[ViewVC] Diff of: cvs/EV/README

Comparing EV/README (file contents):
Revision 1.14 by root, Wed Nov 28 19:22:16 2007 UTC vs.
Revision 1.26 by root, Wed May 21 23:40:08 2008 UTC

…		…
2	EV - perl interface to libev, a high performance full-featured event	2	EV - perl interface to libev, a high performance full-featured event
3	loop	3	loop
4		4
5	SYNOPSIS	5	SYNOPSIS
6	use EV;	6	use EV;
7		7
8	# TIMERS	8	# TIMERS
9		9
10	my $w = EV::timer 2, 0, sub {	10	my $w = EV::timer 2, 0, sub {
11	warn "is called after 2s";	11	warn "is called after 2s";
12	};	12	};
13		13
14	my $w = EV::timer 2, 2, sub {	14	my $w = EV::timer 2, 2, sub {
15	warn "is called roughly every 2s (repeat = 2)";	15	warn "is called roughly every 2s (repeat = 2)";
16	};	16	};
17		17
18	undef $w; # destroy event watcher again	18	undef $w; # destroy event watcher again
19		19
20	my $w = EV::periodic 0, 60, 0, sub {	20	my $w = EV::periodic 0, 60, 0, sub {
21	warn "is called every minute, on the minute, exactly";	21	warn "is called every minute, on the minute, exactly";
22	};	22	};
23
24	# IO	23
25		24	# IO
		25
26	my $w = EV::io *STDIN, EV::READ, sub {	26	my $w = EV::io *STDIN, EV::READ, sub {
27	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask	27	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28	warn "stdin is readable, you entered: ", <STDIN>;	28	warn "stdin is readable, you entered: ", <STDIN>;
29	};	29	};
30		30
31	# SIGNALS	31	# SIGNALS
32		32
33	my $w = EV::signal 'QUIT', sub {	33	my $w = EV::signal 'QUIT', sub {
34	warn "sigquit received\n";	34	warn "sigquit received\n";
35	};	35	};
36		36
37	# CHILD/PID STATUS CHANGES	37	# CHILD/PID STATUS CHANGES
38		38
39	my $w = EV::child 666, sub {	39	my $w = EV::child 666, 0, sub {
40	my ($w, $revents) = @_;	40	my ($w, $revents) = @_;
41	my $status = $w->rstatus;	41	my $status = $w->rstatus;
42	};	42	};
43		43
44	# STAT CHANGES	44	# STAT CHANGES
45	my $w = EV::stat "/etc/passwd", 10, sub {	45	my $w = EV::stat "/etc/passwd", 10, sub {
46	my ($w, $revents) = @_;	46	my ($w, $revents) = @_;
47	warn $w->path, " has changed somehow.\n";	47	warn $w->path, " has changed somehow.\n";
48	};	48	};
49		49
50	# MAINLOOP	50	# MAINLOOP
51	EV::loop; # loop until EV::unloop is called or all watchers stop	51	EV::loop; # loop until EV::unloop is called or all watchers stop
52	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	52	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
53	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	53	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
54		54
55	DESCRIPTION	55	DESCRIPTION
56	This module provides an interface to libev	56	This module provides an interface to libev
57	(<http://software.schmorp.de/pkg/libev.html>). While the documentation	57	(<http://software.schmorp.de/pkg/libev.html>). While the documentation
58	below is comprehensive, one might also consult the documentation of	58	below is comprehensive, one might also consult the documentation of
59	libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle	59	libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>)
60	details on watcher semantics or some discussion on the available	60	for more subtle details on watcher semantics or some discussion on the
61	backends, or how to force a specific backend with "LIBEV_FLAGS".	61	available backends, or how to force a specific backend with
		62	"LIBEV_FLAGS", or just about in any case because it has much more
		63	detailed information.
		64
		65	This module is very fast and scalable. It is actually so fast that you
		66	can use it through the AnyEvent module, stay portable to other event
		67	loops (if you don't rely on any watcher types not available through it)
		68	and still be faster than with any other event loop currently supported
		69	in Perl.
		70
		71	EVENT LOOPS
		72	EV supports multiple event loops: There is a single "default event loop"
		73	that can handle everything including signals and child watchers, and any
		74	number of "dynamic event loops" that can use different backends (with
		75	various limitations), but no child and signal watchers.
		76
		77	You do not have to do anything to create the default event loop: When
		78	the module is loaded a suitable backend is selected on the premise of
		79	selecting a working backend (which for example rules out kqueue on most
		80	BSDs). Modules should, unless they have "special needs" always use the
		81	default loop as this is fastest (perl-wise), best supported by other
		82	modules (e.g. AnyEvent or Coro) and most portable event loop.
		83
		84	For specific programs you can create additional event loops dynamically.
		85
		86	$loop = new EV::loop [$flags]
		87	Create a new event loop as per the specified flags. Please refer to
		88	the "ev_loop_new ()" function description in the libev documentation
		89	(<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
		90	ONS>) for more info.
		91
		92	The loop will automatically be destroyed when it is no longer
		93	referenced by any watcher and the loop object goes out of scope.
		94
		95	Using "EV::FLAG_FORKCHECK" is recommended, as only the default event
		96	loop is protected by this module.
		97
		98	$loop->loop_fork
		99	Must be called after a fork in the child, before entering or
		100	continuing the event loop. An alternative is to use
		101	"EV::FLAG_FORKCHECK" which calls this fucntion automatically, at
		102	some performance loss (refer to the libev documentation).
		103
		104	$loop = EV::default_loop [$flags]
		105	Return the default loop (which is a singleton object).
62		106
63	BASIC INTERFACE	107	BASIC INTERFACE
64	$EV::DIED	108	$EV::DIED
65	Must contain a reference to a function that is called when a	109	Must contain a reference to a function that is called when a
66	callback throws an exception (with $@ containing thr error). The	110	callback throws an exception (with $@ containing the error). The
67	default prints an informative message and continues.	111	default prints an informative message and continues.
68		112
69	If this callback throws an exception it will be silently ignored.	113	If this callback throws an exception it will be silently ignored.
		114
		115	$flags = EV::supported_backends
		116	$flags = EV::recommended_backends
		117	$flags = EV::embeddable_backends
		118	Returns the set (see "EV::BACKEND_*" flags) of backends supported by
		119	this instance of EV, the set of recommended backends (supposed to be
		120	good) for this platform and the set of embeddable backends (see
		121	EMBED WATCHERS).
		122
		123	EV::sleep $seconds
		124	Block the process for the given number of (fractional) seconds.
70		125
71	$time = EV::time	126	$time = EV::time
72	Returns the current time in (fractional) seconds since the epoch.	127	Returns the current time in (fractional) seconds since the epoch.
73		128
74	$time = EV::now	129	$time = EV::now
		130	$time = $loop->now
75	Returns the time the last event loop iteration has been started.	131	Returns the time the last event loop iteration has been started.
76	This is the time that (relative) timers are based on, and refering	132	This is the time that (relative) timers are based on, and refering
77	to it is usually faster then calling EV::time.	133	to it is usually faster then calling EV::time.
78		134
79	$method = EV::method	135	$backend = EV::backend
		136	$backend = $loop->backend
80	Returns an integer describing the backend used by libev	137	Returns an integer describing the backend used by libev
81	(EV::METHOD_SELECT or EV::METHOD_EPOLL).	138	(EV::METHOD_SELECT or EV::METHOD_EPOLL).
82		139
83	EV::loop [$flags]	140	EV::loop [$flags]
		141	$loop->loop ([$flags])
84	Begin checking for events and calling callbacks. It returns when a	142	Begin checking for events and calling callbacks. It returns when a
85	callback calls EV::unloop.	143	callback calls EV::unloop.
86		144
87	The $flags argument can be one of the following:	145	The $flags argument can be one of the following:
88		146
89	0 as above	147	0 as above
90	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	148	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
91	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	149	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
92		150
93	EV::unloop [$how]	151	EV::unloop [$how]
		152	$loop->unloop ([$how])
94	When called with no arguments or an argument of EV::UNLOOP_ONE,	153	When called with no arguments or an argument of EV::UNLOOP_ONE,
95	makes the innermost call to EV::loop return.	154	makes the innermost call to EV::loop return.
96		155
97	When called with an argument of EV::UNLOOP_ALL, all calls to	156	When called with an argument of EV::UNLOOP_ALL, all calls to
98	EV::loop will return as fast as possible.	157	EV::loop will return as fast as possible.
99		158
		159	$count = EV::loop_count
		160	$count = $loop->loop_count
		161	Return the number of times the event loop has polled for new events.
		162	Sometiems useful as a generation counter.
		163
100	EV::once $fh_or_undef, $events, $timeout, $cb->($revents)	164	EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		165	$loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
101	This function rolls together an I/O and a timer watcher for a single	166	This function rolls together an I/O and a timer watcher for a single
102	one-shot event without the need for managing a watcher object.	167	one-shot event without the need for managing a watcher object.
103		168
104	If $fh_or_undef is a filehandle or file descriptor, then $events	169	If $fh_or_undef is a filehandle or file descriptor, then $events
105	must be a bitset containing either "EV::READ", "EV::WRITE" or	170	must be a bitset containing either "EV::READ", "EV::WRITE" or
…		…
110	If timeout is "undef" or negative, then there will be no timeout.	175	If timeout is "undef" or negative, then there will be no timeout.
111	Otherwise a EV::timer with this value will be started.	176	Otherwise a EV::timer with this value will be started.
112		177
113	When an error occurs or either the timeout or I/O watcher triggers,	178	When an error occurs or either the timeout or I/O watcher triggers,
114	then the callback will be called with the received event set (in	179	then the callback will be called with the received event set (in
115	general you can expect it to be a combination of "EV:ERROR",	180	general you can expect it to be a combination of "EV::ERROR",
116	"EV::READ", "EV::WRITE" and "EV::TIMEOUT").	181	"EV::READ", "EV::WRITE" and "EV::TIMEOUT").
117		182
118	EV::once doesn't return anything: the watchers stay active till	183	EV::once doesn't return anything: the watchers stay active till
119	either of them triggers, then they will be stopped and freed, and	184	either of them triggers, then they will be stopped and freed, and
120	the callback invoked.	185	the callback invoked.
121		186
		187	EV::feed_fd_event ($fd, $revents)
		188	$loop->feed_fd_event ($fd, $revents)
		189	Feed an event on a file descriptor into EV. EV will react to this
		190	call as if the readyness notifications specified by $revents (a
		191	combination of "EV::READ" and "EV::WRITE") happened on the file
		192	descriptor $fd.
		193
		194	EV::feed_signal_event ($signal)
		195	Feed a signal event into EV. EV will react to this call as if the
		196	signal specified by $signal had occured.
		197
		198	EV::set_io_collect_interval $time
		199	$loop->set_io_collect_interval ($time)
		200	EV::set_timeout_collect_interval $time
		201	$loop->set_timeout_collect_interval ($time)
		202	These advanced functions set the minimum block interval when polling
		203	for I/O events and the minimum wait interval for timer events. See
		204	the libev documentation at
		205	<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
		206	ROLLING_THE_EVENT_LOOP> for a more detailed discussion.
		207
122	WATCHER OBJECTS	208	WATCHER OBJECTS
123	A watcher is an object that gets created to record your interest in some	209	A watcher is an object that gets created to record your interest in some
124	event. For instance, if you want to wait for STDIN to become readable,	210	event. For instance, if you want to wait for STDIN to become readable,
125	you would create an EV::io watcher for that:	211	you would create an EV::io watcher for that:
126		212
127	my $watcher = EV::io *STDIN, EV::READ, sub {	213	my $watcher = EV::io *STDIN, EV::READ, sub {
128	my ($watcher, $revents) = @_;	214	my ($watcher, $revents) = @_;
129	warn "yeah, STDIN should not be readable without blocking!\n"	215	warn "yeah, STDIN should now be readable without blocking!\n"
130	};	216	};
131		217
132	All watchers can be active (waiting for events) or inactive (paused).	218	All watchers can be active (waiting for events) or inactive (paused).
133	Only active watchers will have their callbacks invoked. All callbacks	219	Only active watchers will have their callbacks invoked. All callbacks
134	will be called with at least two arguments: the watcher and a bitmask of	220	will be called with at least two arguments: the watcher and a bitmask of
135	received events.	221	received events.
136		222
137	Each watcher type has its associated bit in revents, so you can use the	223	Each watcher type has its associated bit in revents, so you can use the
138	same callback for multiple watchers. The event mask is named after the	224	same callback for multiple watchers. The event mask is named after the
139	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	225	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
140	EV::periodic sets EV::PERIODIC and so on, with the exception of IO	226	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
141	events (which can set both EV::READ and EV::WRITE bits), and EV::timer	227	events (which can set both EV::READ and EV::WRITE bits), and EV::timer
142	(which uses EV::TIMEOUT).	228	(which uses EV::TIMEOUT).
143		229
144	In the rare case where one wants to create a watcher but not start it at	230	In the rare case where one wants to create a watcher but not start it at
145	the same time, each constructor has a variant with a trailing "_ns" in	231	the same time, each constructor has a variant with a trailing "_ns" in
…		…
163	stopped watchers).	249	stopped watchers).
164		250
165	$w->stop	251	$w->stop
166	Stop a watcher if it is active. Also clear any pending events	252	Stop a watcher if it is active. Also clear any pending events
167	(events that have been received but that didn't yet result in a	253	(events that have been received but that didn't yet result in a
168	callback invocation), regardless of wether the watcher was active or	254	callback invocation), regardless of whether the watcher was active
169	not.	255	or not.
170		256
171	$bool = $w->is_active	257	$bool = $w->is_active
172	Returns true if the watcher is active, false otherwise.	258	Returns true if the watcher is active, false otherwise.
173		259
174	$current_data = $w->data	260	$current_data = $w->data
…		…
197	The default priority of any newly-created watcher is 0.	283	The default priority of any newly-created watcher is 0.
198		284
199	Note that the priority semantics have not yet been fleshed out and	285	Note that the priority semantics have not yet been fleshed out and
200	are subject to almost certain change.	286	are subject to almost certain change.
201		287
202	$w->trigger ($revents)	288	$w->invoke ($revents)
203	Call the callback now with the given event mask.	289	Call the callback now with the given event mask.
		290
		291	$w->feed_event ($revents)
		292	Feed some events on this watcher into EV. EV will react to this call
		293	as if the watcher had received the given $revents mask.
		294
		295	$revents = $w->clear_pending
		296	If the watcher is pending, this function clears its pending status
		297	and returns its $revents bitset (as if its callback was invoked). If
		298	the watcher isn't pending it does nothing and returns 0.
204		299
205	$previous_state = $w->keepalive ($bool)	300	$previous_state = $w->keepalive ($bool)
206	Normally, "EV::loop" will return when there are no active watchers	301	Normally, "EV::loop" will return when there are no active watchers
207	(which is a "deadlock" because no progress can be made anymore).	302	(which is a "deadlock" because no progress can be made anymore).
208	This is convinient because it allows you to start your watchers (and	303	This is convinient because it allows you to start your watchers (and
209	your jobs), call "EV::loop" once and when it returns you know that	304	your jobs), call "EV::loop" once and when it returns you know that
210	all your jobs are finished (or they forgot to register some watchers	305	all your jobs are finished (or they forgot to register some watchers
211	for their task :).	306	for their task :).
212		307
213	Sometimes, however, this gets in your way, for example when you the	308	Sometimes, however, this gets in your way, for example when the
214	module that calls "EV::loop" (usually the main program) is not the	309	module that calls "EV::loop" (usually the main program) is not the
215	same module as a long-living watcher (for example a DNS client	310	same module as a long-living watcher (for example a DNS client
216	module written by somebody else even). Then you might want any	311	module written by somebody else even). Then you might want any
217	outstanding requests to be handled, but you would not want to keep	312	outstanding requests to be handled, but you would not want to keep
218	"EV::loop" from returning just because you happen to have this	313	"EV::loop" from returning just because you happen to have this
…		…
223	returning.	318	returning.
224		319
225	The initial value for keepalive is true (enabled), and you cna	320	The initial value for keepalive is true (enabled), and you cna
226	change it any time.	321	change it any time.
227		322
228	Example: Register an IO watcher for some UDP socket but do not keep	323	Example: Register an I/O watcher for some UDP socket but do not keep
229	the event loop from running just because of that watcher.	324	the event loop from running just because of that watcher.
230		325
231	my $udp_socket = ...	326	my $udp_socket = ...
232	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };	327	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
233	$udp_watcher->keepalive (0);	328	$1000udp_watcher->keepalive (0);
234		329
		330	$loop = $w->loop
		331	Return the loop that this watcher is attached to.
		332
235	WATCHER TYPES	333	WATCHER TYPES
236	Each of the following subsections describes a single watcher type.	334	Each of the following subsections describes a single watcher type.
237		335
238	IO WATCHERS - is this file descriptor readable or writable?	336	I/O WATCHERS - is this file descriptor readable or writable?
239	$w = EV::io $fileno_or_fh, $eventmask, $callback	337	$w = EV::io $fileno_or_fh, $eventmask, $callback
240	$w = EV::io_ns $fileno_or_fh, $eventmask, $callback	338	$w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		339	$w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		340	$w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
241	As long as the returned watcher object is alive, call the $callback	341	As long as the returned watcher object is alive, call the $callback
242	when at least one of events specified in $eventmask occurs.	342	when at least one of events specified in $eventmask occurs.
243		343
244	The $eventmask can be one or more of these constants ORed together:	344	The $eventmask can be one or more of these constants ORed together:
245		345
…		…
262	Returns the previously set event mask and optionally set a new one.	362	Returns the previously set event mask and optionally set a new one.
263		363
264	TIMER WATCHERS - relative and optionally repeating timeouts	364	TIMER WATCHERS - relative and optionally repeating timeouts
265	$w = EV::timer $after, $repeat, $callback	365	$w = EV::timer $after, $repeat, $callback
266	$w = EV::timer_ns $after, $repeat, $callback	366	$w = EV::timer_ns $after, $repeat, $callback
		367	$w = $loop->timer ($after, $repeat, $callback)
		368	$w = $loop->timer_ns ($after, $repeat, $callback)
267	Calls the callback after $after seconds (which may be fractional).	369	Calls the callback after $after seconds (which may be fractional).
268	If $repeat is non-zero, the timer will be restarted (with the	370	If $repeat is non-zero, the timer will be restarted (with the
269	$repeat value as $after) after the callback returns.	371	$repeat value as $after) after the callback returns.
270		372
271	This means that the callback would be called roughly after $after	373	This means that the callback would be called roughly after $after
…		…
307	method on the timeout.	409	method on the timeout.
308		410
309	PERIODIC WATCHERS - to cron or not to cron?	411	PERIODIC WATCHERS - to cron or not to cron?
310	$w = EV::periodic $at, $interval, $reschedule_cb, $callback	412	$w = EV::periodic $at, $interval, $reschedule_cb, $callback
311	$w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	413	$w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		414	$w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		415	$w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
312	Similar to EV::timer, but is not based on relative timeouts but on	416	Similar to EV::timer, but is not based on relative timeouts but on
313	absolute times. Apart from creating "simple" timers that trigger	417	absolute times. Apart from creating "simple" timers that trigger
314	"at" the specified time, it can also be used for non-drifting	418	"at" the specified time, it can also be used for non-drifting
315	absolute timers and more complex, cron-like, setups that are not	419	absolute timers and more complex, cron-like, setups that are not
316	adversely affected by time jumps (i.e. when the system clock is	420	adversely affected by time jumps (i.e. when the system clock is
317	changed by explicit date -s or other means such as ntpd). It is also	421	changed by explicit date -s or other means such as ntpd). It is also
318	the most complex watcher type in EV.	422	the most complex watcher type in EV.
319		423
320	It has three distinct "modes":	424	It has three distinct "modes":
321		425
322	* absolute timer ($interval = $reschedule_cb = 0)	426	* absolute timer ($interval = $reschedule_cb = 0)
		427
323	This time simply fires at the wallclock time $at and doesn't	428	This time simply fires at the wallclock time $at and doesn't
324	repeat. It will not adjust when a time jump occurs, that is, if	429	repeat. It will not adjust when a time jump occurs, that is, if
325	it is to be run at January 1st 2011 then it will run when the	430	it is to be run at January 1st 2011 then it will run when the
326	system time reaches or surpasses this time.	431	system time reaches or surpasses this time.
327		432
328	* non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	433	* repeating interval timer ($interval > 0, $reschedule_cb = 0)
		434
329	In this mode the watcher will always be scheduled to time out at	435	In this mode the watcher will always be scheduled to time out at
330	the next "$at + N * $interval" time (for some integer N) and	436	the next "$at + N * $interval" time (for some integer N) and
331	then repeat, regardless of any time jumps.	437	then repeat, regardless of any time jumps.
332		438
333	This can be used to create timers that do not drift with respect	439	This can be used to create timers that do not drift with respect
…		…
342	Another way to think about it (for the mathematically inclined)	448	Another way to think about it (for the mathematically inclined)
343	is that EV::periodic will try to run the callback in this mode	449	is that EV::periodic will try to run the callback in this mode
344	at the next possible time where "$time = $at (mod $interval)",	450	at the next possible time where "$time = $at (mod $interval)",
345	regardless of any time jumps.	451	regardless of any time jumps.
346		452
347	* manual reschedule mode ($reschedule_cb = coderef)	453	* manual reschedule mode ($reschedule_cb = coderef)
		454
348	In this mode $interval and $at are both being ignored. Instead,	455	In this mode $interval and $at are both being ignored. Instead,
349	each time the periodic watcher gets scheduled, the reschedule	456	each time the periodic watcher gets scheduled, the reschedule
350	callback ($reschedule_cb) will be called with the watcher as	457	callback ($reschedule_cb) will be called with the watcher as
351	first, and the current time as second argument.	458	first, and the current time as second argument.
352		459
353	*This callback MUST NOT stop or destroy this or any other	460	*This callback MUST NOT stop or destroy this or any other
		461	periodic watcher, ever, and MUST NOT call any event loop
354	periodic watcher, ever*. If you need to stop it, return 1e30 and	462	functions or methods*. If you need to stop it, return 1e30 and
355	stop it afterwards.	463	stop it afterwards. You may create and start a "EV::prepare"
		464	watcher for this task.
356		465
357	It must return the next time to trigger, based on the passed	466	It must return the next time to trigger, based on the passed
358	time value (that is, the lowest time value larger than to the	467	time value (that is, the lowest time value larger than or equal
359	second argument). It will usually be called just before the	468	to to the second argument). It will usually be called just
360	callback will be triggered, but might be called at other times,	469	before the callback will be triggered, but might be called at
361	too.	470	other times, too.
362		471
363	This can be used to create very complex timers, such as a timer	472	This can be used to create very complex timers, such as a timer
364	that triggers on each midnight, local time (actually 24 hours	473	that triggers on each midnight, local time (actually 24 hours
365	after the last midnight, to keep the example simple. If you know	474	after the last midnight, to keep the example simple. If you know
366	a way to do it correctly in about the same space (without	475	a way to do it correctly in about the same space (without
…		…
384	be called at any time.	493	be called at any time.
385		494
386	$w->again	495	$w->again
387	Simply stops and starts the watcher again.	496	Simply stops and starts the watcher again.
388		497
		498	$time = $w->at
		499	Return the time that the watcher is expected to trigger next.
		500
389	SIGNAL WATCHERS - signal me when a signal gets signalled!	501	SIGNAL WATCHERS - signal me when a signal gets signalled!
390	$w = EV::signal $signal, $callback	502	$w = EV::signal $signal, $callback
391	$w = EV::signal_ns $signal, $callback	503	$w = EV::signal_ns $signal, $callback
392	Call the callback when $signal is received (the signal can be	504	Call the callback when $signal is received (the signal can be
393	specified by number or by name, just as with "kill" or %SIG).	505	specified by number or by name, just as with "kill" or %SIG).
…		…
410	$old_signum = $w->signal ($new_signal)	522	$old_signum = $w->signal ($new_signal)
411	Returns the previously set signal (always as a number not name) and	523	Returns the previously set signal (always as a number not name) and
412	optionally set a new one.	524	optionally set a new one.
413		525
414	CHILD WATCHERS - watch out for process status changes	526	CHILD WATCHERS - watch out for process status changes
415	$w = EV::child $pid, $callback	527	$w = EV::child $pid, $trace, $callback
416	$w = EV::child_ns $pid, $callback	528	$w = EV::child_ns $pid, $trace, $callback
		529	$w = $loop->child ($pid, $trace, $callback)
		530	$w = $loop->child_ns ($pid, $trace, $callback)
417	Call the callback when a status change for pid $pid (or any pid if	531	Call the callback when a status change for pid $pid (or any pid if
418	$pid is 0) has been received. More precisely: when the process	532	$pid is 0) has been received (a status change happens when the
		533	process terminates or is killed, or, when trace is true,
		534	additionally when it is stopped or continued). More precisely: when
419	receives a "SIGCHLD", EV will fetch the outstanding exit/wait status	535	the process receives a "SIGCHLD", EV will fetch the outstanding
420	for all changed/zombie children and call the callback.	536	exit/wait status for all changed/zombie children and call the
		537	callback.
421		538
422	It is valid (and fully supported) to install a child watcher after a	539	It is valid (and fully supported) to install a child watcher after a
423	child has exited but before the event loop has started its next	540	child has exited but before the event loop has started its next
424	iteration (for example, first you "fork", then the new child process	541	iteration (for example, first you "fork", then the new child process
425	might exit, and only then do you install a child watcher in the	542	might exit, and only then do you install a child watcher in the
…		…
432	be called.	549	be called.
433		550
434	The "child_ns" variant doesn't start (activate) the newly created	551	The "child_ns" variant doesn't start (activate) the newly created
435	watcher.	552	watcher.
436		553
437	$w->set ($pid)	554	$w->set ($pid, $trace)
438	Reconfigures the watcher, see the constructor above for details. Can	555	Reconfigures the watcher, see the constructor above for details. Can
439	be called at any time.	556	be called at any time.
440		557
441	$current_pid = $w->pid	558	$current_pid = $w->pid
442	$old_pid = $w->pid ($new_pid)
443	Returns the previously set process id and optionally set a new one.	559	Returns the previously set process id and optionally set a new one.
444		560
445	$exit_status = $w->rstatus	561	$exit_status = $w->rstatus
446	Return the exit/wait status (as returned by waitpid, see the waitpid	562	Return the exit/wait status (as returned by waitpid, see the waitpid
447	entry in perlfunc).	563	entry in perlfunc).
…		…
451	a watcher for all pids).	567	a watcher for all pids).
452		568
453	STAT WATCHERS - did the file attributes just change?	569	STAT WATCHERS - did the file attributes just change?
454	$w = EV::stat $path, $interval, $callback	570	$w = EV::stat $path, $interval, $callback
455	$w = EV::stat_ns $path, $interval, $callback	571	$w = EV::stat_ns $path, $interval, $callback
		572	$w = $loop->stat ($path, $interval, $callback)
		573	$w = $loop->stat_ns ($path, $interval, $callback)
456	Call the callback when a file status change has been detected on	574	Call the callback when a file status change has been detected on
457	$path. The $path does not need to exist, changing from "path exists"	575	$path. The $path does not need to exist, changing from "path exists"
458	to "path does not exist" is a status change like any other.	576	to "path does not exist" is a status change like any other.
459		577
460	The $interval is a recommended polling interval for systems where	578	The $interval is a recommended polling interval for systems where
…		…
520	Can be used to query the actual interval used.	638	Can be used to query the actual interval used.
521		639
522	IDLE WATCHERS - when you've got nothing better to do...	640	IDLE WATCHERS - when you've got nothing better to do...
523	$w = EV::idle $callback	641	$w = EV::idle $callback
524	$w = EV::idle_ns $callback	642	$w = EV::idle_ns $callback
		643	$w = $loop->idle ($callback)
		644	$w = $loop->idle_ns ($callback)
525	Call the callback when there are no pending io, timer/periodic,	645	Call the callback when there are no other pending watchers of the
526	signal or child events, i.e. when the process is idle.	646	same or higher priority (excluding check, prepare and other idle
		647	watchers of the same or lower priority, of course). They are called
		648	idle watchers because when the watcher is the highest priority
		649	pending event in the process, the process is considered to be idle
		650	at that priority.
		651
		652	If you want a watcher that is only ever called when no other
		653	events are outstanding you have to set the priority to "EV::MINPRI".
527		654
528	The process will not block as long as any idle watchers are active,	655	The process will not block as long as any idle watchers are active,
529	and they will be called repeatedly until stopped.	656	and they will be called repeatedly until stopped.
		657
		658	For example, if you have idle watchers at priority 0 and 1, and an
		659	I/O watcher at priority 0, then the idle watcher at priority 1 and
		660	the I/O watcher will always run when ready. Only when the idle
		661	watcher at priority 1 is stopped and the I/O watcher at priority 0
		662	is not pending with the 0-priority idle watcher be invoked.
530		663
531	The "idle_ns" variant doesn't start (activate) the newly created	664	The "idle_ns" variant doesn't start (activate) the newly created
532	watcher.	665	watcher.
533		666
534	PREPARE WATCHERS - customise your event loop!	667	PREPARE WATCHERS - customise your event loop!
535	$w = EV::prepare $callback	668	$w = EV::prepare $callback
536	$w = EV::prepare_ns $callback	669	$w = EV::prepare_ns $callback
		670	$w = $loop->prepare ($callback)
		671	$w = $loop->prepare_ns ($callback)
537	Call the callback just before the process would block. You can still	672	Call the callback just before the process would block. You can still
538	create/modify any watchers at this point.	673	create/modify any watchers at this point.
539		674
540	See the EV::check watcher, below, for explanations and an example.	675	See the EV::check watcher, below, for explanations and an example.
541		676
…		…
543	watcher.	678	watcher.
544		679
545	CHECK WATCHERS - customise your event loop even more!	680	CHECK WATCHERS - customise your event loop even more!
546	$w = EV::check $callback	681	$w = EV::check $callback
547	$w = EV::check_ns $callback	682	$w = EV::check_ns $callback
		683	$w = $loop->check ($callback)
		684	$w = $loop->check_ns ($callback)
548	Call the callback just after the process wakes up again (after it	685	Call the callback just after the process wakes up again (after it
549	has gathered events), but before any other callbacks have been	686	has gathered events), but before any other callbacks have been
550	invoked.	687	invoked.
551		688
552	This is used to integrate other event-based software into the EV	689	This is used to integrate other event-based software into the EV
…		…
563	or return;	700	or return;
564		701
565	# make the dispatcher handle any outstanding stuff	702	# make the dispatcher handle any outstanding stuff
566	... not shown	703	... not shown
567		704
568	# create an IO watcher for each and every socket	705	# create an I/O watcher for each and every socket
569	@snmp_watcher = (	706	@snmp_watcher = (
570	(map { EV::io $_, EV::READ, sub { } }	707	(map { EV::io $_, EV::READ, sub { } }
571	keys %{ $dispatcher->{_descriptors} }),	708	keys %{ $dispatcher->{_descriptors} }),
572		709
573	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	710	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
601	is done before the event loop blocks next and before "check" watchers	738	is done before the event loop blocks next and before "check" watchers
602	are being called, and only in the child after the fork.	739	are being called, and only in the child after the fork.
603		740
604	$w = EV::fork $callback	741	$w = EV::fork $callback
605	$w = EV::fork_ns $callback	742	$w = EV::fork_ns $callback
		743	$w = $loop->fork ($callback)
		744	$w = $loop->fork_ns ($callback)
606	Call the callback before the event loop is resumed in the child	745	Call the callback before the event loop is resumed in the child
607	process after a fork.	746	process after a fork.
608		747
609	The "fork_ns" variant doesn't start (activate) the newly created	748	The "fork_ns" variant doesn't start (activate) the newly created
610	watcher.	749	watcher.
		750
		751	EMBED WATCHERS - when one backend isn't enough...
		752	This is a rather advanced watcher type that lets you embed one event
		753	loop into another (currently only IO events are supported in the
		754	embedded loop, other types of watchers might be handled in a delayed or
		755	incorrect fashion and must not be used).
		756
		757	See the libev documentation at
		758	<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
		759	_when_one_backend_> for more details.
		760
		761	In short, this watcher is most useful on BSD systems without working
		762	kqueue to still be able to handle a large number of sockets:
		763
		764	my $socket_loop;
		765
		766	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		767	if (
		768	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		769	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		770	) {
		771	# use kqueue for sockets
		772	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		773	}
		774
		775	# use the default loop otherwise
		776	$socket_loop \|\|= EV::default_loop;
		777
		778	$w = EV::embed $otherloop, $callback
		779	$w = EV::embed_ns $otherloop, $callback
		780	$w = $loop->embed ($otherloop, $callback)
		781	$w = $loop->embed_ns ($otherloop, $callback)
		782	Call the callback when the embedded event loop ($otherloop) has any
		783	I/O activity. The $callback should alwas be specified as "undef" in
		784	this version of EV, which means the embedded event loop will be
		785	managed automatically.
		786
		787	The "embed_ns" variant doesn't start (activate) the newly created
		788	watcher.
		789
		790	ASYNC WATCHERS - how to wake up another event loop
		791	Async watchers are provided by EV, but have little use in perl directly,
		792	as perl neither supports threads nor direct access to signal handlers or
		793	other contexts where they could be of value.
		794
		795	It is, however, possible to use them from the XS level.
		796
		797	Please see the libev documentation for further details.
		798
		799	$w = EV::async $callback
		800	$w = EV::async_ns $callback
		801	$w->send
		802	$bool = $w->async_pending
		803
		804	PERL SIGNALS
		805	While Perl signal handling (%SIG) is not affected by EV, the behaviour
		806	with EV is as the same as any other C library: Perl-signals will only be
		807	handled when Perl runs, which means your signal handler might be invoked
		808	only the next time an event callback is invoked.
		809
		810	The solution is to use EV signal watchers (see "EV::signal"), which will
		811	ensure proper operations with regards to other event watchers.
		812
		813	If you cannot do this for whatever reason, you can also force a watcher
		814	to be called on every event loop iteration by installing a "EV::check"
		815	watcher:
		816
		817	my $async_check = EV::check sub { };
		818
		819	This ensures that perl gets into control for a short time to handle any
		820	pending signals, and also ensures (slightly) slower overall operation.
611		821
612	THREADS	822	THREADS
613	Threads are not supported by this module in any way. Perl pseudo-threads	823	Threads are not supported by this module in any way. Perl pseudo-threads
614	is evil stuff and must die. As soon as Perl gains real threads I will	824	is evil stuff and must die. As soon as Perl gains real threads I will
615	work on thread support for it.	825	work on thread support for it.
…		…
630		840
631	On win32, there is no notion of fork so all this doesn't apply, of	841	On win32, there is no notion of fork so all this doesn't apply, of
632	course.	842	course.
633		843
634	SEE ALSO	844	SEE ALSO
635	EV::DNS.	845	EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
		846	loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
		847	with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
		848	agnostic and portable event driven programming.
636		849
637	AUTHOR	850	AUTHOR
638	Marc Lehmann <schmorp@schmorp.de>	851	Marc Lehmann <schmorp@schmorp.de>
639	http://home.schmorp.de/	852	http://home.schmorp.de/
640		853

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Comparing EV/README (file contents): Revision 1.14 by root, Wed Nov 28 19:22:16 2007 UTC vs. Revision 1.26 by root, Wed May 21 23:40:08 2008 UTC

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Comparing EV/README (file contents):
Revision 1.14 by root, Wed Nov 28 19:22:16 2007 UTC vs.
Revision 1.26 by root, Wed May 21 23:40:08 2008 UTC