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

Comparing EV/EV.pm (file contents):
Revision 1.20 by root, Thu Nov 1 17:17:32 2007 UTC vs.
Revision 1.71 by root, Mon Dec 17 07:24:12 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 = '1.86';
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.	456	In this mode $interval and $at are both being ignored. Instead, each
		457	time the periodic watcher gets scheduled, the reschedule callback
		458	($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
297		487
298	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.
299		489
300	=item $w->set ($at, $interval)	490	=item $w->set ($at, $interval, $reschedule_cb)
301		491
302	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
303	any time.	493	any time.
304		494
		495	=item $w->again
		496
		497	Simply stops and starts the watcher again.
		498
		499	=item $time = $w->at
		500
		501	Return the time that the watcher is expected to trigger next.
		502
		503	=back
		504
		505
		506	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		507
		508	=over 4
305		509
306	=item $w = EV::signal $signal, $callback	510	=item $w = EV::signal $signal, $callback
307		511
308	=item $w = EV::signal_ns $signal, $callback	512	=item $w = EV::signal_ns $signal, $callback
309		513
310	Call the callback when $signal is received (the signal can be specified	514	Call the callback when $signal is received (the signal can be specified by
311	by number or by name, just as with kill or %SIG).	515	number or by name, just as with C<kill> or C<%SIG>).
312		516
313	EV will grab the signal for the process (the kernel only allows one	517	EV will grab the signal for the process (the kernel only allows one
314	component to receive a signal at a time) when you start a signal watcher,	518	component to receive a signal at a time) when you start a signal watcher,
315	and removes it again when you stop it. Perl does the same when you	519	and removes it again when you stop it. Perl does the same when you
316	add/remove callbacks to %SIG, so watch out.	520	add/remove callbacks to C<%SIG>, so watch out.
317		521
318	You can have as many signal watchers per signal as you want.	522	You can have as many signal watchers per signal as you want.
319		523
320	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	524	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
321		525
322	=item $w->set ($signal)	526	=item $w->set ($signal)
323		527
324	Reconfigures the watcher, see the constructor above for details. Can be at	528	Reconfigures the watcher, see the constructor above for details. Can be
		529	called at any time.
		530
		531	=item $current_signum = $w->signal
		532
		533	=item $old_signum = $w->signal ($new_signal)
		534
		535	Returns the previously set signal (always as a number not name) and
		536	optionally set a new one.
		537
		538	=back
		539
		540
		541	=head3 CHILD WATCHERS - watch out for process status changes
		542
		543	=over 4
		544
		545	=item $w = EV::child $pid, $callback
		546
		547	=item $w = EV::child_ns $pid, $callback
		548
		549	Call the callback when a status change for pid C<$pid> (or any pid if
		550	C<$pid> is 0) has been received. More precisely: when the process receives
		551	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
		552	changed/zombie children and call the callback.
		553
		554	It is valid (and fully supported) to install a child watcher after a child
		555	has exited but before the event loop has started its next iteration (for
		556	example, first you C<fork>, then the new child process might exit, and
		557	only then do you install a child watcher in the parent for the new pid).
		558
		559	You can access both exit (or tracing) status and pid by using the
		560	C<rstatus> and C<rpid> methods on the watcher object.
		561
		562	You can have as many pid watchers per pid as you want, they will all be
		563	called.
		564
		565	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		566
		567	=item $w->set ($pid)
		568
		569	Reconfigures the watcher, see the constructor above for details. Can be called at
325	any time.	570	any time.
326		571
		572	=item $current_pid = $w->pid
327		573
328	=item $w = EV::child $pid, $callback	574	=item $old_pid = $w->pid ($new_pid)
329		575
330	=item $w = EV::child_ns $pid, $callback	576	Returns the previously set process id and optionally set a new one.
331		577
332	Call the callback when a status change for pid C<$pid> (or any pid	578	=item $exit_status = $w->rstatus
333	if C<$pid> is 0) has been received. More precisely: when the process
334	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all
335	changed/zombie children and call the callback.
336		579
337	Unlike all other callbacks, this callback will be called with an	580	Return the exit/wait status (as returned by waitpid, see the waitpid entry
338	additional third argument which is the exit status. See the C<waitpid>	581	in perlfunc).
339	function for details.
340		582
341	You can have as many pid watchers per pid as you want.	583	=item $pid = $w->rpid
342		584
		585	Return the pid of the awaited child (useful when you have installed a
		586	watcher for all pids).
		587
		588	=back
		589
		590
		591	=head3 STAT WATCHERS - did the file attributes just change?
		592
		593	=over 4
		594
		595	=item $w = EV::stat $path, $interval, $callback
		596
		597	=item $w = EV::stat_ns $path, $interval, $callback
		598
		599	Call the callback when a file status change has been detected on
		600	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		601	to "path does not exist" is a status change like any other.
		602
		603	The C<$interval> is a recommended polling interval for systems where
		604	OS-supported change notifications don't exist or are not supported. If
		605	you use C<0> then an unspecified default is used (which is highly
		606	recommended!), which is to be expected to be around five seconds usually.
		607
		608	This watcher type is not meant for massive numbers of stat watchers,
		609	as even with OS-supported change notifications, this can be
		610	resource-intensive.
		611
343	The C<child_ns> variant doesn't start (activate) the newly created watcher.	612	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
344		613
345	=item $w->set ($pid)	614	=item ... = $w->stat
346		615
		616	This call is very similar to the perl C<stat> built-in: It stats (using
		617	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		618	well as EV's idea of the current stat values) to the values found.
		619
		620	In scalar context, a boolean is return indicating success or failure of
		621	the stat. In list context, the same 13-value list as with stat is returned
		622	(except that the blksize and blocks fields are not reliable).
		623
		624	In the case of an error, errno is set to C<ENOENT> (regardless of the
		625	actual error value) and the C<nlink> value is forced to zero (if the stat
		626	was successful then nlink is guaranteed to be non-zero).
		627
		628	See also the next two entries for more info.
		629
		630	=item ... = $w->attr
		631
		632	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		633	the values most recently detected by EV. See the next entry for more info.
		634
		635	=item ... = $w->prev
		636
		637	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		638	the previous set of values, before the change.
		639
		640	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		641	to the values found I<before> a change was detected, while C<< $w->attr >>
		642	returns the values found leading to the change detection. The difference (if any)
		643	between C<prev> and C<attr> is what triggered the callback.
		644
		645	If you did something to the filesystem object and do not want to trigger
		646	yet another change, you can call C<stat> to update EV's idea of what the
		647	current attributes are.
		648
		649	=item $w->set ($path, $interval)
		650
347	Reconfigures the watcher, see the constructor above for details. Can be at	651	Reconfigures the watcher, see the constructor above for details. Can be
348	any time.	652	called at any time.
349		653
		654	=item $current_path = $w->path
		655
		656	=item $old_path = $w->path ($new_path)
		657
		658	Returns the previously set path and optionally set a new one.
		659
		660	=item $current_interval = $w->interval
		661
		662	=item $old_interval = $w->interval ($new_interval)
		663
		664	Returns the previously set interval and optionally set a new one. Can be
		665	used to query the actual interval used.
		666
		667	=back
		668
		669
		670	=head3 IDLE WATCHERS - when you've got nothing better to do...
		671
		672	=over 4
350		673
351	=item $w = EV::idle $callback	674	=item $w = EV::idle $callback
352		675
353	=item $w = EV::idle_ns $callback	676	=item $w = EV::idle_ns $callback
354		677
355	Call the callback when there are no pending io, timer/periodic, signal or	678	Call the callback when there are no other pending watchers of the same or
356	child events, i.e. when the process is idle.	679	higher priority (excluding check, prepare and other idle watchers of the
		680	same or lower priority, of course). They are called idle watchers because
		681	when the watcher is the highest priority pending event in the process, the
		682	process is considered to be idle at that priority.
		683
		684	If you want a watcher that is only ever called when I<no> other events are
		685	outstanding you have to set the priority to C<EV::MINPRI>.
357		686
358	The process will not block as long as any idle watchers are active, and	687	The process will not block as long as any idle watchers are active, and
359	they will be called repeatedly until stopped.	688	they will be called repeatedly until stopped.
360		689
		690	For example, if you have idle watchers at priority C<0> and C<1>, and
		691	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		692	and the I/O watcher will always run when ready. Only when the idle watcher
		693	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		694	pending with the C<0>-priority idle watcher be invoked.
		695
361	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	696	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
362		697
		698	=back
		699
		700
		701	=head3 PREPARE WATCHERS - customise your event loop!
		702
		703	=over 4
363		704
364	=item $w = EV::prepare $callback	705	=item $w = EV::prepare $callback
365		706
366	=item $w = EV::prepare_ns $callback	707	=item $w = EV::prepare_ns $callback
367		708
…		…
370		711
371	See the EV::check watcher, below, for explanations and an example.	712	See the EV::check watcher, below, for explanations and an example.
372		713
373	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	714	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
374		715
		716	=back
		717
		718
		719	=head3 CHECK WATCHERS - customise your event loop even more!
		720
		721	=over 4
375		722
376	=item $w = EV::check $callback	723	=item $w = EV::check $callback
377		724
378	=item $w = EV::check_ns $callback	725	=item $w = EV::check_ns $callback
379		726
…		…
391	# do nothing unless active	738	# do nothing unless active
392	$dispatcher->{_event_queue_h}	739	$dispatcher->{_event_queue_h}
393	or return;	740	or return;
394		741
395	# make the dispatcher handle any outstanding stuff	742	# make the dispatcher handle any outstanding stuff
		743	... not shown
396		744
397	# create an IO watcher for each and every socket	745	# create an I/O watcher for each and every socket
398	@snmp_watcher = (	746	@snmp_watcher = (
399	(map { EV::io $_, EV::READ, sub { } }	747	(map { EV::io $_, EV::READ, sub { } }
400	keys %{ $dispatcher->{_descriptors} }),	748	keys %{ $dispatcher->{_descriptors} }),
		749
		750	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		751	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		752	0, sub { },
401	);	753	);
402
403	# if there are any timeouts, also create a timer
404	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
405	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
406	};	754	};
407		755
408	The callbacks are irrelevant, the only purpose of those watchers is	756	The callbacks are irrelevant (and are not even being called), the
409	to wake up the process as soon as one of those events occurs (socket	757	only purpose of those watchers is to wake up the process as soon as
410	readable, or timer timed out). The corresponding EV::check watcher will then	758	one of those events occurs (socket readable, or timer timed out). The
411	clean up:	759	corresponding EV::check watcher will then clean up:
412		760
413	our $snmp_check = EV::check sub {	761	our $snmp_check = EV::check sub {
414	# destroy all watchers	762	# destroy all watchers
415	@snmp_watcher = ();	763	@snmp_watcher = ();
416		764
417	# make the dispatcher handle any new stuff	765	# make the dispatcher handle any new stuff
		766	... not shown
418	};	767	};
419		768
420	The callbacks of the created watchers will not be called as the watchers	769	The callbacks of the created watchers will not be called as the watchers
421	are destroyed before this cna happen (remember EV::check gets called	770	are destroyed before this cna happen (remember EV::check gets called
422	first).	771	first).
423		772
424	The C<check_ns> variant doesn't start (activate) the newly created watcher.	773	The C<check_ns> variant doesn't start (activate) the newly created watcher.
425		774
426	=back	775	=back
427		776
		777
		778	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		779
		780	Fork watchers are called when a C<fork ()> was detected. The invocation
		781	is done before the event loop blocks next and before C<check> watchers
		782	are being called, and only in the child after the fork.
		783
		784	=over 4
		785
		786	=item $w = EV::fork $callback
		787
		788	=item $w = EV::fork_ns $callback
		789
		790	Call the callback before the event loop is resumed in the child process
		791	after a fork.
		792
		793	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		794
		795	=back
		796
		797
		798	=head1 PERL SIGNALS
		799
		800	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		801	with EV is as the same as any other C library: Perl-signals will only be
		802	handled when Perl runs, which means your signal handler might be invoked
		803	only the next time an event callback is invoked.
		804
		805	The solution is to use EV signal watchers (see C<EV::signal>), which will
		806	ensure proper operations with regards to other event watchers.
		807
		808	If you cannot do this for whatever reason, you can also force a watcher
		809	to be called on every event loop iteration by installing a C<EV::check>
		810	watcher:
		811
		812	my $async_check = EV::check sub { };
		813
		814	This ensures that perl shortly gets into control for a short time, and
		815	also ensures slower overall operation.
		816
428	=head1 THREADS	817	=head1 THREADS
429		818
430	Threads are not supported by this in any way. Perl pseudo-threads is evil	819	Threads are not supported by this module in any way. Perl pseudo-threads
431	stuff and must die.	820	is evil stuff and must die. As soon as Perl gains real threads I will work
		821	on thread support for it.
		822
		823	=head1 FORK
		824
		825	Most of the "improved" event delivering mechanisms of modern operating
		826	systems have quite a few problems with fork(2) (to put it bluntly: it is
		827	not supported and usually destructive). Libev makes it possible to work
		828	around this by having a function that recreates the kernel state after
		829	fork in the child.
		830
		831	On non-win32 platforms, this module requires the pthread_atfork
		832	functionality to do this automatically for you. This function is quite
		833	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		834	negligible, because everything the function currently does is set a flag
		835	that is checked only when the event loop gets used the next time, so when
		836	you do fork but not use EV, the overhead is minimal.
		837
		838	On win32, there is no notion of fork so all this doesn't apply, of course.
432		839
433	=cut	840	=cut
434		841
435	our $DIED = sub {	842	our $DIED = sub {
436	warn "EV: error in callback (ignoring): $@";	843	warn "EV: error in callback (ignoring): $@";
437	};	844	};
438		845
439	init;	846	default_loop
440		847	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
441	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
442		848
443	1;	849	1;
444		850
445	=head1 SEE ALSO	851	=head1 SEE ALSO
446		852
447	L<EV::DNS>, L<EV::AnyEvent>.	853	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		854	event loop), L<Coro::EV> (efficient coroutines with EV).
448		855
449	=head1 AUTHOR	856	=head1 AUTHOR
450		857
451	Marc Lehmann <schmorp@schmorp.de>	858	Marc Lehmann <schmorp@schmorp.de>
452	http://home.schmorp.de/	859	http://home.schmorp.de/

Diff Legend

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

Comparing EV/EV.pm (file contents): Revision 1.20 by root, Thu Nov 1 17:17:32 2007 UTC vs. Revision 1.71 by root, Mon Dec 17 07:24:12 2007 UTC

Diff Legend

Comparing EV/EV.pm (file contents):
Revision 1.20 by root, Thu Nov 1 17:17:32 2007 UTC vs.
Revision 1.71 by root, Mon Dec 17 07:24:12 2007 UTC