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Revision 1.226 by root, Mon Jul 6 23:32:49 2009 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event loops.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub {	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		14
		15	# one-shot or repeating timers
		16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		18
		19	print AnyEvent->now; # prints current event loop time
		20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		21
		22	# POSIX signal
		23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		24
		25	# child process exit
		26	my $w = AnyEvent->child (pid => $pid, cb => sub {
		27	my ($pid, $status) = @_;
12	...	28	...
13	});	29	});
14		30
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	31	# called when event loop idle (if applicable)
16	...	32	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		33
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		35	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->send; # wake up current and all future wait's	37	# use a condvar in callback mode:
		38	$w->cb (sub { $_[0]->recv });
		39
		40	=head1 INTRODUCTION/TUTORIAL
		41
		42	This manpage is mainly a reference manual. If you are interested
		43	in a tutorial or some gentle introduction, have a look at the
		44	L<AnyEvent::Intro> manpage.
22		45
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		47
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	49	nowadays. So what is different about AnyEvent?
27		50
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	51	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	52	policy> and AnyEvent is I<small and efficient>.
30		53
31	First and foremost, I<AnyEvent is not an event model> itself, it only	54	First and foremost, I<AnyEvent is not an event model> itself, it only
32	interfaces to whatever event model the main program happens to use in a	55	interfaces to whatever event model the main program happens to use, in a
33	pragmatic way. For event models and certain classes of immortals alike,	56	pragmatic way. For event models and certain classes of immortals alike,
34	the statement "there can only be one" is a bitter reality: In general,	57	the statement "there can only be one" is a bitter reality: In general,
35	only one event loop can be active at the same time in a process. AnyEvent	58	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	59	cannot change this, but it can hide the differences between those event
		60	loops.
37		61
38	The goal of AnyEvent is to offer module authors the ability to do event	62	The goal of AnyEvent is to offer module authors the ability to do event
39	programming (waiting for I/O or timer events) without subscribing to a	63	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	64	religion, a way of living, and most importantly: without forcing your
41	module users into the same thing by forcing them to use the same event	65	module users into the same thing by forcing them to use the same event
42	model you use.	66	model you use.
43		67
44	For modules like POE or IO::Async (which is a total misnomer as it is	68	For modules like POE or IO::Async (which is a total misnomer as it is
45	actually doing all I/O I<synchronously>...), using them in your module is	69	actually doing all I/O I<synchronously>...), using them in your module is
46	like joining a cult: After you joined, you are dependent on them and you	70	like joining a cult: After you joined, you are dependent on them and you
47	cannot use anything else, as it is simply incompatible to everything that	71	cannot use anything else, as they are simply incompatible to everything
48	isn't itself. What's worse, all the potential users of your module are	72	that isn't them. What's worse, all the potential users of your
49	I<also> forced to use the same event loop you use.	73	module are I<also> forced to use the same event loop you use.
50		74
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if	77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	78	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	79	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	80	event models it supports (including stuff like IO::Async, as long as those
57	as those use one of the supported event loops. It is trivial to add new	81	use one of the supported event loops. It is trivial to add new event loops
58	event loops to AnyEvent, too, so it is future-proof).	82	to AnyEvent, too, so it is future-proof).
59		83
60	In addition to being free of having to use I<the one and only true event	84	In addition to being free of having to use I<the one and only true event
61	model>, AnyEvent also is free of bloat and policy: with POE or similar	85	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enourmous amount of code and strict rules you have to	86	modules, you get an enormous amount of code and strict rules you have to
63	follow. AnyEvent, on the other hand, is lean and up to the point, by only	87	follow. AnyEvent, on the other hand, is lean and up to the point, by only
64	offering the functionality that is necessary, in as thin as a wrapper as	88	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	89	technically possible.
66		90
		91	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		92	of useful functionality, such as an asynchronous DNS resolver, 100%
		93	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		94	such as Windows) and lots of real-world knowledge and workarounds for
		95	platform bugs and differences.
		96
67	Of course, if you want lots of policy (this can arguably be somewhat	97	Now, if you I<do want> lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	98	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	99	model, you should I<not> use this module.
70		100
71	=head1 DESCRIPTION	101	=head1 DESCRIPTION
72		102
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	132	starts using it, all bets are off. Maybe you should tell their authors to
103	use AnyEvent so their modules work together with others seamlessly...	133	use AnyEvent so their modules work together with others seamlessly...
104		134
105	The pure-perl implementation of AnyEvent is called	135	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	137	explicitly and enjoy the high availability of that event loop :)
108		138
109	=head1 WATCHERS	139	=head1 WATCHERS
110		140
111	AnyEvent has the central concept of a I<watcher>, which is an object that	141	AnyEvent has the central concept of a I<watcher>, which is an object that
112	stores relevant data for each kind of event you are waiting for, such as	142	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	143	the callback to call, the file handle to watch, etc.
114		144
115	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	146	creating a watcher it will immediately "watch" for events and invoke the
117	callback when the event occurs (of course, only when the event model	147	callback when the event occurs (of course, only when the event model
118	is in control).	148	is in control).
119		149
		150	Note that B<callbacks must not permanently change global variables>
		151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		152	callbacks must not C<die> >>. The former is good programming practise in
		153	Perl and the latter stems from the fact that exception handling differs
		154	widely between event loops.
		155
120	To disable the watcher you have to destroy it (e.g. by setting the	156	To disable the watcher you have to destroy it (e.g. by setting the
121	variable you store it in to C<undef> or otherwise deleting all references	157	variable you store it in to C<undef> or otherwise deleting all references
122	to it).	158	to it).
123		159
124	All watchers are created by calling a method on the C<AnyEvent> class.	160	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
126	Many watchers either are used with "recursion" (repeating timers for	162	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	163	example), or need to refer to their watcher object in other ways.
128		164
129	An any way to achieve that is this pattern:	165	An any way to achieve that is this pattern:
130		166
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	168	# you can use $w here, for example to undef it
133	undef $w;	169	undef $w;
134	});	170	});
135		171
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	172	Note that C<my $w; $w => combination. This is necessary because in Perl,
137	my variables are only visible after the statement in which they are	173	my variables are only visible after the statement in which they are
138	declared.	174	declared.
139		175
140	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
141		177
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
144		180
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		182	for events (AnyEvent might or might not keep a reference to this file
		183	handle). Note that only file handles pointing to things for which
		184	non-blocking operation makes sense are allowed. This includes sockets,
		185	most character devices, pipes, fifos and so on, but not for example files
		186	or block devices.
		187
146	for events. C<poll> must be a string that is either C<r> or C<w>,	188	C<poll> must be a string that is either C<r> or C<w>, which creates a
147	which creates a watcher waiting for "r"eadable or "w"ritable events,	189	watcher waiting for "r"eadable or "w"ritable events, respectively.
		190
148	respectively. C<cb> is the callback to invoke each time the file handle	191	C<cb> is the callback to invoke each time the file handle becomes ready.
149	becomes ready.
150		192
151	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
154		196
…		…
158		200
159	Some event loops issue spurious readyness notifications, so you should	201	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	202	always use non-blocking calls when reading/writing from/to your file
161	handles.	203	handles.
162		204
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	205	Example: wait for readability of STDIN, then read a line and disable the
		206	watcher.
		207
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	208	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	209	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	210	warn "read: $input\n";
169	undef $w;	211	undef $w;
170	});	212	});
…		…
180		222
181	Although the callback might get passed parameters, their value and	223	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	224	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	225	callbacks cannot use arguments passed to time watcher callbacks.
184		226
185	The timer callback will be invoked at most once: if you want a repeating	227	The callback will normally be invoked once only. If you specify another
186	timer you have to create a new watcher (this is a limitation by both Tk	228	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	229	callback will be invoked regularly at that interval (in fractional
		230	seconds) after the first invocation. If C<interval> is specified with a
		231	false value, then it is treated as if it were missing.
188		232
189	Example:	233	The callback will be rescheduled before invoking the callback, but no
		234	attempt is done to avoid timer drift in most backends, so the interval is
		235	only approximate.
190		236
191	# fire an event after 7.7 seconds	237	Example: fire an event after 7.7 seconds.
		238
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	239	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	240	warn "timeout\n";
194	});	241	});
195		242
196	# to cancel the timer:	243	# to cancel the timer:
197	undef $w;	244	undef $w;
198		245
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	246	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		247
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	248	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		249	warn "timeout\n";
207	};	250	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		251
212	=head3 TIMING ISSUES	252	=head3 TIMING ISSUES
213		253
214	There are two ways to handle timers: based on real time (relative, "fire	254	There are two ways to handle timers: based on real time (relative, "fire
215	in 10 seconds") and based on wallclock time (absolute, "fire at 12	255	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	267	timers.
228		268
229	AnyEvent always prefers relative timers, if available, matching the	269	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	270	AnyEvent API.
231		271
		272	AnyEvent has two additional methods that return the "current time":
		273
		274	=over 4
		275
		276	=item AnyEvent->time
		277
		278	This returns the "current wallclock time" as a fractional number of
		279	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		280	return, and the result is guaranteed to be compatible with those).
		281
		282	It progresses independently of any event loop processing, i.e. each call
		283	will check the system clock, which usually gets updated frequently.
		284
		285	=item AnyEvent->now
		286
		287	This also returns the "current wallclock time", but unlike C<time>, above,
		288	this value might change only once per event loop iteration, depending on
		289	the event loop (most return the same time as C<time>, above). This is the
		290	time that AnyEvent's timers get scheduled against.
		291
		292	I<In almost all cases (in all cases if you don't care), this is the
		293	function to call when you want to know the current time.>
		294
		295	This function is also often faster then C<< AnyEvent->time >>, and
		296	thus the preferred method if you want some timestamp (for example,
		297	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		298
		299	The rest of this section is only of relevance if you try to be very exact
		300	with your timing, you can skip it without bad conscience.
		301
		302	For a practical example of when these times differ, consider L<Event::Lib>
		303	and L<EV> and the following set-up:
		304
		305	The event loop is running and has just invoked one of your callback at
		306	time=500 (assume no other callbacks delay processing). In your callback,
		307	you wait a second by executing C<sleep 1> (blocking the process for a
		308	second) and then (at time=501) you create a relative timer that fires
		309	after three seconds.
		310
		311	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		312	both return C<501>, because that is the current time, and the timer will
		313	be scheduled to fire at time=504 (C<501> + C<3>).
		314
		315	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		316	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		317	last event processing phase started. With L<EV>, your timer gets scheduled
		318	to run at time=503 (C<500> + C<3>).
		319
		320	In one sense, L<Event::Lib> is more exact, as it uses the current time
		321	regardless of any delays introduced by event processing. However, most
		322	callbacks do not expect large delays in processing, so this causes a
		323	higher drift (and a lot more system calls to get the current time).
		324
		325	In another sense, L<EV> is more exact, as your timer will be scheduled at
		326	the same time, regardless of how long event processing actually took.
		327
		328	In either case, if you care (and in most cases, you don't), then you
		329	can get whatever behaviour you want with any event loop, by taking the
		330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		331	account.
		332
		333	=item AnyEvent->now_update
		334
		335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		336	the current time for each loop iteration (see the discussion of L<<
		337	AnyEvent->now >>, above).
		338
		339	When a callback runs for a long time (or when the process sleeps), then
		340	this "current" time will differ substantially from the real time, which
		341	might affect timers and time-outs.
		342
		343	When this is the case, you can call this method, which will update the
		344	event loop's idea of "current time".
		345
		346	Note that updating the time I<might> cause some events to be handled.
		347
		348	=back
		349
232	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
233		351
234	You can watch for signals using a signal watcher, C<signal> is the signal	352	You can watch for signals using a signal watcher, C<signal> is the signal
235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	354	callback to be invoked whenever a signal occurs.
237		355
238	Although the callback might get passed parameters, their value and	356	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	357	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	358	callbacks cannot use arguments passed to signal watcher callbacks.
241		359
242	Multiple signal occurances can be clumped together into one callback	360	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	361	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	362	that it might take a while until the signal gets handled by the process,
245	but it is guarenteed not to interrupt any other callbacks.	363	but it is guaranteed not to interrupt any other callbacks.
246		364
247	The main advantage of using these watchers is that you can share a signal	365	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	366	between multiple watchers.
249		367
250	This watcher might use C<%SIG>, so programs overwriting those signals	368	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
257	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
258		376
259	You can also watch on a child process exit and catch its exit status.	377	You can also watch on a child process exit and catch its exit status.
260		378
261	The child process is specified by the C<pid> argument (if set to C<0>, it	379	The child process is specified by the C<pid> argument (if set to C<0>, it
262	watches for any child process exit). The watcher will trigger as often	380	watches for any child process exit). The watcher will triggered only when
263	as status change for the child are received. This works by installing a	381	the child process has finished and an exit status is available, not on
264	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
265	and exit status (as returned by waitpid), so unlike other watcher types,	383
266	you I<can> rely on child watcher callback arguments.	384	The callback will be called with the pid and exit status (as returned by
		385	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		386	callback arguments.
		387
		388	This watcher type works by installing a signal handler for C<SIGCHLD>,
		389	and since it cannot be shared, nothing else should use SIGCHLD or reap
		390	random child processes (waiting for specific child processes, e.g. inside
		391	C<system>, is just fine).
267		392
268	There is a slight catch to child watchers, however: you usually start them	393	There is a slight catch to child watchers, however: you usually start them
269	I<after> the child process was created, and this means the process could	394	I<after> the child process was created, and this means the process could
270	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
271		396
272	Not all event models handle this correctly (POE doesn't), but even for	397	Not all event models handle this correctly (neither POE nor IO::Async do,
		398	see their AnyEvent::Impl manpages for details), but even for event models
273	event models that I<do> handle this correctly, they usually need to be	399	that I<do> handle this correctly, they usually need to be loaded before
274	loaded before the process exits (i.e. before you fork in the first place).	400	the process exits (i.e. before you fork in the first place). AnyEvent's
		401	pure perl event loop handles all cases correctly regardless of when you
		402	start the watcher.
275		403
276	This means you cannot create a child watcher as the very first thing in an	404	This means you cannot create a child watcher as the very first
277	AnyEvent program, you I<have> to create at least one watcher before you	405	thing in an AnyEvent program, you I<have> to create at least one
278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	406	watcher before you C<fork> the child (alternatively, you can call
		407	C<AnyEvent::detect>).
279		408
280	Example: fork a process and wait for it	409	Example: fork a process and wait for it
281		410
282	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
283		412
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	413	my $pid = fork or exit 5;
287		414
288	my $w = AnyEvent->child (	415	my $w = AnyEvent->child (
289	pid => $pid,	416	pid => $pid,
290	cb => sub {	417	cb => sub {
291	my ($pid, $status) = @_;	418	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	419	warn "pid $pid exited with status $status";
293	$done->send;	420	$done->send;
294	},	421	},
295	);	422	);
296		423
297	# do something else, then wait for process exit	424	# do something else, then wait for process exit
298	$done->wait;	425	$done->recv;
		426
		427	=head2 IDLE WATCHERS
		428
		429	Sometimes there is a need to do something, but it is not so important
		430	to do it instantly, but only when there is nothing better to do. This
		431	"nothing better to do" is usually defined to be "no other events need
		432	attention by the event loop".
		433
		434	Idle watchers ideally get invoked when the event loop has nothing
		435	better to do, just before it would block the process to wait for new
		436	events. Instead of blocking, the idle watcher is invoked.
		437
		438	Most event loops unfortunately do not really support idle watchers (only
		439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		440	will simply call the callback "from time to time".
		441
		442	Example: read lines from STDIN, but only process them when the
		443	program is otherwise idle:
		444
		445	my @lines; # read data
		446	my $idle_w;
		447	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		448	push @lines, scalar <STDIN>;
		449
		450	# start an idle watcher, if not already done
		451	$idle_w ||= AnyEvent->idle (cb => sub {
		452	# handle only one line, when there are lines left
		453	if (my $line = shift @lines) {
		454	print "handled when idle: $line";
		455	} else {
		456	# otherwise disable the idle watcher again
		457	undef $idle_w;
		458	}
		459	});
		460	});
299		461
300	=head2 CONDITION VARIABLES	462	=head2 CONDITION VARIABLES
301		463
302	If you are familiar with some event loops you will know that all of them	464	If you are familiar with some event loops you will know that all of them
303	require you to run some blocking "loop", "run" or similar function that	465	require you to run some blocking "loop", "run" or similar function that
…		…
309	The instrument to do that is called a "condition variable", so called	471	The instrument to do that is called a "condition variable", so called
310	because they represent a condition that must become true.	472	because they represent a condition that must become true.
311		473
312	Condition variables can be created by calling the C<< AnyEvent->condvar	474	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	475	>> method, usually without arguments. The only argument pair allowed is
		476
314	C<cb>, which specifies a callback to be called when the condition variable	477	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	478	becomes true, with the condition variable as the first argument (but not
		479	the results).
316		480
317	After creation, the conditon variable is "false" until it becomes "true"	481	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	482	by calling the C<send> method (or calling the condition variable as if it
		483	were a callback, read about the caveats in the description for the C<<
		484	->send >> method).
319		485
320	Condition variables are similar to callbacks, except that you can	486	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	487	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	488	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	489	another way to call them is transactions - each condition variable can be
324	used to represent a transaction, which finishes at some point and delivers	490	used to represent a transaction, which finishes at some point and delivers
325	a result.	491	a result.
326		492
327	Condition variables are very useful to signal that something has finished,	493	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	494	for example, if you write a module that does asynchronous http requests,
329	then a condition variable would be the ideal candidate to signal the	495	then a condition variable would be the ideal candidate to signal the
330	availability of results. The user can either act when the callback is	496	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	497	called or can synchronously C<< ->recv >> for the results.
332		498
333	You can also use them to simulate traditional event loops - for example,	499	You can also use them to simulate traditional event loops - for example,
334	you can block your main program until an event occurs - for example, you	500	you can block your main program until an event occurs - for example, you
335	could C<< ->wait >> in your main program until the user clicks the Quit	501	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->send >> the "quit" event.	502	button of your app, which would C<< ->send >> the "quit" event.
337		503
338	Note that condition variables recurse into the event loop - if you have	504	Note that condition variables recurse into the event loop - if you have
339	two pieces of code that call C<< ->wait >> in a round-robbin fashion, you	505	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
340	lose. Therefore, condition variables are good to export to your caller, but	506	lose. Therefore, condition variables are good to export to your caller, but
341	you should avoid making a blocking wait yourself, at least in callbacks,	507	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	508	as this asks for trouble.
343		509
344	Condition variables are represented by hash refs in perl, and the keys	510	Condition variables are represented by hash refs in perl, and the keys
…		…
349		515
350	There are two "sides" to a condition variable - the "producer side" which	516	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	517	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	518	for the send to occur.
353		519
354	Example:	520	Example: wait for a timer.
355		521
356	# wait till the result is ready	522	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	523	my $result_ready = AnyEvent->condvar;
358		524
359	# do something such as adding a timer	525	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	531	cb => sub { $result_ready->send },
366	);	532	);
367		533
368	# this "blocks" (while handling events) till the callback	534	# this "blocks" (while handling events) till the callback
369	# calls send	535	# calls send
370	$result_ready->wait;	536	$result_ready->recv;
		537
		538	Example: wait for a timer, but take advantage of the fact that
		539	condition variables are also code references.
		540
		541	my $done = AnyEvent->condvar;
		542	my $delay = AnyEvent->timer (after => 5, cb => $done);
		543	$done->recv;
		544
		545	Example: Imagine an API that returns a condvar and doesn't support
		546	callbacks. This is how you make a synchronous call, for example from
		547	the main program:
		548
		549	use AnyEvent::CouchDB;
		550
		551	...
		552
		553	my @info = $couchdb->info->recv;
		554
		555	And this is how you would just ste a callback to be called whenever the
		556	results are available:
		557
		558	$couchdb->info->cb (sub {
		559	my @info = $_[0]->recv;
		560	});
371		561
372	=head3 METHODS FOR PRODUCERS	562	=head3 METHODS FOR PRODUCERS
373		563
374	These methods should only be used by the producing side, i.e. the	564	These methods should only be used by the producing side, i.e. the
375	code/module that eventually sends the signal. Note that it is also	565	code/module that eventually sends the signal. Note that it is also
…		…
378		568
379	=over 4	569	=over 4
380		570
381	=item $cv->send (...)	571	=item $cv->send (...)
382		572
383	Flag the condition as ready - a running C<< ->wait >> and all further	573	Flag the condition as ready - a running C<< ->recv >> and all further
384	calls to C<wait> will (eventually) return after this method has been	574	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	575	called. If nobody is waiting the send will be remembered.
386		576
387	If a callback has been set on the condition variable, it is called	577	If a callback has been set on the condition variable, it is called
388	immediately from within send.	578	immediately from within send.
389		579
390	Any arguments passed to the C<send> call will be returned by all	580	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	581	future C<< ->recv >> calls.
		582
		583	Condition variables are overloaded so one can call them directly
		584	(as a code reference). Calling them directly is the same as calling
		585	C<send>. Note, however, that many C-based event loops do not handle
		586	overloading, so as tempting as it may be, passing a condition variable
		587	instead of a callback does not work. Both the pure perl and EV loops
		588	support overloading, however, as well as all functions that use perl to
		589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		590	example).
392		591
393	=item $cv->croak ($error)	592	=item $cv->croak ($error)
394		593
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	594	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	595	C<Carp::croak> with the given error message/object/scalar.
397		596
398	This can be used to signal any errors to the condition variable	597	This can be used to signal any errors to the condition variable
399	user/consumer.	598	user/consumer.
400		599
…		…
410	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
411	>>, the (last) callback passed to C<begin> will be executed. That callback	610	>>, the (last) callback passed to C<begin> will be executed. That callback
412	is I<supposed> to call C<< ->send >>, but that is not required. If no	611	is I<supposed> to call C<< ->send >>, but that is not required. If no
413	callback was set, C<send> will be called without any arguments.	612	callback was set, C<send> will be called without any arguments.
414		613
415	Let's clarify this with the ping example:	614	You can think of C<< $cv->send >> giving you an OR condition (one call
		615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		617
		618	Let's start with a simple example: you have two I/O watchers (for example,
		619	STDOUT and STDERR for a program), and you want to wait for both streams to
		620	close before activating a condvar:
		621
		622	my $cv = AnyEvent->condvar;
		623
		624	$cv->begin; # first watcher
		625	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		626	defined sysread $fh1, my $buf, 4096
		627	or $cv->end;
		628	});
		629
		630	$cv->begin; # second watcher
		631	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		632	defined sysread $fh2, my $buf, 4096
		633	or $cv->end;
		634	});
		635
		636	$cv->recv;
		637
		638	This works because for every event source (EOF on file handle), there is
		639	one call to C<begin>, so the condvar waits for all calls to C<end> before
		640	sending.
		641
		642	The ping example mentioned above is slightly more complicated, as the
		643	there are results to be passwd back, and the number of tasks that are
		644	begung can potentially be zero:
416		645
417	my $cv = AnyEvent->condvar;	646	my $cv = AnyEvent->condvar;
418		647
419	my %result;	648	my %result;
420	$cv->begin (sub { $cv->send (\%result) });	649	$cv->begin (sub { $cv->send (\%result) });
…		…
440	loop, which serves two important purposes: first, it sets the callback	669	loop, which serves two important purposes: first, it sets the callback
441	to be called once the counter reaches C<0>, and second, it ensures that	670	to be called once the counter reaches C<0>, and second, it ensures that
442	C<send> is called even when C<no> hosts are being pinged (the loop	671	C<send> is called even when C<no> hosts are being pinged (the loop
443	doesn't execute once).	672	doesn't execute once).
444		673
445	This is the general pattern when you "fan out" into multiple subrequests:	674	This is the general pattern when you "fan out" into multiple (but
446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
447	is called at least once, and then, for each subrequest you start, call	676	the callback and ensure C<end> is called at least once, and then, for each
448	C<begin> and for eahc subrequest you finish, call C<end>.	677	subrequest you start, call C<begin> and for each subrequest you finish,
		678	call C<end>.
449		679
450	=back	680	=back
451		681
452	=head3 METHODS FOR CONSUMERS	682	=head3 METHODS FOR CONSUMERS
453		683
454	These methods should only be used by the consuming side, i.e. the	684	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	685	code awaits the condition.
456		686
457	=over 4	687	=over 4
458		688
459	=item $cv->wait	689	=item $cv->recv
460		690
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	692	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	693	normally.
464		694
…		…
475	(programs might want to do that to stay interactive), so I<if you are	705	(programs might want to do that to stay interactive), so I<if you are
476	using this from a module, never require a blocking wait>, but let the	706	using this from a module, never require a blocking wait>, but let the
477	caller decide whether the call will block or not (for example, by coupling	707	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	708	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	709	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	710	while still supporting blocking waits if the caller so desires).
481		711
482	Another reason I<never> to C<< ->wait >> in a module is that you cannot	712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->wait >>'s in parallel, as that would require	713	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	715	can supply.
486		716
487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in	717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
488	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe	718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489	versions and also integrates coroutines into AnyEvent, making blocking	719	versions and also integrates coroutines into AnyEvent, making blocking
490	C<< ->wait >> calls perfectly safe as long as they are done from another	720	C<< ->recv >> calls perfectly safe as long as they are done from another
491	coroutine (one that doesn't run the event loop).	721	coroutine (one that doesn't run the event loop).
492		722
493	You can ensure that C<< -wait >> never blocks by setting a callback and	723	You can ensure that C<< -recv >> never blocks by setting a callback and
494	only calling C<< ->wait >> from within that callback (or at a later	724	only calling C<< ->recv >> from within that callback (or at a later
495	time). This will work even when the event loop does not support blocking	725	time). This will work even when the event loop does not support blocking
496	waits otherwise.	726	waits otherwise.
497		727
498	=item $bool = $cv->ready	728	=item $bool = $cv->ready
499		729
500	Returns true when the condition is "true", i.e. whether C<send> or	730	Returns true when the condition is "true", i.e. whether C<send> or
501	C<croak> have been called.	731	C<croak> have been called.
502		732
503	=item $cb = $cv->cb ([new callback])	733	=item $cb = $cv->cb ($cb->($cv))
504		734
505	This is a mutator function that returns the callback set and optionally	735	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	736	replaces it before doing so.
507		737
508	The callback will be called when the condition becomes "true", i.e. when	738	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<wait> inside the callback	739	C<send> or C<croak> are called, with the only argument being the condition
510	or at any later time is guaranteed not to block.	740	variable itself. Calling C<recv> inside the callback or at any later time
		741	is guaranteed not to block.
511		742
512	=back	743	=back
513		744
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	745	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		746
…		…
532	AnyEvent::Impl::Tk based on Tk, very bad choice.	763	AnyEvent::Impl::Tk based on Tk, very bad choice.
533	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
534	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
535	AnyEvent::Impl::POE based on POE, not generic enough for full support.	766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
536		767
		768	# warning, support for IO::Async is only partial, as it is too broken
		769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
		770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
		771
537	There is no support for WxWidgets, as WxWidgets has no support for	772	There is no support for WxWidgets, as WxWidgets has no support for
538	watching file handles. However, you can use WxWidgets through the	773	watching file handles. However, you can use WxWidgets through the
539	POE Adaptor, as POE has a Wx backend that simply polls 20 times per	774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
540	second, which was considered to be too horrible to even consider for	775	second, which was considered to be too horrible to even consider for
541	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using	776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
…		…
582	Be careful when you create watchers in the module body - AnyEvent will	817	Be careful when you create watchers in the module body - AnyEvent will
583	decide which event module to use as soon as the first method is called, so	818	decide which event module to use as soon as the first method is called, so
584	by calling AnyEvent in your module body you force the user of your module	819	by calling AnyEvent in your module body you force the user of your module
585	to load the event module first.	820	to load the event module first.
586		821
587	Never call C<< ->wait >> on a condition variable unless you I<know> that	822	Never call C<< ->recv >> on a condition variable unless you I<know> that
588	the C<< ->send >> method has been called on it already. This is	823	the C<< ->send >> method has been called on it already. This is
589	because it will stall the whole program, and the whole point of using	824	because it will stall the whole program, and the whole point of using
590	events is to stay interactive.	825	events is to stay interactive.
591		826
592	It is fine, however, to call C<< ->wait >> when the user of your module	827	It is fine, however, to call C<< ->recv >> when the user of your module
593	requests it (i.e. if you create a http request object ad have a method	828	requests it (i.e. if you create a http request object ad have a method
594	called C<results> that returns the results, it should call C<< ->wait >>	829	called C<results> that returns the results, it should call C<< ->recv >>
595	freely, as the user of your module knows what she is doing. always).	830	freely, as the user of your module knows what she is doing. always).
596		831
597	=head1 WHAT TO DO IN THE MAIN PROGRAM	832	=head1 WHAT TO DO IN THE MAIN PROGRAM
598		833
599	There will always be a single main program - the only place that should	834	There will always be a single main program - the only place that should
…		…
601		836
602	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	837	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
603	do anything special (it does not need to be event-based) and let AnyEvent	838	do anything special (it does not need to be event-based) and let AnyEvent
604	decide which implementation to chose if some module relies on it.	839	decide which implementation to chose if some module relies on it.
605		840
606	If the main program relies on a specific event model. For example, in	841	If the main program relies on a specific event model - for example, in
607	Gtk2 programs you have to rely on the Glib module. You should load the	842	Gtk2 programs you have to rely on the Glib module - you should load the
608	event module before loading AnyEvent or any module that uses it: generally	843	event module before loading AnyEvent or any module that uses it: generally
609	speaking, you should load it as early as possible. The reason is that	844	speaking, you should load it as early as possible. The reason is that
610	modules might create watchers when they are loaded, and AnyEvent will	845	modules might create watchers when they are loaded, and AnyEvent will
611	decide on the event model to use as soon as it creates watchers, and it	846	decide on the event model to use as soon as it creates watchers, and it
612	might chose the wrong one unless you load the correct one yourself.	847	might chose the wrong one unless you load the correct one yourself.
613		848
614	You can chose to use a rather inefficient pure-perl implementation by	849	You can chose to use a pure-perl implementation by loading the
615	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	850	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616	behaviour everywhere, but letting AnyEvent chose is generally better.	851	everywhere, but letting AnyEvent chose the model is generally better.
		852
		853	=head2 MAINLOOP EMULATION
		854
		855	Sometimes (often for short test scripts, or even standalone programs who
		856	only want to use AnyEvent), you do not want to run a specific event loop.
		857
		858	In that case, you can use a condition variable like this:
		859
		860	AnyEvent->condvar->recv;
		861
		862	This has the effect of entering the event loop and looping forever.
		863
		864	Note that usually your program has some exit condition, in which case
		865	it is better to use the "traditional" approach of storing a condition
		866	variable somewhere, waiting for it, and sending it when the program should
		867	exit cleanly.
		868
617		869
618	=head1 OTHER MODULES	870	=head1 OTHER MODULES
619		871
620	The following is a non-exhaustive list of additional modules that use	872	The following is a non-exhaustive list of additional modules that use
621	AnyEvent and can therefore be mixed easily with other AnyEvent modules	873	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
627	=item L<AnyEvent::Util>	879	=item L<AnyEvent::Util>
628		880
629	Contains various utility functions that replace often-used but blocking	881	Contains various utility functions that replace often-used but blocking
630	functions such as C<inet_aton> by event-/callback-based versions.	882	functions such as C<inet_aton> by event-/callback-based versions.
631		883
		884	=item L<AnyEvent::Socket>
		885
		886	Provides various utility functions for (internet protocol) sockets,
		887	addresses and name resolution. Also functions to create non-blocking tcp
		888	connections or tcp servers, with IPv6 and SRV record support and more.
		889
632	=item L<AnyEvent::Handle>	890	=item L<AnyEvent::Handle>
633		891
634	Provide read and write buffers and manages watchers for reads and writes.	892	Provide read and write buffers, manages watchers for reads and writes,
		893	supports raw and formatted I/O, I/O queued and fully transparent and
		894	non-blocking SSL/TLS.
635		895
636	=item L<AnyEvent::Socket>	896	=item L<AnyEvent::DNS>
637		897
638	Provides a means to do non-blocking connects, accepts etc.	898	Provides rich asynchronous DNS resolver capabilities.
		899
		900	=item L<AnyEvent::HTTP>
		901
		902	A simple-to-use HTTP library that is capable of making a lot of concurrent
		903	HTTP requests.
639		904
640	=item L<AnyEvent::HTTPD>	905	=item L<AnyEvent::HTTPD>
641		906
642	Provides a simple web application server framework.	907	Provides a simple web application server framework.
643		908
644	=item L<AnyEvent::DNS>
645
646	Provides asynchronous DNS resolver capabilities, beyond what
647	L<AnyEvent::Util> offers.
648
649	=item L<AnyEvent::FastPing>	909	=item L<AnyEvent::FastPing>
650		910
651	The fastest ping in the west.	911	The fastest ping in the west.
652		912
		913	=item L<AnyEvent::DBI>
		914
		915	Executes L<DBI> requests asynchronously in a proxy process.
		916
		917	=item L<AnyEvent::AIO>
		918
		919	Truly asynchronous I/O, should be in the toolbox of every event
		920	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		921	together.
		922
		923	=item L<AnyEvent::BDB>
		924
		925	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		926	L<BDB> and AnyEvent together.
		927
		928	=item L<AnyEvent::GPSD>
		929
		930	A non-blocking interface to gpsd, a daemon delivering GPS information.
		931
		932	=item L<AnyEvent::IGS>
		933
		934	A non-blocking interface to the Internet Go Server protocol (used by
		935	L<App::IGS>).
		936
653	=item L<Net::IRC3>	937	=item L<AnyEvent::IRC>
654		938
655	AnyEvent based IRC client module family.	939	AnyEvent based IRC client module family (replacing the older Net::IRC3).
656		940
657	=item L<Net::XMPP2>	941	=item L<Net::XMPP2>
658		942
659	AnyEvent based XMPP (Jabber protocol) module family.	943	AnyEvent based XMPP (Jabber protocol) module family.
660		944
…		…
673		957
674	=item L<IO::Lambda>	958	=item L<IO::Lambda>
675		959
676	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	960	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
677		961
678	=item L<IO::AIO>
679
680	Truly asynchronous I/O, should be in the toolbox of every event
681	programmer. Can be trivially made to use AnyEvent.
682
683	=item L<BDB>
684
685	Truly asynchronous Berkeley DB access. Can be trivially made to use
686	AnyEvent.
687
688	=back	962	=back
689		963
690	=cut	964	=cut
691		965
692	package AnyEvent;	966	package AnyEvent;
693		967
694	no warnings;	968	no warnings;
695	use strict;	969	use strict qw(vars subs);
696		970
697	use Carp;	971	use Carp;
698		972
699	our $VERSION = '3.4';	973	our $VERSION = 4.8;
700	our $MODEL;	974	our $MODEL;
701		975
702	our $AUTOLOAD;	976	our $AUTOLOAD;
703	our @ISA;	977	our @ISA;
704		978
		979	our @REGISTRY;
		980
		981	our $WIN32;
		982
		983	BEGIN {
		984	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
		985	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		986
		987	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		988	if ${^TAINT};
		989	}
		990
705	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	991	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
706		992
707	our @REGISTRY;	993	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		994
		995	{
		996	my $idx;
		997	$PROTOCOL{$_} = ++$idx
		998	for reverse split /\s*,\s*/,
		999	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
		1000	}
708		1001
709	my @models = (	1002	my @models = (
710	[EV:: => AnyEvent::Impl::EV::],	1003	[EV:: => AnyEvent::Impl::EV::],
711	[Event:: => AnyEvent::Impl::Event::],	1004	[Event:: => AnyEvent::Impl::Event::],
712	[Tk:: => AnyEvent::Impl::Tk::],
713	[Wx:: => AnyEvent::Impl::POE::],
714	[Prima:: => AnyEvent::Impl::POE::],
715	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1005	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
716	# everything below here will not be autoprobed as the pureperl backend should work everywhere	1006	# everything below here will not be autoprobed
717	[Glib:: => AnyEvent::Impl::Glib::],	1007	# as the pureperl backend should work everywhere
		1008	# and is usually faster
		1009	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		1010	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
718	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1011	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
719	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1012	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
720	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1013	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		1014	[Wx:: => AnyEvent::Impl::POE::],
		1015	[Prima:: => AnyEvent::Impl::POE::],
		1016	# IO::Async is just too broken - we would need workaorunds for its
		1017	# byzantine signal and broken child handling, among others.
		1018	# IO::Async is rather hard to detect, as it doesn't have any
		1019	# obvious default class.
		1020	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1021	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1022	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
721	);	1023	);
722		1024
723	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	1025	our %method = map +($_ => 1),
		1026	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
724		1027
725	our @post_detect;	1028	our @post_detect;
726		1029
727	sub post_detect(&) {	1030	sub post_detect(&) {
728	my ($cb) = @_;	1031	my ($cb) = @_;
…		…
733	1	1036	1
734	} else {	1037	} else {
735	push @post_detect, $cb;	1038	push @post_detect, $cb;
736		1039
737	defined wantarray	1040	defined wantarray
738	? bless \$cb, "AnyEvent::Util::Guard"	1041	? bless \$cb, "AnyEvent::Util::postdetect"
739	: ()	1042	: ()
740	}	1043	}
741	}	1044	}
742		1045
743	sub AnyEvent::Util::Guard::DESTROY {	1046	sub AnyEvent::Util::postdetect::DESTROY {
744	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1047	@post_detect = grep $_ != ${$_[0]}, @post_detect;
745	}	1048	}
746		1049
747	sub detect() {	1050	sub detect() {
748	unless ($MODEL) {	1051	unless ($MODEL) {
749	no strict 'refs';	1052	no strict 'refs';
		1053	local $SIG{__DIE__};
750		1054
751	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1055	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
752	my $model = "AnyEvent::Impl::$1";	1056	my $model = "AnyEvent::Impl::$1";
753	if (eval "require $model") {	1057	if (eval "require $model") {
754	$MODEL = $model;	1058	$MODEL = $model;
…		…
784	last;	1088	last;
785	}	1089	}
786	}	1090	}
787		1091
788	$MODEL	1092	$MODEL
789	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1093	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
790	}	1094	}
791	}	1095	}
792		1096
		1097	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1098
793	unshift @ISA, $MODEL;	1099	unshift @ISA, $MODEL;
794	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1100
		1101	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
795		1102
796	(shift @post_detect)->() while @post_detect;	1103	(shift @post_detect)->() while @post_detect;
797	}	1104	}
798		1105
799	$MODEL	1106	$MODEL
…		…
809		1116
810	my $class = shift;	1117	my $class = shift;
811	$class->$func (@_);	1118	$class->$func (@_);
812	}	1119	}
813		1120
		1121	# utility function to dup a filehandle. this is used by many backends
		1122	# to support binding more than one watcher per filehandle (they usually
		1123	# allow only one watcher per fd, so we dup it to get a different one).
		1124	sub _dupfh($$;$$) {
		1125	my ($poll, $fh, $r, $w) = @_;
		1126
		1127	# cygwin requires the fh mode to be matching, unix doesn't
		1128	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1129	: $poll eq "w" ? ($w, ">")
		1130	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1131
		1132	open my $fh2, "$mode&" . fileno $fh
		1133	or die "cannot dup() filehandle: $!,";
		1134
		1135	# we assume CLOEXEC is already set by perl in all important cases
		1136
		1137	($fh2, $rw)
		1138	}
		1139
814	package AnyEvent::Base;	1140	package AnyEvent::Base;
815		1141
		1142	# default implementations for many methods
		1143
		1144	BEGIN {
		1145	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1146	*_time = \&Time::HiRes::time;
		1147	# if (eval "use POSIX (); (POSIX::times())...
		1148	} else {
		1149	*_time = sub { time }; # epic fail
		1150	}
		1151	}
		1152
		1153	sub time { _time }
		1154	sub now { _time }
		1155	sub now_update { }
		1156
816	# default implementation for ->condvar, ->wait, ->broadcast	1157	# default implementation for ->condvar
817		1158
818	sub condvar {	1159	sub condvar {
819	bless \my $flag, "AnyEvent::Base::CondVar"	1160	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
820	}
821
822	sub AnyEvent::Base::CondVar::broadcast {
823	${$_[0]}++;
824	}
825
826	sub AnyEvent::Base::CondVar::wait {
827	AnyEvent->one_event while !${$_[0]};
828	}	1161	}
829		1162
830	# default implementation for ->signal	1163	# default implementation for ->signal
831		1164
832	our %SIG_CB;	1165	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1166
		1167	sub _signal_exec {
		1168	sysread $SIGPIPE_R, my $dummy, 4;
		1169
		1170	while (%SIG_EV) {
		1171	for (keys %SIG_EV) {
		1172	delete $SIG_EV{$_};
		1173	$_->() for values %{ $SIG_CB{$_} || {} };
		1174	}
		1175	}
		1176	}
833		1177
834	sub signal {	1178	sub signal {
835	my (undef, %arg) = @_;	1179	my (undef, %arg) = @_;
836		1180
		1181	unless ($SIGPIPE_R) {
		1182	require Fcntl;
		1183
		1184	if (AnyEvent::WIN32) {
		1185	require AnyEvent::Util;
		1186
		1187	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1188	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1189	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1190	} else {
		1191	pipe $SIGPIPE_R, $SIGPIPE_W;
		1192	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1193	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1194
		1195	# not strictly required, as $^F is normally 2, but let's make sure...
		1196	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1197	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1198	}
		1199
		1200	$SIGPIPE_R
		1201	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1202
		1203	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1204	}
		1205
837	my $signal = uc $arg{signal}	1206	my $signal = uc $arg{signal}
838	or Carp::croak "required option 'signal' is missing";	1207	or Carp::croak "required option 'signal' is missing";
839		1208
840	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1209	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
841	$SIG{$signal} ||= sub {	1210	$SIG{$signal} ||= sub {
842	$_->() for values %{ $SIG_CB{$signal} || {} };	1211	local $!;
		1212	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1213	undef $SIG_EV{$signal};
843	};	1214	};
844		1215
845	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1216	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
846	}	1217	}
847		1218
848	sub AnyEvent::Base::Signal::DESTROY {	1219	sub AnyEvent::Base::signal::DESTROY {
849	my ($signal, $cb) = @{$_[0]};	1220	my ($signal, $cb) = @{$_[0]};
850		1221
851	delete $SIG_CB{$signal}{$cb};	1222	delete $SIG_CB{$signal}{$cb};
852		1223
		1224	# delete doesn't work with older perls - they then
		1225	# print weird messages, or just unconditionally exit
		1226	# instead of getting the default action.
853	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1227	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
854	}	1228	}
855		1229
856	# default implementation for ->child	1230	# default implementation for ->child
857		1231
858	our %PID_CB;	1232	our %PID_CB;
859	our $CHLD_W;	1233	our $CHLD_W;
860	our $CHLD_DELAY_W;	1234	our $CHLD_DELAY_W;
861	our $PID_IDLE;
862	our $WNOHANG;	1235	our $WNOHANG;
863		1236
864	sub _child_wait {	1237	sub _sigchld {
865	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1238	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
866	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1239	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
867	(values %{ $PID_CB{0} || {} });	1240	(values %{ $PID_CB{0} || {} });
868	}	1241	}
869
870	undef $PID_IDLE;
871	}
872
873	sub _sigchld {
874	# make sure we deliver these changes "synchronous" with the event loop.
875	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
876	undef $CHLD_DELAY_W;
877	&_child_wait;
878	});
879	}	1242	}
880		1243
881	sub child {	1244	sub child {
882	my (undef, %arg) = @_;	1245	my (undef, %arg) = @_;
883		1246
884	defined (my $pid = $arg{pid} + 0)	1247	defined (my $pid = $arg{pid} + 0)
885	or Carp::croak "required option 'pid' is missing";	1248	or Carp::croak "required option 'pid' is missing";
886		1249
887	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1250	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
888		1251
889	unless ($WNOHANG) {
890	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;	1252	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
891	}
892		1253
893	unless ($CHLD_W) {	1254	unless ($CHLD_W) {
894	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1255	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
895	# child could be a zombie already, so make at least one round	1256	# child could be a zombie already, so make at least one round
896	&_sigchld;	1257	&_sigchld;
897	}	1258	}
898		1259
899	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1260	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
900	}	1261	}
901		1262
902	sub AnyEvent::Base::Child::DESTROY {	1263	sub AnyEvent::Base::child::DESTROY {
903	my ($pid, $cb) = @{$_[0]};	1264	my ($pid, $cb) = @{$_[0]};
904		1265
905	delete $PID_CB{$pid}{$cb};	1266	delete $PID_CB{$pid}{$cb};
906	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1267	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
907		1268
908	undef $CHLD_W unless keys %PID_CB;	1269	undef $CHLD_W unless keys %PID_CB;
909	}	1270	}
		1271
		1272	# idle emulation is done by simply using a timer, regardless
		1273	# of whether the process is idle or not, and not letting
		1274	# the callback use more than 50% of the time.
		1275	sub idle {
		1276	my (undef, %arg) = @_;
		1277
		1278	my ($cb, $w, $rcb) = $arg{cb};
		1279
		1280	$rcb = sub {
		1281	if ($cb) {
		1282	$w = _time;
		1283	&$cb;
		1284	$w = _time - $w;
		1285
		1286	# never use more then 50% of the time for the idle watcher,
		1287	# within some limits
		1288	$w = 0.0001 if $w < 0.0001;
		1289	$w = 5 if $w > 5;
		1290
		1291	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1292	} else {
		1293	# clean up...
		1294	undef $w;
		1295	undef $rcb;
		1296	}
		1297	};
		1298
		1299	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1300
		1301	bless \\$cb, "AnyEvent::Base::idle"
		1302	}
		1303
		1304	sub AnyEvent::Base::idle::DESTROY {
		1305	undef $${$_[0]};
		1306	}
		1307
		1308	package AnyEvent::CondVar;
		1309
		1310	our @ISA = AnyEvent::CondVar::Base::;
		1311
		1312	package AnyEvent::CondVar::Base;
		1313
		1314	use overload
		1315	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1316	fallback => 1;
		1317
		1318	sub _send {
		1319	# nop
		1320	}
		1321
		1322	sub send {
		1323	my $cv = shift;
		1324	$cv->{_ae_sent} = [@_];
		1325	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1326	$cv->_send;
		1327	}
		1328
		1329	sub croak {
		1330	$_[0]{_ae_croak} = $_[1];
		1331	$_[0]->send;
		1332	}
		1333
		1334	sub ready {
		1335	$_[0]{_ae_sent}
		1336	}
		1337
		1338	sub _wait {
		1339	AnyEvent->one_event while !$_[0]{_ae_sent};
		1340	}
		1341
		1342	sub recv {
		1343	$_[0]->_wait;
		1344
		1345	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1346	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1347	}
		1348
		1349	sub cb {
		1350	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1351	$_[0]{_ae_cb}
		1352	}
		1353
		1354	sub begin {
		1355	++$_[0]{_ae_counter};
		1356	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1357	}
		1358
		1359	sub end {
		1360	return if --$_[0]{_ae_counter};
		1361	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
		1362	}
		1363
		1364	# undocumented/compatibility with pre-3.4
		1365	*broadcast = \&send;
		1366	*wait = \&_wait;
		1367
		1368	=head1 ERROR AND EXCEPTION HANDLING
		1369
		1370	In general, AnyEvent does not do any error handling - it relies on the
		1371	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1372	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1373	checking of all AnyEvent methods, however, which is highly useful during
		1374	development.
		1375
		1376	As for exception handling (i.e. runtime errors and exceptions thrown while
		1377	executing a callback), this is not only highly event-loop specific, but
		1378	also not in any way wrapped by this module, as this is the job of the main
		1379	program.
		1380
		1381	The pure perl event loop simply re-throws the exception (usually
		1382	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1383	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1384	so on.
		1385
		1386	=head1 ENVIRONMENT VARIABLES
		1387
		1388	The following environment variables are used by this module or its
		1389	submodules.
		1390
		1391	Note that AnyEvent will remove I<all> environment variables starting with
		1392	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1393	enabled.
		1394
		1395	=over 4
		1396
		1397	=item C<PERL_ANYEVENT_VERBOSE>
		1398
		1399	By default, AnyEvent will be completely silent except in fatal
		1400	conditions. You can set this environment variable to make AnyEvent more
		1401	talkative.
		1402
		1403	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1404	conditions, such as not being able to load the event model specified by
		1405	C<PERL_ANYEVENT_MODEL>.
		1406
		1407	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1408	model it chooses.
		1409
		1410	=item C<PERL_ANYEVENT_STRICT>
		1411
		1412	AnyEvent does not do much argument checking by default, as thorough
		1413	argument checking is very costly. Setting this variable to a true value
		1414	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1415	check the arguments passed to most method calls. If it finds any problems,
		1416	it will croak.
		1417
		1418	In other words, enables "strict" mode.
		1419
		1420	Unlike C<use strict>, it is definitely recommended to keep it off in
		1421	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1422	developing programs can be very useful, however.
		1423
		1424	=item C<PERL_ANYEVENT_MODEL>
		1425
		1426	This can be used to specify the event model to be used by AnyEvent, before
		1427	auto detection and -probing kicks in. It must be a string consisting
		1428	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1429	and the resulting module name is loaded and if the load was successful,
		1430	used as event model. If it fails to load AnyEvent will proceed with
		1431	auto detection and -probing.
		1432
		1433	This functionality might change in future versions.
		1434
		1435	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1436	could start your program like this:
		1437
		1438	PERL_ANYEVENT_MODEL=Perl perl ...
		1439
		1440	=item C<PERL_ANYEVENT_PROTOCOLS>
		1441
		1442	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1443	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1444	of auto probing).
		1445
		1446	Must be set to a comma-separated list of protocols or address families,
		1447	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1448	used, and preference will be given to protocols mentioned earlier in the
		1449	list.
		1450
		1451	This variable can effectively be used for denial-of-service attacks
		1452	against local programs (e.g. when setuid), although the impact is likely
		1453	small, as the program has to handle conenction and other failures anyways.
		1454
		1455	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1456	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1457	- only support IPv4, never try to resolve or contact IPv6
		1458	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1459	IPv6, but prefer IPv6 over IPv4.
		1460
		1461	=item C<PERL_ANYEVENT_EDNS0>
		1462
		1463	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1464	for DNS. This extension is generally useful to reduce DNS traffic, but
		1465	some (broken) firewalls drop such DNS packets, which is why it is off by
		1466	default.
		1467
		1468	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1469	EDNS0 in its DNS requests.
		1470
		1471	=item C<PERL_ANYEVENT_MAX_FORKS>
		1472
		1473	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1474	will create in parallel.
		1475
		1476	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1477
		1478	The default value for the C<max_outstanding> parameter for the default DNS
		1479	resolver - this is the maximum number of parallel DNS requests that are
		1480	sent to the DNS server.
		1481
		1482	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1483
		1484	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1485	configuration) in the default resolver. When set to the empty string, no
		1486	default config will be used.
		1487
		1488	=back
910		1489
911	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1490	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
912		1491
913	This is an advanced topic that you do not normally need to use AnyEvent in	1492	This is an advanced topic that you do not normally need to use AnyEvent in
914	a module. This section is only of use to event loop authors who want to	1493	a module. This section is only of use to event loop authors who want to
…		…
948		1527
949	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1528	I<rxvt-unicode> also cheats a bit by not providing blocking access to
950	condition variables: code blocking while waiting for a condition will	1529	condition variables: code blocking while waiting for a condition will
951	C<die>. This still works with most modules/usages, and blocking calls must	1530	C<die>. This still works with most modules/usages, and blocking calls must
952	not be done in an interactive application, so it makes sense.	1531	not be done in an interactive application, so it makes sense.
953
954	=head1 ENVIRONMENT VARIABLES
955
956	The following environment variables are used by this module:
957
958	=over 4
959
960	=item C<PERL_ANYEVENT_VERBOSE>
961
962	By default, AnyEvent will be completely silent except in fatal
963	conditions. You can set this environment variable to make AnyEvent more
964	talkative.
965
966	When set to C<1> or higher, causes AnyEvent to warn about unexpected
967	conditions, such as not being able to load the event model specified by
968	C<PERL_ANYEVENT_MODEL>.
969
970	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
971	model it chooses.
972
973	=item C<PERL_ANYEVENT_MODEL>
974
975	This can be used to specify the event model to be used by AnyEvent, before
976	autodetection and -probing kicks in. It must be a string consisting
977	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
978	and the resulting module name is loaded and if the load was successful,
979	used as event model. If it fails to load AnyEvent will proceed with
980	autodetection and -probing.
981
982	This functionality might change in future versions.
983
984	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
985	could start your program like this:
986
987	PERL_ANYEVENT_MODEL=Perl perl ...
988
989	=back
990		1532
991	=head1 EXAMPLE PROGRAM	1533	=head1 EXAMPLE PROGRAM
992		1534
993	The following program uses an I/O watcher to read data from STDIN, a timer	1535	The following program uses an I/O watcher to read data from STDIN, a timer
994	to display a message once per second, and a condition variable to quit the	1536	to display a message once per second, and a condition variable to quit the
…		…
1003	poll => 'r',	1545	poll => 'r',
1004	cb => sub {	1546	cb => sub {
1005	warn "io event <$_[0]>\n"; # will always output <r>	1547	warn "io event <$_[0]>\n"; # will always output <r>
1006	chomp (my $input = <STDIN>); # read a line	1548	chomp (my $input = <STDIN>); # read a line
1007	warn "read: $input\n"; # output what has been read	1549	warn "read: $input\n"; # output what has been read
1008	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1550	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1009	},	1551	},
1010	);	1552	);
1011		1553
1012	my $time_watcher; # can only be used once	1554	my $time_watcher; # can only be used once
1013		1555
…		…
1018	});	1560	});
1019	}	1561	}
1020		1562
1021	new_timer; # create first timer	1563	new_timer; # create first timer
1022		1564
1023	$cv->wait; # wait until user enters /^q/i	1565	$cv->recv; # wait until user enters /^q/i
1024		1566
1025	=head1 REAL-WORLD EXAMPLE	1567	=head1 REAL-WORLD EXAMPLE
1026		1568
1027	Consider the L<Net::FCP> module. It features (among others) the following	1569	Consider the L<Net::FCP> module. It features (among others) the following
1028	API calls, which are to freenet what HTTP GET requests are to http:	1570	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1078	syswrite $txn->{fh}, $txn->{request}	1620	syswrite $txn->{fh}, $txn->{request}
1079	or die "connection or write error";	1621	or die "connection or write error";
1080	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1622	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1081		1623
1082	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1624	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1083	result and signals any possible waiters that the request ahs finished:	1625	result and signals any possible waiters that the request has finished:
1084		1626
1085	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1627	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1086		1628
1087	if (end-of-file or data complete) {	1629	if (end-of-file or data complete) {
1088	$txn->{result} = $txn->{buf};	1630	$txn->{result} = $txn->{buf};
1089	$txn->{finished}->broadcast;	1631	$txn->{finished}->send;
1090	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1632	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1091	}	1633	}
1092		1634
1093	The C<result> method, finally, just waits for the finished signal (if the	1635	The C<result> method, finally, just waits for the finished signal (if the
1094	request was already finished, it doesn't wait, of course, and returns the	1636	request was already finished, it doesn't wait, of course, and returns the
1095	data:	1637	data:
1096		1638
1097	$txn->{finished}->wait;	1639	$txn->{finished}->recv;
1098	return $txn->{result};	1640	return $txn->{result};
1099		1641
1100	The actual code goes further and collects all errors (C<die>s, exceptions)	1642	The actual code goes further and collects all errors (C<die>s, exceptions)
1101	that occured during request processing. The C<result> method detects	1643	that occurred during request processing. The C<result> method detects
1102	whether an exception as thrown (it is stored inside the $txn object)	1644	whether an exception as thrown (it is stored inside the $txn object)
1103	and just throws the exception, which means connection errors and other	1645	and just throws the exception, which means connection errors and other
1104	problems get reported tot he code that tries to use the result, not in a	1646	problems get reported tot he code that tries to use the result, not in a
1105	random callback.	1647	random callback.
1106		1648
…		…
1137		1679
1138	my $quit = AnyEvent->condvar;	1680	my $quit = AnyEvent->condvar;
1139		1681
1140	$fcp->txn_client_get ($url)->cb (sub {	1682	$fcp->txn_client_get ($url)->cb (sub {
1141	...	1683	...
1142	$quit->broadcast;	1684	$quit->send;
1143	});	1685	});
1144		1686
1145	$quit->wait;	1687	$quit->recv;
1146		1688
1147		1689
1148	=head1 BENCHMARKS	1690	=head1 BENCHMARKS
1149		1691
1150	To give you an idea of the performance and overheads that AnyEvent adds	1692	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1152	of various event loops I prepared some benchmarks.	1694	of various event loops I prepared some benchmarks.
1153		1695
1154	=head2 BENCHMARKING ANYEVENT OVERHEAD	1696	=head2 BENCHMARKING ANYEVENT OVERHEAD
1155		1697
1156	Here is a benchmark of various supported event models used natively and	1698	Here is a benchmark of various supported event models used natively and
1157	through anyevent. The benchmark creates a lot of timers (with a zero	1699	through AnyEvent. The benchmark creates a lot of timers (with a zero
1158	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1700	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1159	which it is), lets them fire exactly once and destroys them again.	1701	which it is), lets them fire exactly once and destroys them again.
1160		1702
1161	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1703	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1162	distribution.	1704	distribution.
…		…
1179	all watchers, to avoid adding memory overhead. That means closure creation	1721	all watchers, to avoid adding memory overhead. That means closure creation
1180	and memory usage is not included in the figures.	1722	and memory usage is not included in the figures.
1181		1723
1182	I<invoke> is the time, in microseconds, used to invoke a simple	1724	I<invoke> is the time, in microseconds, used to invoke a simple
1183	callback. The callback simply counts down a Perl variable and after it was	1725	callback. The callback simply counts down a Perl variable and after it was
1184	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1726	invoked "watcher" times, it would C<< ->send >> a condvar once to
1185	signal the end of this phase.	1727	signal the end of this phase.
1186		1728
1187	I<destroy> is the time, in microseconds, that it takes to destroy a single	1729	I<destroy> is the time, in microseconds, that it takes to destroy a single
1188	watcher.	1730	watcher.
1189		1731
1190	=head3 Results	1732	=head3 Results
1191		1733
1192	name watchers bytes create invoke destroy comment	1734	name watchers bytes create invoke destroy comment
1193	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1735	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1194	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1736	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1195	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1737	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1196	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1738	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1197	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1739	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1198	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1740	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1741	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1742	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1199	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1743	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1200	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1744	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1201	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1745	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1202	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1746	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1203		1747
1204	=head3 Discussion	1748	=head3 Discussion
1205		1749
1206	The benchmark does I<not> measure scalability of the event loop very	1750	The benchmark does I<not> measure scalability of the event loop very
1207	well. For example, a select-based event loop (such as the pure perl one)	1751	well. For example, a select-based event loop (such as the pure perl one)
…		…
1232	performance becomes really bad with lots of file descriptors (and few of	1776	performance becomes really bad with lots of file descriptors (and few of
1233	them active), of course, but this was not subject of this benchmark.	1777	them active), of course, but this was not subject of this benchmark.
1234		1778
1235	The C<Event> module has a relatively high setup and callback invocation	1779	The C<Event> module has a relatively high setup and callback invocation
1236	cost, but overall scores in on the third place.	1780	cost, but overall scores in on the third place.
		1781
		1782	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1783	when using its pure perl backend.
1237		1784
1238	C<Glib>'s memory usage is quite a bit higher, but it features a	1785	C<Glib>'s memory usage is quite a bit higher, but it features a
1239	faster callback invocation and overall ends up in the same class as	1786	faster callback invocation and overall ends up in the same class as
1240	C<Event>. However, Glib scales extremely badly, doubling the number of	1787	C<Event>. However, Glib scales extremely badly, doubling the number of
1241	watchers increases the processing time by more than a factor of four,	1788	watchers increases the processing time by more than a factor of four,
…		…
1285		1832
1286	=back	1833	=back
1287		1834
1288	=head2 BENCHMARKING THE LARGE SERVER CASE	1835	=head2 BENCHMARKING THE LARGE SERVER CASE
1289		1836
1290	This benchmark atcually benchmarks the event loop itself. It works by	1837	This benchmark actually benchmarks the event loop itself. It works by
1291	creating a number of "servers": each server consists of a socketpair, a	1838	creating a number of "servers": each server consists of a socket pair, a
1292	timeout watcher that gets reset on activity (but never fires), and an I/O	1839	timeout watcher that gets reset on activity (but never fires), and an I/O
1293	watcher waiting for input on one side of the socket. Each time the socket	1840	watcher waiting for input on one side of the socket. Each time the socket
1294	watcher reads a byte it will write that byte to a random other "server".	1841	watcher reads a byte it will write that byte to a random other "server".
1295		1842
1296	The effect is that there will be a lot of I/O watchers, only part of which	1843	The effect is that there will be a lot of I/O watchers, only part of which
1297	are active at any one point (so there is a constant number of active	1844	are active at any one point (so there is a constant number of active
1298	fds for each loop iterstaion, but which fds these are is random). The	1845	fds for each loop iteration, but which fds these are is random). The
1299	timeout is reset each time something is read because that reflects how	1846	timeout is reset each time something is read because that reflects how
1300	most timeouts work (and puts extra pressure on the event loops).	1847	most timeouts work (and puts extra pressure on the event loops).
1301		1848
1302	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1849	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1303	(1%) are active. This mirrors the activity of large servers with many	1850	(1%) are active. This mirrors the activity of large servers with many
1304	connections, most of which are idle at any one point in time.	1851	connections, most of which are idle at any one point in time.
1305		1852
1306	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1853	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1307	distribution.	1854	distribution.
…		…
1309	=head3 Explanation of the columns	1856	=head3 Explanation of the columns
1310		1857
1311	I<sockets> is the number of sockets, and twice the number of "servers" (as	1858	I<sockets> is the number of sockets, and twice the number of "servers" (as
1312	each server has a read and write socket end).	1859	each server has a read and write socket end).
1313		1860
1314	I<create> is the time it takes to create a socketpair (which is	1861	I<create> is the time it takes to create a socket pair (which is
1315	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1862	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1316		1863
1317	I<request>, the most important value, is the time it takes to handle a	1864	I<request>, the most important value, is the time it takes to handle a
1318	single "request", that is, reading the token from the pipe and forwarding	1865	single "request", that is, reading the token from the pipe and forwarding
1319	it to another server. This includes deleting the old timeout and creating	1866	it to another server. This includes deleting the old timeout and creating
1320	a new one that moves the timeout into the future.	1867	a new one that moves the timeout into the future.
1321		1868
1322	=head3 Results	1869	=head3 Results
1323		1870
1324	name sockets create request	1871	name sockets create request
1325	EV 20000 69.01 11.16	1872	EV 20000 69.01 11.16
1326	Perl 20000 73.32 35.87	1873	Perl 20000 73.32 35.87
		1874	IOAsync 20000 157.00 98.14 epoll
		1875	IOAsync 20000 159.31 616.06 poll
1327	Event 20000 212.62 257.32	1876	Event 20000 212.62 257.32
1328	Glib 20000 651.16 1896.30	1877	Glib 20000 651.16 1896.30
1329	POE 20000 349.67 12317.24 uses POE::Loop::Event	1878	POE 20000 349.67 12317.24 uses POE::Loop::Event
1330		1879
1331	=head3 Discussion	1880	=head3 Discussion
1332		1881
1333	This benchmark I<does> measure scalability and overall performance of the	1882	This benchmark I<does> measure scalability and overall performance of the
1334	particular event loop.	1883	particular event loop.
…		…
1336	EV is again fastest. Since it is using epoll on my system, the setup time	1885	EV is again fastest. Since it is using epoll on my system, the setup time
1337	is relatively high, though.	1886	is relatively high, though.
1338		1887
1339	Perl surprisingly comes second. It is much faster than the C-based event	1888	Perl surprisingly comes second. It is much faster than the C-based event
1340	loops Event and Glib.	1889	loops Event and Glib.
		1890
		1891	IO::Async performs very well when using its epoll backend, and still quite
		1892	good compared to Glib when using its pure perl backend.
1341		1893
1342	Event suffers from high setup time as well (look at its code and you will	1894	Event suffers from high setup time as well (look at its code and you will
1343	understand why). Callback invocation also has a high overhead compared to	1895	understand why). Callback invocation also has a high overhead compared to
1344	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1896	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1345	uses select or poll in basically all documented configurations.	1897	uses select or poll in basically all documented configurations.
…		…
1392	speed most when you have lots of watchers, not when you only have a few of	1944	speed most when you have lots of watchers, not when you only have a few of
1393	them).	1945	them).
1394		1946
1395	EV is again fastest.	1947	EV is again fastest.
1396		1948
1397	Perl again comes second. It is noticably faster than the C-based event	1949	Perl again comes second. It is noticeably faster than the C-based event
1398	loops Event and Glib, although the difference is too small to really	1950	loops Event and Glib, although the difference is too small to really
1399	matter.	1951	matter.
1400		1952
1401	POE also performs much better in this case, but is is still far behind the	1953	POE also performs much better in this case, but is is still far behind the
1402	others.	1954	others.
…		…
1408	=item * C-based event loops perform very well with small number of	1960	=item * C-based event loops perform very well with small number of
1409	watchers, as the management overhead dominates.	1961	watchers, as the management overhead dominates.
1410		1962
1411	=back	1963	=back
1412		1964
		1965	=head2 THE IO::Lambda BENCHMARK
		1966
		1967	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1968	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1969	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		1970	shouldn't come as a surprise to anybody). As such, the benchmark is
		1971	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		1972	very optimal. But how would AnyEvent compare when used without the extra
		1973	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		1974
		1975	The benchmark itself creates an echo-server, and then, for 500 times,
		1976	connects to the echo server, sends a line, waits for the reply, and then
		1977	creates the next connection. This is a rather bad benchmark, as it doesn't
		1978	test the efficiency of the framework or much non-blocking I/O, but it is a
		1979	benchmark nevertheless.
		1980
		1981	name runtime
		1982	Lambda/select 0.330 sec
		1983	+ optimized 0.122 sec
		1984	Lambda/AnyEvent 0.327 sec
		1985	+ optimized 0.138 sec
		1986	Raw sockets/select 0.077 sec
		1987	POE/select, components 0.662 sec
		1988	POE/select, raw sockets 0.226 sec
		1989	POE/select, optimized 0.404 sec
		1990
		1991	AnyEvent/select/nb 0.085 sec
		1992	AnyEvent/EV/nb 0.068 sec
		1993	+state machine 0.134 sec
		1994
		1995	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		1996	benchmarks actually make blocking connects and use 100% blocking I/O,
		1997	defeating the purpose of an event-based solution. All of the newly
		1998	written AnyEvent benchmarks use 100% non-blocking connects (using
		1999	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2000	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2001	generally require a lot more bookkeeping and event handling than blocking
		2002	connects (which involve a single syscall only).
		2003
		2004	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2005	offers similar expressive power as POE and IO::Lambda, using conventional
		2006	Perl syntax. This means that both the echo server and the client are 100%
		2007	non-blocking, further placing it at a disadvantage.
		2008
		2009	As you can see, the AnyEvent + EV combination even beats the
		2010	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2011	backend easily beats IO::Lambda and POE.
		2012
		2013	And even the 100% non-blocking version written using the high-level (and
		2014	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2015	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2016	in a non-blocking way.
		2017
		2018	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2019	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2020	part of the IO::lambda distribution and were used without any changes.
		2021
		2022
		2023	=head1 SIGNALS
		2024
		2025	AnyEvent currently installs handlers for these signals:
		2026
		2027	=over 4
		2028
		2029	=item SIGCHLD
		2030
		2031	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2032	emulation for event loops that do not support them natively. Also, some
		2033	event loops install a similar handler.
		2034
		2035	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		2036	reset it to default, to avoid losing child exit statuses.
		2037
		2038	=item SIGPIPE
		2039
		2040	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2041	when AnyEvent gets loaded.
		2042
		2043	The rationale for this is that AnyEvent users usually do not really depend
		2044	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2045	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2046	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2047	some random socket.
		2048
		2049	The rationale for installing a no-op handler as opposed to ignoring it is
		2050	that this way, the handler will be restored to defaults on exec.
		2051
		2052	Feel free to install your own handler, or reset it to defaults.
		2053
		2054	=back
		2055
		2056	=cut
		2057
		2058	undef $SIG{CHLD}
		2059	if $SIG{CHLD} eq 'IGNORE';
		2060
		2061	$SIG{PIPE} = sub { }
		2062	unless defined $SIG{PIPE};
1413		2063
1414	=head1 FORK	2064	=head1 FORK
1415		2065
1416	Most event libraries are not fork-safe. The ones who are usually are	2066	Most event libraries are not fork-safe. The ones who are usually are
1417	because they rely on inefficient but fork-safe C<select> or C<poll>	2067	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1431	specified in the variable.	2081	specified in the variable.
1432		2082
1433	You can make AnyEvent completely ignore this variable by deleting it	2083	You can make AnyEvent completely ignore this variable by deleting it
1434	before the first watcher gets created, e.g. with a C<BEGIN> block:	2084	before the first watcher gets created, e.g. with a C<BEGIN> block:
1435		2085
1436	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	2086	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1437		2087
1438	use AnyEvent;	2088	use AnyEvent;
1439		2089
1440	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2090	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1441	be used to probe what backend is used and gain other information (which is	2091	be used to probe what backend is used and gain other information (which is
1442	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	2092	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		2093	$ENV{PERL_ANYEVENT_STRICT}.
		2094
		2095	Note that AnyEvent will remove I<all> environment variables starting with
		2096	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2097	enabled.
		2098
		2099
		2100	=head1 BUGS
		2101
		2102	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		2103	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		2104	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		2105	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		2106	pronounced).
1443		2107
1444		2108
1445	=head1 SEE ALSO	2109	=head1 SEE ALSO
		2110
		2111	Utility functions: L<AnyEvent::Util>.
1446		2112
1447	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2113	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1448	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2114	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1449		2115
1450	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2116	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1451	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2117	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1452	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2118	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1453	L<AnyEvent::Impl::POE>.	2119	L<AnyEvent::Impl::POE>.
1454		2120
		2121	Non-blocking file handles, sockets, TCP clients and
		2122	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		2123
		2124	Asynchronous DNS: L<AnyEvent::DNS>.
		2125
1455	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2126	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1456		2127
1457	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	2128	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1458		2129
1459		2130
1460	=head1 AUTHOR	2131	=head1 AUTHOR
1461		2132
1462	Marc Lehmann <schmorp@schmorp.de>	2133	Marc Lehmann <schmorp@schmorp.de>
1463	http://home.schmorp.de/	2134	http://home.schmorp.de/
1464		2135
1465	=cut	2136	=cut
1466		2137
1467	1	2138	1
1468		2139

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