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

View File | Revision Log | Show Annotations | Download File

/cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.163 by root, Sat May 31 23:19:23 2008 UTC vs.
Revision 1.178 by root, Sat Sep 13 18:25:50 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	};
		1012
		1013	...
		1014	struct my_io w;
		1015	ev_io_init (&w.io, my_cb, fd, EV_READ);
990		1016
991	And since your callback will be called with a pointer to the watcher, you	1017	And since your callback will be called with a pointer to the watcher, you
992	can cast it back to your own type:	1018	can cast it back to your own type:
993		1019
994	static void my_cb (struct ev_loop loop, struct ev_io w_, int revents)	1020	static void my_cb (struct ev_loop loop, struct ev_io w_, int revents)
995	{	1021	{
996	struct my_io w = (struct my_io )w_;	1022	struct my_io w = (struct my_io )w_;
997	...	1023	...
998	}	1024	}
999		1025
1000	More interesting and less C-conformant ways of casting your callback type	1026	More interesting and less C-conformant ways of casting your callback type
1001	instead have been omitted.	1027	instead have been omitted.
1002		1028
1003	Another common scenario is having some data structure with multiple	1029	Another common scenario is to use some data structure with multiple
1004	watchers:	1030	embedded watchers:
1005		1031
1006	struct my_biggy	1032	struct my_biggy
1007	{	1033	{
1008	int some_data;	1034	int some_data;
1009	ev_timer t1;	1035	ev_timer t1;
1010	ev_timer t2;	1036	ev_timer t2;
1011	}	1037	}
1012		1038
1013	In this case getting the pointer to C<my_biggy> is a bit more complicated,	1039	In this case getting the pointer to C<my_biggy> is a bit more
1014	you need to use C<offsetof>:	1040	complicated: Either you store the address of your C<my_biggy> struct
		1041	in the C<data> member of the watcher, or you need to use some pointer
		1042	arithmetic using C<offsetof> inside your watchers:
1015		1043
1016	#include <stddef.h>	1044	#include <stddef.h>
1017		1045
1018	static void	1046	static void
1019	t1_cb (EV_P_ struct ev_timer *w, int revents)	1047	t1_cb (EV_P_ struct ev_timer *w, int revents)
1020	{	1048	{
1021	struct my_biggy big = (struct my_biggy *	1049	struct my_biggy big = (struct my_biggy *
1022	(((char *)w) - offsetof (struct my_biggy, t1));	1050	(((char *)w) - offsetof (struct my_biggy, t1));
1023	}	1051	}
1024		1052
1025	static void	1053	static void
1026	t2_cb (EV_P_ struct ev_timer *w, int revents)	1054	t2_cb (EV_P_ struct ev_timer *w, int revents)
1027	{	1055	{
1028	struct my_biggy big = (struct my_biggy *	1056	struct my_biggy big = (struct my_biggy *
1029	(((char *)w) - offsetof (struct my_biggy, t2));	1057	(((char *)w) - offsetof (struct my_biggy, t2));
1030	}	1058	}
1031		1059
1032		1060
1033	=head1 WATCHER TYPES	1061	=head1 WATCHER TYPES
1034		1062
1035	This section describes each watcher in detail, but will not repeat	1063	This section describes each watcher in detail, but will not repeat
…		…
1124	C<EVBACKEND_POLL>.	1152	C<EVBACKEND_POLL>.
1125		1153
1126	=head3 The special problem of SIGPIPE	1154	=head3 The special problem of SIGPIPE
1127		1155
1128	While not really specific to libev, it is easy to forget about SIGPIPE:	1156	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	1157	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	1158	send a SIGPIPE, which, by default, aborts your program. For most programs
1131	programs this is sensible behaviour, for daemons, this is usually	1159	this is sensible behaviour, for daemons, this is usually undesirable.
1132	undesirable.
1133		1160
1134	So when you encounter spurious, unexplained daemon exits, make sure you	1161	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	1162	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).	1163	somewhere, as that would have given you a big clue).
1137		1164
…		…
1162		1189
1163	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well	1190	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	1191	readable, but only once. Since it is likely line-buffered, you could
1165	attempt to read a whole line in the callback.	1192	attempt to read a whole line in the callback.
1166		1193
1167	static void	1194	static void
1168	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	1195	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
1169	{	1196	{
1170	ev_io_stop (loop, w);	1197	ev_io_stop (loop, w);
1171	.. read from stdin here (or from w->fd) and haqndle any I/O errors	1198	.. read from stdin here (or from w->fd) and haqndle any I/O errors
1172	}	1199	}
1173		1200
1174	...	1201	...
1175	struct ev_loop *loop = ev_default_init (0);	1202	struct ev_loop *loop = ev_default_init (0);
1176	struct ev_io stdin_readable;	1203	struct ev_io stdin_readable;
1177	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1204	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1178	ev_io_start (loop, &stdin_readable);	1205	ev_io_start (loop, &stdin_readable);
1179	ev_loop (loop, 0);	1206	ev_loop (loop, 0);
1180		1207
1181		1208
1182	=head2 C<ev_timer> - relative and optionally repeating timeouts	1209	=head2 C<ev_timer> - relative and optionally repeating timeouts
1183		1210
1184	Timer watchers are simple relative timers that generate an event after a	1211	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	1215	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	1216	year, it will still time out after (roughly) and hour. "Roughly" because
1190	detecting time jumps is hard, and some inaccuracies are unavoidable (the	1217	detecting time jumps is hard, and some inaccuracies are unavoidable (the
1191	monotonic clock option helps a lot here).	1218	monotonic clock option helps a lot here).
1192		1219
		1220	The callback is guaranteed to be invoked only after its timeout has passed,
		1221	but if multiple timers become ready during the same loop iteration then
		1222	order of execution is undefined.
		1223
		1224	=head3 The special problem of time updates
		1225
		1226	Establishing the current time is a costly operation (it usually takes at
		1227	least two system calls): EV therefore updates its idea of the current
		1228	time only before and after C<ev_loop> polls for new events, which causes
		1229	a growing difference between C<ev_now ()> and C<ev_time ()> when handling
		1230	lots of events.
		1231
1193	The relative timeouts are calculated relative to the C<ev_now ()>	1232	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	1233	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	1234	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	1235	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:	1236	timeout on the current time, use something like this to adjust for this:
1198		1237
1199	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);	1238	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
1200		1239
1201	The callback is guaranteed to be invoked only after its timeout has passed,	1240	If the event loop is suspended for a long time, you can also force an
1202	but if multiple timers become ready during the same loop iteration then	1241	update of the time returned by C<ev_now ()> by calling C<ev_now_update
1203	order of execution is undefined.	1242	()>.
1204		1243
1205	=head3 Watcher-Specific Functions and Data Members	1244	=head3 Watcher-Specific Functions and Data Members
1206		1245
1207	=over 4	1246	=over 4
1208		1247
…		…
1269		1308
1270	=head3 Examples	1309	=head3 Examples
1271		1310
1272	Example: Create a timer that fires after 60 seconds.	1311	Example: Create a timer that fires after 60 seconds.
1273		1312
1274	static void	1313	static void
1275	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1314	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
1276	{	1315	{
1277	.. one minute over, w is actually stopped right here	1316	.. one minute over, w is actually stopped right here
1278	}	1317	}
1279		1318
1280	struct ev_timer mytimer;	1319	struct ev_timer mytimer;
1281	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1320	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1282	ev_timer_start (loop, &mytimer);	1321	ev_timer_start (loop, &mytimer);
1283		1322
1284	Example: Create a timeout timer that times out after 10 seconds of	1323	Example: Create a timeout timer that times out after 10 seconds of
1285	inactivity.	1324	inactivity.
1286		1325
1287	static void	1326	static void
1288	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1327	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
1289	{	1328	{
1290	.. ten seconds without any activity	1329	.. ten seconds without any activity
1291	}	1330	}
1292		1331
1293	struct ev_timer mytimer;	1332	struct ev_timer mytimer;
1294	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	1333	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1295	ev_timer_again (&mytimer); /* start timer */	1334	ev_timer_again (&mytimer); /* start timer */
1296	ev_loop (loop, 0);	1335	ev_loop (loop, 0);
1297		1336
1298	// and in some piece of code that gets executed on any "activity":	1337	// and in some piece of code that gets executed on any "activity":
1299	// reset the timeout to start ticking again at 10 seconds	1338	// reset the timeout to start ticking again at 10 seconds
1300	ev_timer_again (&mytimer);	1339	ev_timer_again (&mytimer);
1301		1340
1302		1341
1303	=head2 C<ev_periodic> - to cron or not to cron?	1342	=head2 C<ev_periodic> - to cron or not to cron?
1304		1343
1305	Periodic watchers are also timers of a kind, but they are very versatile	1344	Periodic watchers are also timers of a kind, but they are very versatile
…		…
1448		1487
1449	Example: Call a callback every hour, or, more precisely, whenever the	1488	Example: Call a callback every hour, or, more precisely, whenever the
1450	system clock is divisible by 3600. The callback invocation times have	1489	system clock is divisible by 3600. The callback invocation times have
1451	potentially a lot of jitter, but good long-term stability.	1490	potentially a lot of jitter, but good long-term stability.
1452		1491
1453	static void	1492	static void
1454	clock_cb (struct ev_loop loop, struct ev_io w, int revents)	1493	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
1455	{	1494	{
1456	... its now a full hour (UTC, or TAI or whatever your clock follows)	1495	... its now a full hour (UTC, or TAI or whatever your clock follows)
1457	}	1496	}
1458		1497
1459	struct ev_periodic hourly_tick;	1498	struct ev_periodic hourly_tick;
1460	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1499	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1461	ev_periodic_start (loop, &hourly_tick);	1500	ev_periodic_start (loop, &hourly_tick);
1462		1501
1463	Example: The same as above, but use a reschedule callback to do it:	1502	Example: The same as above, but use a reschedule callback to do it:
1464		1503
1465	#include <math.h>	1504	#include <math.h>
1466		1505
1467	static ev_tstamp	1506	static ev_tstamp
1468	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1507	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1469	{	1508	{
1470	return fmod (now, 3600.) + 3600.;	1509	return fmod (now, 3600.) + 3600.;
1471	}	1510	}
1472		1511
1473	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1512	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1474		1513
1475	Example: Call a callback every hour, starting now:	1514	Example: Call a callback every hour, starting now:
1476		1515
1477	struct ev_periodic hourly_tick;	1516	struct ev_periodic hourly_tick;
1478	ev_periodic_init (&hourly_tick, clock_cb,	1517	ev_periodic_init (&hourly_tick, clock_cb,
1479	fmod (ev_now (loop), 3600.), 3600., 0);	1518	fmod (ev_now (loop), 3600.), 3600., 0);
1480	ev_periodic_start (loop, &hourly_tick);	1519	ev_periodic_start (loop, &hourly_tick);
1481		1520
1482		1521
1483	=head2 C<ev_signal> - signal me when a signal gets signalled!	1522	=head2 C<ev_signal> - signal me when a signal gets signalled!
1484		1523
1485	Signal watchers will trigger an event when the process receives a specific	1524	Signal watchers will trigger an event when the process receives a specific
…		…
1519		1558
1520	=head3 Examples	1559	=head3 Examples
1521		1560
1522	Example: Try to exit cleanly on SIGINT and SIGTERM.	1561	Example: Try to exit cleanly on SIGINT and SIGTERM.
1523		1562
1524	static void	1563	static void
1525	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1564	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1526	{	1565	{
1527	ev_unloop (loop, EVUNLOOP_ALL);	1566	ev_unloop (loop, EVUNLOOP_ALL);
1528	}	1567	}
1529		1568
1530	struct ev_signal signal_watcher;	1569	struct ev_signal signal_watcher;
1531	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1570	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1532	ev_signal_start (loop, &sigint_cb);	1571	ev_signal_start (loop, &sigint_cb);
1533		1572
1534		1573
1535	=head2 C<ev_child> - watch out for process status changes	1574	=head2 C<ev_child> - watch out for process status changes
1536		1575
1537	Child watchers trigger when your process receives a SIGCHLD in response to	1576	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	1598	handler, you can override it easily by installing your own handler for
1560	C<SIGCHLD> after initialising the default loop, and making sure the	1599	C<SIGCHLD> after initialising the default loop, and making sure the
1561	default loop never gets destroyed. You are encouraged, however, to use an	1600	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	1601	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.	1602	that, so other libev users can use C<ev_child> watchers freely.
		1603
		1604	=head3 Stopping the Child Watcher
		1605
		1606	Currently, the child watcher never gets stopped, even when the
		1607	child terminates, so normally one needs to stop the watcher in the
		1608	callback. Future versions of libev might stop the watcher automatically
		1609	when a child exit is detected.
1564		1610
1565	=head3 Watcher-Specific Functions and Data Members	1611	=head3 Watcher-Specific Functions and Data Members
1566		1612
1567	=over 4	1613	=over 4
1568		1614
…		…
1597	=head3 Examples	1643	=head3 Examples
1598		1644
1599	Example: C<fork()> a new process and install a child handler to wait for	1645	Example: C<fork()> a new process and install a child handler to wait for
1600	its completion.	1646	its completion.
1601		1647
1602	ev_child cw;	1648	ev_child cw;
1603		1649
1604	static void	1650	static void
1605	child_cb (EV_P_ struct ev_child *w, int revents)	1651	child_cb (EV_P_ struct ev_child *w, int revents)
1606	{	1652	{
1607	ev_child_stop (EV_A_ w);	1653	ev_child_stop (EV_A_ w);
1608	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);	1654	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
1609	}	1655	}
1610		1656
1611	pid_t pid = fork ();	1657	pid_t pid = fork ();
1612		1658
1613	if (pid < 0)	1659	if (pid < 0)
1614	// error	1660	// error
1615	else if (pid == 0)	1661	else if (pid == 0)
1616	{	1662	{
1617	// the forked child executes here	1663	// the forked child executes here
1618	exit (1);	1664	exit (1);
1619	}	1665	}
1620	else	1666	else
1621	{	1667	{
1622	ev_child_init (&cw, child_cb, pid, 0);	1668	ev_child_init (&cw, child_cb, pid, 0);
1623	ev_child_start (EV_DEFAULT_ &cw);	1669	ev_child_start (EV_DEFAULT_ &cw);
1624	}	1670	}
1625		1671
1626		1672
1627	=head2 C<ev_stat> - did the file attributes just change?	1673	=head2 C<ev_stat> - did the file attributes just change?
1628		1674
1629	This watches a file system path for attribute changes. That is, it calls	1675	This watches a file system path for attribute changes. That is, it calls
…		…
1662	will be no polling.	1708	will be no polling.
1663		1709
1664	=head3 ABI Issues (Largefile Support)	1710	=head3 ABI Issues (Largefile Support)
1665		1711
1666	Libev by default (unless the user overrides this) uses the default	1712	Libev by default (unless the user overrides this) uses the default
1667	compilation environment, which means that on systems with optionally	1713	compilation environment, which means that on systems with large file
1668	disabled large file support, you get the 32 bit version of the stat	1714	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	1715	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	1716	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	1717	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	1718	obviously the case with any flags that change the ABI, but the problem is
1673	most noticeably with ev_stat and large file support.	1719	most noticeably disabled with ev_stat and large file support.
		1720
		1721	The solution for this is to lobby your distribution maker to make large
		1722	file interfaces available by default (as e.g. FreeBSD does) and not
		1723	optional. Libev cannot simply switch on large file support because it has
		1724	to exchange stat structures with application programs compiled using the
		1725	default compilation environment.
1674		1726
1675	=head3 Inotify	1727	=head3 Inotify
1676		1728
1677	When C<inotify (7)> support has been compiled into libev (generally only	1729	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	1730	available on Linux) and present at runtime, it will be used to speed up
…		…
1767		1819
1768	=head3 Examples	1820	=head3 Examples
1769		1821
1770	Example: Watch C</etc/passwd> for attribute changes.	1822	Example: Watch C</etc/passwd> for attribute changes.
1771		1823
1772	static void	1824	static void
1773	passwd_cb (struct ev_loop loop, ev_stat w, int revents)	1825	passwd_cb (struct ev_loop loop, ev_stat w, int revents)
1774	{	1826	{
1775	/* /etc/passwd changed in some way */	1827	/* /etc/passwd changed in some way */
1776	if (w->attr.st_nlink)	1828	if (w->attr.st_nlink)
1777	{	1829	{
1778	printf ("passwd current size %ld\n", (long)w->attr.st_size);	1830	printf ("passwd current size %ld\n", (long)w->attr.st_size);
1779	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);	1831	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
1780	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);	1832	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
1781	}	1833	}
1782	else	1834	else
1783	/* you shalt not abuse printf for puts */	1835	/* you shalt not abuse printf for puts */
1784	puts ("wow, /etc/passwd is not there, expect problems. "	1836	puts ("wow, /etc/passwd is not there, expect problems. "
1785	"if this is windows, they already arrived\n");	1837	"if this is windows, they already arrived\n");
1786	}	1838	}
1787		1839
1788	...	1840	...
1789	ev_stat passwd;	1841	ev_stat passwd;
1790		1842
1791	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);	1843	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
1792	ev_stat_start (loop, &passwd);	1844	ev_stat_start (loop, &passwd);
1793		1845
1794	Example: Like above, but additionally use a one-second delay so we do not	1846	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	1847	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	1848	one might do the work both on C<ev_stat> callback invocation I<and> on
1797	C<ev_timer> callback invocation).	1849	C<ev_timer> callback invocation).
1798		1850
1799	static ev_stat passwd;	1851	static ev_stat passwd;
1800	static ev_timer timer;	1852	static ev_timer timer;
1801		1853
1802	static void	1854	static void
1803	timer_cb (EV_P_ ev_timer *w, int revents)	1855	timer_cb (EV_P_ ev_timer *w, int revents)
1804	{	1856	{
1805	ev_timer_stop (EV_A_ w);	1857	ev_timer_stop (EV_A_ w);
1806		1858
1807	/* now it's one second after the most recent passwd change */	1859	/* now it's one second after the most recent passwd change */
1808	}	1860	}
1809		1861
1810	static void	1862	static void
1811	stat_cb (EV_P_ ev_stat *w, int revents)	1863	stat_cb (EV_P_ ev_stat *w, int revents)
1812	{	1864	{
1813	/* reset the one-second timer */	1865	/* reset the one-second timer */
1814	ev_timer_again (EV_A_ &timer);	1866	ev_timer_again (EV_A_ &timer);
1815	}	1867	}
1816		1868
1817	...	1869	...
1818	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);	1870	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
1819	ev_stat_start (loop, &passwd);	1871	ev_stat_start (loop, &passwd);
1820	ev_timer_init (&timer, timer_cb, 0., 1.02);	1872	ev_timer_init (&timer, timer_cb, 0., 1.02);
1821		1873
1822		1874
1823	=head2 C<ev_idle> - when you've got nothing better to do...	1875	=head2 C<ev_idle> - when you've got nothing better to do...
1824		1876
1825	Idle watchers trigger events when no other events of the same or higher	1877	Idle watchers trigger events when no other events of the same or higher
…		…
1856	=head3 Examples	1908	=head3 Examples
1857		1909
1858	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the	1910	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1859	callback, free it. Also, use no error checking, as usual.	1911	callback, free it. Also, use no error checking, as usual.
1860		1912
1861	static void	1913	static void
1862	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1914	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1863	{	1915	{
1864	free (w);	1916	free (w);
1865	// now do something you wanted to do when the program has	1917	// now do something you wanted to do when the program has
1866	// no longer anything immediate to do.	1918	// no longer anything immediate to do.
1867	}	1919	}
1868		1920
1869	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1921	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1870	ev_idle_init (idle_watcher, idle_cb);	1922	ev_idle_init (idle_watcher, idle_cb);
1871	ev_idle_start (loop, idle_cb);	1923	ev_idle_start (loop, idle_cb);
1872		1924
1873		1925
1874	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!	1926	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
1875		1927
1876	Prepare and check watchers are usually (but not always) used in tandem:	1928	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	2000	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	2001	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	2002	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.	2003	the callbacks for the IO/timeout watchers might not have been called yet.
1952		2004
1953	static ev_io iow [nfd];	2005	static ev_io iow [nfd];
1954	static ev_timer tw;	2006	static ev_timer tw;
1955		2007
1956	static void	2008	static void
1957	io_cb (ev_loop loop, ev_io w, int revents)	2009	io_cb (ev_loop loop, ev_io w, int revents)
1958	{	2010	{
1959	}	2011	}
1960		2012
1961	// create io watchers for each fd and a timer before blocking	2013	// create io watchers for each fd and a timer before blocking
1962	static void	2014	static void
1963	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	2015	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1964	{	2016	{
1965	int timeout = 3600000;	2017	int timeout = 3600000;
1966	struct pollfd fds [nfd];	2018	struct pollfd fds [nfd];
1967	// actual code will need to loop here and realloc etc.	2019	// actual code will need to loop here and realloc etc.
1968	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	2020	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1969		2021
1970	/* the callback is illegal, but won't be called as we stop during check */	2022	/* the callback is illegal, but won't be called as we stop during check */
1971	ev_timer_init (&tw, 0, timeout * 1e-3);	2023	ev_timer_init (&tw, 0, timeout * 1e-3);
1972	ev_timer_start (loop, &tw);	2024	ev_timer_start (loop, &tw);
1973		2025
1974	// create one ev_io per pollfd	2026	// create one ev_io per pollfd
1975	for (int i = 0; i < nfd; ++i)	2027	for (int i = 0; i < nfd; ++i)
1976	{	2028	{
1977	ev_io_init (iow + i, io_cb, fds [i].fd,	2029	ev_io_init (iow + i, io_cb, fds [i].fd,
1978	((fds [i].events & POLLIN ? EV_READ : 0)	2030	((fds [i].events & POLLIN ? EV_READ : 0)
1979	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	2031	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1980		2032
1981	fds [i].revents = 0;	2033	fds [i].revents = 0;
1982	ev_io_start (loop, iow + i);	2034	ev_io_start (loop, iow + i);
1983	}	2035	}
1984	}	2036	}
1985		2037
1986	// stop all watchers after blocking	2038	// stop all watchers after blocking
1987	static void	2039	static void
1988	adns_check_cb (ev_loop loop, ev_check w, int revents)	2040	adns_check_cb (ev_loop loop, ev_check w, int revents)
1989	{	2041	{
1990	ev_timer_stop (loop, &tw);	2042	ev_timer_stop (loop, &tw);
1991		2043
1992	for (int i = 0; i < nfd; ++i)	2044	for (int i = 0; i < nfd; ++i)
1993	{	2045	{
1994	// set the relevant poll flags	2046	// set the relevant poll flags
1995	// could also call adns_processreadable etc. here	2047	// could also call adns_processreadable etc. here
1996	struct pollfd *fd = fds + i;	2048	struct pollfd *fd = fds + i;
1997	int revents = ev_clear_pending (iow + i);	2049	int revents = ev_clear_pending (iow + i);
1998	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;	2050	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1999	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;	2051	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
2000		2052
2001	// now stop the watcher	2053	// now stop the watcher
2002	ev_io_stop (loop, iow + i);	2054	ev_io_stop (loop, iow + i);
2003	}	2055	}
2004		2056
2005	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	2057	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
2006	}	2058	}
2007		2059
2008	Method 2: This would be just like method 1, but you run C<adns_afterpoll>	2060	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.	2061	in the prepare watcher and would dispose of the check watcher.
2010		2062
2011	Method 3: If the module to be embedded supports explicit event	2063	Method 3: If the module to be embedded supports explicit event
2012	notification (libadns does), you can also make use of the actual watcher	2064	notification (libadns does), you can also make use of the actual watcher
2013	callbacks, and only destroy/create the watchers in the prepare watcher.	2065	callbacks, and only destroy/create the watchers in the prepare watcher.
2014		2066
2015	static void	2067	static void
2016	timer_cb (EV_P_ ev_timer *w, int revents)	2068	timer_cb (EV_P_ ev_timer *w, int revents)
2017	{	2069	{
2018	adns_state ads = (adns_state)w->data;	2070	adns_state ads = (adns_state)w->data;
2019	update_now (EV_A);	2071	update_now (EV_A);
2020		2072
2021	adns_processtimeouts (ads, &tv_now);	2073	adns_processtimeouts (ads, &tv_now);
2022	}	2074	}
2023		2075
2024	static void	2076	static void
2025	io_cb (EV_P_ ev_io *w, int revents)	2077	io_cb (EV_P_ ev_io *w, int revents)
2026	{	2078	{
2027	adns_state ads = (adns_state)w->data;	2079	adns_state ads = (adns_state)w->data;
2028	update_now (EV_A);	2080	update_now (EV_A);
2029		2081
2030	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);	2082	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
2031	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);	2083	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
2032	}	2084	}
2033		2085
2034	// do not ever call adns_afterpoll	2086	// do not ever call adns_afterpoll
2035		2087
2036	Method 4: Do not use a prepare or check watcher because the module you	2088	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	2089	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	2090	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	2091	loop is now no longer controllable by EV. The C<Glib::EV> module does
2040	this.	2092	this.
2041		2093
2042	static gint	2094	static gint
2043	event_poll_func (GPollFD *fds, guint nfds, gint timeout)	2095	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
2044	{	2096	{
2045	int got_events = 0;	2097	int got_events = 0;
2046		2098
2047	for (n = 0; n < nfds; ++n)	2099	for (n = 0; n < nfds; ++n)
2048	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events	2100	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
2049		2101
2050	if (timeout >= 0)	2102	if (timeout >= 0)
2051	// create/start timer	2103	// create/start timer
2052		2104
2053	// poll	2105	// poll
2054	ev_loop (EV_A_ 0);	2106	ev_loop (EV_A_ 0);
2055		2107
2056	// stop timer again	2108	// stop timer again
2057	if (timeout >= 0)	2109	if (timeout >= 0)
2058	ev_timer_stop (EV_A_ &to);	2110	ev_timer_stop (EV_A_ &to);
2059		2111
2060	// stop io watchers again - their callbacks should have set	2112	// stop io watchers again - their callbacks should have set
2061	for (n = 0; n < nfds; ++n)	2113	for (n = 0; n < nfds; ++n)
2062	ev_io_stop (EV_A_ iow [n]);	2114	ev_io_stop (EV_A_ iow [n]);
2063		2115
2064	return got_events;	2116	return got_events;
2065	}	2117	}
2066		2118
2067		2119
2068	=head2 C<ev_embed> - when one backend isn't enough...	2120	=head2 C<ev_embed> - when one backend isn't enough...
2069		2121
2070	This is a rather advanced watcher type that lets you embed one event loop	2122	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	2200	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	2201	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	2202	C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
2151	used).	2203	used).
2152		2204
2153	struct ev_loop *loop_hi = ev_default_init (0);	2205	struct ev_loop *loop_hi = ev_default_init (0);
2154	struct ev_loop *loop_lo = 0;	2206	struct ev_loop *loop_lo = 0;
2155	struct ev_embed embed;	2207	struct ev_embed embed;
2156		2208
2157	// see if there is a chance of getting one that works	2209	// see if there is a chance of getting one that works
2158	// (remember that a flags value of 0 means autodetection)	2210	// (remember that a flags value of 0 means autodetection)
2159	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()	2211	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
2160	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())	2212	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
2161	: 0;	2213	: 0;
2162		2214
2163	// if we got one, then embed it, otherwise default to loop_hi	2215	// if we got one, then embed it, otherwise default to loop_hi
2164	if (loop_lo)	2216	if (loop_lo)
2165	{	2217	{
2166	ev_embed_init (&embed, 0, loop_lo);	2218	ev_embed_init (&embed, 0, loop_lo);
2167	ev_embed_start (loop_hi, &embed);	2219	ev_embed_start (loop_hi, &embed);
2168	}	2220	}
2169	else	2221	else
2170	loop_lo = loop_hi;	2222	loop_lo = loop_hi;
2171		2223
2172	Example: Check if kqueue is available but not recommended and create	2224	Example: Check if kqueue is available but not recommended and create
2173	a kqueue backend for use with sockets (which usually work with any	2225	a kqueue backend for use with sockets (which usually work with any
2174	kqueue implementation). Store the kqueue/socket-only event loop in	2226	kqueue implementation). Store the kqueue/socket-only event loop in
2175	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).	2227	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
2176		2228
2177	struct ev_loop *loop = ev_default_init (0);	2229	struct ev_loop *loop = ev_default_init (0);
2178	struct ev_loop *loop_socket = 0;	2230	struct ev_loop *loop_socket = 0;
2179	struct ev_embed embed;	2231	struct ev_embed embed;
2180		2232
2181	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)	2233	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
2182	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))	2234	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
2183	{	2235	{
2184	ev_embed_init (&embed, 0, loop_socket);	2236	ev_embed_init (&embed, 0, loop_socket);
2185	ev_embed_start (loop, &embed);	2237	ev_embed_start (loop, &embed);
2186	}	2238	}
2187		2239
2188	if (!loop_socket)	2240	if (!loop_socket)
2189	loop_socket = loop;	2241	loop_socket = loop;
2190		2242
2191	// now use loop_socket for all sockets, and loop for everything else	2243	// now use loop_socket for all sockets, and loop for everything else
2192		2244
2193		2245
2194	=head2 C<ev_fork> - the audacity to resume the event loop after a fork	2246	=head2 C<ev_fork> - the audacity to resume the event loop after a fork
2195		2247
2196	Fork watchers are called when a C<fork ()> was detected (usually because	2248	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	2437	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	2438	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>	2439	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
2388	value passed to C<ev_once>:	2440	value passed to C<ev_once>:
2389		2441
2390	static void stdin_ready (int revents, void *arg)	2442	static void stdin_ready (int revents, void *arg)
2391	{	2443	{
2392	if (revents & EV_TIMEOUT)	2444	if (revents & EV_TIMEOUT)
2393	/* doh, nothing entered */;	2445	/* doh, nothing entered */;
2394	else if (revents & EV_READ)	2446	else if (revents & EV_READ)
2395	/* stdin might have data for us, joy! */;	2447	/* stdin might have data for us, joy! */;
2396	}	2448	}
2397		2449
2398	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2450	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2399		2451
2400	=item ev_feed_event (ev_loop , watcher , int revents)	2452	=item ev_feed_event (ev_loop , watcher , int revents)
2401		2453
2402	Feeds the given event set into the event loop, as if the specified event	2454	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	2455	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	2504	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.	2505	the callback model to a model using method callbacks on objects.
2454		2506
2455	To use it,	2507	To use it,
2456		2508
2457	#include <ev++.h>	2509	#include <ev++.h>
2458		2510
2459	This automatically includes F<ev.h> and puts all of its definitions (many	2511	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	2512	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	2513	put into the C<ev> namespace. It should support all the same embedding
2462	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.	2514	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
…		…
2529	your compiler is good :), then the method will be fully inlined into the	2581	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.	2582	thunking function, making it as fast as a direct C callback.
2531		2583
2532	Example: simple class declaration and watcher initialisation	2584	Example: simple class declaration and watcher initialisation
2533		2585
2534	struct myclass	2586	struct myclass
2535	{	2587	{
2536	void io_cb (ev::io &w, int revents) { }	2588	void io_cb (ev::io &w, int revents) { }
2537	}	2589	}
2538		2590
2539	myclass obj;	2591	myclass obj;
2540	ev::io iow;	2592	ev::io iow;
2541	iow.set <myclass, &myclass::io_cb> (&obj);	2593	iow.set <myclass, &myclass::io_cb> (&obj);
2542		2594
2543	=item w->set<function> (void *data = 0)	2595	=item w->set<function> (void *data = 0)
2544		2596
2545	Also sets a callback, but uses a static method or plain function as	2597	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	2598	callback. The optional C<data> argument will be stored in the watcher's
…		…
2550		2602
2551	See the method-C<set> above for more details.	2603	See the method-C<set> above for more details.
2552		2604
2553	Example:	2605	Example:
2554		2606
2555	static void io_cb (ev::io &w, int revents) { }	2607	static void io_cb (ev::io &w, int revents) { }
2556	iow.set <io_cb> ();	2608	iow.set <io_cb> ();
2557		2609
2558	=item w->set (struct ev_loop *)	2610	=item w->set (struct ev_loop *)
2559		2611
2560	Associates a different C<struct ev_loop> with this watcher. You can only	2612	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).	2613	do this when the watcher is inactive (and not pending either).
…		…
2594	=back	2646	=back
2595		2647
2596	Example: Define a class with an IO and idle watcher, start one of them in	2648	Example: Define a class with an IO and idle watcher, start one of them in
2597	the constructor.	2649	the constructor.
2598		2650
2599	class myclass	2651	class myclass
2600	{	2652	{
2601	ev::io io; void io_cb (ev::io &w, int revents);	2653	ev::io io; void io_cb (ev::io &w, int revents);
2602	ev:idle idle void idle_cb (ev::idle &w, int revents);	2654	ev:idle idle void idle_cb (ev::idle &w, int revents);
2603		2655
2604	myclass (int fd)	2656	myclass (int fd)
2605	{	2657	{
2606	io .set <myclass, &myclass::io_cb > (this);	2658	io .set <myclass, &myclass::io_cb > (this);
2607	idle.set <myclass, &myclass::idle_cb> (this);	2659	idle.set <myclass, &myclass::idle_cb> (this);
2608		2660
2609	io.start (fd, ev::READ);	2661	io.start (fd, ev::READ);
2610	}	2662	}
2611	};	2663	};
2612		2664
2613		2665
2614	=head1 OTHER LANGUAGE BINDINGS	2666	=head1 OTHER LANGUAGE BINDINGS
2615		2667
2616	Libev does not offer other language bindings itself, but bindings for a	2668	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,	2678	libev. EV is developed together with libev. Apart from the EV core module,
2627	there are additional modules that implement libev-compatible interfaces	2679	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	2680	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>).	2681	C<libglib> event core (C<Glib::EV> and C<EV::Glib>).
2630		2682
2631	It can be found and installed via CPAN, its homepage is found at	2683	It can be found and installed via CPAN, its homepage is at
2632	L<http://software.schmorp.de/pkg/EV>.	2684	L<http://software.schmorp.de/pkg/EV>.
		2685
		2686	=item Python
		2687
		2688	Python bindings can be found at L<http://code.google.com/p/pyev/>. It
		2689	seems to be quite complete and well-documented. Note, however, that the
		2690	patch they require for libev is outright dangerous as it breaks the ABI
		2691	for everybody else, and therefore, should never be applied in an installed
		2692	libev (if python requires an incompatible ABI then it needs to embed
		2693	libev).
2633		2694
2634	=item Ruby	2695	=item Ruby
2635		2696
2636	Tony Arcieri has written a ruby extension that offers access to a subset	2697	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	2698	of the libev API and adds file handle abstractions, asynchronous DNS and
…		…
2639	L<http://rev.rubyforge.org/>.	2700	L<http://rev.rubyforge.org/>.
2640		2701
2641	=item D	2702	=item D
2642		2703
2643	Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to	2704	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>.	2705	be found at L<http://proj.llucax.com.ar/wiki/evd>.
2645		2706
2646	=back	2707	=back
2647		2708
2648		2709
2649	=head1 MACRO MAGIC	2710	=head1 MACRO MAGIC
…		…
2661		2722
2662	This provides the loop I<argument> for functions, if one is required ("ev	2723	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,	2724	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:	2725	C<EV_A_> is used when other arguments are following. Example:
2665		2726
2666	ev_unref (EV_A);	2727	ev_unref (EV_A);
2667	ev_timer_add (EV_A_ watcher);	2728	ev_timer_add (EV_A_ watcher);
2668	ev_loop (EV_A_ 0);	2729	ev_loop (EV_A_ 0);
2669		2730
2670	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	2731	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
2671	which is often provided by the following macro.	2732	which is often provided by the following macro.
2672		2733
2673	=item C<EV_P>, C<EV_P_>	2734	=item C<EV_P>, C<EV_P_>
2674		2735
2675	This provides the loop I<parameter> for functions, if one is required ("ev	2736	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,	2737	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:	2738	C<EV_P_> is used when other parameters are following. Example:
2678		2739
2679	// this is how ev_unref is being declared	2740	// this is how ev_unref is being declared
2680	static void ev_unref (EV_P);	2741	static void ev_unref (EV_P);
2681		2742
2682	// this is how you can declare your typical callback	2743	// this is how you can declare your typical callback
2683	static void cb (EV_P_ ev_timer *w, int revents)	2744	static void cb (EV_P_ ev_timer *w, int revents)
2684		2745
2685	It declares a parameter C<loop> of type C<struct ev_loop *>, quite	2746	It declares a parameter C<loop> of type C<struct ev_loop *>, quite
2686	suitable for use with C<EV_A>.	2747	suitable for use with C<EV_A>.
2687		2748
2688	=item C<EV_DEFAULT>, C<EV_DEFAULT_>	2749	=item C<EV_DEFAULT>, C<EV_DEFAULT_>
…		…
2704		2765
2705	Example: Declare and initialise a check watcher, utilising the above	2766	Example: Declare and initialise a check watcher, utilising the above
2706	macros so it will work regardless of whether multiple loops are supported	2767	macros so it will work regardless of whether multiple loops are supported
2707	or not.	2768	or not.
2708		2769
2709	static void	2770	static void
2710	check_cb (EV_P_ ev_timer *w, int revents)	2771	check_cb (EV_P_ ev_timer *w, int revents)
2711	{	2772	{
2712	ev_check_stop (EV_A_ w);	2773	ev_check_stop (EV_A_ w);
2713	}	2774	}
2714		2775
2715	ev_check check;	2776	ev_check check;
2716	ev_check_init (&check, check_cb);	2777	ev_check_init (&check, check_cb);
2717	ev_check_start (EV_DEFAULT_ &check);	2778	ev_check_start (EV_DEFAULT_ &check);
2718	ev_loop (EV_DEFAULT_ 0);	2779	ev_loop (EV_DEFAULT_ 0);
2719		2780
2720	=head1 EMBEDDING	2781	=head1 EMBEDDING
2721		2782
2722	Libev can (and often is) directly embedded into host	2783	Libev can (and often is) directly embedded into host
2723	applications. Examples of applications that embed it include the Deliantra	2784	applications. Examples of applications that embed it include the Deliantra
…		…
2737	=head3 CORE EVENT LOOP	2798	=head3 CORE EVENT LOOP
2738		2799
2739	To include only the libev core (all the C<ev_*> functions), with manual	2800	To include only the libev core (all the C<ev_*> functions), with manual
2740	configuration (no autoconf):	2801	configuration (no autoconf):
2741		2802
2742	#define EV_STANDALONE 1	2803	#define EV_STANDALONE 1
2743	#include "ev.c"	2804	#include "ev.c"
2744		2805
2745	This will automatically include F<ev.h>, too, and should be done in a	2806	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	2807	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	2808	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	2809	done by writing a wrapper around F<ev.h> that you can include instead and
2749	where you can put other configuration options):	2810	where you can put other configuration options):
2750		2811
2751	#define EV_STANDALONE 1	2812	#define EV_STANDALONE 1
2752	#include "ev.h"	2813	#include "ev.h"
2753		2814
2754	Both header files and implementation files can be compiled with a C++	2815	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	2816	compiler (at least, thats a stated goal, and breakage will be treated
2756	as a bug).	2817	as a bug).
2757		2818
2758	You need the following files in your source tree, or in a directory	2819	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):	2820	in your include path (e.g. in libev/ when using -Ilibev):
2760		2821
2761	ev.h	2822	ev.h
2762	ev.c	2823	ev.c
2763	ev_vars.h	2824	ev_vars.h
2764	ev_wrap.h	2825	ev_wrap.h
2765		2826
2766	ev_win32.c required on win32 platforms only	2827	ev_win32.c required on win32 platforms only
2767		2828
2768	ev_select.c only when select backend is enabled (which is enabled by default)	2829	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)	2830	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)	2831	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)	2832	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)	2833	ev_port.c only when the solaris port backend is enabled (disabled by default)
2773		2834
2774	F<ev.c> includes the backend files directly when enabled, so you only need	2835	F<ev.c> includes the backend files directly when enabled, so you only need
2775	to compile this single file.	2836	to compile this single file.
2776		2837
2777	=head3 LIBEVENT COMPATIBILITY API	2838	=head3 LIBEVENT COMPATIBILITY API
2778		2839
2779	To include the libevent compatibility API, also include:	2840	To include the libevent compatibility API, also include:
2780		2841
2781	#include "event.c"	2842	#include "event.c"
2782		2843
2783	in the file including F<ev.c>, and:	2844	in the file including F<ev.c>, and:
2784		2845
2785	#include "event.h"	2846	#include "event.h"
2786		2847
2787	in the files that want to use the libevent API. This also includes F<ev.h>.	2848	in the files that want to use the libevent API. This also includes F<ev.h>.
2788		2849
2789	You need the following additional files for this:	2850	You need the following additional files for this:
2790		2851
2791	event.h	2852	event.h
2792	event.c	2853	event.c
2793		2854
2794	=head3 AUTOCONF SUPPORT	2855	=head3 AUTOCONF SUPPORT
2795		2856
2796	Instead of using C<EV_STANDALONE=1> and providing your configuration in	2857	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	2858	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	2859	F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then
2799	include F<config.h> and configure itself accordingly.	2860	include F<config.h> and configure itself accordingly.
2800		2861
2801	For this of course you need the m4 file:	2862	For this of course you need the m4 file:
2802		2863
2803	libev.m4	2864	libev.m4
2804		2865
2805	=head2 PREPROCESSOR SYMBOLS/MACROS	2866	=head2 PREPROCESSOR SYMBOLS/MACROS
2806		2867
2807	Libev can be configured via a variety of preprocessor symbols you have to	2868	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	2869	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,	3146	members. You have to define it each time you include one of the files,
3086	though, and it must be identical each time.	3147	though, and it must be identical each time.
3087		3148
3088	For example, the perl EV module uses something like this:	3149	For example, the perl EV module uses something like this:
3089		3150
3090	#define EV_COMMON \	3151	#define EV_COMMON \
3091	SV self; / contains this struct */ \	3152	SV self; / contains this struct */ \
3092	SV cb_sv, fh /* note no trailing ";" */	3153	SV cb_sv, fh /* note no trailing ";" */
3093		3154
3094	=item EV_CB_DECLARE (type)	3155	=item EV_CB_DECLARE (type)
3095		3156
3096	=item EV_CB_INVOKE (watcher, revents)	3157	=item EV_CB_INVOKE (watcher, revents)
3097		3158
…		…
3108		3169
3109	If you need to re-export the API (e.g. via a DLL) and you need a list of	3170	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	3171	exported symbols, you can use the provided F<Symbol.*> files which list
3111	all public symbols, one per line:	3172	all public symbols, one per line:
3112		3173
3113	Symbols.ev for libev proper	3174	Symbols.ev for libev proper
3114	Symbols.event for the libevent emulation	3175	Symbols.event for the libevent emulation
3115		3176
3116	This can also be used to rename all public symbols to avoid clashes with	3177	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	3178	multiple versions of libev linked together (which is obviously bad in
3118	itself, but sometimes it is inconvenient to avoid this).	3179	itself, but sometimes it is inconvenient to avoid this).
3119		3180
…		…
3140	file.	3201	file.
3141		3202
3142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	3203	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:	3204	that everybody includes and which overrides some configure choices:
3144		3205
3145	#define EV_MINIMAL 1	3206	#define EV_MINIMAL 1
3146	#define EV_USE_POLL 0	3207	#define EV_USE_POLL 0
3147	#define EV_MULTIPLICITY 0	3208	#define EV_MULTIPLICITY 0
3148	#define EV_PERIODIC_ENABLE 0	3209	#define EV_PERIODIC_ENABLE 0
3149	#define EV_STAT_ENABLE 0	3210	#define EV_STAT_ENABLE 0
3150	#define EV_FORK_ENABLE 0	3211	#define EV_FORK_ENABLE 0
3151	#define EV_CONFIG_H <config.h>	3212	#define EV_CONFIG_H <config.h>
3152	#define EV_MINPRI 0	3213	#define EV_MINPRI 0
3153	#define EV_MAXPRI 0	3214	#define EV_MAXPRI 0
3154		3215
3155	#include "ev++.h"	3216	#include "ev++.h"
3156		3217
3157	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	3218	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3158		3219
3159	#include "ev_cpp.h"	3220	#include "ev_cpp.h"
3160	#include "ev.c"	3221	#include "ev.c"
3161		3222
3162		3223
3163	=head1 THREADS AND COROUTINES	3224	=head1 THREADS AND COROUTINES
3164		3225
3165	=head2 THREADS	3226	=head2 THREADS
…		…
3173	parallel from multiple threads, calls with the same loop parameter must be	3234	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	3235	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	3236	thread ever is inside a call at any point in time, e.g. by using a mutex
3176	per loop).	3237	per loop).
3177		3238
3178	If you want to know which design is best for your problem, then I cannot	3239	If you want to know which design (one loop, locking, or multiple loops
3179	help you but by giving some generic advice:	3240	without or something else still) is best for your problem, then I cannot
		3241	help you. I can give some generic advice however:
3180		3242
3181	=over 4	3243	=over 4
3182		3244
3183	=item * most applications have a main thread: use the default libev loop	3245	=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.	3246	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	3379	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	3380	different implementation for windows, as libev offers the POSIX readiness
3319	notification model, which cannot be implemented efficiently on windows	3381	notification model, which cannot be implemented efficiently on windows
3320	(Microsoft monopoly games).	3382	(Microsoft monopoly games).
3321		3383
		3384	A typical way to use libev under windows is to embed it (see the embedding
		3385	section for details) and use the following F<evwrap.h> header file instead
		3386	of F<ev.h>:
		3387
		3388	#define EV_STANDALONE /* keeps ev from requiring config.h */
		3389	#define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
		3390
		3391	#include "ev.h"
		3392
		3393	And compile the following F<evwrap.c> file into your project (make sure
		3394	you do I<not> compile the F<ev.c> or any other embedded soruce files!):
		3395
		3396	#include "evwrap.h"
		3397	#include "ev.c"
		3398
3322	=over 4	3399	=over 4
3323		3400
3324	=item The winsocket select function	3401	=item The winsocket select function
3325		3402
3326	The winsocket C<select> function doesn't follow POSIX in that it	3403	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	3404	requires socket I<handles> and not socket I<file descriptors> (it is
3328	also extremely buggy). This makes select very inefficient, and also	3405	also extremely buggy). This makes select very inefficient, and also
3329	requires a mapping from file descriptors to socket handles. See the	3406	requires a mapping from file descriptors to socket handles (the Microsoft
		3407	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	3408	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.	3409	C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.
3332		3410
3333	The configuration for a "naked" win32 using the Microsoft runtime	3411	The configuration for a "naked" win32 using the Microsoft runtime
3334	libraries and raw winsocket select is:	3412	libraries and raw winsocket select is:
3335		3413
3336	#define EV_USE_SELECT 1	3414	#define EV_USE_SELECT 1
3337	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	3415	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
3338		3416
3339	Note that winsockets handling of fd sets is O(n), so you can easily get a	3417	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.	3418	complexity in the O(n²) range when using win32.
3341		3419
3342	=item Limited number of file descriptors	3420	=item Limited number of file descriptors
…		…
3374	In addition to a working ISO-C implementation, libev relies on a few	3452	In addition to a working ISO-C implementation, libev relies on a few
3375	additional extensions:	3453	additional extensions:
3376		3454
3377	=over 4	3455	=over 4
3378		3456
		3457	=item C<void ()(ev_watcher_type , int revents)> must have compatible
		3458	calling conventions regardless of C<ev_watcher_type *>.
		3459
		3460	Libev assumes not only that all watcher pointers have the same internal
		3461	structure (guaranteed by POSIX but not by ISO C for example), but it also
		3462	assumes that the same (machine) code can be used to call any watcher
		3463	callback: The watcher callbacks have different type signatures, but libev
		3464	calls them using an C<ev_watcher *> internally.
		3465
3379	=item C<sig_atomic_t volatile> must be thread-atomic as well	3466	=item C<sig_atomic_t volatile> must be thread-atomic as well
3380		3467
3381	The type C<sig_atomic_t volatile> (or whatever is defined as	3468	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	3469	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	3470	threads. This is not part of the specification for C<sig_atomic_t>, but is

Diff Legend

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

Administered by

schmorpforge-cvs@schmorp.de

Powered by ViewVC 1.2.3