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Revision 1.162 by root, Mon May 26 03:54:40 2008 UTC vs.
Revision 1.173 by root, Thu Aug 7 19:24:56 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
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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
…		…
604		604
605	Here are the gory details of what C<ev_loop> does:	605	Here are the gory details of what C<ev_loop> does:
606		606
607	- Before the first iteration, call any pending watchers.	607	- Before the first iteration, call any pending watchers.
608	* If EVFLAG_FORKCHECK was used, check for a fork.	608	* If EVFLAG_FORKCHECK was used, check for a fork.
609	- If a fork was detected, queue and call all fork watchers.	609	- If a fork was detected (by any means), queue and call all fork watchers.
610	- Queue and call all prepare watchers.	610	- Queue and call all prepare watchers.
611	- If we have been forked, recreate the kernel state.	611	- If we have been forked, detach and recreate the kernel state
		612	as to not disturb the other process.
612	- Update the kernel state with all outstanding changes.	613	- Update the kernel state with all outstanding changes.
613	- Update the "event loop time".	614	- Update the "event loop time" (ev_now ()).
614	- Calculate for how long to sleep or block, if at all	615	- Calculate for how long to sleep or block, if at all
615	(active idle watchers, EVLOOP_NONBLOCK or not having	616	(active idle watchers, EVLOOP_NONBLOCK or not having
616	any active watchers at all will result in not sleeping).	617	any active watchers at all will result in not sleeping).
617	- Sleep if the I/O and timer collect interval say so.	618	- Sleep if the I/O and timer collect interval say so.
618	- Block the process, waiting for any events.	619	- Block the process, waiting for any events.
619	- Queue all outstanding I/O (fd) events.	620	- Queue all outstanding I/O (fd) events.
620	- Update the "event loop time" and do time jump handling.	621	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
621	- Queue all outstanding timers.	622	- Queue all outstanding timers.
622	- Queue all outstanding periodics.	623	- Queue all outstanding periodics.
623	- If no events are pending now, queue all idle watchers.	624	- Unless any events are pending now, queue all idle watchers.
624	- Queue all check watchers.	625	- Queue all check watchers.
625	- Call all queued watchers in reverse order (i.e. check watchers first).	626	- 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	627	Signals and child watchers are implemented as I/O watchers, and will
627	be handled here by queueing them when their watcher gets executed.	628	be handled here by queueing them when their watcher gets executed.
628	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	629	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
…		…
633	anymore.	634	anymore.
634		635
635	... queue jobs here, make sure they register event watchers as long	636	... 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..)	637	... as they still have work to do (even an idle watcher will do..)
637	ev_loop (my_loop, 0);	638	ev_loop (my_loop, 0);
638	... jobs done. yeah!	639	... jobs done or somebody called unloop. yeah!
639		640
640	=item ev_unloop (loop, how)	641	=item ev_unloop (loop, how)
641		642
642	Can be used to make a call to C<ev_loop> return early (but only after it	643	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	644	has processed all outstanding events). The C<how> argument must be either
…		…
664	respectively).	665	respectively).
665		666
666	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	667	Example: Create a signal watcher, but keep it from keeping C<ev_loop>
667	running when nothing else is active.	668	running when nothing else is active.
668		669
669	struct ev_signal exitsig;	670	struct ev_signal exitsig;
670	ev_signal_init (&exitsig, sig_cb, SIGINT);	671	ev_signal_init (&exitsig, sig_cb, SIGINT);
671	ev_signal_start (loop, &exitsig);	672	ev_signal_start (loop, &exitsig);
672	evf_unref (loop);	673	evf_unref (loop);
673		674
674	Example: For some weird reason, unregister the above signal handler again.	675	Example: For some weird reason, unregister the above signal handler again.
675		676
676	ev_ref (loop);	677	ev_ref (loop);
677	ev_signal_stop (loop, &exitsig);	678	ev_signal_stop (loop, &exitsig);
678		679
679	=item ev_set_io_collect_interval (loop, ev_tstamp interval)	680	=item ev_set_io_collect_interval (loop, ev_tstamp interval)
680		681
681	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)	682	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
682		683
683	These advanced functions influence the time that libev will spend waiting	684	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	685	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.	686	will try to invoke timer/periodic callbacks and I/O callbacks with minimum
		687	latency.
686		688
687	Setting these to a higher value (the C<interval> I<must> be >= C<0>)	689	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	690	allows libev to delay invocation of I/O and timer/periodic callbacks
689	increase efficiency of loop iterations.	691	to increase efficiency of loop iterations (or to increase power-saving
		692	opportunities).
690		693
691	The background is that sometimes your program runs just fast enough to	694	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	695	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	696	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	697	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	713	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	714	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>,	715	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.	716	as this approaches the timing granularity of most systems.
714		717
		718	Setting the I<timeout collect interval> can improve the opportunity for
		719	saving power, as the program will "bundle" timer callback invocations that
		720	are "near" in time together, by delaying some, thus reducing the number of
		721	times the process sleeps and wakes up again. Another useful technique to
		722	reduce iterations/wake-ups is to use C<ev_periodic> watchers and make sure
		723	they fire on, say, one-second boundaries only.
		724
715	=item ev_loop_verify (loop)	725	=item ev_loop_verify (loop)
716		726
717	This function only does something when C<EV_VERIFY> support has been	727	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	728	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	729	them for validity. If anything is found to be inconsistent, it will print
…		…
730		740
731	A watcher is a structure that you create and register to record your	741	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	742	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:	743	become readable, you would create an C<ev_io> watcher for that:
734		744
735	static void my_cb (struct ev_loop loop, struct ev_io w, int revents)	745	static void my_cb (struct ev_loop loop, struct ev_io w, int revents)
736	{	746	{
737	ev_io_stop (w);	747	ev_io_stop (w);
738	ev_unloop (loop, EVUNLOOP_ALL);	748	ev_unloop (loop, EVUNLOOP_ALL);
739	}	749	}
740		750
741	struct ev_loop *loop = ev_default_loop (0);	751	struct ev_loop *loop = ev_default_loop (0);
742	struct ev_io stdin_watcher;	752	struct ev_io stdin_watcher;
743	ev_init (&stdin_watcher, my_cb);	753	ev_init (&stdin_watcher, my_cb);
744	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	754	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
745	ev_io_start (loop, &stdin_watcher);	755	ev_io_start (loop, &stdin_watcher);
746	ev_loop (loop, 0);	756	ev_loop (loop, 0);
747		757
748	As you can see, you are responsible for allocating the memory for your	758	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,	759	watcher structures (and it is usually a bad idea to do this on the stack,
750	although this can sometimes be quite valid).	760	although this can sometimes be quite valid).
751		761
…		…
978	to associate arbitrary data with your watcher. If you need more data and	988	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	989	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	990	member, you can also "subclass" the watcher type and provide your own
981	data:	991	data:
982		992
983	struct my_io	993	struct my_io
984	{	994	{
985	struct ev_io io;	995	struct ev_io io;
986	int otherfd;	996	int otherfd;
987	void *somedata;	997	void *somedata;
988	struct whatever *mostinteresting;	998	struct whatever *mostinteresting;
989	}	999	}
990		1000
991	And since your callback will be called with a pointer to the watcher, you	1001	And since your callback will be called with a pointer to the watcher, you
992	can cast it back to your own type:	1002	can cast it back to your own type:
993		1003
994	static void my_cb (struct ev_loop loop, struct ev_io w_, int revents)	1004	static void my_cb (struct ev_loop loop, struct ev_io w_, int revents)
995	{	1005	{
996	struct my_io w = (struct my_io )w_;	1006	struct my_io w = (struct my_io )w_;
997	...	1007	...
998	}	1008	}
999		1009
1000	More interesting and less C-conformant ways of casting your callback type	1010	More interesting and less C-conformant ways of casting your callback type
1001	instead have been omitted.	1011	instead have been omitted.
1002		1012
1003	Another common scenario is having some data structure with multiple	1013	Another common scenario is having some data structure with multiple
1004	watchers:	1014	watchers:
1005		1015
1006	struct my_biggy	1016	struct my_biggy
1007	{	1017	{
1008	int some_data;	1018	int some_data;
1009	ev_timer t1;	1019	ev_timer t1;
1010	ev_timer t2;	1020	ev_timer t2;
1011	}	1021	}
1012		1022
1013	In this case getting the pointer to C<my_biggy> is a bit more complicated,	1023	In this case getting the pointer to C<my_biggy> is a bit more complicated,
1014	you need to use C<offsetof>:	1024	you need to use C<offsetof>:
1015		1025
1016	#include <stddef.h>	1026	#include <stddef.h>
1017		1027
1018	static void	1028	static void
1019	t1_cb (EV_P_ struct ev_timer *w, int revents)	1029	t1_cb (EV_P_ struct ev_timer *w, int revents)
1020	{	1030	{
1021	struct my_biggy big = (struct my_biggy *	1031	struct my_biggy big = (struct my_biggy *
1022	(((char *)w) - offsetof (struct my_biggy, t1));	1032	(((char *)w) - offsetof (struct my_biggy, t1));
1023	}	1033	}
1024		1034
1025	static void	1035	static void
1026	t2_cb (EV_P_ struct ev_timer *w, int revents)	1036	t2_cb (EV_P_ struct ev_timer *w, int revents)
1027	{	1037	{
1028	struct my_biggy big = (struct my_biggy *	1038	struct my_biggy big = (struct my_biggy *
1029	(((char *)w) - offsetof (struct my_biggy, t2));	1039	(((char *)w) - offsetof (struct my_biggy, t2));
1030	}	1040	}
1031		1041
1032		1042
1033	=head1 WATCHER TYPES	1043	=head1 WATCHER TYPES
1034		1044
1035	This section describes each watcher in detail, but will not repeat	1045	This section describes each watcher in detail, but will not repeat
…		…
1162		1172
1163	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well	1173	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	1174	readable, but only once. Since it is likely line-buffered, you could
1165	attempt to read a whole line in the callback.	1175	attempt to read a whole line in the callback.
1166		1176
1167	static void	1177	static void
1168	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	1178	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
1169	{	1179	{
1170	ev_io_stop (loop, w);	1180	ev_io_stop (loop, w);
1171	.. read from stdin here (or from w->fd) and haqndle any I/O errors	1181	.. read from stdin here (or from w->fd) and haqndle any I/O errors
1172	}	1182	}
1173		1183
1174	...	1184	...
1175	struct ev_loop *loop = ev_default_init (0);	1185	struct ev_loop *loop = ev_default_init (0);
1176	struct ev_io stdin_readable;	1186	struct ev_io stdin_readable;
1177	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1187	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1178	ev_io_start (loop, &stdin_readable);	1188	ev_io_start (loop, &stdin_readable);
1179	ev_loop (loop, 0);	1189	ev_loop (loop, 0);
1180		1190
1181		1191
1182	=head2 C<ev_timer> - relative and optionally repeating timeouts	1192	=head2 C<ev_timer> - relative and optionally repeating timeouts
1183		1193
1184	Timer watchers are simple relative timers that generate an event after a	1194	Timer watchers are simple relative timers that generate an event after a
…		…
1269		1279
1270	=head3 Examples	1280	=head3 Examples
1271		1281
1272	Example: Create a timer that fires after 60 seconds.	1282	Example: Create a timer that fires after 60 seconds.
1273		1283
1274	static void	1284	static void
1275	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1285	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
1276	{	1286	{
1277	.. one minute over, w is actually stopped right here	1287	.. one minute over, w is actually stopped right here
1278	}	1288	}
1279		1289
1280	struct ev_timer mytimer;	1290	struct ev_timer mytimer;
1281	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1291	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1282	ev_timer_start (loop, &mytimer);	1292	ev_timer_start (loop, &mytimer);
1283		1293
1284	Example: Create a timeout timer that times out after 10 seconds of	1294	Example: Create a timeout timer that times out after 10 seconds of
1285	inactivity.	1295	inactivity.
1286		1296
1287	static void	1297	static void
1288	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1298	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
1289	{	1299	{
1290	.. ten seconds without any activity	1300	.. ten seconds without any activity
1291	}	1301	}
1292		1302
1293	struct ev_timer mytimer;	1303	struct ev_timer mytimer;
1294	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	1304	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1295	ev_timer_again (&mytimer); /* start timer */	1305	ev_timer_again (&mytimer); /* start timer */
1296	ev_loop (loop, 0);	1306	ev_loop (loop, 0);
1297		1307
1298	// and in some piece of code that gets executed on any "activity":	1308	// and in some piece of code that gets executed on any "activity":
1299	// reset the timeout to start ticking again at 10 seconds	1309	// reset the timeout to start ticking again at 10 seconds
1300	ev_timer_again (&mytimer);	1310	ev_timer_again (&mytimer);
1301		1311
1302		1312
1303	=head2 C<ev_periodic> - to cron or not to cron?	1313	=head2 C<ev_periodic> - to cron or not to cron?
1304		1314
1305	Periodic watchers are also timers of a kind, but they are very versatile	1315	Periodic watchers are also timers of a kind, but they are very versatile
…		…
1448		1458
1449	Example: Call a callback every hour, or, more precisely, whenever the	1459	Example: Call a callback every hour, or, more precisely, whenever the
1450	system clock is divisible by 3600. The callback invocation times have	1460	system clock is divisible by 3600. The callback invocation times have
1451	potentially a lot of jitter, but good long-term stability.	1461	potentially a lot of jitter, but good long-term stability.
1452		1462
1453	static void	1463	static void
1454	clock_cb (struct ev_loop loop, struct ev_io w, int revents)	1464	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
1455	{	1465	{
1456	... its now a full hour (UTC, or TAI or whatever your clock follows)	1466	... its now a full hour (UTC, or TAI or whatever your clock follows)
1457	}	1467	}
1458		1468
1459	struct ev_periodic hourly_tick;	1469	struct ev_periodic hourly_tick;
1460	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1470	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1461	ev_periodic_start (loop, &hourly_tick);	1471	ev_periodic_start (loop, &hourly_tick);
1462		1472
1463	Example: The same as above, but use a reschedule callback to do it:	1473	Example: The same as above, but use a reschedule callback to do it:
1464		1474
1465	#include <math.h>	1475	#include <math.h>
1466		1476
1467	static ev_tstamp	1477	static ev_tstamp
1468	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1478	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1469	{	1479	{
1470	return fmod (now, 3600.) + 3600.;	1480	return fmod (now, 3600.) + 3600.;
1471	}	1481	}
1472		1482
1473	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1483	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1474		1484
1475	Example: Call a callback every hour, starting now:	1485	Example: Call a callback every hour, starting now:
1476		1486
1477	struct ev_periodic hourly_tick;	1487	struct ev_periodic hourly_tick;
1478	ev_periodic_init (&hourly_tick, clock_cb,	1488	ev_periodic_init (&hourly_tick, clock_cb,
1479	fmod (ev_now (loop), 3600.), 3600., 0);	1489	fmod (ev_now (loop), 3600.), 3600., 0);
1480	ev_periodic_start (loop, &hourly_tick);	1490	ev_periodic_start (loop, &hourly_tick);
1481		1491
1482		1492
1483	=head2 C<ev_signal> - signal me when a signal gets signalled!	1493	=head2 C<ev_signal> - signal me when a signal gets signalled!
1484		1494
1485	Signal watchers will trigger an event when the process receives a specific	1495	Signal watchers will trigger an event when the process receives a specific
…		…
1519		1529
1520	=head3 Examples	1530	=head3 Examples
1521		1531
1522	Example: Try to exit cleanly on SIGINT and SIGTERM.	1532	Example: Try to exit cleanly on SIGINT and SIGTERM.
1523		1533
1524	static void	1534	static void
1525	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1535	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1526	{	1536	{
1527	ev_unloop (loop, EVUNLOOP_ALL);	1537	ev_unloop (loop, EVUNLOOP_ALL);
1528	}	1538	}
1529		1539
1530	struct ev_signal signal_watcher;	1540	struct ev_signal signal_watcher;
1531	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1541	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1532	ev_signal_start (loop, &sigint_cb);	1542	ev_signal_start (loop, &sigint_cb);
1533		1543
1534		1544
1535	=head2 C<ev_child> - watch out for process status changes	1545	=head2 C<ev_child> - watch out for process status changes
1536		1546
1537	Child watchers trigger when your process receives a SIGCHLD in response to	1547	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	1569	handler, you can override it easily by installing your own handler for
1560	C<SIGCHLD> after initialising the default loop, and making sure the	1570	C<SIGCHLD> after initialising the default loop, and making sure the
1561	default loop never gets destroyed. You are encouraged, however, to use an	1571	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	1572	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.	1573	that, so other libev users can use C<ev_child> watchers freely.
		1574
		1575	=head3 Stopping the Child Watcher
		1576
		1577	Currently, the child watcher never gets stopped, even when the
		1578	child terminates, so normally one needs to stop the watcher in the
		1579	callback. Future versions of libev might stop the watcher automatically
		1580	when a child exit is detected.
1564		1581
1565	=head3 Watcher-Specific Functions and Data Members	1582	=head3 Watcher-Specific Functions and Data Members
1566		1583
1567	=over 4	1584	=over 4
1568		1585
…		…
1597	=head3 Examples	1614	=head3 Examples
1598		1615
1599	Example: C<fork()> a new process and install a child handler to wait for	1616	Example: C<fork()> a new process and install a child handler to wait for
1600	its completion.	1617	its completion.
1601		1618
1602	ev_child cw;	1619	ev_child cw;
1603		1620
1604	static void	1621	static void
1605	child_cb (EV_P_ struct ev_child *w, int revents)	1622	child_cb (EV_P_ struct ev_child *w, int revents)
1606	{	1623	{
1607	ev_child_stop (EV_A_ w);	1624	ev_child_stop (EV_A_ w);
1608	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);	1625	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
1609	}	1626	}
1610		1627
1611	pid_t pid = fork ();	1628	pid_t pid = fork ();
1612		1629
1613	if (pid < 0)	1630	if (pid < 0)
1614	// error	1631	// error
1615	else if (pid == 0)	1632	else if (pid == 0)
1616	{	1633	{
1617	// the forked child executes here	1634	// the forked child executes here
1618	exit (1);	1635	exit (1);
1619	}	1636	}
1620	else	1637	else
1621	{	1638	{
1622	ev_child_init (&cw, child_cb, pid, 0);	1639	ev_child_init (&cw, child_cb, pid, 0);
1623	ev_child_start (EV_DEFAULT_ &cw);	1640	ev_child_start (EV_DEFAULT_ &cw);
1624	}	1641	}
1625		1642
1626		1643
1627	=head2 C<ev_stat> - did the file attributes just change?	1644	=head2 C<ev_stat> - did the file attributes just change?
1628		1645
1629	This watches a file system path for attribute changes. That is, it calls	1646	This watches a file system path for attribute changes. That is, it calls
…		…
1662	will be no polling.	1679	will be no polling.
1663		1680
1664	=head3 ABI Issues (Largefile Support)	1681	=head3 ABI Issues (Largefile Support)
1665		1682
1666	Libev by default (unless the user overrides this) uses the default	1683	Libev by default (unless the user overrides this) uses the default
1667	compilation environment, which means that on systems with optionally	1684	compilation environment, which means that on systems with large file
1668	disabled large file support, you get the 32 bit version of the stat	1685	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	1686	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	1687	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	1688	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	1689	obviously the case with any flags that change the ABI, but the problem is
1673	most noticeably with ev_stat and large file support.	1690	most noticeably disabled with ev_stat and large file support.
		1691
		1692	The solution for this is to lobby your distribution maker to make large
		1693	file interfaces available by default (as e.g. FreeBSD does) and not
		1694	optional. Libev cannot simply switch on large file support because it has
		1695	to exchange stat structures with application programs compiled using the
		1696	default compilation environment.
1674		1697
1675	=head3 Inotify	1698	=head3 Inotify
1676		1699
1677	When C<inotify (7)> support has been compiled into libev (generally only	1700	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	1701	available on Linux) and present at runtime, it will be used to speed up
…		…
1767		1790
1768	=head3 Examples	1791	=head3 Examples
1769		1792
1770	Example: Watch C</etc/passwd> for attribute changes.	1793	Example: Watch C</etc/passwd> for attribute changes.
1771		1794
1772	static void	1795	static void
1773	passwd_cb (struct ev_loop loop, ev_stat w, int revents)	1796	passwd_cb (struct ev_loop loop, ev_stat w, int revents)
1774	{	1797	{
1775	/* /etc/passwd changed in some way */	1798	/* /etc/passwd changed in some way */
1776	if (w->attr.st_nlink)	1799	if (w->attr.st_nlink)
1777	{	1800	{
1778	printf ("passwd current size %ld\n", (long)w->attr.st_size);	1801	printf ("passwd current size %ld\n", (long)w->attr.st_size);
1779	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);	1802	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
1780	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);	1803	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
1781	}	1804	}
1782	else	1805	else
1783	/* you shalt not abuse printf for puts */	1806	/* you shalt not abuse printf for puts */
1784	puts ("wow, /etc/passwd is not there, expect problems. "	1807	puts ("wow, /etc/passwd is not there, expect problems. "
1785	"if this is windows, they already arrived\n");	1808	"if this is windows, they already arrived\n");
1786	}	1809	}
1787		1810
1788	...	1811	...
1789	ev_stat passwd;	1812	ev_stat passwd;
1790		1813
1791	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);	1814	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
1792	ev_stat_start (loop, &passwd);	1815	ev_stat_start (loop, &passwd);
1793		1816
1794	Example: Like above, but additionally use a one-second delay so we do not	1817	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	1818	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	1819	one might do the work both on C<ev_stat> callback invocation I<and> on
1797	C<ev_timer> callback invocation).	1820	C<ev_timer> callback invocation).
1798		1821
1799	static ev_stat passwd;	1822	static ev_stat passwd;
1800	static ev_timer timer;	1823	static ev_timer timer;
1801		1824
1802	static void	1825	static void
1803	timer_cb (EV_P_ ev_timer *w, int revents)	1826	timer_cb (EV_P_ ev_timer *w, int revents)
1804	{	1827	{
1805	ev_timer_stop (EV_A_ w);	1828	ev_timer_stop (EV_A_ w);
1806		1829
1807	/* now it's one second after the most recent passwd change */	1830	/* now it's one second after the most recent passwd change */
1808	}	1831	}
1809		1832
1810	static void	1833	static void
1811	stat_cb (EV_P_ ev_stat *w, int revents)	1834	stat_cb (EV_P_ ev_stat *w, int revents)
1812	{	1835	{
1813	/* reset the one-second timer */	1836	/* reset the one-second timer */
1814	ev_timer_again (EV_A_ &timer);	1837	ev_timer_again (EV_A_ &timer);
1815	}	1838	}
1816		1839
1817	...	1840	...
1818	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);	1841	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
1819	ev_stat_start (loop, &passwd);	1842	ev_stat_start (loop, &passwd);
1820	ev_timer_init (&timer, timer_cb, 0., 1.02);	1843	ev_timer_init (&timer, timer_cb, 0., 1.02);
1821		1844
1822		1845
1823	=head2 C<ev_idle> - when you've got nothing better to do...	1846	=head2 C<ev_idle> - when you've got nothing better to do...
1824		1847
1825	Idle watchers trigger events when no other events of the same or higher	1848	Idle watchers trigger events when no other events of the same or higher
…		…
1856	=head3 Examples	1879	=head3 Examples
1857		1880
1858	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the	1881	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1859	callback, free it. Also, use no error checking, as usual.	1882	callback, free it. Also, use no error checking, as usual.
1860		1883
1861	static void	1884	static void
1862	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1885	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1863	{	1886	{
1864	free (w);	1887	free (w);
1865	// now do something you wanted to do when the program has	1888	// now do something you wanted to do when the program has
1866	// no longer anything immediate to do.	1889	// no longer anything immediate to do.
1867	}	1890	}
1868		1891
1869	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1892	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1870	ev_idle_init (idle_watcher, idle_cb);	1893	ev_idle_init (idle_watcher, idle_cb);
1871	ev_idle_start (loop, idle_cb);	1894	ev_idle_start (loop, idle_cb);
1872		1895
1873		1896
1874	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!	1897	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
1875		1898
1876	Prepare and check watchers are usually (but not always) used in tandem:	1899	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	1971	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	1972	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	1973	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.	1974	the callbacks for the IO/timeout watchers might not have been called yet.
1952		1975
1953	static ev_io iow [nfd];	1976	static ev_io iow [nfd];
1954	static ev_timer tw;	1977	static ev_timer tw;
1955		1978
1956	static void	1979	static void
1957	io_cb (ev_loop loop, ev_io w, int revents)	1980	io_cb (ev_loop loop, ev_io w, int revents)
1958	{	1981	{
1959	}	1982	}
1960		1983
1961	// create io watchers for each fd and a timer before blocking	1984	// create io watchers for each fd and a timer before blocking
1962	static void	1985	static void
1963	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1986	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1964	{	1987	{
1965	int timeout = 3600000;	1988	int timeout = 3600000;
1966	struct pollfd fds [nfd];	1989	struct pollfd fds [nfd];
1967	// actual code will need to loop here and realloc etc.	1990	// actual code will need to loop here and realloc etc.
1968	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1991	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1969		1992
1970	/* the callback is illegal, but won't be called as we stop during check */	1993	/* the callback is illegal, but won't be called as we stop during check */
1971	ev_timer_init (&tw, 0, timeout * 1e-3);	1994	ev_timer_init (&tw, 0, timeout * 1e-3);
1972	ev_timer_start (loop, &tw);	1995	ev_timer_start (loop, &tw);
1973		1996
1974	// create one ev_io per pollfd	1997	// create one ev_io per pollfd
1975	for (int i = 0; i < nfd; ++i)	1998	for (int i = 0; i < nfd; ++i)
1976	{	1999	{
1977	ev_io_init (iow + i, io_cb, fds [i].fd,	2000	ev_io_init (iow + i, io_cb, fds [i].fd,
1978	((fds [i].events & POLLIN ? EV_READ : 0)	2001	((fds [i].events & POLLIN ? EV_READ : 0)
1979	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	2002	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1980		2003
1981	fds [i].revents = 0;	2004	fds [i].revents = 0;
1982	ev_io_start (loop, iow + i);	2005	ev_io_start (loop, iow + i);
1983	}	2006	}
1984	}	2007	}
1985		2008
1986	// stop all watchers after blocking	2009	// stop all watchers after blocking
1987	static void	2010	static void
1988	adns_check_cb (ev_loop loop, ev_check w, int revents)	2011	adns_check_cb (ev_loop loop, ev_check w, int revents)
1989	{	2012	{
1990	ev_timer_stop (loop, &tw);	2013	ev_timer_stop (loop, &tw);
1991		2014
1992	for (int i = 0; i < nfd; ++i)	2015	for (int i = 0; i < nfd; ++i)
1993	{	2016	{
1994	// set the relevant poll flags	2017	// set the relevant poll flags
1995	// could also call adns_processreadable etc. here	2018	// could also call adns_processreadable etc. here
1996	struct pollfd *fd = fds + i;	2019	struct pollfd *fd = fds + i;
1997	int revents = ev_clear_pending (iow + i);	2020	int revents = ev_clear_pending (iow + i);
1998	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;	2021	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1999	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;	2022	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
2000		2023
2001	// now stop the watcher	2024	// now stop the watcher
2002	ev_io_stop (loop, iow + i);	2025	ev_io_stop (loop, iow + i);
2003	}	2026	}
2004		2027
2005	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	2028	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
2006	}	2029	}
2007		2030
2008	Method 2: This would be just like method 1, but you run C<adns_afterpoll>	2031	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.	2032	in the prepare watcher and would dispose of the check watcher.
2010		2033
2011	Method 3: If the module to be embedded supports explicit event	2034	Method 3: If the module to be embedded supports explicit event
2012	notification (libadns does), you can also make use of the actual watcher	2035	notification (libadns does), you can also make use of the actual watcher
2013	callbacks, and only destroy/create the watchers in the prepare watcher.	2036	callbacks, and only destroy/create the watchers in the prepare watcher.
2014		2037
2015	static void	2038	static void
2016	timer_cb (EV_P_ ev_timer *w, int revents)	2039	timer_cb (EV_P_ ev_timer *w, int revents)
2017	{	2040	{
2018	adns_state ads = (adns_state)w->data;	2041	adns_state ads = (adns_state)w->data;
2019	update_now (EV_A);	2042	update_now (EV_A);
2020		2043
2021	adns_processtimeouts (ads, &tv_now);	2044	adns_processtimeouts (ads, &tv_now);
2022	}	2045	}
2023		2046
2024	static void	2047	static void
2025	io_cb (EV_P_ ev_io *w, int revents)	2048	io_cb (EV_P_ ev_io *w, int revents)
2026	{	2049	{
2027	adns_state ads = (adns_state)w->data;	2050	adns_state ads = (adns_state)w->data;
2028	update_now (EV_A);	2051	update_now (EV_A);
2029		2052
2030	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);	2053	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
2031	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);	2054	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
2032	}	2055	}
2033		2056
2034	// do not ever call adns_afterpoll	2057	// do not ever call adns_afterpoll
2035		2058
2036	Method 4: Do not use a prepare or check watcher because the module you	2059	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	2060	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	2061	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	2062	loop is now no longer controllable by EV. The C<Glib::EV> module does
2040	this.	2063	this.
2041		2064
2042	static gint	2065	static gint
2043	event_poll_func (GPollFD *fds, guint nfds, gint timeout)	2066	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
2044	{	2067	{
2045	int got_events = 0;	2068	int got_events = 0;
2046		2069
2047	for (n = 0; n < nfds; ++n)	2070	for (n = 0; n < nfds; ++n)
2048	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events	2071	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
2049		2072
2050	if (timeout >= 0)	2073	if (timeout >= 0)
2051	// create/start timer	2074	// create/start timer
2052		2075
2053	// poll	2076	// poll
2054	ev_loop (EV_A_ 0);	2077	ev_loop (EV_A_ 0);
2055		2078
2056	// stop timer again	2079	// stop timer again
2057	if (timeout >= 0)	2080	if (timeout >= 0)
2058	ev_timer_stop (EV_A_ &to);	2081	ev_timer_stop (EV_A_ &to);
2059		2082
2060	// stop io watchers again - their callbacks should have set	2083	// stop io watchers again - their callbacks should have set
2061	for (n = 0; n < nfds; ++n)	2084	for (n = 0; n < nfds; ++n)
2062	ev_io_stop (EV_A_ iow [n]);	2085	ev_io_stop (EV_A_ iow [n]);
2063		2086
2064	return got_events;	2087	return got_events;
2065	}	2088	}
2066		2089
2067		2090
2068	=head2 C<ev_embed> - when one backend isn't enough...	2091	=head2 C<ev_embed> - when one backend isn't enough...
2069		2092
2070	This is a rather advanced watcher type that lets you embed one event loop	2093	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	2171	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	2172	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	2173	C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
2151	used).	2174	used).
2152		2175
2153	struct ev_loop *loop_hi = ev_default_init (0);	2176	struct ev_loop *loop_hi = ev_default_init (0);
2154	struct ev_loop *loop_lo = 0;	2177	struct ev_loop *loop_lo = 0;
2155	struct ev_embed embed;	2178	struct ev_embed embed;
2156		2179
2157	// see if there is a chance of getting one that works	2180	// see if there is a chance of getting one that works
2158	// (remember that a flags value of 0 means autodetection)	2181	// (remember that a flags value of 0 means autodetection)
2159	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()	2182	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
2160	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())	2183	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
2161	: 0;	2184	: 0;
2162		2185
2163	// if we got one, then embed it, otherwise default to loop_hi	2186	// if we got one, then embed it, otherwise default to loop_hi
2164	if (loop_lo)	2187	if (loop_lo)
2165	{	2188	{
2166	ev_embed_init (&embed, 0, loop_lo);	2189	ev_embed_init (&embed, 0, loop_lo);
2167	ev_embed_start (loop_hi, &embed);	2190	ev_embed_start (loop_hi, &embed);
2168	}	2191	}
2169	else	2192	else
2170	loop_lo = loop_hi;	2193	loop_lo = loop_hi;
2171		2194
2172	Example: Check if kqueue is available but not recommended and create	2195	Example: Check if kqueue is available but not recommended and create
2173	a kqueue backend for use with sockets (which usually work with any	2196	a kqueue backend for use with sockets (which usually work with any
2174	kqueue implementation). Store the kqueue/socket-only event loop in	2197	kqueue implementation). Store the kqueue/socket-only event loop in
2175	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).	2198	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
2176		2199
2177	struct ev_loop *loop = ev_default_init (0);	2200	struct ev_loop *loop = ev_default_init (0);
2178	struct ev_loop *loop_socket = 0;	2201	struct ev_loop *loop_socket = 0;
2179	struct ev_embed embed;	2202	struct ev_embed embed;
2180		2203
2181	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)	2204	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
2182	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))	2205	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
2183	{	2206	{
2184	ev_embed_init (&embed, 0, loop_socket);	2207	ev_embed_init (&embed, 0, loop_socket);
2185	ev_embed_start (loop, &embed);	2208	ev_embed_start (loop, &embed);
2186	}	2209	}
2187		2210
2188	if (!loop_socket)	2211	if (!loop_socket)
2189	loop_socket = loop;	2212	loop_socket = loop;
2190		2213
2191	// now use loop_socket for all sockets, and loop for everything else	2214	// now use loop_socket for all sockets, and loop for everything else
2192		2215
2193		2216
2194	=head2 C<ev_fork> - the audacity to resume the event loop after a fork	2217	=head2 C<ev_fork> - the audacity to resume the event loop after a fork
2195		2218
2196	Fork watchers are called when a C<fork ()> was detected (usually because	2219	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	2408	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	2409	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>	2410	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
2388	value passed to C<ev_once>:	2411	value passed to C<ev_once>:
2389		2412
2390	static void stdin_ready (int revents, void *arg)	2413	static void stdin_ready (int revents, void *arg)
2391	{	2414	{
2392	if (revents & EV_TIMEOUT)	2415	if (revents & EV_TIMEOUT)
2393	/* doh, nothing entered */;	2416	/* doh, nothing entered */;
2394	else if (revents & EV_READ)	2417	else if (revents & EV_READ)
2395	/* stdin might have data for us, joy! */;	2418	/* stdin might have data for us, joy! */;
2396	}	2419	}
2397		2420
2398	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2421	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2399		2422
2400	=item ev_feed_event (ev_loop , watcher , int revents)	2423	=item ev_feed_event (ev_loop , watcher , int revents)
2401		2424
2402	Feeds the given event set into the event loop, as if the specified event	2425	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	2426	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	2475	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.	2476	the callback model to a model using method callbacks on objects.
2454		2477
2455	To use it,	2478	To use it,
2456		2479
2457	#include <ev++.h>	2480	#include <ev++.h>
2458		2481
2459	This automatically includes F<ev.h> and puts all of its definitions (many	2482	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	2483	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	2484	put into the C<ev> namespace. It should support all the same embedding
2462	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.	2485	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
…		…
2529	your compiler is good :), then the method will be fully inlined into the	2552	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.	2553	thunking function, making it as fast as a direct C callback.
2531		2554
2532	Example: simple class declaration and watcher initialisation	2555	Example: simple class declaration and watcher initialisation
2533		2556
2534	struct myclass	2557	struct myclass
2535	{	2558	{
2536	void io_cb (ev::io &w, int revents) { }	2559	void io_cb (ev::io &w, int revents) { }
2537	}	2560	}
2538		2561
2539	myclass obj;	2562	myclass obj;
2540	ev::io iow;	2563	ev::io iow;
2541	iow.set <myclass, &myclass::io_cb> (&obj);	2564	iow.set <myclass, &myclass::io_cb> (&obj);
2542		2565
2543	=item w->set<function> (void *data = 0)	2566	=item w->set<function> (void *data = 0)
2544		2567
2545	Also sets a callback, but uses a static method or plain function as	2568	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	2569	callback. The optional C<data> argument will be stored in the watcher's
…		…
2550		2573
2551	See the method-C<set> above for more details.	2574	See the method-C<set> above for more details.
2552		2575
2553	Example:	2576	Example:
2554		2577
2555	static void io_cb (ev::io &w, int revents) { }	2578	static void io_cb (ev::io &w, int revents) { }
2556	iow.set <io_cb> ();	2579	iow.set <io_cb> ();
2557		2580
2558	=item w->set (struct ev_loop *)	2581	=item w->set (struct ev_loop *)
2559		2582
2560	Associates a different C<struct ev_loop> with this watcher. You can only	2583	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).	2584	do this when the watcher is inactive (and not pending either).
…		…
2594	=back	2617	=back
2595		2618
2596	Example: Define a class with an IO and idle watcher, start one of them in	2619	Example: Define a class with an IO and idle watcher, start one of them in
2597	the constructor.	2620	the constructor.
2598		2621
2599	class myclass	2622	class myclass
2600	{	2623	{
2601	ev::io io; void io_cb (ev::io &w, int revents);	2624	ev::io io; void io_cb (ev::io &w, int revents);
2602	ev:idle idle void idle_cb (ev::idle &w, int revents);	2625	ev:idle idle void idle_cb (ev::idle &w, int revents);
2603		2626
2604	myclass (int fd)	2627	myclass (int fd)
2605	{	2628	{
2606	io .set <myclass, &myclass::io_cb > (this);	2629	io .set <myclass, &myclass::io_cb > (this);
2607	idle.set <myclass, &myclass::idle_cb> (this);	2630	idle.set <myclass, &myclass::idle_cb> (this);
2608		2631
2609	io.start (fd, ev::READ);	2632	io.start (fd, ev::READ);
2610	}	2633	}
2611	};	2634	};
2612		2635
2613		2636
2614	=head1 OTHER LANGUAGE BINDINGS	2637	=head1 OTHER LANGUAGE BINDINGS
2615		2638
2616	Libev does not offer other language bindings itself, but bindings for a	2639	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,	2649	libev. EV is developed together with libev. Apart from the EV core module,
2627	there are additional modules that implement libev-compatible interfaces	2650	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	2651	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>).	2652	C<libglib> event core (C<Glib::EV> and C<EV::Glib>).
2630		2653
2631	It can be found and installed via CPAN, its homepage is found at	2654	It can be found and installed via CPAN, its homepage is at
2632	L<http://software.schmorp.de/pkg/EV>.	2655	L<http://software.schmorp.de/pkg/EV>.
		2656
		2657	=item Python
		2658
		2659	Python bindings can be found at L<http://code.google.com/p/pyev/>. It
		2660	seems to be quite complete and well-documented. Note, however, that the
		2661	patch they require for libev is outright dangerous as it breaks the ABI
		2662	for everybody else, and therefore, should never be applied in an installed
		2663	libev (if python requires an incompatible ABI then it needs to embed
		2664	libev).
2633		2665
2634	=item Ruby	2666	=item Ruby
2635		2667
2636	Tony Arcieri has written a ruby extension that offers access to a subset	2668	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	2669	of the libev API and adds file handle abstractions, asynchronous DNS and
…		…
2639	L<http://rev.rubyforge.org/>.	2671	L<http://rev.rubyforge.org/>.
2640		2672
2641	=item D	2673	=item D
2642		2674
2643	Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to	2675	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>.	2676	be found at L<http://proj.llucax.com.ar/wiki/evd>.
2645		2677
2646	=back	2678	=back
2647		2679
2648		2680
2649	=head1 MACRO MAGIC	2681	=head1 MACRO MAGIC
…		…
2661		2693
2662	This provides the loop I<argument> for functions, if one is required ("ev	2694	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,	2695	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:	2696	C<EV_A_> is used when other arguments are following. Example:
2665		2697
2666	ev_unref (EV_A);	2698	ev_unref (EV_A);
2667	ev_timer_add (EV_A_ watcher);	2699	ev_timer_add (EV_A_ watcher);
2668	ev_loop (EV_A_ 0);	2700	ev_loop (EV_A_ 0);
2669		2701
2670	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	2702	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
2671	which is often provided by the following macro.	2703	which is often provided by the following macro.
2672		2704
2673	=item C<EV_P>, C<EV_P_>	2705	=item C<EV_P>, C<EV_P_>
2674		2706
2675	This provides the loop I<parameter> for functions, if one is required ("ev	2707	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,	2708	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:	2709	C<EV_P_> is used when other parameters are following. Example:
2678		2710
2679	// this is how ev_unref is being declared	2711	// this is how ev_unref is being declared
2680	static void ev_unref (EV_P);	2712	static void ev_unref (EV_P);
2681		2713
2682	// this is how you can declare your typical callback	2714	// this is how you can declare your typical callback
2683	static void cb (EV_P_ ev_timer *w, int revents)	2715	static void cb (EV_P_ ev_timer *w, int revents)
2684		2716
2685	It declares a parameter C<loop> of type C<struct ev_loop *>, quite	2717	It declares a parameter C<loop> of type C<struct ev_loop *>, quite
2686	suitable for use with C<EV_A>.	2718	suitable for use with C<EV_A>.
2687		2719
2688	=item C<EV_DEFAULT>, C<EV_DEFAULT_>	2720	=item C<EV_DEFAULT>, C<EV_DEFAULT_>
…		…
2704		2736
2705	Example: Declare and initialise a check watcher, utilising the above	2737	Example: Declare and initialise a check watcher, utilising the above
2706	macros so it will work regardless of whether multiple loops are supported	2738	macros so it will work regardless of whether multiple loops are supported
2707	or not.	2739	or not.
2708		2740
2709	static void	2741	static void
2710	check_cb (EV_P_ ev_timer *w, int revents)	2742	check_cb (EV_P_ ev_timer *w, int revents)
2711	{	2743	{
2712	ev_check_stop (EV_A_ w);	2744	ev_check_stop (EV_A_ w);
2713	}	2745	}
2714		2746
2715	ev_check check;	2747	ev_check check;
2716	ev_check_init (&check, check_cb);	2748	ev_check_init (&check, check_cb);
2717	ev_check_start (EV_DEFAULT_ &check);	2749	ev_check_start (EV_DEFAULT_ &check);
2718	ev_loop (EV_DEFAULT_ 0);	2750	ev_loop (EV_DEFAULT_ 0);
2719		2751
2720	=head1 EMBEDDING	2752	=head1 EMBEDDING
2721		2753
2722	Libev can (and often is) directly embedded into host	2754	Libev can (and often is) directly embedded into host
2723	applications. Examples of applications that embed it include the Deliantra	2755	applications. Examples of applications that embed it include the Deliantra
…		…
2737	=head3 CORE EVENT LOOP	2769	=head3 CORE EVENT LOOP
2738		2770
2739	To include only the libev core (all the C<ev_*> functions), with manual	2771	To include only the libev core (all the C<ev_*> functions), with manual
2740	configuration (no autoconf):	2772	configuration (no autoconf):
2741		2773
2742	#define EV_STANDALONE 1	2774	#define EV_STANDALONE 1
2743	#include "ev.c"	2775	#include "ev.c"
2744		2776
2745	This will automatically include F<ev.h>, too, and should be done in a	2777	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	2778	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	2779	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	2780	done by writing a wrapper around F<ev.h> that you can include instead and
2749	where you can put other configuration options):	2781	where you can put other configuration options):
2750		2782
2751	#define EV_STANDALONE 1	2783	#define EV_STANDALONE 1
2752	#include "ev.h"	2784	#include "ev.h"
2753		2785
2754	Both header files and implementation files can be compiled with a C++	2786	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	2787	compiler (at least, thats a stated goal, and breakage will be treated
2756	as a bug).	2788	as a bug).
2757		2789
2758	You need the following files in your source tree, or in a directory	2790	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):	2791	in your include path (e.g. in libev/ when using -Ilibev):
2760		2792
2761	ev.h	2793	ev.h
2762	ev.c	2794	ev.c
2763	ev_vars.h	2795	ev_vars.h
2764	ev_wrap.h	2796	ev_wrap.h
2765		2797
2766	ev_win32.c required on win32 platforms only	2798	ev_win32.c required on win32 platforms only
2767		2799
2768	ev_select.c only when select backend is enabled (which is enabled by default)	2800	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)	2801	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)	2802	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)	2803	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)	2804	ev_port.c only when the solaris port backend is enabled (disabled by default)
2773		2805
2774	F<ev.c> includes the backend files directly when enabled, so you only need	2806	F<ev.c> includes the backend files directly when enabled, so you only need
2775	to compile this single file.	2807	to compile this single file.
2776		2808
2777	=head3 LIBEVENT COMPATIBILITY API	2809	=head3 LIBEVENT COMPATIBILITY API
2778		2810
2779	To include the libevent compatibility API, also include:	2811	To include the libevent compatibility API, also include:
2780		2812
2781	#include "event.c"	2813	#include "event.c"
2782		2814
2783	in the file including F<ev.c>, and:	2815	in the file including F<ev.c>, and:
2784		2816
2785	#include "event.h"	2817	#include "event.h"
2786		2818
2787	in the files that want to use the libevent API. This also includes F<ev.h>.	2819	in the files that want to use the libevent API. This also includes F<ev.h>.
2788		2820
2789	You need the following additional files for this:	2821	You need the following additional files for this:
2790		2822
2791	event.h	2823	event.h
2792	event.c	2824	event.c
2793		2825
2794	=head3 AUTOCONF SUPPORT	2826	=head3 AUTOCONF SUPPORT
2795		2827
2796	Instead of using C<EV_STANDALONE=1> and providing your configuration in	2828	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	2829	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	2830	F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then
2799	include F<config.h> and configure itself accordingly.	2831	include F<config.h> and configure itself accordingly.
2800		2832
2801	For this of course you need the m4 file:	2833	For this of course you need the m4 file:
2802		2834
2803	libev.m4	2835	libev.m4
2804		2836
2805	=head2 PREPROCESSOR SYMBOLS/MACROS	2837	=head2 PREPROCESSOR SYMBOLS/MACROS
2806		2838
2807	Libev can be configured via a variety of preprocessor symbols you have to	2839	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	2840	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,	3117	members. You have to define it each time you include one of the files,
3086	though, and it must be identical each time.	3118	though, and it must be identical each time.
3087		3119
3088	For example, the perl EV module uses something like this:	3120	For example, the perl EV module uses something like this:
3089		3121
3090	#define EV_COMMON \	3122	#define EV_COMMON \
3091	SV self; / contains this struct */ \	3123	SV self; / contains this struct */ \
3092	SV cb_sv, fh /* note no trailing ";" */	3124	SV cb_sv, fh /* note no trailing ";" */
3093		3125
3094	=item EV_CB_DECLARE (type)	3126	=item EV_CB_DECLARE (type)
3095		3127
3096	=item EV_CB_INVOKE (watcher, revents)	3128	=item EV_CB_INVOKE (watcher, revents)
3097		3129
…		…
3108		3140
3109	If you need to re-export the API (e.g. via a DLL) and you need a list of	3141	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	3142	exported symbols, you can use the provided F<Symbol.*> files which list
3111	all public symbols, one per line:	3143	all public symbols, one per line:
3112		3144
3113	Symbols.ev for libev proper	3145	Symbols.ev for libev proper
3114	Symbols.event for the libevent emulation	3146	Symbols.event for the libevent emulation
3115		3147
3116	This can also be used to rename all public symbols to avoid clashes with	3148	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	3149	multiple versions of libev linked together (which is obviously bad in
3118	itself, but sometimes it is inconvenient to avoid this).	3150	itself, but sometimes it is inconvenient to avoid this).
3119		3151
…		…
3140	file.	3172	file.
3141		3173
3142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	3174	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:	3175	that everybody includes and which overrides some configure choices:
3144		3176
3145	#define EV_MINIMAL 1	3177	#define EV_MINIMAL 1
3146	#define EV_USE_POLL 0	3178	#define EV_USE_POLL 0
3147	#define EV_MULTIPLICITY 0	3179	#define EV_MULTIPLICITY 0
3148	#define EV_PERIODIC_ENABLE 0	3180	#define EV_PERIODIC_ENABLE 0
3149	#define EV_STAT_ENABLE 0	3181	#define EV_STAT_ENABLE 0
3150	#define EV_FORK_ENABLE 0	3182	#define EV_FORK_ENABLE 0
3151	#define EV_CONFIG_H <config.h>	3183	#define EV_CONFIG_H <config.h>
3152	#define EV_MINPRI 0	3184	#define EV_MINPRI 0
3153	#define EV_MAXPRI 0	3185	#define EV_MAXPRI 0
3154		3186
3155	#include "ev++.h"	3187	#include "ev++.h"
3156		3188
3157	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	3189	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3158		3190
3159	#include "ev_cpp.h"	3191	#include "ev_cpp.h"
3160	#include "ev.c"	3192	#include "ev.c"
3161		3193
3162		3194
3163	=head1 THREADS AND COROUTINES	3195	=head1 THREADS AND COROUTINES
3164		3196
3165	=head2 THREADS	3197	=head2 THREADS
…		…
3173	parallel from multiple threads, calls with the same loop parameter must be	3205	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	3206	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	3207	thread ever is inside a call at any point in time, e.g. by using a mutex
3176	per loop).	3208	per loop).
3177		3209
3178	If you want to know which design is best for your problem, then I cannot	3210	If you want to know which design (one loop, locking, or multiple loops
3179	help you but by giving some generic advice:	3211	without or something else still) is best for your problem, then I cannot
		3212	help you. I can give some generic advice however:
3180		3213
3181	=over 4	3214	=over 4
3182		3215
3183	=item * most applications have a main thread: use the default libev loop	3216	=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.	3217	in that thread, or create a separate thread running only the default loop.
…		…
3285	involves iterating over all running async watchers or all signal numbers.	3318	involves iterating over all running async watchers or all signal numbers.
3286		3319
3287	=back	3320	=back
3288		3321
3289		3322
3290	=head1 Win32 platform limitations and workarounds	3323	=head1 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
3291		3324
3292	Win32 doesn't support any of the standards (e.g. POSIX) that libev	3325	Win32 doesn't support any of the standards (e.g. POSIX) that libev
3293	requires, and its I/O model is fundamentally incompatible with the POSIX	3326	requires, and its I/O model is fundamentally incompatible with the POSIX
3294	model. Libev still offers limited functionality on this platform in	3327	model. Libev still offers limited functionality on this platform in
3295	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	3328	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
…		…
3317	more than a hundred or so sockets, then likely it needs to use a totally	3350	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	3351	different implementation for windows, as libev offers the POSIX readiness
3319	notification model, which cannot be implemented efficiently on windows	3352	notification model, which cannot be implemented efficiently on windows
3320	(Microsoft monopoly games).	3353	(Microsoft monopoly games).
3321		3354
		3355	A typical way to use libev under windows is to embed it (see the embedding
		3356	section for details) and use the following F<evwrap.h> header file instead
		3357	of F<ev.h>:
		3358
		3359	#define EV_STANDALONE /* keeps ev from requiring config.h */
		3360	#define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
		3361
		3362	#include "ev.h"
		3363
		3364	And compile the following F<evwrap.c> file into your project (make sure
		3365	you do I<not> compile the F<ev.c> or any other embedded soruce files!):
		3366
		3367	#include "evwrap.h"
		3368	#include "ev.c"
		3369
3322	=over 4	3370	=over 4
3323		3371
3324	=item The winsocket select function	3372	=item The winsocket select function
3325		3373
3326	The winsocket C<select> function doesn't follow POSIX in that it	3374	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	3375	requires socket I<handles> and not socket I<file descriptors> (it is
3328	also extremely buggy). This makes select very inefficient, and also	3376	also extremely buggy). This makes select very inefficient, and also
3329	requires a mapping from file descriptors to socket handles. See the	3377	requires a mapping from file descriptors to socket handles (the Microsoft
		3378	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	3379	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.	3380	C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.
3332		3381
3333	The configuration for a "naked" win32 using the Microsoft runtime	3382	The configuration for a "naked" win32 using the Microsoft runtime
3334	libraries and raw winsocket select is:	3383	libraries and raw winsocket select is:
3335		3384
3336	#define EV_USE_SELECT 1	3385	#define EV_USE_SELECT 1
3337	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	3386	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
3338		3387
3339	Note that winsockets handling of fd sets is O(n), so you can easily get a	3388	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.	3389	complexity in the O(n²) range when using win32.
3341		3390
3342	=item Limited number of file descriptors	3391	=item Limited number of file descriptors
…		…
3374	In addition to a working ISO-C implementation, libev relies on a few	3423	In addition to a working ISO-C implementation, libev relies on a few
3375	additional extensions:	3424	additional extensions:
3376		3425
3377	=over 4	3426	=over 4
3378		3427
		3428	=item C<void ()(ev_watcher_type , int revents)> must have compatible
		3429	calling conventions regardless of C<ev_watcher_type *>.
		3430
		3431	Libev assumes not only that all watcher pointers have the same internal
		3432	structure (guaranteed by POSIX but not by ISO C for example), but it also
		3433	assumes that the same (machine) code can be used to call any watcher
		3434	callback: The watcher callbacks have different type signatures, but libev
		3435	calls them using an C<ev_watcher *> internally.
		3436
3379	=item C<sig_atomic_t volatile> must be thread-atomic as well	3437	=item C<sig_atomic_t volatile> must be thread-atomic as well
3380		3438
3381	The type C<sig_atomic_t volatile> (or whatever is defined as	3439	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	3440	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	3441	threads. This is not part of the specification for C<sig_atomic_t>, but is

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