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

Comparing EV/EV.pm (file contents):
Revision 1.23 by root, Fri Nov 2 20:21:33 2007 UTC vs.
Revision 1.83 by root, Mon Jan 28 12:24:05 2008 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	my $w = EV::signal 3, sub {	38	# CHILD/PID STATUS CHANGES
39	warn "sigquit received (this is GNU/Linux, right?)\n";	39
		40	my $w = EV::child 666, 0, sub {
		41	my ($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 = '3.0';
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";
		92
		93	=head1 EVENT LOOPS
		94
		95	EV supports multiple event loops: There is a single "default event loop"
		96	that can handle everything including signals and child watchers, and any
		97	number of "dynamic event loops" that can use different backends (with
		98	various limitations), but no child and signal watchers.
		99
		100	You do not have to do anything to create the default event loop: When
		101	the module is loaded a suitable backend is selected on the premise of
		102	selecting a working backend (which for example rules out kqueue on most
		103	BSDs). Modules should, unless they have "special needs" always use the
		104	default loop as this is fastest (perl-wise), best supported by other
		105	modules (e.g. AnyEvent or Coro) and most portable event loop.
		106
		107	For specific programs you can create additional event loops dynamically.
		108
		109	=over 4
		110
		111	=item $loop = new EV::loop [$flags]
		112
		113	Create a new event loop as per the specified flags. Please refer to the
		114	C<ev_loop_new ()> function description in the libev documentation
		115	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		116	for more info.
		117
		118	The loop will automatically be destroyed when it is no longer referenced
		119	by any watcher and the loop object goes out of scope.
		120
		121	Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
		122	is protected by this module.
		123
		124	=item $loop->loop_fork
		125
		126	Must be called after a fork in the child, before entering or continuing
		127	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		128	this fucntion automatically, at some performance loss (refer to the libev
		129	documentation).
		130
		131	=item $loop = EV::default_loop [$flags]
		132
		133	Return the default loop (which is a singleton object).
		134
		135	=back
		136
78		137
79	=head1 BASIC INTERFACE	138	=head1 BASIC INTERFACE
80		139
81	=over 4	140	=over 4
82		141
83	=item $EV::DIED	142	=item $EV::DIED
84		143
85	Must contain a reference to a function that is called when a callback	144	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	145	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	146	informative message and continues.
88		147
89	If this callback throws an exception it will be silently ignored.	148	If this callback throws an exception it will be silently ignored.
90		149
		150	=item $flags = EV::supported_backends
		151
		152	=item $flags = EV::recommended_backends
		153
		154	=item $flags = EV::embeddable_backends
		155
		156	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		157	instance of EV, the set of recommended backends (supposed to be good) for
		158	this platform and the set of embeddable backends (see EMBED WATCHERS).
		159
		160	=item EV::sleep $seconds
		161
		162	Block the process for the given number of (fractional) seconds.
		163
91	=item $time = EV::time	164	=item $time = EV::time
92		165
93	Returns the current time in (fractional) seconds since the epoch.	166	Returns the current time in (fractional) seconds since the epoch.
94		167
95	=item $time = EV::now	168	=item $time = EV::now
		169
		170	=item $time = $loop->now
96		171
97	Returns the time the last event loop iteration has been started. This	172	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	173	is the time that (relative) timers are based on, and refering to it is
99	usually faster then calling EV::time.	174	usually faster then calling EV::time.
100		175
101	=item $method = EV::ev_method	176	=item $backend = EV::backend
		177
		178	=item $backend = $loop->backend
102		179
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	180	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
104	or EV::METHOD_EPOLL).	181	or EV::METHOD_EPOLL).
105		182
106	=item EV::loop [$flags]	183	=item EV::loop [$flags]
107		184
		185	=item $loop->loop ([$flags])
		186
108	Begin checking for events and calling callbacks. It returns when a	187	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	188	callback calls EV::unloop.
110		189
111	The $flags argument can be one of the following:	190	The $flags argument can be one of the following:
112		191
113	0 as above	192	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	193	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	194	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		195
117	=item EV::loop_done [$how]	196	=item EV::unloop [$how]
118		197
		198	=item $loop->unloop ([$how])
		199
119	When called with no arguments or an argument of 1, makes the innermost	200	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	201	innermost call to EV::loop return.
121		202
122	When called with an agrument of 2, all calls to EV::loop will return as	203	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	204	fast as possible.
124		205
125	=back	206	=item $count = EV::loop_count
126		207
127	=head2 WATCHER	208	=item $count = $loop->loop_count
		209
		210	Return the number of times the event loop has polled for new
		211	events. Sometiems useful as a generation counter.
		212
		213	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		214
		215	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		216
		217	This function rolls together an I/O and a timer watcher for a single
		218	one-shot event without the need for managing a watcher object.
		219
		220	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		221	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		222	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		223	you do not want to wait for some I/O event, specify C<undef> for
		224	C<$fh_or_undef> and C<0> for C<$events>).
		225
		226	If timeout is C<undef> or negative, then there will be no
		227	timeout. Otherwise a EV::timer with this value will be started.
		228
		229	When an error occurs or either the timeout or I/O watcher triggers, then
		230	the callback will be called with the received event set (in general
		231	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		232	C<EV::WRITE> and C<EV::TIMEOUT>).
		233
		234	EV::once doesn't return anything: the watchers stay active till either
		235	of them triggers, then they will be stopped and freed, and the callback
		236	invoked.
		237
		238	=item EV::feed_fd_event ($fd, $revents)
		239
		240	=item $loop->feed_fd_event ($fd, $revents)
		241
		242	Feed an event on a file descriptor into EV. EV will react to this call as
		243	if the readyness notifications specified by C<$revents> (a combination of
		244	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		245
		246	=item EV::feed_signal_event ($signal)
		247
		248	Feed a signal event into EV. EV will react to this call as if the signal
		249	specified by C<$signal> had occured.
		250
		251	=item EV::set_io_collect_interval $time
		252
		253	=item $loop->set_io_collect_interval ($time)
		254
		255	=item EV::set_timeout_collect_interval $time
		256
		257	=item $loop->set_timeout_collect_interval ($time)
		258
		259	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		260	wait interval for timer events. See the libev documentation at
		261	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		262	a more detailed discussion.
		263
		264	=back
		265
		266
		267	=head1 WATCHER OBJECTS
128		268
129	A watcher is an object that gets created to record your interest in some	269	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	270	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	271	would create an EV::io watcher for that:
132		272
133	my $watcher = EV::io *STDIN, EV::READ, sub {	273	my $watcher = EV::io *STDIN, EV::READ, sub {
134	my ($watcher, $revents) = @_;	274	my ($watcher, $revents) = @_;
135	warn "yeah, STDIN should not be readable without blocking!\n"	275	warn "yeah, STDIN should now be readable without blocking!\n"
136	};	276	};
137		277
138	All watchers can be active (waiting for events) or inactive (paused). Only	278	All watchers can be active (waiting for events) or inactive (paused). Only
139	active watchers will have their callbacks invoked. All callbacks will be	279	active watchers will have their callbacks invoked. All callbacks will be
140	called with at least two arguments: the watcher and a bitmask of received	280	called with at least two arguments: the watcher and a bitmask of received
141	events.	281	events.
142		282
143	Each watcher type has its associated bit in revents, so you can use the	283	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	284	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,	285	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	286	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	287	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	288	uses EV::TIMEOUT).
149		289
150	In the rare case where one wants to create a watcher but not start it at	290	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	291	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
157		297
158	Also, all methods changing some aspect of a watcher (->set, ->priority,	298	Also, all methods changing some aspect of a watcher (->set, ->priority,
159	->fh and so on) automatically stop and start it again if it is active,	299	->fh and so on) automatically stop and start it again if it is active,
160	which means pending events get lost.	300	which means pending events get lost.
161		301
162	=head2 WATCHER TYPES	302	=head2 COMMON WATCHER METHODS
163		303
164	Now lets move to the existing watcher types and asociated methods.	304	This section lists methods common to all watchers.
165
166	The following methods are available for all watchers. Then followes a
167	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
168	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
169	any type-specific methods (if any).
170		305
171	=over 4	306	=over 4
172		307
173	=item $w->start	308	=item $w->start
174		309
…		…
178		313
179	=item $w->stop	314	=item $w->stop
180		315
181	Stop a watcher if it is active. Also clear any pending events (events that	316	Stop a watcher if it is active. Also clear any pending events (events that
182	have been received but that didn't yet result in a callback invocation),	317	have been received but that didn't yet result in a callback invocation),
183	regardless of wether the watcher was active or not.	318	regardless of whether the watcher was active or not.
184		319
185	=item $bool = $w->is_active	320	=item $bool = $w->is_active
186		321
187	Returns true if the watcher is active, false otherwise.	322	Returns true if the watcher is active, false otherwise.
		323
		324	=item $current_data = $w->data
		325
		326	=item $old_data = $w->data ($new_data)
		327
		328	Queries a freely usable data scalar on the watcher and optionally changes
		329	it. This is a way to associate custom data with a watcher:
		330
		331	my $w = EV::timer 60, 0, sub {
		332	warn $_[0]->data;
		333	};
		334	$w->data ("print me!");
188		335
189	=item $current_cb = $w->cb	336	=item $current_cb = $w->cb
190		337
191	=item $old_cb = $w->cb ($new_cb)	338	=item $old_cb = $w->cb ($new_cb)
192		339
…		…
197		344
198	=item $old_priority = $w->priority ($new_priority)	345	=item $old_priority = $w->priority ($new_priority)
199		346
200	Queries the priority on the watcher and optionally changes it. Pending	347	Queries the priority on the watcher and optionally changes it. Pending
201	watchers with higher priority will be invoked first. The valid range of	348	watchers with higher priority will be invoked first. The valid range of
202	priorities lies between EV::MAXPRI (default 3) and EV::MINPRI (default	349	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
203	-3). If the priority is outside this range it will automatically be	350	-2). If the priority is outside this range it will automatically be
204	normalised to the nearest valid priority.	351	normalised to the nearest valid priority.
205		352
206	The default priority of any newly-created weatcher is 0.	353	The default priority of any newly-created watcher is 0.
207		354
		355	Note that the priority semantics have not yet been fleshed out and are
		356	subject to almost certain change.
		357
208	=item $w->trigger ($revents)	358	=item $w->invoke ($revents)
209		359
210	Call the callback now with the given event mask.	360	Call the callback now with the given event mask.
211		361
		362	=item $w->feed_event ($revents)
		363
		364	Feed some events on this watcher into EV. EV will react to this call as if
		365	the watcher had received the given C<$revents> mask.
		366
		367	=item $revents = $w->clear_pending
		368
		369	If the watcher is pending, this function clears its pending status and
		370	returns its C<$revents> bitset (as if its callback was invoked). If the
		371	watcher isn't pending it does nothing and returns C<0>.
		372
		373	=item $previous_state = $w->keepalive ($bool)
		374
		375	Normally, C<EV::loop> will return when there are no active watchers
		376	(which is a "deadlock" because no progress can be made anymore). This is
		377	convinient because it allows you to start your watchers (and your jobs),
		378	call C<EV::loop> once and when it returns you know that all your jobs are
		379	finished (or they forgot to register some watchers for their task :).
		380
		381	Sometimes, however, this gets in your way, for example when the module
		382	that calls C<EV::loop> (usually the main program) is not the same module
		383	as a long-living watcher (for example a DNS client module written by
		384	somebody else even). Then you might want any outstanding requests to be
		385	handled, but you would not want to keep C<EV::loop> from returning just
		386	because you happen to have this long-running UDP port watcher.
		387
		388	In this case you can clear the keepalive status, which means that even
		389	though your watcher is active, it won't keep C<EV::loop> from returning.
		390
		391	The initial value for keepalive is true (enabled), and you cna change it
		392	any time.
		393
		394	Example: Register an I/O watcher for some UDP socket but do not keep the
		395	event loop from running just because of that watcher.
		396
		397	my $udp_socket = ...
		398	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		399	$1000udp_watcher->keepalive (0);
		400
		401	=item $loop = $w->loop
		402
		403	Return the loop that this watcher is attached to.
		404
		405	=back
		406
		407
		408	=head1 WATCHER TYPES
		409
		410	Each of the following subsections describes a single watcher type.
		411
		412	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		413
		414	=over 4
212		415
213	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	416	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
214		417
215	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	418	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
216		419
		420	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		421
		422	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		423
217	As long as the returned watcher object is alive, call the C<$callback>	424	As long as the returned watcher object is alive, call the C<$callback>
218	when the events specified in C<$eventmask>.	425	when at least one of events specified in C<$eventmask> occurs.
219		426
220	The $eventmask can be one or more of these constants ORed together:	427	The $eventmask can be one or more of these constants ORed together:
221		428
222	EV::READ wait until read() wouldn't block anymore	429	EV::READ wait until read() wouldn't block anymore
223	EV::WRITE wait until write() wouldn't block anymore	430	EV::WRITE wait until write() wouldn't block anymore
…		…
239		446
240	=item $old_eventmask = $w->events ($new_eventmask)	447	=item $old_eventmask = $w->events ($new_eventmask)
241		448
242	Returns the previously set event mask and optionally set a new one.	449	Returns the previously set event mask and optionally set a new one.
243		450
		451	=back
		452
		453
		454	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		455
		456	=over 4
244		457
245	=item $w = EV::timer $after, $repeat, $callback	458	=item $w = EV::timer $after, $repeat, $callback
246		459
247	=item $w = EV::timer_ns $after, $repeat, $callback	460	=item $w = EV::timer_ns $after, $repeat, $callback
248		461
249	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	462	=item $w = $loop->timer ($after, $repeat, $callback)
250	the timer will be restarted (with the $repeat value as $after) after the	463
251	callback returns.	464	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		465
		466	Calls the callback after C<$after> seconds (which may be fractional). If
		467	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		468	value as $after) after the callback returns.
252		469
253	This means that the callback would be called roughly after C<$after>	470	This means that the callback would be called roughly after C<$after>
254	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	471	seconds, and then every C<$repeat> seconds. The timer does his best not
255	callback processing is not taken into account, so the timer will slowly	472	to drift, but it will not invoke the timer more often then once per event
256	drift. If that isn't acceptable, look at EV::periodic.	473	loop iteration, and might drift in other cases. If that isn't acceptable,
		474	look at EV::periodic, which can provide long-term stable timers.
257		475
258	The timer is based on a monotonic clock, that is if somebody is sitting	476	The timer is based on a monotonic clock, that is, if somebody is sitting
259	in front of the machine while the timer is running and changes the system	477	in front of the machine while the timer is running and changes the system
260	clock, the timer will nevertheless run (roughly) the same time.	478	clock, the timer will nevertheless run (roughly) the same time.
261		479
262	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	480	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
263		481
264	=item $w->set ($after, $repeat)	482	=item $w->set ($after, $repeat)
265		483
266	Reconfigures the watcher, see the constructor above for details. Can be at	484	Reconfigures the watcher, see the constructor above for details. Can be called at
267	any time.	485	any time.
268		486
269	=item $w->again	487	=item $w->again
270		488
271	Similar to the C<start> method, but has special semantics for repeating timers:	489	Similar to the C<start> method, but has special semantics for repeating timers:
		490
		491	If the timer is active and non-repeating, it will be stopped.
272		492
273	If the timer is active and repeating, reset the timeout to occur	493	If the timer is active and repeating, reset the timeout to occur
274	C<$repeat> seconds after now.	494	C<$repeat> seconds after now.
275		495
276	If the timer is active and non-repeating, it will be stopped.
277
278	If the timer is in active and repeating, start it.	496	If the timer is inactive and repeating, start it using the repeat value.
279		497
280	Otherwise do nothing.	498	Otherwise do nothing.
281		499
282	This behaviour is useful when you have a timeout for some IO	500	This behaviour is useful when you have a timeout for some IO
283	operation. You create a timer object with the same value for C<$after> and	501	operation. You create a timer object with the same value for C<$after> and
284	C<$repeat>, and then, in the read/write watcher, run the C<again> method	502	C<$repeat>, and then, in the read/write watcher, run the C<again> method
285	on the timeout.	503	on the timeout.
286		504
		505	=back
287		506
		507
		508	=head3 PERIODIC WATCHERS - to cron or not to cron?
		509
		510	=over 4
		511
288	=item $w = EV::periodic $at, $interval, $callback	512	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
289		513
290	=item $w = EV::periodic_ns $at, $interval, $callback	514	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
291		515
292	Similar to EV::timer, but the time is given as an absolute point in time	516	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
293	(C<$at>), plus an optional C<$interval>.
294		517
295	If the C<$interval> is zero, then the callback will be called at the time	518	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
296	C<$at> if that is in the future, or as soon as possible if it is in the
297	past. It will not automatically repeat.
298		519
299	If the C<$interval> is nonzero, then the watcher will always be scheduled	520	Similar to EV::timer, but is not based on relative timeouts but on
300	to time out at the next C<$at + N * $interval> time.	521	absolute times. Apart from creating "simple" timers that trigger "at" the
		522	specified time, it can also be used for non-drifting absolute timers and
		523	more complex, cron-like, setups that are not adversely affected by time
		524	jumps (i.e. when the system clock is changed by explicit date -s or other
		525	means such as ntpd). It is also the most complex watcher type in EV.
301		526
302	This can be used to schedule a callback to run at very regular intervals,	527	It has three distinct "modes":
303	as long as the processing time is less then the interval (otherwise	528
304	obviously events will be skipped).	529	=over 4
		530
		531	=item * absolute timer ($interval = $reschedule_cb = 0)
		532
		533	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		534	will not adjust when a time jump occurs, that is, if it is to be run
		535	at January 1st 2011 then it will run when the system time reaches or
		536	surpasses this time.
		537
		538	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		539
		540	In this mode the watcher will always be scheduled to time out at the
		541	next C<$at + N * $interval> time (for some integer N) and then repeat,
		542	regardless of any time jumps.
		543
		544	This can be used to create timers that do not drift with respect to system
		545	time:
		546
		547	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		548
		549	That doesn't mean there will always be 3600 seconds in between triggers,
		550	but only that the the clalback will be called when the system time shows a
		551	full hour (UTC).
305		552
306	Another way to think about it (for the mathematically inclined) is that	553	Another way to think about it (for the mathematically inclined) is that
307	EV::periodic will try to run the callback at the next possible time where	554	EV::periodic will try to run the callback in this mode at the next
308	C<$time = $at (mod $interval)>, regardless of any time jumps.	555	possible time where C<$time = $at (mod $interval)>, regardless of any time
		556	jumps.
309		557
310	This periodic timer is based on "wallclock time", that is, if the clock	558	=item * manual reschedule mode ($reschedule_cb = coderef)
311	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	559
312	the specified time. This means it will never drift (it might jitter, but	560	In this mode $interval and $at are both being ignored. Instead, each
313	it will not drift).	561	time the periodic watcher gets scheduled, the reschedule callback
		562	($reschedule_cb) will be called with the watcher as first, and the current
		563	time as second argument.
		564
		565	I<This callback MUST NOT stop or destroy this or any other periodic
		566	watcher, ever>. If you need to stop it, return 1e30 and stop it
		567	afterwards.
		568
		569	It must return the next time to trigger, based on the passed time value
		570	(that is, the lowest time value larger than to the second argument). It
		571	will usually be called just before the callback will be triggered, but
		572	might be called at other times, too.
		573
		574	This can be used to create very complex timers, such as a timer that
		575	triggers on each midnight, local time (actually 24 hours after the last
		576	midnight, to keep the example simple. If you know a way to do it correctly
		577	in about the same space (without requiring elaborate modules), drop me a
		578	note :):
		579
		580	my $daily = EV::periodic 0, 0, sub {
		581	my ($w, $now) = @_;
		582
		583	use Time::Local ();
		584	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		585	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		586	}, sub {
		587	print "it's midnight or likely shortly after, now\n";
		588	};
		589
		590	=back
314		591
315	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	592	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
316		593
317	=item $w->set ($at, $interval)	594	=item $w->set ($at, $interval, $reschedule_cb)
318		595
319	Reconfigures the watcher, see the constructor above for details. Can be at	596	Reconfigures the watcher, see the constructor above for details. Can be called at
320	any time.	597	any time.
321		598
		599	=item $w->again
		600
		601	Simply stops and starts the watcher again.
		602
		603	=item $time = $w->at
		604
		605	Return the time that the watcher is expected to trigger next.
		606
		607	=back
		608
		609
		610	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		611
		612	=over 4
322		613
323	=item $w = EV::signal $signal, $callback	614	=item $w = EV::signal $signal, $callback
324		615
325	=item $w = EV::signal_ns $signal, $callback	616	=item $w = EV::signal_ns $signal, $callback
326		617
327	Call the callback when $signal is received (the signal can be specified	618	Call the callback when $signal is received (the signal can be specified by
328	by number or by name, just as with kill or %SIG).	619	number or by name, just as with C<kill> or C<%SIG>).
329		620
330	EV will grab the signal for the process (the kernel only allows one	621	EV will grab the signal for the process (the kernel only allows one
331	component to receive a signal at a time) when you start a signal watcher,	622	component to receive a signal at a time) when you start a signal watcher,
332	and removes it again when you stop it. Perl does the same when you	623	and removes it again when you stop it. Perl does the same when you
333	add/remove callbacks to %SIG, so watch out.	624	add/remove callbacks to C<%SIG>, so watch out.
334		625
335	You can have as many signal watchers per signal as you want.	626	You can have as many signal watchers per signal as you want.
336		627
337	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	628	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
338		629
339	=item $w->set ($signal)	630	=item $w->set ($signal)
340		631
341	Reconfigures the watcher, see the constructor above for details. Can be at	632	Reconfigures the watcher, see the constructor above for details. Can be
342	any time.	633	called at any time.
343		634
344	=item $current_signum = $w->signal	635	=item $current_signum = $w->signal
345		636
346	=item $old_signum = $w->signal ($new_signal)	637	=item $old_signum = $w->signal ($new_signal)
347		638
348	Returns the previously set signal (always as a number not name) and	639	Returns the previously set signal (always as a number not name) and
349	optionally set a new one.	640	optionally set a new one.
350		641
		642	=back
351		643
		644
		645	=head3 CHILD WATCHERS - watch out for process status changes
		646
		647	=over 4
		648
352	=item $w = EV::child $pid, $callback	649	=item $w = EV::child $pid, $trace, $callback
353		650
354	=item $w = EV::child_ns $pid, $callback	651	=item $w = EV::child_ns $pid, $trace, $callback
		652
		653	=item $w = $loop->child ($pid, $trace, $callback)
		654
		655	=item $w = $loop->child_ns ($pid, $trace, $callback)
355		656
356	Call the callback when a status change for pid C<$pid> (or any pid	657	Call the callback when a status change for pid C<$pid> (or any pid
357	if C<$pid> is 0) has been received. More precisely: when the process	658	if C<$pid> is 0) has been received (a status change happens when the
		659	process terminates or is killed, or, when trace is true, additionally when
		660	it is stopped or continued). More precisely: when the process receives
358	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	661	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
359	changed/zombie children and call the callback.	662	changed/zombie children and call the callback.
360		663
361	Unlike all other callbacks, this callback will be called with an	664	It is valid (and fully supported) to install a child watcher after a child
362	additional third argument which is the exit status. See the C<waitpid>	665	has exited but before the event loop has started its next iteration (for
363	function for details.	666	example, first you C<fork>, then the new child process might exit, and
		667	only then do you install a child watcher in the parent for the new pid).
364		668
		669	You can access both exit (or tracing) status and pid by using the
		670	C<rstatus> and C<rpid> methods on the watcher object.
		671
365	You can have as many pid watchers per pid as you want.	672	You can have as many pid watchers per pid as you want, they will all be
		673	called.
366		674
367	The C<child_ns> variant doesn't start (activate) the newly created watcher.	675	The C<child_ns> variant doesn't start (activate) the newly created watcher.
368		676
369	=item $w->set ($pid)	677	=item $w->set ($pid, $trace)
370		678
371	Reconfigures the watcher, see the constructor above for details. Can be at	679	Reconfigures the watcher, see the constructor above for details. Can be called at
372	any time.	680	any time.
373		681
374	=item $current_pid = $w->pid	682	=item $current_pid = $w->pid
375		683
376	=item $old_pid = $w->pid ($new_pid)
377
378	Returns the previously set process id and optionally set a new one.	684	Returns the previously set process id and optionally set a new one.
379		685
		686	=item $exit_status = $w->rstatus
		687
		688	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		689	in perlfunc).
		690
		691	=item $pid = $w->rpid
		692
		693	Return the pid of the awaited child (useful when you have installed a
		694	watcher for all pids).
		695
		696	=back
		697
		698
		699	=head3 STAT WATCHERS - did the file attributes just change?
		700
		701	=over 4
		702
		703	=item $w = EV::stat $path, $interval, $callback
		704
		705	=item $w = EV::stat_ns $path, $interval, $callback
		706
		707	=item $w = $loop->stat ($path, $interval, $callback)
		708
		709	=item $w = $loop->stat_ns ($path, $interval, $callback)
		710
		711	Call the callback when a file status change has been detected on
		712	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		713	to "path does not exist" is a status change like any other.
		714
		715	The C<$interval> is a recommended polling interval for systems where
		716	OS-supported change notifications don't exist or are not supported. If
		717	you use C<0> then an unspecified default is used (which is highly
		718	recommended!), which is to be expected to be around five seconds usually.
		719
		720	This watcher type is not meant for massive numbers of stat watchers,
		721	as even with OS-supported change notifications, this can be
		722	resource-intensive.
		723
		724	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		725
		726	=item ... = $w->stat
		727
		728	This call is very similar to the perl C<stat> built-in: It stats (using
		729	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		730	well as EV's idea of the current stat values) to the values found.
		731
		732	In scalar context, a boolean is return indicating success or failure of
		733	the stat. In list context, the same 13-value list as with stat is returned
		734	(except that the blksize and blocks fields are not reliable).
		735
		736	In the case of an error, errno is set to C<ENOENT> (regardless of the
		737	actual error value) and the C<nlink> value is forced to zero (if the stat
		738	was successful then nlink is guaranteed to be non-zero).
		739
		740	See also the next two entries for more info.
		741
		742	=item ... = $w->attr
		743
		744	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		745	the values most recently detected by EV. See the next entry for more info.
		746
		747	=item ... = $w->prev
		748
		749	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		750	the previous set of values, before the change.
		751
		752	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		753	to the values found I<before> a change was detected, while C<< $w->attr >>
		754	returns the values found leading to the change detection. The difference (if any)
		755	between C<prev> and C<attr> is what triggered the callback.
		756
		757	If you did something to the filesystem object and do not want to trigger
		758	yet another change, you can call C<stat> to update EV's idea of what the
		759	current attributes are.
		760
		761	=item $w->set ($path, $interval)
		762
		763	Reconfigures the watcher, see the constructor above for details. Can be
		764	called at any time.
		765
		766	=item $current_path = $w->path
		767
		768	=item $old_path = $w->path ($new_path)
		769
		770	Returns the previously set path and optionally set a new one.
		771
		772	=item $current_interval = $w->interval
		773
		774	=item $old_interval = $w->interval ($new_interval)
		775
		776	Returns the previously set interval and optionally set a new one. Can be
		777	used to query the actual interval used.
		778
		779	=back
		780
		781
		782	=head3 IDLE WATCHERS - when you've got nothing better to do...
		783
		784	=over 4
380		785
381	=item $w = EV::idle $callback	786	=item $w = EV::idle $callback
382		787
383	=item $w = EV::idle_ns $callback	788	=item $w = EV::idle_ns $callback
384		789
385	Call the callback when there are no pending io, timer/periodic, signal or	790	=item $w = $loop->idle ($callback)
386	child events, i.e. when the process is idle.	791
		792	=item $w = $loop->idle_ns ($callback)
		793
		794	Call the callback when there are no other pending watchers of the same or
		795	higher priority (excluding check, prepare and other idle watchers of the
		796	same or lower priority, of course). They are called idle watchers because
		797	when the watcher is the highest priority pending event in the process, the
		798	process is considered to be idle at that priority.
		799
		800	If you want a watcher that is only ever called when I<no> other events are
		801	outstanding you have to set the priority to C<EV::MINPRI>.
387		802
388	The process will not block as long as any idle watchers are active, and	803	The process will not block as long as any idle watchers are active, and
389	they will be called repeatedly until stopped.	804	they will be called repeatedly until stopped.
390		805
		806	For example, if you have idle watchers at priority C<0> and C<1>, and
		807	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		808	and the I/O watcher will always run when ready. Only when the idle watcher
		809	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		810	pending with the C<0>-priority idle watcher be invoked.
		811
391	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	812	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
392		813
		814	=back
		815
		816
		817	=head3 PREPARE WATCHERS - customise your event loop!
		818
		819	=over 4
393		820
394	=item $w = EV::prepare $callback	821	=item $w = EV::prepare $callback
395		822
396	=item $w = EV::prepare_ns $callback	823	=item $w = EV::prepare_ns $callback
		824
		825	=item $w = $loop->prepare ($callback)
		826
		827	=item $w = $loop->prepare_ns ($callback)
397		828
398	Call the callback just before the process would block. You can still	829	Call the callback just before the process would block. You can still
399	create/modify any watchers at this point.	830	create/modify any watchers at this point.
400		831
401	See the EV::check watcher, below, for explanations and an example.	832	See the EV::check watcher, below, for explanations and an example.
402		833
403	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	834	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
404		835
		836	=back
		837
		838
		839	=head3 CHECK WATCHERS - customise your event loop even more!
		840
		841	=over 4
405		842
406	=item $w = EV::check $callback	843	=item $w = EV::check $callback
407		844
408	=item $w = EV::check_ns $callback	845	=item $w = EV::check_ns $callback
		846
		847	=item $w = $loop->check ($callback)
		848
		849	=item $w = $loop->check_ns ($callback)
409		850
410	Call the callback just after the process wakes up again (after it has	851	Call the callback just after the process wakes up again (after it has
411	gathered events), but before any other callbacks have been invoked.	852	gathered events), but before any other callbacks have been invoked.
412		853
413	This is used to integrate other event-based software into the EV	854	This is used to integrate other event-based software into the EV
…		…
421	# do nothing unless active	862	# do nothing unless active
422	$dispatcher->{_event_queue_h}	863	$dispatcher->{_event_queue_h}
423	or return;	864	or return;
424		865
425	# make the dispatcher handle any outstanding stuff	866	# make the dispatcher handle any outstanding stuff
		867	... not shown
426		868
427	# create an IO watcher for each and every socket	869	# create an I/O watcher for each and every socket
428	@snmp_watcher = (	870	@snmp_watcher = (
429	(map { EV::io $_, EV::READ, sub { } }	871	(map { EV::io $_, EV::READ, sub { } }
430	keys %{ $dispatcher->{_descriptors} }),	872	keys %{ $dispatcher->{_descriptors} }),
		873
		874	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		875	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		876	0, sub { },
431	);	877	);
432
433	# if there are any timeouts, also create a timer
434	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
435	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
436	};	878	};
437		879
438	The callbacks are irrelevant, the only purpose of those watchers is	880	The callbacks are irrelevant (and are not even being called), the
439	to wake up the process as soon as one of those events occurs (socket	881	only purpose of those watchers is to wake up the process as soon as
440	readable, or timer timed out). The corresponding EV::check watcher will then	882	one of those events occurs (socket readable, or timer timed out). The
441	clean up:	883	corresponding EV::check watcher will then clean up:
442		884
443	our $snmp_check = EV::check sub {	885	our $snmp_check = EV::check sub {
444	# destroy all watchers	886	# destroy all watchers
445	@snmp_watcher = ();	887	@snmp_watcher = ();
446		888
447	# make the dispatcher handle any new stuff	889	# make the dispatcher handle any new stuff
		890	... not shown
448	};	891	};
449		892
450	The callbacks of the created watchers will not be called as the watchers	893	The callbacks of the created watchers will not be called as the watchers
451	are destroyed before this cna happen (remember EV::check gets called	894	are destroyed before this cna happen (remember EV::check gets called
452	first).	895	first).
453		896
454	The C<check_ns> variant doesn't start (activate) the newly created watcher.	897	The C<check_ns> variant doesn't start (activate) the newly created watcher.
455		898
456	=back	899	=back
457		900
		901
		902	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		903
		904	Fork watchers are called when a C<fork ()> was detected. The invocation
		905	is done before the event loop blocks next and before C<check> watchers
		906	are being called, and only in the child after the fork.
		907
		908	=over 4
		909
		910	=item $w = EV::fork $callback
		911
		912	=item $w = EV::fork_ns $callback
		913
		914	=item $w = $loop->fork ($callback)
		915
		916	=item $w = $loop->fork_ns ($callback)
		917
		918	Call the callback before the event loop is resumed in the child process
		919	after a fork.
		920
		921	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		922
		923	=back
		924
		925
		926	=head3 EMBED WATCHERS - when one backend isn't enough...
		927
		928	This is a rather advanced watcher type that lets you embed one event loop
		929	into another (currently only IO events are supported in the embedded
		930	loop, other types of watchers might be handled in a delayed or incorrect
		931	fashion and must not be used).
		932
		933	See the libev documentation at
		934	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		935	for more details.
		936
		937	In short, this watcher is most useful on BSD systems without working
		938	kqueue to still be able to handle a large number of sockets:
		939
		940	my $socket_loop;
		941
		942	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		943	if (
		944	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		945	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		946	) {
		947	# use kqueue for sockets
		948	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		949	}
		950
		951	# use the default loop otherwise
		952	$socket_loop \|\|= EV::default_loop;
		953
		954	=over 4
		955
		956	=item $w = EV::embed $otherloop, $callback
		957
		958	=item $w = EV::embed_ns $otherloop, $callback
		959
		960	=item $w = $loop->embed ($otherloop, $callback)
		961
		962	=item $w = $loop->embed_ns ($otherloop, $callback)
		963
		964	Call the callback when the embedded event loop (C<$otherloop>) has any
		965	I/O activity. The C<$callback> should alwas be specified as C<undef> in
		966	this version of EV, which means the embedded event loop will be managed
		967	automatically.
		968
		969	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		970
		971	=back
		972
		973
		974	=head1 PERL SIGNALS
		975
		976	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		977	with EV is as the same as any other C library: Perl-signals will only be
		978	handled when Perl runs, which means your signal handler might be invoked
		979	only the next time an event callback is invoked.
		980
		981	The solution is to use EV signal watchers (see C<EV::signal>), which will
		982	ensure proper operations with regards to other event watchers.
		983
		984	If you cannot do this for whatever reason, you can also force a watcher
		985	to be called on every event loop iteration by installing a C<EV::check>
		986	watcher:
		987
		988	my $async_check = EV::check sub { };
		989
		990	This ensures that perl gets into control for a short time to handle any
		991	pending signals, and also ensures (slightly) slower overall operation.
		992
458	=head1 THREADS	993	=head1 THREADS
459		994
460	Threads are not supported by this in any way. Perl pseudo-threads is evil	995	Threads are not supported by this module in any way. Perl pseudo-threads
461	stuff and must die.	996	is evil stuff and must die. As soon as Perl gains real threads I will work
		997	on thread support for it.
		998
		999	=head1 FORK
		1000
		1001	Most of the "improved" event delivering mechanisms of modern operating
		1002	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1003	not supported and usually destructive). Libev makes it possible to work
		1004	around this by having a function that recreates the kernel state after
		1005	fork in the child.
		1006
		1007	On non-win32 platforms, this module requires the pthread_atfork
		1008	functionality to do this automatically for you. This function is quite
		1009	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1010	negligible, because everything the function currently does is set a flag
		1011	that is checked only when the event loop gets used the next time, so when
		1012	you do fork but not use EV, the overhead is minimal.
		1013
		1014	On win32, there is no notion of fork so all this doesn't apply, of course.
462		1015
463	=cut	1016	=cut
464		1017
465	our $DIED = sub {	1018	our $DIED = sub {
466	warn "EV: error in callback (ignoring): $@";	1019	warn "EV: error in callback (ignoring): $@";
467	};	1020	};
468		1021
469	init;	1022	default_loop
470		1023	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
471	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
472		1024
473	1;	1025	1;
474		1026
475	=head1 SEE ALSO	1027	=head1 SEE ALSO
476		1028
477	L<EV::DNS>, L<EV::AnyEvent>.	1029	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1030	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1031	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP).
478		1032
479	=head1 AUTHOR	1033	=head1 AUTHOR
480		1034
481	Marc Lehmann <schmorp@schmorp.de>	1035	Marc Lehmann <schmorp@schmorp.de>
482	http://home.schmorp.de/	1036	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.23 by root, Fri Nov 2 20:21:33 2007 UTC vs. Revision 1.83 by root, Mon Jan 28 12:24:05 2008 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.23 by root, Fri Nov 2 20:21:33 2007 UTC vs.
Revision 1.83 by root, Mon Jan 28 12:24:05 2008 UTC