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

Comparing EV/EV.pm (file contents):
Revision 1.22 by root, Fri Nov 2 11:02:22 2007 UTC vs.
Revision 1.57 by root, Wed Nov 28 17:32:24 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	# CHILD/PID STATUS CHANGES
		39
38	my $w = EV::signal 3, sub {	40	my $w = EV::child 666, sub {
39	warn "sigquit received (this is GNU/Linux, right?)\n";	41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
40	};	43	};
41		44
42	# CHILD/PID STATUS CHANGES	45	# STAT CHANGES
43		46	my $w = EV::stat "/etc/passwd", 10, sub {
44	my $w = EV::child 666, sub {
45	my ($w, $revents, $status) = @_;	47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
46	};	49	};
47		50
48	# MAINLOOP	51	# MAINLOOP
49	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
50	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
51	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
52		55
53	=head1 DESCRIPTION	56	=head1 DESCRIPTION
54		57
55	This module provides an interface to libev	58	This module provides an interface to libev
56	(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>.
57		64
58	=cut	65	=cut
59		66
60	package EV;	67	package EV;
61		68
62	use strict;	69	use strict;
63		70
64	BEGIN {	71	BEGIN {
65	our $VERSION = '0.1';	72	our $VERSION = '1.4';
66	use XSLoader;	73	use XSLoader;
67	XSLoader::load "EV", $VERSION;	74	XSLoader::load "EV", $VERSION;
68	}	75	}
69		76
70	@EV::Io::ISA =	77	@EV::IO::ISA =
71	@EV::Timer::ISA =	78	@EV::Timer::ISA =
72	@EV::Periodic::ISA =	79	@EV::Periodic::ISA =
73	@EV::Signal::ISA =	80	@EV::Signal::ISA =
		81	@EV::Child::ISA =
		82	@EV::Stat::ISA =
74	@EV::Idle::ISA =	83	@EV::Idle::ISA =
75	@EV::Prepare::ISA =	84	@EV::Prepare::ISA =
76	@EV::Check::ISA =	85	@EV::Check::ISA =
77	@EV::Child::ISA = "EV::Watcher";	86	@EV::Embed::ISA =
		87	@EV::Fork::ISA =
		88	"EV::Watcher";
78		89
79	=head1 BASIC INTERFACE	90	=head1 BASIC INTERFACE
80		91
81	=over 4	92	=over 4
82		93
…		…
96		107
97	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
98	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
99	usually faster then calling EV::time.	110	usually faster then calling EV::time.
100		111
101	=item $method = EV::ev_method	112	=item $method = EV::method
102		113
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	114	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
104	or EV::METHOD_EPOLL).	115	or EV::METHOD_EPOLL).
105		116
106	=item EV::loop [$flags]	117	=item EV::loop [$flags]
107		118
108	Begin checking for events and calling callbacks. It returns when a	119	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	120	callback calls EV::unloop.
110		121
111	The $flags argument can be one of the following:	122	The $flags argument can be one of the following:
112		123
113	0 as above	124	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	125	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	126	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		127
117	=item EV::loop_done [$how]	128	=item EV::unloop [$how]
118		129
119	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
120	call to EV::loop return.	131	innermost call to EV::loop return.
121		132
122	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
123	fast as possible.	134	fast as possible.
124		135
125	=back	136	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
126		137
		138	This function rolls together an I/O and a timer watcher for a single
		139	one-shot event without the need for managing a watcher object.
		140
		141	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		142	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		143	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		144	you do not want to wait for some I/O event, specify C<undef> for
		145	C<$fh_or_undef> and C<0> for C<$events>).
		146
		147	If timeout is C<undef> or negative, then there will be no
		148	timeout. Otherwise a EV::timer with this value will be started.
		149
		150	When an error occurs or either the timeout or I/O watcher triggers, then
		151	the callback will be called with the received event set (in general
		152	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		153	C<EV::WRITE> and C<EV::TIMEOUT>).
		154
		155	EV::once doesn't return anything: the watchers stay active till either
		156	of them triggers, then they will be stopped and freed, and the callback
		157	invoked.
		158
		159	=back
		160
127	=head2 WATCHER	161	=head2 WATCHER OBJECTS
128		162
129	A watcher is an object that gets created to record your interest in some	163	A watcher is an object that gets created to record your interest in some
130	event. For instance, if you want to wait for STDIN to become readable, you	164	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	165	would create an EV::io watcher for that:
132		166
…		…
150	In the rare case where one wants to create a watcher but not start it at	184	In the rare case where one wants to create a watcher but not start it at
151	the same time, each constructor has a variant with a trailing C<_ns> in	185	the same time, each constructor has a variant with a trailing C<_ns> in
152	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.	186	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
153		187
154	Please note that a watcher will automatically be stopped when the watcher	188	Please note that a watcher will automatically be stopped when the watcher
155	object is returned, so you I<need> to keep the watcher objects returned by	189	object is destroyed, so you I<need> to keep the watcher objects returned by
156	the constructors.	190	the constructors.
157		191
158	=head2 WATCHER TYPES	192	Also, all methods changing some aspect of a watcher (->set, ->priority,
		193	->fh and so on) automatically stop and start it again if it is active,
		194	which means pending events get lost.
159		195
160	Now lets move to the existing watcher types and asociated methods.	196	=head2 COMMON WATCHER METHODS
161		197
162	The following methods are available for all watchers. Then followes a	198	This section lists methods common to all watchers.
163	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
164	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
165	any type-specific methods (if any).
166		199
167	=over 4	200	=over 4
168		201
169	=item $w->start	202	=item $w->start
170		203
…		…
180		213
181	=item $bool = $w->is_active	214	=item $bool = $w->is_active
182		215
183	Returns true if the watcher is active, false otherwise.	216	Returns true if the watcher is active, false otherwise.
184		217
		218	=item $current_data = $w->data
		219
		220	=item $old_data = $w->data ($new_data)
		221
		222	Queries a freely usable data scalar on the watcher and optionally changes
		223	it. This is a way to associate custom data with a watcher:
		224
		225	my $w = EV::timer 60, 0, sub {
		226	warn $_[0]->data;
		227	};
		228	$w->data ("print me!");
		229
185	=item $current_cb = $w->cb	230	=item $current_cb = $w->cb
186		231
187	=item $old_cb = $w->cb ($new_cb)	232	=item $old_cb = $w->cb ($new_cb)
188		233
189	Queries the callback on the watcher and optionally changes it. You cna do	234	Queries the callback on the watcher and optionally changes it. You can do
190	this at any time.	235	this at any time without the watcher restarting.
		236
		237	=item $current_priority = $w->priority
		238
		239	=item $old_priority = $w->priority ($new_priority)
		240
		241	Queries the priority on the watcher and optionally changes it. Pending
		242	watchers with higher priority will be invoked first. The valid range of
		243	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		244	-2). If the priority is outside this range it will automatically be
		245	normalised to the nearest valid priority.
		246
		247	The default priority of any newly-created watcher is 0.
		248
		249	Note that the priority semantics have not yet been fleshed out and are
		250	subject to almost certain change.
191		251
192	=item $w->trigger ($revents)	252	=item $w->trigger ($revents)
193		253
194	Call the callback now with the given event mask.	254	Call the callback now with the given event mask.
195		255
		256	=item $previous_state = $w->keepalive ($bool)
		257
		258	Normally, C<EV::loop> will return when there are no active watchers
		259	(which is a "deadlock" because no progress can be made anymore). This is
		260	convinient because it allows you to start your watchers (and your jobs),
		261	call C<EV::loop> once and when it returns you know that all your jobs are
		262	finished (or they forgot to register some watchers for their task :).
		263
		264	Sometimes, however, this gets in your way, for example when you the module
		265	that calls C<EV::loop> (usually the main program) is not the same module
		266	as a long-living watcher (for example a DNS client module written by
		267	somebody else even). Then you might want any outstanding requests to be
		268	handled, but you would not want to keep C<EV::loop> from returning just
		269	because you happen to have this long-running UDP port watcher.
		270
		271	In this case you can clear the keepalive status, which means that even
		272	though your watcher is active, it won't keep C<EV::loop> from returning.
		273
		274	The initial value for keepalive is true (enabled), and you cna change it
		275	any time.
		276
		277	Example: Register an IO watcher for some UDP socket but do not keep the
		278	event loop from running just because of that watcher.
		279
		280	my $udp_socket = ...
		281	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		282	$udp_watcher->keepalive (0);
		283
		284	=back
		285
		286
		287	=head2 WATCHER TYPES
		288
		289	Each of the following subsections describes a single watcher type.
		290
		291	=head3 IO WATCHERS - is this file descriptor readable or writable?
		292
		293	=over 4
196		294
197	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	295	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
198		296
199	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	297	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
200		298
201	As long as the returned watcher object is alive, call the C<$callback>	299	As long as the returned watcher object is alive, call the C<$callback>
202	when the events specified in C<$eventmask>.	300	when at least one of events specified in C<$eventmask> occurs.
203		301
204	The $eventmask can be one or more of these constants ORed together:	302	The $eventmask can be one or more of these constants ORed together:
205		303
206	EV::READ wait until read() wouldn't block anymore	304	EV::READ wait until read() wouldn't block anymore
207	EV::WRITE wait until write() wouldn't block anymore	305	EV::WRITE wait until write() wouldn't block anymore
…		…
223		321
224	=item $old_eventmask = $w->events ($new_eventmask)	322	=item $old_eventmask = $w->events ($new_eventmask)
225		323
226	Returns the previously set event mask and optionally set a new one.	324	Returns the previously set event mask and optionally set a new one.
227		325
		326	=back
		327
		328
		329	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		330
		331	=over 4
228		332
229	=item $w = EV::timer $after, $repeat, $callback	333	=item $w = EV::timer $after, $repeat, $callback
230		334
231	=item $w = EV::timer_ns $after, $repeat, $callback	335	=item $w = EV::timer_ns $after, $repeat, $callback
232		336
233	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	337	Calls the callback after C<$after> seconds (which may be fractional). If
234	the timer will be restarted (with the $repeat value as $after) after the	338	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
235	callback returns.	339	value as $after) after the callback returns.
236		340
237	This means that the callback would be called roughly after C<$after>	341	This means that the callback would be called roughly after C<$after>
238	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	342	seconds, and then every C<$repeat> seconds. The timer does his best not
239	callback processing is not taken into account, so the timer will slowly	343	to drift, but it will not invoke the timer more often then once per event
240	drift. If that isn't acceptable, look at EV::periodic.	344	loop iteration, and might drift in other cases. If that isn't acceptable,
		345	look at EV::periodic, which can provide long-term stable timers.
241		346
242	The timer is based on a monotonic clock, that is if somebody is sitting	347	The timer is based on a monotonic clock, that is, if somebody is sitting
243	in front of the machine while the timer is running and changes the system	348	in front of the machine while the timer is running and changes the system
244	clock, the timer will nevertheless run (roughly) the same time.	349	clock, the timer will nevertheless run (roughly) the same time.
245		350
246	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	351	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
247		352
248	=item $w->set ($after, $repeat)	353	=item $w->set ($after, $repeat)
249		354
250	Reconfigures the watcher, see the constructor above for details. Can be at	355	Reconfigures the watcher, see the constructor above for details. Can be called at
251	any time.	356	any time.
252		357
253	=item $w->again	358	=item $w->again
254		359
255	Similar to the C<start> method, but has special semantics for repeating timers:	360	Similar to the C<start> method, but has special semantics for repeating timers:
		361
		362	If the timer is active and non-repeating, it will be stopped.
256		363
257	If the timer is active and repeating, reset the timeout to occur	364	If the timer is active and repeating, reset the timeout to occur
258	C<$repeat> seconds after now.	365	C<$repeat> seconds after now.
259		366
260	If the timer is active and non-repeating, it will be stopped.
261
262	If the timer is in active and repeating, start it.	367	If the timer is inactive and repeating, start it using the repeat value.
263		368
264	Otherwise do nothing.	369	Otherwise do nothing.
265		370
266	This behaviour is useful when you have a timeout for some IO	371	This behaviour is useful when you have a timeout for some IO
267	operation. You create a timer object with the same value for C<$after> and	372	operation. You create a timer object with the same value for C<$after> and
268	C<$repeat>, and then, in the read/write watcher, run the C<again> method	373	C<$repeat>, and then, in the read/write watcher, run the C<again> method
269	on the timeout.	374	on the timeout.
270		375
		376	=back
271		377
		378
		379	=head3 PERIODIC WATCHERS - to cron or not to cron?
		380
		381	=over 4
		382
272	=item $w = EV::periodic $at, $interval, $callback	383	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
273		384
274	=item $w = EV::periodic_ns $at, $interval, $callback	385	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
275		386
276	Similar to EV::timer, but the time is given as an absolute point in time	387	Similar to EV::timer, but is not based on relative timeouts but on
277	(C<$at>), plus an optional C<$interval>.	388	absolute times. Apart from creating "simple" timers that trigger "at" the
		389	specified time, it can also be used for non-drifting absolute timers and
		390	more complex, cron-like, setups that are not adversely affected by time
		391	jumps (i.e. when the system clock is changed by explicit date -s or other
		392	means such as ntpd). It is also the most complex watcher type in EV.
278		393
279	If the C<$interval> is zero, then the callback will be called at the time	394	It has three distinct "modes":
280	C<$at> if that is in the future, or as soon as possible if it is in the
281	past. It will not automatically repeat.
282		395
283	If the C<$interval> is nonzero, then the watcher will always be scheduled	396	=over 4
284	to time out at the next C<$at + N * $interval> time.
285		397
286	This can be used to schedule a callback to run at very regular intervals,	398	=item * absolute timer ($interval = $reschedule_cb = 0)
287	as long as the processing time is less then the interval (otherwise	399
288	obviously events will be skipped).	400	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		401	will not adjust when a time jump occurs, that is, if it is to be run
		402	at January 1st 2011 then it will run when the system time reaches or
		403	surpasses this time.
		404
		405	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		406
		407	In this mode the watcher will always be scheduled to time out at the
		408	next C<$at + N * $interval> time (for some integer N) and then repeat,
		409	regardless of any time jumps.
		410
		411	This can be used to create timers that do not drift with respect to system
		412	time:
		413
		414	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		415
		416	That doesn't mean there will always be 3600 seconds in between triggers,
		417	but only that the the clalback will be called when the system time shows a
		418	full hour (UTC).
289		419
290	Another way to think about it (for the mathematically inclined) is that	420	Another way to think about it (for the mathematically inclined) is that
291	EV::periodic will try to run the callback at the next possible time where	421	EV::periodic will try to run the callback in this mode at the next
292	C<$time = $at (mod $interval)>, regardless of any time jumps.	422	possible time where C<$time = $at (mod $interval)>, regardless of any time
		423	jumps.
293		424
294	This periodic timer is based on "wallclock time", that is, if the clock	425	=item * manual reschedule mode ($reschedule_cb = coderef)
295	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	426
296	the specified time. This means it will never drift (it might jitter, but	427	In this mode $interval and $at are both being ignored. Instead, each
297	it will not drift).	428	time the periodic watcher gets scheduled, the reschedule callback
		429	($reschedule_cb) will be called with the watcher as first, and the current
		430	time as second argument.
		431
		432	I<This callback MUST NOT stop or destroy this or any other periodic
		433	watcher, ever>. If you need to stop it, return 1e30 and stop it
		434	afterwards.
		435
		436	It must return the next time to trigger, based on the passed time value
		437	(that is, the lowest time value larger than to the second argument). It
		438	will usually be called just before the callback will be triggered, but
		439	might be called at other times, too.
		440
		441	This can be used to create very complex timers, such as a timer that
		442	triggers on each midnight, local time (actually 24 hours after the last
		443	midnight, to keep the example simple. If you know a way to do it correctly
		444	in about the same space (without requiring elaborate modules), drop me a
		445	note :):
		446
		447	my $daily = EV::periodic 0, 0, sub {
		448	my ($w, $now) = @_;
		449
		450	use Time::Local ();
		451	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		452	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		453	}, sub {
		454	print "it's midnight or likely shortly after, now\n";
		455	};
		456
		457	=back
298		458
299	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	459	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
300		460
301	=item $w->set ($at, $interval)	461	=item $w->set ($at, $interval, $reschedule_cb)
302		462
303	Reconfigures the watcher, see the constructor above for details. Can be at	463	Reconfigures the watcher, see the constructor above for details. Can be called at
304	any time.	464	any time.
305		465
		466	=item $w->again
		467
		468	Simply stops and starts the watcher again.
		469
		470	=back
		471
		472
		473	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		474
		475	=over 4
306		476
307	=item $w = EV::signal $signal, $callback	477	=item $w = EV::signal $signal, $callback
308		478
309	=item $w = EV::signal_ns $signal, $callback	479	=item $w = EV::signal_ns $signal, $callback
310		480
311	Call the callback when $signal is received (the signal can be specified	481	Call the callback when $signal is received (the signal can be specified by
312	by number or by name, just as with kill or %SIG).	482	number or by name, just as with C<kill> or C<%SIG>).
313		483
314	EV will grab the signal for the process (the kernel only allows one	484	EV will grab the signal for the process (the kernel only allows one
315	component to receive a signal at a time) when you start a signal watcher,	485	component to receive a signal at a time) when you start a signal watcher,
316	and removes it again when you stop it. Perl does the same when you	486	and removes it again when you stop it. Perl does the same when you
317	add/remove callbacks to %SIG, so watch out.	487	add/remove callbacks to C<%SIG>, so watch out.
318		488
319	You can have as many signal watchers per signal as you want.	489	You can have as many signal watchers per signal as you want.
320		490
321	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	491	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
322		492
323	=item $w->set ($signal)	493	=item $w->set ($signal)
324		494
325	Reconfigures the watcher, see the constructor above for details. Can be at	495	Reconfigures the watcher, see the constructor above for details. Can be
326	any time.	496	called at any time.
327		497
328	=item $current_signum = $w->signal	498	=item $current_signum = $w->signal
329		499
330	=item $old_signum = $w->signal ($new_signal)	500	=item $old_signum = $w->signal ($new_signal)
331		501
332	Returns the previously set signal (always as a number not name) and	502	Returns the previously set signal (always as a number not name) and
333	optionally set a new one.	503	optionally set a new one.
334		504
		505	=back
		506
		507
		508	=head3 CHILD WATCHERS - watch out for process status changes
		509
		510	=over 4
335		511
336	=item $w = EV::child $pid, $callback	512	=item $w = EV::child $pid, $callback
337		513
338	=item $w = EV::child_ns $pid, $callback	514	=item $w = EV::child_ns $pid, $callback
339		515
340	Call the callback when a status change for pid C<$pid> (or any pid	516	Call the callback when a status change for pid C<$pid> (or any pid if
341	if C<$pid> is 0) has been received. More precisely: when the process	517	C<$pid> is 0) has been received. More precisely: when the process receives
342	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	518	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
343	changed/zombie children and call the callback.	519	changed/zombie children and call the callback.
344		520
345	Unlike all other callbacks, this callback will be called with an	521	It is valid (and fully supported) to install a child watcher after a child
346	additional third argument which is the exit status. See the C<waitpid>	522	has exited but before the event loop has started its next iteration (for
347	function for details.	523	example, first you C<fork>, then the new child process might exit, and
		524	only then do you install a child watcher in the parent for the new pid).
348		525
		526	You can access both exit (or tracing) status and pid by using the
		527	C<rstatus> and C<rpid> methods on the watcher object.
		528
349	You can have as many pid watchers per pid as you want.	529	You can have as many pid watchers per pid as you want, they will all be
		530	called.
350		531
351	The C<child_ns> variant doesn't start (activate) the newly created watcher.	532	The C<child_ns> variant doesn't start (activate) the newly created watcher.
352		533
353	=item $w->set ($pid)	534	=item $w->set ($pid)
354		535
355	Reconfigures the watcher, see the constructor above for details. Can be at	536	Reconfigures the watcher, see the constructor above for details. Can be called at
356	any time.	537	any time.
357		538
358	=item $current_pid = $w->pid	539	=item $current_pid = $w->pid
359		540
360	=item $old_pid = $w->pid ($new_pid)	541	=item $old_pid = $w->pid ($new_pid)
361		542
362	Returns the previously set process id and optionally set a new one.	543	Returns the previously set process id and optionally set a new one.
363		544
		545	=item $exit_status = $w->rstatus
		546
		547	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		548	in perlfunc).
		549
		550	=item $pid = $w->rpid
		551
		552	Return the pid of the awaited child (useful when you have installed a
		553	watcher for all pids).
		554
		555	=back
		556
		557
		558	=head3 STAT WATCHERS - did the file attributes just change?
		559
		560	=over 4
		561
		562	=item $w = EV::stat $path, $interval, $callback
		563
		564	=item $w = EV::stat_ns $path, $interval, $callback
		565
		566	Call the callback when a file status change has been detected on
		567	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		568	to "path does not exist" is a status change like any other.
		569
		570	The C<$interval> is a recommended polling interval for systems where
		571	OS-supported change notifications don't exist or are not supported. If
		572	you use C<0> then an unspecified default is used (which is highly
		573	recommended!), which is to be expected to be around five seconds usually.
		574
		575	This watcher type is not meant for massive numbers of stat watchers,
		576	as even with OS-supported change notifications, this can be
		577	resource-intensive.
		578
		579	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		580
		581	=item ... = $w->stat
		582
		583	This call is very similar to the perl C<stat> built-in: It stats (using
		584	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		585	well as EV's idea of the current stat values) to the values found.
		586
		587	In scalar context, a boolean is return indicating success or failure of
		588	the stat. In list context, the same 13-value list as with stat is returned
		589	(except that the blksize and blocks fields are not reliable).
		590
		591	In the case of an error, errno is set to C<ENOENT> (regardless of the
		592	actual error value) and the C<nlink> value is forced to zero (if the stat
		593	was successful then nlink is guaranteed to be non-zero).
		594
		595	See also the next two entries for more info.
		596
		597	=item ... = $w->attr
		598
		599	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		600	the values most recently detected by EV. See the next entry for more info.
		601
		602	=item ... = $w->prev
		603
		604	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		605	the previous set of values, before the change.
		606
		607	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		608	to the values found I<before> a change was detected, while C<< $w->attr >>
		609	returns the values found leading to the change detection. The difference (if any)
		610	between C<prev> and C<attr> is what triggered the callback.
		611
		612	If you did something to the filesystem object and do not want to trigger
		613	yet another change, you can call C<stat> to update EV's idea of what the
		614	current attributes are.
		615
		616	=item $w->set ($path, $interval)
		617
		618	Reconfigures the watcher, see the constructor above for details. Can be
		619	called at any time.
		620
		621	=item $current_path = $w->path
		622
		623	=item $old_path = $w->path ($new_path)
		624
		625	Returns the previously set path and optionally set a new one.
		626
		627	=item $current_interval = $w->interval
		628
		629	=item $old_interval = $w->interval ($new_interval)
		630
		631	Returns the previously set interval and optionally set a new one. Can be
		632	used to query the actual interval used.
		633
		634	=back
		635
		636
		637	=head3 IDLE WATCHERS - when you've got nothing better to do...
		638
		639	=over 4
364		640
365	=item $w = EV::idle $callback	641	=item $w = EV::idle $callback
366		642
367	=item $w = EV::idle_ns $callback	643	=item $w = EV::idle_ns $callback
368		644
…		…
372	The process will not block as long as any idle watchers are active, and	648	The process will not block as long as any idle watchers are active, and
373	they will be called repeatedly until stopped.	649	they will be called repeatedly until stopped.
374		650
375	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	651	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
376		652
		653	=back
		654
		655
		656	=head3 PREPARE WATCHERS - customise your event loop!
		657
		658	=over 4
377		659
378	=item $w = EV::prepare $callback	660	=item $w = EV::prepare $callback
379		661
380	=item $w = EV::prepare_ns $callback	662	=item $w = EV::prepare_ns $callback
381		663
…		…
384		666
385	See the EV::check watcher, below, for explanations and an example.	667	See the EV::check watcher, below, for explanations and an example.
386		668
387	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	669	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
388		670
		671	=back
		672
		673
		674	=head3 CHECK WATCHERS - customise your event loop even more!
		675
		676	=over 4
389		677
390	=item $w = EV::check $callback	678	=item $w = EV::check $callback
391		679
392	=item $w = EV::check_ns $callback	680	=item $w = EV::check_ns $callback
393		681
…		…
405	# do nothing unless active	693	# do nothing unless active
406	$dispatcher->{_event_queue_h}	694	$dispatcher->{_event_queue_h}
407	or return;	695	or return;
408		696
409	# make the dispatcher handle any outstanding stuff	697	# make the dispatcher handle any outstanding stuff
		698	... not shown
410		699
411	# create an IO watcher for each and every socket	700	# create an IO watcher for each and every socket
412	@snmp_watcher = (	701	@snmp_watcher = (
413	(map { EV::io $_, EV::READ, sub { } }	702	(map { EV::io $_, EV::READ, sub { } }
414	keys %{ $dispatcher->{_descriptors} }),	703	keys %{ $dispatcher->{_descriptors} }),
		704
		705	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		706	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		707	0, sub { },
415	);	708	);
416
417	# if there are any timeouts, also create a timer
418	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
419	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
420	};	709	};
421		710
422	The callbacks are irrelevant, the only purpose of those watchers is	711	The callbacks are irrelevant (and are not even being called), the
423	to wake up the process as soon as one of those events occurs (socket	712	only purpose of those watchers is to wake up the process as soon as
424	readable, or timer timed out). The corresponding EV::check watcher will then	713	one of those events occurs (socket readable, or timer timed out). The
425	clean up:	714	corresponding EV::check watcher will then clean up:
426		715
427	our $snmp_check = EV::check sub {	716	our $snmp_check = EV::check sub {
428	# destroy all watchers	717	# destroy all watchers
429	@snmp_watcher = ();	718	@snmp_watcher = ();
430		719
431	# make the dispatcher handle any new stuff	720	# make the dispatcher handle any new stuff
		721	... not shown
432	};	722	};
433		723
434	The callbacks of the created watchers will not be called as the watchers	724	The callbacks of the created watchers will not be called as the watchers
435	are destroyed before this cna happen (remember EV::check gets called	725	are destroyed before this cna happen (remember EV::check gets called
436	first).	726	first).
437		727
438	The C<check_ns> variant doesn't start (activate) the newly created watcher.	728	The C<check_ns> variant doesn't start (activate) the newly created watcher.
439		729
440	=back	730	=back
441		731
		732
		733	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		734
		735	Fork watchers are called when a C<fork ()> was detected. The invocation
		736	is done before the event loop blocks next and before C<check> watchers
		737	are being called, and only in the child after the fork.
		738
		739	=over 4
		740
		741	=item $w = EV::fork $callback
		742
		743	=item $w = EV::fork_ns $callback
		744
		745	Call the callback before the event loop is resumed in the child process
		746	after a fork.
		747
		748	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		749
		750	=back
		751
		752
442	=head1 THREADS	753	=head1 THREADS
443		754
444	Threads are not supported by this in any way. Perl pseudo-threads is evil	755	Threads are not supported by this module in any way. Perl pseudo-threads
445	stuff and must die.	756	is evil stuff and must die. As soon as Perl gains real threads I will work
		757	on thread support for it.
		758
		759	=head1 FORK
		760
		761	Most of the "improved" event delivering mechanisms of modern operating
		762	systems have quite a few problems with fork(2) (to put it bluntly: it is
		763	not supported and usually destructive). Libev makes it possible to work
		764	around this by having a function that recreates the kernel state after
		765	fork in the child.
		766
		767	On non-win32 platforms, this module requires the pthread_atfork
		768	functionality to do this automatically for you. This function is quite
		769	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		770	negligible, because everything the function currently does is set a flag
		771	that is checked only when the event loop gets used the next time, so when
		772	you do fork but not use EV, the overhead is minimal.
		773
		774	On win32, there is no notion of fork so all this doesn't apply, of course.
446		775
447	=cut	776	=cut
448		777
449	our $DIED = sub {	778	our $DIED = sub {
450	warn "EV: error in callback (ignoring): $@";	779	warn "EV: error in callback (ignoring): $@";
451	};	780	};
452		781
453	init;	782	default_loop
454		783	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
455	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
456		784
457	1;	785	1;
458		786
459	=head1 SEE ALSO	787	=head1 SEE ALSO
460		788
461	L<EV::DNS>, L<EV::AnyEvent>.	789	L<EV::DNS>.
462		790
463	=head1 AUTHOR	791	=head1 AUTHOR
464		792
465	Marc Lehmann <schmorp@schmorp.de>	793	Marc Lehmann <schmorp@schmorp.de>
466	http://home.schmorp.de/	794	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.22 by root, Fri Nov 2 11:02:22 2007 UTC vs. Revision 1.57 by root, Wed Nov 28 17:32:24 2007 UTC

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Revision 1.22 by root, Fri Nov 2 11:02:22 2007 UTC vs.
Revision 1.57 by root, Wed Nov 28 17:32:24 2007 UTC