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

Comparing EV/EV.pm (file contents):
Revision 1.48 by root, Fri Nov 23 13:09:02 2007 UTC vs.
Revision 1.105 by root, Thu Oct 2 12:27:55 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.
54		72
55	=cut	73	=cut
56		74
57	package EV;	75	package EV;
58		76
		77	no warnings;
59	use strict;	78	use strict;
60		79
61	BEGIN {	80	BEGIN {
62	our $VERSION = '1.2';	81	our $VERSION = '3.44';
63	use XSLoader;	82	use XSLoader;
64	XSLoader::load "EV", $VERSION;	83	XSLoader::load "EV", $VERSION;
65	}	84	}
66		85
67	@EV::Io::ISA =	86	@EV::IO::ISA =
68	@EV::Timer::ISA =	87	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	88	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	89	@EV::Signal::ISA =
		90	@EV::Child::ISA =
		91	@EV::Stat::ISA =
71	@EV::Idle::ISA =	92	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	93	@EV::Prepare::ISA =
73	@EV::Check::ISA =	94	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	95	@EV::Embed::ISA =
		96	@EV::Fork::ISA =
		97	@EV::Async::ISA =
		98	"EV::Watcher";
		99
		100	@EV::Loop::Default::ISA = "EV::Loop";
		101
		102	=head1 EVENT LOOPS
		103
		104	EV supports multiple event loops: There is a single "default event loop"
		105	that can handle everything including signals and child watchers, and any
		106	number of "dynamic event loops" that can use different backends (with
		107	various limitations), but no child and signal watchers.
		108
		109	You do not have to do anything to create the default event loop: When
		110	the module is loaded a suitable backend is selected on the premise of
		111	selecting a working backend (which for example rules out kqueue on most
		112	BSDs). Modules should, unless they have "special needs" always use the
		113	default loop as this is fastest (perl-wise), best supported by other
		114	modules (e.g. AnyEvent or Coro) and most portable event loop.
		115
		116	For specific programs you can create additional event loops dynamically.
		117
		118	If you want to take avdantage of kqueue (which often works properly for
		119	sockets only) even though the default loop doesn't enable it, you can
		120	I<embed> a kqueue loop into the default loop: running the default loop
		121	will then also service the kqueue loop to some extent. See the example in
		122	the section about embed watchers for an example on how to achieve that.
		123
		124	=over 4
		125
		126	=item $loop = new EV::loop [$flags]
		127
		128	Create a new event loop as per the specified flags. Please refer to
		129	the C<ev_loop_new ()> function description in the libev documentation
		130	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
		131	or locally-installed as F<EV::libev> manpage) for more info.
		132
		133	The loop will automatically be destroyed when it is no longer referenced
		134	by any watcher and the loop object goes out of scope.
		135
		136	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		137	is recommended, as only the default event loop is protected by this
		138	module. If you I<are> embedding this loop in the default loop, this is not
		139	necessary, as C<EV::embed> automatically does the right thing on fork.
		140
		141	=item $loop->loop_fork
		142
		143	Must be called after a fork in the child, before entering or continuing
		144	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		145	this function automatically, at some performance loss (refer to the libev
		146	documentation).
		147
		148	=item $loop->loop_verify
		149
		150	Calls C<ev_verify> to make internal consistency checks (for debugging
		151	libev) and abort the program if any data structures were found to be
		152	corrupted.
		153
		154	=item $loop = EV::default_loop [$flags]
		155
		156	Return the default loop (which is a singleton object). Since this module
		157	already creates the default loop with default flags, specifying flags here
		158	will not have any effect unless you destroy the default loop first, which
		159	isn't supported. So in short: don't do it, and if you break it, you get to
		160	keep the pieces.
		161
		162	=back
		163
75		164
76	=head1 BASIC INTERFACE	165	=head1 BASIC INTERFACE
77		166
78	=over 4	167	=over 4
79		168
80	=item $EV::DIED	169	=item $EV::DIED
81		170
82	Must contain a reference to a function that is called when a callback	171	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	172	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	173	informative message and continues.
85		174
86	If this callback throws an exception it will be silently ignored.	175	If this callback throws an exception it will be silently ignored.
87		176
		177	=item $flags = EV::supported_backends
		178
		179	=item $flags = EV::recommended_backends
		180
		181	=item $flags = EV::embeddable_backends
		182
		183	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		184	instance of EV, the set of recommended backends (supposed to be good) for
		185	this platform and the set of embeddable backends (see EMBED WATCHERS).
		186
		187	=item EV::sleep $seconds
		188
		189	Block the process for the given number of (fractional) seconds.
		190
88	=item $time = EV::time	191	=item $time = EV::time
89		192
90	Returns the current time in (fractional) seconds since the epoch.	193	Returns the current time in (fractional) seconds since the epoch.
91		194
92	=item $time = EV::now	195	=item $time = EV::now
		196
		197	=item $time = $loop->now
93		198
94	Returns the time the last event loop iteration has been started. This	199	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	200	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	201	usually faster then calling EV::time.
97		202
98	=item $method = EV::method	203	=item $backend = EV::backend
		204
		205	=item $backend = $loop->backend
99		206
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	207	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	208	or EV::METHOD_EPOLL).
102		209
103	=item EV::loop [$flags]	210	=item EV::loop [$flags]
		211
		212	=item $loop->loop ([$flags])
104		213
105	Begin checking for events and calling callbacks. It returns when a	214	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	215	callback calls EV::unloop.
107		216
108	The $flags argument can be one of the following:	217	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	220	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	221	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		222
114	=item EV::unloop [$how]	223	=item EV::unloop [$how]
115		224
		225	=item $loop->unloop ([$how])
		226
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	227	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	228	innermost call to EV::loop return.
118		229
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	230	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	231	fast as possible.
121		232
		233	=item $count = EV::loop_count
		234
		235	=item $count = $loop->loop_count
		236
		237	Return the number of times the event loop has polled for new
		238	events. Sometiems useful as a generation counter.
		239
122	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)	240	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		241
		242	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
123		243
124	This function rolls together an I/O and a timer watcher for a single	244	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.	245	one-shot event without the need for managing a watcher object.
126		246
127	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>	247	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	253	If timeout is C<undef> or negative, then there will be no
134	timeout. Otherwise a EV::timer with this value will be started.	254	timeout. Otherwise a EV::timer with this value will be started.
135		255
136	When an error occurs or either the timeout or I/O watcher triggers, then	256	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	257	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>,	258	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
139	C<EV::WRITE> and C<EV::TIMEOUT>).	259	C<EV::WRITE> and C<EV::TIMEOUT>).
140		260
141	EV::once doesn't return anything: the watchers stay active till either	261	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	262	of them triggers, then they will be stopped and freed, and the callback
143	invoked.	263	invoked.
144		264
145	=back	265	=item EV::feed_fd_event ($fd, $revents)
146		266
147	=head2 WATCHER	267	=item $loop->feed_fd_event ($fd, $revents)
		268
		269	Feed an event on a file descriptor into EV. EV will react to this call as
		270	if the readyness notifications specified by C<$revents> (a combination of
		271	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		272
		273	=item EV::feed_signal_event ($signal)
		274
		275	Feed a signal event into EV. EV will react to this call as if the signal
		276	specified by C<$signal> had occured.
		277
		278	=item EV::set_io_collect_interval $time
		279
		280	=item $loop->set_io_collect_interval ($time)
		281
		282	=item EV::set_timeout_collect_interval $time
		283
		284	=item $loop->set_timeout_collect_interval ($time)
		285
		286	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		287	wait interval for timer events. See the libev documentation at
		288	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		289	(locally installed as F<EV::libev>) for a more detailed discussion.
		290
		291	=back
		292
		293
		294	=head1 WATCHER OBJECTS
148		295
149	A watcher is an object that gets created to record your interest in some	296	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	297	event. For instance, if you want to wait for STDIN to become readable, you
151	would create an EV::io watcher for that:	298	would create an EV::io watcher for that:
152		299
153	my $watcher = EV::io *STDIN, EV::READ, sub {	300	my $watcher = EV::io *STDIN, EV::READ, sub {
154	my ($watcher, $revents) = @_;	301	my ($watcher, $revents) = @_;
155	warn "yeah, STDIN should not be readable without blocking!\n"	302	warn "yeah, STDIN should now be readable without blocking!\n"
156	};	303	};
157		304
158	All watchers can be active (waiting for events) or inactive (paused). Only	305	All watchers can be active (waiting for events) or inactive (paused). Only
159	active watchers will have their callbacks invoked. All callbacks will be	306	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	307	called with at least two arguments: the watcher and a bitmask of received
161	events.	308	events.
162		309
163	Each watcher type has its associated bit in revents, so you can use the	310	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	311	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,	312	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	313	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	314	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
168	uses EV::TIMEOUT).	315	uses EV::TIMEOUT).
169		316
170	In the rare case where one wants to create a watcher but not start it at	317	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	318	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
177		324
178	Also, all methods changing some aspect of a watcher (->set, ->priority,	325	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,	326	->fh and so on) automatically stop and start it again if it is active,
180	which means pending events get lost.	327	which means pending events get lost.
181		328
182	=head2 WATCHER TYPES	329	=head2 COMMON WATCHER METHODS
183		330
184	Now lets move to the existing watcher types and asociated methods.	331	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		332
191	=over 4	333	=over 4
192		334
193	=item $w->start	335	=item $w->start
194		336
…		…
198		340
199	=item $w->stop	341	=item $w->stop
200		342
201	Stop a watcher if it is active. Also clear any pending events (events that	343	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),	344	have been received but that didn't yet result in a callback invocation),
203	regardless of wether the watcher was active or not.	345	regardless of whether the watcher was active or not.
204		346
205	=item $bool = $w->is_active	347	=item $bool = $w->is_active
206		348
207	Returns true if the watcher is active, false otherwise.	349	Returns true if the watcher is active, false otherwise.
208		350
…		…
233	watchers with higher priority will be invoked first. The valid range of	375	watchers with higher priority will be invoked first. The valid range of
234	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	376	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
235	-2). If the priority is outside this range it will automatically be	377	-2). If the priority is outside this range it will automatically be
236	normalised to the nearest valid priority.	378	normalised to the nearest valid priority.
237		379
238	The default priority of any newly-created weatcher is 0.	380	The default priority of any newly-created watcher is 0.
239		381
		382	Note that the priority semantics have not yet been fleshed out and are
		383	subject to almost certain change.
		384
240	=item $w->trigger ($revents)	385	=item $w->invoke ($revents)
241		386
242	Call the callback now with the given event mask.	387	Call the callback now with the given event mask.
243		388
		389	=item $w->feed_event ($revents)
		390
		391	Feed some events on this watcher into EV. EV will react to this call as if
		392	the watcher had received the given C<$revents> mask.
		393
		394	=item $revents = $w->clear_pending
		395
		396	If the watcher is pending, this function clears its pending status and
		397	returns its C<$revents> bitset (as if its callback was invoked). If the
		398	watcher isn't pending it does nothing and returns C<0>.
		399
		400	=item $previous_state = $w->keepalive ($bool)
		401
		402	Normally, C<EV::loop> will return when there are no active watchers
		403	(which is a "deadlock" because no progress can be made anymore). This is
		404	convinient because it allows you to start your watchers (and your jobs),
		405	call C<EV::loop> once and when it returns you know that all your jobs are
		406	finished (or they forgot to register some watchers for their task :).
		407
		408	Sometimes, however, this gets in your way, for example when the module
		409	that calls C<EV::loop> (usually the main program) is not the same module
		410	as a long-living watcher (for example a DNS client module written by
		411	somebody else even). Then you might want any outstanding requests to be
		412	handled, but you would not want to keep C<EV::loop> from returning just
		413	because you happen to have this long-running UDP port watcher.
		414
		415	In this case you can clear the keepalive status, which means that even
		416	though your watcher is active, it won't keep C<EV::loop> from returning.
		417
		418	The initial value for keepalive is true (enabled), and you cna change it
		419	any time.
		420
		421	Example: Register an I/O watcher for some UDP socket but do not keep the
		422	event loop from running just because of that watcher.
		423
		424	my $udp_socket = ...
		425	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		426	$udp_watcher->keepalive (0);
		427
		428	=item $loop = $w->loop
		429
		430	Return the loop that this watcher is attached to.
		431
		432	=back
		433
		434
		435	=head1 WATCHER TYPES
		436
		437	Each of the following subsections describes a single watcher type.
		438
		439	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		440
		441	=over 4
244		442
245	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	443	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
246		444
247	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	445	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
248		446
		447	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		448
		449	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		450
249	As long as the returned watcher object is alive, call the C<$callback>	451	As long as the returned watcher object is alive, call the C<$callback>
250	when the events specified in C<$eventmask>.	452	when at least one of events specified in C<$eventmask> occurs.
251		453
252	The $eventmask can be one or more of these constants ORed together:	454	The $eventmask can be one or more of these constants ORed together:
253		455
254	EV::READ wait until read() wouldn't block anymore	456	EV::READ wait until read() wouldn't block anymore
255	EV::WRITE wait until write() wouldn't block anymore	457	EV::WRITE wait until write() wouldn't block anymore
…		…
271		473
272	=item $old_eventmask = $w->events ($new_eventmask)	474	=item $old_eventmask = $w->events ($new_eventmask)
273		475
274	Returns the previously set event mask and optionally set a new one.	476	Returns the previously set event mask and optionally set a new one.
275		477
		478	=back
		479
		480
		481	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		482
		483	=over 4
276		484
277	=item $w = EV::timer $after, $repeat, $callback	485	=item $w = EV::timer $after, $repeat, $callback
278		486
279	=item $w = EV::timer_ns $after, $repeat, $callback	487	=item $w = EV::timer_ns $after, $repeat, $callback
280		488
281	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	489	=item $w = $loop->timer ($after, $repeat, $callback)
282	the timer will be restarted (with the $repeat value as $after) after the	490
283	callback returns.	491	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		492
		493	Calls the callback after C<$after> seconds (which may be fractional). If
		494	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		495	value as $after) after the callback returns.
284		496
285	This means that the callback would be called roughly after C<$after>	497	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	498	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	499	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,	500	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
294		506
295	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	507	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
296		508
297	=item $w->set ($after, $repeat)	509	=item $w->set ($after, $repeat)
298		510
299	Reconfigures the watcher, see the constructor above for details. Can be at	511	Reconfigures the watcher, see the constructor above for details. Can be called at
300	any time.	512	any time.
301		513
302	=item $w->again	514	=item $w->again
303		515
304	Similar to the C<start> method, but has special semantics for repeating timers:	516	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
315	This behaviour is useful when you have a timeout for some IO	527	This behaviour is useful when you have a timeout for some IO
316	operation. You create a timer object with the same value for C<$after> and	528	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	529	C<$repeat>, and then, in the read/write watcher, run the C<again> method
318	on the timeout.	530	on the timeout.
319		531
		532	=back
		533
		534
		535	=head3 PERIODIC WATCHERS - to cron or not to cron?
		536
		537	=over 4
320		538
321	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	539	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
322		540
323	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	541	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		542
		543	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		544
		545	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
324		546
325	Similar to EV::timer, but is not based on relative timeouts but on	547	Similar to EV::timer, but is not based on relative timeouts but on
326	absolute times. Apart from creating "simple" timers that trigger "at" the	548	absolute times. Apart from creating "simple" timers that trigger "at" the
327	specified time, it can also be used for non-drifting absolute timers and	549	specified time, it can also be used for non-drifting absolute timers and
328	more complex, cron-like, setups that are not adversely affected by time	550	more complex, cron-like, setups that are not adversely affected by time
…		…
338	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	560	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
339	will not adjust when a time jump occurs, that is, if it is to be run	561	will not adjust when a time jump occurs, that is, if it is to be run
340	at January 1st 2011 then it will run when the system time reaches or	562	at January 1st 2011 then it will run when the system time reaches or
341	surpasses this time.	563	surpasses this time.
342		564
343	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	565	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
344		566
345	In this mode the watcher will always be scheduled to time out at the	567	In this mode the watcher will always be scheduled to time out at the
346	next C<$at + N * $interval> time (for some integer N) and then repeat,	568	next C<$at + N * $interval> time (for some integer N) and then repeat,
347	regardless of any time jumps.	569	regardless of any time jumps.
348		570
…		…
366	time the periodic watcher gets scheduled, the reschedule callback	588	time the periodic watcher gets scheduled, the reschedule callback
367	($reschedule_cb) will be called with the watcher as first, and the current	589	($reschedule_cb) will be called with the watcher as first, and the current
368	time as second argument.	590	time as second argument.
369		591
370	I<This callback MUST NOT stop or destroy this or any other periodic	592	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	593	watcher, ever, and MUST NOT call any event loop functions or methods>. If
372	afterwards.	594	you need to stop it, return 1e30 and stop it afterwards. You may create
		595	and start a C<EV::prepare> watcher for this task.
373		596
374	It must return the next time to trigger, based on the passed time value	597	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	598	(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	599	argument). It will usually be called just before the callback will be
377	might be called at other times, too.	600	triggered, but might be called at other times, too.
378		601
379	This can be used to create very complex timers, such as a timer that	602	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	603	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	604	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	605	in about the same space (without requiring elaborate modules), drop me a
…		…
396		619
397	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	620	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
398		621
399	=item $w->set ($at, $interval, $reschedule_cb)	622	=item $w->set ($at, $interval, $reschedule_cb)
400		623
401	Reconfigures the watcher, see the constructor above for details. Can be at	624	Reconfigures the watcher, see the constructor above for details. Can be called at
402	any time.	625	any time.
403		626
404	=item $w->again	627	=item $w->again
405		628
406	Simply stops and starts the watcher again.	629	Simply stops and starts the watcher again.
407		630
		631	=item $time = $w->at
		632
		633	Return the time that the watcher is expected to trigger next.
		634
		635	=back
		636
		637
		638	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		639
		640	=over 4
408		641
409	=item $w = EV::signal $signal, $callback	642	=item $w = EV::signal $signal, $callback
410		643
411	=item $w = EV::signal_ns $signal, $callback	644	=item $w = EV::signal_ns $signal, $callback
412		645
413	Call the callback when $signal is received (the signal can be specified	646	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).	647	number or by name, just as with C<kill> or C<%SIG>).
415		648
416	EV will grab the signal for the process (the kernel only allows one	649	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,	650	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	651	and removes it again when you stop it. Perl does the same when you
419	add/remove callbacks to %SIG, so watch out.	652	add/remove callbacks to C<%SIG>, so watch out.
420		653
421	You can have as many signal watchers per signal as you want.	654	You can have as many signal watchers per signal as you want.
422		655
423	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	656	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
424		657
425	=item $w->set ($signal)	658	=item $w->set ($signal)
426		659
427	Reconfigures the watcher, see the constructor above for details. Can be at	660	Reconfigures the watcher, see the constructor above for details. Can be
428	any time.	661	called at any time.
429		662
430	=item $current_signum = $w->signal	663	=item $current_signum = $w->signal
431		664
432	=item $old_signum = $w->signal ($new_signal)	665	=item $old_signum = $w->signal ($new_signal)
433		666
434	Returns the previously set signal (always as a number not name) and	667	Returns the previously set signal (always as a number not name) and
435	optionally set a new one.	668	optionally set a new one.
436		669
		670	=back
437		671
		672
		673	=head3 CHILD WATCHERS - watch out for process status changes
		674
		675	=over 4
		676
438	=item $w = EV::child $pid, $callback	677	=item $w = EV::child $pid, $trace, $callback
439		678
440	=item $w = EV::child_ns $pid, $callback	679	=item $w = EV::child_ns $pid, $trace, $callback
		680
		681	=item $w = $loop->child ($pid, $trace, $callback)
		682
		683	=item $w = $loop->child_ns ($pid, $trace, $callback)
441		684
442	Call the callback when a status change for pid C<$pid> (or any pid	685	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	686	if C<$pid> is 0) has been received (a status change happens when the
		687	process terminates or is killed, or, when trace is true, additionally when
		688	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	689	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
445	changed/zombie children and call the callback.	690	changed/zombie children and call the callback.
446		691
447	You can access both status and pid by using the C<rstatus> and C<rpid>	692	It is valid (and fully supported) to install a child watcher after a child
448	methods on the watcher object.	693	has exited but before the event loop has started its next iteration (for
		694	example, first you C<fork>, then the new child process might exit, and
		695	only then do you install a child watcher in the parent for the new pid).
449		696
		697	You can access both exit (or tracing) status and pid by using the
		698	C<rstatus> and C<rpid> methods on the watcher object.
		699
450	You can have as many pid watchers per pid as you want.	700	You can have as many pid watchers per pid as you want, they will all be
		701	called.
451		702
452	The C<child_ns> variant doesn't start (activate) the newly created watcher.	703	The C<child_ns> variant doesn't start (activate) the newly created watcher.
453		704
454	=item $w->set ($pid)	705	=item $w->set ($pid, $trace)
455		706
456	Reconfigures the watcher, see the constructor above for details. Can be at	707	Reconfigures the watcher, see the constructor above for details. Can be called at
457	any time.	708	any time.
458		709
459	=item $current_pid = $w->pid	710	=item $current_pid = $w->pid
460
461	=item $old_pid = $w->pid ($new_pid)
462		711
463	Returns the previously set process id and optionally set a new one.	712	Returns the previously set process id and optionally set a new one.
464		713
465	=item $exit_status = $w->rstatus	714	=item $exit_status = $w->rstatus
466		715
…		…
470	=item $pid = $w->rpid	719	=item $pid = $w->rpid
471		720
472	Return the pid of the awaited child (useful when you have installed a	721	Return the pid of the awaited child (useful when you have installed a
473	watcher for all pids).	722	watcher for all pids).
474		723
		724	=back
		725
		726
		727	=head3 STAT WATCHERS - did the file attributes just change?
		728
		729	=over 4
		730
		731	=item $w = EV::stat $path, $interval, $callback
		732
		733	=item $w = EV::stat_ns $path, $interval, $callback
		734
		735	=item $w = $loop->stat ($path, $interval, $callback)
		736
		737	=item $w = $loop->stat_ns ($path, $interval, $callback)
		738
		739	Call the callback when a file status change has been detected on
		740	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		741	to "path does not exist" is a status change like any other.
		742
		743	The C<$interval> is a recommended polling interval for systems where
		744	OS-supported change notifications don't exist or are not supported. If
		745	you use C<0> then an unspecified default is used (which is highly
		746	recommended!), which is to be expected to be around five seconds usually.
		747
		748	This watcher type is not meant for massive numbers of stat watchers,
		749	as even with OS-supported change notifications, this can be
		750	resource-intensive.
		751
		752	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		753
		754	=item ... = $w->stat
		755
		756	This call is very similar to the perl C<stat> built-in: It stats (using
		757	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		758	well as EV's idea of the current stat values) to the values found.
		759
		760	In scalar context, a boolean is return indicating success or failure of
		761	the stat. In list context, the same 13-value list as with stat is returned
		762	(except that the blksize and blocks fields are not reliable).
		763
		764	In the case of an error, errno is set to C<ENOENT> (regardless of the
		765	actual error value) and the C<nlink> value is forced to zero (if the stat
		766	was successful then nlink is guaranteed to be non-zero).
		767
		768	See also the next two entries for more info.
		769
		770	=item ... = $w->attr
		771
		772	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		773	the values most recently detected by EV. See the next entry for more info.
		774
		775	=item ... = $w->prev
		776
		777	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		778	the previous set of values, before the change.
		779
		780	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		781	to the values found I<before> a change was detected, while C<< $w->attr >>
		782	returns the values found leading to the change detection. The difference (if any)
		783	between C<prev> and C<attr> is what triggered the callback.
		784
		785	If you did something to the filesystem object and do not want to trigger
		786	yet another change, you can call C<stat> to update EV's idea of what the
		787	current attributes are.
		788
		789	=item $w->set ($path, $interval)
		790
		791	Reconfigures the watcher, see the constructor above for details. Can be
		792	called at any time.
		793
		794	=item $current_path = $w->path
		795
		796	=item $old_path = $w->path ($new_path)
		797
		798	Returns the previously set path and optionally set a new one.
		799
		800	=item $current_interval = $w->interval
		801
		802	=item $old_interval = $w->interval ($new_interval)
		803
		804	Returns the previously set interval and optionally set a new one. Can be
		805	used to query the actual interval used.
		806
		807	=back
		808
		809
		810	=head3 IDLE WATCHERS - when you've got nothing better to do...
		811
		812	=over 4
475		813
476	=item $w = EV::idle $callback	814	=item $w = EV::idle $callback
477		815
478	=item $w = EV::idle_ns $callback	816	=item $w = EV::idle_ns $callback
479		817
480	Call the callback when there are no pending io, timer/periodic, signal or	818	=item $w = $loop->idle ($callback)
481	child events, i.e. when the process is idle.	819
		820	=item $w = $loop->idle_ns ($callback)
		821
		822	Call the callback when there are no other pending watchers of the same or
		823	higher priority (excluding check, prepare and other idle watchers of the
		824	same or lower priority, of course). They are called idle watchers because
		825	when the watcher is the highest priority pending event in the process, the
		826	process is considered to be idle at that priority.
		827
		828	If you want a watcher that is only ever called when I<no> other events are
		829	outstanding you have to set the priority to C<EV::MINPRI>.
482		830
483	The process will not block as long as any idle watchers are active, and	831	The process will not block as long as any idle watchers are active, and
484	they will be called repeatedly until stopped.	832	they will be called repeatedly until stopped.
485		833
		834	For example, if you have idle watchers at priority C<0> and C<1>, and
		835	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		836	and the I/O watcher will always run when ready. Only when the idle watcher
		837	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		838	pending with the C<0>-priority idle watcher be invoked.
		839
486	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	840	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
487		841
		842	=back
		843
		844
		845	=head3 PREPARE WATCHERS - customise your event loop!
		846
		847	=over 4
488		848
489	=item $w = EV::prepare $callback	849	=item $w = EV::prepare $callback
490		850
491	=item $w = EV::prepare_ns $callback	851	=item $w = EV::prepare_ns $callback
		852
		853	=item $w = $loop->prepare ($callback)
		854
		855	=item $w = $loop->prepare_ns ($callback)
492		856
493	Call the callback just before the process would block. You can still	857	Call the callback just before the process would block. You can still
494	create/modify any watchers at this point.	858	create/modify any watchers at this point.
495		859
496	See the EV::check watcher, below, for explanations and an example.	860	See the EV::check watcher, below, for explanations and an example.
497		861
498	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	862	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
499		863
		864	=back
		865
		866
		867	=head3 CHECK WATCHERS - customise your event loop even more!
		868
		869	=over 4
500		870
501	=item $w = EV::check $callback	871	=item $w = EV::check $callback
502		872
503	=item $w = EV::check_ns $callback	873	=item $w = EV::check_ns $callback
		874
		875	=item $w = $loop->check ($callback)
		876
		877	=item $w = $loop->check_ns ($callback)
504		878
505	Call the callback just after the process wakes up again (after it has	879	Call the callback just after the process wakes up again (after it has
506	gathered events), but before any other callbacks have been invoked.	880	gathered events), but before any other callbacks have been invoked.
507		881
508	This is used to integrate other event-based software into the EV	882	This is used to integrate other event-based software into the EV
…		…
518	or return;	892	or return;
519		893
520	# make the dispatcher handle any outstanding stuff	894	# make the dispatcher handle any outstanding stuff
521	... not shown	895	... not shown
522		896
523	# create an IO watcher for each and every socket	897	# create an I/O watcher for each and every socket
524	@snmp_watcher = (	898	@snmp_watcher = (
525	(map { EV::io $_, EV::READ, sub { } }	899	(map { EV::io $_, EV::READ, sub { } }
526	keys %{ $dispatcher->{_descriptors} }),	900	keys %{ $dispatcher->{_descriptors} }),
527		901
528	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	902	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
549	first).	923	first).
550		924
551	The C<check_ns> variant doesn't start (activate) the newly created watcher.	925	The C<check_ns> variant doesn't start (activate) the newly created watcher.
552		926
553	=back	927	=back
		928
		929
		930	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		931
		932	Fork watchers are called when a C<fork ()> was detected. The invocation
		933	is done before the event loop blocks next and before C<check> watchers
		934	are being called, and only in the child after the fork.
		935
		936	=over 4
		937
		938	=item $w = EV::fork $callback
		939
		940	=item $w = EV::fork_ns $callback
		941
		942	=item $w = $loop->fork ($callback)
		943
		944	=item $w = $loop->fork_ns ($callback)
		945
		946	Call the callback before the event loop is resumed in the child process
		947	after a fork.
		948
		949	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		950
		951	=back
		952
		953
		954	=head3 EMBED WATCHERS - when one backend isn't enough...
		955
		956	This is a rather advanced watcher type that lets you embed one event loop
		957	into another (currently only IO events are supported in the embedded
		958	loop, other types of watchers might be handled in a delayed or incorrect
		959	fashion and must not be used).
		960
		961	See the libev documentation at
		962	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		963	(locally installed as F<EV::libev>) for more details.
		964
		965	In short, this watcher is most useful on BSD systems without working
		966	kqueue to still be able to handle a large number of sockets:
		967
		968	my $socket_loop;
		969
		970	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		971	if (
		972	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		973	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		974	) {
		975	# use kqueue for sockets
		976	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		977	}
		978
		979	# use the default loop otherwise
		980	$socket_loop \|\|= EV::default_loop;
		981
		982	=over 4
		983
		984	=item $w = EV::embed $otherloop[, $callback]
		985
		986	=item $w = EV::embed_ns $otherloop[, $callback]
		987
		988	=item $w = $loop->embed ($otherloop[, $callback])
		989
		990	=item $w = $loop->embed_ns ($otherloop[, $callback])
		991
		992	Call the callback when the embedded event loop (C<$otherloop>) has any
		993	I/O activity. The C<$callback> is optional: if it is missing, then the
		994	embedded event loop will be managed automatically (which is recommended),
		995	otherwise you have to invoke C<sweep> yourself.
		996
		997	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		998
		999	=back
		1000
		1001	=head3 ASYNC WATCHERS - how to wake up another event loop
		1002
		1003	Async watchers are provided by EV, but have little use in perl directly, as perl
		1004	neither supports threads nor direct access to signal handlers or other
		1005	contexts where they could be of value.
		1006
		1007	It is, however, possible to use them from the XS level.
		1008
		1009	Please see the libev documentation for further details.
		1010
		1011	=over 4
		1012
		1013	=item $w = EV::async $callback
		1014
		1015	=item $w = EV::async_ns $callback
		1016
		1017	=item $w->send
		1018
		1019	=item $bool = $w->async_pending
		1020
		1021	=back
		1022
		1023
		1024	=head1 PERL SIGNALS
		1025
		1026	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1027	with EV is as the same as any other C library: Perl-signals will only be
		1028	handled when Perl runs, which means your signal handler might be invoked
		1029	only the next time an event callback is invoked.
		1030
		1031	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1032	ensure proper operations with regards to other event watchers.
		1033
		1034	If you cannot do this for whatever reason, you can also force a watcher
		1035	to be called on every event loop iteration by installing a C<EV::check>
		1036	watcher:
		1037
		1038	my $async_check = EV::check sub { };
		1039
		1040	This ensures that perl gets into control for a short time to handle any
		1041	pending signals, and also ensures (slightly) slower overall operation.
554		1042
555	=head1 THREADS	1043	=head1 THREADS
556		1044
557	Threads are not supported by this module in any way. Perl pseudo-threads	1045	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	1046	is evil stuff and must die. As soon as Perl gains real threads I will work
…		…
580	our $DIED = sub {	1068	our $DIED = sub {
581	warn "EV: error in callback (ignoring): $@";	1069	warn "EV: error in callback (ignoring): $@";
582	};	1070	};
583		1071
584	default_loop	1072	default_loop
585	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1073	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
586		1074
587	1;	1075	1;
588		1076
589	=head1 SEE ALSO	1077	=head1 SEE ALSO
590		1078
591	L<EV::DNS>.	1079	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1080	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1081	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1082	event-loop agnostic and portable event driven programming.
592		1083
593	=head1 AUTHOR	1084	=head1 AUTHOR
594		1085
595	Marc Lehmann <schmorp@schmorp.de>	1086	Marc Lehmann <schmorp@schmorp.de>
596	http://home.schmorp.de/	1087	http://home.schmorp.de/
597		1088
598	=cut	1089	=cut
599		1090

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Comparing EV/EV.pm (file contents): Revision 1.48 by root, Fri Nov 23 13:09:02 2007 UTC vs. Revision 1.105 by root, Thu Oct 2 12:27:55 2008 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.48 by root, Fri Nov 23 13:09:02 2007 UTC vs.
Revision 1.105 by root, Thu Oct 2 12:27:55 2008 UTC