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

Comparing EV/EV.pm (file contents):
Revision 1.36 by root, Sun Nov 11 04:14:09 2007 UTC vs.
Revision 1.91 by root, Tue May 6 12:43:58 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	};	43	};
		44
		45	# STAT CHANGES
		46	my $w = EV::stat "/etc/passwd", 10, sub {
		47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
		49	};
44		50
45	# MAINLOOP	51	# MAINLOOP
46	EV::loop; # loop until EV::loop_done is called or all watchers stop	52	EV::loop; # loop until EV::unloop is called or all watchers stop
47	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
48	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
49		55
50	=head1 DESCRIPTION	56	=head1 DESCRIPTION
51		57
52	This module provides an interface to libev	58	This module provides an interface to libev
53	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of libev
		61	itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more
		62	subtle details on watcher semantics or some discussion on the available
		63	backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just
		64	about in any case because it has much more detailed information.
		65
		66	This module is very fast and scalable. It is actually so fast that you
		67	can use it through the L<AnyEvent> module, stay portable to other event
		68	loops (if you don't rely on any watcher types not available through it)
		69	and still be faster than with any other event loop currently supported in
		70	Perl.
54		71
55	=cut	72	=cut
56		73
57	package EV;	74	package EV;
58		75
59	use strict;	76	use strict;
60		77
61	BEGIN {	78	BEGIN {
62	our $VERSION = '0.8';	79	our $VERSION = '3.31';
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::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]
104		191
		192	=item $loop->loop ([$flags])
		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::loop_done.	195	callback calls EV::unloop.
107		196
108	The $flags argument can be one of the following:	197	The $flags argument can be one of the following:
109		198
110	0 as above	199	0 as above
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	200	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	201	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		202
114	=item EV::loop_done [$how]	203	=item EV::unloop [$how]
115		204
		205	=item $loop->unloop ([$how])
		206
116	When called with no arguments or an argument of 1, makes the innermost	207	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	call to EV::loop return.	208	innermost call to EV::loop return.
118		209
119	When called with an agrument of 2, 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. "Roughly" because the time of	478	seconds, and then every C<$repeat> seconds. The timer does his best not
264	callback processing is not taken into account, so the timer will slowly	479	to drift, but it will not invoke the timer more often then once per event
265	drift. If that isn't acceptable, look at EV::periodic.	480	loop iteration, and might drift in other cases. If that isn't acceptable,
		481	look at EV::periodic, which can provide long-term stable timers.
266		482
267	The timer is based on a monotonic clock, that is if somebody is sitting	483	The timer is based on a monotonic clock, that is, if somebody is sitting
268	in front of the machine while the timer is running and changes the system	484	in front of the machine while the timer is running and changes the system
269	clock, the timer will nevertheless run (roughly) the same time.	485	clock, the timer will nevertheless run (roughly) the same time.
270		486
271	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.
272		488
273	=item $w->set ($after, $repeat)	489	=item $w->set ($after, $repeat)
274		490
275	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
276	any time.	492	any time.
277		493
278	=item $w->again	494	=item $w->again
279		495
280	Similar to the C<start> method, but has special semantics for repeating timers:	496	Similar to the C<start> method, but has special semantics for repeating timers:
		497
		498	If the timer is active and non-repeating, it will be stopped.
281		499
282	If the timer is active and repeating, reset the timeout to occur	500	If the timer is active and repeating, reset the timeout to occur
283	C<$repeat> seconds after now.	501	C<$repeat> seconds after now.
284		502
285	If the timer is active and non-repeating, it will be stopped.
286
287	If the timer is in active and repeating, start it.	503	If the timer is inactive and repeating, start it using the repeat value.
288		504
289	Otherwise do nothing.	505	Otherwise do nothing.
290		506
291	This behaviour is useful when you have a timeout for some IO	507	This behaviour is useful when you have a timeout for some IO
292	operation. You create a timer object with the same value for C<$after> and	508	operation. You create a timer object with the same value for C<$after> and
293	C<$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
294	on the timeout.	510	on the timeout.
295		511
		512	=back
		513
		514
		515	=head3 PERIODIC WATCHERS - to cron or not to cron?
		516
		517	=over 4
296		518
297	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	519	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
298		520
299	=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, $callback)
300		526
301	Similar to EV::timer, but is not based on relative timeouts but on	527	Similar to EV::timer, but is not based on relative timeouts but on
302	absolute times. Apart from creating "simple" timers that trigger "at" the	528	absolute times. Apart from creating "simple" timers that trigger "at" the
303	specified time, it can also be used for non-drifting absolute timers and	529	specified time, it can also be used for non-drifting absolute timers and
304	more complex, cron-like, setups that are not adversely affected by time	530	more complex, cron-like, setups that are not adversely affected by time
…		…
314	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	540	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
315	will not adjust when a time jump occurs, that is, if it is to be run	541	will not adjust when a time jump occurs, that is, if it is to be run
316	at January 1st 2011 then it will run when the system time reaches or	542	at January 1st 2011 then it will run when the system time reaches or
317	surpasses this time.	543	surpasses this time.
318		544
319	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	545	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
320		546
321	In this mode the watcher will always be scheduled to time out at the	547	In this mode the watcher will always be scheduled to time out at the
322	next C<$at + N * $interval> time (for some integer N) and then repeat,	548	next C<$at + N * $interval> time (for some integer N) and then repeat,
323	regardless of any time jumps.	549	regardless of any time jumps.
324		550
…		…
336	possible time where C<$time = $at (mod $interval)>, regardless of any time	562	possible time where C<$time = $at (mod $interval)>, regardless of any time
337	jumps.	563	jumps.
338		564
339	=item * manual reschedule mode ($reschedule_cb = coderef)	565	=item * manual reschedule mode ($reschedule_cb = coderef)
340		566
341	In this mode $interval and $at are both being ignored. Instead, each time	567	In this mode $interval and $at are both being ignored. Instead, each
342	the periodic watcher gets scheduled, the first callback ($reschedule_cb)	568	time the periodic watcher gets scheduled, the reschedule callback
343	will be called with the watcher as first, and the current time as second	569	($reschedule_cb) will be called with the watcher as first, and the current
344	argument.	570	time as second argument.
345		571
346	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
347	watcher, ever>. If you need to stop it, return 1e30 and stop it	573	watcher, ever>. If you need to stop it, return 1e30 and stop it
348	afterwards.	574	afterwards.
349		575
…		…
372		598
373	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	599	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
374		600
375	=item $w->set ($at, $interval, $reschedule_cb)	601	=item $w->set ($at, $interval, $reschedule_cb)
376		602
377	Reconfigures the watcher, see the constructor above for details. Can be at	603	Reconfigures the watcher, see the constructor above for details. Can be called at
378	any time.	604	any time.
379		605
380	=item $w->again	606	=item $w->again
381		607
382	Simply stops and starts the watcher again.	608	Simply stops and starts the watcher again.
383		609
		610	=item $time = $w->at
		611
		612	Return the time that the watcher is expected to trigger next.
		613
		614	=back
		615
		616
		617	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		618
		619	=over 4
384		620
385	=item $w = EV::signal $signal, $callback	621	=item $w = EV::signal $signal, $callback
386		622
387	=item $w = EV::signal_ns $signal, $callback	623	=item $w = EV::signal_ns $signal, $callback
388		624
389	Call the callback when $signal is received (the signal can be specified	625	Call the callback when $signal is received (the signal can be specified by
390	by number or by name, just as with kill or %SIG).	626	number or by name, just as with C<kill> or C<%SIG>).
391		627
392	EV will grab the signal for the process (the kernel only allows one	628	EV will grab the signal for the process (the kernel only allows one
393	component to receive a signal at a time) when you start a signal watcher,	629	component to receive a signal at a time) when you start a signal watcher,
394	and removes it again when you stop it. Perl does the same when you	630	and removes it again when you stop it. Perl does the same when you
395	add/remove callbacks to %SIG, so watch out.	631	add/remove callbacks to C<%SIG>, so watch out.
396		632
397	You can have as many signal watchers per signal as you want.	633	You can have as many signal watchers per signal as you want.
398		634
399	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	635	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
400		636
401	=item $w->set ($signal)	637	=item $w->set ($signal)
402		638
403	Reconfigures the watcher, see the constructor above for details. Can be at	639	Reconfigures the watcher, see the constructor above for details. Can be
404	any time.	640	called at any time.
405		641
406	=item $current_signum = $w->signal	642	=item $current_signum = $w->signal
407		643
408	=item $old_signum = $w->signal ($new_signal)	644	=item $old_signum = $w->signal ($new_signal)
409		645
410	Returns the previously set signal (always as a number not name) and	646	Returns the previously set signal (always as a number not name) and
411	optionally set a new one.	647	optionally set a new one.
412		648
		649	=back
413		650
		651
		652	=head3 CHILD WATCHERS - watch out for process status changes
		653
		654	=over 4
		655
414	=item $w = EV::child $pid, $callback	656	=item $w = EV::child $pid, $trace, $callback
415		657
416	=item $w = EV::child_ns $pid, $callback	658	=item $w = EV::child_ns $pid, $trace, $callback
		659
		660	=item $w = $loop->child ($pid, $trace, $callback)
		661
		662	=item $w = $loop->child_ns ($pid, $trace, $callback)
417		663
418	Call the callback when a status change for pid C<$pid> (or any pid	664	Call the callback when a status change for pid C<$pid> (or any pid
419	if C<$pid> is 0) has been received. More precisely: when the process	665	if C<$pid> is 0) has been received (a status change happens when the
		666	process terminates or is killed, or, when trace is true, additionally when
		667	it is stopped or continued). More precisely: when the process receives
420	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	668	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
421	changed/zombie children and call the callback.	669	changed/zombie children and call the callback.
422		670
423	You can access both status and pid by using the C<rstatus> and C<rpid>	671	It is valid (and fully supported) to install a child watcher after a child
424	methods on the watcher object.	672	has exited but before the event loop has started its next iteration (for
		673	example, first you C<fork>, then the new child process might exit, and
		674	only then do you install a child watcher in the parent for the new pid).
425		675
		676	You can access both exit (or tracing) status and pid by using the
		677	C<rstatus> and C<rpid> methods on the watcher object.
		678
426	You can have as many pid watchers per pid as you want.	679	You can have as many pid watchers per pid as you want, they will all be
		680	called.
427		681
428	The C<child_ns> variant doesn't start (activate) the newly created watcher.	682	The C<child_ns> variant doesn't start (activate) the newly created watcher.
429		683
430	=item $w->set ($pid)	684	=item $w->set ($pid, $trace)
431		685
432	Reconfigures the watcher, see the constructor above for details. Can be at	686	Reconfigures the watcher, see the constructor above for details. Can be called at
433	any time.	687	any time.
434		688
435	=item $current_pid = $w->pid	689	=item $current_pid = $w->pid
436
437	=item $old_pid = $w->pid ($new_pid)
438		690
439	Returns the previously set process id and optionally set a new one.	691	Returns the previously set process id and optionally set a new one.
440		692
441	=item $exit_status = $w->rstatus	693	=item $exit_status = $w->rstatus
442		694
…		…
446	=item $pid = $w->rpid	698	=item $pid = $w->rpid
447		699
448	Return the pid of the awaited child (useful when you have installed a	700	Return the pid of the awaited child (useful when you have installed a
449	watcher for all pids).	701	watcher for all pids).
450		702
		703	=back
		704
		705
		706	=head3 STAT WATCHERS - did the file attributes just change?
		707
		708	=over 4
		709
		710	=item $w = EV::stat $path, $interval, $callback
		711
		712	=item $w = EV::stat_ns $path, $interval, $callback
		713
		714	=item $w = $loop->stat ($path, $interval, $callback)
		715
		716	=item $w = $loop->stat_ns ($path, $interval, $callback)
		717
		718	Call the callback when a file status change has been detected on
		719	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		720	to "path does not exist" is a status change like any other.
		721
		722	The C<$interval> is a recommended polling interval for systems where
		723	OS-supported change notifications don't exist or are not supported. If
		724	you use C<0> then an unspecified default is used (which is highly
		725	recommended!), which is to be expected to be around five seconds usually.
		726
		727	This watcher type is not meant for massive numbers of stat watchers,
		728	as even with OS-supported change notifications, this can be
		729	resource-intensive.
		730
		731	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		732
		733	=item ... = $w->stat
		734
		735	This call is very similar to the perl C<stat> built-in: It stats (using
		736	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		737	well as EV's idea of the current stat values) to the values found.
		738
		739	In scalar context, a boolean is return indicating success or failure of
		740	the stat. In list context, the same 13-value list as with stat is returned
		741	(except that the blksize and blocks fields are not reliable).
		742
		743	In the case of an error, errno is set to C<ENOENT> (regardless of the
		744	actual error value) and the C<nlink> value is forced to zero (if the stat
		745	was successful then nlink is guaranteed to be non-zero).
		746
		747	See also the next two entries for more info.
		748
		749	=item ... = $w->attr
		750
		751	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		752	the values most recently detected by EV. See the next entry for more info.
		753
		754	=item ... = $w->prev
		755
		756	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		757	the previous set of values, before the change.
		758
		759	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		760	to the values found I<before> a change was detected, while C<< $w->attr >>
		761	returns the values found leading to the change detection. The difference (if any)
		762	between C<prev> and C<attr> is what triggered the callback.
		763
		764	If you did something to the filesystem object and do not want to trigger
		765	yet another change, you can call C<stat> to update EV's idea of what the
		766	current attributes are.
		767
		768	=item $w->set ($path, $interval)
		769
		770	Reconfigures the watcher, see the constructor above for details. Can be
		771	called at any time.
		772
		773	=item $current_path = $w->path
		774
		775	=item $old_path = $w->path ($new_path)
		776
		777	Returns the previously set path and optionally set a new one.
		778
		779	=item $current_interval = $w->interval
		780
		781	=item $old_interval = $w->interval ($new_interval)
		782
		783	Returns the previously set interval and optionally set a new one. Can be
		784	used to query the actual interval used.
		785
		786	=back
		787
		788
		789	=head3 IDLE WATCHERS - when you've got nothing better to do...
		790
		791	=over 4
451		792
452	=item $w = EV::idle $callback	793	=item $w = EV::idle $callback
453		794
454	=item $w = EV::idle_ns $callback	795	=item $w = EV::idle_ns $callback
455		796
456	Call the callback when there are no pending io, timer/periodic, signal or	797	=item $w = $loop->idle ($callback)
457	child events, i.e. when the process is idle.	798
		799	=item $w = $loop->idle_ns ($callback)
		800
		801	Call the callback when there are no other pending watchers of the same or
		802	higher priority (excluding check, prepare and other idle watchers of the
		803	same or lower priority, of course). They are called idle watchers because
		804	when the watcher is the highest priority pending event in the process, the
		805	process is considered to be idle at that priority.
		806
		807	If you want a watcher that is only ever called when I<no> other events are
		808	outstanding you have to set the priority to C<EV::MINPRI>.
458		809
459	The process will not block as long as any idle watchers are active, and	810	The process will not block as long as any idle watchers are active, and
460	they will be called repeatedly until stopped.	811	they will be called repeatedly until stopped.
461		812
		813	For example, if you have idle watchers at priority C<0> and C<1>, and
		814	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		815	and the I/O watcher will always run when ready. Only when the idle watcher
		816	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		817	pending with the C<0>-priority idle watcher be invoked.
		818
462	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	819	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
463		820
		821	=back
		822
		823
		824	=head3 PREPARE WATCHERS - customise your event loop!
		825
		826	=over 4
464		827
465	=item $w = EV::prepare $callback	828	=item $w = EV::prepare $callback
466		829
467	=item $w = EV::prepare_ns $callback	830	=item $w = EV::prepare_ns $callback
		831
		832	=item $w = $loop->prepare ($callback)
		833
		834	=item $w = $loop->prepare_ns ($callback)
468		835
469	Call the callback just before the process would block. You can still	836	Call the callback just before the process would block. You can still
470	create/modify any watchers at this point.	837	create/modify any watchers at this point.
471		838
472	See the EV::check watcher, below, for explanations and an example.	839	See the EV::check watcher, below, for explanations and an example.
473		840
474	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	841	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
475		842
		843	=back
		844
		845
		846	=head3 CHECK WATCHERS - customise your event loop even more!
		847
		848	=over 4
476		849
477	=item $w = EV::check $callback	850	=item $w = EV::check $callback
478		851
479	=item $w = EV::check_ns $callback	852	=item $w = EV::check_ns $callback
		853
		854	=item $w = $loop->check ($callback)
		855
		856	=item $w = $loop->check_ns ($callback)
480		857
481	Call the callback just after the process wakes up again (after it has	858	Call the callback just after the process wakes up again (after it has
482	gathered events), but before any other callbacks have been invoked.	859	gathered events), but before any other callbacks have been invoked.
483		860
484	This is used to integrate other event-based software into the EV	861	This is used to integrate other event-based software into the EV
…		…
492	# do nothing unless active	869	# do nothing unless active
493	$dispatcher->{_event_queue_h}	870	$dispatcher->{_event_queue_h}
494	or return;	871	or return;
495		872
496	# make the dispatcher handle any outstanding stuff	873	# make the dispatcher handle any outstanding stuff
		874	... not shown
497		875
498	# create an IO watcher for each and every socket	876	# create an I/O watcher for each and every socket
499	@snmp_watcher = (	877	@snmp_watcher = (
500	(map { EV::io $_, EV::READ, sub { } }	878	(map { EV::io $_, EV::READ, sub { } }
501	keys %{ $dispatcher->{_descriptors} }),	879	keys %{ $dispatcher->{_descriptors} }),
		880
		881	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		882	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		883	0, sub { },
502	);	884	);
503
504	# if there are any timeouts, also create a timer
505	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
506	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
507	};	885	};
508		886
509	The callbacks are irrelevant, the only purpose of those watchers is	887	The callbacks are irrelevant (and are not even being called), the
510	to wake up the process as soon as one of those events occurs (socket	888	only purpose of those watchers is to wake up the process as soon as
511	readable, or timer timed out). The corresponding EV::check watcher will then	889	one of those events occurs (socket readable, or timer timed out). The
512	clean up:	890	corresponding EV::check watcher will then clean up:
513		891
514	our $snmp_check = EV::check sub {	892	our $snmp_check = EV::check sub {
515	# destroy all watchers	893	# destroy all watchers
516	@snmp_watcher = ();	894	@snmp_watcher = ();
517		895
518	# make the dispatcher handle any new stuff	896	# make the dispatcher handle any new stuff
		897	... not shown
519	};	898	};
520		899
521	The callbacks of the created watchers will not be called as the watchers	900	The callbacks of the created watchers will not be called as the watchers
522	are destroyed before this cna happen (remember EV::check gets called	901	are destroyed before this cna happen (remember EV::check gets called
523	first).	902	first).
524		903
525	The C<check_ns> variant doesn't start (activate) the newly created watcher.	904	The C<check_ns> variant doesn't start (activate) the newly created watcher.
526		905
527	=back	906	=back
528		907
		908
		909	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		910
		911	Fork watchers are called when a C<fork ()> was detected. The invocation
		912	is done before the event loop blocks next and before C<check> watchers
		913	are being called, and only in the child after the fork.
		914
		915	=over 4
		916
		917	=item $w = EV::fork $callback
		918
		919	=item $w = EV::fork_ns $callback
		920
		921	=item $w = $loop->fork ($callback)
		922
		923	=item $w = $loop->fork_ns ($callback)
		924
		925	Call the callback before the event loop is resumed in the child process
		926	after a fork.
		927
		928	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		929
		930	=back
		931
		932
		933	=head3 EMBED WATCHERS - when one backend isn't enough...
		934
		935	This is a rather advanced watcher type that lets you embed one event loop
		936	into another (currently only IO events are supported in the embedded
		937	loop, other types of watchers might be handled in a delayed or incorrect
		938	fashion and must not be used).
		939
		940	See the libev documentation at
		941	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		942	for more details.
		943
		944	In short, this watcher is most useful on BSD systems without working
		945	kqueue to still be able to handle a large number of sockets:
		946
		947	my $socket_loop;
		948
		949	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		950	if (
		951	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		952	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		953	) {
		954	# use kqueue for sockets
		955	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		956	}
		957
		958	# use the default loop otherwise
		959	$socket_loop \|\|= EV::default_loop;
		960
		961	=over 4
		962
		963	=item $w = EV::embed $otherloop, $callback
		964
		965	=item $w = EV::embed_ns $otherloop, $callback
		966
		967	=item $w = $loop->embed ($otherloop, $callback)
		968
		969	=item $w = $loop->embed_ns ($otherloop, $callback)
		970
		971	Call the callback when the embedded event loop (C<$otherloop>) has any
		972	I/O activity. The C<$callback> should alwas be specified as C<undef> in
		973	this version of EV, which means the embedded event loop will be managed
		974	automatically.
		975
		976	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		977
		978	=back
		979
		980	=head3 ASYNC WATCHERS - how to wake up another event loop
		981
		982	Async watchers are provided by EV, but have little use in perl directly, as perl
		983	neither supports threads nor direct access to signal handlers or other
		984	contexts where they could be of value.
		985
		986	It is, however, possible to use them from the XS level.
		987
		988	Please see the libev documentation for further details.
		989
		990	=over 4
		991
		992	=item $w = EV::async $callback
		993
		994	=item $w = EV::async_ns $callback
		995
		996	=item $w->send
		997
		998	=item $bool = $w->async_pending
		999
		1000	=back
		1001
		1002
		1003	=head1 PERL SIGNALS
		1004
		1005	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1006	with EV is as the same as any other C library: Perl-signals will only be
		1007	handled when Perl runs, which means your signal handler might be invoked
		1008	only the next time an event callback is invoked.
		1009
		1010	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1011	ensure proper operations with regards to other event watchers.
		1012
		1013	If you cannot do this for whatever reason, you can also force a watcher
		1014	to be called on every event loop iteration by installing a C<EV::check>
		1015	watcher:
		1016
		1017	my $async_check = EV::check sub { };
		1018
		1019	This ensures that perl gets into control for a short time to handle any
		1020	pending signals, and also ensures (slightly) slower overall operation.
		1021
529	=head1 THREADS	1022	=head1 THREADS
530		1023
531	Threads are not supported by this in any way. Perl pseudo-threads is evil	1024	Threads are not supported by this module in any way. Perl pseudo-threads
532	stuff and must die.	1025	is evil stuff and must die. As soon as Perl gains real threads I will work
		1026	on thread support for it.
		1027
		1028	=head1 FORK
		1029
		1030	Most of the "improved" event delivering mechanisms of modern operating
		1031	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1032	not supported and usually destructive). Libev makes it possible to work
		1033	around this by having a function that recreates the kernel state after
		1034	fork in the child.
		1035
		1036	On non-win32 platforms, this module requires the pthread_atfork
		1037	functionality to do this automatically for you. This function is quite
		1038	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1039	negligible, because everything the function currently does is set a flag
		1040	that is checked only when the event loop gets used the next time, so when
		1041	you do fork but not use EV, the overhead is minimal.
		1042
		1043	On win32, there is no notion of fork so all this doesn't apply, of course.
533		1044
534	=cut	1045	=cut
535		1046
536	our $DIED = sub {	1047	our $DIED = sub {
537	warn "EV: error in callback (ignoring): $@";	1048	warn "EV: error in callback (ignoring): $@";
538	};	1049	};
539		1050
540	default_loop	1051	default_loop
541	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1052	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
542		1053
543	1;	1054	1;
544		1055
545	=head1 SEE ALSO	1056	=head1 SEE ALSO
546		1057
547	L<EV::DNS>, L<EV::AnyEvent>.	1058	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1059	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1060	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1061	event-loop agnostic and portable event driven programming.
548		1062
549	=head1 AUTHOR	1063	=head1 AUTHOR
550		1064
551	Marc Lehmann <schmorp@schmorp.de>	1065	Marc Lehmann <schmorp@schmorp.de>
552	http://home.schmorp.de/	1066	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.36 by root, Sun Nov 11 04:14:09 2007 UTC vs. Revision 1.91 by root, Tue May 6 12:43:58 2008 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.36 by root, Sun Nov 11 04:14:09 2007 UTC vs.
Revision 1.91 by root, Tue May 6 12:43:58 2008 UTC