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

Comparing libev/ev.3 (file contents):
Revision 1.12 by root, Sat Nov 24 07:20:42 2007 UTC vs.
Revision 1.17 by root, Sat Nov 24 16:31:45 2007 UTC

…		…
717	Libev will usually signal a few \(L"dummy\(R" events together with an error,	717	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	718	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	719	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	720	with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded
721	programs, though, so beware.	721	programs, though, so beware.
722	.Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"	722	.Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"
723	.IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS"	723	.IX Subsection "GENERIC WATCHER FUNCTIONS"
724	In the following description, \f(CW\(C`TYPE\(C'\fR stands for the watcher type,	724	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.	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.
726	.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4	726	.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
727	.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4	727	.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4
728	.IX Item "ev_init (ev_TYPE *watcher, callback)"	728	.IX Item "ev_init (ev_TYPE *watcher, callback)"
…		…
734	which rolls both calls into one.	734	which rolls both calls into one.
735	.Sp	735	.Sp
736	You can reinitialise a watcher at any time as long as it has been stopped	736	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.	737	(or never started) and there are no pending events outstanding.
738	.Sp	738	.Sp
739	The callbakc is always of type \f(CW\(C`void ()(ev_loop loop, ev_TYPE watcher,	739	The callback is always of type \f(CW\(C`void ()(ev_loop loop, ev_TYPE watcher,
740	int revents)\*(C'\fR.	740	int revents)\*(C'\fR.
741	.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4	741	.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4
742	.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4	742	.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4
743	.IX Item "ev_TYPE_set (ev_TYPE *, [args])"	743	.IX Item "ev_TYPE_set (ev_TYPE *, [args])"
744	This macro initialises the type-specific parts of a watcher. You need to	744	This macro initialises the type-specific parts of a watcher. You need to
…		…
822	have been omitted....	822	have been omitted....
823	.SH "WATCHER TYPES"	823	.SH "WATCHER TYPES"
824	.IX Header "WATCHER TYPES"	824	.IX Header "WATCHER TYPES"
825	This section describes each watcher in detail, but will not repeat	825	This section describes each watcher in detail, but will not repeat
826	information given in the last section.	826	information given in the last section.
827	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable"	827	.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"	828	.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"	829	.IX Subsection "ev_io - is this file descriptor readable or writable?"
830	I/O watchers check whether a file descriptor is readable or writable	830	I/O watchers check whether a file descriptor is readable or writable
831	in each iteration of the event loop (This behaviour is called	831	in each iteration of the event loop, or, more precisely, when reading
832	level-triggering because you keep receiving events as long as the	832	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	833	some data. This behaviour is called level-triggering because you keep
834	act on the event and neither want to receive future events).	834	receiving events as long as the condition persists. Remember you can stop
		835	the watcher if you don't want to act on the event and neither want to
		836	receive future events.
835	.PP	837	.PP
836	In general you can register as many read and/or write event watchers per	838	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	839	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	840	descriptors to non-blocking mode is also usually a good idea (but not
839	required if you know what you are doing).	841	required if you know what you are doing).
840	.PP	842	.PP
841	You have to be careful with dup'ed file descriptors, though. Some backends	843	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	844	(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	845	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	846	to the same underlying file/socket/etc. description (that is, they share
845	the same underlying \(L"file open\(R").	847	the same underlying \(L"file open\(R").
846	.PP	848	.PP
847	If you must do this, then force the use of a known-to-be-good backend	849	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	850	(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).	851	\&\f(CW\(C`EVBACKEND_POLL\(C'\fR).
		852	.PP
		853	Another thing you have to watch out for is that it is quite easy to
		854	receive \(L"spurious\(R" readyness notifications, that is your callback might
		855	be called with \f(CW\(C`EV_READ\(C'\fR but a subsequent \f(CW\(C`read\(C'\fR(2) will actually block
		856	because there is no data. Not only are some backends known to create a
		857	lot of those (for example solaris ports), it is very easy to get into
		858	this situation even with a relatively standard program structure. Thus
		859	it is best to always use non-blocking I/O: An extra \f(CW\(C`read\(C'\fR(2) returning
		860	\&\f(CW\(C`EAGAIN\(C'\fR is far preferable to a program hanging until some data arrives.
		861	.PP
		862	If you cannot run the fd in non-blocking mode (for example you should not
		863	play around with an Xlib connection), then you have to seperately re-test
		864	wether a file descriptor is really ready with a known-to-be good interface
		865	such as poll (fortunately in our Xlib example, Xlib already does this on
		866	its own, so its quite safe to use).
850	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4	867	.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)"	868	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
852	.PD 0	869	.PD 0
853	.IP "ev_io_set (ev_io *, int fd, int events)" 4	870	.IP "ev_io_set (ev_io *, int fd, int events)" 4
854	.IX Item "ev_io_set (ev_io *, int fd, int events)"	871	.IX Item "ev_io_set (ev_io *, int fd, int events)"
855	.PD	872	.PD
856	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The fd is the file descriptor to rceeive	873	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 \|	874	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.	875	\&\f(CW\(C`EV_READ \| EV_WRITE\(C'\fR to receive the given events.
859	.Sp
860	Please note that most of the more scalable backend mechanisms (for example
861	epoll and solaris ports) can result in spurious readyness notifications
862	for file descriptors, so you practically need to use non-blocking I/O (and
863	treat callback invocation as hint only), or retest separately with a safe
864	interface before doing I/O (XLib can do this), or force the use of either
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	876	.PP
871	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well	877	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	878	readable, but only once. Since it is likely line\-buffered, you could
873	attempt to read a whole line in the callback:	879	attempt to read a whole line in the callback:
874	.PP	880	.PP
…		…
887	\& struct ev_io stdin_readable;	893	\& struct ev_io stdin_readable;
888	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	894	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
889	\& ev_io_start (loop, &stdin_readable);	895	\& ev_io_start (loop, &stdin_readable);
890	\& ev_loop (loop, 0);	896	\& ev_loop (loop, 0);
891	.Ve	897	.Ve
892	.ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts"	898	.ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts"
893	.el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts"	899	.el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts"
894	.IX Subsection "ev_timer - relative and optionally recurring timeouts"	900	.IX Subsection "ev_timer - relative and optionally repeating timeouts"
895	Timer watchers are simple relative timers that generate an event after a	901	Timer watchers are simple relative timers that generate an event after a
896	given time, and optionally repeating in regular intervals after that.	902	given time, and optionally repeating in regular intervals after that.
897	.PP	903	.PP
898	The timers are based on real time, that is, if you register an event that	904	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	905	times out after an hour and you reset your system clock to last years
…		…
986	.Vb 3	992	.Vb 3
987	\& // and in some piece of code that gets executed on any "activity":	993	\& // and in some piece of code that gets executed on any "activity":
988	\& // reset the timeout to start ticking again at 10 seconds	994	\& // reset the timeout to start ticking again at 10 seconds
989	\& ev_timer_again (&mytimer);	995	\& ev_timer_again (&mytimer);
990	.Ve	996	.Ve
991	.ie n .Sh """ev_periodic"" \- to cron or not to cron"	997	.ie n .Sh """ev_periodic"" \- to cron or not to cron?"
992	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron"	998	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?"
993	.IX Subsection "ev_periodic - to cron or not to cron"	999	.IX Subsection "ev_periodic - to cron or not to cron?"
994	Periodic watchers are also timers of a kind, but they are very versatile	1000	Periodic watchers are also timers of a kind, but they are very versatile
995	(and unfortunately a bit complex).	1001	(and unfortunately a bit complex).
996	.PP	1002	.PP
997	Unlike \f(CW\(C`ev_timer\(C'\fR's, they are not based on real time (or relative time)	1003	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	1004	but on wallclock time (absolute time). You can tell a periodic watcher
999	to trigger \(L"at\(R" some specific point in time. For example, if you tell a	1005	to trigger \(L"at\(R" some specific point in time. For example, if you tell a
1000	periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now ()	1006	periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now ()
1001	+ 10.>) and then reset your system clock to the last year, then it will	1007	+ 10.\*(C'\fR) and then reset your system clock to the last year, then it will
1002	take a year to trigger the event (unlike an \f(CW\(C`ev_timer\(C'\fR, which would trigger	1008	take a year to trigger the event (unlike an \f(CW\(C`ev_timer\(C'\fR, which would trigger
1003	roughly 10 seconds later and of course not if you reset your system time	1009	roughly 10 seconds later and of course not if you reset your system time
1004	again).	1010	again).
1005	.PP	1011	.PP
1006	They can also be used to implement vastly more complex timers, such as	1012	They can also be used to implement vastly more complex timers, such as
…		…
1132	\& struct ev_periodic hourly_tick;	1138	\& struct ev_periodic hourly_tick;
1133	\& ev_periodic_init (&hourly_tick, clock_cb,	1139	\& ev_periodic_init (&hourly_tick, clock_cb,
1134	\& fmod (ev_now (loop), 3600.), 3600., 0);	1140	\& fmod (ev_now (loop), 3600.), 3600., 0);
1135	\& ev_periodic_start (loop, &hourly_tick);	1141	\& ev_periodic_start (loop, &hourly_tick);
1136	.Ve	1142	.Ve
1137	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled"	1143	.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"	1144	.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"	1145	.IX Subsection "ev_signal - signal me when a signal gets signalled!"
1140	Signal watchers will trigger an event when the process receives a specific	1146	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	1147	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	1148	will try it's best to deliver signals synchronously, i.e. as part of the
1143	normal event processing, like any other event.	1149	normal event processing, like any other event.
1144	.PP	1150	.PP
…		…
1154	.IP "ev_signal_set (ev_signal *, int signum)" 4	1160	.IP "ev_signal_set (ev_signal *, int signum)" 4
1155	.IX Item "ev_signal_set (ev_signal *, int signum)"	1161	.IX Item "ev_signal_set (ev_signal *, int signum)"
1156	.PD	1162	.PD
1157	Configures the watcher to trigger on the given signal number (usually one	1163	Configures the watcher to trigger on the given signal number (usually one
1158	of the \f(CW\(C`SIGxxx\(C'\fR constants).	1164	of the \f(CW\(C`SIGxxx\(C'\fR constants).
1159	.ie n .Sh """ev_child"" \- wait for pid status changes"	1165	.ie n .Sh """ev_child"" \- watch out for process status changes"
1160	.el .Sh "\f(CWev_child\fP \- wait for pid status changes"	1166	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1161	.IX Subsection "ev_child - wait for pid status changes"	1167	.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	1168	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).	1169	some child status changes (most typically when a child of yours dies).
1164	.IP "ev_child_init (ev_child *, callback, int pid)" 4	1170	.IP "ev_child_init (ev_child *, callback, int pid)" 4
1165	.IX Item "ev_child_init (ev_child *, callback, int pid)"	1171	.IX Item "ev_child_init (ev_child *, callback, int pid)"
1166	.PD 0	1172	.PD 0
…		…
1187	.Vb 3	1193	.Vb 3
1188	\& struct ev_signal signal_watcher;	1194	\& struct ev_signal signal_watcher;
1189	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1195	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1190	\& ev_signal_start (loop, &sigint_cb);	1196	\& ev_signal_start (loop, &sigint_cb);
1191	.Ve	1197	.Ve
1192	.ie n .Sh """ev_idle"" \- when you've got nothing better to do"	1198	.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"	1199	.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"	1200	.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	1201	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	1202	(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,	1203	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	1204	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 \-	1205	watchers are being called again and again, once per event loop iteration \-
…		…
1229	.Vb 3	1235	.Vb 3
1230	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1236	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1231	\& ev_idle_init (idle_watcher, idle_cb);	1237	\& ev_idle_init (idle_watcher, idle_cb);
1232	\& ev_idle_start (loop, idle_cb);	1238	\& ev_idle_start (loop, idle_cb);
1233	.Ve	1239	.Ve
1234	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop"	1240	.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"	1241	.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"	1242	.IX Subsection "ev_prepare and ev_check - customise your event loop!"
1237	Prepare and check watchers are usually (but not always) used in tandem:	1243	Prepare and check watchers are usually (but not always) used in tandem:
1238	prepare watchers get invoked before the process blocks and check watchers	1244	prepare watchers get invoked before the process blocks and check watchers
1239	afterwards.	1245	afterwards.
1240	.PP	1246	.PP
1241	Their main purpose is to integrate other event mechanisms into libev and	1247	Their main purpose is to integrate other event mechanisms into libev and
…		…
1269	Initialises and configures the prepare or check watcher \- they have no	1275	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	1276	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.	1277	macros, but using them is utterly, utterly and completely pointless.
1272	.PP	1278	.PP
1273	Example: TODO.	1279	Example: TODO.
1274	.ie n .Sh """ev_embed"" \- when one backend isn't enough"	1280	.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1275	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough"	1281	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1276	.IX Subsection "ev_embed - when one backend isn't enough"	1282	.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	1283	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	1284	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	1285	loop, other types of watchers might be handled in a delayed or incorrect
1280	fashion and must not be used).	1286	fashion and must not be used).
1281	.PP	1287	.PP
…		…
1432	.IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4	1438	.IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4
1433	.IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library."	1439	.IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library."
1434	.PD	1440	.PD
1435	.SH "\*(C+ SUPPORT"	1441	.SH "\*(C+ SUPPORT"
1436	.IX Header " SUPPORT"	1442	.IX Header " SUPPORT"
1437	\&\s-1TBD\s0.	1443	Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow
		1444	you to use some convinience methods to start/stop watchers and also change
		1445	the callback model to a model using method callbacks on objects.
		1446	.PP
		1447	To use it,
		1448	.PP
		1449	.Vb 1
		1450	\& #include <ev++.h>
		1451	.Ve
		1452	.PP
		1453	(it is not installed by default). This automatically includes \fIev.h\fR
		1454	and puts all of its definitions (many of them macros) into the global
		1455	namespace. All \(C+ specific things are put into the \f(CW\(C`ev\*(C'\fR namespace.
		1456	.PP
		1457	It should support all the same embedding options as \fIev.h\fR, most notably
		1458	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR.
		1459	.PP
		1460	Here is a list of things available in the \f(CW\(C`ev\(C'\fR namespace:
		1461	.ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4
		1462	.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4
		1463	.IX Item "ev::READ, ev::WRITE etc."
		1464	These are just enum values with the same values as the \f(CW\(C`EV_READ\(C'\fR etc.
		1465	macros from \fIev.h\fR.
		1466	.ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4
		1467	.el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4
		1468	.IX Item "ev::tstamp, ev::now"
		1469	Aliases to the same types/functions as with the \f(CW\(C`ev_\(C'\fR prefix.
		1470	.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
		1471	.el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4
		1472	.IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc."
		1473	For each \f(CW\(C`ev_TYPE\(C'\fR watcher in \fIev.h\fR there is a corresponding class of
		1474	the same name in the \f(CW\(C`ev\(C'\fR namespace, with the exception of \f(CW\(C`ev_signal\(C'\fR
		1475	which is called \f(CW\(C`ev::sig\(C'\fR to avoid clashes with the \f(CW\(C`signal\(C'\fR macro
		1476	defines by many implementations.
		1477	.Sp
		1478	All of those classes have these methods:
		1479	.RS 4
		1480	.IP "ev::TYPE::TYPE (object , object::method )" 4
		1481	.IX Item "ev::TYPE::TYPE (object , object::method )"
		1482	.PD 0
		1483	.IP "ev::TYPE::TYPE (object , object::method , struct ev_loop *)" 4
		1484	.IX Item "ev::TYPE::TYPE (object , object::method , struct ev_loop *)"
		1485	.IP "ev::TYPE::~TYPE" 4
		1486	.IX Item "ev::TYPE::~TYPE"
		1487	.PD
		1488	The constructor takes a pointer to an object and a method pointer to
		1489	the event handler callback to call in this class. The constructor calls
		1490	\&\f(CW\(C`ev_init\(C'\fR for you, which means you have to call the \f(CW\(C`set\(C'\fR method
		1491	before starting it. If you do not specify a loop then the constructor
		1492	automatically associates the default loop with this watcher.
		1493	.Sp
		1494	The destructor automatically stops the watcher if it is active.
		1495	.IP "w\->set (struct ev_loop *)" 4
		1496	.IX Item "w->set (struct ev_loop *)"
		1497	Associates a different \f(CW\(C`struct ev_loop\(C'\fR with this watcher. You can only
		1498	do this when the watcher is inactive (and not pending either).
		1499	.IP "w\->set ([args])" 4
		1500	.IX Item "w->set ([args])"
		1501	Basically the same as \f(CW\(C`ev_TYPE_set\(C'\fR, with the same args. Must be
		1502	called at least once. Unlike the C counterpart, an active watcher gets
		1503	automatically stopped and restarted.
		1504	.IP "w\->start ()" 4
		1505	.IX Item "w->start ()"
		1506	Starts the watcher. Note that there is no \f(CW\(C`loop\(C'\fR argument as the
		1507	constructor already takes the loop.
		1508	.IP "w\->stop ()" 4
		1509	.IX Item "w->stop ()"
		1510	Stops the watcher if it is active. Again, no \f(CW\(C`loop\(C'\fR argument.
		1511	.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4
		1512	.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4
		1513	.IX Item "w->again () ev::timer, ev::periodic only"
		1514	For \f(CW\(C`ev::timer\(C'\fR and \f(CW\(C`ev::periodic\(C'\fR, this invokes the corresponding
		1515	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.
		1516	.ie n .IP "w\->sweep () ""ev::embed"" only" 4
		1517	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
		1518	.IX Item "w->sweep () ev::embed only"
		1519	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.
		1520	.RE
		1521	.RS 4
		1522	.RE
		1523	.PP
		1524	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
		1525	the constructor.
		1526	.PP
		1527	.Vb 4
		1528	\& class myclass
		1529	\& {
		1530	\& ev_io io; void io_cb (ev::io &w, int revents);
		1531	\& ev_idle idle void idle_cb (ev::idle &w, int revents);
		1532	.Ve
		1533	.PP
		1534	.Vb 2
		1535	\& myclass ();
		1536	\& }
		1537	.Ve
		1538	.PP
		1539	.Vb 6
		1540	\& myclass::myclass (int fd)
		1541	\& : io (this, &myclass::io_cb),
		1542	\& idle (this, &myclass::idle_cb)
		1543	\& {
		1544	\& io.start (fd, ev::READ);
		1545	\& }
		1546	.Ve
		1547	.SH "EMBEDDING"
		1548	.IX Header "EMBEDDING"
		1549	Libev can (and often is) directly embedded into host
		1550	applications. Examples of applications that embed it include the Deliantra
		1551	Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe)
		1552	and rxvt\-unicode.
		1553	.PP
		1554	The goal is to enable you to just copy the neecssary files into your
		1555	source directory without having to change even a single line in them, so
		1556	you can easily upgrade by simply copying (or having a checked-out copy of
		1557	libev somewhere in your source tree).
		1558	.Sh "\s-1FILESETS\s0"
		1559	.IX Subsection "FILESETS"
		1560	Depending on what features you need you need to include one or more sets of files
		1561	in your app.
		1562	.PP
		1563	\fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR
		1564	.IX Subsection "CORE EVENT LOOP"
		1565	.PP
		1566	To include only the libev core (all the \f(CW\(C`ev_\*(C'\fR functions), with manual
		1567	configuration (no autoconf):
		1568	.PP
		1569	.Vb 2
		1570	\& #define EV_STANDALONE 1
		1571	\& #include "ev.c"
		1572	.Ve
		1573	.PP
		1574	This will automatically include \fIev.h\fR, too, and should be done in a
		1575	single C source file only to provide the function implementations. To use
		1576	it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best
		1577	done by writing a wrapper around \fIev.h\fR that you can include instead and
		1578	where you can put other configuration options):
		1579	.PP
		1580	.Vb 2
		1581	\& #define EV_STANDALONE 1
		1582	\& #include "ev.h"
		1583	.Ve
		1584	.PP
		1585	Both header files and implementation files can be compiled with a \*(C+
		1586	compiler (at least, thats a stated goal, and breakage will be treated
		1587	as a bug).
		1588	.PP
		1589	You need the following files in your source tree, or in a directory
		1590	in your include path (e.g. in libev/ when using \-Ilibev):
		1591	.PP
		1592	.Vb 4
		1593	\& ev.h
		1594	\& ev.c
		1595	\& ev_vars.h
		1596	\& ev_wrap.h
		1597	.Ve
		1598	.PP
		1599	.Vb 1
		1600	\& ev_win32.c required on win32 platforms only
		1601	.Ve
		1602	.PP
		1603	.Vb 5
		1604	\& ev_select.c only when select backend is enabled (which is is by default)
		1605	\& ev_poll.c only when poll backend is enabled (disabled by default)
		1606	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
		1607	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
		1608	\& ev_port.c only when the solaris port backend is enabled (disabled by default)
		1609	.Ve
		1610	.PP
		1611	\&\fIev.c\fR includes the backend files directly when enabled, so you only need
		1612	to compile a single file.
		1613	.PP
		1614	\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR
		1615	.IX Subsection "LIBEVENT COMPATIBILITY API"
		1616	.PP
		1617	To include the libevent compatibility \s-1API\s0, also include:
		1618	.PP
		1619	.Vb 1
		1620	\& #include "event.c"
		1621	.Ve
		1622	.PP
		1623	in the file including \fIev.c\fR, and:
		1624	.PP
		1625	.Vb 1
		1626	\& #include "event.h"
		1627	.Ve
		1628	.PP
		1629	in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR.
		1630	.PP
		1631	You need the following additional files for this:
		1632	.PP
		1633	.Vb 2
		1634	\& event.h
		1635	\& event.c
		1636	.Ve
		1637	.PP
		1638	\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR
		1639	.IX Subsection "AUTOCONF SUPPORT"
		1640	.PP
		1641	Instead of using \f(CW\(C`EV_STANDALONE=1\(C'\fR and providing your config in
		1642	whatever way you want, you can also \f(CW\(C`m4_include([libev.m4])\(C'\fR in your
		1643	\&\fIconfigure.ac\fR and leave \f(CW\(C`EV_STANDALONE\(C'\fR off. \fIev.c\fR will then include
		1644	\&\fIconfig.h\fR and configure itself accordingly.
		1645	.PP
		1646	For this of course you need the m4 file:
		1647	.PP
		1648	.Vb 1
		1649	\& libev.m4
		1650	.Ve
		1651	.Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0"
		1652	.IX Subsection "PREPROCESSOR SYMBOLS/MACROS"
		1653	Libev can be configured via a variety of preprocessor symbols you have to define
		1654	before including any of its files. The default is not to build for multiplicity
		1655	and only include the select backend.
		1656	.IP "\s-1EV_STANDALONE\s0" 4
		1657	.IX Item "EV_STANDALONE"
		1658	Must always be \f(CW1\fR if you do not use autoconf configuration, which
		1659	keeps libev from including \fIconfig.h\fR, and it also defines dummy
		1660	implementations for some libevent functions (such as logging, which is not
		1661	supported). It will also not define any of the structs usually found in
		1662	\&\fIevent.h\fR that are not directly supported by the libev core alone.
		1663	.IP "\s-1EV_USE_MONOTONIC\s0" 4
		1664	.IX Item "EV_USE_MONOTONIC"
		1665	If defined to be \f(CW1\fR, libev will try to detect the availability of the
		1666	monotonic clock option at both compiletime and runtime. Otherwise no use
		1667	of the monotonic clock option will be attempted. If you enable this, you
		1668	usually have to link against librt or something similar. Enabling it when
		1669	the functionality isn't available is safe, though, althoguh you have
		1670	to make sure you link against any libraries where the \f(CW\(C`clock_gettime\(C'\fR
		1671	function is hiding in (often \fI\-lrt\fR).
		1672	.IP "\s-1EV_USE_REALTIME\s0" 4
		1673	.IX Item "EV_USE_REALTIME"
		1674	If defined to be \f(CW1\fR, libev will try to detect the availability of the
		1675	realtime clock option at compiletime (and assume its availability at
		1676	runtime if successful). Otherwise no use of the realtime clock option will
		1677	be attempted. This effectively replaces \f(CW\(C`gettimeofday\(C'\fR by \f(CW\*(C`clock_get
		1678	(CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries
		1679	in the description of \f(CW\(C`EV_USE_MONOTONIC\(C'\fR, though.
		1680	.IP "\s-1EV_USE_SELECT\s0" 4
		1681	.IX Item "EV_USE_SELECT"
		1682	If undefined or defined to be \f(CW1\fR, libev will compile in support for the
		1683	\&\f(CW\(C`select\(C'\fR(2) backend. No attempt at autodetection will be done: if no
		1684	other method takes over, select will be it. Otherwise the select backend
		1685	will not be compiled in.
		1686	.IP "\s-1EV_SELECT_USE_FD_SET\s0" 4
		1687	.IX Item "EV_SELECT_USE_FD_SET"
		1688	If defined to \f(CW1\fR, then the select backend will use the system \f(CW\(C`fd_set\(C'\fR
		1689	structure. This is useful if libev doesn't compile due to a missing
		1690	\&\f(CW\(C`NFDBITS\(C'\fR or \f(CW\(C`fd_mask\(C'\fR definition or it misguesses the bitset layout on
		1691	exotic systems. This usually limits the range of file descriptors to some
		1692	low limit such as 1024 or might have other limitations (winsocket only
		1693	allows 64 sockets). The \f(CW\(C`FD_SETSIZE\(C'\fR macro, set before compilation, might
		1694	influence the size of the \f(CW\(C`fd_set\(C'\fR used.
		1695	.IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4
		1696	.IX Item "EV_SELECT_IS_WINSOCKET"
		1697	When defined to \f(CW1\fR, the select backend will assume that
		1698	select/socket/connect etc. don't understand file descriptors but
		1699	wants osf handles on win32 (this is the case when the select to
		1700	be used is the winsock select). This means that it will call
		1701	\&\f(CW\(C`_get_osfhandle\(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise,
		1702	it is assumed that all these functions actually work on fds, even
		1703	on win32. Should not be defined on non\-win32 platforms.
		1704	.IP "\s-1EV_USE_POLL\s0" 4
		1705	.IX Item "EV_USE_POLL"
		1706	If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\(C`poll\(C'\fR(2)
		1707	backend. Otherwise it will be enabled on non\-win32 platforms. It
		1708	takes precedence over select.
		1709	.IP "\s-1EV_USE_EPOLL\s0" 4
		1710	.IX Item "EV_USE_EPOLL"
		1711	If defined to be \f(CW1\fR, libev will compile in support for the Linux
		1712	\&\f(CW\(C`epoll\(C'\fR(7) backend. Its availability will be detected at runtime,
		1713	otherwise another method will be used as fallback. This is the
		1714	preferred backend for GNU/Linux systems.
		1715	.IP "\s-1EV_USE_KQUEUE\s0" 4
		1716	.IX Item "EV_USE_KQUEUE"
		1717	If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style
		1718	\&\f(CW\(C`kqueue\(C'\fR(2) backend. Its actual availability will be detected at runtime,
		1719	otherwise another method will be used as fallback. This is the preferred
		1720	backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only
		1721	supports some types of fds correctly (the only platform we found that
		1722	supports ptys for example was NetBSD), so kqueue might be compiled in, but
		1723	not be used unless explicitly requested. The best way to use it is to find
		1724	out whether kqueue supports your type of fd properly and use an embedded
		1725	kqueue loop.
		1726	.IP "\s-1EV_USE_PORT\s0" 4
		1727	.IX Item "EV_USE_PORT"
		1728	If defined to be \f(CW1\fR, libev will compile in support for the Solaris
		1729	10 port style backend. Its availability will be detected at runtime,
		1730	otherwise another method will be used as fallback. This is the preferred
		1731	backend for Solaris 10 systems.
		1732	.IP "\s-1EV_USE_DEVPOLL\s0" 4
		1733	.IX Item "EV_USE_DEVPOLL"
		1734	reserved for future expansion, works like the \s-1USE\s0 symbols above.
		1735	.IP "\s-1EV_H\s0" 4
		1736	.IX Item "EV_H"
		1737	The name of the \fIev.h\fR header file used to include it. The default if
		1738	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
		1739	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
		1740	.IP "\s-1EV_CONFIG_H\s0" 4
		1741	.IX Item "EV_CONFIG_H"
		1742	If \f(CW\(C`EV_STANDALONE\(C'\fR isn't \f(CW1\fR, this variable can be used to override
		1743	\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
		1744	\&\f(CW\(C`EV_H\(C'\fR, above.
		1745	.IP "\s-1EV_EVENT_H\s0" 4
		1746	.IX Item "EV_EVENT_H"
		1747	Similarly to \f(CW\(C`EV_H\(C'\fR, this macro can be used to override \fIevent.c\fR's idea
		1748	of how the \fIevent.h\fR header can be found.
		1749	.IP "\s-1EV_PROTOTYPES\s0" 4
		1750	.IX Item "EV_PROTOTYPES"
		1751	If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
		1752	prototypes, but still define all the structs and other symbols. This is
		1753	occasionally useful if you want to provide your own wrapper functions
		1754	around libev functions.
		1755	.IP "\s-1EV_MULTIPLICITY\s0" 4
		1756	.IX Item "EV_MULTIPLICITY"
		1757	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
		1758	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create
		1759	additional independent event loops. Otherwise there will be no support
		1760	for multiple event loops and there is no first event loop pointer
		1761	argument. Instead, all functions act on the single default loop.
		1762	.IP "\s-1EV_PERIODICS\s0" 4
		1763	.IX Item "EV_PERIODICS"
		1764	If undefined or defined to be \f(CW1\fR, then periodic timers are supported,
		1765	otherwise not. This saves a few kb of code.
		1766	.IP "\s-1EV_COMMON\s0" 4
		1767	.IX Item "EV_COMMON"
		1768	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining
		1769	this macro to a something else you can include more and other types of
		1770	members. You have to define it each time you include one of the files,
		1771	though, and it must be identical each time.
		1772	.Sp
		1773	For example, the perl \s-1EV\s0 module uses something like this:
		1774	.Sp
		1775	.Vb 3
		1776	\& #define EV_COMMON \e
		1777	\& SV self; / contains this struct */ \e
		1778	\& SV cb_sv, fh /* note no trailing ";" */
		1779	.Ve
		1780	.IP "\s-1EV_CB_DECLARE\s0(type)" 4
		1781	.IX Item "EV_CB_DECLARE(type)"
		1782	.PD 0
		1783	.IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4
		1784	.IX Item "EV_CB_INVOKE(watcher,revents)"
		1785	.IP "ev_set_cb(ev,cb)" 4
		1786	.IX Item "ev_set_cb(ev,cb)"
		1787	.PD
		1788	Can be used to change the callback member declaration in each watcher,
		1789	and the way callbacks are invoked and set. Must expand to a struct member
		1790	definition and a statement, respectively. See the \fIev.v\fR header file for
		1791	their default definitions. One possible use for overriding these is to
		1792	avoid the ev_loop pointer as first argument in all cases, or to use method
		1793	calls instead of plain function calls in \*(C+.
		1794	.Sh "\s-1EXAMPLES\s0"
		1795	.IX Subsection "EXAMPLES"
		1796	For a real-world example of a program the includes libev
		1797	verbatim, you can have a look at the \s-1EV\s0 perl module
		1798	(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
		1799	the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public
		1800	interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
		1801	will be compiled. It is pretty complex because it provides its own header
		1802	file.
		1803	.Sp
		1804	The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
		1805	that everybody includes and which overrides some autoconf choices:
		1806	.Sp
		1807	.Vb 4
		1808	\& #define EV_USE_POLL 0
		1809	\& #define EV_MULTIPLICITY 0
		1810	\& #define EV_PERIODICS 0
		1811	\& #define EV_CONFIG_H <config.h>
		1812	.Ve
		1813	.Sp
		1814	.Vb 1
		1815	\& #include "ev++.h"
		1816	.Ve
		1817	.Sp
		1818	And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled:
		1819	.Sp
		1820	.Vb 2
		1821	\& #include "ev_cpp.h"
		1822	\& #include "ev.c"
		1823	.Ve
1438	.SH "AUTHOR"	1824	.SH "AUTHOR"
1439	.IX Header "AUTHOR"	1825	.IX Header "AUTHOR"
1440	Marc Lehmann <libev@schmorp.de>.	1826	Marc Lehmann <libev@schmorp.de>.

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Comparing libev/ev.3 (file contents):
Revision 1.12 by root, Sat Nov 24 07:20:42 2007 UTC vs.
Revision 1.17 by root, Sat Nov 24 16:31:45 2007 UTC