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Revision 1.163 by root, Sat May 31 23:19:23 2008 UTC vs.
Revision 1.167 by root, Mon Jun 9 14:11:30 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
…		…
664	respectively).	664	respectively).
665		665
666	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	666	Example: Create a signal watcher, but keep it from keeping C<ev_loop>
667	running when nothing else is active.	667	running when nothing else is active.
668		668
669	struct ev_signal exitsig;	669	struct ev_signal exitsig;
670	ev_signal_init (&exitsig, sig_cb, SIGINT);	670	ev_signal_init (&exitsig, sig_cb, SIGINT);
671	ev_signal_start (loop, &exitsig);	671	ev_signal_start (loop, &exitsig);
672	evf_unref (loop);	672	evf_unref (loop);
673		673
674	Example: For some weird reason, unregister the above signal handler again.	674	Example: For some weird reason, unregister the above signal handler again.
675		675
676	ev_ref (loop);	676	ev_ref (loop);
677	ev_signal_stop (loop, &exitsig);	677	ev_signal_stop (loop, &exitsig);
678		678
679	=item ev_set_io_collect_interval (loop, ev_tstamp interval)	679	=item ev_set_io_collect_interval (loop, ev_tstamp interval)
680		680
681	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)	681	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
682		682
…		…
730		730
731	A watcher is a structure that you create and register to record your	731	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	732	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:	733	become readable, you would create an C<ev_io> watcher for that:
734		734
735	static void my_cb (struct ev_loop loop, struct ev_io w, int revents)	735	static void my_cb (struct ev_loop loop, struct ev_io w, int revents)
736	{	736	{
737	ev_io_stop (w);	737	ev_io_stop (w);
738	ev_unloop (loop, EVUNLOOP_ALL);	738	ev_unloop (loop, EVUNLOOP_ALL);
739	}	739	}
740		740
741	struct ev_loop *loop = ev_default_loop (0);	741	struct ev_loop *loop = ev_default_loop (0);
742	struct ev_io stdin_watcher;	742	struct ev_io stdin_watcher;
743	ev_init (&stdin_watcher, my_cb);	743	ev_init (&stdin_watcher, my_cb);
744	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	744	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
745	ev_io_start (loop, &stdin_watcher);	745	ev_io_start (loop, &stdin_watcher);
746	ev_loop (loop, 0);	746	ev_loop (loop, 0);
747		747
748	As you can see, you are responsible for allocating the memory for your	748	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,	749	watcher structures (and it is usually a bad idea to do this on the stack,
750	although this can sometimes be quite valid).	750	although this can sometimes be quite valid).
751		751
…		…
978	to associate arbitrary data with your watcher. If you need more data and	978	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	979	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	980	member, you can also "subclass" the watcher type and provide your own
981	data:	981	data:
982		982
983	struct my_io	983	struct my_io
984	{	984	{
985	struct ev_io io;	985	struct ev_io io;
986	int otherfd;	986	int otherfd;
987	void *somedata;	987	void *somedata;
988	struct whatever *mostinteresting;	988	struct whatever *mostinteresting;
989	}	989	}
990		990
991	And since your callback will be called with a pointer to the watcher, you	991	And since your callback will be called with a pointer to the watcher, you
992	can cast it back to your own type:	992	can cast it back to your own type:
993		993
994	static void my_cb (struct ev_loop loop, struct ev_io w_, int revents)	994	static void my_cb (struct ev_loop loop, struct ev_io w_, int revents)
995	{	995	{
996	struct my_io w = (struct my_io )w_;	996	struct my_io w = (struct my_io )w_;
997	...	997	...
998	}	998	}
999		999
1000	More interesting and less C-conformant ways of casting your callback type	1000	More interesting and less C-conformant ways of casting your callback type
1001	instead have been omitted.	1001	instead have been omitted.
1002		1002
1003	Another common scenario is having some data structure with multiple	1003	Another common scenario is having some data structure with multiple
1004	watchers:	1004	watchers:
1005		1005
1006	struct my_biggy	1006	struct my_biggy
1007	{	1007	{
1008	int some_data;	1008	int some_data;
1009	ev_timer t1;	1009	ev_timer t1;
1010	ev_timer t2;	1010	ev_timer t2;
1011	}	1011	}
1012		1012
1013	In this case getting the pointer to C<my_biggy> is a bit more complicated,	1013	In this case getting the pointer to C<my_biggy> is a bit more complicated,
1014	you need to use C<offsetof>:	1014	you need to use C<offsetof>:
1015		1015
1016	#include <stddef.h>	1016	#include <stddef.h>
1017		1017
1018	static void	1018	static void
1019	t1_cb (EV_P_ struct ev_timer *w, int revents)	1019	t1_cb (EV_P_ struct ev_timer *w, int revents)
1020	{	1020	{
1021	struct my_biggy big = (struct my_biggy *	1021	struct my_biggy big = (struct my_biggy *
1022	(((char *)w) - offsetof (struct my_biggy, t1));	1022	(((char *)w) - offsetof (struct my_biggy, t1));
1023	}	1023	}
1024		1024
1025	static void	1025	static void
1026	t2_cb (EV_P_ struct ev_timer *w, int revents)	1026	t2_cb (EV_P_ struct ev_timer *w, int revents)
1027	{	1027	{
1028	struct my_biggy big = (struct my_biggy *	1028	struct my_biggy big = (struct my_biggy *
1029	(((char *)w) - offsetof (struct my_biggy, t2));	1029	(((char *)w) - offsetof (struct my_biggy, t2));
1030	}	1030	}
1031		1031
1032		1032
1033	=head1 WATCHER TYPES	1033	=head1 WATCHER TYPES
1034		1034
1035	This section describes each watcher in detail, but will not repeat	1035	This section describes each watcher in detail, but will not repeat
…		…
1162		1162
1163	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well	1163	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	1164	readable, but only once. Since it is likely line-buffered, you could
1165	attempt to read a whole line in the callback.	1165	attempt to read a whole line in the callback.
1166		1166
1167	static void	1167	static void
1168	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	1168	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
1169	{	1169	{
1170	ev_io_stop (loop, w);	1170	ev_io_stop (loop, w);
1171	.. read from stdin here (or from w->fd) and haqndle any I/O errors	1171	.. read from stdin here (or from w->fd) and haqndle any I/O errors
1172	}	1172	}
1173		1173
1174	...	1174	...
1175	struct ev_loop *loop = ev_default_init (0);	1175	struct ev_loop *loop = ev_default_init (0);
1176	struct ev_io stdin_readable;	1176	struct ev_io stdin_readable;
1177	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1177	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1178	ev_io_start (loop, &stdin_readable);	1178	ev_io_start (loop, &stdin_readable);
1179	ev_loop (loop, 0);	1179	ev_loop (loop, 0);
1180		1180
1181		1181
1182	=head2 C<ev_timer> - relative and optionally repeating timeouts	1182	=head2 C<ev_timer> - relative and optionally repeating timeouts
1183		1183
1184	Timer watchers are simple relative timers that generate an event after a	1184	Timer watchers are simple relative timers that generate an event after a
…		…
1269		1269
1270	=head3 Examples	1270	=head3 Examples
1271		1271
1272	Example: Create a timer that fires after 60 seconds.	1272	Example: Create a timer that fires after 60 seconds.
1273		1273
1274	static void	1274	static void
1275	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1275	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
1276	{	1276	{
1277	.. one minute over, w is actually stopped right here	1277	.. one minute over, w is actually stopped right here
1278	}	1278	}
1279		1279
1280	struct ev_timer mytimer;	1280	struct ev_timer mytimer;
1281	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1281	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1282	ev_timer_start (loop, &mytimer);	1282	ev_timer_start (loop, &mytimer);
1283		1283
1284	Example: Create a timeout timer that times out after 10 seconds of	1284	Example: Create a timeout timer that times out after 10 seconds of
1285	inactivity.	1285	inactivity.
1286		1286
1287	static void	1287	static void
1288	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1288	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
1289	{	1289	{
1290	.. ten seconds without any activity	1290	.. ten seconds without any activity
1291	}	1291	}
1292		1292
1293	struct ev_timer mytimer;	1293	struct ev_timer mytimer;
1294	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	1294	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1295	ev_timer_again (&mytimer); /* start timer */	1295	ev_timer_again (&mytimer); /* start timer */
1296	ev_loop (loop, 0);	1296	ev_loop (loop, 0);
1297		1297
1298	// and in some piece of code that gets executed on any "activity":	1298	// and in some piece of code that gets executed on any "activity":
1299	// reset the timeout to start ticking again at 10 seconds	1299	// reset the timeout to start ticking again at 10 seconds
1300	ev_timer_again (&mytimer);	1300	ev_timer_again (&mytimer);
1301		1301
1302		1302
1303	=head2 C<ev_periodic> - to cron or not to cron?	1303	=head2 C<ev_periodic> - to cron or not to cron?
1304		1304
1305	Periodic watchers are also timers of a kind, but they are very versatile	1305	Periodic watchers are also timers of a kind, but they are very versatile
…		…
1448		1448
1449	Example: Call a callback every hour, or, more precisely, whenever the	1449	Example: Call a callback every hour, or, more precisely, whenever the
1450	system clock is divisible by 3600. The callback invocation times have	1450	system clock is divisible by 3600. The callback invocation times have
1451	potentially a lot of jitter, but good long-term stability.	1451	potentially a lot of jitter, but good long-term stability.
1452		1452
1453	static void	1453	static void
1454	clock_cb (struct ev_loop loop, struct ev_io w, int revents)	1454	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
1455	{	1455	{
1456	... its now a full hour (UTC, or TAI or whatever your clock follows)	1456	... its now a full hour (UTC, or TAI or whatever your clock follows)
1457	}	1457	}
1458		1458
1459	struct ev_periodic hourly_tick;	1459	struct ev_periodic hourly_tick;
1460	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1460	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1461	ev_periodic_start (loop, &hourly_tick);	1461	ev_periodic_start (loop, &hourly_tick);
1462		1462
1463	Example: The same as above, but use a reschedule callback to do it:	1463	Example: The same as above, but use a reschedule callback to do it:
1464		1464
1465	#include <math.h>	1465	#include <math.h>
1466		1466
1467	static ev_tstamp	1467	static ev_tstamp
1468	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1468	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1469	{	1469	{
1470	return fmod (now, 3600.) + 3600.;	1470	return fmod (now, 3600.) + 3600.;
1471	}	1471	}
1472		1472
1473	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1473	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1474		1474
1475	Example: Call a callback every hour, starting now:	1475	Example: Call a callback every hour, starting now:
1476		1476
1477	struct ev_periodic hourly_tick;	1477	struct ev_periodic hourly_tick;
1478	ev_periodic_init (&hourly_tick, clock_cb,	1478	ev_periodic_init (&hourly_tick, clock_cb,
1479	fmod (ev_now (loop), 3600.), 3600., 0);	1479	fmod (ev_now (loop), 3600.), 3600., 0);
1480	ev_periodic_start (loop, &hourly_tick);	1480	ev_periodic_start (loop, &hourly_tick);
1481		1481
1482		1482
1483	=head2 C<ev_signal> - signal me when a signal gets signalled!	1483	=head2 C<ev_signal> - signal me when a signal gets signalled!
1484		1484
1485	Signal watchers will trigger an event when the process receives a specific	1485	Signal watchers will trigger an event when the process receives a specific
…		…
1519		1519
1520	=head3 Examples	1520	=head3 Examples
1521		1521
1522	Example: Try to exit cleanly on SIGINT and SIGTERM.	1522	Example: Try to exit cleanly on SIGINT and SIGTERM.
1523		1523
1524	static void	1524	static void
1525	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1525	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1526	{	1526	{
1527	ev_unloop (loop, EVUNLOOP_ALL);	1527	ev_unloop (loop, EVUNLOOP_ALL);
1528	}	1528	}
1529		1529
1530	struct ev_signal signal_watcher;	1530	struct ev_signal signal_watcher;
1531	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1531	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1532	ev_signal_start (loop, &sigint_cb);	1532	ev_signal_start (loop, &sigint_cb);
1533		1533
1534		1534
1535	=head2 C<ev_child> - watch out for process status changes	1535	=head2 C<ev_child> - watch out for process status changes
1536		1536
1537	Child watchers trigger when your process receives a SIGCHLD in response to	1537	Child watchers trigger when your process receives a SIGCHLD in response to
…		…
1597	=head3 Examples	1597	=head3 Examples
1598		1598
1599	Example: C<fork()> a new process and install a child handler to wait for	1599	Example: C<fork()> a new process and install a child handler to wait for
1600	its completion.	1600	its completion.
1601		1601
1602	ev_child cw;	1602	ev_child cw;
1603		1603
1604	static void	1604	static void
1605	child_cb (EV_P_ struct ev_child *w, int revents)	1605	child_cb (EV_P_ struct ev_child *w, int revents)
1606	{	1606	{
1607	ev_child_stop (EV_A_ w);	1607	ev_child_stop (EV_A_ w);
1608	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);	1608	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
1609	}	1609	}
1610		1610
1611	pid_t pid = fork ();	1611	pid_t pid = fork ();
1612		1612
1613	if (pid < 0)	1613	if (pid < 0)
1614	// error	1614	// error
1615	else if (pid == 0)	1615	else if (pid == 0)
1616	{	1616	{
1617	// the forked child executes here	1617	// the forked child executes here
1618	exit (1);	1618	exit (1);
1619	}	1619	}
1620	else	1620	else
1621	{	1621	{
1622	ev_child_init (&cw, child_cb, pid, 0);	1622	ev_child_init (&cw, child_cb, pid, 0);
1623	ev_child_start (EV_DEFAULT_ &cw);	1623	ev_child_start (EV_DEFAULT_ &cw);
1624	}	1624	}
1625		1625
1626		1626
1627	=head2 C<ev_stat> - did the file attributes just change?	1627	=head2 C<ev_stat> - did the file attributes just change?
1628		1628
1629	This watches a file system path for attribute changes. That is, it calls	1629	This watches a file system path for attribute changes. That is, it calls
…		…
1767		1767
1768	=head3 Examples	1768	=head3 Examples
1769		1769
1770	Example: Watch C</etc/passwd> for attribute changes.	1770	Example: Watch C</etc/passwd> for attribute changes.
1771		1771
1772	static void	1772	static void
1773	passwd_cb (struct ev_loop loop, ev_stat w, int revents)	1773	passwd_cb (struct ev_loop loop, ev_stat w, int revents)
1774	{	1774	{
1775	/* /etc/passwd changed in some way */	1775	/* /etc/passwd changed in some way */
1776	if (w->attr.st_nlink)	1776	if (w->attr.st_nlink)
1777	{	1777	{
1778	printf ("passwd current size %ld\n", (long)w->attr.st_size);	1778	printf ("passwd current size %ld\n", (long)w->attr.st_size);
1779	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);	1779	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
1780	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);	1780	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
1781	}	1781	}
1782	else	1782	else
1783	/* you shalt not abuse printf for puts */	1783	/* you shalt not abuse printf for puts */
1784	puts ("wow, /etc/passwd is not there, expect problems. "	1784	puts ("wow, /etc/passwd is not there, expect problems. "
1785	"if this is windows, they already arrived\n");	1785	"if this is windows, they already arrived\n");
1786	}	1786	}
1787		1787
1788	...	1788	...
1789	ev_stat passwd;	1789	ev_stat passwd;
1790		1790
1791	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);	1791	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
1792	ev_stat_start (loop, &passwd);	1792	ev_stat_start (loop, &passwd);
1793		1793
1794	Example: Like above, but additionally use a one-second delay so we do not	1794	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	1795	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	1796	one might do the work both on C<ev_stat> callback invocation I<and> on
1797	C<ev_timer> callback invocation).	1797	C<ev_timer> callback invocation).
1798		1798
1799	static ev_stat passwd;	1799	static ev_stat passwd;
1800	static ev_timer timer;	1800	static ev_timer timer;
1801		1801
1802	static void	1802	static void
1803	timer_cb (EV_P_ ev_timer *w, int revents)	1803	timer_cb (EV_P_ ev_timer *w, int revents)
1804	{	1804	{
1805	ev_timer_stop (EV_A_ w);	1805	ev_timer_stop (EV_A_ w);
1806		1806
1807	/* now it's one second after the most recent passwd change */	1807	/* now it's one second after the most recent passwd change */
1808	}	1808	}
1809		1809
1810	static void	1810	static void
1811	stat_cb (EV_P_ ev_stat *w, int revents)	1811	stat_cb (EV_P_ ev_stat *w, int revents)
1812	{	1812	{
1813	/* reset the one-second timer */	1813	/* reset the one-second timer */
1814	ev_timer_again (EV_A_ &timer);	1814	ev_timer_again (EV_A_ &timer);
1815	}	1815	}
1816		1816
1817	...	1817	...
1818	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);	1818	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
1819	ev_stat_start (loop, &passwd);	1819	ev_stat_start (loop, &passwd);
1820	ev_timer_init (&timer, timer_cb, 0., 1.02);	1820	ev_timer_init (&timer, timer_cb, 0., 1.02);
1821		1821
1822		1822
1823	=head2 C<ev_idle> - when you've got nothing better to do...	1823	=head2 C<ev_idle> - when you've got nothing better to do...
1824		1824
1825	Idle watchers trigger events when no other events of the same or higher	1825	Idle watchers trigger events when no other events of the same or higher
…		…
1856	=head3 Examples	1856	=head3 Examples
1857		1857
1858	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the	1858	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1859	callback, free it. Also, use no error checking, as usual.	1859	callback, free it. Also, use no error checking, as usual.
1860		1860
1861	static void	1861	static void
1862	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1862	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1863	{	1863	{
1864	free (w);	1864	free (w);
1865	// now do something you wanted to do when the program has	1865	// now do something you wanted to do when the program has
1866	// no longer anything immediate to do.	1866	// no longer anything immediate to do.
1867	}	1867	}
1868		1868
1869	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1869	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1870	ev_idle_init (idle_watcher, idle_cb);	1870	ev_idle_init (idle_watcher, idle_cb);
1871	ev_idle_start (loop, idle_cb);	1871	ev_idle_start (loop, idle_cb);
1872		1872
1873		1873
1874	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!	1874	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
1875		1875
1876	Prepare and check watchers are usually (but not always) used in tandem:	1876	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	1948	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	1949	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	1950	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.	1951	the callbacks for the IO/timeout watchers might not have been called yet.
1952		1952
1953	static ev_io iow [nfd];	1953	static ev_io iow [nfd];
1954	static ev_timer tw;	1954	static ev_timer tw;
1955		1955
1956	static void	1956	static void
1957	io_cb (ev_loop loop, ev_io w, int revents)	1957	io_cb (ev_loop loop, ev_io w, int revents)
1958	{	1958	{
1959	}	1959	}
1960		1960
1961	// create io watchers for each fd and a timer before blocking	1961	// create io watchers for each fd and a timer before blocking
1962	static void	1962	static void
1963	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1963	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1964	{	1964	{
1965	int timeout = 3600000;	1965	int timeout = 3600000;
1966	struct pollfd fds [nfd];	1966	struct pollfd fds [nfd];
1967	// actual code will need to loop here and realloc etc.	1967	// actual code will need to loop here and realloc etc.
1968	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1968	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1969		1969
1970	/* the callback is illegal, but won't be called as we stop during check */	1970	/* the callback is illegal, but won't be called as we stop during check */
1971	ev_timer_init (&tw, 0, timeout * 1e-3);	1971	ev_timer_init (&tw, 0, timeout * 1e-3);
1972	ev_timer_start (loop, &tw);	1972	ev_timer_start (loop, &tw);
1973		1973
1974	// create one ev_io per pollfd	1974	// create one ev_io per pollfd
1975	for (int i = 0; i < nfd; ++i)	1975	for (int i = 0; i < nfd; ++i)
1976	{	1976	{
1977	ev_io_init (iow + i, io_cb, fds [i].fd,	1977	ev_io_init (iow + i, io_cb, fds [i].fd,
1978	((fds [i].events & POLLIN ? EV_READ : 0)	1978	((fds [i].events & POLLIN ? EV_READ : 0)
1979	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	1979	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1980		1980
1981	fds [i].revents = 0;	1981	fds [i].revents = 0;
1982	ev_io_start (loop, iow + i);	1982	ev_io_start (loop, iow + i);
1983	}	1983	}
1984	}	1984	}
1985		1985
1986	// stop all watchers after blocking	1986	// stop all watchers after blocking
1987	static void	1987	static void
1988	adns_check_cb (ev_loop loop, ev_check w, int revents)	1988	adns_check_cb (ev_loop loop, ev_check w, int revents)
1989	{	1989	{
1990	ev_timer_stop (loop, &tw);	1990	ev_timer_stop (loop, &tw);
1991		1991
1992	for (int i = 0; i < nfd; ++i)	1992	for (int i = 0; i < nfd; ++i)
1993	{	1993	{
1994	// set the relevant poll flags	1994	// set the relevant poll flags
1995	// could also call adns_processreadable etc. here	1995	// could also call adns_processreadable etc. here
1996	struct pollfd *fd = fds + i;	1996	struct pollfd *fd = fds + i;
1997	int revents = ev_clear_pending (iow + i);	1997	int revents = ev_clear_pending (iow + i);
1998	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;	1998	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
1999	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;	1999	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
2000		2000
2001	// now stop the watcher	2001	// now stop the watcher
2002	ev_io_stop (loop, iow + i);	2002	ev_io_stop (loop, iow + i);
2003	}	2003	}
2004		2004
2005	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	2005	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
2006	}	2006	}
2007		2007
2008	Method 2: This would be just like method 1, but you run C<adns_afterpoll>	2008	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.	2009	in the prepare watcher and would dispose of the check watcher.
2010		2010
2011	Method 3: If the module to be embedded supports explicit event	2011	Method 3: If the module to be embedded supports explicit event
2012	notification (libadns does), you can also make use of the actual watcher	2012	notification (libadns does), you can also make use of the actual watcher
2013	callbacks, and only destroy/create the watchers in the prepare watcher.	2013	callbacks, and only destroy/create the watchers in the prepare watcher.
2014		2014
2015	static void	2015	static void
2016	timer_cb (EV_P_ ev_timer *w, int revents)	2016	timer_cb (EV_P_ ev_timer *w, int revents)
2017	{	2017	{
2018	adns_state ads = (adns_state)w->data;	2018	adns_state ads = (adns_state)w->data;
2019	update_now (EV_A);	2019	update_now (EV_A);
2020		2020
2021	adns_processtimeouts (ads, &tv_now);	2021	adns_processtimeouts (ads, &tv_now);
2022	}	2022	}
2023		2023
2024	static void	2024	static void
2025	io_cb (EV_P_ ev_io *w, int revents)	2025	io_cb (EV_P_ ev_io *w, int revents)
2026	{	2026	{
2027	adns_state ads = (adns_state)w->data;	2027	adns_state ads = (adns_state)w->data;
2028	update_now (EV_A);	2028	update_now (EV_A);
2029		2029
2030	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);	2030	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
2031	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);	2031	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
2032	}	2032	}
2033		2033
2034	// do not ever call adns_afterpoll	2034	// do not ever call adns_afterpoll
2035		2035
2036	Method 4: Do not use a prepare or check watcher because the module you	2036	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	2037	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	2038	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	2039	loop is now no longer controllable by EV. The C<Glib::EV> module does
2040	this.	2040	this.
2041		2041
2042	static gint	2042	static gint
2043	event_poll_func (GPollFD *fds, guint nfds, gint timeout)	2043	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
2044	{	2044	{
2045	int got_events = 0;	2045	int got_events = 0;
2046		2046
2047	for (n = 0; n < nfds; ++n)	2047	for (n = 0; n < nfds; ++n)
2048	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events	2048	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
2049		2049
2050	if (timeout >= 0)	2050	if (timeout >= 0)
2051	// create/start timer	2051	// create/start timer
2052		2052
2053	// poll	2053	// poll
2054	ev_loop (EV_A_ 0);	2054	ev_loop (EV_A_ 0);
2055		2055
2056	// stop timer again	2056	// stop timer again
2057	if (timeout >= 0)	2057	if (timeout >= 0)
2058	ev_timer_stop (EV_A_ &to);	2058	ev_timer_stop (EV_A_ &to);
2059		2059
2060	// stop io watchers again - their callbacks should have set	2060	// stop io watchers again - their callbacks should have set
2061	for (n = 0; n < nfds; ++n)	2061	for (n = 0; n < nfds; ++n)
2062	ev_io_stop (EV_A_ iow [n]);	2062	ev_io_stop (EV_A_ iow [n]);
2063		2063
2064	return got_events;	2064	return got_events;
2065	}	2065	}
2066		2066
2067		2067
2068	=head2 C<ev_embed> - when one backend isn't enough...	2068	=head2 C<ev_embed> - when one backend isn't enough...
2069		2069
2070	This is a rather advanced watcher type that lets you embed one event loop	2070	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	2148	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	2149	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	2150	C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
2151	used).	2151	used).
2152		2152
2153	struct ev_loop *loop_hi = ev_default_init (0);	2153	struct ev_loop *loop_hi = ev_default_init (0);
2154	struct ev_loop *loop_lo = 0;	2154	struct ev_loop *loop_lo = 0;
2155	struct ev_embed embed;	2155	struct ev_embed embed;
2156		2156
2157	// see if there is a chance of getting one that works	2157	// see if there is a chance of getting one that works
2158	// (remember that a flags value of 0 means autodetection)	2158	// (remember that a flags value of 0 means autodetection)
2159	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()	2159	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
2160	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())	2160	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
2161	: 0;	2161	: 0;
2162		2162
2163	// if we got one, then embed it, otherwise default to loop_hi	2163	// if we got one, then embed it, otherwise default to loop_hi
2164	if (loop_lo)	2164	if (loop_lo)
2165	{	2165	{
2166	ev_embed_init (&embed, 0, loop_lo);	2166	ev_embed_init (&embed, 0, loop_lo);
2167	ev_embed_start (loop_hi, &embed);	2167	ev_embed_start (loop_hi, &embed);
2168	}	2168	}
2169	else	2169	else
2170	loop_lo = loop_hi;	2170	loop_lo = loop_hi;
2171		2171
2172	Example: Check if kqueue is available but not recommended and create	2172	Example: Check if kqueue is available but not recommended and create
2173	a kqueue backend for use with sockets (which usually work with any	2173	a kqueue backend for use with sockets (which usually work with any
2174	kqueue implementation). Store the kqueue/socket-only event loop in	2174	kqueue implementation). Store the kqueue/socket-only event loop in
2175	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).	2175	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
2176		2176
2177	struct ev_loop *loop = ev_default_init (0);	2177	struct ev_loop *loop = ev_default_init (0);
2178	struct ev_loop *loop_socket = 0;	2178	struct ev_loop *loop_socket = 0;
2179	struct ev_embed embed;	2179	struct ev_embed embed;
2180		2180
2181	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)	2181	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
2182	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))	2182	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
2183	{	2183	{
2184	ev_embed_init (&embed, 0, loop_socket);	2184	ev_embed_init (&embed, 0, loop_socket);
2185	ev_embed_start (loop, &embed);	2185	ev_embed_start (loop, &embed);
2186	}	2186	}
2187		2187
2188	if (!loop_socket)	2188	if (!loop_socket)
2189	loop_socket = loop;	2189	loop_socket = loop;
2190		2190
2191	// now use loop_socket for all sockets, and loop for everything else	2191	// now use loop_socket for all sockets, and loop for everything else
2192		2192
2193		2193
2194	=head2 C<ev_fork> - the audacity to resume the event loop after a fork	2194	=head2 C<ev_fork> - the audacity to resume the event loop after a fork
2195		2195
2196	Fork watchers are called when a C<fork ()> was detected (usually because	2196	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	2385	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	2386	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>	2387	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
2388	value passed to C<ev_once>:	2388	value passed to C<ev_once>:
2389		2389
2390	static void stdin_ready (int revents, void *arg)	2390	static void stdin_ready (int revents, void *arg)
2391	{	2391	{
2392	if (revents & EV_TIMEOUT)	2392	if (revents & EV_TIMEOUT)
2393	/* doh, nothing entered */;	2393	/* doh, nothing entered */;
2394	else if (revents & EV_READ)	2394	else if (revents & EV_READ)
2395	/* stdin might have data for us, joy! */;	2395	/* stdin might have data for us, joy! */;
2396	}	2396	}
2397		2397
2398	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2398	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2399		2399
2400	=item ev_feed_event (ev_loop , watcher , int revents)	2400	=item ev_feed_event (ev_loop , watcher , int revents)
2401		2401
2402	Feeds the given event set into the event loop, as if the specified event	2402	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	2403	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	2452	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.	2453	the callback model to a model using method callbacks on objects.
2454		2454
2455	To use it,	2455	To use it,
2456		2456
2457	#include <ev++.h>	2457	#include <ev++.h>
2458		2458
2459	This automatically includes F<ev.h> and puts all of its definitions (many	2459	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	2460	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	2461	put into the C<ev> namespace. It should support all the same embedding
2462	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.	2462	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
…		…
2529	your compiler is good :), then the method will be fully inlined into the	2529	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.	2530	thunking function, making it as fast as a direct C callback.
2531		2531
2532	Example: simple class declaration and watcher initialisation	2532	Example: simple class declaration and watcher initialisation
2533		2533
2534	struct myclass	2534	struct myclass
2535	{	2535	{
2536	void io_cb (ev::io &w, int revents) { }	2536	void io_cb (ev::io &w, int revents) { }
2537	}	2537	}
2538		2538
2539	myclass obj;	2539	myclass obj;
2540	ev::io iow;	2540	ev::io iow;
2541	iow.set <myclass, &myclass::io_cb> (&obj);	2541	iow.set <myclass, &myclass::io_cb> (&obj);
2542		2542
2543	=item w->set<function> (void *data = 0)	2543	=item w->set<function> (void *data = 0)
2544		2544
2545	Also sets a callback, but uses a static method or plain function as	2545	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	2546	callback. The optional C<data> argument will be stored in the watcher's
…		…
2550		2550
2551	See the method-C<set> above for more details.	2551	See the method-C<set> above for more details.
2552		2552
2553	Example:	2553	Example:
2554		2554
2555	static void io_cb (ev::io &w, int revents) { }	2555	static void io_cb (ev::io &w, int revents) { }
2556	iow.set <io_cb> ();	2556	iow.set <io_cb> ();
2557		2557
2558	=item w->set (struct ev_loop *)	2558	=item w->set (struct ev_loop *)
2559		2559
2560	Associates a different C<struct ev_loop> with this watcher. You can only	2560	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).	2561	do this when the watcher is inactive (and not pending either).
…		…
2594	=back	2594	=back
2595		2595
2596	Example: Define a class with an IO and idle watcher, start one of them in	2596	Example: Define a class with an IO and idle watcher, start one of them in
2597	the constructor.	2597	the constructor.
2598		2598
2599	class myclass	2599	class myclass
2600	{	2600	{
2601	ev::io io; void io_cb (ev::io &w, int revents);	2601	ev::io io; void io_cb (ev::io &w, int revents);
2602	ev:idle idle void idle_cb (ev::idle &w, int revents);	2602	ev:idle idle void idle_cb (ev::idle &w, int revents);
2603		2603
2604	myclass (int fd)	2604	myclass (int fd)
2605	{	2605	{
2606	io .set <myclass, &myclass::io_cb > (this);	2606	io .set <myclass, &myclass::io_cb > (this);
2607	idle.set <myclass, &myclass::idle_cb> (this);	2607	idle.set <myclass, &myclass::idle_cb> (this);
2608		2608
2609	io.start (fd, ev::READ);	2609	io.start (fd, ev::READ);
2610	}	2610	}
2611	};	2611	};
2612		2612
2613		2613
2614	=head1 OTHER LANGUAGE BINDINGS	2614	=head1 OTHER LANGUAGE BINDINGS
2615		2615
2616	Libev does not offer other language bindings itself, but bindings for a	2616	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,	2626	libev. EV is developed together with libev. Apart from the EV core module,
2627	there are additional modules that implement libev-compatible interfaces	2627	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	2628	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>).	2629	C<libglib> event core (C<Glib::EV> and C<EV::Glib>).
2630		2630
2631	It can be found and installed via CPAN, its homepage is found at	2631	It can be found and installed via CPAN, its homepage is at
2632	L<http://software.schmorp.de/pkg/EV>.	2632	L<http://software.schmorp.de/pkg/EV>.
		2633
		2634	=item Python
		2635
		2636	Python bindings can be found at L<http://code.google.com/p/pyev/>. It
		2637	seems to be quite complete and well-documented. Note, however, that the
		2638	patch they require for libev is outright dangerous as it breaks the ABI
		2639	for everybody else, and therefore, should never be applied in an installed
		2640	libev (if python requires an incompatible ABI then it needs to embed
		2641	libev).
2633		2642
2634	=item Ruby	2643	=item Ruby
2635		2644
2636	Tony Arcieri has written a ruby extension that offers access to a subset	2645	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	2646	of the libev API and adds file handle abstractions, asynchronous DNS and
…		…
2661		2670
2662	This provides the loop I<argument> for functions, if one is required ("ev	2671	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,	2672	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:	2673	C<EV_A_> is used when other arguments are following. Example:
2665		2674
2666	ev_unref (EV_A);	2675	ev_unref (EV_A);
2667	ev_timer_add (EV_A_ watcher);	2676	ev_timer_add (EV_A_ watcher);
2668	ev_loop (EV_A_ 0);	2677	ev_loop (EV_A_ 0);
2669		2678
2670	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	2679	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
2671	which is often provided by the following macro.	2680	which is often provided by the following macro.
2672		2681
2673	=item C<EV_P>, C<EV_P_>	2682	=item C<EV_P>, C<EV_P_>
2674		2683
2675	This provides the loop I<parameter> for functions, if one is required ("ev	2684	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,	2685	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:	2686	C<EV_P_> is used when other parameters are following. Example:
2678		2687
2679	// this is how ev_unref is being declared	2688	// this is how ev_unref is being declared
2680	static void ev_unref (EV_P);	2689	static void ev_unref (EV_P);
2681		2690
2682	// this is how you can declare your typical callback	2691	// this is how you can declare your typical callback
2683	static void cb (EV_P_ ev_timer *w, int revents)	2692	static void cb (EV_P_ ev_timer *w, int revents)
2684		2693
2685	It declares a parameter C<loop> of type C<struct ev_loop *>, quite	2694	It declares a parameter C<loop> of type C<struct ev_loop *>, quite
2686	suitable for use with C<EV_A>.	2695	suitable for use with C<EV_A>.
2687		2696
2688	=item C<EV_DEFAULT>, C<EV_DEFAULT_>	2697	=item C<EV_DEFAULT>, C<EV_DEFAULT_>
…		…
2704		2713
2705	Example: Declare and initialise a check watcher, utilising the above	2714	Example: Declare and initialise a check watcher, utilising the above
2706	macros so it will work regardless of whether multiple loops are supported	2715	macros so it will work regardless of whether multiple loops are supported
2707	or not.	2716	or not.
2708		2717
2709	static void	2718	static void
2710	check_cb (EV_P_ ev_timer *w, int revents)	2719	check_cb (EV_P_ ev_timer *w, int revents)
2711	{	2720	{
2712	ev_check_stop (EV_A_ w);	2721	ev_check_stop (EV_A_ w);
2713	}	2722	}
2714		2723
2715	ev_check check;	2724	ev_check check;
2716	ev_check_init (&check, check_cb);	2725	ev_check_init (&check, check_cb);
2717	ev_check_start (EV_DEFAULT_ &check);	2726	ev_check_start (EV_DEFAULT_ &check);
2718	ev_loop (EV_DEFAULT_ 0);	2727	ev_loop (EV_DEFAULT_ 0);
2719		2728
2720	=head1 EMBEDDING	2729	=head1 EMBEDDING
2721		2730
2722	Libev can (and often is) directly embedded into host	2731	Libev can (and often is) directly embedded into host
2723	applications. Examples of applications that embed it include the Deliantra	2732	applications. Examples of applications that embed it include the Deliantra
…		…
2737	=head3 CORE EVENT LOOP	2746	=head3 CORE EVENT LOOP
2738		2747
2739	To include only the libev core (all the C<ev_*> functions), with manual	2748	To include only the libev core (all the C<ev_*> functions), with manual
2740	configuration (no autoconf):	2749	configuration (no autoconf):
2741		2750
2742	#define EV_STANDALONE 1	2751	#define EV_STANDALONE 1
2743	#include "ev.c"	2752	#include "ev.c"
2744		2753
2745	This will automatically include F<ev.h>, too, and should be done in a	2754	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	2755	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	2756	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	2757	done by writing a wrapper around F<ev.h> that you can include instead and
2749	where you can put other configuration options):	2758	where you can put other configuration options):
2750		2759
2751	#define EV_STANDALONE 1	2760	#define EV_STANDALONE 1
2752	#include "ev.h"	2761	#include "ev.h"
2753		2762
2754	Both header files and implementation files can be compiled with a C++	2763	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	2764	compiler (at least, thats a stated goal, and breakage will be treated
2756	as a bug).	2765	as a bug).
2757		2766
2758	You need the following files in your source tree, or in a directory	2767	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):	2768	in your include path (e.g. in libev/ when using -Ilibev):
2760		2769
2761	ev.h	2770	ev.h
2762	ev.c	2771	ev.c
2763	ev_vars.h	2772	ev_vars.h
2764	ev_wrap.h	2773	ev_wrap.h
2765		2774
2766	ev_win32.c required on win32 platforms only	2775	ev_win32.c required on win32 platforms only
2767		2776
2768	ev_select.c only when select backend is enabled (which is enabled by default)	2777	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)	2778	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)	2779	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)	2780	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)	2781	ev_port.c only when the solaris port backend is enabled (disabled by default)
2773		2782
2774	F<ev.c> includes the backend files directly when enabled, so you only need	2783	F<ev.c> includes the backend files directly when enabled, so you only need
2775	to compile this single file.	2784	to compile this single file.
2776		2785
2777	=head3 LIBEVENT COMPATIBILITY API	2786	=head3 LIBEVENT COMPATIBILITY API
2778		2787
2779	To include the libevent compatibility API, also include:	2788	To include the libevent compatibility API, also include:
2780		2789
2781	#include "event.c"	2790	#include "event.c"
2782		2791
2783	in the file including F<ev.c>, and:	2792	in the file including F<ev.c>, and:
2784		2793
2785	#include "event.h"	2794	#include "event.h"
2786		2795
2787	in the files that want to use the libevent API. This also includes F<ev.h>.	2796	in the files that want to use the libevent API. This also includes F<ev.h>.
2788		2797
2789	You need the following additional files for this:	2798	You need the following additional files for this:
2790		2799
2791	event.h	2800	event.h
2792	event.c	2801	event.c
2793		2802
2794	=head3 AUTOCONF SUPPORT	2803	=head3 AUTOCONF SUPPORT
2795		2804
2796	Instead of using C<EV_STANDALONE=1> and providing your configuration in	2805	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	2806	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	2807	F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then
2799	include F<config.h> and configure itself accordingly.	2808	include F<config.h> and configure itself accordingly.
2800		2809
2801	For this of course you need the m4 file:	2810	For this of course you need the m4 file:
2802		2811
2803	libev.m4	2812	libev.m4
2804		2813
2805	=head2 PREPROCESSOR SYMBOLS/MACROS	2814	=head2 PREPROCESSOR SYMBOLS/MACROS
2806		2815
2807	Libev can be configured via a variety of preprocessor symbols you have to	2816	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	2817	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,	3094	members. You have to define it each time you include one of the files,
3086	though, and it must be identical each time.	3095	though, and it must be identical each time.
3087		3096
3088	For example, the perl EV module uses something like this:	3097	For example, the perl EV module uses something like this:
3089		3098
3090	#define EV_COMMON \	3099	#define EV_COMMON \
3091	SV self; / contains this struct */ \	3100	SV self; / contains this struct */ \
3092	SV cb_sv, fh /* note no trailing ";" */	3101	SV cb_sv, fh /* note no trailing ";" */
3093		3102
3094	=item EV_CB_DECLARE (type)	3103	=item EV_CB_DECLARE (type)
3095		3104
3096	=item EV_CB_INVOKE (watcher, revents)	3105	=item EV_CB_INVOKE (watcher, revents)
3097		3106
…		…
3108		3117
3109	If you need to re-export the API (e.g. via a DLL) and you need a list of	3118	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	3119	exported symbols, you can use the provided F<Symbol.*> files which list
3111	all public symbols, one per line:	3120	all public symbols, one per line:
3112		3121
3113	Symbols.ev for libev proper	3122	Symbols.ev for libev proper
3114	Symbols.event for the libevent emulation	3123	Symbols.event for the libevent emulation
3115		3124
3116	This can also be used to rename all public symbols to avoid clashes with	3125	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	3126	multiple versions of libev linked together (which is obviously bad in
3118	itself, but sometimes it is inconvenient to avoid this).	3127	itself, but sometimes it is inconvenient to avoid this).
3119		3128
…		…
3140	file.	3149	file.
3141		3150
3142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	3151	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:	3152	that everybody includes and which overrides some configure choices:
3144		3153
3145	#define EV_MINIMAL 1	3154	#define EV_MINIMAL 1
3146	#define EV_USE_POLL 0	3155	#define EV_USE_POLL 0
3147	#define EV_MULTIPLICITY 0	3156	#define EV_MULTIPLICITY 0
3148	#define EV_PERIODIC_ENABLE 0	3157	#define EV_PERIODIC_ENABLE 0
3149	#define EV_STAT_ENABLE 0	3158	#define EV_STAT_ENABLE 0
3150	#define EV_FORK_ENABLE 0	3159	#define EV_FORK_ENABLE 0
3151	#define EV_CONFIG_H <config.h>	3160	#define EV_CONFIG_H <config.h>
3152	#define EV_MINPRI 0	3161	#define EV_MINPRI 0
3153	#define EV_MAXPRI 0	3162	#define EV_MAXPRI 0
3154		3163
3155	#include "ev++.h"	3164	#include "ev++.h"
3156		3165
3157	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	3166	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3158		3167
3159	#include "ev_cpp.h"	3168	#include "ev_cpp.h"
3160	#include "ev.c"	3169	#include "ev.c"
3161		3170
3162		3171
3163	=head1 THREADS AND COROUTINES	3172	=head1 THREADS AND COROUTINES
3164		3173
3165	=head2 THREADS	3174	=head2 THREADS
…		…
3317	more than a hundred or so sockets, then likely it needs to use a totally	3326	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	3327	different implementation for windows, as libev offers the POSIX readiness
3319	notification model, which cannot be implemented efficiently on windows	3328	notification model, which cannot be implemented efficiently on windows
3320	(Microsoft monopoly games).	3329	(Microsoft monopoly games).
3321		3330
		3331	A typical way to use libev under windows is to embed it (see the embedding
		3332	section for details) and use the following F<evwrap.h> header file instead
		3333	of F<ev.h>:
		3334
		3335	#define EV_STANDALONE /* keeps ev from requiring config.h */
		3336	#define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
		3337	#define EV_STAT_ENABLE 0 /* no stat() availble */
		3338
		3339	#include "ev.h"
		3340
		3341	And compile the following F<evwrap.c> file into your project (make sure
		3342	you do I<not> compile the F<ev.c> or any other embedded soruce files!):
		3343
		3344	#include "evwrap.h"
		3345	#include "ev.c"
		3346
3322	=over 4	3347	=over 4
3323		3348
3324	=item The winsocket select function	3349	=item The winsocket select function
3325		3350
3326	The winsocket C<select> function doesn't follow POSIX in that it	3351	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	3352	requires socket I<handles> and not socket I<file descriptors> (it is
3328	also extremely buggy). This makes select very inefficient, and also	3353	also extremely buggy). This makes select very inefficient, and also
3329	requires a mapping from file descriptors to socket handles. See the	3354	requires a mapping from file descriptors to socket handles (the Microsoft
		3355	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	3356	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.	3357	C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.
3332		3358
3333	The configuration for a "naked" win32 using the Microsoft runtime	3359	The configuration for a "naked" win32 using the Microsoft runtime
3334	libraries and raw winsocket select is:	3360	libraries and raw winsocket select is:
3335		3361
3336	#define EV_USE_SELECT 1	3362	#define EV_USE_SELECT 1
3337	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	3363	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
3338		3364
3339	Note that winsockets handling of fd sets is O(n), so you can easily get a	3365	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.	3366	complexity in the O(n²) range when using win32.
3341		3367
3342	=item Limited number of file descriptors	3368	=item Limited number of file descriptors
…		…
3374	In addition to a working ISO-C implementation, libev relies on a few	3400	In addition to a working ISO-C implementation, libev relies on a few
3375	additional extensions:	3401	additional extensions:
3376		3402
3377	=over 4	3403	=over 4
3378		3404
		3405	=item C<void ()(ev_watcher_type , int revents)> must have compatible
		3406	calling conventions regardless of C<ev_watcher_type *>.
		3407
		3408	Libev assumes not only that all watcher pointers have the same internal
		3409	structure (guaranteed by POSIX but not by ISO C for example), but it also
		3410	assumes that the same (machine) code can be used to call any watcher
		3411	callback: The watcher callbacks have different type signatures, but libev
		3412	calls them using an C<ev_watcher *> internally.
		3413
3379	=item C<sig_atomic_t volatile> must be thread-atomic as well	3414	=item C<sig_atomic_t volatile> must be thread-atomic as well
3380		3415
3381	The type C<sig_atomic_t volatile> (or whatever is defined as	3416	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	3417	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	3418	threads. This is not part of the specification for C<sig_atomic_t>, but is

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