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

Comparing EV/EV.pm (file contents):
Revision 1.25 by root, Fri Nov 2 22:18:49 2007 UTC vs.
Revision 1.116 by root, Sat Jun 13 15:11:54 2009 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 $w = EV::stat "/etc/passwd", 10, sub {
		47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
13	};	49	};
14		50
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::periodic 0, 60, sub {
22	warn "is called every minute, on the minute, exactly";
23	};
24
25	# IO
26
27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $revents) = @_; # all callbacks get the watcher object 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	my $w = EV::signal 3, sub {
39	warn "sigquit received (this is GNU/Linux, right?)\n";
40	};
41
42	# CHILD/PID STATUS CHANGES
43
44	my $w = EV::child 666, sub {
45	my ($w, $revents, $status) = @_;
46	};
47
48	# MAINLOOP	51	# MAINLOOP
49	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
50	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
51	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
52		55
53	=head1 DESCRIPTION	56	=head1 DESCRIPTION
54		57
55	This module provides an interface to libev	58	This module provides an interface to libev
56	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of
		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.
		66
		67	This module is very fast and scalable. It is actually so fast that you
		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.
57		76
58	=cut	77	=cut
59		78
60	package EV;	79	package EV;
61		80
		81	no warnings;
62	use strict;	82	use strict;
63		83
64	BEGIN {	84	BEGIN {
65	our $VERSION = '0.5';	85	our $VERSION = '3.6';
66	use XSLoader;	86	use XSLoader;
67	XSLoader::load "EV", $VERSION;	87	XSLoader::load "EV", $VERSION;
68	}	88	}
69		89
70	@EV::Io::ISA =	90	@EV::IO::ISA =
71	@EV::Timer::ISA =	91	@EV::Timer::ISA =
72	@EV::Periodic::ISA =	92	@EV::Periodic::ISA =
73	@EV::Signal::ISA =	93	@EV::Signal::ISA =
		94	@EV::Child::ISA =
		95	@EV::Stat::ISA =
74	@EV::Idle::ISA =	96	@EV::Idle::ISA =
75	@EV::Prepare::ISA =	97	@EV::Prepare::ISA =
76	@EV::Check::ISA =	98	@EV::Check::ISA =
77	@EV::Child::ISA = "EV::Watcher";	99	@EV::Embed::ISA =
		100	@EV::Fork::ISA =
		101	@EV::Async::ISA =
		102	"EV::Watcher";
		103
		104	@EV::Loop::Default::ISA = "EV::Loop";
		105
		106	=head1 EVENT LOOPS
		107
		108	EV supports multiple event loops: There is a single "default event loop"
		109	that can handle everything including signals and child watchers, and any
		110	number of "dynamic event loops" that can use different backends (with
		111	various limitations), but no child and signal watchers.
		112
		113	You do not have to do anything to create the default event loop: When
		114	the module is loaded a suitable backend is selected on the premise of
		115	selecting a working backend (which for example rules out kqueue on most
		116	BSDs). Modules should, unless they have "special needs" always use the
		117	default loop as this is fastest (perl-wise), best supported by other
		118	modules (e.g. AnyEvent or Coro) and most portable event loop.
		119
		120	For specific programs you can create additional event loops dynamically.
		121
		122	If you want to take advantage of kqueue (which often works properly for
		123	sockets only) even though the default loop doesn't enable it, you can
		124	I<embed> a kqueue loop into the default loop: running the default loop
		125	will then also service the kqueue loop to some extent. See the example in
		126	the section about embed watchers for an example on how to achieve that.
		127
		128	=over 4
		129
		130	=item $loop = new EV::Loop [$flags]
		131
		132	Create a new event loop as per the specified flags. Please refer to
		133	the C<ev_loop_new ()> function description in the libev documentation
		134	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
		135	or locally-installed as F<EV::libev> manpage) for more info.
		136
		137	The loop will automatically be destroyed when it is no longer referenced
		138	by any watcher and the loop object goes out of scope.
		139
		140	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		141	is recommended, as only the default event loop is protected by this
		142	module. If you I<are> embedding this loop in the default loop, this is not
		143	necessary, as C<EV::embed> automatically does the right thing on fork.
		144
		145	=item $loop->loop_fork
		146
		147	Must be called after a fork in the child, before entering or continuing
		148	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		149	this function automatically, at some performance loss (refer to the libev
		150	documentation).
		151
		152	=item $loop->loop_verify
		153
		154	Calls C<ev_verify> to make internal consistency checks (for debugging
		155	libev) and abort the program if any data structures were found to be
		156	corrupted.
		157
		158	=item $loop = EV::default_loop [$flags]
		159
		160	Return the default loop (which is a singleton object). Since this module
		161	already creates the default loop with default flags, specifying flags here
		162	will not have any effect unless you destroy the default loop first, which
		163	isn't supported. So in short: don't do it, and if you break it, you get to
		164	keep the pieces.
		165
		166	=back
		167
78		168
79	=head1 BASIC INTERFACE	169	=head1 BASIC INTERFACE
80		170
81	=over 4	171	=over 4
82		172
83	=item $EV::DIED	173	=item $EV::DIED
84		174
85	Must contain a reference to a function that is called when a callback	175	Must contain a reference to a function that is called when a callback
86	throws an exception (with $@ containing thr error). The default prints an	176	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	177	informative message and continues.
88		178
89	If this callback throws an exception it will be silently ignored.	179	If this callback throws an exception it will be silently ignored.
90		180
		181	=item $flags = EV::supported_backends
		182
		183	=item $flags = EV::recommended_backends
		184
		185	=item $flags = EV::embeddable_backends
		186
		187	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		188	instance of EV, the set of recommended backends (supposed to be good) for
		189	this platform and the set of embeddable backends (see EMBED WATCHERS).
		190
		191	=item EV::sleep $seconds
		192
		193	Block the process for the given number of (fractional) seconds.
		194
91	=item $time = EV::time	195	=item $time = EV::time
92		196
93	Returns the current time in (fractional) seconds since the epoch.	197	Returns the current time in (fractional) seconds since the epoch.
94		198
95	=item $time = EV::now	199	=item $time = EV::now
96		200
		201	=item $time = $loop->now
		202
97	Returns the time the last event loop iteration has been started. This	203	Returns the time the last event loop iteration has been started. This
98	is the time that (relative) timers are based on, and refering to it is	204	is the time that (relative) timers are based on, and referring to it is
99	usually faster then calling EV::time.	205	usually faster then calling EV::time.
100		206
101	=item $method = EV::ev_method	207	=item EV::now_update
102		208
		209	=item $loop->now_update
		210
		211	Establishes the current time by querying the kernel, updating the time
		212	returned by C<EV::now> in the progress. This is a costly operation and
		213	is usually done automatically within C<EV::loop>.
		214
		215	This function is rarely useful, but when some event callback runs for a
		216	very long time without entering the event loop, updating libev's idea of
		217	the current time is a good idea.
		218
		219	=item EV::suspend
		220
		221	=item $loop->suspend
		222
		223	=item EV::resume
		224
		225	=item $loop->resume
		226
		227	These two functions suspend and resume a loop, for use when the loop is
		228	not used for a while and timeouts should not be processed.
		229
		230	A typical use case would be an interactive program such as a game: When
		231	the user presses C<^Z> to suspend the game and resumes it an hour later it
		232	would be best to handle timeouts as if no time had actually passed while
		233	the program was suspended. This can be achieved by calling C<suspend>
		234	in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
		235	C<resume> directly afterwards to resume timer processing.
		236
		237	Effectively, all C<timer> watchers will be delayed by the time spend
		238	between C<suspend> and C<resume>, and all C<periodic> watchers
		239	will be rescheduled (that is, they will lose any events that would have
		240	occured while suspended).
		241
		242	After calling C<suspend> you B<must not> call I<any> function on the given
		243	loop other than C<resume>, and you B<must not> call C<resume>
		244	without a previous call to C<suspend>.
		245
		246	Calling C<suspend>/C<resume> has the side effect of updating the event
		247	loop time (see C<now_update>).
		248
		249	=item $backend = EV::backend
		250
		251	=item $backend = $loop->backend
		252
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	253	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
104	or EV::METHOD_EPOLL).	254	or EV::BACKEND_EPOLL).
105		255
106	=item EV::loop [$flags]	256	=item EV::loop [$flags]
107		257
		258	=item $loop->loop ([$flags])
		259
108	Begin checking for events and calling callbacks. It returns when a	260	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	261	callback calls EV::unloop.
110		262
111	The $flags argument can be one of the following:	263	The $flags argument can be one of the following:
112		264
113	0 as above	265	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	266	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	267	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		268
117	=item EV::loop_done [$how]	269	=item EV::unloop [$how]
118		270
		271	=item $loop->unloop ([$how])
		272
119	When called with no arguments or an argument of 1, makes the innermost	273	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	274	innermost call to EV::loop return.
121		275
122	When called with an agrument of 2, all calls to EV::loop will return as	276	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	277	fast as possible.
124		278
125	=back	279	=item $count = EV::loop_count
126		280
127	=head2 WATCHER	281	=item $count = $loop->loop_count
		282
		283	Return the number of times the event loop has polled for new
		284	events. Sometimes useful as a generation counter.
		285
		286	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		287
		288	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		289
		290	This function rolls together an I/O and a timer watcher for a single
		291	one-shot event without the need for managing a watcher object.
		292
		293	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		294	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		295	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		296	you do not want to wait for some I/O event, specify C<undef> for
		297	C<$fh_or_undef> and C<0> for C<$events>).
		298
		299	If timeout is C<undef> or negative, then there will be no
		300	timeout. Otherwise a EV::timer with this value will be started.
		301
		302	When an error occurs or either the timeout or I/O watcher triggers, then
		303	the callback will be called with the received event set (in general
		304	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		305	C<EV::WRITE> and C<EV::TIMEOUT>).
		306
		307	EV::once doesn't return anything: the watchers stay active till either
		308	of them triggers, then they will be stopped and freed, and the callback
		309	invoked.
		310
		311	=item EV::feed_fd_event ($fd, $revents)
		312
		313	=item $loop->feed_fd_event ($fd, $revents)
		314
		315	Feed an event on a file descriptor into EV. EV will react to this call as
		316	if the readyness notifications specified by C<$revents> (a combination of
		317	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		318
		319	=item EV::feed_signal_event ($signal)
		320
		321	Feed a signal event into EV. EV will react to this call as if the signal
		322	specified by C<$signal> had occured.
		323
		324	=item EV::set_io_collect_interval $time
		325
		326	=item $loop->set_io_collect_interval ($time)
		327
		328	=item EV::set_timeout_collect_interval $time
		329
		330	=item $loop->set_timeout_collect_interval ($time)
		331
		332	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		333	wait interval for timer events. See the libev documentation at
		334	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		335	(locally installed as F<EV::libev>) for a more detailed discussion.
		336
		337	=back
		338
		339
		340	=head1 WATCHER OBJECTS
128		341
129	A watcher is an object that gets created to record your interest in some	342	A watcher is an object that gets created to record your interest in some
130	event. For instance, if you want to wait for STDIN to become readable, you	343	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	344	would create an EV::io watcher for that:
132		345
133	my $watcher = EV::io *STDIN, EV::READ, sub {	346	my $watcher = EV::io *STDIN, EV::READ, sub {
134	my ($watcher, $revents) = @_;	347	my ($watcher, $revents) = @_;
135	warn "yeah, STDIN should not be readable without blocking!\n"	348	warn "yeah, STDIN should now be readable without blocking!\n"
136	};	349	};
137		350
138	All watchers can be active (waiting for events) or inactive (paused). Only	351	All watchers can be active (waiting for events) or inactive (paused). Only
139	active watchers will have their callbacks invoked. All callbacks will be	352	active watchers will have their callbacks invoked. All callbacks will be
140	called with at least two arguments: the watcher and a bitmask of received	353	called with at least two arguments: the watcher and a bitmask of received
141	events.	354	events.
142		355
143	Each watcher type has its associated bit in revents, so you can use the	356	Each watcher type has its associated bit in revents, so you can use the
144	same callback for multiple watchers. The event mask is named after the	357	same callback for multiple watchers. The event mask is named after the
145	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	358	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
146	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	359	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
147	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	360	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	361	uses EV::TIMEOUT).
149		362
150	In the rare case where one wants to create a watcher but not start it at	363	In the rare case where one wants to create a watcher but not start it at
151	the same time, each constructor has a variant with a trailing C<_ns> in	364	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
157		370
158	Also, all methods changing some aspect of a watcher (->set, ->priority,	371	Also, all methods changing some aspect of a watcher (->set, ->priority,
159	->fh and so on) automatically stop and start it again if it is active,	372	->fh and so on) automatically stop and start it again if it is active,
160	which means pending events get lost.	373	which means pending events get lost.
161		374
162	=head2 WATCHER TYPES	375	=head2 COMMON WATCHER METHODS
163		376
164	Now lets move to the existing watcher types and asociated methods.	377	This section lists methods common to all watchers.
165
166	The following methods are available for all watchers. Then followes a
167	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
168	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
169	any type-specific methods (if any).
170		378
171	=over 4	379	=over 4
172		380
173	=item $w->start	381	=item $w->start
174		382
…		…
178		386
179	=item $w->stop	387	=item $w->stop
180		388
181	Stop a watcher if it is active. Also clear any pending events (events that	389	Stop a watcher if it is active. Also clear any pending events (events that
182	have been received but that didn't yet result in a callback invocation),	390	have been received but that didn't yet result in a callback invocation),
183	regardless of wether the watcher was active or not.	391	regardless of whether the watcher was active or not.
184		392
185	=item $bool = $w->is_active	393	=item $bool = $w->is_active
186		394
187	Returns true if the watcher is active, false otherwise.	395	Returns true if the watcher is active, false otherwise.
		396
		397	=item $current_data = $w->data
		398
		399	=item $old_data = $w->data ($new_data)
		400
		401	Queries a freely usable data scalar on the watcher and optionally changes
		402	it. This is a way to associate custom data with a watcher:
		403
		404	my $w = EV::timer 60, 0, sub {
		405	warn $_[0]->data;
		406	};
		407	$w->data ("print me!");
188		408
189	=item $current_cb = $w->cb	409	=item $current_cb = $w->cb
190		410
191	=item $old_cb = $w->cb ($new_cb)	411	=item $old_cb = $w->cb ($new_cb)
192		412
…		…
201	watchers with higher priority will be invoked first. The valid range of	421	watchers with higher priority will be invoked first. The valid range of
202	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	422	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
203	-2). If the priority is outside this range it will automatically be	423	-2). If the priority is outside this range it will automatically be
204	normalised to the nearest valid priority.	424	normalised to the nearest valid priority.
205		425
206	The default priority of any newly-created weatcher is 0.	426	The default priority of any newly-created watcher is 0.
207		427
		428	Note that the priority semantics have not yet been fleshed out and are
		429	subject to almost certain change.
		430
208	=item $w->trigger ($revents)	431	=item $w->invoke ($revents)
209		432
210	Call the callback now with the given event mask.	433	Call the callback now with the given event mask.
211		434
		435	=item $w->feed_event ($revents)
		436
		437	Feed some events on this watcher into EV. EV will react to this call as if
		438	the watcher had received the given C<$revents> mask.
		439
		440	=item $revents = $w->clear_pending
		441
		442	If the watcher is pending, this function clears its pending status and
		443	returns its C<$revents> bitset (as if its callback was invoked). If the
		444	watcher isn't pending it does nothing and returns C<0>.
		445
		446	=item $previous_state = $w->keepalive ($bool)
		447
		448	Normally, C<EV::loop> will return when there are no active watchers
		449	(which is a "deadlock" because no progress can be made anymore). This is
		450	convinient because it allows you to start your watchers (and your jobs),
		451	call C<EV::loop> once and when it returns you know that all your jobs are
		452	finished (or they forgot to register some watchers for their task :).
		453
		454	Sometimes, however, this gets in your way, for example when the module
		455	that calls C<EV::loop> (usually the main program) is not the same module
		456	as a long-living watcher (for example a DNS client module written by
		457	somebody else even). Then you might want any outstanding requests to be
		458	handled, but you would not want to keep C<EV::loop> from returning just
		459	because you happen to have this long-running UDP port watcher.
		460
		461	In this case you can clear the keepalive status, which means that even
		462	though your watcher is active, it won't keep C<EV::loop> from returning.
		463
		464	The initial value for keepalive is true (enabled), and you can change it
		465	any time.
		466
		467	Example: Register an I/O watcher for some UDP socket but do not keep the
		468	event loop from running just because of that watcher.
		469
		470	my $udp_socket = ...
		471	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		472	$udp_watcher->keepalive (0);
		473
		474	=item $loop = $w->loop
		475
		476	Return the loop that this watcher is attached to.
		477
		478	=back
		479
		480
		481	=head1 WATCHER TYPES
		482
		483	Each of the following subsections describes a single watcher type.
		484
		485	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		486
		487	=over 4
212		488
213	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	489	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
214		490
215	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	491	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
216		492
		493	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		494
		495	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		496
217	As long as the returned watcher object is alive, call the C<$callback>	497	As long as the returned watcher object is alive, call the C<$callback>
218	when the events specified in C<$eventmask>.	498	when at least one of events specified in C<$eventmask> occurs.
219		499
220	The $eventmask can be one or more of these constants ORed together:	500	The $eventmask can be one or more of these constants ORed together:
221		501
222	EV::READ wait until read() wouldn't block anymore	502	EV::READ wait until read() wouldn't block anymore
223	EV::WRITE wait until write() wouldn't block anymore	503	EV::WRITE wait until write() wouldn't block anymore
…		…
239		519
240	=item $old_eventmask = $w->events ($new_eventmask)	520	=item $old_eventmask = $w->events ($new_eventmask)
241		521
242	Returns the previously set event mask and optionally set a new one.	522	Returns the previously set event mask and optionally set a new one.
243		523
		524	=back
		525
		526
		527	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		528
		529	=over 4
244		530
245	=item $w = EV::timer $after, $repeat, $callback	531	=item $w = EV::timer $after, $repeat, $callback
246		532
247	=item $w = EV::timer_ns $after, $repeat, $callback	533	=item $w = EV::timer_ns $after, $repeat, $callback
248		534
249	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	535	=item $w = $loop->timer ($after, $repeat, $callback)
250	the timer will be restarted (with the $repeat value as $after) after the	536
251	callback returns.	537	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		538
		539	Calls the callback after C<$after> seconds (which may be fractional). If
		540	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		541	value as $after) after the callback returns.
252		542
253	This means that the callback would be called roughly after C<$after>	543	This means that the callback would be called roughly after C<$after>
254	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	544	seconds, and then every C<$repeat> seconds. The timer does his best not
255	callback processing is not taken into account, so the timer will slowly	545	to drift, but it will not invoke the timer more often then once per event
256	drift. If that isn't acceptable, look at EV::periodic.	546	loop iteration, and might drift in other cases. If that isn't acceptable,
		547	look at EV::periodic, which can provide long-term stable timers.
257		548
258	The timer is based on a monotonic clock, that is if somebody is sitting	549	The timer is based on a monotonic clock, that is, if somebody is sitting
259	in front of the machine while the timer is running and changes the system	550	in front of the machine while the timer is running and changes the system
260	clock, the timer will nevertheless run (roughly) the same time.	551	clock, the timer will nevertheless run (roughly) the same time.
261		552
262	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	553	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
263		554
264	=item $w->set ($after, $repeat)	555	=item $w->set ($after, $repeat)
265		556
266	Reconfigures the watcher, see the constructor above for details. Can be at	557	Reconfigures the watcher, see the constructor above for details. Can be called at
267	any time.	558	any time.
268		559
269	=item $w->again	560	=item $w->again
270		561
271	Similar to the C<start> method, but has special semantics for repeating timers:	562	Similar to the C<start> method, but has special semantics for repeating timers:
		563
		564	If the timer is active and non-repeating, it will be stopped.
272		565
273	If the timer is active and repeating, reset the timeout to occur	566	If the timer is active and repeating, reset the timeout to occur
274	C<$repeat> seconds after now.	567	C<$repeat> seconds after now.
275		568
276	If the timer is active and non-repeating, it will be stopped.
277
278	If the timer is in active and repeating, start it.	569	If the timer is inactive and repeating, start it using the repeat value.
279		570
280	Otherwise do nothing.	571	Otherwise do nothing.
281		572
282	This behaviour is useful when you have a timeout for some IO	573	This behaviour is useful when you have a timeout for some IO
283	operation. You create a timer object with the same value for C<$after> and	574	operation. You create a timer object with the same value for C<$after> and
284	C<$repeat>, and then, in the read/write watcher, run the C<again> method	575	C<$repeat>, and then, in the read/write watcher, run the C<again> method
285	on the timeout.	576	on the timeout.
286		577
		578	=back
287		579
		580
		581	=head3 PERIODIC WATCHERS - to cron or not to cron?
		582
		583	=over 4
		584
288	=item $w = EV::periodic $at, $interval, $callback	585	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
289		586
290	=item $w = EV::periodic_ns $at, $interval, $callback	587	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
291		588
292	Similar to EV::timer, but the time is given as an absolute point in time	589	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
293	(C<$at>), plus an optional C<$interval>.
294		590
295	If the C<$interval> is zero, then the callback will be called at the time	591	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
296	C<$at> if that is in the future, or as soon as possible if it is in the
297	past. It will not automatically repeat.
298		592
299	If the C<$interval> is nonzero, then the watcher will always be scheduled	593	Similar to EV::timer, but is not based on relative timeouts but on
300	to time out at the next C<$at + N * $interval> time.	594	absolute times. Apart from creating "simple" timers that trigger "at" the
		595	specified time, it can also be used for non-drifting absolute timers and
		596	more complex, cron-like, setups that are not adversely affected by time
		597	jumps (i.e. when the system clock is changed by explicit date -s or other
		598	means such as ntpd). It is also the most complex watcher type in EV.
301		599
302	This can be used to schedule a callback to run at very regular intervals,	600	It has three distinct "modes":
303	as long as the processing time is less then the interval (otherwise	601
304	obviously events will be skipped).	602	=over 4
		603
		604	=item * absolute timer ($interval = $reschedule_cb = 0)
		605
		606	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		607	will not adjust when a time jump occurs, that is, if it is to be run
		608	at January 1st 2011 then it will run when the system time reaches or
		609	surpasses this time.
		610
		611	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
		612
		613	In this mode the watcher will always be scheduled to time out at the
		614	next C<$at + N * $interval> time (for some integer N) and then repeat,
		615	regardless of any time jumps.
		616
		617	This can be used to create timers that do not drift with respect to system
		618	time:
		619
		620	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		621
		622	That doesn't mean there will always be 3600 seconds in between triggers,
		623	but only that the the clalback will be called when the system time shows a
		624	full hour (UTC).
305		625
306	Another way to think about it (for the mathematically inclined) is that	626	Another way to think about it (for the mathematically inclined) is that
307	EV::periodic will try to run the callback at the next possible time where	627	EV::periodic will try to run the callback in this mode at the next
308	C<$time = $at (mod $interval)>, regardless of any time jumps.	628	possible time where C<$time = $at (mod $interval)>, regardless of any time
		629	jumps.
309		630
310	This periodic timer is based on "wallclock time", that is, if the clock	631	=item * manual reschedule mode ($reschedule_cb = coderef)
311	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	632
312	the specified time. This means it will never drift (it might jitter, but	633	In this mode $interval and $at are both being ignored. Instead, each
313	it will not drift).	634	time the periodic watcher gets scheduled, the reschedule callback
		635	($reschedule_cb) will be called with the watcher as first, and the current
		636	time as second argument.
		637
		638	I<This callback MUST NOT stop or destroy this or any other periodic
		639	watcher, ever, and MUST NOT call any event loop functions or methods>. If
		640	you need to stop it, return 1e30 and stop it afterwards. You may create
		641	and start a C<EV::prepare> watcher for this task.
		642
		643	It must return the next time to trigger, based on the passed time value
		644	(that is, the lowest time value larger than or equal to to the second
		645	argument). It will usually be called just before the callback will be
		646	triggered, but might be called at other times, too.
		647
		648	This can be used to create very complex timers, such as a timer that
		649	triggers on each midnight, local time (actually 24 hours after the last
		650	midnight, to keep the example simple. If you know a way to do it correctly
		651	in about the same space (without requiring elaborate modules), drop me a
		652	note :):
		653
		654	my $daily = EV::periodic 0, 0, sub {
		655	my ($w, $now) = @_;
		656
		657	use Time::Local ();
		658	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		659	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		660	}, sub {
		661	print "it's midnight or likely shortly after, now\n";
		662	};
		663
		664	=back
314		665
315	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	666	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
316		667
317	=item $w->set ($at, $interval)	668	=item $w->set ($at, $interval, $reschedule_cb)
318		669
319	Reconfigures the watcher, see the constructor above for details. Can be at	670	Reconfigures the watcher, see the constructor above for details. Can be called at
320	any time.	671	any time.
321		672
		673	=item $w->again
		674
		675	Simply stops and starts the watcher again.
		676
		677	=item $time = $w->at
		678
		679	Return the time that the watcher is expected to trigger next.
		680
		681	=back
		682
		683
		684	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		685
		686	=over 4
322		687
323	=item $w = EV::signal $signal, $callback	688	=item $w = EV::signal $signal, $callback
324		689
325	=item $w = EV::signal_ns $signal, $callback	690	=item $w = EV::signal_ns $signal, $callback
326		691
327	Call the callback when $signal is received (the signal can be specified	692	Call the callback when $signal is received (the signal can be specified by
328	by number or by name, just as with kill or %SIG).	693	number or by name, just as with C<kill> or C<%SIG>).
329		694
330	EV will grab the signal for the process (the kernel only allows one	695	EV will grab the signal for the process (the kernel only allows one
331	component to receive a signal at a time) when you start a signal watcher,	696	component to receive a signal at a time) when you start a signal watcher,
332	and removes it again when you stop it. Perl does the same when you	697	and removes it again when you stop it. Perl does the same when you
333	add/remove callbacks to %SIG, so watch out.	698	add/remove callbacks to C<%SIG>, so watch out.
334		699
335	You can have as many signal watchers per signal as you want.	700	You can have as many signal watchers per signal as you want.
336		701
337	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	702	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
338		703
339	=item $w->set ($signal)	704	=item $w->set ($signal)
340		705
341	Reconfigures the watcher, see the constructor above for details. Can be at	706	Reconfigures the watcher, see the constructor above for details. Can be
342	any time.	707	called at any time.
343		708
344	=item $current_signum = $w->signal	709	=item $current_signum = $w->signal
345		710
346	=item $old_signum = $w->signal ($new_signal)	711	=item $old_signum = $w->signal ($new_signal)
347		712
348	Returns the previously set signal (always as a number not name) and	713	Returns the previously set signal (always as a number not name) and
349	optionally set a new one.	714	optionally set a new one.
350		715
		716	=back
351		717
		718
		719	=head3 CHILD WATCHERS - watch out for process status changes
		720
		721	=over 4
		722
352	=item $w = EV::child $pid, $callback	723	=item $w = EV::child $pid, $trace, $callback
353		724
354	=item $w = EV::child_ns $pid, $callback	725	=item $w = EV::child_ns $pid, $trace, $callback
		726
		727	=item $w = $loop->child ($pid, $trace, $callback)
		728
		729	=item $w = $loop->child_ns ($pid, $trace, $callback)
355		730
356	Call the callback when a status change for pid C<$pid> (or any pid	731	Call the callback when a status change for pid C<$pid> (or any pid
357	if C<$pid> is 0) has been received. More precisely: when the process	732	if C<$pid> is 0) has been received (a status change happens when the
		733	process terminates or is killed, or, when trace is true, additionally when
		734	it is stopped or continued). More precisely: when the process receives
358	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	735	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
359	changed/zombie children and call the callback.	736	changed/zombie children and call the callback.
360		737
361	Unlike all other callbacks, this callback will be called with an	738	It is valid (and fully supported) to install a child watcher after a child
362	additional third argument which is the exit status. See the C<waitpid>	739	has exited but before the event loop has started its next iteration (for
363	function for details.	740	example, first you C<fork>, then the new child process might exit, and
		741	only then do you install a child watcher in the parent for the new pid).
364		742
		743	You can access both exit (or tracing) status and pid by using the
		744	C<rstatus> and C<rpid> methods on the watcher object.
		745
365	You can have as many pid watchers per pid as you want.	746	You can have as many pid watchers per pid as you want, they will all be
		747	called.
366		748
367	The C<child_ns> variant doesn't start (activate) the newly created watcher.	749	The C<child_ns> variant doesn't start (activate) the newly created watcher.
368		750
369	=item $w->set ($pid)	751	=item $w->set ($pid, $trace)
370		752
371	Reconfigures the watcher, see the constructor above for details. Can be at	753	Reconfigures the watcher, see the constructor above for details. Can be called at
372	any time.	754	any time.
373		755
374	=item $current_pid = $w->pid	756	=item $current_pid = $w->pid
375		757
376	=item $old_pid = $w->pid ($new_pid)
377
378	Returns the previously set process id and optionally set a new one.	758	Returns the previously set process id and optionally set a new one.
379		759
		760	=item $exit_status = $w->rstatus
		761
		762	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		763	in perlfunc).
		764
		765	=item $pid = $w->rpid
		766
		767	Return the pid of the awaited child (useful when you have installed a
		768	watcher for all pids).
		769
		770	=back
		771
		772
		773	=head3 STAT WATCHERS - did the file attributes just change?
		774
		775	=over 4
		776
		777	=item $w = EV::stat $path, $interval, $callback
		778
		779	=item $w = EV::stat_ns $path, $interval, $callback
		780
		781	=item $w = $loop->stat ($path, $interval, $callback)
		782
		783	=item $w = $loop->stat_ns ($path, $interval, $callback)
		784
		785	Call the callback when a file status change has been detected on
		786	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		787	to "path does not exist" is a status change like any other.
		788
		789	The C<$interval> is a recommended polling interval for systems where
		790	OS-supported change notifications don't exist or are not supported. If
		791	you use C<0> then an unspecified default is used (which is highly
		792	recommended!), which is to be expected to be around five seconds usually.
		793
		794	This watcher type is not meant for massive numbers of stat watchers,
		795	as even with OS-supported change notifications, this can be
		796	resource-intensive.
		797
		798	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		799
		800	=item ... = $w->stat
		801
		802	This call is very similar to the perl C<stat> built-in: It stats (using
		803	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		804	well as EV's idea of the current stat values) to the values found.
		805
		806	In scalar context, a boolean is return indicating success or failure of
		807	the stat. In list context, the same 13-value list as with stat is returned
		808	(except that the blksize and blocks fields are not reliable).
		809
		810	In the case of an error, errno is set to C<ENOENT> (regardless of the
		811	actual error value) and the C<nlink> value is forced to zero (if the stat
		812	was successful then nlink is guaranteed to be non-zero).
		813
		814	See also the next two entries for more info.
		815
		816	=item ... = $w->attr
		817
		818	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		819	the values most recently detected by EV. See the next entry for more info.
		820
		821	=item ... = $w->prev
		822
		823	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		824	the previous set of values, before the change.
		825
		826	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		827	to the values found I<before> a change was detected, while C<< $w->attr >>
		828	returns the values found leading to the change detection. The difference (if any)
		829	between C<prev> and C<attr> is what triggered the callback.
		830
		831	If you did something to the filesystem object and do not want to trigger
		832	yet another change, you can call C<stat> to update EV's idea of what the
		833	current attributes are.
		834
		835	=item $w->set ($path, $interval)
		836
		837	Reconfigures the watcher, see the constructor above for details. Can be
		838	called at any time.
		839
		840	=item $current_path = $w->path
		841
		842	=item $old_path = $w->path ($new_path)
		843
		844	Returns the previously set path and optionally set a new one.
		845
		846	=item $current_interval = $w->interval
		847
		848	=item $old_interval = $w->interval ($new_interval)
		849
		850	Returns the previously set interval and optionally set a new one. Can be
		851	used to query the actual interval used.
		852
		853	=back
		854
		855
		856	=head3 IDLE WATCHERS - when you've got nothing better to do...
		857
		858	=over 4
380		859
381	=item $w = EV::idle $callback	860	=item $w = EV::idle $callback
382		861
383	=item $w = EV::idle_ns $callback	862	=item $w = EV::idle_ns $callback
384		863
385	Call the callback when there are no pending io, timer/periodic, signal or	864	=item $w = $loop->idle ($callback)
386	child events, i.e. when the process is idle.	865
		866	=item $w = $loop->idle_ns ($callback)
		867
		868	Call the callback when there are no other pending watchers of the same or
		869	higher priority (excluding check, prepare and other idle watchers of the
		870	same or lower priority, of course). They are called idle watchers because
		871	when the watcher is the highest priority pending event in the process, the
		872	process is considered to be idle at that priority.
		873
		874	If you want a watcher that is only ever called when I<no> other events are
		875	outstanding you have to set the priority to C<EV::MINPRI>.
387		876
388	The process will not block as long as any idle watchers are active, and	877	The process will not block as long as any idle watchers are active, and
389	they will be called repeatedly until stopped.	878	they will be called repeatedly until stopped.
390		879
		880	For example, if you have idle watchers at priority C<0> and C<1>, and
		881	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		882	and the I/O watcher will always run when ready. Only when the idle watcher
		883	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		884	pending with the C<0>-priority idle watcher be invoked.
		885
391	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	886	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
392		887
		888	=back
		889
		890
		891	=head3 PREPARE WATCHERS - customise your event loop!
		892
		893	=over 4
393		894
394	=item $w = EV::prepare $callback	895	=item $w = EV::prepare $callback
395		896
396	=item $w = EV::prepare_ns $callback	897	=item $w = EV::prepare_ns $callback
		898
		899	=item $w = $loop->prepare ($callback)
		900
		901	=item $w = $loop->prepare_ns ($callback)
397		902
398	Call the callback just before the process would block. You can still	903	Call the callback just before the process would block. You can still
399	create/modify any watchers at this point.	904	create/modify any watchers at this point.
400		905
401	See the EV::check watcher, below, for explanations and an example.	906	See the EV::check watcher, below, for explanations and an example.
402		907
403	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	908	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
404		909
		910	=back
		911
		912
		913	=head3 CHECK WATCHERS - customise your event loop even more!
		914
		915	=over 4
405		916
406	=item $w = EV::check $callback	917	=item $w = EV::check $callback
407		918
408	=item $w = EV::check_ns $callback	919	=item $w = EV::check_ns $callback
		920
		921	=item $w = $loop->check ($callback)
		922
		923	=item $w = $loop->check_ns ($callback)
409		924
410	Call the callback just after the process wakes up again (after it has	925	Call the callback just after the process wakes up again (after it has
411	gathered events), but before any other callbacks have been invoked.	926	gathered events), but before any other callbacks have been invoked.
412		927
413	This is used to integrate other event-based software into the EV	928	This is used to integrate other event-based software into the EV
…		…
421	# do nothing unless active	936	# do nothing unless active
422	$dispatcher->{_event_queue_h}	937	$dispatcher->{_event_queue_h}
423	or return;	938	or return;
424		939
425	# make the dispatcher handle any outstanding stuff	940	# make the dispatcher handle any outstanding stuff
		941	... not shown
426		942
427	# create an IO watcher for each and every socket	943	# create an I/O watcher for each and every socket
428	@snmp_watcher = (	944	@snmp_watcher = (
429	(map { EV::io $_, EV::READ, sub { } }	945	(map { EV::io $_, EV::READ, sub { } }
430	keys %{ $dispatcher->{_descriptors} }),	946	keys %{ $dispatcher->{_descriptors} }),
		947
		948	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		949	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		950	0, sub { },
431	);	951	);
432
433	# if there are any timeouts, also create a timer
434	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
435	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
436	};	952	};
437		953
438	The callbacks are irrelevant, the only purpose of those watchers is	954	The callbacks are irrelevant (and are not even being called), the
439	to wake up the process as soon as one of those events occurs (socket	955	only purpose of those watchers is to wake up the process as soon as
440	readable, or timer timed out). The corresponding EV::check watcher will then	956	one of those events occurs (socket readable, or timer timed out). The
441	clean up:	957	corresponding EV::check watcher will then clean up:
442		958
443	our $snmp_check = EV::check sub {	959	our $snmp_check = EV::check sub {
444	# destroy all watchers	960	# destroy all watchers
445	@snmp_watcher = ();	961	@snmp_watcher = ();
446		962
447	# make the dispatcher handle any new stuff	963	# make the dispatcher handle any new stuff
		964	... not shown
448	};	965	};
449		966
450	The callbacks of the created watchers will not be called as the watchers	967	The callbacks of the created watchers will not be called as the watchers
451	are destroyed before this cna happen (remember EV::check gets called	968	are destroyed before this can happen (remember EV::check gets called
452	first).	969	first).
453		970
454	The C<check_ns> variant doesn't start (activate) the newly created watcher.	971	The C<check_ns> variant doesn't start (activate) the newly created watcher.
455		972
456	=back	973	=back
457		974
		975
		976	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		977
		978	Fork watchers are called when a C<fork ()> was detected. The invocation
		979	is done before the event loop blocks next and before C<check> watchers
		980	are being called, and only in the child after the fork.
		981
		982	=over 4
		983
		984	=item $w = EV::fork $callback
		985
		986	=item $w = EV::fork_ns $callback
		987
		988	=item $w = $loop->fork ($callback)
		989
		990	=item $w = $loop->fork_ns ($callback)
		991
		992	Call the callback before the event loop is resumed in the child process
		993	after a fork.
		994
		995	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		996
		997	=back
		998
		999
		1000	=head3 EMBED WATCHERS - when one backend isn't enough...
		1001
		1002	This is a rather advanced watcher type that lets you embed one event loop
		1003	into another (currently only IO events are supported in the embedded
		1004	loop, other types of watchers might be handled in a delayed or incorrect
		1005	fashion and must not be used).
		1006
		1007	See the libev documentation at
		1008	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1009	(locally installed as F<EV::libev>) for more details.
		1010
		1011	In short, this watcher is most useful on BSD systems without working
		1012	kqueue to still be able to handle a large number of sockets:
		1013
		1014	my $socket_loop;
		1015
		1016	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1017	if (
		1018	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1019	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1020	) {
		1021	# use kqueue for sockets
		1022	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1023	}
		1024
		1025	# use the default loop otherwise
		1026	$socket_loop \|\|= EV::default_loop;
		1027
		1028	=over 4
		1029
		1030	=item $w = EV::embed $otherloop[, $callback]
		1031
		1032	=item $w = EV::embed_ns $otherloop[, $callback]
		1033
		1034	=item $w = $loop->embed ($otherloop[, $callback])
		1035
		1036	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1037
		1038	Call the callback when the embedded event loop (C<$otherloop>) has any
		1039	I/O activity. The C<$callback> is optional: if it is missing, then the
		1040	embedded event loop will be managed automatically (which is recommended),
		1041	otherwise you have to invoke C<sweep> yourself.
		1042
		1043	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1044
		1045	=back
		1046
		1047	=head3 ASYNC WATCHERS - how to wake up another event loop
		1048
		1049	Async watchers are provided by EV, but have little use in perl directly,
		1050	as perl neither supports threads running in parallel nor direct access to
		1051	signal handlers or other contexts where they could be of value.
		1052
		1053	It is, however, possible to use them from the XS level.
		1054
		1055	Please see the libev documentation for further details.
		1056
		1057	=over 4
		1058
		1059	=item $w = EV::async $callback
		1060
		1061	=item $w = EV::async_ns $callback
		1062
		1063	=item $w->send
		1064
		1065	=item $bool = $w->async_pending
		1066
		1067	=back
		1068
		1069
		1070	=head1 PERL SIGNALS
		1071
		1072	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1073	with EV is as the same as any other C library: Perl-signals will only be
		1074	handled when Perl runs, which means your signal handler might be invoked
		1075	only the next time an event callback is invoked.
		1076
		1077	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1078	ensure proper operations with regards to other event watchers.
		1079
		1080	If you cannot do this for whatever reason, you can also force a watcher
		1081	to be called on every event loop iteration by installing a C<EV::check>
		1082	watcher:
		1083
		1084	my $async_check = EV::check sub { };
		1085
		1086	This ensures that perl gets into control for a short time to handle any
		1087	pending signals, and also ensures (slightly) slower overall operation.
		1088
458	=head1 THREADS	1089	=head1 ITHREADS
459		1090
460	Threads are not supported by this in any way. Perl pseudo-threads is evil	1091	Ithreads are not supported by this module in any way. Perl pseudo-threads
461	stuff and must die.	1092	is evil stuff and must die. Real threads as provided by Coro are fully
		1093	supported (and enhanced support is available via L<Coro::EV>).
		1094
		1095	=head1 FORK
		1096
		1097	Most of the "improved" event delivering mechanisms of modern operating
		1098	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1099	not supported and usually destructive). Libev makes it possible to work
		1100	around this by having a function that recreates the kernel state after
		1101	fork in the child.
		1102
		1103	On non-win32 platforms, this module requires the pthread_atfork
		1104	functionality to do this automatically for you. This function is quite
		1105	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1106	negligible, because everything the function currently does is set a flag
		1107	that is checked only when the event loop gets used the next time, so when
		1108	you do fork but not use EV, the overhead is minimal.
		1109
		1110	On win32, there is no notion of fork so all this doesn't apply, of course.
462		1111
463	=cut	1112	=cut
464		1113
465	our $DIED = sub {	1114	our $DIED = sub {
466	warn "EV: error in callback (ignoring): $@";	1115	warn "EV: error in callback (ignoring): $@";
467	};	1116	};
468		1117
469	init;	1118	default_loop
470		1119	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
471	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
472		1120
473	1;	1121	1;
474		1122
475	=head1 SEE ALSO	1123	=head1 SEE ALSO
476		1124
477	L<EV::DNS>, L<EV::AnyEvent>.	1125	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1126	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1127	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1128	event-loop agnostic and portable event driven programming.
478		1129
479	=head1 AUTHOR	1130	=head1 AUTHOR
480		1131
481	Marc Lehmann <schmorp@schmorp.de>	1132	Marc Lehmann <schmorp@schmorp.de>
482	http://home.schmorp.de/	1133	http://home.schmorp.de/
483		1134
484	=cut	1135	=cut
485		1136

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Comparing EV/EV.pm (file contents): Revision 1.25 by root, Fri Nov 2 22:18:49 2007 UTC vs. Revision 1.116 by root, Sat Jun 13 15:11:54 2009 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.25 by root, Fri Nov 2 22:18:49 2007 UTC vs.
Revision 1.116 by root, Sat Jun 13 15:11:54 2009 UTC