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

Comparing libev/ev.pod (file contents):
Revision 1.95 by root, Fri Dec 21 05:10:01 2007 UTC vs.
Revision 1.114 by root, Mon Dec 31 01:31:30 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	9	=head2 EXAMPLE PROGRAM
10		10
11	#include <ev.h>	11	#include <ev.h>
12		12
13	ev_io stdin_watcher;	13	ev_io stdin_watcher;
14	ev_timer timeout_watcher;	14	ev_timer timeout_watcher;
…		…
65	You register interest in certain events by registering so-called I<event	65	You register interest in certain events by registering so-called I<event
66	watchers>, which are relatively small C structures you initialise with the	66	watchers>, which are relatively small C structures you initialise with the
67	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
68	watcher.	68	watcher.
69		69
70	=head1 FEATURES	70	=head2 FEATURES
71		71
72	Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the	72	Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the
73	BSD-specific C<kqueue> and the Solaris-specific event port mechanisms	73	BSD-specific C<kqueue> and the Solaris-specific event port mechanisms
74	for file descriptor events (C<ev_io>), the Linux C<inotify> interface	74	for file descriptor events (C<ev_io>), the Linux C<inotify> interface
75	(for C<ev_stat>), relative timers (C<ev_timer>), absolute timers	75	(for C<ev_stat>), relative timers (C<ev_timer>), absolute timers
…		…
82		82
83	It also is quite fast (see this	83	It also is quite fast (see this
84	L<benchmark\|http://libev.schmorp.de/bench.html> comparing it to libevent	84	L<benchmark\|http://libev.schmorp.de/bench.html> comparing it to libevent
85	for example).	85	for example).
86		86
87	=head1 CONVENTIONS	87	=head2 CONVENTIONS
88		88
89	Libev is very configurable. In this manual the default configuration will	89	Libev is very configurable. In this manual the default configuration will
90	be described, which supports multiple event loops. For more info about	90	be described, which supports multiple event loops. For more info about
91	various configuration options please have a look at B<EMBED> section in	91	various configuration options please have a look at B<EMBED> section in
92	this manual. If libev was configured without support for multiple event	92	this manual. If libev was configured without support for multiple event
93	loops, then all functions taking an initial argument of name C<loop>	93	loops, then all functions taking an initial argument of name C<loop>
94	(which is always of type C<struct ev_loop *>) will not have this argument.	94	(which is always of type C<struct ev_loop *>) will not have this argument.
95		95
96	=head1 TIME REPRESENTATION	96	=head2 TIME REPRESENTATION
97		97
98	Libev represents time as a single floating point number, representing the	98	Libev represents time as a single floating point number, representing the
99	(fractional) number of seconds since the (POSIX) epoch (somewhere near	99	(fractional) number of seconds since the (POSIX) epoch (somewhere near
100	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
101	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
…		…
115		115
116	Returns the current time as libev would use it. Please note that the	116	Returns the current time as libev would use it. Please note that the
117	C<ev_now> function is usually faster and also often returns the timestamp	117	C<ev_now> function is usually faster and also often returns the timestamp
118	you actually want to know.	118	you actually want to know.
119		119
		120	=item ev_sleep (ev_tstamp interval)
		121
		122	Sleep for the given interval: The current thread will be blocked until
		123	either it is interrupted or the given time interval has passed. Basically
		124	this is a subsecond-resolution C<sleep ()>.
		125
120	=item int ev_version_major ()	126	=item int ev_version_major ()
121		127
122	=item int ev_version_minor ()	128	=item int ev_version_minor ()
123		129
124	You can find out the major and minor ABI version numbers of the library	130	You can find out the major and minor ABI version numbers of the library
…		…
300	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	306	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
301		307
302	This is your standard select(2) backend. Not I<completely> standard, as	308	This is your standard select(2) backend. Not I<completely> standard, as
303	libev tries to roll its own fd_set with no limits on the number of fds,	309	libev tries to roll its own fd_set with no limits on the number of fds,
304	but if that fails, expect a fairly low limit on the number of fds when	310	but if that fails, expect a fairly low limit on the number of fds when
305	using this backend. It doesn't scale too well (O(highest_fd)), but its usually	311	using this backend. It doesn't scale too well (O(highest_fd)), but its
306	the fastest backend for a low number of fds.	312	usually the fastest backend for a low number of (low-numbered :) fds.
		313
		314	To get good performance out of this backend you need a high amount of
		315	parallelity (most of the file descriptors should be busy). If you are
		316	writing a server, you should C<accept ()> in a loop to accept as many
		317	connections as possible during one iteration. You might also want to have
		318	a look at C<ev_set_io_collect_interval ()> to increase the amount of
		319	readyness notifications you get per iteration.
307		320
308	=item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows)	321	=item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows)
309		322
310	And this is your standard poll(2) backend. It's more complicated than	323	And this is your standard poll(2) backend. It's more complicated
311	select, but handles sparse fds better and has no artificial limit on the	324	than select, but handles sparse fds better and has no artificial
312	number of fds you can use (except it will slow down considerably with a	325	limit on the number of fds you can use (except it will slow down
313	lot of inactive fds). It scales similarly to select, i.e. O(total_fds).	326	considerably with a lot of inactive fds). It scales similarly to select,
		327	i.e. O(total_fds). See the entry for C<EVBACKEND_SELECT>, above, for
		328	performance tips.
314		329
315	=item C<EVBACKEND_EPOLL> (value 4, Linux)	330	=item C<EVBACKEND_EPOLL> (value 4, Linux)
316		331
317	For few fds, this backend is a bit little slower than poll and select,	332	For few fds, this backend is a bit little slower than poll and select,
318	but it scales phenomenally better. While poll and select usually scale	333	but it scales phenomenally better. While poll and select usually scale
319	like O(total_fds) where n is the total number of fds (or the highest fd),	334	like O(total_fds) where n is the total number of fds (or the highest fd),
320	epoll scales either O(1) or O(active_fds). The epoll design has a number	335	epoll scales either O(1) or O(active_fds). The epoll design has a number
321	of shortcomings, such as silently dropping events in some hard-to-detect	336	of shortcomings, such as silently dropping events in some hard-to-detect
322	cases and rewuiring a syscall per fd change, no fork support and bad	337	cases and rewiring a syscall per fd change, no fork support and bad
323	support for dup:	338	support for dup.
324		339
325	While stopping, setting and starting an I/O watcher in the same iteration	340	While stopping, setting and starting an I/O watcher in the same iteration
326	will result in some caching, there is still a syscall per such incident	341	will result in some caching, there is still a syscall per such incident
327	(because the fd could point to a different file description now), so its	342	(because the fd could point to a different file description now), so its
328	best to avoid that. Also, C<dup ()>'ed file descriptors might not work	343	best to avoid that. Also, C<dup ()>'ed file descriptors might not work
…		…
330		345
331	Please note that epoll sometimes generates spurious notifications, so you	346	Please note that epoll sometimes generates spurious notifications, so you
332	need to use non-blocking I/O or other means to avoid blocking when no data	347	need to use non-blocking I/O or other means to avoid blocking when no data
333	(or space) is available.	348	(or space) is available.
334		349
		350	Best performance from this backend is achieved by not unregistering all
		351	watchers for a file descriptor until it has been closed, if possible, i.e.
		352	keep at least one watcher active per fd at all times.
		353
		354	While nominally embeddeble in other event loops, this feature is broken in
		355	all kernel versions tested so far.
		356
335	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)	357	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
336		358
337	Kqueue deserves special mention, as at the time of this writing, it	359	Kqueue deserves special mention, as at the time of this writing, it
338	was broken on I<all> BSDs (usually it doesn't work with anything but	360	was broken on all BSDs except NetBSD (usually it doesn't work reliably
339	sockets and pipes, except on Darwin, where of course it's completely	361	with anything but sockets and pipes, except on Darwin, where of course
340	useless. On NetBSD, it seems to work for all the FD types I tested, so it
341	is used by default there). For this reason it's not being "autodetected"	362	it's completely useless). For this reason it's not being "autodetected"
342	unless you explicitly specify it explicitly in the flags (i.e. using	363	unless you explicitly specify it explicitly in the flags (i.e. using
343	C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough)	364	C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough)
344	system like NetBSD.	365	system like NetBSD.
345		366
		367	You still can embed kqueue into a normal poll or select backend and use it
		368	only for sockets (after having made sure that sockets work with kqueue on
		369	the target platform). See C<ev_embed> watchers for more info.
		370
346	It scales in the same way as the epoll backend, but the interface to the	371	It scales in the same way as the epoll backend, but the interface to the
347	kernel is more efficient (which says nothing about its actual speed,	372	kernel is more efficient (which says nothing about its actual speed, of
348	of course). While stopping, setting and starting an I/O watcher does	373	course). While stopping, setting and starting an I/O watcher does never
349	never cause an extra syscall as with epoll, it still adds up to two event	374	cause an extra syscall as with C<EVBACKEND_EPOLL>, it still adds up to
350	changes per incident, support for C<fork ()> is very bad and it drops fds	375	two event changes per incident, support for C<fork ()> is very bad and it
351	silently in similarly hard-to-detetc cases.	376	drops fds silently in similarly hard-to-detect cases.
		377
		378	This backend usually performs well under most conditions.
		379
		380	While nominally embeddable in other event loops, this doesn't work
		381	everywhere, so you might need to test for this. And since it is broken
		382	almost everywhere, you should only use it when you have a lot of sockets
		383	(for which it usually works), by embedding it into another event loop
		384	(e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>) and using it only for
		385	sockets.
352		386
353	=item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8)	387	=item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8)
354		388
355	This is not implemented yet (and might never be).	389	This is not implemented yet (and might never be, unless you send me an
		390	implementation). According to reports, C</dev/poll> only supports sockets
		391	and is not embeddable, which would limit the usefulness of this backend
		392	immensely.
356		393
357	=item C<EVBACKEND_PORT> (value 32, Solaris 10)	394	=item C<EVBACKEND_PORT> (value 32, Solaris 10)
358		395
359	This uses the Solaris 10 event port mechanism. As with everything on Solaris,	396	This uses the Solaris 10 event port mechanism. As with everything on Solaris,
360	it's really slow, but it still scales very well (O(active_fds)).	397	it's really slow, but it still scales very well (O(active_fds)).
361		398
362	Please note that solaris event ports can deliver a lot of spurious	399	Please note that solaris event ports can deliver a lot of spurious
363	notifications, so you need to use non-blocking I/O or other means to avoid	400	notifications, so you need to use non-blocking I/O or other means to avoid
364	blocking when no data (or space) is available.	401	blocking when no data (or space) is available.
365		402
		403	While this backend scales well, it requires one system call per active
		404	file descriptor per loop iteration. For small and medium numbers of file
		405	descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend
		406	might perform better.
		407
366	=item C<EVBACKEND_ALL>	408	=item C<EVBACKEND_ALL>
367		409
368	Try all backends (even potentially broken ones that wouldn't be tried	410	Try all backends (even potentially broken ones that wouldn't be tried
369	with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as	411	with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as
370	C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.	412	C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.
		413
		414	It is definitely not recommended to use this flag.
371		415
372	=back	416	=back
373		417
374	If one or more of these are ored into the flags value, then only these	418	If one or more of these are ored into the flags value, then only these
375	backends will be tried (in the reverse order as given here). If none are	419	backends will be tried (in the reverse order as given here). If none are
…		…
507	usually a better approach for this kind of thing.	551	usually a better approach for this kind of thing.
508		552
509	Here are the gory details of what C<ev_loop> does:	553	Here are the gory details of what C<ev_loop> does:
510		554
511	- Before the first iteration, call any pending watchers.	555	- Before the first iteration, call any pending watchers.
512	* If there are no active watchers (reference count is zero), return.	556	* If EVFLAG_FORKCHECK was used, check for a fork.
513	- Queue all prepare watchers and then call all outstanding watchers.	557	- If a fork was detected, queue and call all fork watchers.
		558	- Queue and call all prepare watchers.
514	- If we have been forked, recreate the kernel state.	559	- If we have been forked, recreate the kernel state.
515	- Update the kernel state with all outstanding changes.	560	- Update the kernel state with all outstanding changes.
516	- Update the "event loop time".	561	- Update the "event loop time".
517	- Calculate for how long to block.	562	- Calculate for how long to sleep or block, if at all
		563	(active idle watchers, EVLOOP_NONBLOCK or not having
		564	any active watchers at all will result in not sleeping).
		565	- Sleep if the I/O and timer collect interval say so.
518	- Block the process, waiting for any events.	566	- Block the process, waiting for any events.
519	- Queue all outstanding I/O (fd) events.	567	- Queue all outstanding I/O (fd) events.
520	- Update the "event loop time" and do time jump handling.	568	- Update the "event loop time" and do time jump handling.
521	- Queue all outstanding timers.	569	- Queue all outstanding timers.
522	- Queue all outstanding periodics.	570	- Queue all outstanding periodics.
523	- If no events are pending now, queue all idle watchers.	571	- If no events are pending now, queue all idle watchers.
524	- Queue all check watchers.	572	- Queue all check watchers.
525	- Call all queued watchers in reverse order (i.e. check watchers first).	573	- Call all queued watchers in reverse order (i.e. check watchers first).
526	Signals and child watchers are implemented as I/O watchers, and will	574	Signals and child watchers are implemented as I/O watchers, and will
527	be handled here by queueing them when their watcher gets executed.	575	be handled here by queueing them when their watcher gets executed.
528	- If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	576	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
529	were used, return, otherwise continue with step *.	577	were used, or there are no active watchers, return, otherwise
		578	continue with step *.
530		579
531	Example: Queue some jobs and then loop until no events are outsanding	580	Example: Queue some jobs and then loop until no events are outstanding
532	anymore.	581	anymore.
533		582
534	... queue jobs here, make sure they register event watchers as long	583	... queue jobs here, make sure they register event watchers as long
535	... as they still have work to do (even an idle watcher will do..)	584	... as they still have work to do (even an idle watcher will do..)
536	ev_loop (my_loop, 0);	585	ev_loop (my_loop, 0);
…		…
569	Example: For some weird reason, unregister the above signal handler again.	618	Example: For some weird reason, unregister the above signal handler again.
570		619
571	ev_ref (loop);	620	ev_ref (loop);
572	ev_signal_stop (loop, &exitsig);	621	ev_signal_stop (loop, &exitsig);
573		622
		623	=item ev_set_io_collect_interval (loop, ev_tstamp interval)
		624
		625	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
		626
		627	These advanced functions influence the time that libev will spend waiting
		628	for events. Both are by default C<0>, meaning that libev will try to
		629	invoke timer/periodic callbacks and I/O callbacks with minimum latency.
		630
		631	Setting these to a higher value (the C<interval> I<must> be >= C<0>)
		632	allows libev to delay invocation of I/O and timer/periodic callbacks to
		633	increase efficiency of loop iterations.
		634
		635	The background is that sometimes your program runs just fast enough to
		636	handle one (or very few) event(s) per loop iteration. While this makes
		637	the program responsive, it also wastes a lot of CPU time to poll for new
		638	events, especially with backends like C<select ()> which have a high
		639	overhead for the actual polling but can deliver many events at once.
		640
		641	By setting a higher I<io collect interval> you allow libev to spend more
		642	time collecting I/O events, so you can handle more events per iteration,
		643	at the cost of increasing latency. Timeouts (both C<ev_periodic> and
		644	C<ev_timer>) will be not affected. Setting this to a non-null value will
		645	introduce an additional C<ev_sleep ()> call into most loop iterations.
		646
		647	Likewise, by setting a higher I<timeout collect interval> you allow libev
		648	to spend more time collecting timeouts, at the expense of increased
		649	latency (the watcher callback will be called later). C<ev_io> watchers
		650	will not be affected. Setting this to a non-null value will not introduce
		651	any overhead in libev.
		652
		653	Many (busy) programs can usually benefit by setting the io collect
		654	interval to a value near C<0.1> or so, which is often enough for
		655	interactive servers (of course not for games), likewise for timeouts. It
		656	usually doesn't make much sense to set it to a lower value than C<0.01>,
		657	as this approsaches the timing granularity of most systems.
		658
574	=back	659	=back
575		660
576		661
577	=head1 ANATOMY OF A WATCHER	662	=head1 ANATOMY OF A WATCHER
578		663
…		…
903	In general you can register as many read and/or write event watchers per	988	In general you can register as many read and/or write event watchers per
904	fd as you want (as long as you don't confuse yourself). Setting all file	989	fd as you want (as long as you don't confuse yourself). Setting all file
905	descriptors to non-blocking mode is also usually a good idea (but not	990	descriptors to non-blocking mode is also usually a good idea (but not
906	required if you know what you are doing).	991	required if you know what you are doing).
907		992
908	You have to be careful with dup'ed file descriptors, though. Some backends
909	(the linux epoll backend is a notable example) cannot handle dup'ed file
910	descriptors correctly if you register interest in two or more fds pointing
911	to the same underlying file/socket/etc. description (that is, they share
912	the same underlying "file open").
913
914	If you must do this, then force the use of a known-to-be-good backend	993	If you must do this, then force the use of a known-to-be-good backend
915	(at the time of this writing, this includes only C<EVBACKEND_SELECT> and	994	(at the time of this writing, this includes only C<EVBACKEND_SELECT> and
916	C<EVBACKEND_POLL>).	995	C<EVBACKEND_POLL>).
917		996
918	Another thing you have to watch out for is that it is quite easy to	997	Another thing you have to watch out for is that it is quite easy to
…		…
952	optimisations to libev.	1031	optimisations to libev.
953		1032
954	=head3 The special problem of dup'ed file descriptors	1033	=head3 The special problem of dup'ed file descriptors
955		1034
956	Some backends (e.g. epoll), cannot register events for file descriptors,	1035	Some backends (e.g. epoll), cannot register events for file descriptors,
957	but only events for the underlying file descriptions. That menas when you	1036	but only events for the underlying file descriptions. That means when you
958	have C<dup ()>'ed file descriptors and register events for them, only one	1037	have C<dup ()>'ed file descriptors or weirder constellations, and register
959	file descriptor might actually receive events.	1038	events for them, only one file descriptor might actually receive events.
960		1039
961	There is no workaorund possible except not registering events	1040	There is no workaround possible except not registering events
962	for potentially C<dup ()>'ed file descriptors or to resort to	1041	for potentially C<dup ()>'ed file descriptors, or to resort to
963	C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>.	1042	C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>.
964		1043
965	=head3 The special problem of fork	1044	=head3 The special problem of fork
966		1045
967	Some backends (epoll, kqueue) do not support C<fork ()> at all or exhibit	1046	Some backends (epoll, kqueue) do not support C<fork ()> at all or exhibit
…		…
993	=item int events [read-only]	1072	=item int events [read-only]
994		1073
995	The events being watched.	1074	The events being watched.
996		1075
997	=back	1076	=back
		1077
		1078	=head3 Examples
998		1079
999	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well	1080	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
1000	readable, but only once. Since it is likely line-buffered, you could	1081	readable, but only once. Since it is likely line-buffered, you could
1001	attempt to read a whole line in the callback.	1082	attempt to read a whole line in the callback.
1002		1083
…		…
1100	or C<ev_timer_again> is called and determines the next timeout (if any),	1181	or C<ev_timer_again> is called and determines the next timeout (if any),
1101	which is also when any modifications are taken into account.	1182	which is also when any modifications are taken into account.
1102		1183
1103	=back	1184	=back
1104		1185
		1186	=head3 Examples
		1187
1105	Example: Create a timer that fires after 60 seconds.	1188	Example: Create a timer that fires after 60 seconds.
1106		1189
1107	static void	1190	static void
1108	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	1191	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
1109	{	1192	{
…		…
1266	When active, contains the absolute time that the watcher is supposed to	1349	When active, contains the absolute time that the watcher is supposed to
1267	trigger next.	1350	trigger next.
1268		1351
1269	=back	1352	=back
1270		1353
		1354	=head3 Examples
		1355
1271	Example: Call a callback every hour, or, more precisely, whenever the	1356	Example: Call a callback every hour, or, more precisely, whenever the
1272	system clock is divisible by 3600. The callback invocation times have	1357	system clock is divisible by 3600. The callback invocation times have
1273	potentially a lot of jittering, but good long-term stability.	1358	potentially a lot of jittering, but good long-term stability.
1274		1359
1275	static void	1360	static void
…		…
1366		1451
1367	The process exit/trace status caused by C<rpid> (see your systems	1452	The process exit/trace status caused by C<rpid> (see your systems
1368	C<waitpid> and C<sys/wait.h> documentation for details).	1453	C<waitpid> and C<sys/wait.h> documentation for details).
1369		1454
1370	=back	1455	=back
		1456
		1457	=head3 Examples
1371		1458
1372	Example: Try to exit cleanly on SIGINT and SIGTERM.	1459	Example: Try to exit cleanly on SIGINT and SIGTERM.
1373		1460
1374	static void	1461	static void
1375	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1462	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
…		…
1416	semantics of C<ev_stat> watchers, which means that libev sometimes needs	1503	semantics of C<ev_stat> watchers, which means that libev sometimes needs
1417	to fall back to regular polling again even with inotify, but changes are	1504	to fall back to regular polling again even with inotify, but changes are
1418	usually detected immediately, and if the file exists there will be no	1505	usually detected immediately, and if the file exists there will be no
1419	polling.	1506	polling.
1420		1507
		1508	=head3 Inotify
		1509
		1510	When C<inotify (7)> support has been compiled into libev (generally only
		1511	available on Linux) and present at runtime, it will be used to speed up
		1512	change detection where possible. The inotify descriptor will be created lazily
		1513	when the first C<ev_stat> watcher is being started.
		1514
		1515	Inotify presense does not change the semantics of C<ev_stat> watchers
		1516	except that changes might be detected earlier, and in some cases, to avoid
		1517	making regular C<stat> calls. Even in the presense of inotify support
		1518	there are many cases where libev has to resort to regular C<stat> polling.
		1519
		1520	(There is no support for kqueue, as apparently it cannot be used to
		1521	implement this functionality, due to the requirement of having a file
		1522	descriptor open on the object at all times).
		1523
		1524	=head3 The special problem of stat time resolution
		1525
		1526	The C<stat ()> syscall only supports full-second resolution portably, and
		1527	even on systems where the resolution is higher, many filesystems still
		1528	only support whole seconds.
		1529
		1530	That means that, if the time is the only thing that changes, you might
		1531	miss updates: on the first update, C<ev_stat> detects a change and calls
		1532	your callback, which does something. When there is another update within
		1533	the same second, C<ev_stat> will be unable to detect it.
		1534
		1535	The solution to this is to delay acting on a change for a second (or till
		1536	the next second boundary), using a roughly one-second delay C<ev_timer>
		1537	(C<ev_timer_set (w, 0., 1.01); ev_timer_again (loop, w)>). The C<.01>
		1538	is added to work around small timing inconsistencies of some operating
		1539	systems.
		1540
1421	=head3 Watcher-Specific Functions and Data Members	1541	=head3 Watcher-Specific Functions and Data Members
1422		1542
1423	=over 4	1543	=over 4
1424		1544
1425	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)	1545	=item ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)
…		…
1462	=item const char *path [read-only]	1582	=item const char *path [read-only]
1463		1583
1464	The filesystem path that is being watched.	1584	The filesystem path that is being watched.
1465		1585
1466	=back	1586	=back
		1587
		1588	=head3 Examples
1467		1589
1468	Example: Watch C</etc/passwd> for attribute changes.	1590	Example: Watch C</etc/passwd> for attribute changes.
1469		1591
1470	static void	1592	static void
1471	passwd_cb (struct ev_loop loop, ev_stat w, int revents)	1593	passwd_cb (struct ev_loop loop, ev_stat w, int revents)
…		…
1484	}	1606	}
1485		1607
1486	...	1608	...
1487	ev_stat passwd;	1609	ev_stat passwd;
1488		1610
1489	ev_stat_init (&passwd, passwd_cb, "/etc/passwd");	1611	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
1490	ev_stat_start (loop, &passwd);	1612	ev_stat_start (loop, &passwd);
		1613
		1614	Example: Like above, but additionally use a one-second delay so we do not
		1615	miss updates (however, frequent updates will delay processing, too, so
		1616	one might do the work both on C<ev_stat> callback invocation I<and> on
		1617	C<ev_timer> callback invocation).
		1618
		1619	static ev_stat passwd;
		1620	static ev_timer timer;
		1621
		1622	static void
		1623	timer_cb (EV_P_ ev_timer *w, int revents)
		1624	{
		1625	ev_timer_stop (EV_A_ w);
		1626
		1627	/* now it's one second after the most recent passwd change */
		1628	}
		1629
		1630	static void
		1631	stat_cb (EV_P_ ev_stat *w, int revents)
		1632	{
		1633	/* reset the one-second timer */
		1634	ev_timer_again (EV_A_ &timer);
		1635	}
		1636
		1637	...
		1638	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
		1639	ev_stat_start (loop, &passwd);
		1640	ev_timer_init (&timer, timer_cb, 0., 1.01);
1491		1641
1492		1642
1493	=head2 C<ev_idle> - when you've got nothing better to do...	1643	=head2 C<ev_idle> - when you've got nothing better to do...
1494		1644
1495	Idle watchers trigger events when no other events of the same or higher	1645	Idle watchers trigger events when no other events of the same or higher
…		…
1520	Initialises and configures the idle watcher - it has no parameters of any	1670	Initialises and configures the idle watcher - it has no parameters of any
1521	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,	1671	kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
1522	believe me.	1672	believe me.
1523		1673
1524	=back	1674	=back
		1675
		1676	=head3 Examples
1525		1677
1526	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the	1678	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1527	callback, free it. Also, use no error checking, as usual.	1679	callback, free it. Also, use no error checking, as usual.
1528		1680
1529	static void	1681	static void
…		…
1581		1733
1582	It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>)	1734	It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>)
1583	priority, to ensure that they are being run before any other watchers	1735	priority, to ensure that they are being run before any other watchers
1584	after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers,	1736	after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers,
1585	too) should not activate ("feed") events into libev. While libev fully	1737	too) should not activate ("feed") events into libev. While libev fully
1586	supports this, they will be called before other C<ev_check> watchers did	1738	supports this, they will be called before other C<ev_check> watchers
1587	their job. As C<ev_check> watchers are often used to embed other event	1739	did their job. As C<ev_check> watchers are often used to embed other
1588	loops those other event loops might be in an unusable state until their	1740	(non-libev) event loops those other event loops might be in an unusable
1589	C<ev_check> watcher ran (always remind yourself to coexist peacefully with	1741	state until their C<ev_check> watcher ran (always remind yourself to
1590	others).	1742	coexist peacefully with others).
1591		1743
1592	=head3 Watcher-Specific Functions and Data Members	1744	=head3 Watcher-Specific Functions and Data Members
1593		1745
1594	=over 4	1746	=over 4
1595		1747
…		…
1600	Initialises and configures the prepare or check watcher - they have no	1752	Initialises and configures the prepare or check watcher - they have no
1601	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>	1753	parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>
1602	macros, but using them is utterly, utterly and completely pointless.	1754	macros, but using them is utterly, utterly and completely pointless.
1603		1755
1604	=back	1756	=back
		1757
		1758	=head3 Examples
1605		1759
1606	There are a number of principal ways to embed other event loops or modules	1760	There are a number of principal ways to embed other event loops or modules
1607	into libev. Here are some ideas on how to include libadns into libev	1761	into libev. Here are some ideas on how to include libadns into libev
1608	(there is a Perl module named C<EV::ADNS> that does this, which you could	1762	(there is a Perl module named C<EV::ADNS> that does this, which you could
1609	use for an actually working example. Another Perl module named C<EV::Glib>	1763	use for an actually working example. Another Perl module named C<EV::Glib>
…		…
1734	=head2 C<ev_embed> - when one backend isn't enough...	1888	=head2 C<ev_embed> - when one backend isn't enough...
1735		1889
1736	This is a rather advanced watcher type that lets you embed one event loop	1890	This is a rather advanced watcher type that lets you embed one event loop
1737	into another (currently only C<ev_io> events are supported in the embedded	1891	into another (currently only C<ev_io> events are supported in the embedded
1738	loop, other types of watchers might be handled in a delayed or incorrect	1892	loop, other types of watchers might be handled in a delayed or incorrect
1739	fashion and must not be used). (See portability notes, below).	1893	fashion and must not be used).
1740		1894
1741	There are primarily two reasons you would want that: work around bugs and	1895	There are primarily two reasons you would want that: work around bugs and
1742	prioritise I/O.	1896	prioritise I/O.
1743		1897
1744	As an example for a bug workaround, the kqueue backend might only support	1898	As an example for a bug workaround, the kqueue backend might only support
…		…
1778	portable one.	1932	portable one.
1779		1933
1780	So when you want to use this feature you will always have to be prepared	1934	So when you want to use this feature you will always have to be prepared
1781	that you cannot get an embeddable loop. The recommended way to get around	1935	that you cannot get an embeddable loop. The recommended way to get around
1782	this is to have a separate variables for your embeddable loop, try to	1936	this is to have a separate variables for your embeddable loop, try to
1783	create it, and if that fails, use the normal loop for everything:	1937	create it, and if that fails, use the normal loop for everything.
		1938
		1939	=head3 Watcher-Specific Functions and Data Members
		1940
		1941	=over 4
		1942
		1943	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)
		1944
		1945	=item ev_embed_set (ev_embed , callback, struct ev_loop embedded_loop)
		1946
		1947	Configures the watcher to embed the given loop, which must be
		1948	embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be
		1949	invoked automatically, otherwise it is the responsibility of the callback
		1950	to invoke it (it will continue to be called until the sweep has been done,
		1951	if you do not want thta, you need to temporarily stop the embed watcher).
		1952
		1953	=item ev_embed_sweep (loop, ev_embed *)
		1954
		1955	Make a single, non-blocking sweep over the embedded loop. This works
		1956	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
		1957	apropriate way for embedded loops.
		1958
		1959	=item struct ev_loop *other [read-only]
		1960
		1961	The embedded event loop.
		1962
		1963	=back
		1964
		1965	=head3 Examples
		1966
		1967	Example: Try to get an embeddable event loop and embed it into the default
		1968	event loop. If that is not possible, use the default loop. The default
		1969	loop is stored in C<loop_hi>, while the mebeddable loop is stored in
		1970	C<loop_lo> (which is C<loop_hi> in the acse no embeddable loop can be
		1971	used).
1784		1972
1785	struct ev_loop *loop_hi = ev_default_init (0);	1973	struct ev_loop *loop_hi = ev_default_init (0);
1786	struct ev_loop *loop_lo = 0;	1974	struct ev_loop *loop_lo = 0;
1787	struct ev_embed embed;	1975	struct ev_embed embed;
1788		1976
…		…
1799	ev_embed_start (loop_hi, &embed);	1987	ev_embed_start (loop_hi, &embed);
1800	}	1988	}
1801	else	1989	else
1802	loop_lo = loop_hi;	1990	loop_lo = loop_hi;
1803		1991
1804	=head2 Portability notes	1992	Example: Check if kqueue is available but not recommended and create
		1993	a kqueue backend for use with sockets (which usually work with any
		1994	kqueue implementation). Store the kqueue/socket-only event loop in
		1995	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
1805		1996
1806	Kqueue is nominally embeddable, but this is broken on all BSDs that I	1997	struct ev_loop *loop = ev_default_init (0);
1807	tried, in various ways. Usually the embedded event loop will simply never	1998	struct ev_loop *loop_socket = 0;
1808	receive events, sometimes it will only trigger a few times, sometimes in a	1999	struct ev_embed embed;
1809	loop. Epoll is also nominally embeddable, but many Linux kernel versions	2000
1810	will always eport the epoll fd as ready, even when no events are pending.	2001	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
		2002	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
		2003	{
		2004	ev_embed_init (&embed, 0, loop_socket);
		2005	ev_embed_start (loop, &embed);
		2006	}
1811		2007
1812	While libev allows embedding these backends (they are contained in	2008	if (!loop_socket)
1813	C<ev_embeddable_backends ()>), take extreme care that it will actually	2009	loop_socket = loop;
1814	work.
1815		2010
1816	When in doubt, create a dynamic event loop forced to use sockets (this	2011	// now use loop_socket for all sockets, and loop for everything else
1817	usually works) and possibly another thread and a pipe or so to report to
1818	your main event loop.
1819
1820	=head3 Watcher-Specific Functions and Data Members
1821
1822	=over 4
1823
1824	=item ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)
1825
1826	=item ev_embed_set (ev_embed , callback, struct ev_loop embedded_loop)
1827
1828	Configures the watcher to embed the given loop, which must be
1829	embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be
1830	invoked automatically, otherwise it is the responsibility of the callback
1831	to invoke it (it will continue to be called until the sweep has been done,
1832	if you do not want thta, you need to temporarily stop the embed watcher).
1833
1834	=item ev_embed_sweep (loop, ev_embed *)
1835
1836	Make a single, non-blocking sweep over the embedded loop. This works
1837	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
1838	apropriate way for embedded loops.
1839
1840	=item struct ev_loop *other [read-only]
1841
1842	The embedded event loop.
1843
1844	=back
1845		2012
1846		2013
1847	=head2 C<ev_fork> - the audacity to resume the event loop after a fork	2014	=head2 C<ev_fork> - the audacity to resume the event loop after a fork
1848		2015
1849	Fork watchers are called when a C<fork ()> was detected (usually because	2016	Fork watchers are called when a C<fork ()> was detected (usually because
…		…
2297	runtime if successful). Otherwise no use of the realtime clock option will	2464	runtime if successful). Otherwise no use of the realtime clock option will
2298	be attempted. This effectively replaces C<gettimeofday> by C<clock_get	2465	be attempted. This effectively replaces C<gettimeofday> by C<clock_get
2299	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the	2466	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
2300	note about libraries in the description of C<EV_USE_MONOTONIC>, though.	2467	note about libraries in the description of C<EV_USE_MONOTONIC>, though.
2301		2468
		2469	=item EV_USE_NANOSLEEP
		2470
		2471	If defined to be C<1>, libev will assume that C<nanosleep ()> is available
		2472	and will use it for delays. Otherwise it will use C<select ()>.
		2473
2302	=item EV_USE_SELECT	2474	=item EV_USE_SELECT
2303		2475
2304	If undefined or defined to be C<1>, libev will compile in support for the	2476	If undefined or defined to be C<1>, libev will compile in support for the
2305	C<select>(2) backend. No attempt at autodetection will be done: if no	2477	C<select>(2) backend. No attempt at autodetection will be done: if no
2306	other method takes over, select will be it. Otherwise the select backend	2478	other method takes over, select will be it. Otherwise the select backend
…		…
2323	wants osf handles on win32 (this is the case when the select to	2495	wants osf handles on win32 (this is the case when the select to
2324	be used is the winsock select). This means that it will call	2496	be used is the winsock select). This means that it will call
2325	C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,	2497	C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,
2326	it is assumed that all these functions actually work on fds, even	2498	it is assumed that all these functions actually work on fds, even
2327	on win32. Should not be defined on non-win32 platforms.	2499	on win32. Should not be defined on non-win32 platforms.
		2500
		2501	=item EV_FD_TO_WIN32_HANDLE
		2502
		2503	If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map
		2504	file descriptors to socket handles. When not defining this symbol (the
		2505	default), then libev will call C<_get_osfhandle>, which is usually
		2506	correct. In some cases, programs use their own file descriptor management,
		2507	in which case they can provide this function to map fds to socket handles.
2328		2508
2329	=item EV_USE_POLL	2509	=item EV_USE_POLL
2330		2510
2331	If defined to be C<1>, libev will compile in support for the C<poll>(2)	2511	If defined to be C<1>, libev will compile in support for the C<poll>(2)
2332	backend. Otherwise it will be enabled on non-win32 platforms. It	2512	backend. Otherwise it will be enabled on non-win32 platforms. It
…		…
2369	be detected at runtime.	2549	be detected at runtime.
2370		2550
2371	=item EV_H	2551	=item EV_H
2372		2552
2373	The name of the F<ev.h> header file used to include it. The default if	2553	The name of the F<ev.h> header file used to include it. The default if
2374	undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This	2554	undefined is C<"ev.h"> in F<event.h> and F<ev.c>. This can be used to
2375	can be used to virtually rename the F<ev.h> header file in case of conflicts.	2555	virtually rename the F<ev.h> header file in case of conflicts.
2376		2556
2377	=item EV_CONFIG_H	2557	=item EV_CONFIG_H
2378		2558
2379	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override	2559	If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
2380	F<ev.c>'s idea of where to find the F<config.h> file, similarly to	2560	F<ev.c>'s idea of where to find the F<config.h> file, similarly to
2381	C<EV_H>, above.	2561	C<EV_H>, above.
2382		2562
2383	=item EV_EVENT_H	2563	=item EV_EVENT_H
2384		2564
2385	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea	2565	Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
2386	of how the F<event.h> header can be found.	2566	of how the F<event.h> header can be found, the dfeault is C<"event.h">.
2387		2567
2388	=item EV_PROTOTYPES	2568	=item EV_PROTOTYPES
2389		2569
2390	If defined to be C<0>, then F<ev.h> will not define any function	2570	If defined to be C<0>, then F<ev.h> will not define any function
2391	prototypes, but still define all the structs and other symbols. This is	2571	prototypes, but still define all the structs and other symbols. This is
…		…
2457	than enough. If you need to manage thousands of children you might want to	2637	than enough. If you need to manage thousands of children you might want to
2458	increase this value (I<must> be a power of two).	2638	increase this value (I<must> be a power of two).
2459		2639
2460	=item EV_INOTIFY_HASHSIZE	2640	=item EV_INOTIFY_HASHSIZE
2461		2641
2462	C<ev_staz> watchers use a small hash table to distribute workload by	2642	C<ev_stat> watchers use a small hash table to distribute workload by
2463	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),	2643	inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),
2464	usually more than enough. If you need to manage thousands of C<ev_stat>	2644	usually more than enough. If you need to manage thousands of C<ev_stat>
2465	watchers you might want to increase this value (I<must> be a power of	2645	watchers you might want to increase this value (I<must> be a power of
2466	two).	2646	two).
2467		2647
…		…
2563		2743
2564	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)	2744	=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
2565		2745
2566	This means that, when you have a watcher that triggers in one hour and	2746	This means that, when you have a watcher that triggers in one hour and
2567	there are 100 watchers that would trigger before that then inserting will	2747	there are 100 watchers that would trigger before that then inserting will
2568	have to skip those 100 watchers.	2748	have to skip roughly seven (C<ld 100>) of these watchers.
2569		2749
2570	=item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)	2750	=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)
2571		2751
2572	That means that for changing a timer costs less than removing/adding them	2752	That means that changing a timer costs less than removing/adding them
2573	as only the relative motion in the event queue has to be paid for.	2753	as only the relative motion in the event queue has to be paid for.
2574		2754
2575	=item Starting io/check/prepare/idle/signal/child watchers: O(1)	2755	=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2576		2756
2577	These just add the watcher into an array or at the head of a list.	2757	These just add the watcher into an array or at the head of a list.
		2758
2578	=item Stopping check/prepare/idle watchers: O(1)	2759	=item Stopping check/prepare/idle watchers: O(1)
2579		2760
2580	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))	2761	=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
2581		2762
2582	These watchers are stored in lists then need to be walked to find the	2763	These watchers are stored in lists then need to be walked to find the
2583	correct watcher to remove. The lists are usually short (you don't usually	2764	correct watcher to remove. The lists are usually short (you don't usually
2584	have many watchers waiting for the same fd or signal).	2765	have many watchers waiting for the same fd or signal).
2585		2766
2586	=item Finding the next timer per loop iteration: O(1)	2767	=item Finding the next timer in each loop iteration: O(1)
		2768
		2769	By virtue of using a binary heap, the next timer is always found at the
		2770	beginning of the storage array.
2587		2771
2588	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	2772	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2589		2773
2590	A change means an I/O watcher gets started or stopped, which requires	2774	A change means an I/O watcher gets started or stopped, which requires
2591	libev to recalculate its status (and possibly tell the kernel).	2775	libev to recalculate its status (and possibly tell the kernel, depending
		2776	on backend and wether C<ev_io_set> was used).
2592		2777
2593	=item Activating one watcher: O(1)	2778	=item Activating one watcher (putting it into the pending state): O(1)
2594		2779
2595	=item Priority handling: O(number_of_priorities)	2780	=item Priority handling: O(number_of_priorities)
2596		2781
2597	Priorities are implemented by allocating some space for each	2782	Priorities are implemented by allocating some space for each
2598	priority. When doing priority-based operations, libev usually has to	2783	priority. When doing priority-based operations, libev usually has to
2599	linearly search all the priorities.	2784	linearly search all the priorities, but starting/stopping and activating
		2785	watchers becomes O(1) w.r.t. prioritiy handling.
2600		2786
2601	=back	2787	=back
2602		2788
2603		2789
		2790	=head1 Win32 platform limitations and workarounds
		2791
		2792	Win32 doesn't support any of the standards (e.g. POSIX) that libev
		2793	requires, and its I/O model is fundamentally incompatible with the POSIX
		2794	model. Libev still offers limited functionality on this platform in
		2795	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
		2796	descriptors. This only applies when using Win32 natively, not when using
		2797	e.g. cygwin.
		2798
		2799	There is no supported compilation method available on windows except
		2800	embedding it into other applications.
		2801
		2802	Due to the many, low, and arbitrary limits on the win32 platform and the
		2803	abysmal performance of winsockets, using a large number of sockets is not
		2804	recommended (and not reasonable). If your program needs to use more than
		2805	a hundred or so sockets, then likely it needs to use a totally different
		2806	implementation for windows, as libev offers the POSIX model, which cannot
		2807	be implemented efficiently on windows (microsoft monopoly games).
		2808
		2809	=over 4
		2810
		2811	=item The winsocket select function
		2812
		2813	The winsocket C<select> function doesn't follow POSIX in that it requires
		2814	socket I<handles> and not socket I<file descriptors>. This makes select
		2815	very inefficient, and also requires a mapping from file descriptors
		2816	to socket handles. See the discussion of the C<EV_SELECT_USE_FD_SET>,
		2817	C<EV_SELECT_IS_WINSOCKET> and C<EV_FD_TO_WIN32_HANDLE> preprocessor
		2818	symbols for more info.
		2819
		2820	The configuration for a "naked" win32 using the microsoft runtime
		2821	libraries and raw winsocket select is:
		2822
		2823	#define EV_USE_SELECT 1
		2824	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
		2825
		2826	Note that winsockets handling of fd sets is O(n), so you can easily get a
		2827	complexity in the O(n²) range when using win32.
		2828
		2829	=item Limited number of file descriptors
		2830
		2831	Windows has numerous arbitrary (and low) limits on things. Early versions
		2832	of winsocket's select only supported waiting for a max. of C<64> handles
		2833	(probably owning to the fact that all windows kernels can only wait for
		2834	C<64> things at the same time internally; microsoft recommends spawning a
		2835	chain of threads and wait for 63 handles and the previous thread in each).
		2836
		2837	Newer versions support more handles, but you need to define C<FD_SETSIZE>
		2838	to some high number (e.g. C<2048>) before compiling the winsocket select
		2839	call (which might be in libev or elsewhere, for example, perl does its own
		2840	select emulation on windows).
		2841
		2842	Another limit is the number of file descriptors in the microsoft runtime
		2843	libraries, which by default is C<64> (there must be a hidden I<64> fetish
		2844	or something like this inside microsoft). You can increase this by calling
		2845	C<_setmaxstdio>, which can increase this limit to C<2048> (another
		2846	arbitrary limit), but is broken in many versions of the microsoft runtime
		2847	libraries.
		2848
		2849	This might get you to about C<512> or C<2048> sockets (depending on
		2850	windows version and/or the phase of the moon). To get more, you need to
		2851	wrap all I/O functions and provide your own fd management, but the cost of
		2852	calling select (O(n²)) will likely make this unworkable.
		2853
		2854	=back
		2855
		2856
2604	=head1 AUTHOR	2857	=head1 AUTHOR
2605		2858
2606	Marc Lehmann <libev@schmorp.de>.	2859	Marc Lehmann <libev@schmorp.de>.
2607		2860

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Comparing libev/ev.pod (file contents): Revision 1.95 by root, Fri Dec 21 05:10:01 2007 UTC vs. Revision 1.114 by root, Mon Dec 31 01:31:30 2007 UTC

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Comparing libev/ev.pod (file contents):
Revision 1.95 by root, Fri Dec 21 05:10:01 2007 UTC vs.
Revision 1.114 by root, Mon Dec 31 01:31:30 2007 UTC