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Revision 1.163 by root, Sat May 31 23:19:23 2008 UTC vs.
Revision 1.176 by root, Mon Sep 8 17:24:39 2008 UTC

…		…
2		2
3	libev - a high performance full-featured event loop written in C	3	libev - a high performance full-featured event loop written in C
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	#include <ev.h>	7	#include <ev.h>
8		8
9	=head2 EXAMPLE PROGRAM	9	=head2 EXAMPLE PROGRAM
10		10
11	// a single header file is required	11	// a single header file is required
12	#include <ev.h>	12	#include <ev.h>
13		13
14	// every watcher type has its own typedef'd struct	14	// every watcher type has its own typedef'd struct
15	// with the name ev_<type>	15	// with the name ev_<type>
16	ev_io stdin_watcher;	16	ev_io stdin_watcher;
17	ev_timer timeout_watcher;	17	ev_timer timeout_watcher;
18		18
19	// all watcher callbacks have a similar signature	19	// all watcher callbacks have a similar signature
20	// this callback is called when data is readable on stdin	20	// this callback is called when data is readable on stdin
21	static void	21	static void
22	stdin_cb (EV_P_ struct ev_io *w, int revents)	22	stdin_cb (EV_P_ struct ev_io *w, int revents)
23	{	23	{
24	puts ("stdin ready");	24	puts ("stdin ready");
25	// for one-shot events, one must manually stop the watcher	25	// for one-shot events, one must manually stop the watcher
26	// with its corresponding stop function.	26	// with its corresponding stop function.
27	ev_io_stop (EV_A_ w);	27	ev_io_stop (EV_A_ w);
28		28
29	// this causes all nested ev_loop's to stop iterating	29	// this causes all nested ev_loop's to stop iterating
30	ev_unloop (EV_A_ EVUNLOOP_ALL);	30	ev_unloop (EV_A_ EVUNLOOP_ALL);
31	}	31	}
32		32
33	// another callback, this time for a time-out	33	// another callback, this time for a time-out
34	static void	34	static void
35	timeout_cb (EV_P_ struct ev_timer *w, int revents)	35	timeout_cb (EV_P_ struct ev_timer *w, int revents)
36	{	36	{
37	puts ("timeout");	37	puts ("timeout");
38	// this causes the innermost ev_loop to stop iterating	38	// this causes the innermost ev_loop to stop iterating
39	ev_unloop (EV_A_ EVUNLOOP_ONE);	39	ev_unloop (EV_A_ EVUNLOOP_ONE);
40	}	40	}
41		41
42	int	42	int
43	main (void)	43	main (void)
44	{	44	{
45	// use the default event loop unless you have special needs	45	// use the default event loop unless you have special needs
46	struct ev_loop *loop = ev_default_loop (0);	46	struct ev_loop *loop = ev_default_loop (0);
47		47
48	// initialise an io watcher, then start it	48	// initialise an io watcher, then start it
49	// this one will watch for stdin to become readable	49	// this one will watch for stdin to become readable
50	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);	50	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
51	ev_io_start (loop, &stdin_watcher);	51	ev_io_start (loop, &stdin_watcher);
52		52
53	// initialise a timer watcher, then start it	53	// initialise a timer watcher, then start it
54	// simple non-repeating 5.5 second timeout	54	// simple non-repeating 5.5 second timeout
55	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	55	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
56	ev_timer_start (loop, &timeout_watcher);	56	ev_timer_start (loop, &timeout_watcher);
57		57
58	// now wait for events to arrive	58	// now wait for events to arrive
59	ev_loop (loop, 0);	59	ev_loop (loop, 0);
60		60
61	// unloop was called, so exit	61	// unloop was called, so exit
62	return 0;	62	return 0;
63	}	63	}
64		64
65	=head1 DESCRIPTION	65	=head1 DESCRIPTION
66		66
67	The newest version of this document is also available as an html-formatted	67	The newest version of this document is also available as an html-formatted
68	web page you might find easier to navigate when reading it for the first	68	web page you might find easier to navigate when reading it for the first
…		…
178	not a problem.	178	not a problem.
179		179
180	Example: Make sure we haven't accidentally been linked against the wrong	180	Example: Make sure we haven't accidentally been linked against the wrong
181	version.	181	version.
182		182
183	assert (("libev version mismatch",	183	assert (("libev version mismatch",
184	ev_version_major () == EV_VERSION_MAJOR	184	ev_version_major () == EV_VERSION_MAJOR
185	&& ev_version_minor () >= EV_VERSION_MINOR));	185	&& ev_version_minor () >= EV_VERSION_MINOR));
186		186
187	=item unsigned int ev_supported_backends ()	187	=item unsigned int ev_supported_backends ()
188		188
189	Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*>	189	Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*>
190	value) compiled into this binary of libev (independent of their	190	value) compiled into this binary of libev (independent of their
…		…
192	a description of the set values.	192	a description of the set values.
193		193
194	Example: make sure we have the epoll method, because yeah this is cool and	194	Example: make sure we have the epoll method, because yeah this is cool and
195	a must have and can we have a torrent of it please!!!11	195	a must have and can we have a torrent of it please!!!11
196		196
197	assert (("sorry, no epoll, no sex",	197	assert (("sorry, no epoll, no sex",
198	ev_supported_backends () & EVBACKEND_EPOLL));	198	ev_supported_backends () & EVBACKEND_EPOLL));
199		199
200	=item unsigned int ev_recommended_backends ()	200	=item unsigned int ev_recommended_backends ()
201		201
202	Return the set of all backends compiled into this binary of libev and also	202	Return the set of all backends compiled into this binary of libev and also
203	recommended for this platform. This set is often smaller than the one	203	recommended for this platform. This set is often smaller than the one
…		…
466	backends will be tried (in the reverse order as listed here). If none are	466	backends will be tried (in the reverse order as listed here). If none are
467	specified, all backends in C<ev_recommended_backends ()> will be tried.	467	specified, all backends in C<ev_recommended_backends ()> will be tried.
468		468
469	The most typical usage is like this:	469	The most typical usage is like this:
470		470
471	if (!ev_default_loop (0))	471	if (!ev_default_loop (0))
472	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");	472	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
473		473
474	Restrict libev to the select and poll backends, and do not allow	474	Restrict libev to the select and poll backends, and do not allow
475	environment settings to be taken into account:	475	environment settings to be taken into account:
476		476
477	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);	477	ev_default_loop (EVBACKEND_POLL \| EVBACKEND_SELECT \| EVFLAG_NOENV);
478		478
479	Use whatever libev has to offer, but make sure that kqueue is used if	479	Use whatever libev has to offer, but make sure that kqueue is used if
480	available (warning, breaks stuff, best use only with your own private	480	available (warning, breaks stuff, best use only with your own private
481	event loop and only if you know the OS supports your types of fds):	481	event loop and only if you know the OS supports your types of fds):
482		482
483	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);	483	ev_default_loop (ev_recommended_backends () \| EVBACKEND_KQUEUE);
484		484
485	=item struct ev_loop *ev_loop_new (unsigned int flags)	485	=item struct ev_loop *ev_loop_new (unsigned int flags)
486		486
487	Similar to C<ev_default_loop>, but always creates a new event loop that is	487	Similar to C<ev_default_loop>, but always creates a new event loop that is
488	always distinct from the default loop. Unlike the default loop, it cannot	488	always distinct from the default loop. Unlike the default loop, it cannot
…		…
493	libev with threads is indeed to create one loop per thread, and using the	493	libev with threads is indeed to create one loop per thread, and using the
494	default loop in the "main" or "initial" thread.	494	default loop in the "main" or "initial" thread.
495		495
496	Example: Try to create a event loop that uses epoll and nothing else.	496	Example: Try to create a event loop that uses epoll and nothing else.
497		497
498	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	498	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
499	if (!epoller)	499	if (!epoller)
500	fatal ("no epoll found here, maybe it hides under your chair");	500	fatal ("no epoll found here, maybe it hides under your chair");
501		501
502	=item ev_default_destroy ()	502	=item ev_default_destroy ()
503		503
504	Destroys the default loop again (frees all memory and kernel state	504	Destroys the default loop again (frees all memory and kernel state
505	etc.). None of the active event watchers will be stopped in the normal	505	etc.). None of the active event watchers will be stopped in the normal
…		…
573	received events and started processing them. This timestamp does not	573	received events and started processing them. This timestamp does not
574	change as long as callbacks are being processed, and this is also the base	574	change as long as callbacks are being processed, and this is also the base
575	time used for relative timers. You can treat it as the timestamp of the	575	time used for relative timers. You can treat it as the timestamp of the
576	event occurring (or more correctly, libev finding out about it).	576	event occurring (or more correctly, libev finding out about it).
577		577
		578	=item ev_now_update (loop)
		579
		580	Establishes the current time by querying the kernel, updating the time
		581	returned by C<ev_now ()> in the progress. This is a costly operation and
		582	is usually done automatically within C<ev_loop ()>.
		583
		584	This function is rarely useful, but when some event callback runs for a
		585	very long time without entering the event loop, updating libev's idea of
		586	the current time is a good idea.
		587
		588	See also "The special problem of time updates" in the C<ev_timer> section.
		589
578	=item ev_loop (loop, int flags)	590	=item ev_loop (loop, int flags)
579		591
580	Finally, this is it, the event handler. This function usually is called	592	Finally, this is it, the event handler. This function usually is called
581	after you initialised all your watchers and you want to start handling	593	after you initialised all your watchers and you want to start handling
582	events.	594	events.
…		…
604		616
605	Here are the gory details of what C<ev_loop> does:	617	Here are the gory details of what C<ev_loop> does:
606		618
607	- Before the first iteration, call any pending watchers.	619	- Before the first iteration, call any pending watchers.
608	* If EVFLAG_FORKCHECK was used, check for a fork.	620	* If EVFLAG_FORKCHECK was used, check for a fork.
609	- If a fork was detected, queue and call all fork watchers.	621	- If a fork was detected (by any means), queue and call all fork watchers.
610	- Queue and call all prepare watchers.	622	- Queue and call all prepare watchers.
611	- If we have been forked, recreate the kernel state.	623	- If we have been forked, detach and recreate the kernel state
		624	as to not disturb the other process.
612	- Update the kernel state with all outstanding changes.	625	- Update the kernel state with all outstanding changes.
613	- Update the "event loop time".	626	- Update the "event loop time" (ev_now ()).
614	- Calculate for how long to sleep or block, if at all	627	- Calculate for how long to sleep or block, if at all
615	(active idle watchers, EVLOOP_NONBLOCK or not having	628	(active idle watchers, EVLOOP_NONBLOCK or not having
616	any active watchers at all will result in not sleeping).	629	any active watchers at all will result in not sleeping).
617	- Sleep if the I/O and timer collect interval say so.	630	- Sleep if the I/O and timer collect interval say so.
618	- Block the process, waiting for any events.	631	- Block the process, waiting for any events.
619	- Queue all outstanding I/O (fd) events.	632	- Queue all outstanding I/O (fd) events.
620	- Update the "event loop time" and do time jump handling.	633	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
621	- Queue all outstanding timers.	634	- Queue all outstanding timers.
622	- Queue all outstanding periodics.	635	- Queue all outstanding periodics.
623	- If no events are pending now, queue all idle watchers.	636	- Unless any events are pending now, queue all idle watchers.
624	- Queue all check watchers.	637	- Queue all check watchers.
625	- Call all queued watchers in reverse order (i.e. check watchers first).	638	- Call all queued watchers in reverse order (i.e. check watchers first).
626	Signals and child watchers are implemented as I/O watchers, and will	639	Signals and child watchers are implemented as I/O watchers, and will
627	be handled here by queueing them when their watcher gets executed.	640	be handled here by queueing them when their watcher gets executed.
628	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	641	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
…		…
633	anymore.	646	anymore.
634		647
635	... queue jobs here, make sure they register event watchers as long	648	... queue jobs here, make sure they register event watchers as long
636	... as they still have work to do (even an idle watcher will do..)	649	... as they still have work to do (even an idle watcher will do..)
637	ev_loop (my_loop, 0);	650	ev_loop (my_loop, 0);
638	... jobs done. yeah!	651	... jobs done or somebody called unloop. yeah!
639		652
640	=item ev_unloop (loop, how)	653	=item ev_unloop (loop, how)
641		654
642	Can be used to make a call to C<ev_loop> return early (but only after it	655	Can be used to make a call to C<ev_loop> return early (but only after it
643	has processed all outstanding events). The C<how> argument must be either	656	has processed all outstanding events). The C<how> argument must be either
…		…
664	respectively).	677	respectively).
665		678
666	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	679	Example: Create a signal watcher, but keep it from keeping C<ev_loop>
667	running when nothing else is active.	680	running when nothing else is active.
668		681
669	struct ev_signal exitsig;	682	struct ev_signal exitsig;
670	ev_signal_init (&exitsig, sig_cb, SIGINT);	683	ev_signal_init (&exitsig, sig_cb, SIGINT);
671	ev_signal_start (loop, &exitsig);	684	ev_signal_start (loop, &exitsig);
672	evf_unref (loop);	685	evf_unref (loop);
673		686
674	Example: For some weird reason, unregister the above signal handler again.	687	Example: For some weird reason, unregister the above signal handler again.
675		688
676	ev_ref (loop);	689	ev_ref (loop);
677	ev_signal_stop (loop, &exitsig);	690	ev_signal_stop (loop, &exitsig);
678		691
679	=item ev_set_io_collect_interval (loop, ev_tstamp interval)	692	=item ev_set_io_collect_interval (loop, ev_tstamp interval)
680		693
681	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)	694	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
682		695
683	These advanced functions influence the time that libev will spend waiting	696	These advanced functions influence the time that libev will spend waiting
684	for events. Both are by default C<0>, meaning that libev will try to	697	for events. Both time intervals are by default C<0>, meaning that libev
685	invoke timer/periodic callbacks and I/O callbacks with minimum latency.	698	will try to invoke timer/periodic callbacks and I/O callbacks with minimum
		699	latency.
686		700
687	Setting these to a higher value (the C<interval> I<must> be >= C<0>)	701	Setting these to a higher value (the C<interval> I<must> be >= C<0>)
688	allows libev to delay invocation of I/O and timer/periodic callbacks to	702	allows libev to delay invocation of I/O and timer/periodic callbacks
689	increase efficiency of loop iterations.	703	to increase efficiency of loop iterations (or to increase power-saving
		704	opportunities).
690		705
691	The background is that sometimes your program runs just fast enough to	706	The background is that sometimes your program runs just fast enough to
692	handle one (or very few) event(s) per loop iteration. While this makes	707	handle one (or very few) event(s) per loop iteration. While this makes
693	the program responsive, it also wastes a lot of CPU time to poll for new	708	the program responsive, it also wastes a lot of CPU time to poll for new
694	events, especially with backends like C<select ()> which have a high	709	events, especially with backends like C<select ()> which have a high
…		…
710	interval to a value near C<0.1> or so, which is often enough for	725	interval to a value near C<0.1> or so, which is often enough for
711	interactive servers (of course not for games), likewise for timeouts. It	726	interactive servers (of course not for games), likewise for timeouts. It
712	usually doesn't make much sense to set it to a lower value than C<0.01>,	727	usually doesn't make much sense to set it to a lower value than C<0.01>,
713	as this approaches the timing granularity of most systems.	728	as this approaches the timing granularity of most systems.
714		729
		730	Setting the I<timeout collect interval> can improve the opportunity for
		731	saving power, as the program will "bundle" timer callback invocations that
		732	are "near" in time together, by delaying some, thus reducing the number of
		733	times the process sleeps and wakes up again. Another useful technique to
		734	reduce iterations/wake-ups is to use C<ev_periodic> watchers and make sure
		735	they fire on, say, one-second boundaries only.
		736
715	=item ev_loop_verify (loop)	737	=item ev_loop_verify (loop)
716		738
717	This function only does something when C<EV_VERIFY> support has been	739	This function only does something when C<EV_VERIFY> support has been
718	compiled in. It tries to go through all internal structures and checks	740	compiled in. It tries to go through all internal structures and checks
719	them for validity. If anything is found to be inconsistent, it will print	741	them for validity. If anything is found to be inconsistent, it will print
…		…
730		752
731	A watcher is a structure that you create and register to record your	753	A watcher is a structure that you create and register to record your
732	interest in some event. For instance, if you want to wait for STDIN to	754	interest in some event. For instance, if you want to wait for STDIN to
733	become readable, you would create an C<ev_io> watcher for that:	755	become readable, you would create an C<ev_io> watcher for that:
734		756
735	static void my_cb (struct ev_loop loop, struct ev_io w, int revents)	757	static void my_cb (struct ev_loop loop, struct ev_io w, int revents)
736	{	758	{
737	ev_io_stop (w);	759	ev_io_stop (w);
738	ev_unloop (loop, EVUNLOOP_ALL);	760	ev_unloop (loop, EVUNLOOP_ALL);
739	}	761	}
740		762
741	struct ev_loop *loop = ev_default_loop (0);	763	struct ev_loop *loop = ev_default_loop (0);
742	struct ev_io stdin_watcher;	764	struct ev_io stdin_watcher;
743	ev_init (&stdin_watcher, my_cb);	765	ev_init (&stdin_watcher, my_cb);
744	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	766	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
745	ev_io_start (loop, &stdin_watcher);	767	ev_io_start (loop, &stdin_watcher);
746	ev_loop (loop, 0);	768	ev_loop (loop, 0);
747		769
748	As you can see, you are responsible for allocating the memory for your	770	As you can see, you are responsible for allocating the memory for your
749	watcher structures (and it is usually a bad idea to do this on the stack,	771	watcher structures (and it is usually a bad idea to do this on the stack,
750	although this can sometimes be quite valid).	772	although this can sometimes be quite valid).
751		773
…		…
978	to associate arbitrary data with your watcher. If you need more data and	1000	to associate arbitrary data with your watcher. If you need more data and
979	don't want to allocate memory and store a pointer to it in that data	1001	don't want to allocate memory and store a pointer to it in that data
980	member, you can also "subclass" the watcher type and provide your own	1002	member, you can also "subclass" the watcher type and provide your own
981	data:	1003	data:
982		1004
983	struct my_io	1005	struct my_io
984	{	1006	{
985	struct ev_io io;	1007	struct ev_io io;
986	int otherfd;	1008	int otherfd;
987	void *somedata;	1009	void *somedata;
988	struct whatever *mostinteresting;	1010	struct whatever *mostinteresting;
989	}	1011	}
990		1012
991	And since your callback will be called with a pointer to the watcher, you	1013	And since your callback will be called with a pointer to the watcher, you
992	can cast it back to your own type:	1014	can cast it back to your own type:
993		1015
994	static void my_cb (struct ev_loop loop, struct ev_io w_, int revents)	1016	static void my_cb (struct ev_loop loop, struct ev_io w_, int revents)
995	{	1017	{
996	struct my_io w = (struct my_io )w_;	1018	struct my_io w = (struct my_io )w_;
997	...	1019	...
998	}	1020	}
999		1021
1000	More interesting and less C-conformant ways of casting your callback type	1022	More interesting and less C-conformant ways of casting your callback type
1001	instead have been omitted.	1023	instead have been omitted.
1002		1024
1003	Another common scenario is having some data structure with multiple	1025	Another common scenario is having some data structure with multiple
1004	watchers:	1026	watchers:
1005		1027
1006	struct my_biggy	1028	struct my_biggy
1007	{	1029	{
1008	int some_data;	1030	int some_data;
1009	ev_timer t1;	1031	ev_timer t1;
1010	ev_timer t2;	1032	ev_timer t2;
1011	}	1033	}
1012		1034
1013	In this case getting the pointer to C<my_biggy> is a bit more complicated,	1035	In this case getting the pointer to C<my_biggy> is a bit more complicated,
1014	you need to use C<offsetof>:	1036	you need to use C<offsetof>:
1015		1037
1016	#include <stddef.h>	1038	#include <stddef.h>
1017		1039
1018	static void	1040	static void
1019	t1_cb (EV_P_ struct ev_timer *w, int revents)	1041	t1_cb (EV_P_ struct ev_timer *w, int revents)
1020	{	1042	{
1021	struct my_biggy big = (struct my_biggy *	1043	struct my_biggy big = (struct my_biggy *
1022	(((char *)w) - offsetof (struct my_biggy, t1));	1044	(((char *)w) - offsetof (struct my_biggy, t1));
1023	}	1045	}
1024		1046
1025	static void	1047	static void
1026	t2_cb (EV_P_ struct ev_timer *w, int revents)	1048	t2_cb (EV_P_ struct ev_timer *w, int revents)
1027	{	1049	{
1028	struct my_biggy big = (struct my_biggy *	1050	struct my_biggy big = (struct my_biggy *
1029	(((char *)w) - offsetof (struct my_biggy, t2));	1051	(((char *)w) - offsetof (struct my_biggy, t2));
1030	}	1052	}
1031		1053
1032		1054
1033	=head1 WATCHER TYPES	1055	=head1 WATCHER TYPES
1034		1056
1035	This section describes each watcher in detail, but will not repeat	1057	This section describes each watcher in detail, but will not repeat
…		…
1124	C<EVBACKEND_POLL>.	1146	C<EVBACKEND_POLL>.
1125		1147
1126	=head3 The special problem of SIGPIPE	1148	=head3 The special problem of SIGPIPE
1127		1149
1128	While not really specific to libev, it is easy to forget about SIGPIPE:	1150	While not really specific to libev, it is easy to forget about SIGPIPE:
1129	when reading from a pipe whose other end has been closed, your program	1151	when writing to a pipe whose other end has been closed, your program gets
1130	gets send a SIGPIPE, which, by default, aborts your program. For most	1152	send a SIGPIPE, which, by default, aborts your program. For most programs
1131	programs this is sensible behaviour, for daemons, this is usually	1153	this is sensible behaviour, for daemons, this is usually undesirable.
1132	undesirable.
1133		1154
1134	So when you encounter spurious, unexplained daemon exits, make sure you	1155	So when you encounter spurious, unexplained daemon exits, make sure you
1135	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon	1156	ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
1136	somewhere, as that would have given you a big clue).	1157	somewhere, as that would have given you a big clue).
1137		1158
…		…
1162		1183
1163	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well	1184	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
1164	readable, but only once. Since it is likely line-buffered, you could	1185	readable, but only once. Since it is likely line-buffered, you could
1165	attempt to read a whole line in the callback.	1186	attempt to read a whole line in the callback.
1166		1187
1167	static void	1188	static void
1168	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	1189	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
1169	{	1190	{
1170	ev_io_stop (loop, w);	1191	ev_io_stop (loop, w);
1171	.. read from stdin here (or from w->fd) and haqndle any I/O errors	1192	.. read from stdin here (or from w->fd) and haqndle any I/O errors
1172	}	1193	}
1173		1194
1174	...	1195	...
1175	struct ev_loop *loop = ev_default_init (0);	1196	struct ev_loop *loop = ev_default_init (0);
1176	struct ev_io stdin_readable;	1197	struct ev_io stdin_readable;
1177	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1198	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1178	ev_io_start (loop, &stdin_readable);	1199	ev_io_start (loop, &stdin_readable);
1179	ev_loop (loop, 0);	1200	ev_loop (loop, 0);
1180		1201
1181		1202
1182	=head2 C<ev_timer> - relative and optionally repeating timeouts	1203	=head2 C<ev_timer> - relative and optionally repeating timeouts
1183		1204
1184	Timer watchers are simple relative timers that generate an event after a	1205	Timer watchers are simple relative timers that generate an event after a
…		…
1188	times out after an hour and you reset your system clock to January last	1209	times out after an hour and you reset your system clock to January last
1189	year, it will still time out after (roughly) and hour. "Roughly" because	1210	year, it will still time out after (roughly) and hour. "Roughly" because
1190	detecting time jumps is hard, and some inaccuracies are unavoidable (the	1211	detecting time jumps is hard, and some inaccuracies are unavoidable (the
1191	monotonic clock option helps a lot here).	1212	monotonic clock option helps a lot here).
1192		1213
		1214	The callback is guaranteed to be invoked only after its timeout has passed,
		1215	but if multiple timers become ready during the same loop iteration then
		1216	order of execution is undefined.
		1217
		1218	=head3 The special problem of time updates
		1219
		1220	Establishing the current time is a costly operation (it usually takes at
		1221	least two system calls): EV therefore updates its idea of the current
		1222	time only before and after C<ev_loop> polls for new events, which causes
		1223	a growing difference between C<ev_now ()> and C<ev_time ()> when handling
		1224	lots of events.
		1225
1193	The relative timeouts are calculated relative to the C<ev_now ()>	1226	The relative timeouts are calculated relative to the C<ev_now ()>
1194	time. This is usually the right thing as this timestamp refers to the time	1227	time. This is usually the right thing as this timestamp refers to the time
1195	of the event triggering whatever timeout you are modifying/starting. If	1228	of the event triggering whatever timeout you are modifying/starting. If
1196	you suspect event processing to be delayed and you I<need> to base the timeout	1229	you suspect event processing to be delayed and you I<need> to base the
1197	on the current time, use something like this to adjust for this:	1230	timeout on the current time, use something like this to adjust for this:
1198		1231
1199	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);	1232	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
1200		1233
1201	The callback is guaranteed to be invoked only after its timeout has passed,	1234	If the event loop is suspended for a long time, one can also force an
1202	but if multiple timers become ready during the same loop iteration then	1235	update of the time returned by C<ev_now ()> by calling C<ev_now_update
1203	order of execution is undefined.	1236	()>.
1204		1237
1205	=head3 Watcher-Specific Functions and Data Members	1238	=head3 Watcher-Specific Functions and Data Members
1206		1239
1207	=over 4	1240	=over 4
1208		1241
…		…
1269		1302
1270	=head3 Examples	1303	=head3 Examples
1271		1304
1272	Example: Create a timer that fires after 60 seconds.	1305	Example: Create a timer that fires after 60 seconds.
1273		1306
1274	static void	1307	static void
1275	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1308	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
1276	{	1309	{
1277	.. one minute over, w is actually stopped right here	1310	.. one minute over, w is actually stopped right here
1278	}	1311	}
1279		1312
1280	struct ev_timer mytimer;	1313	struct ev_timer mytimer;
1281	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1314	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1282	ev_timer_start (loop, &mytimer);	1315	ev_timer_start (loop, &mytimer);
1283		1316
1284	Example: Create a timeout timer that times out after 10 seconds of	1317	Example: Create a timeout timer that times out after 10 seconds of
1285	inactivity.	1318	inactivity.
1286		1319
1287	static void	1320	static void
1288	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1321	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
1289	{	1322	{
1290	.. ten seconds without any activity	1323	.. ten seconds without any activity
1291	}	1324	}
1292		1325
1293	struct ev_timer mytimer;	1326	struct ev_timer mytimer;
1294	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	1327	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1295	ev_timer_again (&mytimer); /* start timer */	1328	ev_timer_again (&mytimer); /* start timer */
1296	ev_loop (loop, 0);	1329	ev_loop (loop, 0);
1297		1330
1298	// and in some piece of code that gets executed on any "activity":	1331	// and in some piece of code that gets executed on any "activity":
1299	// reset the timeout to start ticking again at 10 seconds	1332	// reset the timeout to start ticking again at 10 seconds
1300	ev_timer_again (&mytimer);	1333	ev_timer_again (&mytimer);
1301		1334
1302		1335
1303	=head2 C<ev_periodic> - to cron or not to cron?	1336	=head2 C<ev_periodic> - to cron or not to cron?
1304		1337
1305	Periodic watchers are also timers of a kind, but they are very versatile	1338	Periodic watchers are also timers of a kind, but they are very versatile
…		…
1448		1481
1449	Example: Call a callback every hour, or, more precisely, whenever the	1482	Example: Call a callback every hour, or, more precisely, whenever the
1450	system clock is divisible by 3600. The callback invocation times have	1483	system clock is divisible by 3600. The callback invocation times have
1451	potentially a lot of jitter, but good long-term stability.	1484	potentially a lot of jitter, but good long-term stability.
1452		1485
1453	static void	1486	static void
1454	clock_cb (struct ev_loop loop, struct ev_io w, int revents)	1487	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
1455	{	1488	{
1456	... its now a full hour (UTC, or TAI or whatever your clock follows)	1489	... its now a full hour (UTC, or TAI or whatever your clock follows)
1457	}	1490	}
1458		1491
1459	struct ev_periodic hourly_tick;	1492	struct ev_periodic hourly_tick;
1460	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1493	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1461	ev_periodic_start (loop, &hourly_tick);	1494	ev_periodic_start (loop, &hourly_tick);
1462		1495
1463	Example: The same as above, but use a reschedule callback to do it:	1496	Example: The same as above, but use a reschedule callback to do it:
1464		1497
1465	#include <math.h>	1498	#include <math.h>
1466		1499
1467	static ev_tstamp	1500	static ev_tstamp
1468	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1501	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1469	{	1502	{
1470	return fmod (now, 3600.) + 3600.;	1503	return fmod (now, 3600.) + 3600.;
1471	}	1504	}
1472		1505
1473	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1506	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1474		1507
1475	Example: Call a callback every hour, starting now:	1508	Example: Call a callback every hour, starting now:
1476		1509
1477	struct ev_periodic hourly_tick;	1510	struct ev_periodic hourly_tick;
1478	ev_periodic_init (&hourly_tick, clock_cb,	1511	ev_periodic_init (&hourly_tick, clock_cb,
1479	fmod (ev_now (loop), 3600.), 3600., 0);	1512	fmod (ev_now (loop), 3600.), 3600., 0);
1480	ev_periodic_start (loop, &hourly_tick);	1513	ev_periodic_start (loop, &hourly_tick);
1481		1514
1482		1515
1483	=head2 C<ev_signal> - signal me when a signal gets signalled!	1516	=head2 C<ev_signal> - signal me when a signal gets signalled!
1484		1517
1485	Signal watchers will trigger an event when the process receives a specific	1518	Signal watchers will trigger an event when the process receives a specific
…		…
1519		1552
1520	=head3 Examples	1553	=head3 Examples
1521		1554
1522	Example: Try to exit cleanly on SIGINT and SIGTERM.	1555	Example: Try to exit cleanly on SIGINT and SIGTERM.
1523		1556
1524	static void	1557	static void
1525	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1558	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1526	{	1559	{
1527	ev_unloop (loop, EVUNLOOP_ALL);	1560	ev_unloop (loop, EVUNLOOP_ALL);
1528	}	1561	}
1529		1562
1530	struct ev_signal signal_watcher;	1563	struct ev_signal signal_watcher;
1531	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1564	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1532	ev_signal_start (loop, &sigint_cb);	1565	ev_signal_start (loop, &sigint_cb);
1533		1566
1534		1567
1535	=head2 C<ev_child> - watch out for process status changes	1568	=head2 C<ev_child> - watch out for process status changes
1536		1569
1537	Child watchers trigger when your process receives a SIGCHLD in response to	1570	Child watchers trigger when your process receives a SIGCHLD in response to
…		…
1559	handler, you can override it easily by installing your own handler for	1592	handler, you can override it easily by installing your own handler for
1560	C<SIGCHLD> after initialising the default loop, and making sure the	1593	C<SIGCHLD> after initialising the default loop, and making sure the
1561	default loop never gets destroyed. You are encouraged, however, to use an	1594	default loop never gets destroyed. You are encouraged, however, to use an
1562	event-based approach to child reaping and thus use libev's support for	1595	event-based approach to child reaping and thus use libev's support for
1563	that, so other libev users can use C<ev_child> watchers freely.	1596	that, so other libev users can use C<ev_child> watchers freely.
		1597
		1598	=head3 Stopping the Child Watcher
		1599
		1600	Currently, the child watcher never gets stopped, even when the
		1601	child terminates, so normally one needs to stop the watcher in the
		1602	callback. Future versions of libev might stop the watcher automatically
		1603	when a child exit is detected.
1564		1604
1565	=head3 Watcher-Specific Functions and Data Members	1605	=head3 Watcher-Specific Functions and Data Members
1566		1606
1567	=over 4	1607	=over 4
1568		1608
…		…
1597	=head3 Examples	1637	=head3 Examples
1598		1638
1599	Example: C<fork()> a new process and install a child handler to wait for	1639	Example: C<fork()> a new process and install a child handler to wait for
1600	its completion.	1640	its completion.
1601		1641
1602	ev_child cw;	1642	ev_child cw;
1603		1643
1604	static void	1644	static void
1605	child_cb (EV_P_ struct ev_child *w, int revents)	1645	child_cb (EV_P_ struct ev_child *w, int revents)
1606	{	1646	{
1607	ev_child_stop (EV_A_ w);	1647	ev_child_stop (EV_A_ w);
1608	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);	1648	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
1609	}	1649	}
1610		1650
1611	pid_t pid = fork ();	1651	pid_t pid = fork ();
1612		1652
1613	if (pid < 0)	1653	if (pid < 0)
1614	// error	1654	// error
1615	else if (pid == 0)	1655	else if (pid == 0)
1616	{	1656	{
1617	// the forked child executes here	1657	// the forked child executes here
1618	exit (1);	1658	exit (1);
1619	}	1659	}
1620	else	1660	else
1621	{	1661	{
1622	ev_child_init (&cw, child_cb, pid, 0);	1662	ev_child_init (&cw, child_cb, pid, 0);
1623	ev_child_start (EV_DEFAULT_ &cw);	1663	ev_child_start (EV_DEFAULT_ &cw);
1624	}	1664	}
1625		1665
1626		1666
1627	=head2 C<ev_stat> - did the file attributes just change?	1667	=head2 C<ev_stat> - did the file attributes just change?
1628		1668
1629	This watches a file system path for attribute changes. That is, it calls	1669	This watches a file system path for attribute changes. That is, it calls
…		…
1662	will be no polling.	1702	will be no polling.
1663		1703
1664	=head3 ABI Issues (Largefile Support)	1704	=head3 ABI Issues (Largefile Support)
1665		1705
1666	Libev by default (unless the user overrides this) uses the default	1706	Libev by default (unless the user overrides this) uses the default
1667	compilation environment, which means that on systems with optionally	1707	compilation environment, which means that on systems with large file
1668	disabled large file support, you get the 32 bit version of the stat	1708	support disabled by default, you get the 32 bit version of the stat
1669	structure. When using the library from programs that change the ABI to	1709	structure. When using the library from programs that change the ABI to
1670	use 64 bit file offsets the programs will fail. In that case you have to	1710	use 64 bit file offsets the programs will fail. In that case you have to
1671	compile libev with the same flags to get binary compatibility. This is	1711	compile libev with the same flags to get binary compatibility. This is
1672	obviously the case with any flags that change the ABI, but the problem is	1712	obviously the case with any flags that change the ABI, but the problem is
1673	most noticeably with ev_stat and large file support.	1713	most noticeably disabled with ev_stat and large file support.
		1714
		1715	The solution for this is to lobby your distribution maker to make large
		1716	file interfaces available by default (as e.g. FreeBSD does) and not
		1717	optional. Libev cannot simply switch on large file support because it has
		1718	to exchange stat structures with application programs compiled using the
		1719	default compilation environment.
1674		1720
1675	=head3 Inotify	1721	=head3 Inotify
1676		1722
1677	When C<inotify (7)> support has been compiled into libev (generally only	1723	When C<inotify (7)> support has been compiled into libev (generally only
1678	available on Linux) and present at runtime, it will be used to speed up	1724	available on Linux) and present at runtime, it will be used to speed up
…		…
1767		1813
1768	=head3 Examples	1814	=head3 Examples
1769		1815
1770	Example: Watch C</etc/passwd> for attribute changes.	1816	Example: Watch C</etc/passwd> for attribute changes.
1771		1817
1772	static void	1818	static void
1773	passwd_cb (struct ev_loop loop, ev_stat w, int revents)	1819	passwd_cb (struct ev_loop loop, ev_stat w, int revents)
1774	{	1820	{
1775	/* /etc/passwd changed in some way */	1821	/* /etc/passwd changed in some way */
1776	if (w->attr.st_nlink)	1822	if (w->attr.st_nlink)
1777	{	1823	{
1778	printf ("passwd current size %ld\n", (long)w->attr.st_size);	1824	printf ("passwd current size %ld\n", (long)w->attr.st_size);
1779	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);	1825	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
1780	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);	1826	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
1781	}	1827	}
1782	else	1828	else
1783	/* you shalt not abuse printf for puts */	1829	/* you shalt not abuse printf for puts */
1784	puts ("wow, /etc/passwd is not there, expect problems. "	1830	puts ("wow, /etc/passwd is not there, expect problems. "
1785	"if this is windows, they already arrived\n");	1831	"if this is windows, they already arrived\n");
1786	}	1832	}
1787		1833
1788	...	1834	...
1789	ev_stat passwd;	1835	ev_stat passwd;
1790		1836
1791	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);	1837	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
1792	ev_stat_start (loop, &passwd);	1838	ev_stat_start (loop, &passwd);
1793		1839
1794	Example: Like above, but additionally use a one-second delay so we do not	1840	Example: Like above, but additionally use a one-second delay so we do not
1795	miss updates (however, frequent updates will delay processing, too, so	1841	miss updates (however, frequent updates will delay processing, too, so
1796	one might do the work both on C<ev_stat> callback invocation I<and> on	1842	one might do the work both on C<ev_stat> callback invocation I<and> on
1797	C<ev_timer> callback invocation).	1843	C<ev_timer> callback invocation).
1798		1844
1799	static ev_stat passwd;	1845	static ev_stat passwd;
1800	static ev_timer timer;	1846	static ev_timer timer;
1801		1847
1802	static void	1848	static void
1803	timer_cb (EV_P_ ev_timer *w, int revents)	1849	timer_cb (EV_P_ ev_timer *w, int revents)
1804	{	1850	{
1805	ev_timer_stop (EV_A_ w);	1851	ev_timer_stop (EV_A_ w);
1806		1852
1807	/* now it's one second after the most recent passwd change */	1853	/* now it's one second after the most recent passwd change */
1808	}	1854	}
1809		1855
1810	static void	1856	static void
1811	stat_cb (EV_P_ ev_stat *w, int revents)	1857	stat_cb (EV_P_ ev_stat *w, int revents)
1812	{	1858	{
1813	/* reset the one-second timer */	1859	/* reset the one-second timer */
1814	ev_timer_again (EV_A_ &timer);	1860	ev_timer_again (EV_A_ &timer);
1815	}	1861	}
1816		1862
1817	...	1863	...
1818	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);	1864	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
1819	ev_stat_start (loop, &passwd);	1865	ev_stat_start (loop, &passwd);
1820	ev_timer_init (&timer, timer_cb, 0., 1.02);	1866	ev_timer_init (&timer, timer_cb, 0., 1.02);
1821		1867
1822		1868
1823	=head2 C<ev_idle> - when you've got nothing better to do...	1869	=head2 C<ev_idle> - when you've got nothing better to do...
1824		1870
1825	Idle watchers trigger events when no other events of the same or higher	1871	Idle watchers trigger events when no other events of the same or higher
…		…
1856	=head3 Examples	1902	=head3 Examples
1857		1903
1858	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the	1904	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1859	callback, free it. Also, use no error checking, as usual.	1905	callback, free it. Also, use no error checking, as usual.
1860		1906
1861	static void	1907	static void
1862	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1908	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1863	{	1909	{
1864	free (w);	1910	free (w);
1865	// now do something you wanted to do when the program has	1911	// now do something you wanted to do when the program has
1866	// no longer anything immediate to do.	1912	// no longer anything immediate to do.
1867	}	1913	}
1868		1914
1869	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1915	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1870	ev_idle_init (idle_watcher, idle_cb);	1916	ev_idle_init (idle_watcher, idle_cb);
1871	ev_idle_start (loop, idle_cb);	1917	ev_idle_start (loop, idle_cb);
1872		1918
1873		1919
1874	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!	1920	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
1875		1921
1876	Prepare and check watchers are usually (but not always) used in tandem:	1922	Prepare and check watchers are usually (but not always) used in tandem:
…		…
1948	and in a check watcher, destroy them and call into libadns. What follows	1994	and in a check watcher, destroy them and call into libadns. What follows
1949	is pseudo-code only of course. This requires you to either use a low	1995	is pseudo-code only of course. This requires you to either use a low
1950	priority for the check watcher or use C<ev_clear_pending> explicitly, as	1996	priority for the check watcher or use C<ev_clear_pending> explicitly, as
1951	the callbacks for the IO/timeout watchers might not have been called yet.	1997	the callbacks for the IO/timeout watchers might not have been called yet.
1952		1998
1953	static ev_io iow [nfd];	1999	static ev_io iow [nfd];
1954	static ev_timer tw;	2000	static ev_timer tw;
1955		2001
1956	static void	2002	static void
1957	io_cb (ev_loop loop, ev_io w, int revents)	2003	io_cb (ev_loop loop, ev_io w, int revents)
1958	{	2004	{
1959	}	2005	}
1960		2006
1961	// create io watchers for each fd and a timer before blocking	2007	// create io watchers for each fd and a timer before blocking
1962	static void	2008	static void
1963	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	2009	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1964	{	2010	{
1965	int timeout = 3600000;	2011	int timeout = 3600000;
1966	struct pollfd fds [nfd];	2012	struct pollfd fds [nfd];
1967	// actual code will need to loop here and realloc etc.	2013	// actual code will need to loop here and realloc etc.
1968	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	2014	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1969		2015
1970	/* the callback is illegal, but won't be called as we stop during check */	2016	/* the callback is illegal, but won't be called as we stop during check */
1971	ev_timer_init (&tw, 0, timeout * 1e-3);	2017	ev_timer_init (&tw, 0, timeout * 1e-3);
1972	ev_timer_start (loop, &tw);	2018	ev_timer_start (loop, &tw);
1973		2019
1974	// create one ev_io per pollfd	2020	// create one ev_io per pollfd
1975	for (int i = 0; i < nfd; ++i)	2021	for (int i = 0; i < nfd; ++i)
1976	{	2022	{
1977	ev_io_init (iow + i, io_cb, fds [i].fd,	2023	ev_io_init (iow + i, io_cb, fds [i].fd,
1978	((fds [i].events & POLLIN ? EV_READ : 0)	2024	((fds [i].events & POLLIN ? EV_READ : 0)
1979	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	2025	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1980		2026
1981	fds [i].revents = 0;	2027	fds [i].revents = 0;
1982	ev_io_start (loop, iow + i);	2028	ev_io_start (loop, iow + i);
1983	}	2029	}
1984	}	2030	}
1985		2031
1986	// stop all watchers after blocking	2032	// stop all watchers after blocking
1987	static void	2033	static void
1988	adns_check_cb (ev_loop loop, ev_check w, int revents)	2034	adns_check_cb (ev_loop loop, ev_check w, int revents)
1989	{	2035	{
1990	ev_timer_stop (loop, &tw);	2036	ev_timer_stop (loop, &tw);
1991		2037
1992	for (int i = 0; i < nfd; ++i)	2038	for (int i = 0; i < nfd; ++i)
1993	{	2039	{
1994	// set the relevant poll flags	2040	// set the relevant poll flags
1995	// could also call adns_processreadable etc. here	2041	// could also call adns_processreadable etc. here
1996	struct pollfd *fd = fds + i;	2042	struct pollfd *fd = fds + i;
1997	int revents = ev_clear_pending (iow + i);	2043	int revents = ev_clear_pending (iow + i);
1998	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;	2044	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1999	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;	2045	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
2000		2046
2001	// now stop the watcher	2047	// now stop the watcher
2002	ev_io_stop (loop, iow + i);	2048	ev_io_stop (loop, iow + i);
2003	}	2049	}
2004		2050
2005	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	2051	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
2006	}	2052	}
2007		2053
2008	Method 2: This would be just like method 1, but you run C<adns_afterpoll>	2054	Method 2: This would be just like method 1, but you run C<adns_afterpoll>
2009	in the prepare watcher and would dispose of the check watcher.	2055	in the prepare watcher and would dispose of the check watcher.
2010		2056
2011	Method 3: If the module to be embedded supports explicit event	2057	Method 3: If the module to be embedded supports explicit event
2012	notification (libadns does), you can also make use of the actual watcher	2058	notification (libadns does), you can also make use of the actual watcher
2013	callbacks, and only destroy/create the watchers in the prepare watcher.	2059	callbacks, and only destroy/create the watchers in the prepare watcher.
2014		2060
2015	static void	2061	static void
2016	timer_cb (EV_P_ ev_timer *w, int revents)	2062	timer_cb (EV_P_ ev_timer *w, int revents)
2017	{	2063	{
2018	adns_state ads = (adns_state)w->data;	2064	adns_state ads = (adns_state)w->data;
2019	update_now (EV_A);	2065	update_now (EV_A);
2020		2066
2021	adns_processtimeouts (ads, &tv_now);	2067	adns_processtimeouts (ads, &tv_now);
2022	}	2068	}
2023		2069
2024	static void	2070	static void
2025	io_cb (EV_P_ ev_io *w, int revents)	2071	io_cb (EV_P_ ev_io *w, int revents)
2026	{	2072	{
2027	adns_state ads = (adns_state)w->data;	2073	adns_state ads = (adns_state)w->data;
2028	update_now (EV_A);	2074	update_now (EV_A);
2029		2075
2030	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);	2076	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
2031	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);	2077	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
2032	}	2078	}
2033		2079
2034	// do not ever call adns_afterpoll	2080	// do not ever call adns_afterpoll
2035		2081
2036	Method 4: Do not use a prepare or check watcher because the module you	2082	Method 4: Do not use a prepare or check watcher because the module you
2037	want to embed is too inflexible to support it. Instead, you can override	2083	want to embed is too inflexible to support it. Instead, you can override
2038	their poll function. The drawback with this solution is that the main	2084	their poll function. The drawback with this solution is that the main
2039	loop is now no longer controllable by EV. The C<Glib::EV> module does	2085	loop is now no longer controllable by EV. The C<Glib::EV> module does
2040	this.	2086	this.
2041		2087
2042	static gint	2088	static gint
2043	event_poll_func (GPollFD *fds, guint nfds, gint timeout)	2089	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
2044	{	2090	{
2045	int got_events = 0;	2091	int got_events = 0;
2046		2092
2047	for (n = 0; n < nfds; ++n)	2093	for (n = 0; n < nfds; ++n)
2048	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events	2094	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
2049		2095
2050	if (timeout >= 0)	2096	if (timeout >= 0)
2051	// create/start timer	2097	// create/start timer
2052		2098
2053	// poll	2099	// poll
2054	ev_loop (EV_A_ 0);	2100	ev_loop (EV_A_ 0);
2055		2101
2056	// stop timer again	2102	// stop timer again
2057	if (timeout >= 0)	2103	if (timeout >= 0)
2058	ev_timer_stop (EV_A_ &to);	2104	ev_timer_stop (EV_A_ &to);
2059		2105
2060	// stop io watchers again - their callbacks should have set	2106	// stop io watchers again - their callbacks should have set
2061	for (n = 0; n < nfds; ++n)	2107	for (n = 0; n < nfds; ++n)
2062	ev_io_stop (EV_A_ iow [n]);	2108	ev_io_stop (EV_A_ iow [n]);
2063		2109
2064	return got_events;	2110	return got_events;
2065	}	2111	}
2066		2112
2067		2113
2068	=head2 C<ev_embed> - when one backend isn't enough...	2114	=head2 C<ev_embed> - when one backend isn't enough...
2069		2115
2070	This is a rather advanced watcher type that lets you embed one event loop	2116	This is a rather advanced watcher type that lets you embed one event loop
…		…
2148	event loop. If that is not possible, use the default loop. The default	2194	event loop. If that is not possible, use the default loop. The default
2149	loop is stored in C<loop_hi>, while the embeddable loop is stored in	2195	loop is stored in C<loop_hi>, while the embeddable loop is stored in
2150	C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be	2196	C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
2151	used).	2197	used).
2152		2198
2153	struct ev_loop *loop_hi = ev_default_init (0);	2199	struct ev_loop *loop_hi = ev_default_init (0);
2154	struct ev_loop *loop_lo = 0;	2200	struct ev_loop *loop_lo = 0;
2155	struct ev_embed embed;	2201	struct ev_embed embed;
2156		2202
2157	// see if there is a chance of getting one that works	2203	// see if there is a chance of getting one that works
2158	// (remember that a flags value of 0 means autodetection)	2204	// (remember that a flags value of 0 means autodetection)
2159	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()	2205	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
2160	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())	2206	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
2161	: 0;	2207	: 0;
2162		2208
2163	// if we got one, then embed it, otherwise default to loop_hi	2209	// if we got one, then embed it, otherwise default to loop_hi
2164	if (loop_lo)	2210	if (loop_lo)
2165	{	2211	{
2166	ev_embed_init (&embed, 0, loop_lo);	2212	ev_embed_init (&embed, 0, loop_lo);
2167	ev_embed_start (loop_hi, &embed);	2213	ev_embed_start (loop_hi, &embed);
2168	}	2214	}
2169	else	2215	else
2170	loop_lo = loop_hi;	2216	loop_lo = loop_hi;
2171		2217
2172	Example: Check if kqueue is available but not recommended and create	2218	Example: Check if kqueue is available but not recommended and create
2173	a kqueue backend for use with sockets (which usually work with any	2219	a kqueue backend for use with sockets (which usually work with any
2174	kqueue implementation). Store the kqueue/socket-only event loop in	2220	kqueue implementation). Store the kqueue/socket-only event loop in
2175	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).	2221	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
2176		2222
2177	struct ev_loop *loop = ev_default_init (0);	2223	struct ev_loop *loop = ev_default_init (0);
2178	struct ev_loop *loop_socket = 0;	2224	struct ev_loop *loop_socket = 0;
2179	struct ev_embed embed;	2225	struct ev_embed embed;
2180		2226
2181	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)	2227	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
2182	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))	2228	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
2183	{	2229	{
2184	ev_embed_init (&embed, 0, loop_socket);	2230	ev_embed_init (&embed, 0, loop_socket);
2185	ev_embed_start (loop, &embed);	2231	ev_embed_start (loop, &embed);
2186	}	2232	}
2187		2233
2188	if (!loop_socket)	2234	if (!loop_socket)
2189	loop_socket = loop;	2235	loop_socket = loop;
2190		2236
2191	// now use loop_socket for all sockets, and loop for everything else	2237	// now use loop_socket for all sockets, and loop for everything else
2192		2238
2193		2239
2194	=head2 C<ev_fork> - the audacity to resume the event loop after a fork	2240	=head2 C<ev_fork> - the audacity to resume the event loop after a fork
2195		2241
2196	Fork watchers are called when a C<fork ()> was detected (usually because	2242	Fork watchers are called when a C<fork ()> was detected (usually because
…		…
2385	The callback has the type C<void (cb)(int revents, void arg)> and gets	2431	The callback has the type C<void (cb)(int revents, void arg)> and gets
2386	passed an C<revents> set like normal event callbacks (a combination of	2432	passed an C<revents> set like normal event callbacks (a combination of
2387	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	2433	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
2388	value passed to C<ev_once>:	2434	value passed to C<ev_once>:
2389		2435
2390	static void stdin_ready (int revents, void *arg)	2436	static void stdin_ready (int revents, void *arg)
2391	{	2437	{
2392	if (revents & EV_TIMEOUT)	2438	if (revents & EV_TIMEOUT)
2393	/* doh, nothing entered */;	2439	/* doh, nothing entered */;
2394	else if (revents & EV_READ)	2440	else if (revents & EV_READ)
2395	/* stdin might have data for us, joy! */;	2441	/* stdin might have data for us, joy! */;
2396	}	2442	}
2397		2443
2398	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2444	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2399		2445
2400	=item ev_feed_event (ev_loop , watcher , int revents)	2446	=item ev_feed_event (ev_loop , watcher , int revents)
2401		2447
2402	Feeds the given event set into the event loop, as if the specified event	2448	Feeds the given event set into the event loop, as if the specified event
2403	had happened for the specified watcher (which must be a pointer to an	2449	had happened for the specified watcher (which must be a pointer to an
…		…
2452	you to use some convenience methods to start/stop watchers and also change	2498	you to use some convenience methods to start/stop watchers and also change
2453	the callback model to a model using method callbacks on objects.	2499	the callback model to a model using method callbacks on objects.
2454		2500
2455	To use it,	2501	To use it,
2456		2502
2457	#include <ev++.h>	2503	#include <ev++.h>
2458		2504
2459	This automatically includes F<ev.h> and puts all of its definitions (many	2505	This automatically includes F<ev.h> and puts all of its definitions (many
2460	of them macros) into the global namespace. All C++ specific things are	2506	of them macros) into the global namespace. All C++ specific things are
2461	put into the C<ev> namespace. It should support all the same embedding	2507	put into the C<ev> namespace. It should support all the same embedding
2462	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.	2508	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
…		…
2529	your compiler is good :), then the method will be fully inlined into the	2575	your compiler is good :), then the method will be fully inlined into the
2530	thunking function, making it as fast as a direct C callback.	2576	thunking function, making it as fast as a direct C callback.
2531		2577
2532	Example: simple class declaration and watcher initialisation	2578	Example: simple class declaration and watcher initialisation
2533		2579
2534	struct myclass	2580	struct myclass
2535	{	2581	{
2536	void io_cb (ev::io &w, int revents) { }	2582	void io_cb (ev::io &w, int revents) { }
2537	}	2583	}
2538		2584
2539	myclass obj;	2585	myclass obj;
2540	ev::io iow;	2586	ev::io iow;
2541	iow.set <myclass, &myclass::io_cb> (&obj);	2587	iow.set <myclass, &myclass::io_cb> (&obj);
2542		2588
2543	=item w->set<function> (void *data = 0)	2589	=item w->set<function> (void *data = 0)
2544		2590
2545	Also sets a callback, but uses a static method or plain function as	2591	Also sets a callback, but uses a static method or plain function as
2546	callback. The optional C<data> argument will be stored in the watcher's	2592	callback. The optional C<data> argument will be stored in the watcher's
…		…
2550		2596
2551	See the method-C<set> above for more details.	2597	See the method-C<set> above for more details.
2552		2598
2553	Example:	2599	Example:
2554		2600
2555	static void io_cb (ev::io &w, int revents) { }	2601	static void io_cb (ev::io &w, int revents) { }
2556	iow.set <io_cb> ();	2602	iow.set <io_cb> ();
2557		2603
2558	=item w->set (struct ev_loop *)	2604	=item w->set (struct ev_loop *)
2559		2605
2560	Associates a different C<struct ev_loop> with this watcher. You can only	2606	Associates a different C<struct ev_loop> with this watcher. You can only
2561	do this when the watcher is inactive (and not pending either).	2607	do this when the watcher is inactive (and not pending either).
…		…
2594	=back	2640	=back
2595		2641
2596	Example: Define a class with an IO and idle watcher, start one of them in	2642	Example: Define a class with an IO and idle watcher, start one of them in
2597	the constructor.	2643	the constructor.
2598		2644
2599	class myclass	2645	class myclass
2600	{	2646	{
2601	ev::io io; void io_cb (ev::io &w, int revents);	2647	ev::io io; void io_cb (ev::io &w, int revents);
2602	ev:idle idle void idle_cb (ev::idle &w, int revents);	2648	ev:idle idle void idle_cb (ev::idle &w, int revents);
2603		2649
2604	myclass (int fd)	2650	myclass (int fd)
2605	{	2651	{
2606	io .set <myclass, &myclass::io_cb > (this);	2652	io .set <myclass, &myclass::io_cb > (this);
2607	idle.set <myclass, &myclass::idle_cb> (this);	2653	idle.set <myclass, &myclass::idle_cb> (this);
2608		2654
2609	io.start (fd, ev::READ);	2655	io.start (fd, ev::READ);
2610	}	2656	}
2611	};	2657	};
2612		2658
2613		2659
2614	=head1 OTHER LANGUAGE BINDINGS	2660	=head1 OTHER LANGUAGE BINDINGS
2615		2661
2616	Libev does not offer other language bindings itself, but bindings for a	2662	Libev does not offer other language bindings itself, but bindings for a
…		…
2626	libev. EV is developed together with libev. Apart from the EV core module,	2672	libev. EV is developed together with libev. Apart from the EV core module,
2627	there are additional modules that implement libev-compatible interfaces	2673	there are additional modules that implement libev-compatible interfaces
2628	to C<libadns> (C<EV::ADNS>), C<Net::SNMP> (C<Net::SNMP::EV>) and the	2674	to C<libadns> (C<EV::ADNS>), C<Net::SNMP> (C<Net::SNMP::EV>) and the
2629	C<libglib> event core (C<Glib::EV> and C<EV::Glib>).	2675	C<libglib> event core (C<Glib::EV> and C<EV::Glib>).
2630		2676
2631	It can be found and installed via CPAN, its homepage is found at	2677	It can be found and installed via CPAN, its homepage is at
2632	L<http://software.schmorp.de/pkg/EV>.	2678	L<http://software.schmorp.de/pkg/EV>.
		2679
		2680	=item Python
		2681
		2682	Python bindings can be found at L<http://code.google.com/p/pyev/>. It
		2683	seems to be quite complete and well-documented. Note, however, that the
		2684	patch they require for libev is outright dangerous as it breaks the ABI
		2685	for everybody else, and therefore, should never be applied in an installed
		2686	libev (if python requires an incompatible ABI then it needs to embed
		2687	libev).
2633		2688
2634	=item Ruby	2689	=item Ruby
2635		2690
2636	Tony Arcieri has written a ruby extension that offers access to a subset	2691	Tony Arcieri has written a ruby extension that offers access to a subset
2637	of the libev API and adds file handle abstractions, asynchronous DNS and	2692	of the libev API and adds file handle abstractions, asynchronous DNS and
…		…
2639	L<http://rev.rubyforge.org/>.	2694	L<http://rev.rubyforge.org/>.
2640		2695
2641	=item D	2696	=item D
2642		2697
2643	Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to	2698	Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to
2644	be found at L<http://git.llucax.com.ar/?p=software/ev.d.git;a=summary>.	2699	be found at L<http://proj.llucax.com.ar/wiki/evd>.
2645		2700
2646	=back	2701	=back
2647		2702
2648		2703
2649	=head1 MACRO MAGIC	2704	=head1 MACRO MAGIC
…		…
2661		2716
2662	This provides the loop I<argument> for functions, if one is required ("ev	2717	This provides the loop I<argument> for functions, if one is required ("ev
2663	loop argument"). The C<EV_A> form is used when this is the sole argument,	2718	loop argument"). The C<EV_A> form is used when this is the sole argument,
2664	C<EV_A_> is used when other arguments are following. Example:	2719	C<EV_A_> is used when other arguments are following. Example:
2665		2720
2666	ev_unref (EV_A);	2721	ev_unref (EV_A);
2667	ev_timer_add (EV_A_ watcher);	2722	ev_timer_add (EV_A_ watcher);
2668	ev_loop (EV_A_ 0);	2723	ev_loop (EV_A_ 0);
2669		2724
2670	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	2725	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
2671	which is often provided by the following macro.	2726	which is often provided by the following macro.
2672		2727
2673	=item C<EV_P>, C<EV_P_>	2728	=item C<EV_P>, C<EV_P_>
2674		2729
2675	This provides the loop I<parameter> for functions, if one is required ("ev	2730	This provides the loop I<parameter> for functions, if one is required ("ev
2676	loop parameter"). The C<EV_P> form is used when this is the sole parameter,	2731	loop parameter"). The C<EV_P> form is used when this is the sole parameter,
2677	C<EV_P_> is used when other parameters are following. Example:	2732	C<EV_P_> is used when other parameters are following. Example:
2678		2733
2679	// this is how ev_unref is being declared	2734	// this is how ev_unref is being declared
2680	static void ev_unref (EV_P);	2735	static void ev_unref (EV_P);
2681		2736
2682	// this is how you can declare your typical callback	2737	// this is how you can declare your typical callback
2683	static void cb (EV_P_ ev_timer *w, int revents)	2738	static void cb (EV_P_ ev_timer *w, int revents)
2684		2739
2685	It declares a parameter C<loop> of type C<struct ev_loop *>, quite	2740	It declares a parameter C<loop> of type C<struct ev_loop *>, quite
2686	suitable for use with C<EV_A>.	2741	suitable for use with C<EV_A>.
2687		2742
2688	=item C<EV_DEFAULT>, C<EV_DEFAULT_>	2743	=item C<EV_DEFAULT>, C<EV_DEFAULT_>
…		…
2704		2759
2705	Example: Declare and initialise a check watcher, utilising the above	2760	Example: Declare and initialise a check watcher, utilising the above
2706	macros so it will work regardless of whether multiple loops are supported	2761	macros so it will work regardless of whether multiple loops are supported
2707	or not.	2762	or not.
2708		2763
2709	static void	2764	static void
2710	check_cb (EV_P_ ev_timer *w, int revents)	2765	check_cb (EV_P_ ev_timer *w, int revents)
2711	{	2766	{
2712	ev_check_stop (EV_A_ w);	2767	ev_check_stop (EV_A_ w);
2713	}	2768	}
2714		2769
2715	ev_check check;	2770	ev_check check;
2716	ev_check_init (&check, check_cb);	2771	ev_check_init (&check, check_cb);
2717	ev_check_start (EV_DEFAULT_ &check);	2772	ev_check_start (EV_DEFAULT_ &check);
2718	ev_loop (EV_DEFAULT_ 0);	2773	ev_loop (EV_DEFAULT_ 0);
2719		2774
2720	=head1 EMBEDDING	2775	=head1 EMBEDDING
2721		2776
2722	Libev can (and often is) directly embedded into host	2777	Libev can (and often is) directly embedded into host
2723	applications. Examples of applications that embed it include the Deliantra	2778	applications. Examples of applications that embed it include the Deliantra
…		…
2737	=head3 CORE EVENT LOOP	2792	=head3 CORE EVENT LOOP
2738		2793
2739	To include only the libev core (all the C<ev_*> functions), with manual	2794	To include only the libev core (all the C<ev_*> functions), with manual
2740	configuration (no autoconf):	2795	configuration (no autoconf):
2741		2796
2742	#define EV_STANDALONE 1	2797	#define EV_STANDALONE 1
2743	#include "ev.c"	2798	#include "ev.c"
2744		2799
2745	This will automatically include F<ev.h>, too, and should be done in a	2800	This will automatically include F<ev.h>, too, and should be done in a
2746	single C source file only to provide the function implementations. To use	2801	single C source file only to provide the function implementations. To use
2747	it, do the same for F<ev.h> in all files wishing to use this API (best	2802	it, do the same for F<ev.h> in all files wishing to use this API (best
2748	done by writing a wrapper around F<ev.h> that you can include instead and	2803	done by writing a wrapper around F<ev.h> that you can include instead and
2749	where you can put other configuration options):	2804	where you can put other configuration options):
2750		2805
2751	#define EV_STANDALONE 1	2806	#define EV_STANDALONE 1
2752	#include "ev.h"	2807	#include "ev.h"
2753		2808
2754	Both header files and implementation files can be compiled with a C++	2809	Both header files and implementation files can be compiled with a C++
2755	compiler (at least, thats a stated goal, and breakage will be treated	2810	compiler (at least, thats a stated goal, and breakage will be treated
2756	as a bug).	2811	as a bug).
2757		2812
2758	You need the following files in your source tree, or in a directory	2813	You need the following files in your source tree, or in a directory
2759	in your include path (e.g. in libev/ when using -Ilibev):	2814	in your include path (e.g. in libev/ when using -Ilibev):
2760		2815
2761	ev.h	2816	ev.h
2762	ev.c	2817	ev.c
2763	ev_vars.h	2818	ev_vars.h
2764	ev_wrap.h	2819	ev_wrap.h
2765		2820
2766	ev_win32.c required on win32 platforms only	2821	ev_win32.c required on win32 platforms only
2767		2822
2768	ev_select.c only when select backend is enabled (which is enabled by default)	2823	ev_select.c only when select backend is enabled (which is enabled by default)
2769	ev_poll.c only when poll backend is enabled (disabled by default)	2824	ev_poll.c only when poll backend is enabled (disabled by default)
2770	ev_epoll.c only when the epoll backend is enabled (disabled by default)	2825	ev_epoll.c only when the epoll backend is enabled (disabled by default)
2771	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	2826	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
2772	ev_port.c only when the solaris port backend is enabled (disabled by default)	2827	ev_port.c only when the solaris port backend is enabled (disabled by default)
2773		2828
2774	F<ev.c> includes the backend files directly when enabled, so you only need	2829	F<ev.c> includes the backend files directly when enabled, so you only need
2775	to compile this single file.	2830	to compile this single file.
2776		2831
2777	=head3 LIBEVENT COMPATIBILITY API	2832	=head3 LIBEVENT COMPATIBILITY API
2778		2833
2779	To include the libevent compatibility API, also include:	2834	To include the libevent compatibility API, also include:
2780		2835
2781	#include "event.c"	2836	#include "event.c"
2782		2837
2783	in the file including F<ev.c>, and:	2838	in the file including F<ev.c>, and:
2784		2839
2785	#include "event.h"	2840	#include "event.h"
2786		2841
2787	in the files that want to use the libevent API. This also includes F<ev.h>.	2842	in the files that want to use the libevent API. This also includes F<ev.h>.
2788		2843
2789	You need the following additional files for this:	2844	You need the following additional files for this:
2790		2845
2791	event.h	2846	event.h
2792	event.c	2847	event.c
2793		2848
2794	=head3 AUTOCONF SUPPORT	2849	=head3 AUTOCONF SUPPORT
2795		2850
2796	Instead of using C<EV_STANDALONE=1> and providing your configuration in	2851	Instead of using C<EV_STANDALONE=1> and providing your configuration in
2797	whatever way you want, you can also C<m4_include([libev.m4])> in your	2852	whatever way you want, you can also C<m4_include([libev.m4])> in your
2798	F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then	2853	F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then
2799	include F<config.h> and configure itself accordingly.	2854	include F<config.h> and configure itself accordingly.
2800		2855
2801	For this of course you need the m4 file:	2856	For this of course you need the m4 file:
2802		2857
2803	libev.m4	2858	libev.m4
2804		2859
2805	=head2 PREPROCESSOR SYMBOLS/MACROS	2860	=head2 PREPROCESSOR SYMBOLS/MACROS
2806		2861
2807	Libev can be configured via a variety of preprocessor symbols you have to	2862	Libev can be configured via a variety of preprocessor symbols you have to
2808	define before including any of its files. The default in the absence of	2863	define before including any of its files. The default in the absence of
…		…
3085	members. You have to define it each time you include one of the files,	3140	members. You have to define it each time you include one of the files,
3086	though, and it must be identical each time.	3141	though, and it must be identical each time.
3087		3142
3088	For example, the perl EV module uses something like this:	3143	For example, the perl EV module uses something like this:
3089		3144
3090	#define EV_COMMON \	3145	#define EV_COMMON \
3091	SV self; / contains this struct */ \	3146	SV self; / contains this struct */ \
3092	SV cb_sv, fh /* note no trailing ";" */	3147	SV cb_sv, fh /* note no trailing ";" */
3093		3148
3094	=item EV_CB_DECLARE (type)	3149	=item EV_CB_DECLARE (type)
3095		3150
3096	=item EV_CB_INVOKE (watcher, revents)	3151	=item EV_CB_INVOKE (watcher, revents)
3097		3152
…		…
3108		3163
3109	If you need to re-export the API (e.g. via a DLL) and you need a list of	3164	If you need to re-export the API (e.g. via a DLL) and you need a list of
3110	exported symbols, you can use the provided F<Symbol.*> files which list	3165	exported symbols, you can use the provided F<Symbol.*> files which list
3111	all public symbols, one per line:	3166	all public symbols, one per line:
3112		3167
3113	Symbols.ev for libev proper	3168	Symbols.ev for libev proper
3114	Symbols.event for the libevent emulation	3169	Symbols.event for the libevent emulation
3115		3170
3116	This can also be used to rename all public symbols to avoid clashes with	3171	This can also be used to rename all public symbols to avoid clashes with
3117	multiple versions of libev linked together (which is obviously bad in	3172	multiple versions of libev linked together (which is obviously bad in
3118	itself, but sometimes it is inconvenient to avoid this).	3173	itself, but sometimes it is inconvenient to avoid this).
3119		3174
…		…
3140	file.	3195	file.
3141		3196
3142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	3197	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
3143	that everybody includes and which overrides some configure choices:	3198	that everybody includes and which overrides some configure choices:
3144		3199
3145	#define EV_MINIMAL 1	3200	#define EV_MINIMAL 1
3146	#define EV_USE_POLL 0	3201	#define EV_USE_POLL 0
3147	#define EV_MULTIPLICITY 0	3202	#define EV_MULTIPLICITY 0
3148	#define EV_PERIODIC_ENABLE 0	3203	#define EV_PERIODIC_ENABLE 0
3149	#define EV_STAT_ENABLE 0	3204	#define EV_STAT_ENABLE 0
3150	#define EV_FORK_ENABLE 0	3205	#define EV_FORK_ENABLE 0
3151	#define EV_CONFIG_H <config.h>	3206	#define EV_CONFIG_H <config.h>
3152	#define EV_MINPRI 0	3207	#define EV_MINPRI 0
3153	#define EV_MAXPRI 0	3208	#define EV_MAXPRI 0
3154		3209
3155	#include "ev++.h"	3210	#include "ev++.h"
3156		3211
3157	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	3212	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3158		3213
3159	#include "ev_cpp.h"	3214	#include "ev_cpp.h"
3160	#include "ev.c"	3215	#include "ev.c"
3161		3216
3162		3217
3163	=head1 THREADS AND COROUTINES	3218	=head1 THREADS AND COROUTINES
3164		3219
3165	=head2 THREADS	3220	=head2 THREADS
…		…
3173	parallel from multiple threads, calls with the same loop parameter must be	3228	parallel from multiple threads, calls with the same loop parameter must be
3174	done serially (but can be done from different threads, as long as only one	3229	done serially (but can be done from different threads, as long as only one
3175	thread ever is inside a call at any point in time, e.g. by using a mutex	3230	thread ever is inside a call at any point in time, e.g. by using a mutex
3176	per loop).	3231	per loop).
3177		3232
3178	If you want to know which design is best for your problem, then I cannot	3233	If you want to know which design (one loop, locking, or multiple loops
3179	help you but by giving some generic advice:	3234	without or something else still) is best for your problem, then I cannot
		3235	help you. I can give some generic advice however:
3180		3236
3181	=over 4	3237	=over 4
3182		3238
3183	=item * most applications have a main thread: use the default libev loop	3239	=item * most applications have a main thread: use the default libev loop
3184	in that thread, or create a separate thread running only the default loop.	3240	in that thread, or create a separate thread running only the default loop.
…		…
3317	more than a hundred or so sockets, then likely it needs to use a totally	3373	more than a hundred or so sockets, then likely it needs to use a totally
3318	different implementation for windows, as libev offers the POSIX readiness	3374	different implementation for windows, as libev offers the POSIX readiness
3319	notification model, which cannot be implemented efficiently on windows	3375	notification model, which cannot be implemented efficiently on windows
3320	(Microsoft monopoly games).	3376	(Microsoft monopoly games).
3321		3377
		3378	A typical way to use libev under windows is to embed it (see the embedding
		3379	section for details) and use the following F<evwrap.h> header file instead
		3380	of F<ev.h>:
		3381
		3382	#define EV_STANDALONE /* keeps ev from requiring config.h */
		3383	#define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
		3384
		3385	#include "ev.h"
		3386
		3387	And compile the following F<evwrap.c> file into your project (make sure
		3388	you do I<not> compile the F<ev.c> or any other embedded soruce files!):
		3389
		3390	#include "evwrap.h"
		3391	#include "ev.c"
		3392
3322	=over 4	3393	=over 4
3323		3394
3324	=item The winsocket select function	3395	=item The winsocket select function
3325		3396
3326	The winsocket C<select> function doesn't follow POSIX in that it	3397	The winsocket C<select> function doesn't follow POSIX in that it
3327	requires socket I<handles> and not socket I<file descriptors> (it is	3398	requires socket I<handles> and not socket I<file descriptors> (it is
3328	also extremely buggy). This makes select very inefficient, and also	3399	also extremely buggy). This makes select very inefficient, and also
3329	requires a mapping from file descriptors to socket handles. See the	3400	requires a mapping from file descriptors to socket handles (the Microsoft
		3401	C runtime provides the function C<_open_osfhandle> for this). See the
3330	discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and	3402	discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and
3331	C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.	3403	C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.
3332		3404
3333	The configuration for a "naked" win32 using the Microsoft runtime	3405	The configuration for a "naked" win32 using the Microsoft runtime
3334	libraries and raw winsocket select is:	3406	libraries and raw winsocket select is:
3335		3407
3336	#define EV_USE_SELECT 1	3408	#define EV_USE_SELECT 1
3337	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	3409	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
3338		3410
3339	Note that winsockets handling of fd sets is O(n), so you can easily get a	3411	Note that winsockets handling of fd sets is O(n), so you can easily get a
3340	complexity in the O(n²) range when using win32.	3412	complexity in the O(n²) range when using win32.
3341		3413
3342	=item Limited number of file descriptors	3414	=item Limited number of file descriptors
…		…
3374	In addition to a working ISO-C implementation, libev relies on a few	3446	In addition to a working ISO-C implementation, libev relies on a few
3375	additional extensions:	3447	additional extensions:
3376		3448
3377	=over 4	3449	=over 4
3378		3450
		3451	=item C<void ()(ev_watcher_type , int revents)> must have compatible
		3452	calling conventions regardless of C<ev_watcher_type *>.
		3453
		3454	Libev assumes not only that all watcher pointers have the same internal
		3455	structure (guaranteed by POSIX but not by ISO C for example), but it also
		3456	assumes that the same (machine) code can be used to call any watcher
		3457	callback: The watcher callbacks have different type signatures, but libev
		3458	calls them using an C<ev_watcher *> internally.
		3459
3379	=item C<sig_atomic_t volatile> must be thread-atomic as well	3460	=item C<sig_atomic_t volatile> must be thread-atomic as well
3380		3461
3381	The type C<sig_atomic_t volatile> (or whatever is defined as	3462	The type C<sig_atomic_t volatile> (or whatever is defined as
3382	C<EV_ATOMIC_T>) must be atomic w.r.t. accesses from different	3463	C<EV_ATOMIC_T>) must be atomic w.r.t. accesses from different
3383	threads. This is not part of the specification for C<sig_atomic_t>, but is	3464	threads. This is not part of the specification for C<sig_atomic_t>, but is

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