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

Comparing EV/EV.pm (file contents):
Revision 1.17 by root, Wed Oct 31 21:34:45 2007 UTC vs.
Revision 1.45 by root, Fri Nov 23 03:59:23 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
15	my $w = EV::timer 2, 1, sub {	15	my $w = EV::timer 2, 2, sub {
16	warn "is called roughly every 2s (repeat = 1)";	16	warn "is called roughly every 2s (repeat = 2)";
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, $revents) = @_; # all callbacks get the watcher object and event mask	28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29	if ($revents & 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, $revents) = @_;
39	if ($revents & 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 {
51	warn "sigquit received\n";	35	warn "sigquit received\n";
52	};	36	};
53		37
54	my $w = EV::signal 3, sub {
55	warn "sigquit received (this is GNU/Linux, right?)\n";
56	};
57
58	# CHILD/PID STATUS CHANGES	38	# CHILD/PID STATUS CHANGES
59		39
60	my $w = EV::child 666, sub {	40	my $w = EV::child 666, sub {
61	my ($w, $revents, $status) = @_;	41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
62	};	43	};
63		44
64	# MAINLOOP	45	# MAINLOOP
65	EV::dispatch; # loop as long as watchers are active	46	EV::loop; # loop until EV::unloop is called or all watchers stop
66	EV::loop; # the same thing
67	EV::loop EV::LOOP_ONESHOT; # block until some events could be handles	47	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
68	EV::loop EV::LOOP_NONBLOCK; # check and handle some events, but do not wait	48	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
69		49
70	=head1 DESCRIPTION	50	=head1 DESCRIPTION
71		51
72	This module provides an interface to libev	52	This module provides an interface to libev
73	(L<http://software.schmorp.de/pkg/libev.html>). You probably should	53	(L<http://software.schmorp.de/pkg/libev.html>).
74	acquaint yourself with its documentation and source code to be able to use
75	this module fully.
76		54
77	=cut	55	=cut
78		56
79	package EV;	57	package EV;
80		58
81	use strict;	59	use strict;
82		60
83	BEGIN {	61	BEGIN {
84	our $VERSION = '0.03';	62	our $VERSION = '1.2';
85	use XSLoader;	63	use XSLoader;
86	XSLoader::load "EV", $VERSION;	64	XSLoader::load "EV", $VERSION;
87	}	65	}
88		66
89	@EV::Io::ISA = "EV::Watcher";	67	@EV::Io::ISA =
90	@EV::Time::ISA = "EV::Watcher";
91	@EV::Timer::ISA = "EV::Time";	68	@EV::Timer::ISA =
92	@EV::Periodic::ISA = "EV::Time";	69	@EV::Periodic::ISA =
93	@EV::Signal::ISA = "EV::Watcher";	70	@EV::Signal::ISA =
94	@EV::Idle::ISA = "EV::Watcher";	71	@EV::Idle::ISA =
95	@EV::Prepare::ISA = "EV::Watcher";	72	@EV::Prepare::ISA =
96	@EV::Check::ISA = "EV::Watcher";	73	@EV::Check::ISA =
97	@EV::Child::ISA = "EV::Watcher";	74	@EV::Child::ISA = "EV::Watcher";
98		75
99	=head1 BASIC INTERFACE	76	=head1 BASIC INTERFACE
100		77
101	=over 4	78	=over 4
102
103	=item $EV::NPRI
104
105	How many priority levels are available.
106		79
107	=item $EV::DIED	80	=item $EV::DIED
108		81
109	Must contain a reference to a function that is called when a callback	82	Must contain a reference to a function that is called when a callback
110	throws an exception (with $@ containing thr error). The default prints an	83	throws an exception (with $@ containing thr error). The default prints an
111	informative message and continues.	84	informative message and continues.
112		85
113	If this callback throws an exception it will be silently ignored.	86	If this callback throws an exception it will be silently ignored.
114		87
		88	=item $time = EV::time
		89
		90	Returns the current time in (fractional) seconds since the epoch.
		91
115	=item $time = EV::now	92	=item $time = EV::now
116		93
117	Returns the time in (fractional) seconds since the epoch.	94	Returns the time the last event loop iteration has been started. This
118		95	is the time that (relative) timers are based on, and refering to it is
119	=item $version = EV::version	96	usually faster then calling EV::time.
120		97
121	=item $method = EV::method	98	=item $method = EV::method
122		99
123	Return version string and event polling method used.	100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
		101	or EV::METHOD_EPOLL).
124		102
125	=item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT	103	=item EV::loop [$flags]
126		104
127	=item EV::loopexit $after	105	Begin checking for events and calling callbacks. It returns when a
		106	callback calls EV::unloop.
128		107
129	Exit any active loop or dispatch after C<$after> seconds or immediately if	108	The $flags argument can be one of the following:
130	C<$after> is missing or zero.
131		109
132	=item EV::dispatch	110	0 as above
		111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
		112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
133		113
134	Same as C<EV::loop 0>.	114	=item EV::unloop [$how]
135		115
136	=item EV::event $callback	116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
		117	innermost call to EV::loop return.
137		118
138	Creates a new event watcher waiting for nothing, calling the given callback.	119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
		120	fast as possible.
139		121
		122	=back
		123
		124	=head2 WATCHER
		125
		126	A watcher is an object that gets created to record your interest in some
		127	event. For instance, if you want to wait for STDIN to become readable, you
		128	would create an EV::io watcher for that:
		129
		130	my $watcher = EV::io *STDIN, EV::READ, sub {
		131	my ($watcher, $revents) = @_;
		132	warn "yeah, STDIN should not be readable without blocking!\n"
		133	};
		134
		135	All watchers can be active (waiting for events) or inactive (paused). Only
		136	active watchers will have their callbacks invoked. All callbacks will be
		137	called with at least two arguments: the watcher and a bitmask of received
		138	events.
		139
		140	Each watcher type has its associated bit in revents, so you can use the
		141	same callback for multiple watchers. The event mask is named after the
		142	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
		143	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events
		144	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
		145	uses EV::TIMEOUT).
		146
		147	In the rare case where one wants to create a watcher but not start it at
		148	the same time, each constructor has a variant with a trailing C<_ns> in
		149	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
		150
		151	Please note that a watcher will automatically be stopped when the watcher
		152	object is destroyed, so you I<need> to keep the watcher objects returned by
		153	the constructors.
		154
		155	Also, all methods changing some aspect of a watcher (->set, ->priority,
		156	->fh and so on) automatically stop and start it again if it is active,
		157	which means pending events get lost.
		158
		159	=head2 WATCHER TYPES
		160
		161	Now lets move to the existing watcher types and asociated methods.
		162
		163	The following methods are available for all watchers. Then followes a
		164	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
		165	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
		166	any type-specific methods (if any).
		167
		168	=over 4
		169
		170	=item $w->start
		171
		172	Starts a watcher if it isn't active already. Does nothing to an already
		173	active watcher. By default, all watchers start out in the active state
		174	(see the description of the C<_ns> variants if you need stopped watchers).
		175
		176	=item $w->stop
		177
		178	Stop a watcher if it is active. Also clear any pending events (events that
		179	have been received but that didn't yet result in a callback invocation),
		180	regardless of wether the watcher was active or not.
		181
		182	=item $bool = $w->is_active
		183
		184	Returns true if the watcher is active, false otherwise.
		185
		186	=item $current_data = $w->data
		187
		188	=item $old_data = $w->data ($new_data)
		189
		190	Queries a freely usable data scalar on the watcher and optionally changes
		191	it. This is a way to associate custom data with a watcher:
		192
		193	my $w = EV::timer 60, 0, sub {
		194	warn $_[0]->data;
		195	};
		196	$w->data ("print me!");
		197
		198	=item $current_cb = $w->cb
		199
		200	=item $old_cb = $w->cb ($new_cb)
		201
		202	Queries the callback on the watcher and optionally changes it. You can do
		203	this at any time without the watcher restarting.
		204
		205	=item $current_priority = $w->priority
		206
		207	=item $old_priority = $w->priority ($new_priority)
		208
		209	Queries the priority on the watcher and optionally changes it. Pending
		210	watchers with higher priority will be invoked first. The valid range of
		211	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		212	-2). If the priority is outside this range it will automatically be
		213	normalised to the nearest valid priority.
		214
		215	The default priority of any newly-created weatcher is 0.
		216
		217	=item $w->trigger ($revents)
		218
		219	Call the callback now with the given event mask.
		220
		221
140	=item my $w = EV::io $fileno_or_fh, $eventmask, $callback	222	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
141		223
142	=item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	224	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
143		225
144	As long as the returned watcher object is alive, call the C<$callback>	226	As long as the returned watcher object is alive, call the C<$callback>
145	when the events specified in C<$eventmask> happen. Initially, the timeout	227	when the events specified in C<$eventmask>.
146	is disabled.
147		228
148	You can additionall set a timeout to occur on the watcher, but note that
149	this timeout will not be reset when you get an I/O event in the EV::PERSIST
150	case, and reaching a timeout will always stop the watcher even in the
151	EV::PERSIST case.
152
153	If you want a timeout to occur only after a specific time of inactivity, set
154	a repeating timeout and do NOT use EV::PERSIST.
155
156	Eventmask can be one or more of these constants ORed together:	229	The $eventmask can be one or more of these constants ORed together:
157		230
158	EV::READ wait until read() wouldn't block anymore	231	EV::READ wait until read() wouldn't block anymore
159	EV::WRITE wait until write() wouldn't block anymore	232	EV::WRITE wait until write() wouldn't block anymore
160	EV::PERSIST stay active after a (non-timeout) event occured
161		233
162	The C<io_ns> variant doesn't add/start the newly created watcher.	234	The C<io_ns> variant doesn't start (activate) the newly created watcher.
163		235
164	=item my $w = EV::timed_io $fileno_or_fh, $eventmask, $timeout, $callback	236	=item $w->set ($fileno_or_fh, $eventmask)
165		237
166	=item my $w = EV::timed_io_ns $fileno_or_fh, $eventmask, $timeout, $callback	238	Reconfigures the watcher, see the constructor above for details. Can be
		239	called at any time.
167		240
168	Same as C<io> and C<io_ns>, but also specifies a timeout (as if there was	241	=item $current_fh = $w->fh
169	a call to C<< $w->timeout ($timout, 1) >>. The persist flag is not allowed
170	and will automatically be cleared. The watcher will be restarted after each event.
171		242
172	If the timeout is zero or undef, no timeout will be set, and a normal	243	=item $old_fh = $w->fh ($new_fh)
173	watcher (with the persist flag set!) will be created.
174		244
175	This has the effect of timing out after the specified period of inactivity	245	Returns the previously set filehandle and optionally set a new one.
176	has happened.
177		246
178	Due to the design of libevent, this is also relatively inefficient, having	247	=item $current_eventmask = $w->events
179	one or two io watchers and a separate timeout watcher that you reset on
180	activity (by calling its C<start> method) is usually more efficient.
181		248
		249	=item $old_eventmask = $w->events ($new_eventmask)
		250
		251	Returns the previously set event mask and optionally set a new one.
		252
		253
182	=item my $w = EV::timer $after, $repeat, $callback	254	=item $w = EV::timer $after, $repeat, $callback
183		255
184	=item my $w = EV::timer_ns $after, $repeat, $callback	256	=item $w = EV::timer_ns $after, $repeat, $callback
185		257
186	Calls the callback after C<$after> seconds. If C<$repeat> is true, the	258	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,
187	timer will be restarted after the callback returns. This means that the	259	the timer will be restarted (with the $repeat value as $after) after the
188	callback would be called roughly every C<$after> seconds, prolonged by the	260	callback returns.
189	time the callback takes.
190		261
		262	This means that the callback would be called roughly after C<$after>
		263	seconds, and then every C<$repeat> seconds. The timer does his best not
		264	to drift, but it will not invoke the timer more often then once per event
		265	loop iteration, and might drift in other cases. If that isn't acceptable,
		266	look at EV::periodic, which can provide long-term stable timers.
		267
		268	The timer is based on a monotonic clock, that is, if somebody is sitting
		269	in front of the machine while the timer is running and changes the system
		270	clock, the timer will nevertheless run (roughly) the same time.
		271
191	The C<timer_ns> variant doesn't add/start the newly created watcher.	272	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
192		273
193	=item my $w = EV::timer_abs $at, $interval, $callback	274	=item $w->set ($after, $repeat)
194		275
195	=item my $w = EV::timer_abs_ns $at, $interval, $callback	276	Reconfigures the watcher, see the constructor above for details. Can be at
		277	any time.
196		278
197	Similar to EV::timer, but the time is given as an absolute point in time	279	=item $w->again
198	(C<$at>), plus an optional C<$interval>.
199		280
200	If the C<$interval> is zero, then the callback will be called at the time	281	Similar to the C<start> method, but has special semantics for repeating timers:
201	C<$at> if that is in the future, or as soon as possible if its in the
202	past. It will not automatically repeat.
203		282
204	If the C<$interval> is nonzero, then the watcher will always be scheduled	283	If the timer is active and non-repeating, it will be stopped.
205	to time out at the next C<$at + integer * $interval> time.
206		284
207	This can be used to schedule a callback to run at very regular intervals,	285	If the timer is active and repeating, reset the timeout to occur
208	as long as the processing time is less then the interval (otherwise	286	C<$repeat> seconds after now.
209	obviously events will be skipped).	287
		288	If the timer is inactive and repeating, start it using the repeat value.
		289
		290	Otherwise do nothing.
		291
		292	This behaviour is useful when you have a timeout for some IO
		293	operation. You create a timer object with the same value for C<$after> and
		294	C<$repeat>, and then, in the read/write watcher, run the C<again> method
		295	on the timeout.
		296
		297
		298	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
		299
		300	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		301
		302	Similar to EV::timer, but is not based on relative timeouts but on
		303	absolute times. Apart from creating "simple" timers that trigger "at" the
		304	specified time, it can also be used for non-drifting absolute timers and
		305	more complex, cron-like, setups that are not adversely affected by time
		306	jumps (i.e. when the system clock is changed by explicit date -s or other
		307	means such as ntpd). It is also the most complex watcher type in EV.
		308
		309	It has three distinct "modes":
		310
		311	=over 4
		312
		313	=item * absolute timer ($interval = $reschedule_cb = 0)
		314
		315	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		316	will not adjust when a time jump occurs, that is, if it is to be run
		317	at January 1st 2011 then it will run when the system time reaches or
		318	surpasses this time.
		319
		320	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		321
		322	In this mode the watcher will always be scheduled to time out at the
		323	next C<$at + N * $interval> time (for some integer N) and then repeat,
		324	regardless of any time jumps.
		325
		326	This can be used to create timers that do not drift with respect to system
		327	time:
		328
		329	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		330
		331	That doesn't mean there will always be 3600 seconds in between triggers,
		332	but only that the the clalback will be called when the system time shows a
		333	full hour (UTC).
210		334
211	Another way to think about it (for the mathematically inclined) is that	335	Another way to think about it (for the mathematically inclined) is that
212	C<timer_abs> will try to tun the callback at the next possible time where	336	EV::periodic will try to run the callback in this mode at the next
213	C<$time = $at (mod $interval)>, regardless of any time jumps.	337	possible time where C<$time = $at (mod $interval)>, regardless of any time
		338	jumps.
214		339
		340	=item * manual reschedule mode ($reschedule_cb = coderef)
		341
		342	In this mode $interval and $at are both being ignored. Instead, each
		343	time the periodic watcher gets scheduled, the reschedule callback
		344	($reschedule_cb) will be called with the watcher as first, and the current
		345	time as second argument.
		346
		347	I<This callback MUST NOT stop or destroy this or any other periodic
		348	watcher, ever>. If you need to stop it, return 1e30 and stop it
		349	afterwards.
		350
		351	It must return the next time to trigger, based on the passed time value
		352	(that is, the lowest time value larger than to the second argument). It
		353	will usually be called just before the callback will be triggered, but
		354	might be called at other times, too.
		355
		356	This can be used to create very complex timers, such as a timer that
		357	triggers on each midnight, local time (actually 24 hours after the last
		358	midnight, to keep the example simple. If you know a way to do it correctly
		359	in about the same space (without requiring elaborate modules), drop me a
		360	note :):
		361
		362	my $daily = EV::periodic 0, 0, sub {
		363	my ($w, $now) = @_;
		364
		365	use Time::Local ();
		366	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		367	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		368	}, sub {
		369	print "it's midnight or likely shortly after, now\n";
		370	};
		371
		372	=back
		373
215	The C<timer_abs_ns> variant doesn't add/start the newly created watcher.	374	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
216		375
		376	=item $w->set ($at, $interval, $reschedule_cb)
		377
		378	Reconfigures the watcher, see the constructor above for details. Can be at
		379	any time.
		380
		381	=item $w->again
		382
		383	Simply stops and starts the watcher again.
		384
		385
217	=item my $w = EV::signal $signal, $callback	386	=item $w = EV::signal $signal, $callback
218		387
219	=item my $w = EV::signal_ns $signal, $callback	388	=item $w = EV::signal_ns $signal, $callback
220		389
221	Call the callback when $signal is received (the signal can be specified	390	Call the callback when $signal is received (the signal can be specified
222	by number or by name, just as with kill or %SIG). Signal watchers are	391	by number or by name, just as with kill or %SIG).
223	persistent no natter what.
224		392
225	EV will grab the signal for the process (the kernel only allows one	393	EV will grab the signal for the process (the kernel only allows one
226	component to receive signals) when you start a signal watcher, and	394	component to receive a signal at a time) when you start a signal watcher,
227	removes it again when you stop it. Pelr does the same when you add/remove	395	and removes it again when you stop it. Perl does the same when you
228	callbacks to %SIG, so watch out.	396	add/remove callbacks to %SIG, so watch out.
229		397
230	Unfortunately, only one handler can be registered per signal. Screw	398	You can have as many signal watchers per signal as you want.
231	libevent.
232		399
233	The C<signal_ns> variant doesn't add/start the newly created watcher.	400	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
		401
		402	=item $w->set ($signal)
		403
		404	Reconfigures the watcher, see the constructor above for details. Can be at
		405	any time.
		406
		407	=item $current_signum = $w->signal
		408
		409	=item $old_signum = $w->signal ($new_signal)
		410
		411	Returns the previously set signal (always as a number not name) and
		412	optionally set a new one.
		413
		414
		415	=item $w = EV::child $pid, $callback
		416
		417	=item $w = EV::child_ns $pid, $callback
		418
		419	Call the callback when a status change for pid C<$pid> (or any pid
		420	if C<$pid> is 0) has been received. More precisely: when the process
		421	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all
		422	changed/zombie children and call the callback.
		423
		424	You can access both status and pid by using the C<rstatus> and C<rpid>
		425	methods on the watcher object.
		426
		427	You can have as many pid watchers per pid as you want.
		428
		429	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		430
		431	=item $w->set ($pid)
		432
		433	Reconfigures the watcher, see the constructor above for details. Can be at
		434	any time.
		435
		436	=item $current_pid = $w->pid
		437
		438	=item $old_pid = $w->pid ($new_pid)
		439
		440	Returns the previously set process id and optionally set a new one.
		441
		442	=item $exit_status = $w->rstatus
		443
		444	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		445	in perlfunc).
		446
		447	=item $pid = $w->rpid
		448
		449	Return the pid of the awaited child (useful when you have installed a
		450	watcher for all pids).
		451
		452
		453	=item $w = EV::idle $callback
		454
		455	=item $w = EV::idle_ns $callback
		456
		457	Call the callback when there are no pending io, timer/periodic, signal or
		458	child events, i.e. when the process is idle.
		459
		460	The process will not block as long as any idle watchers are active, and
		461	they will be called repeatedly until stopped.
		462
		463	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
		464
		465
		466	=item $w = EV::prepare $callback
		467
		468	=item $w = EV::prepare_ns $callback
		469
		470	Call the callback just before the process would block. You can still
		471	create/modify any watchers at this point.
		472
		473	See the EV::check watcher, below, for explanations and an example.
		474
		475	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
		476
		477
		478	=item $w = EV::check $callback
		479
		480	=item $w = EV::check_ns $callback
		481
		482	Call the callback just after the process wakes up again (after it has
		483	gathered events), but before any other callbacks have been invoked.
		484
		485	This is used to integrate other event-based software into the EV
		486	mainloop: You register a prepare callback and in there, you create io and
		487	timer watchers as required by the other software. Here is a real-world
		488	example of integrating Net::SNMP (with some details left out):
		489
		490	our @snmp_watcher;
		491
		492	our $snmp_prepare = EV::prepare sub {
		493	# do nothing unless active
		494	$dispatcher->{_event_queue_h}
		495	or return;
		496
		497	# make the dispatcher handle any outstanding stuff
		498	... not shown
		499
		500	# create an IO watcher for each and every socket
		501	@snmp_watcher = (
		502	(map { EV::io $_, EV::READ, sub { } }
		503	keys %{ $dispatcher->{_descriptors} }),
		504
		505	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		506	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		507	0, sub { },
		508	);
		509	};
		510
		511	The callbacks are irrelevant (and are not even being called), the
		512	only purpose of those watchers is to wake up the process as soon as
		513	one of those events occurs (socket readable, or timer timed out). The
		514	corresponding EV::check watcher will then clean up:
		515
		516	our $snmp_check = EV::check sub {
		517	# destroy all watchers
		518	@snmp_watcher = ();
		519
		520	# make the dispatcher handle any new stuff
		521	... not shown
		522	};
		523
		524	The callbacks of the created watchers will not be called as the watchers
		525	are destroyed before this cna happen (remember EV::check gets called
		526	first).
		527
		528	The C<check_ns> variant doesn't start (activate) the newly created watcher.
234		529
235	=back	530	=back
236		531
237	=head1 THE EV::Event CLASS
238
239	All EV functions creating an event watcher (designated by C<my $w =>
240	above) support the following methods on the returned watcher object:
241
242	=over 4
243
244	=item $w->add ($timeout)
245
246	Stops and (re-)starts the event watcher, setting the optional timeout to
247	the given value, or clearing the timeout if none is given.
248
249	=item $w->start
250
251	Stops and (re-)starts the event watcher without touching the timeout.
252
253	=item $w->del
254
255	=item $w->stop
256
257	Stop the event watcher if it was started.
258
259	=item $current_callback = $w->cb
260
261	=item $old_callback = $w->cb ($new_callback)
262
263	Return the previously set callback and optionally set a new one.
264
265	=item $current_fh = $w->fh
266
267	=item $old_fh = $w->fh ($new_fh)
268
269	Returns the previously set filehandle and optionally set a new one (also
270	clears the EV::SIGNAL flag when setting a filehandle).
271
272	=item $current_signal = $w->signal
273
274	=item $old_signal = $w->signal ($new_signal)
275
276	Returns the previously set signal number and optionally set a new one (also sets
277	the EV::SIGNAL flag when setting a signal).
278
279	=item $current_eventmask = $w->events
280
281	=item $old_eventmask = $w->events ($new_eventmask)
282
283	Returns the previously set event mask and optionally set a new one.
284
285	=item $w->timeout ($after, $repeat)
286
287	Resets the timeout (see C<EV::timer> for details).
288
289	=item $w->timeout_abs ($at, $interval)
290
291	Resets the timeout (see C<EV::timer_abs> for details).
292
293	=item $w->priority_set ($priority)
294
295	Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI).
296
297	=back
298
299	=head1 THREADS	532	=head1 THREADS
300		533
301	Threads are not supported by this in any way. Perl pseudo-threads is evil	534	Threads are not supported by this module in any way. Perl pseudo-threads
302	and must die.	535	is evil stuff and must die.
303
304	=head1 BUGS
305
306	Lots. Libevent itself isn't well tested and rather buggy, and this module
307	is quite new at the moment.
308
309	Please note that the epoll method is not, in general, reliable in programs
310	that use fork (even if no libveent calls are being made in the forked
311	process). If your program behaves erratically, try setting the environment
312	variable C<EVENT_NOEPOLL> first when running the program.
313
314	In general, if you fork, then you can only use the EV module in one of the
315	children.
316		536
317	=cut	537	=cut
318		538
319	our $DIED = sub {	539	our $DIED = sub {
320	warn "EV: error in callback (ignoring): $@";	540	warn "EV: error in callback (ignoring): $@";
321	};	541	};
322		542
323	init;	543	default_loop
324		544	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
325	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
326		545
327	1;	546	1;
328		547
329	=head1 SEE ALSO	548	=head1 SEE ALSO
330		549
331	L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>.	550	L<EV::DNS>.
332	L<EV::AnyEvent>.
333		551
334	=head1 AUTHOR	552	=head1 AUTHOR
335		553
336	Marc Lehmann <schmorp@schmorp.de>	554	Marc Lehmann <schmorp@schmorp.de>
337	http://home.schmorp.de/	555	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.17 by root, Wed Oct 31 21:34:45 2007 UTC vs. Revision 1.45 by root, Fri Nov 23 03:59:23 2007 UTC

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Revision 1.17 by root, Wed Oct 31 21:34:45 2007 UTC vs.
Revision 1.45 by root, Fri Nov 23 03:59:23 2007 UTC