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

Comparing libev/ev.pod (file contents):
Revision 1.198 by root, Thu Oct 23 06:30:48 2008 UTC vs.
Revision 1.220 by root, Thu Nov 20 11:25:15 2008 UTC

…		…
9	=head2 EXAMPLE PROGRAM	9	=head2 EXAMPLE PROGRAM
10		10
11	// a single header file is required	11	// a single header file is required
12	#include <ev.h>	12	#include <ev.h>
13		13
		14	#include <stdio.h> // for puts
		15
14	// every watcher type has its own typedef'd struct	16	// every watcher type has its own typedef'd struct
15	// with the name ev_<type>	17	// with the name ev_TYPE
16	ev_io stdin_watcher;	18	ev_io stdin_watcher;
17	ev_timer timeout_watcher;	19	ev_timer timeout_watcher;
18		20
19	// all watcher callbacks have a similar signature	21	// all watcher callbacks have a similar signature
20	// this callback is called when data is readable on stdin	22	// this callback is called when data is readable on stdin
…		…
41		43
42	int	44	int
43	main (void)	45	main (void)
44	{	46	{
45	// use the default event loop unless you have special needs	47	// use the default event loop unless you have special needs
46	ev_loop *loop = ev_default_loop (0);	48	struct ev_loop *loop = ev_default_loop (0);
47		49
48	// initialise an io watcher, then start it	50	// initialise an io watcher, then start it
49	// this one will watch for stdin to become readable	51	// this one will watch for stdin to become readable
50	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);	52	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
51	ev_io_start (loop, &stdin_watcher);	53	ev_io_start (loop, &stdin_watcher);
…		…
276		278
277	=back	279	=back
278		280
279	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP	281	=head1 FUNCTIONS CONTROLLING THE EVENT LOOP
280		282
281	An event loop is described by a C<ev_loop *>. The library knows two	283	An event loop is described by a C<struct ev_loop *> (the C<struct>
282	types of such loops, the I<default> loop, which supports signals and child	284	is I<not> optional in this case, as there is also an C<ev_loop>
283	events, and dynamically created loops which do not.	285	I<function>).
		286
		287	The library knows two types of such loops, the I<default> loop, which
		288	supports signals and child events, and dynamically created loops which do
		289	not.
284		290
285	=over 4	291	=over 4
286		292
287	=item struct ev_loop *ev_default_loop (unsigned int flags)	293	=item struct ev_loop *ev_default_loop (unsigned int flags)
288		294
…		…
294	If you don't know what event loop to use, use the one returned from this	300	If you don't know what event loop to use, use the one returned from this
295	function.	301	function.
296		302
297	Note that this function is I<not> thread-safe, so if you want to use it	303	Note that this function is I<not> thread-safe, so if you want to use it
298	from multiple threads, you have to lock (note also that this is unlikely,	304	from multiple threads, you have to lock (note also that this is unlikely,
299	as loops cannot bes hared easily between threads anyway).	305	as loops cannot be shared easily between threads anyway).
300		306
301	The default loop is the only loop that can handle C<ev_signal> and	307	The default loop is the only loop that can handle C<ev_signal> and
302	C<ev_child> watchers, and to do this, it always registers a handler	308	C<ev_child> watchers, and to do this, it always registers a handler
303	for C<SIGCHLD>. If this is a problem for your application you can either	309	for C<SIGCHLD>. If this is a problem for your application you can either
304	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you	310	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you
…		…
380	=item C<EVBACKEND_EPOLL> (value 4, Linux)	386	=item C<EVBACKEND_EPOLL> (value 4, Linux)
381		387
382	For few fds, this backend is a bit little slower than poll and select,	388	For few fds, this backend is a bit little slower than poll and select,
383	but it scales phenomenally better. While poll and select usually scale	389	but it scales phenomenally better. While poll and select usually scale
384	like O(total_fds) where n is the total number of fds (or the highest fd),	390	like O(total_fds) where n is the total number of fds (or the highest fd),
385	epoll scales either O(1) or O(active_fds). The epoll design has a number	391	epoll scales either O(1) or O(active_fds).
386	of shortcomings, such as silently dropping events in some hard-to-detect	392
387	cases and requiring a system call per fd change, no fork support and bad	393	The epoll mechanism deserves honorable mention as the most misdesigned
388	support for dup.	394	of the more advanced event mechanisms: mere annoyances include silently
		395	dropping file descriptors, requiring a system call per change per file
		396	descriptor (and unnecessary guessing of parameters), problems with dup and
		397	so on. The biggest issue is fork races, however - if a program forks then
		398	I<both> parent and child process have to recreate the epoll set, which can
		399	take considerable time (one syscall per file descriptor) and is of course
		400	hard to detect.
		401
		402	Epoll is also notoriously buggy - embedding epoll fds I<should> work, but
		403	of course I<doesn't>, and epoll just loves to report events for totally
		404	I<different> file descriptors (even already closed ones, so one cannot
		405	even remove them from the set) than registered in the set (especially
		406	on SMP systems). Libev tries to counter these spurious notifications by
		407	employing an additional generation counter and comparing that against the
		408	events to filter out spurious ones, recreating the set when required.
389		409
390	While stopping, setting and starting an I/O watcher in the same iteration	410	While stopping, setting and starting an I/O watcher in the same iteration
391	will result in some caching, there is still a system call per such incident	411	will result in some caching, there is still a system call per such
392	(because the fd could point to a different file description now), so its	412	incident (because the same I<file descriptor> could point to a different
393	best to avoid that. Also, C<dup ()>'ed file descriptors might not work	413	I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
394	very well if you register events for both fds.	414	file descriptors might not work very well if you register events for both
395		415	file descriptors.
396	Please note that epoll sometimes generates spurious notifications, so you
397	need to use non-blocking I/O or other means to avoid blocking when no data
398	(or space) is available.
399		416
400	Best performance from this backend is achieved by not unregistering all	417	Best performance from this backend is achieved by not unregistering all
401	watchers for a file descriptor until it has been closed, if possible,	418	watchers for a file descriptor until it has been closed, if possible,
402	i.e. keep at least one watcher active per fd at all times. Stopping and	419	i.e. keep at least one watcher active per fd at all times. Stopping and
403	starting a watcher (without re-setting it) also usually doesn't cause	420	starting a watcher (without re-setting it) also usually doesn't cause
404	extra overhead.	421	extra overhead. A fork can both result in spurious notifications as well
		422	as in libev having to destroy and recreate the epoll object, which can
		423	take considerable time and thus should be avoided.
		424
		425	All this means that, in practice, C<EVBACKEND_SELECT> can be as fast or
		426	faster than epoll for maybe up to a hundred file descriptors, depending on
		427	the usage. So sad.
405		428
406	While nominally embeddable in other event loops, this feature is broken in	429	While nominally embeddable in other event loops, this feature is broken in
407	all kernel versions tested so far.	430	all kernel versions tested so far.
408		431
409	This backend maps C<EV_READ> and C<EV_WRITE> in the same way as	432	This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
410	C<EVBACKEND_POLL>.	433	C<EVBACKEND_POLL>.
411		434
412	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)	435	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
413		436
414	Kqueue deserves special mention, as at the time of this writing, it was	437	Kqueue deserves special mention, as at the time of this writing, it
415	broken on all BSDs except NetBSD (usually it doesn't work reliably with	438	was broken on all BSDs except NetBSD (usually it doesn't work reliably
416	anything but sockets and pipes, except on Darwin, where of course it's	439	with anything but sockets and pipes, except on Darwin, where of course
417	completely useless). For this reason it's not being "auto-detected" unless	440	it's completely useless). Unlike epoll, however, whose brokenness
418	you explicitly specify it in the flags (i.e. using C<EVBACKEND_KQUEUE>) or	441	is by design, these kqueue bugs can (and eventually will) be fixed
419	libev was compiled on a known-to-be-good (-enough) system like NetBSD.	442	without API changes to existing programs. For this reason it's not being
		443	"auto-detected" unless you explicitly specify it in the flags (i.e. using
		444	C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough)
		445	system like NetBSD.
420		446
421	You still can embed kqueue into a normal poll or select backend and use it	447	You still can embed kqueue into a normal poll or select backend and use it
422	only for sockets (after having made sure that sockets work with kqueue on	448	only for sockets (after having made sure that sockets work with kqueue on
423	the target platform). See C<ev_embed> watchers for more info.	449	the target platform). See C<ev_embed> watchers for more info.
424		450
425	It scales in the same way as the epoll backend, but the interface to the	451	It scales in the same way as the epoll backend, but the interface to the
426	kernel is more efficient (which says nothing about its actual speed, of	452	kernel is more efficient (which says nothing about its actual speed, of
427	course). While stopping, setting and starting an I/O watcher does never	453	course). While stopping, setting and starting an I/O watcher does never
428	cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to	454	cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to
429	two event changes per incident. Support for C<fork ()> is very bad and it	455	two event changes per incident. Support for C<fork ()> is very bad (but
430	drops fds silently in similarly hard-to-detect cases.	456	sane, unlike epoll) and it drops fds silently in similarly hard-to-detect
		457	cases
431		458
432	This backend usually performs well under most conditions.	459	This backend usually performs well under most conditions.
433		460
434	While nominally embeddable in other event loops, this doesn't work	461	While nominally embeddable in other event loops, this doesn't work
435	everywhere, so you might need to test for this. And since it is broken	462	everywhere, so you might need to test for this. And since it is broken
…		…
464	might perform better.	491	might perform better.
465		492
466	On the positive side, with the exception of the spurious readiness	493	On the positive side, with the exception of the spurious readiness
467	notifications, this backend actually performed fully to specification	494	notifications, this backend actually performed fully to specification
468	in all tests and is fully embeddable, which is a rare feat among the	495	in all tests and is fully embeddable, which is a rare feat among the
469	OS-specific backends.	496	OS-specific backends (I vastly prefer correctness over speed hacks).
470		497
471	This backend maps C<EV_READ> and C<EV_WRITE> in the same way as	498	This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
472	C<EVBACKEND_POLL>.	499	C<EVBACKEND_POLL>.
473		500
474	=item C<EVBACKEND_ALL>	501	=item C<EVBACKEND_ALL>
…		…
527	responsibility to either stop all watchers cleanly yourself I<before>	554	responsibility to either stop all watchers cleanly yourself I<before>
528	calling this function, or cope with the fact afterwards (which is usually	555	calling this function, or cope with the fact afterwards (which is usually
529	the easiest thing, you can just ignore the watchers and/or C<free ()> them	556	the easiest thing, you can just ignore the watchers and/or C<free ()> them
530	for example).	557	for example).
531		558
532	Note that certain global state, such as signal state, will not be freed by	559	Note that certain global state, such as signal state (and installed signal
533	this function, and related watchers (such as signal and child watchers)	560	handlers), will not be freed by this function, and related watchers (such
534	would need to be stopped manually.	561	as signal and child watchers) would need to be stopped manually.
535		562
536	In general it is not advisable to call this function except in the	563	In general it is not advisable to call this function except in the
537	rare occasion where you really need to free e.g. the signal handling	564	rare occasion where you really need to free e.g. the signal handling
538	pipe fds. If you need dynamically allocated loops it is better to use	565	pipe fds. If you need dynamically allocated loops it is better to use
539	C<ev_loop_new> and C<ev_loop_destroy>).	566	C<ev_loop_new> and C<ev_loop_destroy>).
…		…
631	the loop.	658	the loop.
632		659
633	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	660	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if
634	necessary) and will handle those and any already outstanding ones. It	661	necessary) and will handle those and any already outstanding ones. It
635	will block your process until at least one new event arrives (which could	662	will block your process until at least one new event arrives (which could
636	be an event internal to libev itself, so there is no guarentee that a	663	be an event internal to libev itself, so there is no guarantee that a
637	user-registered callback will be called), and will return after one	664	user-registered callback will be called), and will return after one
638	iteration of the loop.	665	iteration of the loop.
639		666
640	This is useful if you are waiting for some external event in conjunction	667	This is useful if you are waiting for some external event in conjunction
641	with something not expressible using other libev watchers (i.e. "roll your	668	with something not expressible using other libev watchers (i.e. "roll your
…		…
768	they fire on, say, one-second boundaries only.	795	they fire on, say, one-second boundaries only.
769		796
770	=item ev_loop_verify (loop)	797	=item ev_loop_verify (loop)
771		798
772	This function only does something when C<EV_VERIFY> support has been	799	This function only does something when C<EV_VERIFY> support has been
773	compiled in. which is the default for non-minimal builds. It tries to go	800	compiled in, which is the default for non-minimal builds. It tries to go
774	through all internal structures and checks them for validity. If anything	801	through all internal structures and checks them for validity. If anything
775	is found to be inconsistent, it will print an error message to standard	802	is found to be inconsistent, it will print an error message to standard
776	error and call C<abort ()>.	803	error and call C<abort ()>.
777		804
778	This can be used to catch bugs inside libev itself: under normal	805	This can be used to catch bugs inside libev itself: under normal
…		…
781		808
782	=back	809	=back
783		810
784		811
785	=head1 ANATOMY OF A WATCHER	812	=head1 ANATOMY OF A WATCHER
		813
		814	In the following description, uppercase C<TYPE> in names stands for the
		815	watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
		816	watchers and C<ev_io_start> for I/O watchers.
786		817
787	A watcher is a structure that you create and register to record your	818	A watcher is a structure that you create and register to record your
788	interest in some event. For instance, if you want to wait for STDIN to	819	interest in some event. For instance, if you want to wait for STDIN to
789	become readable, you would create an C<ev_io> watcher for that:	820	become readable, you would create an C<ev_io> watcher for that:
790		821
…		…
793	ev_io_stop (w);	824	ev_io_stop (w);
794	ev_unloop (loop, EVUNLOOP_ALL);	825	ev_unloop (loop, EVUNLOOP_ALL);
795	}	826	}
796		827
797	struct ev_loop *loop = ev_default_loop (0);	828	struct ev_loop *loop = ev_default_loop (0);
		829
798	ev_io stdin_watcher;	830	ev_io stdin_watcher;
		831
799	ev_init (&stdin_watcher, my_cb);	832	ev_init (&stdin_watcher, my_cb);
800	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	833	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
801	ev_io_start (loop, &stdin_watcher);	834	ev_io_start (loop, &stdin_watcher);
		835
802	ev_loop (loop, 0);	836	ev_loop (loop, 0);
803		837
804	As you can see, you are responsible for allocating the memory for your	838	As you can see, you are responsible for allocating the memory for your
805	watcher structures (and it is usually a bad idea to do this on the stack,	839	watcher structures (and it is I<usually> a bad idea to do this on the
806	although this can sometimes be quite valid).	840	stack).
		841
		842	Each watcher has an associated watcher structure (called C<struct ev_TYPE>
		843	or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
807		844
808	Each watcher structure must be initialised by a call to C<ev_init	845	Each watcher structure must be initialised by a call to C<ev_init
809	(watcher *, callback)>, which expects a callback to be provided. This	846	(watcher *, callback)>, which expects a callback to be provided. This
810	callback gets invoked each time the event occurs (or, in the case of I/O	847	callback gets invoked each time the event occurs (or, in the case of I/O
811	watchers, each time the event loop detects that the file descriptor given	848	watchers, each time the event loop detects that the file descriptor given
812	is readable and/or writable).	849	is readable and/or writable).
813		850
814	Each watcher type has its own C<< ev_<type>_set (watcher *, ...) >> macro	851	Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
815	with arguments specific to this watcher type. There is also a macro	852	macro to configure it, with arguments specific to the watcher type. There
816	to combine initialisation and setting in one call: C<< ev_<type>_init	853	is also a macro to combine initialisation and setting in one call: C<<
817	(watcher *, callback, ...) >>.	854	ev_TYPE_init (watcher *, callback, ...) >>.
818		855
819	To make the watcher actually watch out for events, you have to start it	856	To make the watcher actually watch out for events, you have to start it
820	with a watcher-specific start function (C<< ev_<type>_start (loop, watcher	857	with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher
821	*) >>), and you can stop watching for events at any time by calling the	858	*) >>), and you can stop watching for events at any time by calling the
822	corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>.	859	corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>.
823		860
824	As long as your watcher is active (has been started but not stopped) you	861	As long as your watcher is active (has been started but not stopped) you
825	must not touch the values stored in it. Most specifically you must never	862	must not touch the values stored in it. Most specifically you must never
826	reinitialise it or call its C<set> macro.	863	reinitialise it or call its C<ev_TYPE_set> macro.
827		864
828	Each and every callback receives the event loop pointer as first, the	865	Each and every callback receives the event loop pointer as first, the
829	registered watcher structure as second, and a bitset of received events as	866	registered watcher structure as second, and a bitset of received events as
830	third argument.	867	third argument.
831		868
…		…
912		949
913	=back	950	=back
914		951
915	=head2 GENERIC WATCHER FUNCTIONS	952	=head2 GENERIC WATCHER FUNCTIONS
916		953
917	In the following description, C<TYPE> stands for the watcher type,
918	e.g. C<timer> for C<ev_timer> watchers and C<io> for C<ev_io> watchers.
919
920	=over 4	954	=over 4
921		955
922	=item C<ev_init> (ev_TYPE *watcher, callback)	956	=item C<ev_init> (ev_TYPE *watcher, callback)
923		957
924	This macro initialises the generic portion of a watcher. The contents	958	This macro initialises the generic portion of a watcher. The contents
…		…
1032	The default priority used by watchers when no priority has been set is	1066	The default priority used by watchers when no priority has been set is
1033	always C<0>, which is supposed to not be too high and not be too low :).	1067	always C<0>, which is supposed to not be too high and not be too low :).
1034		1068
1035	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is	1069	Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
1036	fine, as long as you do not mind that the priority value you query might	1070	fine, as long as you do not mind that the priority value you query might
1037	or might not have been adjusted to be within valid range.	1071	or might not have been clamped to the valid range.
1038		1072
1039	=item ev_invoke (loop, ev_TYPE *watcher, int revents)	1073	=item ev_invoke (loop, ev_TYPE *watcher, int revents)
1040		1074
1041	Invoke the C<watcher> with the given C<loop> and C<revents>. Neither	1075	Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
1042	C<loop> nor C<revents> need to be valid as long as the watcher callback	1076	C<loop> nor C<revents> need to be valid as long as the watcher callback
…		…
1288	passed, but if multiple timers become ready during the same loop iteration	1322	passed, but if multiple timers become ready during the same loop iteration
1289	then order of execution is undefined.	1323	then order of execution is undefined.
1290		1324
1291	=head3 Be smart about timeouts	1325	=head3 Be smart about timeouts
1292		1326
1293	Many real-world problems invole some kind of time-out, usually for error	1327	Many real-world problems involve some kind of timeout, usually for error
1294	recovery. A typical example is an HTTP request - if the other side hangs,	1328	recovery. A typical example is an HTTP request - if the other side hangs,
1295	you want to raise some error after a while.	1329	you want to raise some error after a while.
1296		1330
1297	Here are some ways on how to handle this problem, from simple and	1331	What follows are some ways to handle this problem, from obvious and
1298	inefficient to very efficient.	1332	inefficient to smart and efficient.
1299		1333
1300	In the following examples a 60 second activity timeout is assumed - a	1334	In the following, a 60 second activity timeout is assumed - a timeout that
1301	timeout that gets reset to 60 seconds each time some data ("a lifesign")	1335	gets reset to 60 seconds each time there is activity (e.g. each time some
1302	was received.	1336	data or other life sign was received).
1303		1337
1304	=over 4	1338	=over 4
1305		1339
1306	=item 1. Use a timer and stop, reinitialise, start it on activity.	1340	=item 1. Use a timer and stop, reinitialise and start it on activity.
1307		1341
1308	This is the most obvious, but not the most simple way: In the beginning,	1342	This is the most obvious, but not the most simple way: In the beginning,
1309	start the watcher:	1343	start the watcher:
1310		1344
1311	ev_timer_init (timer, callback, 60., 0.);	1345	ev_timer_init (timer, callback, 60., 0.);
1312	ev_timer_start (loop, timer);	1346	ev_timer_start (loop, timer);
1313		1347
1314	Then, each time there is some activity, C<ev_timer_stop> the timer,	1348	Then, each time there is some activity, C<ev_timer_stop> it, initialise it
1315	initialise it again, and start it:	1349	and start it again:
1316		1350
1317	ev_timer_stop (loop, timer);	1351	ev_timer_stop (loop, timer);
1318	ev_timer_set (timer, 60., 0.);	1352	ev_timer_set (timer, 60., 0.);
1319	ev_timer_start (loop, timer);	1353	ev_timer_start (loop, timer);
1320		1354
1321	This is relatively simple to implement, but means that each time there	1355	This is relatively simple to implement, but means that each time there is
1322	is some activity, libev will first have to remove the timer from it's	1356	some activity, libev will first have to remove the timer from its internal
1323	internal data strcuture and then add it again.	1357	data structure and then add it again. Libev tries to be fast, but it's
		1358	still not a constant-time operation.
1324		1359
1325	=item 2. Use a timer and re-start it with C<ev_timer_again> inactivity.	1360	=item 2. Use a timer and re-start it with C<ev_timer_again> inactivity.
1326		1361
1327	This is the easiest way, and involves using C<ev_timer_again> instead of	1362	This is the easiest way, and involves using C<ev_timer_again> instead of
1328	C<ev_timer_start>.	1363	C<ev_timer_start>.
1329		1364
1330	For this, configure an C<ev_timer> with a C<repeat> value of C<60> and	1365	To implement this, configure an C<ev_timer> with a C<repeat> value
1331	then call C<ev_timer_again> at start and each time you successfully read	1366	of C<60> and then call C<ev_timer_again> at start and each time you
1332	or write some data. If you go into an idle state where you do not expect	1367	successfully read or write some data. If you go into an idle state where
1333	data to travel on the socket, you can C<ev_timer_stop> the timer, and	1368	you do not expect data to travel on the socket, you can C<ev_timer_stop>
1334	C<ev_timer_again> will automatically restart it if need be.	1369	the timer, and C<ev_timer_again> will automatically restart it if need be.
1335		1370
1336	That means you can ignore the C<after> value and C<ev_timer_start>	1371	That means you can ignore both the C<ev_timer_start> function and the
1337	altogether and only ever use the C<repeat> value and C<ev_timer_again>.	1372	C<after> argument to C<ev_timer_set>, and only ever use the C<repeat>
		1373	member and C<ev_timer_again>.
1338		1374
1339	At start:	1375	At start:
1340		1376
1341	ev_timer_init (timer, callback, 0., 60.);	1377	ev_timer_init (timer, callback);
		1378	timer->repeat = 60.;
1342	ev_timer_again (loop, timer);	1379	ev_timer_again (loop, timer);
1343		1380
1344	Each time you receive some data:	1381	Each time there is some activity:
1345		1382
1346	ev_timer_again (loop, timer);	1383	ev_timer_again (loop, timer);
1347		1384
1348	It is even possible to change the time-out on the fly:	1385	It is even possible to change the time-out on the fly, regardless of
		1386	whether the watcher is active or not:
1349		1387
1350	timer->repeat = 30.;	1388	timer->repeat = 30.;
1351	ev_timer_again (loop, timer);	1389	ev_timer_again (loop, timer);
1352		1390
1353	This is slightly more efficient then stopping/starting the timer each time	1391	This is slightly more efficient then stopping/starting the timer each time
1354	you want to modify its timeout value, as libev does not have to completely	1392	you want to modify its timeout value, as libev does not have to completely
1355	remove and re-insert the timer from/into it's internal data structure.	1393	remove and re-insert the timer from/into its internal data structure.
		1394
		1395	It is, however, even simpler than the "obvious" way to do it.
1356		1396
1357	=item 3. Let the timer time out, but then re-arm it as required.	1397	=item 3. Let the timer time out, but then re-arm it as required.
1358		1398
1359	This method is more tricky, but usually most efficient: Most timeouts are	1399	This method is more tricky, but usually most efficient: Most timeouts are
1360	relatively long compared to the loop iteration time - in our example,	1400	relatively long compared to the intervals between other activity - in
1361	within 60 seconds, there are usually many I/O events with associated	1401	our example, within 60 seconds, there are usually many I/O events with
1362	activity resets.	1402	associated activity resets.
1363		1403
1364	In this case, it would be more efficient to leave the C<ev_timer> alone,	1404	In this case, it would be more efficient to leave the C<ev_timer> alone,
1365	but remember the time of last activity, and check for a real timeout only	1405	but remember the time of last activity, and check for a real timeout only
1366	within the callback:	1406	within the callback:
1367		1407
1368	ev_tstamp last_activity; // time of last activity	1408	ev_tstamp last_activity; // time of last activity
1369		1409
1370	static void	1410	static void
1371	callback (EV_P_ ev_timer *w, int revents)	1411	callback (EV_P_ ev_timer *w, int revents)
1372	{	1412	{
1373	ev_tstamp now = ev_now (EV_A);	1413	ev_tstamp now = ev_now (EV_A);
1374	ev_tstamp timeout = last_activity + 60.;	1414	ev_tstamp timeout = last_activity + 60.;
1375		1415
1376	// if last_activity is older than now - timeout, we did time out	1416	// if last_activity + 60. is older than now, we did time out
1377	if (timeout < now)	1417	if (timeout < now)
1378	{	1418	{
1379	// timeout occured, take action	1419	// timeout occured, take action
1380	}	1420	}
1381	else	1421	else
1382	{	1422	{
1383	// callback was invoked, but there was some activity, re-arm	1423	// callback was invoked, but there was some activity, re-arm
1384	// to fire in last_activity + 60.	1424	// the watcher to fire in last_activity + 60, which is
		1425	// guaranteed to be in the future, so "again" is positive:
1385	w->again = timeout - now;	1426	w->repeat = timeout - now;
1386	ev_timer_again (EV_A_ w);	1427	ev_timer_again (EV_A_ w);
1387	}	1428	}
1388	}	1429	}
1389		1430
1390	To summarise the callback: first calculate the real time-out (defined as	1431	To summarise the callback: first calculate the real timeout (defined
1391	"60 seconds after the last activity"), then check if that time has been	1432	as "60 seconds after the last activity"), then check if that time has
1392	reached, which means there was a real timeout. Otherwise the callback was	1433	been reached, which means something I<did>, in fact, time out. Otherwise
1393	invoked too early (timeout is in the future), so re-schedule the timer to	1434	the callback was invoked too early (C<timeout> is in the future), so
1394	fire at that future time.	1435	re-schedule the timer to fire at that future time, to see if maybe we have
		1436	a timeout then.
1395		1437
1396	Note how C<ev_timer_again> is used, taking advantage of the	1438	Note how C<ev_timer_again> is used, taking advantage of the
1397	C<ev_timer_again> optimisation when the timer is already running.	1439	C<ev_timer_again> optimisation when the timer is already running.
1398		1440
1399	This scheme causes more callback invocations (about one every 60 seconds),	1441	This scheme causes more callback invocations (about one every 60 seconds
1400	but virtually no calls to libev to change the timeout.	1442	minus half the average time between activity), but virtually no calls to
		1443	libev to change the timeout.
1401		1444
1402	To start the timer, simply intiialise the watcher and C<last_activity>,	1445	To start the timer, simply initialise the watcher and set C<last_activity>
1403	then call the callback:	1446	to the current time (meaning we just have some activity :), then call the
		1447	callback, which will "do the right thing" and start the timer:
1404		1448
1405	ev_timer_init (timer, callback);	1449	ev_timer_init (timer, callback);
1406	last_activity = ev_now (loop);	1450	last_activity = ev_now (loop);
1407	callback (loop, timer, EV_TIMEOUT);	1451	callback (loop, timer, EV_TIMEOUT);
1408		1452
1409	And when there is some activity, simply remember the time in	1453	And when there is some activity, simply store the current time in
1410	C<last_activity>:	1454	C<last_activity>, no libev calls at all:
1411		1455
1412	last_actiivty = ev_now (loop);	1456	last_actiivty = ev_now (loop);
1413		1457
1414	This technique is slightly more complex, but in most cases where the	1458	This technique is slightly more complex, but in most cases where the
1415	time-out is unlikely to be triggered, much more efficient.	1459	time-out is unlikely to be triggered, much more efficient.
1416		1460
		1461	Changing the timeout is trivial as well (if it isn't hard-coded in the
		1462	callback :) - just change the timeout and invoke the callback, which will
		1463	fix things for you.
		1464
		1465	=item 4. Wee, just use a double-linked list for your timeouts.
		1466
		1467	If there is not one request, but many thousands (millions...), all
		1468	employing some kind of timeout with the same timeout value, then one can
		1469	do even better:
		1470
		1471	When starting the timeout, calculate the timeout value and put the timeout
		1472	at the I<end> of the list.
		1473
		1474	Then use an C<ev_timer> to fire when the timeout at the I<beginning> of
		1475	the list is expected to fire (for example, using the technique #3).
		1476
		1477	When there is some activity, remove the timer from the list, recalculate
		1478	the timeout, append it to the end of the list again, and make sure to
		1479	update the C<ev_timer> if it was taken from the beginning of the list.
		1480
		1481	This way, one can manage an unlimited number of timeouts in O(1) time for
		1482	starting, stopping and updating the timers, at the expense of a major
		1483	complication, and having to use a constant timeout. The constant timeout
		1484	ensures that the list stays sorted.
		1485
1417	=back	1486	=back
		1487
		1488	So which method the best?
		1489
		1490	Method #2 is a simple no-brain-required solution that is adequate in most
		1491	situations. Method #3 requires a bit more thinking, but handles many cases
		1492	better, and isn't very complicated either. In most case, choosing either
		1493	one is fine, with #3 being better in typical situations.
		1494
		1495	Method #1 is almost always a bad idea, and buys you nothing. Method #4 is
		1496	rather complicated, but extremely efficient, something that really pays
		1497	off after the first million or so of active timers, i.e. it's usually
		1498	overkill :)
1418		1499
1419	=head3 The special problem of time updates	1500	=head3 The special problem of time updates
1420		1501
1421	Establishing the current time is a costly operation (it usually takes at	1502	Establishing the current time is a costly operation (it usually takes at
1422	least two system calls): EV therefore updates its idea of the current	1503	least two system calls): EV therefore updates its idea of the current
…		…
1852		1933
1853		1934
1854	=head2 C<ev_stat> - did the file attributes just change?	1935	=head2 C<ev_stat> - did the file attributes just change?
1855		1936
1856	This watches a file system path for attribute changes. That is, it calls	1937	This watches a file system path for attribute changes. That is, it calls
1857	C<stat> regularly (or when the OS says it changed) and sees if it changed	1938	C<stat> on that path in regular intervals (or when the OS says it changed)
1858	compared to the last time, invoking the callback if it did.	1939	and sees if it changed compared to the last time, invoking the callback if
		1940	it did.
1859		1941
1860	The path does not need to exist: changing from "path exists" to "path does	1942	The path does not need to exist: changing from "path exists" to "path does
1861	not exist" is a status change like any other. The condition "path does	1943	not exist" is a status change like any other. The condition "path does not
1862	not exist" is signified by the C<st_nlink> field being zero (which is	1944	exist" (or more correctly "path cannot be stat'ed") is signified by the
1863	otherwise always forced to be at least one) and all the other fields of	1945	C<st_nlink> field being zero (which is otherwise always forced to be at
1864	the stat buffer having unspecified contents.	1946	least one) and all the other fields of the stat buffer having unspecified
		1947	contents.
1865		1948
1866	The path I<should> be absolute and I<must not> end in a slash. If it is	1949	The path I<must not> end in a slash or contain special components such as
		1950	C<.> or C<..>. The path I<should> be absolute: If it is relative and
1867	relative and your working directory changes, the behaviour is undefined.	1951	your working directory changes, then the behaviour is undefined.
1868		1952
1869	Since there is no standard kernel interface to do this, the portable	1953	Since there is no portable change notification interface available, the
1870	implementation simply calls C<stat (2)> regularly on the path to see if	1954	portable implementation simply calls C<stat(2)> regularly on the path
1871	it changed somehow. You can specify a recommended polling interval for	1955	to see if it changed somehow. You can specify a recommended polling
1872	this case. If you specify a polling interval of C<0> (highly recommended!)	1956	interval for this case. If you specify a polling interval of C<0> (highly
1873	then a I<suitable, unspecified default> value will be used (which	1957	recommended!) then a I<suitable, unspecified default> value will be used
1874	you can expect to be around five seconds, although this might change	1958	(which you can expect to be around five seconds, although this might
1875	dynamically). Libev will also impose a minimum interval which is currently	1959	change dynamically). Libev will also impose a minimum interval which is
1876	around C<0.1>, but thats usually overkill.	1960	currently around C<0.1>, but that's usually overkill.
1877		1961
1878	This watcher type is not meant for massive numbers of stat watchers,	1962	This watcher type is not meant for massive numbers of stat watchers,
1879	as even with OS-supported change notifications, this can be	1963	as even with OS-supported change notifications, this can be
1880	resource-intensive.	1964	resource-intensive.
1881		1965
1882	At the time of this writing, the only OS-specific interface implemented	1966	At the time of this writing, the only OS-specific interface implemented
1883	is the Linux inotify interface (implementing kqueue support is left as	1967	is the Linux inotify interface (implementing kqueue support is left as an
1884	an exercise for the reader. Note, however, that the author sees no way	1968	exercise for the reader. Note, however, that the author sees no way of
1885	of implementing C<ev_stat> semantics with kqueue).	1969	implementing C<ev_stat> semantics with kqueue, except as a hint).
1886		1970
1887	=head3 ABI Issues (Largefile Support)	1971	=head3 ABI Issues (Largefile Support)
1888		1972
1889	Libev by default (unless the user overrides this) uses the default	1973	Libev by default (unless the user overrides this) uses the default
1890	compilation environment, which means that on systems with large file	1974	compilation environment, which means that on systems with large file
1891	support disabled by default, you get the 32 bit version of the stat	1975	support disabled by default, you get the 32 bit version of the stat
1892	structure. When using the library from programs that change the ABI to	1976	structure. When using the library from programs that change the ABI to
1893	use 64 bit file offsets the programs will fail. In that case you have to	1977	use 64 bit file offsets the programs will fail. In that case you have to
1894	compile libev with the same flags to get binary compatibility. This is	1978	compile libev with the same flags to get binary compatibility. This is
1895	obviously the case with any flags that change the ABI, but the problem is	1979	obviously the case with any flags that change the ABI, but the problem is
1896	most noticeably disabled with ev_stat and large file support.	1980	most noticeably displayed with ev_stat and large file support.
1897		1981
1898	The solution for this is to lobby your distribution maker to make large	1982	The solution for this is to lobby your distribution maker to make large
1899	file interfaces available by default (as e.g. FreeBSD does) and not	1983	file interfaces available by default (as e.g. FreeBSD does) and not
1900	optional. Libev cannot simply switch on large file support because it has	1984	optional. Libev cannot simply switch on large file support because it has
1901	to exchange stat structures with application programs compiled using the	1985	to exchange stat structures with application programs compiled using the
1902	default compilation environment.	1986	default compilation environment.
1903		1987
1904	=head3 Inotify and Kqueue	1988	=head3 Inotify and Kqueue
1905		1989
1906	When C<inotify (7)> support has been compiled into libev (generally	1990	When C<inotify (7)> support has been compiled into libev and present at
1907	only available with Linux 2.6.25 or above due to bugs in earlier	1991	runtime, it will be used to speed up change detection where possible. The
1908	implementations) and present at runtime, it will be used to speed up	1992	inotify descriptor will be created lazily when the first C<ev_stat>
1909	change detection where possible. The inotify descriptor will be created	1993	watcher is being started.
1910	lazily when the first C<ev_stat> watcher is being started.
1911		1994
1912	Inotify presence does not change the semantics of C<ev_stat> watchers	1995	Inotify presence does not change the semantics of C<ev_stat> watchers
1913	except that changes might be detected earlier, and in some cases, to avoid	1996	except that changes might be detected earlier, and in some cases, to avoid
1914	making regular C<stat> calls. Even in the presence of inotify support	1997	making regular C<stat> calls. Even in the presence of inotify support
1915	there are many cases where libev has to resort to regular C<stat> polling,	1998	there are many cases where libev has to resort to regular C<stat> polling,
1916	but as long as the path exists, libev usually gets away without polling.	1999	but as long as kernel 2.6.25 or newer is used (2.6.24 and older have too
		2000	many bugs), the path exists (i.e. stat succeeds), and the path resides on
		2001	a local filesystem (libev currently assumes only ext2/3, jfs, reiserfs and
		2002	xfs are fully working) libev usually gets away without polling.
1917		2003
1918	There is no support for kqueue, as apparently it cannot be used to	2004	There is no support for kqueue, as apparently it cannot be used to
1919	implement this functionality, due to the requirement of having a file	2005	implement this functionality, due to the requirement of having a file
1920	descriptor open on the object at all times, and detecting renames, unlinks	2006	descriptor open on the object at all times, and detecting renames, unlinks
1921	etc. is difficult.	2007	etc. is difficult.
1922		2008
		2009	=head3 C<stat ()> is a synchronous operation
		2010
		2011	Libev doesn't normally do any kind of I/O itself, and so is not blocking
		2012	the process. The exception are C<ev_stat> watchers - those call C<stat
		2013	()>, which is a synchronous operation.
		2014
		2015	For local paths, this usually doesn't matter: unless the system is very
		2016	busy or the intervals between stat's are large, a stat call will be fast,
		2017	as the path data is suually in memory already (except when starting the
		2018	watcher).
		2019
		2020	For networked file systems, calling C<stat ()> can block an indefinite
		2021	time due to network issues, and even under good conditions, a stat call
		2022	often takes multiple milliseconds.
		2023
		2024	Therefore, it is best to avoid using C<ev_stat> watchers on networked
		2025	paths, although this is fully supported by libev.
		2026
1923	=head3 The special problem of stat time resolution	2027	=head3 The special problem of stat time resolution
1924		2028
1925	The C<stat ()> system call only supports full-second resolution portably, and	2029	The C<stat ()> system call only supports full-second resolution portably,
1926	even on systems where the resolution is higher, most file systems still	2030	and even on systems where the resolution is higher, most file systems
1927	only support whole seconds.	2031	still only support whole seconds.
1928		2032
1929	That means that, if the time is the only thing that changes, you can	2033	That means that, if the time is the only thing that changes, you can
1930	easily miss updates: on the first update, C<ev_stat> detects a change and	2034	easily miss updates: on the first update, C<ev_stat> detects a change and
1931	calls your callback, which does something. When there is another update	2035	calls your callback, which does something. When there is another update
1932	within the same second, C<ev_stat> will be unable to detect unless the	2036	within the same second, C<ev_stat> will be unable to detect unless the
…		…
2571	=over 4	2675	=over 4
2572		2676
2573	=item ev_async_init (ev_async *, callback)	2677	=item ev_async_init (ev_async *, callback)
2574		2678
2575	Initialises and configures the async watcher - it has no parameters of any	2679	Initialises and configures the async watcher - it has no parameters of any
2576	kind. There is a C<ev_asynd_set> macro, but using it is utterly pointless,	2680	kind. There is a C<ev_async_set> macro, but using it is utterly pointless,
2577	trust me.	2681	trust me.
2578		2682
2579	=item ev_async_send (loop, ev_async *)	2683	=item ev_async_send (loop, ev_async *)
2580		2684
2581	Sends/signals/activates the given C<ev_async> watcher, that is, feeds	2685	Sends/signals/activates the given C<ev_async> watcher, that is, feeds
…		…
2895	Tony Arcieri has written a ruby extension that offers access to a subset	2999	Tony Arcieri has written a ruby extension that offers access to a subset
2896	of the libev API and adds file handle abstractions, asynchronous DNS and	3000	of the libev API and adds file handle abstractions, asynchronous DNS and
2897	more on top of it. It can be found via gem servers. Its homepage is at	3001	more on top of it. It can be found via gem servers. Its homepage is at
2898	L<http://rev.rubyforge.org/>.	3002	L<http://rev.rubyforge.org/>.
2899		3003
		3004	Roger Pack reports that using the link order C<-lws2_32 -lmsvcrt-ruby-190>
		3005	makes rev work even on mingw.
		3006
2900	=item D	3007	=item D
2901		3008
2902	Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to	3009	Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to
2903	be found at L<http://proj.llucax.com.ar/wiki/evd>.	3010	be found at L<http://proj.llucax.com.ar/wiki/evd>.
		3011
		3012	=item Ocaml
		3013
		3014	Erkki Seppala has written Ocaml bindings for libev, to be found at
		3015	L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
2904		3016
2905	=back	3017	=back
2906		3018
2907		3019
2908	=head1 MACRO MAGIC	3020	=head1 MACRO MAGIC
…		…
3009		3121
3010	#define EV_STANDALONE 1	3122	#define EV_STANDALONE 1
3011	#include "ev.h"	3123	#include "ev.h"
3012		3124
3013	Both header files and implementation files can be compiled with a C++	3125	Both header files and implementation files can be compiled with a C++
3014	compiler (at least, thats a stated goal, and breakage will be treated	3126	compiler (at least, that's a stated goal, and breakage will be treated
3015	as a bug).	3127	as a bug).
3016		3128
3017	You need the following files in your source tree, or in a directory	3129	You need the following files in your source tree, or in a directory
3018	in your include path (e.g. in libev/ when using -Ilibev):	3130	in your include path (e.g. in libev/ when using -Ilibev):
3019		3131
…		…
3075	keeps libev from including F<config.h>, and it also defines dummy	3187	keeps libev from including F<config.h>, and it also defines dummy
3076	implementations for some libevent functions (such as logging, which is not	3188	implementations for some libevent functions (such as logging, which is not
3077	supported). It will also not define any of the structs usually found in	3189	supported). It will also not define any of the structs usually found in
3078	F<event.h> that are not directly supported by the libev core alone.	3190	F<event.h> that are not directly supported by the libev core alone.
3079		3191
		3192	In stanbdalone mode, libev will still try to automatically deduce the
		3193	configuration, but has to be more conservative.
		3194
3080	=item EV_USE_MONOTONIC	3195	=item EV_USE_MONOTONIC
3081		3196
3082	If defined to be C<1>, libev will try to detect the availability of the	3197	If defined to be C<1>, libev will try to detect the availability of the
3083	monotonic clock option at both compile time and runtime. Otherwise no use	3198	monotonic clock option at both compile time and runtime. Otherwise no
3084	of the monotonic clock option will be attempted. If you enable this, you	3199	use of the monotonic clock option will be attempted. If you enable this,
3085	usually have to link against librt or something similar. Enabling it when	3200	you usually have to link against librt or something similar. Enabling it
3086	the functionality isn't available is safe, though, although you have	3201	when the functionality isn't available is safe, though, although you have
3087	to make sure you link against any libraries where the C<clock_gettime>	3202	to make sure you link against any libraries where the C<clock_gettime>
3088	function is hiding in (often F<-lrt>).	3203	function is hiding in (often F<-lrt>). See also C<EV_USE_CLOCK_SYSCALL>.
3089		3204
3090	=item EV_USE_REALTIME	3205	=item EV_USE_REALTIME
3091		3206
3092	If defined to be C<1>, libev will try to detect the availability of the	3207	If defined to be C<1>, libev will try to detect the availability of the
3093	real-time clock option at compile time (and assume its availability at	3208	real-time clock option at compile time (and assume its availability at
3094	runtime if successful). Otherwise no use of the real-time clock option will	3209	runtime if successful). Otherwise no use of the real-time clock option will
3095	be attempted. This effectively replaces C<gettimeofday> by C<clock_get	3210	be attempted. This effectively replaces C<gettimeofday> by C<clock_get
3096	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the	3211	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
3097	note about libraries in the description of C<EV_USE_MONOTONIC>, though.	3212	note about libraries in the description of C<EV_USE_MONOTONIC>, though.
3098		3213
		3214	=item EV_USE_CLOCK_SYSCALL
		3215
		3216	If defined to be C<1>, libev will try to use a direct syscall instead
		3217	of calling the system-provided C<clock_gettime> function. This option
		3218	exists because on GNU/Linux, C<clock_gettime> is in C<librt>, but C<librt>
		3219	unconditionally pulls in C<libpthread>, slowing down single-threaded
		3220	programs needlessly. Using a direct syscall is slightly slower (in
		3221	theory), because no optimised vdso implementation can be used, but avoids
		3222	the pthread dependency. Defaults to C<1> on GNU/Linux with glibc 2.x or
		3223	higher, as it simplifies linking (no need for C<-lrt>).
		3224
3099	=item EV_USE_NANOSLEEP	3225	=item EV_USE_NANOSLEEP
3100		3226
3101	If defined to be C<1>, libev will assume that C<nanosleep ()> is available	3227	If defined to be C<1>, libev will assume that C<nanosleep ()> is available
3102	and will use it for delays. Otherwise it will use C<select ()>.	3228	and will use it for delays. Otherwise it will use C<select ()>.
3103		3229
…		…
3118		3244
3119	=item EV_SELECT_USE_FD_SET	3245	=item EV_SELECT_USE_FD_SET
3120		3246
3121	If defined to C<1>, then the select backend will use the system C<fd_set>	3247	If defined to C<1>, then the select backend will use the system C<fd_set>
3122	structure. This is useful if libev doesn't compile due to a missing	3248	structure. This is useful if libev doesn't compile due to a missing
3123	C<NFDBITS> or C<fd_mask> definition or it mis-guesses the bitset layout on	3249	C<NFDBITS> or C<fd_mask> definition or it mis-guesses the bitset layout
3124	exotic systems. This usually limits the range of file descriptors to some	3250	on exotic systems. This usually limits the range of file descriptors to
3125	low limit such as 1024 or might have other limitations (winsocket only	3251	some low limit such as 1024 or might have other limitations (winsocket
3126	allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation, might	3252	only allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation,
3127	influence the size of the C<fd_set> used.	3253	configures the maximum size of the C<fd_set>.
3128		3254
3129	=item EV_SELECT_IS_WINSOCKET	3255	=item EV_SELECT_IS_WINSOCKET
3130		3256
3131	When defined to C<1>, the select backend will assume that	3257	When defined to C<1>, the select backend will assume that
3132	select/socket/connect etc. don't understand file descriptors but	3258	select/socket/connect etc. don't understand file descriptors but
…		…
3491	loop, as long as you don't confuse yourself). The only exception is that	3617	loop, as long as you don't confuse yourself). The only exception is that
3492	you must not do this from C<ev_periodic> reschedule callbacks.	3618	you must not do this from C<ev_periodic> reschedule callbacks.
3493		3619
3494	Care has been taken to ensure that libev does not keep local state inside	3620	Care has been taken to ensure that libev does not keep local state inside
3495	C<ev_loop>, and other calls do not usually allow for coroutine switches as	3621	C<ev_loop>, and other calls do not usually allow for coroutine switches as
3496	they do not clal any callbacks.	3622	they do not call any callbacks.
3497		3623
3498	=head2 COMPILER WARNINGS	3624	=head2 COMPILER WARNINGS
3499		3625
3500	Depending on your compiler and compiler settings, you might get no or a	3626	Depending on your compiler and compiler settings, you might get no or a
3501	lot of warnings when compiling libev code. Some people are apparently	3627	lot of warnings when compiling libev code. Some people are apparently
…		…
3535	==2274== definitely lost: 0 bytes in 0 blocks.	3661	==2274== definitely lost: 0 bytes in 0 blocks.
3536	==2274== possibly lost: 0 bytes in 0 blocks.	3662	==2274== possibly lost: 0 bytes in 0 blocks.
3537	==2274== still reachable: 256 bytes in 1 blocks.	3663	==2274== still reachable: 256 bytes in 1 blocks.
3538		3664
3539	Then there is no memory leak, just as memory accounted to global variables	3665	Then there is no memory leak, just as memory accounted to global variables
3540	is not a memleak - the memory is still being refernced, and didn't leak.	3666	is not a memleak - the memory is still being referenced, and didn't leak.
3541		3667
3542	Similarly, under some circumstances, valgrind might report kernel bugs	3668	Similarly, under some circumstances, valgrind might report kernel bugs
3543	as if it were a bug in libev (e.g. in realloc or in the poll backend,	3669	as if it were a bug in libev (e.g. in realloc or in the poll backend,
3544	although an acceptable workaround has been found here), or it might be	3670	although an acceptable workaround has been found here), or it might be
3545	confused.	3671	confused.
…		…
3783	=back	3909	=back
3784		3910
3785		3911
3786	=head1 AUTHOR	3912	=head1 AUTHOR
3787		3913
3788	Marc Lehmann <libev@schmorp.de>.	3914	Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson.
3789		3915

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Comparing libev/ev.pod (file contents): Revision 1.198 by root, Thu Oct 23 06:30:48 2008 UTC vs. Revision 1.220 by root, Thu Nov 20 11:25:15 2008 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.198 by root, Thu Oct 23 06:30:48 2008 UTC vs.
Revision 1.220 by root, Thu Nov 20 11:25:15 2008 UTC