[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 1.94 by root, Tue May 20 23:54:05 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://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 = '0.9';	79	our $VERSION = '3.4';
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 fucntion automatically, at some performance loss (refer to the libev
		136	documentation).
		137
		138	=item $loop = EV::default_loop [$flags]
		139
		140	Return the default loop (which is a singleton object).
		141
		142	=back
		143
75		144
76	=head1 BASIC INTERFACE	145	=head1 BASIC INTERFACE
77		146
78	=over 4	147	=over 4
79		148
80	=item $EV::DIED	149	=item $EV::DIED
81		150
82	Must contain a reference to a function that is called when a callback	151	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	152	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	153	informative message and continues.
85		154
86	If this callback throws an exception it will be silently ignored.	155	If this callback throws an exception it will be silently ignored.
87		156
		157	=item $flags = EV::supported_backends
		158
		159	=item $flags = EV::recommended_backends
		160
		161	=item $flags = EV::embeddable_backends
		162
		163	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		164	instance of EV, the set of recommended backends (supposed to be good) for
		165	this platform and the set of embeddable backends (see EMBED WATCHERS).
		166
		167	=item EV::sleep $seconds
		168
		169	Block the process for the given number of (fractional) seconds.
		170
88	=item $time = EV::time	171	=item $time = EV::time
89		172
90	Returns the current time in (fractional) seconds since the epoch.	173	Returns the current time in (fractional) seconds since the epoch.
91		174
92	=item $time = EV::now	175	=item $time = EV::now
		176
		177	=item $time = $loop->now
93		178
94	Returns the time the last event loop iteration has been started. This	179	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	180	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	181	usually faster then calling EV::time.
97		182
98	=item $method = EV::method	183	=item $backend = EV::backend
		184
		185	=item $backend = $loop->backend
99		186
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	187	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	188	or EV::METHOD_EPOLL).
102		189
103	=item EV::loop [$flags]	190	=item EV::loop [$flags]
		191
		192	=item $loop->loop ([$flags])
104		193
105	Begin checking for events and calling callbacks. It returns when a	194	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	195	callback calls EV::unloop.
107		196
108	The $flags argument can be one of the following:	197	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	200	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	201	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		202
114	=item EV::unloop [$how]	203	=item EV::unloop [$how]
115		204
		205	=item $loop->unloop ([$how])
		206
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	207	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	208	innermost call to EV::loop return.
118		209
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	210	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	211	fast as possible.
121		212
122	=back	213	=item $count = EV::loop_count
123		214
124	=head2 WATCHER	215	=item $count = $loop->loop_count
		216
		217	Return the number of times the event loop has polled for new
		218	events. Sometiems useful as a generation counter.
		219
		220	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		221
		222	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		223
		224	This function rolls together an I/O and a timer watcher for a single
		225	one-shot event without the need for managing a watcher object.
		226
		227	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		228	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		229	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		230	you do not want to wait for some I/O event, specify C<undef> for
		231	C<$fh_or_undef> and C<0> for C<$events>).
		232
		233	If timeout is C<undef> or negative, then there will be no
		234	timeout. Otherwise a EV::timer with this value will be started.
		235
		236	When an error occurs or either the timeout or I/O watcher triggers, then
		237	the callback will be called with the received event set (in general
		238	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		239	C<EV::WRITE> and C<EV::TIMEOUT>).
		240
		241	EV::once doesn't return anything: the watchers stay active till either
		242	of them triggers, then they will be stopped and freed, and the callback
		243	invoked.
		244
		245	=item EV::feed_fd_event ($fd, $revents)
		246
		247	=item $loop->feed_fd_event ($fd, $revents)
		248
		249	Feed an event on a file descriptor into EV. EV will react to this call as
		250	if the readyness notifications specified by C<$revents> (a combination of
		251	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		252
		253	=item EV::feed_signal_event ($signal)
		254
		255	Feed a signal event into EV. EV will react to this call as if the signal
		256	specified by C<$signal> had occured.
		257
		258	=item EV::set_io_collect_interval $time
		259
		260	=item $loop->set_io_collect_interval ($time)
		261
		262	=item EV::set_timeout_collect_interval $time
		263
		264	=item $loop->set_timeout_collect_interval ($time)
		265
		266	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		267	wait interval for timer events. See the libev documentation at
		268	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		269	a more detailed discussion.
		270
		271	=back
		272
		273
		274	=head1 WATCHER OBJECTS
125		275
126	A watcher is an object that gets created to record your interest in some	276	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	277	event. For instance, if you want to wait for STDIN to become readable, you
128	would create an EV::io watcher for that:	278	would create an EV::io watcher for that:
129		279
130	my $watcher = EV::io *STDIN, EV::READ, sub {	280	my $watcher = EV::io *STDIN, EV::READ, sub {
131	my ($watcher, $revents) = @_;	281	my ($watcher, $revents) = @_;
132	warn "yeah, STDIN should not be readable without blocking!\n"	282	warn "yeah, STDIN should now be readable without blocking!\n"
133	};	283	};
134		284
135	All watchers can be active (waiting for events) or inactive (paused). Only	285	All watchers can be active (waiting for events) or inactive (paused). Only
136	active watchers will have their callbacks invoked. All callbacks will be	286	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	287	called with at least two arguments: the watcher and a bitmask of received
138	events.	288	events.
139		289
140	Each watcher type has its associated bit in revents, so you can use the	290	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	291	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,	292	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	293	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	294	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
145	uses EV::TIMEOUT).	295	uses EV::TIMEOUT).
146		296
147	In the rare case where one wants to create a watcher but not start it at	297	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	298	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
154		304
155	Also, all methods changing some aspect of a watcher (->set, ->priority,	305	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,	306	->fh and so on) automatically stop and start it again if it is active,
157	which means pending events get lost.	307	which means pending events get lost.
158		308
159	=head2 WATCHER TYPES	309	=head2 COMMON WATCHER METHODS
160		310
161	Now lets move to the existing watcher types and asociated methods.	311	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		312
168	=over 4	313	=over 4
169		314
170	=item $w->start	315	=item $w->start
171		316
…		…
175		320
176	=item $w->stop	321	=item $w->stop
177		322
178	Stop a watcher if it is active. Also clear any pending events (events that	323	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),	324	have been received but that didn't yet result in a callback invocation),
180	regardless of wether the watcher was active or not.	325	regardless of whether the watcher was active or not.
181		326
182	=item $bool = $w->is_active	327	=item $bool = $w->is_active
183		328
184	Returns true if the watcher is active, false otherwise.	329	Returns true if the watcher is active, false otherwise.
185		330
…		…
210	watchers with higher priority will be invoked first. The valid range of	355	watchers with higher priority will be invoked first. The valid range of
211	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	356	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
212	-2). If the priority is outside this range it will automatically be	357	-2). If the priority is outside this range it will automatically be
213	normalised to the nearest valid priority.	358	normalised to the nearest valid priority.
214		359
215	The default priority of any newly-created weatcher is 0.	360	The default priority of any newly-created watcher is 0.
216		361
		362	Note that the priority semantics have not yet been fleshed out and are
		363	subject to almost certain change.
		364
217	=item $w->trigger ($revents)	365	=item $w->invoke ($revents)
218		366
219	Call the callback now with the given event mask.	367	Call the callback now with the given event mask.
220		368
		369	=item $w->feed_event ($revents)
		370
		371	Feed some events on this watcher into EV. EV will react to this call as if
		372	the watcher had received the given C<$revents> mask.
		373
		374	=item $revents = $w->clear_pending
		375
		376	If the watcher is pending, this function clears its pending status and
		377	returns its C<$revents> bitset (as if its callback was invoked). If the
		378	watcher isn't pending it does nothing and returns C<0>.
		379
		380	=item $previous_state = $w->keepalive ($bool)
		381
		382	Normally, C<EV::loop> will return when there are no active watchers
		383	(which is a "deadlock" because no progress can be made anymore). This is
		384	convinient because it allows you to start your watchers (and your jobs),
		385	call C<EV::loop> once and when it returns you know that all your jobs are
		386	finished (or they forgot to register some watchers for their task :).
		387
		388	Sometimes, however, this gets in your way, for example when the module
		389	that calls C<EV::loop> (usually the main program) is not the same module
		390	as a long-living watcher (for example a DNS client module written by
		391	somebody else even). Then you might want any outstanding requests to be
		392	handled, but you would not want to keep C<EV::loop> from returning just
		393	because you happen to have this long-running UDP port watcher.
		394
		395	In this case you can clear the keepalive status, which means that even
		396	though your watcher is active, it won't keep C<EV::loop> from returning.
		397
		398	The initial value for keepalive is true (enabled), and you cna change it
		399	any time.
		400
		401	Example: Register an I/O watcher for some UDP socket but do not keep the
		402	event loop from running just because of that watcher.
		403
		404	my $udp_socket = ...
		405	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		406	$1000udp_watcher->keepalive (0);
		407
		408	=item $loop = $w->loop
		409
		410	Return the loop that this watcher is attached to.
		411
		412	=back
		413
		414
		415	=head1 WATCHER TYPES
		416
		417	Each of the following subsections describes a single watcher type.
		418
		419	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		420
		421	=over 4
221		422
222	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	423	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
223		424
224	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	425	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
225		426
		427	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		428
		429	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		430
226	As long as the returned watcher object is alive, call the C<$callback>	431	As long as the returned watcher object is alive, call the C<$callback>
227	when the events specified in C<$eventmask>.	432	when at least one of events specified in C<$eventmask> occurs.
228		433
229	The $eventmask can be one or more of these constants ORed together:	434	The $eventmask can be one or more of these constants ORed together:
230		435
231	EV::READ wait until read() wouldn't block anymore	436	EV::READ wait until read() wouldn't block anymore
232	EV::WRITE wait until write() wouldn't block anymore	437	EV::WRITE wait until write() wouldn't block anymore
…		…
248		453
249	=item $old_eventmask = $w->events ($new_eventmask)	454	=item $old_eventmask = $w->events ($new_eventmask)
250		455
251	Returns the previously set event mask and optionally set a new one.	456	Returns the previously set event mask and optionally set a new one.
252		457
		458	=back
		459
		460
		461	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		462
		463	=over 4
253		464
254	=item $w = EV::timer $after, $repeat, $callback	465	=item $w = EV::timer $after, $repeat, $callback
255		466
256	=item $w = EV::timer_ns $after, $repeat, $callback	467	=item $w = EV::timer_ns $after, $repeat, $callback
257		468
258	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	469	=item $w = $loop->timer ($after, $repeat, $callback)
259	the timer will be restarted (with the $repeat value as $after) after the	470
260	callback returns.	471	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		472
		473	Calls the callback after C<$after> seconds (which may be fractional). If
		474	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		475	value as $after) after the callback returns.
261		476
262	This means that the callback would be called roughly after C<$after>	477	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	478	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	479	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,	480	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
271		486
272	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	487	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
273		488
274	=item $w->set ($after, $repeat)	489	=item $w->set ($after, $repeat)
275		490
276	Reconfigures the watcher, see the constructor above for details. Can be at	491	Reconfigures the watcher, see the constructor above for details. Can be called at
277	any time.	492	any time.
278		493
279	=item $w->again	494	=item $w->again
280		495
281	Similar to the C<start> method, but has special semantics for repeating timers:	496	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
292	This behaviour is useful when you have a timeout for some IO	507	This behaviour is useful when you have a timeout for some IO
293	operation. You create a timer object with the same value for C<$after> and	508	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	509	C<$repeat>, and then, in the read/write watcher, run the C<again> method
295	on the timeout.	510	on the timeout.
296		511
		512	=back
		513
		514
		515	=head3 PERIODIC WATCHERS - to cron or not to cron?
		516
		517	=over 4
297		518
298	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	519	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
299		520
300	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	521	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		522
		523	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		524
		525	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
301		526
302	Similar to EV::timer, but is not based on relative timeouts but on	527	Similar to EV::timer, but is not based on relative timeouts but on
303	absolute times. Apart from creating "simple" timers that trigger "at" the	528	absolute times. Apart from creating "simple" timers that trigger "at" the
304	specified time, it can also be used for non-drifting absolute timers and	529	specified time, it can also be used for non-drifting absolute timers and
305	more complex, cron-like, setups that are not adversely affected by time	530	more complex, cron-like, setups that are not adversely affected by time
…		…
315	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	540	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
316	will not adjust when a time jump occurs, that is, if it is to be run	541	will not adjust when a time jump occurs, that is, if it is to be run
317	at January 1st 2011 then it will run when the system time reaches or	542	at January 1st 2011 then it will run when the system time reaches or
318	surpasses this time.	543	surpasses this time.
319		544
320	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	545	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
321		546
322	In this mode the watcher will always be scheduled to time out at the	547	In this mode the watcher will always be scheduled to time out at the
323	next C<$at + N * $interval> time (for some integer N) and then repeat,	548	next C<$at + N * $interval> time (for some integer N) and then repeat,
324	regardless of any time jumps.	549	regardless of any time jumps.
325		550
…		…
343	time the periodic watcher gets scheduled, the reschedule callback	568	time the periodic watcher gets scheduled, the reschedule callback
344	($reschedule_cb) will be called with the watcher as first, and the current	569	($reschedule_cb) will be called with the watcher as first, and the current
345	time as second argument.	570	time as second argument.
346		571
347	I<This callback MUST NOT stop or destroy this or any other periodic	572	I<This callback MUST NOT stop or destroy this or any other periodic
348	watcher, ever>. If you need to stop it, return 1e30 and stop it	573	watcher, ever, and MUST NOT call any event loop functions or methods>. If
349	afterwards.	574	you need to stop it, return 1e30 and stop it afterwards. You may create
		575	and start a C<EV::prepare> watcher for this task.
350		576
351	It must return the next time to trigger, based on the passed time value	577	It must return the next time to trigger, based on the passed time value
352	(that is, the lowest time value larger than to the second argument). It	578	(that is, the lowest time value larger than or equal to to the second
353	will usually be called just before the callback will be triggered, but	579	argument). It will usually be called just before the callback will be
354	might be called at other times, too.	580	triggered, but might be called at other times, too.
355		581
356	This can be used to create very complex timers, such as a timer that	582	This can be used to create very complex timers, such as a timer that
357	triggers on each midnight, local time (actually 24 hours after the last	583	triggers on each midnight, local time (actually 24 hours after the last
358	midnight, to keep the example simple. If you know a way to do it correctly	584	midnight, to keep the example simple. If you know a way to do it correctly
359	in about the same space (without requiring elaborate modules), drop me a	585	in about the same space (without requiring elaborate modules), drop me a
…		…
373		599
374	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	600	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
375		601
376	=item $w->set ($at, $interval, $reschedule_cb)	602	=item $w->set ($at, $interval, $reschedule_cb)
377		603
378	Reconfigures the watcher, see the constructor above for details. Can be at	604	Reconfigures the watcher, see the constructor above for details. Can be called at
379	any time.	605	any time.
380		606
381	=item $w->again	607	=item $w->again
382		608
383	Simply stops and starts the watcher again.	609	Simply stops and starts the watcher again.
384		610
		611	=item $time = $w->at
		612
		613	Return the time that the watcher is expected to trigger next.
		614
		615	=back
		616
		617
		618	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		619
		620	=over 4
385		621
386	=item $w = EV::signal $signal, $callback	622	=item $w = EV::signal $signal, $callback
387		623
388	=item $w = EV::signal_ns $signal, $callback	624	=item $w = EV::signal_ns $signal, $callback
389		625
390	Call the callback when $signal is received (the signal can be specified	626	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).	627	number or by name, just as with C<kill> or C<%SIG>).
392		628
393	EV will grab the signal for the process (the kernel only allows one	629	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,	630	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	631	and removes it again when you stop it. Perl does the same when you
396	add/remove callbacks to %SIG, so watch out.	632	add/remove callbacks to C<%SIG>, so watch out.
397		633
398	You can have as many signal watchers per signal as you want.	634	You can have as many signal watchers per signal as you want.
399		635
400	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	636	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
401		637
402	=item $w->set ($signal)	638	=item $w->set ($signal)
403		639
404	Reconfigures the watcher, see the constructor above for details. Can be at	640	Reconfigures the watcher, see the constructor above for details. Can be
405	any time.	641	called at any time.
406		642
407	=item $current_signum = $w->signal	643	=item $current_signum = $w->signal
408		644
409	=item $old_signum = $w->signal ($new_signal)	645	=item $old_signum = $w->signal ($new_signal)
410		646
411	Returns the previously set signal (always as a number not name) and	647	Returns the previously set signal (always as a number not name) and
412	optionally set a new one.	648	optionally set a new one.
413		649
		650	=back
414		651
		652
		653	=head3 CHILD WATCHERS - watch out for process status changes
		654
		655	=over 4
		656
415	=item $w = EV::child $pid, $callback	657	=item $w = EV::child $pid, $trace, $callback
416		658
417	=item $w = EV::child_ns $pid, $callback	659	=item $w = EV::child_ns $pid, $trace, $callback
		660
		661	=item $w = $loop->child ($pid, $trace, $callback)
		662
		663	=item $w = $loop->child_ns ($pid, $trace, $callback)
418		664
419	Call the callback when a status change for pid C<$pid> (or any pid	665	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	666	if C<$pid> is 0) has been received (a status change happens when the
		667	process terminates or is killed, or, when trace is true, additionally when
		668	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	669	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
422	changed/zombie children and call the callback.	670	changed/zombie children and call the callback.
423		671
424	You can access both status and pid by using the C<rstatus> and C<rpid>	672	It is valid (and fully supported) to install a child watcher after a child
425	methods on the watcher object.	673	has exited but before the event loop has started its next iteration (for
		674	example, first you C<fork>, then the new child process might exit, and
		675	only then do you install a child watcher in the parent for the new pid).
426		676
		677	You can access both exit (or tracing) status and pid by using the
		678	C<rstatus> and C<rpid> methods on the watcher object.
		679
427	You can have as many pid watchers per pid as you want.	680	You can have as many pid watchers per pid as you want, they will all be
		681	called.
428		682
429	The C<child_ns> variant doesn't start (activate) the newly created watcher.	683	The C<child_ns> variant doesn't start (activate) the newly created watcher.
430		684
431	=item $w->set ($pid)	685	=item $w->set ($pid, $trace)
432		686
433	Reconfigures the watcher, see the constructor above for details. Can be at	687	Reconfigures the watcher, see the constructor above for details. Can be called at
434	any time.	688	any time.
435		689
436	=item $current_pid = $w->pid	690	=item $current_pid = $w->pid
437
438	=item $old_pid = $w->pid ($new_pid)
439		691
440	Returns the previously set process id and optionally set a new one.	692	Returns the previously set process id and optionally set a new one.
441		693
442	=item $exit_status = $w->rstatus	694	=item $exit_status = $w->rstatus
443		695
…		…
447	=item $pid = $w->rpid	699	=item $pid = $w->rpid
448		700
449	Return the pid of the awaited child (useful when you have installed a	701	Return the pid of the awaited child (useful when you have installed a
450	watcher for all pids).	702	watcher for all pids).
451		703
		704	=back
		705
		706
		707	=head3 STAT WATCHERS - did the file attributes just change?
		708
		709	=over 4
		710
		711	=item $w = EV::stat $path, $interval, $callback
		712
		713	=item $w = EV::stat_ns $path, $interval, $callback
		714
		715	=item $w = $loop->stat ($path, $interval, $callback)
		716
		717	=item $w = $loop->stat_ns ($path, $interval, $callback)
		718
		719	Call the callback when a file status change has been detected on
		720	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		721	to "path does not exist" is a status change like any other.
		722
		723	The C<$interval> is a recommended polling interval for systems where
		724	OS-supported change notifications don't exist or are not supported. If
		725	you use C<0> then an unspecified default is used (which is highly
		726	recommended!), which is to be expected to be around five seconds usually.
		727
		728	This watcher type is not meant for massive numbers of stat watchers,
		729	as even with OS-supported change notifications, this can be
		730	resource-intensive.
		731
		732	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		733
		734	=item ... = $w->stat
		735
		736	This call is very similar to the perl C<stat> built-in: It stats (using
		737	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		738	well as EV's idea of the current stat values) to the values found.
		739
		740	In scalar context, a boolean is return indicating success or failure of
		741	the stat. In list context, the same 13-value list as with stat is returned
		742	(except that the blksize and blocks fields are not reliable).
		743
		744	In the case of an error, errno is set to C<ENOENT> (regardless of the
		745	actual error value) and the C<nlink> value is forced to zero (if the stat
		746	was successful then nlink is guaranteed to be non-zero).
		747
		748	See also the next two entries for more info.
		749
		750	=item ... = $w->attr
		751
		752	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		753	the values most recently detected by EV. See the next entry for more info.
		754
		755	=item ... = $w->prev
		756
		757	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		758	the previous set of values, before the change.
		759
		760	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		761	to the values found I<before> a change was detected, while C<< $w->attr >>
		762	returns the values found leading to the change detection. The difference (if any)
		763	between C<prev> and C<attr> is what triggered the callback.
		764
		765	If you did something to the filesystem object and do not want to trigger
		766	yet another change, you can call C<stat> to update EV's idea of what the
		767	current attributes are.
		768
		769	=item $w->set ($path, $interval)
		770
		771	Reconfigures the watcher, see the constructor above for details. Can be
		772	called at any time.
		773
		774	=item $current_path = $w->path
		775
		776	=item $old_path = $w->path ($new_path)
		777
		778	Returns the previously set path and optionally set a new one.
		779
		780	=item $current_interval = $w->interval
		781
		782	=item $old_interval = $w->interval ($new_interval)
		783
		784	Returns the previously set interval and optionally set a new one. Can be
		785	used to query the actual interval used.
		786
		787	=back
		788
		789
		790	=head3 IDLE WATCHERS - when you've got nothing better to do...
		791
		792	=over 4
452		793
453	=item $w = EV::idle $callback	794	=item $w = EV::idle $callback
454		795
455	=item $w = EV::idle_ns $callback	796	=item $w = EV::idle_ns $callback
456		797
457	Call the callback when there are no pending io, timer/periodic, signal or	798	=item $w = $loop->idle ($callback)
458	child events, i.e. when the process is idle.	799
		800	=item $w = $loop->idle_ns ($callback)
		801
		802	Call the callback when there are no other pending watchers of the same or
		803	higher priority (excluding check, prepare and other idle watchers of the
		804	same or lower priority, of course). They are called idle watchers because
		805	when the watcher is the highest priority pending event in the process, the
		806	process is considered to be idle at that priority.
		807
		808	If you want a watcher that is only ever called when I<no> other events are
		809	outstanding you have to set the priority to C<EV::MINPRI>.
459		810
460	The process will not block as long as any idle watchers are active, and	811	The process will not block as long as any idle watchers are active, and
461	they will be called repeatedly until stopped.	812	they will be called repeatedly until stopped.
462		813
		814	For example, if you have idle watchers at priority C<0> and C<1>, and
		815	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		816	and the I/O watcher will always run when ready. Only when the idle watcher
		817	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		818	pending with the C<0>-priority idle watcher be invoked.
		819
463	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	820	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
464		821
		822	=back
		823
		824
		825	=head3 PREPARE WATCHERS - customise your event loop!
		826
		827	=over 4
465		828
466	=item $w = EV::prepare $callback	829	=item $w = EV::prepare $callback
467		830
468	=item $w = EV::prepare_ns $callback	831	=item $w = EV::prepare_ns $callback
		832
		833	=item $w = $loop->prepare ($callback)
		834
		835	=item $w = $loop->prepare_ns ($callback)
469		836
470	Call the callback just before the process would block. You can still	837	Call the callback just before the process would block. You can still
471	create/modify any watchers at this point.	838	create/modify any watchers at this point.
472		839
473	See the EV::check watcher, below, for explanations and an example.	840	See the EV::check watcher, below, for explanations and an example.
474		841
475	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	842	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
476		843
		844	=back
		845
		846
		847	=head3 CHECK WATCHERS - customise your event loop even more!
		848
		849	=over 4
477		850
478	=item $w = EV::check $callback	851	=item $w = EV::check $callback
479		852
480	=item $w = EV::check_ns $callback	853	=item $w = EV::check_ns $callback
		854
		855	=item $w = $loop->check ($callback)
		856
		857	=item $w = $loop->check_ns ($callback)
481		858
482	Call the callback just after the process wakes up again (after it has	859	Call the callback just after the process wakes up again (after it has
483	gathered events), but before any other callbacks have been invoked.	860	gathered events), but before any other callbacks have been invoked.
484		861
485	This is used to integrate other event-based software into the EV	862	This is used to integrate other event-based software into the EV
…		…
493	# do nothing unless active	870	# do nothing unless active
494	$dispatcher->{_event_queue_h}	871	$dispatcher->{_event_queue_h}
495	or return;	872	or return;
496		873
497	# make the dispatcher handle any outstanding stuff	874	# make the dispatcher handle any outstanding stuff
		875	... not shown
498		876
499	# create an IO watcher for each and every socket	877	# create an I/O watcher for each and every socket
500	@snmp_watcher = (	878	@snmp_watcher = (
501	(map { EV::io $_, EV::READ, sub { } }	879	(map { EV::io $_, EV::READ, sub { } }
502	keys %{ $dispatcher->{_descriptors} }),	880	keys %{ $dispatcher->{_descriptors} }),
		881
		882	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		883	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		884	0, sub { },
503	);	885	);
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	};	886	};
509		887
510	The callbacks are irrelevant, the only purpose of those watchers is	888	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	889	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	890	one of those events occurs (socket readable, or timer timed out). The
513	clean up:	891	corresponding EV::check watcher will then clean up:
514		892
515	our $snmp_check = EV::check sub {	893	our $snmp_check = EV::check sub {
516	# destroy all watchers	894	# destroy all watchers
517	@snmp_watcher = ();	895	@snmp_watcher = ();
518		896
519	# make the dispatcher handle any new stuff	897	# make the dispatcher handle any new stuff
		898	... not shown
520	};	899	};
521		900
522	The callbacks of the created watchers will not be called as the watchers	901	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	902	are destroyed before this cna happen (remember EV::check gets called
524	first).	903	first).
525		904
526	The C<check_ns> variant doesn't start (activate) the newly created watcher.	905	The C<check_ns> variant doesn't start (activate) the newly created watcher.
527		906
528	=back	907	=back
529		908
		909
		910	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		911
		912	Fork watchers are called when a C<fork ()> was detected. The invocation
		913	is done before the event loop blocks next and before C<check> watchers
		914	are being called, and only in the child after the fork.
		915
		916	=over 4
		917
		918	=item $w = EV::fork $callback
		919
		920	=item $w = EV::fork_ns $callback
		921
		922	=item $w = $loop->fork ($callback)
		923
		924	=item $w = $loop->fork_ns ($callback)
		925
		926	Call the callback before the event loop is resumed in the child process
		927	after a fork.
		928
		929	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		930
		931	=back
		932
		933
		934	=head3 EMBED WATCHERS - when one backend isn't enough...
		935
		936	This is a rather advanced watcher type that lets you embed one event loop
		937	into another (currently only IO events are supported in the embedded
		938	loop, other types of watchers might be handled in a delayed or incorrect
		939	fashion and must not be used).
		940
		941	See the libev documentation at
		942	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		943	for more details.
		944
		945	In short, this watcher is most useful on BSD systems without working
		946	kqueue to still be able to handle a large number of sockets:
		947
		948	my $socket_loop;
		949
		950	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		951	if (
		952	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		953	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		954	) {
		955	# use kqueue for sockets
		956	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		957	}
		958
		959	# use the default loop otherwise
		960	$socket_loop \|\|= EV::default_loop;
		961
		962	=over 4
		963
		964	=item $w = EV::embed $otherloop, $callback
		965
		966	=item $w = EV::embed_ns $otherloop, $callback
		967
		968	=item $w = $loop->embed ($otherloop, $callback)
		969
		970	=item $w = $loop->embed_ns ($otherloop, $callback)
		971
		972	Call the callback when the embedded event loop (C<$otherloop>) has any
		973	I/O activity. The C<$callback> should alwas be specified as C<undef> in
		974	this version of EV, which means the embedded event loop will be managed
		975	automatically.
		976
		977	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		978
		979	=back
		980
		981	=head3 ASYNC WATCHERS - how to wake up another event loop
		982
		983	Async watchers are provided by EV, but have little use in perl directly, as perl
		984	neither supports threads nor direct access to signal handlers or other
		985	contexts where they could be of value.
		986
		987	It is, however, possible to use them from the XS level.
		988
		989	Please see the libev documentation for further details.
		990
		991	=over 4
		992
		993	=item $w = EV::async $callback
		994
		995	=item $w = EV::async_ns $callback
		996
		997	=item $w->send
		998
		999	=item $bool = $w->async_pending
		1000
		1001	=back
		1002
		1003
		1004	=head1 PERL SIGNALS
		1005
		1006	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1007	with EV is as the same as any other C library: Perl-signals will only be
		1008	handled when Perl runs, which means your signal handler might be invoked
		1009	only the next time an event callback is invoked.
		1010
		1011	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1012	ensure proper operations with regards to other event watchers.
		1013
		1014	If you cannot do this for whatever reason, you can also force a watcher
		1015	to be called on every event loop iteration by installing a C<EV::check>
		1016	watcher:
		1017
		1018	my $async_check = EV::check sub { };
		1019
		1020	This ensures that perl gets into control for a short time to handle any
		1021	pending signals, and also ensures (slightly) slower overall operation.
		1022
530	=head1 THREADS	1023	=head1 THREADS
531		1024
532	Threads are not supported by this in any way. Perl pseudo-threads is evil	1025	Threads are not supported by this module in any way. Perl pseudo-threads
533	stuff and must die.	1026	is evil stuff and must die. As soon as Perl gains real threads I will work
		1027	on thread support for it.
		1028
		1029	=head1 FORK
		1030
		1031	Most of the "improved" event delivering mechanisms of modern operating
		1032	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1033	not supported and usually destructive). Libev makes it possible to work
		1034	around this by having a function that recreates the kernel state after
		1035	fork in the child.
		1036
		1037	On non-win32 platforms, this module requires the pthread_atfork
		1038	functionality to do this automatically for you. This function is quite
		1039	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1040	negligible, because everything the function currently does is set a flag
		1041	that is checked only when the event loop gets used the next time, so when
		1042	you do fork but not use EV, the overhead is minimal.
		1043
		1044	On win32, there is no notion of fork so all this doesn't apply, of course.
534		1045
535	=cut	1046	=cut
536		1047
537	our $DIED = sub {	1048	our $DIED = sub {
538	warn "EV: error in callback (ignoring): $@";	1049	warn "EV: error in callback (ignoring): $@";
539	};	1050	};
540		1051
541	default_loop	1052	default_loop
542	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1053	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
543		1054
544	1;	1055	1;
545		1056
546	=head1 SEE ALSO	1057	=head1 SEE ALSO
547		1058
548	L<EV::DNS>.	1059	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1060	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1061	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1062	event-loop agnostic and portable event driven programming.
549		1063
550	=head1 AUTHOR	1064	=head1 AUTHOR
551		1065
552	Marc Lehmann <schmorp@schmorp.de>	1066	Marc Lehmann <schmorp@schmorp.de>
553	http://home.schmorp.de/	1067	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 1.94 by root, Tue May 20 23:54:05 2008 UTC

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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 1.94 by root, Tue May 20 23:54:05 2008 UTC