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

Comparing libev/ev.pod (file contents):
Revision 1.52 by root, Tue Nov 27 19:41:52 2007 UTC vs.
Revision 1.74 by root, Sat Dec 8 14:12:08 2007 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	#include <ev.h>	7	#include <ev.h>
8		8
		9	=head1 EXAMPLE PROGRAM
		10
		11	#include <ev.h>
		12
		13	ev_io stdin_watcher;
		14	ev_timer timeout_watcher;
		15
		16	/* called when data readable on stdin */
		17	static void
		18	stdin_cb (EV_P_ struct ev_io *w, int revents)
		19	{
		20	/* puts ("stdin ready"); */
		21	ev_io_stop (EV_A_ w); /* just a syntax example */
		22	ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */
		23	}
		24
		25	static void
		26	timeout_cb (EV_P_ struct ev_timer *w, int revents)
		27	{
		28	/* puts ("timeout"); */
		29	ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */
		30	}
		31
		32	int
		33	main (void)
		34	{
		35	struct ev_loop *loop = ev_default_loop (0);
		36
		37	/* initialise an io watcher, then start it */
		38	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
		39	ev_io_start (loop, &stdin_watcher);
		40
		41	/* simple non-repeating 5.5 second timeout */
		42	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
		43	ev_timer_start (loop, &timeout_watcher);
		44
		45	/* loop till timeout or data ready */
		46	ev_loop (loop, 0);
		47
		48	return 0;
		49	}
		50
9	=head1 DESCRIPTION	51	=head1 DESCRIPTION
		52
		53	The newest version of this document is also available as a html-formatted
		54	web page you might find easier to navigate when reading it for the first
		55	time: L<http://cvs.schmorp.de/libev/ev.html>.
10		56
11	Libev is an event loop: you register interest in certain events (such as a	57	Libev is an event loop: you register interest in certain events (such as a
12	file descriptor being readable or a timeout occuring), and it will manage	58	file descriptor being readable or a timeout occuring), and it will manage
13	these event sources and provide your program with events.	59	these event sources and provide your program with events.
14		60
…		…
21	details of the event, and then hand it over to libev by I<starting> the	67	details of the event, and then hand it over to libev by I<starting> the
22	watcher.	68	watcher.
23		69
24	=head1 FEATURES	70	=head1 FEATURES
25		71
26	Libev supports select, poll, the linux-specific epoll and the bsd-specific	72	Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the
27	kqueue mechanisms for file descriptor events, relative timers, absolute	73	BSD-specific C<kqueue> and the Solaris-specific event port mechanisms
28	timers with customised rescheduling, signal events, process status change	74	for file descriptor events (C<ev_io>), the Linux C<inotify> interface
29	events (related to SIGCHLD), and event watchers dealing with the event	75	(for C<ev_stat>), relative timers (C<ev_timer>), absolute timers
30	loop mechanism itself (idle, prepare and check watchers). It also is quite	76	with customised rescheduling (C<ev_periodic>), synchronous signals
		77	(C<ev_signal>), process status change events (C<ev_child>), and event
		78	watchers dealing with the event loop mechanism itself (C<ev_idle>,
		79	C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as
		80	file watchers (C<ev_stat>) and even limited support for fork events
		81	(C<ev_fork>).
		82
		83	It also is quite fast (see this
31	fast (see this L<benchmark\|http://libev.schmorp.de/bench.html> comparing	84	L<benchmark\|http://libev.schmorp.de/bench.html> comparing it to libevent
32	it to libevent for example).	85	for example).
33		86
34	=head1 CONVENTIONS	87	=head1 CONVENTIONS
35		88
36	Libev is very configurable. In this manual the default configuration	89	Libev is very configurable. In this manual the default configuration will
37	will be described, which supports multiple event loops. For more info	90	be described, which supports multiple event loops. For more info about
38	about various configuration options please have a look at the file	91	various configuration options please have a look at B<EMBED> section in
39	F<README.embed> in the libev distribution. If libev was configured without	92	this manual. If libev was configured without support for multiple event
40	support for multiple event loops, then all functions taking an initial	93	loops, then all functions taking an initial argument of name C<loop>
41	argument of name C<loop> (which is always of type C<struct ev_loop *>)	94	(which is always of type C<struct ev_loop *>) will not have this argument.
42	will not have this argument.
43		95
44	=head1 TIME REPRESENTATION	96	=head1 TIME REPRESENTATION
45		97
46	Libev represents time as a single floating point number, representing the	98	Libev represents time as a single floating point number, representing the
47	(fractional) number of seconds since the (POSIX) epoch (somewhere near	99	(fractional) number of seconds since the (POSIX) epoch (somewhere near
…		…
76	Usually, it's a good idea to terminate if the major versions mismatch,	128	Usually, it's a good idea to terminate if the major versions mismatch,
77	as this indicates an incompatible change. Minor versions are usually	129	as this indicates an incompatible change. Minor versions are usually
78	compatible to older versions, so a larger minor version alone is usually	130	compatible to older versions, so a larger minor version alone is usually
79	not a problem.	131	not a problem.
80		132
81	Example: make sure we haven't accidentally been linked against the wrong	133	Example: Make sure we haven't accidentally been linked against the wrong
82	version:	134	version.
83		135
84	assert (("libev version mismatch",	136	assert (("libev version mismatch",
85	ev_version_major () == EV_VERSION_MAJOR	137	ev_version_major () == EV_VERSION_MAJOR
86	&& ev_version_minor () >= EV_VERSION_MINOR));	138	&& ev_version_minor () >= EV_VERSION_MINOR));
87		139
…		…
115	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	167	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for
116	recommended ones.	168	recommended ones.
117		169
118	See the description of C<ev_embed> watchers for more info.	170	See the description of C<ev_embed> watchers for more info.
119		171
120	=item ev_set_allocator (void (cb)(void *ptr, size_t size))	172	=item ev_set_allocator (void (cb)(void *ptr, long size))
121		173
122	Sets the allocation function to use (the prototype and semantics are	174	Sets the allocation function to use (the prototype is similar - the
123	identical to the realloc C function). It is used to allocate and free	175	semantics is identical - to the realloc C function). It is used to
124	memory (no surprises here). If it returns zero when memory needs to be	176	allocate and free memory (no surprises here). If it returns zero when
125	allocated, the library might abort or take some potentially destructive	177	memory needs to be allocated, the library might abort or take some
126	action. The default is your system realloc function.	178	potentially destructive action. The default is your system realloc
		179	function.
127		180
128	You could override this function in high-availability programs to, say,	181	You could override this function in high-availability programs to, say,
129	free some memory if it cannot allocate memory, to use a special allocator,	182	free some memory if it cannot allocate memory, to use a special allocator,
130	or even to sleep a while and retry until some memory is available.	183	or even to sleep a while and retry until some memory is available.
131		184
132	Example: replace the libev allocator with one that waits a bit and then	185	Example: Replace the libev allocator with one that waits a bit and then
133	retries: better than mine).	186	retries).
134		187
135	static void *	188	static void *
136	persistent_realloc (void *ptr, size_t size)	189	persistent_realloc (void *ptr, size_t size)
137	{	190	{
138	for (;;)	191	for (;;)
…		…
157	callback is set, then libev will expect it to remedy the sitution, no	210	callback is set, then libev will expect it to remedy the sitution, no
158	matter what, when it returns. That is, libev will generally retry the	211	matter what, when it returns. That is, libev will generally retry the
159	requested operation, or, if the condition doesn't go away, do bad stuff	212	requested operation, or, if the condition doesn't go away, do bad stuff
160	(such as abort).	213	(such as abort).
161		214
162	Example: do the same thing as libev does internally:	215	Example: This is basically the same thing that libev does internally, too.
163		216
164	static void	217	static void
165	fatal_error (const char *msg)	218	fatal_error (const char *msg)
166	{	219	{
167	perror (msg);	220	perror (msg);
…		…
217	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will	270	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
218	override the flags completely if it is found in the environment. This is	271	override the flags completely if it is found in the environment. This is
219	useful to try out specific backends to test their performance, or to work	272	useful to try out specific backends to test their performance, or to work
220	around bugs.	273	around bugs.
221		274
		275	=item C<EVFLAG_FORKCHECK>
		276
		277	Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after
		278	a fork, you can also make libev check for a fork in each iteration by
		279	enabling this flag.
		280
		281	This works by calling C<getpid ()> on every iteration of the loop,
		282	and thus this might slow down your event loop if you do a lot of loop
		283	iterations and little real work, but is usually not noticeable (on my
		284	Linux system for example, C<getpid> is actually a simple 5-insn sequence
		285	without a syscall and thus I<very> fast, but my Linux system also has
		286	C<pthread_atfork> which is even faster).
		287
		288	The big advantage of this flag is that you can forget about fork (and
		289	forget about forgetting to tell libev about forking) when you use this
		290	flag.
		291
		292	This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS>
		293	environment variable.
		294
222	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	295	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
223		296
224	This is your standard select(2) backend. Not I<completely> standard, as	297	This is your standard select(2) backend. Not I<completely> standard, as
225	libev tries to roll its own fd_set with no limits on the number of fds,	298	libev tries to roll its own fd_set with no limits on the number of fds,
226	but if that fails, expect a fairly low limit on the number of fds when	299	but if that fails, expect a fairly low limit on the number of fds when
…		…
313	Similar to C<ev_default_loop>, but always creates a new event loop that is	386	Similar to C<ev_default_loop>, but always creates a new event loop that is
314	always distinct from the default loop. Unlike the default loop, it cannot	387	always distinct from the default loop. Unlike the default loop, it cannot
315	handle signal and child watchers, and attempts to do so will be greeted by	388	handle signal and child watchers, and attempts to do so will be greeted by
316	undefined behaviour (or a failed assertion if assertions are enabled).	389	undefined behaviour (or a failed assertion if assertions are enabled).
317		390
318	Example: try to create a event loop that uses epoll and nothing else.	391	Example: Try to create a event loop that uses epoll and nothing else.
319		392
320	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	393	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
321	if (!epoller)	394	if (!epoller)
322	fatal ("no epoll found here, maybe it hides under your chair");	395	fatal ("no epoll found here, maybe it hides under your chair");
323		396
…		…
360	=item ev_loop_fork (loop)	433	=item ev_loop_fork (loop)
361		434
362	Like C<ev_default_fork>, but acts on an event loop created by	435	Like C<ev_default_fork>, but acts on an event loop created by
363	C<ev_loop_new>. Yes, you have to call this on every allocated event loop	436	C<ev_loop_new>. Yes, you have to call this on every allocated event loop
364	after fork, and how you do this is entirely your own problem.	437	after fork, and how you do this is entirely your own problem.
		438
		439	=item unsigned int ev_loop_count (loop)
		440
		441	Returns the count of loop iterations for the loop, which is identical to
		442	the number of times libev did poll for new events. It starts at C<0> and
		443	happily wraps around with enough iterations.
		444
		445	This value can sometimes be useful as a generation counter of sorts (it
		446	"ticks" the number of loop iterations), as it roughly corresponds with
		447	C<ev_prepare> and C<ev_check> calls.
365		448
366	=item unsigned int ev_backend (loop)	449	=item unsigned int ev_backend (loop)
367		450
368	Returns one of the C<EVBACKEND_*> flags indicating the event backend in	451	Returns one of the C<EVBACKEND_*> flags indicating the event backend in
369	use.	452	use.
…		…
422	Signals and child watchers are implemented as I/O watchers, and will	505	Signals and child watchers are implemented as I/O watchers, and will
423	be handled here by queueing them when their watcher gets executed.	506	be handled here by queueing them when their watcher gets executed.
424	- If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	507	- If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
425	were used, return, otherwise continue with step *.	508	were used, return, otherwise continue with step *.
426		509
427	Example: queue some jobs and then loop until no events are outsanding	510	Example: Queue some jobs and then loop until no events are outsanding
428	anymore.	511	anymore.
429		512
430	... queue jobs here, make sure they register event watchers as long	513	... queue jobs here, make sure they register event watchers as long
431	... as they still have work to do (even an idle watcher will do..)	514	... as they still have work to do (even an idle watcher will do..)
432	ev_loop (my_loop, 0);	515	ev_loop (my_loop, 0);
…		…
452	visible to the libev user and should not keep C<ev_loop> from exiting if	535	visible to the libev user and should not keep C<ev_loop> from exiting if
453	no event watchers registered by it are active. It is also an excellent	536	no event watchers registered by it are active. It is also an excellent
454	way to do this for generic recurring timers or from within third-party	537	way to do this for generic recurring timers or from within third-party
455	libraries. Just remember to I<unref after start> and I<ref before stop>.	538	libraries. Just remember to I<unref after start> and I<ref before stop>.
456		539
457	Example: create a signal watcher, but keep it from keeping C<ev_loop>	540	Example: Create a signal watcher, but keep it from keeping C<ev_loop>
458	running when nothing else is active.	541	running when nothing else is active.
459		542
460	struct dv_signal exitsig;	543	struct ev_signal exitsig;
461	ev_signal_init (&exitsig, sig_cb, SIGINT);	544	ev_signal_init (&exitsig, sig_cb, SIGINT);
462	ev_signal_start (myloop, &exitsig);	545	ev_signal_start (loop, &exitsig);
463	evf_unref (myloop);	546	evf_unref (loop);
464		547
465	Example: for some weird reason, unregister the above signal handler again.	548	Example: For some weird reason, unregister the above signal handler again.
466		549
467	ev_ref (myloop);	550	ev_ref (loop);
468	ev_signal_stop (myloop, &exitsig);	551	ev_signal_stop (loop, &exitsig);
469		552
470	=back	553	=back
471		554
472		555
473	=head1 ANATOMY OF A WATCHER	556	=head1 ANATOMY OF A WATCHER
…		…
653	=item bool ev_is_pending (ev_TYPE *watcher)	736	=item bool ev_is_pending (ev_TYPE *watcher)
654		737
655	Returns a true value iff the watcher is pending, (i.e. it has outstanding	738	Returns a true value iff the watcher is pending, (i.e. it has outstanding
656	events but its callback has not yet been invoked). As long as a watcher	739	events but its callback has not yet been invoked). As long as a watcher
657	is pending (but not active) you must not call an init function on it (but	740	is pending (but not active) you must not call an init function on it (but
658	C<ev_TYPE_set> is safe) and you must make sure the watcher is available to	741	C<ev_TYPE_set> is safe), you must not change its priority, and you must
659	libev (e.g. you cnanot C<free ()> it).	742	make sure the watcher is available to libev (e.g. you cannot C<free ()>
		743	it).
660		744
661	=item callback = ev_cb (ev_TYPE *watcher)	745	=item callback ev_cb (ev_TYPE *watcher)
662		746
663	Returns the callback currently set on the watcher.	747	Returns the callback currently set on the watcher.
664		748
665	=item ev_cb_set (ev_TYPE *watcher, callback)	749	=item ev_cb_set (ev_TYPE *watcher, callback)
666		750
667	Change the callback. You can change the callback at virtually any time	751	Change the callback. You can change the callback at virtually any time
668	(modulo threads).	752	(modulo threads).
		753
		754	=item ev_set_priority (ev_TYPE *watcher, priority)
		755
		756	=item int ev_priority (ev_TYPE *watcher)
		757
		758	Set and query the priority of the watcher. The priority is a small
		759	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
		760	(default: C<-2>). Pending watchers with higher priority will be invoked
		761	before watchers with lower priority, but priority will not keep watchers
		762	from being executed (except for C<ev_idle> watchers).
		763
		764	This means that priorities are I<only> used for ordering callback
		765	invocation after new events have been received. This is useful, for
		766	example, to reduce latency after idling, or more often, to bind two
		767	watchers on the same event and make sure one is called first.
		768
		769	If you need to suppress invocation when higher priority events are pending
		770	you need to look at C<ev_idle> watchers, which provide this functionality.
		771
		772	You I<must not> change the priority of a watcher as long as it is active or
		773	pending.
		774
		775	The default priority used by watchers when no priority has been set is
		776	always C<0>, which is supposed to not be too high and not be too low :).
		777
		778	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
		779	fine, as long as you do not mind that the priority value you query might
		780	or might not have been adjusted to be within valid range.
		781
		782	=item ev_invoke (loop, ev_TYPE *watcher, int revents)
		783
		784	Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
		785	C<loop> nor C<revents> need to be valid as long as the watcher callback
		786	can deal with that fact.
		787
		788	=item int ev_clear_pending (loop, ev_TYPE *watcher)
		789
		790	If the watcher is pending, this function returns clears its pending status
		791	and returns its C<revents> bitset (as if its callback was invoked). If the
		792	watcher isn't pending it does nothing and returns C<0>.
669		793
670	=back	794	=back
671		795
672		796
673	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	797	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
694	{	818	{
695	struct my_io w = (struct my_io )w_;	819	struct my_io w = (struct my_io )w_;
696	...	820	...
697	}	821	}
698		822
699	More interesting and less C-conformant ways of catsing your callback type	823	More interesting and less C-conformant ways of casting your callback type
700	have been omitted....	824	instead have been omitted.
		825
		826	Another common scenario is having some data structure with multiple
		827	watchers:
		828
		829	struct my_biggy
		830	{
		831	int some_data;
		832	ev_timer t1;
		833	ev_timer t2;
		834	}
		835
		836	In this case getting the pointer to C<my_biggy> is a bit more complicated,
		837	you need to use C<offsetof>:
		838
		839	#include <stddef.h>
		840
		841	static void
		842	t1_cb (EV_P_ struct ev_timer *w, int revents)
		843	{
		844	struct my_biggy big = (struct my_biggy *
		845	(((char *)w) - offsetof (struct my_biggy, t1));
		846	}
		847
		848	static void
		849	t2_cb (EV_P_ struct ev_timer *w, int revents)
		850	{
		851	struct my_biggy big = (struct my_biggy *
		852	(((char *)w) - offsetof (struct my_biggy, t2));
		853	}
701		854
702		855
703	=head1 WATCHER TYPES	856	=head1 WATCHER TYPES
704		857
705	This section describes each watcher in detail, but will not repeat	858	This section describes each watcher in detail, but will not repeat
…		…
750	it is best to always use non-blocking I/O: An extra C<read>(2) returning	903	it is best to always use non-blocking I/O: An extra C<read>(2) returning
751	C<EAGAIN> is far preferable to a program hanging until some data arrives.	904	C<EAGAIN> is far preferable to a program hanging until some data arrives.
752		905
753	If you cannot run the fd in non-blocking mode (for example you should not	906	If you cannot run the fd in non-blocking mode (for example you should not
754	play around with an Xlib connection), then you have to seperately re-test	907	play around with an Xlib connection), then you have to seperately re-test
755	wether a file descriptor is really ready with a known-to-be good interface	908	whether a file descriptor is really ready with a known-to-be good interface
756	such as poll (fortunately in our Xlib example, Xlib already does this on	909	such as poll (fortunately in our Xlib example, Xlib already does this on
757	its own, so its quite safe to use).	910	its own, so its quite safe to use).
758		911
759	=over 4	912	=over 4
760		913
…		…
774		927
775	The events being watched.	928	The events being watched.
776		929
777	=back	930	=back
778		931
779	Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well	932	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
780	readable, but only once. Since it is likely line-buffered, you could	933	readable, but only once. Since it is likely line-buffered, you could
781	attempt to read a whole line in the callback:	934	attempt to read a whole line in the callback.
782		935
783	static void	936	static void
784	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	937	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
785	{	938	{
786	ev_io_stop (loop, w);	939	ev_io_stop (loop, w);
…		…
838	=item ev_timer_again (loop)	991	=item ev_timer_again (loop)
839		992
840	This will act as if the timer timed out and restart it again if it is	993	This will act as if the timer timed out and restart it again if it is
841	repeating. The exact semantics are:	994	repeating. The exact semantics are:
842		995
		996	If the timer is pending, its pending status is cleared.
		997
843	If the timer is started but nonrepeating, stop it.	998	If the timer is started but nonrepeating, stop it (as if it timed out).
844		999
845	If the timer is repeating, either start it if necessary (with the repeat	1000	If the timer is repeating, either start it if necessary (with the
846	value), or reset the running timer to the repeat value.	1001	C<repeat> value), or reset the running timer to the C<repeat> value.
847		1002
848	This sounds a bit complicated, but here is a useful and typical	1003	This sounds a bit complicated, but here is a useful and typical
849	example: Imagine you have a tcp connection and you want a so-called	1004	example: Imagine you have a tcp connection and you want a so-called idle
850	idle timeout, that is, you want to be called when there have been,	1005	timeout, that is, you want to be called when there have been, say, 60
851	say, 60 seconds of inactivity on the socket. The easiest way to do	1006	seconds of inactivity on the socket. The easiest way to do this is to
852	this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling	1007	configure an C<ev_timer> with a C<repeat> value of C<60> and then call
853	C<ev_timer_again> each time you successfully read or write some data. If	1008	C<ev_timer_again> each time you successfully read or write some data. If
854	you go into an idle state where you do not expect data to travel on the	1009	you go into an idle state where you do not expect data to travel on the
855	socket, you can stop the timer, and again will automatically restart it if	1010	socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will
856	need be.	1011	automatically restart it if need be.
857		1012
858	You can also ignore the C<after> value and C<ev_timer_start> altogether	1013	That means you can ignore the C<after> value and C<ev_timer_start>
859	and only ever use the C<repeat> value:	1014	altogether and only ever use the C<repeat> value and C<ev_timer_again>:
860		1015
861	ev_timer_init (timer, callback, 0., 5.);	1016	ev_timer_init (timer, callback, 0., 5.);
862	ev_timer_again (loop, timer);	1017	ev_timer_again (loop, timer);
863	...	1018	...
864	timer->again = 17.;	1019	timer->again = 17.;
865	ev_timer_again (loop, timer);	1020	ev_timer_again (loop, timer);
866	...	1021	...
867	timer->again = 10.;	1022	timer->again = 10.;
868	ev_timer_again (loop, timer);	1023	ev_timer_again (loop, timer);
869		1024
870	This is more efficient then stopping/starting the timer eahc time you want	1025	This is more slightly efficient then stopping/starting the timer each time
871	to modify its timeout value.	1026	you want to modify its timeout value.
872		1027
873	=item ev_tstamp repeat [read-write]	1028	=item ev_tstamp repeat [read-write]
874		1029
875	The current C<repeat> value. Will be used each time the watcher times out	1030	The current C<repeat> value. Will be used each time the watcher times out
876	or C<ev_timer_again> is called and determines the next timeout (if any),	1031	or C<ev_timer_again> is called and determines the next timeout (if any),
877	which is also when any modifications are taken into account.	1032	which is also when any modifications are taken into account.
878		1033
879	=back	1034	=back
880		1035
881	Example: create a timer that fires after 60 seconds.	1036	Example: Create a timer that fires after 60 seconds.
882		1037
883	static void	1038	static void
884	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1039	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
885	{	1040	{
886	.. one minute over, w is actually stopped right here	1041	.. one minute over, w is actually stopped right here
…		…
888		1043
889	struct ev_timer mytimer;	1044	struct ev_timer mytimer;
890	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1045	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
891	ev_timer_start (loop, &mytimer);	1046	ev_timer_start (loop, &mytimer);
892		1047
893	Example: create a timeout timer that times out after 10 seconds of	1048	Example: Create a timeout timer that times out after 10 seconds of
894	inactivity.	1049	inactivity.
895		1050
896	static void	1051	static void
897	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1052	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
898	{	1053	{
…		…
1023	switched off. Can be changed any time, but changes only take effect when	1178	switched off. Can be changed any time, but changes only take effect when
1024	the periodic timer fires or C<ev_periodic_again> is being called.	1179	the periodic timer fires or C<ev_periodic_again> is being called.
1025		1180
1026	=back	1181	=back
1027		1182
1028	Example: call a callback every hour, or, more precisely, whenever the	1183	Example: Call a callback every hour, or, more precisely, whenever the
1029	system clock is divisible by 3600. The callback invocation times have	1184	system clock is divisible by 3600. The callback invocation times have
1030	potentially a lot of jittering, but good long-term stability.	1185	potentially a lot of jittering, but good long-term stability.
1031		1186
1032	static void	1187	static void
1033	clock_cb (struct ev_loop loop, struct ev_io w, int revents)	1188	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
…		…
1037		1192
1038	struct ev_periodic hourly_tick;	1193	struct ev_periodic hourly_tick;
1039	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1194	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1040	ev_periodic_start (loop, &hourly_tick);	1195	ev_periodic_start (loop, &hourly_tick);
1041		1196
1042	Example: the same as above, but use a reschedule callback to do it:	1197	Example: The same as above, but use a reschedule callback to do it:
1043		1198
1044	#include <math.h>	1199	#include <math.h>
1045		1200
1046	static ev_tstamp	1201	static ev_tstamp
1047	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1202	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
…		…
1049	return fmod (now, 3600.) + 3600.;	1204	return fmod (now, 3600.) + 3600.;
1050	}	1205	}
1051		1206
1052	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1207	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1053		1208
1054	Example: call a callback every hour, starting now:	1209	Example: Call a callback every hour, starting now:
1055		1210
1056	struct ev_periodic hourly_tick;	1211	struct ev_periodic hourly_tick;
1057	ev_periodic_init (&hourly_tick, clock_cb,	1212	ev_periodic_init (&hourly_tick, clock_cb,
1058	fmod (ev_now (loop), 3600.), 3600., 0);	1213	fmod (ev_now (loop), 3600.), 3600., 0);
1059	ev_periodic_start (loop, &hourly_tick);	1214	ev_periodic_start (loop, &hourly_tick);
…		…
1120	The process exit/trace status caused by C<rpid> (see your systems	1275	The process exit/trace status caused by C<rpid> (see your systems
1121	C<waitpid> and C<sys/wait.h> documentation for details).	1276	C<waitpid> and C<sys/wait.h> documentation for details).
1122		1277
1123	=back	1278	=back
1124		1279
1125	Example: try to exit cleanly on SIGINT and SIGTERM.	1280	Example: Try to exit cleanly on SIGINT and SIGTERM.
1126		1281
1127	static void	1282	static void
1128	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1283	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1129	{	1284	{
1130	ev_unloop (loop, EVUNLOOP_ALL);	1285	ev_unloop (loop, EVUNLOOP_ALL);
…		…
1145	not exist" is a status change like any other. The condition "path does	1300	not exist" is a status change like any other. The condition "path does
1146	not exist" is signified by the C<st_nlink> field being zero (which is	1301	not exist" is signified by the C<st_nlink> field being zero (which is
1147	otherwise always forced to be at least one) and all the other fields of	1302	otherwise always forced to be at least one) and all the other fields of
1148	the stat buffer having unspecified contents.	1303	the stat buffer having unspecified contents.
1149		1304
		1305	The path I<should> be absolute and I<must not> end in a slash. If it is
		1306	relative and your working directory changes, the behaviour is undefined.
		1307
1150	Since there is no standard to do this, the portable implementation simply	1308	Since there is no standard to do this, the portable implementation simply
1151	calls C<stat (2)> regulalry on the path to see if it changed somehow. You	1309	calls C<stat (2)> regularly on the path to see if it changed somehow. You
1152	can specify a recommended polling interval for this case. If you specify	1310	can specify a recommended polling interval for this case. If you specify
1153	a polling interval of C<0> (highly recommended!) then a I<suitable,	1311	a polling interval of C<0> (highly recommended!) then a I<suitable,
1154	unspecified default> value will be used (which you can expect to be around	1312	unspecified default> value will be used (which you can expect to be around
1155	five seconds, although this might change dynamically). Libev will also	1313	five seconds, although this might change dynamically). Libev will also
1156	impose a minimum interval which is currently around C<0.1>, but thats	1314	impose a minimum interval which is currently around C<0.1>, but thats
…		…
1158		1316
1159	This watcher type is not meant for massive numbers of stat watchers,	1317	This watcher type is not meant for massive numbers of stat watchers,
1160	as even with OS-supported change notifications, this can be	1318	as even with OS-supported change notifications, this can be
1161	resource-intensive.	1319	resource-intensive.
1162		1320
1163	At the time of this writing, no specific OS backends are implemented, but	1321	At the time of this writing, only the Linux inotify interface is
1164	if demand increases, at least a kqueue and inotify backend will be added.	1322	implemented (implementing kqueue support is left as an exercise for the
		1323	reader). Inotify will be used to give hints only and should not change the
		1324	semantics of C<ev_stat> watchers, which means that libev sometimes needs
		1325	to fall back to regular polling again even with inotify, but changes are
		1326	usually detected immediately, and if the file exists there will be no
		1327	polling.
1165		1328
1166	=over 4	1329	=over 4
1167		1330
1168	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)	1331	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)
1169		1332
…		…
1233	ev_stat_start (loop, &passwd);	1396	ev_stat_start (loop, &passwd);
1234		1397
1235		1398
1236	=head2 C<ev_idle> - when you've got nothing better to do...	1399	=head2 C<ev_idle> - when you've got nothing better to do...
1237		1400
1238	Idle watchers trigger events when there are no other events are pending	1401	Idle watchers trigger events when no other events of the same or higher
1239	(prepare, check and other idle watchers do not count). That is, as long	1402	priority are pending (prepare, check and other idle watchers do not
1240	as your process is busy handling sockets or timeouts (or even signals,	1403	count).
1241	imagine) it will not be triggered. But when your process is idle all idle	1404
1242	watchers are being called again and again, once per event loop iteration -	1405	That is, as long as your process is busy handling sockets or timeouts
		1406	(or even signals, imagine) of the same or higher priority it will not be
		1407	triggered. But when your process is idle (or only lower-priority watchers
		1408	are pending), the idle watchers are being called once per event loop
1243	until stopped, that is, or your process receives more events and becomes	1409	iteration - until stopped, that is, or your process receives more events
1244	busy.	1410	and becomes busy again with higher priority stuff.
1245		1411
1246	The most noteworthy effect is that as long as any idle watchers are	1412	The most noteworthy effect is that as long as any idle watchers are
1247	active, the process will not block when waiting for new events.	1413	active, the process will not block when waiting for new events.
1248		1414
1249	Apart from keeping your process non-blocking (which is a useful	1415	Apart from keeping your process non-blocking (which is a useful
…		…
1259	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,	1425	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
1260	believe me.	1426	believe me.
1261		1427
1262	=back	1428	=back
1263		1429
1264	Example: dynamically allocate an C<ev_idle>, start it, and in the	1430	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1265	callback, free it. Alos, use no error checking, as usual.	1431	callback, free it. Also, use no error checking, as usual.
1266		1432
1267	static void	1433	static void
1268	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1434	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1269	{	1435	{
1270	free (w);	1436	free (w);
…		…
1349		1515
1350	// create io watchers for each fd and a timer before blocking	1516	// create io watchers for each fd and a timer before blocking
1351	static void	1517	static void
1352	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1518	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1353	{	1519	{
1354	int timeout = 3600000;truct pollfd fds [nfd];	1520	int timeout = 3600000;
		1521	struct pollfd fds [nfd];
1355	// actual code will need to loop here and realloc etc.	1522	// actual code will need to loop here and realloc etc.
1356	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1523	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1357		1524
1358	/* the callback is illegal, but won't be called as we stop during check */	1525	/* the callback is illegal, but won't be called as we stop during check */
1359	ev_timer_init (&tw, 0, timeout * 1e-3);	1526	ev_timer_init (&tw, 0, timeout * 1e-3);
…		…
1593		1760
1594	To use it,	1761	To use it,
1595		1762
1596	#include <ev++.h>	1763	#include <ev++.h>
1597		1764
1598	(it is not installed by default). This automatically includes F<ev.h>	1765	This automatically includes F<ev.h> and puts all of its definitions (many
1599	and puts all of its definitions (many of them macros) into the global	1766	of them macros) into the global namespace. All C++ specific things are
1600	namespace. All C++ specific things are put into the C<ev> namespace.	1767	put into the C<ev> namespace. It should support all the same embedding
		1768	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
1601		1769
1602	It should support all the same embedding options as F<ev.h>, most notably	1770	Care has been taken to keep the overhead low. The only data member the C++
1603	C<EV_MULTIPLICITY>.	1771	classes add (compared to plain C-style watchers) is the event loop pointer
		1772	that the watcher is associated with (or no additional members at all if
		1773	you disable C<EV_MULTIPLICITY> when embedding libev).
		1774
		1775	Currently, functions, and static and non-static member functions can be
		1776	used as callbacks. Other types should be easy to add as long as they only
		1777	need one additional pointer for context. If you need support for other
		1778	types of functors please contact the author (preferably after implementing
		1779	it).
1604		1780
1605	Here is a list of things available in the C<ev> namespace:	1781	Here is a list of things available in the C<ev> namespace:
1606		1782
1607	=over 4	1783	=over 4
1608		1784
…		…
1624		1800
1625	All of those classes have these methods:	1801	All of those classes have these methods:
1626		1802
1627	=over 4	1803	=over 4
1628		1804
1629	=item ev::TYPE::TYPE (object , object::method )	1805	=item ev::TYPE::TYPE ()
1630		1806
1631	=item ev::TYPE::TYPE (object , object::method , struct ev_loop *)	1807	=item ev::TYPE::TYPE (struct ev_loop *)
1632		1808
1633	=item ev::TYPE::~TYPE	1809	=item ev::TYPE::~TYPE
1634		1810
1635	The constructor takes a pointer to an object and a method pointer to	1811	The constructor (optionally) takes an event loop to associate the watcher
1636	the event handler callback to call in this class. The constructor calls	1812	with. If it is omitted, it will use C<EV_DEFAULT>.
1637	C<ev_init> for you, which means you have to call the C<set> method	1813
1638	before starting it. If you do not specify a loop then the constructor	1814	The constructor calls C<ev_init> for you, which means you have to call the
1639	automatically associates the default loop with this watcher.	1815	C<set> method before starting it.
		1816
		1817	It will not set a callback, however: You have to call the templated C<set>
		1818	method to set a callback before you can start the watcher.
		1819
		1820	(The reason why you have to use a method is a limitation in C++ which does
		1821	not allow explicit template arguments for constructors).
1640		1822
1641	The destructor automatically stops the watcher if it is active.	1823	The destructor automatically stops the watcher if it is active.
		1824
		1825	=item w->set<class, &class::method> (object *)
		1826
		1827	This method sets the callback method to call. The method has to have a
		1828	signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as
		1829	first argument and the C<revents> as second. The object must be given as
		1830	parameter and is stored in the C<data> member of the watcher.
		1831
		1832	This method synthesizes efficient thunking code to call your method from
		1833	the C callback that libev requires. If your compiler can inline your
		1834	callback (i.e. it is visible to it at the place of the C<set> call and
		1835	your compiler is good :), then the method will be fully inlined into the
		1836	thunking function, making it as fast as a direct C callback.
		1837
		1838	Example: simple class declaration and watcher initialisation
		1839
		1840	struct myclass
		1841	{
		1842	void io_cb (ev::io &w, int revents) { }
		1843	}
		1844
		1845	myclass obj;
		1846	ev::io iow;
		1847	iow.set <myclass, &myclass::io_cb> (&obj);
		1848
		1849	=item w->set (void (function)(watcher &w, int), void data = 0)
		1850
		1851	Also sets a callback, but uses a static method or plain function as
		1852	callback. The optional C<data> argument will be stored in the watcher's
		1853	C<data> member and is free for you to use.
		1854
		1855	See the method-C<set> above for more details.
1642		1856
1643	=item w->set (struct ev_loop *)	1857	=item w->set (struct ev_loop *)
1644		1858
1645	Associates a different C<struct ev_loop> with this watcher. You can only	1859	Associates a different C<struct ev_loop> with this watcher. You can only
1646	do this when the watcher is inactive (and not pending either).	1860	do this when the watcher is inactive (and not pending either).
1647		1861
1648	=item w->set ([args])	1862	=item w->set ([args])
1649		1863
1650	Basically the same as C<ev_TYPE_set>, with the same args. Must be	1864	Basically the same as C<ev_TYPE_set>, with the same args. Must be
1651	called at least once. Unlike the C counterpart, an active watcher gets	1865	called at least once. Unlike the C counterpart, an active watcher gets
1652	automatically stopped and restarted.	1866	automatically stopped and restarted when reconfiguring it with this
		1867	method.
1653		1868
1654	=item w->start ()	1869	=item w->start ()
1655		1870
1656	Starts the watcher. Note that there is no C<loop> argument as the	1871	Starts the watcher. Note that there is no C<loop> argument, as the
1657	constructor already takes the loop.	1872	constructor already stores the event loop.
1658		1873
1659	=item w->stop ()	1874	=item w->stop ()
1660		1875
1661	Stops the watcher if it is active. Again, no C<loop> argument.	1876	Stops the watcher if it is active. Again, no C<loop> argument.
1662		1877
…		…
1687		1902
1688	myclass ();	1903	myclass ();
1689	}	1904	}
1690		1905
1691	myclass::myclass (int fd)	1906	myclass::myclass (int fd)
1692	: io (this, &myclass::io_cb),
1693	idle (this, &myclass::idle_cb)
1694	{	1907	{
		1908	io .set <myclass, &myclass::io_cb > (this);
		1909	idle.set <myclass, &myclass::idle_cb> (this);
		1910
1695	io.start (fd, ev::READ);	1911	io.start (fd, ev::READ);
1696	}	1912	}
1697		1913
1698		1914
1699	=head1 MACRO MAGIC	1915	=head1 MACRO MAGIC
1700		1916
1701	Libev can be compiled with a variety of options, the most fundemantal is	1917	Libev can be compiled with a variety of options, the most fundemantal is
1702	C<EV_MULTIPLICITY>. This option determines wether (most) functions and	1918	C<EV_MULTIPLICITY>. This option determines whether (most) functions and
1703	callbacks have an initial C<struct ev_loop *> argument.	1919	callbacks have an initial C<struct ev_loop *> argument.
1704		1920
1705	To make it easier to write programs that cope with either variant, the	1921	To make it easier to write programs that cope with either variant, the
1706	following macros are defined:	1922	following macros are defined:
1707		1923
…		…
1740	Similar to the other two macros, this gives you the value of the default	1956	Similar to the other two macros, this gives you the value of the default
1741	loop, if multiple loops are supported ("ev loop default").	1957	loop, if multiple loops are supported ("ev loop default").
1742		1958
1743	=back	1959	=back
1744		1960
1745	Example: Declare and initialise a check watcher, working regardless of	1961	Example: Declare and initialise a check watcher, utilising the above
1746	wether multiple loops are supported or not.	1962	macros so it will work regardless of whether multiple loops are supported
		1963	or not.
1747		1964
1748	static void	1965	static void
1749	check_cb (EV_P_ ev_timer *w, int revents)	1966	check_cb (EV_P_ ev_timer *w, int revents)
1750	{	1967	{
1751	ev_check_stop (EV_A_ w);	1968	ev_check_stop (EV_A_ w);
…		…
1753		1970
1754	ev_check check;	1971	ev_check check;
1755	ev_check_init (&check, check_cb);	1972	ev_check_init (&check, check_cb);
1756	ev_check_start (EV_DEFAULT_ &check);	1973	ev_check_start (EV_DEFAULT_ &check);
1757	ev_loop (EV_DEFAULT_ 0);	1974	ev_loop (EV_DEFAULT_ 0);
1758
1759		1975
1760	=head1 EMBEDDING	1976	=head1 EMBEDDING
1761		1977
1762	Libev can (and often is) directly embedded into host	1978	Libev can (and often is) directly embedded into host
1763	applications. Examples of applications that embed it include the Deliantra	1979	applications. Examples of applications that embed it include the Deliantra
…		…
1803	ev_vars.h	2019	ev_vars.h
1804	ev_wrap.h	2020	ev_wrap.h
1805		2021
1806	ev_win32.c required on win32 platforms only	2022	ev_win32.c required on win32 platforms only
1807		2023
1808	ev_select.c only when select backend is enabled (which is by default)	2024	ev_select.c only when select backend is enabled (which is enabled by default)
1809	ev_poll.c only when poll backend is enabled (disabled by default)	2025	ev_poll.c only when poll backend is enabled (disabled by default)
1810	ev_epoll.c only when the epoll backend is enabled (disabled by default)	2026	ev_epoll.c only when the epoll backend is enabled (disabled by default)
1811	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	2027	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1812	ev_port.c only when the solaris port backend is enabled (disabled by default)	2028	ev_port.c only when the solaris port backend is enabled (disabled by default)
1813		2029
…		…
1938		2154
1939	=item EV_USE_DEVPOLL	2155	=item EV_USE_DEVPOLL
1940		2156
1941	reserved for future expansion, works like the USE symbols above.	2157	reserved for future expansion, works like the USE symbols above.
1942		2158
		2159	=item EV_USE_INOTIFY
		2160
		2161	If defined to be C<1>, libev will compile in support for the Linux inotify
		2162	interface to speed up C<ev_stat> watchers. Its actual availability will
		2163	be detected at runtime.
		2164
1943	=item EV_H	2165	=item EV_H
1944		2166
1945	The name of the F<ev.h> header file used to include it. The default if	2167	The name of the F<ev.h> header file used to include it. The default if
1946	undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This	2168	undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This
1947	can be used to virtually rename the F<ev.h> header file in case of conflicts.	2169	can be used to virtually rename the F<ev.h> header file in case of conflicts.
…		…
1970	will have the C<struct ev_loop *> as first argument, and you can create	2192	will have the C<struct ev_loop *> as first argument, and you can create
1971	additional independent event loops. Otherwise there will be no support	2193	additional independent event loops. Otherwise there will be no support
1972	for multiple event loops and there is no first event loop pointer	2194	for multiple event loops and there is no first event loop pointer
1973	argument. Instead, all functions act on the single default loop.	2195	argument. Instead, all functions act on the single default loop.
1974		2196
		2197	=item EV_MINPRI
		2198
		2199	=item EV_MAXPRI
		2200
		2201	The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
		2202	C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
		2203	provide for more priorities by overriding those symbols (usually defined
		2204	to be C<-2> and C<2>, respectively).
		2205
		2206	When doing priority-based operations, libev usually has to linearly search
		2207	all the priorities, so having many of them (hundreds) uses a lot of space
		2208	and time, so using the defaults of five priorities (-2 .. +2) is usually
		2209	fine.
		2210
		2211	If your embedding app does not need any priorities, defining these both to
		2212	C<0> will save some memory and cpu.
		2213
1975	=item EV_PERIODIC_ENABLE	2214	=item EV_PERIODIC_ENABLE
1976		2215
1977	If undefined or defined to be C<1>, then periodic timers are supported. If	2216	If undefined or defined to be C<1>, then periodic timers are supported. If
1978	defined to be C<0>, then they are not. Disabling them saves a few kB of	2217	defined to be C<0>, then they are not. Disabling them saves a few kB of
1979	code.	2218	code.
1980		2219
		2220	=item EV_IDLE_ENABLE
		2221
		2222	If undefined or defined to be C<1>, then idle watchers are supported. If
		2223	defined to be C<0>, then they are not. Disabling them saves a few kB of
		2224	code.
		2225
1981	=item EV_EMBED_ENABLE	2226	=item EV_EMBED_ENABLE
1982		2227
1983	If undefined or defined to be C<1>, then embed watchers are supported. If	2228	If undefined or defined to be C<1>, then embed watchers are supported. If
1984	defined to be C<0>, then they are not.	2229	defined to be C<0>, then they are not.
1985		2230
…		…
2002	=item EV_PID_HASHSIZE	2247	=item EV_PID_HASHSIZE
2003		2248
2004	C<ev_child> watchers use a small hash table to distribute workload by	2249	C<ev_child> watchers use a small hash table to distribute workload by
2005	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	2250	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more
2006	than enough. If you need to manage thousands of children you might want to	2251	than enough. If you need to manage thousands of children you might want to
2007	increase this value.	2252	increase this value (I<must> be a power of two).
		2253
		2254	=item EV_INOTIFY_HASHSIZE
		2255
		2256	C<ev_staz> watchers use a small hash table to distribute workload by
		2257	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),
		2258	usually more than enough. If you need to manage thousands of C<ev_stat>
		2259	watchers you might want to increase this value (I<must> be a power of
		2260	two).
2008		2261
2009	=item EV_COMMON	2262	=item EV_COMMON
2010		2263
2011	By default, all watchers have a C<void *data> member. By redefining	2264	By default, all watchers have a C<void *data> member. By redefining
2012	this macro to a something else you can include more and other types of	2265	this macro to a something else you can include more and other types of
…		…
2041	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file	2294	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file
2042	will be compiled. It is pretty complex because it provides its own header	2295	will be compiled. It is pretty complex because it provides its own header
2043	file.	2296	file.
2044		2297
2045	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	2298	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
2046	that everybody includes and which overrides some autoconf choices:	2299	that everybody includes and which overrides some configure choices:
2047		2300
		2301	#define EV_MINIMAL 1
2048	#define EV_USE_POLL 0	2302	#define EV_USE_POLL 0
2049	#define EV_MULTIPLICITY 0	2303	#define EV_MULTIPLICITY 0
2050	#define EV_PERIODICS 0	2304	#define EV_PERIODIC_ENABLE 0
		2305	#define EV_STAT_ENABLE 0
		2306	#define EV_FORK_ENABLE 0
2051	#define EV_CONFIG_H <config.h>	2307	#define EV_CONFIG_H <config.h>
		2308	#define EV_MINPRI 0
		2309	#define EV_MAXPRI 0
2052		2310
2053	#include "ev++.h"	2311	#include "ev++.h"
2054		2312
2055	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	2313	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
2056		2314
…		…
2062		2320
2063	In this section the complexities of (many of) the algorithms used inside	2321	In this section the complexities of (many of) the algorithms used inside
2064	libev will be explained. For complexity discussions about backends see the	2322	libev will be explained. For complexity discussions about backends see the
2065	documentation for C<ev_default_init>.	2323	documentation for C<ev_default_init>.
2066		2324
		2325	All of the following are about amortised time: If an array needs to be
		2326	extended, libev needs to realloc and move the whole array, but this
		2327	happens asymptotically never with higher number of elements, so O(1) might
		2328	mean it might do a lengthy realloc operation in rare cases, but on average
		2329	it is much faster and asymptotically approaches constant time.
		2330
2067	=over 4	2331	=over 4
2068		2332
2069	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	2333	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
2070		2334
		2335	This means that, when you have a watcher that triggers in one hour and
		2336	there are 100 watchers that would trigger before that then inserting will
		2337	have to skip those 100 watchers.
		2338
2071	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)	2339	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)
2072		2340
		2341	That means that for changing a timer costs less than removing/adding them
		2342	as only the relative motion in the event queue has to be paid for.
		2343
2073	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2344	=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2074		2345
		2346	These just add the watcher into an array or at the head of a list.
2075	=item Stopping check/prepare/idle watchers: O(1)	2347	=item Stopping check/prepare/idle watchers: O(1)
2076		2348
2077	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))	2349	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
		2350
		2351	These watchers are stored in lists then need to be walked to find the
		2352	correct watcher to remove. The lists are usually short (you don't usually
		2353	have many watchers waiting for the same fd or signal).
2078		2354
2079	=item Finding the next timer per loop iteration: O(1)	2355	=item Finding the next timer per loop iteration: O(1)
2080		2356
2081	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	2357	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2082		2358
		2359	A change means an I/O watcher gets started or stopped, which requires
		2360	libev to recalculate its status (and possibly tell the kernel).
		2361
2083	=item Activating one watcher: O(1)	2362	=item Activating one watcher: O(1)
2084		2363
		2364	=item Priority handling: O(number_of_priorities)
		2365
		2366	Priorities are implemented by allocating some space for each
		2367	priority. When doing priority-based operations, libev usually has to
		2368	linearly search all the priorities.
		2369
2085	=back	2370	=back
2086		2371
2087		2372
2088	=head1 AUTHOR	2373	=head1 AUTHOR
2089		2374

Diff Legend

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

Comparing libev/ev.pod (file contents): Revision 1.52 by root, Tue Nov 27 19:41:52 2007 UTC vs. Revision 1.74 by root, Sat Dec 8 14:12:08 2007 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.52 by root, Tue Nov 27 19:41:52 2007 UTC vs.
Revision 1.74 by root, Sat Dec 8 14:12:08 2007 UTC