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

Comparing EV/EV.pm (file contents):
Revision 1.37 by root, Mon Nov 12 07:58:52 2007 UTC vs.
Revision 1.96 by root, Thu May 22 02:44:57 2008 UTC

…		…
35	warn "sigquit received\n";	35	warn "sigquit received\n";
36	};	36	};
37		37
38	# CHILD/PID STATUS CHANGES	38	# CHILD/PID STATUS CHANGES
39		39
40	my $w = EV::child 666, sub {	40	my $w = EV::child 666, 0, sub {
41	my ($w, $revents) = @_;	41	my ($w, $revents) = @_;
42	my $status = $w->rstatus;	42	my $status = $w->rstatus;
43	};	43	};
		44
		45	# STAT CHANGES
		46	my $w = EV::stat "/etc/passwd", 10, sub {
		47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
		49	};
44		50
45	# MAINLOOP	51	# MAINLOOP
46	EV::loop; # loop until EV::loop_done is called or all watchers stop	52	EV::loop; # loop until EV::unloop is called or all watchers stop
47	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
48	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
49		55
50	=head1 DESCRIPTION	56	=head1 DESCRIPTION
51		57
52	This module provides an interface to libev	58	This module provides an interface to libev
53	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of libev
		61	itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more
		62	subtle details on watcher semantics or some discussion on the available
		63	backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just
		64	about in any case because it has much more detailed information.
		65
		66	This module is very fast and scalable. It is actually so fast that you
		67	can use it through the L<AnyEvent> module, stay portable to other event
		68	loops (if you don't rely on any watcher types not available through it)
		69	and still be faster than with any other event loop currently supported in
		70	Perl.
54		71
55	=cut	72	=cut
56		73
57	package EV;	74	package EV;
58		75
59	use strict;	76	use strict;
60		77
61	BEGIN {	78	BEGIN {
62	our $VERSION = '0.8';	79	our $VERSION = '3.41';
63	use XSLoader;	80	use XSLoader;
64	XSLoader::load "EV", $VERSION;	81	XSLoader::load "EV", $VERSION;
65	}	82	}
66		83
67	@EV::Io::ISA =	84	@EV::IO::ISA =
68	@EV::Timer::ISA =	85	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	86	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	87	@EV::Signal::ISA =
		88	@EV::Child::ISA =
		89	@EV::Stat::ISA =
71	@EV::Idle::ISA =	90	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	91	@EV::Prepare::ISA =
73	@EV::Check::ISA =	92	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	93	@EV::Embed::ISA =
		94	@EV::Fork::ISA =
		95	@EV::Async::ISA =
		96	"EV::Watcher";
		97
		98	@EV::Loop::Default::ISA = "EV::Loop";
		99
		100	=head1 EVENT LOOPS
		101
		102	EV supports multiple event loops: There is a single "default event loop"
		103	that can handle everything including signals and child watchers, and any
		104	number of "dynamic event loops" that can use different backends (with
		105	various limitations), but no child and signal watchers.
		106
		107	You do not have to do anything to create the default event loop: When
		108	the module is loaded a suitable backend is selected on the premise of
		109	selecting a working backend (which for example rules out kqueue on most
		110	BSDs). Modules should, unless they have "special needs" always use the
		111	default loop as this is fastest (perl-wise), best supported by other
		112	modules (e.g. AnyEvent or Coro) and most portable event loop.
		113
		114	For specific programs you can create additional event loops dynamically.
		115
		116	=over 4
		117
		118	=item $loop = new EV::loop [$flags]
		119
		120	Create a new event loop as per the specified flags. Please refer to the
		121	C<ev_loop_new ()> function description in the libev documentation
		122	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		123	for more info.
		124
		125	The loop will automatically be destroyed when it is no longer referenced
		126	by any watcher and the loop object goes out of scope.
		127
		128	Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
		129	is protected by this module.
		130
		131	=item $loop->loop_fork
		132
		133	Must be called after a fork in the child, before entering or continuing
		134	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		135	this function automatically, at some performance loss (refer to the libev
		136	documentation).
		137
		138	=item $loop->loop_verify
		139
		140	Calls C<ev_verify> to make internal consistency checks (for debugging
		141	libev) and abort the program if any data structures wree found to be
		142	corrupted.
		143
		144	=item $loop = EV::default_loop [$flags]
		145
		146	Return the default loop (which is a singleton object). Since this module
		147	already creates the default loop with default flags, specifying flags here
		148	will not have any effect unless you destroy the default loop.
		149
		150	=back
		151
75		152
76	=head1 BASIC INTERFACE	153	=head1 BASIC INTERFACE
77		154
78	=over 4	155	=over 4
79		156
80	=item $EV::DIED	157	=item $EV::DIED
81		158
82	Must contain a reference to a function that is called when a callback	159	Must contain a reference to a function that is called when a callback
83	throws an exception (with $@ containing thr error). The default prints an	160	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	161	informative message and continues.
85		162
86	If this callback throws an exception it will be silently ignored.	163	If this callback throws an exception it will be silently ignored.
87		164
		165	=item $flags = EV::supported_backends
		166
		167	=item $flags = EV::recommended_backends
		168
		169	=item $flags = EV::embeddable_backends
		170
		171	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		172	instance of EV, the set of recommended backends (supposed to be good) for
		173	this platform and the set of embeddable backends (see EMBED WATCHERS).
		174
		175	=item EV::sleep $seconds
		176
		177	Block the process for the given number of (fractional) seconds.
		178
88	=item $time = EV::time	179	=item $time = EV::time
89		180
90	Returns the current time in (fractional) seconds since the epoch.	181	Returns the current time in (fractional) seconds since the epoch.
91		182
92	=item $time = EV::now	183	=item $time = EV::now
		184
		185	=item $time = $loop->now
93		186
94	Returns the time the last event loop iteration has been started. This	187	Returns the time the last event loop iteration has been started. This
95	is the time that (relative) timers are based on, and refering to it is	188	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	189	usually faster then calling EV::time.
97		190
98	=item $method = EV::ev_method	191	=item $backend = EV::backend
		192
		193	=item $backend = $loop->backend
99		194
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	195	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	196	or EV::METHOD_EPOLL).
102		197
103	=item EV::loop [$flags]	198	=item EV::loop [$flags]
104		199
		200	=item $loop->loop ([$flags])
		201
105	Begin checking for events and calling callbacks. It returns when a	202	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::loop_done.	203	callback calls EV::unloop.
107		204
108	The $flags argument can be one of the following:	205	The $flags argument can be one of the following:
109		206
110	0 as above	207	0 as above
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	208	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	209	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		210
114	=item EV::loop_done [$how]	211	=item EV::unloop [$how]
115		212
		213	=item $loop->unloop ([$how])
		214
116	When called with no arguments or an argument of 1, makes the innermost	215	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	call to EV::loop return.	216	innermost call to EV::loop return.
118		217
119	When called with an agrument of 2, all calls to EV::loop will return as	218	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	219	fast as possible.
121		220
122	=back	221	=item $count = EV::loop_count
123		222
124	=head2 WATCHER	223	=item $count = $loop->loop_count
		224
		225	Return the number of times the event loop has polled for new
		226	events. Sometiems useful as a generation counter.
		227
		228	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		229
		230	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		231
		232	This function rolls together an I/O and a timer watcher for a single
		233	one-shot event without the need for managing a watcher object.
		234
		235	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		236	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		237	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		238	you do not want to wait for some I/O event, specify C<undef> for
		239	C<$fh_or_undef> and C<0> for C<$events>).
		240
		241	If timeout is C<undef> or negative, then there will be no
		242	timeout. Otherwise a EV::timer with this value will be started.
		243
		244	When an error occurs or either the timeout or I/O watcher triggers, then
		245	the callback will be called with the received event set (in general
		246	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		247	C<EV::WRITE> and C<EV::TIMEOUT>).
		248
		249	EV::once doesn't return anything: the watchers stay active till either
		250	of them triggers, then they will be stopped and freed, and the callback
		251	invoked.
		252
		253	=item EV::feed_fd_event ($fd, $revents)
		254
		255	=item $loop->feed_fd_event ($fd, $revents)
		256
		257	Feed an event on a file descriptor into EV. EV will react to this call as
		258	if the readyness notifications specified by C<$revents> (a combination of
		259	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		260
		261	=item EV::feed_signal_event ($signal)
		262
		263	Feed a signal event into EV. EV will react to this call as if the signal
		264	specified by C<$signal> had occured.
		265
		266	=item EV::set_io_collect_interval $time
		267
		268	=item $loop->set_io_collect_interval ($time)
		269
		270	=item EV::set_timeout_collect_interval $time
		271
		272	=item $loop->set_timeout_collect_interval ($time)
		273
		274	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		275	wait interval for timer events. See the libev documentation at
		276	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		277	a more detailed discussion.
		278
		279	=back
		280
		281
		282	=head1 WATCHER OBJECTS
125		283
126	A watcher is an object that gets created to record your interest in some	284	A watcher is an object that gets created to record your interest in some
127	event. For instance, if you want to wait for STDIN to become readable, you	285	event. For instance, if you want to wait for STDIN to become readable, you
128	would create an EV::io watcher for that:	286	would create an EV::io watcher for that:
129		287
130	my $watcher = EV::io *STDIN, EV::READ, sub {	288	my $watcher = EV::io *STDIN, EV::READ, sub {
131	my ($watcher, $revents) = @_;	289	my ($watcher, $revents) = @_;
132	warn "yeah, STDIN should not be readable without blocking!\n"	290	warn "yeah, STDIN should now be readable without blocking!\n"
133	};	291	};
134		292
135	All watchers can be active (waiting for events) or inactive (paused). Only	293	All watchers can be active (waiting for events) or inactive (paused). Only
136	active watchers will have their callbacks invoked. All callbacks will be	294	active watchers will have their callbacks invoked. All callbacks will be
137	called with at least two arguments: the watcher and a bitmask of received	295	called with at least two arguments: the watcher and a bitmask of received
138	events.	296	events.
139		297
140	Each watcher type has its associated bit in revents, so you can use the	298	Each watcher type has its associated bit in revents, so you can use the
141	same callback for multiple watchers. The event mask is named after the	299	same callback for multiple watchers. The event mask is named after the
142	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	300	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
143	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	301	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
144	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	302	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
145	uses EV::TIMEOUT).	303	uses EV::TIMEOUT).
146		304
147	In the rare case where one wants to create a watcher but not start it at	305	In the rare case where one wants to create a watcher but not start it at
148	the same time, each constructor has a variant with a trailing C<_ns> in	306	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
154		312
155	Also, all methods changing some aspect of a watcher (->set, ->priority,	313	Also, all methods changing some aspect of a watcher (->set, ->priority,
156	->fh and so on) automatically stop and start it again if it is active,	314	->fh and so on) automatically stop and start it again if it is active,
157	which means pending events get lost.	315	which means pending events get lost.
158		316
159	=head2 WATCHER TYPES	317	=head2 COMMON WATCHER METHODS
160		318
161	Now lets move to the existing watcher types and asociated methods.	319	This section lists methods common to all watchers.
162
163	The following methods are available for all watchers. Then followes a
164	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
165	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
166	any type-specific methods (if any).
167		320
168	=over 4	321	=over 4
169		322
170	=item $w->start	323	=item $w->start
171		324
…		…
175		328
176	=item $w->stop	329	=item $w->stop
177		330
178	Stop a watcher if it is active. Also clear any pending events (events that	331	Stop a watcher if it is active. Also clear any pending events (events that
179	have been received but that didn't yet result in a callback invocation),	332	have been received but that didn't yet result in a callback invocation),
180	regardless of wether the watcher was active or not.	333	regardless of whether the watcher was active or not.
181		334
182	=item $bool = $w->is_active	335	=item $bool = $w->is_active
183		336
184	Returns true if the watcher is active, false otherwise.	337	Returns true if the watcher is active, false otherwise.
185		338
…		…
210	watchers with higher priority will be invoked first. The valid range of	363	watchers with higher priority will be invoked first. The valid range of
211	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	364	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
212	-2). If the priority is outside this range it will automatically be	365	-2). If the priority is outside this range it will automatically be
213	normalised to the nearest valid priority.	366	normalised to the nearest valid priority.
214		367
215	The default priority of any newly-created weatcher is 0.	368	The default priority of any newly-created watcher is 0.
216		369
		370	Note that the priority semantics have not yet been fleshed out and are
		371	subject to almost certain change.
		372
217	=item $w->trigger ($revents)	373	=item $w->invoke ($revents)
218		374
219	Call the callback now with the given event mask.	375	Call the callback now with the given event mask.
220		376
		377	=item $w->feed_event ($revents)
		378
		379	Feed some events on this watcher into EV. EV will react to this call as if
		380	the watcher had received the given C<$revents> mask.
		381
		382	=item $revents = $w->clear_pending
		383
		384	If the watcher is pending, this function clears its pending status and
		385	returns its C<$revents> bitset (as if its callback was invoked). If the
		386	watcher isn't pending it does nothing and returns C<0>.
		387
		388	=item $previous_state = $w->keepalive ($bool)
		389
		390	Normally, C<EV::loop> will return when there are no active watchers
		391	(which is a "deadlock" because no progress can be made anymore). This is
		392	convinient because it allows you to start your watchers (and your jobs),
		393	call C<EV::loop> once and when it returns you know that all your jobs are
		394	finished (or they forgot to register some watchers for their task :).
		395
		396	Sometimes, however, this gets in your way, for example when the module
		397	that calls C<EV::loop> (usually the main program) is not the same module
		398	as a long-living watcher (for example a DNS client module written by
		399	somebody else even). Then you might want any outstanding requests to be
		400	handled, but you would not want to keep C<EV::loop> from returning just
		401	because you happen to have this long-running UDP port watcher.
		402
		403	In this case you can clear the keepalive status, which means that even
		404	though your watcher is active, it won't keep C<EV::loop> from returning.
		405
		406	The initial value for keepalive is true (enabled), and you cna change it
		407	any time.
		408
		409	Example: Register an I/O watcher for some UDP socket but do not keep the
		410	event loop from running just because of that watcher.
		411
		412	my $udp_socket = ...
		413	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		414	$1000udp_watcher->keepalive (0);
		415
		416	=item $loop = $w->loop
		417
		418	Return the loop that this watcher is attached to.
		419
		420	=back
		421
		422
		423	=head1 WATCHER TYPES
		424
		425	Each of the following subsections describes a single watcher type.
		426
		427	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		428
		429	=over 4
221		430
222	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	431	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
223		432
224	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	433	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
225		434
		435	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		436
		437	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		438
226	As long as the returned watcher object is alive, call the C<$callback>	439	As long as the returned watcher object is alive, call the C<$callback>
227	when the events specified in C<$eventmask>.	440	when at least one of events specified in C<$eventmask> occurs.
228		441
229	The $eventmask can be one or more of these constants ORed together:	442	The $eventmask can be one or more of these constants ORed together:
230		443
231	EV::READ wait until read() wouldn't block anymore	444	EV::READ wait until read() wouldn't block anymore
232	EV::WRITE wait until write() wouldn't block anymore	445	EV::WRITE wait until write() wouldn't block anymore
…		…
248		461
249	=item $old_eventmask = $w->events ($new_eventmask)	462	=item $old_eventmask = $w->events ($new_eventmask)
250		463
251	Returns the previously set event mask and optionally set a new one.	464	Returns the previously set event mask and optionally set a new one.
252		465
		466	=back
		467
		468
		469	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		470
		471	=over 4
253		472
254	=item $w = EV::timer $after, $repeat, $callback	473	=item $w = EV::timer $after, $repeat, $callback
255		474
256	=item $w = EV::timer_ns $after, $repeat, $callback	475	=item $w = EV::timer_ns $after, $repeat, $callback
257		476
258	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	477	=item $w = $loop->timer ($after, $repeat, $callback)
259	the timer will be restarted (with the $repeat value as $after) after the	478
260	callback returns.	479	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		480
		481	Calls the callback after C<$after> seconds (which may be fractional). If
		482	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		483	value as $after) after the callback returns.
261		484
262	This means that the callback would be called roughly after C<$after>	485	This means that the callback would be called roughly after C<$after>
263	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	486	seconds, and then every C<$repeat> seconds. The timer does his best not
264	callback processing is not taken into account, so the timer will slowly	487	to drift, but it will not invoke the timer more often then once per event
265	drift. If that isn't acceptable, look at EV::periodic.	488	loop iteration, and might drift in other cases. If that isn't acceptable,
		489	look at EV::periodic, which can provide long-term stable timers.
266		490
267	The timer is based on a monotonic clock, that is if somebody is sitting	491	The timer is based on a monotonic clock, that is, if somebody is sitting
268	in front of the machine while the timer is running and changes the system	492	in front of the machine while the timer is running and changes the system
269	clock, the timer will nevertheless run (roughly) the same time.	493	clock, the timer will nevertheless run (roughly) the same time.
270		494
271	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	495	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
272		496
273	=item $w->set ($after, $repeat)	497	=item $w->set ($after, $repeat)
274		498
275	Reconfigures the watcher, see the constructor above for details. Can be at	499	Reconfigures the watcher, see the constructor above for details. Can be called at
276	any time.	500	any time.
277		501
278	=item $w->again	502	=item $w->again
279		503
280	Similar to the C<start> method, but has special semantics for repeating timers:	504	Similar to the C<start> method, but has special semantics for repeating timers:
		505
		506	If the timer is active and non-repeating, it will be stopped.
281		507
282	If the timer is active and repeating, reset the timeout to occur	508	If the timer is active and repeating, reset the timeout to occur
283	C<$repeat> seconds after now.	509	C<$repeat> seconds after now.
284		510
285	If the timer is active and non-repeating, it will be stopped.
286
287	If the timer is in active and repeating, start it.	511	If the timer is inactive and repeating, start it using the repeat value.
288		512
289	Otherwise do nothing.	513	Otherwise do nothing.
290		514
291	This behaviour is useful when you have a timeout for some IO	515	This behaviour is useful when you have a timeout for some IO
292	operation. You create a timer object with the same value for C<$after> and	516	operation. You create a timer object with the same value for C<$after> and
293	C<$repeat>, and then, in the read/write watcher, run the C<again> method	517	C<$repeat>, and then, in the read/write watcher, run the C<again> method
294	on the timeout.	518	on the timeout.
295		519
		520	=back
		521
		522
		523	=head3 PERIODIC WATCHERS - to cron or not to cron?
		524
		525	=over 4
296		526
297	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	527	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
298		528
299	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	529	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		530
		531	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		532
		533	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
300		534
301	Similar to EV::timer, but is not based on relative timeouts but on	535	Similar to EV::timer, but is not based on relative timeouts but on
302	absolute times. Apart from creating "simple" timers that trigger "at" the	536	absolute times. Apart from creating "simple" timers that trigger "at" the
303	specified time, it can also be used for non-drifting absolute timers and	537	specified time, it can also be used for non-drifting absolute timers and
304	more complex, cron-like, setups that are not adversely affected by time	538	more complex, cron-like, setups that are not adversely affected by time
…		…
314	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	548	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
315	will not adjust when a time jump occurs, that is, if it is to be run	549	will not adjust when a time jump occurs, that is, if it is to be run
316	at January 1st 2011 then it will run when the system time reaches or	550	at January 1st 2011 then it will run when the system time reaches or
317	surpasses this time.	551	surpasses this time.
318		552
319	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	553	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
320		554
321	In this mode the watcher will always be scheduled to time out at the	555	In this mode the watcher will always be scheduled to time out at the
322	next C<$at + N * $interval> time (for some integer N) and then repeat,	556	next C<$at + N * $interval> time (for some integer N) and then repeat,
323	regardless of any time jumps.	557	regardless of any time jumps.
324		558
…		…
342	time the periodic watcher gets scheduled, the reschedule callback	576	time the periodic watcher gets scheduled, the reschedule callback
343	($reschedule_cb) will be called with the watcher as first, and the current	577	($reschedule_cb) will be called with the watcher as first, and the current
344	time as second argument.	578	time as second argument.
345		579
346	I<This callback MUST NOT stop or destroy this or any other periodic	580	I<This callback MUST NOT stop or destroy this or any other periodic
347	watcher, ever>. If you need to stop it, return 1e30 and stop it	581	watcher, ever, and MUST NOT call any event loop functions or methods>. If
348	afterwards.	582	you need to stop it, return 1e30 and stop it afterwards. You may create
		583	and start a C<EV::prepare> watcher for this task.
349		584
350	It must return the next time to trigger, based on the passed time value	585	It must return the next time to trigger, based on the passed time value
351	(that is, the lowest time value larger than to the second argument). It	586	(that is, the lowest time value larger than or equal to to the second
352	will usually be called just before the callback will be triggered, but	587	argument). It will usually be called just before the callback will be
353	might be called at other times, too.	588	triggered, but might be called at other times, too.
354		589
355	This can be used to create very complex timers, such as a timer that	590	This can be used to create very complex timers, such as a timer that
356	triggers on each midnight, local time (actually 24 hours after the last	591	triggers on each midnight, local time (actually 24 hours after the last
357	midnight, to keep the example simple. If you know a way to do it correctly	592	midnight, to keep the example simple. If you know a way to do it correctly
358	in about the same space (without requiring elaborate modules), drop me a	593	in about the same space (without requiring elaborate modules), drop me a
…		…
372		607
373	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	608	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
374		609
375	=item $w->set ($at, $interval, $reschedule_cb)	610	=item $w->set ($at, $interval, $reschedule_cb)
376		611
377	Reconfigures the watcher, see the constructor above for details. Can be at	612	Reconfigures the watcher, see the constructor above for details. Can be called at
378	any time.	613	any time.
379		614
380	=item $w->again	615	=item $w->again
381		616
382	Simply stops and starts the watcher again.	617	Simply stops and starts the watcher again.
383		618
		619	=item $time = $w->at
		620
		621	Return the time that the watcher is expected to trigger next.
		622
		623	=back
		624
		625
		626	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		627
		628	=over 4
384		629
385	=item $w = EV::signal $signal, $callback	630	=item $w = EV::signal $signal, $callback
386		631
387	=item $w = EV::signal_ns $signal, $callback	632	=item $w = EV::signal_ns $signal, $callback
388		633
389	Call the callback when $signal is received (the signal can be specified	634	Call the callback when $signal is received (the signal can be specified by
390	by number or by name, just as with kill or %SIG).	635	number or by name, just as with C<kill> or C<%SIG>).
391		636
392	EV will grab the signal for the process (the kernel only allows one	637	EV will grab the signal for the process (the kernel only allows one
393	component to receive a signal at a time) when you start a signal watcher,	638	component to receive a signal at a time) when you start a signal watcher,
394	and removes it again when you stop it. Perl does the same when you	639	and removes it again when you stop it. Perl does the same when you
395	add/remove callbacks to %SIG, so watch out.	640	add/remove callbacks to C<%SIG>, so watch out.
396		641
397	You can have as many signal watchers per signal as you want.	642	You can have as many signal watchers per signal as you want.
398		643
399	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	644	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
400		645
401	=item $w->set ($signal)	646	=item $w->set ($signal)
402		647
403	Reconfigures the watcher, see the constructor above for details. Can be at	648	Reconfigures the watcher, see the constructor above for details. Can be
404	any time.	649	called at any time.
405		650
406	=item $current_signum = $w->signal	651	=item $current_signum = $w->signal
407		652
408	=item $old_signum = $w->signal ($new_signal)	653	=item $old_signum = $w->signal ($new_signal)
409		654
410	Returns the previously set signal (always as a number not name) and	655	Returns the previously set signal (always as a number not name) and
411	optionally set a new one.	656	optionally set a new one.
412		657
		658	=back
413		659
		660
		661	=head3 CHILD WATCHERS - watch out for process status changes
		662
		663	=over 4
		664
414	=item $w = EV::child $pid, $callback	665	=item $w = EV::child $pid, $trace, $callback
415		666
416	=item $w = EV::child_ns $pid, $callback	667	=item $w = EV::child_ns $pid, $trace, $callback
		668
		669	=item $w = $loop->child ($pid, $trace, $callback)
		670
		671	=item $w = $loop->child_ns ($pid, $trace, $callback)
417		672
418	Call the callback when a status change for pid C<$pid> (or any pid	673	Call the callback when a status change for pid C<$pid> (or any pid
419	if C<$pid> is 0) has been received. More precisely: when the process	674	if C<$pid> is 0) has been received (a status change happens when the
		675	process terminates or is killed, or, when trace is true, additionally when
		676	it is stopped or continued). More precisely: when the process receives
420	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	677	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
421	changed/zombie children and call the callback.	678	changed/zombie children and call the callback.
422		679
423	You can access both status and pid by using the C<rstatus> and C<rpid>	680	It is valid (and fully supported) to install a child watcher after a child
424	methods on the watcher object.	681	has exited but before the event loop has started its next iteration (for
		682	example, first you C<fork>, then the new child process might exit, and
		683	only then do you install a child watcher in the parent for the new pid).
425		684
		685	You can access both exit (or tracing) status and pid by using the
		686	C<rstatus> and C<rpid> methods on the watcher object.
		687
426	You can have as many pid watchers per pid as you want.	688	You can have as many pid watchers per pid as you want, they will all be
		689	called.
427		690
428	The C<child_ns> variant doesn't start (activate) the newly created watcher.	691	The C<child_ns> variant doesn't start (activate) the newly created watcher.
429		692
430	=item $w->set ($pid)	693	=item $w->set ($pid, $trace)
431		694
432	Reconfigures the watcher, see the constructor above for details. Can be at	695	Reconfigures the watcher, see the constructor above for details. Can be called at
433	any time.	696	any time.
434		697
435	=item $current_pid = $w->pid	698	=item $current_pid = $w->pid
436
437	=item $old_pid = $w->pid ($new_pid)
438		699
439	Returns the previously set process id and optionally set a new one.	700	Returns the previously set process id and optionally set a new one.
440		701
441	=item $exit_status = $w->rstatus	702	=item $exit_status = $w->rstatus
442		703
…		…
446	=item $pid = $w->rpid	707	=item $pid = $w->rpid
447		708
448	Return the pid of the awaited child (useful when you have installed a	709	Return the pid of the awaited child (useful when you have installed a
449	watcher for all pids).	710	watcher for all pids).
450		711
		712	=back
		713
		714
		715	=head3 STAT WATCHERS - did the file attributes just change?
		716
		717	=over 4
		718
		719	=item $w = EV::stat $path, $interval, $callback
		720
		721	=item $w = EV::stat_ns $path, $interval, $callback
		722
		723	=item $w = $loop->stat ($path, $interval, $callback)
		724
		725	=item $w = $loop->stat_ns ($path, $interval, $callback)
		726
		727	Call the callback when a file status change has been detected on
		728	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		729	to "path does not exist" is a status change like any other.
		730
		731	The C<$interval> is a recommended polling interval for systems where
		732	OS-supported change notifications don't exist or are not supported. If
		733	you use C<0> then an unspecified default is used (which is highly
		734	recommended!), which is to be expected to be around five seconds usually.
		735
		736	This watcher type is not meant for massive numbers of stat watchers,
		737	as even with OS-supported change notifications, this can be
		738	resource-intensive.
		739
		740	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		741
		742	=item ... = $w->stat
		743
		744	This call is very similar to the perl C<stat> built-in: It stats (using
		745	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		746	well as EV's idea of the current stat values) to the values found.
		747
		748	In scalar context, a boolean is return indicating success or failure of
		749	the stat. In list context, the same 13-value list as with stat is returned
		750	(except that the blksize and blocks fields are not reliable).
		751
		752	In the case of an error, errno is set to C<ENOENT> (regardless of the
		753	actual error value) and the C<nlink> value is forced to zero (if the stat
		754	was successful then nlink is guaranteed to be non-zero).
		755
		756	See also the next two entries for more info.
		757
		758	=item ... = $w->attr
		759
		760	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		761	the values most recently detected by EV. See the next entry for more info.
		762
		763	=item ... = $w->prev
		764
		765	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		766	the previous set of values, before the change.
		767
		768	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		769	to the values found I<before> a change was detected, while C<< $w->attr >>
		770	returns the values found leading to the change detection. The difference (if any)
		771	between C<prev> and C<attr> is what triggered the callback.
		772
		773	If you did something to the filesystem object and do not want to trigger
		774	yet another change, you can call C<stat> to update EV's idea of what the
		775	current attributes are.
		776
		777	=item $w->set ($path, $interval)
		778
		779	Reconfigures the watcher, see the constructor above for details. Can be
		780	called at any time.
		781
		782	=item $current_path = $w->path
		783
		784	=item $old_path = $w->path ($new_path)
		785
		786	Returns the previously set path and optionally set a new one.
		787
		788	=item $current_interval = $w->interval
		789
		790	=item $old_interval = $w->interval ($new_interval)
		791
		792	Returns the previously set interval and optionally set a new one. Can be
		793	used to query the actual interval used.
		794
		795	=back
		796
		797
		798	=head3 IDLE WATCHERS - when you've got nothing better to do...
		799
		800	=over 4
451		801
452	=item $w = EV::idle $callback	802	=item $w = EV::idle $callback
453		803
454	=item $w = EV::idle_ns $callback	804	=item $w = EV::idle_ns $callback
455		805
456	Call the callback when there are no pending io, timer/periodic, signal or	806	=item $w = $loop->idle ($callback)
457	child events, i.e. when the process is idle.	807
		808	=item $w = $loop->idle_ns ($callback)
		809
		810	Call the callback when there are no other pending watchers of the same or
		811	higher priority (excluding check, prepare and other idle watchers of the
		812	same or lower priority, of course). They are called idle watchers because
		813	when the watcher is the highest priority pending event in the process, the
		814	process is considered to be idle at that priority.
		815
		816	If you want a watcher that is only ever called when I<no> other events are
		817	outstanding you have to set the priority to C<EV::MINPRI>.
458		818
459	The process will not block as long as any idle watchers are active, and	819	The process will not block as long as any idle watchers are active, and
460	they will be called repeatedly until stopped.	820	they will be called repeatedly until stopped.
461		821
		822	For example, if you have idle watchers at priority C<0> and C<1>, and
		823	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		824	and the I/O watcher will always run when ready. Only when the idle watcher
		825	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		826	pending with the C<0>-priority idle watcher be invoked.
		827
462	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	828	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
463		829
		830	=back
		831
		832
		833	=head3 PREPARE WATCHERS - customise your event loop!
		834
		835	=over 4
464		836
465	=item $w = EV::prepare $callback	837	=item $w = EV::prepare $callback
466		838
467	=item $w = EV::prepare_ns $callback	839	=item $w = EV::prepare_ns $callback
		840
		841	=item $w = $loop->prepare ($callback)
		842
		843	=item $w = $loop->prepare_ns ($callback)
468		844
469	Call the callback just before the process would block. You can still	845	Call the callback just before the process would block. You can still
470	create/modify any watchers at this point.	846	create/modify any watchers at this point.
471		847
472	See the EV::check watcher, below, for explanations and an example.	848	See the EV::check watcher, below, for explanations and an example.
473		849
474	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	850	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
475		851
		852	=back
		853
		854
		855	=head3 CHECK WATCHERS - customise your event loop even more!
		856
		857	=over 4
476		858
477	=item $w = EV::check $callback	859	=item $w = EV::check $callback
478		860
479	=item $w = EV::check_ns $callback	861	=item $w = EV::check_ns $callback
		862
		863	=item $w = $loop->check ($callback)
		864
		865	=item $w = $loop->check_ns ($callback)
480		866
481	Call the callback just after the process wakes up again (after it has	867	Call the callback just after the process wakes up again (after it has
482	gathered events), but before any other callbacks have been invoked.	868	gathered events), but before any other callbacks have been invoked.
483		869
484	This is used to integrate other event-based software into the EV	870	This is used to integrate other event-based software into the EV
…		…
492	# do nothing unless active	878	# do nothing unless active
493	$dispatcher->{_event_queue_h}	879	$dispatcher->{_event_queue_h}
494	or return;	880	or return;
495		881
496	# make the dispatcher handle any outstanding stuff	882	# make the dispatcher handle any outstanding stuff
		883	... not shown
497		884
498	# create an IO watcher for each and every socket	885	# create an I/O watcher for each and every socket
499	@snmp_watcher = (	886	@snmp_watcher = (
500	(map { EV::io $_, EV::READ, sub { } }	887	(map { EV::io $_, EV::READ, sub { } }
501	keys %{ $dispatcher->{_descriptors} }),	888	keys %{ $dispatcher->{_descriptors} }),
		889
		890	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		891	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		892	0, sub { },
502	);	893	);
503
504	# if there are any timeouts, also create a timer
505	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
506	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
507	};	894	};
508		895
509	The callbacks are irrelevant, the only purpose of those watchers is	896	The callbacks are irrelevant (and are not even being called), the
510	to wake up the process as soon as one of those events occurs (socket	897	only purpose of those watchers is to wake up the process as soon as
511	readable, or timer timed out). The corresponding EV::check watcher will then	898	one of those events occurs (socket readable, or timer timed out). The
512	clean up:	899	corresponding EV::check watcher will then clean up:
513		900
514	our $snmp_check = EV::check sub {	901	our $snmp_check = EV::check sub {
515	# destroy all watchers	902	# destroy all watchers
516	@snmp_watcher = ();	903	@snmp_watcher = ();
517		904
518	# make the dispatcher handle any new stuff	905	# make the dispatcher handle any new stuff
		906	... not shown
519	};	907	};
520		908
521	The callbacks of the created watchers will not be called as the watchers	909	The callbacks of the created watchers will not be called as the watchers
522	are destroyed before this cna happen (remember EV::check gets called	910	are destroyed before this cna happen (remember EV::check gets called
523	first).	911	first).
524		912
525	The C<check_ns> variant doesn't start (activate) the newly created watcher.	913	The C<check_ns> variant doesn't start (activate) the newly created watcher.
526		914
527	=back	915	=back
528		916
		917
		918	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		919
		920	Fork watchers are called when a C<fork ()> was detected. The invocation
		921	is done before the event loop blocks next and before C<check> watchers
		922	are being called, and only in the child after the fork.
		923
		924	=over 4
		925
		926	=item $w = EV::fork $callback
		927
		928	=item $w = EV::fork_ns $callback
		929
		930	=item $w = $loop->fork ($callback)
		931
		932	=item $w = $loop->fork_ns ($callback)
		933
		934	Call the callback before the event loop is resumed in the child process
		935	after a fork.
		936
		937	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		938
		939	=back
		940
		941
		942	=head3 EMBED WATCHERS - when one backend isn't enough...
		943
		944	This is a rather advanced watcher type that lets you embed one event loop
		945	into another (currently only IO events are supported in the embedded
		946	loop, other types of watchers might be handled in a delayed or incorrect
		947	fashion and must not be used).
		948
		949	See the libev documentation at
		950	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		951	for more details.
		952
		953	In short, this watcher is most useful on BSD systems without working
		954	kqueue to still be able to handle a large number of sockets:
		955
		956	my $socket_loop;
		957
		958	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		959	if (
		960	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		961	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		962	) {
		963	# use kqueue for sockets
		964	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		965	}
		966
		967	# use the default loop otherwise
		968	$socket_loop \|\|= EV::default_loop;
		969
		970	=over 4
		971
		972	=item $w = EV::embed $otherloop, $callback
		973
		974	=item $w = EV::embed_ns $otherloop, $callback
		975
		976	=item $w = $loop->embed ($otherloop, $callback)
		977
		978	=item $w = $loop->embed_ns ($otherloop, $callback)
		979
		980	Call the callback when the embedded event loop (C<$otherloop>) has any
		981	I/O activity. The C<$callback> should alwas be specified as C<undef> in
		982	this version of EV, which means the embedded event loop will be managed
		983	automatically.
		984
		985	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		986
		987	=back
		988
		989	=head3 ASYNC WATCHERS - how to wake up another event loop
		990
		991	Async watchers are provided by EV, but have little use in perl directly, as perl
		992	neither supports threads nor direct access to signal handlers or other
		993	contexts where they could be of value.
		994
		995	It is, however, possible to use them from the XS level.
		996
		997	Please see the libev documentation for further details.
		998
		999	=over 4
		1000
		1001	=item $w = EV::async $callback
		1002
		1003	=item $w = EV::async_ns $callback
		1004
		1005	=item $w->send
		1006
		1007	=item $bool = $w->async_pending
		1008
		1009	=back
		1010
		1011
		1012	=head1 PERL SIGNALS
		1013
		1014	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1015	with EV is as the same as any other C library: Perl-signals will only be
		1016	handled when Perl runs, which means your signal handler might be invoked
		1017	only the next time an event callback is invoked.
		1018
		1019	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1020	ensure proper operations with regards to other event watchers.
		1021
		1022	If you cannot do this for whatever reason, you can also force a watcher
		1023	to be called on every event loop iteration by installing a C<EV::check>
		1024	watcher:
		1025
		1026	my $async_check = EV::check sub { };
		1027
		1028	This ensures that perl gets into control for a short time to handle any
		1029	pending signals, and also ensures (slightly) slower overall operation.
		1030
529	=head1 THREADS	1031	=head1 THREADS
530		1032
531	Threads are not supported by this in any way. Perl pseudo-threads is evil	1033	Threads are not supported by this module in any way. Perl pseudo-threads
532	stuff and must die.	1034	is evil stuff and must die. As soon as Perl gains real threads I will work
		1035	on thread support for it.
		1036
		1037	=head1 FORK
		1038
		1039	Most of the "improved" event delivering mechanisms of modern operating
		1040	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1041	not supported and usually destructive). Libev makes it possible to work
		1042	around this by having a function that recreates the kernel state after
		1043	fork in the child.
		1044
		1045	On non-win32 platforms, this module requires the pthread_atfork
		1046	functionality to do this automatically for you. This function is quite
		1047	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1048	negligible, because everything the function currently does is set a flag
		1049	that is checked only when the event loop gets used the next time, so when
		1050	you do fork but not use EV, the overhead is minimal.
		1051
		1052	On win32, there is no notion of fork so all this doesn't apply, of course.
533		1053
534	=cut	1054	=cut
535		1055
536	our $DIED = sub {	1056	our $DIED = sub {
537	warn "EV: error in callback (ignoring): $@";	1057	warn "EV: error in callback (ignoring): $@";
538	};	1058	};
539		1059
540	default_loop	1060	default_loop
541	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1061	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
542		1062
543	1;	1063	1;
544		1064
545	=head1 SEE ALSO	1065	=head1 SEE ALSO
546		1066
547	L<EV::DNS>, L<EV::AnyEvent>.	1067	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1068	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1069	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1070	event-loop agnostic and portable event driven programming.
548		1071
549	=head1 AUTHOR	1072	=head1 AUTHOR
550		1073
551	Marc Lehmann <schmorp@schmorp.de>	1074	Marc Lehmann <schmorp@schmorp.de>
552	http://home.schmorp.de/	1075	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.37 by root, Mon Nov 12 07:58:52 2007 UTC vs. Revision 1.96 by root, Thu May 22 02:44:57 2008 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.37 by root, Mon Nov 12 07:58:52 2007 UTC vs.
Revision 1.96 by root, Thu May 22 02:44:57 2008 UTC