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Revision 1.332 by root, Tue Aug 31 23:32:40 2010 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	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		56
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		58
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	76	module users into the same thing by forcing them to use the same event
66	model you use.	77	model you use.
67		78
68	For modules like POE or IO::Async (which is a total misnomer as it is	79	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	80	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	81	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	82	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	83	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.	84	module are I<also> forced to use the same event loop you use.
74		85
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	86	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	87	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	88	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
78	your module uses one of those, every user of your module has to use it,	89	your module uses one of those, every user of your module has to use it,
79	too. But if your module uses AnyEvent, it works transparently with all	90	too. But if your module uses AnyEvent, it works transparently with all
80	event models it supports (including stuff like IO::Async, as long as those	91	event models it supports (including stuff like IO::Async, as long as those
81	use one of the supported event loops. It is trivial to add new event loops	92	use one of the supported event loops. It is easy to add new event loops
82	to AnyEvent, too, so it is future-proof).	93	to AnyEvent, too, so it is future-proof).
83		94
84	In addition to being free of having to use I<the one and only true event	95	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	96	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	97	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	98	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	99	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	100	technically possible.
90		101
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	102	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	103	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	109	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	110	model, you should I<not> use this module.
100		111
101	=head1 DESCRIPTION	112	=head1 DESCRIPTION
102		113
103	L<AnyEvent> provides an identical interface to multiple event loops. This	114	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	115	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	116	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	117	than one event loop cannot coexist peacefully).
107		118
108	The interface itself is vaguely similar, but not identical to the L<Event>	119	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	120	module.
110		121
111	During the first call of any watcher-creation method, the module tries	122	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	123	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	124	following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	125	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	126	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	127	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	128	available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	129	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		130
122	Because AnyEvent first checks for modules that are already loaded, loading	131	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	132	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	133	that model the default. For example:
125		134
…		…
127	use AnyEvent;	136	use AnyEvent;
128		137
129	# .. AnyEvent will likely default to Tk	138	# .. AnyEvent will likely default to Tk
130		139
131	The I<likely> means that, if any module loads another event model and	140	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	141	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...	142	as very few modules hardcode event loops without announcing this very
		143	loudly.
134		144
135	The pure-perl implementation of AnyEvent is called	145	The pure-perl implementation of AnyEvent is called
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	146	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
137	explicitly and enjoy the high availability of that event loop :)	147	explicitly and enjoy the high availability of that event loop :)
138		148
…		…
147	callback when the event occurs (of course, only when the event model	157	callback when the event occurs (of course, only when the event model
148	is in control).	158	is in control).
149		159
150	Note that B<callbacks must not permanently change global variables>	160	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	161	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	162	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	163	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	164	widely between event loops.
155		165
156	To disable the watcher you have to destroy it (e.g. by setting the	166	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	167	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	168	to it).
159		169
160	All watchers are created by calling a method on the C<AnyEvent> class.	170	All watchers are created by calling a method on the C<AnyEvent> class.
161		171
162	Many watchers either are used with "recursion" (repeating timers for	172	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	173	example), or need to refer to their watcher object in other ways.
164		174
165	An any way to achieve that is this pattern:	175	One way to achieve that is this pattern:
166		176
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	177	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	178	# you can use $w here, for example to undef it
169	undef $w;	179	undef $w;
170	});	180	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	182	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	183	my variables are only visible after the statement in which they are
174	declared.	184	declared.
175		185
176	=head2 I/O WATCHERS	186	=head2 I/O WATCHERS
		187
		188	$w = AnyEvent->io (
		189	fh => <filehandle_or_fileno>,
		190	poll => <"r" or "w">,
		191	cb => <callback>,
		192	);
177		193
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	194	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	195	with the following mandatory key-value pairs as arguments:
180		196
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	197	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
196		212
197	The I/O watcher might use the underlying file descriptor or a copy of it.	213	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	214	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	215	underlying file descriptor.
200		216
201	Some event loops issue spurious readyness notifications, so you should	217	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	218	always use non-blocking calls when reading/writing from/to your file
203	handles.	219	handles.
204		220
205	Example: wait for readability of STDIN, then read a line and disable the	221	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	222	watcher.
…		…
211	undef $w;	227	undef $w;
212	});	228	});
213		229
214	=head2 TIME WATCHERS	230	=head2 TIME WATCHERS
215		231
		232	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		233
		234	$w = AnyEvent->timer (
		235	after => <fractional_seconds>,
		236	interval => <fractional_seconds>,
		237	cb => <callback>,
		238	);
		239
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	240	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	241	method with the following mandatory arguments:
218		242
219	C<after> specifies after how many seconds (fractional values are	243	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	244	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		246
223	Although the callback might get passed parameters, their value and	247	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	248	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	249	callbacks cannot use arguments passed to time watcher callbacks.
226		250
227	The callback will normally be invoked once only. If you specify another	251	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	252	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	253	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	254	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	255	false value, then it is treated as if it were not specified at all.
232		256
233	The callback will be rescheduled before invoking the callback, but no	257	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	258	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	259	only approximate.
236		260
237	Example: fire an event after 7.7 seconds.	261	Example: fire an event after 7.7 seconds.
238		262
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	263	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		281
258	While most event loops expect timers to specified in a relative way, they	282	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	283	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	284	"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	285	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.	286	fire "after a second" might actually take six years to finally fire.
263		287
264	AnyEvent cannot compensate for this. The only event loop that is conscious	288	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	289	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)	290	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	291	timers.
268		292
269	AnyEvent always prefers relative timers, if available, matching the	293	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	294	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	316	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.>	317	function to call when you want to know the current time.>
294		318
295	This function is also often faster then C<< AnyEvent->time >>, and	319	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	320	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	321	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		322
299	The rest of this section is only of relevance if you try to be very exact	323	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.	324	with your timing; you can skip it without a bad conscience.
301		325
302	For a practical example of when these times differ, consider L<Event::Lib>	326	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	327	and L<EV> and the following set-up:
304		328
305	The event loop is running and has just invoked one of your callback at	329	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,	330	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	331	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	332	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	333	after three seconds.
310		334
…		…
341	might affect timers and time-outs.	365	might affect timers and time-outs.
342		366
343	When this is the case, you can call this method, which will update the	367	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	368	event loop's idea of "current time".
345		369
		370	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		371	when mod_perl executes the script, then the event loop will have the wrong
		372	idea about the "current time" (being potentially far in the past, when the
		373	script ran the last time). In that case you should arrange a call to C<<
		374	AnyEvent->now_update >> each time the web server process wakes up again
		375	(e.g. at the start of your script, or in a handler).
		376
346	Note that updating the time I<might> cause some events to be handled.	377	Note that updating the time I<might> cause some events to be handled.
347		378
348	=back	379	=back
349		380
350	=head2 SIGNAL WATCHERS	381	=head2 SIGNAL WATCHERS
		382
		383	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		384
352	You can watch for signals using a signal watcher, C<signal> is the signal	385	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	386	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	387	callback to be invoked whenever a signal occurs.
355		388
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	394	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	395	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.	396	but it is guaranteed not to interrupt any other callbacks.
364		397
365	The main advantage of using these watchers is that you can share a signal	398	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	399	between multiple watchers, and AnyEvent will ensure that signals will not
		400	interrupt your program at bad times.
367		401
368	This watcher might use C<%SIG>, so programs overwriting those signals	402	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	403	so programs overwriting those signals directly will likely not work
		404	correctly.
370		405
371	Example: exit on SIGINT	406	Example: exit on SIGINT
372		407
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	408	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		409
		410	=head3 Restart Behaviour
		411
		412	While restart behaviour is up to the event loop implementation, most will
		413	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		414	pure perl implementation).
		415
		416	=head3 Safe/Unsafe Signals
		417
		418	Perl signals can be either "safe" (synchronous to opcode handling) or
		419	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		420	latter might corrupt your memory.
		421
		422	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		423	i.e. they will not interrupt your running perl program but will only be
		424	called as part of the normal event handling (just like timer, I/O etc.
		425	callbacks, too).
		426
		427	=head3 Signal Races, Delays and Workarounds
		428
		429	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		430	callbacks to signals in a generic way, which is a pity, as you cannot
		431	do race-free signal handling in perl, requiring C libraries for
		432	this. AnyEvent will try to do its best, which means in some cases,
		433	signals will be delayed. The maximum time a signal might be delayed is
		434	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		435	variable can be changed only before the first signal watcher is created,
		436	and should be left alone otherwise. This variable determines how often
		437	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		438	will cause fewer spurious wake-ups, which is better for power and CPU
		439	saving.
		440
		441	All these problems can be avoided by installing the optional
		442	L<Async::Interrupt> module, which works with most event loops. It will not
		443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		444	(and not with L<POE> currently, as POE does its own workaround with
		445	one-second latency). For those, you just have to suffer the delays.
		446
375	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
376		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
377	You can also watch on a child process exit and catch its exit status.	451	You can also watch for a child process exit and catch its exit status.
378		452
379	The child process is specified by the C<pid> argument (if set to C<0>, it	453	The child process is specified by the C<pid> argument (on some backends,
380	watches for any child process exit). The watcher will triggered only when	454	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	455	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	456	finished and an exit status is available, not on any trace events
		457	(stopped/continued).
383		458
384	The callback will be called with the pid and exit status (as returned by	459	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	460	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	461	callback arguments.
387		462
…		…
403		478
404	This means you cannot create a child watcher as the very first	479	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	480	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	481	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	482	C<AnyEvent::detect>).
		483
		484	As most event loops do not support waiting for child events, they will be
		485	emulated by AnyEvent in most cases, in which the latency and race problems
		486	mentioned in the description of signal watchers apply.
408		487
409	Example: fork a process and wait for it	488	Example: fork a process and wait for it
410		489
411	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
412		491
…		…
424	# do something else, then wait for process exit	503	# do something else, then wait for process exit
425	$done->recv;	504	$done->recv;
426		505
427	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
428		507
429	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		509
434	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	511	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		512
438	Most event loops unfortunately do not really support idle watchers (only	513	Idle watchers are useful when there is a need to do something, but it
		514	is not so important (or wise) to do it instantly. The callback will be
		515	invoked only when there is "nothing better to do", which is usually
		516	defined as "all outstanding events have been handled and no new events
		517	have been detected". That means that idle watchers ideally get invoked
		518	when the event loop has just polled for new events but none have been
		519	detected. Instead of blocking to wait for more events, the idle watchers
		520	will be invoked.
		521
		522	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
441		525
442	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	527	program is otherwise idle:
…		…
459	});	543	});
460	});	544	});
461		545
462	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
463		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
464	If you are familiar with some event loops you will know that all of them	553	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	554	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
467		556
468	AnyEvent is different, it expects somebody else to run the event loop and	557	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	558	loop and will only block when necessary (usually when told by the user).
470		559
471	The instrument to do that is called a "condition variable", so called	560	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	561	they represent a condition that must become true.
		562
		563	Now is probably a good time to look at the examples further below.
473		564
474	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	567	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	568	becomes true, with the condition variable as the first argument (but not
479	the results).	569	the results).
480		570
481	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
482	by calling the C<send> method (or calling the condition variable as if it	572	by calling the C<send> method (or calling the condition variable as if it
483	were a callback, read about the caveats in the description for the C<<	573	were a callback, read about the caveats in the description for the C<<
484	->send >> method).	574	->send >> method).
485		575
486	Condition variables are similar to callbacks, except that you can	576	Since condition variables are the most complex part of the AnyEvent API, here are
487	optionally wait for them. They can also be called merge points - points	577	some different mental models of what they are - pick the ones you can connect to:
488	in time where multiple outstanding events have been processed. And yet	578
489	another way to call them is transactions - each condition variable can be	579	=over 4
490	used to represent a transaction, which finishes at some point and delivers	580
491	a result.	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
		582	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		583
		584	=item * Condition variables are signals - one side can emit or send them,
		585	the other side can wait for them, or install a handler that is called when
		586	the signal fires.
		587
		588	=item * Condition variables are like "Merge Points" - points in your program
		589	where you merge multiple independent results/control flows into one.
		590
		591	=item * Condition variables represent a transaction - functions that start
		592	some kind of transaction can return them, leaving the caller the choice
		593	between waiting in a blocking fashion, or setting a callback.
		594
		595	=item * Condition variables represent future values, or promises to deliver
		596	some result, long before the result is available.
		597
		598	=back
492		599
493	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	601	for example, if you write a module that does asynchronous http requests,
495	then a condition variable would be the ideal candidate to signal the	602	then a condition variable would be the ideal candidate to signal the
496	availability of results. The user can either act when the callback is	603	availability of results. The user can either act when the callback is
…		…
509		616
510	Condition variables are represented by hash refs in perl, and the keys	617	Condition variables are represented by hash refs in perl, and the keys
511	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	618	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
512	easy (it is often useful to build your own transaction class on top of	619	easy (it is often useful to build your own transaction class on top of
513	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	620	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
514	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
515		622
516	There are two "sides" to a condition variable - the "producer side" which	623	There are two "sides" to a condition variable - the "producer side" which
517	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	625	for the send to occur.
519		626
520	Example: wait for a timer.	627	Example: wait for a timer.
521		628
522	# wait till the result is ready	629	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
524		631
525	# do something such as adding a timer	632	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
527	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
530	after => 1,	637	after => 1,
531	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
532	);	639	);
533		640
534	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
535	# calls send	642	# calls ->send
536	$result_ready->recv;	643	$timer_fired->recv;
537		644
538	Example: wait for a timer, but take advantage of the fact that	645	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	646	variables are also callable directly.
540		647
541	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	649	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	650	$done->recv;
544		651
…		…
550		657
551	...	658	...
552		659
553	my @info = $couchdb->info->recv;	660	my @info = $couchdb->info->recv;
554		661
555	And this is how you would just ste a callback to be called whenever the	662	And this is how you would just set a callback to be called whenever the
556	results are available:	663	results are available:
557		664
558	$couchdb->info->cb (sub {	665	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	666	my @info = $_[0]->recv;
560	});	667	});
…		…
578	immediately from within send.	685	immediately from within send.
579		686
580	Any arguments passed to the C<send> call will be returned by all	687	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	688	future C<< ->recv >> calls.
582		689
583	Condition variables are overloaded so one can call them directly	690	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	691	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	692	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		693
592	=item $cv->croak ($error)	694	=item $cv->croak ($error)
593		695
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	696	Similar to send, but causes all calls to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
596		698
597	This can be used to signal any errors to the condition variable	699	This can be used to signal any errors to the condition variable
598	user/consumer.	700	user/consumer. Doing it this way instead of calling C<croak> directly
		701	delays the error detection, but has the overwhelming advantage that it
		702	diagnoses the error at the place where the result is expected, and not
		703	deep in some event callback with no connection to the actual code causing
		704	the problem.
599		705
600	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
601		707
602	=item $cv->end	708	=item $cv->end
603		709
…		…
605	one. For example, a function that pings many hosts in parallel might want	711	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
607		713
608	Every call to C<< ->begin >> will increment a counter, and every call to	714	Every call to C<< ->begin >> will increment a counter, and every call to
609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	715	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
610	>>, the (last) callback passed to C<begin> will be executed. That callback	716	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	717	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	718	>>, but that is not required. If no group callback was set, C<send> will
		719	be called without any arguments.
613		720
614	You can think of C<< $cv->send >> giving you an OR condition (one call	721	You can think of C<< $cv->send >> giving you an OR condition (one call
615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	722	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	723	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		724
…		…
639	one call to C<begin>, so the condvar waits for all calls to C<end> before	746	one call to C<begin>, so the condvar waits for all calls to C<end> before
640	sending.	747	sending.
641		748
642	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
643	there are results to be passwd back, and the number of tasks that are	750	there are results to be passwd back, and the number of tasks that are
644	begung can potentially be zero:	751	begun can potentially be zero:
645		752
646	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
647		754
648	my %result;	755	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
650		757
651	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
652	$cv->begin;	759	$cv->begin;
653	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	761	$result{$host} = ...;
…		…
670	to be called once the counter reaches C<0>, and second, it ensures that	777	to be called once the counter reaches C<0>, and second, it ensures that
671	C<send> is called even when C<no> hosts are being pinged (the loop	778	C<send> is called even when C<no> hosts are being pinged (the loop
672	doesn't execute once).	779	doesn't execute once).
673		780
674	This is the general pattern when you "fan out" into multiple (but	781	This is the general pattern when you "fan out" into multiple (but
675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
676	the callback and ensure C<end> is called at least once, and then, for each	783	the callback and ensure C<end> is called at least once, and then, for each
677	subrequest you start, call C<begin> and for each subrequest you finish,	784	subrequest you start, call C<begin> and for each subrequest you finish,
678	call C<end>.	785	call C<end>.
679		786
680	=back	787	=back
…		…
687	=over 4	794	=over 4
688		795
689	=item $cv->recv	796	=item $cv->recv
690		797
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	800	normally.
694		801
695	You can only wait once on a condition - additional calls are valid but	802	You can only wait once on a condition - additional calls are valid but
696	will return immediately.	803	will return immediately.
697		804
…		…
699	function will call C<croak>.	806	function will call C<croak>.
700		807
701	In list context, all parameters passed to C<send> will be returned,	808	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	809	in scalar context only the first one will be returned.
703		810
		811	Note that doing a blocking wait in a callback is not supported by any
		812	event loop, that is, recursive invocation of a blocking C<< ->recv
		813	>> is not allowed, and the C<recv> call will C<croak> if such a
		814	condition is detected. This condition can be slightly loosened by using
		815	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		816	any thread that doesn't run the event loop itself.
		817
704	Not all event models support a blocking wait - some die in that case	818	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	819	(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	820	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	821	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	823	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
711		825
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	826	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	827	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	828	time). This will work even when the event loop does not support blocking
726	waits otherwise.	829	waits otherwise.
727		830
728	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
734		837
735	This is a mutator function that returns the callback set and optionally	838	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	839	replaces it before doing so.
737		840
738	The callback will be called when the condition becomes "true", i.e. when	841	The callback will be called when the condition becomes "true", i.e. when
739	C<send> or C<croak> are called, with the only argument being the condition	842	C<send> or C<croak> are called, with the only argument being the
740	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
741	is guaranteed not to block.	844	callback is called immediately when it is set. Calling C<recv> inside
		845	the callback or at any later time is guaranteed not to block.
742		846
743	=back	847	=back
744		848
745	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
746		850
…		…
749	=over 4	853	=over 4
750		854
751	=item Backends that are autoprobed when no other event loop can be found.	855	=item Backends that are autoprobed when no other event loop can be found.
752		856
753	EV is the preferred backend when no other event loop seems to be in	857	EV is the preferred backend when no other event loop seems to be in
754	use. If EV is not installed, then AnyEvent will try Event, and, failing	858	use. If EV is not installed, then AnyEvent will fall back to its own
755	that, will fall back to its own pure-perl implementation, which is	859	pure-perl implementation, which is available everywhere as it comes with
756	available everywhere as it comes with AnyEvent itself.	860	AnyEvent itself.
757		861
758	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	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.	863	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
761		864
762	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
763		866
764	These will be used when they are currently loaded when the first watcher	867	These will be used if they are already loaded when the first watcher
765	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
766	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
767	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
768	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
769		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
770	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
771	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
772	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
773	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
774		879
775	=item Backends with special needs.	880	=item Backends with special needs.
776		881
777	Qt requires the Qt::Application to be instantiated first, but will	882	Qt requires the Qt::Application to be instantiated first, but will
778	otherwise be picked up automatically. As long as the main program	883	otherwise be picked up automatically. As long as the main program
…		…
783		888
784	Support for IO::Async can only be partial, as it is too broken and	889	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	890	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	891	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	892	it can only be used by a main program knowing about AnyEvent. See
788	L<AnyEvent::Impl::Async> for the gory details.	893	L<AnyEvent::Impl::IOAsync> for the gory details.
789		894
790	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.	895	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
791		896
792	=item Event loops that are indirectly supported via other backends.	897	=item Event loops that are indirectly supported via other backends.
793		898
…		…
821	Contains C<undef> until the first watcher is being created, before the	926	Contains C<undef> until the first watcher is being created, before the
822	backend has been autodetected.	927	backend has been autodetected.
823		928
824	Afterwards it contains the event model that is being used, which is the	929	Afterwards it contains the event model that is being used, which is the
825	name of the Perl class implementing the model. This class is usually one	930	name of the Perl class implementing the model. This class is usually one
826	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	931	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
827	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	932	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
828	will be C<urxvt::anyevent>).	933	will be C<urxvt::anyevent>).
829		934
830	=item AnyEvent::detect	935	=item AnyEvent::detect
831		936
832	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	937	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
833	if necessary. You should only call this function right before you would	938	if necessary. You should only call this function right before you would
834	have created an AnyEvent watcher anyway, that is, as late as possible at	939	have created an AnyEvent watcher anyway, that is, as late as possible at
835	runtime, and not e.g. while initialising of your module.	940	runtime, and not e.g. during initialisation of your module.
836		941
837	If you need to do some initialisation before AnyEvent watchers are	942	If you need to do some initialisation before AnyEvent watchers are
838	created, use C<post_detect>.	943	created, use C<post_detect>.
839		944
840	=item $guard = AnyEvent::post_detect { BLOCK }	945	=item $guard = AnyEvent::post_detect { BLOCK }
841		946
842	Arranges for the code block to be executed as soon as the event model is	947	Arranges for the code block to be executed as soon as the event model is
843	autodetected (or immediately if this has already happened).	948	autodetected (or immediately if that has already happened).
844		949
845	The block will be executed I<after> the actual backend has been detected	950	The block will be executed I<after> the actual backend has been detected
846	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	951	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
847	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	952	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
848	other initialisations - see the sources of L<AnyEvent::Strict> or	953	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
852	event module detection too early, for example, L<AnyEvent::AIO> creates	957	event module detection too early, for example, L<AnyEvent::AIO> creates
853	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	958	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
854	avoid autodetecting the event module at load time.	959	avoid autodetecting the event module at load time.
855		960
856	If called in scalar or list context, then it creates and returns an object	961	If called in scalar or list context, then it creates and returns an object
857	that automatically removes the callback again when it is destroyed. See	962	that automatically removes the callback again when it is destroyed (or
		963	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
858	L<Coro::BDB> for a case where this is useful.	964	a case where this is useful.
		965
		966	Example: Create a watcher for the IO::AIO module and store it in
		967	C<$WATCHER>, but do so only do so after the event loop is initialised.
		968
		969	our WATCHER;
		970
		971	my $guard = AnyEvent::post_detect {
		972	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		973	};
		974
		975	# the ||= is important in case post_detect immediately runs the block,
		976	# as to not clobber the newly-created watcher. assigning both watcher and
		977	# post_detect guard to the same variable has the advantage of users being
		978	# able to just C<undef $WATCHER> if the watcher causes them grief.
		979
		980	$WATCHER ||= $guard;
859		981
860	=item @AnyEvent::post_detect	982	=item @AnyEvent::post_detect
861		983
862	If there are any code references in this array (you can C<push> to it	984	If there are any code references in this array (you can C<push> to it
863	before or after loading AnyEvent), then they will called directly after	985	before or after loading AnyEvent), then they will be called directly
864	the event loop has been chosen.	986	after the event loop has been chosen.
865		987
866	You should check C<$AnyEvent::MODEL> before adding to this array, though:	988	You should check C<$AnyEvent::MODEL> before adding to this array, though:
867	if it is defined then the event loop has already been detected, and the	989	if it is defined then the event loop has already been detected, and the
868	array will be ignored.	990	array will be ignored.
869		991
870	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	992	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
871	it,as it takes care of these details.	993	it, as it takes care of these details.
872		994
873	This variable is mainly useful for modules that can do something useful	995	This variable is mainly useful for modules that can do something useful
874	when AnyEvent is used and thus want to know when it is initialised, but do	996	when AnyEvent is used and thus want to know when it is initialised, but do
875	not need to even load it by default. This array provides the means to hook	997	not need to even load it by default. This array provides the means to hook
876	into AnyEvent passively, without loading it.	998	into AnyEvent passively, without loading it.
877		999
		1000	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1001	together, you could put this into Coro (this is the actual code used by
		1002	Coro to accomplish this):
		1003
		1004	if (defined $AnyEvent::MODEL) {
		1005	# AnyEvent already initialised, so load Coro::AnyEvent
		1006	require Coro::AnyEvent;
		1007	} else {
		1008	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1009	# as soon as it is
		1010	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1011	}
		1012
878	=back	1013	=back
879		1014
880	=head1 WHAT TO DO IN A MODULE	1015	=head1 WHAT TO DO IN A MODULE
881		1016
882	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1017	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
892	because it will stall the whole program, and the whole point of using	1027	because it will stall the whole program, and the whole point of using
893	events is to stay interactive.	1028	events is to stay interactive.
894		1029
895	It is fine, however, to call C<< ->recv >> when the user of your module	1030	It is fine, however, to call C<< ->recv >> when the user of your module
896	requests it (i.e. if you create a http request object ad have a method	1031	requests it (i.e. if you create a http request object ad have a method
897	called C<results> that returns the results, it should call C<< ->recv >>	1032	called C<results> that returns the results, it may call C<< ->recv >>
898	freely, as the user of your module knows what she is doing. always).	1033	freely, as the user of your module knows what she is doing. Always).
899		1034
900	=head1 WHAT TO DO IN THE MAIN PROGRAM	1035	=head1 WHAT TO DO IN THE MAIN PROGRAM
901		1036
902	There will always be a single main program - the only place that should	1037	There will always be a single main program - the only place that should
903	dictate which event model to use.	1038	dictate which event model to use.
904		1039
905	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1040	If the program is not event-based, it need not do anything special, even
906	do anything special (it does not need to be event-based) and let AnyEvent	1041	when it depends on a module that uses an AnyEvent. If the program itself
907	decide which implementation to chose if some module relies on it.	1042	uses AnyEvent, but does not care which event loop is used, all it needs
		1043	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1044	available loop implementation.
908		1045
909	If the main program relies on a specific event model - for example, in	1046	If the main program relies on a specific event model - for example, in
910	Gtk2 programs you have to rely on the Glib module - you should load the	1047	Gtk2 programs you have to rely on the Glib module - you should load the
911	event module before loading AnyEvent or any module that uses it: generally	1048	event module before loading AnyEvent or any module that uses it: generally
912	speaking, you should load it as early as possible. The reason is that	1049	speaking, you should load it as early as possible. The reason is that
913	modules might create watchers when they are loaded, and AnyEvent will	1050	modules might create watchers when they are loaded, and AnyEvent will
914	decide on the event model to use as soon as it creates watchers, and it	1051	decide on the event model to use as soon as it creates watchers, and it
915	might chose the wrong one unless you load the correct one yourself.	1052	might choose the wrong one unless you load the correct one yourself.
916		1053
917	You can chose to use a pure-perl implementation by loading the	1054	You can chose to use a pure-perl implementation by loading the
918	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1055	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
919	everywhere, but letting AnyEvent chose the model is generally better.	1056	everywhere, but letting AnyEvent chose the model is generally better.
920		1057
…		…
938	=head1 OTHER MODULES	1075	=head1 OTHER MODULES
939		1076
940	The following is a non-exhaustive list of additional modules that use	1077	The following is a non-exhaustive list of additional modules that use
941	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1078	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
942	modules and other event loops in the same program. Some of the modules	1079	modules and other event loops in the same program. Some of the modules
943	come with AnyEvent, most are available via CPAN.	1080	come as part of AnyEvent, the others are available via CPAN.
944		1081
945	=over 4	1082	=over 4
946		1083
947	=item L<AnyEvent::Util>	1084	=item L<AnyEvent::Util>
948		1085
949	Contains various utility functions that replace often-used but blocking	1086	Contains various utility functions that replace often-used blocking
950	functions such as C<inet_aton> by event-/callback-based versions.	1087	functions such as C<inet_aton> with event/callback-based versions.
951		1088
952	=item L<AnyEvent::Socket>	1089	=item L<AnyEvent::Socket>
953		1090
954	Provides various utility functions for (internet protocol) sockets,	1091	Provides various utility functions for (internet protocol) sockets,
955	addresses and name resolution. Also functions to create non-blocking tcp	1092	addresses and name resolution. Also functions to create non-blocking tcp
…		…
957		1094
958	=item L<AnyEvent::Handle>	1095	=item L<AnyEvent::Handle>
959		1096
960	Provide read and write buffers, manages watchers for reads and writes,	1097	Provide read and write buffers, manages watchers for reads and writes,
961	supports raw and formatted I/O, I/O queued and fully transparent and	1098	supports raw and formatted I/O, I/O queued and fully transparent and
962	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1099	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
963		1100
964	=item L<AnyEvent::DNS>	1101	=item L<AnyEvent::DNS>
965		1102
966	Provides rich asynchronous DNS resolver capabilities.	1103	Provides rich asynchronous DNS resolver capabilities.
967		1104
		1105	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1106
		1107	Implement event-based interfaces to the protocols of the same name (for
		1108	the curious, IGS is the International Go Server and FCP is the Freenet
		1109	Client Protocol).
		1110
		1111	=item L<AnyEvent::Handle::UDP>
		1112
		1113	Here be danger!
		1114
		1115	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1116	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1117	its use of a stream-based API with a protocol that isn't streamable, that
		1118	the only way to improve it is to delete it.
		1119
		1120	It features data corruption (but typically only under load) and general
		1121	confusion. On top, the author is not only clueless about UDP but also
		1122	fact-resistant - some gems of his understanding: "connect doesn't work
		1123	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1124	packets", "I don't need to implement proper error checking as UDP doesn't
		1125	support error checking" and so on - he doesn't even understand what's
		1126	wrong with his module when it is explained to him.
		1127
968	=item L<AnyEvent::HTTP>	1128	=item L<AnyEvent::DBI>
969		1129
970	A simple-to-use HTTP library that is capable of making a lot of concurrent	1130	Executes L<DBI> requests asynchronously in a proxy process for you,
971	HTTP requests.	1131	notifying you in an event-based way when the operation is finished.
		1132
		1133	=item L<AnyEvent::AIO>
		1134
		1135	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1136	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1137	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1138	file I/O, and much more.
972		1139
973	=item L<AnyEvent::HTTPD>	1140	=item L<AnyEvent::HTTPD>
974		1141
975	Provides a simple web application server framework.	1142	A simple embedded webserver.
976		1143
977	=item L<AnyEvent::FastPing>	1144	=item L<AnyEvent::FastPing>
978		1145
979	The fastest ping in the west.	1146	The fastest ping in the west.
980		1147
981	=item L<AnyEvent::DBI>
982
983	Executes L<DBI> requests asynchronously in a proxy process.
984
985	=item L<AnyEvent::AIO>
986
987	Truly asynchronous I/O, should be in the toolbox of every event
988	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
989	together.
990
991	=item L<AnyEvent::BDB>
992
993	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
994	L<BDB> and AnyEvent together.
995
996	=item L<AnyEvent::GPSD>
997
998	A non-blocking interface to gpsd, a daemon delivering GPS information.
999
1000	=item L<AnyEvent::IRC>
1001
1002	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1003
1004	=item L<AnyEvent::XMPP>
1005
1006	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1007	Net::XMPP2>.
1008
1009	=item L<AnyEvent::IGS>
1010
1011	A non-blocking interface to the Internet Go Server protocol (used by
1012	L<App::IGS>).
1013
1014	=item L<Net::FCP>
1015
1016	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1017	of AnyEvent.
1018
1019	=item L<Event::ExecFlow>
1020
1021	High level API for event-based execution flow control.
1022
1023	=item L<Coro>	1148	=item L<Coro>
1024		1149
1025	Has special support for AnyEvent via L<Coro::AnyEvent>.	1150	Has special support for AnyEvent via L<Coro::AnyEvent>.
1026		1151
1027	=back	1152	=back
1028		1153
1029	=cut	1154	=cut
1030		1155
1031	package AnyEvent;	1156	package AnyEvent;
1032		1157
1033	no warnings;	1158	# basically a tuned-down version of common::sense
1034	use strict qw(vars subs);	1159	sub common_sense {
		1160	# from common:.sense 3.3
		1161	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf3\x0f\xc0\xf0\xfc\x33\x00";
		1162	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1163	$^H |= 0x00000600;
		1164	}
1035		1165
		1166	BEGIN { AnyEvent::common_sense }
		1167
1036	use Carp;	1168	use Carp ();
1037		1169
1038	our $VERSION = 4.801;	1170	our $VERSION = '5.271';
1039	our $MODEL;	1171	our $MODEL;
1040		1172
1041	our $AUTOLOAD;	1173	our $AUTOLOAD;
1042	our @ISA;	1174	our @ISA;
1043		1175
1044	our @REGISTRY;	1176	our @REGISTRY;
1045		1177
1046	our $WIN32;	1178	our $VERBOSE;
1047		1179
1048	BEGIN {	1180	BEGIN {
1049	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1181	require "AnyEvent/constants.pl";
		1182
1050	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1183	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1051		1184
1052	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1185	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1053	if ${^TAINT};	1186	if ${^TAINT};
1054	}
1055		1187
1056	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1188	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1189
		1190	}
		1191
		1192	our $MAX_SIGNAL_LATENCY = 10;
1057		1193
1058	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1194	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1059		1195
1060	{	1196	{
1061	my $idx;	1197	my $idx;
…		…
1063	for reverse split /\s*,\s*/,	1199	for reverse split /\s*,\s*/,
1064	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1200	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1065	}	1201	}
1066		1202
1067	my @models = (	1203	my @models = (
1068	[EV:: => AnyEvent::Impl::EV::],	1204	[EV:: => AnyEvent::Impl::EV:: , 1],
1069	[Event:: => AnyEvent::Impl::Event::],
1070	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1205	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1071	# everything below here will not be autoprobed	1206	# everything below here will not (normally) be autoprobed
1072	# as the pureperl backend should work everywhere	1207	# as the pureperl backend should work everywhere
1073	# and is usually faster	1208	# and is usually faster
		1209	[Event:: => AnyEvent::Impl::Event::, 1],
1074	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1210	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1075	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1211	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1212	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1076	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1213	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		1214	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1077	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1215	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1078	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1079	[Wx:: => AnyEvent::Impl::POE::],	1216	[Wx:: => AnyEvent::Impl::POE::],
1080	[Prima:: => AnyEvent::Impl::POE::],	1217	[Prima:: => AnyEvent::Impl::POE::],
1081	# IO::Async is just too broken - we would need workarounds for its	1218	# IO::Async is just too broken - we would need workarounds for its
1082	# byzantine signal and broken child handling, among others.	1219	# byzantine signal and broken child handling, among others.
1083	# IO::Async is rather hard to detect, as it doesn't have any	1220	# IO::Async is rather hard to detect, as it doesn't have any
1084	# obvious default class.	1221	# obvious default class.
1085	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1222	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1086	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1223	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1087	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1224	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1225	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1088	);	1226	);
1089		1227
1090	our %method = map +($_ => 1),	1228	our %method = map +($_ => 1),
1091	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1229	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1092		1230
1093	our @post_detect;	1231	our @post_detect;
1094		1232
1095	sub post_detect(&) {	1233	sub post_detect(&) {
1096	my ($cb) = @_;	1234	my ($cb) = @_;
1097		1235
1098	if ($MODEL) {
1099	$cb->();
1100
1101	1
1102	} else {
1103	push @post_detect, $cb;	1236	push @post_detect, $cb;
1104		1237
1105	defined wantarray	1238	defined wantarray
1106	? bless \$cb, "AnyEvent::Util::postdetect"	1239	? bless \$cb, "AnyEvent::Util::postdetect"
1107	: ()	1240	: ()
1108	}
1109	}	1241	}
1110		1242
1111	sub AnyEvent::Util::postdetect::DESTROY {	1243	sub AnyEvent::Util::postdetect::DESTROY {
1112	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1244	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1113	}	1245	}
1114		1246
1115	sub detect() {	1247	sub detect() {
		1248	# free some memory
		1249	*detect = sub () { $MODEL };
		1250
		1251	local $!; # for good measure
		1252	local $SIG{__DIE__};
		1253
		1254	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1255	my $model = "AnyEvent::Impl::$1";
		1256	if (eval "require $model") {
		1257	$MODEL = $model;
		1258	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1259	} else {
		1260	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1261	}
		1262	}
		1263
		1264	# check for already loaded models
1116	unless ($MODEL) {	1265	unless ($MODEL) {
1117	no strict 'refs';	1266	for (@REGISTRY, @models) {
1118	local $SIG{__DIE__};	1267	my ($package, $model) = @$_;
1119		1268	if (${"$package\::VERSION"} > 0) {
1120	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1121	my $model = "AnyEvent::Impl::$1";
1122	if (eval "require $model") {	1269	if (eval "require $model") {
1123	$MODEL = $model;	1270	$MODEL = $model;
1124	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1271	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1125	} else {	1272	last;
1126	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1273	}
1127	}	1274	}
1128	}	1275	}
1129		1276
1130	# check for already loaded models
1131	unless ($MODEL) {	1277	unless ($MODEL) {
		1278	# try to autoload a model
1132	for (@REGISTRY, @models) {	1279	for (@REGISTRY, @models) {
1133	my ($package, $model) = @$_;	1280	my ($package, $model, $autoload) = @$_;
		1281	if (
		1282	$autoload
		1283	and eval "require $package"
1134	if (${"$package\::VERSION"} > 0) {	1284	and ${"$package\::VERSION"} > 0
1135	if (eval "require $model") {	1285	and eval "require $model"
		1286	) {
1136	$MODEL = $model;	1287	$MODEL = $model;
1137	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1288	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1138	last;	1289	last;
1139	}
1140	}	1290	}
1141	}	1291	}
1142		1292
1143	unless ($MODEL) {
1144	# try to load a model
1145
1146	for (@REGISTRY, @models) {
1147	my ($package, $model) = @$_;
1148	if (eval "require $package"
1149	and ${"$package\::VERSION"} > 0
1150	and eval "require $model") {
1151	$MODEL = $model;
1152	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1153	last;
1154	}
1155	}
1156
1157	$MODEL	1293	$MODEL
1158	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1294	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1159	}
1160	}	1295	}
1161
1162	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1163
1164	unshift @ISA, $MODEL;
1165
1166	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1167
1168	(shift @post_detect)->() while @post_detect;
1169	}	1296	}
		1297
		1298	@models = (); # free probe data
		1299
		1300	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1301	unshift @ISA, $MODEL;
		1302
		1303	# now nuke some methods that are overriden by the backend.
		1304	# SUPER is not allowed.
		1305	for (qw(time signal child idle)) {
		1306	undef &{"AnyEvent::Base::$_"}
		1307	if defined &{"$MODEL\::$_"};
		1308	}
		1309
		1310	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1311
		1312	(shift @post_detect)->() while @post_detect;
		1313
		1314	*post_detect = sub(&) {
		1315	shift->();
		1316
		1317	undef
		1318	};
1170		1319
1171	$MODEL	1320	$MODEL
1172	}	1321	}
1173		1322
1174	sub AUTOLOAD {	1323	sub AUTOLOAD {
1175	(my $func = $AUTOLOAD) =~ s/.*://;	1324	(my $func = $AUTOLOAD) =~ s/.*://;
1176		1325
1177	$method{$func}	1326	$method{$func}
1178	or croak "$func: not a valid method for AnyEvent objects";	1327	or Carp::croak "$func: not a valid AnyEvent class method";
1179		1328
1180	detect unless $MODEL;	1329	detect;
1181		1330
1182	my $class = shift;	1331	my $class = shift;
1183	$class->$func (@_);	1332	$class->$func (@_);
1184	}	1333	}
1185		1334
…		…
1188	# allow only one watcher per fd, so we dup it to get a different one).	1337	# allow only one watcher per fd, so we dup it to get a different one).
1189	sub _dupfh($$;$$) {	1338	sub _dupfh($$;$$) {
1190	my ($poll, $fh, $r, $w) = @_;	1339	my ($poll, $fh, $r, $w) = @_;
1191		1340
1192	# cygwin requires the fh mode to be matching, unix doesn't	1341	# cygwin requires the fh mode to be matching, unix doesn't
1193	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1342	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1194		1343
1195	open my $fh2, "$mode&", $fh	1344	open my $fh2, $mode, $fh
1196	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1345	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1197		1346
1198	# we assume CLOEXEC is already set by perl in all important cases	1347	# we assume CLOEXEC is already set by perl in all important cases
1199		1348
1200	($fh2, $rw)	1349	($fh2, $rw)
1201	}	1350	}
1202		1351
		1352	=head1 SIMPLIFIED AE API
		1353
		1354	Starting with version 5.0, AnyEvent officially supports a second, much
		1355	simpler, API that is designed to reduce the calling, typing and memory
		1356	overhead by using function call syntax and a fixed number of parameters.
		1357
		1358	See the L<AE> manpage for details.
		1359
		1360	=cut
		1361
		1362	package AE;
		1363
		1364	our $VERSION = $AnyEvent::VERSION;
		1365
		1366	# fall back to the main API by default - backends and AnyEvent::Base
		1367	# implementations can overwrite these.
		1368
		1369	sub io($$$) {
		1370	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1371	}
		1372
		1373	sub timer($$$) {
		1374	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1375	}
		1376
		1377	sub signal($$) {
		1378	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1379	}
		1380
		1381	sub child($$) {
		1382	AnyEvent->child (pid => $_[0], cb => $_[1])
		1383	}
		1384
		1385	sub idle($) {
		1386	AnyEvent->idle (cb => $_[0])
		1387	}
		1388
		1389	sub cv(;&) {
		1390	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1391	}
		1392
		1393	sub now() {
		1394	AnyEvent->now
		1395	}
		1396
		1397	sub now_update() {
		1398	AnyEvent->now_update
		1399	}
		1400
		1401	sub time() {
		1402	AnyEvent->time
		1403	}
		1404
1203	package AnyEvent::Base;	1405	package AnyEvent::Base;
1204		1406
1205	# default implementations for many methods	1407	# default implementations for many methods
1206		1408
1207	BEGIN {	1409	sub time {
		1410	eval q{ # poor man's autoloading {}
		1411	# probe for availability of Time::HiRes
1208	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1412	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1413	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1209	*_time = \&Time::HiRes::time;	1414	*AE::time = \&Time::HiRes::time;
1210	# if (eval "use POSIX (); (POSIX::times())...	1415	# if (eval "use POSIX (); (POSIX::times())...
1211	} else {	1416	} else {
		1417	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1212	*_time = sub { time }; # epic fail	1418	*AE::time = sub (){ time }; # epic fail
		1419	}
		1420
		1421	*time = sub { AE::time }; # different prototypes
		1422	};
		1423	die if $@;
		1424
		1425	&time
		1426	}
		1427
		1428	*now = \&time;
		1429
		1430	sub now_update { }
		1431
		1432	# default implementation for ->condvar
		1433
		1434	sub condvar {
		1435	eval q{ # poor man's autoloading {}
		1436	*condvar = sub {
		1437	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1438	};
		1439
		1440	*AE::cv = sub (;&) {
		1441	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1442	};
		1443	};
		1444	die if $@;
		1445
		1446	&condvar
		1447	}
		1448
		1449	# default implementation for ->signal
		1450
		1451	our $HAVE_ASYNC_INTERRUPT;
		1452
		1453	sub _have_async_interrupt() {
		1454	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1455	&& eval "use Async::Interrupt 1.02 (); 1")
		1456	unless defined $HAVE_ASYNC_INTERRUPT;
		1457
		1458	$HAVE_ASYNC_INTERRUPT
		1459	}
		1460
		1461	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1462	our (%SIG_ASY, %SIG_ASY_W);
		1463	our ($SIG_COUNT, $SIG_TW);
		1464
		1465	# install a dummy wakeup watcher to reduce signal catching latency
		1466	# used by Impls
		1467	sub _sig_add() {
		1468	unless ($SIG_COUNT++) {
		1469	# try to align timer on a full-second boundary, if possible
		1470	my $NOW = AE::now;
		1471
		1472	$SIG_TW = AE::timer
		1473	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1474	$MAX_SIGNAL_LATENCY,
		1475	sub { } # just for the PERL_ASYNC_CHECK
		1476	;
1213	}	1477	}
1214	}	1478	}
1215		1479
1216	sub time { _time }	1480	sub _sig_del {
1217	sub now { _time }	1481	undef $SIG_TW
1218	sub now_update { }	1482	unless --$SIG_COUNT;
1219
1220	# default implementation for ->condvar
1221
1222	sub condvar {
1223	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1224	}	1483	}
1225		1484
1226	# default implementation for ->signal	1485	our $_sig_name_init; $_sig_name_init = sub {
		1486	eval q{ # poor man's autoloading {}
		1487	undef $_sig_name_init;
1227		1488
1228	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1489	if (_have_async_interrupt) {
		1490	*sig2num = \&Async::Interrupt::sig2num;
		1491	*sig2name = \&Async::Interrupt::sig2name;
		1492	} else {
		1493	require Config;
1229		1494
1230	sub _signal_exec {	1495	my %signame2num;
1231	sysread $SIGPIPE_R, my $dummy, 4;	1496	@signame2num{ split ' ', $Config::Config{sig_name} }
		1497	= split ' ', $Config::Config{sig_num};
1232		1498
1233	while (%SIG_EV) {	1499	my @signum2name;
1234	for (keys %SIG_EV) {	1500	@signum2name[values %signame2num] = keys %signame2num;
1235	delete $SIG_EV{$_};	1501
1236	$_->() for values %{ $SIG_CB{$_} || {} };	1502	*sig2num = sub($) {
		1503	$_[0] > 0 ? shift : $signame2num{+shift}
		1504	};
		1505	*sig2name = sub ($) {
		1506	$_[0] > 0 ? $signum2name[+shift] : shift
		1507	};
1237	}	1508	}
1238	}	1509	};
1239	}	1510	die if $@;
		1511	};
		1512
		1513	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1514	sub sig2name($) { &$_sig_name_init; &sig2name }
1240		1515
1241	sub signal {	1516	sub signal {
1242	my (undef, %arg) = @_;	1517	eval q{ # poor man's autoloading {}
		1518	# probe for availability of Async::Interrupt
		1519	if (_have_async_interrupt) {
		1520	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1243		1521
1244	unless ($SIGPIPE_R) {	1522	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1245	require Fcntl;	1523	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1246		1524
1247	if (AnyEvent::WIN32) {
1248	require AnyEvent::Util;
1249
1250	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1251	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1252	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1253	} else {	1525	} else {
		1526	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1527
		1528	if (AnyEvent::WIN32) {
		1529	require AnyEvent::Util;
		1530
		1531	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1532	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1533	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1534	} else {
1254	pipe $SIGPIPE_R, $SIGPIPE_W;	1535	pipe $SIGPIPE_R, $SIGPIPE_W;
1255	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1536	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1256	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1537	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1257		1538
1258	# not strictly required, as $^F is normally 2, but let's make sure...	1539	# not strictly required, as $^F is normally 2, but let's make sure...
1259	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1540	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1260	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1541	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1542	}
		1543
		1544	$SIGPIPE_R
		1545	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1546
		1547	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1261	}	1548	}
1262		1549
1263	$SIGPIPE_R	1550	*signal = $HAVE_ASYNC_INTERRUPT
1264	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1551	? sub {
		1552	my (undef, %arg) = @_;
1265		1553
1266	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1554	# async::interrupt
1267	}
1268
1269	my $signal = uc $arg{signal}	1555	my $signal = sig2num $arg{signal};
1270	or Carp::croak "required option 'signal' is missing";
1271
1272	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1556	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1557
		1558	$SIG_ASY{$signal} ||= new Async::Interrupt
		1559	cb => sub { undef $SIG_EV{$signal} },
		1560	signal => $signal,
		1561	pipe => [$SIGPIPE_R->filenos],
		1562	pipe_autodrain => 0,
		1563	;
		1564
		1565	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1566	}
		1567	: sub {
		1568	my (undef, %arg) = @_;
		1569
		1570	# pure perl
		1571	my $signal = sig2name $arg{signal};
		1572	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1573
1273	$SIG{$signal} ||= sub {	1574	$SIG{$signal} ||= sub {
1274	local $!;	1575	local $!;
1275	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1576	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1276	undef $SIG_EV{$signal};	1577	undef $SIG_EV{$signal};
		1578	};
		1579
		1580	# can't do signal processing without introducing races in pure perl,
		1581	# so limit the signal latency.
		1582	_sig_add;
		1583
		1584	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1585	}
		1586	;
		1587
		1588	*AnyEvent::Base::signal::DESTROY = sub {
		1589	my ($signal, $cb) = @{$_[0]};
		1590
		1591	_sig_del;
		1592
		1593	delete $SIG_CB{$signal}{$cb};
		1594
		1595	$HAVE_ASYNC_INTERRUPT
		1596	? delete $SIG_ASY{$signal}
		1597	: # delete doesn't work with older perls - they then
		1598	# print weird messages, or just unconditionally exit
		1599	# instead of getting the default action.
		1600	undef $SIG{$signal}
		1601	unless keys %{ $SIG_CB{$signal} };
		1602	};
		1603
		1604	*_signal_exec = sub {
		1605	$HAVE_ASYNC_INTERRUPT
		1606	? $SIGPIPE_R->drain
		1607	: sysread $SIGPIPE_R, (my $dummy), 9;
		1608
		1609	while (%SIG_EV) {
		1610	for (keys %SIG_EV) {
		1611	delete $SIG_EV{$_};
		1612	$_->() for values %{ $SIG_CB{$_} || {} };
		1613	}
		1614	}
		1615	};
1277	};	1616	};
		1617	die if $@;
1278		1618
1279	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1619	&signal
1280	}
1281
1282	sub AnyEvent::Base::signal::DESTROY {
1283	my ($signal, $cb) = @{$_[0]};
1284
1285	delete $SIG_CB{$signal}{$cb};
1286
1287	# delete doesn't work with older perls - they then
1288	# print weird messages, or just unconditionally exit
1289	# instead of getting the default action.
1290	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1291	}	1620	}
1292		1621
1293	# default implementation for ->child	1622	# default implementation for ->child
1294		1623
1295	our %PID_CB;	1624	our %PID_CB;
1296	our $CHLD_W;	1625	our $CHLD_W;
1297	our $CHLD_DELAY_W;	1626	our $CHLD_DELAY_W;
1298	our $WNOHANG;	1627	our $WNOHANG;
1299		1628
1300	sub _sigchld {	1629	# used by many Impl's
1301	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1630	sub _emit_childstatus($$) {
		1631	my (undef, $rpid, $rstatus) = @_;
		1632
		1633	$_->($rpid, $rstatus)
1302	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1634	for values %{ $PID_CB{$rpid} || {} },
1303	(values %{ $PID_CB{0} || {} });	1635	values %{ $PID_CB{0} || {} };
1304	}
1305	}	1636	}
1306		1637
1307	sub child {	1638	sub child {
		1639	eval q{ # poor man's autoloading {}
		1640	*_sigchld = sub {
		1641	my $pid;
		1642
		1643	AnyEvent->_emit_childstatus ($pid, $?)
		1644	while ($pid = waitpid -1, $WNOHANG) > 0;
		1645	};
		1646
		1647	*child = sub {
1308	my (undef, %arg) = @_;	1648	my (undef, %arg) = @_;
1309		1649
1310	defined (my $pid = $arg{pid} + 0)	1650	defined (my $pid = $arg{pid} + 0)
1311	or Carp::croak "required option 'pid' is missing";	1651	or Carp::croak "required option 'pid' is missing";
1312		1652
1313	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1653	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1314		1654
		1655	# WNOHANG is almost cetrainly 1 everywhere
		1656	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1657	? 1
1315	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1658	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1316		1659
1317	unless ($CHLD_W) {	1660	unless ($CHLD_W) {
1318	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1661	$CHLD_W = AE::signal CHLD => \&_sigchld;
1319	# child could be a zombie already, so make at least one round	1662	# child could be a zombie already, so make at least one round
1320	&_sigchld;	1663	&_sigchld;
1321	}	1664	}
1322		1665
1323	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1666	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1324	}	1667	};
1325		1668
1326	sub AnyEvent::Base::child::DESTROY {	1669	*AnyEvent::Base::child::DESTROY = sub {
1327	my ($pid, $cb) = @{$_[0]};	1670	my ($pid, $cb) = @{$_[0]};
1328		1671
1329	delete $PID_CB{$pid}{$cb};	1672	delete $PID_CB{$pid}{$cb};
1330	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1673	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1331		1674
1332	undef $CHLD_W unless keys %PID_CB;	1675	undef $CHLD_W unless keys %PID_CB;
		1676	};
		1677	};
		1678	die if $@;
		1679
		1680	&child
1333	}	1681	}
1334		1682
1335	# idle emulation is done by simply using a timer, regardless	1683	# idle emulation is done by simply using a timer, regardless
1336	# of whether the process is idle or not, and not letting	1684	# of whether the process is idle or not, and not letting
1337	# the callback use more than 50% of the time.	1685	# the callback use more than 50% of the time.
1338	sub idle {	1686	sub idle {
		1687	eval q{ # poor man's autoloading {}
		1688	*idle = sub {
1339	my (undef, %arg) = @_;	1689	my (undef, %arg) = @_;
1340		1690
1341	my ($cb, $w, $rcb) = $arg{cb};	1691	my ($cb, $w, $rcb) = $arg{cb};
1342		1692
1343	$rcb = sub {	1693	$rcb = sub {
1344	if ($cb) {	1694	if ($cb) {
1345	$w = _time;	1695	$w = _time;
1346	&$cb;	1696	&$cb;
1347	$w = _time - $w;	1697	$w = _time - $w;
1348		1698
1349	# never use more then 50% of the time for the idle watcher,	1699	# never use more then 50% of the time for the idle watcher,
1350	# within some limits	1700	# within some limits
1351	$w = 0.0001 if $w < 0.0001;	1701	$w = 0.0001 if $w < 0.0001;
1352	$w = 5 if $w > 5;	1702	$w = 5 if $w > 5;
1353		1703
1354	$w = AnyEvent->timer (after => $w, cb => $rcb);	1704	$w = AE::timer $w, 0, $rcb;
1355	} else {	1705	} else {
1356	# clean up...	1706	# clean up...
1357	undef $w;	1707	undef $w;
1358	undef $rcb;	1708	undef $rcb;
		1709	}
		1710	};
		1711
		1712	$w = AE::timer 0.05, 0, $rcb;
		1713
		1714	bless \\$cb, "AnyEvent::Base::idle"
1359	}	1715	};
		1716
		1717	*AnyEvent::Base::idle::DESTROY = sub {
		1718	undef $${$_[0]};
		1719	};
1360	};	1720	};
		1721	die if $@;
1361		1722
1362	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1723	&idle
1363
1364	bless \\$cb, "AnyEvent::Base::idle"
1365	}
1366
1367	sub AnyEvent::Base::idle::DESTROY {
1368	undef $${$_[0]};
1369	}	1724	}
1370		1725
1371	package AnyEvent::CondVar;	1726	package AnyEvent::CondVar;
1372		1727
1373	our @ISA = AnyEvent::CondVar::Base::;	1728	our @ISA = AnyEvent::CondVar::Base::;
1374		1729
1375	package AnyEvent::CondVar::Base;	1730	package AnyEvent::CondVar::Base;
1376		1731
1377	use overload	1732	#use overload
1378	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1733	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1379	fallback => 1;	1734	# fallback => 1;
		1735
		1736	# save 300+ kilobytes by dirtily hardcoding overloading
		1737	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1738	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1739	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1740	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1741
		1742	our $WAITING;
1380		1743
1381	sub _send {	1744	sub _send {
1382	# nop	1745	# nop
1383	}	1746	}
1384		1747
…		…
1397	sub ready {	1760	sub ready {
1398	$_[0]{_ae_sent}	1761	$_[0]{_ae_sent}
1399	}	1762	}
1400		1763
1401	sub _wait {	1764	sub _wait {
		1765	$WAITING
		1766	and !$_[0]{_ae_sent}
		1767	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1768
		1769	local $WAITING = 1;
1402	AnyEvent->one_event while !$_[0]{_ae_sent};	1770	AnyEvent->one_event while !$_[0]{_ae_sent};
1403	}	1771	}
1404		1772
1405	sub recv {	1773	sub recv {
1406	$_[0]->_wait;	1774	$_[0]->_wait;
…		…
1408	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1776	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1409	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1777	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1410	}	1778	}
1411		1779
1412	sub cb {	1780	sub cb {
1413	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1781	my $cv = shift;
		1782
		1783	@_
		1784	and $cv->{_ae_cb} = shift
		1785	and $cv->{_ae_sent}
		1786	and (delete $cv->{_ae_cb})->($cv);
		1787
1414	$_[0]{_ae_cb}	1788	$cv->{_ae_cb}
1415	}	1789	}
1416		1790
1417	sub begin {	1791	sub begin {
1418	++$_[0]{_ae_counter};	1792	++$_[0]{_ae_counter};
1419	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1793	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1468	C<PERL_ANYEVENT_MODEL>.	1842	C<PERL_ANYEVENT_MODEL>.
1469		1843
1470	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1844	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1471	model it chooses.	1845	model it chooses.
1472		1846
		1847	When set to C<8> or higher, then AnyEvent will report extra information on
		1848	which optional modules it loads and how it implements certain features.
		1849
1473	=item C<PERL_ANYEVENT_STRICT>	1850	=item C<PERL_ANYEVENT_STRICT>
1474		1851
1475	AnyEvent does not do much argument checking by default, as thorough	1852	AnyEvent does not do much argument checking by default, as thorough
1476	argument checking is very costly. Setting this variable to a true value	1853	argument checking is very costly. Setting this variable to a true value
1477	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1854	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1478	check the arguments passed to most method calls. If it finds any problems,	1855	check the arguments passed to most method calls. If it finds any problems,
1479	it will croak.	1856	it will croak.
1480		1857
1481	In other words, enables "strict" mode.	1858	In other words, enables "strict" mode.
1482		1859
1483	Unlike C<use strict>, it is definitely recommended to keep it off in	1860	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1484	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1861	>>, it is definitely recommended to keep it off in production. Keeping
1485	developing programs can be very useful, however.	1862	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1863	can be very useful, however.
1486		1864
1487	=item C<PERL_ANYEVENT_MODEL>	1865	=item C<PERL_ANYEVENT_MODEL>
1488		1866
1489	This can be used to specify the event model to be used by AnyEvent, before	1867	This can be used to specify the event model to be used by AnyEvent, before
1490	auto detection and -probing kicks in. It must be a string consisting	1868	auto detection and -probing kicks in. It must be a string consisting
…		…
1552		1930
1553	When neither C<ca_file> nor C<ca_path> was specified during	1931	When neither C<ca_file> nor C<ca_path> was specified during
1554	L<AnyEvent::TLS> context creation, and either of these environment	1932	L<AnyEvent::TLS> context creation, and either of these environment
1555	variables exist, they will be used to specify CA certificate locations	1933	variables exist, they will be used to specify CA certificate locations
1556	instead of a system-dependent default.	1934	instead of a system-dependent default.
		1935
		1936	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1937
		1938	When these are set to C<1>, then the respective modules are not
		1939	loaded. Mostly good for testing AnyEvent itself.
1557		1940
1558	=back	1941	=back
1559		1942
1560	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1943	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1561		1944
…		…
1619	warn "read: $input\n"; # output what has been read	2002	warn "read: $input\n"; # output what has been read
1620	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2003	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1621	},	2004	},
1622	);	2005	);
1623		2006
1624	my $time_watcher; # can only be used once
1625
1626	sub new_timer {
1627	$timer = AnyEvent->timer (after => 1, cb => sub {	2007	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1628	warn "timeout\n"; # print 'timeout' about every second	2008	warn "timeout\n"; # print 'timeout' at most every second
1629	&new_timer; # and restart the time
1630	});	2009	});
1631	}
1632
1633	new_timer; # create first timer
1634		2010
1635	$cv->recv; # wait until user enters /^q/i	2011	$cv->recv; # wait until user enters /^q/i
1636		2012
1637	=head1 REAL-WORLD EXAMPLE	2013	=head1 REAL-WORLD EXAMPLE
1638		2014
…		…
1711		2087
1712	The actual code goes further and collects all errors (C<die>s, exceptions)	2088	The actual code goes further and collects all errors (C<die>s, exceptions)
1713	that occurred during request processing. The C<result> method detects	2089	that occurred during request processing. The C<result> method detects
1714	whether an exception as thrown (it is stored inside the $txn object)	2090	whether an exception as thrown (it is stored inside the $txn object)
1715	and just throws the exception, which means connection errors and other	2091	and just throws the exception, which means connection errors and other
1716	problems get reported tot he code that tries to use the result, not in a	2092	problems get reported to the code that tries to use the result, not in a
1717	random callback.	2093	random callback.
1718		2094
1719	All of this enables the following usage styles:	2095	All of this enables the following usage styles:
1720		2096
1721	1. Blocking:	2097	1. Blocking:
…		…
1769	through AnyEvent. The benchmark creates a lot of timers (with a zero	2145	through AnyEvent. The benchmark creates a lot of timers (with a zero
1770	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2146	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1771	which it is), lets them fire exactly once and destroys them again.	2147	which it is), lets them fire exactly once and destroys them again.
1772		2148
1773	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2149	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1774	distribution.	2150	distribution. It uses the L<AE> interface, which makes a real difference
		2151	for the EV and Perl backends only.
1775		2152
1776	=head3 Explanation of the columns	2153	=head3 Explanation of the columns
1777		2154
1778	I<watcher> is the number of event watchers created/destroyed. Since	2155	I<watcher> is the number of event watchers created/destroyed. Since
1779	different event models feature vastly different performances, each event	2156	different event models feature vastly different performances, each event
…		…
1800	watcher.	2177	watcher.
1801		2178
1802	=head3 Results	2179	=head3 Results
1803		2180
1804	name watchers bytes create invoke destroy comment	2181	name watchers bytes create invoke destroy comment
1805	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2182	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1806	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2183	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1807	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2184	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1808	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2185	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1809	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2186	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1810	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2187	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1811	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2188	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1812	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2189	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1813	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2190	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1814	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2191	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1815	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2192	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1816	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2193	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1817		2194
1818	=head3 Discussion	2195	=head3 Discussion
1819		2196
1820	The benchmark does I<not> measure scalability of the event loop very	2197	The benchmark does I<not> measure scalability of the event loop very
1821	well. For example, a select-based event loop (such as the pure perl one)	2198	well. For example, a select-based event loop (such as the pure perl one)
…		…
1833	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2210	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1834	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2211	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1835	cycles with POE.	2212	cycles with POE.
1836		2213
1837	C<EV> is the sole leader regarding speed and memory use, which are both	2214	C<EV> is the sole leader regarding speed and memory use, which are both
1838	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2215	maximal/minimal, respectively. When using the L<AE> API there is zero
		2216	overhead (when going through the AnyEvent API create is about 5-6 times
		2217	slower, with other times being equal, so still uses far less memory than
1839	far less memory than any other event loop and is still faster than Event	2218	any other event loop and is still faster than Event natively).
1840	natively.
1841		2219
1842	The pure perl implementation is hit in a few sweet spots (both the	2220	The pure perl implementation is hit in a few sweet spots (both the
1843	constant timeout and the use of a single fd hit optimisations in the perl	2221	constant timeout and the use of a single fd hit optimisations in the perl
1844	interpreter and the backend itself). Nevertheless this shows that it	2222	interpreter and the backend itself). Nevertheless this shows that it
1845	adds very little overhead in itself. Like any select-based backend its	2223	adds very little overhead in itself. Like any select-based backend its
…		…
1919	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2297	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1920	(1%) are active. This mirrors the activity of large servers with many	2298	(1%) are active. This mirrors the activity of large servers with many
1921	connections, most of which are idle at any one point in time.	2299	connections, most of which are idle at any one point in time.
1922		2300
1923	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2301	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1924	distribution.	2302	distribution. It uses the L<AE> interface, which makes a real difference
		2303	for the EV and Perl backends only.
1925		2304
1926	=head3 Explanation of the columns	2305	=head3 Explanation of the columns
1927		2306
1928	I<sockets> is the number of sockets, and twice the number of "servers" (as	2307	I<sockets> is the number of sockets, and twice the number of "servers" (as
1929	each server has a read and write socket end).	2308	each server has a read and write socket end).
…		…
1937	a new one that moves the timeout into the future.	2316	a new one that moves the timeout into the future.
1938		2317
1939	=head3 Results	2318	=head3 Results
1940		2319
1941	name sockets create request	2320	name sockets create request
1942	EV 20000 69.01 11.16	2321	EV 20000 62.66 7.99
1943	Perl 20000 73.32 35.87	2322	Perl 20000 68.32 32.64
1944	IOAsync 20000 157.00 98.14 epoll	2323	IOAsync 20000 174.06 101.15 epoll
1945	IOAsync 20000 159.31 616.06 poll	2324	IOAsync 20000 174.67 610.84 poll
1946	Event 20000 212.62 257.32	2325	Event 20000 202.69 242.91
1947	Glib 20000 651.16 1896.30	2326	Glib 20000 557.01 1689.52
1948	POE 20000 349.67 12317.24 uses POE::Loop::Event	2327	POE 20000 341.54 12086.32 uses POE::Loop::Event
1949		2328
1950	=head3 Discussion	2329	=head3 Discussion
1951		2330
1952	This benchmark I<does> measure scalability and overall performance of the	2331	This benchmark I<does> measure scalability and overall performance of the
1953	particular event loop.	2332	particular event loop.
…		…
2079	As you can see, the AnyEvent + EV combination even beats the	2458	As you can see, the AnyEvent + EV combination even beats the
2080	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2459	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2081	backend easily beats IO::Lambda and POE.	2460	backend easily beats IO::Lambda and POE.
2082		2461
2083	And even the 100% non-blocking version written using the high-level (and	2462	And even the 100% non-blocking version written using the high-level (and
2084	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2463	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2085	large margin, even though it does all of DNS, tcp-connect and socket I/O	2464	higher level ("unoptimised") abstractions by a large margin, even though
2086	in a non-blocking way.	2465	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2087		2466
2088	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2467	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2089	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2468	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2090	part of the IO::lambda distribution and were used without any changes.	2469	part of the IO::Lambda distribution and were used without any changes.
2091		2470
2092		2471
2093	=head1 SIGNALS	2472	=head1 SIGNALS
2094		2473
2095	AnyEvent currently installs handlers for these signals:	2474	AnyEvent currently installs handlers for these signals:
…		…
2100		2479
2101	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2480	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2102	emulation for event loops that do not support them natively. Also, some	2481	emulation for event loops that do not support them natively. Also, some
2103	event loops install a similar handler.	2482	event loops install a similar handler.
2104		2483
2105	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2484	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2106	reset it to default, to avoid losing child exit statuses.	2485	AnyEvent will reset it to default, to avoid losing child exit statuses.
2107		2486
2108	=item SIGPIPE	2487	=item SIGPIPE
2109		2488
2110	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2489	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2111	when AnyEvent gets loaded.	2490	when AnyEvent gets loaded.
…		…
2129	if $SIG{CHLD} eq 'IGNORE';	2508	if $SIG{CHLD} eq 'IGNORE';
2130		2509
2131	$SIG{PIPE} = sub { }	2510	$SIG{PIPE} = sub { }
2132	unless defined $SIG{PIPE};	2511	unless defined $SIG{PIPE};
2133		2512
		2513	=head1 RECOMMENDED/OPTIONAL MODULES
		2514
		2515	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2516	its built-in modules) are required to use it.
		2517
		2518	That does not mean that AnyEvent won't take advantage of some additional
		2519	modules if they are installed.
		2520
		2521	This section explains which additional modules will be used, and how they
		2522	affect AnyEvent's operation.
		2523
		2524	=over 4
		2525
		2526	=item L<Async::Interrupt>
		2527
		2528	This slightly arcane module is used to implement fast signal handling: To
		2529	my knowledge, there is no way to do completely race-free and quick
		2530	signal handling in pure perl. To ensure that signals still get
		2531	delivered, AnyEvent will start an interval timer to wake up perl (and
		2532	catch the signals) with some delay (default is 10 seconds, look for
		2533	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2534
		2535	If this module is available, then it will be used to implement signal
		2536	catching, which means that signals will not be delayed, and the event loop
		2537	will not be interrupted regularly, which is more efficient (and good for
		2538	battery life on laptops).
		2539
		2540	This affects not just the pure-perl event loop, but also other event loops
		2541	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2542
		2543	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2544	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2545	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2546	does nothing for those backends.
		2547
		2548	=item L<EV>
		2549
		2550	This module isn't really "optional", as it is simply one of the backend
		2551	event loops that AnyEvent can use. However, it is simply the best event
		2552	loop available in terms of features, speed and stability: It supports
		2553	the AnyEvent API optimally, implements all the watcher types in XS, does
		2554	automatic timer adjustments even when no monotonic clock is available,
		2555	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2556	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2557	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2558
		2559	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2560	then this module will do nothing for you.
		2561
		2562	=item L<Guard>
		2563
		2564	The guard module, when used, will be used to implement
		2565	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2566	lot less memory), but otherwise doesn't affect guard operation much. It is
		2567	purely used for performance.
		2568
		2569	=item L<JSON> and L<JSON::XS>
		2570
		2571	One of these modules is required when you want to read or write JSON data
		2572	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2573	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2574
		2575	=item L<Net::SSLeay>
		2576
		2577	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2578	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2579	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2580
		2581	=item L<Time::HiRes>
		2582
		2583	This module is part of perl since release 5.008. It will be used when the
		2584	chosen event library does not come with a timing source of its own. The
		2585	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2586	try to use a monotonic clock for timing stability.
		2587
		2588	=back
		2589
		2590
2134	=head1 FORK	2591	=head1 FORK
2135		2592
2136	Most event libraries are not fork-safe. The ones who are usually are	2593	Most event libraries are not fork-safe. The ones who are usually are
2137	because they rely on inefficient but fork-safe C<select> or C<poll>	2594	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2138	calls. Only L<EV> is fully fork-aware.	2595	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2596	are usually badly thought-out hacks that are incompatible with fork in
		2597	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2598	continue event-processing in both parent and child (or both, if you know
		2599	what you are doing).
		2600
		2601	This means that, in general, you cannot fork and do event processing in
		2602	the child if the event library was initialised before the fork (which
		2603	usually happens when the first AnyEvent watcher is created, or the library
		2604	is loaded).
2139		2605
2140	If you have to fork, you must either do so I<before> creating your first	2606	If you have to fork, you must either do so I<before> creating your first
2141	watcher OR you must not use AnyEvent at all in the child.	2607	watcher OR you must not use AnyEvent at all in the child OR you must do
		2608	something completely out of the scope of AnyEvent.
		2609
		2610	The problem of doing event processing in the parent I<and> the child
		2611	is much more complicated: even for backends that I<are> fork-aware or
		2612	fork-safe, their behaviour is not usually what you want: fork clones all
		2613	watchers, that means all timers, I/O watchers etc. are active in both
		2614	parent and child, which is almost never what you want. USing C<exec>
		2615	to start worker children from some kind of manage rprocess is usually
		2616	preferred, because it is much easier and cleaner, at the expense of having
		2617	to have another binary.
2142		2618
2143		2619
2144	=head1 SECURITY CONSIDERATIONS	2620	=head1 SECURITY CONSIDERATIONS
2145		2621
2146	AnyEvent can be forced to load any event model via	2622	AnyEvent can be forced to load any event model via
…		…
2184	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2660	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2185		2661
2186	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2662	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2187	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2663	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2188	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2664	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2189	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2665	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2190		2666
2191	Non-blocking file handles, sockets, TCP clients and	2667	Non-blocking file handles, sockets, TCP clients and
2192	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2668	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2193		2669
2194	Asynchronous DNS: L<AnyEvent::DNS>.	2670	Asynchronous DNS: L<AnyEvent::DNS>.

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