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

Comparing EV/EV.pm (file contents):
Revision 1.11 by root, Mon Oct 29 07:56:03 2007 UTC vs.
Revision 1.127 by root, Sun Mar 28 15:48:21 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	EV - perl interface to libevent, monkey.org/~provos/libevent/	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	# TIMER	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, 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::timer_abs 0, 60, sub {
22	warn "is called every minute, on the minute, exactly";
23	};
24
25	# IO
26
27	my $w = EV::io \*STDIN, EV::READ \| EV::PERSIST, sub {
28	my ($w, $events) = @_; # all callbacks get the watcher object and event mask
29	if ($events & EV::TIMEOUT) {
30	warn "nothing received on stdin for 10 seconds, retrying";
31	} else {
32	warn "stdin is readable, you entered: ", <STDIN>;
33	}
34	};
35	$w->timeout (10);
36
37	my $w = EV::timed_io \*STDIN, EV::READ, 30, sub {
38	my ($w, $events) = @_;	47	my ($w, $revents) = @_;
39	if ($_[1] & EV::TIMEOUT) {	48	warn $w->path, " has changed somehow.\n";
40	warn "nothing entered within 30 seconds, bye bye.\n";
41	$w->stop;
42	} else {
43	my $line = <STDIN>;
44	warn "you entered something, you again have 30 seconds.\n";
45	}
46	};	49	};
47		50
48	# SIGNALS
49
50	my $w = EV::signal 'QUIT', sub {
51	warn "sigquit received\n";
52	};
53
54	my $w = EV::signal 3, sub {
55	warn "sigquit received (this is GNU/Linux, right?)\n";
56	};
57
58	# MAINLOOP	51	# MAINLOOP
59	EV::dispatch; # loop as long as watchers are active	52	EV::loop; # loop until EV::unloop is called or all watchers stop
60	EV::loop; # the same thing
61	EV::loop EV::LOOP_ONCE; # block until some events could be handles	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
62	EV::loop EV::LOOP_NONBLOCK; # check and handle some events, but do not wait	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
		55
		56	=head1 BEFORE YOU START USING THIS MODULE
		57
		58	If you only need timer, I/O, signal, child and idle watchers and not the
		59	advanced functionality of this module, consider using L<AnyEvent> instead,
		60	specifically the simplified API described in L<AE>.
		61
		62	When used with EV as backend, the L<AE> API is as fast as the native L<EV>
		63	API, but your programs/modules will still run with many other event loops.
63		64
64	=head1 DESCRIPTION	65	=head1 DESCRIPTION
65		66
66	This module provides an interface to libevent	67	This module provides an interface to libev
67	(L<http://monkey.org/~provos/libevent/>). You probably should acquaint	68	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
68	yourself with its documentation and source code to be able to use this	69	below is comprehensive, one might also consult the documentation of
69	module fully.	70	libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
		71	F<perldoc EV::libev>) for more subtle details on watcher semantics or some
		72	discussion on the available backends, or how to force a specific backend
		73	with C<LIBEV_FLAGS>, or just about in any case because it has much more
		74	detailed information.
70		75
71	Please note thta this module disables the libevent EPOLL method by	76	This module is very fast and scalable. It is actually so fast that you
72	default, see BUGS, below, if you need to enable it.	77	can use it through the L<AnyEvent> module, stay portable to other event
		78	loops (if you don't rely on any watcher types not available through it)
		79	and still be faster than with any other event loop currently supported in
		80	Perl.
		81
		82	=head2 MODULE EXPORTS
		83
		84	This module does not export any symbols.
73		85
74	=cut	86	=cut
75		87
76	package EV;	88	package EV;
77		89
78	use strict;	90	use common::sense;
79		91
80	BEGIN {	92	BEGIN {
81	our $VERSION = '0.02';	93	our $VERSION = '4.00';
82	use XSLoader;	94	use XSLoader;
83	XSLoader::load "EV", $VERSION;	95	XSLoader::load "EV", $VERSION;
84	}	96	}
85		97
		98	@EV::IO::ISA =
		99	@EV::Timer::ISA =
		100	@EV::Periodic::ISA =
		101	@EV::Signal::ISA =
		102	@EV::Child::ISA =
		103	@EV::Stat::ISA =
		104	@EV::Idle::ISA =
		105	@EV::Prepare::ISA =
		106	@EV::Check::ISA =
		107	@EV::Embed::ISA =
		108	@EV::Fork::ISA =
		109	@EV::Async::ISA =
		110	"EV::Watcher";
		111
		112	@EV::Loop::Default::ISA = "EV::Loop";
		113
		114	=head1 EVENT LOOPS
		115
		116	EV supports multiple event loops: There is a single "default event loop"
		117	that can handle everything including signals and child watchers, and any
		118	number of "dynamic event loops" that can use different backends (with
		119	various limitations), but no child and signal watchers.
		120
		121	You do not have to do anything to create the default event loop: When
		122	the module is loaded a suitable backend is selected on the premise of
		123	selecting a working backend (which for example rules out kqueue on most
		124	BSDs). Modules should, unless they have "special needs" always use the
		125	default loop as this is fastest (perl-wise), best supported by other
		126	modules (e.g. AnyEvent or Coro) and most portable event loop.
		127
		128	For specific programs you can create additional event loops dynamically.
		129
		130	If you want to take advantage of kqueue (which often works properly for
		131	sockets only) even though the default loop doesn't enable it, you can
		132	I<embed> a kqueue loop into the default loop: running the default loop
		133	will then also service the kqueue loop to some extent. See the example in
		134	the section about embed watchers for an example on how to achieve that.
		135
		136	=over 4
		137
		138	=item $loop = new EV::Loop [$flags]
		139
		140	Create a new event loop as per the specified flags. Please refer to
		141	the C<ev_loop_new ()> function description in the libev documentation
		142	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
		143	or locally-installed as F<EV::libev> manpage) for more info.
		144
		145	The loop will automatically be destroyed when it is no longer referenced
		146	by any watcher and the loop object goes out of scope.
		147
		148	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		149	is recommended, as only the default event loop is protected by this
		150	module. If you I<are> embedding this loop in the default loop, this is not
		151	necessary, as C<EV::embed> automatically does the right thing on fork.
		152
		153	=item $loop->loop_fork
		154
		155	Must be called after a fork in the child, before entering or continuing
		156	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		157	this function automatically, at some performance loss (refer to the libev
		158	documentation).
		159
		160	=item $loop->loop_verify
		161
		162	Calls C<ev_verify> to make internal consistency checks (for debugging
		163	libev) and abort the program if any data structures were found to be
		164	corrupted.
		165
		166	=item $loop = EV::default_loop [$flags]
		167
		168	Return the default loop (which is a singleton object). Since this module
		169	already creates the default loop with default flags, specifying flags here
		170	will not have any effect unless you destroy the default loop first, which
		171	isn't supported. So in short: don't do it, and if you break it, you get to
		172	keep the pieces.
		173
		174	=back
		175
		176
86	=head1 BASIC INTERFACE	177	=head1 BASIC INTERFACE
87		178
88	=over 4	179	=over 4
89		180
90	=item $EV::NPRI
91
92	How many priority levels are available.
93
94	=item $EV::DIED	181	=item $EV::DIED
95		182
96	Must contain a reference to a function that is called when a callback	183	Must contain a reference to a function that is called when a callback
97	throws an exception (with $@ containing thr error). The default prints an	184	throws an exception (with $@ containing the error). The default prints an
98	informative message and continues.	185	informative message and continues.
99		186
100	If this callback throws an exception it will be silently ignored.	187	If this callback throws an exception it will be silently ignored.
101		188
		189	=item $flags = EV::supported_backends
		190
		191	=item $flags = EV::recommended_backends
		192
		193	=item $flags = EV::embeddable_backends
		194
		195	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		196	instance of EV, the set of recommended backends (supposed to be good) for
		197	this platform and the set of embeddable backends (see EMBED WATCHERS).
		198
		199	=item EV::sleep $seconds
		200
		201	Block the process for the given number of (fractional) seconds.
		202
		203	=item $time = EV::time
		204
		205	Returns the current time in (fractional) seconds since the epoch.
		206
102	=item $time = EV::now	207	=item $time = EV::now
103		208
104	Returns the time in (fractional) seconds since the epoch.	209	=item $time = $loop->now
105		210
106	=item $version = EV::version	211	Returns the time the last event loop iteration has been started. This
		212	is the time that (relative) timers are based on, and referring to it is
		213	usually faster then calling EV::time.
107		214
108	=item $method = EV::method	215	=item EV::now_update
109		216
110	Return version string and event polling method used.	217	=item $loop->now_update
111		218
112	=item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT	219	Establishes the current time by querying the kernel, updating the time
		220	returned by C<EV::now> in the progress. This is a costly operation and
		221	is usually done automatically within C<EV::loop>.
113		222
114	=item EV::loopexit $after	223	This function is rarely useful, but when some event callback runs for a
		224	very long time without entering the event loop, updating libev's idea of
		225	the current time is a good idea.
115		226
116	Exit any active loop or dispatch after C<$after> seconds or immediately if	227	=item EV::suspend
117	C<$after> is missing or zero.
118		228
119	=item EV::dispatch	229	=item $loop->suspend
120		230
121	Same as C<EV::loop 0>.	231	=item EV::resume
122		232
123	=item EV::event $callback	233	=item $loop->resume
124		234
125	Creates a new event watcher waiting for nothing, calling the given callback.	235	These two functions suspend and resume a loop, for use when the loop is
		236	not used for a while and timeouts should not be processed.
126		237
		238	A typical use case would be an interactive program such as a game: When
		239	the user presses C<^Z> to suspend the game and resumes it an hour later it
		240	would be best to handle timeouts as if no time had actually passed while
		241	the program was suspended. This can be achieved by calling C<suspend>
		242	in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
		243	C<resume> directly afterwards to resume timer processing.
		244
		245	Effectively, all C<timer> watchers will be delayed by the time spend
		246	between C<suspend> and C<resume>, and all C<periodic> watchers
		247	will be rescheduled (that is, they will lose any events that would have
		248	occured while suspended).
		249
		250	After calling C<suspend> you B<must not> call I<any> function on the given
		251	loop other than C<resume>, and you B<must not> call C<resume>
		252	without a previous call to C<suspend>.
		253
		254	Calling C<suspend>/C<resume> has the side effect of updating the event
		255	loop time (see C<now_update>).
		256
		257	=item $backend = EV::backend
		258
		259	=item $backend = $loop->backend
		260
		261	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
		262	or EV::BACKEND_EPOLL).
		263
		264	=item EV::loop [$flags]
		265
		266	=item $loop->loop ([$flags])
		267
		268	Begin checking for events and calling callbacks. It returns when a
		269	callback calls EV::unloop.
		270
		271	The $flags argument can be one of the following:
		272
		273	0 as above
		274	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
		275	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
		276
		277	=item EV::unloop [$how]
		278
		279	=item $loop->unloop ([$how])
		280
		281	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
		282	innermost call to EV::loop return.
		283
		284	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
		285	fast as possible.
		286
		287	=item $count = EV::loop_count
		288
		289	=item $count = $loop->loop_count
		290
		291	Return the number of times the event loop has polled for new
		292	events. Sometimes useful as a generation counter.
		293
		294	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		295
		296	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		297
		298	This function rolls together an I/O and a timer watcher for a single
		299	one-shot event without the need for managing a watcher object.
		300
		301	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		302	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		303	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		304	you do not want to wait for some I/O event, specify C<undef> for
		305	C<$fh_or_undef> and C<0> for C<$events>).
		306
		307	If timeout is C<undef> or negative, then there will be no
		308	timeout. Otherwise a EV::timer with this value will be started.
		309
		310	When an error occurs or either the timeout or I/O watcher triggers, then
		311	the callback will be called with the received event set (in general
		312	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		313	C<EV::WRITE> and C<EV::TIMER>).
		314
		315	EV::once doesn't return anything: the watchers stay active till either
		316	of them triggers, then they will be stopped and freed, and the callback
		317	invoked.
		318
		319	=item EV::feed_fd_event ($fd, $revents)
		320
		321	=item $loop->feed_fd_event ($fd, $revents)
		322
		323	Feed an event on a file descriptor into EV. EV will react to this call as
		324	if the readyness notifications specified by C<$revents> (a combination of
		325	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		326
		327	=item EV::feed_signal_event ($signal)
		328
		329	Feed a signal event into EV. EV will react to this call as if the signal
		330	specified by C<$signal> had occured.
		331
		332	=item EV::set_io_collect_interval $time
		333
		334	=item $loop->set_io_collect_interval ($time)
		335
		336	=item EV::set_timeout_collect_interval $time
		337
		338	=item $loop->set_timeout_collect_interval ($time)
		339
		340	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		341	wait interval for timer events. See the libev documentation at
		342	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		343	(locally installed as F<EV::libev>) for a more detailed discussion.
		344
		345	=item $count = EV::pending_count
		346
		347	=item $count = $loop->pending_count
		348
		349	Returns the number of currently pending watchers.
		350
		351	=item EV::invoke_pending
		352
		353	=item $loop->invoke_pending
		354
		355	Invoke all currently pending watchers.
		356
		357	=back
		358
		359
		360	=head1 WATCHER OBJECTS
		361
		362	A watcher is an object that gets created to record your interest in some
		363	event. For instance, if you want to wait for STDIN to become readable, you
		364	would create an EV::io watcher for that:
		365
		366	my $watcher = EV::io *STDIN, EV::READ, sub {
		367	my ($watcher, $revents) = @_;
		368	warn "yeah, STDIN should now be readable without blocking!\n"
		369	};
		370
		371	All watchers can be active (waiting for events) or inactive (paused). Only
		372	active watchers will have their callbacks invoked. All callbacks will be
		373	called with at least two arguments: the watcher and a bitmask of received
		374	events.
		375
		376	Each watcher type has its associated bit in revents, so you can use the
		377	same callback for multiple watchers. The event mask is named after the
		378	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
		379	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
		380	(which can set both EV::READ and EV::WRITE bits).
		381
		382	In the rare case where one wants to create a watcher but not start it at
		383	the same time, each constructor has a variant with a trailing C<_ns> in
		384	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
		385
		386	Please note that a watcher will automatically be stopped when the watcher
		387	object is destroyed, so you I<need> to keep the watcher objects returned by
		388	the constructors.
		389
		390	Also, all methods changing some aspect of a watcher (->set, ->priority,
		391	->fh and so on) automatically stop and start it again if it is active,
		392	which means pending events get lost.
		393
		394	=head2 COMMON WATCHER METHODS
		395
		396	This section lists methods common to all watchers.
		397
		398	=over 4
		399
		400	=item $w->start
		401
		402	Starts a watcher if it isn't active already. Does nothing to an already
		403	active watcher. By default, all watchers start out in the active state
		404	(see the description of the C<_ns> variants if you need stopped watchers).
		405
		406	=item $w->stop
		407
		408	Stop a watcher if it is active. Also clear any pending events (events that
		409	have been received but that didn't yet result in a callback invocation),
		410	regardless of whether the watcher was active or not.
		411
		412	=item $bool = $w->is_active
		413
		414	Returns true if the watcher is active, false otherwise.
		415
		416	=item $current_data = $w->data
		417
		418	=item $old_data = $w->data ($new_data)
		419
		420	Queries a freely usable data scalar on the watcher and optionally changes
		421	it. This is a way to associate custom data with a watcher:
		422
		423	my $w = EV::timer 60, 0, sub {
		424	warn $_[0]->data;
		425	};
		426	$w->data ("print me!");
		427
		428	=item $current_cb = $w->cb
		429
		430	=item $old_cb = $w->cb ($new_cb)
		431
		432	Queries the callback on the watcher and optionally changes it. You can do
		433	this at any time without the watcher restarting.
		434
		435	=item $current_priority = $w->priority
		436
		437	=item $old_priority = $w->priority ($new_priority)
		438
		439	Queries the priority on the watcher and optionally changes it. Pending
		440	watchers with higher priority will be invoked first. The valid range of
		441	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		442	-2). If the priority is outside this range it will automatically be
		443	normalised to the nearest valid priority.
		444
		445	The default priority of any newly-created watcher is 0.
		446
		447	Note that the priority semantics have not yet been fleshed out and are
		448	subject to almost certain change.
		449
		450	=item $w->invoke ($revents)
		451
		452	Call the callback now with the given event mask.
		453
		454	=item $w->feed_event ($revents)
		455
		456	Feed some events on this watcher into EV. EV will react to this call as if
		457	the watcher had received the given C<$revents> mask.
		458
		459	=item $revents = $w->clear_pending
		460
		461	If the watcher is pending, this function clears its pending status and
		462	returns its C<$revents> bitset (as if its callback was invoked). If the
		463	watcher isn't pending it does nothing and returns C<0>.
		464
		465	=item $previous_state = $w->keepalive ($bool)
		466
		467	Normally, C<EV::loop> will return when there are no active watchers
		468	(which is a "deadlock" because no progress can be made anymore). This is
		469	convenient because it allows you to start your watchers (and your jobs),
		470	call C<EV::loop> once and when it returns you know that all your jobs are
		471	finished (or they forgot to register some watchers for their task :).
		472
		473	Sometimes, however, this gets in your way, for example when the module
		474	that calls C<EV::loop> (usually the main program) is not the same module
		475	as a long-living watcher (for example a DNS client module written by
		476	somebody else even). Then you might want any outstanding requests to be
		477	handled, but you would not want to keep C<EV::loop> from returning just
		478	because you happen to have this long-running UDP port watcher.
		479
		480	In this case you can clear the keepalive status, which means that even
		481	though your watcher is active, it won't keep C<EV::loop> from returning.
		482
		483	The initial value for keepalive is true (enabled), and you can change it
		484	any time.
		485
		486	Example: Register an I/O watcher for some UDP socket but do not keep the
		487	event loop from running just because of that watcher.
		488
		489	my $udp_socket = ...
		490	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		491	$udp_watcher->keepalive (0);
		492
		493	=item $loop = $w->loop
		494
		495	Return the loop that this watcher is attached to.
		496
		497	=back
		498
		499
		500	=head1 WATCHER TYPES
		501
		502	Each of the following subsections describes a single watcher type.
		503
		504	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		505
		506	=over 4
		507
127	=item my $w = EV::io $fileno_or_fh, $eventmask, $callback	508	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
128		509
129	=item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	510	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		511
		512	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		513
		514	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
130		515
131	As long as the returned watcher object is alive, call the C<$callback>	516	As long as the returned watcher object is alive, call the C<$callback>
132	when the events specified in C<$eventmask> happen. Initially, the timeout	517	when at least one of events specified in C<$eventmask> occurs.
133	is disabled.
134		518
135	You can additionall set a timeout to occur on the watcher, but note that
136	this timeout will not be reset when you get an I/O event in the EV::PERSIST
137	case, and reaching a timeout will always stop the watcher even in the
138	EV::PERSIST case.
139
140	If you want a timeout to occur only after a specific time of inactivity, set
141	a repeating timeout and do NOT use EV::PERSIST.
142
143	Eventmask can be one or more of these constants ORed together:	519	The $eventmask can be one or more of these constants ORed together:
144		520
145	EV::READ wait until read() wouldn't block anymore	521	EV::READ wait until read() wouldn't block anymore
146	EV::WRITE wait until write() wouldn't block anymore	522	EV::WRITE wait until write() wouldn't block anymore
147	EV::PERSIST stay active after a (non-timeout) event occured
148		523
149	The C<io_ns> variant doesn't add/start the newly created watcher.	524	The C<io_ns> variant doesn't start (activate) the newly created watcher.
150		525
151	=item my $w = EV::timed_io $fileno_or_fh, $eventmask, $timeout, $callback	526	=item $w->set ($fileno_or_fh, $eventmask)
152		527
153	=item my $w = EV::timed_io_ns $fileno_or_fh, $eventmask, $timeout, $callback	528	Reconfigures the watcher, see the constructor above for details. Can be
		529	called at any time.
154		530
155	Same as C<io> and C<io_ns>, but also specifies a timeout (as if there was	531	=item $current_fh = $w->fh
156	a call to C<< $w->timeout ($timout, 1) >>. The persist flag is not allowed
157	and will automatically be cleared. The watcher will be restarted after each event.
158		532
159	If the timeout is zero or undef, no timeout will be set, and a normal	533	=item $old_fh = $w->fh ($new_fh)
160	watcher (with the persist flag set!) will be created.
161		534
162	This has the effect of timing out after the specified period of inactivity	535	Returns the previously set filehandle and optionally set a new one.
163	has happened.
164		536
165	Due to the design of libevent, this is also relatively inefficient, having	537	=item $current_eventmask = $w->events
166	one or two io watchers and a separate timeout watcher that you reset on
167	activity (by calling its C<start> method) is usually more efficient.
168		538
		539	=item $old_eventmask = $w->events ($new_eventmask)
		540
		541	Returns the previously set event mask and optionally set a new one.
		542
		543	=back
		544
		545
		546	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		547
		548	=over 4
		549
169	=item my $w = EV::timer $after, $repeat, $callback	550	=item $w = EV::timer $after, $repeat, $callback
170		551
171	=item my $w = EV::timer_ns $after, $repeat, $callback	552	=item $w = EV::timer_ns $after, $repeat, $callback
172		553
173	Calls the callback after C<$after> seconds. If C<$repeat> is true, the	554	=item $w = $loop->timer ($after, $repeat, $callback)
174	timer will be restarted after the callback returns. This means that the
175	callback would be called roughly every C<$after> seconds, prolonged by the
176	time the callback takes.
177		555
		556	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		557
		558	Calls the callback after C<$after> seconds (which may be fractional). If
		559	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		560	value as $after) after the callback returns.
		561
		562	This means that the callback would be called roughly after C<$after>
		563	seconds, and then every C<$repeat> seconds. The timer does his best not
		564	to drift, but it will not invoke the timer more often then once per event
		565	loop iteration, and might drift in other cases. If that isn't acceptable,
		566	look at EV::periodic, which can provide long-term stable timers.
		567
		568	The timer is based on a monotonic clock, that is, if somebody is sitting
		569	in front of the machine while the timer is running and changes the system
		570	clock, the timer will nevertheless run (roughly) the same time.
		571
178	The C<timer_ns> variant doesn't add/start the newly created watcher.	572	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
179		573
180	=item my $w = EV::timer_abs $at, $interval, $callback	574	=item $w->set ($after, $repeat)
181		575
182	=item my $w = EV::timer_abs_ns $at, $interval, $callback	576	Reconfigures the watcher, see the constructor above for details. Can be called at
		577	any time.
183		578
184	Similar to EV::timer, but the time is given as an absolute point in time	579	=item $w->again
185	(C<$at>), plus an optional C<$interval>.
186		580
187	If the C<$interval> is zero, then the callback will be called at the time	581	Similar to the C<start> method, but has special semantics for repeating timers:
188	C<$at> if that is in the future, or as soon as possible if its in the
189	past. It will not automatically repeat.
190		582
191	If the C<$interval> is nonzero, then the watcher will always be scheduled	583	If the timer is active and non-repeating, it will be stopped.
192	to time out at the next C<$at + integer * $interval> time.
193		584
194	This can be used to schedule a callback to run at very regular intervals,	585	If the timer is active and repeating, reset the timeout to occur
195	as long as the processing time is less then the interval (otherwise	586	C<$repeat> seconds after now.
196	obviously events will be skipped).	587
		588	If the timer is inactive and repeating, start it using the repeat value.
		589
		590	Otherwise do nothing.
		591
		592	This behaviour is useful when you have a timeout for some IO
		593	operation. You create a timer object with the same value for C<$after> and
		594	C<$repeat>, and then, in the read/write watcher, run the C<again> method
		595	on the timeout.
		596
		597	=back
		598
		599
		600	=head3 PERIODIC WATCHERS - to cron or not to cron?
		601
		602	=over 4
		603
		604	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
		605
		606	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		607
		608	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		609
		610	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
		611
		612	Similar to EV::timer, but is not based on relative timeouts but on
		613	absolute times. Apart from creating "simple" timers that trigger "at" the
		614	specified time, it can also be used for non-drifting absolute timers and
		615	more complex, cron-like, setups that are not adversely affected by time
		616	jumps (i.e. when the system clock is changed by explicit date -s or other
		617	means such as ntpd). It is also the most complex watcher type in EV.
		618
		619	It has three distinct "modes":
		620
		621	=over 4
		622
		623	=item * absolute timer ($interval = $reschedule_cb = 0)
		624
		625	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		626	will not adjust when a time jump occurs, that is, if it is to be run
		627	at January 1st 2011 then it will run when the system time reaches or
		628	surpasses this time.
		629
		630	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
		631
		632	In this mode the watcher will always be scheduled to time out at the
		633	next C<$at + N * $interval> time (for some integer N) and then repeat,
		634	regardless of any time jumps.
		635
		636	This can be used to create timers that do not drift with respect to system
		637	time:
		638
		639	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		640
		641	That doesn't mean there will always be 3600 seconds in between triggers,
		642	but only that the the clalback will be called when the system time shows a
		643	full hour (UTC).
197		644
198	Another way to think about it (for the mathematically inclined) is that	645	Another way to think about it (for the mathematically inclined) is that
199	C<timer_abs> will try to tun the callback at the next possible time where	646	EV::periodic will try to run the callback in this mode at the next
200	C<$time = $at (mod $interval)>, regardless of any time jumps.	647	possible time where C<$time = $at (mod $interval)>, regardless of any time
		648	jumps.
201		649
		650	=item * manual reschedule mode ($reschedule_cb = coderef)
		651
		652	In this mode $interval and $at are both being ignored. Instead, each
		653	time the periodic watcher gets scheduled, the reschedule callback
		654	($reschedule_cb) will be called with the watcher as first, and the current
		655	time as second argument.
		656
		657	I<This callback MUST NOT stop or destroy this or any other periodic
		658	watcher, ever, and MUST NOT call any event loop functions or methods>. If
		659	you need to stop it, return 1e30 and stop it afterwards. You may create
		660	and start a C<EV::prepare> watcher for this task.
		661
		662	It must return the next time to trigger, based on the passed time value
		663	(that is, the lowest time value larger than or equal to to the second
		664	argument). It will usually be called just before the callback will be
		665	triggered, but might be called at other times, too.
		666
		667	This can be used to create very complex timers, such as a timer that
		668	triggers on each midnight, local time (actually 24 hours after the last
		669	midnight, to keep the example simple. If you know a way to do it correctly
		670	in about the same space (without requiring elaborate modules), drop me a
		671	note :):
		672
		673	my $daily = EV::periodic 0, 0, sub {
		674	my ($w, $now) = @_;
		675
		676	use Time::Local ();
		677	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		678	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		679	}, sub {
		680	print "it's midnight or likely shortly after, now\n";
		681	};
		682
		683	=back
		684
202	The C<timer_abs_ns> variant doesn't add/start the newly created watcher.	685	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
203		686
		687	=item $w->set ($at, $interval, $reschedule_cb)
		688
		689	Reconfigures the watcher, see the constructor above for details. Can be called at
		690	any time.
		691
		692	=item $w->again
		693
		694	Simply stops and starts the watcher again.
		695
		696	=item $time = $w->at
		697
		698	Return the time that the watcher is expected to trigger next.
		699
		700	=back
		701
		702
		703	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		704
		705	=over 4
		706
204	=item my $w = EV::signal $signal, $callback	707	=item $w = EV::signal $signal, $callback
205		708
206	=item my $w = EV::signal_ns $signal, $callback	709	=item $w = EV::signal_ns $signal, $callback
207		710
		711	=item $w = $loop->signal ($signal, $callback)
		712
		713	=item $w = $loop->signal_ns ($signal, $callback)
		714
208	Call the callback when $signal is received (the signal can be specified	715	Call the callback when $signal is received (the signal can be specified by
209	by number or by name, just as with kill or %SIG). Signal watchers are	716	number or by name, just as with C<kill> or C<%SIG>).
210	persistent no natter what.	717
		718	Only one event loop can grab a given signal - attempting to grab the same
		719	signal from two EV loops will crash the program immediately or cause data
		720	corruption.
211		721
212	EV will grab the signal for the process (the kernel only allows one	722	EV will grab the signal for the process (the kernel only allows one
213	component to receive signals) when you start a signal watcher, and	723	component to receive a signal at a time) when you start a signal watcher,
214	removes it again when you stop it. Pelr does the same when you add/remove	724	and removes it again when you stop it. Perl does the same when you
215	callbacks to %SIG, so watch out.	725	add/remove callbacks to C<%SIG>, so watch out.
216		726
217	Unfortunately, only one handler can be registered per signal. Screw	727	You can have as many signal watchers per signal as you want.
218	libevent.
219		728
220	The C<signal_ns> variant doesn't add/start the newly created watcher.	729	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
221		730
222	=back	731	=item $w->set ($signal)
223		732
224	=head1 THE EV::Event CLASS	733	Reconfigures the watcher, see the constructor above for details. Can be
		734	called at any time.
225		735
226	All EV functions creating an event watcher (designated by C<my $w =>
227	above) support the following methods on the returned watcher object:
228
229	=over 4
230
231	=item $w->add ($timeout)
232
233	Stops and (re-)starts the event watcher, setting the optional timeout to
234	the given value, or clearing the timeout if none is given.
235
236	=item $w->start
237
238	Stops and (re-)starts the event watcher without touching the timeout.
239
240	=item $w->del
241
242	=item $w->stop
243
244	Stop the event watcher if it was started.
245
246	=item $current_callback = $w->cb
247
248	=item $old_callback = $w->cb ($new_callback)
249
250	Return the previously set callback and optionally set a new one.
251
252	=item $current_fh = $w->fh
253
254	=item $old_fh = $w->fh ($new_fh)
255
256	Returns the previously set filehandle and optionally set a new one (also
257	clears the EV::SIGNAL flag when setting a filehandle).
258
259	=item $current_signal = $w->signal	736	=item $current_signum = $w->signal
260		737
261	=item $old_signal = $w->signal ($new_signal)	738	=item $old_signum = $w->signal ($new_signal)
262		739
		740	Returns the previously set signal (always as a number not name) and
		741	optionally set a new one.
		742
		743	=back
		744
		745
		746	=head3 CHILD WATCHERS - watch out for process status changes
		747
		748	=over 4
		749
		750	=item $w = EV::child $pid, $trace, $callback
		751
		752	=item $w = EV::child_ns $pid, $trace, $callback
		753
		754	=item $w = $loop->child ($pid, $trace, $callback)
		755
		756	=item $w = $loop->child_ns ($pid, $trace, $callback)
		757
		758	Call the callback when a status change for pid C<$pid> (or any pid
		759	if C<$pid> is 0) has been received (a status change happens when the
		760	process terminates or is killed, or, when trace is true, additionally when
		761	it is stopped or continued). More precisely: when the process receives
		762	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
		763	changed/zombie children and call the callback.
		764
		765	It is valid (and fully supported) to install a child watcher after a child
		766	has exited but before the event loop has started its next iteration (for
		767	example, first you C<fork>, then the new child process might exit, and
		768	only then do you install a child watcher in the parent for the new pid).
		769
		770	You can access both exit (or tracing) status and pid by using the
		771	C<rstatus> and C<rpid> methods on the watcher object.
		772
		773	You can have as many pid watchers per pid as you want, they will all be
		774	called.
		775
		776	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		777
		778	=item $w->set ($pid, $trace)
		779
		780	Reconfigures the watcher, see the constructor above for details. Can be called at
		781	any time.
		782
		783	=item $current_pid = $w->pid
		784
263	Returns the previously set signal number and optionally set a new one (also sets	785	Returns the previously set process id and optionally set a new one.
264	the EV::SIGNAL flag when setting a signal).
265		786
266	=item $current_eventmask = $w->events	787	=item $exit_status = $w->rstatus
267		788
268	=item $old_eventmask = $w->events ($new_eventmask)	789	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		790	in perlfunc).
269		791
		792	=item $pid = $w->rpid
		793
		794	Return the pid of the awaited child (useful when you have installed a
		795	watcher for all pids).
		796
		797	=back
		798
		799
		800	=head3 STAT WATCHERS - did the file attributes just change?
		801
		802	=over 4
		803
		804	=item $w = EV::stat $path, $interval, $callback
		805
		806	=item $w = EV::stat_ns $path, $interval, $callback
		807
		808	=item $w = $loop->stat ($path, $interval, $callback)
		809
		810	=item $w = $loop->stat_ns ($path, $interval, $callback)
		811
		812	Call the callback when a file status change has been detected on
		813	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		814	to "path does not exist" is a status change like any other.
		815
		816	The C<$interval> is a recommended polling interval for systems where
		817	OS-supported change notifications don't exist or are not supported. If
		818	you use C<0> then an unspecified default is used (which is highly
		819	recommended!), which is to be expected to be around five seconds usually.
		820
		821	This watcher type is not meant for massive numbers of stat watchers,
		822	as even with OS-supported change notifications, this can be
		823	resource-intensive.
		824
		825	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		826
		827	=item ... = $w->stat
		828
		829	This call is very similar to the perl C<stat> built-in: It stats (using
		830	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		831	well as EV's idea of the current stat values) to the values found.
		832
		833	In scalar context, a boolean is return indicating success or failure of
		834	the stat. In list context, the same 13-value list as with stat is returned
		835	(except that the blksize and blocks fields are not reliable).
		836
		837	In the case of an error, errno is set to C<ENOENT> (regardless of the
		838	actual error value) and the C<nlink> value is forced to zero (if the stat
		839	was successful then nlink is guaranteed to be non-zero).
		840
		841	See also the next two entries for more info.
		842
		843	=item ... = $w->attr
		844
		845	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		846	the values most recently detected by EV. See the next entry for more info.
		847
		848	=item ... = $w->prev
		849
		850	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		851	the previous set of values, before the change.
		852
		853	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		854	to the values found I<before> a change was detected, while C<< $w->attr >>
		855	returns the values found leading to the change detection. The difference (if any)
		856	between C<prev> and C<attr> is what triggered the callback.
		857
		858	If you did something to the filesystem object and do not want to trigger
		859	yet another change, you can call C<stat> to update EV's idea of what the
		860	current attributes are.
		861
		862	=item $w->set ($path, $interval)
		863
		864	Reconfigures the watcher, see the constructor above for details. Can be
		865	called at any time.
		866
		867	=item $current_path = $w->path
		868
		869	=item $old_path = $w->path ($new_path)
		870
270	Returns the previously set event mask and optionally set a new one.	871	Returns the previously set path and optionally set a new one.
271		872
272	=item $w->timeout ($after, $repeat)	873	=item $current_interval = $w->interval
273		874
274	Resets the timeout (see C<EV::timer> for details).	875	=item $old_interval = $w->interval ($new_interval)
275		876
276	=item $w->timeout_abs ($at, $interval)	877	Returns the previously set interval and optionally set a new one. Can be
		878	used to query the actual interval used.
277		879
278	Resets the timeout (see C<EV::timer_abs> for details).
279
280	=item $w->priority_set ($priority)
281
282	Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI).
283
284	=back	880	=back
285		881
286	=head1 BUGS
287		882
288	Lots. Libevent itself isn't well tested and rather buggy, and this module	883	=head3 IDLE WATCHERS - when you've got nothing better to do...
289	is quite new at the moment.
290		884
291	Please note that the epoll method is not, in general, reliable in programs	885	=over 4
292	that use fork (even if no libveent calls are being made in the forked
293	process). If your program behaves erratically, try setting the environment
294	variable C<EVENT_NOEPOLL> first when running the program.
295		886
296	In general, if you fork, then you can only use the EV module in one of the	887	=item $w = EV::idle $callback
297	children.	888
		889	=item $w = EV::idle_ns $callback
		890
		891	=item $w = $loop->idle ($callback)
		892
		893	=item $w = $loop->idle_ns ($callback)
		894
		895	Call the callback when there are no other pending watchers of the same or
		896	higher priority (excluding check, prepare and other idle watchers of the
		897	same or lower priority, of course). They are called idle watchers because
		898	when the watcher is the highest priority pending event in the process, the
		899	process is considered to be idle at that priority.
		900
		901	If you want a watcher that is only ever called when I<no> other events are
		902	outstanding you have to set the priority to C<EV::MINPRI>.
		903
		904	The process will not block as long as any idle watchers are active, and
		905	they will be called repeatedly until stopped.
		906
		907	For example, if you have idle watchers at priority C<0> and C<1>, and
		908	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		909	and the I/O watcher will always run when ready. Only when the idle watcher
		910	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		911	pending with the C<0>-priority idle watcher be invoked.
		912
		913	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
		914
		915	=back
		916
		917
		918	=head3 PREPARE WATCHERS - customise your event loop!
		919
		920	=over 4
		921
		922	=item $w = EV::prepare $callback
		923
		924	=item $w = EV::prepare_ns $callback
		925
		926	=item $w = $loop->prepare ($callback)
		927
		928	=item $w = $loop->prepare_ns ($callback)
		929
		930	Call the callback just before the process would block. You can still
		931	create/modify any watchers at this point.
		932
		933	See the EV::check watcher, below, for explanations and an example.
		934
		935	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
		936
		937	=back
		938
		939
		940	=head3 CHECK WATCHERS - customise your event loop even more!
		941
		942	=over 4
		943
		944	=item $w = EV::check $callback
		945
		946	=item $w = EV::check_ns $callback
		947
		948	=item $w = $loop->check ($callback)
		949
		950	=item $w = $loop->check_ns ($callback)
		951
		952	Call the callback just after the process wakes up again (after it has
		953	gathered events), but before any other callbacks have been invoked.
		954
		955	This is used to integrate other event-based software into the EV
		956	mainloop: You register a prepare callback and in there, you create io and
		957	timer watchers as required by the other software. Here is a real-world
		958	example of integrating Net::SNMP (with some details left out):
		959
		960	our @snmp_watcher;
		961
		962	our $snmp_prepare = EV::prepare sub {
		963	# do nothing unless active
		964	$dispatcher->{_event_queue_h}
		965	or return;
		966
		967	# make the dispatcher handle any outstanding stuff
		968	... not shown
		969
		970	# create an I/O watcher for each and every socket
		971	@snmp_watcher = (
		972	(map { EV::io $_, EV::READ, sub { } }
		973	keys %{ $dispatcher->{_descriptors} }),
		974
		975	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		976	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		977	0, sub { },
		978	);
		979	};
		980
		981	The callbacks are irrelevant (and are not even being called), the
		982	only purpose of those watchers is to wake up the process as soon as
		983	one of those events occurs (socket readable, or timer timed out). The
		984	corresponding EV::check watcher will then clean up:
		985
		986	our $snmp_check = EV::check sub {
		987	# destroy all watchers
		988	@snmp_watcher = ();
		989
		990	# make the dispatcher handle any new stuff
		991	... not shown
		992	};
		993
		994	The callbacks of the created watchers will not be called as the watchers
		995	are destroyed before this can happen (remember EV::check gets called
		996	first).
		997
		998	The C<check_ns> variant doesn't start (activate) the newly created watcher.
		999
		1000	=back
		1001
		1002
		1003	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		1004
		1005	Fork watchers are called when a C<fork ()> was detected. The invocation
		1006	is done before the event loop blocks next and before C<check> watchers
		1007	are being called, and only in the child after the fork.
		1008
		1009	=over 4
		1010
		1011	=item $w = EV::fork $callback
		1012
		1013	=item $w = EV::fork_ns $callback
		1014
		1015	=item $w = $loop->fork ($callback)
		1016
		1017	=item $w = $loop->fork_ns ($callback)
		1018
		1019	Call the callback before the event loop is resumed in the child process
		1020	after a fork.
		1021
		1022	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		1023
		1024	=back
		1025
		1026
		1027	=head3 EMBED WATCHERS - when one backend isn't enough...
		1028
		1029	This is a rather advanced watcher type that lets you embed one event loop
		1030	into another (currently only IO events are supported in the embedded
		1031	loop, other types of watchers might be handled in a delayed or incorrect
		1032	fashion and must not be used).
		1033
		1034	See the libev documentation at
		1035	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1036	(locally installed as F<EV::libev>) for more details.
		1037
		1038	In short, this watcher is most useful on BSD systems without working
		1039	kqueue to still be able to handle a large number of sockets:
		1040
		1041	my $socket_loop;
		1042
		1043	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1044	if (
		1045	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1046	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1047	) {
		1048	# use kqueue for sockets
		1049	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1050	}
		1051
		1052	# use the default loop otherwise
		1053	$socket_loop \|\|= EV::default_loop;
		1054
		1055	=over 4
		1056
		1057	=item $w = EV::embed $otherloop[, $callback]
		1058
		1059	=item $w = EV::embed_ns $otherloop[, $callback]
		1060
		1061	=item $w = $loop->embed ($otherloop[, $callback])
		1062
		1063	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1064
		1065	Call the callback when the embedded event loop (C<$otherloop>) has any
		1066	I/O activity. The C<$callback> is optional: if it is missing, then the
		1067	embedded event loop will be managed automatically (which is recommended),
		1068	otherwise you have to invoke C<sweep> yourself.
		1069
		1070	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1071
		1072	=back
		1073
		1074	=head3 ASYNC WATCHERS - how to wake up another event loop
		1075
		1076	Async watchers are provided by EV, but have little use in perl directly,
		1077	as perl neither supports threads running in parallel nor direct access to
		1078	signal handlers or other contexts where they could be of value.
		1079
		1080	It is, however, possible to use them from the XS level.
		1081
		1082	Please see the libev documentation for further details.
		1083
		1084	=over 4
		1085
		1086	=item $w = EV::async $callback
		1087
		1088	=item $w = EV::async_ns $callback
		1089
		1090	=item $w->send
		1091
		1092	=item $bool = $w->async_pending
		1093
		1094	=back
		1095
		1096
		1097	=head1 PERL SIGNALS
		1098
		1099	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1100	with EV is as the same as any other C library: Perl-signals will only be
		1101	handled when Perl runs, which means your signal handler might be invoked
		1102	only the next time an event callback is invoked.
		1103
		1104	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1105	ensure proper operations with regards to other event watchers.
		1106
		1107	If you cannot do this for whatever reason, you can also force a watcher
		1108	to be called on every event loop iteration by installing a C<EV::check>
		1109	watcher:
		1110
		1111	my $async_check = EV::check sub { };
		1112
		1113	This ensures that perl gets into control for a short time to handle any
		1114	pending signals, and also ensures (slightly) slower overall operation.
		1115
		1116	=head1 ITHREADS
		1117
		1118	Ithreads are not supported by this module in any way. Perl pseudo-threads
		1119	is evil stuff and must die. Real threads as provided by Coro are fully
		1120	supported (and enhanced support is available via L<Coro::EV>).
		1121
		1122	=head1 FORK
		1123
		1124	Most of the "improved" event delivering mechanisms of modern operating
		1125	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1126	not supported and usually destructive). Libev makes it possible to work
		1127	around this by having a function that recreates the kernel state after
		1128	fork in the child.
		1129
		1130	On non-win32 platforms, this module requires the pthread_atfork
		1131	functionality to do this automatically for you. This function is quite
		1132	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1133	negligible, because everything the function currently does is set a flag
		1134	that is checked only when the event loop gets used the next time, so when
		1135	you do fork but not use EV, the overhead is minimal.
		1136
		1137	On win32, there is no notion of fork so all this doesn't apply, of course.
298		1138
299	=cut	1139	=cut
300		1140
301	our $DIED = sub {	1141	our $DIED = sub {
302	warn "EV: error in callback (ignoring): $@";	1142	warn "EV: error in callback (ignoring): $@";
303	};	1143	};
304		1144
305	our $NPRI = 4;	1145	default_loop
306	our $BASE = init;	1146	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
307	priority_init $NPRI;
308
309	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
310		1147
311	1;	1148	1;
312		1149
313	=head1 SEE ALSO	1150	=head1 SEE ALSO
314		1151
315	L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>.	1152	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
316	L<EV::AnyEvent>.	1153	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1154	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1155	event-loop agnostic and portable event driven programming.
317		1156
318	=head1 AUTHOR	1157	=head1 AUTHOR
319		1158
320	Marc Lehmann <schmorp@schmorp.de>	1159	Marc Lehmann <schmorp@schmorp.de>
321	http://home.schmorp.de/	1160	http://home.schmorp.de/
322		1161
323	=cut	1162	=cut
324		1163

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Comparing EV/EV.pm (file contents): Revision 1.11 by root, Mon Oct 29 07:56:03 2007 UTC vs. Revision 1.127 by root, Sun Mar 28 15:48:21 2010 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.11 by root, Mon Oct 29 07:56:03 2007 UTC vs.
Revision 1.127 by root, Sun Mar 28 15:48:21 2010 UTC