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

Comparing libev/ev.3 (file contents):
Revision 1.10 by root, Sat Nov 24 06:23:27 2007 UTC vs.
Revision 1.23 by root, Tue Nov 27 08:20:42 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
…		…
458	\& fatal ("no epoll found here, maybe it hides under your chair");	458	\& fatal ("no epoll found here, maybe it hides under your chair");
459	.Ve	459	.Ve
460	.IP "ev_default_destroy ()" 4	460	.IP "ev_default_destroy ()" 4
461	.IX Item "ev_default_destroy ()"	461	.IX Item "ev_default_destroy ()"
462	Destroys the default loop again (frees all memory and kernel state	462	Destroys the default loop again (frees all memory and kernel state
463	etc.). This stops all registered event watchers (by not touching them in	463	etc.). None of the active event watchers will be stopped in the normal
464	any way whatsoever, although you cannot rely on this :).	464	sense, so e.g. \f(CW\(C`ev_is_active\(C'\fR might still return true. It is your
		465	responsibility to either stop all watchers cleanly yoursef \fIbefore\fR
		466	calling this function, or cope with the fact afterwards (which is usually
		467	the easiest thing, youc na just ignore the watchers and/or \f(CW\(C`free ()\(C'\fR them
		468	for example).
465	.IP "ev_loop_destroy (loop)" 4	469	.IP "ev_loop_destroy (loop)" 4
466	.IX Item "ev_loop_destroy (loop)"	470	.IX Item "ev_loop_destroy (loop)"
467	Like \f(CW\(C`ev_default_destroy\(C'\fR, but destroys an event loop created by an	471	Like \f(CW\(C`ev_default_destroy\(C'\fR, but destroys an event loop created by an
468	earlier call to \f(CW\(C`ev_loop_new\(C'\fR.	472	earlier call to \f(CW\(C`ev_loop_new\(C'\fR.
469	.IP "ev_default_fork ()" 4	473	.IP "ev_default_fork ()" 4
…		…
645	)\(C'\fR), and you can stop watching for events at any time by calling the	649	)\(C'\fR), and you can stop watching for events at any time by calling the
646	corresponding stop function (\f(CW\(C`ev_<type>_stop (loop, watcher )\*(C'\fR.	650	corresponding stop function (\f(CW\(C`ev_<type>_stop (loop, watcher )\*(C'\fR.
647	.PP	651	.PP
648	As long as your watcher is active (has been started but not stopped) you	652	As long as your watcher is active (has been started but not stopped) you
649	must not touch the values stored in it. Most specifically you must never	653	must not touch the values stored in it. Most specifically you must never
650	reinitialise it or call its set macro.	654	reinitialise it or call its \f(CW\(C`set\(C'\fR macro.
651	.PP
652	You can check whether an event is active by calling the \f(CW\*(C`ev_is_active
653	(watcher )\(C'\fR macro. To see whether an event is outstanding (but the
654	callback for it has not been called yet) you can use the \f(CW\*(C`ev_is_pending
655	(watcher )\(C'\fR macro.
656	.PP	655	.PP
657	Each and every callback receives the event loop pointer as first, the	656	Each and every callback receives the event loop pointer as first, the
658	registered watcher structure as second, and a bitset of received events as	657	registered watcher structure as second, and a bitset of received events as
659	third argument.	658	third argument.
660	.PP	659	.PP
…		…
685	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.
686	.ie n .IP """EV_CHILD""" 4	685	.ie n .IP """EV_CHILD""" 4
687	.el .IP "\f(CWEV_CHILD\fR" 4	686	.el .IP "\f(CWEV_CHILD\fR" 4
688	.IX Item "EV_CHILD"	687	.IX Item "EV_CHILD"
689	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.
690	.ie n .IP """EV_IDLE""" 4	693	.ie n .IP """EV_IDLE""" 4
691	.el .IP "\f(CWEV_IDLE\fR" 4	694	.el .IP "\f(CWEV_IDLE\fR" 4
692	.IX Item "EV_IDLE"	695	.IX Item "EV_IDLE"
693	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.
694	.ie n .IP """EV_PREPARE""" 4	697	.ie n .IP """EV_PREPARE""" 4
…		…
718	Libev will usually signal a few \(L"dummy\(R" events together with an error,	721	Libev will usually signal a few \(L"dummy\(R" events together with an error,
719	for example it might indicate that a fd is readable or writable, and if	722	for example it might indicate that a fd is readable or writable, and if
720	your callbacks is well-written it can just attempt the operation and cope	723	your callbacks is well-written it can just attempt the operation and cope
721	with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded	724	with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded
722	programs, though, so beware.	725	programs, though, so beware.
		726	.Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"
		727	.IX Subsection "GENERIC WATCHER FUNCTIONS"
		728	In the following description, \f(CW\(C`TYPE\(C'\fR stands for the watcher type,
		729	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.
		730	.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
		731	.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4
		732	.IX Item "ev_init (ev_TYPE *watcher, callback)"
		733	This macro initialises the generic portion of a watcher. The contents
		734	of the watcher object can be arbitrary (so \f(CW\(C`malloc\(C'\fR will do). Only
		735	the generic parts of the watcher are initialised, you \fIneed\fR to call
		736	the type-specific \f(CW\(C`ev_TYPE_set\(C'\fR macro afterwards to initialise the
		737	type-specific parts. For each type there is also a \f(CW\(C`ev_TYPE_init\(C'\fR macro
		738	which rolls both calls into one.
		739	.Sp
		740	You can reinitialise a watcher at any time as long as it has been stopped
		741	(or never started) and there are no pending events outstanding.
		742	.Sp
		743	The callback is always of type \f(CW\(C`void ()(ev_loop loop, ev_TYPE watcher,
		744	int revents)\*(C'\fR.
		745	.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4
		746	.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4
		747	.IX Item "ev_TYPE_set (ev_TYPE *, [args])"
		748	This macro initialises the type-specific parts of a watcher. You need to
		749	call \f(CW\(C`ev_init\(C'\fR at least once before you call this macro, but you can
		750	call \f(CW\(C`ev_TYPE_set\(C'\fR any number of times. You must not, however, call this
		751	macro on a watcher that is active (it can be pending, however, which is a
		752	difference to the \f(CW\(C`ev_init\(C'\fR macro).
		753	.Sp
		754	Although some watcher types do not have type-specific arguments
		755	(e.g. \f(CW\(C`ev_prepare\(C'\fR) you still need to call its \f(CW\(C`set\(C'\fR macro.
		756	.ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4
		757	.el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4
		758	.IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])"
		759	This convinience macro rolls both \f(CW\(C`ev_init\(C'\fR and \f(CW\(C`ev_TYPE_set\(C'\fR macro
		760	calls into a single call. This is the most convinient method to initialise
		761	a watcher. The same limitations apply, of course.
		762	.ie n .IP """ev_TYPE_start"" (loop , ev_TYPE watcher)" 4
		763	.el .IP "\f(CWev_TYPE_start\fR (loop , ev_TYPE watcher)" 4
		764	.IX Item "ev_TYPE_start (loop , ev_TYPE watcher)"
		765	Starts (activates) the given watcher. Only active watchers will receive
		766	events. If the watcher is already active nothing will happen.
		767	.ie n .IP """ev_TYPE_stop"" (loop , ev_TYPE watcher)" 4
		768	.el .IP "\f(CWev_TYPE_stop\fR (loop , ev_TYPE watcher)" 4
		769	.IX Item "ev_TYPE_stop (loop , ev_TYPE watcher)"
		770	Stops the given watcher again (if active) and clears the pending
		771	status. It is possible that stopped watchers are pending (for example,
		772	non-repeating timers are being stopped when they become pending), but
		773	\&\f(CW\(C`ev_TYPE_stop\(C'\fR ensures that the watcher is neither active nor pending. If
		774	you want to free or reuse the memory used by the watcher it is therefore a
		775	good idea to always call its \f(CW\(C`ev_TYPE_stop\(C'\fR function.
		776	.IP "bool ev_is_active (ev_TYPE *watcher)" 4
		777	.IX Item "bool ev_is_active (ev_TYPE *watcher)"
		778	Returns a true value iff the watcher is active (i.e. it has been started
		779	and not yet been stopped). As long as a watcher is active you must not modify
		780	it.
		781	.IP "bool ev_is_pending (ev_TYPE *watcher)" 4
		782	.IX Item "bool ev_is_pending (ev_TYPE *watcher)"
		783	Returns a true value iff the watcher is pending, (i.e. it has outstanding
		784	events but its callback has not yet been invoked). As long as a watcher
		785	is pending (but not active) you must not call an init function on it (but
		786	\&\f(CW\(C`ev_TYPE_set\(C'\fR is safe) and you must make sure the watcher is available to
		787	libev (e.g. you cnanot \f(CW\(C`free ()\(C'\fR it).
		788	.IP "callback = ev_cb (ev_TYPE *watcher)" 4
		789	.IX Item "callback = ev_cb (ev_TYPE *watcher)"
		790	Returns the callback currently set on the watcher.
		791	.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
		792	.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
		793	Change the callback. You can change the callback at virtually any time
		794	(modulo threads).
723	.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"	795	.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"
724	.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"	796	.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
725	Each watcher has, by default, a member \f(CW\(C`void data\*(C'\fR that you can change	797	Each watcher has, by default, a member \f(CW\(C`void data\*(C'\fR that you can change
726	and read at any time, libev will completely ignore it. This can be used	798	and read at any time, libev will completely ignore it. This can be used
727	to associate arbitrary data with your watcher. If you need more data and	799	to associate arbitrary data with your watcher. If you need more data and
…		…
753	More interesting and less C\-conformant ways of catsing your callback type	825	More interesting and less C\-conformant ways of catsing your callback type
754	have been omitted....	826	have been omitted....
755	.SH "WATCHER TYPES"	827	.SH "WATCHER TYPES"
756	.IX Header "WATCHER TYPES"	828	.IX Header "WATCHER TYPES"
757	This section describes each watcher in detail, but will not repeat	829	This section describes each watcher in detail, but will not repeat
758	information given in the last section.	830	information given in the last section. Any initialisation/set macros,
		831	functions and members specific to the watcher type are explained.
		832	.PP
		833	Members are additionally marked with either \fI[read\-only]\fR, meaning that,
		834	while the watcher is active, you can look at the member and expect some
		835	sensible content, but you must not modify it (you can modify it while the
		836	watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
		837	means you can expect it to have some sensible content while the watcher
		838	is active, but you can also modify it. Modifying it may not do something
		839	sensible or take immediate effect (or do anything at all), but libev will
		840	not crash or malfunction in any way.
759	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable"	841	.ie n .Sh """ev_io"" \- is this file descriptor readable or writable?"
760	.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable"	842	.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?"
761	.IX Subsection "ev_io - is this file descriptor readable or writable"	843	.IX Subsection "ev_io - is this file descriptor readable or writable?"
762	I/O watchers check whether a file descriptor is readable or writable	844	I/O watchers check whether a file descriptor is readable or writable
763	in each iteration of the event loop (This behaviour is called	845	in each iteration of the event loop, or, more precisely, when reading
764	level-triggering because you keep receiving events as long as the	846	would not block the process and writing would at least be able to write
765	condition persists. Remember you can stop the watcher if you don't want to	847	some data. This behaviour is called level-triggering because you keep
766	act on the event and neither want to receive future events).	848	receiving events as long as the condition persists. Remember you can stop
		849	the watcher if you don't want to act on the event and neither want to
		850	receive future events.
767	.PP	851	.PP
768	In general you can register as many read and/or write event watchers per	852	In general you can register as many read and/or write event watchers per
769	fd as you want (as long as you don't confuse yourself). Setting all file	853	fd as you want (as long as you don't confuse yourself). Setting all file
770	descriptors to non-blocking mode is also usually a good idea (but not	854	descriptors to non-blocking mode is also usually a good idea (but not
771	required if you know what you are doing).	855	required if you know what you are doing).
772	.PP	856	.PP
773	You have to be careful with dup'ed file descriptors, though. Some backends	857	You have to be careful with dup'ed file descriptors, though. Some backends
774	(the linux epoll backend is a notable example) cannot handle dup'ed file	858	(the linux epoll backend is a notable example) cannot handle dup'ed file
775	descriptors correctly if you register interest in two or more fds pointing	859	descriptors correctly if you register interest in two or more fds pointing
776	to the same underlying file/socket etc. description (that is, they share	860	to the same underlying file/socket/etc. description (that is, they share
777	the same underlying \(L"file open\(R").	861	the same underlying \(L"file open\(R").
778	.PP	862	.PP
779	If you must do this, then force the use of a known-to-be-good backend	863	If you must do this, then force the use of a known-to-be-good backend
780	(at the time of this writing, this includes only \f(CW\(C`EVBACKEND_SELECT\(C'\fR and	864	(at the time of this writing, this includes only \f(CW\(C`EVBACKEND_SELECT\(C'\fR and
781	\&\f(CW\(C`EVBACKEND_POLL\(C'\fR).	865	\&\f(CW\(C`EVBACKEND_POLL\(C'\fR).
		866	.PP
		867	Another thing you have to watch out for is that it is quite easy to
		868	receive \(L"spurious\(R" readyness notifications, that is your callback might
		869	be called with \f(CW\(C`EV_READ\(C'\fR but a subsequent \f(CW\(C`read\(C'\fR(2) will actually block
		870	because there is no data. Not only are some backends known to create a
		871	lot of those (for example solaris ports), it is very easy to get into
		872	this situation even with a relatively standard program structure. Thus
		873	it is best to always use non-blocking I/O: An extra \f(CW\(C`read\(C'\fR(2) returning
		874	\&\f(CW\(C`EAGAIN\(C'\fR is far preferable to a program hanging until some data arrives.
		875	.PP
		876	If you cannot run the fd in non-blocking mode (for example you should not
		877	play around with an Xlib connection), then you have to seperately re-test
		878	wether a file descriptor is really ready with a known-to-be good interface
		879	such as poll (fortunately in our Xlib example, Xlib already does this on
		880	its own, so its quite safe to use).
782	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4	881	.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
783	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"	882	.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
784	.PD 0	883	.PD 0
785	.IP "ev_io_set (ev_io *, int fd, int events)" 4	884	.IP "ev_io_set (ev_io *, int fd, int events)" 4
786	.IX Item "ev_io_set (ev_io *, int fd, int events)"	885	.IX Item "ev_io_set (ev_io *, int fd, int events)"
787	.PD	886	.PD
788	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The fd is the file descriptor to rceeive	887	Configures an \f(CW\(C`ev_io\(C'\fR watcher. The \f(CW\(C`fd\(C'\fR is the file descriptor to
789	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 \|	888	rceeive events for and events is either \f(CW\(C`EV_READ\(C'\fR, \f(CW\(C`EV_WRITE\(C'\fR or
790	EV_WRITE\*(C'\fR to receive the given events.	889	\&\f(CW\(C`EV_READ \| EV_WRITE\(C'\fR to receive the given events.
791	.Sp	890	.IP "int fd [read\-only]" 4
792	Please note that most of the more scalable backend mechanisms (for example	891	.IX Item "int fd [read-only]"
793	epoll and solaris ports) can result in spurious readyness notifications	892	The file descriptor being watched.
794	for file descriptors, so you practically need to use non-blocking I/O (and	893	.IP "int events [read\-only]" 4
795	treat callback invocation as hint only), or retest separately with a safe	894	.IX Item "int events [read-only]"
796	interface before doing I/O (XLib can do this), or force the use of either	895	The events being watched.
797	\&\f(CW\(C`EVBACKEND_SELECT\(C'\fR or \f(CW\(C`EVBACKEND_POLL\(C'\fR, which don't suffer from this
798	problem. Also note that it is quite easy to have your callback invoked
799	when the readyness condition is no longer valid even when employing
800	typical ways of handling events, so its a good idea to use non-blocking
801	I/O unconditionally.
802	.PP	896	.PP
803	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well	897	Example: call \f(CW\(C`stdin_readable_cb\(C'\fR when \s-1STDIN_FILENO\s0 has become, well
804	readable, but only once. Since it is likely line\-buffered, you could	898	readable, but only once. Since it is likely line\-buffered, you could
805	attempt to read a whole line in the callback:	899	attempt to read a whole line in the callback:
806	.PP	900	.PP
…		…
819	\& struct ev_io stdin_readable;	913	\& struct ev_io stdin_readable;
820	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	914	\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
821	\& ev_io_start (loop, &stdin_readable);	915	\& ev_io_start (loop, &stdin_readable);
822	\& ev_loop (loop, 0);	916	\& ev_loop (loop, 0);
823	.Ve	917	.Ve
824	.ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts"	918	.ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts"
825	.el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts"	919	.el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts"
826	.IX Subsection "ev_timer - relative and optionally recurring timeouts"	920	.IX Subsection "ev_timer - relative and optionally repeating timeouts"
827	Timer watchers are simple relative timers that generate an event after a	921	Timer watchers are simple relative timers that generate an event after a
828	given time, and optionally repeating in regular intervals after that.	922	given time, and optionally repeating in regular intervals after that.
829	.PP	923	.PP
830	The timers are based on real time, that is, if you register an event that	924	The timers are based on real time, that is, if you register an event that
831	times out after an hour and you reset your system clock to last years	925	times out after an hour and you reset your system clock to last years
…		…
871	.Sp	965	.Sp
872	If the timer is repeating, either start it if necessary (with the repeat	966	If the timer is repeating, either start it if necessary (with the repeat
873	value), or reset the running timer to the repeat value.	967	value), or reset the running timer to the repeat value.
874	.Sp	968	.Sp
875	This sounds a bit complicated, but here is a useful and typical	969	This sounds a bit complicated, but here is a useful and typical
876	example: Imagine you have a tcp connection and you want a so-called idle	970	example: Imagine you have a tcp connection and you want a so-called
877	timeout, that is, you want to be called when there have been, say, 60	971	idle timeout, that is, you want to be called when there have been,
878	seconds of inactivity on the socket. The easiest way to do this is to	972	say, 60 seconds of inactivity on the socket. The easiest way to do
879	configure an \f(CW\(C`ev_timer\(C'\fR with after=repeat=60 and calling ev_timer_again each	973	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
880	time you successfully read or write some data. If you go into an idle	974	\&\f(CW\(C`ev_timer_again\(C'\fR each time you successfully read or write some data. If
881	state where you do not expect data to travel on the socket, you can stop	975	you go into an idle state where you do not expect data to travel on the
882	the timer, and again will automatically restart it if need be.	976	socket, you can stop the timer, and again will automatically restart it if
		977	need be.
		978	.Sp
		979	You can also ignore the \f(CW\(C`after\(C'\fR value and \f(CW\(C`ev_timer_start\(C'\fR altogether
		980	and only ever use the \f(CW\(C`repeat\(C'\fR value:
		981	.Sp
		982	.Vb 8
		983	\& ev_timer_init (timer, callback, 0., 5.);
		984	\& ev_timer_again (loop, timer);
		985	\& ...
		986	\& timer->again = 17.;
		987	\& ev_timer_again (loop, timer);
		988	\& ...
		989	\& timer->again = 10.;
		990	\& ev_timer_again (loop, timer);
		991	.Ve
		992	.Sp
		993	This is more efficient then stopping/starting the timer eahc time you want
		994	to modify its timeout value.
		995	.IP "ev_tstamp repeat [read\-write]" 4
		996	.IX Item "ev_tstamp repeat [read-write]"
		997	The current \f(CW\(C`repeat\(C'\fR value. Will be used each time the watcher times out
		998	or \f(CW\(C`ev_timer_again\(C'\fR is called and determines the next timeout (if any),
		999	which is also when any modifications are taken into account.
883	.PP	1000	.PP
884	Example: create a timer that fires after 60 seconds.	1001	Example: create a timer that fires after 60 seconds.
885	.PP	1002	.PP
886	.Vb 5	1003	.Vb 5
887	\& static void	1004	\& static void
…		…
918	.Vb 3	1035	.Vb 3
919	\& // and in some piece of code that gets executed on any "activity":	1036	\& // and in some piece of code that gets executed on any "activity":
920	\& // reset the timeout to start ticking again at 10 seconds	1037	\& // reset the timeout to start ticking again at 10 seconds
921	\& ev_timer_again (&mytimer);	1038	\& ev_timer_again (&mytimer);
922	.Ve	1039	.Ve
923	.ie n .Sh """ev_periodic"" \- to cron or not to cron"	1040	.ie n .Sh """ev_periodic"" \- to cron or not to cron?"
924	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron"	1041	.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?"
925	.IX Subsection "ev_periodic - to cron or not to cron"	1042	.IX Subsection "ev_periodic - to cron or not to cron?"
926	Periodic watchers are also timers of a kind, but they are very versatile	1043	Periodic watchers are also timers of a kind, but they are very versatile
927	(and unfortunately a bit complex).	1044	(and unfortunately a bit complex).
928	.PP	1045	.PP
929	Unlike \f(CW\(C`ev_timer\(C'\fR's, they are not based on real time (or relative time)	1046	Unlike \f(CW\(C`ev_timer\(C'\fR's, they are not based on real time (or relative time)
930	but on wallclock time (absolute time). You can tell a periodic watcher	1047	but on wallclock time (absolute time). You can tell a periodic watcher
931	to trigger \(L"at\(R" some specific point in time. For example, if you tell a	1048	to trigger \(L"at\(R" some specific point in time. For example, if you tell a
932	periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now ()	1049	periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now ()
933	+ 10.>) and then reset your system clock to the last year, then it will	1050	+ 10.\*(C'\fR) and then reset your system clock to the last year, then it will
934	take a year to trigger the event (unlike an \f(CW\(C`ev_timer\(C'\fR, which would trigger	1051	take a year to trigger the event (unlike an \f(CW\(C`ev_timer\(C'\fR, which would trigger
935	roughly 10 seconds later and of course not if you reset your system time	1052	roughly 10 seconds later and of course not if you reset your system time
936	again).	1053	again).
937	.PP	1054	.PP
938	They can also be used to implement vastly more complex timers, such as	1055	They can also be used to implement vastly more complex timers, such as
…		…
1019	.IX Item "ev_periodic_again (loop, ev_periodic *)"	1136	.IX Item "ev_periodic_again (loop, ev_periodic *)"
1020	Simply stops and restarts the periodic watcher again. This is only useful	1137	Simply stops and restarts the periodic watcher again. This is only useful
1021	when you changed some parameters or the reschedule callback would return	1138	when you changed some parameters or the reschedule callback would return
1022	a different time than the last time it was called (e.g. in a crond like	1139	a different time than the last time it was called (e.g. in a crond like
1023	program when the crontabs have changed).	1140	program when the crontabs have changed).
		1141	.IP "ev_tstamp interval [read\-write]" 4
		1142	.IX Item "ev_tstamp interval [read-write]"
		1143	The current interval value. Can be modified any time, but changes only
		1144	take effect when the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being
		1145	called.
		1146	.IP "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read\-write]" 4
		1147	.IX Item "ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]"
		1148	The current reschedule callback, or \f(CW0\fR, if this functionality is
		1149	switched off. Can be changed any time, but changes only take effect when
		1150	the periodic timer fires or \f(CW\(C`ev_periodic_again\(C'\fR is being called.
1024	.PP	1151	.PP
1025	Example: call a callback every hour, or, more precisely, whenever the	1152	Example: call a callback every hour, or, more precisely, whenever the
1026	system clock is divisible by 3600. The callback invocation times have	1153	system clock is divisible by 3600. The callback invocation times have
1027	potentially a lot of jittering, but good long-term stability.	1154	potentially a lot of jittering, but good long-term stability.
1028	.PP	1155	.PP
…		…
1064	\& struct ev_periodic hourly_tick;	1191	\& struct ev_periodic hourly_tick;
1065	\& ev_periodic_init (&hourly_tick, clock_cb,	1192	\& ev_periodic_init (&hourly_tick, clock_cb,
1066	\& fmod (ev_now (loop), 3600.), 3600., 0);	1193	\& fmod (ev_now (loop), 3600.), 3600., 0);
1067	\& ev_periodic_start (loop, &hourly_tick);	1194	\& ev_periodic_start (loop, &hourly_tick);
1068	.Ve	1195	.Ve
1069	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled"	1196	.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!"
1070	.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled"	1197	.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!"
1071	.IX Subsection "ev_signal - signal me when a signal gets signalled"	1198	.IX Subsection "ev_signal - signal me when a signal gets signalled!"
1072	Signal watchers will trigger an event when the process receives a specific	1199	Signal watchers will trigger an event when the process receives a specific
1073	signal one or more times. Even though signals are very asynchronous, libev	1200	signal one or more times. Even though signals are very asynchronous, libev
1074	will try it's best to deliver signals synchronously, i.e. as part of the	1201	will try it's best to deliver signals synchronously, i.e. as part of the
1075	normal event processing, like any other event.	1202	normal event processing, like any other event.
1076	.PP	1203	.PP
…		…
1086	.IP "ev_signal_set (ev_signal *, int signum)" 4	1213	.IP "ev_signal_set (ev_signal *, int signum)" 4
1087	.IX Item "ev_signal_set (ev_signal *, int signum)"	1214	.IX Item "ev_signal_set (ev_signal *, int signum)"
1088	.PD	1215	.PD
1089	Configures the watcher to trigger on the given signal number (usually one	1216	Configures the watcher to trigger on the given signal number (usually one
1090	of the \f(CW\(C`SIGxxx\(C'\fR constants).	1217	of the \f(CW\(C`SIGxxx\(C'\fR constants).
		1218	.IP "int signum [read\-only]" 4
		1219	.IX Item "int signum [read-only]"
		1220	The signal the watcher watches out for.
1091	.ie n .Sh """ev_child"" \- wait for pid status changes"	1221	.ie n .Sh """ev_child"" \- watch out for process status changes"
1092	.el .Sh "\f(CWev_child\fP \- wait for pid status changes"	1222	.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1093	.IX Subsection "ev_child - wait for pid status changes"	1223	.IX Subsection "ev_child - watch out for process status changes"
1094	Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to	1224	Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
1095	some child status changes (most typically when a child of yours dies).	1225	some child status changes (most typically when a child of yours dies).
1096	.IP "ev_child_init (ev_child *, callback, int pid)" 4	1226	.IP "ev_child_init (ev_child *, callback, int pid)" 4
1097	.IX Item "ev_child_init (ev_child *, callback, int pid)"	1227	.IX Item "ev_child_init (ev_child *, callback, int pid)"
1098	.PD 0	1228	.PD 0
…		…
1103	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look	1233	\&\fIany\fR process if \f(CW\(C`pid\(C'\fR is specified as \f(CW0\fR). The callback can look
1104	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see	1234	at the \f(CW\(C`rstatus\(C'\fR member of the \f(CW\(C`ev_child\(C'\fR watcher structure to see
1105	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems	1235	the status word (use the macros from \f(CW\(C`sys/wait.h\(C'\fR and see your systems
1106	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the	1236	\&\f(CW\(C`waitpid\(C'\fR documentation). The \f(CW\(C`rpid\(C'\fR member contains the pid of the
1107	process causing the status change.	1237	process causing the status change.
		1238	.IP "int pid [read\-only]" 4
		1239	.IX Item "int pid [read-only]"
		1240	The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
		1241	.IP "int rpid [read\-write]" 4
		1242	.IX Item "int rpid [read-write]"
		1243	The process id that detected a status change.
		1244	.IP "int rstatus [read\-write]" 4
		1245	.IX Item "int rstatus [read-write]"
		1246	The process exit/trace status caused by \f(CW\(C`rpid\(C'\fR (see your systems
		1247	\&\f(CW\(C`waitpid\(C'\fR and \f(CW\(C`sys/wait.h\(C'\fR documentation for details).
1108	.PP	1248	.PP
1109	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.	1249	Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1110	.PP	1250	.PP
1111	.Vb 5	1251	.Vb 5
1112	\& static void	1252	\& static void
…		…
1119	.Vb 3	1259	.Vb 3
1120	\& struct ev_signal signal_watcher;	1260	\& struct ev_signal signal_watcher;
1121	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1261	\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1122	\& ev_signal_start (loop, &sigint_cb);	1262	\& ev_signal_start (loop, &sigint_cb);
1123	.Ve	1263	.Ve
		1264	.ie n .Sh """ev_stat"" \- did the file attributes just change?"
		1265	.el .Sh "\f(CWev_stat\fP \- did the file attributes just change?"
		1266	.IX Subsection "ev_stat - did the file attributes just change?"
		1267	This watches a filesystem path for attribute changes. That is, it calls
		1268	\&\f(CW\(C`stat\(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed
		1269	compared to the last time, invoking the callback if it did.
		1270	.PP
		1271	The path does not need to exist: changing from \(L"path exists\(R" to \*(L"path does
		1272	not exist\(R" is a status change like any other. The condition \(L"path does
		1273	not exist\(R" is signified by the \f(CW\(C`st_nlink\*(C'\fR field being zero (which is
		1274	otherwise always forced to be at least one) and all the other fields of
		1275	the stat buffer having unspecified contents.
		1276	.PP
		1277	Since there is no standard to do this, the portable implementation simply
		1278	calls \f(CW\(C`stat (2)\(C'\fR regulalry on the path to see if it changed somehow. You
		1279	can specify a recommended polling interval for this case. If you specify
		1280	a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
		1281	unspecified default\fR value will be used (which you can expect to be around
		1282	five seconds, although this might change dynamically). Libev will also
		1283	impose a minimum interval which is currently around \f(CW0.1\fR, but thats
		1284	usually overkill.
		1285	.PP
		1286	This watcher type is not meant for massive numbers of stat watchers,
		1287	as even with OS-supported change notifications, this can be
		1288	resource\-intensive.
		1289	.PP
		1290	At the time of this writing, no specific \s-1OS\s0 backends are implemented, but
		1291	if demand increases, at least a kqueue and inotify backend will be added.
		1292	.IP "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)" 4
		1293	.IX Item "ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)"
		1294	.PD 0
		1295	.IP "ev_stat_set (ev_stat , const char path, ev_tstamp interval)" 4
		1296	.IX Item "ev_stat_set (ev_stat , const char path, ev_tstamp interval)"
		1297	.PD
		1298	Configures the watcher to wait for status changes of the given
		1299	\&\f(CW\(C`path\(C'\fR. The \f(CW\(C`interval\(C'\fR is a hint on how quickly a change is expected to
		1300	be detected and should normally be specified as \f(CW0\fR to let libev choose
		1301	a suitable value. The memory pointed to by \f(CW\(C`path\(C'\fR must point to the same
		1302	path for as long as the watcher is active.
		1303	.Sp
		1304	The callback will be receive \f(CW\(C`EV_STAT\(C'\fR when a change was detected,
		1305	relative to the attributes at the time the watcher was started (or the
		1306	last change was detected).
		1307	.IP "ev_stat_stat (ev_stat *)" 4
		1308	.IX Item "ev_stat_stat (ev_stat *)"
		1309	Updates the stat buffer immediately with new values. If you change the
		1310	watched path in your callback, you could call this fucntion to avoid
		1311	detecting this change (while introducing a race condition). Can also be
		1312	useful simply to find out the new values.
		1313	.IP "ev_statdata attr [read\-only]" 4
		1314	.IX Item "ev_statdata attr [read-only]"
		1315	The most-recently detected attributes of the file. Although the type is of
		1316	\&\f(CW\(C`ev_statdata\(C'\fR, this is usually the (or one of the) \f(CW\(C`struct stat\(C'\fR types
		1317	suitable for your system. If the \f(CW\(C`st_nlink\(C'\fR member is \f(CW0\fR, then there
		1318	was some error while \f(CW\(C`stat\(C'\fRing the file.
		1319	.IP "ev_statdata prev [read\-only]" 4
		1320	.IX Item "ev_statdata prev [read-only]"
		1321	The previous attributes of the file. The callback gets invoked whenever
		1322	\&\f(CW\(C`prev\(C'\fR != \f(CW\(C`attr\(C'\fR.
		1323	.IP "ev_tstamp interval [read\-only]" 4
		1324	.IX Item "ev_tstamp interval [read-only]"
		1325	The specified interval.
		1326	.IP "const char *path [read\-only]" 4
		1327	.IX Item "const char *path [read-only]"
		1328	The filesystem path that is being watched.
		1329	.PP
		1330	Example: Watch \f(CW\(C`/etc/passwd\(C'\fR for attribute changes.
		1331	.PP
		1332	.Vb 15
		1333	\& static void
		1334	\& passwd_cb (struct ev_loop loop, ev_stat w, int revents)
		1335	\& {
		1336	\& /* /etc/passwd changed in some way */
		1337	\& if (w->attr.st_nlink)
		1338	\& {
		1339	\& printf ("passwd current size %ld\en", (long)w->attr.st_size);
		1340	\& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime);
		1341	\& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime);
		1342	\& }
		1343	\& else
		1344	\& /* you shalt not abuse printf for puts */
		1345	\& puts ("wow, /etc/passwd is not there, expect problems. "
		1346	\& "if this is windows, they already arrived\en");
		1347	\& }
		1348	.Ve
		1349	.PP
		1350	.Vb 2
		1351	\& ...
		1352	\& ev_stat passwd;
		1353	.Ve
		1354	.PP
		1355	.Vb 2
		1356	\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
		1357	\& ev_stat_start (loop, &passwd);
		1358	.Ve
1124	.ie n .Sh """ev_idle"" \- when you've got nothing better to do"	1359	.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
1125	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do"	1360	.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
1126	.IX Subsection "ev_idle - when you've got nothing better to do"	1361	.IX Subsection "ev_idle - when you've got nothing better to do..."
1127	Idle watchers trigger events when there are no other events are pending	1362	Idle watchers trigger events when there are no other events are pending
1128	(prepare, check and other idle watchers do not count). That is, as long	1363	(prepare, check and other idle watchers do not count). That is, as long
1129	as your process is busy handling sockets or timeouts (or even signals,	1364	as your process is busy handling sockets or timeouts (or even signals,
1130	imagine) it will not be triggered. But when your process is idle all idle	1365	imagine) it will not be triggered. But when your process is idle all idle
1131	watchers are being called again and again, once per event loop iteration \-	1366	watchers are being called again and again, once per event loop iteration \-
…		…
1161	.Vb 3	1396	.Vb 3
1162	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1397	\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1163	\& ev_idle_init (idle_watcher, idle_cb);	1398	\& ev_idle_init (idle_watcher, idle_cb);
1164	\& ev_idle_start (loop, idle_cb);	1399	\& ev_idle_start (loop, idle_cb);
1165	.Ve	1400	.Ve
1166	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop"	1401	.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!"
1167	.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop"	1402	.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!"
1168	.IX Subsection "ev_prepare and ev_check - customise your event loop"	1403	.IX Subsection "ev_prepare and ev_check - customise your event loop!"
1169	Prepare and check watchers are usually (but not always) used in tandem:	1404	Prepare and check watchers are usually (but not always) used in tandem:
1170	prepare watchers get invoked before the process blocks and check watchers	1405	prepare watchers get invoked before the process blocks and check watchers
1171	afterwards.	1406	afterwards.
1172	.PP	1407	.PP
		1408	You \fImust not\fR call \f(CW\(C`ev_loop\(C'\fR or similar functions that enter
		1409	the current event loop from either \f(CW\(C`ev_prepare\(C'\fR or \f(CW\(C`ev_check\(C'\fR
		1410	watchers. Other loops than the current one are fine, however. The
		1411	rationale behind this is that you do not need to check for recursion in
		1412	those watchers, i.e. the sequence will always be \f(CW\(C`ev_prepare\(C'\fR, blocking,
		1413	\&\f(CW\(C`ev_check\(C'\fR so if you have one watcher of each kind they will always be
		1414	called in pairs bracketing the blocking call.
		1415	.PP
1173	Their main purpose is to integrate other event mechanisms into libev and	1416	Their main purpose is to integrate other event mechanisms into libev and
1174	their use is somewhat advanced. This could be used, for example, to track	1417	their use is somewhat advanced. This could be used, for example, to track
1175	variable changes, implement your own watchers, integrate net-snmp or a	1418	variable changes, implement your own watchers, integrate net-snmp or a
1176	coroutine library and lots more.	1419	coroutine library and lots more. They are also occasionally useful if
		1420	you cache some data and want to flush it before blocking (for example,
		1421	in X programs you might want to do an \f(CW\(C`XFlush ()\(C'\fR in an \f(CW\(C`ev_prepare\(C'\fR
		1422	watcher).
1177	.PP	1423	.PP
1178	This is done by examining in each prepare call which file descriptors need	1424	This is done by examining in each prepare call which file descriptors need
1179	to be watched by the other library, registering \f(CW\(C`ev_io\(C'\fR watchers for	1425	to be watched by the other library, registering \f(CW\(C`ev_io\(C'\fR watchers for
1180	them and starting an \f(CW\(C`ev_timer\(C'\fR watcher for any timeouts (many libraries	1426	them and starting an \f(CW\(C`ev_timer\(C'\fR watcher for any timeouts (many libraries
1181	provide just this functionality). Then, in the check watcher you check for	1427	provide just this functionality). Then, in the check watcher you check for
…		…
1200	.PD	1446	.PD
1201	Initialises and configures the prepare or check watcher \- they have no	1447	Initialises and configures the prepare or check watcher \- they have no
1202	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR	1448	parameters of any kind. There are \f(CW\(C`ev_prepare_set\(C'\fR and \f(CW\(C`ev_check_set\(C'\fR
1203	macros, but using them is utterly, utterly and completely pointless.	1449	macros, but using them is utterly, utterly and completely pointless.
1204	.PP	1450	.PP
1205	Example: TODO.	1451	Example: To include a library such as adns, you would add \s-1IO\s0 watchers
		1452	and a timeout watcher in a prepare handler, as required by libadns, and
		1453	in a check watcher, destroy them and call into libadns. What follows is
		1454	pseudo-code only of course:
		1455	.PP
		1456	.Vb 2
		1457	\& static ev_io iow [nfd];
		1458	\& static ev_timer tw;
		1459	.Ve
		1460	.PP
		1461	.Vb 9
		1462	\& static void
		1463	\& io_cb (ev_loop loop, ev_io w, int revents)
		1464	\& {
		1465	\& // set the relevant poll flags
		1466	\& // could also call adns_processreadable etc. here
		1467	\& struct pollfd fd = (struct pollfd )w->data;
		1468	\& if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1469	\& if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1470	\& }
		1471	.Ve
		1472	.PP
		1473	.Vb 7
		1474	\& // create io watchers for each fd and a timer before blocking
		1475	\& static void
		1476	\& adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
		1477	\& {
		1478	\& int timeout = 3600000;truct pollfd fds [nfd];
		1479	\& // actual code will need to loop here and realloc etc.
		1480	\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
		1481	.Ve
		1482	.PP
		1483	.Vb 3
		1484	\& /* the callback is illegal, but won't be called as we stop during check */
		1485	\& ev_timer_init (&tw, 0, timeout * 1e-3);
		1486	\& ev_timer_start (loop, &tw);
		1487	.Ve
		1488	.PP
		1489	.Vb 6
		1490	\& // create on ev_io per pollfd
		1491	\& for (int i = 0; i < nfd; ++i)
		1492	\& {
		1493	\& ev_io_init (iow + i, io_cb, fds [i].fd,
		1494	\& ((fds [i].events & POLLIN ? EV_READ : 0)
		1495	\& \| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
		1496	.Ve
		1497	.PP
		1498	.Vb 5
		1499	\& fds [i].revents = 0;
		1500	\& iow [i].data = fds + i;
		1501	\& ev_io_start (loop, iow + i);
		1502	\& }
		1503	\& }
		1504	.Ve
		1505	.PP
		1506	.Vb 5
		1507	\& // stop all watchers after blocking
		1508	\& static void
		1509	\& adns_check_cb (ev_loop loop, ev_check w, int revents)
		1510	\& {
		1511	\& ev_timer_stop (loop, &tw);
		1512	.Ve
		1513	.PP
		1514	.Vb 2
		1515	\& for (int i = 0; i < nfd; ++i)
		1516	\& ev_io_stop (loop, iow + i);
		1517	.Ve
		1518	.PP
		1519	.Vb 2
		1520	\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1521	\& }
		1522	.Ve
1206	.ie n .Sh """ev_embed"" \- when one backend isn't enough"	1523	.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1207	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough"	1524	.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1208	.IX Subsection "ev_embed - when one backend isn't enough"	1525	.IX Subsection "ev_embed - when one backend isn't enough..."
1209	This is a rather advanced watcher type that lets you embed one event loop	1526	This is a rather advanced watcher type that lets you embed one event loop
1210	into another.	1527	into another (currently only \f(CW\(C`ev_io\(C'\fR events are supported in the embedded
		1528	loop, other types of watchers might be handled in a delayed or incorrect
		1529	fashion and must not be used).
1211	.PP	1530	.PP
1212	There are primarily two reasons you would want that: work around bugs and	1531	There are primarily two reasons you would want that: work around bugs and
1213	prioritise I/O.	1532	prioritise I/O.
1214	.PP	1533	.PP
1215	As an example for a bug workaround, the kqueue backend might only support	1534	As an example for a bug workaround, the kqueue backend might only support
…		…
1223	As for prioritising I/O: rarely you have the case where some fds have	1542	As for prioritising I/O: rarely you have the case where some fds have
1224	to be watched and handled very quickly (with low latency), and even	1543	to be watched and handled very quickly (with low latency), and even
1225	priorities and idle watchers might have too much overhead. In this case	1544	priorities and idle watchers might have too much overhead. In this case
1226	you would put all the high priority stuff in one loop and all the rest in	1545	you would put all the high priority stuff in one loop and all the rest in
1227	a second one, and embed the second one in the first.	1546	a second one, and embed the second one in the first.
		1547	.PP
		1548	As long as the watcher is active, the callback will be invoked every time
		1549	there might be events pending in the embedded loop. The callback must then
		1550	call \f(CW\(C`ev_embed_sweep (mainloop, watcher)\(C'\fR to make a single sweep and invoke
		1551	their callbacks (you could also start an idle watcher to give the embedded
		1552	loop strictly lower priority for example). You can also set the callback
		1553	to \f(CW0\fR, in which case the embed watcher will automatically execute the
		1554	embedded loop sweep.
1228	.PP	1555	.PP
1229	As long as the watcher is started it will automatically handle events. The	1556	As long as the watcher is started it will automatically handle events. The
1230	callback will be invoked whenever some events have been handled. You can	1557	callback will be invoked whenever some events have been handled. You can
1231	set the callback to \f(CW0\fR to avoid having to specify one if you are not	1558	set the callback to \f(CW0\fR to avoid having to specify one if you are not
1232	interested in that.	1559	interested in that.
…		…
1267	\& ev_embed_start (loop_hi, &embed);	1594	\& ev_embed_start (loop_hi, &embed);
1268	\& }	1595	\& }
1269	\& else	1596	\& else
1270	\& loop_lo = loop_hi;	1597	\& loop_lo = loop_hi;
1271	.Ve	1598	.Ve
1272	.IP "ev_embed_init (ev_embed , callback, struct ev_loop loop)" 4	1599	.IP "ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)" 4
1273	.IX Item "ev_embed_init (ev_embed , callback, struct ev_loop loop)"	1600	.IX Item "ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)"
1274	.PD 0	1601	.PD 0
1275	.IP "ev_embed_set (ev_embed , callback, struct ev_loop loop)" 4	1602	.IP "ev_embed_set (ev_embed , callback, struct ev_loop embedded_loop)" 4
1276	.IX Item "ev_embed_set (ev_embed , callback, struct ev_loop loop)"	1603	.IX Item "ev_embed_set (ev_embed , callback, struct ev_loop embedded_loop)"
1277	.PD	1604	.PD
1278	Configures the watcher to embed the given loop, which must be embeddable.	1605	Configures the watcher to embed the given loop, which must be
		1606	embeddable. If the callback is \f(CW0\fR, then \f(CW\(C`ev_embed_sweep\(C'\fR will be
		1607	invoked automatically, otherwise it is the responsibility of the callback
		1608	to invoke it (it will continue to be called until the sweep has been done,
		1609	if you do not want thta, you need to temporarily stop the embed watcher).
		1610	.IP "ev_embed_sweep (loop, ev_embed *)" 4
		1611	.IX Item "ev_embed_sweep (loop, ev_embed *)"
		1612	Make a single, non-blocking sweep over the embedded loop. This works
		1613	similarly to \f(CW\(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\(C'\fR, but in the most
		1614	apropriate way for embedded loops.
		1615	.IP "struct ev_loop *loop [read\-only]" 4
		1616	.IX Item "struct ev_loop *loop [read-only]"
		1617	The embedded event loop.
1279	.SH "OTHER FUNCTIONS"	1618	.SH "OTHER FUNCTIONS"
1280	.IX Header "OTHER FUNCTIONS"	1619	.IX Header "OTHER FUNCTIONS"
1281	There are some other functions of possible interest. Described. Here. Now.	1620	There are some other functions of possible interest. Described. Here. Now.
1282	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4	1621	.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
1283	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"	1622	.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
…		…
1312	.Ve	1651	.Ve
1313	.Sp	1652	.Sp
1314	.Vb 1	1653	.Vb 1
1315	\& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	1654	\& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
1316	.Ve	1655	.Ve
1317	.IP "ev_feed_event (loop, watcher, int events)" 4	1656	.IP "ev_feed_event (ev_loop , watcher , int revents)" 4
1318	.IX Item "ev_feed_event (loop, watcher, int events)"	1657	.IX Item "ev_feed_event (ev_loop , watcher , int revents)"
1319	Feeds the given event set into the event loop, as if the specified event	1658	Feeds the given event set into the event loop, as if the specified event
1320	had happened for the specified watcher (which must be a pointer to an	1659	had happened for the specified watcher (which must be a pointer to an
1321	initialised but not necessarily started event watcher).	1660	initialised but not necessarily started event watcher).
1322	.IP "ev_feed_fd_event (loop, int fd, int revents)" 4	1661	.IP "ev_feed_fd_event (ev_loop *, int fd, int revents)" 4
1323	.IX Item "ev_feed_fd_event (loop, int fd, int revents)"	1662	.IX Item "ev_feed_fd_event (ev_loop *, int fd, int revents)"
1324	Feed an event on the given fd, as if a file descriptor backend detected	1663	Feed an event on the given fd, as if a file descriptor backend detected
1325	the given events it.	1664	the given events it.
1326	.IP "ev_feed_signal_event (loop, int signum)" 4	1665	.IP "ev_feed_signal_event (ev_loop *loop, int signum)" 4
1327	.IX Item "ev_feed_signal_event (loop, int signum)"	1666	.IX Item "ev_feed_signal_event (ev_loop *loop, int signum)"
1328	Feed an event as if the given signal occured (loop must be the default loop!).	1667	Feed an event as if the given signal occured (\f(CW\(C`loop\(C'\fR must be the default
		1668	loop!).
1329	.SH "LIBEVENT EMULATION"	1669	.SH "LIBEVENT EMULATION"
1330	.IX Header "LIBEVENT EMULATION"	1670	.IX Header "LIBEVENT EMULATION"
1331	Libev offers a compatibility emulation layer for libevent. It cannot	1671	Libev offers a compatibility emulation layer for libevent. It cannot
1332	emulate the internals of libevent, so here are some usage hints:	1672	emulate the internals of libevent, so here are some usage hints:
1333	.IP "* Use it by including <event.h>, as usual." 4	1673	.IP "* Use it by including <event.h>, as usual." 4
…		…
1344	.IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4	1684	.IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4
1345	.IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library."	1685	.IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library."
1346	.PD	1686	.PD
1347	.SH "\*(C+ SUPPORT"	1687	.SH "\*(C+ SUPPORT"
1348	.IX Header " SUPPORT"	1688	.IX Header " SUPPORT"
1349	\&\s-1TBD\s0.	1689	Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow
		1690	you to use some convinience methods to start/stop watchers and also change
		1691	the callback model to a model using method callbacks on objects.
		1692	.PP
		1693	To use it,
		1694	.PP
		1695	.Vb 1
		1696	\& #include <ev++.h>
		1697	.Ve
		1698	.PP
		1699	(it is not installed by default). This automatically includes \fIev.h\fR
		1700	and puts all of its definitions (many of them macros) into the global
		1701	namespace. All \(C+ specific things are put into the \f(CW\(C`ev\*(C'\fR namespace.
		1702	.PP
		1703	It should support all the same embedding options as \fIev.h\fR, most notably
		1704	\&\f(CW\(C`EV_MULTIPLICITY\(C'\fR.
		1705	.PP
		1706	Here is a list of things available in the \f(CW\(C`ev\(C'\fR namespace:
		1707	.ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4
		1708	.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4
		1709	.IX Item "ev::READ, ev::WRITE etc."
		1710	These are just enum values with the same values as the \f(CW\(C`EV_READ\(C'\fR etc.
		1711	macros from \fIev.h\fR.
		1712	.ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4
		1713	.el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4
		1714	.IX Item "ev::tstamp, ev::now"
		1715	Aliases to the same types/functions as with the \f(CW\(C`ev_\(C'\fR prefix.
		1716	.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
		1717	.el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4
		1718	.IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc."
		1719	For each \f(CW\(C`ev_TYPE\(C'\fR watcher in \fIev.h\fR there is a corresponding class of
		1720	the same name in the \f(CW\(C`ev\(C'\fR namespace, with the exception of \f(CW\(C`ev_signal\(C'\fR
		1721	which is called \f(CW\(C`ev::sig\(C'\fR to avoid clashes with the \f(CW\(C`signal\(C'\fR macro
		1722	defines by many implementations.
		1723	.Sp
		1724	All of those classes have these methods:
		1725	.RS 4
		1726	.IP "ev::TYPE::TYPE (object , object::method )" 4
		1727	.IX Item "ev::TYPE::TYPE (object , object::method )"
		1728	.PD 0
		1729	.IP "ev::TYPE::TYPE (object , object::method , struct ev_loop *)" 4
		1730	.IX Item "ev::TYPE::TYPE (object , object::method , struct ev_loop *)"
		1731	.IP "ev::TYPE::~TYPE" 4
		1732	.IX Item "ev::TYPE::~TYPE"
		1733	.PD
		1734	The constructor takes a pointer to an object and a method pointer to
		1735	the event handler callback to call in this class. The constructor calls
		1736	\&\f(CW\(C`ev_init\(C'\fR for you, which means you have to call the \f(CW\(C`set\(C'\fR method
		1737	before starting it. If you do not specify a loop then the constructor
		1738	automatically associates the default loop with this watcher.
		1739	.Sp
		1740	The destructor automatically stops the watcher if it is active.
		1741	.IP "w\->set (struct ev_loop *)" 4
		1742	.IX Item "w->set (struct ev_loop *)"
		1743	Associates a different \f(CW\(C`struct ev_loop\(C'\fR with this watcher. You can only
		1744	do this when the watcher is inactive (and not pending either).
		1745	.IP "w\->set ([args])" 4
		1746	.IX Item "w->set ([args])"
		1747	Basically the same as \f(CW\(C`ev_TYPE_set\(C'\fR, with the same args. Must be
		1748	called at least once. Unlike the C counterpart, an active watcher gets
		1749	automatically stopped and restarted.
		1750	.IP "w\->start ()" 4
		1751	.IX Item "w->start ()"
		1752	Starts the watcher. Note that there is no \f(CW\(C`loop\(C'\fR argument as the
		1753	constructor already takes the loop.
		1754	.IP "w\->stop ()" 4
		1755	.IX Item "w->stop ()"
		1756	Stops the watcher if it is active. Again, no \f(CW\(C`loop\(C'\fR argument.
		1757	.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4
		1758	.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4
		1759	.IX Item "w->again () ev::timer, ev::periodic only"
		1760	For \f(CW\(C`ev::timer\(C'\fR and \f(CW\(C`ev::periodic\(C'\fR, this invokes the corresponding
		1761	\&\f(CW\(C`ev_TYPE_again\(C'\fR function.
		1762	.ie n .IP "w\->sweep () ""ev::embed"" only" 4
		1763	.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
		1764	.IX Item "w->sweep () ev::embed only"
		1765	Invokes \f(CW\(C`ev_embed_sweep\(C'\fR.
		1766	.ie n .IP "w\->update () ""ev::stat"" only" 4
		1767	.el .IP "w\->update () \f(CWev::stat\fR only" 4
		1768	.IX Item "w->update () ev::stat only"
		1769	Invokes \f(CW\(C`ev_stat_stat\(C'\fR.
		1770	.RE
		1771	.RS 4
		1772	.RE
		1773	.PP
		1774	Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
		1775	the constructor.
		1776	.PP
		1777	.Vb 4
		1778	\& class myclass
		1779	\& {
		1780	\& ev_io io; void io_cb (ev::io &w, int revents);
		1781	\& ev_idle idle void idle_cb (ev::idle &w, int revents);
		1782	.Ve
		1783	.PP
		1784	.Vb 2
		1785	\& myclass ();
		1786	\& }
		1787	.Ve
		1788	.PP
		1789	.Vb 6
		1790	\& myclass::myclass (int fd)
		1791	\& : io (this, &myclass::io_cb),
		1792	\& idle (this, &myclass::idle_cb)
		1793	\& {
		1794	\& io.start (fd, ev::READ);
		1795	\& }
		1796	.Ve
		1797	.SH "EMBEDDING"
		1798	.IX Header "EMBEDDING"
		1799	Libev can (and often is) directly embedded into host
		1800	applications. Examples of applications that embed it include the Deliantra
		1801	Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe)
		1802	and rxvt\-unicode.
		1803	.PP
		1804	The goal is to enable you to just copy the neecssary files into your
		1805	source directory without having to change even a single line in them, so
		1806	you can easily upgrade by simply copying (or having a checked-out copy of
		1807	libev somewhere in your source tree).
		1808	.Sh "\s-1FILESETS\s0"
		1809	.IX Subsection "FILESETS"
		1810	Depending on what features you need you need to include one or more sets of files
		1811	in your app.
		1812	.PP
		1813	\fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR
		1814	.IX Subsection "CORE EVENT LOOP"
		1815	.PP
		1816	To include only the libev core (all the \f(CW\(C`ev_\*(C'\fR functions), with manual
		1817	configuration (no autoconf):
		1818	.PP
		1819	.Vb 2
		1820	\& #define EV_STANDALONE 1
		1821	\& #include "ev.c"
		1822	.Ve
		1823	.PP
		1824	This will automatically include \fIev.h\fR, too, and should be done in a
		1825	single C source file only to provide the function implementations. To use
		1826	it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best
		1827	done by writing a wrapper around \fIev.h\fR that you can include instead and
		1828	where you can put other configuration options):
		1829	.PP
		1830	.Vb 2
		1831	\& #define EV_STANDALONE 1
		1832	\& #include "ev.h"
		1833	.Ve
		1834	.PP
		1835	Both header files and implementation files can be compiled with a \*(C+
		1836	compiler (at least, thats a stated goal, and breakage will be treated
		1837	as a bug).
		1838	.PP
		1839	You need the following files in your source tree, or in a directory
		1840	in your include path (e.g. in libev/ when using \-Ilibev):
		1841	.PP
		1842	.Vb 4
		1843	\& ev.h
		1844	\& ev.c
		1845	\& ev_vars.h
		1846	\& ev_wrap.h
		1847	.Ve
		1848	.PP
		1849	.Vb 1
		1850	\& ev_win32.c required on win32 platforms only
		1851	.Ve
		1852	.PP
		1853	.Vb 5
		1854	\& ev_select.c only when select backend is enabled (which is by default)
		1855	\& ev_poll.c only when poll backend is enabled (disabled by default)
		1856	\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
		1857	\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
		1858	\& ev_port.c only when the solaris port backend is enabled (disabled by default)
		1859	.Ve
		1860	.PP
		1861	\&\fIev.c\fR includes the backend files directly when enabled, so you only need
		1862	to compile this single file.
		1863	.PP
		1864	\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR
		1865	.IX Subsection "LIBEVENT COMPATIBILITY API"
		1866	.PP
		1867	To include the libevent compatibility \s-1API\s0, also include:
		1868	.PP
		1869	.Vb 1
		1870	\& #include "event.c"
		1871	.Ve
		1872	.PP
		1873	in the file including \fIev.c\fR, and:
		1874	.PP
		1875	.Vb 1
		1876	\& #include "event.h"
		1877	.Ve
		1878	.PP
		1879	in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR.
		1880	.PP
		1881	You need the following additional files for this:
		1882	.PP
		1883	.Vb 2
		1884	\& event.h
		1885	\& event.c
		1886	.Ve
		1887	.PP
		1888	\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR
		1889	.IX Subsection "AUTOCONF SUPPORT"
		1890	.PP
		1891	Instead of using \f(CW\(C`EV_STANDALONE=1\(C'\fR and providing your config in
		1892	whatever way you want, you can also \f(CW\(C`m4_include([libev.m4])\(C'\fR in your
		1893	\&\fIconfigure.ac\fR and leave \f(CW\(C`EV_STANDALONE\(C'\fR undefined. \fIev.c\fR will then
		1894	include \fIconfig.h\fR and configure itself accordingly.
		1895	.PP
		1896	For this of course you need the m4 file:
		1897	.PP
		1898	.Vb 1
		1899	\& libev.m4
		1900	.Ve
		1901	.Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0"
		1902	.IX Subsection "PREPROCESSOR SYMBOLS/MACROS"
		1903	Libev can be configured via a variety of preprocessor symbols you have to define
		1904	before including any of its files. The default is not to build for multiplicity
		1905	and only include the select backend.
		1906	.IP "\s-1EV_STANDALONE\s0" 4
		1907	.IX Item "EV_STANDALONE"
		1908	Must always be \f(CW1\fR if you do not use autoconf configuration, which
		1909	keeps libev from including \fIconfig.h\fR, and it also defines dummy
		1910	implementations for some libevent functions (such as logging, which is not
		1911	supported). It will also not define any of the structs usually found in
		1912	\&\fIevent.h\fR that are not directly supported by the libev core alone.
		1913	.IP "\s-1EV_USE_MONOTONIC\s0" 4
		1914	.IX Item "EV_USE_MONOTONIC"
		1915	If defined to be \f(CW1\fR, libev will try to detect the availability of the
		1916	monotonic clock option at both compiletime and runtime. Otherwise no use
		1917	of the monotonic clock option will be attempted. If you enable this, you
		1918	usually have to link against librt or something similar. Enabling it when
		1919	the functionality isn't available is safe, though, althoguh you have
		1920	to make sure you link against any libraries where the \f(CW\(C`clock_gettime\(C'\fR
		1921	function is hiding in (often \fI\-lrt\fR).
		1922	.IP "\s-1EV_USE_REALTIME\s0" 4
		1923	.IX Item "EV_USE_REALTIME"
		1924	If defined to be \f(CW1\fR, libev will try to detect the availability of the
		1925	realtime clock option at compiletime (and assume its availability at
		1926	runtime if successful). Otherwise no use of the realtime clock option will
		1927	be attempted. This effectively replaces \f(CW\(C`gettimeofday\(C'\fR by \f(CW\*(C`clock_get
		1928	(CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries
		1929	in the description of \f(CW\(C`EV_USE_MONOTONIC\(C'\fR, though.
		1930	.IP "\s-1EV_USE_SELECT\s0" 4
		1931	.IX Item "EV_USE_SELECT"
		1932	If undefined or defined to be \f(CW1\fR, libev will compile in support for the
		1933	\&\f(CW\(C`select\(C'\fR(2) backend. No attempt at autodetection will be done: if no
		1934	other method takes over, select will be it. Otherwise the select backend
		1935	will not be compiled in.
		1936	.IP "\s-1EV_SELECT_USE_FD_SET\s0" 4
		1937	.IX Item "EV_SELECT_USE_FD_SET"
		1938	If defined to \f(CW1\fR, then the select backend will use the system \f(CW\(C`fd_set\(C'\fR
		1939	structure. This is useful if libev doesn't compile due to a missing
		1940	\&\f(CW\(C`NFDBITS\(C'\fR or \f(CW\(C`fd_mask\(C'\fR definition or it misguesses the bitset layout on
		1941	exotic systems. This usually limits the range of file descriptors to some
		1942	low limit such as 1024 or might have other limitations (winsocket only
		1943	allows 64 sockets). The \f(CW\(C`FD_SETSIZE\(C'\fR macro, set before compilation, might
		1944	influence the size of the \f(CW\(C`fd_set\(C'\fR used.
		1945	.IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4
		1946	.IX Item "EV_SELECT_IS_WINSOCKET"
		1947	When defined to \f(CW1\fR, the select backend will assume that
		1948	select/socket/connect etc. don't understand file descriptors but
		1949	wants osf handles on win32 (this is the case when the select to
		1950	be used is the winsock select). This means that it will call
		1951	\&\f(CW\(C`_get_osfhandle\(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise,
		1952	it is assumed that all these functions actually work on fds, even
		1953	on win32. Should not be defined on non\-win32 platforms.
		1954	.IP "\s-1EV_USE_POLL\s0" 4
		1955	.IX Item "EV_USE_POLL"
		1956	If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\(C`poll\(C'\fR(2)
		1957	backend. Otherwise it will be enabled on non\-win32 platforms. It
		1958	takes precedence over select.
		1959	.IP "\s-1EV_USE_EPOLL\s0" 4
		1960	.IX Item "EV_USE_EPOLL"
		1961	If defined to be \f(CW1\fR, libev will compile in support for the Linux
		1962	\&\f(CW\(C`epoll\(C'\fR(7) backend. Its availability will be detected at runtime,
		1963	otherwise another method will be used as fallback. This is the
		1964	preferred backend for GNU/Linux systems.
		1965	.IP "\s-1EV_USE_KQUEUE\s0" 4
		1966	.IX Item "EV_USE_KQUEUE"
		1967	If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style
		1968	\&\f(CW\(C`kqueue\(C'\fR(2) backend. Its actual availability will be detected at runtime,
		1969	otherwise another method will be used as fallback. This is the preferred
		1970	backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only
		1971	supports some types of fds correctly (the only platform we found that
		1972	supports ptys for example was NetBSD), so kqueue might be compiled in, but
		1973	not be used unless explicitly requested. The best way to use it is to find
		1974	out whether kqueue supports your type of fd properly and use an embedded
		1975	kqueue loop.
		1976	.IP "\s-1EV_USE_PORT\s0" 4
		1977	.IX Item "EV_USE_PORT"
		1978	If defined to be \f(CW1\fR, libev will compile in support for the Solaris
		1979	10 port style backend. Its availability will be detected at runtime,
		1980	otherwise another method will be used as fallback. This is the preferred
		1981	backend for Solaris 10 systems.
		1982	.IP "\s-1EV_USE_DEVPOLL\s0" 4
		1983	.IX Item "EV_USE_DEVPOLL"
		1984	reserved for future expansion, works like the \s-1USE\s0 symbols above.
		1985	.IP "\s-1EV_H\s0" 4
		1986	.IX Item "EV_H"
		1987	The name of the \fIev.h\fR header file used to include it. The default if
		1988	undefined is \f(CW\(C`<ev.h>\(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
		1989	can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
		1990	.IP "\s-1EV_CONFIG_H\s0" 4
		1991	.IX Item "EV_CONFIG_H"
		1992	If \f(CW\(C`EV_STANDALONE\(C'\fR isn't \f(CW1\fR, this variable can be used to override
		1993	\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
		1994	\&\f(CW\(C`EV_H\(C'\fR, above.
		1995	.IP "\s-1EV_EVENT_H\s0" 4
		1996	.IX Item "EV_EVENT_H"
		1997	Similarly to \f(CW\(C`EV_H\(C'\fR, this macro can be used to override \fIevent.c\fR's idea
		1998	of how the \fIevent.h\fR header can be found.
		1999	.IP "\s-1EV_PROTOTYPES\s0" 4
		2000	.IX Item "EV_PROTOTYPES"
		2001	If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
		2002	prototypes, but still define all the structs and other symbols. This is
		2003	occasionally useful if you want to provide your own wrapper functions
		2004	around libev functions.
		2005	.IP "\s-1EV_MULTIPLICITY\s0" 4
		2006	.IX Item "EV_MULTIPLICITY"
		2007	If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
		2008	will have the \f(CW\(C`struct ev_loop \*(C'\fR as first argument, and you can create
		2009	additional independent event loops. Otherwise there will be no support
		2010	for multiple event loops and there is no first event loop pointer
		2011	argument. Instead, all functions act on the single default loop.
		2012	.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
		2013	.IX Item "EV_PERIODIC_ENABLE"
		2014	If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
		2015	defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
		2016	code.
		2017	.IP "\s-1EV_EMBED_ENABLE\s0" 4
		2018	.IX Item "EV_EMBED_ENABLE"
		2019	If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
		2020	defined to be \f(CW0\fR, then they are not.
		2021	.IP "\s-1EV_STAT_ENABLE\s0" 4
		2022	.IX Item "EV_STAT_ENABLE"
		2023	If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
		2024	defined to be \f(CW0\fR, then they are not.
		2025	.IP "\s-1EV_MINIMAL\s0" 4
		2026	.IX Item "EV_MINIMAL"
		2027	If you need to shave off some kilobytes of code at the expense of some
		2028	speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
		2029	some inlining decisions, saves roughly 30% codesize of amd64.
		2030	.IP "\s-1EV_COMMON\s0" 4
		2031	.IX Item "EV_COMMON"
		2032	By default, all watchers have a \f(CW\(C`void data\*(C'\fR member. By redefining
		2033	this macro to a something else you can include more and other types of
		2034	members. You have to define it each time you include one of the files,
		2035	though, and it must be identical each time.
		2036	.Sp
		2037	For example, the perl \s-1EV\s0 module uses something like this:
		2038	.Sp
		2039	.Vb 3
		2040	\& #define EV_COMMON \e
		2041	\& SV self; / contains this struct */ \e
		2042	\& SV cb_sv, fh /* note no trailing ";" */
		2043	.Ve
		2044	.IP "\s-1EV_CB_DECLARE\s0 (type)" 4
		2045	.IX Item "EV_CB_DECLARE (type)"
		2046	.PD 0
		2047	.IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4
		2048	.IX Item "EV_CB_INVOKE (watcher, revents)"
		2049	.IP "ev_set_cb (ev, cb)" 4
		2050	.IX Item "ev_set_cb (ev, cb)"
		2051	.PD
		2052	Can be used to change the callback member declaration in each watcher,
		2053	and the way callbacks are invoked and set. Must expand to a struct member
		2054	definition and a statement, respectively. See the \fIev.v\fR header file for
		2055	their default definitions. One possible use for overriding these is to
		2056	avoid the \f(CW\(C`struct ev_loop \*(C'\fR as first argument in all cases, or to use
		2057	method calls instead of plain function calls in \*(C+.
		2058	.Sh "\s-1EXAMPLES\s0"
		2059	.IX Subsection "EXAMPLES"
		2060	For a real-world example of a program the includes libev
		2061	verbatim, you can have a look at the \s-1EV\s0 perl module
		2062	(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
		2063	the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public
		2064	interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
		2065	will be compiled. It is pretty complex because it provides its own header
		2066	file.
		2067	.Sp
		2068	The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
		2069	that everybody includes and which overrides some autoconf choices:
		2070	.Sp
		2071	.Vb 4
		2072	\& #define EV_USE_POLL 0
		2073	\& #define EV_MULTIPLICITY 0
		2074	\& #define EV_PERIODICS 0
		2075	\& #define EV_CONFIG_H <config.h>
		2076	.Ve
		2077	.Sp
		2078	.Vb 1
		2079	\& #include "ev++.h"
		2080	.Ve
		2081	.Sp
		2082	And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled:
		2083	.Sp
		2084	.Vb 2
		2085	\& #include "ev_cpp.h"
		2086	\& #include "ev.c"
		2087	.Ve
		2088	.SH "COMPLEXITIES"
		2089	.IX Header "COMPLEXITIES"
		2090	In this section the complexities of (many of) the algorithms used inside
		2091	libev will be explained. For complexity discussions about backends see the
		2092	documentation for \f(CW\(C`ev_default_init\(C'\fR.
		2093	.RS 4
		2094	.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
		2095	.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
		2096	.PD 0
		2097	.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4
		2098	.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
		2099	.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
		2100	.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
		2101	.IP "Stopping check/prepare/idle watchers: O(1)" 4
		2102	.IX Item "Stopping check/prepare/idle watchers: O(1)"
		2103	.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4
		2104	.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))"
		2105	.IP "Finding the next timer per loop iteration: O(1)" 4
		2106	.IX Item "Finding the next timer per loop iteration: O(1)"
		2107	.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
		2108	.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
		2109	.IP "Activating one watcher: O(1)" 4
		2110	.IX Item "Activating one watcher: O(1)"
		2111	.RE
		2112	.RS 4
		2113	.PD
1350	.SH "AUTHOR"	2114	.SH "AUTHOR"
1351	.IX Header "AUTHOR"	2115	.IX Header "AUTHOR"
1352	Marc Lehmann <libev@schmorp.de>.	2116	Marc Lehmann <libev@schmorp.de>.

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing libev/ev.3 (file contents): Revision 1.10 by root, Sat Nov 24 06:23:27 2007 UTC vs. Revision 1.23 by root, Tue Nov 27 08:20:42 2007 UTC

Diff Legend

Comparing libev/ev.3 (file contents):
Revision 1.10 by root, Sat Nov 24 06:23:27 2007 UTC vs.
Revision 1.23 by root, Tue Nov 27 08:20:42 2007 UTC