a fully working example program */
		144	\& ev_io stdin_watcher;
		145	\& ev_timer timeout_watcher;
		146	.Ve
		147	.PP
		148	.Vb 8
		149	\& /* called when data readable on stdin */
		150	\& static void
		151	\& stdin_cb (EV_P_ struct ev_io *w, int revents)
		152	\& {
		153	\& /* puts ("stdin ready"); */
		154	\& ev_io_stop (EV_A_ w); /* just a syntax example */
		155	\& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */
		156	\& }
		157	.Ve
		158	.PP
		159	.Vb 6
		160	\& static void
		161	\& timeout_cb (EV_P_ struct ev_timer *w, int revents)
		162	\& {
		163	\& /* puts ("timeout"); */
		164	\& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */
		165	\& }
		166	.Ve
		167	.PP
		168	.Vb 4
		169	\& int
		170	\& main (void)
		171	\& {
		172	\& struct ev_loop *loop = ev_default_loop (0);
		173	.Ve
		174	.PP
		175	.Vb 3
		176	\& /* initialise an io watcher, then start it */
		177	\& ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
		178	\& ev_io_start (loop, &stdin_watcher);
		179	.Ve
		180	.PP
		181	.Vb 3
		182	\& /* simple non-repeating 5.5 second timeout */
		183	\& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
		184	\& ev_timer_start (loop, &timeout_watcher);
		185	.Ve
		186	.PP
		187	.Vb 2
		188	\& /* loop till timeout or data ready */
		189	\& ev_loop (loop, 0);
		190	.Ve
		191	.PP
		192	.Vb 2
		193	\& return 0;
		194	\& }
139	.Ve	195	.Ve
140	.SH "DESCRIPTION"	196	.SH "DESCRIPTION"
141	.IX Header "DESCRIPTION"	197	.IX Header "DESCRIPTION"
142	Libev is an event loop: you register interest in certain events (such as a	198	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	199	file descriptor being readable or a timeout occuring), and it will manage
…		…
240	might be supported on the current system, you would need to look at	296	might be supported on the current system, you would need to look at
241	\&\f(CW\(C`ev_embeddable_backends () & ev_supported_backends ()\(C'\fR, likewise for	297	\&\f(CW\(C`ev_embeddable_backends () & ev_supported_backends ()\(C'\fR, likewise for
242	recommended ones.	298	recommended ones.
243	.Sp	299	.Sp
244	See the description of \f(CW\(C`ev_embed\(C'\fR watchers for more info.	300	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	301	.IP "ev_set_allocator (void (cb)(void *ptr, size_t size))" 4
246	.IX Item "ev_set_allocator (void (cb)(void *ptr, long size))"	302	.IX Item "ev_set_allocator (void (cb)(void *ptr, size_t size))"
247	Sets the allocation function to use (the prototype is similar to the	303	Sets the allocation function to use (the prototype and semantics are
248	realloc C function, the semantics are identical). It is used to allocate	304	identical to the realloc C function). It is used to allocate and free
249	and free memory (no surprises here). If it returns zero when memory	305	memory (no surprises here). If it returns zero when memory needs to be
250	needs to be allocated, the library might abort or take some potentially	306	allocated, the library might abort or take some potentially destructive
251	destructive action. The default is your system realloc function.	307	action. The default is your system realloc function.
252	.Sp	308	.Sp
253	You could override this function in high-availability programs to, say,	309	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,	310	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.	311	or even to sleep a while and retry until some memory is available.
256	.Sp	312	.Sp
257	Example: replace the libev allocator with one that waits a bit and then	313	Example: replace the libev allocator with one that waits a bit and then
258	retries: better than mine).	314	retries: better than mine).
259	.Sp	315	.Sp
260	.Vb 6	316	.Vb 6
261	\& static void *	317	\& static void *
262	\& persistent_realloc (void *ptr, long size)	318	\& persistent_realloc (void *ptr, size_t size)
263	\& {	319	\& {
264	\& for (;;)	320	\& for (;;)
265	\& {	321	\& {
266	\& void *newptr = realloc (ptr, size);	322	\& void *newptr = realloc (ptr, size);
267	.Ve	323	.Ve
…		…
458	\& fatal ("no epoll found here, maybe it hides under your chair");	514	\& fatal ("no epoll found here, maybe it hides under your chair");
459	.Ve	515	.Ve
460	.IP "ev_default_destroy ()" 4	516	.IP "ev_default_destroy ()" 4
461	.IX Item "ev_default_destroy ()"	517	.IX Item "ev_default_destroy ()"
462	Destroys the default loop again (frees all memory and kernel state	518	Destroys the default loop again (frees all memory and kernel state
463	etc.). This stops all registered event watchers (by not touching them in	519	etc.). None of the active event watchers will be stopped in the normal
464	any way whatsoever, although you cannot rely on this :).	520	sense, so e.g. \f(CW\(C`ev_is_active\(C'\fR might still return true. It is your
		521	responsibility to either stop all watchers cleanly yoursef \fIbefore\fR
		522	calling this function, or cope with the fact afterwards (which is usually
		523	the easiest thing, youc na just ignore the watchers and/or \f(CW\(C`free ()\(C'\fR them
		524	for example).
465	.IP "ev_loop_destroy (loop)" 4	525	.IP "ev_loop_destroy (loop)" 4
466	.IX Item "ev_loop_destroy (loop)"	526	.IX Item "ev_loop_destroy (loop)"
467	Like \f(CW\(C`ev_default_destroy\(C'\fR, but destroys an event loop created by an	527	Like \f(CW\(C`ev_default_destroy\(C'\fR, but destroys an event loop created by an
468	earlier call to \f(CW\(C`ev_loop_new\(C'\fR.	528	earlier call to \f(CW\(C`ev_loop_new\(C'\fR.
469	.IP "ev_default_fork ()" 4	529	.IP "ev_default_fork ()" 4
…		…
680	The signal specified in the \f(CW\(C`ev_signal\(C'\fR watcher has been received by a thread.	740	The signal specified in the \f(CW\(C`ev_signal\(C'\fR watcher has been received by a thread.
681	.ie n .IP """EV_CHILD""" 4	741	.ie n .IP """EV_CHILD""" 4
682	.el .IP "\f(CWEV_CHILD\fR" 4	742	.el .IP "\f(CWEV_CHILD\fR" 4
683	.IX Item "EV_CHILD"	743	.IX Item "EV_CHILD"
684	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.	744	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.
		745	.ie n .IP """EV_STAT""" 4
		746	.el .IP "\f(CWEV_STAT\fR" 4
		747	.IX Item "EV_STAT"
		748	The path specified in the \f(CW\(C`ev_stat\(C'\fR watcher changed its attributes somehow.
685	.ie n .IP """EV_IDLE""" 4	749	.ie n .IP """EV_IDLE""" 4
686	.el .IP "\f(CWEV_IDLE\fR" 4	750	.el .IP "\f(CWEV_IDLE\fR" 4
687	.IX Item "EV_IDLE"	751	.IX Item "EV_IDLE"
688	The \f(CW\(C`ev_idle\(C'\fR watcher has determined that you have nothing better to do.	752	The \f(CW\(C`ev_idle\(C'\fR watcher has determined that you have nothing better to do.
689	.ie n .IP """EV_PREPARE""" 4	753	.ie n .IP """EV_PREPARE""" 4
…		…
699	\&\f(CW\(C`ev_loop\(C'\fR has gathered them, but before it invokes any callbacks for any	763	\&\f(CW\(C`ev_loop\(C'\fR has gathered them, but before it invokes any callbacks for any
700	received events. Callbacks of both watcher types can start and stop as	764	received events. Callbacks of both watcher types can start and stop as
701	many watchers as they want, and all of them will be taken into account	765	many watchers as they want, and all of them will be taken into account
702	(for example, a \f(CW\(C`ev_prepare\(C'\fR watcher might start an idle watcher to keep	766	(for example, a \f(CW\(C`ev_prepare\(C'\fR watcher might start an idle watcher to keep
703	\&\f(CW\(C`ev_loop\(C'\fR from blocking).	767	\&\f(CW\(C`ev_loop\(C'\fR from blocking).
		768	.ie n .IP """EV_EMBED""" 4
		769	.el .IP "\f(CWEV_EMBED\fR" 4
		770	.IX Item "EV_EMBED"
		771	The embedded event loop specified in the \f(CW\(C`ev_embed\(C'\fR watcher needs attention.
		772	.ie n .IP """EV_FORK""" 4
		773	.el .IP "\f(CWEV_FORK\fR" 4
		774	.IX Item "EV_FORK"
		775	The event loop has been resumed in the child process after fork (see
		776	\&\f(CW\(C`ev_fork\(C'\fR).
704	.ie n .IP """EV_ERROR""" 4	777	.ie n .IP """EV_ERROR""" 4
705	.el .IP "\f(CWEV_ERROR\fR" 4	778	.el .IP "\f(CWEV_ERROR\fR" 4
706	.IX Item "EV_ERROR"	779	.IX Item "EV_ERROR"
707	An unspecified error has occured, the watcher has been stopped. This might	780	An unspecified error has occured, the watcher has been stopped. This might
708	happen because the watcher could not be properly started because libev	781	happen because the watcher could not be properly started because libev
…		…
713	Libev will usually signal a few \(L"dummy\(R" events together with an error,	786	Libev will usually signal a few \(L"dummy\(R" events together with an error,
714	for example it might indicate that a fd is readable or writable, and if	787	for example it might indicate that a fd is readable or writable, and if
715	your callbacks is well-written it can just attempt the operation and cope	788	your callbacks is well-written it can just attempt the operation and cope
716	with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded	789	with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded
717	programs, though, so beware.	790	programs, though, so beware.
718	.Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"	791	.Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"
719	.IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS"	792	.IX Subsection "GENERIC WATCHER FUNCTIONS"
720	In the following description, \f(CW\(C`TYPE\(C'\fR stands for the watcher type,	793	In the following description, \f(CW\(C`TYPE\(C'\fR stands for the watcher type,
721	e.g. \f(CW\(C`timer\(C'\fR for \f(CW\(C`ev_timer\(C'\fR watchers and \f(CW\(C`io\(C'\fR for \f(CW\(C`ev_io\(C'\fR watchers.	794	e.g. \f(CW\(C`timer\(C'\fR for \f(CW\(C`ev_timer\(C'\fR watchers and \f(CW\(C`io\(C'\fR for \f(CW\(C`ev_io\(C'\fR watchers.
722	.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4	795	.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
723	.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4	796	.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4
724	.IX Item "ev_init (ev_TYPE *watcher, callback)"	797	.IX Item "ev_init (ev_TYPE *watcher, callback)"
…		…
730	which rolls both calls into one.	803	which rolls both calls into one.
731	.Sp	804	.Sp
732	You can reinitialise a watcher at any time as long as it has been stopped	805	You can reinitialise a watcher at any time as long as it has been stopped
733	(or never started) and there are no pending events outstanding.	806	(or never started) and there are no pending events outstanding.
734	.Sp	807	.Sp
735	The callbakc is always of type \f(CW\(C`void ()(ev_loop loop, ev_TYPE watcher,	808	The callback is always of type \f(CW\(C`void ()(ev_loop loop, ev_TYPE watcher,
736	int revents)\*(C'\fR.	809	int revents)\*(C'\fR.
737	.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4	810	.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4
738	.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4	811	.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4
739	.IX Item "ev_TYPE_set (ev_TYPE *, [args])"	812	.IX Item "ev_TYPE_set (ev_TYPE *, [args])"
740	This macro initialises the type-specific parts of a watcher. You need to	813	This macro initialises the type-specific parts of a watcher. You need to
…		…
817	More interesting and less C\-conformant ways of catsing your callback type	890	More interesting and less C\-conformant ways of catsing your callback type
818	have been omitted....	891	have been omitted....
819	.SH "WATCHER TYPES"	892	.SH "WATCHER TYPES"
820	.IX Header "WATCHER TYPES"	893	.IX Header "WATCHER TYPES"
821	This section describes each watcher in detail, but will not repeat	894	This section describes each watcher in detail, but will not repeat
822	information given in the last section.	895	information given in the last section. Any initialisation/set macros,
		896	functions and members specific to the watcher type are explained.
		897	.PP
		898	Members are additionally marked with either \fI[read\-only]\fR, meaning that,
		899	while the watcher is active, you can look at the member and expect some
		900	sensible content, but you must not modify it (you can modify it while the
		901	watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
		902	means you can expect it to have some sensible content while the watcher
		903	is active, but you can also modify it. Modifying it may not do something
		904	sensible or take immediate effect (or do anything at all), but libev will
		905	not crash or malfunction in any way.
823	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable"	906	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable?"
824	.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable"	907	.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?"
825	.IX Subsection "ev_io - is this file descriptor readable or writable"	908	.IX Subsection "ev_io - is this file descriptor readable or writable?"
826	I/O watchers check whether a file descriptor is readable or writable	909	I/O watchers check whether a file descriptor is readable or writable
827	in each iteration of the event loop (This behaviour is called	910	in each iteration of the event loop, or, more precisely, when reading
828	level-triggering because you keep receiving events as long as the	911	would not block the process and writing would at least be able to write
829	condition persists. Remember you can stop the watcher if you don't want to	912	some data. This behaviour is called level-triggering because you keep
830	act on the event and neither want to receive future events).	913	receiving events as long as the condition persists. Remember you can stop
		914	the watcher if you don't want to act on the event and neither want to
		915	receive future events.
831	.PP	916	.PP
832	In general you can register as many read and/or write event watchers per	917	In general you can register as many read and/or write event watchers per
833	fd as you want (as long as you don't confuse yourself). Setting all file	918	fd as you want (as long as you don't confuse yourself). Setting all file
834	descriptors to non-blocking mode is also usually a good idea (but not	919	descriptors to non-blocking mode is also usually a good idea (but not
835	required if you know what you are doing).	920	required if you know what you are doing).
836	.PP	921	.PP
837	You have to be careful with dup'ed file descriptors, though. Some backends	922	You have to be careful with dup'ed file descriptors, though. Some backends
838	(the linux epoll backend is a notable example) cannot handle dup'ed file	923	(the linux epoll backend is a notable example) cannot handle dup'ed file
839	descriptors correctly if you register interest in two or more fds pointing	924	descriptors correctly if you register interest in two or more fds pointing
840	to the same underlying file/socket etc. description (that is, they share	925	to the same underlying file/socket/etc. description (that is, they share
841	the same underlying \(L"file open\(R").	926	the same underlying \(L"file open\(R").
842	.PP	927	.PP
843	If you must do this, then force the use of a known-to-be-good backend	928	If you must do this, then force the use of a known-to-be-good backend
844	(at the time of this writing, this includes only \f(CW\(C`EVBACKEND_SELECT\(C'\fR and	929	(at the time of this writing, this includes only \f(CW\(C`EVBACKEND_SELECT\(C'\fR and
845	\&\f(CW\(C`EVBACKEND_POLL\(C'\fR).	930	\&\f(CW\(C`EVBACKEND_POLL\(C'\fR).
		931	.PP
		932	Another thing you have to watch out for is that it is quite easy to
		933	receive \(L"spurious\(R" readyness notifications, that is your callback might
		934	be called with \f(CW\(C`EV_READ\(C'\fR but a subsequent \f(CW\(C`read\(C'\fR(2) will actually block
		935	because there is no data. Not only are some backends known to create a
		936	lot of those (for example solaris ports), it is very easy to get into
		937	this situation even with a relatively standard program structure. Thus
		938	it is best to always use non-blocking I/O: An extra \f(CW\(C`read\(C'\fR(2) returning
		939	\&\f(CW\(C`EAGAIN\(C'\fR is far preferable to a program hanging until some data arrives.
		940	.PP
		941	If you cannot run the fd in non-blocking mode (for example you should not
		942	play around with an Xlib connection), then you have to seperately re-test
		943	wether a file descriptor is really ready with a known-to-be good interface
		944	such as poll (fortunately in our Xlib example, Xlib already does this on
		945	its own, so its quite safe to use).
846	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4	946	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
847	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"	947	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
848	.PD 0	948	.PD 0
849	.IP "ev_io_set (ev_io *, int fd, int events)" 4	949	.IP "ev_io_set (ev_io *, int fd, int events)" 4
850	.IX Item "ev_io_set (ev_io *, int fd, int events)"	950	.IX Item "ev_io_set (ev_io *, int fd, int events)"
851	.PD	951	.PD
852	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The fd is the file descriptor to rceeive	952	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The \f(CW\(C`fd\(C'\fR is the file descriptor to
853	events for and events is either \f(CW\(C`EV_READ\(C'\fR, \f(CW\(C`EV_WRITE\(C'\fR or \f(CW\*(C`EV_READ \|	953	rceeive events for and events is either \f(CW\(C`EV_READ\(C'\fR, \f(CW\(C`EV_WRITE\(C'\fR or
854	EV_WRITE\*(C'\fR to receive the given events.	954	\&\f(CW\(C`EV_READ \| EV_WRITE\(C'\fR to receive the given events.
855	.Sp	955	.IP "int fd [read\-only]" 4
856	Please note that most of the more scalable backend mechanisms (for example	956	.IX Item "int fd [read-only]"
857	epoll and solaris ports) can result in spurious readyness notifications	957	The file descriptor being watched.
858	for file descriptors, so you practically need to use non-blocking I/O (and	958	.IP "int events [read\-only]" 4
859	treat callback invocation as hint only), or retest separately with a safe	959	.IX Item "int events [read-only]"
860	interface before doing I/O (XLib can do this), or force the use of either	960	The events being watched.
861	\&\f(CW\(C`EVBACKEND_SELECT\(C'\fR or \f(CW\(C`EVBACKEND_POLL\(C'\fR, which don't suffer from this
862	problem. Also note that it is quite easy to have your callback invoked
863	when the readyness condition is no longer valid even when employing
864	typical ways of handling events, so its a good idea to use non-blocking
865	I/O unconditionally.
866	.PP	961	.PP
867	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well	962	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well
868	readable, but only once. Since it is likely line\-buffered, you could	963	readable, but only once. Since it is likely line\-buffered, you could
869	attempt to read a whole line in the callback:	964	attempt to read a whole line in the callback:
870	.PP	965	.PP
…		…
883	\& struct ev_io stdin_readable;	978	\& struct ev_io stdin_readable;
884	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	979	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
885	\& ev_io_start (loop, &stdin_readable);	980	\& ev_io_start (loop, &stdin_readable);
886	\& ev_loop (loop, 0);	981	\& ev_loop (loop, 0);
887	.Ve	982	.Ve
888	.ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts"	983	.ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts"
889	.el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts"	984	.el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts"
890	.IX Subsection "ev_timer - relative and optionally recurring timeouts"	985	.IX Subsection "ev_timer - relative and optionally repeating timeouts"
891	Timer watchers are simple relative timers that generate an event after a	986	Timer watchers are simple relative timers that generate an event after a
892	given time, and optionally repeating in regular intervals after that.	987	given time, and optionally repeating in regular intervals after that.
893	.PP	988	.PP
894	The timers are based on real time, that is, if you register an event that	989	The timers are based on real time, that is, if you register an event that
895	times out after an hour and you reset your system clock to last years	990	times out after an hour and you reset your system clock to last years
…		…
935	.Sp	1030	.Sp
936	If the timer is repeating, either start it if necessary (with the repeat	1031	If the timer is repeating, either start it if necessary (with the repeat
937	value), or reset the running timer to the repeat value.	1032	value), or reset the running timer to the repeat value.
938	.Sp	1033	.Sp
939	This sounds a bit complicated, but here is a useful and typical	1034	This sounds a bit complicated, but here is a useful and typical
940	example: Imagine you have a tcp connection and you want a so-called idle	1035	example: Imagine you have a tcp connection and you want a so-called
941	timeout, that is, you want to be called when there have been, say, 60	1036	idle timeout, that is, you want to be called when there have been,
942	seconds of inactivity on the socket. The easiest way to do this is to	1037	say, 60 seconds of inactivity on the socket. The easiest way to do
943	configure an \f(CW\(C`ev_timer\(C'\fR with after=repeat=60 and calling ev_timer_again each	1038	this is to configure an \f(CW\(C`ev_timer\(C'\fR with \f(CW\(C`after\(C'\fR=\f(CW\(C`repeat\(C'\fR=\f(CW60\fR and calling
944	time you successfully read or write some data. If you go into an idle	1039	\&\f(CW\(C`ev_timer_again\(C'\fR each time you successfully read or write some data. If
945	state where you do not expect data to travel on the socket, you can stop	1040	you go into an idle state where you do not expect data to travel on the
946	the timer, and again will automatically restart it if need be.	1041	socket, you can stop the timer, and again will automatically restart it if
		1042	need be.
		1043	.Sp
		1044	You can also ignore the \f(CW\(C`after\(C'\fR value and \f(CW\(C`ev_timer_start\(C'\fR altogether
		1045	and only ever use the \f(CW\(C`repeat\(C'\fR value:
		1046	.Sp
		1047	.Vb 8
		1048	\& ev_timer_init (timer, callback, 0., 5.);
		1049	\& ev_timer_again (loop, timer);
		1050	\& ...
		1051	\& timer->again = 17.;
		1052	\& ev_timer_again (loop, timer);
		1053	\& ...
		1054	\& timer->again = 10.;
		1055	\& ev_timer_again (loop, timer);
		1056	.Ve
		1057	.Sp
		1058	This is more efficient then stopping/starting the timer eahc time you want
		1059	to modify its timeout value.
		1060	.IP "ev_tstamp repeat [read\-write]" 4
		1061	.IX Item "ev_tstamp repeat [read-write]"
		1062	The current \f(CW\(C`repeat\(C'\fR value. Will be used each time the watcher times out
		1063	or \f(CW\(C`ev_timer_again\(C'\fR is called and determines the next timeout (if any),
		1064	which is also when any modifications are taken into account.
947	.PP	1065	.PP
948	Example: create a timer that fires after 60 seconds.	1066	Example: create a timer that fires after 60 seconds.
949	.PP	1067	.PP
950	.Vb 5	1068	.Vb 5
951	\& static void	1069	\& static void
…		…
982	.Vb 3	1100	.Vb 3
983	\& // and in some piece of code that gets executed on any "activity":	1101	\& // and in some piece of code that gets executed on any "activity":
984	\& // reset the timeout to start ticking again at 10 seconds	1102	\& // reset the timeout to start ticking again at 10 seconds
985	\& ev_timer_again (&mytimer);	1103	\& ev_timer_again (&mytimer);
986	.Ve	1104	.Ve
987	.ie n .Sh """ev_periodic"" \- to cron or not to cron"	1105	.ie n .Sh """ev_periodic"" \- to cron or not to cron?"
988	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron"	1106	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?"
989	.IX Subsection "ev_periodic - to cron or not to cron"	1107	.IX Subsection "ev_periodic - to cron or not to cron?"
990	Periodic watchers are also timers of a kind, but they are very versatile	1108	Periodic watchers are also timers of a kind, but they are very versatile
991	(and unfortunately a bit complex).	1109	(and unfortunately a bit complex).
992	.PP	1110	.PP
993	Unlike \f(CW\(C`ev_timer\(C'\fR's, they are not based on real time (or relative time)	1111	Unlike \f(CW\(C`ev_timer\(C'\fR's, they are not based on real time (or relative time)
994	but on wallclock time (absolute time). You can tell a periodic watcher	1112	but on wallclock time (absolute time). You can tell a periodic watcher
995	to trigger \(L"at\(R" some specific point in time. For example, if you tell a	1113	to trigger \(L"at\(R" some specific point in time. For example, if you tell a
996	periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now ()	1114	periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now ()
997	+ 10.>) and then reset your system clock to the last year, then it will	1115	+ 10.\*(C'\fR) and then reset your system clock to the last year, then it will
998	take a year to trigger the event (unlike an \f(CW\(C`ev_timer\(C'\fR, which would trigger	1116	take a year to trigger the event (unlike an \f(CW\(C`ev_timer\(C'\fR, which would trigger
999	roughly 10 seconds later and of course not if you reset your system time	1117	roughly 10 seconds later and of course not if you reset your system time
1000	again).	1118	again).
1001	.PP	1119	.PP
1002	They can also be used to implement vastly more complex timers, such as	1120	They can also be used to implement vastly more complex timers, such as
…		…
1083	.IX Item "ev_periodic_again (loop, ev_periodic *)"	1201	.IX Item "ev_periodic_again (loop, ev_periodic *)"
1084	Simply stops and restarts the periodic watcher again. This is only useful	1202	Simply stops and restarts the periodic watcher again. This is only useful
1085	when you changed some parameters or the reschedule callback would return	1203	when you changed some parameters or the reschedule callback would return
1086	a different time than the last time it was called (e.g. in a crond like	1204	a different time than the last time it was called (e.g. in a crond like
1087	program when the crontabs have changed).	1205	program when the crontabs have changed).
		1206	.IP "ev_tstamp interval [read\-write]" 4
		1207	.IX Item "ev_tstamp interval [read-write]"
		1208	The current interval value. Can be modified any time, but changes only
		1209	take effect when the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being
		1210	called.
		1211	.IP "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read\-write]" 4
		1212	.IX Item "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]"
		1213	The current reschedule callback, or \f(CW0\fR, if this functionality is
		1214	switched off. Can be changed any time, but changes only take effect when
		1215	the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being called.
1088	.PP	1216	.PP
1089	Example: call a callback every hour, or, more precisely, whenever the	1217	Example: call a callback every hour, or, more precisely, whenever the
1090	system clock is divisible by 3600. The callback invocation times have	1218	system clock is divisible by 3600. The callback invocation times have
1091	potentially a lot of jittering, but good long-term stability.	1219	potentially a lot of jittering, but good long-term stability.
1092	.PP	1220	.PP
…		…
1128	\& struct ev_periodic hourly_tick;	1256	\& struct ev_periodic hourly_tick;
1129	\& ev_periodic_init (&hourly_tick, clock_cb,	1257	\& ev_periodic_init (&hourly_tick, clock_cb,
1130	\& fmod (ev_now (loop), 3600.), 3600., 0);	1258	\& fmod (ev_now (loop), 3600.), 3600., 0);
1131	\& ev_periodic_start (loop, &hourly_tick);	1259	\& ev_periodic_start (loop, &hourly_tick);
1132	.Ve	1260	.Ve
1133	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled"	1261	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!"
1134	.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled"	1262	.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!"
1135	.IX Subsection "ev_signal - signal me when a signal gets signalled"	1263	.IX Subsection "ev_signal - signal me when a signal gets signalled!"
1136	Signal watchers will trigger an event when the process receives a specific	1264	Signal watchers will trigger an event when the process receives a specific
1137	signal one or more times. Even though signals are very asynchronous, libev	1265	signal one or more times. Even though signals are very asynchronous, libev
1138	will try it's best to deliver signals synchronously, i.e. as part of the	1266	will try it's best to deliver signals synchronously, i.e. as part of the
1139	normal event processing, like any other event.	1267	normal event processing, like any other event.
1140	.PP	1268	.PP
…		…
1150	.IP "ev_signal_set (ev_signal *, int signum)" 4	1278	.IP "ev_signal_set (ev_signal *, int signum)" 4
1151	.IX Item "ev_signal_set (ev_signal *, int signum)"	1279	.IX Item "ev_signal_set (ev_signal *, int signum)"
1152	.PD	1280	.PD
1153	Configures the watcher to trigger on the given signal number (usually one	1281	Configures the watcher to trigger on the given signal number (usually one
1154	of the \f(CW\(C`SIGxxx\(C'\fR constants).	1282	of the \f(CW\(C`SIGxxx\(C'\fR constants).
		1283	.IP "int signum [read\-only]" 4
		1284	.IX Item "int signum [read-only]"
		1285	The signal the watcher watches out for.
1155	.ie n .Sh """ev_child"" \- wait for pid status changes"	1286	.ie n .Sh """ev_child"" \- watch out for process status changes"
1156	.el .Sh "\f(CWev_child\fP \- wait for pid status changes"	1287	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1157	.IX Subsection "ev_child - wait for pid status changes"	1288	.IX Subsection "ev_child - watch out for process status changes"
1158	Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to	1289	Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
1159	some child status changes (most typically when a child of yours dies).	1290	some child status changes (most typically when a child of yours dies).
1160	.IP "ev_child_init (ev_child *, callback, int pid)" 4	1291	.IP "ev_child_init (ev_child *, callback, int pid)" 4
1161	.IX Item "ev_child_init (ev_child *, callback, int pid)"	1292	.IX Item "ev_child_init (ev_child *, callback, int pid)"
1162	.PD 0	1293	.PD 0
…		…
1167	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look	1298	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look
1168	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see	1299	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see
1169	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems	1300	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems
1170	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the	1301	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the
1171	process causing the status change.	1302	process causing the status change.
		1303	.IP "int pid [read\-only]" 4
		1304	.IX Item "int pid [read-only]"
		1305	The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
		1306	.IP "int rpid [read\-write]" 4
		1307	.IX Item "int rpid [read-write]"
		1308	The process id that detected a status change.
		1309	.IP "int rstatus [read\-write]" 4
		1310	.IX Item "int rstatus [read-write]"
		1311	The process exit/trace status caused by \f(CW\(C`rpid\(C'\fR (see your systems
		1312	\&\f(CW\(C`waitpid\(C'\fR and \f(CW\(C`sys/wait.h\(C'\fR documentation for details).
1172	.PP	1313	.PP
1173	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.	1314	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1174	.PP	1315	.PP
1175	.Vb 5	1316	.Vb 5
1176	\& static void	1317	\& static void
…		…
1183	.Vb 3	1324	.Vb 3
1184	\& struct ev_signal signal_watcher;	1325	\& struct ev_signal signal_watcher;
1185	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1326	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1186	\& ev_signal_start (loop, &sigint_cb);	1327	\& ev_signal_start (loop, &sigint_cb);
1187	.Ve	1328	.Ve
		1329	.ie n .Sh """ev_stat"" \- did the file attributes just change?"
		1330	.el .Sh "\f(CWev_stat\fP \- did the file attributes just change?"
		1331	.IX Subsection "ev_stat - did the file attributes just change?"
		1332	This watches a filesystem path for attribute changes. That is, it calls
		1333	\&\f(CW\(C`stat\(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed
		1334	compared to the last time, invoking the callback if it did.
		1335	.PP
		1336	The path does not need to exist: changing from \(L"path exists\(R" to \*(L"path does
		1337	not exist\(R" is a status change like any other. The condition \(L"path does
		1338	not exist\(R" is signified by the \f(CW\(C`st_nlink\*(C'\fR field being zero (which is
		1339	otherwise always forced to be at least one) and all the other fields of
		1340	the stat buffer having unspecified contents.
		1341	.PP
		1342	Since there is no standard to do this, the portable implementation simply
		1343	calls \f(CW\(C`stat (2)\(C'\fR regulalry on the path to see if it changed somehow. You
		1344	can specify a recommended polling interval for this case. If you specify
		1345	a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
		1346	unspecified default\fR value will be used (which you can expect to be around
		1347	five seconds, although this might change dynamically). Libev will also
		1348	impose a minimum interval which is currently around \f(CW0.1\fR, but thats
		1349	usually overkill.
		1350	.PP
		1351	This watcher type is not meant for massive numbers of stat watchers,
		1352	as even with OS-supported change notifications, this can be
		1353	resource\-intensive.
		1354	.PP
		1355	At the time of this writing, no specific \s-1OS\s0 backends are implemented, but
		1356	if demand increases, at least a kqueue and inotify backend will be added.
		1357	.IP "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)" 4
		1358	.IX Item "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)"
		1359	.PD 0
		1360	.IP "ev_stat_set (ev_stat , const char path, ev_tstamp interval)" 4
		1361	.IX Item "ev_stat_set (ev_stat , const char path, ev_tstamp interval)"
		1362	.PD
		1363	Configures the watcher to wait for status changes of the given
		1364	\&\f(CW\(C`path\(C'\fR. The \f(CW\(C`interval\(C'\fR is a hint on how quickly a change is expected to
		1365	be detected and should normally be specified as \f(CW0\fR to let libev choose
		1366	a suitable value. The memory pointed to by \f(CW\(C`path\(C'\fR must point to the same
		1367	path for as long as the watcher is active.
		1368	.Sp
		1369	The callback will be receive \f(CW\(C`EV_STAT\(C'\fR when a change was detected,
		1370	relative to the attributes at the time the watcher was started (or the
		1371	last change was detected).
		1372	.IP "ev_stat_stat (ev_stat *)" 4
		1373	.IX Item "ev_stat_stat (ev_stat *)"
		1374	Updates the stat buffer immediately with new values. If you change the
		1375	watched path in your callback, you could call this fucntion to avoid
		1376	detecting this change (while introducing a race condition). Can also be
		1377	useful simply to find out the new values.
		1378	.IP "ev_statdata attr [read\-only]" 4
		1379	.IX Item "ev_statdata attr [read-only]"
		1380	The most-recently detected attributes of the file. Although the type is of
		1381	\&\f(CW\(C`ev_statdata\(C'\fR, this is usually the (or one of the) \f(CW\(C`struct stat\(C'\fR types
		1382	suitable for your system. If the \f(CW\(C`st_nlink\(C'\fR member is \f(CW0\fR, then there
		1383	was some error while \f(CW\(C`stat\(C'\fRing the file.
		1384	.IP "ev_statdata prev [read\-only]" 4
		1385	.IX Item "ev_statdata prev [read-only]"
		1386	The previous attributes of the file. The callback gets invoked whenever
		1387	\&\f(CW\(C`prev\(C'\fR != \f(CW\(C`attr\(C'\fR.
		1388	.IP "ev_tstamp interval [read\-only]" 4
		1389	.IX Item "ev_tstamp interval [read-only]"
		1390	The specified interval.
		1391	.IP "const char *path [read\-only]" 4
		1392	.IX Item "const char *path [read-only]"
		1393	The filesystem path that is being watched.
		1394	.PP
		1395	Example: Watch \f(CW\(C`/etc/passwd\(C'\fR for attribute changes.
		1396	.PP
		1397	.Vb 15
		1398	\& static void
		1399	\& passwd_cb (struct ev_loop loop, ev_stat w, int revents)
		1400	\& {
		1401	\& /* /etc/passwd changed in some way */
		1402	\& if (w->attr.st_nlink)
		1403	\& {
		1404	\& printf ("passwd current size %ld\en", (long)w->attr.st_size);
		1405	\& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime);
		1406	\& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime);
		1407	\& }
		1408	\& else
		1409	\& /* you shalt not abuse printf for puts */
		1410	\& puts ("wow, /etc/passwd is not there, expect problems. "
		1411	\& "if this is windows, they already arrived\en");
		1412	\& }
		1413	.Ve
		1414	.PP
		1415	.Vb 2
		1416	\& ...
		1417	\& ev_stat passwd;
		1418	.Ve
		1419	.PP
		1420	.Vb 2
		1421	\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
		1422	\& ev_stat_start (loop, &passwd);
		1423	.Ve
1188	.ie n .Sh """ev_idle"" \- when you've got nothing better to do"	1424	.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
1189	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do"	1425	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
1190	.IX Subsection "ev_idle - when you've got nothing better to do"	1426	.IX Subsection "ev_idle - when you've got nothing better to do..."
1191	Idle watchers trigger events when there are no other events are pending	1427	Idle watchers trigger events when there are no other events are pending
1192	(prepare, check and other idle watchers do not count). That is, as long	1428	(prepare, check and other idle watchers do not count). That is, as long
1193	as your process is busy handling sockets or timeouts (or even signals,	1429	as your process is busy handling sockets or timeouts (or even signals,
1194	imagine) it will not be triggered. But when your process is idle all idle	1430	imagine) it will not be triggered. But when your process is idle all idle
1195	watchers are being called again and again, once per event loop iteration \-	1431	watchers are being called again and again, once per event loop iteration \-
…		…
1225	.Vb 3	1461	.Vb 3
1226	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1462	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1227	\& ev_idle_init (idle_watcher, idle_cb);	1463	\& ev_idle_init (idle_watcher, idle_cb);
1228	\& ev_idle_start (loop, idle_cb);	1464	\& ev_idle_start (loop, idle_cb);
1229	.Ve	1465	.Ve
1230	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop"	1466	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!"
1231	.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop"	1467	.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!"
1232	.IX Subsection "ev_prepare and ev_check - customise your event loop"	1468	.IX Subsection "ev_prepare and ev_check - customise your event loop!"
1233	Prepare and check watchers are usually (but not always) used in tandem:	1469	Prepare and check watchers are usually (but not always) used in tandem:
1234	prepare watchers get invoked before the process blocks and check watchers	1470	prepare watchers get invoked before the process blocks and check watchers
1235	afterwards.	1471	afterwards.
1236	.PP	1472	.PP
		1473	You \fImust not\fR call \f(CW\(C`ev_loop\(C'\fR or similar functions that enter
		1474	the current event loop from either \f(CW\(C`ev_prepare\(C'\fR or \f(CW\(C`ev_check\(C'\fR
		1475	watchers. Other loops than the current one are fine, however. The
		1476	rationale behind this is that you do not need to check for recursion in
		1477	those watchers, i.e. the sequence will always be \f(CW\(C`ev_prepare\(C'\fR, blocking,
		1478	\&\f(CW\(C`ev_check\(C'\fR so if you have one watcher of each kind they will always be
		1479	called in pairs bracketing the blocking call.
		1480	.PP
1237	Their main purpose is to integrate other event mechanisms into libev and	1481	Their main purpose is to integrate other event mechanisms into libev and
1238	their use is somewhat advanced. This could be used, for example, to track	1482	their use is somewhat advanced. This could be used, for example, to track
1239	variable changes, implement your own watchers, integrate net-snmp or a	1483	variable changes, implement your own watchers, integrate net-snmp or a
1240	coroutine library and lots more.	1484	coroutine library and lots more. They are also occasionally useful if
		1485	you cache some data and want to flush it before blocking (for example,
		1486	in X programs you might want to do an \f(CW\(C`XFlush ()\(C'\fR in an \f(CW\(C`ev_prepare\(C'\fR
		1487	watcher).
1241	.PP	1488	.PP
1242	This is done by examining in each prepare call which file descriptors need	1489	This is done by examining in each prepare call which file descriptors need
1243	to be watched by the other library, registering \f(CW\(C`ev_io\(C'\fR watchers for	1490	to be watched by the other library, registering \f(CW\(C`ev_io\(C'\fR watchers for
1244	them and starting an \f(CW\(C`ev_timer\(C'\fR watcher for any timeouts (many libraries	1491	them and starting an \f(CW\(C`ev_timer\(C'\fR watcher for any timeouts (many libraries
1245	provide just this functionality). Then, in the check watcher you check for	1492	provide just this functionality). Then, in the check watcher you check for
…		…
1264	.PD	1511	.PD
1265	Initialises and configures the prepare or check watcher \- they have no	1512	Initialises and configures the prepare or check watcher \- they have no
1266	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR	1513	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR
1267	macros, but using them is utterly, utterly and completely pointless.	1514	macros, but using them is utterly, utterly and completely pointless.
1268	.PP	1515	.PP
1269	Example: TODO.	1516	Example: To include a library such as adns, you would add \s-1IO\s0 watchers
		1517	and a timeout watcher in a prepare handler, as required by libadns, and
		1518	in a check watcher, destroy them and call into libadns. What follows is
		1519	pseudo-code only of course:
		1520	.PP
		1521	.Vb 2
		1522	\& static ev_io iow [nfd];
		1523	\& static ev_timer tw;
		1524	.Ve
		1525	.PP
		1526	.Vb 9
		1527	\& static void
		1528	\& io_cb (ev_loop loop, ev_io w, int revents)
		1529	\& {
		1530	\& // set the relevant poll flags
		1531	\& // could also call adns_processreadable etc. here
		1532	\& struct pollfd fd = (struct pollfd )w->data;
		1533	\& if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1534	\& if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1535	\& }
		1536	.Ve
		1537	.PP
		1538	.Vb 7
		1539	\& // create io watchers for each fd and a timer before blocking
		1540	\& static void
		1541	\& adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
		1542	\& {
		1543	\& int timeout = 3600000;truct pollfd fds [nfd];
		1544	\& // actual code will need to loop here and realloc etc.
		1545	\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
		1546	.Ve
		1547	.PP
		1548	.Vb 3
		1549	\& /* the callback is illegal, but won't be called as we stop during check */
		1550	\& ev_timer_init (&tw, 0, timeout * 1e-3);
		1551	\& ev_timer_start (loop, &tw);
		1552	.Ve
		1553	.PP
		1554	.Vb 6
		1555	\& // create on ev_io per pollfd
		1556	\& for (int i = 0; i < nfd; ++i)
		1557	\& {
		1558	\& ev_io_init (iow + i, io_cb, fds [i].fd,
		1559	\& ((fds [i].events & POLLIN ? EV_READ : 0)
		1560	\& \| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
		1561	.Ve
		1562	.PP
		1563	.Vb 5
		1564	\& fds [i].revents = 0;
		1565	\& iow [i].data = fds + i;
		1566	\& ev_io_start (loop, iow + i);
		1567	\& }
		1568	\& }
		1569	.Ve
		1570	.PP
		1571	.Vb 5
		1572	\& // stop all watchers after blocking
		1573	\& static void
		1574	\& adns_check_cb (ev_loop loop, ev_check w, int revents)
		1575	\& {
		1576	\& ev_timer_stop (loop, &tw);
		1577	.Ve
		1578	.PP
		1579	.Vb 2
		1580	\& for (int i = 0; i < nfd; ++i)
		1581	\& ev_io_stop (loop, iow + i);
		1582	.Ve
		1583	.PP
		1584	.Vb 2
		1585	\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1586	\& }
		1587	.Ve
1270	.ie n .Sh """ev_embed"" \- when one backend isn't enough"	1588	.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1271	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough"	1589	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1272	.IX Subsection "ev_embed - when one backend isn't enough"	1590	.IX Subsection "ev_embed - when one backend isn't enough..."
1273	This is a rather advanced watcher type that lets you embed one event loop	1591	This is a rather advanced watcher type that lets you embed one event loop
1274	into another (currently only \f(CW\(C`ev_io\(C'\fR events are supported in the embedded	1592	into another (currently only \f(CW\(C`ev_io\(C'\fR events are supported in the embedded
1275	loop, other types of watchers might be handled in a delayed or incorrect	1593	loop, other types of watchers might be handled in a delayed or incorrect
1276	fashion and must not be used).	1594	fashion and must not be used).
1277	.PP	1595	.PP
…		…
1357	.IP "ev_embed_sweep (loop, ev_embed *)" 4	1675	.IP "ev_embed_sweep (loop, ev_embed *)" 4
1358	.IX Item "ev_embed_sweep (loop, ev_embed *)"	1676	.IX Item "ev_embed_sweep (loop, ev_embed *)"
1359	Make a single, non-blocking sweep over the embedded loop. This works	1677	Make a single, non-blocking sweep over the embedded loop. This works
1360	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most	1678	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most
1361	apropriate way for embedded loops.	1679	apropriate way for embedded loops.
		1680	.IP "struct ev_loop *loop [read\-only]" 4
		1681	.IX Item "struct ev_loop *loop [read-only]"
		1682	The embedded event loop.
		1683	.ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork"
		1684	.el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
		1685	.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
		1686	Fork watchers are called when a \f(CW\(C`fork ()\(C'\fR was detected (usually because
		1687	whoever is a good citizen cared to tell libev about it by calling
		1688	\&\f(CW\(C`ev_default_fork\(C'\fR or \f(CW\(C`ev_loop_fork\(C'\fR). The invocation is done before the
		1689	event loop blocks next and before \f(CW\(C`ev_check\(C'\fR watchers are being called,
		1690	and only in the child after the fork. If whoever good citizen calling
		1691	\&\f(CW\(C`ev_default_fork\(C'\fR cheats and calls it in the wrong process, the fork
		1692	handlers will be invoked, too, of course.
		1693	.IP "ev_fork_init (ev_signal *, callback)" 4
		1694	.IX Item "ev_fork_init (ev_signal *, callback)"
		1695	Initialises and configures the fork watcher \- it has no parameters of any
		1696	kind. There is a \f(CW\(C`ev_fork_set\(C'\fR macro, but using it is utterly pointless,
		1697	believe me.
1362	.SH "OTHER FUNCTIONS"	1698	.SH "OTHER FUNCTIONS"
1363	.IX Header "OTHER FUNCTIONS"	1699	.IX Header "OTHER FUNCTIONS"
1364	There are some other functions of possible interest. Described. Here. Now.	1700	There are some other functions of possible interest. Described. Here. Now.
1365	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4	1701	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
1366	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"	1702	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
…		…
1428	.IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4	1764	.IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4
1429	.IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library."	1765	.IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library."
1430	.PD	1766	.PD
1431	.SH "\*(C+ SUPPORT"	1767	.SH "\*(C+ SUPPORT"
1432	.IX Header " SUPPORT"	1768	.IX Header " SUPPORT"
1433	\&\s-1TBD\s0.	1769	Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow
		1770	you to use some convinience methods to start/stop watchers and also change
		1771	the callback model to a model using method callbacks on objects.
		1772	.PP
		1773	To use it,
		1774	.PP
		1775	.Vb 1
		1776	\& #include <ev++.h>
		1777	.Ve
		1778	.PP
		1779	(it is not installed by default). This automatically includes \fIev.h\fR
		1780	and puts all of its definitions (many of them macros) into the global
		1781	namespace. All \(C+ specific things are put into the \f(CW\(C`ev\*(C'\fR namespace.
		1782	.PP
		1783	It should support all the same embedding options as \fIev.h\fR, most notably
		1784	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR.
		1785	.PP
		1786	Here is a list of things available in the \f(CW\(C`ev\(C'\fR namespace:
		1787	.ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4
		1788	.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4
		1789	.IX Item "ev::READ, ev::WRITE etc."
		1790	These are just enum values with the same values as the \f(CW\(C`EV_READ\(C'\fR etc.
		1791	macros from \fIev.h\fR.
		1792	.ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4
		1793	.el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4
		1794	.IX Item "ev::tstamp, ev::now"
		1795	Aliases to the same types/functions as with the \f(CW\(C`ev_\(C'\fR prefix.
		1796	.ie n .IP """ev::io""\fR, \f(CW""ev::timer""\fR, \f(CW""ev::periodic""\fR, \f(CW""ev::idle""\fR, \f(CW""ev::sig"" etc." 4
		1797	.el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4
		1798	.IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc."
		1799	For each \f(CW\(C`ev_TYPE\(C'\fR watcher in \fIev.h\fR there is a corresponding class of
		1800	the same name in the \f(CW\(C`ev\(C'\fR namespace, with the exception of \f(CW\(C`ev_signal\(C'\fR
		1801	which is called \f(CW\(C`ev::sig\(C'\fR to avoid clashes with the \f(CW\(C`signal\(C'\fR macro
		1802	defines by many implementations.
		1803	.Sp
		1804	All of those classes have these methods:
		1805	.RS 4
		1806	.IP "ev::TYPE::TYPE (object , object::method )" 4
		1807	.IX Item "ev::TYPE::TYPE (object , object::method )"
		1808	.PD 0
		1809	.IP "ev::TYPE::TYPE (object , object::method , struct ev_loop *)" 4
		1810	.IX Item "ev::TYPE::TYPE (object , object::method , struct ev_loop *)"
		1811	.IP "ev::TYPE::~TYPE" 4
		1812	.IX Item "ev::TYPE::~TYPE"
		1813	.PD
		1814	The constructor takes a pointer to an object and a method pointer to
		1815	the event handler callback to call in this class. The constructor calls
		1816	\&\f(CW\(C`ev_init\(C'\fR for you, which means you have to call the \f(CW\(C`set\(C'\fR method
		1817	before starting it. If you do not specify a loop then the constructor
		1818	automatically associates the default loop with this watcher.
		1819	.Sp
		1820	The destructor automatically stops the watcher if it is active.
		1821	.IP "w\->set (struct ev_loop *)" 4
		1822	.IX Item "w->set (struct ev_loop *)"
		1823	Associates a different \f(CW\(C`struct ev_loop\(C'\fR with this watcher. You can only
		1824	do this when the watcher is inactive (and not pending either).
		1825	.IP "w\->set ([args])" 4
		1826	.IX Item "w->set ([args])"
		1827	Basically the same as \f(CW\(C`ev_TYPE_set\(C'\fR, with the same args. Must be
		1828	called at least once. Unlike the C counterpart, an active watcher gets
		1829	automatically stopped and restarted.
		1830	.IP "w\->start ()" 4
		1831	.IX Item "w->start ()"
		1832	Starts the watcher. Note that there is no \f(CW\(C`loop\(C'\fR argument as the
		1833	constructor already takes the loop.
		1834	.IP "w\->stop ()" 4
		1835	.IX Item "w->stop ()"
		1836	Stops the watcher if it is active. Again, no \f(CW\(C`loop\(C'\fR argument.
		1837	.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4
		1838	.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4
		1839	.IX Item "w->again () ev::timer, ev::periodic only"
		1840	For \f(CW\(C`ev::timer\(C'\fR and \f(CW\(C`ev::periodic\(C'\fR, this invokes the corresponding
		1841	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.
		1842	.ie n .IP "w\->sweep () ""ev::embed"" only" 4
		1843	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
		1844	.IX Item "w->sweep () ev::embed only"
		1845	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.
		1846	.ie n .IP "w\->update () ""ev::stat"" only" 4
		1847	.el .IP "w\->update () \f(CWev::stat\fR only" 4
		1848	.IX Item "w->update () ev::stat only"
		1849	Invokes \f(CW\(C`ev_stat_stat\(C'\fR.
		1850	.RE
		1851	.RS 4
		1852	.RE
		1853	.PP
		1854	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
		1855	the constructor.
		1856	.PP
		1857	.Vb 4
		1858	\& class myclass
		1859	\& {
		1860	\& ev_io io; void io_cb (ev::io &w, int revents);
		1861	\& ev_idle idle void idle_cb (ev::idle &w, int revents);
		1862	.Ve
		1863	.PP
		1864	.Vb 2
		1865	\& myclass ();
		1866	\& }
		1867	.Ve
		1868	.PP
		1869	.Vb 6
		1870	\& myclass::myclass (int fd)
		1871	\& : io (this, &myclass::io_cb),
		1872	\& idle (this, &myclass::idle_cb)
		1873	\& {
		1874	\& io.start (fd, ev::READ);
		1875	\& }
		1876	.Ve
		1877	.SH "MACRO MAGIC"
		1878	.IX Header "MACRO MAGIC"
		1879	Libev can be compiled with a variety of options, the most fundemantal is
		1880	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR. This option determines wether (most) functions and
		1881	callbacks have an initial \f(CW\(C`struct ev_loop \*(C'\fR argument.
		1882	.PP
		1883	To make it easier to write programs that cope with either variant, the
		1884	following macros are defined:
		1885	.ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4
		1886	.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
		1887	.IX Item "EV_A, EV_A_"
		1888	This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
		1889	loop argument\(R"). The \f(CW\(C`EV_A\*(C'\fR form is used when this is the sole argument,
		1890	\&\f(CW\(C`EV_A_\(C'\fR is used when other arguments are following. Example:
		1891	.Sp
		1892	.Vb 3
		1893	\& ev_unref (EV_A);
		1894	\& ev_timer_add (EV_A_ watcher);
		1895	\& ev_loop (EV_A_ 0);
		1896	.Ve
		1897	.Sp
		1898	It assumes the variable \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR is in scope,
		1899	which is often provided by the following macro.
		1900	.ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4
		1901	.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
		1902	.IX Item "EV_P, EV_P_"
		1903	This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
		1904	loop parameter\(R"). The \f(CW\(C`EV_P\*(C'\fR form is used when this is the sole parameter,
		1905	\&\f(CW\(C`EV_P_\(C'\fR is used when other parameters are following. Example:
		1906	.Sp
		1907	.Vb 2
		1908	\& // this is how ev_unref is being declared
		1909	\& static void ev_unref (EV_P);
		1910	.Ve
		1911	.Sp
		1912	.Vb 2
		1913	\& // this is how you can declare your typical callback
		1914	\& static void cb (EV_P_ ev_timer *w, int revents)
		1915	.Ve
		1916	.Sp
		1917	It declares a parameter \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR, quite
		1918	suitable for use with \f(CW\(C`EV_A\(C'\fR.
		1919	.ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4
		1920	.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
		1921	.IX Item "EV_DEFAULT, EV_DEFAULT_"
		1922	Similar to the other two macros, this gives you the value of the default
		1923	loop, if multiple loops are supported (\(L"ev loop default\(R").
		1924	.PP
		1925	Example: Declare and initialise a check watcher, working regardless of
		1926	wether multiple loops are supported or not.
		1927	.PP
		1928	.Vb 5
		1929	\& static void
		1930	\& check_cb (EV_P_ ev_timer *w, int revents)
		1931	\& {
		1932	\& ev_check_stop (EV_A_ w);
		1933	\& }
		1934	.Ve
		1935	.PP
		1936	.Vb 4
		1937	\& ev_check check;
		1938	\& ev_check_init (&check, check_cb);
		1939	\& ev_check_start (EV_DEFAULT_ &check);
		1940	\& ev_loop (EV_DEFAULT_ 0);
		1941	.Ve
		1942	.SH "EMBEDDING"
		1943	.IX Header "EMBEDDING"
		1944	Libev can (and often is) directly embedded into host
		1945	applications. Examples of applications that embed it include the Deliantra
		1946	Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe)
		1947	and rxvt\-unicode.
		1948	.PP
		1949	The goal is to enable you to just copy the neecssary files into your
		1950	source directory without having to change even a single line in them, so
		1951	you can easily upgrade by simply copying (or having a checked-out copy of
		1952	libev somewhere in your source tree).
		1953	.Sh "\s-1FILESETS\s0"
		1954	.IX Subsection "FILESETS"
		1955	Depending on what features you need you need to include one or more sets of files
		1956	in your app.
		1957	.PP
		1958	\fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR
		1959	.IX Subsection "CORE EVENT LOOP"
		1960	.PP
		1961	To include only the libev core (all the \f(CW\(C`ev_\*(C'\fR functions), with manual
		1962	configuration (no autoconf):
		1963	.PP
		1964	.Vb 2
		1965	\& #define EV_STANDALONE 1
		1966	\& #include "ev.c"
		1967	.Ve
		1968	.PP
		1969	This will automatically include \fIev.h\fR, too, and should be done in a
		1970	single C source file only to provide the function implementations. To use
		1971	it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best
		1972	done by writing a wrapper around \fIev.h\fR that you can include instead and
		1973	where you can put other configuration options):
		1974	.PP
		1975	.Vb 2
		1976	\& #define EV_STANDALONE 1
		1977	\& #include "ev.h"
		1978	.Ve
		1979	.PP
		1980	Both header files and implementation files can be compiled with a \*(C+
		1981	compiler (at least, thats a stated goal, and breakage will be treated
		1982	as a bug).
		1983	.PP
		1984	You need the following files in your source tree, or in a directory
		1985	in your include path (e.g. in libev/ when using \-Ilibev):
		1986	.PP
		1987	.Vb 4
		1988	\& ev.h
		1989	\& ev.c
		1990	\& ev_vars.h
		1991	\& ev_wrap.h
		1992	.Ve
		1993	.PP
		1994	.Vb 1
		1995	\& ev_win32.c required on win32 platforms only
		1996	.Ve
		1997	.PP
		1998	.Vb 5
		1999	\& ev_select.c only when select backend is enabled (which is by default)
		2000	\& ev_poll.c only when poll backend is enabled (disabled by default)
		2001	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
		2002	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
		2003	\& ev_port.c only when the solaris port backend is enabled (disabled by default)
		2004	.Ve
		2005	.PP
		2006	\&\fIev.c\fR includes the backend files directly when enabled, so you only need
		2007	to compile this single file.
		2008	.PP
		2009	\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR
		2010	.IX Subsection "LIBEVENT COMPATIBILITY API"
		2011	.PP
		2012	To include the libevent compatibility \s-1API\s0, also include:
		2013	.PP
		2014	.Vb 1
		2015	\& #include "event.c"
		2016	.Ve
		2017	.PP
		2018	in the file including \fIev.c\fR, and:
		2019	.PP
		2020	.Vb 1
		2021	\& #include "event.h"
		2022	.Ve
		2023	.PP
		2024	in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR.
		2025	.PP
		2026	You need the following additional files for this:
		2027	.PP
		2028	.Vb 2
		2029	\& event.h
		2030	\& event.c
		2031	.Ve
		2032	.PP
		2033	\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR
		2034	.IX Subsection "AUTOCONF SUPPORT"
		2035	.PP
		2036	Instead of using \f(CW\(C`EV_STANDALONE=1\(C'\fR and providing your config in
		2037	whatever way you want, you can also \f(CW\(C`m4_include([libev.m4])\(C'\fR in your
		2038	\&\fIconfigure.ac\fR and leave \f(CW\(C`EV_STANDALONE\(C'\fR undefined. \fIev.c\fR will then
		2039	include \fIconfig.h\fR and configure itself accordingly.
		2040	.PP
		2041	For this of course you need the m4 file:
		2042	.PP
		2043	.Vb 1
		2044	\& libev.m4
		2045	.Ve
		2046	.Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0"
		2047	.IX Subsection "PREPROCESSOR SYMBOLS/MACROS"
		2048	Libev can be configured via a variety of preprocessor symbols you have to define
		2049	before including any of its files. The default is not to build for multiplicity
		2050	and only include the select backend.
		2051	.IP "\s-1EV_STANDALONE\s0" 4
		2052	.IX Item "EV_STANDALONE"
		2053	Must always be \f(CW1\fR if you do not use autoconf configuration, which
		2054	keeps libev from including \fIconfig.h\fR, and it also defines dummy
		2055	implementations for some libevent functions (such as logging, which is not
		2056	supported). It will also not define any of the structs usually found in
		2057	\&\fIevent.h\fR that are not directly supported by the libev core alone.
		2058	.IP "\s-1EV_USE_MONOTONIC\s0" 4
		2059	.IX Item "EV_USE_MONOTONIC"
		2060	If defined to be \f(CW1\fR, libev will try to detect the availability of the
		2061	monotonic clock option at both compiletime and runtime. Otherwise no use
		2062	of the monotonic clock option will be attempted. If you enable this, you
		2063	usually have to link against librt or something similar. Enabling it when
		2064	the functionality isn't available is safe, though, althoguh you have
		2065	to make sure you link against any libraries where the \f(CW\(C`clock_gettime\(C'\fR
		2066	function is hiding in (often \fI\-lrt\fR).
		2067	.IP "\s-1EV_USE_REALTIME\s0" 4
		2068	.IX Item "EV_USE_REALTIME"
		2069	If defined to be \f(CW1\fR, libev will try to detect the availability of the
		2070	realtime clock option at compiletime (and assume its availability at
		2071	runtime if successful). Otherwise no use of the realtime clock option will
		2072	be attempted. This effectively replaces \f(CW\(C`gettimeofday\(C'\fR by \f(CW\*(C`clock_get
		2073	(CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries
		2074	in the description of \f(CW\(C`EV_USE_MONOTONIC\(C'\fR, though.
		2075	.IP "\s-1EV_USE_SELECT\s0" 4
		2076	.IX Item "EV_USE_SELECT"
		2077	If undefined or defined to be \f(CW1\fR, libev will compile in support for the
		2078	\&\f(CW\(C`select\(C'\fR(2) backend. No attempt at autodetection will be done: if no
		2079	other method takes over, select will be it. Otherwise the select backend
		2080	will not be compiled in.
		2081	.IP "\s-1EV_SELECT_USE_FD_SET\s0" 4
		2082	.IX Item "EV_SELECT_USE_FD_SET"
		2083	If defined to \f(CW1\fR, then the select backend will use the system \f(CW\(C`fd_set\(C'\fR
		2084	structure. This is useful if libev doesn't compile due to a missing
		2085	\&\f(CW\(C`NFDBITS\(C'\fR or \f(CW\(C`fd_mask\(C'\fR definition or it misguesses the bitset layout on
		2086	exotic systems. This usually limits the range of file descriptors to some
		2087	low limit such as 1024 or might have other limitations (winsocket only
		2088	allows 64 sockets). The \f(CW\(C`FD_SETSIZE\(C'\fR macro, set before compilation, might
		2089	influence the size of the \f(CW\(C`fd_set\(C'\fR used.
		2090	.IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4
		2091	.IX Item "EV_SELECT_IS_WINSOCKET"
		2092	When defined to \f(CW1\fR, the select backend will assume that
		2093	select/socket/connect etc. don't understand file descriptors but
		2094	wants osf handles on win32 (this is the case when the select to
		2095	be used is the winsock select). This means that it will call
		2096	\&\f(CW\(C`_get_osfhandle\(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise,
		2097	it is assumed that all these functions actually work on fds, even
		2098	on win32. Should not be defined on non\-win32 platforms.
		2099	.IP "\s-1EV_USE_POLL\s0" 4
		2100	.IX Item "EV_USE_POLL"
		2101	If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\(C`poll\(C'\fR(2)
		2102	backend. Otherwise it will be enabled on non\-win32 platforms. It
		2103	takes precedence over select.
		2104	.IP "\s-1EV_USE_EPOLL\s0" 4
		2105	.IX Item "EV_USE_EPOLL"
		2106	If defined to be \f(CW1\fR, libev will compile in support for the Linux
		2107	\&\f(CW\(C`epoll\(C'\fR(7) backend. Its availability will be detected at runtime,
		2108	otherwise another method will be used as fallback. This is the
		2109	preferred backend for GNU/Linux systems.
		2110	.IP "\s-1EV_USE_KQUEUE\s0" 4
		2111	.IX Item "EV_USE_KQUEUE"
		2112	If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style
		2113	\&\f(CW\(C`kqueue\(C'\fR(2) backend. Its actual availability will be detected at runtime,
		2114	otherwise another method will be used as fallback. This is the preferred
		2115	backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only
		2116	supports some types of fds correctly (the only platform we found that
		2117	supports ptys for example was NetBSD), so kqueue might be compiled in, but
		2118	not be used unless explicitly requested. The best way to use it is to find
		2119	out whether kqueue supports your type of fd properly and use an embedded
		2120	kqueue loop.
		2121	.IP "\s-1EV_USE_PORT\s0" 4
		2122	.IX Item "EV_USE_PORT"
		2123	If defined to be \f(CW1\fR, libev will compile in support for the Solaris
		2124	10 port style backend. Its availability will be detected at runtime,
		2125	otherwise another method will be used as fallback. This is the preferred
		2126	backend for Solaris 10 systems.
		2127	.IP "\s-1EV_USE_DEVPOLL\s0" 4
		2128	.IX Item "EV_USE_DEVPOLL"
		2129	reserved for future expansion, works like the \s-1USE\s0 symbols above.
		2130	.IP "\s-1EV_H\s0" 4
		2131	.IX Item "EV_H"
		2132	The name of the \fIev.h\fR header file used to include it. The default if
		2133	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
		2134	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
		2135	.IP "\s-1EV_CONFIG_H\s0" 4
		2136	.IX Item "EV_CONFIG_H"
		2137	If \f(CW\(C`EV_STANDALONE\(C'\fR isn't \f(CW1\fR, this variable can be used to override
		2138	\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
		2139	\&\f(CW\(C`EV_H\(C'\fR, above.
		2140	.IP "\s-1EV_EVENT_H\s0" 4
		2141	.IX Item "EV_EVENT_H"
		2142	Similarly to \f(CW\(C`EV_H\(C'\fR, this macro can be used to override \fIevent.c\fR's idea
		2143	of how the \fIevent.h\fR header can be found.
		2144	.IP "\s-1EV_PROTOTYPES\s0" 4
		2145	.IX Item "EV_PROTOTYPES"
		2146	If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
		2147	prototypes, but still define all the structs and other symbols. This is
		2148	occasionally useful if you want to provide your own wrapper functions
		2149	around libev functions.
		2150	.IP "\s-1EV_MULTIPLICITY\s0" 4
		2151	.IX Item "EV_MULTIPLICITY"
		2152	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
		2153	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create
		2154	additional independent event loops. Otherwise there will be no support
		2155	for multiple event loops and there is no first event loop pointer
		2156	argument. Instead, all functions act on the single default loop.
		2157	.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
		2158	.IX Item "EV_PERIODIC_ENABLE"
		2159	If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
		2160	defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
		2161	code.
		2162	.IP "\s-1EV_EMBED_ENABLE\s0" 4
		2163	.IX Item "EV_EMBED_ENABLE"
		2164	If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
		2165	defined to be \f(CW0\fR, then they are not.
		2166	.IP "\s-1EV_STAT_ENABLE\s0" 4
		2167	.IX Item "EV_STAT_ENABLE"
		2168	If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
		2169	defined to be \f(CW0\fR, then they are not.
		2170	.IP "\s-1EV_FORK_ENABLE\s0" 4
		2171	.IX Item "EV_FORK_ENABLE"
		2172	If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If
		2173	defined to be \f(CW0\fR, then they are not.
		2174	.IP "\s-1EV_MINIMAL\s0" 4
		2175	.IX Item "EV_MINIMAL"
		2176	If you need to shave off some kilobytes of code at the expense of some
		2177	speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
		2178	some inlining decisions, saves roughly 30% codesize of amd64.
		2179	.IP "\s-1EV_PID_HASHSIZE\s0" 4
		2180	.IX Item "EV_PID_HASHSIZE"
		2181	\&\f(CW\(C`ev_child\(C'\fR watchers use a small hash table to distribute workload by
		2182	pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\(C`EV_MINIMAL\(C'\fR), usually more
		2183	than enough. If you need to manage thousands of children you might want to
		2184	increase this value.
		2185	.IP "\s-1EV_COMMON\s0" 4
		2186	.IX Item "EV_COMMON"
		2187	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining
		2188	this macro to a something else you can include more and other types of
		2189	members. You have to define it each time you include one of the files,
		2190	though, and it must be identical each time.
		2191	.Sp
		2192	For example, the perl \s-1EV\s0 module uses something like this:
		2193	.Sp
		2194	.Vb 3
		2195	\& #define EV_COMMON \e
		2196	\& SV self; / contains this struct */ \e
		2197	\& SV cb_sv, fh /* note no trailing ";" */
		2198	.Ve
		2199	.IP "\s-1EV_CB_DECLARE\s0 (type)" 4
		2200	.IX Item "EV_CB_DECLARE (type)"
		2201	.PD 0
		2202	.IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4
		2203	.IX Item "EV_CB_INVOKE (watcher, revents)"
		2204	.IP "ev_set_cb (ev, cb)" 4
		2205	.IX Item "ev_set_cb (ev, cb)"
		2206	.PD
		2207	Can be used to change the callback member declaration in each watcher,
		2208	and the way callbacks are invoked and set. Must expand to a struct member
		2209	definition and a statement, respectively. See the \fIev.v\fR header file for
		2210	their default definitions. One possible use for overriding these is to
		2211	avoid the \f(CW\(C`struct ev_loop \*(C'\fR as first argument in all cases, or to use
		2212	method calls instead of plain function calls in \*(C+.
		2213	.Sh "\s-1EXAMPLES\s0"
		2214	.IX Subsection "EXAMPLES"
		2215	For a real-world example of a program the includes libev
		2216	verbatim, you can have a look at the \s-1EV\s0 perl module
		2217	(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
		2218	the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public
		2219	interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
		2220	will be compiled. It is pretty complex because it provides its own header
		2221	file.
		2222	.Sp
		2223	The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
		2224	that everybody includes and which overrides some autoconf choices:
		2225	.Sp
		2226	.Vb 4
		2227	\& #define EV_USE_POLL 0
		2228	\& #define EV_MULTIPLICITY 0
		2229	\& #define EV_PERIODICS 0
		2230	\& #define EV_CONFIG_H <config.h>
		2231	.Ve
		2232	.Sp
		2233	.Vb 1
		2234	\& #include "ev++.h"
		2235	.Ve
		2236	.Sp
		2237	And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled:
		2238	.Sp
		2239	.Vb 2
		2240	\& #include "ev_cpp.h"
		2241	\& #include "ev.c"
		2242	.Ve
		2243	.SH "COMPLEXITIES"
		2244	.IX Header "COMPLEXITIES"
		2245	In this section the complexities of (many of) the algorithms used inside
		2246	libev will be explained. For complexity discussions about backends see the
		2247	documentation for \f(CW\(C`ev_default_init\(C'\fR.
		2248	.RS 4
		2249	.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
		2250	.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
		2251	.PD 0
		2252	.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4
		2253	.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
		2254	.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
		2255	.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
		2256	.IP "Stopping check/prepare/idle watchers: O(1)" 4
		2257	.IX Item "Stopping check/prepare/idle watchers: O(1)"
		2258	.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4
		2259	.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))"
		2260	.IP "Finding the next timer per loop iteration: O(1)" 4
		2261	.IX Item "Finding the next timer per loop iteration: O(1)"
		2262	.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
		2263	.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
		2264	.IP "Activating one watcher: O(1)" 4
		2265	.IX Item "Activating one watcher: O(1)"
		2266	.RE
		2267	.RS 4
		2268	.PD
1434	.SH "AUTHOR"	2269	.SH "AUTHOR"
1435	.IX Header "AUTHOR"	2270	.IX Header "AUTHOR"
1436	Marc Lehmann <libev@schmorp.de>.	2271	Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.3 (file contents): Revision 1.11 by root, Sat Nov 24 07:14:26 2007 UTC vs. Revision 1.27 by root, Tue Nov 27 20:15:01 2007 UTC

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Comparing libev/ev.3 (file contents):
Revision 1.11 by root, Sat Nov 24 07:14:26 2007 UTC vs.
Revision 1.27 by root, Tue Nov 27 20:15:01 2007 UTC