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

Comparing EV/EV.pm (file contents):
Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs.
Revision 1.113 by root, Sat Mar 14 16:24:27 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 = '0.1';	85	our $VERSION = '3.53';
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 $backend = EV::backend
102		208
		209	=item $backend = $loop->backend
		210
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	211	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
104	or EV::METHOD_EPOLL).	212	or EV::BACKEND_EPOLL).
105		213
106	=item EV::loop [$flags]	214	=item EV::loop [$flags]
107		215
		216	=item $loop->loop ([$flags])
		217
108	Begin checking for events and calling callbacks. It returns when a	218	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	219	callback calls EV::unloop.
110		220
111	The $flags argument can be one of the following:	221	The $flags argument can be one of the following:
112		222
113	0 as above	223	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	224	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	225	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		226
117	=item EV::loop_done [$how]	227	=item EV::unloop [$how]
118		228
		229	=item $loop->unloop ([$how])
		230
119	When called with no arguments or an argument of 1, makes the innermost	231	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	232	innermost call to EV::loop return.
121		233
122	When called with an agrument of 2, all calls to EV::loop will return as	234	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	235	fast as possible.
124		236
125	=back	237	=item $count = EV::loop_count
126		238
127	=head2 WATCHER	239	=item $count = $loop->loop_count
		240
		241	Return the number of times the event loop has polled for new
		242	events. Sometimes useful as a generation counter.
		243
		244	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		245
		246	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		247
		248	This function rolls together an I/O and a timer watcher for a single
		249	one-shot event without the need for managing a watcher object.
		250
		251	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		252	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		253	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		254	you do not want to wait for some I/O event, specify C<undef> for
		255	C<$fh_or_undef> and C<0> for C<$events>).
		256
		257	If timeout is C<undef> or negative, then there will be no
		258	timeout. Otherwise a EV::timer with this value will be started.
		259
		260	When an error occurs or either the timeout or I/O watcher triggers, then
		261	the callback will be called with the received event set (in general
		262	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		263	C<EV::WRITE> and C<EV::TIMEOUT>).
		264
		265	EV::once doesn't return anything: the watchers stay active till either
		266	of them triggers, then they will be stopped and freed, and the callback
		267	invoked.
		268
		269	=item EV::feed_fd_event ($fd, $revents)
		270
		271	=item $loop->feed_fd_event ($fd, $revents)
		272
		273	Feed an event on a file descriptor into EV. EV will react to this call as
		274	if the readyness notifications specified by C<$revents> (a combination of
		275	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		276
		277	=item EV::feed_signal_event ($signal)
		278
		279	Feed a signal event into EV. EV will react to this call as if the signal
		280	specified by C<$signal> had occured.
		281
		282	=item EV::set_io_collect_interval $time
		283
		284	=item $loop->set_io_collect_interval ($time)
		285
		286	=item EV::set_timeout_collect_interval $time
		287
		288	=item $loop->set_timeout_collect_interval ($time)
		289
		290	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		291	wait interval for timer events. See the libev documentation at
		292	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		293	(locally installed as F<EV::libev>) for a more detailed discussion.
		294
		295	=back
		296
		297
		298	=head1 WATCHER OBJECTS
128		299
129	A watcher is an object that gets created to record your interest in some	300	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	301	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	302	would create an EV::io watcher for that:
132		303
133	my $watcher = EV::io *STDIN, EV::READ, sub {	304	my $watcher = EV::io *STDIN, EV::READ, sub {
134	my ($watcher, $revents) = @_;	305	my ($watcher, $revents) = @_;
135	warn "yeah, STDIN should not be readable without blocking!\n"	306	warn "yeah, STDIN should now be readable without blocking!\n"
136	};	307	};
137		308
138	All watchers can be active (waiting for events) or inactive (paused). Only	309	All watchers can be active (waiting for events) or inactive (paused). Only
139	active watchers will have their callbacks invoked. All callbacks will be	310	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	311	called with at least two arguments: the watcher and a bitmask of received
141	events.	312	events.
142		313
143	Each watcher type has its associated bit in revents, so you can use the	314	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	315	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,	316	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	317	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	318	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	319	uses EV::TIMEOUT).
149		320
150	In the rare case where one wants to create a watcher but not start it at	321	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	322	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
157		328
158	Also, all methods changing some aspect of a watcher (->set, ->priority,	329	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,	330	->fh and so on) automatically stop and start it again if it is active,
160	which means pending events get lost.	331	which means pending events get lost.
161		332
162	=head2 WATCHER TYPES	333	=head2 COMMON WATCHER METHODS
163		334
164	Now lets move to the existing watcher types and asociated methods.	335	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		336
171	=over 4	337	=over 4
172		338
173	=item $w->start	339	=item $w->start
174		340
…		…
178		344
179	=item $w->stop	345	=item $w->stop
180		346
181	Stop a watcher if it is active. Also clear any pending events (events that	347	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),	348	have been received but that didn't yet result in a callback invocation),
183	regardless of wether the watcher was active or not.	349	regardless of whether the watcher was active or not.
184		350
185	=item $bool = $w->is_active	351	=item $bool = $w->is_active
186		352
187	Returns true if the watcher is active, false otherwise.	353	Returns true if the watcher is active, false otherwise.
		354
		355	=item $current_data = $w->data
		356
		357	=item $old_data = $w->data ($new_data)
		358
		359	Queries a freely usable data scalar on the watcher and optionally changes
		360	it. This is a way to associate custom data with a watcher:
		361
		362	my $w = EV::timer 60, 0, sub {
		363	warn $_[0]->data;
		364	};
		365	$w->data ("print me!");
188		366
189	=item $current_cb = $w->cb	367	=item $current_cb = $w->cb
190		368
191	=item $old_cb = $w->cb ($new_cb)	369	=item $old_cb = $w->cb ($new_cb)
192		370
…		…
201	watchers with higher priority will be invoked first. The valid range of	379	watchers with higher priority will be invoked first. The valid range of
202	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	380	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
203	-2). If the priority is outside this range it will automatically be	381	-2). If the priority is outside this range it will automatically be
204	normalised to the nearest valid priority.	382	normalised to the nearest valid priority.
205		383
206	The default priority of any newly-created weatcher is 0.	384	The default priority of any newly-created watcher is 0.
207		385
		386	Note that the priority semantics have not yet been fleshed out and are
		387	subject to almost certain change.
		388
208	=item $w->trigger ($revents)	389	=item $w->invoke ($revents)
209		390
210	Call the callback now with the given event mask.	391	Call the callback now with the given event mask.
211		392
		393	=item $w->feed_event ($revents)
		394
		395	Feed some events on this watcher into EV. EV will react to this call as if
		396	the watcher had received the given C<$revents> mask.
		397
		398	=item $revents = $w->clear_pending
		399
		400	If the watcher is pending, this function clears its pending status and
		401	returns its C<$revents> bitset (as if its callback was invoked). If the
		402	watcher isn't pending it does nothing and returns C<0>.
		403
		404	=item $previous_state = $w->keepalive ($bool)
		405
		406	Normally, C<EV::loop> will return when there are no active watchers
		407	(which is a "deadlock" because no progress can be made anymore). This is
		408	convinient because it allows you to start your watchers (and your jobs),
		409	call C<EV::loop> once and when it returns you know that all your jobs are
		410	finished (or they forgot to register some watchers for their task :).
		411
		412	Sometimes, however, this gets in your way, for example when the module
		413	that calls C<EV::loop> (usually the main program) is not the same module
		414	as a long-living watcher (for example a DNS client module written by
		415	somebody else even). Then you might want any outstanding requests to be
		416	handled, but you would not want to keep C<EV::loop> from returning just
		417	because you happen to have this long-running UDP port watcher.
		418
		419	In this case you can clear the keepalive status, which means that even
		420	though your watcher is active, it won't keep C<EV::loop> from returning.
		421
		422	The initial value for keepalive is true (enabled), and you can change it
		423	any time.
		424
		425	Example: Register an I/O watcher for some UDP socket but do not keep the
		426	event loop from running just because of that watcher.
		427
		428	my $udp_socket = ...
		429	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		430	$udp_watcher->keepalive (0);
		431
		432	=item $loop = $w->loop
		433
		434	Return the loop that this watcher is attached to.
		435
		436	=back
		437
		438
		439	=head1 WATCHER TYPES
		440
		441	Each of the following subsections describes a single watcher type.
		442
		443	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		444
		445	=over 4
212		446
213	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	447	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
214		448
215	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	449	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
216		450
		451	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		452
		453	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		454
217	As long as the returned watcher object is alive, call the C<$callback>	455	As long as the returned watcher object is alive, call the C<$callback>
218	when the events specified in C<$eventmask>.	456	when at least one of events specified in C<$eventmask> occurs.
219		457
220	The $eventmask can be one or more of these constants ORed together:	458	The $eventmask can be one or more of these constants ORed together:
221		459
222	EV::READ wait until read() wouldn't block anymore	460	EV::READ wait until read() wouldn't block anymore
223	EV::WRITE wait until write() wouldn't block anymore	461	EV::WRITE wait until write() wouldn't block anymore
…		…
239		477
240	=item $old_eventmask = $w->events ($new_eventmask)	478	=item $old_eventmask = $w->events ($new_eventmask)
241		479
242	Returns the previously set event mask and optionally set a new one.	480	Returns the previously set event mask and optionally set a new one.
243		481
		482	=back
		483
		484
		485	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		486
		487	=over 4
244		488
245	=item $w = EV::timer $after, $repeat, $callback	489	=item $w = EV::timer $after, $repeat, $callback
246		490
247	=item $w = EV::timer_ns $after, $repeat, $callback	491	=item $w = EV::timer_ns $after, $repeat, $callback
248		492
249	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	493	=item $w = $loop->timer ($after, $repeat, $callback)
250	the timer will be restarted (with the $repeat value as $after) after the	494
251	callback returns.	495	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		496
		497	Calls the callback after C<$after> seconds (which may be fractional). If
		498	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		499	value as $after) after the callback returns.
252		500
253	This means that the callback would be called roughly after C<$after>	501	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	502	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	503	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.	504	loop iteration, and might drift in other cases. If that isn't acceptable,
		505	look at EV::periodic, which can provide long-term stable timers.
257		506
258	The timer is based on a monotonic clock, that is if somebody is sitting	507	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	508	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.	509	clock, the timer will nevertheless run (roughly) the same time.
261		510
262	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	511	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
263		512
264	=item $w->set ($after, $repeat)	513	=item $w->set ($after, $repeat)
265		514
266	Reconfigures the watcher, see the constructor above for details. Can be at	515	Reconfigures the watcher, see the constructor above for details. Can be called at
267	any time.	516	any time.
268		517
269	=item $w->again	518	=item $w->again
270		519
271	Similar to the C<start> method, but has special semantics for repeating timers:	520	Similar to the C<start> method, but has special semantics for repeating timers:
		521
		522	If the timer is active and non-repeating, it will be stopped.
272		523
273	If the timer is active and repeating, reset the timeout to occur	524	If the timer is active and repeating, reset the timeout to occur
274	C<$repeat> seconds after now.	525	C<$repeat> seconds after now.
275		526
276	If the timer is active and non-repeating, it will be stopped.
277
278	If the timer is in active and repeating, start it.	527	If the timer is inactive and repeating, start it using the repeat value.
279		528
280	Otherwise do nothing.	529	Otherwise do nothing.
281		530
282	This behaviour is useful when you have a timeout for some IO	531	This behaviour is useful when you have a timeout for some IO
283	operation. You create a timer object with the same value for C<$after> and	532	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	533	C<$repeat>, and then, in the read/write watcher, run the C<again> method
285	on the timeout.	534	on the timeout.
286		535
		536	=back
287		537
		538
		539	=head3 PERIODIC WATCHERS - to cron or not to cron?
		540
		541	=over 4
		542
288	=item $w = EV::periodic $at, $interval, $callback	543	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
289		544
290	=item $w = EV::periodic_ns $at, $interval, $callback	545	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
291		546
292	Similar to EV::timer, but the time is given as an absolute point in time	547	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
293	(C<$at>), plus an optional C<$interval>.
294		548
295	If the C<$interval> is zero, then the callback will be called at the time	549	=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		550
299	If the C<$interval> is nonzero, then the watcher will always be scheduled	551	Similar to EV::timer, but is not based on relative timeouts but on
300	to time out at the next C<$at + N * $interval> time.	552	absolute times. Apart from creating "simple" timers that trigger "at" the
		553	specified time, it can also be used for non-drifting absolute timers and
		554	more complex, cron-like, setups that are not adversely affected by time
		555	jumps (i.e. when the system clock is changed by explicit date -s or other
		556	means such as ntpd). It is also the most complex watcher type in EV.
301		557
302	This can be used to schedule a callback to run at very regular intervals,	558	It has three distinct "modes":
303	as long as the processing time is less then the interval (otherwise	559
304	obviously events will be skipped).	560	=over 4
		561
		562	=item * absolute timer ($interval = $reschedule_cb = 0)
		563
		564	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		565	will not adjust when a time jump occurs, that is, if it is to be run
		566	at January 1st 2011 then it will run when the system time reaches or
		567	surpasses this time.
		568
		569	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
		570
		571	In this mode the watcher will always be scheduled to time out at the
		572	next C<$at + N * $interval> time (for some integer N) and then repeat,
		573	regardless of any time jumps.
		574
		575	This can be used to create timers that do not drift with respect to system
		576	time:
		577
		578	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		579
		580	That doesn't mean there will always be 3600 seconds in between triggers,
		581	but only that the the clalback will be called when the system time shows a
		582	full hour (UTC).
305		583
306	Another way to think about it (for the mathematically inclined) is that	584	Another way to think about it (for the mathematically inclined) is that
307	EV::periodic will try to run the callback at the next possible time where	585	EV::periodic will try to run the callback in this mode at the next
308	C<$time = $at (mod $interval)>, regardless of any time jumps.	586	possible time where C<$time = $at (mod $interval)>, regardless of any time
		587	jumps.
309		588
310	This periodic timer is based on "wallclock time", that is, if the clock	589	=item * manual reschedule mode ($reschedule_cb = coderef)
311	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	590
312	the specified time. This means it will never drift (it might jitter, but	591	In this mode $interval and $at are both being ignored. Instead, each
313	it will not drift).	592	time the periodic watcher gets scheduled, the reschedule callback
		593	($reschedule_cb) will be called with the watcher as first, and the current
		594	time as second argument.
		595
		596	I<This callback MUST NOT stop or destroy this or any other periodic
		597	watcher, ever, and MUST NOT call any event loop functions or methods>. If
		598	you need to stop it, return 1e30 and stop it afterwards. You may create
		599	and start a C<EV::prepare> watcher for this task.
		600
		601	It must return the next time to trigger, based on the passed time value
		602	(that is, the lowest time value larger than or equal to to the second
		603	argument). It will usually be called just before the callback will be
		604	triggered, but might be called at other times, too.
		605
		606	This can be used to create very complex timers, such as a timer that
		607	triggers on each midnight, local time (actually 24 hours after the last
		608	midnight, to keep the example simple. If you know a way to do it correctly
		609	in about the same space (without requiring elaborate modules), drop me a
		610	note :):
		611
		612	my $daily = EV::periodic 0, 0, sub {
		613	my ($w, $now) = @_;
		614
		615	use Time::Local ();
		616	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		617	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		618	}, sub {
		619	print "it's midnight or likely shortly after, now\n";
		620	};
		621
		622	=back
314		623
315	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	624	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
316		625
317	=item $w->set ($at, $interval)	626	=item $w->set ($at, $interval, $reschedule_cb)
318		627
319	Reconfigures the watcher, see the constructor above for details. Can be at	628	Reconfigures the watcher, see the constructor above for details. Can be called at
320	any time.	629	any time.
321		630
		631	=item $w->again
		632
		633	Simply stops and starts the watcher again.
		634
		635	=item $time = $w->at
		636
		637	Return the time that the watcher is expected to trigger next.
		638
		639	=back
		640
		641
		642	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		643
		644	=over 4
322		645
323	=item $w = EV::signal $signal, $callback	646	=item $w = EV::signal $signal, $callback
324		647
325	=item $w = EV::signal_ns $signal, $callback	648	=item $w = EV::signal_ns $signal, $callback
326		649
327	Call the callback when $signal is received (the signal can be specified	650	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).	651	number or by name, just as with C<kill> or C<%SIG>).
329		652
330	EV will grab the signal for the process (the kernel only allows one	653	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,	654	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	655	and removes it again when you stop it. Perl does the same when you
333	add/remove callbacks to %SIG, so watch out.	656	add/remove callbacks to C<%SIG>, so watch out.
334		657
335	You can have as many signal watchers per signal as you want.	658	You can have as many signal watchers per signal as you want.
336		659
337	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	660	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
338		661
339	=item $w->set ($signal)	662	=item $w->set ($signal)
340		663
341	Reconfigures the watcher, see the constructor above for details. Can be at	664	Reconfigures the watcher, see the constructor above for details. Can be
342	any time.	665	called at any time.
343		666
344	=item $current_signum = $w->signal	667	=item $current_signum = $w->signal
345		668
346	=item $old_signum = $w->signal ($new_signal)	669	=item $old_signum = $w->signal ($new_signal)
347		670
348	Returns the previously set signal (always as a number not name) and	671	Returns the previously set signal (always as a number not name) and
349	optionally set a new one.	672	optionally set a new one.
350		673
		674	=back
351		675
		676
		677	=head3 CHILD WATCHERS - watch out for process status changes
		678
		679	=over 4
		680
352	=item $w = EV::child $pid, $callback	681	=item $w = EV::child $pid, $trace, $callback
353		682
354	=item $w = EV::child_ns $pid, $callback	683	=item $w = EV::child_ns $pid, $trace, $callback
		684
		685	=item $w = $loop->child ($pid, $trace, $callback)
		686
		687	=item $w = $loop->child_ns ($pid, $trace, $callback)
355		688
356	Call the callback when a status change for pid C<$pid> (or any pid	689	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	690	if C<$pid> is 0) has been received (a status change happens when the
		691	process terminates or is killed, or, when trace is true, additionally when
		692	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	693	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
359	changed/zombie children and call the callback.	694	changed/zombie children and call the callback.
360		695
361	Unlike all other callbacks, this callback will be called with an	696	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>	697	has exited but before the event loop has started its next iteration (for
363	function for details.	698	example, first you C<fork>, then the new child process might exit, and
		699	only then do you install a child watcher in the parent for the new pid).
364		700
		701	You can access both exit (or tracing) status and pid by using the
		702	C<rstatus> and C<rpid> methods on the watcher object.
		703
365	You can have as many pid watchers per pid as you want.	704	You can have as many pid watchers per pid as you want, they will all be
		705	called.
366		706
367	The C<child_ns> variant doesn't start (activate) the newly created watcher.	707	The C<child_ns> variant doesn't start (activate) the newly created watcher.
368		708
369	=item $w->set ($pid)	709	=item $w->set ($pid, $trace)
370		710
371	Reconfigures the watcher, see the constructor above for details. Can be at	711	Reconfigures the watcher, see the constructor above for details. Can be called at
372	any time.	712	any time.
373		713
374	=item $current_pid = $w->pid	714	=item $current_pid = $w->pid
375		715
376	=item $old_pid = $w->pid ($new_pid)
377
378	Returns the previously set process id and optionally set a new one.	716	Returns the previously set process id and optionally set a new one.
379		717
		718	=item $exit_status = $w->rstatus
		719
		720	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		721	in perlfunc).
		722
		723	=item $pid = $w->rpid
		724
		725	Return the pid of the awaited child (useful when you have installed a
		726	watcher for all pids).
		727
		728	=back
		729
		730
		731	=head3 STAT WATCHERS - did the file attributes just change?
		732
		733	=over 4
		734
		735	=item $w = EV::stat $path, $interval, $callback
		736
		737	=item $w = EV::stat_ns $path, $interval, $callback
		738
		739	=item $w = $loop->stat ($path, $interval, $callback)
		740
		741	=item $w = $loop->stat_ns ($path, $interval, $callback)
		742
		743	Call the callback when a file status change has been detected on
		744	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		745	to "path does not exist" is a status change like any other.
		746
		747	The C<$interval> is a recommended polling interval for systems where
		748	OS-supported change notifications don't exist or are not supported. If
		749	you use C<0> then an unspecified default is used (which is highly
		750	recommended!), which is to be expected to be around five seconds usually.
		751
		752	This watcher type is not meant for massive numbers of stat watchers,
		753	as even with OS-supported change notifications, this can be
		754	resource-intensive.
		755
		756	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		757
		758	=item ... = $w->stat
		759
		760	This call is very similar to the perl C<stat> built-in: It stats (using
		761	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		762	well as EV's idea of the current stat values) to the values found.
		763
		764	In scalar context, a boolean is return indicating success or failure of
		765	the stat. In list context, the same 13-value list as with stat is returned
		766	(except that the blksize and blocks fields are not reliable).
		767
		768	In the case of an error, errno is set to C<ENOENT> (regardless of the
		769	actual error value) and the C<nlink> value is forced to zero (if the stat
		770	was successful then nlink is guaranteed to be non-zero).
		771
		772	See also the next two entries for more info.
		773
		774	=item ... = $w->attr
		775
		776	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		777	the values most recently detected by EV. See the next entry for more info.
		778
		779	=item ... = $w->prev
		780
		781	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		782	the previous set of values, before the change.
		783
		784	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		785	to the values found I<before> a change was detected, while C<< $w->attr >>
		786	returns the values found leading to the change detection. The difference (if any)
		787	between C<prev> and C<attr> is what triggered the callback.
		788
		789	If you did something to the filesystem object and do not want to trigger
		790	yet another change, you can call C<stat> to update EV's idea of what the
		791	current attributes are.
		792
		793	=item $w->set ($path, $interval)
		794
		795	Reconfigures the watcher, see the constructor above for details. Can be
		796	called at any time.
		797
		798	=item $current_path = $w->path
		799
		800	=item $old_path = $w->path ($new_path)
		801
		802	Returns the previously set path and optionally set a new one.
		803
		804	=item $current_interval = $w->interval
		805
		806	=item $old_interval = $w->interval ($new_interval)
		807
		808	Returns the previously set interval and optionally set a new one. Can be
		809	used to query the actual interval used.
		810
		811	=back
		812
		813
		814	=head3 IDLE WATCHERS - when you've got nothing better to do...
		815
		816	=over 4
380		817
381	=item $w = EV::idle $callback	818	=item $w = EV::idle $callback
382		819
383	=item $w = EV::idle_ns $callback	820	=item $w = EV::idle_ns $callback
384		821
385	Call the callback when there are no pending io, timer/periodic, signal or	822	=item $w = $loop->idle ($callback)
386	child events, i.e. when the process is idle.	823
		824	=item $w = $loop->idle_ns ($callback)
		825
		826	Call the callback when there are no other pending watchers of the same or
		827	higher priority (excluding check, prepare and other idle watchers of the
		828	same or lower priority, of course). They are called idle watchers because
		829	when the watcher is the highest priority pending event in the process, the
		830	process is considered to be idle at that priority.
		831
		832	If you want a watcher that is only ever called when I<no> other events are
		833	outstanding you have to set the priority to C<EV::MINPRI>.
387		834
388	The process will not block as long as any idle watchers are active, and	835	The process will not block as long as any idle watchers are active, and
389	they will be called repeatedly until stopped.	836	they will be called repeatedly until stopped.
390		837
		838	For example, if you have idle watchers at priority C<0> and C<1>, and
		839	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		840	and the I/O watcher will always run when ready. Only when the idle watcher
		841	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		842	pending with the C<0>-priority idle watcher be invoked.
		843
391	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	844	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
392		845
		846	=back
		847
		848
		849	=head3 PREPARE WATCHERS - customise your event loop!
		850
		851	=over 4
393		852
394	=item $w = EV::prepare $callback	853	=item $w = EV::prepare $callback
395		854
396	=item $w = EV::prepare_ns $callback	855	=item $w = EV::prepare_ns $callback
		856
		857	=item $w = $loop->prepare ($callback)
		858
		859	=item $w = $loop->prepare_ns ($callback)
397		860
398	Call the callback just before the process would block. You can still	861	Call the callback just before the process would block. You can still
399	create/modify any watchers at this point.	862	create/modify any watchers at this point.
400		863
401	See the EV::check watcher, below, for explanations and an example.	864	See the EV::check watcher, below, for explanations and an example.
402		865
403	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	866	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
404		867
		868	=back
		869
		870
		871	=head3 CHECK WATCHERS - customise your event loop even more!
		872
		873	=over 4
405		874
406	=item $w = EV::check $callback	875	=item $w = EV::check $callback
407		876
408	=item $w = EV::check_ns $callback	877	=item $w = EV::check_ns $callback
		878
		879	=item $w = $loop->check ($callback)
		880
		881	=item $w = $loop->check_ns ($callback)
409		882
410	Call the callback just after the process wakes up again (after it has	883	Call the callback just after the process wakes up again (after it has
411	gathered events), but before any other callbacks have been invoked.	884	gathered events), but before any other callbacks have been invoked.
412		885
413	This is used to integrate other event-based software into the EV	886	This is used to integrate other event-based software into the EV
…		…
421	# do nothing unless active	894	# do nothing unless active
422	$dispatcher->{_event_queue_h}	895	$dispatcher->{_event_queue_h}
423	or return;	896	or return;
424		897
425	# make the dispatcher handle any outstanding stuff	898	# make the dispatcher handle any outstanding stuff
		899	... not shown
426		900
427	# create an IO watcher for each and every socket	901	# create an I/O watcher for each and every socket
428	@snmp_watcher = (	902	@snmp_watcher = (
429	(map { EV::io $_, EV::READ, sub { } }	903	(map { EV::io $_, EV::READ, sub { } }
430	keys %{ $dispatcher->{_descriptors} }),	904	keys %{ $dispatcher->{_descriptors} }),
		905
		906	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		907	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		908	0, sub { },
431	);	909	);
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	};	910	};
437		911
438	The callbacks are irrelevant, the only purpose of those watchers is	912	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	913	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	914	one of those events occurs (socket readable, or timer timed out). The
441	clean up:	915	corresponding EV::check watcher will then clean up:
442		916
443	our $snmp_check = EV::check sub {	917	our $snmp_check = EV::check sub {
444	# destroy all watchers	918	# destroy all watchers
445	@snmp_watcher = ();	919	@snmp_watcher = ();
446		920
447	# make the dispatcher handle any new stuff	921	# make the dispatcher handle any new stuff
		922	... not shown
448	};	923	};
449		924
450	The callbacks of the created watchers will not be called as the watchers	925	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	926	are destroyed before this can happen (remember EV::check gets called
452	first).	927	first).
453		928
454	The C<check_ns> variant doesn't start (activate) the newly created watcher.	929	The C<check_ns> variant doesn't start (activate) the newly created watcher.
455		930
456	=back	931	=back
457		932
		933
		934	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		935
		936	Fork watchers are called when a C<fork ()> was detected. The invocation
		937	is done before the event loop blocks next and before C<check> watchers
		938	are being called, and only in the child after the fork.
		939
		940	=over 4
		941
		942	=item $w = EV::fork $callback
		943
		944	=item $w = EV::fork_ns $callback
		945
		946	=item $w = $loop->fork ($callback)
		947
		948	=item $w = $loop->fork_ns ($callback)
		949
		950	Call the callback before the event loop is resumed in the child process
		951	after a fork.
		952
		953	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		954
		955	=back
		956
		957
		958	=head3 EMBED WATCHERS - when one backend isn't enough...
		959
		960	This is a rather advanced watcher type that lets you embed one event loop
		961	into another (currently only IO events are supported in the embedded
		962	loop, other types of watchers might be handled in a delayed or incorrect
		963	fashion and must not be used).
		964
		965	See the libev documentation at
		966	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		967	(locally installed as F<EV::libev>) for more details.
		968
		969	In short, this watcher is most useful on BSD systems without working
		970	kqueue to still be able to handle a large number of sockets:
		971
		972	my $socket_loop;
		973
		974	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		975	if (
		976	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		977	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		978	) {
		979	# use kqueue for sockets
		980	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		981	}
		982
		983	# use the default loop otherwise
		984	$socket_loop \|\|= EV::default_loop;
		985
		986	=over 4
		987
		988	=item $w = EV::embed $otherloop[, $callback]
		989
		990	=item $w = EV::embed_ns $otherloop[, $callback]
		991
		992	=item $w = $loop->embed ($otherloop[, $callback])
		993
		994	=item $w = $loop->embed_ns ($otherloop[, $callback])
		995
		996	Call the callback when the embedded event loop (C<$otherloop>) has any
		997	I/O activity. The C<$callback> is optional: if it is missing, then the
		998	embedded event loop will be managed automatically (which is recommended),
		999	otherwise you have to invoke C<sweep> yourself.
		1000
		1001	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1002
		1003	=back
		1004
		1005	=head3 ASYNC WATCHERS - how to wake up another event loop
		1006
		1007	Async watchers are provided by EV, but have little use in perl directly, as perl
		1008	neither supports threads nor direct access to signal handlers or other
		1009	contexts where they could be of value.
		1010
		1011	It is, however, possible to use them from the XS level.
		1012
		1013	Please see the libev documentation for further details.
		1014
		1015	=over 4
		1016
		1017	=item $w = EV::async $callback
		1018
		1019	=item $w = EV::async_ns $callback
		1020
		1021	=item $w->send
		1022
		1023	=item $bool = $w->async_pending
		1024
		1025	=back
		1026
		1027
		1028	=head1 PERL SIGNALS
		1029
		1030	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1031	with EV is as the same as any other C library: Perl-signals will only be
		1032	handled when Perl runs, which means your signal handler might be invoked
		1033	only the next time an event callback is invoked.
		1034
		1035	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1036	ensure proper operations with regards to other event watchers.
		1037
		1038	If you cannot do this for whatever reason, you can also force a watcher
		1039	to be called on every event loop iteration by installing a C<EV::check>
		1040	watcher:
		1041
		1042	my $async_check = EV::check sub { };
		1043
		1044	This ensures that perl gets into control for a short time to handle any
		1045	pending signals, and also ensures (slightly) slower overall operation.
		1046
458	=head1 THREADS	1047	=head1 THREADS
459		1048
460	Threads are not supported by this in any way. Perl pseudo-threads is evil	1049	Threads are not supported by this module in any way. Perl pseudo-threads
461	stuff and must die.	1050	is evil stuff and must die. As soon as Perl gains real threads I will work
		1051	on thread support for it.
		1052
		1053	=head1 FORK
		1054
		1055	Most of the "improved" event delivering mechanisms of modern operating
		1056	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1057	not supported and usually destructive). Libev makes it possible to work
		1058	around this by having a function that recreates the kernel state after
		1059	fork in the child.
		1060
		1061	On non-win32 platforms, this module requires the pthread_atfork
		1062	functionality to do this automatically for you. This function is quite
		1063	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1064	negligible, because everything the function currently does is set a flag
		1065	that is checked only when the event loop gets used the next time, so when
		1066	you do fork but not use EV, the overhead is minimal.
		1067
		1068	On win32, there is no notion of fork so all this doesn't apply, of course.
462		1069
463	=cut	1070	=cut
464		1071
465	our $DIED = sub {	1072	our $DIED = sub {
466	warn "EV: error in callback (ignoring): $@";	1073	warn "EV: error in callback (ignoring): $@";
467	};	1074	};
468		1075
469	init;	1076	default_loop
470		1077	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
471	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
472		1078
473	1;	1079	1;
474		1080
475	=head1 SEE ALSO	1081	=head1 SEE ALSO
476		1082
477	L<EV::DNS>, L<EV::AnyEvent>.	1083	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1084	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1085	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1086	event-loop agnostic and portable event driven programming.
478		1087
479	=head1 AUTHOR	1088	=head1 AUTHOR
480		1089
481	Marc Lehmann <schmorp@schmorp.de>	1090	Marc Lehmann <schmorp@schmorp.de>
482	http://home.schmorp.de/	1091	http://home.schmorp.de/
483		1092
484	=cut	1093	=cut
485		1094

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Comparing EV/EV.pm (file contents): Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs. Revision 1.113 by root, Sat Mar 14 16:24:27 2009 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs.
Revision 1.113 by root, Sat Mar 14 16:24:27 2009 UTC