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

Comparing EV/EV.pm (file contents):
Revision 1.22 by root, Fri Nov 2 11:02:22 2007 UTC vs.
Revision 1.127 by root, Sun Mar 28 15:48:21 2010 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
		55
		56	=head1 BEFORE YOU START USING THIS MODULE
		57
		58	If you only need timer, I/O, signal, child and idle watchers and not the
		59	advanced functionality of this module, consider using L<AnyEvent> instead,
		60	specifically the simplified API described in L<AE>.
		61
		62	When used with EV as backend, the L<AE> API is as fast as the native L<EV>
		63	API, but your programs/modules will still run with many other event loops.
52		64
53	=head1 DESCRIPTION	65	=head1 DESCRIPTION
54		66
55	This module provides an interface to libev	67	This module provides an interface to libev
56	(L<http://software.schmorp.de/pkg/libev.html>).	68	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		69	below is comprehensive, one might also consult the documentation of
		70	libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
		71	F<perldoc EV::libev>) for more subtle details on watcher semantics or some
		72	discussion on the available backends, or how to force a specific backend
		73	with C<LIBEV_FLAGS>, or just about in any case because it has much more
		74	detailed information.
		75
		76	This module is very fast and scalable. It is actually so fast that you
		77	can use it through the L<AnyEvent> module, stay portable to other event
		78	loops (if you don't rely on any watcher types not available through it)
		79	and still be faster than with any other event loop currently supported in
		80	Perl.
		81
		82	=head2 MODULE EXPORTS
		83
		84	This module does not export any symbols.
57		85
58	=cut	86	=cut
59		87
60	package EV;	88	package EV;
61		89
62	use strict;	90	use common::sense;
63		91
64	BEGIN {	92	BEGIN {
65	our $VERSION = '0.1';	93	our $VERSION = '4.00';
66	use XSLoader;	94	use XSLoader;
67	XSLoader::load "EV", $VERSION;	95	XSLoader::load "EV", $VERSION;
68	}	96	}
69		97
70	@EV::Io::ISA =	98	@EV::IO::ISA =
71	@EV::Timer::ISA =	99	@EV::Timer::ISA =
72	@EV::Periodic::ISA =	100	@EV::Periodic::ISA =
73	@EV::Signal::ISA =	101	@EV::Signal::ISA =
		102	@EV::Child::ISA =
		103	@EV::Stat::ISA =
74	@EV::Idle::ISA =	104	@EV::Idle::ISA =
75	@EV::Prepare::ISA =	105	@EV::Prepare::ISA =
76	@EV::Check::ISA =	106	@EV::Check::ISA =
77	@EV::Child::ISA = "EV::Watcher";	107	@EV::Embed::ISA =
		108	@EV::Fork::ISA =
		109	@EV::Async::ISA =
		110	"EV::Watcher";
		111
		112	@EV::Loop::Default::ISA = "EV::Loop";
		113
		114	=head1 EVENT LOOPS
		115
		116	EV supports multiple event loops: There is a single "default event loop"
		117	that can handle everything including signals and child watchers, and any
		118	number of "dynamic event loops" that can use different backends (with
		119	various limitations), but no child and signal watchers.
		120
		121	You do not have to do anything to create the default event loop: When
		122	the module is loaded a suitable backend is selected on the premise of
		123	selecting a working backend (which for example rules out kqueue on most
		124	BSDs). Modules should, unless they have "special needs" always use the
		125	default loop as this is fastest (perl-wise), best supported by other
		126	modules (e.g. AnyEvent or Coro) and most portable event loop.
		127
		128	For specific programs you can create additional event loops dynamically.
		129
		130	If you want to take advantage of kqueue (which often works properly for
		131	sockets only) even though the default loop doesn't enable it, you can
		132	I<embed> a kqueue loop into the default loop: running the default loop
		133	will then also service the kqueue loop to some extent. See the example in
		134	the section about embed watchers for an example on how to achieve that.
		135
		136	=over 4
		137
		138	=item $loop = new EV::Loop [$flags]
		139
		140	Create a new event loop as per the specified flags. Please refer to
		141	the C<ev_loop_new ()> function description in the libev documentation
		142	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
		143	or locally-installed as F<EV::libev> manpage) for more info.
		144
		145	The loop will automatically be destroyed when it is no longer referenced
		146	by any watcher and the loop object goes out of scope.
		147
		148	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		149	is recommended, as only the default event loop is protected by this
		150	module. If you I<are> embedding this loop in the default loop, this is not
		151	necessary, as C<EV::embed> automatically does the right thing on fork.
		152
		153	=item $loop->loop_fork
		154
		155	Must be called after a fork in the child, before entering or continuing
		156	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		157	this function automatically, at some performance loss (refer to the libev
		158	documentation).
		159
		160	=item $loop->loop_verify
		161
		162	Calls C<ev_verify> to make internal consistency checks (for debugging
		163	libev) and abort the program if any data structures were found to be
		164	corrupted.
		165
		166	=item $loop = EV::default_loop [$flags]
		167
		168	Return the default loop (which is a singleton object). Since this module
		169	already creates the default loop with default flags, specifying flags here
		170	will not have any effect unless you destroy the default loop first, which
		171	isn't supported. So in short: don't do it, and if you break it, you get to
		172	keep the pieces.
		173
		174	=back
		175
78		176
79	=head1 BASIC INTERFACE	177	=head1 BASIC INTERFACE
80		178
81	=over 4	179	=over 4
82		180
83	=item $EV::DIED	181	=item $EV::DIED
84		182
85	Must contain a reference to a function that is called when a callback	183	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	184	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	185	informative message and continues.
88		186
89	If this callback throws an exception it will be silently ignored.	187	If this callback throws an exception it will be silently ignored.
90		188
		189	=item $flags = EV::supported_backends
		190
		191	=item $flags = EV::recommended_backends
		192
		193	=item $flags = EV::embeddable_backends
		194
		195	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		196	instance of EV, the set of recommended backends (supposed to be good) for
		197	this platform and the set of embeddable backends (see EMBED WATCHERS).
		198
		199	=item EV::sleep $seconds
		200
		201	Block the process for the given number of (fractional) seconds.
		202
91	=item $time = EV::time	203	=item $time = EV::time
92		204
93	Returns the current time in (fractional) seconds since the epoch.	205	Returns the current time in (fractional) seconds since the epoch.
94		206
95	=item $time = EV::now	207	=item $time = EV::now
96		208
		209	=item $time = $loop->now
		210
97	Returns the time the last event loop iteration has been started. This	211	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	212	is the time that (relative) timers are based on, and referring to it is
99	usually faster then calling EV::time.	213	usually faster then calling EV::time.
100		214
101	=item $method = EV::ev_method	215	=item EV::now_update
102		216
		217	=item $loop->now_update
		218
		219	Establishes the current time by querying the kernel, updating the time
		220	returned by C<EV::now> in the progress. This is a costly operation and
		221	is usually done automatically within C<EV::loop>.
		222
		223	This function is rarely useful, but when some event callback runs for a
		224	very long time without entering the event loop, updating libev's idea of
		225	the current time is a good idea.
		226
		227	=item EV::suspend
		228
		229	=item $loop->suspend
		230
		231	=item EV::resume
		232
		233	=item $loop->resume
		234
		235	These two functions suspend and resume a loop, for use when the loop is
		236	not used for a while and timeouts should not be processed.
		237
		238	A typical use case would be an interactive program such as a game: When
		239	the user presses C<^Z> to suspend the game and resumes it an hour later it
		240	would be best to handle timeouts as if no time had actually passed while
		241	the program was suspended. This can be achieved by calling C<suspend>
		242	in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
		243	C<resume> directly afterwards to resume timer processing.
		244
		245	Effectively, all C<timer> watchers will be delayed by the time spend
		246	between C<suspend> and C<resume>, and all C<periodic> watchers
		247	will be rescheduled (that is, they will lose any events that would have
		248	occured while suspended).
		249
		250	After calling C<suspend> you B<must not> call I<any> function on the given
		251	loop other than C<resume>, and you B<must not> call C<resume>
		252	without a previous call to C<suspend>.
		253
		254	Calling C<suspend>/C<resume> has the side effect of updating the event
		255	loop time (see C<now_update>).
		256
		257	=item $backend = EV::backend
		258
		259	=item $backend = $loop->backend
		260
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	261	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
104	or EV::METHOD_EPOLL).	262	or EV::BACKEND_EPOLL).
105		263
106	=item EV::loop [$flags]	264	=item EV::loop [$flags]
107		265
		266	=item $loop->loop ([$flags])
		267
108	Begin checking for events and calling callbacks. It returns when a	268	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	269	callback calls EV::unloop.
110		270
111	The $flags argument can be one of the following:	271	The $flags argument can be one of the following:
112		272
113	0 as above	273	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	274	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	275	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		276
117	=item EV::loop_done [$how]	277	=item EV::unloop [$how]
118		278
		279	=item $loop->unloop ([$how])
		280
119	When called with no arguments or an argument of 1, makes the innermost	281	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	282	innermost call to EV::loop return.
121		283
122	When called with an agrument of 2, all calls to EV::loop will return as	284	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	285	fast as possible.
124		286
125	=back	287	=item $count = EV::loop_count
126		288
127	=head2 WATCHER	289	=item $count = $loop->loop_count
		290
		291	Return the number of times the event loop has polled for new
		292	events. Sometimes useful as a generation counter.
		293
		294	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		295
		296	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		297
		298	This function rolls together an I/O and a timer watcher for a single
		299	one-shot event without the need for managing a watcher object.
		300
		301	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		302	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		303	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		304	you do not want to wait for some I/O event, specify C<undef> for
		305	C<$fh_or_undef> and C<0> for C<$events>).
		306
		307	If timeout is C<undef> or negative, then there will be no
		308	timeout. Otherwise a EV::timer with this value will be started.
		309
		310	When an error occurs or either the timeout or I/O watcher triggers, then
		311	the callback will be called with the received event set (in general
		312	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		313	C<EV::WRITE> and C<EV::TIMER>).
		314
		315	EV::once doesn't return anything: the watchers stay active till either
		316	of them triggers, then they will be stopped and freed, and the callback
		317	invoked.
		318
		319	=item EV::feed_fd_event ($fd, $revents)
		320
		321	=item $loop->feed_fd_event ($fd, $revents)
		322
		323	Feed an event on a file descriptor into EV. EV will react to this call as
		324	if the readyness notifications specified by C<$revents> (a combination of
		325	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		326
		327	=item EV::feed_signal_event ($signal)
		328
		329	Feed a signal event into EV. EV will react to this call as if the signal
		330	specified by C<$signal> had occured.
		331
		332	=item EV::set_io_collect_interval $time
		333
		334	=item $loop->set_io_collect_interval ($time)
		335
		336	=item EV::set_timeout_collect_interval $time
		337
		338	=item $loop->set_timeout_collect_interval ($time)
		339
		340	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		341	wait interval for timer events. See the libev documentation at
		342	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		343	(locally installed as F<EV::libev>) for a more detailed discussion.
		344
		345	=item $count = EV::pending_count
		346
		347	=item $count = $loop->pending_count
		348
		349	Returns the number of currently pending watchers.
		350
		351	=item EV::invoke_pending
		352
		353	=item $loop->invoke_pending
		354
		355	Invoke all currently pending watchers.
		356
		357	=back
		358
		359
		360	=head1 WATCHER OBJECTS
128		361
129	A watcher is an object that gets created to record your interest in some	362	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	363	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	364	would create an EV::io watcher for that:
132		365
133	my $watcher = EV::io *STDIN, EV::READ, sub {	366	my $watcher = EV::io *STDIN, EV::READ, sub {
134	my ($watcher, $revents) = @_;	367	my ($watcher, $revents) = @_;
135	warn "yeah, STDIN should not be readable without blocking!\n"	368	warn "yeah, STDIN should now be readable without blocking!\n"
136	};	369	};
137		370
138	All watchers can be active (waiting for events) or inactive (paused). Only	371	All watchers can be active (waiting for events) or inactive (paused). Only
139	active watchers will have their callbacks invoked. All callbacks will be	372	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	373	called with at least two arguments: the watcher and a bitmask of received
141	events.	374	events.
142		375
143	Each watcher type has its associated bit in revents, so you can use the	376	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	377	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,	378	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	379	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	380	(which can set both EV::READ and EV::WRITE bits).
148	uses EV::TIMEOUT).
149		381
150	In the rare case where one wants to create a watcher but not start it at	382	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	383	the same time, each constructor has a variant with a trailing C<_ns> in
152	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.	384	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
153		385
154	Please note that a watcher will automatically be stopped when the watcher	386	Please note that a watcher will automatically be stopped when the watcher
155	object is returned, so you I<need> to keep the watcher objects returned by	387	object is destroyed, so you I<need> to keep the watcher objects returned by
156	the constructors.	388	the constructors.
157		389
158	=head2 WATCHER TYPES	390	Also, all methods changing some aspect of a watcher (->set, ->priority,
		391	->fh and so on) automatically stop and start it again if it is active,
		392	which means pending events get lost.
159		393
160	Now lets move to the existing watcher types and asociated methods.	394	=head2 COMMON WATCHER METHODS
161		395
162	The following methods are available for all watchers. Then followes a	396	This section lists methods common to all watchers.
163	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
164	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
165	any type-specific methods (if any).
166		397
167	=over 4	398	=over 4
168		399
169	=item $w->start	400	=item $w->start
170		401
…		…
174		405
175	=item $w->stop	406	=item $w->stop
176		407
177	Stop a watcher if it is active. Also clear any pending events (events that	408	Stop a watcher if it is active. Also clear any pending events (events that
178	have been received but that didn't yet result in a callback invocation),	409	have been received but that didn't yet result in a callback invocation),
179	regardless of wether the watcher was active or not.	410	regardless of whether the watcher was active or not.
180		411
181	=item $bool = $w->is_active	412	=item $bool = $w->is_active
182		413
183	Returns true if the watcher is active, false otherwise.	414	Returns true if the watcher is active, false otherwise.
184		415
		416	=item $current_data = $w->data
		417
		418	=item $old_data = $w->data ($new_data)
		419
		420	Queries a freely usable data scalar on the watcher and optionally changes
		421	it. This is a way to associate custom data with a watcher:
		422
		423	my $w = EV::timer 60, 0, sub {
		424	warn $_[0]->data;
		425	};
		426	$w->data ("print me!");
		427
185	=item $current_cb = $w->cb	428	=item $current_cb = $w->cb
186		429
187	=item $old_cb = $w->cb ($new_cb)	430	=item $old_cb = $w->cb ($new_cb)
188		431
189	Queries the callback on the watcher and optionally changes it. You cna do	432	Queries the callback on the watcher and optionally changes it. You can do
190	this at any time.	433	this at any time without the watcher restarting.
191		434
		435	=item $current_priority = $w->priority
		436
		437	=item $old_priority = $w->priority ($new_priority)
		438
		439	Queries the priority on the watcher and optionally changes it. Pending
		440	watchers with higher priority will be invoked first. The valid range of
		441	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		442	-2). If the priority is outside this range it will automatically be
		443	normalised to the nearest valid priority.
		444
		445	The default priority of any newly-created watcher is 0.
		446
		447	Note that the priority semantics have not yet been fleshed out and are
		448	subject to almost certain change.
		449
192	=item $w->trigger ($revents)	450	=item $w->invoke ($revents)
193		451
194	Call the callback now with the given event mask.	452	Call the callback now with the given event mask.
195		453
		454	=item $w->feed_event ($revents)
		455
		456	Feed some events on this watcher into EV. EV will react to this call as if
		457	the watcher had received the given C<$revents> mask.
		458
		459	=item $revents = $w->clear_pending
		460
		461	If the watcher is pending, this function clears its pending status and
		462	returns its C<$revents> bitset (as if its callback was invoked). If the
		463	watcher isn't pending it does nothing and returns C<0>.
		464
		465	=item $previous_state = $w->keepalive ($bool)
		466
		467	Normally, C<EV::loop> will return when there are no active watchers
		468	(which is a "deadlock" because no progress can be made anymore). This is
		469	convenient because it allows you to start your watchers (and your jobs),
		470	call C<EV::loop> once and when it returns you know that all your jobs are
		471	finished (or they forgot to register some watchers for their task :).
		472
		473	Sometimes, however, this gets in your way, for example when the module
		474	that calls C<EV::loop> (usually the main program) is not the same module
		475	as a long-living watcher (for example a DNS client module written by
		476	somebody else even). Then you might want any outstanding requests to be
		477	handled, but you would not want to keep C<EV::loop> from returning just
		478	because you happen to have this long-running UDP port watcher.
		479
		480	In this case you can clear the keepalive status, which means that even
		481	though your watcher is active, it won't keep C<EV::loop> from returning.
		482
		483	The initial value for keepalive is true (enabled), and you can change it
		484	any time.
		485
		486	Example: Register an I/O watcher for some UDP socket but do not keep the
		487	event loop from running just because of that watcher.
		488
		489	my $udp_socket = ...
		490	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		491	$udp_watcher->keepalive (0);
		492
		493	=item $loop = $w->loop
		494
		495	Return the loop that this watcher is attached to.
		496
		497	=back
		498
		499
		500	=head1 WATCHER TYPES
		501
		502	Each of the following subsections describes a single watcher type.
		503
		504	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		505
		506	=over 4
196		507
197	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	508	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
198		509
199	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	510	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
200		511
		512	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		513
		514	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		515
201	As long as the returned watcher object is alive, call the C<$callback>	516	As long as the returned watcher object is alive, call the C<$callback>
202	when the events specified in C<$eventmask>.	517	when at least one of events specified in C<$eventmask> occurs.
203		518
204	The $eventmask can be one or more of these constants ORed together:	519	The $eventmask can be one or more of these constants ORed together:
205		520
206	EV::READ wait until read() wouldn't block anymore	521	EV::READ wait until read() wouldn't block anymore
207	EV::WRITE wait until write() wouldn't block anymore	522	EV::WRITE wait until write() wouldn't block anymore
…		…
223		538
224	=item $old_eventmask = $w->events ($new_eventmask)	539	=item $old_eventmask = $w->events ($new_eventmask)
225		540
226	Returns the previously set event mask and optionally set a new one.	541	Returns the previously set event mask and optionally set a new one.
227		542
		543	=back
		544
		545
		546	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		547
		548	=over 4
228		549
229	=item $w = EV::timer $after, $repeat, $callback	550	=item $w = EV::timer $after, $repeat, $callback
230		551
231	=item $w = EV::timer_ns $after, $repeat, $callback	552	=item $w = EV::timer_ns $after, $repeat, $callback
232		553
233	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	554	=item $w = $loop->timer ($after, $repeat, $callback)
234	the timer will be restarted (with the $repeat value as $after) after the	555
235	callback returns.	556	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		557
		558	Calls the callback after C<$after> seconds (which may be fractional). If
		559	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		560	value as $after) after the callback returns.
236		561
237	This means that the callback would be called roughly after C<$after>	562	This means that the callback would be called roughly after C<$after>
238	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	563	seconds, and then every C<$repeat> seconds. The timer does his best not
239	callback processing is not taken into account, so the timer will slowly	564	to drift, but it will not invoke the timer more often then once per event
240	drift. If that isn't acceptable, look at EV::periodic.	565	loop iteration, and might drift in other cases. If that isn't acceptable,
		566	look at EV::periodic, which can provide long-term stable timers.
241		567
242	The timer is based on a monotonic clock, that is if somebody is sitting	568	The timer is based on a monotonic clock, that is, if somebody is sitting
243	in front of the machine while the timer is running and changes the system	569	in front of the machine while the timer is running and changes the system
244	clock, the timer will nevertheless run (roughly) the same time.	570	clock, the timer will nevertheless run (roughly) the same time.
245		571
246	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	572	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
247		573
248	=item $w->set ($after, $repeat)	574	=item $w->set ($after, $repeat)
249		575
250	Reconfigures the watcher, see the constructor above for details. Can be at	576	Reconfigures the watcher, see the constructor above for details. Can be called at
251	any time.	577	any time.
252		578
253	=item $w->again	579	=item $w->again
254		580
255	Similar to the C<start> method, but has special semantics for repeating timers:	581	Similar to the C<start> method, but has special semantics for repeating timers:
		582
		583	If the timer is active and non-repeating, it will be stopped.
256		584
257	If the timer is active and repeating, reset the timeout to occur	585	If the timer is active and repeating, reset the timeout to occur
258	C<$repeat> seconds after now.	586	C<$repeat> seconds after now.
259		587
260	If the timer is active and non-repeating, it will be stopped.
261
262	If the timer is in active and repeating, start it.	588	If the timer is inactive and repeating, start it using the repeat value.
263		589
264	Otherwise do nothing.	590	Otherwise do nothing.
265		591
266	This behaviour is useful when you have a timeout for some IO	592	This behaviour is useful when you have a timeout for some IO
267	operation. You create a timer object with the same value for C<$after> and	593	operation. You create a timer object with the same value for C<$after> and
268	C<$repeat>, and then, in the read/write watcher, run the C<again> method	594	C<$repeat>, and then, in the read/write watcher, run the C<again> method
269	on the timeout.	595	on the timeout.
270		596
		597	=back
271		598
		599
		600	=head3 PERIODIC WATCHERS - to cron or not to cron?
		601
		602	=over 4
		603
272	=item $w = EV::periodic $at, $interval, $callback	604	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
273		605
274	=item $w = EV::periodic_ns $at, $interval, $callback	606	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
275		607
276	Similar to EV::timer, but the time is given as an absolute point in time	608	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
277	(C<$at>), plus an optional C<$interval>.
278		609
279	If the C<$interval> is zero, then the callback will be called at the time	610	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
280	C<$at> if that is in the future, or as soon as possible if it is in the
281	past. It will not automatically repeat.
282		611
283	If the C<$interval> is nonzero, then the watcher will always be scheduled	612	Similar to EV::timer, but is not based on relative timeouts but on
284	to time out at the next C<$at + N * $interval> time.	613	absolute times. Apart from creating "simple" timers that trigger "at" the
		614	specified time, it can also be used for non-drifting absolute timers and
		615	more complex, cron-like, setups that are not adversely affected by time
		616	jumps (i.e. when the system clock is changed by explicit date -s or other
		617	means such as ntpd). It is also the most complex watcher type in EV.
285		618
286	This can be used to schedule a callback to run at very regular intervals,	619	It has three distinct "modes":
287	as long as the processing time is less then the interval (otherwise	620
288	obviously events will be skipped).	621	=over 4
		622
		623	=item * absolute timer ($interval = $reschedule_cb = 0)
		624
		625	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		626	will not adjust when a time jump occurs, that is, if it is to be run
		627	at January 1st 2011 then it will run when the system time reaches or
		628	surpasses this time.
		629
		630	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
		631
		632	In this mode the watcher will always be scheduled to time out at the
		633	next C<$at + N * $interval> time (for some integer N) and then repeat,
		634	regardless of any time jumps.
		635
		636	This can be used to create timers that do not drift with respect to system
		637	time:
		638
		639	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		640
		641	That doesn't mean there will always be 3600 seconds in between triggers,
		642	but only that the the clalback will be called when the system time shows a
		643	full hour (UTC).
289		644
290	Another way to think about it (for the mathematically inclined) is that	645	Another way to think about it (for the mathematically inclined) is that
291	EV::periodic will try to run the callback at the next possible time where	646	EV::periodic will try to run the callback in this mode at the next
292	C<$time = $at (mod $interval)>, regardless of any time jumps.	647	possible time where C<$time = $at (mod $interval)>, regardless of any time
		648	jumps.
293		649
294	This periodic timer is based on "wallclock time", that is, if the clock	650	=item * manual reschedule mode ($reschedule_cb = coderef)
295	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	651
296	the specified time. This means it will never drift (it might jitter, but	652	In this mode $interval and $at are both being ignored. Instead, each
297	it will not drift).	653	time the periodic watcher gets scheduled, the reschedule callback
		654	($reschedule_cb) will be called with the watcher as first, and the current
		655	time as second argument.
		656
		657	I<This callback MUST NOT stop or destroy this or any other periodic
		658	watcher, ever, and MUST NOT call any event loop functions or methods>. If
		659	you need to stop it, return 1e30 and stop it afterwards. You may create
		660	and start a C<EV::prepare> watcher for this task.
		661
		662	It must return the next time to trigger, based on the passed time value
		663	(that is, the lowest time value larger than or equal to to the second
		664	argument). It will usually be called just before the callback will be
		665	triggered, but might be called at other times, too.
		666
		667	This can be used to create very complex timers, such as a timer that
		668	triggers on each midnight, local time (actually 24 hours after the last
		669	midnight, to keep the example simple. If you know a way to do it correctly
		670	in about the same space (without requiring elaborate modules), drop me a
		671	note :):
		672
		673	my $daily = EV::periodic 0, 0, sub {
		674	my ($w, $now) = @_;
		675
		676	use Time::Local ();
		677	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		678	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		679	}, sub {
		680	print "it's midnight or likely shortly after, now\n";
		681	};
		682
		683	=back
298		684
299	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	685	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
300		686
301	=item $w->set ($at, $interval)	687	=item $w->set ($at, $interval, $reschedule_cb)
302		688
303	Reconfigures the watcher, see the constructor above for details. Can be at	689	Reconfigures the watcher, see the constructor above for details. Can be called at
304	any time.	690	any time.
305		691
		692	=item $w->again
		693
		694	Simply stops and starts the watcher again.
		695
		696	=item $time = $w->at
		697
		698	Return the time that the watcher is expected to trigger next.
		699
		700	=back
		701
		702
		703	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		704
		705	=over 4
306		706
307	=item $w = EV::signal $signal, $callback	707	=item $w = EV::signal $signal, $callback
308		708
309	=item $w = EV::signal_ns $signal, $callback	709	=item $w = EV::signal_ns $signal, $callback
310		710
		711	=item $w = $loop->signal ($signal, $callback)
		712
		713	=item $w = $loop->signal_ns ($signal, $callback)
		714
311	Call the callback when $signal is received (the signal can be specified	715	Call the callback when $signal is received (the signal can be specified by
312	by number or by name, just as with kill or %SIG).	716	number or by name, just as with C<kill> or C<%SIG>).
		717
		718	Only one event loop can grab a given signal - attempting to grab the same
		719	signal from two EV loops will crash the program immediately or cause data
		720	corruption.
313		721
314	EV will grab the signal for the process (the kernel only allows one	722	EV will grab the signal for the process (the kernel only allows one
315	component to receive a signal at a time) when you start a signal watcher,	723	component to receive a signal at a time) when you start a signal watcher,
316	and removes it again when you stop it. Perl does the same when you	724	and removes it again when you stop it. Perl does the same when you
317	add/remove callbacks to %SIG, so watch out.	725	add/remove callbacks to C<%SIG>, so watch out.
318		726
319	You can have as many signal watchers per signal as you want.	727	You can have as many signal watchers per signal as you want.
320		728
321	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	729	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
322		730
323	=item $w->set ($signal)	731	=item $w->set ($signal)
324		732
325	Reconfigures the watcher, see the constructor above for details. Can be at	733	Reconfigures the watcher, see the constructor above for details. Can be
326	any time.	734	called at any time.
327		735
328	=item $current_signum = $w->signal	736	=item $current_signum = $w->signal
329		737
330	=item $old_signum = $w->signal ($new_signal)	738	=item $old_signum = $w->signal ($new_signal)
331		739
332	Returns the previously set signal (always as a number not name) and	740	Returns the previously set signal (always as a number not name) and
333	optionally set a new one.	741	optionally set a new one.
334		742
		743	=back
335		744
		745
		746	=head3 CHILD WATCHERS - watch out for process status changes
		747
		748	=over 4
		749
336	=item $w = EV::child $pid, $callback	750	=item $w = EV::child $pid, $trace, $callback
337		751
338	=item $w = EV::child_ns $pid, $callback	752	=item $w = EV::child_ns $pid, $trace, $callback
		753
		754	=item $w = $loop->child ($pid, $trace, $callback)
		755
		756	=item $w = $loop->child_ns ($pid, $trace, $callback)
339		757
340	Call the callback when a status change for pid C<$pid> (or any pid	758	Call the callback when a status change for pid C<$pid> (or any pid
341	if C<$pid> is 0) has been received. More precisely: when the process	759	if C<$pid> is 0) has been received (a status change happens when the
		760	process terminates or is killed, or, when trace is true, additionally when
		761	it is stopped or continued). More precisely: when the process receives
342	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	762	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
343	changed/zombie children and call the callback.	763	changed/zombie children and call the callback.
344		764
345	Unlike all other callbacks, this callback will be called with an	765	It is valid (and fully supported) to install a child watcher after a child
346	additional third argument which is the exit status. See the C<waitpid>	766	has exited but before the event loop has started its next iteration (for
347	function for details.	767	example, first you C<fork>, then the new child process might exit, and
		768	only then do you install a child watcher in the parent for the new pid).
348		769
		770	You can access both exit (or tracing) status and pid by using the
		771	C<rstatus> and C<rpid> methods on the watcher object.
		772
349	You can have as many pid watchers per pid as you want.	773	You can have as many pid watchers per pid as you want, they will all be
		774	called.
350		775
351	The C<child_ns> variant doesn't start (activate) the newly created watcher.	776	The C<child_ns> variant doesn't start (activate) the newly created watcher.
352		777
353	=item $w->set ($pid)	778	=item $w->set ($pid, $trace)
354		779
355	Reconfigures the watcher, see the constructor above for details. Can be at	780	Reconfigures the watcher, see the constructor above for details. Can be called at
356	any time.	781	any time.
357		782
358	=item $current_pid = $w->pid	783	=item $current_pid = $w->pid
359		784
360	=item $old_pid = $w->pid ($new_pid)
361
362	Returns the previously set process id and optionally set a new one.	785	Returns the previously set process id and optionally set a new one.
363		786
		787	=item $exit_status = $w->rstatus
		788
		789	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		790	in perlfunc).
		791
		792	=item $pid = $w->rpid
		793
		794	Return the pid of the awaited child (useful when you have installed a
		795	watcher for all pids).
		796
		797	=back
		798
		799
		800	=head3 STAT WATCHERS - did the file attributes just change?
		801
		802	=over 4
		803
		804	=item $w = EV::stat $path, $interval, $callback
		805
		806	=item $w = EV::stat_ns $path, $interval, $callback
		807
		808	=item $w = $loop->stat ($path, $interval, $callback)
		809
		810	=item $w = $loop->stat_ns ($path, $interval, $callback)
		811
		812	Call the callback when a file status change has been detected on
		813	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		814	to "path does not exist" is a status change like any other.
		815
		816	The C<$interval> is a recommended polling interval for systems where
		817	OS-supported change notifications don't exist or are not supported. If
		818	you use C<0> then an unspecified default is used (which is highly
		819	recommended!), which is to be expected to be around five seconds usually.
		820
		821	This watcher type is not meant for massive numbers of stat watchers,
		822	as even with OS-supported change notifications, this can be
		823	resource-intensive.
		824
		825	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		826
		827	=item ... = $w->stat
		828
		829	This call is very similar to the perl C<stat> built-in: It stats (using
		830	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		831	well as EV's idea of the current stat values) to the values found.
		832
		833	In scalar context, a boolean is return indicating success or failure of
		834	the stat. In list context, the same 13-value list as with stat is returned
		835	(except that the blksize and blocks fields are not reliable).
		836
		837	In the case of an error, errno is set to C<ENOENT> (regardless of the
		838	actual error value) and the C<nlink> value is forced to zero (if the stat
		839	was successful then nlink is guaranteed to be non-zero).
		840
		841	See also the next two entries for more info.
		842
		843	=item ... = $w->attr
		844
		845	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		846	the values most recently detected by EV. See the next entry for more info.
		847
		848	=item ... = $w->prev
		849
		850	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		851	the previous set of values, before the change.
		852
		853	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		854	to the values found I<before> a change was detected, while C<< $w->attr >>
		855	returns the values found leading to the change detection. The difference (if any)
		856	between C<prev> and C<attr> is what triggered the callback.
		857
		858	If you did something to the filesystem object and do not want to trigger
		859	yet another change, you can call C<stat> to update EV's idea of what the
		860	current attributes are.
		861
		862	=item $w->set ($path, $interval)
		863
		864	Reconfigures the watcher, see the constructor above for details. Can be
		865	called at any time.
		866
		867	=item $current_path = $w->path
		868
		869	=item $old_path = $w->path ($new_path)
		870
		871	Returns the previously set path and optionally set a new one.
		872
		873	=item $current_interval = $w->interval
		874
		875	=item $old_interval = $w->interval ($new_interval)
		876
		877	Returns the previously set interval and optionally set a new one. Can be
		878	used to query the actual interval used.
		879
		880	=back
		881
		882
		883	=head3 IDLE WATCHERS - when you've got nothing better to do...
		884
		885	=over 4
364		886
365	=item $w = EV::idle $callback	887	=item $w = EV::idle $callback
366		888
367	=item $w = EV::idle_ns $callback	889	=item $w = EV::idle_ns $callback
368		890
369	Call the callback when there are no pending io, timer/periodic, signal or	891	=item $w = $loop->idle ($callback)
370	child events, i.e. when the process is idle.	892
		893	=item $w = $loop->idle_ns ($callback)
		894
		895	Call the callback when there are no other pending watchers of the same or
		896	higher priority (excluding check, prepare and other idle watchers of the
		897	same or lower priority, of course). They are called idle watchers because
		898	when the watcher is the highest priority pending event in the process, the
		899	process is considered to be idle at that priority.
		900
		901	If you want a watcher that is only ever called when I<no> other events are
		902	outstanding you have to set the priority to C<EV::MINPRI>.
371		903
372	The process will not block as long as any idle watchers are active, and	904	The process will not block as long as any idle watchers are active, and
373	they will be called repeatedly until stopped.	905	they will be called repeatedly until stopped.
374		906
		907	For example, if you have idle watchers at priority C<0> and C<1>, and
		908	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		909	and the I/O watcher will always run when ready. Only when the idle watcher
		910	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		911	pending with the C<0>-priority idle watcher be invoked.
		912
375	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	913	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
376		914
		915	=back
		916
		917
		918	=head3 PREPARE WATCHERS - customise your event loop!
		919
		920	=over 4
377		921
378	=item $w = EV::prepare $callback	922	=item $w = EV::prepare $callback
379		923
380	=item $w = EV::prepare_ns $callback	924	=item $w = EV::prepare_ns $callback
		925
		926	=item $w = $loop->prepare ($callback)
		927
		928	=item $w = $loop->prepare_ns ($callback)
381		929
382	Call the callback just before the process would block. You can still	930	Call the callback just before the process would block. You can still
383	create/modify any watchers at this point.	931	create/modify any watchers at this point.
384		932
385	See the EV::check watcher, below, for explanations and an example.	933	See the EV::check watcher, below, for explanations and an example.
386		934
387	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	935	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
388		936
		937	=back
		938
		939
		940	=head3 CHECK WATCHERS - customise your event loop even more!
		941
		942	=over 4
389		943
390	=item $w = EV::check $callback	944	=item $w = EV::check $callback
391		945
392	=item $w = EV::check_ns $callback	946	=item $w = EV::check_ns $callback
		947
		948	=item $w = $loop->check ($callback)
		949
		950	=item $w = $loop->check_ns ($callback)
393		951
394	Call the callback just after the process wakes up again (after it has	952	Call the callback just after the process wakes up again (after it has
395	gathered events), but before any other callbacks have been invoked.	953	gathered events), but before any other callbacks have been invoked.
396		954
397	This is used to integrate other event-based software into the EV	955	This is used to integrate other event-based software into the EV
…		…
405	# do nothing unless active	963	# do nothing unless active
406	$dispatcher->{_event_queue_h}	964	$dispatcher->{_event_queue_h}
407	or return;	965	or return;
408		966
409	# make the dispatcher handle any outstanding stuff	967	# make the dispatcher handle any outstanding stuff
		968	... not shown
410		969
411	# create an IO watcher for each and every socket	970	# create an I/O watcher for each and every socket
412	@snmp_watcher = (	971	@snmp_watcher = (
413	(map { EV::io $_, EV::READ, sub { } }	972	(map { EV::io $_, EV::READ, sub { } }
414	keys %{ $dispatcher->{_descriptors} }),	973	keys %{ $dispatcher->{_descriptors} }),
		974
		975	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		976	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		977	0, sub { },
415	);	978	);
416
417	# if there are any timeouts, also create a timer
418	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
419	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
420	};	979	};
421		980
422	The callbacks are irrelevant, the only purpose of those watchers is	981	The callbacks are irrelevant (and are not even being called), the
423	to wake up the process as soon as one of those events occurs (socket	982	only purpose of those watchers is to wake up the process as soon as
424	readable, or timer timed out). The corresponding EV::check watcher will then	983	one of those events occurs (socket readable, or timer timed out). The
425	clean up:	984	corresponding EV::check watcher will then clean up:
426		985
427	our $snmp_check = EV::check sub {	986	our $snmp_check = EV::check sub {
428	# destroy all watchers	987	# destroy all watchers
429	@snmp_watcher = ();	988	@snmp_watcher = ();
430		989
431	# make the dispatcher handle any new stuff	990	# make the dispatcher handle any new stuff
		991	... not shown
432	};	992	};
433		993
434	The callbacks of the created watchers will not be called as the watchers	994	The callbacks of the created watchers will not be called as the watchers
435	are destroyed before this cna happen (remember EV::check gets called	995	are destroyed before this can happen (remember EV::check gets called
436	first).	996	first).
437		997
438	The C<check_ns> variant doesn't start (activate) the newly created watcher.	998	The C<check_ns> variant doesn't start (activate) the newly created watcher.
439		999
440	=back	1000	=back
441		1001
		1002
		1003	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		1004
		1005	Fork watchers are called when a C<fork ()> was detected. The invocation
		1006	is done before the event loop blocks next and before C<check> watchers
		1007	are being called, and only in the child after the fork.
		1008
		1009	=over 4
		1010
		1011	=item $w = EV::fork $callback
		1012
		1013	=item $w = EV::fork_ns $callback
		1014
		1015	=item $w = $loop->fork ($callback)
		1016
		1017	=item $w = $loop->fork_ns ($callback)
		1018
		1019	Call the callback before the event loop is resumed in the child process
		1020	after a fork.
		1021
		1022	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		1023
		1024	=back
		1025
		1026
		1027	=head3 EMBED WATCHERS - when one backend isn't enough...
		1028
		1029	This is a rather advanced watcher type that lets you embed one event loop
		1030	into another (currently only IO events are supported in the embedded
		1031	loop, other types of watchers might be handled in a delayed or incorrect
		1032	fashion and must not be used).
		1033
		1034	See the libev documentation at
		1035	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1036	(locally installed as F<EV::libev>) for more details.
		1037
		1038	In short, this watcher is most useful on BSD systems without working
		1039	kqueue to still be able to handle a large number of sockets:
		1040
		1041	my $socket_loop;
		1042
		1043	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1044	if (
		1045	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1046	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1047	) {
		1048	# use kqueue for sockets
		1049	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1050	}
		1051
		1052	# use the default loop otherwise
		1053	$socket_loop \|\|= EV::default_loop;
		1054
		1055	=over 4
		1056
		1057	=item $w = EV::embed $otherloop[, $callback]
		1058
		1059	=item $w = EV::embed_ns $otherloop[, $callback]
		1060
		1061	=item $w = $loop->embed ($otherloop[, $callback])
		1062
		1063	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1064
		1065	Call the callback when the embedded event loop (C<$otherloop>) has any
		1066	I/O activity. The C<$callback> is optional: if it is missing, then the
		1067	embedded event loop will be managed automatically (which is recommended),
		1068	otherwise you have to invoke C<sweep> yourself.
		1069
		1070	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1071
		1072	=back
		1073
		1074	=head3 ASYNC WATCHERS - how to wake up another event loop
		1075
		1076	Async watchers are provided by EV, but have little use in perl directly,
		1077	as perl neither supports threads running in parallel nor direct access to
		1078	signal handlers or other contexts where they could be of value.
		1079
		1080	It is, however, possible to use them from the XS level.
		1081
		1082	Please see the libev documentation for further details.
		1083
		1084	=over 4
		1085
		1086	=item $w = EV::async $callback
		1087
		1088	=item $w = EV::async_ns $callback
		1089
		1090	=item $w->send
		1091
		1092	=item $bool = $w->async_pending
		1093
		1094	=back
		1095
		1096
		1097	=head1 PERL SIGNALS
		1098
		1099	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1100	with EV is as the same as any other C library: Perl-signals will only be
		1101	handled when Perl runs, which means your signal handler might be invoked
		1102	only the next time an event callback is invoked.
		1103
		1104	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1105	ensure proper operations with regards to other event watchers.
		1106
		1107	If you cannot do this for whatever reason, you can also force a watcher
		1108	to be called on every event loop iteration by installing a C<EV::check>
		1109	watcher:
		1110
		1111	my $async_check = EV::check sub { };
		1112
		1113	This ensures that perl gets into control for a short time to handle any
		1114	pending signals, and also ensures (slightly) slower overall operation.
		1115
442	=head1 THREADS	1116	=head1 ITHREADS
443		1117
444	Threads are not supported by this in any way. Perl pseudo-threads is evil	1118	Ithreads are not supported by this module in any way. Perl pseudo-threads
445	stuff and must die.	1119	is evil stuff and must die. Real threads as provided by Coro are fully
		1120	supported (and enhanced support is available via L<Coro::EV>).
		1121
		1122	=head1 FORK
		1123
		1124	Most of the "improved" event delivering mechanisms of modern operating
		1125	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1126	not supported and usually destructive). Libev makes it possible to work
		1127	around this by having a function that recreates the kernel state after
		1128	fork in the child.
		1129
		1130	On non-win32 platforms, this module requires the pthread_atfork
		1131	functionality to do this automatically for you. This function is quite
		1132	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1133	negligible, because everything the function currently does is set a flag
		1134	that is checked only when the event loop gets used the next time, so when
		1135	you do fork but not use EV, the overhead is minimal.
		1136
		1137	On win32, there is no notion of fork so all this doesn't apply, of course.
446		1138
447	=cut	1139	=cut
448		1140
449	our $DIED = sub {	1141	our $DIED = sub {
450	warn "EV: error in callback (ignoring): $@";	1142	warn "EV: error in callback (ignoring): $@";
451	};	1143	};
452		1144
453	init;	1145	default_loop
454		1146	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
455	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
456		1147
457	1;	1148	1;
458		1149
459	=head1 SEE ALSO	1150	=head1 SEE ALSO
460		1151
461	L<EV::DNS>, L<EV::AnyEvent>.	1152	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1153	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1154	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1155	event-loop agnostic and portable event driven programming.
462		1156
463	=head1 AUTHOR	1157	=head1 AUTHOR
464		1158
465	Marc Lehmann <schmorp@schmorp.de>	1159	Marc Lehmann <schmorp@schmorp.de>
466	http://home.schmorp.de/	1160	http://home.schmorp.de/
467		1161
468	=cut	1162	=cut
469		1163

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Comparing EV/EV.pm (file contents): Revision 1.22 by root, Fri Nov 2 11:02:22 2007 UTC vs. Revision 1.127 by root, Sun Mar 28 15:48:21 2010 UTC

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Revision 1.22 by root, Fri Nov 2 11:02:22 2007 UTC vs.
Revision 1.127 by root, Sun Mar 28 15:48:21 2010 UTC