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Revision 1.388 by root, Sun Oct 2 01:22:01 2011 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	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
368		403
369	This watcher might use C<%SIG> (depending on the event loop used),	404	This watcher might use C<%SIG> (depending on the event loop used),
370	so programs overwriting those signals directly will likely not work	405	so programs overwriting those signals directly will likely not work
371	correctly.	406	correctly.
372		407
373	Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not
374	support attaching callbacks to signals, which is a pity, as you cannot do
375	race-free signal handling in perl. AnyEvent will try to do it's best, but
376	in some cases, signals will be delayed. The maximum time a signal might
377	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
378	seconds). This variable can be changed only before the first signal
379	watcher is created, and should be left alone otherwise. Higher values
380	will cause fewer spurious wake-ups, which is better for power and CPU
381	saving. All these problems can be avoided by installing the optional
382	L<Async::Interrupt> module.
383
384	Example: exit on SIGINT	408	Example: exit on SIGINT
385		409
386	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
387		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
		432	attaching callbacks to signals in a generic way, which is a pity,
		433	as you cannot do race-free signal handling in perl, requiring
		434	C libraries for this. AnyEvent will try to do its best, which
		435	means in some cases, signals will be delayed. The maximum time
		436	a signal might be delayed is 10 seconds by default, but can
		437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
		438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the Ö<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
388	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
389		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
390	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.
391		452
392	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,
393	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
394	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
395	any trace events (stopped/continued).	456	finished and an exit status is available, not on any trace events
		457	(stopped/continued).
396		458
397	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
398	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
399	callback arguments.	461	callback arguments.
400		462
…		…
418	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
419	watcher before you C<fork> the child (alternatively, you can call	481	watcher before you C<fork> the child (alternatively, you can call
420	C<AnyEvent::detect>).	482	C<AnyEvent::detect>).
421		483
422	As most event loops do not support waiting for child events, they will be	484	As most event loops do not support waiting for child events, they will be
423	emulated by AnyEvent in most cases, in which the latency and race problems	485	emulated by AnyEvent in most cases, in which case the latency and race
424	mentioned in the description of signal watchers apply.	486	problems mentioned in the description of signal watchers apply.
425		487
426	Example: fork a process and wait for it	488	Example: fork a process and wait for it
427		489
428	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
429		491
…		…
441	# do something else, then wait for process exit	503	# do something else, then wait for process exit
442	$done->recv;	504	$done->recv;
443		505
444	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
445		507
446	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
447	to do it instantly, but only when there is nothing better to do. This
448	"nothing better to do" is usually defined to be "no other events need
449	attention by the event loop".
450		509
451	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
452	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.
453	events. Instead of blocking, the idle watcher is invoked.
454		512
455	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
456	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
457	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
458		525
459	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
460	program is otherwise idle:	527	program is otherwise idle:
…		…
476	});	543	});
477	});	544	});
478		545
479	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
480		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
481	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
482	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
483	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
484		556
485	AnyEvent is slightly different: it expects somebody else to run the event	557	AnyEvent is slightly different: it expects somebody else to run the event
486	loop and 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).
487		559
488	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
489	because they represent a condition that must become true.	561	they represent a condition that must become true.
490		562
491	Now is probably a good time to look at the examples further below.	563	Now is probably a good time to look at the examples further below.
492		564
493	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
494	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
…		…
499	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
500	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
501	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<<
502	->send >> method).	574	->send >> method).
503		575
504	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
505	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:
506	in time where multiple outstanding events have been processed. And yet	578
507	another way to call them is transactions - each condition variable can be	579	=over 4
508	used to represent a transaction, which finishes at some point and delivers	580
509	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
510		599
511	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
512	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,
513	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
514	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
…		…
527		616
528	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
529	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
530	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
531	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
532	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
533		622
534	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
535	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
536	for the send to occur.	625	for the send to occur.
537		626
538	Example: wait for a timer.	627	Example: wait for a timer.
539		628
540	# wait till the result is ready	629	# condition: "wait till the timer is fired"
541	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
542		631
543	# do something such as adding a timer	632	# create the timer - we could wait for, say
544	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
545	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
546	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
547	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
548	after => 1,	637	after => 1,
549	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
550	);	639	);
551		640
552	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
553	# calls -<send	642	# calls ->send
554	$result_ready->recv;	643	$timer_fired->recv;
555		644
556	Example: wait for a timer, but take advantage of the fact that condition	645	Example: wait for a timer, but take advantage of the fact that condition
557	variables are also callable directly.	646	variables are also callable directly.
558		647
559	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
…		…
602	they were 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
603	C<send>.	692	C<send>.
604		693
605	=item $cv->croak ($error)	694	=item $cv->croak ($error)
606		695
607	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
608	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
609		698
610	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
611	user/consumer. Doing it this way instead of calling C<croak> directly	700	user/consumer. Doing it this way instead of calling C<croak> directly
612	delays the error detetcion, but has the overwhelmign advantage that it	701	delays the error detection, but has the overwhelming advantage that it
613	diagnoses the error at the place where the result is expected, and not	702	diagnoses the error at the place where the result is expected, and not
614	deep in some event clalback without connection to the actual code causing	703	deep in some event callback with no connection to the actual code causing
615	the problem.	704	the problem.
616		705
617	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
618		707
619	=item $cv->end	708	=item $cv->end
…		…
622	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
623	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
624		713
625	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
626	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
627	>>, 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
628	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
629	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.
630		720
631	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
632	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
633	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).
634		724
…		…
656	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
657	sending.	747	sending.
658		748
659	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
660	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
661	begung can potentially be zero:	751	begun can potentially be zero:
662		752
663	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
664		754
665	my %result;	755	my %result;
666	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
667		757
668	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
669	$cv->begin;	759	$cv->begin;
670	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
671	$result{$host} = ...;	761	$result{$host} = ...;
…		…
687	to be called once the counter reaches C<0>, and second, it ensures that	777	to be called once the counter reaches C<0>, and second, it ensures that
688	C<send> is called even when C<no> hosts are being pinged (the loop	778	C<send> is called even when C<no> hosts are being pinged (the loop
689	doesn't execute once).	779	doesn't execute once).
690		780
691	This is the general pattern when you "fan out" into multiple (but	781	This is the general pattern when you "fan out" into multiple (but
692	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
693	the callback and ensure C<end> is called at least once, and then, for each	783	the callback and ensure C<end> is called at least once, and then, for each
694	subrequest you start, call C<begin> and for each subrequest you finish,	784	subrequest you start, call C<begin> and for each subrequest you finish,
695	call C<end>.	785	call C<end>.
696		786
697	=back	787	=back
…		…
704	=over 4	794	=over 4
705		795
706	=item $cv->recv	796	=item $cv->recv
707		797
708	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
709	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
710	normally.	800	normally.
711		801
712	You can only wait once on a condition - additional calls are valid but	802	You can only wait once on a condition - additional calls are valid but
713	will return immediately.	803	will return immediately.
714		804
…		…
731	caller decide whether the call will block or not (for example, by coupling	821	caller decide whether the call will block or not (for example, by coupling
732	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
733	callbacks so the caller knows that getting the result will not block,	823	callbacks so the caller knows that getting the result will not block,
734	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
735		825
736	You can ensure that C<< -recv >> never blocks by setting a callback and	826	You can ensure that C<< ->recv >> never blocks by setting a callback and
737	only calling C<< ->recv >> from within that callback (or at a later	827	only calling C<< ->recv >> from within that callback (or at a later
738	time). This will work even when the event loop does not support blocking	828	time). This will work even when the event loop does not support blocking
739	waits otherwise.	829	waits otherwise.
740		830
741	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
747		837
748	This is a mutator function that returns the callback set and optionally	838	This is a mutator function that returns the callback set and optionally
749	replaces it before doing so.	839	replaces it before doing so.
750		840
751	The callback will be called when the condition becomes "true", i.e. when	841	The callback will be called when the condition becomes "true", i.e. when
752	C<send> or C<croak> are called, with the only argument being the condition	842	C<send> or C<croak> are called, with the only argument being the
753	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
754	is guaranteed not to block.	844	callback is called immediately when it is set. Calling C<recv> inside
		845	the callback or at any later time is guaranteed not to block.
755		846
756	=back	847	=back
757		848
758	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
759		850
…		…
762	=over 4	853	=over 4
763		854
764	=item Backends that are autoprobed when no other event loop can be found.	855	=item Backends that are autoprobed when no other event loop can be found.
765		856
766	EV is the preferred backend when no other event loop seems to be in	857	EV is the preferred backend when no other event loop seems to be in
767	use. If EV is not installed, then AnyEvent will try Event, and, failing	858	use. If EV is not installed, then AnyEvent will fall back to its own
768	that, will fall back to its own pure-perl implementation, which is	859	pure-perl implementation, which is available everywhere as it comes with
769	available everywhere as it comes with AnyEvent itself.	860	AnyEvent itself.
770		861
771	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
772	AnyEvent::Impl::Event based on Event, very stable, few glitches.
773	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	863	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
774		864
775	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
776		866
777	These will be used when they are currently loaded when the first watcher	867	These will be used if they are already loaded when the first watcher
778	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
779	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
780	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
781	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
782		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
783	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
784	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
785	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
786	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
		879	AnyEvent::Impl::IOAsync based on IO::Async.
		880	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		881	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
787		882
788	=item Backends with special needs.	883	=item Backends with special needs.
789		884
790	Qt requires the Qt::Application to be instantiated first, but will	885	Qt requires the Qt::Application to be instantiated first, but will
791	otherwise be picked up automatically. As long as the main program	886	otherwise be picked up automatically. As long as the main program
792	instantiates the application before any AnyEvent watchers are created,	887	instantiates the application before any AnyEvent watchers are created,
793	everything should just work.	888	everything should just work.
794		889
795	AnyEvent::Impl::Qt based on Qt.	890	AnyEvent::Impl::Qt based on Qt.
796		891
797	Support for IO::Async can only be partial, as it is too broken and
798	architecturally limited to even support the AnyEvent API. It also
799	is the only event loop that needs the loop to be set explicitly, so
800	it can only be used by a main program knowing about AnyEvent. See
801	L<AnyEvent::Impl::Async> for the gory details.
802
803	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
804
805	=item Event loops that are indirectly supported via other backends.	892	=item Event loops that are indirectly supported via other backends.
806		893
807	Some event loops can be supported via other modules:	894	Some event loops can be supported via other modules:
808		895
809	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	896	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
834	Contains C<undef> until the first watcher is being created, before the	921	Contains C<undef> until the first watcher is being created, before the
835	backend has been autodetected.	922	backend has been autodetected.
836		923
837	Afterwards it contains the event model that is being used, which is the	924	Afterwards it contains the event model that is being used, which is the
838	name of the Perl class implementing the model. This class is usually one	925	name of the Perl class implementing the model. This class is usually one
839	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	926	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
840	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	927	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
841	will be C<urxvt::anyevent>).	928	will be C<urxvt::anyevent>).
842		929
843	=item AnyEvent::detect	930	=item AnyEvent::detect
844		931
845	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	932	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
846	if necessary. You should only call this function right before you would	933	if necessary. You should only call this function right before you would
847	have created an AnyEvent watcher anyway, that is, as late as possible at	934	have created an AnyEvent watcher anyway, that is, as late as possible at
848	runtime, and not e.g. while initialising of your module.	935	runtime, and not e.g. during initialisation of your module.
		936
		937	The effect of calling this function is as if a watcher had been created
		938	(specifically, actions that happen "when the first watcher is created"
		939	happen when calling detetc as well).
849		940
850	If you need to do some initialisation before AnyEvent watchers are	941	If you need to do some initialisation before AnyEvent watchers are
851	created, use C<post_detect>.	942	created, use C<post_detect>.
852		943
853	=item $guard = AnyEvent::post_detect { BLOCK }	944	=item $guard = AnyEvent::post_detect { BLOCK }
854		945
855	Arranges for the code block to be executed as soon as the event model is	946	Arranges for the code block to be executed as soon as the event model is
856	autodetected (or immediately if this has already happened).	947	autodetected (or immediately if that has already happened).
857		948
858	The block will be executed I<after> the actual backend has been detected	949	The block will be executed I<after> the actual backend has been detected
859	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	950	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
860	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	951	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
861	other initialisations - see the sources of L<AnyEvent::Strict> or	952	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
865	event module detection too early, for example, L<AnyEvent::AIO> creates	956	event module detection too early, for example, L<AnyEvent::AIO> creates
866	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	957	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
867	avoid autodetecting the event module at load time.	958	avoid autodetecting the event module at load time.
868		959
869	If called in scalar or list context, then it creates and returns an object	960	If called in scalar or list context, then it creates and returns an object
870	that automatically removes the callback again when it is destroyed. See	961	that automatically removes the callback again when it is destroyed (or
		962	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
871	L<Coro::BDB> for a case where this is useful.	963	a case where this is useful.
		964
		965	Example: Create a watcher for the IO::AIO module and store it in
		966	C<$WATCHER>, but do so only do so after the event loop is initialised.
		967
		968	our WATCHER;
		969
		970	my $guard = AnyEvent::post_detect {
		971	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		972	};
		973
		974	# the ||= is important in case post_detect immediately runs the block,
		975	# as to not clobber the newly-created watcher. assigning both watcher and
		976	# post_detect guard to the same variable has the advantage of users being
		977	# able to just C<undef $WATCHER> if the watcher causes them grief.
		978
		979	$WATCHER ||= $guard;
872		980
873	=item @AnyEvent::post_detect	981	=item @AnyEvent::post_detect
874		982
875	If there are any code references in this array (you can C<push> to it	983	If there are any code references in this array (you can C<push> to it
876	before or after loading AnyEvent), then they will called directly after	984	before or after loading AnyEvent), then they will be called directly
877	the event loop has been chosen.	985	after the event loop has been chosen.
878		986
879	You should check C<$AnyEvent::MODEL> before adding to this array, though:	987	You should check C<$AnyEvent::MODEL> before adding to this array, though:
880	if it is defined then the event loop has already been detected, and the	988	if it is defined then the event loop has already been detected, and the
881	array will be ignored.	989	array will be ignored.
882		990
883	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	991	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
884	it,as it takes care of these details.	992	it, as it takes care of these details.
885		993
886	This variable is mainly useful for modules that can do something useful	994	This variable is mainly useful for modules that can do something useful
887	when AnyEvent is used and thus want to know when it is initialised, but do	995	when AnyEvent is used and thus want to know when it is initialised, but do
888	not need to even load it by default. This array provides the means to hook	996	not need to even load it by default. This array provides the means to hook
889	into AnyEvent passively, without loading it.	997	into AnyEvent passively, without loading it.
890		998
		999	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1000	together, you could put this into Coro (this is the actual code used by
		1001	Coro to accomplish this):
		1002
		1003	if (defined $AnyEvent::MODEL) {
		1004	# AnyEvent already initialised, so load Coro::AnyEvent
		1005	require Coro::AnyEvent;
		1006	} else {
		1007	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1008	# as soon as it is
		1009	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1010	}
		1011
		1012	=item AnyEvent::postpone { BLOCK }
		1013
		1014	Arranges for the block to be executed as soon as possible, but not before
		1015	the call itself returns. In practise, the block will be executed just
		1016	before the event loop polls for new events, or shortly afterwards.
		1017
		1018	This function never returns anything (to make the C<return postpone { ...
		1019	}> idiom more useful.
		1020
		1021	To understand the usefulness of this function, consider a function that
		1022	asynchronously does something for you and returns some transaction
		1023	object or guard to let you cancel the operation. For example,
		1024	C<AnyEvent::Socket::tcp_connect>:
		1025
		1026	# start a conenction attempt unless one is active
		1027	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1028	delete $self->{connect_guard};
		1029	...
		1030	};
		1031
		1032	Imagine that this function could instantly call the callback, for
		1033	example, because it detects an obvious error such as a negative port
		1034	number. Invoking the callback before the function returns causes problems
		1035	however: the callback will be called and will try to delete the guard
		1036	object. But since the function hasn't returned yet, there is nothing to
		1037	delete. When the function eventually returns it will assign the guard
		1038	object to C<< $self->{connect_guard} >>, where it will likely never be
		1039	deleted, so the program thinks it is still trying to connect.
		1040
		1041	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1042	callback directly on error:
		1043
		1044	$cb->(undef), return # signal error to callback, BAD!
		1045	if $some_error_condition;
		1046
		1047	It should use C<postpone>:
		1048
		1049	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1050	if $some_error_condition;
		1051
		1052	=item AnyEvent::log $level, $msg[, @args]
		1053
		1054	Log the given C<$msg> at the given C<$level>.
		1055
		1056	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1057	to see whether the message will be logged. If the test succeeds it will
		1058	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1059	the L<AnyEvent::Log> documentation for details.
		1060
		1061	If the test fails it will simply return. Right now this happens when a
		1062	numerical loglevel is used and it is larger than the level specified via
		1063	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1064
		1065	If you want to sprinkle loads of logging calls around your code, consider
		1066	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1067	which can reduce typing, codesize and can reduce the logging overhead
		1068	enourmously.
		1069
891	=back	1070	=back
892		1071
893	=head1 WHAT TO DO IN A MODULE	1072	=head1 WHAT TO DO IN A MODULE
894		1073
895	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1074	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
905	because it will stall the whole program, and the whole point of using	1084	because it will stall the whole program, and the whole point of using
906	events is to stay interactive.	1085	events is to stay interactive.
907		1086
908	It is fine, however, to call C<< ->recv >> when the user of your module	1087	It is fine, however, to call C<< ->recv >> when the user of your module
909	requests it (i.e. if you create a http request object ad have a method	1088	requests it (i.e. if you create a http request object ad have a method
910	called C<results> that returns the results, it should call C<< ->recv >>	1089	called C<results> that returns the results, it may call C<< ->recv >>
911	freely, as the user of your module knows what she is doing. always).	1090	freely, as the user of your module knows what she is doing. Always).
912		1091
913	=head1 WHAT TO DO IN THE MAIN PROGRAM	1092	=head1 WHAT TO DO IN THE MAIN PROGRAM
914		1093
915	There will always be a single main program - the only place that should	1094	There will always be a single main program - the only place that should
916	dictate which event model to use.	1095	dictate which event model to use.
917		1096
918	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1097	If the program is not event-based, it need not do anything special, even
919	do anything special (it does not need to be event-based) and let AnyEvent	1098	when it depends on a module that uses an AnyEvent. If the program itself
920	decide which implementation to chose if some module relies on it.	1099	uses AnyEvent, but does not care which event loop is used, all it needs
		1100	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1101	available loop implementation.
921		1102
922	If the main program relies on a specific event model - for example, in	1103	If the main program relies on a specific event model - for example, in
923	Gtk2 programs you have to rely on the Glib module - you should load the	1104	Gtk2 programs you have to rely on the Glib module - you should load the
924	event module before loading AnyEvent or any module that uses it: generally	1105	event module before loading AnyEvent or any module that uses it: generally
925	speaking, you should load it as early as possible. The reason is that	1106	speaking, you should load it as early as possible. The reason is that
926	modules might create watchers when they are loaded, and AnyEvent will	1107	modules might create watchers when they are loaded, and AnyEvent will
927	decide on the event model to use as soon as it creates watchers, and it	1108	decide on the event model to use as soon as it creates watchers, and it
928	might chose the wrong one unless you load the correct one yourself.	1109	might choose the wrong one unless you load the correct one yourself.
929		1110
930	You can chose to use a pure-perl implementation by loading the	1111	You can chose to use a pure-perl implementation by loading the
931	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1112	C<AnyEvent::Loop> module, which gives you similar behaviour
932	everywhere, but letting AnyEvent chose the model is generally better.	1113	everywhere, but letting AnyEvent chose the model is generally better.
933		1114
934	=head2 MAINLOOP EMULATION	1115	=head2 MAINLOOP EMULATION
935		1116
936	Sometimes (often for short test scripts, or even standalone programs who	1117	Sometimes (often for short test scripts, or even standalone programs who
…		…
949		1130
950		1131
951	=head1 OTHER MODULES	1132	=head1 OTHER MODULES
952		1133
953	The following is a non-exhaustive list of additional modules that use	1134	The following is a non-exhaustive list of additional modules that use
954	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1135	AnyEvent as a client and can therefore be mixed easily with other
955	modules and other event loops in the same program. Some of the modules	1136	AnyEvent modules and other event loops in the same program. Some of the
956	come with AnyEvent, most are available via CPAN.	1137	modules come as part of AnyEvent, the others are available via CPAN (see
		1138	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1139	a longer non-exhaustive list), and the list is heavily biased towards
		1140	modules of the AnyEvent author himself :)
957		1141
958	=over 4	1142	=over 4
959		1143
960	=item L<AnyEvent::Util>	1144	=item L<AnyEvent::Util>
961		1145
962	Contains various utility functions that replace often-used but blocking	1146	Contains various utility functions that replace often-used blocking
963	functions such as C<inet_aton> by event-/callback-based versions.	1147	functions such as C<inet_aton> with event/callback-based versions.
964		1148
965	=item L<AnyEvent::Socket>	1149	=item L<AnyEvent::Socket>
966		1150
967	Provides various utility functions for (internet protocol) sockets,	1151	Provides various utility functions for (internet protocol) sockets,
968	addresses and name resolution. Also functions to create non-blocking tcp	1152	addresses and name resolution. Also functions to create non-blocking tcp
…		…
970		1154
971	=item L<AnyEvent::Handle>	1155	=item L<AnyEvent::Handle>
972		1156
973	Provide read and write buffers, manages watchers for reads and writes,	1157	Provide read and write buffers, manages watchers for reads and writes,
974	supports raw and formatted I/O, I/O queued and fully transparent and	1158	supports raw and formatted I/O, I/O queued and fully transparent and
975	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1159	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
976		1160
977	=item L<AnyEvent::DNS>	1161	=item L<AnyEvent::DNS>
978		1162
979	Provides rich asynchronous DNS resolver capabilities.	1163	Provides rich asynchronous DNS resolver capabilities.
980		1164
		1165	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1166
		1167	Implement event-based interfaces to the protocols of the same name (for
		1168	the curious, IGS is the International Go Server and FCP is the Freenet
		1169	Client Protocol).
		1170
981	=item L<AnyEvent::HTTP>	1171	=item L<AnyEvent::AIO>
982		1172
983	A simple-to-use HTTP library that is capable of making a lot of concurrent	1173	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
984	HTTP requests.	1174	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1175	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1176	file I/O, and much more.
		1177
		1178	=item L<AnyEvent::Filesys::Notify>
		1179
		1180	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1181	path changes (e.g. "watch this directory for new files", "watch this
		1182	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1183	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1184	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1185	fall back to blocking scans at regular intervals transparently on other
		1186	platforms, so it's about as portable as it gets.
		1187
		1188	(I haven't used it myself, but I haven't heard anybody complaining about
		1189	it yet).
		1190
		1191	=item L<AnyEvent::DBI>
		1192
		1193	Executes L<DBI> requests asynchronously in a proxy process for you,
		1194	notifying you in an event-based way when the operation is finished.
985		1195
986	=item L<AnyEvent::HTTPD>	1196	=item L<AnyEvent::HTTPD>
987		1197
988	Provides a simple web application server framework.	1198	A simple embedded webserver.
989		1199
990	=item L<AnyEvent::FastPing>	1200	=item L<AnyEvent::FastPing>
991		1201
992	The fastest ping in the west.	1202	The fastest ping in the west.
993		1203
994	=item L<AnyEvent::DBI>
995
996	Executes L<DBI> requests asynchronously in a proxy process.
997
998	=item L<AnyEvent::AIO>
999
1000	Truly asynchronous I/O, should be in the toolbox of every event
1001	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1002	together.
1003
1004	=item L<AnyEvent::BDB>
1005
1006	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1007	L<BDB> and AnyEvent together.
1008
1009	=item L<AnyEvent::GPSD>
1010
1011	A non-blocking interface to gpsd, a daemon delivering GPS information.
1012
1013	=item L<AnyEvent::IRC>
1014
1015	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1016
1017	=item L<AnyEvent::XMPP>
1018
1019	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1020	Net::XMPP2>.
1021
1022	=item L<AnyEvent::IGS>
1023
1024	A non-blocking interface to the Internet Go Server protocol (used by
1025	L<App::IGS>).
1026
1027	=item L<Net::FCP>
1028
1029	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1030	of AnyEvent.
1031
1032	=item L<Event::ExecFlow>
1033
1034	High level API for event-based execution flow control.
1035
1036	=item L<Coro>	1204	=item L<Coro>
1037		1205
1038	Has special support for AnyEvent via L<Coro::AnyEvent>.	1206	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1207	to simply invert the flow control - don't call us, we will call you:
		1208
		1209	async {
		1210	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1211	print "5 seconds later!\n";
		1212
		1213	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1214	my $line = <STDIN>; # works for ttys
		1215
		1216	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1217	my ($body, $hdr) = Coro::rouse_wait;
		1218	};
1039		1219
1040	=back	1220	=back
1041		1221
1042	=cut	1222	=cut
1043		1223
1044	package AnyEvent;	1224	package AnyEvent;
1045		1225
1046	# basically a tuned-down version of common::sense	1226	# basically a tuned-down version of common::sense
1047	sub common_sense {	1227	sub common_sense {
1048	# no warnings	1228	# from common:.sense 3.4
1049	${^WARNING_BITS} ^= ${^WARNING_BITS};	1229	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1050	# use strict vars subs	1230	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1051	$^H |= 0x00000600;	1231	$^H |= 0x00000600;
1052	}	1232	}
1053		1233
1054	BEGIN { AnyEvent::common_sense }	1234	BEGIN { AnyEvent::common_sense }
1055		1235
1056	use Carp ();	1236	use Carp ();
1057		1237
1058	our $VERSION = 4.85;	1238	our $VERSION = '6.02';
1059	our $MODEL;	1239	our $MODEL;
1060
1061	our $AUTOLOAD;
1062	our @ISA;	1240	our @ISA;
1063
1064	our @REGISTRY;	1241	our @REGISTRY;
1065
1066	our $WIN32;
1067
1068	our $VERBOSE;	1242	our $VERBOSE;
		1243	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1244	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1069		1245
1070	BEGIN {	1246	BEGIN {
1071	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1247	require "AnyEvent/constants.pl";
		1248
1072	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1249	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1073		1250
1074	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1251	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1075	if ${^TAINT};	1252	if ${^TAINT};
1076		1253
1077	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1254	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1255	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1078		1256
1079	}	1257	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1258	if ${^TAINT};
1080		1259
1081	our $MAX_SIGNAL_LATENCY = 10;	1260	# $ENV{PERL_ANYEVENT_xxx} now valid
1082		1261
1083	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1262	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1084		1263
1085	{
1086	my $idx;	1264	my $idx;
1087	$PROTOCOL{$_} = ++$idx	1265	$PROTOCOL{$_} = ++$idx
1088	for reverse split /\s*,\s*/,	1266	for reverse split /\s*,\s*/,
1089	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1267	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1090	}	1268	}
1091		1269
		1270	our @post_detect;
		1271
		1272	sub post_detect(&) {
		1273	my ($cb) = @_;
		1274
		1275	push @post_detect, $cb;
		1276
		1277	defined wantarray
		1278	? bless \$cb, "AnyEvent::Util::postdetect"
		1279	: ()
		1280	}
		1281
		1282	sub AnyEvent::Util::postdetect::DESTROY {
		1283	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1284	}
		1285
		1286	our $POSTPONE_W;
		1287	our @POSTPONE;
		1288
		1289	sub _postpone_exec {
		1290	undef $POSTPONE_W;
		1291
		1292	&{ shift @POSTPONE }
		1293	while @POSTPONE;
		1294	}
		1295
		1296	sub postpone(&) {
		1297	push @POSTPONE, shift;
		1298
		1299	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1300
		1301	()
		1302	}
		1303
		1304	sub log($$;@) {
		1305	# only load the big bloated module when we actually are about to log something
		1306	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1307	local ($!, $@);
		1308	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1309	# AnyEvent::Log overwrites this function
		1310	goto &log;
		1311	}
		1312
		1313	0 # not logged
		1314	}
		1315
		1316	sub logger($;$) {
		1317	package AnyEvent::Log;
		1318
		1319	my ($level, $renabled) = @_;
		1320
		1321	$$renabled = $level <= $VERBOSE;
		1322
		1323	my $pkg = (caller)[0];
		1324
		1325	my $logger = [$pkg, $level, $renabled];
		1326
		1327	our %LOGGER;
		1328	$LOGGER{$logger+0} = $logger;
		1329
		1330	return unless defined wantarray;
		1331
		1332	require AnyEvent::Util;
		1333	my $guard = AnyEvent::Util::guard (sub {
		1334	# "clean up"
		1335	delete $LOGGER{$logger+0};
		1336	});
		1337
		1338	sub {
		1339	return 0 unless $$renabled;
		1340
		1341	$guard if 0; # keep guard alive, but don't cause runtime overhead
		1342	require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1343	package AnyEvent::Log;
		1344	_log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1345	}
		1346	}
		1347
		1348	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1349	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1350	}
		1351
1092	my @models = (	1352	our @models = (
1093	[EV:: => AnyEvent::Impl::EV::],	1353	[EV:: => AnyEvent::Impl::EV::],
1094	[Event:: => AnyEvent::Impl::Event::],
1095	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1354	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1096	# everything below here will not be autoprobed	1355	# everything below here will not (normally) be autoprobed
1097	# as the pureperl backend should work everywhere	1356	# as the pure perl backend should work everywhere
1098	# and is usually faster	1357	# and is usually faster
		1358	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
		1359	[Event:: => AnyEvent::Impl::Event::], # slow, stable
1099	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1360	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1361	# everything below here should not be autoloaded
1100	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1362	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1101	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1363	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1102	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1364	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1103	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1365	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1104	[Wx:: => AnyEvent::Impl::POE::],	1366	[Wx:: => AnyEvent::Impl::POE::],
1105	[Prima:: => AnyEvent::Impl::POE::],	1367	[Prima:: => AnyEvent::Impl::POE::],
1106	# IO::Async is just too broken - we would need workarounds for its	1368	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1107	# byzantine signal and broken child handling, among others.	1369	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1108	# IO::Async is rather hard to detect, as it doesn't have any	1370	[FLTK:: => AnyEvent::Impl::FLTK::],
1109	# obvious default class.
1110	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1111	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1112	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1113	);	1371	);
1114		1372
1115	our %method = map +($_ => 1),	1373	our @isa_hook;
		1374
		1375	sub _isa_set {
		1376	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1377
		1378	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1379	for 1 .. $#pkg;
		1380
		1381	grep $_ && $_->[1], @isa_hook
		1382	and AE::_reset ();
		1383	}
		1384
		1385	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1386	sub _isa_hook($$;$) {
		1387	my ($i, $pkg, $reset_ae) = @_;
		1388
		1389	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1390
		1391	_isa_set;
		1392	}
		1393
		1394	# all autoloaded methods reserve the complete glob, not just the method slot.
		1395	# due to bugs in perls method cache implementation.
1116	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1396	our @methods = qw(io timer time now now_update signal child idle condvar);
1117		1397
1118	our @post_detect;
1119
1120	sub post_detect(&) {	1398	sub detect() {
1121	my ($cb) = @_;	1399	return $MODEL if $MODEL; # some programs keep references to detect
1122		1400
1123	if ($MODEL) {	1401	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1124	$cb->();	1402	# the author knows about the problems and what it does to AnyEvent as a whole
		1403	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1404	# anyway.
		1405	AnyEvent::log fatal => "AnyEvent: IO::Async::Loop::AnyEvent detected - this module is broken by design,\n"
		1406	. "abuses internals and breaks AnyEvent, will not continue."
		1407	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1125		1408
1126	1	1409	local $!; # for good measure
		1410	local $SIG{__DIE__}; # we use eval
		1411
		1412	# free some memory
		1413	*detect = sub () { $MODEL };
		1414	# undef &func doesn't correctly update the method cache. grmbl.
		1415	# so we delete the whole glob. grmbl.
		1416	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1417	# a glob with an active sub. hrm. i hope it works, but perl is
		1418	# usually buggy in this department. sigh.
		1419	delete @{"AnyEvent::"}{@methods};
		1420	undef @methods;
		1421
		1422	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1423	my $model = $1;
		1424	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1425	if (eval "require $model") {
		1426	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1427	$MODEL = $model;
1127	} else {	1428	} else {
1128	push @post_detect, $cb;	1429	AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1129		1430	}
1130	defined wantarray
1131	? bless \$cb, "AnyEvent::Util::postdetect"
1132	: ()
1133	}	1431	}
1134	}
1135		1432
1136	sub AnyEvent::Util::postdetect::DESTROY {	1433	# check for already loaded models
1137	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1138	}
1139
1140	sub detect() {
1141	unless ($MODEL) {	1434	unless ($MODEL) {
1142	local $SIG{__DIE__};	1435	for (@REGISTRY, @models) {
1143		1436	my ($package, $model) = @$_;
1144	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1437	if (${"$package\::VERSION"} > 0) {
1145	my $model = "AnyEvent::Impl::$1";
1146	if (eval "require $model") {	1438	if (eval "require $model") {
		1439	AnyEvent::log 7 => "autodetected model '$model', using it.";
1147	$MODEL = $model;	1440	$MODEL = $model;
1148	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1441	last;
1149	} else {	1442	}
1150	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1151	}	1443	}
1152	}	1444	}
1153		1445
1154	# check for already loaded models
1155	unless ($MODEL) {	1446	unless ($MODEL) {
		1447	# try to autoload a model
1156	for (@REGISTRY, @models) {	1448	for (@REGISTRY, @models) {
1157	my ($package, $model) = @$_;	1449	my ($package, $model) = @$_;
		1450	if (
		1451	eval "require $package"
1158	if (${"$package\::VERSION"} > 0) {	1452	and ${"$package\::VERSION"} > 0
1159	if (eval "require $model") {	1453	and eval "require $model"
		1454	) {
		1455	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1160	$MODEL = $model;	1456	$MODEL = $model;
1161	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1162	last;	1457	last;
1163	}
1164	}	1458	}
1165	}	1459	}
1166		1460
1167	unless ($MODEL) {
1168	# try to load a model
1169
1170	for (@REGISTRY, @models) {
1171	my ($package, $model) = @$_;
1172	if (eval "require $package"
1173	and ${"$package\::VERSION"} > 0
1174	and eval "require $model") {
1175	$MODEL = $model;
1176	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1177	last;
1178	}
1179	}
1180
1181	$MODEL	1461	$MODEL
1182	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1462	or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1183	}
1184	}	1463	}
1185
1186	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1187
1188	unshift @ISA, $MODEL;
1189
1190	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1191
1192	(shift @post_detect)->() while @post_detect;
1193	}	1464	}
1194		1465
		1466	# free memory only needed for probing
		1467	undef @models;
		1468	undef @REGISTRY;
		1469
		1470	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1471
		1472	# now nuke some methods that are overridden by the backend.
		1473	# SUPER usage is not allowed in these.
		1474	for (qw(time signal child idle)) {
		1475	undef &{"AnyEvent::Base::$_"}
		1476	if defined &{"$MODEL\::$_"};
		1477	}
		1478
		1479	_isa_set;
		1480
		1481	# we're officially open!
		1482
		1483	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1484	require AnyEvent::Strict;
		1485	}
		1486
		1487	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1488	require AnyEvent::Debug;
		1489	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1490	}
		1491
		1492	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1493	require AnyEvent::Socket;
		1494	require AnyEvent::Debug;
		1495
		1496	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1497	$shell =~ s/\$\$/$$/g;
		1498
		1499	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1500	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1501	}
		1502
		1503	# now the anyevent environment is set up as the user told us to, so
		1504	# call the actual user code - post detects
		1505
		1506	(shift @post_detect)->() while @post_detect;
		1507	undef @post_detect;
		1508
		1509	*post_detect = sub(&) {
		1510	shift->();
		1511
		1512	undef
		1513	};
		1514
1195	$MODEL	1515	$MODEL
1196	}	1516	}
1197		1517
1198	sub AUTOLOAD {	1518	for my $name (@methods) {
1199	(my $func = $AUTOLOAD) =~ s/.*://;	1519	*$name = sub {
1200		1520	detect;
1201	$method{$func}	1521	# we use goto because
1202	or Carp::croak "$func: not a valid method for AnyEvent objects";	1522	# a) it makes the thunk more transparent
1203		1523	# b) it allows us to delete the thunk later
1204	detect unless $MODEL;	1524	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1205		1525	};
1206	my $class = shift;
1207	$class->$func (@_);
1208	}	1526	}
1209		1527
1210	# utility function to dup a filehandle. this is used by many backends	1528	# utility function to dup a filehandle. this is used by many backends
1211	# to support binding more than one watcher per filehandle (they usually	1529	# to support binding more than one watcher per filehandle (they usually
1212	# allow only one watcher per fd, so we dup it to get a different one).	1530	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1222	# we assume CLOEXEC is already set by perl in all important cases	1540	# we assume CLOEXEC is already set by perl in all important cases
1223		1541
1224	($fh2, $rw)	1542	($fh2, $rw)
1225	}	1543	}
1226		1544
		1545	=head1 SIMPLIFIED AE API
		1546
		1547	Starting with version 5.0, AnyEvent officially supports a second, much
		1548	simpler, API that is designed to reduce the calling, typing and memory
		1549	overhead by using function call syntax and a fixed number of parameters.
		1550
		1551	See the L<AE> manpage for details.
		1552
		1553	=cut
		1554
		1555	package AE;
		1556
		1557	our $VERSION = $AnyEvent::VERSION;
		1558
		1559	sub _reset() {
		1560	eval q{
		1561	# fall back to the main API by default - backends and AnyEvent::Base
		1562	# implementations can overwrite these.
		1563
		1564	sub io($$$) {
		1565	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1566	}
		1567
		1568	sub timer($$$) {
		1569	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1570	}
		1571
		1572	sub signal($$) {
		1573	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1574	}
		1575
		1576	sub child($$) {
		1577	AnyEvent->child (pid => $_[0], cb => $_[1])
		1578	}
		1579
		1580	sub idle($) {
		1581	AnyEvent->idle (cb => $_[0]);
		1582	}
		1583
		1584	sub cv(;&) {
		1585	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1586	}
		1587
		1588	sub now() {
		1589	AnyEvent->now
		1590	}
		1591
		1592	sub now_update() {
		1593	AnyEvent->now_update
		1594	}
		1595
		1596	sub time() {
		1597	AnyEvent->time
		1598	}
		1599
		1600	*postpone = \&AnyEvent::postpone;
		1601	*log = \&AnyEvent::log;
		1602	};
		1603	die if $@;
		1604	}
		1605
		1606	BEGIN { _reset }
		1607
1227	package AnyEvent::Base;	1608	package AnyEvent::Base;
1228		1609
1229	# default implementations for many methods	1610	# default implementations for many methods
1230		1611
1231	sub _time {	1612	sub time {
		1613	eval q{ # poor man's autoloading {}
1232	# probe for availability of Time::HiRes	1614	# probe for availability of Time::HiRes
1233	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1615	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1234	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1616	*time = sub { Time::HiRes::time () };
1235	*_time = \&Time::HiRes::time;	1617	*AE::time = \& Time::HiRes::time ;
		1618	*now = \&time;
		1619	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1236	# if (eval "use POSIX (); (POSIX::times())...	1620	# if (eval "use POSIX (); (POSIX::times())...
1237	} else {	1621	} else {
		1622	*time = sub { CORE::time };
		1623	*AE::time = sub (){ CORE::time };
		1624	*now = \&time;
1238	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1625	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
1239	*_time = sub { time }; # epic fail	1626	}
1240	}	1627	};
		1628	die if $@;
1241		1629
1242	&_time	1630	&time
1243	}	1631	}
1244		1632
1245	sub time { _time }	1633	*now = \&time;
1246	sub now { _time }
1247	sub now_update { }	1634	sub now_update { }
1248		1635
		1636	sub _poll {
		1637	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1638	}
		1639
1249	# default implementation for ->condvar	1640	# default implementation for ->condvar
		1641	# in fact, the default should not be overwritten
1250		1642
1251	sub condvar {	1643	sub condvar {
		1644	eval q{ # poor man's autoloading {}
		1645	*condvar = sub {
1252	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1646	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1647	};
		1648
		1649	*AE::cv = sub (;&) {
		1650	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1651	};
		1652	};
		1653	die if $@;
		1654
		1655	&condvar
1253	}	1656	}
1254		1657
1255	# default implementation for ->signal	1658	# default implementation for ->signal
1256		1659
1257	our $HAVE_ASYNC_INTERRUPT;	1660	our $HAVE_ASYNC_INTERRUPT;
		1661
		1662	sub _have_async_interrupt() {
		1663	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1664	&& eval "use Async::Interrupt 1.02 (); 1")
		1665	unless defined $HAVE_ASYNC_INTERRUPT;
		1666
		1667	$HAVE_ASYNC_INTERRUPT
		1668	}
		1669
1258	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1670	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1259	our (%SIG_ASY, %SIG_ASY_W);	1671	our (%SIG_ASY, %SIG_ASY_W);
1260	our ($SIG_COUNT, $SIG_TW);	1672	our ($SIG_COUNT, $SIG_TW);
1261		1673
1262	sub _signal_exec {	1674	# install a dummy wakeup watcher to reduce signal catching latency
1263	$HAVE_ASYNC_INTERRUPT	1675	# used by Impls
1264	? $SIGPIPE_R->drain	1676	sub _sig_add() {
1265	: sysread $SIGPIPE_R, my $dummy, 9;	1677	unless ($SIG_COUNT++) {
		1678	# try to align timer on a full-second boundary, if possible
		1679	my $NOW = AE::now;
1266		1680
1267	while (%SIG_EV) {	1681	$SIG_TW = AE::timer
1268	for (keys %SIG_EV) {	1682	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1269	delete $SIG_EV{$_};	1683	$MAX_SIGNAL_LATENCY,
1270	$_->() for values %{ $SIG_CB{$_} || {} };	1684	sub { } # just for the PERL_ASYNC_CHECK
1271	}	1685	;
1272	}	1686	}
1273	}	1687	}
1274		1688
1275	sub _signal {	1689	sub _sig_del {
1276	my (undef, %arg) = @_;
1277
1278	my $signal = uc $arg{signal}
1279	or Carp::croak "required option 'signal' is missing";
1280
1281	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1282
1283	if ($HAVE_ASYNC_INTERRUPT) {
1284	# async::interrupt
1285
1286	$SIG_ASY{$signal} ||= do {
1287	my $asy = new Async::Interrupt
1288	cb => sub { undef $SIG_EV{$signal} },
1289	signal => $signal,
1290	pipe => [$SIGPIPE_R->filenos],
1291	;
1292	$asy->pipe_autodrain (0);
1293
1294	$asy
1295	};
1296
1297	} else {
1298	# pure perl
1299
1300	$SIG{$signal} ||= sub {
1301	local $!;
1302	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1303	undef $SIG_EV{$signal};
1304	};
1305
1306	# can't do signal processing without introducing races in pure perl,
1307	# so limit the signal latency.
1308	++$SIG_COUNT;
1309	$SIG_TW ||= AnyEvent->timer (
1310	after => $MAX_SIGNAL_LATENCY,
1311	interval => $MAX_SIGNAL_LATENCY,
1312	cb => sub { }, # just for the PERL_ASYNC_CHECK
1313	);
1314	}
1315
1316	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1317	}
1318
1319	sub signal {
1320	# probe for availability of Async::Interrupt
1321	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1322	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1323
1324	$HAVE_ASYNC_INTERRUPT = 1;
1325	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1326	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1327
1328	} else {
1329	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1330
1331	require Fcntl;
1332
1333	if (AnyEvent::WIN32) {
1334	require AnyEvent::Util;
1335
1336	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1337	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1338	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1339	} else {
1340	pipe $SIGPIPE_R, $SIGPIPE_W;
1341	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1342	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1343
1344	# not strictly required, as $^F is normally 2, but let's make sure...
1345	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1346	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1347	}
1348
1349	$SIGPIPE_R
1350	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1351
1352	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1353	}
1354
1355	*signal = \&_signal;
1356	&signal
1357	}
1358
1359	sub AnyEvent::Base::signal::DESTROY {
1360	my ($signal, $cb) = @{$_[0]};
1361
1362	undef $SIG_TW	1690	undef $SIG_TW
1363	unless --$SIG_COUNT;	1691	unless --$SIG_COUNT;
		1692	}
1364		1693
		1694	our $_sig_name_init; $_sig_name_init = sub {
		1695	eval q{ # poor man's autoloading {}
		1696	undef $_sig_name_init;
		1697
		1698	if (_have_async_interrupt) {
		1699	*sig2num = \&Async::Interrupt::sig2num;
		1700	*sig2name = \&Async::Interrupt::sig2name;
		1701	} else {
		1702	require Config;
		1703
		1704	my %signame2num;
		1705	@signame2num{ split ' ', $Config::Config{sig_name} }
		1706	= split ' ', $Config::Config{sig_num};
		1707
		1708	my @signum2name;
		1709	@signum2name[values %signame2num] = keys %signame2num;
		1710
		1711	*sig2num = sub($) {
		1712	$_[0] > 0 ? shift : $signame2num{+shift}
		1713	};
		1714	*sig2name = sub ($) {
		1715	$_[0] > 0 ? $signum2name[+shift] : shift
		1716	};
		1717	}
		1718	};
		1719	die if $@;
		1720	};
		1721
		1722	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1723	sub sig2name($) { &$_sig_name_init; &sig2name }
		1724
		1725	sub signal {
		1726	eval q{ # poor man's autoloading {}
		1727	# probe for availability of Async::Interrupt
		1728	if (_have_async_interrupt) {
		1729	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
		1730
		1731	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1732	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1733
		1734	} else {
		1735	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
		1736
		1737	if (AnyEvent::WIN32) {
		1738	require AnyEvent::Util;
		1739
		1740	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1741	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1742	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1743	} else {
		1744	pipe $SIGPIPE_R, $SIGPIPE_W;
		1745	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1746	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1747
		1748	# not strictly required, as $^F is normally 2, but let's make sure...
		1749	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1750	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1751	}
		1752
		1753	$SIGPIPE_R
		1754	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1755
		1756	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1757	}
		1758
		1759	*signal = $HAVE_ASYNC_INTERRUPT
		1760	? sub {
		1761	my (undef, %arg) = @_;
		1762
		1763	# async::interrupt
		1764	my $signal = sig2num $arg{signal};
		1765	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1766
		1767	$SIG_ASY{$signal} ||= new Async::Interrupt
		1768	cb => sub { undef $SIG_EV{$signal} },
		1769	signal => $signal,
		1770	pipe => [$SIGPIPE_R->filenos],
		1771	pipe_autodrain => 0,
		1772	;
		1773
		1774	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1775	}
		1776	: sub {
		1777	my (undef, %arg) = @_;
		1778
		1779	# pure perl
		1780	my $signal = sig2name $arg{signal};
		1781	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1782
		1783	$SIG{$signal} ||= sub {
		1784	local $!;
		1785	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1786	undef $SIG_EV{$signal};
		1787	};
		1788
		1789	# can't do signal processing without introducing races in pure perl,
		1790	# so limit the signal latency.
		1791	_sig_add;
		1792
		1793	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1794	}
		1795	;
		1796
		1797	*AnyEvent::Base::signal::DESTROY = sub {
		1798	my ($signal, $cb) = @{$_[0]};
		1799
		1800	_sig_del;
		1801
1365	delete $SIG_CB{$signal}{$cb};	1802	delete $SIG_CB{$signal}{$cb};
1366		1803
1367	$HAVE_ASYNC_INTERRUPT	1804	$HAVE_ASYNC_INTERRUPT
1368	? delete $SIG_ASY{$signal}	1805	? delete $SIG_ASY{$signal}
1369	: # delete doesn't work with older perls - they then	1806	: # delete doesn't work with older perls - they then
1370	# print weird messages, or just unconditionally exit	1807	# print weird messages, or just unconditionally exit
1371	# instead of getting the default action.	1808	# instead of getting the default action.
1372	undef $SIG{$signal}	1809	undef $SIG{$signal}
1373	unless keys %{ $SIG_CB{$signal} };	1810	unless keys %{ $SIG_CB{$signal} };
		1811	};
		1812
		1813	*_signal_exec = sub {
		1814	$HAVE_ASYNC_INTERRUPT
		1815	? $SIGPIPE_R->drain
		1816	: sysread $SIGPIPE_R, (my $dummy), 9;
		1817
		1818	while (%SIG_EV) {
		1819	for (keys %SIG_EV) {
		1820	delete $SIG_EV{$_};
		1821	&$_ for values %{ $SIG_CB{$_} || {} };
		1822	}
		1823	}
		1824	};
		1825	};
		1826	die if $@;
		1827
		1828	&signal
1374	}	1829	}
1375		1830
1376	# default implementation for ->child	1831	# default implementation for ->child
1377		1832
1378	our %PID_CB;	1833	our %PID_CB;
1379	our $CHLD_W;	1834	our $CHLD_W;
1380	our $CHLD_DELAY_W;	1835	our $CHLD_DELAY_W;
1381	our $WNOHANG;
1382		1836
1383	sub _sigchld {	1837	# used by many Impl's
1384	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1838	sub _emit_childstatus($$) {
1385	$_->($pid, $?)	1839	my (undef, $rpid, $rstatus) = @_;
		1840
		1841	$_->($rpid, $rstatus)
1386	for values %{ $PID_CB{$pid} || {} },	1842	for values %{ $PID_CB{$rpid} || {} },
1387	values %{ $PID_CB{0} || {} };	1843	values %{ $PID_CB{0} || {} };
1388	}
1389	}	1844	}
1390		1845
1391	sub child {	1846	sub child {
		1847	eval q{ # poor man's autoloading {}
		1848	*_sigchld = sub {
		1849	my $pid;
		1850
		1851	AnyEvent->_emit_childstatus ($pid, $?)
		1852	while ($pid = waitpid -1, WNOHANG) > 0;
		1853	};
		1854
		1855	*child = sub {
1392	my (undef, %arg) = @_;	1856	my (undef, %arg) = @_;
1393		1857
1394	defined (my $pid = $arg{pid} + 0)	1858	my $pid = $arg{pid};
1395	or Carp::croak "required option 'pid' is missing";	1859	my $cb = $arg{cb};
1396		1860
1397	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1861	$PID_CB{$pid}{$cb+0} = $cb;
1398		1862
1399	# WNOHANG is almost cetrainly 1 everywhere
1400	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1401	? 1
1402	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1403
1404	unless ($CHLD_W) {	1863	unless ($CHLD_W) {
1405	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1864	$CHLD_W = AE::signal CHLD => \&_sigchld;
1406	# child could be a zombie already, so make at least one round	1865	# child could be a zombie already, so make at least one round
1407	&_sigchld;	1866	&_sigchld;
1408	}	1867	}
1409		1868
1410	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1869	bless [$pid, $cb+0], "AnyEvent::Base::child"
1411	}	1870	};
1412		1871
1413	sub AnyEvent::Base::child::DESTROY {	1872	*AnyEvent::Base::child::DESTROY = sub {
1414	my ($pid, $cb) = @{$_[0]};	1873	my ($pid, $icb) = @{$_[0]};
1415		1874
1416	delete $PID_CB{$pid}{$cb};	1875	delete $PID_CB{$pid}{$icb};
1417	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1876	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1418		1877
1419	undef $CHLD_W unless keys %PID_CB;	1878	undef $CHLD_W unless keys %PID_CB;
		1879	};
		1880	};
		1881	die if $@;
		1882
		1883	&child
1420	}	1884	}
1421		1885
1422	# idle emulation is done by simply using a timer, regardless	1886	# idle emulation is done by simply using a timer, regardless
1423	# of whether the process is idle or not, and not letting	1887	# of whether the process is idle or not, and not letting
1424	# the callback use more than 50% of the time.	1888	# the callback use more than 50% of the time.
1425	sub idle {	1889	sub idle {
		1890	eval q{ # poor man's autoloading {}
		1891	*idle = sub {
1426	my (undef, %arg) = @_;	1892	my (undef, %arg) = @_;
1427		1893
1428	my ($cb, $w, $rcb) = $arg{cb};	1894	my ($cb, $w, $rcb) = $arg{cb};
1429		1895
1430	$rcb = sub {	1896	$rcb = sub {
1431	if ($cb) {	1897	if ($cb) {
1432	$w = _time;	1898	$w = AE::time;
1433	&$cb;	1899	&$cb;
1434	$w = _time - $w;	1900	$w = AE::time - $w;
1435		1901
1436	# never use more then 50% of the time for the idle watcher,	1902	# never use more then 50% of the time for the idle watcher,
1437	# within some limits	1903	# within some limits
1438	$w = 0.0001 if $w < 0.0001;	1904	$w = 0.0001 if $w < 0.0001;
1439	$w = 5 if $w > 5;	1905	$w = 5 if $w > 5;
1440		1906
1441	$w = AnyEvent->timer (after => $w, cb => $rcb);	1907	$w = AE::timer $w, 0, $rcb;
1442	} else {	1908	} else {
1443	# clean up...	1909	# clean up...
1444	undef $w;	1910	undef $w;
1445	undef $rcb;	1911	undef $rcb;
		1912	}
		1913	};
		1914
		1915	$w = AE::timer 0.05, 0, $rcb;
		1916
		1917	bless \\$cb, "AnyEvent::Base::idle"
1446	}	1918	};
		1919
		1920	*AnyEvent::Base::idle::DESTROY = sub {
		1921	undef $${$_[0]};
		1922	};
1447	};	1923	};
		1924	die if $@;
1448		1925
1449	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1926	&idle
1450
1451	bless \\$cb, "AnyEvent::Base::idle"
1452	}
1453
1454	sub AnyEvent::Base::idle::DESTROY {
1455	undef $${$_[0]};
1456	}	1927	}
1457		1928
1458	package AnyEvent::CondVar;	1929	package AnyEvent::CondVar;
1459		1930
1460	our @ISA = AnyEvent::CondVar::Base::;	1931	our @ISA = AnyEvent::CondVar::Base::;
		1932
		1933	# only to be used for subclassing
		1934	sub new {
		1935	my $class = shift;
		1936	bless AnyEvent->condvar (@_), $class
		1937	}
1461		1938
1462	package AnyEvent::CondVar::Base;	1939	package AnyEvent::CondVar::Base;
1463		1940
1464	#use overload	1941	#use overload
1465	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1942	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1475		1952
1476	sub _send {	1953	sub _send {
1477	# nop	1954	# nop
1478	}	1955	}
1479		1956
		1957	sub _wait {
		1958	AnyEvent->_poll until $_[0]{_ae_sent};
		1959	}
		1960
1480	sub send {	1961	sub send {
1481	my $cv = shift;	1962	my $cv = shift;
1482	$cv->{_ae_sent} = [@_];	1963	$cv->{_ae_sent} = [@_];
1483	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1964	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1484	$cv->_send;	1965	$cv->_send;
…		…
1491		1972
1492	sub ready {	1973	sub ready {
1493	$_[0]{_ae_sent}	1974	$_[0]{_ae_sent}
1494	}	1975	}
1495		1976
1496	sub _wait {
1497	$WAITING
1498	and !$_[0]{_ae_sent}
1499	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1500
1501	local $WAITING = 1;
1502	AnyEvent->one_event while !$_[0]{_ae_sent};
1503	}
1504
1505	sub recv {	1977	sub recv {
		1978	unless ($_[0]{_ae_sent}) {
		1979	$WAITING
		1980	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1981
		1982	local $WAITING = 1;
1506	$_[0]->_wait;	1983	$_[0]->_wait;
		1984	}
1507		1985
1508	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1986	$_[0]{_ae_croak}
1509	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1987	and Carp::croak $_[0]{_ae_croak};
		1988
		1989	wantarray
		1990	? @{ $_[0]{_ae_sent} }
		1991	: $_[0]{_ae_sent}[0]
1510	}	1992	}
1511		1993
1512	sub cb {	1994	sub cb {
1513	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1995	my $cv = shift;
		1996
		1997	@_
		1998	and $cv->{_ae_cb} = shift
		1999	and $cv->{_ae_sent}
		2000	and (delete $cv->{_ae_cb})->($cv);
		2001
1514	$_[0]{_ae_cb}	2002	$cv->{_ae_cb}
1515	}	2003	}
1516		2004
1517	sub begin {	2005	sub begin {
1518	++$_[0]{_ae_counter};	2006	++$_[0]{_ae_counter};
1519	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	2007	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1524	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2012	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1525	}	2013	}
1526		2014
1527	# undocumented/compatibility with pre-3.4	2015	# undocumented/compatibility with pre-3.4
1528	*broadcast = \&send;	2016	*broadcast = \&send;
1529	*wait = \&_wait;	2017	*wait = \&recv;
1530		2018
1531	=head1 ERROR AND EXCEPTION HANDLING	2019	=head1 ERROR AND EXCEPTION HANDLING
1532		2020
1533	In general, AnyEvent does not do any error handling - it relies on the	2021	In general, AnyEvent does not do any error handling - it relies on the
1534	caller to do that if required. The L<AnyEvent::Strict> module (see also	2022	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1546	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2034	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1547	so on.	2035	so on.
1548		2036
1549	=head1 ENVIRONMENT VARIABLES	2037	=head1 ENVIRONMENT VARIABLES
1550		2038
1551	The following environment variables are used by this module or its	2039	AnyEvent supports a number of environment variables that tune the
1552	submodules.	2040	runtime behaviour. They are usually evaluated when AnyEvent is
		2041	loaded, initialised, or a submodule that uses them is loaded. Many of
		2042	them also cause AnyEvent to load additional modules - for example,
		2043	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2044	loaded.
1553		2045
1554	Note that AnyEvent will remove I<all> environment variables starting with	2046	All the environment variables documented here start with
1555	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2047	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1556	enabled.	2048	namespace. Other modules are encouraged (but by no means required) to use
		2049	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2050	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2051	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2052	variables starting with C<AE_>, see below).
		2053
		2054	All variables can also be set via the C<AE_> prefix, that is, instead
		2055	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2056	case there is a clash btween anyevent and another program that uses
		2057	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2058	variable to the empty string, as those variables take precedence.
		2059
		2060	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2061	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2062	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2063	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2064	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2065	is set).
		2066
		2067	The exact algorithm is currently:
		2068
		2069	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2070	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2071	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2072
		2073	This ensures that child processes will not see the C<AE_> variables.
		2074
		2075	The following environment variables are currently known to AnyEvent:
1557		2076
1558	=over 4	2077	=over 4
1559		2078
1560	=item C<PERL_ANYEVENT_VERBOSE>	2079	=item C<PERL_ANYEVENT_VERBOSE>
1561		2080
1562	By default, AnyEvent will be completely silent except in fatal	2081	By default, AnyEvent will only log messages with loglevel C<3>
1563	conditions. You can set this environment variable to make AnyEvent more	2082	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2083	environment variable to a numerical loglevel to make AnyEvent more (or
1564	talkative.	2084	less) talkative.
1565		2085
		2086	If you want to do more than just set the global logging level
		2087	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2088	complex specifications.
		2089
		2090	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2091	the default logging settings.
		2092
1566	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2093	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
1567	conditions, such as not being able to load the event model specified by	2094	unexpected conditions, such as not being able to load the event model
1568	C<PERL_ANYEVENT_MODEL>.	2095	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2096	exception - this is the minimum recommended level.
1569		2097
1570	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2098	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1571	model it chooses.	2099	chooses.
1572		2100
1573	When set to C<8> or higher, then AnyEvent will report extra information on	2101	When set to C<8> or higher (debug), then AnyEvent will report extra information on
1574	which optional modules it loads and how it implements certain features.	2102	which optional modules it loads and how it implements certain features.
		2103
		2104	=item C<PERL_ANYEVENT_LOG>
		2105
		2106	Accepts rather complex logging specifications. For example, you could log
		2107	all C<debug> messages of some module to stderr, warnings and above to
		2108	stderr, and errors and above to syslog, with:
		2109
		2110	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2111
		2112	For the rather extensive details, see L<AnyEvent::Log>.
		2113
		2114	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2115	so will take effect even before AnyEvent has initialised itself.
		2116
		2117	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2118	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2119	using the latter saves a few hundred kB of memory until the first message
		2120	is being logged.
1575		2121
1576	=item C<PERL_ANYEVENT_STRICT>	2122	=item C<PERL_ANYEVENT_STRICT>
1577		2123
1578	AnyEvent does not do much argument checking by default, as thorough	2124	AnyEvent does not do much argument checking by default, as thorough
1579	argument checking is very costly. Setting this variable to a true value	2125	argument checking is very costly. Setting this variable to a true value
…		…
1581	check the arguments passed to most method calls. If it finds any problems,	2127	check the arguments passed to most method calls. If it finds any problems,
1582	it will croak.	2128	it will croak.
1583		2129
1584	In other words, enables "strict" mode.	2130	In other words, enables "strict" mode.
1585		2131
1586	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	2132	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1587	>>, it is definitely recommended to keep it off in production. Keeping	2133	>>, it is definitely recommended to keep it off in production. Keeping
1588	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	2134	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1589	can be very useful, however.	2135	can be very useful, however.
1590		2136
		2137	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2138
		2139	If this env variable is nonempty, then its contents will be interpreted by
		2140	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2141	replacing every occurance of C<$$> by the process pid). The shell object
		2142	is saved in C<$AnyEvent::Debug::SHELL>.
		2143
		2144	This happens when the first watcher is created.
		2145
		2146	For example, to bind a debug shell on a unix domain socket in
		2147	F<< /tmp/debug<pid>.sock >>, you could use this:
		2148
		2149	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2150	# connect with e.g.: socat readline /tmp/debug123.sock
		2151
		2152	Or to bind to tcp port 4545 on localhost:
		2153
		2154	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2155	# connect with e.g.: telnet localhost 4545
		2156
		2157	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2158	multiuser systems.
		2159
		2160	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2161
		2162	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2163	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2164
1591	=item C<PERL_ANYEVENT_MODEL>	2165	=item C<PERL_ANYEVENT_MODEL>
1592		2166
1593	This can be used to specify the event model to be used by AnyEvent, before	2167	This can be used to specify the event model to be used by AnyEvent, before
1594	auto detection and -probing kicks in. It must be a string consisting	2168	auto detection and -probing kicks in.
1595	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2169
		2170	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2171	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1596	and the resulting module name is loaded and if the load was successful,	2172	resulting module name is loaded and - if the load was successful - used as
1597	used as event model. If it fails to load AnyEvent will proceed with	2173	event model backend. If it fails to load then AnyEvent will proceed with
1598	auto detection and -probing.	2174	auto detection and -probing.
1599		2175
1600	This functionality might change in future versions.	2176	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2177	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2178	the end of a string designates a module name and quotes it appropriately).
1601		2179
1602	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2180	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1603	could start your program like this:	2181	could start your program like this:
1604		2182
1605	PERL_ANYEVENT_MODEL=Perl perl ...	2183	PERL_ANYEVENT_MODEL=Perl perl ...
1606		2184
1607	=item C<PERL_ANYEVENT_PROTOCOLS>	2185	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1623	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2201	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1624	- only support IPv4, never try to resolve or contact IPv6	2202	- only support IPv4, never try to resolve or contact IPv6
1625	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2203	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1626	IPv6, but prefer IPv6 over IPv4.	2204	IPv6, but prefer IPv6 over IPv4.
1627		2205
		2206	=item C<PERL_ANYEVENT_HOSTS>
		2207
		2208	This variable, if specified, overrides the F</etc/hosts> file used by
		2209	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2210	from that file instead.
		2211
1628	=item C<PERL_ANYEVENT_EDNS0>	2212	=item C<PERL_ANYEVENT_EDNS0>
1629		2213
1630	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2214	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1631	for DNS. This extension is generally useful to reduce DNS traffic, but	2215	DNS. This extension is generally useful to reduce DNS traffic, especially
1632	some (broken) firewalls drop such DNS packets, which is why it is off by	2216	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1633	default.	2217	packets, which is why it is off by default.
1634		2218
1635	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2219	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1636	EDNS0 in its DNS requests.	2220	EDNS0 in its DNS requests.
1637		2221
1638	=item C<PERL_ANYEVENT_MAX_FORKS>	2222	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1644		2228
1645	The default value for the C<max_outstanding> parameter for the default DNS	2229	The default value for the C<max_outstanding> parameter for the default DNS
1646	resolver - this is the maximum number of parallel DNS requests that are	2230	resolver - this is the maximum number of parallel DNS requests that are
1647	sent to the DNS server.	2231	sent to the DNS server.
1648		2232
		2233	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2234
		2235	Perl has inherently racy signal handling (you can basically choose between
		2236	losing signals and memory corruption) - pure perl event loops (including
		2237	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2238	have to poll regularly to avoid losing signals.
		2239
		2240	Some event loops are racy, but don't poll regularly, and some event loops
		2241	are written in C but are still racy. For those event loops, AnyEvent
		2242	installs a timer that regularly wakes up the event loop.
		2243
		2244	By default, the interval for this timer is C<10> seconds, but you can
		2245	override this delay with this environment variable (or by setting
		2246	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2247	watchers).
		2248
		2249	Lower values increase CPU (and energy) usage, higher values can introduce
		2250	long delays when reaping children or waiting for signals.
		2251
		2252	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2253	polling (with most event loops).
		2254
1649	=item C<PERL_ANYEVENT_RESOLV_CONF>	2255	=item C<PERL_ANYEVENT_RESOLV_CONF>
1650		2256
1651	The file to use instead of F</etc/resolv.conf> (or OS-specific	2257	The absolute path to a F<resolv.conf>-style file to use instead of
1652	configuration) in the default resolver. When set to the empty string, no	2258	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1653	default config will be used.	2259	resolver, or the empty string to select the default configuration.
1654		2260
1655	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2261	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1656		2262
1657	When neither C<ca_file> nor C<ca_path> was specified during	2263	When neither C<ca_file> nor C<ca_path> was specified during
1658	L<AnyEvent::TLS> context creation, and either of these environment	2264	L<AnyEvent::TLS> context creation, and either of these environment
1659	variables exist, they will be used to specify CA certificate locations	2265	variables are nonempty, they will be used to specify CA certificate
1660	instead of a system-dependent default.	2266	locations instead of a system-dependent default.
1661		2267
1662	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>	2268	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1663		2269
1664	When these are set to C<1>, then the respective modules are not	2270	When these are set to C<1>, then the respective modules are not
1665	loaded. Mostly good for testing AnyEvent itself.	2271	loaded. Mostly good for testing AnyEvent itself.
…		…
1728	warn "read: $input\n"; # output what has been read	2334	warn "read: $input\n"; # output what has been read
1729	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2335	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1730	},	2336	},
1731	);	2337	);
1732		2338
1733	my $time_watcher; # can only be used once
1734
1735	sub new_timer {
1736	$timer = AnyEvent->timer (after => 1, cb => sub {	2339	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1737	warn "timeout\n"; # print 'timeout' about every second	2340	warn "timeout\n"; # print 'timeout' at most every second
1738	&new_timer; # and restart the time
1739	});	2341	});
1740	}
1741
1742	new_timer; # create first timer
1743		2342
1744	$cv->recv; # wait until user enters /^q/i	2343	$cv->recv; # wait until user enters /^q/i
1745		2344
1746	=head1 REAL-WORLD EXAMPLE	2345	=head1 REAL-WORLD EXAMPLE
1747		2346
…		…
1820		2419
1821	The actual code goes further and collects all errors (C<die>s, exceptions)	2420	The actual code goes further and collects all errors (C<die>s, exceptions)
1822	that occurred during request processing. The C<result> method detects	2421	that occurred during request processing. The C<result> method detects
1823	whether an exception as thrown (it is stored inside the $txn object)	2422	whether an exception as thrown (it is stored inside the $txn object)
1824	and just throws the exception, which means connection errors and other	2423	and just throws the exception, which means connection errors and other
1825	problems get reported tot he code that tries to use the result, not in a	2424	problems get reported to the code that tries to use the result, not in a
1826	random callback.	2425	random callback.
1827		2426
1828	All of this enables the following usage styles:	2427	All of this enables the following usage styles:
1829		2428
1830	1. Blocking:	2429	1. Blocking:
…		…
1878	through AnyEvent. The benchmark creates a lot of timers (with a zero	2477	through AnyEvent. The benchmark creates a lot of timers (with a zero
1879	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2478	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1880	which it is), lets them fire exactly once and destroys them again.	2479	which it is), lets them fire exactly once and destroys them again.
1881		2480
1882	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2481	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1883	distribution.	2482	distribution. It uses the L<AE> interface, which makes a real difference
		2483	for the EV and Perl backends only.
1884		2484
1885	=head3 Explanation of the columns	2485	=head3 Explanation of the columns
1886		2486
1887	I<watcher> is the number of event watchers created/destroyed. Since	2487	I<watcher> is the number of event watchers created/destroyed. Since
1888	different event models feature vastly different performances, each event	2488	different event models feature vastly different performances, each event
…		…
1909	watcher.	2509	watcher.
1910		2510
1911	=head3 Results	2511	=head3 Results
1912		2512
1913	name watchers bytes create invoke destroy comment	2513	name watchers bytes create invoke destroy comment
1914	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2514	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1915	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2515	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1916	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2516	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1917	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2517	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1918	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2518	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1919	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2519	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1920	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2520	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1921	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2521	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1922	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2522	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1923	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2523	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1924	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2524	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1925	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2525	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1926		2526
1927	=head3 Discussion	2527	=head3 Discussion
1928		2528
1929	The benchmark does I<not> measure scalability of the event loop very	2529	The benchmark does I<not> measure scalability of the event loop very
1930	well. For example, a select-based event loop (such as the pure perl one)	2530	well. For example, a select-based event loop (such as the pure perl one)
…		…
1942	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2542	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1943	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2543	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1944	cycles with POE.	2544	cycles with POE.
1945		2545
1946	C<EV> is the sole leader regarding speed and memory use, which are both	2546	C<EV> is the sole leader regarding speed and memory use, which are both
1947	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2547	maximal/minimal, respectively. When using the L<AE> API there is zero
		2548	overhead (when going through the AnyEvent API create is about 5-6 times
		2549	slower, with other times being equal, so still uses far less memory than
1948	far less memory than any other event loop and is still faster than Event	2550	any other event loop and is still faster than Event natively).
1949	natively.
1950		2551
1951	The pure perl implementation is hit in a few sweet spots (both the	2552	The pure perl implementation is hit in a few sweet spots (both the
1952	constant timeout and the use of a single fd hit optimisations in the perl	2553	constant timeout and the use of a single fd hit optimisations in the perl
1953	interpreter and the backend itself). Nevertheless this shows that it	2554	interpreter and the backend itself). Nevertheless this shows that it
1954	adds very little overhead in itself. Like any select-based backend its	2555	adds very little overhead in itself. Like any select-based backend its
…		…
2002	(even when used without AnyEvent), but most event loops have acceptable	2603	(even when used without AnyEvent), but most event loops have acceptable
2003	performance with or without AnyEvent.	2604	performance with or without AnyEvent.
2004		2605
2005	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2606	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2006	the actual event loop, only with extremely fast event loops such as EV	2607	the actual event loop, only with extremely fast event loops such as EV
2007	adds AnyEvent significant overhead.	2608	does AnyEvent add significant overhead.
2008		2609
2009	=item * You should avoid POE like the plague if you want performance or	2610	=item * You should avoid POE like the plague if you want performance or
2010	reasonable memory usage.	2611	reasonable memory usage.
2011		2612
2012	=back	2613	=back
…		…
2028	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2629	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2029	(1%) are active. This mirrors the activity of large servers with many	2630	(1%) are active. This mirrors the activity of large servers with many
2030	connections, most of which are idle at any one point in time.	2631	connections, most of which are idle at any one point in time.
2031		2632
2032	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2633	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2033	distribution.	2634	distribution. It uses the L<AE> interface, which makes a real difference
		2635	for the EV and Perl backends only.
2034		2636
2035	=head3 Explanation of the columns	2637	=head3 Explanation of the columns
2036		2638
2037	I<sockets> is the number of sockets, and twice the number of "servers" (as	2639	I<sockets> is the number of sockets, and twice the number of "servers" (as
2038	each server has a read and write socket end).	2640	each server has a read and write socket end).
…		…
2046	a new one that moves the timeout into the future.	2648	a new one that moves the timeout into the future.
2047		2649
2048	=head3 Results	2650	=head3 Results
2049		2651
2050	name sockets create request	2652	name sockets create request
2051	EV 20000 69.01 11.16	2653	EV 20000 62.66 7.99
2052	Perl 20000 73.32 35.87	2654	Perl 20000 68.32 32.64
2053	IOAsync 20000 157.00 98.14 epoll	2655	IOAsync 20000 174.06 101.15 epoll
2054	IOAsync 20000 159.31 616.06 poll	2656	IOAsync 20000 174.67 610.84 poll
2055	Event 20000 212.62 257.32	2657	Event 20000 202.69 242.91
2056	Glib 20000 651.16 1896.30	2658	Glib 20000 557.01 1689.52
2057	POE 20000 349.67 12317.24 uses POE::Loop::Event	2659	POE 20000 341.54 12086.32 uses POE::Loop::Event
2058		2660
2059	=head3 Discussion	2661	=head3 Discussion
2060		2662
2061	This benchmark I<does> measure scalability and overall performance of the	2663	This benchmark I<does> measure scalability and overall performance of the
2062	particular event loop.	2664	particular event loop.
…		…
2188	As you can see, the AnyEvent + EV combination even beats the	2790	As you can see, the AnyEvent + EV combination even beats the
2189	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2791	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2190	backend easily beats IO::Lambda and POE.	2792	backend easily beats IO::Lambda and POE.
2191		2793
2192	And even the 100% non-blocking version written using the high-level (and	2794	And even the 100% non-blocking version written using the high-level (and
2193	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2795	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2194	large margin, even though it does all of DNS, tcp-connect and socket I/O	2796	higher level ("unoptimised") abstractions by a large margin, even though
2195	in a non-blocking way.	2797	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2196		2798
2197	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2799	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2198	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2800	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2199	part of the IO::lambda distribution and were used without any changes.	2801	part of the IO::Lambda distribution and were used without any changes.
2200		2802
2201		2803
2202	=head1 SIGNALS	2804	=head1 SIGNALS
2203		2805
2204	AnyEvent currently installs handlers for these signals:	2806	AnyEvent currently installs handlers for these signals:
…		…
2241	unless defined $SIG{PIPE};	2843	unless defined $SIG{PIPE};
2242		2844
2243	=head1 RECOMMENDED/OPTIONAL MODULES	2845	=head1 RECOMMENDED/OPTIONAL MODULES
2244		2846
2245	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2847	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2246	it's built-in modules) are required to use it.	2848	its built-in modules) are required to use it.
2247		2849
2248	That does not mean that AnyEvent won't take advantage of some additional	2850	That does not mean that AnyEvent won't take advantage of some additional
2249	modules if they are installed.	2851	modules if they are installed.
2250		2852
2251	This section epxlains which additional modules will be used, and how they	2853	This section explains which additional modules will be used, and how they
2252	affect AnyEvent's operetion.	2854	affect AnyEvent's operation.
2253		2855
2254	=over 4	2856	=over 4
2255		2857
2256	=item L<Async::Interrupt>	2858	=item L<Async::Interrupt>
2257		2859
2258	This slightly arcane module is used to implement fast signal handling: To	2860	This slightly arcane module is used to implement fast signal handling: To
2259	my knowledge, there is no way to do completely race-free and quick	2861	my knowledge, there is no way to do completely race-free and quick
2260	signal handling in pure perl. To ensure that signals still get	2862	signal handling in pure perl. To ensure that signals still get
2261	delivered, AnyEvent will start an interval timer to wake up perl (and	2863	delivered, AnyEvent will start an interval timer to wake up perl (and
2262	catch the signals) with soemd elay (default is 10 seconds, look for	2864	catch the signals) with some delay (default is 10 seconds, look for
2263	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2865	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2264		2866
2265	If this module is available, then it will be used to implement signal	2867	If this module is available, then it will be used to implement signal
2266	catching, which means that signals will not be delayed, and the event loop	2868	catching, which means that signals will not be delayed, and the event loop
2267	will not be interrupted regularly, which is more efficient (And good for	2869	will not be interrupted regularly, which is more efficient (and good for
2268	battery life on laptops).	2870	battery life on laptops).
2269		2871
2270	This affects not just the pure-perl event loop, but also other event loops	2872	This affects not just the pure-perl event loop, but also other event loops
2271	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2873	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2874
		2875	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2876	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2877	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2878	does nothing for those backends.
2272		2879
2273	=item L<EV>	2880	=item L<EV>
2274		2881
2275	This module isn't really "optional", as it is simply one of the backend	2882	This module isn't really "optional", as it is simply one of the backend
2276	event loops that AnyEvent can use. However, it is simply the best event	2883	event loops that AnyEvent can use. However, it is simply the best event
…		…
2279	automatic timer adjustments even when no monotonic clock is available,	2886	automatic timer adjustments even when no monotonic clock is available,
2280	can take avdantage of advanced kernel interfaces such as C<epoll> and	2887	can take avdantage of advanced kernel interfaces such as C<epoll> and
2281	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2888	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2282	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2889	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2283		2890
		2891	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2892	then this module will do nothing for you.
		2893
2284	=item L<Guard>	2894	=item L<Guard>
2285		2895
2286	The guard module, when used, will be used to implement	2896	The guard module, when used, will be used to implement
2287	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2897	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2288	lot less memory), but otherwise doesn't affect guard operation much. It is	2898	lot less memory), but otherwise doesn't affect guard operation much. It is
2289	purely used for performance.	2899	purely used for performance.
2290		2900
2291	=item L<JSON> and L<JSON::XS>	2901	=item L<JSON> and L<JSON::XS>
2292		2902
2293	This module is required when you want to read or write JSON data via	2903	One of these modules is required when you want to read or write JSON data
2294	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2904	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2295	advantage of the ulta-high-speed L<JSON::XS> module when it is installed.	2905	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2296
2297	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2298	installed.
2299		2906
2300	=item L<Net::SSLeay>	2907	=item L<Net::SSLeay>
2301		2908
2302	Implementing TLS/SSL in Perl is certainly interesting, but not very	2909	Implementing TLS/SSL in Perl is certainly interesting, but not very
2303	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2910	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2304	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2911	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2305		2912
2306	=item L<Time::HiRes>	2913	=item L<Time::HiRes>
2307		2914
2308	This module is part of perl since release 5.008. It will be used when the	2915	This module is part of perl since release 5.008. It will be used when the
2309	chosen event library does not come with a timing source on it's own. The	2916	chosen event library does not come with a timing source of its own. The
2310	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2917	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2311	try to use a monotonic clock for timing stability.	2918	try to use a monotonic clock for timing stability.
2312		2919
2313	=back	2920	=back
2314		2921
2315		2922
2316	=head1 FORK	2923	=head1 FORK
2317		2924
2318	Most event libraries are not fork-safe. The ones who are usually are	2925	Most event libraries are not fork-safe. The ones who are usually are
2319	because they rely on inefficient but fork-safe C<select> or C<poll>	2926	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2320	calls. Only L<EV> is fully fork-aware.	2927	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2928	are usually badly thought-out hacks that are incompatible with fork in
		2929	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2930	continue event-processing in both parent and child (or both, if you know
		2931	what you are doing).
		2932
		2933	This means that, in general, you cannot fork and do event processing in
		2934	the child if the event library was initialised before the fork (which
		2935	usually happens when the first AnyEvent watcher is created, or the library
		2936	is loaded).
2321		2937
2322	If you have to fork, you must either do so I<before> creating your first	2938	If you have to fork, you must either do so I<before> creating your first
2323	watcher OR you must not use AnyEvent at all in the child OR you must do	2939	watcher OR you must not use AnyEvent at all in the child OR you must do
2324	something completely out of the scope of AnyEvent.	2940	something completely out of the scope of AnyEvent.
		2941
		2942	The problem of doing event processing in the parent I<and> the child
		2943	is much more complicated: even for backends that I<are> fork-aware or
		2944	fork-safe, their behaviour is not usually what you want: fork clones all
		2945	watchers, that means all timers, I/O watchers etc. are active in both
		2946	parent and child, which is almost never what you want. USing C<exec>
		2947	to start worker children from some kind of manage rprocess is usually
		2948	preferred, because it is much easier and cleaner, at the expense of having
		2949	to have another binary.
2325		2950
2326		2951
2327	=head1 SECURITY CONSIDERATIONS	2952	=head1 SECURITY CONSIDERATIONS
2328		2953
2329	AnyEvent can be forced to load any event model via	2954	AnyEvent can be forced to load any event model via
…		…
2359	pronounced).	2984	pronounced).
2360		2985
2361		2986
2362	=head1 SEE ALSO	2987	=head1 SEE ALSO
2363		2988
2364	Utility functions: L<AnyEvent::Util>.	2989	Tutorial/Introduction: L<AnyEvent::Intro>.
2365		2990
2366	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2991	FAQ: L<AnyEvent::FAQ>.
2367	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2992
		2993	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2994	(simply logging).
		2995
		2996	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2997	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2998
		2999	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		3000	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		3001	L<Qt>, L<POE>, L<FLTK>.
2368		3002
2369	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3003	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2370	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3004	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2371	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3005	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2372	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	3006	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3007	L<AnyEvent::Impl::FLTK>.
2373		3008
2374	Non-blocking file handles, sockets, TCP clients and	3009	Non-blocking handles, pipes, stream sockets, TCP clients and
2375	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3010	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2376		3011
2377	Asynchronous DNS: L<AnyEvent::DNS>.	3012	Asynchronous DNS: L<AnyEvent::DNS>.
2378		3013
2379	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3014	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2380	L<Coro::Event>,
2381		3015
2382	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3016	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2383	L<AnyEvent::HTTP>.	3017	L<AnyEvent::HTTP>.
2384		3018
2385		3019
2386	=head1 AUTHOR	3020	=head1 AUTHOR
2387		3021

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