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

Comparing libev/ev.pod (file contents):
Revision 1.53 by root, Tue Nov 27 20:15:02 2007 UTC vs.
Revision 1.73 by root, Sat Dec 8 03:53:36 2007 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	/* this is the only header you need */
8	#include <ev.h>	7	#include <ev.h>
9		8
10	/* what follows is a fully working example program */	9	=head1 EXAMPLE PROGRAM
		10
		11	#include <ev.h>
		12
11	ev_io stdin_watcher;	13	ev_io stdin_watcher;
12	ev_timer timeout_watcher;	14	ev_timer timeout_watcher;
13		15
14	/* called when data readable on stdin */	16	/* called when data readable on stdin */
15	static void	17	static void
…		…
45		47
46	return 0;	48	return 0;
47	}	49	}
48		50
49	=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>.
50		56
51	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
52	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
53	these event sources and provide your program with events.	59	these event sources and provide your program with events.
54		60
…		…
61	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
62	watcher.	68	watcher.
63		69
64	=head1 FEATURES	70	=head1 FEATURES
65		71
66	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
67	kqueue mechanisms for file descriptor events, relative timers, absolute	73	BSD-specific C<kqueue> and the Solaris-specific event port mechanisms
68	timers with customised rescheduling, signal events, process status change	74	for file descriptor events (C<ev_io>), the Linux C<inotify> interface
69	events (related to SIGCHLD), and event watchers dealing with the event	75	(for C<ev_stat>), relative timers (C<ev_timer>), absolute timers
70	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
71	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
72	it to libevent for example).	85	for example).
73		86
74	=head1 CONVENTIONS	87	=head1 CONVENTIONS
75		88
76	Libev is very configurable. In this manual the default configuration	89	Libev is very configurable. In this manual the default configuration will
77	will be described, which supports multiple event loops. For more info	90	be described, which supports multiple event loops. For more info about
78	about various configuration options please have a look at the file	91	various configuration options please have a look at B<EMBED> section in
79	F<README.embed> in the libev distribution. If libev was configured without	92	this manual. If libev was configured without support for multiple event
80	support for multiple event loops, then all functions taking an initial	93	loops, then all functions taking an initial argument of name C<loop>
81	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.
82	will not have this argument.
83		95
84	=head1 TIME REPRESENTATION	96	=head1 TIME REPRESENTATION
85		97
86	Libev represents time as a single floating point number, representing the	98	Libev represents time as a single floating point number, representing the
87	(fractional) number of seconds since the (POSIX) epoch (somewhere near	99	(fractional) number of seconds since the (POSIX) epoch (somewhere near
…		…
116	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,
117	as this indicates an incompatible change. Minor versions are usually	129	as this indicates an incompatible change. Minor versions are usually
118	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
119	not a problem.	131	not a problem.
120		132
121	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
122	version:	134	version.
123		135
124	assert (("libev version mismatch",	136	assert (("libev version mismatch",
125	ev_version_major () == EV_VERSION_MAJOR	137	ev_version_major () == EV_VERSION_MAJOR
126	&& ev_version_minor () >= EV_VERSION_MINOR));	138	&& ev_version_minor () >= EV_VERSION_MINOR));
127		139
…		…
155	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for	167	C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for
156	recommended ones.	168	recommended ones.
157		169
158	See the description of C<ev_embed> watchers for more info.	170	See the description of C<ev_embed> watchers for more info.
159		171
160	=item ev_set_allocator (void (cb)(void *ptr, size_t size))	172	=item ev_set_allocator (void (cb)(void *ptr, long size))
161		173
162	Sets the allocation function to use (the prototype and semantics are	174	Sets the allocation function to use (the prototype is similar - the
163	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
164	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
165	allocated, the library might abort or take some potentially destructive	177	memory needs to be allocated, the library might abort or take some
166	action. The default is your system realloc function.	178	potentially destructive action. The default is your system realloc
		179	function.
167		180
168	You could override this function in high-availability programs to, say,	181	You could override this function in high-availability programs to, say,
169	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,
170	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.
171		184
172	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
173	retries: better than mine).	186	retries).
174		187
175	static void *	188	static void *
176	persistent_realloc (void *ptr, size_t size)	189	persistent_realloc (void *ptr, size_t size)
177	{	190	{
178	for (;;)	191	for (;;)
…		…
197	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
198	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
199	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
200	(such as abort).	213	(such as abort).
201		214
202	Example: do the same thing as libev does internally:	215	Example: This is basically the same thing that libev does internally, too.
203		216
204	static void	217	static void
205	fatal_error (const char *msg)	218	fatal_error (const char *msg)
206	{	219	{
207	perror (msg);	220	perror (msg);
…		…
257	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will	270	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
258	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
259	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
260	around bugs.	273	around bugs.
261		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
262	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	295	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
263		296
264	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
265	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,
266	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
…		…
353	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
354	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
355	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
356	undefined behaviour (or a failed assertion if assertions are enabled).	389	undefined behaviour (or a failed assertion if assertions are enabled).
357		390
358	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.
359		392
360	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	393	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
361	if (!epoller)	394	if (!epoller)
362	fatal ("no epoll found here, maybe it hides under your chair");	395	fatal ("no epoll found here, maybe it hides under your chair");
363		396
…		…
400	=item ev_loop_fork (loop)	433	=item ev_loop_fork (loop)
401		434
402	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
403	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
404	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.
405		448
406	=item unsigned int ev_backend (loop)	449	=item unsigned int ev_backend (loop)
407		450
408	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
409	use.	452	use.
…		…
462	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
463	be handled here by queueing them when their watcher gets executed.	506	be handled here by queueing them when their watcher gets executed.
464	- 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
465	were used, return, otherwise continue with step *.	508	were used, return, otherwise continue with step *.
466		509
467	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
468	anymore.	511	anymore.
469		512
470	... queue jobs here, make sure they register event watchers as long	513	... queue jobs here, make sure they register event watchers as long
471	... 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..)
472	ev_loop (my_loop, 0);	515	ev_loop (my_loop, 0);
…		…
492	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
493	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
494	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
495	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>.
496		539
497	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>
498	running when nothing else is active.	541	running when nothing else is active.
499		542
500	struct dv_signal exitsig;	543	struct ev_signal exitsig;
501	ev_signal_init (&exitsig, sig_cb, SIGINT);	544	ev_signal_init (&exitsig, sig_cb, SIGINT);
502	ev_signal_start (myloop, &exitsig);	545	ev_signal_start (loop, &exitsig);
503	evf_unref (myloop);	546	evf_unref (loop);
504		547
505	Example: for some weird reason, unregister the above signal handler again.	548	Example: For some weird reason, unregister the above signal handler again.
506		549
507	ev_ref (myloop);	550	ev_ref (loop);
508	ev_signal_stop (myloop, &exitsig);	551	ev_signal_stop (loop, &exitsig);
509		552
510	=back	553	=back
511		554
512		555
513	=head1 ANATOMY OF A WATCHER	556	=head1 ANATOMY OF A WATCHER
…		…
693	=item bool ev_is_pending (ev_TYPE *watcher)	736	=item bool ev_is_pending (ev_TYPE *watcher)
694		737
695	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
696	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
697	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
698	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
699	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).
700		744
701	=item callback = ev_cb (ev_TYPE *watcher)	745	=item callback ev_cb (ev_TYPE *watcher)
702		746
703	Returns the callback currently set on the watcher.	747	Returns the callback currently set on the watcher.
704		748
705	=item ev_cb_set (ev_TYPE *watcher, callback)	749	=item ev_cb_set (ev_TYPE *watcher, callback)
706		750
707	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
708	(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.
709		781
710	=back	782	=back
711		783
712		784
713	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	785	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
734	{	806	{
735	struct my_io w = (struct my_io )w_;	807	struct my_io w = (struct my_io )w_;
736	...	808	...
737	}	809	}
738		810
739	More interesting and less C-conformant ways of catsing your callback type	811	More interesting and less C-conformant ways of casting your callback type
740	have been omitted....	812	instead have been omitted.
		813
		814	Another common scenario is having some data structure with multiple
		815	watchers:
		816
		817	struct my_biggy
		818	{
		819	int some_data;
		820	ev_timer t1;
		821	ev_timer t2;
		822	}
		823
		824	In this case getting the pointer to C<my_biggy> is a bit more complicated,
		825	you need to use C<offsetof>:
		826
		827	#include <stddef.h>
		828
		829	static void
		830	t1_cb (EV_P_ struct ev_timer *w, int revents)
		831	{
		832	struct my_biggy big = (struct my_biggy *
		833	(((char *)w) - offsetof (struct my_biggy, t1));
		834	}
		835
		836	static void
		837	t2_cb (EV_P_ struct ev_timer *w, int revents)
		838	{
		839	struct my_biggy big = (struct my_biggy *
		840	(((char *)w) - offsetof (struct my_biggy, t2));
		841	}
741		842
742		843
743	=head1 WATCHER TYPES	844	=head1 WATCHER TYPES
744		845
745	This section describes each watcher in detail, but will not repeat	846	This section describes each watcher in detail, but will not repeat
…		…
790	it is best to always use non-blocking I/O: An extra C<read>(2) returning	891	it is best to always use non-blocking I/O: An extra C<read>(2) returning
791	C<EAGAIN> is far preferable to a program hanging until some data arrives.	892	C<EAGAIN> is far preferable to a program hanging until some data arrives.
792		893
793	If you cannot run the fd in non-blocking mode (for example you should not	894	If you cannot run the fd in non-blocking mode (for example you should not
794	play around with an Xlib connection), then you have to seperately re-test	895	play around with an Xlib connection), then you have to seperately re-test
795	wether a file descriptor is really ready with a known-to-be good interface	896	whether a file descriptor is really ready with a known-to-be good interface
796	such as poll (fortunately in our Xlib example, Xlib already does this on	897	such as poll (fortunately in our Xlib example, Xlib already does this on
797	its own, so its quite safe to use).	898	its own, so its quite safe to use).
798		899
799	=over 4	900	=over 4
800		901
…		…
814		915
815	The events being watched.	916	The events being watched.
816		917
817	=back	918	=back
818		919
819	Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well	920	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
820	readable, but only once. Since it is likely line-buffered, you could	921	readable, but only once. Since it is likely line-buffered, you could
821	attempt to read a whole line in the callback:	922	attempt to read a whole line in the callback.
822		923
823	static void	924	static void
824	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	925	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
825	{	926	{
826	ev_io_stop (loop, w);	927	ev_io_stop (loop, w);
…		…
878	=item ev_timer_again (loop)	979	=item ev_timer_again (loop)
879		980
880	This will act as if the timer timed out and restart it again if it is	981	This will act as if the timer timed out and restart it again if it is
881	repeating. The exact semantics are:	982	repeating. The exact semantics are:
882		983
		984	If the timer is pending, its pending status is cleared.
		985
883	If the timer is started but nonrepeating, stop it.	986	If the timer is started but nonrepeating, stop it (as if it timed out).
884		987
885	If the timer is repeating, either start it if necessary (with the repeat	988	If the timer is repeating, either start it if necessary (with the
886	value), or reset the running timer to the repeat value.	989	C<repeat> value), or reset the running timer to the C<repeat> value.
887		990
888	This sounds a bit complicated, but here is a useful and typical	991	This sounds a bit complicated, but here is a useful and typical
889	example: Imagine you have a tcp connection and you want a so-called	992	example: Imagine you have a tcp connection and you want a so-called idle
890	idle timeout, that is, you want to be called when there have been,	993	timeout, that is, you want to be called when there have been, say, 60
891	say, 60 seconds of inactivity on the socket. The easiest way to do	994	seconds of inactivity on the socket. The easiest way to do this is to
892	this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling	995	configure an C<ev_timer> with a C<repeat> value of C<60> and then call
893	C<ev_timer_again> each time you successfully read or write some data. If	996	C<ev_timer_again> each time you successfully read or write some data. If
894	you go into an idle state where you do not expect data to travel on the	997	you go into an idle state where you do not expect data to travel on the
895	socket, you can stop the timer, and again will automatically restart it if	998	socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will
896	need be.	999	automatically restart it if need be.
897		1000
898	You can also ignore the C<after> value and C<ev_timer_start> altogether	1001	That means you can ignore the C<after> value and C<ev_timer_start>
899	and only ever use the C<repeat> value:	1002	altogether and only ever use the C<repeat> value and C<ev_timer_again>:
900		1003
901	ev_timer_init (timer, callback, 0., 5.);	1004	ev_timer_init (timer, callback, 0., 5.);
902	ev_timer_again (loop, timer);	1005	ev_timer_again (loop, timer);
903	...	1006	...
904	timer->again = 17.;	1007	timer->again = 17.;
905	ev_timer_again (loop, timer);	1008	ev_timer_again (loop, timer);
906	...	1009	...
907	timer->again = 10.;	1010	timer->again = 10.;
908	ev_timer_again (loop, timer);	1011	ev_timer_again (loop, timer);
909		1012
910	This is more efficient then stopping/starting the timer eahc time you want	1013	This is more slightly efficient then stopping/starting the timer each time
911	to modify its timeout value.	1014	you want to modify its timeout value.
912		1015
913	=item ev_tstamp repeat [read-write]	1016	=item ev_tstamp repeat [read-write]
914		1017
915	The current C<repeat> value. Will be used each time the watcher times out	1018	The current C<repeat> value. Will be used each time the watcher times out
916	or C<ev_timer_again> is called and determines the next timeout (if any),	1019	or C<ev_timer_again> is called and determines the next timeout (if any),
917	which is also when any modifications are taken into account.	1020	which is also when any modifications are taken into account.
918		1021
919	=back	1022	=back
920		1023
921	Example: create a timer that fires after 60 seconds.	1024	Example: Create a timer that fires after 60 seconds.
922		1025
923	static void	1026	static void
924	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1027	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
925	{	1028	{
926	.. one minute over, w is actually stopped right here	1029	.. one minute over, w is actually stopped right here
…		…
928		1031
929	struct ev_timer mytimer;	1032	struct ev_timer mytimer;
930	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1033	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
931	ev_timer_start (loop, &mytimer);	1034	ev_timer_start (loop, &mytimer);
932		1035
933	Example: create a timeout timer that times out after 10 seconds of	1036	Example: Create a timeout timer that times out after 10 seconds of
934	inactivity.	1037	inactivity.
935		1038
936	static void	1039	static void
937	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1040	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
938	{	1041	{
…		…
1063	switched off. Can be changed any time, but changes only take effect when	1166	switched off. Can be changed any time, but changes only take effect when
1064	the periodic timer fires or C<ev_periodic_again> is being called.	1167	the periodic timer fires or C<ev_periodic_again> is being called.
1065		1168
1066	=back	1169	=back
1067		1170
1068	Example: call a callback every hour, or, more precisely, whenever the	1171	Example: Call a callback every hour, or, more precisely, whenever the
1069	system clock is divisible by 3600. The callback invocation times have	1172	system clock is divisible by 3600. The callback invocation times have
1070	potentially a lot of jittering, but good long-term stability.	1173	potentially a lot of jittering, but good long-term stability.
1071		1174
1072	static void	1175	static void
1073	clock_cb (struct ev_loop loop, struct ev_io w, int revents)	1176	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
…		…
1077		1180
1078	struct ev_periodic hourly_tick;	1181	struct ev_periodic hourly_tick;
1079	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1182	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1080	ev_periodic_start (loop, &hourly_tick);	1183	ev_periodic_start (loop, &hourly_tick);
1081		1184
1082	Example: the same as above, but use a reschedule callback to do it:	1185	Example: The same as above, but use a reschedule callback to do it:
1083		1186
1084	#include <math.h>	1187	#include <math.h>
1085		1188
1086	static ev_tstamp	1189	static ev_tstamp
1087	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1190	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
…		…
1089	return fmod (now, 3600.) + 3600.;	1192	return fmod (now, 3600.) + 3600.;
1090	}	1193	}
1091		1194
1092	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1195	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1093		1196
1094	Example: call a callback every hour, starting now:	1197	Example: Call a callback every hour, starting now:
1095		1198
1096	struct ev_periodic hourly_tick;	1199	struct ev_periodic hourly_tick;
1097	ev_periodic_init (&hourly_tick, clock_cb,	1200	ev_periodic_init (&hourly_tick, clock_cb,
1098	fmod (ev_now (loop), 3600.), 3600., 0);	1201	fmod (ev_now (loop), 3600.), 3600., 0);
1099	ev_periodic_start (loop, &hourly_tick);	1202	ev_periodic_start (loop, &hourly_tick);
…		…
1160	The process exit/trace status caused by C<rpid> (see your systems	1263	The process exit/trace status caused by C<rpid> (see your systems
1161	C<waitpid> and C<sys/wait.h> documentation for details).	1264	C<waitpid> and C<sys/wait.h> documentation for details).
1162		1265
1163	=back	1266	=back
1164		1267
1165	Example: try to exit cleanly on SIGINT and SIGTERM.	1268	Example: Try to exit cleanly on SIGINT and SIGTERM.
1166		1269
1167	static void	1270	static void
1168	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1271	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1169	{	1272	{
1170	ev_unloop (loop, EVUNLOOP_ALL);	1273	ev_unloop (loop, EVUNLOOP_ALL);
…		…
1185	not exist" is a status change like any other. The condition "path does	1288	not exist" is a status change like any other. The condition "path does
1186	not exist" is signified by the C<st_nlink> field being zero (which is	1289	not exist" is signified by the C<st_nlink> field being zero (which is
1187	otherwise always forced to be at least one) and all the other fields of	1290	otherwise always forced to be at least one) and all the other fields of
1188	the stat buffer having unspecified contents.	1291	the stat buffer having unspecified contents.
1189		1292
		1293	The path I<should> be absolute and I<must not> end in a slash. If it is
		1294	relative and your working directory changes, the behaviour is undefined.
		1295
1190	Since there is no standard to do this, the portable implementation simply	1296	Since there is no standard to do this, the portable implementation simply
1191	calls C<stat (2)> regulalry on the path to see if it changed somehow. You	1297	calls C<stat (2)> regularly on the path to see if it changed somehow. You
1192	can specify a recommended polling interval for this case. If you specify	1298	can specify a recommended polling interval for this case. If you specify
1193	a polling interval of C<0> (highly recommended!) then a I<suitable,	1299	a polling interval of C<0> (highly recommended!) then a I<suitable,
1194	unspecified default> value will be used (which you can expect to be around	1300	unspecified default> value will be used (which you can expect to be around
1195	five seconds, although this might change dynamically). Libev will also	1301	five seconds, although this might change dynamically). Libev will also
1196	impose a minimum interval which is currently around C<0.1>, but thats	1302	impose a minimum interval which is currently around C<0.1>, but thats
…		…
1198		1304
1199	This watcher type is not meant for massive numbers of stat watchers,	1305	This watcher type is not meant for massive numbers of stat watchers,
1200	as even with OS-supported change notifications, this can be	1306	as even with OS-supported change notifications, this can be
1201	resource-intensive.	1307	resource-intensive.
1202		1308
1203	At the time of this writing, no specific OS backends are implemented, but	1309	At the time of this writing, only the Linux inotify interface is
1204	if demand increases, at least a kqueue and inotify backend will be added.	1310	implemented (implementing kqueue support is left as an exercise for the
		1311	reader). Inotify will be used to give hints only and should not change the
		1312	semantics of C<ev_stat> watchers, which means that libev sometimes needs
		1313	to fall back to regular polling again even with inotify, but changes are
		1314	usually detected immediately, and if the file exists there will be no
		1315	polling.
1205		1316
1206	=over 4	1317	=over 4
1207		1318
1208	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)	1319	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)
1209		1320
…		…
1273	ev_stat_start (loop, &passwd);	1384	ev_stat_start (loop, &passwd);
1274		1385
1275		1386
1276	=head2 C<ev_idle> - when you've got nothing better to do...	1387	=head2 C<ev_idle> - when you've got nothing better to do...
1277		1388
1278	Idle watchers trigger events when there are no other events are pending	1389	Idle watchers trigger events when no other events of the same or higher
1279	(prepare, check and other idle watchers do not count). That is, as long	1390	priority are pending (prepare, check and other idle watchers do not
1280	as your process is busy handling sockets or timeouts (or even signals,	1391	count).
1281	imagine) it will not be triggered. But when your process is idle all idle	1392
1282	watchers are being called again and again, once per event loop iteration -	1393	That is, as long as your process is busy handling sockets or timeouts
		1394	(or even signals, imagine) of the same or higher priority it will not be
		1395	triggered. But when your process is idle (or only lower-priority watchers
		1396	are pending), the idle watchers are being called once per event loop
1283	until stopped, that is, or your process receives more events and becomes	1397	iteration - until stopped, that is, or your process receives more events
1284	busy.	1398	and becomes busy again with higher priority stuff.
1285		1399
1286	The most noteworthy effect is that as long as any idle watchers are	1400	The most noteworthy effect is that as long as any idle watchers are
1287	active, the process will not block when waiting for new events.	1401	active, the process will not block when waiting for new events.
1288		1402
1289	Apart from keeping your process non-blocking (which is a useful	1403	Apart from keeping your process non-blocking (which is a useful
…		…
1299	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,	1413	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
1300	believe me.	1414	believe me.
1301		1415
1302	=back	1416	=back
1303		1417
1304	Example: dynamically allocate an C<ev_idle>, start it, and in the	1418	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1305	callback, free it. Alos, use no error checking, as usual.	1419	callback, free it. Also, use no error checking, as usual.
1306		1420
1307	static void	1421	static void
1308	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1422	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1309	{	1423	{
1310	free (w);	1424	free (w);
…		…
1389		1503
1390	// create io watchers for each fd and a timer before blocking	1504	// create io watchers for each fd and a timer before blocking
1391	static void	1505	static void
1392	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1506	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1393	{	1507	{
1394	int timeout = 3600000;truct pollfd fds [nfd];	1508	int timeout = 3600000;
		1509	struct pollfd fds [nfd];
1395	// actual code will need to loop here and realloc etc.	1510	// actual code will need to loop here and realloc etc.
1396	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1511	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1397		1512
1398	/* the callback is illegal, but won't be called as we stop during check */	1513	/* the callback is illegal, but won't be called as we stop during check */
1399	ev_timer_init (&tw, 0, timeout * 1e-3);	1514	ev_timer_init (&tw, 0, timeout * 1e-3);
…		…
1633		1748
1634	To use it,	1749	To use it,
1635		1750
1636	#include <ev++.h>	1751	#include <ev++.h>
1637		1752
1638	(it is not installed by default). This automatically includes F<ev.h>	1753	This automatically includes F<ev.h> and puts all of its definitions (many
1639	and puts all of its definitions (many of them macros) into the global	1754	of them macros) into the global namespace. All C++ specific things are
1640	namespace. All C++ specific things are put into the C<ev> namespace.	1755	put into the C<ev> namespace. It should support all the same embedding
		1756	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
1641		1757
1642	It should support all the same embedding options as F<ev.h>, most notably	1758	Care has been taken to keep the overhead low. The only data member the C++
1643	C<EV_MULTIPLICITY>.	1759	classes add (compared to plain C-style watchers) is the event loop pointer
		1760	that the watcher is associated with (or no additional members at all if
		1761	you disable C<EV_MULTIPLICITY> when embedding libev).
		1762
		1763	Currently, functions, and static and non-static member functions can be
		1764	used as callbacks. Other types should be easy to add as long as they only
		1765	need one additional pointer for context. If you need support for other
		1766	types of functors please contact the author (preferably after implementing
		1767	it).
1644		1768
1645	Here is a list of things available in the C<ev> namespace:	1769	Here is a list of things available in the C<ev> namespace:
1646		1770
1647	=over 4	1771	=over 4
1648		1772
…		…
1664		1788
1665	All of those classes have these methods:	1789	All of those classes have these methods:
1666		1790
1667	=over 4	1791	=over 4
1668		1792
1669	=item ev::TYPE::TYPE (object , object::method )	1793	=item ev::TYPE::TYPE ()
1670		1794
1671	=item ev::TYPE::TYPE (object , object::method , struct ev_loop *)	1795	=item ev::TYPE::TYPE (struct ev_loop *)
1672		1796
1673	=item ev::TYPE::~TYPE	1797	=item ev::TYPE::~TYPE
1674		1798
1675	The constructor takes a pointer to an object and a method pointer to	1799	The constructor (optionally) takes an event loop to associate the watcher
1676	the event handler callback to call in this class. The constructor calls	1800	with. If it is omitted, it will use C<EV_DEFAULT>.
1677	C<ev_init> for you, which means you have to call the C<set> method	1801
1678	before starting it. If you do not specify a loop then the constructor	1802	The constructor calls C<ev_init> for you, which means you have to call the
1679	automatically associates the default loop with this watcher.	1803	C<set> method before starting it.
		1804
		1805	It will not set a callback, however: You have to call the templated C<set>
		1806	method to set a callback before you can start the watcher.
		1807
		1808	(The reason why you have to use a method is a limitation in C++ which does
		1809	not allow explicit template arguments for constructors).
1680		1810
1681	The destructor automatically stops the watcher if it is active.	1811	The destructor automatically stops the watcher if it is active.
		1812
		1813	=item w->set<class, &class::method> (object *)
		1814
		1815	This method sets the callback method to call. The method has to have a
		1816	signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as
		1817	first argument and the C<revents> as second. The object must be given as
		1818	parameter and is stored in the C<data> member of the watcher.
		1819
		1820	This method synthesizes efficient thunking code to call your method from
		1821	the C callback that libev requires. If your compiler can inline your
		1822	callback (i.e. it is visible to it at the place of the C<set> call and
		1823	your compiler is good :), then the method will be fully inlined into the
		1824	thunking function, making it as fast as a direct C callback.
		1825
		1826	Example: simple class declaration and watcher initialisation
		1827
		1828	struct myclass
		1829	{
		1830	void io_cb (ev::io &w, int revents) { }
		1831	}
		1832
		1833	myclass obj;
		1834	ev::io iow;
		1835	iow.set <myclass, &myclass::io_cb> (&obj);
		1836
		1837	=item w->set (void (function)(watcher &w, int), void data = 0)
		1838
		1839	Also sets a callback, but uses a static method or plain function as
		1840	callback. The optional C<data> argument will be stored in the watcher's
		1841	C<data> member and is free for you to use.
		1842
		1843	See the method-C<set> above for more details.
1682		1844
1683	=item w->set (struct ev_loop *)	1845	=item w->set (struct ev_loop *)
1684		1846
1685	Associates a different C<struct ev_loop> with this watcher. You can only	1847	Associates a different C<struct ev_loop> with this watcher. You can only
1686	do this when the watcher is inactive (and not pending either).	1848	do this when the watcher is inactive (and not pending either).
1687		1849
1688	=item w->set ([args])	1850	=item w->set ([args])
1689		1851
1690	Basically the same as C<ev_TYPE_set>, with the same args. Must be	1852	Basically the same as C<ev_TYPE_set>, with the same args. Must be
1691	called at least once. Unlike the C counterpart, an active watcher gets	1853	called at least once. Unlike the C counterpart, an active watcher gets
1692	automatically stopped and restarted.	1854	automatically stopped and restarted when reconfiguring it with this
		1855	method.
1693		1856
1694	=item w->start ()	1857	=item w->start ()
1695		1858
1696	Starts the watcher. Note that there is no C<loop> argument as the	1859	Starts the watcher. Note that there is no C<loop> argument, as the
1697	constructor already takes the loop.	1860	constructor already stores the event loop.
1698		1861
1699	=item w->stop ()	1862	=item w->stop ()
1700		1863
1701	Stops the watcher if it is active. Again, no C<loop> argument.	1864	Stops the watcher if it is active. Again, no C<loop> argument.
1702		1865
…		…
1727		1890
1728	myclass ();	1891	myclass ();
1729	}	1892	}
1730		1893
1731	myclass::myclass (int fd)	1894	myclass::myclass (int fd)
1732	: io (this, &myclass::io_cb),
1733	idle (this, &myclass::idle_cb)
1734	{	1895	{
		1896	io .set <myclass, &myclass::io_cb > (this);
		1897	idle.set <myclass, &myclass::idle_cb> (this);
		1898
1735	io.start (fd, ev::READ);	1899	io.start (fd, ev::READ);
1736	}	1900	}
1737		1901
1738		1902
1739	=head1 MACRO MAGIC	1903	=head1 MACRO MAGIC
1740		1904
1741	Libev can be compiled with a variety of options, the most fundemantal is	1905	Libev can be compiled with a variety of options, the most fundemantal is
1742	C<EV_MULTIPLICITY>. This option determines wether (most) functions and	1906	C<EV_MULTIPLICITY>. This option determines whether (most) functions and
1743	callbacks have an initial C<struct ev_loop *> argument.	1907	callbacks have an initial C<struct ev_loop *> argument.
1744		1908
1745	To make it easier to write programs that cope with either variant, the	1909	To make it easier to write programs that cope with either variant, the
1746	following macros are defined:	1910	following macros are defined:
1747		1911
…		…
1780	Similar to the other two macros, this gives you the value of the default	1944	Similar to the other two macros, this gives you the value of the default
1781	loop, if multiple loops are supported ("ev loop default").	1945	loop, if multiple loops are supported ("ev loop default").
1782		1946
1783	=back	1947	=back
1784		1948
1785	Example: Declare and initialise a check watcher, working regardless of	1949	Example: Declare and initialise a check watcher, utilising the above
1786	wether multiple loops are supported or not.	1950	macros so it will work regardless of whether multiple loops are supported
		1951	or not.
1787		1952
1788	static void	1953	static void
1789	check_cb (EV_P_ ev_timer *w, int revents)	1954	check_cb (EV_P_ ev_timer *w, int revents)
1790	{	1955	{
1791	ev_check_stop (EV_A_ w);	1956	ev_check_stop (EV_A_ w);
…		…
1793		1958
1794	ev_check check;	1959	ev_check check;
1795	ev_check_init (&check, check_cb);	1960	ev_check_init (&check, check_cb);
1796	ev_check_start (EV_DEFAULT_ &check);	1961	ev_check_start (EV_DEFAULT_ &check);
1797	ev_loop (EV_DEFAULT_ 0);	1962	ev_loop (EV_DEFAULT_ 0);
1798
1799		1963
1800	=head1 EMBEDDING	1964	=head1 EMBEDDING
1801		1965
1802	Libev can (and often is) directly embedded into host	1966	Libev can (and often is) directly embedded into host
1803	applications. Examples of applications that embed it include the Deliantra	1967	applications. Examples of applications that embed it include the Deliantra
…		…
1843	ev_vars.h	2007	ev_vars.h
1844	ev_wrap.h	2008	ev_wrap.h
1845		2009
1846	ev_win32.c required on win32 platforms only	2010	ev_win32.c required on win32 platforms only
1847		2011
1848	ev_select.c only when select backend is enabled (which is by default)	2012	ev_select.c only when select backend is enabled (which is enabled by default)
1849	ev_poll.c only when poll backend is enabled (disabled by default)	2013	ev_poll.c only when poll backend is enabled (disabled by default)
1850	ev_epoll.c only when the epoll backend is enabled (disabled by default)	2014	ev_epoll.c only when the epoll backend is enabled (disabled by default)
1851	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	2015	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1852	ev_port.c only when the solaris port backend is enabled (disabled by default)	2016	ev_port.c only when the solaris port backend is enabled (disabled by default)
1853		2017
…		…
1978		2142
1979	=item EV_USE_DEVPOLL	2143	=item EV_USE_DEVPOLL
1980		2144
1981	reserved for future expansion, works like the USE symbols above.	2145	reserved for future expansion, works like the USE symbols above.
1982		2146
		2147	=item EV_USE_INOTIFY
		2148
		2149	If defined to be C<1>, libev will compile in support for the Linux inotify
		2150	interface to speed up C<ev_stat> watchers. Its actual availability will
		2151	be detected at runtime.
		2152
1983	=item EV_H	2153	=item EV_H
1984		2154
1985	The name of the F<ev.h> header file used to include it. The default if	2155	The name of the F<ev.h> header file used to include it. The default if
1986	undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This	2156	undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This
1987	can be used to virtually rename the F<ev.h> header file in case of conflicts.	2157	can be used to virtually rename the F<ev.h> header file in case of conflicts.
…		…
2010	will have the C<struct ev_loop *> as first argument, and you can create	2180	will have the C<struct ev_loop *> as first argument, and you can create
2011	additional independent event loops. Otherwise there will be no support	2181	additional independent event loops. Otherwise there will be no support
2012	for multiple event loops and there is no first event loop pointer	2182	for multiple event loops and there is no first event loop pointer
2013	argument. Instead, all functions act on the single default loop.	2183	argument. Instead, all functions act on the single default loop.
2014		2184
		2185	=item EV_MINPRI
		2186
		2187	=item EV_MAXPRI
		2188
		2189	The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
		2190	C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
		2191	provide for more priorities by overriding those symbols (usually defined
		2192	to be C<-2> and C<2>, respectively).
		2193
		2194	When doing priority-based operations, libev usually has to linearly search
		2195	all the priorities, so having many of them (hundreds) uses a lot of space
		2196	and time, so using the defaults of five priorities (-2 .. +2) is usually
		2197	fine.
		2198
		2199	If your embedding app does not need any priorities, defining these both to
		2200	C<0> will save some memory and cpu.
		2201
2015	=item EV_PERIODIC_ENABLE	2202	=item EV_PERIODIC_ENABLE
2016		2203
2017	If undefined or defined to be C<1>, then periodic timers are supported. If	2204	If undefined or defined to be C<1>, then periodic timers are supported. If
2018	defined to be C<0>, then they are not. Disabling them saves a few kB of	2205	defined to be C<0>, then they are not. Disabling them saves a few kB of
2019	code.	2206	code.
2020		2207
		2208	=item EV_IDLE_ENABLE
		2209
		2210	If undefined or defined to be C<1>, then idle watchers are supported. If
		2211	defined to be C<0>, then they are not. Disabling them saves a few kB of
		2212	code.
		2213
2021	=item EV_EMBED_ENABLE	2214	=item EV_EMBED_ENABLE
2022		2215
2023	If undefined or defined to be C<1>, then embed watchers are supported. If	2216	If undefined or defined to be C<1>, then embed watchers are supported. If
2024	defined to be C<0>, then they are not.	2217	defined to be C<0>, then they are not.
2025		2218
…		…
2042	=item EV_PID_HASHSIZE	2235	=item EV_PID_HASHSIZE
2043		2236
2044	C<ev_child> watchers use a small hash table to distribute workload by	2237	C<ev_child> watchers use a small hash table to distribute workload by
2045	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more	2238	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more
2046	than enough. If you need to manage thousands of children you might want to	2239	than enough. If you need to manage thousands of children you might want to
2047	increase this value.	2240	increase this value (I<must> be a power of two).
		2241
		2242	=item EV_INOTIFY_HASHSIZE
		2243
		2244	C<ev_staz> watchers use a small hash table to distribute workload by
		2245	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),
		2246	usually more than enough. If you need to manage thousands of C<ev_stat>
		2247	watchers you might want to increase this value (I<must> be a power of
		2248	two).
2048		2249
2049	=item EV_COMMON	2250	=item EV_COMMON
2050		2251
2051	By default, all watchers have a C<void *data> member. By redefining	2252	By default, all watchers have a C<void *data> member. By redefining
2052	this macro to a something else you can include more and other types of	2253	this macro to a something else you can include more and other types of
…		…
2081	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file	2282	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file
2082	will be compiled. It is pretty complex because it provides its own header	2283	will be compiled. It is pretty complex because it provides its own header
2083	file.	2284	file.
2084		2285
2085	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	2286	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
2086	that everybody includes and which overrides some autoconf choices:	2287	that everybody includes and which overrides some configure choices:
2087		2288
		2289	#define EV_MINIMAL 1
2088	#define EV_USE_POLL 0	2290	#define EV_USE_POLL 0
2089	#define EV_MULTIPLICITY 0	2291	#define EV_MULTIPLICITY 0
2090	#define EV_PERIODICS 0	2292	#define EV_PERIODIC_ENABLE 0
		2293	#define EV_STAT_ENABLE 0
		2294	#define EV_FORK_ENABLE 0
2091	#define EV_CONFIG_H <config.h>	2295	#define EV_CONFIG_H <config.h>
		2296	#define EV_MINPRI 0
		2297	#define EV_MAXPRI 0
2092		2298
2093	#include "ev++.h"	2299	#include "ev++.h"
2094		2300
2095	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	2301	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
2096		2302
…		…
2102		2308
2103	In this section the complexities of (many of) the algorithms used inside	2309	In this section the complexities of (many of) the algorithms used inside
2104	libev will be explained. For complexity discussions about backends see the	2310	libev will be explained. For complexity discussions about backends see the
2105	documentation for C<ev_default_init>.	2311	documentation for C<ev_default_init>.
2106		2312
		2313	All of the following are about amortised time: If an array needs to be
		2314	extended, libev needs to realloc and move the whole array, but this
		2315	happens asymptotically never with higher number of elements, so O(1) might
		2316	mean it might do a lengthy realloc operation in rare cases, but on average
		2317	it is much faster and asymptotically approaches constant time.
		2318
2107	=over 4	2319	=over 4
2108		2320
2109	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	2321	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
2110		2322
		2323	This means that, when you have a watcher that triggers in one hour and
		2324	there are 100 watchers that would trigger before that then inserting will
		2325	have to skip those 100 watchers.
		2326
2111	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)	2327	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)
2112		2328
		2329	That means that for changing a timer costs less than removing/adding them
		2330	as only the relative motion in the event queue has to be paid for.
		2331
2113	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2332	=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2114		2333
		2334	These just add the watcher into an array or at the head of a list.
2115	=item Stopping check/prepare/idle watchers: O(1)	2335	=item Stopping check/prepare/idle watchers: O(1)
2116		2336
2117	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))	2337	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
		2338
		2339	These watchers are stored in lists then need to be walked to find the
		2340	correct watcher to remove. The lists are usually short (you don't usually
		2341	have many watchers waiting for the same fd or signal).
2118		2342
2119	=item Finding the next timer per loop iteration: O(1)	2343	=item Finding the next timer per loop iteration: O(1)
2120		2344
2121	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	2345	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2122		2346
		2347	A change means an I/O watcher gets started or stopped, which requires
		2348	libev to recalculate its status (and possibly tell the kernel).
		2349
2123	=item Activating one watcher: O(1)	2350	=item Activating one watcher: O(1)
2124		2351
		2352	=item Priority handling: O(number_of_priorities)
		2353
		2354	Priorities are implemented by allocating some space for each
		2355	priority. When doing priority-based operations, libev usually has to
		2356	linearly search all the priorities.
		2357
2125	=back	2358	=back
2126		2359
2127		2360
2128	=head1 AUTHOR	2361	=head1 AUTHOR
2129		2362

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Comparing libev/ev.pod (file contents): Revision 1.53 by root, Tue Nov 27 20:15:02 2007 UTC vs. Revision 1.73 by root, Sat Dec 8 03:53:36 2007 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.53 by root, Tue Nov 27 20:15:02 2007 UTC vs.
Revision 1.73 by root, Sat Dec 8 03:53:36 2007 UTC