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

Comparing EV/EV.pm (file contents):
Revision 1.40 by root, Fri Nov 16 05:04:36 2007 UTC vs.
Revision 1.75 by root, Fri Dec 21 10:36:22 2007 UTC

…		…
39		39
40	my $w = EV::child 666, sub {	40	my $w = EV::child 666, sub {
41	my ($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::unloop is called or all watchers stop	52	EV::loop; # loop until EV::unloop is called or all watchers stop
47	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
48	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
49		55
50	=head1 DESCRIPTION	56	=head1 DESCRIPTION
51		57
52	This module provides an interface to libev	58	This module provides an interface to libev
53	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of libev
		61	itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on
		62	watcher semantics or some discussion on the available backends, or how to
		63	force a specific backend with C<LIBEV_FLAGS>, or just about in any case
		64	because it has much more detailed information.
54		65
55	=cut	66	=cut
56		67
57	package EV;	68	package EV;
58		69
59	use strict;	70	use strict;
60		71
61	BEGIN {	72	BEGIN {
62	our $VERSION = '0.9';	73	our $VERSION = '2.0';
63	use XSLoader;	74	use XSLoader;
64	XSLoader::load "EV", $VERSION;	75	XSLoader::load "EV", $VERSION;
65	}	76	}
66		77
67	@EV::Io::ISA =	78	@EV::IO::ISA =
68	@EV::Timer::ISA =	79	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	80	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	81	@EV::Signal::ISA =
		82	@EV::Child::ISA =
		83	@EV::Stat::ISA =
71	@EV::Idle::ISA =	84	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	85	@EV::Prepare::ISA =
73	@EV::Check::ISA =	86	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	87	@EV::Embed::ISA =
		88	@EV::Fork::ISA =
		89	"EV::Watcher";
		90
		91	@EV::Loop::Default::ISA = "EV::Loop";
		92
		93	=head1 EVENT LOOPS
		94
		95	EV supports multiple event loops: There is a single "default event loop"
		96	that can handle everything including signals and child watchers, and any
		97	number of "dynamic event loops" that can use different backends (with
		98	various limitations), but no child and signal watchers.
		99
		100	You do not have to do anything to create the default event loop: When
		101	the module is loaded a suitable backend is selected on the premise of
		102	selecting a working backend (which for example rules out kqueue on most
		103	BSDs). Modules should, unless they have "special needs" always use the
		104	default loop as this is fastest (perl-wise), best supported by other
		105	modules (e.g. AnyEvent or Coro) and most portable event loop.
		106
		107	For specific programs you cna create additional event loops dynamically.
		108
		109	=over 4
		110
		111	=item $loop = new EV::loop [$flags]
		112
		113	Create a new event loop as per the specified flags. Please refer to the
		114	C<ev_loop_new ()> function description in the libev documentation
		115	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		116	for more info.
		117
		118	The loop will automatically be destroyed when it is no longer referenced
		119	by any watcher and the loop object goes out of scope.
		120
		121	Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
		122	is protected by this module.
		123
		124	=item $loop->loop_fork
		125
		126	Must be called after a fork in the child, before entering or continuing
		127	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		128	this fucntion automatically, at some performance loss (refer to the libev
		129	documentation).
		130
		131	=back
		132
75		133
76	=head1 BASIC INTERFACE	134	=head1 BASIC INTERFACE
77		135
78	=over 4	136	=over 4
79		137
80	=item $EV::DIED	138	=item $EV::DIED
81		139
82	Must contain a reference to a function that is called when a callback	140	Must contain a reference to a function that is called when a callback
83	throws an exception (with $@ containing thr error). The default prints an	141	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	142	informative message and continues.
85		143
86	If this callback throws an exception it will be silently ignored.	144	If this callback throws an exception it will be silently ignored.
87		145
88	=item $time = EV::time	146	=item $time = EV::time
89		147
90	Returns the current time in (fractional) seconds since the epoch.	148	Returns the current time in (fractional) seconds since the epoch.
91		149
92	=item $time = EV::now	150	=item $time = EV::now
		151
		152	=item $time = $loop->now
93		153
94	Returns the time the last event loop iteration has been started. This	154	Returns the time the last event loop iteration has been started. This
95	is the time that (relative) timers are based on, and refering to it is	155	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	156	usually faster then calling EV::time.
97		157
98	=item $method = EV::ev_method	158	=item $backend = EV::backend
		159
		160	=item $backend = $loop->backend
99		161
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	162	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	163	or EV::METHOD_EPOLL).
102		164
103	=item EV::loop [$flags]	165	=item EV::loop [$flags]
		166
		167	=item $loop->loop ([$flags])
104		168
105	Begin checking for events and calling callbacks. It returns when a	169	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	170	callback calls EV::unloop.
107		171
108	The $flags argument can be one of the following:	172	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	175	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	176	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		177
114	=item EV::unloop [$how]	178	=item EV::unloop [$how]
115		179
		180	=item $loop->unloop ([$how])
		181
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	182	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	183	innermost call to EV::loop return.
118		184
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	185	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	186	fast as possible.
121		187
122	=back	188	=item $count = EV::loop_count
123		189
124	=head2 WATCHER	190	=item $count = $loop->loop_count
		191
		192	Return the number of times the event loop has polled for new
		193	events. Sometiems useful as a generation counter.
		194
		195	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		196
		197	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		198
		199	This function rolls together an I/O and a timer watcher for a single
		200	one-shot event without the need for managing a watcher object.
		201
		202	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		203	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		204	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		205	you do not want to wait for some I/O event, specify C<undef> for
		206	C<$fh_or_undef> and C<0> for C<$events>).
		207
		208	If timeout is C<undef> or negative, then there will be no
		209	timeout. Otherwise a EV::timer with this value will be started.
		210
		211	When an error occurs or either the timeout or I/O watcher triggers, then
		212	the callback will be called with the received event set (in general
		213	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		214	C<EV::WRITE> and C<EV::TIMEOUT>).
		215
		216	EV::once doesn't return anything: the watchers stay active till either
		217	of them triggers, then they will be stopped and freed, and the callback
		218	invoked.
		219
		220	=item EV::feed_fd_event ($fd, $revents)
		221
		222	=item $loop->feed_fd_event ($fd, $revents)
		223
		224	Feed an event on a file descriptor into EV. EV will react to this call as
		225	if the readyness notifications specified by C<$revents> (a combination of
		226	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		227
		228	=item EV::feed_signal_event ($signal)
		229
		230	Feed a signal event into EV. EV will react to this call as if the signal
		231	specified by C<$signal> had occured.
		232
		233	=back
		234
		235
		236	=head1 WATCHER OBJECTS
125		237
126	A watcher is an object that gets created to record your interest in some	238	A watcher is an object that gets created to record your interest in some
127	event. For instance, if you want to wait for STDIN to become readable, you	239	event. For instance, if you want to wait for STDIN to become readable, you
128	would create an EV::io watcher for that:	240	would create an EV::io watcher for that:
129		241
…		…
138	events.	250	events.
139		251
140	Each watcher type has its associated bit in revents, so you can use the	252	Each watcher type has its associated bit in revents, so you can use the
141	same callback for multiple watchers. The event mask is named after the	253	same callback for multiple watchers. The event mask is named after the
142	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	254	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
143	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	255	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
144	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	256	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
145	uses EV::TIMEOUT).	257	uses EV::TIMEOUT).
146		258
147	In the rare case where one wants to create a watcher but not start it at	259	In the rare case where one wants to create a watcher but not start it at
148	the same time, each constructor has a variant with a trailing C<_ns> in	260	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
154		266
155	Also, all methods changing some aspect of a watcher (->set, ->priority,	267	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,	268	->fh and so on) automatically stop and start it again if it is active,
157	which means pending events get lost.	269	which means pending events get lost.
158		270
159	=head2 WATCHER TYPES	271	=head2 COMMON WATCHER METHODS
160		272
161	Now lets move to the existing watcher types and asociated methods.	273	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		274
168	=over 4	275	=over 4
169		276
170	=item $w->start	277	=item $w->start
171		278
…		…
175		282
176	=item $w->stop	283	=item $w->stop
177		284
178	Stop a watcher if it is active. Also clear any pending events (events that	285	Stop a watcher if it is active. Also clear any pending events (events that
179	have been received but that didn't yet result in a callback invocation),	286	have been received but that didn't yet result in a callback invocation),
180	regardless of wether the watcher was active or not.	287	regardless of whether the watcher was active or not.
181		288
182	=item $bool = $w->is_active	289	=item $bool = $w->is_active
183		290
184	Returns true if the watcher is active, false otherwise.	291	Returns true if the watcher is active, false otherwise.
185		292
…		…
210	watchers with higher priority will be invoked first. The valid range of	317	watchers with higher priority will be invoked first. The valid range of
211	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	318	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
212	-2). If the priority is outside this range it will automatically be	319	-2). If the priority is outside this range it will automatically be
213	normalised to the nearest valid priority.	320	normalised to the nearest valid priority.
214		321
215	The default priority of any newly-created weatcher is 0.	322	The default priority of any newly-created watcher is 0.
216		323
		324	Note that the priority semantics have not yet been fleshed out and are
		325	subject to almost certain change.
		326
217	=item $w->trigger ($revents)	327	=item $w->invoke ($revents)
218		328
219	Call the callback now with the given event mask.	329	Call the callback now with the given event mask.
220		330
		331	=item $w->feed_event ($revents)
		332
		333	Feed some events on this watcher into EV. EV will react to this call as if
		334	the watcher had received the given C<$revents> mask.
		335
		336	=item $revents = $w->clear_pending
		337
		338	If the watcher is pending, this function returns clears its pending status
		339	and returns its C<$revents> bitset (as if its callback was invoked). If the
		340	watcher isn't pending it does nothing and returns C<0>.
		341
		342	=item $previous_state = $w->keepalive ($bool)
		343
		344	Normally, C<EV::loop> will return when there are no active watchers
		345	(which is a "deadlock" because no progress can be made anymore). This is
		346	convinient because it allows you to start your watchers (and your jobs),
		347	call C<EV::loop> once and when it returns you know that all your jobs are
		348	finished (or they forgot to register some watchers for their task :).
		349
		350	Sometimes, however, this gets in your way, for example when you the module
		351	that calls C<EV::loop> (usually the main program) is not the same module
		352	as a long-living watcher (for example a DNS client module written by
		353	somebody else even). Then you might want any outstanding requests to be
		354	handled, but you would not want to keep C<EV::loop> from returning just
		355	because you happen to have this long-running UDP port watcher.
		356
		357	In this case you can clear the keepalive status, which means that even
		358	though your watcher is active, it won't keep C<EV::loop> from returning.
		359
		360	The initial value for keepalive is true (enabled), and you cna change it
		361	any time.
		362
		363	Example: Register an I/O watcher for some UDP socket but do not keep the
		364	event loop from running just because of that watcher.
		365
		366	my $udp_socket = ...
		367	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		368	$1000udp_watcher->keepalive (0);
		369
		370	=item $loop = $w->loop
		371
		372	Return the loop that this watcher is attached to.
		373
		374	=back
		375
		376
		377	=head1 WATCHER TYPES
		378
		379	Each of the following subsections describes a single watcher type.
		380
		381	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		382
		383	=over 4
221		384
222	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	385	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
223		386
224	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	387	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
225		388
		389	=item $w = $loop->io 8$fileno_or_fh, $eventmask, $callback)
		390
		391	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		392
226	As long as the returned watcher object is alive, call the C<$callback>	393	As long as the returned watcher object is alive, call the C<$callback>
227	when the events specified in C<$eventmask>.	394	when at least one of events specified in C<$eventmask> occurs.
228		395
229	The $eventmask can be one or more of these constants ORed together:	396	The $eventmask can be one or more of these constants ORed together:
230		397
231	EV::READ wait until read() wouldn't block anymore	398	EV::READ wait until read() wouldn't block anymore
232	EV::WRITE wait until write() wouldn't block anymore	399	EV::WRITE wait until write() wouldn't block anymore
…		…
248		415
249	=item $old_eventmask = $w->events ($new_eventmask)	416	=item $old_eventmask = $w->events ($new_eventmask)
250		417
251	Returns the previously set event mask and optionally set a new one.	418	Returns the previously set event mask and optionally set a new one.
252		419
		420	=back
		421
		422
		423	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		424
		425	=over 4
253		426
254	=item $w = EV::timer $after, $repeat, $callback	427	=item $w = EV::timer $after, $repeat, $callback
255		428
256	=item $w = EV::timer_ns $after, $repeat, $callback	429	=item $w = EV::timer_ns $after, $repeat, $callback
257		430
258	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	431	=item $w = $loop->timer ($after, $repeat, $callback)
259	the timer will be restarted (with the $repeat value as $after) after the	432
260	callback returns.	433	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		434
		435	Calls the callback after C<$after> seconds (which may be fractional). If
		436	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		437	value as $after) after the callback returns.
261		438
262	This means that the callback would be called roughly after C<$after>	439	This means that the callback would be called roughly after C<$after>
263	seconds, and then every C<$repeat> seconds. The timer does his best not	440	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	441	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,	442	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
271		448
272	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	449	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
273		450
274	=item $w->set ($after, $repeat)	451	=item $w->set ($after, $repeat)
275		452
276	Reconfigures the watcher, see the constructor above for details. Can be at	453	Reconfigures the watcher, see the constructor above for details. Can be called at
277	any time.	454	any time.
278		455
279	=item $w->again	456	=item $w->again
280		457
281	Similar to the C<start> method, but has special semantics for repeating timers:	458	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
292	This behaviour is useful when you have a timeout for some IO	469	This behaviour is useful when you have a timeout for some IO
293	operation. You create a timer object with the same value for C<$after> and	470	operation. You create a timer object with the same value for C<$after> and
294	C<$repeat>, and then, in the read/write watcher, run the C<again> method	471	C<$repeat>, and then, in the read/write watcher, run the C<again> method
295	on the timeout.	472	on the timeout.
296		473
		474	=back
		475
		476
		477	=head3 PERIODIC WATCHERS - to cron or not to cron?
		478
		479	=over 4
297		480
298	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	481	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
299		482
300	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	483	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		484
		485	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		486
		487	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
301		488
302	Similar to EV::timer, but is not based on relative timeouts but on	489	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	490	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	491	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	492	more complex, cron-like, setups that are not adversely affected by time
…		…
373		560
374	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	561	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
375		562
376	=item $w->set ($at, $interval, $reschedule_cb)	563	=item $w->set ($at, $interval, $reschedule_cb)
377		564
378	Reconfigures the watcher, see the constructor above for details. Can be at	565	Reconfigures the watcher, see the constructor above for details. Can be called at
379	any time.	566	any time.
380		567
381	=item $w->again	568	=item $w->again
382		569
383	Simply stops and starts the watcher again.	570	Simply stops and starts the watcher again.
384		571
		572	=item $time = $w->at
		573
		574	Return the time that the watcher is expected to trigger next.
		575
		576	=back
		577
		578
		579	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		580
		581	=over 4
385		582
386	=item $w = EV::signal $signal, $callback	583	=item $w = EV::signal $signal, $callback
387		584
388	=item $w = EV::signal_ns $signal, $callback	585	=item $w = EV::signal_ns $signal, $callback
389		586
390	Call the callback when $signal is received (the signal can be specified	587	Call the callback when $signal is received (the signal can be specified by
391	by number or by name, just as with kill or %SIG).	588	number or by name, just as with C<kill> or C<%SIG>).
392		589
393	EV will grab the signal for the process (the kernel only allows one	590	EV will grab the signal for the process (the kernel only allows one
394	component to receive a signal at a time) when you start a signal watcher,	591	component to receive a signal at a time) when you start a signal watcher,
395	and removes it again when you stop it. Perl does the same when you	592	and removes it again when you stop it. Perl does the same when you
396	add/remove callbacks to %SIG, so watch out.	593	add/remove callbacks to C<%SIG>, so watch out.
397		594
398	You can have as many signal watchers per signal as you want.	595	You can have as many signal watchers per signal as you want.
399		596
400	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	597	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
401		598
402	=item $w->set ($signal)	599	=item $w->set ($signal)
403		600
404	Reconfigures the watcher, see the constructor above for details. Can be at	601	Reconfigures the watcher, see the constructor above for details. Can be
405	any time.	602	called at any time.
406		603
407	=item $current_signum = $w->signal	604	=item $current_signum = $w->signal
408		605
409	=item $old_signum = $w->signal ($new_signal)	606	=item $old_signum = $w->signal ($new_signal)
410		607
411	Returns the previously set signal (always as a number not name) and	608	Returns the previously set signal (always as a number not name) and
412	optionally set a new one.	609	optionally set a new one.
413		610
		611	=back
		612
		613
		614	=head3 CHILD WATCHERS - watch out for process status changes
		615
		616	=over 4
414		617
415	=item $w = EV::child $pid, $callback	618	=item $w = EV::child $pid, $callback
416		619
417	=item $w = EV::child_ns $pid, $callback	620	=item $w = EV::child_ns $pid, $callback
418		621
		622	=item $w = $loop->child ($pid, $callback)
		623
		624	=item $w = $loop->child_ns ($pid, $callback)
		625
419	Call the callback when a status change for pid C<$pid> (or any pid	626	Call the callback when a status change for pid C<$pid> (or any pid if
420	if C<$pid> is 0) has been received. More precisely: when the process	627	C<$pid> is 0) has been received. More precisely: when the process receives
421	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	628	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
422	changed/zombie children and call the callback.	629	changed/zombie children and call the callback.
423		630
424	You can access both status and pid by using the C<rstatus> and C<rpid>	631	It is valid (and fully supported) to install a child watcher after a child
425	methods on the watcher object.	632	has exited but before the event loop has started its next iteration (for
		633	example, first you C<fork>, then the new child process might exit, and
		634	only then do you install a child watcher in the parent for the new pid).
426		635
		636	You can access both exit (or tracing) status and pid by using the
		637	C<rstatus> and C<rpid> methods on the watcher object.
		638
427	You can have as many pid watchers per pid as you want.	639	You can have as many pid watchers per pid as you want, they will all be
		640	called.
428		641
429	The C<child_ns> variant doesn't start (activate) the newly created watcher.	642	The C<child_ns> variant doesn't start (activate) the newly created watcher.
430		643
431	=item $w->set ($pid)	644	=item $w->set ($pid)
432		645
433	Reconfigures the watcher, see the constructor above for details. Can be at	646	Reconfigures the watcher, see the constructor above for details. Can be called at
434	any time.	647	any time.
435		648
436	=item $current_pid = $w->pid	649	=item $current_pid = $w->pid
437		650
438	=item $old_pid = $w->pid ($new_pid)	651	=item $old_pid = $w->pid ($new_pid)
…		…
447	=item $pid = $w->rpid	660	=item $pid = $w->rpid
448		661
449	Return the pid of the awaited child (useful when you have installed a	662	Return the pid of the awaited child (useful when you have installed a
450	watcher for all pids).	663	watcher for all pids).
451		664
		665	=back
		666
		667
		668	=head3 STAT WATCHERS - did the file attributes just change?
		669
		670	=over 4
		671
		672	=item $w = EV::stat $path, $interval, $callback
		673
		674	=item $w = EV::stat_ns $path, $interval, $callback
		675
		676	=item $w = $loop->stat ($path, $interval, $callback)
		677
		678	=item $w = $loop->stat_ns ($path, $interval, $callback)
		679
		680	Call the callback when a file status change has been detected on
		681	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		682	to "path does not exist" is a status change like any other.
		683
		684	The C<$interval> is a recommended polling interval for systems where
		685	OS-supported change notifications don't exist or are not supported. If
		686	you use C<0> then an unspecified default is used (which is highly
		687	recommended!), which is to be expected to be around five seconds usually.
		688
		689	This watcher type is not meant for massive numbers of stat watchers,
		690	as even with OS-supported change notifications, this can be
		691	resource-intensive.
		692
		693	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		694
		695	=item ... = $w->stat
		696
		697	This call is very similar to the perl C<stat> built-in: It stats (using
		698	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		699	well as EV's idea of the current stat values) to the values found.
		700
		701	In scalar context, a boolean is return indicating success or failure of
		702	the stat. In list context, the same 13-value list as with stat is returned
		703	(except that the blksize and blocks fields are not reliable).
		704
		705	In the case of an error, errno is set to C<ENOENT> (regardless of the
		706	actual error value) and the C<nlink> value is forced to zero (if the stat
		707	was successful then nlink is guaranteed to be non-zero).
		708
		709	See also the next two entries for more info.
		710
		711	=item ... = $w->attr
		712
		713	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		714	the values most recently detected by EV. See the next entry for more info.
		715
		716	=item ... = $w->prev
		717
		718	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		719	the previous set of values, before the change.
		720
		721	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		722	to the values found I<before> a change was detected, while C<< $w->attr >>
		723	returns the values found leading to the change detection. The difference (if any)
		724	between C<prev> and C<attr> is what triggered the callback.
		725
		726	If you did something to the filesystem object and do not want to trigger
		727	yet another change, you can call C<stat> to update EV's idea of what the
		728	current attributes are.
		729
		730	=item $w->set ($path, $interval)
		731
		732	Reconfigures the watcher, see the constructor above for details. Can be
		733	called at any time.
		734
		735	=item $current_path = $w->path
		736
		737	=item $old_path = $w->path ($new_path)
		738
		739	Returns the previously set path and optionally set a new one.
		740
		741	=item $current_interval = $w->interval
		742
		743	=item $old_interval = $w->interval ($new_interval)
		744
		745	Returns the previously set interval and optionally set a new one. Can be
		746	used to query the actual interval used.
		747
		748	=back
		749
		750
		751	=head3 IDLE WATCHERS - when you've got nothing better to do...
		752
		753	=over 4
452		754
453	=item $w = EV::idle $callback	755	=item $w = EV::idle $callback
454		756
455	=item $w = EV::idle_ns $callback	757	=item $w = EV::idle_ns $callback
456		758
457	Call the callback when there are no pending io, timer/periodic, signal or	759	=item $w = $loop->idle ($callback)
458	child events, i.e. when the process is idle.	760
		761	=item $w = $loop->idle_ns ($callback)
		762
		763	Call the callback when there are no other pending watchers of the same or
		764	higher priority (excluding check, prepare and other idle watchers of the
		765	same or lower priority, of course). They are called idle watchers because
		766	when the watcher is the highest priority pending event in the process, the
		767	process is considered to be idle at that priority.
		768
		769	If you want a watcher that is only ever called when I<no> other events are
		770	outstanding you have to set the priority to C<EV::MINPRI>.
459		771
460	The process will not block as long as any idle watchers are active, and	772	The process will not block as long as any idle watchers are active, and
461	they will be called repeatedly until stopped.	773	they will be called repeatedly until stopped.
462		774
		775	For example, if you have idle watchers at priority C<0> and C<1>, and
		776	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		777	and the I/O watcher will always run when ready. Only when the idle watcher
		778	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		779	pending with the C<0>-priority idle watcher be invoked.
		780
463	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	781	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
464		782
		783	=back
		784
		785
		786	=head3 PREPARE WATCHERS - customise your event loop!
		787
		788	=over 4
465		789
466	=item $w = EV::prepare $callback	790	=item $w = EV::prepare $callback
467		791
468	=item $w = EV::prepare_ns $callback	792	=item $w = EV::prepare_ns $callback
		793
		794	=item $w = $loop->prepare ($callback)
		795
		796	=item $w = $loop->prepare_ns 8$callback)
469		797
470	Call the callback just before the process would block. You can still	798	Call the callback just before the process would block. You can still
471	create/modify any watchers at this point.	799	create/modify any watchers at this point.
472		800
473	See the EV::check watcher, below, for explanations and an example.	801	See the EV::check watcher, below, for explanations and an example.
474		802
475	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	803	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
476		804
		805	=back
		806
		807
		808	=head3 CHECK WATCHERS - customise your event loop even more!
		809
		810	=over 4
477		811
478	=item $w = EV::check $callback	812	=item $w = EV::check $callback
479		813
480	=item $w = EV::check_ns $callback	814	=item $w = EV::check_ns $callback
		815
		816	=item $w = $loop->check ($callback)
		817
		818	=item $w = $loop->check_ns ($callback)
481		819
482	Call the callback just after the process wakes up again (after it has	820	Call the callback just after the process wakes up again (after it has
483	gathered events), but before any other callbacks have been invoked.	821	gathered events), but before any other callbacks have been invoked.
484		822
485	This is used to integrate other event-based software into the EV	823	This is used to integrate other event-based software into the EV
…		…
493	# do nothing unless active	831	# do nothing unless active
494	$dispatcher->{_event_queue_h}	832	$dispatcher->{_event_queue_h}
495	or return;	833	or return;
496		834
497	# make the dispatcher handle any outstanding stuff	835	# make the dispatcher handle any outstanding stuff
		836	... not shown
498		837
499	# create an IO watcher for each and every socket	838	# create an I/O watcher for each and every socket
500	@snmp_watcher = (	839	@snmp_watcher = (
501	(map { EV::io $_, EV::READ, sub { } }	840	(map { EV::io $_, EV::READ, sub { } }
502	keys %{ $dispatcher->{_descriptors} }),	841	keys %{ $dispatcher->{_descriptors} }),
		842
		843	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		844	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		845	0, sub { },
503	);	846	);
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	};	847	};
509		848
510	The callbacks are irrelevant, the only purpose of those watchers is	849	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	850	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	851	one of those events occurs (socket readable, or timer timed out). The
513	clean up:	852	corresponding EV::check watcher will then clean up:
514		853
515	our $snmp_check = EV::check sub {	854	our $snmp_check = EV::check sub {
516	# destroy all watchers	855	# destroy all watchers
517	@snmp_watcher = ();	856	@snmp_watcher = ();
518		857
519	# make the dispatcher handle any new stuff	858	# make the dispatcher handle any new stuff
		859	... not shown
520	};	860	};
521		861
522	The callbacks of the created watchers will not be called as the watchers	862	The callbacks of the created watchers will not be called as the watchers
523	are destroyed before this cna happen (remember EV::check gets called	863	are destroyed before this cna happen (remember EV::check gets called
524	first).	864	first).
525		865
526	The C<check_ns> variant doesn't start (activate) the newly created watcher.	866	The C<check_ns> variant doesn't start (activate) the newly created watcher.
527		867
528	=back	868	=back
529		869
		870
		871	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		872
		873	Fork watchers are called when a C<fork ()> was detected. The invocation
		874	is done before the event loop blocks next and before C<check> watchers
		875	are being called, and only in the child after the fork.
		876
		877	=over 4
		878
		879	=item $w = EV::fork $callback
		880
		881	=item $w = EV::fork_ns $callback
		882
		883	=item $w = $loop->fork ($callback)
		884
		885	=item $w = $loop->fork_ns ($callback)
		886
		887	Call the callback before the event loop is resumed in the child process
		888	after a fork.
		889
		890	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		891
		892	=back
		893
		894
		895	=head1 PERL SIGNALS
		896
		897	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		898	with EV is as the same as any other C library: Perl-signals will only be
		899	handled when Perl runs, which means your signal handler might be invoked
		900	only the next time an event callback is invoked.
		901
		902	The solution is to use EV signal watchers (see C<EV::signal>), which will
		903	ensure proper operations with regards to other event watchers.
		904
		905	If you cannot do this for whatever reason, you can also force a watcher
		906	to be called on every event loop iteration by installing a C<EV::check>
		907	watcher:
		908
		909	my $async_check = EV::check sub { };
		910
		911	This ensures that perl gets into control for a short time to handle any
		912	pending signals, and also ensures (slightly) slower overall operation.
		913
530	=head1 THREADS	914	=head1 THREADS
531		915
532	Threads are not supported by this in any way. Perl pseudo-threads is evil	916	Threads are not supported by this module in any way. Perl pseudo-threads
533	stuff and must die.	917	is evil stuff and must die. As soon as Perl gains real threads I will work
		918	on thread support for it.
		919
		920	=head1 FORK
		921
		922	Most of the "improved" event delivering mechanisms of modern operating
		923	systems have quite a few problems with fork(2) (to put it bluntly: it is
		924	not supported and usually destructive). Libev makes it possible to work
		925	around this by having a function that recreates the kernel state after
		926	fork in the child.
		927
		928	On non-win32 platforms, this module requires the pthread_atfork
		929	functionality to do this automatically for you. This function is quite
		930	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		931	negligible, because everything the function currently does is set a flag
		932	that is checked only when the event loop gets used the next time, so when
		933	you do fork but not use EV, the overhead is minimal.
		934
		935	On win32, there is no notion of fork so all this doesn't apply, of course.
534		936
535	=cut	937	=cut
536		938
537	our $DIED = sub {	939	our $DIED = sub {
538	warn "EV: error in callback (ignoring): $@";	940	warn "EV: error in callback (ignoring): $@";
539	};	941	};
540		942
541	default_loop	943	default_loop
542	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	944	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
543		945
544	1;	946	1;
545		947
546	=head1 SEE ALSO	948	=head1 SEE ALSO
547		949
548	L<EV::DNS>.	950	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		951	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		952	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP).
549		953
550	=head1 AUTHOR	954	=head1 AUTHOR
551		955
552	Marc Lehmann <schmorp@schmorp.de>	956	Marc Lehmann <schmorp@schmorp.de>
553	http://home.schmorp.de/	957	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.40 by root, Fri Nov 16 05:04:36 2007 UTC vs. Revision 1.75 by root, Fri Dec 21 10:36:22 2007 UTC

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Revision 1.75 by root, Fri Dec 21 10:36:22 2007 UTC