[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 1.123 by root, Sun Aug 9 13:30:41 2009 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 = '3.8';
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::TIMEOUT>).
		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), and EV::timer (which
		372	uses EV::TIMEOUT).
		373
		374	In the rare case where one wants to create a watcher but not start it at
		375	the same time, each constructor has a variant with a trailing C<_ns> in
		376	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
		377
		378	Please note that a watcher will automatically be stopped when the watcher
		379	object is destroyed, so you I<need> to keep the watcher objects returned by
		380	the constructors.
		381
		382	Also, all methods changing some aspect of a watcher (->set, ->priority,
		383	->fh and so on) automatically stop and start it again if it is active,
		384	which means pending events get lost.
		385
		386	=head2 COMMON WATCHER METHODS
		387
		388	This section lists methods common to all watchers.
		389
		390	=over 4
		391
		392	=item $w->start
		393
		394	Starts a watcher if it isn't active already. Does nothing to an already
		395	active watcher. By default, all watchers start out in the active state
		396	(see the description of the C<_ns> variants if you need stopped watchers).
		397
		398	=item $w->stop
		399
		400	Stop a watcher if it is active. Also clear any pending events (events that
		401	have been received but that didn't yet result in a callback invocation),
		402	regardless of whether the watcher was active or not.
		403
		404	=item $bool = $w->is_active
		405
		406	Returns true if the watcher is active, false otherwise.
		407
		408	=item $current_data = $w->data
		409
		410	=item $old_data = $w->data ($new_data)
		411
		412	Queries a freely usable data scalar on the watcher and optionally changes
		413	it. This is a way to associate custom data with a watcher:
		414
		415	my $w = EV::timer 60, 0, sub {
		416	warn $_[0]->data;
		417	};
		418	$w->data ("print me!");
		419
		420	=item $current_cb = $w->cb
		421
		422	=item $old_cb = $w->cb ($new_cb)
		423
		424	Queries the callback on the watcher and optionally changes it. You can do
		425	this at any time without the watcher restarting.
		426
		427	=item $current_priority = $w->priority
		428
		429	=item $old_priority = $w->priority ($new_priority)
		430
		431	Queries the priority on the watcher and optionally changes it. Pending
		432	watchers with higher priority will be invoked first. The valid range of
		433	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		434	-2). If the priority is outside this range it will automatically be
		435	normalised to the nearest valid priority.
		436
		437	The default priority of any newly-created watcher is 0.
		438
		439	Note that the priority semantics have not yet been fleshed out and are
		440	subject to almost certain change.
		441
		442	=item $w->invoke ($revents)
		443
		444	Call the callback now with the given event mask.
		445
		446	=item $w->feed_event ($revents)
		447
		448	Feed some events on this watcher into EV. EV will react to this call as if
		449	the watcher had received the given C<$revents> mask.
		450
		451	=item $revents = $w->clear_pending
		452
		453	If the watcher is pending, this function clears its pending status and
		454	returns its C<$revents> bitset (as if its callback was invoked). If the
		455	watcher isn't pending it does nothing and returns C<0>.
		456
		457	=item $previous_state = $w->keepalive ($bool)
		458
		459	Normally, C<EV::loop> will return when there are no active watchers
		460	(which is a "deadlock" because no progress can be made anymore). This is
		461	convinient because it allows you to start your watchers (and your jobs),
		462	call C<EV::loop> once and when it returns you know that all your jobs are
		463	finished (or they forgot to register some watchers for their task :).
		464
		465	Sometimes, however, this gets in your way, for example when the module
		466	that calls C<EV::loop> (usually the main program) is not the same module
		467	as a long-living watcher (for example a DNS client module written by
		468	somebody else even). Then you might want any outstanding requests to be
		469	handled, but you would not want to keep C<EV::loop> from returning just
		470	because you happen to have this long-running UDP port watcher.
		471
		472	In this case you can clear the keepalive status, which means that even
		473	though your watcher is active, it won't keep C<EV::loop> from returning.
		474
		475	The initial value for keepalive is true (enabled), and you can change it
		476	any time.
		477
		478	Example: Register an I/O watcher for some UDP socket but do not keep the
		479	event loop from running just because of that watcher.
		480
		481	my $udp_socket = ...
		482	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		483	$udp_watcher->keepalive (0);
		484
		485	=item $loop = $w->loop
		486
		487	Return the loop that this watcher is attached to.
		488
		489	=back
		490
		491
		492	=head1 WATCHER TYPES
		493
		494	Each of the following subsections describes a single watcher type.
		495
		496	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		497
		498	=over 4
		499
127	=item my $w = EV::io $fileno_or_fh, $eventmask, $callback	500	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
128		501
129	=item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	502	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		503
		504	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		505
		506	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
130		507
131	As long as the returned watcher object is alive, call the C<$callback>	508	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	509	when at least one of events specified in C<$eventmask> occurs.
133	is disabled.
134		510
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:	511	The $eventmask can be one or more of these constants ORed together:
144		512
145	EV::READ wait until read() wouldn't block anymore	513	EV::READ wait until read() wouldn't block anymore
146	EV::WRITE wait until write() wouldn't block anymore	514	EV::WRITE wait until write() wouldn't block anymore
147	EV::PERSIST stay active after a (non-timeout) event occured
148		515
149	The C<io_ns> variant doesn't add/start the newly created watcher.	516	The C<io_ns> variant doesn't start (activate) the newly created watcher.
150		517
151	=item my $w = EV::timed_io $fileno_or_fh, $eventmask, $timeout, $callback	518	=item $w->set ($fileno_or_fh, $eventmask)
152		519
153	=item my $w = EV::timed_io_ns $fileno_or_fh, $eventmask, $timeout, $callback	520	Reconfigures the watcher, see the constructor above for details. Can be
		521	called at any time.
154		522
155	Same as C<io> and C<io_ns>, but also specifies a timeout (as if there was	523	=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		524
159	If the timeout is zero or undef, no timeout will be set, and a normal	525	=item $old_fh = $w->fh ($new_fh)
160	watcher (with the persist flag set!) will be created.
161		526
162	This has the effect of timing out after the specified period of inactivity	527	Returns the previously set filehandle and optionally set a new one.
163	has happened.
164		528
165	Due to the design of libevent, this is also relatively inefficient, having	529	=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		530
		531	=item $old_eventmask = $w->events ($new_eventmask)
		532
		533	Returns the previously set event mask and optionally set a new one.
		534
		535	=back
		536
		537
		538	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		539
		540	=over 4
		541
169	=item my $w = EV::timer $after, $repeat, $callback	542	=item $w = EV::timer $after, $repeat, $callback
170		543
171	=item my $w = EV::timer_ns $after, $repeat, $callback	544	=item $w = EV::timer_ns $after, $repeat, $callback
172		545
173	Calls the callback after C<$after> seconds. If C<$repeat> is true, the	546	=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		547
		548	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		549
		550	Calls the callback after C<$after> seconds (which may be fractional). If
		551	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		552	value as $after) after the callback returns.
		553
		554	This means that the callback would be called roughly after C<$after>
		555	seconds, and then every C<$repeat> seconds. The timer does his best not
		556	to drift, but it will not invoke the timer more often then once per event
		557	loop iteration, and might drift in other cases. If that isn't acceptable,
		558	look at EV::periodic, which can provide long-term stable timers.
		559
		560	The timer is based on a monotonic clock, that is, if somebody is sitting
		561	in front of the machine while the timer is running and changes the system
		562	clock, the timer will nevertheless run (roughly) the same time.
		563
178	The C<timer_ns> variant doesn't add/start the newly created watcher.	564	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
179		565
180	=item my $w = EV::timer_abs $at, $interval, $callback	566	=item $w->set ($after, $repeat)
181		567
182	=item my $w = EV::timer_abs_ns $at, $interval, $callback	568	Reconfigures the watcher, see the constructor above for details. Can be called at
		569	any time.
183		570
184	Similar to EV::timer, but the time is given as an absolute point in time	571	=item $w->again
185	(C<$at>), plus an optional C<$interval>.
186		572
187	If the C<$interval> is zero, then the callback will be called at the time	573	Similar to the C<start> method, but has special semantics for repeating timers:
188	C<$at> if that is in the future, or as soon as possible if its in the
189	past. It will not automatically repeat.
190		574
191	If the C<$interval> is nonzero, then the watcher will always be scheduled	575	If the timer is active and non-repeating, it will be stopped.
192	to time out at the next C<$at + integer * $interval> time.
193		576
194	This can be used to schedule a callback to run at very regular intervals,	577	If the timer is active and repeating, reset the timeout to occur
195	as long as the processing time is less then the interval (otherwise	578	C<$repeat> seconds after now.
196	obviously events will be skipped).	579
		580	If the timer is inactive and repeating, start it using the repeat value.
		581
		582	Otherwise do nothing.
		583
		584	This behaviour is useful when you have a timeout for some IO
		585	operation. You create a timer object with the same value for C<$after> and
		586	C<$repeat>, and then, in the read/write watcher, run the C<again> method
		587	on the timeout.
		588
		589	=back
		590
		591
		592	=head3 PERIODIC WATCHERS - to cron or not to cron?
		593
		594	=over 4
		595
		596	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
		597
		598	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		599
		600	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		601
		602	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
		603
		604	Similar to EV::timer, but is not based on relative timeouts but on
		605	absolute times. Apart from creating "simple" timers that trigger "at" the
		606	specified time, it can also be used for non-drifting absolute timers and
		607	more complex, cron-like, setups that are not adversely affected by time
		608	jumps (i.e. when the system clock is changed by explicit date -s or other
		609	means such as ntpd). It is also the most complex watcher type in EV.
		610
		611	It has three distinct "modes":
		612
		613	=over 4
		614
		615	=item * absolute timer ($interval = $reschedule_cb = 0)
		616
		617	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		618	will not adjust when a time jump occurs, that is, if it is to be run
		619	at January 1st 2011 then it will run when the system time reaches or
		620	surpasses this time.
		621
		622	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
		623
		624	In this mode the watcher will always be scheduled to time out at the
		625	next C<$at + N * $interval> time (for some integer N) and then repeat,
		626	regardless of any time jumps.
		627
		628	This can be used to create timers that do not drift with respect to system
		629	time:
		630
		631	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		632
		633	That doesn't mean there will always be 3600 seconds in between triggers,
		634	but only that the the clalback will be called when the system time shows a
		635	full hour (UTC).
197		636
198	Another way to think about it (for the mathematically inclined) is that	637	Another way to think about it (for the mathematically inclined) is that
199	C<timer_abs> will try to tun the callback at the next possible time where	638	EV::periodic will try to run the callback in this mode at the next
200	C<$time = $at (mod $interval)>, regardless of any time jumps.	639	possible time where C<$time = $at (mod $interval)>, regardless of any time
		640	jumps.
201		641
		642	=item * manual reschedule mode ($reschedule_cb = coderef)
		643
		644	In this mode $interval and $at are both being ignored. Instead, each
		645	time the periodic watcher gets scheduled, the reschedule callback
		646	($reschedule_cb) will be called with the watcher as first, and the current
		647	time as second argument.
		648
		649	I<This callback MUST NOT stop or destroy this or any other periodic
		650	watcher, ever, and MUST NOT call any event loop functions or methods>. If
		651	you need to stop it, return 1e30 and stop it afterwards. You may create
		652	and start a C<EV::prepare> watcher for this task.
		653
		654	It must return the next time to trigger, based on the passed time value
		655	(that is, the lowest time value larger than or equal to to the second
		656	argument). It will usually be called just before the callback will be
		657	triggered, but might be called at other times, too.
		658
		659	This can be used to create very complex timers, such as a timer that
		660	triggers on each midnight, local time (actually 24 hours after the last
		661	midnight, to keep the example simple. If you know a way to do it correctly
		662	in about the same space (without requiring elaborate modules), drop me a
		663	note :):
		664
		665	my $daily = EV::periodic 0, 0, sub {
		666	my ($w, $now) = @_;
		667
		668	use Time::Local ();
		669	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		670	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		671	}, sub {
		672	print "it's midnight or likely shortly after, now\n";
		673	};
		674
		675	=back
		676
202	The C<timer_abs_ns> variant doesn't add/start the newly created watcher.	677	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
203		678
		679	=item $w->set ($at, $interval, $reschedule_cb)
		680
		681	Reconfigures the watcher, see the constructor above for details. Can be called at
		682	any time.
		683
		684	=item $w->again
		685
		686	Simply stops and starts the watcher again.
		687
		688	=item $time = $w->at
		689
		690	Return the time that the watcher is expected to trigger next.
		691
		692	=back
		693
		694
		695	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		696
		697	=over 4
		698
204	=item my $w = EV::signal $signal, $callback	699	=item $w = EV::signal $signal, $callback
205		700
206	=item my $w = EV::signal_ns $signal, $callback	701	=item $w = EV::signal_ns $signal, $callback
207		702
		703	=item $w = $loop->signal ($signal, $callback)
		704
		705	=item $w = $loop->signal_ns ($signal, $callback)
		706
208	Call the callback when $signal is received (the signal can be specified	707	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	708	number or by name, just as with C<kill> or C<%SIG>).
210	persistent no natter what.	709
		710	Only one event loop can grab a given signal - attempting to grab the same
		711	signal from two EV loops will crash the program immediately or cause data
		712	corruption.
211		713
212	EV will grab the signal for the process (the kernel only allows one	714	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	715	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	716	and removes it again when you stop it. Perl does the same when you
215	callbacks to %SIG, so watch out.	717	add/remove callbacks to C<%SIG>, so watch out.
216		718
217	Unfortunately, only one handler can be registered per signal. Screw	719	You can have as many signal watchers per signal as you want.
218	libevent.
219		720
220	The C<signal_ns> variant doesn't add/start the newly created watcher.	721	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
221		722
222	=back	723	=item $w->set ($signal)
223		724
224	=head1 THE EV::Event CLASS	725	Reconfigures the watcher, see the constructor above for details. Can be
		726	called at any time.
225		727
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	728	=item $current_signum = $w->signal
260		729
261	=item $old_signal = $w->signal ($new_signal)	730	=item $old_signum = $w->signal ($new_signal)
262		731
		732	Returns the previously set signal (always as a number not name) and
		733	optionally set a new one.
		734
		735	=back
		736
		737
		738	=head3 CHILD WATCHERS - watch out for process status changes
		739
		740	=over 4
		741
		742	=item $w = EV::child $pid, $trace, $callback
		743
		744	=item $w = EV::child_ns $pid, $trace, $callback
		745
		746	=item $w = $loop->child ($pid, $trace, $callback)
		747
		748	=item $w = $loop->child_ns ($pid, $trace, $callback)
		749
		750	Call the callback when a status change for pid C<$pid> (or any pid
		751	if C<$pid> is 0) has been received (a status change happens when the
		752	process terminates or is killed, or, when trace is true, additionally when
		753	it is stopped or continued). More precisely: when the process receives
		754	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
		755	changed/zombie children and call the callback.
		756
		757	It is valid (and fully supported) to install a child watcher after a child
		758	has exited but before the event loop has started its next iteration (for
		759	example, first you C<fork>, then the new child process might exit, and
		760	only then do you install a child watcher in the parent for the new pid).
		761
		762	You can access both exit (or tracing) status and pid by using the
		763	C<rstatus> and C<rpid> methods on the watcher object.
		764
		765	You can have as many pid watchers per pid as you want, they will all be
		766	called.
		767
		768	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		769
		770	=item $w->set ($pid, $trace)
		771
		772	Reconfigures the watcher, see the constructor above for details. Can be called at
		773	any time.
		774
		775	=item $current_pid = $w->pid
		776
263	Returns the previously set signal number and optionally set a new one (also sets	777	Returns the previously set process id and optionally set a new one.
264	the EV::SIGNAL flag when setting a signal).
265		778
266	=item $current_eventmask = $w->events	779	=item $exit_status = $w->rstatus
267		780
268	=item $old_eventmask = $w->events ($new_eventmask)	781	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		782	in perlfunc).
269		783
		784	=item $pid = $w->rpid
		785
		786	Return the pid of the awaited child (useful when you have installed a
		787	watcher for all pids).
		788
		789	=back
		790
		791
		792	=head3 STAT WATCHERS - did the file attributes just change?
		793
		794	=over 4
		795
		796	=item $w = EV::stat $path, $interval, $callback
		797
		798	=item $w = EV::stat_ns $path, $interval, $callback
		799
		800	=item $w = $loop->stat ($path, $interval, $callback)
		801
		802	=item $w = $loop->stat_ns ($path, $interval, $callback)
		803
		804	Call the callback when a file status change has been detected on
		805	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		806	to "path does not exist" is a status change like any other.
		807
		808	The C<$interval> is a recommended polling interval for systems where
		809	OS-supported change notifications don't exist or are not supported. If
		810	you use C<0> then an unspecified default is used (which is highly
		811	recommended!), which is to be expected to be around five seconds usually.
		812
		813	This watcher type is not meant for massive numbers of stat watchers,
		814	as even with OS-supported change notifications, this can be
		815	resource-intensive.
		816
		817	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		818
		819	=item ... = $w->stat
		820
		821	This call is very similar to the perl C<stat> built-in: It stats (using
		822	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		823	well as EV's idea of the current stat values) to the values found.
		824
		825	In scalar context, a boolean is return indicating success or failure of
		826	the stat. In list context, the same 13-value list as with stat is returned
		827	(except that the blksize and blocks fields are not reliable).
		828
		829	In the case of an error, errno is set to C<ENOENT> (regardless of the
		830	actual error value) and the C<nlink> value is forced to zero (if the stat
		831	was successful then nlink is guaranteed to be non-zero).
		832
		833	See also the next two entries for more info.
		834
		835	=item ... = $w->attr
		836
		837	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		838	the values most recently detected by EV. See the next entry for more info.
		839
		840	=item ... = $w->prev
		841
		842	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		843	the previous set of values, before the change.
		844
		845	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		846	to the values found I<before> a change was detected, while C<< $w->attr >>
		847	returns the values found leading to the change detection. The difference (if any)
		848	between C<prev> and C<attr> is what triggered the callback.
		849
		850	If you did something to the filesystem object and do not want to trigger
		851	yet another change, you can call C<stat> to update EV's idea of what the
		852	current attributes are.
		853
		854	=item $w->set ($path, $interval)
		855
		856	Reconfigures the watcher, see the constructor above for details. Can be
		857	called at any time.
		858
		859	=item $current_path = $w->path
		860
		861	=item $old_path = $w->path ($new_path)
		862
270	Returns the previously set event mask and optionally set a new one.	863	Returns the previously set path and optionally set a new one.
271		864
272	=item $w->timeout ($after, $repeat)	865	=item $current_interval = $w->interval
273		866
274	Resets the timeout (see C<EV::timer> for details).	867	=item $old_interval = $w->interval ($new_interval)
275		868
276	=item $w->timeout_abs ($at, $interval)	869	Returns the previously set interval and optionally set a new one. Can be
		870	used to query the actual interval used.
277		871
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	872	=back
285		873
286	=head1 BUGS
287		874
288	Lots. Libevent itself isn't well tested and rather buggy, and this module	875	=head3 IDLE WATCHERS - when you've got nothing better to do...
289	is quite new at the moment.
290		876
291	Please note that the epoll method is not, in general, reliable in programs	877	=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		878
296	In general, if you fork, then you can only use the EV module in one of the	879	=item $w = EV::idle $callback
297	children.	880
		881	=item $w = EV::idle_ns $callback
		882
		883	=item $w = $loop->idle ($callback)
		884
		885	=item $w = $loop->idle_ns ($callback)
		886
		887	Call the callback when there are no other pending watchers of the same or
		888	higher priority (excluding check, prepare and other idle watchers of the
		889	same or lower priority, of course). They are called idle watchers because
		890	when the watcher is the highest priority pending event in the process, the
		891	process is considered to be idle at that priority.
		892
		893	If you want a watcher that is only ever called when I<no> other events are
		894	outstanding you have to set the priority to C<EV::MINPRI>.
		895
		896	The process will not block as long as any idle watchers are active, and
		897	they will be called repeatedly until stopped.
		898
		899	For example, if you have idle watchers at priority C<0> and C<1>, and
		900	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		901	and the I/O watcher will always run when ready. Only when the idle watcher
		902	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		903	pending with the C<0>-priority idle watcher be invoked.
		904
		905	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
		906
		907	=back
		908
		909
		910	=head3 PREPARE WATCHERS - customise your event loop!
		911
		912	=over 4
		913
		914	=item $w = EV::prepare $callback
		915
		916	=item $w = EV::prepare_ns $callback
		917
		918	=item $w = $loop->prepare ($callback)
		919
		920	=item $w = $loop->prepare_ns ($callback)
		921
		922	Call the callback just before the process would block. You can still
		923	create/modify any watchers at this point.
		924
		925	See the EV::check watcher, below, for explanations and an example.
		926
		927	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
		928
		929	=back
		930
		931
		932	=head3 CHECK WATCHERS - customise your event loop even more!
		933
		934	=over 4
		935
		936	=item $w = EV::check $callback
		937
		938	=item $w = EV::check_ns $callback
		939
		940	=item $w = $loop->check ($callback)
		941
		942	=item $w = $loop->check_ns ($callback)
		943
		944	Call the callback just after the process wakes up again (after it has
		945	gathered events), but before any other callbacks have been invoked.
		946
		947	This is used to integrate other event-based software into the EV
		948	mainloop: You register a prepare callback and in there, you create io and
		949	timer watchers as required by the other software. Here is a real-world
		950	example of integrating Net::SNMP (with some details left out):
		951
		952	our @snmp_watcher;
		953
		954	our $snmp_prepare = EV::prepare sub {
		955	# do nothing unless active
		956	$dispatcher->{_event_queue_h}
		957	or return;
		958
		959	# make the dispatcher handle any outstanding stuff
		960	... not shown
		961
		962	# create an I/O watcher for each and every socket
		963	@snmp_watcher = (
		964	(map { EV::io $_, EV::READ, sub { } }
		965	keys %{ $dispatcher->{_descriptors} }),
		966
		967	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		968	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		969	0, sub { },
		970	);
		971	};
		972
		973	The callbacks are irrelevant (and are not even being called), the
		974	only purpose of those watchers is to wake up the process as soon as
		975	one of those events occurs (socket readable, or timer timed out). The
		976	corresponding EV::check watcher will then clean up:
		977
		978	our $snmp_check = EV::check sub {
		979	# destroy all watchers
		980	@snmp_watcher = ();
		981
		982	# make the dispatcher handle any new stuff
		983	... not shown
		984	};
		985
		986	The callbacks of the created watchers will not be called as the watchers
		987	are destroyed before this can happen (remember EV::check gets called
		988	first).
		989
		990	The C<check_ns> variant doesn't start (activate) the newly created watcher.
		991
		992	=back
		993
		994
		995	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		996
		997	Fork watchers are called when a C<fork ()> was detected. The invocation
		998	is done before the event loop blocks next and before C<check> watchers
		999	are being called, and only in the child after the fork.
		1000
		1001	=over 4
		1002
		1003	=item $w = EV::fork $callback
		1004
		1005	=item $w = EV::fork_ns $callback
		1006
		1007	=item $w = $loop->fork ($callback)
		1008
		1009	=item $w = $loop->fork_ns ($callback)
		1010
		1011	Call the callback before the event loop is resumed in the child process
		1012	after a fork.
		1013
		1014	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		1015
		1016	=back
		1017
		1018
		1019	=head3 EMBED WATCHERS - when one backend isn't enough...
		1020
		1021	This is a rather advanced watcher type that lets you embed one event loop
		1022	into another (currently only IO events are supported in the embedded
		1023	loop, other types of watchers might be handled in a delayed or incorrect
		1024	fashion and must not be used).
		1025
		1026	See the libev documentation at
		1027	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1028	(locally installed as F<EV::libev>) for more details.
		1029
		1030	In short, this watcher is most useful on BSD systems without working
		1031	kqueue to still be able to handle a large number of sockets:
		1032
		1033	my $socket_loop;
		1034
		1035	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1036	if (
		1037	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1038	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1039	) {
		1040	# use kqueue for sockets
		1041	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1042	}
		1043
		1044	# use the default loop otherwise
		1045	$socket_loop \|\|= EV::default_loop;
		1046
		1047	=over 4
		1048
		1049	=item $w = EV::embed $otherloop[, $callback]
		1050
		1051	=item $w = EV::embed_ns $otherloop[, $callback]
		1052
		1053	=item $w = $loop->embed ($otherloop[, $callback])
		1054
		1055	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1056
		1057	Call the callback when the embedded event loop (C<$otherloop>) has any
		1058	I/O activity. The C<$callback> is optional: if it is missing, then the
		1059	embedded event loop will be managed automatically (which is recommended),
		1060	otherwise you have to invoke C<sweep> yourself.
		1061
		1062	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1063
		1064	=back
		1065
		1066	=head3 ASYNC WATCHERS - how to wake up another event loop
		1067
		1068	Async watchers are provided by EV, but have little use in perl directly,
		1069	as perl neither supports threads running in parallel nor direct access to
		1070	signal handlers or other contexts where they could be of value.
		1071
		1072	It is, however, possible to use them from the XS level.
		1073
		1074	Please see the libev documentation for further details.
		1075
		1076	=over 4
		1077
		1078	=item $w = EV::async $callback
		1079
		1080	=item $w = EV::async_ns $callback
		1081
		1082	=item $w->send
		1083
		1084	=item $bool = $w->async_pending
		1085
		1086	=back
		1087
		1088
		1089	=head1 PERL SIGNALS
		1090
		1091	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1092	with EV is as the same as any other C library: Perl-signals will only be
		1093	handled when Perl runs, which means your signal handler might be invoked
		1094	only the next time an event callback is invoked.
		1095
		1096	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1097	ensure proper operations with regards to other event watchers.
		1098
		1099	If you cannot do this for whatever reason, you can also force a watcher
		1100	to be called on every event loop iteration by installing a C<EV::check>
		1101	watcher:
		1102
		1103	my $async_check = EV::check sub { };
		1104
		1105	This ensures that perl gets into control for a short time to handle any
		1106	pending signals, and also ensures (slightly) slower overall operation.
		1107
		1108	=head1 ITHREADS
		1109
		1110	Ithreads are not supported by this module in any way. Perl pseudo-threads
		1111	is evil stuff and must die. Real threads as provided by Coro are fully
		1112	supported (and enhanced support is available via L<Coro::EV>).
		1113
		1114	=head1 FORK
		1115
		1116	Most of the "improved" event delivering mechanisms of modern operating
		1117	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1118	not supported and usually destructive). Libev makes it possible to work
		1119	around this by having a function that recreates the kernel state after
		1120	fork in the child.
		1121
		1122	On non-win32 platforms, this module requires the pthread_atfork
		1123	functionality to do this automatically for you. This function is quite
		1124	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1125	negligible, because everything the function currently does is set a flag
		1126	that is checked only when the event loop gets used the next time, so when
		1127	you do fork but not use EV, the overhead is minimal.
		1128
		1129	On win32, there is no notion of fork so all this doesn't apply, of course.
298		1130
299	=cut	1131	=cut
300		1132
301	our $DIED = sub {	1133	our $DIED = sub {
302	warn "EV: error in callback (ignoring): $@";	1134	warn "EV: error in callback (ignoring): $@";
303	};	1135	};
304		1136
305	our $NPRI = 4;	1137	default_loop
306	our $BASE = init;	1138	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
307	priority_init $NPRI;
308
309	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
310		1139
311	1;	1140	1;
312		1141
313	=head1 SEE ALSO	1142	=head1 SEE ALSO
314		1143
315	L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>.	1144	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
316	L<EV::AnyEvent>.	1145	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1146	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1147	event-loop agnostic and portable event driven programming.
317		1148
318	=head1 AUTHOR	1149	=head1 AUTHOR
319		1150
320	Marc Lehmann <schmorp@schmorp.de>	1151	Marc Lehmann <schmorp@schmorp.de>
321	http://home.schmorp.de/	1152	http://home.schmorp.de/
322		1153
323	=cut	1154	=cut
324		1155

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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 1.123 by root, Sun Aug 9 13:30:41 2009 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 1.123 by root, Sun Aug 9 13:30:41 2009 UTC