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Revision 1.160 by root, Thu May 22 03:06:58 2008 UTC vs.
Revision 1.172 by root, Wed Aug 6 07:01:25 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.
604		604
605	Here are the gory details of what C<ev_loop> does:	605	Here are the gory details of what C<ev_loop> does:
606		606
607	- Before the first iteration, call any pending watchers.	607	- Before the first iteration, call any pending watchers.
608	* If EVFLAG_FORKCHECK was used, check for a fork.	608	* If EVFLAG_FORKCHECK was used, check for a fork.
609	- If a fork was detected, queue and call all fork watchers.	609	- If a fork was detected (by any means), queue and call all fork watchers.
610	- Queue and call all prepare watchers.	610	- Queue and call all prepare watchers.
611	- If we have been forked, recreate the kernel state.	611	- If we have been forked, detach and recreate the kernel state
		612	as to not disturb the other process.
612	- Update the kernel state with all outstanding changes.	613	- Update the kernel state with all outstanding changes.
613	- Update the "event loop time".	614	- Update the "event loop time" (ev_now ()).
614	- Calculate for how long to sleep or block, if at all	615	- Calculate for how long to sleep or block, if at all
615	(active idle watchers, EVLOOP_NONBLOCK or not having	616	(active idle watchers, EVLOOP_NONBLOCK or not having
616	any active watchers at all will result in not sleeping).	617	any active watchers at all will result in not sleeping).
617	- Sleep if the I/O and timer collect interval say so.	618	- Sleep if the I/O and timer collect interval say so.
618	- Block the process, waiting for any events.	619	- Block the process, waiting for any events.
619	- Queue all outstanding I/O (fd) events.	620	- Queue all outstanding I/O (fd) events.
620	- Update the "event loop time" and do time jump handling.	621	- Update the "event loop time" (ev_now ()), and do time jump adjustments.
621	- Queue all outstanding timers.	622	- Queue all outstanding timers.
622	- Queue all outstanding periodics.	623	- Queue all outstanding periodics.
623	- If no events are pending now, queue all idle watchers.	624	- Unless any events are pending now, queue all idle watchers.
624	- Queue all check watchers.	625	- Queue all check watchers.
625	- Call all queued watchers in reverse order (i.e. check watchers first).	626	- Call all queued watchers in reverse order (i.e. check watchers first).
626	Signals and child watchers are implemented as I/O watchers, and will	627	Signals and child watchers are implemented as I/O watchers, and will
627	be handled here by queueing them when their watcher gets executed.	628	be handled here by queueing them when their watcher gets executed.
628	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	629	- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
…		…
633	anymore.	634	anymore.
634		635
635	... queue jobs here, make sure they register event watchers as long	636	... queue jobs here, make sure they register event watchers as long
636	... as they still have work to do (even an idle watcher will do..)	637	... as they still have work to do (even an idle watcher will do..)
637	ev_loop (my_loop, 0);	638	ev_loop (my_loop, 0);
638	... jobs done. yeah!	639	... jobs done or somebody called unloop. yeah!
639		640
640	=item ev_unloop (loop, how)	641	=item ev_unloop (loop, how)
641		642
642	Can be used to make a call to C<ev_loop> return early (but only after it	643	Can be used to make a call to C<ev_loop> return early (but only after it
643	has processed all outstanding events). The C<how> argument must be either	644	has processed all outstanding events). The C<how> argument must be either
…		…
664	respectively).	665	respectively).
665		666
666	Example: Create a signal watcher, but keep it from keeping C<ev_loop>	667	Example: Create a signal watcher, but keep it from keeping C<ev_loop>
667	running when nothing else is active.	668	running when nothing else is active.
668		669
669	struct ev_signal exitsig;	670	struct ev_signal exitsig;
670	ev_signal_init (&exitsig, sig_cb, SIGINT);	671	ev_signal_init (&exitsig, sig_cb, SIGINT);
671	ev_signal_start (loop, &exitsig);	672	ev_signal_start (loop, &exitsig);
672	evf_unref (loop);	673	evf_unref (loop);
673		674
674	Example: For some weird reason, unregister the above signal handler again.	675	Example: For some weird reason, unregister the above signal handler again.
675		676
676	ev_ref (loop);	677	ev_ref (loop);
677	ev_signal_stop (loop, &exitsig);	678	ev_signal_stop (loop, &exitsig);
678		679
679	=item ev_set_io_collect_interval (loop, ev_tstamp interval)	680	=item ev_set_io_collect_interval (loop, ev_tstamp interval)
680		681
681	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)	682	=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
682		683
683	These advanced functions influence the time that libev will spend waiting	684	These advanced functions influence the time that libev will spend waiting
684	for events. Both are by default C<0>, meaning that libev will try to	685	for events. Both time intervals are by default C<0>, meaning that libev
685	invoke timer/periodic callbacks and I/O callbacks with minimum latency.	686	will try to invoke timer/periodic callbacks and I/O callbacks with minimum
		687	latency.
686		688
687	Setting these to a higher value (the C<interval> I<must> be >= C<0>)	689	Setting these to a higher value (the C<interval> I<must> be >= C<0>)
688	allows libev to delay invocation of I/O and timer/periodic callbacks to	690	allows libev to delay invocation of I/O and timer/periodic callbacks
689	increase efficiency of loop iterations.	691	to increase efficiency of loop iterations (or to increase power-saving
		692	opportunities).
690		693
691	The background is that sometimes your program runs just fast enough to	694	The background is that sometimes your program runs just fast enough to
692	handle one (or very few) event(s) per loop iteration. While this makes	695	handle one (or very few) event(s) per loop iteration. While this makes
693	the program responsive, it also wastes a lot of CPU time to poll for new	696	the program responsive, it also wastes a lot of CPU time to poll for new
694	events, especially with backends like C<select ()> which have a high	697	events, especially with backends like C<select ()> which have a high
…		…
704	to spend more time collecting timeouts, at the expense of increased	707	to spend more time collecting timeouts, at the expense of increased
705	latency (the watcher callback will be called later). C<ev_io> watchers	708	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	709	will not be affected. Setting this to a non-null value will not introduce
707	any overhead in libev.	710	any overhead in libev.
708		711
709	Many (busy) programs can usually benefit by setting the io collect	712	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	713	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	714	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>,	715	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.	716	as this approaches the timing granularity of most systems.
		717
		718	Setting the I<timeout collect interval> can improve the opportunity for
		719	saving power, as the program will "bundle" timer callback invocations that
		720	are "near" in time together, by delaying some, thus reducing the number of
		721	times the process sleeps and wakes up again. Another useful technique to
		722	reduce iterations/wake-ups is to use C<ev_periodic> watchers and make sure
		723	they fire on, say, one-second boundaries only.
714		724
715	=item ev_loop_verify (loop)	725	=item ev_loop_verify (loop)
716		726
717	This function only does something when C<EV_VERIFY> support has been	727	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	728	compiled in. It tries to go through all internal structures and checks
…		…
730		740
731	A watcher is a structure that you create and register to record your	741	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	742	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:	743	become readable, you would create an C<ev_io> watcher for that:
734		744
735	static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents)	745	static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents)
736	{	746	{
737	ev_io_stop (w);	747	ev_io_stop (w);
738	ev_unloop (loop, EVUNLOOP_ALL);	748	ev_unloop (loop, EVUNLOOP_ALL);
739	}	749	}
740		750
741	struct ev_loop *loop = ev_default_loop (0);	751	struct ev_loop *loop = ev_default_loop (0);
742	struct ev_io stdin_watcher;	752	struct ev_io stdin_watcher;
743	ev_init (&stdin_watcher, my_cb);	753	ev_init (&stdin_watcher, my_cb);
744	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);	754	ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
745	ev_io_start (loop, &stdin_watcher);	755	ev_io_start (loop, &stdin_watcher);
746	ev_loop (loop, 0);	756	ev_loop (loop, 0);
747		757
748	As you can see, you are responsible for allocating the memory for your	758	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,	759	watcher structures (and it is usually a bad idea to do this on the stack,
750	although this can sometimes be quite valid).	760	although this can sometimes be quite valid).
751		761
752	Each watcher structure must be initialised by a call to C<ev_init	762	Each watcher structure must be initialised by a call to C<ev_init
753	(watcher *, callback)>, which expects a callback to be provided. This	763	(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	764	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	765	watchers, each time the event loop detects that the file descriptor given
756	is readable and/or writable).	766	is readable and/or writable).
757		767
758	Each watcher type has its own C<< ev_<type>_set (watcher *, ...) >> macro	768	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	769	with arguments specific to this watcher type. There is also a macro
…		…
835		845
836	The given async watcher has been asynchronously notified (see C<ev_async>).	846	The given async watcher has been asynchronously notified (see C<ev_async>).
837		847
838	=item C<EV_ERROR>	848	=item C<EV_ERROR>
839		849
840	An unspecified error has occured, the watcher has been stopped. This might	850	An unspecified error has occurred, the watcher has been stopped. This might
841	happen because the watcher could not be properly started because libev	851	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	852	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	853	problem. You best act on it by reporting the problem and somehow coping
844	with the watcher being stopped.	854	with the watcher being stopped.
845		855
846	Libev will usually signal a few "dummy" events together with an error,	856	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	857	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	858	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	859	with the error from read() or write(). This will not work in multi-threaded
850	programs, though, so beware.	860	programs, though, so beware.
851		861
852	=back	862	=back
853		863
854	=head2 GENERIC WATCHER FUNCTIONS	864	=head2 GENERIC WATCHER FUNCTIONS
…		…
884	Although some watcher types do not have type-specific arguments	894	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.	895	(e.g. C<ev_prepare>) you still need to call its C<set> macro.
886		896
887	=item C<ev_TYPE_init> (ev_TYPE *watcher, callback, [args])	897	=item C<ev_TYPE_init> (ev_TYPE *watcher, callback, [args])
888		898
889	This convinience macro rolls both C<ev_init> and C<ev_TYPE_set> macro	899	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	900	calls into a single call. This is the most convenient method to initialise
891	a watcher. The same limitations apply, of course.	901	a watcher. The same limitations apply, of course.
892		902
893	=item C<ev_TYPE_start> (loop *, ev_TYPE *watcher)	903	=item C<ev_TYPE_start> (loop *, ev_TYPE *watcher)
894		904
895	Starts (activates) the given watcher. Only active watchers will receive	905	Starts (activates) the given watcher. Only active watchers will receive
…		…
978	to associate arbitrary data with your watcher. If you need more data and	988	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	989	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	990	member, you can also "subclass" the watcher type and provide your own
981	data:	991	data:
982		992
983	struct my_io	993	struct my_io
984	{	994	{
985	struct ev_io io;	995	struct ev_io io;
986	int otherfd;	996	int otherfd;
987	void *somedata;	997	void *somedata;
988	struct whatever *mostinteresting;	998	struct whatever *mostinteresting;
989	}	999	}
990		1000
991	And since your callback will be called with a pointer to the watcher, you	1001	And since your callback will be called with a pointer to the watcher, you
992	can cast it back to your own type:	1002	can cast it back to your own type:
993		1003
994	static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents)	1004	static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents)
995	{	1005	{
996	struct my_io *w = (struct my_io *)w_;	1006	struct my_io *w = (struct my_io *)w_;
997	...	1007	...
998	}	1008	}
999		1009
1000	More interesting and less C-conformant ways of casting your callback type	1010	More interesting and less C-conformant ways of casting your callback type
1001	instead have been omitted.	1011	instead have been omitted.
1002		1012
1003	Another common scenario is having some data structure with multiple	1013	Another common scenario is having some data structure with multiple
1004	watchers:	1014	watchers:
1005		1015
1006	struct my_biggy	1016	struct my_biggy
1007	{	1017	{
1008	int some_data;	1018	int some_data;
1009	ev_timer t1;	1019	ev_timer t1;
1010	ev_timer t2;	1020	ev_timer t2;
1011	}	1021	}
1012		1022
1013	In this case getting the pointer to C<my_biggy> is a bit more complicated,	1023	In this case getting the pointer to C<my_biggy> is a bit more complicated,
1014	you need to use C<offsetof>:	1024	you need to use C<offsetof>:
1015		1025
1016	#include <stddef.h>	1026	#include <stddef.h>
1017		1027
1018	static void	1028	static void
1019	t1_cb (EV_P_ struct ev_timer *w, int revents)	1029	t1_cb (EV_P_ struct ev_timer *w, int revents)
1020	{	1030	{
1021	struct my_biggy big = (struct my_biggy *	1031	struct my_biggy big = (struct my_biggy *
1022	(((char *)w) - offsetof (struct my_biggy, t1));	1032	(((char *)w) - offsetof (struct my_biggy, t1));
1023	}	1033	}
1024		1034
1025	static void	1035	static void
1026	t2_cb (EV_P_ struct ev_timer *w, int revents)	1036	t2_cb (EV_P_ struct ev_timer *w, int revents)
1027	{	1037	{
1028	struct my_biggy big = (struct my_biggy *	1038	struct my_biggy big = (struct my_biggy *
1029	(((char *)w) - offsetof (struct my_biggy, t2));	1039	(((char *)w) - offsetof (struct my_biggy, t2));
1030	}	1040	}
1031		1041
1032		1042
1033	=head1 WATCHER TYPES	1043	=head1 WATCHER TYPES
1034		1044
1035	This section describes each watcher in detail, but will not repeat	1045	This section describes each watcher in detail, but will not repeat
…		…
1067		1077
1068	Another thing you have to watch out for is that it is quite easy to	1078	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	1079	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	1080	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	1081	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	1082	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	1083	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	1084	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.	1085	C<EAGAIN> is far preferable to a program hanging until some data arrives.
1076		1086
1077	If you cannot run the fd in non-blocking mode (for example you should not	1087	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	1088	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	1089	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	1090	such as poll (fortunately in our Xlib example, Xlib already does this on
1081	its own, so its quite safe to use).	1091	its own, so its quite safe to use).
1082		1092
1083	=head3 The special problem of disappearing file descriptors	1093	=head3 The special problem of disappearing file descriptors
…		…
1143	=item ev_io_init (ev_io *, callback, int fd, int events)	1153	=item ev_io_init (ev_io *, callback, int fd, int events)
1144		1154
1145	=item ev_io_set (ev_io *, int fd, int events)	1155	=item ev_io_set (ev_io *, int fd, int events)
1146		1156
1147	Configures an C<ev_io> watcher. The C<fd> is the file descriptor to	1157	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	1158	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.	1159	C<EV_READ | EV_WRITE> to receive the given events.
1150		1160
1151	=item int fd [read-only]	1161	=item int fd [read-only]
1152		1162
1153	The file descriptor being watched.	1163	The file descriptor being watched.
…		…
1162		1172
1163	Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well	1173	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	1174	readable, but only once. Since it is likely line-buffered, you could
1165	attempt to read a whole line in the callback.	1175	attempt to read a whole line in the callback.
1166		1176
1167	static void	1177	static void
1168	stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)	1178	stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
1169	{	1179	{
1170	ev_io_stop (loop, w);	1180	ev_io_stop (loop, w);
1171	.. read from stdin here (or from w->fd) and haqndle any I/O errors	1181	.. read from stdin here (or from w->fd) and haqndle any I/O errors
1172	}	1182	}
1173		1183
1174	...	1184	...
1175	struct ev_loop *loop = ev_default_init (0);	1185	struct ev_loop *loop = ev_default_init (0);
1176	struct ev_io stdin_readable;	1186	struct ev_io stdin_readable;
1177	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);	1187	ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
1178	ev_io_start (loop, &stdin_readable);	1188	ev_io_start (loop, &stdin_readable);
1179	ev_loop (loop, 0);	1189	ev_loop (loop, 0);
1180		1190
1181		1191
1182	=head2 C<ev_timer> - relative and optionally repeating timeouts	1192	=head2 C<ev_timer> - relative and optionally repeating timeouts
1183		1193
1184	Timer watchers are simple relative timers that generate an event after a	1194	Timer watchers are simple relative timers that generate an event after a
1185	given time, and optionally repeating in regular intervals after that.	1195	given time, and optionally repeating in regular intervals after that.
1186		1196
1187	The timers are based on real time, that is, if you register an event that	1197	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	1198	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	1199	year, it will still time out after (roughly) and hour. "Roughly" because
1190	detecting time jumps is hard, and some inaccuracies are unavoidable (the	1200	detecting time jumps is hard, and some inaccuracies are unavoidable (the
1191	monotonic clock option helps a lot here).	1201	monotonic clock option helps a lot here).
1192		1202
1193	The relative timeouts are calculated relative to the C<ev_now ()>	1203	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	1206	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:	1207	on the current time, use something like this to adjust for this:
1198		1208
1199	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);	1209	ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);
1200		1210
1201	The callback is guarenteed to be invoked only after its timeout has passed,	1211	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	1212	but if multiple timers become ready during the same loop iteration then
1203	order of execution is undefined.	1213	order of execution is undefined.
1204		1214
1205	=head3 Watcher-Specific Functions and Data Members	1215	=head3 Watcher-Specific Functions and Data Members
1206		1216
…		…
1227	This will act as if the timer timed out and restart it again if it is	1237	This will act as if the timer timed out and restart it again if it is
1228	repeating. The exact semantics are:	1238	repeating. The exact semantics are:
1229		1239
1230	If the timer is pending, its pending status is cleared.	1240	If the timer is pending, its pending status is cleared.
1231		1241
1232	If the timer is started but nonrepeating, stop it (as if it timed out).	1242	If the timer is started but non-repeating, stop it (as if it timed out).
1233		1243
1234	If the timer is repeating, either start it if necessary (with the	1244	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.	1245	C<repeat> value), or reset the running timer to the C<repeat> value.
1236		1246
1237	This sounds a bit complicated, but here is a useful and typical	1247	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	1248	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	1249	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	1250	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	1251	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	1252	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	1253	you go into an idle state where you do not expect data to travel on the
…		…
1269		1279
1270	=head3 Examples	1280	=head3 Examples
1271		1281
1272	Example: Create a timer that fires after 60 seconds.	1282	Example: Create a timer that fires after 60 seconds.
1273		1283
1274	static void	1284	static void
1275	one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)	1285	one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
1276	{	1286	{
1277	.. one minute over, w is actually stopped right here	1287	.. one minute over, w is actually stopped right here
1278	}	1288	}
1279		1289
1280	struct ev_timer mytimer;	1290	struct ev_timer mytimer;
1281	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	1291	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1282	ev_timer_start (loop, &mytimer);	1292	ev_timer_start (loop, &mytimer);
1283		1293
1284	Example: Create a timeout timer that times out after 10 seconds of	1294	Example: Create a timeout timer that times out after 10 seconds of
1285	inactivity.	1295	inactivity.
1286		1296
1287	static void	1297	static void
1288	timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)	1298	timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
1289	{	1299	{
1290	.. ten seconds without any activity	1300	.. ten seconds without any activity
1291	}	1301	}
1292		1302
1293	struct ev_timer mytimer;	1303	struct ev_timer mytimer;
1294	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */	1304	ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
1295	ev_timer_again (&mytimer); /* start timer */	1305	ev_timer_again (&mytimer); /* start timer */
1296	ev_loop (loop, 0);	1306	ev_loop (loop, 0);
1297		1307
1298	// and in some piece of code that gets executed on any "activity":	1308	// and in some piece of code that gets executed on any "activity":
1299	// reset the timeout to start ticking again at 10 seconds	1309	// reset the timeout to start ticking again at 10 seconds
1300	ev_timer_again (&mytimer);	1310	ev_timer_again (&mytimer);
1301		1311
1302		1312
1303	=head2 C<ev_periodic> - to cron or not to cron?	1313	=head2 C<ev_periodic> - to cron or not to cron?
1304		1314
1305	Periodic watchers are also timers of a kind, but they are very versatile	1315	Periodic watchers are also timers of a kind, but they are very versatile
1306	(and unfortunately a bit complex).	1316	(and unfortunately a bit complex).
1307		1317
1308	Unlike C<ev_timer>'s, they are not based on real time (or relative time)	1318	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	1319	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	1320	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 ()	1321	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	1322	+ 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	1323	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	1324	to trigger the event (unlike an C<ev_timer>, which would still trigger
1315	roughly 10 seconds later as it uses a relative timeout).	1325	roughly 10 seconds later as it uses a relative timeout).
1316		1326
1317	C<ev_periodic>s can also be used to implement vastly more complex timers,	1327	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	1328	such as triggering an event on each "midnight, local time", or other
1319	complicated, rules.	1329	complicated, rules.
1320		1330
1321	As with timers, the callback is guarenteed to be invoked only when the	1331	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	1332	time (C<at>) has passed, but if multiple periodic timers become ready
1323	during the same loop iteration then order of execution is undefined.	1333	during the same loop iteration then order of execution is undefined.
1324		1334
1325	=head3 Watcher-Specific Functions and Data Members	1335	=head3 Watcher-Specific Functions and Data Members
1326		1336
…		…
1335		1345
1336	=over 4	1346	=over 4
1337		1347
1338	=item * absolute timer (at = time, interval = reschedule_cb = 0)	1348	=item * absolute timer (at = time, interval = reschedule_cb = 0)
1339		1349
1340	In this configuration the watcher triggers an event after the wallclock	1350	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	1351	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	1352	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.	1353	run when the system time reaches or surpasses this time.
1344		1354
1345	=item * repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)	1355	=item * repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)
…		…
1353	the hour:	1363	the hour:
1354		1364
1355	ev_periodic_set (&periodic, 0., 3600., 0);	1365	ev_periodic_set (&periodic, 0., 3600., 0);
1356		1366
1357	This doesn't mean there will always be 3600 seconds in between triggers,	1367	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	1368	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	1369	full hour (UTC), or more correctly, when the system time is evenly divisible
1360	by 3600.	1370	by 3600.
1361		1371
1362	Another way to think about it (for the mathematically inclined) is that	1372	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	1373	C<ev_periodic> will try to run the callback in this mode at the next possible
…		…
1365		1375
1366	For numerical stability it is preferable that the C<at> value is near	1376	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	1377	C<ev_now ()> (the current time), but there is no range requirement for
1368	this value, and in fact is often specified as zero.	1378	this value, and in fact is often specified as zero.
1369		1379
1370	Note also that there is an upper limit to how often a timer can fire (cpu	1380	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	1381	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	1382	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).	1383	millisecond (if the OS supports it and the machine is fast enough).
1374		1384
1375	=item * manual reschedule mode (at and interval ignored, reschedule_cb = callback)	1385	=item * manual reschedule mode (at and interval ignored, reschedule_cb = callback)
1376		1386
1377	In this mode the values for C<interval> and C<at> are both being	1387	In this mode the values for C<interval> and C<at> are both being
…		…
1446		1456
1447	=head3 Examples	1457	=head3 Examples
1448		1458
1449	Example: Call a callback every hour, or, more precisely, whenever the	1459	Example: Call a callback every hour, or, more precisely, whenever the
1450	system clock is divisible by 3600. The callback invocation times have	1460	system clock is divisible by 3600. The callback invocation times have
1451	potentially a lot of jittering, but good long-term stability.	1461	potentially a lot of jitter, but good long-term stability.
1452		1462
1453	static void	1463	static void
1454	clock_cb (struct ev_loop *loop, struct ev_io *w, int revents)	1464	clock_cb (struct ev_loop *loop, struct ev_io *w, int revents)
1455	{	1465	{
1456	... its now a full hour (UTC, or TAI or whatever your clock follows)	1466	... its now a full hour (UTC, or TAI or whatever your clock follows)
1457	}	1467	}
1458		1468
1459	struct ev_periodic hourly_tick;	1469	struct ev_periodic hourly_tick;
1460	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1470	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1461	ev_periodic_start (loop, &hourly_tick);	1471	ev_periodic_start (loop, &hourly_tick);
1462		1472
1463	Example: The same as above, but use a reschedule callback to do it:	1473	Example: The same as above, but use a reschedule callback to do it:
1464		1474
1465	#include <math.h>	1475	#include <math.h>
1466		1476
1467	static ev_tstamp	1477	static ev_tstamp
1468	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1478	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1469	{	1479	{
1470	return fmod (now, 3600.) + 3600.;	1480	return fmod (now, 3600.) + 3600.;
1471	}	1481	}
1472		1482
1473	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1483	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1474		1484
1475	Example: Call a callback every hour, starting now:	1485	Example: Call a callback every hour, starting now:
1476		1486
1477	struct ev_periodic hourly_tick;	1487	struct ev_periodic hourly_tick;
1478	ev_periodic_init (&hourly_tick, clock_cb,	1488	ev_periodic_init (&hourly_tick, clock_cb,
1479	fmod (ev_now (loop), 3600.), 3600., 0);	1489	fmod (ev_now (loop), 3600.), 3600., 0);
1480	ev_periodic_start (loop, &hourly_tick);	1490	ev_periodic_start (loop, &hourly_tick);
1481		1491
1482		1492
1483	=head2 C<ev_signal> - signal me when a signal gets signalled!	1493	=head2 C<ev_signal> - signal me when a signal gets signalled!
1484		1494
1485	Signal watchers will trigger an event when the process receives a specific	1495	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	1503	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	1504	watcher for a signal is stopped libev will reset the signal handler to
1495	SIG_DFL (regardless of what it was set to before).	1505	SIG_DFL (regardless of what it was set to before).
1496		1506
1497	If possible and supported, libev will install its handlers with	1507	If possible and supported, libev will install its handlers with
1498	C<SA_RESTART> behaviour enabled, so syscalls should not be unduly	1508	C<SA_RESTART> behaviour enabled, so system calls should not be unduly
1499	interrupted. If you have a problem with syscalls getting interrupted by	1509	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	1510	signals you can block all signals in an C<ev_check> watcher and unblock
1501	them in an C<ev_prepare> watcher.	1511	them in an C<ev_prepare> watcher.
1502		1512
1503	=head3 Watcher-Specific Functions and Data Members	1513	=head3 Watcher-Specific Functions and Data Members
1504		1514
…		…
1519		1529
1520	=head3 Examples	1530	=head3 Examples
1521		1531
1522	Example: Try to exit cleanly on SIGINT and SIGTERM.	1532	Example: Try to exit cleanly on SIGINT and SIGTERM.
1523		1533
1524	static void	1534	static void
1525	sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)	1535	sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
1526	{	1536	{
1527	ev_unloop (loop, EVUNLOOP_ALL);	1537	ev_unloop (loop, EVUNLOOP_ALL);
1528	}	1538	}
1529		1539
1530	struct ev_signal signal_watcher;	1540	struct ev_signal signal_watcher;
1531	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);	1541	ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1532	ev_signal_start (loop, &sigint_cb);	1542	ev_signal_start (loop, &sigint_cb);
1533		1543
1534		1544
1535	=head2 C<ev_child> - watch out for process status changes	1545	=head2 C<ev_child> - watch out for process status changes
1536		1546
1537	Child watchers trigger when your process receives a SIGCHLD in response to	1547	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	1549	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	1550	forked (which implies it might have already exited), as long as the event
1541	loop isn't entered (or is continued from a watcher).	1551	loop isn't entered (or is continued from a watcher).
1542		1552
1543	Only the default event loop is capable of handling signals, and therefore	1553	Only the default event loop is capable of handling signals, and therefore
1544	you can only rgeister child watchers in the default event loop.	1554	you can only register child watchers in the default event loop.
1545		1555
1546	=head3 Process Interaction	1556	=head3 Process Interaction
1547		1557
1548	Libev grabs C<SIGCHLD> as soon as the default event loop is	1558	Libev grabs C<SIGCHLD> as soon as the default event loop is
1549	initialised. This is necessary to guarantee proper behaviour even if	1559	initialised. This is necessary to guarantee proper behaviour even if
1550	the first child watcher is started after the child exits. The occurance	1560	the first child watcher is started after the child exits. The occurrence
1551	of C<SIGCHLD> is recorded asynchronously, but child reaping is done	1561	of C<SIGCHLD> is recorded asynchronously, but child reaping is done
1552	synchronously as part of the event loop processing. Libev always reaps all	1562	synchronously as part of the event loop processing. Libev always reaps all
1553	children, even ones not watched.	1563	children, even ones not watched.
1554		1564
1555	=head3 Overriding the Built-In Processing	1565	=head3 Overriding the Built-In Processing
…		…
1597	=head3 Examples	1607	=head3 Examples
1598		1608
1599	Example: C<fork()> a new process and install a child handler to wait for	1609	Example: C<fork()> a new process and install a child handler to wait for
1600	its completion.	1610	its completion.
1601		1611
1602	ev_child cw;	1612	ev_child cw;
1603		1613
1604	static void	1614	static void
1605	child_cb (EV_P_ struct ev_child *w, int revents)	1615	child_cb (EV_P_ struct ev_child *w, int revents)
1606	{	1616	{
1607	ev_child_stop (EV_A_ w);	1617	ev_child_stop (EV_A_ w);
1608	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);	1618	printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
1609	}	1619	}
1610		1620
1611	pid_t pid = fork ();	1621	pid_t pid = fork ();
1612		1622
1613	if (pid < 0)	1623	if (pid < 0)
1614	// error	1624	// error
1615	else if (pid == 0)	1625	else if (pid == 0)
1616	{	1626	{
1617	// the forked child executes here	1627	// the forked child executes here
1618	exit (1);	1628	exit (1);
1619	}	1629	}
1620	else	1630	else
1621	{	1631	{
1622	ev_child_init (&cw, child_cb, pid, 0);	1632	ev_child_init (&cw, child_cb, pid, 0);
1623	ev_child_start (EV_DEFAULT_ &cw);	1633	ev_child_start (EV_DEFAULT_ &cw);
1624	}	1634	}
1625		1635
1626		1636
1627	=head2 C<ev_stat> - did the file attributes just change?	1637	=head2 C<ev_stat> - did the file attributes just change?
1628		1638
1629	This watches a filesystem path for attribute changes. That is, it calls	1639	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	1640	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.	1641	compared to the last time, invoking the callback if it did.
1632		1642
1633	The path does not need to exist: changing from "path exists" to "path does	1643	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	1644	not exist" is a status change like any other. The condition "path does
…		…
1662	will be no polling.	1672	will be no polling.
1663		1673
1664	=head3 ABI Issues (Largefile Support)	1674	=head3 ABI Issues (Largefile Support)
1665		1675
1666	Libev by default (unless the user overrides this) uses the default	1676	Libev by default (unless the user overrides this) uses the default
1667	compilation environment, which means that on systems with optionally	1677	compilation environment, which means that on systems with large file
1668	disabled large file support, you get the 32 bit version of the stat	1678	support disabled by default, you get the 32 bit version of the stat
1669	structure. When using the library from programs that change the ABI to	1679	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	1680	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	1681	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	1682	obviously the case with any flags that change the ABI, but the problem is
1673	most noticably with ev_stat and largefile support.	1683	most noticeably disabled with ev_stat and large file support.
		1684
		1685	The solution for this is to lobby your distribution maker to make large
		1686	file interfaces available by default (as e.g. FreeBSD does) and not
		1687	optional. Libev cannot simply switch on large file support because it has
		1688	to exchange stat structures with application programs compiled using the
		1689	default compilation environment.
1674		1690
1675	=head3 Inotify	1691	=head3 Inotify
1676		1692
1677	When C<inotify (7)> support has been compiled into libev (generally only	1693	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	1694	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	1704	implement this functionality, due to the requirement of having a file
1689	descriptor open on the object at all times).	1705	descriptor open on the object at all times).
1690		1706
1691	=head3 The special problem of stat time resolution	1707	=head3 The special problem of stat time resolution
1692		1708
1693	The C<stat ()> syscall only supports full-second resolution portably, and	1709	The C<stat ()> system call only supports full-second resolution portably, and
1694	even on systems where the resolution is higher, many filesystems still	1710	even on systems where the resolution is higher, many file systems still
1695	only support whole seconds.	1711	only support whole seconds.
1696		1712
1697	That means that, if the time is the only thing that changes, you can	1713	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	1714	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	1715	calls your callback, which does something. When there is another update
…		…
1759		1775
1760	The specified interval.	1776	The specified interval.
1761		1777
1762	=item const char *path [read-only]	1778	=item const char *path [read-only]
1763		1779
1764	The filesystem path that is being watched.	1780	The file system path that is being watched.
1765		1781
1766	=back	1782	=back
1767		1783
1768	=head3 Examples	1784	=head3 Examples
1769		1785
1770	Example: Watch C</etc/passwd> for attribute changes.	1786	Example: Watch C</etc/passwd> for attribute changes.
1771		1787
1772	static void	1788	static void
1773	passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)	1789	passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
1774	{	1790	{
1775	/* /etc/passwd changed in some way */	1791	/* /etc/passwd changed in some way */
1776	if (w->attr.st_nlink)	1792	if (w->attr.st_nlink)
1777	{	1793	{
1778	printf ("passwd current size %ld\n", (long)w->attr.st_size);	1794	printf ("passwd current size %ld\n", (long)w->attr.st_size);
1779	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);	1795	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
1780	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);	1796	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
1781	}	1797	}
1782	else	1798	else
1783	/* you shalt not abuse printf for puts */	1799	/* you shalt not abuse printf for puts */
1784	puts ("wow, /etc/passwd is not there, expect problems. "	1800	puts ("wow, /etc/passwd is not there, expect problems. "
1785	"if this is windows, they already arrived\n");	1801	"if this is windows, they already arrived\n");
1786	}	1802	}
1787		1803
1788	...	1804	...
1789	ev_stat passwd;	1805	ev_stat passwd;
1790		1806
1791	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);	1807	ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
1792	ev_stat_start (loop, &passwd);	1808	ev_stat_start (loop, &passwd);
1793		1809
1794	Example: Like above, but additionally use a one-second delay so we do not	1810	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	1811	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	1812	one might do the work both on C<ev_stat> callback invocation I<and> on
1797	C<ev_timer> callback invocation).	1813	C<ev_timer> callback invocation).
1798		1814
1799	static ev_stat passwd;	1815	static ev_stat passwd;
1800	static ev_timer timer;	1816	static ev_timer timer;
1801		1817
1802	static void	1818	static void
1803	timer_cb (EV_P_ ev_timer *w, int revents)	1819	timer_cb (EV_P_ ev_timer *w, int revents)
1804	{	1820	{
1805	ev_timer_stop (EV_A_ w);	1821	ev_timer_stop (EV_A_ w);
1806		1822
1807	/* now it's one second after the most recent passwd change */	1823	/* now it's one second after the most recent passwd change */
1808	}	1824	}
1809		1825
1810	static void	1826	static void
1811	stat_cb (EV_P_ ev_stat *w, int revents)	1827	stat_cb (EV_P_ ev_stat *w, int revents)
1812	{	1828	{
1813	/* reset the one-second timer */	1829	/* reset the one-second timer */
1814	ev_timer_again (EV_A_ &timer);	1830	ev_timer_again (EV_A_ &timer);
1815	}	1831	}
1816		1832
1817	...	1833	...
1818	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);	1834	ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
1819	ev_stat_start (loop, &passwd);	1835	ev_stat_start (loop, &passwd);
1820	ev_timer_init (&timer, timer_cb, 0., 1.02);	1836	ev_timer_init (&timer, timer_cb, 0., 1.02);
1821		1837
1822		1838
1823	=head2 C<ev_idle> - when you've got nothing better to do...	1839	=head2 C<ev_idle> - when you've got nothing better to do...
1824		1840
1825	Idle watchers trigger events when no other events of the same or higher	1841	Idle watchers trigger events when no other events of the same or higher
…		…
1856	=head3 Examples	1872	=head3 Examples
1857		1873
1858	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the	1874	Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
1859	callback, free it. Also, use no error checking, as usual.	1875	callback, free it. Also, use no error checking, as usual.
1860		1876
1861	static void	1877	static void
1862	idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)	1878	idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
1863	{	1879	{
1864	free (w);	1880	free (w);
1865	// now do something you wanted to do when the program has	1881	// now do something you wanted to do when the program has
1866	// no longer anything immediate to do.	1882	// no longer anything immediate to do.
1867	}	1883	}
1868		1884
1869	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));	1885	struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1870	ev_idle_init (idle_watcher, idle_cb);	1886	ev_idle_init (idle_watcher, idle_cb);
1871	ev_idle_start (loop, idle_cb);	1887	ev_idle_start (loop, idle_cb);
1872		1888
1873		1889
1874	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!	1890	=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
1875		1891
1876	Prepare and check watchers are usually (but not always) used in tandem:	1892	Prepare and check watchers are usually (but not always) used in tandem:
…		…
1895		1911
1896	This is done by examining in each prepare call which file descriptors need	1912	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	1913	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	1914	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	1915	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	1916	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	1917	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,	1918	callbacks will never actually be called (but must be valid nevertheless,
1903	because you never know, you know?).	1919	because you never know, you know?).
1904		1920
1905	As another example, the Perl Coro module uses these hooks to integrate	1921	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	1964	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	1965	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	1966	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.	1967	the callbacks for the IO/timeout watchers might not have been called yet.
1952		1968
1953	static ev_io iow [nfd];	1969	static ev_io iow [nfd];
1954	static ev_timer tw;	1970	static ev_timer tw;
1955		1971
1956	static void	1972	static void
1957	io_cb (ev_loop *loop, ev_io *w, int revents)	1973	io_cb (ev_loop *loop, ev_io *w, int revents)
1958	{	1974	{
1959	}	1975	}
1960		1976
1961	// create io watchers for each fd and a timer before blocking	1977	// create io watchers for each fd and a timer before blocking
1962	static void	1978	static void
1963	adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)	1979	adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)
1964	{	1980	{
1965	int timeout = 3600000;	1981	int timeout = 3600000;
1966	struct pollfd fds [nfd];	1982	struct pollfd fds [nfd];
1967	// actual code will need to loop here and realloc etc.	1983	// actual code will need to loop here and realloc etc.
1968	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));	1984	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1969		1985
1970	/* the callback is illegal, but won't be called as we stop during check */	1986	/* the callback is illegal, but won't be called as we stop during check */
1971	ev_timer_init (&tw, 0, timeout * 1e-3);	1987	ev_timer_init (&tw, 0, timeout * 1e-3);
1972	ev_timer_start (loop, &tw);	1988	ev_timer_start (loop, &tw);
1973		1989
1974	// create one ev_io per pollfd	1990	// create one ev_io per pollfd
1975	for (int i = 0; i < nfd; ++i)	1991	for (int i = 0; i < nfd; ++i)
1976	{	1992	{
1977	ev_io_init (iow + i, io_cb, fds [i].fd,	1993	ev_io_init (iow + i, io_cb, fds [i].fd,
1978	((fds [i].events & POLLIN ? EV_READ : 0)	1994	((fds [i].events & POLLIN ? EV_READ : 0)
1979	| (fds [i].events & POLLOUT ? EV_WRITE : 0)));	1995	| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1980		1996
1981	fds [i].revents = 0;	1997	fds [i].revents = 0;
1982	ev_io_start (loop, iow + i);	1998	ev_io_start (loop, iow + i);
1983	}	1999	}
1984	}	2000	}
1985		2001
1986	// stop all watchers after blocking	2002	// stop all watchers after blocking
1987	static void	2003	static void
1988	adns_check_cb (ev_loop *loop, ev_check *w, int revents)	2004	adns_check_cb (ev_loop *loop, ev_check *w, int revents)
1989	{	2005	{
1990	ev_timer_stop (loop, &tw);	2006	ev_timer_stop (loop, &tw);
1991		2007
1992	for (int i = 0; i < nfd; ++i)	2008	for (int i = 0; i < nfd; ++i)
1993	{	2009	{
1994	// set the relevant poll flags	2010	// set the relevant poll flags
1995	// could also call adns_processreadable etc. here	2011	// could also call adns_processreadable etc. here
1996	struct pollfd *fd = fds + i;	2012	struct pollfd *fd = fds + i;
1997	int revents = ev_clear_pending (iow + i);	2013	int revents = ev_clear_pending (iow + i);
1998	if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;	2014	if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
1999	if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;	2015	if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
2000		2016
2001	// now stop the watcher	2017	// now stop the watcher
2002	ev_io_stop (loop, iow + i);	2018	ev_io_stop (loop, iow + i);
2003	}	2019	}
2004		2020
2005	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));	2021	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
2006	}	2022	}
2007		2023
2008	Method 2: This would be just like method 1, but you run C<adns_afterpoll>	2024	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.	2025	in the prepare watcher and would dispose of the check watcher.
2010		2026
2011	Method 3: If the module to be embedded supports explicit event	2027	Method 3: If the module to be embedded supports explicit event
2012	notification (adns does), you can also make use of the actual watcher	2028	notification (libadns does), you can also make use of the actual watcher
2013	callbacks, and only destroy/create the watchers in the prepare watcher.	2029	callbacks, and only destroy/create the watchers in the prepare watcher.
2014		2030
2015	static void	2031	static void
2016	timer_cb (EV_P_ ev_timer *w, int revents)	2032	timer_cb (EV_P_ ev_timer *w, int revents)
2017	{	2033	{
2018	adns_state ads = (adns_state)w->data;	2034	adns_state ads = (adns_state)w->data;
2019	update_now (EV_A);	2035	update_now (EV_A);
2020		2036
2021	adns_processtimeouts (ads, &tv_now);	2037	adns_processtimeouts (ads, &tv_now);
2022	}	2038	}
2023		2039
2024	static void	2040	static void
2025	io_cb (EV_P_ ev_io *w, int revents)	2041	io_cb (EV_P_ ev_io *w, int revents)
2026	{	2042	{
2027	adns_state ads = (adns_state)w->data;	2043	adns_state ads = (adns_state)w->data;
2028	update_now (EV_A);	2044	update_now (EV_A);
2029		2045
2030	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);	2046	if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
2031	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);	2047	if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
2032	}	2048	}
2033		2049
2034	// do not ever call adns_afterpoll	2050	// do not ever call adns_afterpoll
2035		2051
2036	Method 4: Do not use a prepare or check watcher because the module you	2052	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	2053	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	2054	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	2055	loop is now no longer controllable by EV. The C<Glib::EV> module does
2040	this.	2056	this.
2041		2057
2042	static gint	2058	static gint
2043	event_poll_func (GPollFD *fds, guint nfds, gint timeout)	2059	event_poll_func (GPollFD *fds, guint nfds, gint timeout)
2044	{	2060	{
2045	int got_events = 0;	2061	int got_events = 0;
2046		2062
2047	for (n = 0; n < nfds; ++n)	2063	for (n = 0; n < nfds; ++n)
2048	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events	2064	// create/start io watcher that sets the relevant bits in fds[n] and increment got_events
2049		2065
2050	if (timeout >= 0)	2066	if (timeout >= 0)
2051	// create/start timer	2067	// create/start timer
2052		2068
2053	// poll	2069	// poll
2054	ev_loop (EV_A_ 0);	2070	ev_loop (EV_A_ 0);
2055		2071
2056	// stop timer again	2072	// stop timer again
2057	if (timeout >= 0)	2073	if (timeout >= 0)
2058	ev_timer_stop (EV_A_ &to);	2074	ev_timer_stop (EV_A_ &to);
2059		2075
2060	// stop io watchers again - their callbacks should have set	2076	// stop io watchers again - their callbacks should have set
2061	for (n = 0; n < nfds; ++n)	2077	for (n = 0; n < nfds; ++n)
2062	ev_io_stop (EV_A_ iow [n]);	2078	ev_io_stop (EV_A_ iow [n]);
2063		2079
2064	return got_events;	2080	return got_events;
2065	}	2081	}
2066		2082
2067		2083
2068	=head2 C<ev_embed> - when one backend isn't enough...	2084	=head2 C<ev_embed> - when one backend isn't enough...
2069		2085
2070	This is a rather advanced watcher type that lets you embed one event loop	2086	This is a rather advanced watcher type that lets you embed one event loop
…		…
2126		2142
2127	Configures the watcher to embed the given loop, which must be	2143	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	2144	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	2145	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,	2146	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).	2147	if you do not want that, you need to temporarily stop the embed watcher).
2132		2148
2133	=item ev_embed_sweep (loop, ev_embed *)	2149	=item ev_embed_sweep (loop, ev_embed *)
2134		2150
2135	Make a single, non-blocking sweep over the embedded loop. This works	2151	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	2152	similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
2137	apropriate way for embedded loops.	2153	appropriate way for embedded loops.
2138		2154
2139	=item struct ev_loop *other [read-only]	2155	=item struct ev_loop *other [read-only]
2140		2156
2141	The embedded event loop.	2157	The embedded event loop.
2142		2158
…		…
2144		2160
2145	=head3 Examples	2161	=head3 Examples
2146		2162
2147	Example: Try to get an embeddable event loop and embed it into the default	2163	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	2164	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	2165	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	2166	C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
2151	used).	2167	used).
2152		2168
2153	struct ev_loop *loop_hi = ev_default_init (0);	2169	struct ev_loop *loop_hi = ev_default_init (0);
2154	struct ev_loop *loop_lo = 0;	2170	struct ev_loop *loop_lo = 0;
2155	struct ev_embed embed;	2171	struct ev_embed embed;
2156		2172
2157	// see if there is a chance of getting one that works	2173	// see if there is a chance of getting one that works
2158	// (remember that a flags value of 0 means autodetection)	2174	// (remember that a flags value of 0 means autodetection)
2159	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()	2175	loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
2160	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())	2176	? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
2161	: 0;	2177	: 0;
2162		2178
2163	// if we got one, then embed it, otherwise default to loop_hi	2179	// if we got one, then embed it, otherwise default to loop_hi
2164	if (loop_lo)	2180	if (loop_lo)
2165	{	2181	{
2166	ev_embed_init (&embed, 0, loop_lo);	2182	ev_embed_init (&embed, 0, loop_lo);
2167	ev_embed_start (loop_hi, &embed);	2183	ev_embed_start (loop_hi, &embed);
2168	}	2184	}
2169	else	2185	else
2170	loop_lo = loop_hi;	2186	loop_lo = loop_hi;
2171		2187
2172	Example: Check if kqueue is available but not recommended and create	2188	Example: Check if kqueue is available but not recommended and create
2173	a kqueue backend for use with sockets (which usually work with any	2189	a kqueue backend for use with sockets (which usually work with any
2174	kqueue implementation). Store the kqueue/socket-only event loop in	2190	kqueue implementation). Store the kqueue/socket-only event loop in
2175	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).	2191	C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
2176		2192
2177	struct ev_loop *loop = ev_default_init (0);	2193	struct ev_loop *loop = ev_default_init (0);
2178	struct ev_loop *loop_socket = 0;	2194	struct ev_loop *loop_socket = 0;
2179	struct ev_embed embed;	2195	struct ev_embed embed;
2180		2196
2181	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)	2197	if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
2182	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))	2198	if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
2183	{	2199	{
2184	ev_embed_init (&embed, 0, loop_socket);	2200	ev_embed_init (&embed, 0, loop_socket);
2185	ev_embed_start (loop, &embed);	2201	ev_embed_start (loop, &embed);
2186	}	2202	}
2187		2203
2188	if (!loop_socket)	2204	if (!loop_socket)
2189	loop_socket = loop;	2205	loop_socket = loop;
2190		2206
2191	// now use loop_socket for all sockets, and loop for everything else	2207	// now use loop_socket for all sockets, and loop for everything else
2192		2208
2193		2209
2194	=head2 C<ev_fork> - the audacity to resume the event loop after a fork	2210	=head2 C<ev_fork> - the audacity to resume the event loop after a fork
2195		2211
2196	Fork watchers are called when a C<fork ()> was detected (usually because	2212	Fork watchers are called when a C<fork ()> was detected (usually because
…		…
2249		2265
2250	=item queueing from a signal handler context	2266	=item queueing from a signal handler context
2251		2267
2252	To implement race-free queueing, you simply add to the queue in the signal	2268	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	2269	handler but you block the signal handler in the watcher callback. Here is an example that does that for
2254	some fictitiuous SIGUSR1 handler:	2270	some fictitious SIGUSR1 handler:
2255		2271
2256	static ev_async mysig;	2272	static ev_async mysig;
2257		2273
2258	static void	2274	static void
2259	sigusr1_handler (void)	2275	sigusr1_handler (void)
…		…
2333	=item ev_async_send (loop, ev_async *)	2349	=item ev_async_send (loop, ev_async *)
2334		2350
2335	Sends/signals/activates the given C<ev_async> watcher, that is, feeds	2351	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	2352	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	2353	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	2354	similar contexts (see the discussion of C<EV_ATOMIC_T> in the embedding
2339	section below on what exactly this means).	2355	section below on what exactly this means).
2340		2356
2341	This call incurs the overhead of a syscall only once per loop iteration,	2357	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	2358	so while the overhead might be noticeable, it doesn't apply to repeated
2343	calls to C<ev_async_send>.	2359	calls to C<ev_async_send>.
2344		2360
2345	=item bool = ev_async_pending (ev_async *)	2361	=item bool = ev_async_pending (ev_async *)
2346		2362
2347	Returns a non-zero value when C<ev_async_send> has been called on the	2363	Returns a non-zero value when C<ev_async_send> has been called on the
…		…
2349	event loop.	2365	event loop.
2350		2366
2351	C<ev_async_send> sets a flag in the watcher and wakes up the loop. When	2367	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,	2368	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	2369	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.	2370	quickly check whether invoking the loop might be a good idea.
2355		2371
2356	Not that this does I<not> check wether the watcher itself is pending, only	2372	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.	2373	whether it has been requested to make this watcher pending.
2358		2374
2359	=back	2375	=back
2360		2376
2361		2377
2362	=head1 OTHER FUNCTIONS	2378	=head1 OTHER FUNCTIONS
…		…
2373	or timeout without having to allocate/configure/start/stop/free one or	2389	or timeout without having to allocate/configure/start/stop/free one or
2374	more watchers yourself.	2390	more watchers yourself.
2375		2391
2376	If C<fd> is less than 0, then no I/O watcher will be started and events	2392	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	2393	is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and
2378	C<events> set will be craeted and started.	2394	C<events> set will be created and started.
2379		2395
2380	If C<timeout> is less than 0, then no timeout watcher will be	2396	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	2397	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	2398	repeat = 0) will be started. While C<0> is a valid timeout, it is of
2383	dubious value.	2399	dubious value.
…		…
2385	The callback has the type C<void (*cb)(int revents, void *arg)> and gets	2401	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	2402	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>	2403	C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg>
2388	value passed to C<ev_once>:	2404	value passed to C<ev_once>:
2389		2405
2390	static void stdin_ready (int revents, void *arg)	2406	static void stdin_ready (int revents, void *arg)
2391	{	2407	{
2392	if (revents & EV_TIMEOUT)	2408	if (revents & EV_TIMEOUT)
2393	/* doh, nothing entered */;	2409	/* doh, nothing entered */;
2394	else if (revents & EV_READ)	2410	else if (revents & EV_READ)
2395	/* stdin might have data for us, joy! */;	2411	/* stdin might have data for us, joy! */;
2396	}	2412	}
2397		2413
2398	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	2414	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
2399		2415
2400	=item ev_feed_event (ev_loop *, watcher *, int revents)	2416	=item ev_feed_event (ev_loop *, watcher *, int revents)
2401		2417
2402	Feeds the given event set into the event loop, as if the specified event	2418	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	2419	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	2424	Feed an event on the given fd, as if a file descriptor backend detected
2409	the given events it.	2425	the given events it.
2410		2426
2411	=item ev_feed_signal_event (ev_loop *loop, int signum)	2427	=item ev_feed_signal_event (ev_loop *loop, int signum)
2412		2428
2413	Feed an event as if the given signal occured (C<loop> must be the default	2429	Feed an event as if the given signal occurred (C<loop> must be the default
2414	loop!).	2430	loop!).
2415		2431
2416	=back	2432	=back
2417		2433
2418		2434
…		…
2447	=back	2463	=back
2448		2464
2449	=head1 C++ SUPPORT	2465	=head1 C++ SUPPORT
2450		2466
2451	Libev comes with some simplistic wrapper classes for C++ that mainly allow	2467	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	2468	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.	2469	the callback model to a model using method callbacks on objects.
2454		2470
2455	To use it,	2471	To use it,
2456		2472
2457	#include <ev++.h>	2473	#include <ev++.h>
2458		2474
2459	This automatically includes F<ev.h> and puts all of its definitions (many	2475	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	2476	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	2477	put into the C<ev> namespace. It should support all the same embedding
2462	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.	2478	options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
…		…
2529	your compiler is good :), then the method will be fully inlined into the	2545	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.	2546	thunking function, making it as fast as a direct C callback.
2531		2547
2532	Example: simple class declaration and watcher initialisation	2548	Example: simple class declaration and watcher initialisation
2533		2549
2534	struct myclass	2550	struct myclass
2535	{	2551	{
2536	void io_cb (ev::io &w, int revents) { }	2552	void io_cb (ev::io &w, int revents) { }
2537	}	2553	}
2538		2554
2539	myclass obj;	2555	myclass obj;
2540	ev::io iow;	2556	ev::io iow;
2541	iow.set <myclass, &myclass::io_cb> (&obj);	2557	iow.set <myclass, &myclass::io_cb> (&obj);
2542		2558
2543	=item w->set<function> (void *data = 0)	2559	=item w->set<function> (void *data = 0)
2544		2560
2545	Also sets a callback, but uses a static method or plain function as	2561	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	2562	callback. The optional C<data> argument will be stored in the watcher's
…		…
2550		2566
2551	See the method-C<set> above for more details.	2567	See the method-C<set> above for more details.
2552		2568
2553	Example:	2569	Example:
2554		2570
2555	static void io_cb (ev::io &w, int revents) { }	2571	static void io_cb (ev::io &w, int revents) { }
2556	iow.set <io_cb> ();	2572	iow.set <io_cb> ();
2557		2573
2558	=item w->set (struct ev_loop *)	2574	=item w->set (struct ev_loop *)
2559		2575
2560	Associates a different C<struct ev_loop> with this watcher. You can only	2576	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).	2577	do this when the watcher is inactive (and not pending either).
2562		2578
2563	=item w->set ([args])	2579	=item w->set ([arguments])
2564		2580
2565	Basically the same as C<ev_TYPE_set>, with the same args. Must be	2581	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	2582	called at least once. Unlike the C counterpart, an active watcher gets
2567	automatically stopped and restarted when reconfiguring it with this	2583	automatically stopped and restarted when reconfiguring it with this
2568	method.	2584	method.
2569		2585
2570	=item w->start ()	2586	=item w->start ()
…		…
2594	=back	2610	=back
2595		2611
2596	Example: Define a class with an IO and idle watcher, start one of them in	2612	Example: Define a class with an IO and idle watcher, start one of them in
2597	the constructor.	2613	the constructor.
2598		2614
2599	class myclass	2615	class myclass
2600	{	2616	{
2601	ev::io io; void io_cb (ev::io &w, int revents);	2617	ev::io io; void io_cb (ev::io &w, int revents);
2602	ev:idle idle void idle_cb (ev::idle &w, int revents);	2618	ev:idle idle void idle_cb (ev::idle &w, int revents);
2603		2619
2604	myclass (int fd)	2620	myclass (int fd)
2605	{	2621	{
2606	io .set <myclass, &myclass::io_cb > (this);	2622	io .set <myclass, &myclass::io_cb > (this);
2607	idle.set <myclass, &myclass::idle_cb> (this);	2623	idle.set <myclass, &myclass::idle_cb> (this);
2608		2624
2609	io.start (fd, ev::READ);	2625	io.start (fd, ev::READ);
2610	}	2626	}
2611	};	2627	};
2612		2628
2613		2629
2614	=head1 OTHER LANGUAGE BINDINGS	2630	=head1 OTHER LANGUAGE BINDINGS
2615		2631
2616	Libev does not offer other language bindings itself, but bindings for a	2632	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	2633	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	2634	any interesting language binding in addition to the ones listed here, drop
2619	me a note.	2635	me a note.
2620		2636
2621	=over 4	2637	=over 4
2622		2638
…		…
2626	libev. EV is developed together with libev. Apart from the EV core module,	2642	libev. EV is developed together with libev. Apart from the EV core module,
2627	there are additional modules that implement libev-compatible interfaces	2643	there are additional modules that implement libev-compatible interfaces
2628	to C<libadns> (C<EV::ADNS>), C<Net::SNMP> (C<Net::SNMP::EV>) and the	2644	to C<libadns> (C<EV::ADNS>), C<Net::SNMP> (C<Net::SNMP::EV>) and the
2629	C<libglib> event core (C<Glib::EV> and C<EV::Glib>).	2645	C<libglib> event core (C<Glib::EV> and C<EV::Glib>).
2630		2646
2631	It can be found and installed via CPAN, its homepage is found at	2647	It can be found and installed via CPAN, its homepage is at
2632	L<http://software.schmorp.de/pkg/EV>.	2648	L<http://software.schmorp.de/pkg/EV>.
2633		2649
		2650	=item Python
		2651
		2652	Python bindings can be found at L<http://code.google.com/p/pyev/>. It
		2653	seems to be quite complete and well-documented. Note, however, that the
		2654	patch they require for libev is outright dangerous as it breaks the ABI
		2655	for everybody else, and therefore, should never be applied in an installed
		2656	libev (if python requires an incompatible ABI then it needs to embed
		2657	libev).
		2658
2634	=item Ruby	2659	=item Ruby
2635		2660
2636	Tony Arcieri has written a ruby extension that offers access to a subset	2661	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	2662	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	2663	more on top of it. It can be found via gem servers. Its homepage is at
2639	L<http://rev.rubyforge.org/>.	2664	L<http://rev.rubyforge.org/>.
2640		2665
2641	=item D	2666	=item D
2642		2667
2643	Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to	2668	Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to
2644	be found at L<http://git.llucax.com.ar/?p=software/ev.d.git;a=summary>.	2669	be found at L<http://proj.llucax.com.ar/wiki/evd>.
2645		2670
2646	=back	2671	=back
2647		2672
2648		2673
2649	=head1 MACRO MAGIC	2674	=head1 MACRO MAGIC
2650		2675
2651	Libev can be compiled with a variety of options, the most fundamantal	2676	Libev can be compiled with a variety of options, the most fundamental
2652	of which is C<EV_MULTIPLICITY>. This option determines whether (most)	2677	of which is C<EV_MULTIPLICITY>. This option determines whether (most)
2653	functions and callbacks have an initial C<struct ev_loop *> argument.	2678	functions and callbacks have an initial C<struct ev_loop *> argument.
2654		2679
2655	To make it easier to write programs that cope with either variant, the	2680	To make it easier to write programs that cope with either variant, the
2656	following macros are defined:	2681	following macros are defined:
…		…
2661		2686
2662	This provides the loop I<argument> for functions, if one is required ("ev	2687	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,	2688	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:	2689	C<EV_A_> is used when other arguments are following. Example:
2665		2690
2666	ev_unref (EV_A);	2691	ev_unref (EV_A);
2667	ev_timer_add (EV_A_ watcher);	2692	ev_timer_add (EV_A_ watcher);
2668	ev_loop (EV_A_ 0);	2693	ev_loop (EV_A_ 0);
2669		2694
2670	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,	2695	It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
2671	which is often provided by the following macro.	2696	which is often provided by the following macro.
2672		2697
2673	=item C<EV_P>, C<EV_P_>	2698	=item C<EV_P>, C<EV_P_>
2674		2699
2675	This provides the loop I<parameter> for functions, if one is required ("ev	2700	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,	2701	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:	2702	C<EV_P_> is used when other parameters are following. Example:
2678		2703
2679	// this is how ev_unref is being declared	2704	// this is how ev_unref is being declared
2680	static void ev_unref (EV_P);	2705	static void ev_unref (EV_P);
2681		2706
2682	// this is how you can declare your typical callback	2707	// this is how you can declare your typical callback
2683	static void cb (EV_P_ ev_timer *w, int revents)	2708	static void cb (EV_P_ ev_timer *w, int revents)
2684		2709
2685	It declares a parameter C<loop> of type C<struct ev_loop *>, quite	2710	It declares a parameter C<loop> of type C<struct ev_loop *>, quite
2686	suitable for use with C<EV_A>.	2711	suitable for use with C<EV_A>.
2687		2712
2688	=item C<EV_DEFAULT>, C<EV_DEFAULT_>	2713	=item C<EV_DEFAULT>, C<EV_DEFAULT_>
…		…
2704		2729
2705	Example: Declare and initialise a check watcher, utilising the above	2730	Example: Declare and initialise a check watcher, utilising the above
2706	macros so it will work regardless of whether multiple loops are supported	2731	macros so it will work regardless of whether multiple loops are supported
2707	or not.	2732	or not.
2708		2733
2709	static void	2734	static void
2710	check_cb (EV_P_ ev_timer *w, int revents)	2735	check_cb (EV_P_ ev_timer *w, int revents)
2711	{	2736	{
2712	ev_check_stop (EV_A_ w);	2737	ev_check_stop (EV_A_ w);
2713	}	2738	}
2714		2739
2715	ev_check check;	2740	ev_check check;
2716	ev_check_init (&check, check_cb);	2741	ev_check_init (&check, check_cb);
2717	ev_check_start (EV_DEFAULT_ &check);	2742	ev_check_start (EV_DEFAULT_ &check);
2718	ev_loop (EV_DEFAULT_ 0);	2743	ev_loop (EV_DEFAULT_ 0);
2719		2744
2720	=head1 EMBEDDING	2745	=head1 EMBEDDING
2721		2746
2722	Libev can (and often is) directly embedded into host	2747	Libev can (and often is) directly embedded into host
2723	applications. Examples of applications that embed it include the Deliantra	2748	applications. Examples of applications that embed it include the Deliantra
…		…
2730	libev somewhere in your source tree).	2755	libev somewhere in your source tree).
2731		2756
2732	=head2 FILESETS	2757	=head2 FILESETS
2733		2758
2734	Depending on what features you need you need to include one or more sets of files	2759	Depending on what features you need you need to include one or more sets of files
2735	in your app.	2760	in your application.
2736		2761
2737	=head3 CORE EVENT LOOP	2762	=head3 CORE EVENT LOOP
2738		2763
2739	To include only the libev core (all the C<ev_*> functions), with manual	2764	To include only the libev core (all the C<ev_*> functions), with manual
2740	configuration (no autoconf):	2765	configuration (no autoconf):
2741		2766
2742	#define EV_STANDALONE 1	2767	#define EV_STANDALONE 1
2743	#include "ev.c"	2768	#include "ev.c"
2744		2769
2745	This will automatically include F<ev.h>, too, and should be done in a	2770	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	2771	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	2772	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	2773	done by writing a wrapper around F<ev.h> that you can include instead and
2749	where you can put other configuration options):	2774	where you can put other configuration options):
2750		2775
2751	#define EV_STANDALONE 1	2776	#define EV_STANDALONE 1
2752	#include "ev.h"	2777	#include "ev.h"
2753		2778
2754	Both header files and implementation files can be compiled with a C++	2779	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	2780	compiler (at least, thats a stated goal, and breakage will be treated
2756	as a bug).	2781	as a bug).
2757		2782
2758	You need the following files in your source tree, or in a directory	2783	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):	2784	in your include path (e.g. in libev/ when using -Ilibev):
2760		2785
2761	ev.h	2786	ev.h
2762	ev.c	2787	ev.c
2763	ev_vars.h	2788	ev_vars.h
2764	ev_wrap.h	2789	ev_wrap.h
2765		2790
2766	ev_win32.c required on win32 platforms only	2791	ev_win32.c required on win32 platforms only
2767		2792
2768	ev_select.c only when select backend is enabled (which is enabled by default)	2793	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)	2794	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)	2795	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)	2796	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)	2797	ev_port.c only when the solaris port backend is enabled (disabled by default)
2773		2798
2774	F<ev.c> includes the backend files directly when enabled, so you only need	2799	F<ev.c> includes the backend files directly when enabled, so you only need
2775	to compile this single file.	2800	to compile this single file.
2776		2801
2777	=head3 LIBEVENT COMPATIBILITY API	2802	=head3 LIBEVENT COMPATIBILITY API
2778		2803
2779	To include the libevent compatibility API, also include:	2804	To include the libevent compatibility API, also include:
2780		2805
2781	#include "event.c"	2806	#include "event.c"
2782		2807
2783	in the file including F<ev.c>, and:	2808	in the file including F<ev.c>, and:
2784		2809
2785	#include "event.h"	2810	#include "event.h"
2786		2811
2787	in the files that want to use the libevent API. This also includes F<ev.h>.	2812	in the files that want to use the libevent API. This also includes F<ev.h>.
2788		2813
2789	You need the following additional files for this:	2814	You need the following additional files for this:
2790		2815
2791	event.h	2816	event.h
2792	event.c	2817	event.c
2793		2818
2794	=head3 AUTOCONF SUPPORT	2819	=head3 AUTOCONF SUPPORT
2795		2820
2796	Instead of using C<EV_STANDALONE=1> and providing your config in	2821	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	2822	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	2823	F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then
2799	include F<config.h> and configure itself accordingly.	2824	include F<config.h> and configure itself accordingly.
2800		2825
2801	For this of course you need the m4 file:	2826	For this of course you need the m4 file:
2802		2827
2803	libev.m4	2828	libev.m4
2804		2829
2805	=head2 PREPROCESSOR SYMBOLS/MACROS	2830	=head2 PREPROCESSOR SYMBOLS/MACROS
2806		2831
2807	Libev can be configured via a variety of preprocessor symbols you have to	2832	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	2833	define before including any of its files. The default in the absence of
2809	autoconf is noted for every option.	2834	autoconf is noted for every option.
2810		2835
2811	=over 4	2836	=over 4
2812		2837
2813	=item EV_STANDALONE	2838	=item EV_STANDALONE
…		…
2819	F<event.h> that are not directly supported by the libev core alone.	2844	F<event.h> that are not directly supported by the libev core alone.
2820		2845
2821	=item EV_USE_MONOTONIC	2846	=item EV_USE_MONOTONIC
2822		2847
2823	If defined to be C<1>, libev will try to detect the availability of the	2848	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	2849	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	2850	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	2851	usually have to link against librt or something similar. Enabling it when
2827	the functionality isn't available is safe, though, although you have	2852	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>	2853	to make sure you link against any libraries where the C<clock_gettime>
2829	function is hiding in (often F<-lrt>).	2854	function is hiding in (often F<-lrt>).
2830		2855
2831	=item EV_USE_REALTIME	2856	=item EV_USE_REALTIME
2832		2857
2833	If defined to be C<1>, libev will try to detect the availability of the	2858	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	2859	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	2860	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	2861	be attempted. This effectively replaces C<gettimeofday> by C<clock_get
2837	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the	2862	(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
2838	note about libraries in the description of C<EV_USE_MONOTONIC>, though.	2863	note about libraries in the description of C<EV_USE_MONOTONIC>, though.
2839		2864
2840	=item EV_USE_NANOSLEEP	2865	=item EV_USE_NANOSLEEP
…		…
2851	2.7 or newer, otherwise disabled.	2876	2.7 or newer, otherwise disabled.
2852		2877
2853	=item EV_USE_SELECT	2878	=item EV_USE_SELECT
2854		2879
2855	If undefined or defined to be C<1>, libev will compile in support for the	2880	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	2881	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	2882	other method takes over, select will be it. Otherwise the select backend
2858	will not be compiled in.	2883	will not be compiled in.
2859		2884
2860	=item EV_SELECT_USE_FD_SET	2885	=item EV_SELECT_USE_FD_SET
2861		2886
2862	If defined to C<1>, then the select backend will use the system C<fd_set>	2887	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	2888	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	2889	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	2890	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	2891	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	2892	allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation, might
2868	influence the size of the C<fd_set> used.	2893	influence the size of the C<fd_set> used.
2869		2894
…		…
2918	otherwise another method will be used as fallback. This is the preferred	2943	otherwise another method will be used as fallback. This is the preferred
2919	backend for Solaris 10 systems.	2944	backend for Solaris 10 systems.
2920		2945
2921	=item EV_USE_DEVPOLL	2946	=item EV_USE_DEVPOLL
2922		2947
2923	reserved for future expansion, works like the USE symbols above.	2948	Reserved for future expansion, works like the USE symbols above.
2924		2949
2925	=item EV_USE_INOTIFY	2950	=item EV_USE_INOTIFY
2926		2951
2927	If defined to be C<1>, libev will compile in support for the Linux inotify	2952	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	2953	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	2960	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	2961	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"	2962	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.	2963	as well as for signal and thread safety in C<ev_async> watchers.
2939		2964
2940	In the absense of this define, libev will use C<sig_atomic_t volatile>	2965	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.	2966	(from F<signal.h>), which is usually good enough on most platforms.
2942		2967
2943	=item EV_H	2968	=item EV_H
2944		2969
2945	The name of the F<ev.h> header file used to include it. The default if	2970	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	3009	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	3010	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	3011	and time, so using the defaults of five priorities (-2 .. +2) is usually
2987	fine.	3012	fine.
2988		3013
2989	If your embedding app does not need any priorities, defining these both to	3014	If your embedding application does not need any priorities, defining these both to
2990	C<0> will save some memory and cpu.	3015	C<0> will save some memory and CPU.
2991		3016
2992	=item EV_PERIODIC_ENABLE	3017	=item EV_PERIODIC_ENABLE
2993		3018
2994	If undefined or defined to be C<1>, then periodic timers are supported. If	3019	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	3020	defined to be C<0>, then they are not. Disabling them saves a few kB of
…		…
3023		3048
3024	=item EV_MINIMAL	3049	=item EV_MINIMAL
3025		3050
3026	If you need to shave off some kilobytes of code at the expense of some	3051	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	3052	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	3053	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.	3054	much smaller 2-heap for timer management over the default 4-heap.
3030		3055
3031	=item EV_PID_HASHSIZE	3056	=item EV_PID_HASHSIZE
3032		3057
3033	C<ev_child> watchers use a small hash table to distribute workload by	3058	C<ev_child> watchers use a small hash table to distribute workload by
…		…
3046	=item EV_USE_4HEAP	3071	=item EV_USE_4HEAP
3047		3072
3048	Heaps are not very cache-efficient. To improve the cache-efficiency of the	3073	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	3074	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	3075	to C<1>. The 4-heap uses more complicated (longer) code but has
3051	noticably faster performance with many (thousands) of watchers.	3076	noticeably faster performance with many (thousands) of watchers.
3052		3077
3053	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	3078	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>
3054	(disabled).	3079	(disabled).
3055		3080
3056	=item EV_HEAP_CACHE_AT	3081	=item EV_HEAP_CACHE_AT
…		…
3058	Heaps are not very cache-efficient. To improve the cache-efficiency of the	3083	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	3084	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>),	3085	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,	3086	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	3087	but avoids random read accesses on heap changes. This improves performance
3063	noticably with with many (hundreds) of watchers.	3088	noticeably with with many (hundreds) of watchers.
3064		3089
3065	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>	3090	The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>
3066	(disabled).	3091	(disabled).
3067		3092
3068	=item EV_VERIFY	3093	=item EV_VERIFY
…		…
3085	members. You have to define it each time you include one of the files,	3110	members. You have to define it each time you include one of the files,
3086	though, and it must be identical each time.	3111	though, and it must be identical each time.
3087		3112
3088	For example, the perl EV module uses something like this:	3113	For example, the perl EV module uses something like this:
3089		3114
3090	#define EV_COMMON \	3115	#define EV_COMMON \
3091	SV *self; /* contains this struct */ \	3116	SV *self; /* contains this struct */ \
3092	SV *cb_sv, *fh /* note no trailing ";" */	3117	SV *cb_sv, *fh /* note no trailing ";" */
3093		3118
3094	=item EV_CB_DECLARE (type)	3119	=item EV_CB_DECLARE (type)
3095		3120
3096	=item EV_CB_INVOKE (watcher, revents)	3121	=item EV_CB_INVOKE (watcher, revents)
3097		3122
…		…
3104	avoid the C<struct ev_loop *> as first argument in all cases, or to use	3129	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++.	3130	method calls instead of plain function calls in C++.
3106		3131
3107	=head2 EXPORTED API SYMBOLS	3132	=head2 EXPORTED API SYMBOLS
3108		3133
3109	If you need to re-export the API (e.g. via a dll) and you need a list of	3134	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	3135	exported symbols, you can use the provided F<Symbol.*> files which list
3111	all public symbols, one per line:	3136	all public symbols, one per line:
3112		3137
3113	Symbols.ev for libev proper	3138	Symbols.ev for libev proper
3114	Symbols.event for the libevent emulation	3139	Symbols.event for the libevent emulation
3115		3140
3116	This can also be used to rename all public symbols to avoid clashes with	3141	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	3142	multiple versions of libev linked together (which is obviously bad in
3118	itself, but sometimes it is inconvinient to avoid this).	3143	itself, but sometimes it is inconvenient to avoid this).
3119		3144
3120	A sed command like this will create wrapper C<#define>'s that you need to	3145	A sed command like this will create wrapper C<#define>'s that you need to
3121	include before including F<ev.h>:	3146	include before including F<ev.h>:
3122		3147
3123	<Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h	3148	<Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h
…		…
3140	file.	3165	file.
3141		3166
3142	The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file	3167	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:	3168	that everybody includes and which overrides some configure choices:
3144		3169
3145	#define EV_MINIMAL 1	3170	#define EV_MINIMAL 1
3146	#define EV_USE_POLL 0	3171	#define EV_USE_POLL 0
3147	#define EV_MULTIPLICITY 0	3172	#define EV_MULTIPLICITY 0
3148	#define EV_PERIODIC_ENABLE 0	3173	#define EV_PERIODIC_ENABLE 0
3149	#define EV_STAT_ENABLE 0	3174	#define EV_STAT_ENABLE 0
3150	#define EV_FORK_ENABLE 0	3175	#define EV_FORK_ENABLE 0
3151	#define EV_CONFIG_H <config.h>	3176	#define EV_CONFIG_H <config.h>
3152	#define EV_MINPRI 0	3177	#define EV_MINPRI 0
3153	#define EV_MAXPRI 0	3178	#define EV_MAXPRI 0
3154		3179
3155	#include "ev++.h"	3180	#include "ev++.h"
3156		3181
3157	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:	3182	And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
3158		3183
3159	#include "ev_cpp.h"	3184	#include "ev_cpp.h"
3160	#include "ev.c"	3185	#include "ev.c"
3161		3186
3162		3187
3163	=head1 THREADS AND COROUTINES	3188	=head1 THREADS AND COROUTINES
3164		3189
3165	=head2 THREADS	3190	=head2 THREADS
3166		3191
3167	Libev itself is completely threadsafe, but it uses no locking. This	3192	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	3193	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	3194	only one thread ever calls into one libev function with the same loop
3170	parameter.	3195	parameter.
3171		3196
3172	Or put differently: calls with different loop parameters can be done in	3197	Or put differently: calls with different loop parameters can be done in
3173	parallel from multiple threads, calls with the same loop parameter must be	3198	parallel from multiple threads, calls with the same loop parameter must be
3174	done serially (but can be done from different threads, as long as only one	3199	done serially (but can be done from different threads, as long as only one
3175	thread ever is inside a call at any point in time, e.g. by using a mutex	3200	thread ever is inside a call at any point in time, e.g. by using a mutex
3176	per loop).	3201	per loop).
3177		3202
3178	If you want to know which design is best for your problem, then I cannot	3203	If you want to know which design (one loop, locking, or multiple loops
3179	help you but by giving some generic advice:	3204	without or something else still) is best for your problem, then I cannot
		3205	help you. I can give some generic advice however:
3180		3206
3181	=over 4	3207	=over 4
3182		3208
3183	=item * most applications have a main thread: use the default libev loop	3209	=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.	3210	in that thread, or create a separate thread running only the default loop.
3185		3211
3186	This helps integrating other libraries or software modules that use libev	3212	This helps integrating other libraries or software modules that use libev
3187	themselves and don't care/know about threading.	3213	themselves and don't care/know about threading.
3188		3214
3189	=item * one loop per thread is usually a good model.	3215	=item * one loop per thread is usually a good model.
3190		3216
3191	Doing this is almost never wrong, sometimes a better-performance model	3217	Doing this is almost never wrong, sometimes a better-performance model
3192	exists, but it is always a good start.	3218	exists, but it is always a good start.
3193		3219
3194	=item * other models exist, such as the leader/follower pattern, where one	3220	=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.	3221	loop is handed through multiple threads in a kind of round-robin fashion.
3196		3222
3197	Chosing a model is hard - look around, learn, know that usually you cna do	3223	Choosing a model is hard - look around, learn, know that usually you can do
3198	better than you currently do :-)	3224	better than you currently do :-)
3199		3225
3200	=item * often you need to talk to some other thread which blocks in the	3226	=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	3227	event loop - C<ev_async> watchers can be used to wake them up from other
3202	threads safely (or from signal contexts...).	3228	threads safely (or from signal contexts...).
3203		3229
3204	=back	3230	=back
3205		3231
3206	=head2 COROUTINES	3232	=head2 COROUTINES
3207		3233
3208	Libev is much more accomodating to coroutines ("cooperative threads"):	3234	Libev is much more accommodating to coroutines ("cooperative threads"):
3209	libev fully supports nesting calls to it's functions from different	3235	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	3236	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	3237	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	3238	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.	3239	you must not do this from C<ev_periodic> reschedule callbacks.
…		…
3261		3287
3262	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)	3288	=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
3263		3289
3264	A change means an I/O watcher gets started or stopped, which requires	3290	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	3291	libev to recalculate its status (and possibly tell the kernel, depending
3266	on backend and wether C<ev_io_set> was used).	3292	on backend and whether C<ev_io_set> was used).
3267		3293
3268	=item Activating one watcher (putting it into the pending state): O(1)	3294	=item Activating one watcher (putting it into the pending state): O(1)
3269		3295
3270	=item Priority handling: O(number_of_priorities)	3296	=item Priority handling: O(number_of_priorities)
3271		3297
…		…
3278		3304
3279	=item Processing ev_async_send: O(number_of_async_watchers)	3305	=item Processing ev_async_send: O(number_of_async_watchers)
3280		3306
3281	=item Processing signals: O(max_signal_number)	3307	=item Processing signals: O(max_signal_number)
3282		3308
3283	Sending involves a syscall I<iff> there were no other C<ev_async_send>	3309	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	3310	calls in the current loop iteration. Checking for async and signal events
3285	involves iterating over all running async watchers or all signal numbers.	3311	involves iterating over all running async watchers or all signal numbers.
3286		3312
3287	=back	3313	=back
3288		3314
3289		3315
3290	=head1 Win32 platform limitations and workarounds	3316	=head1 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
3291		3317
3292	Win32 doesn't support any of the standards (e.g. POSIX) that libev	3318	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	3319	requires, and its I/O model is fundamentally incompatible with the POSIX
3294	model. Libev still offers limited functionality on this platform in	3320	model. Libev still offers limited functionality on this platform in
3295	the form of the C<EVBACKEND_SELECT> backend, and only supports socket	3321	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).	3328	way (note also that glib is the slowest event library known to man).
3303		3329
3304	There is no supported compilation method available on windows except	3330	There is no supported compilation method available on windows except
3305	embedding it into other applications.	3331	embedding it into other applications.
3306		3332
		3333	Not a libev limitation but worth mentioning: windows apparently doesn't
		3334	accept large writes: instead of resulting in a partial write, windows will
		3335	either accept everything or return C<ENOBUFS> if the buffer is too large,
		3336	so make sure you only write small amounts into your sockets (less than a
		3337	megabyte seems safe, but thsi apparently depends on the amount of memory
		3338	available).
		3339
3307	Due to the many, low, and arbitrary limits on the win32 platform and	3340	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	3341	the abysmal performance of winsockets, using a large number of sockets
3309	is not recommended (and not reasonable). If your program needs to use	3342	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	3343	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	3344	different implementation for windows, as libev offers the POSIX readiness
3312	notification model, which cannot be implemented efficiently on windows	3345	notification model, which cannot be implemented efficiently on windows
3313	(microsoft monopoly games).	3346	(Microsoft monopoly games).
		3347
		3348	A typical way to use libev under windows is to embed it (see the embedding
		3349	section for details) and use the following F<evwrap.h> header file instead
		3350	of F<ev.h>:
		3351
		3352	#define EV_STANDALONE /* keeps ev from requiring config.h */
		3353	#define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
		3354
		3355	#include "ev.h"
		3356
		3357	And compile the following F<evwrap.c> file into your project (make sure
		3358	you do I<not> compile the F<ev.c> or any other embedded soruce files!):
		3359
		3360	#include "evwrap.h"
		3361	#include "ev.c"
3314		3362
3315	=over 4	3363	=over 4
3316		3364
3317	=item The winsocket select function	3365	=item The winsocket select function
3318		3366
3319	The winsocket C<select> function doesn't follow POSIX in that it	3367	The winsocket C<select> function doesn't follow POSIX in that it
3320	requires socket I<handles> and not socket I<file descriptors> (it is	3368	requires socket I<handles> and not socket I<file descriptors> (it is
3321	also extremely buggy). This makes select very inefficient, and also	3369	also extremely buggy). This makes select very inefficient, and also
3322	requires a mapping from file descriptors to socket handles. See the	3370	requires a mapping from file descriptors to socket handles (the Microsoft
		3371	C runtime provides the function C<_open_osfhandle> for this). See the
3323	discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and	3372	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.	3373	C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.
3325		3374
3326	The configuration for a "naked" win32 using the microsoft runtime	3375	The configuration for a "naked" win32 using the Microsoft runtime
3327	libraries and raw winsocket select is:	3376	libraries and raw winsocket select is:
3328		3377
3329	#define EV_USE_SELECT 1	3378	#define EV_USE_SELECT 1
3330	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */	3379	#define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
3331		3380
3332	Note that winsockets handling of fd sets is O(n), so you can easily get a	3381	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.	3382	complexity in the O(n²) range when using win32.
3334		3383
3335	=item Limited number of file descriptors	3384	=item Limited number of file descriptors
3336		3385
3337	Windows has numerous arbitrary (and low) limits on things.	3386	Windows has numerous arbitrary (and low) limits on things.
3338		3387
3339	Early versions of winsocket's select only supported waiting for a maximum	3388	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	3389	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	3390	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	3391	recommends spawning a chain of threads and wait for 63 handles and the
3343	previous thread in each. Great).	3392	previous thread in each. Great).
3344		3393
3345	Newer versions support more handles, but you need to define C<FD_SETSIZE>	3394	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	3395	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	3396	call (which might be in libev or elsewhere, for example, perl does its own
3348	select emulation on windows).	3397	select emulation on windows).
3349		3398
3350	Another limit is the number of file descriptors in the microsoft runtime	3399	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	3400	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	3401	or something like this inside Microsoft). You can increase this by calling
3353	C<_setmaxstdio>, which can increase this limit to C<2048> (another	3402	C<_setmaxstdio>, which can increase this limit to C<2048> (another
3354	arbitrary limit), but is broken in many versions of the microsoft runtime	3403	arbitrary limit), but is broken in many versions of the Microsoft runtime
3355	libraries.	3404	libraries.
3356		3405
3357	This might get you to about C<512> or C<2048> sockets (depending on	3406	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	3407	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	3408	wrap all I/O functions and provide your own fd management, but the cost of
…		…
3366		3415
3367	In addition to a working ISO-C implementation, libev relies on a few	3416	In addition to a working ISO-C implementation, libev relies on a few
3368	additional extensions:	3417	additional extensions:
3369		3418
3370	=over 4	3419	=over 4
		3420
		3421	=item C<void (*)(ev_watcher_type *, int revents)> must have compatible
		3422	calling conventions regardless of C<ev_watcher_type *>.
		3423
		3424	Libev assumes not only that all watcher pointers have the same internal
		3425	structure (guaranteed by POSIX but not by ISO C for example), but it also
		3426	assumes that the same (machine) code can be used to call any watcher
		3427	callback: The watcher callbacks have different type signatures, but libev
		3428	calls them using an C<ev_watcher *> internally.
3371		3429
3372	=item C<sig_atomic_t volatile> must be thread-atomic as well	3430	=item C<sig_atomic_t volatile> must be thread-atomic as well
3373		3431
3374	The type C<sig_atomic_t volatile> (or whatever is defined as	3432	The type C<sig_atomic_t volatile> (or whatever is defined as
3375	C<EV_ATOMIC_T>) must be atomic w.r.t. accesses from different	3433	C<EV_ATOMIC_T>) must be atomic w.r.t. accesses from different
…		…
3416	scared by this.	3474	scared by this.
3417		3475
3418	However, these are unavoidable for many reasons. For one, each compiler	3476	However, these are unavoidable for many reasons. For one, each compiler
3419	has different warnings, and each user has different tastes regarding	3477	has different warnings, and each user has different tastes regarding
3420	warning options. "Warn-free" code therefore cannot be a goal except when	3478	warning options. "Warn-free" code therefore cannot be a goal except when
3421	targetting a specific compiler and compiler-version.	3479	targeting a specific compiler and compiler-version.
3422		3480
3423	Another reason is that some compiler warnings require elaborate	3481	Another reason is that some compiler warnings require elaborate
3424	workarounds, or other changes to the code that make it less clear and less	3482	workarounds, or other changes to the code that make it less clear and less
3425	maintainable.	3483	maintainable.
3426		3484
3427	And of course, some compiler warnings are just plain stupid, or simply	3485	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	3486	wrong (because they don't actually warn about the condition their message
3429	seems to warn about).	3487	seems to warn about).
3430		3488
3431	While libev is written to generate as few warnings as possible,	3489	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	3490	"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	3491	with any compiler warnings enabled unless you are prepared to cope with
…		…
3445		3503
3446	==2274== definitely lost: 0 bytes in 0 blocks.	3504	==2274== definitely lost: 0 bytes in 0 blocks.
3447	==2274== possibly lost: 0 bytes in 0 blocks.	3505	==2274== possibly lost: 0 bytes in 0 blocks.
3448	==2274== still reachable: 256 bytes in 1 blocks.	3506	==2274== still reachable: 256 bytes in 1 blocks.
3449		3507
3450	then there is no memory leak. Similarly, under some circumstances,	3508	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	3509	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).	3510	might be confused (it is a very good tool, but only a tool).
3453		3511
3454	If you are unsure about something, feel free to contact the mailing list	3512	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	3513	with the full valgrind report and an explanation on why you think this is

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