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

Comparing libev/ev.pod (file contents):
Revision 1.46 by root, Mon Nov 26 10:20:43 2007 UTC vs.
Revision 1.69 by root, Fri Dec 7 19:15:39 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
48	the beginning of 1970, details are complicated, don't ask). This type is	100	the beginning of 1970, details are complicated, don't ask). This type is
49	called C<ev_tstamp>, which is what you should use too. It usually aliases	101	called C<ev_tstamp>, which is what you should use too. It usually aliases
50	to the C<double> type in C, and when you need to do any calculations on	102	to the C<double> type in C, and when you need to do any calculations on
51	it, you should treat it as such.	103	it, you should treat it as such.
52		104
53
54	=head1 GLOBAL FUNCTIONS	105	=head1 GLOBAL FUNCTIONS
55		106
56	These functions can be called anytime, even before initialising the	107	These functions can be called anytime, even before initialising the
57	library in any way.	108	library in any way.
58		109
…		…
77	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,
78	as this indicates an incompatible change. Minor versions are usually	129	as this indicates an incompatible change. Minor versions are usually
79	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
80	not a problem.	131	not a problem.
81		132
82	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
83	version:	134	version.
84		135
85	assert (("libev version mismatch",	136	assert (("libev version mismatch",
86	ev_version_major () == EV_VERSION_MAJOR	137	ev_version_major () == EV_VERSION_MAJOR
87	&& ev_version_minor () >= EV_VERSION_MINOR));	138	&& ev_version_minor () >= EV_VERSION_MINOR));
88		139
…		…
118		169
119	See the description of C<ev_embed> watchers for more info.	170	See the description of C<ev_embed> watchers for more info.
120		171
121	=item ev_set_allocator (void (cb)(void *ptr, long size))	172	=item ev_set_allocator (void (cb)(void *ptr, long size))
122		173
123	Sets the allocation function to use (the prototype is similar to the	174	Sets the allocation function to use (the prototype is similar - the
124	realloc C function, the semantics are identical). It is used to allocate	175	semantics is identical - to the realloc C function). It is used to
125	and free memory (no surprises here). If it returns zero when memory	176	allocate and free memory (no surprises here). If it returns zero when
126	needs to be allocated, the library might abort or take some potentially	177	memory needs to be allocated, the library might abort or take some
127	destructive action. The default is your system realloc function.	178	potentially destructive action. The default is your system realloc
		179	function.
128		180
129	You could override this function in high-availability programs to, say,	181	You could override this function in high-availability programs to, say,
130	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,
131	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.
132		184
133	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
134	retries: better than mine).	186	retries).
135		187
136	static void *	188	static void *
137	persistent_realloc (void *ptr, long size)	189	persistent_realloc (void *ptr, size_t size)
138	{	190	{
139	for (;;)	191	for (;;)
140	{	192	{
141	void *newptr = realloc (ptr, size);	193	void *newptr = realloc (ptr, size);
142		194
…		…
158	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
159	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
160	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
161	(such as abort).	213	(such as abort).
162		214
163	Example: do the same thing as libev does internally:	215	Example: This is basically the same thing that libev does internally, too.
164		216
165	static void	217	static void
166	fatal_error (const char *msg)	218	fatal_error (const char *msg)
167	{	219	{
168	perror (msg);	220	perror (msg);
…		…
218	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will	270	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
219	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
220	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
221	around bugs.	273	around bugs.
222		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
223	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	295	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
224		296
225	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
226	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,
227	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
…		…
314	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
315	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
316	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
317	undefined behaviour (or a failed assertion if assertions are enabled).	389	undefined behaviour (or a failed assertion if assertions are enabled).
318		390
319	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.
320		392
321	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	393	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
322	if (!epoller)	394	if (!epoller)
323	fatal ("no epoll found here, maybe it hides under your chair");	395	fatal ("no epoll found here, maybe it hides under your chair");
324		396
…		…
361	=item ev_loop_fork (loop)	433	=item ev_loop_fork (loop)
362		434
363	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
364	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
365	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.
366		448
367	=item unsigned int ev_backend (loop)	449	=item unsigned int ev_backend (loop)
368		450
369	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
370	use.	452	use.
…		…
423	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
424	be handled here by queueing them when their watcher gets executed.	506	be handled here by queueing them when their watcher gets executed.
425	- 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
426	were used, return, otherwise continue with step *.	508	were used, return, otherwise continue with step *.
427		509
428	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
429	anymore.	511	anymore.
430		512
431	... queue jobs here, make sure they register event watchers as long	513	... queue jobs here, make sure they register event watchers as long
432	... 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..)
433	ev_loop (my_loop, 0);	515	ev_loop (my_loop, 0);
…		…
453	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
454	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
455	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
456	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>.
457		539
458	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>
459	running when nothing else is active.	541	running when nothing else is active.
460		542
461	struct dv_signal exitsig;	543	struct ev_signal exitsig;
462	ev_signal_init (&exitsig, sig_cb, SIGINT);	544	ev_signal_init (&exitsig, sig_cb, SIGINT);
463	ev_signal_start (myloop, &exitsig);	545	ev_signal_start (loop, &exitsig);
464	evf_unref (myloop);	546	evf_unref (loop);
465		547
466	Example: for some weird reason, unregister the above signal handler again.	548	Example: For some weird reason, unregister the above signal handler again.
467		549
468	ev_ref (myloop);	550	ev_ref (loop);
469	ev_signal_stop (myloop, &exitsig);	551	ev_signal_stop (loop, &exitsig);
470		552
471	=back	553	=back
472		554
473		555
474	=head1 ANATOMY OF A WATCHER	556	=head1 ANATOMY OF A WATCHER
…		…
544	The signal specified in the C<ev_signal> watcher has been received by a thread.	626	The signal specified in the C<ev_signal> watcher has been received by a thread.
545		627
546	=item C<EV_CHILD>	628	=item C<EV_CHILD>
547		629
548	The pid specified in the C<ev_child> watcher has received a status change.	630	The pid specified in the C<ev_child> watcher has received a status change.
		631
		632	=item C<EV_STAT>
		633
		634	The path specified in the C<ev_stat> watcher changed its attributes somehow.
549		635
550	=item C<EV_IDLE>	636	=item C<EV_IDLE>
551		637
552	The C<ev_idle> watcher has determined that you have nothing better to do.	638	The C<ev_idle> watcher has determined that you have nothing better to do.
553		639
…		…
561	received events. Callbacks of both watcher types can start and stop as	647	received events. Callbacks of both watcher types can start and stop as
562	many watchers as they want, and all of them will be taken into account	648	many watchers as they want, and all of them will be taken into account
563	(for example, a C<ev_prepare> watcher might start an idle watcher to keep	649	(for example, a C<ev_prepare> watcher might start an idle watcher to keep
564	C<ev_loop> from blocking).	650	C<ev_loop> from blocking).
565		651
		652	=item C<EV_EMBED>
		653
		654	The embedded event loop specified in the C<ev_embed> watcher needs attention.
		655
		656	=item C<EV_FORK>
		657
		658	The event loop has been resumed in the child process after fork (see
		659	C<ev_fork>).
		660
566	=item C<EV_ERROR>	661	=item C<EV_ERROR>
567		662
568	An unspecified error has occured, the watcher has been stopped. This might	663	An unspecified error has occured, the watcher has been stopped. This might
569	happen because the watcher could not be properly started because libev	664	happen because the watcher could not be properly started because libev
570	ran out of memory, a file descriptor was found to be closed or any other	665	ran out of memory, a file descriptor was found to be closed or any other
…		…
644	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
645	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
646	C<ev_TYPE_set> is safe) and you must make sure the watcher is available to	741	C<ev_TYPE_set> is safe) and you must make sure the watcher is available to
647	libev (e.g. you cnanot C<free ()> it).	742	libev (e.g. you cnanot C<free ()> it).
648		743
649	=item callback = ev_cb (ev_TYPE *watcher)	744	=item callback ev_cb (ev_TYPE *watcher)
650		745
651	Returns the callback currently set on the watcher.	746	Returns the callback currently set on the watcher.
652		747
653	=item ev_cb_set (ev_TYPE *watcher, callback)	748	=item ev_cb_set (ev_TYPE *watcher, callback)
654		749
655	Change the callback. You can change the callback at virtually any time	750	Change the callback. You can change the callback at virtually any time
656	(modulo threads).	751	(modulo threads).
		752
		753	=item ev_set_priority (ev_TYPE *watcher, priority)
		754
		755	=item int ev_priority (ev_TYPE *watcher)
		756
		757	Set and query the priority of the watcher. The priority is a small
		758	integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
		759	(default: C<-2>). Pending watchers with higher priority will be invoked
		760	before watchers with lower priority, but priority will not keep watchers
		761	from being executed (except for C<ev_idle> watchers).
		762
		763	This means that priorities are I<only> used for ordering callback
		764	invocation after new events have been received. This is useful, for
		765	example, to reduce latency after idling, or more often, to bind two
		766	watchers on the same event and make sure one is called first.
		767
		768	If you need to suppress invocation when higher priority events are pending
		769	you need to look at C<ev_idle> watchers, which provide this functionality.
		770
		771	The default priority used by watchers when no priority has been set is
		772	always C<0>, which is supposed to not be too high and not be too low :).
		773
		774	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
		775	fine, as long as you do not mind that the priority value you query might
		776	or might not have been adjusted to be within valid range.
657		777
658	=back	778	=back
659		779
660		780
661	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER	781	=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
…		…
682	{	802	{
683	struct my_io w = (struct my_io )w_;	803	struct my_io w = (struct my_io )w_;
684	...	804	...
685	}	805	}
686		806
687	More interesting and less C-conformant ways of catsing your callback type	807	More interesting and less C-conformant ways of casting your callback type
688	have been omitted....	808	instead have been omitted.
		809
		810	Another common scenario is having some data structure with multiple
		811	watchers:
		812
		813	struct my_biggy
		814	{
		815	int some_data;
		816	ev_timer t1;
		817	ev_timer t2;
		818	}
		819
		820	In this case getting the pointer to C<my_biggy> is a bit more complicated,
		821	you need to use C<offsetof>:
		822
		823	#include <stddef.h>
		824
		825	static void
		826	t1_cb (EV_P_ struct ev_timer *w, int revents)
		827	{
		828	struct my_biggy big = (struct my_biggy *
		829	(((char *)w) - offsetof (struct my_biggy, t1));
		830	}
		831
		832	static void
		833	t2_cb (EV_P_ struct ev_timer *w, int revents)
		834	{
		835	struct my_biggy big = (struct my_biggy *
		836	(((char *)w) - offsetof (struct my_biggy, t2));
		837	}
689		838
690		839
691	=head1 WATCHER TYPES	840	=head1 WATCHER TYPES
692		841
693	This section describes each watcher in detail, but will not repeat	842	This section describes each watcher in detail, but will not repeat
694	information given in the last section.	843	information given in the last section. Any initialisation/set macros,
		844	functions and members specific to the watcher type are explained.
		845
		846	Members are additionally marked with either I<[read-only]>, meaning that,
		847	while the watcher is active, you can look at the member and expect some
		848	sensible content, but you must not modify it (you can modify it while the
		849	watcher is stopped to your hearts content), or I<[read-write]>, which
		850	means you can expect it to have some sensible content while the watcher
		851	is active, but you can also modify it. Modifying it may not do something
		852	sensible or take immediate effect (or do anything at all), but libev will
		853	not crash or malfunction in any way.
695		854
696		855
697	=head2 C<ev_io> - is this file descriptor readable or writable?	856	=head2 C<ev_io> - is this file descriptor readable or writable?
698		857
699	I/O watchers check whether a file descriptor is readable or writable	858	I/O watchers check whether a file descriptor is readable or writable
…		…
728	it is best to always use non-blocking I/O: An extra C<read>(2) returning	887	it is best to always use non-blocking I/O: An extra C<read>(2) returning
729	C<EAGAIN> is far preferable to a program hanging until some data arrives.	888	C<EAGAIN> is far preferable to a program hanging until some data arrives.
730		889
731	If you cannot run the fd in non-blocking mode (for example you should not	890	If you cannot run the fd in non-blocking mode (for example you should not
732	play around with an Xlib connection), then you have to seperately re-test	891	play around with an Xlib connection), then you have to seperately re-test
733	wether a file descriptor is really ready with a known-to-be good interface	892	whether a file descriptor is really ready with a known-to-be good interface
734	such as poll (fortunately in our Xlib example, Xlib already does this on	893	such as poll (fortunately in our Xlib example, Xlib already does this on
735	its own, so its quite safe to use).	894	its own, so its quite safe to use).
736		895
737	=over 4	896	=over 4
738		897
…		…
742		901
743	Configures an C<ev_io> watcher. The C<fd> is the file descriptor to	902	Configures an C<ev_io> watcher. The C<fd> is the file descriptor to
744	rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or	903	rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or
745	C<EV_READ \| EV_WRITE> to receive the given events.	904	C<EV_READ \| EV_WRITE> to receive the given events.
746		905
		906	=item int fd [read-only]
		907
		908	The file descriptor being watched.
		909
		910	=item int events [read-only]
		911
		912	The events being watched.
		913
747	=back	914	=back
748		915
749	Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well	916	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
750	readable, but only once. Since it is likely line-buffered, you could	917	readable, but only once. Since it is likely line-buffered, you could
751	attempt to read a whole line in the callback:	918	attempt to read a whole line in the callback.
752		919
753	static void	920	static void
754	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	921	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
755	{	922	{
756	ev_io_stop (loop, w);	923	ev_io_stop (loop, w);
…		…
808	=item ev_timer_again (loop)	975	=item ev_timer_again (loop)
809		976
810	This will act as if the timer timed out and restart it again if it is	977	This will act as if the timer timed out and restart it again if it is
811	repeating. The exact semantics are:	978	repeating. The exact semantics are:
812		979
		980	If the timer is pending, its pending status is cleared.
		981
813	If the timer is started but nonrepeating, stop it.	982	If the timer is started but nonrepeating, stop it (as if it timed out).
814		983
815	If the timer is repeating, either start it if necessary (with the repeat	984	If the timer is repeating, either start it if necessary (with the
816	value), or reset the running timer to the repeat value.	985	C<repeat> value), or reset the running timer to the C<repeat> value.
817		986
818	This sounds a bit complicated, but here is a useful and typical	987	This sounds a bit complicated, but here is a useful and typical
819	example: Imagine you have a tcp connection and you want a so-called idle	988	example: Imagine you have a tcp connection and you want a so-called idle
820	timeout, that is, you want to be called when there have been, say, 60	989	timeout, that is, you want to be called when there have been, say, 60
821	seconds of inactivity on the socket. The easiest way to do this is to	990	seconds of inactivity on the socket. The easiest way to do this is to
822	configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each	991	configure an C<ev_timer> with a C<repeat> value of C<60> and then call
823	time you successfully read or write some data. If you go into an idle	992	C<ev_timer_again> each time you successfully read or write some data. If
824	state where you do not expect data to travel on the socket, you can stop	993	you go into an idle state where you do not expect data to travel on the
825	the timer, and again will automatically restart it if need be.	994	socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will
		995	automatically restart it if need be.
		996
		997	That means you can ignore the C<after> value and C<ev_timer_start>
		998	altogether and only ever use the C<repeat> value and C<ev_timer_again>:
		999
		1000	ev_timer_init (timer, callback, 0., 5.);
		1001	ev_timer_again (loop, timer);
		1002	...
		1003	timer->again = 17.;
		1004	ev_timer_again (loop, timer);
		1005	...
		1006	timer->again = 10.;
		1007	ev_timer_again (loop, timer);
		1008
		1009	This is more slightly efficient then stopping/starting the timer each time
		1010	you want to modify its timeout value.
		1011
		1012	=item ev_tstamp repeat [read-write]
		1013
		1014	The current C<repeat> value. Will be used each time the watcher times out
		1015	or C<ev_timer_again> is called and determines the next timeout (if any),
		1016	which is also when any modifications are taken into account.
826		1017
827	=back	1018	=back
828		1019
829	Example: create a timer that fires after 60 seconds.	1020	Example: Create a timer that fires after 60 seconds.
830		1021
831	static void	1022	static void
832	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1023	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
833	{	1024	{
834	.. one minute over, w is actually stopped right here	1025	.. one minute over, w is actually stopped right here
…		…
836		1027
837	struct ev_timer mytimer;	1028	struct ev_timer mytimer;
838	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1029	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
839	ev_timer_start (loop, &mytimer);	1030	ev_timer_start (loop, &mytimer);
840		1031
841	Example: create a timeout timer that times out after 10 seconds of	1032	Example: Create a timeout timer that times out after 10 seconds of
842	inactivity.	1033	inactivity.
843		1034
844	static void	1035	static void
845	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1036	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
846	{	1037	{
…		…
957	Simply stops and restarts the periodic watcher again. This is only useful	1148	Simply stops and restarts the periodic watcher again. This is only useful
958	when you changed some parameters or the reschedule callback would return	1149	when you changed some parameters or the reschedule callback would return
959	a different time than the last time it was called (e.g. in a crond like	1150	a different time than the last time it was called (e.g. in a crond like
960	program when the crontabs have changed).	1151	program when the crontabs have changed).
961		1152
		1153	=item ev_tstamp interval [read-write]
		1154
		1155	The current interval value. Can be modified any time, but changes only
		1156	take effect when the periodic timer fires or C<ev_periodic_again> is being
		1157	called.
		1158
		1159	=item ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]
		1160
		1161	The current reschedule callback, or C<0>, if this functionality is
		1162	switched off. Can be changed any time, but changes only take effect when
		1163	the periodic timer fires or C<ev_periodic_again> is being called.
		1164
962	=back	1165	=back
963		1166
964	Example: call a callback every hour, or, more precisely, whenever the	1167	Example: Call a callback every hour, or, more precisely, whenever the
965	system clock is divisible by 3600. The callback invocation times have	1168	system clock is divisible by 3600. The callback invocation times have
966	potentially a lot of jittering, but good long-term stability.	1169	potentially a lot of jittering, but good long-term stability.
967		1170
968	static void	1171	static void
969	clock_cb (struct ev_loop loop, struct ev_io w, int revents)	1172	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
…		…
973		1176
974	struct ev_periodic hourly_tick;	1177	struct ev_periodic hourly_tick;
975	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1178	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
976	ev_periodic_start (loop, &hourly_tick);	1179	ev_periodic_start (loop, &hourly_tick);
977		1180
978	Example: the same as above, but use a reschedule callback to do it:	1181	Example: The same as above, but use a reschedule callback to do it:
979		1182
980	#include <math.h>	1183	#include <math.h>
981		1184
982	static ev_tstamp	1185	static ev_tstamp
983	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1186	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
…		…
985	return fmod (now, 3600.) + 3600.;	1188	return fmod (now, 3600.) + 3600.;
986	}	1189	}
987		1190
988	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1191	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
989		1192
990	Example: call a callback every hour, starting now:	1193	Example: Call a callback every hour, starting now:
991		1194
992	struct ev_periodic hourly_tick;	1195	struct ev_periodic hourly_tick;
993	ev_periodic_init (&hourly_tick, clock_cb,	1196	ev_periodic_init (&hourly_tick, clock_cb,
994	fmod (ev_now (loop), 3600.), 3600., 0);	1197	fmod (ev_now (loop), 3600.), 3600., 0);
995	ev_periodic_start (loop, &hourly_tick);	1198	ev_periodic_start (loop, &hourly_tick);
…		…
1016	=item ev_signal_set (ev_signal *, int signum)	1219	=item ev_signal_set (ev_signal *, int signum)
1017		1220
1018	Configures the watcher to trigger on the given signal number (usually one	1221	Configures the watcher to trigger on the given signal number (usually one
1019	of the C<SIGxxx> constants).	1222	of the C<SIGxxx> constants).
1020		1223
		1224	=item int signum [read-only]
		1225
		1226	The signal the watcher watches out for.
		1227
1021	=back	1228	=back
1022		1229
1023		1230
1024	=head2 C<ev_child> - watch out for process status changes	1231	=head2 C<ev_child> - watch out for process status changes
1025		1232
…		…
1037	at the C<rstatus> member of the C<ev_child> watcher structure to see	1244	at the C<rstatus> member of the C<ev_child> watcher structure to see
1038	the status word (use the macros from C<sys/wait.h> and see your systems	1245	the status word (use the macros from C<sys/wait.h> and see your systems
1039	C<waitpid> documentation). The C<rpid> member contains the pid of the	1246	C<waitpid> documentation). The C<rpid> member contains the pid of the
1040	process causing the status change.	1247	process causing the status change.
1041		1248
		1249	=item int pid [read-only]
		1250
		1251	The process id this watcher watches out for, or C<0>, meaning any process id.
		1252
		1253	=item int rpid [read-write]
		1254
		1255	The process id that detected a status change.
		1256
		1257	=item int rstatus [read-write]
		1258
		1259	The process exit/trace status caused by C<rpid> (see your systems
		1260	C<waitpid> and C<sys/wait.h> documentation for details).
		1261
1042	=back	1262	=back
1043		1263
1044	Example: try to exit cleanly on SIGINT and SIGTERM.	1264	Example: Try to exit cleanly on SIGINT and SIGTERM.
1045		1265
1046	static void	1266	static void
1047	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1267	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1048	{	1268	{
1049	ev_unloop (loop, EVUNLOOP_ALL);	1269	ev_unloop (loop, EVUNLOOP_ALL);
…		…
1052	struct ev_signal signal_watcher;	1272	struct ev_signal signal_watcher;
1053	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1273	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1054	ev_signal_start (loop, &sigint_cb);	1274	ev_signal_start (loop, &sigint_cb);
1055		1275
1056		1276
		1277	=head2 C<ev_stat> - did the file attributes just change?
		1278
		1279	This watches a filesystem path for attribute changes. That is, it calls
		1280	C<stat> regularly (or when the OS says it changed) and sees if it changed
		1281	compared to the last time, invoking the callback if it did.
		1282
		1283	The path does not need to exist: changing from "path exists" to "path does
		1284	not exist" is a status change like any other. The condition "path does
		1285	not exist" is signified by the C<st_nlink> field being zero (which is
		1286	otherwise always forced to be at least one) and all the other fields of
		1287	the stat buffer having unspecified contents.
		1288
		1289	The path I<should> be absolute and I<must not> end in a slash. If it is
		1290	relative and your working directory changes, the behaviour is undefined.
		1291
		1292	Since there is no standard to do this, the portable implementation simply
		1293	calls C<stat (2)> regularly on the path to see if it changed somehow. You
		1294	can specify a recommended polling interval for this case. If you specify
		1295	a polling interval of C<0> (highly recommended!) then a I<suitable,
		1296	unspecified default> value will be used (which you can expect to be around
		1297	five seconds, although this might change dynamically). Libev will also
		1298	impose a minimum interval which is currently around C<0.1>, but thats
		1299	usually overkill.
		1300
		1301	This watcher type is not meant for massive numbers of stat watchers,
		1302	as even with OS-supported change notifications, this can be
		1303	resource-intensive.
		1304
		1305	At the time of this writing, only the Linux inotify interface is
		1306	implemented (implementing kqueue support is left as an exercise for the
		1307	reader). Inotify will be used to give hints only and should not change the
		1308	semantics of C<ev_stat> watchers, which means that libev sometimes needs
		1309	to fall back to regular polling again even with inotify, but changes are
		1310	usually detected immediately, and if the file exists there will be no
		1311	polling.
		1312
		1313	=over 4
		1314
		1315	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)
		1316
		1317	=item ev_stat_set (ev_stat , const char path, ev_tstamp interval)
		1318
		1319	Configures the watcher to wait for status changes of the given
		1320	C<path>. The C<interval> is a hint on how quickly a change is expected to
		1321	be detected and should normally be specified as C<0> to let libev choose
		1322	a suitable value. The memory pointed to by C<path> must point to the same
		1323	path for as long as the watcher is active.
		1324
		1325	The callback will be receive C<EV_STAT> when a change was detected,
		1326	relative to the attributes at the time the watcher was started (or the
		1327	last change was detected).
		1328
		1329	=item ev_stat_stat (ev_stat *)
		1330
		1331	Updates the stat buffer immediately with new values. If you change the
		1332	watched path in your callback, you could call this fucntion to avoid
		1333	detecting this change (while introducing a race condition). Can also be
		1334	useful simply to find out the new values.
		1335
		1336	=item ev_statdata attr [read-only]
		1337
		1338	The most-recently detected attributes of the file. Although the type is of
		1339	C<ev_statdata>, this is usually the (or one of the) C<struct stat> types
		1340	suitable for your system. If the C<st_nlink> member is C<0>, then there
		1341	was some error while C<stat>ing the file.
		1342
		1343	=item ev_statdata prev [read-only]
		1344
		1345	The previous attributes of the file. The callback gets invoked whenever
		1346	C<prev> != C<attr>.
		1347
		1348	=item ev_tstamp interval [read-only]
		1349
		1350	The specified interval.
		1351
		1352	=item const char *path [read-only]
		1353
		1354	The filesystem path that is being watched.
		1355
		1356	=back
		1357
		1358	Example: Watch C</etc/passwd> for attribute changes.
		1359
		1360	static void
		1361	passwd_cb (struct ev_loop loop, ev_stat w, int revents)
		1362	{
		1363	/* /etc/passwd changed in some way */
		1364	if (w->attr.st_nlink)
		1365	{
		1366	printf ("passwd current size %ld\n", (long)w->attr.st_size);
		1367	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
		1368	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
		1369	}
		1370	else
		1371	/* you shalt not abuse printf for puts */
		1372	puts ("wow, /etc/passwd is not there, expect problems. "
		1373	"if this is windows, they already arrived\n");
		1374	}
		1375
		1376	...
		1377	ev_stat passwd;
		1378
		1379	ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
		1380	ev_stat_start (loop, &passwd);
		1381
		1382
1057	=head2 C<ev_idle> - when you've got nothing better to do...	1383	=head2 C<ev_idle> - when you've got nothing better to do...
1058		1384
1059	Idle watchers trigger events when there are no other events are pending	1385	Idle watchers trigger events when no other events of the same or higher
1060	(prepare, check and other idle watchers do not count). That is, as long	1386	priority are pending (prepare, check and other idle watchers do not
1061	as your process is busy handling sockets or timeouts (or even signals,	1387	count).
1062	imagine) it will not be triggered. But when your process is idle all idle	1388
1063	watchers are being called again and again, once per event loop iteration -	1389	That is, as long as your process is busy handling sockets or timeouts
		1390	(or even signals, imagine) of the same or higher priority it will not be
		1391	triggered. But when your process is idle (or only lower-priority watchers
		1392	are pending), the idle watchers are being called once per event loop
1064	until stopped, that is, or your process receives more events and becomes	1393	iteration - until stopped, that is, or your process receives more events
1065	busy.	1394	and becomes busy again with higher priority stuff.
1066		1395
1067	The most noteworthy effect is that as long as any idle watchers are	1396	The most noteworthy effect is that as long as any idle watchers are
1068	active, the process will not block when waiting for new events.	1397	active, the process will not block when waiting for new events.
1069		1398
1070	Apart from keeping your process non-blocking (which is a useful	1399	Apart from keeping your process non-blocking (which is a useful
…		…
1080	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,	1409	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
1081	believe me.	1410	believe me.
1082		1411
1083	=back	1412	=back
1084		1413
1085	Example: dynamically allocate an C<ev_idle>, start it, and in the	1414	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1086	callback, free it. Alos, use no error checking, as usual.	1415	callback, free it. Also, use no error checking, as usual.
1087		1416
1088	static void	1417	static void
1089	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1418	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1090	{	1419	{
1091	free (w);	1420	free (w);
…		…
1170		1499
1171	// create io watchers for each fd and a timer before blocking	1500	// create io watchers for each fd and a timer before blocking
1172	static void	1501	static void
1173	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)	1502	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
1174	{	1503	{
1175	int timeout = 3600000;truct pollfd fds [nfd];	1504	int timeout = 3600000;
		1505	struct pollfd fds [nfd];
1176	// actual code will need to loop here and realloc etc.	1506	// actual code will need to loop here and realloc etc.
1177	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1507	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1178		1508
1179	/* the callback is illegal, but won't be called as we stop during check */	1509	/* the callback is illegal, but won't be called as we stop during check */
1180	ev_timer_init (&tw, 0, timeout * 1e-3);	1510	ev_timer_init (&tw, 0, timeout * 1e-3);
…		…
1292		1622
1293	Make a single, non-blocking sweep over the embedded loop. This works	1623	Make a single, non-blocking sweep over the embedded loop. This works
1294	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	1624	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
1295	apropriate way for embedded loops.	1625	apropriate way for embedded loops.
1296		1626
		1627	=item struct ev_loop *loop [read-only]
		1628
		1629	The embedded event loop.
		1630
		1631	=back
		1632
		1633
		1634	=head2 C<ev_fork> - the audacity to resume the event loop after a fork
		1635
		1636	Fork watchers are called when a C<fork ()> was detected (usually because
		1637	whoever is a good citizen cared to tell libev about it by calling
		1638	C<ev_default_fork> or C<ev_loop_fork>). The invocation is done before the
		1639	event loop blocks next and before C<ev_check> watchers are being called,
		1640	and only in the child after the fork. If whoever good citizen calling
		1641	C<ev_default_fork> cheats and calls it in the wrong process, the fork
		1642	handlers will be invoked, too, of course.
		1643
		1644	=over 4
		1645
		1646	=item ev_fork_init (ev_signal *, callback)
		1647
		1648	Initialises and configures the fork watcher - it has no parameters of any
		1649	kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
		1650	believe me.
		1651
1297	=back	1652	=back
1298		1653
1299		1654
1300	=head1 OTHER FUNCTIONS	1655	=head1 OTHER FUNCTIONS
1301		1656
…		…
1463		1818
1464	=item w->sweep () C<ev::embed> only	1819	=item w->sweep () C<ev::embed> only
1465		1820
1466	Invokes C<ev_embed_sweep>.	1821	Invokes C<ev_embed_sweep>.
1467		1822
		1823	=item w->update () C<ev::stat> only
		1824
		1825	Invokes C<ev_stat_stat>.
		1826
1468	=back	1827	=back
1469		1828
1470	=back	1829	=back
1471		1830
1472	Example: Define a class with an IO and idle watcher, start one of them in	1831	Example: Define a class with an IO and idle watcher, start one of them in
…		…
1485	idle (this, &myclass::idle_cb)	1844	idle (this, &myclass::idle_cb)
1486	{	1845	{
1487	io.start (fd, ev::READ);	1846	io.start (fd, ev::READ);
1488	}	1847	}
1489		1848
		1849
		1850	=head1 MACRO MAGIC
		1851
		1852	Libev can be compiled with a variety of options, the most fundemantal is
		1853	C<EV_MULTIPLICITY>. This option determines whether (most) functions and
		1854	callbacks have an initial C<struct ev_loop *> argument.
		1855
		1856	To make it easier to write programs that cope with either variant, the
		1857	following macros are defined:
		1858
		1859	=over 4
		1860
		1861	=item C<EV_A>, C<EV_A_>
		1862
		1863	This provides the loop I<argument> for functions, if one is required ("ev
		1864	loop argument"). The C<EV_A> form is used when this is the sole argument,
		1865	C<EV_A_> is used when other arguments are following. Example:
		1866
		1867	ev_unref (EV_A);
		1868	ev_timer_add (EV_A_ watcher);
		1869	ev_loop (EV_A_ 0);
		1870
		1871	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
		1872	which is often provided by the following macro.
		1873
		1874	=item C<EV_P>, C<EV_P_>
		1875
		1876	This provides the loop I<parameter> for functions, if one is required ("ev
		1877	loop parameter"). The C<EV_P> form is used when this is the sole parameter,
		1878	C<EV_P_> is used when other parameters are following. Example:
		1879
		1880	// this is how ev_unref is being declared
		1881	static void ev_unref (EV_P);
		1882
		1883	// this is how you can declare your typical callback
		1884	static void cb (EV_P_ ev_timer *w, int revents)
		1885
		1886	It declares a parameter C<loop> of type C<struct ev_loop *>, quite
		1887	suitable for use with C<EV_A>.
		1888
		1889	=item C<EV_DEFAULT>, C<EV_DEFAULT_>
		1890
		1891	Similar to the other two macros, this gives you the value of the default
		1892	loop, if multiple loops are supported ("ev loop default").
		1893
		1894	=back
		1895
		1896	Example: Declare and initialise a check watcher, utilising the above
		1897	macros so it will work regardless of whether multiple loops are supported
		1898	or not.
		1899
		1900	static void
		1901	check_cb (EV_P_ ev_timer *w, int revents)
		1902	{
		1903	ev_check_stop (EV_A_ w);
		1904	}
		1905
		1906	ev_check check;
		1907	ev_check_init (&check, check_cb);
		1908	ev_check_start (EV_DEFAULT_ &check);
		1909	ev_loop (EV_DEFAULT_ 0);
		1910
1490	=head1 EMBEDDING	1911	=head1 EMBEDDING
1491		1912
1492	Libev can (and often is) directly embedded into host	1913	Libev can (and often is) directly embedded into host
1493	applications. Examples of applications that embed it include the Deliantra	1914	applications. Examples of applications that embed it include the Deliantra
1494	Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)	1915	Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
…		…
1533	ev_vars.h	1954	ev_vars.h
1534	ev_wrap.h	1955	ev_wrap.h
1535		1956
1536	ev_win32.c required on win32 platforms only	1957	ev_win32.c required on win32 platforms only
1537		1958
1538	ev_select.c only when select backend is enabled (which is by default)	1959	ev_select.c only when select backend is enabled (which is enabled by default)
1539	ev_poll.c only when poll backend is enabled (disabled by default)	1960	ev_poll.c only when poll backend is enabled (disabled by default)
1540	ev_epoll.c only when the epoll backend is enabled (disabled by default)	1961	ev_epoll.c only when the epoll backend is enabled (disabled by default)
1541	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	1962	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1542	ev_port.c only when the solaris port backend is enabled (disabled by default)	1963	ev_port.c only when the solaris port backend is enabled (disabled by default)
1543		1964
…		…
1668		2089
1669	=item EV_USE_DEVPOLL	2090	=item EV_USE_DEVPOLL
1670		2091
1671	reserved for future expansion, works like the USE symbols above.	2092	reserved for future expansion, works like the USE symbols above.
1672		2093
		2094	=item EV_USE_INOTIFY
		2095
		2096	If defined to be C<1>, libev will compile in support for the Linux inotify
		2097	interface to speed up C<ev_stat> watchers. Its actual availability will
		2098	be detected at runtime.
		2099
1673	=item EV_H	2100	=item EV_H
1674		2101
1675	The name of the F<ev.h> header file used to include it. The default if	2102	The name of the F<ev.h> header file used to include it. The default if
1676	undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This	2103	undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This
1677	can be used to virtually rename the F<ev.h> header file in case of conflicts.	2104	can be used to virtually rename the F<ev.h> header file in case of conflicts.
…		…
1700	will have the C<struct ev_loop *> as first argument, and you can create	2127	will have the C<struct ev_loop *> as first argument, and you can create
1701	additional independent event loops. Otherwise there will be no support	2128	additional independent event loops. Otherwise there will be no support
1702	for multiple event loops and there is no first event loop pointer	2129	for multiple event loops and there is no first event loop pointer
1703	argument. Instead, all functions act on the single default loop.	2130	argument. Instead, all functions act on the single default loop.
1704		2131
		2132	=item EV_MINPRI
		2133
		2134	=item EV_MAXPRI
		2135
		2136	The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
		2137	C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
		2138	provide for more priorities by overriding those symbols (usually defined
		2139	to be C<-2> and C<2>, respectively).
		2140
		2141	When doing priority-based operations, libev usually has to linearly search
		2142	all the priorities, so having many of them (hundreds) uses a lot of space
		2143	and time, so using the defaults of five priorities (-2 .. +2) is usually
		2144	fine.
		2145
		2146	If your embedding app does not need any priorities, defining these both to
		2147	C<0> will save some memory and cpu.
		2148
1705	=item EV_PERIODICS	2149	=item EV_PERIODIC_ENABLE
1706		2150
1707	If undefined or defined to be C<1>, then periodic timers are supported,	2151	If undefined or defined to be C<1>, then periodic timers are supported. If
1708	otherwise not. This saves a few kb of code.	2152	defined to be C<0>, then they are not. Disabling them saves a few kB of
		2153	code.
		2154
		2155	=item EV_IDLE_ENABLE
		2156
		2157	If undefined or defined to be C<1>, then idle watchers are supported. If
		2158	defined to be C<0>, then they are not. Disabling them saves a few kB of
		2159	code.
		2160
		2161	=item EV_EMBED_ENABLE
		2162
		2163	If undefined or defined to be C<1>, then embed watchers are supported. If
		2164	defined to be C<0>, then they are not.
		2165
		2166	=item EV_STAT_ENABLE
		2167
		2168	If undefined or defined to be C<1>, then stat watchers are supported. If
		2169	defined to be C<0>, then they are not.
		2170
		2171	=item EV_FORK_ENABLE
		2172
		2173	If undefined or defined to be C<1>, then fork watchers are supported. If
		2174	defined to be C<0>, then they are not.
		2175
		2176	=item EV_MINIMAL
		2177
		2178	If you need to shave off some kilobytes of code at the expense of some
		2179	speed, define this symbol to C<1>. Currently only used for gcc to override
		2180	some inlining decisions, saves roughly 30% codesize of amd64.
		2181
		2182	=item EV_PID_HASHSIZE
		2183
		2184	C<ev_child> watchers use a small hash table to distribute workload by
		2185	pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more
		2186	than enough. If you need to manage thousands of children you might want to
		2187	increase this value (I<must> be a power of two).
		2188
		2189	=item EV_INOTIFY_HASHSIZE
		2190
		2191	C<ev_staz> watchers use a small hash table to distribute workload by
		2192	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),
		2193	usually more than enough. If you need to manage thousands of C<ev_stat>
		2194	watchers you might want to increase this value (I<must> be a power of
		2195	two).
1709		2196
1710	=item EV_COMMON	2197	=item EV_COMMON
1711		2198
1712	By default, all watchers have a C<void *data> member. By redefining	2199	By default, all watchers have a C<void *data> member. By redefining
1713	this macro to a something else you can include more and other types of	2200	this macro to a something else you can include more and other types of
…		…
1742	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file	2229	interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file
1743	will be compiled. It is pretty complex because it provides its own header	2230	will be compiled. It is pretty complex because it provides its own header
1744	file.	2231	file.
1745		2232
1746	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	2233	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
1747	that everybody includes and which overrides some autoconf choices:	2234	that everybody includes and which overrides some configure choices:
1748		2235
		2236	#define EV_MINIMAL 1
1749	#define EV_USE_POLL 0	2237	#define EV_USE_POLL 0
1750	#define EV_MULTIPLICITY 0	2238	#define EV_MULTIPLICITY 0
1751	#define EV_PERIODICS 0	2239	#define EV_PERIODIC_ENABLE 0
		2240	#define EV_STAT_ENABLE 0
		2241	#define EV_FORK_ENABLE 0
1752	#define EV_CONFIG_H <config.h>	2242	#define EV_CONFIG_H <config.h>
		2243	#define EV_MINPRI 0
		2244	#define EV_MAXPRI 0
1753		2245
1754	#include "ev++.h"	2246	#include "ev++.h"
1755		2247
1756	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	2248	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
1757		2249
…		…
1767		2259
1768	=over 4	2260	=over 4
1769		2261
1770	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	2262	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
1771		2263
		2264	This means that, when you have a watcher that triggers in one hour and
		2265	there are 100 watchers that would trigger before that then inserting will
		2266	have to skip those 100 watchers.
		2267
1772	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)	2268	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)
1773		2269
		2270	That means that for changing a timer costs less than removing/adding them
		2271	as only the relative motion in the event queue has to be paid for.
		2272
1774	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2273	=item Starting io/check/prepare/idle/signal/child watchers: O(1)
1775		2274
		2275	These just add the watcher into an array or at the head of a list. If
		2276	the array needs to be extended libev needs to realloc and move the whole
		2277	array, but this happen asymptotically less and less with more watchers,
		2278	thus amortised O(1).
		2279
1776	=item Stopping check/prepare/idle watchers: O(1)	2280	=item Stopping check/prepare/idle watchers: O(1)
1777		2281
1778	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))	2282	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
		2283
		2284	These watchers are stored in lists then need to be walked to find the
		2285	correct watcher to remove. The lists are usually short (you don't usually
		2286	have many watchers waiting for the same fd or signal).
1779		2287
1780	=item Finding the next timer per loop iteration: O(1)	2288	=item Finding the next timer per loop iteration: O(1)
1781		2289
1782	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	2290	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
1783		2291
		2292	A change means an I/O watcher gets started or stopped, which requires
		2293	libev to recalculate its status (and possibly tell the kernel).
		2294
1784	=item Activating one watcher: O(1)	2295	=item Activating one watcher: O(1)
1785		2296
		2297	=item Priority handling: O(number_of_priorities)
		2298
		2299	Priorities are implemented by allocating some space for each
		2300	priority. When doing priority-based operations, libev usually has to
		2301	linearly search all the priorities.
		2302
1786	=back	2303	=back
1787		2304
1788		2305
1789	=head1 AUTHOR	2306	=head1 AUTHOR
1790		2307

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Comparing libev/ev.pod (file contents): Revision 1.46 by root, Mon Nov 26 10:20:43 2007 UTC vs. Revision 1.69 by root, Fri Dec 7 19:15:39 2007 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.46 by root, Mon Nov 26 10:20:43 2007 UTC vs.
Revision 1.69 by root, Fri Dec 7 19:15:39 2007 UTC