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

Comparing EV/EV.pm (file contents):
Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs.
Revision 1.63 by root, Fri Dec 7 18:11:21 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>, or just about in any case
		64	because it has much more detailed information.
57		65
58	=cut	66	=cut
59		67
60	package EV;	68	package EV;
61		69
62	use strict;	70	use strict;
63		71
64	BEGIN {	72	BEGIN {
65	our $VERSION = '0.1';	73	our $VERSION = '1.71';
66	use XSLoader;	74	use XSLoader;
67	XSLoader::load "EV", $VERSION;	75	XSLoader::load "EV", $VERSION;
68	}	76	}
69		77
70	@EV::Io::ISA =	78	@EV::IO::ISA =
71	@EV::Timer::ISA =	79	@EV::Timer::ISA =
72	@EV::Periodic::ISA =	80	@EV::Periodic::ISA =
73	@EV::Signal::ISA =	81	@EV::Signal::ISA =
		82	@EV::Child::ISA =
		83	@EV::Stat::ISA =
74	@EV::Idle::ISA =	84	@EV::Idle::ISA =
75	@EV::Prepare::ISA =	85	@EV::Prepare::ISA =
76	@EV::Check::ISA =	86	@EV::Check::ISA =
77	@EV::Child::ISA = "EV::Watcher";	87	@EV::Embed::ISA =
		88	@EV::Fork::ISA =
		89	"EV::Watcher";
78		90
79	=head1 BASIC INTERFACE	91	=head1 BASIC INTERFACE
80		92
81	=over 4	93	=over 4
82		94
…		…
96		108
97	Returns the time the last event loop iteration has been started. This	109	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	110	is the time that (relative) timers are based on, and refering to it is
99	usually faster then calling EV::time.	111	usually faster then calling EV::time.
100		112
101	=item $method = EV::ev_method	113	=item $method = EV::method
102		114
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	115	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
104	or EV::METHOD_EPOLL).	116	or EV::METHOD_EPOLL).
105		117
106	=item EV::loop [$flags]	118	=item EV::loop [$flags]
107		119
108	Begin checking for events and calling callbacks. It returns when a	120	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	121	callback calls EV::unloop.
110		122
111	The $flags argument can be one of the following:	123	The $flags argument can be one of the following:
112		124
113	0 as above	125	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	126	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	127	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		128
117	=item EV::loop_done [$how]	129	=item EV::unloop [$how]
118		130
119	When called with no arguments or an argument of 1, makes the innermost	131	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	132	innermost call to EV::loop return.
121		133
122	When called with an agrument of 2, all calls to EV::loop will return as	134	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	135	fast as possible.
124		136
125	=back	137	=item $count = EV::loop_count
126		138
		139	Return the number of times the event loop has polled for new
		140	events. Sometiems useful as a generation counter.
		141
		142	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		143
		144	This function rolls together an I/O and a timer watcher for a single
		145	one-shot event without the need for managing a watcher object.
		146
		147	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		148	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		149	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		150	you do not want to wait for some I/O event, specify C<undef> for
		151	C<$fh_or_undef> and C<0> for C<$events>).
		152
		153	If timeout is C<undef> or negative, then there will be no
		154	timeout. Otherwise a EV::timer with this value will be started.
		155
		156	When an error occurs or either the timeout or I/O watcher triggers, then
		157	the callback will be called with the received event set (in general
		158	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		159	C<EV::WRITE> and C<EV::TIMEOUT>).
		160
		161	EV::once doesn't return anything: the watchers stay active till either
		162	of them triggers, then they will be stopped and freed, and the callback
		163	invoked.
		164
		165	=back
		166
127	=head2 WATCHER	167	=head2 WATCHER OBJECTS
128		168
129	A watcher is an object that gets created to record your interest in some	169	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	170	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	171	would create an EV::io watcher for that:
132		172
…		…
141	events.	181	events.
142		182
143	Each watcher type has its associated bit in revents, so you can use the	183	Each watcher type has its associated bit in revents, so you can use the
144	same callback for multiple watchers. The event mask is named after the	184	same callback for multiple watchers. The event mask is named after the
145	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	185	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
146	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	186	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
147	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	187	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	188	uses EV::TIMEOUT).
149		189
150	In the rare case where one wants to create a watcher but not start it at	190	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	191	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.	192	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
153		193
154	Please note that a watcher will automatically be stopped when the watcher	194	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	195	object is destroyed, so you I<need> to keep the watcher objects returned by
156	the constructors.	196	the constructors.
157		197
158	=head2 WATCHER TYPES	198	Also, all methods changing some aspect of a watcher (->set, ->priority,
		199	->fh and so on) automatically stop and start it again if it is active,
		200	which means pending events get lost.
159		201
160	Now lets move to the existing watcher types and asociated methods.	202	=head2 COMMON WATCHER METHODS
161		203
162	The following methods are available for all watchers. Then followes a	204	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		205
167	=over 4	206	=over 4
168		207
169	=item $w->start	208	=item $w->start
170		209
…		…
174		213
175	=item $w->stop	214	=item $w->stop
176		215
177	Stop a watcher if it is active. Also clear any pending events (events that	216	Stop a watcher if it is active. Also clear any pending events (events that
178	have been received but that didn't yet result in a callback invocation),	217	have been received but that didn't yet result in a callback invocation),
179	regardless of wether the watcher was active or not.	218	regardless of whether the watcher was active or not.
180		219
181	=item $bool = $w->is_active	220	=item $bool = $w->is_active
182		221
183	Returns true if the watcher is active, false otherwise.	222	Returns true if the watcher is active, false otherwise.
184		223
		224	=item $current_data = $w->data
		225
		226	=item $old_data = $w->data ($new_data)
		227
		228	Queries a freely usable data scalar on the watcher and optionally changes
		229	it. This is a way to associate custom data with a watcher:
		230
		231	my $w = EV::timer 60, 0, sub {
		232	warn $_[0]->data;
		233	};
		234	$w->data ("print me!");
		235
185	=item $current_cb = $w->cb	236	=item $current_cb = $w->cb
186		237
187	=item $old_cb = $w->cb ($new_cb)	238	=item $old_cb = $w->cb ($new_cb)
188		239
189	Queries the callback on the watcher and optionally changes it. You cna do	240	Queries the callback on the watcher and optionally changes it. You can do
190	this at any time.	241	this at any time without the watcher restarting.
		242
		243	=item $current_priority = $w->priority
		244
		245	=item $old_priority = $w->priority ($new_priority)
		246
		247	Queries the priority on the watcher and optionally changes it. Pending
		248	watchers with higher priority will be invoked first. The valid range of
		249	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		250	-2). If the priority is outside this range it will automatically be
		251	normalised to the nearest valid priority.
		252
		253	The default priority of any newly-created watcher is 0.
		254
		255	Note that the priority semantics have not yet been fleshed out and are
		256	subject to almost certain change.
191		257
192	=item $w->trigger ($revents)	258	=item $w->trigger ($revents)
193		259
194	Call the callback now with the given event mask.	260	Call the callback now with the given event mask.
195		261
		262	=item $previous_state = $w->keepalive ($bool)
		263
		264	Normally, C<EV::loop> will return when there are no active watchers
		265	(which is a "deadlock" because no progress can be made anymore). This is
		266	convinient because it allows you to start your watchers (and your jobs),
		267	call C<EV::loop> once and when it returns you know that all your jobs are
		268	finished (or they forgot to register some watchers for their task :).
		269
		270	Sometimes, however, this gets in your way, for example when you the module
		271	that calls C<EV::loop> (usually the main program) is not the same module
		272	as a long-living watcher (for example a DNS client module written by
		273	somebody else even). Then you might want any outstanding requests to be
		274	handled, but you would not want to keep C<EV::loop> from returning just
		275	because you happen to have this long-running UDP port watcher.
		276
		277	In this case you can clear the keepalive status, which means that even
		278	though your watcher is active, it won't keep C<EV::loop> from returning.
		279
		280	The initial value for keepalive is true (enabled), and you cna change it
		281	any time.
		282
		283	Example: Register an I/O watcher for some UDP socket but do not keep the
		284	event loop from running just because of that watcher.
		285
		286	my $udp_socket = ...
		287	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		288	$udp_watcher->keepalive (0);
		289
		290	=back
		291
		292
		293	=head2 WATCHER TYPES
		294
		295	Each of the following subsections describes a single watcher type.
		296
		297	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		298
		299	=over 4
196		300
197	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	301	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
198		302
199	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	303	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
200		304
201	As long as the returned watcher object is alive, call the C<$callback>	305	As long as the returned watcher object is alive, call the C<$callback>
202	when the events specified in C<$eventmask>.	306	when at least one of events specified in C<$eventmask> occurs.
203		307
204	The $eventmask can be one or more of these constants ORed together:	308	The $eventmask can be one or more of these constants ORed together:
205		309
206	EV::READ wait until read() wouldn't block anymore	310	EV::READ wait until read() wouldn't block anymore
207	EV::WRITE wait until write() wouldn't block anymore	311	EV::WRITE wait until write() wouldn't block anymore
…		…
223		327
224	=item $old_eventmask = $w->events ($new_eventmask)	328	=item $old_eventmask = $w->events ($new_eventmask)
225		329
226	Returns the previously set event mask and optionally set a new one.	330	Returns the previously set event mask and optionally set a new one.
227		331
		332	=back
		333
		334
		335	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		336
		337	=over 4
228		338
229	=item $w = EV::timer $after, $repeat, $callback	339	=item $w = EV::timer $after, $repeat, $callback
230		340
231	=item $w = EV::timer_ns $after, $repeat, $callback	341	=item $w = EV::timer_ns $after, $repeat, $callback
232		342
233	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	343	Calls the callback after C<$after> seconds (which may be fractional). If
234	the timer will be restarted (with the $repeat value as $after) after the	344	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
235	callback returns.	345	value as $after) after the callback returns.
236		346
237	This means that the callback would be called roughly after C<$after>	347	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	348	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	349	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.	350	loop iteration, and might drift in other cases. If that isn't acceptable,
		351	look at EV::periodic, which can provide long-term stable timers.
241		352
242	The timer is based on a monotonic clock, that is if somebody is sitting	353	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	354	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.	355	clock, the timer will nevertheless run (roughly) the same time.
245		356
246	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	357	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
247		358
248	=item $w->set ($after, $repeat)	359	=item $w->set ($after, $repeat)
249		360
250	Reconfigures the watcher, see the constructor above for details. Can be at	361	Reconfigures the watcher, see the constructor above for details. Can be called at
251	any time.	362	any time.
252		363
253	=item $w->again	364	=item $w->again
254		365
255	Similar to the C<start> method, but has special semantics for repeating timers:	366	Similar to the C<start> method, but has special semantics for repeating timers:
		367
		368	If the timer is active and non-repeating, it will be stopped.
256		369
257	If the timer is active and repeating, reset the timeout to occur	370	If the timer is active and repeating, reset the timeout to occur
258	C<$repeat> seconds after now.	371	C<$repeat> seconds after now.
259		372
260	If the timer is active and non-repeating, it will be stopped.
261
262	If the timer is in active and repeating, start it.	373	If the timer is inactive and repeating, start it using the repeat value.
263		374
264	Otherwise do nothing.	375	Otherwise do nothing.
265		376
266	This behaviour is useful when you have a timeout for some IO	377	This behaviour is useful when you have a timeout for some IO
267	operation. You create a timer object with the same value for C<$after> and	378	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	379	C<$repeat>, and then, in the read/write watcher, run the C<again> method
269	on the timeout.	380	on the timeout.
270		381
		382	=back
271		383
		384
		385	=head3 PERIODIC WATCHERS - to cron or not to cron?
		386
		387	=over 4
		388
272	=item $w = EV::periodic $at, $interval, $callback	389	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
273		390
274	=item $w = EV::periodic_ns $at, $interval, $callback	391	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
275		392
276	Similar to EV::timer, but the time is given as an absolute point in time	393	Similar to EV::timer, but is not based on relative timeouts but on
277	(C<$at>), plus an optional C<$interval>.	394	absolute times. Apart from creating "simple" timers that trigger "at" the
		395	specified time, it can also be used for non-drifting absolute timers and
		396	more complex, cron-like, setups that are not adversely affected by time
		397	jumps (i.e. when the system clock is changed by explicit date -s or other
		398	means such as ntpd). It is also the most complex watcher type in EV.
278		399
279	If the C<$interval> is zero, then the callback will be called at the time	400	It has three distinct "modes":
280	C<$at> if that is in the future, or as soon as possible if it is in the
281	past. It will not automatically repeat.
282		401
283	If the C<$interval> is nonzero, then the watcher will always be scheduled	402	=over 4
284	to time out at the next C<$at + N * $interval> time.
285		403
286	This can be used to schedule a callback to run at very regular intervals,	404	=item * absolute timer ($interval = $reschedule_cb = 0)
287	as long as the processing time is less then the interval (otherwise	405
288	obviously events will be skipped).	406	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		407	will not adjust when a time jump occurs, that is, if it is to be run
		408	at January 1st 2011 then it will run when the system time reaches or
		409	surpasses this time.
		410
		411	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		412
		413	In this mode the watcher will always be scheduled to time out at the
		414	next C<$at + N * $interval> time (for some integer N) and then repeat,
		415	regardless of any time jumps.
		416
		417	This can be used to create timers that do not drift with respect to system
		418	time:
		419
		420	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		421
		422	That doesn't mean there will always be 3600 seconds in between triggers,
		423	but only that the the clalback will be called when the system time shows a
		424	full hour (UTC).
289		425
290	Another way to think about it (for the mathematically inclined) is that	426	Another way to think about it (for the mathematically inclined) is that
291	EV::periodic will try to run the callback at the next possible time where	427	EV::periodic will try to run the callback in this mode at the next
292	C<$time = $at (mod $interval)>, regardless of any time jumps.	428	possible time where C<$time = $at (mod $interval)>, regardless of any time
		429	jumps.
293		430
294	This periodic timer is based on "wallclock time", that is, if the clock	431	=item * manual reschedule mode ($reschedule_cb = coderef)
295	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	432
296	the specified time. This means it will never drift (it might jitter, but	433	In this mode $interval and $at are both being ignored. Instead, each
297	it will not drift).	434	time the periodic watcher gets scheduled, the reschedule callback
		435	($reschedule_cb) will be called with the watcher as first, and the current
		436	time as second argument.
		437
		438	I<This callback MUST NOT stop or destroy this or any other periodic
		439	watcher, ever>. If you need to stop it, return 1e30 and stop it
		440	afterwards.
		441
		442	It must return the next time to trigger, based on the passed time value
		443	(that is, the lowest time value larger than to the second argument). It
		444	will usually be called just before the callback will be triggered, but
		445	might be called at other times, too.
		446
		447	This can be used to create very complex timers, such as a timer that
		448	triggers on each midnight, local time (actually 24 hours after the last
		449	midnight, to keep the example simple. If you know a way to do it correctly
		450	in about the same space (without requiring elaborate modules), drop me a
		451	note :):
		452
		453	my $daily = EV::periodic 0, 0, sub {
		454	my ($w, $now) = @_;
		455
		456	use Time::Local ();
		457	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		458	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		459	}, sub {
		460	print "it's midnight or likely shortly after, now\n";
		461	};
		462
		463	=back
298		464
299	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	465	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
300		466
301	=item $w->set ($at, $interval)	467	=item $w->set ($at, $interval, $reschedule_cb)
302		468
303	Reconfigures the watcher, see the constructor above for details. Can be at	469	Reconfigures the watcher, see the constructor above for details. Can be called at
304	any time.	470	any time.
305		471
		472	=item $w->again
		473
		474	Simply stops and starts the watcher again.
		475
		476	=back
		477
		478
		479	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		480
		481	=over 4
306		482
307	=item $w = EV::signal $signal, $callback	483	=item $w = EV::signal $signal, $callback
308		484
309	=item $w = EV::signal_ns $signal, $callback	485	=item $w = EV::signal_ns $signal, $callback
310		486
311	Call the callback when $signal is received (the signal can be specified	487	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).	488	number or by name, just as with C<kill> or C<%SIG>).
313		489
314	EV will grab the signal for the process (the kernel only allows one	490	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,	491	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	492	and removes it again when you stop it. Perl does the same when you
317	add/remove callbacks to %SIG, so watch out.	493	add/remove callbacks to C<%SIG>, so watch out.
318		494
319	You can have as many signal watchers per signal as you want.	495	You can have as many signal watchers per signal as you want.
320		496
321	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	497	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
322		498
323	=item $w->set ($signal)	499	=item $w->set ($signal)
324		500
325	Reconfigures the watcher, see the constructor above for details. Can be at	501	Reconfigures the watcher, see the constructor above for details. Can be
		502	called at any time.
		503
		504	=item $current_signum = $w->signal
		505
		506	=item $old_signum = $w->signal ($new_signal)
		507
		508	Returns the previously set signal (always as a number not name) and
		509	optionally set a new one.
		510
		511	=back
		512
		513
		514	=head3 CHILD WATCHERS - watch out for process status changes
		515
		516	=over 4
		517
		518	=item $w = EV::child $pid, $callback
		519
		520	=item $w = EV::child_ns $pid, $callback
		521
		522	Call the callback when a status change for pid C<$pid> (or any pid if
		523	C<$pid> is 0) has been received. More precisely: when the process receives
		524	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
		525	changed/zombie children and call the callback.
		526
		527	It is valid (and fully supported) to install a child watcher after a child
		528	has exited but before the event loop has started its next iteration (for
		529	example, first you C<fork>, then the new child process might exit, and
		530	only then do you install a child watcher in the parent for the new pid).
		531
		532	You can access both exit (or tracing) status and pid by using the
		533	C<rstatus> and C<rpid> methods on the watcher object.
		534
		535	You can have as many pid watchers per pid as you want, they will all be
		536	called.
		537
		538	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		539
		540	=item $w->set ($pid)
		541
		542	Reconfigures the watcher, see the constructor above for details. Can be called at
326	any time.	543	any time.
327		544
		545	=item $current_pid = $w->pid
328		546
329	=item $w = EV::child $pid, $callback	547	=item $old_pid = $w->pid ($new_pid)
330		548
331	=item $w = EV::child_ns $pid, $callback	549	Returns the previously set process id and optionally set a new one.
332		550
333	Call the callback when a status change for pid C<$pid> (or any pid	551	=item $exit_status = $w->rstatus
334	if C<$pid> is 0) has been received. More precisely: when the process
335	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all
336	changed/zombie children and call the callback.
337		552
338	Unlike all other callbacks, this callback will be called with an	553	Return the exit/wait status (as returned by waitpid, see the waitpid entry
339	additional third argument which is the exit status. See the C<waitpid>	554	in perlfunc).
340	function for details.
341		555
342	You can have as many pid watchers per pid as you want.	556	=item $pid = $w->rpid
343		557
		558	Return the pid of the awaited child (useful when you have installed a
		559	watcher for all pids).
		560
		561	=back
		562
		563
		564	=head3 STAT WATCHERS - did the file attributes just change?
		565
		566	=over 4
		567
		568	=item $w = EV::stat $path, $interval, $callback
		569
		570	=item $w = EV::stat_ns $path, $interval, $callback
		571
		572	Call the callback when a file status change has been detected on
		573	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		574	to "path does not exist" is a status change like any other.
		575
		576	The C<$interval> is a recommended polling interval for systems where
		577	OS-supported change notifications don't exist or are not supported. If
		578	you use C<0> then an unspecified default is used (which is highly
		579	recommended!), which is to be expected to be around five seconds usually.
		580
		581	This watcher type is not meant for massive numbers of stat watchers,
		582	as even with OS-supported change notifications, this can be
		583	resource-intensive.
		584
344	The C<child_ns> variant doesn't start (activate) the newly created watcher.	585	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
345		586
346	=item $w->set ($pid)	587	=item ... = $w->stat
347		588
		589	This call is very similar to the perl C<stat> built-in: It stats (using
		590	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		591	well as EV's idea of the current stat values) to the values found.
		592
		593	In scalar context, a boolean is return indicating success or failure of
		594	the stat. In list context, the same 13-value list as with stat is returned
		595	(except that the blksize and blocks fields are not reliable).
		596
		597	In the case of an error, errno is set to C<ENOENT> (regardless of the
		598	actual error value) and the C<nlink> value is forced to zero (if the stat
		599	was successful then nlink is guaranteed to be non-zero).
		600
		601	See also the next two entries for more info.
		602
		603	=item ... = $w->attr
		604
		605	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		606	the values most recently detected by EV. See the next entry for more info.
		607
		608	=item ... = $w->prev
		609
		610	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		611	the previous set of values, before the change.
		612
		613	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		614	to the values found I<before> a change was detected, while C<< $w->attr >>
		615	returns the values found leading to the change detection. The difference (if any)
		616	between C<prev> and C<attr> is what triggered the callback.
		617
		618	If you did something to the filesystem object and do not want to trigger
		619	yet another change, you can call C<stat> to update EV's idea of what the
		620	current attributes are.
		621
		622	=item $w->set ($path, $interval)
		623
348	Reconfigures the watcher, see the constructor above for details. Can be at	624	Reconfigures the watcher, see the constructor above for details. Can be
349	any time.	625	called at any time.
350		626
		627	=item $current_path = $w->path
		628
		629	=item $old_path = $w->path ($new_path)
		630
		631	Returns the previously set path and optionally set a new one.
		632
		633	=item $current_interval = $w->interval
		634
		635	=item $old_interval = $w->interval ($new_interval)
		636
		637	Returns the previously set interval and optionally set a new one. Can be
		638	used to query the actual interval used.
		639
		640	=back
		641
		642
		643	=head3 IDLE WATCHERS - when you've got nothing better to do...
		644
		645	=over 4
351		646
352	=item $w = EV::idle $callback	647	=item $w = EV::idle $callback
353		648
354	=item $w = EV::idle_ns $callback	649	=item $w = EV::idle_ns $callback
355		650
356	Call the callback when there are no pending io, timer/periodic, signal or	651	Call the callback when there are no other pending watchers of the same or
357	child events, i.e. when the process is idle.	652	higher priority (excluding check, prepare and other idle watchers of the
		653	same or lower priority, of course). They are called idle watchers because
		654	when the watcher is the highest priority pending event in the process, the
		655	process is considered to be idle at that priority.
		656
		657	If you want a watcher that is only ever called when I<no> other events are
		658	outstanding you have to set the priority to C<EV::MINPRI>.
358		659
359	The process will not block as long as any idle watchers are active, and	660	The process will not block as long as any idle watchers are active, and
360	they will be called repeatedly until stopped.	661	they will be called repeatedly until stopped.
361		662
		663	For example, if you have idle watchers at priority C<0> and C<1>, and
		664	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		665	and the I/O watcher will always run when ready. Only when the idle watcher
		666	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		667	pending with the C<0>-priority idle watcher be invoked.
		668
362	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	669	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
363		670
		671	=back
		672
		673
		674	=head3 PREPARE WATCHERS - customise your event loop!
		675
		676	=over 4
364		677
365	=item $w = EV::prepare $callback	678	=item $w = EV::prepare $callback
366		679
367	=item $w = EV::prepare_ns $callback	680	=item $w = EV::prepare_ns $callback
368		681
…		…
371		684
372	See the EV::check watcher, below, for explanations and an example.	685	See the EV::check watcher, below, for explanations and an example.
373		686
374	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	687	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
375		688
		689	=back
		690
		691
		692	=head3 CHECK WATCHERS - customise your event loop even more!
		693
		694	=over 4
376		695
377	=item $w = EV::check $callback	696	=item $w = EV::check $callback
378		697
379	=item $w = EV::check_ns $callback	698	=item $w = EV::check_ns $callback
380		699
…		…
392	# do nothing unless active	711	# do nothing unless active
393	$dispatcher->{_event_queue_h}	712	$dispatcher->{_event_queue_h}
394	or return;	713	or return;
395		714
396	# make the dispatcher handle any outstanding stuff	715	# make the dispatcher handle any outstanding stuff
		716	... not shown
397		717
398	# create an IO watcher for each and every socket	718	# create an I/O watcher for each and every socket
399	@snmp_watcher = (	719	@snmp_watcher = (
400	(map { EV::io $_, EV::READ, sub { } }	720	(map { EV::io $_, EV::READ, sub { } }
401	keys %{ $dispatcher->{_descriptors} }),	721	keys %{ $dispatcher->{_descriptors} }),
		722
		723	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		724	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		725	0, sub { },
402	);	726	);
403
404	# if there are any timeouts, also create a timer
405	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
406	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
407	};	727	};
408		728
409	The callbacks are irrelevant, the only purpose of those watchers is	729	The callbacks are irrelevant (and are not even being called), the
410	to wake up the process as soon as one of those events occurs (socket	730	only purpose of those watchers is to wake up the process as soon as
411	readable, or timer timed out). The corresponding EV::check watcher will then	731	one of those events occurs (socket readable, or timer timed out). The
412	clean up:	732	corresponding EV::check watcher will then clean up:
413		733
414	our $snmp_check = EV::check sub {	734	our $snmp_check = EV::check sub {
415	# destroy all watchers	735	# destroy all watchers
416	@snmp_watcher = ();	736	@snmp_watcher = ();
417		737
418	# make the dispatcher handle any new stuff	738	# make the dispatcher handle any new stuff
		739	... not shown
419	};	740	};
420		741
421	The callbacks of the created watchers will not be called as the watchers	742	The callbacks of the created watchers will not be called as the watchers
422	are destroyed before this cna happen (remember EV::check gets called	743	are destroyed before this cna happen (remember EV::check gets called
423	first).	744	first).
424		745
425	The C<check_ns> variant doesn't start (activate) the newly created watcher.	746	The C<check_ns> variant doesn't start (activate) the newly created watcher.
426		747
427	=back	748	=back
428		749
		750
		751	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		752
		753	Fork watchers are called when a C<fork ()> was detected. The invocation
		754	is done before the event loop blocks next and before C<check> watchers
		755	are being called, and only in the child after the fork.
		756
		757	=over 4
		758
		759	=item $w = EV::fork $callback
		760
		761	=item $w = EV::fork_ns $callback
		762
		763	Call the callback before the event loop is resumed in the child process
		764	after a fork.
		765
		766	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		767
		768	=back
		769
		770
		771	=head1 PERL SIGNALS
		772
		773	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		774	with EV is as the same as any other C library: Perl-signals will only be
		775	handled when Perl runs, which means your signal handler might be invoked
		776	only the next time an event callback is invoked.
		777
		778	The solution is to use EV signal watchers (see C<EV::signal>), which will
		779	ensure proper operations with regards to other event watchers.
		780
		781	If you cannot do this for whatever reason, you can also force a watcher
		782	to be called on every event loop iteration by installing a C<EV::check>
		783	watcher:
		784
		785	my $async_check = EV::check sub { };
		786
		787	This ensures that perl shortly gets into control for a short time, and
		788	also ensures slower overall operation.
		789
429	=head1 THREADS	790	=head1 THREADS
430		791
431	Threads are not supported by this in any way. Perl pseudo-threads is evil	792	Threads are not supported by this module in any way. Perl pseudo-threads
432	stuff and must die.	793	is evil stuff and must die. As soon as Perl gains real threads I will work
		794	on thread support for it.
		795
		796	=head1 FORK
		797
		798	Most of the "improved" event delivering mechanisms of modern operating
		799	systems have quite a few problems with fork(2) (to put it bluntly: it is
		800	not supported and usually destructive). Libev makes it possible to work
		801	around this by having a function that recreates the kernel state after
		802	fork in the child.
		803
		804	On non-win32 platforms, this module requires the pthread_atfork
		805	functionality to do this automatically for you. This function is quite
		806	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		807	negligible, because everything the function currently does is set a flag
		808	that is checked only when the event loop gets used the next time, so when
		809	you do fork but not use EV, the overhead is minimal.
		810
		811	On win32, there is no notion of fork so all this doesn't apply, of course.
433		812
434	=cut	813	=cut
435		814
436	our $DIED = sub {	815	our $DIED = sub {
437	warn "EV: error in callback (ignoring): $@";	816	warn "EV: error in callback (ignoring): $@";
438	};	817	};
439		818
440	init;	819	default_loop
441		820	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
442	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
443		821
444	1;	822	1;
445		823
446	=head1 SEE ALSO	824	=head1 SEE ALSO
447		825
448	L<EV::DNS>, L<EV::AnyEvent>.	826	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		827	event loop), L<Coro::EV> (efficient coroutines with EV).
449		828
450	=head1 AUTHOR	829	=head1 AUTHOR
451		830
452	Marc Lehmann <schmorp@schmorp.de>	831	Marc Lehmann <schmorp@schmorp.de>
453	http://home.schmorp.de/	832	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs. Revision 1.63 by root, Fri Dec 7 18:11:21 2007 UTC

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Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs.
Revision 1.63 by root, Fri Dec 7 18:11:21 2007 UTC