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

Comparing EV/EV.pm (file contents):
Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs.
Revision 1.77 by root, Sat Dec 22 11:44:50 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 cna 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	=back
		132
78		133
79	=head1 BASIC INTERFACE	134	=head1 BASIC INTERFACE
80		135
81	=over 4	136	=over 4
82		137
83	=item $EV::DIED	138	=item $EV::DIED
84		139
85	Must contain a reference to a function that is called when a callback	140	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	141	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	142	informative message and continues.
88		143
89	If this callback throws an exception it will be silently ignored.	144	If this callback throws an exception it will be silently ignored.
90		145
91	=item $time = EV::time	146	=item $time = EV::time
92		147
93	Returns the current time in (fractional) seconds since the epoch.	148	Returns the current time in (fractional) seconds since the epoch.
94		149
95	=item $time = EV::now	150	=item $time = EV::now
		151
		152	=item $time = $loop->now
96		153
97	Returns the time the last event loop iteration has been started. This	154	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	155	is the time that (relative) timers are based on, and refering to it is
99	usually faster then calling EV::time.	156	usually faster then calling EV::time.
100		157
101	=item $method = EV::ev_method	158	=item $backend = EV::backend
		159
		160	=item $backend = $loop->backend
102		161
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	162	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
104	or EV::METHOD_EPOLL).	163	or EV::METHOD_EPOLL).
105		164
106	=item EV::loop [$flags]	165	=item EV::loop [$flags]
107		166
		167	=item $loop->loop ([$flags])
		168
108	Begin checking for events and calling callbacks. It returns when a	169	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	170	callback calls EV::unloop.
110		171
111	The $flags argument can be one of the following:	172	The $flags argument can be one of the following:
112		173
113	0 as above	174	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	175	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	176	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		177
117	=item EV::loop_done [$how]	178	=item EV::unloop [$how]
118		179
		180	=item $loop->unloop ([$how])
		181
119	When called with no arguments or an argument of 1, makes the innermost	182	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	183	innermost call to EV::loop return.
121		184
122	When called with an agrument of 2, all calls to EV::loop will return as	185	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	186	fast as possible.
124		187
125	=back	188	=item $count = EV::loop_count
126		189
127	=head2 WATCHER	190	=item $count = $loop->loop_count
		191
		192	Return the number of times the event loop has polled for new
		193	events. Sometiems useful as a generation counter.
		194
		195	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		196
		197	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		198
		199	This function rolls together an I/O and a timer watcher for a single
		200	one-shot event without the need for managing a watcher object.
		201
		202	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		203	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		204	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		205	you do not want to wait for some I/O event, specify C<undef> for
		206	C<$fh_or_undef> and C<0> for C<$events>).
		207
		208	If timeout is C<undef> or negative, then there will be no
		209	timeout. Otherwise a EV::timer with this value will be started.
		210
		211	When an error occurs or either the timeout or I/O watcher triggers, then
		212	the callback will be called with the received event set (in general
		213	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		214	C<EV::WRITE> and C<EV::TIMEOUT>).
		215
		216	EV::once doesn't return anything: the watchers stay active till either
		217	of them triggers, then they will be stopped and freed, and the callback
		218	invoked.
		219
		220	=item EV::feed_fd_event ($fd, $revents)
		221
		222	=item $loop->feed_fd_event ($fd, $revents)
		223
		224	Feed an event on a file descriptor into EV. EV will react to this call as
		225	if the readyness notifications specified by C<$revents> (a combination of
		226	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		227
		228	=item EV::feed_signal_event ($signal)
		229
		230	Feed a signal event into EV. EV will react to this call as if the signal
		231	specified by C<$signal> had occured.
		232
		233	=back
		234
		235
		236	=head1 WATCHER OBJECTS
128		237
129	A watcher is an object that gets created to record your interest in some	238	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	239	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	240	would create an EV::io watcher for that:
132		241
133	my $watcher = EV::io *STDIN, EV::READ, sub {	242	my $watcher = EV::io *STDIN, EV::READ, sub {
134	my ($watcher, $revents) = @_;	243	my ($watcher, $revents) = @_;
135	warn "yeah, STDIN should not be readable without blocking!\n"	244	warn "yeah, STDIN should now be readable without blocking!\n"
136	};	245	};
137		246
138	All watchers can be active (waiting for events) or inactive (paused). Only	247	All watchers can be active (waiting for events) or inactive (paused). Only
139	active watchers will have their callbacks invoked. All callbacks will be	248	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	249	called with at least two arguments: the watcher and a bitmask of received
141	events.	250	events.
142		251
143	Each watcher type has its associated bit in revents, so you can use the	252	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	253	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,	254	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	255	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	256	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	257	uses EV::TIMEOUT).
149		258
150	In the rare case where one wants to create a watcher but not start it at	259	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	260	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
157		266
158	Also, all methods changing some aspect of a watcher (->set, ->priority,	267	Also, all methods changing some aspect of a watcher (->set, ->priority,
159	->fh and so on) automatically stop and start it again if it is active,	268	->fh and so on) automatically stop and start it again if it is active,
160	which means pending events get lost.	269	which means pending events get lost.
161		270
162	=head2 WATCHER TYPES	271	=head2 COMMON WATCHER METHODS
163		272
164	Now lets move to the existing watcher types and asociated methods.	273	This section lists methods common to all watchers.
165
166	The following methods are available for all watchers. Then followes a
167	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
168	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
169	any type-specific methods (if any).
170		274
171	=over 4	275	=over 4
172		276
173	=item $w->start	277	=item $w->start
174		278
…		…
178		282
179	=item $w->stop	283	=item $w->stop
180		284
181	Stop a watcher if it is active. Also clear any pending events (events that	285	Stop a watcher if it is active. Also clear any pending events (events that
182	have been received but that didn't yet result in a callback invocation),	286	have been received but that didn't yet result in a callback invocation),
183	regardless of wether the watcher was active or not.	287	regardless of whether the watcher was active or not.
184		288
185	=item $bool = $w->is_active	289	=item $bool = $w->is_active
186		290
187	Returns true if the watcher is active, false otherwise.	291	Returns true if the watcher is active, false otherwise.
		292
		293	=item $current_data = $w->data
		294
		295	=item $old_data = $w->data ($new_data)
		296
		297	Queries a freely usable data scalar on the watcher and optionally changes
		298	it. This is a way to associate custom data with a watcher:
		299
		300	my $w = EV::timer 60, 0, sub {
		301	warn $_[0]->data;
		302	};
		303	$w->data ("print me!");
188		304
189	=item $current_cb = $w->cb	305	=item $current_cb = $w->cb
190		306
191	=item $old_cb = $w->cb ($new_cb)	307	=item $old_cb = $w->cb ($new_cb)
192		308
…		…
201	watchers with higher priority will be invoked first. The valid range of	317	watchers with higher priority will be invoked first. The valid range of
202	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	318	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
203	-2). If the priority is outside this range it will automatically be	319	-2). If the priority is outside this range it will automatically be
204	normalised to the nearest valid priority.	320	normalised to the nearest valid priority.
205		321
206	The default priority of any newly-created weatcher is 0.	322	The default priority of any newly-created watcher is 0.
207		323
		324	Note that the priority semantics have not yet been fleshed out and are
		325	subject to almost certain change.
		326
208	=item $w->trigger ($revents)	327	=item $w->invoke ($revents)
209		328
210	Call the callback now with the given event mask.	329	Call the callback now with the given event mask.
211		330
		331	=item $w->feed_event ($revents)
		332
		333	Feed some events on this watcher into EV. EV will react to this call as if
		334	the watcher had received the given C<$revents> mask.
		335
		336	=item $revents = $w->clear_pending
		337
		338	If the watcher is pending, this function returns clears its pending status
		339	and returns its C<$revents> bitset (as if its callback was invoked). If the
		340	watcher isn't pending it does nothing and returns C<0>.
		341
		342	=item $previous_state = $w->keepalive ($bool)
		343
		344	Normally, C<EV::loop> will return when there are no active watchers
		345	(which is a "deadlock" because no progress can be made anymore). This is
		346	convinient because it allows you to start your watchers (and your jobs),
		347	call C<EV::loop> once and when it returns you know that all your jobs are
		348	finished (or they forgot to register some watchers for their task :).
		349
		350	Sometimes, however, this gets in your way, for example when the module
		351	that calls C<EV::loop> (usually the main program) is not the same module
		352	as a long-living watcher (for example a DNS client module written by
		353	somebody else even). Then you might want any outstanding requests to be
		354	handled, but you would not want to keep C<EV::loop> from returning just
		355	because you happen to have this long-running UDP port watcher.
		356
		357	In this case you can clear the keepalive status, which means that even
		358	though your watcher is active, it won't keep C<EV::loop> from returning.
		359
		360	The initial value for keepalive is true (enabled), and you cna change it
		361	any time.
		362
		363	Example: Register an I/O watcher for some UDP socket but do not keep the
		364	event loop from running just because of that watcher.
		365
		366	my $udp_socket = ...
		367	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		368	$1000udp_watcher->keepalive (0);
		369
		370	=item $loop = $w->loop
		371
		372	Return the loop that this watcher is attached to.
		373
		374	=back
		375
		376
		377	=head1 WATCHER TYPES
		378
		379	Each of the following subsections describes a single watcher type.
		380
		381	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		382
		383	=over 4
212		384
213	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	385	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
214		386
215	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	387	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
216		388
		389	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		390
		391	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		392
217	As long as the returned watcher object is alive, call the C<$callback>	393	As long as the returned watcher object is alive, call the C<$callback>
218	when the events specified in C<$eventmask>.	394	when at least one of events specified in C<$eventmask> occurs.
219		395
220	The $eventmask can be one or more of these constants ORed together:	396	The $eventmask can be one or more of these constants ORed together:
221		397
222	EV::READ wait until read() wouldn't block anymore	398	EV::READ wait until read() wouldn't block anymore
223	EV::WRITE wait until write() wouldn't block anymore	399	EV::WRITE wait until write() wouldn't block anymore
…		…
239		415
240	=item $old_eventmask = $w->events ($new_eventmask)	416	=item $old_eventmask = $w->events ($new_eventmask)
241		417
242	Returns the previously set event mask and optionally set a new one.	418	Returns the previously set event mask and optionally set a new one.
243		419
		420	=back
		421
		422
		423	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		424
		425	=over 4
244		426
245	=item $w = EV::timer $after, $repeat, $callback	427	=item $w = EV::timer $after, $repeat, $callback
246		428
247	=item $w = EV::timer_ns $after, $repeat, $callback	429	=item $w = EV::timer_ns $after, $repeat, $callback
248		430
249	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	431	=item $w = $loop->timer ($after, $repeat, $callback)
250	the timer will be restarted (with the $repeat value as $after) after the	432
251	callback returns.	433	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		434
		435	Calls the callback after C<$after> seconds (which may be fractional). If
		436	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		437	value as $after) after the callback returns.
252		438
253	This means that the callback would be called roughly after C<$after>	439	This means that the callback would be called roughly after C<$after>
254	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	440	seconds, and then every C<$repeat> seconds. The timer does his best not
255	callback processing is not taken into account, so the timer will slowly	441	to drift, but it will not invoke the timer more often then once per event
256	drift. If that isn't acceptable, look at EV::periodic.	442	loop iteration, and might drift in other cases. If that isn't acceptable,
		443	look at EV::periodic, which can provide long-term stable timers.
257		444
258	The timer is based on a monotonic clock, that is if somebody is sitting	445	The timer is based on a monotonic clock, that is, if somebody is sitting
259	in front of the machine while the timer is running and changes the system	446	in front of the machine while the timer is running and changes the system
260	clock, the timer will nevertheless run (roughly) the same time.	447	clock, the timer will nevertheless run (roughly) the same time.
261		448
262	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	449	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
263		450
264	=item $w->set ($after, $repeat)	451	=item $w->set ($after, $repeat)
265		452
266	Reconfigures the watcher, see the constructor above for details. Can be at	453	Reconfigures the watcher, see the constructor above for details. Can be called at
267	any time.	454	any time.
268		455
269	=item $w->again	456	=item $w->again
270		457
271	Similar to the C<start> method, but has special semantics for repeating timers:	458	Similar to the C<start> method, but has special semantics for repeating timers:
		459
		460	If the timer is active and non-repeating, it will be stopped.
272		461
273	If the timer is active and repeating, reset the timeout to occur	462	If the timer is active and repeating, reset the timeout to occur
274	C<$repeat> seconds after now.	463	C<$repeat> seconds after now.
275		464
276	If the timer is active and non-repeating, it will be stopped.
277
278	If the timer is in active and repeating, start it.	465	If the timer is inactive and repeating, start it using the repeat value.
279		466
280	Otherwise do nothing.	467	Otherwise do nothing.
281		468
282	This behaviour is useful when you have a timeout for some IO	469	This behaviour is useful when you have a timeout for some IO
283	operation. You create a timer object with the same value for C<$after> and	470	operation. You create a timer object with the same value for C<$after> and
284	C<$repeat>, and then, in the read/write watcher, run the C<again> method	471	C<$repeat>, and then, in the read/write watcher, run the C<again> method
285	on the timeout.	472	on the timeout.
286		473
		474	=back
287		475
		476
		477	=head3 PERIODIC WATCHERS - to cron or not to cron?
		478
		479	=over 4
		480
288	=item $w = EV::periodic $at, $interval, $callback	481	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
289		482
290	=item $w = EV::periodic_ns $at, $interval, $callback	483	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
291		484
292	Similar to EV::timer, but the time is given as an absolute point in time	485	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
293	(C<$at>), plus an optional C<$interval>.
294		486
295	If the C<$interval> is zero, then the callback will be called at the time	487	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
296	C<$at> if that is in the future, or as soon as possible if it is in the
297	past. It will not automatically repeat.
298		488
299	If the C<$interval> is nonzero, then the watcher will always be scheduled	489	Similar to EV::timer, but is not based on relative timeouts but on
300	to time out at the next C<$at + N * $interval> time.	490	absolute times. Apart from creating "simple" timers that trigger "at" the
		491	specified time, it can also be used for non-drifting absolute timers and
		492	more complex, cron-like, setups that are not adversely affected by time
		493	jumps (i.e. when the system clock is changed by explicit date -s or other
		494	means such as ntpd). It is also the most complex watcher type in EV.
301		495
302	This can be used to schedule a callback to run at very regular intervals,	496	It has three distinct "modes":
303	as long as the processing time is less then the interval (otherwise	497
304	obviously events will be skipped).	498	=over 4
		499
		500	=item * absolute timer ($interval = $reschedule_cb = 0)
		501
		502	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		503	will not adjust when a time jump occurs, that is, if it is to be run
		504	at January 1st 2011 then it will run when the system time reaches or
		505	surpasses this time.
		506
		507	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		508
		509	In this mode the watcher will always be scheduled to time out at the
		510	next C<$at + N * $interval> time (for some integer N) and then repeat,
		511	regardless of any time jumps.
		512
		513	This can be used to create timers that do not drift with respect to system
		514	time:
		515
		516	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		517
		518	That doesn't mean there will always be 3600 seconds in between triggers,
		519	but only that the the clalback will be called when the system time shows a
		520	full hour (UTC).
305		521
306	Another way to think about it (for the mathematically inclined) is that	522	Another way to think about it (for the mathematically inclined) is that
307	EV::periodic will try to run the callback at the next possible time where	523	EV::periodic will try to run the callback in this mode at the next
308	C<$time = $at (mod $interval)>, regardless of any time jumps.	524	possible time where C<$time = $at (mod $interval)>, regardless of any time
		525	jumps.
309		526
310	This periodic timer is based on "wallclock time", that is, if the clock	527	=item * manual reschedule mode ($reschedule_cb = coderef)
311	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	528
312	the specified time. This means it will never drift (it might jitter, but	529	In this mode $interval and $at are both being ignored. Instead, each
313	it will not drift).	530	time the periodic watcher gets scheduled, the reschedule callback
		531	($reschedule_cb) will be called with the watcher as first, and the current
		532	time as second argument.
		533
		534	I<This callback MUST NOT stop or destroy this or any other periodic
		535	watcher, ever>. If you need to stop it, return 1e30 and stop it
		536	afterwards.
		537
		538	It must return the next time to trigger, based on the passed time value
		539	(that is, the lowest time value larger than to the second argument). It
		540	will usually be called just before the callback will be triggered, but
		541	might be called at other times, too.
		542
		543	This can be used to create very complex timers, such as a timer that
		544	triggers on each midnight, local time (actually 24 hours after the last
		545	midnight, to keep the example simple. If you know a way to do it correctly
		546	in about the same space (without requiring elaborate modules), drop me a
		547	note :):
		548
		549	my $daily = EV::periodic 0, 0, sub {
		550	my ($w, $now) = @_;
		551
		552	use Time::Local ();
		553	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		554	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		555	}, sub {
		556	print "it's midnight or likely shortly after, now\n";
		557	};
		558
		559	=back
314		560
315	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	561	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
316		562
317	=item $w->set ($at, $interval)	563	=item $w->set ($at, $interval, $reschedule_cb)
318		564
319	Reconfigures the watcher, see the constructor above for details. Can be at	565	Reconfigures the watcher, see the constructor above for details. Can be called at
320	any time.	566	any time.
321		567
		568	=item $w->again
		569
		570	Simply stops and starts the watcher again.
		571
		572	=item $time = $w->at
		573
		574	Return the time that the watcher is expected to trigger next.
		575
		576	=back
		577
		578
		579	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		580
		581	=over 4
322		582
323	=item $w = EV::signal $signal, $callback	583	=item $w = EV::signal $signal, $callback
324		584
325	=item $w = EV::signal_ns $signal, $callback	585	=item $w = EV::signal_ns $signal, $callback
326		586
327	Call the callback when $signal is received (the signal can be specified	587	Call the callback when $signal is received (the signal can be specified by
328	by number or by name, just as with kill or %SIG).	588	number or by name, just as with C<kill> or C<%SIG>).
329		589
330	EV will grab the signal for the process (the kernel only allows one	590	EV will grab the signal for the process (the kernel only allows one
331	component to receive a signal at a time) when you start a signal watcher,	591	component to receive a signal at a time) when you start a signal watcher,
332	and removes it again when you stop it. Perl does the same when you	592	and removes it again when you stop it. Perl does the same when you
333	add/remove callbacks to %SIG, so watch out.	593	add/remove callbacks to C<%SIG>, so watch out.
334		594
335	You can have as many signal watchers per signal as you want.	595	You can have as many signal watchers per signal as you want.
336		596
337	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	597	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
338		598
339	=item $w->set ($signal)	599	=item $w->set ($signal)
340		600
341	Reconfigures the watcher, see the constructor above for details. Can be at	601	Reconfigures the watcher, see the constructor above for details. Can be
342	any time.	602	called at any time.
343		603
344	=item $current_signum = $w->signal	604	=item $current_signum = $w->signal
345		605
346	=item $old_signum = $w->signal ($new_signal)	606	=item $old_signum = $w->signal ($new_signal)
347		607
348	Returns the previously set signal (always as a number not name) and	608	Returns the previously set signal (always as a number not name) and
349	optionally set a new one.	609	optionally set a new one.
350		610
		611	=back
		612
		613
		614	=head3 CHILD WATCHERS - watch out for process status changes
		615
		616	=over 4
351		617
352	=item $w = EV::child $pid, $callback	618	=item $w = EV::child $pid, $callback
353		619
354	=item $w = EV::child_ns $pid, $callback	620	=item $w = EV::child_ns $pid, $callback
355		621
		622	=item $w = $loop->child ($pid, $callback)
		623
		624	=item $w = $loop->child_ns ($pid, $callback)
		625
356	Call the callback when a status change for pid C<$pid> (or any pid	626	Call the callback when a status change for pid C<$pid> (or any pid if
357	if C<$pid> is 0) has been received. More precisely: when the process	627	C<$pid> is 0) has been received. More precisely: when the process receives
358	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	628	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
359	changed/zombie children and call the callback.	629	changed/zombie children and call the callback.
360		630
361	Unlike all other callbacks, this callback will be called with an	631	It is valid (and fully supported) to install a child watcher after a child
362	additional third argument which is the exit status. See the C<waitpid>	632	has exited but before the event loop has started its next iteration (for
363	function for details.	633	example, first you C<fork>, then the new child process might exit, and
		634	only then do you install a child watcher in the parent for the new pid).
364		635
		636	You can access both exit (or tracing) status and pid by using the
		637	C<rstatus> and C<rpid> methods on the watcher object.
		638
365	You can have as many pid watchers per pid as you want.	639	You can have as many pid watchers per pid as you want, they will all be
		640	called.
366		641
367	The C<child_ns> variant doesn't start (activate) the newly created watcher.	642	The C<child_ns> variant doesn't start (activate) the newly created watcher.
368		643
369	=item $w->set ($pid)	644	=item $w->set ($pid)
370		645
371	Reconfigures the watcher, see the constructor above for details. Can be at	646	Reconfigures the watcher, see the constructor above for details. Can be called at
372	any time.	647	any time.
373		648
374	=item $current_pid = $w->pid	649	=item $current_pid = $w->pid
375		650
376	=item $old_pid = $w->pid ($new_pid)	651	=item $old_pid = $w->pid ($new_pid)
377		652
378	Returns the previously set process id and optionally set a new one.	653	Returns the previously set process id and optionally set a new one.
379		654
		655	=item $exit_status = $w->rstatus
		656
		657	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		658	in perlfunc).
		659
		660	=item $pid = $w->rpid
		661
		662	Return the pid of the awaited child (useful when you have installed a
		663	watcher for all pids).
		664
		665	=back
		666
		667
		668	=head3 STAT WATCHERS - did the file attributes just change?
		669
		670	=over 4
		671
		672	=item $w = EV::stat $path, $interval, $callback
		673
		674	=item $w = EV::stat_ns $path, $interval, $callback
		675
		676	=item $w = $loop->stat ($path, $interval, $callback)
		677
		678	=item $w = $loop->stat_ns ($path, $interval, $callback)
		679
		680	Call the callback when a file status change has been detected on
		681	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		682	to "path does not exist" is a status change like any other.
		683
		684	The C<$interval> is a recommended polling interval for systems where
		685	OS-supported change notifications don't exist or are not supported. If
		686	you use C<0> then an unspecified default is used (which is highly
		687	recommended!), which is to be expected to be around five seconds usually.
		688
		689	This watcher type is not meant for massive numbers of stat watchers,
		690	as even with OS-supported change notifications, this can be
		691	resource-intensive.
		692
		693	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		694
		695	=item ... = $w->stat
		696
		697	This call is very similar to the perl C<stat> built-in: It stats (using
		698	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		699	well as EV's idea of the current stat values) to the values found.
		700
		701	In scalar context, a boolean is return indicating success or failure of
		702	the stat. In list context, the same 13-value list as with stat is returned
		703	(except that the blksize and blocks fields are not reliable).
		704
		705	In the case of an error, errno is set to C<ENOENT> (regardless of the
		706	actual error value) and the C<nlink> value is forced to zero (if the stat
		707	was successful then nlink is guaranteed to be non-zero).
		708
		709	See also the next two entries for more info.
		710
		711	=item ... = $w->attr
		712
		713	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		714	the values most recently detected by EV. See the next entry for more info.
		715
		716	=item ... = $w->prev
		717
		718	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		719	the previous set of values, before the change.
		720
		721	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		722	to the values found I<before> a change was detected, while C<< $w->attr >>
		723	returns the values found leading to the change detection. The difference (if any)
		724	between C<prev> and C<attr> is what triggered the callback.
		725
		726	If you did something to the filesystem object and do not want to trigger
		727	yet another change, you can call C<stat> to update EV's idea of what the
		728	current attributes are.
		729
		730	=item $w->set ($path, $interval)
		731
		732	Reconfigures the watcher, see the constructor above for details. Can be
		733	called at any time.
		734
		735	=item $current_path = $w->path
		736
		737	=item $old_path = $w->path ($new_path)
		738
		739	Returns the previously set path and optionally set a new one.
		740
		741	=item $current_interval = $w->interval
		742
		743	=item $old_interval = $w->interval ($new_interval)
		744
		745	Returns the previously set interval and optionally set a new one. Can be
		746	used to query the actual interval used.
		747
		748	=back
		749
		750
		751	=head3 IDLE WATCHERS - when you've got nothing better to do...
		752
		753	=over 4
380		754
381	=item $w = EV::idle $callback	755	=item $w = EV::idle $callback
382		756
383	=item $w = EV::idle_ns $callback	757	=item $w = EV::idle_ns $callback
384		758
385	Call the callback when there are no pending io, timer/periodic, signal or	759	=item $w = $loop->idle ($callback)
386	child events, i.e. when the process is idle.	760
		761	=item $w = $loop->idle_ns ($callback)
		762
		763	Call the callback when there are no other pending watchers of the same or
		764	higher priority (excluding check, prepare and other idle watchers of the
		765	same or lower priority, of course). They are called idle watchers because
		766	when the watcher is the highest priority pending event in the process, the
		767	process is considered to be idle at that priority.
		768
		769	If you want a watcher that is only ever called when I<no> other events are
		770	outstanding you have to set the priority to C<EV::MINPRI>.
387		771
388	The process will not block as long as any idle watchers are active, and	772	The process will not block as long as any idle watchers are active, and
389	they will be called repeatedly until stopped.	773	they will be called repeatedly until stopped.
390		774
		775	For example, if you have idle watchers at priority C<0> and C<1>, and
		776	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		777	and the I/O watcher will always run when ready. Only when the idle watcher
		778	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		779	pending with the C<0>-priority idle watcher be invoked.
		780
391	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	781	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
392		782
		783	=back
		784
		785
		786	=head3 PREPARE WATCHERS - customise your event loop!
		787
		788	=over 4
393		789
394	=item $w = EV::prepare $callback	790	=item $w = EV::prepare $callback
395		791
396	=item $w = EV::prepare_ns $callback	792	=item $w = EV::prepare_ns $callback
		793
		794	=item $w = $loop->prepare ($callback)
		795
		796	=item $w = $loop->prepare_ns ($callback)
397		797
398	Call the callback just before the process would block. You can still	798	Call the callback just before the process would block. You can still
399	create/modify any watchers at this point.	799	create/modify any watchers at this point.
400		800
401	See the EV::check watcher, below, for explanations and an example.	801	See the EV::check watcher, below, for explanations and an example.
402		802
403	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	803	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
404		804
		805	=back
		806
		807
		808	=head3 CHECK WATCHERS - customise your event loop even more!
		809
		810	=over 4
405		811
406	=item $w = EV::check $callback	812	=item $w = EV::check $callback
407		813
408	=item $w = EV::check_ns $callback	814	=item $w = EV::check_ns $callback
		815
		816	=item $w = $loop->check ($callback)
		817
		818	=item $w = $loop->check_ns ($callback)
409		819
410	Call the callback just after the process wakes up again (after it has	820	Call the callback just after the process wakes up again (after it has
411	gathered events), but before any other callbacks have been invoked.	821	gathered events), but before any other callbacks have been invoked.
412		822
413	This is used to integrate other event-based software into the EV	823	This is used to integrate other event-based software into the EV
…		…
421	# do nothing unless active	831	# do nothing unless active
422	$dispatcher->{_event_queue_h}	832	$dispatcher->{_event_queue_h}
423	or return;	833	or return;
424		834
425	# make the dispatcher handle any outstanding stuff	835	# make the dispatcher handle any outstanding stuff
		836	... not shown
426		837
427	# create an IO watcher for each and every socket	838	# create an I/O watcher for each and every socket
428	@snmp_watcher = (	839	@snmp_watcher = (
429	(map { EV::io $_, EV::READ, sub { } }	840	(map { EV::io $_, EV::READ, sub { } }
430	keys %{ $dispatcher->{_descriptors} }),	841	keys %{ $dispatcher->{_descriptors} }),
		842
		843	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		844	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		845	0, sub { },
431	);	846	);
432
433	# if there are any timeouts, also create a timer
434	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
435	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
436	};	847	};
437		848
438	The callbacks are irrelevant, the only purpose of those watchers is	849	The callbacks are irrelevant (and are not even being called), the
439	to wake up the process as soon as one of those events occurs (socket	850	only purpose of those watchers is to wake up the process as soon as
440	readable, or timer timed out). The corresponding EV::check watcher will then	851	one of those events occurs (socket readable, or timer timed out). The
441	clean up:	852	corresponding EV::check watcher will then clean up:
442		853
443	our $snmp_check = EV::check sub {	854	our $snmp_check = EV::check sub {
444	# destroy all watchers	855	# destroy all watchers
445	@snmp_watcher = ();	856	@snmp_watcher = ();
446		857
447	# make the dispatcher handle any new stuff	858	# make the dispatcher handle any new stuff
		859	... not shown
448	};	860	};
449		861
450	The callbacks of the created watchers will not be called as the watchers	862	The callbacks of the created watchers will not be called as the watchers
451	are destroyed before this cna happen (remember EV::check gets called	863	are destroyed before this cna happen (remember EV::check gets called
452	first).	864	first).
453		865
454	The C<check_ns> variant doesn't start (activate) the newly created watcher.	866	The C<check_ns> variant doesn't start (activate) the newly created watcher.
455		867
456	=back	868	=back
457		869
		870
		871	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		872
		873	Fork watchers are called when a C<fork ()> was detected. The invocation
		874	is done before the event loop blocks next and before C<check> watchers
		875	are being called, and only in the child after the fork.
		876
		877	=over 4
		878
		879	=item $w = EV::fork $callback
		880
		881	=item $w = EV::fork_ns $callback
		882
		883	=item $w = $loop->fork ($callback)
		884
		885	=item $w = $loop->fork_ns ($callback)
		886
		887	Call the callback before the event loop is resumed in the child process
		888	after a fork.
		889
		890	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		891
		892	=back
		893
		894
		895	=head1 PERL SIGNALS
		896
		897	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		898	with EV is as the same as any other C library: Perl-signals will only be
		899	handled when Perl runs, which means your signal handler might be invoked
		900	only the next time an event callback is invoked.
		901
		902	The solution is to use EV signal watchers (see C<EV::signal>), which will
		903	ensure proper operations with regards to other event watchers.
		904
		905	If you cannot do this for whatever reason, you can also force a watcher
		906	to be called on every event loop iteration by installing a C<EV::check>
		907	watcher:
		908
		909	my $async_check = EV::check sub { };
		910
		911	This ensures that perl gets into control for a short time to handle any
		912	pending signals, and also ensures (slightly) slower overall operation.
		913
458	=head1 THREADS	914	=head1 THREADS
459		915
460	Threads are not supported by this in any way. Perl pseudo-threads is evil	916	Threads are not supported by this module in any way. Perl pseudo-threads
461	stuff and must die.	917	is evil stuff and must die. As soon as Perl gains real threads I will work
		918	on thread support for it.
		919
		920	=head1 FORK
		921
		922	Most of the "improved" event delivering mechanisms of modern operating
		923	systems have quite a few problems with fork(2) (to put it bluntly: it is
		924	not supported and usually destructive). Libev makes it possible to work
		925	around this by having a function that recreates the kernel state after
		926	fork in the child.
		927
		928	On non-win32 platforms, this module requires the pthread_atfork
		929	functionality to do this automatically for you. This function is quite
		930	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		931	negligible, because everything the function currently does is set a flag
		932	that is checked only when the event loop gets used the next time, so when
		933	you do fork but not use EV, the overhead is minimal.
		934
		935	On win32, there is no notion of fork so all this doesn't apply, of course.
462		936
463	=cut	937	=cut
464		938
465	our $DIED = sub {	939	our $DIED = sub {
466	warn "EV: error in callback (ignoring): $@";	940	warn "EV: error in callback (ignoring): $@";
467	};	941	};
468		942
469	init;	943	default_loop
470		944	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
471	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
472		945
473	1;	946	1;
474		947
475	=head1 SEE ALSO	948	=head1 SEE ALSO
476		949
477	L<EV::DNS>, L<EV::AnyEvent>.	950	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		951	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		952	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP).
478		953
479	=head1 AUTHOR	954	=head1 AUTHOR
480		955
481	Marc Lehmann <schmorp@schmorp.de>	956	Marc Lehmann <schmorp@schmorp.de>
482	http://home.schmorp.de/	957	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs. Revision 1.77 by root, Sat Dec 22 11:44:50 2007 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs.
Revision 1.77 by root, Sat Dec 22 11:44:50 2007 UTC