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Revision 1.160 by root, Thu May 22 03:06:58 2008 UTC vs.
Revision 1.164 by root, Sat May 31 23:22:23 2008 UTC

…		…
2		2
3	libev - a high performance full-featured event loop written in C	3	libev - a high performance full-featured event loop written in C
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	#include <ev.h>	7	#include <ev.h>
8		8
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	// every watcher type has its own typedef'd struct	14	// every watcher type has its own typedef'd struct
15	// with the name ev_<type>	15	// with the name ev_<type>
16	ev_io stdin_watcher;	16	ev_io stdin_watcher;
17	ev_timer timeout_watcher;	17	ev_timer timeout_watcher;
18		18
19	// all watcher callbacks have a similar signature	19	// all watcher callbacks have a similar signature
20	// this callback is called when data is readable on stdin	20	// this callback is called when data is readable on stdin
21	static void	21	static void
22	stdin_cb (EV_P_ struct ev_io *w, int revents)	22	stdin_cb (EV_P_ struct ev_io *w, int revents)
23	{	23	{
24	puts ("stdin ready");	24	puts ("stdin ready");
25	// for one-shot events, one must manually stop the watcher	25	// for one-shot events, one must manually stop the watcher
26	// with its corresponding stop function.	26	// with its corresponding stop function.
27	ev_io_stop (EV_A_ w);	27	ev_io_stop (EV_A_ w);
28		28
29	// this causes all nested ev_loop's to stop iterating	29	// this causes all nested ev_loop's to stop iterating
30	ev_unloop (EV_A_ EVUNLOOP_ALL);	30	ev_unloop (EV_A_ EVUNLOOP_ALL);
31	}	31	}
32		32
33	// another callback, this time for a time-out	33	// another callback, this time for a time-out
34	static void	34	static void
35	timeout_cb (EV_P_ struct ev_timer *w, int revents)	35	timeout_cb (EV_P_ struct ev_timer *w, int revents)
36	{	36	{
37	puts ("timeout");	37	puts ("timeout");
38	// this causes the innermost ev_loop to stop iterating	38	// this causes the innermost ev_loop to stop iterating
39	ev_unloop (EV_A_ EVUNLOOP_ONE);	39	ev_unloop (EV_A_ EVUNLOOP_ONE);
40	}	40	}
41		41
42	int	42	int
43	main (void)	43	main (void)
44	{	44	{
45	// use the default event loop unless you have special needs	45	// use the default event loop unless you have special needs
46	struct ev_loop *loop = ev_default_loop (0);	46	struct ev_loop *loop = ev_default_loop (0);
47		47
48	// initialise an io watcher, then start it	48	// initialise an io watcher, then start it
49	// this one will watch for stdin to become readable	49	// this one will watch for stdin to become readable
50	ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);	50	ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
51	ev_io_start (loop, &stdin_watcher);	51	ev_io_start (loop, &stdin_watcher);
52		52
53	// initialise a timer watcher, then start it	53	// initialise a timer watcher, then start it
54	// simple non-repeating 5.5 second timeout	54	// simple non-repeating 5.5 second timeout
55	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);	55	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
56	ev_timer_start (loop, &timeout_watcher);	56	ev_timer_start (loop, &timeout_watcher);
57		57
58	// now wait for events to arrive	58	// now wait for events to arrive
59	ev_loop (loop, 0);	59	ev_loop (loop, 0);
60		60
61	// unloop was called, so exit	61	// unloop was called, so exit
62	return 0;	62	return 0;
63	}	63	}
64		64
65	=head1 DESCRIPTION	65	=head1 DESCRIPTION
66		66
67	The newest version of this document is also available as an html-formatted	67	The newest version of this document is also available as an html-formatted
68	web page you might find easier to navigate when reading it for the first	68	web page you might find easier to navigate when reading it for the first
…		…
113	Libev represents time as a single floating point number, representing the	113	Libev represents time as a single floating point number, representing the
114	(fractional) number of seconds since the (POSIX) epoch (somewhere near	114	(fractional) number of seconds since the (POSIX) epoch (somewhere near
115	the beginning of 1970, details are complicated, don't ask). This type is	115	the beginning of 1970, details are complicated, don't ask). This type is
116	called C<ev_tstamp>, which is what you should use too. It usually aliases	116	called C<ev_tstamp>, which is what you should use too. It usually aliases
117	to the C<double> type in C, and when you need to do any calculations on	117	to the C<double> type in C, and when you need to do any calculations on
118	it, you should treat it as some floatingpoint value. Unlike the name	118	it, you should treat it as some floating point value. Unlike the name
119	component C<stamp> might indicate, it is also used for time differences	119	component C<stamp> might indicate, it is also used for time differences
120	throughout libev.	120	throughout libev.
121		121
122	=head1 ERROR HANDLING	122	=head1 ERROR HANDLING
123		123
124	Libev knows three classes of errors: operating system errors, usage errors	124	Libev knows three classes of errors: operating system errors, usage errors
125	and internal errors (bugs).	125	and internal errors (bugs).
126		126
127	When libev catches an operating system error it cannot handle (for example	127	When libev catches an operating system error it cannot handle (for example
128	a syscall indicating a condition libev cannot fix), it calls the callback	128	a system call indicating a condition libev cannot fix), it calls the callback
129	set via C<ev_set_syserr_cb>, which is supposed to fix the problem or	129	set via C<ev_set_syserr_cb>, which is supposed to fix the problem or
130	abort. The default is to print a diagnostic message and to call C<abort	130	abort. The default is to print a diagnostic message and to call C<abort
131	()>.	131	()>.
132		132
133	When libev detects a usage error such as a negative timer interval, then	133	When libev detects a usage error such as a negative timer interval, then
…		…
155		155
156	=item ev_sleep (ev_tstamp interval)	156	=item ev_sleep (ev_tstamp interval)
157		157
158	Sleep for the given interval: The current thread will be blocked until	158	Sleep for the given interval: The current thread will be blocked until
159	either it is interrupted or the given time interval has passed. Basically	159	either it is interrupted or the given time interval has passed. Basically
160	this is a subsecond-resolution C<sleep ()>.	160	this is a sub-second-resolution C<sleep ()>.
161		161
162	=item int ev_version_major ()	162	=item int ev_version_major ()
163		163
164	=item int ev_version_minor ()	164	=item int ev_version_minor ()
165		165
…		…
178	not a problem.	178	not a problem.
179		179
180	Example: Make sure we haven't accidentally been linked against the wrong	180	Example: Make sure we haven't accidentally been linked against the wrong
181	version.	181	version.
182		182
183	assert (("libev version mismatch",	183	assert (("libev version mismatch",
184	ev_version_major () == EV_VERSION_MAJOR	184	ev_version_major () == EV_VERSION_MAJOR
185	&& ev_version_minor () >= EV_VERSION_MINOR));	185	&& ev_version_minor () >= EV_VERSION_MINOR));
186		186
187	=item unsigned int ev_supported_backends ()	187	=item unsigned int ev_supported_backends ()
188		188
189	Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*>	189	Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*>
190	value) compiled into this binary of libev (independent of their	190	value) compiled into this binary of libev (independent of their
…		…
192	a description of the set values.	192	a description of the set values.
193		193
194	Example: make sure we have the epoll method, because yeah this is cool and	194	Example: make sure we have the epoll method, because yeah this is cool and
195	a must have and can we have a torrent of it please!!!11	195	a must have and can we have a torrent of it please!!!11
196		196
197	assert (("sorry, no epoll, no sex",	197	assert (("sorry, no epoll, no sex",
198	ev_supported_backends () & EVBACKEND_EPOLL));	198	ev_supported_backends () & EVBACKEND_EPOLL));
199		199
200	=item unsigned int ev_recommended_backends ()	200	=item unsigned int ev_recommended_backends ()
201		201
202	Return the set of all backends compiled into this binary of libev and also	202	Return the set of all backends compiled into this binary of libev and also
203	recommended for this platform. This set is often smaller than the one	203	recommended for this platform. This set is often smaller than the one
204	returned by C<ev_supported_backends>, as for example kqueue is broken on	204	returned by C<ev_supported_backends>, as for example kqueue is broken on
205	most BSDs and will not be autodetected unless you explicitly request it	205	most BSDs and will not be auto-detected unless you explicitly request it
206	(assuming you know what you are doing). This is the set of backends that	206	(assuming you know what you are doing). This is the set of backends that
207	libev will probe for if you specify no backends explicitly.	207	libev will probe for if you specify no backends explicitly.
208		208
209	=item unsigned int ev_embeddable_backends ()	209	=item unsigned int ev_embeddable_backends ()
210		210
…		…
252	...	252	...
253	ev_set_allocator (persistent_realloc);	253	ev_set_allocator (persistent_realloc);
254		254
255	=item ev_set_syserr_cb (void (*cb)(const char *msg));	255	=item ev_set_syserr_cb (void (*cb)(const char *msg));
256		256
257	Set the callback function to call on a retryable syscall error (such	257	Set the callback function to call on a retryable system call error (such
258	as failed select, poll, epoll_wait). The message is a printable string	258	as failed select, poll, epoll_wait). The message is a printable string
259	indicating the system call or subsystem causing the problem. If this	259	indicating the system call or subsystem causing the problem. If this
260	callback is set, then libev will expect it to remedy the sitution, no	260	callback is set, then libev will expect it to remedy the situation, no
261	matter what, when it returns. That is, libev will generally retry the	261	matter what, when it returns. That is, libev will generally retry the
262	requested operation, or, if the condition doesn't go away, do bad stuff	262	requested operation, or, if the condition doesn't go away, do bad stuff
263	(such as abort).	263	(such as abort).
264		264
265	Example: This is basically the same thing that libev does internally, too.	265	Example: This is basically the same thing that libev does internally, too.
…		…
298	from multiple threads, you have to lock (note also that this is unlikely,	298	from multiple threads, you have to lock (note also that this is unlikely,
299	as loops cannot bes hared easily between threads anyway).	299	as loops cannot bes hared easily between threads anyway).
300		300
301	The default loop is the only loop that can handle C<ev_signal> and	301	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	302	C<ev_child> watchers, and to do this, it always registers a handler
303	for C<SIGCHLD>. If this is a problem for your app you can either	303	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	304	create a dynamic loop with C<ev_loop_new> that doesn't do that, or you
305	can simply overwrite the C<SIGCHLD> signal handler I<after> calling	305	can simply overwrite the C<SIGCHLD> signal handler I<after> calling
306	C<ev_default_init>.	306	C<ev_default_init>.
307		307
308	The flags argument can be used to specify special behaviour or specific	308	The flags argument can be used to specify special behaviour or specific
…		…
317	The default flags value. Use this if you have no clue (it's the right	317	The default flags value. Use this if you have no clue (it's the right
318	thing, believe me).	318	thing, believe me).
319		319
320	=item C<EVFLAG_NOENV>	320	=item C<EVFLAG_NOENV>
321		321
322	If this flag bit is ored into the flag value (or the program runs setuid	322	If this flag bit is or'ed into the flag value (or the program runs setuid
323	or setgid) then libev will I<not> look at the environment variable	323	or setgid) then libev will I<not> look at the environment variable
324	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will	324	C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
325	override the flags completely if it is found in the environment. This is	325	override the flags completely if it is found in the environment. This is
326	useful to try out specific backends to test their performance, or to work	326	useful to try out specific backends to test their performance, or to work
327	around bugs.	327	around bugs.
…		…
334		334
335	This works by calling C<getpid ()> on every iteration of the loop,	335	This works by calling C<getpid ()> on every iteration of the loop,
336	and thus this might slow down your event loop if you do a lot of loop	336	and thus this might slow down your event loop if you do a lot of loop
337	iterations and little real work, but is usually not noticeable (on my	337	iterations and little real work, but is usually not noticeable (on my
338	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence	338	GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
339	without a syscall and thus I<very> fast, but my GNU/Linux system also has	339	without a system call and thus I<very> fast, but my GNU/Linux system also has
340	C<pthread_atfork> which is even faster).	340	C<pthread_atfork> which is even faster).
341		341
342	The big advantage of this flag is that you can forget about fork (and	342	The big advantage of this flag is that you can forget about fork (and
343	forget about forgetting to tell libev about forking) when you use this	343	forget about forgetting to tell libev about forking) when you use this
344	flag.	344	flag.
345		345
346	This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS>	346	This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS>
347	environment variable.	347	environment variable.
348		348
349	=item C<EVBACKEND_SELECT> (value 1, portable select backend)	349	=item C<EVBACKEND_SELECT> (value 1, portable select backend)
350		350
351	This is your standard select(2) backend. Not I<completely> standard, as	351	This is your standard select(2) backend. Not I<completely> standard, as
…		…
353	but if that fails, expect a fairly low limit on the number of fds when	353	but if that fails, expect a fairly low limit on the number of fds when
354	using this backend. It doesn't scale too well (O(highest_fd)), but its	354	using this backend. It doesn't scale too well (O(highest_fd)), but its
355	usually the fastest backend for a low number of (low-numbered :) fds.	355	usually the fastest backend for a low number of (low-numbered :) fds.
356		356
357	To get good performance out of this backend you need a high amount of	357	To get good performance out of this backend you need a high amount of
358	parallelity (most of the file descriptors should be busy). If you are	358	parallelism (most of the file descriptors should be busy). If you are
359	writing a server, you should C<accept ()> in a loop to accept as many	359	writing a server, you should C<accept ()> in a loop to accept as many
360	connections as possible during one iteration. You might also want to have	360	connections as possible during one iteration. You might also want to have
361	a look at C<ev_set_io_collect_interval ()> to increase the amount of	361	a look at C<ev_set_io_collect_interval ()> to increase the amount of
362	readiness notifications you get per iteration.	362	readiness notifications you get per iteration.
363		363
…		…
375	For few fds, this backend is a bit little slower than poll and select,	375	For few fds, this backend is a bit little slower than poll and select,
376	but it scales phenomenally better. While poll and select usually scale	376	but it scales phenomenally better. While poll and select usually scale
377	like O(total_fds) where n is the total number of fds (or the highest fd),	377	like O(total_fds) where n is the total number of fds (or the highest fd),
378	epoll scales either O(1) or O(active_fds). The epoll design has a number	378	epoll scales either O(1) or O(active_fds). The epoll design has a number
379	of shortcomings, such as silently dropping events in some hard-to-detect	379	of shortcomings, such as silently dropping events in some hard-to-detect
380	cases and requiring a syscall per fd change, no fork support and bad	380	cases and requiring a system call per fd change, no fork support and bad
381	support for dup.	381	support for dup.
382		382
383	While stopping, setting and starting an I/O watcher in the same iteration	383	While stopping, setting and starting an I/O watcher in the same iteration
384	will result in some caching, there is still a syscall per such incident	384	will result in some caching, there is still a system call per such incident
385	(because the fd could point to a different file description now), so its	385	(because the fd could point to a different file description now), so its
386	best to avoid that. Also, C<dup ()>'ed file descriptors might not work	386	best to avoid that. Also, C<dup ()>'ed file descriptors might not work
387	very well if you register events for both fds.	387	very well if you register events for both fds.
388		388
389	Please note that epoll sometimes generates spurious notifications, so you	389	Please note that epoll sometimes generates spurious notifications, so you
…		…
392		392
393	Best performance from this backend is achieved by not unregistering all	393	Best performance from this backend is achieved by not unregistering all
394	watchers for a file descriptor until it has been closed, if possible, i.e.	394	watchers for a file descriptor until it has been closed, if possible, i.e.
395	keep at least one watcher active per fd at all times.	395	keep at least one watcher active per fd at all times.
396		396
397	While nominally embeddeble in other event loops, this feature is broken in	397	While nominally embeddable in other event loops, this feature is broken in
398	all kernel versions tested so far.	398	all kernel versions tested so far.
399		399
400	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)	400	=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
401		401
402	Kqueue deserves special mention, as at the time of this writing, it	402	Kqueue deserves special mention, as at the time of this writing, it
403	was broken on all BSDs except NetBSD (usually it doesn't work reliably	403	was broken on all BSDs except NetBSD (usually it doesn't work reliably
404	with anything but sockets and pipes, except on Darwin, where of course	404	with anything but sockets and pipes, except on Darwin, where of course
405	it's completely useless). For this reason it's not being "autodetected"	405	it's completely useless). For this reason it's not being "auto-detected"
406	unless you explicitly specify it explicitly in the flags (i.e. using	406	unless you explicitly specify it explicitly in the flags (i.e. using
407	C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough)	407	C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough)
408	system like NetBSD.	408	system like NetBSD.
409		409
410	You still can embed kqueue into a normal poll or select backend and use it	410	You still can embed kqueue into a normal poll or select backend and use it
…		…
412	the target platform). See C<ev_embed> watchers for more info.	412	the target platform). See C<ev_embed> watchers for more info.
413		413
414	It scales in the same way as the epoll backend, but the interface to the	414	It scales in the same way as the epoll backend, but the interface to the
415	kernel is more efficient (which says nothing about its actual speed, of	415	kernel is more efficient (which says nothing about its actual speed, of
416	course). While stopping, setting and starting an I/O watcher does never	416	course). While stopping, setting and starting an I/O watcher does never
417	cause an extra syscall as with C<EVBACKEND_EPOLL>, it still adds up to	417	cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to
418	two event changes per incident, support for C<fork ()> is very bad and it	418	two event changes per incident, support for C<fork ()> is very bad and it
419	drops fds silently in similarly hard-to-detect cases.	419	drops fds silently in similarly hard-to-detect cases.
420		420
421	This backend usually performs well under most conditions.	421	This backend usually performs well under most conditions.
422		422
…		…
437	=item C<EVBACKEND_PORT> (value 32, Solaris 10)	437	=item C<EVBACKEND_PORT> (value 32, Solaris 10)
438		438
439	This uses the Solaris 10 event port mechanism. As with everything on Solaris,	439	This uses the Solaris 10 event port mechanism. As with everything on Solaris,
440	it's really slow, but it still scales very well (O(active_fds)).	440	it's really slow, but it still scales very well (O(active_fds)).
441		441
442	Please note that solaris event ports can deliver a lot of spurious	442	Please note that Solaris event ports can deliver a lot of spurious
443	notifications, so you need to use non-blocking I/O or other means to avoid	443	notifications, so you need to use non-blocking I/O or other means to avoid
444	blocking when no data (or space) is available.	444	blocking when no data (or space) is available.
445		445
446	While this backend scales well, it requires one system call per active	446	While this backend scales well, it requires one system call per active
447	file descriptor per loop iteration. For small and medium numbers of file	447	file descriptor per loop iteration. For small and medium numbers of file
…		…
460		460
461	It is definitely not recommended to use this flag.	461	It is definitely not recommended to use this flag.
462		462
463	=back	463	=back
464		464
465	If one or more of these are ored into the flags value, then only these	465	If one or more of these are or'ed into the flags value, then only these
466	backends will be tried (in the reverse order as listed here). If none are	466	backends will be tried (in the reverse order as listed here). If none are
467	specified, all backends in C<ev_recommended_backends ()> will be tried.	467	specified, all backends in C<ev_recommended_backends ()> will be tried.
468		468
469	The most typical usage is like this:	469	The most typical usage is like this:
470		470
471	if (!ev_default_loop (0))	471	if (!ev_default_loop (0))
472	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");	472	fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
473		473
474	Restrict libev to the select and poll backends, and do not allow	474	Restrict libev to the select and poll backends, and do not allow
475	environment settings to be taken into account:	475	environment settings to be taken into account:
476		476
477	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);	477	ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
478		478
479	Use whatever libev has to offer, but make sure that kqueue is used if	479	Use whatever libev has to offer, but make sure that kqueue is used if
480	available (warning, breaks stuff, best use only with your own private	480	available (warning, breaks stuff, best use only with your own private
481	event loop and only if you know the OS supports your types of fds):	481	event loop and only if you know the OS supports your types of fds):
482		482
483	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);	483	ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
484		484
485	=item struct ev_loop *ev_loop_new (unsigned int flags)	485	=item struct ev_loop *ev_loop_new (unsigned int flags)
486		486
487	Similar to C<ev_default_loop>, but always creates a new event loop that is	487	Similar to C<ev_default_loop>, but always creates a new event loop that is
488	always distinct from the default loop. Unlike the default loop, it cannot	488	always distinct from the default loop. Unlike the default loop, it cannot
…		…
493	libev with threads is indeed to create one loop per thread, and using the	493	libev with threads is indeed to create one loop per thread, and using the
494	default loop in the "main" or "initial" thread.	494	default loop in the "main" or "initial" thread.
495		495
496	Example: Try to create a event loop that uses epoll and nothing else.	496	Example: Try to create a event loop that uses epoll and nothing else.
497		497
498	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);	498	struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
499	if (!epoller)	499	if (!epoller)
500	fatal ("no epoll found here, maybe it hides under your chair");	500	fatal ("no epoll found here, maybe it hides under your chair");
501		501
502	=item ev_default_destroy ()	502	=item ev_default_destroy ()
503		503
504	Destroys the default loop again (frees all memory and kernel state	504	Destroys the default loop again (frees all memory and kernel state
505	etc.). None of the active event watchers will be stopped in the normal	505	etc.). None of the active event watchers will be stopped in the normal
506	sense, so e.g. C<ev_is_active> might still return true. It is your	506	sense, so e.g. C<ev_is_active> might still return true. It is your
507	responsibility to either stop all watchers cleanly yoursef I<before>	507	responsibility to either stop all watchers cleanly yourself I<before>
508	calling this function, or cope with the fact afterwards (which is usually	508	calling this function, or cope with the fact afterwards (which is usually
509	the easiest thing, you can just ignore the watchers and/or C<free ()> them	509	the easiest thing, you can just ignore the watchers and/or C<free ()> them
510	for example).	510	for example).
511		511
512	Note that certain global state, such as signal state, will not be freed by	512	Note that certain global state, such as signal state, will not be freed by
…		…
593	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle	593	A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle
594	those events and any outstanding ones, but will not block your process in	594	those events and any outstanding ones, but will not block your process in
595	case there are no events and will return after one iteration of the loop.	595	case there are no events and will return after one iteration of the loop.
596		596
597	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if	597	A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if
598	neccessary) and will handle those and any outstanding ones. It will block	598	necessary) and will handle those and any outstanding ones. It will block
599	your process until at least one new event arrives, and will return after	599	your process until at least one new event arrives, and will return after
600	one iteration of the loop. This is useful if you are waiting for some	600	one iteration of the loop. This is useful if you are waiting for some
601	external event in conjunction with something not expressible using other	601	external event in conjunction with something not expressible using other
602	libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is	602	libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is
603	usually a better approach for this kind of thing.	603	usually a better approach for this kind of thing.
…		…
664	respectively).	664	respectively).
665		665
666	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	666	Example: Create a signal watcher, but keep it from keeping C<ev_loop>
667	running when nothing else is active.	667	running when nothing else is active.
668		668
669	struct ev_signal exitsig;	669	struct ev_signal exitsig;
670	ev_signal_init (&exitsig, sig_cb, SIGINT);	670	ev_signal_init (&exitsig, sig_cb, SIGINT);
671	ev_signal_start (loop, &exitsig);	671	ev_signal_start (loop, &exitsig);
672	evf_unref (loop);	672	evf_unref (loop);
673		673
674	Example: For some weird reason, unregister the above signal handler again.	674	Example: For some weird reason, unregister the above signal handler again.
675		675
676	ev_ref (loop);	676	ev_ref (loop);
677	ev_signal_stop (loop, &exitsig);	677	ev_signal_stop (loop, &exitsig);
678		678
679	=item ev_set_io_collect_interval (loop, ev_tstamp interval)	679	=item ev_set_io_collect_interval (loop, ev_tstamp interval)
680		680
681	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)	681	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
682		682
…		…
704	to spend more time collecting timeouts, at the expense of increased	704	to spend more time collecting timeouts, at the expense of increased
705	latency (the watcher callback will be called later). C<ev_io> watchers	705	latency (the watcher callback will be called later). C<ev_io> watchers
706	will not be affected. Setting this to a non-null value will not introduce	706	will not be affected. Setting this to a non-null value will not introduce
707	any overhead in libev.	707	any overhead in libev.
708		708
709	Many (busy) programs can usually benefit by setting the io collect	709	Many (busy) programs can usually benefit by setting the I/O collect
710	interval to a value near C<0.1> or so, which is often enough for	710	interval to a value near C<0.1> or so, which is often enough for
711	interactive servers (of course not for games), likewise for timeouts. It	711	interactive servers (of course not for games), likewise for timeouts. It
712	usually doesn't make much sense to set it to a lower value than C<0.01>,	712	usually doesn't make much sense to set it to a lower value than C<0.01>,
713	as this approsaches the timing granularity of most systems.	713	as this approaches the timing granularity of most systems.
714		714
715	=item ev_loop_verify (loop)	715	=item ev_loop_verify (loop)
716		716
717	This function only does something when C<EV_VERIFY> support has been	717	This function only does something when C<EV_VERIFY> support has been
718	compiled in. It tries to go through all internal structures and checks	718	compiled in. It tries to go through all internal structures and checks
…		…
730		730
731	A watcher is a structure that you create and register to record your	731	A watcher is a structure that you create and register to record your
732	interest in some event. For instance, if you want to wait for STDIN to	732	interest in some event. For instance, if you want to wait for STDIN to
733	become readable, you would create an C<ev_io> watcher for that:	733	become readable, you would create an C<ev_io> watcher for that:
734		734
735	static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents)	735	static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents)
736	{	736	{
737	ev_io_stop (w);	737	ev_io_stop (w);
738	ev_unloop (loop, EVUNLOOP_ALL);	738	ev_unloop (loop, EVUNLOOP_ALL);
739	}	739	}
740		740
741	struct ev_loop *loop = ev_default_loop (0);	741	struct ev_loop *loop = ev_default_loop (0);
742	struct ev_io stdin_watcher;	742	struct ev_io stdin_watcher;
743	ev_init (&stdin_watcher, my_cb);	743	ev_init (&stdin_watcher, my_cb);
744	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	744	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
745	ev_io_start (loop, &stdin_watcher);	745	ev_io_start (loop, &stdin_watcher);
746	ev_loop (loop, 0);	746	ev_loop (loop, 0);
747		747
748	As you can see, you are responsible for allocating the memory for your	748	As you can see, you are responsible for allocating the memory for your
749	watcher structures (and it is usually a bad idea to do this on the stack,	749	watcher structures (and it is usually a bad idea to do this on the stack,
750	although this can sometimes be quite valid).	750	although this can sometimes be quite valid).
751		751
752	Each watcher structure must be initialised by a call to C<ev_init	752	Each watcher structure must be initialised by a call to C<ev_init
753	(watcher *, callback)>, which expects a callback to be provided. This	753	(watcher *, callback)>, which expects a callback to be provided. This
754	callback gets invoked each time the event occurs (or, in the case of io	754	callback gets invoked each time the event occurs (or, in the case of I/O
755	watchers, each time the event loop detects that the file descriptor given	755	watchers, each time the event loop detects that the file descriptor given
756	is readable and/or writable).	756	is readable and/or writable).
757		757
758	Each watcher type has its own C<< ev_<type>_set (watcher *, ...) >> macro	758	Each watcher type has its own C<< ev_<type>_set (watcher *, ...) >> macro
759	with arguments specific to this watcher type. There is also a macro	759	with arguments specific to this watcher type. There is also a macro
…		…
835		835
836	The given async watcher has been asynchronously notified (see C<ev_async>).	836	The given async watcher has been asynchronously notified (see C<ev_async>).
837		837
838	=item C<EV_ERROR>	838	=item C<EV_ERROR>
839		839
840	An unspecified error has occured, the watcher has been stopped. This might	840	An unspecified error has occurred, the watcher has been stopped. This might
841	happen because the watcher could not be properly started because libev	841	happen because the watcher could not be properly started because libev
842	ran out of memory, a file descriptor was found to be closed or any other	842	ran out of memory, a file descriptor was found to be closed or any other
843	problem. You best act on it by reporting the problem and somehow coping	843	problem. You best act on it by reporting the problem and somehow coping
844	with the watcher being stopped.	844	with the watcher being stopped.
845		845
846	Libev will usually signal a few "dummy" events together with an error,	846	Libev will usually signal a few "dummy" events together with an error,
847	for example it might indicate that a fd is readable or writable, and if	847	for example it might indicate that a fd is readable or writable, and if
848	your callbacks is well-written it can just attempt the operation and cope	848	your callbacks is well-written it can just attempt the operation and cope
849	with the error from read() or write(). This will not work in multithreaded	849	with the error from read() or write(). This will not work in multi-threaded
850	programs, though, so beware.	850	programs, though, so beware.
851		851
852	=back	852	=back
853		853
854	=head2 GENERIC WATCHER FUNCTIONS	854	=head2 GENERIC WATCHER FUNCTIONS
…		…
884	Although some watcher types do not have type-specific arguments	884	Although some watcher types do not have type-specific arguments
885	(e.g. C<ev_prepare>) you still need to call its C<set> macro.	885	(e.g. C<ev_prepare>) you still need to call its C<set> macro.
886		886
887	=item C<ev_TYPE_init> (ev_TYPE *watcher, callback, [args])	887	=item C<ev_TYPE_init> (ev_TYPE *watcher, callback, [args])
888		888
889	This convinience macro rolls both C<ev_init> and C<ev_TYPE_set> macro	889	This convenience macro rolls both C<ev_init> and C<ev_TYPE_set> macro
890	calls into a single call. This is the most convinient method to initialise	890	calls into a single call. This is the most convenient method to initialise
891	a watcher. The same limitations apply, of course.	891	a watcher. The same limitations apply, of course.
892		892
893	=item C<ev_TYPE_start> (loop *, ev_TYPE *watcher)	893	=item C<ev_TYPE_start> (loop *, ev_TYPE *watcher)
894		894
895	Starts (activates) the given watcher. Only active watchers will receive	895	Starts (activates) the given watcher. Only active watchers will receive
…		…
978	to associate arbitrary data with your watcher. If you need more data and	978	to associate arbitrary data with your watcher. If you need more data and
979	don't want to allocate memory and store a pointer to it in that data	979	don't want to allocate memory and store a pointer to it in that data
980	member, you can also "subclass" the watcher type and provide your own	980	member, you can also "subclass" the watcher type and provide your own
981	data:	981	data:
982		982
983	struct my_io	983	struct my_io
984	{	984	{
985	struct ev_io io;	985	struct ev_io io;
986	int otherfd;	986	int otherfd;
987	void *somedata;	987	void *somedata;
988	struct whatever *mostinteresting;	988	struct whatever *mostinteresting;
989	}	989	}
990		990
991	And since your callback will be called with a pointer to the watcher, you	991	And since your callback will be called with a pointer to the watcher, you
992	can cast it back to your own type:	992	can cast it back to your own type:
993		993
994	static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents)	994	static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents)
995	{	995	{
996	struct my_io *w = (struct my_io *)w_;	996	struct my_io *w = (struct my_io *)w_;
997	...	997	...
998	}	998	}
999		999
1000	More interesting and less C-conformant ways of casting your callback type	1000	More interesting and less C-conformant ways of casting your callback type
1001	instead have been omitted.	1001	instead have been omitted.
1002		1002
1003	Another common scenario is having some data structure with multiple	1003	Another common scenario is having some data structure with multiple
1004	watchers:	1004	watchers:
1005		1005
1006	struct my_biggy	1006	struct my_biggy
1007	{	1007	{
1008	int some_data;	1008	int some_data;
1009	ev_timer t1;	1009	ev_timer t1;
1010	ev_timer t2;	1010	ev_timer t2;
1011	}	1011	}
1012		1012
1013	In this case getting the pointer to C<my_biggy> is a bit more complicated,	1013	In this case getting the pointer to C<my_biggy> is a bit more complicated,
1014	you need to use C<offsetof>:	1014	you need to use C<offsetof>:
1015		1015
1016	#include <stddef.h>	1016	#include <stddef.h>
1017		1017
1018	static void	1018	static void
1019	t1_cb (EV_P_ struct ev_timer *w, int revents)	1019	t1_cb (EV_P_ struct ev_timer *w, int revents)
1020	{	1020	{
1021	struct my_biggy big = (struct my_biggy *	1021	struct my_biggy big = (struct my_biggy *
1022	(((char *)w) - offsetof (struct my_biggy, t1));	1022	(((char *)w) - offsetof (struct my_biggy, t1));
1023	}	1023	}
1024		1024
1025	static void	1025	static void
1026	t2_cb (EV_P_ struct ev_timer *w, int revents)	1026	t2_cb (EV_P_ struct ev_timer *w, int revents)
1027	{	1027	{
1028	struct my_biggy big = (struct my_biggy *	1028	struct my_biggy big = (struct my_biggy *
1029	(((char *)w) - offsetof (struct my_biggy, t2));	1029	(((char *)w) - offsetof (struct my_biggy, t2));
1030	}	1030	}
1031		1031
1032		1032
1033	=head1 WATCHER TYPES	1033	=head1 WATCHER TYPES
1034		1034
1035	This section describes each watcher in detail, but will not repeat	1035	This section describes each watcher in detail, but will not repeat
…		…
1067		1067
1068	Another thing you have to watch out for is that it is quite easy to	1068	Another thing you have to watch out for is that it is quite easy to
1069	receive "spurious" readiness notifications, that is your callback might	1069	receive "spurious" readiness notifications, that is your callback might
1070	be called with C<EV_READ> but a subsequent C<read>(2) will actually block	1070	be called with C<EV_READ> but a subsequent C<read>(2) will actually block
1071	because there is no data. Not only are some backends known to create a	1071	because there is no data. Not only are some backends known to create a
1072	lot of those (for example solaris ports), it is very easy to get into	1072	lot of those (for example Solaris ports), it is very easy to get into
1073	this situation even with a relatively standard program structure. Thus	1073	this situation even with a relatively standard program structure. Thus
1074	it is best to always use non-blocking I/O: An extra C<read>(2) returning	1074	it is best to always use non-blocking I/O: An extra C<read>(2) returning
1075	C<EAGAIN> is far preferable to a program hanging until some data arrives.	1075	C<EAGAIN> is far preferable to a program hanging until some data arrives.
1076		1076
1077	If you cannot run the fd in non-blocking mode (for example you should not	1077	If you cannot run the fd in non-blocking mode (for example you should not
1078	play around with an Xlib connection), then you have to seperately re-test	1078	play around with an Xlib connection), then you have to separately re-test
1079	whether a file descriptor is really ready with a known-to-be good interface	1079	whether a file descriptor is really ready with a known-to-be good interface
1080	such as poll (fortunately in our Xlib example, Xlib already does this on	1080	such as poll (fortunately in our Xlib example, Xlib already does this on
1081	its own, so its quite safe to use).	1081	its own, so its quite safe to use).
1082		1082
1083	=head3 The special problem of disappearing file descriptors	1083	=head3 The special problem of disappearing file descriptors
…		…
1143	=item ev_io_init (ev_io *, callback, int fd, int events)	1143	=item ev_io_init (ev_io *, callback, int fd, int events)
1144		1144
1145	=item ev_io_set (ev_io *, int fd, int events)	1145	=item ev_io_set (ev_io *, int fd, int events)
1146		1146
1147	Configures an C<ev_io> watcher. The C<fd> is the file descriptor to	1147	Configures an C<ev_io> watcher. The C<fd> is the file descriptor to
1148	rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or	1148	receive events for and events is either C<EV_READ>, C<EV_WRITE> or
1149	C<EV_READ | EV_WRITE> to receive the given events.	1149	C<EV_READ | EV_WRITE> to receive the given events.
1150		1150
1151	=item int fd [read-only]	1151	=item int fd [read-only]
1152		1152
1153	The file descriptor being watched.	1153	The file descriptor being watched.
…		…
1162		1162
1163	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well	1163	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
1164	readable, but only once. Since it is likely line-buffered, you could	1164	readable, but only once. Since it is likely line-buffered, you could
1165	attempt to read a whole line in the callback.	1165	attempt to read a whole line in the callback.
1166		1166
1167	static void	1167	static void
1168	stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)	1168	stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
1169	{	1169	{
1170	ev_io_stop (loop, w);	1170	ev_io_stop (loop, w);
1171	.. read from stdin here (or from w->fd) and haqndle any I/O errors	1171	.. read from stdin here (or from w->fd) and haqndle any I/O errors
1172	}	1172	}
1173		1173
1174	...	1174	...
1175	struct ev_loop *loop = ev_default_init (0);	1175	struct ev_loop *loop = ev_default_init (0);
1176	struct ev_io stdin_readable;	1176	struct ev_io stdin_readable;
1177	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1177	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1178	ev_io_start (loop, &stdin_readable);	1178	ev_io_start (loop, &stdin_readable);
1179	ev_loop (loop, 0);	1179	ev_loop (loop, 0);
1180		1180
1181		1181
1182	=head2 C<ev_timer> - relative and optionally repeating timeouts	1182	=head2 C<ev_timer> - relative and optionally repeating timeouts
1183		1183
1184	Timer watchers are simple relative timers that generate an event after a	1184	Timer watchers are simple relative timers that generate an event after a
1185	given time, and optionally repeating in regular intervals after that.	1185	given time, and optionally repeating in regular intervals after that.
1186		1186
1187	The timers are based on real time, that is, if you register an event that	1187	The timers are based on real time, that is, if you register an event that
1188	times out after an hour and you reset your system clock to january last	1188	times out after an hour and you reset your system clock to January last
1189	year, it will still time out after (roughly) and hour. "Roughly" because	1189	year, it will still time out after (roughly) and hour. "Roughly" because
1190	detecting time jumps is hard, and some inaccuracies are unavoidable (the	1190	detecting time jumps is hard, and some inaccuracies are unavoidable (the
1191	monotonic clock option helps a lot here).	1191	monotonic clock option helps a lot here).
1192		1192
1193	The relative timeouts are calculated relative to the C<ev_now ()>	1193	The relative timeouts are calculated relative to the C<ev_now ()>
…		…
1196	you suspect event processing to be delayed and you I<need> to base the timeout	1196	you suspect event processing to be delayed and you I<need> to base the timeout
1197	on the current time, use something like this to adjust for this:	1197	on the current time, use something like this to adjust for this:
1198		1198
1199	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);	1199	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
1200		1200
1201	The callback is guarenteed to be invoked only after its timeout has passed,	1201	The callback is guaranteed to be invoked only after its timeout has passed,
1202	but if multiple timers become ready during the same loop iteration then	1202	but if multiple timers become ready during the same loop iteration then
1203	order of execution is undefined.	1203	order of execution is undefined.
1204		1204
1205	=head3 Watcher-Specific Functions and Data Members	1205	=head3 Watcher-Specific Functions and Data Members
1206		1206
…		…
1227	This will act as if the timer timed out and restart it again if it is	1227	This will act as if the timer timed out and restart it again if it is
1228	repeating. The exact semantics are:	1228	repeating. The exact semantics are:
1229		1229
1230	If the timer is pending, its pending status is cleared.	1230	If the timer is pending, its pending status is cleared.
1231		1231
1232	If the timer is started but nonrepeating, stop it (as if it timed out).	1232	If the timer is started but non-repeating, stop it (as if it timed out).
1233		1233
1234	If the timer is repeating, either start it if necessary (with the	1234	If the timer is repeating, either start it if necessary (with the
1235	C<repeat> value), or reset the running timer to the C<repeat> value.	1235	C<repeat> value), or reset the running timer to the C<repeat> value.
1236		1236
1237	This sounds a bit complicated, but here is a useful and typical	1237	This sounds a bit complicated, but here is a useful and typical
1238	example: Imagine you have a tcp connection and you want a so-called idle	1238	example: Imagine you have a TCP connection and you want a so-called idle
1239	timeout, that is, you want to be called when there have been, say, 60	1239	timeout, that is, you want to be called when there have been, say, 60
1240	seconds of inactivity on the socket. The easiest way to do this is to	1240	seconds of inactivity on the socket. The easiest way to do this is to
1241	configure an C<ev_timer> with a C<repeat> value of C<60> and then call	1241	configure an C<ev_timer> with a C<repeat> value of C<60> and then call
1242	C<ev_timer_again> each time you successfully read or write some data. If	1242	C<ev_timer_again> each time you successfully read or write some data. If
1243	you go into an idle state where you do not expect data to travel on the	1243	you go into an idle state where you do not expect data to travel on the
…		…
1269		1269
1270	=head3 Examples	1270	=head3 Examples
1271		1271
1272	Example: Create a timer that fires after 60 seconds.	1272	Example: Create a timer that fires after 60 seconds.
1273		1273
1274	static void	1274	static void
1275	one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)	1275	one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
1276	{	1276	{
1277	.. one minute over, w is actually stopped right here	1277	.. one minute over, w is actually stopped right here
1278	}	1278	}
1279		1279
1280	struct ev_timer mytimer;	1280	struct ev_timer mytimer;
1281	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1281	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1282	ev_timer_start (loop, &mytimer);	1282	ev_timer_start (loop, &mytimer);
1283		1283
1284	Example: Create a timeout timer that times out after 10 seconds of	1284	Example: Create a timeout timer that times out after 10 seconds of
1285	inactivity.	1285	inactivity.
1286		1286
1287	static void	1287	static void
1288	timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)	1288	timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
1289	{	1289	{
1290	.. ten seconds without any activity	1290	.. ten seconds without any activity
1291	}	1291	}
1292		1292
1293	struct ev_timer mytimer;	1293	struct ev_timer mytimer;
1294	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	1294	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1295	ev_timer_again (&mytimer); /* start timer */	1295	ev_timer_again (&mytimer); /* start timer */
1296	ev_loop (loop, 0);	1296	ev_loop (loop, 0);
1297		1297
1298	// and in some piece of code that gets executed on any "activity":	1298	// and in some piece of code that gets executed on any "activity":
1299	// reset the timeout to start ticking again at 10 seconds	1299	// reset the timeout to start ticking again at 10 seconds
1300	ev_timer_again (&mytimer);	1300	ev_timer_again (&mytimer);
1301		1301
1302		1302
1303	=head2 C<ev_periodic> - to cron or not to cron?	1303	=head2 C<ev_periodic> - to cron or not to cron?
1304		1304
1305	Periodic watchers are also timers of a kind, but they are very versatile	1305	Periodic watchers are also timers of a kind, but they are very versatile
1306	(and unfortunately a bit complex).	1306	(and unfortunately a bit complex).
1307		1307
1308	Unlike C<ev_timer>'s, they are not based on real time (or relative time)	1308	Unlike C<ev_timer>'s, they are not based on real time (or relative time)
1309	but on wallclock time (absolute time). You can tell a periodic watcher	1309	but on wall clock time (absolute time). You can tell a periodic watcher
1310	to trigger after some specific point in time. For example, if you tell a	1310	to trigger after some specific point in time. For example, if you tell a
1311	periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now ()	1311	periodic watcher to trigger in 10 seconds (by specifying e.g. C<ev_now ()
1312	+ 10.>, that is, an absolute time not a delay) and then reset your system	1312	+ 10.>, that is, an absolute time not a delay) and then reset your system
1313	clock to january of the previous year, then it will take more than year	1313	clock to January of the previous year, then it will take more than year
1314	to trigger the event (unlike an C<ev_timer>, which would still trigger	1314	to trigger the event (unlike an C<ev_timer>, which would still trigger
1315	roughly 10 seconds later as it uses a relative timeout).	1315	roughly 10 seconds later as it uses a relative timeout).
1316		1316
1317	C<ev_periodic>s can also be used to implement vastly more complex timers,	1317	C<ev_periodic>s can also be used to implement vastly more complex timers,
1318	such as triggering an event on each "midnight, local time", or other	1318	such as triggering an event on each "midnight, local time", or other
1319	complicated, rules.	1319	complicated, rules.
1320		1320
1321	As with timers, the callback is guarenteed to be invoked only when the	1321	As with timers, the callback is guaranteed to be invoked only when the
1322	time (C<at>) has passed, but if multiple periodic timers become ready	1322	time (C<at>) has passed, but if multiple periodic timers become ready
1323	during the same loop iteration then order of execution is undefined.	1323	during the same loop iteration then order of execution is undefined.
1324		1324
1325	=head3 Watcher-Specific Functions and Data Members	1325	=head3 Watcher-Specific Functions and Data Members
1326		1326
…		…
1335		1335
1336	=over 4	1336	=over 4
1337		1337
1338	=item * absolute timer (at = time, interval = reschedule_cb = 0)	1338	=item * absolute timer (at = time, interval = reschedule_cb = 0)
1339		1339
1340	In this configuration the watcher triggers an event after the wallclock	1340	In this configuration the watcher triggers an event after the wall clock
1341	time C<at> has passed and doesn't repeat. It will not adjust when a time	1341	time C<at> has passed and doesn't repeat. It will not adjust when a time
1342	jump occurs, that is, if it is to be run at January 1st 2011 then it will	1342	jump occurs, that is, if it is to be run at January 1st 2011 then it will
1343	run when the system time reaches or surpasses this time.	1343	run when the system time reaches or surpasses this time.
1344		1344
1345	=item * repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)	1345	=item * repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)
…		…
1353	the hour:	1353	the hour:
1354		1354
1355	ev_periodic_set (&periodic, 0., 3600., 0);	1355	ev_periodic_set (&periodic, 0., 3600., 0);
1356		1356
1357	This doesn't mean there will always be 3600 seconds in between triggers,	1357	This doesn't mean there will always be 3600 seconds in between triggers,
1358	but only that the the callback will be called when the system time shows a	1358	but only that the callback will be called when the system time shows a
1359	full hour (UTC), or more correctly, when the system time is evenly divisible	1359	full hour (UTC), or more correctly, when the system time is evenly divisible
1360	by 3600.	1360	by 3600.
1361		1361
1362	Another way to think about it (for the mathematically inclined) is that	1362	Another way to think about it (for the mathematically inclined) is that
1363	C<ev_periodic> will try to run the callback in this mode at the next possible	1363	C<ev_periodic> will try to run the callback in this mode at the next possible
…		…
1365		1365
1366	For numerical stability it is preferable that the C<at> value is near	1366	For numerical stability it is preferable that the C<at> value is near
1367	C<ev_now ()> (the current time), but there is no range requirement for	1367	C<ev_now ()> (the current time), but there is no range requirement for
1368	this value, and in fact is often specified as zero.	1368	this value, and in fact is often specified as zero.
1369		1369
1370	Note also that there is an upper limit to how often a timer can fire (cpu	1370	Note also that there is an upper limit to how often a timer can fire (CPU
1371	speed for example), so if C<interval> is very small then timing stability	1371	speed for example), so if C<interval> is very small then timing stability
1372	will of course detoriate. Libev itself tries to be exact to be about one	1372	will of course deteriorate. Libev itself tries to be exact to be about one
1373	millisecond (if the OS supports it and the machine is fast enough).	1373	millisecond (if the OS supports it and the machine is fast enough).
1374		1374
1375	=item * manual reschedule mode (at and interval ignored, reschedule_cb = callback)	1375	=item * manual reschedule mode (at and interval ignored, reschedule_cb = callback)
1376		1376
1377	In this mode the values for C<interval> and C<at> are both being	1377	In this mode the values for C<interval> and C<at> are both being
…		…
1446		1446
1447	=head3 Examples	1447	=head3 Examples
1448		1448
1449	Example: Call a callback every hour, or, more precisely, whenever the	1449	Example: Call a callback every hour, or, more precisely, whenever the
1450	system clock is divisible by 3600. The callback invocation times have	1450	system clock is divisible by 3600. The callback invocation times have
1451	potentially a lot of jittering, but good long-term stability.	1451	potentially a lot of jitter, but good long-term stability.
1452		1452
1453	static void	1453	static void
1454	clock_cb (struct ev_loop *loop, struct ev_io *w, int revents)	1454	clock_cb (struct ev_loop *loop, struct ev_io *w, int revents)
1455	{	1455	{
1456	... its now a full hour (UTC, or TAI or whatever your clock follows)	1456	... its now a full hour (UTC, or TAI or whatever your clock follows)
1457	}	1457	}
1458		1458
1459	struct ev_periodic hourly_tick;	1459	struct ev_periodic hourly_tick;
1460	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1460	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1461	ev_periodic_start (loop, &hourly_tick);	1461	ev_periodic_start (loop, &hourly_tick);
1462		1462
1463	Example: The same as above, but use a reschedule callback to do it:	1463	Example: The same as above, but use a reschedule callback to do it:
1464		1464
1465	#include <math.h>	1465	#include <math.h>
1466		1466
1467	static ev_tstamp	1467	static ev_tstamp
1468	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1468	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1469	{	1469	{
1470	return fmod (now, 3600.) + 3600.;	1470	return fmod (now, 3600.) + 3600.;
1471	}	1471	}
1472		1472
1473	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1473	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1474		1474
1475	Example: Call a callback every hour, starting now:	1475	Example: Call a callback every hour, starting now:
1476		1476
1477	struct ev_periodic hourly_tick;	1477	struct ev_periodic hourly_tick;
1478	ev_periodic_init (&hourly_tick, clock_cb,	1478	ev_periodic_init (&hourly_tick, clock_cb,
1479	fmod (ev_now (loop), 3600.), 3600., 0);	1479	fmod (ev_now (loop), 3600.), 3600., 0);
1480	ev_periodic_start (loop, &hourly_tick);	1480	ev_periodic_start (loop, &hourly_tick);
1481		1481
1482		1482
1483	=head2 C<ev_signal> - signal me when a signal gets signalled!	1483	=head2 C<ev_signal> - signal me when a signal gets signalled!
1484		1484
1485	Signal watchers will trigger an event when the process receives a specific	1485	Signal watchers will trigger an event when the process receives a specific
…		…
1493	as you don't register any with libev). Similarly, when the last signal	1493	as you don't register any with libev). Similarly, when the last signal
1494	watcher for a signal is stopped libev will reset the signal handler to	1494	watcher for a signal is stopped libev will reset the signal handler to
1495	SIG_DFL (regardless of what it was set to before).	1495	SIG_DFL (regardless of what it was set to before).
1496		1496
1497	If possible and supported, libev will install its handlers with	1497	If possible and supported, libev will install its handlers with
1498	C<SA_RESTART> behaviour enabled, so syscalls should not be unduly	1498	C<SA_RESTART> behaviour enabled, so system calls should not be unduly
1499	interrupted. If you have a problem with syscalls getting interrupted by	1499	interrupted. If you have a problem with system calls getting interrupted by
1500	signals you can block all signals in an C<ev_check> watcher and unblock	1500	signals you can block all signals in an C<ev_check> watcher and unblock
1501	them in an C<ev_prepare> watcher.	1501	them in an C<ev_prepare> watcher.
1502		1502
1503	=head3 Watcher-Specific Functions and Data Members	1503	=head3 Watcher-Specific Functions and Data Members
1504		1504
…		…
1519		1519
1520	=head3 Examples	1520	=head3 Examples
1521		1521
1522	Example: Try to exit cleanly on SIGINT and SIGTERM.	1522	Example: Try to exit cleanly on SIGINT and SIGTERM.
1523		1523
1524	static void	1524	static void
1525	sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)	1525	sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
1526	{	1526	{
1527	ev_unloop (loop, EVUNLOOP_ALL);	1527	ev_unloop (loop, EVUNLOOP_ALL);
1528	}	1528	}
1529		1529
1530	struct ev_signal signal_watcher;	1530	struct ev_signal signal_watcher;
1531	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1531	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1532	ev_signal_start (loop, &sigint_cb);	1532	ev_signal_start (loop, &sigint_cb);
1533		1533
1534		1534
1535	=head2 C<ev_child> - watch out for process status changes	1535	=head2 C<ev_child> - watch out for process status changes
1536		1536
1537	Child watchers trigger when your process receives a SIGCHLD in response to	1537	Child watchers trigger when your process receives a SIGCHLD in response to
…		…
1539	is permissible to install a child watcher I<after> the child has been	1539	is permissible to install a child watcher I<after> the child has been
1540	forked (which implies it might have already exited), as long as the event	1540	forked (which implies it might have already exited), as long as the event
1541	loop isn't entered (or is continued from a watcher).	1541	loop isn't entered (or is continued from a watcher).
1542		1542
1543	Only the default event loop is capable of handling signals, and therefore	1543	Only the default event loop is capable of handling signals, and therefore
1544	you can only rgeister child watchers in the default event loop.	1544	you can only register child watchers in the default event loop.
1545		1545
1546	=head3 Process Interaction	1546	=head3 Process Interaction
1547		1547
1548	Libev grabs C<SIGCHLD> as soon as the default event loop is	1548	Libev grabs C<SIGCHLD> as soon as the default event loop is
1549	initialised. This is necessary to guarantee proper behaviour even if	1549	initialised. This is necessary to guarantee proper behaviour even if
1550	the first child watcher is started after the child exits. The occurance	1550	the first child watcher is started after the child exits. The occurrence
1551	of C<SIGCHLD> is recorded asynchronously, but child reaping is done	1551	of C<SIGCHLD> is recorded asynchronously, but child reaping is done
1552	synchronously as part of the event loop processing. Libev always reaps all	1552	synchronously as part of the event loop processing. Libev always reaps all
1553	children, even ones not watched.	1553	children, even ones not watched.
1554		1554
1555	=head3 Overriding the Built-In Processing	1555	=head3 Overriding the Built-In Processing
…		…
1597	=head3 Examples	1597	=head3 Examples
1598		1598
1599	Example: C<fork()> a new process and install a child handler to wait for	1599	Example: C<fork()> a new process and install a child handler to wait for
1600	its completion.	1600	its completion.
1601		1601
1602	ev_child cw;	1602	ev_child cw;
1603		1603
1604	static void	1604	static void
1605	child_cb (EV_P_ struct ev_child *w, int revents)	1605	child_cb (EV_P_ struct ev_child *w, int revents)
1606	{	1606	{
1607	ev_child_stop (EV_A_ w);	1607	ev_child_stop (EV_A_ w);
1608	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);	1608	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
1609	}	1609	}
1610		1610
1611	pid_t pid = fork ();	1611	pid_t pid = fork ();
1612		1612
1613	if (pid < 0)	1613	if (pid < 0)
1614	// error	1614	// error
1615	else if (pid == 0)	1615	else if (pid == 0)
1616	{	1616	{
1617	// the forked child executes here	1617	// the forked child executes here
1618	exit (1);	1618	exit (1);
1619	}	1619	}
1620	else	1620	else
1621	{	1621	{
1622	ev_child_init (&cw, child_cb, pid, 0);	1622	ev_child_init (&cw, child_cb, pid, 0);
1623	ev_child_start (EV_DEFAULT_ &cw);	1623	ev_child_start (EV_DEFAULT_ &cw);
1624	}	1624	}
1625		1625
1626		1626
1627	=head2 C<ev_stat> - did the file attributes just change?	1627	=head2 C<ev_stat> - did the file attributes just change?
1628		1628
1629	This watches a filesystem path for attribute changes. That is, it calls	1629	This watches a file system path for attribute changes. That is, it calls
1630	C<stat> regularly (or when the OS says it changed) and sees if it changed	1630	C<stat> regularly (or when the OS says it changed) and sees if it changed
1631	compared to the last time, invoking the callback if it did.	1631	compared to the last time, invoking the callback if it did.
1632		1632
1633	The path does not need to exist: changing from "path exists" to "path does	1633	The path does not need to exist: changing from "path exists" to "path does
1634	not exist" is a status change like any other. The condition "path does	1634	not exist" is a status change like any other. The condition "path does
…		…
1668	disabled large file support, you get the 32 bit version of the stat	1668	disabled large file support, you get the 32 bit version of the stat
1669	structure. When using the library from programs that change the ABI to	1669	structure. When using the library from programs that change the ABI to
1670	use 64 bit file offsets the programs will fail. In that case you have to	1670	use 64 bit file offsets the programs will fail. In that case you have to
1671	compile libev with the same flags to get binary compatibility. This is	1671	compile libev with the same flags to get binary compatibility. This is
1672	obviously the case with any flags that change the ABI, but the problem is	1672	obviously the case with any flags that change the ABI, but the problem is
1673	most noticably with ev_stat and largefile support.	1673	most noticeably with ev_stat and large file support.
1674		1674
1675	=head3 Inotify	1675	=head3 Inotify
1676		1676
1677	When C<inotify (7)> support has been compiled into libev (generally only	1677	When C<inotify (7)> support has been compiled into libev (generally only
1678	available on Linux) and present at runtime, it will be used to speed up	1678	available on Linux) and present at runtime, it will be used to speed up
…		…
1688	implement this functionality, due to the requirement of having a file	1688	implement this functionality, due to the requirement of having a file
1689	descriptor open on the object at all times).	1689	descriptor open on the object at all times).
1690		1690
1691	=head3 The special problem of stat time resolution	1691	=head3 The special problem of stat time resolution
1692		1692
1693	The C<stat ()> syscall only supports full-second resolution portably, and	1693	The C<stat ()> system call only supports full-second resolution portably, and
1694	even on systems where the resolution is higher, many filesystems still	1694	even on systems where the resolution is higher, many file systems still
1695	only support whole seconds.	1695	only support whole seconds.
1696		1696
1697	That means that, if the time is the only thing that changes, you can	1697	That means that, if the time is the only thing that changes, you can
1698	easily miss updates: on the first update, C<ev_stat> detects a change and	1698	easily miss updates: on the first update, C<ev_stat> detects a change and
1699	calls your callback, which does something. When there is another update	1699	calls your callback, which does something. When there is another update
…		…
1759		1759
1760	The specified interval.	1760	The specified interval.
1761		1761
1762	=item const char *path [read-only]	1762	=item const char *path [read-only]
1763		1763
1764	The filesystem path that is being watched.	1764	The file system path that is being watched.
1765		1765
1766	=back	1766	=back
1767		1767
1768	=head3 Examples	1768	=head3 Examples
1769		1769
1770	Example: Watch C</etc/passwd> for attribute changes.	1770	Example: Watch C</etc/passwd> for attribute changes.
1771		1771
1772	static void	1772	static void
1773	passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)	1773	passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
1774	{	1774	{
1775	/* /etc/passwd changed in some way */	1775	/* /etc/passwd changed in some way */
1776	if (w->attr.st_nlink)	1776	if (w->attr.st_nlink)
1777	{	1777	{
1778	printf ("passwd current size %ld\n", (long)w->attr.st_size);	1778	printf ("passwd current size %ld\n", (long)w->attr.st_size);
1779	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);	1779	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
1780	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);	1780	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
1781	}	1781	}
1782	else	1782	else
1783	/* you shalt not abuse printf for puts */	1783	/* you shalt not abuse printf for puts */
1784	puts ("wow, /etc/passwd is not there, expect problems. "	1784	puts ("wow, /etc/passwd is not there, expect problems. "
1785	"if this is windows, they already arrived\n");	1785	"if this is windows, they already arrived\n");
1786	}	1786	}
1787		1787
1788	...	1788	...
1789	ev_stat passwd;	1789	ev_stat passwd;
1790		1790
1791	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);	1791	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
1792	ev_stat_start (loop, &passwd);	1792	ev_stat_start (loop, &passwd);
1793		1793
1794	Example: Like above, but additionally use a one-second delay so we do not	1794	Example: Like above, but additionally use a one-second delay so we do not
1795	miss updates (however, frequent updates will delay processing, too, so	1795	miss updates (however, frequent updates will delay processing, too, so
1796	one might do the work both on C<ev_stat> callback invocation I<and> on	1796	one might do the work both on C<ev_stat> callback invocation I<and> on
1797	C<ev_timer> callback invocation).	1797	C<ev_timer> callback invocation).
1798		1798
1799	static ev_stat passwd;	1799	static ev_stat passwd;
1800	static ev_timer timer;	1800	static ev_timer timer;
1801		1801
1802	static void	1802	static void
1803	timer_cb (EV_P_ ev_timer *w, int revents)	1803	timer_cb (EV_P_ ev_timer *w, int revents)
1804	{	1804	{
1805	ev_timer_stop (EV_A_ w);	1805	ev_timer_stop (EV_A_ w);
1806		1806
1807	/* now it's one second after the most recent passwd change */	1807	/* now it's one second after the most recent passwd change */
1808	}	1808	}
1809		1809
1810	static void	1810	static void
1811	stat_cb (EV_P_ ev_stat *w, int revents)	1811	stat_cb (EV_P_ ev_stat *w, int revents)
1812	{	1812	{
1813	/* reset the one-second timer */	1813	/* reset the one-second timer */
1814	ev_timer_again (EV_A_ &timer);	1814	ev_timer_again (EV_A_ &timer);
1815	}	1815	}
1816		1816
1817	...	1817	...
1818	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);	1818	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
1819	ev_stat_start (loop, &passwd);	1819	ev_stat_start (loop, &passwd);
1820	ev_timer_init (&timer, timer_cb, 0., 1.02);	1820	ev_timer_init (&timer, timer_cb, 0., 1.02);
1821		1821
1822		1822
1823	=head2 C<ev_idle> - when you've got nothing better to do...	1823	=head2 C<ev_idle> - when you've got nothing better to do...
1824		1824
1825	Idle watchers trigger events when no other events of the same or higher	1825	Idle watchers trigger events when no other events of the same or higher
…		…
1856	=head3 Examples	1856	=head3 Examples
1857		1857
1858	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the	1858	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1859	callback, free it. Also, use no error checking, as usual.	1859	callback, free it. Also, use no error checking, as usual.
1860		1860
1861	static void	1861	static void
1862	idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)	1862	idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
1863	{	1863	{
1864	free (w);	1864	free (w);
1865	// now do something you wanted to do when the program has	1865	// now do something you wanted to do when the program has
1866	// no longer anything immediate to do.	1866	// no longer anything immediate to do.
1867	}	1867	}
1868		1868
1869	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1869	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1870	ev_idle_init (idle_watcher, idle_cb);	1870	ev_idle_init (idle_watcher, idle_cb);
1871	ev_idle_start (loop, idle_cb);	1871	ev_idle_start (loop, idle_cb);
1872		1872
1873		1873
1874	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!	1874	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
1875		1875
1876	Prepare and check watchers are usually (but not always) used in tandem:	1876	Prepare and check watchers are usually (but not always) used in tandem:
…		…
1895		1895
1896	This is done by examining in each prepare call which file descriptors need	1896	This is done by examining in each prepare call which file descriptors need
1897	to be watched by the other library, registering C<ev_io> watchers for	1897	to be watched by the other library, registering C<ev_io> watchers for
1898	them and starting an C<ev_timer> watcher for any timeouts (many libraries	1898	them and starting an C<ev_timer> watcher for any timeouts (many libraries
1899	provide just this functionality). Then, in the check watcher you check for	1899	provide just this functionality). Then, in the check watcher you check for
1900	any events that occured (by checking the pending status of all watchers	1900	any events that occurred (by checking the pending status of all watchers
1901	and stopping them) and call back into the library. The I/O and timer	1901	and stopping them) and call back into the library. The I/O and timer
1902	callbacks will never actually be called (but must be valid nevertheless,	1902	callbacks will never actually be called (but must be valid nevertheless,
1903	because you never know, you know?).	1903	because you never know, you know?).
1904		1904
1905	As another example, the Perl Coro module uses these hooks to integrate	1905	As another example, the Perl Coro module uses these hooks to integrate
…		…
1948	and in a check watcher, destroy them and call into libadns. What follows	1948	and in a check watcher, destroy them and call into libadns. What follows
1949	is pseudo-code only of course. This requires you to either use a low	1949	is pseudo-code only of course. This requires you to either use a low
1950	priority for the check watcher or use C<ev_clear_pending> explicitly, as	1950	priority for the check watcher or use C<ev_clear_pending> explicitly, as
1951	the callbacks for the IO/timeout watchers might not have been called yet.	1951	the callbacks for the IO/timeout watchers might not have been called yet.
1952		1952
1953	static ev_io iow [nfd];	1953	static ev_io iow [nfd];
1954	static ev_timer tw;	1954	static ev_timer tw;
1955		1955
1956	static void	1956	static void
1957	io_cb (ev_loop *loop, ev_io *w, int revents)	1957	io_cb (ev_loop *loop, ev_io *w, int revents)
1958	{	1958	{
1959	}	1959	}
1960		1960
1961	// create io watchers for each fd and a timer before blocking	1961	// create io watchers for each fd and a timer before blocking
1962	static void	1962	static void
1963	adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)	1963	adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)
1964	{	1964	{
1965	int timeout = 3600000;	1965	int timeout = 3600000;
1966	struct pollfd fds [nfd];	1966	struct pollfd fds [nfd];
1967	// actual code will need to loop here and realloc etc.	1967	// actual code will need to loop here and realloc etc.
1968	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1968	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1969		1969
1970	/* the callback is illegal, but won't be called as we stop during check */	1970	/* the callback is illegal, but won't be called as we stop during check */
1971	ev_timer_init (&tw, 0, timeout * 1e-3);	1971	ev_timer_init (&tw, 0, timeout * 1e-3);
1972	ev_timer_start (loop, &tw);	1972	ev_timer_start (loop, &tw);
1973		1973
1974	// create one ev_io per pollfd	1974	// create one ev_io per pollfd
1975	for (int i = 0; i < nfd; ++i)	1975	for (int i = 0; i < nfd; ++i)
1976	{	1976	{
1977	ev_io_init (iow + i, io_cb, fds [i].fd,	1977	ev_io_init (iow + i, io_cb, fds [i].fd,
1978	((fds [i].events & POLLIN ? EV_READ : 0)	1978	((fds [i].events & POLLIN ? EV_READ : 0)
1979	| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	1979	| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1980		1980
1981	fds [i].revents = 0;	1981	fds [i].revents = 0;
1982	ev_io_start (loop, iow + i);	1982	ev_io_start (loop, iow + i);
1983	}	1983	}
1984	}	1984	}
1985		1985
1986	// stop all watchers after blocking	1986	// stop all watchers after blocking
1987	static void	1987	static void
1988	adns_check_cb (ev_loop *loop, ev_check *w, int revents)	1988	adns_check_cb (ev_loop *loop, ev_check *w, int revents)
1989	{	1989	{
1990	ev_timer_stop (loop, &tw);	1990	ev_timer_stop (loop, &tw);
1991		1991
1992	for (int i = 0; i < nfd; ++i)	1992	for (int i = 0; i < nfd; ++i)
1993	{	1993	{
1994	// set the relevant poll flags	1994	// set the relevant poll flags
1995	// could also call adns_processreadable etc. here	1995	// could also call adns_processreadable etc. here
1996	struct pollfd *fd = fds + i;	1996	struct pollfd *fd = fds + i;
1997	int revents = ev_clear_pending (iow + i);	1997	int revents = ev_clear_pending (iow + i);
1998	if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;	1998	if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
1999	if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;	1999	if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
2000		2000
2001	// now stop the watcher	2001	// now stop the watcher
2002	ev_io_stop (loop, iow + i);	2002	ev_io_stop (loop, iow + i);
2003	}	2003	}
2004		2004
2005	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	2005	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
2006	}	2006	}
2007		2007
2008	Method 2: This would be just like method 1, but you run C<adns_afterpoll>	2008	Method 2: This would be just like method 1, but you run C<adns_afterpoll>
2009	in the prepare watcher and would dispose of the check watcher.	2009	in the prepare watcher and would dispose of the check watcher.
2010		2010
2011	Method 3: If the module to be embedded supports explicit event	2011	Method 3: If the module to be embedded supports explicit event
2012	notification (adns does), you can also make use of the actual watcher	2012	notification (libadns does), you can also make use of the actual watcher
2013	callbacks, and only destroy/create the watchers in the prepare watcher.	2013	callbacks, and only destroy/create the watchers in the prepare watcher.
2014		2014
2015	static void	2015	static void
2016	timer_cb (EV_P_ ev_timer *w, int revents)	2016	timer_cb (EV_P_ ev_timer *w, int revents)
2017	{	2017	{
2018	adns_state ads = (adns_state)w->data;	2018	adns_state ads = (adns_state)w->data;
2019	update_now (EV_A);	2019	update_now (EV_A);
2020		2020
2021	adns_processtimeouts (ads, &tv_now);	2021	adns_processtimeouts (ads, &tv_now);
2022	}	2022	}
2023		2023
2024	static void	2024	static void
2025	io_cb (EV_P_ ev_io *w, int revents)	2025	io_cb (EV_P_ ev_io *w, int revents)
2026	{	2026	{
2027	adns_state ads = (adns_state)w->data;	2027	adns_state ads = (adns_state)w->data;
2028	update_now (EV_A);	2028	update_now (EV_A);
2029		2029
2030	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);	2030	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
2031	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);	2031	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
2032	}	2032	}
2033		2033
2034	// do not ever call adns_afterpoll	2034	// do not ever call adns_afterpoll
2035		2035
2036	Method 4: Do not use a prepare or check watcher because the module you	2036	Method 4: Do not use a prepare or check watcher because the module you
2037	want to embed is too inflexible to support it. Instead, youc na override	2037	want to embed is too inflexible to support it. Instead, you can override
2038	their poll function. The drawback with this solution is that the main	2038	their poll function. The drawback with this solution is that the main
2039	loop is now no longer controllable by EV. The C<Glib::EV> module does	2039	loop is now no longer controllable by EV. The C<Glib::EV> module does
2040	this.	2040	this.
2041		2041
2042	static gint	2042	static gint
2043	event_poll_func (GPollFD *fds, guint nfds, gint timeout)	2043	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
2044	{	2044	{
2045	int got_events = 0;	2045	int got_events = 0;
2046		2046
2047	for (n = 0; n < nfds; ++n)	2047	for (n = 0; n < nfds; ++n)
2048	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events	2048	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
2049		2049
2050	if (timeout >= 0)	2050	if (timeout >= 0)
2051	// create/start timer	2051	// create/start timer
2052		2052
2053	// poll	2053	// poll
2054	ev_loop (EV_A_ 0);	2054	ev_loop (EV_A_ 0);
2055		2055
2056	// stop timer again	2056	// stop timer again
2057	if (timeout >= 0)	2057	if (timeout >= 0)
2058	ev_timer_stop (EV_A_ &to);	2058	ev_timer_stop (EV_A_ &to);
2059		2059
2060	// stop io watchers again - their callbacks should have set	2060	// stop io watchers again - their callbacks should have set
2061	for (n = 0; n < nfds; ++n)	2061	for (n = 0; n < nfds; ++n)
2062	ev_io_stop (EV_A_ iow [n]);	2062	ev_io_stop (EV_A_ iow [n]);
2063		2063
2064	return got_events;	2064	return got_events;
2065	}	2065	}
2066		2066
2067		2067
2068	=head2 C<ev_embed> - when one backend isn't enough...	2068	=head2 C<ev_embed> - when one backend isn't enough...
2069		2069
2070	This is a rather advanced watcher type that lets you embed one event loop	2070	This is a rather advanced watcher type that lets you embed one event loop
…		…
2126		2126
2127	Configures the watcher to embed the given loop, which must be	2127	Configures the watcher to embed the given loop, which must be
2128	embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be	2128	embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be
2129	invoked automatically, otherwise it is the responsibility of the callback	2129	invoked automatically, otherwise it is the responsibility of the callback
2130	to invoke it (it will continue to be called until the sweep has been done,	2130	to invoke it (it will continue to be called until the sweep has been done,
2131	if you do not want thta, you need to temporarily stop the embed watcher).	2131	if you do not want that, you need to temporarily stop the embed watcher).
2132		2132
2133	=item ev_embed_sweep (loop, ev_embed *)	2133	=item ev_embed_sweep (loop, ev_embed *)
2134		2134
2135	Make a single, non-blocking sweep over the embedded loop. This works	2135	Make a single, non-blocking sweep over the embedded loop. This works
2136	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most	2136	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
2137	apropriate way for embedded loops.	2137	appropriate way for embedded loops.
2138		2138
2139	=item struct ev_loop *other [read-only]	2139	=item struct ev_loop *other [read-only]
2140		2140
2141	The embedded event loop.	2141	The embedded event loop.
2142		2142
…		…
2144		2144
2145	=head3 Examples	2145	=head3 Examples
2146		2146
2147	Example: Try to get an embeddable event loop and embed it into the default	2147	Example: Try to get an embeddable event loop and embed it into the default
2148	event loop. If that is not possible, use the default loop. The default	2148	event loop. If that is not possible, use the default loop. The default
2149	loop is stored in C<loop_hi>, while the mebeddable loop is stored in	2149	loop is stored in C<loop_hi>, while the embeddable loop is stored in
2150	C<loop_lo> (which is C<loop_hi> in the acse no embeddable loop can be	2150	C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
2151	used).	2151	used).
2152		2152
2153	struct ev_loop *loop_hi = ev_default_init (0);	2153	struct ev_loop *loop_hi = ev_default_init (0);
2154	struct ev_loop *loop_lo = 0;	2154	struct ev_loop *loop_lo = 0;
2155	struct ev_embed embed;	2155	struct ev_embed embed;
2156		2156
2157	// see if there is a chance of getting one that works	2157	// see if there is a chance of getting one that works
2158	// (remember that a flags value of 0 means autodetection)	2158	// (remember that a flags value of 0 means autodetection)
2159	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()	2159	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
2160	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())	2160	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
2161	: 0;	2161	: 0;
2162		2162
2163	// if we got one, then embed it, otherwise default to loop_hi	2163	// if we got one, then embed it, otherwise default to loop_hi
2164	if (loop_lo)	2164	if (loop_lo)
2165	{	2165	{
2166	ev_embed_init (&embed, 0, loop_lo);	2166	ev_embed_init (&embed, 0, loop_lo);
2167	ev_embed_start (loop_hi, &embed);	2167	ev_embed_start (loop_hi, &embed);
2168	}	2168	}
2169	else	2169	else
2170	loop_lo = loop_hi;	2170	loop_lo = loop_hi;
2171		2171
2172	Example: Check if kqueue is available but not recommended and create	2172	Example: Check if kqueue is available but not recommended and create
2173	a kqueue backend for use with sockets (which usually work with any	2173	a kqueue backend for use with sockets (which usually work with any
2174	kqueue implementation). Store the kqueue/socket-only event loop in	2174	kqueue implementation). Store the kqueue/socket-only event loop in
2175	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).	2175	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
2176		2176
2177	struct ev_loop *loop = ev_default_init (0);	2177	struct ev_loop *loop = ev_default_init (0);
2178	struct ev_loop *loop_socket = 0;	2178	struct ev_loop *loop_socket = 0;
2179	struct ev_embed embed;	2179	struct ev_embed embed;
2180		2180
2181	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)	2181	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
2182	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))	2182	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
2183	{	2183	{
2184	ev_embed_init (&embed, 0, loop_socket);	2184	ev_embed_init (&embed, 0, loop_socket);
2185	ev_embed_start (loop, &embed);	2185	ev_embed_start (loop, &embed);
2186	}	2186	}
2187		2187
2188	if (!loop_socket)	2188	if (!loop_socket)
2189	loop_socket = loop;	2189	loop_socket = loop;
2190		2190
2191	// now use loop_socket for all sockets, and loop for everything else	2191	// now use loop_socket for all sockets, and loop for everything else
2192		2192
2193		2193
2194	=head2 C<ev_fork> - the audacity to resume the event loop after a fork	2194	=head2 C<ev_fork> - the audacity to resume the event loop after a fork
2195		2195
2196	Fork watchers are called when a C<fork ()> was detected (usually because	2196	Fork watchers are called when a C<fork ()> was detected (usually because
…		…
2249		2249
2250	=item queueing from a signal handler context	2250	=item queueing from a signal handler context
2251		2251
2252	To implement race-free queueing, you simply add to the queue in the signal	2252	To implement race-free queueing, you simply add to the queue in the signal
2253	handler but you block the signal handler in the watcher callback. Here is an example that does that for	2253	handler but you block the signal handler in the watcher callback. Here is an example that does that for
2254	some fictitiuous SIGUSR1 handler:	2254	some fictitious SIGUSR1 handler:
2255		2255
2256	static ev_async mysig;	2256	static ev_async mysig;
2257		2257
2258	static void	2258	static void
2259	sigusr1_handler (void)	2259	sigusr1_handler (void)
…		…
2333	=item ev_async_send (loop, ev_async *)	2333	=item ev_async_send (loop, ev_async *)
2334		2334
2335	Sends/signals/activates the given C<ev_async> watcher, that is, feeds	2335	Sends/signals/activates the given C<ev_async> watcher, that is, feeds
2336	an C<EV_ASYNC> event on the watcher into the event loop. Unlike	2336	an C<EV_ASYNC> event on the watcher into the event loop. Unlike
2337	C<ev_feed_event>, this call is safe to do in other threads, signal or	2337	C<ev_feed_event>, this call is safe to do in other threads, signal or
2338	similar contexts (see the dicusssion of C<EV_ATOMIC_T> in the embedding	2338	similar contexts (see the discussion of C<EV_ATOMIC_T> in the embedding
2339	section below on what exactly this means).	2339	section below on what exactly this means).
2340		2340
2341	This call incurs the overhead of a syscall only once per loop iteration,	2341	This call incurs the overhead of a system call only once per loop iteration,
2342	so while the overhead might be noticable, it doesn't apply to repeated	2342	so while the overhead might be noticeable, it doesn't apply to repeated
2343	calls to C<ev_async_send>.	2343	calls to C<ev_async_send>.
2344		2344
2345	=item bool = ev_async_pending (ev_async *)	2345	=item bool = ev_async_pending (ev_async *)
2346		2346
2347	Returns a non-zero value when C<ev_async_send> has been called on the	2347	Returns a non-zero value when C<ev_async_send> has been called on the
…		…
2349	event loop.	2349	event loop.
2350		2350
2351	C<ev_async_send> sets a flag in the watcher and wakes up the loop. When	2351	C<ev_async_send> sets a flag in the watcher and wakes up the loop. When
2352	the loop iterates next and checks for the watcher to have become active,	2352	the loop iterates next and checks for the watcher to have become active,
2353	it will reset the flag again. C<ev_async_pending> can be used to very	2353	it will reset the flag again. C<ev_async_pending> can be used to very
2354	quickly check wether invoking the loop might be a good idea.	2354	quickly check whether invoking the loop might be a good idea.
2355		2355
2356	Not that this does I<not> check wether the watcher itself is pending, only	2356	Not that this does I<not> check whether the watcher itself is pending, only
2357	wether it has been requested to make this watcher pending.	2357	whether it has been requested to make this watcher pending.
2358		2358
2359	=back	2359	=back
2360		2360
2361		2361
2362	=head1 OTHER FUNCTIONS	2362	=head1 OTHER FUNCTIONS
…		…
2373	or timeout without having to allocate/configure/start/stop/free one or	2373	or timeout without having to allocate/configure/start/stop/free one or
2374	more watchers yourself.	2374	more watchers yourself.
2375		2375
2376	If C<fd> is less than 0, then no I/O watcher will be started and events	2376	If C<fd> is less than 0, then no I/O watcher will be started and events
2377	is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and	2377	is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and
2378	C<events> set will be craeted and started.	2378	C<events> set will be created and started.
2379		2379
2380	If C<timeout> is less than 0, then no timeout watcher will be	2380	If C<timeout> is less than 0, then no timeout watcher will be
2381	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and	2381	started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
2382	repeat = 0) will be started. While C<0> is a valid timeout, it is of	2382	repeat = 0) will be started. While C<0> is a valid timeout, it is of
2383	dubious value.	2383	dubious value.
…		…
2385	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	2385	The callback has the type C<void (*cb)(int revents, void *arg)> and gets
2386	passed an C<revents> set like normal event callbacks (a combination of	2386	passed an C<revents> set like normal event callbacks (a combination of
2387	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>	2387	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
2388	value passed to C<ev_once>:	2388	value passed to C<ev_once>:
2389		2389
2390	static void stdin_ready (int revents, void *arg)	2390	static void stdin_ready (int revents, void *arg)
2391	{	2391	{
2392	if (revents & EV_TIMEOUT)	2392	if (revents & EV_TIMEOUT)
2393	/* doh, nothing entered */;	2393	/* doh, nothing entered */;
2394	else if (revents & EV_READ)	2394	else if (revents & EV_READ)
2395	/* stdin might have data for us, joy! */;	2395	/* stdin might have data for us, joy! */;
2396	}	2396	}
2397		2397
2398	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2398	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2399		2399
2400	=item ev_feed_event (ev_loop *, watcher *, int revents)	2400	=item ev_feed_event (ev_loop *, watcher *, int revents)
2401		2401
2402	Feeds the given event set into the event loop, as if the specified event	2402	Feeds the given event set into the event loop, as if the specified event
2403	had happened for the specified watcher (which must be a pointer to an	2403	had happened for the specified watcher (which must be a pointer to an
…		…
2408	Feed an event on the given fd, as if a file descriptor backend detected	2408	Feed an event on the given fd, as if a file descriptor backend detected
2409	the given events it.	2409	the given events it.
2410		2410
2411	=item ev_feed_signal_event (ev_loop *loop, int signum)	2411	=item ev_feed_signal_event (ev_loop *loop, int signum)
2412		2412
2413	Feed an event as if the given signal occured (C<loop> must be the default	2413	Feed an event as if the given signal occurred (C<loop> must be the default
2414	loop!).	2414	loop!).
2415		2415
2416	=back	2416	=back
2417		2417
2418		2418
…		…
2447	=back	2447	=back
2448		2448
2449	=head1 C++ SUPPORT	2449	=head1 C++ SUPPORT
2450		2450
2451	Libev comes with some simplistic wrapper classes for C++ that mainly allow	2451	Libev comes with some simplistic wrapper classes for C++ that mainly allow
2452	you to use some convinience methods to start/stop watchers and also change	2452	you to use some convenience methods to start/stop watchers and also change
2453	the callback model to a model using method callbacks on objects.	2453	the callback model to a model using method callbacks on objects.
2454		2454
2455	To use it,	2455	To use it,
2456		2456
2457	#include <ev++.h>	2457	#include <ev++.h>
2458		2458
2459	This automatically includes F<ev.h> and puts all of its definitions (many	2459	This automatically includes F<ev.h> and puts all of its definitions (many
2460	of them macros) into the global namespace. All C++ specific things are	2460	of them macros) into the global namespace. All C++ specific things are
2461	put into the C<ev> namespace. It should support all the same embedding	2461	put into the C<ev> namespace. It should support all the same embedding
2462	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.	2462	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
…		…
2529	your compiler is good :), then the method will be fully inlined into the	2529	your compiler is good :), then the method will be fully inlined into the
2530	thunking function, making it as fast as a direct C callback.	2530	thunking function, making it as fast as a direct C callback.
2531		2531
2532	Example: simple class declaration and watcher initialisation	2532	Example: simple class declaration and watcher initialisation
2533		2533
2534	struct myclass	2534	struct myclass
2535	{	2535	{
2536	void io_cb (ev::io &w, int revents) { }	2536	void io_cb (ev::io &w, int revents) { }
2537	}	2537	}
2538		2538
2539	myclass obj;	2539	myclass obj;
2540	ev::io iow;	2540	ev::io iow;
2541	iow.set <myclass, &myclass::io_cb> (&obj);	2541	iow.set <myclass, &myclass::io_cb> (&obj);
2542		2542
2543	=item w->set<function> (void *data = 0)	2543	=item w->set<function> (void *data = 0)
2544		2544
2545	Also sets a callback, but uses a static method or plain function as	2545	Also sets a callback, but uses a static method or plain function as
2546	callback. The optional C<data> argument will be stored in the watcher's	2546	callback. The optional C<data> argument will be stored in the watcher's
…		…
2550		2550
2551	See the method-C<set> above for more details.	2551	See the method-C<set> above for more details.
2552		2552
2553	Example:	2553	Example:
2554		2554
2555	static void io_cb (ev::io &w, int revents) { }	2555	static void io_cb (ev::io &w, int revents) { }
2556	iow.set <io_cb> ();	2556	iow.set <io_cb> ();
2557		2557
2558	=item w->set (struct ev_loop *)	2558	=item w->set (struct ev_loop *)
2559		2559
2560	Associates a different C<struct ev_loop> with this watcher. You can only	2560	Associates a different C<struct ev_loop> with this watcher. You can only
2561	do this when the watcher is inactive (and not pending either).	2561	do this when the watcher is inactive (and not pending either).
2562		2562
2563	=item w->set ([args])	2563	=item w->set ([arguments])
2564		2564
2565	Basically the same as C<ev_TYPE_set>, with the same args. Must be	2565	Basically the same as C<ev_TYPE_set>, with the same arguments. Must be
2566	called at least once. Unlike the C counterpart, an active watcher gets	2566	called at least once. Unlike the C counterpart, an active watcher gets
2567	automatically stopped and restarted when reconfiguring it with this	2567	automatically stopped and restarted when reconfiguring it with this
2568	method.	2568	method.
2569		2569
2570	=item w->start ()	2570	=item w->start ()
…		…
2594	=back	2594	=back
2595		2595
2596	Example: Define a class with an IO and idle watcher, start one of them in	2596	Example: Define a class with an IO and idle watcher, start one of them in
2597	the constructor.	2597	the constructor.
2598		2598
2599	class myclass	2599	class myclass
2600	{	2600	{
2601	ev::io io; void io_cb (ev::io &w, int revents);	2601	ev::io io; void io_cb (ev::io &w, int revents);
2602	ev:idle idle void idle_cb (ev::idle &w, int revents);	2602	ev:idle idle void idle_cb (ev::idle &w, int revents);
2603		2603
2604	myclass (int fd)	2604	myclass (int fd)
2605	{	2605	{
2606	io .set <myclass, &myclass::io_cb > (this);	2606	io .set <myclass, &myclass::io_cb > (this);
2607	idle.set <myclass, &myclass::idle_cb> (this);	2607	idle.set <myclass, &myclass::idle_cb> (this);
2608		2608
2609	io.start (fd, ev::READ);	2609	io.start (fd, ev::READ);
2610	}	2610	}
2611	};	2611	};
2612		2612
2613		2613
2614	=head1 OTHER LANGUAGE BINDINGS	2614	=head1 OTHER LANGUAGE BINDINGS
2615		2615
2616	Libev does not offer other language bindings itself, but bindings for a	2616	Libev does not offer other language bindings itself, but bindings for a
2617	numbe rof languages exist in the form of third-party packages. If you know	2617	number of languages exist in the form of third-party packages. If you know
2618	any interesting language binding in addition to the ones listed here, drop	2618	any interesting language binding in addition to the ones listed here, drop
2619	me a note.	2619	me a note.
2620		2620
2621	=over 4	2621	=over 4
2622		2622
…		…
2632	L<http://software.schmorp.de/pkg/EV>.	2632	L<http://software.schmorp.de/pkg/EV>.
2633		2633
2634	=item Ruby	2634	=item Ruby
2635		2635
2636	Tony Arcieri has written a ruby extension that offers access to a subset	2636	Tony Arcieri has written a ruby extension that offers access to a subset
2637	of the libev API and adds filehandle abstractions, asynchronous DNS and	2637	of the libev API and adds file handle abstractions, asynchronous DNS and
2638	more on top of it. It can be found via gem servers. Its homepage is at	2638	more on top of it. It can be found via gem servers. Its homepage is at
2639	L<http://rev.rubyforge.org/>.	2639	L<http://rev.rubyforge.org/>.
2640		2640
2641	=item D	2641	=item D
2642		2642
…		…
2646	=back	2646	=back
2647		2647
2648		2648
2649	=head1 MACRO MAGIC	2649	=head1 MACRO MAGIC
2650		2650
2651	Libev can be compiled with a variety of options, the most fundamantal	2651	Libev can be compiled with a variety of options, the most fundamental
2652	of which is C<EV_MULTIPLICITY>. This option determines whether (most)	2652	of which is C<EV_MULTIPLICITY>. This option determines whether (most)
2653	functions and callbacks have an initial C<struct ev_loop *> argument.	2653	functions and callbacks have an initial C<struct ev_loop *> argument.
2654		2654
2655	To make it easier to write programs that cope with either variant, the	2655	To make it easier to write programs that cope with either variant, the
2656	following macros are defined:	2656	following macros are defined:
…		…
2661		2661
2662	This provides the loop I<argument> for functions, if one is required ("ev	2662	This provides the loop I<argument> for functions, if one is required ("ev
2663	loop argument"). The C<EV_A> form is used when this is the sole argument,	2663	loop argument"). The C<EV_A> form is used when this is the sole argument,
2664	C<EV_A_> is used when other arguments are following. Example:	2664	C<EV_A_> is used when other arguments are following. Example:
2665		2665
2666	ev_unref (EV_A);	2666	ev_unref (EV_A);
2667	ev_timer_add (EV_A_ watcher);	2667	ev_timer_add (EV_A_ watcher);
2668	ev_loop (EV_A_ 0);	2668	ev_loop (EV_A_ 0);
2669		2669
2670	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	2670	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
2671	which is often provided by the following macro.	2671	which is often provided by the following macro.
2672		2672
2673	=item C<EV_P>, C<EV_P_>	2673	=item C<EV_P>, C<EV_P_>
2674		2674
2675	This provides the loop I<parameter> for functions, if one is required ("ev	2675	This provides the loop I<parameter> for functions, if one is required ("ev
2676	loop parameter"). The C<EV_P> form is used when this is the sole parameter,	2676	loop parameter"). The C<EV_P> form is used when this is the sole parameter,
2677	C<EV_P_> is used when other parameters are following. Example:	2677	C<EV_P_> is used when other parameters are following. Example:
2678		2678
2679	// this is how ev_unref is being declared	2679	// this is how ev_unref is being declared
2680	static void ev_unref (EV_P);	2680	static void ev_unref (EV_P);
2681		2681
2682	// this is how you can declare your typical callback	2682	// this is how you can declare your typical callback
2683	static void cb (EV_P_ ev_timer *w, int revents)	2683	static void cb (EV_P_ ev_timer *w, int revents)
2684		2684
2685	It declares a parameter C<loop> of type C<struct ev_loop *>, quite	2685	It declares a parameter C<loop> of type C<struct ev_loop *>, quite
2686	suitable for use with C<EV_A>.	2686	suitable for use with C<EV_A>.
2687		2687
2688	=item C<EV_DEFAULT>, C<EV_DEFAULT_>	2688	=item C<EV_DEFAULT>, C<EV_DEFAULT_>
…		…
2704		2704
2705	Example: Declare and initialise a check watcher, utilising the above	2705	Example: Declare and initialise a check watcher, utilising the above
2706	macros so it will work regardless of whether multiple loops are supported	2706	macros so it will work regardless of whether multiple loops are supported
2707	or not.	2707	or not.
2708		2708
2709	static void	2709	static void
2710	check_cb (EV_P_ ev_timer *w, int revents)	2710	check_cb (EV_P_ ev_timer *w, int revents)
2711	{	2711	{
2712	ev_check_stop (EV_A_ w);	2712	ev_check_stop (EV_A_ w);
2713	}	2713	}
2714		2714
2715	ev_check check;	2715	ev_check check;
2716	ev_check_init (&check, check_cb);	2716	ev_check_init (&check, check_cb);
2717	ev_check_start (EV_DEFAULT_ &check);	2717	ev_check_start (EV_DEFAULT_ &check);
2718	ev_loop (EV_DEFAULT_ 0);	2718	ev_loop (EV_DEFAULT_ 0);
2719		2719
2720	=head1 EMBEDDING	2720	=head1 EMBEDDING
2721		2721
2722	Libev can (and often is) directly embedded into host	2722	Libev can (and often is) directly embedded into host
2723	applications. Examples of applications that embed it include the Deliantra	2723	applications. Examples of applications that embed it include the Deliantra
…		…
2730	libev somewhere in your source tree).	2730	libev somewhere in your source tree).
2731		2731
2732	=head2 FILESETS	2732	=head2 FILESETS
2733		2733
2734	Depending on what features you need you need to include one or more sets of files	2734	Depending on what features you need you need to include one or more sets of files
2735	in your app.	2735	in your application.
2736		2736
2737	=head3 CORE EVENT LOOP	2737	=head3 CORE EVENT LOOP
2738		2738
2739	To include only the libev core (all the C<ev_*> functions), with manual	2739	To include only the libev core (all the C<ev_*> functions), with manual
2740	configuration (no autoconf):	2740	configuration (no autoconf):
2741		2741
2742	#define EV_STANDALONE 1	2742	#define EV_STANDALONE 1
2743	#include "ev.c"	2743	#include "ev.c"
2744		2744
2745	This will automatically include F<ev.h>, too, and should be done in a	2745	This will automatically include F<ev.h>, too, and should be done in a
2746	single C source file only to provide the function implementations. To use	2746	single C source file only to provide the function implementations. To use
2747	it, do the same for F<ev.h> in all files wishing to use this API (best	2747	it, do the same for F<ev.h> in all files wishing to use this API (best
2748	done by writing a wrapper around F<ev.h> that you can include instead and	2748	done by writing a wrapper around F<ev.h> that you can include instead and
2749	where you can put other configuration options):	2749	where you can put other configuration options):
2750		2750
2751	#define EV_STANDALONE 1	2751	#define EV_STANDALONE 1
2752	#include "ev.h"	2752	#include "ev.h"
2753		2753
2754	Both header files and implementation files can be compiled with a C++	2754	Both header files and implementation files can be compiled with a C++
2755	compiler (at least, thats a stated goal, and breakage will be treated	2755	compiler (at least, thats a stated goal, and breakage will be treated
2756	as a bug).	2756	as a bug).
2757		2757
2758	You need the following files in your source tree, or in a directory	2758	You need the following files in your source tree, or in a directory
2759	in your include path (e.g. in libev/ when using -Ilibev):	2759	in your include path (e.g. in libev/ when using -Ilibev):
2760		2760
2761	ev.h	2761	ev.h
2762	ev.c	2762	ev.c
2763	ev_vars.h	2763	ev_vars.h
2764	ev_wrap.h	2764	ev_wrap.h
2765		2765
2766	ev_win32.c required on win32 platforms only	2766	ev_win32.c required on win32 platforms only
2767		2767
2768	ev_select.c only when select backend is enabled (which is enabled by default)	2768	ev_select.c only when select backend is enabled (which is enabled by default)
2769	ev_poll.c only when poll backend is enabled (disabled by default)	2769	ev_poll.c only when poll backend is enabled (disabled by default)
2770	ev_epoll.c only when the epoll backend is enabled (disabled by default)	2770	ev_epoll.c only when the epoll backend is enabled (disabled by default)
2771	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)	2771	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
2772	ev_port.c only when the solaris port backend is enabled (disabled by default)	2772	ev_port.c only when the solaris port backend is enabled (disabled by default)
2773		2773
2774	F<ev.c> includes the backend files directly when enabled, so you only need	2774	F<ev.c> includes the backend files directly when enabled, so you only need
2775	to compile this single file.	2775	to compile this single file.
2776		2776
2777	=head3 LIBEVENT COMPATIBILITY API	2777	=head3 LIBEVENT COMPATIBILITY API
2778		2778
2779	To include the libevent compatibility API, also include:	2779	To include the libevent compatibility API, also include:
2780		2780
2781	#include "event.c"	2781	#include "event.c"
2782		2782
2783	in the file including F<ev.c>, and:	2783	in the file including F<ev.c>, and:
2784		2784
2785	#include "event.h"	2785	#include "event.h"
2786		2786
2787	in the files that want to use the libevent API. This also includes F<ev.h>.	2787	in the files that want to use the libevent API. This also includes F<ev.h>.
2788		2788
2789	You need the following additional files for this:	2789	You need the following additional files for this:
2790		2790
2791	event.h	2791	event.h
2792	event.c	2792	event.c
2793		2793
2794	=head3 AUTOCONF SUPPORT	2794	=head3 AUTOCONF SUPPORT
2795		2795
2796	Instead of using C<EV_STANDALONE=1> and providing your config in	2796	Instead of using C<EV_STANDALONE=1> and providing your configuration in
2797	whatever way you want, you can also C<m4_include([libev.m4])> in your	2797	whatever way you want, you can also C<m4_include([libev.m4])> in your
2798	F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then	2798	F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then
2799	include F<config.h> and configure itself accordingly.	2799	include F<config.h> and configure itself accordingly.
2800		2800
2801	For this of course you need the m4 file:	2801	For this of course you need the m4 file:
2802		2802
2803	libev.m4	2803	libev.m4
2804		2804
2805	=head2 PREPROCESSOR SYMBOLS/MACROS	2805	=head2 PREPROCESSOR SYMBOLS/MACROS
2806		2806
2807	Libev can be configured via a variety of preprocessor symbols you have to	2807	Libev can be configured via a variety of preprocessor symbols you have to
2808	define before including any of its files. The default in the absense of	2808	define before including any of its files. The default in the absence of
2809	autoconf is noted for every option.	2809	autoconf is noted for every option.
2810		2810
2811	=over 4	2811	=over 4
2812		2812
2813	=item EV_STANDALONE	2813	=item EV_STANDALONE
…		…
2819	F<event.h> that are not directly supported by the libev core alone.	2819	F<event.h> that are not directly supported by the libev core alone.
2820		2820
2821	=item EV_USE_MONOTONIC	2821	=item EV_USE_MONOTONIC
2822		2822
2823	If defined to be C<1>, libev will try to detect the availability of the	2823	If defined to be C<1>, libev will try to detect the availability of the
2824	monotonic clock option at both compiletime and runtime. Otherwise no use	2824	monotonic clock option at both compile time and runtime. Otherwise no use
2825	of the monotonic clock option will be attempted. If you enable this, you	2825	of the monotonic clock option will be attempted. If you enable this, you
2826	usually have to link against librt or something similar. Enabling it when	2826	usually have to link against librt or something similar. Enabling it when
2827	the functionality isn't available is safe, though, although you have	2827	the functionality isn't available is safe, though, although you have
2828	to make sure you link against any libraries where the C<clock_gettime>	2828	to make sure you link against any libraries where the C<clock_gettime>
2829	function is hiding in (often F<-lrt>).	2829	function is hiding in (often F<-lrt>).
2830		2830
2831	=item EV_USE_REALTIME	2831	=item EV_USE_REALTIME
2832		2832
2833	If defined to be C<1>, libev will try to detect the availability of the	2833	If defined to be C<1>, libev will try to detect the availability of the
2834	realtime clock option at compiletime (and assume its availability at	2834	real-time clock option at compile time (and assume its availability at
2835	runtime if successful). Otherwise no use of the realtime clock option will	2835	runtime if successful). Otherwise no use of the real-time clock option will
2836	be attempted. This effectively replaces C<gettimeofday> by C<clock_get	2836	be attempted. This effectively replaces C<gettimeofday> by C<clock_get
2837	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the	2837	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
2838	note about libraries in the description of C<EV_USE_MONOTONIC>, though.	2838	note about libraries in the description of C<EV_USE_MONOTONIC>, though.
2839		2839
2840	=item EV_USE_NANOSLEEP	2840	=item EV_USE_NANOSLEEP
…		…
2851	2.7 or newer, otherwise disabled.	2851	2.7 or newer, otherwise disabled.
2852		2852
2853	=item EV_USE_SELECT	2853	=item EV_USE_SELECT
2854		2854
2855	If undefined or defined to be C<1>, libev will compile in support for the	2855	If undefined or defined to be C<1>, libev will compile in support for the
2856	C<select>(2) backend. No attempt at autodetection will be done: if no	2856	C<select>(2) backend. No attempt at auto-detection will be done: if no
2857	other method takes over, select will be it. Otherwise the select backend	2857	other method takes over, select will be it. Otherwise the select backend
2858	will not be compiled in.	2858	will not be compiled in.
2859		2859
2860	=item EV_SELECT_USE_FD_SET	2860	=item EV_SELECT_USE_FD_SET
2861		2861
2862	If defined to C<1>, then the select backend will use the system C<fd_set>	2862	If defined to C<1>, then the select backend will use the system C<fd_set>
2863	structure. This is useful if libev doesn't compile due to a missing	2863	structure. This is useful if libev doesn't compile due to a missing
2864	C<NFDBITS> or C<fd_mask> definition or it misguesses the bitset layout on	2864	C<NFDBITS> or C<fd_mask> definition or it mis-guesses the bitset layout on
2865	exotic systems. This usually limits the range of file descriptors to some	2865	exotic systems. This usually limits the range of file descriptors to some
2866	low limit such as 1024 or might have other limitations (winsocket only	2866	low limit such as 1024 or might have other limitations (winsocket only
2867	allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation, might	2867	allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation, might
2868	influence the size of the C<fd_set> used.	2868	influence the size of the C<fd_set> used.
2869		2869
…		…
2918	otherwise another method will be used as fallback. This is the preferred	2918	otherwise another method will be used as fallback. This is the preferred
2919	backend for Solaris 10 systems.	2919	backend for Solaris 10 systems.
2920		2920
2921	=item EV_USE_DEVPOLL	2921	=item EV_USE_DEVPOLL
2922		2922
2923	reserved for future expansion, works like the USE symbols above.	2923	Reserved for future expansion, works like the USE symbols above.
2924		2924
2925	=item EV_USE_INOTIFY	2925	=item EV_USE_INOTIFY
2926		2926
2927	If defined to be C<1>, libev will compile in support for the Linux inotify	2927	If defined to be C<1>, libev will compile in support for the Linux inotify
2928	interface to speed up C<ev_stat> watchers. Its actual availability will	2928	interface to speed up C<ev_stat> watchers. Its actual availability will
…		…
2935	access is atomic with respect to other threads or signal contexts. No such	2935	access is atomic with respect to other threads or signal contexts. No such
2936	type is easily found in the C language, so you can provide your own type	2936	type is easily found in the C language, so you can provide your own type
2937	that you know is safe for your purposes. It is used both for signal handler "locking"	2937	that you know is safe for your purposes. It is used both for signal handler "locking"
2938	as well as for signal and thread safety in C<ev_async> watchers.	2938	as well as for signal and thread safety in C<ev_async> watchers.
2939		2939
2940	In the absense of this define, libev will use C<sig_atomic_t volatile>	2940	In the absence of this define, libev will use C<sig_atomic_t volatile>
2941	(from F<signal.h>), which is usually good enough on most platforms.	2941	(from F<signal.h>), which is usually good enough on most platforms.
2942		2942
2943	=item EV_H	2943	=item EV_H
2944		2944
2945	The name of the F<ev.h> header file used to include it. The default if	2945	The name of the F<ev.h> header file used to include it. The default if
…		…
2984	When doing priority-based operations, libev usually has to linearly search	2984	When doing priority-based operations, libev usually has to linearly search
2985	all the priorities, so having many of them (hundreds) uses a lot of space	2985	all the priorities, so having many of them (hundreds) uses a lot of space
2986	and time, so using the defaults of five priorities (-2 .. +2) is usually	2986	and time, so using the defaults of five priorities (-2 .. +2) is usually
2987	fine.	2987	fine.
2988		2988
2989	If your embedding app does not need any priorities, defining these both to	2989	If your embedding application does not need any priorities, defining these both to
2990	C<0> will save some memory and cpu.	2990	C<0> will save some memory and CPU.
2991		2991
2992	=item EV_PERIODIC_ENABLE	2992	=item EV_PERIODIC_ENABLE
2993		2993
2994	If undefined or defined to be C<1>, then periodic timers are supported. If	2994	If undefined or defined to be C<1>, then periodic timers are supported. If
2995	defined to be C<0>, then they are not. Disabling them saves a few kB of	2995	defined to be C<0>, then they are not. Disabling them saves a few kB of
…		…
3023		3023
3024	=item EV_MINIMAL	3024	=item EV_MINIMAL
3025		3025
3026	If you need to shave off some kilobytes of code at the expense of some	3026	If you need to shave off some kilobytes of code at the expense of some
3027	speed, define this symbol to C<1>. Currently this is used to override some	3027	speed, define this symbol to C<1>. Currently this is used to override some
3028	inlining decisions, saves roughly 30% codesize of amd64. It also selects a	3028	inlining decisions, saves roughly 30% code size on amd64. It also selects a
3029	much smaller 2-heap for timer management over the default 4-heap.	3029	much smaller 2-heap for timer management over the default 4-heap.
3030		3030
3031	=item EV_PID_HASHSIZE	3031	=item EV_PID_HASHSIZE
3032		3032
3033	C<ev_child> watchers use a small hash table to distribute workload by	3033	C<ev_child> watchers use a small hash table to distribute workload by
…		…
3046	=item EV_USE_4HEAP	3046	=item EV_USE_4HEAP
3047		3047
3048	Heaps are not very cache-efficient. To improve the cache-efficiency of the	3048	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3049	timer and periodics heap, libev uses a 4-heap when this symbol is defined	3049	timer and periodics heap, libev uses a 4-heap when this symbol is defined
3050	to C<1>. The 4-heap uses more complicated (longer) code but has	3050	to C<1>. The 4-heap uses more complicated (longer) code but has
3051	noticably faster performance with many (thousands) of watchers.	3051	noticeably faster performance with many (thousands) of watchers.
3052		3052
3053	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	3053	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>
3054	(disabled).	3054	(disabled).
3055		3055
3056	=item EV_HEAP_CACHE_AT	3056	=item EV_HEAP_CACHE_AT
…		…
3058	Heaps are not very cache-efficient. To improve the cache-efficiency of the	3058	Heaps are not very cache-efficient. To improve the cache-efficiency of the
3059	timer and periodics heap, libev can cache the timestamp (I<at>) within	3059	timer and periodics heap, libev can cache the timestamp (I<at>) within
3060	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),	3060	the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
3061	which uses 8-12 bytes more per watcher and a few hundred bytes more code,	3061	which uses 8-12 bytes more per watcher and a few hundred bytes more code,
3062	but avoids random read accesses on heap changes. This improves performance	3062	but avoids random read accesses on heap changes. This improves performance
3063	noticably with with many (hundreds) of watchers.	3063	noticeably with with many (hundreds) of watchers.
3064		3064
3065	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	3065	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>
3066	(disabled).	3066	(disabled).
3067		3067
3068	=item EV_VERIFY	3068	=item EV_VERIFY
…		…
3085	members. You have to define it each time you include one of the files,	3085	members. You have to define it each time you include one of the files,
3086	though, and it must be identical each time.	3086	though, and it must be identical each time.
3087		3087
3088	For example, the perl EV module uses something like this:	3088	For example, the perl EV module uses something like this:
3089		3089
3090	#define EV_COMMON \	3090	#define EV_COMMON \
3091	SV *self; /* contains this struct */ \	3091	SV *self; /* contains this struct */ \
3092	SV *cb_sv, *fh /* note no trailing ";" */	3092	SV *cb_sv, *fh /* note no trailing ";" */
3093		3093
3094	=item EV_CB_DECLARE (type)	3094	=item EV_CB_DECLARE (type)
3095		3095
3096	=item EV_CB_INVOKE (watcher, revents)	3096	=item EV_CB_INVOKE (watcher, revents)
3097		3097
…		…
3104	avoid the C<struct ev_loop *> as first argument in all cases, or to use	3104	avoid the C<struct ev_loop *> as first argument in all cases, or to use
3105	method calls instead of plain function calls in C++.	3105	method calls instead of plain function calls in C++.
3106		3106
3107	=head2 EXPORTED API SYMBOLS	3107	=head2 EXPORTED API SYMBOLS
3108		3108
3109	If you need to re-export the API (e.g. via a dll) and you need a list of	3109	If you need to re-export the API (e.g. via a DLL) and you need a list of
3110	exported symbols, you can use the provided F<Symbol.*> files which list	3110	exported symbols, you can use the provided F<Symbol.*> files which list
3111	all public symbols, one per line:	3111	all public symbols, one per line:
3112		3112
3113	Symbols.ev for libev proper	3113	Symbols.ev for libev proper
3114	Symbols.event for the libevent emulation	3114	Symbols.event for the libevent emulation
3115		3115
3116	This can also be used to rename all public symbols to avoid clashes with	3116	This can also be used to rename all public symbols to avoid clashes with
3117	multiple versions of libev linked together (which is obviously bad in	3117	multiple versions of libev linked together (which is obviously bad in
3118	itself, but sometimes it is inconvinient to avoid this).	3118	itself, but sometimes it is inconvenient to avoid this).
3119		3119
3120	A sed command like this will create wrapper C<#define>'s that you need to	3120	A sed command like this will create wrapper C<#define>'s that you need to
3121	include before including F<ev.h>:	3121	include before including F<ev.h>:
3122		3122
3123	<Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h	3123	<Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h
…		…
3140	file.	3140	file.
3141		3141
3142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	3142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
3143	that everybody includes and which overrides some configure choices:	3143	that everybody includes and which overrides some configure choices:
3144		3144
3145	#define EV_MINIMAL 1	3145	#define EV_MINIMAL 1
3146	#define EV_USE_POLL 0	3146	#define EV_USE_POLL 0
3147	#define EV_MULTIPLICITY 0	3147	#define EV_MULTIPLICITY 0
3148	#define EV_PERIODIC_ENABLE 0	3148	#define EV_PERIODIC_ENABLE 0
3149	#define EV_STAT_ENABLE 0	3149	#define EV_STAT_ENABLE 0
3150	#define EV_FORK_ENABLE 0	3150	#define EV_FORK_ENABLE 0
3151	#define EV_CONFIG_H <config.h>	3151	#define EV_CONFIG_H <config.h>
3152	#define EV_MINPRI 0	3152	#define EV_MINPRI 0
3153	#define EV_MAXPRI 0	3153	#define EV_MAXPRI 0
3154		3154
3155	#include "ev++.h"	3155	#include "ev++.h"
3156		3156
3157	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	3157	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3158		3158
3159	#include "ev_cpp.h"	3159	#include "ev_cpp.h"
3160	#include "ev.c"	3160	#include "ev.c"
3161		3161
3162		3162
3163	=head1 THREADS AND COROUTINES	3163	=head1 THREADS AND COROUTINES
3164		3164
3165	=head2 THREADS	3165	=head2 THREADS
3166		3166
3167	Libev itself is completely threadsafe, but it uses no locking. This	3167	Libev itself is completely thread-safe, but it uses no locking. This
3168	means that you can use as many loops as you want in parallel, as long as	3168	means that you can use as many loops as you want in parallel, as long as
3169	only one thread ever calls into one libev function with the same loop	3169	only one thread ever calls into one libev function with the same loop
3170	parameter.	3170	parameter.
3171		3171
3172	Or put differently: calls with different loop parameters can be done in	3172	Or put differently: calls with different loop parameters can be done in
…		…
3179	help you but by giving some generic advice:	3179	help you but by giving some generic advice:
3180		3180
3181	=over 4	3181	=over 4
3182		3182
3183	=item * most applications have a main thread: use the default libev loop	3183	=item * most applications have a main thread: use the default libev loop
3184	in that thread, or create a seperate thread running only the default loop.	3184	in that thread, or create a separate thread running only the default loop.
3185		3185
3186	This helps integrating other libraries or software modules that use libev	3186	This helps integrating other libraries or software modules that use libev
3187	themselves and don't care/know about threading.	3187	themselves and don't care/know about threading.
3188		3188
3189	=item * one loop per thread is usually a good model.	3189	=item * one loop per thread is usually a good model.
3190		3190
3191	Doing this is almost never wrong, sometimes a better-performance model	3191	Doing this is almost never wrong, sometimes a better-performance model
3192	exists, but it is always a good start.	3192	exists, but it is always a good start.
3193		3193
3194	=item * other models exist, such as the leader/follower pattern, where one	3194	=item * other models exist, such as the leader/follower pattern, where one
3195	loop is handed through multiple threads in a kind of round-robbin fashion.	3195	loop is handed through multiple threads in a kind of round-robin fashion.
3196		3196
3197	Chosing a model is hard - look around, learn, know that usually you cna do	3197	Choosing a model is hard - look around, learn, know that usually you can do
3198	better than you currently do :-)	3198	better than you currently do :-)
3199		3199
3200	=item * often you need to talk to some other thread which blocks in the	3200	=item * often you need to talk to some other thread which blocks in the
3201	event loop - C<ev_async> watchers can be used to wake them up from other	3201	event loop - C<ev_async> watchers can be used to wake them up from other
3202	threads safely (or from signal contexts...).	3202	threads safely (or from signal contexts...).
3203		3203
3204	=back	3204	=back
3205		3205
3206	=head2 COROUTINES	3206	=head2 COROUTINES
3207		3207
3208	Libev is much more accomodating to coroutines ("cooperative threads"):	3208	Libev is much more accommodating to coroutines ("cooperative threads"):
3209	libev fully supports nesting calls to it's functions from different	3209	libev fully supports nesting calls to it's functions from different
3210	coroutines (e.g. you can call C<ev_loop> on the same loop from two	3210	coroutines (e.g. you can call C<ev_loop> on the same loop from two
3211	different coroutines and switch freely between both coroutines running the	3211	different coroutines and switch freely between both coroutines running the
3212	loop, as long as you don't confuse yourself). The only exception is that	3212	loop, as long as you don't confuse yourself). The only exception is that
3213	you must not do this from C<ev_periodic> reschedule callbacks.	3213	you must not do this from C<ev_periodic> reschedule callbacks.
…		…
3261		3261
3262	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	3262	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
3263		3263
3264	A change means an I/O watcher gets started or stopped, which requires	3264	A change means an I/O watcher gets started or stopped, which requires
3265	libev to recalculate its status (and possibly tell the kernel, depending	3265	libev to recalculate its status (and possibly tell the kernel, depending
3266	on backend and wether C<ev_io_set> was used).	3266	on backend and whether C<ev_io_set> was used).
3267		3267
3268	=item Activating one watcher (putting it into the pending state): O(1)	3268	=item Activating one watcher (putting it into the pending state): O(1)
3269		3269
3270	=item Priority handling: O(number_of_priorities)	3270	=item Priority handling: O(number_of_priorities)
3271		3271
…		…
3278		3278
3279	=item Processing ev_async_send: O(number_of_async_watchers)	3279	=item Processing ev_async_send: O(number_of_async_watchers)
3280		3280
3281	=item Processing signals: O(max_signal_number)	3281	=item Processing signals: O(max_signal_number)
3282		3282
3283	Sending involves a syscall I<iff> there were no other C<ev_async_send>	3283	Sending involves a system call I<iff> there were no other C<ev_async_send>
3284	calls in the current loop iteration. Checking for async and signal events	3284	calls in the current loop iteration. Checking for async and signal events
3285	involves iterating over all running async watchers or all signal numbers.	3285	involves iterating over all running async watchers or all signal numbers.
3286		3286
3287	=back	3287	=back
3288		3288
3289		3289
3290	=head1 Win32 platform limitations and workarounds	3290	=head1 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
3291		3291
3292	Win32 doesn't support any of the standards (e.g. POSIX) that libev	3292	Win32 doesn't support any of the standards (e.g. POSIX) that libev
3293	requires, and its I/O model is fundamentally incompatible with the POSIX	3293	requires, and its I/O model is fundamentally incompatible with the POSIX
3294	model. Libev still offers limited functionality on this platform in	3294	model. Libev still offers limited functionality on this platform in
3295	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	3295	the form of the C<EVBACKEND_SELECT> backend, and only supports socket
…		…
3302	way (note also that glib is the slowest event library known to man).	3302	way (note also that glib is the slowest event library known to man).
3303		3303
3304	There is no supported compilation method available on windows except	3304	There is no supported compilation method available on windows except
3305	embedding it into other applications.	3305	embedding it into other applications.
3306		3306
		3307	Not a libev limitation but worth mentioning: windows apparently doesn't
		3308	accept large writes: instead of resulting in a partial write, windows will
		3309	either accept everything or return C<ENOBUFS> if the buffer is too large,
		3310	so make sure you only write small amounts into your sockets (less than a
		3311	megabyte seems safe, but thsi apparently depends on the amount of memory
		3312	available).
		3313
3307	Due to the many, low, and arbitrary limits on the win32 platform and	3314	Due to the many, low, and arbitrary limits on the win32 platform and
3308	the abysmal performance of winsockets, using a large number of sockets	3315	the abysmal performance of winsockets, using a large number of sockets
3309	is not recommended (and not reasonable). If your program needs to use	3316	is not recommended (and not reasonable). If your program needs to use
3310	more than a hundred or so sockets, then likely it needs to use a totally	3317	more than a hundred or so sockets, then likely it needs to use a totally
3311	different implementation for windows, as libev offers the POSIX readiness	3318	different implementation for windows, as libev offers the POSIX readiness
3312	notification model, which cannot be implemented efficiently on windows	3319	notification model, which cannot be implemented efficiently on windows
3313	(microsoft monopoly games).	3320	(Microsoft monopoly games).
3314		3321
3315	=over 4	3322	=over 4
3316		3323
3317	=item The winsocket select function	3324	=item The winsocket select function
3318		3325
…		…
3321	also extremely buggy). This makes select very inefficient, and also	3328	also extremely buggy). This makes select very inefficient, and also
3322	requires a mapping from file descriptors to socket handles. See the	3329	requires a mapping from file descriptors to socket handles. See the
3323	discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and	3330	discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and
3324	C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.	3331	C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.
3325		3332
3326	The configuration for a "naked" win32 using the microsoft runtime	3333	The configuration for a "naked" win32 using the Microsoft runtime
3327	libraries and raw winsocket select is:	3334	libraries and raw winsocket select is:
3328		3335
3329	#define EV_USE_SELECT 1	3336	#define EV_USE_SELECT 1
3330	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	3337	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
3331		3338
3332	Note that winsockets handling of fd sets is O(n), so you can easily get a	3339	Note that winsockets handling of fd sets is O(n), so you can easily get a
3333	complexity in the O(n²) range when using win32.	3340	complexity in the O(n²) range when using win32.
3334		3341
3335	=item Limited number of file descriptors	3342	=item Limited number of file descriptors
3336		3343
3337	Windows has numerous arbitrary (and low) limits on things.	3344	Windows has numerous arbitrary (and low) limits on things.
3338		3345
3339	Early versions of winsocket's select only supported waiting for a maximum	3346	Early versions of winsocket's select only supported waiting for a maximum
3340	of C<64> handles (probably owning to the fact that all windows kernels	3347	of C<64> handles (probably owning to the fact that all windows kernels
3341	can only wait for C<64> things at the same time internally; microsoft	3348	can only wait for C<64> things at the same time internally; Microsoft
3342	recommends spawning a chain of threads and wait for 63 handles and the	3349	recommends spawning a chain of threads and wait for 63 handles and the
3343	previous thread in each. Great).	3350	previous thread in each. Great).
3344		3351
3345	Newer versions support more handles, but you need to define C<FD_SETSIZE>	3352	Newer versions support more handles, but you need to define C<FD_SETSIZE>
3346	to some high number (e.g. C<2048>) before compiling the winsocket select	3353	to some high number (e.g. C<2048>) before compiling the winsocket select
3347	call (which might be in libev or elsewhere, for example, perl does its own	3354	call (which might be in libev or elsewhere, for example, perl does its own
3348	select emulation on windows).	3355	select emulation on windows).
3349		3356
3350	Another limit is the number of file descriptors in the microsoft runtime	3357	Another limit is the number of file descriptors in the Microsoft runtime
3351	libraries, which by default is C<64> (there must be a hidden I<64> fetish	3358	libraries, which by default is C<64> (there must be a hidden I<64> fetish
3352	or something like this inside microsoft). You can increase this by calling	3359	or something like this inside Microsoft). You can increase this by calling
3353	C<_setmaxstdio>, which can increase this limit to C<2048> (another	3360	C<_setmaxstdio>, which can increase this limit to C<2048> (another
3354	arbitrary limit), but is broken in many versions of the microsoft runtime	3361	arbitrary limit), but is broken in many versions of the Microsoft runtime
3355	libraries.	3362	libraries.
3356		3363
3357	This might get you to about C<512> or C<2048> sockets (depending on	3364	This might get you to about C<512> or C<2048> sockets (depending on
3358	windows version and/or the phase of the moon). To get more, you need to	3365	windows version and/or the phase of the moon). To get more, you need to
3359	wrap all I/O functions and provide your own fd management, but the cost of	3366	wrap all I/O functions and provide your own fd management, but the cost of
…		…
3416	scared by this.	3423	scared by this.
3417		3424
3418	However, these are unavoidable for many reasons. For one, each compiler	3425	However, these are unavoidable for many reasons. For one, each compiler
3419	has different warnings, and each user has different tastes regarding	3426	has different warnings, and each user has different tastes regarding
3420	warning options. "Warn-free" code therefore cannot be a goal except when	3427	warning options. "Warn-free" code therefore cannot be a goal except when
3421	targetting a specific compiler and compiler-version.	3428	targeting a specific compiler and compiler-version.
3422		3429
3423	Another reason is that some compiler warnings require elaborate	3430	Another reason is that some compiler warnings require elaborate
3424	workarounds, or other changes to the code that make it less clear and less	3431	workarounds, or other changes to the code that make it less clear and less
3425	maintainable.	3432	maintainable.
3426		3433
3427	And of course, some compiler warnings are just plain stupid, or simply	3434	And of course, some compiler warnings are just plain stupid, or simply
3428	wrong (because they don't actually warn about the cindition their message	3435	wrong (because they don't actually warn about the condition their message
3429	seems to warn about).	3436	seems to warn about).
3430		3437
3431	While libev is written to generate as few warnings as possible,	3438	While libev is written to generate as few warnings as possible,
3432	"warn-free" code is not a goal, and it is recommended not to build libev	3439	"warn-free" code is not a goal, and it is recommended not to build libev
3433	with any compiler warnings enabled unless you are prepared to cope with	3440	with any compiler warnings enabled unless you are prepared to cope with
…		…
3445		3452
3446	==2274== definitely lost: 0 bytes in 0 blocks.	3453	==2274== definitely lost: 0 bytes in 0 blocks.
3447	==2274== possibly lost: 0 bytes in 0 blocks.	3454	==2274== possibly lost: 0 bytes in 0 blocks.
3448	==2274== still reachable: 256 bytes in 1 blocks.	3455	==2274== still reachable: 256 bytes in 1 blocks.
3449		3456
3450	then there is no memory leak. Similarly, under some circumstances,	3457	Then there is no memory leak. Similarly, under some circumstances,
3451	valgrind might report kernel bugs as if it were a bug in libev, or it	3458	valgrind might report kernel bugs as if it were a bug in libev, or it
3452	might be confused (it is a very good tool, but only a tool).	3459	might be confused (it is a very good tool, but only a tool).
3453		3460
3454	If you are unsure about something, feel free to contact the mailing list	3461	If you are unsure about something, feel free to contact the mailing list
3455	with the full valgrind report and an explanation on why you think this is	3462	with the full valgrind report and an explanation on why you think this is

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