[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 1.67 by root, Sun Dec 9 02:14:23 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 = '1.72';
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
83	=item $EV::DIED	95	=item $EV::DIED
84		96
85	Must contain a reference to a function that is called when a callback	97	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	98	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	99	informative message and continues.
88		100
89	If this callback throws an exception it will be silently ignored.	101	If this callback throws an exception it will be silently ignored.
90		102
91	=item $time = EV::time	103	=item $time = EV::time
…		…
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	=item EV::feed_fd_event ($fd, $revents)
		166
		167	Feed an event on a file descriptor into EV. EV will react to this call as
		168	if the readyness notifications specified by C<$revents> (a combination of
		169	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		170
		171	=item EV::feed_signal_event ($signal)
		172
		173	Feed a signal event into EV. EV will react to this call as if the signal
		174	specified by C<$signal> had occured.
		175
		176	=back
		177
		178
127	=head2 WATCHER	179	=head2 WATCHER OBJECTS
128		180
129	A watcher is an object that gets created to record your interest in some	181	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	182	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	183	would create an EV::io watcher for that:
132		184
…		…
141	events.	193	events.
142		194
143	Each watcher type has its associated bit in revents, so you can use the	195	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	196	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,	197	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	198	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	199	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	200	uses EV::TIMEOUT).
149		201
150	In the rare case where one wants to create a watcher but not start it at	202	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	203	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.	204	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
153		205
154	Please note that a watcher will automatically be stopped when the watcher	206	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	207	object is destroyed, so you I<need> to keep the watcher objects returned by
156	the constructors.	208	the constructors.
157		209
158	=head2 WATCHER TYPES	210	Also, all methods changing some aspect of a watcher (->set, ->priority,
		211	->fh and so on) automatically stop and start it again if it is active,
		212	which means pending events get lost.
159		213
160	Now lets move to the existing watcher types and asociated methods.	214	=head2 COMMON WATCHER METHODS
161		215
162	The following methods are available for all watchers. Then followes a	216	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		217
167	=over 4	218	=over 4
168		219
169	=item $w->start	220	=item $w->start
170		221
…		…
174		225
175	=item $w->stop	226	=item $w->stop
176		227
177	Stop a watcher if it is active. Also clear any pending events (events that	228	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),	229	have been received but that didn't yet result in a callback invocation),
179	regardless of wether the watcher was active or not.	230	regardless of whether the watcher was active or not.
180		231
181	=item $bool = $w->is_active	232	=item $bool = $w->is_active
182		233
183	Returns true if the watcher is active, false otherwise.	234	Returns true if the watcher is active, false otherwise.
184		235
		236	=item $current_data = $w->data
		237
		238	=item $old_data = $w->data ($new_data)
		239
		240	Queries a freely usable data scalar on the watcher and optionally changes
		241	it. This is a way to associate custom data with a watcher:
		242
		243	my $w = EV::timer 60, 0, sub {
		244	warn $_[0]->data;
		245	};
		246	$w->data ("print me!");
		247
185	=item $current_cb = $w->cb	248	=item $current_cb = $w->cb
186		249
187	=item $old_cb = $w->cb ($new_cb)	250	=item $old_cb = $w->cb ($new_cb)
188		251
189	Queries the callback on the watcher and optionally changes it. You cna do	252	Queries the callback on the watcher and optionally changes it. You can do
190	this at any time.	253	this at any time without the watcher restarting.
191		254
		255	=item $current_priority = $w->priority
		256
		257	=item $old_priority = $w->priority ($new_priority)
		258
		259	Queries the priority on the watcher and optionally changes it. Pending
		260	watchers with higher priority will be invoked first. The valid range of
		261	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		262	-2). If the priority is outside this range it will automatically be
		263	normalised to the nearest valid priority.
		264
		265	The default priority of any newly-created watcher is 0.
		266
		267	Note that the priority semantics have not yet been fleshed out and are
		268	subject to almost certain change.
		269
192	=item $w->trigger ($revents)	270	=item $w->invoke ($revents)
193		271
194	Call the callback now with the given event mask.	272	Call the callback now with the given event mask.
195		273
		274	=item $w->feed_event ($revents)
		275
		276	Feed some events on this watcher into EV. EV will react to this call as if
		277	the watcher had received the given C<$revents> mask.
		278
		279	=item $revents = $w->clear_pending
		280
		281	If the watcher is pending, this function returns clears its pending status
		282	and returns its C<$revents> bitset (as if its callback was invoked). If the
		283	watcher isn't pending it does nothing and returns C<0>.
		284
		285	=item $previous_state = $w->keepalive ($bool)
		286
		287	Normally, C<EV::loop> will return when there are no active watchers
		288	(which is a "deadlock" because no progress can be made anymore). This is
		289	convinient because it allows you to start your watchers (and your jobs),
		290	call C<EV::loop> once and when it returns you know that all your jobs are
		291	finished (or they forgot to register some watchers for their task :).
		292
		293	Sometimes, however, this gets in your way, for example when you the module
		294	that calls C<EV::loop> (usually the main program) is not the same module
		295	as a long-living watcher (for example a DNS client module written by
		296	somebody else even). Then you might want any outstanding requests to be
		297	handled, but you would not want to keep C<EV::loop> from returning just
		298	because you happen to have this long-running UDP port watcher.
		299
		300	In this case you can clear the keepalive status, which means that even
		301	though your watcher is active, it won't keep C<EV::loop> from returning.
		302
		303	The initial value for keepalive is true (enabled), and you cna change it
		304	any time.
		305
		306	Example: Register an I/O watcher for some UDP socket but do not keep the
		307	event loop from running just because of that watcher.
		308
		309	my $udp_socket = ...
		310	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		311	$udp_watcher->keepalive (0);
		312
		313	=back
		314
		315
		316	=head2 WATCHER TYPES
		317
		318	Each of the following subsections describes a single watcher type.
		319
		320	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		321
		322	=over 4
196		323
197	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	324	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
198		325
199	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	326	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
200		327
201	As long as the returned watcher object is alive, call the C<$callback>	328	As long as the returned watcher object is alive, call the C<$callback>
202	when the events specified in C<$eventmask>.	329	when at least one of events specified in C<$eventmask> occurs.
203		330
204	The $eventmask can be one or more of these constants ORed together:	331	The $eventmask can be one or more of these constants ORed together:
205		332
206	EV::READ wait until read() wouldn't block anymore	333	EV::READ wait until read() wouldn't block anymore
207	EV::WRITE wait until write() wouldn't block anymore	334	EV::WRITE wait until write() wouldn't block anymore
…		…
223		350
224	=item $old_eventmask = $w->events ($new_eventmask)	351	=item $old_eventmask = $w->events ($new_eventmask)
225		352
226	Returns the previously set event mask and optionally set a new one.	353	Returns the previously set event mask and optionally set a new one.
227		354
		355	=back
		356
		357
		358	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		359
		360	=over 4
228		361
229	=item $w = EV::timer $after, $repeat, $callback	362	=item $w = EV::timer $after, $repeat, $callback
230		363
231	=item $w = EV::timer_ns $after, $repeat, $callback	364	=item $w = EV::timer_ns $after, $repeat, $callback
232		365
233	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	366	Calls the callback after C<$after> seconds (which may be fractional). If
234	the timer will be restarted (with the $repeat value as $after) after the	367	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
235	callback returns.	368	value as $after) after the callback returns.
236		369
237	This means that the callback would be called roughly after C<$after>	370	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	371	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	372	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.	373	loop iteration, and might drift in other cases. If that isn't acceptable,
		374	look at EV::periodic, which can provide long-term stable timers.
241		375
242	The timer is based on a monotonic clock, that is if somebody is sitting	376	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	377	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.	378	clock, the timer will nevertheless run (roughly) the same time.
245		379
246	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	380	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
247		381
248	=item $w->set ($after, $repeat)	382	=item $w->set ($after, $repeat)
249		383
250	Reconfigures the watcher, see the constructor above for details. Can be at	384	Reconfigures the watcher, see the constructor above for details. Can be called at
251	any time.	385	any time.
252		386
253	=item $w->again	387	=item $w->again
254		388
255	Similar to the C<start> method, but has special semantics for repeating timers:	389	Similar to the C<start> method, but has special semantics for repeating timers:
		390
		391	If the timer is active and non-repeating, it will be stopped.
256		392
257	If the timer is active and repeating, reset the timeout to occur	393	If the timer is active and repeating, reset the timeout to occur
258	C<$repeat> seconds after now.	394	C<$repeat> seconds after now.
259		395
260	If the timer is active and non-repeating, it will be stopped.
261
262	If the timer is in active and repeating, start it.	396	If the timer is inactive and repeating, start it using the repeat value.
263		397
264	Otherwise do nothing.	398	Otherwise do nothing.
265		399
266	This behaviour is useful when you have a timeout for some IO	400	This behaviour is useful when you have a timeout for some IO
267	operation. You create a timer object with the same value for C<$after> and	401	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	402	C<$repeat>, and then, in the read/write watcher, run the C<again> method
269	on the timeout.	403	on the timeout.
270		404
		405	=back
271		406
		407
		408	=head3 PERIODIC WATCHERS - to cron or not to cron?
		409
		410	=over 4
		411
272	=item $w = EV::periodic $at, $interval, $callback	412	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
273		413
274	=item $w = EV::periodic_ns $at, $interval, $callback	414	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
275		415
276	Similar to EV::timer, but the time is given as an absolute point in time	416	Similar to EV::timer, but is not based on relative timeouts but on
277	(C<$at>), plus an optional C<$interval>.	417	absolute times. Apart from creating "simple" timers that trigger "at" the
		418	specified time, it can also be used for non-drifting absolute timers and
		419	more complex, cron-like, setups that are not adversely affected by time
		420	jumps (i.e. when the system clock is changed by explicit date -s or other
		421	means such as ntpd). It is also the most complex watcher type in EV.
278		422
279	If the C<$interval> is zero, then the callback will be called at the time	423	It has three distinct "modes":
280	C<$at> if that is in the future, or as soon as possible if it is in the
281	past. It will not automatically repeat.
282		424
283	If the C<$interval> is nonzero, then the watcher will always be scheduled	425	=over 4
284	to time out at the next C<$at + N * $interval> time.
285		426
286	This can be used to schedule a callback to run at very regular intervals,	427	=item * absolute timer ($interval = $reschedule_cb = 0)
287	as long as the processing time is less then the interval (otherwise	428
288	obviously events will be skipped).	429	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		430	will not adjust when a time jump occurs, that is, if it is to be run
		431	at January 1st 2011 then it will run when the system time reaches or
		432	surpasses this time.
		433
		434	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		435
		436	In this mode the watcher will always be scheduled to time out at the
		437	next C<$at + N * $interval> time (for some integer N) and then repeat,
		438	regardless of any time jumps.
		439
		440	This can be used to create timers that do not drift with respect to system
		441	time:
		442
		443	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		444
		445	That doesn't mean there will always be 3600 seconds in between triggers,
		446	but only that the the clalback will be called when the system time shows a
		447	full hour (UTC).
289		448
290	Another way to think about it (for the mathematically inclined) is that	449	Another way to think about it (for the mathematically inclined) is that
291	EV::periodic will try to run the callback at the next possible time where	450	EV::periodic will try to run the callback in this mode at the next
292	C<$time = $at (mod $interval)>, regardless of any time jumps.	451	possible time where C<$time = $at (mod $interval)>, regardless of any time
		452	jumps.
293		453
294	This periodic timer is based on "wallclock time", that is, if the clock	454	=item * manual reschedule mode ($reschedule_cb = coderef)
295	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	455
296	the specified time. This means it will never drift (it might jitter, but	456	In this mode $interval and $at are both being ignored. Instead, each
297	it will not drift).	457	time the periodic watcher gets scheduled, the reschedule callback
		458	($reschedule_cb) will be called with the watcher as first, and the current
		459	time as second argument.
		460
		461	I<This callback MUST NOT stop or destroy this or any other periodic
		462	watcher, ever>. If you need to stop it, return 1e30 and stop it
		463	afterwards.
		464
		465	It must return the next time to trigger, based on the passed time value
		466	(that is, the lowest time value larger than to the second argument). It
		467	will usually be called just before the callback will be triggered, but
		468	might be called at other times, too.
		469
		470	This can be used to create very complex timers, such as a timer that
		471	triggers on each midnight, local time (actually 24 hours after the last
		472	midnight, to keep the example simple. If you know a way to do it correctly
		473	in about the same space (without requiring elaborate modules), drop me a
		474	note :):
		475
		476	my $daily = EV::periodic 0, 0, sub {
		477	my ($w, $now) = @_;
		478
		479	use Time::Local ();
		480	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		481	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		482	}, sub {
		483	print "it's midnight or likely shortly after, now\n";
		484	};
		485
		486	=back
298		487
299	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	488	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
300		489
301	=item $w->set ($at, $interval)	490	=item $w->set ($at, $interval, $reschedule_cb)
302		491
303	Reconfigures the watcher, see the constructor above for details. Can be at	492	Reconfigures the watcher, see the constructor above for details. Can be called at
304	any time.	493	any time.
305		494
		495	=item $w->again
		496
		497	Simply stops and starts the watcher again.
		498
		499	=back
		500
		501
		502	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		503
		504	=over 4
306		505
307	=item $w = EV::signal $signal, $callback	506	=item $w = EV::signal $signal, $callback
308		507
309	=item $w = EV::signal_ns $signal, $callback	508	=item $w = EV::signal_ns $signal, $callback
310		509
311	Call the callback when $signal is received (the signal can be specified	510	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).	511	number or by name, just as with C<kill> or C<%SIG>).
313		512
314	EV will grab the signal for the process (the kernel only allows one	513	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,	514	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	515	and removes it again when you stop it. Perl does the same when you
317	add/remove callbacks to %SIG, so watch out.	516	add/remove callbacks to C<%SIG>, so watch out.
318		517
319	You can have as many signal watchers per signal as you want.	518	You can have as many signal watchers per signal as you want.
320		519
321	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	520	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
322		521
323	=item $w->set ($signal)	522	=item $w->set ($signal)
324		523
325	Reconfigures the watcher, see the constructor above for details. Can be at	524	Reconfigures the watcher, see the constructor above for details. Can be
326	any time.	525	called at any time.
327		526
328	=item $current_signum = $w->signal	527	=item $current_signum = $w->signal
329		528
330	=item $old_signum = $w->signal ($new_signal)	529	=item $old_signum = $w->signal ($new_signal)
331		530
332	Returns the previously set signal (always as a number not name) and	531	Returns the previously set signal (always as a number not name) and
333	optionally set a new one.	532	optionally set a new one.
334		533
		534	=back
		535
		536
		537	=head3 CHILD WATCHERS - watch out for process status changes
		538
		539	=over 4
335		540
336	=item $w = EV::child $pid, $callback	541	=item $w = EV::child $pid, $callback
337		542
338	=item $w = EV::child_ns $pid, $callback	543	=item $w = EV::child_ns $pid, $callback
339		544
340	Call the callback when a status change for pid C<$pid> (or any pid	545	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	546	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	547	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
343	changed/zombie children and call the callback.	548	changed/zombie children and call the callback.
344		549
345	Unlike all other callbacks, this callback will be called with an	550	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>	551	has exited but before the event loop has started its next iteration (for
347	function for details.	552	example, first you C<fork>, then the new child process might exit, and
		553	only then do you install a child watcher in the parent for the new pid).
348		554
		555	You can access both exit (or tracing) status and pid by using the
		556	C<rstatus> and C<rpid> methods on the watcher object.
		557
349	You can have as many pid watchers per pid as you want.	558	You can have as many pid watchers per pid as you want, they will all be
		559	called.
350		560
351	The C<child_ns> variant doesn't start (activate) the newly created watcher.	561	The C<child_ns> variant doesn't start (activate) the newly created watcher.
352		562
353	=item $w->set ($pid)	563	=item $w->set ($pid)
354		564
355	Reconfigures the watcher, see the constructor above for details. Can be at	565	Reconfigures the watcher, see the constructor above for details. Can be called at
356	any time.	566	any time.
357		567
358	=item $current_pid = $w->pid	568	=item $current_pid = $w->pid
359		569
360	=item $old_pid = $w->pid ($new_pid)	570	=item $old_pid = $w->pid ($new_pid)
361		571
362	Returns the previously set process id and optionally set a new one.	572	Returns the previously set process id and optionally set a new one.
363		573
		574	=item $exit_status = $w->rstatus
		575
		576	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		577	in perlfunc).
		578
		579	=item $pid = $w->rpid
		580
		581	Return the pid of the awaited child (useful when you have installed a
		582	watcher for all pids).
		583
		584	=back
		585
		586
		587	=head3 STAT WATCHERS - did the file attributes just change?
		588
		589	=over 4
		590
		591	=item $w = EV::stat $path, $interval, $callback
		592
		593	=item $w = EV::stat_ns $path, $interval, $callback
		594
		595	Call the callback when a file status change has been detected on
		596	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		597	to "path does not exist" is a status change like any other.
		598
		599	The C<$interval> is a recommended polling interval for systems where
		600	OS-supported change notifications don't exist or are not supported. If
		601	you use C<0> then an unspecified default is used (which is highly
		602	recommended!), which is to be expected to be around five seconds usually.
		603
		604	This watcher type is not meant for massive numbers of stat watchers,
		605	as even with OS-supported change notifications, this can be
		606	resource-intensive.
		607
		608	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		609
		610	=item ... = $w->stat
		611
		612	This call is very similar to the perl C<stat> built-in: It stats (using
		613	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		614	well as EV's idea of the current stat values) to the values found.
		615
		616	In scalar context, a boolean is return indicating success or failure of
		617	the stat. In list context, the same 13-value list as with stat is returned
		618	(except that the blksize and blocks fields are not reliable).
		619
		620	In the case of an error, errno is set to C<ENOENT> (regardless of the
		621	actual error value) and the C<nlink> value is forced to zero (if the stat
		622	was successful then nlink is guaranteed to be non-zero).
		623
		624	See also the next two entries for more info.
		625
		626	=item ... = $w->attr
		627
		628	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		629	the values most recently detected by EV. See the next entry for more info.
		630
		631	=item ... = $w->prev
		632
		633	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		634	the previous set of values, before the change.
		635
		636	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		637	to the values found I<before> a change was detected, while C<< $w->attr >>
		638	returns the values found leading to the change detection. The difference (if any)
		639	between C<prev> and C<attr> is what triggered the callback.
		640
		641	If you did something to the filesystem object and do not want to trigger
		642	yet another change, you can call C<stat> to update EV's idea of what the
		643	current attributes are.
		644
		645	=item $w->set ($path, $interval)
		646
		647	Reconfigures the watcher, see the constructor above for details. Can be
		648	called at any time.
		649
		650	=item $current_path = $w->path
		651
		652	=item $old_path = $w->path ($new_path)
		653
		654	Returns the previously set path and optionally set a new one.
		655
		656	=item $current_interval = $w->interval
		657
		658	=item $old_interval = $w->interval ($new_interval)
		659
		660	Returns the previously set interval and optionally set a new one. Can be
		661	used to query the actual interval used.
		662
		663	=back
		664
		665
		666	=head3 IDLE WATCHERS - when you've got nothing better to do...
		667
		668	=over 4
364		669
365	=item $w = EV::idle $callback	670	=item $w = EV::idle $callback
366		671
367	=item $w = EV::idle_ns $callback	672	=item $w = EV::idle_ns $callback
368		673
369	Call the callback when there are no pending io, timer/periodic, signal or	674	Call the callback when there are no other pending watchers of the same or
370	child events, i.e. when the process is idle.	675	higher priority (excluding check, prepare and other idle watchers of the
		676	same or lower priority, of course). They are called idle watchers because
		677	when the watcher is the highest priority pending event in the process, the
		678	process is considered to be idle at that priority.
		679
		680	If you want a watcher that is only ever called when I<no> other events are
		681	outstanding you have to set the priority to C<EV::MINPRI>.
371		682
372	The process will not block as long as any idle watchers are active, and	683	The process will not block as long as any idle watchers are active, and
373	they will be called repeatedly until stopped.	684	they will be called repeatedly until stopped.
374		685
		686	For example, if you have idle watchers at priority C<0> and C<1>, and
		687	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		688	and the I/O watcher will always run when ready. Only when the idle watcher
		689	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		690	pending with the C<0>-priority idle watcher be invoked.
		691
375	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	692	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
376		693
		694	=back
		695
		696
		697	=head3 PREPARE WATCHERS - customise your event loop!
		698
		699	=over 4
377		700
378	=item $w = EV::prepare $callback	701	=item $w = EV::prepare $callback
379		702
380	=item $w = EV::prepare_ns $callback	703	=item $w = EV::prepare_ns $callback
381		704
…		…
384		707
385	See the EV::check watcher, below, for explanations and an example.	708	See the EV::check watcher, below, for explanations and an example.
386		709
387	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	710	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
388		711
		712	=back
		713
		714
		715	=head3 CHECK WATCHERS - customise your event loop even more!
		716
		717	=over 4
389		718
390	=item $w = EV::check $callback	719	=item $w = EV::check $callback
391		720
392	=item $w = EV::check_ns $callback	721	=item $w = EV::check_ns $callback
393		722
…		…
405	# do nothing unless active	734	# do nothing unless active
406	$dispatcher->{_event_queue_h}	735	$dispatcher->{_event_queue_h}
407	or return;	736	or return;
408		737
409	# make the dispatcher handle any outstanding stuff	738	# make the dispatcher handle any outstanding stuff
		739	... not shown
410		740
411	# create an IO watcher for each and every socket	741	# create an I/O watcher for each and every socket
412	@snmp_watcher = (	742	@snmp_watcher = (
413	(map { EV::io $_, EV::READ, sub { } }	743	(map { EV::io $_, EV::READ, sub { } }
414	keys %{ $dispatcher->{_descriptors} }),	744	keys %{ $dispatcher->{_descriptors} }),
		745
		746	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		747	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		748	0, sub { },
415	);	749	);
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	};	750	};
421		751
422	The callbacks are irrelevant, the only purpose of those watchers is	752	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	753	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	754	one of those events occurs (socket readable, or timer timed out). The
425	clean up:	755	corresponding EV::check watcher will then clean up:
426		756
427	our $snmp_check = EV::check sub {	757	our $snmp_check = EV::check sub {
428	# destroy all watchers	758	# destroy all watchers
429	@snmp_watcher = ();	759	@snmp_watcher = ();
430		760
431	# make the dispatcher handle any new stuff	761	# make the dispatcher handle any new stuff
		762	... not shown
432	};	763	};
433		764
434	The callbacks of the created watchers will not be called as the watchers	765	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	766	are destroyed before this cna happen (remember EV::check gets called
436	first).	767	first).
437		768
438	The C<check_ns> variant doesn't start (activate) the newly created watcher.	769	The C<check_ns> variant doesn't start (activate) the newly created watcher.
439		770
440	=back	771	=back
441		772
		773
		774	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		775
		776	Fork watchers are called when a C<fork ()> was detected. The invocation
		777	is done before the event loop blocks next and before C<check> watchers
		778	are being called, and only in the child after the fork.
		779
		780	=over 4
		781
		782	=item $w = EV::fork $callback
		783
		784	=item $w = EV::fork_ns $callback
		785
		786	Call the callback before the event loop is resumed in the child process
		787	after a fork.
		788
		789	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		790
		791	=back
		792
		793
		794	=head1 PERL SIGNALS
		795
		796	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		797	with EV is as the same as any other C library: Perl-signals will only be
		798	handled when Perl runs, which means your signal handler might be invoked
		799	only the next time an event callback is invoked.
		800
		801	The solution is to use EV signal watchers (see C<EV::signal>), which will
		802	ensure proper operations with regards to other event watchers.
		803
		804	If you cannot do this for whatever reason, you can also force a watcher
		805	to be called on every event loop iteration by installing a C<EV::check>
		806	watcher:
		807
		808	my $async_check = EV::check sub { };
		809
		810	This ensures that perl shortly gets into control for a short time, and
		811	also ensures slower overall operation.
		812
442	=head1 THREADS	813	=head1 THREADS
443		814
444	Threads are not supported by this in any way. Perl pseudo-threads is evil	815	Threads are not supported by this module in any way. Perl pseudo-threads
445	stuff and must die.	816	is evil stuff and must die. As soon as Perl gains real threads I will work
		817	on thread support for it.
		818
		819	=head1 FORK
		820
		821	Most of the "improved" event delivering mechanisms of modern operating
		822	systems have quite a few problems with fork(2) (to put it bluntly: it is
		823	not supported and usually destructive). Libev makes it possible to work
		824	around this by having a function that recreates the kernel state after
		825	fork in the child.
		826
		827	On non-win32 platforms, this module requires the pthread_atfork
		828	functionality to do this automatically for you. This function is quite
		829	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		830	negligible, because everything the function currently does is set a flag
		831	that is checked only when the event loop gets used the next time, so when
		832	you do fork but not use EV, the overhead is minimal.
		833
		834	On win32, there is no notion of fork so all this doesn't apply, of course.
446		835
447	=cut	836	=cut
448		837
449	our $DIED = sub {	838	our $DIED = sub {
450	warn "EV: error in callback (ignoring): $@";	839	warn "EV: error in callback (ignoring): $@";
451	};	840	};
452		841
453	init;	842	default_loop
454		843	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
455	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
456		844
457	1;	845	1;
458		846
459	=head1 SEE ALSO	847	=head1 SEE ALSO
460		848
461	L<EV::DNS>, L<EV::AnyEvent>.	849	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		850	event loop), L<Coro::EV> (efficient coroutines with EV).
462		851
463	=head1 AUTHOR	852	=head1 AUTHOR
464		853
465	Marc Lehmann <schmorp@schmorp.de>	854	Marc Lehmann <schmorp@schmorp.de>
466	http://home.schmorp.de/	855	http://home.schmorp.de/

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing EV/EV.pm (file contents): Revision 1.22 by root, Fri Nov 2 11:02:22 2007 UTC vs. Revision 1.67 by root, Sun Dec 9 02:14:23 2007 UTC

Diff Legend

Comparing EV/EV.pm (file contents):
Revision 1.22 by root, Fri Nov 2 11:02:22 2007 UTC vs.
Revision 1.67 by root, Sun Dec 9 02:14:23 2007 UTC