[ViewVC] Diff of: cvs/EV/README

Comparing EV/README (file contents):
Revision 1.15 by root, Wed Dec 5 14:06:50 2007 UTC vs.
Revision 1.25 by root, Sun May 18 10:45:36 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
100	$count = EV::loop_count	159	$count = EV::loop_count
		160	$count = $loop->loop_count
101	Return the number of times the event loop has polled for new events.	161	Return the number of times the event loop has polled for new events.
102	Sometiems useful as a generation counter.	162	Sometiems useful as a generation counter.
103		163
104	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))
105	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
106	one-shot event without the need for managing a watcher object.	167	one-shot event without the need for managing a watcher object.
107		168
108	If $fh_or_undef is a filehandle or file descriptor, then $events	169	If $fh_or_undef is a filehandle or file descriptor, then $events
109	must be a bitset containing either "EV::READ", "EV::WRITE" or	170	must be a bitset containing either "EV::READ", "EV::WRITE" or
…		…
114	If timeout is "undef" or negative, then there will be no timeout.	175	If timeout is "undef" or negative, then there will be no timeout.
115	Otherwise a EV::timer with this value will be started.	176	Otherwise a EV::timer with this value will be started.
116		177
117	When an error occurs or either the timeout or I/O watcher triggers,	178	When an error occurs or either the timeout or I/O watcher triggers,
118	then the callback will be called with the received event set (in	179	then the callback will be called with the received event set (in
119	general you can expect it to be a combination of "EV:ERROR",	180	general you can expect it to be a combination of "EV::ERROR",
120	"EV::READ", "EV::WRITE" and "EV::TIMEOUT").	181	"EV::READ", "EV::WRITE" and "EV::TIMEOUT").
121		182
122	EV::once doesn't return anything: the watchers stay active till	183	EV::once doesn't return anything: the watchers stay active till
123	either of them triggers, then they will be stopped and freed, and	184	either of them triggers, then they will be stopped and freed, and
124	the callback invoked.	185	the callback invoked.
125		186
		187	EV::feed_fd_event ($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
126	WATCHER OBJECTS	208	WATCHER OBJECTS
127	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
128	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,
129	you would create an EV::io watcher for that:	211	you would create an EV::io watcher for that:
130		212
131	my $watcher = EV::io *STDIN, EV::READ, sub {	213	my $watcher = EV::io *STDIN, EV::READ, sub {
132	my ($watcher, $revents) = @_;	214	my ($watcher, $revents) = @_;
133	warn "yeah, STDIN should not be readable without blocking!\n"	215	warn "yeah, STDIN should now be readable without blocking!\n"
134	};	216	};
135		217
136	All watchers can be active (waiting for events) or inactive (paused).	218	All watchers can be active (waiting for events) or inactive (paused).
137	Only active watchers will have their callbacks invoked. All callbacks	219	Only active watchers will have their callbacks invoked. All callbacks
138	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
139	received events.	221	received events.
140		222
141	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
142	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
143	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,
144	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
145	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
146	(which uses EV::TIMEOUT).	228	(which uses EV::TIMEOUT).
147		229
148	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
149	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
…		…
167	stopped watchers).	249	stopped watchers).
168		250
169	$w->stop	251	$w->stop
170	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
171	(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
172	callback invocation), regardless of wether the watcher was active or	254	callback invocation), regardless of whether the watcher was active
173	not.	255	or not.
174		256
175	$bool = $w->is_active	257	$bool = $w->is_active
176	Returns true if the watcher is active, false otherwise.	258	Returns true if the watcher is active, false otherwise.
177		259
178	$current_data = $w->data	260	$current_data = $w->data
…		…
201	The default priority of any newly-created watcher is 0.	283	The default priority of any newly-created watcher is 0.
202		284
203	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
204	are subject to almost certain change.	286	are subject to almost certain change.
205		287
206	$w->trigger ($revents)	288	$w->invoke ($revents)
207	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.
208		299
209	$previous_state = $w->keepalive ($bool)	300	$previous_state = $w->keepalive ($bool)
210	Normally, "EV::loop" will return when there are no active watchers	301	Normally, "EV::loop" will return when there are no active watchers
211	(which is a "deadlock" because no progress can be made anymore).	302	(which is a "deadlock" because no progress can be made anymore).
212	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
213	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
214	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
215	for their task :).	306	for their task :).
216		307
217	Sometimes, however, this gets in your way, for example when you the	308	Sometimes, however, this gets in your way, for example when the
218	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
219	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
220	module written by somebody else even). Then you might want any	311	module written by somebody else even). Then you might want any
221	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
222	"EV::loop" from returning just because you happen to have this	313	"EV::loop" from returning just because you happen to have this
…		…
227	returning.	318	returning.
228		319
229	The initial value for keepalive is true (enabled), and you cna	320	The initial value for keepalive is true (enabled), and you cna
230	change it any time.	321	change it any time.
231		322
232	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
233	the event loop from running just because of that watcher.	324	the event loop from running just because of that watcher.
234		325
235	my $udp_socket = ...	326	my $udp_socket = ...
236	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };	327	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
237	$udp_watcher->keepalive (0);	328	$1000udp_watcher->keepalive (0);
238		329
		330	$loop = $w->loop
		331	Return the loop that this watcher is attached to.
		332
239	WATCHER TYPES	333	WATCHER TYPES
240	Each of the following subsections describes a single watcher type.	334	Each of the following subsections describes a single watcher type.
241		335
242	IO WATCHERS - is this file descriptor readable or writable?	336	I/O WATCHERS - is this file descriptor readable or writable?
243	$w = EV::io $fileno_or_fh, $eventmask, $callback	337	$w = EV::io $fileno_or_fh, $eventmask, $callback
244	$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)
245	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
246	when at least one of events specified in $eventmask occurs.	342	when at least one of events specified in $eventmask occurs.
247		343
248	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:
249		345
…		…
266	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.
267		363
268	TIMER WATCHERS - relative and optionally repeating timeouts	364	TIMER WATCHERS - relative and optionally repeating timeouts
269	$w = EV::timer $after, $repeat, $callback	365	$w = EV::timer $after, $repeat, $callback
270	$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)
271	Calls the callback after $after seconds (which may be fractional).	369	Calls the callback after $after seconds (which may be fractional).
272	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
273	$repeat value as $after) after the callback returns.	371	$repeat value as $after) after the callback returns.
274		372
275	This means that the callback would be called roughly after $after	373	This means that the callback would be called roughly after $after
…		…
311	method on the timeout.	409	method on the timeout.
312		410
313	PERIODIC WATCHERS - to cron or not to cron?	411	PERIODIC WATCHERS - to cron or not to cron?
314	$w = EV::periodic $at, $interval, $reschedule_cb, $callback	412	$w = EV::periodic $at, $interval, $reschedule_cb, $callback
315	$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, $callback)
316	Similar to EV::timer, but is not based on relative timeouts but on	416	Similar to EV::timer, but is not based on relative timeouts but on
317	absolute times. Apart from creating "simple" timers that trigger	417	absolute times. Apart from creating "simple" timers that trigger
318	"at" the specified time, it can also be used for non-drifting	418	"at" the specified time, it can also be used for non-drifting
319	absolute timers and more complex, cron-like, setups that are not	419	absolute timers and more complex, cron-like, setups that are not
320	adversely affected by time jumps (i.e. when the system clock is	420	adversely affected by time jumps (i.e. when the system clock is
321	changed by explicit date -s or other means such as ntpd). It is also	421	changed by explicit date -s or other means such as ntpd). It is also
322	the most complex watcher type in EV.	422	the most complex watcher type in EV.
323		423
324	It has three distinct "modes":	424	It has three distinct "modes":
325		425
326	* absolute timer ($interval = $reschedule_cb = 0)	426	* absolute timer ($interval = $reschedule_cb = 0)
		427
327	This time simply fires at the wallclock time $at and doesn't	428	This time simply fires at the wallclock time $at and doesn't
328	repeat. It will not adjust when a time jump occurs, that is, if	429	repeat. It will not adjust when a time jump occurs, that is, if
329	it is to be run at January 1st 2011 then it will run when the	430	it is to be run at January 1st 2011 then it will run when the
330	system time reaches or surpasses this time.	431	system time reaches or surpasses this time.
331		432
332	* non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	433	* repeating interval timer ($interval > 0, $reschedule_cb = 0)
		434
333	In this mode the watcher will always be scheduled to time out at	435	In this mode the watcher will always be scheduled to time out at
334	the next "$at + N * $interval" time (for some integer N) and	436	the next "$at + N * $interval" time (for some integer N) and
335	then repeat, regardless of any time jumps.	437	then repeat, regardless of any time jumps.
336		438
337	This can be used to create timers that do not drift with respect	439	This can be used to create timers that do not drift with respect
…		…
346	Another way to think about it (for the mathematically inclined)	448	Another way to think about it (for the mathematically inclined)
347	is that EV::periodic will try to run the callback in this mode	449	is that EV::periodic will try to run the callback in this mode
348	at the next possible time where "$time = $at (mod $interval)",	450	at the next possible time where "$time = $at (mod $interval)",
349	regardless of any time jumps.	451	regardless of any time jumps.
350		452
351	* manual reschedule mode ($reschedule_cb = coderef)	453	* manual reschedule mode ($reschedule_cb = coderef)
		454
352	In this mode $interval and $at are both being ignored. Instead,	455	In this mode $interval and $at are both being ignored. Instead,
353	each time the periodic watcher gets scheduled, the reschedule	456	each time the periodic watcher gets scheduled, the reschedule
354	callback ($reschedule_cb) will be called with the watcher as	457	callback ($reschedule_cb) will be called with the watcher as
355	first, and the current time as second argument.	458	first, and the current time as second argument.
356		459
…		…
388	be called at any time.	491	be called at any time.
389		492
390	$w->again	493	$w->again
391	Simply stops and starts the watcher again.	494	Simply stops and starts the watcher again.
392		495
		496	$time = $w->at
		497	Return the time that the watcher is expected to trigger next.
		498
393	SIGNAL WATCHERS - signal me when a signal gets signalled!	499	SIGNAL WATCHERS - signal me when a signal gets signalled!
394	$w = EV::signal $signal, $callback	500	$w = EV::signal $signal, $callback
395	$w = EV::signal_ns $signal, $callback	501	$w = EV::signal_ns $signal, $callback
396	Call the callback when $signal is received (the signal can be	502	Call the callback when $signal is received (the signal can be
397	specified by number or by name, just as with "kill" or %SIG).	503	specified by number or by name, just as with "kill" or %SIG).
…		…
414	$old_signum = $w->signal ($new_signal)	520	$old_signum = $w->signal ($new_signal)
415	Returns the previously set signal (always as a number not name) and	521	Returns the previously set signal (always as a number not name) and
416	optionally set a new one.	522	optionally set a new one.
417		523
418	CHILD WATCHERS - watch out for process status changes	524	CHILD WATCHERS - watch out for process status changes
419	$w = EV::child $pid, $callback	525	$w = EV::child $pid, $trace, $callback
420	$w = EV::child_ns $pid, $callback	526	$w = EV::child_ns $pid, $trace, $callback
		527	$w = $loop->child ($pid, $trace, $callback)
		528	$w = $loop->child_ns ($pid, $trace, $callback)
421	Call the callback when a status change for pid $pid (or any pid if	529	Call the callback when a status change for pid $pid (or any pid if
422	$pid is 0) has been received. More precisely: when the process	530	$pid is 0) has been received (a status change happens when the
		531	process terminates or is killed, or, when trace is true,
		532	additionally when it is stopped or continued). More precisely: when
423	receives a "SIGCHLD", EV will fetch the outstanding exit/wait status	533	the process receives a "SIGCHLD", EV will fetch the outstanding
424	for all changed/zombie children and call the callback.	534	exit/wait status for all changed/zombie children and call the
		535	callback.
425		536
426	It is valid (and fully supported) to install a child watcher after a	537	It is valid (and fully supported) to install a child watcher after a
427	child has exited but before the event loop has started its next	538	child has exited but before the event loop has started its next
428	iteration (for example, first you "fork", then the new child process	539	iteration (for example, first you "fork", then the new child process
429	might exit, and only then do you install a child watcher in the	540	might exit, and only then do you install a child watcher in the
…		…
436	be called.	547	be called.
437		548
438	The "child_ns" variant doesn't start (activate) the newly created	549	The "child_ns" variant doesn't start (activate) the newly created
439	watcher.	550	watcher.
440		551
441	$w->set ($pid)	552	$w->set ($pid, $trace)
442	Reconfigures the watcher, see the constructor above for details. Can	553	Reconfigures the watcher, see the constructor above for details. Can
443	be called at any time.	554	be called at any time.
444		555
445	$current_pid = $w->pid	556	$current_pid = $w->pid
446	$old_pid = $w->pid ($new_pid)
447	Returns the previously set process id and optionally set a new one.	557	Returns the previously set process id and optionally set a new one.
448		558
449	$exit_status = $w->rstatus	559	$exit_status = $w->rstatus
450	Return the exit/wait status (as returned by waitpid, see the waitpid	560	Return the exit/wait status (as returned by waitpid, see the waitpid
451	entry in perlfunc).	561	entry in perlfunc).
…		…
455	a watcher for all pids).	565	a watcher for all pids).
456		566
457	STAT WATCHERS - did the file attributes just change?	567	STAT WATCHERS - did the file attributes just change?
458	$w = EV::stat $path, $interval, $callback	568	$w = EV::stat $path, $interval, $callback
459	$w = EV::stat_ns $path, $interval, $callback	569	$w = EV::stat_ns $path, $interval, $callback
		570	$w = $loop->stat ($path, $interval, $callback)
		571	$w = $loop->stat_ns ($path, $interval, $callback)
460	Call the callback when a file status change has been detected on	572	Call the callback when a file status change has been detected on
461	$path. The $path does not need to exist, changing from "path exists"	573	$path. The $path does not need to exist, changing from "path exists"
462	to "path does not exist" is a status change like any other.	574	to "path does not exist" is a status change like any other.
463		575
464	The $interval is a recommended polling interval for systems where	576	The $interval is a recommended polling interval for systems where
…		…
524	Can be used to query the actual interval used.	636	Can be used to query the actual interval used.
525		637
526	IDLE WATCHERS - when you've got nothing better to do...	638	IDLE WATCHERS - when you've got nothing better to do...
527	$w = EV::idle $callback	639	$w = EV::idle $callback
528	$w = EV::idle_ns $callback	640	$w = EV::idle_ns $callback
		641	$w = $loop->idle ($callback)
		642	$w = $loop->idle_ns ($callback)
529	Call the callback when there are no pending io, timer/periodic,	643	Call the callback when there are no other pending watchers of the
530	signal or child events, i.e. when the process is idle.	644	same or higher priority (excluding check, prepare and other idle
		645	watchers of the same or lower priority, of course). They are called
		646	idle watchers because when the watcher is the highest priority
		647	pending event in the process, the process is considered to be idle
		648	at that priority.
		649
		650	If you want a watcher that is only ever called when no other
		651	events are outstanding you have to set the priority to "EV::MINPRI".
531		652
532	The process will not block as long as any idle watchers are active,	653	The process will not block as long as any idle watchers are active,
533	and they will be called repeatedly until stopped.	654	and they will be called repeatedly until stopped.
		655
		656	For example, if you have idle watchers at priority 0 and 1, and an
		657	I/O watcher at priority 0, then the idle watcher at priority 1 and
		658	the I/O watcher will always run when ready. Only when the idle
		659	watcher at priority 1 is stopped and the I/O watcher at priority 0
		660	is not pending with the 0-priority idle watcher be invoked.
534		661
535	The "idle_ns" variant doesn't start (activate) the newly created	662	The "idle_ns" variant doesn't start (activate) the newly created
536	watcher.	663	watcher.
537		664
538	PREPARE WATCHERS - customise your event loop!	665	PREPARE WATCHERS - customise your event loop!
539	$w = EV::prepare $callback	666	$w = EV::prepare $callback
540	$w = EV::prepare_ns $callback	667	$w = EV::prepare_ns $callback
		668	$w = $loop->prepare ($callback)
		669	$w = $loop->prepare_ns ($callback)
541	Call the callback just before the process would block. You can still	670	Call the callback just before the process would block. You can still
542	create/modify any watchers at this point.	671	create/modify any watchers at this point.
543		672
544	See the EV::check watcher, below, for explanations and an example.	673	See the EV::check watcher, below, for explanations and an example.
545		674
…		…
547	watcher.	676	watcher.
548		677
549	CHECK WATCHERS - customise your event loop even more!	678	CHECK WATCHERS - customise your event loop even more!
550	$w = EV::check $callback	679	$w = EV::check $callback
551	$w = EV::check_ns $callback	680	$w = EV::check_ns $callback
		681	$w = $loop->check ($callback)
		682	$w = $loop->check_ns ($callback)
552	Call the callback just after the process wakes up again (after it	683	Call the callback just after the process wakes up again (after it
553	has gathered events), but before any other callbacks have been	684	has gathered events), but before any other callbacks have been
554	invoked.	685	invoked.
555		686
556	This is used to integrate other event-based software into the EV	687	This is used to integrate other event-based software into the EV
…		…
567	or return;	698	or return;
568		699
569	# make the dispatcher handle any outstanding stuff	700	# make the dispatcher handle any outstanding stuff
570	... not shown	701	... not shown
571		702
572	# create an IO watcher for each and every socket	703	# create an I/O watcher for each and every socket
573	@snmp_watcher = (	704	@snmp_watcher = (
574	(map { EV::io $_, EV::READ, sub { } }	705	(map { EV::io $_, EV::READ, sub { } }
575	keys %{ $dispatcher->{_descriptors} }),	706	keys %{ $dispatcher->{_descriptors} }),
576		707
577	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	708	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
605	is done before the event loop blocks next and before "check" watchers	736	is done before the event loop blocks next and before "check" watchers
606	are being called, and only in the child after the fork.	737	are being called, and only in the child after the fork.
607		738
608	$w = EV::fork $callback	739	$w = EV::fork $callback
609	$w = EV::fork_ns $callback	740	$w = EV::fork_ns $callback
		741	$w = $loop->fork ($callback)
		742	$w = $loop->fork_ns ($callback)
610	Call the callback before the event loop is resumed in the child	743	Call the callback before the event loop is resumed in the child
611	process after a fork.	744	process after a fork.
612		745
613	The "fork_ns" variant doesn't start (activate) the newly created	746	The "fork_ns" variant doesn't start (activate) the newly created
614	watcher.	747	watcher.
		748
		749	EMBED WATCHERS - when one backend isn't enough...
		750	This is a rather advanced watcher type that lets you embed one event
		751	loop into another (currently only IO events are supported in the
		752	embedded loop, other types of watchers might be handled in a delayed or
		753	incorrect fashion and must not be used).
		754
		755	See the libev documentation at
		756	<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
		757	_when_one_backend_> for more details.
		758
		759	In short, this watcher is most useful on BSD systems without working
		760	kqueue to still be able to handle a large number of sockets:
		761
		762	my $socket_loop;
		763
		764	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		765	if (
		766	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		767	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		768	) {
		769	# use kqueue for sockets
		770	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		771	}
		772
		773	# use the default loop otherwise
		774	$socket_loop \|\|= EV::default_loop;
		775
		776	$w = EV::embed $otherloop, $callback
		777	$w = EV::embed_ns $otherloop, $callback
		778	$w = $loop->embed ($otherloop, $callback)
		779	$w = $loop->embed_ns ($otherloop, $callback)
		780	Call the callback when the embedded event loop ($otherloop) has any
		781	I/O activity. The $callback should alwas be specified as "undef" in
		782	this version of EV, which means the embedded event loop will be
		783	managed automatically.
		784
		785	The "embed_ns" variant doesn't start (activate) the newly created
		786	watcher.
		787
		788	ASYNC WATCHERS - how to wake up another event loop
		789	Async watchers are provided by EV, but have little use in perl directly,
		790	as perl neither supports threads nor direct access to signal handlers or
		791	other contexts where they could be of value.
		792
		793	It is, however, possible to use them from the XS level.
		794
		795	Please see the libev documentation for further details.
		796
		797	$w = EV::async $callback
		798	$w = EV::async_ns $callback
		799	$w->send
		800	$bool = $w->async_pending
		801
		802	PERL SIGNALS
		803	While Perl signal handling (%SIG) is not affected by EV, the behaviour
		804	with EV is as the same as any other C library: Perl-signals will only be
		805	handled when Perl runs, which means your signal handler might be invoked
		806	only the next time an event callback is invoked.
		807
		808	The solution is to use EV signal watchers (see "EV::signal"), which will
		809	ensure proper operations with regards to other event watchers.
		810
		811	If you cannot do this for whatever reason, you can also force a watcher
		812	to be called on every event loop iteration by installing a "EV::check"
		813	watcher:
		814
		815	my $async_check = EV::check sub { };
		816
		817	This ensures that perl gets into control for a short time to handle any
		818	pending signals, and also ensures (slightly) slower overall operation.
615		819
616	THREADS	820	THREADS
617	Threads are not supported by this module in any way. Perl pseudo-threads	821	Threads are not supported by this module in any way. Perl pseudo-threads
618	is evil stuff and must die. As soon as Perl gains real threads I will	822	is evil stuff and must die. As soon as Perl gains real threads I will
619	work on thread support for it.	823	work on thread support for it.
…		…
634		838
635	On win32, there is no notion of fork so all this doesn't apply, of	839	On win32, there is no notion of fork so all this doesn't apply, of
636	course.	840	course.
637		841
638	SEE ALSO	842	SEE ALSO
639	EV::ADNS (asynchronous dns), Glib::EV (makes Glib/Gtk2 use EV as event	843	EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
640	loop), Coro::EV (efficient coroutines with EV).	844	loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
		845	with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
		846	agnostic and portable event driven programming.
641		847
642	AUTHOR	848	AUTHOR
643	Marc Lehmann <schmorp@schmorp.de>	849	Marc Lehmann <schmorp@schmorp.de>
644	http://home.schmorp.de/	850	http://home.schmorp.de/
645		851

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Comparing EV/README (file contents): Revision 1.15 by root, Wed Dec 5 14:06:50 2007 UTC vs. Revision 1.25 by root, Sun May 18 10:45:36 2008 UTC

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Comparing EV/README (file contents):
Revision 1.15 by root, Wed Dec 5 14:06:50 2007 UTC vs.
Revision 1.25 by root, Sun May 18 10:45:36 2008 UTC