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

Comparing EV/EV.pm (file contents):
Revision 1.50 by root, Sat Nov 24 08:42:38 2007 UTC vs.
Revision 1.138 by root, Sun May 6 16:30:27 2012 UTC

…		…
2		2
3	EV - perl interface to libev, a high performance full-featured event loop	3	EV - perl interface to libev, a high performance full-featured event loop
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use EV;	7	use EV;
		8
		9	# TIMERS
		10
		11	my $w = EV::timer 2, 0, sub {
		12	warn "is called after 2s";
		13	};
		14
		15	my $w = EV::timer 2, 2, sub {
		16	warn "is called roughly every 2s (repeat = 2)";
		17	};
		18
		19	undef $w; # destroy event watcher again
		20
		21	my $w = EV::periodic 0, 60, 0, sub {
		22	warn "is called every minute, on the minute, exactly";
		23	};
		24
		25	# IO
		26
		27	my $w = EV::io *STDIN, EV::READ, sub {
		28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
		29	warn "stdin is readable, you entered: ", <STDIN>;
		30	};
		31
		32	# SIGNALS
		33
		34	my $w = EV::signal 'QUIT', sub {
		35	warn "sigquit received\n";
		36	};
		37
		38	# CHILD/PID STATUS CHANGES
8		39
9	# TIMERS	40	my $w = EV::child 666, 0, sub {
		41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
		43	};
10		44
11	my $w = EV::timer 2, 0, sub {	45	# STAT CHANGES
12	warn "is called after 2s";	46	my $w = EV::stat "/etc/passwd", 10, sub {
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
39
40	my $w = EV::child 666, sub {
41	my ($w, $revents) = @_;	47	my ($w, $revents) = @_;
42	my $status = $w->rstatus;	48	warn $w->path, " has changed somehow.\n";
43	};	49	};
44		50
45	# MAINLOOP	51	# MAINLOOP
46	EV::loop; # loop until EV::unloop is called or all watchers stop	52	EV::run; # loop until EV::unloop is called or all watchers stop
47	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::run EV::RUN_ONCE; # block until at least one event could be handled
48	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
		55
		56	=head1 BEFORE YOU START USING THIS MODULE
		57
		58	If you only need timer, I/O, signal, child and idle watchers and not the
		59	advanced functionality of this module, consider using L<AnyEvent> instead,
		60	specifically the simplified API described in L<AE>.
		61
		62	When used with EV as backend, the L<AE> API is as fast as the native L<EV>
		63	API, but your programs/modules will still run with many other event loops.
49		64
50	=head1 DESCRIPTION	65	=head1 DESCRIPTION
51		66
52	This module provides an interface to libev	67	This module provides an interface to libev
53	(L<http://software.schmorp.de/pkg/libev.html>).	68	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		69	below is comprehensive, one might also consult the documentation of
		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.
		75
		76	This module is very fast and scalable. It is actually so fast that you
		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.
54		116
55	=cut	117	=cut
56		118
57	package EV;	119	package EV;
58		120
59	use strict;	121	use common::sense;
60		122
61	BEGIN {	123	BEGIN {
62	our $VERSION = '1.2';	124	our $VERSION = '4.11';
63	use XSLoader;	125	use XSLoader;
64	XSLoader::load "EV", $VERSION;	126	XSLoader::load "EV", $VERSION;
65	}	127	}
66		128
67	@EV::IO::ISA =	129	@EV::IO::ISA =
68	@EV::Timer::ISA =	130	@EV::Timer::ISA =
69	@EV::Periodic::ISA =	131	@EV::Periodic::ISA =
70	@EV::Signal::ISA =	132	@EV::Signal::ISA =
		133	@EV::Child::ISA =
		134	@EV::Stat::ISA =
71	@EV::Idle::ISA =	135	@EV::Idle::ISA =
72	@EV::Prepare::ISA =	136	@EV::Prepare::ISA =
73	@EV::Check::ISA =	137	@EV::Check::ISA =
74	@EV::Child::ISA = "EV::Watcher";	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->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
75		207
76	=head1 BASIC INTERFACE	208	=head1 BASIC INTERFACE
77		209
78	=over 4	210	=over 4
79		211
80	=item $EV::DIED	212	=item $EV::DIED
81		213
82	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
83	throws an exception (with $@ containing thr error). The default prints an	215	throws an exception (with $@ containing the error). The default prints an
84	informative message and continues.	216	informative message and continues.
85		217
86	If this callback throws an exception it will be silently ignored.	218	If this callback throws an exception it will be silently ignored.
87		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
88	=item $time = EV::time	234	=item $time = EV::time
89		235
90	Returns the current time in (fractional) seconds since the epoch.	236	Returns the current time in (fractional) seconds since the epoch.
91		237
92	=item $time = EV::now	238	=item $time = EV::now
93		239
		240	=item $time = $loop->now
		241
94	Returns the time the last event loop iteration has been started. This	242	Returns the time the last event loop iteration has been started. This
95	is the time that (relative) timers are based on, and refering to it is	243	is the time that (relative) timers are based on, and referring to it is
96	usually faster then calling EV::time.	244	usually faster then calling EV::time.
97		245
98	=item $method = EV::method	246	=item EV::now_update
99		247
		248	=item $loop->now_update
		249
		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>.
		253
		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.
		257
		258	=item EV::suspend
		259
		260	=item $loop->suspend
		261
		262	=item EV::resume
		263
		264	=item $loop->resume
		265
		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.
		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 = $loop->backend
		291
100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	292	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
101	or EV::METHOD_EPOLL).	293	or EV::BACKEND_EPOLL).
102		294
103	=item EV::loop [$flags]	295	=item $active = EV::run [$flags]
		296
		297	=item $active = $loop->run ([$flags])
104		298
105	Begin checking for events and calling callbacks. It returns when a	299	Begin checking for events and calling callbacks. It returns when a
106	callback calls EV::unloop.	300	callback calls EV::unloop or the flasg are nonzero (in which case the
		301	return value is true) or when there are no active watchers which reference
		302	the loop (keepalive is true), in which case the return value will be
		303	false. The returnv alue can generally be interpreted as "if true, there is
		304	more work left to do".
107		305
108	The $flags argument can be one of the following:	306	The $flags argument can be one of the following:
109		307
110	0 as above	308	0 as above
111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	309	EV::RUN_ONCE block at most once (wait, but do not loop)
112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	310	EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
113		311
114	=item EV::unloop [$how]	312	=item EV::break [$how]
115		313
		314	=item $loop->break ([$how])
		315
116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the	316	When called with no arguments or an argument of EV::BREAK_ONE, makes the
117	innermost call to EV::loop return.	317	innermost call to EV::loop return.
118		318
119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as	319	When called with an argument of EV::BREAK_ALL, all calls to EV::loop will
120	fast as possible.	320	return as fast as possible.
		321
		322	When called with an argument of EV::BREAK_CANCEL, any pending break will
		323	be cancelled.
		324
		325	=item $count = EV::iteration
		326
		327	=item $count = $loop->iteration
		328
		329	Return the number of times the event loop has polled for new
		330	events. Sometimes useful as a generation counter.
121		331
122	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)	332	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		333
		334	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
123		335
124	This function rolls together an I/O and a timer watcher for a single	336	This function rolls together an I/O and a timer watcher for a single
125	one-shot event without the need for managing a watcher object.	337	one-shot event without the need for managing a watcher object.
126		338
127	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>	339	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
…		…
133	If timeout is C<undef> or negative, then there will be no	345	If timeout is C<undef> or negative, then there will be no
134	timeout. Otherwise a EV::timer with this value will be started.	346	timeout. Otherwise a EV::timer with this value will be started.
135		347
136	When an error occurs or either the timeout or I/O watcher triggers, then	348	When an error occurs or either the timeout or I/O watcher triggers, then
137	the callback will be called with the received event set (in general	349	the callback will be called with the received event set (in general
138	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,	350	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
139	C<EV::WRITE> and C<EV::TIMEOUT>).	351	C<EV::WRITE> and C<EV::TIMER>).
140		352
141	EV::once doesn't return anything: the watchers stay active till either	353	EV::once doesn't return anything: the watchers stay active till either
142	of them triggers, then they will be stopped and freed, and the callback	354	of them triggers, then they will be stopped and freed, and the callback
143	invoked.	355	invoked.
144		356
145	=back	357	=item EV::feed_fd_event $fd, $revents
146		358
147	=head2 WATCHER	359	=item $loop->feed_fd_event ($fd, $revents)
		360
		361	Feed an event on a file descriptor into EV. EV will react to this call as
		362	if the readyness notifications specified by C<$revents> (a combination of
		363	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		364
		365	=item EV::feed_signal_event $signal
		366
		367	Feed a signal event into the default loop. EV will react to this call as
		368	if the signal specified by C<$signal> had occured.
		369
		370	=item EV::feed_signal $signal
		371
		372	Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
		373	regardless of which loop has registered the signal, and is mainly useful
		374	fro custom signal implementations.
		375
		376	=item EV::set_io_collect_interval $time
		377
		378	=item $loop->set_io_collect_interval ($time)
		379
		380	=item EV::set_timeout_collect_interval $time
		381
		382	=item $loop->set_timeout_collect_interval ($time)
		383
		384	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		385	wait interval for timer events. See the libev documentation at
		386	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		387	(locally installed as F<EV::libev>) for a more detailed discussion.
		388
		389	=item $count = EV::pending_count
		390
		391	=item $count = $loop->pending_count
		392
		393	Returns the number of currently pending watchers.
		394
		395	=item EV::invoke_pending
		396
		397	=item $loop->invoke_pending
		398
		399	Invoke all currently pending watchers.
		400
		401	=back
		402
		403
		404	=head1 WATCHER OBJECTS
148		405
149	A watcher is an object that gets created to record your interest in some	406	A watcher is an object that gets created to record your interest in some
150	event. For instance, if you want to wait for STDIN to become readable, you	407	event. For instance, if you want to wait for STDIN to become readable, you
151	would create an EV::io watcher for that:	408	would create an EV::io watcher for that:
152		409
153	my $watcher = EV::io *STDIN, EV::READ, sub {	410	my $watcher = EV::io *STDIN, EV::READ, sub {
154	my ($watcher, $revents) = @_;	411	my ($watcher, $revents) = @_;
155	warn "yeah, STDIN should not be readable without blocking!\n"	412	warn "yeah, STDIN should now be readable without blocking!\n"
156	};	413	};
157		414
158	All watchers can be active (waiting for events) or inactive (paused). Only	415	All watchers can be active (waiting for events) or inactive (paused). Only
159	active watchers will have their callbacks invoked. All callbacks will be	416	active watchers will have their callbacks invoked. All callbacks will be
160	called with at least two arguments: the watcher and a bitmask of received	417	called with at least two arguments: the watcher and a bitmask of received
161	events.	418	events.
162		419
163	Each watcher type has its associated bit in revents, so you can use the	420	Each watcher type has its associated bit in revents, so you can use the
164	same callback for multiple watchers. The event mask is named after the	421	same callback for multiple watchers. The event mask is named after the
165	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	422	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
166	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	423	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
167	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	424	(which can set both EV::READ and EV::WRITE bits).
168	uses EV::TIMEOUT).
169		425
170	In the rare case where one wants to create a watcher but not start it at	426	In the rare case where one wants to create a watcher but not start it at
171	the same time, each constructor has a variant with a trailing C<_ns> in	427	the same time, each constructor has a variant with a trailing C<_ns> in
172	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.	428	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
173		429
…		…
177		433
178	Also, all methods changing some aspect of a watcher (->set, ->priority,	434	Also, all methods changing some aspect of a watcher (->set, ->priority,
179	->fh and so on) automatically stop and start it again if it is active,	435	->fh and so on) automatically stop and start it again if it is active,
180	which means pending events get lost.	436	which means pending events get lost.
181		437
182	=head2 WATCHER TYPES	438	=head2 COMMON WATCHER METHODS
183		439
184	Now lets move to the existing watcher types and asociated methods.	440	This section lists methods common to all watchers.
185
186	The following methods are available for all watchers. Then followes a
187	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
188	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
189	any type-specific methods (if any).
190		441
191	=over 4	442	=over 4
192		443
193	=item $w->start	444	=item $w->start
194		445
…		…
198		449
199	=item $w->stop	450	=item $w->stop
200		451
201	Stop a watcher if it is active. Also clear any pending events (events that	452	Stop a watcher if it is active. Also clear any pending events (events that
202	have been received but that didn't yet result in a callback invocation),	453	have been received but that didn't yet result in a callback invocation),
203	regardless of wether the watcher was active or not.	454	regardless of whether the watcher was active or not.
204		455
205	=item $bool = $w->is_active	456	=item $bool = $w->is_active
206		457
207	Returns true if the watcher is active, false otherwise.	458	Returns true if the watcher is active, false otherwise.
208		459
…		…
238	The default priority of any newly-created watcher is 0.	489	The default priority of any newly-created watcher is 0.
239		490
240	Note that the priority semantics have not yet been fleshed out and are	491	Note that the priority semantics have not yet been fleshed out and are
241	subject to almost certain change.	492	subject to almost certain change.
242		493
243	=item $w->trigger ($revents)	494	=item $w->invoke ($revents)
244		495
245	Call the callback now with the given event mask.	496	Call the callback now with the given event mask.
		497
		498	=item $w->feed_event ($revents)
		499
		500	Feed some events on this watcher into EV. EV will react to this call as if
		501	the watcher had received the given C<$revents> mask.
		502
		503	=item $revents = $w->clear_pending
		504
		505	If the watcher is pending, this function clears its pending status and
		506	returns its C<$revents> bitset (as if its callback was invoked). If the
		507	watcher isn't pending it does nothing and returns C<0>.
246		508
247	=item $previous_state = $w->keepalive ($bool)	509	=item $previous_state = $w->keepalive ($bool)
248		510
249	Normally, C<EV::loop> will return when there are no active watchers	511	Normally, C<EV::loop> will return when there are no active watchers
250	(which is a "deadlock" because no progress can be made anymore). This is	512	(which is a "deadlock" because no progress can be made anymore). This is
251	convinient because it allows you to start your watchers (and your jobs),	513	convenient because it allows you to start your watchers (and your jobs),
252	call C<EV::loop> once and when it returns you know that all your jobs are	514	call C<EV::loop> once and when it returns you know that all your jobs are
253	finished (or they forgot to register some watchers for their task :).	515	finished (or they forgot to register some watchers for their task :).
254		516
255	Sometimes, however, this gets in your way, for example when you the module	517	Sometimes, however, this gets in your way, for example when the module
256	that calls C<EV::loop> (usually the main program) is not the same module	518	that calls C<EV::loop> (usually the main program) is not the same module
257	as a long-living watcher (for example a DNS client module written by	519	as a long-living watcher (for example a DNS client module written by
258	somebody else even). Then you might want any outstanding requests to be	520	somebody else even). Then you might want any outstanding requests to be
259	handled, but you would not want to keep C<EV::loop> from returning just	521	handled, but you would not want to keep C<EV::loop> from returning just
260	because you happen to have this long-running UDP port watcher.	522	because you happen to have this long-running UDP port watcher.
261		523
262	In this case you can clear the keepalive status, which means that even	524	In this case you can clear the keepalive status, which means that even
263	though your watcher is active, it won't keep C<EV::loop> from returning.	525	though your watcher is active, it won't keep C<EV::loop> from returning.
264		526
265	The initial value for keepalive is true (enabled), and you cna change it	527	The initial value for keepalive is true (enabled), and you can change it
266	any time.	528	any time.
267		529
268	Example: Register an IO watcher for some UDP socket but do not keep the	530	Example: Register an I/O watcher for some UDP socket but do not keep the
269	event loop from running just because of that watcher.	531	event loop from running just because of that watcher.
270		532
271	my $udp_socket = ...	533	my $udp_socket = ...
272	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };	534	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
273	$udp_watcher->keepalive (0);	535	$udp_watcher->keepalive (0);
274		536
		537	=item $loop = $w->loop
		538
		539	Return the loop that this watcher is attached to.
		540
		541	=back
		542
		543
		544	=head1 WATCHER TYPES
		545
		546	Each of the following subsections describes a single watcher type.
		547
		548	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		549
		550	=over 4
		551
275	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	552	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
276		553
277	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	554	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
278		555
		556	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		557
		558	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		559
279	As long as the returned watcher object is alive, call the C<$callback>	560	As long as the returned watcher object is alive, call the C<$callback>
280	when the events specified in C<$eventmask>.	561	when at least one of events specified in C<$eventmask> occurs.
281		562
282	The $eventmask can be one or more of these constants ORed together:	563	The $eventmask can be one or more of these constants ORed together:
283		564
284	EV::READ wait until read() wouldn't block anymore	565	EV::READ wait until read() wouldn't block anymore
285	EV::WRITE wait until write() wouldn't block anymore	566	EV::WRITE wait until write() wouldn't block anymore
…		…
301		582
302	=item $old_eventmask = $w->events ($new_eventmask)	583	=item $old_eventmask = $w->events ($new_eventmask)
303		584
304	Returns the previously set event mask and optionally set a new one.	585	Returns the previously set event mask and optionally set a new one.
305		586
		587	=back
		588
		589
		590	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		591
		592	=over 4
306		593
307	=item $w = EV::timer $after, $repeat, $callback	594	=item $w = EV::timer $after, $repeat, $callback
308		595
309	=item $w = EV::timer_ns $after, $repeat, $callback	596	=item $w = EV::timer_ns $after, $repeat, $callback
310		597
311	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	598	=item $w = $loop->timer ($after, $repeat, $callback)
312	the timer will be restarted (with the $repeat value as $after) after the	599
313	callback returns.	600	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		601
		602	Calls the callback after C<$after> seconds (which may be fractional). If
		603	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		604	value as $after) after the callback returns.
314		605
315	This means that the callback would be called roughly after C<$after>	606	This means that the callback would be called roughly after C<$after>
316	seconds, and then every C<$repeat> seconds. The timer does his best not	607	seconds, and then every C<$repeat> seconds. The timer does his best not
317	to drift, but it will not invoke the timer more often then once per event	608	to drift, but it will not invoke the timer more often then once per event
318	loop iteration, and might drift in other cases. If that isn't acceptable,	609	loop iteration, and might drift in other cases. If that isn't acceptable,
…		…
324		615
325	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	616	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
326		617
327	=item $w->set ($after, $repeat)	618	=item $w->set ($after, $repeat)
328		619
329	Reconfigures the watcher, see the constructor above for details. Can be at	620	Reconfigures the watcher, see the constructor above for details. Can be called at
330	any time.	621	any time.
331		622
332	=item $w->again	623	=item $w->again
333		624
334	Similar to the C<start> method, but has special semantics for repeating timers:	625	Similar to the C<start> method, but has special semantics for repeating timers:
…		…
345	This behaviour is useful when you have a timeout for some IO	636	This behaviour is useful when you have a timeout for some IO
346	operation. You create a timer object with the same value for C<$after> and	637	operation. You create a timer object with the same value for C<$after> and
347	C<$repeat>, and then, in the read/write watcher, run the C<again> method	638	C<$repeat>, and then, in the read/write watcher, run the C<again> method
348	on the timeout.	639	on the timeout.
349		640
		641	=back
		642
		643
		644	=head3 PERIODIC WATCHERS - to cron or not to cron?
		645
		646	=over 4
350		647
351	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	648	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
352		649
353	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	650	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		651
		652	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		653
		654	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
354		655
355	Similar to EV::timer, but is not based on relative timeouts but on	656	Similar to EV::timer, but is not based on relative timeouts but on
356	absolute times. Apart from creating "simple" timers that trigger "at" the	657	absolute times. Apart from creating "simple" timers that trigger "at" the
357	specified time, it can also be used for non-drifting absolute timers and	658	specified time, it can also be used for non-drifting absolute timers and
358	more complex, cron-like, setups that are not adversely affected by time	659	more complex, cron-like, setups that are not adversely affected by time
…		…
368	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	669	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
369	will not adjust when a time jump occurs, that is, if it is to be run	670	will not adjust when a time jump occurs, that is, if it is to be run
370	at January 1st 2011 then it will run when the system time reaches or	671	at January 1st 2011 then it will run when the system time reaches or
371	surpasses this time.	672	surpasses this time.
372		673
373	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	674	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
374		675
375	In this mode the watcher will always be scheduled to time out at the	676	In this mode the watcher will always be scheduled to time out at the
376	next C<$at + N * $interval> time (for some integer N) and then repeat,	677	next C<$at + N * $interval> time (for some integer N) and then repeat,
377	regardless of any time jumps.	678	regardless of any time jumps.
378		679
…		…
396	time the periodic watcher gets scheduled, the reschedule callback	697	time the periodic watcher gets scheduled, the reschedule callback
397	($reschedule_cb) will be called with the watcher as first, and the current	698	($reschedule_cb) will be called with the watcher as first, and the current
398	time as second argument.	699	time as second argument.
399		700
400	I<This callback MUST NOT stop or destroy this or any other periodic	701	I<This callback MUST NOT stop or destroy this or any other periodic
401	watcher, ever>. If you need to stop it, return 1e30 and stop it	702	watcher, ever, and MUST NOT call any event loop functions or methods>. If
402	afterwards.	703	you need to stop it, return 1e30 and stop it afterwards. You may create
		704	and start a C<EV::prepare> watcher for this task.
403		705
404	It must return the next time to trigger, based on the passed time value	706	It must return the next time to trigger, based on the passed time value
405	(that is, the lowest time value larger than to the second argument). It	707	(that is, the lowest time value larger than or equal to to the second
406	will usually be called just before the callback will be triggered, but	708	argument). It will usually be called just before the callback will be
407	might be called at other times, too.	709	triggered, but might be called at other times, too.
408		710
409	This can be used to create very complex timers, such as a timer that	711	This can be used to create very complex timers, such as a timer that
410	triggers on each midnight, local time (actually 24 hours after the last	712	triggers on each midnight, local time (actually 24 hours after the last
411	midnight, to keep the example simple. If you know a way to do it correctly	713	midnight, to keep the example simple. If you know a way to do it correctly
412	in about the same space (without requiring elaborate modules), drop me a	714	in about the same space (without requiring elaborate modules), drop me a
…		…
426		728
427	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	729	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
428		730
429	=item $w->set ($at, $interval, $reschedule_cb)	731	=item $w->set ($at, $interval, $reschedule_cb)
430		732
431	Reconfigures the watcher, see the constructor above for details. Can be at	733	Reconfigures the watcher, see the constructor above for details. Can be called at
432	any time.	734	any time.
433		735
434	=item $w->again	736	=item $w->again
435		737
436	Simply stops and starts the watcher again.	738	Simply stops and starts the watcher again.
437		739
		740	=item $time = $w->at
		741
		742	Return the time that the watcher is expected to trigger next.
		743
		744	=back
		745
		746
		747	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		748
		749	=over 4
438		750
439	=item $w = EV::signal $signal, $callback	751	=item $w = EV::signal $signal, $callback
440		752
441	=item $w = EV::signal_ns $signal, $callback	753	=item $w = EV::signal_ns $signal, $callback
442		754
		755	=item $w = $loop->signal ($signal, $callback)
		756
		757	=item $w = $loop->signal_ns ($signal, $callback)
		758
443	Call the callback when $signal is received (the signal can be specified	759	Call the callback when $signal is received (the signal can be specified by
444	by number or by name, just as with kill or %SIG).	760	number or by name, just as with C<kill> or C<%SIG>).
		761
		762	Only one event loop can grab a given signal - attempting to grab the same
		763	signal from two EV loops will crash the program immediately or cause data
		764	corruption.
445		765
446	EV will grab the signal for the process (the kernel only allows one	766	EV will grab the signal for the process (the kernel only allows one
447	component to receive a signal at a time) when you start a signal watcher,	767	component to receive a signal at a time) when you start a signal watcher,
448	and removes it again when you stop it. Perl does the same when you	768	and removes it again when you stop it. Perl does the same when you
449	add/remove callbacks to %SIG, so watch out.	769	add/remove callbacks to C<%SIG>, so watch out.
450		770
451	You can have as many signal watchers per signal as you want.	771	You can have as many signal watchers per signal as you want.
452		772
453	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	773	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
454		774
455	=item $w->set ($signal)	775	=item $w->set ($signal)
456		776
457	Reconfigures the watcher, see the constructor above for details. Can be at	777	Reconfigures the watcher, see the constructor above for details. Can be
458	any time.	778	called at any time.
459		779
460	=item $current_signum = $w->signal	780	=item $current_signum = $w->signal
461		781
462	=item $old_signum = $w->signal ($new_signal)	782	=item $old_signum = $w->signal ($new_signal)
463		783
464	Returns the previously set signal (always as a number not name) and	784	Returns the previously set signal (always as a number not name) and
465	optionally set a new one.	785	optionally set a new one.
466		786
		787	=back
467		788
		789
		790	=head3 CHILD WATCHERS - watch out for process status changes
		791
		792	=over 4
		793
468	=item $w = EV::child $pid, $callback	794	=item $w = EV::child $pid, $trace, $callback
469		795
470	=item $w = EV::child_ns $pid, $callback	796	=item $w = EV::child_ns $pid, $trace, $callback
		797
		798	=item $w = $loop->child ($pid, $trace, $callback)
		799
		800	=item $w = $loop->child_ns ($pid, $trace, $callback)
471		801
472	Call the callback when a status change for pid C<$pid> (or any pid	802	Call the callback when a status change for pid C<$pid> (or any pid
473	if C<$pid> is 0) has been received. More precisely: when the process	803	if C<$pid> is 0) has been received (a status change happens when the
		804	process terminates or is killed, or, when trace is true, additionally when
		805	it is stopped or continued). More precisely: when the process receives
474	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	806	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
475	changed/zombie children and call the callback.	807	changed/zombie children and call the callback.
476		808
477	You can access both status and pid by using the C<rstatus> and C<rpid>	809	It is valid (and fully supported) to install a child watcher after a child
478	methods on the watcher object.	810	has exited but before the event loop has started its next iteration (for
		811	example, first you C<fork>, then the new child process might exit, and
		812	only then do you install a child watcher in the parent for the new pid).
479		813
		814	You can access both exit (or tracing) status and pid by using the
		815	C<rstatus> and C<rpid> methods on the watcher object.
		816
480	You can have as many pid watchers per pid as you want.	817	You can have as many pid watchers per pid as you want, they will all be
		818	called.
481		819
482	The C<child_ns> variant doesn't start (activate) the newly created watcher.	820	The C<child_ns> variant doesn't start (activate) the newly created watcher.
483		821
484	=item $w->set ($pid)	822	=item $w->set ($pid, $trace)
485		823
486	Reconfigures the watcher, see the constructor above for details. Can be at	824	Reconfigures the watcher, see the constructor above for details. Can be called at
487	any time.	825	any time.
488		826
489	=item $current_pid = $w->pid	827	=item $current_pid = $w->pid
490
491	=item $old_pid = $w->pid ($new_pid)
492		828
493	Returns the previously set process id and optionally set a new one.	829	Returns the previously set process id and optionally set a new one.
494		830
495	=item $exit_status = $w->rstatus	831	=item $exit_status = $w->rstatus
496		832
…		…
500	=item $pid = $w->rpid	836	=item $pid = $w->rpid
501		837
502	Return the pid of the awaited child (useful when you have installed a	838	Return the pid of the awaited child (useful when you have installed a
503	watcher for all pids).	839	watcher for all pids).
504		840
		841	=back
		842
		843
		844	=head3 STAT WATCHERS - did the file attributes just change?
		845
		846	=over 4
		847
		848	=item $w = EV::stat $path, $interval, $callback
		849
		850	=item $w = EV::stat_ns $path, $interval, $callback
		851
		852	=item $w = $loop->stat ($path, $interval, $callback)
		853
		854	=item $w = $loop->stat_ns ($path, $interval, $callback)
		855
		856	Call the callback when a file status change has been detected on
		857	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		858	to "path does not exist" is a status change like any other.
		859
		860	The C<$interval> is a recommended polling interval for systems where
		861	OS-supported change notifications don't exist or are not supported. If
		862	you use C<0> then an unspecified default is used (which is highly
		863	recommended!), which is to be expected to be around five seconds usually.
		864
		865	This watcher type is not meant for massive numbers of stat watchers,
		866	as even with OS-supported change notifications, this can be
		867	resource-intensive.
		868
		869	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		870
		871	=item ... = $w->stat
		872
		873	This call is very similar to the perl C<stat> built-in: It stats (using
		874	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		875	well as EV's idea of the current stat values) to the values found.
		876
		877	In scalar context, a boolean is return indicating success or failure of
		878	the stat. In list context, the same 13-value list as with stat is returned
		879	(except that the blksize and blocks fields are not reliable).
		880
		881	In the case of an error, errno is set to C<ENOENT> (regardless of the
		882	actual error value) and the C<nlink> value is forced to zero (if the stat
		883	was successful then nlink is guaranteed to be non-zero).
		884
		885	See also the next two entries for more info.
		886
		887	=item ... = $w->attr
		888
		889	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		890	the values most recently detected by EV. See the next entry for more info.
		891
		892	=item ... = $w->prev
		893
		894	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		895	the previous set of values, before the change.
		896
		897	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		898	to the values found I<before> a change was detected, while C<< $w->attr >>
		899	returns the values found leading to the change detection. The difference (if any)
		900	between C<prev> and C<attr> is what triggered the callback.
		901
		902	If you did something to the filesystem object and do not want to trigger
		903	yet another change, you can call C<stat> to update EV's idea of what the
		904	current attributes are.
		905
		906	=item $w->set ($path, $interval)
		907
		908	Reconfigures the watcher, see the constructor above for details. Can be
		909	called at any time.
		910
		911	=item $current_path = $w->path
		912
		913	=item $old_path = $w->path ($new_path)
		914
		915	Returns the previously set path and optionally set a new one.
		916
		917	=item $current_interval = $w->interval
		918
		919	=item $old_interval = $w->interval ($new_interval)
		920
		921	Returns the previously set interval and optionally set a new one. Can be
		922	used to query the actual interval used.
		923
		924	=back
		925
		926
		927	=head3 IDLE WATCHERS - when you've got nothing better to do...
		928
		929	=over 4
505		930
506	=item $w = EV::idle $callback	931	=item $w = EV::idle $callback
507		932
508	=item $w = EV::idle_ns $callback	933	=item $w = EV::idle_ns $callback
509		934
510	Call the callback when there are no pending io, timer/periodic, signal or	935	=item $w = $loop->idle ($callback)
511	child events, i.e. when the process is idle.	936
		937	=item $w = $loop->idle_ns ($callback)
		938
		939	Call the callback when there are no other pending watchers of the same or
		940	higher priority (excluding check, prepare and other idle watchers of the
		941	same or lower priority, of course). They are called idle watchers because
		942	when the watcher is the highest priority pending event in the process, the
		943	process is considered to be idle at that priority.
		944
		945	If you want a watcher that is only ever called when I<no> other events are
		946	outstanding you have to set the priority to C<EV::MINPRI>.
512		947
513	The process will not block as long as any idle watchers are active, and	948	The process will not block as long as any idle watchers are active, and
514	they will be called repeatedly until stopped.	949	they will be called repeatedly until stopped.
515		950
		951	For example, if you have idle watchers at priority C<0> and C<1>, and
		952	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		953	and the I/O watcher will always run when ready. Only when the idle watcher
		954	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		955	pending with the C<0>-priority idle watcher be invoked.
		956
516	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	957	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
517		958
		959	=back
		960
		961
		962	=head3 PREPARE WATCHERS - customise your event loop!
		963
		964	=over 4
518		965
519	=item $w = EV::prepare $callback	966	=item $w = EV::prepare $callback
520		967
521	=item $w = EV::prepare_ns $callback	968	=item $w = EV::prepare_ns $callback
		969
		970	=item $w = $loop->prepare ($callback)
		971
		972	=item $w = $loop->prepare_ns ($callback)
522		973
523	Call the callback just before the process would block. You can still	974	Call the callback just before the process would block. You can still
524	create/modify any watchers at this point.	975	create/modify any watchers at this point.
525		976
526	See the EV::check watcher, below, for explanations and an example.	977	See the EV::check watcher, below, for explanations and an example.
527		978
528	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	979	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
529		980
		981	=back
		982
		983
		984	=head3 CHECK WATCHERS - customise your event loop even more!
		985
		986	=over 4
530		987
531	=item $w = EV::check $callback	988	=item $w = EV::check $callback
532		989
533	=item $w = EV::check_ns $callback	990	=item $w = EV::check_ns $callback
		991
		992	=item $w = $loop->check ($callback)
		993
		994	=item $w = $loop->check_ns ($callback)
534		995
535	Call the callback just after the process wakes up again (after it has	996	Call the callback just after the process wakes up again (after it has
536	gathered events), but before any other callbacks have been invoked.	997	gathered events), but before any other callbacks have been invoked.
537		998
538	This is used to integrate other event-based software into the EV	999	This can be used to integrate other event-based software into the EV
539	mainloop: You register a prepare callback and in there, you create io and	1000	mainloop: You register a prepare callback and in there, you create io and
540	timer watchers as required by the other software. Here is a real-world	1001	timer watchers as required by the other software. Here is a real-world
541	example of integrating Net::SNMP (with some details left out):	1002	example of integrating Net::SNMP (with some details left out):
542		1003
543	our @snmp_watcher;	1004	our @snmp_watcher;
…		…
548	or return;	1009	or return;
549		1010
550	# make the dispatcher handle any outstanding stuff	1011	# make the dispatcher handle any outstanding stuff
551	... not shown	1012	... not shown
552		1013
553	# create an IO watcher for each and every socket	1014	# create an I/O watcher for each and every socket
554	@snmp_watcher = (	1015	@snmp_watcher = (
555	(map { EV::io $_, EV::READ, sub { } }	1016	(map { EV::io $_, EV::READ, sub { } }
556	keys %{ $dispatcher->{_descriptors} }),	1017	keys %{ $dispatcher->{_descriptors} }),
557		1018
558	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]	1019	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
…		…
573	# make the dispatcher handle any new stuff	1034	# make the dispatcher handle any new stuff
574	... not shown	1035	... not shown
575	};	1036	};
576		1037
577	The callbacks of the created watchers will not be called as the watchers	1038	The callbacks of the created watchers will not be called as the watchers
578	are destroyed before this cna happen (remember EV::check gets called	1039	are destroyed before this can happen (remember EV::check gets called
579	first).	1040	first).
580		1041
581	The C<check_ns> variant doesn't start (activate) the newly created watcher.	1042	The C<check_ns> variant doesn't start (activate) the newly created watcher.
582		1043
583	=back	1044	=item EV::CHECK constant issues
584		1045
		1046	Like all other watcher types, there is a bitmask constant for use in
		1047	C<$revents> and other places. The C<EV::CHECK> is special as it has
		1048	the same name as the C<CHECK> sub called by Perl. This doesn't cause
		1049	big issues on newer perls (beginning with 5.8.9), but it means thatthe
		1050	constant must be I<inlined>, i.e. runtime calls will not work. That means
		1051	that as long as you always C<use EV> and then C<EV::CHECK> you are on the
		1052	safe side.
		1053
		1054	=back
		1055
		1056
		1057	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		1058
		1059	Fork watchers are called when a C<fork ()> was detected. The invocation
		1060	is done before the event loop blocks next and before C<check> watchers
		1061	are being called, and only in the child after the fork.
		1062
		1063	=over 4
		1064
		1065	=item $w = EV::fork $callback
		1066
		1067	=item $w = EV::fork_ns $callback
		1068
		1069	=item $w = $loop->fork ($callback)
		1070
		1071	=item $w = $loop->fork_ns ($callback)
		1072
		1073	Call the callback before the event loop is resumed in the child process
		1074	after a fork.
		1075
		1076	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		1077
		1078	=back
		1079
		1080
		1081	=head3 EMBED WATCHERS - when one backend isn't enough...
		1082
		1083	This is a rather advanced watcher type that lets you embed one event loop
		1084	into another (currently only IO events are supported in the embedded
		1085	loop, other types of watchers might be handled in a delayed or incorrect
		1086	fashion and must not be used).
		1087
		1088	See the libev documentation at
		1089	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1090	(locally installed as F<EV::libev>) for more details.
		1091
		1092	In short, this watcher is most useful on BSD systems without working
		1093	kqueue to still be able to handle a large number of sockets:
		1094
		1095	my $socket_loop;
		1096
		1097	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1098	if (
		1099	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1100	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1101	) {
		1102	# use kqueue for sockets
		1103	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1104	}
		1105
		1106	# use the default loop otherwise
		1107	$socket_loop \|\|= EV::default_loop;
		1108
		1109	=over 4
		1110
		1111	=item $w = EV::embed $otherloop[, $callback]
		1112
		1113	=item $w = EV::embed_ns $otherloop[, $callback]
		1114
		1115	=item $w = $loop->embed ($otherloop[, $callback])
		1116
		1117	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1118
		1119	Call the callback when the embedded event loop (C<$otherloop>) has any
		1120	I/O activity. The C<$callback> is optional: if it is missing, then the
		1121	embedded event loop will be managed automatically (which is recommended),
		1122	otherwise you have to invoke C<sweep> yourself.
		1123
		1124	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1125
		1126	=back
		1127
		1128	=head3 ASYNC WATCHERS - how to wake up another event loop
		1129
		1130	Async watchers are provided by EV, but have little use in perl directly,
		1131	as perl neither supports threads running in parallel nor direct access to
		1132	signal handlers or other contexts where they could be of value.
		1133
		1134	It is, however, possible to use them from the XS level.
		1135
		1136	Please see the libev documentation for further details.
		1137
		1138	=over 4
		1139
		1140	=item $w = EV::async $callback
		1141
		1142	=item $w = EV::async_ns $callback
		1143
		1144	=item $w = $loop->async ($callback)
		1145
		1146	=item $w = $loop->async_ns ($callback)
		1147
		1148	=item $w->send
		1149
		1150	=item $bool = $w->async_pending
		1151
		1152	=back
		1153
		1154	=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
		1155
		1156	Cleanup watchers are not supported on the Perl level, they can only be
		1157	used via XS currently.
		1158
		1159
		1160	=head1 PERL SIGNALS
		1161
		1162	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1163	with EV is as the same as any other C library: Perl-signals will only be
		1164	handled when Perl runs, which means your signal handler might be invoked
		1165	only the next time an event callback is invoked.
		1166
		1167	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1168	ensure proper operations with regards to other event watchers.
		1169
		1170	If you cannot do this for whatever reason, you can also force a watcher
		1171	to be called on every event loop iteration by installing a C<EV::check>
		1172	watcher:
		1173
		1174	my $async_check = EV::check sub { };
		1175
		1176	This ensures that perl gets into control for a short time to handle any
		1177	pending signals, and also ensures (slightly) slower overall operation.
		1178
585	=head1 THREADS	1179	=head1 ITHREADS
586		1180
587	Threads are not supported by this module in any way. Perl pseudo-threads	1181	Ithreads are not supported by this module in any way. Perl pseudo-threads
588	is evil stuff and must die. As soon as Perl gains real threads I will work	1182	is evil stuff and must die. Real threads as provided by Coro are fully
589	on thread support for it.	1183	supported (and enhanced support is available via L<Coro::EV>).
590		1184
591	=head1 FORK	1185	=head1 FORK
592		1186
593	Most of the "improved" event delivering mechanisms of modern operating	1187	Most of the "improved" event delivering mechanisms of modern operating
594	systems have quite a few problems with fork(2) (to put it bluntly: it is	1188	systems have quite a few problems with fork(2) (to put it bluntly: it is
…		…
610	our $DIED = sub {	1204	our $DIED = sub {
611	warn "EV: error in callback (ignoring): $@";	1205	warn "EV: error in callback (ignoring): $@";
612	};	1206	};
613		1207
614	default_loop	1208	default_loop
615	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1209	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
616		1210
617	1;	1211	1;
618		1212
619	=head1 SEE ALSO	1213	=head1 SEE ALSO
620		1214
621	L<EV::DNS>.	1215	L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
		1216	(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
		1217	loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
		1218	integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1219	event-loop agnostic and portable event driven programming.
622		1220
623	=head1 AUTHOR	1221	=head1 AUTHOR
624		1222
625	Marc Lehmann <schmorp@schmorp.de>	1223	Marc Lehmann <schmorp@schmorp.de>
626	http://home.schmorp.de/	1224	http://home.schmorp.de/
627		1225
628	=cut	1226	=cut
629		1227

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Comparing EV/EV.pm (file contents): Revision 1.50 by root, Sat Nov 24 08:42:38 2007 UTC vs. Revision 1.138 by root, Sun May 6 16:30:27 2012 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.50 by root, Sat Nov 24 08:42:38 2007 UTC vs.
Revision 1.138 by root, Sun May 6 16:30:27 2012 UTC