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Revision 1.409 by root, Thu Dec 6 12:10:09 2012 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, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6	event loops.	6	FLTK and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
142	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
177		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331	account.	357	account.
332		358
333	=item AnyEvent->now_update	359	=item AnyEvent->now_update
334		360
335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
336	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
337	AnyEvent->now >>, above).	363	above).
338		364
339	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
340	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
		432	attaching callbacks to signals in a generic way, which is a pity,
		433	as you cannot do race-free signal handling in perl, requiring
		434	C libraries for this. AnyEvent will try to do its best, which
		435	means in some cases, signals will be delayed. The maximum time
		436	a signal might be delayed is 10 seconds by default, but can
		437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
		438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
		439	section for details.
		440
		441	All these problems can be avoided by installing the optional
		442	L<Async::Interrupt> module, which works with most event loops. It will not
		443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		444	(and not with L<POE> currently). For those, you just have to suffer the
		445	delays.
		446
375	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
376		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
377	You can also watch on a child process exit and catch its exit status.	451	You can also watch for a child process exit and catch its exit status.
378		452
379	The child process is specified by the C<pid> argument (if set to C<0>, it	453	The child process is specified by the C<pid> argument (on some backends,
380	watches for any child process exit). The watcher will triggered only when	454	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	455	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	456	finished and an exit status is available, not on any trace events
		457	(stopped/continued).
383		458
384	The callback will be called with the pid and exit status (as returned by	459	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	460	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	461	callback arguments.
387		462
…		…
403		478
404	This means you cannot create a child watcher as the very first	479	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	480	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	481	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	482	C<AnyEvent::detect>).
		483
		484	As most event loops do not support waiting for child events, they will be
		485	emulated by AnyEvent in most cases, in which case the latency and race
		486	problems mentioned in the description of signal watchers apply.
408		487
409	Example: fork a process and wait for it	488	Example: fork a process and wait for it
410		489
411	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
412		491
…		…
424	# do something else, then wait for process exit	503	# do something else, then wait for process exit
425	$done->recv;	504	$done->recv;
426		505
427	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
428		507
429	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		509
434	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	511	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		512
438	Most event loops unfortunately do not really support idle watchers (only	513	Idle watchers are useful when there is a need to do something, but it
		514	is not so important (or wise) to do it instantly. The callback will be
		515	invoked only when there is "nothing better to do", which is usually
		516	defined as "all outstanding events have been handled and no new events
		517	have been detected". That means that idle watchers ideally get invoked
		518	when the event loop has just polled for new events but none have been
		519	detected. Instead of blocking to wait for more events, the idle watchers
		520	will be invoked.
		521
		522	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
441		525
442	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	527	program is otherwise idle:
…		…
459	});	543	});
460	});	544	});
461		545
462	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
463		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
464	If you are familiar with some event loops you will know that all of them	553	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	554	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
467		556
468	AnyEvent is different, it expects somebody else to run the event loop and	557	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	558	loop and will only block when necessary (usually when told by the user).
470		559
471	The instrument to do that is called a "condition variable", so called	560	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	561	they represent a condition that must become true.
		562
		563	Now is probably a good time to look at the examples further below.
473		564
474	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	567	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	568	becomes true, with the condition variable as the first argument (but not
479	the results).	569	the results).
480		570
481	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
482	by calling the C<send> method (or calling the condition variable as if it	572	by calling the C<send> method (or calling the condition variable as if it
483	were a callback, read about the caveats in the description for the C<<	573	were a callback, read about the caveats in the description for the C<<
484	->send >> method).	574	->send >> method).
485		575
486	Condition variables are similar to callbacks, except that you can	576	Since condition variables are the most complex part of the AnyEvent API, here are
487	optionally wait for them. They can also be called merge points - points	577	some different mental models of what they are - pick the ones you can connect to:
488	in time where multiple outstanding events have been processed. And yet	578
489	another way to call them is transactions - each condition variable can be	579	=over 4
490	used to represent a transaction, which finishes at some point and delivers	580
491	a result.	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
		582	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		583
		584	=item * Condition variables are signals - one side can emit or send them,
		585	the other side can wait for them, or install a handler that is called when
		586	the signal fires.
		587
		588	=item * Condition variables are like "Merge Points" - points in your program
		589	where you merge multiple independent results/control flows into one.
		590
		591	=item * Condition variables represent a transaction - functions that start
		592	some kind of transaction can return them, leaving the caller the choice
		593	between waiting in a blocking fashion, or setting a callback.
		594
		595	=item * Condition variables represent future values, or promises to deliver
		596	some result, long before the result is available.
		597
		598	=back
492		599
493	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	601	for example, if you write a module that does asynchronous http requests,
495	then a condition variable would be the ideal candidate to signal the	602	then a condition variable would be the ideal candidate to signal the
496	availability of results. The user can either act when the callback is	603	availability of results. The user can either act when the callback is
…		…
509		616
510	Condition variables are represented by hash refs in perl, and the keys	617	Condition variables are represented by hash refs in perl, and the keys
511	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	618	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
512	easy (it is often useful to build your own transaction class on top of	619	easy (it is often useful to build your own transaction class on top of
513	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	620	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
514	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
515		622
516	There are two "sides" to a condition variable - the "producer side" which	623	There are two "sides" to a condition variable - the "producer side" which
517	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	625	for the send to occur.
519		626
520	Example: wait for a timer.	627	Example: wait for a timer.
521		628
522	# wait till the result is ready	629	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
524		631
525	# do something such as adding a timer	632	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
527	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
530	after => 1,	637	after => 1,
531	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
532	);	639	);
533		640
534	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
535	# calls send	642	# calls ->send
536	$result_ready->recv;	643	$timer_fired->recv;
537		644
538	Example: wait for a timer, but take advantage of the fact that	645	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	646	variables are also callable directly.
540		647
541	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	649	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	650	$done->recv;
544		651
…		…
550		657
551	...	658	...
552		659
553	my @info = $couchdb->info->recv;	660	my @info = $couchdb->info->recv;
554		661
555	And this is how you would just ste a callback to be called whenever the	662	And this is how you would just set a callback to be called whenever the
556	results are available:	663	results are available:
557		664
558	$couchdb->info->cb (sub {	665	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	666	my @info = $_[0]->recv;
560	});	667	});
…		…
578	immediately from within send.	685	immediately from within send.
579		686
580	Any arguments passed to the C<send> call will be returned by all	687	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	688	future C<< ->recv >> calls.
582		689
583	Condition variables are overloaded so one can call them directly	690	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	691	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	692	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		693
592	=item $cv->croak ($error)	694	=item $cv->croak ($error)
593		695
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	696	Similar to send, but causes all calls to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
596		698
597	This can be used to signal any errors to the condition variable	699	This can be used to signal any errors to the condition variable
598	user/consumer.	700	user/consumer. Doing it this way instead of calling C<croak> directly
		701	delays the error detection, but has the overwhelming advantage that it
		702	diagnoses the error at the place where the result is expected, and not
		703	deep in some event callback with no connection to the actual code causing
		704	the problem.
599		705
600	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
601		707
602	=item $cv->end	708	=item $cv->end
603		709
…		…
605	one. For example, a function that pings many hosts in parallel might want	711	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
607		713
608	Every call to C<< ->begin >> will increment a counter, and every call to	714	Every call to C<< ->begin >> will increment a counter, and every call to
609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	715	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
610	>>, the (last) callback passed to C<begin> will be executed. That callback	716	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	717	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	718	>>, but that is not required. If no group callback was set, C<send> will
		719	be called without any arguments.
613		720
614	You can think of C<< $cv->send >> giving you an OR condition (one call	721	You can think of C<< $cv->send >> giving you an OR condition (one call
615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	722	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	723	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		724
…		…
639	one call to C<begin>, so the condvar waits for all calls to C<end> before	746	one call to C<begin>, so the condvar waits for all calls to C<end> before
640	sending.	747	sending.
641		748
642	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
643	there are results to be passwd back, and the number of tasks that are	750	there are results to be passwd back, and the number of tasks that are
644	begung can potentially be zero:	751	begun can potentially be zero:
645		752
646	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
647		754
648	my %result;	755	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
650		757
651	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
652	$cv->begin;	759	$cv->begin;
653	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	761	$result{$host} = ...;
…		…
656	};	763	};
657	}	764	}
658		765
659	$cv->end;	766	$cv->end;
660		767
		768	...
		769
		770	my $results = $cv->recv;
		771
661	This code fragment supposedly pings a number of hosts and calls	772	This code fragment supposedly pings a number of hosts and calls
662	C<send> after results for all then have have been gathered - in any	773	C<send> after results for all then have have been gathered - in any
663	order. To achieve this, the code issues a call to C<begin> when it starts	774	order. To achieve this, the code issues a call to C<begin> when it starts
664	each ping request and calls C<end> when it has received some result for	775	each ping request and calls C<end> when it has received some result for
665	it. Since C<begin> and C<end> only maintain a counter, the order in which	776	it. Since C<begin> and C<end> only maintain a counter, the order in which
…		…
670	to be called once the counter reaches C<0>, and second, it ensures that	781	to be called once the counter reaches C<0>, and second, it ensures that
671	C<send> is called even when C<no> hosts are being pinged (the loop	782	C<send> is called even when C<no> hosts are being pinged (the loop
672	doesn't execute once).	783	doesn't execute once).
673		784
674	This is the general pattern when you "fan out" into multiple (but	785	This is the general pattern when you "fan out" into multiple (but
675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	786	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
676	the callback and ensure C<end> is called at least once, and then, for each	787	the callback and ensure C<end> is called at least once, and then, for each
677	subrequest you start, call C<begin> and for each subrequest you finish,	788	subrequest you start, call C<begin> and for each subrequest you finish,
678	call C<end>.	789	call C<end>.
679		790
680	=back	791	=back
…		…
687	=over 4	798	=over 4
688		799
689	=item $cv->recv	800	=item $cv->recv
690		801
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	802	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	803	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	804	normally.
694		805
695	You can only wait once on a condition - additional calls are valid but	806	You can only wait once on a condition - additional calls are valid but
696	will return immediately.	807	will return immediately.
697		808
…		…
699	function will call C<croak>.	810	function will call C<croak>.
700		811
701	In list context, all parameters passed to C<send> will be returned,	812	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	813	in scalar context only the first one will be returned.
703		814
		815	Note that doing a blocking wait in a callback is not supported by any
		816	event loop, that is, recursive invocation of a blocking C<< ->recv >> is
		817	not allowed and the C<recv> call will C<croak> if such a condition is
		818	detected. This requirement can be dropped by relying on L<Coro::AnyEvent>
		819	, which allows you to do a blocking C<< ->recv >> from any thread
		820	that doesn't run the event loop itself. L<Coro::AnyEvent> is loaded
		821	automatically when L<Coro> is used with L<AnyEvent>, so code does not need
		822	to do anything special to take advantage of that: any code that would
		823	normally block your program because it calls C<recv>, be executed in an
		824	C<async> thread instead without blocking other threads.
		825
704	Not all event models support a blocking wait - some die in that case	826	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	827	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	828	using this from a module, never require a blocking wait>. Instead, let the
707	caller decide whether the call will block or not (for example, by coupling	829	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	830	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	831	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	832	while still supporting blocking waits if the caller so desires).
711		833
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	You can ensure that C<< -recv >> never blocks by setting a callback and	834	You can ensure that C<< ->recv >> never blocks by setting a callback and
724	only calling C<< ->recv >> from within that callback (or at a later	835	only calling C<< ->recv >> from within that callback (or at a later
725	time). This will work even when the event loop does not support blocking	836	time). This will work even when the event loop does not support blocking
726	waits otherwise.	837	waits otherwise.
727		838
728	=item $bool = $cv->ready	839	=item $bool = $cv->ready
…		…
734		845
735	This is a mutator function that returns the callback set and optionally	846	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	847	replaces it before doing so.
737		848
738	The callback will be called when the condition becomes "true", i.e. when	849	The callback will be called when the condition becomes "true", i.e. when
739	C<send> or C<croak> are called, with the only argument being the condition	850	C<send> or C<croak> are called, with the only argument being the
740	variable itself. Calling C<recv> inside the callback or at any later time	851	condition variable itself. If the condition is already true, the
741	is guaranteed not to block.	852	callback is called immediately when it is set. Calling C<recv> inside
		853	the callback or at any later time is guaranteed not to block.
742		854
743	=back	855	=back
744		856
		857	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		858
		859	The available backend classes are (every class has its own manpage):
		860
		861	=over 4
		862
		863	=item Backends that are autoprobed when no other event loop can be found.
		864
		865	EV is the preferred backend when no other event loop seems to be in
		866	use. If EV is not installed, then AnyEvent will fall back to its own
		867	pure-perl implementation, which is available everywhere as it comes with
		868	AnyEvent itself.
		869
		870	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		871	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
		872
		873	=item Backends that are transparently being picked up when they are used.
		874
		875	These will be used if they are already loaded when the first watcher
		876	is created, in which case it is assumed that the application is using
		877	them. This means that AnyEvent will automatically pick the right backend
		878	when the main program loads an event module before anything starts to
		879	create watchers. Nothing special needs to be done by the main program.
		880
		881	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		882	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		883	AnyEvent::Impl::Tk based on Tk, very broken.
		884	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		885	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		886	AnyEvent::Impl::Irssi used when running within irssi.
		887	AnyEvent::Impl::IOAsync based on IO::Async.
		888	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		889	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
		890
		891	=item Backends with special needs.
		892
		893	Qt requires the Qt::Application to be instantiated first, but will
		894	otherwise be picked up automatically. As long as the main program
		895	instantiates the application before any AnyEvent watchers are created,
		896	everything should just work.
		897
		898	AnyEvent::Impl::Qt based on Qt.
		899
		900	=item Event loops that are indirectly supported via other backends.
		901
		902	Some event loops can be supported via other modules:
		903
		904	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		905
		906	B<WxWidgets> has no support for watching file handles. However, you can
		907	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		908	polls 20 times per second, which was considered to be too horrible to even
		909	consider for AnyEvent.
		910
		911	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		912	backend, so it can be supported through POE.
		913
		914	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		915	load L<POE> when detecting them, in the hope that POE will pick them up,
		916	in which case everything will be automatic.
		917
		918	=back
		919
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	920	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		921
		922	These are not normally required to use AnyEvent, but can be useful to
		923	write AnyEvent extension modules.
		924
747	=over 4	925	=over 4
748		926
749	=item $AnyEvent::MODEL	927	=item $AnyEvent::MODEL
750		928
751	Contains C<undef> until the first watcher is being created. Then it	929	Contains C<undef> until the first watcher is being created, before the
		930	backend has been autodetected.
		931
752	contains the event model that is being used, which is the name of the	932	Afterwards it contains the event model that is being used, which is the
753	Perl class implementing the model. This class is usually one of the	933	name of the Perl class implementing the model. This class is usually one
754	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	934	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
755	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	935	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		936	will be C<urxvt::anyevent>).
757	The known classes so far are:
758
759	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760	AnyEvent::Impl::Event based on Event, second best choice.
761	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762	AnyEvent::Impl::Glib based on Glib, third-best choice.
763	AnyEvent::Impl::Tk based on Tk, very bad choice.
764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768	# warning, support for IO::Async is only partial, as it is too broken
769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772	There is no support for WxWidgets, as WxWidgets has no support for
773	watching file handles. However, you can use WxWidgets through the
774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775	second, which was considered to be too horrible to even consider for
776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777	it's adaptor.
778
779	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780	autodetecting them.
781		937
782	=item AnyEvent::detect	938	=item AnyEvent::detect
783		939
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	940	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	if necessary. You should only call this function right before you would	941	if necessary. You should only call this function right before you would
786	have created an AnyEvent watcher anyway, that is, as late as possible at	942	have created an AnyEvent watcher anyway, that is, as late as possible at
787	runtime.	943	runtime, and not e.g. during initialisation of your module.
		944
		945	The effect of calling this function is as if a watcher had been created
		946	(specifically, actions that happen "when the first watcher is created"
		947	happen when calling detetc as well).
		948
		949	If you need to do some initialisation before AnyEvent watchers are
		950	created, use C<post_detect>.
788		951
789	=item $guard = AnyEvent::post_detect { BLOCK }	952	=item $guard = AnyEvent::post_detect { BLOCK }
790		953
791	Arranges for the code block to be executed as soon as the event model is	954	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	955	autodetected (or immediately if that has already happened).
		956
		957	The block will be executed I<after> the actual backend has been detected
		958	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		959	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		960	other initialisations - see the sources of L<AnyEvent::Strict> or
		961	L<AnyEvent::AIO> to see how this is used.
		962
		963	The most common usage is to create some global watchers, without forcing
		964	event module detection too early, for example, L<AnyEvent::AIO> creates
		965	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		966	avoid autodetecting the event module at load time.
793		967
794	If called in scalar or list context, then it creates and returns an object	968	If called in scalar or list context, then it creates and returns an object
795	that automatically removes the callback again when it is destroyed. See	969	that automatically removes the callback again when it is destroyed (or
		970	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
796	L<Coro::BDB> for a case where this is useful.	971	a case where this is useful.
		972
		973	Example: Create a watcher for the IO::AIO module and store it in
		974	C<$WATCHER>, but do so only do so after the event loop is initialised.
		975
		976	our WATCHER;
		977
		978	my $guard = AnyEvent::post_detect {
		979	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		980	};
		981
		982	# the ||= is important in case post_detect immediately runs the block,
		983	# as to not clobber the newly-created watcher. assigning both watcher and
		984	# post_detect guard to the same variable has the advantage of users being
		985	# able to just C<undef $WATCHER> if the watcher causes them grief.
		986
		987	$WATCHER ||= $guard;
797		988
798	=item @AnyEvent::post_detect	989	=item @AnyEvent::post_detect
799		990
800	If there are any code references in this array (you can C<push> to it	991	If there are any code references in this array (you can C<push> to it
801	before or after loading AnyEvent), then they will called directly after	992	before or after loading AnyEvent), then they will be called directly
802	the event loop has been chosen.	993	after the event loop has been chosen.
803		994
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	995	You should check C<$AnyEvent::MODEL> before adding to this array, though:
805	if it contains a true value then the event loop has already been detected,	996	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	997	array will be ignored.
807		998
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	999	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		1000	it, as it takes care of these details.
		1001
		1002	This variable is mainly useful for modules that can do something useful
		1003	when AnyEvent is used and thus want to know when it is initialised, but do
		1004	not need to even load it by default. This array provides the means to hook
		1005	into AnyEvent passively, without loading it.
		1006
		1007	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1008	together, you could put this into Coro (this is the actual code used by
		1009	Coro to accomplish this):
		1010
		1011	if (defined $AnyEvent::MODEL) {
		1012	# AnyEvent already initialised, so load Coro::AnyEvent
		1013	require Coro::AnyEvent;
		1014	} else {
		1015	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1016	# as soon as it is
		1017	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1018	}
		1019
		1020	=item AnyEvent::postpone { BLOCK }
		1021
		1022	Arranges for the block to be executed as soon as possible, but not before
		1023	the call itself returns. In practise, the block will be executed just
		1024	before the event loop polls for new events, or shortly afterwards.
		1025
		1026	This function never returns anything (to make the C<return postpone { ...
		1027	}> idiom more useful.
		1028
		1029	To understand the usefulness of this function, consider a function that
		1030	asynchronously does something for you and returns some transaction
		1031	object or guard to let you cancel the operation. For example,
		1032	C<AnyEvent::Socket::tcp_connect>:
		1033
		1034	# start a conenction attempt unless one is active
		1035	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1036	delete $self->{connect_guard};
		1037	...
		1038	};
		1039
		1040	Imagine that this function could instantly call the callback, for
		1041	example, because it detects an obvious error such as a negative port
		1042	number. Invoking the callback before the function returns causes problems
		1043	however: the callback will be called and will try to delete the guard
		1044	object. But since the function hasn't returned yet, there is nothing to
		1045	delete. When the function eventually returns it will assign the guard
		1046	object to C<< $self->{connect_guard} >>, where it will likely never be
		1047	deleted, so the program thinks it is still trying to connect.
		1048
		1049	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1050	callback directly on error:
		1051
		1052	$cb->(undef), return # signal error to callback, BAD!
		1053	if $some_error_condition;
		1054
		1055	It should use C<postpone>:
		1056
		1057	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1058	if $some_error_condition;
		1059
		1060	=item AnyEvent::log $level, $msg[, @args]
		1061
		1062	Log the given C<$msg> at the given C<$level>.
		1063
		1064	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1065	to see whether the message will be logged. If the test succeeds it will
		1066	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1067	the L<AnyEvent::Log> documentation for details.
		1068
		1069	If the test fails it will simply return. Right now this happens when a
		1070	numerical loglevel is used and it is larger than the level specified via
		1071	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1072
		1073	If you want to sprinkle loads of logging calls around your code, consider
		1074	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1075	which can reduce typing, codesize and can reduce the logging overhead
		1076	enourmously.
809		1077
810	=back	1078	=back
811		1079
812	=head1 WHAT TO DO IN A MODULE	1080	=head1 WHAT TO DO IN A MODULE
813		1081
…		…
824	because it will stall the whole program, and the whole point of using	1092	because it will stall the whole program, and the whole point of using
825	events is to stay interactive.	1093	events is to stay interactive.
826		1094
827	It is fine, however, to call C<< ->recv >> when the user of your module	1095	It is fine, however, to call C<< ->recv >> when the user of your module
828	requests it (i.e. if you create a http request object ad have a method	1096	requests it (i.e. if you create a http request object ad have a method
829	called C<results> that returns the results, it should call C<< ->recv >>	1097	called C<results> that returns the results, it may call C<< ->recv >>
830	freely, as the user of your module knows what she is doing. always).	1098	freely, as the user of your module knows what she is doing. Always).
831		1099
832	=head1 WHAT TO DO IN THE MAIN PROGRAM	1100	=head1 WHAT TO DO IN THE MAIN PROGRAM
833		1101
834	There will always be a single main program - the only place that should	1102	There will always be a single main program - the only place that should
835	dictate which event model to use.	1103	dictate which event model to use.
836		1104
837	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1105	If the program is not event-based, it need not do anything special, even
838	do anything special (it does not need to be event-based) and let AnyEvent	1106	when it depends on a module that uses an AnyEvent. If the program itself
839	decide which implementation to chose if some module relies on it.	1107	uses AnyEvent, but does not care which event loop is used, all it needs
		1108	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1109	available loop implementation.
840		1110
841	If the main program relies on a specific event model - for example, in	1111	If the main program relies on a specific event model - for example, in
842	Gtk2 programs you have to rely on the Glib module - you should load the	1112	Gtk2 programs you have to rely on the Glib module - you should load the
843	event module before loading AnyEvent or any module that uses it: generally	1113	event module before loading AnyEvent or any module that uses it: generally
844	speaking, you should load it as early as possible. The reason is that	1114	speaking, you should load it as early as possible. The reason is that
845	modules might create watchers when they are loaded, and AnyEvent will	1115	modules might create watchers when they are loaded, and AnyEvent will
846	decide on the event model to use as soon as it creates watchers, and it	1116	decide on the event model to use as soon as it creates watchers, and it
847	might chose the wrong one unless you load the correct one yourself.	1117	might choose the wrong one unless you load the correct one yourself.
848		1118
849	You can chose to use a pure-perl implementation by loading the	1119	You can chose to use a pure-perl implementation by loading the
850	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1120	C<AnyEvent::Loop> module, which gives you similar behaviour
851	everywhere, but letting AnyEvent chose the model is generally better.	1121	everywhere, but letting AnyEvent chose the model is generally better.
852		1122
853	=head2 MAINLOOP EMULATION	1123	=head2 MAINLOOP EMULATION
854		1124
855	Sometimes (often for short test scripts, or even standalone programs who	1125	Sometimes (often for short test scripts, or even standalone programs who
…		…
868		1138
869		1139
870	=head1 OTHER MODULES	1140	=head1 OTHER MODULES
871		1141
872	The following is a non-exhaustive list of additional modules that use	1142	The following is a non-exhaustive list of additional modules that use
873	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1143	AnyEvent as a client and can therefore be mixed easily with other
874	modules and other event loops in the same program. Some of the modules	1144	AnyEvent modules and other event loops in the same program. Some of the
875	come with AnyEvent, most are available via CPAN.	1145	modules come as part of AnyEvent, the others are available via CPAN (see
		1146	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1147	a longer non-exhaustive list), and the list is heavily biased towards
		1148	modules of the AnyEvent author himself :)
876		1149
877	=over 4	1150	=over 4
878		1151
879	=item L<AnyEvent::Util>	1152	=item L<AnyEvent::Util>
880		1153
881	Contains various utility functions that replace often-used but blocking	1154	Contains various utility functions that replace often-used blocking
882	functions such as C<inet_aton> by event-/callback-based versions.	1155	functions such as C<inet_aton> with event/callback-based versions.
883		1156
884	=item L<AnyEvent::Socket>	1157	=item L<AnyEvent::Socket>
885		1158
886	Provides various utility functions for (internet protocol) sockets,	1159	Provides various utility functions for (internet protocol) sockets,
887	addresses and name resolution. Also functions to create non-blocking tcp	1160	addresses and name resolution. Also functions to create non-blocking tcp
…		…
889		1162
890	=item L<AnyEvent::Handle>	1163	=item L<AnyEvent::Handle>
891		1164
892	Provide read and write buffers, manages watchers for reads and writes,	1165	Provide read and write buffers, manages watchers for reads and writes,
893	supports raw and formatted I/O, I/O queued and fully transparent and	1166	supports raw and formatted I/O, I/O queued and fully transparent and
894	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1167	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
895		1168
896	=item L<AnyEvent::DNS>	1169	=item L<AnyEvent::DNS>
897		1170
898	Provides rich asynchronous DNS resolver capabilities.	1171	Provides rich asynchronous DNS resolver capabilities.
899		1172
		1173	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1174
		1175	Implement event-based interfaces to the protocols of the same name (for
		1176	the curious, IGS is the International Go Server and FCP is the Freenet
		1177	Client Protocol).
		1178
900	=item L<AnyEvent::HTTP>	1179	=item L<AnyEvent::AIO>
901		1180
902	A simple-to-use HTTP library that is capable of making a lot of concurrent	1181	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
903	HTTP requests.	1182	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1183	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1184	file I/O, and much more.
		1185
		1186	=item L<AnyEvent::Filesys::Notify>
		1187
		1188	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1189	path changes (e.g. "watch this directory for new files", "watch this
		1190	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1191	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1192	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1193	fall back to blocking scans at regular intervals transparently on other
		1194	platforms, so it's about as portable as it gets.
		1195
		1196	(I haven't used it myself, but I haven't heard anybody complaining about
		1197	it yet).
		1198
		1199	=item L<AnyEvent::DBI>
		1200
		1201	Executes L<DBI> requests asynchronously in a proxy process for you,
		1202	notifying you in an event-based way when the operation is finished.
904		1203
905	=item L<AnyEvent::HTTPD>	1204	=item L<AnyEvent::HTTPD>
906		1205
907	Provides a simple web application server framework.	1206	A simple embedded webserver.
908		1207
909	=item L<AnyEvent::FastPing>	1208	=item L<AnyEvent::FastPing>
910		1209
911	The fastest ping in the west.	1210	The fastest ping in the west.
912		1211
913	=item L<AnyEvent::DBI>
914
915	Executes L<DBI> requests asynchronously in a proxy process.
916
917	=item L<AnyEvent::AIO>
918
919	Truly asynchronous I/O, should be in the toolbox of every event
920	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
921	together.
922
923	=item L<AnyEvent::BDB>
924
925	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
926	L<BDB> and AnyEvent together.
927
928	=item L<AnyEvent::GPSD>
929
930	A non-blocking interface to gpsd, a daemon delivering GPS information.
931
932	=item L<AnyEvent::IRC>
933
934	AnyEvent based IRC client module family (replacing the older Net::IRC3).
935
936	=item L<AnyEvent::XMPP>
937
938	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
939	Net::XMPP2>.
940
941	=item L<AnyEvent::IGS>
942
943	A non-blocking interface to the Internet Go Server protocol (used by
944	L<App::IGS>).
945
946	=item L<Net::FCP>
947
948	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
949	of AnyEvent.
950
951	=item L<Event::ExecFlow>
952
953	High level API for event-based execution flow control.
954
955	=item L<Coro>	1212	=item L<Coro>
956		1213
957	Has special support for AnyEvent via L<Coro::AnyEvent>.	1214	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1215	to simply invert the flow control - don't call us, we will call you:
		1216
		1217	async {
		1218	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1219	print "5 seconds later!\n";
		1220
		1221	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1222	my $line = <STDIN>; # works for ttys
		1223
		1224	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1225	my ($body, $hdr) = Coro::rouse_wait;
		1226	};
958		1227
959	=back	1228	=back
960		1229
961	=cut	1230	=cut
962		1231
963	package AnyEvent;	1232	package AnyEvent;
964		1233
965	no warnings;	1234	# basically a tuned-down version of common::sense
966	use strict qw(vars subs);	1235	sub common_sense {
		1236	# from common:.sense 3.5
		1237	local $^W;
		1238	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1239	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1240	$^H |= 0x00000600;
		1241	}
967		1242
		1243	BEGIN { AnyEvent::common_sense }
		1244
968	use Carp;	1245	use Carp ();
969		1246
970	our $VERSION = 4.801;	1247	our $VERSION = '7.04';
971	our $MODEL;	1248	our $MODEL;
972
973	our $AUTOLOAD;
974	our @ISA;	1249	our @ISA;
975
976	our @REGISTRY;	1250	our @REGISTRY;
977		1251	our $VERBOSE;
978	our $WIN32;	1252	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1253	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
979		1254
980	BEGIN {	1255	BEGIN {
981	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1256	require "AnyEvent/constants.pl";
		1257
982	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1258	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
983		1259
984	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1260	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
985	if ${^TAINT};	1261	if ${^TAINT};
986	}
987		1262
988	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1263	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1264	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
989		1265
990	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1266	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1267	if ${^TAINT};
991		1268
992	{	1269	# $ENV{PERL_ANYEVENT_xxx} now valid
		1270
		1271	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
		1272
993	my $idx;	1273	my $idx;
994	$PROTOCOL{$_} = ++$idx	1274	$PROTOCOL{$_} = ++$idx
995	for reverse split /\s*,\s*/,	1275	for reverse split /\s*,\s*/,
996	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1276	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
997	}	1277	}
998		1278
		1279	our @post_detect;
		1280
		1281	sub post_detect(&) {
		1282	my ($cb) = @_;
		1283
		1284	push @post_detect, $cb;
		1285
		1286	defined wantarray
		1287	? bless \$cb, "AnyEvent::Util::postdetect"
		1288	: ()
		1289	}
		1290
		1291	sub AnyEvent::Util::postdetect::DESTROY {
		1292	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1293	}
		1294
		1295	our $POSTPONE_W;
		1296	our @POSTPONE;
		1297
		1298	sub _postpone_exec {
		1299	undef $POSTPONE_W;
		1300
		1301	&{ shift @POSTPONE }
		1302	while @POSTPONE;
		1303	}
		1304
		1305	sub postpone(&) {
		1306	push @POSTPONE, shift;
		1307
		1308	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1309
		1310	()
		1311	}
		1312
		1313	sub log($$;@) {
		1314	# only load the big bloated module when we actually are about to log something
		1315	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1316	local ($!, $@);
		1317	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1318	# AnyEvent::Log overwrites this function
		1319	goto &log;
		1320	}
		1321
		1322	0 # not logged
		1323	}
		1324
		1325	sub _logger($;$) {
		1326	my ($level, $renabled) = @_;
		1327
		1328	$$renabled = $level <= $VERBOSE;
		1329
		1330	my $logger = [(caller)[0], $level, $renabled];
		1331
		1332	$AnyEvent::Log::LOGGER{$logger+0} = $logger;
		1333
		1334	# return unless defined wantarray;
		1335	#
		1336	# require AnyEvent::Util;
		1337	# my $guard = AnyEvent::Util::guard (sub {
		1338	# # "clean up"
		1339	# delete $LOGGER{$logger+0};
		1340	# });
		1341	#
		1342	# sub {
		1343	# return 0 unless $$renabled;
		1344	#
		1345	# $guard if 0; # keep guard alive, but don't cause runtime overhead
		1346	# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1347	# package AnyEvent::Log;
		1348	# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1349	# }
		1350	}
		1351
		1352	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1353	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1354	}
		1355
999	my @models = (	1356	our @models = (
1000	[EV:: => AnyEvent::Impl::EV::],	1357	[EV:: => AnyEvent::Impl::EV::],
1001	[Event:: => AnyEvent::Impl::Event::],
1002	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1358	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1003	# everything below here will not be autoprobed	1359	# everything below here will not (normally) be autoprobed
1004	# as the pureperl backend should work everywhere	1360	# as the pure perl backend should work everywhere
1005	# and is usually faster	1361	# and is usually faster
		1362	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
		1363	[Event:: => AnyEvent::Impl::Event::], # slow, stable
		1364	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1365	# everything below here should not be autoloaded
		1366	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1006	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1367	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1007	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1008	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1009	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1368	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1010	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1369	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1011	[Wx:: => AnyEvent::Impl::POE::],	1370	[Wx:: => AnyEvent::Impl::POE::],
1012	[Prima:: => AnyEvent::Impl::POE::],	1371	[Prima:: => AnyEvent::Impl::POE::],
1013	# IO::Async is just too broken - we would need workaorunds for its	1372	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1014	# byzantine signal and broken child handling, among others.	1373	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1015	# IO::Async is rather hard to detect, as it doesn't have any	1374	[FLTK:: => AnyEvent::Impl::FLTK::],
1016	# obvious default class.
1017	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1018	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1019	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1020	);	1375	);
1021		1376
1022	our %method = map +($_ => 1),	1377	our @isa_hook;
		1378
		1379	sub _isa_set {
		1380	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1381
		1382	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1383	for 1 .. $#pkg;
		1384
		1385	grep $_ && $_->[1], @isa_hook
		1386	and AE::_reset ();
		1387	}
		1388
		1389	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1390	sub _isa_hook($$;$) {
		1391	my ($i, $pkg, $reset_ae) = @_;
		1392
		1393	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1394
		1395	_isa_set;
		1396	}
		1397
		1398	# all autoloaded methods reserve the complete glob, not just the method slot.
		1399	# due to bugs in perls method cache implementation.
1023	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1400	our @methods = qw(io timer time now now_update signal child idle condvar);
1024		1401
1025	our @post_detect;
1026
1027	sub post_detect(&) {	1402	sub detect() {
1028	my ($cb) = @_;	1403	return $MODEL if $MODEL; # some programs keep references to detect
1029		1404
1030	if ($MODEL) {	1405	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1031	$cb->();	1406	# the author knows about the problems and what it does to AnyEvent as a whole
		1407	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1408	# anyway.
		1409	AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
		1410	. "design, abuses internals and breaks AnyEvent - will not continue."
		1411	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1032		1412
1033	1	1413	local $!; # for good measure
		1414	local $SIG{__DIE__}; # we use eval
		1415
		1416	# free some memory
		1417	*detect = sub () { $MODEL };
		1418	# undef &func doesn't correctly update the method cache. grmbl.
		1419	# so we delete the whole glob. grmbl.
		1420	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1421	# a glob with an active sub. hrm. i hope it works, but perl is
		1422	# usually buggy in this department. sigh.
		1423	delete @{"AnyEvent::"}{@methods};
		1424	undef @methods;
		1425
		1426	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1427	my $model = $1;
		1428	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1429	if (eval "require $model") {
		1430	AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1431	$MODEL = $model;
1034	} else {	1432	} else {
1035	push @post_detect, $cb;	1433	AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1036		1434	}
1037	defined wantarray
1038	? bless \$cb, "AnyEvent::Util::postdetect"
1039	: ()
1040	}	1435	}
1041	}
1042		1436
1043	sub AnyEvent::Util::postdetect::DESTROY {	1437	# check for already loaded models
1044	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1045	}
1046
1047	sub detect() {
1048	unless ($MODEL) {	1438	unless ($MODEL) {
1049	no strict 'refs';	1439	for (@REGISTRY, @models) {
1050	local $SIG{__DIE__};	1440	my ($package, $model) = @$_;
1051		1441	if (${"$package\::VERSION"} > 0) {
1052	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1053	my $model = "AnyEvent::Impl::$1";
1054	if (eval "require $model") {	1442	if (eval "require $model") {
		1443	AnyEvent::log 7 => "Autodetected model '$model', using it.";
1055	$MODEL = $model;	1444	$MODEL = $model;
1056	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1445	last;
1057	} else {	1446	} else {
1058	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1447	AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
		1448	}
1059	}	1449	}
1060	}	1450	}
1061		1451
1062	# check for already loaded models
1063	unless ($MODEL) {	1452	unless ($MODEL) {
		1453	# try to autoload a model
1064	for (@REGISTRY, @models) {	1454	for (@REGISTRY, @models) {
1065	my ($package, $model) = @$_;	1455	my ($package, $model) = @$_;
		1456	if (
		1457	eval "require $package"
1066	if (${"$package\::VERSION"} > 0) {	1458	and ${"$package\::VERSION"} > 0
1067	if (eval "require $model") {	1459	and eval "require $model"
		1460	) {
		1461	AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1068	$MODEL = $model;	1462	$MODEL = $model;
1069	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
1070	last;	1463	last;
1071	}
1072	}	1464	}
1073	}	1465	}
1074		1466
1075	unless ($MODEL) {
1076	# try to load a model
1077
1078	for (@REGISTRY, @models) {
1079	my ($package, $model) = @$_;
1080	if (eval "require $package"
1081	and ${"$package\::VERSION"} > 0
1082	and eval "require $model") {
1083	$MODEL = $model;
1084	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1085	last;
1086	}
1087	}
1088
1089	$MODEL	1467	$MODEL
1090	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1468	or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1091	}
1092	}	1469	}
1093
1094	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1095
1096	unshift @ISA, $MODEL;
1097
1098	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1099
1100	(shift @post_detect)->() while @post_detect;
1101	}	1470	}
1102		1471
		1472	# free memory only needed for probing
		1473	undef @models;
		1474	undef @REGISTRY;
		1475
		1476	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1477
		1478	# now nuke some methods that are overridden by the backend.
		1479	# SUPER usage is not allowed in these.
		1480	for (qw(time signal child idle)) {
		1481	undef &{"AnyEvent::Base::$_"}
		1482	if defined &{"$MODEL\::$_"};
		1483	}
		1484
		1485	_isa_set;
		1486
		1487	# we're officially open!
		1488
		1489	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1490	require AnyEvent::Strict;
		1491	}
		1492
		1493	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1494	require AnyEvent::Debug;
		1495	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1496	}
		1497
		1498	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1499	require AnyEvent::Socket;
		1500	require AnyEvent::Debug;
		1501
		1502	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1503	$shell =~ s/\$\$/$$/g;
		1504
		1505	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1506	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1507	}
		1508
		1509	# now the anyevent environment is set up as the user told us to, so
		1510	# call the actual user code - post detects
		1511
		1512	(shift @post_detect)->() while @post_detect;
		1513	undef @post_detect;
		1514
		1515	*post_detect = sub(&) {
		1516	shift->();
		1517
		1518	undef
		1519	};
		1520
1103	$MODEL	1521	$MODEL
1104	}	1522	}
1105		1523
1106	sub AUTOLOAD {	1524	for my $name (@methods) {
1107	(my $func = $AUTOLOAD) =~ s/.*://;	1525	*$name = sub {
1108		1526	detect;
1109	$method{$func}	1527	# we use goto because
1110	or croak "$func: not a valid method for AnyEvent objects";	1528	# a) it makes the thunk more transparent
1111		1529	# b) it allows us to delete the thunk later
1112	detect unless $MODEL;	1530	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1113		1531	};
1114	my $class = shift;
1115	$class->$func (@_);
1116	}	1532	}
1117		1533
1118	# utility function to dup a filehandle. this is used by many backends	1534	# utility function to dup a filehandle. this is used by many backends
1119	# to support binding more than one watcher per filehandle (they usually	1535	# to support binding more than one watcher per filehandle (they usually
1120	# allow only one watcher per fd, so we dup it to get a different one).	1536	# allow only one watcher per fd, so we dup it to get a different one).
1121	sub _dupfh($$;$$) {	1537	sub _dupfh($$;$$) {
1122	my ($poll, $fh, $r, $w) = @_;	1538	my ($poll, $fh, $r, $w) = @_;
1123		1539
1124	# cygwin requires the fh mode to be matching, unix doesn't	1540	# cygwin requires the fh mode to be matching, unix doesn't
1125	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1541	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1126		1542
1127	open my $fh2, "$mode&", $fh	1543	open my $fh2, $mode, $fh
1128	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1544	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1129		1545
1130	# we assume CLOEXEC is already set by perl in all important cases	1546	# we assume CLOEXEC is already set by perl in all important cases
1131		1547
1132	($fh2, $rw)	1548	($fh2, $rw)
1133	}	1549	}
1134		1550
		1551	=head1 SIMPLIFIED AE API
		1552
		1553	Starting with version 5.0, AnyEvent officially supports a second, much
		1554	simpler, API that is designed to reduce the calling, typing and memory
		1555	overhead by using function call syntax and a fixed number of parameters.
		1556
		1557	See the L<AE> manpage for details.
		1558
		1559	=cut
		1560
		1561	package AE;
		1562
		1563	our $VERSION = $AnyEvent::VERSION;
		1564
		1565	sub _reset() {
		1566	eval q{
		1567	# fall back to the main API by default - backends and AnyEvent::Base
		1568	# implementations can overwrite these.
		1569
		1570	sub io($$$) {
		1571	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1572	}
		1573
		1574	sub timer($$$) {
		1575	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1576	}
		1577
		1578	sub signal($$) {
		1579	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1580	}
		1581
		1582	sub child($$) {
		1583	AnyEvent->child (pid => $_[0], cb => $_[1])
		1584	}
		1585
		1586	sub idle($) {
		1587	AnyEvent->idle (cb => $_[0]);
		1588	}
		1589
		1590	sub cv(;&) {
		1591	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1592	}
		1593
		1594	sub now() {
		1595	AnyEvent->now
		1596	}
		1597
		1598	sub now_update() {
		1599	AnyEvent->now_update
		1600	}
		1601
		1602	sub time() {
		1603	AnyEvent->time
		1604	}
		1605
		1606	*postpone = \&AnyEvent::postpone;
		1607	*log = \&AnyEvent::log;
		1608	};
		1609	die if $@;
		1610	}
		1611
		1612	BEGIN { _reset }
		1613
1135	package AnyEvent::Base;	1614	package AnyEvent::Base;
1136		1615
1137	# default implementations for many methods	1616	# default implementations for many methods
1138		1617
1139	BEGIN {	1618	sub time {
		1619	eval q{ # poor man's autoloading {}
		1620	# probe for availability of Time::HiRes
1140	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1621	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1622	*time = sub { Time::HiRes::time () };
1141	*_time = \&Time::HiRes::time;	1623	*AE::time = \& Time::HiRes::time ;
		1624	*now = \&time;
		1625	AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1142	# if (eval "use POSIX (); (POSIX::times())...	1626	# if (eval "use POSIX (); (POSIX::times())...
1143	} else {	1627	} else {
1144	*_time = sub { time }; # epic fail	1628	*time = sub { CORE::time };
		1629	*AE::time = sub (){ CORE::time };
		1630	*now = \&time;
		1631	AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
		1632	}
		1633	};
		1634	die if $@;
		1635
		1636	&time
		1637	}
		1638
		1639	*now = \&time;
		1640	sub now_update { }
		1641
		1642	sub _poll {
		1643	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1644	}
		1645
		1646	# default implementation for ->condvar
		1647	# in fact, the default should not be overwritten
		1648
		1649	sub condvar {
		1650	eval q{ # poor man's autoloading {}
		1651	*condvar = sub {
		1652	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1653	};
		1654
		1655	*AE::cv = sub (;&) {
		1656	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1657	};
		1658	};
		1659	die if $@;
		1660
		1661	&condvar
		1662	}
		1663
		1664	# default implementation for ->signal
		1665
		1666	our $HAVE_ASYNC_INTERRUPT;
		1667
		1668	sub _have_async_interrupt() {
		1669	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1670	&& eval "use Async::Interrupt 1.02 (); 1")
		1671	unless defined $HAVE_ASYNC_INTERRUPT;
		1672
		1673	$HAVE_ASYNC_INTERRUPT
		1674	}
		1675
		1676	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1677	our (%SIG_ASY, %SIG_ASY_W);
		1678	our ($SIG_COUNT, $SIG_TW);
		1679
		1680	# install a dummy wakeup watcher to reduce signal catching latency
		1681	# used by Impls
		1682	sub _sig_add() {
		1683	unless ($SIG_COUNT++) {
		1684	# try to align timer on a full-second boundary, if possible
		1685	my $NOW = AE::now;
		1686
		1687	$SIG_TW = AE::timer
		1688	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1689	$MAX_SIGNAL_LATENCY,
		1690	sub { } # just for the PERL_ASYNC_CHECK
		1691	;
1145	}	1692	}
1146	}	1693	}
1147		1694
1148	sub time { _time }	1695	sub _sig_del {
1149	sub now { _time }	1696	undef $SIG_TW
1150	sub now_update { }	1697	unless --$SIG_COUNT;
1151
1152	# default implementation for ->condvar
1153
1154	sub condvar {
1155	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1156	}	1698	}
1157		1699
1158	# default implementation for ->signal	1700	our $_sig_name_init; $_sig_name_init = sub {
		1701	eval q{ # poor man's autoloading {}
		1702	undef $_sig_name_init;
1159		1703
1160	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1704	if (_have_async_interrupt) {
		1705	*sig2num = \&Async::Interrupt::sig2num;
		1706	*sig2name = \&Async::Interrupt::sig2name;
		1707	} else {
		1708	require Config;
1161		1709
1162	sub _signal_exec {	1710	my %signame2num;
1163	sysread $SIGPIPE_R, my $dummy, 4;	1711	@signame2num{ split ' ', $Config::Config{sig_name} }
		1712	= split ' ', $Config::Config{sig_num};
1164		1713
1165	while (%SIG_EV) {	1714	my @signum2name;
1166	for (keys %SIG_EV) {	1715	@signum2name[values %signame2num] = keys %signame2num;
1167	delete $SIG_EV{$_};	1716
1168	$_->() for values %{ $SIG_CB{$_} || {} };	1717	*sig2num = sub($) {
		1718	$_[0] > 0 ? shift : $signame2num{+shift}
		1719	};
		1720	*sig2name = sub ($) {
		1721	$_[0] > 0 ? $signum2name[+shift] : shift
		1722	};
1169	}	1723	}
1170	}	1724	};
1171	}	1725	die if $@;
		1726	};
		1727
		1728	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1729	sub sig2name($) { &$_sig_name_init; &sig2name }
1172		1730
1173	sub signal {	1731	sub signal {
1174	my (undef, %arg) = @_;	1732	eval q{ # poor man's autoloading {}
		1733	# probe for availability of Async::Interrupt
		1734	if (_have_async_interrupt) {
		1735	AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1175		1736
1176	unless ($SIGPIPE_R) {	1737	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1177	require Fcntl;	1738	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1178		1739
1179	if (AnyEvent::WIN32) {
1180	require AnyEvent::Util;
1181
1182	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1183	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1184	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1185	} else {	1740	} else {
		1741	AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
		1742
		1743	if (AnyEvent::WIN32) {
		1744	require AnyEvent::Util;
		1745
		1746	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1747	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1748	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1749	} else {
1186	pipe $SIGPIPE_R, $SIGPIPE_W;	1750	pipe $SIGPIPE_R, $SIGPIPE_W;
1187	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1751	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1188	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1752	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1189		1753
1190	# not strictly required, as $^F is normally 2, but let's make sure...	1754	# not strictly required, as $^F is normally 2, but let's make sure...
1191	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1755	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1192	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1756	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1757	}
		1758
		1759	$SIGPIPE_R
		1760	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1761
		1762	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1193	}	1763	}
1194		1764
1195	$SIGPIPE_R	1765	*signal = $HAVE_ASYNC_INTERRUPT
1196	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1766	? sub {
		1767	my (undef, %arg) = @_;
1197		1768
1198	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1769	# async::interrupt
1199	}
1200
1201	my $signal = uc $arg{signal}	1770	my $signal = sig2num $arg{signal};
1202	or Carp::croak "required option 'signal' is missing";
1203
1204	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1771	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1772
		1773	$SIG_ASY{$signal} ||= new Async::Interrupt
		1774	cb => sub { undef $SIG_EV{$signal} },
		1775	signal => $signal,
		1776	pipe => [$SIGPIPE_R->filenos],
		1777	pipe_autodrain => 0,
		1778	;
		1779
		1780	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1781	}
		1782	: sub {
		1783	my (undef, %arg) = @_;
		1784
		1785	# pure perl
		1786	my $signal = sig2name $arg{signal};
		1787	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1788
1205	$SIG{$signal} ||= sub {	1789	$SIG{$signal} ||= sub {
1206	local $!;	1790	local $!;
1207	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1791	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1208	undef $SIG_EV{$signal};	1792	undef $SIG_EV{$signal};
		1793	};
		1794
		1795	# can't do signal processing without introducing races in pure perl,
		1796	# so limit the signal latency.
		1797	_sig_add;
		1798
		1799	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1800	}
		1801	;
		1802
		1803	*AnyEvent::Base::signal::DESTROY = sub {
		1804	my ($signal, $cb) = @{$_[0]};
		1805
		1806	_sig_del;
		1807
		1808	delete $SIG_CB{$signal}{$cb};
		1809
		1810	$HAVE_ASYNC_INTERRUPT
		1811	? delete $SIG_ASY{$signal}
		1812	: # delete doesn't work with older perls - they then
		1813	# print weird messages, or just unconditionally exit
		1814	# instead of getting the default action.
		1815	undef $SIG{$signal}
		1816	unless keys %{ $SIG_CB{$signal} };
		1817	};
		1818
		1819	*_signal_exec = sub {
		1820	$HAVE_ASYNC_INTERRUPT
		1821	? $SIGPIPE_R->drain
		1822	: sysread $SIGPIPE_R, (my $dummy), 9;
		1823
		1824	while (%SIG_EV) {
		1825	for (keys %SIG_EV) {
		1826	delete $SIG_EV{$_};
		1827	&$_ for values %{ $SIG_CB{$_} || {} };
		1828	}
		1829	}
		1830	};
1209	};	1831	};
		1832	die if $@;
1210		1833
1211	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1834	&signal
1212	}
1213
1214	sub AnyEvent::Base::signal::DESTROY {
1215	my ($signal, $cb) = @{$_[0]};
1216
1217	delete $SIG_CB{$signal}{$cb};
1218
1219	# delete doesn't work with older perls - they then
1220	# print weird messages, or just unconditionally exit
1221	# instead of getting the default action.
1222	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1223	}	1835	}
1224		1836
1225	# default implementation for ->child	1837	# default implementation for ->child
1226		1838
1227	our %PID_CB;	1839	our %PID_CB;
1228	our $CHLD_W;	1840	our $CHLD_W;
1229	our $CHLD_DELAY_W;	1841	our $CHLD_DELAY_W;
1230	our $WNOHANG;
1231		1842
1232	sub _sigchld {	1843	# used by many Impl's
1233	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1844	sub _emit_childstatus($$) {
		1845	my (undef, $rpid, $rstatus) = @_;
		1846
		1847	$_->($rpid, $rstatus)
1234	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1848	for values %{ $PID_CB{$rpid} || {} },
1235	(values %{ $PID_CB{0} || {} });	1849	values %{ $PID_CB{0} || {} };
1236	}
1237	}	1850	}
1238		1851
1239	sub child {	1852	sub child {
		1853	eval q{ # poor man's autoloading {}
		1854	*_sigchld = sub {
		1855	my $pid;
		1856
		1857	AnyEvent->_emit_childstatus ($pid, $?)
		1858	while ($pid = waitpid -1, WNOHANG) > 0;
		1859	};
		1860
		1861	*child = sub {
1240	my (undef, %arg) = @_;	1862	my (undef, %arg) = @_;
1241		1863
1242	defined (my $pid = $arg{pid} + 0)	1864	my $pid = $arg{pid};
1243	or Carp::croak "required option 'pid' is missing";	1865	my $cb = $arg{cb};
1244		1866
1245	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1867	$PID_CB{$pid}{$cb+0} = $cb;
1246		1868
1247	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1248
1249	unless ($CHLD_W) {	1869	unless ($CHLD_W) {
1250	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1870	$CHLD_W = AE::signal CHLD => \&_sigchld;
1251	# child could be a zombie already, so make at least one round	1871	# child could be a zombie already, so make at least one round
1252	&_sigchld;	1872	&_sigchld;
1253	}	1873	}
1254		1874
1255	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1875	bless [$pid, $cb+0], "AnyEvent::Base::child"
1256	}	1876	};
1257		1877
1258	sub AnyEvent::Base::child::DESTROY {	1878	*AnyEvent::Base::child::DESTROY = sub {
1259	my ($pid, $cb) = @{$_[0]};	1879	my ($pid, $icb) = @{$_[0]};
1260		1880
1261	delete $PID_CB{$pid}{$cb};	1881	delete $PID_CB{$pid}{$icb};
1262	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1882	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1263		1883
1264	undef $CHLD_W unless keys %PID_CB;	1884	undef $CHLD_W unless keys %PID_CB;
		1885	};
		1886	};
		1887	die if $@;
		1888
		1889	&child
1265	}	1890	}
1266		1891
1267	# idle emulation is done by simply using a timer, regardless	1892	# idle emulation is done by simply using a timer, regardless
1268	# of whether the process is idle or not, and not letting	1893	# of whether the process is idle or not, and not letting
1269	# the callback use more than 50% of the time.	1894	# the callback use more than 50% of the time.
1270	sub idle {	1895	sub idle {
		1896	eval q{ # poor man's autoloading {}
		1897	*idle = sub {
1271	my (undef, %arg) = @_;	1898	my (undef, %arg) = @_;
1272		1899
1273	my ($cb, $w, $rcb) = $arg{cb};	1900	my ($cb, $w, $rcb) = $arg{cb};
1274		1901
1275	$rcb = sub {	1902	$rcb = sub {
1276	if ($cb) {	1903	if ($cb) {
1277	$w = _time;	1904	$w = AE::time;
1278	&$cb;	1905	&$cb;
1279	$w = _time - $w;	1906	$w = AE::time - $w;
1280		1907
1281	# never use more then 50% of the time for the idle watcher,	1908	# never use more then 50% of the time for the idle watcher,
1282	# within some limits	1909	# within some limits
1283	$w = 0.0001 if $w < 0.0001;	1910	$w = 0.0001 if $w < 0.0001;
1284	$w = 5 if $w > 5;	1911	$w = 5 if $w > 5;
1285		1912
1286	$w = AnyEvent->timer (after => $w, cb => $rcb);	1913	$w = AE::timer $w, 0, $rcb;
1287	} else {	1914	} else {
1288	# clean up...	1915	# clean up...
1289	undef $w;	1916	undef $w;
1290	undef $rcb;	1917	undef $rcb;
		1918	}
		1919	};
		1920
		1921	$w = AE::timer 0.05, 0, $rcb;
		1922
		1923	bless \\$cb, "AnyEvent::Base::idle"
1291	}	1924	};
		1925
		1926	*AnyEvent::Base::idle::DESTROY = sub {
		1927	undef $${$_[0]};
		1928	};
1292	};	1929	};
		1930	die if $@;
1293		1931
1294	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1932	&idle
1295
1296	bless \\$cb, "AnyEvent::Base::idle"
1297	}
1298
1299	sub AnyEvent::Base::idle::DESTROY {
1300	undef $${$_[0]};
1301	}	1933	}
1302		1934
1303	package AnyEvent::CondVar;	1935	package AnyEvent::CondVar;
1304		1936
1305	our @ISA = AnyEvent::CondVar::Base::;	1937	our @ISA = AnyEvent::CondVar::Base::;
1306		1938
		1939	# only to be used for subclassing
		1940	sub new {
		1941	my $class = shift;
		1942	bless AnyEvent->condvar (@_), $class
		1943	}
		1944
1307	package AnyEvent::CondVar::Base;	1945	package AnyEvent::CondVar::Base;
1308		1946
1309	use overload	1947	#use overload
1310	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1948	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1311	fallback => 1;	1949	# fallback => 1;
		1950
		1951	# save 300+ kilobytes by dirtily hardcoding overloading
		1952	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1953	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1954	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1955	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1956
		1957	our $WAITING;
1312		1958
1313	sub _send {	1959	sub _send {
1314	# nop	1960	# nop
		1961	}
		1962
		1963	sub _wait {
		1964	AnyEvent->_poll until $_[0]{_ae_sent};
1315	}	1965	}
1316		1966
1317	sub send {	1967	sub send {
1318	my $cv = shift;	1968	my $cv = shift;
1319	$cv->{_ae_sent} = [@_];	1969	$cv->{_ae_sent} = [@_];
…		…
1328		1978
1329	sub ready {	1979	sub ready {
1330	$_[0]{_ae_sent}	1980	$_[0]{_ae_sent}
1331	}	1981	}
1332		1982
1333	sub _wait {
1334	AnyEvent->one_event while !$_[0]{_ae_sent};
1335	}
1336
1337	sub recv {	1983	sub recv {
		1984	unless ($_[0]{_ae_sent}) {
		1985	$WAITING
		1986	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1987
		1988	local $WAITING = 1;
1338	$_[0]->_wait;	1989	$_[0]->_wait;
		1990	}
1339		1991
1340	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1992	$_[0]{_ae_croak}
1341	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1993	and Carp::croak $_[0]{_ae_croak};
		1994
		1995	wantarray
		1996	? @{ $_[0]{_ae_sent} }
		1997	: $_[0]{_ae_sent}[0]
1342	}	1998	}
1343		1999
1344	sub cb {	2000	sub cb {
1345	$_[0]{_ae_cb} = $_[1] if @_ > 1;	2001	my $cv = shift;
		2002
		2003	@_
		2004	and $cv->{_ae_cb} = shift
		2005	and $cv->{_ae_sent}
		2006	and (delete $cv->{_ae_cb})->($cv);
		2007
1346	$_[0]{_ae_cb}	2008	$cv->{_ae_cb}
1347	}	2009	}
1348		2010
1349	sub begin {	2011	sub begin {
1350	++$_[0]{_ae_counter};	2012	++$_[0]{_ae_counter};
1351	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	2013	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1356	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2018	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1357	}	2019	}
1358		2020
1359	# undocumented/compatibility with pre-3.4	2021	# undocumented/compatibility with pre-3.4
1360	*broadcast = \&send;	2022	*broadcast = \&send;
1361	*wait = \&_wait;	2023	*wait = \&recv;
1362		2024
1363	=head1 ERROR AND EXCEPTION HANDLING	2025	=head1 ERROR AND EXCEPTION HANDLING
1364		2026
1365	In general, AnyEvent does not do any error handling - it relies on the	2027	In general, AnyEvent does not do any error handling - it relies on the
1366	caller to do that if required. The L<AnyEvent::Strict> module (see also	2028	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1378	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2040	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1379	so on.	2041	so on.
1380		2042
1381	=head1 ENVIRONMENT VARIABLES	2043	=head1 ENVIRONMENT VARIABLES
1382		2044
1383	The following environment variables are used by this module or its	2045	AnyEvent supports a number of environment variables that tune the
1384	submodules.	2046	runtime behaviour. They are usually evaluated when AnyEvent is
		2047	loaded, initialised, or a submodule that uses them is loaded. Many of
		2048	them also cause AnyEvent to load additional modules - for example,
		2049	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2050	loaded.
1385		2051
1386	Note that AnyEvent will remove I<all> environment variables starting with	2052	All the environment variables documented here start with
1387	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2053	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1388	enabled.	2054	namespace. Other modules are encouraged (but by no means required) to use
		2055	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2056	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2057	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2058	variables starting with C<AE_>, see below).
		2059
		2060	All variables can also be set via the C<AE_> prefix, that is, instead
		2061	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2062	case there is a clash btween anyevent and another program that uses
		2063	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2064	variable to the empty string, as those variables take precedence.
		2065
		2066	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2067	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2068	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2069	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2070	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2071	is set).
		2072
		2073	The exact algorithm is currently:
		2074
		2075	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2076	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2077	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2078
		2079	This ensures that child processes will not see the C<AE_> variables.
		2080
		2081	The following environment variables are currently known to AnyEvent:
1389		2082
1390	=over 4	2083	=over 4
1391		2084
1392	=item C<PERL_ANYEVENT_VERBOSE>	2085	=item C<PERL_ANYEVENT_VERBOSE>
1393		2086
1394	By default, AnyEvent will be completely silent except in fatal	2087	By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1395	conditions. You can set this environment variable to make AnyEvent more	2088	higher (see L<AnyEvent::Log>). You can set this environment variable to a
1396	talkative.	2089	numerical loglevel to make AnyEvent more (or less) talkative.
1397		2090
		2091	If you want to do more than just set the global logging level
		2092	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2093	complex specifications.
		2094
		2095	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2096	everything else at defaults.
		2097
1398	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2098	When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1399	conditions, such as not being able to load the event model specified by	2099	conditions, such as not being able to load the event model specified by
1400	C<PERL_ANYEVENT_MODEL>.	2100	C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
		2101	is the minimum recommended level for use during development.
1401		2102
1402	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2103	When set to C<7> or higher (info), AnyEvent reports which event model it
1403	model it chooses.	2104	chooses.
		2105
		2106	When set to C<8> or higher (debug), then AnyEvent will report extra
		2107	information on which optional modules it loads and how it implements
		2108	certain features.
		2109
		2110	=item C<PERL_ANYEVENT_LOG>
		2111
		2112	Accepts rather complex logging specifications. For example, you could log
		2113	all C<debug> messages of some module to stderr, warnings and above to
		2114	stderr, and errors and above to syslog, with:
		2115
		2116	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2117
		2118	For the rather extensive details, see L<AnyEvent::Log>.
		2119
		2120	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2121	so will take effect even before AnyEvent has initialised itself.
		2122
		2123	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2124	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2125	using the latter saves a few hundred kB of memory unless a module
		2126	explicitly needs the extra features of AnyEvent::Log.
1404		2127
1405	=item C<PERL_ANYEVENT_STRICT>	2128	=item C<PERL_ANYEVENT_STRICT>
1406		2129
1407	AnyEvent does not do much argument checking by default, as thorough	2130	AnyEvent does not do much argument checking by default, as thorough
1408	argument checking is very costly. Setting this variable to a true value	2131	argument checking is very costly. Setting this variable to a true value
…		…
1410	check the arguments passed to most method calls. If it finds any problems,	2133	check the arguments passed to most method calls. If it finds any problems,
1411	it will croak.	2134	it will croak.
1412		2135
1413	In other words, enables "strict" mode.	2136	In other words, enables "strict" mode.
1414		2137
1415	Unlike C<use strict>, it is definitely recommended to keep it off in	2138	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1416	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2139	>>, it is definitely recommended to keep it off in production. Keeping
1417	developing programs can be very useful, however.	2140	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2141	can be very useful, however.
		2142
		2143	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2144
		2145	If this env variable is nonempty, then its contents will be interpreted by
		2146	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2147	replacing every occurance of C<$$> by the process pid). The shell object
		2148	is saved in C<$AnyEvent::Debug::SHELL>.
		2149
		2150	This happens when the first watcher is created.
		2151
		2152	For example, to bind a debug shell on a unix domain socket in
		2153	F<< /tmp/debug<pid>.sock >>, you could use this:
		2154
		2155	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2156	# connect with e.g.: socat readline /tmp/debug123.sock
		2157
		2158	Or to bind to tcp port 4545 on localhost:
		2159
		2160	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2161	# connect with e.g.: telnet localhost 4545
		2162
		2163	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2164	multiuser systems.
		2165
		2166	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2167
		2168	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2169	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1418		2170
1419	=item C<PERL_ANYEVENT_MODEL>	2171	=item C<PERL_ANYEVENT_MODEL>
1420		2172
1421	This can be used to specify the event model to be used by AnyEvent, before	2173	This can be used to specify the event model to be used by AnyEvent, before
1422	auto detection and -probing kicks in. It must be a string consisting	2174	auto detection and -probing kicks in.
1423	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2175
		2176	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2177	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1424	and the resulting module name is loaded and if the load was successful,	2178	resulting module name is loaded and - if the load was successful - used as
1425	used as event model. If it fails to load AnyEvent will proceed with	2179	event model backend. If it fails to load then AnyEvent will proceed with
1426	auto detection and -probing.	2180	auto detection and -probing.
1427		2181
1428	This functionality might change in future versions.	2182	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2183	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2184	the end of a string designates a module name and quotes it appropriately).
1429		2185
1430	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2186	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1431	could start your program like this:	2187	could start your program like this:
1432		2188
1433	PERL_ANYEVENT_MODEL=Perl perl ...	2189	PERL_ANYEVENT_MODEL=Perl perl ...
		2190
		2191	=item C<PERL_ANYEVENT_IO_MODEL>
		2192
		2193	The current file I/O model - see L<AnyEvent::IO> for more info.
		2194
		2195	At the moment, only C<Perl> (small, pure-perl, synchronous) and
		2196	C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
		2197	L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1434		2198
1435	=item C<PERL_ANYEVENT_PROTOCOLS>	2199	=item C<PERL_ANYEVENT_PROTOCOLS>
1436		2200
1437	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences	2201	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1438	for IPv4 or IPv6. The default is unspecified (and might change, or be the result	2202	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
…		…
1451	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2215	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1452	- only support IPv4, never try to resolve or contact IPv6	2216	- only support IPv4, never try to resolve or contact IPv6
1453	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2217	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1454	IPv6, but prefer IPv6 over IPv4.	2218	IPv6, but prefer IPv6 over IPv4.
1455		2219
		2220	=item C<PERL_ANYEVENT_HOSTS>
		2221
		2222	This variable, if specified, overrides the F</etc/hosts> file used by
		2223	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2224	from that file instead.
		2225
1456	=item C<PERL_ANYEVENT_EDNS0>	2226	=item C<PERL_ANYEVENT_EDNS0>
1457		2227
1458	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2228	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1459	for DNS. This extension is generally useful to reduce DNS traffic, but	2229	DNS. This extension is generally useful to reduce DNS traffic, especially
1460	some (broken) firewalls drop such DNS packets, which is why it is off by	2230	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1461	default.	2231	packets, which is why it is off by default.
1462		2232
1463	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2233	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1464	EDNS0 in its DNS requests.	2234	EDNS0 in its DNS requests.
1465		2235
1466	=item C<PERL_ANYEVENT_MAX_FORKS>	2236	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1472		2242
1473	The default value for the C<max_outstanding> parameter for the default DNS	2243	The default value for the C<max_outstanding> parameter for the default DNS
1474	resolver - this is the maximum number of parallel DNS requests that are	2244	resolver - this is the maximum number of parallel DNS requests that are
1475	sent to the DNS server.	2245	sent to the DNS server.
1476		2246
		2247	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2248
		2249	Perl has inherently racy signal handling (you can basically choose between
		2250	losing signals and memory corruption) - pure perl event loops (including
		2251	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2252	have to poll regularly to avoid losing signals.
		2253
		2254	Some event loops are racy, but don't poll regularly, and some event loops
		2255	are written in C but are still racy. For those event loops, AnyEvent
		2256	installs a timer that regularly wakes up the event loop.
		2257
		2258	By default, the interval for this timer is C<10> seconds, but you can
		2259	override this delay with this environment variable (or by setting
		2260	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2261	watchers).
		2262
		2263	Lower values increase CPU (and energy) usage, higher values can introduce
		2264	long delays when reaping children or waiting for signals.
		2265
		2266	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2267	polling (with most event loops).
		2268
1477	=item C<PERL_ANYEVENT_RESOLV_CONF>	2269	=item C<PERL_ANYEVENT_RESOLV_CONF>
1478		2270
1479	The file to use instead of F</etc/resolv.conf> (or OS-specific	2271	The absolute path to a F<resolv.conf>-style file to use instead of
1480	configuration) in the default resolver. When set to the empty string, no	2272	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1481	default config will be used.	2273	resolver, or the empty string to select the default configuration.
1482		2274
1483	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2275	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1484		2276
1485	When neither C<ca_file> nor C<ca_path> was specified during	2277	When neither C<ca_file> nor C<ca_path> was specified during
1486	L<AnyEvent::TLS> context creation, and either of these environment	2278	L<AnyEvent::TLS> context creation, and either of these environment
1487	variables exist, they will be used to specify CA certificate locations	2279	variables are nonempty, they will be used to specify CA certificate
1488	instead of a system-dependent default.	2280	locations instead of a system-dependent default.
		2281
		2282	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2283
		2284	When these are set to C<1>, then the respective modules are not
		2285	loaded. Mostly good for testing AnyEvent itself.
1489		2286
1490	=back	2287	=back
1491		2288
1492	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2289	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1493		2290
…		…
1551	warn "read: $input\n"; # output what has been read	2348	warn "read: $input\n"; # output what has been read
1552	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2349	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1553	},	2350	},
1554	);	2351	);
1555		2352
1556	my $time_watcher; # can only be used once
1557
1558	sub new_timer {
1559	$timer = AnyEvent->timer (after => 1, cb => sub {	2353	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1560	warn "timeout\n"; # print 'timeout' about every second	2354	warn "timeout\n"; # print 'timeout' at most every second
1561	&new_timer; # and restart the time
1562	});	2355	});
1563	}
1564
1565	new_timer; # create first timer
1566		2356
1567	$cv->recv; # wait until user enters /^q/i	2357	$cv->recv; # wait until user enters /^q/i
1568		2358
1569	=head1 REAL-WORLD EXAMPLE	2359	=head1 REAL-WORLD EXAMPLE
1570		2360
…		…
1643		2433
1644	The actual code goes further and collects all errors (C<die>s, exceptions)	2434	The actual code goes further and collects all errors (C<die>s, exceptions)
1645	that occurred during request processing. The C<result> method detects	2435	that occurred during request processing. The C<result> method detects
1646	whether an exception as thrown (it is stored inside the $txn object)	2436	whether an exception as thrown (it is stored inside the $txn object)
1647	and just throws the exception, which means connection errors and other	2437	and just throws the exception, which means connection errors and other
1648	problems get reported tot he code that tries to use the result, not in a	2438	problems get reported to the code that tries to use the result, not in a
1649	random callback.	2439	random callback.
1650		2440
1651	All of this enables the following usage styles:	2441	All of this enables the following usage styles:
1652		2442
1653	1. Blocking:	2443	1. Blocking:
…		…
1701	through AnyEvent. The benchmark creates a lot of timers (with a zero	2491	through AnyEvent. The benchmark creates a lot of timers (with a zero
1702	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2492	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1703	which it is), lets them fire exactly once and destroys them again.	2493	which it is), lets them fire exactly once and destroys them again.
1704		2494
1705	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2495	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1706	distribution.	2496	distribution. It uses the L<AE> interface, which makes a real difference
		2497	for the EV and Perl backends only.
1707		2498
1708	=head3 Explanation of the columns	2499	=head3 Explanation of the columns
1709		2500
1710	I<watcher> is the number of event watchers created/destroyed. Since	2501	I<watcher> is the number of event watchers created/destroyed. Since
1711	different event models feature vastly different performances, each event	2502	different event models feature vastly different performances, each event
…		…
1732	watcher.	2523	watcher.
1733		2524
1734	=head3 Results	2525	=head3 Results
1735		2526
1736	name watchers bytes create invoke destroy comment	2527	name watchers bytes create invoke destroy comment
1737	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2528	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1738	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2529	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1739	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2530	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1740	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2531	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1741	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2532	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1742	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2533	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1743	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2534	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1744	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2535	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1745	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2536	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1746	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2537	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1747	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2538	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1748	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2539	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1749		2540
1750	=head3 Discussion	2541	=head3 Discussion
1751		2542
1752	The benchmark does I<not> measure scalability of the event loop very	2543	The benchmark does I<not> measure scalability of the event loop very
1753	well. For example, a select-based event loop (such as the pure perl one)	2544	well. For example, a select-based event loop (such as the pure perl one)
…		…
1765	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2556	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1766	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2557	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1767	cycles with POE.	2558	cycles with POE.
1768		2559
1769	C<EV> is the sole leader regarding speed and memory use, which are both	2560	C<EV> is the sole leader regarding speed and memory use, which are both
1770	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2561	maximal/minimal, respectively. When using the L<AE> API there is zero
		2562	overhead (when going through the AnyEvent API create is about 5-6 times
		2563	slower, with other times being equal, so still uses far less memory than
1771	far less memory than any other event loop and is still faster than Event	2564	any other event loop and is still faster than Event natively).
1772	natively.
1773		2565
1774	The pure perl implementation is hit in a few sweet spots (both the	2566	The pure perl implementation is hit in a few sweet spots (both the
1775	constant timeout and the use of a single fd hit optimisations in the perl	2567	constant timeout and the use of a single fd hit optimisations in the perl
1776	interpreter and the backend itself). Nevertheless this shows that it	2568	interpreter and the backend itself). Nevertheless this shows that it
1777	adds very little overhead in itself. Like any select-based backend its	2569	adds very little overhead in itself. Like any select-based backend its
…		…
1825	(even when used without AnyEvent), but most event loops have acceptable	2617	(even when used without AnyEvent), but most event loops have acceptable
1826	performance with or without AnyEvent.	2618	performance with or without AnyEvent.
1827		2619
1828	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2620	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1829	the actual event loop, only with extremely fast event loops such as EV	2621	the actual event loop, only with extremely fast event loops such as EV
1830	adds AnyEvent significant overhead.	2622	does AnyEvent add significant overhead.
1831		2623
1832	=item * You should avoid POE like the plague if you want performance or	2624	=item * You should avoid POE like the plague if you want performance or
1833	reasonable memory usage.	2625	reasonable memory usage.
1834		2626
1835	=back	2627	=back
…		…
1851	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2643	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1852	(1%) are active. This mirrors the activity of large servers with many	2644	(1%) are active. This mirrors the activity of large servers with many
1853	connections, most of which are idle at any one point in time.	2645	connections, most of which are idle at any one point in time.
1854		2646
1855	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2647	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1856	distribution.	2648	distribution. It uses the L<AE> interface, which makes a real difference
		2649	for the EV and Perl backends only.
1857		2650
1858	=head3 Explanation of the columns	2651	=head3 Explanation of the columns
1859		2652
1860	I<sockets> is the number of sockets, and twice the number of "servers" (as	2653	I<sockets> is the number of sockets, and twice the number of "servers" (as
1861	each server has a read and write socket end).	2654	each server has a read and write socket end).
…		…
1869	a new one that moves the timeout into the future.	2662	a new one that moves the timeout into the future.
1870		2663
1871	=head3 Results	2664	=head3 Results
1872		2665
1873	name sockets create request	2666	name sockets create request
1874	EV 20000 69.01 11.16	2667	EV 20000 62.66 7.99
1875	Perl 20000 73.32 35.87	2668	Perl 20000 68.32 32.64
1876	IOAsync 20000 157.00 98.14 epoll	2669	IOAsync 20000 174.06 101.15 epoll
1877	IOAsync 20000 159.31 616.06 poll	2670	IOAsync 20000 174.67 610.84 poll
1878	Event 20000 212.62 257.32	2671	Event 20000 202.69 242.91
1879	Glib 20000 651.16 1896.30	2672	Glib 20000 557.01 1689.52
1880	POE 20000 349.67 12317.24 uses POE::Loop::Event	2673	POE 20000 341.54 12086.32 uses POE::Loop::Event
1881		2674
1882	=head3 Discussion	2675	=head3 Discussion
1883		2676
1884	This benchmark I<does> measure scalability and overall performance of the	2677	This benchmark I<does> measure scalability and overall performance of the
1885	particular event loop.	2678	particular event loop.
…		…
2011	As you can see, the AnyEvent + EV combination even beats the	2804	As you can see, the AnyEvent + EV combination even beats the
2012	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2805	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2013	backend easily beats IO::Lambda and POE.	2806	backend easily beats IO::Lambda and POE.
2014		2807
2015	And even the 100% non-blocking version written using the high-level (and	2808	And even the 100% non-blocking version written using the high-level (and
2016	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2809	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2017	large margin, even though it does all of DNS, tcp-connect and socket I/O	2810	higher level ("unoptimised") abstractions by a large margin, even though
2018	in a non-blocking way.	2811	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2019		2812
2020	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2813	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2021	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2814	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2022	part of the IO::lambda distribution and were used without any changes.	2815	part of the IO::Lambda distribution and were used without any changes.
2023		2816
2024		2817
2025	=head1 SIGNALS	2818	=head1 SIGNALS
2026		2819
2027	AnyEvent currently installs handlers for these signals:	2820	AnyEvent currently installs handlers for these signals:
…		…
2032		2825
2033	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2826	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2034	emulation for event loops that do not support them natively. Also, some	2827	emulation for event loops that do not support them natively. Also, some
2035	event loops install a similar handler.	2828	event loops install a similar handler.
2036		2829
2037	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2830	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2038	reset it to default, to avoid losing child exit statuses.	2831	AnyEvent will reset it to default, to avoid losing child exit statuses.
2039		2832
2040	=item SIGPIPE	2833	=item SIGPIPE
2041		2834
2042	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2835	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2043	when AnyEvent gets loaded.	2836	when AnyEvent gets loaded.
…		…
2061	if $SIG{CHLD} eq 'IGNORE';	2854	if $SIG{CHLD} eq 'IGNORE';
2062		2855
2063	$SIG{PIPE} = sub { }	2856	$SIG{PIPE} = sub { }
2064	unless defined $SIG{PIPE};	2857	unless defined $SIG{PIPE};
2065		2858
		2859	=head1 RECOMMENDED/OPTIONAL MODULES
		2860
		2861	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2862	its built-in modules) are required to use it.
		2863
		2864	That does not mean that AnyEvent won't take advantage of some additional
		2865	modules if they are installed.
		2866
		2867	This section explains which additional modules will be used, and how they
		2868	affect AnyEvent's operation.
		2869
		2870	=over 4
		2871
		2872	=item L<Async::Interrupt>
		2873
		2874	This slightly arcane module is used to implement fast signal handling: To
		2875	my knowledge, there is no way to do completely race-free and quick
		2876	signal handling in pure perl. To ensure that signals still get
		2877	delivered, AnyEvent will start an interval timer to wake up perl (and
		2878	catch the signals) with some delay (default is 10 seconds, look for
		2879	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2880
		2881	If this module is available, then it will be used to implement signal
		2882	catching, which means that signals will not be delayed, and the event loop
		2883	will not be interrupted regularly, which is more efficient (and good for
		2884	battery life on laptops).
		2885
		2886	This affects not just the pure-perl event loop, but also other event loops
		2887	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2888
		2889	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2890	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2891	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2892	does nothing for those backends.
		2893
		2894	=item L<EV>
		2895
		2896	This module isn't really "optional", as it is simply one of the backend
		2897	event loops that AnyEvent can use. However, it is simply the best event
		2898	loop available in terms of features, speed and stability: It supports
		2899	the AnyEvent API optimally, implements all the watcher types in XS, does
		2900	automatic timer adjustments even when no monotonic clock is available,
		2901	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2902	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2903	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2904
		2905	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2906	then this module will do nothing for you.
		2907
		2908	=item L<Guard>
		2909
		2910	The guard module, when used, will be used to implement
		2911	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2912	lot less memory), but otherwise doesn't affect guard operation much. It is
		2913	purely used for performance.
		2914
		2915	=item L<JSON> and L<JSON::XS>
		2916
		2917	One of these modules is required when you want to read or write JSON data
		2918	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2919	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2920
		2921	=item L<Net::SSLeay>
		2922
		2923	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2924	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2925	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2926
		2927	=item L<Time::HiRes>
		2928
		2929	This module is part of perl since release 5.008. It will be used when the
		2930	chosen event library does not come with a timing source of its own. The
		2931	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2932	try to use a monotonic clock for timing stability.
		2933
		2934	=back
		2935
		2936
2066	=head1 FORK	2937	=head1 FORK
2067		2938
2068	Most event libraries are not fork-safe. The ones who are usually are	2939	Most event libraries are not fork-safe. The ones who are usually are
2069	because they rely on inefficient but fork-safe C<select> or C<poll>	2940	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2070	calls. Only L<EV> is fully fork-aware.	2941	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2942	are usually badly thought-out hacks that are incompatible with fork in
		2943	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2944	continue event-processing in both parent and child (or both, if you know
		2945	what you are doing).
		2946
		2947	This means that, in general, you cannot fork and do event processing in
		2948	the child if the event library was initialised before the fork (which
		2949	usually happens when the first AnyEvent watcher is created, or the library
		2950	is loaded).
2071		2951
2072	If you have to fork, you must either do so I<before> creating your first	2952	If you have to fork, you must either do so I<before> creating your first
2073	watcher OR you must not use AnyEvent at all in the child.	2953	watcher OR you must not use AnyEvent at all in the child OR you must do
		2954	something completely out of the scope of AnyEvent.
		2955
		2956	The problem of doing event processing in the parent I<and> the child
		2957	is much more complicated: even for backends that I<are> fork-aware or
		2958	fork-safe, their behaviour is not usually what you want: fork clones all
		2959	watchers, that means all timers, I/O watchers etc. are active in both
		2960	parent and child, which is almost never what you want. USing C<exec>
		2961	to start worker children from some kind of manage rprocess is usually
		2962	preferred, because it is much easier and cleaner, at the expense of having
		2963	to have another binary.
2074		2964
2075		2965
2076	=head1 SECURITY CONSIDERATIONS	2966	=head1 SECURITY CONSIDERATIONS
2077		2967
2078	AnyEvent can be forced to load any event model via	2968	AnyEvent can be forced to load any event model via
…		…
2108	pronounced).	2998	pronounced).
2109		2999
2110		3000
2111	=head1 SEE ALSO	3001	=head1 SEE ALSO
2112		3002
2113	Utility functions: L<AnyEvent::Util>.	3003	Tutorial/Introduction: L<AnyEvent::Intro>.
2114		3004
2115	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	3005	FAQ: L<AnyEvent::FAQ>.
2116	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	3006
		3007	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		3008	(simply logging).
		3009
		3010	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		3011	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		3012
		3013	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		3014	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		3015	L<Qt>, L<POE>, L<FLTK>.
2117		3016
2118	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3017	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2119	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3018	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2120	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3019	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2121	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	3020	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3021	L<AnyEvent::Impl::FLTK>.
2122		3022
2123	Non-blocking file handles, sockets, TCP clients and	3023	Non-blocking handles, pipes, stream sockets, TCP clients and
2124	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3024	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2125		3025
		3026	Asynchronous File I/O: L<AnyEvent::IO>.
		3027
2126	Asynchronous DNS: L<AnyEvent::DNS>.	3028	Asynchronous DNS: L<AnyEvent::DNS>.
2127		3029
2128	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3030	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2129	L<Coro::Event>,
2130		3031
2131	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3032	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2132	L<AnyEvent::HTTP>.	3033	L<AnyEvent::HTTP>.
2133		3034
2134		3035
2135	=head1 AUTHOR	3036	=head1 AUTHOR
2136		3037
2137	Marc Lehmann <schmorp@schmorp.de>	3038	Marc Lehmann <schmorp@schmorp.de>
2138	http://home.schmorp.de/	3039	http://anyevent.schmorp.de
2139		3040
2140	=cut	3041	=cut
2141		3042
2142	1	3043	1
2143		3044

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