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Revision 1.366 by root, Wed Aug 17 02:02:38 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	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
142	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
177		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331	account.	357	account.
332		358
333	=item AnyEvent->now_update	359	=item AnyEvent->now_update
334		360
335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
336	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
337	AnyEvent->now >>, above).	363	above).
338		364
339	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
340	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does its own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
375	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
376		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
377	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
378		454
379	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
380	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
383		460
384	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	463	callback arguments.
387		464
…		…
403		480
404	This means you cannot create a child watcher as the very first	481	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which case the latency and race
		488	problems mentioned in the description of signal watchers apply.
408		489
409	Example: fork a process and wait for it	490	Example: fork a process and wait for it
410		491
411	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
412		493
…		…
424	# do something else, then wait for process exit	505	# do something else, then wait for process exit
425	$done->recv;	506	$done->recv;
426		507
427	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
428		509
429	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		511
434	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	513	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		514
438	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
441		527
442	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	529	program is otherwise idle:
…		…
459	});	545	});
460	});	546	});
461		547
462	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
463		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
464	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
467		558
468	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
470		561
471	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
473		566
474	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	569	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	570	becomes true, with the condition variable as the first argument (but not
479	the results).	571	the results).
480		572
481	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
482	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
483	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
484	->send >> method).	576	->send >> method).
485		577
486	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
487	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
488	in time where multiple outstanding events have been processed. And yet	580
489	another way to call them is transactions - each condition variable can be	581	=over 4
490	used to represent a transaction, which finishes at some point and delivers	582
491	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
492		601
493	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
495	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
496	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
509		618
510	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
511	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
512	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
513	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
514	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
515		624
516	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
517	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	627	for the send to occur.
519		628
520	Example: wait for a timer.	629	Example: wait for a timer.
521		630
522	# wait till the result is ready	631	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
524		633
525	# do something such as adding a timer	634	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
527	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
530	after => 1,	639	after => 1,
531	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
532	);	641	);
533		642
534	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
535	# calls send	644	# calls ->send
536	$result_ready->recv;	645	$timer_fired->recv;
537		646
538	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	648	variables are also callable directly.
540		649
541	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	652	$done->recv;
544		653
…		…
550		659
551	...	660	...
552		661
553	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
554		663
555	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
556	results are available:	665	results are available:
557		666
558	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
560	});	669	});
…		…
578	immediately from within send.	687	immediately from within send.
579		688
580	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
582		691
583	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		695
592	=item $cv->croak ($error)	696	=item $cv->croak ($error)
593		697
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
596		700
597	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
598	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detection, but has the overwhelming advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event callback with no connection to the actual code causing
		706	the problem.
599		707
600	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
601		709
602	=item $cv->end	710	=item $cv->end
603		711
…		…
605	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
607		715
608	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
610	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
613		722
614	You can think of C<< $cv->send >> giving you an OR condition (one call	723	You can think of C<< $cv->send >> giving you an OR condition (one call
615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		726
…		…
639	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
640	sending.	749	sending.
641		750
642	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
643	there are results to be passwd back, and the number of tasks that are	752	there are results to be passwd back, and the number of tasks that are
644	begung can potentially be zero:	753	begun can potentially be zero:
645		754
646	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
647		756
648	my %result;	757	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
650		759
651	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
652	$cv->begin;	761	$cv->begin;
653	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	763	$result{$host} = ...;
…		…
670	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
671	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
672	doesn't execute once).	781	doesn't execute once).
673		782
674	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
676	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
677	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
678	call C<end>.	787	call C<end>.
679		788
680	=back	789	=back
…		…
687	=over 4	796	=over 4
688		797
689	=item $cv->recv	798	=item $cv->recv
690		799
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	802	normally.
694		803
695	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
696	will return immediately.	805	will return immediately.
697		806
…		…
699	function will call C<croak>.	808	function will call C<croak>.
700		809
701	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
703		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
704	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
707	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
711		827
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
724	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
725	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
726	waits otherwise.	831	waits otherwise.
727		832
728	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
734		839
735	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	841	replaces it before doing so.
737		842
738	The callback will be called when the condition becomes "true", i.e. when	843	The callback will be called when the condition becomes "true", i.e. when
739	C<send> or C<croak> are called, with the only argument being the condition	844	C<send> or C<croak> are called, with the only argument being the
740	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
741	is guaranteed not to block.	846	callback is called immediately when it is set. Calling C<recv> inside
		847	the callback or at any later time is guaranteed not to block.
742		848
743	=back	849	=back
744		850
745	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
746		852
…		…
749	=over 4	855	=over 4
750		856
751	=item Backends that are autoprobed when no other event loop can be found.	857	=item Backends that are autoprobed when no other event loop can be found.
752		858
753	EV is the preferred backend when no other event loop seems to be in	859	EV is the preferred backend when no other event loop seems to be in
754	use. If EV is not installed, then AnyEvent will try Event, and, failing	860	use. If EV is not installed, then AnyEvent will fall back to its own
755	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
756	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
757		863
758	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
759	AnyEvent::Impl::Event based on Event, very stable, few glitches.
760	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
761		866
762	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
763		868
764	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
765	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
766	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
767	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
768	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
769		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
770	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
771	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
772	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
773	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
774		884
775	=item Backends with special needs.	885	=item Backends with special needs.
776		886
777	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
778	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
779	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
780	everything should just work.	890	everything should just work.
781		891
782	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
783		893
784	Support for IO::Async can only be partial, as it is too broken and
785	architecturally limited to even support the AnyEvent API. It also
786	is the only event loop that needs the loop to be set explicitly, so
787	it can only be used by a main program knowing about AnyEvent. See
788	L<AnyEvent::Impl::Async> for the gory details.
789
790	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
791
792	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
793		895
794	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
795		897
796	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
809		911
810	=back	912	=back
811		913
812	=head1 GLOBAL VARIABLES AND FUNCTIONS	914	=head1 GLOBAL VARIABLES AND FUNCTIONS
813		915
		916	These are not normally required to use AnyEvent, but can be useful to
		917	write AnyEvent extension modules.
		918
814	=over 4	919	=over 4
815		920
816	=item $AnyEvent::MODEL	921	=item $AnyEvent::MODEL
817		922
818	Contains C<undef> until the first watcher is being created. Then it	923	Contains C<undef> until the first watcher is being created, before the
		924	backend has been autodetected.
		925
819	contains the event model that is being used, which is the name of the	926	Afterwards it contains the event model that is being used, which is the
820	Perl class implementing the model. This class is usually one of the	927	name of the Perl class implementing the model. This class is usually one
821	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
822	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
		930	will be C<urxvt::anyevent>).
823		931
824	=item AnyEvent::detect	932	=item AnyEvent::detect
825		933
826	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
827	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
828	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
829	runtime.	937	runtime, and not e.g. during initialisation of your module.
		938
		939	The effect of calling this function is as if a watcher had been created
		940	(specifically, actions that happen "when the first watcher is created"
		941	happen when calling detetc as well).
		942
		943	If you need to do some initialisation before AnyEvent watchers are
		944	created, use C<post_detect>.
830		945
831	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
832		947
833	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
834	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
		950
		951	The block will be executed I<after> the actual backend has been detected
		952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		954	other initialisations - see the sources of L<AnyEvent::Strict> or
		955	L<AnyEvent::AIO> to see how this is used.
		956
		957	The most common usage is to create some global watchers, without forcing
		958	event module detection too early, for example, L<AnyEvent::AIO> creates
		959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		960	avoid autodetecting the event module at load time.
835		961
836	If called in scalar or list context, then it creates and returns an object	962	If called in scalar or list context, then it creates and returns an object
837	that automatically removes the callback again when it is destroyed. See	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
838	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$WATCHER>, but do so only do so after the event loop is initialised.
		969
		970	our WATCHER;
		971
		972	my $guard = AnyEvent::post_detect {
		973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		974	};
		975
		976	# the ||= is important in case post_detect immediately runs the block,
		977	# as to not clobber the newly-created watcher. assigning both watcher and
		978	# post_detect guard to the same variable has the advantage of users being
		979	# able to just C<undef $WATCHER> if the watcher causes them grief.
		980
		981	$WATCHER ||= $guard;
839		982
840	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
841		984
842	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
843	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
844	the event loop has been chosen.	987	after the event loop has been chosen.
845		988
846	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
847	if it contains a true value then the event loop has already been detected,	990	if it is defined then the event loop has already been detected, and the
848	and the array will be ignored.	991	array will be ignored.
849		992
850	Best use C<AnyEvent::post_detect { BLOCK }> instead.	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		994	it, as it takes care of these details.
		995
		996	This variable is mainly useful for modules that can do something useful
		997	when AnyEvent is used and thus want to know when it is initialised, but do
		998	not need to even load it by default. This array provides the means to hook
		999	into AnyEvent passively, without loading it.
		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
		1013
		1014	=item AnyEvent::postpone { BLOCK }
		1015
		1016	Arranges for the block to be executed as soon as possible, but not before
		1017	the call itself returns. In practise, the block will be executed just
		1018	before the event loop polls for new events, or shortly afterwards.
		1019
		1020	This function never returns anything (to make the C<return postpone { ...
		1021	}> idiom more useful.
		1022
		1023	To understand the usefulness of this function, consider a function that
		1024	asynchronously does something for you and returns some transaction
		1025	object or guard to let you cancel the operation. For example,
		1026	C<AnyEvent::Socket::tcp_connect>:
		1027
		1028	# start a conenction attempt unless one is active
		1029	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1030	delete $self->{connect_guard};
		1031	...
		1032	};
		1033
		1034	Imagine that this function could instantly call the callback, for
		1035	example, because it detects an obvious error such as a negative port
		1036	number. Invoking the callback before the function returns causes problems
		1037	however: the callback will be called and will try to delete the guard
		1038	object. But since the function hasn't returned yet, there is nothing to
		1039	delete. When the function eventually returns it will assign the guard
		1040	object to C<< $self->{connect_guard} >>, where it will likely never be
		1041	deleted, so the program thinks it is still trying to connect.
		1042
		1043	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1044	callback directly on error:
		1045
		1046	$cb->(undef), return # signal error to callback, BAD!
		1047	if $some_error_condition;
		1048
		1049	It should use C<postpone>:
		1050
		1051	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1052	if $some_error_condition;
		1053
		1054	=item AnyEvent::log $level, $msg[, @args]
		1055
		1056	Log the given C<$msg> at the given C<$level>.
		1057
		1058	Loads AnyEvent::Log on first use and calls C<AnyEvent::Log::log> -
		1059	consequently, look at the L<AnyEvent::Log> documentation for details.
851		1060
852	=back	1061	=back
853		1062
854	=head1 WHAT TO DO IN A MODULE	1063	=head1 WHAT TO DO IN A MODULE
855		1064
…		…
866	because it will stall the whole program, and the whole point of using	1075	because it will stall the whole program, and the whole point of using
867	events is to stay interactive.	1076	events is to stay interactive.
868		1077
869	It is fine, however, to call C<< ->recv >> when the user of your module	1078	It is fine, however, to call C<< ->recv >> when the user of your module
870	requests it (i.e. if you create a http request object ad have a method	1079	requests it (i.e. if you create a http request object ad have a method
871	called C<results> that returns the results, it should call C<< ->recv >>	1080	called C<results> that returns the results, it may call C<< ->recv >>
872	freely, as the user of your module knows what she is doing. always).	1081	freely, as the user of your module knows what she is doing. Always).
873		1082
874	=head1 WHAT TO DO IN THE MAIN PROGRAM	1083	=head1 WHAT TO DO IN THE MAIN PROGRAM
875		1084
876	There will always be a single main program - the only place that should	1085	There will always be a single main program - the only place that should
877	dictate which event model to use.	1086	dictate which event model to use.
878		1087
879	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1088	If the program is not event-based, it need not do anything special, even
880	do anything special (it does not need to be event-based) and let AnyEvent	1089	when it depends on a module that uses an AnyEvent. If the program itself
881	decide which implementation to chose if some module relies on it.	1090	uses AnyEvent, but does not care which event loop is used, all it needs
		1091	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1092	available loop implementation.
882		1093
883	If the main program relies on a specific event model - for example, in	1094	If the main program relies on a specific event model - for example, in
884	Gtk2 programs you have to rely on the Glib module - you should load the	1095	Gtk2 programs you have to rely on the Glib module - you should load the
885	event module before loading AnyEvent or any module that uses it: generally	1096	event module before loading AnyEvent or any module that uses it: generally
886	speaking, you should load it as early as possible. The reason is that	1097	speaking, you should load it as early as possible. The reason is that
887	modules might create watchers when they are loaded, and AnyEvent will	1098	modules might create watchers when they are loaded, and AnyEvent will
888	decide on the event model to use as soon as it creates watchers, and it	1099	decide on the event model to use as soon as it creates watchers, and it
889	might chose the wrong one unless you load the correct one yourself.	1100	might choose the wrong one unless you load the correct one yourself.
890		1101
891	You can chose to use a pure-perl implementation by loading the	1102	You can chose to use a pure-perl implementation by loading the
892	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1103	C<AnyEvent::Loop> module, which gives you similar behaviour
893	everywhere, but letting AnyEvent chose the model is generally better.	1104	everywhere, but letting AnyEvent chose the model is generally better.
894		1105
895	=head2 MAINLOOP EMULATION	1106	=head2 MAINLOOP EMULATION
896		1107
897	Sometimes (often for short test scripts, or even standalone programs who	1108	Sometimes (often for short test scripts, or even standalone programs who
…		…
912	=head1 OTHER MODULES	1123	=head1 OTHER MODULES
913		1124
914	The following is a non-exhaustive list of additional modules that use	1125	The following is a non-exhaustive list of additional modules that use
915	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1126	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
916	modules and other event loops in the same program. Some of the modules	1127	modules and other event loops in the same program. Some of the modules
917	come with AnyEvent, most are available via CPAN.	1128	come as part of AnyEvent, the others are available via CPAN.
918		1129
919	=over 4	1130	=over 4
920		1131
921	=item L<AnyEvent::Util>	1132	=item L<AnyEvent::Util>
922		1133
923	Contains various utility functions that replace often-used but blocking	1134	Contains various utility functions that replace often-used blocking
924	functions such as C<inet_aton> by event-/callback-based versions.	1135	functions such as C<inet_aton> with event/callback-based versions.
925		1136
926	=item L<AnyEvent::Socket>	1137	=item L<AnyEvent::Socket>
927		1138
928	Provides various utility functions for (internet protocol) sockets,	1139	Provides various utility functions for (internet protocol) sockets,
929	addresses and name resolution. Also functions to create non-blocking tcp	1140	addresses and name resolution. Also functions to create non-blocking tcp
…		…
931		1142
932	=item L<AnyEvent::Handle>	1143	=item L<AnyEvent::Handle>
933		1144
934	Provide read and write buffers, manages watchers for reads and writes,	1145	Provide read and write buffers, manages watchers for reads and writes,
935	supports raw and formatted I/O, I/O queued and fully transparent and	1146	supports raw and formatted I/O, I/O queued and fully transparent and
936	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1147	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
937		1148
938	=item L<AnyEvent::DNS>	1149	=item L<AnyEvent::DNS>
939		1150
940	Provides rich asynchronous DNS resolver capabilities.	1151	Provides rich asynchronous DNS resolver capabilities.
941		1152
		1153	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1154
		1155	Implement event-based interfaces to the protocols of the same name (for
		1156	the curious, IGS is the International Go Server and FCP is the Freenet
		1157	Client Protocol).
		1158
		1159	=item L<AnyEvent::Handle::UDP>
		1160
		1161	Here be danger!
		1162
		1163	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1164	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1165	its use of a stream-based API with a protocol that isn't streamable, that
		1166	the only way to improve it is to delete it.
		1167
		1168	It features data corruption (but typically only under load) and general
		1169	confusion. On top, the author is not only clueless about UDP but also
		1170	fact-resistant - some gems of his understanding: "connect doesn't work
		1171	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1172	packets", "I don't need to implement proper error checking as UDP doesn't
		1173	support error checking" and so on - he doesn't even understand what's
		1174	wrong with his module when it is explained to him.
		1175
942	=item L<AnyEvent::HTTP>	1176	=item L<AnyEvent::DBI>
943		1177
944	A simple-to-use HTTP library that is capable of making a lot of concurrent	1178	Executes L<DBI> requests asynchronously in a proxy process for you,
945	HTTP requests.	1179	notifying you in an event-based way when the operation is finished.
		1180
		1181	=item L<AnyEvent::AIO>
		1182
		1183	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1184	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1185	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1186	file I/O, and much more.
946		1187
947	=item L<AnyEvent::HTTPD>	1188	=item L<AnyEvent::HTTPD>
948		1189
949	Provides a simple web application server framework.	1190	A simple embedded webserver.
950		1191
951	=item L<AnyEvent::FastPing>	1192	=item L<AnyEvent::FastPing>
952		1193
953	The fastest ping in the west.	1194	The fastest ping in the west.
954		1195
955	=item L<AnyEvent::DBI>
956
957	Executes L<DBI> requests asynchronously in a proxy process.
958
959	=item L<AnyEvent::AIO>
960
961	Truly asynchronous I/O, should be in the toolbox of every event
962	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
963	together.
964
965	=item L<AnyEvent::BDB>
966
967	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
968	L<BDB> and AnyEvent together.
969
970	=item L<AnyEvent::GPSD>
971
972	A non-blocking interface to gpsd, a daemon delivering GPS information.
973
974	=item L<AnyEvent::IRC>
975
976	AnyEvent based IRC client module family (replacing the older Net::IRC3).
977
978	=item L<AnyEvent::XMPP>
979
980	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
981	Net::XMPP2>.
982
983	=item L<AnyEvent::IGS>
984
985	A non-blocking interface to the Internet Go Server protocol (used by
986	L<App::IGS>).
987
988	=item L<Net::FCP>
989
990	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
991	of AnyEvent.
992
993	=item L<Event::ExecFlow>
994
995	High level API for event-based execution flow control.
996
997	=item L<Coro>	1196	=item L<Coro>
998		1197
999	Has special support for AnyEvent via L<Coro::AnyEvent>.	1198	Has special support for AnyEvent via L<Coro::AnyEvent>.
1000		1199
1001	=back	1200	=back
1002		1201
1003	=cut	1202	=cut
1004		1203
1005	package AnyEvent;	1204	package AnyEvent;
1006		1205
1007	no warnings;	1206	# basically a tuned-down version of common::sense
1008	use strict qw(vars subs);	1207	sub common_sense {
		1208	# from common:.sense 3.4
		1209	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1210	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1211	$^H |= 0x00000600;
		1212	}
1009		1213
		1214	BEGIN { AnyEvent::common_sense }
		1215
1010	use Carp;	1216	use Carp ();
1011		1217
1012	our $VERSION = 4.801;	1218	our $VERSION = '6.01';
1013	our $MODEL;	1219	our $MODEL;
1014		1220
1015	our $AUTOLOAD;
1016	our @ISA;	1221	our @ISA;
1017		1222
1018	our @REGISTRY;	1223	our @REGISTRY;
1019		1224
1020	our $WIN32;	1225	our $VERBOSE;
1021		1226
1022	BEGIN {	1227	BEGIN {
1023	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1228	require "AnyEvent/constants.pl";
		1229
1024	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1230	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1025		1231
1026	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1232	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1027	if ${^TAINT};	1233	if ${^TAINT};
1028	}
1029		1234
1030	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1235	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1236	}
		1237
		1238	our $MAX_SIGNAL_LATENCY = 10;
1031		1239
1032	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1240	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1033		1241
1034	{	1242	{
1035	my $idx;	1243	my $idx;
1036	$PROTOCOL{$_} = ++$idx	1244	$PROTOCOL{$_} = ++$idx
1037	for reverse split /\s*,\s*/,	1245	for reverse split /\s*,\s*/,
1038	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1246	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1039	}	1247	}
1040		1248
		1249	our @post_detect;
		1250
		1251	sub post_detect(&) {
		1252	my ($cb) = @_;
		1253
		1254	push @post_detect, $cb;
		1255
		1256	defined wantarray
		1257	? bless \$cb, "AnyEvent::Util::postdetect"
		1258	: ()
		1259	}
		1260
		1261	sub AnyEvent::Util::postdetect::DESTROY {
		1262	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1263	}
		1264
		1265	our $POSTPONE_W;
		1266	our @POSTPONE;
		1267
		1268	sub _postpone_exec {
		1269	undef $POSTPONE_W;
		1270
		1271	&{ shift @POSTPONE }
		1272	while @POSTPONE;
		1273	}
		1274
		1275	sub postpone(&) {
		1276	push @POSTPONE, shift;
		1277
		1278	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1279
		1280	()
		1281	}
		1282
		1283	sub log($$;@) {
		1284	require AnyEvent::Log;
		1285	# AnyEvent::Log overwrites this function
		1286	goto &log;
		1287	}
		1288
1041	my @models = (	1289	our @models = (
1042	[EV:: => AnyEvent::Impl::EV::],	1290	[EV:: => AnyEvent::Impl::EV:: , 1],
1043	[Event:: => AnyEvent::Impl::Event::],	1291	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1044	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1045	# everything below here will not be autoprobed	1292	# everything below here will not (normally) be autoprobed
1046	# as the pureperl backend should work everywhere	1293	# as the pure perl backend should work everywhere
1047	# and is usually faster	1294	# and is usually faster
		1295	[Event:: => AnyEvent::Impl::Event::, 1],
1048	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1296	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1049	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1297	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1298	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1050	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1299	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		1300	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1051	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1301	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1052	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1053	[Wx:: => AnyEvent::Impl::POE::],	1302	[Wx:: => AnyEvent::Impl::POE::],
1054	[Prima:: => AnyEvent::Impl::POE::],	1303	[Prima:: => AnyEvent::Impl::POE::],
1055	# IO::Async is just too broken - we would need workarounds for its	1304	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1056	# byzantine signal and broken child handling, among others.	1305	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1057	# IO::Async is rather hard to detect, as it doesn't have any	1306	[FLTK:: => AnyEvent::Impl::FLTK2::],
1058	# obvious default class.
1059	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1060	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1061	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1062	);	1307	);
1063		1308
1064	our %method = map +($_ => 1),	1309	our @isa_hook;
		1310
		1311	sub _isa_set {
		1312	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1313
		1314	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1315	for 1 .. $#pkg;
		1316
		1317	grep $_ && $_->[1], @isa_hook
		1318	and AE::_reset ();
		1319	}
		1320
		1321	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1322	sub _isa_hook($$;$) {
		1323	my ($i, $pkg, $reset_ae) = @_;
		1324
		1325	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1326
		1327	_isa_set;
		1328	}
		1329
		1330	# all autoloaded methods reserve the complete glob, not just the method slot.
		1331	# due to bugs in perls method cache implementation.
1065	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1332	our @methods = qw(io timer time now now_update signal child idle condvar);
1066		1333
1067	our @post_detect;
1068
1069	sub post_detect(&) {	1334	sub detect() {
1070	my ($cb) = @_;	1335	return $MODEL if $MODEL; # some programs keep references to detect
1071		1336
1072	if ($MODEL) {	1337	local $!; # for good measure
1073	$cb->();	1338	local $SIG{__DIE__}; # we use eval
1074		1339
1075	1	1340	# free some memory
		1341	*detect = sub () { $MODEL };
		1342	# undef &func doesn't correctly update the method cache. grmbl.
		1343	# so we delete the whole glob. grmbl.
		1344	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1345	# a glob with an active sub. hrm. i hope it works, but perl is
		1346	# usually buggy in this department. sigh.
		1347	delete @{"AnyEvent::"}{@methods};
		1348	undef @methods;
		1349
		1350	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1351	my $model = $1;
		1352	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1353	if (eval "require $model") {
		1354	$MODEL = $model;
		1355	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it."
		1356	if $VERBOSE >= 7;
1076	} else {	1357	} else {
1077	push @post_detect, $cb;	1358	AnyEvent::log warn => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1078		1359	}
1079	defined wantarray
1080	? bless \$cb, "AnyEvent::Util::postdetect"
1081	: ()
1082	}	1360	}
1083	}
1084		1361
1085	sub AnyEvent::Util::postdetect::DESTROY {	1362	# check for already loaded models
1086	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1087	}
1088
1089	sub detect() {
1090	unless ($MODEL) {	1363	unless ($MODEL) {
1091	no strict 'refs';	1364	for (@REGISTRY, @models) {
1092	local $SIG{__DIE__};	1365	my ($package, $model) = @$_;
1093		1366	if (${"$package\::VERSION"} > 0) {
1094	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1095	my $model = "AnyEvent::Impl::$1";
1096	if (eval "require $model") {	1367	if (eval "require $model") {
1097	$MODEL = $model;	1368	$MODEL = $model;
1098	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1369	AnyEvent::log 7 => "autodetected model '$model', using it."
1099	} else {	1370	if $VERBOSE >= 7;
1100	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1371	last;
		1372	}
1101	}	1373	}
1102	}	1374	}
1103		1375
1104	# check for already loaded models
1105	unless ($MODEL) {	1376	unless ($MODEL) {
		1377	# try to autoload a model
1106	for (@REGISTRY, @models) {	1378	for (@REGISTRY, @models) {
1107	my ($package, $model) = @$_;	1379	my ($package, $model, $autoload) = @$_;
		1380	if (
		1381	$autoload
		1382	and eval "require $package"
1108	if (${"$package\::VERSION"} > 0) {	1383	and ${"$package\::VERSION"} > 0
1109	if (eval "require $model") {	1384	and eval "require $model"
		1385	) {
1110	$MODEL = $model;	1386	$MODEL = $model;
1111	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1387	AnyEvent::log 7 => "autoloaded model '$model', using it."
		1388	if $VERBOSE >= 7;
1112	last;	1389	last;
1113	}
1114	}	1390	}
1115	}	1391	}
1116		1392
1117	unless ($MODEL) {
1118	# try to load a model
1119
1120	for (@REGISTRY, @models) {
1121	my ($package, $model) = @$_;
1122	if (eval "require $package"
1123	and ${"$package\::VERSION"} > 0
1124	and eval "require $model") {
1125	$MODEL = $model;
1126	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1127	last;
1128	}
1129	}
1130
1131	$MODEL	1393	$MODEL
1132	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1394	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1133	}
1134	}	1395	}
1135
1136	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1137
1138	unshift @ISA, $MODEL;
1139
1140	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1141
1142	(shift @post_detect)->() while @post_detect;
1143	}	1396	}
1144		1397
		1398	# free memory only needed for probing
		1399	undef @models;
		1400	undef @REGISTRY;
		1401
		1402	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1403
		1404	# now nuke some methods that are overridden by the backend.
		1405	# SUPER usage is not allowed in these.
		1406	for (qw(time signal child idle)) {
		1407	undef &{"AnyEvent::Base::$_"}
		1408	if defined &{"$MODEL\::$_"};
		1409	}
		1410
		1411	_isa_set;
		1412
		1413	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1414	require AnyEvent::Strict;
		1415	}
		1416
		1417	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1418	require AnyEvent::Debug;
		1419	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1420	}
		1421
		1422	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1423	require AnyEvent::Socket;
		1424	require AnyEvent::Debug;
		1425
		1426	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1427	$shell =~ s/\$\$/$$/g;
		1428
		1429	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1430	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1431	}
		1432
		1433	(shift @post_detect)->() while @post_detect;
		1434	undef @post_detect;
		1435
		1436	*post_detect = sub(&) {
		1437	shift->();
		1438
		1439	undef
		1440	};
		1441
1145	$MODEL	1442	$MODEL
1146	}	1443	}
1147		1444
1148	sub AUTOLOAD {	1445	for my $name (@methods) {
1149	(my $func = $AUTOLOAD) =~ s/.*://;	1446	*$name = sub {
1150		1447	detect;
1151	$method{$func}	1448	# we use goto because
1152	or croak "$func: not a valid method for AnyEvent objects";	1449	# a) it makes the thunk more transparent
1153		1450	# b) it allows us to delete the thunk later
1154	detect unless $MODEL;	1451	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1155		1452	};
1156	my $class = shift;
1157	$class->$func (@_);
1158	}	1453	}
1159		1454
1160	# utility function to dup a filehandle. this is used by many backends	1455	# utility function to dup a filehandle. this is used by many backends
1161	# to support binding more than one watcher per filehandle (they usually	1456	# to support binding more than one watcher per filehandle (they usually
1162	# allow only one watcher per fd, so we dup it to get a different one).	1457	# allow only one watcher per fd, so we dup it to get a different one).
1163	sub _dupfh($$;$$) {	1458	sub _dupfh($$;$$) {
1164	my ($poll, $fh, $r, $w) = @_;	1459	my ($poll, $fh, $r, $w) = @_;
1165		1460
1166	# cygwin requires the fh mode to be matching, unix doesn't	1461	# cygwin requires the fh mode to be matching, unix doesn't
1167	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1462	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1168		1463
1169	open my $fh2, "$mode&", $fh	1464	open my $fh2, $mode, $fh
1170	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1465	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1171		1466
1172	# we assume CLOEXEC is already set by perl in all important cases	1467	# we assume CLOEXEC is already set by perl in all important cases
1173		1468
1174	($fh2, $rw)	1469	($fh2, $rw)
1175	}	1470	}
1176		1471
		1472	=head1 SIMPLIFIED AE API
		1473
		1474	Starting with version 5.0, AnyEvent officially supports a second, much
		1475	simpler, API that is designed to reduce the calling, typing and memory
		1476	overhead by using function call syntax and a fixed number of parameters.
		1477
		1478	See the L<AE> manpage for details.
		1479
		1480	=cut
		1481
		1482	package AE;
		1483
		1484	our $VERSION = $AnyEvent::VERSION;
		1485
		1486	sub _reset() {
		1487	eval q{
		1488	# fall back to the main API by default - backends and AnyEvent::Base
		1489	# implementations can overwrite these.
		1490
		1491	sub io($$$) {
		1492	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1493	}
		1494
		1495	sub timer($$$) {
		1496	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1497	}
		1498
		1499	sub signal($$) {
		1500	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1501	}
		1502
		1503	sub child($$) {
		1504	AnyEvent->child (pid => $_[0], cb => $_[1])
		1505	}
		1506
		1507	sub idle($) {
		1508	AnyEvent->idle (cb => $_[0]);
		1509	}
		1510
		1511	sub cv(;&) {
		1512	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1513	}
		1514
		1515	sub now() {
		1516	AnyEvent->now
		1517	}
		1518
		1519	sub now_update() {
		1520	AnyEvent->now_update
		1521	}
		1522
		1523	sub time() {
		1524	AnyEvent->time
		1525	}
		1526
		1527	*postpone = \&AnyEvent::postpone;
		1528	*log = \&AnyEvent::log;
		1529	};
		1530	die if $@;
		1531	}
		1532
		1533	BEGIN { _reset }
		1534
1177	package AnyEvent::Base;	1535	package AnyEvent::Base;
1178		1536
1179	# default implementations for many methods	1537	# default implementations for many methods
1180		1538
1181	BEGIN {	1539	sub time {
		1540	eval q{ # poor man's autoloading {}
		1541	# probe for availability of Time::HiRes
1182	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1542	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1543	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy."
		1544	if $AnyEvent::VERBOSE >= 8;
		1545	*time = sub { Time::HiRes::time () };
1183	*_time = \&Time::HiRes::time;	1546	*AE::time = \& Time::HiRes::time ;
1184	# if (eval "use POSIX (); (POSIX::times())...	1547	# if (eval "use POSIX (); (POSIX::times())...
1185	} else {	1548	} else {
1186	*_time = sub { time }; # epic fail	1549	AnyEvent::log critical => "using built-in time(), WARNING, no sub-second resolution!";
		1550	*time = sub { CORE::time };
		1551	*AE::time = sub (){ CORE::time };
		1552	}
		1553
		1554	*now = \&time;
		1555	};
		1556	die if $@;
		1557
		1558	&time
		1559	}
		1560
		1561	*now = \&time;
		1562	sub now_update { }
		1563
		1564	sub _poll {
		1565	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1566	}
		1567
		1568	# default implementation for ->condvar
		1569	# in fact, the default should not be overwritten
		1570
		1571	sub condvar {
		1572	eval q{ # poor man's autoloading {}
		1573	*condvar = sub {
		1574	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1575	};
		1576
		1577	*AE::cv = sub (;&) {
		1578	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1579	};
		1580	};
		1581	die if $@;
		1582
		1583	&condvar
		1584	}
		1585
		1586	# default implementation for ->signal
		1587
		1588	our $HAVE_ASYNC_INTERRUPT;
		1589
		1590	sub _have_async_interrupt() {
		1591	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1592	&& eval "use Async::Interrupt 1.02 (); 1")
		1593	unless defined $HAVE_ASYNC_INTERRUPT;
		1594
		1595	$HAVE_ASYNC_INTERRUPT
		1596	}
		1597
		1598	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1599	our (%SIG_ASY, %SIG_ASY_W);
		1600	our ($SIG_COUNT, $SIG_TW);
		1601
		1602	# install a dummy wakeup watcher to reduce signal catching latency
		1603	# used by Impls
		1604	sub _sig_add() {
		1605	unless ($SIG_COUNT++) {
		1606	# try to align timer on a full-second boundary, if possible
		1607	my $NOW = AE::now;
		1608
		1609	$SIG_TW = AE::timer
		1610	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1611	$MAX_SIGNAL_LATENCY,
		1612	sub { } # just for the PERL_ASYNC_CHECK
		1613	;
1187	}	1614	}
1188	}	1615	}
1189		1616
1190	sub time { _time }	1617	sub _sig_del {
1191	sub now { _time }	1618	undef $SIG_TW
1192	sub now_update { }	1619	unless --$SIG_COUNT;
1193
1194	# default implementation for ->condvar
1195
1196	sub condvar {
1197	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1198	}	1620	}
1199		1621
1200	# default implementation for ->signal	1622	our $_sig_name_init; $_sig_name_init = sub {
		1623	eval q{ # poor man's autoloading {}
		1624	undef $_sig_name_init;
1201		1625
1202	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1626	if (_have_async_interrupt) {
		1627	*sig2num = \&Async::Interrupt::sig2num;
		1628	*sig2name = \&Async::Interrupt::sig2name;
		1629	} else {
		1630	require Config;
1203		1631
1204	sub _signal_exec {	1632	my %signame2num;
1205	sysread $SIGPIPE_R, my $dummy, 4;	1633	@signame2num{ split ' ', $Config::Config{sig_name} }
		1634	= split ' ', $Config::Config{sig_num};
1206		1635
1207	while (%SIG_EV) {	1636	my @signum2name;
1208	for (keys %SIG_EV) {	1637	@signum2name[values %signame2num] = keys %signame2num;
1209	delete $SIG_EV{$_};	1638
1210	$_->() for values %{ $SIG_CB{$_} || {} };	1639	*sig2num = sub($) {
		1640	$_[0] > 0 ? shift : $signame2num{+shift}
		1641	};
		1642	*sig2name = sub ($) {
		1643	$_[0] > 0 ? $signum2name[+shift] : shift
		1644	};
1211	}	1645	}
1212	}	1646	};
1213	}	1647	die if $@;
		1648	};
		1649
		1650	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1651	sub sig2name($) { &$_sig_name_init; &sig2name }
1214		1652
1215	sub signal {	1653	sub signal {
1216	my (undef, %arg) = @_;	1654	eval q{ # poor man's autoloading {}
		1655	# probe for availability of Async::Interrupt
		1656	if (_have_async_interrupt) {
		1657	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling."
		1658	if $AnyEvent::VERBOSE >= 8;
1217		1659
1218	unless ($SIGPIPE_R) {	1660	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1219	require Fcntl;	1661	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1220		1662
1221	if (AnyEvent::WIN32) {
1222	require AnyEvent::Util;
1223
1224	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1225	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1226	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1227	} else {	1663	} else {
		1664	AnyEvent::log 8 => "using emulated perl signal handling with latency timer."
		1665	if $AnyEvent::VERBOSE >= 8;
		1666
		1667	if (AnyEvent::WIN32) {
		1668	require AnyEvent::Util;
		1669
		1670	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1671	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1672	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1673	} else {
1228	pipe $SIGPIPE_R, $SIGPIPE_W;	1674	pipe $SIGPIPE_R, $SIGPIPE_W;
1229	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1675	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1230	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1676	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1231		1677
1232	# not strictly required, as $^F is normally 2, but let's make sure...	1678	# not strictly required, as $^F is normally 2, but let's make sure...
1233	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1679	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1234	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1680	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1681	}
		1682
		1683	$SIGPIPE_R
		1684	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1685
		1686	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1235	}	1687	}
1236		1688
1237	$SIGPIPE_R	1689	*signal = $HAVE_ASYNC_INTERRUPT
1238	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1690	? sub {
		1691	my (undef, %arg) = @_;
1239		1692
1240	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1693	# async::interrupt
1241	}
1242
1243	my $signal = uc $arg{signal}	1694	my $signal = sig2num $arg{signal};
1244	or Carp::croak "required option 'signal' is missing";
1245
1246	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1695	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1696
		1697	$SIG_ASY{$signal} ||= new Async::Interrupt
		1698	cb => sub { undef $SIG_EV{$signal} },
		1699	signal => $signal,
		1700	pipe => [$SIGPIPE_R->filenos],
		1701	pipe_autodrain => 0,
		1702	;
		1703
		1704	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1705	}
		1706	: sub {
		1707	my (undef, %arg) = @_;
		1708
		1709	# pure perl
		1710	my $signal = sig2name $arg{signal};
		1711	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1712
1247	$SIG{$signal} ||= sub {	1713	$SIG{$signal} ||= sub {
1248	local $!;	1714	local $!;
1249	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1715	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1250	undef $SIG_EV{$signal};	1716	undef $SIG_EV{$signal};
		1717	};
		1718
		1719	# can't do signal processing without introducing races in pure perl,
		1720	# so limit the signal latency.
		1721	_sig_add;
		1722
		1723	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1724	}
		1725	;
		1726
		1727	*AnyEvent::Base::signal::DESTROY = sub {
		1728	my ($signal, $cb) = @{$_[0]};
		1729
		1730	_sig_del;
		1731
		1732	delete $SIG_CB{$signal}{$cb};
		1733
		1734	$HAVE_ASYNC_INTERRUPT
		1735	? delete $SIG_ASY{$signal}
		1736	: # delete doesn't work with older perls - they then
		1737	# print weird messages, or just unconditionally exit
		1738	# instead of getting the default action.
		1739	undef $SIG{$signal}
		1740	unless keys %{ $SIG_CB{$signal} };
		1741	};
		1742
		1743	*_signal_exec = sub {
		1744	$HAVE_ASYNC_INTERRUPT
		1745	? $SIGPIPE_R->drain
		1746	: sysread $SIGPIPE_R, (my $dummy), 9;
		1747
		1748	while (%SIG_EV) {
		1749	for (keys %SIG_EV) {
		1750	delete $SIG_EV{$_};
		1751	&$_ for values %{ $SIG_CB{$_} || {} };
		1752	}
		1753	}
		1754	};
1251	};	1755	};
		1756	die if $@;
1252		1757
1253	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1758	&signal
1254	}
1255
1256	sub AnyEvent::Base::signal::DESTROY {
1257	my ($signal, $cb) = @{$_[0]};
1258
1259	delete $SIG_CB{$signal}{$cb};
1260
1261	# delete doesn't work with older perls - they then
1262	# print weird messages, or just unconditionally exit
1263	# instead of getting the default action.
1264	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1265	}	1759	}
1266		1760
1267	# default implementation for ->child	1761	# default implementation for ->child
1268		1762
1269	our %PID_CB;	1763	our %PID_CB;
1270	our $CHLD_W;	1764	our $CHLD_W;
1271	our $CHLD_DELAY_W;	1765	our $CHLD_DELAY_W;
1272	our $WNOHANG;
1273		1766
1274	sub _sigchld {	1767	# used by many Impl's
1275	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1768	sub _emit_childstatus($$) {
		1769	my (undef, $rpid, $rstatus) = @_;
		1770
		1771	$_->($rpid, $rstatus)
1276	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1772	for values %{ $PID_CB{$rpid} || {} },
1277	(values %{ $PID_CB{0} || {} });	1773	values %{ $PID_CB{0} || {} };
1278	}
1279	}	1774	}
1280		1775
1281	sub child {	1776	sub child {
		1777	eval q{ # poor man's autoloading {}
		1778	*_sigchld = sub {
		1779	my $pid;
		1780
		1781	AnyEvent->_emit_childstatus ($pid, $?)
		1782	while ($pid = waitpid -1, WNOHANG) > 0;
		1783	};
		1784
		1785	*child = sub {
1282	my (undef, %arg) = @_;	1786	my (undef, %arg) = @_;
1283		1787
1284	defined (my $pid = $arg{pid} + 0)	1788	my $pid = $arg{pid};
1285	or Carp::croak "required option 'pid' is missing";	1789	my $cb = $arg{cb};
1286		1790
1287	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1791	$PID_CB{$pid}{$cb+0} = $cb;
1288		1792
1289	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1290
1291	unless ($CHLD_W) {	1793	unless ($CHLD_W) {
1292	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1794	$CHLD_W = AE::signal CHLD => \&_sigchld;
1293	# child could be a zombie already, so make at least one round	1795	# child could be a zombie already, so make at least one round
1294	&_sigchld;	1796	&_sigchld;
1295	}	1797	}
1296		1798
1297	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1799	bless [$pid, $cb+0], "AnyEvent::Base::child"
1298	}	1800	};
1299		1801
1300	sub AnyEvent::Base::child::DESTROY {	1802	*AnyEvent::Base::child::DESTROY = sub {
1301	my ($pid, $cb) = @{$_[0]};	1803	my ($pid, $icb) = @{$_[0]};
1302		1804
1303	delete $PID_CB{$pid}{$cb};	1805	delete $PID_CB{$pid}{$icb};
1304	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1806	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1305		1807
1306	undef $CHLD_W unless keys %PID_CB;	1808	undef $CHLD_W unless keys %PID_CB;
		1809	};
		1810	};
		1811	die if $@;
		1812
		1813	&child
1307	}	1814	}
1308		1815
1309	# idle emulation is done by simply using a timer, regardless	1816	# idle emulation is done by simply using a timer, regardless
1310	# of whether the process is idle or not, and not letting	1817	# of whether the process is idle or not, and not letting
1311	# the callback use more than 50% of the time.	1818	# the callback use more than 50% of the time.
1312	sub idle {	1819	sub idle {
		1820	eval q{ # poor man's autoloading {}
		1821	*idle = sub {
1313	my (undef, %arg) = @_;	1822	my (undef, %arg) = @_;
1314		1823
1315	my ($cb, $w, $rcb) = $arg{cb};	1824	my ($cb, $w, $rcb) = $arg{cb};
1316		1825
1317	$rcb = sub {	1826	$rcb = sub {
1318	if ($cb) {	1827	if ($cb) {
1319	$w = _time;	1828	$w = AE::time;
1320	&$cb;	1829	&$cb;
1321	$w = _time - $w;	1830	$w = AE::time - $w;
1322		1831
1323	# never use more then 50% of the time for the idle watcher,	1832	# never use more then 50% of the time for the idle watcher,
1324	# within some limits	1833	# within some limits
1325	$w = 0.0001 if $w < 0.0001;	1834	$w = 0.0001 if $w < 0.0001;
1326	$w = 5 if $w > 5;	1835	$w = 5 if $w > 5;
1327		1836
1328	$w = AnyEvent->timer (after => $w, cb => $rcb);	1837	$w = AE::timer $w, 0, $rcb;
1329	} else {	1838	} else {
1330	# clean up...	1839	# clean up...
1331	undef $w;	1840	undef $w;
1332	undef $rcb;	1841	undef $rcb;
		1842	}
		1843	};
		1844
		1845	$w = AE::timer 0.05, 0, $rcb;
		1846
		1847	bless \\$cb, "AnyEvent::Base::idle"
1333	}	1848	};
		1849
		1850	*AnyEvent::Base::idle::DESTROY = sub {
		1851	undef $${$_[0]};
		1852	};
1334	};	1853	};
		1854	die if $@;
1335		1855
1336	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1856	&idle
1337
1338	bless \\$cb, "AnyEvent::Base::idle"
1339	}
1340
1341	sub AnyEvent::Base::idle::DESTROY {
1342	undef $${$_[0]};
1343	}	1857	}
1344		1858
1345	package AnyEvent::CondVar;	1859	package AnyEvent::CondVar;
1346		1860
1347	our @ISA = AnyEvent::CondVar::Base::;	1861	our @ISA = AnyEvent::CondVar::Base::;
1348		1862
		1863	# only to be used for subclassing
		1864	sub new {
		1865	my $class = shift;
		1866	bless AnyEvent->condvar (@_), $class
		1867	}
		1868
1349	package AnyEvent::CondVar::Base;	1869	package AnyEvent::CondVar::Base;
1350		1870
1351	use overload	1871	#use overload
1352	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1872	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1353	fallback => 1;	1873	# fallback => 1;
		1874
		1875	# save 300+ kilobytes by dirtily hardcoding overloading
		1876	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1877	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1878	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1879	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1880
		1881	our $WAITING;
1354		1882
1355	sub _send {	1883	sub _send {
1356	# nop	1884	# nop
		1885	}
		1886
		1887	sub _wait {
		1888	AnyEvent->_poll until $_[0]{_ae_sent};
1357	}	1889	}
1358		1890
1359	sub send {	1891	sub send {
1360	my $cv = shift;	1892	my $cv = shift;
1361	$cv->{_ae_sent} = [@_];	1893	$cv->{_ae_sent} = [@_];
…		…
1370		1902
1371	sub ready {	1903	sub ready {
1372	$_[0]{_ae_sent}	1904	$_[0]{_ae_sent}
1373	}	1905	}
1374		1906
1375	sub _wait {
1376	AnyEvent->one_event while !$_[0]{_ae_sent};
1377	}
1378
1379	sub recv {	1907	sub recv {
		1908	unless ($_[0]{_ae_sent}) {
		1909	$WAITING
		1910	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1911
		1912	local $WAITING = 1;
1380	$_[0]->_wait;	1913	$_[0]->_wait;
		1914	}
1381		1915
1382	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1916	$_[0]{_ae_croak}
1383	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1917	and Carp::croak $_[0]{_ae_croak};
		1918
		1919	wantarray
		1920	? @{ $_[0]{_ae_sent} }
		1921	: $_[0]{_ae_sent}[0]
1384	}	1922	}
1385		1923
1386	sub cb {	1924	sub cb {
1387	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1925	my $cv = shift;
		1926
		1927	@_
		1928	and $cv->{_ae_cb} = shift
		1929	and $cv->{_ae_sent}
		1930	and (delete $cv->{_ae_cb})->($cv);
		1931
1388	$_[0]{_ae_cb}	1932	$cv->{_ae_cb}
1389	}	1933	}
1390		1934
1391	sub begin {	1935	sub begin {
1392	++$_[0]{_ae_counter};	1936	++$_[0]{_ae_counter};
1393	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1937	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1398	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1942	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1399	}	1943	}
1400		1944
1401	# undocumented/compatibility with pre-3.4	1945	# undocumented/compatibility with pre-3.4
1402	*broadcast = \&send;	1946	*broadcast = \&send;
1403	*wait = \&_wait;	1947	*wait = \&recv;
1404		1948
1405	=head1 ERROR AND EXCEPTION HANDLING	1949	=head1 ERROR AND EXCEPTION HANDLING
1406		1950
1407	In general, AnyEvent does not do any error handling - it relies on the	1951	In general, AnyEvent does not do any error handling - it relies on the
1408	caller to do that if required. The L<AnyEvent::Strict> module (see also	1952	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1435		1979
1436	By default, AnyEvent will be completely silent except in fatal	1980	By default, AnyEvent will be completely silent except in fatal
1437	conditions. You can set this environment variable to make AnyEvent more	1981	conditions. You can set this environment variable to make AnyEvent more
1438	talkative.	1982	talkative.
1439		1983
1440	When set to C<1> or higher, causes AnyEvent to warn about unexpected	1984	When set to C<5> or higher, causes AnyEvent to warn about unexpected
1441	conditions, such as not being able to load the event model specified by	1985	conditions, such as not being able to load the event model specified by
1442	C<PERL_ANYEVENT_MODEL>.	1986	C<PERL_ANYEVENT_MODEL>.
1443		1987
1444	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1988	When set to C<7> or higher, cause AnyEvent to report to STDERR which event
1445	model it chooses.	1989	model it chooses.
		1990
		1991	When set to C<8> or higher, then AnyEvent will report extra information on
		1992	which optional modules it loads and how it implements certain features.
1446		1993
1447	=item C<PERL_ANYEVENT_STRICT>	1994	=item C<PERL_ANYEVENT_STRICT>
1448		1995
1449	AnyEvent does not do much argument checking by default, as thorough	1996	AnyEvent does not do much argument checking by default, as thorough
1450	argument checking is very costly. Setting this variable to a true value	1997	argument checking is very costly. Setting this variable to a true value
…		…
1452	check the arguments passed to most method calls. If it finds any problems,	1999	check the arguments passed to most method calls. If it finds any problems,
1453	it will croak.	2000	it will croak.
1454		2001
1455	In other words, enables "strict" mode.	2002	In other words, enables "strict" mode.
1456		2003
1457	Unlike C<use strict>, it is definitely recommended to keep it off in	2004	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1458	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2005	>>, it is definitely recommended to keep it off in production. Keeping
1459	developing programs can be very useful, however.	2006	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2007	can be very useful, however.
		2008
		2009	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2010
		2011	If this env variable is set, then its contents will be interpreted by
		2012	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		2013	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		2014	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		2015
		2016	This takes place when the first watcher is created.
		2017
		2018	For example, to bind a debug shell on a unix domain socket in
		2019	F<< /tmp/debug<pid>.sock >>, you could use this:
		2020
		2021	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2022
		2023	Note that creating sockets in F</tmp> is very unsafe on multiuser
		2024	systems.
		2025
		2026	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2027
		2028	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2029	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1460		2030
1461	=item C<PERL_ANYEVENT_MODEL>	2031	=item C<PERL_ANYEVENT_MODEL>
1462		2032
1463	This can be used to specify the event model to be used by AnyEvent, before	2033	This can be used to specify the event model to be used by AnyEvent, before
1464	auto detection and -probing kicks in. It must be a string consisting	2034	auto detection and -probing kicks in.
1465	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2035
		2036	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2037	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1466	and the resulting module name is loaded and if the load was successful,	2038	resulting module name is loaded and - if the load was successful - used as
1467	used as event model. If it fails to load AnyEvent will proceed with	2039	event model backend. If it fails to load then AnyEvent will proceed with
1468	auto detection and -probing.	2040	auto detection and -probing.
1469		2041
1470	This functionality might change in future versions.	2042	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2043	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2044	the end of a string designates a module name and quotes it appropriately).
1471		2045
1472	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2046	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1473	could start your program like this:	2047	could start your program like this:
1474		2048
1475	PERL_ANYEVENT_MODEL=Perl perl ...	2049	PERL_ANYEVENT_MODEL=Perl perl ...
1476		2050
1477	=item C<PERL_ANYEVENT_PROTOCOLS>	2051	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1526		2100
1527	When neither C<ca_file> nor C<ca_path> was specified during	2101	When neither C<ca_file> nor C<ca_path> was specified during
1528	L<AnyEvent::TLS> context creation, and either of these environment	2102	L<AnyEvent::TLS> context creation, and either of these environment
1529	variables exist, they will be used to specify CA certificate locations	2103	variables exist, they will be used to specify CA certificate locations
1530	instead of a system-dependent default.	2104	instead of a system-dependent default.
		2105
		2106	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2107
		2108	When these are set to C<1>, then the respective modules are not
		2109	loaded. Mostly good for testing AnyEvent itself.
1531		2110
1532	=back	2111	=back
1533		2112
1534	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2113	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1535		2114
…		…
1593	warn "read: $input\n"; # output what has been read	2172	warn "read: $input\n"; # output what has been read
1594	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2173	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1595	},	2174	},
1596	);	2175	);
1597		2176
1598	my $time_watcher; # can only be used once
1599
1600	sub new_timer {
1601	$timer = AnyEvent->timer (after => 1, cb => sub {	2177	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1602	warn "timeout\n"; # print 'timeout' about every second	2178	warn "timeout\n"; # print 'timeout' at most every second
1603	&new_timer; # and restart the time
1604	});	2179	});
1605	}
1606
1607	new_timer; # create first timer
1608		2180
1609	$cv->recv; # wait until user enters /^q/i	2181	$cv->recv; # wait until user enters /^q/i
1610		2182
1611	=head1 REAL-WORLD EXAMPLE	2183	=head1 REAL-WORLD EXAMPLE
1612		2184
…		…
1685		2257
1686	The actual code goes further and collects all errors (C<die>s, exceptions)	2258	The actual code goes further and collects all errors (C<die>s, exceptions)
1687	that occurred during request processing. The C<result> method detects	2259	that occurred during request processing. The C<result> method detects
1688	whether an exception as thrown (it is stored inside the $txn object)	2260	whether an exception as thrown (it is stored inside the $txn object)
1689	and just throws the exception, which means connection errors and other	2261	and just throws the exception, which means connection errors and other
1690	problems get reported tot he code that tries to use the result, not in a	2262	problems get reported to the code that tries to use the result, not in a
1691	random callback.	2263	random callback.
1692		2264
1693	All of this enables the following usage styles:	2265	All of this enables the following usage styles:
1694		2266
1695	1. Blocking:	2267	1. Blocking:
…		…
1743	through AnyEvent. The benchmark creates a lot of timers (with a zero	2315	through AnyEvent. The benchmark creates a lot of timers (with a zero
1744	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2316	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1745	which it is), lets them fire exactly once and destroys them again.	2317	which it is), lets them fire exactly once and destroys them again.
1746		2318
1747	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2319	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1748	distribution.	2320	distribution. It uses the L<AE> interface, which makes a real difference
		2321	for the EV and Perl backends only.
1749		2322
1750	=head3 Explanation of the columns	2323	=head3 Explanation of the columns
1751		2324
1752	I<watcher> is the number of event watchers created/destroyed. Since	2325	I<watcher> is the number of event watchers created/destroyed. Since
1753	different event models feature vastly different performances, each event	2326	different event models feature vastly different performances, each event
…		…
1774	watcher.	2347	watcher.
1775		2348
1776	=head3 Results	2349	=head3 Results
1777		2350
1778	name watchers bytes create invoke destroy comment	2351	name watchers bytes create invoke destroy comment
1779	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2352	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1780	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2353	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1781	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2354	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1782	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2355	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1783	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2356	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1784	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2357	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1785	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2358	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1786	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2359	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1787	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2360	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1788	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2361	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1789	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2362	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1790	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2363	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1791		2364
1792	=head3 Discussion	2365	=head3 Discussion
1793		2366
1794	The benchmark does I<not> measure scalability of the event loop very	2367	The benchmark does I<not> measure scalability of the event loop very
1795	well. For example, a select-based event loop (such as the pure perl one)	2368	well. For example, a select-based event loop (such as the pure perl one)
…		…
1807	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2380	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1808	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2381	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1809	cycles with POE.	2382	cycles with POE.
1810		2383
1811	C<EV> is the sole leader regarding speed and memory use, which are both	2384	C<EV> is the sole leader regarding speed and memory use, which are both
1812	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2385	maximal/minimal, respectively. When using the L<AE> API there is zero
		2386	overhead (when going through the AnyEvent API create is about 5-6 times
		2387	slower, with other times being equal, so still uses far less memory than
1813	far less memory than any other event loop and is still faster than Event	2388	any other event loop and is still faster than Event natively).
1814	natively.
1815		2389
1816	The pure perl implementation is hit in a few sweet spots (both the	2390	The pure perl implementation is hit in a few sweet spots (both the
1817	constant timeout and the use of a single fd hit optimisations in the perl	2391	constant timeout and the use of a single fd hit optimisations in the perl
1818	interpreter and the backend itself). Nevertheless this shows that it	2392	interpreter and the backend itself). Nevertheless this shows that it
1819	adds very little overhead in itself. Like any select-based backend its	2393	adds very little overhead in itself. Like any select-based backend its
…		…
1867	(even when used without AnyEvent), but most event loops have acceptable	2441	(even when used without AnyEvent), but most event loops have acceptable
1868	performance with or without AnyEvent.	2442	performance with or without AnyEvent.
1869		2443
1870	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2444	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1871	the actual event loop, only with extremely fast event loops such as EV	2445	the actual event loop, only with extremely fast event loops such as EV
1872	adds AnyEvent significant overhead.	2446	does AnyEvent add significant overhead.
1873		2447
1874	=item * You should avoid POE like the plague if you want performance or	2448	=item * You should avoid POE like the plague if you want performance or
1875	reasonable memory usage.	2449	reasonable memory usage.
1876		2450
1877	=back	2451	=back
…		…
1893	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2467	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1894	(1%) are active. This mirrors the activity of large servers with many	2468	(1%) are active. This mirrors the activity of large servers with many
1895	connections, most of which are idle at any one point in time.	2469	connections, most of which are idle at any one point in time.
1896		2470
1897	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2471	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1898	distribution.	2472	distribution. It uses the L<AE> interface, which makes a real difference
		2473	for the EV and Perl backends only.
1899		2474
1900	=head3 Explanation of the columns	2475	=head3 Explanation of the columns
1901		2476
1902	I<sockets> is the number of sockets, and twice the number of "servers" (as	2477	I<sockets> is the number of sockets, and twice the number of "servers" (as
1903	each server has a read and write socket end).	2478	each server has a read and write socket end).
…		…
1911	a new one that moves the timeout into the future.	2486	a new one that moves the timeout into the future.
1912		2487
1913	=head3 Results	2488	=head3 Results
1914		2489
1915	name sockets create request	2490	name sockets create request
1916	EV 20000 69.01 11.16	2491	EV 20000 62.66 7.99
1917	Perl 20000 73.32 35.87	2492	Perl 20000 68.32 32.64
1918	IOAsync 20000 157.00 98.14 epoll	2493	IOAsync 20000 174.06 101.15 epoll
1919	IOAsync 20000 159.31 616.06 poll	2494	IOAsync 20000 174.67 610.84 poll
1920	Event 20000 212.62 257.32	2495	Event 20000 202.69 242.91
1921	Glib 20000 651.16 1896.30	2496	Glib 20000 557.01 1689.52
1922	POE 20000 349.67 12317.24 uses POE::Loop::Event	2497	POE 20000 341.54 12086.32 uses POE::Loop::Event
1923		2498
1924	=head3 Discussion	2499	=head3 Discussion
1925		2500
1926	This benchmark I<does> measure scalability and overall performance of the	2501	This benchmark I<does> measure scalability and overall performance of the
1927	particular event loop.	2502	particular event loop.
…		…
2053	As you can see, the AnyEvent + EV combination even beats the	2628	As you can see, the AnyEvent + EV combination even beats the
2054	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2629	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2055	backend easily beats IO::Lambda and POE.	2630	backend easily beats IO::Lambda and POE.
2056		2631
2057	And even the 100% non-blocking version written using the high-level (and	2632	And even the 100% non-blocking version written using the high-level (and
2058	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2633	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2059	large margin, even though it does all of DNS, tcp-connect and socket I/O	2634	higher level ("unoptimised") abstractions by a large margin, even though
2060	in a non-blocking way.	2635	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2061		2636
2062	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2637	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2063	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2638	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2064	part of the IO::lambda distribution and were used without any changes.	2639	part of the IO::Lambda distribution and were used without any changes.
2065		2640
2066		2641
2067	=head1 SIGNALS	2642	=head1 SIGNALS
2068		2643
2069	AnyEvent currently installs handlers for these signals:	2644	AnyEvent currently installs handlers for these signals:
…		…
2074		2649
2075	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2650	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2076	emulation for event loops that do not support them natively. Also, some	2651	emulation for event loops that do not support them natively. Also, some
2077	event loops install a similar handler.	2652	event loops install a similar handler.
2078		2653
2079	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2654	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2080	reset it to default, to avoid losing child exit statuses.	2655	AnyEvent will reset it to default, to avoid losing child exit statuses.
2081		2656
2082	=item SIGPIPE	2657	=item SIGPIPE
2083		2658
2084	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2659	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2085	when AnyEvent gets loaded.	2660	when AnyEvent gets loaded.
…		…
2103	if $SIG{CHLD} eq 'IGNORE';	2678	if $SIG{CHLD} eq 'IGNORE';
2104		2679
2105	$SIG{PIPE} = sub { }	2680	$SIG{PIPE} = sub { }
2106	unless defined $SIG{PIPE};	2681	unless defined $SIG{PIPE};
2107		2682
		2683	=head1 RECOMMENDED/OPTIONAL MODULES
		2684
		2685	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2686	its built-in modules) are required to use it.
		2687
		2688	That does not mean that AnyEvent won't take advantage of some additional
		2689	modules if they are installed.
		2690
		2691	This section explains which additional modules will be used, and how they
		2692	affect AnyEvent's operation.
		2693
		2694	=over 4
		2695
		2696	=item L<Async::Interrupt>
		2697
		2698	This slightly arcane module is used to implement fast signal handling: To
		2699	my knowledge, there is no way to do completely race-free and quick
		2700	signal handling in pure perl. To ensure that signals still get
		2701	delivered, AnyEvent will start an interval timer to wake up perl (and
		2702	catch the signals) with some delay (default is 10 seconds, look for
		2703	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2704
		2705	If this module is available, then it will be used to implement signal
		2706	catching, which means that signals will not be delayed, and the event loop
		2707	will not be interrupted regularly, which is more efficient (and good for
		2708	battery life on laptops).
		2709
		2710	This affects not just the pure-perl event loop, but also other event loops
		2711	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2712
		2713	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2714	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2715	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2716	does nothing for those backends.
		2717
		2718	=item L<EV>
		2719
		2720	This module isn't really "optional", as it is simply one of the backend
		2721	event loops that AnyEvent can use. However, it is simply the best event
		2722	loop available in terms of features, speed and stability: It supports
		2723	the AnyEvent API optimally, implements all the watcher types in XS, does
		2724	automatic timer adjustments even when no monotonic clock is available,
		2725	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2726	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2727	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2728
		2729	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2730	then this module will do nothing for you.
		2731
		2732	=item L<Guard>
		2733
		2734	The guard module, when used, will be used to implement
		2735	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2736	lot less memory), but otherwise doesn't affect guard operation much. It is
		2737	purely used for performance.
		2738
		2739	=item L<JSON> and L<JSON::XS>
		2740
		2741	One of these modules is required when you want to read or write JSON data
		2742	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2743	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2744
		2745	=item L<Net::SSLeay>
		2746
		2747	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2748	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2749	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2750
		2751	=item L<Time::HiRes>
		2752
		2753	This module is part of perl since release 5.008. It will be used when the
		2754	chosen event library does not come with a timing source of its own. The
		2755	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2756	try to use a monotonic clock for timing stability.
		2757
		2758	=back
		2759
		2760
2108	=head1 FORK	2761	=head1 FORK
2109		2762
2110	Most event libraries are not fork-safe. The ones who are usually are	2763	Most event libraries are not fork-safe. The ones who are usually are
2111	because they rely on inefficient but fork-safe C<select> or C<poll>	2764	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2112	calls. Only L<EV> is fully fork-aware.	2765	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2766	are usually badly thought-out hacks that are incompatible with fork in
		2767	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2768	continue event-processing in both parent and child (or both, if you know
		2769	what you are doing).
		2770
		2771	This means that, in general, you cannot fork and do event processing in
		2772	the child if the event library was initialised before the fork (which
		2773	usually happens when the first AnyEvent watcher is created, or the library
		2774	is loaded).
2113		2775
2114	If you have to fork, you must either do so I<before> creating your first	2776	If you have to fork, you must either do so I<before> creating your first
2115	watcher OR you must not use AnyEvent at all in the child.	2777	watcher OR you must not use AnyEvent at all in the child OR you must do
		2778	something completely out of the scope of AnyEvent.
		2779
		2780	The problem of doing event processing in the parent I<and> the child
		2781	is much more complicated: even for backends that I<are> fork-aware or
		2782	fork-safe, their behaviour is not usually what you want: fork clones all
		2783	watchers, that means all timers, I/O watchers etc. are active in both
		2784	parent and child, which is almost never what you want. USing C<exec>
		2785	to start worker children from some kind of manage rprocess is usually
		2786	preferred, because it is much easier and cleaner, at the expense of having
		2787	to have another binary.
2116		2788
2117		2789
2118	=head1 SECURITY CONSIDERATIONS	2790	=head1 SECURITY CONSIDERATIONS
2119		2791
2120	AnyEvent can be forced to load any event model via	2792	AnyEvent can be forced to load any event model via
…		…
2150	pronounced).	2822	pronounced).
2151		2823
2152		2824
2153	=head1 SEE ALSO	2825	=head1 SEE ALSO
2154		2826
2155	Utility functions: L<AnyEvent::Util>.	2827	Tutorial/Introduction: L<AnyEvent::Intro>.
2156		2828
2157	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2829	FAQ: L<AnyEvent::FAQ>.
2158	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2830
		2831	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2832	(simply logging).
		2833
		2834	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2835	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2836
		2837	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2838	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2839	L<Qt>, L<POE>, L<FLTK>.
2159		2840
2160	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2841	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2161	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2842	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2162	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2843	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2163	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2844	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		2845	L<AnyEvent::Impl::FLTK>.
2164		2846
2165	Non-blocking file handles, sockets, TCP clients and	2847	Non-blocking handles, pipes, stream sockets, TCP clients and
2166	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2848	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2167		2849
2168	Asynchronous DNS: L<AnyEvent::DNS>.	2850	Asynchronous DNS: L<AnyEvent::DNS>.
2169		2851
2170	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2852	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2171	L<Coro::Event>,
2172		2853
2173	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2854	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2174	L<AnyEvent::HTTP>.	2855	L<AnyEvent::HTTP>.
2175		2856
2176		2857
2177	=head1 AUTHOR	2858	=head1 AUTHOR
2178		2859

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