ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.103 by root, Tue Apr 29 07:15:49 2008 UTC vs.
Revision 1.264 by root, Wed Jul 29 12:42:09 2009 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
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 ->broadcast	36	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->broadcast; # 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.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
22		53
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		55
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
27		58
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	59	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	60	policy> and AnyEvent is I<small and efficient>.
30		61
31	First and foremost, I<AnyEvent is not an event model> itself, it only	62	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	63	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,	64	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,	65	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	66	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	67	cannot change this, but it can hide the differences between those event
		68	loops.
37		69
38	The goal of AnyEvent is to offer module authors the ability to do event	70	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	71	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	72	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	73	module users into the same thing by forcing them to use the same event
42	model you use.	74	model you use.
43		75
44	For modules like POE or IO::Async (which is a total misnomer as it is	76	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	77	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	78	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	79	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	80	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.	81	module are I<also> forced to use the same event loop you use.
50		82
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	84	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	85	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,	86	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	87	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	88	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	89	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).	90	to AnyEvent, too, so it is future-proof).
59		91
60	In addition to being free of having to use I<the one and only true event	92	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	93	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	94	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	95	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	96	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	97	technically possible.
66		98
		99	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		100	of useful functionality, such as an asynchronous DNS resolver, 100%
		101	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		102	such as Windows) and lots of real-world knowledge and workarounds for
		103	platform bugs and differences.
		104
67	Of course, if you want lots of policy (this can arguably be somewhat	105	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	106	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	107	model, you should I<not> use this module.
70		108
71	=head1 DESCRIPTION	109	=head1 DESCRIPTION
72		110
…		…
78	The interface itself is vaguely similar, but not identical to the L<Event>	116	The interface itself is vaguely similar, but not identical to the L<Event>
79	module.	117	module.
80		118
81	During the first call of any watcher-creation method, the module tries	119	During the first call of any watcher-creation method, the module tries
82	to detect the currently loaded event loop by probing whether one of the	120	to detect the currently loaded event loop by probing whether one of the
83	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	121	following modules is already loaded: L<EV>,
84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	122	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
85	L<POE>. The first one found is used. If none are found, the module tries	123	L<POE>. The first one found is used. If none are found, the module tries
86	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	124	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
87	adaptor should always succeed) in the order given. The first one that can	125	adaptor should always succeed) in the order given. The first one that can
88	be successfully loaded will be used. If, after this, still none could be	126	be successfully loaded will be used. If, after this, still none could be
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	140	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...	141	use AnyEvent so their modules work together with others seamlessly...
104		142
105	The pure-perl implementation of AnyEvent is called	143	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	144	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	145	explicitly and enjoy the high availability of that event loop :)
108		146
109	=head1 WATCHERS	147	=head1 WATCHERS
110		148
111	AnyEvent has the central concept of a I<watcher>, which is an object that	149	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	150	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	151	the callback to call, the file handle to watch, etc.
114		152
115	These watchers are normal Perl objects with normal Perl lifetime. After	153	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	154	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	155	callback when the event occurs (of course, only when the event model
118	is in control).	156	is in control).
119		157
		158	Note that B<callbacks must not permanently change global variables>
		159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		160	callbacks must not C<die> >>. The former is good programming practise in
		161	Perl and the latter stems from the fact that exception handling differs
		162	widely between event loops.
		163
120	To disable the watcher you have to destroy it (e.g. by setting the	164	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	165	variable you store it in to C<undef> or otherwise deleting all references
122	to it).	166	to it).
123		167
124	All watchers are created by calling a method on the C<AnyEvent> class.	168	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
126	Many watchers either are used with "recursion" (repeating timers for	170	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	171	example), or need to refer to their watcher object in other ways.
128		172
129	An any way to achieve that is this pattern:	173	An any way to achieve that is this pattern:
130		174
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	176	# you can use $w here, for example to undef it
133	undef $w;	177	undef $w;
134	});	178	});
135		179
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	180	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	181	my variables are only visible after the statement in which they are
138	declared.	182	declared.
139		183
140	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
141		185
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	186	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	187	with the following mandatory key-value pairs as arguments:
144		188
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	189	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
		190	for events (AnyEvent might or might not keep a reference to this file
		191	handle). Note that only file handles pointing to things for which
		192	non-blocking operation makes sense are allowed. This includes sockets,
		193	most character devices, pipes, fifos and so on, but not for example files
		194	or block devices.
		195
146	for events. C<poll> must be a string that is either C<r> or C<w>,	196	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,	197	watcher waiting for "r"eadable or "w"ritable events, respectively.
		198
148	respectively. C<cb> is the callback to invoke each time the file handle	199	C<cb> is the callback to invoke each time the file handle becomes ready.
149	becomes ready.
150		200
151	Although the callback might get passed parameters, their value and	201	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	202	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	203	callbacks cannot use arguments passed to I/O watcher callbacks.
154		204
…		…
158		208
159	Some event loops issue spurious readyness notifications, so you should	209	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	210	always use non-blocking calls when reading/writing from/to your file
161	handles.	211	handles.
162		212
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	213	Example: wait for readability of STDIN, then read a line and disable the
		214	watcher.
		215
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	216	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	217	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	218	warn "read: $input\n";
169	undef $w;	219	undef $w;
170	});	220	});
…		…
180		230
181	Although the callback might get passed parameters, their value and	231	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	232	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	233	callbacks cannot use arguments passed to time watcher callbacks.
184		234
185	The timer callback will be invoked at most once: if you want a repeating	235	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	236	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	237	callback will be invoked regularly at that interval (in fractional
		238	seconds) after the first invocation. If C<interval> is specified with a
		239	false value, then it is treated as if it were missing.
188		240
189	Example:	241	The callback will be rescheduled before invoking the callback, but no
		242	attempt is done to avoid timer drift in most backends, so the interval is
		243	only approximate.
190		244
191	# fire an event after 7.7 seconds	245	Example: fire an event after 7.7 seconds.
		246
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	247	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	248	warn "timeout\n";
194	});	249	});
195		250
196	# to cancel the timer:	251	# to cancel the timer:
197	undef $w;	252	undef $w;
198		253
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	254	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		255
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	256	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		257	warn "timeout\n";
207	};	258	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		259
212	=head3 TIMING ISSUES	260	=head3 TIMING ISSUES
213		261
214	There are two ways to handle timers: based on real time (relative, "fire	262	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	263	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	275	timers.
228		276
229	AnyEvent always prefers relative timers, if available, matching the	277	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	278	AnyEvent API.
231		279
		280	AnyEvent has two additional methods that return the "current time":
		281
		282	=over 4
		283
		284	=item AnyEvent->time
		285
		286	This returns the "current wallclock time" as a fractional number of
		287	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		288	return, and the result is guaranteed to be compatible with those).
		289
		290	It progresses independently of any event loop processing, i.e. each call
		291	will check the system clock, which usually gets updated frequently.
		292
		293	=item AnyEvent->now
		294
		295	This also returns the "current wallclock time", but unlike C<time>, above,
		296	this value might change only once per event loop iteration, depending on
		297	the event loop (most return the same time as C<time>, above). This is the
		298	time that AnyEvent's timers get scheduled against.
		299
		300	I<In almost all cases (in all cases if you don't care), this is the
		301	function to call when you want to know the current time.>
		302
		303	This function is also often faster then C<< AnyEvent->time >>, and
		304	thus the preferred method if you want some timestamp (for example,
		305	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		306
		307	The rest of this section is only of relevance if you try to be very exact
		308	with your timing, you can skip it without bad conscience.
		309
		310	For a practical example of when these times differ, consider L<Event::Lib>
		311	and L<EV> and the following set-up:
		312
		313	The event loop is running and has just invoked one of your callback at
		314	time=500 (assume no other callbacks delay processing). In your callback,
		315	you wait a second by executing C<sleep 1> (blocking the process for a
		316	second) and then (at time=501) you create a relative timer that fires
		317	after three seconds.
		318
		319	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		320	both return C<501>, because that is the current time, and the timer will
		321	be scheduled to fire at time=504 (C<501> + C<3>).
		322
		323	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		324	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		325	last event processing phase started. With L<EV>, your timer gets scheduled
		326	to run at time=503 (C<500> + C<3>).
		327
		328	In one sense, L<Event::Lib> is more exact, as it uses the current time
		329	regardless of any delays introduced by event processing. However, most
		330	callbacks do not expect large delays in processing, so this causes a
		331	higher drift (and a lot more system calls to get the current time).
		332
		333	In another sense, L<EV> is more exact, as your timer will be scheduled at
		334	the same time, regardless of how long event processing actually took.
		335
		336	In either case, if you care (and in most cases, you don't), then you
		337	can get whatever behaviour you want with any event loop, by taking the
		338	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		339	account.
		340
		341	=item AnyEvent->now_update
		342
		343	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		344	the current time for each loop iteration (see the discussion of L<<
		345	AnyEvent->now >>, above).
		346
		347	When a callback runs for a long time (or when the process sleeps), then
		348	this "current" time will differ substantially from the real time, which
		349	might affect timers and time-outs.
		350
		351	When this is the case, you can call this method, which will update the
		352	event loop's idea of "current time".
		353
		354	Note that updating the time I<might> cause some events to be handled.
		355
		356	=back
		357
232	=head2 SIGNAL WATCHERS	358	=head2 SIGNAL WATCHERS
233		359
234	You can watch for signals using a signal watcher, C<signal> is the signal	360	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	361	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	362	callback to be invoked whenever a signal occurs.
237		363
238	Although the callback might get passed parameters, their value and	364	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	365	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	366	callbacks cannot use arguments passed to signal watcher callbacks.
241		367
242	Multiple signal occurances can be clumped together into one callback	368	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	369	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	370	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.	371	but it is guaranteed not to interrupt any other callbacks.
246		372
247	The main advantage of using these watchers is that you can share a signal	373	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	374	between multiple watchers, and AnyEvent will ensure that signals will not
		375	interrupt your program at bad times.
249		376
250	This watcher might use C<%SIG>, so programs overwriting those signals	377	This watcher might use C<%SIG> (depending on the event loop used),
251	directly will likely not work correctly.	378	so programs overwriting those signals directly will likely not work
		379	correctly.
252		380
253	Example: exit on SIGINT	381	Example: exit on SIGINT
254		382
255	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
256		384
		385	=head3 Signal Races, Delays and Workarounds
		386
		387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		388	callbacks to signals in a generic way, which is a pity, as you cannot do
		389	race-free signal handling in perl. AnyEvent will try to do it's best, but
		390	in some cases, signals will be delayed. The maximum time a signal might
		391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
		392	seconds). This variable can be changed only before the first signal
		393	watcher is created, and should be left alone otherwise. Higher values
		394	will cause fewer spurious wake-ups, which is better for power and CPU
		395	saving. All these problems can be avoided by installing the optional
		396	L<Async::Interrupt> module. This will not work with inherently broken
		397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
		398	currently, as POE does it's own workaround with one-second latency). With
		399	those, you just have to suffer the delays.
		400
257	=head2 CHILD PROCESS WATCHERS	401	=head2 CHILD PROCESS WATCHERS
258		402
259	You can also watch on a child process exit and catch its exit status.	403	You can also watch on a child process exit and catch its exit status.
260		404
261	The child process is specified by the C<pid> argument (if set to C<0>, it	405	The child process is specified by the C<pid> argument (one some backends,
262	watches for any child process exit). The watcher will trigger as often	406	using C<0> watches for any child process exit, on others this will
263	as status change for the child are received. This works by installing a	407	croak). The watcher will be triggered only when the child process has
264	signal handler for C<SIGCHLD>. The callback will be called with the pid	408	finished and an exit status is available, not on any trace events
265	and exit status (as returned by waitpid), so unlike other watcher types,	409	(stopped/continued).
266	you I<can> rely on child watcher callback arguments.	410
		411	The callback will be called with the pid and exit status (as returned by
		412	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		413	callback arguments.
		414
		415	This watcher type works by installing a signal handler for C<SIGCHLD>,
		416	and since it cannot be shared, nothing else should use SIGCHLD or reap
		417	random child processes (waiting for specific child processes, e.g. inside
		418	C<system>, is just fine).
267		419
268	There is a slight catch to child watchers, however: you usually start them	420	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	421	I<after> the child process was created, and this means the process could
270	have exited already (and no SIGCHLD will be sent anymore).	422	have exited already (and no SIGCHLD will be sent anymore).
271		423
272	Not all event models handle this correctly (POE doesn't), but even for	424	Not all event models handle this correctly (neither POE nor IO::Async do,
		425	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	426	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).	427	the process exits (i.e. before you fork in the first place). AnyEvent's
		428	pure perl event loop handles all cases correctly regardless of when you
		429	start the watcher.
275		430
276	This means you cannot create a child watcher as the very first thing in an	431	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	432	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>).	433	watcher before you C<fork> the child (alternatively, you can call
		434	C<AnyEvent::detect>).
		435
		436	As most event loops do not support waiting for child events, they will be
		437	emulated by AnyEvent in most cases, in which the latency and race problems
		438	mentioned in the description of signal watchers apply.
279		439
280	Example: fork a process and wait for it	440	Example: fork a process and wait for it
281		441
282	my $done = AnyEvent->condvar;	442	my $done = AnyEvent->condvar;
283		443
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	444	my $pid = fork or exit 5;
287		445
288	my $w = AnyEvent->child (	446	my $w = AnyEvent->child (
289	pid => $pid,	447	pid => $pid,
290	cb => sub {	448	cb => sub {
291	my ($pid, $status) = @_;	449	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	450	warn "pid $pid exited with status $status";
293	$done->broadcast;	451	$done->send;
294	},	452	},
295	);	453	);
296		454
297	# do something else, then wait for process exit	455	# do something else, then wait for process exit
298	$done->wait;	456	$done->recv;
		457
		458	=head2 IDLE WATCHERS
		459
		460	Sometimes there is a need to do something, but it is not so important
		461	to do it instantly, but only when there is nothing better to do. This
		462	"nothing better to do" is usually defined to be "no other events need
		463	attention by the event loop".
		464
		465	Idle watchers ideally get invoked when the event loop has nothing
		466	better to do, just before it would block the process to wait for new
		467	events. Instead of blocking, the idle watcher is invoked.
		468
		469	Most event loops unfortunately do not really support idle watchers (only
		470	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		471	will simply call the callback "from time to time".
		472
		473	Example: read lines from STDIN, but only process them when the
		474	program is otherwise idle:
		475
		476	my @lines; # read data
		477	my $idle_w;
		478	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		479	push @lines, scalar <STDIN>;
		480
		481	# start an idle watcher, if not already done
		482	$idle_w ||= AnyEvent->idle (cb => sub {
		483	# handle only one line, when there are lines left
		484	if (my $line = shift @lines) {
		485	print "handled when idle: $line";
		486	} else {
		487	# otherwise disable the idle watcher again
		488	undef $idle_w;
		489	}
		490	});
		491	});
299		492
300	=head2 CONDITION VARIABLES	493	=head2 CONDITION VARIABLES
301		494
		495	If you are familiar with some event loops you will know that all of them
		496	require you to run some blocking "loop", "run" or similar function that
		497	will actively watch for new events and call your callbacks.
		498
		499	AnyEvent is slightly different: it expects somebody else to run the event
		500	loop and will only block when necessary (usually when told by the user).
		501
		502	The instrument to do that is called a "condition variable", so called
		503	because they represent a condition that must become true.
		504
		505	Now is probably a good time to look at the examples further below.
		506
302	Condition variables can be created by calling the C<< AnyEvent->condvar >>	507	Condition variables can be created by calling the C<< AnyEvent->condvar
303	method without any arguments.	508	>> method, usually without arguments. The only argument pair allowed is
		509	C<cb>, which specifies a callback to be called when the condition variable
		510	becomes true, with the condition variable as the first argument (but not
		511	the results).
304		512
305	A condition variable waits for a condition - precisely that the C<<	513	After creation, the condition variable is "false" until it becomes "true"
306	->broadcast >> method has been called.	514	by calling the C<send> method (or calling the condition variable as if it
		515	were a callback, read about the caveats in the description for the C<<
		516	->send >> method).
307		517
308	They are very useful to signal that a condition has been fulfilled, for	518	Condition variables are similar to callbacks, except that you can
		519	optionally wait for them. They can also be called merge points - points
		520	in time where multiple outstanding events have been processed. And yet
		521	another way to call them is transactions - each condition variable can be
		522	used to represent a transaction, which finishes at some point and delivers
		523	a result. And yet some people know them as "futures" - a promise to
		524	compute/deliver something that you can wait for.
		525
		526	Condition variables are very useful to signal that something has finished,
309	example, if you write a module that does asynchronous http requests,	527	for example, if you write a module that does asynchronous http requests,
310	then a condition variable would be the ideal candidate to signal the	528	then a condition variable would be the ideal candidate to signal the
311	availability of results.	529	availability of results. The user can either act when the callback is
		530	called or can synchronously C<< ->recv >> for the results.
312		531
313	You can also use condition variables to block your main program until	532	You can also use them to simulate traditional event loops - for example,
314	an event occurs - for example, you could C<< ->wait >> in your main	533	you can block your main program until an event occurs - for example, you
315	program until the user clicks the Quit button in your app, which would C<<	534	could C<< ->recv >> in your main program until the user clicks the Quit
316	->broadcast >> the "quit" event.	535	button of your app, which would C<< ->send >> the "quit" event.
317		536
318	Note that condition variables recurse into the event loop - if you have	537	Note that condition variables recurse into the event loop - if you have
319	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	538	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
320	lose. Therefore, condition variables are good to export to your caller, but	539	lose. Therefore, condition variables are good to export to your caller, but
321	you should avoid making a blocking wait yourself, at least in callbacks,	540	you should avoid making a blocking wait yourself, at least in callbacks,
322	as this asks for trouble.	541	as this asks for trouble.
323		542
324	This object has two methods:	543	Condition variables are represented by hash refs in perl, and the keys
		544	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		545	easy (it is often useful to build your own transaction class on top of
		546	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		547	it's C<new> method in your own C<new> method.
325		548
326	=over 4	549	There are two "sides" to a condition variable - the "producer side" which
		550	eventually calls C<< -> send >>, and the "consumer side", which waits
		551	for the send to occur.
327		552
328	=item $cv->wait	553	Example: wait for a timer.
329
330	Wait (blocking if necessary) until the C<< ->broadcast >> method has been
331	called on c<$cv>, while servicing other watchers normally.
332
333	You can only wait once on a condition - additional calls will return
334	immediately.
335
336	Not all event models support a blocking wait - some die in that case
337	(programs might want to do that to stay interactive), so I<if you are
338	using this from a module, never require a blocking wait>, but let the
339	caller decide whether the call will block or not (for example, by coupling
340	condition variables with some kind of request results and supporting
341	callbacks so the caller knows that getting the result will not block,
342	while still suppporting blocking waits if the caller so desires).
343
344	Another reason I<never> to C<< ->wait >> in a module is that you cannot
345	sensibly have two C<< ->wait >>'s in parallel, as that would require
346	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
347	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and
348	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
349	from different coroutines, however).
350
351	=item $cv->broadcast
352
353	Flag the condition as ready - a running C<< ->wait >> and all further
354	calls to C<wait> will (eventually) return after this method has been
355	called. If nobody is waiting the broadcast will be remembered..
356
357	=back
358
359	Example:
360		554
361	# wait till the result is ready	555	# wait till the result is ready
362	my $result_ready = AnyEvent->condvar;	556	my $result_ready = AnyEvent->condvar;
363		557
364	# do something such as adding a timer	558	# do something such as adding a timer
365	# or socket watcher the calls $result_ready->broadcast	559	# or socket watcher the calls $result_ready->send
366	# when the "result" is ready.	560	# when the "result" is ready.
367	# in this case, we simply use a timer:	561	# in this case, we simply use a timer:
368	my $w = AnyEvent->timer (	562	my $w = AnyEvent->timer (
369	after => 1,	563	after => 1,
370	cb => sub { $result_ready->broadcast },	564	cb => sub { $result_ready->send },
371	);	565	);
372		566
373	# this "blocks" (while handling events) till the watcher	567	# this "blocks" (while handling events) till the callback
374	# calls broadcast	568	# calls -<send
375	$result_ready->wait;	569	$result_ready->recv;
		570
		571	Example: wait for a timer, but take advantage of the fact that condition
		572	variables are also callable directly.
		573
		574	my $done = AnyEvent->condvar;
		575	my $delay = AnyEvent->timer (after => 5, cb => $done);
		576	$done->recv;
		577
		578	Example: Imagine an API that returns a condvar and doesn't support
		579	callbacks. This is how you make a synchronous call, for example from
		580	the main program:
		581
		582	use AnyEvent::CouchDB;
		583
		584	...
		585
		586	my @info = $couchdb->info->recv;
		587
		588	And this is how you would just set a callback to be called whenever the
		589	results are available:
		590
		591	$couchdb->info->cb (sub {
		592	my @info = $_[0]->recv;
		593	});
		594
		595	=head3 METHODS FOR PRODUCERS
		596
		597	These methods should only be used by the producing side, i.e. the
		598	code/module that eventually sends the signal. Note that it is also
		599	the producer side which creates the condvar in most cases, but it isn't
		600	uncommon for the consumer to create it as well.
		601
		602	=over 4
		603
		604	=item $cv->send (...)
		605
		606	Flag the condition as ready - a running C<< ->recv >> and all further
		607	calls to C<recv> will (eventually) return after this method has been
		608	called. If nobody is waiting the send will be remembered.
		609
		610	If a callback has been set on the condition variable, it is called
		611	immediately from within send.
		612
		613	Any arguments passed to the C<send> call will be returned by all
		614	future C<< ->recv >> calls.
		615
		616	Condition variables are overloaded so one can call them directly (as if
		617	they were a code reference). Calling them directly is the same as calling
		618	C<send>.
		619
		620	=item $cv->croak ($error)
		621
		622	Similar to send, but causes all call's to C<< ->recv >> to invoke
		623	C<Carp::croak> with the given error message/object/scalar.
		624
		625	This can be used to signal any errors to the condition variable
		626	user/consumer. Doing it this way instead of calling C<croak> directly
		627	delays the error detetcion, but has the overwhelmign advantage that it
		628	diagnoses the error at the place where the result is expected, and not
		629	deep in some event clalback without connection to the actual code causing
		630	the problem.
		631
		632	=item $cv->begin ([group callback])
		633
		634	=item $cv->end
		635
		636	These two methods can be used to combine many transactions/events into
		637	one. For example, a function that pings many hosts in parallel might want
		638	to use a condition variable for the whole process.
		639
		640	Every call to C<< ->begin >> will increment a counter, and every call to
		641	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		642	>>, the (last) callback passed to C<begin> will be executed. That callback
		643	is I<supposed> to call C<< ->send >>, but that is not required. If no
		644	callback was set, C<send> will be called without any arguments.
		645
		646	You can think of C<< $cv->send >> giving you an OR condition (one call
		647	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		648	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		649
		650	Let's start with a simple example: you have two I/O watchers (for example,
		651	STDOUT and STDERR for a program), and you want to wait for both streams to
		652	close before activating a condvar:
		653
		654	my $cv = AnyEvent->condvar;
		655
		656	$cv->begin; # first watcher
		657	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		658	defined sysread $fh1, my $buf, 4096
		659	or $cv->end;
		660	});
		661
		662	$cv->begin; # second watcher
		663	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		664	defined sysread $fh2, my $buf, 4096
		665	or $cv->end;
		666	});
		667
		668	$cv->recv;
		669
		670	This works because for every event source (EOF on file handle), there is
		671	one call to C<begin>, so the condvar waits for all calls to C<end> before
		672	sending.
		673
		674	The ping example mentioned above is slightly more complicated, as the
		675	there are results to be passwd back, and the number of tasks that are
		676	begung can potentially be zero:
		677
		678	my $cv = AnyEvent->condvar;
		679
		680	my %result;
		681	$cv->begin (sub { $cv->send (\%result) });
		682
		683	for my $host (@list_of_hosts) {
		684	$cv->begin;
		685	ping_host_then_call_callback $host, sub {
		686	$result{$host} = ...;
		687	$cv->end;
		688	};
		689	}
		690
		691	$cv->end;
		692
		693	This code fragment supposedly pings a number of hosts and calls
		694	C<send> after results for all then have have been gathered - in any
		695	order. To achieve this, the code issues a call to C<begin> when it starts
		696	each ping request and calls C<end> when it has received some result for
		697	it. Since C<begin> and C<end> only maintain a counter, the order in which
		698	results arrive is not relevant.
		699
		700	There is an additional bracketing call to C<begin> and C<end> outside the
		701	loop, which serves two important purposes: first, it sets the callback
		702	to be called once the counter reaches C<0>, and second, it ensures that
		703	C<send> is called even when C<no> hosts are being pinged (the loop
		704	doesn't execute once).
		705
		706	This is the general pattern when you "fan out" into multiple (but
		707	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
		708	the callback and ensure C<end> is called at least once, and then, for each
		709	subrequest you start, call C<begin> and for each subrequest you finish,
		710	call C<end>.
		711
		712	=back
		713
		714	=head3 METHODS FOR CONSUMERS
		715
		716	These methods should only be used by the consuming side, i.e. the
		717	code awaits the condition.
		718
		719	=over 4
		720
		721	=item $cv->recv
		722
		723	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
		724	>> methods have been called on c<$cv>, while servicing other watchers
		725	normally.
		726
		727	You can only wait once on a condition - additional calls are valid but
		728	will return immediately.
		729
		730	If an error condition has been set by calling C<< ->croak >>, then this
		731	function will call C<croak>.
		732
		733	In list context, all parameters passed to C<send> will be returned,
		734	in scalar context only the first one will be returned.
		735
		736	Note that doing a blocking wait in a callback is not supported by any
		737	event loop, that is, recursive invocation of a blocking C<< ->recv
		738	>> is not allowed, and the C<recv> call will C<croak> if such a
		739	condition is detected. This condition can be slightly loosened by using
		740	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		741	any thread that doesn't run the event loop itself.
		742
		743	Not all event models support a blocking wait - some die in that case
		744	(programs might want to do that to stay interactive), so I<if you are
		745	using this from a module, never require a blocking wait>. Instead, let the
		746	caller decide whether the call will block or not (for example, by coupling
		747	condition variables with some kind of request results and supporting
		748	callbacks so the caller knows that getting the result will not block,
		749	while still supporting blocking waits if the caller so desires).
		750
		751	You can ensure that C<< -recv >> never blocks by setting a callback and
		752	only calling C<< ->recv >> from within that callback (or at a later
		753	time). This will work even when the event loop does not support blocking
		754	waits otherwise.
		755
		756	=item $bool = $cv->ready
		757
		758	Returns true when the condition is "true", i.e. whether C<send> or
		759	C<croak> have been called.
		760
		761	=item $cb = $cv->cb ($cb->($cv))
		762
		763	This is a mutator function that returns the callback set and optionally
		764	replaces it before doing so.
		765
		766	The callback will be called when the condition becomes "true", i.e. when
		767	C<send> or C<croak> are called, with the only argument being the condition
		768	variable itself. Calling C<recv> inside the callback or at any later time
		769	is guaranteed not to block.
		770
		771	=back
		772
		773	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		774
		775	The available backend classes are (every class has its own manpage):
		776
		777	=over 4
		778
		779	=item Backends that are autoprobed when no other event loop can be found.
		780
		781	EV is the preferred backend when no other event loop seems to be in
		782	use. If EV is not installed, then AnyEvent will try Event, and, failing
		783	that, will fall back to its own pure-perl implementation, which is
		784	available everywhere as it comes with AnyEvent itself.
		785
		786	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		787	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		788	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		789
		790	=item Backends that are transparently being picked up when they are used.
		791
		792	These will be used when they are currently loaded when the first watcher
		793	is created, in which case it is assumed that the application is using
		794	them. This means that AnyEvent will automatically pick the right backend
		795	when the main program loads an event module before anything starts to
		796	create watchers. Nothing special needs to be done by the main program.
		797
		798	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		799	AnyEvent::Impl::Tk based on Tk, very broken.
		800	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		801	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		802	AnyEvent::Impl::Irssi used when running within irssi.
		803
		804	=item Backends with special needs.
		805
		806	Qt requires the Qt::Application to be instantiated first, but will
		807	otherwise be picked up automatically. As long as the main program
		808	instantiates the application before any AnyEvent watchers are created,
		809	everything should just work.
		810
		811	AnyEvent::Impl::Qt based on Qt.
		812
		813	Support for IO::Async can only be partial, as it is too broken and
		814	architecturally limited to even support the AnyEvent API. It also
		815	is the only event loop that needs the loop to be set explicitly, so
		816	it can only be used by a main program knowing about AnyEvent. See
		817	L<AnyEvent::Impl::Async> for the gory details.
		818
		819	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		820
		821	=item Event loops that are indirectly supported via other backends.
		822
		823	Some event loops can be supported via other modules:
		824
		825	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		826
		827	B<WxWidgets> has no support for watching file handles. However, you can
		828	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		829	polls 20 times per second, which was considered to be too horrible to even
		830	consider for AnyEvent.
		831
		832	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		833	backend, so it can be supported through POE.
		834
		835	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		836	load L<POE> when detecting them, in the hope that POE will pick them up,
		837	in which case everything will be automatic.
		838
		839	=back
376		840
377	=head1 GLOBAL VARIABLES AND FUNCTIONS	841	=head1 GLOBAL VARIABLES AND FUNCTIONS
378		842
		843	These are not normally required to use AnyEvent, but can be useful to
		844	write AnyEvent extension modules.
		845
379	=over 4	846	=over 4
380		847
381	=item $AnyEvent::MODEL	848	=item $AnyEvent::MODEL
382		849
383	Contains C<undef> until the first watcher is being created. Then it	850	Contains C<undef> until the first watcher is being created, before the
		851	backend has been autodetected.
		852
384	contains the event model that is being used, which is the name of the	853	Afterwards it contains the event model that is being used, which is the
385	Perl class implementing the model. This class is usually one of the	854	name of the Perl class implementing the model. This class is usually one
386	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	855	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
387	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	856	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
388		857	will be C<urxvt::anyevent>).
389	The known classes so far are:
390
391	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
392	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
393	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
394	AnyEvent::Impl::Event based on Event, second best choice.
395	AnyEvent::Impl::Glib based on Glib, third-best choice.
396	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
397	AnyEvent::Impl::Tk based on Tk, very bad choice.
398	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
399	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
400	AnyEvent::Impl::POE based on POE, not generic enough for full support.
401
402	There is no support for WxWidgets, as WxWidgets has no support for
403	watching file handles. However, you can use WxWidgets through the
404	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
405	second, which was considered to be too horrible to even consider for
406	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
407	it's adaptor.
408
409	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
410	autodetecting them.
411		858
412	=item AnyEvent::detect	859	=item AnyEvent::detect
413		860
414	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	861	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
415	if necessary. You should only call this function right before you would	862	if necessary. You should only call this function right before you would
416	have created an AnyEvent watcher anyway, that is, as late as possible at	863	have created an AnyEvent watcher anyway, that is, as late as possible at
417	runtime.	864	runtime, and not e.g. while initialising of your module.
		865
		866	If you need to do some initialisation before AnyEvent watchers are
		867	created, use C<post_detect>.
		868
		869	=item $guard = AnyEvent::post_detect { BLOCK }
		870
		871	Arranges for the code block to be executed as soon as the event model is
		872	autodetected (or immediately if this has already happened).
		873
		874	The block will be executed I<after> the actual backend has been detected
		875	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		876	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		877	other initialisations - see the sources of L<AnyEvent::Strict> or
		878	L<AnyEvent::AIO> to see how this is used.
		879
		880	The most common usage is to create some global watchers, without forcing
		881	event module detection too early, for example, L<AnyEvent::AIO> creates
		882	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		883	avoid autodetecting the event module at load time.
		884
		885	If called in scalar or list context, then it creates and returns an object
		886	that automatically removes the callback again when it is destroyed (or
		887	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
		888	a case where this is useful.
		889
		890	Example: Create a watcher for the IO::AIO module and store it in
		891	C<$WATCHER>. Only do so after the event loop is initialised, though.
		892
		893	our WATCHER;
		894
		895	my $guard = AnyEvent::post_detect {
		896	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		897	};
		898
		899	# the ||= is important in case post_detect immediately runs the block,
		900	# as to not clobber the newly-created watcher. assigning both watcher and
		901	# post_detect guard to the same variable has the advantage of users being
		902	# able to just C<undef $WATCHER> if the watcher causes them grief.
		903
		904	$WATCHER ||= $guard;
		905
		906	=item @AnyEvent::post_detect
		907
		908	If there are any code references in this array (you can C<push> to it
		909	before or after loading AnyEvent), then they will called directly after
		910	the event loop has been chosen.
		911
		912	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		913	if it is defined then the event loop has already been detected, and the
		914	array will be ignored.
		915
		916	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		917	it,as it takes care of these details.
		918
		919	This variable is mainly useful for modules that can do something useful
		920	when AnyEvent is used and thus want to know when it is initialised, but do
		921	not need to even load it by default. This array provides the means to hook
		922	into AnyEvent passively, without loading it.
418		923
419	=back	924	=back
420		925
421	=head1 WHAT TO DO IN A MODULE	926	=head1 WHAT TO DO IN A MODULE
422		927
…		…
426	Be careful when you create watchers in the module body - AnyEvent will	931	Be careful when you create watchers in the module body - AnyEvent will
427	decide which event module to use as soon as the first method is called, so	932	decide which event module to use as soon as the first method is called, so
428	by calling AnyEvent in your module body you force the user of your module	933	by calling AnyEvent in your module body you force the user of your module
429	to load the event module first.	934	to load the event module first.
430		935
431	Never call C<< ->wait >> on a condition variable unless you I<know> that	936	Never call C<< ->recv >> on a condition variable unless you I<know> that
432	the C<< ->broadcast >> method has been called on it already. This is	937	the C<< ->send >> method has been called on it already. This is
433	because it will stall the whole program, and the whole point of using	938	because it will stall the whole program, and the whole point of using
434	events is to stay interactive.	939	events is to stay interactive.
435		940
436	It is fine, however, to call C<< ->wait >> when the user of your module	941	It is fine, however, to call C<< ->recv >> when the user of your module
437	requests it (i.e. if you create a http request object ad have a method	942	requests it (i.e. if you create a http request object ad have a method
438	called C<results> that returns the results, it should call C<< ->wait >>	943	called C<results> that returns the results, it should call C<< ->recv >>
439	freely, as the user of your module knows what she is doing. always).	944	freely, as the user of your module knows what she is doing. always).
440		945
441	=head1 WHAT TO DO IN THE MAIN PROGRAM	946	=head1 WHAT TO DO IN THE MAIN PROGRAM
442		947
443	There will always be a single main program - the only place that should	948	There will always be a single main program - the only place that should
…		…
445		950
446	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	951	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
447	do anything special (it does not need to be event-based) and let AnyEvent	952	do anything special (it does not need to be event-based) and let AnyEvent
448	decide which implementation to chose if some module relies on it.	953	decide which implementation to chose if some module relies on it.
449		954
450	If the main program relies on a specific event model. For example, in	955	If the main program relies on a specific event model - for example, in
451	Gtk2 programs you have to rely on the Glib module. You should load the	956	Gtk2 programs you have to rely on the Glib module - you should load the
452	event module before loading AnyEvent or any module that uses it: generally	957	event module before loading AnyEvent or any module that uses it: generally
453	speaking, you should load it as early as possible. The reason is that	958	speaking, you should load it as early as possible. The reason is that
454	modules might create watchers when they are loaded, and AnyEvent will	959	modules might create watchers when they are loaded, and AnyEvent will
455	decide on the event model to use as soon as it creates watchers, and it	960	decide on the event model to use as soon as it creates watchers, and it
456	might chose the wrong one unless you load the correct one yourself.	961	might chose the wrong one unless you load the correct one yourself.
457		962
458	You can chose to use a rather inefficient pure-perl implementation by	963	You can chose to use a pure-perl implementation by loading the
459	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	964	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
460	behaviour everywhere, but letting AnyEvent chose is generally better.	965	everywhere, but letting AnyEvent chose the model is generally better.
		966
		967	=head2 MAINLOOP EMULATION
		968
		969	Sometimes (often for short test scripts, or even standalone programs who
		970	only want to use AnyEvent), you do not want to run a specific event loop.
		971
		972	In that case, you can use a condition variable like this:
		973
		974	AnyEvent->condvar->recv;
		975
		976	This has the effect of entering the event loop and looping forever.
		977
		978	Note that usually your program has some exit condition, in which case
		979	it is better to use the "traditional" approach of storing a condition
		980	variable somewhere, waiting for it, and sending it when the program should
		981	exit cleanly.
		982
461		983
462	=head1 OTHER MODULES	984	=head1 OTHER MODULES
463		985
464	The following is a non-exhaustive list of additional modules that use	986	The following is a non-exhaustive list of additional modules that use
465	AnyEvent and can therefore be mixed easily with other AnyEvent modules	987	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
466	in the same program. Some of the modules come with AnyEvent, some are	988	modules and other event loops in the same program. Some of the modules
467	available via CPAN.	989	come with AnyEvent, most are available via CPAN.
468		990
469	=over 4	991	=over 4
470		992
471	=item L<AnyEvent::Util>	993	=item L<AnyEvent::Util>
472		994
473	Contains various utility functions that replace often-used but blocking	995	Contains various utility functions that replace often-used but blocking
474	functions such as C<inet_aton> by event-/callback-based versions.	996	functions such as C<inet_aton> by event-/callback-based versions.
475		997
		998	=item L<AnyEvent::Socket>
		999
		1000	Provides various utility functions for (internet protocol) sockets,
		1001	addresses and name resolution. Also functions to create non-blocking tcp
		1002	connections or tcp servers, with IPv6 and SRV record support and more.
		1003
476	=item L<AnyEvent::Handle>	1004	=item L<AnyEvent::Handle>
477		1005
478	Provide read and write buffers and manages watchers for reads and writes.	1006	Provide read and write buffers, manages watchers for reads and writes,
		1007	supports raw and formatted I/O, I/O queued and fully transparent and
		1008	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
479		1009
480	=item L<AnyEvent::Socket>	1010	=item L<AnyEvent::DNS>
481		1011
482	Provides a means to do non-blocking connects, accepts etc.	1012	Provides rich asynchronous DNS resolver capabilities.
		1013
		1014	=item L<AnyEvent::HTTP>
		1015
		1016	A simple-to-use HTTP library that is capable of making a lot of concurrent
		1017	HTTP requests.
483		1018
484	=item L<AnyEvent::HTTPD>	1019	=item L<AnyEvent::HTTPD>
485		1020
486	Provides a simple web application server framework.	1021	Provides a simple web application server framework.
487		1022
488	=item L<AnyEvent::DNS>
489
490	Provides asynchronous DNS resolver capabilities, beyond what
491	L<AnyEvent::Util> offers.
492
493	=item L<AnyEvent::FastPing>	1023	=item L<AnyEvent::FastPing>
494		1024
495	The fastest ping in the west.	1025	The fastest ping in the west.
496		1026
		1027	=item L<AnyEvent::DBI>
		1028
		1029	Executes L<DBI> requests asynchronously in a proxy process.
		1030
		1031	=item L<AnyEvent::AIO>
		1032
		1033	Truly asynchronous I/O, should be in the toolbox of every event
		1034	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		1035	together.
		1036
		1037	=item L<AnyEvent::BDB>
		1038
		1039	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		1040	L<BDB> and AnyEvent together.
		1041
		1042	=item L<AnyEvent::GPSD>
		1043
		1044	A non-blocking interface to gpsd, a daemon delivering GPS information.
		1045
497	=item L<Net::IRC3>	1046	=item L<AnyEvent::IRC>
498		1047
499	AnyEvent based IRC client module family.	1048	AnyEvent based IRC client module family (replacing the older Net::IRC3).
500		1049
501	=item L<Net::XMPP2>	1050	=item L<AnyEvent::XMPP>
502		1051
503	AnyEvent based XMPP (Jabber protocol) module family.	1052	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1053	Net::XMPP2>.
		1054
		1055	=item L<AnyEvent::IGS>
		1056
		1057	A non-blocking interface to the Internet Go Server protocol (used by
		1058	L<App::IGS>).
504		1059
505	=item L<Net::FCP>	1060	=item L<Net::FCP>
506		1061
507	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1062	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
508	of AnyEvent.	1063	of AnyEvent.
…		…
511		1066
512	High level API for event-based execution flow control.	1067	High level API for event-based execution flow control.
513		1068
514	=item L<Coro>	1069	=item L<Coro>
515		1070
516	Has special support for AnyEvent.	1071	Has special support for AnyEvent via L<Coro::AnyEvent>.
517
518	=item L<IO::Lambda>
519
520	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
521
522	=item L<IO::AIO>
523
524	Truly asynchronous I/O, should be in the toolbox of every event
525	programmer. Can be trivially made to use AnyEvent.
526
527	=item L<BDB>
528
529	Truly asynchronous Berkeley DB access. Can be trivially made to use
530	AnyEvent.
531		1072
532	=back	1073	=back
533		1074
534	=cut	1075	=cut
535		1076
536	package AnyEvent;	1077	package AnyEvent;
537		1078
		1079	# basically a tuned-down version of common::sense
		1080	sub common_sense {
538	no warnings;	1081	# no warnings
539	use strict;	1082	${^WARNING_BITS} ^= ${^WARNING_BITS};
		1083	# use strict vars subs
		1084	$^H |= 0x00000600;
		1085	}
540		1086
		1087	BEGIN { AnyEvent::common_sense }
		1088
541	use Carp;	1089	use Carp ();
542		1090
543	our $VERSION = '3.3';	1091	our $VERSION = 4.881;
544	our $MODEL;	1092	our $MODEL;
545		1093
546	our $AUTOLOAD;	1094	our $AUTOLOAD;
547	our @ISA;	1095	our @ISA;
548		1096
549	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
550
551	our @REGISTRY;	1097	our @REGISTRY;
552		1098
		1099	our $WIN32;
		1100
		1101	our $VERBOSE;
		1102
		1103	BEGIN {
		1104	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
		1105	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		1106
		1107	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1108	if ${^TAINT};
		1109
		1110	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1111
		1112	}
		1113
		1114	our $MAX_SIGNAL_LATENCY = 10;
		1115
		1116	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1117
		1118	{
		1119	my $idx;
		1120	$PROTOCOL{$_} = ++$idx
		1121	for reverse split /\s*,\s*/,
		1122	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
		1123	}
		1124
553	my @models = (	1125	my @models = (
554	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
555	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
556	[EV:: => AnyEvent::Impl::EV::],	1126	[EV:: => AnyEvent::Impl::EV:: , 1],
557	[Event:: => AnyEvent::Impl::Event::],	1127	[Event:: => AnyEvent::Impl::Event::, 1],
558	[Glib:: => AnyEvent::Impl::Glib::],	1128	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
		1129	# everything below here will not (normally) be autoprobed
		1130	# as the pureperl backend should work everywhere
		1131	# and is usually faster
		1132	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1133	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1134	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
559	[Tk:: => AnyEvent::Impl::Tk::],	1135	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		1136	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
		1137	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
560	[Wx:: => AnyEvent::Impl::POE::],	1138	[Wx:: => AnyEvent::Impl::POE::],
561	[Prima:: => AnyEvent::Impl::POE::],	1139	[Prima:: => AnyEvent::Impl::POE::],
562	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1140	# IO::Async is just too broken - we would need workarounds for its
563	# everything below here will not be autoprobed as the pureperl backend should work everywhere	1141	# byzantine signal and broken child handling, among others.
564	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1142	# IO::Async is rather hard to detect, as it doesn't have any
		1143	# obvious default class.
565	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1144	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
566	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1145	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1146	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
567	);	1147	);
568		1148
569	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	1149	our %method = map +($_ => 1),
		1150	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
		1151
		1152	our @post_detect;
		1153
		1154	sub post_detect(&) {
		1155	my ($cb) = @_;
		1156
		1157	if ($MODEL) {
		1158	$cb->();
		1159
		1160	undef
		1161	} else {
		1162	push @post_detect, $cb;
		1163
		1164	defined wantarray
		1165	? bless \$cb, "AnyEvent::Util::postdetect"
		1166	: ()
		1167	}
		1168	}
		1169
		1170	sub AnyEvent::Util::postdetect::DESTROY {
		1171	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1172	}
570		1173
571	sub detect() {	1174	sub detect() {
572	unless ($MODEL) {	1175	unless ($MODEL) {
573	no strict 'refs';	1176	local $SIG{__DIE__};
574		1177
575	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1178	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
576	my $model = "AnyEvent::Impl::$1";	1179	my $model = "AnyEvent::Impl::$1";
577	if (eval "require $model") {	1180	if (eval "require $model") {
578	$MODEL = $model;	1181	$MODEL = $model;
579	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1182	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
580	} else {	1183	} else {
581	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1184	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
582	}	1185	}
583	}	1186	}
584		1187
585	# check for already loaded models	1188	# check for already loaded models
586	unless ($MODEL) {	1189	unless ($MODEL) {
587	for (@REGISTRY, @models) {	1190	for (@REGISTRY, @models) {
588	my ($package, $model) = @$_;	1191	my ($package, $model) = @$_;
589	if (${"$package\::VERSION"} > 0) {	1192	if (${"$package\::VERSION"} > 0) {
590	if (eval "require $model") {	1193	if (eval "require $model") {
591	$MODEL = $model;	1194	$MODEL = $model;
592	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1195	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
593	last;	1196	last;
594	}	1197	}
595	}	1198	}
596	}	1199	}
597		1200
598	unless ($MODEL) {	1201	unless ($MODEL) {
599	# try to load a model	1202	# try to autoload a model
600
601	for (@REGISTRY, @models) {	1203	for (@REGISTRY, @models) {
602	my ($package, $model) = @$_;	1204	my ($package, $model, $autoload) = @$_;
		1205	if (
		1206	$autoload
603	if (eval "require $package"	1207	and eval "require $package"
604	and ${"$package\::VERSION"} > 0	1208	and ${"$package\::VERSION"} > 0
605	and eval "require $model") {	1209	and eval "require $model"
		1210	) {
606	$MODEL = $model;	1211	$MODEL = $model;
607	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1212	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
608	last;	1213	last;
609	}	1214	}
610	}	1215	}
611		1216
612	$MODEL	1217	$MODEL
613	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";	1218	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
614	}	1219	}
615	}	1220	}
616		1221
		1222	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1223
617	unshift @ISA, $MODEL;	1224	unshift @ISA, $MODEL;
618	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1225
		1226	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1227
		1228	(shift @post_detect)->() while @post_detect;
619	}	1229	}
620		1230
621	$MODEL	1231	$MODEL
622	}	1232	}
623		1233
624	sub AUTOLOAD {	1234	sub AUTOLOAD {
625	(my $func = $AUTOLOAD) =~ s/.*://;	1235	(my $func = $AUTOLOAD) =~ s/.*://;
626		1236
627	$method{$func}	1237	$method{$func}
628	or croak "$func: not a valid method for AnyEvent objects";	1238	or Carp::croak "$func: not a valid method for AnyEvent objects";
629		1239
630	detect unless $MODEL;	1240	detect unless $MODEL;
631		1241
632	my $class = shift;	1242	my $class = shift;
633	$class->$func (@_);	1243	$class->$func (@_);
634	}	1244	}
635		1245
		1246	# utility function to dup a filehandle. this is used by many backends
		1247	# to support binding more than one watcher per filehandle (they usually
		1248	# allow only one watcher per fd, so we dup it to get a different one).
		1249	sub _dupfh($$;$$) {
		1250	my ($poll, $fh, $r, $w) = @_;
		1251
		1252	# cygwin requires the fh mode to be matching, unix doesn't
		1253	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
		1254
		1255	open my $fh2, $mode, $fh
		1256	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
		1257
		1258	# we assume CLOEXEC is already set by perl in all important cases
		1259
		1260	($fh2, $rw)
		1261	}
		1262
636	package AnyEvent::Base;	1263	package AnyEvent::Base;
637		1264
		1265	# default implementations for many methods
		1266
		1267	sub _time {
		1268	# probe for availability of Time::HiRes
		1269	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1270	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
		1271	*_time = \&Time::HiRes::time;
		1272	# if (eval "use POSIX (); (POSIX::times())...
		1273	} else {
		1274	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
		1275	*_time = sub { time }; # epic fail
		1276	}
		1277
		1278	&_time
		1279	}
		1280
		1281	sub time { _time }
		1282	sub now { _time }
		1283	sub now_update { }
		1284
638	# default implementation for ->condvar, ->wait, ->broadcast	1285	# default implementation for ->condvar
639		1286
640	sub condvar {	1287	sub condvar {
641	bless \my $flag, "AnyEvent::Base::CondVar"	1288	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
642	}
643
644	sub AnyEvent::Base::CondVar::broadcast {
645	${$_[0]}++;
646	}
647
648	sub AnyEvent::Base::CondVar::wait {
649	AnyEvent->one_event while !${$_[0]};
650	}	1289	}
651		1290
652	# default implementation for ->signal	1291	# default implementation for ->signal
653		1292
654	our %SIG_CB;	1293	our $HAVE_ASYNC_INTERRUPT;
655		1294
		1295	sub _have_async_interrupt() {
		1296	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1297	&& eval "use Async::Interrupt 1.0 (); 1")
		1298	unless defined $HAVE_ASYNC_INTERRUPT;
		1299
		1300	$HAVE_ASYNC_INTERRUPT
		1301	}
		1302
		1303	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1304	our (%SIG_ASY, %SIG_ASY_W);
		1305	our ($SIG_COUNT, $SIG_TW);
		1306
		1307	sub _signal_exec {
		1308	$HAVE_ASYNC_INTERRUPT
		1309	? $SIGPIPE_R->drain
		1310	: sysread $SIGPIPE_R, my $dummy, 9;
		1311
		1312	while (%SIG_EV) {
		1313	for (keys %SIG_EV) {
		1314	delete $SIG_EV{$_};
		1315	$_->() for values %{ $SIG_CB{$_} || {} };
		1316	}
		1317	}
		1318	}
		1319
		1320	# install a dummy wakeup watcher to reduce signal catching latency
		1321	sub _sig_add() {
		1322	unless ($SIG_COUNT++) {
		1323	# try to align timer on a full-second boundary, if possible
		1324	my $NOW = AnyEvent->now;
		1325
		1326	$SIG_TW = AnyEvent->timer (
		1327	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1328	interval => $MAX_SIGNAL_LATENCY,
		1329	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1330	);
		1331	}
		1332	}
		1333
		1334	sub _sig_del {
		1335	undef $SIG_TW
		1336	unless --$SIG_COUNT;
		1337	}
		1338
		1339	our $_sig_name_init; $_sig_name_init = sub {
		1340	undef $_sig_name_init;
		1341
		1342	if (_have_async_interrupt) {
		1343	*sig2num = \&Async::Interrupt::sig2num;
		1344	*sig2name = \&Async::Interrupt::sig2name;
		1345	} else {
		1346	require Config;
		1347
		1348	my %signame2num;
		1349	@signame2num{ split ' ', $Config::Config{sig_name} }
		1350	= split ' ', $Config::Config{sig_num};
		1351
		1352	my @signum2name;
		1353	@signum2name[values %signame2num] = keys %signame2num;
		1354
		1355	*sig2num = sub($) {
		1356	$_[0] > 0 ? shift : $signame2num{+shift}
		1357	};
		1358	*sig2name = sub ($) {
		1359	$_[0] > 0 ? $signum2name[+shift] : shift
		1360	};
		1361	}
		1362	};
		1363
		1364	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1365	sub sig2name($) { &$_sig_name_init; &sig2name }
		1366
656	sub signal {	1367	sub _signal {
657	my (undef, %arg) = @_;	1368	my (undef, %arg) = @_;
658		1369
659	my $signal = uc $arg{signal}	1370	my $signal = uc $arg{signal}
660	or Carp::croak "required option 'signal' is missing";	1371	or Carp::croak "required option 'signal' is missing";
661		1372
		1373	if ($HAVE_ASYNC_INTERRUPT) {
		1374	# async::interrupt
		1375
		1376	$signal = sig2num $signal;
662	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1377	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1378
		1379	$SIG_ASY{$signal} ||= new Async::Interrupt
		1380	cb => sub { undef $SIG_EV{$signal} },
		1381	signal => $signal,
		1382	pipe => [$SIGPIPE_R->filenos],
		1383	pipe_autodrain => 0,
		1384	;
		1385
		1386	} else {
		1387	# pure perl
		1388
		1389	# AE::Util has been loaded in signal
		1390	$signal = sig2name $signal;
		1391	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1392
663	$SIG{$signal} ||= sub {	1393	$SIG{$signal} ||= sub {
664	$_->() for values %{ $SIG_CB{$signal} || {} };	1394	local $!;
		1395	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1396	undef $SIG_EV{$signal};
		1397	};
		1398
		1399	# can't do signal processing without introducing races in pure perl,
		1400	# so limit the signal latency.
		1401	_sig_add;
665	};	1402	}
666		1403
667	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1404	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
668	}	1405	}
669		1406
		1407	sub signal {
		1408	# probe for availability of Async::Interrupt
		1409	if (_have_async_interrupt) {
		1410	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1411
		1412	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1413	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1414
		1415	} else {
		1416	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1417
		1418	require Fcntl;
		1419
		1420	if (AnyEvent::WIN32) {
		1421	require AnyEvent::Util;
		1422
		1423	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1424	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1425	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1426	} else {
		1427	pipe $SIGPIPE_R, $SIGPIPE_W;
		1428	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1429	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1430
		1431	# not strictly required, as $^F is normally 2, but let's make sure...
		1432	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1433	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1434	}
		1435
		1436	$SIGPIPE_R
		1437	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1438
		1439	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1440	}
		1441
		1442	*signal = \&_signal;
		1443	&signal
		1444	}
		1445
670	sub AnyEvent::Base::Signal::DESTROY {	1446	sub AnyEvent::Base::signal::DESTROY {
671	my ($signal, $cb) = @{$_[0]};	1447	my ($signal, $cb) = @{$_[0]};
672		1448
		1449	_sig_del;
		1450
673	delete $SIG_CB{$signal}{$cb};	1451	delete $SIG_CB{$signal}{$cb};
674		1452
675	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1453	$HAVE_ASYNC_INTERRUPT
		1454	? delete $SIG_ASY{$signal}
		1455	: # delete doesn't work with older perls - they then
		1456	# print weird messages, or just unconditionally exit
		1457	# instead of getting the default action.
		1458	undef $SIG{$signal}
		1459	unless keys %{ $SIG_CB{$signal} };
676	}	1460	}
677		1461
678	# default implementation for ->child	1462	# default implementation for ->child
679		1463
680	our %PID_CB;	1464	our %PID_CB;
681	our $CHLD_W;	1465	our $CHLD_W;
682	our $CHLD_DELAY_W;	1466	our $CHLD_DELAY_W;
683	our $PID_IDLE;
684	our $WNOHANG;	1467	our $WNOHANG;
685		1468
686	sub _child_wait {	1469	sub _emit_childstatus($$) {
687	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1470	my (undef, $rpid, $rstatus) = @_;
		1471
		1472	$_->($rpid, $rstatus)
688	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1473	for values %{ $PID_CB{$rpid} || {} },
689	(values %{ $PID_CB{0} || {} });	1474	values %{ $PID_CB{0} || {} };
690	}
691
692	undef $PID_IDLE;
693	}	1475	}
694		1476
695	sub _sigchld {	1477	sub _sigchld {
696	# make sure we deliver these changes "synchronous" with the event loop.	1478	my $pid;
697	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1479
698	undef $CHLD_DELAY_W;	1480	AnyEvent->_emit_childstatus ($pid, $?)
699	&_child_wait;	1481	while ($pid = waitpid -1, $WNOHANG) > 0;
700	});
701	}	1482	}
702		1483
703	sub child {	1484	sub child {
704	my (undef, %arg) = @_;	1485	my (undef, %arg) = @_;
705		1486
706	defined (my $pid = $arg{pid} + 0)	1487	defined (my $pid = $arg{pid} + 0)
707	or Carp::croak "required option 'pid' is missing";	1488	or Carp::croak "required option 'pid' is missing";
708		1489
709	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1490	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
710		1491
711	unless ($WNOHANG) {	1492	# WNOHANG is almost cetrainly 1 everywhere
712	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;	1493	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
713	}	1494	? 1
		1495	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
714		1496
715	unless ($CHLD_W) {	1497	unless ($CHLD_W) {
716	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1498	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
717	# child could be a zombie already, so make at least one round	1499	# child could be a zombie already, so make at least one round
718	&_sigchld;	1500	&_sigchld;
719	}	1501	}
720		1502
721	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1503	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
722	}	1504	}
723		1505
724	sub AnyEvent::Base::Child::DESTROY {	1506	sub AnyEvent::Base::child::DESTROY {
725	my ($pid, $cb) = @{$_[0]};	1507	my ($pid, $cb) = @{$_[0]};
726		1508
727	delete $PID_CB{$pid}{$cb};	1509	delete $PID_CB{$pid}{$cb};
728	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1510	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
729		1511
730	undef $CHLD_W unless keys %PID_CB;	1512	undef $CHLD_W unless keys %PID_CB;
731	}	1513	}
		1514
		1515	# idle emulation is done by simply using a timer, regardless
		1516	# of whether the process is idle or not, and not letting
		1517	# the callback use more than 50% of the time.
		1518	sub idle {
		1519	my (undef, %arg) = @_;
		1520
		1521	my ($cb, $w, $rcb) = $arg{cb};
		1522
		1523	$rcb = sub {
		1524	if ($cb) {
		1525	$w = _time;
		1526	&$cb;
		1527	$w = _time - $w;
		1528
		1529	# never use more then 50% of the time for the idle watcher,
		1530	# within some limits
		1531	$w = 0.0001 if $w < 0.0001;
		1532	$w = 5 if $w > 5;
		1533
		1534	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1535	} else {
		1536	# clean up...
		1537	undef $w;
		1538	undef $rcb;
		1539	}
		1540	};
		1541
		1542	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1543
		1544	bless \\$cb, "AnyEvent::Base::idle"
		1545	}
		1546
		1547	sub AnyEvent::Base::idle::DESTROY {
		1548	undef $${$_[0]};
		1549	}
		1550
		1551	package AnyEvent::CondVar;
		1552
		1553	our @ISA = AnyEvent::CondVar::Base::;
		1554
		1555	package AnyEvent::CondVar::Base;
		1556
		1557	#use overload
		1558	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1559	# fallback => 1;
		1560
		1561	# save 300+ kilobytes by dirtily hardcoding overloading
		1562	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1563	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1564	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1565	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1566
		1567	our $WAITING;
		1568
		1569	sub _send {
		1570	# nop
		1571	}
		1572
		1573	sub send {
		1574	my $cv = shift;
		1575	$cv->{_ae_sent} = [@_];
		1576	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1577	$cv->_send;
		1578	}
		1579
		1580	sub croak {
		1581	$_[0]{_ae_croak} = $_[1];
		1582	$_[0]->send;
		1583	}
		1584
		1585	sub ready {
		1586	$_[0]{_ae_sent}
		1587	}
		1588
		1589	sub _wait {
		1590	$WAITING
		1591	and !$_[0]{_ae_sent}
		1592	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1593
		1594	local $WAITING = 1;
		1595	AnyEvent->one_event while !$_[0]{_ae_sent};
		1596	}
		1597
		1598	sub recv {
		1599	$_[0]->_wait;
		1600
		1601	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1602	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1603	}
		1604
		1605	sub cb {
		1606	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1607	$_[0]{_ae_cb}
		1608	}
		1609
		1610	sub begin {
		1611	++$_[0]{_ae_counter};
		1612	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1613	}
		1614
		1615	sub end {
		1616	return if --$_[0]{_ae_counter};
		1617	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
		1618	}
		1619
		1620	# undocumented/compatibility with pre-3.4
		1621	*broadcast = \&send;
		1622	*wait = \&_wait;
		1623
		1624	=head1 ERROR AND EXCEPTION HANDLING
		1625
		1626	In general, AnyEvent does not do any error handling - it relies on the
		1627	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1628	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1629	checking of all AnyEvent methods, however, which is highly useful during
		1630	development.
		1631
		1632	As for exception handling (i.e. runtime errors and exceptions thrown while
		1633	executing a callback), this is not only highly event-loop specific, but
		1634	also not in any way wrapped by this module, as this is the job of the main
		1635	program.
		1636
		1637	The pure perl event loop simply re-throws the exception (usually
		1638	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1639	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1640	so on.
		1641
		1642	=head1 ENVIRONMENT VARIABLES
		1643
		1644	The following environment variables are used by this module or its
		1645	submodules.
		1646
		1647	Note that AnyEvent will remove I<all> environment variables starting with
		1648	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1649	enabled.
		1650
		1651	=over 4
		1652
		1653	=item C<PERL_ANYEVENT_VERBOSE>
		1654
		1655	By default, AnyEvent will be completely silent except in fatal
		1656	conditions. You can set this environment variable to make AnyEvent more
		1657	talkative.
		1658
		1659	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1660	conditions, such as not being able to load the event model specified by
		1661	C<PERL_ANYEVENT_MODEL>.
		1662
		1663	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1664	model it chooses.
		1665
		1666	When set to C<8> or higher, then AnyEvent will report extra information on
		1667	which optional modules it loads and how it implements certain features.
		1668
		1669	=item C<PERL_ANYEVENT_STRICT>
		1670
		1671	AnyEvent does not do much argument checking by default, as thorough
		1672	argument checking is very costly. Setting this variable to a true value
		1673	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1674	check the arguments passed to most method calls. If it finds any problems,
		1675	it will croak.
		1676
		1677	In other words, enables "strict" mode.
		1678
		1679	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
		1680	>>, it is definitely recommended to keep it off in production. Keeping
		1681	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1682	can be very useful, however.
		1683
		1684	=item C<PERL_ANYEVENT_MODEL>
		1685
		1686	This can be used to specify the event model to be used by AnyEvent, before
		1687	auto detection and -probing kicks in. It must be a string consisting
		1688	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1689	and the resulting module name is loaded and if the load was successful,
		1690	used as event model. If it fails to load AnyEvent will proceed with
		1691	auto detection and -probing.
		1692
		1693	This functionality might change in future versions.
		1694
		1695	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1696	could start your program like this:
		1697
		1698	PERL_ANYEVENT_MODEL=Perl perl ...
		1699
		1700	=item C<PERL_ANYEVENT_PROTOCOLS>
		1701
		1702	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1703	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1704	of auto probing).
		1705
		1706	Must be set to a comma-separated list of protocols or address families,
		1707	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1708	used, and preference will be given to protocols mentioned earlier in the
		1709	list.
		1710
		1711	This variable can effectively be used for denial-of-service attacks
		1712	against local programs (e.g. when setuid), although the impact is likely
		1713	small, as the program has to handle conenction and other failures anyways.
		1714
		1715	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1716	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1717	- only support IPv4, never try to resolve or contact IPv6
		1718	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1719	IPv6, but prefer IPv6 over IPv4.
		1720
		1721	=item C<PERL_ANYEVENT_EDNS0>
		1722
		1723	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1724	for DNS. This extension is generally useful to reduce DNS traffic, but
		1725	some (broken) firewalls drop such DNS packets, which is why it is off by
		1726	default.
		1727
		1728	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1729	EDNS0 in its DNS requests.
		1730
		1731	=item C<PERL_ANYEVENT_MAX_FORKS>
		1732
		1733	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1734	will create in parallel.
		1735
		1736	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1737
		1738	The default value for the C<max_outstanding> parameter for the default DNS
		1739	resolver - this is the maximum number of parallel DNS requests that are
		1740	sent to the DNS server.
		1741
		1742	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1743
		1744	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1745	configuration) in the default resolver. When set to the empty string, no
		1746	default config will be used.
		1747
		1748	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1749
		1750	When neither C<ca_file> nor C<ca_path> was specified during
		1751	L<AnyEvent::TLS> context creation, and either of these environment
		1752	variables exist, they will be used to specify CA certificate locations
		1753	instead of a system-dependent default.
		1754
		1755	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1756
		1757	When these are set to C<1>, then the respective modules are not
		1758	loaded. Mostly good for testing AnyEvent itself.
		1759
		1760	=back
732		1761
733	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1762	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
734		1763
735	This is an advanced topic that you do not normally need to use AnyEvent in	1764	This is an advanced topic that you do not normally need to use AnyEvent in
736	a module. This section is only of use to event loop authors who want to	1765	a module. This section is only of use to event loop authors who want to
…		…
770		1799
771	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1800	I<rxvt-unicode> also cheats a bit by not providing blocking access to
772	condition variables: code blocking while waiting for a condition will	1801	condition variables: code blocking while waiting for a condition will
773	C<die>. This still works with most modules/usages, and blocking calls must	1802	C<die>. This still works with most modules/usages, and blocking calls must
774	not be done in an interactive application, so it makes sense.	1803	not be done in an interactive application, so it makes sense.
775
776	=head1 ENVIRONMENT VARIABLES
777
778	The following environment variables are used by this module:
779
780	=over 4
781
782	=item C<PERL_ANYEVENT_VERBOSE>
783
784	By default, AnyEvent will be completely silent except in fatal
785	conditions. You can set this environment variable to make AnyEvent more
786	talkative.
787
788	When set to C<1> or higher, causes AnyEvent to warn about unexpected
789	conditions, such as not being able to load the event model specified by
790	C<PERL_ANYEVENT_MODEL>.
791
792	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
793	model it chooses.
794
795	=item C<PERL_ANYEVENT_MODEL>
796
797	This can be used to specify the event model to be used by AnyEvent, before
798	autodetection and -probing kicks in. It must be a string consisting
799	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
800	and the resulting module name is loaded and if the load was successful,
801	used as event model. If it fails to load AnyEvent will proceed with
802	autodetection and -probing.
803
804	This functionality might change in future versions.
805
806	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
807	could start your program like this:
808
809	PERL_ANYEVENT_MODEL=Perl perl ...
810
811	=back
812		1804
813	=head1 EXAMPLE PROGRAM	1805	=head1 EXAMPLE PROGRAM
814		1806
815	The following program uses an I/O watcher to read data from STDIN, a timer	1807	The following program uses an I/O watcher to read data from STDIN, a timer
816	to display a message once per second, and a condition variable to quit the	1808	to display a message once per second, and a condition variable to quit the
…		…
825	poll => 'r',	1817	poll => 'r',
826	cb => sub {	1818	cb => sub {
827	warn "io event <$_[0]>\n"; # will always output <r>	1819	warn "io event <$_[0]>\n"; # will always output <r>
828	chomp (my $input = <STDIN>); # read a line	1820	chomp (my $input = <STDIN>); # read a line
829	warn "read: $input\n"; # output what has been read	1821	warn "read: $input\n"; # output what has been read
830	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1822	$cv->send if $input =~ /^q/i; # quit program if /^q/i
831	},	1823	},
832	);	1824	);
833		1825
834	my $time_watcher; # can only be used once	1826	my $time_watcher; # can only be used once
835		1827
…		…
840	});	1832	});
841	}	1833	}
842		1834
843	new_timer; # create first timer	1835	new_timer; # create first timer
844		1836
845	$cv->wait; # wait until user enters /^q/i	1837	$cv->recv; # wait until user enters /^q/i
846		1838
847	=head1 REAL-WORLD EXAMPLE	1839	=head1 REAL-WORLD EXAMPLE
848		1840
849	Consider the L<Net::FCP> module. It features (among others) the following	1841	Consider the L<Net::FCP> module. It features (among others) the following
850	API calls, which are to freenet what HTTP GET requests are to http:	1842	API calls, which are to freenet what HTTP GET requests are to http:
…		…
900	syswrite $txn->{fh}, $txn->{request}	1892	syswrite $txn->{fh}, $txn->{request}
901	or die "connection or write error";	1893	or die "connection or write error";
902	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1894	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
903		1895
904	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1896	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
905	result and signals any possible waiters that the request ahs finished:	1897	result and signals any possible waiters that the request has finished:
906		1898
907	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1899	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
908		1900
909	if (end-of-file or data complete) {	1901	if (end-of-file or data complete) {
910	$txn->{result} = $txn->{buf};	1902	$txn->{result} = $txn->{buf};
911	$txn->{finished}->broadcast;	1903	$txn->{finished}->send;
912	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1904	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
913	}	1905	}
914		1906
915	The C<result> method, finally, just waits for the finished signal (if the	1907	The C<result> method, finally, just waits for the finished signal (if the
916	request was already finished, it doesn't wait, of course, and returns the	1908	request was already finished, it doesn't wait, of course, and returns the
917	data:	1909	data:
918		1910
919	$txn->{finished}->wait;	1911	$txn->{finished}->recv;
920	return $txn->{result};	1912	return $txn->{result};
921		1913
922	The actual code goes further and collects all errors (C<die>s, exceptions)	1914	The actual code goes further and collects all errors (C<die>s, exceptions)
923	that occured during request processing. The C<result> method detects	1915	that occurred during request processing. The C<result> method detects
924	whether an exception as thrown (it is stored inside the $txn object)	1916	whether an exception as thrown (it is stored inside the $txn object)
925	and just throws the exception, which means connection errors and other	1917	and just throws the exception, which means connection errors and other
926	problems get reported tot he code that tries to use the result, not in a	1918	problems get reported tot he code that tries to use the result, not in a
927	random callback.	1919	random callback.
928		1920
…		…
959		1951
960	my $quit = AnyEvent->condvar;	1952	my $quit = AnyEvent->condvar;
961		1953
962	$fcp->txn_client_get ($url)->cb (sub {	1954	$fcp->txn_client_get ($url)->cb (sub {
963	...	1955	...
964	$quit->broadcast;	1956	$quit->send;
965	});	1957	});
966		1958
967	$quit->wait;	1959	$quit->recv;
968		1960
969		1961
970	=head1 BENCHMARKS	1962	=head1 BENCHMARKS
971		1963
972	To give you an idea of the performance and overheads that AnyEvent adds	1964	To give you an idea of the performance and overheads that AnyEvent adds
…		…
974	of various event loops I prepared some benchmarks.	1966	of various event loops I prepared some benchmarks.
975		1967
976	=head2 BENCHMARKING ANYEVENT OVERHEAD	1968	=head2 BENCHMARKING ANYEVENT OVERHEAD
977		1969
978	Here is a benchmark of various supported event models used natively and	1970	Here is a benchmark of various supported event models used natively and
979	through anyevent. The benchmark creates a lot of timers (with a zero	1971	through AnyEvent. The benchmark creates a lot of timers (with a zero
980	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1972	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
981	which it is), lets them fire exactly once and destroys them again.	1973	which it is), lets them fire exactly once and destroys them again.
982		1974
983	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1975	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
984	distribution.	1976	distribution.
…		…
1001	all watchers, to avoid adding memory overhead. That means closure creation	1993	all watchers, to avoid adding memory overhead. That means closure creation
1002	and memory usage is not included in the figures.	1994	and memory usage is not included in the figures.
1003		1995
1004	I<invoke> is the time, in microseconds, used to invoke a simple	1996	I<invoke> is the time, in microseconds, used to invoke a simple
1005	callback. The callback simply counts down a Perl variable and after it was	1997	callback. The callback simply counts down a Perl variable and after it was
1006	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1998	invoked "watcher" times, it would C<< ->send >> a condvar once to
1007	signal the end of this phase.	1999	signal the end of this phase.
1008		2000
1009	I<destroy> is the time, in microseconds, that it takes to destroy a single	2001	I<destroy> is the time, in microseconds, that it takes to destroy a single
1010	watcher.	2002	watcher.
1011		2003
1012	=head3 Results	2004	=head3 Results
1013		2005
1014	name watchers bytes create invoke destroy comment	2006	name watchers bytes create invoke destroy comment
1015	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	2007	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1016	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	2008	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1017	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	2009	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1018	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	2010	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1019	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	2011	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1020	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	2012	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		2013	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		2014	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1021	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	2015	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1022	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	2016	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1023	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	2017	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1024	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	2018	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1025		2019
1026	=head3 Discussion	2020	=head3 Discussion
1027		2021
1028	The benchmark does I<not> measure scalability of the event loop very	2022	The benchmark does I<not> measure scalability of the event loop very
1029	well. For example, a select-based event loop (such as the pure perl one)	2023	well. For example, a select-based event loop (such as the pure perl one)
…		…
1054	performance becomes really bad with lots of file descriptors (and few of	2048	performance becomes really bad with lots of file descriptors (and few of
1055	them active), of course, but this was not subject of this benchmark.	2049	them active), of course, but this was not subject of this benchmark.
1056		2050
1057	The C<Event> module has a relatively high setup and callback invocation	2051	The C<Event> module has a relatively high setup and callback invocation
1058	cost, but overall scores in on the third place.	2052	cost, but overall scores in on the third place.
		2053
		2054	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2055	when using its pure perl backend.
1059		2056
1060	C<Glib>'s memory usage is quite a bit higher, but it features a	2057	C<Glib>'s memory usage is quite a bit higher, but it features a
1061	faster callback invocation and overall ends up in the same class as	2058	faster callback invocation and overall ends up in the same class as
1062	C<Event>. However, Glib scales extremely badly, doubling the number of	2059	C<Event>. However, Glib scales extremely badly, doubling the number of
1063	watchers increases the processing time by more than a factor of four,	2060	watchers increases the processing time by more than a factor of four,
…		…
1107		2104
1108	=back	2105	=back
1109		2106
1110	=head2 BENCHMARKING THE LARGE SERVER CASE	2107	=head2 BENCHMARKING THE LARGE SERVER CASE
1111		2108
1112	This benchmark atcually benchmarks the event loop itself. It works by	2109	This benchmark actually benchmarks the event loop itself. It works by
1113	creating a number of "servers": each server consists of a socketpair, a	2110	creating a number of "servers": each server consists of a socket pair, a
1114	timeout watcher that gets reset on activity (but never fires), and an I/O	2111	timeout watcher that gets reset on activity (but never fires), and an I/O
1115	watcher waiting for input on one side of the socket. Each time the socket	2112	watcher waiting for input on one side of the socket. Each time the socket
1116	watcher reads a byte it will write that byte to a random other "server".	2113	watcher reads a byte it will write that byte to a random other "server".
1117		2114
1118	The effect is that there will be a lot of I/O watchers, only part of which	2115	The effect is that there will be a lot of I/O watchers, only part of which
1119	are active at any one point (so there is a constant number of active	2116	are active at any one point (so there is a constant number of active
1120	fds for each loop iterstaion, but which fds these are is random). The	2117	fds for each loop iteration, but which fds these are is random). The
1121	timeout is reset each time something is read because that reflects how	2118	timeout is reset each time something is read because that reflects how
1122	most timeouts work (and puts extra pressure on the event loops).	2119	most timeouts work (and puts extra pressure on the event loops).
1123		2120
1124	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	2121	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1125	(1%) are active. This mirrors the activity of large servers with many	2122	(1%) are active. This mirrors the activity of large servers with many
1126	connections, most of which are idle at any one point in time.	2123	connections, most of which are idle at any one point in time.
1127		2124
1128	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2125	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1129	distribution.	2126	distribution.
…		…
1131	=head3 Explanation of the columns	2128	=head3 Explanation of the columns
1132		2129
1133	I<sockets> is the number of sockets, and twice the number of "servers" (as	2130	I<sockets> is the number of sockets, and twice the number of "servers" (as
1134	each server has a read and write socket end).	2131	each server has a read and write socket end).
1135		2132
1136	I<create> is the time it takes to create a socketpair (which is	2133	I<create> is the time it takes to create a socket pair (which is
1137	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	2134	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1138		2135
1139	I<request>, the most important value, is the time it takes to handle a	2136	I<request>, the most important value, is the time it takes to handle a
1140	single "request", that is, reading the token from the pipe and forwarding	2137	single "request", that is, reading the token from the pipe and forwarding
1141	it to another server. This includes deleting the old timeout and creating	2138	it to another server. This includes deleting the old timeout and creating
1142	a new one that moves the timeout into the future.	2139	a new one that moves the timeout into the future.
1143		2140
1144	=head3 Results	2141	=head3 Results
1145		2142
1146	name sockets create request	2143	name sockets create request
1147	EV 20000 69.01 11.16	2144	EV 20000 69.01 11.16
1148	Perl 20000 73.32 35.87	2145	Perl 20000 73.32 35.87
		2146	IOAsync 20000 157.00 98.14 epoll
		2147	IOAsync 20000 159.31 616.06 poll
1149	Event 20000 212.62 257.32	2148	Event 20000 212.62 257.32
1150	Glib 20000 651.16 1896.30	2149	Glib 20000 651.16 1896.30
1151	POE 20000 349.67 12317.24 uses POE::Loop::Event	2150	POE 20000 349.67 12317.24 uses POE::Loop::Event
1152		2151
1153	=head3 Discussion	2152	=head3 Discussion
1154		2153
1155	This benchmark I<does> measure scalability and overall performance of the	2154	This benchmark I<does> measure scalability and overall performance of the
1156	particular event loop.	2155	particular event loop.
…		…
1158	EV is again fastest. Since it is using epoll on my system, the setup time	2157	EV is again fastest. Since it is using epoll on my system, the setup time
1159	is relatively high, though.	2158	is relatively high, though.
1160		2159
1161	Perl surprisingly comes second. It is much faster than the C-based event	2160	Perl surprisingly comes second. It is much faster than the C-based event
1162	loops Event and Glib.	2161	loops Event and Glib.
		2162
		2163	IO::Async performs very well when using its epoll backend, and still quite
		2164	good compared to Glib when using its pure perl backend.
1163		2165
1164	Event suffers from high setup time as well (look at its code and you will	2166	Event suffers from high setup time as well (look at its code and you will
1165	understand why). Callback invocation also has a high overhead compared to	2167	understand why). Callback invocation also has a high overhead compared to
1166	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2168	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1167	uses select or poll in basically all documented configurations.	2169	uses select or poll in basically all documented configurations.
…		…
1214	speed most when you have lots of watchers, not when you only have a few of	2216	speed most when you have lots of watchers, not when you only have a few of
1215	them).	2217	them).
1216		2218
1217	EV is again fastest.	2219	EV is again fastest.
1218		2220
1219	Perl again comes second. It is noticably faster than the C-based event	2221	Perl again comes second. It is noticeably faster than the C-based event
1220	loops Event and Glib, although the difference is too small to really	2222	loops Event and Glib, although the difference is too small to really
1221	matter.	2223	matter.
1222		2224
1223	POE also performs much better in this case, but is is still far behind the	2225	POE also performs much better in this case, but is is still far behind the
1224	others.	2226	others.
…		…
1230	=item * C-based event loops perform very well with small number of	2232	=item * C-based event loops perform very well with small number of
1231	watchers, as the management overhead dominates.	2233	watchers, as the management overhead dominates.
1232		2234
1233	=back	2235	=back
1234		2236
		2237	=head2 THE IO::Lambda BENCHMARK
		2238
		2239	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2240	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2241	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2242	shouldn't come as a surprise to anybody). As such, the benchmark is
		2243	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2244	very optimal. But how would AnyEvent compare when used without the extra
		2245	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2246
		2247	The benchmark itself creates an echo-server, and then, for 500 times,
		2248	connects to the echo server, sends a line, waits for the reply, and then
		2249	creates the next connection. This is a rather bad benchmark, as it doesn't
		2250	test the efficiency of the framework or much non-blocking I/O, but it is a
		2251	benchmark nevertheless.
		2252
		2253	name runtime
		2254	Lambda/select 0.330 sec
		2255	+ optimized 0.122 sec
		2256	Lambda/AnyEvent 0.327 sec
		2257	+ optimized 0.138 sec
		2258	Raw sockets/select 0.077 sec
		2259	POE/select, components 0.662 sec
		2260	POE/select, raw sockets 0.226 sec
		2261	POE/select, optimized 0.404 sec
		2262
		2263	AnyEvent/select/nb 0.085 sec
		2264	AnyEvent/EV/nb 0.068 sec
		2265	+state machine 0.134 sec
		2266
		2267	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2268	benchmarks actually make blocking connects and use 100% blocking I/O,
		2269	defeating the purpose of an event-based solution. All of the newly
		2270	written AnyEvent benchmarks use 100% non-blocking connects (using
		2271	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2272	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2273	generally require a lot more bookkeeping and event handling than blocking
		2274	connects (which involve a single syscall only).
		2275
		2276	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2277	offers similar expressive power as POE and IO::Lambda, using conventional
		2278	Perl syntax. This means that both the echo server and the client are 100%
		2279	non-blocking, further placing it at a disadvantage.
		2280
		2281	As you can see, the AnyEvent + EV combination even beats the
		2282	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2283	backend easily beats IO::Lambda and POE.
		2284
		2285	And even the 100% non-blocking version written using the high-level (and
		2286	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2287	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2288	in a non-blocking way.
		2289
		2290	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2291	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2292	part of the IO::lambda distribution and were used without any changes.
		2293
		2294
		2295	=head1 SIGNALS
		2296
		2297	AnyEvent currently installs handlers for these signals:
		2298
		2299	=over 4
		2300
		2301	=item SIGCHLD
		2302
		2303	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2304	emulation for event loops that do not support them natively. Also, some
		2305	event loops install a similar handler.
		2306
		2307	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2308	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2309
		2310	=item SIGPIPE
		2311
		2312	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2313	when AnyEvent gets loaded.
		2314
		2315	The rationale for this is that AnyEvent users usually do not really depend
		2316	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2317	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2318	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2319	some random socket.
		2320
		2321	The rationale for installing a no-op handler as opposed to ignoring it is
		2322	that this way, the handler will be restored to defaults on exec.
		2323
		2324	Feel free to install your own handler, or reset it to defaults.
		2325
		2326	=back
		2327
		2328	=cut
		2329
		2330	undef $SIG{CHLD}
		2331	if $SIG{CHLD} eq 'IGNORE';
		2332
		2333	$SIG{PIPE} = sub { }
		2334	unless defined $SIG{PIPE};
		2335
		2336	=head1 RECOMMENDED/OPTIONAL MODULES
		2337
		2338	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2339	it's built-in modules) are required to use it.
		2340
		2341	That does not mean that AnyEvent won't take advantage of some additional
		2342	modules if they are installed.
		2343
		2344	This section epxlains which additional modules will be used, and how they
		2345	affect AnyEvent's operetion.
		2346
		2347	=over 4
		2348
		2349	=item L<Async::Interrupt>
		2350
		2351	This slightly arcane module is used to implement fast signal handling: To
		2352	my knowledge, there is no way to do completely race-free and quick
		2353	signal handling in pure perl. To ensure that signals still get
		2354	delivered, AnyEvent will start an interval timer to wake up perl (and
		2355	catch the signals) with some delay (default is 10 seconds, look for
		2356	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2357
		2358	If this module is available, then it will be used to implement signal
		2359	catching, which means that signals will not be delayed, and the event loop
		2360	will not be interrupted regularly, which is more efficient (And good for
		2361	battery life on laptops).
		2362
		2363	This affects not just the pure-perl event loop, but also other event loops
		2364	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2365
		2366	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2367	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2368	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2369	does nothing for those backends.
		2370
		2371	=item L<EV>
		2372
		2373	This module isn't really "optional", as it is simply one of the backend
		2374	event loops that AnyEvent can use. However, it is simply the best event
		2375	loop available in terms of features, speed and stability: It supports
		2376	the AnyEvent API optimally, implements all the watcher types in XS, does
		2377	automatic timer adjustments even when no monotonic clock is available,
		2378	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2379	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2380	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2381
		2382	=item L<Guard>
		2383
		2384	The guard module, when used, will be used to implement
		2385	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2386	lot less memory), but otherwise doesn't affect guard operation much. It is
		2387	purely used for performance.
		2388
		2389	=item L<JSON> and L<JSON::XS>
		2390
		2391	This module is required when you want to read or write JSON data via
		2392	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2393	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2394
		2395	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2396	installed.
		2397
		2398	=item L<Net::SSLeay>
		2399
		2400	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2401	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2402	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2403
		2404	=item L<Time::HiRes>
		2405
		2406	This module is part of perl since release 5.008. It will be used when the
		2407	chosen event library does not come with a timing source on it's own. The
		2408	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2409	try to use a monotonic clock for timing stability.
		2410
		2411	=back
		2412
1235		2413
1236	=head1 FORK	2414	=head1 FORK
1237		2415
1238	Most event libraries are not fork-safe. The ones who are usually are	2416	Most event libraries are not fork-safe. The ones who are usually are
1239	because they are so inefficient. Only L<EV> is fully fork-aware.	2417	because they rely on inefficient but fork-safe C<select> or C<poll>
		2418	calls. Only L<EV> is fully fork-aware.
1240		2419
1241	If you have to fork, you must either do so I<before> creating your first	2420	If you have to fork, you must either do so I<before> creating your first
1242	watcher OR you must not use AnyEvent at all in the child.	2421	watcher OR you must not use AnyEvent at all in the child OR you must do
		2422	something completely out of the scope of AnyEvent.
1243		2423
1244		2424
1245	=head1 SECURITY CONSIDERATIONS	2425	=head1 SECURITY CONSIDERATIONS
1246		2426
1247	AnyEvent can be forced to load any event model via	2427	AnyEvent can be forced to load any event model via
…		…
1252	specified in the variable.	2432	specified in the variable.
1253		2433
1254	You can make AnyEvent completely ignore this variable by deleting it	2434	You can make AnyEvent completely ignore this variable by deleting it
1255	before the first watcher gets created, e.g. with a C<BEGIN> block:	2435	before the first watcher gets created, e.g. with a C<BEGIN> block:
1256		2436
1257	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	2437	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1258		2438
1259	use AnyEvent;	2439	use AnyEvent;
		2440
		2441	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		2442	be used to probe what backend is used and gain other information (which is
		2443	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		2444	$ENV{PERL_ANYEVENT_STRICT}.
		2445
		2446	Note that AnyEvent will remove I<all> environment variables starting with
		2447	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2448	enabled.
		2449
		2450
		2451	=head1 BUGS
		2452
		2453	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		2454	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		2455	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		2456	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		2457	pronounced).
1260		2458
1261		2459
1262	=head1 SEE ALSO	2460	=head1 SEE ALSO
1263		2461
1264	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	2462	Utility functions: L<AnyEvent::Util>.
1265	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	2463
		2464	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1266	L<Event::Lib>, L<Qt>, L<POE>.	2465	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1267		2466
1268	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	2467	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
		2468	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
		2469	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1269	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	2470	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1270	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,
1271	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.
1272		2471
		2472	Non-blocking file handles, sockets, TCP clients and
		2473	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
		2474
		2475	Asynchronous DNS: L<AnyEvent::DNS>.
		2476
		2477	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2478	L<Coro::Event>,
		2479
1273	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	2480	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2481	L<AnyEvent::HTTP>.
1274		2482
1275		2483
1276	=head1 AUTHOR	2484	=head1 AUTHOR
1277		2485
1278	Marc Lehmann <schmorp@schmorp.de>	2486	Marc Lehmann <schmorp@schmorp.de>
1279	http://home.schmorp.de/	2487	http://home.schmorp.de/
1280		2488
1281	=cut	2489	=cut
1282		2490
1283	1	2491	1
1284		2492

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines