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

Comparing EV/EV.pm (file contents):
Revision 1.47 by root, Fri Nov 23 13:08:55 2007 UTC vs.
Revision 1.103 by root, Thu Oct 2 07:49:09 2008 UTC

…		…
2		2
3	EV - perl interface to libev, a high performance full-featured event loop	3	EV - perl interface to libev, a high performance full-featured event loop
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use EV;	7	use EV;
		8
		9	# TIMERS
		10
		11	my $w = EV::timer 2, 0, sub {
		12	warn "is called after 2s";
		13	};
		14
		15	my $w = EV::timer 2, 2, sub {
		16	warn "is called roughly every 2s (repeat = 2)";
		17	};
		18
		19	undef $w; # destroy event watcher again
		20
		21	my $w = EV::periodic 0, 60, 0, sub {
		22	warn "is called every minute, on the minute, exactly";
		23	};
		24
		25	# IO
		26
		27	my $w = EV::io *STDIN, EV::READ, sub {
		28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
		29	warn "stdin is readable, you entered: ", <STDIN>;
		30	};
		31
		32	# SIGNALS
		33
		34	my $w = EV::signal 'QUIT', sub {
		35	warn "sigquit received\n";
		36	};
		37
		38	# CHILD/PID STATUS CHANGES
8		39
9	# TIMERS	40	my $w = EV::child 666, 0, sub {
		41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
		43	};
10		44
11	my $w = EV::timer 2, 0, sub {	45	# STAT CHANGES
12	warn "is called after 2s";	46	my $w = EV::stat "/etc/passwd", 10, sub {
13	};
14
15	my $w = EV::timer 2, 2, sub {
16	warn "is called roughly every 2s (repeat = 2)";
17	};
18
19	undef $w; # destroy event watcher again
20
21	my $w = EV::periodic 0, 60, 0, sub {
22	warn "is called every minute, on the minute, exactly";
23	};
24
25	# IO
26
27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29	warn "stdin is readable, you entered: ", <STDIN>;
30	};
31
32	# SIGNALS
33
34	my $w = EV::signal 'QUIT', sub {
35	warn "sigquit received\n";
36	};
37
38	# CHILD/PID STATUS CHANGES
39
40	my $w = EV::child 666, sub {
41	my ($w, $revents) = @_;	47	my ($w, $revents) = @_;
42	my $status = $w->rstatus;	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://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more
		62	subtle details on watcher semantics or some discussion on the available
		63	backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just
		64	about in any case because it has much more detailed information.
		65
		66	This module is very fast and scalable. It is actually so fast that you
		67	can use it through the L<AnyEvent> module, stay portable to other event
		68	loops (if you don't rely on any watcher types not available through it)
		69	and still be faster than with any other event loop currently supported in
		70	Perl.
54		71
55	=cut	72	=cut
56		73
57	package EV;	74	package EV;
58		75
		76	no warnings;
59	use strict;	77	use strict;
60		78
61	BEGIN {	79	BEGIN {
62	our $VERSION = '1.2';	80	our $VERSION = '3.44';
63	use XSLoader;	81	use XSLoader;
64	XSLoader::load "EV", $VERSION;	82	XSLoader::load "EV", $VERSION;
65	}	83	}
66		84
67	@EV::Io::ISA =	85	@EV::IO::ISA =
68	@EV::Timer::ISA =	86	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	87	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	88	@EV::Signal::ISA =
		89	@EV::Child::ISA =
		90	@EV::Stat::ISA =
71	@EV::Idle::ISA =	91	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	92	@EV::Prepare::ISA =
73	@EV::Check::ISA =	93	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	94	@EV::Embed::ISA =
		95	@EV::Fork::ISA =
		96	@EV::Async::ISA =
		97	"EV::Watcher";
		98
		99	@EV::Loop::Default::ISA = "EV::Loop";
		100
		101	=head1 EVENT LOOPS
		102
		103	EV supports multiple event loops: There is a single "default event loop"
		104	that can handle everything including signals and child watchers, and any
		105	number of "dynamic event loops" that can use different backends (with
		106	various limitations), but no child and signal watchers.
		107
		108	You do not have to do anything to create the default event loop: When
		109	the module is loaded a suitable backend is selected on the premise of
		110	selecting a working backend (which for example rules out kqueue on most
		111	BSDs). Modules should, unless they have "special needs" always use the
		112	default loop as this is fastest (perl-wise), best supported by other
		113	modules (e.g. AnyEvent or Coro) and most portable event loop.
		114
		115	For specific programs you can create additional event loops dynamically.
		116
		117	If you want to take avdantage of kqueue (which often works properly for
		118	sockets only) even though the default loop doesn't enable it, you can
		119	I<embed> a kqueue loop into the default loop: running the default loop
		120	will then also service the kqueue loop to some extent. See the example in
		121	the section about embed watchers for an example on how to achieve that.
		122
		123	=over 4
		124
		125	=item $loop = new EV::loop [$flags]
		126
		127	Create a new event loop as per the specified flags. Please refer to the
		128	C<ev_loop_new ()> function description in the libev documentation
		129	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>)
		130	for more info.
		131
		132	The loop will automatically be destroyed when it is no longer referenced
		133	by any watcher and the loop object goes out of scope.
		134
		135	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		136	is recommended, as only the default event loop is protected by this
		137	module. If you I<are> embedding this loop in the default loop, this is not
		138	necessary, as C<EV::embed> automatically does the right thing on fork.
		139
		140	=item $loop->loop_fork
		141
		142	Must be called after a fork in the child, before entering or continuing
		143	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		144	this function automatically, at some performance loss (refer to the libev
		145	documentation).
		146
		147	=item $loop->loop_verify
		148
		149	Calls C<ev_verify> to make internal consistency checks (for debugging
		150	libev) and abort the program if any data structures were found to be
		151	corrupted.
		152
		153	=item $loop = EV::default_loop [$flags]
		154
		155	Return the default loop (which is a singleton object). Since this module
		156	already creates the default loop with default flags, specifying flags here
		157	will not have any effect unless you destroy the default loop first, which
		158	isn't supported. So in short: don't do it, and if you break it, you get to
		159	keep the pieces.
		160
		161	=back
		162
75		163
76	=head1 BASIC INTERFACE	164	=head1 BASIC INTERFACE
77		165
78	=over 4	166	=over 4
79		167
80	=item $EV::DIED	168	=item $EV::DIED
81		169
82	Must contain a reference to a function that is called when a callback	170	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	171	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	172	informative message and continues.
85		173
86	If this callback throws an exception it will be silently ignored.	174	If this callback throws an exception it will be silently ignored.
87		175
		176	=item $flags = EV::supported_backends
		177
		178	=item $flags = EV::recommended_backends
		179
		180	=item $flags = EV::embeddable_backends
		181
		182	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		183	instance of EV, the set of recommended backends (supposed to be good) for
		184	this platform and the set of embeddable backends (see EMBED WATCHERS).
		185
		186	=item EV::sleep $seconds
		187
		188	Block the process for the given number of (fractional) seconds.
		189
88	=item $time = EV::time	190	=item $time = EV::time
89		191
90	Returns the current time in (fractional) seconds since the epoch.	192	Returns the current time in (fractional) seconds since the epoch.
91		193
92	=item $time = EV::now	194	=item $time = EV::now
		195
		196	=item $time = $loop->now
93		197
94	Returns the time the last event loop iteration has been started. This	198	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	199	is the time that (relative) timers are based on, and refering to it is
96	usually faster then calling EV::time.	200	usually faster then calling EV::time.
97		201
98	=item $method = EV::method	202	=item $backend = EV::backend
		203
		204	=item $backend = $loop->backend
99		205
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	206	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
101	or EV::METHOD_EPOLL).	207	or EV::METHOD_EPOLL).
102		208
103	=item EV::loop [$flags]	209	=item EV::loop [$flags]
		210
		211	=item $loop->loop ([$flags])
104		212
105	Begin checking for events and calling callbacks. It returns when a	213	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	214	callback calls EV::unloop.
107		215
108	The $flags argument can be one of the following:	216	The $flags argument can be one of the following:
…		…
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	219	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	220	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
113		221
114	=item EV::unloop [$how]	222	=item EV::unloop [$how]
115		223
		224	=item $loop->unloop ([$how])
		225
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	226	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
117	innermost call to EV::loop return.	227	innermost call to EV::loop return.
118		228
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	229	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
120	fast as possible.	230	fast as possible.
121		231
		232	=item $count = EV::loop_count
		233
		234	=item $count = $loop->loop_count
		235
		236	Return the number of times the event loop has polled for new
		237	events. Sometiems useful as a generation counter.
		238
122	=item EV::once $fh_or_undef, $events, $timeout, $cb->($events)	239	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		240
		241	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
123		242
124	This function rolls together an I/O and a timer watcher for a single	243	This function rolls together an I/O and a timer watcher for a single
125	one-shot event without the need for managing a watcher object.	244	one-shot event without the need for managing a watcher object.
126		245
127	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>	246	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
…		…
133	If timeout is C<undef> or negative, then there will be no	252	If timeout is C<undef> or negative, then there will be no
134	timeout. Otherwise a EV::timer with this value will be started.	253	timeout. Otherwise a EV::timer with this value will be started.
135		254
136	When an error occurs or either the timeout or I/O watcher triggers, then	255	When an error occurs or either the timeout or I/O watcher triggers, then
137	the callback will be called with the received event set (in general	256	the callback will be called with the received event set (in general
138	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,	257	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
139	C<EV::WRITE> and C<EV::TIMEOUT>).	258	C<EV::WRITE> and C<EV::TIMEOUT>).
140		259
141	EV::once doesn't return anything: the watchers stay active till either	260	EV::once doesn't return anything: the watchers stay active till either
142	of them triggers, then they will be stopped and freed, and the callback	261	of them triggers, then they will be stopped and freed, and the callback
143	invoked.	262	invoked.
144		263
145	=back	264	=item EV::feed_fd_event ($fd, $revents)
146		265
147	=head2 WATCHER	266	=item $loop->feed_fd_event ($fd, $revents)
		267
		268	Feed an event on a file descriptor into EV. EV will react to this call as
		269	if the readyness notifications specified by C<$revents> (a combination of
		270	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		271
		272	=item EV::feed_signal_event ($signal)
		273
		274	Feed a signal event into EV. EV will react to this call as if the signal
		275	specified by C<$signal> had occured.
		276
		277	=item EV::set_io_collect_interval $time
		278
		279	=item $loop->set_io_collect_interval ($time)
		280
		281	=item EV::set_timeout_collect_interval $time
		282
		283	=item $loop->set_timeout_collect_interval ($time)
		284
		285	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		286	wait interval for timer events. See the libev documentation at
		287	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for
		288	a more detailed discussion.
		289
		290	=back
		291
		292
		293	=head1 WATCHER OBJECTS
148		294
149	A watcher is an object that gets created to record your interest in some	295	A watcher is an object that gets created to record your interest in some
150	event. For instance, if you want to wait for STDIN to become readable, you	296	event. For instance, if you want to wait for STDIN to become readable, you
151	would create an EV::io watcher for that:	297	would create an EV::io watcher for that:
152		298
153	my $watcher = EV::io *STDIN, EV::READ, sub {	299	my $watcher = EV::io *STDIN, EV::READ, sub {
154	my ($watcher, $revents) = @_;	300	my ($watcher, $revents) = @_;
155	warn "yeah, STDIN should not be readable without blocking!\n"	301	warn "yeah, STDIN should now be readable without blocking!\n"
156	};	302	};
157		303
158	All watchers can be active (waiting for events) or inactive (paused). Only	304	All watchers can be active (waiting for events) or inactive (paused). Only
159	active watchers will have their callbacks invoked. All callbacks will be	305	active watchers will have their callbacks invoked. All callbacks will be
160	called with at least two arguments: the watcher and a bitmask of received	306	called with at least two arguments: the watcher and a bitmask of received
161	events.	307	events.
162		308
163	Each watcher type has its associated bit in revents, so you can use the	309	Each watcher type has its associated bit in revents, so you can use the
164	same callback for multiple watchers. The event mask is named after the	310	same callback for multiple watchers. The event mask is named after the
165	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	311	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
166	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	312	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
167	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	313	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
168	uses EV::TIMEOUT).	314	uses EV::TIMEOUT).
169		315
170	In the rare case where one wants to create a watcher but not start it at	316	In the rare case where one wants to create a watcher but not start it at
171	the same time, each constructor has a variant with a trailing C<_ns> in	317	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
177		323
178	Also, all methods changing some aspect of a watcher (->set, ->priority,	324	Also, all methods changing some aspect of a watcher (->set, ->priority,
179	->fh and so on) automatically stop and start it again if it is active,	325	->fh and so on) automatically stop and start it again if it is active,
180	which means pending events get lost.	326	which means pending events get lost.
181		327
182	=head2 WATCHER TYPES	328	=head2 COMMON WATCHER METHODS
183		329
184	Now lets move to the existing watcher types and asociated methods.	330	This section lists methods common to all watchers.
185
186	The following methods are available for all watchers. Then followes a
187	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
188	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
189	any type-specific methods (if any).
190		331
191	=over 4	332	=over 4
192		333
193	=item $w->start	334	=item $w->start
194		335
…		…
198		339
199	=item $w->stop	340	=item $w->stop
200		341
201	Stop a watcher if it is active. Also clear any pending events (events that	342	Stop a watcher if it is active. Also clear any pending events (events that
202	have been received but that didn't yet result in a callback invocation),	343	have been received but that didn't yet result in a callback invocation),
203	regardless of wether the watcher was active or not.	344	regardless of whether the watcher was active or not.
204		345
205	=item $bool = $w->is_active	346	=item $bool = $w->is_active
206		347
207	Returns true if the watcher is active, false otherwise.	348	Returns true if the watcher is active, false otherwise.
208		349
…		…
233	watchers with higher priority will be invoked first. The valid range of	374	watchers with higher priority will be invoked first. The valid range of
234	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	375	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
235	-2). If the priority is outside this range it will automatically be	376	-2). If the priority is outside this range it will automatically be
236	normalised to the nearest valid priority.	377	normalised to the nearest valid priority.
237		378
238	The default priority of any newly-created weatcher is 0.	379	The default priority of any newly-created watcher is 0.
239		380
		381	Note that the priority semantics have not yet been fleshed out and are
		382	subject to almost certain change.
		383
240	=item $w->trigger ($revents)	384	=item $w->invoke ($revents)
241		385
242	Call the callback now with the given event mask.	386	Call the callback now with the given event mask.
243		387
		388	=item $w->feed_event ($revents)
		389
		390	Feed some events on this watcher into EV. EV will react to this call as if
		391	the watcher had received the given C<$revents> mask.
		392
		393	=item $revents = $w->clear_pending
		394
		395	If the watcher is pending, this function clears its pending status and
		396	returns its C<$revents> bitset (as if its callback was invoked). If the
		397	watcher isn't pending it does nothing and returns C<0>.
		398
		399	=item $previous_state = $w->keepalive ($bool)
		400
		401	Normally, C<EV::loop> will return when there are no active watchers
		402	(which is a "deadlock" because no progress can be made anymore). This is
		403	convinient because it allows you to start your watchers (and your jobs),
		404	call C<EV::loop> once and when it returns you know that all your jobs are
		405	finished (or they forgot to register some watchers for their task :).
		406
		407	Sometimes, however, this gets in your way, for example when the module
		408	that calls C<EV::loop> (usually the main program) is not the same module
		409	as a long-living watcher (for example a DNS client module written by
		410	somebody else even). Then you might want any outstanding requests to be
		411	handled, but you would not want to keep C<EV::loop> from returning just
		412	because you happen to have this long-running UDP port watcher.
		413
		414	In this case you can clear the keepalive status, which means that even
		415	though your watcher is active, it won't keep C<EV::loop> from returning.
		416
		417	The initial value for keepalive is true (enabled), and you cna change it
		418	any time.
		419
		420	Example: Register an I/O watcher for some UDP socket but do not keep the
		421	event loop from running just because of that watcher.
		422
		423	my $udp_socket = ...
		424	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		425	$udp_watcher->keepalive (0);
		426
		427	=item $loop = $w->loop
		428
		429	Return the loop that this watcher is attached to.
		430
		431	=back
		432
		433
		434	=head1 WATCHER TYPES
		435
		436	Each of the following subsections describes a single watcher type.
		437
		438	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		439
		440	=over 4
244		441
245	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	442	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
246		443
247	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	444	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
248		445
		446	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		447
		448	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		449
249	As long as the returned watcher object is alive, call the C<$callback>	450	As long as the returned watcher object is alive, call the C<$callback>
250	when the events specified in C<$eventmask>.	451	when at least one of events specified in C<$eventmask> occurs.
251		452
252	The $eventmask can be one or more of these constants ORed together:	453	The $eventmask can be one or more of these constants ORed together:
253		454
254	EV::READ wait until read() wouldn't block anymore	455	EV::READ wait until read() wouldn't block anymore
255	EV::WRITE wait until write() wouldn't block anymore	456	EV::WRITE wait until write() wouldn't block anymore
…		…
271		472
272	=item $old_eventmask = $w->events ($new_eventmask)	473	=item $old_eventmask = $w->events ($new_eventmask)
273		474
274	Returns the previously set event mask and optionally set a new one.	475	Returns the previously set event mask and optionally set a new one.
275		476
		477	=back
		478
		479
		480	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		481
		482	=over 4
276		483
277	=item $w = EV::timer $after, $repeat, $callback	484	=item $w = EV::timer $after, $repeat, $callback
278		485
279	=item $w = EV::timer_ns $after, $repeat, $callback	486	=item $w = EV::timer_ns $after, $repeat, $callback
280		487
281	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	488	=item $w = $loop->timer ($after, $repeat, $callback)
282	the timer will be restarted (with the $repeat value as $after) after the	489
283	callback returns.	490	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		491
		492	Calls the callback after C<$after> seconds (which may be fractional). If
		493	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		494	value as $after) after the callback returns.
284		495
285	This means that the callback would be called roughly after C<$after>	496	This means that the callback would be called roughly after C<$after>
286	seconds, and then every C<$repeat> seconds. The timer does his best not	497	seconds, and then every C<$repeat> seconds. The timer does his best not
287	to drift, but it will not invoke the timer more often then once per event	498	to drift, but it will not invoke the timer more often then once per event
288	loop iteration, and might drift in other cases. If that isn't acceptable,	499	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
294		505
295	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	506	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
296		507
297	=item $w->set ($after, $repeat)	508	=item $w->set ($after, $repeat)
298		509
299	Reconfigures the watcher, see the constructor above for details. Can be at	510	Reconfigures the watcher, see the constructor above for details. Can be called at
300	any time.	511	any time.
301		512
302	=item $w->again	513	=item $w->again
303		514
304	Similar to the C<start> method, but has special semantics for repeating timers:	515	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
315	This behaviour is useful when you have a timeout for some IO	526	This behaviour is useful when you have a timeout for some IO
316	operation. You create a timer object with the same value for C<$after> and	527	operation. You create a timer object with the same value for C<$after> and
317	C<$repeat>, and then, in the read/write watcher, run the C<again> method	528	C<$repeat>, and then, in the read/write watcher, run the C<again> method
318	on the timeout.	529	on the timeout.
319		530
		531	=back
		532
		533
		534	=head3 PERIODIC WATCHERS - to cron or not to cron?
		535
		536	=over 4
320		537
321	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	538	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
322		539
323	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	540	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		541
		542	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		543
		544	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
324		545
325	Similar to EV::timer, but is not based on relative timeouts but on	546	Similar to EV::timer, but is not based on relative timeouts but on
326	absolute times. Apart from creating "simple" timers that trigger "at" the	547	absolute times. Apart from creating "simple" timers that trigger "at" the
327	specified time, it can also be used for non-drifting absolute timers and	548	specified time, it can also be used for non-drifting absolute timers and
328	more complex, cron-like, setups that are not adversely affected by time	549	more complex, cron-like, setups that are not adversely affected by time
…		…
338	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	559	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
339	will not adjust when a time jump occurs, that is, if it is to be run	560	will not adjust when a time jump occurs, that is, if it is to be run
340	at January 1st 2011 then it will run when the system time reaches or	561	at January 1st 2011 then it will run when the system time reaches or
341	surpasses this time.	562	surpasses this time.
342		563
343	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	564	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
344		565
345	In this mode the watcher will always be scheduled to time out at the	566	In this mode the watcher will always be scheduled to time out at the
346	next C<$at + N * $interval> time (for some integer N) and then repeat,	567	next C<$at + N * $interval> time (for some integer N) and then repeat,
347	regardless of any time jumps.	568	regardless of any time jumps.
348		569
…		…
366	time the periodic watcher gets scheduled, the reschedule callback	587	time the periodic watcher gets scheduled, the reschedule callback
367	($reschedule_cb) will be called with the watcher as first, and the current	588	($reschedule_cb) will be called with the watcher as first, and the current
368	time as second argument.	589	time as second argument.
369		590
370	I<This callback MUST NOT stop or destroy this or any other periodic	591	I<This callback MUST NOT stop or destroy this or any other periodic
371	watcher, ever>. If you need to stop it, return 1e30 and stop it	592	watcher, ever, and MUST NOT call any event loop functions or methods>. If
372	afterwards.	593	you need to stop it, return 1e30 and stop it afterwards. You may create
		594	and start a C<EV::prepare> watcher for this task.
373		595
374	It must return the next time to trigger, based on the passed time value	596	It must return the next time to trigger, based on the passed time value
375	(that is, the lowest time value larger than to the second argument). It	597	(that is, the lowest time value larger than or equal to to the second
376	will usually be called just before the callback will be triggered, but	598	argument). It will usually be called just before the callback will be
377	might be called at other times, too.	599	triggered, but might be called at other times, too.
378		600
379	This can be used to create very complex timers, such as a timer that	601	This can be used to create very complex timers, such as a timer that
380	triggers on each midnight, local time (actually 24 hours after the last	602	triggers on each midnight, local time (actually 24 hours after the last
381	midnight, to keep the example simple. If you know a way to do it correctly	603	midnight, to keep the example simple. If you know a way to do it correctly
382	in about the same space (without requiring elaborate modules), drop me a	604	in about the same space (without requiring elaborate modules), drop me a
…		…
396		618
397	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	619	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
398		620
399	=item $w->set ($at, $interval, $reschedule_cb)	621	=item $w->set ($at, $interval, $reschedule_cb)
400		622
401	Reconfigures the watcher, see the constructor above for details. Can be at	623	Reconfigures the watcher, see the constructor above for details. Can be called at
402	any time.	624	any time.
403		625
404	=item $w->again	626	=item $w->again
405		627
406	Simply stops and starts the watcher again.	628	Simply stops and starts the watcher again.
407		629
		630	=item $time = $w->at
		631
		632	Return the time that the watcher is expected to trigger next.
		633
		634	=back
		635
		636
		637	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		638
		639	=over 4
408		640
409	=item $w = EV::signal $signal, $callback	641	=item $w = EV::signal $signal, $callback
410		642
411	=item $w = EV::signal_ns $signal, $callback	643	=item $w = EV::signal_ns $signal, $callback
412		644
413	Call the callback when $signal is received (the signal can be specified	645	Call the callback when $signal is received (the signal can be specified by
414	by number or by name, just as with kill or %SIG).	646	number or by name, just as with C<kill> or C<%SIG>).
415		647
416	EV will grab the signal for the process (the kernel only allows one	648	EV will grab the signal for the process (the kernel only allows one
417	component to receive a signal at a time) when you start a signal watcher,	649	component to receive a signal at a time) when you start a signal watcher,
418	and removes it again when you stop it. Perl does the same when you	650	and removes it again when you stop it. Perl does the same when you
419	add/remove callbacks to %SIG, so watch out.	651	add/remove callbacks to C<%SIG>, so watch out.
420		652
421	You can have as many signal watchers per signal as you want.	653	You can have as many signal watchers per signal as you want.
422		654
423	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	655	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
424		656
425	=item $w->set ($signal)	657	=item $w->set ($signal)
426		658
427	Reconfigures the watcher, see the constructor above for details. Can be at	659	Reconfigures the watcher, see the constructor above for details. Can be
428	any time.	660	called at any time.
429		661
430	=item $current_signum = $w->signal	662	=item $current_signum = $w->signal
431		663
432	=item $old_signum = $w->signal ($new_signal)	664	=item $old_signum = $w->signal ($new_signal)
433		665
434	Returns the previously set signal (always as a number not name) and	666	Returns the previously set signal (always as a number not name) and
435	optionally set a new one.	667	optionally set a new one.
436		668
		669	=back
437		670
		671
		672	=head3 CHILD WATCHERS - watch out for process status changes
		673
		674	=over 4
		675
438	=item $w = EV::child $pid, $callback	676	=item $w = EV::child $pid, $trace, $callback
439		677
440	=item $w = EV::child_ns $pid, $callback	678	=item $w = EV::child_ns $pid, $trace, $callback
		679
		680	=item $w = $loop->child ($pid, $trace, $callback)
		681
		682	=item $w = $loop->child_ns ($pid, $trace, $callback)
441		683
442	Call the callback when a status change for pid C<$pid> (or any pid	684	Call the callback when a status change for pid C<$pid> (or any pid
443	if C<$pid> is 0) has been received. More precisely: when the process	685	if C<$pid> is 0) has been received (a status change happens when the
		686	process terminates or is killed, or, when trace is true, additionally when
		687	it is stopped or continued). More precisely: when the process receives
444	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	688	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
445	changed/zombie children and call the callback.	689	changed/zombie children and call the callback.
446		690
447	You can access both status and pid by using the C<rstatus> and C<rpid>	691	It is valid (and fully supported) to install a child watcher after a child
448	methods on the watcher object.	692	has exited but before the event loop has started its next iteration (for
		693	example, first you C<fork>, then the new child process might exit, and
		694	only then do you install a child watcher in the parent for the new pid).
449		695
		696	You can access both exit (or tracing) status and pid by using the
		697	C<rstatus> and C<rpid> methods on the watcher object.
		698
450	You can have as many pid watchers per pid as you want.	699	You can have as many pid watchers per pid as you want, they will all be
		700	called.
451		701
452	The C<child_ns> variant doesn't start (activate) the newly created watcher.	702	The C<child_ns> variant doesn't start (activate) the newly created watcher.
453		703
454	=item $w->set ($pid)	704	=item $w->set ($pid, $trace)
455		705
456	Reconfigures the watcher, see the constructor above for details. Can be at	706	Reconfigures the watcher, see the constructor above for details. Can be called at
457	any time.	707	any time.
458		708
459	=item $current_pid = $w->pid	709	=item $current_pid = $w->pid
460
461	=item $old_pid = $w->pid ($new_pid)
462		710
463	Returns the previously set process id and optionally set a new one.	711	Returns the previously set process id and optionally set a new one.
464		712
465	=item $exit_status = $w->rstatus	713	=item $exit_status = $w->rstatus
466		714
…		…
470	=item $pid = $w->rpid	718	=item $pid = $w->rpid
471		719
472	Return the pid of the awaited child (useful when you have installed a	720	Return the pid of the awaited child (useful when you have installed a
473	watcher for all pids).	721	watcher for all pids).
474		722
		723	=back
		724
		725
		726	=head3 STAT WATCHERS - did the file attributes just change?
		727
		728	=over 4
		729
		730	=item $w = EV::stat $path, $interval, $callback
		731
		732	=item $w = EV::stat_ns $path, $interval, $callback
		733
		734	=item $w = $loop->stat ($path, $interval, $callback)
		735
		736	=item $w = $loop->stat_ns ($path, $interval, $callback)
		737
		738	Call the callback when a file status change has been detected on
		739	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		740	to "path does not exist" is a status change like any other.
		741
		742	The C<$interval> is a recommended polling interval for systems where
		743	OS-supported change notifications don't exist or are not supported. If
		744	you use C<0> then an unspecified default is used (which is highly
		745	recommended!), which is to be expected to be around five seconds usually.
		746
		747	This watcher type is not meant for massive numbers of stat watchers,
		748	as even with OS-supported change notifications, this can be
		749	resource-intensive.
		750
		751	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		752
		753	=item ... = $w->stat
		754
		755	This call is very similar to the perl C<stat> built-in: It stats (using
		756	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		757	well as EV's idea of the current stat values) to the values found.
		758
		759	In scalar context, a boolean is return indicating success or failure of
		760	the stat. In list context, the same 13-value list as with stat is returned
		761	(except that the blksize and blocks fields are not reliable).
		762
		763	In the case of an error, errno is set to C<ENOENT> (regardless of the
		764	actual error value) and the C<nlink> value is forced to zero (if the stat
		765	was successful then nlink is guaranteed to be non-zero).
		766
		767	See also the next two entries for more info.
		768
		769	=item ... = $w->attr
		770
		771	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		772	the values most recently detected by EV. See the next entry for more info.
		773
		774	=item ... = $w->prev
		775
		776	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		777	the previous set of values, before the change.
		778
		779	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		780	to the values found I<before> a change was detected, while C<< $w->attr >>
		781	returns the values found leading to the change detection. The difference (if any)
		782	between C<prev> and C<attr> is what triggered the callback.
		783
		784	If you did something to the filesystem object and do not want to trigger
		785	yet another change, you can call C<stat> to update EV's idea of what the
		786	current attributes are.
		787
		788	=item $w->set ($path, $interval)
		789
		790	Reconfigures the watcher, see the constructor above for details. Can be
		791	called at any time.
		792
		793	=item $current_path = $w->path
		794
		795	=item $old_path = $w->path ($new_path)
		796
		797	Returns the previously set path and optionally set a new one.
		798
		799	=item $current_interval = $w->interval
		800
		801	=item $old_interval = $w->interval ($new_interval)
		802
		803	Returns the previously set interval and optionally set a new one. Can be
		804	used to query the actual interval used.
		805
		806	=back
		807
		808
		809	=head3 IDLE WATCHERS - when you've got nothing better to do...
		810
		811	=over 4
475		812
476	=item $w = EV::idle $callback	813	=item $w = EV::idle $callback
477		814
478	=item $w = EV::idle_ns $callback	815	=item $w = EV::idle_ns $callback
479		816
480	Call the callback when there are no pending io, timer/periodic, signal or	817	=item $w = $loop->idle ($callback)
481	child events, i.e. when the process is idle.	818
		819	=item $w = $loop->idle_ns ($callback)
		820
		821	Call the callback when there are no other pending watchers of the same or
		822	higher priority (excluding check, prepare and other idle watchers of the
		823	same or lower priority, of course). They are called idle watchers because
		824	when the watcher is the highest priority pending event in the process, the
		825	process is considered to be idle at that priority.
		826
		827	If you want a watcher that is only ever called when I<no> other events are
		828	outstanding you have to set the priority to C<EV::MINPRI>.
482		829
483	The process will not block as long as any idle watchers are active, and	830	The process will not block as long as any idle watchers are active, and
484	they will be called repeatedly until stopped.	831	they will be called repeatedly until stopped.
485		832
		833	For example, if you have idle watchers at priority C<0> and C<1>, and
		834	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		835	and the I/O watcher will always run when ready. Only when the idle watcher
		836	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		837	pending with the C<0>-priority idle watcher be invoked.
		838
486	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	839	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
487		840
		841	=back
		842
		843
		844	=head3 PREPARE WATCHERS - customise your event loop!
		845
		846	=over 4
488		847
489	=item $w = EV::prepare $callback	848	=item $w = EV::prepare $callback
490		849
491	=item $w = EV::prepare_ns $callback	850	=item $w = EV::prepare_ns $callback
		851
		852	=item $w = $loop->prepare ($callback)
		853
		854	=item $w = $loop->prepare_ns ($callback)
492		855
493	Call the callback just before the process would block. You can still	856	Call the callback just before the process would block. You can still
494	create/modify any watchers at this point.	857	create/modify any watchers at this point.
495		858
496	See the EV::check watcher, below, for explanations and an example.	859	See the EV::check watcher, below, for explanations and an example.
497		860
498	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	861	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
499		862
		863	=back
		864
		865
		866	=head3 CHECK WATCHERS - customise your event loop even more!
		867
		868	=over 4
500		869
501	=item $w = EV::check $callback	870	=item $w = EV::check $callback
502		871
503	=item $w = EV::check_ns $callback	872	=item $w = EV::check_ns $callback
		873
		874	=item $w = $loop->check ($callback)
		875
		876	=item $w = $loop->check_ns ($callback)
504		877
505	Call the callback just after the process wakes up again (after it has	878	Call the callback just after the process wakes up again (after it has
506	gathered events), but before any other callbacks have been invoked.	879	gathered events), but before any other callbacks have been invoked.
507		880
508	This is used to integrate other event-based software into the EV	881	This is used to integrate other event-based software into the EV
…		…
518	or return;	891	or return;
519		892
520	# make the dispatcher handle any outstanding stuff	893	# make the dispatcher handle any outstanding stuff
521	... not shown	894	... not shown
522		895
523	# create an IO watcher for each and every socket	896	# create an I/O watcher for each and every socket
524	@snmp_watcher = (	897	@snmp_watcher = (
525	(map { EV::io $_, EV::READ, sub { } }	898	(map { EV::io $_, EV::READ, sub { } }
526	keys %{ $dispatcher->{_descriptors} }),	899	keys %{ $dispatcher->{_descriptors} }),
527		900
528	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	901	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
549	first).	922	first).
550		923
551	The C<check_ns> variant doesn't start (activate) the newly created watcher.	924	The C<check_ns> variant doesn't start (activate) the newly created watcher.
552		925
553	=back	926	=back
		927
		928
		929	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		930
		931	Fork watchers are called when a C<fork ()> was detected. The invocation
		932	is done before the event loop blocks next and before C<check> watchers
		933	are being called, and only in the child after the fork.
		934
		935	=over 4
		936
		937	=item $w = EV::fork $callback
		938
		939	=item $w = EV::fork_ns $callback
		940
		941	=item $w = $loop->fork ($callback)
		942
		943	=item $w = $loop->fork_ns ($callback)
		944
		945	Call the callback before the event loop is resumed in the child process
		946	after a fork.
		947
		948	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		949
		950	=back
		951
		952
		953	=head3 EMBED WATCHERS - when one backend isn't enough...
		954
		955	This is a rather advanced watcher type that lets you embed one event loop
		956	into another (currently only IO events are supported in the embedded
		957	loop, other types of watchers might be handled in a delayed or incorrect
		958	fashion and must not be used).
		959
		960	See the libev documentation at
		961	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		962	for more details.
		963
		964	In short, this watcher is most useful on BSD systems without working
		965	kqueue to still be able to handle a large number of sockets:
		966
		967	my $socket_loop;
		968
		969	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		970	if (
		971	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		972	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		973	) {
		974	# use kqueue for sockets
		975	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		976	}
		977
		978	# use the default loop otherwise
		979	$socket_loop \|\|= EV::default_loop;
		980
		981	=over 4
		982
		983	=item $w = EV::embed $otherloop[, $callback]
		984
		985	=item $w = EV::embed_ns $otherloop[, $callback]
		986
		987	=item $w = $loop->embed ($otherloop[, $callback])
		988
		989	=item $w = $loop->embed_ns ($otherloop[, $callback])
		990
		991	Call the callback when the embedded event loop (C<$otherloop>) has any
		992	I/O activity. The C<$callback> is optional: if it is missing, then the
		993	embedded event loop will be managed automatically (which is recommended),
		994	otherwise you have to invoke C<sweep> yourself.
		995
		996	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		997
		998	=back
		999
		1000	=head3 ASYNC WATCHERS - how to wake up another event loop
		1001
		1002	Async watchers are provided by EV, but have little use in perl directly, as perl
		1003	neither supports threads nor direct access to signal handlers or other
		1004	contexts where they could be of value.
		1005
		1006	It is, however, possible to use them from the XS level.
		1007
		1008	Please see the libev documentation for further details.
		1009
		1010	=over 4
		1011
		1012	=item $w = EV::async $callback
		1013
		1014	=item $w = EV::async_ns $callback
		1015
		1016	=item $w->send
		1017
		1018	=item $bool = $w->async_pending
		1019
		1020	=back
		1021
		1022
		1023	=head1 PERL SIGNALS
		1024
		1025	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1026	with EV is as the same as any other C library: Perl-signals will only be
		1027	handled when Perl runs, which means your signal handler might be invoked
		1028	only the next time an event callback is invoked.
		1029
		1030	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1031	ensure proper operations with regards to other event watchers.
		1032
		1033	If you cannot do this for whatever reason, you can also force a watcher
		1034	to be called on every event loop iteration by installing a C<EV::check>
		1035	watcher:
		1036
		1037	my $async_check = EV::check sub { };
		1038
		1039	This ensures that perl gets into control for a short time to handle any
		1040	pending signals, and also ensures (slightly) slower overall operation.
554		1041
555	=head1 THREADS	1042	=head1 THREADS
556		1043
557	Threads are not supported by this module in any way. Perl pseudo-threads	1044	Threads are not supported by this module in any way. Perl pseudo-threads
558	is evil stuff and must die. As soon as Perl gains real threads I will work	1045	is evil stuff and must die. As soon as Perl gains real threads I will work
…		…
580	our $DIED = sub {	1067	our $DIED = sub {
581	warn "EV: error in callback (ignoring): $@";	1068	warn "EV: error in callback (ignoring): $@";
582	};	1069	};
583		1070
584	default_loop	1071	default_loop
585	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1072	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
586		1073
587	1;	1074	1;
588		1075
589	=head1 SEE ALSO	1076	=head1 SEE ALSO
590		1077
591	L<EV::DNS>.	1078	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1079	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1080	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1081	event-loop agnostic and portable event driven programming.
592		1082
593	=head1 AUTHOR	1083	=head1 AUTHOR
594		1084
595	Marc Lehmann <schmorp@schmorp.de>	1085	Marc Lehmann <schmorp@schmorp.de>
596	http://home.schmorp.de/	1086	http://home.schmorp.de/
597		1087
598	=cut	1088	=cut
599		1089

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Comparing EV/EV.pm (file contents): Revision 1.47 by root, Fri Nov 23 13:08:55 2007 UTC vs. Revision 1.103 by root, Thu Oct 2 07:49:09 2008 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.47 by root, Fri Nov 23 13:08:55 2007 UTC vs.
Revision 1.103 by root, Thu Oct 2 07:49:09 2008 UTC