[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 1.99 by root, Tue Jul 8 09:37:37 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
59	use strict;	76	use strict;
60		77
61	BEGIN {	78	BEGIN {
62	our $VERSION = '1.2';	79	our $VERSION = '3.42';
63	use XSLoader;	80	use XSLoader;
64	XSLoader::load "EV", $VERSION;	81	XSLoader::load "EV", $VERSION;
65	}	82	}
66		83
67	@EV::Io::ISA =	84	@EV::IO::ISA =
68	@EV::Timer::ISA =	85	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	86	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	87	@EV::Signal::ISA =
		88	@EV::Child::ISA =
		89	@EV::Stat::ISA =
71	@EV::Idle::ISA =	90	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	91	@EV::Prepare::ISA =
73	@EV::Check::ISA =	92	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	93	@EV::Embed::ISA =
		94	@EV::Fork::ISA =
		95	@EV::Async::ISA =
		96	"EV::Watcher";
		97
		98	@EV::Loop::Default::ISA = "EV::Loop";
		99
		100	=head1 EVENT LOOPS
		101
		102	EV supports multiple event loops: There is a single "default event loop"
		103	that can handle everything including signals and child watchers, and any
		104	number of "dynamic event loops" that can use different backends (with
		105	various limitations), but no child and signal watchers.
		106
		107	You do not have to do anything to create the default event loop: When
		108	the module is loaded a suitable backend is selected on the premise of
		109	selecting a working backend (which for example rules out kqueue on most
		110	BSDs). Modules should, unless they have "special needs" always use the
		111	default loop as this is fastest (perl-wise), best supported by other
		112	modules (e.g. AnyEvent or Coro) and most portable event loop.
		113
		114	For specific programs you can create additional event loops dynamically.
		115
		116	If you want to take avdantage of kqueue (which often works properly for
		117	sockets only) even though the default loop doesn't enable it, you can
		118	I<embed> a kqueue loop into the default loop: running the default loop
		119	will then also service the kqueue loop to some extent. See the example in
		120	the section about embed watchers for an example on how to achieve that.
		121
		122	=over 4
		123
		124	=item $loop = new EV::loop [$flags]
		125
		126	Create a new event loop as per the specified flags. Please refer to the
		127	C<ev_loop_new ()> function description in the libev documentation
		128	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		129	for more info.
		130
		131	The loop will automatically be destroyed when it is no longer referenced
		132	by any watcher and the loop object goes out of scope.
		133
		134	Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
		135	is protected by this module.
		136
		137	=item $loop->loop_fork
		138
		139	Must be called after a fork in the child, before entering or continuing
		140	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		141	this function automatically, at some performance loss (refer to the libev
		142	documentation).
		143
		144	=item $loop->loop_verify
		145
		146	Calls C<ev_verify> to make internal consistency checks (for debugging
		147	libev) and abort the program if any data structures were found to be
		148	corrupted.
		149
		150	=item $loop = EV::default_loop [$flags]
		151
		152	Return the default loop (which is a singleton object). Since this module
		153	already creates the default loop with default flags, specifying flags here
		154	will not have any effect unless you destroy the default loop first, which
		155	isn't supported. So in short: don't do it, and if you break it, you get to
		156	keep the pieces.
		157
		158	=back
		159
75		160
76	=head1 BASIC INTERFACE	161	=head1 BASIC INTERFACE
77		162
78	=over 4	163	=over 4
79		164
80	=item $EV::DIED	165	=item $EV::DIED
81		166
82	Must contain a reference to a function that is called when a callback	167	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	168	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	169	informative message and continues.
85		170
86	If this callback throws an exception it will be silently ignored.	171	If this callback throws an exception it will be silently ignored.
87		172
		173	=item $flags = EV::supported_backends
		174
		175	=item $flags = EV::recommended_backends
		176
		177	=item $flags = EV::embeddable_backends
		178
		179	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		180	instance of EV, the set of recommended backends (supposed to be good) for
		181	this platform and the set of embeddable backends (see EMBED WATCHERS).
		182
		183	=item EV::sleep $seconds
		184
		185	Block the process for the given number of (fractional) seconds.
		186
88	=item $time = EV::time	187	=item $time = EV::time
89		188
90	Returns the current time in (fractional) seconds since the epoch.	189	Returns the current time in (fractional) seconds since the epoch.
91		190
92	=item $time = EV::now	191	=item $time = EV::now
		192
		193	=item $time = $loop->now
93		194
94	Returns the time the last event loop iteration has been started. This	195	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	196	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	197	usually faster then calling EV::time.
97		198
98	=item $method = EV::method	199	=item $backend = EV::backend
		200
		201	=item $backend = $loop->backend
99		202
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	203	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	204	or EV::METHOD_EPOLL).
102		205
103	=item EV::loop [$flags]	206	=item EV::loop [$flags]
		207
		208	=item $loop->loop ([$flags])
104		209
105	Begin checking for events and calling callbacks. It returns when a	210	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	211	callback calls EV::unloop.
107		212
108	The $flags argument can be one of the following:	213	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	216	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	217	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		218
114	=item EV::unloop [$how]	219	=item EV::unloop [$how]
115		220
		221	=item $loop->unloop ([$how])
		222
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	223	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	224	innermost call to EV::loop return.
118		225
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	226	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	227	fast as possible.
121		228
		229	=item $count = EV::loop_count
		230
		231	=item $count = $loop->loop_count
		232
		233	Return the number of times the event loop has polled for new
		234	events. Sometiems useful as a generation counter.
		235
122	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)	236	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		237
		238	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
123		239
124	This function rolls together an I/O and a timer watcher for a single	240	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.	241	one-shot event without the need for managing a watcher object.
126		242
127	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>	243	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	249	If timeout is C<undef> or negative, then there will be no
134	timeout. Otherwise a EV::timer with this value will be started.	250	timeout. Otherwise a EV::timer with this value will be started.
135		251
136	When an error occurs or either the timeout or I/O watcher triggers, then	252	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	253	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>,	254	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
139	C<EV::WRITE> and C<EV::TIMEOUT>).	255	C<EV::WRITE> and C<EV::TIMEOUT>).
140		256
141	EV::once doesn't return anything: the watchers stay active till either	257	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	258	of them triggers, then they will be stopped and freed, and the callback
143	invoked.	259	invoked.
144		260
145	=back	261	=item EV::feed_fd_event ($fd, $revents)
146		262
147	=head2 WATCHER	263	=item $loop->feed_fd_event ($fd, $revents)
		264
		265	Feed an event on a file descriptor into EV. EV will react to this call as
		266	if the readyness notifications specified by C<$revents> (a combination of
		267	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		268
		269	=item EV::feed_signal_event ($signal)
		270
		271	Feed a signal event into EV. EV will react to this call as if the signal
		272	specified by C<$signal> had occured.
		273
		274	=item EV::set_io_collect_interval $time
		275
		276	=item $loop->set_io_collect_interval ($time)
		277
		278	=item EV::set_timeout_collect_interval $time
		279
		280	=item $loop->set_timeout_collect_interval ($time)
		281
		282	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		283	wait interval for timer events. See the libev documentation at
		284	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		285	a more detailed discussion.
		286
		287	=back
		288
		289
		290	=head1 WATCHER OBJECTS
148		291
149	A watcher is an object that gets created to record your interest in some	292	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	293	event. For instance, if you want to wait for STDIN to become readable, you
151	would create an EV::io watcher for that:	294	would create an EV::io watcher for that:
152		295
153	my $watcher = EV::io *STDIN, EV::READ, sub {	296	my $watcher = EV::io *STDIN, EV::READ, sub {
154	my ($watcher, $revents) = @_;	297	my ($watcher, $revents) = @_;
155	warn "yeah, STDIN should not be readable without blocking!\n"	298	warn "yeah, STDIN should now be readable without blocking!\n"
156	};	299	};
157		300
158	All watchers can be active (waiting for events) or inactive (paused). Only	301	All watchers can be active (waiting for events) or inactive (paused). Only
159	active watchers will have their callbacks invoked. All callbacks will be	302	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	303	called with at least two arguments: the watcher and a bitmask of received
161	events.	304	events.
162		305
163	Each watcher type has its associated bit in revents, so you can use the	306	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	307	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,	308	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	309	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	310	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
168	uses EV::TIMEOUT).	311	uses EV::TIMEOUT).
169		312
170	In the rare case where one wants to create a watcher but not start it at	313	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	314	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
177		320
178	Also, all methods changing some aspect of a watcher (->set, ->priority,	321	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,	322	->fh and so on) automatically stop and start it again if it is active,
180	which means pending events get lost.	323	which means pending events get lost.
181		324
182	=head2 WATCHER TYPES	325	=head2 COMMON WATCHER METHODS
183		326
184	Now lets move to the existing watcher types and asociated methods.	327	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		328
191	=over 4	329	=over 4
192		330
193	=item $w->start	331	=item $w->start
194		332
…		…
198		336
199	=item $w->stop	337	=item $w->stop
200		338
201	Stop a watcher if it is active. Also clear any pending events (events that	339	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),	340	have been received but that didn't yet result in a callback invocation),
203	regardless of wether the watcher was active or not.	341	regardless of whether the watcher was active or not.
204		342
205	=item $bool = $w->is_active	343	=item $bool = $w->is_active
206		344
207	Returns true if the watcher is active, false otherwise.	345	Returns true if the watcher is active, false otherwise.
208		346
…		…
233	watchers with higher priority will be invoked first. The valid range of	371	watchers with higher priority will be invoked first. The valid range of
234	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	372	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
235	-2). If the priority is outside this range it will automatically be	373	-2). If the priority is outside this range it will automatically be
236	normalised to the nearest valid priority.	374	normalised to the nearest valid priority.
237		375
238	The default priority of any newly-created weatcher is 0.	376	The default priority of any newly-created watcher is 0.
239		377
		378	Note that the priority semantics have not yet been fleshed out and are
		379	subject to almost certain change.
		380
240	=item $w->trigger ($revents)	381	=item $w->invoke ($revents)
241		382
242	Call the callback now with the given event mask.	383	Call the callback now with the given event mask.
243		384
		385	=item $w->feed_event ($revents)
		386
		387	Feed some events on this watcher into EV. EV will react to this call as if
		388	the watcher had received the given C<$revents> mask.
		389
		390	=item $revents = $w->clear_pending
		391
		392	If the watcher is pending, this function clears its pending status and
		393	returns its C<$revents> bitset (as if its callback was invoked). If the
		394	watcher isn't pending it does nothing and returns C<0>.
		395
		396	=item $previous_state = $w->keepalive ($bool)
		397
		398	Normally, C<EV::loop> will return when there are no active watchers
		399	(which is a "deadlock" because no progress can be made anymore). This is
		400	convinient because it allows you to start your watchers (and your jobs),
		401	call C<EV::loop> once and when it returns you know that all your jobs are
		402	finished (or they forgot to register some watchers for their task :).
		403
		404	Sometimes, however, this gets in your way, for example when the module
		405	that calls C<EV::loop> (usually the main program) is not the same module
		406	as a long-living watcher (for example a DNS client module written by
		407	somebody else even). Then you might want any outstanding requests to be
		408	handled, but you would not want to keep C<EV::loop> from returning just
		409	because you happen to have this long-running UDP port watcher.
		410
		411	In this case you can clear the keepalive status, which means that even
		412	though your watcher is active, it won't keep C<EV::loop> from returning.
		413
		414	The initial value for keepalive is true (enabled), and you cna change it
		415	any time.
		416
		417	Example: Register an I/O watcher for some UDP socket but do not keep the
		418	event loop from running just because of that watcher.
		419
		420	my $udp_socket = ...
		421	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		422	$udp_watcher->keepalive (0);
		423
		424	=item $loop = $w->loop
		425
		426	Return the loop that this watcher is attached to.
		427
		428	=back
		429
		430
		431	=head1 WATCHER TYPES
		432
		433	Each of the following subsections describes a single watcher type.
		434
		435	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		436
		437	=over 4
244		438
245	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	439	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
246		440
247	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	441	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
248		442
		443	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		444
		445	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		446
249	As long as the returned watcher object is alive, call the C<$callback>	447	As long as the returned watcher object is alive, call the C<$callback>
250	when the events specified in C<$eventmask>.	448	when at least one of events specified in C<$eventmask> occurs.
251		449
252	The $eventmask can be one or more of these constants ORed together:	450	The $eventmask can be one or more of these constants ORed together:
253		451
254	EV::READ wait until read() wouldn't block anymore	452	EV::READ wait until read() wouldn't block anymore
255	EV::WRITE wait until write() wouldn't block anymore	453	EV::WRITE wait until write() wouldn't block anymore
…		…
271		469
272	=item $old_eventmask = $w->events ($new_eventmask)	470	=item $old_eventmask = $w->events ($new_eventmask)
273		471
274	Returns the previously set event mask and optionally set a new one.	472	Returns the previously set event mask and optionally set a new one.
275		473
		474	=back
		475
		476
		477	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		478
		479	=over 4
276		480
277	=item $w = EV::timer $after, $repeat, $callback	481	=item $w = EV::timer $after, $repeat, $callback
278		482
279	=item $w = EV::timer_ns $after, $repeat, $callback	483	=item $w = EV::timer_ns $after, $repeat, $callback
280		484
281	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	485	=item $w = $loop->timer ($after, $repeat, $callback)
282	the timer will be restarted (with the $repeat value as $after) after the	486
283	callback returns.	487	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		488
		489	Calls the callback after C<$after> seconds (which may be fractional). If
		490	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		491	value as $after) after the callback returns.
284		492
285	This means that the callback would be called roughly after C<$after>	493	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	494	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	495	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,	496	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
294		502
295	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	503	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
296		504
297	=item $w->set ($after, $repeat)	505	=item $w->set ($after, $repeat)
298		506
299	Reconfigures the watcher, see the constructor above for details. Can be at	507	Reconfigures the watcher, see the constructor above for details. Can be called at
300	any time.	508	any time.
301		509
302	=item $w->again	510	=item $w->again
303		511
304	Similar to the C<start> method, but has special semantics for repeating timers:	512	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
315	This behaviour is useful when you have a timeout for some IO	523	This behaviour is useful when you have a timeout for some IO
316	operation. You create a timer object with the same value for C<$after> and	524	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	525	C<$repeat>, and then, in the read/write watcher, run the C<again> method
318	on the timeout.	526	on the timeout.
319		527
		528	=back
		529
		530
		531	=head3 PERIODIC WATCHERS - to cron or not to cron?
		532
		533	=over 4
320		534
321	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	535	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
322		536
323	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	537	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		538
		539	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		540
		541	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
324		542
325	Similar to EV::timer, but is not based on relative timeouts but on	543	Similar to EV::timer, but is not based on relative timeouts but on
326	absolute times. Apart from creating "simple" timers that trigger "at" the	544	absolute times. Apart from creating "simple" timers that trigger "at" the
327	specified time, it can also be used for non-drifting absolute timers and	545	specified time, it can also be used for non-drifting absolute timers and
328	more complex, cron-like, setups that are not adversely affected by time	546	more complex, cron-like, setups that are not adversely affected by time
…		…
338	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	556	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
339	will not adjust when a time jump occurs, that is, if it is to be run	557	will not adjust when a time jump occurs, that is, if it is to be run
340	at January 1st 2011 then it will run when the system time reaches or	558	at January 1st 2011 then it will run when the system time reaches or
341	surpasses this time.	559	surpasses this time.
342		560
343	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	561	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
344		562
345	In this mode the watcher will always be scheduled to time out at the	563	In this mode the watcher will always be scheduled to time out at the
346	next C<$at + N * $interval> time (for some integer N) and then repeat,	564	next C<$at + N * $interval> time (for some integer N) and then repeat,
347	regardless of any time jumps.	565	regardless of any time jumps.
348		566
…		…
366	time the periodic watcher gets scheduled, the reschedule callback	584	time the periodic watcher gets scheduled, the reschedule callback
367	($reschedule_cb) will be called with the watcher as first, and the current	585	($reschedule_cb) will be called with the watcher as first, and the current
368	time as second argument.	586	time as second argument.
369		587
370	I<This callback MUST NOT stop or destroy this or any other periodic	588	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	589	watcher, ever, and MUST NOT call any event loop functions or methods>. If
372	afterwards.	590	you need to stop it, return 1e30 and stop it afterwards. You may create
		591	and start a C<EV::prepare> watcher for this task.
373		592
374	It must return the next time to trigger, based on the passed time value	593	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	594	(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	595	argument). It will usually be called just before the callback will be
377	might be called at other times, too.	596	triggered, but might be called at other times, too.
378		597
379	This can be used to create very complex timers, such as a timer that	598	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	599	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	600	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	601	in about the same space (without requiring elaborate modules), drop me a
…		…
396		615
397	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	616	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
398		617
399	=item $w->set ($at, $interval, $reschedule_cb)	618	=item $w->set ($at, $interval, $reschedule_cb)
400		619
401	Reconfigures the watcher, see the constructor above for details. Can be at	620	Reconfigures the watcher, see the constructor above for details. Can be called at
402	any time.	621	any time.
403		622
404	=item $w->again	623	=item $w->again
405		624
406	Simply stops and starts the watcher again.	625	Simply stops and starts the watcher again.
407		626
		627	=item $time = $w->at
		628
		629	Return the time that the watcher is expected to trigger next.
		630
		631	=back
		632
		633
		634	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		635
		636	=over 4
408		637
409	=item $w = EV::signal $signal, $callback	638	=item $w = EV::signal $signal, $callback
410		639
411	=item $w = EV::signal_ns $signal, $callback	640	=item $w = EV::signal_ns $signal, $callback
412		641
413	Call the callback when $signal is received (the signal can be specified	642	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).	643	number or by name, just as with C<kill> or C<%SIG>).
415		644
416	EV will grab the signal for the process (the kernel only allows one	645	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,	646	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	647	and removes it again when you stop it. Perl does the same when you
419	add/remove callbacks to %SIG, so watch out.	648	add/remove callbacks to C<%SIG>, so watch out.
420		649
421	You can have as many signal watchers per signal as you want.	650	You can have as many signal watchers per signal as you want.
422		651
423	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	652	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
424		653
425	=item $w->set ($signal)	654	=item $w->set ($signal)
426		655
427	Reconfigures the watcher, see the constructor above for details. Can be at	656	Reconfigures the watcher, see the constructor above for details. Can be
428	any time.	657	called at any time.
429		658
430	=item $current_signum = $w->signal	659	=item $current_signum = $w->signal
431		660
432	=item $old_signum = $w->signal ($new_signal)	661	=item $old_signum = $w->signal ($new_signal)
433		662
434	Returns the previously set signal (always as a number not name) and	663	Returns the previously set signal (always as a number not name) and
435	optionally set a new one.	664	optionally set a new one.
436		665
		666	=back
437		667
		668
		669	=head3 CHILD WATCHERS - watch out for process status changes
		670
		671	=over 4
		672
438	=item $w = EV::child $pid, $callback	673	=item $w = EV::child $pid, $trace, $callback
439		674
440	=item $w = EV::child_ns $pid, $callback	675	=item $w = EV::child_ns $pid, $trace, $callback
		676
		677	=item $w = $loop->child ($pid, $trace, $callback)
		678
		679	=item $w = $loop->child_ns ($pid, $trace, $callback)
441		680
442	Call the callback when a status change for pid C<$pid> (or any pid	681	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	682	if C<$pid> is 0) has been received (a status change happens when the
		683	process terminates or is killed, or, when trace is true, additionally when
		684	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	685	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
445	changed/zombie children and call the callback.	686	changed/zombie children and call the callback.
446		687
447	You can access both status and pid by using the C<rstatus> and C<rpid>	688	It is valid (and fully supported) to install a child watcher after a child
448	methods on the watcher object.	689	has exited but before the event loop has started its next iteration (for
		690	example, first you C<fork>, then the new child process might exit, and
		691	only then do you install a child watcher in the parent for the new pid).
449		692
		693	You can access both exit (or tracing) status and pid by using the
		694	C<rstatus> and C<rpid> methods on the watcher object.
		695
450	You can have as many pid watchers per pid as you want.	696	You can have as many pid watchers per pid as you want, they will all be
		697	called.
451		698
452	The C<child_ns> variant doesn't start (activate) the newly created watcher.	699	The C<child_ns> variant doesn't start (activate) the newly created watcher.
453		700
454	=item $w->set ($pid)	701	=item $w->set ($pid, $trace)
455		702
456	Reconfigures the watcher, see the constructor above for details. Can be at	703	Reconfigures the watcher, see the constructor above for details. Can be called at
457	any time.	704	any time.
458		705
459	=item $current_pid = $w->pid	706	=item $current_pid = $w->pid
460
461	=item $old_pid = $w->pid ($new_pid)
462		707
463	Returns the previously set process id and optionally set a new one.	708	Returns the previously set process id and optionally set a new one.
464		709
465	=item $exit_status = $w->rstatus	710	=item $exit_status = $w->rstatus
466		711
…		…
470	=item $pid = $w->rpid	715	=item $pid = $w->rpid
471		716
472	Return the pid of the awaited child (useful when you have installed a	717	Return the pid of the awaited child (useful when you have installed a
473	watcher for all pids).	718	watcher for all pids).
474		719
		720	=back
		721
		722
		723	=head3 STAT WATCHERS - did the file attributes just change?
		724
		725	=over 4
		726
		727	=item $w = EV::stat $path, $interval, $callback
		728
		729	=item $w = EV::stat_ns $path, $interval, $callback
		730
		731	=item $w = $loop->stat ($path, $interval, $callback)
		732
		733	=item $w = $loop->stat_ns ($path, $interval, $callback)
		734
		735	Call the callback when a file status change has been detected on
		736	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		737	to "path does not exist" is a status change like any other.
		738
		739	The C<$interval> is a recommended polling interval for systems where
		740	OS-supported change notifications don't exist or are not supported. If
		741	you use C<0> then an unspecified default is used (which is highly
		742	recommended!), which is to be expected to be around five seconds usually.
		743
		744	This watcher type is not meant for massive numbers of stat watchers,
		745	as even with OS-supported change notifications, this can be
		746	resource-intensive.
		747
		748	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		749
		750	=item ... = $w->stat
		751
		752	This call is very similar to the perl C<stat> built-in: It stats (using
		753	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		754	well as EV's idea of the current stat values) to the values found.
		755
		756	In scalar context, a boolean is return indicating success or failure of
		757	the stat. In list context, the same 13-value list as with stat is returned
		758	(except that the blksize and blocks fields are not reliable).
		759
		760	In the case of an error, errno is set to C<ENOENT> (regardless of the
		761	actual error value) and the C<nlink> value is forced to zero (if the stat
		762	was successful then nlink is guaranteed to be non-zero).
		763
		764	See also the next two entries for more info.
		765
		766	=item ... = $w->attr
		767
		768	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		769	the values most recently detected by EV. See the next entry for more info.
		770
		771	=item ... = $w->prev
		772
		773	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		774	the previous set of values, before the change.
		775
		776	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		777	to the values found I<before> a change was detected, while C<< $w->attr >>
		778	returns the values found leading to the change detection. The difference (if any)
		779	between C<prev> and C<attr> is what triggered the callback.
		780
		781	If you did something to the filesystem object and do not want to trigger
		782	yet another change, you can call C<stat> to update EV's idea of what the
		783	current attributes are.
		784
		785	=item $w->set ($path, $interval)
		786
		787	Reconfigures the watcher, see the constructor above for details. Can be
		788	called at any time.
		789
		790	=item $current_path = $w->path
		791
		792	=item $old_path = $w->path ($new_path)
		793
		794	Returns the previously set path and optionally set a new one.
		795
		796	=item $current_interval = $w->interval
		797
		798	=item $old_interval = $w->interval ($new_interval)
		799
		800	Returns the previously set interval and optionally set a new one. Can be
		801	used to query the actual interval used.
		802
		803	=back
		804
		805
		806	=head3 IDLE WATCHERS - when you've got nothing better to do...
		807
		808	=over 4
475		809
476	=item $w = EV::idle $callback	810	=item $w = EV::idle $callback
477		811
478	=item $w = EV::idle_ns $callback	812	=item $w = EV::idle_ns $callback
479		813
480	Call the callback when there are no pending io, timer/periodic, signal or	814	=item $w = $loop->idle ($callback)
481	child events, i.e. when the process is idle.	815
		816	=item $w = $loop->idle_ns ($callback)
		817
		818	Call the callback when there are no other pending watchers of the same or
		819	higher priority (excluding check, prepare and other idle watchers of the
		820	same or lower priority, of course). They are called idle watchers because
		821	when the watcher is the highest priority pending event in the process, the
		822	process is considered to be idle at that priority.
		823
		824	If you want a watcher that is only ever called when I<no> other events are
		825	outstanding you have to set the priority to C<EV::MINPRI>.
482		826
483	The process will not block as long as any idle watchers are active, and	827	The process will not block as long as any idle watchers are active, and
484	they will be called repeatedly until stopped.	828	they will be called repeatedly until stopped.
485		829
		830	For example, if you have idle watchers at priority C<0> and C<1>, and
		831	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		832	and the I/O watcher will always run when ready. Only when the idle watcher
		833	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		834	pending with the C<0>-priority idle watcher be invoked.
		835
486	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	836	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
487		837
		838	=back
		839
		840
		841	=head3 PREPARE WATCHERS - customise your event loop!
		842
		843	=over 4
488		844
489	=item $w = EV::prepare $callback	845	=item $w = EV::prepare $callback
490		846
491	=item $w = EV::prepare_ns $callback	847	=item $w = EV::prepare_ns $callback
		848
		849	=item $w = $loop->prepare ($callback)
		850
		851	=item $w = $loop->prepare_ns ($callback)
492		852
493	Call the callback just before the process would block. You can still	853	Call the callback just before the process would block. You can still
494	create/modify any watchers at this point.	854	create/modify any watchers at this point.
495		855
496	See the EV::check watcher, below, for explanations and an example.	856	See the EV::check watcher, below, for explanations and an example.
497		857
498	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	858	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
499		859
		860	=back
		861
		862
		863	=head3 CHECK WATCHERS - customise your event loop even more!
		864
		865	=over 4
500		866
501	=item $w = EV::check $callback	867	=item $w = EV::check $callback
502		868
503	=item $w = EV::check_ns $callback	869	=item $w = EV::check_ns $callback
		870
		871	=item $w = $loop->check ($callback)
		872
		873	=item $w = $loop->check_ns ($callback)
504		874
505	Call the callback just after the process wakes up again (after it has	875	Call the callback just after the process wakes up again (after it has
506	gathered events), but before any other callbacks have been invoked.	876	gathered events), but before any other callbacks have been invoked.
507		877
508	This is used to integrate other event-based software into the EV	878	This is used to integrate other event-based software into the EV
…		…
518	or return;	888	or return;
519		889
520	# make the dispatcher handle any outstanding stuff	890	# make the dispatcher handle any outstanding stuff
521	... not shown	891	... not shown
522		892
523	# create an IO watcher for each and every socket	893	# create an I/O watcher for each and every socket
524	@snmp_watcher = (	894	@snmp_watcher = (
525	(map { EV::io $_, EV::READ, sub { } }	895	(map { EV::io $_, EV::READ, sub { } }
526	keys %{ $dispatcher->{_descriptors} }),	896	keys %{ $dispatcher->{_descriptors} }),
527		897
528	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	898	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
549	first).	919	first).
550		920
551	The C<check_ns> variant doesn't start (activate) the newly created watcher.	921	The C<check_ns> variant doesn't start (activate) the newly created watcher.
552		922
553	=back	923	=back
		924
		925
		926	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		927
		928	Fork watchers are called when a C<fork ()> was detected. The invocation
		929	is done before the event loop blocks next and before C<check> watchers
		930	are being called, and only in the child after the fork.
		931
		932	=over 4
		933
		934	=item $w = EV::fork $callback
		935
		936	=item $w = EV::fork_ns $callback
		937
		938	=item $w = $loop->fork ($callback)
		939
		940	=item $w = $loop->fork_ns ($callback)
		941
		942	Call the callback before the event loop is resumed in the child process
		943	after a fork.
		944
		945	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		946
		947	=back
		948
		949
		950	=head3 EMBED WATCHERS - when one backend isn't enough...
		951
		952	This is a rather advanced watcher type that lets you embed one event loop
		953	into another (currently only IO events are supported in the embedded
		954	loop, other types of watchers might be handled in a delayed or incorrect
		955	fashion and must not be used).
		956
		957	See the libev documentation at
		958	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		959	for more details.
		960
		961	In short, this watcher is most useful on BSD systems without working
		962	kqueue to still be able to handle a large number of sockets:
		963
		964	my $socket_loop;
		965
		966	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		967	if (
		968	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		969	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		970	) {
		971	# use kqueue for sockets
		972	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		973	}
		974
		975	# use the default loop otherwise
		976	$socket_loop \|\|= EV::default_loop;
		977
		978	=over 4
		979
		980	=item $w = EV::embed $otherloop, $callback
		981
		982	=item $w = EV::embed_ns $otherloop, $callback
		983
		984	=item $w = $loop->embed ($otherloop, $callback)
		985
		986	=item $w = $loop->embed_ns ($otherloop, $callback)
		987
		988	Call the callback when the embedded event loop (C<$otherloop>) has any
		989	I/O activity. The C<$callback> should alwas be specified as C<undef> in
		990	this version of EV, which means the embedded event loop will be managed
		991	automatically.
		992
		993	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		994
		995	=back
		996
		997	=head3 ASYNC WATCHERS - how to wake up another event loop
		998
		999	Async watchers are provided by EV, but have little use in perl directly, as perl
		1000	neither supports threads nor direct access to signal handlers or other
		1001	contexts where they could be of value.
		1002
		1003	It is, however, possible to use them from the XS level.
		1004
		1005	Please see the libev documentation for further details.
		1006
		1007	=over 4
		1008
		1009	=item $w = EV::async $callback
		1010
		1011	=item $w = EV::async_ns $callback
		1012
		1013	=item $w->send
		1014
		1015	=item $bool = $w->async_pending
		1016
		1017	=back
		1018
		1019
		1020	=head1 PERL SIGNALS
		1021
		1022	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1023	with EV is as the same as any other C library: Perl-signals will only be
		1024	handled when Perl runs, which means your signal handler might be invoked
		1025	only the next time an event callback is invoked.
		1026
		1027	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1028	ensure proper operations with regards to other event watchers.
		1029
		1030	If you cannot do this for whatever reason, you can also force a watcher
		1031	to be called on every event loop iteration by installing a C<EV::check>
		1032	watcher:
		1033
		1034	my $async_check = EV::check sub { };
		1035
		1036	This ensures that perl gets into control for a short time to handle any
		1037	pending signals, and also ensures (slightly) slower overall operation.
554		1038
555	=head1 THREADS	1039	=head1 THREADS
556		1040
557	Threads are not supported by this module in any way. Perl pseudo-threads	1041	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	1042	is evil stuff and must die. As soon as Perl gains real threads I will work
…		…
580	our $DIED = sub {	1064	our $DIED = sub {
581	warn "EV: error in callback (ignoring): $@";	1065	warn "EV: error in callback (ignoring): $@";
582	};	1066	};
583		1067
584	default_loop	1068	default_loop
585	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1069	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
586		1070
587	1;	1071	1;
588		1072
589	=head1 SEE ALSO	1073	=head1 SEE ALSO
590		1074
591	L<EV::DNS>.	1075	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1076	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1077	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1078	event-loop agnostic and portable event driven programming.
592		1079
593	=head1 AUTHOR	1080	=head1 AUTHOR
594		1081
595	Marc Lehmann <schmorp@schmorp.de>	1082	Marc Lehmann <schmorp@schmorp.de>
596	http://home.schmorp.de/	1083	http://home.schmorp.de/
597		1084
598	=cut	1085	=cut
599		1086

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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 1.99 by root, Tue Jul 8 09:37:37 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 1.99 by root, Tue Jul 8 09:37:37 2008 UTC