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

Comparing EV/EV.pm (file contents):
Revision 1.32 by root, Thu Nov 8 17:02:10 2007 UTC vs.
Revision 1.120 by root, Sun Jul 19 01:36:34 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 {
13	};
14
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, 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 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, $revents) = @_;	47	my ($w, $revents) = @_;
46	# my $pid = $w->rpid;	48	warn $w->path, " has changed somehow.\n";
47	my $status = $w->rstatus;
48	};	49	};
49		50
50	# MAINLOOP	51	# MAINLOOP
51	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
52	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
53	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
54		55
55	=head1 DESCRIPTION	56	=head1 DESCRIPTION
56		57
57	This module provides an interface to libev	58	This module provides an interface to libev
58	(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.
59		76
60	=cut	77	=cut
61		78
62	package EV;	79	package EV;
63		80
64	use strict;	81	use common::sense;
65		82
66	BEGIN {	83	BEGIN {
67	our $VERSION = '0.6';	84	our $VERSION = '3.8';
68	use XSLoader;	85	use XSLoader;
69	XSLoader::load "EV", $VERSION;	86	XSLoader::load "EV", $VERSION;
70	}	87	}
71		88
72	@EV::Io::ISA =	89	@EV::IO::ISA =
73	@EV::Timer::ISA =	90	@EV::Timer::ISA =
74	@EV::Periodic::ISA =	91	@EV::Periodic::ISA =
75	@EV::Signal::ISA =	92	@EV::Signal::ISA =
		93	@EV::Child::ISA =
		94	@EV::Stat::ISA =
76	@EV::Idle::ISA =	95	@EV::Idle::ISA =
77	@EV::Prepare::ISA =	96	@EV::Prepare::ISA =
78	@EV::Check::ISA =	97	@EV::Check::ISA =
79	@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
80		167
81	=head1 BASIC INTERFACE	168	=head1 BASIC INTERFACE
82		169
83	=over 4	170	=over 4
84		171
85	=item $EV::DIED	172	=item $EV::DIED
86		173
87	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
88	throws an exception (with $@ containing thr error). The default prints an	175	throws an exception (with $@ containing the error). The default prints an
89	informative message and continues.	176	informative message and continues.
90		177
91	If this callback throws an exception it will be silently ignored.	178	If this callback throws an exception it will be silently ignored.
92		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
93	=item $time = EV::time	194	=item $time = EV::time
94		195
95	Returns the current time in (fractional) seconds since the epoch.	196	Returns the current time in (fractional) seconds since the epoch.
96		197
97	=item $time = EV::now	198	=item $time = EV::now
98		199
		200	=item $time = $loop->now
		201
99	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
100	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
101	usually faster then calling EV::time.	204	usually faster then calling EV::time.
102		205
103	=item $method = EV::ev_method	206	=item EV::now_update
104		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 = $loop->backend
		251
105	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	252	Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
106	or EV::METHOD_EPOLL).	253	or EV::BACKEND_EPOLL).
107		254
108	=item EV::loop [$flags]	255	=item EV::loop [$flags]
109		256
		257	=item $loop->loop ([$flags])
		258
110	Begin checking for events and calling callbacks. It returns when a	259	Begin checking for events and calling callbacks. It returns when a
111	callback calls EV::loop_done.	260	callback calls EV::unloop.
112		261
113	The $flags argument can be one of the following:	262	The $flags argument can be one of the following:
114		263
115	0 as above	264	0 as above
116	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	265	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
117	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	266	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
118		267
119	=item EV::loop_done [$how]	268	=item EV::unloop [$how]
120		269
		270	=item $loop->unloop ([$how])
		271
121	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
122	call to EV::loop return.	273	innermost call to EV::loop return.
123		274
124	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
125	fast as possible.	276	fast as possible.
126		277
127	=back	278	=item $count = EV::loop_count
128		279
129	=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
130		352
131	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
132	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
133	would create an EV::io watcher for that:	355	would create an EV::io watcher for that:
134		356
135	my $watcher = EV::io *STDIN, EV::READ, sub {	357	my $watcher = EV::io *STDIN, EV::READ, sub {
136	my ($watcher, $revents) = @_;	358	my ($watcher, $revents) = @_;
137	warn "yeah, STDIN should not be readable without blocking!\n"	359	warn "yeah, STDIN should now be readable without blocking!\n"
138	};	360	};
139		361
140	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
141	active watchers will have their callbacks invoked. All callbacks will be	363	active watchers will have their callbacks invoked. All callbacks will be
142	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
143	events.	365	events.
144		366
145	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
146	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
147	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,
148	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
149	(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
150	uses EV::TIMEOUT).	372	uses EV::TIMEOUT).
151		373
152	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
153	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
…		…
159		381
160	Also, all methods changing some aspect of a watcher (->set, ->priority,	382	Also, all methods changing some aspect of a watcher (->set, ->priority,
161	->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,
162	which means pending events get lost.	384	which means pending events get lost.
163		385
164	=head2 WATCHER TYPES	386	=head2 COMMON WATCHER METHODS
165		387
166	Now lets move to the existing watcher types and asociated methods.	388	This section lists methods common to all watchers.
167
168	The following methods are available for all watchers. Then followes a
169	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
170	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
171	any type-specific methods (if any).
172		389
173	=over 4	390	=over 4
174		391
175	=item $w->start	392	=item $w->start
176		393
…		…
180		397
181	=item $w->stop	398	=item $w->stop
182		399
183	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
184	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),
185	regardless of wether the watcher was active or not.	402	regardless of whether the watcher was active or not.
186		403
187	=item $bool = $w->is_active	404	=item $bool = $w->is_active
188		405
189	Returns true if the watcher is active, false otherwise.	406	Returns true if the watcher is active, false otherwise.
190		407
…		…
215	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
216	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	433	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
217	-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
218	normalised to the nearest valid priority.	435	normalised to the nearest valid priority.
219		436
220	The default priority of any newly-created weatcher is 0.	437	The default priority of any newly-created watcher is 0.
221		438
		439	Note that the priority semantics have not yet been fleshed out and are
		440	subject to almost certain change.
		441
222	=item $w->trigger ($revents)	442	=item $w->invoke ($revents)
223		443
224	Call the callback now with the given event mask.	444	Call the callback now with the given event mask.
225		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
226		499
227	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	500	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
228		501
229	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	502	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
230		503
		504	=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback)
		505
		506	=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback)
		507
231	As long as the returned watcher object is alive, call the C<$callback>	508	As long as the returned watcher object is alive, call the C<$callback>
232	when the events specified in C<$eventmask>.	509	when at least one of events specified in C<$eventmask> occurs.
233		510
234	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:
235		512
236	EV::READ wait until read() wouldn't block anymore	513	EV::READ wait until read() wouldn't block anymore
237	EV::WRITE wait until write() wouldn't block anymore	514	EV::WRITE wait until write() wouldn't block anymore
…		…
253		530
254	=item $old_eventmask = $w->events ($new_eventmask)	531	=item $old_eventmask = $w->events ($new_eventmask)
255		532
256	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.
257		534
		535	=back
		536
		537
		538	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		539
		540	=over 4
258		541
259	=item $w = EV::timer $after, $repeat, $callback	542	=item $w = EV::timer $after, $repeat, $callback
260		543
261	=item $w = EV::timer_ns $after, $repeat, $callback	544	=item $w = EV::timer_ns $after, $repeat, $callback
262		545
263	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	546	=item $w = $loop->timer ($after, $repeat, $callback)
264	the timer will be restarted (with the $repeat value as $after) after the	547
265	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 $after) after the callback returns.
266		553
267	This means that the callback would be called roughly after C<$after>	554	This means that the callback would be called roughly after C<$after>
268	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	555	seconds, and then every C<$repeat> seconds. The timer does his best not
269	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
270	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.
271		559
272	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
273	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
274	clock, the timer will nevertheless run (roughly) the same time.	562	clock, the timer will nevertheless run (roughly) the same time.
275		563
276	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.
277		565
278	=item $w->set ($after, $repeat)	566	=item $w->set ($after, $repeat)
279		567
280	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
281	any time.	569	any time.
282		570
283	=item $w->again	571	=item $w->again
284		572
285	Similar to the C<start> method, but has special semantics for repeating timers:	573	Similar to the C<start> method, but has special semantics for repeating timers:
		574
		575	If the timer is active and non-repeating, it will be stopped.
286		576
287	If the timer is active and repeating, reset the timeout to occur	577	If the timer is active and repeating, reset the timeout to occur
288	C<$repeat> seconds after now.	578	C<$repeat> seconds after now.
289		579
290	If the timer is active and non-repeating, it will be stopped.
291
292	If the timer is in active and repeating, start it.	580	If the timer is inactive and repeating, start it using the repeat value.
293		581
294	Otherwise do nothing.	582	Otherwise do nothing.
295		583
296	This behaviour is useful when you have a timeout for some IO	584	This behaviour is useful when you have a timeout for some IO
297	operation. You create a timer object with the same value for C<$after> and	585	operation. You create a timer object with the same value for C<$after> and
298	C<$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
299	on the timeout.	587	on the timeout.
300		588
		589	=back
		590
		591
		592	=head3 PERIODIC WATCHERS - to cron or not to cron?
		593
		594	=over 4
301		595
302	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback	596	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
303		597
304	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback	598	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		599
		600	=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
		601
		602	=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback)
305		603
306	Similar to EV::timer, but is not based on relative timeouts but on	604	Similar to EV::timer, but is not based on relative timeouts but on
307	absolute times. Apart from creating "simple" timers that trigger "at" the	605	absolute times. Apart from creating "simple" timers that trigger "at" the
308	specified time, it can also be used for non-drifting absolute timers and	606	specified time, it can also be used for non-drifting absolute timers and
309	more complex, cron-like, setups that are not adversely affected by time	607	more complex, cron-like, setups that are not adversely affected by time
…		…
319	This time simply fires at the wallclock time C<$at> and doesn't repeat. It	617	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
320	will not adjust when a time jump occurs, that is, if it is to be run	618	will not adjust when a time jump occurs, that is, if it is to be run
321	at January 1st 2011 then it will run when the system time reaches or	619	at January 1st 2011 then it will run when the system time reaches or
322	surpasses this time.	620	surpasses this time.
323		621
324	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)	622	=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
325		623
326	In this mode the watcher will always be scheduled to time out at the	624	In this mode the watcher will always be scheduled to time out at the
327	next C<$at + N * $interval> time (for some integer N) and then repeat,	625	next C<$at + N * $interval> time (for some integer N) and then repeat,
328	regardless of any time jumps.	626	regardless of any time jumps.
329		627
…		…
341	possible time where C<$time = $at (mod $interval)>, regardless of any time	639	possible time where C<$time = $at (mod $interval)>, regardless of any time
342	jumps.	640	jumps.
343		641
344	=item * manual reschedule mode ($reschedule_cb = coderef)	642	=item * manual reschedule mode ($reschedule_cb = coderef)
345		643
346	In this mode $interval and $at are both being ignored. Instead, each time	644	In this mode $interval and $at are both being ignored. Instead, each
347	the periodic watcher gets scheduled, the first callback ($reschedule_cb)	645	time the periodic watcher gets scheduled, the reschedule callback
348	will be called with the watcher as first, and the current time as second	646	($reschedule_cb) will be called with the watcher as first, and the current
349	argument.	647	time as second argument.
350		648
351	I<This callback MUST NOT stop or destroy this or any other periodic	649	I<This callback MUST NOT stop or destroy this or any other periodic
352	watcher, ever>. If you need to stop it, return 1e30 and stop it	650	watcher, ever, and MUST NOT call any event loop functions or methods>. If
353	afterwards.	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.
354		653
355	It must return the next time to trigger, based on the passed time value	654	It must return the next time to trigger, based on the passed time value
356	(that is, the lowest time value larger than to the second argument). It	655	(that is, the lowest time value larger than or equal to to the second
357	will usually be called just before the callback will be triggered, but	656	argument). It will usually be called just before the callback will be
358	might be called at other times, too.	657	triggered, but might be called at other times, too.
359		658
360	This can be used to create very complex timers, such as a timer that	659	This can be used to create very complex timers, such as a timer that
361	triggers on each midnight, local time (actually 24 hours after the last	660	triggers on each midnight, local time (actually 24 hours after the last
362	midnight, to keep the example simple. If you know a way to do it correctly	661	midnight, to keep the example simple. If you know a way to do it correctly
363	in about the same space (without requiring elaborate modules), drop me a	662	in about the same space (without requiring elaborate modules), drop me a
…		…
377		676
378	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.
379		678
380	=item $w->set ($at, $interval, $reschedule_cb)	679	=item $w->set ($at, $interval, $reschedule_cb)
381		680
382	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
383	any time.	682	any time.
384		683
385	=item $w->again	684	=item $w->again
386		685
387	Simply stops and starts the watcher again.	686	Simply stops and starts the watcher again.
388		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
389		698
390	=item $w = EV::signal $signal, $callback	699	=item $w = EV::signal $signal, $callback
391		700
392	=item $w = EV::signal_ns $signal, $callback	701	=item $w = EV::signal_ns $signal, $callback
393		702
394	Call the callback when $signal is received (the signal can be specified	703	Call the callback when $signal is received (the signal can be specified by
395	by number or by name, just as with kill or %SIG).	704	number or by name, just as with C<kill> or C<%SIG>).
396		705
397	EV will grab the signal for the process (the kernel only allows one	706	EV will grab the signal for the process (the kernel only allows one
398	component to receive a signal at a time) when you start a signal watcher,	707	component to receive a signal at a time) when you start a signal watcher,
399	and removes it again when you stop it. Perl does the same when you	708	and removes it again when you stop it. Perl does the same when you
400	add/remove callbacks to %SIG, so watch out.	709	add/remove callbacks to C<%SIG>, so watch out.
401		710
402	You can have as many signal watchers per signal as you want.	711	You can have as many signal watchers per signal as you want.
403		712
404	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	713	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
405		714
406	=item $w->set ($signal)	715	=item $w->set ($signal)
407		716
408	Reconfigures the watcher, see the constructor above for details. Can be at	717	Reconfigures the watcher, see the constructor above for details. Can be
409	any time.	718	called at any time.
410		719
411	=item $current_signum = $w->signal	720	=item $current_signum = $w->signal
412		721
413	=item $old_signum = $w->signal ($new_signal)	722	=item $old_signum = $w->signal ($new_signal)
414		723
415	Returns the previously set signal (always as a number not name) and	724	Returns the previously set signal (always as a number not name) and
416	optionally set a new one.	725	optionally set a new one.
417		726
		727	=back
418		728
		729
		730	=head3 CHILD WATCHERS - watch out for process status changes
		731
		732	=over 4
		733
419	=item $w = EV::child $pid, $callback	734	=item $w = EV::child $pid, $trace, $callback
420		735
421	=item $w = EV::child_ns $pid, $callback	736	=item $w = EV::child_ns $pid, $trace, $callback
		737
		738	=item $w = $loop->child ($pid, $trace, $callback)
		739
		740	=item $w = $loop->child_ns ($pid, $trace, $callback)
422		741
423	Call the callback when a status change for pid C<$pid> (or any pid	742	Call the callback when a status change for pid C<$pid> (or any pid
424	if C<$pid> is 0) has been received. More precisely: when the process	743	if C<$pid> is 0) has been received (a status change happens when the
		744	process terminates or is killed, or, when trace is true, additionally when
		745	it is stopped or continued). More precisely: when the process receives
425	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	746	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
426	changed/zombie children and call the callback.	747	changed/zombie children and call the callback.
427		748
428	You can access both status and pid by using the C<rstatus> and C<rpid>	749	It is valid (and fully supported) to install a child watcher after a child
429	methods on the watcher object.	750	has exited but before the event loop has started its next iteration (for
		751	example, first you C<fork>, then the new child process might exit, and
		752	only then do you install a child watcher in the parent for the new pid).
430		753
		754	You can access both exit (or tracing) status and pid by using the
		755	C<rstatus> and C<rpid> methods on the watcher object.
		756
431	You can have as many pid watchers per pid as you want.	757	You can have as many pid watchers per pid as you want, they will all be
		758	called.
432		759
433	The C<child_ns> variant doesn't start (activate) the newly created watcher.	760	The C<child_ns> variant doesn't start (activate) the newly created watcher.
434		761
435	=item $w->set ($pid)	762	=item $w->set ($pid, $trace)
436		763
437	Reconfigures the watcher, see the constructor above for details. Can be at	764	Reconfigures the watcher, see the constructor above for details. Can be called at
438	any time.	765	any time.
439		766
440	=item $current_pid = $w->pid	767	=item $current_pid = $w->pid
441
442	=item $old_pid = $w->pid ($new_pid)
443		768
444	Returns the previously set process id and optionally set a new one.	769	Returns the previously set process id and optionally set a new one.
445		770
446	=item $exit_status = $w->rstatus	771	=item $exit_status = $w->rstatus
447		772
…		…
451	=item $pid = $w->rpid	776	=item $pid = $w->rpid
452		777
453	Return the pid of the awaited child (useful when you have installed a	778	Return the pid of the awaited child (useful when you have installed a
454	watcher for all pids).	779	watcher for all pids).
455		780
		781	=back
		782
		783
		784	=head3 STAT WATCHERS - did the file attributes just change?
		785
		786	=over 4
		787
		788	=item $w = EV::stat $path, $interval, $callback
		789
		790	=item $w = EV::stat_ns $path, $interval, $callback
		791
		792	=item $w = $loop->stat ($path, $interval, $callback)
		793
		794	=item $w = $loop->stat_ns ($path, $interval, $callback)
		795
		796	Call the callback when a file status change has been detected on
		797	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		798	to "path does not exist" is a status change like any other.
		799
		800	The C<$interval> is a recommended polling interval for systems where
		801	OS-supported change notifications don't exist or are not supported. If
		802	you use C<0> then an unspecified default is used (which is highly
		803	recommended!), which is to be expected to be around five seconds usually.
		804
		805	This watcher type is not meant for massive numbers of stat watchers,
		806	as even with OS-supported change notifications, this can be
		807	resource-intensive.
		808
		809	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		810
		811	=item ... = $w->stat
		812
		813	This call is very similar to the perl C<stat> built-in: It stats (using
		814	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		815	well as EV's idea of the current stat values) to the values found.
		816
		817	In scalar context, a boolean is return indicating success or failure of
		818	the stat. In list context, the same 13-value list as with stat is returned
		819	(except that the blksize and blocks fields are not reliable).
		820
		821	In the case of an error, errno is set to C<ENOENT> (regardless of the
		822	actual error value) and the C<nlink> value is forced to zero (if the stat
		823	was successful then nlink is guaranteed to be non-zero).
		824
		825	See also the next two entries for more info.
		826
		827	=item ... = $w->attr
		828
		829	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		830	the values most recently detected by EV. See the next entry for more info.
		831
		832	=item ... = $w->prev
		833
		834	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		835	the previous set of values, before the change.
		836
		837	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		838	to the values found I<before> a change was detected, while C<< $w->attr >>
		839	returns the values found leading to the change detection. The difference (if any)
		840	between C<prev> and C<attr> is what triggered the callback.
		841
		842	If you did something to the filesystem object and do not want to trigger
		843	yet another change, you can call C<stat> to update EV's idea of what the
		844	current attributes are.
		845
		846	=item $w->set ($path, $interval)
		847
		848	Reconfigures the watcher, see the constructor above for details. Can be
		849	called at any time.
		850
		851	=item $current_path = $w->path
		852
		853	=item $old_path = $w->path ($new_path)
		854
		855	Returns the previously set path and optionally set a new one.
		856
		857	=item $current_interval = $w->interval
		858
		859	=item $old_interval = $w->interval ($new_interval)
		860
		861	Returns the previously set interval and optionally set a new one. Can be
		862	used to query the actual interval used.
		863
		864	=back
		865
		866
		867	=head3 IDLE WATCHERS - when you've got nothing better to do...
		868
		869	=over 4
456		870
457	=item $w = EV::idle $callback	871	=item $w = EV::idle $callback
458		872
459	=item $w = EV::idle_ns $callback	873	=item $w = EV::idle_ns $callback
460		874
461	Call the callback when there are no pending io, timer/periodic, signal or	875	=item $w = $loop->idle ($callback)
462	child events, i.e. when the process is idle.	876
		877	=item $w = $loop->idle_ns ($callback)
		878
		879	Call the callback when there are no other pending watchers of the same or
		880	higher priority (excluding check, prepare and other idle watchers of the
		881	same or lower priority, of course). They are called idle watchers because
		882	when the watcher is the highest priority pending event in the process, the
		883	process is considered to be idle at that priority.
		884
		885	If you want a watcher that is only ever called when I<no> other events are
		886	outstanding you have to set the priority to C<EV::MINPRI>.
463		887
464	The process will not block as long as any idle watchers are active, and	888	The process will not block as long as any idle watchers are active, and
465	they will be called repeatedly until stopped.	889	they will be called repeatedly until stopped.
466		890
		891	For example, if you have idle watchers at priority C<0> and C<1>, and
		892	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		893	and the I/O watcher will always run when ready. Only when the idle watcher
		894	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		895	pending with the C<0>-priority idle watcher be invoked.
		896
467	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	897	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
468		898
		899	=back
		900
		901
		902	=head3 PREPARE WATCHERS - customise your event loop!
		903
		904	=over 4
469		905
470	=item $w = EV::prepare $callback	906	=item $w = EV::prepare $callback
471		907
472	=item $w = EV::prepare_ns $callback	908	=item $w = EV::prepare_ns $callback
		909
		910	=item $w = $loop->prepare ($callback)
		911
		912	=item $w = $loop->prepare_ns ($callback)
473		913
474	Call the callback just before the process would block. You can still	914	Call the callback just before the process would block. You can still
475	create/modify any watchers at this point.	915	create/modify any watchers at this point.
476		916
477	See the EV::check watcher, below, for explanations and an example.	917	See the EV::check watcher, below, for explanations and an example.
478		918
479	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	919	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
480		920
		921	=back
		922
		923
		924	=head3 CHECK WATCHERS - customise your event loop even more!
		925
		926	=over 4
481		927
482	=item $w = EV::check $callback	928	=item $w = EV::check $callback
483		929
484	=item $w = EV::check_ns $callback	930	=item $w = EV::check_ns $callback
		931
		932	=item $w = $loop->check ($callback)
		933
		934	=item $w = $loop->check_ns ($callback)
485		935
486	Call the callback just after the process wakes up again (after it has	936	Call the callback just after the process wakes up again (after it has
487	gathered events), but before any other callbacks have been invoked.	937	gathered events), but before any other callbacks have been invoked.
488		938
489	This is used to integrate other event-based software into the EV	939	This is used to integrate other event-based software into the EV
…		…
497	# do nothing unless active	947	# do nothing unless active
498	$dispatcher->{_event_queue_h}	948	$dispatcher->{_event_queue_h}
499	or return;	949	or return;
500		950
501	# make the dispatcher handle any outstanding stuff	951	# make the dispatcher handle any outstanding stuff
		952	... not shown
502		953
503	# create an IO watcher for each and every socket	954	# create an I/O watcher for each and every socket
504	@snmp_watcher = (	955	@snmp_watcher = (
505	(map { EV::io $_, EV::READ, sub { } }	956	(map { EV::io $_, EV::READ, sub { } }
506	keys %{ $dispatcher->{_descriptors} }),	957	keys %{ $dispatcher->{_descriptors} }),
		958
		959	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		960	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		961	0, sub { },
507	);	962	);
508
509	# if there are any timeouts, also create a timer
510	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
511	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
512	};	963	};
513		964
514	The callbacks are irrelevant, the only purpose of those watchers is	965	The callbacks are irrelevant (and are not even being called), the
515	to wake up the process as soon as one of those events occurs (socket	966	only purpose of those watchers is to wake up the process as soon as
516	readable, or timer timed out). The corresponding EV::check watcher will then	967	one of those events occurs (socket readable, or timer timed out). The
517	clean up:	968	corresponding EV::check watcher will then clean up:
518		969
519	our $snmp_check = EV::check sub {	970	our $snmp_check = EV::check sub {
520	# destroy all watchers	971	# destroy all watchers
521	@snmp_watcher = ();	972	@snmp_watcher = ();
522		973
523	# make the dispatcher handle any new stuff	974	# make the dispatcher handle any new stuff
		975	... not shown
524	};	976	};
525		977
526	The callbacks of the created watchers will not be called as the watchers	978	The callbacks of the created watchers will not be called as the watchers
527	are destroyed before this cna happen (remember EV::check gets called	979	are destroyed before this can happen (remember EV::check gets called
528	first).	980	first).
529		981
530	The C<check_ns> variant doesn't start (activate) the newly created watcher.	982	The C<check_ns> variant doesn't start (activate) the newly created watcher.
531		983
532	=back	984	=back
533		985
		986
		987	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		988
		989	Fork watchers are called when a C<fork ()> was detected. The invocation
		990	is done before the event loop blocks next and before C<check> watchers
		991	are being called, and only in the child after the fork.
		992
		993	=over 4
		994
		995	=item $w = EV::fork $callback
		996
		997	=item $w = EV::fork_ns $callback
		998
		999	=item $w = $loop->fork ($callback)
		1000
		1001	=item $w = $loop->fork_ns ($callback)
		1002
		1003	Call the callback before the event loop is resumed in the child process
		1004	after a fork.
		1005
		1006	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		1007
		1008	=back
		1009
		1010
		1011	=head3 EMBED WATCHERS - when one backend isn't enough...
		1012
		1013	This is a rather advanced watcher type that lets you embed one event loop
		1014	into another (currently only IO events are supported in the embedded
		1015	loop, other types of watchers might be handled in a delayed or incorrect
		1016	fashion and must not be used).
		1017
		1018	See the libev documentation at
		1019	L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
		1020	(locally installed as F<EV::libev>) for more details.
		1021
		1022	In short, this watcher is most useful on BSD systems without working
		1023	kqueue to still be able to handle a large number of sockets:
		1024
		1025	my $socket_loop;
		1026
		1027	# check wether we use SELECT or POLL _and_ KQUEUE is supported
		1028	if (
		1029	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
		1030	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
		1031	) {
		1032	# use kqueue for sockets
		1033	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
		1034	}
		1035
		1036	# use the default loop otherwise
		1037	$socket_loop \|\|= EV::default_loop;
		1038
		1039	=over 4
		1040
		1041	=item $w = EV::embed $otherloop[, $callback]
		1042
		1043	=item $w = EV::embed_ns $otherloop[, $callback]
		1044
		1045	=item $w = $loop->embed ($otherloop[, $callback])
		1046
		1047	=item $w = $loop->embed_ns ($otherloop[, $callback])
		1048
		1049	Call the callback when the embedded event loop (C<$otherloop>) has any
		1050	I/O activity. The C<$callback> is optional: if it is missing, then the
		1051	embedded event loop will be managed automatically (which is recommended),
		1052	otherwise you have to invoke C<sweep> yourself.
		1053
		1054	The C<embed_ns> variant doesn't start (activate) the newly created watcher.
		1055
		1056	=back
		1057
		1058	=head3 ASYNC WATCHERS - how to wake up another event loop
		1059
		1060	Async watchers are provided by EV, but have little use in perl directly,
		1061	as perl neither supports threads running in parallel nor direct access to
		1062	signal handlers or other contexts where they could be of value.
		1063
		1064	It is, however, possible to use them from the XS level.
		1065
		1066	Please see the libev documentation for further details.
		1067
		1068	=over 4
		1069
		1070	=item $w = EV::async $callback
		1071
		1072	=item $w = EV::async_ns $callback
		1073
		1074	=item $w->send
		1075
		1076	=item $bool = $w->async_pending
		1077
		1078	=back
		1079
		1080
		1081	=head1 PERL SIGNALS
		1082
		1083	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		1084	with EV is as the same as any other C library: Perl-signals will only be
		1085	handled when Perl runs, which means your signal handler might be invoked
		1086	only the next time an event callback is invoked.
		1087
		1088	The solution is to use EV signal watchers (see C<EV::signal>), which will
		1089	ensure proper operations with regards to other event watchers.
		1090
		1091	If you cannot do this for whatever reason, you can also force a watcher
		1092	to be called on every event loop iteration by installing a C<EV::check>
		1093	watcher:
		1094
		1095	my $async_check = EV::check sub { };
		1096
		1097	This ensures that perl gets into control for a short time to handle any
		1098	pending signals, and also ensures (slightly) slower overall operation.
		1099
534	=head1 THREADS	1100	=head1 ITHREADS
535		1101
536	Threads are not supported by this in any way. Perl pseudo-threads is evil	1102	Ithreads are not supported by this module in any way. Perl pseudo-threads
537	stuff and must die.	1103	is evil stuff and must die. Real threads as provided by Coro are fully
		1104	supported (and enhanced support is available via L<Coro::EV>).
		1105
		1106	=head1 FORK
		1107
		1108	Most of the "improved" event delivering mechanisms of modern operating
		1109	systems have quite a few problems with fork(2) (to put it bluntly: it is
		1110	not supported and usually destructive). Libev makes it possible to work
		1111	around this by having a function that recreates the kernel state after
		1112	fork in the child.
		1113
		1114	On non-win32 platforms, this module requires the pthread_atfork
		1115	functionality to do this automatically for you. This function is quite
		1116	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		1117	negligible, because everything the function currently does is set a flag
		1118	that is checked only when the event loop gets used the next time, so when
		1119	you do fork but not use EV, the overhead is minimal.
		1120
		1121	On win32, there is no notion of fork so all this doesn't apply, of course.
538		1122
539	=cut	1123	=cut
540		1124
541	our $DIED = sub {	1125	our $DIED = sub {
542	warn "EV: error in callback (ignoring): $@";	1126	warn "EV: error in callback (ignoring): $@";
543	};	1127	};
544		1128
545	default_loop	1129	default_loop
546	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	1130	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
547
548	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
549		1131
550	1;	1132	1;
551		1133
552	=head1 SEE ALSO	1134	=head1 SEE ALSO
553		1135
554	L<EV::DNS>, L<EV::AnyEvent>.	1136	L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as
		1137	event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient
		1138	coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
		1139	event-loop agnostic and portable event driven programming.
555		1140
556	=head1 AUTHOR	1141	=head1 AUTHOR
557		1142
558	Marc Lehmann <schmorp@schmorp.de>	1143	Marc Lehmann <schmorp@schmorp.de>
559	http://home.schmorp.de/	1144	http://home.schmorp.de/
560		1145
561	=cut	1146	=cut
562		1147

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Comparing EV/EV.pm (file contents): Revision 1.32 by root, Thu Nov 8 17:02:10 2007 UTC vs. Revision 1.120 by root, Sun Jul 19 01:36:34 2009 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.32 by root, Thu Nov 8 17:02:10 2007 UTC vs.
Revision 1.120 by root, Sun Jul 19 01:36:34 2009 UTC