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

Comparing EV/EV.pm (file contents):
Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs.
Revision 1.126 by root, Tue Mar 16 17:11:48 2010 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 $w = EV::stat "/etc/passwd", 10, sub {
		47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
13	};	49	};
14		50
15	my $w = EV::timer 2, 1, sub {
16	warn "is called roughly every 2s (repeat = 1)";
17	};
18
19	undef $w; # destroy event watcher again
20
21	my $w = EV::periodic 0, 60, 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 get the watcher object 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	my $w = EV::signal 3, sub {
39	warn "sigquit received (this is GNU/Linux, right?)\n";
40	};
41
42	# CHILD/PID STATUS CHANGES
43
44	my $w = EV::child 666, sub {
45	my ($w, $revents, $status) = @_;
46	};
47
48	# MAINLOOP	51	# MAINLOOP
49	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
50	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
51	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
52		55
53	=head1 DESCRIPTION	56	=head1 DESCRIPTION
54		57
55	This module provides an interface to libev	58	This module provides an interface to libev
56	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of
		61	libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
		62	F<perldoc EV::libev>) for more subtle details on watcher semantics or some
		63	discussion on the available backends, or how to force a specific backend
		64	with C<LIBEV_FLAGS>, or just about in any case because it has much more
		65	detailed information.
		66
		67	This module is very fast and scalable. It is actually so fast that you
		68	can use it through the L<AnyEvent> module, stay portable to other event
		69	loops (if you don't rely on any watcher types not available through it)
		70	and still be faster than with any other event loop currently supported in
		71	Perl.
		72
		73	=head2 MODULE EXPORTS
		74
		75	This module does not export any symbols.
57		76
58	=cut	77	=cut
59		78
60	package EV;	79	package EV;
61		80
62	use strict;	81	use common::sense;
63		82
64	BEGIN {	83	BEGIN {
65	our $VERSION = '0.1';	84	our $VERSION = '4.00';
66	use XSLoader;	85	use XSLoader;
67	XSLoader::load "EV", $VERSION;	86	XSLoader::load "EV", $VERSION;
68	}	87	}
69		88
70	@EV::Io::ISA =	89	@EV::IO::ISA =
71	@EV::Timer::ISA =	90	@EV::Timer::ISA =
72	@EV::Periodic::ISA =	91	@EV::Periodic::ISA =
73	@EV::Signal::ISA =	92	@EV::Signal::ISA =
		93	@EV::Child::ISA =
		94	@EV::Stat::ISA =
74	@EV::Idle::ISA =	95	@EV::Idle::ISA =
75	@EV::Prepare::ISA =	96	@EV::Prepare::ISA =
76	@EV::Check::ISA =	97	@EV::Check::ISA =
77	@EV::Child::ISA = "EV::Watcher";	98	@EV::Embed::ISA =
		99	@EV::Fork::ISA =
		100	@EV::Async::ISA =
		101	"EV::Watcher";
		102
		103	@EV::Loop::Default::ISA = "EV::Loop";
		104
		105	=head1 EVENT LOOPS
		106
		107	EV supports multiple event loops: There is a single "default event loop"
		108	that can handle everything including signals and child watchers, and any
		109	number of "dynamic event loops" that can use different backends (with
		110	various limitations), but no child and signal watchers.
		111
		112	You do not have to do anything to create the default event loop: When
		113	the module is loaded a suitable backend is selected on the premise of
		114	selecting a working backend (which for example rules out kqueue on most
		115	BSDs). Modules should, unless they have "special needs" always use the
		116	default loop as this is fastest (perl-wise), best supported by other
		117	modules (e.g. AnyEvent or Coro) and most portable event loop.
		118
		119	For specific programs you can create additional event loops dynamically.
		120
		121	If you want to take advantage of kqueue (which often works properly for
		122	sockets only) even though the default loop doesn't enable it, you can
		123	I<embed> a kqueue loop into the default loop: running the default loop
		124	will then also service the kqueue loop to some extent. See the example in
		125	the section about embed watchers for an example on how to achieve that.
		126
		127	=over 4
		128
		129	=item $loop = new EV::Loop [$flags]
		130
		131	Create a new event loop as per the specified flags. Please refer to
		132	the C<ev_loop_new ()> function description in the libev documentation
		133	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
		134	or locally-installed as F<EV::libev> manpage) for more info.
		135
		136	The loop will automatically be destroyed when it is no longer referenced
		137	by any watcher and the loop object goes out of scope.
		138
		139	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		140	is recommended, as only the default event loop is protected by this
		141	module. If you I<are> embedding this loop in the default loop, this is not
		142	necessary, as C<EV::embed> automatically does the right thing on fork.
		143
		144	=item $loop->loop_fork
		145
		146	Must be called after a fork in the child, before entering or continuing
		147	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		148	this function automatically, at some performance loss (refer to the libev
		149	documentation).
		150
		151	=item $loop->loop_verify
		152
		153	Calls C<ev_verify> to make internal consistency checks (for debugging
		154	libev) and abort the program if any data structures were found to be
		155	corrupted.
		156
		157	=item $loop = EV::default_loop [$flags]
		158
		159	Return the default loop (which is a singleton object). Since this module
		160	already creates the default loop with default flags, specifying flags here
		161	will not have any effect unless you destroy the default loop first, which
		162	isn't supported. So in short: don't do it, and if you break it, you get to
		163	keep the pieces.
		164
		165	=back
		166
78		167
79	=head1 BASIC INTERFACE	168	=head1 BASIC INTERFACE
80		169
81	=over 4	170	=over 4
82		171
83	=item $EV::DIED	172	=item $EV::DIED
84		173
85	Must contain a reference to a function that is called when a callback	174	Must contain a reference to a function that is called when a callback
86	throws an exception (with $@ containing thr error). The default prints an	175	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	176	informative message and continues.
88		177
89	If this callback throws an exception it will be silently ignored.	178	If this callback throws an exception it will be silently ignored.
90		179
		180	=item $flags = EV::supported_backends
		181
		182	=item $flags = EV::recommended_backends
		183
		184	=item $flags = EV::embeddable_backends
		185
		186	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		187	instance of EV, the set of recommended backends (supposed to be good) for
		188	this platform and the set of embeddable backends (see EMBED WATCHERS).
		189
		190	=item EV::sleep $seconds
		191
		192	Block the process for the given number of (fractional) seconds.
		193
91	=item $time = EV::time	194	=item $time = EV::time
92		195
93	Returns the current time in (fractional) seconds since the epoch.	196	Returns the current time in (fractional) seconds since the epoch.
94		197
95	=item $time = EV::now	198	=item $time = EV::now
96		199
		200	=item $time = $loop->now
		201
97	Returns the time the last event loop iteration has been started. This	202	Returns the time the last event loop iteration has been started. This
98	is the time that (relative) timers are based on, and refering to it is	203	is the time that (relative) timers are based on, and referring to it is
99	usually faster then calling EV::time.	204	usually faster then calling EV::time.
100		205
101	=item $method = EV::ev_method	206	=item EV::now_update
102		207
		208	=item $loop->now_update
		209
		210	Establishes the current time by querying the kernel, updating the time
		211	returned by C<EV::now> in the progress. This is a costly operation and
		212	is usually done automatically within C<EV::loop>.
		213
		214	This function is rarely useful, but when some event callback runs for a
		215	very long time without entering the event loop, updating libev's idea of
		216	the current time is a good idea.
		217
		218	=item EV::suspend
		219
		220	=item $loop->suspend
		221
		222	=item EV::resume
		223
		224	=item $loop->resume
		225
		226	These two functions suspend and resume a loop, for use when the loop is
		227	not used for a while and timeouts should not be processed.
		228
		229	A typical use case would be an interactive program such as a game: When
		230	the user presses C<^Z> to suspend the game and resumes it an hour later it
		231	would be best to handle timeouts as if no time had actually passed while
		232	the program was suspended. This can be achieved by calling C<suspend>
		233	in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
		234	C<resume> directly afterwards to resume timer processing.
		235
		236	Effectively, all C<timer> watchers will be delayed by the time spend
		237	between C<suspend> and C<resume>, and all C<periodic> watchers
		238	will be rescheduled (that is, they will lose any events that would have
		239	occured while suspended).
		240
		241	After calling C<suspend> you B<must not> call I<any> function on the given
		242	loop other than C<resume>, and you B<must not> call C<resume>
		243	without a previous call to C<suspend>.
		244
		245	Calling C<suspend>/C<resume> has the side effect of updating the event
		246	loop time (see C<now_update>).
		247
		248	=item $backend = EV::backend
		249
		250	=item $backend = $loop->backend
		251
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	252	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
104	or EV::METHOD_EPOLL).	253	or EV::BACKEND_EPOLL).
105		254
106	=item EV::loop [$flags]	255	=item EV::loop [$flags]
107		256
		257	=item $loop->loop ([$flags])
		258
108	Begin checking for events and calling callbacks. It returns when a	259	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	260	callback calls EV::unloop.
110		261
111	The $flags argument can be one of the following:	262	The $flags argument can be one of the following:
112		263
113	0 as above	264	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	265	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	266	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		267
117	=item EV::loop_done [$how]	268	=item EV::unloop [$how]
118		269
		270	=item $loop->unloop ([$how])
		271
119	When called with no arguments or an argument of 1, makes the innermost	272	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	273	innermost call to EV::loop return.
121		274
122	When called with an agrument of 2, all calls to EV::loop will return as	275	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	276	fast as possible.
124		277
125	=back	278	=item $count = EV::loop_count
126		279
127	=head2 WATCHER	280	=item $count = $loop->loop_count
		281
		282	Return the number of times the event loop has polled for new
		283	events. Sometimes useful as a generation counter.
		284
		285	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		286
		287	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		288
		289	This function rolls together an I/O and a timer watcher for a single
		290	one-shot event without the need for managing a watcher object.
		291
		292	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		293	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		294	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		295	you do not want to wait for some I/O event, specify C<undef> for
		296	C<$fh_or_undef> and C<0> for C<$events>).
		297
		298	If timeout is C<undef> or negative, then there will be no
		299	timeout. Otherwise a EV::timer with this value will be started.
		300
		301	When an error occurs or either the timeout or I/O watcher triggers, then
		302	the callback will be called with the received event set (in general
		303	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		304	C<EV::WRITE> and C<EV::TIMER>).
		305
		306	EV::once doesn't return anything: the watchers stay active till either
		307	of them triggers, then they will be stopped and freed, and the callback
		308	invoked.
		309
		310	=item EV::feed_fd_event ($fd, $revents)
		311
		312	=item $loop->feed_fd_event ($fd, $revents)
		313
		314	Feed an event on a file descriptor into EV. EV will react to this call as
		315	if the readyness notifications specified by C<$revents> (a combination of
		316	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		317
		318	=item EV::feed_signal_event ($signal)
		319
		320	Feed a signal event into EV. EV will react to this call as if the signal
		321	specified by C<$signal> had occured.
		322
		323	=item EV::set_io_collect_interval $time
		324
		325	=item $loop->set_io_collect_interval ($time)
		326
		327	=item EV::set_timeout_collect_interval $time
		328
		329	=item $loop->set_timeout_collect_interval ($time)
		330
		331	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		332	wait interval for timer events. See the libev documentation at
		333	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		334	(locally installed as F<EV::libev>) for a more detailed discussion.
		335
		336	=item $count = EV::pending_count
		337
		338	=item $count = $loop->pending_count
		339
		340	Returns the number of currently pending watchers.
		341
		342	=item EV::invoke_pending
		343
		344	=item $loop->invoke_pending
		345
		346	Invoke all currently pending watchers.
		347
		348	=back
		349
		350
		351	=head1 WATCHER OBJECTS
128		352
129	A watcher is an object that gets created to record your interest in some	353	A watcher is an object that gets created to record your interest in some
130	event. For instance, if you want to wait for STDIN to become readable, you	354	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	355	would create an EV::io watcher for that:
132		356
133	my $watcher = EV::io *STDIN, EV::READ, sub {	357	my $watcher = EV::io *STDIN, EV::READ, sub {
134	my ($watcher, $revents) = @_;	358	my ($watcher, $revents) = @_;
135	warn "yeah, STDIN should not be readable without blocking!\n"	359	warn "yeah, STDIN should now be readable without blocking!\n"
136	};	360	};
137		361
138	All watchers can be active (waiting for events) or inactive (paused). Only	362	All watchers can be active (waiting for events) or inactive (paused). Only
139	active watchers will have their callbacks invoked. All callbacks will be	363	active watchers will have their callbacks invoked. All callbacks will be
140	called with at least two arguments: the watcher and a bitmask of received	364	called with at least two arguments: the watcher and a bitmask of received
141	events.	365	events.
142		366
143	Each watcher type has its associated bit in revents, so you can use the	367	Each watcher type has its associated bit in revents, so you can use the
144	same callback for multiple watchers. The event mask is named after the	368	same callback for multiple watchers. The event mask is named after the
145	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	369	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
146	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	370	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
147	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	371	(which can set both EV::READ and EV::WRITE bits).
148	uses EV::TIMEOUT).
149		372
150	In the rare case where one wants to create a watcher but not start it at	373	In the rare case where one wants to create a watcher but not start it at
151	the same time, each constructor has a variant with a trailing C<_ns> in	374	the same time, each constructor has a variant with a trailing C<_ns> in
152	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.	375	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
153		376
154	Please note that a watcher will automatically be stopped when the watcher	377	Please note that a watcher will automatically be stopped when the watcher
155	object is returned, so you I<need> to keep the watcher objects returned by	378	object is destroyed, so you I<need> to keep the watcher objects returned by
156	the constructors.	379	the constructors.
157		380
158	=head2 WATCHER TYPES	381	Also, all methods changing some aspect of a watcher (->set, ->priority,
		382	->fh and so on) automatically stop and start it again if it is active,
		383	which means pending events get lost.
159		384
160	Now lets move to the existing watcher types and asociated methods.	385	=head2 COMMON WATCHER METHODS
161		386
162	The following methods are available for all watchers. Then followes a	387	This section lists methods common to all watchers.
163	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
164	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
165	any type-specific methods (if any).
166		388
167	=over 4	389	=over 4
168		390
169	=item $w->start	391	=item $w->start
170		392
…		…
174		396
175	=item $w->stop	397	=item $w->stop
176		398
177	Stop a watcher if it is active. Also clear any pending events (events that	399	Stop a watcher if it is active. Also clear any pending events (events that
178	have been received but that didn't yet result in a callback invocation),	400	have been received but that didn't yet result in a callback invocation),
179	regardless of wether the watcher was active or not.	401	regardless of whether the watcher was active or not.
180		402
181	=item $bool = $w->is_active	403	=item $bool = $w->is_active
182		404
183	Returns true if the watcher is active, false otherwise.	405	Returns true if the watcher is active, false otherwise.
184		406
		407	=item $current_data = $w->data
		408
		409	=item $old_data = $w->data ($new_data)
		410
		411	Queries a freely usable data scalar on the watcher and optionally changes
		412	it. This is a way to associate custom data with a watcher:
		413
		414	my $w = EV::timer 60, 0, sub {
		415	warn $_[0]->data;
		416	};
		417	$w->data ("print me!");
		418
185	=item $current_cb = $w->cb	419	=item $current_cb = $w->cb
186		420
187	=item $old_cb = $w->cb ($new_cb)	421	=item $old_cb = $w->cb ($new_cb)
188		422
189	Queries the callback on the watcher and optionally changes it. You cna do	423	Queries the callback on the watcher and optionally changes it. You can do
190	this at any time.	424	this at any time without the watcher restarting.
191		425
		426	=item $current_priority = $w->priority
		427
		428	=item $old_priority = $w->priority ($new_priority)
		429
		430	Queries the priority on the watcher and optionally changes it. Pending
		431	watchers with higher priority will be invoked first. The valid range of
		432	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		433	-2). If the priority is outside this range it will automatically be
		434	normalised to the nearest valid priority.
		435
		436	The default priority of any newly-created watcher is 0.
		437
		438	Note that the priority semantics have not yet been fleshed out and are
		439	subject to almost certain change.
		440
192	=item $w->trigger ($revents)	441	=item $w->invoke ($revents)
193		442
194	Call the callback now with the given event mask.	443	Call the callback now with the given event mask.
195		444
		445	=item $w->feed_event ($revents)
		446
		447	Feed some events on this watcher into EV. EV will react to this call as if
		448	the watcher had received the given C<$revents> mask.
		449
		450	=item $revents = $w->clear_pending
		451
		452	If the watcher is pending, this function clears its pending status and
		453	returns its C<$revents> bitset (as if its callback was invoked). If the
		454	watcher isn't pending it does nothing and returns C<0>.
		455
		456	=item $previous_state = $w->keepalive ($bool)
		457
		458	Normally, C<EV::loop> will return when there are no active watchers
		459	(which is a "deadlock" because no progress can be made anymore). This is
		460	convenient because it allows you to start your watchers (and your jobs),
		461	call C<EV::loop> once and when it returns you know that all your jobs are
		462	finished (or they forgot to register some watchers for their task :).
		463
		464	Sometimes, however, this gets in your way, for example when the module
		465	that calls C<EV::loop> (usually the main program) is not the same module
		466	as a long-living watcher (for example a DNS client module written by
		467	somebody else even). Then you might want any outstanding requests to be
		468	handled, but you would not want to keep C<EV::loop> from returning just
		469	because you happen to have this long-running UDP port watcher.
		470
		471	In this case you can clear the keepalive status, which means that even
		472	though your watcher is active, it won't keep C<EV::loop> from returning.
		473
		474	The initial value for keepalive is true (enabled), and you can change it
		475	any time.
		476
		477	Example: Register an I/O watcher for some UDP socket but do not keep the
		478	event loop from running just because of that watcher.
		479
		480	my $udp_socket = ...
		481	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		482	$udp_watcher->keepalive (0);
		483
		484	=item $loop = $w->loop
		485
		486	Return the loop that this watcher is attached to.
		487
		488	=back
		489
		490
		491	=head1 WATCHER TYPES
		492
		493	Each of the following subsections describes a single watcher type.
		494
		495	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		496
		497	=over 4
196		498
197	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	499	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
198		500
199	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	501	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
200		502
		503	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		504
		505	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		506
201	As long as the returned watcher object is alive, call the C<$callback>	507	As long as the returned watcher object is alive, call the C<$callback>
202	when the events specified in C<$eventmask>.	508	when at least one of events specified in C<$eventmask> occurs.
203		509
204	The $eventmask can be one or more of these constants ORed together:	510	The $eventmask can be one or more of these constants ORed together:
205		511
206	EV::READ wait until read() wouldn't block anymore	512	EV::READ wait until read() wouldn't block anymore
207	EV::WRITE wait until write() wouldn't block anymore	513	EV::WRITE wait until write() wouldn't block anymore
…		…
223		529
224	=item $old_eventmask = $w->events ($new_eventmask)	530	=item $old_eventmask = $w->events ($new_eventmask)
225		531
226	Returns the previously set event mask and optionally set a new one.	532	Returns the previously set event mask and optionally set a new one.
227		533
		534	=back
		535
		536
		537	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		538
		539	=over 4
228		540
229	=item $w = EV::timer $after, $repeat, $callback	541	=item $w = EV::timer $after, $repeat, $callback
230		542
231	=item $w = EV::timer_ns $after, $repeat, $callback	543	=item $w = EV::timer_ns $after, $repeat, $callback
232		544
233	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	545	=item $w = $loop->timer ($after, $repeat, $callback)
234	the timer will be restarted (with the $repeat value as $after) after the	546
235	callback returns.	547	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		548
		549	Calls the callback after C<$after> seconds (which may be fractional). If
		550	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		551	value as $after) after the callback returns.
236		552
237	This means that the callback would be called roughly after C<$after>	553	This means that the callback would be called roughly after C<$after>
238	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	554	seconds, and then every C<$repeat> seconds. The timer does his best not
239	callback processing is not taken into account, so the timer will slowly	555	to drift, but it will not invoke the timer more often then once per event
240	drift. If that isn't acceptable, look at EV::periodic.	556	loop iteration, and might drift in other cases. If that isn't acceptable,
		557	look at EV::periodic, which can provide long-term stable timers.
241		558
242	The timer is based on a monotonic clock, that is if somebody is sitting	559	The timer is based on a monotonic clock, that is, if somebody is sitting
243	in front of the machine while the timer is running and changes the system	560	in front of the machine while the timer is running and changes the system
244	clock, the timer will nevertheless run (roughly) the same time.	561	clock, the timer will nevertheless run (roughly) the same time.
245		562
246	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	563	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
247		564
248	=item $w->set ($after, $repeat)	565	=item $w->set ($after, $repeat)
249		566
250	Reconfigures the watcher, see the constructor above for details. Can be at	567	Reconfigures the watcher, see the constructor above for details. Can be called at
251	any time.	568	any time.
252		569
253	=item $w->again	570	=item $w->again
254		571
255	Similar to the C<start> method, but has special semantics for repeating timers:	572	Similar to the C<start> method, but has special semantics for repeating timers:
		573
		574	If the timer is active and non-repeating, it will be stopped.
256		575
257	If the timer is active and repeating, reset the timeout to occur	576	If the timer is active and repeating, reset the timeout to occur
258	C<$repeat> seconds after now.	577	C<$repeat> seconds after now.
259		578
260	If the timer is active and non-repeating, it will be stopped.
261
262	If the timer is in active and repeating, start it.	579	If the timer is inactive and repeating, start it using the repeat value.
263		580
264	Otherwise do nothing.	581	Otherwise do nothing.
265		582
266	This behaviour is useful when you have a timeout for some IO	583	This behaviour is useful when you have a timeout for some IO
267	operation. You create a timer object with the same value for C<$after> and	584	operation. You create a timer object with the same value for C<$after> and
268	C<$repeat>, and then, in the read/write watcher, run the C<again> method	585	C<$repeat>, and then, in the read/write watcher, run the C<again> method
269	on the timeout.	586	on the timeout.
270		587
		588	=back
271		589
		590
		591	=head3 PERIODIC WATCHERS - to cron or not to cron?
		592
		593	=over 4
		594
272	=item $w = EV::periodic $at, $interval, $callback	595	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
273		596
274	=item $w = EV::periodic_ns $at, $interval, $callback	597	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
275		598
276	Similar to EV::timer, but the time is given as an absolute point in time	599	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
277	(C<$at>), plus an optional C<$interval>.
278		600
279	If the C<$interval> is zero, then the callback will be called at the time	601	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
280	C<$at> if that is in the future, or as soon as possible if it is in the
281	past. It will not automatically repeat.
282		602
283	If the C<$interval> is nonzero, then the watcher will always be scheduled	603	Similar to EV::timer, but is not based on relative timeouts but on
284	to time out at the next C<$at + N * $interval> time.	604	absolute times. Apart from creating "simple" timers that trigger "at" the
		605	specified time, it can also be used for non-drifting absolute timers and
		606	more complex, cron-like, setups that are not adversely affected by time
		607	jumps (i.e. when the system clock is changed by explicit date -s or other
		608	means such as ntpd). It is also the most complex watcher type in EV.
285		609
286	This can be used to schedule a callback to run at very regular intervals,	610	It has three distinct "modes":
287	as long as the processing time is less then the interval (otherwise	611
288	obviously events will be skipped).	612	=over 4
		613
		614	=item * absolute timer ($interval = $reschedule_cb = 0)
		615
		616	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		617	will not adjust when a time jump occurs, that is, if it is to be run
		618	at January 1st 2011 then it will run when the system time reaches or
		619	surpasses this time.
		620
		621	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
		622
		623	In this mode the watcher will always be scheduled to time out at the
		624	next C<$at + N * $interval> time (for some integer N) and then repeat,
		625	regardless of any time jumps.
		626
		627	This can be used to create timers that do not drift with respect to system
		628	time:
		629
		630	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		631
		632	That doesn't mean there will always be 3600 seconds in between triggers,
		633	but only that the the clalback will be called when the system time shows a
		634	full hour (UTC).
289		635
290	Another way to think about it (for the mathematically inclined) is that	636	Another way to think about it (for the mathematically inclined) is that
291	EV::periodic will try to run the callback at the next possible time where	637	EV::periodic will try to run the callback in this mode at the next
292	C<$time = $at (mod $interval)>, regardless of any time jumps.	638	possible time where C<$time = $at (mod $interval)>, regardless of any time
		639	jumps.
293		640
294	This periodic timer is based on "wallclock time", that is, if the clock	641	=item * manual reschedule mode ($reschedule_cb = coderef)
295	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	642
296	the specified time. This means it will never drift (it might jitter, but	643	In this mode $interval and $at are both being ignored. Instead, each
297	it will not drift).	644	time the periodic watcher gets scheduled, the reschedule callback
		645	($reschedule_cb) will be called with the watcher as first, and the current
		646	time as second argument.
		647
		648	I<This callback MUST NOT stop or destroy this or any other periodic
		649	watcher, ever, and MUST NOT call any event loop functions or methods>. If
		650	you need to stop it, return 1e30 and stop it afterwards. You may create
		651	and start a C<EV::prepare> watcher for this task.
		652
		653	It must return the next time to trigger, based on the passed time value
		654	(that is, the lowest time value larger than or equal to to the second
		655	argument). It will usually be called just before the callback will be
		656	triggered, but might be called at other times, too.
		657
		658	This can be used to create very complex timers, such as a timer that
		659	triggers on each midnight, local time (actually 24 hours after the last
		660	midnight, to keep the example simple. If you know a way to do it correctly
		661	in about the same space (without requiring elaborate modules), drop me a
		662	note :):
		663
		664	my $daily = EV::periodic 0, 0, sub {
		665	my ($w, $now) = @_;
		666
		667	use Time::Local ();
		668	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		669	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		670	}, sub {
		671	print "it's midnight or likely shortly after, now\n";
		672	};
		673
		674	=back
298		675
299	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	676	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
300		677
301	=item $w->set ($at, $interval)	678	=item $w->set ($at, $interval, $reschedule_cb)
302		679
303	Reconfigures the watcher, see the constructor above for details. Can be at	680	Reconfigures the watcher, see the constructor above for details. Can be called at
304	any time.	681	any time.
305		682
		683	=item $w->again
		684
		685	Simply stops and starts the watcher again.
		686
		687	=item $time = $w->at
		688
		689	Return the time that the watcher is expected to trigger next.
		690
		691	=back
		692
		693
		694	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		695
		696	=over 4
306		697
307	=item $w = EV::signal $signal, $callback	698	=item $w = EV::signal $signal, $callback
308		699
309	=item $w = EV::signal_ns $signal, $callback	700	=item $w = EV::signal_ns $signal, $callback
310		701
		702	=item $w = $loop->signal ($signal, $callback)
		703
		704	=item $w = $loop->signal_ns ($signal, $callback)
		705
311	Call the callback when $signal is received (the signal can be specified	706	Call the callback when $signal is received (the signal can be specified by
312	by number or by name, just as with kill or %SIG).	707	number or by name, just as with C<kill> or C<%SIG>).
		708
		709	Only one event loop can grab a given signal - attempting to grab the same
		710	signal from two EV loops will crash the program immediately or cause data
		711	corruption.
313		712
314	EV will grab the signal for the process (the kernel only allows one	713	EV will grab the signal for the process (the kernel only allows one
315	component to receive a signal at a time) when you start a signal watcher,	714	component to receive a signal at a time) when you start a signal watcher,
316	and removes it again when you stop it. Perl does the same when you	715	and removes it again when you stop it. Perl does the same when you
317	add/remove callbacks to %SIG, so watch out.	716	add/remove callbacks to C<%SIG>, so watch out.
318		717
319	You can have as many signal watchers per signal as you want.	718	You can have as many signal watchers per signal as you want.
320		719
321	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	720	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
322		721
323	=item $w->set ($signal)	722	=item $w->set ($signal)
324		723
325	Reconfigures the watcher, see the constructor above for details. Can be at	724	Reconfigures the watcher, see the constructor above for details. Can be
		725	called at any time.
		726
		727	=item $current_signum = $w->signal
		728
		729	=item $old_signum = $w->signal ($new_signal)
		730
		731	Returns the previously set signal (always as a number not name) and
		732	optionally set a new one.
		733
		734	=back
		735
		736
		737	=head3 CHILD WATCHERS - watch out for process status changes
		738
		739	=over 4
		740
		741	=item $w = EV::child $pid, $trace, $callback
		742
		743	=item $w = EV::child_ns $pid, $trace, $callback
		744
		745	=item $w = $loop->child ($pid, $trace, $callback)
		746
		747	=item $w = $loop->child_ns ($pid, $trace, $callback)
		748
		749	Call the callback when a status change for pid C<$pid> (or any pid
		750	if C<$pid> is 0) has been received (a status change happens when the
		751	process terminates or is killed, or, when trace is true, additionally when
		752	it is stopped or continued). More precisely: when the process receives
		753	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
		754	changed/zombie children and call the callback.
		755
		756	It is valid (and fully supported) to install a child watcher after a child
		757	has exited but before the event loop has started its next iteration (for
		758	example, first you C<fork>, then the new child process might exit, and
		759	only then do you install a child watcher in the parent for the new pid).
		760
		761	You can access both exit (or tracing) status and pid by using the
		762	C<rstatus> and C<rpid> methods on the watcher object.
		763
		764	You can have as many pid watchers per pid as you want, they will all be
		765	called.
		766
		767	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		768
		769	=item $w->set ($pid, $trace)
		770
		771	Reconfigures the watcher, see the constructor above for details. Can be called at
326	any time.	772	any time.
327		773
		774	=item $current_pid = $w->pid
328		775
329	=item $w = EV::child $pid, $callback	776	Returns the previously set process id and optionally set a new one.
330		777
331	=item $w = EV::child_ns $pid, $callback	778	=item $exit_status = $w->rstatus
332		779
333	Call the callback when a status change for pid C<$pid> (or any pid	780	Return the exit/wait status (as returned by waitpid, see the waitpid entry
334	if C<$pid> is 0) has been received. More precisely: when the process	781	in perlfunc).
335	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all
336	changed/zombie children and call the callback.
337		782
338	Unlike all other callbacks, this callback will be called with an	783	=item $pid = $w->rpid
339	additional third argument which is the exit status. See the C<waitpid>
340	function for details.
341		784
342	You can have as many pid watchers per pid as you want.	785	Return the pid of the awaited child (useful when you have installed a
		786	watcher for all pids).
343		787
		788	=back
		789
		790
		791	=head3 STAT WATCHERS - did the file attributes just change?
		792
		793	=over 4
		794
		795	=item $w = EV::stat $path, $interval, $callback
		796
		797	=item $w = EV::stat_ns $path, $interval, $callback
		798
		799	=item $w = $loop->stat ($path, $interval, $callback)
		800
		801	=item $w = $loop->stat_ns ($path, $interval, $callback)
		802
		803	Call the callback when a file status change has been detected on
		804	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		805	to "path does not exist" is a status change like any other.
		806
		807	The C<$interval> is a recommended polling interval for systems where
		808	OS-supported change notifications don't exist or are not supported. If
		809	you use C<0> then an unspecified default is used (which is highly
		810	recommended!), which is to be expected to be around five seconds usually.
		811
		812	This watcher type is not meant for massive numbers of stat watchers,
		813	as even with OS-supported change notifications, this can be
		814	resource-intensive.
		815
344	The C<child_ns> variant doesn't start (activate) the newly created watcher.	816	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
345		817
346	=item $w->set ($pid)	818	=item ... = $w->stat
347		819
		820	This call is very similar to the perl C<stat> built-in: It stats (using
		821	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		822	well as EV's idea of the current stat values) to the values found.
		823
		824	In scalar context, a boolean is return indicating success or failure of
		825	the stat. In list context, the same 13-value list as with stat is returned
		826	(except that the blksize and blocks fields are not reliable).
		827
		828	In the case of an error, errno is set to C<ENOENT> (regardless of the
		829	actual error value) and the C<nlink> value is forced to zero (if the stat
		830	was successful then nlink is guaranteed to be non-zero).
		831
		832	See also the next two entries for more info.
		833
		834	=item ... = $w->attr
		835
		836	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		837	the values most recently detected by EV. See the next entry for more info.
		838
		839	=item ... = $w->prev
		840
		841	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		842	the previous set of values, before the change.
		843
		844	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		845	to the values found I<before> a change was detected, while C<< $w->attr >>
		846	returns the values found leading to the change detection. The difference (if any)
		847	between C<prev> and C<attr> is what triggered the callback.
		848
		849	If you did something to the filesystem object and do not want to trigger
		850	yet another change, you can call C<stat> to update EV's idea of what the
		851	current attributes are.
		852
		853	=item $w->set ($path, $interval)
		854
348	Reconfigures the watcher, see the constructor above for details. Can be at	855	Reconfigures the watcher, see the constructor above for details. Can be
349	any time.	856	called at any time.
350		857
		858	=item $current_path = $w->path
		859
		860	=item $old_path = $w->path ($new_path)
		861
		862	Returns the previously set path and optionally set a new one.
		863
		864	=item $current_interval = $w->interval
		865
		866	=item $old_interval = $w->interval ($new_interval)
		867
		868	Returns the previously set interval and optionally set a new one. Can be
		869	used to query the actual interval used.
		870
		871	=back
		872
		873
		874	=head3 IDLE WATCHERS - when you've got nothing better to do...
		875
		876	=over 4
351		877
352	=item $w = EV::idle $callback	878	=item $w = EV::idle $callback
353		879
354	=item $w = EV::idle_ns $callback	880	=item $w = EV::idle_ns $callback
355		881
356	Call the callback when there are no pending io, timer/periodic, signal or	882	=item $w = $loop->idle ($callback)
357	child events, i.e. when the process is idle.	883
		884	=item $w = $loop->idle_ns ($callback)
		885
		886	Call the callback when there are no other pending watchers of the same or
		887	higher priority (excluding check, prepare and other idle watchers of the
		888	same or lower priority, of course). They are called idle watchers because
		889	when the watcher is the highest priority pending event in the process, the
		890	process is considered to be idle at that priority.
		891
		892	If you want a watcher that is only ever called when I<no> other events are
		893	outstanding you have to set the priority to C<EV::MINPRI>.
358		894
359	The process will not block as long as any idle watchers are active, and	895	The process will not block as long as any idle watchers are active, and
360	they will be called repeatedly until stopped.	896	they will be called repeatedly until stopped.
361		897
		898	For example, if you have idle watchers at priority C<0> and C<1>, and
		899	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		900	and the I/O watcher will always run when ready. Only when the idle watcher
		901	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		902	pending with the C<0>-priority idle watcher be invoked.
		903
362	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	904	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
363		905
		906	=back
		907
		908
		909	=head3 PREPARE WATCHERS - customise your event loop!
		910
		911	=over 4
364		912
365	=item $w = EV::prepare $callback	913	=item $w = EV::prepare $callback
366		914
367	=item $w = EV::prepare_ns $callback	915	=item $w = EV::prepare_ns $callback
		916
		917	=item $w = $loop->prepare ($callback)
		918
		919	=item $w = $loop->prepare_ns ($callback)
368		920
369	Call the callback just before the process would block. You can still	921	Call the callback just before the process would block. You can still
370	create/modify any watchers at this point.	922	create/modify any watchers at this point.
371		923
372	See the EV::check watcher, below, for explanations and an example.	924	See the EV::check watcher, below, for explanations and an example.
373		925
374	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	926	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
375		927
		928	=back
		929
		930
		931	=head3 CHECK WATCHERS - customise your event loop even more!
		932
		933	=over 4
376		934
377	=item $w = EV::check $callback	935	=item $w = EV::check $callback
378		936
379	=item $w = EV::check_ns $callback	937	=item $w = EV::check_ns $callback
		938
		939	=item $w = $loop->check ($callback)
		940
		941	=item $w = $loop->check_ns ($callback)
380		942
381	Call the callback just after the process wakes up again (after it has	943	Call the callback just after the process wakes up again (after it has
382	gathered events), but before any other callbacks have been invoked.	944	gathered events), but before any other callbacks have been invoked.
383		945
384	This is used to integrate other event-based software into the EV	946	This is used to integrate other event-based software into the EV
…		…
392	# do nothing unless active	954	# do nothing unless active
393	$dispatcher->{_event_queue_h}	955	$dispatcher->{_event_queue_h}
394	or return;	956	or return;
395		957
396	# make the dispatcher handle any outstanding stuff	958	# make the dispatcher handle any outstanding stuff
		959	... not shown
397		960
398	# create an IO watcher for each and every socket	961	# create an I/O watcher for each and every socket
399	@snmp_watcher = (	962	@snmp_watcher = (
400	(map { EV::io $_, EV::READ, sub { } }	963	(map { EV::io $_, EV::READ, sub { } }
401	keys %{ $dispatcher->{_descriptors} }),	964	keys %{ $dispatcher->{_descriptors} }),
		965
		966	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		967	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		968	0, sub { },
402	);	969	);
403
404	# if there are any timeouts, also create a timer
405	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
406	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
407	};	970	};
408		971
409	The callbacks are irrelevant, the only purpose of those watchers is	972	The callbacks are irrelevant (and are not even being called), the
410	to wake up the process as soon as one of those events occurs (socket	973	only purpose of those watchers is to wake up the process as soon as
411	readable, or timer timed out). The corresponding EV::check watcher will then	974	one of those events occurs (socket readable, or timer timed out). The
412	clean up:	975	corresponding EV::check watcher will then clean up:
413		976
414	our $snmp_check = EV::check sub {	977	our $snmp_check = EV::check sub {
415	# destroy all watchers	978	# destroy all watchers
416	@snmp_watcher = ();	979	@snmp_watcher = ();
417		980
418	# make the dispatcher handle any new stuff	981	# make the dispatcher handle any new stuff
		982	... not shown
419	};	983	};
420		984
421	The callbacks of the created watchers will not be called as the watchers	985	The callbacks of the created watchers will not be called as the watchers
422	are destroyed before this cna happen (remember EV::check gets called	986	are destroyed before this can happen (remember EV::check gets called
423	first).	987	first).
424		988
425	The C<check_ns> variant doesn't start (activate) the newly created watcher.	989	The C<check_ns> variant doesn't start (activate) the newly created watcher.
426		990
427	=back	991	=back
428		992
		993
		994	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		995
		996	Fork watchers are called when a C<fork ()> was detected. The invocation
		997	is done before the event loop blocks next and before C<check> watchers
		998	are being called, and only in the child after the fork.
		999
		1000	=over 4
		1001
		1002	=item $w = EV::fork $callback
		1003
		1004	=item $w = EV::fork_ns $callback
		1005
		1006	=item $w = $loop->fork ($callback)
		1007
		1008	=item $w = $loop->fork_ns ($callback)
		1009
		1010	Call the callback before the event loop is resumed in the child process
		1011	after a fork.
		1012
		1013	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		1014
		1015	=back
		1016
		1017
		1018	=head3 EMBED WATCHERS - when one backend isn't enough...
		1019
		1020	This is a rather advanced watcher type that lets you embed one event loop
		1021	into another (currently only IO events are supported in the embedded
		1022	loop, other types of watchers might be handled in a delayed or incorrect
		1023	fashion and must not be used).
		1024
		1025	See the libev documentation at
		1026	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1027	(locally installed as F<EV::libev>) for more details.
		1028
		1029	In short, this watcher is most useful on BSD systems without working
		1030	kqueue to still be able to handle a large number of sockets:
		1031
		1032	my $socket_loop;
		1033
		1034	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1035	if (
		1036	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1037	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1038	) {
		1039	# use kqueue for sockets
		1040	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1041	}
		1042
		1043	# use the default loop otherwise
		1044	$socket_loop \|\|= EV::default_loop;
		1045
		1046	=over 4
		1047
		1048	=item $w = EV::embed $otherloop[, $callback]
		1049
		1050	=item $w = EV::embed_ns $otherloop[, $callback]
		1051
		1052	=item $w = $loop->embed ($otherloop[, $callback])
		1053
		1054	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1055
		1056	Call the callback when the embedded event loop (C<$otherloop>) has any
		1057	I/O activity. The C<$callback> is optional: if it is missing, then the
		1058	embedded event loop will be managed automatically (which is recommended),
		1059	otherwise you have to invoke C<sweep> yourself.
		1060
		1061	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1062
		1063	=back
		1064
		1065	=head3 ASYNC WATCHERS - how to wake up another event loop
		1066
		1067	Async watchers are provided by EV, but have little use in perl directly,
		1068	as perl neither supports threads running in parallel nor direct access to
		1069	signal handlers or other contexts where they could be of value.
		1070
		1071	It is, however, possible to use them from the XS level.
		1072
		1073	Please see the libev documentation for further details.
		1074
		1075	=over 4
		1076
		1077	=item $w = EV::async $callback
		1078
		1079	=item $w = EV::async_ns $callback
		1080
		1081	=item $w->send
		1082
		1083	=item $bool = $w->async_pending
		1084
		1085	=back
		1086
		1087
		1088	=head1 PERL SIGNALS
		1089
		1090	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1091	with EV is as the same as any other C library: Perl-signals will only be
		1092	handled when Perl runs, which means your signal handler might be invoked
		1093	only the next time an event callback is invoked.
		1094
		1095	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1096	ensure proper operations with regards to other event watchers.
		1097
		1098	If you cannot do this for whatever reason, you can also force a watcher
		1099	to be called on every event loop iteration by installing a C<EV::check>
		1100	watcher:
		1101
		1102	my $async_check = EV::check sub { };
		1103
		1104	This ensures that perl gets into control for a short time to handle any
		1105	pending signals, and also ensures (slightly) slower overall operation.
		1106
429	=head1 THREADS	1107	=head1 ITHREADS
430		1108
431	Threads are not supported by this in any way. Perl pseudo-threads is evil	1109	Ithreads are not supported by this module in any way. Perl pseudo-threads
432	stuff and must die.	1110	is evil stuff and must die. Real threads as provided by Coro are fully
		1111	supported (and enhanced support is available via L<Coro::EV>).
		1112
		1113	=head1 FORK
		1114
		1115	Most of the "improved" event delivering mechanisms of modern operating
		1116	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1117	not supported and usually destructive). Libev makes it possible to work
		1118	around this by having a function that recreates the kernel state after
		1119	fork in the child.
		1120
		1121	On non-win32 platforms, this module requires the pthread_atfork
		1122	functionality to do this automatically for you. This function is quite
		1123	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1124	negligible, because everything the function currently does is set a flag
		1125	that is checked only when the event loop gets used the next time, so when
		1126	you do fork but not use EV, the overhead is minimal.
		1127
		1128	On win32, there is no notion of fork so all this doesn't apply, of course.
433		1129
434	=cut	1130	=cut
435		1131
436	our $DIED = sub {	1132	our $DIED = sub {
437	warn "EV: error in callback (ignoring): $@";	1133	warn "EV: error in callback (ignoring): $@";
438	};	1134	};
439		1135
440	init;	1136	default_loop
441		1137	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
442	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
443		1138
444	1;	1139	1;
445		1140
446	=head1 SEE ALSO	1141	=head1 SEE ALSO
447		1142
448	L<EV::DNS>, L<EV::AnyEvent>.	1143	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1144	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1145	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1146	event-loop agnostic and portable event driven programming.
449		1147
450	=head1 AUTHOR	1148	=head1 AUTHOR
451		1149
452	Marc Lehmann <schmorp@schmorp.de>	1150	Marc Lehmann <schmorp@schmorp.de>
453	http://home.schmorp.de/	1151	http://home.schmorp.de/
454		1152
455	=cut	1153	=cut
456		1154

Diff Legend

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

Comparing EV/EV.pm (file contents): Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs. Revision 1.126 by root, Tue Mar 16 17:11:48 2010 UTC

Diff Legend

Comparing EV/EV.pm (file contents):
Revision 1.21 by root, Thu Nov 1 17:20:25 2007 UTC vs.
Revision 1.126 by root, Tue Mar 16 17:11:48 2010 UTC