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

Comparing EV/EV.pm (file contents):
Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs.
Revision 1.79 by root, Sat Dec 22 16:37:07 2007 UTC

…		…
10		10
11	my $w = EV::timer 2, 0, sub {	11	my $w = EV::timer 2, 0, sub {
12	warn "is called after 2s";	12	warn "is called after 2s";
13	};	13	};
14		14
15	my $w = EV::timer 2, 1, sub {	15	my $w = EV::timer 2, 2, sub {
16	warn "is called roughly every 2s (repeat = 1)";	16	warn "is called roughly every 2s (repeat = 2)";
17	};	17	};
18		18
19	undef $w; # destroy event watcher again	19	undef $w; # destroy event watcher again
20		20
21	my $w = EV::periodic 0, 60, sub {	21	my $w = EV::periodic 0, 60, 0, sub {
22	warn "is called every minute, on the minute, exactly";	22	warn "is called every minute, on the minute, exactly";
23	};	23	};
24		24
25	# IO	25	# IO
26		26
27	my $w = EV::io *STDIN, EV::READ, sub {	27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $revents) = @_; # all callbacks get the watcher object and event mask	28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29	warn "stdin is readable, you entered: ", <STDIN>;	29	warn "stdin is readable, you entered: ", <STDIN>;
30	};	30	};
31		31
32	# SIGNALS	32	# SIGNALS
33		33
34	my $w = EV::signal 'QUIT', sub {	34	my $w = EV::signal 'QUIT', sub {
35	warn "sigquit received\n";	35	warn "sigquit received\n";
36	};	36	};
37		37
		38	# CHILD/PID STATUS CHANGES
		39
38	my $w = EV::signal 3, sub {	40	my $w = EV::child 666, sub {
39	warn "sigquit received (this is GNU/Linux, right?)\n";	41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
40	};	43	};
41		44
42	# CHILD/PID STATUS CHANGES	45	# STAT CHANGES
43		46	my $w = EV::stat "/etc/passwd", 10, sub {
44	my $w = EV::child 666, sub {
45	my ($w, $revents, $status) = @_;	47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
46	};	49	};
47		50
48	# MAINLOOP	51	# MAINLOOP
49	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
50	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
51	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
52		55
53	=head1 DESCRIPTION	56	=head1 DESCRIPTION
54		57
55	This module provides an interface to libev	58	This module provides an interface to libev
56	(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://cvs.schmorp.de/libev/ev.html>) for more subtle details on
		62	watcher semantics or some discussion on the available backends, or how to
		63	force a specific backend with C<LIBEV_FLAGS>, or just about in any case
		64	because it has much more detailed information.
57		65
58	=cut	66	=cut
59		67
60	package EV;	68	package EV;
61		69
62	use strict;	70	use strict;
63		71
64	BEGIN {	72	BEGIN {
65	our $VERSION = '0.1';	73	our $VERSION = '2.0';
66	use XSLoader;	74	use XSLoader;
67	XSLoader::load "EV", $VERSION;	75	XSLoader::load "EV", $VERSION;
68	}	76	}
69		77
70	@EV::Io::ISA =	78	@EV::IO::ISA =
71	@EV::Timer::ISA =	79	@EV::Timer::ISA =
72	@EV::Periodic::ISA =	80	@EV::Periodic::ISA =
73	@EV::Signal::ISA =	81	@EV::Signal::ISA =
		82	@EV::Child::ISA =
		83	@EV::Stat::ISA =
74	@EV::Idle::ISA =	84	@EV::Idle::ISA =
75	@EV::Prepare::ISA =	85	@EV::Prepare::ISA =
76	@EV::Check::ISA =	86	@EV::Check::ISA =
77	@EV::Child::ISA = "EV::Watcher";	87	@EV::Embed::ISA =
		88	@EV::Fork::ISA =
		89	"EV::Watcher";
		90
		91	@EV::Loop::Default::ISA = "EV::Loop";
		92
		93	=head1 EVENT LOOPS
		94
		95	EV supports multiple event loops: There is a single "default event loop"
		96	that can handle everything including signals and child watchers, and any
		97	number of "dynamic event loops" that can use different backends (with
		98	various limitations), but no child and signal watchers.
		99
		100	You do not have to do anything to create the default event loop: When
		101	the module is loaded a suitable backend is selected on the premise of
		102	selecting a working backend (which for example rules out kqueue on most
		103	BSDs). Modules should, unless they have "special needs" always use the
		104	default loop as this is fastest (perl-wise), best supported by other
		105	modules (e.g. AnyEvent or Coro) and most portable event loop.
		106
		107	For specific programs you can create additional event loops dynamically.
		108
		109	=over 4
		110
		111	=item $loop = new EV::loop [$flags]
		112
		113	Create a new event loop as per the specified flags. Please refer to the
		114	C<ev_loop_new ()> function description in the libev documentation
		115	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		116	for more info.
		117
		118	The loop will automatically be destroyed when it is no longer referenced
		119	by any watcher and the loop object goes out of scope.
		120
		121	Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
		122	is protected by this module.
		123
		124	=item $loop->loop_fork
		125
		126	Must be called after a fork in the child, before entering or continuing
		127	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		128	this fucntion automatically, at some performance loss (refer to the libev
		129	documentation).
		130
		131	=item $loop = EV::default_loop [$flags]
		132
		133	Return the default loop (which is a singleton object).
		134
		135	=back
		136
78		137
79	=head1 BASIC INTERFACE	138	=head1 BASIC INTERFACE
80		139
81	=over 4	140	=over 4
82		141
83	=item $EV::DIED	142	=item $EV::DIED
84		143
85	Must contain a reference to a function that is called when a callback	144	Must contain a reference to a function that is called when a callback
86	throws an exception (with $@ containing thr error). The default prints an	145	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	146	informative message and continues.
88		147
89	If this callback throws an exception it will be silently ignored.	148	If this callback throws an exception it will be silently ignored.
90		149
		150	=item $flags = EV::supported_backends
		151
		152	=item $flags = EV::recommended_backends
		153
		154	=item $flags = EV::embeddable_backends
		155
		156	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		157	instance of EV, the set of recommended backends (supposed to be good) for
		158	this platform and the set of embeddable backends (see EMBED WATCHERS).
		159
91	=item $time = EV::time	160	=item $time = EV::time
92		161
93	Returns the current time in (fractional) seconds since the epoch.	162	Returns the current time in (fractional) seconds since the epoch.
94		163
95	=item $time = EV::now	164	=item $time = EV::now
		165
		166	=item $time = $loop->now
96		167
97	Returns the time the last event loop iteration has been started. This	168	Returns the time the last event loop iteration has been started. This
98	is the time that (relative) timers are based on, and refering to it is	169	is the time that (relative) timers are based on, and refering to it is
99	usually faster then calling EV::time.	170	usually faster then calling EV::time.
100		171
101	=item $method = EV::ev_method	172	=item $backend = EV::backend
		173
		174	=item $backend = $loop->backend
102		175
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	176	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
104	or EV::METHOD_EPOLL).	177	or EV::METHOD_EPOLL).
105		178
106	=item EV::loop [$flags]	179	=item EV::loop [$flags]
107		180
		181	=item $loop->loop ([$flags])
		182
108	Begin checking for events and calling callbacks. It returns when a	183	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	184	callback calls EV::unloop.
110		185
111	The $flags argument can be one of the following:	186	The $flags argument can be one of the following:
112		187
113	0 as above	188	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	189	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	190	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		191
117	=item EV::loop_done [$how]	192	=item EV::unloop [$how]
118		193
		194	=item $loop->unloop ([$how])
		195
119	When called with no arguments or an argument of 1, makes the innermost	196	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	197	innermost call to EV::loop return.
121		198
122	When called with an agrument of 2, all calls to EV::loop will return as	199	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	200	fast as possible.
124		201
125	=back	202	=item $count = EV::loop_count
126		203
127	=head2 WATCHER	204	=item $count = $loop->loop_count
		205
		206	Return the number of times the event loop has polled for new
		207	events. Sometiems useful as a generation counter.
		208
		209	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		210
		211	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		212
		213	This function rolls together an I/O and a timer watcher for a single
		214	one-shot event without the need for managing a watcher object.
		215
		216	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		217	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		218	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		219	you do not want to wait for some I/O event, specify C<undef> for
		220	C<$fh_or_undef> and C<0> for C<$events>).
		221
		222	If timeout is C<undef> or negative, then there will be no
		223	timeout. Otherwise a EV::timer with this value will be started.
		224
		225	When an error occurs or either the timeout or I/O watcher triggers, then
		226	the callback will be called with the received event set (in general
		227	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		228	C<EV::WRITE> and C<EV::TIMEOUT>).
		229
		230	EV::once doesn't return anything: the watchers stay active till either
		231	of them triggers, then they will be stopped and freed, and the callback
		232	invoked.
		233
		234	=item EV::feed_fd_event ($fd, $revents)
		235
		236	=item $loop->feed_fd_event ($fd, $revents)
		237
		238	Feed an event on a file descriptor into EV. EV will react to this call as
		239	if the readyness notifications specified by C<$revents> (a combination of
		240	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		241
		242	=item EV::feed_signal_event ($signal)
		243
		244	Feed a signal event into EV. EV will react to this call as if the signal
		245	specified by C<$signal> had occured.
		246
		247	=item EV::set_io_collect_interval $time
		248
		249	=item $loop->set_io_collect_interval ($time)
		250
		251	=item EV::set_timeout_collect_interval $time
		252
		253	=item $loop->set_timeout_collect_interval ($time)
		254
		255	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		256	wait interval for timer events. See the libev documentation at
		257	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		258	a more detailed discussion.
		259
		260	=back
		261
		262
		263	=head1 WATCHER OBJECTS
128		264
129	A watcher is an object that gets created to record your interest in some	265	A watcher is an object that gets created to record your interest in some
130	event. For instance, if you want to wait for STDIN to become readable, you	266	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	267	would create an EV::io watcher for that:
132		268
133	my $watcher = EV::io *STDIN, EV::READ, sub {	269	my $watcher = EV::io *STDIN, EV::READ, sub {
134	my ($watcher, $revents) = @_;	270	my ($watcher, $revents) = @_;
135	warn "yeah, STDIN should not be readable without blocking!\n"	271	warn "yeah, STDIN should now be readable without blocking!\n"
136	};	272	};
137		273
138	All watchers can be active (waiting for events) or inactive (paused). Only	274	All watchers can be active (waiting for events) or inactive (paused). Only
139	active watchers will have their callbacks invoked. All callbacks will be	275	active watchers will have their callbacks invoked. All callbacks will be
140	called with at least two arguments: the watcher and a bitmask of received	276	called with at least two arguments: the watcher and a bitmask of received
141	events.	277	events.
142		278
143	Each watcher type has its associated bit in revents, so you can use the	279	Each watcher type has its associated bit in revents, so you can use the
144	same callback for multiple watchers. The event mask is named after the	280	same callback for multiple watchers. The event mask is named after the
145	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	281	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
146	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	282	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
147	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	283	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	284	uses EV::TIMEOUT).
149		285
150	In the rare case where one wants to create a watcher but not start it at	286	In the rare case where one wants to create a watcher but not start it at
151	the same time, each constructor has a variant with a trailing C<_ns> in	287	the same time, each constructor has a variant with a trailing C<_ns> in
152	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.	288	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
153		289
154	Please note that a watcher will automatically be stopped when the watcher	290	Please note that a watcher will automatically be stopped when the watcher
155	object is returned, so you I<need> to keep the watcher objects returned by	291	object is destroyed, so you I<need> to keep the watcher objects returned by
156	the constructors.	292	the constructors.
157		293
158	=head2 WATCHER TYPES	294	Also, all methods changing some aspect of a watcher (->set, ->priority,
		295	->fh and so on) automatically stop and start it again if it is active,
		296	which means pending events get lost.
159		297
160	Now lets move to the existing watcher types and asociated methods.	298	=head2 COMMON WATCHER METHODS
161		299
162	The following methods are available for all watchers. Then followes a	300	This section lists methods common to all watchers.
163	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
164	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
165	any type-specific methods (if any).
166		301
167	=over 4	302	=over 4
168		303
169	=item $w->start	304	=item $w->start
170		305
…		…
174		309
175	=item $w->stop	310	=item $w->stop
176		311
177	Stop a watcher if it is active. Also clear any pending events (events that	312	Stop a watcher if it is active. Also clear any pending events (events that
178	have been received but that didn't yet result in a callback invocation),	313	have been received but that didn't yet result in a callback invocation),
179	regardless of wether the watcher was active or not.	314	regardless of whether the watcher was active or not.
180		315
181	=item $bool = $w->is_active	316	=item $bool = $w->is_active
182		317
183	Returns true if the watcher is active, false otherwise.	318	Returns true if the watcher is active, false otherwise.
184		319
		320	=item $current_data = $w->data
		321
		322	=item $old_data = $w->data ($new_data)
		323
		324	Queries a freely usable data scalar on the watcher and optionally changes
		325	it. This is a way to associate custom data with a watcher:
		326
		327	my $w = EV::timer 60, 0, sub {
		328	warn $_[0]->data;
		329	};
		330	$w->data ("print me!");
		331
185	=item $current_cb = $w->cb	332	=item $current_cb = $w->cb
186		333
187	=item $old_cb = $w->cb ($new_cb)	334	=item $old_cb = $w->cb ($new_cb)
188		335
189	Queries the callback on the watcher and optionally changes it. You cna do	336	Queries the callback on the watcher and optionally changes it. You can do
190	this at any time.	337	this at any time without the watcher restarting.
191		338
		339	=item $current_priority = $w->priority
		340
		341	=item $old_priority = $w->priority ($new_priority)
		342
		343	Queries the priority on the watcher and optionally changes it. Pending
		344	watchers with higher priority will be invoked first. The valid range of
		345	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		346	-2). If the priority is outside this range it will automatically be
		347	normalised to the nearest valid priority.
		348
		349	The default priority of any newly-created watcher is 0.
		350
		351	Note that the priority semantics have not yet been fleshed out and are
		352	subject to almost certain change.
		353
192	=item $w->trigger ($revents)	354	=item $w->invoke ($revents)
193		355
194	Call the callback now with the given event mask.	356	Call the callback now with the given event mask.
195		357
		358	=item $w->feed_event ($revents)
		359
		360	Feed some events on this watcher into EV. EV will react to this call as if
		361	the watcher had received the given C<$revents> mask.
		362
		363	=item $revents = $w->clear_pending
		364
		365	If the watcher is pending, this function clears its pending status and
		366	returns its C<$revents> bitset (as if its callback was invoked). If the
		367	watcher isn't pending it does nothing and returns C<0>.
		368
		369	=item $previous_state = $w->keepalive ($bool)
		370
		371	Normally, C<EV::loop> will return when there are no active watchers
		372	(which is a "deadlock" because no progress can be made anymore). This is
		373	convinient because it allows you to start your watchers (and your jobs),
		374	call C<EV::loop> once and when it returns you know that all your jobs are
		375	finished (or they forgot to register some watchers for their task :).
		376
		377	Sometimes, however, this gets in your way, for example when the module
		378	that calls C<EV::loop> (usually the main program) is not the same module
		379	as a long-living watcher (for example a DNS client module written by
		380	somebody else even). Then you might want any outstanding requests to be
		381	handled, but you would not want to keep C<EV::loop> from returning just
		382	because you happen to have this long-running UDP port watcher.
		383
		384	In this case you can clear the keepalive status, which means that even
		385	though your watcher is active, it won't keep C<EV::loop> from returning.
		386
		387	The initial value for keepalive is true (enabled), and you cna change it
		388	any time.
		389
		390	Example: Register an I/O watcher for some UDP socket but do not keep the
		391	event loop from running just because of that watcher.
		392
		393	my $udp_socket = ...
		394	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		395	$1000udp_watcher->keepalive (0);
		396
		397	=item $loop = $w->loop
		398
		399	Return the loop that this watcher is attached to.
		400
		401	=back
		402
		403
		404	=head1 WATCHER TYPES
		405
		406	Each of the following subsections describes a single watcher type.
		407
		408	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		409
		410	=over 4
196		411
197	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	412	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
198		413
199	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	414	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
200		415
		416	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		417
		418	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		419
201	As long as the returned watcher object is alive, call the C<$callback>	420	As long as the returned watcher object is alive, call the C<$callback>
202	when the events specified in C<$eventmask>.	421	when at least one of events specified in C<$eventmask> occurs.
203		422
204	The $eventmask can be one or more of these constants ORed together:	423	The $eventmask can be one or more of these constants ORed together:
205		424
206	EV::READ wait until read() wouldn't block anymore	425	EV::READ wait until read() wouldn't block anymore
207	EV::WRITE wait until write() wouldn't block anymore	426	EV::WRITE wait until write() wouldn't block anymore
…		…
223		442
224	=item $old_eventmask = $w->events ($new_eventmask)	443	=item $old_eventmask = $w->events ($new_eventmask)
225		444
226	Returns the previously set event mask and optionally set a new one.	445	Returns the previously set event mask and optionally set a new one.
227		446
		447	=back
		448
		449
		450	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		451
		452	=over 4
228		453
229	=item $w = EV::timer $after, $repeat, $callback	454	=item $w = EV::timer $after, $repeat, $callback
230		455
231	=item $w = EV::timer_ns $after, $repeat, $callback	456	=item $w = EV::timer_ns $after, $repeat, $callback
232		457
233	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	458	=item $w = $loop->timer ($after, $repeat, $callback)
234	the timer will be restarted (with the $repeat value as $after) after the	459
235	callback returns.	460	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		461
		462	Calls the callback after C<$after> seconds (which may be fractional). If
		463	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		464	value as $after) after the callback returns.
236		465
237	This means that the callback would be called roughly after C<$after>	466	This means that the callback would be called roughly after C<$after>
238	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	467	seconds, and then every C<$repeat> seconds. The timer does his best not
239	callback processing is not taken into account, so the timer will slowly	468	to drift, but it will not invoke the timer more often then once per event
240	drift. If that isn't acceptable, look at EV::periodic.	469	loop iteration, and might drift in other cases. If that isn't acceptable,
		470	look at EV::periodic, which can provide long-term stable timers.
241		471
242	The timer is based on a monotonic clock, that is if somebody is sitting	472	The timer is based on a monotonic clock, that is, if somebody is sitting
243	in front of the machine while the timer is running and changes the system	473	in front of the machine while the timer is running and changes the system
244	clock, the timer will nevertheless run (roughly) the same time.	474	clock, the timer will nevertheless run (roughly) the same time.
245		475
246	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	476	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
247		477
248	=item $w->set ($after, $repeat)	478	=item $w->set ($after, $repeat)
249		479
250	Reconfigures the watcher, see the constructor above for details. Can be at	480	Reconfigures the watcher, see the constructor above for details. Can be called at
251	any time.	481	any time.
252		482
253	=item $w->again	483	=item $w->again
254		484
255	Similar to the C<start> method, but has special semantics for repeating timers:	485	Similar to the C<start> method, but has special semantics for repeating timers:
		486
		487	If the timer is active and non-repeating, it will be stopped.
256		488
257	If the timer is active and repeating, reset the timeout to occur	489	If the timer is active and repeating, reset the timeout to occur
258	C<$repeat> seconds after now.	490	C<$repeat> seconds after now.
259		491
260	If the timer is active and non-repeating, it will be stopped.
261
262	If the timer is in active and repeating, start it.	492	If the timer is inactive and repeating, start it using the repeat value.
263		493
264	Otherwise do nothing.	494	Otherwise do nothing.
265		495
266	This behaviour is useful when you have a timeout for some IO	496	This behaviour is useful when you have a timeout for some IO
267	operation. You create a timer object with the same value for C<$after> and	497	operation. You create a timer object with the same value for C<$after> and
268	C<$repeat>, and then, in the read/write watcher, run the C<again> method	498	C<$repeat>, and then, in the read/write watcher, run the C<again> method
269	on the timeout.	499	on the timeout.
270		500
		501	=back
271		502
		503
		504	=head3 PERIODIC WATCHERS - to cron or not to cron?
		505
		506	=over 4
		507
272	=item $w = EV::periodic $at, $interval, $callback	508	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
273		509
274	=item $w = EV::periodic_ns $at, $interval, $callback	510	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
275		511
276	Similar to EV::timer, but the time is given as an absolute point in time	512	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
277	(C<$at>), plus an optional C<$interval>.
278		513
279	If the C<$interval> is zero, then the callback will be called at the time	514	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
280	C<$at> if that is in the future, or as soon as possible if it is in the
281	past. It will not automatically repeat.
282		515
283	If the C<$interval> is nonzero, then the watcher will always be scheduled	516	Similar to EV::timer, but is not based on relative timeouts but on
284	to time out at the next C<$at + N * $interval> time.	517	absolute times. Apart from creating "simple" timers that trigger "at" the
		518	specified time, it can also be used for non-drifting absolute timers and
		519	more complex, cron-like, setups that are not adversely affected by time
		520	jumps (i.e. when the system clock is changed by explicit date -s or other
		521	means such as ntpd). It is also the most complex watcher type in EV.
285		522
286	This can be used to schedule a callback to run at very regular intervals,	523	It has three distinct "modes":
287	as long as the processing time is less then the interval (otherwise	524
288	obviously events will be skipped).	525	=over 4
		526
		527	=item * absolute timer ($interval = $reschedule_cb = 0)
		528
		529	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		530	will not adjust when a time jump occurs, that is, if it is to be run
		531	at January 1st 2011 then it will run when the system time reaches or
		532	surpasses this time.
		533
		534	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		535
		536	In this mode the watcher will always be scheduled to time out at the
		537	next C<$at + N * $interval> time (for some integer N) and then repeat,
		538	regardless of any time jumps.
		539
		540	This can be used to create timers that do not drift with respect to system
		541	time:
		542
		543	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		544
		545	That doesn't mean there will always be 3600 seconds in between triggers,
		546	but only that the the clalback will be called when the system time shows a
		547	full hour (UTC).
289		548
290	Another way to think about it (for the mathematically inclined) is that	549	Another way to think about it (for the mathematically inclined) is that
291	EV::periodic will try to run the callback at the next possible time where	550	EV::periodic will try to run the callback in this mode at the next
292	C<$time = $at (mod $interval)>, regardless of any time jumps.	551	possible time where C<$time = $at (mod $interval)>, regardless of any time
		552	jumps.
293		553
294	This periodic timer is based on "wallclock time", that is, if the clock	554	=item * manual reschedule mode ($reschedule_cb = coderef)
295	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	555
296	the specified time. This means it will never drift (it might jitter, but	556	In this mode $interval and $at are both being ignored. Instead, each
297	it will not drift).	557	time the periodic watcher gets scheduled, the reschedule callback
		558	($reschedule_cb) will be called with the watcher as first, and the current
		559	time as second argument.
		560
		561	I<This callback MUST NOT stop or destroy this or any other periodic
		562	watcher, ever>. If you need to stop it, return 1e30 and stop it
		563	afterwards.
		564
		565	It must return the next time to trigger, based on the passed time value
		566	(that is, the lowest time value larger than to the second argument). It
		567	will usually be called just before the callback will be triggered, but
		568	might be called at other times, too.
		569
		570	This can be used to create very complex timers, such as a timer that
		571	triggers on each midnight, local time (actually 24 hours after the last
		572	midnight, to keep the example simple. If you know a way to do it correctly
		573	in about the same space (without requiring elaborate modules), drop me a
		574	note :):
		575
		576	my $daily = EV::periodic 0, 0, sub {
		577	my ($w, $now) = @_;
		578
		579	use Time::Local ();
		580	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		581	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		582	}, sub {
		583	print "it's midnight or likely shortly after, now\n";
		584	};
		585
		586	=back
298		587
299	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	588	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
300		589
301	=item $w->set ($at, $interval)	590	=item $w->set ($at, $interval, $reschedule_cb)
302		591
303	Reconfigures the watcher, see the constructor above for details. Can be at	592	Reconfigures the watcher, see the constructor above for details. Can be called at
304	any time.	593	any time.
305		594
		595	=item $w->again
		596
		597	Simply stops and starts the watcher again.
		598
		599	=item $time = $w->at
		600
		601	Return the time that the watcher is expected to trigger next.
		602
		603	=back
		604
		605
		606	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		607
		608	=over 4
306		609
307	=item $w = EV::signal $signal, $callback	610	=item $w = EV::signal $signal, $callback
308		611
309	=item $w = EV::signal_ns $signal, $callback	612	=item $w = EV::signal_ns $signal, $callback
310		613
311	Call the callback when $signal is received (the signal can be specified	614	Call the callback when $signal is received (the signal can be specified by
312	by number or by name, just as with kill or %SIG).	615	number or by name, just as with C<kill> or C<%SIG>).
313		616
314	EV will grab the signal for the process (the kernel only allows one	617	EV will grab the signal for the process (the kernel only allows one
315	component to receive a signal at a time) when you start a signal watcher,	618	component to receive a signal at a time) when you start a signal watcher,
316	and removes it again when you stop it. Perl does the same when you	619	and removes it again when you stop it. Perl does the same when you
317	add/remove callbacks to %SIG, so watch out.	620	add/remove callbacks to C<%SIG>, so watch out.
318		621
319	You can have as many signal watchers per signal as you want.	622	You can have as many signal watchers per signal as you want.
320		623
321	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	624	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
322		625
323	=item $w->set ($signal)	626	=item $w->set ($signal)
324		627
325	Reconfigures the watcher, see the constructor above for details. Can be at	628	Reconfigures the watcher, see the constructor above for details. Can be
		629	called at any time.
		630
		631	=item $current_signum = $w->signal
		632
		633	=item $old_signum = $w->signal ($new_signal)
		634
		635	Returns the previously set signal (always as a number not name) and
		636	optionally set a new one.
		637
		638	=back
		639
		640
		641	=head3 CHILD WATCHERS - watch out for process status changes
		642
		643	=over 4
		644
		645	=item $w = EV::child $pid, $callback
		646
		647	=item $w = EV::child_ns $pid, $callback
		648
		649	=item $w = $loop->child ($pid, $callback)
		650
		651	=item $w = $loop->child_ns ($pid, $callback)
		652
		653	Call the callback when a status change for pid C<$pid> (or any pid if
		654	C<$pid> is 0) has been received. More precisely: when the process receives
		655	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
		656	changed/zombie children and call the callback.
		657
		658	It is valid (and fully supported) to install a child watcher after a child
		659	has exited but before the event loop has started its next iteration (for
		660	example, first you C<fork>, then the new child process might exit, and
		661	only then do you install a child watcher in the parent for the new pid).
		662
		663	You can access both exit (or tracing) status and pid by using the
		664	C<rstatus> and C<rpid> methods on the watcher object.
		665
		666	You can have as many pid watchers per pid as you want, they will all be
		667	called.
		668
		669	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		670
		671	=item $w->set ($pid)
		672
		673	Reconfigures the watcher, see the constructor above for details. Can be called at
326	any time.	674	any time.
327		675
		676	=item $current_pid = $w->pid
328		677
329	=item $w = EV::child $pid, $callback	678	=item $old_pid = $w->pid ($new_pid)
330		679
331	=item $w = EV::child_ns $pid, $callback	680	Returns the previously set process id and optionally set a new one.
332		681
333	Call the callback when a status change for pid C<$pid> (or any pid	682	=item $exit_status = $w->rstatus
334	if C<$pid> is 0) has been received. More precisely: when the process
335	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all
336	changed/zombie children and call the callback.
337		683
338	Unlike all other callbacks, this callback will be called with an	684	Return the exit/wait status (as returned by waitpid, see the waitpid entry
339	additional third argument which is the exit status. See the C<waitpid>	685	in perlfunc).
340	function for details.
341		686
342	You can have as many pid watchers per pid as you want.	687	=item $pid = $w->rpid
343		688
		689	Return the pid of the awaited child (useful when you have installed a
		690	watcher for all pids).
		691
		692	=back
		693
		694
		695	=head3 STAT WATCHERS - did the file attributes just change?
		696
		697	=over 4
		698
		699	=item $w = EV::stat $path, $interval, $callback
		700
		701	=item $w = EV::stat_ns $path, $interval, $callback
		702
		703	=item $w = $loop->stat ($path, $interval, $callback)
		704
		705	=item $w = $loop->stat_ns ($path, $interval, $callback)
		706
		707	Call the callback when a file status change has been detected on
		708	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		709	to "path does not exist" is a status change like any other.
		710
		711	The C<$interval> is a recommended polling interval for systems where
		712	OS-supported change notifications don't exist or are not supported. If
		713	you use C<0> then an unspecified default is used (which is highly
		714	recommended!), which is to be expected to be around five seconds usually.
		715
		716	This watcher type is not meant for massive numbers of stat watchers,
		717	as even with OS-supported change notifications, this can be
		718	resource-intensive.
		719
344	The C<child_ns> variant doesn't start (activate) the newly created watcher.	720	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
345		721
346	=item $w->set ($pid)	722	=item ... = $w->stat
347		723
		724	This call is very similar to the perl C<stat> built-in: It stats (using
		725	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		726	well as EV's idea of the current stat values) to the values found.
		727
		728	In scalar context, a boolean is return indicating success or failure of
		729	the stat. In list context, the same 13-value list as with stat is returned
		730	(except that the blksize and blocks fields are not reliable).
		731
		732	In the case of an error, errno is set to C<ENOENT> (regardless of the
		733	actual error value) and the C<nlink> value is forced to zero (if the stat
		734	was successful then nlink is guaranteed to be non-zero).
		735
		736	See also the next two entries for more info.
		737
		738	=item ... = $w->attr
		739
		740	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		741	the values most recently detected by EV. See the next entry for more info.
		742
		743	=item ... = $w->prev
		744
		745	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		746	the previous set of values, before the change.
		747
		748	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		749	to the values found I<before> a change was detected, while C<< $w->attr >>
		750	returns the values found leading to the change detection. The difference (if any)
		751	between C<prev> and C<attr> is what triggered the callback.
		752
		753	If you did something to the filesystem object and do not want to trigger
		754	yet another change, you can call C<stat> to update EV's idea of what the
		755	current attributes are.
		756
		757	=item $w->set ($path, $interval)
		758
348	Reconfigures the watcher, see the constructor above for details. Can be at	759	Reconfigures the watcher, see the constructor above for details. Can be
349	any time.	760	called at any time.
350		761
		762	=item $current_path = $w->path
		763
		764	=item $old_path = $w->path ($new_path)
		765
		766	Returns the previously set path and optionally set a new one.
		767
		768	=item $current_interval = $w->interval
		769
		770	=item $old_interval = $w->interval ($new_interval)
		771
		772	Returns the previously set interval and optionally set a new one. Can be
		773	used to query the actual interval used.
		774
		775	=back
		776
		777
		778	=head3 IDLE WATCHERS - when you've got nothing better to do...
		779
		780	=over 4
351		781
352	=item $w = EV::idle $callback	782	=item $w = EV::idle $callback
353		783
354	=item $w = EV::idle_ns $callback	784	=item $w = EV::idle_ns $callback
355		785
356	Call the callback when there are no pending io, timer/periodic, signal or	786	=item $w = $loop->idle ($callback)
357	child events, i.e. when the process is idle.	787
		788	=item $w = $loop->idle_ns ($callback)
		789
		790	Call the callback when there are no other pending watchers of the same or
		791	higher priority (excluding check, prepare and other idle watchers of the
		792	same or lower priority, of course). They are called idle watchers because
		793	when the watcher is the highest priority pending event in the process, the
		794	process is considered to be idle at that priority.
		795
		796	If you want a watcher that is only ever called when I<no> other events are
		797	outstanding you have to set the priority to C<EV::MINPRI>.
358		798
359	The process will not block as long as any idle watchers are active, and	799	The process will not block as long as any idle watchers are active, and
360	they will be called repeatedly until stopped.	800	they will be called repeatedly until stopped.
361		801
		802	For example, if you have idle watchers at priority C<0> and C<1>, and
		803	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		804	and the I/O watcher will always run when ready. Only when the idle watcher
		805	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		806	pending with the C<0>-priority idle watcher be invoked.
		807
362	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	808	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
363		809
		810	=back
		811
		812
		813	=head3 PREPARE WATCHERS - customise your event loop!
		814
		815	=over 4
364		816
365	=item $w = EV::prepare $callback	817	=item $w = EV::prepare $callback
366		818
367	=item $w = EV::prepare_ns $callback	819	=item $w = EV::prepare_ns $callback
		820
		821	=item $w = $loop->prepare ($callback)
		822
		823	=item $w = $loop->prepare_ns ($callback)
368		824
369	Call the callback just before the process would block. You can still	825	Call the callback just before the process would block. You can still
370	create/modify any watchers at this point.	826	create/modify any watchers at this point.
371		827
372	See the EV::check watcher, below, for explanations and an example.	828	See the EV::check watcher, below, for explanations and an example.
373		829
374	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	830	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
375		831
		832	=back
		833
		834
		835	=head3 CHECK WATCHERS - customise your event loop even more!
		836
		837	=over 4
376		838
377	=item $w = EV::check $callback	839	=item $w = EV::check $callback
378		840
379	=item $w = EV::check_ns $callback	841	=item $w = EV::check_ns $callback
		842
		843	=item $w = $loop->check ($callback)
		844
		845	=item $w = $loop->check_ns ($callback)
380		846
381	Call the callback just after the process wakes up again (after it has	847	Call the callback just after the process wakes up again (after it has
382	gathered events), but before any other callbacks have been invoked.	848	gathered events), but before any other callbacks have been invoked.
383		849
384	This is used to integrate other event-based software into the EV	850	This is used to integrate other event-based software into the EV
…		…
392	# do nothing unless active	858	# do nothing unless active
393	$dispatcher->{_event_queue_h}	859	$dispatcher->{_event_queue_h}
394	or return;	860	or return;
395		861
396	# make the dispatcher handle any outstanding stuff	862	# make the dispatcher handle any outstanding stuff
		863	... not shown
397		864
398	# create an IO watcher for each and every socket	865	# create an I/O watcher for each and every socket
399	@snmp_watcher = (	866	@snmp_watcher = (
400	(map { EV::io $_, EV::READ, sub { } }	867	(map { EV::io $_, EV::READ, sub { } }
401	keys %{ $dispatcher->{_descriptors} }),	868	keys %{ $dispatcher->{_descriptors} }),
		869
		870	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		871	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		872	0, sub { },
402	);	873	);
403
404	# if there are any timeouts, also create a timer
405	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
406	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
407	};	874	};
408		875
409	The callbacks are irrelevant, the only purpose of those watchers is	876	The callbacks are irrelevant (and are not even being called), the
410	to wake up the process as soon as one of those events occurs (socket	877	only purpose of those watchers is to wake up the process as soon as
411	readable, or timer timed out). The corresponding EV::check watcher will then	878	one of those events occurs (socket readable, or timer timed out). The
412	clean up:	879	corresponding EV::check watcher will then clean up:
413		880
414	our $snmp_check = EV::check sub {	881	our $snmp_check = EV::check sub {
415	# destroy all watchers	882	# destroy all watchers
416	@snmp_watcher = ();	883	@snmp_watcher = ();
417		884
418	# make the dispatcher handle any new stuff	885	# make the dispatcher handle any new stuff
		886	... not shown
419	};	887	};
420		888
421	The callbacks of the created watchers will not be called as the watchers	889	The callbacks of the created watchers will not be called as the watchers
422	are destroyed before this cna happen (remember EV::check gets called	890	are destroyed before this cna happen (remember EV::check gets called
423	first).	891	first).
424		892
425	The C<check_ns> variant doesn't start (activate) the newly created watcher.	893	The C<check_ns> variant doesn't start (activate) the newly created watcher.
426		894
427	=back	895	=back
428		896
		897
		898	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		899
		900	Fork watchers are called when a C<fork ()> was detected. The invocation
		901	is done before the event loop blocks next and before C<check> watchers
		902	are being called, and only in the child after the fork.
		903
		904	=over 4
		905
		906	=item $w = EV::fork $callback
		907
		908	=item $w = EV::fork_ns $callback
		909
		910	=item $w = $loop->fork ($callback)
		911
		912	=item $w = $loop->fork_ns ($callback)
		913
		914	Call the callback before the event loop is resumed in the child process
		915	after a fork.
		916
		917	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		918
		919	=back
		920
		921
		922	=head3 EMBED WATCHERS - when one backend isn't enough...
		923
		924	This is a rather advanced watcher type that lets you embed one event loop
		925	into another (currently only IO events are supported in the embedded
		926	loop, other types of watchers might be handled in a delayed or incorrect
		927	fashion and must not be used).
		928
		929	See the libev documentation at
		930	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		931	for more details.
		932
		933	In short, this watcher is most useful on BSD systems without working
		934	kqueue to still be able to handle a large number of sockets:
		935
		936	my $socket_loop;
		937
		938	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		939	if (
		940	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		941	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		942	) {
		943	# use kqueue for sockets
		944	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		945	}
		946
		947	# use the default loop otherwise
		948	$socket_loop \|\|= EV::default_loop;
		949
		950	=over 4
		951
		952	=item $w = EV::embed $otherloop, $callback
		953
		954	=item $w = EV::embed_ns $otherloop, $callback
		955
		956	=item $w = $loop->embed ($otherloop, $callback)
		957
		958	=item $w = $loop->embed_ns ($otherloop, $callback)
		959
		960	Call the callback when the embedded event loop (C<$otherloop>) has any
		961	I/O activity. The C<$callback> should alwas be specified as C<undef> in
		962	this version of EV, which means the embedded event loop will be managed
		963	automatically.
		964
		965	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		966
		967	=back
		968
		969
		970	=head1 PERL SIGNALS
		971
		972	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		973	with EV is as the same as any other C library: Perl-signals will only be
		974	handled when Perl runs, which means your signal handler might be invoked
		975	only the next time an event callback is invoked.
		976
		977	The solution is to use EV signal watchers (see C<EV::signal>), which will
		978	ensure proper operations with regards to other event watchers.
		979
		980	If you cannot do this for whatever reason, you can also force a watcher
		981	to be called on every event loop iteration by installing a C<EV::check>
		982	watcher:
		983
		984	my $async_check = EV::check sub { };
		985
		986	This ensures that perl gets into control for a short time to handle any
		987	pending signals, and also ensures (slightly) slower overall operation.
		988
429	=head1 THREADS	989	=head1 THREADS
430		990
431	Threads are not supported by this in any way. Perl pseudo-threads is evil	991	Threads are not supported by this module in any way. Perl pseudo-threads
432	stuff and must die.	992	is evil stuff and must die. As soon as Perl gains real threads I will work
		993	on thread support for it.
		994
		995	=head1 FORK
		996
		997	Most of the "improved" event delivering mechanisms of modern operating
		998	systems have quite a few problems with fork(2) (to put it bluntly: it is
		999	not supported and usually destructive). Libev makes it possible to work
		1000	around this by having a function that recreates the kernel state after
		1001	fork in the child.
		1002
		1003	On non-win32 platforms, this module requires the pthread_atfork
		1004	functionality to do this automatically for you. This function is quite
		1005	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1006	negligible, because everything the function currently does is set a flag
		1007	that is checked only when the event loop gets used the next time, so when
		1008	you do fork but not use EV, the overhead is minimal.
		1009
		1010	On win32, there is no notion of fork so all this doesn't apply, of course.
433		1011
434	=cut	1012	=cut
435		1013
436	our $DIED = sub {	1014	our $DIED = sub {
437	warn "EV: error in callback (ignoring): $@";	1015	warn "EV: error in callback (ignoring): $@";
438	};	1016	};
439		1017
440	init;	1018	default_loop
441		1019	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
442	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
443		1020
444	1;	1021	1;
445		1022
446	=head1 SEE ALSO	1023	=head1 SEE ALSO
447		1024
448	L<EV::DNS>, L<EV::AnyEvent>.	1025	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1026	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1027	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP).
449		1028
450	=head1 AUTHOR	1029	=head1 AUTHOR
451		1030
452	Marc Lehmann <schmorp@schmorp.de>	1031	Marc Lehmann <schmorp@schmorp.de>
453	http://home.schmorp.de/	1032	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs. Revision 1.79 by root, Sat Dec 22 16:37:07 2007 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs.
Revision 1.79 by root, Sat Dec 22 16:37:07 2007 UTC