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

Comparing EV/EV.pm (file contents):
Revision 1.15 by root, Wed Oct 31 18:28:00 2007 UTC vs.
Revision 1.32 by root, Thu Nov 8 17:02:10 2007 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	EV - perl interface to libevent, monkey.org/~provos/libevent/	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		8
9	# TIMER	9	# TIMERS
10		10
11	my $w = EV::timer 2, 0, sub {	11	my $w = EV::timer 2, 0, sub {
12	warn "is called after 2s";	12	warn "is called after 2s";
13	};	13	};
14		14
16	warn "is called roughly every 2s (repeat = 1)";	16	warn "is called roughly every 2s (repeat = 1)";
17	};	17	};
18		18
19	undef $w; # destroy event watcher again	19	undef $w; # destroy event watcher again
20		20
21	my $w = EV::timer_abs 0, 60, sub {	21	my $w = EV::periodic 0, 60, 0, sub {
22	warn "is called every minute, on the minute, exactly";	22	warn "is called every minute, on the minute, exactly";
23	};	23	};
24		24
25	# IO	25	# IO
26		26
27	my $w = EV::io \*STDIN, EV::READ \| EV::PERSIST, sub {	27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $events) = @_; # all callbacks get the watcher object and event mask	28	my ($w, $revents) = @_; # all callbacks get the watcher object and event mask
29	if ($events & EV::TIMEOUT) {
30	warn "nothing received on stdin for 10 seconds, retrying";
31	} else {
32	warn "stdin is readable, you entered: ", <STDIN>;	29	warn "stdin is readable, you entered: ", <STDIN>;
33	}
34	};
35	$w->timeout (10);
36
37	my $w = EV::timed_io \*STDIN, EV::READ, 30, sub {
38	my ($w, $events) = @_;
39	if ($_[1] & EV::TIMEOUT) {
40	warn "nothing entered within 30 seconds, bye bye.\n";
41	$w->stop;
42	} else {
43	my $line = <STDIN>;
44	warn "you entered something, you again have 30 seconds.\n";
45	}
46	};	30	};
47		31
48	# SIGNALS	32	# SIGNALS
49		33
50	my $w = EV::signal 'QUIT', sub {	34	my $w = EV::signal 'QUIT', sub {
…		…
52	};	36	};
53		37
54	my $w = EV::signal 3, sub {	38	my $w = EV::signal 3, sub {
55	warn "sigquit received (this is GNU/Linux, right?)\n";	39	warn "sigquit received (this is GNU/Linux, right?)\n";
56	};	40	};
		41
		42	# CHILD/PID STATUS CHANGES
		43
		44	my $w = EV::child 666, sub {
		45	my ($w, $revents) = @_;
		46	# my $pid = $w->rpid;
		47	my $status = $w->rstatus;
		48	};
57		49
58	# MAINLOOP	50	# MAINLOOP
59	EV::dispatch; # loop as long as watchers are active	51	EV::loop; # loop until EV::loop_done is called
60	EV::loop; # the same thing
61	EV::loop EV::LOOP_ONCE; # block until some events could be handles	52	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
62	EV::loop EV::LOOP_NONBLOCK; # check and handle some events, but do not wait	53	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
63		54
64	=head1 DESCRIPTION	55	=head1 DESCRIPTION
65		56
66	This module provides an interface to libevent	57	This module provides an interface to libev
67	(L<http://monkey.org/~provos/libevent/>). You probably should acquaint	58	(L<http://software.schmorp.de/pkg/libev.html>).
68	yourself with its documentation and source code to be able to use this
69	module fully.
70
71	Please note thta this module disables the libevent EPOLL method by
72	default, see BUGS, below, if you need to enable it.
73		59
74	=cut	60	=cut
75		61
76	package EV;	62	package EV;
77		63
78	use strict;	64	use strict;
79		65
80	BEGIN {	66	BEGIN {
81	our $VERSION = '0.03';	67	our $VERSION = '0.6';
82	use XSLoader;	68	use XSLoader;
83	XSLoader::load "EV", $VERSION;	69	XSLoader::load "EV", $VERSION;
84	}	70	}
85		71
86	@EV::Io::ISA = "EV::Watcher";	72	@EV::Io::ISA =
87	@EV::Time::ISA = "EV::Watcher";
88	@EV::Timer::ISA = "EV::Time";	73	@EV::Timer::ISA =
89	@EV::Periodic::ISA = "EV::Time";	74	@EV::Periodic::ISA =
90	@EV::Signal::ISA = "EV::Watcher";	75	@EV::Signal::ISA =
91	@EV::Idle::ISA = "EV::Watcher";	76	@EV::Idle::ISA =
92	@EV::Prepare::ISA = "EV::Watcher";	77	@EV::Prepare::ISA =
		78	@EV::Check::ISA =
93	@EV::Check::ISA = "EV::Watcher";	79	@EV::Child::ISA = "EV::Watcher";
94		80
95	=head1 BASIC INTERFACE	81	=head1 BASIC INTERFACE
96		82
97	=over 4	83	=over 4
98
99	=item $EV::NPRI
100
101	How many priority levels are available.
102		84
103	=item $EV::DIED	85	=item $EV::DIED
104		86
105	Must contain a reference to a function that is called when a callback	87	Must contain a reference to a function that is called when a callback
106	throws an exception (with $@ containing thr error). The default prints an	88	throws an exception (with $@ containing thr error). The default prints an
107	informative message and continues.	89	informative message and continues.
108		90
109	If this callback throws an exception it will be silently ignored.	91	If this callback throws an exception it will be silently ignored.
110		92
		93	=item $time = EV::time
		94
		95	Returns the current time in (fractional) seconds since the epoch.
		96
111	=item $time = EV::now	97	=item $time = EV::now
112		98
113	Returns the time in (fractional) seconds since the epoch.	99	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
		101	usually faster then calling EV::time.
114		102
115	=item $version = EV::version
116
117	=item $method = EV::method	103	=item $method = EV::ev_method
118		104
119	Return version string and event polling method used.	105	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
		106	or EV::METHOD_EPOLL).
120		107
121	=item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT	108	=item EV::loop [$flags]
122		109
123	=item EV::loopexit $after	110	Begin checking for events and calling callbacks. It returns when a
		111	callback calls EV::loop_done.
124		112
125	Exit any active loop or dispatch after C<$after> seconds or immediately if	113	The $flags argument can be one of the following:
126	C<$after> is missing or zero.
127		114
128	=item EV::dispatch	115	0 as above
		116	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)
129		118
130	Same as C<EV::loop 0>.	119	=item EV::loop_done [$how]
131		120
132	=item EV::event $callback	121	When called with no arguments or an argument of 1, makes the innermost
		122	call to EV::loop return.
133		123
134	Creates a new event watcher waiting for nothing, calling the given callback.	124	When called with an agrument of 2, all calls to EV::loop will return as
		125	fast as possible.
135		126
		127	=back
		128
		129	=head2 WATCHER
		130
		131	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
		133	would create an EV::io watcher for that:
		134
		135	my $watcher = EV::io *STDIN, EV::READ, sub {
		136	my ($watcher, $revents) = @_;
		137	warn "yeah, STDIN should not be readable without blocking!\n"
		138	};
		139
		140	All watchers can be active (waiting for events) or inactive (paused). Only
		141	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
		143	events.
		144
		145	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
		147	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
		149	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
		150	uses EV::TIMEOUT).
		151
		152	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
		154	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
		155
		156	Please note that a watcher will automatically be stopped when the watcher
		157	object is destroyed, so you I<need> to keep the watcher objects returned by
		158	the constructors.
		159
		160	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,
		162	which means pending events get lost.
		163
		164	=head2 WATCHER TYPES
		165
		166	Now lets move to the existing watcher types and asociated methods.
		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
		173	=over 4
		174
		175	=item $w->start
		176
		177	Starts a watcher if it isn't active already. Does nothing to an already
		178	active watcher. By default, all watchers start out in the active state
		179	(see the description of the C<_ns> variants if you need stopped watchers).
		180
		181	=item $w->stop
		182
		183	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),
		185	regardless of wether the watcher was active or not.
		186
		187	=item $bool = $w->is_active
		188
		189	Returns true if the watcher is active, false otherwise.
		190
		191	=item $current_data = $w->data
		192
		193	=item $old_data = $w->data ($new_data)
		194
		195	Queries a freely usable data scalar on the watcher and optionally changes
		196	it. This is a way to associate custom data with a watcher:
		197
		198	my $w = EV::timer 60, 0, sub {
		199	warn $_[0]->data;
		200	};
		201	$w->data ("print me!");
		202
		203	=item $current_cb = $w->cb
		204
		205	=item $old_cb = $w->cb ($new_cb)
		206
		207	Queries the callback on the watcher and optionally changes it. You can do
		208	this at any time without the watcher restarting.
		209
		210	=item $current_priority = $w->priority
		211
		212	=item $old_priority = $w->priority ($new_priority)
		213
		214	Queries the priority on the watcher and optionally changes it. Pending
		215	watchers with higher priority will be invoked first. The valid range of
		216	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		217	-2). If the priority is outside this range it will automatically be
		218	normalised to the nearest valid priority.
		219
		220	The default priority of any newly-created weatcher is 0.
		221
		222	=item $w->trigger ($revents)
		223
		224	Call the callback now with the given event mask.
		225
		226
136	=item my $w = EV::io $fileno_or_fh, $eventmask, $callback	227	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
137		228
138	=item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	229	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
139		230
140	As long as the returned watcher object is alive, call the C<$callback>	231	As long as the returned watcher object is alive, call the C<$callback>
141	when the events specified in C<$eventmask> happen. Initially, the timeout	232	when the events specified in C<$eventmask>.
142	is disabled.
143		233
144	You can additionall set a timeout to occur on the watcher, but note that
145	this timeout will not be reset when you get an I/O event in the EV::PERSIST
146	case, and reaching a timeout will always stop the watcher even in the
147	EV::PERSIST case.
148
149	If you want a timeout to occur only after a specific time of inactivity, set
150	a repeating timeout and do NOT use EV::PERSIST.
151
152	Eventmask can be one or more of these constants ORed together:	234	The $eventmask can be one or more of these constants ORed together:
153		235
154	EV::READ wait until read() wouldn't block anymore	236	EV::READ wait until read() wouldn't block anymore
155	EV::WRITE wait until write() wouldn't block anymore	237	EV::WRITE wait until write() wouldn't block anymore
156	EV::PERSIST stay active after a (non-timeout) event occured
157		238
158	The C<io_ns> variant doesn't add/start the newly created watcher.	239	The C<io_ns> variant doesn't start (activate) the newly created watcher.
159		240
160	=item my $w = EV::timed_io $fileno_or_fh, $eventmask, $timeout, $callback	241	=item $w->set ($fileno_or_fh, $eventmask)
161		242
162	=item my $w = EV::timed_io_ns $fileno_or_fh, $eventmask, $timeout, $callback	243	Reconfigures the watcher, see the constructor above for details. Can be
		244	called at any time.
163		245
164	Same as C<io> and C<io_ns>, but also specifies a timeout (as if there was	246	=item $current_fh = $w->fh
165	a call to C<< $w->timeout ($timout, 1) >>. The persist flag is not allowed
166	and will automatically be cleared. The watcher will be restarted after each event.
167		247
168	If the timeout is zero or undef, no timeout will be set, and a normal	248	=item $old_fh = $w->fh ($new_fh)
169	watcher (with the persist flag set!) will be created.
170		249
171	This has the effect of timing out after the specified period of inactivity	250	Returns the previously set filehandle and optionally set a new one.
172	has happened.
173		251
174	Due to the design of libevent, this is also relatively inefficient, having	252	=item $current_eventmask = $w->events
175	one or two io watchers and a separate timeout watcher that you reset on
176	activity (by calling its C<start> method) is usually more efficient.
177		253
		254	=item $old_eventmask = $w->events ($new_eventmask)
		255
		256	Returns the previously set event mask and optionally set a new one.
		257
		258
178	=item my $w = EV::timer $after, $repeat, $callback	259	=item $w = EV::timer $after, $repeat, $callback
179		260
180	=item my $w = EV::timer_ns $after, $repeat, $callback	261	=item $w = EV::timer_ns $after, $repeat, $callback
181		262
182	Calls the callback after C<$after> seconds. If C<$repeat> is true, the	263	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,
183	timer will be restarted after the callback returns. This means that the	264	the timer will be restarted (with the $repeat value as $after) after the
184	callback would be called roughly every C<$after> seconds, prolonged by the	265	callback returns.
185	time the callback takes.
186		266
		267	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
		269	callback processing is not taken into account, so the timer will slowly
		270	drift. If that isn't acceptable, look at EV::periodic.
		271
		272	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
		274	clock, the timer will nevertheless run (roughly) the same time.
		275
187	The C<timer_ns> variant doesn't add/start the newly created watcher.	276	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
188		277
189	=item my $w = EV::timer_abs $at, $interval, $callback	278	=item $w->set ($after, $repeat)
190		279
191	=item my $w = EV::timer_abs_ns $at, $interval, $callback	280	Reconfigures the watcher, see the constructor above for details. Can be at
		281	any time.
192		282
193	Similar to EV::timer, but the time is given as an absolute point in time	283	=item $w->again
194	(C<$at>), plus an optional C<$interval>.
195		284
196	If the C<$interval> is zero, then the callback will be called at the time	285	Similar to the C<start> method, but has special semantics for repeating timers:
197	C<$at> if that is in the future, or as soon as possible if its in the
198	past. It will not automatically repeat.
199		286
200	If the C<$interval> is nonzero, then the watcher will always be scheduled	287	If the timer is active and repeating, reset the timeout to occur
201	to time out at the next C<$at + integer * $interval> time.	288	C<$repeat> seconds after now.
202		289
203	This can be used to schedule a callback to run at very regular intervals,	290	If the timer is active and non-repeating, it will be stopped.
204	as long as the processing time is less then the interval (otherwise	291
205	obviously events will be skipped).	292	If the timer is in active and repeating, start it.
		293
		294	Otherwise do nothing.
		295
		296	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<$after> and
		298	C<$repeat>, and then, in the read/write watcher, run the C<again> method
		299	on the timeout.
		300
		301
		302	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
		303
		304	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		305
		306	Similar to EV::timer, but is not based on relative timeouts but on
		307	absolute times. Apart from creating "simple" timers that trigger "at" the
		308	specified time, it can also be used for non-drifting absolute timers and
		309	more complex, cron-like, setups that are not adversely affected by time
		310	jumps (i.e. when the system clock is changed by explicit date -s or other
		311	means such as ntpd). It is also the most complex watcher type in EV.
		312
		313	It has three distinct "modes":
		314
		315	=over 4
		316
		317	=item * absolute timer ($interval = $reschedule_cb = 0)
		318
		319	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		320	will not adjust when a time jump occurs, that is, if it is to be run
		321	at January 1st 2011 then it will run when the system time reaches or
		322	surpasses this time.
		323
		324	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		325
		326	In this mode the watcher will always be scheduled to time out at the
		327	next C<$at + N * $interval> time (for some integer N) and then repeat,
		328	regardless of any time jumps.
		329
		330	This can be used to create timers that do not drift with respect to system
		331	time:
		332
		333	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		334
		335	That doesn't mean there will always be 3600 seconds in between triggers,
		336	but only that the the clalback will be called when the system time shows a
		337	full hour (UTC).
206		338
207	Another way to think about it (for the mathematically inclined) is that	339	Another way to think about it (for the mathematically inclined) is that
208	C<timer_abs> will try to tun the callback at the next possible time where	340	EV::periodic will try to run the callback in this mode at the next
209	C<$time = $at (mod $interval)>, regardless of any time jumps.	341	possible time where C<$time = $at (mod $interval)>, regardless of any time
		342	jumps.
210		343
		344	=item * manual reschedule mode ($reschedule_cb = coderef)
		345
		346	In this mode $interval and $at are both being ignored. Instead, each time
		347	the periodic watcher gets scheduled, the first callback ($reschedule_cb)
		348	will be called with the watcher as first, and the current time as second
		349	argument.
		350
		351	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
		353	afterwards.
		354
		355	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
		357	will usually be called just before the callback will be triggered, but
		358	might be called at other times, too.
		359
		360	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
		362	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
		364	note :):
		365
		366	my $daily = EV::periodic 0, 0, sub {
		367	my ($w, $now) = @_;
		368
		369	use Time::Local ();
		370	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		371	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		372	}, sub {
		373	print "it's midnight or likely shortly after, now\n";
		374	};
		375
		376	=back
		377
211	The C<timer_abs_ns> variant doesn't add/start the newly created watcher.	378	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
212		379
		380	=item $w->set ($at, $interval, $reschedule_cb)
		381
		382	Reconfigures the watcher, see the constructor above for details. Can be at
		383	any time.
		384
		385	=item $w->again
		386
		387	Simply stops and starts the watcher again.
		388
		389
213	=item my $w = EV::signal $signal, $callback	390	=item $w = EV::signal $signal, $callback
214		391
215	=item my $w = EV::signal_ns $signal, $callback	392	=item $w = EV::signal_ns $signal, $callback
216		393
217	Call the callback when $signal is received (the signal can be specified	394	Call the callback when $signal is received (the signal can be specified
218	by number or by name, just as with kill or %SIG). Signal watchers are	395	by number or by name, just as with kill or %SIG).
219	persistent no natter what.
220		396
221	EV will grab the signal for the process (the kernel only allows one	397	EV will grab the signal for the process (the kernel only allows one
222	component to receive signals) when you start a signal watcher, and	398	component to receive a signal at a time) when you start a signal watcher,
223	removes it again when you stop it. Pelr does the same when you add/remove	399	and removes it again when you stop it. Perl does the same when you
224	callbacks to %SIG, so watch out.	400	add/remove callbacks to %SIG, so watch out.
225		401
226	Unfortunately, only one handler can be registered per signal. Screw	402	You can have as many signal watchers per signal as you want.
227	libevent.
228		403
229	The C<signal_ns> variant doesn't add/start the newly created watcher.	404	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
		405
		406	=item $w->set ($signal)
		407
		408	Reconfigures the watcher, see the constructor above for details. Can be at
		409	any time.
		410
		411	=item $current_signum = $w->signal
		412
		413	=item $old_signum = $w->signal ($new_signal)
		414
		415	Returns the previously set signal (always as a number not name) and
		416	optionally set a new one.
		417
		418
		419	=item $w = EV::child $pid, $callback
		420
		421	=item $w = EV::child_ns $pid, $callback
		422
		423	Call the callback when a status change for pid C<$pid> (or any pid
		424	if C<$pid> is 0) has been received. More precisely: when the process
		425	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all
		426	changed/zombie children and call the callback.
		427
		428	You can access both status and pid by using the C<rstatus> and C<rpid>
		429	methods on the watcher object.
		430
		431	You can have as many pid watchers per pid as you want.
		432
		433	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		434
		435	=item $w->set ($pid)
		436
		437	Reconfigures the watcher, see the constructor above for details. Can be at
		438	any time.
		439
		440	=item $current_pid = $w->pid
		441
		442	=item $old_pid = $w->pid ($new_pid)
		443
		444	Returns the previously set process id and optionally set a new one.
		445
		446	=item $exit_status = $w->rstatus
		447
		448	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		449	in perlfunc).
		450
		451	=item $pid = $w->rpid
		452
		453	Return the pid of the awaited child (useful when you have installed a
		454	watcher for all pids).
		455
		456
		457	=item $w = EV::idle $callback
		458
		459	=item $w = EV::idle_ns $callback
		460
		461	Call the callback when there are no pending io, timer/periodic, signal or
		462	child events, i.e. when the process is idle.
		463
		464	The process will not block as long as any idle watchers are active, and
		465	they will be called repeatedly until stopped.
		466
		467	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
		468
		469
		470	=item $w = EV::prepare $callback
		471
		472	=item $w = EV::prepare_ns $callback
		473
		474	Call the callback just before the process would block. You can still
		475	create/modify any watchers at this point.
		476
		477	See the EV::check watcher, below, for explanations and an example.
		478
		479	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
		480
		481
		482	=item $w = EV::check $callback
		483
		484	=item $w = EV::check_ns $callback
		485
		486	Call the callback just after the process wakes up again (after it has
		487	gathered events), but before any other callbacks have been invoked.
		488
		489	This is used to integrate other event-based software into the EV
		490	mainloop: You register a prepare callback and in there, you create io and
		491	timer watchers as required by the other software. Here is a real-world
		492	example of integrating Net::SNMP (with some details left out):
		493
		494	our @snmp_watcher;
		495
		496	our $snmp_prepare = EV::prepare sub {
		497	# do nothing unless active
		498	$dispatcher->{_event_queue_h}
		499	or return;
		500
		501	# make the dispatcher handle any outstanding stuff
		502
		503	# create an IO watcher for each and every socket
		504	@snmp_watcher = (
		505	(map { EV::io $_, EV::READ, sub { } }
		506	keys %{ $dispatcher->{_descriptors} }),
		507	);
		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	};
		513
		514	The callbacks are irrelevant, the only purpose of those watchers is
		515	to wake up the process as soon as one of those events occurs (socket
		516	readable, or timer timed out). The corresponding EV::check watcher will then
		517	clean up:
		518
		519	our $snmp_check = EV::check sub {
		520	# destroy all watchers
		521	@snmp_watcher = ();
		522
		523	# make the dispatcher handle any new stuff
		524	};
		525
		526	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
		528	first).
		529
		530	The C<check_ns> variant doesn't start (activate) the newly created watcher.
230		531
231	=back	532	=back
232		533
233	=head1 THE EV::Event CLASS
234
235	All EV functions creating an event watcher (designated by C<my $w =>
236	above) support the following methods on the returned watcher object:
237
238	=over 4
239
240	=item $w->add ($timeout)
241
242	Stops and (re-)starts the event watcher, setting the optional timeout to
243	the given value, or clearing the timeout if none is given.
244
245	=item $w->start
246
247	Stops and (re-)starts the event watcher without touching the timeout.
248
249	=item $w->del
250
251	=item $w->stop
252
253	Stop the event watcher if it was started.
254
255	=item $current_callback = $w->cb
256
257	=item $old_callback = $w->cb ($new_callback)
258
259	Return the previously set callback and optionally set a new one.
260
261	=item $current_fh = $w->fh
262
263	=item $old_fh = $w->fh ($new_fh)
264
265	Returns the previously set filehandle and optionally set a new one (also
266	clears the EV::SIGNAL flag when setting a filehandle).
267
268	=item $current_signal = $w->signal
269
270	=item $old_signal = $w->signal ($new_signal)
271
272	Returns the previously set signal number and optionally set a new one (also sets
273	the EV::SIGNAL flag when setting a signal).
274
275	=item $current_eventmask = $w->events
276
277	=item $old_eventmask = $w->events ($new_eventmask)
278
279	Returns the previously set event mask and optionally set a new one.
280
281	=item $w->timeout ($after, $repeat)
282
283	Resets the timeout (see C<EV::timer> for details).
284
285	=item $w->timeout_abs ($at, $interval)
286
287	Resets the timeout (see C<EV::timer_abs> for details).
288
289	=item $w->priority_set ($priority)
290
291	Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI).
292
293	=back
294
295	=head1 THREADS	534	=head1 THREADS
296		535
297	Threads are not supported by this in any way. Perl pseudo-threads is evil	536	Threads are not supported by this in any way. Perl pseudo-threads is evil
298	and must die.	537	stuff and must die.
299
300	=head1 BUGS
301
302	Lots. Libevent itself isn't well tested and rather buggy, and this module
303	is quite new at the moment.
304
305	Please note that the epoll method is not, in general, reliable in programs
306	that use fork (even if no libveent calls are being made in the forked
307	process). If your program behaves erratically, try setting the environment
308	variable C<EVENT_NOEPOLL> first when running the program.
309
310	In general, if you fork, then you can only use the EV module in one of the
311	children.
312		538
313	=cut	539	=cut
314		540
315	our $DIED = sub {	541	our $DIED = sub {
316	warn "EV: error in callback (ignoring): $@";	542	warn "EV: error in callback (ignoring): $@";
317	};	543	};
318		544
319	init;	545	default_loop
		546	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
320		547
321	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];	548	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
322		549
323	1;	550	1;
324		551
325	=head1 SEE ALSO	552	=head1 SEE ALSO
326		553
327	L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>.
328	L<EV::AnyEvent>.	554	L<EV::DNS>, L<EV::AnyEvent>.
329		555
330	=head1 AUTHOR	556	=head1 AUTHOR
331		557
332	Marc Lehmann <schmorp@schmorp.de>	558	Marc Lehmann <schmorp@schmorp.de>
333	http://home.schmorp.de/	559	http://home.schmorp.de/

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Revision 1.32 by root, Thu Nov 8 17:02:10 2007 UTC