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

Comparing EV/EV.pm (file contents):
Revision 1.41 by root, Fri Nov 16 10:42:40 2007 UTC vs.
Revision 1.86 by root, Wed Apr 2 11:00:58 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	};
		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";
43	};	49	};
44		50
45	# MAINLOOP	51	# MAINLOOP
46	EV::loop; # loop until EV::unloop is called or all watchers stop	52	EV::loop; # loop until EV::unloop is called or all watchers stop
47	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
48	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
49		55
50	=head1 DESCRIPTION	56	=head1 DESCRIPTION
51		57
52	This module provides an interface to libev	58	This module provides an interface to libev
53	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of libev
		61	itself (L<http://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.
54		65
55	=cut	66	=cut
56		67
57	package EV;	68	package EV;
58		69
59	use strict;	70	use strict;
60		71
61	BEGIN {	72	BEGIN {
62	our $VERSION = '0.9';	73	our $VERSION = '3.2';
63	use XSLoader;	74	use XSLoader;
64	XSLoader::load "EV", $VERSION;	75	XSLoader::load "EV", $VERSION;
65	}	76	}
66		77
67	@EV::Io::ISA =	78	@EV::IO::ISA =
68	@EV::Timer::ISA =	79	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	80	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	81	@EV::Signal::ISA =
		82	@EV::Child::ISA =
		83	@EV::Stat::ISA =
71	@EV::Idle::ISA =	84	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	85	@EV::Prepare::ISA =
73	@EV::Check::ISA =	86	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	87	@EV::Embed::ISA =
		88	@EV::Fork::ISA =
		89	@EV::Async::ISA =
		90	"EV::Watcher";
		91
		92	@EV::Loop::Default::ISA = "EV::Loop";
		93
		94	=head1 EVENT LOOPS
		95
		96	EV supports multiple event loops: There is a single "default event loop"
		97	that can handle everything including signals and child watchers, and any
		98	number of "dynamic event loops" that can use different backends (with
		99	various limitations), but no child and signal watchers.
		100
		101	You do not have to do anything to create the default event loop: When
		102	the module is loaded a suitable backend is selected on the premise of
		103	selecting a working backend (which for example rules out kqueue on most
		104	BSDs). Modules should, unless they have "special needs" always use the
		105	default loop as this is fastest (perl-wise), best supported by other
		106	modules (e.g. AnyEvent or Coro) and most portable event loop.
		107
		108	For specific programs you can create additional event loops dynamically.
		109
		110	=over 4
		111
		112	=item $loop = new EV::loop [$flags]
		113
		114	Create a new event loop as per the specified flags. Please refer to the
		115	C<ev_loop_new ()> function description in the libev documentation
		116	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		117	for more info.
		118
		119	The loop will automatically be destroyed when it is no longer referenced
		120	by any watcher and the loop object goes out of scope.
		121
		122	Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
		123	is protected by this module.
		124
		125	=item $loop->loop_fork
		126
		127	Must be called after a fork in the child, before entering or continuing
		128	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		129	this fucntion automatically, at some performance loss (refer to the libev
		130	documentation).
		131
		132	=item $loop = EV::default_loop [$flags]
		133
		134	Return the default loop (which is a singleton object).
		135
		136	=back
		137
75		138
76	=head1 BASIC INTERFACE	139	=head1 BASIC INTERFACE
77		140
78	=over 4	141	=over 4
79		142
80	=item $EV::DIED	143	=item $EV::DIED
81		144
82	Must contain a reference to a function that is called when a callback	145	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	146	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	147	informative message and continues.
85		148
86	If this callback throws an exception it will be silently ignored.	149	If this callback throws an exception it will be silently ignored.
87		150
		151	=item $flags = EV::supported_backends
		152
		153	=item $flags = EV::recommended_backends
		154
		155	=item $flags = EV::embeddable_backends
		156
		157	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		158	instance of EV, the set of recommended backends (supposed to be good) for
		159	this platform and the set of embeddable backends (see EMBED WATCHERS).
		160
		161	=item EV::sleep $seconds
		162
		163	Block the process for the given number of (fractional) seconds.
		164
88	=item $time = EV::time	165	=item $time = EV::time
89		166
90	Returns the current time in (fractional) seconds since the epoch.	167	Returns the current time in (fractional) seconds since the epoch.
91		168
92	=item $time = EV::now	169	=item $time = EV::now
		170
		171	=item $time = $loop->now
93		172
94	Returns the time the last event loop iteration has been started. This	173	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	174	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	175	usually faster then calling EV::time.
97		176
98	=item $method = EV::method	177	=item $backend = EV::backend
		178
		179	=item $backend = $loop->backend
99		180
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	181	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	182	or EV::METHOD_EPOLL).
102		183
103	=item EV::loop [$flags]	184	=item EV::loop [$flags]
		185
		186	=item $loop->loop ([$flags])
104		187
105	Begin checking for events and calling callbacks. It returns when a	188	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	189	callback calls EV::unloop.
107		190
108	The $flags argument can be one of the following:	191	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	194	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	195	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		196
114	=item EV::unloop [$how]	197	=item EV::unloop [$how]
115		198
		199	=item $loop->unloop ([$how])
		200
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	201	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	202	innermost call to EV::loop return.
118		203
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	204	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	205	fast as possible.
121		206
122	=back	207	=item $count = EV::loop_count
123		208
124	=head2 WATCHER	209	=item $count = $loop->loop_count
		210
		211	Return the number of times the event loop has polled for new
		212	events. Sometiems useful as a generation counter.
		213
		214	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		215
		216	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		217
		218	This function rolls together an I/O and a timer watcher for a single
		219	one-shot event without the need for managing a watcher object.
		220
		221	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		222	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		223	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		224	you do not want to wait for some I/O event, specify C<undef> for
		225	C<$fh_or_undef> and C<0> for C<$events>).
		226
		227	If timeout is C<undef> or negative, then there will be no
		228	timeout. Otherwise a EV::timer with this value will be started.
		229
		230	When an error occurs or either the timeout or I/O watcher triggers, then
		231	the callback will be called with the received event set (in general
		232	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		233	C<EV::WRITE> and C<EV::TIMEOUT>).
		234
		235	EV::once doesn't return anything: the watchers stay active till either
		236	of them triggers, then they will be stopped and freed, and the callback
		237	invoked.
		238
		239	=item EV::feed_fd_event ($fd, $revents)
		240
		241	=item $loop->feed_fd_event ($fd, $revents)
		242
		243	Feed an event on a file descriptor into EV. EV will react to this call as
		244	if the readyness notifications specified by C<$revents> (a combination of
		245	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		246
		247	=item EV::feed_signal_event ($signal)
		248
		249	Feed a signal event into EV. EV will react to this call as if the signal
		250	specified by C<$signal> had occured.
		251
		252	=item EV::set_io_collect_interval $time
		253
		254	=item $loop->set_io_collect_interval ($time)
		255
		256	=item EV::set_timeout_collect_interval $time
		257
		258	=item $loop->set_timeout_collect_interval ($time)
		259
		260	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		261	wait interval for timer events. See the libev documentation at
		262	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		263	a more detailed discussion.
		264
		265	=back
		266
		267
		268	=head1 WATCHER OBJECTS
125		269
126	A watcher is an object that gets created to record your interest in some	270	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	271	event. For instance, if you want to wait for STDIN to become readable, you
128	would create an EV::io watcher for that:	272	would create an EV::io watcher for that:
129		273
130	my $watcher = EV::io *STDIN, EV::READ, sub {	274	my $watcher = EV::io *STDIN, EV::READ, sub {
131	my ($watcher, $revents) = @_;	275	my ($watcher, $revents) = @_;
132	warn "yeah, STDIN should not be readable without blocking!\n"	276	warn "yeah, STDIN should now be readable without blocking!\n"
133	};	277	};
134		278
135	All watchers can be active (waiting for events) or inactive (paused). Only	279	All watchers can be active (waiting for events) or inactive (paused). Only
136	active watchers will have their callbacks invoked. All callbacks will be	280	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	281	called with at least two arguments: the watcher and a bitmask of received
138	events.	282	events.
139		283
140	Each watcher type has its associated bit in revents, so you can use the	284	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	285	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,	286	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	287	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	288	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
145	uses EV::TIMEOUT).	289	uses EV::TIMEOUT).
146		290
147	In the rare case where one wants to create a watcher but not start it at	291	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	292	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
154		298
155	Also, all methods changing some aspect of a watcher (->set, ->priority,	299	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,	300	->fh and so on) automatically stop and start it again if it is active,
157	which means pending events get lost.	301	which means pending events get lost.
158		302
159	=head2 WATCHER TYPES	303	=head2 COMMON WATCHER METHODS
160		304
161	Now lets move to the existing watcher types and asociated methods.	305	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		306
168	=over 4	307	=over 4
169		308
170	=item $w->start	309	=item $w->start
171		310
…		…
175		314
176	=item $w->stop	315	=item $w->stop
177		316
178	Stop a watcher if it is active. Also clear any pending events (events that	317	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),	318	have been received but that didn't yet result in a callback invocation),
180	regardless of wether the watcher was active or not.	319	regardless of whether the watcher was active or not.
181		320
182	=item $bool = $w->is_active	321	=item $bool = $w->is_active
183		322
184	Returns true if the watcher is active, false otherwise.	323	Returns true if the watcher is active, false otherwise.
185		324
…		…
210	watchers with higher priority will be invoked first. The valid range of	349	watchers with higher priority will be invoked first. The valid range of
211	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	350	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
212	-2). If the priority is outside this range it will automatically be	351	-2). If the priority is outside this range it will automatically be
213	normalised to the nearest valid priority.	352	normalised to the nearest valid priority.
214		353
215	The default priority of any newly-created weatcher is 0.	354	The default priority of any newly-created watcher is 0.
216		355
		356	Note that the priority semantics have not yet been fleshed out and are
		357	subject to almost certain change.
		358
217	=item $w->trigger ($revents)	359	=item $w->invoke ($revents)
218		360
219	Call the callback now with the given event mask.	361	Call the callback now with the given event mask.
220		362
		363	=item $w->feed_event ($revents)
		364
		365	Feed some events on this watcher into EV. EV will react to this call as if
		366	the watcher had received the given C<$revents> mask.
		367
		368	=item $revents = $w->clear_pending
		369
		370	If the watcher is pending, this function clears its pending status and
		371	returns its C<$revents> bitset (as if its callback was invoked). If the
		372	watcher isn't pending it does nothing and returns C<0>.
		373
		374	=item $previous_state = $w->keepalive ($bool)
		375
		376	Normally, C<EV::loop> will return when there are no active watchers
		377	(which is a "deadlock" because no progress can be made anymore). This is
		378	convinient because it allows you to start your watchers (and your jobs),
		379	call C<EV::loop> once and when it returns you know that all your jobs are
		380	finished (or they forgot to register some watchers for their task :).
		381
		382	Sometimes, however, this gets in your way, for example when the module
		383	that calls C<EV::loop> (usually the main program) is not the same module
		384	as a long-living watcher (for example a DNS client module written by
		385	somebody else even). Then you might want any outstanding requests to be
		386	handled, but you would not want to keep C<EV::loop> from returning just
		387	because you happen to have this long-running UDP port watcher.
		388
		389	In this case you can clear the keepalive status, which means that even
		390	though your watcher is active, it won't keep C<EV::loop> from returning.
		391
		392	The initial value for keepalive is true (enabled), and you cna change it
		393	any time.
		394
		395	Example: Register an I/O watcher for some UDP socket but do not keep the
		396	event loop from running just because of that watcher.
		397
		398	my $udp_socket = ...
		399	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		400	$1000udp_watcher->keepalive (0);
		401
		402	=item $loop = $w->loop
		403
		404	Return the loop that this watcher is attached to.
		405
		406	=back
		407
		408
		409	=head1 WATCHER TYPES
		410
		411	Each of the following subsections describes a single watcher type.
		412
		413	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		414
		415	=over 4
221		416
222	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	417	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
223		418
224	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	419	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
225		420
		421	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		422
		423	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		424
226	As long as the returned watcher object is alive, call the C<$callback>	425	As long as the returned watcher object is alive, call the C<$callback>
227	when the events specified in C<$eventmask>.	426	when at least one of events specified in C<$eventmask> occurs.
228		427
229	The $eventmask can be one or more of these constants ORed together:	428	The $eventmask can be one or more of these constants ORed together:
230		429
231	EV::READ wait until read() wouldn't block anymore	430	EV::READ wait until read() wouldn't block anymore
232	EV::WRITE wait until write() wouldn't block anymore	431	EV::WRITE wait until write() wouldn't block anymore
…		…
248		447
249	=item $old_eventmask = $w->events ($new_eventmask)	448	=item $old_eventmask = $w->events ($new_eventmask)
250		449
251	Returns the previously set event mask and optionally set a new one.	450	Returns the previously set event mask and optionally set a new one.
252		451
		452	=back
		453
		454
		455	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		456
		457	=over 4
253		458
254	=item $w = EV::timer $after, $repeat, $callback	459	=item $w = EV::timer $after, $repeat, $callback
255		460
256	=item $w = EV::timer_ns $after, $repeat, $callback	461	=item $w = EV::timer_ns $after, $repeat, $callback
257		462
258	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	463	=item $w = $loop->timer ($after, $repeat, $callback)
259	the timer will be restarted (with the $repeat value as $after) after the	464
260	callback returns.	465	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		466
		467	Calls the callback after C<$after> seconds (which may be fractional). If
		468	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		469	value as $after) after the callback returns.
261		470
262	This means that the callback would be called roughly after C<$after>	471	This means that the callback would be called roughly after C<$after>
263	seconds, and then every C<$repeat> seconds. The timer does his best not	472	seconds, and then every C<$repeat> seconds. The timer does his best not
264	to drift, but it will not invoke the timer more often then once per event	473	to drift, but it will not invoke the timer more often then once per event
265	loop iteration, and might drift in other cases. If that isn't acceptable,	474	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
271		480
272	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	481	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
273		482
274	=item $w->set ($after, $repeat)	483	=item $w->set ($after, $repeat)
275		484
276	Reconfigures the watcher, see the constructor above for details. Can be at	485	Reconfigures the watcher, see the constructor above for details. Can be called at
277	any time.	486	any time.
278		487
279	=item $w->again	488	=item $w->again
280		489
281	Similar to the C<start> method, but has special semantics for repeating timers:	490	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
292	This behaviour is useful when you have a timeout for some IO	501	This behaviour is useful when you have a timeout for some IO
293	operation. You create a timer object with the same value for C<$after> and	502	operation. You create a timer object with the same value for C<$after> and
294	C<$repeat>, and then, in the read/write watcher, run the C<again> method	503	C<$repeat>, and then, in the read/write watcher, run the C<again> method
295	on the timeout.	504	on the timeout.
296		505
		506	=back
		507
		508
		509	=head3 PERIODIC WATCHERS - to cron or not to cron?
		510
		511	=over 4
297		512
298	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	513	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
299		514
300	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	515	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		516
		517	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		518
		519	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
301		520
302	Similar to EV::timer, but is not based on relative timeouts but on	521	Similar to EV::timer, but is not based on relative timeouts but on
303	absolute times. Apart from creating "simple" timers that trigger "at" the	522	absolute times. Apart from creating "simple" timers that trigger "at" the
304	specified time, it can also be used for non-drifting absolute timers and	523	specified time, it can also be used for non-drifting absolute timers and
305	more complex, cron-like, setups that are not adversely affected by time	524	more complex, cron-like, setups that are not adversely affected by time
…		…
315	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	534	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
316	will not adjust when a time jump occurs, that is, if it is to be run	535	will not adjust when a time jump occurs, that is, if it is to be run
317	at January 1st 2011 then it will run when the system time reaches or	536	at January 1st 2011 then it will run when the system time reaches or
318	surpasses this time.	537	surpasses this time.
319		538
320	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	539	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
321		540
322	In this mode the watcher will always be scheduled to time out at the	541	In this mode the watcher will always be scheduled to time out at the
323	next C<$at + N * $interval> time (for some integer N) and then repeat,	542	next C<$at + N * $interval> time (for some integer N) and then repeat,
324	regardless of any time jumps.	543	regardless of any time jumps.
325		544
…		…
373		592
374	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	593	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
375		594
376	=item $w->set ($at, $interval, $reschedule_cb)	595	=item $w->set ($at, $interval, $reschedule_cb)
377		596
378	Reconfigures the watcher, see the constructor above for details. Can be at	597	Reconfigures the watcher, see the constructor above for details. Can be called at
379	any time.	598	any time.
380		599
381	=item $w->again	600	=item $w->again
382		601
383	Simply stops and starts the watcher again.	602	Simply stops and starts the watcher again.
384		603
		604	=item $time = $w->at
		605
		606	Return the time that the watcher is expected to trigger next.
		607
		608	=back
		609
		610
		611	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		612
		613	=over 4
385		614
386	=item $w = EV::signal $signal, $callback	615	=item $w = EV::signal $signal, $callback
387		616
388	=item $w = EV::signal_ns $signal, $callback	617	=item $w = EV::signal_ns $signal, $callback
389		618
390	Call the callback when $signal is received (the signal can be specified	619	Call the callback when $signal is received (the signal can be specified by
391	by number or by name, just as with kill or %SIG).	620	number or by name, just as with C<kill> or C<%SIG>).
392		621
393	EV will grab the signal for the process (the kernel only allows one	622	EV will grab the signal for the process (the kernel only allows one
394	component to receive a signal at a time) when you start a signal watcher,	623	component to receive a signal at a time) when you start a signal watcher,
395	and removes it again when you stop it. Perl does the same when you	624	and removes it again when you stop it. Perl does the same when you
396	add/remove callbacks to %SIG, so watch out.	625	add/remove callbacks to C<%SIG>, so watch out.
397		626
398	You can have as many signal watchers per signal as you want.	627	You can have as many signal watchers per signal as you want.
399		628
400	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	629	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
401		630
402	=item $w->set ($signal)	631	=item $w->set ($signal)
403		632
404	Reconfigures the watcher, see the constructor above for details. Can be at	633	Reconfigures the watcher, see the constructor above for details. Can be
405	any time.	634	called at any time.
406		635
407	=item $current_signum = $w->signal	636	=item $current_signum = $w->signal
408		637
409	=item $old_signum = $w->signal ($new_signal)	638	=item $old_signum = $w->signal ($new_signal)
410		639
411	Returns the previously set signal (always as a number not name) and	640	Returns the previously set signal (always as a number not name) and
412	optionally set a new one.	641	optionally set a new one.
413		642
		643	=back
414		644
		645
		646	=head3 CHILD WATCHERS - watch out for process status changes
		647
		648	=over 4
		649
415	=item $w = EV::child $pid, $callback	650	=item $w = EV::child $pid, $trace, $callback
416		651
417	=item $w = EV::child_ns $pid, $callback	652	=item $w = EV::child_ns $pid, $trace, $callback
		653
		654	=item $w = $loop->child ($pid, $trace, $callback)
		655
		656	=item $w = $loop->child_ns ($pid, $trace, $callback)
418		657
419	Call the callback when a status change for pid C<$pid> (or any pid	658	Call the callback when a status change for pid C<$pid> (or any pid
420	if C<$pid> is 0) has been received. More precisely: when the process	659	if C<$pid> is 0) has been received (a status change happens when the
		660	process terminates or is killed, or, when trace is true, additionally when
		661	it is stopped or continued). More precisely: when the process receives
421	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	662	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
422	changed/zombie children and call the callback.	663	changed/zombie children and call the callback.
423		664
424	You can access both status and pid by using the C<rstatus> and C<rpid>	665	It is valid (and fully supported) to install a child watcher after a child
425	methods on the watcher object.	666	has exited but before the event loop has started its next iteration (for
		667	example, first you C<fork>, then the new child process might exit, and
		668	only then do you install a child watcher in the parent for the new pid).
426		669
		670	You can access both exit (or tracing) status and pid by using the
		671	C<rstatus> and C<rpid> methods on the watcher object.
		672
427	You can have as many pid watchers per pid as you want.	673	You can have as many pid watchers per pid as you want, they will all be
		674	called.
428		675
429	The C<child_ns> variant doesn't start (activate) the newly created watcher.	676	The C<child_ns> variant doesn't start (activate) the newly created watcher.
430		677
431	=item $w->set ($pid)	678	=item $w->set ($pid, $trace)
432		679
433	Reconfigures the watcher, see the constructor above for details. Can be at	680	Reconfigures the watcher, see the constructor above for details. Can be called at
434	any time.	681	any time.
435		682
436	=item $current_pid = $w->pid	683	=item $current_pid = $w->pid
437
438	=item $old_pid = $w->pid ($new_pid)
439		684
440	Returns the previously set process id and optionally set a new one.	685	Returns the previously set process id and optionally set a new one.
441		686
442	=item $exit_status = $w->rstatus	687	=item $exit_status = $w->rstatus
443		688
…		…
447	=item $pid = $w->rpid	692	=item $pid = $w->rpid
448		693
449	Return the pid of the awaited child (useful when you have installed a	694	Return the pid of the awaited child (useful when you have installed a
450	watcher for all pids).	695	watcher for all pids).
451		696
		697	=back
		698
		699
		700	=head3 STAT WATCHERS - did the file attributes just change?
		701
		702	=over 4
		703
		704	=item $w = EV::stat $path, $interval, $callback
		705
		706	=item $w = EV::stat_ns $path, $interval, $callback
		707
		708	=item $w = $loop->stat ($path, $interval, $callback)
		709
		710	=item $w = $loop->stat_ns ($path, $interval, $callback)
		711
		712	Call the callback when a file status change has been detected on
		713	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		714	to "path does not exist" is a status change like any other.
		715
		716	The C<$interval> is a recommended polling interval for systems where
		717	OS-supported change notifications don't exist or are not supported. If
		718	you use C<0> then an unspecified default is used (which is highly
		719	recommended!), which is to be expected to be around five seconds usually.
		720
		721	This watcher type is not meant for massive numbers of stat watchers,
		722	as even with OS-supported change notifications, this can be
		723	resource-intensive.
		724
		725	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		726
		727	=item ... = $w->stat
		728
		729	This call is very similar to the perl C<stat> built-in: It stats (using
		730	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		731	well as EV's idea of the current stat values) to the values found.
		732
		733	In scalar context, a boolean is return indicating success or failure of
		734	the stat. In list context, the same 13-value list as with stat is returned
		735	(except that the blksize and blocks fields are not reliable).
		736
		737	In the case of an error, errno is set to C<ENOENT> (regardless of the
		738	actual error value) and the C<nlink> value is forced to zero (if the stat
		739	was successful then nlink is guaranteed to be non-zero).
		740
		741	See also the next two entries for more info.
		742
		743	=item ... = $w->attr
		744
		745	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		746	the values most recently detected by EV. See the next entry for more info.
		747
		748	=item ... = $w->prev
		749
		750	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		751	the previous set of values, before the change.
		752
		753	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		754	to the values found I<before> a change was detected, while C<< $w->attr >>
		755	returns the values found leading to the change detection. The difference (if any)
		756	between C<prev> and C<attr> is what triggered the callback.
		757
		758	If you did something to the filesystem object and do not want to trigger
		759	yet another change, you can call C<stat> to update EV's idea of what the
		760	current attributes are.
		761
		762	=item $w->set ($path, $interval)
		763
		764	Reconfigures the watcher, see the constructor above for details. Can be
		765	called at any time.
		766
		767	=item $current_path = $w->path
		768
		769	=item $old_path = $w->path ($new_path)
		770
		771	Returns the previously set path and optionally set a new one.
		772
		773	=item $current_interval = $w->interval
		774
		775	=item $old_interval = $w->interval ($new_interval)
		776
		777	Returns the previously set interval and optionally set a new one. Can be
		778	used to query the actual interval used.
		779
		780	=back
		781
		782
		783	=head3 IDLE WATCHERS - when you've got nothing better to do...
		784
		785	=over 4
452		786
453	=item $w = EV::idle $callback	787	=item $w = EV::idle $callback
454		788
455	=item $w = EV::idle_ns $callback	789	=item $w = EV::idle_ns $callback
456		790
457	Call the callback when there are no pending io, timer/periodic, signal or	791	=item $w = $loop->idle ($callback)
458	child events, i.e. when the process is idle.	792
		793	=item $w = $loop->idle_ns ($callback)
		794
		795	Call the callback when there are no other pending watchers of the same or
		796	higher priority (excluding check, prepare and other idle watchers of the
		797	same or lower priority, of course). They are called idle watchers because
		798	when the watcher is the highest priority pending event in the process, the
		799	process is considered to be idle at that priority.
		800
		801	If you want a watcher that is only ever called when I<no> other events are
		802	outstanding you have to set the priority to C<EV::MINPRI>.
459		803
460	The process will not block as long as any idle watchers are active, and	804	The process will not block as long as any idle watchers are active, and
461	they will be called repeatedly until stopped.	805	they will be called repeatedly until stopped.
462		806
		807	For example, if you have idle watchers at priority C<0> and C<1>, and
		808	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		809	and the I/O watcher will always run when ready. Only when the idle watcher
		810	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		811	pending with the C<0>-priority idle watcher be invoked.
		812
463	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	813	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
464		814
		815	=back
		816
		817
		818	=head3 PREPARE WATCHERS - customise your event loop!
		819
		820	=over 4
465		821
466	=item $w = EV::prepare $callback	822	=item $w = EV::prepare $callback
467		823
468	=item $w = EV::prepare_ns $callback	824	=item $w = EV::prepare_ns $callback
		825
		826	=item $w = $loop->prepare ($callback)
		827
		828	=item $w = $loop->prepare_ns ($callback)
469		829
470	Call the callback just before the process would block. You can still	830	Call the callback just before the process would block. You can still
471	create/modify any watchers at this point.	831	create/modify any watchers at this point.
472		832
473	See the EV::check watcher, below, for explanations and an example.	833	See the EV::check watcher, below, for explanations and an example.
474		834
475	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	835	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
476		836
		837	=back
		838
		839
		840	=head3 CHECK WATCHERS - customise your event loop even more!
		841
		842	=over 4
477		843
478	=item $w = EV::check $callback	844	=item $w = EV::check $callback
479		845
480	=item $w = EV::check_ns $callback	846	=item $w = EV::check_ns $callback
		847
		848	=item $w = $loop->check ($callback)
		849
		850	=item $w = $loop->check_ns ($callback)
481		851
482	Call the callback just after the process wakes up again (after it has	852	Call the callback just after the process wakes up again (after it has
483	gathered events), but before any other callbacks have been invoked.	853	gathered events), but before any other callbacks have been invoked.
484		854
485	This is used to integrate other event-based software into the EV	855	This is used to integrate other event-based software into the EV
…		…
493	# do nothing unless active	863	# do nothing unless active
494	$dispatcher->{_event_queue_h}	864	$dispatcher->{_event_queue_h}
495	or return;	865	or return;
496		866
497	# make the dispatcher handle any outstanding stuff	867	# make the dispatcher handle any outstanding stuff
		868	... not shown
498		869
499	# create an IO watcher for each and every socket	870	# create an I/O watcher for each and every socket
500	@snmp_watcher = (	871	@snmp_watcher = (
501	(map { EV::io $_, EV::READ, sub { } }	872	(map { EV::io $_, EV::READ, sub { } }
502	keys %{ $dispatcher->{_descriptors} }),	873	keys %{ $dispatcher->{_descriptors} }),
		874
		875	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		876	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		877	0, sub { },
503	);	878	);
504
505	# if there are any timeouts, also create a timer
506	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
507	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
508	};	879	};
509		880
510	The callbacks are irrelevant, the only purpose of those watchers is	881	The callbacks are irrelevant (and are not even being called), the
511	to wake up the process as soon as one of those events occurs (socket	882	only purpose of those watchers is to wake up the process as soon as
512	readable, or timer timed out). The corresponding EV::check watcher will then	883	one of those events occurs (socket readable, or timer timed out). The
513	clean up:	884	corresponding EV::check watcher will then clean up:
514		885
515	our $snmp_check = EV::check sub {	886	our $snmp_check = EV::check sub {
516	# destroy all watchers	887	# destroy all watchers
517	@snmp_watcher = ();	888	@snmp_watcher = ();
518		889
519	# make the dispatcher handle any new stuff	890	# make the dispatcher handle any new stuff
		891	... not shown
520	};	892	};
521		893
522	The callbacks of the created watchers will not be called as the watchers	894	The callbacks of the created watchers will not be called as the watchers
523	are destroyed before this cna happen (remember EV::check gets called	895	are destroyed before this cna happen (remember EV::check gets called
524	first).	896	first).
525		897
526	The C<check_ns> variant doesn't start (activate) the newly created watcher.	898	The C<check_ns> variant doesn't start (activate) the newly created watcher.
527		899
528	=back	900	=back
529		901
		902
		903	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		904
		905	Fork watchers are called when a C<fork ()> was detected. The invocation
		906	is done before the event loop blocks next and before C<check> watchers
		907	are being called, and only in the child after the fork.
		908
		909	=over 4
		910
		911	=item $w = EV::fork $callback
		912
		913	=item $w = EV::fork_ns $callback
		914
		915	=item $w = $loop->fork ($callback)
		916
		917	=item $w = $loop->fork_ns ($callback)
		918
		919	Call the callback before the event loop is resumed in the child process
		920	after a fork.
		921
		922	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		923
		924	=back
		925
		926
		927	=head3 EMBED WATCHERS - when one backend isn't enough...
		928
		929	This is a rather advanced watcher type that lets you embed one event loop
		930	into another (currently only IO events are supported in the embedded
		931	loop, other types of watchers might be handled in a delayed or incorrect
		932	fashion and must not be used).
		933
		934	See the libev documentation at
		935	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		936	for more details.
		937
		938	In short, this watcher is most useful on BSD systems without working
		939	kqueue to still be able to handle a large number of sockets:
		940
		941	my $socket_loop;
		942
		943	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		944	if (
		945	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		946	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		947	) {
		948	# use kqueue for sockets
		949	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		950	}
		951
		952	# use the default loop otherwise
		953	$socket_loop \|\|= EV::default_loop;
		954
		955	=over 4
		956
		957	=item $w = EV::embed $otherloop, $callback
		958
		959	=item $w = EV::embed_ns $otherloop, $callback
		960
		961	=item $w = $loop->embed ($otherloop, $callback)
		962
		963	=item $w = $loop->embed_ns ($otherloop, $callback)
		964
		965	Call the callback when the embedded event loop (C<$otherloop>) has any
		966	I/O activity. The C<$callback> should alwas be specified as C<undef> in
		967	this version of EV, which means the embedded event loop will be managed
		968	automatically.
		969
		970	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		971
		972	=back
		973
		974	=head3 ASYNC WATCHERS - how to wake up another event loop
		975
		976	Async watchers are provided by EV, but have little use in perl directly, as perl
		977	neither supports threads nor direct access to signal handlers or other
		978	contexts where they could be of value.
		979
		980	It is, however, possible to use them from the XS level.
		981
		982	Please see the libev documentation for further details.
		983
		984
		985	=head1 PERL SIGNALS
		986
		987	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		988	with EV is as the same as any other C library: Perl-signals will only be
		989	handled when Perl runs, which means your signal handler might be invoked
		990	only the next time an event callback is invoked.
		991
		992	The solution is to use EV signal watchers (see C<EV::signal>), which will
		993	ensure proper operations with regards to other event watchers.
		994
		995	If you cannot do this for whatever reason, you can also force a watcher
		996	to be called on every event loop iteration by installing a C<EV::check>
		997	watcher:
		998
		999	my $async_check = EV::check sub { };
		1000
		1001	This ensures that perl gets into control for a short time to handle any
		1002	pending signals, and also ensures (slightly) slower overall operation.
		1003
530	=head1 THREADS	1004	=head1 THREADS
531		1005
532	Threads are not supported by this in any way. Perl pseudo-threads is evil	1006	Threads are not supported by this module in any way. Perl pseudo-threads
533	stuff and must die.	1007	is evil stuff and must die. As soon as Perl gains real threads I will work
		1008	on thread support for it.
		1009
		1010	=head1 FORK
		1011
		1012	Most of the "improved" event delivering mechanisms of modern operating
		1013	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1014	not supported and usually destructive). Libev makes it possible to work
		1015	around this by having a function that recreates the kernel state after
		1016	fork in the child.
		1017
		1018	On non-win32 platforms, this module requires the pthread_atfork
		1019	functionality to do this automatically for you. This function is quite
		1020	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1021	negligible, because everything the function currently does is set a flag
		1022	that is checked only when the event loop gets used the next time, so when
		1023	you do fork but not use EV, the overhead is minimal.
		1024
		1025	On win32, there is no notion of fork so all this doesn't apply, of course.
534		1026
535	=cut	1027	=cut
536		1028
537	our $DIED = sub {	1029	our $DIED = sub {
538	warn "EV: error in callback (ignoring): $@";	1030	warn "EV: error in callback (ignoring): $@";
539	};	1031	};
540		1032
541	default_loop	1033	default_loop
542	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1034	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
543		1035
544	1;	1036	1;
545		1037
546	=head1 SEE ALSO	1038	=head1 SEE ALSO
547		1039
548	L<EV::DNS>.	1040	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1041	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1042	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP).
549		1043
550	=head1 AUTHOR	1044	=head1 AUTHOR
551		1045
552	Marc Lehmann <schmorp@schmorp.de>	1046	Marc Lehmann <schmorp@schmorp.de>
553	http://home.schmorp.de/	1047	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.41 by root, Fri Nov 16 10:42:40 2007 UTC vs. Revision 1.86 by root, Wed Apr 2 11:00:58 2008 UTC

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Revision 1.41 by root, Fri Nov 16 10:42:40 2007 UTC vs.
Revision 1.86 by root, Wed Apr 2 11:00:58 2008 UTC