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

Comparing libev/ev.3 (file contents):
Revision 1.16 by root, Sat Nov 24 10:19:14 2007 UTC vs.
Revision 1.24 by root, Tue Nov 27 10:59:10 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 1
…		…
684	The signal specified in the \f(CW\(C`ev_signal\(C'\fR watcher has been received by a thread.	684	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	685	.ie n .IP """EV_CHILD""" 4
686	.el .IP "\f(CWEV_CHILD\fR" 4	686	.el .IP "\f(CWEV_CHILD\fR" 4
687	.IX Item "EV_CHILD"	687	.IX Item "EV_CHILD"
688	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.	688	The pid specified in the \f(CW\(C`ev_child\(C'\fR watcher has received a status change.
		689	.ie n .IP """EV_STAT""" 4
		690	.el .IP "\f(CWEV_STAT\fR" 4
		691	.IX Item "EV_STAT"
		692	The path specified in the \f(CW\(C`ev_stat\(C'\fR watcher changed its attributes somehow.
689	.ie n .IP """EV_IDLE""" 4	693	.ie n .IP """EV_IDLE""" 4
690	.el .IP "\f(CWEV_IDLE\fR" 4	694	.el .IP "\f(CWEV_IDLE\fR" 4
691	.IX Item "EV_IDLE"	695	.IX Item "EV_IDLE"
692	The \f(CW\(C`ev_idle\(C'\fR watcher has determined that you have nothing better to do.	696	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	697	.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	707	\&\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	708	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	709	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	710	(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).	711	\&\f(CW\(C`ev_loop\(C'\fR from blocking).
		712	.ie n .IP """EV_EMBED""" 4
		713	.el .IP "\f(CWEV_EMBED\fR" 4
		714	.IX Item "EV_EMBED"
		715	The embedded event loop specified in the \f(CW\(C`ev_embed\(C'\fR watcher needs attention.
		716	.ie n .IP """EV_FORK""" 4
		717	.el .IP "\f(CWEV_FORK\fR" 4
		718	.IX Item "EV_FORK"
		719	The event loop has been resumed in the child process after fork (see
		720	\&\f(CW\(C`ev_fork\(C'\fR).
708	.ie n .IP """EV_ERROR""" 4	721	.ie n .IP """EV_ERROR""" 4
709	.el .IP "\f(CWEV_ERROR\fR" 4	722	.el .IP "\f(CWEV_ERROR\fR" 4
710	.IX Item "EV_ERROR"	723	.IX Item "EV_ERROR"
711	An unspecified error has occured, the watcher has been stopped. This might	724	An unspecified error has occured, the watcher has been stopped. This might
712	happen because the watcher could not be properly started because libev	725	happen because the watcher could not be properly started because libev
…		…
717	Libev will usually signal a few \(L"dummy\(R" events together with an error,	730	Libev will usually signal a few \(L"dummy\(R" events together with an error,
718	for example it might indicate that a fd is readable or writable, and if	731	for example it might indicate that a fd is readable or writable, and if
719	your callbacks is well-written it can just attempt the operation and cope	732	your callbacks is well-written it can just attempt the operation and cope
720	with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded	733	with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded
721	programs, though, so beware.	734	programs, though, so beware.
722	.Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"	735	.Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"
723	.IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS"	736	.IX Subsection "GENERIC WATCHER FUNCTIONS"
724	In the following description, \f(CW\(C`TYPE\(C'\fR stands for the watcher type,	737	In the following description, \f(CW\(C`TYPE\(C'\fR stands for the watcher type,
725	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.	738	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.
726	.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4	739	.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
727	.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4	740	.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4
728	.IX Item "ev_init (ev_TYPE *watcher, callback)"	741	.IX Item "ev_init (ev_TYPE *watcher, callback)"
…		…
734	which rolls both calls into one.	747	which rolls both calls into one.
735	.Sp	748	.Sp
736	You can reinitialise a watcher at any time as long as it has been stopped	749	You can reinitialise a watcher at any time as long as it has been stopped
737	(or never started) and there are no pending events outstanding.	750	(or never started) and there are no pending events outstanding.
738	.Sp	751	.Sp
739	The callbakc is always of type \f(CW\(C`void ()(ev_loop loop, ev_TYPE watcher,	752	The callback is always of type \f(CW\(C`void ()(ev_loop loop, ev_TYPE watcher,
740	int revents)\*(C'\fR.	753	int revents)\*(C'\fR.
741	.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4	754	.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4
742	.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4	755	.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4
743	.IX Item "ev_TYPE_set (ev_TYPE *, [args])"	756	.IX Item "ev_TYPE_set (ev_TYPE *, [args])"
744	This macro initialises the type-specific parts of a watcher. You need to	757	This macro initialises the type-specific parts of a watcher. You need to
…		…
821	More interesting and less C\-conformant ways of catsing your callback type	834	More interesting and less C\-conformant ways of catsing your callback type
822	have been omitted....	835	have been omitted....
823	.SH "WATCHER TYPES"	836	.SH "WATCHER TYPES"
824	.IX Header "WATCHER TYPES"	837	.IX Header "WATCHER TYPES"
825	This section describes each watcher in detail, but will not repeat	838	This section describes each watcher in detail, but will not repeat
826	information given in the last section.	839	information given in the last section. Any initialisation/set macros,
		840	functions and members specific to the watcher type are explained.
		841	.PP
		842	Members are additionally marked with either \fI[read\-only]\fR, meaning that,
		843	while the watcher is active, you can look at the member and expect some
		844	sensible content, but you must not modify it (you can modify it while the
		845	watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
		846	means you can expect it to have some sensible content while the watcher
		847	is active, but you can also modify it. Modifying it may not do something
		848	sensible or take immediate effect (or do anything at all), but libev will
		849	not crash or malfunction in any way.
827	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable"	850	.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"	851	.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"	852	.IX Subsection "ev_io - is this file descriptor readable or writable?"
830	I/O watchers check whether a file descriptor is readable or writable	853	I/O watchers check whether a file descriptor is readable or writable
831	in each iteration of the event loop (This behaviour is called	854	in each iteration of the event loop, or, more precisely, when reading
832	level-triggering because you keep receiving events as long as the	855	would not block the process and writing would at least be able to write
833	condition persists. Remember you can stop the watcher if you don't want to	856	some data. This behaviour is called level-triggering because you keep
834	act on the event and neither want to receive future events).	857	receiving events as long as the condition persists. Remember you can stop
		858	the watcher if you don't want to act on the event and neither want to
		859	receive future events.
835	.PP	860	.PP
836	In general you can register as many read and/or write event watchers per	861	In general you can register as many read and/or write event watchers per
837	fd as you want (as long as you don't confuse yourself). Setting all file	862	fd as you want (as long as you don't confuse yourself). Setting all file
838	descriptors to non-blocking mode is also usually a good idea (but not	863	descriptors to non-blocking mode is also usually a good idea (but not
839	required if you know what you are doing).	864	required if you know what you are doing).
840	.PP	865	.PP
841	You have to be careful with dup'ed file descriptors, though. Some backends	866	You have to be careful with dup'ed file descriptors, though. Some backends
842	(the linux epoll backend is a notable example) cannot handle dup'ed file	867	(the linux epoll backend is a notable example) cannot handle dup'ed file
843	descriptors correctly if you register interest in two or more fds pointing	868	descriptors correctly if you register interest in two or more fds pointing
844	to the same underlying file/socket etc. description (that is, they share	869	to the same underlying file/socket/etc. description (that is, they share
845	the same underlying \(L"file open\(R").	870	the same underlying \(L"file open\(R").
846	.PP	871	.PP
847	If you must do this, then force the use of a known-to-be-good backend	872	If you must do this, then force the use of a known-to-be-good backend
848	(at the time of this writing, this includes only \f(CW\(C`EVBACKEND_SELECT\(C'\fR and	873	(at the time of this writing, this includes only \f(CW\(C`EVBACKEND_SELECT\(C'\fR and
849	\&\f(CW\(C`EVBACKEND_POLL\(C'\fR).	874	\&\f(CW\(C`EVBACKEND_POLL\(C'\fR).
		875	.PP
		876	Another thing you have to watch out for is that it is quite easy to
		877	receive \(L"spurious\(R" readyness notifications, that is your callback might
		878	be called with \f(CW\(C`EV_READ\(C'\fR but a subsequent \f(CW\(C`read\(C'\fR(2) will actually block
		879	because there is no data. Not only are some backends known to create a
		880	lot of those (for example solaris ports), it is very easy to get into
		881	this situation even with a relatively standard program structure. Thus
		882	it is best to always use non-blocking I/O: An extra \f(CW\(C`read\(C'\fR(2) returning
		883	\&\f(CW\(C`EAGAIN\(C'\fR is far preferable to a program hanging until some data arrives.
		884	.PP
		885	If you cannot run the fd in non-blocking mode (for example you should not
		886	play around with an Xlib connection), then you have to seperately re-test
		887	wether a file descriptor is really ready with a known-to-be good interface
		888	such as poll (fortunately in our Xlib example, Xlib already does this on
		889	its own, so its quite safe to use).
850	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4	890	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
851	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"	891	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
852	.PD 0	892	.PD 0
853	.IP "ev_io_set (ev_io *, int fd, int events)" 4	893	.IP "ev_io_set (ev_io *, int fd, int events)" 4
854	.IX Item "ev_io_set (ev_io *, int fd, int events)"	894	.IX Item "ev_io_set (ev_io *, int fd, int events)"
855	.PD	895	.PD
856	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The fd is the file descriptor to rceeive	896	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The \f(CW\(C`fd\(C'\fR is the file descriptor to
857	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 \|	897	rceeive events for and events is either \f(CW\(C`EV_READ\(C'\fR, \f(CW\(C`EV_WRITE\(C'\fR or
858	EV_WRITE\*(C'\fR to receive the given events.	898	\&\f(CW\(C`EV_READ \| EV_WRITE\(C'\fR to receive the given events.
859	.Sp	899	.IP "int fd [read\-only]" 4
860	Please note that most of the more scalable backend mechanisms (for example	900	.IX Item "int fd [read-only]"
861	epoll and solaris ports) can result in spurious readyness notifications	901	The file descriptor being watched.
862	for file descriptors, so you practically need to use non-blocking I/O (and	902	.IP "int events [read\-only]" 4
863	treat callback invocation as hint only), or retest separately with a safe	903	.IX Item "int events [read-only]"
864	interface before doing I/O (XLib can do this), or force the use of either	904	The events being watched.
865	\&\f(CW\(C`EVBACKEND_SELECT\(C'\fR or \f(CW\(C`EVBACKEND_POLL\(C'\fR, which don't suffer from this
866	problem. Also note that it is quite easy to have your callback invoked
867	when the readyness condition is no longer valid even when employing
868	typical ways of handling events, so its a good idea to use non-blocking
869	I/O unconditionally.
870	.PP	905	.PP
871	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well	906	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well
872	readable, but only once. Since it is likely line\-buffered, you could	907	readable, but only once. Since it is likely line\-buffered, you could
873	attempt to read a whole line in the callback:	908	attempt to read a whole line in the callback:
874	.PP	909	.PP
…		…
887	\& struct ev_io stdin_readable;	922	\& struct ev_io stdin_readable;
888	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	923	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
889	\& ev_io_start (loop, &stdin_readable);	924	\& ev_io_start (loop, &stdin_readable);
890	\& ev_loop (loop, 0);	925	\& ev_loop (loop, 0);
891	.Ve	926	.Ve
892	.ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts"	927	.ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts"
893	.el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts"	928	.el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts"
894	.IX Subsection "ev_timer - relative and optionally recurring timeouts"	929	.IX Subsection "ev_timer - relative and optionally repeating timeouts"
895	Timer watchers are simple relative timers that generate an event after a	930	Timer watchers are simple relative timers that generate an event after a
896	given time, and optionally repeating in regular intervals after that.	931	given time, and optionally repeating in regular intervals after that.
897	.PP	932	.PP
898	The timers are based on real time, that is, if you register an event that	933	The timers are based on real time, that is, if you register an event that
899	times out after an hour and you reset your system clock to last years	934	times out after an hour and you reset your system clock to last years
…		…
939	.Sp	974	.Sp
940	If the timer is repeating, either start it if necessary (with the repeat	975	If the timer is repeating, either start it if necessary (with the repeat
941	value), or reset the running timer to the repeat value.	976	value), or reset the running timer to the repeat value.
942	.Sp	977	.Sp
943	This sounds a bit complicated, but here is a useful and typical	978	This sounds a bit complicated, but here is a useful and typical
944	example: Imagine you have a tcp connection and you want a so-called idle	979	example: Imagine you have a tcp connection and you want a so-called
945	timeout, that is, you want to be called when there have been, say, 60	980	idle timeout, that is, you want to be called when there have been,
946	seconds of inactivity on the socket. The easiest way to do this is to	981	say, 60 seconds of inactivity on the socket. The easiest way to do
947	configure an \f(CW\(C`ev_timer\(C'\fR with after=repeat=60 and calling ev_timer_again each	982	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
948	time you successfully read or write some data. If you go into an idle	983	\&\f(CW\(C`ev_timer_again\(C'\fR each time you successfully read or write some data. If
949	state where you do not expect data to travel on the socket, you can stop	984	you go into an idle state where you do not expect data to travel on the
950	the timer, and again will automatically restart it if need be.	985	socket, you can stop the timer, and again will automatically restart it if
		986	need be.
		987	.Sp
		988	You can also ignore the \f(CW\(C`after\(C'\fR value and \f(CW\(C`ev_timer_start\(C'\fR altogether
		989	and only ever use the \f(CW\(C`repeat\(C'\fR value:
		990	.Sp
		991	.Vb 8
		992	\& ev_timer_init (timer, callback, 0., 5.);
		993	\& ev_timer_again (loop, timer);
		994	\& ...
		995	\& timer->again = 17.;
		996	\& ev_timer_again (loop, timer);
		997	\& ...
		998	\& timer->again = 10.;
		999	\& ev_timer_again (loop, timer);
		1000	.Ve
		1001	.Sp
		1002	This is more efficient then stopping/starting the timer eahc time you want
		1003	to modify its timeout value.
		1004	.IP "ev_tstamp repeat [read\-write]" 4
		1005	.IX Item "ev_tstamp repeat [read-write]"
		1006	The current \f(CW\(C`repeat\(C'\fR value. Will be used each time the watcher times out
		1007	or \f(CW\(C`ev_timer_again\(C'\fR is called and determines the next timeout (if any),
		1008	which is also when any modifications are taken into account.
951	.PP	1009	.PP
952	Example: create a timer that fires after 60 seconds.	1010	Example: create a timer that fires after 60 seconds.
953	.PP	1011	.PP
954	.Vb 5	1012	.Vb 5
955	\& static void	1013	\& static void
…		…
986	.Vb 3	1044	.Vb 3
987	\& // and in some piece of code that gets executed on any "activity":	1045	\& // and in some piece of code that gets executed on any "activity":
988	\& // reset the timeout to start ticking again at 10 seconds	1046	\& // reset the timeout to start ticking again at 10 seconds
989	\& ev_timer_again (&mytimer);	1047	\& ev_timer_again (&mytimer);
990	.Ve	1048	.Ve
991	.ie n .Sh """ev_periodic"" \- to cron or not to cron"	1049	.ie n .Sh """ev_periodic"" \- to cron or not to cron?"
992	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron"	1050	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?"
993	.IX Subsection "ev_periodic - to cron or not to cron"	1051	.IX Subsection "ev_periodic - to cron or not to cron?"
994	Periodic watchers are also timers of a kind, but they are very versatile	1052	Periodic watchers are also timers of a kind, but they are very versatile
995	(and unfortunately a bit complex).	1053	(and unfortunately a bit complex).
996	.PP	1054	.PP
997	Unlike \f(CW\(C`ev_timer\(C'\fR's, they are not based on real time (or relative time)	1055	Unlike \f(CW\(C`ev_timer\(C'\fR's, they are not based on real time (or relative time)
998	but on wallclock time (absolute time). You can tell a periodic watcher	1056	but on wallclock time (absolute time). You can tell a periodic watcher
…		…
1087	.IX Item "ev_periodic_again (loop, ev_periodic *)"	1145	.IX Item "ev_periodic_again (loop, ev_periodic *)"
1088	Simply stops and restarts the periodic watcher again. This is only useful	1146	Simply stops and restarts the periodic watcher again. This is only useful
1089	when you changed some parameters or the reschedule callback would return	1147	when you changed some parameters or the reschedule callback would return
1090	a different time than the last time it was called (e.g. in a crond like	1148	a different time than the last time it was called (e.g. in a crond like
1091	program when the crontabs have changed).	1149	program when the crontabs have changed).
		1150	.IP "ev_tstamp interval [read\-write]" 4
		1151	.IX Item "ev_tstamp interval [read-write]"
		1152	The current interval value. Can be modified any time, but changes only
		1153	take effect when the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being
		1154	called.
		1155	.IP "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read\-write]" 4
		1156	.IX Item "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]"
		1157	The current reschedule callback, or \f(CW0\fR, if this functionality is
		1158	switched off. Can be changed any time, but changes only take effect when
		1159	the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being called.
1092	.PP	1160	.PP
1093	Example: call a callback every hour, or, more precisely, whenever the	1161	Example: call a callback every hour, or, more precisely, whenever the
1094	system clock is divisible by 3600. The callback invocation times have	1162	system clock is divisible by 3600. The callback invocation times have
1095	potentially a lot of jittering, but good long-term stability.	1163	potentially a lot of jittering, but good long-term stability.
1096	.PP	1164	.PP
…		…
1132	\& struct ev_periodic hourly_tick;	1200	\& struct ev_periodic hourly_tick;
1133	\& ev_periodic_init (&hourly_tick, clock_cb,	1201	\& ev_periodic_init (&hourly_tick, clock_cb,
1134	\& fmod (ev_now (loop), 3600.), 3600., 0);	1202	\& fmod (ev_now (loop), 3600.), 3600., 0);
1135	\& ev_periodic_start (loop, &hourly_tick);	1203	\& ev_periodic_start (loop, &hourly_tick);
1136	.Ve	1204	.Ve
1137	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled"	1205	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!"
1138	.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled"	1206	.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!"
1139	.IX Subsection "ev_signal - signal me when a signal gets signalled"	1207	.IX Subsection "ev_signal - signal me when a signal gets signalled!"
1140	Signal watchers will trigger an event when the process receives a specific	1208	Signal watchers will trigger an event when the process receives a specific
1141	signal one or more times. Even though signals are very asynchronous, libev	1209	signal one or more times. Even though signals are very asynchronous, libev
1142	will try it's best to deliver signals synchronously, i.e. as part of the	1210	will try it's best to deliver signals synchronously, i.e. as part of the
1143	normal event processing, like any other event.	1211	normal event processing, like any other event.
1144	.PP	1212	.PP
…		…
1154	.IP "ev_signal_set (ev_signal *, int signum)" 4	1222	.IP "ev_signal_set (ev_signal *, int signum)" 4
1155	.IX Item "ev_signal_set (ev_signal *, int signum)"	1223	.IX Item "ev_signal_set (ev_signal *, int signum)"
1156	.PD	1224	.PD
1157	Configures the watcher to trigger on the given signal number (usually one	1225	Configures the watcher to trigger on the given signal number (usually one
1158	of the \f(CW\(C`SIGxxx\(C'\fR constants).	1226	of the \f(CW\(C`SIGxxx\(C'\fR constants).
		1227	.IP "int signum [read\-only]" 4
		1228	.IX Item "int signum [read-only]"
		1229	The signal the watcher watches out for.
1159	.ie n .Sh """ev_child"" \- wait for pid status changes"	1230	.ie n .Sh """ev_child"" \- watch out for process status changes"
1160	.el .Sh "\f(CWev_child\fP \- wait for pid status changes"	1231	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1161	.IX Subsection "ev_child - wait for pid status changes"	1232	.IX Subsection "ev_child - watch out for process status changes"
1162	Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to	1233	Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
1163	some child status changes (most typically when a child of yours dies).	1234	some child status changes (most typically when a child of yours dies).
1164	.IP "ev_child_init (ev_child *, callback, int pid)" 4	1235	.IP "ev_child_init (ev_child *, callback, int pid)" 4
1165	.IX Item "ev_child_init (ev_child *, callback, int pid)"	1236	.IX Item "ev_child_init (ev_child *, callback, int pid)"
1166	.PD 0	1237	.PD 0
…		…
1171	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look	1242	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look
1172	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see	1243	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see
1173	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems	1244	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems
1174	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the	1245	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the
1175	process causing the status change.	1246	process causing the status change.
		1247	.IP "int pid [read\-only]" 4
		1248	.IX Item "int pid [read-only]"
		1249	The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
		1250	.IP "int rpid [read\-write]" 4
		1251	.IX Item "int rpid [read-write]"
		1252	The process id that detected a status change.
		1253	.IP "int rstatus [read\-write]" 4
		1254	.IX Item "int rstatus [read-write]"
		1255	The process exit/trace status caused by \f(CW\(C`rpid\(C'\fR (see your systems
		1256	\&\f(CW\(C`waitpid\(C'\fR and \f(CW\(C`sys/wait.h\(C'\fR documentation for details).
1176	.PP	1257	.PP
1177	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.	1258	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1178	.PP	1259	.PP
1179	.Vb 5	1260	.Vb 5
1180	\& static void	1261	\& static void
…		…
1187	.Vb 3	1268	.Vb 3
1188	\& struct ev_signal signal_watcher;	1269	\& struct ev_signal signal_watcher;
1189	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1270	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1190	\& ev_signal_start (loop, &sigint_cb);	1271	\& ev_signal_start (loop, &sigint_cb);
1191	.Ve	1272	.Ve
		1273	.ie n .Sh """ev_stat"" \- did the file attributes just change?"
		1274	.el .Sh "\f(CWev_stat\fP \- did the file attributes just change?"
		1275	.IX Subsection "ev_stat - did the file attributes just change?"
		1276	This watches a filesystem path for attribute changes. That is, it calls
		1277	\&\f(CW\(C`stat\(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed
		1278	compared to the last time, invoking the callback if it did.
		1279	.PP
		1280	The path does not need to exist: changing from \(L"path exists\(R" to \*(L"path does
		1281	not exist\(R" is a status change like any other. The condition \(L"path does
		1282	not exist\(R" is signified by the \f(CW\(C`st_nlink\*(C'\fR field being zero (which is
		1283	otherwise always forced to be at least one) and all the other fields of
		1284	the stat buffer having unspecified contents.
		1285	.PP
		1286	Since there is no standard to do this, the portable implementation simply
		1287	calls \f(CW\(C`stat (2)\(C'\fR regulalry on the path to see if it changed somehow. You
		1288	can specify a recommended polling interval for this case. If you specify
		1289	a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
		1290	unspecified default\fR value will be used (which you can expect to be around
		1291	five seconds, although this might change dynamically). Libev will also
		1292	impose a minimum interval which is currently around \f(CW0.1\fR, but thats
		1293	usually overkill.
		1294	.PP
		1295	This watcher type is not meant for massive numbers of stat watchers,
		1296	as even with OS-supported change notifications, this can be
		1297	resource\-intensive.
		1298	.PP
		1299	At the time of this writing, no specific \s-1OS\s0 backends are implemented, but
		1300	if demand increases, at least a kqueue and inotify backend will be added.
		1301	.IP "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)" 4
		1302	.IX Item "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)"
		1303	.PD 0
		1304	.IP "ev_stat_set (ev_stat , const char path, ev_tstamp interval)" 4
		1305	.IX Item "ev_stat_set (ev_stat , const char path, ev_tstamp interval)"
		1306	.PD
		1307	Configures the watcher to wait for status changes of the given
		1308	\&\f(CW\(C`path\(C'\fR. The \f(CW\(C`interval\(C'\fR is a hint on how quickly a change is expected to
		1309	be detected and should normally be specified as \f(CW0\fR to let libev choose
		1310	a suitable value. The memory pointed to by \f(CW\(C`path\(C'\fR must point to the same
		1311	path for as long as the watcher is active.
		1312	.Sp
		1313	The callback will be receive \f(CW\(C`EV_STAT\(C'\fR when a change was detected,
		1314	relative to the attributes at the time the watcher was started (or the
		1315	last change was detected).
		1316	.IP "ev_stat_stat (ev_stat *)" 4
		1317	.IX Item "ev_stat_stat (ev_stat *)"
		1318	Updates the stat buffer immediately with new values. If you change the
		1319	watched path in your callback, you could call this fucntion to avoid
		1320	detecting this change (while introducing a race condition). Can also be
		1321	useful simply to find out the new values.
		1322	.IP "ev_statdata attr [read\-only]" 4
		1323	.IX Item "ev_statdata attr [read-only]"
		1324	The most-recently detected attributes of the file. Although the type is of
		1325	\&\f(CW\(C`ev_statdata\(C'\fR, this is usually the (or one of the) \f(CW\(C`struct stat\(C'\fR types
		1326	suitable for your system. If the \f(CW\(C`st_nlink\(C'\fR member is \f(CW0\fR, then there
		1327	was some error while \f(CW\(C`stat\(C'\fRing the file.
		1328	.IP "ev_statdata prev [read\-only]" 4
		1329	.IX Item "ev_statdata prev [read-only]"
		1330	The previous attributes of the file. The callback gets invoked whenever
		1331	\&\f(CW\(C`prev\(C'\fR != \f(CW\(C`attr\(C'\fR.
		1332	.IP "ev_tstamp interval [read\-only]" 4
		1333	.IX Item "ev_tstamp interval [read-only]"
		1334	The specified interval.
		1335	.IP "const char *path [read\-only]" 4
		1336	.IX Item "const char *path [read-only]"
		1337	The filesystem path that is being watched.
		1338	.PP
		1339	Example: Watch \f(CW\(C`/etc/passwd\(C'\fR for attribute changes.
		1340	.PP
		1341	.Vb 15
		1342	\& static void
		1343	\& passwd_cb (struct ev_loop loop, ev_stat w, int revents)
		1344	\& {
		1345	\& /* /etc/passwd changed in some way */
		1346	\& if (w->attr.st_nlink)
		1347	\& {
		1348	\& printf ("passwd current size %ld\en", (long)w->attr.st_size);
		1349	\& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime);
		1350	\& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime);
		1351	\& }
		1352	\& else
		1353	\& /* you shalt not abuse printf for puts */
		1354	\& puts ("wow, /etc/passwd is not there, expect problems. "
		1355	\& "if this is windows, they already arrived\en");
		1356	\& }
		1357	.Ve
		1358	.PP
		1359	.Vb 2
		1360	\& ...
		1361	\& ev_stat passwd;
		1362	.Ve
		1363	.PP
		1364	.Vb 2
		1365	\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
		1366	\& ev_stat_start (loop, &passwd);
		1367	.Ve
1192	.ie n .Sh """ev_idle"" \- when you've got nothing better to do"	1368	.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
1193	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do"	1369	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
1194	.IX Subsection "ev_idle - when you've got nothing better to do"	1370	.IX Subsection "ev_idle - when you've got nothing better to do..."
1195	Idle watchers trigger events when there are no other events are pending	1371	Idle watchers trigger events when there are no other events are pending
1196	(prepare, check and other idle watchers do not count). That is, as long	1372	(prepare, check and other idle watchers do not count). That is, as long
1197	as your process is busy handling sockets or timeouts (or even signals,	1373	as your process is busy handling sockets or timeouts (or even signals,
1198	imagine) it will not be triggered. But when your process is idle all idle	1374	imagine) it will not be triggered. But when your process is idle all idle
1199	watchers are being called again and again, once per event loop iteration \-	1375	watchers are being called again and again, once per event loop iteration \-
…		…
1229	.Vb 3	1405	.Vb 3
1230	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1406	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1231	\& ev_idle_init (idle_watcher, idle_cb);	1407	\& ev_idle_init (idle_watcher, idle_cb);
1232	\& ev_idle_start (loop, idle_cb);	1408	\& ev_idle_start (loop, idle_cb);
1233	.Ve	1409	.Ve
1234	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop"	1410	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!"
1235	.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop"	1411	.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!"
1236	.IX Subsection "ev_prepare and ev_check - customise your event loop"	1412	.IX Subsection "ev_prepare and ev_check - customise your event loop!"
1237	Prepare and check watchers are usually (but not always) used in tandem:	1413	Prepare and check watchers are usually (but not always) used in tandem:
1238	prepare watchers get invoked before the process blocks and check watchers	1414	prepare watchers get invoked before the process blocks and check watchers
1239	afterwards.	1415	afterwards.
1240	.PP	1416	.PP
		1417	You \fImust not\fR call \f(CW\(C`ev_loop\(C'\fR or similar functions that enter
		1418	the current event loop from either \f(CW\(C`ev_prepare\(C'\fR or \f(CW\(C`ev_check\(C'\fR
		1419	watchers. Other loops than the current one are fine, however. The
		1420	rationale behind this is that you do not need to check for recursion in
		1421	those watchers, i.e. the sequence will always be \f(CW\(C`ev_prepare\(C'\fR, blocking,
		1422	\&\f(CW\(C`ev_check\(C'\fR so if you have one watcher of each kind they will always be
		1423	called in pairs bracketing the blocking call.
		1424	.PP
1241	Their main purpose is to integrate other event mechanisms into libev and	1425	Their main purpose is to integrate other event mechanisms into libev and
1242	their use is somewhat advanced. This could be used, for example, to track	1426	their use is somewhat advanced. This could be used, for example, to track
1243	variable changes, implement your own watchers, integrate net-snmp or a	1427	variable changes, implement your own watchers, integrate net-snmp or a
1244	coroutine library and lots more.	1428	coroutine library and lots more. They are also occasionally useful if
		1429	you cache some data and want to flush it before blocking (for example,
		1430	in X programs you might want to do an \f(CW\(C`XFlush ()\(C'\fR in an \f(CW\(C`ev_prepare\(C'\fR
		1431	watcher).
1245	.PP	1432	.PP
1246	This is done by examining in each prepare call which file descriptors need	1433	This is done by examining in each prepare call which file descriptors need
1247	to be watched by the other library, registering \f(CW\(C`ev_io\(C'\fR watchers for	1434	to be watched by the other library, registering \f(CW\(C`ev_io\(C'\fR watchers for
1248	them and starting an \f(CW\(C`ev_timer\(C'\fR watcher for any timeouts (many libraries	1435	them and starting an \f(CW\(C`ev_timer\(C'\fR watcher for any timeouts (many libraries
1249	provide just this functionality). Then, in the check watcher you check for	1436	provide just this functionality). Then, in the check watcher you check for
…		…
1268	.PD	1455	.PD
1269	Initialises and configures the prepare or check watcher \- they have no	1456	Initialises and configures the prepare or check watcher \- they have no
1270	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR	1457	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR
1271	macros, but using them is utterly, utterly and completely pointless.	1458	macros, but using them is utterly, utterly and completely pointless.
1272	.PP	1459	.PP
1273	Example: TODO.	1460	Example: To include a library such as adns, you would add \s-1IO\s0 watchers
		1461	and a timeout watcher in a prepare handler, as required by libadns, and
		1462	in a check watcher, destroy them and call into libadns. What follows is
		1463	pseudo-code only of course:
		1464	.PP
		1465	.Vb 2
		1466	\& static ev_io iow [nfd];
		1467	\& static ev_timer tw;
		1468	.Ve
		1469	.PP
		1470	.Vb 9
		1471	\& static void
		1472	\& io_cb (ev_loop loop, ev_io w, int revents)
		1473	\& {
		1474	\& // set the relevant poll flags
		1475	\& // could also call adns_processreadable etc. here
		1476	\& struct pollfd fd = (struct pollfd )w->data;
		1477	\& if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1478	\& if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1479	\& }
		1480	.Ve
		1481	.PP
		1482	.Vb 7
		1483	\& // create io watchers for each fd and a timer before blocking
		1484	\& static void
		1485	\& adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
		1486	\& {
		1487	\& int timeout = 3600000;truct pollfd fds [nfd];
		1488	\& // actual code will need to loop here and realloc etc.
		1489	\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
		1490	.Ve
		1491	.PP
		1492	.Vb 3
		1493	\& /* the callback is illegal, but won't be called as we stop during check */
		1494	\& ev_timer_init (&tw, 0, timeout * 1e-3);
		1495	\& ev_timer_start (loop, &tw);
		1496	.Ve
		1497	.PP
		1498	.Vb 6
		1499	\& // create on ev_io per pollfd
		1500	\& for (int i = 0; i < nfd; ++i)
		1501	\& {
		1502	\& ev_io_init (iow + i, io_cb, fds [i].fd,
		1503	\& ((fds [i].events & POLLIN ? EV_READ : 0)
		1504	\& \| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
		1505	.Ve
		1506	.PP
		1507	.Vb 5
		1508	\& fds [i].revents = 0;
		1509	\& iow [i].data = fds + i;
		1510	\& ev_io_start (loop, iow + i);
		1511	\& }
		1512	\& }
		1513	.Ve
		1514	.PP
		1515	.Vb 5
		1516	\& // stop all watchers after blocking
		1517	\& static void
		1518	\& adns_check_cb (ev_loop loop, ev_check w, int revents)
		1519	\& {
		1520	\& ev_timer_stop (loop, &tw);
		1521	.Ve
		1522	.PP
		1523	.Vb 2
		1524	\& for (int i = 0; i < nfd; ++i)
		1525	\& ev_io_stop (loop, iow + i);
		1526	.Ve
		1527	.PP
		1528	.Vb 2
		1529	\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1530	\& }
		1531	.Ve
1274	.ie n .Sh """ev_embed"" \- when one backend isn't enough"	1532	.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1275	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough"	1533	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1276	.IX Subsection "ev_embed - when one backend isn't enough"	1534	.IX Subsection "ev_embed - when one backend isn't enough..."
1277	This is a rather advanced watcher type that lets you embed one event loop	1535	This is a rather advanced watcher type that lets you embed one event loop
1278	into another (currently only \f(CW\(C`ev_io\(C'\fR events are supported in the embedded	1536	into another (currently only \f(CW\(C`ev_io\(C'\fR events are supported in the embedded
1279	loop, other types of watchers might be handled in a delayed or incorrect	1537	loop, other types of watchers might be handled in a delayed or incorrect
1280	fashion and must not be used).	1538	fashion and must not be used).
1281	.PP	1539	.PP
…		…
1361	.IP "ev_embed_sweep (loop, ev_embed *)" 4	1619	.IP "ev_embed_sweep (loop, ev_embed *)" 4
1362	.IX Item "ev_embed_sweep (loop, ev_embed *)"	1620	.IX Item "ev_embed_sweep (loop, ev_embed *)"
1363	Make a single, non-blocking sweep over the embedded loop. This works	1621	Make a single, non-blocking sweep over the embedded loop. This works
1364	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most	1622	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most
1365	apropriate way for embedded loops.	1623	apropriate way for embedded loops.
		1624	.IP "struct ev_loop *loop [read\-only]" 4
		1625	.IX Item "struct ev_loop *loop [read-only]"
		1626	The embedded event loop.
		1627	.ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork"
		1628	.el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
		1629	.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
		1630	Fork watchers are called when a \f(CW\(C`fork ()\(C'\fR was detected (usually because
		1631	whoever is a good citizen cared to tell libev about it by calling
		1632	\&\f(CW\(C`ev_default_fork\(C'\fR or \f(CW\(C`ev_loop_fork\(C'\fR). The invocation is done before the
		1633	event loop blocks next and before \f(CW\(C`ev_check\(C'\fR watchers are being called,
		1634	and only in the child after the fork. If whoever good citizen calling
		1635	\&\f(CW\(C`ev_default_fork\(C'\fR cheats and calls it in the wrong process, the fork
		1636	handlers will be invoked, too, of course.
		1637	.IP "ev_fork_init (ev_signal *, callback)" 4
		1638	.IX Item "ev_fork_init (ev_signal *, callback)"
		1639	Initialises and configures the fork watcher \- it has no parameters of any
		1640	kind. There is a \f(CW\(C`ev_fork_set\(C'\fR macro, but using it is utterly pointless,
		1641	believe me.
1366	.SH "OTHER FUNCTIONS"	1642	.SH "OTHER FUNCTIONS"
1367	.IX Header "OTHER FUNCTIONS"	1643	.IX Header "OTHER FUNCTIONS"
1368	There are some other functions of possible interest. Described. Here. Now.	1644	There are some other functions of possible interest. Described. Here. Now.
1369	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4	1645	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
1370	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"	1646	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
…		…
1509	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.	1785	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.
1510	.ie n .IP "w\->sweep () ""ev::embed"" only" 4	1786	.ie n .IP "w\->sweep () ""ev::embed"" only" 4
1511	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4	1787	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
1512	.IX Item "w->sweep () ev::embed only"	1788	.IX Item "w->sweep () ev::embed only"
1513	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.	1789	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.
		1790	.ie n .IP "w\->update () ""ev::stat"" only" 4
		1791	.el .IP "w\->update () \f(CWev::stat\fR only" 4
		1792	.IX Item "w->update () ev::stat only"
		1793	Invokes \f(CW\(C`ev_stat_stat\(C'\fR.
1514	.RE	1794	.RE
1515	.RS 4	1795	.RS 4
1516	.RE	1796	.RE
1517	.PP	1797	.PP
1518	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in	1798	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
…		…
1535	\& : io (this, &myclass::io_cb),	1815	\& : io (this, &myclass::io_cb),
1536	\& idle (this, &myclass::idle_cb)	1816	\& idle (this, &myclass::idle_cb)
1537	\& {	1817	\& {
1538	\& io.start (fd, ev::READ);	1818	\& io.start (fd, ev::READ);
1539	\& }	1819	\& }
		1820	.Ve
		1821	.SH "MACRO MAGIC"
		1822	.IX Header "MACRO MAGIC"
		1823	Libev can be compiled with a variety of options, the most fundemantal is
		1824	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR. This option determines wether (most) functions and
		1825	callbacks have an initial \f(CW\(C`struct ev_loop \*(C'\fR argument.
		1826	.PP
		1827	To make it easier to write programs that cope with either variant, the
		1828	following macros are defined:
		1829	.ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4
		1830	.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
		1831	.IX Item "EV_A, EV_A_"
		1832	This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
		1833	loop argument\(R"). The \f(CW\(C`EV_A\*(C'\fR form is used when this is the sole argument,
		1834	\&\f(CW\(C`EV_A_\(C'\fR is used when other arguments are following. Example:
		1835	.Sp
		1836	.Vb 3
		1837	\& ev_unref (EV_A);
		1838	\& ev_timer_add (EV_A_ watcher);
		1839	\& ev_loop (EV_A_ 0);
		1840	.Ve
		1841	.Sp
		1842	It assumes the variable \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR is in scope,
		1843	which is often provided by the following macro.
		1844	.ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4
		1845	.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
		1846	.IX Item "EV_P, EV_P_"
		1847	This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
		1848	loop parameter\(R"). The \f(CW\(C`EV_P\*(C'\fR form is used when this is the sole parameter,
		1849	\&\f(CW\(C`EV_P_\(C'\fR is used when other parameters are following. Example:
		1850	.Sp
		1851	.Vb 2
		1852	\& // this is how ev_unref is being declared
		1853	\& static void ev_unref (EV_P);
		1854	.Ve
		1855	.Sp
		1856	.Vb 2
		1857	\& // this is how you can declare your typical callback
		1858	\& static void cb (EV_P_ ev_timer *w, int revents)
		1859	.Ve
		1860	.Sp
		1861	It declares a parameter \f(CW\(C`loop\(C'\fR of type \f(CW\(C`struct ev_loop \*(C'\fR, quite
		1862	suitable for use with \f(CW\(C`EV_A\(C'\fR.
		1863	.ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4
		1864	.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
		1865	.IX Item "EV_DEFAULT, EV_DEFAULT_"
		1866	Similar to the other two macros, this gives you the value of the default
		1867	loop, if multiple loops are supported (\(L"ev loop default\(R").
		1868	.PP
		1869	Example: Declare and initialise a check watcher, working regardless of
		1870	wether multiple loops are supported or not.
		1871	.PP
		1872	.Vb 5
		1873	\& static void
		1874	\& check_cb (EV_P_ ev_timer *w, int revents)
		1875	\& {
		1876	\& ev_check_stop (EV_A_ w);
		1877	\& }
		1878	.Ve
		1879	.PP
		1880	.Vb 4
		1881	\& ev_check check;
		1882	\& ev_check_init (&check, check_cb);
		1883	\& ev_check_start (EV_DEFAULT_ &check);
		1884	\& ev_loop (EV_DEFAULT_ 0);
1540	.Ve	1885	.Ve
1541	.SH "EMBEDDING"	1886	.SH "EMBEDDING"
1542	.IX Header "EMBEDDING"	1887	.IX Header "EMBEDDING"
1543	Libev can (and often is) directly embedded into host	1888	Libev can (and often is) directly embedded into host
1544	applications. Examples of applications that embed it include the Deliantra	1889	applications. Examples of applications that embed it include the Deliantra
…		…
1593	.Vb 1	1938	.Vb 1
1594	\& ev_win32.c required on win32 platforms only	1939	\& ev_win32.c required on win32 platforms only
1595	.Ve	1940	.Ve
1596	.PP	1941	.PP
1597	.Vb 5	1942	.Vb 5
1598	\& ev_select.c only when select backend is enabled (which is is by default)	1943	\& ev_select.c only when select backend is enabled (which is by default)
1599	\& ev_poll.c only when poll backend is enabled (disabled by default)	1944	\& ev_poll.c only when poll backend is enabled (disabled by default)
1600	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)	1945	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
1601	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	1946	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1602	\& ev_port.c only when the solaris port backend is enabled (disabled by default)	1947	\& ev_port.c only when the solaris port backend is enabled (disabled by default)
1603	.Ve	1948	.Ve
1604	.PP	1949	.PP
1605	\&\fIev.c\fR includes the backend files directly when enabled, so you only need	1950	\&\fIev.c\fR includes the backend files directly when enabled, so you only need
1606	to compile a single file.	1951	to compile this single file.
1607	.PP	1952	.PP
1608	\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR	1953	\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR
1609	.IX Subsection "LIBEVENT COMPATIBILITY API"	1954	.IX Subsection "LIBEVENT COMPATIBILITY API"
1610	.PP	1955	.PP
1611	To include the libevent compatibility \s-1API\s0, also include:	1956	To include the libevent compatibility \s-1API\s0, also include:
…		…
1632	\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR	1977	\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR
1633	.IX Subsection "AUTOCONF SUPPORT"	1978	.IX Subsection "AUTOCONF SUPPORT"
1634	.PP	1979	.PP
1635	Instead of using \f(CW\(C`EV_STANDALONE=1\(C'\fR and providing your config in	1980	Instead of using \f(CW\(C`EV_STANDALONE=1\(C'\fR and providing your config in
1636	whatever way you want, you can also \f(CW\(C`m4_include([libev.m4])\(C'\fR in your	1981	whatever way you want, you can also \f(CW\(C`m4_include([libev.m4])\(C'\fR in your
1637	\&\fIconfigure.ac\fR and leave \f(CW\(C`EV_STANDALONE\(C'\fR off. \fIev.c\fR will then include	1982	\&\fIconfigure.ac\fR and leave \f(CW\(C`EV_STANDALONE\(C'\fR undefined. \fIev.c\fR will then
1638	\&\fIconfig.h\fR and configure itself accordingly.	1983	include \fIconfig.h\fR and configure itself accordingly.
1639	.PP	1984	.PP
1640	For this of course you need the m4 file:	1985	For this of course you need the m4 file:
1641	.PP	1986	.PP
1642	.Vb 1	1987	.Vb 1
1643	\& libev.m4	1988	\& libev.m4
…		…
1751	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions	2096	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
1752	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create	2097	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create
1753	additional independent event loops. Otherwise there will be no support	2098	additional independent event loops. Otherwise there will be no support
1754	for multiple event loops and there is no first event loop pointer	2099	for multiple event loops and there is no first event loop pointer
1755	argument. Instead, all functions act on the single default loop.	2100	argument. Instead, all functions act on the single default loop.
1756	.IP "\s-1EV_PERIODICS\s0" 4	2101	.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
1757	.IX Item "EV_PERIODICS"	2102	.IX Item "EV_PERIODIC_ENABLE"
1758	If undefined or defined to be \f(CW1\fR, then periodic timers are supported,	2103	If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
1759	otherwise not. This saves a few kb of code.	2104	defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
		2105	code.
		2106	.IP "\s-1EV_EMBED_ENABLE\s0" 4
		2107	.IX Item "EV_EMBED_ENABLE"
		2108	If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
		2109	defined to be \f(CW0\fR, then they are not.
		2110	.IP "\s-1EV_STAT_ENABLE\s0" 4
		2111	.IX Item "EV_STAT_ENABLE"
		2112	If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
		2113	defined to be \f(CW0\fR, then they are not.
		2114	.IP "\s-1EV_FORK_ENABLE\s0" 4
		2115	.IX Item "EV_FORK_ENABLE"
		2116	If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If
		2117	defined to be \f(CW0\fR, then they are not.
		2118	.IP "\s-1EV_MINIMAL\s0" 4
		2119	.IX Item "EV_MINIMAL"
		2120	If you need to shave off some kilobytes of code at the expense of some
		2121	speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
		2122	some inlining decisions, saves roughly 30% codesize of amd64.
1760	.IP "\s-1EV_COMMON\s0" 4	2123	.IP "\s-1EV_COMMON\s0" 4
1761	.IX Item "EV_COMMON"	2124	.IX Item "EV_COMMON"
1762	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining	2125	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining
1763	this macro to a something else you can include more and other types of	2126	this macro to a something else you can include more and other types of
1764	members. You have to define it each time you include one of the files,	2127	members. You have to define it each time you include one of the files,
…		…
1769	.Vb 3	2132	.Vb 3
1770	\& #define EV_COMMON \e	2133	\& #define EV_COMMON \e
1771	\& SV self; / contains this struct */ \e	2134	\& SV self; / contains this struct */ \e
1772	\& SV cb_sv, fh /* note no trailing ";" */	2135	\& SV cb_sv, fh /* note no trailing ";" */
1773	.Ve	2136	.Ve
1774	.IP "\s-1EV_CB_DECLARE\s0(type)" 4	2137	.IP "\s-1EV_CB_DECLARE\s0 (type)" 4
1775	.IX Item "EV_CB_DECLARE(type)"	2138	.IX Item "EV_CB_DECLARE (type)"
1776	.PD 0	2139	.PD 0
1777	.IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4	2140	.IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4
1778	.IX Item "EV_CB_INVOKE(watcher,revents)"	2141	.IX Item "EV_CB_INVOKE (watcher, revents)"
1779	.IP "ev_set_cb(ev,cb)" 4	2142	.IP "ev_set_cb (ev, cb)" 4
1780	.IX Item "ev_set_cb(ev,cb)"	2143	.IX Item "ev_set_cb (ev, cb)"
1781	.PD	2144	.PD
1782	Can be used to change the callback member declaration in each watcher,	2145	Can be used to change the callback member declaration in each watcher,
1783	and the way callbacks are invoked and set. Must expand to a struct member	2146	and the way callbacks are invoked and set. Must expand to a struct member
1784	definition and a statement, respectively. See the \fIev.v\fR header file for	2147	definition and a statement, respectively. See the \fIev.v\fR header file for
1785	their default definitions. One possible use for overriding these is to	2148	their default definitions. One possible use for overriding these is to
1786	avoid the ev_loop pointer as first argument in all cases, or to use method	2149	avoid the \f(CW\(C`struct ev_loop \*(C'\fR as first argument in all cases, or to use
1787	calls instead of plain function calls in \*(C+.	2150	method calls instead of plain function calls in \*(C+.
1788	.Sh "\s-1EXAMPLES\s0"	2151	.Sh "\s-1EXAMPLES\s0"
1789	.IX Subsection "EXAMPLES"	2152	.IX Subsection "EXAMPLES"
1790	For a real-world example of a program the includes libev	2153	For a real-world example of a program the includes libev
1791	verbatim, you can have a look at the \s-1EV\s0 perl module	2154	verbatim, you can have a look at the \s-1EV\s0 perl module
1792	(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in	2155	(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
…		…
1813	.Sp	2176	.Sp
1814	.Vb 2	2177	.Vb 2
1815	\& #include "ev_cpp.h"	2178	\& #include "ev_cpp.h"
1816	\& #include "ev.c"	2179	\& #include "ev.c"
1817	.Ve	2180	.Ve
		2181	.SH "COMPLEXITIES"
		2182	.IX Header "COMPLEXITIES"
		2183	In this section the complexities of (many of) the algorithms used inside
		2184	libev will be explained. For complexity discussions about backends see the
		2185	documentation for \f(CW\(C`ev_default_init\(C'\fR.
		2186	.RS 4
		2187	.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
		2188	.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
		2189	.PD 0
		2190	.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4
		2191	.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
		2192	.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
		2193	.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
		2194	.IP "Stopping check/prepare/idle watchers: O(1)" 4
		2195	.IX Item "Stopping check/prepare/idle watchers: O(1)"
		2196	.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4
		2197	.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))"
		2198	.IP "Finding the next timer per loop iteration: O(1)" 4
		2199	.IX Item "Finding the next timer per loop iteration: O(1)"
		2200	.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
		2201	.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
		2202	.IP "Activating one watcher: O(1)" 4
		2203	.IX Item "Activating one watcher: O(1)"
		2204	.RE
		2205	.RS 4
		2206	.PD
1818	.SH "AUTHOR"	2207	.SH "AUTHOR"
1819	.IX Header "AUTHOR"	2208	.IX Header "AUTHOR"
1820	Marc Lehmann <libev@schmorp.de>.	2209	Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.3 (file contents):
Revision 1.16 by root, Sat Nov 24 10:19:14 2007 UTC vs.
Revision 1.24 by root, Tue Nov 27 10:59:10 2007 UTC