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

Comparing EV/EV.pm (file contents):
Revision 1.54 by root, Tue Nov 27 07:27:10 2007 UTC vs.
Revision 1.86 by root, Wed Apr 2 11:00:58 2008 UTC

…		…
35	warn "sigquit received\n";	35	warn "sigquit received\n";
36	};	36	};
37		37
38	# CHILD/PID STATUS CHANGES	38	# CHILD/PID STATUS CHANGES
39		39
40	my $w = EV::child 666, sub {	40	my $w = EV::child 666, 0, sub {
41	my ($w, $revents) = @_;	41	my ($w, $revents) = @_;
42	my $status = $w->rstatus;	42	my $status = $w->rstatus;
43	};	43	};
44		44
45	# STAT CHANGES	45	# STAT CHANGES
…		…
58	This module provides an interface to libev	58	This module provides an interface to libev
59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60	below is comprehensive, one might also consult the documentation of libev	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	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	62	watcher semantics or some discussion on the available backends, or how to
63	force a specific backend with C<LIBEV_FLAGS>.	63	force a specific backend with C<LIBEV_FLAGS>, or just about in any case
		64	because it has much more detailed information.
64		65
65	=cut	66	=cut
66		67
67	package EV;	68	package EV;
68		69
69	use strict;	70	use strict;
70		71
71	BEGIN {	72	BEGIN {
72	our $VERSION = '1.4';	73	our $VERSION = '3.2';
73	use XSLoader;	74	use XSLoader;
74	XSLoader::load "EV", $VERSION;	75	XSLoader::load "EV", $VERSION;
75	}	76	}
76		77
77	@EV::IO::ISA =	78	@EV::IO::ISA =
78	@EV::Timer::ISA =	79	@EV::Timer::ISA =
79	@EV::Periodic::ISA =	80	@EV::Periodic::ISA =
80	@EV::Signal::ISA =	81	@EV::Signal::ISA =
		82	@EV::Child::ISA =
		83	@EV::Stat::ISA =
81	@EV::Idle::ISA =	84	@EV::Idle::ISA =
82	@EV::Prepare::ISA =	85	@EV::Prepare::ISA =
83	@EV::Check::ISA =	86	@EV::Check::ISA =
84	@EV::Child::ISA =
85	@EV::Embed::ISA =	87	@EV::Embed::ISA =
86	@EV::Stat::ISA = "EV::Watcher";	88	@EV::Fork::ISA =
		89	@EV::Async::ISA =
		90	"EV::Watcher";
		91
		92	@EV::Loop::Default::ISA = "EV::Loop";
		93
		94	=head1 EVENT LOOPS
		95
		96	EV supports multiple event loops: There is a single "default event loop"
		97	that can handle everything including signals and child watchers, and any
		98	number of "dynamic event loops" that can use different backends (with
		99	various limitations), but no child and signal watchers.
		100
		101	You do not have to do anything to create the default event loop: When
		102	the module is loaded a suitable backend is selected on the premise of
		103	selecting a working backend (which for example rules out kqueue on most
		104	BSDs). Modules should, unless they have "special needs" always use the
		105	default loop as this is fastest (perl-wise), best supported by other
		106	modules (e.g. AnyEvent or Coro) and most portable event loop.
		107
		108	For specific programs you can create additional event loops dynamically.
		109
		110	=over 4
		111
		112	=item $loop = new EV::loop [$flags]
		113
		114	Create a new event loop as per the specified flags. Please refer to the
		115	C<ev_loop_new ()> function description in the libev documentation
		116	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		117	for more info.
		118
		119	The loop will automatically be destroyed when it is no longer referenced
		120	by any watcher and the loop object goes out of scope.
		121
		122	Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop
		123	is protected by this module.
		124
		125	=item $loop->loop_fork
		126
		127	Must be called after a fork in the child, before entering or continuing
		128	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		129	this fucntion automatically, at some performance loss (refer to the libev
		130	documentation).
		131
		132	=item $loop = EV::default_loop [$flags]
		133
		134	Return the default loop (which is a singleton object).
		135
		136	=back
		137
87		138
88	=head1 BASIC INTERFACE	139	=head1 BASIC INTERFACE
89		140
90	=over 4	141	=over 4
91		142
92	=item $EV::DIED	143	=item $EV::DIED
93		144
94	Must contain a reference to a function that is called when a callback	145	Must contain a reference to a function that is called when a callback
95	throws an exception (with $@ containing thr error). The default prints an	146	throws an exception (with $@ containing the error). The default prints an
96	informative message and continues.	147	informative message and continues.
97		148
98	If this callback throws an exception it will be silently ignored.	149	If this callback throws an exception it will be silently ignored.
99		150
		151	=item $flags = EV::supported_backends
		152
		153	=item $flags = EV::recommended_backends
		154
		155	=item $flags = EV::embeddable_backends
		156
		157	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		158	instance of EV, the set of recommended backends (supposed to be good) for
		159	this platform and the set of embeddable backends (see EMBED WATCHERS).
		160
		161	=item EV::sleep $seconds
		162
		163	Block the process for the given number of (fractional) seconds.
		164
100	=item $time = EV::time	165	=item $time = EV::time
101		166
102	Returns the current time in (fractional) seconds since the epoch.	167	Returns the current time in (fractional) seconds since the epoch.
103		168
104	=item $time = EV::now	169	=item $time = EV::now
		170
		171	=item $time = $loop->now
105		172
106	Returns the time the last event loop iteration has been started. This	173	Returns the time the last event loop iteration has been started. This
107	is the time that (relative) timers are based on, and refering to it is	174	is the time that (relative) timers are based on, and refering to it is
108	usually faster then calling EV::time.	175	usually faster then calling EV::time.
109		176
110	=item $method = EV::method	177	=item $backend = EV::backend
		178
		179	=item $backend = $loop->backend
111		180
112	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	181	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
113	or EV::METHOD_EPOLL).	182	or EV::METHOD_EPOLL).
114		183
115	=item EV::loop [$flags]	184	=item EV::loop [$flags]
		185
		186	=item $loop->loop ([$flags])
116		187
117	Begin checking for events and calling callbacks. It returns when a	188	Begin checking for events and calling callbacks. It returns when a
118	callback calls EV::unloop.	189	callback calls EV::unloop.
119		190
120	The $flags argument can be one of the following:	191	The $flags argument can be one of the following:
…		…
123	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	194	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
124	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	195	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
125		196
126	=item EV::unloop [$how]	197	=item EV::unloop [$how]
127		198
		199	=item $loop->unloop ([$how])
		200
128	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	201	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
129	innermost call to EV::loop return.	202	innermost call to EV::loop return.
130		203
131	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	204	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
132	fast as possible.	205	fast as possible.
133		206
		207	=item $count = EV::loop_count
		208
		209	=item $count = $loop->loop_count
		210
		211	Return the number of times the event loop has polled for new
		212	events. Sometiems useful as a generation counter.
		213
134	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)	214	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		215
		216	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
135		217
136	This function rolls together an I/O and a timer watcher for a single	218	This function rolls together an I/O and a timer watcher for a single
137	one-shot event without the need for managing a watcher object.	219	one-shot event without the need for managing a watcher object.
138		220
139	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>	221	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
…		…
145	If timeout is C<undef> or negative, then there will be no	227	If timeout is C<undef> or negative, then there will be no
146	timeout. Otherwise a EV::timer with this value will be started.	228	timeout. Otherwise a EV::timer with this value will be started.
147		229
148	When an error occurs or either the timeout or I/O watcher triggers, then	230	When an error occurs or either the timeout or I/O watcher triggers, then
149	the callback will be called with the received event set (in general	231	the callback will be called with the received event set (in general
150	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,	232	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
151	C<EV::WRITE> and C<EV::TIMEOUT>).	233	C<EV::WRITE> and C<EV::TIMEOUT>).
152		234
153	EV::once doesn't return anything: the watchers stay active till either	235	EV::once doesn't return anything: the watchers stay active till either
154	of them triggers, then they will be stopped and freed, and the callback	236	of them triggers, then they will be stopped and freed, and the callback
155	invoked.	237	invoked.
156		238
157	=back	239	=item EV::feed_fd_event ($fd, $revents)
158		240
		241	=item $loop->feed_fd_event ($fd, $revents)
		242
		243	Feed an event on a file descriptor into EV. EV will react to this call as
		244	if the readyness notifications specified by C<$revents> (a combination of
		245	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		246
		247	=item EV::feed_signal_event ($signal)
		248
		249	Feed a signal event into EV. EV will react to this call as if the signal
		250	specified by C<$signal> had occured.
		251
		252	=item EV::set_io_collect_interval $time
		253
		254	=item $loop->set_io_collect_interval ($time)
		255
		256	=item EV::set_timeout_collect_interval $time
		257
		258	=item $loop->set_timeout_collect_interval ($time)
		259
		260	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		261	wait interval for timer events. See the libev documentation at
		262	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		263	a more detailed discussion.
		264
		265	=back
		266
		267
159	=head2 WATCHER OBJECTS	268	=head1 WATCHER OBJECTS
160		269
161	A watcher is an object that gets created to record your interest in some	270	A watcher is an object that gets created to record your interest in some
162	event. For instance, if you want to wait for STDIN to become readable, you	271	event. For instance, if you want to wait for STDIN to become readable, you
163	would create an EV::io watcher for that:	272	would create an EV::io watcher for that:
164		273
165	my $watcher = EV::io *STDIN, EV::READ, sub {	274	my $watcher = EV::io *STDIN, EV::READ, sub {
166	my ($watcher, $revents) = @_;	275	my ($watcher, $revents) = @_;
167	warn "yeah, STDIN should not be readable without blocking!\n"	276	warn "yeah, STDIN should now be readable without blocking!\n"
168	};	277	};
169		278
170	All watchers can be active (waiting for events) or inactive (paused). Only	279	All watchers can be active (waiting for events) or inactive (paused). Only
171	active watchers will have their callbacks invoked. All callbacks will be	280	active watchers will have their callbacks invoked. All callbacks will be
172	called with at least two arguments: the watcher and a bitmask of received	281	called with at least two arguments: the watcher and a bitmask of received
173	events.	282	events.
174		283
175	Each watcher type has its associated bit in revents, so you can use the	284	Each watcher type has its associated bit in revents, so you can use the
176	same callback for multiple watchers. The event mask is named after the	285	same callback for multiple watchers. The event mask is named after the
177	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	286	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
178	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	287	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
179	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	288	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
180	uses EV::TIMEOUT).	289	uses EV::TIMEOUT).
181		290
182	In the rare case where one wants to create a watcher but not start it at	291	In the rare case where one wants to create a watcher but not start it at
183	the same time, each constructor has a variant with a trailing C<_ns> in	292	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
205		314
206	=item $w->stop	315	=item $w->stop
207		316
208	Stop a watcher if it is active. Also clear any pending events (events that	317	Stop a watcher if it is active. Also clear any pending events (events that
209	have been received but that didn't yet result in a callback invocation),	318	have been received but that didn't yet result in a callback invocation),
210	regardless of wether the watcher was active or not.	319	regardless of whether the watcher was active or not.
211		320
212	=item $bool = $w->is_active	321	=item $bool = $w->is_active
213		322
214	Returns true if the watcher is active, false otherwise.	323	Returns true if the watcher is active, false otherwise.
215		324
…		…
245	The default priority of any newly-created watcher is 0.	354	The default priority of any newly-created watcher is 0.
246		355
247	Note that the priority semantics have not yet been fleshed out and are	356	Note that the priority semantics have not yet been fleshed out and are
248	subject to almost certain change.	357	subject to almost certain change.
249		358
250	=item $w->trigger ($revents)	359	=item $w->invoke ($revents)
251		360
252	Call the callback now with the given event mask.	361	Call the callback now with the given event mask.
		362
		363	=item $w->feed_event ($revents)
		364
		365	Feed some events on this watcher into EV. EV will react to this call as if
		366	the watcher had received the given C<$revents> mask.
		367
		368	=item $revents = $w->clear_pending
		369
		370	If the watcher is pending, this function clears its pending status and
		371	returns its C<$revents> bitset (as if its callback was invoked). If the
		372	watcher isn't pending it does nothing and returns C<0>.
253		373
254	=item $previous_state = $w->keepalive ($bool)	374	=item $previous_state = $w->keepalive ($bool)
255		375
256	Normally, C<EV::loop> will return when there are no active watchers	376	Normally, C<EV::loop> will return when there are no active watchers
257	(which is a "deadlock" because no progress can be made anymore). This is	377	(which is a "deadlock" because no progress can be made anymore). This is
258	convinient because it allows you to start your watchers (and your jobs),	378	convinient because it allows you to start your watchers (and your jobs),
259	call C<EV::loop> once and when it returns you know that all your jobs are	379	call C<EV::loop> once and when it returns you know that all your jobs are
260	finished (or they forgot to register some watchers for their task :).	380	finished (or they forgot to register some watchers for their task :).
261		381
262	Sometimes, however, this gets in your way, for example when you the module	382	Sometimes, however, this gets in your way, for example when the module
263	that calls C<EV::loop> (usually the main program) is not the same module	383	that calls C<EV::loop> (usually the main program) is not the same module
264	as a long-living watcher (for example a DNS client module written by	384	as a long-living watcher (for example a DNS client module written by
265	somebody else even). Then you might want any outstanding requests to be	385	somebody else even). Then you might want any outstanding requests to be
266	handled, but you would not want to keep C<EV::loop> from returning just	386	handled, but you would not want to keep C<EV::loop> from returning just
267	because you happen to have this long-running UDP port watcher.	387	because you happen to have this long-running UDP port watcher.
…		…
270	though your watcher is active, it won't keep C<EV::loop> from returning.	390	though your watcher is active, it won't keep C<EV::loop> from returning.
271		391
272	The initial value for keepalive is true (enabled), and you cna change it	392	The initial value for keepalive is true (enabled), and you cna change it
273	any time.	393	any time.
274		394
275	Example: Register an IO watcher for some UDP socket but do not keep the	395	Example: Register an I/O watcher for some UDP socket but do not keep the
276	event loop from running just because of that watcher.	396	event loop from running just because of that watcher.
277		397
278	my $udp_socket = ...	398	my $udp_socket = ...
279	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };	399	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
280	$udp_watcher->keepalive (0);	400	$1000udp_watcher->keepalive (0);
281		401
282	=back	402	=item $loop = $w->loop
283		403
		404	Return the loop that this watcher is attached to.
284		405
		406	=back
		407
		408
285	=head2 WATCHER TYPES	409	=head1 WATCHER TYPES
286		410
287	Each of the following subsections describes a single watcher type.	411	Each of the following subsections describes a single watcher type.
288		412
289	=head3 IO WATCHERS - is this file descriptor readable or writable?	413	=head3 I/O WATCHERS - is this file descriptor readable or writable?
290		414
291	=over 4	415	=over 4
292		416
293	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	417	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
294		418
295	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	419	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		420
		421	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		422
		423	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
296		424
297	As long as the returned watcher object is alive, call the C<$callback>	425	As long as the returned watcher object is alive, call the C<$callback>
298	when at least one of events specified in C<$eventmask> occurs.	426	when at least one of events specified in C<$eventmask> occurs.
299		427
300	The $eventmask can be one or more of these constants ORed together:	428	The $eventmask can be one or more of these constants ORed together:
…		…
329	=over 4	457	=over 4
330		458
331	=item $w = EV::timer $after, $repeat, $callback	459	=item $w = EV::timer $after, $repeat, $callback
332		460
333	=item $w = EV::timer_ns $after, $repeat, $callback	461	=item $w = EV::timer_ns $after, $repeat, $callback
		462
		463	=item $w = $loop->timer ($after, $repeat, $callback)
		464
		465	=item $w = $loop->timer_ns ($after, $repeat, $callback)
334		466
335	Calls the callback after C<$after> seconds (which may be fractional). If	467	Calls the callback after C<$after> seconds (which may be fractional). If
336	C<$repeat> is non-zero, the timer will be restarted (with the $repeat	468	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
337	value as $after) after the callback returns.	469	value as $after) after the callback returns.
338		470
…		…
379	=over 4	511	=over 4
380		512
381	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	513	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
382		514
383	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	515	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		516
		517	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		518
		519	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
384		520
385	Similar to EV::timer, but is not based on relative timeouts but on	521	Similar to EV::timer, but is not based on relative timeouts but on
386	absolute times. Apart from creating "simple" timers that trigger "at" the	522	absolute times. Apart from creating "simple" timers that trigger "at" the
387	specified time, it can also be used for non-drifting absolute timers and	523	specified time, it can also be used for non-drifting absolute timers and
388	more complex, cron-like, setups that are not adversely affected by time	524	more complex, cron-like, setups that are not adversely affected by time
…		…
398	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	534	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
399	will not adjust when a time jump occurs, that is, if it is to be run	535	will not adjust when a time jump occurs, that is, if it is to be run
400	at January 1st 2011 then it will run when the system time reaches or	536	at January 1st 2011 then it will run when the system time reaches or
401	surpasses this time.	537	surpasses this time.
402		538
403	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	539	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
404		540
405	In this mode the watcher will always be scheduled to time out at the	541	In this mode the watcher will always be scheduled to time out at the
406	next C<$at + N * $interval> time (for some integer N) and then repeat,	542	next C<$at + N * $interval> time (for some integer N) and then repeat,
407	regardless of any time jumps.	543	regardless of any time jumps.
408		544
…		…
463		599
464	=item $w->again	600	=item $w->again
465		601
466	Simply stops and starts the watcher again.	602	Simply stops and starts the watcher again.
467		603
		604	=item $time = $w->at
		605
		606	Return the time that the watcher is expected to trigger next.
		607
468	=back	608	=back
469		609
470		610
471	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!	611	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
472		612
…		…
505		645
506	=head3 CHILD WATCHERS - watch out for process status changes	646	=head3 CHILD WATCHERS - watch out for process status changes
507		647
508	=over 4	648	=over 4
509		649
510	=item $w = EV::child $pid, $callback	650	=item $w = EV::child $pid, $trace, $callback
511		651
512	=item $w = EV::child_ns $pid, $callback	652	=item $w = EV::child_ns $pid, $trace, $callback
513		653
		654	=item $w = $loop->child ($pid, $trace, $callback)
		655
		656	=item $w = $loop->child_ns ($pid, $trace, $callback)
		657
514	Call the callback when a status change for pid C<$pid> (or any pid if	658	Call the callback when a status change for pid C<$pid> (or any pid
515	C<$pid> is 0) has been received. More precisely: when the process receives	659	if C<$pid> is 0) has been received (a status change happens when the
		660	process terminates or is killed, or, when trace is true, additionally when
		661	it is stopped or continued). More precisely: when the process receives
516	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all	662	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
517	changed/zombie children and call the callback.	663	changed/zombie children and call the callback.
518		664
519	It is valid (and fully supported) to install a child watcher after a child	665	It is valid (and fully supported) to install a child watcher after a child
520	has exited but before the event loop has started its next iteration (for	666	has exited but before the event loop has started its next iteration (for
…		…
527	You can have as many pid watchers per pid as you want, they will all be	673	You can have as many pid watchers per pid as you want, they will all be
528	called.	674	called.
529		675
530	The C<child_ns> variant doesn't start (activate) the newly created watcher.	676	The C<child_ns> variant doesn't start (activate) the newly created watcher.
531		677
532	=item $w->set ($pid)	678	=item $w->set ($pid, $trace)
533		679
534	Reconfigures the watcher, see the constructor above for details. Can be called at	680	Reconfigures the watcher, see the constructor above for details. Can be called at
535	any time.	681	any time.
536		682
537	=item $current_pid = $w->pid	683	=item $current_pid = $w->pid
538		684
539	=item $old_pid = $w->pid ($new_pid)
540
541	Returns the previously set process id and optionally set a new one.	685	Returns the previously set process id and optionally set a new one.
542		686
543	=item $exit_status = $w->rstatus	687	=item $exit_status = $w->rstatus
544		688
545	Return the exit/wait status (as returned by waitpid, see the waitpid entry	689	Return the exit/wait status (as returned by waitpid, see the waitpid entry
…		…
551	watcher for all pids).	695	watcher for all pids).
552		696
553	=back	697	=back
554		698
555		699
		700	=head3 STAT WATCHERS - did the file attributes just change?
		701
		702	=over 4
		703
		704	=item $w = EV::stat $path, $interval, $callback
		705
		706	=item $w = EV::stat_ns $path, $interval, $callback
		707
		708	=item $w = $loop->stat ($path, $interval, $callback)
		709
		710	=item $w = $loop->stat_ns ($path, $interval, $callback)
		711
		712	Call the callback when a file status change has been detected on
		713	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		714	to "path does not exist" is a status change like any other.
		715
		716	The C<$interval> is a recommended polling interval for systems where
		717	OS-supported change notifications don't exist or are not supported. If
		718	you use C<0> then an unspecified default is used (which is highly
		719	recommended!), which is to be expected to be around five seconds usually.
		720
		721	This watcher type is not meant for massive numbers of stat watchers,
		722	as even with OS-supported change notifications, this can be
		723	resource-intensive.
		724
		725	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		726
		727	=item ... = $w->stat
		728
		729	This call is very similar to the perl C<stat> built-in: It stats (using
		730	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		731	well as EV's idea of the current stat values) to the values found.
		732
		733	In scalar context, a boolean is return indicating success or failure of
		734	the stat. In list context, the same 13-value list as with stat is returned
		735	(except that the blksize and blocks fields are not reliable).
		736
		737	In the case of an error, errno is set to C<ENOENT> (regardless of the
		738	actual error value) and the C<nlink> value is forced to zero (if the stat
		739	was successful then nlink is guaranteed to be non-zero).
		740
		741	See also the next two entries for more info.
		742
		743	=item ... = $w->attr
		744
		745	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		746	the values most recently detected by EV. See the next entry for more info.
		747
		748	=item ... = $w->prev
		749
		750	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		751	the previous set of values, before the change.
		752
		753	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		754	to the values found I<before> a change was detected, while C<< $w->attr >>
		755	returns the values found leading to the change detection. The difference (if any)
		756	between C<prev> and C<attr> is what triggered the callback.
		757
		758	If you did something to the filesystem object and do not want to trigger
		759	yet another change, you can call C<stat> to update EV's idea of what the
		760	current attributes are.
		761
		762	=item $w->set ($path, $interval)
		763
		764	Reconfigures the watcher, see the constructor above for details. Can be
		765	called at any time.
		766
		767	=item $current_path = $w->path
		768
		769	=item $old_path = $w->path ($new_path)
		770
		771	Returns the previously set path and optionally set a new one.
		772
		773	=item $current_interval = $w->interval
		774
		775	=item $old_interval = $w->interval ($new_interval)
		776
		777	Returns the previously set interval and optionally set a new one. Can be
		778	used to query the actual interval used.
		779
		780	=back
		781
		782
556	=head3 IDLE WATCHERS - when you've got nothing better to do...	783	=head3 IDLE WATCHERS - when you've got nothing better to do...
557		784
558	=over 4	785	=over 4
559		786
560	=item $w = EV::idle $callback	787	=item $w = EV::idle $callback
561		788
562	=item $w = EV::idle_ns $callback	789	=item $w = EV::idle_ns $callback
563		790
564	Call the callback when there are no pending io, timer/periodic, signal or	791	=item $w = $loop->idle ($callback)
565	child events, i.e. when the process is idle.	792
		793	=item $w = $loop->idle_ns ($callback)
		794
		795	Call the callback when there are no other pending watchers of the same or
		796	higher priority (excluding check, prepare and other idle watchers of the
		797	same or lower priority, of course). They are called idle watchers because
		798	when the watcher is the highest priority pending event in the process, the
		799	process is considered to be idle at that priority.
		800
		801	If you want a watcher that is only ever called when I<no> other events are
		802	outstanding you have to set the priority to C<EV::MINPRI>.
566		803
567	The process will not block as long as any idle watchers are active, and	804	The process will not block as long as any idle watchers are active, and
568	they will be called repeatedly until stopped.	805	they will be called repeatedly until stopped.
569		806
		807	For example, if you have idle watchers at priority C<0> and C<1>, and
		808	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		809	and the I/O watcher will always run when ready. Only when the idle watcher
		810	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		811	pending with the C<0>-priority idle watcher be invoked.
		812
570	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	813	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
571		814
572	=back	815	=back
573		816
574		817
…		…
577	=over 4	820	=over 4
578		821
579	=item $w = EV::prepare $callback	822	=item $w = EV::prepare $callback
580		823
581	=item $w = EV::prepare_ns $callback	824	=item $w = EV::prepare_ns $callback
		825
		826	=item $w = $loop->prepare ($callback)
		827
		828	=item $w = $loop->prepare_ns ($callback)
582		829
583	Call the callback just before the process would block. You can still	830	Call the callback just before the process would block. You can still
584	create/modify any watchers at this point.	831	create/modify any watchers at this point.
585		832
586	See the EV::check watcher, below, for explanations and an example.	833	See the EV::check watcher, below, for explanations and an example.
…		…
595	=over 4	842	=over 4
596		843
597	=item $w = EV::check $callback	844	=item $w = EV::check $callback
598		845
599	=item $w = EV::check_ns $callback	846	=item $w = EV::check_ns $callback
		847
		848	=item $w = $loop->check ($callback)
		849
		850	=item $w = $loop->check_ns ($callback)
600		851
601	Call the callback just after the process wakes up again (after it has	852	Call the callback just after the process wakes up again (after it has
602	gathered events), but before any other callbacks have been invoked.	853	gathered events), but before any other callbacks have been invoked.
603		854
604	This is used to integrate other event-based software into the EV	855	This is used to integrate other event-based software into the EV
…		…
614	or return;	865	or return;
615		866
616	# make the dispatcher handle any outstanding stuff	867	# make the dispatcher handle any outstanding stuff
617	... not shown	868	... not shown
618		869
619	# create an IO watcher for each and every socket	870	# create an I/O watcher for each and every socket
620	@snmp_watcher = (	871	@snmp_watcher = (
621	(map { EV::io $_, EV::READ, sub { } }	872	(map { EV::io $_, EV::READ, sub { } }
622	keys %{ $dispatcher->{_descriptors} }),	873	keys %{ $dispatcher->{_descriptors} }),
623		874
624	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	875	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
646		897
647	The C<check_ns> variant doesn't start (activate) the newly created watcher.	898	The C<check_ns> variant doesn't start (activate) the newly created watcher.
648		899
649	=back	900	=back
650		901
651	=head3 STAT WATCHERS - did the file stats just change?
652		902
653	=over 4	903	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
654		904
655	=item $w = EV::stat $path, $interval, $callback	905	Fork watchers are called when a C<fork ()> was detected. The invocation
		906	is done before the event loop blocks next and before C<check> watchers
		907	are being called, and only in the child after the fork.
656		908
657	=item $w = EV::stat_ns $path, $interval, $callback	909	=over 4
658		910
659	Call the callback when a file status change has been detected on	911	=item $w = EV::fork $callback
660	C<$path>. The C<$path> does not need to exist, changing from "path exists"
661	to "path does not exist" is a status change like any other.
662		912
663	The C<$interval> is a recommended polling interval for systems where	913	=item $w = EV::fork_ns $callback
664	OS-supported change notifications don't exist or are not supported. If
665	you use C<0> then an unspecified default is used (which is highly
666	recommended!), which is to be expected to be around five seconds usually.
667		914
668	This watcher type is not meant for massive numbers of stat watchers,	915	=item $w = $loop->fork ($callback)
669	as even with OS-supported change notifications, this can be
670	resource-intensive.
671		916
		917	=item $w = $loop->fork_ns ($callback)
		918
		919	Call the callback before the event loop is resumed in the child process
		920	after a fork.
		921
672	The C<stat_ns> variant doesn't start (activate) the newly created watcher.	922	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
673		923
674	=item $w->set ($path, $interval)
675
676	Reconfigures the watcher, see the constructor above for details. Can be
677	called at any time.
678
679	=item $current_path = $w->path
680
681	=item $old_path = $w->path ($new_path)
682
683	Returns the previously set path and optionally set a new one.
684
685	=item $current_interval = $w->interval
686
687	=item $old_interval = $w->interval ($new_interval)
688
689	Returns the previously set interval and optionally set a new one. Can be
690	used to query the actual interval used.
691
692	=back	924	=back
693		925
		926
		927	=head3 EMBED WATCHERS - when one backend isn't enough...
		928
		929	This is a rather advanced watcher type that lets you embed one event loop
		930	into another (currently only IO events are supported in the embedded
		931	loop, other types of watchers might be handled in a delayed or incorrect
		932	fashion and must not be used).
		933
		934	See the libev documentation at
		935	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		936	for more details.
		937
		938	In short, this watcher is most useful on BSD systems without working
		939	kqueue to still be able to handle a large number of sockets:
		940
		941	my $socket_loop;
		942
		943	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		944	if (
		945	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		946	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		947	) {
		948	# use kqueue for sockets
		949	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		950	}
		951
		952	# use the default loop otherwise
		953	$socket_loop \|\|= EV::default_loop;
		954
		955	=over 4
		956
		957	=item $w = EV::embed $otherloop, $callback
		958
		959	=item $w = EV::embed_ns $otherloop, $callback
		960
		961	=item $w = $loop->embed ($otherloop, $callback)
		962
		963	=item $w = $loop->embed_ns ($otherloop, $callback)
		964
		965	Call the callback when the embedded event loop (C<$otherloop>) has any
		966	I/O activity. The C<$callback> should alwas be specified as C<undef> in
		967	this version of EV, which means the embedded event loop will be managed
		968	automatically.
		969
		970	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		971
		972	=back
		973
		974	=head3 ASYNC WATCHERS - how to wake up another event loop
		975
		976	Async watchers are provided by EV, but have little use in perl directly, as perl
		977	neither supports threads nor direct access to signal handlers or other
		978	contexts where they could be of value.
		979
		980	It is, however, possible to use them from the XS level.
		981
		982	Please see the libev documentation for further details.
		983
		984
		985	=head1 PERL SIGNALS
		986
		987	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		988	with EV is as the same as any other C library: Perl-signals will only be
		989	handled when Perl runs, which means your signal handler might be invoked
		990	only the next time an event callback is invoked.
		991
		992	The solution is to use EV signal watchers (see C<EV::signal>), which will
		993	ensure proper operations with regards to other event watchers.
		994
		995	If you cannot do this for whatever reason, you can also force a watcher
		996	to be called on every event loop iteration by installing a C<EV::check>
		997	watcher:
		998
		999	my $async_check = EV::check sub { };
		1000
		1001	This ensures that perl gets into control for a short time to handle any
		1002	pending signals, and also ensures (slightly) slower overall operation.
694		1003
695	=head1 THREADS	1004	=head1 THREADS
696		1005
697	Threads are not supported by this module in any way. Perl pseudo-threads	1006	Threads are not supported by this module in any way. Perl pseudo-threads
698	is evil stuff and must die. As soon as Perl gains real threads I will work	1007	is evil stuff and must die. As soon as Perl gains real threads I will work
…		…
720	our $DIED = sub {	1029	our $DIED = sub {
721	warn "EV: error in callback (ignoring): $@";	1030	warn "EV: error in callback (ignoring): $@";
722	};	1031	};
723		1032
724	default_loop	1033	default_loop
725	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1034	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
726		1035
727	1;	1036	1;
728		1037
729	=head1 SEE ALSO	1038	=head1 SEE ALSO
730		1039
731	L<EV::DNS>.	1040	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1041	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1042	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP).
732		1043
733	=head1 AUTHOR	1044	=head1 AUTHOR
734		1045
735	Marc Lehmann <schmorp@schmorp.de>	1046	Marc Lehmann <schmorp@schmorp.de>
736	http://home.schmorp.de/	1047	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.54 by root, Tue Nov 27 07:27:10 2007 UTC vs. Revision 1.86 by root, Wed Apr 2 11:00:58 2008 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.54 by root, Tue Nov 27 07:27:10 2007 UTC vs.
Revision 1.86 by root, Wed Apr 2 11:00:58 2008 UTC