[ViewVC] Diff of: cvs/EV/README

Comparing EV/README (file contents):
Revision 1.16 by root, Fri Dec 7 18:11:23 2007 UTC vs.
Revision 1.27 by root, Mon May 26 05:37:18 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", or just	61	available backends, or how to force a specific backend with
62	about in any case because it has much more detailed information.	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 function automatically, at
		102	some performance loss (refer to the libev documentation).
		103
		104	$loop->loop_verify
		105	Calls "ev_verify" to make internal consistency checks (for debugging
		106	libev) and abort the program if any data structures wree found to be
		107	corrupted.
		108
		109	$loop = EV::default_loop [$flags]
		110	Return the default loop (which is a singleton object). Since this
		111	module already creates the default loop with default flags,
		112	specifying flags here will not have any effect unless you destroy
		113	the default loop.
63		114
64	BASIC INTERFACE	115	BASIC INTERFACE
65	$EV::DIED	116	$EV::DIED
66	Must contain a reference to a function that is called when a	117	Must contain a reference to a function that is called when a
67	callback throws an exception (with $@ containing thr error). The	118	callback throws an exception (with $@ containing the error). The
68	default prints an informative message and continues.	119	default prints an informative message and continues.
69		120
70	If this callback throws an exception it will be silently ignored.	121	If this callback throws an exception it will be silently ignored.
		122
		123	$flags = EV::supported_backends
		124	$flags = EV::recommended_backends
		125	$flags = EV::embeddable_backends
		126	Returns the set (see "EV::BACKEND_*" flags) of backends supported by
		127	this instance of EV, the set of recommended backends (supposed to be
		128	good) for this platform and the set of embeddable backends (see
		129	EMBED WATCHERS).
		130
		131	EV::sleep $seconds
		132	Block the process for the given number of (fractional) seconds.
71		133
72	$time = EV::time	134	$time = EV::time
73	Returns the current time in (fractional) seconds since the epoch.	135	Returns the current time in (fractional) seconds since the epoch.
74		136
75	$time = EV::now	137	$time = EV::now
		138	$time = $loop->now
76	Returns the time the last event loop iteration has been started.	139	Returns the time the last event loop iteration has been started.
77	This is the time that (relative) timers are based on, and refering	140	This is the time that (relative) timers are based on, and refering
78	to it is usually faster then calling EV::time.	141	to it is usually faster then calling EV::time.
79		142
80	$method = EV::method	143	$backend = EV::backend
		144	$backend = $loop->backend
81	Returns an integer describing the backend used by libev	145	Returns an integer describing the backend used by libev
82	(EV::METHOD_SELECT or EV::METHOD_EPOLL).	146	(EV::METHOD_SELECT or EV::METHOD_EPOLL).
83		147
84	EV::loop [$flags]	148	EV::loop [$flags]
		149	$loop->loop ([$flags])
85	Begin checking for events and calling callbacks. It returns when a	150	Begin checking for events and calling callbacks. It returns when a
86	callback calls EV::unloop.	151	callback calls EV::unloop.
87		152
88	The $flags argument can be one of the following:	153	The $flags argument can be one of the following:
89		154
90	0 as above	155	0 as above
91	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	156	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
92	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	157	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
93		158
94	EV::unloop [$how]	159	EV::unloop [$how]
		160	$loop->unloop ([$how])
95	When called with no arguments or an argument of EV::UNLOOP_ONE,	161	When called with no arguments or an argument of EV::UNLOOP_ONE,
96	makes the innermost call to EV::loop return.	162	makes the innermost call to EV::loop return.
97		163
98	When called with an argument of EV::UNLOOP_ALL, all calls to	164	When called with an argument of EV::UNLOOP_ALL, all calls to
99	EV::loop will return as fast as possible.	165	EV::loop will return as fast as possible.
100		166
101	$count = EV::loop_count	167	$count = EV::loop_count
		168	$count = $loop->loop_count
102	Return the number of times the event loop has polled for new events.	169	Return the number of times the event loop has polled for new events.
103	Sometiems useful as a generation counter.	170	Sometiems useful as a generation counter.
104		171
105	EV::once $fh_or_undef, $events, $timeout, $cb->($revents)	172	EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		173	$loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
106	This function rolls together an I/O and a timer watcher for a single	174	This function rolls together an I/O and a timer watcher for a single
107	one-shot event without the need for managing a watcher object.	175	one-shot event without the need for managing a watcher object.
108		176
109	If $fh_or_undef is a filehandle or file descriptor, then $events	177	If $fh_or_undef is a filehandle or file descriptor, then $events
110	must be a bitset containing either "EV::READ", "EV::WRITE" or	178	must be a bitset containing either "EV::READ", "EV::WRITE" or
…		…
115	If timeout is "undef" or negative, then there will be no timeout.	183	If timeout is "undef" or negative, then there will be no timeout.
116	Otherwise a EV::timer with this value will be started.	184	Otherwise a EV::timer with this value will be started.
117		185
118	When an error occurs or either the timeout or I/O watcher triggers,	186	When an error occurs or either the timeout or I/O watcher triggers,
119	then the callback will be called with the received event set (in	187	then the callback will be called with the received event set (in
120	general you can expect it to be a combination of "EV:ERROR",	188	general you can expect it to be a combination of "EV::ERROR",
121	"EV::READ", "EV::WRITE" and "EV::TIMEOUT").	189	"EV::READ", "EV::WRITE" and "EV::TIMEOUT").
122		190
123	EV::once doesn't return anything: the watchers stay active till	191	EV::once doesn't return anything: the watchers stay active till
124	either of them triggers, then they will be stopped and freed, and	192	either of them triggers, then they will be stopped and freed, and
125	the callback invoked.	193	the callback invoked.
126		194
		195	EV::feed_fd_event ($fd, $revents)
		196	$loop->feed_fd_event ($fd, $revents)
		197	Feed an event on a file descriptor into EV. EV will react to this
		198	call as if the readyness notifications specified by $revents (a
		199	combination of "EV::READ" and "EV::WRITE") happened on the file
		200	descriptor $fd.
		201
		202	EV::feed_signal_event ($signal)
		203	Feed a signal event into EV. EV will react to this call as if the
		204	signal specified by $signal had occured.
		205
		206	EV::set_io_collect_interval $time
		207	$loop->set_io_collect_interval ($time)
		208	EV::set_timeout_collect_interval $time
		209	$loop->set_timeout_collect_interval ($time)
		210	These advanced functions set the minimum block interval when polling
		211	for I/O events and the minimum wait interval for timer events. See
		212	the libev documentation at
		213	<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
		214	ROLLING_THE_EVENT_LOOP> for a more detailed discussion.
		215
127	WATCHER OBJECTS	216	WATCHER OBJECTS
128	A watcher is an object that gets created to record your interest in some	217	A watcher is an object that gets created to record your interest in some
129	event. For instance, if you want to wait for STDIN to become readable,	218	event. For instance, if you want to wait for STDIN to become readable,
130	you would create an EV::io watcher for that:	219	you would create an EV::io watcher for that:
131		220
132	my $watcher = EV::io *STDIN, EV::READ, sub {	221	my $watcher = EV::io *STDIN, EV::READ, sub {
133	my ($watcher, $revents) = @_;	222	my ($watcher, $revents) = @_;
134	warn "yeah, STDIN should not be readable without blocking!\n"	223	warn "yeah, STDIN should now be readable without blocking!\n"
135	};	224	};
136		225
137	All watchers can be active (waiting for events) or inactive (paused).	226	All watchers can be active (waiting for events) or inactive (paused).
138	Only active watchers will have their callbacks invoked. All callbacks	227	Only active watchers will have their callbacks invoked. All callbacks
139	will be called with at least two arguments: the watcher and a bitmask of	228	will be called with at least two arguments: the watcher and a bitmask of
…		…
202	The default priority of any newly-created watcher is 0.	291	The default priority of any newly-created watcher is 0.
203		292
204	Note that the priority semantics have not yet been fleshed out and	293	Note that the priority semantics have not yet been fleshed out and
205	are subject to almost certain change.	294	are subject to almost certain change.
206		295
207	$w->trigger ($revents)	296	$w->invoke ($revents)
208	Call the callback now with the given event mask.	297	Call the callback now with the given event mask.
		298
		299	$w->feed_event ($revents)
		300	Feed some events on this watcher into EV. EV will react to this call
		301	as if the watcher had received the given $revents mask.
		302
		303	$revents = $w->clear_pending
		304	If the watcher is pending, this function clears its pending status
		305	and returns its $revents bitset (as if its callback was invoked). If
		306	the watcher isn't pending it does nothing and returns 0.
209		307
210	$previous_state = $w->keepalive ($bool)	308	$previous_state = $w->keepalive ($bool)
211	Normally, "EV::loop" will return when there are no active watchers	309	Normally, "EV::loop" will return when there are no active watchers
212	(which is a "deadlock" because no progress can be made anymore).	310	(which is a "deadlock" because no progress can be made anymore).
213	This is convinient because it allows you to start your watchers (and	311	This is convinient because it allows you to start your watchers (and
214	your jobs), call "EV::loop" once and when it returns you know that	312	your jobs), call "EV::loop" once and when it returns you know that
215	all your jobs are finished (or they forgot to register some watchers	313	all your jobs are finished (or they forgot to register some watchers
216	for their task :).	314	for their task :).
217		315
218	Sometimes, however, this gets in your way, for example when you the	316	Sometimes, however, this gets in your way, for example when the
219	module that calls "EV::loop" (usually the main program) is not the	317	module that calls "EV::loop" (usually the main program) is not the
220	same module as a long-living watcher (for example a DNS client	318	same module as a long-living watcher (for example a DNS client
221	module written by somebody else even). Then you might want any	319	module written by somebody else even). Then you might want any
222	outstanding requests to be handled, but you would not want to keep	320	outstanding requests to be handled, but you would not want to keep
223	"EV::loop" from returning just because you happen to have this	321	"EV::loop" from returning just because you happen to have this
…		…
233	Example: Register an I/O watcher for some UDP socket but do not keep	331	Example: Register an I/O watcher for some UDP socket but do not keep
234	the event loop from running just because of that watcher.	332	the event loop from running just because of that watcher.
235		333
236	my $udp_socket = ...	334	my $udp_socket = ...
237	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };	335	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
238	$udp_watcher->keepalive (0);	336	$1000udp_watcher->keepalive (0);
239		337
		338	$loop = $w->loop
		339	Return the loop that this watcher is attached to.
		340
240	WATCHER TYPES	341	WATCHER TYPES
241	Each of the following subsections describes a single watcher type.	342	Each of the following subsections describes a single watcher type.
242		343
243	I/O WATCHERS - is this file descriptor readable or writable?	344	I/O WATCHERS - is this file descriptor readable or writable?
244	$w = EV::io $fileno_or_fh, $eventmask, $callback	345	$w = EV::io $fileno_or_fh, $eventmask, $callback
245	$w = EV::io_ns $fileno_or_fh, $eventmask, $callback	346	$w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		347	$w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		348	$w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
246	As long as the returned watcher object is alive, call the $callback	349	As long as the returned watcher object is alive, call the $callback
247	when at least one of events specified in $eventmask occurs.	350	when at least one of events specified in $eventmask occurs.
248		351
249	The $eventmask can be one or more of these constants ORed together:	352	The $eventmask can be one or more of these constants ORed together:
250		353
…		…
267	Returns the previously set event mask and optionally set a new one.	370	Returns the previously set event mask and optionally set a new one.
268		371
269	TIMER WATCHERS - relative and optionally repeating timeouts	372	TIMER WATCHERS - relative and optionally repeating timeouts
270	$w = EV::timer $after, $repeat, $callback	373	$w = EV::timer $after, $repeat, $callback
271	$w = EV::timer_ns $after, $repeat, $callback	374	$w = EV::timer_ns $after, $repeat, $callback
		375	$w = $loop->timer ($after, $repeat, $callback)
		376	$w = $loop->timer_ns ($after, $repeat, $callback)
272	Calls the callback after $after seconds (which may be fractional).	377	Calls the callback after $after seconds (which may be fractional).
273	If $repeat is non-zero, the timer will be restarted (with the	378	If $repeat is non-zero, the timer will be restarted (with the
274	$repeat value as $after) after the callback returns.	379	$repeat value as $after) after the callback returns.
275		380
276	This means that the callback would be called roughly after $after	381	This means that the callback would be called roughly after $after
…		…
312	method on the timeout.	417	method on the timeout.
313		418
314	PERIODIC WATCHERS - to cron or not to cron?	419	PERIODIC WATCHERS - to cron or not to cron?
315	$w = EV::periodic $at, $interval, $reschedule_cb, $callback	420	$w = EV::periodic $at, $interval, $reschedule_cb, $callback
316	$w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	421	$w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		422	$w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		423	$w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
317	Similar to EV::timer, but is not based on relative timeouts but on	424	Similar to EV::timer, but is not based on relative timeouts but on
318	absolute times. Apart from creating "simple" timers that trigger	425	absolute times. Apart from creating "simple" timers that trigger
319	"at" the specified time, it can also be used for non-drifting	426	"at" the specified time, it can also be used for non-drifting
320	absolute timers and more complex, cron-like, setups that are not	427	absolute timers and more complex, cron-like, setups that are not
321	adversely affected by time jumps (i.e. when the system clock is	428	adversely affected by time jumps (i.e. when the system clock is
322	changed by explicit date -s or other means such as ntpd). It is also	429	changed by explicit date -s or other means such as ntpd). It is also
323	the most complex watcher type in EV.	430	the most complex watcher type in EV.
324		431
325	It has three distinct "modes":	432	It has three distinct "modes":
326		433
327	* absolute timer ($interval = $reschedule_cb = 0)	434	* absolute timer ($interval = $reschedule_cb = 0)
		435
328	This time simply fires at the wallclock time $at and doesn't	436	This time simply fires at the wallclock time $at and doesn't
329	repeat. It will not adjust when a time jump occurs, that is, if	437	repeat. It will not adjust when a time jump occurs, that is, if
330	it is to be run at January 1st 2011 then it will run when the	438	it is to be run at January 1st 2011 then it will run when the
331	system time reaches or surpasses this time.	439	system time reaches or surpasses this time.
332		440
333	* non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	441	* repeating interval timer ($interval > 0, $reschedule_cb = 0)
		442
334	In this mode the watcher will always be scheduled to time out at	443	In this mode the watcher will always be scheduled to time out at
335	the next "$at + N * $interval" time (for some integer N) and	444	the next "$at + N * $interval" time (for some integer N) and
336	then repeat, regardless of any time jumps.	445	then repeat, regardless of any time jumps.
337		446
338	This can be used to create timers that do not drift with respect	447	This can be used to create timers that do not drift with respect
…		…
347	Another way to think about it (for the mathematically inclined)	456	Another way to think about it (for the mathematically inclined)
348	is that EV::periodic will try to run the callback in this mode	457	is that EV::periodic will try to run the callback in this mode
349	at the next possible time where "$time = $at (mod $interval)",	458	at the next possible time where "$time = $at (mod $interval)",
350	regardless of any time jumps.	459	regardless of any time jumps.
351		460
352	* manual reschedule mode ($reschedule_cb = coderef)	461	* manual reschedule mode ($reschedule_cb = coderef)
		462
353	In this mode $interval and $at are both being ignored. Instead,	463	In this mode $interval and $at are both being ignored. Instead,
354	each time the periodic watcher gets scheduled, the reschedule	464	each time the periodic watcher gets scheduled, the reschedule
355	callback ($reschedule_cb) will be called with the watcher as	465	callback ($reschedule_cb) will be called with the watcher as
356	first, and the current time as second argument.	466	first, and the current time as second argument.
357		467
358	*This callback MUST NOT stop or destroy this or any other	468	*This callback MUST NOT stop or destroy this or any other
		469	periodic watcher, ever, and MUST NOT call any event loop
359	periodic watcher, ever*. If you need to stop it, return 1e30 and	470	functions or methods*. If you need to stop it, return 1e30 and
360	stop it afterwards.	471	stop it afterwards. You may create and start a "EV::prepare"
		472	watcher for this task.
361		473
362	It must return the next time to trigger, based on the passed	474	It must return the next time to trigger, based on the passed
363	time value (that is, the lowest time value larger than to the	475	time value (that is, the lowest time value larger than or equal
364	second argument). It will usually be called just before the	476	to to the second argument). It will usually be called just
365	callback will be triggered, but might be called at other times,	477	before the callback will be triggered, but might be called at
366	too.	478	other times, too.
367		479
368	This can be used to create very complex timers, such as a timer	480	This can be used to create very complex timers, such as a timer
369	that triggers on each midnight, local time (actually 24 hours	481	that triggers on each midnight, local time (actually 24 hours
370	after the last midnight, to keep the example simple. If you know	482	after the last midnight, to keep the example simple. If you know
371	a way to do it correctly in about the same space (without	483	a way to do it correctly in about the same space (without
…		…
389	be called at any time.	501	be called at any time.
390		502
391	$w->again	503	$w->again
392	Simply stops and starts the watcher again.	504	Simply stops and starts the watcher again.
393		505
		506	$time = $w->at
		507	Return the time that the watcher is expected to trigger next.
		508
394	SIGNAL WATCHERS - signal me when a signal gets signalled!	509	SIGNAL WATCHERS - signal me when a signal gets signalled!
395	$w = EV::signal $signal, $callback	510	$w = EV::signal $signal, $callback
396	$w = EV::signal_ns $signal, $callback	511	$w = EV::signal_ns $signal, $callback
397	Call the callback when $signal is received (the signal can be	512	Call the callback when $signal is received (the signal can be
398	specified by number or by name, just as with "kill" or %SIG).	513	specified by number or by name, just as with "kill" or %SIG).
…		…
415	$old_signum = $w->signal ($new_signal)	530	$old_signum = $w->signal ($new_signal)
416	Returns the previously set signal (always as a number not name) and	531	Returns the previously set signal (always as a number not name) and
417	optionally set a new one.	532	optionally set a new one.
418		533
419	CHILD WATCHERS - watch out for process status changes	534	CHILD WATCHERS - watch out for process status changes
420	$w = EV::child $pid, $callback	535	$w = EV::child $pid, $trace, $callback
421	$w = EV::child_ns $pid, $callback	536	$w = EV::child_ns $pid, $trace, $callback
		537	$w = $loop->child ($pid, $trace, $callback)
		538	$w = $loop->child_ns ($pid, $trace, $callback)
422	Call the callback when a status change for pid $pid (or any pid if	539	Call the callback when a status change for pid $pid (or any pid if
423	$pid is 0) has been received. More precisely: when the process	540	$pid is 0) has been received (a status change happens when the
		541	process terminates or is killed, or, when trace is true,
		542	additionally when it is stopped or continued). More precisely: when
424	receives a "SIGCHLD", EV will fetch the outstanding exit/wait status	543	the process receives a "SIGCHLD", EV will fetch the outstanding
425	for all changed/zombie children and call the callback.	544	exit/wait status for all changed/zombie children and call the
		545	callback.
426		546
427	It is valid (and fully supported) to install a child watcher after a	547	It is valid (and fully supported) to install a child watcher after a
428	child has exited but before the event loop has started its next	548	child has exited but before the event loop has started its next
429	iteration (for example, first you "fork", then the new child process	549	iteration (for example, first you "fork", then the new child process
430	might exit, and only then do you install a child watcher in the	550	might exit, and only then do you install a child watcher in the
…		…
437	be called.	557	be called.
438		558
439	The "child_ns" variant doesn't start (activate) the newly created	559	The "child_ns" variant doesn't start (activate) the newly created
440	watcher.	560	watcher.
441		561
442	$w->set ($pid)	562	$w->set ($pid, $trace)
443	Reconfigures the watcher, see the constructor above for details. Can	563	Reconfigures the watcher, see the constructor above for details. Can
444	be called at any time.	564	be called at any time.
445		565
446	$current_pid = $w->pid	566	$current_pid = $w->pid
447	$old_pid = $w->pid ($new_pid)
448	Returns the previously set process id and optionally set a new one.	567	Returns the previously set process id and optionally set a new one.
449		568
450	$exit_status = $w->rstatus	569	$exit_status = $w->rstatus
451	Return the exit/wait status (as returned by waitpid, see the waitpid	570	Return the exit/wait status (as returned by waitpid, see the waitpid
452	entry in perlfunc).	571	entry in perlfunc).
…		…
456	a watcher for all pids).	575	a watcher for all pids).
457		576
458	STAT WATCHERS - did the file attributes just change?	577	STAT WATCHERS - did the file attributes just change?
459	$w = EV::stat $path, $interval, $callback	578	$w = EV::stat $path, $interval, $callback
460	$w = EV::stat_ns $path, $interval, $callback	579	$w = EV::stat_ns $path, $interval, $callback
		580	$w = $loop->stat ($path, $interval, $callback)
		581	$w = $loop->stat_ns ($path, $interval, $callback)
461	Call the callback when a file status change has been detected on	582	Call the callback when a file status change has been detected on
462	$path. The $path does not need to exist, changing from "path exists"	583	$path. The $path does not need to exist, changing from "path exists"
463	to "path does not exist" is a status change like any other.	584	to "path does not exist" is a status change like any other.
464		585
465	The $interval is a recommended polling interval for systems where	586	The $interval is a recommended polling interval for systems where
…		…
525	Can be used to query the actual interval used.	646	Can be used to query the actual interval used.
526		647
527	IDLE WATCHERS - when you've got nothing better to do...	648	IDLE WATCHERS - when you've got nothing better to do...
528	$w = EV::idle $callback	649	$w = EV::idle $callback
529	$w = EV::idle_ns $callback	650	$w = EV::idle_ns $callback
		651	$w = $loop->idle ($callback)
		652	$w = $loop->idle_ns ($callback)
530	Call the callback when there are no other pending watchers of the	653	Call the callback when there are no other pending watchers of the
531	same or higher priority (excluding check, prepare and other idle	654	same or higher priority (excluding check, prepare and other idle
532	watchers of the same or lower priority, of course). They are called	655	watchers of the same or lower priority, of course). They are called
533	idle watchers because when the watcher is the highest priority	656	idle watchers because when the watcher is the highest priority
534	pending event in the process, the process is considered to be idle	657	pending event in the process, the process is considered to be idle
…		…
550	watcher.	673	watcher.
551		674
552	PREPARE WATCHERS - customise your event loop!	675	PREPARE WATCHERS - customise your event loop!
553	$w = EV::prepare $callback	676	$w = EV::prepare $callback
554	$w = EV::prepare_ns $callback	677	$w = EV::prepare_ns $callback
		678	$w = $loop->prepare ($callback)
		679	$w = $loop->prepare_ns ($callback)
555	Call the callback just before the process would block. You can still	680	Call the callback just before the process would block. You can still
556	create/modify any watchers at this point.	681	create/modify any watchers at this point.
557		682
558	See the EV::check watcher, below, for explanations and an example.	683	See the EV::check watcher, below, for explanations and an example.
559		684
…		…
561	watcher.	686	watcher.
562		687
563	CHECK WATCHERS - customise your event loop even more!	688	CHECK WATCHERS - customise your event loop even more!
564	$w = EV::check $callback	689	$w = EV::check $callback
565	$w = EV::check_ns $callback	690	$w = EV::check_ns $callback
		691	$w = $loop->check ($callback)
		692	$w = $loop->check_ns ($callback)
566	Call the callback just after the process wakes up again (after it	693	Call the callback just after the process wakes up again (after it
567	has gathered events), but before any other callbacks have been	694	has gathered events), but before any other callbacks have been
568	invoked.	695	invoked.
569		696
570	This is used to integrate other event-based software into the EV	697	This is used to integrate other event-based software into the EV
…		…
619	is done before the event loop blocks next and before "check" watchers	746	is done before the event loop blocks next and before "check" watchers
620	are being called, and only in the child after the fork.	747	are being called, and only in the child after the fork.
621		748
622	$w = EV::fork $callback	749	$w = EV::fork $callback
623	$w = EV::fork_ns $callback	750	$w = EV::fork_ns $callback
		751	$w = $loop->fork ($callback)
		752	$w = $loop->fork_ns ($callback)
624	Call the callback before the event loop is resumed in the child	753	Call the callback before the event loop is resumed in the child
625	process after a fork.	754	process after a fork.
626		755
627	The "fork_ns" variant doesn't start (activate) the newly created	756	The "fork_ns" variant doesn't start (activate) the newly created
628	watcher.	757	watcher.
		758
		759	EMBED WATCHERS - when one backend isn't enough...
		760	This is a rather advanced watcher type that lets you embed one event
		761	loop into another (currently only IO events are supported in the
		762	embedded loop, other types of watchers might be handled in a delayed or
		763	incorrect fashion and must not be used).
		764
		765	See the libev documentation at
		766	<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code
		767	_when_one_backend_> for more details.
		768
		769	In short, this watcher is most useful on BSD systems without working
		770	kqueue to still be able to handle a large number of sockets:
		771
		772	my $socket_loop;
		773
		774	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		775	if (
		776	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		777	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		778	) {
		779	# use kqueue for sockets
		780	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		781	}
		782
		783	# use the default loop otherwise
		784	$socket_loop \|\|= EV::default_loop;
		785
		786	$w = EV::embed $otherloop, $callback
		787	$w = EV::embed_ns $otherloop, $callback
		788	$w = $loop->embed ($otherloop, $callback)
		789	$w = $loop->embed_ns ($otherloop, $callback)
		790	Call the callback when the embedded event loop ($otherloop) has any
		791	I/O activity. The $callback should alwas be specified as "undef" in
		792	this version of EV, which means the embedded event loop will be
		793	managed automatically.
		794
		795	The "embed_ns" variant doesn't start (activate) the newly created
		796	watcher.
		797
		798	ASYNC WATCHERS - how to wake up another event loop
		799	Async watchers are provided by EV, but have little use in perl directly,
		800	as perl neither supports threads nor direct access to signal handlers or
		801	other contexts where they could be of value.
		802
		803	It is, however, possible to use them from the XS level.
		804
		805	Please see the libev documentation for further details.
		806
		807	$w = EV::async $callback
		808	$w = EV::async_ns $callback
		809	$w->send
		810	$bool = $w->async_pending
629		811
630	PERL SIGNALS	812	PERL SIGNALS
631	While Perl signal handling (%SIG) is not affected by EV, the behaviour	813	While Perl signal handling (%SIG) is not affected by EV, the behaviour
632	with EV is as the same as any other C library: Perl-signals will only be	814	with EV is as the same as any other C library: Perl-signals will only be
633	handled when Perl runs, which means your signal handler might be invoked	815	handled when Perl runs, which means your signal handler might be invoked
…		…
640	to be called on every event loop iteration by installing a "EV::check"	822	to be called on every event loop iteration by installing a "EV::check"
641	watcher:	823	watcher:
642		824
643	my $async_check = EV::check sub { };	825	my $async_check = EV::check sub { };
644		826
645	This ensures that perl shortly gets into control for a short time, and	827	This ensures that perl gets into control for a short time to handle any
646	also ensures slower overall operation.	828	pending signals, and also ensures (slightly) slower overall operation.
647		829
648	THREADS	830	THREADS
649	Threads are not supported by this module in any way. Perl pseudo-threads	831	Threads are not supported by this module in any way. Perl pseudo-threads
650	is evil stuff and must die. As soon as Perl gains real threads I will	832	is evil stuff and must die. As soon as Perl gains real threads I will
651	work on thread support for it.	833	work on thread support for it.
…		…
666		848
667	On win32, there is no notion of fork so all this doesn't apply, of	849	On win32, there is no notion of fork so all this doesn't apply, of
668	course.	850	course.
669		851
670	SEE ALSO	852	SEE ALSO
671	EV::ADNS (asynchronous dns), Glib::EV (makes Glib/Gtk2 use EV as event	853	EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event
672	loop), Coro::EV (efficient coroutines with EV).	854	loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines
		855	with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop
		856	agnostic and portable event driven programming.
673		857
674	AUTHOR	858	AUTHOR
675	Marc Lehmann <schmorp@schmorp.de>	859	Marc Lehmann <schmorp@schmorp.de>
676	http://home.schmorp.de/	860	http://home.schmorp.de/
677		861

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Comparing EV/README (file contents): Revision 1.16 by root, Fri Dec 7 18:11:23 2007 UTC vs. Revision 1.27 by root, Mon May 26 05:37:18 2008 UTC

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Comparing EV/README (file contents):
Revision 1.16 by root, Fri Dec 7 18:11:23 2007 UTC vs.
Revision 1.27 by root, Mon May 26 05:37:18 2008 UTC