[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 1.101 by root, Sat Jul 12 22:19:22 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 libev
		61	itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more
		62	subtle details on watcher semantics or some discussion on the available
		63	backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just
		64	about in any case because it has much more detailed information.
		65
		66	This module is very fast and scalable. It is actually so fast that you
		67	can use it through the L<AnyEvent> module, stay portable to other event
		68	loops (if you don't rely on any watcher types not available through it)
		69	and still be faster than with any other event loop currently supported in
		70	Perl.
54		71
55	=cut	72	=cut
56		73
57	package EV;	74	package EV;
58		75
		76	no warnings;
59	use strict;	77	use strict;
60		78
61	BEGIN {	79	BEGIN {
62	our $VERSION = '1.2';	80	our $VERSION = '3.431';
63	use XSLoader;	81	use XSLoader;
64	XSLoader::load "EV", $VERSION;	82	XSLoader::load "EV", $VERSION;
65	}	83	}
66		84
67	@EV::Io::ISA =	85	@EV::IO::ISA =
68	@EV::Timer::ISA =	86	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	87	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	88	@EV::Signal::ISA =
		89	@EV::Child::ISA =
		90	@EV::Stat::ISA =
71	@EV::Idle::ISA =	91	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	92	@EV::Prepare::ISA =
73	@EV::Check::ISA =	93	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	94	@EV::Embed::ISA =
		95	@EV::Fork::ISA =
		96	@EV::Async::ISA =
		97	"EV::Watcher";
		98
		99	@EV::Loop::Default::ISA = "EV::Loop";
		100
		101	=head1 EVENT LOOPS
		102
		103	EV supports multiple event loops: There is a single "default event loop"
		104	that can handle everything including signals and child watchers, and any
		105	number of "dynamic event loops" that can use different backends (with
		106	various limitations), but no child and signal watchers.
		107
		108	You do not have to do anything to create the default event loop: When
		109	the module is loaded a suitable backend is selected on the premise of
		110	selecting a working backend (which for example rules out kqueue on most
		111	BSDs). Modules should, unless they have "special needs" always use the
		112	default loop as this is fastest (perl-wise), best supported by other
		113	modules (e.g. AnyEvent or Coro) and most portable event loop.
		114
		115	For specific programs you can create additional event loops dynamically.
		116
		117	If you want to take avdantage of kqueue (which often works properly for
		118	sockets only) even though the default loop doesn't enable it, you can
		119	I<embed> a kqueue loop into the default loop: running the default loop
		120	will then also service the kqueue loop to some extent. See the example in
		121	the section about embed watchers for an example on how to achieve that.
		122
		123	=over 4
		124
		125	=item $loop = new EV::loop [$flags]
		126
		127	Create a new event loop as per the specified flags. Please refer to the
		128	C<ev_loop_new ()> function description in the libev documentation
		129	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		130	for more info.
		131
		132	The loop will automatically be destroyed when it is no longer referenced
		133	by any watcher and the loop object goes out of scope.
		134
		135	Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
		136	is protected by this module.
		137
		138	=item $loop->loop_fork
		139
		140	Must be called after a fork in the child, before entering or continuing
		141	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		142	this function automatically, at some performance loss (refer to the libev
		143	documentation).
		144
		145	=item $loop->loop_verify
		146
		147	Calls C<ev_verify> to make internal consistency checks (for debugging
		148	libev) and abort the program if any data structures were found to be
		149	corrupted.
		150
		151	=item $loop = EV::default_loop [$flags]
		152
		153	Return the default loop (which is a singleton object). Since this module
		154	already creates the default loop with default flags, specifying flags here
		155	will not have any effect unless you destroy the default loop first, which
		156	isn't supported. So in short: don't do it, and if you break it, you get to
		157	keep the pieces.
		158
		159	=back
		160
75		161
76	=head1 BASIC INTERFACE	162	=head1 BASIC INTERFACE
77		163
78	=over 4	164	=over 4
79		165
80	=item $EV::DIED	166	=item $EV::DIED
81		167
82	Must contain a reference to a function that is called when a callback	168	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	169	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	170	informative message and continues.
85		171
86	If this callback throws an exception it will be silently ignored.	172	If this callback throws an exception it will be silently ignored.
87		173
		174	=item $flags = EV::supported_backends
		175
		176	=item $flags = EV::recommended_backends
		177
		178	=item $flags = EV::embeddable_backends
		179
		180	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		181	instance of EV, the set of recommended backends (supposed to be good) for
		182	this platform and the set of embeddable backends (see EMBED WATCHERS).
		183
		184	=item EV::sleep $seconds
		185
		186	Block the process for the given number of (fractional) seconds.
		187
88	=item $time = EV::time	188	=item $time = EV::time
89		189
90	Returns the current time in (fractional) seconds since the epoch.	190	Returns the current time in (fractional) seconds since the epoch.
91		191
92	=item $time = EV::now	192	=item $time = EV::now
		193
		194	=item $time = $loop->now
93		195
94	Returns the time the last event loop iteration has been started. This	196	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	197	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	198	usually faster then calling EV::time.
97		199
98	=item $method = EV::method	200	=item $backend = EV::backend
		201
		202	=item $backend = $loop->backend
99		203
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	204	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	205	or EV::METHOD_EPOLL).
102		206
103	=item EV::loop [$flags]	207	=item EV::loop [$flags]
		208
		209	=item $loop->loop ([$flags])
104		210
105	Begin checking for events and calling callbacks. It returns when a	211	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	212	callback calls EV::unloop.
107		213
108	The $flags argument can be one of the following:	214	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	217	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	218	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		219
114	=item EV::unloop [$how]	220	=item EV::unloop [$how]
115		221
		222	=item $loop->unloop ([$how])
		223
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	224	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	225	innermost call to EV::loop return.
118		226
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	227	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	228	fast as possible.
121		229
		230	=item $count = EV::loop_count
		231
		232	=item $count = $loop->loop_count
		233
		234	Return the number of times the event loop has polled for new
		235	events. Sometiems useful as a generation counter.
		236
122	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)	237	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		238
		239	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
123		240
124	This function rolls together an I/O and a timer watcher for a single	241	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.	242	one-shot event without the need for managing a watcher object.
126		243
127	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>	244	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	250	If timeout is C<undef> or negative, then there will be no
134	timeout. Otherwise a EV::timer with this value will be started.	251	timeout. Otherwise a EV::timer with this value will be started.
135		252
136	When an error occurs or either the timeout or I/O watcher triggers, then	253	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	254	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>,	255	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
139	C<EV::WRITE> and C<EV::TIMEOUT>).	256	C<EV::WRITE> and C<EV::TIMEOUT>).
140		257
141	EV::once doesn't return anything: the watchers stay active till either	258	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	259	of them triggers, then they will be stopped and freed, and the callback
143	invoked.	260	invoked.
144		261
145	=back	262	=item EV::feed_fd_event ($fd, $revents)
146		263
147	=head2 WATCHER	264	=item $loop->feed_fd_event ($fd, $revents)
		265
		266	Feed an event on a file descriptor into EV. EV will react to this call as
		267	if the readyness notifications specified by C<$revents> (a combination of
		268	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		269
		270	=item EV::feed_signal_event ($signal)
		271
		272	Feed a signal event into EV. EV will react to this call as if the signal
		273	specified by C<$signal> had occured.
		274
		275	=item EV::set_io_collect_interval $time
		276
		277	=item $loop->set_io_collect_interval ($time)
		278
		279	=item EV::set_timeout_collect_interval $time
		280
		281	=item $loop->set_timeout_collect_interval ($time)
		282
		283	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		284	wait interval for timer events. See the libev documentation at
		285	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		286	a more detailed discussion.
		287
		288	=back
		289
		290
		291	=head1 WATCHER OBJECTS
148		292
149	A watcher is an object that gets created to record your interest in some	293	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	294	event. For instance, if you want to wait for STDIN to become readable, you
151	would create an EV::io watcher for that:	295	would create an EV::io watcher for that:
152		296
153	my $watcher = EV::io *STDIN, EV::READ, sub {	297	my $watcher = EV::io *STDIN, EV::READ, sub {
154	my ($watcher, $revents) = @_;	298	my ($watcher, $revents) = @_;
155	warn "yeah, STDIN should not be readable without blocking!\n"	299	warn "yeah, STDIN should now be readable without blocking!\n"
156	};	300	};
157		301
158	All watchers can be active (waiting for events) or inactive (paused). Only	302	All watchers can be active (waiting for events) or inactive (paused). Only
159	active watchers will have their callbacks invoked. All callbacks will be	303	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	304	called with at least two arguments: the watcher and a bitmask of received
161	events.	305	events.
162		306
163	Each watcher type has its associated bit in revents, so you can use the	307	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	308	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,	309	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	310	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	311	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
168	uses EV::TIMEOUT).	312	uses EV::TIMEOUT).
169		313
170	In the rare case where one wants to create a watcher but not start it at	314	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	315	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
177		321
178	Also, all methods changing some aspect of a watcher (->set, ->priority,	322	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,	323	->fh and so on) automatically stop and start it again if it is active,
180	which means pending events get lost.	324	which means pending events get lost.
181		325
182	=head2 WATCHER TYPES	326	=head2 COMMON WATCHER METHODS
183		327
184	Now lets move to the existing watcher types and asociated methods.	328	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		329
191	=over 4	330	=over 4
192		331
193	=item $w->start	332	=item $w->start
194		333
…		…
198		337
199	=item $w->stop	338	=item $w->stop
200		339
201	Stop a watcher if it is active. Also clear any pending events (events that	340	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),	341	have been received but that didn't yet result in a callback invocation),
203	regardless of wether the watcher was active or not.	342	regardless of whether the watcher was active or not.
204		343
205	=item $bool = $w->is_active	344	=item $bool = $w->is_active
206		345
207	Returns true if the watcher is active, false otherwise.	346	Returns true if the watcher is active, false otherwise.
208		347
…		…
233	watchers with higher priority will be invoked first. The valid range of	372	watchers with higher priority will be invoked first. The valid range of
234	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	373	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
235	-2). If the priority is outside this range it will automatically be	374	-2). If the priority is outside this range it will automatically be
236	normalised to the nearest valid priority.	375	normalised to the nearest valid priority.
237		376
238	The default priority of any newly-created weatcher is 0.	377	The default priority of any newly-created watcher is 0.
239		378
		379	Note that the priority semantics have not yet been fleshed out and are
		380	subject to almost certain change.
		381
240	=item $w->trigger ($revents)	382	=item $w->invoke ($revents)
241		383
242	Call the callback now with the given event mask.	384	Call the callback now with the given event mask.
243		385
		386	=item $w->feed_event ($revents)
		387
		388	Feed some events on this watcher into EV. EV will react to this call as if
		389	the watcher had received the given C<$revents> mask.
		390
		391	=item $revents = $w->clear_pending
		392
		393	If the watcher is pending, this function clears its pending status and
		394	returns its C<$revents> bitset (as if its callback was invoked). If the
		395	watcher isn't pending it does nothing and returns C<0>.
		396
		397	=item $previous_state = $w->keepalive ($bool)
		398
		399	Normally, C<EV::loop> will return when there are no active watchers
		400	(which is a "deadlock" because no progress can be made anymore). This is
		401	convinient because it allows you to start your watchers (and your jobs),
		402	call C<EV::loop> once and when it returns you know that all your jobs are
		403	finished (or they forgot to register some watchers for their task :).
		404
		405	Sometimes, however, this gets in your way, for example when the module
		406	that calls C<EV::loop> (usually the main program) is not the same module
		407	as a long-living watcher (for example a DNS client module written by
		408	somebody else even). Then you might want any outstanding requests to be
		409	handled, but you would not want to keep C<EV::loop> from returning just
		410	because you happen to have this long-running UDP port watcher.
		411
		412	In this case you can clear the keepalive status, which means that even
		413	though your watcher is active, it won't keep C<EV::loop> from returning.
		414
		415	The initial value for keepalive is true (enabled), and you cna change it
		416	any time.
		417
		418	Example: Register an I/O watcher for some UDP socket but do not keep the
		419	event loop from running just because of that watcher.
		420
		421	my $udp_socket = ...
		422	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		423	$udp_watcher->keepalive (0);
		424
		425	=item $loop = $w->loop
		426
		427	Return the loop that this watcher is attached to.
		428
		429	=back
		430
		431
		432	=head1 WATCHER TYPES
		433
		434	Each of the following subsections describes a single watcher type.
		435
		436	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		437
		438	=over 4
244		439
245	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	440	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
246		441
247	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	442	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
248		443
		444	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		445
		446	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		447
249	As long as the returned watcher object is alive, call the C<$callback>	448	As long as the returned watcher object is alive, call the C<$callback>
250	when the events specified in C<$eventmask>.	449	when at least one of events specified in C<$eventmask> occurs.
251		450
252	The $eventmask can be one or more of these constants ORed together:	451	The $eventmask can be one or more of these constants ORed together:
253		452
254	EV::READ wait until read() wouldn't block anymore	453	EV::READ wait until read() wouldn't block anymore
255	EV::WRITE wait until write() wouldn't block anymore	454	EV::WRITE wait until write() wouldn't block anymore
…		…
271		470
272	=item $old_eventmask = $w->events ($new_eventmask)	471	=item $old_eventmask = $w->events ($new_eventmask)
273		472
274	Returns the previously set event mask and optionally set a new one.	473	Returns the previously set event mask and optionally set a new one.
275		474
		475	=back
		476
		477
		478	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		479
		480	=over 4
276		481
277	=item $w = EV::timer $after, $repeat, $callback	482	=item $w = EV::timer $after, $repeat, $callback
278		483
279	=item $w = EV::timer_ns $after, $repeat, $callback	484	=item $w = EV::timer_ns $after, $repeat, $callback
280		485
281	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	486	=item $w = $loop->timer ($after, $repeat, $callback)
282	the timer will be restarted (with the $repeat value as $after) after the	487
283	callback returns.	488	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		489
		490	Calls the callback after C<$after> seconds (which may be fractional). If
		491	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		492	value as $after) after the callback returns.
284		493
285	This means that the callback would be called roughly after C<$after>	494	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	495	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	496	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,	497	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
294		503
295	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	504	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
296		505
297	=item $w->set ($after, $repeat)	506	=item $w->set ($after, $repeat)
298		507
299	Reconfigures the watcher, see the constructor above for details. Can be at	508	Reconfigures the watcher, see the constructor above for details. Can be called at
300	any time.	509	any time.
301		510
302	=item $w->again	511	=item $w->again
303		512
304	Similar to the C<start> method, but has special semantics for repeating timers:	513	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
315	This behaviour is useful when you have a timeout for some IO	524	This behaviour is useful when you have a timeout for some IO
316	operation. You create a timer object with the same value for C<$after> and	525	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	526	C<$repeat>, and then, in the read/write watcher, run the C<again> method
318	on the timeout.	527	on the timeout.
319		528
		529	=back
		530
		531
		532	=head3 PERIODIC WATCHERS - to cron or not to cron?
		533
		534	=over 4
320		535
321	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	536	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
322		537
323	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	538	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		539
		540	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		541
		542	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
324		543
325	Similar to EV::timer, but is not based on relative timeouts but on	544	Similar to EV::timer, but is not based on relative timeouts but on
326	absolute times. Apart from creating "simple" timers that trigger "at" the	545	absolute times. Apart from creating "simple" timers that trigger "at" the
327	specified time, it can also be used for non-drifting absolute timers and	546	specified time, it can also be used for non-drifting absolute timers and
328	more complex, cron-like, setups that are not adversely affected by time	547	more complex, cron-like, setups that are not adversely affected by time
…		…
338	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	557	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
339	will not adjust when a time jump occurs, that is, if it is to be run	558	will not adjust when a time jump occurs, that is, if it is to be run
340	at January 1st 2011 then it will run when the system time reaches or	559	at January 1st 2011 then it will run when the system time reaches or
341	surpasses this time.	560	surpasses this time.
342		561
343	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	562	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
344		563
345	In this mode the watcher will always be scheduled to time out at the	564	In this mode the watcher will always be scheduled to time out at the
346	next C<$at + N * $interval> time (for some integer N) and then repeat,	565	next C<$at + N * $interval> time (for some integer N) and then repeat,
347	regardless of any time jumps.	566	regardless of any time jumps.
348		567
…		…
366	time the periodic watcher gets scheduled, the reschedule callback	585	time the periodic watcher gets scheduled, the reschedule callback
367	($reschedule_cb) will be called with the watcher as first, and the current	586	($reschedule_cb) will be called with the watcher as first, and the current
368	time as second argument.	587	time as second argument.
369		588
370	I<This callback MUST NOT stop or destroy this or any other periodic	589	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	590	watcher, ever, and MUST NOT call any event loop functions or methods>. If
372	afterwards.	591	you need to stop it, return 1e30 and stop it afterwards. You may create
		592	and start a C<EV::prepare> watcher for this task.
373		593
374	It must return the next time to trigger, based on the passed time value	594	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	595	(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	596	argument). It will usually be called just before the callback will be
377	might be called at other times, too.	597	triggered, but might be called at other times, too.
378		598
379	This can be used to create very complex timers, such as a timer that	599	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	600	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	601	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	602	in about the same space (without requiring elaborate modules), drop me a
…		…
396		616
397	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	617	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
398		618
399	=item $w->set ($at, $interval, $reschedule_cb)	619	=item $w->set ($at, $interval, $reschedule_cb)
400		620
401	Reconfigures the watcher, see the constructor above for details. Can be at	621	Reconfigures the watcher, see the constructor above for details. Can be called at
402	any time.	622	any time.
403		623
404	=item $w->again	624	=item $w->again
405		625
406	Simply stops and starts the watcher again.	626	Simply stops and starts the watcher again.
407		627
		628	=item $time = $w->at
		629
		630	Return the time that the watcher is expected to trigger next.
		631
		632	=back
		633
		634
		635	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		636
		637	=over 4
408		638
409	=item $w = EV::signal $signal, $callback	639	=item $w = EV::signal $signal, $callback
410		640
411	=item $w = EV::signal_ns $signal, $callback	641	=item $w = EV::signal_ns $signal, $callback
412		642
413	Call the callback when $signal is received (the signal can be specified	643	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).	644	number or by name, just as with C<kill> or C<%SIG>).
415		645
416	EV will grab the signal for the process (the kernel only allows one	646	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,	647	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	648	and removes it again when you stop it. Perl does the same when you
419	add/remove callbacks to %SIG, so watch out.	649	add/remove callbacks to C<%SIG>, so watch out.
420		650
421	You can have as many signal watchers per signal as you want.	651	You can have as many signal watchers per signal as you want.
422		652
423	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	653	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
424		654
425	=item $w->set ($signal)	655	=item $w->set ($signal)
426		656
427	Reconfigures the watcher, see the constructor above for details. Can be at	657	Reconfigures the watcher, see the constructor above for details. Can be
428	any time.	658	called at any time.
429		659
430	=item $current_signum = $w->signal	660	=item $current_signum = $w->signal
431		661
432	=item $old_signum = $w->signal ($new_signal)	662	=item $old_signum = $w->signal ($new_signal)
433		663
434	Returns the previously set signal (always as a number not name) and	664	Returns the previously set signal (always as a number not name) and
435	optionally set a new one.	665	optionally set a new one.
436		666
		667	=back
437		668
		669
		670	=head3 CHILD WATCHERS - watch out for process status changes
		671
		672	=over 4
		673
438	=item $w = EV::child $pid, $callback	674	=item $w = EV::child $pid, $trace, $callback
439		675
440	=item $w = EV::child_ns $pid, $callback	676	=item $w = EV::child_ns $pid, $trace, $callback
		677
		678	=item $w = $loop->child ($pid, $trace, $callback)
		679
		680	=item $w = $loop->child_ns ($pid, $trace, $callback)
441		681
442	Call the callback when a status change for pid C<$pid> (or any pid	682	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	683	if C<$pid> is 0) has been received (a status change happens when the
		684	process terminates or is killed, or, when trace is true, additionally when
		685	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	686	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
445	changed/zombie children and call the callback.	687	changed/zombie children and call the callback.
446		688
447	You can access both status and pid by using the C<rstatus> and C<rpid>	689	It is valid (and fully supported) to install a child watcher after a child
448	methods on the watcher object.	690	has exited but before the event loop has started its next iteration (for
		691	example, first you C<fork>, then the new child process might exit, and
		692	only then do you install a child watcher in the parent for the new pid).
449		693
		694	You can access both exit (or tracing) status and pid by using the
		695	C<rstatus> and C<rpid> methods on the watcher object.
		696
450	You can have as many pid watchers per pid as you want.	697	You can have as many pid watchers per pid as you want, they will all be
		698	called.
451		699
452	The C<child_ns> variant doesn't start (activate) the newly created watcher.	700	The C<child_ns> variant doesn't start (activate) the newly created watcher.
453		701
454	=item $w->set ($pid)	702	=item $w->set ($pid, $trace)
455		703
456	Reconfigures the watcher, see the constructor above for details. Can be at	704	Reconfigures the watcher, see the constructor above for details. Can be called at
457	any time.	705	any time.
458		706
459	=item $current_pid = $w->pid	707	=item $current_pid = $w->pid
460
461	=item $old_pid = $w->pid ($new_pid)
462		708
463	Returns the previously set process id and optionally set a new one.	709	Returns the previously set process id and optionally set a new one.
464		710
465	=item $exit_status = $w->rstatus	711	=item $exit_status = $w->rstatus
466		712
…		…
470	=item $pid = $w->rpid	716	=item $pid = $w->rpid
471		717
472	Return the pid of the awaited child (useful when you have installed a	718	Return the pid of the awaited child (useful when you have installed a
473	watcher for all pids).	719	watcher for all pids).
474		720
		721	=back
		722
		723
		724	=head3 STAT WATCHERS - did the file attributes just change?
		725
		726	=over 4
		727
		728	=item $w = EV::stat $path, $interval, $callback
		729
		730	=item $w = EV::stat_ns $path, $interval, $callback
		731
		732	=item $w = $loop->stat ($path, $interval, $callback)
		733
		734	=item $w = $loop->stat_ns ($path, $interval, $callback)
		735
		736	Call the callback when a file status change has been detected on
		737	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		738	to "path does not exist" is a status change like any other.
		739
		740	The C<$interval> is a recommended polling interval for systems where
		741	OS-supported change notifications don't exist or are not supported. If
		742	you use C<0> then an unspecified default is used (which is highly
		743	recommended!), which is to be expected to be around five seconds usually.
		744
		745	This watcher type is not meant for massive numbers of stat watchers,
		746	as even with OS-supported change notifications, this can be
		747	resource-intensive.
		748
		749	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		750
		751	=item ... = $w->stat
		752
		753	This call is very similar to the perl C<stat> built-in: It stats (using
		754	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		755	well as EV's idea of the current stat values) to the values found.
		756
		757	In scalar context, a boolean is return indicating success or failure of
		758	the stat. In list context, the same 13-value list as with stat is returned
		759	(except that the blksize and blocks fields are not reliable).
		760
		761	In the case of an error, errno is set to C<ENOENT> (regardless of the
		762	actual error value) and the C<nlink> value is forced to zero (if the stat
		763	was successful then nlink is guaranteed to be non-zero).
		764
		765	See also the next two entries for more info.
		766
		767	=item ... = $w->attr
		768
		769	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		770	the values most recently detected by EV. See the next entry for more info.
		771
		772	=item ... = $w->prev
		773
		774	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		775	the previous set of values, before the change.
		776
		777	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		778	to the values found I<before> a change was detected, while C<< $w->attr >>
		779	returns the values found leading to the change detection. The difference (if any)
		780	between C<prev> and C<attr> is what triggered the callback.
		781
		782	If you did something to the filesystem object and do not want to trigger
		783	yet another change, you can call C<stat> to update EV's idea of what the
		784	current attributes are.
		785
		786	=item $w->set ($path, $interval)
		787
		788	Reconfigures the watcher, see the constructor above for details. Can be
		789	called at any time.
		790
		791	=item $current_path = $w->path
		792
		793	=item $old_path = $w->path ($new_path)
		794
		795	Returns the previously set path and optionally set a new one.
		796
		797	=item $current_interval = $w->interval
		798
		799	=item $old_interval = $w->interval ($new_interval)
		800
		801	Returns the previously set interval and optionally set a new one. Can be
		802	used to query the actual interval used.
		803
		804	=back
		805
		806
		807	=head3 IDLE WATCHERS - when you've got nothing better to do...
		808
		809	=over 4
475		810
476	=item $w = EV::idle $callback	811	=item $w = EV::idle $callback
477		812
478	=item $w = EV::idle_ns $callback	813	=item $w = EV::idle_ns $callback
479		814
480	Call the callback when there are no pending io, timer/periodic, signal or	815	=item $w = $loop->idle ($callback)
481	child events, i.e. when the process is idle.	816
		817	=item $w = $loop->idle_ns ($callback)
		818
		819	Call the callback when there are no other pending watchers of the same or
		820	higher priority (excluding check, prepare and other idle watchers of the
		821	same or lower priority, of course). They are called idle watchers because
		822	when the watcher is the highest priority pending event in the process, the
		823	process is considered to be idle at that priority.
		824
		825	If you want a watcher that is only ever called when I<no> other events are
		826	outstanding you have to set the priority to C<EV::MINPRI>.
482		827
483	The process will not block as long as any idle watchers are active, and	828	The process will not block as long as any idle watchers are active, and
484	they will be called repeatedly until stopped.	829	they will be called repeatedly until stopped.
485		830
		831	For example, if you have idle watchers at priority C<0> and C<1>, and
		832	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		833	and the I/O watcher will always run when ready. Only when the idle watcher
		834	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		835	pending with the C<0>-priority idle watcher be invoked.
		836
486	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	837	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
487		838
		839	=back
		840
		841
		842	=head3 PREPARE WATCHERS - customise your event loop!
		843
		844	=over 4
488		845
489	=item $w = EV::prepare $callback	846	=item $w = EV::prepare $callback
490		847
491	=item $w = EV::prepare_ns $callback	848	=item $w = EV::prepare_ns $callback
		849
		850	=item $w = $loop->prepare ($callback)
		851
		852	=item $w = $loop->prepare_ns ($callback)
492		853
493	Call the callback just before the process would block. You can still	854	Call the callback just before the process would block. You can still
494	create/modify any watchers at this point.	855	create/modify any watchers at this point.
495		856
496	See the EV::check watcher, below, for explanations and an example.	857	See the EV::check watcher, below, for explanations and an example.
497		858
498	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	859	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
499		860
		861	=back
		862
		863
		864	=head3 CHECK WATCHERS - customise your event loop even more!
		865
		866	=over 4
500		867
501	=item $w = EV::check $callback	868	=item $w = EV::check $callback
502		869
503	=item $w = EV::check_ns $callback	870	=item $w = EV::check_ns $callback
		871
		872	=item $w = $loop->check ($callback)
		873
		874	=item $w = $loop->check_ns ($callback)
504		875
505	Call the callback just after the process wakes up again (after it has	876	Call the callback just after the process wakes up again (after it has
506	gathered events), but before any other callbacks have been invoked.	877	gathered events), but before any other callbacks have been invoked.
507		878
508	This is used to integrate other event-based software into the EV	879	This is used to integrate other event-based software into the EV
…		…
518	or return;	889	or return;
519		890
520	# make the dispatcher handle any outstanding stuff	891	# make the dispatcher handle any outstanding stuff
521	... not shown	892	... not shown
522		893
523	# create an IO watcher for each and every socket	894	# create an I/O watcher for each and every socket
524	@snmp_watcher = (	895	@snmp_watcher = (
525	(map { EV::io $_, EV::READ, sub { } }	896	(map { EV::io $_, EV::READ, sub { } }
526	keys %{ $dispatcher->{_descriptors} }),	897	keys %{ $dispatcher->{_descriptors} }),
527		898
528	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	899	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
549	first).	920	first).
550		921
551	The C<check_ns> variant doesn't start (activate) the newly created watcher.	922	The C<check_ns> variant doesn't start (activate) the newly created watcher.
552		923
553	=back	924	=back
		925
		926
		927	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		928
		929	Fork watchers are called when a C<fork ()> was detected. The invocation
		930	is done before the event loop blocks next and before C<check> watchers
		931	are being called, and only in the child after the fork.
		932
		933	=over 4
		934
		935	=item $w = EV::fork $callback
		936
		937	=item $w = EV::fork_ns $callback
		938
		939	=item $w = $loop->fork ($callback)
		940
		941	=item $w = $loop->fork_ns ($callback)
		942
		943	Call the callback before the event loop is resumed in the child process
		944	after a fork.
		945
		946	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		947
		948	=back
		949
		950
		951	=head3 EMBED WATCHERS - when one backend isn't enough...
		952
		953	This is a rather advanced watcher type that lets you embed one event loop
		954	into another (currently only IO events are supported in the embedded
		955	loop, other types of watchers might be handled in a delayed or incorrect
		956	fashion and must not be used).
		957
		958	See the libev documentation at
		959	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		960	for more details.
		961
		962	In short, this watcher is most useful on BSD systems without working
		963	kqueue to still be able to handle a large number of sockets:
		964
		965	my $socket_loop;
		966
		967	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		968	if (
		969	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		970	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		971	) {
		972	# use kqueue for sockets
		973	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		974	}
		975
		976	# use the default loop otherwise
		977	$socket_loop \|\|= EV::default_loop;
		978
		979	=over 4
		980
		981	=item $w = EV::embed $otherloop[, $callback]
		982
		983	=item $w = EV::embed_ns $otherloop[, $callback]
		984
		985	=item $w = $loop->embed ($otherloop[, $callback])
		986
		987	=item $w = $loop->embed_ns ($otherloop[, $callback])
		988
		989	Call the callback when the embedded event loop (C<$otherloop>) has any
		990	I/O activity. The C<$callback> is optional: if it is missing, then the
		991	embedded event loop will be managed automatically (which is recommended),
		992	otherwise you have to invoke C<sweep> yourself.
		993
		994	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		995
		996	=back
		997
		998	=head3 ASYNC WATCHERS - how to wake up another event loop
		999
		1000	Async watchers are provided by EV, but have little use in perl directly, as perl
		1001	neither supports threads nor direct access to signal handlers or other
		1002	contexts where they could be of value.
		1003
		1004	It is, however, possible to use them from the XS level.
		1005
		1006	Please see the libev documentation for further details.
		1007
		1008	=over 4
		1009
		1010	=item $w = EV::async $callback
		1011
		1012	=item $w = EV::async_ns $callback
		1013
		1014	=item $w->send
		1015
		1016	=item $bool = $w->async_pending
		1017
		1018	=back
		1019
		1020
		1021	=head1 PERL SIGNALS
		1022
		1023	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1024	with EV is as the same as any other C library: Perl-signals will only be
		1025	handled when Perl runs, which means your signal handler might be invoked
		1026	only the next time an event callback is invoked.
		1027
		1028	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1029	ensure proper operations with regards to other event watchers.
		1030
		1031	If you cannot do this for whatever reason, you can also force a watcher
		1032	to be called on every event loop iteration by installing a C<EV::check>
		1033	watcher:
		1034
		1035	my $async_check = EV::check sub { };
		1036
		1037	This ensures that perl gets into control for a short time to handle any
		1038	pending signals, and also ensures (slightly) slower overall operation.
554		1039
555	=head1 THREADS	1040	=head1 THREADS
556		1041
557	Threads are not supported by this module in any way. Perl pseudo-threads	1042	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	1043	is evil stuff and must die. As soon as Perl gains real threads I will work
…		…
580	our $DIED = sub {	1065	our $DIED = sub {
581	warn "EV: error in callback (ignoring): $@";	1066	warn "EV: error in callback (ignoring): $@";
582	};	1067	};
583		1068
584	default_loop	1069	default_loop
585	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1070	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
586		1071
587	1;	1072	1;
588		1073
589	=head1 SEE ALSO	1074	=head1 SEE ALSO
590		1075
591	L<EV::DNS>.	1076	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1077	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1078	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1079	event-loop agnostic and portable event driven programming.
592		1080
593	=head1 AUTHOR	1081	=head1 AUTHOR
594		1082
595	Marc Lehmann <schmorp@schmorp.de>	1083	Marc Lehmann <schmorp@schmorp.de>
596	http://home.schmorp.de/	1084	http://home.schmorp.de/
597		1085
598	=cut	1086	=cut
599		1087

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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 1.101 by root, Sat Jul 12 22:19:22 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 1.101 by root, Sat Jul 12 22:19:22 2008 UTC