[ViewVC] Diff of: cvs/EV/EV.pm

Comparing EV/EV.pm (file contents):
Revision 1.47 by root, Fri Nov 23 13:08:55 2007 UTC vs.
Revision 1.108 by root, Mon Nov 3 12:13:15 2008 UTC

…		…
2		2
3	EV - perl interface to libev, a high performance full-featured event loop	3	EV - perl interface to libev, a high performance full-featured event loop
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use EV;	7	use EV;
		8
		9	# TIMERS
		10
		11	my $w = EV::timer 2, 0, sub {
		12	warn "is called after 2s";
		13	};
		14
		15	my $w = EV::timer 2, 2, sub {
		16	warn "is called roughly every 2s (repeat = 2)";
		17	};
		18
		19	undef $w; # destroy event watcher again
		20
		21	my $w = EV::periodic 0, 60, 0, sub {
		22	warn "is called every minute, on the minute, exactly";
		23	};
		24
		25	# IO
		26
		27	my $w = EV::io *STDIN, EV::READ, sub {
		28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
		29	warn "stdin is readable, you entered: ", <STDIN>;
		30	};
		31
		32	# SIGNALS
		33
		34	my $w = EV::signal 'QUIT', sub {
		35	warn "sigquit received\n";
		36	};
		37
		38	# CHILD/PID STATUS CHANGES
8		39
9	# TIMERS	40	my $w = EV::child 666, 0, sub {
		41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
		43	};
10		44
11	my $w = EV::timer 2, 0, sub {	45	# STAT CHANGES
12	warn "is called after 2s";	46	my $w = EV::stat "/etc/passwd", 10, sub {
13	};
14
15	my $w = EV::timer 2, 2, sub {
16	warn "is called roughly every 2s (repeat = 2)";
17	};
18
19	undef $w; # destroy event watcher again
20
21	my $w = EV::periodic 0, 60, 0, sub {
22	warn "is called every minute, on the minute, exactly";
23	};
24
25	# IO
26
27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29	warn "stdin is readable, you entered: ", <STDIN>;
30	};
31
32	# SIGNALS
33
34	my $w = EV::signal 'QUIT', sub {
35	warn "sigquit received\n";
36	};
37
38	# CHILD/PID STATUS CHANGES
39
40	my $w = EV::child 666, sub {
41	my ($w, $revents) = @_;	47	my ($w, $revents) = @_;
42	my $status = $w->rstatus;	48	warn $w->path, " has changed somehow.\n";
43	};	49	};
44		50
45	# MAINLOOP	51	# MAINLOOP
46	EV::loop; # loop until EV::unloop is called or all watchers stop	52	EV::loop; # loop until EV::unloop is called or all watchers stop
47	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
48	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
49		55
50	=head1 DESCRIPTION	56	=head1 DESCRIPTION
51		57
52	This module provides an interface to libev	58	This module provides an interface to libev
53	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of
		61	libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
		62	F<perldoc EV::libev>) for more subtle details on watcher semantics or some
		63	discussion on the available backends, or how to force a specific backend
		64	with C<LIBEV_FLAGS>, or just about in any case because it has much more
		65	detailed information.
		66
		67	This module is very fast and scalable. It is actually so fast that you
		68	can use it through the L<AnyEvent> module, stay portable to other event
		69	loops (if you don't rely on any watcher types not available through it)
		70	and still be faster than with any other event loop currently supported in
		71	Perl.
		72
		73	=head2 MODULE EXPORTS
		74
		75	This module does not export any symbols.
54		76
55	=cut	77	=cut
56		78
57	package EV;	79	package EV;
58		80
		81	no warnings;
59	use strict;	82	use strict;
60		83
61	BEGIN {	84	BEGIN {
62	our $VERSION = '1.2';	85	our $VERSION = '3.48';
63	use XSLoader;	86	use XSLoader;
64	XSLoader::load "EV", $VERSION;	87	XSLoader::load "EV", $VERSION;
65	}	88	}
66		89
67	@EV::Io::ISA =	90	@EV::IO::ISA =
68	@EV::Timer::ISA =	91	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	92	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	93	@EV::Signal::ISA =
		94	@EV::Child::ISA =
		95	@EV::Stat::ISA =
71	@EV::Idle::ISA =	96	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	97	@EV::Prepare::ISA =
73	@EV::Check::ISA =	98	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	99	@EV::Embed::ISA =
		100	@EV::Fork::ISA =
		101	@EV::Async::ISA =
		102	"EV::Watcher";
		103
		104	@EV::Loop::Default::ISA = "EV::Loop";
		105
		106	=head1 EVENT LOOPS
		107
		108	EV supports multiple event loops: There is a single "default event loop"
		109	that can handle everything including signals and child watchers, and any
		110	number of "dynamic event loops" that can use different backends (with
		111	various limitations), but no child and signal watchers.
		112
		113	You do not have to do anything to create the default event loop: When
		114	the module is loaded a suitable backend is selected on the premise of
		115	selecting a working backend (which for example rules out kqueue on most
		116	BSDs). Modules should, unless they have "special needs" always use the
		117	default loop as this is fastest (perl-wise), best supported by other
		118	modules (e.g. AnyEvent or Coro) and most portable event loop.
		119
		120	For specific programs you can create additional event loops dynamically.
		121
		122	If you want to take advantage of kqueue (which often works properly for
		123	sockets only) even though the default loop doesn't enable it, you can
		124	I<embed> a kqueue loop into the default loop: running the default loop
		125	will then also service the kqueue loop to some extent. See the example in
		126	the section about embed watchers for an example on how to achieve that.
		127
		128	=over 4
		129
		130	=item $loop = new EV::loop [$flags]
		131
		132	Create a new event loop as per the specified flags. Please refer to
		133	the C<ev_loop_new ()> function description in the libev documentation
		134	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
		135	or locally-installed as F<EV::libev> manpage) for more info.
		136
		137	The loop will automatically be destroyed when it is no longer referenced
		138	by any watcher and the loop object goes out of scope.
		139
		140	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		141	is recommended, as only the default event loop is protected by this
		142	module. If you I<are> embedding this loop in the default loop, this is not
		143	necessary, as C<EV::embed> automatically does the right thing on fork.
		144
		145	=item $loop->loop_fork
		146
		147	Must be called after a fork in the child, before entering or continuing
		148	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		149	this function automatically, at some performance loss (refer to the libev
		150	documentation).
		151
		152	=item $loop->loop_verify
		153
		154	Calls C<ev_verify> to make internal consistency checks (for debugging
		155	libev) and abort the program if any data structures were found to be
		156	corrupted.
		157
		158	=item $loop = EV::default_loop [$flags]
		159
		160	Return the default loop (which is a singleton object). Since this module
		161	already creates the default loop with default flags, specifying flags here
		162	will not have any effect unless you destroy the default loop first, which
		163	isn't supported. So in short: don't do it, and if you break it, you get to
		164	keep the pieces.
		165
		166	=back
		167
75		168
76	=head1 BASIC INTERFACE	169	=head1 BASIC INTERFACE
77		170
78	=over 4	171	=over 4
79		172
80	=item $EV::DIED	173	=item $EV::DIED
81		174
82	Must contain a reference to a function that is called when a callback	175	Must contain a reference to a function that is called when a callback
83	throws an exception (with $@ containing thr error). The default prints an	176	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	177	informative message and continues.
85		178
86	If this callback throws an exception it will be silently ignored.	179	If this callback throws an exception it will be silently ignored.
87		180
		181	=item $flags = EV::supported_backends
		182
		183	=item $flags = EV::recommended_backends
		184
		185	=item $flags = EV::embeddable_backends
		186
		187	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		188	instance of EV, the set of recommended backends (supposed to be good) for
		189	this platform and the set of embeddable backends (see EMBED WATCHERS).
		190
		191	=item EV::sleep $seconds
		192
		193	Block the process for the given number of (fractional) seconds.
		194
88	=item $time = EV::time	195	=item $time = EV::time
89		196
90	Returns the current time in (fractional) seconds since the epoch.	197	Returns the current time in (fractional) seconds since the epoch.
91		198
92	=item $time = EV::now	199	=item $time = EV::now
93		200
		201	=item $time = $loop->now
		202
94	Returns the time the last event loop iteration has been started. This	203	Returns the time the last event loop iteration has been started. This
95	is the time that (relative) timers are based on, and refering to it is	204	is the time that (relative) timers are based on, and referring to it is
96	usually faster then calling EV::time.	205	usually faster then calling EV::time.
97		206
98	=item $method = EV::method	207	=item $backend = EV::backend
99		208
		209	=item $backend = $loop->backend
		210
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	211	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
101	or EV::METHOD_EPOLL).	212	or EV::BACKEND_EPOLL).
102		213
103	=item EV::loop [$flags]	214	=item EV::loop [$flags]
		215
		216	=item $loop->loop ([$flags])
104		217
105	Begin checking for events and calling callbacks. It returns when a	218	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	219	callback calls EV::unloop.
107		220
108	The $flags argument can be one of the following:	221	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	224	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	225	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		226
114	=item EV::unloop [$how]	227	=item EV::unloop [$how]
115		228
		229	=item $loop->unloop ([$how])
		230
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	231	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	232	innermost call to EV::loop return.
118		233
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	234	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	235	fast as possible.
121		236
		237	=item $count = EV::loop_count
		238
		239	=item $count = $loop->loop_count
		240
		241	Return the number of times the event loop has polled for new
		242	events. Sometimes useful as a generation counter.
		243
122	=item EV::once $fh_or_undef, $events, $timeout, $cb->($events)	244	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		245
		246	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
123		247
124	This function rolls together an I/O and a timer watcher for a single	248	This function rolls together an I/O and a timer watcher for a single
125	one-shot event without the need for managing a watcher object.	249	one-shot event without the need for managing a watcher object.
126		250
127	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>	251	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
…		…
133	If timeout is C<undef> or negative, then there will be no	257	If timeout is C<undef> or negative, then there will be no
134	timeout. Otherwise a EV::timer with this value will be started.	258	timeout. Otherwise a EV::timer with this value will be started.
135		259
136	When an error occurs or either the timeout or I/O watcher triggers, then	260	When an error occurs or either the timeout or I/O watcher triggers, then
137	the callback will be called with the received event set (in general	261	the callback will be called with the received event set (in general
138	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,	262	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
139	C<EV::WRITE> and C<EV::TIMEOUT>).	263	C<EV::WRITE> and C<EV::TIMEOUT>).
140		264
141	EV::once doesn't return anything: the watchers stay active till either	265	EV::once doesn't return anything: the watchers stay active till either
142	of them triggers, then they will be stopped and freed, and the callback	266	of them triggers, then they will be stopped and freed, and the callback
143	invoked.	267	invoked.
144		268
145	=back	269	=item EV::feed_fd_event ($fd, $revents)
146		270
147	=head2 WATCHER	271	=item $loop->feed_fd_event ($fd, $revents)
		272
		273	Feed an event on a file descriptor into EV. EV will react to this call as
		274	if the readyness notifications specified by C<$revents> (a combination of
		275	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		276
		277	=item EV::feed_signal_event ($signal)
		278
		279	Feed a signal event into EV. EV will react to this call as if the signal
		280	specified by C<$signal> had occured.
		281
		282	=item EV::set_io_collect_interval $time
		283
		284	=item $loop->set_io_collect_interval ($time)
		285
		286	=item EV::set_timeout_collect_interval $time
		287
		288	=item $loop->set_timeout_collect_interval ($time)
		289
		290	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		291	wait interval for timer events. See the libev documentation at
		292	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		293	(locally installed as F<EV::libev>) for a more detailed discussion.
		294
		295	=back
		296
		297
		298	=head1 WATCHER OBJECTS
148		299
149	A watcher is an object that gets created to record your interest in some	300	A watcher is an object that gets created to record your interest in some
150	event. For instance, if you want to wait for STDIN to become readable, you	301	event. For instance, if you want to wait for STDIN to become readable, you
151	would create an EV::io watcher for that:	302	would create an EV::io watcher for that:
152		303
153	my $watcher = EV::io *STDIN, EV::READ, sub {	304	my $watcher = EV::io *STDIN, EV::READ, sub {
154	my ($watcher, $revents) = @_;	305	my ($watcher, $revents) = @_;
155	warn "yeah, STDIN should not be readable without blocking!\n"	306	warn "yeah, STDIN should now be readable without blocking!\n"
156	};	307	};
157		308
158	All watchers can be active (waiting for events) or inactive (paused). Only	309	All watchers can be active (waiting for events) or inactive (paused). Only
159	active watchers will have their callbacks invoked. All callbacks will be	310	active watchers will have their callbacks invoked. All callbacks will be
160	called with at least two arguments: the watcher and a bitmask of received	311	called with at least two arguments: the watcher and a bitmask of received
161	events.	312	events.
162		313
163	Each watcher type has its associated bit in revents, so you can use the	314	Each watcher type has its associated bit in revents, so you can use the
164	same callback for multiple watchers. The event mask is named after the	315	same callback for multiple watchers. The event mask is named after the
165	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	316	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
166	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	317	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
167	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	318	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
168	uses EV::TIMEOUT).	319	uses EV::TIMEOUT).
169		320
170	In the rare case where one wants to create a watcher but not start it at	321	In the rare case where one wants to create a watcher but not start it at
171	the same time, each constructor has a variant with a trailing C<_ns> in	322	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
177		328
178	Also, all methods changing some aspect of a watcher (->set, ->priority,	329	Also, all methods changing some aspect of a watcher (->set, ->priority,
179	->fh and so on) automatically stop and start it again if it is active,	330	->fh and so on) automatically stop and start it again if it is active,
180	which means pending events get lost.	331	which means pending events get lost.
181		332
182	=head2 WATCHER TYPES	333	=head2 COMMON WATCHER METHODS
183		334
184	Now lets move to the existing watcher types and asociated methods.	335	This section lists methods common to all watchers.
185
186	The following methods are available for all watchers. Then followes a
187	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
188	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
189	any type-specific methods (if any).
190		336
191	=over 4	337	=over 4
192		338
193	=item $w->start	339	=item $w->start
194		340
…		…
198		344
199	=item $w->stop	345	=item $w->stop
200		346
201	Stop a watcher if it is active. Also clear any pending events (events that	347	Stop a watcher if it is active. Also clear any pending events (events that
202	have been received but that didn't yet result in a callback invocation),	348	have been received but that didn't yet result in a callback invocation),
203	regardless of wether the watcher was active or not.	349	regardless of whether the watcher was active or not.
204		350
205	=item $bool = $w->is_active	351	=item $bool = $w->is_active
206		352
207	Returns true if the watcher is active, false otherwise.	353	Returns true if the watcher is active, false otherwise.
208		354
…		…
233	watchers with higher priority will be invoked first. The valid range of	379	watchers with higher priority will be invoked first. The valid range of
234	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	380	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
235	-2). If the priority is outside this range it will automatically be	381	-2). If the priority is outside this range it will automatically be
236	normalised to the nearest valid priority.	382	normalised to the nearest valid priority.
237		383
238	The default priority of any newly-created weatcher is 0.	384	The default priority of any newly-created watcher is 0.
239		385
		386	Note that the priority semantics have not yet been fleshed out and are
		387	subject to almost certain change.
		388
240	=item $w->trigger ($revents)	389	=item $w->invoke ($revents)
241		390
242	Call the callback now with the given event mask.	391	Call the callback now with the given event mask.
243		392
		393	=item $w->feed_event ($revents)
		394
		395	Feed some events on this watcher into EV. EV will react to this call as if
		396	the watcher had received the given C<$revents> mask.
		397
		398	=item $revents = $w->clear_pending
		399
		400	If the watcher is pending, this function clears its pending status and
		401	returns its C<$revents> bitset (as if its callback was invoked). If the
		402	watcher isn't pending it does nothing and returns C<0>.
		403
		404	=item $previous_state = $w->keepalive ($bool)
		405
		406	Normally, C<EV::loop> will return when there are no active watchers
		407	(which is a "deadlock" because no progress can be made anymore). This is
		408	convinient because it allows you to start your watchers (and your jobs),
		409	call C<EV::loop> once and when it returns you know that all your jobs are
		410	finished (or they forgot to register some watchers for their task :).
		411
		412	Sometimes, however, this gets in your way, for example when the module
		413	that calls C<EV::loop> (usually the main program) is not the same module
		414	as a long-living watcher (for example a DNS client module written by
		415	somebody else even). Then you might want any outstanding requests to be
		416	handled, but you would not want to keep C<EV::loop> from returning just
		417	because you happen to have this long-running UDP port watcher.
		418
		419	In this case you can clear the keepalive status, which means that even
		420	though your watcher is active, it won't keep C<EV::loop> from returning.
		421
		422	The initial value for keepalive is true (enabled), and you can change it
		423	any time.
		424
		425	Example: Register an I/O watcher for some UDP socket but do not keep the
		426	event loop from running just because of that watcher.
		427
		428	my $udp_socket = ...
		429	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		430	$udp_watcher->keepalive (0);
		431
		432	=item $loop = $w->loop
		433
		434	Return the loop that this watcher is attached to.
		435
		436	=back
		437
		438
		439	=head1 WATCHER TYPES
		440
		441	Each of the following subsections describes a single watcher type.
		442
		443	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		444
		445	=over 4
244		446
245	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	447	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
246		448
247	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	449	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
248		450
		451	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		452
		453	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		454
249	As long as the returned watcher object is alive, call the C<$callback>	455	As long as the returned watcher object is alive, call the C<$callback>
250	when the events specified in C<$eventmask>.	456	when at least one of events specified in C<$eventmask> occurs.
251		457
252	The $eventmask can be one or more of these constants ORed together:	458	The $eventmask can be one or more of these constants ORed together:
253		459
254	EV::READ wait until read() wouldn't block anymore	460	EV::READ wait until read() wouldn't block anymore
255	EV::WRITE wait until write() wouldn't block anymore	461	EV::WRITE wait until write() wouldn't block anymore
…		…
271		477
272	=item $old_eventmask = $w->events ($new_eventmask)	478	=item $old_eventmask = $w->events ($new_eventmask)
273		479
274	Returns the previously set event mask and optionally set a new one.	480	Returns the previously set event mask and optionally set a new one.
275		481
		482	=back
		483
		484
		485	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		486
		487	=over 4
276		488
277	=item $w = EV::timer $after, $repeat, $callback	489	=item $w = EV::timer $after, $repeat, $callback
278		490
279	=item $w = EV::timer_ns $after, $repeat, $callback	491	=item $w = EV::timer_ns $after, $repeat, $callback
280		492
281	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	493	=item $w = $loop->timer ($after, $repeat, $callback)
282	the timer will be restarted (with the $repeat value as $after) after the	494
283	callback returns.	495	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		496
		497	Calls the callback after C<$after> seconds (which may be fractional). If
		498	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		499	value as $after) after the callback returns.
284		500
285	This means that the callback would be called roughly after C<$after>	501	This means that the callback would be called roughly after C<$after>
286	seconds, and then every C<$repeat> seconds. The timer does his best not	502	seconds, and then every C<$repeat> seconds. The timer does his best not
287	to drift, but it will not invoke the timer more often then once per event	503	to drift, but it will not invoke the timer more often then once per event
288	loop iteration, and might drift in other cases. If that isn't acceptable,	504	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
294		510
295	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	511	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
296		512
297	=item $w->set ($after, $repeat)	513	=item $w->set ($after, $repeat)
298		514
299	Reconfigures the watcher, see the constructor above for details. Can be at	515	Reconfigures the watcher, see the constructor above for details. Can be called at
300	any time.	516	any time.
301		517
302	=item $w->again	518	=item $w->again
303		519
304	Similar to the C<start> method, but has special semantics for repeating timers:	520	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
315	This behaviour is useful when you have a timeout for some IO	531	This behaviour is useful when you have a timeout for some IO
316	operation. You create a timer object with the same value for C<$after> and	532	operation. You create a timer object with the same value for C<$after> and
317	C<$repeat>, and then, in the read/write watcher, run the C<again> method	533	C<$repeat>, and then, in the read/write watcher, run the C<again> method
318	on the timeout.	534	on the timeout.
319		535
		536	=back
		537
		538
		539	=head3 PERIODIC WATCHERS - to cron or not to cron?
		540
		541	=over 4
320		542
321	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	543	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
322		544
323	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	545	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		546
		547	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		548
		549	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
324		550
325	Similar to EV::timer, but is not based on relative timeouts but on	551	Similar to EV::timer, but is not based on relative timeouts but on
326	absolute times. Apart from creating "simple" timers that trigger "at" the	552	absolute times. Apart from creating "simple" timers that trigger "at" the
327	specified time, it can also be used for non-drifting absolute timers and	553	specified time, it can also be used for non-drifting absolute timers and
328	more complex, cron-like, setups that are not adversely affected by time	554	more complex, cron-like, setups that are not adversely affected by time
…		…
338	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	564	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
339	will not adjust when a time jump occurs, that is, if it is to be run	565	will not adjust when a time jump occurs, that is, if it is to be run
340	at January 1st 2011 then it will run when the system time reaches or	566	at January 1st 2011 then it will run when the system time reaches or
341	surpasses this time.	567	surpasses this time.
342		568
343	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	569	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
344		570
345	In this mode the watcher will always be scheduled to time out at the	571	In this mode the watcher will always be scheduled to time out at the
346	next C<$at + N * $interval> time (for some integer N) and then repeat,	572	next C<$at + N * $interval> time (for some integer N) and then repeat,
347	regardless of any time jumps.	573	regardless of any time jumps.
348		574
…		…
366	time the periodic watcher gets scheduled, the reschedule callback	592	time the periodic watcher gets scheduled, the reschedule callback
367	($reschedule_cb) will be called with the watcher as first, and the current	593	($reschedule_cb) will be called with the watcher as first, and the current
368	time as second argument.	594	time as second argument.
369		595
370	I<This callback MUST NOT stop or destroy this or any other periodic	596	I<This callback MUST NOT stop or destroy this or any other periodic
371	watcher, ever>. If you need to stop it, return 1e30 and stop it	597	watcher, ever, and MUST NOT call any event loop functions or methods>. If
372	afterwards.	598	you need to stop it, return 1e30 and stop it afterwards. You may create
		599	and start a C<EV::prepare> watcher for this task.
373		600
374	It must return the next time to trigger, based on the passed time value	601	It must return the next time to trigger, based on the passed time value
375	(that is, the lowest time value larger than to the second argument). It	602	(that is, the lowest time value larger than or equal to to the second
376	will usually be called just before the callback will be triggered, but	603	argument). It will usually be called just before the callback will be
377	might be called at other times, too.	604	triggered, but might be called at other times, too.
378		605
379	This can be used to create very complex timers, such as a timer that	606	This can be used to create very complex timers, such as a timer that
380	triggers on each midnight, local time (actually 24 hours after the last	607	triggers on each midnight, local time (actually 24 hours after the last
381	midnight, to keep the example simple. If you know a way to do it correctly	608	midnight, to keep the example simple. If you know a way to do it correctly
382	in about the same space (without requiring elaborate modules), drop me a	609	in about the same space (without requiring elaborate modules), drop me a
…		…
396		623
397	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	624	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
398		625
399	=item $w->set ($at, $interval, $reschedule_cb)	626	=item $w->set ($at, $interval, $reschedule_cb)
400		627
401	Reconfigures the watcher, see the constructor above for details. Can be at	628	Reconfigures the watcher, see the constructor above for details. Can be called at
402	any time.	629	any time.
403		630
404	=item $w->again	631	=item $w->again
405		632
406	Simply stops and starts the watcher again.	633	Simply stops and starts the watcher again.
407		634
		635	=item $time = $w->at
		636
		637	Return the time that the watcher is expected to trigger next.
		638
		639	=back
		640
		641
		642	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		643
		644	=over 4
408		645
409	=item $w = EV::signal $signal, $callback	646	=item $w = EV::signal $signal, $callback
410		647
411	=item $w = EV::signal_ns $signal, $callback	648	=item $w = EV::signal_ns $signal, $callback
412		649
413	Call the callback when $signal is received (the signal can be specified	650	Call the callback when $signal is received (the signal can be specified by
414	by number or by name, just as with kill or %SIG).	651	number or by name, just as with C<kill> or C<%SIG>).
415		652
416	EV will grab the signal for the process (the kernel only allows one	653	EV will grab the signal for the process (the kernel only allows one
417	component to receive a signal at a time) when you start a signal watcher,	654	component to receive a signal at a time) when you start a signal watcher,
418	and removes it again when you stop it. Perl does the same when you	655	and removes it again when you stop it. Perl does the same when you
419	add/remove callbacks to %SIG, so watch out.	656	add/remove callbacks to C<%SIG>, so watch out.
420		657
421	You can have as many signal watchers per signal as you want.	658	You can have as many signal watchers per signal as you want.
422		659
423	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	660	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
424		661
425	=item $w->set ($signal)	662	=item $w->set ($signal)
426		663
427	Reconfigures the watcher, see the constructor above for details. Can be at	664	Reconfigures the watcher, see the constructor above for details. Can be
428	any time.	665	called at any time.
429		666
430	=item $current_signum = $w->signal	667	=item $current_signum = $w->signal
431		668
432	=item $old_signum = $w->signal ($new_signal)	669	=item $old_signum = $w->signal ($new_signal)
433		670
434	Returns the previously set signal (always as a number not name) and	671	Returns the previously set signal (always as a number not name) and
435	optionally set a new one.	672	optionally set a new one.
436		673
		674	=back
437		675
		676
		677	=head3 CHILD WATCHERS - watch out for process status changes
		678
		679	=over 4
		680
438	=item $w = EV::child $pid, $callback	681	=item $w = EV::child $pid, $trace, $callback
439		682
440	=item $w = EV::child_ns $pid, $callback	683	=item $w = EV::child_ns $pid, $trace, $callback
		684
		685	=item $w = $loop->child ($pid, $trace, $callback)
		686
		687	=item $w = $loop->child_ns ($pid, $trace, $callback)
441		688
442	Call the callback when a status change for pid C<$pid> (or any pid	689	Call the callback when a status change for pid C<$pid> (or any pid
443	if C<$pid> is 0) has been received. More precisely: when the process	690	if C<$pid> is 0) has been received (a status change happens when the
		691	process terminates or is killed, or, when trace is true, additionally when
		692	it is stopped or continued). More precisely: when the process receives
444	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	693	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
445	changed/zombie children and call the callback.	694	changed/zombie children and call the callback.
446		695
447	You can access both status and pid by using the C<rstatus> and C<rpid>	696	It is valid (and fully supported) to install a child watcher after a child
448	methods on the watcher object.	697	has exited but before the event loop has started its next iteration (for
		698	example, first you C<fork>, then the new child process might exit, and
		699	only then do you install a child watcher in the parent for the new pid).
449		700
		701	You can access both exit (or tracing) status and pid by using the
		702	C<rstatus> and C<rpid> methods on the watcher object.
		703
450	You can have as many pid watchers per pid as you want.	704	You can have as many pid watchers per pid as you want, they will all be
		705	called.
451		706
452	The C<child_ns> variant doesn't start (activate) the newly created watcher.	707	The C<child_ns> variant doesn't start (activate) the newly created watcher.
453		708
454	=item $w->set ($pid)	709	=item $w->set ($pid, $trace)
455		710
456	Reconfigures the watcher, see the constructor above for details. Can be at	711	Reconfigures the watcher, see the constructor above for details. Can be called at
457	any time.	712	any time.
458		713
459	=item $current_pid = $w->pid	714	=item $current_pid = $w->pid
460
461	=item $old_pid = $w->pid ($new_pid)
462		715
463	Returns the previously set process id and optionally set a new one.	716	Returns the previously set process id and optionally set a new one.
464		717
465	=item $exit_status = $w->rstatus	718	=item $exit_status = $w->rstatus
466		719
…		…
470	=item $pid = $w->rpid	723	=item $pid = $w->rpid
471		724
472	Return the pid of the awaited child (useful when you have installed a	725	Return the pid of the awaited child (useful when you have installed a
473	watcher for all pids).	726	watcher for all pids).
474		727
		728	=back
		729
		730
		731	=head3 STAT WATCHERS - did the file attributes just change?
		732
		733	=over 4
		734
		735	=item $w = EV::stat $path, $interval, $callback
		736
		737	=item $w = EV::stat_ns $path, $interval, $callback
		738
		739	=item $w = $loop->stat ($path, $interval, $callback)
		740
		741	=item $w = $loop->stat_ns ($path, $interval, $callback)
		742
		743	Call the callback when a file status change has been detected on
		744	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		745	to "path does not exist" is a status change like any other.
		746
		747	The C<$interval> is a recommended polling interval for systems where
		748	OS-supported change notifications don't exist or are not supported. If
		749	you use C<0> then an unspecified default is used (which is highly
		750	recommended!), which is to be expected to be around five seconds usually.
		751
		752	This watcher type is not meant for massive numbers of stat watchers,
		753	as even with OS-supported change notifications, this can be
		754	resource-intensive.
		755
		756	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		757
		758	=item ... = $w->stat
		759
		760	This call is very similar to the perl C<stat> built-in: It stats (using
		761	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		762	well as EV's idea of the current stat values) to the values found.
		763
		764	In scalar context, a boolean is return indicating success or failure of
		765	the stat. In list context, the same 13-value list as with stat is returned
		766	(except that the blksize and blocks fields are not reliable).
		767
		768	In the case of an error, errno is set to C<ENOENT> (regardless of the
		769	actual error value) and the C<nlink> value is forced to zero (if the stat
		770	was successful then nlink is guaranteed to be non-zero).
		771
		772	See also the next two entries for more info.
		773
		774	=item ... = $w->attr
		775
		776	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		777	the values most recently detected by EV. See the next entry for more info.
		778
		779	=item ... = $w->prev
		780
		781	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		782	the previous set of values, before the change.
		783
		784	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		785	to the values found I<before> a change was detected, while C<< $w->attr >>
		786	returns the values found leading to the change detection. The difference (if any)
		787	between C<prev> and C<attr> is what triggered the callback.
		788
		789	If you did something to the filesystem object and do not want to trigger
		790	yet another change, you can call C<stat> to update EV's idea of what the
		791	current attributes are.
		792
		793	=item $w->set ($path, $interval)
		794
		795	Reconfigures the watcher, see the constructor above for details. Can be
		796	called at any time.
		797
		798	=item $current_path = $w->path
		799
		800	=item $old_path = $w->path ($new_path)
		801
		802	Returns the previously set path and optionally set a new one.
		803
		804	=item $current_interval = $w->interval
		805
		806	=item $old_interval = $w->interval ($new_interval)
		807
		808	Returns the previously set interval and optionally set a new one. Can be
		809	used to query the actual interval used.
		810
		811	=back
		812
		813
		814	=head3 IDLE WATCHERS - when you've got nothing better to do...
		815
		816	=over 4
475		817
476	=item $w = EV::idle $callback	818	=item $w = EV::idle $callback
477		819
478	=item $w = EV::idle_ns $callback	820	=item $w = EV::idle_ns $callback
479		821
480	Call the callback when there are no pending io, timer/periodic, signal or	822	=item $w = $loop->idle ($callback)
481	child events, i.e. when the process is idle.	823
		824	=item $w = $loop->idle_ns ($callback)
		825
		826	Call the callback when there are no other pending watchers of the same or
		827	higher priority (excluding check, prepare and other idle watchers of the
		828	same or lower priority, of course). They are called idle watchers because
		829	when the watcher is the highest priority pending event in the process, the
		830	process is considered to be idle at that priority.
		831
		832	If you want a watcher that is only ever called when I<no> other events are
		833	outstanding you have to set the priority to C<EV::MINPRI>.
482		834
483	The process will not block as long as any idle watchers are active, and	835	The process will not block as long as any idle watchers are active, and
484	they will be called repeatedly until stopped.	836	they will be called repeatedly until stopped.
485		837
		838	For example, if you have idle watchers at priority C<0> and C<1>, and
		839	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		840	and the I/O watcher will always run when ready. Only when the idle watcher
		841	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		842	pending with the C<0>-priority idle watcher be invoked.
		843
486	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	844	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
487		845
		846	=back
		847
		848
		849	=head3 PREPARE WATCHERS - customise your event loop!
		850
		851	=over 4
488		852
489	=item $w = EV::prepare $callback	853	=item $w = EV::prepare $callback
490		854
491	=item $w = EV::prepare_ns $callback	855	=item $w = EV::prepare_ns $callback
		856
		857	=item $w = $loop->prepare ($callback)
		858
		859	=item $w = $loop->prepare_ns ($callback)
492		860
493	Call the callback just before the process would block. You can still	861	Call the callback just before the process would block. You can still
494	create/modify any watchers at this point.	862	create/modify any watchers at this point.
495		863
496	See the EV::check watcher, below, for explanations and an example.	864	See the EV::check watcher, below, for explanations and an example.
497		865
498	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	866	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
499		867
		868	=back
		869
		870
		871	=head3 CHECK WATCHERS - customise your event loop even more!
		872
		873	=over 4
500		874
501	=item $w = EV::check $callback	875	=item $w = EV::check $callback
502		876
503	=item $w = EV::check_ns $callback	877	=item $w = EV::check_ns $callback
		878
		879	=item $w = $loop->check ($callback)
		880
		881	=item $w = $loop->check_ns ($callback)
504		882
505	Call the callback just after the process wakes up again (after it has	883	Call the callback just after the process wakes up again (after it has
506	gathered events), but before any other callbacks have been invoked.	884	gathered events), but before any other callbacks have been invoked.
507		885
508	This is used to integrate other event-based software into the EV	886	This is used to integrate other event-based software into the EV
…		…
518	or return;	896	or return;
519		897
520	# make the dispatcher handle any outstanding stuff	898	# make the dispatcher handle any outstanding stuff
521	... not shown	899	... not shown
522		900
523	# create an IO watcher for each and every socket	901	# create an I/O watcher for each and every socket
524	@snmp_watcher = (	902	@snmp_watcher = (
525	(map { EV::io $_, EV::READ, sub { } }	903	(map { EV::io $_, EV::READ, sub { } }
526	keys %{ $dispatcher->{_descriptors} }),	904	keys %{ $dispatcher->{_descriptors} }),
527		905
528	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	906	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
543	# make the dispatcher handle any new stuff	921	# make the dispatcher handle any new stuff
544	... not shown	922	... not shown
545	};	923	};
546		924
547	The callbacks of the created watchers will not be called as the watchers	925	The callbacks of the created watchers will not be called as the watchers
548	are destroyed before this cna happen (remember EV::check gets called	926	are destroyed before this can happen (remember EV::check gets called
549	first).	927	first).
550		928
551	The C<check_ns> variant doesn't start (activate) the newly created watcher.	929	The C<check_ns> variant doesn't start (activate) the newly created watcher.
552		930
553	=back	931	=back
		932
		933
		934	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		935
		936	Fork watchers are called when a C<fork ()> was detected. The invocation
		937	is done before the event loop blocks next and before C<check> watchers
		938	are being called, and only in the child after the fork.
		939
		940	=over 4
		941
		942	=item $w = EV::fork $callback
		943
		944	=item $w = EV::fork_ns $callback
		945
		946	=item $w = $loop->fork ($callback)
		947
		948	=item $w = $loop->fork_ns ($callback)
		949
		950	Call the callback before the event loop is resumed in the child process
		951	after a fork.
		952
		953	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		954
		955	=back
		956
		957
		958	=head3 EMBED WATCHERS - when one backend isn't enough...
		959
		960	This is a rather advanced watcher type that lets you embed one event loop
		961	into another (currently only IO events are supported in the embedded
		962	loop, other types of watchers might be handled in a delayed or incorrect
		963	fashion and must not be used).
		964
		965	See the libev documentation at
		966	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		967	(locally installed as F<EV::libev>) for more details.
		968
		969	In short, this watcher is most useful on BSD systems without working
		970	kqueue to still be able to handle a large number of sockets:
		971
		972	my $socket_loop;
		973
		974	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		975	if (
		976	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		977	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		978	) {
		979	# use kqueue for sockets
		980	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		981	}
		982
		983	# use the default loop otherwise
		984	$socket_loop \|\|= EV::default_loop;
		985
		986	=over 4
		987
		988	=item $w = EV::embed $otherloop[, $callback]
		989
		990	=item $w = EV::embed_ns $otherloop[, $callback]
		991
		992	=item $w = $loop->embed ($otherloop[, $callback])
		993
		994	=item $w = $loop->embed_ns ($otherloop[, $callback])
		995
		996	Call the callback when the embedded event loop (C<$otherloop>) has any
		997	I/O activity. The C<$callback> is optional: if it is missing, then the
		998	embedded event loop will be managed automatically (which is recommended),
		999	otherwise you have to invoke C<sweep> yourself.
		1000
		1001	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1002
		1003	=back
		1004
		1005	=head3 ASYNC WATCHERS - how to wake up another event loop
		1006
		1007	Async watchers are provided by EV, but have little use in perl directly, as perl
		1008	neither supports threads nor direct access to signal handlers or other
		1009	contexts where they could be of value.
		1010
		1011	It is, however, possible to use them from the XS level.
		1012
		1013	Please see the libev documentation for further details.
		1014
		1015	=over 4
		1016
		1017	=item $w = EV::async $callback
		1018
		1019	=item $w = EV::async_ns $callback
		1020
		1021	=item $w->send
		1022
		1023	=item $bool = $w->async_pending
		1024
		1025	=back
		1026
		1027
		1028	=head1 PERL SIGNALS
		1029
		1030	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1031	with EV is as the same as any other C library: Perl-signals will only be
		1032	handled when Perl runs, which means your signal handler might be invoked
		1033	only the next time an event callback is invoked.
		1034
		1035	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1036	ensure proper operations with regards to other event watchers.
		1037
		1038	If you cannot do this for whatever reason, you can also force a watcher
		1039	to be called on every event loop iteration by installing a C<EV::check>
		1040	watcher:
		1041
		1042	my $async_check = EV::check sub { };
		1043
		1044	This ensures that perl gets into control for a short time to handle any
		1045	pending signals, and also ensures (slightly) slower overall operation.
554		1046
555	=head1 THREADS	1047	=head1 THREADS
556		1048
557	Threads are not supported by this module in any way. Perl pseudo-threads	1049	Threads are not supported by this module in any way. Perl pseudo-threads
558	is evil stuff and must die. As soon as Perl gains real threads I will work	1050	is evil stuff and must die. As soon as Perl gains real threads I will work
…		…
580	our $DIED = sub {	1072	our $DIED = sub {
581	warn "EV: error in callback (ignoring): $@";	1073	warn "EV: error in callback (ignoring): $@";
582	};	1074	};
583		1075
584	default_loop	1076	default_loop
585	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1077	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
586		1078
587	1;	1079	1;
588		1080
589	=head1 SEE ALSO	1081	=head1 SEE ALSO
590		1082
591	L<EV::DNS>.	1083	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1084	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1085	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1086	event-loop agnostic and portable event driven programming.
592		1087
593	=head1 AUTHOR	1088	=head1 AUTHOR
594		1089
595	Marc Lehmann <schmorp@schmorp.de>	1090	Marc Lehmann <schmorp@schmorp.de>
596	http://home.schmorp.de/	1091	http://home.schmorp.de/
597		1092
598	=cut	1093	=cut
599		1094

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Comparing EV/EV.pm (file contents): Revision 1.47 by root, Fri Nov 23 13:08:55 2007 UTC vs. Revision 1.108 by root, Mon Nov 3 12:13:15 2008 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.47 by root, Fri Nov 23 13:08:55 2007 UTC vs.
Revision 1.108 by root, Mon Nov 3 12:13:15 2008 UTC