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

Comparing EV/EV.pm (file contents):
Revision 1.8 by root, Sat Oct 27 19:11:27 2007 UTC vs.
Revision 1.130 by root, Sun Oct 24 17:58:41 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		8
9	# TIMER	9	# TIMERS
10		10
11	my $w = EV::timer 2, 0, sub {	11	my $w = EV::timer 2, 0, sub {
12	warn "is called after 2s";	12	warn "is called after 2s";
13	};	13	};
14		14
15	my $w = EV::timer 2, 1, sub {	15	my $w = EV::timer 2, 2, sub {
16	warn "is called roughly every 2s (repeat = 1)";	16	warn "is called roughly every 2s (repeat = 2)";
17	};	17	};
18		18
19	undef $w; # destroy event watcher again	19	undef $w; # destroy event watcher again
20		20
21	# IO
22
23	my $w = EV::timer_abs 0, 60, sub {	21	my $w = EV::periodic 0, 60, 0, sub {
24	warn "is called every minute, on the minute, exactly";	22	warn "is called every minute, on the minute, exactly";
25	};	23	};
26		24
		25	# IO
		26
27	my $w = EV::io \*STDIN, EV::READ \| EV::PERSIST, sub {	27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $events) = @_; # all callbacks get the watcher object and event mask	28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29	if ($events & EV::TIMEOUT) {
30	warn "nothign received on stdin for 10 seconds, retrying";
31	} else {
32	warn "stdin is readable, you entered: ", <STDIN>;	29	warn "stdin is readable, you entered: ", <STDIN>;
33	}	30	};
		31
		32	# SIGNALS
		33
		34	my $w = EV::signal 'QUIT', sub {
		35	warn "sigquit received\n";
34	};	36	};
35	$w->timeout (10);	37
36		38	# CHILD/PID STATUS CHANGES
		39
		40	my $w = EV::child 666, 0, sub {
		41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
		43	};
		44
		45	# STAT CHANGES
		46	my $w = EV::stat "/etc/passwd", 10, sub {
		47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
		49	};
		50
37	# MAINLOOP	51	# MAINLOOP
38	EV::dispatch; # loop as long as watchers are active	52	EV::loop; # loop until EV::unloop is called or all watchers stop
39	EV::loop; # the same thing	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
40	EV::loop EV::LOOP_ONCE;	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
41	EV::loop EV::LOOP_ONSHOT;	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.
42		64
43	=head1 DESCRIPTION	65	=head1 DESCRIPTION
44		66
45	This module provides an interface to libevent	67	This module provides an interface to libev
46	(L<http://monkey.org/~provos/libevent/>). You probably should acquaint	68	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
47	yourself with its documentation and source code to be able to use this	69	below is comprehensive, one might also consult the documentation of
48	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.
49		75
50	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
51	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 PORTING FROM EV 3.X to 4.X
		83
		84	EV version 4 introduces a number of incompatible changes summarised
		85	here. According to the depreciation strategy used by libev, there is a
		86	compatibility layer in place so programs should continue to run unchanged
		87	(the XS interface lacks this layer, so programs using that one need to be
		88	updated).
		89
		90	This compatibility layer will be switched off in some future release.
		91
		92	All changes relevant to Perl are renames of symbols, functions and
		93	methods:
		94
		95	EV::loop => EV::run
		96	EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
		97	EV::LOOP_ONESHOT => EV::RUN_ONCE
		98
		99	EV::unloop => EV::break
		100	EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
		101	EV::UNLOOP_ONE => EV::BREAK_ONE
		102	EV::UNLOOP_ALL => EV::BREAK_ALL
		103
		104	EV::TIMEOUT => EV::TIMER
		105
		106	EV::loop_count => EV::iteration
		107	EV::loop_depth => EV::depth
		108	EV::loop_verify => EV::verify
		109
		110	The loop object methods corresponding to the functions above have been
		111	similarly renamed.
		112
		113	=head2 MODULE EXPORTS
		114
		115	This module does not export any symbols.
52		116
53	=cut	117	=cut
54		118
55	package EV;	119	package EV;
56		120
57	use strict;	121	use common::sense;
58		122
59	BEGIN {	123	BEGIN {
60	our $VERSION = '0.01';	124	our $VERSION = '4.00';
61	use XSLoader;	125	use XSLoader;
62	XSLoader::load "EV", $VERSION;	126	XSLoader::load "EV", $VERSION;
63	}	127	}
64		128
		129	@EV::IO::ISA =
		130	@EV::Timer::ISA =
		131	@EV::Periodic::ISA =
		132	@EV::Signal::ISA =
		133	@EV::Child::ISA =
		134	@EV::Stat::ISA =
		135	@EV::Idle::ISA =
		136	@EV::Prepare::ISA =
		137	@EV::Check::ISA =
		138	@EV::Embed::ISA =
		139	@EV::Fork::ISA =
		140	@EV::Async::ISA =
		141	"EV::Watcher";
		142
		143	@EV::Loop::Default::ISA = "EV::Loop";
		144
		145	=head1 EVENT LOOPS
		146
		147	EV supports multiple event loops: There is a single "default event loop"
		148	that can handle everything including signals and child watchers, and any
		149	number of "dynamic event loops" that can use different backends (with
		150	various limitations), but no child and signal watchers.
		151
		152	You do not have to do anything to create the default event loop: When
		153	the module is loaded a suitable backend is selected on the premise of
		154	selecting a working backend (which for example rules out kqueue on most
		155	BSDs). Modules should, unless they have "special needs" always use the
		156	default loop as this is fastest (perl-wise), best supported by other
		157	modules (e.g. AnyEvent or Coro) and most portable event loop.
		158
		159	For specific programs you can create additional event loops dynamically.
		160
		161	If you want to take advantage of kqueue (which often works properly for
		162	sockets only) even though the default loop doesn't enable it, you can
		163	I<embed> a kqueue loop into the default loop: running the default loop
		164	will then also service the kqueue loop to some extent. See the example in
		165	the section about embed watchers for an example on how to achieve that.
		166
		167	=over 4
		168
		169	=item $loop = new EV::Loop [$flags]
		170
		171	Create a new event loop as per the specified flags. Please refer to
		172	the C<ev_loop_new ()> function description in the libev documentation
		173	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
		174	or locally-installed as F<EV::libev> manpage) for more info.
		175
		176	The loop will automatically be destroyed when it is no longer referenced
		177	by any watcher and the loop object goes out of scope.
		178
		179	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		180	is recommended, as only the default event loop is protected by this
		181	module. If you I<are> embedding this loop in the default loop, this is not
		182	necessary, as C<EV::embed> automatically does the right thing on fork.
		183
		184	=item $loop->loop_fork
		185
		186	Must be called after a fork in the child, before entering or continuing
		187	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		188	this function automatically, at some performance loss (refer to the libev
		189	documentation).
		190
		191	=item $loop->loop_verify
		192
		193	Calls C<ev_verify> to make internal consistency checks (for debugging
		194	libev) and abort the program if any data structures were found to be
		195	corrupted.
		196
		197	=item $loop = EV::default_loop [$flags]
		198
		199	Return the default loop (which is a singleton object). Since this module
		200	already creates the default loop with default flags, specifying flags here
		201	will not have any effect unless you destroy the default loop first, which
		202	isn't supported. So in short: don't do it, and if you break it, you get to
		203	keep the pieces.
		204
		205	=back
		206
		207
65	=head1 BASIC INTERFACE	208	=head1 BASIC INTERFACE
66		209
67	=over 4	210	=over 4
68		211
69	=item $EV::NPRI
70
71	How many priority levels are available.
72
73	=item $EV::DIED	212	=item $EV::DIED
74		213
75	Must contain a reference to a function that is called when a callback	214	Must contain a reference to a function that is called when a callback
76	throws an exception (with $@ containing thr error). The default prints an	215	throws an exception (with $@ containing the error). The default prints an
77	informative message and continues.	216	informative message and continues.
78		217
79	If this callback throws an exception it will be silently ignored.	218	If this callback throws an exception it will be silently ignored.
80		219
		220	=item $flags = EV::supported_backends
		221
		222	=item $flags = EV::recommended_backends
		223
		224	=item $flags = EV::embeddable_backends
		225
		226	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		227	instance of EV, the set of recommended backends (supposed to be good) for
		228	this platform and the set of embeddable backends (see EMBED WATCHERS).
		229
		230	=item EV::sleep $seconds
		231
		232	Block the process for the given number of (fractional) seconds.
		233
		234	=item $time = EV::time
		235
		236	Returns the current time in (fractional) seconds since the epoch.
		237
81	=item $time = EV::now	238	=item $time = EV::now
82		239
83	Returns the time in (fractional) seconds since the epoch.	240	=item $time = $loop->now
84		241
85	=item $version = EV::version	242	Returns the time the last event loop iteration has been started. This
		243	is the time that (relative) timers are based on, and referring to it is
		244	usually faster then calling EV::time.
86		245
87	=item $method = EV::method	246	=item EV::now_update
88		247
89	Return version string and event polling method used.	248	=item $loop->now_update
90		249
91	=item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT	250	Establishes the current time by querying the kernel, updating the time
		251	returned by C<EV::now> in the progress. This is a costly operation and
		252	is usually done automatically within C<EV::loop>.
92		253
93	=item EV::loopexit $after	254	This function is rarely useful, but when some event callback runs for a
		255	very long time without entering the event loop, updating libev's idea of
		256	the current time is a good idea.
94		257
95	Exit any active loop or dispatch after C<$after> seconds or immediately if	258	=item EV::suspend
96	C<$after> is missing or zero.
97		259
98	=item EV::dispatch	260	=item $loop->suspend
99		261
100	Same as C<EV::loop 0>.	262	=item EV::resume
101		263
102	=item EV::event $callback	264	=item $loop->resume
103		265
104	Creates a new event watcher waiting for nothing, calling the given callback.	266	These two functions suspend and resume a loop, for use when the loop is
		267	not used for a while and timeouts should not be processed.
105		268
		269	A typical use case would be an interactive program such as a game: When
		270	the user presses C<^Z> to suspend the game and resumes it an hour later it
		271	would be best to handle timeouts as if no time had actually passed while
		272	the program was suspended. This can be achieved by calling C<suspend>
		273	in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
		274	C<resume> directly afterwards to resume timer processing.
		275
		276	Effectively, all C<timer> watchers will be delayed by the time spend
		277	between C<suspend> and C<resume>, and all C<periodic> watchers
		278	will be rescheduled (that is, they will lose any events that would have
		279	occured while suspended).
		280
		281	After calling C<suspend> you B<must not> call I<any> function on the given
		282	loop other than C<resume>, and you B<must not> call C<resume>
		283	without a previous call to C<suspend>.
		284
		285	Calling C<suspend>/C<resume> has the side effect of updating the event
		286	loop time (see C<now_update>).
		287
		288	=item $backend = EV::backend
		289
		290	=item $backend = $loop->backend
		291
		292	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
		293	or EV::BACKEND_EPOLL).
		294
		295	=item EV::loop [$flags]
		296
		297	=item $loop->loop ([$flags])
		298
		299	Begin checking for events and calling callbacks. It returns when a
		300	callback calls EV::unloop.
		301
		302	The $flags argument can be one of the following:
		303
		304	0 as above
		305	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
		306	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
		307
		308	=item EV::unloop [$how]
		309
		310	=item $loop->unloop ([$how])
		311
		312	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
		313	innermost call to EV::loop return.
		314
		315	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
		316	fast as possible.
		317
		318	=item $count = EV::loop_count
		319
		320	=item $count = $loop->loop_count
		321
		322	Return the number of times the event loop has polled for new
		323	events. Sometimes useful as a generation counter.
		324
		325	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		326
		327	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		328
		329	This function rolls together an I/O and a timer watcher for a single
		330	one-shot event without the need for managing a watcher object.
		331
		332	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		333	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		334	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		335	you do not want to wait for some I/O event, specify C<undef> for
		336	C<$fh_or_undef> and C<0> for C<$events>).
		337
		338	If timeout is C<undef> or negative, then there will be no
		339	timeout. Otherwise a EV::timer with this value will be started.
		340
		341	When an error occurs or either the timeout or I/O watcher triggers, then
		342	the callback will be called with the received event set (in general
		343	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		344	C<EV::WRITE> and C<EV::TIMER>).
		345
		346	EV::once doesn't return anything: the watchers stay active till either
		347	of them triggers, then they will be stopped and freed, and the callback
		348	invoked.
		349
		350	=item EV::feed_fd_event ($fd, $revents)
		351
		352	=item $loop->feed_fd_event ($fd, $revents)
		353
		354	Feed an event on a file descriptor into EV. EV will react to this call as
		355	if the readyness notifications specified by C<$revents> (a combination of
		356	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		357
		358	=item EV::feed_signal_event ($signal)
		359
		360	Feed a signal event into EV. EV will react to this call as if the signal
		361	specified by C<$signal> had occured.
		362
		363	=item EV::set_io_collect_interval $time
		364
		365	=item $loop->set_io_collect_interval ($time)
		366
		367	=item EV::set_timeout_collect_interval $time
		368
		369	=item $loop->set_timeout_collect_interval ($time)
		370
		371	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		372	wait interval for timer events. See the libev documentation at
		373	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		374	(locally installed as F<EV::libev>) for a more detailed discussion.
		375
		376	=item $count = EV::pending_count
		377
		378	=item $count = $loop->pending_count
		379
		380	Returns the number of currently pending watchers.
		381
		382	=item EV::invoke_pending
		383
		384	=item $loop->invoke_pending
		385
		386	Invoke all currently pending watchers.
		387
		388	=back
		389
		390
		391	=head1 WATCHER OBJECTS
		392
		393	A watcher is an object that gets created to record your interest in some
		394	event. For instance, if you want to wait for STDIN to become readable, you
		395	would create an EV::io watcher for that:
		396
		397	my $watcher = EV::io *STDIN, EV::READ, sub {
		398	my ($watcher, $revents) = @_;
		399	warn "yeah, STDIN should now be readable without blocking!\n"
		400	};
		401
		402	All watchers can be active (waiting for events) or inactive (paused). Only
		403	active watchers will have their callbacks invoked. All callbacks will be
		404	called with at least two arguments: the watcher and a bitmask of received
		405	events.
		406
		407	Each watcher type has its associated bit in revents, so you can use the
		408	same callback for multiple watchers. The event mask is named after the
		409	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
		410	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
		411	(which can set both EV::READ and EV::WRITE bits).
		412
		413	In the rare case where one wants to create a watcher but not start it at
		414	the same time, each constructor has a variant with a trailing C<_ns> in
		415	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
		416
		417	Please note that a watcher will automatically be stopped when the watcher
		418	object is destroyed, so you I<need> to keep the watcher objects returned by
		419	the constructors.
		420
		421	Also, all methods changing some aspect of a watcher (->set, ->priority,
		422	->fh and so on) automatically stop and start it again if it is active,
		423	which means pending events get lost.
		424
		425	=head2 COMMON WATCHER METHODS
		426
		427	This section lists methods common to all watchers.
		428
		429	=over 4
		430
		431	=item $w->start
		432
		433	Starts a watcher if it isn't active already. Does nothing to an already
		434	active watcher. By default, all watchers start out in the active state
		435	(see the description of the C<_ns> variants if you need stopped watchers).
		436
		437	=item $w->stop
		438
		439	Stop a watcher if it is active. Also clear any pending events (events that
		440	have been received but that didn't yet result in a callback invocation),
		441	regardless of whether the watcher was active or not.
		442
		443	=item $bool = $w->is_active
		444
		445	Returns true if the watcher is active, false otherwise.
		446
		447	=item $current_data = $w->data
		448
		449	=item $old_data = $w->data ($new_data)
		450
		451	Queries a freely usable data scalar on the watcher and optionally changes
		452	it. This is a way to associate custom data with a watcher:
		453
		454	my $w = EV::timer 60, 0, sub {
		455	warn $_[0]->data;
		456	};
		457	$w->data ("print me!");
		458
		459	=item $current_cb = $w->cb
		460
		461	=item $old_cb = $w->cb ($new_cb)
		462
		463	Queries the callback on the watcher and optionally changes it. You can do
		464	this at any time without the watcher restarting.
		465
		466	=item $current_priority = $w->priority
		467
		468	=item $old_priority = $w->priority ($new_priority)
		469
		470	Queries the priority on the watcher and optionally changes it. Pending
		471	watchers with higher priority will be invoked first. The valid range of
		472	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		473	-2). If the priority is outside this range it will automatically be
		474	normalised to the nearest valid priority.
		475
		476	The default priority of any newly-created watcher is 0.
		477
		478	Note that the priority semantics have not yet been fleshed out and are
		479	subject to almost certain change.
		480
		481	=item $w->invoke ($revents)
		482
		483	Call the callback now with the given event mask.
		484
		485	=item $w->feed_event ($revents)
		486
		487	Feed some events on this watcher into EV. EV will react to this call as if
		488	the watcher had received the given C<$revents> mask.
		489
		490	=item $revents = $w->clear_pending
		491
		492	If the watcher is pending, this function clears its pending status and
		493	returns its C<$revents> bitset (as if its callback was invoked). If the
		494	watcher isn't pending it does nothing and returns C<0>.
		495
		496	=item $previous_state = $w->keepalive ($bool)
		497
		498	Normally, C<EV::loop> will return when there are no active watchers
		499	(which is a "deadlock" because no progress can be made anymore). This is
		500	convenient because it allows you to start your watchers (and your jobs),
		501	call C<EV::loop> once and when it returns you know that all your jobs are
		502	finished (or they forgot to register some watchers for their task :).
		503
		504	Sometimes, however, this gets in your way, for example when the module
		505	that calls C<EV::loop> (usually the main program) is not the same module
		506	as a long-living watcher (for example a DNS client module written by
		507	somebody else even). Then you might want any outstanding requests to be
		508	handled, but you would not want to keep C<EV::loop> from returning just
		509	because you happen to have this long-running UDP port watcher.
		510
		511	In this case you can clear the keepalive status, which means that even
		512	though your watcher is active, it won't keep C<EV::loop> from returning.
		513
		514	The initial value for keepalive is true (enabled), and you can change it
		515	any time.
		516
		517	Example: Register an I/O watcher for some UDP socket but do not keep the
		518	event loop from running just because of that watcher.
		519
		520	my $udp_socket = ...
		521	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		522	$udp_watcher->keepalive (0);
		523
		524	=item $loop = $w->loop
		525
		526	Return the loop that this watcher is attached to.
		527
		528	=back
		529
		530
		531	=head1 WATCHER TYPES
		532
		533	Each of the following subsections describes a single watcher type.
		534
		535	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		536
		537	=over 4
		538
106	=item my $w = EV::io $fileno_or_fh, $eventmask, $callback	539	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
107		540
108	=item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	541	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		542
		543	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		544
		545	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
109		546
110	As long as the returned watcher object is alive, call the C<$callback>	547	As long as the returned watcher object is alive, call the C<$callback>
111	when the events specified in C<$eventmask> happen. Initially, the timeout	548	when at least one of events specified in C<$eventmask> occurs.
112	is disabled.
113		549
114	Youc an additionall set a timeout to occur on the watcher, but note that
115	this timeout will not be reset when you get an I/O event in the EV::PERSIST
116	case, and reaching a timeout will always stop the watcher even in the
117	EV::PERSIST case.
118
119	If you want a timeout to occur only after a specific time of inactivity, set
120	a repeating timeout and do NOT use EV::PERSIST.
121
122	Eventmask can be one or more of these constants ORed together:	550	The $eventmask can be one or more of these constants ORed together:
123		551
124	EV::READ wait until read() wouldn't block anymore	552	EV::READ wait until read() wouldn't block anymore
125	EV::WRITE wait until write() wouldn't block anymore	553	EV::WRITE wait until write() wouldn't block anymore
126	EV::PERSIST stay active after a (non-timeout) event occured
127		554
128	The C<io_ns> variant doesn't add/start the newly created watcher.	555	The C<io_ns> variant doesn't start (activate) the newly created watcher.
129		556
		557	=item $w->set ($fileno_or_fh, $eventmask)
		558
		559	Reconfigures the watcher, see the constructor above for details. Can be
		560	called at any time.
		561
		562	=item $current_fh = $w->fh
		563
		564	=item $old_fh = $w->fh ($new_fh)
		565
		566	Returns the previously set filehandle and optionally set a new one.
		567
		568	=item $current_eventmask = $w->events
		569
		570	=item $old_eventmask = $w->events ($new_eventmask)
		571
		572	Returns the previously set event mask and optionally set a new one.
		573
		574	=back
		575
		576
		577	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		578
		579	=over 4
		580
130	=item my $w = EV::timer $after, $repeat, $callback	581	=item $w = EV::timer $after, $repeat, $callback
131		582
132	=item my $w = EV::timer_ns $after, $repeat, $callback	583	=item $w = EV::timer_ns $after, $repeat, $callback
133		584
134	Calls the callback after C<$after> seconds. If C<$repeat> is true, the	585	=item $w = $loop->timer ($after, $repeat, $callback)
135	timer will be restarted after the callback returns. This means that the
136	callback would be called roughly every C<$after> seconds, prolonged by the
137	time the callback takes.
138		586
		587	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		588
		589	Calls the callback after C<$after> seconds (which may be fractional). If
		590	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		591	value as $after) after the callback returns.
		592
		593	This means that the callback would be called roughly after C<$after>
		594	seconds, and then every C<$repeat> seconds. The timer does his best not
		595	to drift, but it will not invoke the timer more often then once per event
		596	loop iteration, and might drift in other cases. If that isn't acceptable,
		597	look at EV::periodic, which can provide long-term stable timers.
		598
		599	The timer is based on a monotonic clock, that is, if somebody is sitting
		600	in front of the machine while the timer is running and changes the system
		601	clock, the timer will nevertheless run (roughly) the same time.
		602
139	The C<timer_ns> variant doesn't add/start the newly created watcher.	603	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
140		604
141	=item my $w = EV::timer_abs $at, $interval, $callback	605	=item $w->set ($after, $repeat)
142		606
143	=item my $w = EV::timer_abs_ns $at, $interval, $callback	607	Reconfigures the watcher, see the constructor above for details. Can be called at
		608	any time.
144		609
145	Similar to EV::timer, but the time is given as an absolute point in time	610	=item $w->again
146	(C<$at>), plus an optional C<$interval>.
147		611
148	If the C<$interval> is zero, then the callback will be called at the time	612	Similar to the C<start> method, but has special semantics for repeating timers:
149	C<$at> if that is in the future, or as soon as possible if its in the
150	past. It will not automatically repeat.
151		613
152	If the C<$interval> is nonzero, then the watcher will always be scheduled	614	If the timer is active and non-repeating, it will be stopped.
153	to time out at the next C<$at + integer * $interval> time.
154		615
155	This can be used to schedule a callback to run at very regular intervals,	616	If the timer is active and repeating, reset the timeout to occur
156	as long as the processing time is less then the interval (otherwise	617	C<$repeat> seconds after now.
157	obviously events will be skipped).	618
		619	If the timer is inactive and repeating, start it using the repeat value.
		620
		621	Otherwise do nothing.
		622
		623	This behaviour is useful when you have a timeout for some IO
		624	operation. You create a timer object with the same value for C<$after> and
		625	C<$repeat>, and then, in the read/write watcher, run the C<again> method
		626	on the timeout.
		627
		628	=back
		629
		630
		631	=head3 PERIODIC WATCHERS - to cron or not to cron?
		632
		633	=over 4
		634
		635	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
		636
		637	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		638
		639	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		640
		641	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
		642
		643	Similar to EV::timer, but is not based on relative timeouts but on
		644	absolute times. Apart from creating "simple" timers that trigger "at" the
		645	specified time, it can also be used for non-drifting absolute timers and
		646	more complex, cron-like, setups that are not adversely affected by time
		647	jumps (i.e. when the system clock is changed by explicit date -s or other
		648	means such as ntpd). It is also the most complex watcher type in EV.
		649
		650	It has three distinct "modes":
		651
		652	=over 4
		653
		654	=item * absolute timer ($interval = $reschedule_cb = 0)
		655
		656	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		657	will not adjust when a time jump occurs, that is, if it is to be run
		658	at January 1st 2011 then it will run when the system time reaches or
		659	surpasses this time.
		660
		661	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
		662
		663	In this mode the watcher will always be scheduled to time out at the
		664	next C<$at + N * $interval> time (for some integer N) and then repeat,
		665	regardless of any time jumps.
		666
		667	This can be used to create timers that do not drift with respect to system
		668	time:
		669
		670	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		671
		672	That doesn't mean there will always be 3600 seconds in between triggers,
		673	but only that the the clalback will be called when the system time shows a
		674	full hour (UTC).
158		675
159	Another way to think about it (for the mathematically inclined) is that	676	Another way to think about it (for the mathematically inclined) is that
160	C<timer_abs> will try to tun the callback at the next possible time where	677	EV::periodic will try to run the callback in this mode at the next
161	C<$time = $at (mod $interval)>, regardless of any time jumps.	678	possible time where C<$time = $at (mod $interval)>, regardless of any time
		679	jumps.
162		680
		681	=item * manual reschedule mode ($reschedule_cb = coderef)
		682
		683	In this mode $interval and $at are both being ignored. Instead, each
		684	time the periodic watcher gets scheduled, the reschedule callback
		685	($reschedule_cb) will be called with the watcher as first, and the current
		686	time as second argument.
		687
		688	I<This callback MUST NOT stop or destroy this or any other periodic
		689	watcher, ever, and MUST NOT call any event loop functions or methods>. If
		690	you need to stop it, return 1e30 and stop it afterwards. You may create
		691	and start a C<EV::prepare> watcher for this task.
		692
		693	It must return the next time to trigger, based on the passed time value
		694	(that is, the lowest time value larger than or equal to to the second
		695	argument). It will usually be called just before the callback will be
		696	triggered, but might be called at other times, too.
		697
		698	This can be used to create very complex timers, such as a timer that
		699	triggers on each midnight, local time (actually 24 hours after the last
		700	midnight, to keep the example simple. If you know a way to do it correctly
		701	in about the same space (without requiring elaborate modules), drop me a
		702	note :):
		703
		704	my $daily = EV::periodic 0, 0, sub {
		705	my ($w, $now) = @_;
		706
		707	use Time::Local ();
		708	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		709	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		710	}, sub {
		711	print "it's midnight or likely shortly after, now\n";
		712	};
		713
		714	=back
		715
163	The C<timer_abs_ns> variant doesn't add/start the newly created watcher.	716	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
164		717
		718	=item $w->set ($at, $interval, $reschedule_cb)
		719
		720	Reconfigures the watcher, see the constructor above for details. Can be called at
		721	any time.
		722
		723	=item $w->again
		724
		725	Simply stops and starts the watcher again.
		726
		727	=item $time = $w->at
		728
		729	Return the time that the watcher is expected to trigger next.
		730
		731	=back
		732
		733
		734	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		735
		736	=over 4
		737
165	=item my $w = EV::signal $signum, $callback	738	=item $w = EV::signal $signal, $callback
166		739
167	=item my $w = EV::signal_ns $signum, $callback	740	=item $w = EV::signal_ns $signal, $callback
168		741
169	Call the callback when signal $signum is received.	742	=item $w = $loop->signal ($signal, $callback)
170		743
		744	=item $w = $loop->signal_ns ($signal, $callback)
		745
		746	Call the callback when $signal is received (the signal can be specified by
		747	number or by name, just as with C<kill> or C<%SIG>).
		748
		749	Only one event loop can grab a given signal - attempting to grab the same
		750	signal from two EV loops will crash the program immediately or cause data
		751	corruption.
		752
		753	EV will grab the signal for the process (the kernel only allows one
		754	component to receive a signal at a time) when you start a signal watcher,
		755	and removes it again when you stop it. Perl does the same when you
		756	add/remove callbacks to C<%SIG>, so watch out.
		757
		758	You can have as many signal watchers per signal as you want.
		759
171	The C<signal_ns> variant doesn't add/start the newly created watcher.	760	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
172		761
173	=back	762	=item $w->set ($signal)
174		763
175	=head1 THE EV::Event CLASS	764	Reconfigures the watcher, see the constructor above for details. Can be
		765	called at any time.
176		766
177	All EV functions creating an event watcher (designated by C<my $w =>	767	=item $current_signum = $w->signal
178	above) support the following methods on the returned watcher object:
179		768
180	=over 4	769	=item $old_signum = $w->signal ($new_signal)
181		770
182	=item $w->add ($timeout)	771	Returns the previously set signal (always as a number not name) and
		772	optionally set a new one.
183		773
184	Stops and (re-)starts the event watcher, setting the optional timeout to	774	=back
185	the given value, or clearing the timeout if none is given.
186		775
		776
		777	=head3 CHILD WATCHERS - watch out for process status changes
		778
		779	=over 4
		780
		781	=item $w = EV::child $pid, $trace, $callback
		782
		783	=item $w = EV::child_ns $pid, $trace, $callback
		784
		785	=item $w = $loop->child ($pid, $trace, $callback)
		786
		787	=item $w = $loop->child_ns ($pid, $trace, $callback)
		788
		789	Call the callback when a status change for pid C<$pid> (or any pid
		790	if C<$pid> is 0) has been received (a status change happens when the
		791	process terminates or is killed, or, when trace is true, additionally when
		792	it is stopped or continued). More precisely: when the process receives
		793	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
		794	changed/zombie children and call the callback.
		795
		796	It is valid (and fully supported) to install a child watcher after a child
		797	has exited but before the event loop has started its next iteration (for
		798	example, first you C<fork>, then the new child process might exit, and
		799	only then do you install a child watcher in the parent for the new pid).
		800
		801	You can access both exit (or tracing) status and pid by using the
		802	C<rstatus> and C<rpid> methods on the watcher object.
		803
		804	You can have as many pid watchers per pid as you want, they will all be
		805	called.
		806
		807	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		808
		809	=item $w->set ($pid, $trace)
		810
		811	Reconfigures the watcher, see the constructor above for details. Can be called at
		812	any time.
		813
		814	=item $current_pid = $w->pid
		815
		816	Returns the previously set process id and optionally set a new one.
		817
		818	=item $exit_status = $w->rstatus
		819
		820	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		821	in perlfunc).
		822
		823	=item $pid = $w->rpid
		824
		825	Return the pid of the awaited child (useful when you have installed a
		826	watcher for all pids).
		827
		828	=back
		829
		830
		831	=head3 STAT WATCHERS - did the file attributes just change?
		832
		833	=over 4
		834
		835	=item $w = EV::stat $path, $interval, $callback
		836
		837	=item $w = EV::stat_ns $path, $interval, $callback
		838
		839	=item $w = $loop->stat ($path, $interval, $callback)
		840
		841	=item $w = $loop->stat_ns ($path, $interval, $callback)
		842
		843	Call the callback when a file status change has been detected on
		844	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		845	to "path does not exist" is a status change like any other.
		846
		847	The C<$interval> is a recommended polling interval for systems where
		848	OS-supported change notifications don't exist or are not supported. If
		849	you use C<0> then an unspecified default is used (which is highly
		850	recommended!), which is to be expected to be around five seconds usually.
		851
		852	This watcher type is not meant for massive numbers of stat watchers,
		853	as even with OS-supported change notifications, this can be
		854	resource-intensive.
		855
		856	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		857
187	=item $w->start	858	=item ... = $w->stat
188		859
189	Stops and (re-)starts the event watcher without touching the timeout.	860	This call is very similar to the perl C<stat> built-in: It stats (using
		861	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		862	well as EV's idea of the current stat values) to the values found.
190		863
191	=item $w->del	864	In scalar context, a boolean is return indicating success or failure of
		865	the stat. In list context, the same 13-value list as with stat is returned
		866	(except that the blksize and blocks fields are not reliable).
192		867
193	=item $w->stop	868	In the case of an error, errno is set to C<ENOENT> (regardless of the
		869	actual error value) and the C<nlink> value is forced to zero (if the stat
		870	was successful then nlink is guaranteed to be non-zero).
194		871
195	Stop the event watcher if it was started.	872	See also the next two entries for more info.
196		873
197	=item $current_callback = $w->cb	874	=item ... = $w->attr
198		875
199	=item $old_callback = $w->cb ($new_callback)	876	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		877	the values most recently detected by EV. See the next entry for more info.
200		878
		879	=item ... = $w->prev
		880
		881	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		882	the previous set of values, before the change.
		883
		884	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		885	to the values found I<before> a change was detected, while C<< $w->attr >>
		886	returns the values found leading to the change detection. The difference (if any)
		887	between C<prev> and C<attr> is what triggered the callback.
		888
		889	If you did something to the filesystem object and do not want to trigger
		890	yet another change, you can call C<stat> to update EV's idea of what the
		891	current attributes are.
		892
		893	=item $w->set ($path, $interval)
		894
		895	Reconfigures the watcher, see the constructor above for details. Can be
		896	called at any time.
		897
		898	=item $current_path = $w->path
		899
		900	=item $old_path = $w->path ($new_path)
		901
201	Return the previously set callback and optionally set a new one.	902	Returns the previously set path and optionally set a new one.
202		903
203	=item $current_fh = $w->fh	904	=item $current_interval = $w->interval
204		905
205	=item $old_fh = $w->fh ($new_fh)	906	=item $old_interval = $w->interval ($new_interval)
206		907
207	Returns the previously set filehandle and optionally set a new one.
208
209	=item $current_eventmask = $w->events
210
211	=item $old_eventmask = $w->events ($new_eventmask)
212
213	Returns the previously set event mask and optionally set a new one.	908	Returns the previously set interval and optionally set a new one. Can be
		909	used to query the actual interval used.
214		910
215	=item $w->timeout ($after, $repeat)
216
217	Resets the timeout (see C<EV::timer> for details).
218
219	=item $w->timeout_abs ($at, $interval)
220
221	Resets the timeout (see C<EV::timer_abs> for details).
222
223	=item $w->priority_set ($priority)
224
225	Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI).
226
227	=back	911	=back
228		912
229	=head1 BUGS
230		913
231	Lots. Libevent itself isn't well tested and rather buggy, and this module	914	=head3 IDLE WATCHERS - when you've got nothing better to do...
232	is quite new at the moment.
233		915
234	Please note that the epoll method is not, in general, reliable in programs	916	=over 4
235	that use fork (even if no libveent calls are being made in the forked
236	process). If your program behaves erratically, try setting the environment
237	variable C<EVENT_NOEPOLL> first when running the program.
238		917
239	In general, if you fork, then you can only use the EV module in one of the	918	=item $w = EV::idle $callback
240	children.	919
		920	=item $w = EV::idle_ns $callback
		921
		922	=item $w = $loop->idle ($callback)
		923
		924	=item $w = $loop->idle_ns ($callback)
		925
		926	Call the callback when there are no other pending watchers of the same or
		927	higher priority (excluding check, prepare and other idle watchers of the
		928	same or lower priority, of course). They are called idle watchers because
		929	when the watcher is the highest priority pending event in the process, the
		930	process is considered to be idle at that priority.
		931
		932	If you want a watcher that is only ever called when I<no> other events are
		933	outstanding you have to set the priority to C<EV::MINPRI>.
		934
		935	The process will not block as long as any idle watchers are active, and
		936	they will be called repeatedly until stopped.
		937
		938	For example, if you have idle watchers at priority C<0> and C<1>, and
		939	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		940	and the I/O watcher will always run when ready. Only when the idle watcher
		941	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		942	pending with the C<0>-priority idle watcher be invoked.
		943
		944	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
		945
		946	=back
		947
		948
		949	=head3 PREPARE WATCHERS - customise your event loop!
		950
		951	=over 4
		952
		953	=item $w = EV::prepare $callback
		954
		955	=item $w = EV::prepare_ns $callback
		956
		957	=item $w = $loop->prepare ($callback)
		958
		959	=item $w = $loop->prepare_ns ($callback)
		960
		961	Call the callback just before the process would block. You can still
		962	create/modify any watchers at this point.
		963
		964	See the EV::check watcher, below, for explanations and an example.
		965
		966	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
		967
		968	=back
		969
		970
		971	=head3 CHECK WATCHERS - customise your event loop even more!
		972
		973	=over 4
		974
		975	=item $w = EV::check $callback
		976
		977	=item $w = EV::check_ns $callback
		978
		979	=item $w = $loop->check ($callback)
		980
		981	=item $w = $loop->check_ns ($callback)
		982
		983	Call the callback just after the process wakes up again (after it has
		984	gathered events), but before any other callbacks have been invoked.
		985
		986	This can be used to integrate other event-based software into the EV
		987	mainloop: You register a prepare callback and in there, you create io and
		988	timer watchers as required by the other software. Here is a real-world
		989	example of integrating Net::SNMP (with some details left out):
		990
		991	our @snmp_watcher;
		992
		993	our $snmp_prepare = EV::prepare sub {
		994	# do nothing unless active
		995	$dispatcher->{_event_queue_h}
		996	or return;
		997
		998	# make the dispatcher handle any outstanding stuff
		999	... not shown
		1000
		1001	# create an I/O watcher for each and every socket
		1002	@snmp_watcher = (
		1003	(map { EV::io $_, EV::READ, sub { } }
		1004	keys %{ $dispatcher->{_descriptors} }),
		1005
		1006	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		1007	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		1008	0, sub { },
		1009	);
		1010	};
		1011
		1012	The callbacks are irrelevant (and are not even being called), the
		1013	only purpose of those watchers is to wake up the process as soon as
		1014	one of those events occurs (socket readable, or timer timed out). The
		1015	corresponding EV::check watcher will then clean up:
		1016
		1017	our $snmp_check = EV::check sub {
		1018	# destroy all watchers
		1019	@snmp_watcher = ();
		1020
		1021	# make the dispatcher handle any new stuff
		1022	... not shown
		1023	};
		1024
		1025	The callbacks of the created watchers will not be called as the watchers
		1026	are destroyed before this can happen (remember EV::check gets called
		1027	first).
		1028
		1029	The C<check_ns> variant doesn't start (activate) the newly created watcher.
		1030
		1031	=item EV::CHECK constant issues
		1032
		1033	Like all other watcher types, there is a bitmask constant for use in
		1034	C<$revents> and other places. The C<EV::CHECK> is special as it has
		1035	the same name as the C<CHECK> sub called by Perl. This doesn't cause
		1036	big issues on newer perls (beginning with 5.8.9), but it means thatthe
		1037	constant must be I<inlined>, i.e. runtime calls will not work. That means
		1038	that as long as you always C<use EV> and then C<EV::CHECK> you are on the
		1039	safe side.
		1040
		1041	=back
		1042
		1043
		1044	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		1045
		1046	Fork watchers are called when a C<fork ()> was detected. The invocation
		1047	is done before the event loop blocks next and before C<check> watchers
		1048	are being called, and only in the child after the fork.
		1049
		1050	=over 4
		1051
		1052	=item $w = EV::fork $callback
		1053
		1054	=item $w = EV::fork_ns $callback
		1055
		1056	=item $w = $loop->fork ($callback)
		1057
		1058	=item $w = $loop->fork_ns ($callback)
		1059
		1060	Call the callback before the event loop is resumed in the child process
		1061	after a fork.
		1062
		1063	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		1064
		1065	=back
		1066
		1067
		1068	=head3 EMBED WATCHERS - when one backend isn't enough...
		1069
		1070	This is a rather advanced watcher type that lets you embed one event loop
		1071	into another (currently only IO events are supported in the embedded
		1072	loop, other types of watchers might be handled in a delayed or incorrect
		1073	fashion and must not be used).
		1074
		1075	See the libev documentation at
		1076	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1077	(locally installed as F<EV::libev>) for more details.
		1078
		1079	In short, this watcher is most useful on BSD systems without working
		1080	kqueue to still be able to handle a large number of sockets:
		1081
		1082	my $socket_loop;
		1083
		1084	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1085	if (
		1086	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1087	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1088	) {
		1089	# use kqueue for sockets
		1090	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1091	}
		1092
		1093	# use the default loop otherwise
		1094	$socket_loop \|\|= EV::default_loop;
		1095
		1096	=over 4
		1097
		1098	=item $w = EV::embed $otherloop[, $callback]
		1099
		1100	=item $w = EV::embed_ns $otherloop[, $callback]
		1101
		1102	=item $w = $loop->embed ($otherloop[, $callback])
		1103
		1104	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1105
		1106	Call the callback when the embedded event loop (C<$otherloop>) has any
		1107	I/O activity. The C<$callback> is optional: if it is missing, then the
		1108	embedded event loop will be managed automatically (which is recommended),
		1109	otherwise you have to invoke C<sweep> yourself.
		1110
		1111	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1112
		1113	=back
		1114
		1115	=head3 ASYNC WATCHERS - how to wake up another event loop
		1116
		1117	Async watchers are provided by EV, but have little use in perl directly,
		1118	as perl neither supports threads running in parallel nor direct access to
		1119	signal handlers or other contexts where they could be of value.
		1120
		1121	It is, however, possible to use them from the XS level.
		1122
		1123	Please see the libev documentation for further details.
		1124
		1125	=over 4
		1126
		1127	=item $w = EV::async $callback
		1128
		1129	=item $w = EV::async_ns $callback
		1130
		1131	=item $w->send
		1132
		1133	=item $bool = $w->async_pending
		1134
		1135	=back
		1136
		1137
		1138	=head1 PERL SIGNALS
		1139
		1140	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1141	with EV is as the same as any other C library: Perl-signals will only be
		1142	handled when Perl runs, which means your signal handler might be invoked
		1143	only the next time an event callback is invoked.
		1144
		1145	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1146	ensure proper operations with regards to other event watchers.
		1147
		1148	If you cannot do this for whatever reason, you can also force a watcher
		1149	to be called on every event loop iteration by installing a C<EV::check>
		1150	watcher:
		1151
		1152	my $async_check = EV::check sub { };
		1153
		1154	This ensures that perl gets into control for a short time to handle any
		1155	pending signals, and also ensures (slightly) slower overall operation.
		1156
		1157	=head1 ITHREADS
		1158
		1159	Ithreads are not supported by this module in any way. Perl pseudo-threads
		1160	is evil stuff and must die. Real threads as provided by Coro are fully
		1161	supported (and enhanced support is available via L<Coro::EV>).
		1162
		1163	=head1 FORK
		1164
		1165	Most of the "improved" event delivering mechanisms of modern operating
		1166	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1167	not supported and usually destructive). Libev makes it possible to work
		1168	around this by having a function that recreates the kernel state after
		1169	fork in the child.
		1170
		1171	On non-win32 platforms, this module requires the pthread_atfork
		1172	functionality to do this automatically for you. This function is quite
		1173	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1174	negligible, because everything the function currently does is set a flag
		1175	that is checked only when the event loop gets used the next time, so when
		1176	you do fork but not use EV, the overhead is minimal.
		1177
		1178	On win32, there is no notion of fork so all this doesn't apply, of course.
241		1179
242	=cut	1180	=cut
243		1181
244	our $DIED = sub {	1182	our $DIED = sub {
245	warn "EV: error in callback (ignoring): $@";	1183	warn "EV: error in callback (ignoring): $@";
246	};	1184	};
247		1185
248	our $NPRI = 4;	1186	default_loop
249	our $BASE = init;	1187	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
250	priority_init $NPRI;
251
252	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
253		1188
254	1;	1189	1;
255		1190
256	=head1 SEE ALSO	1191	=head1 SEE ALSO
257		1192
258	L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>.	1193	L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
259	L<EV::AnyEvent>.	1194	(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
		1195	loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
		1196	integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1197	event-loop agnostic and portable event driven programming.
260		1198
261	=head1 AUTHOR	1199	=head1 AUTHOR
262		1200
263	Marc Lehmann <schmorp@schmorp.de>	1201	Marc Lehmann <schmorp@schmorp.de>
264	http://home.schmorp.de/	1202	http://home.schmorp.de/
265		1203
266	=cut	1204	=cut
267		1205

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Comparing EV/EV.pm (file contents): Revision 1.8 by root, Sat Oct 27 19:11:27 2007 UTC vs. Revision 1.130 by root, Sun Oct 24 17:58:41 2010 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.8 by root, Sat Oct 27 19:11:27 2007 UTC vs.
Revision 1.130 by root, Sun Oct 24 17:58:41 2010 UTC