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

Comparing EV/EV.pm (file contents):
Revision 1.44 by root, Thu Nov 22 04:52:23 2007 UTC vs.
Revision 1.83 by root, Mon Jan 28 12:24:05 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	};
		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";
43	};	49	};
44		50
45	# MAINLOOP	51	# MAINLOOP
46	EV::loop; # loop until EV::unloop 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 = '1.2';	73	our $VERSION = '3.0';
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 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
75		137
76	=head1 BASIC INTERFACE	138	=head1 BASIC INTERFACE
77		139
78	=over 4	140	=over 4
79		141
80	=item $EV::DIED	142	=item $EV::DIED
81		143
82	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
83	throws an exception (with $@ containing thr error). The default prints an	145	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	146	informative message and continues.
85		147
86	If this callback throws an exception it will be silently ignored.	148	If this callback throws an exception it will be silently ignored.
87		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
88	=item $time = EV::time	164	=item $time = EV::time
89		165
90	Returns the current time in (fractional) seconds since the epoch.	166	Returns the current time in (fractional) seconds since the epoch.
91		167
92	=item $time = EV::now	168	=item $time = EV::now
		169
		170	=item $time = $loop->now
93		171
94	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
95	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
96	usually faster then calling EV::time.	174	usually faster then calling EV::time.
97		175
98	=item $method = EV::method	176	=item $backend = EV::backend
		177
		178	=item $backend = $loop->backend
99		179
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	180	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	181	or EV::METHOD_EPOLL).
102		182
103	=item EV::loop [$flags]	183	=item EV::loop [$flags]
		184
		185	=item $loop->loop ([$flags])
104		186
105	Begin checking for events and calling callbacks. It returns when a	187	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	188	callback calls EV::unloop.
107		189
108	The $flags argument can be one of the following:	190	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	193	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	194	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		195
114	=item EV::unloop [$how]	196	=item EV::unloop [$how]
115		197
		198	=item $loop->unloop ([$how])
		199
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	200	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	201	innermost call to EV::loop return.
118		202
119	When called with an argument of EV::UNLOOP_ALL, 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
120	fast as possible.	204	fast as possible.
121		205
122	=back	206	=item $count = EV::loop_count
123		207
124	=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
125		268
126	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
127	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
128	would create an EV::io watcher for that:	271	would create an EV::io watcher for that:
129		272
130	my $watcher = EV::io *STDIN, EV::READ, sub {	273	my $watcher = EV::io *STDIN, EV::READ, sub {
131	my ($watcher, $revents) = @_;	274	my ($watcher, $revents) = @_;
132	warn "yeah, STDIN should not be readable without blocking!\n"	275	warn "yeah, STDIN should now be readable without blocking!\n"
133	};	276	};
134		277
135	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
136	active watchers will have their callbacks invoked. All callbacks will be	279	active watchers will have their callbacks invoked. All callbacks will be
137	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
138	events.	281	events.
139		282
140	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
141	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
142	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,
143	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
144	(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
145	uses EV::TIMEOUT).	288	uses EV::TIMEOUT).
146		289
147	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
148	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
…		…
154		297
155	Also, all methods changing some aspect of a watcher (->set, ->priority,	298	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,	299	->fh and so on) automatically stop and start it again if it is active,
157	which means pending events get lost.	300	which means pending events get lost.
158		301
159	=head2 WATCHER TYPES	302	=head2 COMMON WATCHER METHODS
160		303
161	Now lets move to the existing watcher types and asociated methods.	304	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		305
168	=over 4	306	=over 4
169		307
170	=item $w->start	308	=item $w->start
171		309
…		…
175		313
176	=item $w->stop	314	=item $w->stop
177		315
178	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
179	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),
180	regardless of wether the watcher was active or not.	318	regardless of whether the watcher was active or not.
181		319
182	=item $bool = $w->is_active	320	=item $bool = $w->is_active
183		321
184	Returns true if the watcher is active, false otherwise.	322	Returns true if the watcher is active, false otherwise.
185		323
…		…
210	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
211	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	349	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
212	-2). If the priority is outside this range it will automatically be	350	-2). If the priority is outside this range it will automatically be
213	normalised to the nearest valid priority.	351	normalised to the nearest valid priority.
214		352
215	The default priority of any newly-created weatcher is 0.	353	The default priority of any newly-created watcher is 0.
216		354
		355	Note that the priority semantics have not yet been fleshed out and are
		356	subject to almost certain change.
		357
217	=item $w->trigger ($revents)	358	=item $w->invoke ($revents)
218		359
219	Call the callback now with the given event mask.	360	Call the callback now with the given event mask.
220		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
221		415
222	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	416	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
223		417
224	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	418	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
225		419
		420	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		421
		422	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		423
226	As long as the returned watcher object is alive, call the C<$callback>	424	As long as the returned watcher object is alive, call the C<$callback>
227	when the events specified in C<$eventmask>.	425	when at least one of events specified in C<$eventmask> occurs.
228		426
229	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:
230		428
231	EV::READ wait until read() wouldn't block anymore	429	EV::READ wait until read() wouldn't block anymore
232	EV::WRITE wait until write() wouldn't block anymore	430	EV::WRITE wait until write() wouldn't block anymore
…		…
248		446
249	=item $old_eventmask = $w->events ($new_eventmask)	447	=item $old_eventmask = $w->events ($new_eventmask)
250		448
251	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.
252		450
		451	=back
		452
		453
		454	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		455
		456	=over 4
253		457
254	=item $w = EV::timer $after, $repeat, $callback	458	=item $w = EV::timer $after, $repeat, $callback
255		459
256	=item $w = EV::timer_ns $after, $repeat, $callback	460	=item $w = EV::timer_ns $after, $repeat, $callback
257		461
258	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	462	=item $w = $loop->timer ($after, $repeat, $callback)
259	the timer will be restarted (with the $repeat value as $after) after the	463
260	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 $after) after the callback returns.
261		469
262	This means that the callback would be called roughly after C<$after>	470	This means that the callback would be called roughly after C<$after>
263	seconds, and then every C<$repeat> seconds. The timer does his best not	471	seconds, and then every C<$repeat> seconds. The timer does his best not
264	to drift, but it will not invoke the timer more often then once per event	472	to drift, but it will not invoke the timer more often then once per event
265	loop iteration, and might drift in other cases. If that isn't acceptable,	473	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
271		479
272	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.
273		481
274	=item $w->set ($after, $repeat)	482	=item $w->set ($after, $repeat)
275		483
276	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
277	any time.	485	any time.
278		486
279	=item $w->again	487	=item $w->again
280		488
281	Similar to the C<start> method, but has special semantics for repeating timers:	489	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
292	This behaviour is useful when you have a timeout for some IO	500	This behaviour is useful when you have a timeout for some IO
293	operation. You create a timer object with the same value for C<$after> and	501	operation. You create a timer object with the same value for C<$after> and
294	C<$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
295	on the timeout.	503	on the timeout.
296		504
		505	=back
		506
		507
		508	=head3 PERIODIC WATCHERS - to cron or not to cron?
		509
		510	=over 4
297		511
298	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	512	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
299		513
300	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	514	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		515
		516	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		517
		518	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
301		519
302	Similar to EV::timer, but is not based on relative timeouts but on	520	Similar to EV::timer, but is not based on relative timeouts but on
303	absolute times. Apart from creating "simple" timers that trigger "at" the	521	absolute times. Apart from creating "simple" timers that trigger "at" the
304	specified time, it can also be used for non-drifting absolute timers and	522	specified time, it can also be used for non-drifting absolute timers and
305	more complex, cron-like, setups that are not adversely affected by time	523	more complex, cron-like, setups that are not adversely affected by time
…		…
373		591
374	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.
375		593
376	=item $w->set ($at, $interval, $reschedule_cb)	594	=item $w->set ($at, $interval, $reschedule_cb)
377		595
378	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
379	any time.	597	any time.
380		598
381	=item $w->again	599	=item $w->again
382		600
383	Simply stops and starts the watcher again.	601	Simply stops and starts the watcher again.
384		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
385		613
386	=item $w = EV::signal $signal, $callback	614	=item $w = EV::signal $signal, $callback
387		615
388	=item $w = EV::signal_ns $signal, $callback	616	=item $w = EV::signal_ns $signal, $callback
389		617
390	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
391	by number or by name, just as with kill or %SIG).	619	number or by name, just as with C<kill> or C<%SIG>).
392		620
393	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
394	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,
395	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
396	add/remove callbacks to %SIG, so watch out.	624	add/remove callbacks to C<%SIG>, so watch out.
397		625
398	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.
399		627
400	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.
401		629
402	=item $w->set ($signal)	630	=item $w->set ($signal)
403		631
404	Reconfigures the watcher, see the constructor above for details. Can be at	632	Reconfigures the watcher, see the constructor above for details. Can be
405	any time.	633	called at any time.
406		634
407	=item $current_signum = $w->signal	635	=item $current_signum = $w->signal
408		636
409	=item $old_signum = $w->signal ($new_signal)	637	=item $old_signum = $w->signal ($new_signal)
410		638
411	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
412	optionally set a new one.	640	optionally set a new one.
413		641
		642	=back
414		643
		644
		645	=head3 CHILD WATCHERS - watch out for process status changes
		646
		647	=over 4
		648
415	=item $w = EV::child $pid, $callback	649	=item $w = EV::child $pid, $trace, $callback
416		650
417	=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, $callback)
418		656
419	Call the callback when a status change for pid C<$pid> (or any pid	657	Call the callback when a status change for pid C<$pid> (or any pid
420	if C<$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
421	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
422	changed/zombie children and call the callback.	662	changed/zombie children and call the callback.
423		663
424	You can access both status and pid by using the C<rstatus> and C<rpid>	664	It is valid (and fully supported) to install a child watcher after a child
425	methods on the watcher object.	665	has exited but before the event loop has started its next iteration (for
		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).
426		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
427	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.
428		674
429	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.
430		676
431	=item $w->set ($pid)	677	=item $w->set ($pid, $trace)
432		678
433	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
434	any time.	680	any time.
435		681
436	=item $current_pid = $w->pid	682	=item $current_pid = $w->pid
437
438	=item $old_pid = $w->pid ($new_pid)
439		683
440	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.
441		685
442	=item $exit_status = $w->rstatus	686	=item $exit_status = $w->rstatus
443		687
…		…
447	=item $pid = $w->rpid	691	=item $pid = $w->rpid
448		692
449	Return the pid of the awaited child (useful when you have installed a	693	Return the pid of the awaited child (useful when you have installed a
450	watcher for all pids).	694	watcher for all pids).
451		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
452		785
453	=item $w = EV::idle $callback	786	=item $w = EV::idle $callback
454		787
455	=item $w = EV::idle_ns $callback	788	=item $w = EV::idle_ns $callback
456		789
457	Call the callback when there are no pending io, timer/periodic, signal or	790	=item $w = $loop->idle ($callback)
458	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>.
459		802
460	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
461	they will be called repeatedly until stopped.	804	they will be called repeatedly until stopped.
462		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
463	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.
464		813
		814	=back
		815
		816
		817	=head3 PREPARE WATCHERS - customise your event loop!
		818
		819	=over 4
465		820
466	=item $w = EV::prepare $callback	821	=item $w = EV::prepare $callback
467		822
468	=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)
469		828
470	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
471	create/modify any watchers at this point.	830	create/modify any watchers at this point.
472		831
473	See the EV::check watcher, below, for explanations and an example.	832	See the EV::check watcher, below, for explanations and an example.
474		833
475	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.
476		835
		836	=back
		837
		838
		839	=head3 CHECK WATCHERS - customise your event loop even more!
		840
		841	=over 4
477		842
478	=item $w = EV::check $callback	843	=item $w = EV::check $callback
479		844
480	=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)
481		850
482	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
483	gathered events), but before any other callbacks have been invoked.	852	gathered events), but before any other callbacks have been invoked.
484		853
485	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
…		…
493	# do nothing unless active	862	# do nothing unless active
494	$dispatcher->{_event_queue_h}	863	$dispatcher->{_event_queue_h}
495	or return;	864	or return;
496		865
497	# make the dispatcher handle any outstanding stuff	866	# make the dispatcher handle any outstanding stuff
		867	... not shown
498		868
499	# create an IO watcher for each and every socket	869	# create an I/O watcher for each and every socket
500	@snmp_watcher = (	870	@snmp_watcher = (
501	(map { EV::io $_, EV::READ, sub { } }	871	(map { EV::io $_, EV::READ, sub { } }
502	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 { },
503	);	877	);
504
505	# if there are any timeouts, also create a timer
506	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
507	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
508	};	878	};
509		879
510	The callbacks are irrelevant, the only purpose of those watchers is	880	The callbacks are irrelevant (and are not even being called), the
511	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
512	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
513	clean up:	883	corresponding EV::check watcher will then clean up:
514		884
515	our $snmp_check = EV::check sub {	885	our $snmp_check = EV::check sub {
516	# destroy all watchers	886	# destroy all watchers
517	@snmp_watcher = ();	887	@snmp_watcher = ();
518		888
519	# make the dispatcher handle any new stuff	889	# make the dispatcher handle any new stuff
		890	... not shown
520	};	891	};
521		892
522	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
523	are destroyed before this cna happen (remember EV::check gets called	894	are destroyed before this cna happen (remember EV::check gets called
524	first).	895	first).
525		896
526	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.
527		898
528	=back	899	=back
529		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
530	=head1 THREADS	993	=head1 THREADS
531		994
532	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
533	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.
534		1015
535	=cut	1016	=cut
536		1017
537	our $DIED = sub {	1018	our $DIED = sub {
538	warn "EV: error in callback (ignoring): $@";	1019	warn "EV: error in callback (ignoring): $@";
539	};	1020	};
540		1021
541	default_loop	1022	default_loop
542	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1023	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
543		1024
544	1;	1025	1;
545		1026
546	=head1 SEE ALSO	1027	=head1 SEE ALSO
547		1028
548	L<EV::DNS>.	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).
549		1032
550	=head1 AUTHOR	1033	=head1 AUTHOR
551		1034
552	Marc Lehmann <schmorp@schmorp.de>	1035	Marc Lehmann <schmorp@schmorp.de>
553	http://home.schmorp.de/	1036	http://home.schmorp.de/

Diff Legend

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

Comparing EV/EV.pm (file contents): Revision 1.44 by root, Thu Nov 22 04:52:23 2007 UTC vs. Revision 1.83 by root, Mon Jan 28 12:24:05 2008 UTC

Diff Legend

Comparing EV/EV.pm (file contents):
Revision 1.44 by root, Thu Nov 22 04:52:23 2007 UTC vs.
Revision 1.83 by root, Mon Jan 28 12:24:05 2008 UTC