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

Comparing EV/EV.pm (file contents):
Revision 1.25 by root, Fri Nov 2 22:18:49 2007 UTC vs.
Revision 1.122 by root, Sun Jul 19 20:39:54 2009 UTC

…		…
2		2
3	EV - perl interface to libev, a high performance full-featured event loop	3	EV - perl interface to libev, a high performance full-featured event loop
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use EV;	7	use EV;
		8
		9	# TIMERS
		10
		11	my $w = EV::timer 2, 0, sub {
		12	warn "is called after 2s";
		13	};
		14
		15	my $w = EV::timer 2, 2, sub {
		16	warn "is called roughly every 2s (repeat = 2)";
		17	};
		18
		19	undef $w; # destroy event watcher again
		20
		21	my $w = EV::periodic 0, 60, 0, sub {
		22	warn "is called every minute, on the minute, exactly";
		23	};
		24
		25	# IO
		26
		27	my $w = EV::io *STDIN, EV::READ, sub {
		28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
		29	warn "stdin is readable, you entered: ", <STDIN>;
		30	};
		31
		32	# SIGNALS
		33
		34	my $w = EV::signal 'QUIT', sub {
		35	warn "sigquit received\n";
		36	};
		37
		38	# CHILD/PID STATUS CHANGES
8		39
9	# TIMERS	40	my $w = EV::child 666, 0, sub {
		41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
		43	};
10		44
11	my $w = EV::timer 2, 0, sub {	45	# STAT CHANGES
12	warn "is called after 2s";	46	my $w = EV::stat "/etc/passwd", 10, sub {
		47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
13	};	49	};
14		50
15	my $w = EV::timer 2, 1, sub {
16	warn "is called roughly every 2s (repeat = 1)";
17	};
18
19	undef $w; # destroy event watcher again
20
21	my $w = EV::periodic 0, 60, sub {
22	warn "is called every minute, on the minute, exactly";
23	};
24
25	# IO
26
27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $revents) = @_; # all callbacks get the watcher object and event mask
29	warn "stdin is readable, you entered: ", <STDIN>;
30	};
31
32	# SIGNALS
33
34	my $w = EV::signal 'QUIT', sub {
35	warn "sigquit received\n";
36	};
37
38	my $w = EV::signal 3, sub {
39	warn "sigquit received (this is GNU/Linux, right?)\n";
40	};
41
42	# CHILD/PID STATUS CHANGES
43
44	my $w = EV::child 666, sub {
45	my ($w, $revents, $status) = @_;
46	};
47
48	# MAINLOOP	51	# MAINLOOP
49	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
50	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
51	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
52		55
53	=head1 DESCRIPTION	56	=head1 DESCRIPTION
54		57
55	This module provides an interface to libev	58	This module provides an interface to libev
56	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of
		61	libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
		62	F<perldoc EV::libev>) for more subtle details on watcher semantics or some
		63	discussion on the available backends, or how to force a specific backend
		64	with C<LIBEV_FLAGS>, or just about in any case because it has much more
		65	detailed information.
		66
		67	This module is very fast and scalable. It is actually so fast that you
		68	can use it through the L<AnyEvent> module, stay portable to other event
		69	loops (if you don't rely on any watcher types not available through it)
		70	and still be faster than with any other event loop currently supported in
		71	Perl.
		72
		73	=head2 MODULE EXPORTS
		74
		75	This module does not export any symbols.
57		76
58	=cut	77	=cut
59		78
60	package EV;	79	package EV;
61		80
62	use strict;	81	use common::sense;
63		82
64	BEGIN {	83	BEGIN {
65	our $VERSION = '0.5';	84	our $VERSION = '3.7001';
66	use XSLoader;	85	use XSLoader;
67	XSLoader::load "EV", $VERSION;	86	XSLoader::load "EV", $VERSION;
68	}	87	}
69		88
70	@EV::Io::ISA =	89	@EV::IO::ISA =
71	@EV::Timer::ISA =	90	@EV::Timer::ISA =
72	@EV::Periodic::ISA =	91	@EV::Periodic::ISA =
73	@EV::Signal::ISA =	92	@EV::Signal::ISA =
		93	@EV::Child::ISA =
		94	@EV::Stat::ISA =
74	@EV::Idle::ISA =	95	@EV::Idle::ISA =
75	@EV::Prepare::ISA =	96	@EV::Prepare::ISA =
76	@EV::Check::ISA =	97	@EV::Check::ISA =
77	@EV::Child::ISA = "EV::Watcher";	98	@EV::Embed::ISA =
		99	@EV::Fork::ISA =
		100	@EV::Async::ISA =
		101	"EV::Watcher";
		102
		103	@EV::Loop::Default::ISA = "EV::Loop";
		104
		105	=head1 EVENT LOOPS
		106
		107	EV supports multiple event loops: There is a single "default event loop"
		108	that can handle everything including signals and child watchers, and any
		109	number of "dynamic event loops" that can use different backends (with
		110	various limitations), but no child and signal watchers.
		111
		112	You do not have to do anything to create the default event loop: When
		113	the module is loaded a suitable backend is selected on the premise of
		114	selecting a working backend (which for example rules out kqueue on most
		115	BSDs). Modules should, unless they have "special needs" always use the
		116	default loop as this is fastest (perl-wise), best supported by other
		117	modules (e.g. AnyEvent or Coro) and most portable event loop.
		118
		119	For specific programs you can create additional event loops dynamically.
		120
		121	If you want to take advantage of kqueue (which often works properly for
		122	sockets only) even though the default loop doesn't enable it, you can
		123	I<embed> a kqueue loop into the default loop: running the default loop
		124	will then also service the kqueue loop to some extent. See the example in
		125	the section about embed watchers for an example on how to achieve that.
		126
		127	=over 4
		128
		129	=item $loop = new EV::Loop [$flags]
		130
		131	Create a new event loop as per the specified flags. Please refer to
		132	the C<ev_loop_new ()> function description in the libev documentation
		133	(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
		134	or locally-installed as F<EV::libev> manpage) for more info.
		135
		136	The loop will automatically be destroyed when it is no longer referenced
		137	by any watcher and the loop object goes out of scope.
		138
		139	If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
		140	is recommended, as only the default event loop is protected by this
		141	module. If you I<are> embedding this loop in the default loop, this is not
		142	necessary, as C<EV::embed> automatically does the right thing on fork.
		143
		144	=item $loop->loop_fork
		145
		146	Must be called after a fork in the child, before entering or continuing
		147	the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
		148	this function automatically, at some performance loss (refer to the libev
		149	documentation).
		150
		151	=item $loop->loop_verify
		152
		153	Calls C<ev_verify> to make internal consistency checks (for debugging
		154	libev) and abort the program if any data structures were found to be
		155	corrupted.
		156
		157	=item $loop = EV::default_loop [$flags]
		158
		159	Return the default loop (which is a singleton object). Since this module
		160	already creates the default loop with default flags, specifying flags here
		161	will not have any effect unless you destroy the default loop first, which
		162	isn't supported. So in short: don't do it, and if you break it, you get to
		163	keep the pieces.
		164
		165	=back
		166
78		167
79	=head1 BASIC INTERFACE	168	=head1 BASIC INTERFACE
80		169
81	=over 4	170	=over 4
82		171
83	=item $EV::DIED	172	=item $EV::DIED
84		173
85	Must contain a reference to a function that is called when a callback	174	Must contain a reference to a function that is called when a callback
86	throws an exception (with $@ containing thr error). The default prints an	175	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	176	informative message and continues.
88		177
89	If this callback throws an exception it will be silently ignored.	178	If this callback throws an exception it will be silently ignored.
90		179
		180	=item $flags = EV::supported_backends
		181
		182	=item $flags = EV::recommended_backends
		183
		184	=item $flags = EV::embeddable_backends
		185
		186	Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this
		187	instance of EV, the set of recommended backends (supposed to be good) for
		188	this platform and the set of embeddable backends (see EMBED WATCHERS).
		189
		190	=item EV::sleep $seconds
		191
		192	Block the process for the given number of (fractional) seconds.
		193
91	=item $time = EV::time	194	=item $time = EV::time
92		195
93	Returns the current time in (fractional) seconds since the epoch.	196	Returns the current time in (fractional) seconds since the epoch.
94		197
95	=item $time = EV::now	198	=item $time = EV::now
96		199
		200	=item $time = $loop->now
		201
97	Returns the time the last event loop iteration has been started. This	202	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	203	is the time that (relative) timers are based on, and referring to it is
99	usually faster then calling EV::time.	204	usually faster then calling EV::time.
100		205
101	=item $method = EV::ev_method	206	=item EV::now_update
102		207
		208	=item $loop->now_update
		209
		210	Establishes the current time by querying the kernel, updating the time
		211	returned by C<EV::now> in the progress. This is a costly operation and
		212	is usually done automatically within C<EV::loop>.
		213
		214	This function is rarely useful, but when some event callback runs for a
		215	very long time without entering the event loop, updating libev's idea of
		216	the current time is a good idea.
		217
		218	=item EV::suspend
		219
		220	=item $loop->suspend
		221
		222	=item EV::resume
		223
		224	=item $loop->resume
		225
		226	These two functions suspend and resume a loop, for use when the loop is
		227	not used for a while and timeouts should not be processed.
		228
		229	A typical use case would be an interactive program such as a game: When
		230	the user presses C<^Z> to suspend the game and resumes it an hour later it
		231	would be best to handle timeouts as if no time had actually passed while
		232	the program was suspended. This can be achieved by calling C<suspend>
		233	in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
		234	C<resume> directly afterwards to resume timer processing.
		235
		236	Effectively, all C<timer> watchers will be delayed by the time spend
		237	between C<suspend> and C<resume>, and all C<periodic> watchers
		238	will be rescheduled (that is, they will lose any events that would have
		239	occured while suspended).
		240
		241	After calling C<suspend> you B<must not> call I<any> function on the given
		242	loop other than C<resume>, and you B<must not> call C<resume>
		243	without a previous call to C<suspend>.
		244
		245	Calling C<suspend>/C<resume> has the side effect of updating the event
		246	loop time (see C<now_update>).
		247
		248	=item $backend = EV::backend
		249
		250	=item $backend = $loop->backend
		251
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	252	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
104	or EV::METHOD_EPOLL).	253	or EV::BACKEND_EPOLL).
105		254
106	=item EV::loop [$flags]	255	=item EV::loop [$flags]
107		256
		257	=item $loop->loop ([$flags])
		258
108	Begin checking for events and calling callbacks. It returns when a	259	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	260	callback calls EV::unloop.
110		261
111	The $flags argument can be one of the following:	262	The $flags argument can be one of the following:
112		263
113	0 as above	264	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	265	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	266	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		267
117	=item EV::loop_done [$how]	268	=item EV::unloop [$how]
118		269
		270	=item $loop->unloop ([$how])
		271
119	When called with no arguments or an argument of 1, makes the innermost	272	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
120	call to EV::loop return.	273	innermost call to EV::loop return.
121		274
122	When called with an agrument of 2, all calls to EV::loop will return as	275	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
123	fast as possible.	276	fast as possible.
124		277
125	=back	278	=item $count = EV::loop_count
126		279
127	=head2 WATCHER	280	=item $count = $loop->loop_count
		281
		282	Return the number of times the event loop has polled for new
		283	events. Sometimes useful as a generation counter.
		284
		285	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		286
		287	=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
		288
		289	This function rolls together an I/O and a timer watcher for a single
		290	one-shot event without the need for managing a watcher object.
		291
		292	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		293	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		294	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		295	you do not want to wait for some I/O event, specify C<undef> for
		296	C<$fh_or_undef> and C<0> for C<$events>).
		297
		298	If timeout is C<undef> or negative, then there will be no
		299	timeout. Otherwise a EV::timer with this value will be started.
		300
		301	When an error occurs or either the timeout or I/O watcher triggers, then
		302	the callback will be called with the received event set (in general
		303	you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
		304	C<EV::WRITE> and C<EV::TIMEOUT>).
		305
		306	EV::once doesn't return anything: the watchers stay active till either
		307	of them triggers, then they will be stopped and freed, and the callback
		308	invoked.
		309
		310	=item EV::feed_fd_event ($fd, $revents)
		311
		312	=item $loop->feed_fd_event ($fd, $revents)
		313
		314	Feed an event on a file descriptor into EV. EV will react to this call as
		315	if the readyness notifications specified by C<$revents> (a combination of
		316	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		317
		318	=item EV::feed_signal_event ($signal)
		319
		320	Feed a signal event into EV. EV will react to this call as if the signal
		321	specified by C<$signal> had occured.
		322
		323	=item EV::set_io_collect_interval $time
		324
		325	=item $loop->set_io_collect_interval ($time)
		326
		327	=item EV::set_timeout_collect_interval $time
		328
		329	=item $loop->set_timeout_collect_interval ($time)
		330
		331	These advanced functions set the minimum block interval when polling for I/O events and the minimum
		332	wait interval for timer events. See the libev documentation at
		333	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
		334	(locally installed as F<EV::libev>) for a more detailed discussion.
		335
		336	=item $count = EV::pending_count
		337
		338	=item $count = $loop->pending_count
		339
		340	Returns the number of currently pending watchers.
		341
		342	=item EV::invoke_pending
		343
		344	=item $loop->invoke_pending
		345
		346	Invoke all currently pending watchers.
		347
		348	=back
		349
		350
		351	=head1 WATCHER OBJECTS
128		352
129	A watcher is an object that gets created to record your interest in some	353	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	354	event. For instance, if you want to wait for STDIN to become readable, you
131	would create an EV::io watcher for that:	355	would create an EV::io watcher for that:
132		356
133	my $watcher = EV::io *STDIN, EV::READ, sub {	357	my $watcher = EV::io *STDIN, EV::READ, sub {
134	my ($watcher, $revents) = @_;	358	my ($watcher, $revents) = @_;
135	warn "yeah, STDIN should not be readable without blocking!\n"	359	warn "yeah, STDIN should now be readable without blocking!\n"
136	};	360	};
137		361
138	All watchers can be active (waiting for events) or inactive (paused). Only	362	All watchers can be active (waiting for events) or inactive (paused). Only
139	active watchers will have their callbacks invoked. All callbacks will be	363	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	364	called with at least two arguments: the watcher and a bitmask of received
141	events.	365	events.
142		366
143	Each watcher type has its associated bit in revents, so you can use the	367	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	368	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,	369	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	370	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	371	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
148	uses EV::TIMEOUT).	372	uses EV::TIMEOUT).
149		373
150	In the rare case where one wants to create a watcher but not start it at	374	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	375	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
157		381
158	Also, all methods changing some aspect of a watcher (->set, ->priority,	382	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,	383	->fh and so on) automatically stop and start it again if it is active,
160	which means pending events get lost.	384	which means pending events get lost.
161		385
162	=head2 WATCHER TYPES	386	=head2 COMMON WATCHER METHODS
163		387
164	Now lets move to the existing watcher types and asociated methods.	388	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		389
171	=over 4	390	=over 4
172		391
173	=item $w->start	392	=item $w->start
174		393
…		…
178		397
179	=item $w->stop	398	=item $w->stop
180		399
181	Stop a watcher if it is active. Also clear any pending events (events that	400	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),	401	have been received but that didn't yet result in a callback invocation),
183	regardless of wether the watcher was active or not.	402	regardless of whether the watcher was active or not.
184		403
185	=item $bool = $w->is_active	404	=item $bool = $w->is_active
186		405
187	Returns true if the watcher is active, false otherwise.	406	Returns true if the watcher is active, false otherwise.
		407
		408	=item $current_data = $w->data
		409
		410	=item $old_data = $w->data ($new_data)
		411
		412	Queries a freely usable data scalar on the watcher and optionally changes
		413	it. This is a way to associate custom data with a watcher:
		414
		415	my $w = EV::timer 60, 0, sub {
		416	warn $_[0]->data;
		417	};
		418	$w->data ("print me!");
188		419
189	=item $current_cb = $w->cb	420	=item $current_cb = $w->cb
190		421
191	=item $old_cb = $w->cb ($new_cb)	422	=item $old_cb = $w->cb ($new_cb)
192		423
…		…
201	watchers with higher priority will be invoked first. The valid range of	432	watchers with higher priority will be invoked first. The valid range of
202	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	433	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
203	-2). If the priority is outside this range it will automatically be	434	-2). If the priority is outside this range it will automatically be
204	normalised to the nearest valid priority.	435	normalised to the nearest valid priority.
205		436
206	The default priority of any newly-created weatcher is 0.	437	The default priority of any newly-created watcher is 0.
207		438
		439	Note that the priority semantics have not yet been fleshed out and are
		440	subject to almost certain change.
		441
208	=item $w->trigger ($revents)	442	=item $w->invoke ($revents)
209		443
210	Call the callback now with the given event mask.	444	Call the callback now with the given event mask.
211		445
		446	=item $w->feed_event ($revents)
		447
		448	Feed some events on this watcher into EV. EV will react to this call as if
		449	the watcher had received the given C<$revents> mask.
		450
		451	=item $revents = $w->clear_pending
		452
		453	If the watcher is pending, this function clears its pending status and
		454	returns its C<$revents> bitset (as if its callback was invoked). If the
		455	watcher isn't pending it does nothing and returns C<0>.
		456
		457	=item $previous_state = $w->keepalive ($bool)
		458
		459	Normally, C<EV::loop> will return when there are no active watchers
		460	(which is a "deadlock" because no progress can be made anymore). This is
		461	convinient because it allows you to start your watchers (and your jobs),
		462	call C<EV::loop> once and when it returns you know that all your jobs are
		463	finished (or they forgot to register some watchers for their task :).
		464
		465	Sometimes, however, this gets in your way, for example when the module
		466	that calls C<EV::loop> (usually the main program) is not the same module
		467	as a long-living watcher (for example a DNS client module written by
		468	somebody else even). Then you might want any outstanding requests to be
		469	handled, but you would not want to keep C<EV::loop> from returning just
		470	because you happen to have this long-running UDP port watcher.
		471
		472	In this case you can clear the keepalive status, which means that even
		473	though your watcher is active, it won't keep C<EV::loop> from returning.
		474
		475	The initial value for keepalive is true (enabled), and you can change it
		476	any time.
		477
		478	Example: Register an I/O watcher for some UDP socket but do not keep the
		479	event loop from running just because of that watcher.
		480
		481	my $udp_socket = ...
		482	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		483	$udp_watcher->keepalive (0);
		484
		485	=item $loop = $w->loop
		486
		487	Return the loop that this watcher is attached to.
		488
		489	=back
		490
		491
		492	=head1 WATCHER TYPES
		493
		494	Each of the following subsections describes a single watcher type.
		495
		496	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		497
		498	=over 4
212		499
213	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	500	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
214		501
215	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	502	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
216		503
		504	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		505
		506	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		507
217	As long as the returned watcher object is alive, call the C<$callback>	508	As long as the returned watcher object is alive, call the C<$callback>
218	when the events specified in C<$eventmask>.	509	when at least one of events specified in C<$eventmask> occurs.
219		510
220	The $eventmask can be one or more of these constants ORed together:	511	The $eventmask can be one or more of these constants ORed together:
221		512
222	EV::READ wait until read() wouldn't block anymore	513	EV::READ wait until read() wouldn't block anymore
223	EV::WRITE wait until write() wouldn't block anymore	514	EV::WRITE wait until write() wouldn't block anymore
…		…
239		530
240	=item $old_eventmask = $w->events ($new_eventmask)	531	=item $old_eventmask = $w->events ($new_eventmask)
241		532
242	Returns the previously set event mask and optionally set a new one.	533	Returns the previously set event mask and optionally set a new one.
243		534
		535	=back
		536
		537
		538	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		539
		540	=over 4
244		541
245	=item $w = EV::timer $after, $repeat, $callback	542	=item $w = EV::timer $after, $repeat, $callback
246		543
247	=item $w = EV::timer_ns $after, $repeat, $callback	544	=item $w = EV::timer_ns $after, $repeat, $callback
248		545
249	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	546	=item $w = $loop->timer ($after, $repeat, $callback)
250	the timer will be restarted (with the $repeat value as $after) after the	547
251	callback returns.	548	=item $w = $loop->timer_ns ($after, $repeat, $callback)
		549
		550	Calls the callback after C<$after> seconds (which may be fractional). If
		551	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
		552	value as $after) after the callback returns.
252		553
253	This means that the callback would be called roughly after C<$after>	554	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	555	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	556	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.	557	loop iteration, and might drift in other cases. If that isn't acceptable,
		558	look at EV::periodic, which can provide long-term stable timers.
257		559
258	The timer is based on a monotonic clock, that is if somebody is sitting	560	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	561	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.	562	clock, the timer will nevertheless run (roughly) the same time.
261		563
262	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	564	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
263		565
264	=item $w->set ($after, $repeat)	566	=item $w->set ($after, $repeat)
265		567
266	Reconfigures the watcher, see the constructor above for details. Can be at	568	Reconfigures the watcher, see the constructor above for details. Can be called at
267	any time.	569	any time.
268		570
269	=item $w->again	571	=item $w->again
270		572
271	Similar to the C<start> method, but has special semantics for repeating timers:	573	Similar to the C<start> method, but has special semantics for repeating timers:
		574
		575	If the timer is active and non-repeating, it will be stopped.
272		576
273	If the timer is active and repeating, reset the timeout to occur	577	If the timer is active and repeating, reset the timeout to occur
274	C<$repeat> seconds after now.	578	C<$repeat> seconds after now.
275		579
276	If the timer is active and non-repeating, it will be stopped.
277
278	If the timer is in active and repeating, start it.	580	If the timer is inactive and repeating, start it using the repeat value.
279		581
280	Otherwise do nothing.	582	Otherwise do nothing.
281		583
282	This behaviour is useful when you have a timeout for some IO	584	This behaviour is useful when you have a timeout for some IO
283	operation. You create a timer object with the same value for C<$after> and	585	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	586	C<$repeat>, and then, in the read/write watcher, run the C<again> method
285	on the timeout.	587	on the timeout.
286		588
		589	=back
287		590
		591
		592	=head3 PERIODIC WATCHERS - to cron or not to cron?
		593
		594	=over 4
		595
288	=item $w = EV::periodic $at, $interval, $callback	596	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
289		597
290	=item $w = EV::periodic_ns $at, $interval, $callback	598	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
291		599
292	Similar to EV::timer, but the time is given as an absolute point in time	600	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
293	(C<$at>), plus an optional C<$interval>.
294		601
295	If the C<$interval> is zero, then the callback will be called at the time	602	=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		603
299	If the C<$interval> is nonzero, then the watcher will always be scheduled	604	Similar to EV::timer, but is not based on relative timeouts but on
300	to time out at the next C<$at + N * $interval> time.	605	absolute times. Apart from creating "simple" timers that trigger "at" the
		606	specified time, it can also be used for non-drifting absolute timers and
		607	more complex, cron-like, setups that are not adversely affected by time
		608	jumps (i.e. when the system clock is changed by explicit date -s or other
		609	means such as ntpd). It is also the most complex watcher type in EV.
301		610
302	This can be used to schedule a callback to run at very regular intervals,	611	It has three distinct "modes":
303	as long as the processing time is less then the interval (otherwise	612
304	obviously events will be skipped).	613	=over 4
		614
		615	=item * absolute timer ($interval = $reschedule_cb = 0)
		616
		617	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		618	will not adjust when a time jump occurs, that is, if it is to be run
		619	at January 1st 2011 then it will run when the system time reaches or
		620	surpasses this time.
		621
		622	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
		623
		624	In this mode the watcher will always be scheduled to time out at the
		625	next C<$at + N * $interval> time (for some integer N) and then repeat,
		626	regardless of any time jumps.
		627
		628	This can be used to create timers that do not drift with respect to system
		629	time:
		630
		631	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		632
		633	That doesn't mean there will always be 3600 seconds in between triggers,
		634	but only that the the clalback will be called when the system time shows a
		635	full hour (UTC).
305		636
306	Another way to think about it (for the mathematically inclined) is that	637	Another way to think about it (for the mathematically inclined) is that
307	EV::periodic will try to run the callback at the next possible time where	638	EV::periodic will try to run the callback in this mode at the next
308	C<$time = $at (mod $interval)>, regardless of any time jumps.	639	possible time where C<$time = $at (mod $interval)>, regardless of any time
		640	jumps.
309		641
310	This periodic timer is based on "wallclock time", that is, if the clock	642	=item * manual reschedule mode ($reschedule_cb = coderef)
311	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	643
312	the specified time. This means it will never drift (it might jitter, but	644	In this mode $interval and $at are both being ignored. Instead, each
313	it will not drift).	645	time the periodic watcher gets scheduled, the reschedule callback
		646	($reschedule_cb) will be called with the watcher as first, and the current
		647	time as second argument.
		648
		649	I<This callback MUST NOT stop or destroy this or any other periodic
		650	watcher, ever, and MUST NOT call any event loop functions or methods>. If
		651	you need to stop it, return 1e30 and stop it afterwards. You may create
		652	and start a C<EV::prepare> watcher for this task.
		653
		654	It must return the next time to trigger, based on the passed time value
		655	(that is, the lowest time value larger than or equal to to the second
		656	argument). It will usually be called just before the callback will be
		657	triggered, but might be called at other times, too.
		658
		659	This can be used to create very complex timers, such as a timer that
		660	triggers on each midnight, local time (actually 24 hours after the last
		661	midnight, to keep the example simple. If you know a way to do it correctly
		662	in about the same space (without requiring elaborate modules), drop me a
		663	note :):
		664
		665	my $daily = EV::periodic 0, 0, sub {
		666	my ($w, $now) = @_;
		667
		668	use Time::Local ();
		669	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		670	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		671	}, sub {
		672	print "it's midnight or likely shortly after, now\n";
		673	};
		674
		675	=back
314		676
315	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	677	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
316		678
317	=item $w->set ($at, $interval)	679	=item $w->set ($at, $interval, $reschedule_cb)
318		680
319	Reconfigures the watcher, see the constructor above for details. Can be at	681	Reconfigures the watcher, see the constructor above for details. Can be called at
320	any time.	682	any time.
321		683
		684	=item $w->again
		685
		686	Simply stops and starts the watcher again.
		687
		688	=item $time = $w->at
		689
		690	Return the time that the watcher is expected to trigger next.
		691
		692	=back
		693
		694
		695	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		696
		697	=over 4
322		698
323	=item $w = EV::signal $signal, $callback	699	=item $w = EV::signal $signal, $callback
324		700
325	=item $w = EV::signal_ns $signal, $callback	701	=item $w = EV::signal_ns $signal, $callback
326		702
		703	=item $w = $loop->signal ($signal, $callback)
		704
		705	=item $w = $loop->signal_ns ($signal, $callback)
		706
327	Call the callback when $signal is received (the signal can be specified	707	Call the callback when $signal is received (the signal can be specified by
328	by number or by name, just as with kill or %SIG).	708	number or by name, just as with C<kill> or C<%SIG>).
		709
		710	Only one event loop can grab a given signal - attempting to grab the same
		711	signal from two EV loops will crash the program immediately or cause data
		712	corruption.
329		713
330	EV will grab the signal for the process (the kernel only allows one	714	EV will grab the signal for the process (the kernel only allows one
331	component to receive a signal at a time) when you start a signal watcher,	715	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	716	and removes it again when you stop it. Perl does the same when you
333	add/remove callbacks to %SIG, so watch out.	717	add/remove callbacks to C<%SIG>, so watch out.
334		718
335	You can have as many signal watchers per signal as you want.	719	You can have as many signal watchers per signal as you want.
336		720
337	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	721	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
338		722
339	=item $w->set ($signal)	723	=item $w->set ($signal)
340		724
341	Reconfigures the watcher, see the constructor above for details. Can be at	725	Reconfigures the watcher, see the constructor above for details. Can be
342	any time.	726	called at any time.
343		727
344	=item $current_signum = $w->signal	728	=item $current_signum = $w->signal
345		729
346	=item $old_signum = $w->signal ($new_signal)	730	=item $old_signum = $w->signal ($new_signal)
347		731
348	Returns the previously set signal (always as a number not name) and	732	Returns the previously set signal (always as a number not name) and
349	optionally set a new one.	733	optionally set a new one.
350		734
		735	=back
351		736
		737
		738	=head3 CHILD WATCHERS - watch out for process status changes
		739
		740	=over 4
		741
352	=item $w = EV::child $pid, $callback	742	=item $w = EV::child $pid, $trace, $callback
353		743
354	=item $w = EV::child_ns $pid, $callback	744	=item $w = EV::child_ns $pid, $trace, $callback
		745
		746	=item $w = $loop->child ($pid, $trace, $callback)
		747
		748	=item $w = $loop->child_ns ($pid, $trace, $callback)
355		749
356	Call the callback when a status change for pid C<$pid> (or any pid	750	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	751	if C<$pid> is 0) has been received (a status change happens when the
		752	process terminates or is killed, or, when trace is true, additionally when
		753	it is stopped or continued). More precisely: when the process receives
358	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	754	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
359	changed/zombie children and call the callback.	755	changed/zombie children and call the callback.
360		756
361	Unlike all other callbacks, this callback will be called with an	757	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>	758	has exited but before the event loop has started its next iteration (for
363	function for details.	759	example, first you C<fork>, then the new child process might exit, and
		760	only then do you install a child watcher in the parent for the new pid).
364		761
		762	You can access both exit (or tracing) status and pid by using the
		763	C<rstatus> and C<rpid> methods on the watcher object.
		764
365	You can have as many pid watchers per pid as you want.	765	You can have as many pid watchers per pid as you want, they will all be
		766	called.
366		767
367	The C<child_ns> variant doesn't start (activate) the newly created watcher.	768	The C<child_ns> variant doesn't start (activate) the newly created watcher.
368		769
369	=item $w->set ($pid)	770	=item $w->set ($pid, $trace)
370		771
371	Reconfigures the watcher, see the constructor above for details. Can be at	772	Reconfigures the watcher, see the constructor above for details. Can be called at
372	any time.	773	any time.
373		774
374	=item $current_pid = $w->pid	775	=item $current_pid = $w->pid
375		776
376	=item $old_pid = $w->pid ($new_pid)
377
378	Returns the previously set process id and optionally set a new one.	777	Returns the previously set process id and optionally set a new one.
379		778
		779	=item $exit_status = $w->rstatus
		780
		781	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		782	in perlfunc).
		783
		784	=item $pid = $w->rpid
		785
		786	Return the pid of the awaited child (useful when you have installed a
		787	watcher for all pids).
		788
		789	=back
		790
		791
		792	=head3 STAT WATCHERS - did the file attributes just change?
		793
		794	=over 4
		795
		796	=item $w = EV::stat $path, $interval, $callback
		797
		798	=item $w = EV::stat_ns $path, $interval, $callback
		799
		800	=item $w = $loop->stat ($path, $interval, $callback)
		801
		802	=item $w = $loop->stat_ns ($path, $interval, $callback)
		803
		804	Call the callback when a file status change has been detected on
		805	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		806	to "path does not exist" is a status change like any other.
		807
		808	The C<$interval> is a recommended polling interval for systems where
		809	OS-supported change notifications don't exist or are not supported. If
		810	you use C<0> then an unspecified default is used (which is highly
		811	recommended!), which is to be expected to be around five seconds usually.
		812
		813	This watcher type is not meant for massive numbers of stat watchers,
		814	as even with OS-supported change notifications, this can be
		815	resource-intensive.
		816
		817	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		818
		819	=item ... = $w->stat
		820
		821	This call is very similar to the perl C<stat> built-in: It stats (using
		822	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		823	well as EV's idea of the current stat values) to the values found.
		824
		825	In scalar context, a boolean is return indicating success or failure of
		826	the stat. In list context, the same 13-value list as with stat is returned
		827	(except that the blksize and blocks fields are not reliable).
		828
		829	In the case of an error, errno is set to C<ENOENT> (regardless of the
		830	actual error value) and the C<nlink> value is forced to zero (if the stat
		831	was successful then nlink is guaranteed to be non-zero).
		832
		833	See also the next two entries for more info.
		834
		835	=item ... = $w->attr
		836
		837	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		838	the values most recently detected by EV. See the next entry for more info.
		839
		840	=item ... = $w->prev
		841
		842	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		843	the previous set of values, before the change.
		844
		845	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		846	to the values found I<before> a change was detected, while C<< $w->attr >>
		847	returns the values found leading to the change detection. The difference (if any)
		848	between C<prev> and C<attr> is what triggered the callback.
		849
		850	If you did something to the filesystem object and do not want to trigger
		851	yet another change, you can call C<stat> to update EV's idea of what the
		852	current attributes are.
		853
		854	=item $w->set ($path, $interval)
		855
		856	Reconfigures the watcher, see the constructor above for details. Can be
		857	called at any time.
		858
		859	=item $current_path = $w->path
		860
		861	=item $old_path = $w->path ($new_path)
		862
		863	Returns the previously set path and optionally set a new one.
		864
		865	=item $current_interval = $w->interval
		866
		867	=item $old_interval = $w->interval ($new_interval)
		868
		869	Returns the previously set interval and optionally set a new one. Can be
		870	used to query the actual interval used.
		871
		872	=back
		873
		874
		875	=head3 IDLE WATCHERS - when you've got nothing better to do...
		876
		877	=over 4
380		878
381	=item $w = EV::idle $callback	879	=item $w = EV::idle $callback
382		880
383	=item $w = EV::idle_ns $callback	881	=item $w = EV::idle_ns $callback
384		882
385	Call the callback when there are no pending io, timer/periodic, signal or	883	=item $w = $loop->idle ($callback)
386	child events, i.e. when the process is idle.	884
		885	=item $w = $loop->idle_ns ($callback)
		886
		887	Call the callback when there are no other pending watchers of the same or
		888	higher priority (excluding check, prepare and other idle watchers of the
		889	same or lower priority, of course). They are called idle watchers because
		890	when the watcher is the highest priority pending event in the process, the
		891	process is considered to be idle at that priority.
		892
		893	If you want a watcher that is only ever called when I<no> other events are
		894	outstanding you have to set the priority to C<EV::MINPRI>.
387		895
388	The process will not block as long as any idle watchers are active, and	896	The process will not block as long as any idle watchers are active, and
389	they will be called repeatedly until stopped.	897	they will be called repeatedly until stopped.
390		898
		899	For example, if you have idle watchers at priority C<0> and C<1>, and
		900	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		901	and the I/O watcher will always run when ready. Only when the idle watcher
		902	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		903	pending with the C<0>-priority idle watcher be invoked.
		904
391	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	905	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
392		906
		907	=back
		908
		909
		910	=head3 PREPARE WATCHERS - customise your event loop!
		911
		912	=over 4
393		913
394	=item $w = EV::prepare $callback	914	=item $w = EV::prepare $callback
395		915
396	=item $w = EV::prepare_ns $callback	916	=item $w = EV::prepare_ns $callback
		917
		918	=item $w = $loop->prepare ($callback)
		919
		920	=item $w = $loop->prepare_ns ($callback)
397		921
398	Call the callback just before the process would block. You can still	922	Call the callback just before the process would block. You can still
399	create/modify any watchers at this point.	923	create/modify any watchers at this point.
400		924
401	See the EV::check watcher, below, for explanations and an example.	925	See the EV::check watcher, below, for explanations and an example.
402		926
403	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	927	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
404		928
		929	=back
		930
		931
		932	=head3 CHECK WATCHERS - customise your event loop even more!
		933
		934	=over 4
405		935
406	=item $w = EV::check $callback	936	=item $w = EV::check $callback
407		937
408	=item $w = EV::check_ns $callback	938	=item $w = EV::check_ns $callback
		939
		940	=item $w = $loop->check ($callback)
		941
		942	=item $w = $loop->check_ns ($callback)
409		943
410	Call the callback just after the process wakes up again (after it has	944	Call the callback just after the process wakes up again (after it has
411	gathered events), but before any other callbacks have been invoked.	945	gathered events), but before any other callbacks have been invoked.
412		946
413	This is used to integrate other event-based software into the EV	947	This is used to integrate other event-based software into the EV
…		…
421	# do nothing unless active	955	# do nothing unless active
422	$dispatcher->{_event_queue_h}	956	$dispatcher->{_event_queue_h}
423	or return;	957	or return;
424		958
425	# make the dispatcher handle any outstanding stuff	959	# make the dispatcher handle any outstanding stuff
		960	... not shown
426		961
427	# create an IO watcher for each and every socket	962	# create an I/O watcher for each and every socket
428	@snmp_watcher = (	963	@snmp_watcher = (
429	(map { EV::io $_, EV::READ, sub { } }	964	(map { EV::io $_, EV::READ, sub { } }
430	keys %{ $dispatcher->{_descriptors} }),	965	keys %{ $dispatcher->{_descriptors} }),
		966
		967	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		968	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		969	0, sub { },
431	);	970	);
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	};	971	};
437		972
438	The callbacks are irrelevant, the only purpose of those watchers is	973	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	974	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	975	one of those events occurs (socket readable, or timer timed out). The
441	clean up:	976	corresponding EV::check watcher will then clean up:
442		977
443	our $snmp_check = EV::check sub {	978	our $snmp_check = EV::check sub {
444	# destroy all watchers	979	# destroy all watchers
445	@snmp_watcher = ();	980	@snmp_watcher = ();
446		981
447	# make the dispatcher handle any new stuff	982	# make the dispatcher handle any new stuff
		983	... not shown
448	};	984	};
449		985
450	The callbacks of the created watchers will not be called as the watchers	986	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	987	are destroyed before this can happen (remember EV::check gets called
452	first).	988	first).
453		989
454	The C<check_ns> variant doesn't start (activate) the newly created watcher.	990	The C<check_ns> variant doesn't start (activate) the newly created watcher.
455		991
456	=back	992	=back
457		993
		994
		995	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		996
		997	Fork watchers are called when a C<fork ()> was detected. The invocation
		998	is done before the event loop blocks next and before C<check> watchers
		999	are being called, and only in the child after the fork.
		1000
		1001	=over 4
		1002
		1003	=item $w = EV::fork $callback
		1004
		1005	=item $w = EV::fork_ns $callback
		1006
		1007	=item $w = $loop->fork ($callback)
		1008
		1009	=item $w = $loop->fork_ns ($callback)
		1010
		1011	Call the callback before the event loop is resumed in the child process
		1012	after a fork.
		1013
		1014	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		1015
		1016	=back
		1017
		1018
		1019	=head3 EMBED WATCHERS - when one backend isn't enough...
		1020
		1021	This is a rather advanced watcher type that lets you embed one event loop
		1022	into another (currently only IO events are supported in the embedded
		1023	loop, other types of watchers might be handled in a delayed or incorrect
		1024	fashion and must not be used).
		1025
		1026	See the libev documentation at
		1027	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1028	(locally installed as F<EV::libev>) for more details.
		1029
		1030	In short, this watcher is most useful on BSD systems without working
		1031	kqueue to still be able to handle a large number of sockets:
		1032
		1033	my $socket_loop;
		1034
		1035	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1036	if (
		1037	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1038	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1039	) {
		1040	# use kqueue for sockets
		1041	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1042	}
		1043
		1044	# use the default loop otherwise
		1045	$socket_loop \|\|= EV::default_loop;
		1046
		1047	=over 4
		1048
		1049	=item $w = EV::embed $otherloop[, $callback]
		1050
		1051	=item $w = EV::embed_ns $otherloop[, $callback]
		1052
		1053	=item $w = $loop->embed ($otherloop[, $callback])
		1054
		1055	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1056
		1057	Call the callback when the embedded event loop (C<$otherloop>) has any
		1058	I/O activity. The C<$callback> is optional: if it is missing, then the
		1059	embedded event loop will be managed automatically (which is recommended),
		1060	otherwise you have to invoke C<sweep> yourself.
		1061
		1062	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1063
		1064	=back
		1065
		1066	=head3 ASYNC WATCHERS - how to wake up another event loop
		1067
		1068	Async watchers are provided by EV, but have little use in perl directly,
		1069	as perl neither supports threads running in parallel nor direct access to
		1070	signal handlers or other contexts where they could be of value.
		1071
		1072	It is, however, possible to use them from the XS level.
		1073
		1074	Please see the libev documentation for further details.
		1075
		1076	=over 4
		1077
		1078	=item $w = EV::async $callback
		1079
		1080	=item $w = EV::async_ns $callback
		1081
		1082	=item $w->send
		1083
		1084	=item $bool = $w->async_pending
		1085
		1086	=back
		1087
		1088
		1089	=head1 PERL SIGNALS
		1090
		1091	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1092	with EV is as the same as any other C library: Perl-signals will only be
		1093	handled when Perl runs, which means your signal handler might be invoked
		1094	only the next time an event callback is invoked.
		1095
		1096	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1097	ensure proper operations with regards to other event watchers.
		1098
		1099	If you cannot do this for whatever reason, you can also force a watcher
		1100	to be called on every event loop iteration by installing a C<EV::check>
		1101	watcher:
		1102
		1103	my $async_check = EV::check sub { };
		1104
		1105	This ensures that perl gets into control for a short time to handle any
		1106	pending signals, and also ensures (slightly) slower overall operation.
		1107
458	=head1 THREADS	1108	=head1 ITHREADS
459		1109
460	Threads are not supported by this in any way. Perl pseudo-threads is evil	1110	Ithreads are not supported by this module in any way. Perl pseudo-threads
461	stuff and must die.	1111	is evil stuff and must die. Real threads as provided by Coro are fully
		1112	supported (and enhanced support is available via L<Coro::EV>).
		1113
		1114	=head1 FORK
		1115
		1116	Most of the "improved" event delivering mechanisms of modern operating
		1117	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1118	not supported and usually destructive). Libev makes it possible to work
		1119	around this by having a function that recreates the kernel state after
		1120	fork in the child.
		1121
		1122	On non-win32 platforms, this module requires the pthread_atfork
		1123	functionality to do this automatically for you. This function is quite
		1124	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1125	negligible, because everything the function currently does is set a flag
		1126	that is checked only when the event loop gets used the next time, so when
		1127	you do fork but not use EV, the overhead is minimal.
		1128
		1129	On win32, there is no notion of fork so all this doesn't apply, of course.
462		1130
463	=cut	1131	=cut
464		1132
465	our $DIED = sub {	1133	our $DIED = sub {
466	warn "EV: error in callback (ignoring): $@";	1134	warn "EV: error in callback (ignoring): $@";
467	};	1135	};
468		1136
469	init;	1137	default_loop
470		1138	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
471	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
472		1139
473	1;	1140	1;
474		1141
475	=head1 SEE ALSO	1142	=head1 SEE ALSO
476		1143
477	L<EV::DNS>, L<EV::AnyEvent>.	1144	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1145	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1146	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1147	event-loop agnostic and portable event driven programming.
478		1148
479	=head1 AUTHOR	1149	=head1 AUTHOR
480		1150
481	Marc Lehmann <schmorp@schmorp.de>	1151	Marc Lehmann <schmorp@schmorp.de>
482	http://home.schmorp.de/	1152	http://home.schmorp.de/
483		1153
484	=cut	1154	=cut
485		1155

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Comparing EV/EV.pm (file contents): Revision 1.25 by root, Fri Nov 2 22:18:49 2007 UTC vs. Revision 1.122 by root, Sun Jul 19 20:39:54 2009 UTC

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Revision 1.25 by root, Fri Nov 2 22:18:49 2007 UTC vs.
Revision 1.122 by root, Sun Jul 19 20:39:54 2009 UTC