[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 1.72 by root, Thu Dec 20 07:12:57 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 = '2.0';
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";
		90
		91	@EV::Loop::Default::ISA = "EV::Loop";
78		92
79	=head1 BASIC INTERFACE	93	=head1 BASIC INTERFACE
80		94
81	=over 4	95	=over 4
82		96
83	=item $EV::DIED	97	=item $EV::DIED
84		98
85	Must contain a reference to a function that is called when a callback	99	Must contain a reference to a function that is called when a callback
86	throws an exception (with $@ containing thr error). The default prints an	100	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	101	informative message and continues.
88		102
89	If this callback throws an exception it will be silently ignored.	103	If this callback throws an exception it will be silently ignored.
90		104
91	=item $time = EV::time	105	=item $time = EV::time
…		…
96		110
97	Returns the time the last event loop iteration has been started. This	111	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	112	is the time that (relative) timers are based on, and refering to it is
99	usually faster then calling EV::time.	113	usually faster then calling EV::time.
100		114
101	=item $method = EV::ev_method	115	=item $method = EV::method
102		116
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	117	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
104	or EV::METHOD_EPOLL).	118	or EV::METHOD_EPOLL).
105		119
106	=item EV::loop [$flags]	120	=item EV::loop [$flags]
107		121
108	Begin checking for events and calling callbacks. It returns when a	122	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	123	callback calls EV::unloop.
110		124
111	The $flags argument can be one of the following:	125	The $flags argument can be one of the following:
112		126
113	0 as above	127	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	128	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	129	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		130
117	=item EV::loop_done [$how]	131	=item EV::unloop [$how]
118		132
119	When called with no arguments or an argument of 1, makes the innermost	133	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	134	innermost call to EV::loop return.
121		135
122	When called with an agrument of 2, all calls to EV::loop will return as	136	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	137	fast as possible.
124		138
125	=back	139	=item $count = EV::loop_count
126		140
		141	Return the number of times the event loop has polled for new
		142	events. Sometiems useful as a generation counter.
		143
		144	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		145
		146	This function rolls together an I/O and a timer watcher for a single
		147	one-shot event without the need for managing a watcher object.
		148
		149	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		150	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		151	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		152	you do not want to wait for some I/O event, specify C<undef> for
		153	C<$fh_or_undef> and C<0> for C<$events>).
		154
		155	If timeout is C<undef> or negative, then there will be no
		156	timeout. Otherwise a EV::timer with this value will be started.
		157
		158	When an error occurs or either the timeout or I/O watcher triggers, then
		159	the callback will be called with the received event set (in general
		160	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		161	C<EV::WRITE> and C<EV::TIMEOUT>).
		162
		163	EV::once doesn't return anything: the watchers stay active till either
		164	of them triggers, then they will be stopped and freed, and the callback
		165	invoked.
		166
		167	=item EV::feed_fd_event ($fd, $revents)
		168
		169	Feed an event on a file descriptor into EV. EV will react to this call as
		170	if the readyness notifications specified by C<$revents> (a combination of
		171	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		172
		173	=item EV::feed_signal_event ($signal)
		174
		175	Feed a signal event into EV. EV will react to this call as if the signal
		176	specified by C<$signal> had occured.
		177
		178	=back
		179
		180
127	=head2 WATCHER	181	=head2 WATCHER OBJECTS
128		182
129	A watcher is an object that gets created to record your interest in some	183	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	184	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	185	would create an EV::io watcher for that:
132		186
…		…
141	events.	195	events.
142		196
143	Each watcher type has its associated bit in revents, so you can use the	197	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	198	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,	199	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	200	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	201	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	202	uses EV::TIMEOUT).
149		203
150	In the rare case where one wants to create a watcher but not start it at	204	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	205	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.	206	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
153		207
154	Please note that a watcher will automatically be stopped when the watcher	208	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	209	object is destroyed, so you I<need> to keep the watcher objects returned by
156	the constructors.	210	the constructors.
157		211
158	=head2 WATCHER TYPES	212	Also, all methods changing some aspect of a watcher (->set, ->priority,
		213	->fh and so on) automatically stop and start it again if it is active,
		214	which means pending events get lost.
159		215
160	Now lets move to the existing watcher types and asociated methods.	216	=head2 COMMON WATCHER METHODS
161		217
162	The following methods are available for all watchers. Then followes a	218	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		219
167	=over 4	220	=over 4
168		221
169	=item $w->start	222	=item $w->start
170		223
…		…
174		227
175	=item $w->stop	228	=item $w->stop
176		229
177	Stop a watcher if it is active. Also clear any pending events (events that	230	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),	231	have been received but that didn't yet result in a callback invocation),
179	regardless of wether the watcher was active or not.	232	regardless of whether the watcher was active or not.
180		233
181	=item $bool = $w->is_active	234	=item $bool = $w->is_active
182		235
183	Returns true if the watcher is active, false otherwise.	236	Returns true if the watcher is active, false otherwise.
184		237
		238	=item $current_data = $w->data
		239
		240	=item $old_data = $w->data ($new_data)
		241
		242	Queries a freely usable data scalar on the watcher and optionally changes
		243	it. This is a way to associate custom data with a watcher:
		244
		245	my $w = EV::timer 60, 0, sub {
		246	warn $_[0]->data;
		247	};
		248	$w->data ("print me!");
		249
185	=item $current_cb = $w->cb	250	=item $current_cb = $w->cb
186		251
187	=item $old_cb = $w->cb ($new_cb)	252	=item $old_cb = $w->cb ($new_cb)
188		253
189	Queries the callback on the watcher and optionally changes it. You cna do	254	Queries the callback on the watcher and optionally changes it. You can do
190	this at any time.	255	this at any time without the watcher restarting.
191		256
		257	=item $current_priority = $w->priority
		258
		259	=item $old_priority = $w->priority ($new_priority)
		260
		261	Queries the priority on the watcher and optionally changes it. Pending
		262	watchers with higher priority will be invoked first. The valid range of
		263	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		264	-2). If the priority is outside this range it will automatically be
		265	normalised to the nearest valid priority.
		266
		267	The default priority of any newly-created watcher is 0.
		268
		269	Note that the priority semantics have not yet been fleshed out and are
		270	subject to almost certain change.
		271
192	=item $w->trigger ($revents)	272	=item $w->invoke ($revents)
193		273
194	Call the callback now with the given event mask.	274	Call the callback now with the given event mask.
195		275
		276	=item $w->feed_event ($revents)
		277
		278	Feed some events on this watcher into EV. EV will react to this call as if
		279	the watcher had received the given C<$revents> mask.
		280
		281	=item $revents = $w->clear_pending
		282
		283	If the watcher is pending, this function returns clears its pending status
		284	and returns its C<$revents> bitset (as if its callback was invoked). If the
		285	watcher isn't pending it does nothing and returns C<0>.
		286
		287	=item $previous_state = $w->keepalive ($bool)
		288
		289	Normally, C<EV::loop> will return when there are no active watchers
		290	(which is a "deadlock" because no progress can be made anymore). This is
		291	convinient because it allows you to start your watchers (and your jobs),
		292	call C<EV::loop> once and when it returns you know that all your jobs are
		293	finished (or they forgot to register some watchers for their task :).
		294
		295	Sometimes, however, this gets in your way, for example when you the module
		296	that calls C<EV::loop> (usually the main program) is not the same module
		297	as a long-living watcher (for example a DNS client module written by
		298	somebody else even). Then you might want any outstanding requests to be
		299	handled, but you would not want to keep C<EV::loop> from returning just
		300	because you happen to have this long-running UDP port watcher.
		301
		302	In this case you can clear the keepalive status, which means that even
		303	though your watcher is active, it won't keep C<EV::loop> from returning.
		304
		305	The initial value for keepalive is true (enabled), and you cna change it
		306	any time.
		307
		308	Example: Register an I/O watcher for some UDP socket but do not keep the
		309	event loop from running just because of that watcher.
		310
		311	my $udp_socket = ...
		312	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		313	$udp_watcher->keepalive (0);
		314
		315	=back
		316
		317
		318	=head2 WATCHER TYPES
		319
		320	Each of the following subsections describes a single watcher type.
		321
		322	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		323
		324	=over 4
196		325
197	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	326	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
198		327
199	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	328	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
200		329
201	As long as the returned watcher object is alive, call the C<$callback>	330	As long as the returned watcher object is alive, call the C<$callback>
202	when the events specified in C<$eventmask>.	331	when at least one of events specified in C<$eventmask> occurs.
203		332
204	The $eventmask can be one or more of these constants ORed together:	333	The $eventmask can be one or more of these constants ORed together:
205		334
206	EV::READ wait until read() wouldn't block anymore	335	EV::READ wait until read() wouldn't block anymore
207	EV::WRITE wait until write() wouldn't block anymore	336	EV::WRITE wait until write() wouldn't block anymore
…		…
223		352
224	=item $old_eventmask = $w->events ($new_eventmask)	353	=item $old_eventmask = $w->events ($new_eventmask)
225		354
226	Returns the previously set event mask and optionally set a new one.	355	Returns the previously set event mask and optionally set a new one.
227		356
		357	=back
		358
		359
		360	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		361
		362	=over 4
228		363
229	=item $w = EV::timer $after, $repeat, $callback	364	=item $w = EV::timer $after, $repeat, $callback
230		365
231	=item $w = EV::timer_ns $after, $repeat, $callback	366	=item $w = EV::timer_ns $after, $repeat, $callback
232		367
233	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	368	Calls the callback after C<$after> seconds (which may be fractional). If
234	the timer will be restarted (with the $repeat value as $after) after the	369	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
235	callback returns.	370	value as $after) after the callback returns.
236		371
237	This means that the callback would be called roughly after C<$after>	372	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	373	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	374	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.	375	loop iteration, and might drift in other cases. If that isn't acceptable,
		376	look at EV::periodic, which can provide long-term stable timers.
241		377
242	The timer is based on a monotonic clock, that is if somebody is sitting	378	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	379	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.	380	clock, the timer will nevertheless run (roughly) the same time.
245		381
246	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	382	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
247		383
248	=item $w->set ($after, $repeat)	384	=item $w->set ($after, $repeat)
249		385
250	Reconfigures the watcher, see the constructor above for details. Can be at	386	Reconfigures the watcher, see the constructor above for details. Can be called at
251	any time.	387	any time.
252		388
253	=item $w->again	389	=item $w->again
254		390
255	Similar to the C<start> method, but has special semantics for repeating timers:	391	Similar to the C<start> method, but has special semantics for repeating timers:
		392
		393	If the timer is active and non-repeating, it will be stopped.
256		394
257	If the timer is active and repeating, reset the timeout to occur	395	If the timer is active and repeating, reset the timeout to occur
258	C<$repeat> seconds after now.	396	C<$repeat> seconds after now.
259		397
260	If the timer is active and non-repeating, it will be stopped.
261
262	If the timer is in active and repeating, start it.	398	If the timer is inactive and repeating, start it using the repeat value.
263		399
264	Otherwise do nothing.	400	Otherwise do nothing.
265		401
266	This behaviour is useful when you have a timeout for some IO	402	This behaviour is useful when you have a timeout for some IO
267	operation. You create a timer object with the same value for C<$after> and	403	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	404	C<$repeat>, and then, in the read/write watcher, run the C<again> method
269	on the timeout.	405	on the timeout.
270		406
		407	=back
271		408
		409
		410	=head3 PERIODIC WATCHERS - to cron or not to cron?
		411
		412	=over 4
		413
272	=item $w = EV::periodic $at, $interval, $callback	414	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
273		415
274	=item $w = EV::periodic_ns $at, $interval, $callback	416	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
275		417
276	Similar to EV::timer, but the time is given as an absolute point in time	418	Similar to EV::timer, but is not based on relative timeouts but on
277	(C<$at>), plus an optional C<$interval>.	419	absolute times. Apart from creating "simple" timers that trigger "at" the
		420	specified time, it can also be used for non-drifting absolute timers and
		421	more complex, cron-like, setups that are not adversely affected by time
		422	jumps (i.e. when the system clock is changed by explicit date -s or other
		423	means such as ntpd). It is also the most complex watcher type in EV.
278		424
279	If the C<$interval> is zero, then the callback will be called at the time	425	It has three distinct "modes":
280	C<$at> if that is in the future, or as soon as possible if it is in the
281	past. It will not automatically repeat.
282		426
283	If the C<$interval> is nonzero, then the watcher will always be scheduled	427	=over 4
284	to time out at the next C<$at + N * $interval> time.
285		428
286	This can be used to schedule a callback to run at very regular intervals,	429	=item * absolute timer ($interval = $reschedule_cb = 0)
287	as long as the processing time is less then the interval (otherwise	430
288	obviously events will be skipped).	431	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		432	will not adjust when a time jump occurs, that is, if it is to be run
		433	at January 1st 2011 then it will run when the system time reaches or
		434	surpasses this time.
		435
		436	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		437
		438	In this mode the watcher will always be scheduled to time out at the
		439	next C<$at + N * $interval> time (for some integer N) and then repeat,
		440	regardless of any time jumps.
		441
		442	This can be used to create timers that do not drift with respect to system
		443	time:
		444
		445	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		446
		447	That doesn't mean there will always be 3600 seconds in between triggers,
		448	but only that the the clalback will be called when the system time shows a
		449	full hour (UTC).
289		450
290	Another way to think about it (for the mathematically inclined) is that	451	Another way to think about it (for the mathematically inclined) is that
291	EV::periodic will try to run the callback at the next possible time where	452	EV::periodic will try to run the callback in this mode at the next
292	C<$time = $at (mod $interval)>, regardless of any time jumps.	453	possible time where C<$time = $at (mod $interval)>, regardless of any time
		454	jumps.
293		455
294	This periodic timer is based on "wallclock time", that is, if the clock	456	=item * manual reschedule mode ($reschedule_cb = coderef)
295	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	457
296	the specified time. This means it will never drift (it might jitter, but	458	In this mode $interval and $at are both being ignored. Instead, each
297	it will not drift).	459	time the periodic watcher gets scheduled, the reschedule callback
		460	($reschedule_cb) will be called with the watcher as first, and the current
		461	time as second argument.
		462
		463	I<This callback MUST NOT stop or destroy this or any other periodic
		464	watcher, ever>. If you need to stop it, return 1e30 and stop it
		465	afterwards.
		466
		467	It must return the next time to trigger, based on the passed time value
		468	(that is, the lowest time value larger than to the second argument). It
		469	will usually be called just before the callback will be triggered, but
		470	might be called at other times, too.
		471
		472	This can be used to create very complex timers, such as a timer that
		473	triggers on each midnight, local time (actually 24 hours after the last
		474	midnight, to keep the example simple. If you know a way to do it correctly
		475	in about the same space (without requiring elaborate modules), drop me a
		476	note :):
		477
		478	my $daily = EV::periodic 0, 0, sub {
		479	my ($w, $now) = @_;
		480
		481	use Time::Local ();
		482	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		483	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		484	}, sub {
		485	print "it's midnight or likely shortly after, now\n";
		486	};
		487
		488	=back
298		489
299	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	490	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
300		491
301	=item $w->set ($at, $interval)	492	=item $w->set ($at, $interval, $reschedule_cb)
302		493
303	Reconfigures the watcher, see the constructor above for details. Can be at	494	Reconfigures the watcher, see the constructor above for details. Can be called at
304	any time.	495	any time.
305		496
		497	=item $w->again
		498
		499	Simply stops and starts the watcher again.
		500
		501	=item $time = $w->at
		502
		503	Return the time that the watcher is expected to trigger next.
		504
		505	=back
		506
		507
		508	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		509
		510	=over 4
306		511
307	=item $w = EV::signal $signal, $callback	512	=item $w = EV::signal $signal, $callback
308		513
309	=item $w = EV::signal_ns $signal, $callback	514	=item $w = EV::signal_ns $signal, $callback
310		515
311	Call the callback when $signal is received (the signal can be specified	516	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).	517	number or by name, just as with C<kill> or C<%SIG>).
313		518
314	EV will grab the signal for the process (the kernel only allows one	519	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,	520	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	521	and removes it again when you stop it. Perl does the same when you
317	add/remove callbacks to %SIG, so watch out.	522	add/remove callbacks to C<%SIG>, so watch out.
318		523
319	You can have as many signal watchers per signal as you want.	524	You can have as many signal watchers per signal as you want.
320		525
321	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	526	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
322		527
323	=item $w->set ($signal)	528	=item $w->set ($signal)
324		529
325	Reconfigures the watcher, see the constructor above for details. Can be at	530	Reconfigures the watcher, see the constructor above for details. Can be
326	any time.	531	called at any time.
327		532
328	=item $current_signum = $w->signal	533	=item $current_signum = $w->signal
329		534
330	=item $old_signum = $w->signal ($new_signal)	535	=item $old_signum = $w->signal ($new_signal)
331		536
332	Returns the previously set signal (always as a number not name) and	537	Returns the previously set signal (always as a number not name) and
333	optionally set a new one.	538	optionally set a new one.
334		539
		540	=back
		541
		542
		543	=head3 CHILD WATCHERS - watch out for process status changes
		544
		545	=over 4
335		546
336	=item $w = EV::child $pid, $callback	547	=item $w = EV::child $pid, $callback
337		548
338	=item $w = EV::child_ns $pid, $callback	549	=item $w = EV::child_ns $pid, $callback
339		550
340	Call the callback when a status change for pid C<$pid> (or any pid	551	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	552	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	553	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
343	changed/zombie children and call the callback.	554	changed/zombie children and call the callback.
344		555
345	Unlike all other callbacks, this callback will be called with an	556	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>	557	has exited but before the event loop has started its next iteration (for
347	function for details.	558	example, first you C<fork>, then the new child process might exit, and
		559	only then do you install a child watcher in the parent for the new pid).
348		560
		561	You can access both exit (or tracing) status and pid by using the
		562	C<rstatus> and C<rpid> methods on the watcher object.
		563
349	You can have as many pid watchers per pid as you want.	564	You can have as many pid watchers per pid as you want, they will all be
		565	called.
350		566
351	The C<child_ns> variant doesn't start (activate) the newly created watcher.	567	The C<child_ns> variant doesn't start (activate) the newly created watcher.
352		568
353	=item $w->set ($pid)	569	=item $w->set ($pid)
354		570
355	Reconfigures the watcher, see the constructor above for details. Can be at	571	Reconfigures the watcher, see the constructor above for details. Can be called at
356	any time.	572	any time.
357		573
358	=item $current_pid = $w->pid	574	=item $current_pid = $w->pid
359		575
360	=item $old_pid = $w->pid ($new_pid)	576	=item $old_pid = $w->pid ($new_pid)
361		577
362	Returns the previously set process id and optionally set a new one.	578	Returns the previously set process id and optionally set a new one.
363		579
		580	=item $exit_status = $w->rstatus
		581
		582	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		583	in perlfunc).
		584
		585	=item $pid = $w->rpid
		586
		587	Return the pid of the awaited child (useful when you have installed a
		588	watcher for all pids).
		589
		590	=back
		591
		592
		593	=head3 STAT WATCHERS - did the file attributes just change?
		594
		595	=over 4
		596
		597	=item $w = EV::stat $path, $interval, $callback
		598
		599	=item $w = EV::stat_ns $path, $interval, $callback
		600
		601	Call the callback when a file status change has been detected on
		602	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		603	to "path does not exist" is a status change like any other.
		604
		605	The C<$interval> is a recommended polling interval for systems where
		606	OS-supported change notifications don't exist or are not supported. If
		607	you use C<0> then an unspecified default is used (which is highly
		608	recommended!), which is to be expected to be around five seconds usually.
		609
		610	This watcher type is not meant for massive numbers of stat watchers,
		611	as even with OS-supported change notifications, this can be
		612	resource-intensive.
		613
		614	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		615
		616	=item ... = $w->stat
		617
		618	This call is very similar to the perl C<stat> built-in: It stats (using
		619	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		620	well as EV's idea of the current stat values) to the values found.
		621
		622	In scalar context, a boolean is return indicating success or failure of
		623	the stat. In list context, the same 13-value list as with stat is returned
		624	(except that the blksize and blocks fields are not reliable).
		625
		626	In the case of an error, errno is set to C<ENOENT> (regardless of the
		627	actual error value) and the C<nlink> value is forced to zero (if the stat
		628	was successful then nlink is guaranteed to be non-zero).
		629
		630	See also the next two entries for more info.
		631
		632	=item ... = $w->attr
		633
		634	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		635	the values most recently detected by EV. See the next entry for more info.
		636
		637	=item ... = $w->prev
		638
		639	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		640	the previous set of values, before the change.
		641
		642	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		643	to the values found I<before> a change was detected, while C<< $w->attr >>
		644	returns the values found leading to the change detection. The difference (if any)
		645	between C<prev> and C<attr> is what triggered the callback.
		646
		647	If you did something to the filesystem object and do not want to trigger
		648	yet another change, you can call C<stat> to update EV's idea of what the
		649	current attributes are.
		650
		651	=item $w->set ($path, $interval)
		652
		653	Reconfigures the watcher, see the constructor above for details. Can be
		654	called at any time.
		655
		656	=item $current_path = $w->path
		657
		658	=item $old_path = $w->path ($new_path)
		659
		660	Returns the previously set path and optionally set a new one.
		661
		662	=item $current_interval = $w->interval
		663
		664	=item $old_interval = $w->interval ($new_interval)
		665
		666	Returns the previously set interval and optionally set a new one. Can be
		667	used to query the actual interval used.
		668
		669	=back
		670
		671
		672	=head3 IDLE WATCHERS - when you've got nothing better to do...
		673
		674	=over 4
364		675
365	=item $w = EV::idle $callback	676	=item $w = EV::idle $callback
366		677
367	=item $w = EV::idle_ns $callback	678	=item $w = EV::idle_ns $callback
368		679
369	Call the callback when there are no pending io, timer/periodic, signal or	680	Call the callback when there are no other pending watchers of the same or
370	child events, i.e. when the process is idle.	681	higher priority (excluding check, prepare and other idle watchers of the
		682	same or lower priority, of course). They are called idle watchers because
		683	when the watcher is the highest priority pending event in the process, the
		684	process is considered to be idle at that priority.
		685
		686	If you want a watcher that is only ever called when I<no> other events are
		687	outstanding you have to set the priority to C<EV::MINPRI>.
371		688
372	The process will not block as long as any idle watchers are active, and	689	The process will not block as long as any idle watchers are active, and
373	they will be called repeatedly until stopped.	690	they will be called repeatedly until stopped.
374		691
		692	For example, if you have idle watchers at priority C<0> and C<1>, and
		693	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		694	and the I/O watcher will always run when ready. Only when the idle watcher
		695	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		696	pending with the C<0>-priority idle watcher be invoked.
		697
375	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	698	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
376		699
		700	=back
		701
		702
		703	=head3 PREPARE WATCHERS - customise your event loop!
		704
		705	=over 4
377		706
378	=item $w = EV::prepare $callback	707	=item $w = EV::prepare $callback
379		708
380	=item $w = EV::prepare_ns $callback	709	=item $w = EV::prepare_ns $callback
381		710
…		…
384		713
385	See the EV::check watcher, below, for explanations and an example.	714	See the EV::check watcher, below, for explanations and an example.
386		715
387	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	716	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
388		717
		718	=back
		719
		720
		721	=head3 CHECK WATCHERS - customise your event loop even more!
		722
		723	=over 4
389		724
390	=item $w = EV::check $callback	725	=item $w = EV::check $callback
391		726
392	=item $w = EV::check_ns $callback	727	=item $w = EV::check_ns $callback
393		728
…		…
405	# do nothing unless active	740	# do nothing unless active
406	$dispatcher->{_event_queue_h}	741	$dispatcher->{_event_queue_h}
407	or return;	742	or return;
408		743
409	# make the dispatcher handle any outstanding stuff	744	# make the dispatcher handle any outstanding stuff
		745	... not shown
410		746
411	# create an IO watcher for each and every socket	747	# create an I/O watcher for each and every socket
412	@snmp_watcher = (	748	@snmp_watcher = (
413	(map { EV::io $_, EV::READ, sub { } }	749	(map { EV::io $_, EV::READ, sub { } }
414	keys %{ $dispatcher->{_descriptors} }),	750	keys %{ $dispatcher->{_descriptors} }),
		751
		752	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		753	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		754	0, sub { },
415	);	755	);
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	};	756	};
421		757
422	The callbacks are irrelevant, the only purpose of those watchers is	758	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	759	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	760	one of those events occurs (socket readable, or timer timed out). The
425	clean up:	761	corresponding EV::check watcher will then clean up:
426		762
427	our $snmp_check = EV::check sub {	763	our $snmp_check = EV::check sub {
428	# destroy all watchers	764	# destroy all watchers
429	@snmp_watcher = ();	765	@snmp_watcher = ();
430		766
431	# make the dispatcher handle any new stuff	767	# make the dispatcher handle any new stuff
		768	... not shown
432	};	769	};
433		770
434	The callbacks of the created watchers will not be called as the watchers	771	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	772	are destroyed before this cna happen (remember EV::check gets called
436	first).	773	first).
437		774
438	The C<check_ns> variant doesn't start (activate) the newly created watcher.	775	The C<check_ns> variant doesn't start (activate) the newly created watcher.
439		776
440	=back	777	=back
441		778
		779
		780	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		781
		782	Fork watchers are called when a C<fork ()> was detected. The invocation
		783	is done before the event loop blocks next and before C<check> watchers
		784	are being called, and only in the child after the fork.
		785
		786	=over 4
		787
		788	=item $w = EV::fork $callback
		789
		790	=item $w = EV::fork_ns $callback
		791
		792	Call the callback before the event loop is resumed in the child process
		793	after a fork.
		794
		795	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		796
		797	=back
		798
		799
		800	=head1 PERL SIGNALS
		801
		802	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		803	with EV is as the same as any other C library: Perl-signals will only be
		804	handled when Perl runs, which means your signal handler might be invoked
		805	only the next time an event callback is invoked.
		806
		807	The solution is to use EV signal watchers (see C<EV::signal>), which will
		808	ensure proper operations with regards to other event watchers.
		809
		810	If you cannot do this for whatever reason, you can also force a watcher
		811	to be called on every event loop iteration by installing a C<EV::check>
		812	watcher:
		813
		814	my $async_check = EV::check sub { };
		815
		816	This ensures that perl shortly gets into control for a short time, and
		817	also ensures slower overall operation.
		818
442	=head1 THREADS	819	=head1 THREADS
443		820
444	Threads are not supported by this in any way. Perl pseudo-threads is evil	821	Threads are not supported by this module in any way. Perl pseudo-threads
445	stuff and must die.	822	is evil stuff and must die. As soon as Perl gains real threads I will work
		823	on thread support for it.
		824
		825	=head1 FORK
		826
		827	Most of the "improved" event delivering mechanisms of modern operating
		828	systems have quite a few problems with fork(2) (to put it bluntly: it is
		829	not supported and usually destructive). Libev makes it possible to work
		830	around this by having a function that recreates the kernel state after
		831	fork in the child.
		832
		833	On non-win32 platforms, this module requires the pthread_atfork
		834	functionality to do this automatically for you. This function is quite
		835	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		836	negligible, because everything the function currently does is set a flag
		837	that is checked only when the event loop gets used the next time, so when
		838	you do fork but not use EV, the overhead is minimal.
		839
		840	On win32, there is no notion of fork so all this doesn't apply, of course.
446		841
447	=cut	842	=cut
448		843
449	our $DIED = sub {	844	our $DIED = sub {
450	warn "EV: error in callback (ignoring): $@";	845	warn "EV: error in callback (ignoring): $@";
451	};	846	};
452		847
453	init;	848	default_loop
454		849	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
455	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
456		850
457	1;	851	1;
458		852
459	=head1 SEE ALSO	853	=head1 SEE ALSO
460		854
461	L<EV::DNS>, L<EV::AnyEvent>.	855	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		856	event loop), L<Coro::EV> (efficient coroutines with EV).
462		857
463	=head1 AUTHOR	858	=head1 AUTHOR
464		859
465	Marc Lehmann <schmorp@schmorp.de>	860	Marc Lehmann <schmorp@schmorp.de>
466	http://home.schmorp.de/	861	http://home.schmorp.de/

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Revision 1.72 by root, Thu Dec 20 07:12:57 2007 UTC