[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 1.61 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	# 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 = '1.6';
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 $count = EV::loop_count
126		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
127	=head2 WATCHER	166	=head2 WATCHER OBJECTS
128		167
129	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
130	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
131	would create an EV::io watcher for that:	170	would create an EV::io watcher for that:
132		171
…		…
150	In the rare case where one wants to create a watcher but not start it at	189	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	190	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.	191	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
153		192
154	Please note that a watcher will automatically be stopped when the watcher	193	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	194	object is destroyed, so you I<need> to keep the watcher objects returned by
156	the constructors.	195	the constructors.
157		196
158	=head2 WATCHER TYPES	197	Also, all methods changing some aspect of a watcher (->set, ->priority,
		198	->fh and so on) automatically stop and start it again if it is active,
		199	which means pending events get lost.
159		200
160	Now lets move to the existing watcher types and asociated methods.	201	=head2 COMMON WATCHER METHODS
161		202
162	The following methods are available for all watchers. Then followes a	203	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		204
167	=over 4	205	=over 4
168		206
169	=item $w->start	207	=item $w->start
170		208
…		…
180		218
181	=item $bool = $w->is_active	219	=item $bool = $w->is_active
182		220
183	Returns true if the watcher is active, false otherwise.	221	Returns true if the watcher is active, false otherwise.
184		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!");
		234
185	=item $current_cb = $w->cb	235	=item $current_cb = $w->cb
186		236
187	=item $old_cb = $w->cb ($new_cb)	237	=item $old_cb = $w->cb ($new_cb)
188		238
189	Queries the callback on the watcher and optionally changes it. You cna do	239	Queries the callback on the watcher and optionally changes it. You can do
190	this at any time.	240	this at any time without the watcher restarting.
		241
		242	=item $current_priority = $w->priority
		243
		244	=item $old_priority = $w->priority ($new_priority)
		245
		246	Queries the priority on the watcher and optionally changes it. Pending
		247	watchers with higher priority will be invoked first. The valid range of
		248	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		249	-2). If the priority is outside this range it will automatically be
		250	normalised to the nearest valid priority.
		251
		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.
191		256
192	=item $w->trigger ($revents)	257	=item $w->trigger ($revents)
193		258
194	Call the callback now with the given event mask.	259	Call the callback now with the given event mask.
195		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
196		299
197	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	300	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
198		301
199	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	302	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
200		303
201	As long as the returned watcher object is alive, call the C<$callback>	304	As long as the returned watcher object is alive, call the C<$callback>
202	when the events specified in C<$eventmask>.	305	when at least one of events specified in C<$eventmask> occurs.
203		306
204	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:
205		308
206	EV::READ wait until read() wouldn't block anymore	309	EV::READ wait until read() wouldn't block anymore
207	EV::WRITE wait until write() wouldn't block anymore	310	EV::WRITE wait until write() wouldn't block anymore
…		…
223		326
224	=item $old_eventmask = $w->events ($new_eventmask)	327	=item $old_eventmask = $w->events ($new_eventmask)
225		328
226	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.
227		330
		331	=back
		332
		333
		334	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		335
		336	=over 4
228		337
229	=item $w = EV::timer $after, $repeat, $callback	338	=item $w = EV::timer $after, $repeat, $callback
230		339
231	=item $w = EV::timer_ns $after, $repeat, $callback	340	=item $w = EV::timer_ns $after, $repeat, $callback
232		341
233	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	342	Calls the callback after C<$after> seconds (which may be fractional). If
234	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
235	callback returns.	344	value as $after) after the callback returns.
236		345
237	This means that the callback would be called roughly after C<$after>	346	This means that the callback would be called roughly after C<$after>
238	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	347	seconds, and then every C<$repeat> seconds. The timer does his best not
239	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
240	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.
241		351
242	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
243	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
244	clock, the timer will nevertheless run (roughly) the same time.	354	clock, the timer will nevertheless run (roughly) the same time.
245		355
246	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.
247		357
248	=item $w->set ($after, $repeat)	358	=item $w->set ($after, $repeat)
249		359
250	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
251	any time.	361	any time.
252		362
253	=item $w->again	363	=item $w->again
254		364
255	Similar to the C<start> method, but has special semantics for repeating timers:	365	Similar to the C<start> method, but has special semantics for repeating timers:
		366
		367	If the timer is active and non-repeating, it will be stopped.
256		368
257	If the timer is active and repeating, reset the timeout to occur	369	If the timer is active and repeating, reset the timeout to occur
258	C<$repeat> seconds after now.	370	C<$repeat> seconds after now.
259		371
260	If the timer is active and non-repeating, it will be stopped.
261
262	If the timer is in active and repeating, start it.	372	If the timer is inactive and repeating, start it using the repeat value.
263		373
264	Otherwise do nothing.	374	Otherwise do nothing.
265		375
266	This behaviour is useful when you have a timeout for some IO	376	This behaviour is useful when you have a timeout for some IO
267	operation. You create a timer object with the same value for C<$after> and	377	operation. You create a timer object with the same value for C<$after> and
268	C<$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
269	on the timeout.	379	on the timeout.
270		380
		381	=back
271		382
		383
		384	=head3 PERIODIC WATCHERS - to cron or not to cron?
		385
		386	=over 4
		387
272	=item $w = EV::periodic $at, $interval, $callback	388	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
273		389
274	=item $w = EV::periodic_ns $at, $interval, $callback	390	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
275		391
276	Similar to EV::timer, but the time is given as an absolute point in time	392	Similar to EV::timer, but is not based on relative timeouts but on
277	(C<$at>), plus an optional C<$interval>.	393	absolute times. Apart from creating "simple" timers that trigger "at" the
		394	specified time, it can also be used for non-drifting absolute timers and
		395	more complex, cron-like, setups that are not adversely affected by time
		396	jumps (i.e. when the system clock is changed by explicit date -s or other
		397	means such as ntpd). It is also the most complex watcher type in EV.
278		398
279	If the C<$interval> is zero, then the callback will be called at the time	399	It has three distinct "modes":
280	C<$at> if that is in the future, or as soon as possible if it is in the
281	past. It will not automatically repeat.
282		400
283	If the C<$interval> is nonzero, then the watcher will always be scheduled	401	=over 4
284	to time out at the next C<$at + N * $interval> time.
285		402
286	This can be used to schedule a callback to run at very regular intervals,	403	=item * absolute timer ($interval = $reschedule_cb = 0)
287	as long as the processing time is less then the interval (otherwise	404
288	obviously events will be skipped).	405	This time simply fires at the wallclock time C<$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 $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		420
		421	That doesn't mean there will always be 3600 seconds in between triggers,
		422	but only that the the clalback will be called when the system time shows a
		423	full hour (UTC).
289		424
290	Another way to think about it (for the mathematically inclined) is that	425	Another way to think about it (for the mathematically inclined) is that
291	EV::periodic will try to run the callback at the next possible time where	426	EV::periodic will try to run the callback in this mode at the next
292	C<$time = $at (mod $interval)>, regardless of any time jumps.	427	possible time where C<$time = $at (mod $interval)>, regardless of any time
		428	jumps.
293		429
294	This periodic timer is based on "wallclock time", that is, if the clock	430	=item * manual reschedule mode ($reschedule_cb = coderef)
295	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	431
296	the specified time. This means it will never drift (it might jitter, but	432	In this mode $interval and $at are both being ignored. Instead, each
297	it will not drift).	433	time the periodic watcher gets scheduled, the reschedule callback
		434	($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
298		463
299	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.
300		465
301	=item $w->set ($at, $interval)	466	=item $w->set ($at, $interval, $reschedule_cb)
302		467
303	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
304	any time.	469	any time.
305		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
306		481
307	=item $w = EV::signal $signal, $callback	482	=item $w = EV::signal $signal, $callback
308		483
309	=item $w = EV::signal_ns $signal, $callback	484	=item $w = EV::signal_ns $signal, $callback
310		485
311	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
312	by number or by name, just as with kill or %SIG).	487	number or by name, just as with C<kill> or C<%SIG>).
313		488
314	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
315	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,
316	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
317	add/remove callbacks to %SIG, so watch out.	492	add/remove callbacks to C<%SIG>, so watch out.
318		493
319	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.
320		495
321	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.
322		497
323	=item $w->set ($signal)	498	=item $w->set ($signal)
324		499
325	Reconfigures the watcher, see the constructor above for details. Can be at	500	Reconfigures the watcher, see the constructor above for details. Can be
326	any time.	501	called at any time.
327		502
328	=item $current_signum = $w->signal	503	=item $current_signum = $w->signal
329		504
330	=item $old_signum = $w->signal ($new_signal)	505	=item $old_signum = $w->signal ($new_signal)
331		506
332	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
333	optionally set a new one.	508	optionally set a new one.
334		509
		510	=back
		511
		512
		513	=head3 CHILD WATCHERS - watch out for process status changes
		514
		515	=over 4
335		516
336	=item $w = EV::child $pid, $callback	517	=item $w = EV::child $pid, $callback
337		518
338	=item $w = EV::child_ns $pid, $callback	519	=item $w = EV::child_ns $pid, $callback
339		520
340	Call the callback when a status change for pid C<$pid> (or any pid	521	Call the callback when a status change for pid C<$pid> (or any pid if
341	if C<$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
342	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
343	changed/zombie children and call the callback.	524	changed/zombie children and call the callback.
344		525
345	Unlike all other callbacks, this callback will be called with an	526	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>	527	has exited but before the event loop has started its next iteration (for
347	function for details.	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).
348		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
349	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.
350		536
351	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.
352		538
353	=item $w->set ($pid)	539	=item $w->set ($pid)
354		540
355	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
356	any time.	542	any time.
357		543
358	=item $current_pid = $w->pid	544	=item $current_pid = $w->pid
359		545
360	=item $old_pid = $w->pid ($new_pid)	546	=item $old_pid = $w->pid ($new_pid)
361		547
362	Returns the previously set process id and optionally set a new one.	548	Returns the previously set process id and optionally set a new one.
363		549
		550	=item $exit_status = $w->rstatus
		551
		552	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		553	in perlfunc).
		554
		555	=item $pid = $w->rpid
		556
		557	Return the pid of the awaited child (useful when you have installed a
		558	watcher for all pids).
		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
364		645
365	=item $w = EV::idle $callback	646	=item $w = EV::idle $callback
366		647
367	=item $w = EV::idle_ns $callback	648	=item $w = EV::idle_ns $callback
368		649
…		…
372	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
373	they will be called repeatedly until stopped.	654	they will be called repeatedly until stopped.
374		655
375	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.
376		657
		658	=back
		659
		660
		661	=head3 PREPARE WATCHERS - customise your event loop!
		662
		663	=over 4
377		664
378	=item $w = EV::prepare $callback	665	=item $w = EV::prepare $callback
379		666
380	=item $w = EV::prepare_ns $callback	667	=item $w = EV::prepare_ns $callback
381		668
…		…
384		671
385	See the EV::check watcher, below, for explanations and an example.	672	See the EV::check watcher, below, for explanations and an example.
386		673
387	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.
388		675
		676	=back
		677
		678
		679	=head3 CHECK WATCHERS - customise your event loop even more!
		680
		681	=over 4
389		682
390	=item $w = EV::check $callback	683	=item $w = EV::check $callback
391		684
392	=item $w = EV::check_ns $callback	685	=item $w = EV::check_ns $callback
393		686
…		…
405	# do nothing unless active	698	# do nothing unless active
406	$dispatcher->{_event_queue_h}	699	$dispatcher->{_event_queue_h}
407	or return;	700	or return;
408		701
409	# make the dispatcher handle any outstanding stuff	702	# make the dispatcher handle any outstanding stuff
		703	... not shown
410		704
411	# create an IO watcher for each and every socket	705	# create an IO watcher for each and every socket
412	@snmp_watcher = (	706	@snmp_watcher = (
413	(map { EV::io $_, EV::READ, sub { } }	707	(map { EV::io $_, EV::READ, sub { } }
414	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 { },
415	);	713	);
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	};	714	};
421		715
422	The callbacks are irrelevant, the only purpose of those watchers is	716	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	717	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	718	one of those events occurs (socket readable, or timer timed out). The
425	clean up:	719	corresponding EV::check watcher will then clean up:
426		720
427	our $snmp_check = EV::check sub {	721	our $snmp_check = EV::check sub {
428	# destroy all watchers	722	# destroy all watchers
429	@snmp_watcher = ();	723	@snmp_watcher = ();
430		724
431	# make the dispatcher handle any new stuff	725	# make the dispatcher handle any new stuff
		726	... not shown
432	};	727	};
433		728
434	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
435	are destroyed before this cna happen (remember EV::check gets called	730	are destroyed before this cna happen (remember EV::check gets called
436	first).	731	first).
437		732
438	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.
439		734
440	=back	735	=back
441		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
442	=head1 THREADS	777	=head1 THREADS
443		778
444	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
445	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.
446		799
447	=cut	800	=cut
448		801
449	our $DIED = sub {	802	our $DIED = sub {
450	warn "EV: error in callback (ignoring): $@";	803	warn "EV: error in callback (ignoring): $@";
451	};	804	};
452		805
453	init;	806	default_loop
454		807	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
455	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
456		808
457	1;	809	1;
458		810
459	=head1 SEE ALSO	811	=head1 SEE ALSO
460		812
461	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).
462		815
463	=head1 AUTHOR	816	=head1 AUTHOR
464		817
465	Marc Lehmann <schmorp@schmorp.de>	818	Marc Lehmann <schmorp@schmorp.de>
466	http://home.schmorp.de/	819	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 1.61 by root, Thu Dec 6 03:13:07 2007 UTC

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Revision 1.61 by root, Thu Dec 6 03:13:07 2007 UTC