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

Comparing EV/EV.pm (file contents):
Revision 1.27 by root, Sat Nov 3 09:19:58 2007 UTC vs.
Revision 1.61 by root, Thu Dec 6 03:13:07 2007 UTC

…		…
10		10
11	my $w = EV::timer 2, 0, sub {	11	my $w = EV::timer 2, 0, sub {
12	warn "is called after 2s";	12	warn "is called after 2s";
13	};	13	};
14		14
15	my $w = EV::timer 2, 1, sub {	15	my $w = EV::timer 2, 2, sub {
16	warn "is called roughly every 2s (repeat = 1)";	16	warn "is called roughly every 2s (repeat = 2)";
17	};	17	};
18		18
19	undef $w; # destroy event watcher again	19	undef $w; # destroy event watcher again
20		20
21	my $w = EV::periodic 0, 60, sub {	21	my $w = EV::periodic 0, 60, 0, sub {
22	warn "is called every minute, on the minute, exactly";	22	warn "is called every minute, on the minute, exactly";
23	};	23	};
24		24
25	# IO	25	# IO
26		26
27	my $w = EV::io *STDIN, EV::READ, sub {	27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $revents) = @_; # all callbacks get the watcher object and event mask	28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29	warn "stdin is readable, you entered: ", <STDIN>;	29	warn "stdin is readable, you entered: ", <STDIN>;
30	};	30	};
31		31
32	# SIGNALS	32	# SIGNALS
33		33
34	my $w = EV::signal 'QUIT', sub {	34	my $w = EV::signal 'QUIT', sub {
35	warn "sigquit received\n";	35	warn "sigquit received\n";
36	};	36	};
37		37
38	my $w = EV::signal 3, sub {
39	warn "sigquit received (this is GNU/Linux, right?)\n";
40	};
41
42	# CHILD/PID STATUS CHANGES	38	# CHILD/PID STATUS CHANGES
43		39
44	my $w = EV::child 666, sub {	40	my $w = EV::child 666, sub {
45	my ($w, $revents) = @_;	41	my ($w, $revents) = @_;
46	# my $pid = $w->rpid;
47	my $status = $w->rstatus;	42	my $status = $w->rstatus;
48	};	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	};
49		50
50	# MAINLOOP	51	# MAINLOOP
51	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
52	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
53	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
54		55
55	=head1 DESCRIPTION	56	=head1 DESCRIPTION
56		57
57	This module provides an interface to libev	58	This module provides an interface to libev
58	(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>.
59		64
60	=cut	65	=cut
61		66
62	package EV;	67	package EV;
63		68
64	use strict;	69	use strict;
65		70
66	BEGIN {	71	BEGIN {
67	our $VERSION = '0.5';	72	our $VERSION = '1.6';
68	use XSLoader;	73	use XSLoader;
69	XSLoader::load "EV", $VERSION;	74	XSLoader::load "EV", $VERSION;
70	}	75	}
71		76
72	@EV::Io::ISA =	77	@EV::IO::ISA =
73	@EV::Timer::ISA =	78	@EV::Timer::ISA =
74	@EV::Periodic::ISA =	79	@EV::Periodic::ISA =
75	@EV::Signal::ISA =	80	@EV::Signal::ISA =
		81	@EV::Child::ISA =
		82	@EV::Stat::ISA =
76	@EV::Idle::ISA =	83	@EV::Idle::ISA =
77	@EV::Prepare::ISA =	84	@EV::Prepare::ISA =
78	@EV::Check::ISA =	85	@EV::Check::ISA =
79	@EV::Child::ISA = "EV::Watcher";	86	@EV::Embed::ISA =
		87	@EV::Fork::ISA =
		88	"EV::Watcher";
80		89
81	=head1 BASIC INTERFACE	90	=head1 BASIC INTERFACE
82		91
83	=over 4	92	=over 4
84		93
…		…
98		107
99	Returns the time the last event loop iteration has been started. This	108	Returns the time the last event loop iteration has been started. This
100	is the time that (relative) timers are based on, and refering to it is	109	is the time that (relative) timers are based on, and refering to it is
101	usually faster then calling EV::time.	110	usually faster then calling EV::time.
102		111
103	=item $method = EV::ev_method	112	=item $method = EV::method
104		113
105	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	114	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
106	or EV::METHOD_EPOLL).	115	or EV::METHOD_EPOLL).
107		116
108	=item EV::loop [$flags]	117	=item EV::loop [$flags]
109		118
110	Begin checking for events and calling callbacks. It returns when a	119	Begin checking for events and calling callbacks. It returns when a
111	callback calls EV::loop_done.	120	callback calls EV::unloop.
112		121
113	The $flags argument can be one of the following:	122	The $flags argument can be one of the following:
114		123
115	0 as above	124	0 as above
116	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	125	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
117	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	126	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
118		127
119	=item EV::loop_done [$how]	128	=item EV::unloop [$how]
120		129
121	When called with no arguments or an argument of 1, makes the innermost	130	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
122	call to EV::loop return.	131	innermost call to EV::loop return.
123		132
124	When called with an agrument of 2, all calls to EV::loop will return as	133	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
125	fast as possible.	134	fast as possible.
126		135
127	=back	136	=item $count = EV::loop_count
128		137
		138	Return the number of times the event loop has polled for new
		139	events. Sometiems useful as a generation counter.
		140
		141	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		142
		143	This function rolls together an I/O and a timer watcher for a single
		144	one-shot event without the need for managing a watcher object.
		145
		146	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		147	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		148	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		149	you do not want to wait for some I/O event, specify C<undef> for
		150	C<$fh_or_undef> and C<0> for C<$events>).
		151
		152	If timeout is C<undef> or negative, then there will be no
		153	timeout. Otherwise a EV::timer with this value will be started.
		154
		155	When an error occurs or either the timeout or I/O watcher triggers, then
		156	the callback will be called with the received event set (in general
		157	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		158	C<EV::WRITE> and C<EV::TIMEOUT>).
		159
		160	EV::once doesn't return anything: the watchers stay active till either
		161	of them triggers, then they will be stopped and freed, and the callback
		162	invoked.
		163
		164	=back
		165
129	=head2 WATCHER	166	=head2 WATCHER OBJECTS
130		167
131	A watcher is an object that gets created to record your interest in some	168	A watcher is an object that gets created to record your interest in some
132	event. For instance, if you want to wait for STDIN to become readable, you	169	event. For instance, if you want to wait for STDIN to become readable, you
133	would create an EV::io watcher for that:	170	would create an EV::io watcher for that:
134		171
…		…
159		196
160	Also, all methods changing some aspect of a watcher (->set, ->priority,	197	Also, all methods changing some aspect of a watcher (->set, ->priority,
161	->fh and so on) automatically stop and start it again if it is active,	198	->fh and so on) automatically stop and start it again if it is active,
162	which means pending events get lost.	199	which means pending events get lost.
163		200
164	=head2 WATCHER TYPES	201	=head2 COMMON WATCHER METHODS
165		202
166	Now lets move to the existing watcher types and asociated methods.	203	This section lists methods common to all watchers.
167
168	The following methods are available for all watchers. Then followes a
169	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
170	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
171	any type-specific methods (if any).
172		204
173	=over 4	205	=over 4
174		206
175	=item $w->start	207	=item $w->start
176		208
…		…
185	regardless of wether the watcher was active or not.	217	regardless of wether the watcher was active or not.
186		218
187	=item $bool = $w->is_active	219	=item $bool = $w->is_active
188		220
189	Returns true if the watcher is active, false otherwise.	221	Returns true if the watcher is active, false otherwise.
		222
		223	=item $current_data = $w->data
		224
		225	=item $old_data = $w->data ($new_data)
		226
		227	Queries a freely usable data scalar on the watcher and optionally changes
		228	it. This is a way to associate custom data with a watcher:
		229
		230	my $w = EV::timer 60, 0, sub {
		231	warn $_[0]->data;
		232	};
		233	$w->data ("print me!");
190		234
191	=item $current_cb = $w->cb	235	=item $current_cb = $w->cb
192		236
193	=item $old_cb = $w->cb ($new_cb)	237	=item $old_cb = $w->cb ($new_cb)
194		238
…		…
203	watchers with higher priority will be invoked first. The valid range of	247	watchers with higher priority will be invoked first. The valid range of
204	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	248	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
205	-2). If the priority is outside this range it will automatically be	249	-2). If the priority is outside this range it will automatically be
206	normalised to the nearest valid priority.	250	normalised to the nearest valid priority.
207		251
208	The default priority of any newly-created weatcher is 0.	252	The default priority of any newly-created watcher is 0.
		253
		254	Note that the priority semantics have not yet been fleshed out and are
		255	subject to almost certain change.
209		256
210	=item $w->trigger ($revents)	257	=item $w->trigger ($revents)
211		258
212	Call the callback now with the given event mask.	259	Call the callback now with the given event mask.
213		260
		261	=item $previous_state = $w->keepalive ($bool)
		262
		263	Normally, C<EV::loop> will return when there are no active watchers
		264	(which is a "deadlock" because no progress can be made anymore). This is
		265	convinient because it allows you to start your watchers (and your jobs),
		266	call C<EV::loop> once and when it returns you know that all your jobs are
		267	finished (or they forgot to register some watchers for their task :).
		268
		269	Sometimes, however, this gets in your way, for example when you the module
		270	that calls C<EV::loop> (usually the main program) is not the same module
		271	as a long-living watcher (for example a DNS client module written by
		272	somebody else even). Then you might want any outstanding requests to be
		273	handled, but you would not want to keep C<EV::loop> from returning just
		274	because you happen to have this long-running UDP port watcher.
		275
		276	In this case you can clear the keepalive status, which means that even
		277	though your watcher is active, it won't keep C<EV::loop> from returning.
		278
		279	The initial value for keepalive is true (enabled), and you cna change it
		280	any time.
		281
		282	Example: Register an IO watcher for some UDP socket but do not keep the
		283	event loop from running just because of that watcher.
		284
		285	my $udp_socket = ...
		286	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		287	$udp_watcher->keepalive (0);
		288
		289	=back
		290
		291
		292	=head2 WATCHER TYPES
		293
		294	Each of the following subsections describes a single watcher type.
		295
		296	=head3 IO WATCHERS - is this file descriptor readable or writable?
		297
		298	=over 4
214		299
215	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	300	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
216		301
217	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	302	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
218		303
219	As long as the returned watcher object is alive, call the C<$callback>	304	As long as the returned watcher object is alive, call the C<$callback>
220	when the events specified in C<$eventmask>.	305	when at least one of events specified in C<$eventmask> occurs.
221		306
222	The $eventmask can be one or more of these constants ORed together:	307	The $eventmask can be one or more of these constants ORed together:
223		308
224	EV::READ wait until read() wouldn't block anymore	309	EV::READ wait until read() wouldn't block anymore
225	EV::WRITE wait until write() wouldn't block anymore	310	EV::WRITE wait until write() wouldn't block anymore
…		…
241		326
242	=item $old_eventmask = $w->events ($new_eventmask)	327	=item $old_eventmask = $w->events ($new_eventmask)
243		328
244	Returns the previously set event mask and optionally set a new one.	329	Returns the previously set event mask and optionally set a new one.
245		330
		331	=back
		332
		333
		334	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		335
		336	=over 4
246		337
247	=item $w = EV::timer $after, $repeat, $callback	338	=item $w = EV::timer $after, $repeat, $callback
248		339
249	=item $w = EV::timer_ns $after, $repeat, $callback	340	=item $w = EV::timer_ns $after, $repeat, $callback
250		341
251	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	342	Calls the callback after C<$after> seconds (which may be fractional). If
252	the timer will be restarted (with the $repeat value as $after) after the	343	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
253	callback returns.	344	value as $after) after the callback returns.
254		345
255	This means that the callback would be called roughly after C<$after>	346	This means that the callback would be called roughly after C<$after>
256	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	347	seconds, and then every C<$repeat> seconds. The timer does his best not
257	callback processing is not taken into account, so the timer will slowly	348	to drift, but it will not invoke the timer more often then once per event
258	drift. If that isn't acceptable, look at EV::periodic.	349	loop iteration, and might drift in other cases. If that isn't acceptable,
		350	look at EV::periodic, which can provide long-term stable timers.
259		351
260	The timer is based on a monotonic clock, that is if somebody is sitting	352	The timer is based on a monotonic clock, that is, if somebody is sitting
261	in front of the machine while the timer is running and changes the system	353	in front of the machine while the timer is running and changes the system
262	clock, the timer will nevertheless run (roughly) the same time.	354	clock, the timer will nevertheless run (roughly) the same time.
263		355
264	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	356	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
265		357
266	=item $w->set ($after, $repeat)	358	=item $w->set ($after, $repeat)
267		359
268	Reconfigures the watcher, see the constructor above for details. Can be at	360	Reconfigures the watcher, see the constructor above for details. Can be called at
269	any time.	361	any time.
270		362
271	=item $w->again	363	=item $w->again
272		364
273	Similar to the C<start> method, but has special semantics for repeating timers:	365	Similar to the C<start> method, but has special semantics for repeating timers:
		366
		367	If the timer is active and non-repeating, it will be stopped.
274		368
275	If the timer is active and repeating, reset the timeout to occur	369	If the timer is active and repeating, reset the timeout to occur
276	C<$repeat> seconds after now.	370	C<$repeat> seconds after now.
277		371
278	If the timer is active and non-repeating, it will be stopped.
279
280	If the timer is in active and repeating, start it.	372	If the timer is inactive and repeating, start it using the repeat value.
281		373
282	Otherwise do nothing.	374	Otherwise do nothing.
283		375
284	This behaviour is useful when you have a timeout for some IO	376	This behaviour is useful when you have a timeout for some IO
285	operation. You create a timer object with the same value for C<$after> and	377	operation. You create a timer object with the same value for C<$after> and
286	C<$repeat>, and then, in the read/write watcher, run the C<again> method	378	C<$repeat>, and then, in the read/write watcher, run the C<again> method
287	on the timeout.	379	on the timeout.
288		380
		381	=back
289		382
		383
		384	=head3 PERIODIC WATCHERS - to cron or not to cron?
		385
		386	=over 4
		387
290	=item $w = EV::periodic $at, $interval, $callback	388	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
291		389
292	=item $w = EV::periodic_ns $at, $interval, $callback	390	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
293		391
294	Similar to EV::timer, but the time is given as an absolute point in time	392	Similar to EV::timer, but is not based on relative timeouts but on
295	(C<$at>), plus an optional C<$interval>.	393	absolute times. Apart from creating "simple" timers that trigger "at" the
		394	specified time, it can also be used for non-drifting absolute timers and
		395	more complex, cron-like, setups that are not adversely affected by time
		396	jumps (i.e. when the system clock is changed by explicit date -s or other
		397	means such as ntpd). It is also the most complex watcher type in EV.
296		398
297	If the C<$interval> is zero, then the callback will be called at the time	399	It has three distinct "modes":
298	C<$at> if that is in the future, or as soon as possible if it is in the
299	past. It will not automatically repeat.
300		400
301	If the C<$interval> is nonzero, then the watcher will always be scheduled	401	=over 4
302	to time out at the next C<$at + N * $interval> time.
303		402
304	This can be used to schedule a callback to run at very regular intervals,	403	=item * absolute timer ($interval = $reschedule_cb = 0)
305	as long as the processing time is less then the interval (otherwise	404
306	obviously events will be skipped).	405	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		406	will not adjust when a time jump occurs, that is, if it is to be run
		407	at January 1st 2011 then it will run when the system time reaches or
		408	surpasses this time.
		409
		410	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		411
		412	In this mode the watcher will always be scheduled to time out at the
		413	next C<$at + N * $interval> time (for some integer N) and then repeat,
		414	regardless of any time jumps.
		415
		416	This can be used to create timers that do not drift with respect to system
		417	time:
		418
		419	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		420
		421	That doesn't mean there will always be 3600 seconds in between triggers,
		422	but only that the the clalback will be called when the system time shows a
		423	full hour (UTC).
307		424
308	Another way to think about it (for the mathematically inclined) is that	425	Another way to think about it (for the mathematically inclined) is that
309	EV::periodic will try to run the callback at the next possible time where	426	EV::periodic will try to run the callback in this mode at the next
310	C<$time = $at (mod $interval)>, regardless of any time jumps.	427	possible time where C<$time = $at (mod $interval)>, regardless of any time
		428	jumps.
311		429
312	This periodic timer is based on "wallclock time", that is, if the clock	430	=item * manual reschedule mode ($reschedule_cb = coderef)
313	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	431
314	the specified time. This means it will never drift (it might jitter, but	432	In this mode $interval and $at are both being ignored. Instead, each
315	it will not drift).	433	time the periodic watcher gets scheduled, the reschedule callback
		434	($reschedule_cb) will be called with the watcher as first, and the current
		435	time as second argument.
		436
		437	I<This callback MUST NOT stop or destroy this or any other periodic
		438	watcher, ever>. If you need to stop it, return 1e30 and stop it
		439	afterwards.
		440
		441	It must return the next time to trigger, based on the passed time value
		442	(that is, the lowest time value larger than to the second argument). It
		443	will usually be called just before the callback will be triggered, but
		444	might be called at other times, too.
		445
		446	This can be used to create very complex timers, such as a timer that
		447	triggers on each midnight, local time (actually 24 hours after the last
		448	midnight, to keep the example simple. If you know a way to do it correctly
		449	in about the same space (without requiring elaborate modules), drop me a
		450	note :):
		451
		452	my $daily = EV::periodic 0, 0, sub {
		453	my ($w, $now) = @_;
		454
		455	use Time::Local ();
		456	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		457	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		458	}, sub {
		459	print "it's midnight or likely shortly after, now\n";
		460	};
		461
		462	=back
316		463
317	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	464	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
318		465
319	=item $w->set ($at, $interval)	466	=item $w->set ($at, $interval, $reschedule_cb)
320		467
321	Reconfigures the watcher, see the constructor above for details. Can be at	468	Reconfigures the watcher, see the constructor above for details. Can be called at
322	any time.	469	any time.
323		470
		471	=item $w->again
		472
		473	Simply stops and starts the watcher again.
		474
		475	=back
		476
		477
		478	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		479
		480	=over 4
324		481
325	=item $w = EV::signal $signal, $callback	482	=item $w = EV::signal $signal, $callback
326		483
327	=item $w = EV::signal_ns $signal, $callback	484	=item $w = EV::signal_ns $signal, $callback
328		485
329	Call the callback when $signal is received (the signal can be specified	486	Call the callback when $signal is received (the signal can be specified by
330	by number or by name, just as with kill or %SIG).	487	number or by name, just as with C<kill> or C<%SIG>).
331		488
332	EV will grab the signal for the process (the kernel only allows one	489	EV will grab the signal for the process (the kernel only allows one
333	component to receive a signal at a time) when you start a signal watcher,	490	component to receive a signal at a time) when you start a signal watcher,
334	and removes it again when you stop it. Perl does the same when you	491	and removes it again when you stop it. Perl does the same when you
335	add/remove callbacks to %SIG, so watch out.	492	add/remove callbacks to C<%SIG>, so watch out.
336		493
337	You can have as many signal watchers per signal as you want.	494	You can have as many signal watchers per signal as you want.
338		495
339	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	496	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
340		497
341	=item $w->set ($signal)	498	=item $w->set ($signal)
342		499
343	Reconfigures the watcher, see the constructor above for details. Can be at	500	Reconfigures the watcher, see the constructor above for details. Can be
344	any time.	501	called at any time.
345		502
346	=item $current_signum = $w->signal	503	=item $current_signum = $w->signal
347		504
348	=item $old_signum = $w->signal ($new_signal)	505	=item $old_signum = $w->signal ($new_signal)
349		506
350	Returns the previously set signal (always as a number not name) and	507	Returns the previously set signal (always as a number not name) and
351	optionally set a new one.	508	optionally set a new one.
352		509
		510	=back
		511
		512
		513	=head3 CHILD WATCHERS - watch out for process status changes
		514
		515	=over 4
353		516
354	=item $w = EV::child $pid, $callback	517	=item $w = EV::child $pid, $callback
355		518
356	=item $w = EV::child_ns $pid, $callback	519	=item $w = EV::child_ns $pid, $callback
357		520
358	Call the callback when a status change for pid C<$pid> (or any pid	521	Call the callback when a status change for pid C<$pid> (or any pid if
359	if C<$pid> is 0) has been received. More precisely: when the process	522	C<$pid> is 0) has been received. More precisely: when the process receives
360	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	523	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
361	changed/zombie children and call the callback.	524	changed/zombie children and call the callback.
362		525
363	You can access both status and pid by using the C<rstatus> and C<rpid>	526	It is valid (and fully supported) to install a child watcher after a child
364	methods on the watcher object.	527	has exited but before the event loop has started its next iteration (for
		528	example, first you C<fork>, then the new child process might exit, and
		529	only then do you install a child watcher in the parent for the new pid).
365		530
		531	You can access both exit (or tracing) status and pid by using the
		532	C<rstatus> and C<rpid> methods on the watcher object.
		533
366	You can have as many pid watchers per pid as you want.	534	You can have as many pid watchers per pid as you want, they will all be
		535	called.
367		536
368	The C<child_ns> variant doesn't start (activate) the newly created watcher.	537	The C<child_ns> variant doesn't start (activate) the newly created watcher.
369		538
370	=item $w->set ($pid)	539	=item $w->set ($pid)
371		540
372	Reconfigures the watcher, see the constructor above for details. Can be at	541	Reconfigures the watcher, see the constructor above for details. Can be called at
373	any time.	542	any time.
374		543
375	=item $current_pid = $w->pid	544	=item $current_pid = $w->pid
376		545
377	=item $old_pid = $w->pid ($new_pid)	546	=item $old_pid = $w->pid ($new_pid)
…		…
386	=item $pid = $w->rpid	555	=item $pid = $w->rpid
387		556
388	Return the pid of the awaited child (useful when you have installed a	557	Return the pid of the awaited child (useful when you have installed a
389	watcher for all pids).	558	watcher for all pids).
390		559
		560	=back
		561
		562
		563	=head3 STAT WATCHERS - did the file attributes just change?
		564
		565	=over 4
		566
		567	=item $w = EV::stat $path, $interval, $callback
		568
		569	=item $w = EV::stat_ns $path, $interval, $callback
		570
		571	Call the callback when a file status change has been detected on
		572	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		573	to "path does not exist" is a status change like any other.
		574
		575	The C<$interval> is a recommended polling interval for systems where
		576	OS-supported change notifications don't exist or are not supported. If
		577	you use C<0> then an unspecified default is used (which is highly
		578	recommended!), which is to be expected to be around five seconds usually.
		579
		580	This watcher type is not meant for massive numbers of stat watchers,
		581	as even with OS-supported change notifications, this can be
		582	resource-intensive.
		583
		584	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		585
		586	=item ... = $w->stat
		587
		588	This call is very similar to the perl C<stat> built-in: It stats (using
		589	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		590	well as EV's idea of the current stat values) to the values found.
		591
		592	In scalar context, a boolean is return indicating success or failure of
		593	the stat. In list context, the same 13-value list as with stat is returned
		594	(except that the blksize and blocks fields are not reliable).
		595
		596	In the case of an error, errno is set to C<ENOENT> (regardless of the
		597	actual error value) and the C<nlink> value is forced to zero (if the stat
		598	was successful then nlink is guaranteed to be non-zero).
		599
		600	See also the next two entries for more info.
		601
		602	=item ... = $w->attr
		603
		604	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		605	the values most recently detected by EV. See the next entry for more info.
		606
		607	=item ... = $w->prev
		608
		609	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		610	the previous set of values, before the change.
		611
		612	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		613	to the values found I<before> a change was detected, while C<< $w->attr >>
		614	returns the values found leading to the change detection. The difference (if any)
		615	between C<prev> and C<attr> is what triggered the callback.
		616
		617	If you did something to the filesystem object and do not want to trigger
		618	yet another change, you can call C<stat> to update EV's idea of what the
		619	current attributes are.
		620
		621	=item $w->set ($path, $interval)
		622
		623	Reconfigures the watcher, see the constructor above for details. Can be
		624	called at any time.
		625
		626	=item $current_path = $w->path
		627
		628	=item $old_path = $w->path ($new_path)
		629
		630	Returns the previously set path and optionally set a new one.
		631
		632	=item $current_interval = $w->interval
		633
		634	=item $old_interval = $w->interval ($new_interval)
		635
		636	Returns the previously set interval and optionally set a new one. Can be
		637	used to query the actual interval used.
		638
		639	=back
		640
		641
		642	=head3 IDLE WATCHERS - when you've got nothing better to do...
		643
		644	=over 4
391		645
392	=item $w = EV::idle $callback	646	=item $w = EV::idle $callback
393		647
394	=item $w = EV::idle_ns $callback	648	=item $w = EV::idle_ns $callback
395		649
…		…
399	The process will not block as long as any idle watchers are active, and	653	The process will not block as long as any idle watchers are active, and
400	they will be called repeatedly until stopped.	654	they will be called repeatedly until stopped.
401		655
402	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	656	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
403		657
		658	=back
		659
		660
		661	=head3 PREPARE WATCHERS - customise your event loop!
		662
		663	=over 4
404		664
405	=item $w = EV::prepare $callback	665	=item $w = EV::prepare $callback
406		666
407	=item $w = EV::prepare_ns $callback	667	=item $w = EV::prepare_ns $callback
408		668
…		…
411		671
412	See the EV::check watcher, below, for explanations and an example.	672	See the EV::check watcher, below, for explanations and an example.
413		673
414	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	674	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
415		675
		676	=back
		677
		678
		679	=head3 CHECK WATCHERS - customise your event loop even more!
		680
		681	=over 4
416		682
417	=item $w = EV::check $callback	683	=item $w = EV::check $callback
418		684
419	=item $w = EV::check_ns $callback	685	=item $w = EV::check_ns $callback
420		686
…		…
432	# do nothing unless active	698	# do nothing unless active
433	$dispatcher->{_event_queue_h}	699	$dispatcher->{_event_queue_h}
434	or return;	700	or return;
435		701
436	# make the dispatcher handle any outstanding stuff	702	# make the dispatcher handle any outstanding stuff
		703	... not shown
437		704
438	# create an IO watcher for each and every socket	705	# create an IO watcher for each and every socket
439	@snmp_watcher = (	706	@snmp_watcher = (
440	(map { EV::io $_, EV::READ, sub { } }	707	(map { EV::io $_, EV::READ, sub { } }
441	keys %{ $dispatcher->{_descriptors} }),	708	keys %{ $dispatcher->{_descriptors} }),
		709
		710	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		711	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		712	0, sub { },
442	);	713	);
443
444	# if there are any timeouts, also create a timer
445	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
446	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
447	};	714	};
448		715
449	The callbacks are irrelevant, the only purpose of those watchers is	716	The callbacks are irrelevant (and are not even being called), the
450	to wake up the process as soon as one of those events occurs (socket	717	only purpose of those watchers is to wake up the process as soon as
451	readable, or timer timed out). The corresponding EV::check watcher will then	718	one of those events occurs (socket readable, or timer timed out). The
452	clean up:	719	corresponding EV::check watcher will then clean up:
453		720
454	our $snmp_check = EV::check sub {	721	our $snmp_check = EV::check sub {
455	# destroy all watchers	722	# destroy all watchers
456	@snmp_watcher = ();	723	@snmp_watcher = ();
457		724
458	# make the dispatcher handle any new stuff	725	# make the dispatcher handle any new stuff
		726	... not shown
459	};	727	};
460		728
461	The callbacks of the created watchers will not be called as the watchers	729	The callbacks of the created watchers will not be called as the watchers
462	are destroyed before this cna happen (remember EV::check gets called	730	are destroyed before this cna happen (remember EV::check gets called
463	first).	731	first).
464		732
465	The C<check_ns> variant doesn't start (activate) the newly created watcher.	733	The C<check_ns> variant doesn't start (activate) the newly created watcher.
466		734
467	=back	735	=back
468		736
		737
		738	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		739
		740	Fork watchers are called when a C<fork ()> was detected. The invocation
		741	is done before the event loop blocks next and before C<check> watchers
		742	are being called, and only in the child after the fork.
		743
		744	=over 4
		745
		746	=item $w = EV::fork $callback
		747
		748	=item $w = EV::fork_ns $callback
		749
		750	Call the callback before the event loop is resumed in the child process
		751	after a fork.
		752
		753	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		754
		755	=back
		756
		757
		758	=head1 PERL SIGNALS
		759
		760	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		761	with EV is as the same as any other C library: Perl-signals will only be
		762	handled when Perl runs, which means your signal handler might be invoked
		763	only the next time an event callback is invoked.
		764
		765	The solution is to use EV signal watchers (see C<EV::signal>), which will
		766	ensure proper operations with regards to other event watchers.
		767
		768	If you cannot do this for whatever reason, you can also force a watcher
		769	to be called on every event loop iteration by installing a C<EV::check>
		770	watcher:
		771
		772	my $async_check = EV::check sub { };
		773
		774	This ensures that perl shortly gets into control for a short time, and
		775	also ensures slower overall operation.
		776
469	=head1 THREADS	777	=head1 THREADS
470		778
471	Threads are not supported by this in any way. Perl pseudo-threads is evil	779	Threads are not supported by this module in any way. Perl pseudo-threads
472	stuff and must die.	780	is evil stuff and must die. As soon as Perl gains real threads I will work
		781	on thread support for it.
		782
		783	=head1 FORK
		784
		785	Most of the "improved" event delivering mechanisms of modern operating
		786	systems have quite a few problems with fork(2) (to put it bluntly: it is
		787	not supported and usually destructive). Libev makes it possible to work
		788	around this by having a function that recreates the kernel state after
		789	fork in the child.
		790
		791	On non-win32 platforms, this module requires the pthread_atfork
		792	functionality to do this automatically for you. This function is quite
		793	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		794	negligible, because everything the function currently does is set a flag
		795	that is checked only when the event loop gets used the next time, so when
		796	you do fork but not use EV, the overhead is minimal.
		797
		798	On win32, there is no notion of fork so all this doesn't apply, of course.
473		799
474	=cut	800	=cut
475		801
476	our $DIED = sub {	802	our $DIED = sub {
477	warn "EV: error in callback (ignoring): $@";	803	warn "EV: error in callback (ignoring): $@";
478	};	804	};
479		805
480	init	806	default_loop
481	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	807	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
482		808
483	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
484
485	1;	809	1;
486		810
487	=head1 SEE ALSO	811	=head1 SEE ALSO
488		812
489	L<EV::DNS>, L<EV::AnyEvent>.	813	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		814	event loop), L<Coro::EV> (efficient coroutines with EV).
490		815
491	=head1 AUTHOR	816	=head1 AUTHOR
492		817
493	Marc Lehmann <schmorp@schmorp.de>	818	Marc Lehmann <schmorp@schmorp.de>
494	http://home.schmorp.de/	819	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.27 by root, Sat Nov 3 09:19:58 2007 UTC vs. Revision 1.61 by root, Thu Dec 6 03:13:07 2007 UTC

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Revision 1.27 by root, Sat Nov 3 09:19:58 2007 UTC vs.
Revision 1.61 by root, Thu Dec 6 03:13:07 2007 UTC