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

Comparing EV/EV.pm (file contents):
Revision 1.35 by root, Sat Nov 10 05:31:48 2007 UTC vs.
Revision 1.73 by root, Fri Dec 21 05:10:01 2007 UTC

…		…
39		39
40	my $w = EV::child 666, sub {	40	my $w = EV::child 666, sub {
41	my ($w, $revents) = @_;	41	my ($w, $revents) = @_;
42	my $status = $w->rstatus;	42	my $status = $w->rstatus;
43	};	43	};
		44
		45	# STAT CHANGES
		46	my $w = EV::stat "/etc/passwd", 10, sub {
		47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
		49	};
44		50
45	# MAINLOOP	51	# MAINLOOP
46	EV::loop; # loop until EV::loop_done is called or all watchers stop	52	EV::loop; # loop until EV::unloop is called or all watchers stop
47	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
48	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
49		55
50	=head1 DESCRIPTION	56	=head1 DESCRIPTION
51		57
52	This module provides an interface to libev	58	This module provides an interface to libev
53	(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.
54		65
55	=cut	66	=cut
56		67
57	package EV;	68	package EV;
58		69
59	use strict;	70	use strict;
60		71
61	BEGIN {	72	BEGIN {
62	our $VERSION = '0.7';	73	our $VERSION = '2.0';
63	use XSLoader;	74	use XSLoader;
64	XSLoader::load "EV", $VERSION;	75	XSLoader::load "EV", $VERSION;
65	}	76	}
66		77
67	@EV::Io::ISA =	78	@EV::IO::ISA =
68	@EV::Timer::ISA =	79	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	80	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	81	@EV::Signal::ISA =
		82	@EV::Child::ISA =
		83	@EV::Stat::ISA =
71	@EV::Idle::ISA =	84	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	85	@EV::Prepare::ISA =
73	@EV::Check::ISA =	86	@EV::Check::ISA =
74	@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 cna 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	=back
		132
75		133
76	=head1 BASIC INTERFACE	134	=head1 BASIC INTERFACE
77		135
78	=over 4	136	=over 4
79		137
80	=item $EV::DIED	138	=item $EV::DIED
81		139
82	Must contain a reference to a function that is called when a callback	140	Must contain a reference to a function that is called when a callback
83	throws an exception (with $@ containing thr error). The default prints an	141	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	142	informative message and continues.
85		143
86	If this callback throws an exception it will be silently ignored.	144	If this callback throws an exception it will be silently ignored.
87		145
88	=item $time = EV::time	146	=item $time = EV::time
89		147
90	Returns the current time in (fractional) seconds since the epoch.	148	Returns the current time in (fractional) seconds since the epoch.
91		149
92	=item $time = EV::now	150	=item $time = EV::now
		151
		152	=item $time = $loop->now
93		153
94	Returns the time the last event loop iteration has been started. This	154	Returns the time the last event loop iteration has been started. This
95	is the time that (relative) timers are based on, and refering to it is	155	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	156	usually faster then calling EV::time.
97		157
98	=item $method = EV::ev_method	158	=item $backend = EV::backend
		159
		160	=item $backend = $loop->backend
99		161
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	162	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	163	or EV::METHOD_EPOLL).
102		164
103	=item EV::loop [$flags]	165	=item EV::loop [$flags]
104		166
		167	=item $loop->loop ([$flags])
		168
105	Begin checking for events and calling callbacks. It returns when a	169	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::loop_done.	170	callback calls EV::unloop.
107		171
108	The $flags argument can be one of the following:	172	The $flags argument can be one of the following:
109		173
110	0 as above	174	0 as above
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	175	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	176	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		177
114	=item EV::loop_done [$how]	178	=item EV::unloop [$how]
115		179
		180	=item $loop->unloop ([$how])
		181
116	When called with no arguments or an argument of 1, makes the innermost	182	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	call to EV::loop return.	183	innermost call to EV::loop return.
118		184
119	When called with an agrument of 2, all calls to EV::loop will return as	185	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	186	fast as possible.
121		187
122	=back	188	=item $count = EV::loop_count
123		189
124	=head2 WATCHER	190	=item $count = $loop->loop_count
		191
		192	Return the number of times the event loop has polled for new
		193	events. Sometiems useful as a generation counter.
		194
		195	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		196
		197	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		198
		199	This function rolls together an I/O and a timer watcher for a single
		200	one-shot event without the need for managing a watcher object.
		201
		202	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		203	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		204	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		205	you do not want to wait for some I/O event, specify C<undef> for
		206	C<$fh_or_undef> and C<0> for C<$events>).
		207
		208	If timeout is C<undef> or negative, then there will be no
		209	timeout. Otherwise a EV::timer with this value will be started.
		210
		211	When an error occurs or either the timeout or I/O watcher triggers, then
		212	the callback will be called with the received event set (in general
		213	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		214	C<EV::WRITE> and C<EV::TIMEOUT>).
		215
		216	EV::once doesn't return anything: the watchers stay active till either
		217	of them triggers, then they will be stopped and freed, and the callback
		218	invoked.
		219
		220	=item EV::feed_fd_event ($fd, $revents)
		221
		222	=item $loop->feed_fd_event ($fd, $revents)
		223
		224	Feed an event on a file descriptor into EV. EV will react to this call as
		225	if the readyness notifications specified by C<$revents> (a combination of
		226	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		227
		228	=item EV::feed_signal_event ($signal)
		229
		230	Feed a signal event into EV. EV will react to this call as if the signal
		231	specified by C<$signal> had occured.
		232
		233	=back
		234
		235
		236	=head1 WATCHER OBJECTS
125		237
126	A watcher is an object that gets created to record your interest in some	238	A watcher is an object that gets created to record your interest in some
127	event. For instance, if you want to wait for STDIN to become readable, you	239	event. For instance, if you want to wait for STDIN to become readable, you
128	would create an EV::io watcher for that:	240	would create an EV::io watcher for that:
129		241
…		…
138	events.	250	events.
139		251
140	Each watcher type has its associated bit in revents, so you can use the	252	Each watcher type has its associated bit in revents, so you can use the
141	same callback for multiple watchers. The event mask is named after the	253	same callback for multiple watchers. The event mask is named after the
142	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	254	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
143	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	255	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
144	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	256	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
145	uses EV::TIMEOUT).	257	uses EV::TIMEOUT).
146		258
147	In the rare case where one wants to create a watcher but not start it at	259	In the rare case where one wants to create a watcher but not start it at
148	the same time, each constructor has a variant with a trailing C<_ns> in	260	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
154		266
155	Also, all methods changing some aspect of a watcher (->set, ->priority,	267	Also, all methods changing some aspect of a watcher (->set, ->priority,
156	->fh and so on) automatically stop and start it again if it is active,	268	->fh and so on) automatically stop and start it again if it is active,
157	which means pending events get lost.	269	which means pending events get lost.
158		270
159	=head2 WATCHER TYPES	271	=head2 COMMON WATCHER METHODS
160		272
161	Now lets move to the existing watcher types and asociated methods.	273	This section lists methods common to all watchers.
162
163	The following methods are available for all watchers. Then followes a
164	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
165	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
166	any type-specific methods (if any).
167		274
168	=over 4	275	=over 4
169		276
170	=item $w->start	277	=item $w->start
171		278
…		…
175		282
176	=item $w->stop	283	=item $w->stop
177		284
178	Stop a watcher if it is active. Also clear any pending events (events that	285	Stop a watcher if it is active. Also clear any pending events (events that
179	have been received but that didn't yet result in a callback invocation),	286	have been received but that didn't yet result in a callback invocation),
180	regardless of wether the watcher was active or not.	287	regardless of whether the watcher was active or not.
181		288
182	=item $bool = $w->is_active	289	=item $bool = $w->is_active
183		290
184	Returns true if the watcher is active, false otherwise.	291	Returns true if the watcher is active, false otherwise.
185		292
…		…
210	watchers with higher priority will be invoked first. The valid range of	317	watchers with higher priority will be invoked first. The valid range of
211	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	318	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
212	-2). If the priority is outside this range it will automatically be	319	-2). If the priority is outside this range it will automatically be
213	normalised to the nearest valid priority.	320	normalised to the nearest valid priority.
214		321
215	The default priority of any newly-created weatcher is 0.	322	The default priority of any newly-created watcher is 0.
216		323
		324	Note that the priority semantics have not yet been fleshed out and are
		325	subject to almost certain change.
		326
217	=item $w->trigger ($revents)	327	=item $w->invoke ($revents)
218		328
219	Call the callback now with the given event mask.	329	Call the callback now with the given event mask.
220		330
		331	=item $w->feed_event ($revents)
		332
		333	Feed some events on this watcher into EV. EV will react to this call as if
		334	the watcher had received the given C<$revents> mask.
		335
		336	=item $revents = $w->clear_pending
		337
		338	If the watcher is pending, this function returns clears its pending status
		339	and returns its C<$revents> bitset (as if its callback was invoked). If the
		340	watcher isn't pending it does nothing and returns C<0>.
		341
		342	=item $previous_state = $w->keepalive ($bool)
		343
		344	Normally, C<EV::loop> will return when there are no active watchers
		345	(which is a "deadlock" because no progress can be made anymore). This is
		346	convinient because it allows you to start your watchers (and your jobs),
		347	call C<EV::loop> once and when it returns you know that all your jobs are
		348	finished (or they forgot to register some watchers for their task :).
		349
		350	Sometimes, however, this gets in your way, for example when you the module
		351	that calls C<EV::loop> (usually the main program) is not the same module
		352	as a long-living watcher (for example a DNS client module written by
		353	somebody else even). Then you might want any outstanding requests to be
		354	handled, but you would not want to keep C<EV::loop> from returning just
		355	because you happen to have this long-running UDP port watcher.
		356
		357	In this case you can clear the keepalive status, which means that even
		358	though your watcher is active, it won't keep C<EV::loop> from returning.
		359
		360	The initial value for keepalive is true (enabled), and you cna change it
		361	any time.
		362
		363	Example: Register an I/O watcher for some UDP socket but do not keep the
		364	event loop from running just because of that watcher.
		365
		366	my $udp_socket = ...
		367	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		368	$udp_watcher->keepalive (0);
		369
		370	=back
		371
		372
		373	=head1 WATCHER TYPES
		374
		375	Each of the following subsections describes a single watcher type.
		376
		377	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		378
		379	=over 4
221		380
222	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	381	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
223		382
224	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	383	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
225		384
		385	=item $w = $loop->io 8$fileno_or_fh, $eventmask, $callback)
		386
		387	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		388
226	As long as the returned watcher object is alive, call the C<$callback>	389	As long as the returned watcher object is alive, call the C<$callback>
227	when the events specified in C<$eventmask>.	390	when at least one of events specified in C<$eventmask> occurs.
228		391
229	The $eventmask can be one or more of these constants ORed together:	392	The $eventmask can be one or more of these constants ORed together:
230		393
231	EV::READ wait until read() wouldn't block anymore	394	EV::READ wait until read() wouldn't block anymore
232	EV::WRITE wait until write() wouldn't block anymore	395	EV::WRITE wait until write() wouldn't block anymore
…		…
248		411
249	=item $old_eventmask = $w->events ($new_eventmask)	412	=item $old_eventmask = $w->events ($new_eventmask)
250		413
251	Returns the previously set event mask and optionally set a new one.	414	Returns the previously set event mask and optionally set a new one.
252		415
		416	=back
		417
		418
		419	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		420
		421	=over 4
253		422
254	=item $w = EV::timer $after, $repeat, $callback	423	=item $w = EV::timer $after, $repeat, $callback
255		424
256	=item $w = EV::timer_ns $after, $repeat, $callback	425	=item $w = EV::timer_ns $after, $repeat, $callback
257		426
258	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	427	=item $w = $loop->timer ($after, $repeat, $callback)
259	the timer will be restarted (with the $repeat value as $after) after the	428
260	callback returns.	429	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		430
		431	Calls the callback after C<$after> seconds (which may be fractional). If
		432	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		433	value as $after) after the callback returns.
261		434
262	This means that the callback would be called roughly after C<$after>	435	This means that the callback would be called roughly after C<$after>
263	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	436	seconds, and then every C<$repeat> seconds. The timer does his best not
264	callback processing is not taken into account, so the timer will slowly	437	to drift, but it will not invoke the timer more often then once per event
265	drift. If that isn't acceptable, look at EV::periodic.	438	loop iteration, and might drift in other cases. If that isn't acceptable,
		439	look at EV::periodic, which can provide long-term stable timers.
266		440
267	The timer is based on a monotonic clock, that is if somebody is sitting	441	The timer is based on a monotonic clock, that is, if somebody is sitting
268	in front of the machine while the timer is running and changes the system	442	in front of the machine while the timer is running and changes the system
269	clock, the timer will nevertheless run (roughly) the same time.	443	clock, the timer will nevertheless run (roughly) the same time.
270		444
271	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	445	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
272		446
273	=item $w->set ($after, $repeat)	447	=item $w->set ($after, $repeat)
274		448
275	Reconfigures the watcher, see the constructor above for details. Can be at	449	Reconfigures the watcher, see the constructor above for details. Can be called at
276	any time.	450	any time.
277		451
278	=item $w->again	452	=item $w->again
279		453
280	Similar to the C<start> method, but has special semantics for repeating timers:	454	Similar to the C<start> method, but has special semantics for repeating timers:
		455
		456	If the timer is active and non-repeating, it will be stopped.
281		457
282	If the timer is active and repeating, reset the timeout to occur	458	If the timer is active and repeating, reset the timeout to occur
283	C<$repeat> seconds after now.	459	C<$repeat> seconds after now.
284		460
285	If the timer is active and non-repeating, it will be stopped.
286
287	If the timer is in active and repeating, start it.	461	If the timer is inactive and repeating, start it using the repeat value.
288		462
289	Otherwise do nothing.	463	Otherwise do nothing.
290		464
291	This behaviour is useful when you have a timeout for some IO	465	This behaviour is useful when you have a timeout for some IO
292	operation. You create a timer object with the same value for C<$after> and	466	operation. You create a timer object with the same value for C<$after> and
293	C<$repeat>, and then, in the read/write watcher, run the C<again> method	467	C<$repeat>, and then, in the read/write watcher, run the C<again> method
294	on the timeout.	468	on the timeout.
295		469
		470	=back
		471
		472
		473	=head3 PERIODIC WATCHERS - to cron or not to cron?
		474
		475	=over 4
296		476
297	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	477	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
298		478
299	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	479	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		480
		481	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		482
		483	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
300		484
301	Similar to EV::timer, but is not based on relative timeouts but on	485	Similar to EV::timer, but is not based on relative timeouts but on
302	absolute times. Apart from creating "simple" timers that trigger "at" the	486	absolute times. Apart from creating "simple" timers that trigger "at" the
303	specified time, it can also be used for non-drifting absolute timers and	487	specified time, it can also be used for non-drifting absolute timers and
304	more complex, cron-like, setups that are not adversely affected by time	488	more complex, cron-like, setups that are not adversely affected by time
…		…
336	possible time where C<$time = $at (mod $interval)>, regardless of any time	520	possible time where C<$time = $at (mod $interval)>, regardless of any time
337	jumps.	521	jumps.
338		522
339	=item * manual reschedule mode ($reschedule_cb = coderef)	523	=item * manual reschedule mode ($reschedule_cb = coderef)
340		524
341	In this mode $interval and $at are both being ignored. Instead, each time	525	In this mode $interval and $at are both being ignored. Instead, each
342	the periodic watcher gets scheduled, the first callback ($reschedule_cb)	526	time the periodic watcher gets scheduled, the reschedule callback
343	will be called with the watcher as first, and the current time as second	527	($reschedule_cb) will be called with the watcher as first, and the current
344	argument.	528	time as second argument.
345		529
346	I<This callback MUST NOT stop or destroy this or any other periodic	530	I<This callback MUST NOT stop or destroy this or any other periodic
347	watcher, ever>. If you need to stop it, return 1e30 and stop it	531	watcher, ever>. If you need to stop it, return 1e30 and stop it
348	afterwards.	532	afterwards.
349		533
…		…
372		556
373	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	557	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
374		558
375	=item $w->set ($at, $interval, $reschedule_cb)	559	=item $w->set ($at, $interval, $reschedule_cb)
376		560
377	Reconfigures the watcher, see the constructor above for details. Can be at	561	Reconfigures the watcher, see the constructor above for details. Can be called at
378	any time.	562	any time.
379		563
380	=item $w->again	564	=item $w->again
381		565
382	Simply stops and starts the watcher again.	566	Simply stops and starts the watcher again.
383		567
		568	=item $time = $w->at
		569
		570	Return the time that the watcher is expected to trigger next.
		571
		572	=back
		573
		574
		575	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		576
		577	=over 4
384		578
385	=item $w = EV::signal $signal, $callback	579	=item $w = EV::signal $signal, $callback
386		580
387	=item $w = EV::signal_ns $signal, $callback	581	=item $w = EV::signal_ns $signal, $callback
388		582
389	Call the callback when $signal is received (the signal can be specified	583	Call the callback when $signal is received (the signal can be specified by
390	by number or by name, just as with kill or %SIG).	584	number or by name, just as with C<kill> or C<%SIG>).
391		585
392	EV will grab the signal for the process (the kernel only allows one	586	EV will grab the signal for the process (the kernel only allows one
393	component to receive a signal at a time) when you start a signal watcher,	587	component to receive a signal at a time) when you start a signal watcher,
394	and removes it again when you stop it. Perl does the same when you	588	and removes it again when you stop it. Perl does the same when you
395	add/remove callbacks to %SIG, so watch out.	589	add/remove callbacks to C<%SIG>, so watch out.
396		590
397	You can have as many signal watchers per signal as you want.	591	You can have as many signal watchers per signal as you want.
398		592
399	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	593	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
400		594
401	=item $w->set ($signal)	595	=item $w->set ($signal)
402		596
403	Reconfigures the watcher, see the constructor above for details. Can be at	597	Reconfigures the watcher, see the constructor above for details. Can be
404	any time.	598	called at any time.
405		599
406	=item $current_signum = $w->signal	600	=item $current_signum = $w->signal
407		601
408	=item $old_signum = $w->signal ($new_signal)	602	=item $old_signum = $w->signal ($new_signal)
409		603
410	Returns the previously set signal (always as a number not name) and	604	Returns the previously set signal (always as a number not name) and
411	optionally set a new one.	605	optionally set a new one.
412		606
		607	=back
		608
		609
		610	=head3 CHILD WATCHERS - watch out for process status changes
		611
		612	=over 4
413		613
414	=item $w = EV::child $pid, $callback	614	=item $w = EV::child $pid, $callback
415		615
416	=item $w = EV::child_ns $pid, $callback	616	=item $w = EV::child_ns $pid, $callback
417		617
		618	=item $w = $loop->child ($pid, $callback)
		619
		620	=item $w = $loop->child_ns ($pid, $callback)
		621
418	Call the callback when a status change for pid C<$pid> (or any pid	622	Call the callback when a status change for pid C<$pid> (or any pid if
419	if C<$pid> is 0) has been received. More precisely: when the process	623	C<$pid> is 0) has been received. More precisely: when the process receives
420	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	624	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
421	changed/zombie children and call the callback.	625	changed/zombie children and call the callback.
422		626
423	You can access both status and pid by using the C<rstatus> and C<rpid>	627	It is valid (and fully supported) to install a child watcher after a child
424	methods on the watcher object.	628	has exited but before the event loop has started its next iteration (for
		629	example, first you C<fork>, then the new child process might exit, and
		630	only then do you install a child watcher in the parent for the new pid).
425		631
		632	You can access both exit (or tracing) status and pid by using the
		633	C<rstatus> and C<rpid> methods on the watcher object.
		634
426	You can have as many pid watchers per pid as you want.	635	You can have as many pid watchers per pid as you want, they will all be
		636	called.
427		637
428	The C<child_ns> variant doesn't start (activate) the newly created watcher.	638	The C<child_ns> variant doesn't start (activate) the newly created watcher.
429		639
430	=item $w->set ($pid)	640	=item $w->set ($pid)
431		641
432	Reconfigures the watcher, see the constructor above for details. Can be at	642	Reconfigures the watcher, see the constructor above for details. Can be called at
433	any time.	643	any time.
434		644
435	=item $current_pid = $w->pid	645	=item $current_pid = $w->pid
436		646
437	=item $old_pid = $w->pid ($new_pid)	647	=item $old_pid = $w->pid ($new_pid)
…		…
446	=item $pid = $w->rpid	656	=item $pid = $w->rpid
447		657
448	Return the pid of the awaited child (useful when you have installed a	658	Return the pid of the awaited child (useful when you have installed a
449	watcher for all pids).	659	watcher for all pids).
450		660
		661	=back
		662
		663
		664	=head3 STAT WATCHERS - did the file attributes just change?
		665
		666	=over 4
		667
		668	=item $w = EV::stat $path, $interval, $callback
		669
		670	=item $w = EV::stat_ns $path, $interval, $callback
		671
		672	=item $w = $loop->stat ($path, $interval, $callback)
		673
		674	=item $w = $loop->stat_ns ($path, $interval, $callback)
		675
		676	Call the callback when a file status change has been detected on
		677	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		678	to "path does not exist" is a status change like any other.
		679
		680	The C<$interval> is a recommended polling interval for systems where
		681	OS-supported change notifications don't exist or are not supported. If
		682	you use C<0> then an unspecified default is used (which is highly
		683	recommended!), which is to be expected to be around five seconds usually.
		684
		685	This watcher type is not meant for massive numbers of stat watchers,
		686	as even with OS-supported change notifications, this can be
		687	resource-intensive.
		688
		689	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		690
		691	=item ... = $w->stat
		692
		693	This call is very similar to the perl C<stat> built-in: It stats (using
		694	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		695	well as EV's idea of the current stat values) to the values found.
		696
		697	In scalar context, a boolean is return indicating success or failure of
		698	the stat. In list context, the same 13-value list as with stat is returned
		699	(except that the blksize and blocks fields are not reliable).
		700
		701	In the case of an error, errno is set to C<ENOENT> (regardless of the
		702	actual error value) and the C<nlink> value is forced to zero (if the stat
		703	was successful then nlink is guaranteed to be non-zero).
		704
		705	See also the next two entries for more info.
		706
		707	=item ... = $w->attr
		708
		709	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		710	the values most recently detected by EV. See the next entry for more info.
		711
		712	=item ... = $w->prev
		713
		714	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		715	the previous set of values, before the change.
		716
		717	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		718	to the values found I<before> a change was detected, while C<< $w->attr >>
		719	returns the values found leading to the change detection. The difference (if any)
		720	between C<prev> and C<attr> is what triggered the callback.
		721
		722	If you did something to the filesystem object and do not want to trigger
		723	yet another change, you can call C<stat> to update EV's idea of what the
		724	current attributes are.
		725
		726	=item $w->set ($path, $interval)
		727
		728	Reconfigures the watcher, see the constructor above for details. Can be
		729	called at any time.
		730
		731	=item $current_path = $w->path
		732
		733	=item $old_path = $w->path ($new_path)
		734
		735	Returns the previously set path and optionally set a new one.
		736
		737	=item $current_interval = $w->interval
		738
		739	=item $old_interval = $w->interval ($new_interval)
		740
		741	Returns the previously set interval and optionally set a new one. Can be
		742	used to query the actual interval used.
		743
		744	=back
		745
		746
		747	=head3 IDLE WATCHERS - when you've got nothing better to do...
		748
		749	=over 4
451		750
452	=item $w = EV::idle $callback	751	=item $w = EV::idle $callback
453		752
454	=item $w = EV::idle_ns $callback	753	=item $w = EV::idle_ns $callback
455		754
456	Call the callback when there are no pending io, timer/periodic, signal or	755	=item $w = $loop->idle ($callback)
457	child events, i.e. when the process is idle.	756
		757	=item $w = $loop->idle_ns ($callback)
		758
		759	Call the callback when there are no other pending watchers of the same or
		760	higher priority (excluding check, prepare and other idle watchers of the
		761	same or lower priority, of course). They are called idle watchers because
		762	when the watcher is the highest priority pending event in the process, the
		763	process is considered to be idle at that priority.
		764
		765	If you want a watcher that is only ever called when I<no> other events are
		766	outstanding you have to set the priority to C<EV::MINPRI>.
458		767
459	The process will not block as long as any idle watchers are active, and	768	The process will not block as long as any idle watchers are active, and
460	they will be called repeatedly until stopped.	769	they will be called repeatedly until stopped.
461		770
		771	For example, if you have idle watchers at priority C<0> and C<1>, and
		772	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		773	and the I/O watcher will always run when ready. Only when the idle watcher
		774	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		775	pending with the C<0>-priority idle watcher be invoked.
		776
462	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	777	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
463		778
		779	=back
		780
		781
		782	=head3 PREPARE WATCHERS - customise your event loop!
		783
		784	=over 4
464		785
465	=item $w = EV::prepare $callback	786	=item $w = EV::prepare $callback
466		787
467	=item $w = EV::prepare_ns $callback	788	=item $w = EV::prepare_ns $callback
		789
		790	=item $w = $loop->prepare ($callback)
		791
		792	=item $w = $loop->prepare_ns 8$callback)
468		793
469	Call the callback just before the process would block. You can still	794	Call the callback just before the process would block. You can still
470	create/modify any watchers at this point.	795	create/modify any watchers at this point.
471		796
472	See the EV::check watcher, below, for explanations and an example.	797	See the EV::check watcher, below, for explanations and an example.
473		798
474	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	799	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
475		800
		801	=back
		802
		803
		804	=head3 CHECK WATCHERS - customise your event loop even more!
		805
		806	=over 4
476		807
477	=item $w = EV::check $callback	808	=item $w = EV::check $callback
478		809
479	=item $w = EV::check_ns $callback	810	=item $w = EV::check_ns $callback
		811
		812	=item $w = $loop->check ($callback)
		813
		814	=item $w = $loop->check_ns ($callback)
480		815
481	Call the callback just after the process wakes up again (after it has	816	Call the callback just after the process wakes up again (after it has
482	gathered events), but before any other callbacks have been invoked.	817	gathered events), but before any other callbacks have been invoked.
483		818
484	This is used to integrate other event-based software into the EV	819	This is used to integrate other event-based software into the EV
…		…
492	# do nothing unless active	827	# do nothing unless active
493	$dispatcher->{_event_queue_h}	828	$dispatcher->{_event_queue_h}
494	or return;	829	or return;
495		830
496	# make the dispatcher handle any outstanding stuff	831	# make the dispatcher handle any outstanding stuff
		832	... not shown
497		833
498	# create an IO watcher for each and every socket	834	# create an I/O watcher for each and every socket
499	@snmp_watcher = (	835	@snmp_watcher = (
500	(map { EV::io $_, EV::READ, sub { } }	836	(map { EV::io $_, EV::READ, sub { } }
501	keys %{ $dispatcher->{_descriptors} }),	837	keys %{ $dispatcher->{_descriptors} }),
		838
		839	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		840	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		841	0, sub { },
502	);	842	);
503
504	# if there are any timeouts, also create a timer
505	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
506	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
507	};	843	};
508		844
509	The callbacks are irrelevant, the only purpose of those watchers is	845	The callbacks are irrelevant (and are not even being called), the
510	to wake up the process as soon as one of those events occurs (socket	846	only purpose of those watchers is to wake up the process as soon as
511	readable, or timer timed out). The corresponding EV::check watcher will then	847	one of those events occurs (socket readable, or timer timed out). The
512	clean up:	848	corresponding EV::check watcher will then clean up:
513		849
514	our $snmp_check = EV::check sub {	850	our $snmp_check = EV::check sub {
515	# destroy all watchers	851	# destroy all watchers
516	@snmp_watcher = ();	852	@snmp_watcher = ();
517		853
518	# make the dispatcher handle any new stuff	854	# make the dispatcher handle any new stuff
		855	... not shown
519	};	856	};
520		857
521	The callbacks of the created watchers will not be called as the watchers	858	The callbacks of the created watchers will not be called as the watchers
522	are destroyed before this cna happen (remember EV::check gets called	859	are destroyed before this cna happen (remember EV::check gets called
523	first).	860	first).
524		861
525	The C<check_ns> variant doesn't start (activate) the newly created watcher.	862	The C<check_ns> variant doesn't start (activate) the newly created watcher.
526		863
527	=back	864	=back
528		865
		866
		867	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		868
		869	Fork watchers are called when a C<fork ()> was detected. The invocation
		870	is done before the event loop blocks next and before C<check> watchers
		871	are being called, and only in the child after the fork.
		872
		873	=over 4
		874
		875	=item $w = EV::fork $callback
		876
		877	=item $w = EV::fork_ns $callback
		878
		879	=item $w = $loop->fork ($callback)
		880
		881	=item $w = $loop->fork_ns ($callback)
		882
		883	Call the callback before the event loop is resumed in the child process
		884	after a fork.
		885
		886	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		887
		888	=back
		889
		890
		891	=head1 PERL SIGNALS
		892
		893	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		894	with EV is as the same as any other C library: Perl-signals will only be
		895	handled when Perl runs, which means your signal handler might be invoked
		896	only the next time an event callback is invoked.
		897
		898	The solution is to use EV signal watchers (see C<EV::signal>), which will
		899	ensure proper operations with regards to other event watchers.
		900
		901	If you cannot do this for whatever reason, you can also force a watcher
		902	to be called on every event loop iteration by installing a C<EV::check>
		903	watcher:
		904
		905	my $async_check = EV::check sub { };
		906
		907	This ensures that perl shortly gets into control for a short time, and
		908	also ensures slower overall operation.
		909
529	=head1 THREADS	910	=head1 THREADS
530		911
531	Threads are not supported by this in any way. Perl pseudo-threads is evil	912	Threads are not supported by this module in any way. Perl pseudo-threads
532	stuff and must die.	913	is evil stuff and must die. As soon as Perl gains real threads I will work
		914	on thread support for it.
		915
		916	=head1 FORK
		917
		918	Most of the "improved" event delivering mechanisms of modern operating
		919	systems have quite a few problems with fork(2) (to put it bluntly: it is
		920	not supported and usually destructive). Libev makes it possible to work
		921	around this by having a function that recreates the kernel state after
		922	fork in the child.
		923
		924	On non-win32 platforms, this module requires the pthread_atfork
		925	functionality to do this automatically for you. This function is quite
		926	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		927	negligible, because everything the function currently does is set a flag
		928	that is checked only when the event loop gets used the next time, so when
		929	you do fork but not use EV, the overhead is minimal.
		930
		931	On win32, there is no notion of fork so all this doesn't apply, of course.
533		932
534	=cut	933	=cut
535		934
536	our $DIED = sub {	935	our $DIED = sub {
537	warn "EV: error in callback (ignoring): $@";	936	warn "EV: error in callback (ignoring): $@";
538	};	937	};
539		938
540	default_loop	939	default_loop
541	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	940	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
542		941
543	1;	942	1;
544		943
545	=head1 SEE ALSO	944	=head1 SEE ALSO
546		945
547	L<EV::DNS>, L<EV::AnyEvent>.	946	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		947	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		948	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP).
548		949
549	=head1 AUTHOR	950	=head1 AUTHOR
550		951
551	Marc Lehmann <schmorp@schmorp.de>	952	Marc Lehmann <schmorp@schmorp.de>
552	http://home.schmorp.de/	953	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.35 by root, Sat Nov 10 05:31:48 2007 UTC vs. Revision 1.73 by root, Fri Dec 21 05:10:01 2007 UTC

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Revision 1.35 by root, Sat Nov 10 05:31:48 2007 UTC vs.
Revision 1.73 by root, Fri Dec 21 05:10:01 2007 UTC