[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 1.126 by root, Tue Mar 16 17:11:48 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
63		55
64	=head1 DESCRIPTION	56	=head1 DESCRIPTION
65		57
66	This module provides an interface to libevent	58	This module provides an interface to libev
67	(L<http://monkey.org/~provos/libevent/>). You probably should acquaint	59	(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	60	below is comprehensive, one might also consult the documentation of
69	module fully.	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.
70		66
71	Please note thta this module disables the libevent EPOLL method by	67	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.	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.
73		76
74	=cut	77	=cut
75		78
76	package EV;	79	package EV;
77		80
78	use strict;	81	use common::sense;
79		82
80	BEGIN {	83	BEGIN {
81	our $VERSION = '0.02';	84	our $VERSION = '4.00';
82	use XSLoader;	85	use XSLoader;
83	XSLoader::load "EV", $VERSION;	86	XSLoader::load "EV", $VERSION;
84	}	87	}
85		88
		89	@EV::IO::ISA =
		90	@EV::Timer::ISA =
		91	@EV::Periodic::ISA =
		92	@EV::Signal::ISA =
		93	@EV::Child::ISA =
		94	@EV::Stat::ISA =
		95	@EV::Idle::ISA =
		96	@EV::Prepare::ISA =
		97	@EV::Check::ISA =
		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
		167
86	=head1 BASIC INTERFACE	168	=head1 BASIC INTERFACE
87		169
88	=over 4	170	=over 4
89		171
90	=item $EV::NPRI
91
92	How many priority levels are available.
93
94	=item $EV::DIED	172	=item $EV::DIED
95		173
96	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
97	throws an exception (with $@ containing thr error). The default prints an	175	throws an exception (with $@ containing the error). The default prints an
98	informative message and continues.	176	informative message and continues.
99		177
100	If this callback throws an exception it will be silently ignored.	178	If this callback throws an exception it will be silently ignored.
101		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
		194	=item $time = EV::time
		195
		196	Returns the current time in (fractional) seconds since the epoch.
		197
102	=item $time = EV::now	198	=item $time = EV::now
103		199
104	Returns the time in (fractional) seconds since the epoch.	200	=item $time = $loop->now
105		201
106	=item $version = EV::version	202	Returns the time the last event loop iteration has been started. This
		203	is the time that (relative) timers are based on, and referring to it is
		204	usually faster then calling EV::time.
107		205
108	=item $method = EV::method	206	=item EV::now_update
109		207
110	Return version string and event polling method used.	208	=item $loop->now_update
111		209
112	=item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT	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>.
113		213
114	=item EV::loopexit $after	214	This function is rarely useful, but when some event callback runs for a
		215	very long time without entering the event loop, updating libev's idea of
		216	the current time is a good idea.
115		217
116	Exit any active loop or dispatch after C<$after> seconds or immediately if	218	=item EV::suspend
117	C<$after> is missing or zero.
118		219
119	=item EV::dispatch	220	=item $loop->suspend
120		221
121	Same as C<EV::loop 0>.	222	=item EV::resume
122		223
123	=item EV::event $callback	224	=item $loop->resume
124		225
125	Creates a new event watcher waiting for nothing, calling the given callback.	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.
126		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 = $loop->backend
		251
		252	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
		253	or EV::BACKEND_EPOLL).
		254
		255	=item EV::loop [$flags]
		256
		257	=item $loop->loop ([$flags])
		258
		259	Begin checking for events and calling callbacks. It returns when a
		260	callback calls EV::unloop.
		261
		262	The $flags argument can be one of the following:
		263
		264	0 as above
		265	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
		266	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
		267
		268	=item EV::unloop [$how]
		269
		270	=item $loop->unloop ([$how])
		271
		272	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
		273	innermost call to EV::loop return.
		274
		275	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
		276	fast as possible.
		277
		278	=item $count = EV::loop_count
		279
		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
		352
		353	A watcher is an object that gets created to record your interest in some
		354	event. For instance, if you want to wait for STDIN to become readable, you
		355	would create an EV::io watcher for that:
		356
		357	my $watcher = EV::io *STDIN, EV::READ, sub {
		358	my ($watcher, $revents) = @_;
		359	warn "yeah, STDIN should now be readable without blocking!\n"
		360	};
		361
		362	All watchers can be active (waiting for events) or inactive (paused). Only
		363	active watchers will have their callbacks invoked. All callbacks will be
		364	called with at least two arguments: the watcher and a bitmask of received
		365	events.
		366
		367	Each watcher type has its associated bit in revents, so you can use the
		368	same callback for multiple watchers. The event mask is named after the
		369	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
		370	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
		371	(which can set both EV::READ and EV::WRITE bits).
		372
		373	In the rare case where one wants to create a watcher but not start it at
		374	the same time, each constructor has a variant with a trailing C<_ns> in
		375	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
		376
		377	Please note that a watcher will automatically be stopped when the watcher
		378	object is destroyed, so you I<need> to keep the watcher objects returned by
		379	the constructors.
		380
		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.
		384
		385	=head2 COMMON WATCHER METHODS
		386
		387	This section lists methods common to all watchers.
		388
		389	=over 4
		390
		391	=item $w->start
		392
		393	Starts a watcher if it isn't active already. Does nothing to an already
		394	active watcher. By default, all watchers start out in the active state
		395	(see the description of the C<_ns> variants if you need stopped watchers).
		396
		397	=item $w->stop
		398
		399	Stop a watcher if it is active. Also clear any pending events (events that
		400	have been received but that didn't yet result in a callback invocation),
		401	regardless of whether the watcher was active or not.
		402
		403	=item $bool = $w->is_active
		404
		405	Returns true if the watcher is active, false otherwise.
		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
		419	=item $current_cb = $w->cb
		420
		421	=item $old_cb = $w->cb ($new_cb)
		422
		423	Queries the callback on the watcher and optionally changes it. You can do
		424	this at any time without the watcher restarting.
		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
		441	=item $w->invoke ($revents)
		442
		443	Call the callback now with the given event mask.
		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
		498
127	=item my $w = EV::io $fileno_or_fh, $eventmask, $callback	499	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
128		500
129	=item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	501	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		502
		503	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		504
		505	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
130		506
131	As long as the returned watcher object is alive, call the C<$callback>	507	As long as the returned watcher object is alive, call the C<$callback>
132	when the events specified in C<$eventmask> happen. Initially, the timeout	508	when at least one of events specified in C<$eventmask> occurs.
133	is disabled.
134		509
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:	510	The $eventmask can be one or more of these constants ORed together:
144		511
145	EV::READ wait until read() wouldn't block anymore	512	EV::READ wait until read() wouldn't block anymore
146	EV::WRITE wait until write() wouldn't block anymore	513	EV::WRITE wait until write() wouldn't block anymore
147	EV::PERSIST stay active after a (non-timeout) event occured
148		514
149	The C<io_ns> variant doesn't add/start the newly created watcher.	515	The C<io_ns> variant doesn't start (activate) the newly created watcher.
150		516
151	=item my $w = EV::timed_io $fileno_or_fh, $eventmask, $timeout, $callback	517	=item $w->set ($fileno_or_fh, $eventmask)
152		518
153	=item my $w = EV::timed_io_ns $fileno_or_fh, $eventmask, $timeout, $callback	519	Reconfigures the watcher, see the constructor above for details. Can be
		520	called at any time.
154		521
155	Same as C<io> and C<io_ns>, but also specifies a timeout (as if there was	522	=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		523
159	If the timeout is zero or undef, no timeout will be set, and a normal	524	=item $old_fh = $w->fh ($new_fh)
160	watcher (with the persist flag set!) will be created.
161		525
162	This has the effect of timing out after the specified period of inactivity	526	Returns the previously set filehandle and optionally set a new one.
163	has happened.
164		527
165	Due to the design of libevent, this is also relatively inefficient, having	528	=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		529
		530	=item $old_eventmask = $w->events ($new_eventmask)
		531
		532	Returns the previously set event mask and optionally set a new one.
		533
		534	=back
		535
		536
		537	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		538
		539	=over 4
		540
169	=item my $w = EV::timer $after, $repeat, $callback	541	=item $w = EV::timer $after, $repeat, $callback
170		542
171	=item my $w = EV::timer_ns $after, $repeat, $callback	543	=item $w = EV::timer_ns $after, $repeat, $callback
172		544
173	Calls the callback after C<$after> seconds. If C<$repeat> is true, the	545	=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		546
		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 $after) after the callback returns.
		552
		553	This means that the callback would be called roughly after C<$after>
		554	seconds, and then every C<$repeat> seconds. The timer does his best not
		555	to drift, but it will not invoke the timer more often then once per event
		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.
		558
		559	The timer is based on a monotonic clock, that is, if somebody is sitting
		560	in front of the machine while the timer is running and changes the system
		561	clock, the timer will nevertheless run (roughly) the same time.
		562
178	The C<timer_ns> variant doesn't add/start the newly created watcher.	563	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
179		564
180	=item my $w = EV::timer_abs $at, $interval, $callback	565	=item $w->set ($after, $repeat)
181		566
182	=item my $w = EV::timer_abs_ns $at, $interval, $callback	567	Reconfigures the watcher, see the constructor above for details. Can be called at
		568	any time.
183		569
184	Similar to EV::timer, but the time is given as an absolute point in time	570	=item $w->again
185	(C<$at>), plus an optional C<$interval>.
186		571
187	If the C<$interval> is zero, then the callback will be called at the time	572	Similar to the C<start> method, but has special semantics for repeating timers:
188	C<$at> if that is in the future, or as soon as possible if its in the
189	past. It will not automatically repeat.
190		573
191	If the C<$interval> is nonzero, then the watcher will always be scheduled	574	If the timer is active and non-repeating, it will be stopped.
192	to time out at the next C<$at + integer * $interval> time.
193		575
194	This can be used to schedule a callback to run at very regular intervals,	576	If the timer is active and repeating, reset the timeout to occur
195	as long as the processing time is less then the interval (otherwise	577	C<$repeat> seconds after now.
196	obviously events will be skipped).	578
		579	If the timer is inactive and repeating, start it using the repeat value.
		580
		581	Otherwise do nothing.
		582
		583	This behaviour is useful when you have a timeout for some IO
		584	operation. You create a timer object with the same value for C<$after> and
		585	C<$repeat>, and then, in the read/write watcher, run the C<again> method
		586	on the timeout.
		587
		588	=back
		589
		590
		591	=head3 PERIODIC WATCHERS - to cron or not to cron?
		592
		593	=over 4
		594
		595	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
		596
		597	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		598
		599	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		600
		601	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
		602
		603	Similar to EV::timer, but is not based on relative timeouts but on
		604	absolute times. Apart from creating "simple" timers that trigger "at" the
		605	specified time, it can also be used for non-drifting absolute timers and
		606	more complex, cron-like, setups that are not adversely affected by time
		607	jumps (i.e. when the system clock is changed by explicit date -s or other
		608	means such as ntpd). It is also the most complex watcher type in EV.
		609
		610	It has three distinct "modes":
		611
		612	=over 4
		613
		614	=item * absolute timer ($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 $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		631
		632	That doesn't mean there will always be 3600 seconds in between triggers,
		633	but only that the the clalback will be called when the system time shows a
		634	full hour (UTC).
197		635
198	Another way to think about it (for the mathematically inclined) is that	636	Another way to think about it (for the mathematically inclined) is that
199	C<timer_abs> will try to tun the callback at the next possible time where	637	EV::periodic will try to run the callback in this mode at the next
200	C<$time = $at (mod $interval)>, regardless of any time jumps.	638	possible time where C<$time = $at (mod $interval)>, regardless of any time
		639	jumps.
201		640
		641	=item * manual reschedule mode ($reschedule_cb = coderef)
		642
		643	In this mode $interval and $at are both being ignored. Instead, each
		644	time the periodic watcher gets scheduled, the reschedule callback
		645	($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
		675
202	The C<timer_abs_ns> variant doesn't add/start the newly created watcher.	676	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
203		677
		678	=item $w->set ($at, $interval, $reschedule_cb)
		679
		680	Reconfigures the watcher, see the constructor above for details. Can be called at
		681	any time.
		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
		697
204	=item my $w = EV::signal $signal, $callback	698	=item $w = EV::signal $signal, $callback
205		699
206	=item my $w = EV::signal_ns $signal, $callback	700	=item $w = EV::signal_ns $signal, $callback
207		701
		702	=item $w = $loop->signal ($signal, $callback)
		703
		704	=item $w = $loop->signal_ns ($signal, $callback)
		705
208	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
209	by number or by name, just as with kill or %SIG). Signal watchers are	707	number or by name, just as with C<kill> or C<%SIG>).
210	persistent no natter what.	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.
211		712
212	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
213	component to receive signals) when you start a signal watcher, and	714	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	715	and removes it again when you stop it. Perl does the same when you
215	callbacks to %SIG, so watch out.	716	add/remove callbacks to C<%SIG>, so watch out.
216		717
217	Unfortunately, only one handler can be registered per signal. Screw	718	You can have as many signal watchers per signal as you want.
218	libevent.
219		719
220	The C<signal_ns> variant doesn't add/start the newly created watcher.	720	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
221		721
222	=back	722	=item $w->set ($signal)
223		723
224	=head1 THE EV::Event CLASS	724	Reconfigures the watcher, see the constructor above for details. Can be
		725	called at any time.
225		726
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	727	=item $current_signum = $w->signal
260		728
261	=item $old_signal = $w->signal ($new_signal)	729	=item $old_signum = $w->signal ($new_signal)
262		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
		772	any time.
		773
		774	=item $current_pid = $w->pid
		775
263	Returns the previously set signal number and optionally set a new one (also sets	776	Returns the previously set process id and optionally set a new one.
264	the EV::SIGNAL flag when setting a signal).
265		777
266	=item $current_eventmask = $w->events	778	=item $exit_status = $w->rstatus
267		779
268	=item $old_eventmask = $w->events ($new_eventmask)	780	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		781	in perlfunc).
269		782
		783	=item $pid = $w->rpid
		784
		785	Return the pid of the awaited child (useful when you have installed a
		786	watcher for all pids).
		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
		816	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		817
		818	=item ... = $w->stat
		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
		855	Reconfigures the watcher, see the constructor above for details. Can be
		856	called at any time.
		857
		858	=item $current_path = $w->path
		859
		860	=item $old_path = $w->path ($new_path)
		861
270	Returns the previously set event mask and optionally set a new one.	862	Returns the previously set path and optionally set a new one.
271		863
272	=item $w->timeout ($after, $repeat)	864	=item $current_interval = $w->interval
273		865
274	Resets the timeout (see C<EV::timer> for details).	866	=item $old_interval = $w->interval ($new_interval)
275		867
276	=item $w->timeout_abs ($at, $interval)	868	Returns the previously set interval and optionally set a new one. Can be
		869	used to query the actual interval used.
277		870
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	871	=back
285		872
286	=head1 BUGS
287		873
288	Lots. Libevent itself isn't well tested and rather buggy, and this module	874	=head3 IDLE WATCHERS - when you've got nothing better to do...
289	is quite new at the moment.
290		875
291	Please note that the epoll method is not, in general, reliable in programs	876	=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		877
296	In general, if you fork, then you can only use the EV module in one of the	878	=item $w = EV::idle $callback
297	children.	879
		880	=item $w = EV::idle_ns $callback
		881
		882	=item $w = $loop->idle ($callback)
		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>.
		894
		895	The process will not block as long as any idle watchers are active, and
		896	they will be called repeatedly until stopped.
		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
		904	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
		905
		906	=back
		907
		908
		909	=head3 PREPARE WATCHERS - customise your event loop!
		910
		911	=over 4
		912
		913	=item $w = EV::prepare $callback
		914
		915	=item $w = EV::prepare_ns $callback
		916
		917	=item $w = $loop->prepare ($callback)
		918
		919	=item $w = $loop->prepare_ns ($callback)
		920
		921	Call the callback just before the process would block. You can still
		922	create/modify any watchers at this point.
		923
		924	See the EV::check watcher, below, for explanations and an example.
		925
		926	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
		927
		928	=back
		929
		930
		931	=head3 CHECK WATCHERS - customise your event loop even more!
		932
		933	=over 4
		934
		935	=item $w = EV::check $callback
		936
		937	=item $w = EV::check_ns $callback
		938
		939	=item $w = $loop->check ($callback)
		940
		941	=item $w = $loop->check_ns ($callback)
		942
		943	Call the callback just after the process wakes up again (after it has
		944	gathered events), but before any other callbacks have been invoked.
		945
		946	This is used to integrate other event-based software into the EV
		947	mainloop: You register a prepare callback and in there, you create io and
		948	timer watchers as required by the other software. Here is a real-world
		949	example of integrating Net::SNMP (with some details left out):
		950
		951	our @snmp_watcher;
		952
		953	our $snmp_prepare = EV::prepare sub {
		954	# do nothing unless active
		955	$dispatcher->{_event_queue_h}
		956	or return;
		957
		958	# make the dispatcher handle any outstanding stuff
		959	... not shown
		960
		961	# create an I/O watcher for each and every socket
		962	@snmp_watcher = (
		963	(map { EV::io $_, EV::READ, sub { } }
		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 { },
		969	);
		970	};
		971
		972	The callbacks are irrelevant (and are not even being called), the
		973	only purpose of those watchers is to wake up the process as soon as
		974	one of those events occurs (socket readable, or timer timed out). The
		975	corresponding EV::check watcher will then clean up:
		976
		977	our $snmp_check = EV::check sub {
		978	# destroy all watchers
		979	@snmp_watcher = ();
		980
		981	# make the dispatcher handle any new stuff
		982	... not shown
		983	};
		984
		985	The callbacks of the created watchers will not be called as the watchers
		986	are destroyed before this can happen (remember EV::check gets called
		987	first).
		988
		989	The C<check_ns> variant doesn't start (activate) the newly created watcher.
		990
		991	=back
		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
		1107	=head1 ITHREADS
		1108
		1109	Ithreads are not supported by this module in any way. Perl pseudo-threads
		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.
298		1129
299	=cut	1130	=cut
300		1131
301	our $DIED = sub {	1132	our $DIED = sub {
302	warn "EV: error in callback (ignoring): $@";	1133	warn "EV: error in callback (ignoring): $@";
303	};	1134	};
304		1135
305	our $NPRI = 4;	1136	default_loop
306	our $BASE = init;	1137	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
307	priority_init $NPRI;
308
309	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
310		1138
311	1;	1139	1;
312		1140
313	=head1 SEE ALSO	1141	=head1 SEE ALSO
314		1142
315	L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>.	1143	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
316	L<EV::AnyEvent>.	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.
317		1147
318	=head1 AUTHOR	1148	=head1 AUTHOR
319		1149
320	Marc Lehmann <schmorp@schmorp.de>	1150	Marc Lehmann <schmorp@schmorp.de>
321	http://home.schmorp.de/	1151	http://home.schmorp.de/
322		1152
323	=cut	1153	=cut
324		1154

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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 1.126 by root, Tue Mar 16 17:11:48 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 1.126 by root, Tue Mar 16 17:11:48 2010 UTC